A case of Arrhythmogenic right ventricular cardiomyopathy without arrhythmias

<p>Abstract</p> <p>Arrhythmogenic right ventricular cardiomyopathy (ARVC) is characterized by recurrent coma, ventricular tachycardias and the replacement of the myocardium with fatty and fibrous tissue. We described a 42-year-old female patient without clinical arrhythmias which was diagnosed as ARVC by magnetic resonance imaging (MRI), but the transvenous endomyocardial biopsy was not specific. The patient received heart transplantation due to her refractory heart failure and the pathology of explanted heart demonstrated typical replacement of fatty and fibrous tissue and piles of infiltrated lymphocytes in myocardial tissue. It is concluded that ARVC might not have any arrhythmias and inflammatory process may be involved in the mechanism of ARVC.</p> <p>Virtual slides</p> <p>The virtual slide(s) for this article can be found here: <url>http://www.diagnosticpathology.diagnomx.eu/vs/6573514507145351</url></p

Drug Discovery Based on Fluorine-Containing Glycomimetics

Glycomimetics, which are synthetic molecules designed to mimic the structures and functions of natural carbohydrates, have been developed to overcome the limitations associated with natural carbohydrates. The fluorination of carbohydrates has emerged as a promising solution to dramatically enhance the metabolic stability, bioavailability, and protein-binding affinity of natural carbohydrates. In this review, the fluorination methods used to prepare the fluorinated carbohydrates, the effects of fluorination on the physical, chemical, and biological characteristics of natural sugars, and the biological activities of fluorinated sugars are presented

Evolution of the Ordovician top boundary and its relationship to reservoirs' development, Ordos Basin

The control of structural evolution on the development of different types of Ordovician reservoirs in the Ordos Basin is discussed by studying the evolution of the Ordovician top boundary in geological times, and the mechanisms of formation and evolution of carbonate reservoirs are examined. The top boundary of the Ordovician is an important sequence boundary in the Ordos Basin. It represents not only the depositional change between lower marine carbonate rocks and upper clastic rocks, but also a depositional break caused by weathering and corrosion from the Late Calidonian to the Early Hercynian. It experienced three great structural changes in the geological history, which influenced the formation and conservation of the Ordovician reservoirs. Difference of lithology of the Ordovician top sequence between the east and west of the basin controlled the type of reservoir space and caused the formation of different reservoirs of corrosive pores. However, the later reversal of the sequence boundary causes the filling of early formed pore space in the eastern basin, and affects the space distribution of effective reservoirs. Key words: Ordos Basin, Ordovician, reservoir, sequence stratigraphy, sequence boundary, pore fillin

A Multi-Level Synergistic Image Decomposition Algorithm for Remote Sensing Image Fusion

International audienc

Spatiotemporal Changes in the Supply and Demand of Ecosystem Services in China&rsquo;s Huai River Basin and Their Influencing Factors

An imbalance between the supply and demand of ecosystem services can cause ecological problems. By determining the spatiotemporal changes in the supply and demand and the factors underlying these changes, the ecosystem service supply in river basins can be increased to match the demand; this information has great significance for the sustainable development of the basin. By focusing on the cities in China&rsquo;s Huai River Basin, the data on ecosystem service supply and demand from 2010 to 2020 were measured using supply&ndash;demand matrices, and the spatiotemporal characteristics of the supply&ndash;demand balance were analyzed using the supply&ndash;demand index and Moran&rsquo;s I statistics. Next, geographical detectors and multiscale geographically weighted regression models were used to examine the factors influencing the spatiotemporal changes in ecosystem service supply and demand and their spatial effects. The results indicated the following: (1) From 2010 to 2020, ecosystem service supply in the Huai River Basin decreased by 2.51 &times; 108, whereas the ecosystem service demand increased by 4.43 &times; 108; in general, the demand exceeded the supply, and 69.74% cities were in a state of deficit. (2) The Moran&rsquo;s I index of the ecosystem service supply and demand was greater than 0.4, which means that there was a strong spatial clustering, and the characteristics of high&ndash;high clusters gradually weakened and those of low&ndash;low clusters enhanced in the northern and eastern cities. (3) The q values of the ecological-use land area, construction-use land area, rain, and temperature were greater than 0.3, indicating a significant effect on the supply and demand. These findings can provide a targeted reference and basis for the ecological management of the Huai River Basin

