Biomedical subjects

Hanqi Zhang

Publications and source records attributed to Hanqi Zhang.

At least 19 recordsLinked to original sources

PubMed2026

Molecular epidemiology and genomic characteristics of clinical Acinetobacter baumannii isolates from patients with hospital-acquired pneumonia in China, 2019-2020: a multicentre retrospective study.

BACKGROUND: Carbapenem-resistant Acinetobacter baumannii (CRAB) is a leading cause of hospital-acquired pneumonia (HAP) with high mortality. However, large-scale nationwide data of HAP-causing CRAB in China remain limited. METHODS: Here, we performed a nationwide multicentre retrospective study to characterise the molecular epidemiology and genomic features of 802 A. baumannii isolates from patients with HAP across 33 tertiary hospitals in China during 2019-2020. Antimicrobial susceptibility testing (AST), whole-genome sequencing (WGS), phylogenetic and comparative genomic analysis were used to investigate molecular epidemiology of HAP-causing CRAB strain. Clinical comparative analyses were carried out on data from 500 patients with HAP stratified by distinct antimicrobial susceptibility and genomic profiles, and a Galleria mellonella infection model was utilised for in vivo virulence assessment. FINDINGS: The overall carbapenem resistance rate of A. baumannii was 82.0% (658/802), with marked regional variations. CRAB exhibited high resistance to conventional agents but remained largely susceptible to polymyxin, tigecycline, cefiderocol and sulbactam-durlobactam. Among enrolled patients, CRAB infection was linked to substantially higher mortality (39.0% vs. 17.5%), and multivariate analysis confirmed ICU admission and advanced age as independent risk factors for patients with CRAB infection. Molecular typing revealed STPas2 (96.2%) as the absolutely predominant type; STOxf208, STOxf195, STOxf540, and STOxf369 were the most prevalent Oxford sequence types with obvious geographic stratification and divergent comorbidity profiles among corresponding patients. A total of 654 CRAB isolates harboured carbapenemase genes, with blaOXA-23 dominating at 98.8%. Genomic analysis revealed lineage-specific features: STOxf208 carried more virulence genes, while STOxf540 harboured a broader antimicrobial resistance genes (ARGs). The STOxf208 clone mainly belonged to KL2 (62.1%) and KL7 (36.8%) serotypes, with KL2 strains possessing richer ARGs and virulence factors, and in vivo virulence assays further validated that KL2 strains possessed higher pathogenicity than KL7 strains. INTERPRETATION: This study demonstrates the extremely high prevalence and clonal dominance of CRAB in Chinese patients with HAP, providing critical evidence for clinical treatment, antimicrobial stewardship, and targeted infection control. FUNDING: National Key Research and Development Program of China (2024YFE0106200), National Natural Science Foundation of China (U22A20338, 82502763, W2621007), Zhejiang Provincial Natural Science Foundation of China (LQN25H190006), Zhejiang Provincial Postdoctoral Science Foundation (ZJ2025058).

Acinetobacter baumannii↗

PubMed2007

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↗

PubMed2006

On-line coupling of dynamic microwave-assisted extraction with high-performance liquid chromatography for determination of andrographolide and dehydroandrographolide in Andrographis paniculata Nees.

A novel technique based on dynamic microwave-assisted extraction (DMAE) coupled on-line with high-performance liquid chromatography (HPLC) through a flow injection interface has been developed for determination of andrographolide and dehydroandrographolide in Andrographis paniculata Nees. A TM(010) microwave resonance cavity built in the laboratory was applied to concentrating the microwave energy. An extraction vessel was placed in microwave irradiation zone. The extraction was performed in a recirculating system. When a number of extraction cycles were completed, the fractional extract (20muL) was driven to the analytical column by 65% aqueous methanol and was measured by diode array detector (DAD) at 225nm. The optimized extraction conditions are follows: extraction solvent 60% aqueous methanol; microwave forward power 80W; extraction time 6min; extraction solvent flow-rate 1.0mLmin(-1). The detection and quantification limits obtained are 0.5 and 1.7microgmL(-1) for andrographolide and 0.6 and 1.9microgmL(-1) for dehydroandrographolide, respectively. The within-day and between-day precision (RSD) are 2.1% and 3.7% for andrographolide and 1.7% and 4.1% for dehydroandrographolide, respectively. Mean recoveries for andrographolide and dehydroandrographolide are 97.7% and 98.7%, respectively. Compared with ultrasonic extraction used in the Chinese pharmacopoeia, the proposed method was demonstrated to obtain higher extraction yield in a shorter time. In addition, only small quantities of solvent (5mL) and sample (10mg) were required.

