1,380 research outputs found
Depth perception not found in human observers for static or dynamic anti-correlated random dot stereograms
One of the greatest challenges in visual neuroscience is that of linking neural activity with perceptual experience. In the case of binocular depth perception, important insights have been achieved through comparing neural responses and the perception of depth, for carefully selected stimuli. One of the most important types of stimulus that has been used here is the anti-correlated random dot stereogram (ACRDS). In these stimuli, the contrast polarity of one half of a stereoscopic image is reversed. While neurons in cortical area V1 respond reliably to the binocular disparities in ACRDS, they do not create a sensation of depth. This discrepancy has been used to argue that depth perception must rely on neural activity elsewhere in the brain. Currently, the psychophysical results on which this argument rests are not clear-cut. While it is generally assumed that ACRDS do not support the perception of depth, some studies have reported that some people, some of the time, perceive depth in some types of these stimuli. Given the importance of these results for understanding the neural correlates of stereopsis, we studied depth perception in ACRDS using a large number of observers, in order to provide an unambiguous conclusion about the extent to which these stimuli support the perception of depth. We presented observers with random dot stereograms in which correlated dots were presented in a surrounding annulus and correlated or anti-correlated dots were presented in a central circular region. While observers could reliably report the depth of the central region for correlated stimuli, we found no evidence for depth perception in static or dynamic anti-correlated stimuli. Confidence ratings for stereoscopic perception were uniformly low for anti-correlated stimuli, but showed normal variation with disparity for correlated stimuli. These results establish that the inability of observers to perceive depth in ACRDS is a robust phenomenon
Extraction-free, direct determination of caffeine in microliter volumes of beverages by thermal desorption-gas chromatography mass spectrometry
An extraction-free method requiring microliter (μL) volumes has been developed for the determination of caffeine in beverages.Using a pyrolysis-gas chromatography mass spectrometry system, the conditions required for the direct thermal desorption-gaschromatography mass spectrometry (TD-GC/MS) determination of caffeine were optimised. A 5 μL aliquot was introduced to thethermal desorption unit, dried, and thermally desorbed to the GC/MS. *e response was linear over the range 10 to 500 μg/mL(R2 = 0.996). *e theoretical limit of detection (3 σ) was 0.456 μg/mL. No interferences were recorded from endogenous beveragecomponents or from commonly occurring drugs, such as nicotine, ibuprofen, and paracetamol. Replicate caffeine determinationson fortified latte style white coffee and Pepsi Max® gave mean recoveries of 93.4% (%CV = 4.1%) and 95.0% (%CV = 0.98%),respectively. Good agreement was also obtained with the stated values of caffeine for an energy drink and for Coca-Cola®. *esedata suggest that the method holds promise for the determination of caffeine in such samples
Changes in lipid composition during sexual development of the malaria parasite Plasmodium falciparum
Abstract
Background
The development of differentiated sexual stages (gametocytes) within human red blood cells is essential for the propagation of the malaria parasite, since only mature gametocytes will survive in the mosquito’s midgut. Hence gametocytogenesis is a pre-requisite for transmission of the disease. Physiological changes involved in sexual differentiation are still enigmatic. In particular the lipid metabolism—despite being central to cellular regulation and development—is not well explored.
Methods
Here the lipid profiles of red blood cells infected with the five different sexual stages of Plasmodium falciparum were analysed by mass spectrometry and compared to those from uninfected and asexual trophozoite infected erythrocytes.
Results
Fundamental differences between erythrocytes infected with the different parasite stages were revealed. In mature gametocytes many lipids that decrease in the trophozoite and early gametocyte infected red blood cells are regained. In particular, regulators of membrane fluidity, cholesterol and sphingomyelin, increased significantly during gametocyte maturation. Neutral lipids (serving mainly as caloriometric reserves) increased from 3 % of total lipids in uninfected to 27 % in stage V gametocyte infected red blood cells. The major membrane lipid class (phospholipids) decreased during gametocyte development.
