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Abstract Helicobacter pylori (H. pylori) infection has been found associated with Alzheimer’s disease (AD) with unclear mechanisms. Outer Membrane Vesicles (OMVs) are spherical particles secreted by Gram-negative bacteria. Here we explore the effect of H. pylori OMVs on Aβ aggregation and toxicity. We show intraperitoneally-injected H. pylori OMVs enter the brain and co-localize with Aβ plaques in APP/PS1 mice, accompanied by aggravated Aβ pathology, exacerbated cognitive deficits and synaptic impairment, indicating that H. pylori OMVs promote β-amyloidosis and AD development. The in vitro results further identify that H. pylori OMVs significantly accelerate Aβ aggregation and increase Aβ-induced neurotoxicity. Through lipidomic analysis, we reveal that lipid components, particularly LPC 18:0 in H. pylori OMVs accelerate Aβ aggregation and enhance Aβ neurotoxicity. Moreover, H. pylori OMVs-enhanced Aβ neurotoxicity is mediated by Ca2+. These findings reveal a mechanism of H. pylori OMVs in accelerating AD development in which the bacterial OMVs-originated lipid components play a key role in promoting Aβ aggregation and neurotoxicity.

ObjectivesCancer-related fatigue (CRF) is a prevalent and distressing symptom experienced by many cancer patients, necessitating effective treatments. This study utilizes meta-analysis and network pharmacology to comprehensively assess the efficacy of the Buzhong Yiqi prescription in alleviating cancer-related fatigue and to preliminarily explore the mechanism of its core drugs.MethodsWe included randomized controlled trials (RCTs) in cancer patients. The inclusion criteria encompassed a diagnosis of cancer-related fatigue, without limitation on cancer type, the experimental group receiving Buzhong Yiqi prescription, the control group receiving conventional treatment, patients awaiting treatment, and articles published in either English or Chinese. We conducted a search through 29 February 2024, across PubMed, Cochrane Database of Systematic Reviews, Cochrane Controlled Clinical Trials (CENTRAL), China Biomedical Literature Service (CBM), China National Knowledge Infrastructure (CNKI), WANFANG Database, and Weipu Database (VIP). Journal articles that met the inclusion criteria were selected for inclusion. Two independent investigators evaluated the quality of the included studies. A meta-analysis was performed utilizing the Stata 12.0 software package, where estimates of cancer-related fatigue were aggregated through the application of a random-effects model. We employed the Cochrane Risk of Bias Tool to evaluate potential biases in RCTs. The primary outcome measures utilized to assess the efficacy and safety of CRF treatment comprised the Revised Piper Fatigue Scale (PFS-R) and the Quality of Life Questionnaire Core 30 (EORTC QLQ-C30). The secondary outcomes encompassed the KPS score, the effective rate, the TCM syndrome score, and an evaluation of adverse reactions. The Traditional Chinese Medicine Systems Pharmacology (TCMSP) was utilized to identify the active ingredients and targets of BZD. Additionally, the Drug bank, Therapeutic Target Database (TTD), DiaGeNET, and GeneCards databases were utilized to retrieve relevant targets for CRC. The Venn diagram was employed to identify overlapping targets. Cytoscape software was utilized to construct a network of “herb-ingredient-target” and identify core targets. GO and KEGG pathway enrichment analyses were performed using R language software.ResultsIn comparison to the control group, patients with CRF who received BZYQ prescription exhibited marked improvements in KPS score, QLQ-C30 quality of life score, and effective rate. Conversely, PFS, TCM syndrome score, and adverse reaction assessments significantly decreased. The primary active ingredients in its core drugs may exert a positive therapeutic effect on CRF by targeting molecules such as AKT1, IL6, IL1B, PTGS2, CASP3, ESR1, and BCL2, as well as through signaling pathways including TNF, IL17, TLR, NF-κB, and C-type lectin receptor.ConclusionBZYQ demonstrates significant efficacy in treating CRF with minimal adverse reactions. It can serve as a fundamental treatment for CRF in clinical practice, and the medication can be tailored to individual patients for personalized therapy. The potential pharmacological mechanism of BZYQ in treating CRF, as predicted by network pharmacology, offers a molecular foundation for clinical CRF treatment.Systematic Review Registration:https://inplasy.com, identifier INPLASY202430025

ObjectiveIn this study, we examined the effectiveness of hyperbaric oxygen (HBO) therapy in ameliorating cognitive deficits in mice with Alzheimer’s disease (AD), while also assessing its impact on the autophagic pathway within the context of AD.Methods20 double-transgenic mice expressing the amyloid precursor protein and presenilin 1 (APP/PS1) were purposefully selected and randomly assigned to groups A and B. Concurrently, 20 C57BL/6 mice were chosen and randomly categorized into groups C and D, each consisting of 10 mice. Mice in groups B and D received HBO treatment. The Morris water maze assay was used to assess changes in mouse behavior. Immunohistochemistry techniques were used to quantify the expression levels of amyloid-beta 42 (Aβ42) and microtubule-associated protein 1A/1B-light chain 3 (LC3) in hippocampal tissues, while western blot analysis was used to investigate the levels of LC3-II, p62, phosphoinositide 3-kinase (PI3K), and mammalian target of rapamycin (mTOR) proteins within hippocampal tissues.ResultsMice allocated to group B exhibited reduced escape latency and prolonged dwell time in the target quadrant compared to other groups. Histological examination revealed conspicuous plaque-like deposits of Aβ42 in the hippocampal tissues of mice in groups A and B. Group B displayed diminished Aβ42-positive reactants and augmented microtubule-associated protein 1A/1B-LC3-positive reactants compared to group A. LC3-positive reactants were also detected in the hippocampal tissues of mice in groups C and D, surpassing the levels observed in groups A and B. Furthermore, group B demonstrated significantly lower expression of mTOR protein and markedly higher expression of LC3-II protein in mouse hippocampal tissues when compared to group A (P < 0.05). Conversely, there were no significant disparities noted in PI3K and p62 protein expression between groups B and A. Notably, no discernible discrepancies were observed in the expression levels of mTOR, PI3K, LC3-II, and p62 proteins between groups C and D within mouse hippocampal tissues.ConclusionHBO treatment demonstrates efficacy in enhancing cognitive function in mice with AD and holds promise as a potential therapeutic intervention for AD by facilitating the activation of the mTOR pathway-mediated autophagy.

Abstract Clostridioides difficile is a leading cause of healthcare‐associated infections, causing billions of economic losses every year. Its symptoms range from mild diarrhea to life‐threatening damage to the colon. Transmission and recurrence of C. difficile infection (CDI) are mediated by the metabolically dormant spores, while the virulence of C. difficile is mainly due to the two large clostridial toxins, TcdA and TcdB. Producing toxins or forming spores are two different strategies for C. difficile to cope with harsh environmental conditions. It is of great significance to understand the molecular mechanisms for C. difficile to skew to either of the cellular processes. Here, we summarize the current understanding of the regulation and connections between toxin production and sporulation in C. difficile and further discuss the potential solutions for yet‐to‐be‐answered questions.

