White-Emitting Gold Nanocluster Assembly with Dynamic Color Tuning.

We report that constructed Au nanoclusters (NCs) can afford amazing white emission synergistically dictated by the Au(0)-dominated core-state fluorescence and Au(I)-governed surface-state phosphorescence, with record-high absolute quantum yields of 42.1% and 53.6% in the aqueous solution and powder state, respectively. Moreover, the dynamic color tuning is achieved in a wide warm-to-cold white-light range (with the correlated color temperature varied from 3426 to 24 973 K) by elaborately manipulating the ratio of Au(0) to Au(I) species and thus the electron transfer rate from staple motif to metal kernel. This study not only exemplifies the successful integration of multiple luminescent centers into metal NCs to accomplish efficient white-light emission but also inspires a feasible pathway toward customizing the optical properties of metal NCs by regulating electron transfer kinetics.

High accuracy model for HBsAg loss based on longitudinal trajectories of serum qHBsAg throughout long-term antiviral therapy.

OBJECTIVE: Hepatitis B surface antigen (HBsAg) loss is the optimal outcome for patients with chronic hepatitis B (CHB) but this rarely occurs with currently approved therapies. We aimed to develop and validate a prognostic model for HBsAg loss on treatment using longitudinal data from a large, prospectively followed, nationwide cohort. DESIGN: CHB patients receiving nucleos(t)ide analogues as antiviral treatment were enrolled from 50 centres in China. Quantitative HBsAg (qHBsAg) testing was prospectively performed biannually per protocol. Longitudinal discriminant analysis algorithm was used to estimate the incidence of HBsAg loss, by integrating clinical data of each patient collected during follow-up. RESULTS: In total, 6792 CHB patients who had initiated antiviral treatment 41.3 (IQR 7.6-107.6) months before enrolment and had median qHBsAg 2.9 (IQR 2.3-3.3) log10IU/mL at entry were analysed. With a median follow-up of 65.6 (IQR 51.5-84.7) months, the 5-year cumulative incidence of HBsAg loss was 2.4%. A prediction model integrating all qHBsAg values of each patient during follow-up, designated GOLDEN model, was developed and validated. The AUCs of GOLDEN model were 0.981 (95% CI 0.974 to 0.987) and 0.979 (95% CI 0.974 to 0.983) in the training and external validation sets, respectively, and were significantly better than those of a single qHBsAg measurement. GOLDEN model identified 8.5%-10.4% of patients with a high probability of HBsAg loss (5-year cumulative incidence: 17.0%-29.1%) and was able to exclude 89.6%-91.5% of patients whose incidence of HBsAg loss is 0. Moreover, the GOLDEN model consistently showed excellent performance among various subgroups. CONCLUSION: The novel GOLDEN model, based on longitudinal qHBsAg data, accurately predicts HBsAg clearance, provides reliable estimates of functional hepatitis B virus (HBV) cure and may have the potential to stratify different subsets of patients for novel anti-HBV therapies.

Enzyme-Inspired Ligand Engineering of Gold Nanoclusters for Electrocatalytic Microenvironment Manipulation.

Natural enzymes intricately regulate substrate accessibility through specific amino acid sequences and folded structures at their active sites. Achieving such precise control over the microenvironment has proven to be challenging in nanocatalysis, especially in the realm of ligand-stabilized metal nanoparticles. Here, we use atomically precise metal nanoclusters (NCs) as model catalysts to demonstrate an effective ligand engineering strategy to control the local concentration of CO2 on the surface of gold (Au) NCs during electrocatalytic CO2 reduction reactions (CO2RR). The precise incorporation of two 2-thiouracil-5-carboxylic acid (TCA) ligands within the pocket-like cavity of [Au25(pMBA)18]- NCs (pMBA = para-mercaptobenzoic acid) leads to a substantial acceleration in the reaction kinetics of CO2RR. This enhancement is attributed to a more favorable microenvironment in proximity to the active site for CO2, facilitated by supramolecular interactions between the nucleophilic Nδ- of the pyrimidine ring of the TCA ligand and the electrophilic Cδ+ of CO2. A comprehensive investigation employing absorption spectroscopy, mass spectrometry, isotopic labeling measurements, electrochemical analyses, and quantum chemical computation highlights the pivotal role of local CO2 enrichment in enhancing the activity and selectivity of TCA-modified Au25 NCs for CO2RR. Notably, a high Faradaic efficiency of 98.6% toward CO has been achieved. The surface engineering approach and catalytic fundamentals elucidated in this study provide a systematic foundation for the molecular-level design of metal-based electrocatalysts.

