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First Sagittarius A* Event Horizon Telescope Results. VIII. Physical Interpretation of the Polarized Ring
Get PDFIn a companion paper, we present the first spatially resolved polarized image of Sagittarius A* on event horizon scales, captured using the Event Horizon Telescope, a global very long baseline interferometric array operating at a wavelength of 1.3 mm. Here we interpret this image using both simple analytic models and numerical general relativistic magnetohydrodynamic (GRMHD) simulations. The large spatially resolved linear polarization fraction (24%–28%, peaking at ∼40%) is the most stringent constraint on parameter space, disfavoring models that are too Faraday depolarized. Similar to our studies of M87*, polarimetric constraints reinforce a preference for GRMHD models with dynamically important magnetic fields. Although the spiral morphology of the polarization pattern is known to constrain the spin and inclination angle, the time-variable rotation measure (RM) of Sgr A* (equivalent to ≈46° ± 12° rotation at 228 GHz) limits its present utility as a constraint. If we attribute the RM to internal Faraday rotation, then the motion of accreting material is inferred to be counterclockwise, contrary to inferences based on historical polarized flares, and no model satisfies all polarimetric and total intensity constraints. On the other hand, if we attribute the mean RM to an external Faraday screen, then the motion of accreting material is inferred to be clockwise, and one model passes all applied total intensity and polarimetric constraints: a model with strong magnetic fields, a spin parameter of 0.94, and an inclination of 150°. We discuss how future 345 GHz and dynamical imaging will mitigate our present uncertainties and provide additional constraints on the black hole and its accretion flow
Performance of green high-strength concrete incorporating palm oil fuel ash in harsh environments
Get PDFThe corrosion of steel reinforcement by chloride is commonly recognized as a key factor that contributes to the degradation of durability in reinforced concreae structures. Using supplementary cementitious materials, such as industrial and agricultural waste materials, usually enhances the impermeability of the concrete and its corrosion resistance, acid resistance, and sulfate resistance. This study’s primary purpose is to examine the effects of replacing ordinary Portland cement (OPC) with ultrafine palm oil fuel ash (U-POFA) on the corrosion resistant performance of high-strength green concrete (HSGC). There were four HSGC mixes tested; the first mix contained 100% OPC, while the other mixes replaced OPC mass with 20%, 40%, and 60% of U-POFA. The performance of all HSGC mixes containing U-POFA on workability, compressive strength, porosity, water absorption, impressed voltage test, and mass loss was investigated at 7, 28, 60, and 90 days. Adding U-POFA to mixes enhances their workability, compressive strength (CS), water absorption, and porosity in comparison with mixes that contain 100% OPC. The findings clearly portrayed that the utilization of U-POFA as a partial alternative for OPC significantly enhances the corrosion-resistant performance of the HSGC. In general, it is strongly advised that a high proportion of U-POFA be incorporated, totaling 60% of the OPC content. This recommendation is the result of its significance as an environmentally friendly and cost-effective green pozzolanic material. Hence, it could contribute to the superior durability performance of concrete structures, particularly in aggressive environmental exposures. Highlights: The corrosion resistance performance of high-strength green concrete was investigated. Ultrafine palm oil fuel ash as a partial alternative of cement mass with 20%, 40%, and 60% was used. HSGC performance was evaluated in terms of workability, compressive strength, water absorption, porosity, impact stress testing, and mass loss
Synthesis, in silico and kinetics evaluation of N-(β-D-glucopyranosyl)-2-arylimidazole-4(5)-carboxamides and N-(β-D-glucopyranosyl)-4(5)-arylimidazole-2-carboxamides as glycogen phosphorylase inhibitors
Get PDFRecently studied N-(β-D-glucopyranosyl)-3-aryl-1,2,4-triazole-5-carboxamides proved to be low micromolar inhibitors of glycogen phosphorylase (GP), a validated target for the treatment of type 2 diabetes mellitus. Since in other settings, the bioisosteric replacement of the 1,2,4-triazole moiety by imidazole resulted in significantly more efficient GP inhibitors, in silico calculations using Glide molecular docking along with unbound-state DFT calculations was performed on N-(β-D-glucopyranosyl)-arylimidazole-carboxamides revealing potential for strong GP inhibition. The syntheses of the target compounds involved formation of an amide bond between per-O-acetylated β-D-glucopyranosylamine and the corresponding arylimidazole-carboxylic acids. Kinetics experiments against rabbit muscle GPb revealed low micromolar inhibitors with the best inhibition constants (Kis) of ~ 3-4 µM obtained for 1- and 2-naphthyl substituted N-(β-D-glucopyranosyl)-imidazolecarboxamides, 2b-c. The predicted protein-ligand interactions responsible for the observed potencies are discussed and will facilitate the structure-based design of other inhibitors targeting this important therapeutic target. Meanwhile, the importance of careful consideration of ligand tautomeric states in binding calculations is highlighted, with the usefulness of DFT calculations in this regard proposed
Efficacy and safety of Bowel Preparation Strategies in Inflammatory Bowel Disease Patients Undergoing Colonoscopy: A Systematic Review and Meta-Analysis
No full textAims The ESGE guidelines recommend high or low volume PEG-based bowel preparation for inflammatory bowel disease (IBD).[1] Recently available, non-PEG sulphate-based options provide additional choices. This systematic review meta-analysed efficacy and safety of bowel preparations for IBD patients undergoing colonoscopy
Methods We searched CENTRAL, ClinicalTrials.gov, Embase via Ovid, MEDLINE via Ovid, WHO ICTPR for RCTs until October 2023, covering all preparation types. Primary outcomes included bowel preparation success, tolerability, willingness to repeat, and safety. Secondary outcomes were caecal intubation rates (CIR) and abnormal serum electrolyte levels. Pooled estimates used risk ratio (RR) and 95% confidence interval (CI). GRADE assessed evidence certainty.