Objective: To study the effect of Yujing Jiangtang Recipe on blood glucose, lipid and antioxidation in type 2 diabetes rats. Methods: High fat diet and intraperitoneal injection of 40 mg/kg STZ were used to establish the model of type 2 diabetes rats. The successful rats were randomly divided into diabetes model group, metformin group (0.2 g/kg), low, medium and high dose Yujing Jiangtang Recipe groups (1、2、4 g/kg), and another normal control group with nine rats in each group. The treatment group was gavaged with corresponding dose, the normal control group and the diabetes model group were gavaged with 10 mL/kg normal saline according to weight, and each group was gavaged once a day for six consecutive weeks. During the experiment, observe and record the weight changes of rats in each group, and measure the fasting blood glucose (FBG). After continuous gavage for six weeks, the abdominal aorta blood of rats was taken, the fasting insulin (FINS) level and the percentage content of glycosylated hemoglobin (HbA1c) were measured, and the HOMA-IR, ISI were calculated. The contents of serum TG, TC, HDL-C, LDL-C were measured. The serum levels of MDA, SOD, GSH, NO, GSH-Px and CAT were measured by ELISA. The pancreatic tissue of rats was stained with HE to observe the pathological changes of rats. Results: Compared with the diabetes model group, the body weight of the high dose group of Yujing Jiangtang Recipe increased significantly (P

Abstract Background Alzheimer's disease (AD) and related Tauopathies are characterised by the pathologically hyperphosphorylated and aggregated microtubule‐associated protein Tau, which is accompanied by neuroinflammation mediated by activated microglia. However, the role of Tau pathology in microglia activation or their causal relationship remains largely elusive. Methods The levels of nucleotide‐binding oligomerisation domain (NOD)‐like receptor pyrin domain containing 3 (NLRP3) acetylation and inflammasome activation in multiple cell models with Tau proteins treatment, transgenic mice with Tauopathy, and AD patients were measured by Western blotting and enzyme‐linked immunosorbent assay. In addition, the acetyltransferase activity of Tau and NLRP3 acetylation sites were confirmed using the test‐tube acetylation assay, co‐immunoprecipitation, immunofluorescence (IF) staining, mass spectrometry and molecular docking. The Tau‐overexpressing mouse model was established by overexpression of human Tau proteins in mouse hippocampal CA1 neurons through the adeno‐associated virus injection. The cognitive functions of Tau‐overexpressing mice were assessed in various behavioural tests, and microglia activation was analysed by Iba‐1 IF staining and [18F]‐DPA‐714 positron emission tomography/computed tomography imaging. A peptide that blocks the interaction between Tau and NLRP3 was synthesised to determine the in vitro and in vivo effects of Tau–NLRP3 interaction blockade on NLRP3 acetylation, inflammasome activation, microglia activation and cognitive function. Results Excessively elevated NLRP3 acetylation and inflammasome activation were observed in 3xTg‐AD mice, microtubule‐associated protein Tau P301S (PS19) mice and AD patients. It was further confirmed that mimics of ‘early’ phosphorylated‐Tau proteins which increase at the initial stage of diseases with Tauopathy, including TauT181E, TauS199E, TauT217E and TauS262E, significantly promoted Tau–K18 domain acetyltransferase activity‐dependent NLRP3 acetylation and inflammasome activation in HEK293T and BV‐2 microglial cells. In addition, Tau protein could directly acetylate NLRP3 at the K21, K22 and K24 sites at its PYD domain and thereby induce inflammasome activation in vitro. Overexpression of human Tau proteins in mouse hippocampal CA1 neurons resulted in impaired cognitive function, Tau transmission to microglia and microgliosis with NLRP3 acetylation and inflammasome activation. As a targeted intervention, competitive binding of a designed Tau–NLRP3‐binding blocking (TNB) peptide to block the interaction of Tau protein with NLRP3 inhibited the NLRP3 acetylation and downstream inflammasome activation in microglia, thereby alleviating microglia activation and cognitive impairment in mice. Conclusions In conclusion, our findings provide evidence for a novel role of Tau in the regulation of microglia activation through acetylating NLRP3, which has potential implications for early intervention and personalised treatment of AD and related Tauopathies.

Cruise ships are distinguished as special passenger ships, transporting passengers to various ports and giving importance to comfort. High comfort can attract lots of passengers and generate substantial profits. Vibration and noise are the most important indicators for assessing the comfort of cruise ships. Existing methods for analyzing vibration and noise data have shown limitations in uncovering essential information and discerning critical disparities in vibration and noise levels across different ship districts. Conversely, the rapid development in machine learning present an opportunity to leverage sophisticated algorithms for a more insightful examination of vibration and noise aboard cruise ships. This study designed a machine learning-driven approach to analyze the vibration and noise data. Drawing data from China's first large-scale cruise ship, encompassing 127 noise samples, this study sets up a classification task, where decks were assigned as labels and frequencies served as features. Essential information was extracted by investigating this problem. Several machine learning algorithms, including feature ranking, selection, and classification algorithms, were adopted in this method. One or two essential noise frequencies related to each of the decks, except the 10th deck, were obtained, which were partly validated by the traditional statistical methods. Such findings were helpful in reducing and controlling the vibration and noise in cruise ships. Furthermore, the study develops a classifier to distinguish noise samples, which utilizes random forest as the classification algorithm with eight optimal frequency features identified by LightGBM. This classifier yielded a Matthews correlation coefficient of 0.3415. This study gives a new direction for investigating vibration and noise in ships.

Potato common scab, caused mainly by Streptomyces scabies, causes surface necrosis and reduces the economic value of potato tubers, but effective chemical control is still lacking. In this study, an attempt was made to control potato common scab by inoculating potatoes with Bacillus velezensis (B. velezensis) and to further investigate the mechanism of biological control. The results showed that B. velezensis Y6 could reduce the disease severity of potato common scab from 49.92 ± 25.74% [inoculated with Streptomyces scabies (S. scabies) only] to 5.56 ± 1.89% (inoculated with S. scabies and Y6 on the same day) and increase the potato yield by 37.32% compared with the control under pot experiment in this study. Moreover, in the field trial, it was found that Y6 could also significantly reduce disease severity from 13.20 ± 1.00% to 4.00 ± 0.70% and increase the potato yield from 2.07 ± 0.10 ton/mu to 2.87 ± 0.28 ton/mu (p

Bombesin receptor-activated protein (BRAP) and its homologous protein in mice, which is encoded by bc004004 gene, were expressed abundantly in brain tissues with unknown functions. We treated bc004004-/- mice with chronic unpredictable mild stress (CUMS) to test whether those mice were more vulnerable to stress-related disorders. The results of forced swimming test, sucrose preference test, and open field test showed that after being treated with CUMS for 28 days or 35 days both bc004004-/- and bc004004+/+ mice exhibited behavioural changes and there was no significant difference between bc004004+/+ and bc004004-/-. However, behavioural changes were observed only in bc004004-/- mice after being exposed to CUMS for 21 days, but not in bc004004+/+ after 21-day CUMS exposure, indicating that lack of BRAP homologous protein may cause vulnerability to stress-related disorders in mice. In addition, bc004004-/- mice showed a reduction in recognition memory as revealed by novel object recognition test. Since memory changes and stress related behavioural changes are all closely related to the hippocampus function we further analyzed the changes of dendrites and synapses of hippocampal neurons as well as expression levels of some proteins closely related to synaptic function. bc004004-/- mice exhibited decreased dendritic lengths and increased amount of immature spines, as well as altered expression pattern of synaptic related proteins including GluN2A, synaptophysin and BDNF in the hippocampus. Those findings suggest that BRAP homologous protein may have a protective effect on the behavioural response to stress via regulating dendritic spine formation and synaptic plasticity in the hippocampus.