Unraveling a Concerted Proton-Coupled Electron Transfer Pathway in Atomically Precise Gold Nanoclusters.

Metal nanoclusters (MNCs) represent a promising class of materials for catalytic carbon dioxide and proton reduction as well as dihydrogen oxidation. In such reactions, multiple proton-coupled electron transfer (PCET) processes are typically involved, and the current understanding of PCET mechanisms in MNCs has primarily focused on the sequential transfer mode. However, a concerted transfer pathway, i.e., concerted electron-proton transfer (CEPT), despite its potential for a higher catalytic rate and lower reaction barrier, still lacks comprehensive elucidation. Herein, we introduce an experimental paradigm to test the feasibility of the CEPT process in MNCs, by employing Au18(SR)14 (SR denotes thiolate ligand), Au22(SR)18, and Au25(SR)18- as model clusters. Detailed investigations indicate that the photoinduced PCET reactions in the designed system proceed via an CEPT pathway. Furthermore, the rate constants of gold nanoclusters (AuNCs) have been found to be correlated with both the size of the cluster and the flexibility of the Au-S framework. This newly identified PCET behavior in AuNCs is prominently different from that observed in semiconductor quantum dots and plasmonic metal nanoparticles. Our findings are of crucial importance for unveiling the catalytic mechanisms of quantum-confined metal nanomaterials and for the future rational design of more efficient catalysts.

Role of Early On-Treatment Serum HBV RNA Declines in Predicting Hepatocellular Carcinoma Risk in Patients With Chronic Hepatitis B.

BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) risk prediction models established in patients with chronic hepatitis B receiving a nucleos(t)ide analogue (NA) rarely include viral factors because of mediocre predictability of traditional viral markers. Here, we investigate the role of serum hepatitis B virus (HBV) RNA, a novel biomarker, in predicting HCC risk in NA-treated patients. METHODS: A total of 1374 NA-treated patients were enrolled from 2 prospective chronic hepatitis B cohorts. Serum HBV RNA was detected at baseline, year 1, 2 and 3 of treatment. Cox proportional-hazard model was used to investigate the association of HBV RNA kinetics with HCC risk. RESULTS: After a median follow-up of 5.4 years, 76 patients developed HCC. HBV RNA declines at year 1 (adjusted hazard ratio, 0.70, P = .009) and 2 (adjusted hazard ratio, 0.71; P = .016) were independently associated with HCC risk. Patients with less HBV RNA decline at year 1 (≤0.4 log10 copies/mL) or 2 (≤0.6 log10 copies/mL) had 2.22- and 2.09-folds higher HCC risk, respectively, than those with more declines. When incorporating these early on-treatment HBV RNA declines into existing HCC risk scores, including PAGE-B (age, sex, and platelets), modified PAGE-B (mPAGE-B) (age, sex, platelets, and albumin), and aMAP (age, sex, platelets, and albumin-bilirubin score) score, they could enhance their predictive performance (ie, C-index 0.814 vs 0.78 [model (PAGE-B + year-1 HBV RNA decline) vs PAGE-B score based on baseline parameters]). CONCLUSIONS: Serum HBV RNA declines at year 1 and 2 were significantly associated with on-treatment HCC risk. Incorporating early on-treatment HBV RNA declines into HCC risk prediction models can be useful tools to guide appropriate surveillance strategies in NA-treated patients.

