Publications by authors named "Yifei Wu"

62 Publications

MALDI-TOF-MS analysis of hydrolysis products of beechwood and birchwood xylans catalyzed by xylanase from Bacillus subtilis.

J Food Biochem 2021 Jun 29:e13841. Epub 2021 Jun 29.

College of Food Science and Technology, Northwest University, Xi'an, China.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was used to analyze the polymerization distribution of xylo-oligosaccharides from birchwood and beechwood xylans following hydrolysis by the xylanase (XynA) from Bacillus subtilis, which was obtained by recombinant expression and purified by Ni affinity column chromatography. The hydrolysis products of birchwood and beechwood xylans were analyzed by thin layer chromatography (TLC) and MALDI-TOF-MS. In the birchwood hydrolysate, the main neutral xylo-oligosaccharides were xylobiose (X ) and xylotriose (X ), and the acidic xylo-oligosaccharides (polymerization degree 4-12) were attached via a single methyl-glucuronic acid sidechain (MeG). Both X and X were identified in the beechwood xylan hydrolysate and acidic xylo-oligosaccharides (polymerization degree 4-16), which were structurally similar to those in the birchwood xylan hydrolysate. Therefore, the recombinant xylanase, XynA, has the potential to produce xylobiose (X ) and xylotriose (X ) as well as acidic xylo-oligosaccharides (MeGX ) that would be applied in food industry. PRACTICAL APPLICATIONS: Xylo-oligosaccharides are a novel functional food additive, which has great potential in improving the quality of food. Xylo-oligosaccharides with methyl-glucuronic acid sidechains (MeG) are acidic xylo-oligosaccharides (MeGXn), which can be applied in the preparation of drugs for the treatment of cystitis and mucopolysaccharidosis. In this study, xylanase XynA was first obtained by gene cloning and expression and then used to hydrolyze the birchwood and beechwood xylans. The polymerization distribution of xylo-oligosaccharides generated during the enzymatic digestion was then determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Through enzyme hydrolysis, we are able to produce xylobiose and xylotriose for food additives.
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http://dx.doi.org/10.1111/jfbc.13841DOI Listing
June 2021

Incidence Density and Predictors of Multidrug-Resistant Tuberculosis Among Individuals With Previous Tuberculosis History: A 15-Year Retrospective Cohort Study.

Front Public Health 2021 28;9:644347. Epub 2021 May 28.

Hangzhou Center for Disease Control and Prevention, Hangzhou, China.

To date, too little attention has been paid to monitoring and estimating the risk of incident multidrug-resistant tuberculosis (MDR-TB) among individuals with a previous tuberculosis history (PTBH). The purpose of this study was to assess the incidence of and risk factors for MDR-TB in those individuals. Between 2005 and 2020, a large, retrospective, population-based cohort study was performed in Hangzhou, China. A multivariable Cox regression model was used to evaluate independent predictors of incident MDR-TB among individuals with PTBH. The incidence density of MDR-TB was 22.6 per 1,000 person-years (95% confidence level and an interval of 20.9-24.3) for individuals with PTBH. The incidence of MDR-TB increased significantly in individuals who • were under 60 years old. • were male. • had a history of direct contact. • came from low-income families. • worked in high-risk occupations. • lived in rural areas. • had a retreatment TB history. • had an unfavorable outcome in their previous treatment ( < 0.05). In addition, we found that the following factors were significantly linked to the MDR-TB risk among individuals with PTBH ( < 0.05): • sociodemographic factors such as the 21-30 and 31-40 year age groups, or a history of direct contact. • clinical factors like passive modes of TB case finding (PMTCF), human immunodeficiency virus infection, unfavorable treatment outcomes, retreated TB history, non-standardized treatment regimens of retreatment TB patients, and duration of pulmonary cavities (DPC). • microbiological factors, such as duration of positive sputum culture. We also found that the 21-30 year age group, low family income, and PMTCF were significantly linked to incident MDR-TB only in males with PTBH, whilst the 41-50 year age group, extended treatment course, and DPC were significantly associated with female MDR-TB only. The incidence of MDR-TB was high, with a higher rate among subjects with a history of direct contact and unfavorable treatment outcomes. There was a gender difference in the incidence density and risk factors of MDR-TB among individuals with PTBH. Long-term monitoring and gender-specific risk-factor modifications should be given to individuals with PTBH.
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http://dx.doi.org/10.3389/fpubh.2021.644347DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8193499PMC
June 2021

Identification of TYR, TYRP1, DCT and LARP7 as related biomarkers and immune infiltration characteristics of vitiligo via comprehensive strategies.

Bioengineered 2021 12;12(1):2214-2227

Department of Dermatology, the First People's Hospital of Yunnan Province, The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China.

This study aims to explore biomarkers associated with vitiligo and analyze the pathological role of immune cell infiltration in the disease. We used the robust rank aggregation (RRA) method to integrate three vitiligo data sets downloaded from gene expression omnibus database, identify the differentially expressed genes (DEGs) and analyze the functional correlation. Then, the comprehensive strategy of combined weighted gene coexpression network analysis (WGCNA) and logical regression of the selection operator (LASSO), support vector machine recursive feature elimination (SVM-RFE), and random forest (RF) machine learning algorithm are employed to screen and biomarkers associated with vitiligo. Finally, the immune cell infiltration of vitiligo was evaluated by CIBERSORT, and the correlation between biomarkers and infiltrating immune cells was analyzed. Herein, we identified 131 robust DEGs, and enrichment analysis results showed that robust DEGs and melanogenesis were closely associated with vitiligo development and progression. TYR, TYRP1, DCT and LARP7 were identified as vitiligo-related biomarkers. Immune infiltration analysis demonstrated that CD4 T Cell, CD8 T Cell, Tregs, NK cells, dendritic cells, and macrophages were involved in vitiligo's pathogenesis. In summary, we adopted a comprehensive strategy to screen biomarkers related to vitiligo and explore the critical role of immune cell infiltration in vitiligo.: TYR, Tyrosinase; TYRP1, Tyrosinase-related protein-1; DCT, dopachrome tautomerase; LARP7, La ribonucleoprotein domain family, member-7; RRA, robust rank aggregation; DEGs, differentially expressed genes; WGCNA, weighted gene coexpression network analysis; LASSO, logical regression of the selection operator; SVM-RFE, support vector machine recursive feature elimination; RF, random forest; GWAS, Genome-wide association study; FasL, Fas-Fas ligand; Tregs, T-regulatory cells; NK, natural killer; GEPCs, gene expression profiling chips; GO, gene ontology; GSEA, gene set enrichment analysis; FDR, false discovery rate; AUC, area under the curve; ROC, receiver-operating characteristic; BP, biological process; CC, cellular component; MF, molecular function.
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http://dx.doi.org/10.1080/21655979.2021.1933743DOI Listing
December 2021

Mutations in RNA Methyltransferase Gene Confer High Risk of Outflow Tract Malformation.

