584 research outputs found
Controlled manipulation of oxygen vacancies using nanoscale flexoelectricity
Oxygen vacancies, especially their distribution, are directly coupled to the
electromagnetic properties of oxides and related emergent functionalities that
have implication in device applications. Here using a homoepitaxial strontium
titanate thin film, we demonstrate a controlled manipulation of the oxygen
vacancy distribution using the mechanical force from a scanning probe
microscope tip. By combining Kelvin probe force microscopy imaging and
phase-field simulations, we show that oxygen vacancies can move under a
stress-gradient-induced depolarisation field. When tailored, this nanoscale
flexoelectric effect enables a controlled spatial modulation. In motion, the
scanning probe tip thereby deterministically reconfigures the spatial
distribution of vacancies. The ability to locally manipulate oxygen vacancies
on-demand provides a tool for the exploration of mesoscale quantum phenomena,
and engineering multifunctional oxide devices.Comment: 35 pages, Main text and the supplementary information combine
Impact of central venous pressure on the mortality of patients with sepsis-related acute kidney injury: a propensity score-matched analysis based on the MIMIC IV database
Central venous pressure (CVP); Database; MortalityPressió venosa central (PVC); Base de dades; MortalitatPresión venosa central (PVC); Base de datos; MortalidadBackground: Sepsis has long been a life-threatening organ dysfunction. Sepsis associated acute kidney injury (SA-AKI) is an important complication of sepsis, as an important hemodynamic index, the impact of central venous pressure (CVP) on sepsis patients needs to be explored. Thus this study aimed to investigate the relationship between CVP and the mortality of SA-AKI.
Methods: Clinical data of adult patients with sepsis-related acute kidney injury, defined as met both the Sepsis 3.0 criteria and the Kidney Disease Improving Global Outcomes Clinical Practice Guideline (KDIGO) criteria, were obtained from the Medical Information Mart for Intensive Care-IV (MIMIC-IV) database. The included cohort was divided into a high CVP and a low CVP group were determined based on the cuf-off value from receiver operating characteristic curve, with propensity score-matched analysis of the 28-day mortality for both groups and sensitivity analysis using inverse the probability-weighting model, multifactorial regression, and doubly robust estimation, patients acquired chronic coronary syndrome (CCS) and diabetes were also taken into consideration.
Results: Of 1,377 patients with sepsis-related acute kidney injury, low CVP group (<13 mmHg) was 67.4% (n=928) and high CVP group (≥13 mmHg) was 32.6% (n=449). The two groups were matched 1:1 by propensity score to obtain a matched cohort (n=288). The mortality rates in the low versus high CVP group (19.4% vs. 34.7%) were statistically difference (odds ratio OR: 0.454; 95% confidence interval 0.263, 0.771). Moreover, the bistable analysis of logistic regression of the matched cohort (OR: 0.434; 95% CI: 0.244, 0.757), propensity score inverse probability weighting (IPW) (OR: 0.547; 95% CI: 0.454, 0.658), and multifactorial logistic regression (OR: 0.352; 95% CI: 0.127, 0.932) all yielded the same results.
