Thoracoscopic Left Atrial Appendage Excision Plus Ablation for Atrial Fibrillation to Prevent Stroke

Atrial fibrillation (AF) patients with a previous stroke are often at a high risk of recurrent stroke and bleeding. Anticoagulation therapy in such patients is a challenging dilemma. Thoracoscopic left atrial appendage excision (LAAE) plus AF ablation is an interventional approach offered to some AF patients. We hypothesized that this approach may be suitable as a secondary stroke prevention strategy for these high-risk patients. Between January 2013 and December 2016, a total of 44 patients (26 male; mean age 65.0 ± 9.1 years) with nonvalvular AF and a previous stroke or systemic thromboembolic event were enrolled. The patients underwent thoracoscopic LAAE plus AF ablation by experienced operators and were followed up for 2 years (at 1, 3, 6, 9, and 12 months postoperatively and every 6 months thereafter). Thromboembolic and major bleeding events were recorded. Cerebral computed tomography or magnetic resonance imaging and 7-day Holter monitoring were performed annually. Mean CHA2DS2-VASc and HAS-BLED scores were 4.2 ± 1.2 and 3.3 ± 0.7, respectively. All patients discontinued oral anticoagulation therapy after the surgical intervention. One patient suffered a periprocedural transient ischemic attack, and another was diagnosed with a new ischemic stroke at 491 days after surgery. The annual rate of total thromboembolism was 2.05%. No deaths or major bleeding events were observed postoperatively. The rate of successful AF ablation with no AF recurrence was 76.3%. Transthoracoscopic LAAE plus AF ablation may be a promising approach for this high-risk population. Thromboembolism event in this secondary prevention cohort was low, even without oral anticoagulation treatment

Solute Carrier Family 1 (SLC1A1) Contributes to Susceptibility and Psychopathology Symptoms of Schizophrenia in the Han Chinese Population

Objective: Schizophrenia (SZ) is a common and complex psychiatric disorder that has a significant genetic component. The glutamate hypothesis describes one possible pathogenesis of SZ. The solute carrier family 1 gene (SLC1A1) is one of several genes thought to play a critical role in regulating the glutamatergic system and is strongly implicated in the pathophysiology of SZ. In this study, we identify polymorphisms of the SLC1A1 gene that may confer susceptibility to SZ in the Han Chinese population. Methods: We genotyped 36 single-nucleotide polymorphisms (SNPs) using Illumina GoldenGate assays on a BeadStation 500G Genotyping System in 528 paranoid SZ patients and 528 healthy controls. Psychopathology was rated by the Positive and Negative Symptom Scale. Results: Significant associations were found in genotype and allele frequencies for SNPs rs10815017 (p = 0.002, 0.030, respectively) and rs2026828 (p = 0.020, 0.005, respectively) between SZ and healthy controls. There were significant associations in genotype frequency at rs6476875 (p = 0.020) and rs7024664 (p = 0.021) and allele frequency at rs3780412 (p = 0.026) and rs10974573 (p = 0.047) between SZ and healthy controls. Meanwhile, significant differences were found in genotype frequency at rs10815017 (p = 0.015), rs2026828 (p = 0.011), and rs3780411 (p = 0.040) in males, and rs7021569 in females (p = 0.020) between cases and controls when subdivided by gender. Also, significant differences were found in allele frequency at rs2026828 (p = 0.003), and rs7021569 (p = 0.045) in males, and rs10974619 in females (p = 0.044). However, those associations disappeared after Bonferroni\u27s correction (p\u27s \u3e 0.05). Significant associations were found in the frequencies of four haplotypes (AA, CA, AGA, and GG) between SZ and healthy controls (chi (2) = 3.974, 7.433, 4.699, 4.526, p = 0.046, 0.006, 0.030, 0.033, respectively). There were significant associations between rs7032326 genotypes and PANSS total, positive symptoms, negative symptoms, and general psychopathology in SZ (p = 0.002, 0.011, 0.028, 0.008, respectively). Conclusion: The present study provides further evidence that SLC1A1 may be not a susceptibility gene for SZ. However, the genetic variations of SLC1A1 may affect psychopathology symptoms

Software Based Memory Forwarding Computer Architecture Course Project Final Report Software Support Memory Forwarding

Memory forwarding is an effective way to dynamically optimize the data layout. It provides a safe way to improve the performance of cache by actively creating better data locality. The existing memory forwarding mechanism needs additional hardware support to perform the address redirection, which greatly limits its real application. To put the memory forwarding technique into widely practice, we propose a new way of software-based implementation. Based on the fact that good data layout can bring much improvement of cache performance and actual forwarding is a rare event during the execution, our experiment shows that reasonable speedup that can be achieved by using this software-based memory forwarding technique

DBmbench: Fast and Accurate Database Workload Representation on Modern Microarchitecture

With the proliferation of database workloads on servers, much recent research on server architecture has focused on database system benchmarks. The TPC benchmarks for the two most common server workloads, OLTP and DSS, have been used extensively in the database community to evaluate the database system functionality and performance. Unfortunately, these benchmarks fall short of being effective in microarchitecture and memory system research due to several key shortcomings. First, setting up the experimental environment and tuning these benchmarks to match the workload behavior of interest involves extremely complex procedures. Second, the benchmarks themselves are complex and preclude accurate correlation of microarchitecture- and memory-level bottlenecks to dominant workload characteristics. Finally, industrial-grade configurations of such benchmarks are too large and preclude their use in detailed but slow microarchitectural simulation studies of future servers. In this paper, we first present an analysis of the dominant behavior in DSS and OLTP workloads, and highlight their key processor and memory performance characteristics. We then introduce a systematic scaling framework to scale down the TPC benchmarks. Finally, we propose the DBmbench, consisting of two substantially scaled-down benchmarks: µTPC-H and µTPC-C that accurately (> 95%) capture the processor and memory performance behavior of DSS and OLTP workloads. Copyright c ○ 2005 Minglong Shao. Permission to copy is hereby granted provided the original copyright notice is reproduced in copies made.

A Novel Stick-Slip Type Rotary Piezoelectric Actuator

A novel stick-slip rotary piezoelectric actuator is designed for optical use. The actuator is proposed, fabricated, and tested with the aim of realizing both fine resolution and a long stroke. The dynamic model of the actuator is established, and simulations are performed to discover how the input driving voltage affects the stick-slip motion of the actuator. An experimental system is built to evaluate the performance of the actuator at different frequencies, voltages, and numbers of driving piezoelectric stacks. Experimental results show that the minimal output stepping angle is 3.5 μrad (0.2 millidegrees) under a sawtooth waveform having a voltage of 13 V and frequency of 3000 Hz and that the velocity reaches 0.44 rad/s (25°/s) under a sawtooth waveform having a voltage of 93 V and frequency of 3000 Hz, while the stroke is infinite. The proposed actuator provides stable and accurate rotary motion and realizes a high velocity