The in vitro anthelmintic effects of plumbagin on newly excysted and 4-weeks-old juvenile parasites of Fasciola gigantica
- Authors: Lorsuwannarat, Natcha , Piedrafita, David , Chantree, Pathanin , Sansri, Veerawat , Songkoomkrong, Sineenart , Bantuchai, Sirasate , Sangpairot, Kant , Kueakhai, Pornanan , Changklungmoa, Narin , Chaichanasak, Pannigan , Chansela, Piyachat , Sobhon, Prasert
- Date: 2013
- Type: Text , Journal article
- Relation: Experimental Parasitology Vol. 136, no. 1 (2013), p. 5-13
- Full Text: false
- Reviewed:
- Description: The effect of plumbagin (PB, 5-hydroxy-2-methyl-1,4-naphthoquinone) against newly excysted juveniles (NEJs) and 4-weeks-old immature parasites of Fasciola gigantica were compared with triclabendazole (TCZ). The anthelmintic efficacy of 1, 10 and 100. μg/ml of PB or TCZ following incubation in vitro for 1-24. h was compared using a combination of relative motility (RM), survival index (SI) and larval migration inhibition (LMI) assays for parasite viability. The RM and SI values of the PB-treated group decreased at a more rapid rate than the TCZ-treated group. For NEJs, the decreased RM values were first observed at 1. h incubation with 1. μg/ml PB, and 90% of flukes were killed at 24. h. In contrast, in TCZ-treated groups a 10-fold higher concentration of TCZ (10. μg/ml) resulted in only 9% dead parasites after 24. h incubation. In 4-weeks-old juvenile parasites, PB reduced the RM value at 10. μg/ml with 100% of flukes dead after 3. h, while TCZ decreased RM values at the concentration of 100. μg/ml but with only 5% of flukes killed at 24. h. NEJs treated with PB exhibited 88%, 99% and 100% of LMIs at the concentrations of 1, 10 and 100. μg/ml, respectively. NEJs incubated with TCZ have an LMI of only 32% at the highest concentration of 100. μg/ml. Similarly PB had a significantly greater killing of immature 4. weeks juvenile stages than TCZ at all concentrations; however, 4-weeks-old juvenile parasites were more resistant to killing by PB or TCZ at all concentrations when compared to NEJs. Further studies were carried out to investigate the alterations of the parasite tegument by scanning electron microscope (SEM). PB caused similar tegumental alterations in 4-weeks-old juveniles as those observed in TCZ treatment but with greater damage at comparative time points, comprising of swelling, blebbing and rupture of the tegument, loss of spines, and eventual erosion, lesion and desquamation of the total tegument. These data indicate that PB had a greater fasciolicidal effect against immature stages of F. gigantica parasites than TCZ and warrant further studies for use as a potential new anthelmintic against Fasciola infections. © 2013 Elsevier Inc.
Attention-deficit/hyperactivity disorder symptoms in an adult sample : Associations with cloninger's temperament and character dimensions
- Authors: Gomez, Rapson , Woodworth, Rosalind , Waugh, Megan , Corr, Philip
- Date: 2012
- Type: Text , Journal article
- Relation: Personality and Individual Differences Vol. 52, no. 3 (2012), p. 290-294
- Full Text: false
- Reviewed:
- Description: Relationships between C.R. Cloninger's temperament and character dimensions and the Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms of inattention (IA) and hyperactivity/impulsivity (HI) were examined in 231 adults from the general population. Regression analyses that predicated overall ADHD, IA and HI by the seven temperament/character dimensions revealed: IA was predicted positively by Harm Avoidance and negatively by Self-Directedness; HI was predicted positively by Persistence; and overall ADHD was predicted negatively by Self-Directedness. These findings are also interpreted in terms of current theories of ADHD, and the related original and revised versions of Gray's reinforcement sensitivity theory (RST) of personality. © 2011.