Results Ten RCTs(1479 IBD patients) were included, which compared 4L-PEG, with/without simethicone, castor oil vs. senna, two commercial low-volume PEG-based preparations, 2L PEG vs. 4L PEG, and low-volume PEG with additives vs. non-PEG-based preparations. For 2L vs. 4L PEG, bowel prep success showed no difference (RR 0.95,95% CI:0.88-1.09;I2=33%,2 RCTs;high certainty evidence). Willingness to repeat favored 2L (RR 0.69,95% CI:0.59-0.80; I2=18%,2 RCTs;high certainty evidence). In low-volume non-PEG vs. PEG, bowel prep success probably equaled (RR 0.96,95% CI:0.90-1.01;I2=6%,3 RCTs;moderate certainty evidence). Tolerability and willingness to repeat evidence was very uncertain (RR 0.81,95% CI:0.67-0.99;I2=76%,3 RCTs; very-low certainty evidence), (RR 0.77,95% CI:0.59-0.99; I2=83%,3 RCTs;very-low certainty evidence). No difference in CIR (RR 0.98,95% CI:0.93-1.03;I2=0%,2 RCTs;high certainty evidence). No abnormal post-bowel preparation electrolyte levels were noted in either group. Sub-group analysis showed comparable effectiveness of picosulphate-based (RR 0.89,95% CI:0.78-1.01;I2=0%,1 RCT) and sulphate-based preparations (RR 0.96,95% CI: 0.90-1.05;I2=28%,2 RCTs) compared to low-volume PEG-based preparations. Similar trends were noted for tolerability (RR 0.86,95% CI: 0.73-1.01;I2=22%,1 RCT with picosulphate-based, and RR 0.76,95% CI:0.45-1.26; I2=91%,2 RCTs with sulphate-based vs. low-volume PEG-based,respectively) and willingness to repeat (RR 0.62,95% CI:0.33-1.16;I2=86%,1 RCT with picosulphate-based, and RR 0.88,95% CI:0.65-1.20;I2=86%,2 RCTs with sulphate-based vs. low-volume PEG-based, respectively). Safety data were inconsistently reported.
Conclusions High-certainty evidence from two trials supports low-volume PEG with additives as comparably successful to high-volume PEG, with increased willingness to repeat. Moderate-certainty evidence from three trials indicates similar success between non-PEG-based and PEG-based preparations. Both low-volume PEG-based and non-PEG-based preparations have evidence supporting their clinical utility for IBD patients, expanding choices beyond ESGE 2019 guidelines
Where Food Safety Systems and Culture Collide: Do You Know Your Company's Psychosocial Risks?
