Publications by authors named "Pei Zhao"

210 Publications

A comparative study of [Ag(PrS)(dppb)] and [AgS(BuS)(dppb)]: templating effect on structure and photoluminescence.

Dalton Trans 2021 Jul 15. Epub 2021 Jul 15.

State Key Laboratory of Materials Processing and Die & Mould Technology, School of Materials Science and Engineering, Huazhong University of Science and Technology (HUST), Wuhan 430074, China.

Atomically precise silver clusters with tunable photoluminescence (PL) properties have attracted extensive attention due to their great value for basic science and future applications. Here, we report that the addition of a sulfido template into a triangular thiolated silver cluster [Ag11(iPrS)9(dppb)3]·2CF3SO3·CH3OH (Ag11, dppb = 1,4-bis(diphenylphosphino)butane), which is emissive at 660 nm under ambient conditions, produced another silver cluster [[email protected](sBuS)12(dppb)3]·CF3SO3·H2O (Ag15) that displays 716 nm emission with a 56 nm redshift aided by the ligand sec-butyl mercaptan. The sulfido template, which affects the geometrical and electronic structures, results in a redshift of Ag11 room-temperature PL as a result of opening up the template-to-metal charge transfer (TMCT) and disturbing the electronic transition between the metal core and ligands at the periphery.
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http://dx.doi.org/10.1039/d1dt01111aDOI Listing
July 2021

Genome-Wide Study of NOT2_3_5 Protein Subfamily in Cotton and Their Necessity in Resistance to .

Int J Mol Sci 2021 May 26;22(11). Epub 2021 May 26.

State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang 455000, China.

The Negative on TATA-less (NOT) 2_3_5 domain proteins play key roles in mRNA metabolism and transcription regulation, but few comprehensive studies have focused on this protein family in plants. In our study, a total of 30 genes were identified in four cotton genomes: , , and Phylogenetic analysis showed that all the NOT2_3_5 domain proteins were divided into two classes. The genes were expanded frequently, and segmental duplication had significant effects in their expansion process. The -regulatory elements analysis of promoter regions indicated that NOT2_3_5 domain proteins might participate in plant growth and development processes and responds to exogenous stimuli. Expression patterns demonstrated that all of the genes were expressed in the majority of tissues and fiber development stages, and that these genes were induced by multiple stresses. Quantitative real-time PCR showed that genes were up-regulated in response to verticillium wilt and the silencing of and led to more susceptibility to verticillium wilt than controls. Identification and analysis of the NOT2_3_5 protein family will be beneficial for further research on their biological functions.
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http://dx.doi.org/10.3390/ijms22115634DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8198034PMC
May 2021

Value of passive anterior tibial subluxation on axial MRI in identifying anterior cruciate ligament functional deficiency in patients with advanced anteromedial osteoarthritis of the knee: a case-control study.

BMC Musculoskelet Disord 2021 May 13;22(1):434. Epub 2021 May 13.

Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.

Background: A functionally deficient anterior cruciate ligament (ACL) is considered one of the contraindications in unicompartmental knee arthroplasty (UKA). But there is still a lack of standardized and reproducible methods to assess ACL functional integrity in patients with advanced anteromedial osteoarthritis of the knee (AMOA). This study explores the value of passive anterior tibial subluxation (PATS) on axial MRI in evaluating ACL status in this population.

Methods: Patients who met UKA indications between November 2017 and September 2020 were included and grouped into "intact" (ACLI) or "deficient" (ACLD) group according to their ACL status during surgery. All participants underwent MRI with a standardized protocol. The measurements of medial and lateral PATS were conducted on axial MRI, and the mean of them was calculated as global PATS. Then the reliability and diagnostic ability of PATS were determined.

Results: A total of 85 patients (45 for ACLI group, 40 for ACLD group) were included after selection. The measurements of PATS showed excellent intra- and inter-observer reliabilities (with an intraclass correlation coefficient of at least 0.986). The global PATS of the ACLI group was significantly lower than that of the ACLD group (- 2.30 ± 1.96 vs. 1.03 ± 1.96 mm, P<0.0001). The diagnostic ability of global PATS was good (area under the curve = 0.897), and a threshold of 1.2 mm had a specificity of 100%, a sensitivity of 55%, and an accuracy of 78.82%.

Conclusion: An axial global PATS of 1.2 mm on MRI is greatly specific for identifying a functionally deficient ACL in patients with advanced AMOA.
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http://dx.doi.org/10.1186/s12891-021-04328-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8120852PMC
May 2021

Ipsilateral patellofemoral morphological abnormalities are more severe than those of contralateral joints in patients with unilateral patellar dislocation.

Knee Surg Sports Traumatol Arthrosc 2021 Aug 9;29(8):2709-2716. Epub 2021 Apr 9.

Department of Orthopaedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, 400016, China.

Purpose: To determine the differences in anatomic parameters between ipsilateral dislocated knees and contralateral non-dislocated knees in patients with unilateral patellar dislocation and to identify any variations in ipsilateral knees contributing to contralateral anatomic abnormalities.

Methods: A total of 82 patients with unilateral patellar dislocation from 2016 to 2019 were retrospectively evaluated. Bilateral anatomic factors, including the tibial tubercle to trochlear groove (TT-TG) distance, lower limb rotational deformities, trochlear dysplasia, patella tilt, and patellar height, were assessed by CT.

Results: The study included 46 patients (32 females and 14 males, mean age ± SD 20.5 ± 6.8). The interobserver reliability of each parameter showed excellent agreement. The ipsilateral TT-TG distance (P = 0.004), patella tilt (P = 0.001), and patellar height (P = 0.01) were greater in the ipsilateral knees than in the contralateral knees. The lateral trochlea inclination (LTI) in the contralateral knees was larger than that in the ipsilateral knees (P = 0.022). There was a significant difference in the distribution of trochlear dysplasia of Dejour between the ipsilateral knees (dislocated side) and the contralateral knees (P = 0.036). However, bilateral femoral and/or tibial torsion, and bilateral knee joint rotation did not differ significantly. Binary logistic regression showed that only ipsilateral LTI revealed significant ORs of 8.83 (P = 0.016) and 7.64 (P = 0.018) with regard to contralateral abnormal tibial torsion and LTI, respectively.