Front Cell Dev Biol 2021 21;9:623394. Epub 2021 Apr 21.

State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.

, encoding a cytosine-5 RNA methyltransferase and located in the 7q11.23 locus, is a candidate gene for tetralogy of Fallot (TOF). Deletion of the 7q11.23 locus in humans is linked to cardiac outflow tract (OFT) disorders including TOF. We identified four potential pathogenic mutations in the coding region of and which were enriched in TOF patients by an association study of 132 TOF patients and 2,000 in-house controls ( = 1.44 × 10). We then generated a null ( ) mouse model to validate the human findings by defining the functions of in OFT morphogenesis. The OFT did not develop properly in the deletion embryonic heart. We found a misalignment of the aorta and septum defects caused by the delayed fusion of the membraneous ventricular spetum as an OFT development delay. This caused OFT development delay in 27 of 64 (42.2%) mice. Moreover, we also found OFT development delay in 8 of 51 (15.7%) mice. Further functional experiments showed that the loss of function impaired the 5-methylcytosine (mC) modification and translation efficiency of essential cardiac genes. is required for normal OFT morphogenesis and it regulates the mC modification of essential cardiac genes. Our findings suggest the involvement of in the pathogenesis of TOF.
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http://dx.doi.org/10.3389/fcell.2021.623394DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8097101PMC
April 2021

Genome-wide identification and expression analysis of the B-box transcription factor gene family in grapevine (Vitis vinifera L.).

BMC Genomics 2021 Mar 29;22(1):221. Epub 2021 Mar 29.

State Key Laboratory of Crop Stress Biology in Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shaanxi, China.

Background: B-box (BBX) zinc-finger transcription factors play important roles in plant growth, development, and stress response. Although these proteins have been studied in model plants such as Arabidopsis thaliana or Oryza sativa, little is known about the evolutionary history or expression patterns of BBX proteins in grapevine (Vitis vinifera L.).

Results: We identified a total of 25 VviBBX genes in the grapevine genome and named them according to the homology with Arabidopsis. These proteins were classified into five groups on the basis of their phylogenetic relationships, number of B-box domains, and presence or absence of a CCT domain or VP motif. BBX proteins within the same group showed similar exon-intron structures and were unevenly distributed in grapevine chromosomes. Synteny analyses suggested that only segmental duplication events contributed to the expansion of the VviBBX gene family in grapevine. The observed syntenic relationships between some BBX genes from grapevine and Arabidopsis suggest that they evolved from a common ancestor. Transcriptional analyses showed that the grapevine BBX genes were regulated distinctly in response to powdery mildew infection and various phytohormones. Moreover, the expression levels of a subset of BBX genes in ovules were much higher in seedless grapevine cultivars compared with seeded cultivars during ovule development, implying a potential role in seed abortion. Additionally, VviBBX8, VquBBX15a and VquBBX29b were all located in the nucleus and had transcriptional activity except for VquBBX29b.

Conclusions: The results of this study establish the genome-wide analysis of the grapevine BBX family and provide a framework for understanding the biological roles of BBX genes in grapevine.
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http://dx.doi.org/10.1186/s12864-021-07479-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8008696PMC
March 2021

Analyzing knowledge entities about COVID-19 using entitymetrics.

Scientometrics 2021 Mar 12:1-19. Epub 2021 Mar 12.

Department of Information Management, Peking University, Beijing, China.

COVID-19 cases have surpassed the 109 + million markers, with deaths tallying up to 2.4 million. Tens of thousands of papers regarding COVID-19 have been published along with countless bibliometric analyses done on COVID-19 literature. Despite this, none of the analyses have focused on domain entities occurring in scientific publications. However, analysis of these bio-entities and the relations among them, a strategy called entity metrics, could offer more insights into knowledge usage and diffusion in specific cases. Thus, this paper presents an entitymetric analysis on COVID-19 literature. We construct an entity-entity co-occurrence network and employ network indicators to analyze the extracted entities. We find that ACE-2 and C-reactive protein are two very important genes and that lopinavir and ritonavir are two very important chemicals, regardless of the results from either ranking.
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http://dx.doi.org/10.1007/s11192-021-03933-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7953944PMC
March 2021

Fate of antibiotic resistance genes and metal resistance genes during the thermophilic fermentation of solid and liquid swine manures in an ectopic fermentation system.

Ecotoxicol Environ Saf 2021 Apr 13;213:111981. Epub 2021 Feb 13.

Institute of Plant Protection and Microbiology, Zhejiang Academy of Agriculture Science, Hangzhou, Zhejiang, PR China.

Environmental pollution due to resistance genes from livestock manure has become a serious issue that needs to be resolved. However, little studies focused on the removal of resistance genes in simultaneous processing of livestock feces and urine. This study investigated the fate of antibiotic resistance genes (ARGs), metal resistance genes (MRGs), and class 1 integron-integrase gene (intI1) during thermophilic fermentation of swine manure in an ectopic fermentation system (EFS), which has been regarded as a novel system for efficiently treating both feces and urine. The abundances of MRGs and tetracycline resistance genes were 34.44-97.71% lower in the EFS. The supplementation of heavy metals significantly increased the abundance of intI1, with the enhancement effect of copper being more prominent than that of zinc. The highest abundances of resistance genes and intI1 were observed at high Cu levels (A2), indicating that Cu can increase the spreading of resistance genes through integrons. Network analysis revealed the co-occurrence of ARGs, MRGs, and intI1, and these genes potentially shared the same host bacteria. Redundancy analysis showed that the bacterial community explained most of the variations in ARGs, and environmental factors had influences on ARGs abundances by modulating the bacterial community composition. The decreased Sphingomonas, Comamonas, Acinetobacter, Lactobacillus, Bartonella, Rhizobium, and Bacteroides were mainly responsible for the reduced resistance genes. These results demonstrate that EFS can reduce resistance genes in simultaneous processing of livestock feces and urine.
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http://dx.doi.org/10.1016/j.ecoenv.2021.111981DOI Listing
April 2021

Impact of different tuberculosis history at the onset of future multidrug-resistant tuberculosis: A large, retrospective, population-based cohort study.

