115 research outputs found

    Time-resolved spectroscopy studies of the photodeprotection reactions of p-hydroxyphenacyl ester phototrigger compounds

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    Ultrafast time-resolved spectroscopy and time-resolved resonance Raman spectroscopy experimental results in the picoseocond timescales are reported for selected p-hydroxyphenacyl (pHP) ester phototrigger compounds. The results better elucidate the photodeprotection and rearrangement reactions of these important phototriggers and an overall mechanism is proposed for these reactions based on the time-resolved spectroscopy data presented here. This work indicates that site-specific, concerted solvation of the hydroxy proton and phosphate-leaving anion group through their respective intermolecular H-bonding with solvent water molecules promotes the photodeprotection reaction.published_or_final_versio

    Development and validation of creatinine-based estimates of the Glo- Merular Filtration rate equation from Chromium Edta Imaging in the multi-racial Malaysian population

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    Background Glomerular filtration rate (GFR) is a reliable parameter for assessing kidney function. It is estimated from equations such as Cockcroft–Gault (CG), Modification of Diet in Renal Disease (MDRD), and Chronic Kidney Disease- Epidemiology Collaboration (CKD-EPI). However, these equations were derived using Western population demo- graphic data and had different performances when applied to other populations. Objectives. We developed a new equation (NE) based on the 51Cr EDTA measured GFR that can be used explicitly in the Malaysian multiracial population. Methods This was a cross-sectional study using the Electronic Medical Record (EMR) of pa- tients who underwent 51Cr-EDTA imaging at the Nuclear Medicine Centre, University Malaya Medical Centre (UMMC), from 2013 to 2021. This study had obtained approval from the Medical Research Ethics Committee, UMMC. Results Total data of 209 patients were recruited in this study. 105 were randomised in the development cohort, while 104 were in the validation cohort. A NE was developed based on data in the development cohort and then tested its performance in the validation cohort. The result showed that CKD-EPI had the highest correlation to 51Cr EDTA imaging measured GFR (r-value 0.82), followed by the NE (r-value 0.76). CG had the lowest bias (mean bias of 2.49), followed by the NE (mean bias of 3.52). CKD-EPI had the highest precision in estimating GFR (SD of 22.04ml/min), followed by the NE (SD of 25.05ml/min). CKD-EPI also had the highest accuracy (85.58% in P30 and 100% in P50, followed by MDRD (81.73% in P30 and 96.15% in P50). Conclusion The NE was less accurate than CKD-EPI and MDRD equation but generally has a rel- atively low bias of 3.52 ml/min. The limitation of the small sample size may limit the accuracy of the NE. Future studies with a larger sample size are needed to generate a more robust equation

    Cumulative Low Back Load at Work as a Risk Factor of Low Back Pain: A Prospective Cohort Study

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    Purpose Much research has been performed on physical exposures during work (e.g. lifting, trunk flexion or body vibrations) as risk factors for low back pain (LBP), however results are inconsistent. Information on the effect of doses (e.g. spinal force or low back moments) on LBP may be more reliable but is lacking yet. The aim of the present study was to investigate the prospective relationship of cumulative low back loads (CLBL) with LBP and to compare the association of this mechanical load measure to exposure measures used previously. Methods The current study was part of the Study on Musculoskeletal disorders, Absenteeism and Health (SMASH) study in which 1,745 workers completed questionnaires. Physical load at the workplace was assessed by video-observations and force measurements. These measures were used to calculate CLBL. Furthermore, a 3-year follow-up was conducted to assess the occurrence of LBP. Logistic regressions were performed to assess associations of CLBL and physical risk factors established earlier (i.e. lifting and working in a flexed posture) with LBP. Furthermore, CLBL and the risk factors combined were assessed as predictors in logistic regression analyses to assess the association with LBP. Results Results showed that CLBL is a significant risk factor for LBP (OR: 2.06 (1.32-3.20)). Furthermore, CLBL had a more consistent association with LBP than two of the three risk factors reported earlier. Conclusions From these results it can be concluded that CLBL is a risk factor for the occurrence of LBP, having a more consistent association with LBP compared to most risk factors reported earlier. © 2012 The Author(s)

    Intricate Correlation between Body Posture, Personality Trait and Incidence of Body Pain: A Cross-Referential Study Report

