Near-infrared effectiveness on degraded core in tropical climates
- Authors: Jansen, Nicholas , Cooke, David , Harris, Anthony , McKnight, Stafford
- Date: 2017
- Type: Text , Journal article
- Relation: Economic Geology Vol. 112, no. 4 (2017), p. 1011-1019
- Full Text: false
- Reviewed:
- Description: In tropical climates, postdrilling oxidation of sulfide-rich core can severely degrade drill core, producing lowtemperature iron oxyhydroxides, sulfates, and clays. Variable growth of these secondary minerals in exposed drill core, combined with the hydration and degradation of primary hydrothermal minerals, may lead to the production of spurious results in near-infrared (NIR) spectroscopic studies. However, the NIR technique can remain an effective tool in assessing hydrothermal alteration, even in extremely degraded core. We have assessed the usefulness of the NIR technique on degraded core at the Ladolam gold deposit, Papua New Guinea. Here, we seek to determine whether the primary alteration mineralogy had been significantly transformed by postdrilling oxidation over several years of weathering. In doing so, the study tested whether NIR analysis can be an effective tool in the discrimination of primary hydrothermal minerals in degraded core. Our study was made possible using semiquantitative X-ray diffraction (QXRD) analyses of a drill hole in 2004, where samples were collected at 50-m intervals. We subsequently repeated NIR and QXRD analyses on the same drill core in 2012. After nine years of storage, the drill core had degraded considerably, with the growth of jarosite and other sulfates. Despite this, XRD results from 2004 and 2012 show no major differences in the primary alteration mineralogy. Closely spaced NIR analyses were conducted at 1-m intervals to increase the chance of obtaining a spectrum of the primary mineralogy and to exclude secondary oxidation minerals. The drill core, where possible, was broken immediately prior to analysis to obtain a fresh surface. On average, over a 10-m interval, approximately 25% of the NIR spectra did not contain secondary minerals and relict primary alteration minerals could be detected. The remaining spectra were affected by the occurrence of secondary jarosite, gypsum, and/or residual water, but in most cases, the primary alteration mineralogy could be determined. We conclude that NIR analyses remain an effective tool in the construction of geological deposit models when logging degraded historic core, even for sulfide-rich core that has degraded in tropical environments. © 2017 Society of Economic Geologists, Inc.
Antidepressant side effects and their impact on treatment outcome in people with major depressive disorder : an iSPOT-D report
- Authors: Braund, Taylor , Tillman, Gabriel , Palmer, Donna , Gordon, Evian , Rush, A. , Harris, Anthony
- Date: 2021
- Type: Text , Journal article
- Relation: Translational Psychiatry Vol. 11, no. 1 (2021), p.
- Full Text:
- Reviewed:
- Description: Side effects to antidepressant medications are common and can impact the prognosis of successful treatment outcome in people with major depressive disorder (MDD). However, few studies have investigated the severity of side effects over the course of treatment and their association with treatment outcome. Here we assessed the severity of side effects and the impact of treatment type and anxiety symptoms over the course of treatment, as well as whether side effects were associated with treatment outcome. Participants were N = 1008 adults with a current diagnosis of single-episode or recurrent, nonpsychotic MDD. Participants were randomised to receive escitalopram, sertraline, or venlafaxine-extended release with equal probability and reassessed at 8 weeks regarding Hamilton Rating Scale Depression (HRSD17) and Quick Inventory of Depressive Symptomatology (QIDS-SR16) remission and response. Severity of side effects were assessed using the Frequency, Intensity, and Burden of Side Effects Rating (FIBSER) scale and assessed at day 4 and weeks 2, 4, 6, and 8. Frequency, intensity, and burden of side effects were greatest at week 2, then only frequency and intensity of side effects gradually decreased up to week 6. Treatment type and anxiety symptoms did not impact the severity of side effects. A greater burden—but not frequency or intensity—of side effects was associated with poorer treatment outcome and as early as 4 days post-treatment. Together, this work provides an informative mapping of the progression of side effects throughout the treatment course and their association with treatment outcome. Importantly, the burden of side effects that are present as early as 4 days post-treatment predicts poorer treatment outcome and should be monitored closely. iSPOT-D: Registry name: ClinicalTrials.gov. Registration number: NCT00693849. © 2021, The Author(s).
Intrinsic functional connectomes characterize neuroticism in major depressive disorder and predict antidepressant treatment outcomes
- Authors: Braund, Taylor , Breukelaar, Isabella , Griffiths, Kristi , Tillman, Gabriel , Palmer, Donna , Bryant, Richard , Phillips, Mary , Harris, Anthony , Korgaonkar, Mayuresh
- Date: 2022
- Type: Text , Journal article
- Relation: Biological Psychiatry: Cognitive Neuroscience and Neuroimaging Vol. 7, no. 3 (2022), p. 276-284
- Full Text: false
- Reviewed:
- Description: Background: Antidepressant efficacy in people with major depressive disorder remains modest, yet identifying treatment-predictive neurobiological markers may improve outcomes. While disruptions in functional connectivity within and between large-scale brain networks predict poorer treatment outcome, it is unclear whether higher trait neuroticism, which has been associated with generally poorer outcomes, contributes to these disruptions and to antidepressant-specific treatment outcomes. Here, we used whole-brain functional connectivity analysis to identify a neural connectomic signature of neuroticism and tested whether this signature predicted antidepressant treatment outcome. Methods: Participants were 226 adults with major depressive disorder and 68 healthy control subjects who underwent functional magnetic resonance imaging and were assessed on clinical features at baseline. Participants with major depressive disorder were then randomized to 1 of 3 commonly prescribed antidepressants and after 8 weeks completed a second functional magnetic resonance imaging and were reassessed for depressive symptom remission/response. Baseline intrinsic functional connectivity between each pair of 436 brain regions was analyzed using network-based statistics to identify connectomic features associated with neuroticism. Features were then assessed on their ability to predict treatment outcome and whether they changed after 8 weeks of treatment. Results: Higher baseline neuroticism was associated with greater connectivity within and between the salience, executive control, and somatomotor brain networks. Greater connectivity across these networks predicted poorer treatment outcome that was not mediated by baseline neuroticism, and connectivity strength decreased after antidepressant treatment. Conclusions: Our findings demonstrate that neuroticism is associated with organization of intrinsic neural networks that predict treatment outcome, elucidating its biological underpinnings and opportunity for better treatment personalization. © 2021 Society of Biological Psychiatry