Enhancing Localized Electron Density over Pd1.4Cu Decorated Oxygen Defective TiO2-x Nanoarray for Electrocatalytic Nitrite Reduction to Ammonia.

Electrocatalytic nitrite (NO2 -) reduction to ammonia (NH3) is a promising method for reducing pollution and aiding industrial production. However, progress is limited by the lack of efficient selective catalysts and ambiguous catalytic mechanisms. This study explores the loading of PdCu alloy onto oxygen defective TiO2-x, resulting in a significant increase in NH3 yield (from 70.6 to 366.4 µmol cm-2 h-1 at -0.6 V vs reversible hydrogen electrode) by modulating localized electron density. In situ and operando studies illustrate that the reduction of NO2 - to NH3 involves gradual deoxygenation and hydrogenation. The process also demonstrated excellent selectivity and stability, with long-term durability in cycling and 50 h stability tests. Density functional theory (DFT) calculations elucidate that the introduction of PdCu alloys further amplified electron density at oxygen vacancies (Ovs). Additionally, the Ti─O bond is strengthened as the d-band center of the Ti 3d rising after PdCu loading, facilitating the adsorption and activation of *NO2. Moreover, the presence of Ovs and PdCu alloy lowers the energy barriers for deoxygenation and hydrogenation, leading to high yield and selectivity of NH3. This insight of controlling localized electron density offers valuable insights for advancing sustainable NH3 synthesis methods.

A novel approach to clinical thinking training for medical students: the combined World Café discussion and case-based learning experience introduction.

It is essential for modern medical students to continuously enhance their clinical thinking abilities. This study aims to evaluate the efficacy of the combined World Café discussion and case-based learning (CBL) approach within the clinical thinking training course. The clinical thinking training course incorporated the combined World Café discussion and CBL approach. The assessment of the accuracy and rationality of clinical symptoms, medical examination, pathological processes, diagnostic results, diagnostic basis, and drug use was conducted through case-related queries. Feedback from students and instructors regarding the teaching content, teaching process, and teaching effect was gathered through questionnaires. The findings indicate that the students achieved high marks in all assessed areas, including clinical symptoms, medical examination, pathological processes, diagnostic results, diagnostic basis, and drug use. The feedback from students and instructors on the teaching content, teaching process, and teaching effect was positive. Medical educators can use our findings to implement the combined World Café discussion and CBL mode to enhance student engagement.NEW & NOTEWORTHY The combined World Café discussion and case-based learning approach was implemented in the clinical thinking training course. Students' scores for clinical symptoms, medical examination, pathological process, diagnostic results, diagnostic basis, and drug use were all excellent. Feedback from both students and teachers on the teaching content, teaching process, and teaching effect was positive.

Emerging ultrasmall luminescent nanoprobes for in vivo bioimaging.

Photoluminescence (PL) imaging has become a fundamental tool in disease diagnosis, therapeutic evaluation, and surgical navigation applications. However, it remains a big challenge to engineer nanoprobes for high-efficiency in vivo imaging and clinical translation. Recent years have witnessed increasing research efforts devoted into engineering sub-10 nm ultrasmall nanoprobes for in vivo PL imaging, which offer the advantages of efficient body clearance, desired clinical translation potential, and high imaging signal-to-noise ratio. In this review, we present a comprehensive summary and contrastive discussion of emerging ultrasmall luminescent nanoprobes towards in vivo PL bioimaging of diseases. We first summarize size-dependent nano-bio interactions and imaging features, illustrating the unique attributes and advantages/disadvantages of ultrasmall nanoprobes differentiating them from molecular and large-sized probes. We also discuss general design methodologies and PL properties of emerging ultrasmall luminescent nanoprobes, which are established based on quantum dots, metal nanoclusters, lanthanide-doped nanoparticles, and silicon nanoparticles. Then, recent advances of ultrasmall luminescent nanoprobes are highlighted by surveying their latest in vivo PL imaging applications. Finally, we discuss existing challenges in this exciting field and propose some strategies to improve in vivo PL bioimaging and further propel their clinical applications.

