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Biomedical subjects

Yu Bai

Publications and source records attributed to Yu Bai.

At least 19 recordsLinked to original sources

A Deep Model Framework for Morphological Trait Imputation Across Taxonomic Groups.

Incomplete morphological trait data pose major hurdles for trait-based analyses, particularly when missing values, multicollinearity, and sparse sampling constrain inference. These issues limit our ability to quantify trait variation and explore broad patterns of functional differentiation across taxa. Here, we introduce FS-DeepRBFNet, which overcomes these pitfalls through integrating correlation-based feature selection with a dual-layer adaptive radial basis function (RBF) network. This end-to-end approach effectively reduces noise and captures both linear allometric trends and nonlinear morphological relationships. We tested the framework on a large species-level morphological trait dataset of Chinese birds and further validated its cross-taxon transferability using the Amphibian Database (Caudata). FS-DeepRBFNet consistently outperformed conventional methods such as KNN, Random Forest, and XGBoost, demonstrating superior predictive accuracy across multiple traits. Beyond improvements, the model revealed biologically interpretable trait associations and stable cross-taxon generalization. These results demonstrate that FS-DeepRBFNet provides a robust and biologically grounded solution for morphological trait prediction, enabling reliable imputation for comparative phylogenetics, functional ecology, and biodiversity forecasting in data-limited situations.

cross‐taxon transferability↗

Novel serum small extracellular vesicle miRNAs with multi-target RCA-CRISPR sensor for liver cancer detection.

BACKGROUND: Detecting liver cancer (LC) remains a significant challenge in clinical practice. Small extracellular vesicle (sEV) miRNAs show promise as non-invasive biomarkers for LC detection, yet their diagnostic potential remains largely unexplored. This study aimed to identify specific sEV miRNA signatures for LC detection and develop a novel synchronized multi-miRNA detection platform to enhance diagnostic efficiency and sensitivity. METHODS: High-throughput sequencing was conducted across four distinct cohorts: normal controls (NC), hepatitis B virus (HBV) patients, liver cirrhosis patients, and LC patients. This sequencing process identified miRNAs with differential expression, followed by RT-qPCR validation in serum sEV miRNAs from LC patients and NC. An innovative detection method, RCA-CRISPR, was introduced, combining rolling circle amplification (RCA) with CRISPR/Cas12a (RCA-CRISPR) for quick and sensitive miRNAs detection. RESULTS: Sequencing results showed a consistent elevation of hsa-miR-203b-5p, hsa-miR-4661-5p, and hsa-miR-219a-2-3p across all cohorts. RT-qPCR validations confirmed significant upregulation of these miRNAs in serum sEVs from LC patients, and the combined three-miRNA panel exhibited high diagnostic accuracy (p = 0.0003; AUC = 0.81). The RCA-CRISPR method demonstrated a detection limit of 3.12 pM for simultaneous multi-target miRNA detection, highlighting its exceptional sensitivity. CONCLUSIONS: Our study identifies hsa-miR-203b-5p, hsa-miR-4661-5p, and hsa-miR-219a-2-3p as promising sEV miRNA biomarkers for LC detection. The developed RCA-CRISPR sensor provides a robust tool for multi-miRNA analysis, potentially advancing non-invasive LC diagnostics. Future validation in larger, prospectively collected cohorts is essential to establish the clinical utility and performance of this biomarker panel and RCA-CRISPR sensor.

MicroRNAs↗

Surface plasmon resonance biosensor based on Hg/Ag-Au film.

Mercury or silver was electrodeposited on an Au surface to form an Hg-Au or Ag-Au film. Wavelength-modulation SPR biosensors based on this Hg/Ag-Au film were then used to determine human IgG and rabbit IgG. When direct immunoreactions were performed on the Au sensing surface, the range of concentrations of human IgG and rabbit IgG that could be determined were 2.00-40.00 microg/ml and 2.50-40.00 microg/ml, respectively. When Hg was electrodeposited onto the Au film for 1200 s, the range of concentrations of human IgG and rabbit IgG that could be determined were 0.50-40.00 microg/ml and 0.63-40.00 microg/ml, respectively. When Ag was electrodeposited onto the Au film for 1500 s, the range of concentrations of human IgG and rabbit IgG that could be determined were 0.25-20.00 and 0.42-20.00 microg/ml, respectively. The biosensor based on Ag-Au film was therefore found to be the most sensitive of the three types of biosensor tested, giving limits of determination that were up to eight times lower than those obtained with a biosensor based on Au film alone.

Biosensing Techniques↗

2,3-Anhydrosugars in glycoside bond synthesis. Application to alpha-D-galactofuranosides.

