Pool Size Research Articles

Immune reconstitution and evolution of B-cell–stimulating cytokines after R-CHOP therapy for HIV-associated DLBCL

AbstractHIV infection is associated with an increased risk of diffuse large B-cell lymphoma (DLBCL) that persists despite the advent of combined antiretroviral therapy. In this prospective study, we analyzed the evolution of B-cell activating cytokines (interleukin-6 [IL-6], IL-10, and B-cell activating factor [BAFF]) and the coevolution of main functional subsets of circulating B and T cells in 51 patients with HIV-associated DLBCL treated with R-CHOP (rituximab, cyclophosphamide, doxorubicin, Oncovin [vincristine], and prednisone). R-CHOP therapy was associated with a decrease of IL-10, whereas IL-6 levels fluctuated, and BAFF levels increased during the first 3 months and decreased thereafter. We observed a rapid rise in CD19+ B cells composed mostly of naïve B cells whereas marginal zone–like B cells and memory B cells recovered gradually. With a median follow-up of 41 months, progression-free survival and overall survival at 5 years were 61.8% (95% confidence interval [CI], 47.6-80.4) and 67.4% (95% CI, 53.4-85.0), respectively. Progression (17.5%) and sepsis (12.5%) were the main causes of death. Baseline risk factors for death and progression were poor revised International Prognostic Index (P = .049), natural killer cell lymphopenia (P = .001), lower proportion of naïve B cells among B-cell compartment (P = .017), and higher IL-6 serum levels (P = .001). Our data suggest that patients treated with R-CHOP for HIV-associated DLBCL have a disturbed peripheral B-cell compartment and that the low pool size of circulating naïve B cells negatively affects clinical outcome in these patients. In an era of rapid development of B-cell–depleting therapies including B-cell–targeting chimeric antigen receptor T cells, baseline and posttreatment assessment of perturbations within nontumoral B-cell counterparts are warranted for proper risk profiling in HIV-associated DLBCL. This trial was registered at www.ClinicalTrials.gov as #NCT01164436.

Model the evolutionary pattern of N species and pool size in groundwater continuum by utilizing measured source and sink rates of nitrate and ammonium

Nitrate and ammonium are primary nitrogen (N) contaminants in groundwater and effective restoration strategies depend on understanding the interactions of N transformation processes along redox gradients. Utilizing the 15N tracing technique, we assess nitrate removal rates, focusing on denitrification and anammox in a N-rich groundwater of the Hetao Basin, a typical semiarid region in western China. Results showed that N removal rate (0.36–22.01 µM N d−1) was composed mainly of denitrification (73 ± 18 %), with rates increasing from upstream oxidizing environment to downstream reducing areas. In reducing downstream, both denitrification and anammox adhered to substrate-driven Michaelis-Menten kinetics. Integrating data on all source and sink rates of nitrate and ammonium pools (denitrification, anammox, dissimilatory nitrate reduction ammonia, nitrification, mineralization), we constructed a N-transfer-dynamics model based on chemical stoichiometry. This model effectively captured the observed spatial N transfer patterns and highlighted that the balance of oxidants and biodegradable organic N inputs influences N species retention and removal in groundwater. Our combined experimental and modeling approach underscores the importance of reducing organic N and/or adding oxidants to mitigate groundwater N pollution. These findings provide crucial insights for optimizing high N groundwater remediation strategies and potentially inform for wastewater management practices.

Slower but deeper community change: Intrinsic dynamics regulate anthropogenic impacts on species temporal turnover.