J Glob Antimicrob Resist 2021 03 24;24:158-168. Epub 2020 Dec 24.

Hangzhou Center for Disease Control and Prevention, Hangzhou 310021, China. Electronic address:

Objectives: The impact of tuberculosis (TB) history on the risk of multidrug-resistant tuberculosis (MDR-TB) is not yet fully understood. We aimed to identify the impact of different TB history at the onset of future MDR-TB.

Methods: A large, retrospective, population-based cohort study was performed between 2005 and 2019. A multivariable Cox model was used to evaluate independent risk factors for MDR-TB for individuals with different previous TB history (PTBH), such as newly diagnosed TB history (NDTH) and re-treated TB history (RTH).

Results: Overall, 12 172 individuals with PTBH were included in this study. The main impacts of different PTBH at the onset of future MDR-TB were as follows: (a) low family income, high-risk occupation, TB patients with severe infection, extended or shortened treatment course, 2H3R3Z3E3/4H3R3 and frequency of sputum culture were significantly linked to incident MDR-TB only in individuals with NDTH (P < 0.05); (b) passive mode of TB case finding, individualised treatment regimens, 3HRZES/6HRE, duration of pulmonary cavities, excellent frequency of chest X-ray examination and duration of negative sputum smear were significantly associated with incident MDR-TB only in individuals with RTH (P < 0.05); (c) age <60 years, history of direct contact, human immunodeficiency virus (HIV) infection, unsuccessful treatment and duration of positive sputum culture were related to incident MDR-TB in both categories of PTBH individuals (P < 0.05).

Conclusion: Early and differential surveillances, assessments and interventions for reducing the risk of MDR-TB among individuals with different PTBH play a key role.
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http://dx.doi.org/10.1016/j.jgar.2020.12.001DOI Listing
March 2021

Time to sputum culture conversion and its predictors among patients with multidrug-resistant tuberculosis in Hangzhou, China: A retrospective cohort study.

Medicine (Baltimore) 2020 Dec;99(50):e23649

SJTU-Yale Joint Center for Biostatistics and Data Science, Shanghai Jiao Tong University (SJTU), Shanghai, China.

The objective is to investigate the time to initial sputum culture conversion (SCC) and its predictors among multidrug-resistant tuberculosis (MDR-TB) patients in Hangzhou, China.A retrospective cohort study was conducted among patients who initiated MDR-TB treatment from 2011 to 2015 in Hangzhou, China. Successful achievement of initial SCC was defined as 2 consecutive negative cultures taken at least 30 days apart after initiation of treatment of MDR-TB. Successful treatment outcomes included being cured and completing treatment, while poor treatment outcomes included treatment failure, loss to follow-up, and death. Time to initial SCC was analyzed using the Kaplan-Meier method, and Cox proportional hazards regression was used to identify predictors of SCC.Among 384 patients enrolled with MDR-TB, 359 (93.5%) successfully achieved initial SCC after a median of 85 days (interquartile range, 40-112 days). A higher rate of SCC was observed in participants with successful treatment outcomes than those with poor treatment outcomes (P<.01). Multivariate analysis showed that age 25 to 64 years (compared with age<25; adjusted odds ratio [AOR], 0.7; 95% confidence interval [CI], 0.5-0.9; P < .01), age ≥65 years (compared with age < 25; AOR, 0.5; 95% CI, 0.3-0.8; P < .01), and household registration in Hangzhou (compared with non-Hangzhou registration; AOR, 1.3; 95% CI, 1.0-1.5; P < .05) were found to be associated with SCC.Although high SCC and treatment success rates were observed among MDR-TB patients in Hangzhou, the prolonged duration to initial SCC underscores the importance of emphasizing measures for infection control. A new policy of shifting outpatient treatment to inpatient treatment in China may reduce the risk of transmission from patients in the time window prior to SCC.
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http://dx.doi.org/10.1097/MD.0000000000023649DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738096PMC
December 2020

identification of drug candidates against COVID-19.

Inform Med Unlocked 2020 20;21:100461. Epub 2020 Oct 20.

Computational Drug Discovery Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, 30602, GA, USA.

The COVID-19 pandemic has caused unprecedented health and economic crisis throughout the world. However, there is no effective medication or therapeutic strategy for treatment of this disease currently. Here, to elucidate the inhibitory effects, we first tested binding affinities of 11 HIV-1 protease inhibitors or their pharmacoenhancers docked onto SARS-CoV-2 main protease (M ), and 12 nucleotide-analog inhibitors docked onto RNA dependent RNA polymerase (RdRp). To further obtain the effective drug candidates, we screened 728 approved drugs via virtual screening on SARS-CoV-2 M . Our results demonstrate that remdesivir shows the best binding energy on RdRp and saquinvir is the best inhibitor of M . Based on the binding energies, we also list 10 top-ranked approved drugs which can be potential inhibitors for M . Overall, our results do not only propose drug candidates for further experiments and clinical trials but also pave the way for future lead optimization and drug design.
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http://dx.doi.org/10.1016/j.imu.2020.100461DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7574721PMC
October 2020

Control of peptide hydrogel formation and stability via heating treatment.

J Colloid Interface Sci 2021 Feb 17;583:234-242. Epub 2020 Sep 17.

State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.

