Global research trends and prospects of cellular metabolism in colorectal cancer.

BACKGROUND: An increasing number of studies have focused on the role of cellular metabolism in the development of colorectal cancer (CRC). However, no work is currently available to synthesize the field through bibliometrics. AIM: To analyze the development in the field of "glucose metabolism" (GM), "amino acid metabolism" (AM), "lipid metabolism" (LM), and "nucleotide metabolism" (NM) in CRC by visualization. METHODS: Articles within the abovementioned areas of GM, AM, LM and NM in CRC, which were published from January 1, 1991, to December 31, 2022, are retrieved from the Web of Science Core Collection and analyzed by CiteSpace 6.2.R4 and VOSviewer 1.6.19. RESULTS: The field of LM in CRC presented the largest number of annual publications and the fastest increase in the last decade compared with the other three fields. Meanwhile, China and the United States were two of the most prominent contributors in these four areas. In addition, Gang Wang, Wei Jia, Maria Notarnicola, and Cornelia Ulrich ranked first in publication numbers, while Jing-Yuan Fang, Senji Hirasawa, Wei Jia, and Charles Fuchs were the most cited authors on average in these four fields, respectively. "Gut microbiota" and "epithelial-mesenchymal transition" emerged as the newest burst words in GM, "gut microbiota" was the latest outburst word in AM, "metastasis", "tumor microenvironment", "fatty acid metabolism", and "metabolic reprogramming" were the up-to-date outbreaking words in LM, while "epithelial-mesenchymal transition" and "apoptosis" were the most recently occurring words in NM. CONCLUSION: Research in "cellular metabolism in CRC" is all the rage at the moment, and researchers are particularly interested in exploring the mechanism to explain the metabolic alterations in CRC. Targeting metabolic vulnerability appears to be a promising direction in CRC therapy.

Cyclic Trinickel(II) Clusters in a Metal-Azolate Framework for Efficient Overall Water Splitting.

Herein, a stable metal-azolate framework with cyclic trinickel(II) clusters, namely [Ni3 (µ3 -O)(BTPP)(OH)(H2 O)2 ] (Ni-BTPP, H3 BTPP=1,3,5-tris((1H-pyrazol-4-yl)phenylene)benzene), achieved a current density of 50 mA cm-2 at a cell voltage of 1.8 V in 1.0 M KOH solution, while the current density of 20%Pt/C@NF||IrO2 @NF is just 35.8 mA cm-2 at 2.0 V under the same condition. Moreover, no obvious degradation was observed over 12 hours of continuous operation at a large current density of 50 mA cm-2 . Theoretical calculations revealed that the µ3 -O atom in the cyclic trinickel(II) cluster serves as hydrogen-bonding acceptor to facilitate the dissociation of a H2 O molecule adsorbed on the adjacent Ni(II) ion, giving a lower energy barrier of H2 O dissociation compared with Pt/C; meanwhile, the µ3 -O atom can also participate in the water oxidation reaction to couple with the adjacent *OH adsorbed on Ni(II) ion, providing a low-energy coupling pathway, thus Ni-BTPP achieves a high performance for overall water splitting.

Single-Product Faradaic Efficiency for Electrocatalytic of CO2 to CO at Current Density Larger than 1.2†A cm-2 in Neutral Aqueous Solution by a Single-Atom Nanozyme.

Electroreduction of CO2 to CO is a promising approach for the cycling use of CO2 , while it still suffers from impractical current density and durability. Here we report a single-atom nanozyme (Ni-N5 -C) that achieves industrial-scale performance for CO2 -to-CO conversion with a Faradaic efficiency (FE) exceeded 97 % over -0.8--2.4 V vs. RHE. The current density at -2.4 V vs. RHE reached a maximum of 1.23 A cm-2 (turnover frequency of 69.7 s-1 ) with an FE of 99.6 %. No obvious degradation was observed over 100 hours of continuous operation. Compared with the planar Ni-N4 site, the square-pyramidal Ni-N5 site has an increase and a decrease in the d z 2 ${{{\rm d}}_{{z}^{2}}}$ and dxz/yz orbital energy levels, respectively, as revealed by density functional theory calculations. Thus, the Ni-N5 catalytic site is more superior to activate CO2 molecule and reduce the energy barriers as well as promote the CO desorption, thus boosting the kinetic activation process and catalytic activity.

