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Biomedical subjects

Chao Yang

Publications and source records attributed to Chao Yang.

At least 19 recordsLinked to original sources
PubMed2026

Dynamics of Antibiotic Resistance Gene Profiles in Captive Forest Musk Deer (Moschus berezovskii) Along a Breeding Duration Gradient.

BACKGROUND: To conserve wild populations and ensure a sustainable supply of musk, China initiated the captive breeding of forest musk deer. The temporal dynamics of gut antibiotic resistance gene (ARG) profiles in captive forest musk deer along a breeding duration gradient remain poorly characterized. METHODS: In this study, we employed metagenomic sequencing to systematically characterize the profiles and potential mobility of ARGs. Samples were divided into short-term, medium-term and long-term groups according to breeding durations. RESULTS: A total of 331 ARG subtypes and 71 mobile genetic element (MGE) subtypes were annotated across all samples. ARG Shannon diversity differed overall across groups (Kruskal-Wallis, p = 0.03); Bonferroni-adjusted Dunn's test showed no significant pairwise differences. PCoA (Bray-Curtis) demonstrated distinct separation of the ST group (p = 0.002), and shared core ARG subtypes gradually increased with extended breeding years. A strong positive correlation between ARG and MGE abundances was identified (r = 0.85, p = 0.0001). In total, 63 contigs carrying co-localized ARG-MGE complexes were recovered. The ST group contained the highest proportion of such contigs. The ST group displayed tight physical ARG-MGE linkage within 1-3 kb genomic intervals. CONCLUSIONS: Our results reveal that breeding duration is associated with the gut ARG characteristics of captive forest musk deer. Short-term captivity has higher ARG-MGE co-localization, suggesting a higher possibility of mobilization.

One Health↗
PubMed2026

Meta-Analysis of the Efficacy of Ultrasound-Guided Mammotome Minimally Invasive Surgery and Traditional Open Surgery in the Therapy of Benign Breast Tumors.

ObjectiveTo systematically analyze the efficacy of ultrasound-guided mammotome minimally invasive surgery and traditional open surgery in the therapy of benign breast tumors.MethodsA computerized search retrieved original literature on the therapeutic effects of ultrasound-guided mammotome minimally invasive surgery and traditional open surgery for benign breast tumors from authoritative databases, including CNKI, Wanfang, VIP, Web of Science, PubMed, ScienceDirect, Cochrane Library, and Embase. The search covered from database inception to January 2024, using a strategy of subject terms combined with free terms. The retrieved literature was screened, data were extracted, and quality was evaluated. Meta-analysis was performed using RevMan 5.4 software.ResultsA total of 8 literatures were included in the study, and a total of 1909 patients with benign breast tumors were found from 2018 to 2023. The results of meta-analysis showed that the operation time [MD = -12.79, 95%CI (-14.04, -11.55), P < 0.00001], intraoperative blood loss [MD = -11.55, 95%CI (-14.74, -8.36), P < 0.00001], healing time [MD = -2.73, 95%CI (-4.03, -1.43), P < 0.00001] and complication rate [MD = 0.17, 95%CI (0.12, 0.26), P < 0.00001] was apparently different from traditional open surgery (P < 0.05).ConclusionUltrasound-guided mammotome minimally invasive surgery can effectively shorten the operation time of patients with benign breast tumors, reduce intraoperative blood loss, promote healing, and reduce the risk of complications. The effect is better than that of traditional open surgery.

Humans↗
PubMed2007

Rotational-echo double-resonance NMR distance measurements for the tubulin-bound Paclitaxel conformation.

The important anticancer drug Taxol (paclitaxel, PTX) owes its unique activity to its ability to bind to tubulin in a stoichiometric ratio and promote its assembly into microtubules. The conformation of the microtubule-bound drug has been the focus of numerous research efforts, since the inability of polymerized tubulin to form crystals precludes structure proof by X-ray crystallography. Likewise, although the alpha,beta-tubulin dimer structure has been solved by electron crystallography, the 3.7 A resolution is too low to permit direct determination of either ligand conformation or binding pose. In this article, we present experimental results from 2H{19F} REDOR NMR that provide direct confirmation that paclitaxel adopts a T-shaped conformation when it is bound to tubulin.

Animals↗
PubMed2007

Reductive transformation of parathion and methyl parathion by Bacillus sp.

