Promoting Water Oxidation by Proton Acceptable Groups Surrounding Catalyst on Electrode Surface.

Large-scale hydrogen production through water splitting represents an optimal approach for storing sustainable but intermittent energy sources. However, water oxidation, a complex and sluggish reaction, poses a significant bottleneck for water splitting efficiency. The impact of outer chemical environments on the reaction kinetics of water oxidation catalytic centers remains unexplored. Herein, chemical environment impacts were integrated by featuring methylpyridinium cation group (Py+) around the classic Ru(bpy)(tpy) (bpy=2,2'-bipyridine, tpy=2,2' : 6',2''-terpyridine) water oxidation catalyst on the electrode surface via electrochemical co-polymerization. The presence of Py+ groups could significantly enhance the turnover frequencies of Ru(bpy)(tpy), surpassing the performance of typical proton acceptors such as pyridine and benzoic acid anchored around the catalyst. Mechanistic investigations reveal that the flexible internal proton acceptor anions induced by Py+ around Ru(bpy)(tpy) are more effective than conventionally anchored proton acceptors, which promoted the rate-determining proton transfer process and enhanced the rate of water nucleophilic attack during O-O bond formation. This study may provide a novel perspective on achieving efficient water oxidation systems by integrating cations into the outer chemical environments of catalytic centers.

Topology-sensitive weighting model for myocardial segmentation.

Accurate myocardial segmentation is crucial for the diagnosis of various heart diseases. However, segmentation results often suffer from topology structural errors, such as broken connections and holes, especially in cases of poor image quality. These errors are unacceptable in clinical diagnosis. We proposed a Topology-Sensitive Weight (TSW) model to keep both pixel-wise accuracy and topological correctness. Specifically, the Position Weighting Update (PWU) strategy with the Boundary-Sensitive Topology (BST) module can guide the model to focus on positions where topological features are sensitive to pixel values. The Myocardial Integrity Topology (MIT) module can serve as a guide for maintaining myocardial integrity. We evaluate the TSW model on the CAMUS dataset and a private echocardiography myocardial segmentation dataset. The qualitative and quantitative experimental results show that the TSW model significantly enhances topological accuracy while maintaining pixel-wise precision.

A signal-amplification electrochemiluminescence sensor based on layer-by-layer assembly of perylene diimide derivatives for dopamine detection at low potential.

Perylene diimide derivatives (PDIs) are suitable ECL luminophore candidates with low triggering potentials and strong ECL signals for fundamental studies and practical applications. However, PDIs tend to aggregate, which affects their optical properties and limits their application in bio-imaging and bio-sensing fields. In this study, an ECL sensor is fabricated based on the layer-by-layer (LBL) assembly of N, N-bis(phosphonomethyl)-3,4,9,10-perylene diimide (PMPDI) and ZrIV ions on the surface of a mesoporous indium tin oxide (ITO) substrate. When six layers of PMPDI are immobilized on ITO, the resulting PMPDI6/ITO electrode shows maximum ECL intensity with K2S2O8 as a co-reactant in the potential range 0 to -0.5 V vs. Ag/AgCl. LBL assembly decreases the aggregation and increases the loading of PMPDI on the mesoporous ITO substrate, which stabilizes and amplifies the ECL signals. The ECL method exhibits excellent sensitivity and selectivity with good stability and reproducibility, when used to detect dopamine (DA) under optimal experimental conditions.

Neuropeptide S and its receptor NPSR enhance the susceptibility of hosts to pseudorabies virus infection.