Understanding the mechanisms behind biodiversity dynamics is central to assessing and forecasting anthropogenic impacts on ecological communities. However, the manner in which external environmental drivers act in concert with intrinsic ecological processes to influence local temporal turnover is currently largely unexplored. Here, we determine how human impacts affect multiple metrics of bird community turnover to establish the ecological mechanisms behind compositional change. We used US Breeding Bird Survey data to calculate transect-level rates of three measures of temporal species turnover: (1) "short-term" (initial rate of decline of Sørensen similarity), (2) "long-term" (asymptotic Sørensen similarity), and (3) "throughput" (overall species accumulation rate from species-time relationship exponents) over 2692 transects across 27 regional habitat types. We then hierarchically fit linear models to estimate the effect of anthropogenic impact on these turnover metrics, using the Human Modification Index proxy, while accounting for observed species richness, the size of the species pool, and annual environmental variability. We found broadly consistent impacts of increased anthropogenic pressures across diverse habitat types. The Human Modification Index was associated with greater turnover at long timescales, but marginally slower short-term turnover. The species "throughput" (accumulation rate) was not notably influenced. Examining anthropogenic impacts on different aspects of species turnover in combination allows greater ecological insight. Observed human impacts on short-term turnover were the opposite of existing expectations and suggest humans are disrupting the background turnover of these systems, rather than simply driving rapid directed turnover. The increased long-term turnover without concurrent increases in species accumulation implies human impacts lead to shifts in species occurrence frequency rather than simply greater arrival of "new" species. These results highlight the role of intrinsic dynamics and caution against simple interpretations of increased species turnover as reflections of environmental change.

Reactive Immunomodulator Addition to Infliximab Monotherapy Restores Clinical Response in Inflammatory Bowel Disease: A Meta-Analysis.

Patients with inflammatory bowel disease (IBD) receiving infliximab (IFX) commonly experience immunogenic loss of response (LOR) by formation of anti-drug antibodies (ADAs). An immunomodulator (IMM) used in combination with initial IFX induction is known to reduce ADA development and improve clinical outcomes. We aimed to assess the impact of reactively adding an IMM to patients on IFX monotherapy. We conducted a retrospective cohort study and systematic review with meta-analysis of patients with IBD demonstrating immunologic LOR, with or without clinical LOR, that had an IMM (azathioprine, 6-mercaptopurine, or methotrexate) reactively added (reactive combination therapy; rCT) to combat elevated ADAs and raise IFX level. Data were extracted for pooled effect size estimation using random-effects models, and ADA and IFX trough levels were compared pre- and post-IMM initiation. We identified 6 patients who received rCT due to rising ADA titers and low IFX levels. Median ADA titer decreased from 506ng/mL (interquartile range (IQR) [416-750]) to 76.5ng/mL (IQR [25.8-232]), an 85% decrease (p = 0.031). Median IFX trough increased from 0.4µg/mL (IQR [0.4-0.48]) to 8.25µg/mL (IQR [3.7-9.6]), a 20.6-fold increase (p = 0.038). Meta-analysis pooled effect size of 7 studies with 89 patients showed an 87% ADA titer reduction [95% confidence interval (CI) = 72-94%], 6.7-fold increased IFX trough (95% CI = 2.4-18.7), and 76% clinical remission rescue rate (95% CI = 59-93%). These results suggest rCT is a valid rescue strategy in patients with immunogenic LOR to IFX to reduce ADA titers, restore therapeutic IFX levels, and recapture clinical remission of IBD.

Frequency-dependent returns in nonlinear public goods games.

When individuals interact in groups, the evolution of cooperation is traditionally modelled using the framework of public goods games. These models often assume that the return of the public goods depends linearly on the fraction of contributors. In contrast, in real-life public goods interactions, the return can depend on the size of the investor pool as well. Here, we consider a model in which the multiplication factor (marginal per capita return) for the public goods depends linearly on how many contribute, which results in a nonlinear model of public goods. This simple model breaks the curse of dominant defection found in linear public goods interactions and gives rise to richer dynamical outcomes in evolutionary settings. We provide an in-depth analysis of the more varied decisions by the classical rational player in nonlinear public goods interactions as well as a mechanistic, microscopic derivation of the evolutionary outcomes for the stochastic dynamics in finite populations and in the deterministic limit of infinite populations. This kind of nonlinearity provides a natural way to model public goods with diminishing returns as well as economies of scale.

