老年人心源性猝死的生化学机制

老年人心源性猝死的生化学机制白求恩医科大学（１３００２１）于哲夫顾名思义，猝死是突然死亡，事前难以预测，因此了解和掌握猝死前包括生化学改变在内的病情变化是极其困难的，迄今有关猝死生化学机制的报道甚少。目前对此课题研究主要是通过尸体解剖和对复苏成功病例...

Characterization of SiC nanowires prepared on C/C composite without catalyst by CVD

SiC nanowires were prepared on C/C composite surface without catalyst by chemical vapor deposition（CVD） using CH3 SiCl3 as precursor.SEM images of the CVD-product reveal that some long nanowires have grown to tens of micrometers with some gathered as a ball.Some short nanowires agglomerate like chestnut shell with many thorns accompanied by some deposited nano-particles.XRD,Raman-spectrum and FTIR patterns indicate that the product is a typical β-SiC.TEM images show that the nanowires have a wide diameter range from 10 to 100 nm,and some thin nanowires are bonded to the thick one by amorphous CVD-SiC.A SiC branch generates from an amorphous section of a thick one with an angle of 70° between them,which is consistent with the [111] axis stacking angle of the crystal.SAED and fast Fourier transform（FFT） patterns reveal that the nanowires can grow along with different axes,and the bamboo-nodes section is full of stacking faults and twin crystal.The twisted SiC lattice planes reveal that the screw dislocation growth is the main mechanism for the CVD-SiC nanowires.

Biochemical mechanisms of the RNA-induced silencing complex

In less than 10 years since its inception, RNA interference （RNAi） has had extraordinary impact on biomedical science. RNAi has been demonstrated to influence numerous biological and disease pathways. Development and adoption of RNAi technologies have been prolific ranging from basic loss-of-function tools, genome-wide screening libraries to pharmaceutical target validation and therapeutic development. However, understanding of the molecular mechanisms of RNAi is far from complete. The purpose of this brief review is to highlight key achievements in elucidating the bio- chemical mechanisms of the RNA-induced silencing complex and to outline major challenges for the field.

Virological course of hepatitis A virus as determined by real time RT-PCR: Correlation with biochemical, immunological and genotypic profiles

AIM： To undertake analysis of hepatitis A viral load, alanine aminotransferase （ALT）, and viral genotypes with duration of viremia, and to correlate these parameters with CD4^＋/ CD8^＋ lymphocyte populations that control cell-mediated immunity. METHODS： Cell counts were carried out using fresh whole blood collected in EDTA vials using a fluorescence activated cell sorter. Hepatitis A virus （HAV） RNA was extracted from blood serum, reverse transcribed into cDNA and quantified by Real-Time polymerase chain reaction and was genotyped. RESULTS： Among 11 patients, 10 could be analyzed completely. Of these, 3 had severe acute hepatitis （s-AH） and the remainder had a self-limited acute hepatitis A （AHA）, with one patient with fulminant disease （encephalopathy Grade IV） dying on the 4^th d. The ALT level was significantly higher both in AHA （1070.9±894.3; P = 0.0014） and s-AH （1713.9±886.3; P = 0.001） compared to normal controls （23.6±7.2）. The prothrombin time in s-AH patients （21.0 ±2.0; P=0.02） was significantly higher than in AHA （14.3±1.1;P = 0.44）. The CD4^＋/CD8^＋ ratio in AHA patients （1.17 ＋ 0.11; P = 0.22） and s-AH （0.83 ＋ 0.12; P = 0.0002） were lower than seen in normal healthy controls （1.52）. Self-limited cases had peak viral load at the beginning of analysis while in s-AH patients this occurred at the 15TM or 30^th d. In acute and severe groups, one patient each belonged to genotype IA, with the remaining 8 cases belonging to genotype IIIA. The only fulminant hepatic failure case belonged to genotype IA. HAV viral load and AIT values collected during the entire course of the selflimited infection were directly correlated but this was not the case for s-AH patients.CONCLUSION： Based on a small-scale study, the persistently higher viral load of s-AH might be due to diminished cellular immunity and hemolysis. The duration of viremia was dependent on the host, as the viral genotype had no apparent role in clinical outcome of AVH and s-AH cases.

Evidence for the involvement of infectious agents in the pathogenesis of Crohn's disease

Many advances have been made in the understanding of Crohn’s disease (CD) pathogenesis during the last decade. CD is currently seen as a predominantly T-lym-phocyte-driven disease characterized by the presence of a complex cocktail of interacting cytokines, chemokines and other mediators produced by a variety of cell types. Prevailing theories of CD pathogenesis suggest that patients’ T-lymphocytes are inappropriately activated in the setting of an immune imbalance, which is itself caused by an unfortunate confluence of genetic and en- vironmental factors. The T-cell response then leads to the chronic inflammation characteristic for the disease. Various environmental factors may play a role in the development of CD, but microbes are most consistently implied. This theory is based on epidemiological, clinico- pathological, genetic and experimental evidence. Despite the abundance of arguments for the implication of bac-teria in the aetiopathogenesis of CD, the precise role of bacteria in this disease still remains elusive. Three not necessarily mutually exclusive theories have been pro- posed: (1) an unidentified persistent pathogen; (2) an abnormally permeable mucosal barrier leading to exces-sive bacterial translocation; and (3) a breakdown in the balance between putative "protective" versus "harmful" intestinal bacteria ("dysbiosis"). At present, one cannot exclude with certainty any of these three proposed hy-potheses; they may all apply to CD to a certain extent.

