Multiple pathogenic factor-induced complications of cirrhosis in rats: A new model of hepatopulmonary syndrome with intestinal endotoxemia

AIM： To develop and characterize a practical model of Hepatopulmonary syndrome. （HPS） in rats.METHODS： The experimental animals were randomized into five feeding groups： （1） control （fed standard diet）, （2） control plus intraperitoneal injection with lipopolysaccharide （LPS）, （3） cirrhosis （fed a diet of maize flour, lard, cholesterol, and alcohol plus subcutaneously injection with carbon tetrachloride （CCI4） oil solution）, （4） cirrhosis plus LPS, and （5） cirrhosis plus glycine and LPS. The blood, liver and lung tissues of rats were sampled for analysis and characterization. Technetium 99m-labeled macroaggregated albumin （Tc99m-MAA） was used to test the dilatation of pulmonary microvasculature.RESULTS： Typical cirrhosis and subsequent hepato- pulmonary syndrome was observed in the cirrhosis groups after an 8 wk feeding period. In rats with cirrhosis, there were a decreased PaO2 and PaCO2 in arterial blood, markedly decreased arterial 02 content, a significantly increased alveolar to arterial oxygen gradient, an increased number of bacterial translocated within mesenteric lymph node, a significant higher level of LPS and tumor necrosis factor-α （TNF-α） in plasma, and a significant greater ratio of Tc99m-MAA brain-overlung radioactivity. After LPS administration in rats with cirrhosis, various pathological parameters got worse and pulmonary edema formed. The predisposition of glycine antagonized the effects of LPS and significantly alleviated various pathological alterations.

Circulating lncRNA MHRT predicts survival of patients with chronic heart failure

Background It has been reported that lncRNA myosin heavy-chain-associated RNA transcripts(MHRT)can inhibit the apoptosis of cardiomyocytes.It is one of the major pathological changes leading to chronic heart failure.Methods The expression level of lncRNA MHRT was assessed by qRT-PCR.Diagnostic values of lncRNA MHRT for chronic heart failure were analyzed by ROC curve analysis.Cell apoptosis was detected by cell apoptosis assay.Results The results demonstrated that expression of lncRNA MHRT in plasma was down-regulated in patients with chronic heart failure compared to that in healthy people.Down-regulation of lncRNA MHRT distinguished chronic heart failure from healthy people.Over-expression of lncRNA MHRT inhibited the apoptosis of human cardiomyocyte cell line AC16 after H2O2 treatment.Follow-up study showed that chronic heart failure patients with lower expression levels of lncRNA MHRT had worse survival conditions compared to patients with higher expression levels of lncRNA MHRT.Conclusion We concluded that circulating lncRNA MHRT might serve as a diagnostic and prognostic marker for chronic heart failure treatment.

A buffer overflow detection and defense method based on RiSC-V instruction set extension

Buffer overflow poses a serious threat to the memory security of modern operating systems.It overwrites the con-tents of other memory areas by breaking through the buffer capacity limit,destroys the system execution environ-ment,and provides implementation space for various system attacks such as program control flow hijacking.That makes it a wide range of harms.A variety of security technologies have been proposed to deal with system security problems including buffer overflow.For example,No eXecute(NX for short)is a memory management technology commonly used in Harvard architecture.It can refuse the execution of code which residing in a specific memory,and can effectively suppress the abnormal impact of buffer overflow on control flow.Therefore,in recent years,it has also been used in the field of system security,deriving a series of solutions based on NX technology,such as ExecShield,DEP,StackGuard,etc.However,these security solutions often rely too much on the processor archi-tecture so that the protection coverage is insufficient and the accuracy is limited.Especially in the emerging system architecture field represented by RiSC-V,there is still a lack of effective solutions for buffer overflow vulnerabilities.With the continuous rapid development of the system architecture,it is urgent to develop defense methods that are applicable to different system application environments and oriented to all executable memory spaces to meet the needs of system security development.Therefore,we propose BOP,A new system memory security design method based on RISC-V extended instructions,to build a RISC-V buffer overflow detection and defense system and deal with the buffer overflow threat in RIsC-V.According to this method,NX technology can be combined with program control flow analysis,and Nx bit mechanism can be used to manage the executability of memory space,so as to achieve a more granular detection and defense of buffer overflow attacks that may occur in RISC-V system environment.In addition,The memory management and control function of BOP is not only very suitable for solving the security problems in the existing single architecture system,but also widely applicable to the combina-tion of multiple heterogeneous systems.

MemSC： A Scan-Resistant and Compact Cache Replacement Framework for Memory-Based Key-Value Cache Systems

Memory-based key-value cache systems, such as Memcached and Redis, have become indispensable components of data center infrastructures and have been used to cache performance-critical data to avoid expensive back-end database accesses. As the memory is usually not large enough to hold all the items, cache replacement must be performed to evict some cached items to make room for the newly coming items when there is no free space. Many real-world workloads target small items and have frequent bursts of scans （a scan is a sequence of one-time access requests）. The commonly used LRU policy does not work well under such workloads since LRU needs a large amount of metadata and tends to discard hot items with scans. Small decreases in hit ratio can result in large end-to-end losses in these systems. This paper presents MemSC, which is a scan-resistant and compact cache replacement framework for Memcached. MemSC assigns a multi-granularity reference flag for each item, which requires only a few bits （two bits are enough for general use） per item to support scanresistant cache replacement policies. To evaluate MemSC, we implement three representative cache replacement policies （MemSC-HM, MemSC-LH, and MemSC-LF） on MemSC and test them using various workloads. The experimental results show that MemSC outperforms prior techniques. Compared with the optimized LRU policy in Memcached, MemSC-LH reduces the cache miss ratio and the memory usage of the resulting system by up to 23% and 14% respectively.