Clostridioides difficile (C. difficile) is a Gram-positive, spore-forming, toxin-producing, obligate anaerobic bacterium. C. difficile infection (CDI) is the leading cause of healthcare-associated infective diarrhoea. The infection is mediated by the spore, a metabolically inactive form of C. difficile. The spore coat acts as a physical barrier to defend against chemical insults from hosts and natural environments. The composition of spore coat has already been revealed; therefore, the interactive networks of spore coat proteins and the dynamic process of coat assembly are the keys to design strategies to control and cure CDI. This review gives a brief discussion of the signal processing and transcriptional regulation of C. difficile sporulation initiation. Following the discussion, the spore formation is also introduced. Finally, this review mainly focuses on the spore coat assembly, a poorly understood process in C. difficile, and important proteins that have been studied.

Abstract Toxin B (TcdB) is a major exotoxin responsible for diseases associated with Clostridioides difficile infection. Its sequence variations among clinical isolates may contribute to the difficulty in developing effective therapeutics. Here, we investigate receptor-binding specificity of major TcdB subtypes (TcdB1 to TcdB12). We find that representative members of subtypes 2, 4, 7, 10, 11, and 12 do not recognize the established host receptor, frizzled proteins (FZDs). Using a genome-wide CRISPR-Cas9-mediated screen, we identify tissue factor pathway inhibitor (TFPI) as a host receptor for TcdB4. TFPI is recognized by a region in TcdB4 that is homologous to the FZD-binding site in TcdB1. Analysis of 206 TcdB variant sequences reveals a set of six residues within this receptor-binding site that defines a TFPI binding-associated haplotype (designated B4/B7) that is present in all TcdB4 members, a subset of TcdB7, and one member of TcdB2. Intragenic micro-recombination (IR) events have occurred around this receptor-binding region in TcdB7 and TcdB2 members, resulting in either TFPI- or FZD-binding capabilities. Introduction of B4/B7-haplotype residues into TcdB1 enables dual recognition of TFPI and FZDs. Finally, TcdB10 also recognizes TFPI, although it does not belong to the B4/B7 haplotype, and shows species selectivity: it recognizes TFPI of chicken and to a lesser degree mouse, but not human, dog, or cattle versions. These findings identify TFPI as a TcdB receptor and reveal IR-driven changes on receptor-specificity among TcdB variants.

The real-time transmission of ship status data from vessels to shore is crucial for live status monitoring and guidance. Traditional reliance on expensive maritime satellite systems for this purpose is being reconsidered with the emergence of the global short message communication service offered by the BeiDou-3 navigation satellite system. While this system presents a more cost-effective solution, its bandwidth is notably insufficient for handling real-time ship status data. This inadequacy necessitates the compression of such data. Therefore, this paper introduces an algorithm tailored for real-time compression of sequential ship status data. The algorithm is engineered to ensure both accuracy and the preservation of valid data range integrity. Our methodology integrates quantization, predictive coding employing an attention-averaging-based predictor, and arithmetic coding. This combined approach facilitates the transmission of succinct messages through the BeiDou Navigation System, enabling the live monitoring of ocean-going vessels. Experimental trials conducted with authentic data obtained from ship monitoring systems validate the efficiency of our approach. The achieved compression rates closely approximate theoretical minimum values. Consequently, this method exhibits substantial promise for the real-time transmission of parameters across various systems.

The strong survival ability of Salmonella in low-moisture foods (LMFs) has been of public concern, and is considered a threat to people’s health. Recently, the development of omics technology has promoted research on the molecular mechanisms of the desiccation stress response of pathogenic bacteria. However, multiple analytical aspects related to their physiological characteristics remain unclear. We explored the physiological metabolism changes of S. enterica Enteritidis exposed to a 24 h-desiccation treatment and a subsequent 3-month desiccation storage in skimmed milk powder (SMP) with an approach of gas chromatography–mass spectrometry (GC–MS) and ultra-performance liquid chromatography-Q Exactive-mass spectrometry (UPLC-QE-MS). A total of 8,292 peaks were extracted, of which 381 were detected by GC–MS and 7,911 peaks were identified by LC–MS/MS, respectively. Through analyses of differentially expressed metabolites (DEMs) and key pathways, a total of 58 DEMs emerged from the 24 h-desiccation treatment, which exhibited the highest relevance for five metabolic pathways, involving glycine, serine, and threonine metabolism, pyrimidine metabolism, purine metabolism, vitamin B6 metabolism, and pentose phosphate pathway. After 3-month SMP storage, 120 DEMs were identified, which were related to several regulatory pathways including arginine and proline metabolism, serine and threonine metabolism, β-alanine metabolism, glycerolipid metabolism, and glycolysis. The analyses of key enzyme activities of XOD, PK, and G6PDH and ATP content provided further evidence that supported the metabolic responses such as nucleic acid degradation, glycolysis, and ATP production played an important role in Salmonella’s adaptation to desiccation stress. This study enables a better understanding of metabolomics-based responses of Salmonella at the initial stage of desiccation stress and the following long-term adaptive stage. Meanwhile, the identified discriminative metabolic pathways may serve as potentially useful targets in developing strategies for the control and prevention of desiccation-adapted Salmonella in LMFs.

Multi-cluster horizontal well fracturing is one of the key technologies to develop the unconventional reservoirs such as shales. However, the field data shows that some perforation clusters have little production contribution. In this study, a three-dimensional (3D) numerical model for simulating the multiple fracture propagation based on 3D block discrete element method was established, and this model considers the stress interference, perforation friction and fluid-mechanical coupling effect. In order to determine the most appropriate measures to improve the uniformity of multiple fracture propagation, the effect of the geologic and engineering parameters on the multiple fracture propagation in shale reservoirs is investigated. The modeling results show that the geometry of each fracture within a stage is different, and the outer fractures generally receive more fracturing fluid than the interior fractures. The vertical stress almost has no effect on the geometries of multiple fractures. However, higher horizontal stress difference, larger cluster spacing, smaller perforation number, higher injection rate, and smaller fracturing fluid viscosity are conducive to promote the uniform propagation of multiple fractures. The existence of bedding planes will increase the fluid filtration, resulting in a reduction in fracture length. The middle two fractures receive less fluid and the width of them is smaller. Through analyzing the numerical results, a large amount of fracturing fluid should be injected and the proppant with smaller size is suggested to be used to effectively prop the bedding planes. Cluster spacing and perforation number should be controlled in an appropriate range according to reservoir properties. Increasing the injection rate and reducing the viscosity of fracturing fluid are important means to improve the geometry of each fracture.