Andrographis↗

PubMed2006

Resonance light scattering technique for the determination of proteins with polymethacrylic acid (PMAA).

As a resonance light scattering (RLS) probe, the polyelectrolyte polymethacrylic acid (PMAA) was applied in this assay. The bovine serum albumin (BSA) and human serum albumin (HSA) were determined by the electrostatic interaction of PMAA and proteins. At pH 3.8 Na(2)HPO(4)-citric acid buffer solution, the RLS intensities of PMAA-BSA (HSA) system were greatly enhanced. The characteristic peaks were appeared at the wavelength 320, 546 and 594 nm. The optimization conditions of the reaction were also examined and selected. Under the selected conditions, the RLS intensities were proportional to the protein concentrations in the range of (0.0200-2.00) x 10(-6) mol/L for BSA and (0.0200-2.40) x 10(-6) mol/L for HSA. The influences of some foreign substances were also examined. The synthetic samples containing proteins and some real samples were analyzed and the results obtained were satisfactory.

Animals↗

PubMed2006

Rapid analysis of the essential oils from dried Illicium verum Hook. f. and Zingiber officinale Rosc. by improved solvent-free microwave extraction with three types of microwave-absorption medium.

A new method of extracting essential oils from dried plant materials has been studied. By adding a microwave-absorption medium (MAM) to a reactor, solvent-free microwave extraction (SFME) was improved and can be used to extract essential oils from dried plant material without pretreatment. With a microwave irradiation power of 85 W it took only approximately 30 min to extract the essential oils completely. The whole extraction process is simple, rapid, and economical. Three types of MAM, iron carbonyl powder (ICP), graphite powder (GP), and activated carbon powder (ACP), and two types of dried plant material, Illicium verum Hook. f. and Zingiber officinale Rosc., were studied. The results were compared with those obtained by use of conventional SFME, microwave-assisted hydrodistillation (MAHD), and conventional hydrodistillation (HD), and the conclusion drawn was that improved SFME was a feasible means of extracting essential oils from dried plant materials, because there were few differences between the composition of the essential oils extracted by improved SFME and by the other methods.

Adsorption↗

PubMed2006

Analysis of ultraviolet absorption spectrum of Chinese herbal medicine-Cortex Fraxini by double ANN.

A fast, accurate and convenient method for the simultaneous determination of multi-component in the Chinese herbal medicine was proposed by using ultraviolet absorption spectrum. In this method, dummy components were added to training sample, and a double artificial neural network (DANN) that has the function of high self-revision and self-simulation was used. Effect of other interference components could be eliminated by adjusting concentration of dummy components. Therefore, the accuracy of concentration prediction for multi-component in the complicated Chinese herbal medicine was improved. It has been realized that two effective components of Cortex Fraxini, aesculin and aesculetin, were simultaneously determined, without any separation. The predicted accuracy was 92% within the permitted relative errors. The measurement precisions of the aesculin and aesculetin were 0.37% and 1.5%, respectively.

Absorption↗

PubMed2006

Development of an analytical method for organotin compounds in fortified flour samples using microwave-assisted extraction and normal-phase HPLC with UV detection.