Conclusions
The lipid profiles of infected erythrocytes are characteristic for the particular parasite life cycle and maturity stages of gametocytes. The obtained lipid profiles are crucial in revealing the lipid metabolism of malaria parasites and identifying targets to interfere with this deadly disease.We are grateful to the Australian Red Cross for providing human RBCs and
serum. Support of the Australian Research Council is acknowledged. TWM
is an Australian Research Council Future Fellow (FT110100249)
Recommended from our members
BIBFRAME beginnings at UT Austin
Slides from a panel discussion presented at the 2016 Texas Conference on Digital Libraries Special Forum: Exploring Linked Data for Libraries, which took place May 24, 2016.Staff from UT Libraries, the Harry Ransom Center, and the Tarlton Law Library have been collaborating in discussion group activities during the last year to develop knowledge and skills in anticipation of life after MARC, investigating the brave new world of linked data in libraries with a focus on the Library of Congress Bibliographic Framework (BIBFRAME) initiative.
Our group efforts to better understand BIBFRAME and linked data for libraries include in-depth discussions of current literature, webcasts, and presentations; strategic application of Zepheira’s Practical Practitioner training; and hands-on experimentation transforming local metadata in various formats for various resource types to BIBFRAME. Our analysis of the resulting transformations has helped us gain insight on mapping complexities, data loss, false transformations, potential new metadata displays, and the limitations of the tools involved. The experimentation process overall has afforded us the opportunity to ask targeted questions about what is needed to move towards linked data and to gain a better view of the frontier of Technical Services staff skillsets.
In this panel presentation, we’ll share details about our approaches to maximizing the group learning experience, and lessons learned from grappling with new concepts, data models, terminology, and tools. Representatives from our experimentation teams will report on the initial experience of transforming MARC and non-MARC data sets to BIBFRAME, and what we see as emerging questions and next steps.UT Librarie
Editorial : Curriculum Applications in Microbiology: Bioinformatics in the Classroom
We would like to thank all of the authors who submitted to this special topic, committed to the furthering of academic creativity, excellence, and rigor in the challenging and virtual instructional world of SARS-CoV-2 (COVID-19). To you and all of our educators globally, you are indispensable.Non peer reviewedPublisher PD
Identification and Characterization of σS, a Novel Component of the Staphylococcus aureus Stress and Virulence Responses
S. aureus is a highly successful pathogen that is speculated to be the most common cause of human disease. The progression of disease in S. aureus is subject to multi-factorial regulation, in response to the environments encountered during growth. This adaptive nature is thought to be central to pathogenesis, and is the result of multiple regulatory mechanisms employed in gene regulation. In this work we describe the existence of a novel S. aureus regulator, an as yet uncharacterized ECF-sigma factor (σS), that appears to be an important component of the stress and pathogenic responses of this organism. Using biochemical approaches we have shown that σS is able to associates with core-RNAP, and initiate transcription from its own coding region. Using a mutant strain we determined that σS is important for S. aureus survival during starvation, extended exposure to elevated growth temperatures, and Triton X-100 induced lysis. Coculture studies reveal that a σS mutant is significantly outcompeted by its parental strain, which is only exacerbated during prolonged growth (7 days), or in the presence of stressor compounds. Interestingly, transcriptional analysis determined that under standard conditions, S. aureus SH1000 does not initiate expression of sigS. Assays performed hourly for 72h revealed expression in typically background ranges. Analysis of a potential anti-sigma factor, encoded downstream of sigS, revealed it to have no obvious role in the upregulation of sigS expression. Using a murine model of septic arthritis, sigS-mutant infected animals lost significantly less weight, developed septic arthritis at significantly lower levels, and had increased survival rates. Studies of mounted immune responses reveal that sigS-mutant infected animals had significantly lower levels of IL-6, indicating only a weak immunological response. Finally, strains of S. aureus lacking sigS were far less able to undergo systemic dissemination, as determined by bacterial loads in the kidneys of infected animals. These results establish that σS is an important component in S. aureus fitness, and in its adaptation to stress. Additionally it appears to have a significant role in its pathogenic nature, and likely represents a key component in the S. aureus regulatory network
Sometimes you have to take the person and show them how : adapting behavioral activation for peer recovery specialist-delivery to improve methadone treatment retention
BACKGROUND: Despite efficacy of medication for opioid use disorder, low-income, ethno-racial minoritized populations often experience poor opioid use disorder treatment outcomes. Peer recovery specialists, individuals with lived experience of substance use and recovery, are well-positioned to engage hard-to-reach patients in treatment for opioid use disorder. Traditionally, peer recovery specialists have focused on bridging to care rather than delivering interventions. This study builds on research in other low-resource contexts that has explored peer delivery of evidence-based interventions, such as behavioral activation, to expand access to care.