Heating treatment is widely used in the preparation of metallic materials with controlled phase behavior and mechanical properties. However, for the soft materials assembled by short peptides, especially simple dipeptides, the detailed influences of heating treatment on the structures and functions of the materials remain largely unexplored. Here we showed that by thermal annealing or quenching of aromatic peptide solutions under kinetic control, we are able to control the self-assembly of peptide into materials with distinct phase behavior and macroscopic properties. The thermal annealing of the heated peptide solutions will lead to the formation of large nanobelts or bundles in solution, and no gels will be formed. However, by quenching the heated peptide solution, a self-supporting hydrogel will be formed quickly. Structure analysis revealed that the peptides preferred to self-assembled into much thinner and flexible nanohelices during quenching treatment. Moreover, the stability of the gels further increased with the repeated heating and quenching cycling of the peptide solutions. The results demonstrated that the heat treatment can be used to control the structure and function of self-assembled materials in a way similar to that of the conventional metallic or alloy materials.
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http://dx.doi.org/10.1016/j.jcis.2020.09.032DOI Listing
February 2021

Elucidating the Inhibitory Effect of Resveratrol and Its Structural Analogs on Selected Nucleotide-Related Enzymes.

Biomolecules 2020 08 22;10(9). Epub 2020 Aug 22.

Computational Drug Discovery Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, GA 30602, USA.

Resveratrol, the most widely studied natural phytochemical, has been shown to interact with different target proteins. Previous studies show that resveratrol binds and inhibits DNA polymerases and some other enzymes; however, the binding and functioning mechanisms remain unknown. The elucidated knowledge of inhibitory mechanisms of resveratrol will assist us in new drug discovery. We utilized molecular docking and molecular dynamics (MD) simulation to reveal how resveratrol and structurally similar compounds bind to various nucleotide-dependent enzymes, specifically, DNA polymerases, HIV-1 reverse transcriptase, and ribonucleotide reductase. The results show that resveratrol and its analogs exert their inhibitory effects by competing with the substrate dNTPs in these enzymes and blocking elongation of chain polymerization. In addition, the results imply that resveratrol binds to a variety of other ATP-/NTP-binding proteins.
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http://dx.doi.org/10.3390/biom10091223DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7563984PMC
August 2020

Nomogram for individualized prediction of incident multidrug-resistant tuberculosis after completing pulmonary tuberculosis treatment.

Sci Rep 2020 08 13;10(1):13730. Epub 2020 Aug 13.

Division of Infectious Diseases, Hangzhou Center for Disease Control and Prevention, 568 Mingshi Road, Hangzhou, 310021, China.

The purposes of this study were to construct a comprehensive nomogram for providing a simple, precise and personalized prediction of incident multidrug-resistant tuberculosis (MDR-TB) after completing pulmonary tuberculosis treatment (CPTBT). A matched case-control study (1:2 ratios) was performed between 2005 and 2018. A multivariable Cox regression analysis was used to evaluate independent predictors of incident MDR-TB after the CPTBT. A comprehensive nomogram was developed based on the multivariable Cox model. Overall, 1, 836 participants were included in this study. We developed and validated a simple-to-use nomogram that predicted the individualized risk of incident MDR-TB by using 10 parameters after the CPTBT. The concordance index of this nomogram was 0.833 [95% confidence interval (CI) 0.807-0.859] and 0.871 (95% CI 0.773-0.969) for the training and validation sets, respectively, which indicated adequate discriminatory power. The calibration curves for the risk of incident MDR-TB showed an optimal agreement between nomogram prediction and actual observation in the training and validation sets, respectively. The high sensitivity and specificity of nomogram was indicated by using a receiver operating characteristic curve analysis. Through this clinic tool, TB control executives could more precisely monitor, estimate and intervene the risk of incident MDR-TB among individuals with CPTBT.
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http://dx.doi.org/10.1038/s41598-020-70748-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7426812PMC
August 2020

Treatment outcomes of multidrug-resistant tuberculosis in Hangzhou, China, 2011 to 2015.

Medicine (Baltimore) 2020 Jul;99(30):e21296

SJTU-Yale Joint Center for Biostatistics and Data Science, Shanghai Jiao Tong University, Shanghai, China.

Treatment of multidrug-resistant tuberculosis (MDR-TB) is challenging. More research is needed to understand treatment outcomes and associated factors.A retrospective cohort study was conducted to assess trends and predictors of treatment success among 398 MDR-TB and extensively drug resistant TB patients who started treatment in 2011 to 2015 in Hangzhou, China. Sociodemographic and clinical characteristic data were obtained from the national reporting database. Chi-square test for trend was used to evaluate changes in treatment success rates over the study years, and Cox regression analysis was used to identify predictors for poor treatment outcomes.The treatment success rate was 76% (301/398) for all participants, 77% (298/387) for MDR-TB cases and 27% (3/11) for extensively drug-resistant tuberculosis -TB cases. Treatment success increased significantly from 66% among patients who started treatment in 2011 to 85% in 2015 (P < .01). Of the 97 (24.4%) patients with unsuccessful treatment outcomes, 10 (2.5%) died, 64 (16.1%) failed treatment, and 23 (5.8%) were lost to follow-up. Patients who started treatment in 2013 to 2015 were less likely to have unsuccessful outcomes than those who started in 2011-2012 (adjusted odds ratio [AOR] 0.4, 95% confidence interval [CI] 0.3-0.6), patients ≥25 years were more likely to have unsuccessful outcomes than younger patients (AOR 1.6, 95% CI 1.3-2.1), and cases with kanamycin resistance was associated with three times the odds of having unsuccessful outcomes than kanamycin-susceptible cases (AOR 3.0, 95% CI 1.5-5.8).With proper case management of MDR-TB, patients can achieve a high treatment success rate. Hangzhou's program offers clinical evidence that can be used to inform MDR-TB programs elsewhere in China and abroad.
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http://dx.doi.org/10.1097/MD.0000000000021296DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7387009PMC
July 2020

Self-assembly of multifunctional hydrogels with polyoxometalates helical arrays using nematic peptide liquid crystal template.

J Colloid Interface Sci 2020 Oct 2;578:218-228. Epub 2020 Jun 2.

State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China.