Neuroinflammation inhibition by small-molecule targeting USP7 noncatalytic domain for neurodegenerative disease therapy.

Neuroinflammation is a fundamental contributor to progressive neuronal damage, which arouses a heightened interest in neurodegenerative disease therapy. Ubiquitin-specific protease 7 (USP7) has a crucial role in regulating protein stability in multiple biological processes; however, the potential role of USP7 in neurodegenerative progression is poorly understood. Here, we discover the natural small molecule eupalinolide B (EB), which targets USP7 to inhibit microglia activation. Cocrystal structure reveals a previously undisclosed covalent allosteric site, Cys576, in a unique noncatalytic HUBL domain. By selectively modifying Cys576, EB allosterically inhibits USP7 to cause a ubiquitination-dependent degradation of Keap1. Keap1 function loss further results in an Nrf2-dependent transcription activation of anti-neuroinflammation genes in microglia. In vivo, pharmacological USP7 inhibition attenuates microglia activation and resultant neuron injury, thereby notably improving behavioral deficits in dementia and Parkinson's disease mouse models. Collectively, our findings provide an attractive future direction for neurodegenerative disease therapy by inhibiting microglia-mediated neuroinflammation by targeting USP7.

Occurrence and decay of SARS-CoV-2 in community sewage drainage systems.

The rapid spread of the coronavirus disease (COVID-19) pandemic in over 200 countries poses a substantial threat to human health. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes COVID-19, can be discharged with feces into the drainage system. However, a comprehensive understanding of the occurrence, presence, and potential transmission of SARS-CoV-2 in sewers, especially in community sewers, is still lacking. This study investigated the virus occurrence by viral nucleic acid testing in vent stacks, septic tanks, and the main sewer outlets of community where confirmed patients had lived during the outbreak of the epidemic in Wuhan, China. The results indicated that the risk of long-term emission of SARS-CoV-2 to the environment via vent stacks of buildings was low after confirmed patients were hospitalized. SARS-CoV-2 were mainly detected in the liquid phase, as opposed to being detected in aerosols, and its RNA in the sewage of septic tanks could be detected for only four days after confirmed patients were hospitalized. The surveillance of SARS-CoV-2 in sewage could be a sensitive indicator for the possible presence of asymptomatic patients in the community, though the viral concentration could be diluted more than 10 times, depending on the sampling site, as indicated by the Escherichia coli (E. coli) test. The comprehensive investigation of the community sewage drainage system is helpful to understand the occurrence characteristics of SARS-CoV-2 in sewage after excretion with feces and the feasibility of sewage surveillance for COVID-19 pandemic monitoring.

Acute Toxicity and Hepatotoxicity of Aqueous Extracts of Taxilli Herba from Different Hosts in Zebrafish Model / 中国实验方剂学杂志