Investigating temperature, stress, and residual stresses in laser powder bed fusion additive manufacturing of Inconel 625

Laser powder bed fusion (LPBF) is a pivotal method in metal additive manufacturing, enabling the intricate fabrication of complex components. However, the rapid thermal transitions inherent in LPBF can induce residual stresses, potentially leading to defects like distortions, cracks, and delamination. This research aims to investigate the distribution of temperature and stress during the LPBF manufacturing of Inconel 625, as well as the generation of residual stresses. For this purpose, a three-dimensional finite element (FE) model of the LPBF process was developed to explore the influence of various factors, including the number of layers, deposition region dimensions, and layer thicknesses, on temperature and stress distribution. Additionally, the study thoroughly examined the residual stress occurred on the part related to post-cooling and their variations after substrate separation. The outcomes reveal that the dimension of the deposition region significantly impacts both temperature and the size of the melt pool. The melt pool depth of 91 μm was calculated from the FE models, closely aligning with the experimentally measured value of 84.7 μm. Furthermore, the separation of the substrate has a notable effect on the distribution of residual stresses in the LPBF specimen. For instance, the residual stress at the center of the first layer decreased from 818 MPa after the cooling process to 108 MPa following substrate separation.

Effects of Aerobic Exercise on Vascular Wall Thickness: A Meta-Analysis of Pre-Clinical Trials on Rat Model.

Exercise instigates adaptations in structural as well as functional organisation of the body at tissue and organ levels. However, the effect of exercise on vascular wall morphology is still under investigation. The objective of the review is to provide a meta-analysis of data from the previously published research to provide compiled analysis to determine the effect of exercise on the thickness of large-sized vessel walls. This meta-analysis was executed at the Ziauddin College of Rehabilitation Sciences with an extensive literature search using databases and search engines such as Pubmed, CINAHL, Web of Science, Scopus, and Google Scholar between September 2022 and January 2023. Studies were appraised according to an estimate of mean difference and pooled effect size was calculated using a random effect model. The risk of bias was also calculated using SYRCLE's risk of bias tool and CAMARADES. Overall, five eligible pre-clinical trials using rat models with pertinent data to determine the effect of exercise on vessel wall thickness were included in the meta-analysis. The results showed that aerobic exercise significantly reduced the vessel wall thickness (SMD -0.854 5%; CI: -1.365 to -0.344; p <0.001). Moreover, no significant publication bias was found through funnel plot and statistical test (Egger's p = 0.276; Begg's p = 0.624). However, an extensive review of the literature currently available on the topic has shown mixed findings that are consistent with the study and vice versa. Therefore, it indicated the need for sub-group analysis with different types of exercises for more peculiar clinical approaches. Key Words: Morphometry, Animal studies meta-analysis, Media thickness, Physical activity, Vascular morphology.

Effectiveness of non-pharmacological interventions for pain management in patients with cancer:a protocol for systematic review and network meta-analysis

IntroductionPain management in patients with cancer is a critical aspect of oncological care, yet remains challenging with current pharmacological therapies. Non-pharmacological interventions, offering potential benefits without the adverse effects of...

On morphology and roughness of upskin surfaces in laser powder-bed fusion additive manufacturing – Contouring strategy effects

The surface quality of inclined parts made by Laser powder-bed fusion (L-PBF) additive manufacturing is inferior to those made by conventional formative and subtractive manufacturing techniques. The inherited step edges formed during such layer-by-layer fabrications and partially melted or non-melted particles attached to the newly formed surface are the major causes of poor surface finish of L-PBF parts. This study is a part of a research framework, in which the effects of different contouring strategies and scan parameters on the surface morphology of inclined parts are investigated by both experimental and numerical methods. In particular, the effect of two different contour scan strategies, namely pre-contouring and post-contouring, on the upskin surface roughness of 30⁰ inclined parts is analyzed. The inclined specimens were fabricated with Ti6Al4V powder using an EOS M270 system and the upskin surfaces were measured by a white light interferometer. In addition, a multi-track multi-layer numerical approach using coupled discrete element method and thermo-fluid simulation was also performed to understand the inclined surface formation in L-PBF.The findings show that the pre-contouring strategy with high linear energy density (LED) (0.4 J/mm) results in average surface roughness (Sa) as low as 7.43 µm, whereas the lowest LED (0.05 J/mm) resulted in the highest Sa of 33.74 µm. Larger melt pool dimensions were obtained in the high LED pre-contouring simulations, which indicates a better material fusion resulting in a good surface finish. The numerical simulation showed that the upskin surface roughness is also affected by the raster scan, if the raster scanning LED is higher than that of pre-contour scans. For the post-contouring strategy studied, higher and lower LEDs were used in inner and outer contour scanning, respectively. It is indicated that the inner contour scanning with a high LED reduces the surface roughness because of a larger melt pool size, irrespective of outer contour scanning. The lowest Sa obtained was 8.24 µm for the highest LED inner contour (0.05 J/mm) case and the highest Sa was 19.95 µm, for the parts made with the lowest LED inner contour scan (0.075 J/mm) strategy. The coupled discrete-element and thermo-fluid-based simulations offer insights into the sloped surface formation and the results supported the experimental findings in qualitative manner.