Liver fluke vaccines in ruminants : Strategies, progress and future opportunities
- Authors: Toet, Hayley , Piedrafita, David , Spithill, Terry
- Date: 2014
- Type: Text , Journal article , Review
- Relation: International Journal for Parasitology Vol. 44, no. 12 (2014), p. 915-927
- Full Text: false
- Reviewed:
- Description: The development of a vaccine for Fasciola spp. in livestock is a challenge and would be advanced by harnessing our knowledge of acquired immune mechanisms expressed by resistant livestock against fluke infection. Antibody-dependent cell-mediated cytotoxicity directed to the surface tegument of juvenile/immature flukes is a host immune effector mechanism, suggesting that antigens on the surface of young flukes may represent prime candidates for a fluke vaccine. A Type 1 immune response shortly after fluke infection is associated with resistance to infection in resistant sheep, indicating that vaccine formulations should attempt to induce Type 1 responses to enhance vaccine efficacy. In cattle or sheep, an optimal fluke vaccine would need to reduce mean fluke burdens in a herd below the threshold of 30-54 flukes to ensure sustainable production benefits. Fluke infection intensity data suggest that vaccine efficacy of approximately 80% is required to reduce fluke burdens below this threshold in most countries. With the increased global prevalence of triclabendazole-resistant Fasciola hepatica, it may be commercially feasible in the short term to introduce a fluke vaccine of reasonable efficacy that will provide economic benefits for producers in regions where chemical control of new drug-resistant fluke infections is not viable. Commercial partnerships will be needed to fast-track new candidate vaccines using acceptable adjuvants in relevant production animals, obviating the need to evaluate vaccine antigens in rodent models. © 2014 Australian Society for Parasitology Inc.
SCAT3 changes from baseline and associations with X2 Patch measured head acceleration in amateur Australian football players
- Authors: Willmott, Catherine , McIntosh, Andrew , Howard, Teresa , Mitra, Biswadev , Dimech-Betancourt, Bleydy , Donovan, Jarrod , Rosenfeld, Jeffrey
- Date: 2018
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 21, no. 5 (2018), p. 442-446
- Full Text: false
- Reviewed:
- Description: Objectives: To investigate changes from baseline on SCAT3 as a result of football game exposure, and association with X2 Patch measured head acceleration events in amateur Australian footballers. Design: Prospective cohort. Methods: Peak linear acceleration (PLA) of the head (>10 g) was measured by wearable head acceleration sensor X2 Biosystems X-Patch in male (n = 34) and female (n = 19) Australian footballers. SCAT3 was administered at baseline (B) and post-game (PG). Results: 1394 head acceleration events (HEA) >10 g were measured. Mean and median HEA PLA were recorded as 15.2 g (SD = 9.2, range = 10.0–115.8) and 12.4 g (IQR = 11.0–15.6) respectively. No significant difference in median HEA PLA (g) was detected across gender (p = 0.55), however, more HEAs were recorded in males (p = 0.03). A greater number (p = 0.004) and severity (p < 0.001) of symptoms were reported PG than at B. No significant association between number of HEA or median PLA, and SCAT3 change scores (p > 0.05 for all), was identified for either gender. Conclusions: Increase in symptom severity post game was not associated with X2 measured HEA. Males sustained more HEA, however HEA PLA magnitude did not differ across gender. Further work on the validation of head acceleration sensors is required and their role in sports concussion research and medical management. © 2017 Sports Medicine Australia
Coronary artery disease predisposing haplogroup I of the Y chromosome, aggression and sex steroids - Genetic association analysis
- Authors: Bloomer, Lisa , Nelson, Christopher , Denniff, Matthew , Christofidou, Paraskevi , Debiec, Radoslaw , Thompson, John , Zukowska-Szczechowska, Ewa , Samani, Nilesh , Charchar, Fadi , Tomaszewski, Maciej
- Date: 2014
- Type: Text , Journal article
- Relation: Atherosclerosis Vol. 233, no. 1 (2014), p. 160-164
