Enhanced dewaterability and triclosan removal of waste activated sludge with iron-rich mineral-activated peroxymonosulfate.

High water and pharmaceutical and care products (PPCPs) bounded in sludge flocs limit its utilization and disposal. The advanced oxidation process of perxymonosulfate (PMS) catalyzed by iron salts has been widely used in sludge conditioning. In this study, two iron-rich minerals pyrite and siderite were proposed to enhance sludge dewatering performance and remove the target contaminant of triclosan (TCS). The permanent release of Fe2+ in the activation of PMS made siderite more effective in enhancing sludge dewater with capillary suction time (CST) diminishing by 60.5 %, specific resistance to filtration (SRF) decreasing by 79.2 %, and bound water content (BWC) dropping from 37.1 % to 2.6 % at siderite/PMS dosages of 0.36/0.20 mmol/g-TSS after 20 min of pretreatment. Pyrite/PMS performed slightly inferior under the same conditions and the corresponding CST and SRF decreased by 51.5 % and 71.8 % while the BWC only declined to 17.8 %. Rheological characterization was employed to elucidate the changes in sludge dewatering performance, with siderite/PMS treated sludge showing a 48.3 % reduction in thixotropy, higher than 28.4 % of pyrite/PMS. Oscillation and creep tests further demonstrated the significantly weakened viscoelastic behavior of the sludge by siderite/PMS pretreatment. For TCS mineralization removal, siderite/PMS achieved a high removal efficiency of 43.9 %, in comparison with 39.9 % for pyrite/PMS. The reduction in the sludge solids phase contributed the most to the TCS removal. Free radical quenching assays and EPR spectroscopy showed that both siderite/PMS and pyrite/PMS produced SO4-·  and ·OH, with the latter acting as the major radicals. Besides, the dosage of free radicals generated from siderite/PMS exhibited a lower time-dependence, which also allowed it to outperform in destroying EPS matrix, neutralizing the negative Zeta potential of sludge flocs, and mineralizing macromolecular organic matter.

Biogas upgrading and membrane anti-fouling mechanisms in electrochemical anaerobic membrane bioreactor (EC-AnMBR): Focusing on spatio-temporal distribution of metabolic functionality of microorganisms.

Electrochemical anaerobic membrane bioreactor (EC-AnMBR) by integrating a composite anodic membrane (CAM), represents an effective method for promoting methanogenic performance and mitigating membrane fouling. However, the development and formation of electroactive biofilm on CAM, and the spatio-temporal distribution of key functional microorganisms, especially the degradation mechanism of organic pollutants in metabolic pathways were not well documented. In this work, two AnMBR systems (EC-AnMBR and traditional AnMBR) were constructed and operated to identify the role of CAM in metabolic pathway on biogas upgrading and mitigation of membrane fouling. The methane yield of EC-AnMBR at HRT of 20 days was 217.1 ± 25.6 mL-CH4/g COD, about 32.1 % higher compared to the traditional AnMBR. The 16S rRNA analysis revealed that the EC-AnMBR significantly promoted the growth of hydrolysis bacteria (Lactobacillus and SJA-15) and methanogenic archaea (Methanosaeta and Methanobacterium). Metagenomic analysis revealed that the EC-AnMBR promotes the upregulation of functional genes involved in carbohydrate metabolism (gap and kor) and methane metabolism (mtr, mcr, and hdr), improving the degradation of soluble microbial products (SMPs)/extracellular polymeric substances (EPS) on the CAM and enhancing the methanogens activity on the cathode. Moreover, CAM biofilm exhibits heterogeneity in the degradation of organic pollutants along its vertical depth. The bacteria with high hydrolyzing ability accumulated in the upper part, driving the feedstock degradation for higher starch, sucrose and galactose metabolism. A three-dimensional mesh-like cake structure with larger pores was formed as a biofilter in the middle and lower part of CAM, where the electroactive Geobacter sulfurreducens had high capabilities to directly store and transfer electrons for the degradation of organic pollutants. This outcome will further contribute to the comprehension of the metabolic mechanisms of CAM module on membrane fouling control and organic solid waste treatment and disposal.

Performance of Large Area n-TOPCon Solar Cells with Selective Poly-Si Based Passivating Contacts Prepared by PECVD Method.