Based on the results of phenotypic features, phylogenetic similarity of 16S rRNA gene sequences and BIOLOG test, a soil bacterium was identified as Bacillus sp. DM-1. Using either growing cells or a cell-free extract, it transformed parathion and methyl parathion to amino derivatives by reducing the nitro group. Pesticide transformation by a cell-free extract was specifically inhibited by three nitroreductase inhibitors, indicating the presence of nitroreductase activity. The nitroreductase activity was NAD(P)H-dependent, O(2)-insensitive, and exhibited the substrate specificity for parathion and methyl parathion. Reductive transformation significantly decreased the toxicity of pesticides.

Bacillus↗
PubMed2006

Bridging converts a noncytotoxic nor-paclitaxel derivative to a cytotoxic analogue by constraining it to the T-Taxol conformation.

The synthesis of the bridged A-nor-paclitaxel 4 has been achieved from paclitaxel in a key test of the T-Taxol conformational hypothesis. Although the unbridged A-nor-paclitaxel 3 is essentially noncytotoxic, the bridged analogue 4 is strongly cytotoxic. This result provides strong evidence for the T-Taxol conformation as the bioactive tubulin-binding conformation of paclitaxel.

Animals↗
PubMed2006

SPARX, a new environment for Cryo-EM image processing.

SPARX (single particle analysis for resolution extension) is a new image processing environment with a particular emphasis on transmission electron microscopy (TEM) structure determination. It includes a graphical user interface that provides a complete graphical programming environment with a novel data/process-flow infrastructure, an extensive library of Python scripts that perform specific TEM-related computational tasks, and a core library of fundamental C++ image processing functions. In addition, SPARX relies on the EMAN2 library and cctbx, the open-source computational crystallography library from PHENIX. The design of the system is such that future inclusion of other image processing libraries is a straightforward task. The SPARX infrastructure intelligently handles retention of intermediate values, even those inside programming structures such as loops and function calls. SPARX and all dependencies are free for academic use and available with complete source.

Computational Biology↗
PubMed2006

The parallelization of SPIDER on distributed-memory computers using MPI.

We describe the strategies and implementation details we employed to parallelize the SPIDER software package on distributed-memory parallel computers using the message passing interface (MPI). The MPI-enabled SPIDER preserves the interactive command line and batch interface used in the sequential version of SPIDER, thus does not require users to modify their existing batch programs. We show the excellent performance of the MPI-enabled SPIDER when it is used to perform multi-reference alignment and 3-D reconstruction operations on a number of different computing platforms. We point out some performance issues when the MPI-enabled SPIDER is used for a complete 3-D projection matching refinement run, and propose several ways to further improve the parallel performance of SPIDER on distributed-memory machines.

Algorithms↗
PubMed2006

Estimation of variance in single-particle reconstruction using the bootstrap technique.

Density maps of a molecule obtained by single-particle reconstruction from thousands of molecule projections exhibit strong changes in local definition and reproducibility, as a consequence of conformational variability of the molecule and non-stoichiometry of ligand binding. These changes complicate the interpretation of density maps in terms of molecular structure. A three-dimensional (3-D) variance map provides an effective tool to assess the structural definition in each volume element. In this work, the different contributions to the 3-D variance in a single-particle reconstruction are discussed, and an effective method for the estimation of the 3-D variance map is proposed, using a bootstrap technique of sampling. Computations with test data confirm the viability, computational efficiency, and accuracy of the method under conditions encountered in practical circumstances.

Algorithms↗
PubMed2006

Nerve endings of the wrist joint: a preliminary report of the dorsal radiocarpal ligament.

As part of an investigation of the articular nerve ending populations in the wrist joint capsule associated with the anterior and posterior interosseous nerves, this study addresses the nerve ending population in the dorsal radiocarpal ligament. The ligaments were harvested from four wrists of two fresh cadavers within 12 h of death. Tissues were fixed, cryostat sectioned, and processed for fluorescence immunohistochemistry using antibody to protein gene product 9.5 (PGP 9.5), a general or pan neuronal marker, and a secondary antibody conjugated to a fluorescent tag (Alexa Fluor 488). The sections were evaluated with a confocal laser microscope and an image analyzer. Labeled nerve endings were mapped, measured, and categorized. Type I (Ruffini-like ending), Type III (Golgi-like tendon organ) and Type IV (noncorpuscular) nerve endings could be identified in all four DRC ligaments, with Types I and IV dominating. These receptors were distributed primarily over the superficial two thirds of the ligament (>80%), and near the bony attachments (>70%). The dorsal radiocarpal ligament has a rich sensory innervation from the posterior interosseous nerve terminating in nerve endings located in the superficial two-thirds of the ligaments, primarily near bony attachment sites.

Aged↗
PubMed2006

In vitro fabrication of a tissue engineered human cardiovascular patch for future use in cardiovascular surgery.