- Relation: http://purl.org/au-research/grants/nhmrc/1009490
- Full Text: false
- Reviewed:
- Description: Objective: Amongst middle-aged men, haplogroup I is associated with approximate to 50% higher risk of coronary artery disease than other paternal lineages of Y chromosome. We hypothesised that carriers of haplogroup I had higher levels of aggression and estrogens and/or lower levels of androgens early in life and thus might be more prone to cardiovascular disease than men with other lineages of Y chromosome. Methods: We reconstructed phylogenetic tree of the Y chromosome in > 1000 young apparently healthy white men from the general population. Each Y chromosome was classified into one of 13 most common European lineages. Androgens (DHEA-S, androstenedione, total testosterone) and their metabolites (total estradiol, estrone) were measured by radioimmunoassays. Information on five dimensions of aggression (total, physical, verbal, anger and hostility) was collected using Buss and Perry questionnaire. Results: Approximately 17% men inherited haplogroup I from their fathers. Carriers of haplogroup I showed lower scores of verbal aggression than men with other haplogroups (beta = -0.72, SE = 0.29, P = 0.012) and when further compared to carriers of most common R1a lineage and other haplogroups (beta = -1.03, SE = 0.34, P = 0.003). However, these associations did not survive a correction for multiple testing. Sex steroids did not show even nominal level of association with haplogroup I. Conclusion: Our data show no overall association between haplogroup I and sex-related phenotypes in young white men. These results also suggest that the previously identified association between haplogroup I and coronary artery disease is not likely mediated by unfavourable profile of sex steroids or heightened aggression early in life. (C) 2014 Elsevier Ireland Ltd. All rights reserved.
Using the local immune response from the natural buffalo host to generate an antibody fragment library that binds the early larval stages of Schistosoma japonicum
- Authors: Hosking, Christopher , Driguez, Patrick , McWilliam, Hamish , Ilag, Leodevico , Gladman, Simon , Li, Yuesheng , Piedrafita, David , McManus, Donald , Meeusen, Els , De Veer, Michael
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal for Parasitology Vol. 45, no. 11 (2015), p. 729-740
- Full Text: false
- Reviewed:
- Description: Antibodies isolated from the local draining inguinal lymph node of field exposed-water buffaloes following challenge with Schistosoma japonicum cercariae showed high reactivity towards S. japonicum antigen preparations and bound specifically to formaldehyde-fixed S. japonicum schistosomules. Using this specific local immune response we produced a series of single-chain antibody Fv domain libraries from the same lymph nodes. Removal of phage that cross reacted with epitopes on adult parasites yielded a single-chain antibody Fv domain-phage library that specifically bound to whole formaldehyde-fixed and live S. japonicum schistosomules. DNA sequencing indicated clear enrichment of the single-chain antibody Fv domain library for buffalo B-cell complementarity determining regions post-selection for schistosomule binding. This study also revealed that long heavy chain complementarity determining regions appear to be an important factor when selecting for antibody binding fragments against schistosomule proteins. The selected single-chain antibody Fv domain-phage were used to probe a schistosome-specific protein microarray, which resulted in the recognition of many proteins expressed across all schistosome life-cycle stages. Following absorption to adult worms, the single-chain antibody Fv domain-phage library showed significantly reduced binding to most proteins, whilst two proteins (NCBI GenBank accession numbers AY915878 and AY815196) showed increased binding. We have thus developed a unique set of host derived single-chain antibody Fv domains comprising buffalo B-cell variable regions that specifically bind to early S. japonicum life-stages. © 2015 Australian Society for Parasitology Inc..