Conclusion: In patients with unilateral patellar dislocation, the ipsilateral TT-TG distance, patella tilt, and patellar height values were larger in the ipsilateral knees than in the contralateral knees, and trochlear dysplasia was more severe in the ipsilateral joints. The risks of contralateral pathological tibial torsion and LTI were 8.8- and 7.6-fold higher, respectively, in patients with abnormal ipsilateral LTI.

Level Of Evidence: Level IV.
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http://dx.doi.org/10.1007/s00167-021-06539-2DOI Listing
August 2021

Association Between Low-Density Lipoprotein Cholesterol and Platelet Distribution Width in Acute Ischemic Stroke.

Front Neurol 2021 5;12:631227. Epub 2021 Mar 5.

Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, China.

Elevated low-density lipoprotein cholesterol (LDL-C) is an established risk factor for ischemic stroke; however, whether LDL-C affects the platelet deformation function in the peripheral blood circulation in patients with acute ischemic stroke (AIS) is unknown. The present study aimed to investigate the relationship between LDL-C and platelet distribution width (PDW) in AIS patients. We conducted a cross-sectional hospitalized-based study of consecutive 438 patients with AIS within 24 h. Blood samples were collected upon admission and prior to drug administration, and LDL-C and PDW (a parameter that reflects the heterogeneity of platelet volume) were assessed. The relationship between LDL-C and PDW were analyzed by linear curve fitting analyses. Crude and adjusted beta coefficients of LDL-C for PDW with 95% confidence intervals were analyzed using multivariate-adjusted linear regression models. The PDW was significantly higher in the high LDL-C group compared with those in the normal LDL-C group (16.28 ± 0.37 fl vs. 16.08 ± 0.37 fl, < 0.001). Adjusted smoothed plots suggested that there are linear relationships between LDL-C and PDW, and the Pearson's correlation coefficient (95%) was 0.387 (0.304-0.464, < 0.001). The beta coefficients (95% CI) between LDL-C and PDW were 0.15 (0.12-0.18, < 0.001) and 0.14 (0.11-0.18, < 0.001), respectively, in AIS patients before and after adjusting for potential confounders. Our study suggested that the elevated LDL-C level was related to increased PDW among AIS patients.
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http://dx.doi.org/10.3389/fneur.2021.631227DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7973264PMC
March 2021

iLearnPlus: a comprehensive and automated machine-learning platform for nucleic acid and protein sequence analysis, prediction and visualization.

Nucleic Acids Res 2021 06;49(10):e60

Monash Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Melbourne, VIC 3800, Australia.

Sequence-based analysis and prediction are fundamental bioinformatic tasks that facilitate understanding of the sequence(-structure)-function paradigm for DNAs, RNAs and proteins. Rapid accumulation of sequences requires equally pervasive development of new predictive models, which depends on the availability of effective tools that support these efforts. We introduce iLearnPlus, the first machine-learning platform with graphical- and web-based interfaces for the construction of machine-learning pipelines for analysis and predictions using nucleic acid and protein sequences. iLearnPlus provides a comprehensive set of algorithms and automates sequence-based feature extraction and analysis, construction and deployment of models, assessment of predictive performance, statistical analysis, and data visualization; all without programming. iLearnPlus includes a wide range of feature sets which encode information from the input sequences and over twenty machine-learning algorithms that cover several deep-learning approaches, outnumbering the current solutions by a wide margin. Our solution caters to experienced bioinformaticians, given the broad range of options, and biologists with no programming background, given the point-and-click interface and easy-to-follow design process. We showcase iLearnPlus with two case studies concerning prediction of long noncoding RNAs (lncRNAs) from RNA transcripts and prediction of crotonylation sites in protein chains. iLearnPlus is an open-source platform available at https://github.com/Superzchen/iLearnPlus/ with the webserver at http://ilearnplus.erc.monash.edu/.
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http://dx.doi.org/10.1093/nar/gkab122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8191785PMC
June 2021

Nanoporous and Highly Thermal Conductive Thin Film of Single-Crystal Covalent Organic Frameworks Ribbons.

J Am Chem Soc 2021 Mar 25;143(10):3927-3933. Epub 2021 Feb 25.

Key Laboratory for Polymeric Composite and Functional Materials of Ministry of Education, School of Chemistry, and State Key Laboratory of Optoelectronic Materials and Technologies, Sun Yat-sen University, 510275, Guangzhou, China.

Nanoporous materials are widely explored as efficient adsorbents for the storage of gases and liquids as well as for effective low-dielectric materials in large-scale integrated circuits. These applications require fast heat transfer, while most nanoporous substances are thermal insulators. Here, the oriented growth of micrometer-sized single-crystal covalent organic frameworks (COFs) ribbons with nanoporous structures at an air-water interface is presented. The obtained COFs ribbons are interconnected into a continuous and purely crystalline thin film. Due to the robust connectivity among the COFs ribbons, the entire film can be easily transferred and reliably contacted with target supports. The measured thermal conductivity amounts to ∼5.31 ± 0.37 W m K at 305 K, which is so far the highest value for nanoporous materials. These findings provide a methodology to grow and assemble single-crystal COFs into large area ensembles for the exploration of functional properties and potentially lead to new devices with COFs thin films where both porosity and thermal conductivity are desired.
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http://dx.doi.org/10.1021/jacs.0c13458DOI Listing
March 2021

Investigation of the Stereochemical Mechanism of the Nucleophilic Substitution Reaction at Pentacoordinate Phosphorus of Spirophosphorane.

J Org Chem 2021 Mar 17;86(6):4512-4531. Epub 2021 Feb 17.

Green Catalysis Center, College of Chemistry, Zhengzhou University, Kexue Road No. 100, Zhengzhou 450001, China.