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    OBJECTIVE: Occupational back pain is a disorder that commonly affects the working population, resulting in disability, health-care utilization, and a heavy socioeconomic burden. Although the etiology of occupational pain remains largely unsolved, anecdotal evidence exists for the contribution of personality and posture to long-term pain management, pointing to a direct contribution of the mind-body axis. In the current study, we have conducted an extensive evaluation into the relationships between posture and personality. METHOD: We have sampled a random population of 100 subjects (50 men and 50 women) in the age range of 13-82 years based on their personality and biomechanical profiles. All subjects were French-Canadian, living in Canada between the Québec and Sorel-Tracy areas. The Biotonix analyses and report were used on the subjects being tested in order to distinguish postural deviations. Personality was determined by using the Myers-Briggs Type Indicator questionnaire. RESULTS: We establish a correlation between ideal and kyphosis-lordosis postures and extraverted personalities. Conversely, our studies establish a correlative relationship between flat back and sway-back postures with introverted personalities. CONCLUSION: Overall, our studies establish a novel correlative relationship between personality, posture and pain

    The flight feather moult pattern of the bearded vulture (Gypaetus barbatus).

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    Moult is an extremely time-consuming and energy-demanding task for large birds. In addition, there is a trade-off between the time devoted to moulting and that invested in other activities such as breeding and/or territory exploration. Moreover, it takes a long time to grow a long feather in large birds, and large birds that need to fly while moulting cannot tolerate large gaps in the wing, but only one or two simultaneously growing feathers. As a consequence, large birds take several years to complete a full moult cycle, and they resume the moult process during suboptimal conditions. A clear example of this pattern is the Bearded Vulture (Gypaetus barbatus), which needs 2-3 years for changing all flight feathers. Here we describe the sequence, extent, and timing of moult of 124 Bearded Vultures in detail for the first time. We found that extent and timing of flight feather moult was different between age classes. Subadults (from 3rd to 5th calendar year) started moult, on average, in early March, whereas adults only started moult, on average, in late April, possibly due to breeding requirements. Second calendar year individuals delayed onset of moult until the middle of May. In general, the moult lasted until November, and although adults started to moult later than subadults, they moulted more feathers. Subadults needed 3 years for moulting all flight feathers, whereas adults normally completed it in 2 years

    Intrapersonal and interpersonal dimensions of cancer perception: a confirmatory factor analysis of the cancer experience and efficacy scale (CEES)

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    Purpose Sociocultural factors influence psychological adjustment to cancer in Asian patients in two major ways: Prioritization of relationships over individual orientations and belief in the efficacy of interpersonal cooperation. We derived and validated among Chinese colorectal cancer (CRC) patients an instrument assessing cancer perceptions to enable the study of the sociocultural processes. Patients and methods Qualitative interviews (n=16) derived 15 items addressing interpersonal experience in Chinese CRC patients' adjustment. These 15 items and 18 corresponding self-referent items were administered to 166 Chinese CRC survivors and subjected to exploratory factor analysis (EFA) to establish the initial scale structure and reliability. The final 29 items, together with other psychometric measures, were administered to a second cohort of 215 CRC patients and subjected to confirmatory factor analysis (CFA). Results EFA (63.35% of the total variance) extracted six factors: Personal strain, socioeconomic strain, emotional strain, personal efficacy, collective efficacy, and proxy efficacy. CFA confirmed the psychometric structure [?2(df)=702.91 (368); Comparative Fit Index=0.95; Nonnormed Fit Index= 0.94; Incremental Fit Index=0.95; standardized root mean square residual=0.08] of the six factors by using a model with two latent factors: Experience and efficacy. All subscales were reliable (a=0.76-0.92). Appropriate correlations with adjustment outcomes (symptom distress, psychological morbidity, and subjective well-being), optimistic personalities, and social relational quality indicated its convergent and divergent validity. Known group comparisons (i.e., age, active treatment, and colostomy) showed its clinical utility. Conclusion The cancer experience and efficacy scale is a valid multidimensional instrument for assessing intrapersonal and interpersonal dimensions of cancer experience in Asian patients, potentiating existing patient-reported outcome measures. © Springer-Verlag 2009.published_or_final_versionSpringer Open Choice, 01 Dec 201

    Dimerization of Hepatitis E Virus Capsid Protein E2s Domain Is Essential for Virus–Host Interaction

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    Hepatitis E virus (HEV), a non-enveloped, positive-stranded RNA virus, is transmitted in a faecal-oral manner, and causes acute liver diseases in humans. The HEV capsid is made up of capsomeres consisting of homodimers of a single structural capsid protein forming the virus shell. These dimers are believed to protrude from the viral surface and to interact with host cells to initiate infection. To date, no structural information is available for any of the HEV proteins. Here, we report for the first time the crystal structure of the HEV capsid protein domain E2s, a protruding domain, together with functional studies to illustrate that this domain forms a tight homodimer and that this dimerization is essential for HEV–host interactions. In addition, we also show that the neutralizing antibody recognition site of HEV is located on the E2s domain. Our study will aid in the development of vaccines and, subsequently, specific inhibitors for HEV
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