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A finite model incorporating microstructure was developed to investigate the thermal shock resistance of TiB2‒B4C composite ceramic cutting tool materials. Numerical simulations were conducted to analyze changes in the transient temperature field and thermal stress field during the thermal shock process. TiB2‒B4C composite ceramic tool materials were fabricated using discharge plasma sintering technology. With different B4C contents, different sintering temperatures and holding times as study variables, optimization of the sintering process parameters and ceramic material components was achieved through testing the mechanical and microscopic morphology of the ceramics. Thermal shock water quenching experiments were performed, and the strength‐decay method was employed to assess the thermal shock resistance of TiB2‒B4C ceramics. The findings indicate that the optimal sintering conditions are temperature of 1700°C and holding time of 5 min. The TiB2‒B4C ceramic material containing 20 vol% B4C exhibits superior comprehensive mechanical properties and thermal shock resistance, and its relative density, fracture toughness, hardness, and flexural strength were 99.3%, 6.8 MPa m1/2, 22.8 GPa, and 598 MPa, respectively. The critical thermal shock temperature difference falls within the range of 400°C‒500°C. [ABSTRACT FROM AUTHOR]

Here, an approach to produce a hierarchical porous Fe‐N‐C@TABOH catalyst with densely accessible high intrinsic active FeNx sites is proposed. The method involves a single‐step pyrolysis of Zn/Fe‐zeolitic imidazolate framework (Zn/Fe‐ZIF‐H) with tetrabutylammonium hydroxide (TABOH) micelles, which is obtained by utilizing TABOH as a structural template and electronic mediator at room temperature for a brief duration of 16 min. Notably, the yield of Zn/Fe‐ZIF‐H is 3.5 times that of Zn/Fe‐ZIF‐N prepared by conventional method. Results indicate that in addition to expediting synthesis and increasing yield of the Zn/Fe‐ZIF‐H, the TABOH induces a hierarchical porous structure and fosters the formation of more and higher intrinsic active FeNx moieties in Fex‐N‐C@TABOH, showing that TABOH is a multifunctional template. Crucially, the increased mesoporosity/external surface area and optimized microenvironment of Fe‐N‐C@TABOH significantly enhance ORR activity by facilitating the formation of high intrinsic active FeNx sites, increasing accessible FeNx sites, and reducing mass transfer resistance. Through structure tailoring and microenvironment optimization, the resulting Fe‐N‐C@TABOH exhibits superior ORR performance. DFT calculation further validates that the synergistic effect of these two factors leads to low ORR barrier and optimized *OH adsorption energy. This study underscores the importance of structure and electronic engineering in the development of highly active ORR catalysts. [ABSTRACT FROM AUTHOR]

Summary: Wood formation, which occurs mainly through secondary xylem development, is important not only for supplying raw material for the 'ligno‐chemical' industry but also for driving the storage of carbon. However, the complex mechanisms underlying the promotion of xylem formation remain to be elucidated. Here, we found that overexpression of Auxin‐Regulated Gene involved in Organ Size (ARGOS) in hybrid poplar 84 K (Populus alba × Populus tremula var. glandulosa) enlarged organ size. In particular, PagARGOS promoted secondary growth of stems with increased xylem formation. To gain further insight into how PagARGOS regulates xylem development, we further carried out yeast two‐hybrid screening and identified that the auxin transporter WALLS ARE THIN1 (WAT1) interacts with PagARGOS. Overexpression of PagARGOS up‐regulated WAT1, activating a downstream auxin response promoting cambial cell division and xylem differentiation for wood formation. Moreover, overexpressing PagARGOS caused not only higher wood yield but also lower lignin content compared with wild‐type controls. PagARGOS is therefore a potential candidate gene for engineering fast‐growing and low‐lignin trees with improved biomass production. [ABSTRACT FROM AUTHOR]

Introduction: Triptolide (TP), a natural product derived from the herbal medicine Tripterygium wilfordii, exhibits potent immunosuppressive activity. However, the mechanisms underlying its effects in rheumatoid arthritis remain incompletely understood. Methods: Collagen‐induced arthritis (CIA) model was induced in Sprague−Dawley rats by immunization with bovine type II collagen, and TP was administrated as treatment. The therapeutic effect of TP was evaluated based on paw swelling, histopathology, and serum levels of inflammatory factors. Exosomes isolated from rat serum were characterized by transmission electron microscopy, dynamic light scattering, and western blot analysis. Proteomic profiling of exosomes was analyzed by direct DIA quantitative proteomics analysis. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes databases were employed for enrichment analysis related to molecular function, biological processes, and signaling pathways. Western blot analysis was used to analyze differentially expressed proteins. Results: TP treatment ameliorated arthritic phenotypes in CIA rats as evidenced by reduced arthritis score, paw swelling, pathological injury severity scores, and serum levels of inflammatory cytokines. The proteomic analysis revealed that TP treatment significantly inhibited complement and coagulation cascades, interleukin‐17 signaling pathway, and cholesterol metabolism, which were reactivated in CIA rats. Importantly, lipocalin 2 (LCN2) and myeloperoxidase (MPO) levels were markedly upregulated in the CIA group but suppressed upon TP administration. Furthermore, in synovial tissues, LCN2 and MPO expression levels were also elevated in the CIA group but decreased following TP treatment. Conclusion: Our findings demonstrate that TP alleviates CIA, possibly through modulation of exosomal LCN2 and MPO proteins. [ABSTRACT FROM AUTHOR]