Metabolomics of related C3 and C4 Flaveria species indicate differences in the operation of photorespiration under fluctuating light.

C3 photosynthesis can be complemented with a C4 carbon concentrating mechanism (CCM) to minimize photorespiratory losses. C4 photosynthesis is often more efficient than C3 under steady-state conditions. However, the C4 CCM depends on inter-cellular metabolite concentration gradients, which must increase following increases in light intensity and could decrease rates of C4 photosynthesis under fluctuating light. Additionally, incomplete flux through photorespiration could prove beneficial to C4 assimilation during light induction of the CCM. Here, we compare metabolic profiles in the closely related C3 Flaveria robusta and C4 Flaveria bidentis during a light transient from low to high light to determine if these non-steady state accumulation patterns provide insight to the induction of the metabolite gradients needed to drive C4 intermediate transport and if there is incomplete cycling of photorespiratory intermediates. In these C3 and C4 species, metabolite steady-state pool sizes suggest that C4 transport acids maintain concentration gradients across the bundle sheath and mesophyll cell types under these light fluctuations. However, there was incomplete flux through photorespiration in the C4 F. bidentis, which could reduce photorespiratory CO2 loss via glycine decarboxylation and help maintain higher rates of assimilation during following induction periods.

Agricultural plastic pollution reduces soil function even under best management practices.

Soil plastic contamination is considered a threat to environmental health and food security. Plastic films-which are widely used as soil mulches-are the largest single source of agricultural plastic pollution. Growing evidence indicates that high concentrations of plastic negatively affect critical soil functions. However, the relationships between agricultural plastic accumulation and its biogeochemical consequences in regions with relatively low levels of soil plastic pollution remain poorly characterized. We sampled farms across the California Central Coast (a region of global agricultural importance with extensive plastic mulch-based production) to assess the degree and biogeochemical consequences of plastic pollution in fields subject to "best practice" plastic mulching application and removal practices over multiple years. All farms exhibited surface soil plastic contamination, macroplastic positively correlated with microplastic contamination levels, and macroplastic accumulation was negatively correlated with soil moisture, microbial activity, available phosphate, and soil carbon pool size. These effects occurred at less than 10% of the contamination levels reported to degrade field soils, but were relatively subtle, with no detectable relationship to microplastic concentration. Identifying declines in soil quality with low levels of macroplastic fragment accumulation suggests that we must improve best management plasticulture practices to limit the threat to soil health and agricultural productivity of unabated plastic accumulation.

Prevalence and associated factors of post-traumatic stress disorder in pediatric populations in Africa: a systematic review and meta-analysis