Selective emitter (SE) technology significantly influences the passivation and contact properties of n-TOPCon solar cells. In this study, three mask layers (SiOx, SiNx, and SiOxNy) were employed to fabricate n-TOPCon solar cells with phosphorus (P)-SE structures on the rear side using a three-step method. Additionally, phosphosilicon glass (PSG) was used to prepare n-TOPCon solar cells with P-SE structure on the rear side using four-step method, and the comparative analysis of electrical properties were studied. The SiOx mask with a laser power of 20 W (O2 group) achieved the highest solar cell efficiency (Eff, 24.85%), The open-circuit voltage (Voc) is 2.4 mV higher than that of the H1 group, and the fill factor (FF) is 1.88% higher than that of the L1 group. Furthermore, the final Eff of solar cell is 0.17% higher than that of the L1 group and 0.20% higher than that of the H1 group. In contrast, using the four-step method and a laser power of 20 W (P2 group), a maximum Eff of 24.82% was achieved. Moreover, it exhibited an Voc, which is elevated by 3.2 mV compared to the H1 group, and FF increased by 1.49% compared to the L1 group. Furthermore, the overall Eff of the P2 group outperforms both the L1 and H1 groups by approximately 0.14% and 0.17%, respectively. In the four-step groups, the Eff of each laser condition group was improved compared with the L1 group and H1 group, The stability observed within the four-step method surpassed that of the three-step groups. However, in terms of full-scale electrical properties, the three-step method can achieve comparable results as those obtained from the four-step method. This research holds significant guiding implications for upgrading the n-TOPCon solar cell rear-side technology during mass production.

Simultaneous removal of antibiotic resistance genes and improved dewatering ability of waste activated sludge by Fe(II)-activated persulfate oxidation.

Waste activated sludge properties vary widely with different regions due to the difference in living standards and geographical distribution, making a big challenge to developing a universally effective sludge dewatering technique. The Fe(II)-activated persulfate (S2O82-) oxidation process shows excellent ability to disrupt sludge cells and extracellular polymeric substances (EPS), and release bound water from sludge flocs. In this study, the discrepancies in the physicochemical characteristics of sludge samples from seven representative cities in China (e.g., dewaterability, EPS composition, surface charge, microbial community, relative abundance of antibiotic resistance genes (ARGs), etc.) were investigated, and the role of Fe(II)-S2O82- oxidation in enhancing removal of antibiotic resistance genes and dewatering ability were explored. The results showed significant differences between the EPS distribution and chemical composition of sludge samples due to different treatment processes, effluent sources, and regions. The Fe(II)-S2O82- oxidation pretreatment had a good enhancement of sludge dewatering capacity (up to 76 %). Microbial analysis showed that the microbial community in each sludge varied significantly depending on the types of wastewater, the wastewater treatment processes, and the regions, but Fe(II)-S2O82- oxidation was able to attack and rupture the sludge zoogloea indiscriminately. Genetic analysis further showed that a considerable number of ARGs were detected in all of these sludge samples and that Fe(II)-S2O82- oxidation was effective in removing ARGs by higher than 90 %. The highly active radicals (e.g., SO4-·, ·OH) produced in this process caused drastic damage to sludge microbial cells and DNA stability while liberating the EPS/cell-bound water. Co-occurrence network analysis highlighted a positive correlation between population distribution and ARGs abundance, while variations in microbial communities were linked to regional differences in living standards and level of economic development. Despite these variations, the Fe(II)-S2O82- oxidation consistently achieved excellent performance in both ARGs removal and sludge dewatering. The significant modularity of associations between different microbial communities also confirms its ability to reduce horizontal gene transfer (HGT) by scavenging microbes.

An in-depth survey on Deep Learning-based Motor Imagery Electroencephalogram (EEG) classification.