IntroductionCarbapenemase-producing Enterobacteriales (CPE) are a major health threat worldwide, and therefore the development of rapid detection methods is needed. Here, we established a method to distinguish metallo-β-lactamase and serine carbapenemases using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with ethylenediaminetetraacetic acid (EDTA) and phenylboronic acid (PB).MethodsTo assess the specificity and sensitivity of the method, 110 carbapenemase-producing and 72 carbapenemase-negative Enterobacteriales isolates were collected, among which 51 strains produced only metallo-β-lactamase, 55 strains only serine carbapenemases, and four strains both metallo-β-lactamase and serine carbapenemases. In the proposed MALDI-TOF MS method, imipenem (IPM) and the bacterial strains to be tested were mixed, EDTA and/or PB was added, and the mixture was incubated for 4 h. The carbapenemase type was confirmed by the IPM waveform spectrum before and after incubation.ResultsBased on the presence, absence, and recovery of the IPM-cyano-4-hydroxy-cinnamic acid-specific waveform peak near 479 m/z, the detection sensitivity and specificity of the method were 98.2 and 100%, respectively.DiscussionAlthough CPE detection by MALDI-TOF MS has been studied previously, our method distinguishes between metallo-β-lactamase and serine carbapenemases, which will be very helpful for the clinical selection of antibiotics.

Acid fracturing is an important means of reservoir stimulation, whose purpose is to form an incompletely closed acid-etched fracture as the flow channel for oil and gas during production. The length and conductivity of acid-etched fractures can be used to evaluate acid fracturing and directly impact production. To study their influence on the stimulation effect and final production, an acid fracturing coupling model including a fracture propagation model coupled with reservoir flow and temperature field models is established for the first time in this study based on an embedded discrete fracture model (EDFM), which can realize the coupling of fracture propagation and reservoir flow and simplify the solution of fracture and reservoir temperatures. The simulation results of the acid fracturing coupling model are introduced into the productivity model, which is also based on the EDFM to analyze and evaluate well productivity. The results show that: (1) the EDFM can easily couple fracture propagation and reservoir flow and can be used to rapidly solve the temperature fields in the fracture and reservoir successfully for the first time. (2) Reservoir flow impacts the propagation of fractures by increasing or decreasing the leak-off velocity of the working fluid. (3) Temperature diffusion is much weaker than pressure diffusion during acid fracturing and is limited near the acid fracture. The reaction between the acid and rock increases the local temperature around the acid fracture, and may even exceed the initial formation temperature. (4) Raising the injection rate reasonably enhances H+ diffusion, increases the effective length of acid-etched fractures, enlarges the drainage area of oil and gas, and benefits long-term well production.

Tight sandstone gas reservoir of Shaximiao formation in Jinqiu Gas field has the advantages of wide distribution and abundant resources. Due to its low porosity, low permeability and strong spatial heterogeneity, this reservoir puts forward high requirements for sweet spot identification, cluster design and hydraulic fracture morphology prediction. Since the conventional stimulation methods can not meet the requirement of economy, the geological-engineering integration model is established. This optimization model of multiple subjects could layout the relationship among engineering characteristics, hydraulic fracture shape and well productivity. Based on the simulation results, key controlling factors are identified and optimized. And the customized stimulation strategies are recommended for different reservoir quality and different channel sand. Through application of these methods, the average test well productivity in the target field increased from 50,500 cubic meter per day to 434,300 cubic meter per day, and it lay a solid foundation for the efficient development of tight gas in central Sichuan Basin.

Forest carbon and nitrogen storage significantly affect forest ecosystems and global carbon and nitrogen cycles. Forest management can achieve sustainable development by regulating stand structure. Therefore, the relationship between stand structure and soil carbon (SOCD) and nitrogen storage (SOND) needs in depth study. In this study, experiments were carried out in mixed and pure Pinus massoniana forests to analyze the effects of stand density, stand age, and their interaction on the change trends in SOCD and SOND in different soil layers. The results showed that, in upper (0–20 cm), middle (20–40 cm), and lower (40–60 cm) soil layers, with increased stand density, the SOCD of pure P. massoniana stands first increased and then decreased, while SOND increased monotonically; in mixed P. massoniana stands, SOCD and SOND both increased monotonically. In different development stages (young, middle-aged, and near-mature), the average SOCD of pure P. massoniana stands were 91.31, 88.56, and 85.98 t/ha, respectively, while the average SOCD of mixed P. massoniana stands were 55.92, 48.61, and 55.05 t/ha. The SOCD of pure P. massoniana stands was significantly higher than mixed P. massoniana stands at all growth and development stages. In pure P. massoniana stands, with increasing stand density, the SOCD of young, middle-aged, and near-mature stands first increased and then decreased, while the SOND increased monotonically. In the mixed P. massoniana stands, with increasing stand density, the SOCD of young, middle-aged, and near-mature stands increased monotonically, while the SOND of young stands increased initially and then decreased, while those of middle-aged and near-mature stands increased monotonically. These results emphasized that the artificial regulation of stand density at the appropriate development stage can maximize the carbon and nitrogen fixation potential of forest soil.

In order to solve the difficulties in the volume fracturing stimulation of Middle Jurassic Shaximiao Formation tight sandstone reservoirs in the Qiulin Block of Central Sichuan Basin and explore the adaptability of high-intensity volume fracturing technology, we selected the outcrop samples of Shaximiao Formation tight sandstone in the Qiulin Block to carry out the physical simulation experiment of true triaxial hydraulic fracturing. On this basis, horizontal well cluster perforation was optimally designed by using the production prediction model of staged multi-cluster fracturing horizontal wells. Then, based on the liquid control and proppant increase mode, three rounds of pilot tests were carried out on the tight sandstone reservoirs in this area. And the following research results were obtained. First, natural fractures in the Shaximiao Formation tight sandstone reservoir of the Qiulin Block are undeveloped, and hydraulic fractures are morphologically dominated by symmetric double-wing fractures, so complex fracture networks can be hardly formed. In addition, the reservoir is of medium to strong water sensitivity, so conventional volume fracturing is not adaptive to the reservoir stimulation in this block. Second, the connotation of high-intensity volume fracturing technology is to carry out multi-cluster perforation in each section to form multiple independent double-wing fractures and to implement the proppant injection mode of liquid control and proppant increase to reduce the inflow fluid while ensuring the high-intensity proppant injection, so as to reduce the damage of inflow fluid to the formation. Third, there are 10 fracturing sections in Well Qiulin 207-5-H2, with 7–12 clusters in each section, and the displacement is in the range of 16–18 m3/min. According to the fluid control and proppant increase mode, 12146 m3 slick water and 4170 t proppant are injected in total. The tested production rate and absolute open flow of natural gas after the fracturing are up to 83.88 × 104 m3/d and 214.05 × 104 m3/d, respectively. Fourth, with the decrease of cluster spacing, the cumulative gas production increases gradually, but when the cluster spacing is less than 15 m, the increase amplitude of cumulative gas production decreases. Fifth, when the proppant injection intensity is lower than 6 t/m, the tested gas production per kilometer of stimulated section in a horizontal well overall presents an increasing trend with the increase of proppant injection intensity. When the proppant injection intensity is higher than 6 t/m, however, the tested gas production per kilometer of stimulated section does not increase significantly with the increase of proppant injection intensity. Sixth, as the included angle between the borehole trajectory and the direction of maximum horizontal principal stress increases, the tested gas production per kilometer of stimulated section overall presents an increasing trend. When the hydraulic fracture is nearly perpendicular to the borehole, the effective drainage area is the largest and the tested gas production per kilometer of stimulated section is also the highest. In conclusion, the fracturing mode of high production well has a borehole trajectory of large included angle, perforation cluster spacing of 10 m or so, proppant injection intensity of 5 t/m and large-displacement slick water + continuous injection of combined particle size proppant.