The stereochemical mechanism of the nucleophilic substitution reaction at pentacoordinate phosphorus (P-V) atom is rarely studied. Here, we report the Atherton-Todd-type reaction of pentacoordinate hydrospirophosphorane with phenolic compounds in detail. The stereochemical mechanism of nucleophilic substitution at P-V atom was proposed by P NMR tracing experiment, X-ray diffraction analysis, and density functional theory calculations. The first step of the Atherton-Todd-type reaction is the formation of halogenated spirophosphorane intermediate with retention of configuration at phosphorus definitely. The second step is a nucleophilic substitution reaction at P-V atom of halogenated spirophosphorane. When using CCl as a halogenating agent, the reaction of chlorinated spirophosphorane proceeds via S2(P-V) mechanism, and the backside attack of P-Cl bond is the main pathway. For chlorinated spirophosphorane with Δ configuration, the completely P-inverted product is normally obtained. As for chlorinated spirophosphorane with Λ configuration, which has larger steric hindrance behind P-Cl bond, the proportion of P-retained products apparently increases and a pair of diastereoisomers is acquired. Furthermore, if CBr is used as a halogenating agent, the nucleophilic substitution reaction of brominated spirophosphorane may go through a S1(P-V) mechanism to afford a pair of diastereoisomers.
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http://dx.doi.org/10.1021/acs.joc.0c02953DOI Listing
March 2021

Identification of SLED1 as a Potential Predictive Biomarker and Therapeutic Target of Post-Infarct Heart Failure by Bioinformatics Analyses.

Int Heart J 2021 ;62(1):23-32

Department of Cardiology, The Affiliated Hospital of Yangzhou University, Yangzhou University.

The aim of this study was to explore potential predictive biomarkers and therapeutic targets of post-infarct heart failure (HF) using bioinformatics analyses.CEL raw data of GSE59867 and GSE62646 were downloaded from the GEO database. Differentially expressed genes (DEGs) between patients with ST-segment elevation myocardial infarction (STEMI) and those with stable coronary artery disease (CAD) at admission and DEGs between admission and 6 months after myocardial infarction (MI) in patients with STEMI were analyzed. A gene ontology (GO) analysis and a gene set enrichment analysis (GSEA) were performed, and a protein-protein interaction network was constructed. Critical genes were further analyzed.In total, 147 DEGs were screened between STEMI and CAD at admission, and 62 DEGs were identified in patients with STEMI between admission and 6 months after MI. The results of GO and GSEA indicate that neutrophils, neutrophil-related immunity responses, and monocytes/macrophages play important roles in MI pathogenesis. SLED1 expression was higher in patients with HF than in those without HF at admission and 1 month after MI. GSEA indicates that mTORC1 activation, E2F targets, G2M checkpoint, and MYC targets v1 inhibition may play key roles in the development of post-infarct HF. Furthermore, SLED1 may be involved in the development of post-infarct HF by activating mTORC1 and inhibiting E2F targets, G2M checkpoint, and MYC targets v1.SLED1 may be a novel biomarker of post-infarct HF and may serve as a potential therapeutic target in this disease.
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http://dx.doi.org/10.1536/ihj.20-439DOI Listing
February 2021

Ophiopogonin D alleviates diabetic myocardial injuries by regulating mitochondrial dynamics.

J Ethnopharmacol 2021 May 22;271:113853. Epub 2021 Jan 22.

Department of Pathology, Shanghai University of Traditional Chinese Medicine, Shanghai, China. Electronic address:

Ethnopharmacological Relevance: Ophiopogonin D (OP-D) is a steroidal saponin extracted from Ophiopogon japonicus (Thunb.) Ker Gawl. (Liliaceae), that has been traditionally used to treat cough, sputum, and thirst in some Asian countries. Recently, various pharmacological roles of OP-D have been identified, including anti-inflammatory, cardioprotective, and anti-cancer effects. However, whether OP-D can prevent diabetic myocardial injury remains unknown.

Aim Of The Study: In this study, we aimed to observe the effects of OP-D on the diabetic myocardium.

Materials And Methods: Leptin receptor-deficient db/db mice were used as an animal model for type 2 diabetes. The effects of OP-D on blood glucose, blood lipids, myocardial ultrastructure, and mitochondrial function in mice were observed after four weeks of intragastric administration. Palmitic acid was used to stimulate cardiomyocytes to establish a myocardial lipotoxicity model. Cell apoptosis, mitochondrial morphology, and function were observed.

Results: Blood glucose and blood lipid levels were significantly increased in db/db mice, accompanied by myocardial mitochondrial injury and dysfunction. OP-D treatment reduced blood lipid levels in db/db mice and relieved mitochondrial injury and dysfunction. OP-D inhibited palmitic acid induced-mitochondrial fission and dysfunction, reduced endogenous apoptosis, and improved cell survival rate in H9C2 cardiomyocytes. Both in vivo and in vitro models showed increased phosphorylation of DRP1 at Ser-616, reduced phosphorylation of DRP1 at Ser-637, and reduced expression of fusion proteins MFN1/2 and OPA1. Meanwhile, immunofluorescence co-localization analysis revealed that palmitic acid stimulated the translocation of DRP1 protein from the cytoplasm to the mitochondria in H9C2 cardiomyocytes. The imbalance of mitochondrial dynamics, protein expression, and translocation of DRP1 were effectively reversed by OP-D treatment. In isolated mice ventricular myocytes, palmitic acid enhanced cytoplasmic Ca levels and suppressed contractility in ventricular myocytes, accompanied by activation of calcineurin, a key regulator of DRP1 dephosphorylation at Ser-637. OP-D reversed the changes caused by palmitic acid.

Conclusions: Our findings indicate that OP-D intervention could alleviate lipid accumulation and mitochondrial injury in diabetic mouse hearts and palmitic acid-stimulated cardiomyocytes. The cardioprotective effect of OP-D may be mediated by the regulation of mitochondrial dynamics.
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http://dx.doi.org/10.1016/j.jep.2021.113853DOI Listing
May 2021

Stabilities, Electronic Structures, and Bonding Properties of 20-Electron Transition Metal Complexes (Cp)TMO and their One-Dimensional Sandwich Molecular Wires (Cp = CH, C(CH)H, C(CH); TM = Cr, Mo, W).

J Phys Chem A 2021 Jan 19;125(3):721-730. Epub 2021 Jan 19.

MOE Key Laboratory for Non-Equilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University, Xi'an 710049, Shaanxi, China.