Conclusions: In patients with sepsis-related acute kidney injury, a lower CVP level (<13 mmHg) is an independent variable associated with decreased mortality. The threshold of CVP needs to be controlled in clinical work to improve the prognosis of patients with SA-AKI
Design and Mechanical Compatibility of Nylon Bionic Cancellous Bone Fabricated by Selective Laser Sintering
In order to avoid the stress shielding phenomenon in orthopedic bionic bone implantation, it is necessary to consider the design of mechanical compatible implants imitating the host bone. In this study, we developed a novel cancellous bone structure design method aimed at ensuring the mechanical compatibility between the bionic bone and human bone by means of computer-aided design (CAD) and finite element analysis technology (specifically, finite element modeling (FEM)). An orthogonal lattice model with volume porosity between 59% and 96% was developed by means of CAD. The effective equivalent elastic modulus of a honeycomb structure with square holes was studied by FEM simulation. With the purpose of verifying the validity of the cancellous bone structure design method, the honeycomb structure was fabricated by selective laser sintering (SLS) and the actual equivalent elastic modulus of the honeycomb structure was measured with a uniaxial compression test. The experimental results were compared with the FEM values and the predicted values. The results showed that the stiffness values of the designed structures were within the acceptable range of human cancellous bone of 50-500 MPa, which was similar to the stiffness values of human vertebrae L1 and L5. From the point of view of mechanical strength, the established cellular model can effectively match the elastic modulus of human vertebrae cancellous bone. The functional relationship between the volume porosity of the nylon square-pore honeycomb structure ranging from 59% to 96% and the effective elastic modulus was established. The effect of structural changes related to the manufacture of honeycomb structures on the equivalent elastic modulus of honeycomb structures was studied quantitatively by finite element modeling
Mouse Model Resources for Vision Research
The need for mouse models, with their well-developed genetics and similarity to human physiology and anatomy, is clear and their central role in furthering our understanding of human disease is readily apparent in the literature. Mice carrying mutations that alter developmental pathways or cellular function provide model systems for analyzing defects in comparable human disorders and for testing therapeutic strategies. Mutant mice also provide reproducible, experimental systems for elucidating pathways of normal development and function. Two programs, the Eye Mutant Resource and the Translational Vision Research Models, focused on providing such models to the vision research community are described herein. Over 100 mutant lines from the Eye Mutant Resource and 60 mutant lines from the Translational Vision Research Models have been developed. The ocular diseases of the mutant lines include a wide range of phenotypes, including cataracts, retinal dysplasia and degeneration, and abnormal blood vessel formation. The mutations in disease genes have been mapped and in some cases identified by direct sequencing. Here, we report 3 novel alleles of Crxtvrm65, Rp1tvrm64, and Rpe65tvrm148 as successful examples of the TVRM program, that closely resemble previously reported knockout models
Psychometric Properties of the Hypomania Checklist-32 in Korean Patients with Mood Disorders
OBJECTIVE
The aim of this study was to examine the validity of the Korean version of the Hypomania Checklist-32, second revision (HCL-32-R2) in mood disorder patients.
METHODS
A total of 454 patients who diagnosed as mood disorder according to Structured Clinical Interview for DSM-IV Axis I Disorders, clinician version (SCID-CV) (bipolar disorder [BD] I, n=190; BD-II, n=72; and major depressive disorder [MDD], n=192) completed the Korean module of the HCL-32-R2 (KHCL-32-R2).
RESULTS
The KHCL-32-R2 showed a three-factorial structure (eigenvalue >2) that accounted for 43.26% of the total variance. Factor 1 was labeled "active/elated" and included 16 items; factor 2, "irritable/distractible" and included 9 items; and factor 3 was labeled "risk-taking/indulging" and included 9 items. A score of 16 or more on the KHCL-32-R2 total scale score distinguished between BD and MDD, which yielded a sensitivity of 70% and a specificity of 70%. MDD and BD-II also could be differentiated at a cut-off of 15 with maximized sensitivity (0.67) and specificity (0.66). Cronbach's alpha of KHCL-32-R2 and its subsets (factors 1, 2, and 3) were 0.91, 0.89, 0.81 and 0.79, respectively. Correlations between KHCL-32-R2 and Montgomery- Asberg Depression Rating Scale, Young Mania Rating Scale and Korean version of Mood Disorder Questionnaire were -0.66 (p=0.41), -0.14 (p=0.9), and 0.61 (p<0.001), respectively.
