Methicillin-resistant staphylococcus aureus in Melanesian children with haematogenous osteomyelitis from the Central Highlands of Papua New Guinea
- Aglua, Izzard, Jaworski, Jan, Drekore, Jimmy, Urakoko, Bohu, Poka, Harry, Michael, Audrey, Greenhill, Andrew
- Authors: Aglua, Izzard , Jaworski, Jan , Drekore, Jimmy , Urakoko, Bohu , Poka, Harry , Michael, Audrey , Greenhill, Andrew
- Date: 2018
- Type: Text , Journal article
- Relation: International Journal of Pediatrics Vol. 6, no. 10 (2018), p. 8361-8370
- Full Text:
- Reviewed:
- Description: Background: Methicillin-Resistant Staphylococcus aureus (MRSA) has been an important cause of bone infection since the 1940s. Current guidelines recommend targeted antibiotic use for osteomyelitis treatment informed by microbial sensitivity patterns. However, in settings without microbiology facilities, empirical antibiotic use is common. Unrecognized antibiotic resistance potentiates persistence of MRSA with osteomyelitis progression to chronic forms with complications despite antibiotic treatment. Materials and Methods: A prospective observational study was done to identify common etiological agent (s) in bone infection in Melanesian children (that were admitted to the two surgical and one pediatric wards of the SJNM-KUGH in the Simbu province of Papua New Guinea in 2012 and 2017), observe for presence of antimicrobial resistance, and determine effective antibiotic regimes for treatment of bone pediatric osteomyelitis. Seventy pediatric patients presenting from the community with osteomyelitis were recruited, with bone and non-bone specimens sampled, cultured and isolates tested for resistance to common antibiotics. Results: Staphylococcus aureus (S. aureus) was isolated in 67% (47/70) of collected specimens. Of the 47 isolates, there was 91.5% resistance to penicillin, 85.1% resistance to methicillin, 89.4% resistance to oxacillin, 93.6% resistance to ampicillin and 80.9% resistance to ceftriaxone. S. aureus showed 91.5% sensitivity to gentamycin, 93.6% sensitivity to erythromycin, tetracycline and clindamycin, and 95.7% sensitivity to Co-trimoxazole. Conclusion: MRSA was the leading cause of haematogenous osteomyelitis in Melanesian children. S.aureus was isolated mainly from infected long bones of the lower limbs (79%) of children presenting from the community, suggesting a predominantly community-associated MRSA.
- Authors: Aglua, Izzard , Jaworski, Jan , Drekore, Jimmy , Urakoko, Bohu , Poka, Harry , Michael, Audrey , Greenhill, Andrew
- Date: 2018
- Type: Text , Journal article
- Relation: International Journal of Pediatrics Vol. 6, no. 10 (2018), p. 8361-8370
- Full Text:
- Reviewed:
- Description: Background: Methicillin-Resistant Staphylococcus aureus (MRSA) has been an important cause of bone infection since the 1940s. Current guidelines recommend targeted antibiotic use for osteomyelitis treatment informed by microbial sensitivity patterns. However, in settings without microbiology facilities, empirical antibiotic use is common. Unrecognized antibiotic resistance potentiates persistence of MRSA with osteomyelitis progression to chronic forms with complications despite antibiotic treatment. Materials and Methods: A prospective observational study was done to identify common etiological agent (s) in bone infection in Melanesian children (that were admitted to the two surgical and one pediatric wards of the SJNM-KUGH in the Simbu province of Papua New Guinea in 2012 and 2017), observe for presence of antimicrobial resistance, and determine effective antibiotic regimes for treatment of bone pediatric osteomyelitis. Seventy pediatric patients presenting from the community with osteomyelitis were recruited, with bone and non-bone specimens sampled, cultured and isolates tested for resistance to common antibiotics. Results: Staphylococcus aureus (S. aureus) was isolated in 67% (47/70) of collected specimens. Of the 47 isolates, there was 91.5% resistance to penicillin, 85.1% resistance to methicillin, 89.4% resistance to oxacillin, 93.6% resistance to ampicillin and 80.9% resistance to ceftriaxone. S. aureus showed 91.5% sensitivity to gentamycin, 93.6% sensitivity to erythromycin, tetracycline and clindamycin, and 95.7% sensitivity to Co-trimoxazole. Conclusion: MRSA was the leading cause of haematogenous osteomyelitis in Melanesian children. S.aureus was isolated mainly from infected long bones of the lower limbs (79%) of children presenting from the community, suggesting a predominantly community-associated MRSA.
The influence of probiotics on gastrointestinal tract infections among children attending childcare : a systematic review and meta-analysis
- Ahmad, Hafiz, Peck, Blake, Terry, Daniel
- Authors: Ahmad, Hafiz , Peck, Blake , Terry, Daniel
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Journal of Applied Microbiology Vol. 132, no. 3 (2022), p. 1636-1651
- Full Text:
- Reviewed:
- Description: Current literature related to the impact of probiotics on the incidence of gastrointestinal tract infections (GITIs) has shown mixed results and no systematic review available with pooled analysis exists. Thus, the aim of this systematic review was to provide contemporary evidence regarding the overall and strain-specific influence of probiotics in preventing GITIs among infants and children attending childcare centres. The review shortlisted 18 RCTs after screening through the initial search results of 779 articles. However, only 15 trials were deemed eligible, addressing at least one outcome in the pooled analysis. It is concluded that the supplementation of probiotics (overall effect) may reduce the risk of GITI episode by 26%, with Lacticaseibacillus paracasei, Limosilactobacillus reuteri and Lacticaseibacillus rhamnosus GG being specifically potent probiotic strains in reducing GITI episode, duration of infection and absence from childcare respectively. There is insufficient evidence to determine the effect of Bifidobacterium animalis subsp. lactis BB-12 based on the findings of the trials included in this review. © 2021 The Society for Applied Microbiology
- Authors: Ahmad, Hafiz , Peck, Blake , Terry, Daniel
- Date: 2022
- Type: Text , Journal article , Review
- Relation: Journal of Applied Microbiology Vol. 132, no. 3 (2022), p. 1636-1651
- Full Text:
- Reviewed:
- Description: Current literature related to the impact of probiotics on the incidence of gastrointestinal tract infections (GITIs) has shown mixed results and no systematic review available with pooled analysis exists. Thus, the aim of this systematic review was to provide contemporary evidence regarding the overall and strain-specific influence of probiotics in preventing GITIs among infants and children attending childcare centres. The review shortlisted 18 RCTs after screening through the initial search results of 779 articles. However, only 15 trials were deemed eligible, addressing at least one outcome in the pooled analysis. It is concluded that the supplementation of probiotics (overall effect) may reduce the risk of GITI episode by 26%, with Lacticaseibacillus paracasei, Limosilactobacillus reuteri and Lacticaseibacillus rhamnosus GG being specifically potent probiotic strains in reducing GITI episode, duration of infection and absence from childcare respectively. There is insufficient evidence to determine the effect of Bifidobacterium animalis subsp. lactis BB-12 based on the findings of the trials included in this review. © 2021 The Society for Applied Microbiology
Characterizing the role of vehicular cloud computing in road traffic management
- Ahmad, Iftikhar, Noor, Rafidah, Ali, Ihsan, Imran, Muhammad, Vasilakos, Athanasios
- Authors: Ahmad, Iftikhar , Noor, Rafidah , Ali, Ihsan , Imran, Muhammad , Vasilakos, Athanasios
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal of Distributed Sensor Networks Vol. 13, no. 5 (2017), p.
- Full Text:
- Reviewed:
- Description: Vehicular cloud computing is envisioned to deliver services that provide traffic safety and efficiency to vehicles. Vehicular cloud computing has great potential to change the contemporary vehicular communication paradigm. Explicitly, the underutilized resources of vehicles can be shared with other vehicles to manage traffic during congestion. These resources include but are not limited to storage, computing power, and Internet connectivity. This study reviews current traffic management systems to analyze the role and significance of vehicular cloud computing in road traffic management. First, an abstraction of the vehicular cloud infrastructure in an urban scenario is presented to explore the vehicular cloud computing process. A taxonomy of vehicular clouds that defines the cloud formation, integration types, and services is presented. A taxonomy of vehicular cloud services is also provided to explore the object types involved and their positions within the vehicular cloud. A comparison of the current state-of-the-art traffic management systems is performed in terms of parameters, such as vehicular ad hoc network infrastructure, Internet dependency, cloud management, scalability, traffic flow control, and emerging services. Potential future challenges and emerging technologies, such as the Internet of vehicles and its incorporation in traffic congestion control, are also discussed. Vehicular cloud computing is envisioned to have a substantial role in the development of smart traffic management solutions and in emerging Internet of vehicles. © The Author(s) 2017.