Electroencephalogram (EEG)-based Brain-Computer Interfaces (BCIs) build a communication path between human brain and external devices. Among EEG-based BCI paradigms, the most commonly used one is motor imagery (MI). As a hot research topic, MI EEG-based BCI has largely contributed to medical fields and smart home industry. However, because of the low signal-to-noise ratio (SNR) and the non-stationary characteristic of EEG data, it is difficult to correctly classify different types of MI-EEG signals. Recently, the advances in Deep Learning (DL) significantly facilitate the development of MI EEG-based BCIs. In this paper, we provide a systematic survey of DL-based MI-EEG classification methods. Specifically, we first comprehensively discuss several important aspects of DL-based MI-EEG classification, covering input formulations, network architectures, public datasets, etc. Then, we summarize problems in model performance comparison and give guidelines to future studies for fair performance comparison. Next, we fairly evaluate the representative DL-based models using source code released by the authors and meticulously analyse the evaluation results. By performing ablation study on the network architecture, we found that (1) effective feature fusion is indispensable for multi-stream CNN-based models. (2) LSTM should be combined with spatial feature extraction techniques to obtain good classification performance. (3) the use of dropout contributes little to improving the model performance, and that (4) adding fully connected layers to the models significantly increases their parameters but it might not improve their performance. Finally, we raise several open issues in MI-EEG classification and provide possible future research directions.

Polyimide/crown ether composite film with low dielectric constant and low dielectric loss for high signal transmission.

Dielectric properties of polyimide (PI) are constrained by its inherent molecular structure and inter-chain packing capacities. The compromised dielectric properties of PI, however, could be rescued by introducing trifluoromethyl and forming a host-guest inclusion complex with the introduction of crown ethers (CEs). Herein, we report PI/crown ether composite films as a communication substrate that could be applied under high frequency circumstances. In this work, three kinds of bisphenol A-containing diamine (2,2'-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(2-methyl-4-aminophenoxy)phenyl]propane, and 2,2-bis[4-(2-trifluoro methyl-4-aminophenoxy)phenyl]propane) are synthesized and polymerized with 4,4'-(hexafluoroisopropylidene)diphthalic anhydride to prepare low-dielectric PI films by means of thermal imidization. Crown ethers are introduced into the PI with different mass fractions to obtain three series of PI films. Following the combination of trifluoromethyl into the molecular chain of PI, high frequency dielectric loss of modified PI films can be effectively reduced. The properties of these materials (especially the dielectric properties) are thoroughly explored by crown ether addition. The results show that the crown ether addition process can offer crown ethers with increased free volume of PI matrix, thus allowing them to generate a special necklace-like supramolecular structure, which makes the crown ether disperse more uniformly in the PI matrix, resulting in improved dielectric properties. Importantly, the dielectric constant and dielectric loss of the composite films at high frequencies are remarkably reduced to 2.33 and 0.00337, respectively. Therefore, these composite films are expected to find extensive use as a 5G communication substrate at high frequencies in the future.

Facilitating the Carrier Transport Kinetics at the CsPbBr3/Carbon Interface through SbX3 (X = Cl, Br, I) Passivation.

The nonradiative carrier recombination at the perovskite/carrier selective layer (CSL) interface was accounted for the inferior power conversion efficiency (PCE) of perovskite solar cells (PSCs), especially rigid all-inorganic perovskite (CsPbI3 and CsPbBr3). In this study, targeting the poor interface, we introduce SbX3 (X = Cl, Br, I) surface passivation at the CsPbBr3/carbon interface. Smoothed compressive strain, reduced defect density, and enhanced energy-level alignment were achieved simultaneously, facilitating carrier extraction at the selective interface. With the simple aqueous solution-based two-step process, the PCE of our SbI3 passivated carbon-based CsPbBr3 PSCs has increased from 7.81% (without passivation) to 9.69%, a ∼25% enhancement. Specifically, Voc (1.657 V) of the SbI3-passivated cells was much higher than that of the control ones (1.488 V), confirming the ameliorated interface. Finally, our unencapsulated SbI3 passivated devices maintain 90% of their initial PCEs while left in the air for 30 days with a relative humidity of 60%. To conclude, we present an interfacial carrier extraction-enhanced strategy for preparing high-performance and stable CsPbBr3-based PSCs.

Singlet Fission in Colloidal Nanoparticles of Amphipathic Diketopyrrolopyrrole Derivatives: Probing the Role of the Charge Transfer State.