Family support liaison in the witnessed resuscitation : A phenomenology study
- Authors: Hassankhani, Hadi , Zamanzade, Vahid , Rahmani, Azad , Haririan, Hamidreza , Porter, Joanne
- Date: 2017
- Type: Text , Journal article
- Relation: International Journal of Nursing Studies Vol. 74, no. (2017), p. 95-100
- Full Text: false
- Reviewed:
- Description: Background: Family-witnessed resuscitation remains controversial among clinicians from implementation to practice and there are a number of countries, such as Iran, where that is considered a low priority. Objective: To explore the lived experience of resuscitation team members with the presence of the patient's family during resuscitation. Settings: The emergency departments and critical care units of 6 tertiary hospitals in Tabriz, Iran. Participants: There were potentially 380 nurses and physicians working in the emergency departments and acute care settings of 6 tertiary hospitals in Tabriz. A purposive sample of these nurses and physicians was used to recruit participants who had at least 2 years of experience, had experienced an actual family witnessed resuscitation event, and wanted to participate. The sample size was determined according to data saturation. Data collection ended when the data were considered rich and varied enough to illuminate the phenomenon, and no new themes emerged following the interview of 12 nurses and 8 physicians. Methods: Semi-structured, face-to-face interviews were held with the participants over a period of 6 months (April 2015 to September 2015), and Van Manen's method of data analysis was adopted. Results: Three main themes emerged from the data analysis, including 'Futile resuscitation', 'Family support liaison', and 'Influence on team's performance'. A further 9 sub-themes emerged under the 3 main themes, which included 'futile resuscitation in end-stage cancer patients', 'when a patient dies', 'young patients', 'care of the elderly', 'accountable person', 'family supporter', 'no influence', 'positive influence', and 'negative influence'. Conclusions: Participants noted both positive and negative experiences of having family members present during cardiopulmonary resuscitation. Welltrained and expert resuscitation team members are less likely to be stressed in the presence of family. A family support liaison would act to decrease family anxiety levels and to de-escalate any potentially aggressive person during the resuscitation. It is recommended that an experienced health care professional be designated to be responsible for explaining the process of resuscitation to the patient's family.
- Description: Bacicgrottral: Family-witnessed resuscitation remains controversial among clinicians from implementation to practice and there are a number of countries, such as Iran, where that is considered a low priority. Objective: To explore the lived experience of resuscitation team members with the presence of the patient's family during resuscitation. Settings: The emergency departments and critical care units of 6 tertiary hospitals in Tabriz, Iran. Participants: There were potentially 380 nurses and physicians working in the emergency departments and acute care settings of 6 tertiary hospitals in Tabriz. A purposive sample of these nurses and physicians was used to recruit participants who had at least 2 years of experience, had experienced an actual family witnessed resuscitation event, and wanted to participate. The sample size was determined according to data saturation. Data collection ended when the data were considered rich and varied enough to illuminate the phenomenon, and no new themes emerged following the interview of 12 nurses and 8 physicians. Methods: Semi-structured, face-to-face interviews were held with the participants over a period of 6 months (April 2015 to September 2015), and Van Manen's method of data analysis was adopted. Results: Three main themes emerged from the data analysis, including 'Futile resuscitation', 'Family support liaison', and 'Influence on team's performance'. A further 9 sub-themes emerged under the 3 main themes, which included 'futile resuscitation in end-stage cancer patients', 'when a patient dies', 'young patients', 'care of the elderly', 'accountable person', 'family supporter', 'no influence', 'positive influence', and 'negative influence'. Conclusions: Participants noted both positive and negative experiences of having family members present during cardiopulmonary resuscitation. Welltrained and expert resuscitation team members are less likely to be stressed in the presence of family. A family support liaison would act to decrease family anxiety levels and to de-escalate any potentially aggressive person during the resuscitation. It is recommended that an experienced health care professional be designated to be responsible for explaining the process of resuscitation to the patient's family.
A novel error indicator and an adaptive refinement technique using the scaled boundary finite element method
- Authors: Song, Chongmin , Ooi, Ean Tat , Pramod, Aladurthi , Natarajan, Sundararajan
- Date: 2018
- Type: Text , Journal article
- Relation: Engineering Analysis with Boundary Elements Vol. 94, no. (2018), p. 10-24
- Full Text: false
- Reviewed:
- Description: In this paper, an adaptive refinement strategy based on the scaled boundary finite element method on quadtree meshes for linear elasticity problems is discussed. Within this framework, the elements with hanging nodes are treated as polygonal elements and thus does not require special treatment. The adaptive refinement is supplemented with a novel error indicator. The local error is estimated directly from the solution of the scaled boundary governing equations. The salient feature is that it does not require any stress recovery techniques. The efficacy and the robustness of the proposed approach are demonstrated with a few numerical examples.