In this work, we report a strategy to self-assemble multifunctional hydrogels composed of highly ordered polyoxometalates (POMs) helical arrays using a liquid crystalline tripeptide as the template. The cationic peptide can self-assemble into long-range ordered nanofilaments with a diameter of ~4.1 nm in aqueous media. Through the incorporation of various multivalent polyoxometalates (POMs), the POMs clusters can spontaneously organize into periodic nanowire arrays by the colloidal co-assembly with the as-prepared nematic peptide nanofilaments. This leads to the formation of hybrid gels with tunable mechanical strength by simply changing the charge number of the POMs. The HPWO (noted as PW) [email protected] hybrid hydrogels show excellent adsorption performance of dyes. Moreover, the long-range aligned PW clusters within the co-assembled fiber bundles exhibit great improvement in the efficiency of photodegradation of dyes, which shows 8.7 times higher than that of the pristine PW clusters in the homogeneous phase. The synergistic effect between the adsorption and catalytic process within the hybrid gels is considered to be responsible for its highly catalytic activity. This work highlights a general pathway upon the well-defined organization of the various components into hybrid materials with superior properties using simple peptide liquid crystals as templates.
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http://dx.doi.org/10.1016/j.jcis.2020.05.116DOI Listing
October 2020

Family-based whole-genome sequencing identifies compound heterozygous protein-coding and noncoding mutations in tetralogy of Fallot.

Gene 2020 May 9;741:144555. Epub 2020 Mar 9.

State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing 211166, China; Department of Epidemiology and Biostatistics, Center for Global Health, Nanjing Medical University, Nanjing 211166, China. Electronic address:

Tetralogy of Fallot (TOF) is one of most serious cyanotic congenital heart disease (CHD) and the prevalence is estimated to be 1 in 3000 live births worldwide. Though multiple studies have found genetic variants as risk factors for TOF, they could only explain a small fraction of the pathogenesis. Here, we performed whole genome sequencing (WGS) for 6 individuals derived from 2 families to evaluate pathogenic mutations located in both coding and noncoding regions. We characterized the annotated deleterious coding mutations and impaired noncoding mutations in regulatory elements by various data analysis. Additionally, functional assays were conducted to validate function regulatory elements and noncoding mutations. Interestingly, a compound heterozygous pattern with pathogenic coding and noncoding mutations was identified in probands. In proband 1, biallelic mutations (g.139409115A > T, encoding p.Asn685Ile; g.139444949C > A) in NOTCH1 exon and its regulatory element were detected. In vitro experiments revealed that the regulatory element acted as a silencer and the noncoding mutation decreased the expression of NOTCH1. In proband 2, we also found compound heterozygous mutations (g. 216235029C > T, encoding p.Val2281Met; g. 216525154A > C) which potentially regulated the function of FN1 gene. In summary, our study firstly reported an instance of newly identified noncoding mutation in regulatory element within the compound heterozygous pattern in TOF. The results provided a deeper understanding of TOF genetic architectures.
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http://dx.doi.org/10.1016/j.gene.2020.144555DOI Listing
May 2020

A Pilot Study of All-Computational Drug Design Protocol-From Structure Prediction to Interaction Analysis.

Front Chem 2020 12;8:81. Epub 2020 Feb 12.

Computational Drug Discovery Laboratory, School of Electrical and Computer Engineering, College of Engineering, University of Georgia, Athens, GA, United States.

Speeding up the drug discovery process is of great significance. To achieve that, high-efficiency methods should be exploited. The conventional wet-bench methods hardly meet the high-speed demand due to time-consuming experiments. Conversely, approaches are much more efficient for drug discovery and design. However, approaches usually serve as a supportive role in research processes. To fully exert the strength of computational methods, we propose a protocol which integrates various approaches, from protein structure prediction to ligand-protein interaction simulation. As a proof of concept, human SK2/calmodulin complex was used as a target for validation. First, we obtained a predicted structure of SK2/calmodulin and predicted binding sites which were consistent with the literature data. Then we investigated the ligand-protein interaction via virtual mutagenesis, flexible docking, and binding affinity calculation. As a result, the binding energies of mutants have similar trends compared with the EC values ( = 0.6 for NS309 in V481 mutants). The results indicate that our protocol can be applied to the drug design of structure unknown proteins. Our study also demonstrates that the integration of approaches is feasible and it facilitates the acceleration of new drug discovery.
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http://dx.doi.org/10.3389/fchem.2020.00081DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7028743PMC
February 2020

EGF released from human placental mesenchymal stem cells improves premature ovarian insufficiency via NRF2/HO-1 activation.

Aging (Albany NY) 2020 02 10;12(3):2992-3009. Epub 2020 Feb 10.

Center of Reproduction and Genetics, Affiliated Suzhou Hospital of Nanjing Medical University, Suzhou Municipal Hospital, Suzhou 215002, China.

Human placental mesenchymal stem cells (hPMSCs) have the ability to release cytokines and to differentiate into the three germ layers. To date, the relevance of hPMSCs for the treatment of premature ovarian insufficiency (POI) disease through the regulation of oxidative stress is still unclear. Therefore, to evaluate the therapeutic efficiency and investigate the mechanism of hPMSCs, we generated a mouse model of POI and collected human ovarian granule cells (hGCs) from patients with POI. hPMSCs displayed therapeutic effects on POI ovarian function, including recovered follicular numbers and increased expression of oocyte markers. Furthermore, secretion of the cytokine EGF (epidermal growth factor) was higher from hPMSCs than it was from other cells. FACS and Western blot analyses showed that EGF elevated the proliferation and reduced the apoptosis in hGCs. hPMSCs and EGF inhibited oxidative stress levels. Protein assays demonstrated that EGF suppressed oxidative stress by dose-dependently upregulating the expression of the NRF2/HO-1 pathway, and it inhibited the apoptosis by regulating the PTEN/PI3K/AKT pathway. These findings provide an experimental foundation for hPMSCs in improving ovarian function through the secretion of EGF. The mechanism of action of EGF is related to protection from oxidative stress by activation of the NRF2/HO-1.
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http://dx.doi.org/10.18632/aging.102794DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7041770PMC
February 2020

Genetic variants in HLA-DP/DQ contribute to risk of acute myeloid leukemia: A case-control study in Chinese.