IntroductionPost-traumatic stress disorder (PTSD) is a prevalent challenge faced by individuals following traumatic events. Given the substantial impact of PTSD on the well-being of young people, comprehensive assessment of the available evidence can inform more effective prevention and intervention strategies to support the mental health and resilience of children in the African context. Despite its high incidence, there has been no up-to-date systematic synthesis of evidence to measure the magnitude of PTSD in pediatric populations in Africa. This systematic review and meta-analysis aim to quantify the prevalence of PTSD and identify associated factors in this vulnerable population.MethodsA systematic search was conducted across multiple databases, including PubMed, Embase, Scopus, Science Direct, and the search engines Google Scholar and Google, covering the period from 2014 up to May 15, 2024. The primary objective of this search was to identify relevant studies. Subsequently, a meta-analysis was performed using random-effects models to estimate the pooled effect size for each outcome of interest. Additionally, subgroup analysis was conducted to explore potential sources of heterogeneity, with study characteristics considered as covariates.ResultsThe pooled prevalence estimate for post-traumatic stress disorder (PTSD) among pediatric individuals was 36% (95% CI: 28–44%). Notably, significant heterogeneity existed among the studies (I2 = 98.41%, p value < 0.001), prompting us to employ a random effect model analysis. Furthermore, our meta-analysis revealed that children above 14 years of age and those who experienced family deaths due to traumatic events were significantly associated with PTSD.ConclusionThis systematic review and meta-analysis revealed that the prevalence of PTSD among pediatric individuals aged 0–18 years in Africa was high. Notably, older children and those who experienced family deaths due to traumatic events were at a significantly higher risk of developing PTSD. These findings underscore the need for early intervention, age-specific support, and trauma-informed care to address the mental health challenges faced by pediatric populations.

The Dietary Pattern Concerning Non-alcoholic Fatty Liver: An Umbrella Review and Meta-analyses of Observational Studies and Intervention Trials

Context: Non-alcoholic fatty liver disease (NAFLD) has been extensively studied in recent years, but the optimal dietary patterns for improving this condition remain unclear. Evidence Acquisition: Therefore, this umbrella review aimed to summarize the available evidence from meta-analyses on the relationship between various dietary patterns and NAFLD. Results: Two independent researchers identified published meta-analyses of interventional and observational studies that investigated the relationship between dietary patterns and NAFLD by searching electronic databases up until March 2023 and extracting relevant information. The pooled effect size of dietary patterns on NAFLD was evaluated using the standard mean difference (SMD) with a 95% confidence interval (CI). Fourteen meta-analyses met the inclusion criteria. Conclusions: All NAFLD-related outcomes, including hepatic steatosis, Fatty Liver Index (FLI), liver stiffness, and liver enzymes, were significantly affected by a calorie-restricted diet. Similarly, following the Mediterranean diet had beneficial effects on improving these outcomes. The findings support the role of a calorie-restricted diet and a Mediterranean diet in improving NAFLD, alongside the treatment protocol for these patients.

Assessment of the Effective Sensitivity of SARS-CoV-2 Sample Pooling Based on a Large-Scale Screening Experience: Retrospective Analysis.

The development of new large-scale saliva pooling detection strategies can significantly enhance testing capacity and frequency for asymptomatic individuals, which is crucial for containing SARS-CoV-2. This study aims to implement and scale-up a SARS-CoV-2 screening method using pooled saliva samples to control the virus in critical areas and assess its effectiveness in detecting asymptomatic infections. Between August 2020 and February 2022, our laboratory received a total of 928,357 samples. Participants collected at least 1 mL of saliva using a self-sampling kit and registered their samples via a smartphone app. All samples were directly processed using AutoMate 2550 for preanalytical steps and then transferred to Microlab STAR, managed with the HAMILTON Pooling software for pooling. The standard pool preset size was 20 samples but was adjusted to 5 when the prevalence exceeded 2% in any group. Real-time polymerase chain reaction (RT-PCR) was conducted using the Allplex SARS-CoV-2 Assay until July 2021, followed by the Allplex SARS-CoV-2 FluA/FluB/RSV assay for the remainder of the study period. Of the 928,357 samples received, 887,926 (95.64%) were fully processed into 56,126 pools. Of these pools, 4863 tested positive, detecting 5720 asymptomatic infections. This allowed for a comprehensive analysis of pooling's impact on RT-PCR sensitivity and false-negative rate (FNR), including data on positive samples per pool (PPP). We defined Ctref as the minimum cycle threshold (Ct) of each data set from a sample or pool and compared these Ctref results from pooled samples with those of the individual tests (ΔCtP). We then examined their deviation from the expected offset due to dilution [ΔΔCtP = ΔCtP - log2]. In this work, the ΔCtP and ΔΔCtP were 2.23 versus 3.33 and -0.89 versus 0.23, respectively, comparing global results with results for pools with 1 positive sample per pool. Therefore, depending on the number of genes used in the test and the size of the pool, we can evaluate the FNR and effective sensitivity (1 - FNR) of the test configuration. In our scenario, with a maximum of 20 samples per pool and 3 target genes, statistical observations indicated an effective sensitivity exceeding 99%. From an economic perspective, the focus is on pooling efficiency, measured by the effective number of persons that can be tested with 1 test, referred to as persons per test (PPT). In this study, the global PPT was 8.66, reflecting savings of over 20 million euros (US $22 million) based on our reagent prices. Our results demonstrate that, as expected, pooling reduces the sensitivity of RT-PCR. However, with the appropriate pool size and the use of multiple target genes, effective sensitivity can remain above 99%. Saliva pooling may be a valuable tool for screening and surveillance in asymptomatic individuals and can aid in controlling SARS-CoV-2 transmission. Further studies are needed to assess the effectiveness of these strategies for SARS-CoV-2 and their application to other microorganisms or biomarkers detected by PCR.