Background: Stanford type B aortic dissection (TB‐AD) is a life‐threatening vascular condition with high rates of morbidity and mortality. Currently, thoracic endovascular aortic repair (TEVAR) is widely performed to treat TB‐AD, and some studies have analyzed the influence of stents on hemodynamics using computational fluid dynamics (CFD) models. However, the accuracy of TB‐AD simulation models are not satisfactory, they are often constructed as a regular ideal model. Furthermore, it is unclear which tear should be closed for the best treatment when there are multi entry tears. Purpose: The aims of this paper were to provide an assessment method for the selection of the surgical closure location for type B aortic dissection. Five 3D models of multiple entry tears in type B aortic dissection were produced using real patient computed tomography (CT) images to perform hemodynamic analyses of flow velocity streamlines, wall pressure, and wall shear stress. Methods: A Boolean operation was adopted to establish 3D models with multiple entry tears in type B aortic dissection based on patient‐specific CT images. The Mimics and Ansys plug‐in The Integrated Computer Engineering and Manufacturing code for Computational Fluid Dynamics (ICEM CFD) software were applied to mesh the 3D models. The flow velocity streamlines, wall pressures, and wall shear stresses were then analyzed in the finite element analysis software Fluent. Five 3D models were produced to compare the hemodynamic characteristics of different entry tear numbers, as well as the changes of different closure positions before and after closure. Results: The false lumen of the model with two entry tears had a higher wall pressure than that of model with multiple entry tears, which may tend to squeeze the true lumen and expand the false lumen. The load distribution of the vessel in the model with multiple entry tears had a more balanced flow velocity, and its wall pressure and shear stress were lower than that of model with two entry tears. For aortic dissection with two entry tears, the closure of the proximal entry tear was recommended, which helped to isolate and thrombose the false lumen, thereby improving the blood supply function of the true lumen. Because the postoperative vascular flow velocity and mechanical load performance of the vascular wall were still higher than those of normal blood vessels, the postoperative blood vessels remained pathological, and TEVAR did not restore the blood vessels to their original healthy state. Conclusions: Type B aortic dissection with two entry tears tend to squeeze the true lumen and expand the false lumen, resulting in a new entry tear and deterioration into multiple entry type B aortic dissection. The model of the vessel with multiple entry tears had a more balanced distribution in flow velocity and a smaller wall pressure and shear stress than that of the vessel with two entry tears. The closure of the proximal entry tear was considered an ideal solution for type B aortic dissection with two entry tears. [ABSTRACT FROM AUTHOR]

Single metal atom isolated in nitrogen‐doped carbon materials (MNC) are effective electrocatalysts for oxygen reduction reaction (ORR), which produces H2O2 or H2O via 2‐electron or 4‐electron process. However, most of MNC catalysts can only present high selectivity for one product, and the selectivity is usually regulated by complicated structure design. Herein, a carbon black‐supported CoNC catalyst (CB@CoNC) is synthesized. Tunable 2‐electron/4‐electron behavior is realized on CB@Co‐N‐C by utilizing its H2O2 yield dependence on electrolyte pH and catalyst loading. In acidic media with low catalyst loading, CB@CoNC presents excellent mass activity and high selectivity for H2O2 production. In flow cell with gas diffusion electrode, a H2O2 production rate of 5.04 mol h−1 g−1 is achieved by CB@CoNC on electrolyte circulation mode, and a long‐term H2O2 production of 200 h is demonstrated on electrolyte non‐circulation mode. Meanwhile, CB@CoNC exhibits a dominant 4‐electron ORR pathway with high activity and durability in pH neutral media with high catalyst loading. The microbial fuel cell using CB@CoNC as the cathode catalyst shows a peak power density close to that of benchmark Pt/C catalyst. [ABSTRACT FROM AUTHOR]

Horizontal wells with a slim hole (HW‐SH), characterized by high productivity, high environmental protection, and low cost are gradually being introduced into oil and gas extraction processes in high‐temperature and high‐pressure formations. However, the HW‐SH annulus is narrow, and the distributions of temperature and pressure in the wellbore are very different from those of conventional horizontal wells. Furthermore, the mud properties change under the influence of high temperature and pressure. In this study, a numerical model of the transient temperature‐pressure coupling field in an HW‐SH wellbore was developed based on high‐temperature and high‐pressure performance tests of mud, combined with the characteristics of a narrow annulus in HW‐SH. Subsequently, the effects of the ground temperature gradient, displacement, drill pipe speed, annulus size, and joint size on the temperature‐pressure coupling field were analyzed. Measured data from the HW‐SH drilled in the Mahu field in China were used to validate the developed model. The results showed that the ground temperature had a significant effect on the mud density and rheological properties. As the temperature increased, the mud density decreased, and its rheological properties improved. Although pressure also has a large effect on density, it has a negligible effect on the rheological properties of the mud. The coupled temperature‐pressure field model for HW‐SH considering the effects of the temperature and narrow annulus can predict the annulus temperature and pressure with an accuracy of up to 97%. The ground temperature gradient has the greatest influence on the HW‐SH annular temperature, larger than that of the displacement. In addition, the annular size, rotation speed of the drill pipe, and joint size have almost no influence on the annular temperature. Compared to those of conventional horizontal wells, the rotational speed, annulus size, and joint size of the HW‐SH have a greater impact on the annulus pressure. [ABSTRACT FROM AUTHOR]

Compared with conventional drilling methods, the method of drilling horizontal wells with a slim hole (HW‐SH) has advantages, such as high productivity, environment‐friendliness, and low costs. However, during the drilling process, the narrow annulus may become blocked, which may lead to an increase in the annulus pressure if the wellbore is not clean. This often leads to serious drilling accidents, such as sticking and leaking formations. Many models have been used to study the cutting transport law in an annulus, but the influence of drill‐pipe rotation on cutting transport is often ignored and weakened in these models. None of the existing models can effectively simulate the cutting transport law of an entire well section. Therefore, using these models to predict the cutting transport law in the annulus of the HW‐SH will cause significant errors. In this study, the authors first establish a pipeline model of the same size as the on‐site annulus using computational fluid dynamics (CFD). Subsequently, a one‐dimensional (1D) two‐layer model that uses three correction factors to express the influence of drill‐pipe rotation on cutting transport and annulus pressure loss is developed. Finally, the parameters in the 1D model are calibrated using the CFD simulation results to accurately predict the cutting transport behavior and annular pressure loss. From the calculation results of the annulus cutting quality, annulus section‐cutting concentration, and annulus pressure drop, it was observed that the two algorithms proposed in this study have a high degree of coincidence, thereby confirming the reliability of the model. The 1D model provides close to three‐dimensional (3D) accuracy at a much shorter central processing unit time than the 3D CFD models. In addition, the accuracy of the developed model was verified using the results of an indoor pipeline two‐phase flow experiment conducted at the University of Tulsa, without considering the rotation of the drill pipe. [ABSTRACT FROM AUTHOR]

Herein, a small series of 3‐pyrrolin‐2‐ones was efficiently synthesized through a three‐step Ugi cascade sequence. This method features readily available substrates, simple aqueous workup procedures and good yields, dramatically improving generality of reaction. Importantly, the newly product N‐benzyl‐2‐(3‐(4‐chlorophenyl)‐4‐methyl‐2‐oxo‐2,5‐dihydro‐1H‐pyrrol‐1‐yl)‐2‐phen‐ylacetamide exhibited potent anti‐proliferation in prostate cancer cell line through G1/S cell cycle arrest and targeted in PI3K/AKT/TSC2 signal pathway. [ABSTRACT FROM AUTHOR]