The neuropeptide S (NPS) and its receptor (NPSR) represent a signaling system in the brain. Increased levels of NPS and NPSR have been observed in PK15 cells and murine brains in response to pseudorabies virus (PRV) infection, but it remains unclear whether elevated levels of NPS and NPSR are involved in the pathogenic process of PRV infection. In this study, the activities of both NPS and NPSR during PRV pathogenesis were explored in vitro and in vivo by reverse transcription polymerase chain reaction (RT-PCR), PCR, real-time quantitative RT-PCR (qRT-PCR), qPCR, TCID50, and Western blotting methods. NPSR-deficient cells were less susceptible to PRV infection, as evidenced by decreased viral production and PRV-glycoprotein E (gE) expression. In vitro studies showed that exogenous NPS promoted the expression of interleukin 6 (IL-6) mRNA but inhibited interferon ß (IFN-ß) mRNA expression in PK15 cells after PRV infection. In vivo studies showed that NPS-treated mice were highly susceptible to PRV infection, with decreased survival rates and body weights. In addition, NPS-treated mice showed elevated levels of IL-6 mRNA and STAT3 phosphorylation. However, the expression of IFN-ß mRNA was greatly decreased after virus challenge. Contrasting results were obtained from the NPSR-ir-treated groups, which further highlighted the effects of NPS. This study revealed that NPS-treated hosts are more susceptible to PRV infection than controls. Moreover, excessive IL-6/STAT3 and defective IFN-ß responses in NPS-treated mice may contribute to the pathogenesis of PRV.

The Evaluation of Longitudinal Strain of Large and Small Abdominal Aortic Aneurysm by Two-Dimensional Speckle-Tracking Ultrasound.

OBJECTIVES: Abdominal aortic aneurysm (AAA) is a dangerous and lethal vascular disease. Non-invasive two-dimensional speckle-tracking imaging (2D STI) plays an important role in assessing aortic biomechanical properties. Our study aimed to evaluate the alterations of biomechanical characteristics using 2D STI in 91 AAA patients with different size. METHODS: Aneurysm strain, elastic modulus, stiffness index ß, and aortic distensibility determined by M-Mode ultrasound (US), and longitudinal strain (LS) derived from 2D STI were compared in 40 large AAA patients (diameter ≥ 55 mm) and 51 small AAA patients (diameter < 55 mm). RESULTS: Compared with small AAA group, anterior wall longitudinal strain (ALS) and posterior wall longitudinal strain (PLS) were significantly decreased in large AAA group (all P < .05) and not affected by age, symptom, hypertension, and thrombus. Meanwhile, ALS and PLS correlated negatively with maximal aneurysm diameters (r = -0.628 and -0.469, respectively, all P < .001). And only ALS was associated with M-Mode US parameters (all P < .05). Based on receiver operating characteristic (ROC) analysis, ALS and PLS had strong diagnostic values for large AAA with the area under the curve (AUC) of 0.82 and 0.72, and cut-off points of 1.71 and 1.64% with a sensitivity of 78 and 72%, and a specificity of 75 and 70%, respectively. CONCLUSIONS: LS measured by 2D STI could evaluate the biomechanical properties of aneurysm wall with different size, and add additional diagnostic value in distinguishing between small and large AAA.

Determination of aortic pulse transit time based on waveform decomposition of radial pressure wave.

Carotid-femoral pulse transit time (cfPTT) is a widely accepted measure of central arterial stiffness. The cfPTT is commonly calculated from two synchronized pressure waves. However, measurement of synchronized pressure waves is technically challenging. In this paper, a method of decomposing the radial pressure wave is proposed for estimating cfPTT. From the radial pressure wave alone, the pressure wave can be decomposed into forward and backward waves by fitting a double triangular flow wave. The first zero point of the second derivative of the radial pressure wave and the peak of the dicrotic segment of radial pressure wave are used as the peaks of the fitted double triangular flow wave. The correlation coefficient between the measured wave and the estimated forward and backward waves based on the decomposition of the radial pressure wave was 0.98 and 0.75, respectively. Then from the backward wave, cfPTT can be estimated. Because it has been verified that the time lag estimation based on of backward wave has strong correlation with the measured cfPTT. The corresponding regression function between the time lag estimation of backward wave and measured cfPTT is y = 0.96x + 5.50 (r = 0.77; p < 0.001). The estimated cfPTT using radial pressure wave decomposition based on the proposed double triangular flow wave is more accurate and convenient than the decomposition of the aortic pressure wave based on the triangular flow wave. The significance of this study is that arterial stiffness can be directly estimated from a noninvasively measured radial pressure wave.