Pathol Res Pract 2020 Mar 20;216(3):152829. Epub 2020 Jan 20.

Department of Epidemiology and Biostatistics, School of Public Health, Nanjing Medical University, Nanjing, China; Jiangsu Key Lab of Cancer Biomarkers, Prevention and Treatment, Collaborative Innovation Center for Cancer Medicine, Nanjing Medical University, Nanjing, China. Electronic address:

Human leukocyte antigens (HLA) are heterodimeric cell surface molecules that bind short peptides derived from non-self and self proteins. Accumulative evidence showed that specific alleles of HLA class II were associated with the susceptibility to malignant tumors including acute leukemia. In this study, we investigated the association between four single nucleotide polymorphisms (SNPs) at HLA-DP/DQ and acute myeloid leukemia (AML) risk. We genotyped four SNPs in HLA-DP (rs3077 G > A and rs9277535 G > A) and HLA-DQ (rs2856718 A > G and rs7453920 G > A) in a case-control study of 545 AML cases and 1034 cancer-free controls using Taqman allelic discrimination assay. The associations between these SNPs and AML risk were estimated by computing the odds ratios (ORs) and their 95% confidence intervals (CIs) from multivariate logistic regression analysis. We found significant associations of the variant alleles in HLA-DP (rs3077 and rs9277535) and HLA-DQ rs7453920 with increased AML risk (adjusted OR = 1.29, 95%CI = 1.10-1.51for rs3077 in additive model; adjusted OR = 1.29, 95%CI = 1.11-1.51 for rs9277535 in additive model; adjusted OR = 3.18, 95%CI = 1.86-5.46 for rs7453920 in recessive model). When combining the effects of rs3077, rs9277535 and rs7453920, we found that AML risk was significantly increased with the increasing number of variant alleles of the three SNPs in a dose-dependent manner (P for trend < 0.001). Besides, we found multiplicative interaction between rs3077 and age (≤45 years old and > 45 years old; P = 0.046). In conclusion, HLA-DP and HLA-DQ loci are candidate susceptibility regions for AML in Han Chinese.
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http://dx.doi.org/10.1016/j.prp.2020.152829DOI Listing
March 2020

Highly Efficient and High Peak Transmittance Colorful Semitransparent Organic Solar Cells with Hybrid-Electrode-Mirror Microcavity Structure.

ACS Appl Mater Interfaces 2019 Dec 16;11(51):47992-48001. Epub 2019 Dec 16.

College of Electronic Engineering , South China Agricultural University , Guangzhou 510642 , People's Republic of China.

Microcavity is an efficient approach to manufacture colorful semitransparent organic solar cells (ST-OSCs) with high color purity by tailoring the transmission spectrum to narrow peaks. However, in this type of colorful semitransparent devices, high power conversion efficiency (PCE) and high peak transmittance are not yet simultaneously achieved. This paper proposes a new type of microcavity structure to achieve colorful ST-OSCs with both high PCE and high peak transmittance, in which a hybrid Au/Ag electrode is used as a mirror and WO is used as a spacer layer. First, it is demonstrated that the hybrid Au/Ag electrode mirror brings about an improvement of 7.7 and 5.5% for PCE and peak transmittance, respectively, when compared with those of the reference devices using the Ag electrode mirror. Specifically, the PCE of the optimized devices reaches the satisfactory value of over 9%, and the peak transmittance is over 25%. This value of PCE is the highest one reported so far for the microcavity-based ST-OSCs with the same peak transmittance. Second, it is demonstrated that the second-order resonance of the microcavity can be used to improve the color purity of green ST-OSCs by narrowing the transmission peak, and the combination of the second-order and third-order resonance can be used to construct colorful ST-OSCs with mixed colors. Thus, a novel approach is developed to tune the color of ST-OSCs, which is based on high-order resonance modes of the microcavity.
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http://dx.doi.org/10.1021/acsami.9b19174DOI Listing
December 2019

A cis-eQTL genetic variant in PLK4 confers high risk of hepatocellular carcinoma.

Cancer Med 2019 10 6;8(14):6476-6484. Epub 2019 Sep 6.

State Key Laboratory of Reproductive Medicine, Nanjing Medical University, Nanjing, China.

Purpose: The overexpression and knockdown of PLK4 were both reported to generate aneuploidy. Thus, we aimed to investigate whether genetic variants in PLK4 contribute to the development of hepatocellular carcinoma (HCC).

Methods: We evaluated associations of common variants in PLK4 and its promoter for the risk of HCC in our association study (1300 cases and 1344 controls). The genotype-tissue expression (GTEx) and The cancer genome atlas (TCGA) databases were used to quantify the expression of PLK4. Cell proliferation and migration affected by PLK4 in HCC were assessed in vitro. Drug susceptibility testing (DST) model was used to assess the sensibility of PLK4-activated HCC to CFI-400945, a small molecule inhibitor of PLK4.

Results: Herein, we found a significant association between rs3811741, located in the PLK4 intron, and liver cancer risk (OR = 1.26, P = 9.81 × 10 ). Although PLK4 expressed at lower levels in somatic tissues compared to the testis, the risk allele A of rs3811741 was associated with increased PLK4 expression in liver cancer tissues. Additionally, PLK4 high expression was remarkably associated with shortened survival of HCC (HR = 1.97, P = .001). Furthermore, overexpression of PLK4 promoted, while knockdown of PLK4 suppressed cancer cell proliferation, migration, and invasion. DST model demonstrated that CFI-400945 can effectively suppress rampant proliferation of HCC with highly expressed PLK4.

Conclusion: Taken together, our study demonstrated that PLK4 is a susceptibility gene and plays an oncogenic role in HCC. Furthermore, we identified that PLK4 sensitives HCC to CFI-400945, which may be an ideal therapy target for HCC.
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http://dx.doi.org/10.1002/cam4.2487DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797585PMC
October 2019

Interaction between the integrin Mac-1 and signal regulatory protein α (SIRPα) mediates fusion in heterologous cells.

J Biol Chem 2019 05 25;294(19):7833-7849. Epub 2019 Mar 25.

