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Biomedical subjects

Wei Yang

Publications and source records attributed to Wei Yang.

At least 19 recordsLinked to original sources

The global prevalence of horizontal strabismus: A systematic review and meta-analysis with a focus on ethnic variation.

The prevalence of the 2 types of horizontal strabismus, esotropia and exotropia, varies considerably between studies. This variability has been attributed to factors such as geography/environment, research methodology, age of study subjects, and/or ethnicity. Comprehensive estimates of regional and global prevalences of esotropia and exotropia are lacking, making it difficult to recognize true patterns, trends, and etiologies. We compile prevalences and ratios of esotropia to exotropia from 315 population-based studies and 374 clinic-based studies. We analyze data to assess effects of ethnicity, geography, age, and we identify generational changes of horizontal strabismus. Major ethnicities differ in patterns and ratios of esotropia and exotropia prevalence, not only in Caucasians and East Asians, but also Latinos/Hispanics, South Asians, Africans, and Native Americans. Compared to population-based studies, clinic-based studies underestimate exotropia frequency. By weighing prevalences according to the population size of ethnicities, we estimate the worldwide prevalence of horizontal strabismus in the current generation at 1.81% (138.5 million people), comprising 60.0 million people with esotropia (0.67%) and 87.5 million with exotropia (1.14%). In the previous generation, the worldwide prevalence of horizontal strabismus was 1.64% (86.5 million people), comprising 50.5 million with esotropia (0.96%) and 36.0 million with exotropia (0.68%). Esotropia and exotropia prevalences differ between generations within the same ethnicity, indicating that extrinsic factors can modify the underlying intrinsic (genetic) disposition.

Humans↗

Biocontrol potential and molecular basis of predation in a marine raptorial ciliate.

Predator-prey interactions are widespread across organisms and are key drivers of morphological and behavioral evolution. Despite this, predation remains poorly understood among microbial eukaryotes, mostly due to the absence of a tractable experimental system that allows quantitative, reproducible investigation. This study establishes the marine raptorial ciliate Chaenea vorax as a highly efficient predator, with Rosenzweig-MacArthur model simulations based on predation data showing that only a few dozen individuals can eliminate the vast majority of the facultatively pathogenic ciliate Uronema marinum within 1-2 days, providing a quantitative basis for developing predator-based biocontrol strategies in aquaculture. Genomic analysis shows that C. vorax possesses a highly fragmented macronuclear genome enriched with predation-related pathways, including calcium-mediated contractility, cellular proteolysis, toxin expulsion systems, among others. Transcriptomic profiling during predation events further demonstrates significant upregulation of genes involved in cytoskeletal remodeling, proteolytic activity, and cellular detoxification. Evolutionary analyses suggest that C. vorax has an extremely long evolutionary history, exceptionally high nucleotide diversity even among ciliates, and gene family expansions linked to predatory adaptation. Although the prey possesses certain defensive mechanisms (e.g. trichocysts), these are largely ineffective against short-term predation in closed aquatic environments. These findings provide fundamental insights into the molecular basis of predation in ciliates and suggest the potential utility of C. vorax in biocontrol applications targeting pathogenic ciliates.

Ciliophora↗

Dual-patterned pluripotent stem cells self-organize into a human embryo model with extended anterior-posterior patterning.

Human gastruloids are a powerful class of stem cell-derived models that recapitulate key features of early embryonic development, including symmetry breaking and the emergence of three germ layers1-3. However, they lack anterior embryonic structures and coordinated axial organization4-6. To address this limitation, we pre-patterned human pluripotent stem cells (hPSCs) by exposing them to either anterior (FGF2) or posterior (CHIR99021 [CHIR] & retinoic acid [RA]) cues. Upon mixing, these dual-patterned hPSCs interacted and self-organized into elongated structures with both anterior and posterior features-which we term anterior-posterior (AP) human gastruloids. Anteriorly pre-treated cells robustly intercalated into posteriorly pre-treated cells, collectively giving rise to a continuum of neural tissues-including a brain-like domain, a neural tube-like structure, and neuro-mesodermal progenitors (NMPs)-with segmented somites arrayed bilaterally. Single cell RNA sequencing (scRNA-seq) revealed that human AP gastruloids contain cell types resembling the midbrain-hindbrain boundary (MHB), regionalized hindbrain structures (i .e. rhombomeres 1-8), regionalized neural crest (i.e. cranial, vagal, trunk)7,8 and head mesoderm. Transcriptomic comparisons to primate embryos revealed that human AP gastruloids most closely resemble Carnegie stage 11 (CS11) embryos. While they lack a notochord and full dorsal-ventral polarity, human AP gastruloids recapitulate key spatial and temporal features of early neurulation and somitogenesis. Perturbation of folic acid metabolism or rho-associated kinase (ROCK) signaling induced spinal cord defects, phenocopying aspects of spina bifida and other neural tube defects, highlighting this model's potential for studying congenital disorders9. AP gastruloids may serve as a simple, robust, scalable platform for modeling coordinated human AP body axis development. More broadly, our results suggest that controlled interactions between differentially prepatterned progenitors can initiate self-organization of complex body axis features. The "pattern-and-mix" strategy may serve as a generalizable framework for assembling spatially organized stem cell models of mammalian development.