Hypothalamus-pituitary-adrenal (HPA) axis plays critical roles in stress responses under challenging conditions such as hypoxia, via regulating gene expression and integrating activities of hypothalamus-pituitary-targets cells. However, the transcriptional regulatory mechanisms and signaling pathways of hypoxic stress in the pituitary remain to be defined. Here, we report that hypoxia induced dynamic changes in the transcription factors, hormones, and their receptors in the adult rat pituitary. Hypoxia-inducible factors (HIFs), oxidative phosphorylation, and cAMP signaling pathways were all differentially enriched in genes induced by hypoxic stress. In the pituitary gene network, hypoxia activated c-Fos and HIFs with specific pituitary transcription factors (Prop1), targeting the promoters of hormones and their receptors. HIF and its related signaling pathways can be a promising biomarker during acute or constant hypoxia. Hypoxia stimulated the transcription of marker genes for microglia, chemokines, and cytokine receptors of the inflammatory response. Corticotropin-releasing hormone receptor 1 (CRHR1) mediated the transcription of Pomc, Sstr2, and Hif2a, and regulated the function of HPA axis. Together with HIF, c-Fos initiated and modulated dynamic changes in the transcription of hormones and their receptors. The receptors were also implicated in the regulation of functions of target cells in the pituitary network under hypoxic stress. CRHR1 played an integrative role in the hypothalamus-pituitary-target axes. This study provides new evidence for CRHR1 involved changes of hormones, receptors, signaling molecules and pathways in the pituitary induced by hypoxia.

Chondroitin sulfate proteoglycan 4 (CSPG4) is a potential receptor for C. difficile toxin B (TcdB) during C. difficile infections (CDIs). Here, the cryo-EM structure of a TcdB–CSPG4 complex and CDI mouse models offer insights into CSPG4 role in CDIs and suggest a therapeutic strategy targeting TcdB.

To study the casing deformation (CD) in shale gas well fracturing caused by natural fracture slip, a fracture face stress model is built based on stress analysis, and a CD prediction model is established based on complex function to analyze factors affecting wellbore shear stress and CD. (1) The fracture and wellbore approach angles have significant impacts on the wellbore shear stress. In Weiyuan shale gas field, Sichuan Basin, under the common wellbore approach angle of nearly 90°, the wellbore is subjected to large shear stress and high risk of CD at the fracture approach angle range of 20° to 55° or its supplementary angle range. (2) When the fracture is partially opened, the wellbore shear stress is positively correlated with the fluid pressure, and negatively correlated with the fracture friction coefficient; when the fracture is fully opened, the wellbore shear stress is positively correlated with the natural fracture area. (3) The lower the elastic modulus and the longer the fracture length, the more serious the CD will be, and the Poisson's ratio has a weak influence on the CD. The deformation first increases and then decreases with the increase of fracture approach angle, and reaches the maximum when the fracture approach angle is 45°. (4) At a given fracture approach angle, appropriately adjusting the wellbore approach angle can avoid high shear stress acting on wellbore, and reasonable control of the fluid pressure in the fracture can reduce the CD risk. The shear stress acting on casing is usually much greater than the shear strength of casing, so increasing casing strength or cementing quality have limited effect on reducing the risk of CD. Caliper logging data has verified that the CD prediction model is reliable, so the model can be used to establish risk analysis chart and calculate deformation value, to provide a reference for quick CD risk prediction in fracturing design.

Background Short-term dynamic changes in neutralizing antibodies against EV71 and EV71-IgM after inactivated EV71 vaccine injection are unknown. Methods This study was designed as a randomized, open-label study and was registered at ClinicalTrials.gov (NCT03278132). In total, 120 healthy infants aged 6–35 months were randomized 1:1:1 to provide a second blood sample on day 10, day 20, or day 30 after the first vaccine dose, respectively. Results According to the per-protocol set, a rapid immune response against EV71 was observed 10 days after the first EV71 vaccine dose, with antibody titers ≥1:8 in 89.19% of participants (95% CI: 74.58–96.97%) on day 10, in 80.65% (95% CI: 62.53–92.55%) on day 20, in 66.67% (95% CI: 49.03–81.44%) on day 30, and in 100% (95% CI: 96.52%-.) on day 60. Based on an ELISA, the percentages of participants positive for EV71-IgM on day 0 and day 60 were 1.71% (2 out of 117) and 82.86% (87 out of 105), respectively. Conclusions The EV71 vaccine could be used for contingency vaccination to further control EV71-associated disease outbreaks. Caution should be taken in using the EV71-IgM test for rapid EV71 infection diagnosis after EV71 vaccine administration. Clinical Trial Registration ClinicalTrials.gov NCT03278132

Hydraulic fracturing is an important technology for the stimulation of oil and gas reservoirs. Conventional fracturing technology based on “sand-carrying” faces some challenges such as sand plugs; incompatibility with the well completion method; damage to the reservoir caused by the incomplete gel-breaking of the fracturing fluid; solid proppants inefficiently turning the corner in complex fracture networks, and so on. In this paper, a novel self-generated proppant fracturing fluid system is proposed to solve the above problems caused by “sand-carrying”. The advantage of the fracturing fluid system is that in the whole process of fracturing, no solid proppants will be injected. The fracturing fluid itself will transform into solid proppants in the induced fractures under high temperatures to resist fracture closure stress. The fluid system consists of two kinds of liquids. One is the phase change liquid (PCL), which occurs as a liquid–solid phase change at high-formation temperatures to form a solid proppant. The other is the non-phase change liquid (NPCL), which controls the dispersity of the PCL in the two-phase fluid system. The main building block of the PCL is confirmed to be the bisphenol-A diglycidyl ether-type epoxy resin, whereas the NPCL is mainly composed of surfactants. The viscosity, phase-change temperature, and time of the fracturing fluid system are, respectively, about 30 mPa·s, 80 °C, and 20 min.