BACKGROUND: One approach to tissue engineering has been the development of in vitro conditions for the fabrication of functional cardiovascular structures intended for implantation. In this experiment, we developed a pulsatile flow system that provides biochemical and biomechanical signals in order to regulate autologous, human patch-tissue development in vitro. METHODS: We constructed a biodegradable patch scaffold from porous poly-4-hydroxy-butyrate (P4HB; pore size 80 to 150 microm). The scaffold was seeded with pediatric aortic cells. The cell-seeded patch constructs were placed in a self-developed bioreactor for 7 days to observe potential tissue formation under dynamic cell culture conditions. As a control, cell-seeded scaffolds were not conditioned in the bioreactor system. After maturation in vitro, the analysis of the tissue engineered constructs included biochemical, biomechanical, morphologic, and immunohistochemical examination. RESULTS: Macroscopically, all tissue engineered constructs were covered by cells. After conditioning in the bioreactor, the cells were mostly viable, had grown into the pores, and had formed tissue on the patch construct. Electron microscopy showed confluent smooth surfaces. Additionally, we demonstrated the capacity to generate collagen and elastin under in vitro pulsatile flow conditions in biochemical examination. Biomechanical testing showed mechanical properties of the tissue engineered human patch tissue without any statistical differences in strength or resistance to stretch between the static controls and the conditioned patches. Immunohistochemical examination stained positive for alpha smooth muscle actin, collagen type I, and fibronectin. There was minor tissue formation in the nonconditioned control samples. CONCLUSIONS: Porous P4HB may be used to fabricate a biodegradable patch scaffold. Human vascular cells attached themselves to the polymeric scaffold, and extracellular matrix formation was induced under controlled biomechanical and biodynamic stimuli in a self-developed pulsatile bioreactor system.

Absorbable Implants↗
PubMed2006

Cloning of mpd gene from a chlorpyrifos-degrading bacterium and use of this strain in bioremediation of contaminated soil.

An effective chlorpyrifos-degrading bacterium (named strain YC-1) was isolated from the sludge of the wastewater treating system of an organophosphorus pesticides manufacturer. Based on the results of phenotypic features, phylogenetic similarity of 16S rRNA gene sequences and BIOLOG test, strain YC-1 was identified as the genus Stenotrophomonas. The isolate utilized chlorpyrifos as the sole source of carbon and phosphorus for its growth and hydrolyzed chlorpyrifos to 3,5,6-trichloro-2-pyridinol. Parathion, methyl parathion, and fenitrothion also could be degraded by strain YC-1 when provided as the sole source of carbon and phosphorus. The gene encoding the organophosphorus hydrolase was cloned using a PCR cloning strategy based on the known methyl parathion degrading (mpd) gene of Plesiomonas sp. M6. Sequence blast result indicated this gene has 99% similar to mpd. The inoculation of strain YC-1 (10(6) cells g(-1)) to soil treated with 100 mg kg(-1) chlorpyrifos resulted in a higher degradation rate than in noninoculated soils. Theses results highlight the potential of this bacterium to be used in the cleanup of contaminated pesticide waste in the environment.

Biodegradation, Environmental↗
PubMed2006

Large-scale synthesis of a novel tri(8-hydroxyquioline) aluminum nanostructure.

A novel tri(8-hydroxyquioline) aluminum (AlQ3) nanostructure was prepared on large scale at low cost by low-temperature physical vapor deposition (PVD). The morphologies, the chemical bondings, and photoluminescence of the AlQ3 nanostructure were investigated by environmental scanning electronic microscopy (ESEM), Fourier transform infrared spectrum (FT-IR), and photoluminescence (PL) spectra, respectively. The AlQ3 nanostructure was composed of micro-sphere with nanowire-cluster growing on the surface. The diameter of micro-sphere and nanowire were about 5 microm and 80 nm, respectively. FT-IR results indicated that the AlQ3 molecule had a strong thermal stability under research conditions. The growth mechanism of the novel nanostructure was discussed. The novel organic nanostructure would be believed to attractive building field-emission devices and other optical devices.

Aluminum↗
PubMed2006

[Preliminary study on self-concept psychological feature of cleft lip and palate adolescents].