We report here the use of 2,3-anhydro-D-gulofuranosyl thioglycosides and glycosyl sulfoxides in the synthesis of alpha-D-galactofuranosidic bonds, which are present in a range of bacterial and fungal glycoconjugates. This two-step method involves a stereoselective glycosylation in which a 2,3-anhydro-alpha-D-gulofuranoside is obtained either as the sole or as the major product, followed by a regioselective opening of the epoxide ring using lithium benzylate in the presence of (-)-sparteine. In exploring the scope of the method, donors protected at O5 and O6 with an isopropylidene acetal, benzyl ethers, or benzoate esters were studied. Overall, the glycosyl sulfoxides provided the products in slightly higher yields and selectivity, with the best results being obtained with benzylated and benzoylated substrates. In the epoxide ring-opening reactions, the acetal- and ether-protected donors afforded poor to modest regioselectivity, whereas the benzoylated products gave good yields of the desired alpha-D-galactofuranosides. The benzoyl-protected species are, therefore, the donors of choice for these reactions. The utility of the approach was demonstrated through the synthesis of three alpha-D-galactofuranosyl-containing oligosaccharides.

Carbohydrate Conformation↗

Synthesis of a pentasaccharide fragment of varianose, a cell wall polysaccharide from Penicillium varians.

The first synthesis of an oligosaccharide fragment of varianose, a polysaccharide produced by Penicillium varians, is reported. The target pentasaccharide features both alpha- and beta-galactofuranoside residues and the alpha-galactofuranoside residue is hindered, being substituted on adjacent oxygens (O1 and O2), both of which are cis to the two-carbon side chain at C4. Key features of the synthesis include a novel method for the selective protection of the C3 hydroxyl group of galactofuranosyl residues via an epoxide formation/opening sequence, the introduction of the alpha-d-galactofuranosyl residue using a 2,3-anhydrosugar donor, and the use of the 1-benzenesulfinylpiperidine/trifluoromethanesulfonic anhydride activation method for the addition of an alpha-D-glucopyranosyl residue to a hindered hydroxyl group in an advanced tetrasaccharide intermediate.

Carbohydrate Conformation↗

Determination of serum albumin in the presence of poly(diallyldimethylammonium chloride) by resonance light scattering technique.

By means of the resonance light scattering (RLS) technique, a new method was developed to determine the bovine serum albumin (BSA) and human serum albumin (HSA) by the interaction of serum albumin with poly(diallyldimethylammonium chloride) (PDDA). At Tris-NaOH buffer solution, the RLS intensity of serum albumin at the wavelength 320, 550 and 590 nm was obviously enhanced in the presence of PDDA. The influences of some experimental factors, including incubation time, addition sequence of reagents, pH value, concentration of PDDA and foreign substances, on the enhancement of the RLS intensity were examined. The optimum conditions of the experiment were selected. Under the selected experimental condition, the enhanced RLS intensities were directly proportional to the concentrations in the range of (0.0250-2.75)x10(-6) mol/L for BSA and (0.0235-1.17)x10(-6) mol/L for HSA. The detection limits (S/N=3) were 8.40x10(-9) mol/L for BSA and 7.39x10(-9) mol/L for HSA. The synthetic samples were analysed and the results obtained were satisfactory.

Animals↗

Synthesis of n-octyl 2,6-dideoxy-alpha-L-lyxo-hexopyranosyl-(1-->2)-3-amino-3-deoxy-beta-D-galactopyranoside, an analog of the H-disaccharide antigen.

The synthesis of an analog of the H-disaccharide antigen (2), in which the galactopyranosyl moiety bears an amino group at C-3 and the fucopyranosyl residue is deoxygenated at C-2, is reported. The key reaction in the preparation of 2 was the glycosylation of an appropriately protected n-octyl 3-azido-3-deoxy-galactopyranoside derivative with a 2,6-dideoxy thioglycoside promoted by 1-(phenylsulfinyl)piperidine and triflic anhydride. Disaccharide 2 is of interest in studies directed towards understanding the molecular basis of substrate recognition by the blood group A and B glycosyltransferases.

Antigens, Bacterial↗

Phylogenetic diversity of culturable bacteria from alpine permafrost in the Tianshan Mountains, northwestern China.