Abstract Background Infections by Streptococcus gallolyticus subsp. pasteurianus (SGSP) is often underestimated. Herein, the epidemiological features and resistant characteristics of SGSP in mainland China are characterized to enable a better understanding of its role in clinical infections. Methods In the present work, 45 SGSP isolates were collected from the samples of bloodstream, urine, aseptic body fluid, and fetal membrane/placenta from patients in 8 tertiary general hospitals of 6 cities/provinces in China from 2011 to 2017. The identification of all isolates was performed using traditional biochemical methods, 16S rRNA and gyrB sequencing, followed by the characterization of their antibiotic resistance profiling and involved genes. Results Among 34 non-pregnancy-related patients, 4 (4/34,11.8%) patients had gastrointestinal cancer, 10 (10/34, 29.4%) patients had diabetes, and one patient had infective endocarditis. Moreover, 11 cases of pregnant women were associated with intrauterine infection (9/11, 81.2%) and urinary tract infection (1/11, 9.1%), respectively. Except one, all other SGSP isolates were correctly identified by the BD Phoenix automated system. We found that all SGSP isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, meropenem, and vancomycin. Forty strains (40/45, 88.9%) were both erythromycin and clindamycin-resistant, belonging to the cMLSB phenotype, and the majority of them carried erm(B) gene (39/40, 97.5%). Although the cMLSB/erm(B) constituted the most frequently identified phenotype/genotype combination (25/40, 62.5%) among all erythromycin-resistant cMLSB isolates, erm(B)/erm(A), erm(B)/mef(A/E), and erm(B)/erm(T) was detected in 7, 4, and 3 isolates, respectively. Furthermore, 43 strains (43/45, 95.6%) were tetracycline-resistant, and out of these, 39 strains (39/45, 86.7%) carried tet(L), 27(27/45, 60.0%) strains carried tet(O), and 7 (7/45, 15.6%) strains carried tet(M), alone or combined, respectively. All erythromycin-resistant isolates were also resistant to tetracycline. Conclusions It is important to study and draw attention on SGSP, an underreported opportunistic pathogen targeting immunodeficient populations, notably elderly subjects, pregnant women and neonates.

The study was to evaluate the safety, immunogenicity and lot-to-lot consistency of live attenuated varicella vaccine in Chinese population aged 1–3 years. The double-blind, randomized phase III trial was conducted in Henan Province, China. In total, 1197 subjects were included in this study. Subjects were randomly assigned into four groups in a 2:2:2:1 ratio to receive one of the three lots of commercial scale (CS) vaccine or the licensed pilot scale (LPS) vaccine. Seroconversion rate and neutralizing antibody titers (NATb) were assessed at day 0 pre-vaccination and at day 30 post-vaccination. Safety data were recorded for 30 days post-vaccination. After vaccination, the geometric mean titers (GMTs) of the three CS groups were 25.04 (95% confidence interval [CI], 22.85 to 27.44), 24.47 (95% CI, 22.35 to 26.78) and 25.88 (95% CI, 23.61 to 28.36), respectively (P= 0.6928). The ratio of GMTs adjusted for covariates of each pair of lots were all between 0.67 to 1.50 in susceptible subjects. The difference of seroconversion rate between pooled CS group and LPS group was 3.82 (95% CI, 0.55 to 8.81). Meanwhile, the percentage of solicited local, systemic and unsolicited adverse reactions showed no difference across the four groups, and most of the adverse reactions were mild or moderate in intensity. The CS group was comparable to the LPS group in safety and immunogenicity. The consistency of three consecutive CS lots was reliable. Moreover, the CS group was non-inferior to the LPS group.

Abstract Background Many regions in the world are experiencing changes in precipitation pattern, which likely impact soil nitrogen cycling and availability. However, we know little about how soil nitrogen processes respond to drought stress under climate change. Methods A continuous 5-year experiment of throughfall reduction treatment (TRT) was conducted in a Castanopsis hystrix plantation in subtropical China to assess how soil nitrogen processes responded to a change in precipitation. Net nitrogen transformation, soil properties, microbial biomass carbon (MBC) and nitrogen (MBN), and microbial community phospholipid fatty acids (PLFAs as bacteria, fungi and arbuscular mycorrhizal fungi (AMF)) were investigated in the wet and dry seasons over the period of the manipulation experiment. Results TRT had no significant effects on net ammonification rate (NAR) and nitrogen mineralization rate (NMR), and the unchanged NAR and NMR were mainly caused by the no change of soil nitrogen availability (i.e. NH4 +-N, NO3 −-N and dissolved organic nitrogen). However, TRT significantly increased net nitrification rate (NNR) in the wet season primarily due to the increase in NO3 − concentration, and might be further caused by reduced NO3 − leaching, denitrification or NO3 −-N uptake in the TRT. Differently, TRT significantly decreased the NNR in the dry season, which might be linked to the limited SWC that resulted in greater microbial nitrate immobilization than gross nitrate mineralization. In addition, TRT significantly influenced the soil microbial community composition in 0–10 cm soil layer in the wet season, primarily due to the variations in NO3 −-N, DOC and DON. Conclusions Precipitation reduction affected the NNR rather than NAR and NMR, and consequently, further affected soil N availability and N uptake by Castanopsis hystrix.

Listeriosis, caused by Listeria monocytogenes, is a severe food-borne infection. The nationwide surveillance in China concerning listeriosis is urgently needed. In the present study, 144 L. monocytogenes isolates were collected from the samples of blood, cerebrospinal fluid (CSF), and fetal membrane/placenta in China for 12 years from 2008 to 2019. We summarized these listeriosis patients’ demographical and clinical features and outcomes. The susceptibility profile for 12 antibiotics was also determined by the broth microdilution method. Multilocus sequence typing (MLST) and serogroups of these listeria isolates were analyzed to designate epidemiological types. We enrolled 144 cases from 29 healthcare centers, including 96 maternal-neonatal infections, 33 cases of bacteremia, 13 cases of neurolisteriosis, and two cutaneous listeriosis. There were 31 (59.6%) fetal loss in 52 pregnant women and four (9.8%) neonatal death in 41 newborns. Among the 48 nonmaternal-neonatal cases, 12.5% (6/48) died, 41.7% (20/48) were female, and 64.6% (31/48) occurred in those with significant comorbidities. By MLST, the strains were distinguished into 23 individual sequence types (STs). The most prevalent ST was ST87 (49 isolates, 34.0%), followed by ST1 (18, 12.5%), ST8 (10, 6.9%), ST619 (9, 6.3%), ST7 (7, 4.9%) and ST3 (7, 4.9%). Furthermore, all L. monocytogenes isolates were uniformly susceptible to penicillin, ampicillin, and meropenem. In summary, our study highlights a high genotypic diversity of L. monocytogenes strains causing clinical listeriosis in China. Furthermore, a high prevalence of ST87 and ST1 in the listeriosis should be noted.