To evaluate the role of the charge transfer (CT) state in the singlet fission (SF) process, we prepared three 3,6-bis(thiophen-2-yl)diketopyrrolopyrrole (TDPP) derivatives with zero (Ph2TDPP), one (Ph2TDPP-COOH), and two (Ph2TDPP-(COOH)2) carboxylic groups, respectively. Their colloidal nanoparticles were also prepared by a simple precipitation method. The SF dynamics and mechanism in these colloid nanoparticles were investigated by using steady-state/transient absorption and fluorescence spectroscopy. Steady-state absorption spectra reveal that the strength of the CT resonance interactions between the adjacent DPP units is increased gradually from Ph2TDPP to Ph2TDPP-COOH and then to Ph2TDPP-(COOH)2. Fluorescence and transient absorption spectra demonstrate that SF is proceeded via a CT-assisted superexchange mechanism in these three nanoparticles. Furthermore, SF rate and yield are enhanced gradually with the increase of the number of the carboxylic group, which may be attributed to the enhancement of the CT coupling strength. The result of this work not only provides a better understanding of the SF mechanism especially for the role of the CT state but also gives some new insights for the design of efficient SF materials based on DPP derivatives.

Effects of the Separation Distance between Two Triplet States Produced from Intramolecular Singlet Fission on the Two-Electron-Transfer Process.

To harvest two triplet excitons of singlet fission (SF) via a two-electron transfer efficiently, the revelation of the key factors that influence the two-electron-transfer process is necessary. Here, by using steady-state and transient absorption/fluorescence spectroscopy, we investigated the two-electron-transfer process from the two triplet excitons of intramolecular SF (iSF) in a series of tetracene oligomers (dimer, trimer, and tetramer) with 7,7,8,8-tetracyanoquinodimethane (TCNQ) as an electron acceptor in solution. Quantitative two-electron transfer could be conducted for the trimer and tetramer, and the rate for the tetramer is faster than that for the trimer. However, the maximum efficiency of the two-electron transfer in the dimer is relatively low (∼47%). The calculation result of the free energy change (ΔG) of the second-electron transfer for these three compounds (-0.024, -0.061, and -0.074 eV for the dimer, trimer, and tetramer, respectively) is consistent with the experimental observation. The much closer ΔG value to zero for the dimer should be responsible for its low efficiency of the two-electron transfer. Different ΔG values for these three oligomers are attributed to the different Coulomb repulsive energies between the two positive charges generated after the two-electron transfer that is caused by their various intertriplet distances. This result reveals for the first time the important effect of the Coulomb repulsive energy, which depends on the intertriplet distance, on the two-electron transfer process from the two triplet excitons of iSF.

Improved Perovskite/Carbon Interface through Hot-Pressing: A Case Study for CsPbBr3-Based Perovskite Solar Cells.

Due to the low cost and printable nature of the carbon paste, carbon-based perovskite solar cells (PSCs) are attractive for real application. However, the poor contact at the perovskite/carbon interface obviously hinders the achievable fill factor of the carbon-based PSCs. In this work, we introduce a pressure-assisted method to improve the contact at the perovskite/carbon interface. Via modulating the applied pressure, the power conversion efficiency of CsPbBr3 PSCs (small area) can be improved from the initial 7.40% to 7.95% (pressing) and 8.34% (hot-pressing). A more remarkable feature is that the hot-pressing process boosted the performance from 5.1% (normal) to 6.9% (hot-pressing assisted) of large-scale (0.5 cm2) devices, a more than 30% enhancement. Finally, the hot-pressing method introduced in this work shows great prospects for improving the efficiency of carbon-based PSCs, especially large-scale PSCs.

Embedding SnO2 Thin Shell Protected Ag Nanowires in SnO2 ETL to Enhance the Performance of Perovskite Solar Cells.

The energy level mismatching between SnO2 and perovskite and the nonradiative recombination at SnO2-perovskite interface severely degrade the extraction of carriers, reducing the power conversion efficiency (PCE) and stability of planar perovskite solar cells (PSCs) based on SnO2 electron transfer layer (ETL). In the present work, a reinforced SnO2 ETL was successfully developed by embedding SnO2 thin shell protected Ag nanowires (Ag/SnO2 NWs) in traditional planar SnO2 film, which was proved to not only lower the conduction band of SnO2 to adjust the energy level matching, but also significantly reduce the interfacial carrier recombination. Moreover, Ag/SnO2 NWs improved the electrical conductivity of SnO2 ETL, and effectively promoted carrier transport. Benefiting from the use of Ag/SnO2 NWs, our newly designed PSC achieved a significantly increased champion PCE of 19.78%, which is 7% higher than the traditional PSC without Ag/SnO2 NWs embedding, indicating its great application potential in PSCs.