The electrochemical transformation of biomass to high value‐added products is attractive. Herein, Cu sulfide‐mediated in‐situ synthesis of Cu oxide was achieved for efficient electro‐oxidation of biomass derived 5‐hydroxymethylfurfural (HMF) to 2,5‐furandicarboxylic acid (FDCA). The copper foam‐supported Cu sulfide (Cu−S/CF) was in‐situ converted to Cu oxide during the electro‐oxidation process. The in‐situ formed Cu oxide presented high HMF conversion, FDCA yield, and faradaic efficiency in 1 m KOH with HMF concentration up to 100 mm. The oxidation of HMF on Cu oxide started with the formation of high‐valence Cu species with the assistance of OH−, which then oxidized HMF spontaneously. An anion exchange membrane (AEM) electrolyzer with Cu−S/CF as the anode was assembled to continuously produce FDCA with H2 generation at the cathode. The AEM electrolyzer ran stably for 60 h with FDCA content higher than 85 % at a cell voltage between 1.50 and 1.60 V. [ABSTRACT FROM AUTHOR]

Calsequestrin 1 (CASQ1) is the most crucial Ca2+ binding protein localized in the sarcoplasmic reticulum (SR) of skeletal muscle. With high capacity and low affinity for Ca2+, CASQ1 plays a significant role in maintaining a large amount of Ca2+ necessary for muscle contraction. However, only five mutations in CASQ1 have been identified to date. Here, we report a 42‐year‐old Chinese female patient who presented with a 12 years history of slowly progressive upper limb weakness, predominantly affecting distal muscles, which was uncommon comparing to other CASQ1‐related patients. Next‐generation sequencing (NGS) analysis revealed a novel heterozygous mutation (c.766G > A, p.Val256Met) in CASQ1. Functional studies confirmed the likely pathogenicity of this variant. Muscle histopathology revealed rare optically empty vacuoles in myofibers and atypical eosinophilic granules in the cytoplasm, which has not been observed before. We also performed a literature review on all the pathogenic mutations in CASQ1 and summarized their genetic and clinical characteristics. This is the first report on CASQ1‐related myopathy from China, further expanding the mutation spectrum of CASQ1 gene and provides new insights into the function of CASQ1. [ABSTRACT FROM AUTHOR]

Sepsis is a public cause of death in intensive care unit patients. Probiotics were widely used to increase the survival rate of sepsis by a series of clinical research. The purpose of this research was to investigate the therapeutic effects of Lactobacillus johnsonii 6084 in septic mice. Sepsis mouse model was induced by LPS treatment. The influence of L. johnsonii 6084 on the protection of organ injury induced by sepsis was explored. Moreover, the composition of gut microbiota was studied to clarify the mechanism of L. johnsonii 6084 therapeutic effect on sepsis. L. johnsonii 6084 treatment could conspicuously decrease the mortality and organ injury of sepsis. The reduction of gut microbial diversity and richness in septic mice were moderated by the administration of 6084. The abundance of Bacteroidetes and Proteobacteria were change by LPS treatment while restored by L. johnsonii 6084. To conclude, probiotic 6084 may has optimistic result on reducing mortality of sepsis through rebalancing gut microbiota. [ABSTRACT FROM AUTHOR]

Sand deposition in the wellbore is one of the most common problems in oil–gas and hydrate exploitation work. A detailed understanding of the migration characteristics of the sand bed and accurate prediction of the starting velocity of the sand bed are key aspects of effective sand carrying. Therefore, this study conducted a large‐scale outdoor gas–water–sand three‐phase flow experiment. The effects of critical factors such as flow pattern, sand size, sand bed height, and pipe inclination angle on sand bed startup velocity and migration were studied experimentally. The experimental results indicated that during the startup process of the sand bed, sand particles exhibited three states: rolling, jumping, and suspension. During the experiment, the sand bed morphology included a static bed, rolling bed, jumping bed, and suspension bed. Compared to a stratified flow, intermittent flow and agitated flow were more beneficial for the startup velocity of sand beds. An increase in pipe inclination also reduced the starting velocity of the sand bed. With an increase in sand size, the startup velocity of the sand bed increased correspondingly. However, there was no significant influence on the migration morphology of the sand bed. Additionally, the greater the thickness of the sand bed, the lower the starting velocity of the sand bed. Based on the stress states of sand grains, in combination with experimental data, this study used least‐squares estimation to establish a prediction model for the startup velocity of sand beds. The model prediction results were in good agreement with the experimental data. This study will provide a basis for predicting the startup velocity of sand beds during the gas–liquid two‐phase sand‐carrying process. [ABSTRACT FROM AUTHOR]

The Yinggehai Basin (YGH) in the South China Sea is a Cenozoic, high‐temperature, and high‐pressure basin. Exploration and development of natural gas resources in the YGH show that owing to the diapir structures make the formation pressure system is complex, overpressure characteristics are obvious, prediction is difficult, and spatial distribution is irregular, which severely restricts the development of natural gas. To evaluate the influence of diapir structures on the formation and distribution of overpressure, we compared and analyzed the ancient and modern geothermal temperatures, organic matter maturity, clay mineral evolution, burial depth, and pressure coefficient in the diapir and nondiapir zones of the YGH. The results showed that of the diapir structures in the YGH occurred in the following order: Uplift–spiking–piercing–depositing. The Dongfang area is dominated by low‐amplitude turtle‐back diapir structures with weak energy, whereas the Ledong area is dominated by high‐amplitude spiked diapir structures with strong energy, both of which pressurize the upper formation. The Changnan area is dominated by high‐amplitude pierced/depositing diapirs with strong energy, which can relieve pressure. The influence of the diapir and its associated structures on the formation of overpressure can be attributed to the transport of the diapir body and the associated fault‐fracture system and the local thermal effect caused by the upwelling of hot fluids. Under the influence of the diapir structure, the overpressure top surface of the basin was shallower. According to the degree of influence and intensity of the diapir structure, variations in formation pressure coefficient with depth can be divided into four evolution modes: constant pressure, slow pressurization, "Z" pressurization, and "S" pressurization types. This study provides some guidance and references for the identification and accurate prediction of the overpressure formation mechanism in basins containing diapirs, and helps in formulating efficient drilling and production plans. [ABSTRACT FROM AUTHOR]