The Role of mRNA Alternative Splicing in Macrophages Infected with Mycobacterium tuberculosis: A Field Needing to Be Discovered.

Mycobacterium tuberculosis (Mtb) is one of the major causes of human death. In its battle with humans, Mtb has fully adapted to its host and developed ways to evade the immune system. At the same time, the human immune system has developed ways to respond to Mtb. The immune system responds to viral and bacterial infections through a variety of mechanisms, one of which is alternative splicing. In this study, we summarized the overall changes in alternative splicing of the transcriptome after macrophages were infected with Mtb. We found that after infection with Mtb, cells undergo changes, including (1) directly reducing the expression of splicing factors, which affects the regulation of gene expression, (2) altering the original function of proteins through splicing, which can involve gene truncation or changes in protein domains, and (3) expressing unique isoforms that may contribute to the identification and development of tuberculosis biomarkers. Moreover, alternative splicing regulation of immune-related genes, such as IL-4, IL-7, IL-7R, and IL-12R, may be an important factor affecting the activation or dormancy state of Mtb. These will help to fully understand the immune response to Mtb infection, which is crucial for the development of tuberculosis biomarkers and new drug targets.

Regulation of Mycobacterium biofilm development and novel measures against antibiotics resistance.

Currently, there are over 170 recognized species of Mycobacterium, the only genus in the family Mycobacteriaceae. Organisms belonging to this genus are quite diverse with respect to their ability to cause disease in humans. The Mycobacterium genus includes human pathogens (Mycobacterium tuberculosis complex and Mycobacterium leprae) and environmental microorganisms known as non-tuberculosis mycobacteria (NTM). A common pathogenic factor of Mycobacterium is the formation of biofilms. Bacterial biofilms are usually defined as bacterial communities attached to the surface, and are also considered as shared spaces of encapsulated microbial cells, including various extracellular polymeric substrates (EPS), such as polysaccharides, proteins, amyloid proteins, lipids, and extracellular DNA (EDNA), as well as membrane vesicles and humic like microorganisms derived refractory substances. The assembly and dynamics of the matrix are mainly coordinated by second messengers, signaling molecules, or small RNAs. Fully deciphering how bacteria provide structure for the matrix, thereby promoting extracellular reactions and benefiting from them, remains a challenge for future biofilm research. This review introduces a five step development model for biofilms and a new model for biofilm formation, analyses the pathogenicity of biofilms, their interactions with bacteriophages and host immune cells, and the key genes and regulatory networks of mycobacterial biofilms, as well as mycobacterial biofilms and drug resistance, in order to provide a basis for clinical treatment of diseases caused by biofilms.

The Hidden Mechanism: Excited-State Proton-Electron Pair Transfer in Metal Nanocluster Emission.

Comprehending the underlying factors that govern photoluminescence (PL) in metal nanoclusters (NCs) under physiological conditions remains a highly intriguing and unresolved challenge, particularly for their biomedical applications. In this study, we evaluate the critical role of excited-state proton-coupled electron transfer in the emission of metal NCs. Our findings demonstrate that hydronium ion (H3O+) binding can trigger a nonlinear, pH-dependent excited-state concerted electron proton transfer (CEPT) reaction. This involves simultaneous electron transfer from the Au(0) core to the Au(I)-ATT (ATT denotes 6-aza-2-thiothymidine) surface and proton transfer from H3O+ to the ATT ligand in a single step, greatly promoting vibrations and rotations of the Au(I)-ATT surface, resulting in substantial PL quenching of Au10(ATT)6 NCs. Further analyses show that the unique CEPT dynamics are strongly influenced by the opposing effects of increased reorganization energy and a larger pre-exponential factor on the electron transfer rate. Moreover, the proposed excited-state CEPT process is found to be prevalent in core-shell relaxation metal NCs, such as Au25(SR)18 (SR denotes thiolate) NCs, and serves as an important factor in limiting their PL emission. By simply controlling the pKa of the ligands, the emission performance of Au25(SR)18 can be easily regulated in physiological environments.