The normal high-performance liquid chromatography with UV detection was applied for the determination of tributyltin chloride (TBT), triphenyltin chloride (TPhT), tetraphenyltin (TrPhT), triethyltin chloride (TET) and tetraethyltin (TrET) from flour samples. The separation was performed in the isocratic mode on cyanopropyl column with a mobile phase of hexane-acetonitrile-THF (97/1/2). Under the experimental conditions used, quantitative limit of TBT, TPhT, TrPhT, TET and TrET are 0.95, 0.46, 0.97, 0.75 and 0.96 microg/ml, respectively. Microwave-assisted extraction of organotin (OT) compounds at 100 degrees C with an extraction time of 3 min was described. The extraction of organotin can be finished in acetic acid-hexane (20/80) medium. The quantitative extraction of five organotin compounds was achieved with recoveries ranging from 88 to 101% R.S.D. 3-8%.

Analytic Sample Preparation Methods↗

PubMed2006

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↗

PubMed2006

Investigation on hyperin-cetyltrimethylammonium bromide-fibronectin system by resonance light-scattering technique.

A simple, highly sensitive assay for fibronectin (Fn) was reported using resonance light-scattering (RLS) technique based on the enhanced RLS intensity of hyperin-cetyltrimethylammonium bromide (CTMAB)-Fn system. The interaction system of hyperin-CTMAB-Fn was investigated using spectral methods. Mechanistic investigations show that the main reason of the enhanced RLS intensity of Fn is the formation of three-component complex (hyperin-CTMAB-Fn), in which CTMAB acts as a bridge between hyperin and Fn. The effects of pH, surfactant, concentration of CTMAB and hyperin, incubation time and foreign substances on the enhancement of RLS intensity were studied. Under the optimum conditions, the enhancement of RLS intensity is in proportion to the concentration of Fn in the range of 1.9-248ng/ml. The synthetic samples containing Fn were analyzed and results obtained were satisfied.

Cetrimonium↗

PubMed2006

Investigation on the interaction between colloidal gold and human complement factor 4 at different pH by spectral methods.

The interaction between colloidal gold and human complement factor 4 (human C4) at different pH was investigated by spectral methods, including absorption and resonance light-scattering spectrometry. According to the changes of color and absorption spectra of colloidal gold solution in presence of human C4, the interaction between colloidal gold and human C4 was quantitatively investigated using a semi-empirical "flocculation parameter". At the same time, the changes of resonance light-scattering spectra and transmission electron microscopy (TEM) images indicate that the aggregation of colloidal gold happens by electrostatic interaction in presence of human C4 in the pH range 5-6. However, the colloidal gold solution remains stable at pH >6 and pH <5 due to the repulsive electrostatic interaction between colloidal gold and human C4. The flocculation parameter is directly proportional to the concentration of human C4 in the range from 9.7 to 233.0 microgl(-1). In addition, the interactions between the colloidal gold and bovine serum albumin (BSA) as well as human serum albumin (HSA) were also investigated using the same methods. It was found that there was no aggregation of colloidal gold in presence of BSA and HSA in the pH range 5-6. However, when the pH of solution is 4, the aggregation of colloidal gold happens. Because BSA and HSA have different structure, the intensity of aggregation of colloidal gold in presence of BSA is greater than that in presence of HSA at pH 4.

Animals↗

PubMed2005

Determination of human complement factor C4 using resonance light-scattering technique with sodium dodecylbenzene sulphonate probe.

Based on the interaction between human complement factor C4 (human C4) and sodium dodecylbenzene sulphonate (SDBS) and the resonance light-scattering (RLS) technique, a highly sensitive assay for human C4 using resonance light-scattering technique was developed. At pH 2.8 Na2HPO4-citric acid buffer solution, the RLS intensities of SDBS system at 283, 503 and 600 nm were obviously enhanced in the presence of human C4. The effects of surfactant, pH, incubation time, concentration of SDBS and foreign substances on the enhanced RLS intensity of system were investigated. Under the optimum conditions, the enhanced RLS intensity is directly proportional to the concentration of human C4 in the range of (0.5-120)x10(-6)gl-1 and the linear regression equation was obtained with high correlation coefficient. This RLS technique was applied to the determination of human C4 in some synthetic samples with good recovery. Moreover, it was found that the electrostatic interaction is the main binding force between SDBS and human C4.