Formation pressure is the most fundamental data in oil and gas drilling and production; it has an important position in the entire cycle of oil and gas extraction. However, most current prediction methods are limited to parametric methods with fixed models; such that the accuracy does not meet requirements. This is especially true for deeper layers of marine sedimentary basins where the safety density window is extremely narrow. In this study, we propose a novel method to predict pore pressure using machine learning techniques. For the first time, the effective stress (direct output variable) was accurately predicted by a combination of four input variables (2900 sets of data, of which 90% is the training subset and 10% is the testing subset), including longitudinal velocity, porosity, mud content, and density. As such, an accurate prediction of the formation pressure was achieved based on the effective stress theorem. The performance of machine learning techniques was verified by comparing and analyzing the prediction results with traditional parametric single and multivariate models; whereby the best algorithm was chosen by structural optimization and comparative analysis of five algorithms (multilayer perceptron neural network, radial basis neural network, support vector machine, random forest, and gradient boosting machine). Compared with the methods based on parametric one‐dimensional and multivariate models, the machine learning‐based method was determined to possess high accuracy, adequate self‐adaptation, and high fault tolerance (D2 = 0.9981, RMSE = 0.00718 g/cm3). Moreover, the multilayer perceptual neural network algorithm outperformed other machine learning algorithms in terms of goodness of fit, generalization, and prediction accuracy, with D2 = 0.9981 and RMSE = 0.00709 g/cm3. The formation pressure prediction model developed in this study is not affected by the mechanical depositional environment and is applicable to sandy mudstone formations, such that it can be a useful and highly accurate alternative to the traditional formation pressure prediction methods with fixed parameter forms. [ABSTRACT FROM AUTHOR]

Inverse synthetic aperture lidar (ISAL) has overcome the optical diffraction limit and realized radar imaging with centimeter‐level resolution at ultra‐long distances. Taking a two‐dimensional Gaussian rough surface as an example, a method for calculating the scattered echo under the Kirchhoff approximation based on two‐dimensional Fourier transform is proposed. ISAL imaging of planar rough targets (square and circular plates) is realized using the intensity and phase information of the scattered echo. Moreover, the ISAL imaging of large rough convex targets (cone) is obtained through a coordinate transformation, and the influence of different rough targets on ISAL imaging is analyzed, revealing that as the roughness decreases, the proportion of scattering produced by coherent scattering increases, resulting in a sharper target edge, whereas increasing target roughness leads to the image energy distribution becoming more uniform. [ABSTRACT FROM AUTHOR]

Aim: Exosomes has been shown to be involved in the regulation of cancer progression. However, the role of exosome miR‐134‐5p in breast cancer (BC) progression is unclear. Methods: Exosomes were extracted from BC cells (MCF‐7 and MDA‐MB‐231) using differential centrifugation and were observed by transmission electron microscope (TEM). The protein levels of exosome markers, apoptosis markers, Rho GTPase activating protein 1 (ARHGAP1, an important oncogene in BC) and phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (AKT) markers were detected by western blot (WB) assay. Quantitative real‐time PCR was used to measure the expression levels of miR‐134‐5p and ARHGAP1. Cell cycle and apoptosis, colony number, viability, migration, and invasion were determined by flow cytometry, colony formation assay, MTT assay, and transwell assay, respectively. The interaction between miR‐134‐5p and ARHGAP1 was confirmed using a dual‐luciferase reporter assay. Xenograft models were constructed to verify the role of exosome miR‐134‐5p in BC tumor growth in vivo. Results: MiR‐134‐5p was lowly expressed in BC cells and in the exosomes of BC cells. Overexpressed exosome miR‐134‐5p suppressed the proliferation, migration, invasion, and promoted the apoptosis of BC cells. ARHGAP1 was a target of miR‐134‐5p, and its silencing could inhibit BC progression. In addition, ARHGAP1 overexpression could reverse the negative regulation of miR‐134‐5p on BC progression. MiR‐134‐5p could target ARHGAP1 to inhibit the activity of PI3K/AKT pathway. Exosome miR‐134‐5p overexpression could suppress BC tumor growth via targeting ARHGAP1 in vivo. Conclusion: Exosome miR‐134‐5p restrained BC progression through regulating ARHGAP1/PI3K/AKT signaling pathway, suggesting that miR‐134‐5p might be a therapeutic target for BC. [ABSTRACT FROM AUTHOR]

Characterizing long‐term prescription data is challenging due to the time‐varying nature of drug use. Conventional approaches summarize time‐varying data into categorical variables based on simple measures, such as cumulative dose, while ignoring patterns of use. The loss of information can lead to misclassification and biased estimates of the exposure‐outcome association. We introduce a classification method to characterize longitudinal prescription data with an unsupervised machine learning algorithm. We used administrative databases covering virtually all 1.3 million residents of Manitoba and explicitly designed features to describe the average dose, proportion of days covered (PDC), dose change, and dose variability, and clustered the resulting feature space using K‐means clustering. We applied this method to metformin use in diabetes patients. We identified 27,786 metformin users and showed that the feature distributions of their metformin use are stable for varying the lengths of follow‐up and that these distributions have clear interpretations. We found six distinct metformin user groups: patients with intermittent use, decreasing dose, increasing dose, high dose, and two medium dose groups (one with stable dose and one with highly variable use). Patients in the varying and decreasing dose groups had a higher chance of progression of diabetes than other patients. The method presented in this paper allows for characterization of drug use into distinct and clinically relevant groups in a way that cannot be obtained from merely classifying use by quantiles of overall use.Distinction between stable and varying patterns of metformin use. [ABSTRACT FROM AUTHOR]

Manipulating the molecular aggregation behavior plays an important role in many fields. Here, by manipulating the molecular aggregation behavior, it is the first time that the same benzoxazine molecule is used to synthesize two kinds of gel materials with underwater superoleophobic and underoil superhydrophobic properties. Meanwhile, these materials are successfully used to separate surfactant‐stabilized water‐in‐oil and oil‐in‐water emulsions. The relationship between the surface properties and molecular aggregation behavior is analyzed. Controlling molecular aggregation behavior is essential to allow the molecules reach the most stable state spontaneously (where the Gibbs free energy is the smallest under constant temperature and pressure) under different environmental conditions. This research may open a new pathway to construct different functional materials by using the same molecule, and also provide a basis for other fields to achieve various applications by manipulating the molecular aggregation behaviors. [ABSTRACT FROM AUTHOR]