Microbes have been discovered in permafrost sediments for nearly a century. However, microbiological analyses of alpine permafrost are very scarce. This study is a first attempt to describe the phylogenetic diversity of a culturable bacterial community isolated from alpine permafrost in the Tianshan Mountains in northwestern China. Aerobic 2.5-6.0x10(5) CFU/gdw (CFU per 1 gram of dry weight) on modified PYGV medium were recovered from alpine permafrost samples at 4 degrees C; among these, 91 bacterial isolates with different morphotypes were characterized by phenotypic properties, such as morphology, colony pigmentation, Gram staining, endospore formation and temperature range of growth. The isolates were further categorized based on amplified rDNA restriction analysis (ARDRA), and 51 representative isolates possessing distinct ARDRA patterns selected for subsequent 16S rDNA sequencing and phylogenetic analysis. The phylogenetic trees placed the 51 isolates in four major groups: the high-G+C Gram-positives, the low-G+C Gram-positives, Proteobacteria and the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. The most abundant and diverse isolates were members of Gram-positive bacteria, particularly the Arthrobacter as a dominant group in alpine permafrost culturable populations. Results of the Jukes-Cantor evolutionary distance matrix suggested that the vast majority of the isolates were different strains of known species, and three may represent new species within the genus Chryseobacterium of the CFB phylum. From this study, it is proposed that alpine permafrost sediments in the Tianshan Mountains provide a specific ecological niche for prolonging survival of diverse microbial lineages.

Arthrobacter↗

Glucose oxidase/colloidal gold nanoparticles immobilized in Nafion film on glassy carbon electrode: Direct electron transfer and electrocatalysis.

The direct electron transfer of glucose oxidase (GOD) was achieved based on the immobilization of GOD/colloidal gold nanoparticles on a glassy carbon electrode by a Nafion film. The immobilized GOD displayed a pair of well-defined and nearly reversible redox peaks with a formal potential (Eo ') of -0.434 V in 0.1 M pH 7.0 phosphate buffer solution and the response showed a surface-controlled electrode process. The dependence of Eo ' on solution pH indicated that the direct electron transfer reaction of GOD was a two-electron-transfer coupled with a two-proton-transfer reaction process. The experimental results also demonstrated that the immobilized GOD retained its electrocatalytic activity for the oxidation of glucose. So the resulting modified electrode can be used as a biosensor for detecting glucose.

Biosensing Techniques↗

Rural and urban children with asthma: are school health services meeting their needs?

OBJECTIVE: Children with asthma spend a large portion of their day in school, and the extent to which public schools are prepared to meet their health needs is an important issue. The objective of this study was to identify asthma policies and practices in rural and urban school settings and to compare them with current National Heart, Lung, and Blood Institute recommendations. METHODS: A stratified random sample of school nurses who represented each of the 500 active Pennsylvania school districts were surveyed in 2004 concerning nurse staffing patterns, availability of asthma monitoring and treatment-related equipment, emergency preparedness, availability of asthma-related support and case management services, school-specific procedures including identification of children with asthma and accessibility of inhaler medication during school hours, presence and content of written asthma management plans, and perceived obstacles to asthma management in the school setting. Sampling weights were incorporated into the analyses to take the survey design into account. RESULTS: The overall response rate was 76%, with a total of 757 surveys analyzed. In more than half of secondary schools and three quarters of elementary schools, nurses were present < 40 hours per week. Nearly 1 in 5 schools reported that staff who know what to do for a severe asthma attack were not always available. In 72% of rural schools, children were allowed to self-carry rescue inhalers, as compared with 47% of urban schools. Asthma management plans were on file for only 1 quarter of children with asthma, and important information often was omitted. Approximately half of the schools were equipped with peak flow meters and nebulizers, and spacers were available in 1 third of schools. CONCLUSIONS: Improvements are needed to bring schools into compliance with current recommendations, including more consistent availability of knowledgeable staff, improved access to asthma monitoring and treatment-related equipment, more universal use of asthma management plans, and greater access to inhalers while at school, including increasing the proportion of children who are allowed to carry and self-administer inhaler medication.

Adolescent↗

Metal ion extraction using newly-synthesized bipyridine derivative as a chelating reagent in supercritical CO(2).

4,4'-Bis(dihexylaminocarbonyl)-2,2'-bipyridine (BDC-Bipy) was synthesized and studied systematically as a chelating reagent for metal ions extraction in supercritical CO(2). The compound showed high extraction efficiency for Co(2+) (100%), Cu(2+) (100%), Cd(2+) (98.2%), and Zn(2+) (100%) ions and good extraction efficiency for Sr(2+) (79.4%) and Pb(2+) (89.8%) when the extraction was performed in supercritical CO(2) at 313 K and 25 MPa with the system of BDC-Bipy, deionized water and perfluoro-1-octanesulfonic acid tetraethylammonium salt. The recoveries of mixed metal ions were also measured; unfortunately, the system of extraction has no selectivity for the metal ions.