Novel, high accuracy models for hepatocellular carcinoma prediction based on longitudinal data and cell-free DNA signatures.

BACKGROUND & AIMS: Current hepatocellular carcinoma (HCC) risk scores do not reflect changes in HCC risk resulting from liver disease progression/regression over time. We aimed to develop and validate two novel prediction models using multivariate longitudinal data, with or without cell-free DNA (cfDNA) signatures. METHODS: A total of 13,728 patients from two nationwide multicenter prospective observational cohorts, the majority of whom had chronic hepatitis B, were enrolled. aMAP score, as one of the most promising HCC prediction models, was evaluated for each patient. Low-pass whole-genome sequencing was used to derive multi-modal cfDNA fragmentomics features. A longitudinal discriminant analysis algorithm was used to model longitudinal profiles of patient biomarkers and estimate the risk of HCC development. RESULTS: We developed and externally validated two novel HCC prediction models with a greater accuracy, termed aMAP-2 and aMAP-2 Plus scores. The aMAP-2 score, calculated with longitudinal data on the aMAP score and alpha-fetoprotein values during an up to 8-year follow-up, performed superbly in the training and external validation cohorts (AUC 0.83-0.84). The aMAP-2 score showed further improvement and accurately divided aMAP-defined high-risk patients into two groups with 5-year cumulative HCC incidences of 23.4% and 4.1%, respectively (p = 0.0065). The aMAP-2 Plus score, which incorporates cfDNA signatures (nucleosome, fragment and motif scores), optimized the prediction of HCC development, especially for patients with cirrhosis (AUC 0.85-0.89). Importantly, the stepwise approach (aMAP -> aMAP-2 -> aMAP-2 Plus) stratified patients with cirrhosis into two groups, comprising 90% and 10% of the cohort, with an annual HCC incidence of 0.8% and 12.5%, respectively (p <0.0001). CONCLUSIONS: aMAP-2 and aMAP-2 Plus scores are highly accurate in predicting HCC. The stepwise application of aMAP scores provides an improved enrichment strategy, identifying patients at a high risk of HCC, which could effectively guide individualized HCC surveillance. IMPACT AND IMPLICATIONS: In this multicenter nationwide cohort study, we developed and externally validated two novel hepatocellular carcinoma (HCC) risk prediction models (called aMAP-2 and aMAP-2 Plus scores), using longitudinal discriminant analysis algorithm and longitudinal data (i.e., aMAP and alpha-fetoprotein) with or without the addition of cell-free DNA signatures, based on 13,728 patients from 61 centers across mainland China. Our findings demonstrated that the performance of aMAP-2 and aMAP-2 Plus scores was markedly better than the original aMAP score, and any other existing HCC risk scores across all subsets, especially for patients with cirrhosis. More importantly, the stepwise application of aMAP scores (aMAP -> aMAP-2 -> aMAP-2 Plus) provides an improved enrichment strategy, identifying patients at high risk of HCC, which could effectively guide individualized HCC surveillance.

Mycobacteriophage Derived Lipoarabinomannan Binding Protein for Recognizing Non-Tuberculosis Mycobacteria.

