Reduced expression of cardiac ryanodine receptor protects against stress-induced ventricular tachyarrhythmia, but increases the susceptibility to cardiac alternans

Peer ReviewedPostprint (author's final draft

Homogeneity in terrestrial land cover is reflected in fish diversity patterns in a Chinese river system

In river systems worldwide, land cover changes have been identified as major drivers of biodiversity change. Quantifying how terrestrial land cover impacts riverine diversity requires local biodiversity assessments. In this study, we investigated the association of terrestrial land cover and the corresponding riverine fish species communities using eDNA‐metabarcoding in the Chinese Shaying River basin. This basin is home to about 37 million people and is largely dominated by a mix of intense agriculture and urban areas, creating a relatively homogeneous, intensely used landscape. We investigated whether the homogeneous landscape is mirrored in the composition and structure of fish communities in the river network. We sampled eDNA in spring and fall of 2018, amplified it with a primer designed for local fish species and used operational taxonomic units (OTU) assigned to fish as proxy for diversity. Furthermore, we used redundancy analysis, general linear models, and distance decay curves to assess the effects of land cover on fish communities. We found that the Shaying River showed relatively high basin‐wide richness (63 OTU) and seasonal differences in local richness, but limited community differentiation. Variations in alpha‐ and beta‐diversity, measured as local OTU richness and pairwise distance‐decay across the basin were low. Redundancy analysis showed only a weak association between observed aquatic communities and their terrestrial surroundings in a 10 km buffer upstream. The lack of community differentiation assessed by eDNA metabarcoding reflects the homogeneous and intense land‐use in this basin

Multiband slot antennas for metal back cover mobile handsets

New multiband integrated slot antennas for mobile handsets are presented for GSM, DCS, PCS and WCDMA, GPS and WIFI 2.4 GHz. Prototypes, both simulated and measured, are realised in the metal back cover away from the hand. Perturbations due to tissue proximity are simulated using a CTIA compliant hand phantom

The cardiac ryanodine receptor, but not sarcoplasmic reticulum Ca2-ATPase, is a major determinant of Ca2 alternans in intact mouse hearts

Sarcoplasmic reticulum (SR) Ca2+ cycling is governed by the cardiac ryanodine receptor (RyR2) and SR Ca2+-ATPase (SERCA2a). Abnormal SR Ca2+ cycling is thought to be the primary cause of Ca2+ alternans that can elicit ventricular arrhythmias and sudden cardiac arrest. Although alterations in either RyR2 or SERCA2a function are expected to affect SR Ca2+ cycling, whether and to what extent altered RyR2 or SERCA2a function affects Ca2+ alternans is unclear. Here we employed a gain-of-function RyR2 variant (R4496C) and the phospholamban-knockout (PLB-KO) mouse model to assess the effect of genetically enhanced RyR2 or SERCA2a function on Ca2+ alternans. Confocal Ca2+ imaging revealed that RyR2-R4496C shortened SR Ca2+ release refractoriness and markedly suppressed rapid pacing-induced Ca2+ alternans. Interestingly, despite enhancing RyR2 function, intact RyR2-R4496C hearts exhibited no detectable spontaneous SR Ca2+ release events during pacing. Unlike for RyR2, enhancing SERCA2a function by ablating PLB exerted a relatively minor effect on Ca2+ alternans in intact hearts expressing RyR2 wildtype or a loss-of-function RyR2 variant, E4872Q, that promotes Ca2+ alternans. Furthermore, partial SERCA2a inhibition with 3 µM 2,5-di-tert-butylhydroquinone (tBHQ) also had little impact on Ca2+ alternans, while strong SERCA2a inhibition with 10 µM tBHQ markedly reduced the amplitude of Ca2+ transients and suppressed Ca2+ alternans in intact hearts. Our results demonstrate that enhanced RyR2 function suppresses Ca2+ alternans in the absence of spontaneous Ca2+ release and that RyR2, but not SERCA2a, is a key determinant of Ca2+ alternans in intact working hearts, making RyR2 an important therapeutic target for cardiac alternans.Peer ReviewedPostprint (published version

3D orientation super-resolution spatial-frequency-shift microscopy

Super-resolution mapping of the 3D orientation of fluorophores reveals the alignment of biological structures where the fluorophores are tightly attached, and thus plays a vital role in studying the organization and dynamics of bio-complexes. However, current super-resolution imaging techniques are either limited to 2D orientation mapping or suffer from slow speed and the requirement of special labels in 3D orientation mapping. Here, we propose a novel polarized virtual spatial-frequency-shift effect to overcome these restrictions to achieve a universal 3D orientation super-resolution mapping capability. To demonstrate the mechanism, we simulate the imaging process and reconstruct the spatial-angular information for sparsely distributed dipoles with random 3D orientations and microfilament-like structures decorated with fluorophores oriented parallel to them. The 3D orientation distribution can be recovered with a doubled spatial resolution and an average angular precision of up to 2.39 degrees. The performance of the approach with noise has also been analyzed considering real implementation.Comment: 22 pages, 5 figure

A Real-Time Augmented Reality System for Industrial Tele-Training

Abstract Augmented Reality (AR) is a departure from standard virtual reality in a sense that it allows users to see computer generated virtual objects superimposed over the real world through the use of see-through head-mounted display. Users of such system can interact in the real/virtual world using additional information, such as 3D virtual models and instructions on how to perform these tasks in the form of video clips, annotations, speech instructions, and images. In this paper, we describe two prototypes of a collaborative industrial Tele-training system. The distributed aspect of this system will enables users on remote sites to collaborate on training tasks by sharing the view of the local user equipped with a wearable computer. The users can interactively manipulate virtual objects that substitute real objects allowing the trainee to try out and discuss the various tasks that needs to be performed. A new technique for identifying real world objects and estimating their coordinates in 3D space is introduced. The method is based on a computer vision technique capable of identifying and locating Binary Square Markers identifying each information stations. Experimental results are presented

Clinical and genetic characteristics of Charcot-Marie-Tooth disease with cerebellar ataxia

Charcot-Marie-Tooth disease (CMT) is a group of hereditary motor and sensory neuropathy predominantly with peripheral neuropathy. It is characterized by progressive symmetric distal-predominant weakness, amyotrophy, sensory loss and reduced or absent deep tendon reflexes. CMT is usually divided into CMT1 type with demyelination and CMT2 type with axonal lesions according to electrophysiological and pathological characteristics. In addition to peripheral nervous system lesions, some CMT subtypes may also involve the central nervous system or other organs. The CMT patients with cerebellar system involvement also have cerebellar ataxia which can be seen as CMT1F type and CMT2E type caused by mutations in neurofilament light chain (NEFL) gene, CMT2Z with mutations in MORC family CW-type zinc finger 2 (MORC2) gene, CMT-6B with mutations in solute carrier family 25 member 46 (SLC25A46) gene, CMT2B2 with mutations in polynucleotide kinase 3′-phosphatase (PNKP) gene and so on. In recent years, CMT overlapping phenotypes have become a hot topic of research, among which CMT with cerebellar ataxia is a clinically and genetically heterogeneous group of disorders, and is prone to misdiagnosis clinically. This article reviews the clinical and genetic characteristics of CMT with cerebellar ataxia, aiming to provide reference for the earlier recognition and therapeutic strategies