Clostridioides difficile is the major worldwide cause of antibiotic-associated gastrointestinal infection. A pathogenicity locus (PaLoc) encoding one or two homologous toxins, toxin A (TcdA) and toxin B (TcdB), is essential for C. difficile pathogenicity. However, toxin sequence variation poses major challenges for the development of diagnostic assays, therapeutics, and vaccines. Here, we present a comprehensive phylogenomic analysis of 8,839 C. difficile strains and their toxins including 6,492 genomes that we assembled from the NCBI short read archive. A total of 5,175 tcdA and 8,022 tcdB genes clustered into 7 (A1-A7) and 12 (B1-B12) distinct subtypes, which form the basis of a new method for toxin-based subtyping of C. difficile. We developed a haplotype coloring algorithm to visualize amino acid variation across all toxin sequences, which revealed that TcdB has diversified through extensive homologous recombination throughout its entire sequence, and formed new subtypes through distinct recombination events. In contrast, TcdA varies mainly in the number of repeats in its C-terminal repetitive region, suggesting that recombination-mediated diversification of TcdB provides a selective advantage in C. difficile evolution. The application of toxin subtyping is then validated by classifying 351 C. difficile clinical isolates from Brigham and Women's Hospital in Boston, demonstrating its clinical utility. Subtyping partitions TcdB into binary functional and antigenic groups generated by intragenic recombinations, including two distinct cell-rounding phenotypes, whether recognizing frizzled proteins as receptors, and whether it can be efficiently neutralized by monoclonal antibody bezlotoxumab, the only FDA-approved therapeutic antibody. Our analysis also identifies eight universally conserved surface patches across the TcdB structure, representing ideal targets for developing broad-spectrum therapeutics. Finally, we established an open online database (DiffBase) as a central hub for collection and classification of C. difficile toxins, which will help clinicians decide on therapeutic strategies targeting specific toxin variants, and allow researchers to monitor the ongoing evolution and diversification of C. difficile.

Close-to-nature transformation silviculture is a promising approach to meet the criteria for sustainable forestry. To explore the effects of close-to-nature transformation on community structure and plant diversity in Pinus massoniana and Cunninghamia lanceolatas pure plantations, four stands were selected, including close-to-nature transformed stand of P. massoniana (PCN) and its unimproved pure stand (PCK), and close-to-nature transformed stand of C. lanceolata (CCN) and its unimproved pure stand (CCK). Plant diversity and community structure in the four stands were investigated before and after a decade of close-to-nature transformation. After the close-to-nature transformation, the plant diversity and community structure were significantly altered. Compared with control stands, the transformation increased the species richness and diversity of the tree layer and the whole community, while did not significantly affected the shrub and herb diversity. The species richness in the tree layer in the P.massoniana and C.lanceolata plantations was 2.1 and 2.8 times that of their corresponding control. Species composition and important value of each species were altered in the tree, shrub and herb layers. The close-to-natural transformation lowered the community dominance and the important value of P. massoniana and C. lanceolate. The advantage position of single species in the community was weakened by the forest transformation. The plant community became diversified and uniformly distributed. The enhanced community species diversity was derived from the increase in the tree diversity. These results indicated that close-to-nature transformation increased the forest plant diversity and optimized the community structure. The close-to-nature transformation plays a positive role in coniferous plantation ecosystem structure.

BackgroundBeijing is a national and international hub potentially containing a broad diversity of HIV variants. Previous studies on molecular epidemiology of HIV in Beijing pooled together samples from residents and non-residents. Pooling residents and non-residents has potentially introduced bias and undermined a good assessment and the intervention among the autochthonous population. Here, we aimed to define HIV subtype diversity and investigate the TDR in Beijing residents exclusively.MethodsWe analyzed the demographic, clinical, and virological data collected between 2001 and 2016 from residents in Beijing. A population-based sequencing of the HIV pol gene was carried out using plasma specimens. Phylogenetic analysis was performed in order to classify sequences into their corresponding subtypes using an automated subtyping tool, the Context-Based Modeling for Expeditious Typing (COMET). Furthermore, the drug resistance mutations were determined using the World Health Organization list for surveillance of TDR mutations.ResultsData on TDR were available for 92% of 2,315 individuals with HIV infection, of whom 7.1% were women. The bioinformatic analysis of HIV strains from this study revealed that a combined 17 subtypes were circulating in Beijing, China between 2001 and 2016. The most common ones were CRF01_AE, CRF07_BC, and subtype B in Beijing during this period. The overall prevalence of TDR was 4.5% (95% confidence intervals[CI]: 3.6%-5.4%), with a declining trend over the period of spanning 2001 through 2016. In-depth class-specific analysis revealed that the prevalence of TDR for the nucleoside reverse-transcriptase inhibitors (NRTIs) was 1.0% (95% CI: 0.6-1.5), 0.9% (95% CI:0.6-1.4) for non-NRTIs and 2.8% (95% CI:2.1-3.5) for protease inhibitors. The prevalence of TDR was lower in individuals infected with the CRF07_BC HIV strain than those infected with CRF01_AE.ConclusionsOur data showed that the HIV epidemic in Beijing displayed a high genetic heterogeneity and a low and declining prevalence of TDR. In sharp contrast to Europe and North America, the declining trend of TDR between 2001 through 2016 was noticed while there was a widespread distribution of antiretroviral treatment in Beijing, China.

Abstract Background Streptococcus pneumoniae, the leading pathogen of bacterial infections in infants and the elderly, is responsible for pneumococcal diseases with severe morbidity and mortality. Emergence of drug-resistant strains presented new challenges for treatment and prevention. Vaccination has proven to be an effective means of preventing pneumococcal infection worldwide. Detailed epidemiological information of antibiotic susceptibilities and serotype distribution will be of great help to the management of pneumococcal infections. Methods A total of 881 S. pneumoniae isolates were collected from patients at 23 teaching hospitals in 17 different cities from 2011 to 2016. The main specimen types included sputum, blood, broncho-alveolar lavage fluid, pharyngeal swabs, and cerebrospinal fluid. Minimum inhibitory concentrations (MICs) were determined using the agar dilution method. Capsular serotypes were identified using latex agglutination and quellung reaction test. Molecular epidemiology was investigated using multilocus sequence typing. Results S. pneumoniae isolates were highly resistant to macrolides, tetracycline, and trimethoprim/sulfamethoxazole. The rate of resistance to penicillin was 51.6% (oral breakpoint). However, levofloxacin and moxifloxacin maintained excellent antimicrobial activity and all of the isolated strains were susceptible to vancomycin. Twenty-two serotypes were identified among the 881 isolates. Prevalent serotypes were 19F (25.7%), 19A (14.0%), 15 (6.8%), 6B (3.6%), 6A (3.0%), and 17 (2.8%). The overall vaccine coverage rates for 7- and 13-valent pneumococcal conjugate vaccines were 37.5% and 58.3%, respectively. Vaccine coverage rates in young children and economically underdeveloped regions were higher than those in older adults and developed regions. Vaccine-covered serotypes demonstrated higher resistance compared with uncovered serotypes. Molecular epidemiological typing demonstrated that S. pneumoniae showed significant clonal dissemination and that ST271 (120, 28.3%), ST320 (73, 17.2%) and ST81 (27, 6.6%) were the major STs. Conclusions High resistance to clinical routine antibiotics was observed for all 881 S. pneumoniae strains. Drug resistance varied among different serotypes and age groups. Prevalent serotypes among the isolates were 19F, 19A, 15, 6B, 6A, and 17. Community-acquired strains should also be included in future studies to gain a better understanding of the prevalence and resistance of S. pneumoniae in China.