Non-tuberculosis mycobacteria (NTM) is one family of pathogens usually leading to nosocomial infections. Exploration of high-performance biological recognition agent plays a pivotal role for the development of point-of-care testing device and kit for detecting NTM. Mycobacterium smegmatis (M. smegmatis) is a NTM which has been frequently applied as an alternative model for highly pathogenic mycobacteria. Herein, a recombinant tail protein derived from mycobacteriophage SWU1 infecting M. smegmatis was expressed with Escherichia coli system and noted as GP89. It shows a fist-like structure according to the results of homology modeling and ab initio modeling. It is confirmed as a lipoarabinomannan (LAM) binding protein, which can recognize studied NTM genus since abundant LAM constructed with d-mannan and d-arabinan is distributed over the mycobacterial surface. Meanwhile an enhanced green fluorescent protein (eGFP)-fused GP89 protein was acquired with a fusion expression technique. Then GP89 and eGFP-fused GP89 were applied to establish a sensitive and rapid method for fluorescent detection of M. smegmatis with a broad linear range of 1.0 × 102 to 1.0 × 106 CFU mL-1 and a low detection limit of 69 CFU mL-1. Rapid and reliable testing of antimicrobial susceptibility was achieved by the GP89-based fluorescent method. The present work provides a promising recognition agent for studied NTM and opens an avenue for clinical diagnosis of NTM-induced infections.

Diatom Frustules Decorated with Co Nanoparticles for the Advanced Anode of Li-Ion Batteries.

Silica is regarded as a promising anode material for lithium-ion batteries (LIBs) because of its high theoretical capacity. However, large volume variation and poor electrical conductivity are limiting factors for the development of SiO2 anode materials. To solve this problem, combining SiO2 with a conductive phase and designing hollow porous structures are effective ways. In this work, The Co(II)-EDTA chelate on the surface of diatom biosilica (DBS) frustules and obtained DBS@C-Co composites decorated with Co nanoparticles by calcination without a reducing atmosphere is first precipitated. The unique three-dimensional structure of diatom frustules provides enough space for the volume change of silica during lithiation/delithiation. Co nanoparticles effectively improve the electrical conductivity and electrochemical activity of silica. Through the synergistic effect of the hollow porous structure, carbon layer and Co nanoparticles, the DBS@C-Co-60 composite delivers a high reversible capacity of >620 mAh g-1 at 100 mA g-1 after 270 cycles. This study provides a new method for the synthesis of metal/silica composites and an opportunity for the development of natural resources as advanced active materials for LIBs.

Incidence and factors influencing sleep disorders in patients with chronic hepatitis B infection: A case-control study.

Chronic hepatitis B (HBV) infection is a disease that imposes a considerable financial burden on patients and can lead to sleep disorders (SDs), resulting in a serious deterioration to patient quality of life. This study aimed to determine the prevalence of SDs in patients with HBV and the correlated sociodemographic and clinical characteristics. A total of 747 patients with chronic HBV infection were recruited. All patients completed the Pittsburgh Sleep Quality Index (PSQI), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 scale, Social Support Rating Scale, Short Form 36 Health Survey (SF-36), and Visual Analogue Scale (VAS). The total PSQI score of patients with each type of chronic HBV infection was significantly higher compared to healthy Chinese adults (p < .05). The incidence of SDs in HBV carriers and patients with mild HBV, moderate HBV, severe HBV, liver failure, compensated cirrhosis, and decompensated liver cirrhosis was 25%, 26%, 32%, 47%, 56%, 31%, and 49%, respectively. The incidence of SDs in all patients with chronic HBV infection was 30%. Binary logistic regression analysis revealed that the course of disease, aspartate aminotransferase levels, PHQ-9 scores, and VAS scores were independent risk factors for SDs, while the total SF-36 score was a protective factor for SDs (all p < .05). In conclusion, the prevalence of SDs was significantly higher in patients with chronic hepatitis B compared to healthy subjects. The independent risk factors for SDs included disease duration, aspartate aminotransferase levels, depression, and fatigue. Clinicians should pay more attention to SDs in patients with chronic HBV infection.

A flexible electrochemical glucose sensing platform based on an electrospun PVA mat covered with in situ grown silver nanoparticles and a mixed self-assembled monolayer of glucose oxidase and ferrocene.

