84 research outputs found

    Epidemiology and clinical features of Skin and Soft Tissue Infections Caused by PVL-Positive and PVL-Negative Methicillin-Resistant <i>Staphylococcus aureus</i> Isolates in inpatients in China: a single-center retrospective 7-year study.

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    Previous studies have mainly focused on outpatient cases of skin and soft tissue infections (SSTIs), with limited attention to inpatient occurrences. Thus, we aimed to compare the clinical parameters of inpatients with SSTIs, performed genomic characterization, and determined the subtypes of Panton-Valentine leucocidin (PVL) bacteriophages of methicillin-resistant Staphylococcus aureus (MRSA) strains isolated from these patients. We found that PVL-positive patients had shorter hospital stays (mean, 9 vs. 24 days; p lukSF-PV gene, revealing that major clusters were associated with specific STs, suggesting independent acquisition of PVL by different strain types and indicating that significant diversity was observed even within PVL-positive strains detected in the same facility. Overall, our study provides comprehensive insights into the clinical, genetic, and phage-related aspects of MRSA-induced SSTIs in hospitalized patients and contributes to a more profound understanding of the epidemiology and evolution of these pathogens in the Chinese population.</p

    Generalized Optimized Effective Potential for Orbital Functionals and Self-Consistent Calculation of Random Phase Approximations

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    A new self-consistent procedure for calculating the total energy with an orbital-dependent density functional approximation (DFA), the generalized optimized effective potential (GOEP), is developed in the present work. The GOEP is a nonlocal Hermitian potential that delivers the sets of occupied and virtual orbitals and minimizes the total energy. The GOEP optimization leads to the same minimum as does the orbital optimization. The GOEP method is promising as an effective optimization approach for orbital-dependent functionals, as demonstrated for the self-consistent calculations of the random phase approximation (RPA) to the correlation functionals in the particle–hole (ph) and particle–particle (pp) channels. The results show that the accuracy in describing the weakly interacting van der Waals systems is significantly improved in the self-consistent calculations. In particular, the important single excitations contribution in non-self-consistent RPA calculations can be captured self-consistently through the GOEP optimization, leading to orbital renormalization, without using the single excitations in the energy functional

    Multireference Density Functional Theory with Generalized Auxiliary Systems for Ground and Excited States

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    To describe static correlation, we develop a new approach to density functional theory (DFT), which uses a generalized auxiliary system that is of a different symmetry, such as particle number or spin, from that of the physical system. The total energy of the physical system consists of two parts: the energy of the auxiliary system, which is determined with a chosen density functional approximation (DFA), and the excitation energy from an approximate linear response theory that restores the symmetry to that of the physical system, thus rigorously leading to a multideterminant description of the physical system. The electron density of the physical system is different from that of the auxiliary system and is uniquely determined from the functional derivative of the total energy with respect to the external potential. Our energy functional is thus an implicit functional of the physical system density, but an explicit functional of the auxiliary system density. We show that the total energy minimum and stationary states, describing the ground and excited states of the physical system, can be obtained by a self-consistent optimization with respect to the explicit variable, the generalized Kohn–Sham noninteracting density matrix. We have developed the generalized optimized effective potential method for the self-consistent optimization. Among options of the auxiliary system and the associated linear response theory, reformulated versions of the particle–particle random phase approximation (pp-RPA) and the spin-flip time-dependent density functional theory (SF-TDDFT) are selected for illustration of principle. Numerical results show that our multireference DFT successfully describes static correlation in bond dissociation and double bond rotation