Objective:To explore the acute toxicities and hepatotoxicities of aqueous extracts of Taxilli Herba from <italic>Morus alba</italic>， <italic>Toxicodendron</italic> <italic>trichocarpum</italic>， <italic>Camellia oleifera</italic>， <italic>Salix babylonica</italic>， <italic>Melia azedarach</italic>， and <italic>Nerium indicum</italic> against zebrafish model and the effect of different hosts on the toxicity of Taxilli Herba， hoping to provide a theoretical basis for the safe use of Taxilli Herba. Method:The normally developed AB zebrafish at 3-day post fertilization was selected for acute toxicity study. According to the results of preliminary toxicity experiments， the zebrafishes were treated with aqueous extracts of Taxilli Herba from different hosts at six doses， and their mortality was calculated 72 h later. GraphPad Prism 6.0 was used for plotting the dose-toxicity curve， followed by the calculation of their median lethal concentration （LC₅₀） and 10% lethal concentration （LC₁₀）. The gz15Tg/+（AB） liver fluorescent protein transgenic zebrafish with normal development at 4-day post fertilization was applied for the hepatotoxicity study. The zebrafishes were divided into the low-， medium-， and high-dose groups of aqueous extracts of Taxilli Herba from six hosts， the positive control （acetaminophen） group， and the blank （embryo amniotic fluid） group， and then treated with the corresponding drugs. Seventy-two hours later， the liver morphology and fluorescent area changes in zebrafish were observed. And the activities of alanine aminotransferase （ALT） and aspartate aminotransferase （AST） were detected. Result:The results of acute toxicity test demonstrated that the LC₅₀ values of water extracts of Taxilli Herba from <italic>M. alba</italic>， <italic>T.</italic> <italic>trichocarpum</italic>， <italic>C. oleifera</italic>， <italic>S. babylonica</italic>， <italic>M. azedarach</italic>， and <italic>N. indicum</italic> were 1.24， 0.94， 0.51， 0.38， 0.11， 0.09 g·L^-1， respectively， and the LC₁₀ values were 0.70， 0.60， 0.35， 0.28， 0.08， 0.07 g·L^-1， respectively. As revealed by hepatotoxicity test， compared with the blank group， the positive control group exhibited liver morphological changes， decreased fluorescent area （<italic>P</italic><0.01）， and elevated ALT and AST activities （<italic>P</italic>< 0.01）， suggesting that acetaminophen was hepatotoxic to zebrafish. However， there was no change in the liver morphology or fluorescent area of zebrafish in the low-， medium-， and high-dose groups of water extracts of Taxilli Herba from <italic>M. alba</italic>， and the ALT and AST activities were decreased. By contrast， the liver morphology and fluorescent areas in the medium- and high-dose groups of water extracts of Taxilli Herba from <italic>T.</italic> <italic>trichocarpum</italic>， <italic>C. oleifera</italic>， <italic>S. babylonica</italic>， <italic>M. azedarach</italic>， and <italic>N. indicum</italic> changed to varying degrees （<italic>P</italic><0.05， <italic>P</italic><0.01）. Besides， the activities of both ALT and AST were also enhanced. These indicated that Taxilli Herba from <italic>M. alba</italic> had no hepatotoxicity to zebrafish， while that from <italic>T.</italic> <italic>trichocarpum</italic>， <italic>C. oleifera</italic>， <italic>S. babylonica</italic>， <italic>M. azedarach</italic>， and <italic>N. indicum</italic> showed varying degrees of hepatotoxicity to zebrafish. Conclusion:The toxicity of Taxilli Herba is host-dependent. Taxilli Herba from <italic>M. alba</italic> has no hepatotoxicity， but that from the other five hosts shows varying degrees of hepatotoxicity. Standardizing the host source may be an important measure to realize the medication safety of Taxilli Herba.

Costunolide Plays an Anti-Neuroinflammation Role in Lipopolysaccharide-Induced BV2 Microglial Activation by Targeting Cyclin-Dependent Kinase 2.

Hyperactivation of microglia in the brain is closely related to neuroinflammation and leads to neuronal dysfunction. Costunolide (CTL) is a natural sesquiterpene lactone with wide pharmacological activities including anti-inflammation and antioxidation. In this study, we found that CTL significantly inhibited the production of inflammatory mediators including nitric oxide, IL-6, TNF-α, and PGE2 in lipopolysaccharide (LPS)-stimulated BV2 microglia. Moreover, CTL effectively attenuated IKKß/NF-κB signaling pathway activation. To identify direct cellular target of CTL, we performed high-throughput reverse virtual screening assay using scPDB protein structure library, and found cyclin-dependent kinase 2 (CDK2) was the most specific binding protein for CTL. We further confirmed the binding ability of CTL with CDK2 using cellular thermal shift assay (CETSA) and drug affinity responsive target stability (DARTS) assays. Surface plasmon resonance analysis also supported that CTL specifically bound to CDK2 with a dissociation constant at micromole level. Furthermore, knocking down CDK2 obviously reversed the anti-inflammation effect of CTL via AKT/IKKß/NF-κB signaling pathway on BV-2 cells. Collectively, these results indicate that CTL inhibits microglia-mediated neuroinflammation through directly targeting CDK2, and provide insights into the role of CDK2 as a promising anti-neuroinflammation therapeutic target.