OBJECTIVE: To obtain the self-concept psychological feature of cleft lip and palate (CLP) adolescents further and accurately, and offer reasons for timely and pointed psychological intervention. METHODS: Based on the procedure and criteria of development of psychological questionnaire, a psychological questionnaire for CLP adolescents was designed. 93 CLP and 88 healthy adolescents were studied by using it and their half-quantified score raging 0-9 were analyzed statistically. RESULTS: (1) There was no statistical difference between CLP and normal adolescents, scored 5.91 and 5.66 respectively, which demonstrated that the self-concept of CLP adolescents was at a normal level without obvious passive tendency. (2) There was no significant difference between genders, but boys were more extroversion while girls did better on being unyielding and releasing strain. (3) CLP adolescents had a higher ability of psychological regulation and could face failure more bravely. CLP patients were in a tendency of protective behavior inhibition, companied less, and maximized delight mood unconsciously to decrease harm from enviroment. (4) CLP adolescents had a good parentage. (5) A majority of patients had low expectation of life-quality. (6) Much of CLP patients considered that speech was more important than appearance. CONCLUSION: Self-concept of CLP adolescents have normal self-concept and do better in psychological regulation and dependence than normal ones.

Adolescent↗
PubMed2005

The top-bottom effect of a tilted thick specimen and its influence on electron tomography.

We present the top-bottom effect (TBE) of a 5 microm thick amorphous specimen in a 3 MV ultrahigh voltage electron microscope (ultra-HVEM) and its influence on the quality of electron tomography (ET). The 40-nm gold particles on the top surface of the specimen tilted at different angles have been observed to be of poorer image quality than those on the symmetrical bottom surface obtained by tilting and turning over the specimen. The point spread function of the gold-particle images was calculated using the increment Wiener filter and the image-quality variation was then evaluated. The TBE is shown to become more remarkable with the increase of the effective thickness of the tilted specimen or the decrease of the magnification of the ultra-HVEM. The ET simulation indicates that the TBE may generate approximately 4% distortion in the radial direction of a reconstructed sphere model.

Journal Article↗
PubMed2005

Removal of cationic dyes from aqueous solution by adsorption on peanut hull.

The potential feasibility of peanut hull particle for removal of three cationic dyes (methylene blue, brilliant cresyl blue and neutral red) from aqueous solution was investigated. The effects of various experimental parameters were examined and optimal experimental conditions were decided. Above the value of initial pH 4, three dyes studied could be removed effectively. The isothermal data fitted the Langmuir model or Freundlich model. The adsorption processes followed the pseudo-first-order rate kinetics. The results in this study indicated that peanut hull was an attractive candidate for removing cationic dyes from dye wastewater.

Adsorption↗
PubMed2005

Mirror fluid method for numerical simulation of sedimentation of a solid particle in a Newtonian fluid.

The mirror fluid method is proposed for simulating solid-fluid two-phase flow. The whole computational domain is modeled as an Eulerian one for the fluid with a Lagrangian subdomain embedded in it. The boundary condition is enforced implicitly on solid-fluid surface segments by mirror relations. Thus, the total flow is solved in the one domain, in which the solid particle region is replaced with the virtual flow as the mirror image of outside flow. The mirror fluid method is implemented to compute the motion of a rigid spherical or elliptic particle in a Newtonian fluid for the purpose of method validation. The control volume formulation with the SIMPLE algorithm incorporated is used to solve the governing equations on a staggered grid in a two-dimensional coordinate system. A number of numerical experiments on falling particles are performed and the computational results are in good agreement with the reported experimental data.

Journal Article↗
PubMed2005

Asymmetric synthesis of dihydrofurans via a formal retro-Claisen photorearrangement.

Solution-phase irradiation of a series of syn-7-benzoylnorbornene derivatives is shown to lead to cis-fused dihydrofuran derivatives in low quantum but excellent chemical yields in what is formally a retro-Claisen rearrangement. In analogy to the well-known Paterno-Buchi reaction, the first step of the rearrangement is suggested to involve (n,pi)(3)-mediated addition of the carbonyl oxygen to the norbornene double bond, producing a triplet 1,4-biradical. This intermediate, rather than closing to the oxetane, undergoes cleavage accompanied by intersystem crossing to form the dihydrofuran. To determine whether the retro-Claisen photorearrangement could be carried out enantioselectively, the 7-benzoylnorbornene reactant was equipped with a para-carboxylic acid substituent to which a series of optically pure amines was attached ionically via salt bridges. Irradiation of these salts in the crystalline state followed by diazomethane workup (the solid-state ionic chiral auxiliary method) was shown to afford the corresponding dihydrofuran in optical yields as high as 93% at 95% conversion. X-ray crystallography revealed that the enantioselectivity arises from crystallization of the reactant in a conformation in which the carbonyl oxygen is more favorably oriented for bond formation to one end of the norbornene double bond than the other, thus leading to a predominance of a single enantiomer.

Crystallography, X-Ray↗