It is a great challenge to fabricate electrode with simultaneous high activity for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). Herein, a high‐performance bifunctional electrode formed by vertically depositing a porous nanoplate array on the surface of nickel foam is provided, where the nanoplate is made up by the interconnection of trinary Ni–Fe–Mo suboxides and Ni nanoparticles. The amorphous Ni–Fe–Mo suboxide and its in situ transformed amorphous Ni–Fe–Mo (oxy)hydroxide acts as the main active species for HER and OER, respectively. The conductive network built by Ni nanoparticles provides rapid electron transfer to active sites. Moreover, the hydrophilic and aerophobic electrode surface together with the hierarchical pore structure facilitate mass transfer. The corresponding water electrolyzer demonstrates low cell voltage (1.50 V @ 10 mA cm−2 and 1.63 V @ 100 mA cm−2) with high durability at 500 mA cm−2 for at least 100 h in 1 m KOH. [ABSTRACT FROM AUTHOR]

In deepwater drilling, accurate prediction of wellbore gas‐liquid two‐phase flow behavior is significant for gas kick detection and well‐control treatment. In this study, a new transient gas‐liquid two‐phase flow model was developed to simulate the wellbore gas‐liquid two‐phase flow during gas kick in deepwater dual‐gradient drilling based on downhole separation. This model accounts for the impact of a sudden change in density on gas‐liquid flow behavior. The transient model was solved using the finite‐difference method. The accuracy and stability of the model were verified using data measured from a full‐scale experimental well. Using this model, the differences in the apparent liquid velocity and the flow rate at the annular outlet during gas kick were compared between deepwater dual‐gradient drilling and conventional single‐gradient drilling. Additionally, the influences of numerous factors on variations in flow rate at the annular outlet were also studied. A new method of early gas kick detection was proposed for deepwater dual‐gradient drilling based on downhole separation. [ABSTRACT FROM AUTHOR]

An omnidirectional antenna with a compact size is presented. The diameter of the proposed antenna is 100 mm and the height is ∼0.1λL (12 mm). It consists of two dipoles and four shorting pins. With this configuration, the impedance bandwidth of the proposed antenna covers 2.4–2.6 GHz. Within the bandwidth, the proposed antenna has a stable bidirectional radiation pattern in the E-plane and the omnidirectional radiation pattern in the H-plane. The geometry of the antenna is investigated and optimised by the ANSYS high-frequency structure simulator. The fabricated antenna is compact enough to be integrated into a communication system. Measured and simulated results are also obtained and compared at the end of this work. [ABSTRACT FROM AUTHOR]

Summary: Verticillium dahliae is a broad host‐range pathogen that causes vascular wilts in plants. Interactions between three hosts and specific V. dahliae genotypes result in severe defoliation. The underlying mechanisms of defoliation are unresolved.Genome resequencing, gene deletion and complementation, gene expression analysis, sequence divergence, defoliating phenotype identification, virulence analysis, and quantification of V. dahliae secondary metabolites were performed.Population genomics previously revealed that G‐LSR2 was horizontally transferred from the fungus Fusarium oxysporum f. sp. vasinfectum to V. dahliae and is exclusively found in the genomes of defoliating (D) strains. Deletion of seven genes within G‐LSR2, designated as VdDf genes, produced the nondefoliation phenotype on cotton, olive, and okra but complementation of two genes restored the defoliation phenotype. Genes VdDf5 and VdDf6 associated with defoliation shared homology with polyketide synthases involved in secondary metabolism, whereas VdDf7 shared homology with proteins involved in the biosynthesis of N‐lauroylethanolamine (N‐acylethanolamine (NAE) 12:0), a compound that induces defoliation. NAE overbiosynthesis by D strains also appears to disrupt NAE metabolism in cotton by inducing overexpression of fatty acid amide hydrolase.The VdDfs modulate the synthesis and overproduction of secondary metabolites, such as NAE 12:0, that cause defoliation either by altering abscisic acid sensitivity, hormone disruption, or sensitivity to the pathogen. [ABSTRACT FROM AUTHOR]

Hyperspectral images are mixtures of spectra of materials in a scene. Accurate analysis of hyperspectral image requires spectral unmixing. The result of spectral unmixing is the material spectral signatures and their corresponding fractions. The materials are called endmembers. Endmember extraction equals to acquire spectral signatures of the materials. In this study, the authors propose a new hyperspectral endmember extraction algorithm for hyperspectral image based on QR factorisation using Givens rotations (EEGR). Evaluation of the algorithm is demonstrated by comparing its performance with two popular endmember extraction methods, which are vertex component analysis (VCA) and maximum volume by householder transformation (MVHT). Both simulated mixtures and real hyperspectral image are applied to the three algorithms, and the quantitative analysis of them is presented. EEGR exhibits better performance than VCA and MVHT. Moreover, EEGR algorithm is convenient to implement parallel computing for real‐time applications based on the hardware features of Givens rotations. [ABSTRACT FROM AUTHOR]

Non‐Hodgkin lymphomas (NHL) are a group of cancers with highly heterogeneous biology and clinical features. Statins are increasingly prescribed to prevent cardiovascular diseases. Early evidence shows a preventive effect of statins for some cancers, but their effect on NHL risk is unclear. We conducted a population‐based nested case–control study involving 5,541 NHL cases and 27,315 controls matched for gender, age, place of residence and length of period of available prescription drug data. We assessed the use of statins prior to diagnosis (excluding the 12 months prior to the index date). We used conditional logistic regression models to estimate odds ratio (OR) and 95% confidence interval (CI) for use of any statin, adjusting for medical conditions, number of family physician visits for 5 years prior to index date, healthcare utilization, income and use of other medications. Over one‐quarter of cases and controls were prescribed statins. Ever‐use of any statin was associated with lower risk of Total NHL (OR = 0.82, 95% CI 0.76–0.89) and of certain subtypes including diffuse large B‐cell lymphomas (DLBCL, OR = 0.77, 95% CI 0.65–0.92), plasma cell neoplasms (PCN, OR = 0.76, 95% CI 0.63–0.91) and other B‐cell NHL (0.75, 0.59–0.95). Analysis by statin type suggested that the association was limited to high potency statin and lipophilic statin users. No clear duration or dose–response relationships were observed. Our findings provide evidence that statin use can reduce the risk of DLBCL and plasma cell lymphomas, but not other NHL types. Further studies are warranted to verify these associations and to examine the biological mechanisms. [ABSTRACT FROM AUTHOR]