An electrochemical glucose sensor based on flexible materials is significant for wearable devices used for real-time health monitoring and diagnosis. However, applying flexible electrodes involves complex fabrication processes and might reduce detection sensitivity. To overcome these obstacles, we herein report a novel strategy for preparing a highly flexible enzyme electrode based on an electrospun poly(vinyl alcohol) (PVA) mat decorated with in situ grown silver nanoparticles (nano-Ag) for electrochemical glucose sensing. Ferrocene (Fc) was selected as an electron acceptor for glucose oxidase (GOD) in order to minimize the influence of oxygen. Electron transfer between GOD and Fc was facilitated by confining them within a mixed self-assembled monolayer (SAM) formed on a thin layer of gold deposited on top of the PVA/nano-Ag film. Nano-Ag was found to significantly increase the surface area of the electrode and improve the stability of electrode conductivity during tensile deformation. Electrochemical glucose detection was performed by chronoamperometry in the electroactivity domain of ferrocene, and good linearity (R2 = 0.993) was obtained in the range of 0.2-7 mM with a detection limit of 0.038 mM and a relative standard deviation (RSD) of 1.45% (n = 6). After being stuck to a bendable PDMS slice and bent, respectively, at 30° and 60° 50 times, the electrode showed slight changes in detection results (<4.78%), which remained within 8% when the bending angle increased to 90°. With its high flexibility, good detection performance, and convenient fabrication process, the proposed enzyme electrode showed good potential as a flexible platform for wearable glucose sensing systems.

Selected Bacteria Are Critical for Karst River Carbon Sequestration via Integrating Multi-omics and Hydrochemistry Data.

Recalcitrant dissolved organic carbon (RDOC) produced by microbial carbon pumps (MCPs) in the ocean is crucial for carbon sequestration and regulating climate change in the history of Earth. However, the importance of microbes on RDOC formation in terrestrial aquatic systems, such as rivers and lakes, remains to be determined. By integrating metagenomic (MG) and metatranscriptomic (MT) sequencing, we defined the microbial communities and their transcriptional activities in both water and silt of a typical karst river, the Lijiang River, in Southwest China. Betaproteobacteria predominated in water, serving as the most prevalent population remodeling components of dissolved organic carbon (DOC). Binning method recovered 45 metagenome-assembled genomes (MAGs) from water and silt. Functional annotation of MAGs showed Proteobacteria was less versatile in degrading complex carbon, though cellulose and chitin utilization genes were widespread in this phylum, whereas Bacteroidetes had high potential for the utilization of macro-molecular organic carbon. Metabolic remodeling revealed that increased shared metabolites within the bacterial community are associated with increased concentration of DOC, highlighting the significance of microbial cooperation during producing and remodeling of carbon components. Beta-oxidation, leucine degradation, and mevalonate (MVA) modules were significantly positively correlated with the concentration of RDOC. Blockage of the leucine degradation pathway in Limnohabitans and UBA4660-related MAGs were associated with decreased RDOC in the karst river, while the Fluviicola-related MAG containing a complete leucine degradation pathway was positively correlated with RDOC concentration. Collectively, our study revealed the linkage between bacteria metabolic processes and carbon sequestration. This provided novel insights into the microbial roles in karst-rivers carbon sink.

Preparation of magnetically separable and low-cost MC-FePd3NPs with enhanced catalytic activity in the reduction of p-nitrophenol.