Assessment of the Global and Regional Circumferential Strain of Abdominal Aortic Aneurysm with Different Size by Speckle-Tracking Echocardiography.

OBJECTIVES: We aimed to use speckle-tracking echocardiography (STE) to quantify circumferential aortic strain of abdominal aortic aneurysms (AAA) with different size. METHODS: A total of 87 AAA patients were included. The morphological variables, including aortic maximum diameter (MD), end systolic area (ESA), end diastolic area (EDA), and thickness and area of intraluminal thrombus (ILT), were measured by ultrasound. STE was applied to calculate circumferential strain (CS) at 6 equally divided segments of the aorta at MD. We evaluated the mean value of peak strain along the 6 segments as global circumferential strain (GCS). RESULTS: Large AAA (≥5.5 cm) patients had higher MD, ESA, EDA, AAA length, ILT thickness, and area, but lower fractional area change, GCS, and segmental CSs than small AAA (<5.5 cm) subjects (all P < .05). Compared with AAA <4.5 cm group, AAA patients ≥4.5 cm possessed increased MD, ESA, EDA, AAA length, ILT thickness, and area, which results were also reflected in the comparison between AAA <6.5 and ≥6.5 cm group. In small AAA patients, GCS and regional strains in CS1, CS3, and CS5 segments were lower in AAA subjects ≥4.5 cm than those <4.5 cm (all P<.05). However, no significant differences in the GCS and regional CS between ≥6.5 and <6.5 cm group were found. Correlation analysis revealed a significant negative association of GCS with MD, ESA, and EDA, even after adjusting the potential confounding factors (all P < .05). CONCLUSIONS: Our findings may yield insight into the structural strain characteristics of AAA wall with different size, which adds the benefit of using simple echocardiography-derived biomechanics to stratify AAA patients.

Association of Toll-Like Receptor 4 Gene Polymorphisms with Acute Aortic Dissection in a Chinese Han Population.

BACKGROUND: Inflammation may be involved in the pathogenesis of acute aortic dissection (AAD). Toll-like receptor 4 (TLR4) is known to play a critical role in regulating the immune and inflammatory processes. To date, the relationship between genetic variation of TLR4 and AAD is far from clear. The purpose of our study was to illustrate the relevance of TLR4 polymorphisms with the susceptibility to AAD. METHODS: A total of 222 AAD patients and 222 controls were enrolled in this study. Frequency distributions of TLR4 polymorphisms (rs10759932 in the promoter and rs11536889 in the 3'-untranslated region) were determined by the KASP method. Clinical parameters were acquired from subjects' medical records, and serum TLR4 levels were collected from our previously published data. RESULTS: We found that rs10759932 polymorphism was associated with a reduced risk of AAD in the overall population (CC vs. TT: OR = 0.393, 95%CI = 0.164-0.939, P = 0.036; recessive model: OR = 0.439, 95%CI = 0.196-0.984, P = 0.045) and subgroup analyses stratified by sex. The GC genotype and dominant model of rs11536889 conferred a significantly higher risk of AAD compared with GG genotype in female subjects (GC vs. GG: OR = 3.382, 95%CI = 1.051-10.885, P = 0.041; dominant model: OR = 3.043, 95%CI = 1.041-8.900, P = 0.042). In addition, a significant interaction between the rs11536889 recessive model and dyslipidemia was observed for an increased risk of AAD (P interaction = 0.038, OR = 15.229) after the adjustment for potential clinical covariates. We also used the false-positive report probability (FPRP) analysis to validate the significant results. Furthermore, rs11536889 polymorphism could affect the maximal aortic diameters of AAD (P = 0.037), while AAD patients carrying CC genotype of rs10759932 showed lower serum TLR4 levels than TT genotype carriers (P = 0.043). CONCLUSIONS: Our findings provide evidence for the association between TLR4 polymorphisms and AAD susceptibility in a Chinese Han population, which may have some implications for understanding the role of TLR4 in the pathophysiology of AAD.