Journal Article↗

BCLAF1 restrains stress responses in hematopoietic stem cells to support expansion and repopulation.

Hematopoietic stem cells (HSCs) rapidly expand during fetal development and after stress. Here, we identify B-cell lymphoma-2-associated factor 1 (BCLAF1) as a regulator of HSC repopulation activity, with roles in the expansion of fetal HSCs and hematopoietic reconstitution after stem cell transplantation. Using mice with hematopoietic-specific and inducible deletion of Bclaf1, we find that BCLAF1 promotes fetal HSC development but is dispensable for the maintenance of adult HSCs at steady state. Loss of BCLAF1 in either fetal or adult HSCs significantly impairs their self-renewal and multilineage reconstitution activity after stem cell transplantation. Single-cell RNA sequencing of fetal hematopoietic progenitors reveals that loss of BCLAF1 reduces long-term HSCs and restrains the expression of stress response genes. BCLAF1 associates with chromatin throughout the genome of fetal and adult hematopoietic cells, likely through indirect mechanisms, to regulate transcriptional programs. These results establish a novel function for the transcriptional regulator BCLAF1 in limiting stress responses in HSCs, thereby preserving HSC development during embryogenesis and repopulation function after stem cell transplant.

Hematopoietic Stem Cells↗

Diagnosis with Metagenomic Next-Generation Sequencing (mNGS) technology and real-time PCR for SARS-CoV-2 Omicron detection using various nasopharyngeal swabs in SARS-CoV-2 Omicron.

BACKGROUND: The SARS-CoV-2 Omicron variant, with the main subtypes BA.5.2 and BF.7 in China, led to off-target effects on the S and N genes from December 1, 2022, to January 31, 2023. The kits used for studying and developing these agents were not adequately and independently evaluated. It is important to verify the performance of commercial Real-Time quantitative PCR (RT-qPCR) tests. OBJECTIVE: We conducted a clinical evaluation of two Real Time SARS-CoV-2 Omicron assays to verify their performance using various detection reagents and clinical specimens. METHODS: We performed clinical evaluations of two existing Chinese SARS-CoV-2 Omicron RT-qPCR kits 2019-nCoV nucleic acid diagnostic kits (Fosun Biotechnology, National instrument registration 20203400299, Shanghai, China) and COVID-19 nucleic acid detection kits (eDiagnosis Biomedicine, National instrument registration 20203400212, Wuhan, China) and using BSD (Bondson) (Guangzhou Bondson Biotechnology Co. Ltd, batch number 2022101), quality controls provided by the inspection center and a large number of clinically confirmed specimens. RESULTS: The concordance rates for the Fosun and eDiagnosis kits were 95% and 100%, respectively. The detection limit for the Fosun and eDiagnosis kits was verified to be 300 copies/mL and 500 copies/mL. The Fosun assay exhibited the largest coefficient of variation (CV) for ORF1ab and N gene at the detection limit concentration (4.80%, 3.49%), whereas eDiagnosis showed a smaller CV (0.93%, 1.10%). In the reference product from the Hangzhou Clinical Laboratory Center test, it was found that Fosun had the lowest sensitivity of 93.47% and a specificity of 100%, while eDiagnosis exhibited 100% for both sensitivity and specificity. The lowest single target gene detection rate of Fosun reagents was 68.7% for the ORF1ab gene and 87.5% for the N gene, while eDiagnosis detection rate was 100%. Among the clinical group S specimens, the missed detection rate of the Fosun reagent was 10.9%, which was higher than the 3.9% of eDiagnosis. However, there was no significant difference in the clinical diagnostic efficiency of the two reagents. CONCLUSIONS: The ORF1ab and N assays of SARS-CoV-2 Omicron on the eDiagnosis platform yielded higher values compared to those on the Fosun platform. Consequently, the eDiagnosis kit has also been used as standard detection reagents. Considering that the Fosun reagent has a relatively low detection limit and targets three single genes, it is more advantageous as a confirmatory reagent for the new museum.