No full textPsychosocial risks become important to food safety when they have the potential for causing psychological or physical harm, and when they lead to deficiencies in expected food safety behaviors
Impact of exercise training and diet therapy on the physical fitness, quality of life, and immune response of people living with HIV/AIDS: a randomized controlled trial
Get PDFBackground: Exercise and dietary nutrition are considered crucial in human immunodeficiency virus (HIV)/ acquired immunodeficiency syndrome (AIDS) treatment protocols and people living with HIV/AIDS (PLWHA) rehabilitation care. However, there is no well-studied research evaluating the effects of combined interventions on the fitness and immune systems of PLWHA. Therefore, this study aimed to analyze the effects of exercise and dietary intervention on physical fitness, quality of life and immune response in PLWHA. Methods: This was an experimental study, with a sample of 25 male PLWHA divided into two groups: the intervention group (IG: 12 participants) and the control group (CG: 13 participants). All participants have not had any exercise habits and nutritional supplements in the past six months. The participants in the IG completed 45 min of exercise (60-80% HRmax) 4 times per week for 4 weeks. The exercise was in the form of brisk walking or running. They were also given a nutritional dietary supplement 3 times a day for 4 weeks. The 13 individuals in the CG continued their normal daily life (physical activity and diet). The following parameters were evaluated before and after the intervention: body composition, physical fitness, immune response, quality of life (QoL), stress, dietary behavior, dietary habits, exercise motivation, and physical self-efficacy. Results: The significant changes were observed in burnout of stress variables and physical efficiency index (PEI) of physical fitness in the IG (p =.023). Moreover, in the saliva samples, sal-T levels significantly increased only after the intervention in the IG (p =.012). Additionally, regarding the analysis of the interaction (group × time), there was a significant improvement in the reaction speed (p =.001) and grip strength (left: p =.002, right: p =.030) and a significant difference in physical satisfaction in QoL (p =.001), stress burnout (p =.043), self-confidence in physical efficacy (p =.045), external display (p =.008), and fulfillment (p =.047) in exercise motivation. Moreover, the significant effect of the intervention on emotional eating in dietary behavior was shown in the comparison of the IG before and after intervention (p =.001) and in the comparison of the IG group with the CG after the experiment (p =.013). However, there was no significant effect of time or interaction between the condition and time on body composition. Conclusions: In conclusion, exercise training and diet therapy caused changes in physical fitness and Sal-T levels, which had positive effects on the health promotion of PLWHA
Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training
Get PDFObjective
In this investigation, we addressed the contribution of the core circadian clock factor, BMAL1, in skeletal muscle to both acute transcriptional responses to exercise and transcriptional remodeling in response to exercise training. Additionally, we adopted a systems biology approach to investigate how loss of skeletal muscle BMAL1 altered peripheral tissue homeostasis as well as exercise training adaptations in iWAT, liver, heart, and lung of male mice.
Methods
Combining inducible skeletal muscle specific BMAL1 knockout mice, physiological testing and standardized exercise protocols, we performed a multi-omic analysis (transcriptomics, chromatin accessibility and metabolomics) to explore loss of muscle BMAL1 on muscle and peripheral tissue responses to exercise.
Results
Muscle-specific BMAL1 knockout mice demonstrated a blunted transcriptional response to acute exercise, characterized by the lack of upregulation of well-established exercise responsive transcription factors including Nr4a3 and Ppargc1a. Six weeks of exercise training in muscle-specific BMAL1 knockout mice induced significantly greater and divergent transcriptomic and metabolomic changes in muscle. Surprisingly, liver, lung, inguinal white adipose and heart showed divergent exercise training transcriptomes with less than 5% of ‘exercise-training’ responsive genes shared for each tissue between genotypes.
Conclusions
Our investigation has uncovered the critical role that BMAL1 plays in skeletal muscle as a key regulator of gene expression programs for both acute exercise and training adaptations. In addition, our work has uncovered the significant impact that altered exercise response in muscle and its likely impact on the system plays in the peripheral tissue adaptations to exercise training. Our work also demonstrates that if the muscle adaptations diverge to a more maladaptive state this is linked to increased gene expression signatures of inflammation across many tissues. Understanding the molecular targets and pathways contributing to health vs. maladaptive exercise adaptations will be critical for the next stage of therapeutic design for exercise mimetics
Enhancing Academic Support for Students in Higher Education
Get PDFPurpose: The need to enhance student support is evident in higher education (HE) curricula. In addition to the complications created by the COVID-19 pandemic, the current strategies used in academia are criticised for their lack of appropriate student support in HE. The study focused on the themes under section four of the National Student Survey (NSS): availability to contact tutors, receiving good advice and guidance, and availability of good advice. The study aimed to provide recommendations for enhancing academic support by developing drivers that need implementation during course delivery.
Methodology: A documental analysis and a qualitative survey were adopted for this study. A documental analysis of 334 mid-module reviews (MMRs) from levels three to six students in the Built Environment (BE) discipline. Critical themes identified from the MMRs were fed forward in developing a questionnaire for academics. A sample of 23 academics, including a Head of school, a Principal lecturer, Subject leads and lecturers, participated in the questionnaire survey. Content analysis is adopted through questionnaire data to develop drivers to enhance academic support in BE. These drivers are then modelled by Interpretive Structural Modelling (ISM) to identify their correlation to NSS section four themes. A level partition analysis establishes how influential they are in enhancing academic support.
Findings: The study identified nine drivers, two categorised as fundamental, two as significant, four as important, and one insignificant in enhancing academic support in HE. Module leaders'/tutors' improving awareness and detailing how academic support is provided were identified as fundamental. Differentiating roles in giving advice and the importance of one-to-one meetings were identified as significant. A level partitioning diagram was developed from the nine drivers to illustrate how these drivers need to be implemented to promote the best practices in academic support in HE.
Practical implications: The identified drivers and their categories can be used to set prioritised guidelines for academics and other educational institutions to improve students’ overall satisfaction.
Originality/Value: Novelty from the study will be the developed drivers and the level partitioning diagram to assist academics and academic institutions in successfully integrating academic support into HE curricula