- Authors: Ahmad, Iftikhar , Noor, Rafidah , Ali, Ihsan , Imran, Muhammad , Vasilakos, Athanasios
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal of Distributed Sensor Networks Vol. 13, no. 5 (2017), p.
- Full Text:
- Reviewed:
- Description: Vehicular cloud computing is envisioned to deliver services that provide traffic safety and efficiency to vehicles. Vehicular cloud computing has great potential to change the contemporary vehicular communication paradigm. Explicitly, the underutilized resources of vehicles can be shared with other vehicles to manage traffic during congestion. These resources include but are not limited to storage, computing power, and Internet connectivity. This study reviews current traffic management systems to analyze the role and significance of vehicular cloud computing in road traffic management. First, an abstraction of the vehicular cloud infrastructure in an urban scenario is presented to explore the vehicular cloud computing process. A taxonomy of vehicular clouds that defines the cloud formation, integration types, and services is presented. A taxonomy of vehicular cloud services is also provided to explore the object types involved and their positions within the vehicular cloud. A comparison of the current state-of-the-art traffic management systems is performed in terms of parameters, such as vehicular ad hoc network infrastructure, Internet dependency, cloud management, scalability, traffic flow control, and emerging services. Potential future challenges and emerging technologies, such as the Internet of vehicles and its incorporation in traffic congestion control, are also discussed. Vehicular cloud computing is envisioned to have a substantial role in the development of smart traffic management solutions and in emerging Internet of vehicles. © The Author(s) 2017.
An efficient network intrusion detection and classification system
- Ahmad, Iftikhar, Haq, Qazi, Imran, Muhammad, Alassafi, Madini, Alghamdi, Rayed
- Authors: Ahmad, Iftikhar , Haq, Qazi , Imran, Muhammad , Alassafi, Madini , Alghamdi, Rayed
- Date: 2022
- Type: Text , Journal article
- Relation: Mathematics Vol. 10, no. 3 (2022), p.
- Full Text:
- Reviewed:
- Description: Intrusion detection in computer networks is of great importance because of its effects on the different communication and security domains. The detection of network intrusion is a challenge. Moreover, network intrusion detection remains a challenging task as a massive amount of data is required to train the state-of-the-art machine learning models to detect network intrusion threats. Many approaches have already been proposed recently on network intrusion detection. However, they face critical challenges owing to the continuous increase in new threats that current systems do not understand. This paper compares multiple techniques to develop a network intrusion detection system. Optimum features are selected from the dataset based on the correlation between the features. Furthermore, we propose an AdaBoost-based approach for network intrusion detection based on these selected features and present its detailed functionality and performance. Unlike most previous studies, which employ the KDD99 dataset, we used a recent and comprehensive UNSW-NB 15 dataset for network anomaly detection. This dataset is a collection of network packets exchanged between hosts. It comprises 49 attributes, including nine types of threats such as DoS, Fuzzers, Exploit, Worm, shellcode, reconnaissance, generic, and analysis Backdoor. In this study, we employ SVM and MLP for comparison. Finally, we propose AdaBoost based on the decision tree classifier to classify normal activity and possible threats. We monitored the network traffic and classified it into either threats or non-threats. The experimental findings showed that our proposed method effectively detects different forms of network intrusions on computer networks and achieves an accuracy of 99.3% on the UNSW-NB15 dataset. The proposed system will be helpful in network security applications and research domains. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
- Authors: Ahmad, Iftikhar , Haq, Qazi , Imran, Muhammad , Alassafi, Madini , Alghamdi, Rayed
- Date: 2022
- Type: Text , Journal article
- Relation: Mathematics Vol. 10, no. 3 (2022), p.
- Full Text:
- Reviewed:
- Description: Intrusion detection in computer networks is of great importance because of its effects on the different communication and security domains. The detection of network intrusion is a challenge. Moreover, network intrusion detection remains a challenging task as a massive amount of data is required to train the state-of-the-art machine learning models to detect network intrusion threats. Many approaches have already been proposed recently on network intrusion detection. However, they face critical challenges owing to the continuous increase in new threats that current systems do not understand. This paper compares multiple techniques to develop a network intrusion detection system. Optimum features are selected from the dataset based on the correlation between the features. Furthermore, we propose an AdaBoost-based approach for network intrusion detection based on these selected features and present its detailed functionality and performance. Unlike most previous studies, which employ the KDD99 dataset, we used a recent and comprehensive UNSW-NB 15 dataset for network anomaly detection. This dataset is a collection of network packets exchanged between hosts. It comprises 49 attributes, including nine types of threats such as DoS, Fuzzers, Exploit, Worm, shellcode, reconnaissance, generic, and analysis Backdoor. In this study, we employ SVM and MLP for comparison. Finally, we propose AdaBoost based on the decision tree classifier to classify normal activity and possible threats. We monitored the network traffic and classified it into either threats or non-threats. The experimental findings showed that our proposed method effectively detects different forms of network intrusions on computer networks and achieves an accuracy of 99.3% on the UNSW-NB15 dataset. The proposed system will be helpful in network security applications and research domains. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.
An optimized hybrid deep intrusion detection model (HD-IDM) for enhancing network security
- Ahmad, Iftikhar, Imran, Muhammad, Qayyum, Abdul, Ramzan, Muhammad, Alassafi, Madini
- Authors: Ahmad, Iftikhar , Imran, Muhammad , Qayyum, Abdul , Ramzan, Muhammad , Alassafi, Madini
- Date: 2023
- Type: Text , Journal article
- Relation: Mathematics Vol. 11, no. 21 (2023), p.
- Full Text:
- Reviewed:
- Description: Detecting cyber intrusions in network traffic is a tough task for cybersecurity. Current methods struggle with the complexity of understanding patterns in network data. To solve this, we present the Hybrid Deep Learning Intrusion Detection Model (HD-IDM), a new way that combines GRU and LSTM classifiers. GRU is good at catching quick patterns, while LSTM handles long-term ones. HD-IDM blends these models using weighted averaging, boosting accuracy, especially with complex patterns. We tested HD-IDM on four datasets: CSE-CIC-IDS2017, CSE-CIC-IDS2018, NSL KDD, and CIC-DDoS2019. The HD-IDM classifier achieved remarkable performance metrics on all datasets. It attains an outstanding accuracy of 99.91%, showcasing its consistent precision across the dataset. With an impressive precision of 99.62%, it excels in accurately categorizing positive cases, crucial for minimizing false positives. Additionally, maintaining a high recall of 99.43%, it effectively identifies the majority of actual positive cases while minimizing false negatives. The F1-score of 99.52% emphasizes its robustness, making it the top choice for classification tasks requiring precision and reliability. It is particularly good at ROC and precision/recall curves, discriminating normal and harmful network activities. While HD-IDM is promising, it has limits. It needs labeled data and may struggle with new intrusion methods. Future work should find ways to handle unlabeled data and adapt to emerging threats. Also, making HD-IDM work faster for real-time use and dealing with scalability challenges is key for its broader use in changing network environments. © 2023 by the authors.
- Authors: Ahmad, Iftikhar , Imran, Muhammad , Qayyum, Abdul , Ramzan, Muhammad , Alassafi, Madini
- Date: 2023
- Type: Text , Journal article
- Relation: Mathematics Vol. 11, no. 21 (2023), p.