New insights into the activation mechanism of store-operated calcium channels:roles of STIM and Orai

The activation of Ca2+ entry through store-operated channels by agonists that deplete Ca2+ from the endoplasmic reticulum (ER) is a ubiquitous signaling mechanism, the molecular basis of which has remained elusive for the past two decades. Store-operated Ca2+-release-activated Ca2+ (CRAC) channels constitute the sole pathway for Ca2+ entry following antigen-receptor engagement. In a set of breakthrough studies over the past two years, stromal interaction molecule 1 (STIM1, the ER Ca2+ sensor) and Orai1 (a pore-forming subunit of the CRAC channel) have been identified. Here we review these recent studies and the insights they provide into the mechanism of store-operated Ca2+ channels (SOCCs).

Growth Mechanism and Characterization of Single-crystalline Ga-doped SnO2 Nanowires and Self-organized SnO2/Ga2O3 Heterogeneous Microcomb Structures

Single-crystalline Ga-doped SnO2 nanowires and SnO2：Ga2O3 heterogeneous microcombs were synthesized by a simple one-step thermal evaporation and condensation method. They were characterized by means of X-ray powder diffraction （XRD）, field-emission scanning electron microscopy （FE-SEM）, energy-dispersive X-ray spectroscopy （EDS）, transmission electron microscopy （TEM） and selected-area electron diffraction （SAED）. FE-SEM images showed that the products consisted of nanowires and mierocombs that represent a novel morphology. XRD, SAED and EDS indicated that they were single-crystalline tetragonal SnO2. The influence of experimental conditions on the morphologies of the products is discussed. The morphology of the product showed a ribbon-like stem and nanoribbon array aligned evenly along one or both side of the nanoribbon. It was found that many Ga2O3 nanoparticles deposited on the surface of the microcombs. The major core nanoribbon grew mainly along the [110] direction and the self-organized branching nanoribbons grew epitaxially along [110] or [110] orientation from the （110） plane of the stem. A growth process was proposed for interpreting the growth of these remarkable SnO2：Ga2O3 heterogeneous microcombs. Due to the heavy doping of Ga, the emission peak in photoluminescence spectra has red-shifted as well as broadened significantly.

Correlation of serum leptin levels with anthropometric and metabolic parameters and biochemical liver function in Chinese patients with chronic hepatitis C virus infection

AIM: To determine serum leptin levels and investigate their correlations with anthropometric and metabolic parameters and biochemical liver function in patients with chronic hepatitis C virus (HCV) infection and their potential clinical implications.METHODS: Forty-two chronic HCV-infected patients without anti-viral treatment were enrolled in this study, 30 patients had chronic hepatitis C, 10 had cirrhosis, and 2 had hepatocellular carcinoma (HCC). Thirty age- and sex-matched healthy individuals served as controls. Serum leptin levels were determined by ELISA. The biochemical liver function and serum lipids were determined at the same time. The height and body weight of patients and controls were measured, and body mass index (BMI) and body fat were calculated simultaneously. The correlations of serum leptin levels with anthropometric and metabolic parameters and biochemical liver function were assessed statistically.RESULTS: The mean of serum leptin levels in patients with chronic hepatitis C, HCV-associated cirrhosis, HCVassociated HCC and control groups was (6.13±3.94),(5.25±4.21), (4.17±0.28), and (3.59±3.44) ng/mL, respectively. The serum leptin level in patients with chronic hepatitis C was significantly higher than that in controls. The serum leptin levels between cirrhotic patients and controls and between male and female cirrhotic patients had no significant difference. Serum leptin levels were positively-correlated with body fat, BMI, and apolipoprotein B (Apo B) in patients with chronic HCV infection. The serum alanine aminotransferase (ALT) levels were closelycorrelated with BMI in patients with chronic hepatitis C. CONCLUSION: HCV infection interferes with fat and lipid metabolism in patients with chronic HCV infection and leptin may play a role in hepatosteatosis.

Biochemical Mechanism of the Eutrophication and Its Prevention — the Deep Treatment of Waste Water and Its Denitrification and Dephosphorization

Biochemical mechanism of forming the red tide is discussed in this paper. The existence of a large number of nitrates and phosphates in the eutrophic water is the prerequisite of explosive increase of algae and the forming of red tide. Reduction of eutrophication is an important approach to preventing the red tide. The method of deep treatment of the waste water and its denitrification and dephosphorization are introduced, and a new opinion on the red tide formation and fundamental prevention is put forward.