First-principles calculations have been carried out for the 20-electron transition metal complexes (Cp)TMO and their molecular wires (Cp = CH, C(CH)H, C(CH); TM = Cr, Mo, W). The calculation results at the BP86/def2-TZVPP level reveal that the ground state is singlet and the optimized geometries are in good agreement with the experimental values. The analysis of frontier molecular orbitals shows that two electrons in the highest occupied molecular orbital HOMO-1 are mainly localized on cyclopentadienyl and oxygen ligands. Furthermore, the nature of the TM-O bond was investigated with the energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV). The attraction term in the intrinsic interaction energies Δ is mainly composed of two important parts, including electrostatic interaction (about 52% of the total attractive interactions Δ + Δ) and orbital interaction, which might be the major determinant of the stability of these (Cp)TMO complexes. All of the TM-O bonds should be described as electron-sharing σ single bonds [(Cp)TM]-[O] with the contribution of 53-57% of Δ and two π backdonations from the occupied p orbitals of oxygen ligands into vacant π* MOs of the [(Cp)TM] fragments, which are 35-40% of Δ. The results of bond order and interaction energy from EDA-NOCV calculations suggest the influence of the radius of TM and methyl in the interactions between TM and O in (Cp)TMO. Additionally, the relativistic effects slightly amplify the strength of bonding with increasing Δ for the EDA-NOCV calculations on three metal complexes (CH)TMO. Finally, the geometries, electronic structures, and magnetics of infinitely extended systems, [(CH)TMO], have also been explored. The results of the density of states (DOS) and band structure revealed that [(CH)CrO] and [(CH)WO] are semiconductors with the narrow bands, whereas [(CH)MoO] behaves as metal.
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http://dx.doi.org/10.1021/acs.jpca.0c07402DOI Listing
January 2021

Detection of candidate genes and development of KASP markers for Verticillium wilt resistance by combining genome-wide association study, QTL-seq and transcriptome sequencing in cotton.

Theor Appl Genet 2021 Apr 12;134(4):1063-1081. Epub 2021 Jan 12.

State Key Laboratory of Cotton Biology, Institute of Cotton Research, Chinese Academy of Agricultural Sciences, Anyang, Henan, China.

Key Message: Combining GWAS, QTL-seq and transcriptome sequencing detected basal defense-related genes showing gDNA sequence variation and expression difference in diverse cotton lines, which might be the molecular mechanisms of VW resistance in G. hirsutum. Verticillium wilt (VW), which is caused by the soil-borne fungus Verticillium dahliae, is a major disease in cotton (Gossypim hirsutum) worldwide. To facilitate the understanding of the genetic basis for VW resistance in cotton, a genome-wide association study (GWAS), QTL-seq and transcriptome sequencing were performed. The GWAS of VW resistance in a panel of 120 core elite cotton accessions using the Cotton 63K Illumina Infinium SNP array identified 5 QTL from 18 significant SNPs meeting the 5% false discovery rate threshold on 5 chromosomes. All QTL identified through GWAS were found to be overlapped with previously reported QTL. By combining GWAS, QTL-seq and transcriptome sequencing, we identified eight candidate genes showing both gDNA sequence variation and expression difference between resistant and susceptible lines, most related to transcription factors (TFs), flavonoid biosynthesis and those involving in the plant basal defense and broad-spectrum disease resistance. Ten KASP markers were successfully validated in diverse cotton lines and could be deployed in marker-assisted breeding to enhance VW resistance. These results supported our inference that the gDNA sequence variation or expression difference of those genes involving in the basal defense in diverse cotton lines might be the molecular mechanisms of VW resistance in G. hirsutum.
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http://dx.doi.org/10.1007/s00122-020-03752-4DOI Listing
April 2021

Microfluidic Technology for Antibacterial Resistance Study and Antibiotic Susceptibility Testing: Review and Perspective.

ACS Sens 2021 01 18;6(1):3-21. Epub 2020 Dec 18.

Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.

A review on microfluidic technology for antibacterial resistance study and antibiotic susceptibility testing (AST) is presented here. Antibiotic resistance has become a global health crisis in recent decades, severely threatening public health, patient care, economic growth, and even national security. It is extremely urgent that antibiotic resistance be well looked into and aggressively combated in order for us to survive this crisis. AST has been routinely utilized in determining bacterial susceptibility to antibiotics and identifying potential resistance. Yet conventional methods for AST are increasingly incompetent due to unsatisfactory test speed, high cost, and deficient reliability. Microfluidics has emerged as a powerful and very promising platform technology that has proven capable of addressing the limitation of conventional methods and advancing AST to a new level. Besides, potential technical challenges that are likely to hinder the development of microfluidic technology aimed at AST are observed and discussed. To conclude, it is noted that (1) the translation of microfluidic innovations from laboratories to be ready AST platforms remains a lengthy journey and (2) ensuring all relevant parties engaged in a collaborative and unified mode is foundational to the successful incubation of commercial microfluidic platforms for AST.
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http://dx.doi.org/10.1021/acssensors.0c02175DOI Listing
January 2021

Stabilities, Electronic Structures, and Bonding Properties of Iron Complexes (EE)Fe(CO)(CNAr) (EE=BF, CO, N, CN, or NO).

ChemistryOpen 2020 11 18;9(11):1195-1201. Epub 2020 Nov 18.

MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, School of Physics, Xi'an Jiaotong University.

The coordination of 10-electron diatomic ligands (BF, CO N) to iron complexes Fe(CO)(CNAr) [Ar=2,6-(2,4,6-(-propyl)CH)CH] have been realized in experiments very recently (, , , 1203-1205). Herein, the stability, electronic structures, and bonding properties of (EE)Fe-(CO)(CNAr) (EE=BF, CO, N, CN, NO) were studied using density functional (DFT) calculations. The ground state of all those molecules is singlet and the calculated geometries are in excellent agreement with the experimental values. The natural bond orbital analysis revealed that Fe is negatively charged while E possesses positive charges. By employing the energy decomposition analysis, the bonding nature of the EE-Fe(CO)(CNAr) bond was disclosed to be the classic dative bond EE→Fe(CO)(CNAr) rather than the electron-sharing double bond. More interestingly, the bonding strength between BF and Fe(CO)(CNAr) is much stronger than that between CO (or N) and Fe(CO)(CNAr), which is ascribed to the better σ-donation and π back-donations. However, the orbital interactions in CN→Fe(CO)(CNAr) and NO→Fe(CO)(CNAr) mainly come from σ-donation and π back-donation, respectively. The different contributions from σ donation and π donation for different ligands can be well explained by using the energy levels of EE and Fe(CO)(CNAr) fragments.
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http://dx.doi.org/10.1002/open.202000248DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7673221PMC
November 2020

Targeting miR-18a sensitizes chondrocytes to anticytokine therapy to prevent osteoarthritis progression.