Postoperative Adjuvant Transarterial Chemoembolization Improves Outcomes of Hepatocellular Carcinoma Associated with Hepatic Vein Invasion: A Propensity Score Matching Analysis.

BACKGROUND: Vascular invasion is a major determinant of survival outcomes after curative resection for hepatocellular carcinoma (HCC) patients. This study was designed to investigate the efficacy of postoperative adjuvant transarterial chemoembolization (PA-TACE) in patients with HCC with hepatic vein tumor thrombus (HVTT). METHODS: Data from patients who underwent LR for HCC with HVTT at the Eastern Hepatobiliary Surgery Hospital were retrospectively analyzed. The survival outcomes for patients who underwent PA-TACE after LR were compared with those who underwent LR alone. Propensity score matching (PSM) analysis was performed to match patients in a ratio of 1:1. RESULTS: All included 319 patients who underwent LR for HCC with HVTT, 134 underwent LR alone (the LR group), and 185 patients underwent in adjuvant TACE (the PA-TACE group). PSM matched 107 patients in two groups. The overall survival (OS) and recurrence-free survival (RFS) were significantly better for patients in the PA-TACE group than the LR group (for OS: before PSM, P < 0.001; after PSM, P = 0.004; for RFS: before PSM, P < 0.001; after PSM, P = 0.013), respectively. On subgroup analysis, equivalent acceptable results were obtained in patients with peripheral HVTT (pHVTT) and major HVTT (mHVTT). However, PA-TACE resulted in no survival benefits for patients when the HVTT had extended to the inferior vena cava (IVCTT). CONCLUSIONS: PA-TACE was associated with significantly better survival outcomes than LR alone for patients with HCC and HVTT (pHVTT and mHVTT). There was no survival benefits in patients whose HVTT had extended to form IVCTT.

[Wastewater Quantity and Quality Fluctuation Characteristics of Typical Area of Hybrid Sewage System].

The inflow and infiltration problems cause large fluctuation in wastewater quantity and quality in hybrid sewage system. This seriously challenges the operation and management of sewage system. A multi-point on-line simultaneous monitoring system was established in a typical hybrid sewage system. The key characteristic parameters and their variation features under different circumstances were studied. The result indicated that the daily variation rule was obvious and appeared synchronous among multiple points at normal water level under dry weather flow, but there was no synchronization in conductivity variation among multiple points at high water level under dry weather flow. The statistical distribution range of water level and conductivity was significantly impacted by the seasonal rainfall change under dry weather. The statistical distribution ranges of water level variation rate and conductivity variation rate in specific time were significantly impacted by the rainfall. The response features of water level and conductivity to rainfall intensity and pattern were significantly different under different circumstances. The response sensitivity of conductivity was higher than water level at normal water level and lower at high water level. The database which could support the optimization of operation and management in the hybrid sewage system was proposed based on the distribution law of wastewater quality and quantity fluctuation under dry and wet weather, as well as the variation rate features of wastewater quality and quantity during rainfall obtained using the multi-point on-line simultaneous monitoring system.

Role of Berberine in the Treatment of Methicillin-Resistant Staphylococcus aureus Infections.

Berberine is an isoquinoline alkaloid widely used in the treatment of microbial infections. Recent studies have shown that berberine can enhance the inhibitory efficacy of antibiotics against clinical multi-drug resistant isolates of methicillin-resistant Staphylococcus aureus (MRSA). However, the underlying mechanisms are poorly understood. Here, we demonstrated that sub-minimum inhibitory concentrations (MICs) of berberine exhibited no bactericidal activity against MRSA, but affected MRSA biofilm development in a dose dependent manner within the concentration ranging from 1 to 64 µg/mL. Further study indicated that berberine inhibited MRSA amyloid fibrils formation, which consist of phenol-soluble modulins (PSMs). Molecular dynamics simulation revealed that berberine could bind with the phenyl ring of Phe19 in PSMα2 through hydrophobic interaction. Collectively, berberine can inhibit MRSA biofilm formation via affecting PSMs' aggregation into amyloid fibrils, and thereby enhance bactericidal activity of antibiotics. These findings will provide new insights into the multiple pharmacological properties of berberine in the treatment of microbial-generated amyloid involved diseases.