METHODS: We sought feedback on the feasibility and acceptability of a peer recovery specialist-delivered behavioral activation intervention supporting retention in methadone treatment by increasing positive reinforcement. We recruited patients and staff at a community-based methadone treatment center and peer recovery specialist working across Baltimore City, Maryland, USA. Semi-structured interviews and focus groups inquired about the feasibility and acceptability of behavioral activation, recommendations for adaptation, and acceptability of working with a peer alongside methadone treatment.
RESULTS: Participants (N = 32) shared that peer recovery specialist-delivered behavioral activation could be feasible and acceptable with adaptations. They described common challenges associated with unstructured time, for which behavioral activation could be particularly relevant. Participants provided examples of how a peer-delivered intervention could fit well in the context of methadone treatment, emphasizing the importance of flexibility and specific peer qualities.
CONCLUSIONS: Improving medication for opioid use disorder outcomes is a national priority that must be met with cost-effective, sustainable strategies to support individuals in treatment. Findings will guide adaptation of a peer recovery specialist-delivered behavioral activation intervention to improve methadone treatment retention for underserved, ethno-racial minoritized individuals living with opioid use disorder
The writing on the wall: the concealed communities of the East Yorkshire horselads
This paper examines the graffiti found within late nineteenth and early-twentieth century farm buildings in the Wolds of East Yorkshire. It suggests that the graffiti were created by a group of young men at the bottom of the social hierarchy - the horselads – and was one of the ways in which they constructed a distinctive sense of communal identity, at a particular stage in their lives. Whilst it tells us much about changing agricultural regimes and social structures, it also informs us about experiences and attitudes often hidden from official histories and biographies. In this way, the graffiti are argued to inform our understanding, not only of a concealed community, but also about their hidden histor
New chiral organosulfur donors related to bis(ethylenedithio)tetrathiafulvalene
Six new enantiopure chiral organosulfur donors, with structures related to BEDT-TTF, have been synthesised for use in the preparation of organic metals, starting either by double nucleophilic substitutions on the bis-mesylate of 2R,4Rpentane-2,4-diol or by a cycloaddition with subsequent elimination of acetic acid on the enol acetate of (+)-nopinone. Crystal structures of some of their radical cation triiodides salts and TCNQ complexes are reported
Conductive Education as a Method of Stroke Rehabilitation: A Single Blinded Randomised Controlled Feasibility Study
Background. Conductive Education for stroke survivors has shown promise but randomised evidence is unavailable. This study assessed the feasibility of a definitive randomised controlled trial to evaluate efficacy. Methods. Adult stroke survivors were recruited through local community notices. Those completing the baseline assessment were randomised using an online program and group allocation was independent. Intervention group participants received 10 weekly 1.5-hour sessions of Conductive Education at the National Institute of Conductive Education in Birmingham, UK. The control group participants attended two group meetings. The study evaluated the feasibility of recruitment procedures, delivery of the intervention, retention of participants, and appropriateness of outcome measures and data collection methods. Independent assessments included the Barthel Index, the Stroke Impact Scale, the Timed Up and Go test, and the Hospital Anxiety and Depression Scale. Results. Eighty-two patients were enrolled; 77 completed the baseline assessment (46 men, mean age 62.1 yrs.) and were randomised. 70 commenced the intervention () or an equivalent waiting period (). 32/37 completed the 10-week training and 32/33 the waiting period. There were no missing items from completed questionnaires and no adverse events. Discussion. Recruitment, intervention, and assessment methods worked well. Transport issues for intervention and assessment appointments require review. Conclusion. A definitive trial is feasible. This trial is registered with ISRCTN84064492
- …