Cell Death Dis 2020 11 3;11(11):947. Epub 2020 Nov 3.

Chongqing Key Laboratory of Molecular Oncology and Epigenetics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.

Inflammation participates in the development of OA and targeting inflammatory signaling pathways is a potential strategy for OA treatment. IL-1β is one of the most important inflammatory factors to trigger the activation of NF-κB signaling and accelerate OA progression, whereas OA patients could hardly benefit from inhibiting IL-1β in clinic, suggesting the importance to further explore the details of OA inflammation. We here showed that expression of miR-18a in chondrocytes was specifically induced in response to IL-1β in vitro as well as in rat model of OA during which NF-κB signaling was involved, and that nuclear-translocated p65 directly upregulated miR-18a expression at transcriptional level. Further, increased miR-18a mediated hypertrophy of chondrocytes, resulting in OA degeneration, by targeting TGFβ1, SMAD2, and SMAD3 and subsequently leading to repression of TGF-β signaling. And the level of serum miR-18a was positively correlated to severity of OA. Interestingly, other than IL-1β, pro-inflammation cytokines involving TNFα could also remarkably upregulate miR-18a via activating NF-κB signaling and subsequently induce chondrocytes hypertrophy, suggesting a pivotal central role of miR-18a in inflammatory OA progression. Thus, our study revealed a novel convergence of NF-κB and TGF-β signaling mediated by miR-18a, and a novel mechanism underlying inflammation-regulated OA dependent of NF-κB/miR-18a/TGF-β axis. Notably, in vivo assay showed that targeting miR-18a sensitized OA chondrocytes to IL-1β inhibitor as targeting IL-1β and miR-18a simultaneously had much stronger inhibitory effects on OA progression than suppressing IL-1β alone. Therefore, the diagnostic and therapeutic potentials of miR-18a for OA were also revealed.
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http://dx.doi.org/10.1038/s41419-020-03155-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7609664PMC
November 2020

Author Correction: Genetically encoded tags for direct synthesis of EM-visible gold nanoparticles in cells.

Nat Methods 2020 Nov;17(11):1167

National Institute of Biological Sciences, Beijing, China.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
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http://dx.doi.org/10.1038/s41592-020-00996-2DOI Listing
November 2020

Inhibition of starch digestion: The role of hydrophobic domain of both α-amylase and substrates.

Food Chem 2021 Mar 28;341(Pt 1):128211. Epub 2020 Sep 28.

Molecular Food Science Laboratory, College of Food & Biology Engineering, Zhejiang Gongshang University, Hangzhou 310018, China. Electronic address:

The physicochemical mechanism of starch digestion is very complicated since it may be affected by the non-valence interactions of the amylase inhibitor with the substrate or the enzyme. The role of hydrophobic interaction in the process of starch digestion is not clear. In this study, pluronics (PLs) with different hydrophobicity were used as model amphiphilic compounds to study their inhibition on starch digestion using multi-spectroscopic methods. The results showed that the hydrophobic nature of PLs changed starch structure, but it had a greater effect on the structure of α-amylase by exposing more tryptophan residues and increasing α-helix and β-sheet contents. Further investigation by using different chain-length fatty acids confirmed the results. The finding in this study is informative to design and fabricate α-amylase inhibitors for controlling starch digestion at the molecular level.
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http://dx.doi.org/10.1016/j.foodchem.2020.128211DOI Listing
March 2021

Pulmonary hypertension due to left heart disease with pulmonary arterial wedge pressure ≤15 mm Hg.

Herz 2020 Sep 29. Epub 2020 Sep 29.

Department of Cardiology, The First Affiliated Hospital of Nanjing Medical University, Guangzhou Road 300, 210029, Nanjing, China.

Background: Pulmonary hypertension due to left heart disease (PH-LHD) is the most prevalent type of pulmonary hypertension (PH). The hemodynamic diagnostic standard of pulmonary arterial wedge pressure (PAWP) >15 mm Hg that is traditionally recommended by guidelines is being challenged.

Methods: To address this problem, we analyzed the data of 154 patients with PH-LHD admitted to our center from April 2013 to March 2018. Pharmacological or nonpharmacological treatment of underlying left heart disease was offered to all 154 patients.

Results: In total, there were 24 patients (15.6%) with PAWP ≤15 mm Hg. Comparison of echocardiography and right heart catheterization parameters between the two groups (PAWP >15 mm Hg and PAWP ≤15 mm Hg) showed that the group with PAWP ≤15 mm Hg had smaller left ventricular diameter, higher cardiac output, lower pressure and higher oxygen saturation in the pulmonary artery, right atrium, right ventricle, and superior vena cava. No significant difference was found regarding dilated cardiomyopathy, diabetes mellitus, hypertension, atrial fibrillation, and left heart valvular disease, but a significant difference was found for coronary heart disease (higher morbidity in group with PAWP ≤15 mm Hg) between the two groups.

Conclusion: We found that 15.6% of the patients with PH-LHD under pharmacological or nonpharmacological treatment had PAWP ≤15 mm Hg. These results suggest that the diagnostic criterion of PAWP and the characteristics for this group of patients should be further investigated.
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http://dx.doi.org/10.1007/s00059-020-04983-3DOI Listing
September 2020

Microfluidics-Based Systems in Diagnosis of Alzheimer's Disease and Biomimetic Modeling.

Micromachines (Basel) 2020 Aug 19;11(9). Epub 2020 Aug 19.

School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China.