Abstract: In nature, the superhydrophobic surfaces are almost in situ grown on its bulk phase under special environment. However, it is still a doubt how the bulk phase composition and external environment influence the structures and properties of in situ growth surfaces. To investigate the influence, a strategy is devised via using fluorine‐free benzoxazine as matrix model, selecting different metal chlorides to change the bulk phase composition of the matrix and utilizing different curing media to control the interface growth environment. It is found interestingly that the properties of in situ growth surfaces depend strongly on its bulk phase composition and external environment, and the superhydrophobic surface with controlled adhesion could be synthesized by in situ polymerization through one‐step curing and regulation of the bulk phase composition and growth environment. Moreover, the in situ growth superhydrophobic surface with controlled adhesion has high thermal stability, chemical stability, mechanical stability, and persistent stability. These findings not only show a unique idea for fabricating superhydrophobic surfaces with controlled adhesion, but also provide useful enlightenment for preparation and understanding of heterogeneous catalysts, sensors, and drag reducing materials. [ABSTRACT FROM AUTHOR]

Abstract: Well‐controlled synthesis of ethynyl‐functionalized poly(3‐hexylthiophene) (P3HT) is crucial for preparation of block copolymers containing the P3HT segment by means of click coupling reaction. A well‐known chain end modification method, in which Kumada–Tamao catalyst‐transfer polymerization is quenched with ethynylmagnesium chloride, under various conditions is re‐examined, but in all cases not only P3HT with an ethynyl group at one end but also P3HT di‐ethynylated at both ends is obtained. Accordingly, Sonogashira coupling reaction of P3HT having H/Br ends with trimethylsilylacetylene is tried, followed by removal of the trimethylsilyl group, and it is found that this protocol affords exclusively P3HT with an ethynyl group at one end. This post end‐modification method is applied to the synthesis of an amphiphilic diblock copolymer of P3HT and poly(2‐ethyl‐2‐oxazoline) (PEtOx) by means of click reaction between ethynylated P3HT and PEtOx with an azide group at one end, and the product is confirmed to be free from contamination with triblock copolymer. Micellization of this block copolymer is confirmed in tetrahydrofuran (THF)/water and THF/methanol mixtures. [ABSTRACT FROM AUTHOR]

* Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce). * Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed. * The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer. * Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen. [ABSTRACT FROM AUTHOR]

Background and Aim The herpes virus entry mediator (HVEM) network has become new directions in targeting novel checkpoint inhibitors for cancer therapy. However, the changes of membrane-bound HVEM (mHVEM) and soluble HVEM (sHVEM) in hepatocellular carcinoma (HCC) are not fully understood. This study aims to study the changes of mHVEM and sHVEM in HCC patients. Methods Serum samples were collected from 65 HCC patients, from which sHVEM levels were examined by enzyme-linked immunosorbent assay. Expressions of mHVEM on peripheral lymphocytes from 20 HCC patients were determined using flow cytometry, and associations between mHVEM on T and B cells were analyzed. Results The levels of mHVEM were downregulated on peripheral lymphocytes in HCC patients, with a strong positive correlation between mHVEM expression on T and B cells. In contrast, the levels of soluble HVEM were upregulated in the serum of HCC patients. Furthermore, we found that the increase in sHVEM level was correlated with advanced stages HCC. Conclusion Our data demonstrated paradoxical changes of membrane and soluble HVEM in the peripheral blood of HCC patients for the first time. These data supported the notion that roles of HVEM are likely to be immunosuppressive rather than activating tumor immunity. Future studies are warranted to further explore the translational values of mHVEM and sHVEM in peripheral blood as diagnostic markers and therapeutic targets. [ABSTRACT FROM AUTHOR]

Complexation of racemic 2,6-helic[6]arene 1 and its hexamethyl-substituted derivative 2 with quaternary ammonium salts, N-heterocyclic salts, and tetracyanoquinodimethane have been described in detail. It was found that host 2 could form stable complexes with acetyl choline, thiaacetyl choline, N, N, N-trimethylbenzenammonium salt, pyridinium, and 4,4′-bipyridinium salts in solution and/or in the solid state. The unsubstituted macrocycle 1 showed more significant complexation with the widely tested quaternary ammonium salts and N-heterocyclic salts, and exhibited stronger complexation towards the guests than its derivative 2. Moreover, it was found that macrocycle 1 and its derivative 2 could also complex with neutral electron-deficient tetracyanoquinodimethane (TCNQ), and the association constants were determined to be 2840±94 and 1358±46 m−1, respectively. These results could make this new macrocycle and its derivatives find wide applications in the design and construction of functional supramolecular assemblies. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate the functional role of G protein-coupled receptor 30 (GPR30) in the epididymis. We found that GPR30 is expressed in the epithelium of the immature rat epididymis and is involved in chloride secretion into the caudal epididymis lumen. The short-circuit current (Isc) experiments showed that in primary cultured caudal epididymis epithelium, activation of GPR30 by its specific agonist G1 induced a mono-phasic current increase, and G15, the specific antagonist of GPR30, could completely inhibit the current induced by G1. The G1-induced Isc was largely blocked by application of the non-specific chloride channel inhibitor diphenylamine-dicarboxylic acid (DPC), or by the cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor CFTRinh-172, suggesting that the current was mainly mediated through CFTR. In addition, after stimulating GPR30 by G1, the intracellular concentration of cAMP in the epithelium was significantly increased, indicating that the cAMP signal pathway is involved and could be responsible for the CFTR activation. Finally, to further investigate the function of GPR30 in vivo, G15 was administrated into rats subcutaneously. The osmotic pressure of the micro perfusion solution from epididymis was measured and the sperms were collected. Results showed that there was an osmotic pressure increase of the perfusion solution from G15 treated rats. When the GPR30 was inhibited by G15 endogenously, the motility of sperms decreased. Our data demonstrated that GPR30 is involved in the formation of caudal epididymis fluid micro-environment thus affecting sperm motility. [ABSTRACT FROM AUTHOR]

A new class of chiral macrocyclic arene composed of three chiral 2,6-dihydroxyltriptycene subunits bridged by methylene groups was designed and synthesized. Structural studies showed that the macrocyclic molecule adopts a hex-nut-like structure with a helical chiral cavity and highly fixed conformation. Efficient resolution was achieved through the introduction of chiral auxiliaries to give a couple of enantiopure macrocycles, which exhibited high enantioselectivity towards three pairs of chiral compounds containing a trimethylamino group. [ABSTRACT FROM AUTHOR]