    Comparison of Critical Adsorption Points of Ring Polymers with Linear Polymers

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    The critical adsorption points (CAP) for ring and linear polymers are determined and compared using Monte Carlo simulations and liquid chromatography experiments. The CAP is defined as the coelution point of ring or linear polymers with different molecular weights (MW). Computational studies show that the temperature at the CAP, <i>T</i><sub>CAP</sub>, for rings is higher than <i>T</i><sub>CAP</sub> for linear polymers regardless of whether the chains are modeled as random walks or self-avoiding walks. The difference in the CAP can be attributed only to the architectural difference. Experimentally, four pairs of linear and ring polystyrenes (PS) of different MW were synthesized and purified. Care was taken to account for the difference between the end-groups in linear polymers and the linkage unit in ring polymers. Elution of these polymers using a C18 bonded silica stationary phase and a CH<sub>2</sub>Cl<sub>2</sub>/CH<sub>3</sub>CN mixed eluent were studied. The temperature at the coelution point, <i>T</i><sub>CAP</sub>, and the coelution time at the CAP, <i>t</i><sub>E,CAP</sub>, were determined for both ring and linear polymers. Experimentally, it was found that <i>T</i><sub>CAP</sub> of linear PS is lower than <i>T</i><sub>CAP</sub> of cyclic PS and <i>t</i><sub>E,CAP</sub> of linear PS is shorter than <i>t</i><sub>E,CAP</sub> of ring PS. Therefore, at the CAP of linear polymers, ring polymers elute later in order of increasing MW while, at the CAP of ring polymers, linear polymers elute earlier in order of decreasing MW. This is in excellent agreement with the Monte Carlo computer simulation results. We also found that the functionality effect can interfere in the LCCC separation of ring polymers from their linear precursors

    Quantum Dots Encapsulated with Canine Parvovirus-Like Particles Improving the Cellular Targeted Labeling

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    <div><p>Quantum dots (QDs) have a promising prospect in live-cell imaging and sensing because of unique fluorescence features. QDs aroused significant interest in the bio-imaging field through integrating the fluorescence properties of QDs and the delivery function of biomaterial. The natural tropism of Canine Parvovirus (CPV) to the transferrin receptor can target specific cells to increase the targeting ability of QDs in cell imaging. CPV virus-like particles (VLPs) from the expression of the CPV-VP2 capsid protein in a prokaryotic expression system were examined to encapsulate the QDs and deliver to cells with an expressed transferrin receptor. CPV-VLPs were used to encapsulate QDs that were modified using 3-mercaptopropionic acid. Gel electrophoresis, fluorescence spectrum, particle size, and transmission electron microscopy verified the conformation of a complex, in which QDs were encapsulated in CPV-VLPs (CPV-VLPs-QDs). When incubated with different cell lines, CPV-VLPs-QDs significantly reduced the cytotoxicity of QDs and selectively labeled the cells with high-level transferrin receptors. Cell-targeted labeling was achieved by utilizing the specific binding between the CPV capsid protein VP2 of VLPs and cellular receptors. CPV-VLPs-QDs, which can mimic the native CPV infection, can recognize and attach to the transferrin receptors on cellular membrane. Therefore, CPV-VLPs can be used as carriers to facilitate the targeted delivery of encapsulated nanomaterials into cells via receptor-mediated pathways. This study confirmed that CPV-VLPs can significantly promote the biocompatibility of nanomaterials and could expand the application of CPV-VLPs in biological medicine.</p></div

    Table_4_Splenectomy Leads to Amelioration of Altered Gut Microbiota and Metabolome in Liver Cirrhosis Patients.xlsx