Early detection and accurate diagnosis of Alzheimer's disease (AD) is essential for patient care and disease treatment. Microfluidic technology is emerging as an economical and versatile platform in disease detection and diagnosis. It can be conveniently integrated with nanotechnology and/or biological models for biomedical functional and pre-clinical treatment study. These strengths make it advantageous in disease biomarker detection and functional analysis against a wide range of biological backgrounds. This review highlights the recent developments and trends of microfluidic applications in AD research. The first part looks at the principles and methods for AD diagnostic biomarker detection and profiling. The second part discusses how microfluidic chips, especially organ-on-a-chip platforms, could be used as an independent approach and/or integrated with other technologies in AD biomimetic functional analysis.
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http://dx.doi.org/10.3390/mi11090787DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7569794PMC
August 2020

Microfluidic Technology for the Production of Well-Ordered Porous Polymer Scaffolds.

Polymers (Basel) 2020 Aug 19;12(9). Epub 2020 Aug 19.

Energy Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250014, China.

Advances in tissue engineering (TE) have revealed that porosity architectures, such as pore shape, pore size and pore interconnectivity are the key morphological properties of scaffolds. Well-ordered porous polymer scaffolds, which have uniform pore size, regular geometric shape, high porosity and good pore interconnectivity, facilitate the loading and distribution of active biomolecules, as well as cell adhesion, proliferation and migration. However, these are difficult to prepare by traditional methods and the existing well-ordered porous scaffold preparation methods require expensive experimental equipment or cumbersome preparation steps. Generally, droplet-based microfluidics, which generates and manipulates discrete droplets through immiscible multiphase flows inside microchannels, has emerged as a versatile tool for generation of well-ordered porous materials. This short review details this novel method and the latest developments in well-ordered porous scaffold preparation via microfluidic technology. The pore structure and properties of microfluidic scaffolds are discussed in depth, laying the foundation for further research and application in TE. Furthermore, we outline the bottlenecks and future developments in this particular field, and a brief outlook on the future development of microfluidic technique for scaffold fabrication is presented.
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http://dx.doi.org/10.3390/polym12091863DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564514PMC
August 2020

Genetically encoded tags for direct synthesis of EM-visible gold nanoparticles in cells.

Nat Methods 2020 09 10;17(9):937-946. Epub 2020 Aug 10.

National Institute of Biological Sciences, Beijing, China.

Genetically encoded tags for single-molecule imaging in electron microscopy (EM) are long-awaited. Here, we report an approach for directly synthesizing EM-visible gold nanoparticles (AuNPs) on cysteine-rich tags for single-molecule visualization in cells. We first uncovered an auto-nucleation suppression mechanism that allows specific synthesis of AuNPs on isolated tags. Next, we exploited this mechanism to develop approaches for single-molecule detection of proteins in prokaryotic cells and achieved an unprecedented labeling efficiency. We then expanded it to more complicated eukaryotic cells and successfully detected the proteins targeted to various organelles, including the membranes of endoplasmic reticulum (ER) and nuclear envelope, ER lumen, nuclear pores, spindle pole bodies and mitochondrial matrices. We further implemented cysteine-rich tag-antibody fusion proteins as new immuno-EM probes. Thus, our approaches should allow biologists to address a wide range of biological questions at the single-molecule level in cellular ultrastructural contexts.
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http://dx.doi.org/10.1038/s41592-020-0911-zDOI Listing
September 2020

Leveraging Population Genomics for Individualized Correction of the Hallmarks of Alpha-1 Antitrypsin Deficiency.

Chronic Obstr Pulm Dis 2020 Jul;7(3):224-246

Department of Molecular Medicine, Scripps Research, La Jolla, California.

Deep medicine is rapidly moving towards a high-definition approach for therapeutic management of the patient as an individual given the rapid progress of genome sequencing technologies and machine learning algorithms. While considered a monogenic disease, alpha-1 antitrypsin (AAT) deficiency (AATD) patients present with complex and variable phenotypes we refer to as the "hallmarks of AATD" that involve distinct molecular mechanisms in the liver, plasma and lung tissues, likely due to both coding and non-coding variation as well as genetic and environmental modifiers in different individuals. Herein, we briefly review the current therapeutic strategies for the management of AATD. To embrace genetic diversity in the management of AATD, we provide an overview of the disease phenotypes of AATD patients harboring different AAT variants. Linking genotypic diversity to phenotypic diversity illustrates the potential for sequence-specific regions of AAT protein fold design to play very different roles during nascent synthesis in the liver and/or function in post-liver plasma and lung environments. We illustrate how to manage diversity with recently developed machine learning (ML) approaches that bridge sequence-to-function-to-structure knowledge gaps based on the principle of spatial covariance (SCV). SCV relationships provide a deep understanding of the genotype to phenotype transformation initiated by AAT variation in the population to address the role of genetic and environmental modifiers in the individual. Embracing the complexity of AATD in the population is critical for risk management and therapeutic intervention to generate a high definition medicine approach for the patient.
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http://dx.doi.org/10.15326/jcopdf.7.3.2019.0167DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7857707PMC
July 2020

Stachydrine hydrochloride suppresses phenylephrine-induced pathological cardiac hypertrophy by inhibiting the calcineurin/nuclear factor of activated T-cell signalling pathway.

Eur J Pharmacol 2020 Sep 24;883:173386. Epub 2020 Jul 24.