Benzenesulfonates↗

PubMed2005

Improved solvent-free microwave extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim.

Solvent-free microwave extraction (SFME) is a recently developed green technique which is performed in atmospheric conditions without adding any solvent or water. SFME has already been applied to extraction of essential oil from fresh plant materials or dried materials prior moistened. The essential oil is evaporated by the in situ water in the plant materials. In this paper, it was observed that an improved SFME, in which a kind of microwave absorption solid medium, such as carbonyl iron powders (CIP), was added and mixed with the sample, can be applied to extraction of essential oil from the dried plant materials without any pretreatment. Because the microwave absorption capacity of CIP is much better than that of water, the extraction time while using the improved SFME is no more than 30 min using a microwave power of 85 W. Compared to the conventional SFME, the advantages of improved SFME were to speed up the extraction rate and need no pretreatment. Improved SFME has been compared with conventional SFME, microwave-assisted hydrodistillation (MAHD) and conventional hydrodistillation (HD) for the extraction of essential oil from dried Cuminum cyminum L. and Zanthoxylum bungeanum Maxim. By using GC-MS system the compositions of essential oil extracted by applying four kinds of extraction methods were identified. There was no obvious difference in the quality of essential oils obtained by the four kinds of extraction methods.

Chromatography, Liquid↗

PubMed2005

Studies on the interaction of colloidal gold and serum albumins by spectral methods.

The interactions of colloidal gold and serum albumins, including bovine serum albumin (BSA) and human serum albumin (HSA), were studied by fluorescence and absorption spectrometry. Fluorescence quenching spectrometry was applied to study the interactions between colloidal gold and serum albumins. At pH 7.4 phosphate-buffered saline (PBS), the intensity of fluorescence emission spectrum of serum albumins decreased in the presence of colloidal gold, which indicated that colloidal gold quenched the fluorescence of serum albumins. Experimental results indicated that the combination reactions of colloidal gold and serum albumins were static quenching processes. Based on the effect of colloidal gold on fluorescence intensity, the binding constants, the numbers of binding sites and the acting forces between colloidal gold and serum albumins were found.

Animals↗

PubMed2005

Molecular spectroscopic study on the interaction of tetracyclines with serum albumins.

A molecular spectroscopic investigation of the interaction between tetracyclines antibiotics and human serum albumin or bovine serum albumin was reported. The influences of some metal ions on the interaction were also studied. When tetracyclines drugs were added into the solution containing serum albumins, the fluorescence intensity of serum albumins decreased with the increasing of the drugs concentrations, which is due to the formation of new non-fluorescence complexes of drug-serum albumin. The tetracyclines acted as quenchers and quenched the fluorescence of the serum albumins. The binding constants and the number of the binding sites of the reaction of tetracyclines and serum albumins were obtained. The main sorts of acting force between the drugs and serum albumins were found and the action distances and the energy transfer efficiencies between donor-acceptor were calculated based on the Foster energy transference.

Animals↗

PubMed2005

Spectroscopic characterization of effective components anthraquinones in Chinese medicinal herbs binding with serum albumins.

The interactions of serum albumins such as human serum albumin (HSA) and bovine serum albumin (BSA) with emodin, rhein, aloe-emodin and aloin were assessed employing fluorescence quenching and absorption spectroscopic techniques. The results obtained revealed that there are relatively strong binding affinity for the four anthraquinones with HSA and BSA and the binding constants for the interactions of anthraquinones with HSA or BSA at 20 degrees C were obtained. Anthraquinone-albumin interactions were studied at different temperatures and in the presence of some metal ions. And the competition binding of anthraquinones with serum albumins was also discussed. The Stern-Volmer curves suggested that the quenching occurring in the reactions was the static quenching process. The binding distances and transfer efficiencies for each binding reactions were calculated according to the Föster theory of non-radiation energy transfer. Using thermodynamic equations, the main action forces of these reactions were also obtained. The reasons of the different binding affinities for different anthraquinone-albumin reactions were probed from the point of view of molecular structures.