The Lower Permian reservoirs in the western Sichuan Basin are ultra-deep with high temperature, high pressure and developed natural fractures. Leakage and contamination of drilling fluid is the main factor restricting reservoir stimulation effects, so the acidification will be the solution also as the first choice to enhance the gas recovery. In view of this, an acidification design was proposed to minimize the contamination skin factor to the highest degree. A model was first developed to calculate the critical pumping rate for opening natural fractures in deep beds. Then, the acidification model for the rock samples of natural fractures in the experimental scale was modified, and a model was established for predicting the effective penetration distance of acid and the fracture aperture in the conditions of wellbores. Accordingly, a skin factor calculation model for network-fracture acidification was developed. It is indicated that when the acid pumping rate is 5.0 m3/min, all natural fractures around Well S1-1 can be opened, regardless of their dip angles. Besides, the advantage of high-rate acid injection emerges gradually when the injected acid is more than 100 m3. Moreover, for minimizing the skin factor, the network-fracture acidification in Well S1-1 was optimized by pumping 210 m3 acid at the rate of 4.5 m3/min. According to the optimal design idea, network-fracture acidification has been successfully applied in Well S1-1, and a high-yield industrial gas flow was produced at the rate of 83.7 × 104 m3/d. It is concluded that network-fracture acidification technology is a safest, most economical and effective mode for the stimulation of such ultra-deep reservoirs in the study area.

This study aimed to design a new method for rapid and accurate detection of carbapenemase phenotypes based on the simplified carbapenem inactivation method (sCIM). We evaluated the sensitivity and specificity of the method, called the rapid carbapenemase detection method (rCDM), for the detection of carbapenemase-producing Enterobacteriaceae and Pseudomonas aeruginosa. A total of 257 Enterobacteriaceae, 236 P. aeruginosa, and 20 Acinetobacter baumannii isolates were tested. Phenotypic evaluations were performed using rCDM, sCIM, and mCIM. For Enterobacteriaceae, the sensitivity of rCDM was 100% and the specificity was 99.6%. For P. aeruginosa, the sensitivity of rCDM was 97.4% and the specificity was 100%. Carbapenemase-producing A. baumannii were not detected by rCDM. The concordance rate of rCDM and sCIM for Enterobacteriaceae and P. aeruginosa was 99.8%, with the exception of one P. aeruginosa isolate that expressed the blaVIM−4 gene. The concordance rate of rCDM and mCIM for Enterobacteriaceae and P. aeruginosa was 100%. rCDM can be used to accurately detect carbapenemase-producing Enterobacteriaceae and P. aeruginosa in 5–6 h and is suitable for routine use in most clinical microbiology laboratories.

This study reports the simplified carbapenem inactivation method (sCIM) to detect carbapenemase-producing gram-negative bacilli in a simple and accurate manner. This method is based on the modified carbapenem inactivation method (mCIM) with the improvement of experimental procedures. Instead of incubating the antibiotic disk in the organism culture media, the organism to be tested was smeared directly onto the antibiotic disk in the sCIM. For evaluating the sensitivity and specificity of the method, a total of 196 Enterobacteriaceae, 73 Acinetobacter baumannii, and 158 Pseudomonas aeruginosa isolates were collected. Polymerase chain reaction (PCR) was used to detect the carbapenemase genes. Phenotypic evaluations were performed using both the sCIM and the mCIM. PCR results showed that, of the 196 Enterobacteriaceae strains, 147 expressed the carbapenemase genes blaKPC−2 (58.5%), blaIMP−4 (21.8%), blaIMP−2 (2.0%), blaVIM−1 (6.1%), blaNDM−1 (10.2%), and blaOXA−48 (1.4%). sCIM results had high concordance with PCR results (99.5%) and mCIM results (100%) with the exception of one Klebsiella pneumoniae strain, which had an minimal inhibitory concentration (MIC) for imipenem of 0.25 mg/L. PCR demonstrated that 53 of the 73 A. baumannii isolates expressed the carbapenemase genes blaOXA−23 (98.1%) and blaVIM−2 (1.8%). sCIM and PCR results corresponded but all A. baumannii isolates were carbapenemase negative by the mCIM. PCR demonstrated that 25 of the 158 P. aeruginosa isolates expressed carbapenemase genes blaVIM−1 (52%), blaVIM−2 (8%), blaVIM−4 (36%), and blaIMP−4 (4%). sCIM results had high concordance with PCR results (100%) and the mCIM results (99.4%) with the exception of one P. aeruginosa isolate that expressed the blaVIM−4 gene. The sCIM offers specificity and sensitivity comparable to PCR but has the advantage of being more user-friendly. This method is suitable for routine use in most clinical microbiology laboratories for the detection of carbapenemase-producing gram-negative bacilli.

Streptococcus pyogenes, or group A Streptococcus, is a pathogen responsible for a wide range of clinical manifestations, from mild skin and soft tissue infections and pharyngitis to severe diseases. Its epidemiological characteristics should be comprehensively under surveillance for regulating the national prevention and treatment practice. Herein, a total of 140 S. pyogenes, including 38 invasive and 102 noninvasive isolates, were collected from infected patients in 10 tertiary general hospitals from 7 cities/provinces in China during the years 2009–2016. All strains were characterized by classical and molecular techniques for its emm types/subtypes, virulent factors and antibiotic resistance profiling. Of 140 isolates, 15 distinct emm types and 31 subtypes were detected, dominated by emm12 (60 isolates, 42.9%), emm1(43, 30.7%), and emm89 (10, 7.1%), and 8 new emm variant subtypes were identified. All strains, invasive or not, harbored the superantigenic genes, speB and slo. The other virulence genes, smeZ, speF, and speC accounted for 96.4, 91.4, and 87.1% of collected isolates, respectively. Further multilocus sequence typing (MLST) placed all strains into 22 individual sequence types (STs), including 4 newly-identified STs (11, 7.9%). All isolates were phenotypically susceptible to penicillin, ampicillin, cefotaxime, and vancomycin, whereas 131(93.5%), 132(94.2%), and 121(86.4%) were resistant to erythromycin, clindamycin, and tetracycline, respectively. Our study highlights high genotypic diversity and high prevalence of macrolide resistance of S. pyogenes among clinical isolates circulating in China.

Synaptic activity increases the resistance of neurons to diverse apoptotic insults; however, the underlying mechanisms remain less well understood. Zinc promotes cell survival under varied conditions, but the role of synaptically released zinc in the activity-dependent anti-apoptotic effect is unknown. Using cultured hippocampal slices and primary neurons we show that a typical apoptosis inducer-staurosporine (STP) was able to cause concentration-dependent apoptotic cell death in brain slices; Enhanced synaptic activity by bicuculline (Bic)/4-Aminopyridine (AP) treatment effectively prevented neurons from STP-induced cell apoptosis, as indicated by increased cell survival and suppressed caspase-3 activity. Application of Ca-EDTA, a cell membrane-impermeable zinc chelator which can efficiently capture the synaptically released zinc, completely blocked the neuronal activity-dependent anti-apoptotic effect. Same results were also observed in cultured primary hippocampal neurons. Therefore, our results indicate that synaptic activity improves neuronal resistance to apoptosis via synaptically released zinc.