School of Basic Medical Science, Shanghai University of Traditional Chinese Medicine, Shanghai, China. Electronic address:

The calcineurin (CaN)/nuclear factor of activated T-cell (NFAT) signalling pathway plays an important role in pathological cardiac hypertrophy. Here, we investigated the potential effects of stachydrine hydrochloride, a bioactive constituent extracted from the Chinese herb Leonurus japonicus Houtt. (Yimucao), on pathological cardiac hypertrophy during chronic α1-adrenergic receptor (α1-AR) activation and the underlying mechanisms. First, by transcriptome analysis, we determined that pathological hypertrophy models could be prepared after phenylephrine stimulation. In primary cultured neonatal rat ventricular myocytes, stachydrine hydrochloride reduced phenylephrine-induced cardiomyocyte surface area and the mRNA expression of cardiac hypertrophy biomarkers (atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), and β-myosin heavy chain/α-myosin heavy chain (β-MHC/α-MHC)). In addition, phenylephrine stimulation potently induced activation of the CaN/NFAT pathway. Interestingly, stachydrine hydrochloride inhibited CaN activation and reduced NFATc3 nuclear translocation in phenylephrine-stimulated neonatal rat ventricular myocytes. In mice treated with phenylephrine, stachydrine hydrochloride treatment decreased cardiac hypertrophy and regulated heart function. Collectively, our data show that stachydrine hydrochloride decreases cardiac hypertrophy in phenylephrine-stimulated hearts by inhibiting the CaN/NFAT pathway, which might contribute to alleviation of pathological cardiac hypertrophy and cardiac dysfunction by stachydrine hydrochloride after phenylephrine stimulation This also indicated that governing of CaN/NFAT pathway might serve as a preventive or therapeutic strategy for pathological cardiac hypertrophy.
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http://dx.doi.org/10.1016/j.ejphar.2020.173386DOI Listing
September 2020

An excitation-dependent ratiometric dual-emission strategy for the large-scale enhancement of fluorescent tint control.

Nanoscale 2020 Jun;12(24):12773-12778

State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200438, China.

An alternative and convenient strategy for preparing carbon dots (CDs) with multicolor and dual-emission fluorescence is described. For this dual-emission characteristic, the short-wavelength emission reveals unique excitation-dependent fluorescence behavior, during which the long-wavelength emission remains unshifted regardless of the excitation. Consequently, such excitation-dependent ratiometric dual emission can be applied into a fluorescent tint control of this material between the cold and warm white-light regions. This unique property allows the CDs to be further translated into film sheets for visual detection of the irradiation source, and to also be conjugated with calf thymus DNA for multichannel bioimaging. These results offer new insights for the development of easy-to-handle techniques for material luminescent color tuning.
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http://dx.doi.org/10.1039/d0nr01882aDOI Listing
June 2020

PROSPECT: A web server for predicting protein histidine phosphorylation sites.

J Bioinform Comput Biol 2020 08 5;18(4):2050018. Epub 2020 Jun 5.

Biomedicine Discovery Institute and Department of Biochemistry and Molecular Biology, Monash University, Australia.

Phosphorylation of histidine residues plays crucial roles in signaling pathways and cell metabolism in prokaryotes such as bacteria. While evidence has emerged that protein histidine phosphorylation also occurs in more complex organisms, its role in mammalian cells has remained largely uncharted. Thus, it is highly desirable to develop computational tools that are able to identify histidine phosphorylation sites. Here, we introduce PROSPECT that enables fast and accurate prediction of proteome-wide histidine phosphorylation substrates and sites. Our tool is based on a hybrid method that integrates the outputs of two convolutional neural network (CNN)-based classifiers and a random forest-based classifier. Three features, including the one-of-K coding, enhanced grouped amino acids content (EGAAC) and composition of k-spaced amino acid group pairs (CKSAAGP) encoding, were taken as the input to three classifiers, respectively. Our results show that it is able to accurately predict histidine phosphorylation sites from sequence information. Our PROSPECT web server is user-friendly and publicly available at http://PROSPECT.erc.monash.edu/. PROSPECT is superior than other pHis predictors in both the running speed and prediction accuracy and we anticipate that the PROSPECT webserver will become a popular tool for identifying the pHis sites in bacteria.
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http://dx.doi.org/10.1142/S0219720020500183DOI Listing
August 2020

Transcriptomics- and metabolomics-based integration analyses revealed the potential pharmacological effects and functional pattern of in vivo Radix Paeoniae Alba administration.

Chin Med 2020 24;15:52. Epub 2020 May 24.

Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Fudan University, 130 DongAn Ave, Xuhui, 200032 Shanghai China.

Background: Radix Paeoniae Alba (RPA) and other natural medicines have remarkable curative effects and are widely used in traditional Chinese Medicine (TCM). However, due to their multi-component and multi-target characteristics, it is difficult to study the detailed pharmacological mechanisms for those natural medicines in vivo. Therefore, their real effects on organisms is still uncertain.

Methods: RPA was selected as research object, the present study was designed to study the complex mechanisms of RPA in vivo by integrating and interpreting the transcriptomic based RNA-seq and metabolomic based NMR spectrum after RPA administration in mice. A variety of dimension-reduction algorithms and classifier models were applied to the processing of high-throughput data.

Results: Among serum metabolites, the contents of PC and glucose were significantly increased, while the contents of various amino acids, lipids and their metabolites were significantly decreased in mice after RPA administration. Based on the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases, differential analysis showed that the liver was the site where RPA exerted a significant effect, which confirmed the rationality of "meridian tropism" in the theory in TCM. In addition, RPA played a role in lipid metabolism by regulating genes encoding enzymes of the glycerolipid metabolism pathway, such as 1-acyl-sn-glycerol-3-phosphate acyltransferase (Agpat), phosphatidate phosphatase (Lpin), phospholipid phosphatase (Plpp) and endothelial lipase (Lipg). We also found that RPA regulates several substance addiction pathways in the brain, such as the cocaine addiction pathway, and the related targets were predicted based on the sequencing data from pathological model in the GEO database. The overall effective pattern of RPA was intuitively presented with a multidimensional radar map through a self-designed model which found that liver and brain were mainly regulated by RPA compared with the traditional meridian tropism theory.

Conclusions: Overall this study expanded the potential application of RPA and provided possible targets and directions for further mechanism study, meanwhile, it also established a multi-dimensional evaluation model to represent the overall effective pattern of TCM for the first time. In the future, such study based on the high-throughput data sets can be used to interpret the theory of TCM and to provide a valuable research model and clinical medication reference for the TCM researchers and doctors.
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http://dx.doi.org/10.1186/s13020-020-00330-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7245909PMC
May 2020

Impact on Short-Term Complications of Early Oral Feeding in Patients with Esophageal Cancer After Esophagectomy.

Nutr Cancer 2021 1;73(4):609-616. Epub 2020 Jun 1.

Radiation Oncology Key Laboratory of Sichuan Province, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center. School of Medicine, University of Electronic Science and Technology of China, Chengdu, China.