Comparison of the ability of resection versus nonresection surgery to prevent the recurrence of sigmoid volvulus: A protocol of a meta-analysis and systematic review.

Based on clinical research guidelines and clinical practice, patients with sigmoid volvulus (SV) who receive conservative treatment have a greater recurrence rate than patients who do not receive conservative treatment, which is almost without any controversy. Surgical treatment is usually the final treatment for patients with SV. However, there are multiple surgical methods for the treatment of SV, which can be roughly divided into resection and nonresection methods. The available evidence on the effectiveness of surgery for preventing postoperative recurrence is still inadequate. Therefore, we drafted this systematic review protocol with meta-analysis aimed to compare the effects of these two major types of surgery on preventing the recurrence of SV. We comprehensively and systematically reviewed the PubMed, EMBASE, MEDLINE and Cochrane Library databases of articles on SV from inception to November 16, 2023. Two independent authors will screen and analyze the detected literature, and disputes will be resolved through communication with a third experienced person. After evaluating the quality of the literature and estimating the risk of bias, we calculate the pooled effect size and 95% confidence interval. Heterogeneity is analyzed by subgroup analysis, and sensitivity analysis can be carried out to assure the reliability of the results. Finally, the Grading of Recommendations Assessment, Development and Evaluation (GRADE) will be used to evaluate the strength of the evidence. The results of each analysis will be recorded in detail. The whole process was carried out in strict accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols guidelines (PRISMA-P). Protocol registration: The study protocol has been registered at the International Prospective Register of Systematic Reviews platform (PROSPERO) (CRD42024508350). Protocol version 1.0, 13 Feb 2024.

Racism and health and wellbeing among children and youth–An updated systematic review and meta-analysis

BackgroundEvidence of racism's health harms among children and youth is rapidly increasing, though attention to impacts on physical health and biomarker outcomes is more emergent. We performed a systematic review of recent publications to examine the association between racism and health among children and youth, with a meta-analysis of the specific relationships between racism and physical health and biomarkers. MethodsWe conducted a systematic literature search using four databases: Medline, PsycINFO, PubMed, and ERIC. Four inclusion criteria were used to identify eligible studies: (1) exposure was experiences of racism, (2) outcome was health and wellbeing, (3) quantitative methods were used to estimate the association between racism and health outcomes, and (4) the effect size of associations between racism and health and wellbeing was reported for participants aged 0–24 years. Correlation coefficients were used to report the pooled effect size for each outcome indicator. ResultsThere were 463 eligible studies included in the screening process, with 42 studies focusing on physical health or biomarker outcomes. Random-effects meta-analysis found minimal to moderate positive associations between racism and C-reactive protein, Interleukin 6, body mass index (BMI), obesity, systolic blood pressure, salivary cortisol, asthma, and somatic symptoms. There were marginal positive associations between racism and Tumour Necrosis Factor-α, cortisol collected via saliva, urine and hair, BMI-z score, and diastolic blood pressure, with imprecise estimates and wide confidence intervals. ConclusionsRacism is associated with negative physical health and biomarker outcomes that relate to multiple physiological systems and biological processes in childhood and adolescence. This has implications for health and wellbeing during childhood and adolescence and future chronic disease risk. Collective and structural changes to eliminate racism and create a healthy and equitable future for all children and youth are urgently required.