- Full Text:
- Reviewed:
- Description: Detecting cyber intrusions in network traffic is a tough task for cybersecurity. Current methods struggle with the complexity of understanding patterns in network data. To solve this, we present the Hybrid Deep Learning Intrusion Detection Model (HD-IDM), a new way that combines GRU and LSTM classifiers. GRU is good at catching quick patterns, while LSTM handles long-term ones. HD-IDM blends these models using weighted averaging, boosting accuracy, especially with complex patterns. We tested HD-IDM on four datasets: CSE-CIC-IDS2017, CSE-CIC-IDS2018, NSL KDD, and CIC-DDoS2019. The HD-IDM classifier achieved remarkable performance metrics on all datasets. It attains an outstanding accuracy of 99.91%, showcasing its consistent precision across the dataset. With an impressive precision of 99.62%, it excels in accurately categorizing positive cases, crucial for minimizing false positives. Additionally, maintaining a high recall of 99.43%, it effectively identifies the majority of actual positive cases while minimizing false negatives. The F1-score of 99.52% emphasizes its robustness, making it the top choice for classification tasks requiring precision and reliability. It is particularly good at ROC and precision/recall curves, discriminating normal and harmful network activities. While HD-IDM is promising, it has limits. It needs labeled data and may struggle with new intrusion methods. Future work should find ways to handle unlabeled data and adapt to emerging threats. Also, making HD-IDM work faster for real-time use and dealing with scalability challenges is key for its broader use in changing network environments. © 2023 by the authors.
Process performance evaluation using evolutionary algorithm
- Ahmad, S., Huda, Shamsul, Bakir, S., Abdollahian, Mali, Zeephongsekul, P.
- Authors: Ahmad, S. , Huda, Shamsul , Bakir, S. , Abdollahian, Mali , Zeephongsekul, P.
- Date: 2009
- Type: Text , Conference paper
- Relation: Paper presented at 2009 International Conference on Information & Knowledge Engineering, IKE 2009, Las Vegas, Nevada, U.S.A. : 13th-16th July 2009 p. 731-737
- Full Text:
- Description: Nowadays every business is using different quantitative measures and techniques to assess performance of their products / services. It is well known that different manufacturing processes very often manufacture products with quality characteristics that do not follow normal distribution. In such cases, fitting a known non-normal distribution to these quality characteristics would lead to erroneous results. Furthermore, there is always more than one characteristic Critical to Quality (CTQ) in the process outcomes and very often these quality characteristics are correlated with each other. In this paper, we assess performance of such a bivariate process data which is non-normal as well as correlated. We will use the geometric distance approach to reduce the dimension of the correlated non-normal bivariate data and then fit Burr distribution to the geometric distance variable. The optimal parameters of the fitted Burr distribution are estimated using Evolutionary Algorithm (EA). The results are compared with those using Simulated Annealing (SA) algorithm. The proportion of nonconformance (PNC) for process measurements is then obtained by using the fitted Burr distributions based on the two methods. The results based on both search algorithms are then compared with the exact proportion of nonconformance of the data. Finally, a case study using real data is presented.
- Description: 2003008140
- Authors: Ahmad, S. , Huda, Shamsul , Bakir, S. , Abdollahian, Mali , Zeephongsekul, P.
- Date: 2009
- Type: Text , Conference paper
- Relation: Paper presented at 2009 International Conference on Information & Knowledge Engineering, IKE 2009, Las Vegas, Nevada, U.S.A. : 13th-16th July 2009 p. 731-737
- Full Text:
- Description: Nowadays every business is using different quantitative measures and techniques to assess performance of their products / services. It is well known that different manufacturing processes very often manufacture products with quality characteristics that do not follow normal distribution. In such cases, fitting a known non-normal distribution to these quality characteristics would lead to erroneous results. Furthermore, there is always more than one characteristic Critical to Quality (CTQ) in the process outcomes and very often these quality characteristics are correlated with each other. In this paper, we assess performance of such a bivariate process data which is non-normal as well as correlated. We will use the geometric distance approach to reduce the dimension of the correlated non-normal bivariate data and then fit Burr distribution to the geometric distance variable. The optimal parameters of the fitted Burr distribution are estimated using Evolutionary Algorithm (EA). The results are compared with those using Simulated Annealing (SA) algorithm. The proportion of nonconformance (PNC) for process measurements is then obtained by using the fitted Burr distributions based on the two methods. The results based on both search algorithms are then compared with the exact proportion of nonconformance of the data. Finally, a case study using real data is presented.
- Description: 2003008140
Development of a unified railway track stability management tool to enhance track safety
- Ahmad, Shah, Mandal, Nirmal, Chattopadhyay, Gopinath, Powell, John
- Authors: Ahmad, Shah , Mandal, Nirmal , Chattopadhyay, Gopinath , Powell, John
- Date: 2013
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit Vol. 227, no. 5 (2013), p. 493-516
- Full Text:
- Reviewed:
- Description: Track buckling is a serious problem for railways. High longitudinal rail stresses contribute to problems such as track buckling, rail joint failure, rail breakage and failure of turnouts. The direct and indirect costs of track buckling problems are very high. The influences of rail temperature, stress-free temperature (SFT) and lateral misalignment of track on track buckling need comprehensive investigation. In this paper, an experimental design comprising strain gauges, thermocouples and rail stress sensors has been implemented on the Queensland Rail heavy haul 60 kg/m rail network. A new creep measurement technique using internal rail stress has been developed. The changes in rail neutral temperature due to the variation of actual rail temperature and the occurrence of rail creep in straight and curved track is quantified. Modes of differences of SFT in the two rails at a location, and of SFT in straight track and in curved track are discussed. The relationship of SFT to rail temperature is also presented. Daily variation in rail temperature due to ambient air temperature is presented. Field trials showed that SFT can vary by 2-3 °C during the day. Based on this finding and the derivation of an equation for change of SFT, an improvement in utilising rail creep measurements for assessing track condition has resulted. This finding suggests that it is possible to determine the SFT throughout a day rather than just a single SFT value. This paper also presents a simple track stability management tool that is based on two major parameters, namely rail stress and track resistance. Each parameter in the tool has been given three levels of value to determine the required preventive measures. Overall, the tool decides the need for speed restriction during hot weather based on the quantified parameters from the field trials and rail standards. © IMechE 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
- Authors: Ahmad, Shah , Mandal, Nirmal , Chattopadhyay, Gopinath , Powell, John
- Date: 2013
- Type: Text , Journal article
- Relation: Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit Vol. 227, no. 5 (2013), p. 493-516
- Full Text:
- Reviewed:
- Description: Track buckling is a serious problem for railways. High longitudinal rail stresses contribute to problems such as track buckling, rail joint failure, rail breakage and failure of turnouts. The direct and indirect costs of track buckling problems are very high. The influences of rail temperature, stress-free temperature (SFT) and lateral misalignment of track on track buckling need comprehensive investigation. In this paper, an experimental design comprising strain gauges, thermocouples and rail stress sensors has been implemented on the Queensland Rail heavy haul 60 kg/m rail network. A new creep measurement technique using internal rail stress has been developed. The changes in rail neutral temperature due to the variation of actual rail temperature and the occurrence of rail creep in straight and curved track is quantified. Modes of differences of SFT in the two rails at a location, and of SFT in straight track and in curved track are discussed. The relationship of SFT to rail temperature is also presented. Daily variation in rail temperature due to ambient air temperature is presented. Field trials showed that SFT can vary by 2-3 °C during the day. Based on this finding and the derivation of an equation for change of SFT, an improvement in utilising rail creep measurements for assessing track condition has resulted. This finding suggests that it is possible to determine the SFT throughout a day rather than just a single SFT value. This paper also presents a simple track stability management tool that is based on two major parameters, namely rail stress and track resistance. Each parameter in the tool has been given three levels of value to determine the required preventive measures. Overall, the tool decides the need for speed restriction during hot weather based on the quantified parameters from the field trials and rail standards. © IMechE 2013 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
The role of immune cells in ovarian cancer
- Authors: Ahmady, Farah
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Ovarian cancer remains the leading cause of gynaecological disease related death in women worldwide. Patients given standard treatment have low survival rates and immunotherapy remains unsuccessful. This is largely due to the suppressive tumour microenvironment (TME) and the interaction of the different cells being poorly understood. This has sparked interest in understanding the functions of immune cells and their contribution to the TME. In chapter 3, B and T cells were characterised in samples collected from chemo-naïve highgrade serous ovarian cancer (HGSOC) patients and compared to benign and healthy controls. B cells were able to express the T cell exhaustion marker T cell immunoglobulin and mucin domain-3 (TIM-3) on their surface. Blood derived B cells of benign patients expressed less TIM-3 compared to high-grade and healthy donors. Alterations in TIM-3 expression on B cells suggests that the TME may not be causing B cells to harbour an exhaustion phenotype. The frequency of circulating mucosal-associated invariant T cells (MAIT cells) was reduced in benign and high-grade patients compared to healthy donors. Blood derived MAIT cells of healthy donors stimulated with 5-OP-RU antigen and cultured with ovarian cancer cell line supernatants had a reduced capacity of producing tumour necrosis factor (TNF)-a compared to control. The reduced frequency of MAIT cells at the premalignant state of the disease indicates that malignancy of the disease is not necessarily the contributing factor in the reduction observed. As TNF-a is a key anti-tumour cytokine expressed by MAIT cells, the impaired production may indicate defects in their function. Low dose-dense (LDD) chemotherapy has recently shown promise as depicted in a clinical study by Kannourakis et al. where LDD treated HGSOC patients had longer survival than those treated with maximum tolerated dose (MTD). It is postulated that this may be due to aspects of the immune system, however the effects of LDD chemotherapy on immune cells remains unknown. In chpter 4, circulating B and T cells of LDD treated patients were characterised and compared to untreated controls. The key finding of this study was the immunostimulatory attributes of LDD regimen in a range of B and T cell populations via their increased expression of TNF-a compared to untreated controls and healthy donors. The frequency of MAIT cells, however, was reduced in LDD treated patients, suggesting that these cells may not contribute to the immunostimulatory aspects, and that this regimen may impact their frequency by creating an environment which may not be compatible for MAIT cell survival. In chapter 5, expression of immuno-oncology protein markers in benign and high-grade primary and metastasised tumours were determined for alterations in hot and cold tumour regions using Digital Spatial Profiling (DSP). An increased expression of immune cell, costimulatory and inhibitory markers were apparent in high-grade tumours compared to benign. The stimulator of interferon genes (STING) marker was studied further, and its expression was also higher in high-grade tumours compared to benign, with cisplatin further enhancing its expression in ovarian cancer cell lines. There were alterations in the expression of some downstream molecules, however interferon (IFN)-b, the key cytokine produced in the activated STING pathway, was virtually non-existent. This suggests a defect in the pathway which if restored, may contribute to some of the known anti-tumour functions of the pathway. The results from these studies provide an understanding of differences in the immune profile of non-malignant and malignant ovarian cancer. These findings work together to improve our understanding of the unique TME with the aim to identify potential immune therapeutic targets for future study.