Journal Article↗

[Distribution features of Gleason score and its relationship with clinical stages in 346 prostate cancer patients].

OBJECTIVE: To analyze the distribution features of Gleason score and evaluate the relationship between Gleason score and clinical stages in patients with prostate cancer. METHODS: Surveys were made of the inpatients with prostate cancer diagnosed by pathology from January 1992 to June 2005 in our hospital. Gleason score and clinical stages were determined on the basis of pathological examination and clinical data of the prostate cancer patients. The patients were divided into three groups (1992-1999, 2000-2002 and 2003-2005). The Chi-square test was used to evaluate the distribution and differences of Gleason score among the three groups. Spearman rank correlation was applied to the evaluation of the relationship between Gleason score and clinical stages. RESULTS: We found a statistically significant shift in the distribution of Gleason score (chi2 = 17.703, P < 0.01), and a slight increase in the mean Gleason score. The proportion of moderately differentiated tumor increased (chi2 = 10.736, P < 0.01). There was little change in the proportion of Gleason score 7, 8, 9 and 10 (chi2 = 4.038, P > 0.05). Gleason score had a significant positive correlation with clinical stages in the 346 cases of prostate cancer (r = 0.452, P < 0.01). Significant difference was observed between Gleason score 2-6 and 7 or 8-10 (chi2 = 8.786, P < 0.01, chi2 = 22.956, P < 0.01), but not between the latter 2 groups (chi2 = 0.787, P > 0.05) in prediction of organ-confined disease. CONCLUSIONS: Gleason score 7 shows the similar value to Gleason score 8-10 in predicting the progression of the disease. Gleason score was significantly correlated with clinical stages, which suggests that Gleason score is also an important indicator for the prognosis of prostate cancer.

Adult↗

Determining the Mg2+ stoichiometry for folding an RNA metal ion core.

The folding and catalytic function of RNA molecules depend on their interactions with divalent metal ions, such as magnesium. As with every molecular process, the most basic knowledge required for understanding the close relationship of an RNA with its metal ions is the stoichiometry of the interaction. Unfortunately, inventories of the numbers of divalent ions associated with unfolded and folded RNA states have been unattainable. A common approach has been to interpret Hill coefficients fit to folding equilibria as the number of metal ions bound upon folding. However, this approach is vitiated by the presence of diffusely associated divalent ions in a dynamic ion atmosphere and by the likelihood of multiple transitions along a folding pathway. We demonstrate that the use of molar concentrations of background monovalent salt can alleviate these complications. These simplifying solution conditions allow a precise determination of the stoichiometry of the magnesium ions involved in folding the metal ion core of the P4-P6 domain of the Tetrahymena group I ribozyme. Hill analysis of hydroxyl radical footprinting data suggests that the P4-P6 RNA core folds cooperatively upon the association of two metal ions. This unexpectedly small stoichiometry is strongly supported by counting magnesium ions associated with the P4-P6 RNA via fluorescence titration and atomic emission spectroscopy. By pinpointing the metal ion stoichiometry, these measurements provide a critical but previously missing step in the thermodynamic dissection of the coupling between metal ion binding and RNA folding.

Catalysis↗

Amperometric nitrite sensor based on hemoglobin/colloidal gold nanoparticles immobilized on a glassy carbon electrode by a titania sol-gel film.

A novel amperometric nitrite sensor was developed based on the immobilization of hemoglobin/colloidal gold nanoparticles on a glassy carbon electrode by a titania sol-gel film. The sensor shows a pair of well-defined and nearly reversible cyclic voltammogram peaks for Hb Fe(III)/Fe(II) with a formal potential (E degrees ') of -0.370 V, and the peak-to-peak separation at 100 mV s(-1) was 66 mV vs. Ag/AgCl (3.0 M KCl) in a pH 6.9 phosphate buffer solution. The formal potential of the Hb Fe(III)/Fe(II) couple shifted linearly with pH with a slope of -50.0 mV/pH, indicating that electron transfer accompanies single-proton transportation. The sensor exhibited an excellent electrocatalytic response to the reduction of nitrite. The reduction overpotential was 0.45 V below that obtained at a colloidal gold nanoparticles/TiO2 sol-gel film-modified GCE. The linear range for nitrite determination for the sensor was 4.0 x 10(-6) to 3.5 x 10(-4) M, with a detection limit of 1.2 x 10(-6) M. The stability, repeatability and selectivity of the sensor were also evaluated.

Carbon↗

Probing counterion modulated repulsion and attraction between nucleic acid duplexes in solution.