Initial Clinical Characteristics of 146 Patients with COVID-19 Reported in Guizhou Province, China: A Survival Analysis.

INTRODUCTION: Coronavirus disease 2019 (COVID-19) has caused an outbreak around the world. Early detection of severe illness is crucial for patients' survival. We analysed initial clinical characteristics of 146 patients with COVID-19 reported in Guizhou province, China to explore risk factors for transforming mild illness to severe. METHODOLOGY: Data of 146 laboratory-confirmed cases were collected and evaluated by the survival analysis of univariate and multivariate Cox proportional hazards model. RESULTS: On initial presentation, patients had fever (51.05%), dry cough (45.45%), headache (16.08%), shortness of breath (7.75%) and gastrointestinal symptoms (13.99%). Among 146 laboratory-confirmed cases, 30 patients (20.55%) had severe illness and needed Intensive Care Unit care for supportive treatment. The remaining patients (116, 79.45%) were non-severe cases. Nineteen (19/146, 13.01%) of 30 patients in the Intensive Care Unit had comorbidities, including hypertension (12, 40.00%), diabetes (5, 16.67%), cardiovascular disease (5, 16.67%) and pulmonary disease (4, 13.33%). For survival analysis, patients who had fever (HR = 3.30, 95% CI = 1.31, 8.29) and comorbidities (HR = 9.76, 95% CI = 4.28, 22.23) at baseline were more likely to be admitted into the Intensive Care Unit. Few variables were not related to the survival time of discharge from baseline to discharge and from Intensive Care Unit care to discharge. CONCLUSIONS: Severe patients with COVID-19 should be paid more attention. On initial symptoms, many patients did not have fever, but those with fever were more likely to be admitted to the Intensive Care Unit. Comorbidities were likewise a risk factor of severe COVID-19.

Solubility, thermal and photoluminescence properties of triphenyl imidazole-containing polyimides.

In this paper, three kinds of triphenyl imidazole-containing diamines including 2-phenyl-4,5-bis(4-(4-amino-2-trifluoromethylphenoxy)phenyl)imidazole (PBAI), 2-(4-methylphenyl)-4,5-bis(4-(4-amino-2-trifluoromethyl phenoxy)phenyl)imidazole (MPBAI) and 2-(4-trifluoromethylphenyl)-4,5-bis(4-(4-amino-2-trifluoromethylphenoxy)phenyl)imidazole (TFPBAI) were synthesized. Then, a series of polyimide (PI) films were prepared by the solution polymerization of the three diamines and various dianhydrides, such as 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA), 1,2,4,5-pyromellitic dianhydride (PMDA) and 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA), followed by thermal imidization. The effects of chemical structures on the solubilities and thermal, optical and electrochemical properties of polyimides were explored. All the polyimides exhibited higher glass transition temperatures around 300 °C and excellent solubilities in common polar solvents. The polyimide films derived from CBDA or 6FDA showed better optical properties with light color and transparent characteristics. The fluorescence test showed that the photoluminescence color of CBDA-based polyimide films is in the blue range in the CIE 1931 spectrum, while the polyimide film based on PMDA and 6FDA presented black or weak yellow light. However, all these polyimides in solution exhibited similar blue luminescence. Electrochemical tests indicated that the HOMO and LUMO values of these films were around -6.5 and -3.6 eV, and the energy gap difference was about 3.0 eV. Therefore, the triphenyl imidazole-containing polyimides exhibit comprehensive performance, which will be expected as a new kind of functional material for certain application in the optical and optoelectronics fields.

Comparison of therapeutic effects of continuous epidural nerve block combined with drugs on postherpetic neuralgia.

PURPOSE: To compare the therapeutic effects of continuous epidural block combined with drugs and oral drugs alone on postherpetic neuralgia (PHN). METHODS: Ninety-six PHN patients meeting the standard were selected and divided into group A and group B. Patients in group A had epidural block combined with oral administration of gabapentin and oxycodone-acetaminophen, and patients in group B received oral gabapentin and oxycodone-acetaminophen. Visual analogue scale (VAS) and Wisconsin brief pain inventory scores were used to evaluate the patients in group A and group B for 6 times (before treatment, 1 d, 3 d, 7 d, 15 d and 30 d after treatment) respectively, and the complications and adverse reactions of the two treatment methods, as well as the number of cases requiring remedial measures were observed. RESULTS: There were significant differences in VAS and Wisconsin brief pain inventory scores at 1 d, 3 d, 7 d, 15 d and 30 d after treatment between the two groups (p < 0.05). Moreover, the scores before and after treatment decreased with the time of treatment, and there was a significant difference between the two groups at different time points (p < 0.05). No significant adverse reactions were observed in group A except for 1 patient with catheter detachment. Compared with group A, the adverse reactions of group B were more varied and obvious. CONCLUSION: Both treatments have certain effects on PHN, but epidural block combined with drug therapy is more effective, especially for patients with severe pain, early use can quickly relieve pain.