Monitoring molecular events during photo-driven ubiquinone pool reduction in PufX+ and PufX− membranes from Rhobobacter capsulatus by time-resolved FTIR difference spectroscopy

The PufX protein is found in the photosynthetic membranes of several purple bacteria and is involved in ubiquinol-ubiquinone exchange at the QB site of the reaction center. We have studied quinone pool reduction in chromatophores from PufX+ and PufX− strains of Rhodobacter capsulatus by time-resolved FTIR difference spectroscopy under and after continuous illumination. To our knowledge, it is the first time that quinone pool reduction has been directly followed in real time in Rba. capsulatus membranes.Thanks to the availability in the literature of IR marker bands for protein conformational changes, ubiquinone consumption, ubiquinol production, Q---QH2 quinhydrone complex formation, as well as for RC-bound QA− and QB− semiquinone species, it is possible to follow all the molecular events associated with light-induced quinone pool reduction. In Rba. capsulatus PufX + chromatophores, these events resemble the ones found in Rba. sphaeroides wild-type membranes.In PufX− chromatophores the situation is different. Spectra recorded during 22.7 s of illumination showed a much smaller amount of photoreduced quinol, consistent with previous observations that PufX is required for efficient QH2/Q exchange at the QB site of the RC. Q consumption and QH2 formation are rapidly associated with QA− formation, showing that the structure of the RC-LH1 complex in PufX− membranes does not provide efficient access to the QB site of the RC to a large fraction of the quinone pool, evidently because the LH1 ring increases in size to impair access to the RC. The presence of a positive band at 1560 cm−1 suggests also the transient formation, in a fraction of chromatophores or of RC-LH1 complexes, of a Q---QH2 quinhydrone complex.Experiments carried out after 2-flash and 10-flash sequences make it possible to estimate that the size of the quinone pool with access to the QB site in PufX− membranes is ≥ 5 ubiquinone molecules per RC. The results are discussed in the framework of the current knowledge of protein organization and quinone pool reduction in bacterial photosynthetic membranes.

An aggregate matching and pick-up model for mobility-on-demand services

This paper presents an Aggregate Matching and Pick-up (AMP) model to delineate the matching and pick-up processes in mobility-on-demand (MoD) service markets by explicitly considering the matching mechanisms in terms of matching intervals and matching radii. With passenger demand rate, vehicle fleet size and matching strategies as inputs, the AMP model can well approximate drivers’ idle time and passengers’ waiting time for matching and pick-up by considering batch matching in a stationary state. Properties of the AMP model are then analyzed, including the relationship between passengers’ waiting time and drivers’ idle time, and their changes with market thickness, which is measured in terms of the passenger arrival rate (demand rate) and the number of active vehicles in service (supply). The model can also unify several prevailing inductive and deductive matching models used in the literature and spell out their specific application scopes. In particular, when the matching radius is sufficiently small, the model reduces to a Cobb–Douglas type matching model proposed by Yang and Yang (2011) for street-hailing taxi markets, in which the matching rate depends on the pool sizes of waiting passengers and idle vehicles. With a zero matching interval and a large matching radius, the model reduces to Castillo model developed by Castillo et al. (2017) that is based on an instant matching mechanism, or a bottleneck type queuing model in which passengers’ matching time is derived from a deterministic queue at a bottleneck with the arrival rate of idle vehicles as its capacity and waiting passengers as its customers. When both the matching interval and matching radius are relatively large, the model also reduces to the bottleneck type queuing model. The performance of the proposed AMP model is verified with simulation experiments.

Short- and long-term effects of concurrent aerobic and resistance training on circulating irisin levels in overweight or obese individuals: a systematic review and meta-analysis of randomized controlled trials.