- Description: Doctor of Philosophy
- Authors: Ahmady, Farah
- Date: 2022
- Type: Text , Thesis , PhD
- Full Text:
- Description: Ovarian cancer remains the leading cause of gynaecological disease related death in women worldwide. Patients given standard treatment have low survival rates and immunotherapy remains unsuccessful. This is largely due to the suppressive tumour microenvironment (TME) and the interaction of the different cells being poorly understood. This has sparked interest in understanding the functions of immune cells and their contribution to the TME. In chapter 3, B and T cells were characterised in samples collected from chemo-naïve highgrade serous ovarian cancer (HGSOC) patients and compared to benign and healthy controls. B cells were able to express the T cell exhaustion marker T cell immunoglobulin and mucin domain-3 (TIM-3) on their surface. Blood derived B cells of benign patients expressed less TIM-3 compared to high-grade and healthy donors. Alterations in TIM-3 expression on B cells suggests that the TME may not be causing B cells to harbour an exhaustion phenotype. The frequency of circulating mucosal-associated invariant T cells (MAIT cells) was reduced in benign and high-grade patients compared to healthy donors. Blood derived MAIT cells of healthy donors stimulated with 5-OP-RU antigen and cultured with ovarian cancer cell line supernatants had a reduced capacity of producing tumour necrosis factor (TNF)-a compared to control. The reduced frequency of MAIT cells at the premalignant state of the disease indicates that malignancy of the disease is not necessarily the contributing factor in the reduction observed. As TNF-a is a key anti-tumour cytokine expressed by MAIT cells, the impaired production may indicate defects in their function. Low dose-dense (LDD) chemotherapy has recently shown promise as depicted in a clinical study by Kannourakis et al. where LDD treated HGSOC patients had longer survival than those treated with maximum tolerated dose (MTD). It is postulated that this may be due to aspects of the immune system, however the effects of LDD chemotherapy on immune cells remains unknown. In chpter 4, circulating B and T cells of LDD treated patients were characterised and compared to untreated controls. The key finding of this study was the immunostimulatory attributes of LDD regimen in a range of B and T cell populations via their increased expression of TNF-a compared to untreated controls and healthy donors. The frequency of MAIT cells, however, was reduced in LDD treated patients, suggesting that these cells may not contribute to the immunostimulatory aspects, and that this regimen may impact their frequency by creating an environment which may not be compatible for MAIT cell survival. In chapter 5, expression of immuno-oncology protein markers in benign and high-grade primary and metastasised tumours were determined for alterations in hot and cold tumour regions using Digital Spatial Profiling (DSP). An increased expression of immune cell, costimulatory and inhibitory markers were apparent in high-grade tumours compared to benign. The stimulator of interferon genes (STING) marker was studied further, and its expression was also higher in high-grade tumours compared to benign, with cisplatin further enhancing its expression in ovarian cancer cell lines. There were alterations in the expression of some downstream molecules, however interferon (IFN)-b, the key cytokine produced in the activated STING pathway, was virtually non-existent. This suggests a defect in the pathway which if restored, may contribute to some of the known anti-tumour functions of the pathway. The results from these studies provide an understanding of differences in the immune profile of non-malignant and malignant ovarian cancer. These findings work together to improve our understanding of the unique TME with the aim to identify potential immune therapeutic targets for future study.
- Description: Doctor of Philosophy
Risky drinking social worlds in Victoria: a social media analysis
- Ahmed, Ashir, Martin, Jennifer, Towl, David, Haussegger, Zac
- Authors: Ahmed, Ashir , Martin, Jennifer , Towl, David , Haussegger, Zac
- Date: 2021
- Type: Text , Technical report , Report
- Full Text:
- Authors: Ahmed, Ashir , Martin, Jennifer , Towl, David , Haussegger, Zac
- Date: 2021
- Type: Text , Technical report , Report
- Full Text:
A novel collaborative IoD-assisted VANET approach for coverage area maximization
- Ahmed, Gamil, Sheltami, Tarek, Mahmoud, Ashraf, Imran, Muhammad, Shoaib, Muhammad
- Authors: Ahmed, Gamil , Sheltami, Tarek , Mahmoud, Ashraf , Imran, Muhammad , Shoaib, Muhammad
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Access Vol. 9, no. (2021), p. 61211-61223
- Full Text:
- Reviewed:
- Description: Internet of Drones (IoD) is an efficient technique that can be integrated with vehicular ad-hoc networks (VANETs) to provide terrestrial communications by acting as an aerial relay when terrestrial infrastructure is unreliable or unavailable. To fully exploit the drones' flexibility and superiority, we propose a novel dynamic IoD collaborative communication approach for urban VANETs. Unlike most of the existing approaches, the IoD nodes are dynamically deployed based on current locations of ground vehicles to effectively mitigate inevitable isolated cars in conventional VANETs. For efficiently coordinating IoD, we model IoD to optimize coverage based on the location of vehicles. The goal is to obtain an efficient IoD deployment to maximize the number of covered vehicles, i.e., minimize the number of isolated vehicles in the target area. More importantly, the proposed approach provides sufficient interconnections between IoD nodes. To do so, an improved version of succinct population-based meta-heuristic, namely Improved Particle Swarm Optimization (IPSO) inspired by food searching behavior of birds or fishes flock, is implemented for IoD assisted VANET (IoDAV). Moreover, the coverage, received signal quality, and IoD connectivity are achieved by IPSO's objective function for optimal IoD deployment at the same time. We carry out an extensive experiment based on the received signal at floating vehicles to examine the proposed IoDAV performance. We compare the results with the baseline VANET with no IoD (NIoD) and Fixed IoD assisted (FIoD). The comparisons are based on the coverage percentage of the ground vehicles and the quality of the received signal. The simulation results demonstrate that the proposed IoDAV approach allows finding the optimal IoD positions throughout the time based on the vehicle's movements and achieves better coverage and better quality of the received signal by finding the most appropriate IoD position compared with NIoD and FIoD schemes. © 2013 IEEE.