Ultrasonic Treatment Enhanced Ammonia-Oxidizing Bacterial (AOB) Activity for Nitritation Process.

Oxidation of ammonia to nitrite rather than nitrate is critical for nitritation process for wastewater treatment. We proposed a promising approach by using controlled ultrasonic treatment to enhance the activity of ammonia-oxidizing bacteria (AOB) and suppress that of nitrite-oxidizing bacteria (NOB). Batch activity assays indicated that when ultrasound was applied, AOB activity reached a peak level and then declined but NOB activity deteriorated continuously as the power intensity of ultrasound increased. Kinetic analysis of relative microbial activity versus ultrasonic energy density was performed to investigate the effect of operational factors (power, sludge concentration, and aeration) on AOB and NOB activities and the test parameters were selected for reactor tests. Laboratory sequential batch reactor (SBR) was further used to test the ultrasonic stimulus with 8 h per day operational cycle and synthetic waste urine as influent. With specific ultrasonic energy density of 0.09 kJ/mg VSS and continuously fed influent containing above 200 mg NH3-N/L, high AOB reproductive activity was achieved and nearly complete conversion of ammonia-N to nitrite was maintained. Microbial structure analysis confirmed that the treatment changed community of AOB, NOB, and heterotrophs. Known AOB Nitrosomonas genus remained at similar level in the biomass while typical NOB Nitrospira genus disappeared in the SBR under ultrasonic treatment and after the treatment was off for 30 days.

Tetraphenylethene Derivatives with Different Numbers of Positively Charged Side Arms have Different Multimeric G-Quadruplex Recognition Specificity.

Some G-rich sequences in the human genome have the potential to fold into a multimeric G-quadruplex (G4) structure and the formation of telomeric multimeric G4 has been demonstrated. Searching for highly specific multimeric G4 ligands is important for structure probing and for study of the function of G-rich gene sequences, as well as for the design of novel anticancer drugs. We found different numbers of positively charged side-arm substituents confer tetraphenylethene (TPE) derivatives with different multimeric G4 recognition specificity. 1,2-Bis{4-[(trimethylammonium)butoxy]phenyl}-1,2-tetraphenylethene dibromide (DATPE), which contains two side arms and gives a fluorescence response to only multimeric G4, has a low level of cytotoxicity and little or no effect on multimeric G4 conformation or stability. These features make DATPE a promising fluorescent probe for detection of multimeric G4 specifically in biological samples or in vivo. 1,1,2,2-Tetrakis{4-[(trimethylammonium)butoxy]phenyl}tetraphenylethene tetrabromide (QATPE), which contains four side arms, has a lower level of specificity for multimeric G4 recognition compared to DATPE but its binding affinity to multimeric G4 is higher compared to other structural DNAs. Its high multimeric G4-binding affinity, excellent multimeric G4-stabilizing ability, and the promotion of parallel G4 formation make QATPE a good candidate for novel anticancer drugs targeting multimeric G4 specifically, especially telomeric multimeric G4. This work provides information that might aid the design of specific multimeric G4 probes and the development of novel anticancer drugs.

Aggregation behavior of engineered nanoparticles and their impact on activated sludge in wastewater treatment.