To obtain a magnetically separable, low-cost and highly efficient reduction catalyst, microbial carbon-loaded bimetallic palladium/iron nanoparticles (MC-FePd3NPs) were synthesized in this study by using waste yeast residue doped with iron during the preparation process of microbial carbon-loaded monometallic palladium nanoparticles (MC-Pd NPs). The morphology, crystal structure, magnetic properties and catalytic performance of MC-FePd3NPs for the reduction ofp-nitrophenol (p-NP) were investigated by various characterization techniques, such as SEM-EDS, TEM, XRD, PPMS-9 and UV-vis spectroscopy. The catalytic experiments showed that the MC-FePd3NPs prepared under pyrolysis conditions at 700 °C had an apparent rate constant of 1.85 × 10-1s-1which is better than the rate constants of MC-Pd NPs and other palladium-based nanocatalytic materials reported so far. The amount of palladium used in the synthesis of MC-FePd3NPs was half that of MC-Pd NPs. The catalyst exhibited soft magnetic ordering behavior and still showed a catalytic efficiency of 97.4% after five consecutive reaction cycles. Furthermore, employing MC-FePd3NPs reduces the costs of catalyst preparation and use in production. MC-FePd3NPs with efficient catalytic properties, facile magnetic separation and recyclability, and low costs of preparation and use have considerable potential for industrial applications.

Brain distribution and metabolic profiling of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in rats investigated by UHPLC-HRMS/MS following peripheral administration.

4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is known to be a tobacco-specific N-nitrosamine and has peripheral carcinogenic properties. It can also induce oxidative stress, glial cell activation, and neuronal damage in the brain. However, the distribution and metabolic characteristics of NNK in the central nervous system are still unclear. Here, a sensitive and effective UHPLC-HRMS/MS method was established to identify and investigate the metabolites of NNK and their distribution in the rat brain. In addition, the pharmacokinetic profiles were simultaneously investigated via blood-brain synchronous microdialysis. NNK and its seven metabolites were well quantified in the hippocampus, cortex, striatum, olfactory bulb, brain stem, cerebellum, and other regions of rat brain after peripheral exposure (5 mg/kg, i.p.). The average content of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in all brain regions was at least threefold higher than that of NNK, indicating a rapid carbonyl reduction of NNK in the brain. Lower concentrations of pyridine N-oxidation products in the cortex, olfactory bulb, hippocampus, and striatum might be related to the poor detoxification ability in these regions. Compared to α-methyl hydroxylation, NNK and NNAL were more inclined to the α-methylene hydroxylation pathway. Synchronous pharmacokinetic results indicated that the metabolic activity of NNK in the brain was different from that in the blood. The mean α-hydroxylation ratio in the brain and blood was 0.037 and 0.161, respectively, which indicated poor metabolic activity of NNK in the central nervous system.

Vertical transmission of porcine circovirus-like virus P1 in BALB/c mice.

BACKGROUND: Porcine circovirus-like virus P1 is the animal virus with the smallest genome discovered so far, and it has become widely distributed in the Chinese mainland in recent years. RESULTS: In this study, a BALB/c mouse model was used to reveal P1 infection in female reproductive systems and the vertical transmission of the virus. The female reproductive system, including the ovary and uterus, was harvested on day 14 postinfection and examined for pathological lesions. One-day-old mice without colostrum born from infected or uninfected mothers were collected, and P1 virus distribution in the different organs was investigated. During the trials, all the mice showed no clinical symptoms or gross lesions. However, stillbirth did occur in groups infected with the P1 virus. P1 nucleic acid was detected in the heart, liver, spleen, lung, kidney, and brain tissues of 1-day-old mice born from infected mice. Microscopic lesions in P1-infected female mice were characterized by necrosis of the ovarian follicular granulosa cells and abscission, follicular atresia, necrosis of the endometrial epithelial and uterine glandular epithelial cells, and hyperplasia of the squamous endometrial epithelium. The spermatocytes in the seminiferous tubules of the infected male mice were disorderly arranged, and the germ and Sertoli cells were shed, necrotic, and decreased in number. Immunohistochemical results identified P1-positive particles in the nucleus and cytoplasm of cells from the ovary and uterus of female mice. CONCLUSIONS: This study shows that the P1 virus could cause pathological damage to the reproductive system of female mice and could be transmitted vertically.