Spatial and temporal changes in estuarine water quality during a post-flood hypoxic event
- Authors: Wong, Vanessa , Johnston, Scott , Bush, Richard , Sullivan, Leigh , Clay, Christina , Burton, Edward , Slavich, Peter
- Date: 2010
- Type: Text , Journal article
- Relation: Estuarine, Coastal and Shelf Science Vol. 87, no. 1 (2010), p. 73-82
- Full Text: false
- Reviewed:
- Description: A major fish kill occurred in the Richmond River estuary in January 2008 due to oxygen depletion following extensive overbank flooding. This paper examines spatial and temporal changes in the chemistry of main channel waters, thereby identifying the primary sources of deoxygenating water. Over 40 km of the mid- to lower estuary main channel was deoxygenated within seven days of the flood peak. Hypoxia was confined to downstream of the confluences with mid-estuary backswamp basins and occurred during the later phase of the flood recession. Water chemistry at key locations in the estuary indicated elevated concentrations of redox sensitive species associated with acid sulfate soils (ASS) during the hypoxic period. Peak concentrations of Fe
A scaled boundary finite element formulation over arbitrary faceted star convex polyhedra
- Authors: Natarajan, Sundararajan , Ooi, Ean Tat , Saputra, Albert , Song, Chongmin
- Date: 2017
- Type: Text , Journal article
- Relation: Engineering Analysis with Boundary Elements Vol. 80, no. (2017), p. 218-229
- Full Text: false
- Reviewed:
- Description: In this paper, a displacement based finite element framework for general three-dimensional convex polyhedra is presented. The method is based on a semi-analytical framework, the scaled boundary finite element method. The method relies on the definition of a scaling center from which the entire boundary is visible. The salient feature of the method is that the discretizations are restricted to the surfaces of the polyhedron, thus reducing the dimensionality of the problem by one. Hence, an explicit form of the shape functions inside the polyhedron is not required. Conforming shape functions defined over arbitrary polygon, such as the Wachpress interpolants are used over each surface of the polyhedron. Analytical integration is employed within the polyhedron. The proposed method passes patch test to machine precision. The convergence and the accuracy properties of the method is discussed by solving few benchmark problems in linear elasticity. © 2017 Elsevier Ltd
Acoustic emission source location on large plate-like structures using a local triangular sensor array
- Authors: Aljets, Dirk , Chong, Alex , Wilcox, Steven , Holford, Karen
- Date: 2012
- Type: Text , Journal article
- Relation: Mechanical Systems and Signal Processing Vol. 30, no. (2012), p. 91-102
- Full Text: false
- Reviewed:
- Description: A new acoustic emission (AE) source location method was developed for large plate-like structures, which evaluates the location of the source using a combined time of flight and modal source location algorithm. Three sensors are installed in a triangular array with a sensor to sensor distance of just a few centimeters. The direction from the sensor array to the AE source can be established by analysing the arrival times of the A 0 component of the signal to the three sensors whilst the distance can be evaluated using the separation of S 0 and A 0 mode at each sensor respectively. The close positioning of the sensors allows the array to be installed in a single housing. This simplifies mounting, wiring and calibration procedures for non-destructive testing (NDT) and structural health monitoring (SHM) applications. Furthermore, this array could reduce the number of sensors needed to monitor large structures compared to other methods. An automatic wave mode identification method is also presented. © 2012 Elsevier Ltd.
Near miss experiences of transport and recreational cyclists in New South Wales, Australia. Findings from a prospective cohort study
- Authors: Poulos, Roslyn , Hatfield, Julie , Rissel, Chris , Flack, Lloyd , Shaw, Louise , Grzebieta, Raphael , McIntosh, Andrew
- Date: 2017
- Type: Text , Journal article
- Relation: Accident Analysis and Prevention Vol. 101, no. (2017), p. 143-153
- Full Text: false
- Reviewed:
- Description: This paper investigates events in which cyclists perceive a cycling crash is narrowly avoided (henceforth, a near miss). A cohort of 2038 adult transport and recreational cyclists from New South Wales (Australia) provided self-reported prospectively collected data from cycling diaries to allow the calculation of an exposure-based rate of near misses and investigation of near miss circumstances. During 25,971 days of cycling, 3437 near misses were reported. For a given time cycling, cyclists who rode mainly for transport (compared with those who rode mainly for recreation), and cyclists with less experience (compared to those with more experience) were more likely to report a near miss; older cyclists (60+ years) were less likely to report a near miss than younger cyclists (25-59 years). Where type of near miss was recorded, 72.0% involved motor vehicles, 10.9% involved pedestrians and 6.9% involved other cyclists. Results indicate some similarities between near misses and crashes reported by this cohort during the same reporting period. A bias toward reporting near misses with motor Vehicles was suggested, which likely reflects cyclists' perceptions that crashes involving motor vehicles are particularly serious, and highlights their impact on perceived safety. Given the relative rarity of crashes, and the limited breadth and depth of administrative data, collection of near miss data may contribute to our understanding of cycling safety by increasing the volume and detail of information available for analysis. Addressing the causes of near misses may offer an opportunity to improve both perceived and actual safety for cyclists. (C) 2017 Elsevier Ltd. All rights reserved.