The ever-increasing daily use of engineered nanoparticles will lead to heightened levels of these materials in the environment. These nanomaterials will eventually go into the wastewater treatment plant (WWTP), therefore, resulting into a pressing need for information on their aggregation behavior and kinetics in the wastewater aqueous matrix. In this work, we dispersed two different metal oxide nanoparticles (ZnO and TiO2) into the influent of two different WWTPs. Through the time-resolved dynamic light scattering analysis and transmission electron microscopy, the metal oxide nanoparticles (NPs) were quite stably existed in the wastewater matrix with aggregates of diameter 300-400 nm after 4.5h or more suspension. We confirmed that the dissolved organic matters (DOMs) attributed to the stability of nanoparticles. No propensity of NPs to aggregate were observed in the presence of both monovalent and divalent electrolytes even at high concentrations up to 0.15 M in NaCl or 0.025 M in CaCl2, indicating that the destabilization of nanoparticles in the complicated wastewater matrix was not achieved by the compression of electrical double layer, therefore, their aggregation kinetics cannot be simply predicted by the classic Derjaguin-Landau-Verwey-Overbeek theory of colloidal stability. However, obvious aggregation of nanoparticles in the Al2(SO4)3 solution system was observed with the likely mechanism of bridging of the metal oxide nanoparticles and aggregates due to the formation of hydrous alumina (Al(OH)3·H2O) in the Al2(SO4)3 solution. In the wastewater matrix, we used the noninvasive measurement technology to detect the O2 flux of activated sludge before and after treatment with 1, 10 and 100 mg L(-1) NPs. The results confirmed that both ZnO and TiO2 NPs showed an adverse impact on the O2 uptake of activated sludge when the exposure time extended to 4.5 h.

Study on enhanced denitrification using particulate organic matter in membrane bioreactor by mechanism modeling.

Particulate organic matter (POM) in wastewater is a potential denitrification carbon source, while the optimal operational mode using denitrification mechanism with POM is still unclear in wastewater treatment plants. In this work, we investigated the denitrification rates (DNRs) in a full-scale membrane bioreactor (MBR) coupled with two-stage pre-anoxic (pre-AN), and then evaluated the POM denitrification efficiency using mechanism modeling. The results indicate that POM related fraction accounted for the majority of the obtained specific DNR of 1.39±0.46mgNg(-1) MLVSS h(-1) in the second pre-AN without available soluble carbon source. The modeling approaches with calibration and validation procedures estimated a high residual POM concentration of 0.17g COD g(-1) MLVSS in the activated sludge, which provided specific DNR of 1.14mgNg(-1) MLVSS h(-1). High POM retention time in the reactor was the result of high solid retention time used in the MBR. In particular, post-AN of high biomass concentration could provide the highest POM denitrification efficiency in MBR. The MBR process combined with additional sludge reduction technology could further enhance denitrification by POM.

Use of low frequency and density ultrasound to stimulate partial nitrification and simultaneous nitrification and denitrification.

Low frequency and density ultrasound has attracted considerable attention in enhancing wastewater treatment performance, particularly in the removal of nitrogen. In the present study, two sequencing batch reactors were operated to confirm the effects of ultrasound at the frequency of 40 kHz and density of 0.027 W/mL on partial nitrification and simultaneous nitrification and denitrification (SND). At the optimal irradiation time of 2.0 h, the obtained nitrite accumulation ratio and SND efficiency at full aerobic were 73.9% and 72.8%, respectively. Nitrite accumulation was the result of increased NH4(+)-N removal and improved ammonia oxidizing bacteria (AOB) activity with simultaneous inhibition of nitrite oxidizing bacteria (NOB) activity. Ultrasonic treatment could provide suitable conditions in temperature and pH for AOB growth, and destroy the NOB community structure. Moreover, organic matters were released and offered an additional carbon source for denitrification apart from the negative effects on sludge properties.

[Optimization and assessment of a reverse hybridization system for the detection of HBV drug-resistant mutations].