- Authors: Ahmed, Gamil , Sheltami, Tarek , Mahmoud, Ashraf , Imran, Muhammad , Shoaib, Muhammad
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Access Vol. 9, no. (2021), p. 61211-61223
- Full Text:
- Reviewed:
- Description: Internet of Drones (IoD) is an efficient technique that can be integrated with vehicular ad-hoc networks (VANETs) to provide terrestrial communications by acting as an aerial relay when terrestrial infrastructure is unreliable or unavailable. To fully exploit the drones' flexibility and superiority, we propose a novel dynamic IoD collaborative communication approach for urban VANETs. Unlike most of the existing approaches, the IoD nodes are dynamically deployed based on current locations of ground vehicles to effectively mitigate inevitable isolated cars in conventional VANETs. For efficiently coordinating IoD, we model IoD to optimize coverage based on the location of vehicles. The goal is to obtain an efficient IoD deployment to maximize the number of covered vehicles, i.e., minimize the number of isolated vehicles in the target area. More importantly, the proposed approach provides sufficient interconnections between IoD nodes. To do so, an improved version of succinct population-based meta-heuristic, namely Improved Particle Swarm Optimization (IPSO) inspired by food searching behavior of birds or fishes flock, is implemented for IoD assisted VANET (IoDAV). Moreover, the coverage, received signal quality, and IoD connectivity are achieved by IPSO's objective function for optimal IoD deployment at the same time. We carry out an extensive experiment based on the received signal at floating vehicles to examine the proposed IoDAV performance. We compare the results with the baseline VANET with no IoD (NIoD) and Fixed IoD assisted (FIoD). The comparisons are based on the coverage percentage of the ground vehicles and the quality of the received signal. The simulation results demonstrate that the proposed IoDAV approach allows finding the optimal IoD positions throughout the time based on the vehicle's movements and achieves better coverage and better quality of the received signal by finding the most appropriate IoD position compared with NIoD and FIoD schemes. © 2013 IEEE.
Tumour microenvironment and metabolic plasticity in cancer and cancer stem cells : Perspectives on metabolic and immune regulatory signatures in chemoresistant ovarian cancer stem cells
- Ahmed, Nuzhat, Escalona, Ruth, Leung, Dilys, Chan, Emily, Kannourakis, George
- Authors: Ahmed, Nuzhat , Escalona, Ruth , Leung, Dilys , Chan, Emily , Kannourakis, George
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Seminars in Cancer Biology Vol. 53, no. (2018), p. 265-281
- Full Text:
- Reviewed:
- Description: Cancer stem cells (CSCs) are a sub-population of tumour cells, which are responsible to drive tumour growth, metastasis and therapy resistance. It has recently been proposed that enhanced glucose metabolism and immune evasion by tumour cells are linked, and are modulated by the changing tumour microenvironment (TME) that creates a competition for nutrient consumption between tumour and different sub-types of cells attracted to the TME. To facilitate efficient nutrient distribution, oncogene-induced inflammatory milieu in the tumours facilitate adaptive metabolic changes in the surrounding non-malignant cells to secrete metabolites that are used as alternative nutrient sources by the tumours to sustain its increasing energy needs for growth and anabolic functions. This scenario also affects CSCs residing at the primary or metastatic niches. This review summarises recent advances in our understanding of the metabolic phenotypes of cancer cells and CSCs and how these processes are affected by the TME. We also discuss how the evolving TME modulates tumour cells and CSCs in cancer progression. Using previously described proteomic and genomic platforms, ovarian cancer cell lines and a mouse xenograft model we highlight the existence of metabolic and immune regulatory signatures in chemoresistant ovarian CSCs, and discuss how these processes may affect recurrence in ovarian tumours. We propose that progress in cancer control and eradication may depend not only on the elimination of highly chemoresistant CSCs, but also in designing novel strategies which would intervene with the tumour-promoting TME factors.
- Authors: Ahmed, Nuzhat , Escalona, Ruth , Leung, Dilys , Chan, Emily , Kannourakis, George
- Date: 2018
- Type: Text , Journal article , Review
- Relation: Seminars in Cancer Biology Vol. 53, no. (2018), p. 265-281
- Full Text:
- Reviewed:
- Description: Cancer stem cells (CSCs) are a sub-population of tumour cells, which are responsible to drive tumour growth, metastasis and therapy resistance. It has recently been proposed that enhanced glucose metabolism and immune evasion by tumour cells are linked, and are modulated by the changing tumour microenvironment (TME) that creates a competition for nutrient consumption between tumour and different sub-types of cells attracted to the TME. To facilitate efficient nutrient distribution, oncogene-induced inflammatory milieu in the tumours facilitate adaptive metabolic changes in the surrounding non-malignant cells to secrete metabolites that are used as alternative nutrient sources by the tumours to sustain its increasing energy needs for growth and anabolic functions. This scenario also affects CSCs residing at the primary or metastatic niches. This review summarises recent advances in our understanding of the metabolic phenotypes of cancer cells and CSCs and how these processes are affected by the TME. We also discuss how the evolving TME modulates tumour cells and CSCs in cancer progression. Using previously described proteomic and genomic platforms, ovarian cancer cell lines and a mouse xenograft model we highlight the existence of metabolic and immune regulatory signatures in chemoresistant ovarian CSCs, and discuss how these processes may affect recurrence in ovarian tumours. We propose that progress in cancer control and eradication may depend not only on the elimination of highly chemoresistant CSCs, but also in designing novel strategies which would intervene with the tumour-promoting TME factors.
Unique proteome signature of post-chemotherapy ovarian cancer ascites-derived tumor cells
- Ahmed, Nuzhat, Greening, David, Samardzija, Chantel, Escalona, Ruth, Chen, Maoshan, Findlay, Jock, Kannourakis, George
- Authors: Ahmed, Nuzhat , Greening, David , Samardzija, Chantel , Escalona, Ruth , Chen, Maoshan , Findlay, Jock , Kannourakis, George
- Date: 2016
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 6, no. (2016), p. 1-13
- Full Text:
- Reviewed:
- Description: Eighty % of ovarian cancer patients diagnosed at an advanced-stage have complete remission after initial surgery and chemotherapy. However, most patients die within <5 years due to episodes of recurrences resulting from the growth of residual chemoresistant cells. In an effort to identify mechanisms associated with chemoresistance and recurrence, we compared the expression of proteins in ascites-derived tumor cells isolated from advanced-stage ovarian cancer patients obtained at diagnosis (chemonaive, CN) and after chemotherapy treatments (chemoresistant/at recurrence, CR) by using in-depth, high-resolution label-free quantitative proteomic profiling. A total of 2,999 proteins were identified. Using a stringent selection criterion to define only significantly differentially expressed proteins, we report identification of 353 proteins. There were significant differences in proteins encoding for immune surveillance, DNA repair mechanisms, cytoskeleton rearrangement, cell-cell adhesion, cell cycle pathways, cellular transport, and proteins involved with glycine/proline/arginine synthesis in tumor cells isolated from CR relative to CN patients. Pathway analyses revealed enrichment of metabolic pathways, DNA repair mechanisms and energy metabolism pathways in CR tumor cells. In conclusion, this is the first proteomics study to comprehensively analyze ascites-derived tumor cells from CN and CR ovarian cancer patients.
- Authors: Ahmed, Nuzhat , Greening, David , Samardzija, Chantel , Escalona, Ruth , Chen, Maoshan , Findlay, Jock , Kannourakis, George
- Date: 2016
- Type: Text , Journal article
- Relation: Scientific Reports Vol. 6, no. (2016), p. 1-13
- Full Text:
- Reviewed:
- Description: Eighty % of ovarian cancer patients diagnosed at an advanced-stage have complete remission after initial surgery and chemotherapy. However, most patients die within <5 years due to episodes of recurrences resulting from the growth of residual chemoresistant cells. In an effort to identify mechanisms associated with chemoresistance and recurrence, we compared the expression of proteins in ascites-derived tumor cells isolated from advanced-stage ovarian cancer patients obtained at diagnosis (chemonaive, CN) and after chemotherapy treatments (chemoresistant/at recurrence, CR) by using in-depth, high-resolution label-free quantitative proteomic profiling. A total of 2,999 proteins were identified. Using a stringent selection criterion to define only significantly differentially expressed proteins, we report identification of 353 proteins. There were significant differences in proteins encoding for immune surveillance, DNA repair mechanisms, cytoskeleton rearrangement, cell-cell adhesion, cell cycle pathways, cellular transport, and proteins involved with glycine/proline/arginine synthesis in tumor cells isolated from CR relative to CN patients. Pathway analyses revealed enrichment of metabolic pathways, DNA repair mechanisms and energy metabolism pathways in CR tumor cells. In conclusion, this is the first proteomics study to comprehensively analyze ascites-derived tumor cells from CN and CR ovarian cancer patients.