CONCLUSION
The KHCL-32-R2 may be a useful tool in distinguishing between bipolar and depressive patients in clinical settings
Characterization of Pv92, a novel merozoite surface protein of Plasmodium vivax
The discovery and understanding of antigenic proteins are essential for development of a vaccine against malaria. In Plasmodium falciparum, Pf92 have been characterized as a merozoite surface protein, and this protein is expressed at the late schizont stage, but no study of Pv92, the orthologue of Pf92 in P. vivax, has been reported. Thus, the protein structure of Pv92 was analyzed, and the gene sequence was aligned with that of other Plasmodium spp. using bioinformatics tools. The recombinant Pv92 protein was expressed and purified using bacterial expression system and used for immunization of mice to gain the polyclonal antibody and for evaluation of antigenicity by protein array. Also, the antibody against Pv92 was used for subcellular analysis by immunofluorescence assay. The Pv92 protein has a signal peptide and a sexual stage s48/45 domain, and the cysteine residues at the N-terminal of Pv92 were completely conserved. The N-terminal of Pv92 was successfully expressed as soluble form using a bacterial expression system. The antibody raised against Pv92 recognized the parasites and completely merged with PvMSP1-19, indicating that Pv92 was localized on the merozoite surface. Evaluation of the human humoral immune response to Pv92 indicated moderate antigenicity, with 65% sensitivity and 95% specificity by protein array. Taken together, the merozoite surface localization and antigenicity of Pv92 implicate that it might be involved in attachment and invasion of a merozoite to a new host cell or immune evasion during invasion process.Publisher PDFPeer reviewe
Identification of a reticulocyte-specific binding domain of Plasmodium vivax reticulocyte-binding protein 1 that is homologous to the PfRh4 erythrocyte-binding domain
The Plasmodium vivax reticulocyte-binding protein (RBP) family was identified based on the annotation of adhesive ligands in the P. vivax genome. Reticulocyte-specific interactions with the PvRBPs (PvRBP1 and PvRBP2) were previously reported. Plasmodium falciparum reticulocyte-binding protein homologue 4 (PfRh4, a homologue of PvRBP1) was observed to possess erythrocyte-binding activity via complement receptor 1 on the erythrocyte surface. However, the reticulocyte-binding mechanisms of P. vivax are unclear because of the large molecular mass of PvRBP1 (>326 kDa) and the difficulty associated with in vitro cultivation. In the present study, 34 kDa of PvRBP1a (PlasmoDB ID: PVX_098585) and 32 kDa of PvRBP1b (PVX_098582) were selected from a 30 kDa fragment of PfRh4 for reticulocyte-specific binding activity analysis. Both PvRBP1a and PvRBP1b were found to be localized at the microneme in the mature schizont-stage parasites. Naturally acquired immune responses against PvRBP1a-34 and PvRBP1b-32 were observed lower than PvDBP-RII. The reticulocyte-specific binding activities of PvRBP1a-34 and PvRBP1b-32 were significantly higher than normocyte binding activity and were significantly reduced by chymotrypsin treatment. PvRBP1a and 1b, bind to reticulocytes and that this suggests that these ligands may have an important role in P. vivax merozoite invasion.Publisher PDFPeer reviewe
Aldose Reductase Inhibitor Ameliorates Renal Vascular Endothelial Growth Factor Expression in Streptozotocin-Induced Diabetic Rats
PURPOSE: The vascular endothelial growth factor (VEGF) expression of podocyte is one of the well-known major factors in development of diabetic nephropathy. In this study, we investigated the effects of aldose reductase inhibitor, fidarestat on diabetic nephropathy, and renal VEGF expression in a type 1 diabetic rat model.
MATERIALS AND METHODS: Twenty four Sprague-Dawley male rats which were performed intraperitoneal injection of streptozotocin and normal six rats were divided into four groups including a normal control group, untreated diabetic control group, aldose reductase (AR) inhibitor (fidarestat, 16 mg kg(-1) day(-1)) treated diabetic group, and angiotensin receptor blocker (losartan, 20 mg kg(-1) day(-1)) treated diabetic group. We checked body weights and blood glucose levels monthly and measured urine albumin-creatinine ratio (ACR) at 8 and 32 weeks. We extracted the kidney to examine the renal morphology and VEGF expressions.
RESULTS: The ACR decreased in fidarestat and losartan treated diabetic rat groups than in untreated diabetic group (24.79 +/- 11.12, 16.11 +/- 9.95, and 84.85 +/- 91.19, p < 0.05). The renal VEGF messenger RNA (mRNA) and protein expression were significantly decreased in the fidarestat and losartan treated diabetic rat groups than in the diabetic control group.
CONCLUSION: We suggested that aldose reductase inhibitor may have preventive effect on diabetic nephropathy by reducing renal VEGF overexpression.ope
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