OBJECTIVE: To establish a detection method for HBV drug-resistant mutations related to lamivudine, adefovir and entecavir by optimization and assessment of reverse hybridization system. METHOD: 26 degenerated probes covering 10 drug-resistant hotspots of 3 drugs were synthesized and immobilized on the same positively charged nylon membrane. PCR products labeled with digoxigenin were hybridized with corresponding probes. To improve the sensitivity and specificity, 4 reaction steps of reverse hybridization were optimized including the number of labeled digoxigenin, the energy intensity of UV cross-linking, hybridization and stringency wash conditions. To prove the feasibility, the specificity, sensitivity and accuracy of this system were assessed respectively. RESULT: Sensitive and specific results are obtained by the optimization of the following 4 reaction steps: the primers labeled with 3 digoxigenin, energy intensity of UV cross-linking for 1500 x 0.1 mJ/cm², hybridization at 42 degrees C and stringency wash with 0.5 x SSC and 0.1% SDS solution at 44 degrees C for 30 min. In the assessment of system, the majority of probes have high specificity. The quantity of PCR product with a concentration of 10 ng/µl or above can be detected by this method. The concordant rate between reverse hybridization and direct sequencing is 93.9% in the clinical sample test. CONCLUSION: Though the specificity of several probes needs to be improved further, it is a simple, rapid and sensitive method which can detect HBV resistant mutations related to lamivudine, adefovir and entecavir simultaneously. Due to the short distance between 180 and 181, likewise 202 and 204, the sequence of the same probe covers two codon positions, and hybridization will be interfered by each other. To avoid such interference, the possible solution is that probes are designed by arranging and combining various forms of two near codons.

[Detection of HBV resistant mutations related to lamivudine, adefovir and entecavir by reverse hybridization technique].

OBJECTIVES: To establish a method for simultaneous detection of HBV resistant mutations associated with three kinds of nucleoside analogues. METHODS: According to 981 HBV complete sequences in GenBank, two pairs of conserved primers labeled with digoxigenin were synthesized to amplify the region of HBV reverse transcriptase. To detect non-synonymous amino acid substitutions associated with lamivudine, adefovir and entecavir, 26 specific oligonucleotide probes covering ten different codon positions, I169T, V173L/G, L180M, A181T/V, T184G, S202I/G, M204V/I, Q215S, N236T and M250V/I/L were synthesized and immobilized on nylon membranes charged positively. The oligonucleotide probes immobilized on nylon membranes were then hybridized with PCR products labeled with digoxigenin to detect three drug-resistant mutations. In order to observe specificity and accuracy of probes, HBV wild-type, resistant reference strains and patients serums were assayed by reverse hybridization technique, respectively. RESULTS: The specific probes of 10 codon positions related to HBV wild-type and resistant reference strains, including I169T, V173L, L180M, A181T, T184G, S202I, M204V, Q215S, N236T, M250V, were distinguished effectively by reverse hybridization method. The results results of 37 samples applicated the method were in accordance with that Of DNA sequencing. CONCLUSION: Reverse hybridization technique can be applied to detect HBV resistant mutations associated with Lamivudine, Adefovir and Entecavir rapidly and accurately.

Fast support vector data descriptions for novelty detection.

Support vector data description (SVDD) has become a very attractive kernel method due to its good results in many novelty detection problems. However, the decision function of SVDD is expressed in terms of the kernel expansion, which results in a run-time complexity linear in the number of support vectors. For applications where fast real-time response is needed, how to speed up the decision function is crucial. This paper aims at dealing with the issue of reducing the testing time complexity of SVDD. A method called fast SVDD (F-SVDD) is proposed. Unlike the traditional methods which all try to compress a kernel expansion into one with fewer terms, the proposed F-SVDD directly finds the preimage of a feature vector, and then uses a simple relationship between this feature vector and the SVDD sphere center to re-express the center with a single vector. The decision function of F-SVDD contains only one kernel term, and thus the decision boundary of F-SVDD is only spherical in the original space. Hence, the run-time complexity of the F-SVDD decision function is no longer linear in the support vectors, but is a constant, no matter how large the training set size is. In this paper, we also propose a novel direct preimage-finding method, which is noniterative and involves no free parameters. The unique preimage can be obtained in real time by the proposed direct method without taking trial-and-error. For demonstration, several real-world data sets and a large-scale data set, the extended MIT face data set, are used in experiments. In addition, a practical industry example regarding liquid crystal display micro-defect inspection is also used to compare the applicability of SVDD and our proposed F-SVDD when faced with mass data input. The results are very encouraging.