Humans↗

A quantum mechanics/molecular mechanics study of the reaction mechanism of the hepatitis C virus NS3 protease with the NS5A/5B substrate.

Combined quantum mechanics and molecular mechanics (QM/MM) calculations were carried out to characterize the reaction mechanism of the NS3 protease with its preferred substrate (NS5A/5B). The main purpose of this study was to locate the barrier states and intermediates along the distinguished coordinate path (DCP) involved in this process. These structures, and in particular the one corresponding to the first barrier state and intermediate (B1 and I1), could be a starting point for the synthesis of inhibitors of this protease, which could be used to treat hepatitis C. The two first steps of the reaction mechanism were studied, i.e., the acylation step and the breaking of the peptide bond. The first step takes place through a tetracoordinated intermediate, as suggested from previous works on other Serine proteases. The importance of the different amino acid residues was also considered (perturbation study where the MM charges of each residue were set to zero independently). The residues of the oxyanion hole were confirmed as the most important for the electrostatic stabilization of the tetracoordinate intermediate. Moreover, the role of other residues, e.g., Arg-155 and Asp-79, was also explained.

Acylation↗

Simulated scaling method for localized enhanced sampling and simultaneous "alchemical" free energy simulations: a general method for molecular mechanical, quantum mechanical, and quantum mechanical/molecular mechanical simulations.

A potential scaling version of simulated tempering is presented to efficiently sample configuration space in a localized region. The present "simulated scaling" method is developed with a Wang-Landau type of updating scheme in order to quickly flatten the distributions in the scaling parameter lambdam space. This proposal is meaningful for a broad range of biophysical problems, in which localized sampling is required. Besides its superior capability and robustness in localized conformational sampling, this simulated scaling method can also naturally lead to efficient "alchemical" free energy predictions when dual-topology alchemical hybrid potential is applied; thereby simultaneously, both of the chemically and conformationally distinct portions of two end point chemical states can be efficiently sampled. As demonstrated in this work, the present method is also feasible for the quantum mechanical and quantum mechanical/molecular mechanical simulations.

Algorithms↗

Hot-melt extrusion for enhanced delivery of drug particles.

With the recent advent of nanotechnology for pharmaceutical applications, drug particle engineering is the focus of increasing interest as a viable approach for overcoming solubility limitations of poorly water-soluble drugs. Although these particle engineering techniques have been proven successful for enhancing the dissolution properties of many poorly water-soluble drugs, there are limitations associated with them such as particle aggregation, morphological instability, and poor wettability. The aim of this study was to demonstrate a processing technique in which hot-melt extrusion (HME) is utilized to overcome these limitations. Micronized particles of amorphous itraconazole (ITZ) stabilized with PVP or HPMC were produced and subsequently melt extruded with poloxamer 407 and PEO 200 M to deaggregate and disperse the particles into the hydrophilic polymer matrix. Differential scanning calorimetry, X-ray diffraction, and scanning electron microscopy were used to demonstrate that the HME process did not alter the properties of the micronized particles. Dissolution testing conducted at sink conditions revealed that the dissolution rate of the micronized particles was improved by HME due to particle deaggregation and enhanced wetting. Supersaturation dissolution testing demonstrated that the ITZ-HPMC micronized particle extrudates provided superior supersaturation of ITZ compared to the ITZ-PVP micronized particle extrudates. Supersaturation dissolution testing incorporating a pH change (from pH 1.2 to 6.8 at 2 h) revealed that neither micronized particle extrudate formulation significantly reduced the rate of ITZ precipitation from supersaturated solution once pH was increased. Moreover, the two extrudate formulations performed very similarly when only considering dissolution testing from just before pH adjustment through the duration of testing at neutral pH. From oral dosing of rats, it was determined that the two extrudate formulations performed similarly in vivo as confirmed by their statistically equivalent AUC values. By correlating the results of supersaturation dissolution testing with pH change to the in vivo AUC, it appears that rapid precipitation of ITZ occurs upon entrance into the more neutral pH environment of the small intestine resulting in a brief opportunity for absorption. This suggests that perhaps the optimum formulation approach for ITZ is to control drug release so as to retard precipitation as pH is increased and extend the absorption window in the small intestine.