Right atrial function for the prediction of prognosis in connective tissue disease-associated pulmonary arterial hypertension: a study with two-dimensional speckle tracking.

Pulmonary arterial hypertension (PAH) is a serious and often fatal complication of connective tissue disease (CTD). Right atrial (RA) function is essential to maintaining adequate total right heart function in PAH. However, little is known about prognostic utility of RA function in CTD-PAH. RA longitudinal strain (LS) and strain rate (LSR) were evaluated in 53 consecutive patients (51 female, mean age 42 ± 15 years) with CTD-PAH, including systemic lupus erythematosus (SLE) (33.7%), mixed connective tissue disease (MCTD) (32.1%), primary Sjögren's syndrome (pSS) (26.4%), and systemic sclerosis (SSc) (3.8%). At a mean follow-up of 19.3 ± 10.9 months, 20 patients (37.7%) were clinically worse. The group with clinical events had worse clinical conditions and poorer RA function at baseline compared with the group that had no clinical events. RA LS independently reflected World Health Organization functional class (WHO FC) after adjusting for RA area (RAA), tricuspid regurgitation (TR) grade, right ventricular (RV) global longitudinal strain (GLS), and pulmonary vascular resistance (PVR) (P = 0.006). Receiver operator characteristic (ROC) curve analysis indicated that RA LS < 22.9% was predictive of clinical worsening during follow-up (sensitivity = 80%; specificity = 87.9%; area under the curve (AUC) = 0.858), and the Kaplan-Meier curve confirmed that RA LS ≥ 22.9% was associated with more favorable long-term outcomes compared to RA LS < 22.9% (log-rank P < 0.01). On univariate Cox proportional hazards analysis, PVR, RVGLS, RAA, and RA LS were associated with long-term outcome, while RA LS was the only independent predictor in the multivariate analysis. Our findings suggest that RA LS measurements by speckle-tracking echocardiography (STE) can independently reflect the extent of right heart failure and predict clinical outcomes in patients with CTD-PAH. RA LS < 22.9% is associated with a higher risk of clinical worsening.

Comparative performance of electrochemiluminescence immunoassay and EIA for HIV screening in a multiethnic region of China.

BACKGROUND: The recent approval of 4th generation HIV tests has forced many laboratories to decide whether to shift from 3rd to these tests. There are limited published studies on the comparative evaluation of these two different assays. We compare the performance of fourth-generation electrochemiluminescence immunoassay (ChIA) and third-generation enzyme linked immunosorbent assay (EIA) for human immunodeficiency virus (HIV) screening and gauge whether the shift from EIA to ChIA could be better in a multiethnic region of China. METHODOLOGY/PRINCIPAL FINDINGS: We identified a large number of routine specimens (345,492) using two different assays from Jan 2008 to Aug 2011 in a teaching hospital with high sample throughput. Of the 344,596 specimens with interpretable HIV test results, 526(0.23%) of 228,761 using EIA and 303(0.26%) of 115,835 using ChIA were HIV-1 positive. The false-positive rate of EIA was lower than that of ChIA [0.03% vs. 0.08%, odds ratio 0.33 (95% confidence interval 0.24, 0.45)]. The positive predictive value (PPV) of EIA (89.6%) was significantly higher than that of ChIA (76.1%) (<0.001), reflecting the difference between the two assays. The clinical sensitivities of two assays in this study were 99.64% for EIA and 99.88% for ChIA. CONCLUSION: Caution is needed before shifting from 3rd to 4th generation HIV tests. Since none of these tests are perfect, different geographic and ethnic area probably require different considerations with regard to HIV testing methods, taking into account the local conditions.