Photoluminescence, thermal and surface properties of triarylimidazole-containing polyimide nanocomposite films.

In this work, a triarylimidazole-containing diamine 2-(4-methylphenyl)-4,5-bis(4-(4-amino-2-trifluoromethylphenoxy)phenyl)imidazole (MPBAI) was firstly synthesized and polymerized with 1,2,3,4-cyclobutanetetracarboxylic dianhydride (CBDA) to prepare transparent polyimide (PI) films by means of thermal imidization. Then, inorganic nanoparticles including silica (SiO2), alumina (Al2O3) and silicon nitride (Si3N4) were separately introduced into the PI(MPBAI-CBDA) with different mass fractions of 0.02%, 0.10%, 0.50% and 2.50% to obtain three series of PI nanocomposite films. All these films were close to colorless and transparent, although the light transmittance showed a downward trend due to the introduction of nanoparticles. Moreover, as the content of inorganic nanoparticles increased, the fluorescence intensities of these films were increased. Comparatively, the improvement effect of nano-SiO2 was the most obvious. When the content of SiO2 was 2.50%, the maximum intensity of the fluorescence absorption peak was increased by 9.6 times, and the absolute fluorescence quantum yield reached 17.2%, about 5.2 times that of the original PI film. Moreover, the maximum absorption peak produced a red shift of 85 nm due to the addition of 2.50% Si3N4, which was probably caused by the weakening of fluorescence quenching effect and high permittivity. The nanocomposites exhibited high glass transition temperatures of around 300 °C and excellent thermal stabilities. The surface hydrophobicity was changed by adjusting the mass and type of nanoparticles. Thus, this work provided a simple way to improve the photoluminescence effect by introducing the nanoparticles. The functional films will be expected to be applied in some optical applications.

Access Control Model Based on Time Synchronization Trust in Wireless Sensor Networks.

Internal reliability and external safety of Wireless Sensor Networks (WSN) data transmission have become increasingly outstanding issues with the wide applications of WSN. This paper proposes a new method for access control and mitigation of interfering noise in time synchronization environments. First, a formal definition is given regarding the impact interference noise has on the clock skew and clock offset of each node. The degree of node interference behavior is estimated dynamically from the perspective of time-stamp changes caused by the interference noise. Secondly, a general access control model is proposed to resist invasion of noise interference. A prediction model is constructed using the Bayesian method for calculating the reliability of neighbor node behavior in the proposed model. Interference noise, which attacks the time synchronization, is regarded as the key factor for probability estimation of the reliability. The result of the calculations determines whether it is necessary to initiate synchronization filtering. Finally, a division of trust levels with bilinear definition is employed to lower interference noise and improve the quality of interference detection. Experimental results show that this model has advantages in system overhead, energy consumption and testing errors, compared to its counterparts. When the disturbance intensity of a WSN increases, the proposed optimized algorithm converges faster with a lower network communication load.

Silica-supported polymeric monolithic column with a mixed mode of hydrophilic and strong cation-exchange interactions for microcolumn liquid chromatography.

A novel sulfonic acid group containing hydrophilic strong cation-exchange monolith was prepared by in situ coating 5 µm bare silica particles with the copolymers of glycidyl methacrylate and pentaerythritol triacrylate and further sulfonating the prepared polymer matrix with Na2 SO3 inside a 150 µm id capillary. The preparation conditions were investigated, and the method was described in detail. The prepared column was characterized by comparing with its counterparts reported previously in terms of matrix morphology, preparation reproducibility, permeability, swelling-shrinking behavior, mechanical stability, hydrophilicity, binding capacity, and column efficiency. The swelling-shrinking behavior of the present column in solvents of different polarities was negligible, the hydrophobicity could be suppressed at the acetonitrile concentrations higher than 40% v/v, and the binding capacities were 256 µequiv/mL and 20.1 mg/mL for Cu2+ and lysozyme, respectively. The minimum theoretical plate heights were 8, 10, and 13 µm, and the values of the C term in van Deemter equation were 9, 12, and 35 ms for the test analytes of Na+ , thiourea, and cytidine 5'-monophosphate, respectively. This column exhibited an excellent performance in the separations of monovalent inorganic cations, uncharged polar, and charged polar compounds.