Animals↗

UvrD helicase unwinds DNA one base pair at a time by a two-part power stroke.

Helicases use the energy derived from nucleoside triphosphate hydrolysis to unwind double helices in essentially every metabolic pathway involving nucleic acids. Earlier crystal structures have suggested that DNA helicases translocate along a single-stranded DNA in an inchworm fashion. We report here a series of crystal structures of the UvrD helicase complexed with DNA and ATP hydrolysis intermediates. These structures reveal that ATP binding alone leads to unwinding of 1 base pair by directional rotation and translation of the DNA duplex, and ADP and Pi release leads to translocation of the developing single strand. Thus DNA unwinding is achieved by a two-part power stroke in a combined wrench-and-inchworm mechanism. The rotational angle and translational distance of DNA define the unwinding step to be 1 base pair per ATP hydrolyzed. Finally, a gateway for ssDNA translocation and an alternative strand-displacement mode may explain the varying step sizes reported previously.

Adenosine Triphosphate↗

New differentiation pathway for double-negative regulatory T cells that regulates the magnitude of immune responses.

Recent studies have demonstrated that in peripheral lymphoid tissues of normal mice and healthy humans, 1% to 5% of alphabeta T-cell receptor-positive (TCR(+)) T cells are CD4(-)CD8(-) (double-negative [DN]) T cells, capable of down-regulating immune responses. However, the origin and developmental pathway of DN T cells is still not clear. In this study, by monitoring CD4 expression during T-cell proliferation and differentiation, we identified a new differentiation pathway for the conversion of CD4(+) T cells to DN regulatory T cells. We showed that the converted DN T cells retained a stable phenotype after restimulation and that furthermore, the disappearance of cell-surface CD4 molecules on converted DN T cells was a result of CD4 gene silencing. The converted DN T cells were resistant to activation-induced cell death (AICD) and expressed a unique set of cell-surface markers and gene profiles. These cells were highly potent in suppressing alloimmune responses both in vitro and in vivo in an antigen-specific manner. Perforin was highly expressed by the converted DN regulatory T cells and played a role in DN T-cell-mediated suppression. Our findings thus identify a new differentiation pathway for DN regulatory T cells and uncover a new intrinsic homeostatic mechanism that regulates the magnitude of immune responses. This pathway provides a novel, cell-based, therapeutic approach for preventing allograft rejection.

Animals↗

CHKA and PCYT1A gene polymorphisms, choline intake and spina bifida risk in a California population.

BACKGROUND: Neural tube defects (NTDs) are among the most common of all human congenital defects. Over the last two decades, accumulating evidence has made it clear that periconceptional intake of folic acid can significantly reduce the risk of NTD affected pregnancies. This beneficial effect may be related to the ability of folates to donate methyl groups for critical physiological reactions. Choline is an essential nutrient and it is also a methyl donor critical for the maintenance of cell membrane integrity and methyl metabolism. Perturbations in choline metabolism in vitro have been shown to induce NTDs in mouse embryos. METHODS: This study investigated whether single nucleotide polymorphisms (SNPs) in human choline kinase A (CHKA) gene and CTP:phosphocholine cytidylytransferase (PCYT1A) gene were risk factors for spina bifida. Fluorescence-based allelic discrimination analysis was performed for the two CHKA intronic SNPs hCV1562388 (rs7928739) and hCV1562393, and PCYT1A SNP rs939883 and rs3772109. The study population consisted of 103 infants with spina bifida and 338 non-malformed control infants who were born in selected California counties in the period 1989-1991. RESULTS: The CHKA SNP hCV1562388 genotypes with at least one C allele were associated with a reduced risk of spina bifida (odds ratio = 0.60, 95%CI = 0.38-0.94). The PCYT1A SNP rs939883 genotype AA was associated with a twofold increased risk of spina bifida (odds ratio = 1.89, 95% CI = 0.97-3.67). These gene-only effects were not substantially modified by analytic consideration to maternal periconceptional choline intake. CONCLUSION: Our analyses showed genotype effects of CHKA and PCYT1A genes on spina bifida risk, but did not show evidence of gene-nutrient interactions. The underlying mechanisms are yet to be resolved.