Using Tinder® to start a fire : Predicting antisocial use of Tinder® with gender and the Dark Tetrad
- Authors: Duncan, Zoe , March, Evita
- Date: 2019
- Type: Text , Journal article
- Relation: Personality and Individual Differences Vol. 145, no. (2019), p. 9-14
- Full Text: false
- Reviewed:
- Description: Online dating continues to grow in popularity and is associated with significant advantages; however, experiencing antisocial behaviours when online dating is a distinct possibility. The aim of the current study was to explore the utility of gender and the dark personality traits of narcissism, Machiavellianism, psychopathy, and sadism in predicting perpetration of a range of antisocial behaviours on the popular dating app Tinder. It was hypothesised that the male gender and higher scores on these personality traits would predict perpetration of antisocial behaviours on Tinder. Participants (N = 587; 21% men, 79% women) completed an online questionnaire, including the Antisocial Uses of Tinder® Scale which was constructed to measure a range of antisocial behaviours. Exploratory and Confirmatory factor analyses revealed three forms of antisocial behaviours (General, esteem, and sexual) which explained over half of the variance (58.99%) of variance in the Antisocial Uses of Tinder® measure. Regression analyses were run for each form of antisocial behaviour, and the predictive utility of gender and the dark traits were found to differ across the antisocial behaviours. Results of the current study support an individual differences approach to exploring antisocial behaviours online, particularly when online dating.
Dynamic adjustment of sensing range for event coverage in wireless sensor networks
- Authors: Alam, Kh Mahmudul , Kamruzzaman, Joarder , Karmakar, Gour , Murhsed, Manzur
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of Network and Computer Applications Vol. 46, no. (2014), p. 139-153
- Full Text: false
- Reviewed:
- Description: One primary goal of sensor networks is to guarantee robust and accurate event detection while reducing energy consumption for extended lifetime. To increase detection fidelity, recent literature introduces redundancy in the sensor field either by maintaining fixed k-coverage throughout lifetime or by providing dynamic k-coverage using mobile sensors after an event is detected. The former requires a large number of sensor nodes and the latter is costly and sometimes infeasible as mobile node deployment in inaccessible areas is difficult. Exploiting recent advances that allow adjustable sensing and transmission radius for sensors, we propose a scheme that ensures 1-coverage at deployment time, but on detection, extends to k-coverage to increase accuracy and robustness. Using an adjustable sensing model through power adjustment, we formulate an optimization problem that determines the optimal sensor set whose sensing and transmission radius are to be adjusted to provide expected coverage degree, through minimizing a cost function comprising energy consumption and achievable accuracy in detection. For a given sensing adjustability, a guideline for deterministic and random deployment is presented to ensure initial coverage. Detection performance and network lifetime are analyzed both theoretically and through simulation. Our approach avoids over-provisioning in sensor network, increases lifetime and scalability, and maintains detection performance in a cost effective way.