From the Center for Metabolic and Vascular Biology, School of Life Sciences, and

Macrophage fusion leading to the formation of multinucleated giant cells is a hallmark of chronic inflammation. Several membrane proteins have been implicated in mediating cell-cell attachment during fusion, but their binding partners remain unknown. Recently, we demonstrated that interleukin-4 (IL-4)-induced fusion of mouse macrophages depends on the integrin macrophage antigen 1 (Mac-1). Surprisingly, the genetic deficiency of intercellular adhesion molecule 1 (ICAM-1), an established ligand of Mac-1, did not impair macrophage fusion, suggesting the involvement of other counter-receptors. Here, using various approaches, including signal regulatory protein α (SIRPα) knockdown, recombinant proteins, adhesion and fusion assays, biolayer interferometry, and peptide libraries, we show that SIRPα, which, similar to ICAM-1, belongs to the Ig superfamily and has previously been implicated in cell fusion, interacts with Mac-1. The following results support the conclusion that SIRPα is a ligand of Mac-1: () recombinant ectodomain of SIRPα supports adhesion of Mac-1-expressing cells; () Mac-1-SIRPα interaction is mediated through the ligand-binding αI-domain of Mac-1; () recognition of SIRPα by the αI-domain conforms to general principles governing binding of Mac-1 to many of its ligands; () SIRPα reportedly binds CD47; however, anti-CD47 function-blocking mAb produced only a limited inhibition of macrophage adhesion to SIRPα; and () co-culturing of SIRPα- and Mac-1-expressing HEK293 cells resulted in the formation of multinucleated cells. Taken together, these results identify SIRPα as a counter-receptor for Mac-1 and suggest that the Mac-1-SIRPα interaction may be involved in macrophage fusion.
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http://dx.doi.org/10.1074/jbc.RA118.006314DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6514624PMC
May 2019

Association study between genetic polymorphisms in folate metabolism and gastric cancer susceptibility in Chinese Han population: A case-control study.

Mol Genet Genomic Med 2019 05 18;7(5):e633. Epub 2019 Mar 18.

Key Laboratory of Resource Biology and Biotechnology in Western China (Northwest University), Ministry of Education, School of Life Sciences, Northwest University, Xi'an, Shaanxi, China.

Background: Gastric cancer (GC), the second leading cause of cancer mortality behind lung cancer worldwide, is caused by both genetic and environmental factors. In this study, we evaluated the association between the genetic polymorphisms of methylenetetrahydrofolate reductase (MTHFR), methionine synthesis reductase (MTR), and methyltransferase reductase (MTRR) genes and ischemic stroke risk in Chinese population.

Methods: A case-control study was conducted including 681 patients with GC and 756 healthy controls. Chi-squared test/Fisher's exact test and genetic model were used to evaluate associations. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using unconditional logistic regression.

Results: In the allele model, using the chi-square test, we found that the rs1532268 in MTRR with a minor allele T was significantly associated with increased risk of GC (OR = 1.24, 95% CI, 1.00-1.53; p = 0.048). In the genetic model analysis, we identified that the single-nucleotide polymorphism of the rs1801133 in MTHFR could increase the GC risk in the recessive model (OR = 1.31, 95% CI, 1.01-1.70; p = 0.042) and log-additive model (OR = 1.19, 95% CI, 1.02-1.38; p = 0.025). In MTHFR, a strong linkage of rs2274976 and rs1801133 was detected. The haplotype "GC" in the MTHFR gene was found to prominently increase the risk of GC (OR = 1.26, 95% CI: 1.07-1.47; p = 0.005). Other haplotypes did not display the correlativity.

Conclusion: This study suggested that MTR and MTHFR polymorphisms may contribute to increase the risk of GC.
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http://dx.doi.org/10.1002/mgg3.633DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6503009PMC
May 2019

A comparative study of pig manure with different waste straws in an ectopic fermentation system with thermophilic bacteria during the aerobic process: Performance and microbial community dynamics.

Bioresour Technol 2019 Jun 9;281:202-208. Epub 2019 Jan 9.

Institute of Plant Protection and Microbiology, Zhejiang Academy of Agriculture Science, Hangzhou, Zhejiang, PR China. Electronic address:

In the present study, ectopic fermentation systems were treated with both solid and liquid waste from livestock. Then, the various physicochemical properties and compositions of microbial communities in different waste straws treatments were compared. The addition of thermophilic bacteria was beneficial to the decomposition of litter, and it improved the fermentation process. Proteobacteria, Bacteroidetes, and Firmicutes were the predominant types in the fermentation vessels, and the presence of the phyla Proteobacteria and Bacteroidetes was correlated with factors prevailing in the mature phase. Furthermore, pig manure with sawdust, rape stem, and rice chaff and pig manure with sawdust, rice straw, and rice chaff vessels had higher concentrations of dissolved nitrogen, which were conducive to the conversion of fermentation wastes into useful fertilizer. These results demonstrate the feasibility of using rape stem and rice straw as padding materials during the treatment of both liquid and solid livestock waste in ectopic fermentation systems.
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http://dx.doi.org/10.1016/j.biortech.2019.01.029DOI Listing
June 2019

Spatially resolved temperature measurement in the carbon dioxide arc under different gas pressures.

Appl Opt 2018 Jul;57(21):6004-6009

Carbon dioxide (CO) is a promising alternative to sulfur hexafluoride for high-voltage circuit breaker applications. It is important to have a detailed understanding of CO arc properties. In this paper, radial temperature distribution of the free burning direct current arc in pure CO was investigated. Optical emission spectrometry was applied under different pressures (0.5 atm, 1 atm, and 1.5 atm) and at different axial positions (1 mm, 2 mm, 3 mm above the cathode). Assuming local thermodynamic equilibrium, the Fowler-Milne method was adopted for O I 715.67 nm and O I 777.19 nm in the periphery of the arc, and the single-line method was adopted for C II 657.81 nm near the center of the arc. Radial temperature profiles obtained by these two methods were combined at the position where normal temperature was assigned. The results indicate that near the center of the arc, higher pressure would lead to lower temperature; as the distance from the cathode to the position measured increases, the maximum temperature in the arc center would decrease. In addition, the temperature would decrease more sharply toward the periphery if the central temperature of the arc is higher.
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http://dx.doi.org/10.1364/AO.57.006004DOI Listing
July 2018

Sensor-regulator and RNAi based bifunctional dynamic control network for engineered microbial synthesis.