California↗

Differential expression profiling between the relative normal and dystrophic muscle tissues from the same LGMD patient.

BACKGROUND: Limb-girdle muscular dystrophy (LGMD) is a group of heterogeneous muscular disorders with autosomal dominant and recessive inheritance, in which the pelvic or shoulder girdle musculature is predominantly or primarily involved. Although analysis of the defective proteins has shed some light onto their functions implicated in the etiology of LGMD, our understanding of the molecular mechanisms underlying muscular dystrophy remains incomplete. METHODS: To give insight into the molecular mechanisms of AR-LGMD, we have examined the differentially expressed gene profiling between the relative normal and pathological skeletal muscles from the same AR-LGMD patient with the differential display RT-PCR approach. The research subjects came from a Chinese AR-LGMD family with three affected sisters. RESULTS: In this report, we have identified 31 known genes and 12 unknown ESTs, which were differentially expressed between the relative normal and dystrophic muscle from the same LGMD patient. The expression of many genes encoding structural proteins of skeletal muscle fibers (such as titin, myosin heavy and light chains, and nebulin) were dramatically down-regulated in dystrophic muscles compared to the relative normal muscles. The genes, reticulocalbin 1, kinectin 1, fatty acid desaturase 1, insulin-like growth factor binding protein 5 (IGFBP5), Nedd4 family interacting protein 1 (NDFIP1), SMARCA2 (SWI/SNF related, matrix associated, actin dependent regulator of chromatin, subfamily a, member 2), encoding the proteins involved in signal transduction and gene expression regulation were up-regulated in the dystrophic muscles. CONCLUSION: The functional analysis of these expression-altered genes in the pathogenesis of LGMD could provide additional information for understanding possible molecular mechanisms of LGMD development.

Journal Article↗

Human MutLalpha: the jack of all trades in MMR is also an endonuclease.

Recently, Paul Modrich's group reported the discovery of an intrinsic endonuclease activity for human MutLalpha. This breakthrough provides a satisfactory answer to the longstanding puzzle of a missing nuclease activity in human mismatch repair and will undoubtedly lead to new investigations of DNA repair and replication. Here, the implications of this exciting new finding are discussed in the context of mismatch repair in Escherichia coli and humans.

Adenosine Triphosphatases↗

Myostatin induces cyclin D1 degradation to cause cell cycle arrest through a phosphatidylinositol 3-kinase/AKT/GSK-3 beta pathway and is antagonized by insulin-like growth factor 1.

Myostatin is a transforming growth factor beta superfamily member and is known as an inhibitor of skeletal muscle cell proliferation and differentiation. Exposure to myostatin induces G1 phase cell cycle arrest. In this study, we demonstrated that myostatin down-regulates Cdk4 activity via promotion of cyclin D1 degradation. Overexpression of cyclin D1 significantly blocked myostatin-induced proliferation inhibition. We further showed that phosphorylation at threonine 286 by GSK-3beta was required for myostatin-stimulated cyclin D1 nuclear export and degradation. This process is dependent upon the activin receptor IIB and the phosphatidylinositol 3-kinase/Akt pathway but not Smad3. Insulin-like growth factor 1 (IGF-1) treatment or Akt activation attenuated the myostatin-stimulated cyclin D1 degradation as well as the associated cell proliferation repression. In contrast, attenuation of IGF-1 signaling caused C2C12 cells to undergo apoptosis in response to myostatin treatment. The observation that IGF-1 treatment increases myostatin expression through a phosphatidylinositol 3-kinase pathway suggests a possible feedback regulation between IGF-1 and myostatin. These findings uncover a novel role for myostatin in the regulation of cell growth and cell death in concert with IGF-1.

Animals↗

Quality of life after radiofrequency ablation combined with transcatheter arterial chemoembolization for hepatocellular carcinoma: comparison with transcatheter arterial chemoembolization alone.