To evaluate early oral feeding (EOF) in short-term outcomes of patients with esophageal cancer after esophagectomy. 179 patients with esophageal cancer who underwent esophagectomy between January 2016 and February 2018 were enrolled for this study. 87 patients with EOF without nasogastric tube or nasogastric tube was removed within 24 h, were selected as the experimental group, whereas 92 patients who received nasojejunal tube feeding were set as the control group. All laboratory testing, clinical features, and hospitalization expenses were compared between the two groups. No statistical significance was observed between the two groups in hemoglobin, albumin, and prealbumin levels after esophagectomy. Notably, there was no significant difference in the incidence of severe pneumonia and anastomotic leakage between the two groups. Admittance period, postoperative defecation time, and medical expenses were significantly decreased among patients with EOF ( < 0.001). Multivariate Cox multiple-factor regression analysis revealed that there was no correlation between EOF and the risk of anastomotic leakage. EOF might not be a risk factor for increasing the incidence of severe pneumonia and anastomotic leakage in patients with esophageal cancer after esophagectomy, and it could reduce the hospitalization period as well as control medical expenses.
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http://dx.doi.org/10.1080/01635581.2020.1769690DOI Listing
June 2020

Cera alba-assisted ultraclean graphene transfer for high-performance PbI UV photodetectors.

Nanotechnology 2020 Sep 28;31(36):365204. Epub 2020 May 28.

College of Information Science and Electronic Engineering, Zhejiang University, Hangzhou 310027, People's Republic of China. State Key Laboratory of Silicon Materials, Zhejiang University, Hangzhou 310027, People's Republic of China.

Large polymer residues introduced by the graphene transfer process is still a major obstacle limiting the integration of chemical vapor deposition (CVD)-grown graphene into next-generation electronic and photoelectronic devices. Here we use cera alba, a natural and environmental-friendly material that derives from honeycomb, as the supporting layer for ultraclean graphene transfer. The transferred graphene has a low surface roughness with a surface height fluctuation within 5 nm and an only 80.08% average sheet resistance of the polymethyl methacrylate (PMMA)-transferred graphene. Further, the ultraclean graphene is used as electrodes for the PbI-based UV photodetector and enables a 135% improvement on responsivity. The cera alba assisted transfer method reported here could achieve clean and damage-free graphene transfer, promoting the application of CVD-grown two-dimensional (2D) materials in large-area thin-film electronic and optoelectronic devices.
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http://dx.doi.org/10.1088/1361-6528/ab9789DOI Listing
September 2020

Red blood cell distribution width is associated with neuronal damage in acute ischemic stroke.

Aging (Albany NY) 2020 05 23;12(10):9855-9867. Epub 2020 May 23.

Department of Neurology, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai 200127, China.

Elevated red blood cell distribution width (RDW) has been found to be associated with the occurrence of ischemic stroke. However, there is no defined relationship between RDW and neuronal damage in acute ischemic stroke (AIS). This study was designed to determine the relationship between RDW and neuronal damage in AIS patients. A total of 442 consecutive AIS patients from January 2018 to June 2019 were evaluated for neuronal damage, which was estimated by serum neuron-specific enolase (NSE) levels. Red blood cell distribution width-standard deviation (RDW-SD), a parameter that reflects the heterogeneity of red blood cell volume, was also assessed. We evaluated the association between the RDW-SD and serum NSE level through multivariate-adjusted linear regression analysis. Both the serum NSE level and the incidence of high NSE increased according to the increased RDW-SD tertile in AIS patients (<0.01). There was a positive correlation between RDW-SD and serum NSE levels (=0.275, 95% CI: 0.187-0.359, <0.001). The beta coefficients (95% CI) between RDW-SD and serum NSE levels were 0.32 (0.21-0.42, <0.001) and 0.26 (0.15-0.38, <0.001), respectively, in AIS patients before and after adjusting for potential confounders. In conclusion, we found a significant positive association between RDW-SD and neuronal damage in AIS patients.
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http://dx.doi.org/10.18632/aging.103250DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7288978PMC
May 2020

On-board monitoring (OBM) for heavy-duty vehicle emissions in China: Regulations, early-stage evaluation and policy recommendations.

Sci Total Environ 2020 Aug 28;731:139045. Epub 2020 Apr 28.

School of Environment, State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China; State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex, Beijing 100084, China.

The latest China VI emission standard has introduced a remote monitoring rule for regulating in-use emissions of heavy-duty diesel vehicles (HDDVs). Real-time data regarding engine and aftertreatment operating conditions and tailpipe nitrogen oxides (NOx) concentrations are required to be collected through electronic control unit and on-board NOx sensors by vehicle original equipment manufacturers (OEMs), and then transmitted to environmental authorities. Beijing has developed a local standard that requires OEMs to design China VI-like on-board monitoring (OBM) systems for new China V HDDVs since September 2018. Additionally, Beijing has been a pioneer in retrofitting in-use China IV and China V HDDVs with OBM systems since 2017. This paper contains a timely technical and policy assessment for the state-of-the-art OBM programs in China with a focus on the recent progress in Beijing. Both OEM-performed and retrofitted OBM data were collected from a fleet of OBM-instrumented vehicles. First, our assessment shows high data integrity and quality of OEM-performed OBM systems. In contrast, a considerable fraction of HDDVs equipped with retrofitted OBM systems did not completely report NOx concentrations, intake mass air flow and other parameters. Next, eight OBM-instrumented HDDVs were tested on road by portable emissions measurement systems (PEMSs) to examine the reliability of sensor-based NOx concentrations. The majority (6 of 8) shows a good agreement between OBM and PEMS results with an average relative error of approximately -15%. Furthermore, calculation of NOx mass emissions, inter-trip variability, and alternative methods of enforcing in-use emissions management (e.g., to develop concentration metric-based emission limits) are discussed. This early-stage assessment suggests the OBM approach has the potential to play a central role in in-use emission inspections for HDDVs in China. The regulatory agency should focus more attention to the data integrity and the reliability of NOx sensors by developing effective verification processes.
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http://dx.doi.org/10.1016/j.scitotenv.2020.139045DOI Listing
August 2020