Effect of spatial distribution of wax and PEG-isocyanate on the morphology and hydrophobicity of starch films
- Authors: Muscat, Delina , Adhikari, Raju , Tobin, Mark , McKnight, Stafford , Wakeling, Lara , Adhikari, Benu
- Date: 2014
- Type: Text , Journal article
- Relation: Carbohydrate Polymers Vol. 111, no. (2014), p. 333-347
- Full Text:
- Reviewed:
- Description: This study proposes a novel method for improving surface hydrophobicity of glycerol plasticized high amylose (HAG) films. We used polyethylene glycol isocyanate (PEG-iso) crosslinker to link HAG and three natural waxes (beeswax, candelilla wax and carnauba wax) to produce HAG + wax + PEG-iso films. The spatial distributions of wax and PEG-iso across the thickness of these films were determined using Synchrotron-based Fourier transform infrared spectroscopy. The hydrophobicity and surface morphology of the films were determined using contact angle (CA) and scanning electron microscopic measurements, respectively. The distribution patterns of wax and the PEG-iso across the thickness of the film, and the nature of crystalline patterns formed on the surface of these films were found to be the key factors affecting surface hydrophobicity. The highest hydrophobicity (CA >90°) was created when the PEG-iso was primarily distributed in the interior of the films and a hierarchical circular pinnacle structure of solidified wax was formed on the surface. © 2014 Elsevier Ltd.
Vibrations of a mass-spring system using a granular-material damper
- Authors: Zalewski, Robert , Chodkiewicz, Pawel , Shillor, Meir
- Date: 2016
- Type: Text , Journal article
- Relation: Applied Mathematical Modelling Vol. 40, no. 17-18 (2016), p. 8033-8047
- Full Text: false
- Reviewed:
- Description: The control of vibrations of a mass-spring system with a damper made of granular material is modeled, numerically simulated and experimentally verified. The damper consists of a hermetically closed flexible sleeve filled with granular material. Pumping air out of or into the sleeve increases or decreases the under-pressure, which increases or decreases the compression of the granules, causing the system to become more or less rigid. This, in turn, increases or decreases the energy dissipation, which provides the damping control mechanism of the system's vibrations. The spring is assumed to be nonlinear and once the coils are fully compressed it becomes essentially rigid. The changes to the damping characteristics of the damper caused by the rearrangement and compacting of the granules are described by a 'damage-like' variable- the granules rearrangement function. The model consists of a nonlinear ordinary differential equation for the mass-spring-damper system and a differential inclusion for the granules rearrangement function. A numerical algorithm for the problem is presented and simulations of the system behavior depicted. In particular, the changes in the oscillations of the system as the grain rearrangement progresses are shown. Then, the predictions of a version of the model are compared to experimental results that are presented briefly. The numerical results are fully supported by the experiments. It is concluded that a granular material damper may be an easy to implement and cost effective way to dampen vibrations of a mechanical system. (C) 2016 Elsevier Inc. All rights reserved.
Density-ratio based clustering for discovering clusters with varying densities
- Authors: Zhu, Ye , Ting, Kaiming , Carman, Mark
- Date: 2016
- Type: Text , Journal article
- Relation: Pattern Recognition Vol. 60, no. (2016), p. 983-997
- Full Text: false
- Reviewed:
- Description: Density-based clustering algorithms are able to identify clusters of arbitrary shapes and sizes in a dataset which contains noise. It is well-known that most of these algorithms, which use a global density threshold, have difficulty identifying all clusters in a dataset having clusters of greatly varying densities. This paper identifies and analyses the condition under which density-based clustering algorithms fail in this scenario. It proposes a density-ratio based method to overcome this weakness, and reveals that it can be implemented in two approaches. One approach is to modify a density-based clustering algorithm to do density-ratio based clustering by using its density estimator to compute density-ratio. The other approach involves rescaling the given dataset only. An existing density-based clustering algorithm, which is applied to the rescaled dataset, can find all clusters with varying densities that would otherwise impossible had the same algorithm been applied to the unscaled dataset. We provide an empirical evaluation using DBSCAN, OPTICS and SNN to show the effectiveness of these two approaches. © 2016 Elsevier Ltd
Modular implementation of artificial neural network in predicting in-flight particle characteristics of an atmospheric plasma spray process
- Authors: Choudhury, Tanveer , Berndt, Christopher , Man, Zhihong
- Date: 2015
- Type: Text , Journal article
- Relation: Engineering Applications of Artificial Intelligence Vol. 45, no. (2015), p. 57-70
- Full Text: false
- Reviewed:
- Description: This paper presents a modular implementation of an artificial neural network to model the atmospheric plasma spray process in predicting the in-flight particle characteristics from the input processing parameters. The in-flight particle characteristics influence the structure and properties of the thermal spray coating and, thus, are considered important parameters to comprehend, simulate and predict the manufacturing process. The modular implementation allows simplification of the optimized model structure with enhanced ability to generalise the network. As well, the underlying relationship between each of the output in-flight characteristics with respect to the input processing parameters is explored. Smaller networks are constructed that achieves better, or in some cases, similar results. The training process is found to be more robust and stable along with fewer fluctuations in the values of the network parameters. The networks also respond to the variations of the number of hidden layer neurons with some definite trend. The predictable trend enhances reliability of the application of the artificial neural network in modelling the atmospheric plasma spray process and overcomes the variability and non-linearity associated with the process. © 2015 Elsevier Ltd. All rights reserved.
