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

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

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

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

Anti-thrombotic effect of combination of low molecular heparin and Xueshuantong after replantation of amputated finger

Purpose: To study the effects of low molecular heparin combined with Xueshuantong in preventing thrombosis after replantation of amputated finger.Methods: The treatment group (38 patients) was given 4500 IU of low molecular heparin sodium i.h. (hypodermic injection), q.d.(once daily), with 200 mL of 150 mg Xueshuantong injection and 5 % glucose injection, i.v.d. (intravenous drip), b.i.d. (twice daily). The control group received low molecular heparin sodium at 4500 IU i.h., q.d. alone. Treatment was for 3 days. Thereafter, D-dimer, fibrinogen, hemoglobin, platelets, prothrombin time (PT) and blood coagulation of patients in the 2 groups before and after treatment were compared. Differences in vasospasm, vascular thrombosis, finger necrosis, therapeutic effects and adverse reactions in patients in the 2 groups after treatment were recorded.Results: There were significant improvements in fibrinogen, platelet, PT levels, and blood coagulation time after treatment, with improvements better in the treatment group than in the control group (p < 0.05). Vasospasm cases (3) were lower in the treatment group than in the control group (8, p < 0.05), while vascular thrombosis and finger necrosis in both groups were comparable. Therapeutic effects and recovery were better in the treatment group than in the control group (p < 0.05).Conclusion: Combined injection of Xueshuantong and low molecular heparin exerts antithrombotic effects after replantation of amputated finger, improves coagulation function, and reduces incidence of vasospasm. It has better therapeutic effects than low molecular heparin, and it seems safe.Keywords: Xueshuantong, Low molecular heparin, Replantation, Amputated finger, Thrombosi

Coordination of H2O2 on praseodymia nanorods and its application in sensing cholesterol

The advancement of functional nanomaterials has promoted the development of biomarker sensors underpinning promising analytical tools for a range of bioanalytes such as cholesterol. In this work, we established a light-on fluorescent probe for cholesterol in human serum by coordination of H2O2 on the surface of praseodymia nanorods (Pr6O11 NRs). The distinctive interactions of various nucleotides and H2O2 with praseodymia were examined, whereby good fluorescent quenching and recovery capability were observed. A highly sensitive and selective cholesterol detection was achieved in serum samples with a detection limit of 0.1 mu M and recovery of 97.2-101.3%, respectively, due to the high oxygen mobility of praseodymia. The result suggests strong potential for work towards a key probe for a portable clinical test system for cholesterol as well as other H2O2-deriving biomarkers, potentially addressing the ever-increasing demand for the prevention of cardiovascular disease. (C) 2022 Vietnam National University, Hanoi. Published by Elsevier B.V.This work was supported by the Natural Science Foundation of Shandong Province (Grant ZR2017LB028) , Key R&D Program of Shandong Province (Grant 2018GSF118032) , and Fundamental Research Funds for the Central Universities (Grant 18CX02125A) in China. The project with reference number of ENE2017-82451-C3-2-R from Ministry of Science, Innovation and Universities of Spain is also acknowledged. This work has been co-financed by the 2014-2020 ERDF Operational Programme and by the Department of Economy, Knowledge, Business and University of the Regional Government of Andalusia with reference number of FEDER-UCA18-107316