Ovarian cancer, cancer stem cells and current treatment strategies : a potential role of magmas in the current treatment methods
- Ahmed, Nuzhat, Kadife, Elif, Raza, Ali, Short, Mary, Jubinsky, Paul, Kannourakis, George
- Authors: Ahmed, Nuzhat , Kadife, Elif , Raza, Ali , Short, Mary , Jubinsky, Paul , Kannourakis, George
- Date: 2020
- Type: Text , Journal article , Review
- Relation: Cells Vol. 9, no. 3 (Mar 2020), p. 35
- Full Text:
- Reviewed:
- Description: Epithelial ovarian cancer (EOC) constitutes 90% of ovarian cancers (OC) and is the eighth most common cause of cancer-related death in women. The cancer histologically and genetically is very complex having a high degree of tumour heterogeneity. The pathogenic variability in OC causes significant impediments in effectively treating patients, resulting in a dismal prognosis. Disease progression is predominantly influenced by the peritoneal tumour microenvironment rather than properties of the tumor and is the major contributor to prognosis. Standard treatment of OC patients consists of debulking surgery, followed by chemotherapy, which in most cases end in recurrent chemoresistant disease. This review discusses the different origins of high-grade serous ovarian cancer (HGSOC), the major sub-type of EOC. Tumour heterogeneity, genetic/epigenetic changes, and cancer stem cells (CSC) in facilitating HGSOC progression and their contribution in the circumvention of therapy treatments are included. Several new treatment strategies are discussed including our preliminary proof of concept study describing the role of mitochondria-associated granulocyte macrophage colony-stimulating factor signaling protein (Magmas) in HGSOC and its unique potential role in chemotherapy-resistant disease.
- Authors: Ahmed, Nuzhat , Kadife, Elif , Raza, Ali , Short, Mary , Jubinsky, Paul , Kannourakis, George
- Date: 2020
- Type: Text , Journal article , Review
- Relation: Cells Vol. 9, no. 3 (Mar 2020), p. 35
- Full Text:
- Reviewed:
- Description: Epithelial ovarian cancer (EOC) constitutes 90% of ovarian cancers (OC) and is the eighth most common cause of cancer-related death in women. The cancer histologically and genetically is very complex having a high degree of tumour heterogeneity. The pathogenic variability in OC causes significant impediments in effectively treating patients, resulting in a dismal prognosis. Disease progression is predominantly influenced by the peritoneal tumour microenvironment rather than properties of the tumor and is the major contributor to prognosis. Standard treatment of OC patients consists of debulking surgery, followed by chemotherapy, which in most cases end in recurrent chemoresistant disease. This review discusses the different origins of high-grade serous ovarian cancer (HGSOC), the major sub-type of EOC. Tumour heterogeneity, genetic/epigenetic changes, and cancer stem cells (CSC) in facilitating HGSOC progression and their contribution in the circumvention of therapy treatments are included. Several new treatment strategies are discussed including our preliminary proof of concept study describing the role of mitochondria-associated granulocyte macrophage colony-stimulating factor signaling protein (Magmas) in HGSOC and its unique potential role in chemotherapy-resistant disease.
A coarse representation of frames oriented video coding by leveraging cuboidal partitioning of image data
- Ahmmed, Ashe, Paul, Manoranjan, Murshed, Manzur, Taubman, David
- Authors: Ahmmed, Ashe , Paul, Manoranjan , Murshed, Manzur , Taubman, David
- Date: 2020
- Type: Text , Conference paper
- Relation: 22nd IEEE International Workshop on Multimedia Signal Processing, MMSP 2020, Virtual Tampere, Finland 21-24 September 2020
- Full Text:
- Reviewed:
- Description: Video coding algorithms attempt to minimize the significant commonality that exists within a video sequence. Each new video coding standard contains tools that can perform this task more efficiently compared to its predecessors. In this work, we form a coarse representation of the current frame by minimizing commonality within that frame while preserving important structural properties of the frame. The building blocks of this coarse representation are rectangular regions called cuboids, which are computationally simple and has a compact description. Then we propose to employ the coarse frame as an additional source for predictive coding of the current frame. Experimental results show an improvement in bit rate savings over a reference codec for HEVC, with minor increase in the codec computational complexity. © 2020 IEEE.
- Authors: Ahmmed, Ashe , Paul, Manoranjan , Murshed, Manzur , Taubman, David
- Date: 2020
- Type: Text , Conference paper
- Relation: 22nd IEEE International Workshop on Multimedia Signal Processing, MMSP 2020, Virtual Tampere, Finland 21-24 September 2020
- Full Text:
- Reviewed:
- Description: Video coding algorithms attempt to minimize the significant commonality that exists within a video sequence. Each new video coding standard contains tools that can perform this task more efficiently compared to its predecessors. In this work, we form a coarse representation of the current frame by minimizing commonality within that frame while preserving important structural properties of the frame. The building blocks of this coarse representation are rectangular regions called cuboids, which are computationally simple and has a compact description. Then we propose to employ the coarse frame as an additional source for predictive coding of the current frame. Experimental results show an improvement in bit rate savings over a reference codec for HEVC, with minor increase in the codec computational complexity. © 2020 IEEE.
Human-machine collaborative video coding through cuboidal partitioning
- Ahmmed, Ashek, Paul, Manoranjan, Murshed, Manzur, Taubman, David
- Authors: Ahmmed, Ashek , Paul, Manoranjan , Murshed, Manzur , Taubman, David
- Date: 2021
- Type: Text , Conference paper
- Relation: 2021 IEEE International Conference on Image Processing, ICIP 2021, Anchorage, USA 19-22 September 2021, Proceedings - International Conference on Image Processing, ICIP Vol. 2021-September, p. 2074-2078
- Full Text:
- Reviewed:
- Description: Video coding algorithms encode and decode an entire video frame while feature coding techniques only preserve and communicate the most critical information needed for a given application. This is because video coding targets human perception, while feature coding aims for machine vision tasks. Recently, attempts are being made to bridge the gap between these two domains. In this work, we propose a video coding framework by leveraging on to the commonality that exists between human vision and machine vision applications using cuboids. This is because cuboids, estimated rectangular regions over a video frame, are computationally efficient, has a compact representation and object centric. Such properties are already shown to add value to traditional video coding systems. Herein cuboidal feature descriptors are extracted from the current frame and then employed for accomplishing a machine vision task in the form of object detection. Experimental results show that a trained classifier yields superior average precision when equipped with cuboidal features oriented representation of the current test frame. Additionally, this representation costs 7% less in bit rate if the captured frames are need be communicated to a receiver. © 2021 IEEE.
- Authors: Ahmmed, Ashek , Paul, Manoranjan , Murshed, Manzur , Taubman, David
- Date: 2021
- Type: Text , Conference paper
- Relation: 2021 IEEE International Conference on Image Processing, ICIP 2021, Anchorage, USA 19-22 September 2021, Proceedings - International Conference on Image Processing, ICIP Vol. 2021-September, p. 2074-2078
- Full Text:
- Reviewed:
- Description: Video coding algorithms encode and decode an entire video frame while feature coding techniques only preserve and communicate the most critical information needed for a given application. This is because video coding targets human perception, while feature coding aims for machine vision tasks. Recently, attempts are being made to bridge the gap between these two domains. In this work, we propose a video coding framework by leveraging on to the commonality that exists between human vision and machine vision applications using cuboids. This is because cuboids, estimated rectangular regions over a video frame, are computationally efficient, has a compact representation and object centric. Such properties are already shown to add value to traditional video coding systems. Herein cuboidal feature descriptors are extracted from the current frame and then employed for accomplishing a machine vision task in the form of object detection. Experimental results show that a trained classifier yields superior average precision when equipped with cuboidal features oriented representation of the current test frame. Additionally, this representation costs 7% less in bit rate if the captured frames are need be communicated to a receiver. © 2021 IEEE.