The depressing oxygen reduction reaction (ORR) performance has impeded the commercialization of proton exchange membrane fuel cells. As a surface-sensitive reaction, the surface structure of the electrocatalyst has a crucial impact on the ORR. Herein, Pt nanoparticle surfaces were modified with the aid of Ag, which was deposited on the surface of Pt nanoparticles and was etched away through cyclic voltammetry (CV). After surface modification, the step density of the Pt nanoparticles was observed to decrease, according to high-resolution transmission electron microscopy images, which could contribute to the positive shift of the Pt 4f binding energy and the improved ability to prevent Pt from being oxidized, as seem by using X-ray photoelectron spectroscopy. Furthermore, the peak potential increase for the surface metal-oxide reduction during CV was consistent with the impact of the step density reduction. After surface modification, the Pt nanoparticles showed improved ORR performance, according to half-cell tests. At the atomic scale, the decrease in the number of low-coordination atoms on the surface steps, which exhibit stronger interactions with Oads/OHads compared with atoms on terraces, could lead to the enhanced ORR performance. [ABSTRACT FROM AUTHOR]

One-handed helical polyphenylacetylenes having achiral amino alcohol moieties, but no chiral side groups, were synthesized by the helix-sense-selective copolymerization of an achiral phenylacetylene having an amino alcohol side group with a phenylacetylene having two hydroxyl groups. Since the resulting helical copolymers were successfully utilized as chiral ligands for the of benzaldehyde with diethylzinc, we can conclude that the main-chain chirality based on the one-handed helical conformation is useful for the chiral of an for the first time. The of the reaction were controlled by the optical purities of the helical polymer ligands. In addition, the polymer ligands could be easily recovered by precipitation after the reaction. Chirality 27:454-458, 2015. © 2015 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Background Interleukin-6/IL-12 family cytokines play a key role in inflammatory diseases via their effects on the differentiation or regulation of T helper cells. Aims The aim of this study was to determine the role of interleukin-27 ( IL-27) and its association with helper T cells in hepatitis B virus ( HBV)-infected patients. Methods Samples were assessed from 51 HBV-infected patients [28 chronic hepatitis B ( CHB) subjects and 23 acute-on-chronic liver failure ( ACLF) subjects] and 18 normal controls ( NC). Serum IL-27 levels were examined by enzyme-linked immunosorbent assay. Circulating helper T cells were determined using flow cytometry and associations between IL-27 expression and helper T cells were analysed. Results Serum IL-27 levels rose in HBV-infected patients (502.88 ± 23.35 pg/ml) compared to ( NC, 277.14 ± 23.96 pg/ml, P < 0.0001). Furthermore, it significantly increased in patients with ACLF (587.90 ± 33.08 pg/ml) when compared with CHB (433.04 ± 26.57 pg/ml, P = 0.001). However, no statistically significant differences were observed between IL-27 and the presence of HBeAg. High levels of IL-27 then positively correlated with Tbil levels ( r = 0.401, P = 0.004), but negatively associated with prothrombin time activity levels ( r = −0.496, P < 0.001), and a slightly negative correlation trend with HBV- DNA loads ( r = −0.228, P = 0.107) existed in these HBV-infected subjects. Additionally, frequency of circulating interleukin-17-producing CD4+T cells (Th17 cells) increased in HBV-infected patients ( ACLF, mean, 5.39%; CHB, median, 3.12%) as compared to NC subjects (median, 2.22%, P < 0.0001). Moreover, correlation analysis showed that serum IL-27 level was positively associated with circulating Th17 cells ( r = 0.342, P = 0.036). Conclusion These results provided evidence that IL-27 was positively correlated with Th17 cells commitment, and may exerted a proinflammatory effect in the development of liver injury in HBV-infected patients. [ABSTRACT FROM AUTHOR]

A novel phenylacetylene ( 1) having two hydroxyl groups and a chiral pinanyl group together with the other three related phenylacetylenes has been synthesized and (co)polymerized by using an achiral catalytic system. Among the four monomers, only 1 is suitable to the asymmetric-induced polymerization ( AIP). Chiral amplification phenomenon is only observed in the copolymerization of 1 with an achiral phenylacetylene having two hydroxyl groups ( 3). The tight helical cis-cisoidal main chain formed by making intramolecular hydrogen bonds between the hydroxyl groups in the copoly( 1/ 3) enhances the efficiency of chiral induction and as a result chiral amplification phenomenon is observed during the copolymerization. [ABSTRACT FROM AUTHOR]

Background and Aim Although regulatory T cells ( Treg) and interleukin-17-producing CD4 T cells ( Th17) have been demonstrated to play opposing roles in inflammation-associated diseases, their frequency and balance in different stages of hepatitis B virus ( HBV)-related acute-on-chronic liver failure ( ACLF) remain unknown. Methods Fourteen patients with HBV-associated ACLF were studied and defined into different stages according to disease activity. Circulating Th17 cells and Treg cells were analyzed by flow cytometry, and the cytokines were quantitated by enzyme-linked immunosorbent assay. Results were correlated with temporal changes in viral load, disease progression and compared with 30 chronic hepatitis B ( CHB) subjects and 18 healthy subjects. Results We showed a significantly higher frequency of circulating Th17 cells in the remission stage of ACLF when compared with the progression stage, the CHB group, or normal controls. However, the frequency of circulating Treg cells was significantly lower in the remission stage of ACLF when compared with the progression stage or the CHB group. The increase in Th17 cells and concomitant decrease in Treg cells created an imbalance in the remission stage of ACLF patients, which negatively correlated with disease progression. In addition, we showed that ACLF patients in the remission stage had an altered profile of cytokines that regulated the induction of Th17 cells and Treg cells. Conclusions ACLF patients in the remission stage had an imbalance of Th17 to Treg cells, which could be used as a prognostic marker to predict disease progression. This imbalance could play a role in the immunopathogenesis of HBV-related ACLF. [ABSTRACT FROM AUTHOR]

MIF is a proinflammatory cytokine and is implicated in cancer. A higher MIF level is found in many human cancer and cancer-prone inflammatory diseases, including chronic pancreatitis and pancreatic cancer. We tested the hypothesis that MIF contributes to pancreatic cancer aggressiveness and predicts disease outcome in resected cases. Consistent with our hypothesis we found that an elevated MIF mRNA expression in tumors was significantly associated with poor outcome in resected cases. Multivariate Cox-regression analysis further showed that MIF is independently associated with patients' survival (HR = 2.26, 95% CI = 1.17-4.37, p = 0.015). Mechanistic analyses revealed that MIF overexpression decreased E-cadherin and increased vimentin mRNA and protein levels in pancreatic cancer cell lines, consistent with the features of epithelial-to-mesenchymal transition (EMT). Furthermore, MIF-overexpression significantly increased ZEB1/2 and decreased miR-200b expression, while shRNA-mediated inhibition of MIF increased E-cadherin and miR-200b expression, and reduced the expression of ZEB1/2 in Panc1 cells. Re-expression of miR-200b in MIF overexpressing cells restored the epithelial characteristics, as indicated by an increase in E-cadherin and decrease in ZEB1/2 and vimentin expression. A reduced sensitivity to the chemotherapeutic drug, gemcitabine, occurred in MIF-overexpressing cells. Indicative of an increased malignant potential, MIF over-expressing cells showed significant increase in their invasion ability in vitro, and tumor growth and metastasis in an orthotopic xenograft mouse model. These results support a role of MIF in disease aggressiveness, indicating its potential usefulness as a candidate target for designing improved treatment in pancreatic cancer. [ABSTRACT FROM AUTHOR]