A new scale for disaster nursing core competencies : Development and psychometric testing
- Authors: Al Thobaity, Abdulellah , Williams, Brett , Plummer, Virginia
- Date: 2016
- Type: Text , Journal article
- Relation: Australasian Emergency Nursing Journal Vol. 19, no. 1 (2016), p. 11-19
- Full Text: false
- Reviewed:
- Description: Background: All nurses must have core competencies in preparing for, responding to and recovering from a disaster. In the Kingdom of Saudi Arabia (KSA), as in many other countries, disaster nursing core competencies are not fully understood and lack reliable, validated tools. Thus, it is imperative to develop a scale for exploring disaster nursing core competencies, roles and barriers in the KSA. Objectives: This study's objective is to develop a valid, reliable scale that identifies and explores core competencies of disaster nursing, nurses' roles in disaster management and barriers to developing disaster nursing in the KSA. Methods: This study developed a new scale testing its validity and reliability. A principal component analysis (PCA) was used to develop and test psychometric properties of the new scale. The PCA used a purposive sample of nurses from emergency departments in two hospitals in the KSA. Participants rated 93 paper-based, self-report questionnaire items from 1 to 10 on a Likert scale. PCA using Varimax rotation was conducted to explore factors emerging from responses. Findings: The study's participants were 132 nurses (66% response rate). PCA of the 93 questionnaire items revealed 49 redundant items (which were deleted) and 3 factors with eigenvalues of >1. The remaining 44 items accounted for 77.3% of the total variance. The overall Cronbach's alpha was 0.96 for all factors: 0.98 for Factor 1, 0.92 for Factor 2 and 0.86 for Factor 3. Conclusions: This study provided a validated, reliable scale for exploring nurses' core competencies, nurses' roles and barriers to developing disaster nursing in the KSA. The new scale has many implications, such as for improving education, planning and curricula. © 2015.
In-vitro digestion of probiotic bacteria and omega-3 oil co-microencapsulated in whey protein isolate-gum Arabic complex coacervates
- Authors: Eratte, Divya , Dowling, Kim , Barrow, Colin , Adhikari, Benu
- Date: 2017
- Type: Text , Journal article
- Relation: Food Chemistry Vol. 227, no. (2017), p. 129-136
- Full Text: false
- Reviewed:
- Description: Solid co-microcapsules of omega-3 rich tuna oil and probiotic bacteria L. casei were produced using whey protein isolate-gum Arabic complex coacervate as wall material. The in-vitro digestibility of the co-microcapsules and microcapsules was studied in terms of survival of L. casei and release of oil in sequential exposure to simulated salivary, gastric and intestinal fluids. Co-microencapsulation significantly increased the survival and surface hydrophobicity and the ability of L. casei to adhere to the intestinal wall. No significant difference in the assimilative reduction of cholesterol was observed between the microencapsulated and co-microencapsulated L. casei. The pattern of release of oil from the microcapsules and co-microcapsules was similar. However, the content of total chemically intact omega-3 fatty acids was higher in the oil released from co-microcapsules than the oil released from microcapsules. The co-microencapsulation can deliver bacterial cells and omega-3 oil to human intestinal system with less impact on functional properties. © 2017 Elsevier Ltd