Limited impact of neonatal or early infant schedules of 7-valent pneumococcal conjugate vaccination on nasopharyngeal carriage of Streptococcus pneumoniae in Papua New Guinean children: A randomized controlled trial
- Aho, Celestine, Michael, Audrey, Yoannes, Mition, Greenhill, Andrew, Jacoby, Peter, Reeder, John, Pomat, William, Saleu, Gerard, Namuigi, Pioto, Phuanukoonnon, Suparat, Smith-Vaughan, Heidi, Leach, Amanda, Richmond, Peter, Lehmann, Deborah
- Authors: Aho, Celestine , Michael, Audrey , Yoannes, Mition , Greenhill, Andrew , Jacoby, Peter , Reeder, John , Pomat, William , Saleu, Gerard , Namuigi, Pioto , Phuanukoonnon, Suparat , Smith-Vaughan, Heidi , Leach, Amanda , Richmond, Peter , Lehmann, Deborah
- Date: 2016
- Type: Text , Journal article
- Relation: Vaccine Reports Vol. 6, no. (2016), p. 36-43
- Full Text:
- Reviewed:
- Description: Streptococcus pneumoniae is a leading cause of pneumonia, the most common cause of childhood death. Papua New Guinean children experience high rates of nasopharyngeal pneumococcal colonization within weeks of birth, predisposing them to pneumococcal disease. In a trial to determine the safety and immunogenicity of early infant vaccination with 7-valent pneumococcal conjugate vaccine (7vPCV), we investigated the impact of early schedules on pneumococcal carriage. Infants were randomized at birth to receive 7vPCV in a 0–1–2-month (n = 101) or a 1–2–3-month (n = 105) schedule or no 7vPCV (n = 106). All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. We cultured nasopharyngeal swabs (NPS) collected at ages 1, 2, 3, 4 weeks and 3, 9, 18 months, and middle ear discharge if present. Pneumococcal serotypes were identified by the Quellung reaction. A total of 1761 NPS were cultured. The prevalence of pneumococcal carriage was 22% at 1 week of age, rising to 80% by age 3 months and remained >70% thereafter, with high-density carriage in 42% of pneumococcuspositive samples. We identified 63 different serotypes; 43% of isolates from controls were 13vPCV serotypes. There were no significant differences in 7vPCV serotype carriage between 7vPCV recipients and controls at any age (22% vs. 31% at 9 months, p = 0.2). At age 9 months the prevalence of non-7vPCV carriage was 17% higher in 7vPCV recipients (48%) than in controls (25%, p = 0.02). More non-7vPCV serotypes were isolated from ear discharge in 16 7vPCV recipients than from 4 controls (48% vs. 25%, p = 0.13). The limited impact of neonatal or accelerated infant 7vPCV schedules on vaccine serotype carriage is probably due to the early onset of dense carriage of a broad range of pneumococcal serotypes. While serotype-independent pneumococcal vaccines are needed in high-risk populations, the underlying environmental factors and sources of infection must be investigated.
- Authors: Aho, Celestine , Michael, Audrey , Yoannes, Mition , Greenhill, Andrew , Jacoby, Peter , Reeder, John , Pomat, William , Saleu, Gerard , Namuigi, Pioto , Phuanukoonnon, Suparat , Smith-Vaughan, Heidi , Leach, Amanda , Richmond, Peter , Lehmann, Deborah
- Date: 2016
- Type: Text , Journal article
- Relation: Vaccine Reports Vol. 6, no. (2016), p. 36-43
- Full Text:
- Reviewed:
- Description: Streptococcus pneumoniae is a leading cause of pneumonia, the most common cause of childhood death. Papua New Guinean children experience high rates of nasopharyngeal pneumococcal colonization within weeks of birth, predisposing them to pneumococcal disease. In a trial to determine the safety and immunogenicity of early infant vaccination with 7-valent pneumococcal conjugate vaccine (7vPCV), we investigated the impact of early schedules on pneumococcal carriage. Infants were randomized at birth to receive 7vPCV in a 0–1–2-month (n = 101) or a 1–2–3-month (n = 105) schedule or no 7vPCV (n = 106). All children received 23-valent pneumococcal polysaccharide vaccine at age 9 months. We cultured nasopharyngeal swabs (NPS) collected at ages 1, 2, 3, 4 weeks and 3, 9, 18 months, and middle ear discharge if present. Pneumococcal serotypes were identified by the Quellung reaction. A total of 1761 NPS were cultured. The prevalence of pneumococcal carriage was 22% at 1 week of age, rising to 80% by age 3 months and remained >70% thereafter, with high-density carriage in 42% of pneumococcuspositive samples. We identified 63 different serotypes; 43% of isolates from controls were 13vPCV serotypes. There were no significant differences in 7vPCV serotype carriage between 7vPCV recipients and controls at any age (22% vs. 31% at 9 months, p = 0.2). At age 9 months the prevalence of non-7vPCV carriage was 17% higher in 7vPCV recipients (48%) than in controls (25%, p = 0.02). More non-7vPCV serotypes were isolated from ear discharge in 16 7vPCV recipients than from 4 controls (48% vs. 25%, p = 0.13). The limited impact of neonatal or accelerated infant 7vPCV schedules on vaccine serotype carriage is probably due to the early onset of dense carriage of a broad range of pneumococcal serotypes. While serotype-independent pneumococcal vaccines are needed in high-risk populations, the underlying environmental factors and sources of infection must be investigated.
Understanding barriers to mental health service utilization for adolescents in rural Australia
- Aisbett, Damon, Boyd, Candice, Francis, Kristy, Newnham, Krystal, Newnham, Karyn
- Authors: Aisbett, Damon , Boyd, Candice , Francis, Kristy , Newnham, Krystal , Newnham, Karyn
- Date: 2007
- Type: Text , Journal article
- Relation: Rural and Remote Health Vol. 7, no. (2007), p. 1-10
- Full Text:
- Reviewed:
- Description: INTRODUCTION: There is a general paucity of research in the area of rural adolescent mental health in Australia, and in particular a lack of data regarding the experiences of rural adolescents who seek help for mental health problems. This study used a qualitative approach to data collection and analysis in order to assist understanding of the barriers to mental health service utilization for young people in rural communities. METHOD: A series of interviews were conducted with each of the study's participants, who ranged in age from 15 to 17 years. All participants were clients of the Child and Adolescent Mental Health Services in the rural cities of Horsham and Ararat, Victoria, Australia. RESULTS: Participants described how the lack of reliable transport to and from the mental health service affected the utilization of the service by rural young people. They also expressed concern regarding a lack of qualified professionals in their region who specialize in child and adolescent mental health. Participants reported frustration at long waiting lists and the lack of an after-hours service. One participant shared her experiences of deliberate self-harm to in order to gain access. Results also revealed that rural gossip networks and social visibility within rural communities compounded the experience of stigma and social exclusion for these young people. Furthermore, participants explained how these experiences negatively impacted on their utilization of the mental health service and their progress towards recovery. CONCLUSIONS: There are several barriers to mental health service utilization for rural adolescents which affect both their decision to access help as well as their ability to engage effectively with mental health services over time. Clinicians who work with rural adolescents need to be mindful of the influence of rural culture on mental health service utilization by young people. The co-location of mental health services and general health services is suggested as one way to reduce the fear associated with 'being seen' entering a stand-alone mental health service. It is suggested that treatment programs for adolescents in rural areas address the different types of stigma that these young people are likely to encounter. Furthermore, community and school-based interventions aimed at reducing the social stigma of young people with mental illness in rural areas is recommended.