Composite films of carbon nanotubes (CNTs) and MgO nanoparticles are fabricated on metal substrates as field emitters by a simple mechanical rubbing method. The field emission properties of the CNT films could be dramatically improved by mixing an optimum proportion (∼7 wt%) of MgO nanoparticles. It lowers the turn-on field to 1.3 V µm−1 and the threshold field to 2 V µm−1, and also increases the field emission stability and uniformity. Such CNTs-MgO films are applied as cathode in ionization vacuum gauges. The gauges, with the advantages of small size and low power consumption, exhibit good measurement linearity in vacuum pressure range from 8 × 10−6 to 2 × 10−2 Pa, and a sensitivity of 0.2 Pa−1. [ABSTRACT FROM AUTHOR]

Titanium oxide (TiO2) nanospheres were synthesized by using cathodic-plasma electrolysis method at low voltage of 70 V. The morphological, componential, and structural characterizations of the nanospheres were carried out in detail by using scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD). It is found the nanospheres mostly have diameters in the range of 20-200 nm, and are in anatase, rutile, and oxygen-deficient phases. The nanospheres exhibit excellent optical absorption covering the wavelength range from 240 to 2600 nm. It is also found that the low voltage during plasma electrolysis could result in more anatase phases of TiO2. The mechanisms responsible for the nanosphere formation and the wide spectral absorption were also discussed. [ABSTRACT FROM AUTHOR]

Store-operated calcium entry (SOCE) is essential for many cellular processes. In this study, we investigated modulation of SOCE by tyrosine phosphorylation in rat epididymal basal cells. The intracellular Ca([Ca]i) measurement showed that SOCE occurred in rat epididymal basal cells by pretreating the cells with thapsigargin (Tg), the inhibitor of sarco-endoplasmic reticulum Ca-ATPase. To identify the role of Ca channels in this response, we examined the effects of transient receptor potential canonical channel blockers 2-aminoethoxydiphenyl borate (2-APB), 1-[β-[3-(4-methoxyphenyl)pro-poxy]-4-methoxyphenethyl]-1H-imidazole hydrochloride(SKF96365), Gd, and non-selective cation channel blocker Ni respectively on SOCE and found that these blockers could inhibit the Ca influx to different extent. Furthermore, we studied the regulation of SOCE by tyrosine kinase pathway. The inhibitor of tyrosine kinase genistein remarkably suppressed the SOCE response, whereas sodium orthovanadate, the inhibitor of tyrosine phosphatase, greatly enhanced it. The results suggest that tyrosine kinase pathway plays a significant role in the initiation of SOCE and positively modulates SOCE in epididymal basal cells. J. Cell. Physiol. 226: 1069-1073, 2011. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Introduction: Optimizing atrial automatic capture verification based on atrial-evoked response (AER) detection requires maximizing the signal artifact ratio (SAR), that is, AER to stimulation artifact (ART). This study evaluated the effect of bipolar atrial lead position on sensed AER, ART, and SAR. Methods and Results: A custom-made external research system (INSIGNIAAC, Boston Scientific Corp. St Paul, MN, USA) was used to perform an automatic voltage step-down atrial pacing protocol at three different right atrial lead positions (A-appendage, L-lateral wall, and S-septal wall) in each studied patient. The atrial pacing and the AER sensing configurations were independent. The pacing was unipolar in an Atip-Can configuration while sensing was in Aring-Indiff. Data from 16 patients (mean age 71.1 ± 9.6 years) and six-lead models from five different manufacturers were analyzed. Study results show that with all lead types, the atrial lead placement had no significant effect on AERmin, ARTmax, and SARmin and only one patient had an SAR that was not sufficient to support successful automatic capture verification at all tested atrial pacing sites. Conclusion: The atrial pacing site has minimal effect on AER sensing when using an independent pace/sense configuration. The leads placed at all tested sites were found to have the parameters sufficient to support the atrial automatic capture verification in all but one patient. [ABSTRACT FROM AUTHOR]

Introduction: This study evaluated an atrial automatic capture verification scheme based on atrial evoked response (AER). Atrial pacing was between Atip and Can (Atip-Can) using different coupling capacitances (CCs). Independent pairs of sensing electrodes between Aring and Vtip (Aring-Vtip) or between Aring and a separate indifferent electrode (Aring-Indiff) were used to reduce pacing-induced afterpotentials. Methods and Results: A custom-made external pacing system was used to perform automatic step-up and step-down pacing (0.1 to 7.1 V at 0.5 msec, step size of 0.1 V) using different CCs (2 or 15 µF). Intracardiac signals from Aring-Indiff and Aring-Vtip were independently recorded and analyzed both in real time and off-line to detect AER. Every paced beat also was visually inspected and compared with surface ECG to verify the captures. With the intracardiac signals properly filtered, AER detection was based on the signal within a window of 12 to 65 msec after the stimulus. Data from 27 patients (4 chronic and 23 acute implantations; age 65.6 ± 13.9 years) were analyzed. Bipolar atrial lead measurements using a standard pacing system analyzer were as follows (mean ± SD): impedance 695 ± 227 Ω, P wave amplitude 4.2 ± 2.3 mV, slew rate 1.1 ± 0.9 V/sec, and pacing threshold at 0.5 msec 1.0 ± 0.5 V. The results with CC = 2 µF showed that of 9,500 atrial paced beats, correct capture verification rates were -99.8% (Aring-Indiff) and 99.4% (Aring-Vtip). Similar results were achieved with CC = 15 µF (99.7% and 99.5%, respectively). Conclusion: AER can be reliably detected using independent pacing (Atip-Can) and sensing (Aring-Vtip or Aring-Indiff) electrodes. Therefore, atrial automatic capture verification by AER detection is feasible. [ABSTRACT FROM AUTHOR]