Nat Commun 2018 08 2;9(1):3043. Epub 2018 Aug 2.

School of Chemical, Materials and Biomedical Engineering, College of Engineering, The University of Georgia, Athens, GA, 30602, USA.

Writing artificial logic and dynamic function into complex cellular background to achieve desired phenotypes or improved outputs calls for the development of new genetic tools as well as their innovative use. In this study, we present a sensor-regulator and RNAi-based bifunctional dynamic control network that can provide simultaneous upregulation and downregulation of cellular metabolism for engineered biosynthesis. The promoter-regulator-mediated upregulation function and its transduced downregulation function through RNAi are systematically verified and characterized. We apply this dynamic control network to regulate the phosphoenolpyruvate metabolic node in Escherichia coli and achieve autonomous distribution of carbon flux between its native metabolism and the engineered muconic acid biosynthetic pathway. This allows muconic acid biosynthesis to reach 1.8 g L. This study also suggests the circumstances where dynamic control approaches are likely to take effects.
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http://dx.doi.org/10.1038/s41467-018-05466-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6072776PMC
August 2018

Reducing residential mortgage default: Should policy act before or after home purchases?

PLoS One 2018 19;13(7):e0200476. Epub 2018 Jul 19.

Department of Agricultural and Applied Economics, The University of Georgia, Athens, Georgia, United States of America.

We examine two possible approaches to reducing residential mortgage default using a dynamic model of heterogeneous infinitely-lived agents acting optimally subject to uninsurable idiosyncratic earnings shocks and systemic house price shocks. We find higher down payments are very effective in minimizing residential mortgage foreclosures, even in periods of house price declines and recessions. In contrast, the length of the credit exclusionary period for people who experience bankruptcy or foreclosure has a much smaller impact on mortgage defaults. Thus, it is much more effective to prevent mortgage default before the mortgage closes than to pressure homeowners not to default once they are in financial trouble. This also suggests a major aspect of credit scores and credit policy is non-productive and punitive, harming people in return for little societal gain.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0200476PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6053153PMC
January 2019

Prevalence and patterns of drug resistance among pulmonary tuberculosis patients in Hangzhou, China.

Antimicrob Resist Infect Control 2018 2;7:61. Epub 2018 May 2.

1Hangzhou Center for Disease Control and Prevention, Mingshi Road, Hangzhou City, 310021 Zhejiang Province China.

Background: To evaluate prevalence and patterns of drug resistance among pulmonary tuberculosis (TB) patients in Hangzhou City, China.

Methods: Sputum samples of smear positive TB patients enrolled in 2011 and 2015 were collected and tested for drug susceptibility, and demographic and medical record data were extracted from the electronic database of China Information System for Disease Control and Prevention. Chi-square test was used to compare drug resistance prevalence between new and treated patients and between male and female patients, and Chi-square test for trend was used to compare the prevalence over calendar years 2011 and 2015.

Results: Of 1326 patients enrolled in 2015, 22.3% had resistance to any first-line anti-TB drugs and 8.0% had multi-drug resistance (MDR); drug resistance rates among previously treated cases were significantly higher than among new cases. Significant declines of resistance to isoniazid, rifampin, ethambutol and streptomycin, and MDR from 2011 to 2015 were observed among previously treated patients, while a significant decline of resistance to rifampin was observed among new cases.

Conclusions: While the prevalence of acquired drug resistance decreased due to due to implementation of DOTS-Plus program, the prevalence of primary drug resistance due to transmission remained high. Greater efforts should be made to screen drug resistance for case finding and to reduce transmission through improving the treatment and management of drug-resistant patients.
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http://dx.doi.org/10.1186/s13756-018-0348-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5930636PMC
July 2019

Two-dimensional simulation of eccentric photorefraction images for ametropes: factors influencing the measurement.

Ophthalmic Physiol Opt 2018 07 7;38(4):432-446. Epub 2018 May 7.

School of Optometry, Indiana University, Bloomington, USA.

Purpose: Eccentric photorefraction and Purkinje image tracking are used to estimate refractive state and eye position simultaneously. Beyond vision screening, they provide insight into typical and atypical visual development. Systematic analysis of the effect of refractive error and spectacles on photorefraction data is needed to gauge the accuracy and precision of the technique.

Methods: Simulation of two-dimensional, double-pass eccentric photorefraction was performed (Zemax). The inward pass included appropriate light sources, lenses and a single surface pupil plane eye model to create an extended retinal image that served as the source for the outward pass. Refractive state, as computed from the luminance gradient in the image of the pupil captured by the model's camera, was evaluated for a range of refractive errors (-15D to +15D), pupil sizes (3 mm to 7 mm) and two sets of higher-order monochromatic aberrations. Instrument calibration was simulated using -8D to +8D trial lenses at the spectacle plane for: (1) vertex distances from 3 mm to 23 mm, (2) uncorrected and corrected hyperopic refractive errors of +4D and +7D, and (3) uncorrected and corrected astigmatism of 4D at four different axes. Empirical calibration of a commercial photorefractor was also compared with a wavefront aberrometer for human eyes.

Results: The pupil luminance gradient varied linearly with refractive state for defocus less than approximately 4D (5 mm pupil). For larger errors, the gradient magnitude saturated and then reduced, leading to under-estimation of refractive state. Additional inaccuracy (up to 1D for 8D of defocus) resulted from spectacle magnification in the pupil image, which would reduce precision in situations where vertex distance is variable. The empirical calibration revealed a constant offset between the two clinical instruments.

Conclusions: Computational modelling demonstrates the principles and limitations of photorefraction to help users avoid potential measurement errors. Factors that could cause clinically significant errors in photorefraction estimates include high refractive error, vertex distance and magnification effects of a spectacle lens, increased higher-order monochromatic aberrations, and changes in primary spherical aberration with accommodation. The impact of these errors increases with increasing defocus.
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http://dx.doi.org/10.1111/opo.12563DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097238PMC
July 2018
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