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    <p>Dysbiosis of gut microbiota and metabolome is a frequently encountered condition in liver cirrhosis (LC) patients. The severity of liver dysfunction was found to be correlated with the degree of microbial dysbiosis. Several clinical studies have indicated liver function improvement after therapeutic splenectomy for LC-induced hypersplenism. We sought to determine whether such post-splenectomy outcome is pertinent to modulation of the abnormal gut microenvironment in LC patients. A cross-sectional study including 12 LC patients and 16 healthy volunteers was first conducted, then a before–after study in the cohort of patients was carried out before and 6 months after splenectomy. Fecal samples were collected in hospital. Temporal bacterial (n = 40) and metabolomics (n = 30) profiling was performed using 16s rRNA gene sequencing and ultra performance liquid chromatography/mass spectrometer (UPLC/MS), respectively. Our results revealed that microbial composition in patients was clearly different from that in healthy controls (HCs), evidenced by considerable taxonomic variation. Along with improved liver function (Child–Pugh score), the patients also displayed similar gut microbiota profile and predicted metagenome function to that of HCs after splenectomy. Enterobacteriaceae and Streptococcaceae, two LC-enriched families showing positive relation with Child–Pugh score, exhibited significantly decreased abundance after splenectomy. At the genus level, 11 genera were differentially abundant between patients and HCs, but 9 genera of them restituted to normal levels by certain degree after splenectomy. PICRUSt analysis showed that the relative abundance of 17 KEGG pathways was partially restored after splenectomy. Four of them were amino acid-related pathways: lysine degradation, tryptophan degradation, amino acid metabolism, and protein digestion and absorption. These findings were supported by metabonomics results which showed that relative abundance of amino acid and corresponding catabolites changed toward normal. In addition to the variations in the relative abundances of bacteria and metabolites, the correlation between them also altered in patients after splenectomy. Dysbiosis in gut microbiome and related metabolism of LC patients was partially corrected after splenectomy. Whether the improved gut microenvironment could prevent LC-related complications and delay the progress of LC is a propitious objective for future study. Trial registration: ChiCTR-OOB-15007409. Registered November 15, 2015.</p

    Table_2_Splenectomy Leads to Amelioration of Altered Gut Microbiota and Metabolome in Liver Cirrhosis Patients.XLSX

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    <p>Dysbiosis of gut microbiota and metabolome is a frequently encountered condition in liver cirrhosis (LC) patients. The severity of liver dysfunction was found to be correlated with the degree of microbial dysbiosis. Several clinical studies have indicated liver function improvement after therapeutic splenectomy for LC-induced hypersplenism. We sought to determine whether such post-splenectomy outcome is pertinent to modulation of the abnormal gut microenvironment in LC patients. A cross-sectional study including 12 LC patients and 16 healthy volunteers was first conducted, then a before–after study in the cohort of patients was carried out before and 6 months after splenectomy. Fecal samples were collected in hospital. Temporal bacterial (n = 40) and metabolomics (n = 30) profiling was performed using 16s rRNA gene sequencing and ultra performance liquid chromatography/mass spectrometer (UPLC/MS), respectively. Our results revealed that microbial composition in patients was clearly different from that in healthy controls (HCs), evidenced by considerable taxonomic variation. Along with improved liver function (Child–Pugh score), the patients also displayed similar gut microbiota profile and predicted metagenome function to that of HCs after splenectomy. Enterobacteriaceae and Streptococcaceae, two LC-enriched families showing positive relation with Child–Pugh score, exhibited significantly decreased abundance after splenectomy. At the genus level, 11 genera were differentially abundant between patients and HCs, but 9 genera of them restituted to normal levels by certain degree after splenectomy. PICRUSt analysis showed that the relative abundance of 17 KEGG pathways was partially restored after splenectomy. Four of them were amino acid-related pathways: lysine degradation, tryptophan degradation, amino acid metabolism, and protein digestion and absorption. These findings were supported by metabonomics results which showed that relative abundance of amino acid and corresponding catabolites changed toward normal. In addition to the variations in the relative abundances of bacteria and metabolites, the correlation between them also altered in patients after splenectomy. Dysbiosis in gut microbiome and related metabolism of LC patients was partially corrected after splenectomy. Whether the improved gut microenvironment could prevent LC-related complications and delay the progress of LC is a propitious objective for future study. Trial registration: ChiCTR-OOB-15007409. Registered November 15, 2015.</p

    Optimization of QDs encapsulation using CPV-VLPs.

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    <p>(<b>a</b>) Particle size of CPV-VLPs-QDs under different CPV-VLPs/QDs ratios. (<b>b</b>)Absorbance of complex at different CPV-VLPs/QDs ratios.</p
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