[Identification and genetic characteristics on the bacteria isolate from a case of human Brucellosis in Guizhou province].

OBJECTIVE: A suspected Brucella (B.) strain(GZZA), isolated from a case of anti-Brucella antibody positive patient was identified and its' genetic characteristics was analyzed, to provide etiologic basis for the confirmation of patient in Guizhou province. METHODS: Conventional methods and polymerase chain reaction(PCR)were used to identify the bacteria strain, with genetic characteristics analyzed by MLVA-16. RESULTS: The bacteria strain was identified as B. melitensis biovar 3 under the conventional and PCR methods. Results from the MLVA-16 analysis indicated that the bacteria strain was closely clustered with B. melitensis biovar 3, and differences of repeated numbers at VNTR loci bruce42, bruce04, bruce09 and bruce16 were also displayed. CONCLUSION: Both traditional and molecular methods to identify one bacteria strain isolated from the human patient as B. melitensis biovar 3 and the genetic characteristics of the strain was closely related to that of B. melitensis biovar 3. Differences of repeated numbers at part of VNTR loci were also showed. The results of this study provided etiologic evidences for the confirmation of Brucella infection of the patient, also providing scientific basis for the control and prevention of Brucellosis in Guizhou province.

Emulsion PCR-based method to detect Y chromosome microdeletions.

Deletions in Y chromosome are thought to be pathologically involved in some cases of male infertility associated with azoospermia or oligozoospermia. An emulsion-based multiplex PCR method was developed for detecting Y chromosome microdeletions in infertile men and a plasma sample of pregnant women carrying a male fetus. The sensitivity of multiplex PCR in emulsion was evaluated. Conventional PCR was also carried out for comparison. A total of 13 sequence-tagged sites (STSs) distributed in the AZF region were analyzed simultaneously with this method. The SRY gene was also detected as the inner control. Results showed that Y chromosome microdeletions were found in 4 of 19 infertile patients. Also, in 1 of 63 samples collected from pregnant women, microdeletions were found in some of the detected sites. It is suggested that the emulsion PCR assay was proven to be a promising diagnostic tool and could be widely used in further clinical and academic research.

Detection of fetal DNA in maternal plasma by microarray coupled with emulsions PCR.

BACKGROUND: The presence of fetal DNA in maternal plasma made non-invasive prenatal diagnosis possible. Although fetal DNA has been used in several genetic disease diagnoses, many challenges remained in the detection methods. We attempted to develop a sensitive and reliable microarray coupled with emulsions PCR method to detect the fetal DNA in the plasma of pregnant women. METHOD: Fetal DNAs extracted from the plasma of pregnant women were amplified in emulsions, and fluorescence was labeled at the same time. The labeled target DNAs were hybridized and detected by the capturing DNA probes on a modified slide. Six Y chromosome special sequences in gene of SRY, DYS and DYZ as the marker of fetal DNAs were detected simultaneously in this study, and the beta-globin gene was detected as marker of total DNA from maternal plasma. An unrelated sequence was also detected as negative control in this study. 76 pregnant women in the first trimester of gestation joined in this study. Conventional PCR and real time PCR were also carried out for comparison. RESULTS: We could detect the fetal DNAs reliably with this method in early stage of gestation. The 6Y chromosome sequences were detected in 40 of the 42 male fetus carrier samples, and no Y special sequence was detected in the female fetus carrier samples. The earliest plasma sample which we could detect in this study was collected on the 31st day after pregnancy. CONCLUSIONS: The results suggest that the microarray coupled with emulsions PCR method could be used for fetal DNA detections, and emulsions were useful in DNA amplification as reaction media to overcome the primer incompatibility which frequently encounters in multiplex PCR amplification. Our methods have the potential in high-throughput assays and could be widely used in clinical researches and diagnosis.