Non-Fatal Drowning Risk Prediction Based on Stacking Ensemble Algorithm

Drowning is a major public health problem and a leading cause of death in children living in developing countries. We seek better machine learning (ML) algorithms to provide a novel risk-assessment insight on non-fatal drowning prediction. The data on non-fatal drowning were collected in Qingyuan city, Guangdong Province, China. We developed four ML models to predict the non-fatal drowning risk, including a logistic regression model (LR), random forest model (RF), support vector machine model (SVM), and stacking-based model, on three primary learners (LR, RF, SVM). The area under the curve (AUC), F1 value, accuracy, sensitivity, and specificity were calculated to evaluate the predictive ability of the different learning algorithms. This study included a total of 8390 children. Of those, 12.07% (1013) had experienced non-fatal drowning. We found the following risk factors are closely associated with the risk of non-fatal drowning: the frequency of swimming in open water, distance between the school and the surrounding open waters, swimming skills, personality (introvert) and relationality with family members. Compared to the other three base models, the stacking generalization model achieved a superior performance in the non-fatal drowning dataset (AUC = 0.741, sensitivity = 0.625, F1 value = 0.359, accuracy = 0.739 and specificity = 0.754). This study indicates that applying stacking ensemble algorithms in the non-fatal drowning dataset may outperform other ML models

Natural gas accumulation and models in Ordovician carbonates, Ordos Basin, NW China

According to sedimentary environment, sources, hydrocarbon accumulation characteristics and gas reservoir types of the Ordovician in the Ordos Basin, the Ordovician carbonate rocks in the basin have good gas accumulation conditions. A large number of geological and geochemical evidence shows a triple source supply. In addition to the Upper Carboniferous – Permian coal measures hydrocarbon source rocks as the main hydrocarbon source rocks, the Middle-Upper Ordovician marine hydrocarbon source rocks and Carboniferous Benxi marlstones have certain ability for hydrocarbon. Analysis of the known gas reservoir reveals that the gas in the gas fields of the central basin belongs to thermal cracking gas which is a mixed gas of coal-derived gas and crude oil cracking gas. Coal-derived gas comes from the coal measures hydrocarbon source rocks of the Carboniferous-Permian undoubtedly. Crude oil cracking gas mainly comes from the high temperature cracking gas in the Jurassic reservoir. Asphalts and hydrocarbon inclusions in the Ordovician reservoirs evidence that the oil of the Jurassic paleo-oil reservoir is mainly from the Middle-Upper Ordovician marine hydrocarbon source rocks. Gas accumulation has evolved from oil reservoir to gas reservoir: oil pool formed in the Jurassic and the oil cracked into gas in the Cretaceous. Controlled by tectonic sedimentary setting, four accumulation models of carbonate gas reservoir have been structured. Among them, weathering crust lithostratigraphic gas reservoir in the central part of the basin and composite lithology gas reservoir of structure – bedding karst type in the northwest platform marginal zone are the focus of the carbonate gas exploration. Key words: Ordos Basin, Ordovician, carbonate, hydrocarbon source rock, accumulation characteristics, accumulation evolution, gas reservoir mode

Gas exploration potential of tight carbonate reservoirs: A case study of Ordovician Majiagou Formation in the eastern Yi-Shan slope, Ordos Basin, NW China

On the basis of comprehensive analysis of drilling, gas testing, laboratory analysis and testing data, the characteristics and genesis of tight carbonate reservoirs in Ma51+2 Member of Ordovician Majiagou Formation, eastern Yi-Shan slope, Ordos Basin were examined, and the potential of natural gas exploration and development were analyzed. The tight carbonate reservoir is defined as the reservoir with a porosity of less than 2% and permeability of less than 0.1×10−3 μm2. The Ma51+2 reservoirs are dominantly gypsum mud dolomite, muddy dolomite and Karst-breccia dolomite and has strong heterogeneity, pore types being mainly composed of fracture-dissolution pores and fracture-intercrystalline pores, and thin reservoir layers are distributed in a large area. The unconformity structure adjustment at the top of the Ordovician caused pore creation and pore filling effects, and the joint effect of dissolution pore increase and pore reduction by filling is the major reason for extensive reservoir densification. The thin tight dolomite reservoirs and the overlying adjacent coal source rock in the Upper Paleozoic formed extensive tight carbonate gas with shallow depth (1900−2500 m) and formed a three-dimensional gas containing pattern combined with the Upper Paleozoic tight sandstone gas. The eastern Yi-shan slope in the Ordos Basin has great exploration and development potential. Key words: Ordos Basin, eastern Yi-Shan slope, tight carbonate reservoir, tight gas, exploration potentia