Anthraquinones↗

PubMed2004

Sensitivity-enhancement of wavelength-modulation surface plasmon resonance biosensor for human complement factor 4.

Sandwich and colloidal Au techniques for enhancing the sensitivity of a wavelength-modulation surface plasmon resonance (SPR) immunosensor are demonstrated by the detection of human complement factor 4 (C4). The design of the wavelength-modulation SPR biosensor is based on fixing the incident angle of light and measuring the reflected intensity of light in the wavelength range spanning 500-900 nm simultaneously. The human C4 had good response in the concentration range 2-20 microg/mL in the direct assay. However, in the sandwich assay, the human C4 had good response in the concentration range 0.2-20 microg/mL and the lowest concentration is 10-fold lower than that obtained by the direct assay. With human C4-Au colloidal conjugate, the human C4 had good response in the concentration range 0.1-20 microg/mL and the lowest concentration is 20-fold lower than that obtained by the direct assay. In the colloidal-Au-enhanced sandwich assay, the human C4 had good response in the concentration range 0.05-5 microg/mL and the lowest concentration is 40-fold lower than that obtained by the direct assay. Under selected experimental conditions, the reproducibility, sensitivity, and reversibility of the enhanced SPR immunoassay are very satisfactory. The results represent potentially significant advantages in the sensitivity of SPR biosensors.

Antibodies↗

PubMed2003

A novel sandwich immunosensing method for measuring cardiac troponin I in sera.

Common methods for monitoring human cardiac troponin I (cTn I) are based on using antibodies against cTn I labeled with horseradish peroxidase, radioactive isotopes, or other labels. In this study, a novel label-free sandwich immunosensing method for measuring cTn I was developed. Three monoclonal antibodies (mAbs 9F5, 2F11, and 8C12) against human cTn I were generated by the commonly used hybridoma technique and characterized by a surface plasmon resonance (SPR) biosensor. An optimal pair of mAbs for measuring human cTn I was selected, as both mAbs have high affinities for cTn I and do not compete against each other for cTn I binding. An optical immunosensor for measuring cTn I in sera based on SPR was developed by using avidin as an intermediate layer and biotinylated-2F11 as the capturing antibody. Two detection methods for cTn I with the immunosensor were performed: (1) the direct detection of cTn I with a detection range of 2.5 to 40 microg/L and (2) the sandwich immunosensing method. In the sandwich assay mode, the second antibody 9F5 biologically amplified the sensor response. As a result, the sandwich assay showed a sensitivity of 0.25 microg/L and a detection range of 0.5 to 20 microg/L with within-run variation of 4.9 to 6.7% and between-run variation of 5.2 to 8.4%. This method has greatly enhanced the sensitivity for detection compared to that previously reported in the literatures.

Antibodies, Monoclonal↗

PubMed2003

MECC determination of oleanolic acid and ursolic acid isomers in Ligustrum lucidum Ait.

In this paper, a novel method to separate and determine oleanolic acid and ursolic acid isomers in Ligustrum lucidum Ait was studied by micellar electrokinetic capillary chromatography (MECC). The baseline separation of the two analytes were obtained on the condition that the buffer contained 15 mmol/l disodium hydrogen phosphate, 15 mmol/l disodium tetreborate, 10 mmol/l SDS and 5% (v/v) alcohol. The contents of the oleanolic acid and ursolic acid were determined in L. lucidum Ait, Folium photiniae and Flos campsis; they were 78.3 (R.S.D. = 2.75%) and 20.7 mg/g (R.S.D. = 2.97%), 27.9 (R.S.D. = 3.67%) and 79.8 mg/g (R.S.D. = 3.44%), 65.5 (R.S.D. = 3.73%) and 60.4 mg/g (R.S.D. = 4.06%) (n = 5), respectively. The recoveries of the analytes in the extract of L. lucidum Ait were 102%, (R.S.D. = 2.85%) for oleanolic acid and 104% (R.S.D. = 3.21%) for ursolic acid (n = 5). With the emphasis on the effects of SDS and alcohol concentrations on the separation of the isomers were investigated.

Algorithms↗