Concurrent training (CT) is emerging as a practical and effective approach to enhance body composition, cardiovascular function, and muscle mass, thereby elevating overall individual health. This study aims to systematically investigate the effects of short- and long-term concurrent aerobic and resistance training on circulating irisin levels in overweight or obese individuals. The electronic databases, including China National Knowledge Infrastructure, PubMed, Embase, Wan Fang Database, and Web of Science, were systematically searched for articles on "concurrent training" and "irisin" published from their inception to 30 November 2023. The pooled effect size was determined using standardized mean difference (SMD) and corresponding 95% confidence intervals (CIs). The study protocol received registration with the International Prospective Register of Systematic Reviews (CRD42023494163). All nine studies, encompassing a total of 264 participants, were randomized controlled trials and met the eligibility criteria. Results indicate that short- and long-term concurrent training moderately increased circulating irisin levels compared to the control group (SMD = 0.56, 95% CI [0.33-0.80], p=0.00; I 2 = 36.6%, heterogeneity p=0.106). Subgroup analyses revealed that both equal to or less than 10 weeks (SMD = 0.78, 95% CI [0.18-1.37], p=0.01; I 2 = 62.3%, heterogeneity p=0.03) and more than 10 weeks (SMD = 0.45, 95% CI [0.14-0.76], p=0.00; I 2 = 0%, heterogeneity p=0.54) of concurrent training significantly increased circulating irisin levels in overweight or obese individuals. There were no significant between-group differences (I 2=0%, p=0.34). Additionally, concurrent training significantly increased irisin levels in overweight or obese participants (SMD = 1.06, 95% CI [0.34-1.78], p=0.00; I 2 = 50.6%, heterogeneity p=0.13) and in type 2 diabetes patients (SMD = 0.70, 95% CI [0.30-1.10], p=0.00; I 2 = 0%, heterogeneity p=0.99). However, no significant effect was observed in patients with metabolic syndrome (SMD = 0.21, 95% CI [-0.25-0.68], p=0.37; I 2 = 38.7%, heterogeneity p=0.18). There were significant between-group differences (I 2=53.9%, p=0.11). Lastly, concurrent training significantly increased circulating irisin levels in overweight or obese individuals aged 45-60 years (SMD = 0.56, 95% CI [0.25-0.86], p=0.00; I 2 = 6.5%, heterogeneity p=0.38), and a significant increase in irisin levels was observed 12 h post-intervention (SMD = 0.70, 95% CI [0.35-1.05], p=0.00; I 2 = 0%, heterogeneity p=0.74). However, none of the above categorical variables showed significant between-group differences. Short- and long-term concurrent training can effectively improve circulating irisin levels in overweight or obese individuals. However, the effects of short- and long-term concurrent training should consider the participants' health status, age, and the timing of post-exercise measurements to maximize health benefits.

The role of binocular disparity and attention in the neural representation of multiple moving stimuli in the visual cortex.

Segmenting visual scenes into distinct objects and surfaces is a fundamental visual process, with stereoscopic depth and motion serving as crucial cues. However, how the visual system uses these cues to segment multiple objects is not fully understood. We investigated how neurons in the middle-temporal (MT) cortex of macaque monkeys represent overlapping surfaces at different depths, moving in different directions. Neuronal activity was recorded from three male monkeys during discrimination tasks under varying attention conditions. We found that neuronal responses to overlapping surfaces showed a robust bias toward the binocular disparity of one surface over the other. The disparity bias of a neuron was positively correlated with the neuron's disparity preference for a single surface. In two animals, neurons preferring near disparities of single surfaces (near neurons) showed a near bias for overlapping stimuli, while neurons preferring far disparities (far neurons) showed a far bias. In the third animal, both near and far neurons displayed a near bias, though the near neurons showed a stronger near bias. All three animals exhibited an initial near bias across neurons relative to the average of the responses to the individual surfaces. Although attention modulated neuronal responses, the disparity bias was not caused by attention. We also found that the effect of attention was consistent with object-based, rather than feature-based attention. We proposed a model in which the pool size of the neuron population that weighs the responses to individual stimulus components can be variable. This model is a novel extension of the standard normalization model and provides a unified explanation for the disparity bias across animals. Our results reveal how MT neurons encode multiple stimuli moving at different depths and present new evidence of response modulation by object-based attention. The disparity bias allows subgroups of neurons to preferentially represent individual surfaces of multiple stimuli at different depths, thereby facilitating segmentation.