Shear Stress Blunts Tubuloglomerular Feedback Partially Mediated by Primary Cilia and Nitric Oxide at the Macula Densa

The present study tested whether primary cilia on macula densa serve as a flow sensor to enhance nitric oxide synthase 1 (NOS1) activity and inhibit tubuloglomerular feedback (TGF). Isolated perfused macula densa was loaded with calcein red and 4,5-diaminofluorescein diacetate to monitor cell volume and nitric oxide (NO) generation. An increase in tubular flow rate from 0 to 40 nl/min enhanced NO production by 40.0 ± 1.2%. The flow-induced NO generation was blocked by an inhibitor of NOS1 but not by inhibition of the Na/K/2Cl cotransporter or the removal of electrolytes from the perfusate. NO generation increased from 174.8 ± 21 to 276.1 ± 24 units/min in cultured MMDD1 cells when shear stress was increased from 0.5 to 5.0 dynes/cm2. The shear stress-induced NO generation was abolished in MMDD1 cells in which the cilia were disrupted using a siRNA to ift88. Increasing the NaCl concentration of the tubular perfusate from 10 to 80 mM NaCl in the isolated perfused juxtaglomerular preparation reduced the diameter of the afferent arteriole by 3.8 ± 0.1 μm. This response was significantly blunted to 2.5 ± 0.2 μm when dextran was added to the perfusate to increase the viscosity and shear stress. Inhibition of NOS1 blocked the effect of dextran on TGF response. In vitro, the effects of raising perfusate viscosity with dextran on tubular hydraulic pressure were minimized by reducing the outflow resistance to avoid stretching of tubular cells. These results suggest that shear stress stimulates primary cilia on the macula densa to enhance NO generation and inhibit TGF responsiveness. the macula densa is a group of specialized epithelial cells located at the distal segment of the thick ascending limb (TAL) that serves as a sensor of luminal NaCl concentration. Increased NaCl delivery to the macula densa promotes the release of adenosine or ATP, which constricts the afferent arteriole (Af-Art) and decreases single nephron glomerular filtration rate (SNGFR) via a process known as tubuloglomerular feedback (TGF) (2, 37, 57). TGF is a negative feedback mechanism to prevent fluctuations in GFR and flow in the proximal tubule to deliver excess NaCl to the distal nephron and overwhelm its transport capacity. Following acute volume expansion or the ingestion of a sodium load, increases in GFR facilitate the rapid elimination of salt load (29, 40). Baroreflex suppression of renal sympathetic tone and the renin-angiotensin system also contribute to the increase in sodium excretion by inhibiting proximal tubular reabsorption (6, 22). All of these factors result in a large increase in flow to the macula densa, which should trigger a TGF-mediated decrease in GFR that opposes the elimination of the sodium load. However, this decrease in GFR does not occur, partially because of inhibition of TGF responsiveness. Modulation of TGF response following volume expansion should be important in maintaining extracellular sodium and volume balance (42, 52, 53). Indeed, GFR typically increases by 20–30% in humans (4) and in dogs (10) during the postprandial period. Daily salt excretion peaks during the postprandial increase in GFR (21). In these situations, especially following ingestion of a salt load, reduced TGF responsiveness permits high distal NaCl delivery, which could facilitate the excretion of NaCl. The mechanisms for this TGF modulation have not been clarified. Normal luminal flow rate in the distal tubule is about 2–7 nl/min, but it can be temporally reduced to 0 nl/min in salt and volume depletion, and it increases to 25–37 nl/min following acute volume expansion (11, 20, 43). In physiological conditions, increase of tubular flow to the macula densa activates TGF by increasing NaCl delivery (44). However, it also increases shear stress, stretch, and transmural pressure (54, 59); therefore, it possibly activates mechanosensors and other pathways that might modulate TGF responsiveness. The modulation of TGF responsiveness may depend, in part, on increased nitric oxide (NO) production (41, 48, 58), but the source and mechanism for the increase in NO are not known. Primary cilia extend from the surface of many eukaryotic cells (8, 36, 61). While the function of the primary cilia on most cells has remained elusive, they are known to serve as mechanosensors in the mammalian kidney and vascular endothelial cells (8, 36, 61). Primary cilia have been found on the macula densa cells of humans, rats, rabbits, and dogs (17, 33, 47, 50, 56). Little is known about their function (47). The present study examined the hypothesis that primary cilia on macula densa cells serve as a flow sensor to activate NOS1 activity and enhance NO generation, which inhibits TGF responsiveness