OBJECTIVE: Comprehensive studies are scarce with regard to the quality of life (QOL) of hepatocellular carcinoma (HCC) patients after transcatheter arterial chemoembolization (TACE) and/or radiofrequency ablation (RFA) treatment. The purpose of this study was to examine the impact of TACE alone and that of the TACE followed by RFA (TACE-RFA) on QOL in HCC patients. METHODS: QOL was measured using the Functional Assessment of Cancer Therapy-General (FACT-G) (Version 4.0) questionnaire, translated into Chinese, as a measure of QOL among Chinese HCC patients. Prospectively, 83 patients in both TACE group (n = 40) and TACE-RFA group (n = 43) completed the questionnaire at baseline and 3 months after treatment, respectively. RESULTS: The TACE-RFA group resulted in a significantly higher total QOL score, socio-family well-being score, and functional well-being score than that of TACE group, 3 months after respective treatment. Liver function, tumor recurrence and complication, age, income were the most important factors affecting the QOL of HCC patients after treatment. The logistic regression analyses showed that Child-Pugh Class and tumor recurrence after treatment were independent predictors of post-treatment QOL scores of HCC patients. CONCLUSIONS: The overall QOL of HCC patients in TACE-RFA group was maintained at a relatively higher level than that of TACE group. TACE followed by RFA appeared to be more favorable than TACE alone with respect to QOL.

Aged↗

Risks of human limb deficiency anomalies associated with 29 SNPs of genes involved in homocysteine metabolism, coagulation, cell-cell interactions, inflammatory response, and blood pressure regulation.

This study explored risks of limb deficiency anomalies associated with 29 single nucleotide polymorphisms (SNPs) of genes involved in homocysteine metabolism, coagulation, cell-cell interaction, inflammatory response, and blood pressure regulation. The authors genotyped 96 cases and 437 non-malformed controls from a California population-based case-control study (1987-1988 birth cohort). Increased risk of limb anomaly was observed for three SNPs: heterozygosity for F5 Arg506Gln, with an odds ratio (OR) of 2.5 (95% confidence interval (CI), 1.0, 6.5); heterozygosity for TNF (-376)G > A, OR 2.1 (0.7, 6.2); and homozygosity for NPPA 2238T > C, OR 4.0 (1.1, 15.4). We hypothesized that effects of variant genotypes in the presence of maternal smoking, and/or in the absence of supplement intake, may exceed effects of any of these factors alone. In particular, findings for polymorphisms in SERPINE1, ITGA2, SELE, TNF, LTA, NPPA, GNB3, and ADRB2 supported the hypotheses, both for smoking and for supplement intake. These results suggest involvement of genetic variation of biologically relevant candidate genes, and gene-environment interaction, for some limb anomalies whose pathogenesis may be related to altered vascular tone or integrity.

Blood Coagulation↗

Prediction of EF-hand calcium-binding proteins and analysis of bacterial EF-hand proteins.

The EF-hand protein with a helix-loop-helix Ca(2+) binding motif constitutes one of the largest protein families and is involved in numerous biological processes. To facilitate the understanding of the role of Ca(2+) in biological systems using genomic information, we report, herein, our improvement on the pattern search method for the identification of EF-hand and EF-like Ca(2+)-binding proteins. The canonical EF-hand patterns are modified to cater to different flanking structural elements. In addition, on the basis of the conserved sequence of both the N- and C-terminal EF-hands within S100 and S100-like proteins, a new signature profile has been established to allow for the identification of pseudo EF-hand and S100 proteins from genomic information. The new patterns have a positive predictive value of 99% and a sensitivity of 96% for pseudo EF-hands. Furthermore, using the developed patterns, we have identified zero pseudo EF-hand motif and 467 canonical EF-hand Ca(2+) binding motifs with diverse cellular functions in the bacteria genome. The prediction results imply that pseudo EF-hand motifs are phylogenetically younger than canonical EF-hand motifs. Our prediction of Ca(2+) binding motifs provides not only an insight into the role of Ca(2+) and Ca(2+)-binding proteins in bacterial systems, but also a way to explore and define the role of Ca(2+) in other biological systems (calciomics).

Amino Acid Motifs↗

Finite reservoir replica exchange to enhance canonical sampling in rugged energy surfaces.

A "finite reservoir" replica exchange method is presented to further enhance sampling upon the regular replica exchange method (REM) in a rugged energy surface. The present method can facilitate important sampling more efficiently by exchanging structures with configurations randomly selected from a finite-sized reservoir; this finite reservoir is pregenerated and updated by a mechanism of replica exchange with neighboring "temperature" simulations. In practice, this proposal revises exchange schedule in REM simulations in order to make productive exchange for conformational "tunneling" more frequent.

Journal Article↗