Understanding biological and physical processes involving nucleic acids, such as the binding of proteins to DNA and RNA, DNA condensation, and RNA folding, requires an understanding of the ion atmosphere that surrounds nucleic acids. We have used a simple model DNA system to determine how the ion atmosphere modulates interactions between duplexes in the absence of specific metal ion-binding sites and other complicated interactions. In particular, we have tested whether the Coulomb repulsion between nucleic acids can be reversed by counterions to give a net attraction, as has been proposed recently for the rapid collapse observed early in RNA folding. The conformation of two DNA duplexes tethered by a flexible neutral linker was determined in the presence of a series of cations by small angle x-ray scattering. The small angle x-ray scattering profiles of two control molecules with distinct shapes (a continuous duplex and a mimic of the compact DNA) were in good agreement with predictions, establishing the applicability of this approach. Under low-salt conditions (20 mM Na+), the tethered duplexes are extended because of a Coulombic repulsion estimated to be 2-5 kT/bp. Addition of high concentrations of Na+ (1.2 M), Mg2+ (0.6 M), and spermidine3+ (75 mM) resulted in electrostatic relaxation to a random state. These results indicate that a counterion-induced attractive force between nucleic acid duplexes is not significant under physiological conditions. An upper limit on the magnitude of the attractive potential under all tested ionic conditions is estimated.

DNA↗

Biomass and microbial activity in a biofilter during backwashing.

Biomass and microbial activity in backwashing processes of a biofilter for tertiary treatment were investigated. The microbial groups revealed new distribution along the biofilter depth after low flow rate backwashing for a short time. Then the start-up process was accelerated by backwashing. The biomass profile and microbial activity profile both varying with depth before and after backwashing, can be mathematically described by quadratic equations. Using the profiles, the difference of oxygen demand can be calculated to determine the airflow rate during backwashing. Combined with the difference between biofilters and rapid gravity filters, analysis of biomass and microbial activity can determine more accurately the required airflow rate during backwashing.

Biomass↗

[Influence of the mutants of hepatitis B surface antigen on the cell immunity].

OBJECTIVE: To study the influence of the mutants of hepatitis B surface antigen on the cell immunity. METHODS: The recombinant plasmids of NS2Swt, NS2S126, NS2S133, NS2S141 and NS2S145 were transfected into Chinese hamster ovary (CHO) cells and the expressed proteins were detected by means of ELISA. Following PHA-activated lymphoblasts proliferation assay and IFN-gamma, IL-2, IL-10 induction assay were done with these proteins. RESULTS: It was identified that these proteins of HBsAg could stimulate human lymphoblasts proliferation. Besides, there were no significant difference between the mutants and the wild. It was deserved to point out that the HBsAg with T126S mutation could increase the expression of IFN-gamma in the culture medium while the HBsAg with M133T mutation induced more expression of IL-10. CONCLUSION: The results suggested that the cellular immune response to mutants of HBV might not be strengthened or weakened. But it should not be ignored that HBV T126S or M133T mutation may assert a potential impact on the cell immunity.

Animals↗

[Apoptosis of human oral epidermoid carcinoma KB cells and multidrug resistant KBv200 cells induced by matrine].

OBJECTIVE: To investigate the induction of apoptosis on human oral epidermoid carcinoma KB cells and multidrug resistant KBv200 cells by Matrine. METHODS: MTT assay was used to investigate the inhibition ability of Matrine on the cells in vitro. Transmission electron microscope was used to observe the ultrastructure feature of cells. after treated by Matrine. Acridine orange (AO)/Ethidium bromide (EB) fluorescent staining and flow cytometry were used to observe apoptosis induced by Matrine. Flow cytometry was applied to study the effects of the drug on cell cycles of the cells. RESULTS: When 0.50, 1.00, 1.50, 2.00 mg/ml of Matrine was used, the vital rates of KB and KBv200 cells were decreased according to Matrine's concentration. The IC50 concentrations of Matrine on KB and KBv200 cells were 1.35 mg/ml and 1.43 mg/ml individually. The results of AO/EB fluorescent staining and flow cytometry showed that Matrine could induce apoptosis of two kinds of cells. While observed by transmission electron microscope, there were more contraction of cells, condensation of nuclei, bubble of cytoplasm in both kinds of cells after treated by Matrine. Matrine could stop the growth of KB and KBv200 cells at S period and restrain mitosis of cells. CONCLUSION: Matrine can inhibit the growth of KB and KBv200 cells by inducing apoptosis. The apoptosis effect is dose-dependent and it has certain relation to the blocking of S period cells.

Alkaloids↗