- Description: C1
- Description: 2003005804
- Authors: Aisbett, Damon , Boyd, Candice , Francis, Kristy , Newnham, Krystal , Newnham, Karyn
- Date: 2007
- Type: Text , Journal article
- Relation: Rural and Remote Health Vol. 7, no. (2007), p. 1-10
- Full Text:
- Reviewed:
- Description: INTRODUCTION: There is a general paucity of research in the area of rural adolescent mental health in Australia, and in particular a lack of data regarding the experiences of rural adolescents who seek help for mental health problems. This study used a qualitative approach to data collection and analysis in order to assist understanding of the barriers to mental health service utilization for young people in rural communities. METHOD: A series of interviews were conducted with each of the study's participants, who ranged in age from 15 to 17 years. All participants were clients of the Child and Adolescent Mental Health Services in the rural cities of Horsham and Ararat, Victoria, Australia. RESULTS: Participants described how the lack of reliable transport to and from the mental health service affected the utilization of the service by rural young people. They also expressed concern regarding a lack of qualified professionals in their region who specialize in child and adolescent mental health. Participants reported frustration at long waiting lists and the lack of an after-hours service. One participant shared her experiences of deliberate self-harm to in order to gain access. Results also revealed that rural gossip networks and social visibility within rural communities compounded the experience of stigma and social exclusion for these young people. Furthermore, participants explained how these experiences negatively impacted on their utilization of the mental health service and their progress towards recovery. CONCLUSIONS: There are several barriers to mental health service utilization for rural adolescents which affect both their decision to access help as well as their ability to engage effectively with mental health services over time. Clinicians who work with rural adolescents need to be mindful of the influence of rural culture on mental health service utilization by young people. The co-location of mental health services and general health services is suggested as one way to reduce the fear associated with 'being seen' entering a stand-alone mental health service. It is suggested that treatment programs for adolescents in rural areas address the different types of stigma that these young people are likely to encounter. Furthermore, community and school-based interventions aimed at reducing the social stigma of young people with mental illness in rural areas is recommended.
- Description: C1
- Description: 2003005804
Interpretive phenomenological approaches to rural mental health research
- Authors: Aisbett, Damon
- Date: 2006
- Type: Text , Journal article
- Relation: Rural Social Work and Community Practice Vol. 11, no. (2006), p. 52-58
- Full Text:
- Reviewed:
- Description: While researchers in the fields of social work and nursing have recognised the usefulness of qualitative research methods for many years, researchers in psychology have tended to lag behind in their understanding of the value and applicability of qualitative approaches. The aims of this article are to consider the role of qualitative research in psychology, to outline the various steps involved in conducting qualitative data collection and Interpretive Phenomenological Analysis (IPA) for those not versed in these techniques, and to provide a case example of the applicability of these methods to rural adolescent mental health research. The final section of this article includes a detailed discussion of the advantages and limitations of IPA.
- Description: C1
- Description: 2003001977
Sink mobility aware energy-efficient network integrated super heterogeneous protocol for WSNs
- Akbar, Mariam, Javaid, Nadeem, Imran, Muhammad, Amjad, Naeem, Khan, Majid, Guizani, Mohsen
- Authors: Akbar, Mariam , Javaid, Nadeem , Imran, Muhammad , Amjad, Naeem , Khan, Majid , Guizani, Mohsen
- Date: 2016
- Type: Text , Journal article
- Relation: Eurasip Journal on Wireless Communications and Networking Vol. 2016, no. 1 (2016), p. 1-19
- Full Text:
- Reviewed:
- Description: In this paper, we propose Balanced Energy-Efficient Network Integrated Super Heterogeneous (BEENISH), improved BEENISH (iBEENISH), Mobile BEENISH (MBEENISH), and improved Mobile BEENISH (iMBEENISH) protocols for heterogeneous wireless sensor networks (WSNs). BEENISH considers four energy levels of nodes and selects cluster heads (CHs) on the base of residual energy levels of nodes and average energy level of the network, whereas iBEENISH dynamically varies the CHs selection probability in an efficient manner leading to increased network lifetime. We also present a mathematical sink mobility model and validate this model by implementing it in BEENISH (resulting in MBEENISH) and iBEENISH (resulting in iMBEENISH). Finally, simulation results show that BEENISH, MBEENISH, iBEENISH, and iMBEENISH protocols outperform contemporary protocols in terms of stability period, network lifetime, and throughput. © 2016, Akbar et al.
- Authors: Akbar, Mariam , Javaid, Nadeem , Imran, Muhammad , Amjad, Naeem , Khan, Majid , Guizani, Mohsen
- Date: 2016
- Type: Text , Journal article
- Relation: Eurasip Journal on Wireless Communications and Networking Vol. 2016, no. 1 (2016), p. 1-19
- Full Text:
- Reviewed:
- Description: In this paper, we propose Balanced Energy-Efficient Network Integrated Super Heterogeneous (BEENISH), improved BEENISH (iBEENISH), Mobile BEENISH (MBEENISH), and improved Mobile BEENISH (iMBEENISH) protocols for heterogeneous wireless sensor networks (WSNs). BEENISH considers four energy levels of nodes and selects cluster heads (CHs) on the base of residual energy levels of nodes and average energy level of the network, whereas iBEENISH dynamically varies the CHs selection probability in an efficient manner leading to increased network lifetime. We also present a mathematical sink mobility model and validate this model by implementing it in BEENISH (resulting in MBEENISH) and iBEENISH (resulting in iMBEENISH). Finally, simulation results show that BEENISH, MBEENISH, iBEENISH, and iMBEENISH protocols outperform contemporary protocols in terms of stability period, network lifetime, and throughput. © 2016, Akbar et al.
A multi-hop angular routing protocol for wireless sensor networks
- Akbar, Mariam, Javaid, Nadeem, Imran, Muhammad, Rao, Areeba, Younis, Muhammad, Niaz, Iftikhar
- Authors: Akbar, Mariam , Javaid, Nadeem , Imran, Muhammad , Rao, Areeba , Younis, Muhammad , Niaz, Iftikhar
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Distributed Sensor Networks Vol. 12, no. 9 (2016), p.
- Full Text:
- Reviewed:
- Description: In this article, we propose two new routing protocols for wireless sensor networks. First one is AM-DisCNT (angular multi-hop distance-based clustering network transmission) protocol which uses circular deployment of sensors (nodes) for uniform energy consumption in the network. The protocol operates in such a way that nodes with maximum residual energy are selected as cluster heads for each round. Second one is iAM-DisCNT (improved AM-DisCNT) protocol which exploits both mobile and static base stations for throughput maximization. Besides the proposition of routing protocols, iAM-DisCNT is provided with three mathematical models: two linear-programming-based models for information flow maximization and packet drop rate minimization and one model for calculating energy consumption of nodes. Graphical analysis for linear-programming-based mathematical formulation is also part of this work. Simulation results show that AM-DisCNT has 32% and iAM-DisCNT has 48% improved stability period as compared to LEACH (low-energy adaptive clustering hierarchy) and DEEC (distributed energy-efficient clustering) routing protocols. Similarly, throughput of AM-DisCNT and iAM-DisCNT is improved by 16% and 80%, respectively, in comparison with the counterpart schemes. © The Author(s) 2016.
- Authors: Akbar, Mariam , Javaid, Nadeem , Imran, Muhammad , Rao, Areeba , Younis, Muhammad , Niaz, Iftikhar
- Date: 2016
- Type: Text , Journal article
- Relation: International Journal of Distributed Sensor Networks Vol. 12, no. 9 (2016), p.
- Full Text:
- Reviewed:
- Description: In this article, we propose two new routing protocols for wireless sensor networks. First one is AM-DisCNT (angular multi-hop distance-based clustering network transmission) protocol which uses circular deployment of sensors (nodes) for uniform energy consumption in the network. The protocol operates in such a way that nodes with maximum residual energy are selected as cluster heads for each round. Second one is iAM-DisCNT (improved AM-DisCNT) protocol which exploits both mobile and static base stations for throughput maximization. Besides the proposition of routing protocols, iAM-DisCNT is provided with three mathematical models: two linear-programming-based models for information flow maximization and packet drop rate minimization and one model for calculating energy consumption of nodes. Graphical analysis for linear-programming-based mathematical formulation is also part of this work. Simulation results show that AM-DisCNT has 32% and iAM-DisCNT has 48% improved stability period as compared to LEACH (low-energy adaptive clustering hierarchy) and DEEC (distributed energy-efficient clustering) routing protocols. Similarly, throughput of AM-DisCNT and iAM-DisCNT is improved by 16% and 80%, respectively, in comparison with the counterpart schemes. © The Author(s) 2016.