Osteoporosis as A Source of Tissue Mineralization Research on Osteoporosis Therapy and Dissolution of Arterial Mineralization

Based on research conducted by the author in the last thirty-five years, this article presents the physicochemical mechanisms of the osteoporosis process, transport of substances created as its result, and the phenomena of tissue mineralization resulting from osteoporosis. Examination of bones, joint cartilage, arteries, veins, parts of heart, thyroid, salivary glands, various tumors and others was conducted with the use of biological and polarizing microscopy, SEM, EDS, ASA, IR, Raman spectroscopy, and X-ray diffraction. Several devices of the same kind, e.g. different types of SEM, were used. Specimens used for examination were obtained from post-surgery and post rnortem materials. Examination of human bones focused on their mineralization and demineralization （osteoporosis）. Examination of the mineralization of other tissues was conducted in terms of the ageing of human body. Obtained results show that the process of osteoporosis leads not just to mechanical degradation of bones, but through the transport of ions （mainly Ca and P）, it also causes mineralization of soft tissue. Such mineralization occurs in mineralization centers that have been classified in regard to genetics. Tissue mineralization in its first stage is latent and consists of including atoms, mainly Ca and P, into the biological structures of compounds that build the tissues. Latent mineralization may evolve into the next stage--apparent mineralization. Both types of mineralization cause many health issues and may lead to death. This article also presents initial results of research on dissolution of aortic mineralization.

Basic formation mechanisms of Lake Doroninskoye soda water, East Siberia, Russia

The primary scientific goal of studying salt lakes is to better understand the formation of small continental- type hydrogeochemical systems. Many scientists have attributed the metamorphism of the chemical composition of salt lakes to the evaporative concentration of water. How- ever, the formation of soda water is inconsistent with this hypothesis. Thus, analyzing intrabasinal biochemical pro- cesses and water--rocks interactions during the evaporative concentration of water allows us to understand the major mechanisms of the formation and evolution of water com- positions. Therefore, the aim of this paper is to identify the key processes involved in the formation of the chemical composition of the water in Lake Doroninskoye. An analysis of the distribution of major components shows that Na＋, HCO3-, CO32-, and C1- are dominant in this water. High concentrations of these elements are the result of evaporative water concentration. Calcium, magnesium, and potassium are not accumulated because the water is saturated in min- erals containing these elements. The main barrier to the growth of the sulfate content of water is sulfate reduction. This process also contributes to the additional reproduction of carbon dioxide, which reacts with the products of the hydrolysis of aluminosilicates OH- to form HCO3- and CO32-, thus further contributing to the natural processes of soda formation.

Interactions between invasive plants and heavy metal stresses:a review

Global changes have altered the distribution pattern of the plant communities,including invasive species.Anthropogenic contamination may reduce native plant resistance to the invasive species.Thus,the focus of the current review is on the contaminant biogeochemical behavior among native plants,invasive species and the soil within the plant-soil ecosystem to improve our understanding of the interactions between invasive plants and environmental stressors.Our studies together with synthesis of the literature showed that(i)the impacts of invasive species on environmental stress were heterogeneous,(ii)the size of the impact was variable and(iii)the influence types were multidirectional even within the same impact type.However,invasive plants showed self-protective mechanisms when exposed to heavy metals(HMs)and provided either positive or negative influence on the bioavailability and toxicity of HMs.On the other hand,HMs may favor plant invasion due to the widespread higher tolerance of invasive plants to HMs together with the‘escape behavior’of native plants when exposed to toxic HM pollution.However,there has been no consensus on whether elemental compositions of invasive plants are different from the natives in the polluted regions.A quantitative research comparing plant,litter and soil contaminant contents between native plants and the invaders in a global context is an indispensable research focus in the future.

Simulation of organic nitrates in Pearl River Delta in 2006 and the chemical impact on ozone production

Organic nitrates are secondary atmospheric pollutants that play a key role in ozone and aerosol production. This study focused on the simulation of organic nitrates through a box model coupled with RACM2 （Regional Atmospheric Chemistry Mechanism, version 2）, based on data from the PRIDE-PRD2006 campaign in Backgarden, China. Our study found that an overestimation of organic nitrate production rate was generated by the model. Furthermore, the effective production ratio （a^ff） of organic nitrates was around 0.033 after optimizing its chemical production module. The chemical impacts of organic nitrates on ozone production were related to VOC-OH reactivity and aeff. We found that VOC-OH reactivity was positively related to aeff, resulting in the suppression of ozone production caused by organic nitrates, which showed that P（Ox=O3＋NO2） increased initially and subsequently decreased with VOC-OH reactivity. These results highlight the importance of organic nitrate＇s impact on ozone production in strategies to control ozone pollution, specifically regarding the reduction of low-molecular-weight VOCs in the Pearl River Delta.

Summer circulation structure and formation mechanism in the Beibu Gulf

Due to limited in situ data and diagnostic numerical models, the summer circulation structure and formation mechanism in the Beibu Gulf have always been in controversy in the past 50 years. Therefore, a new three-dimensional hindcast model was built within the northwestern South China Sea(SCS), forced with the daily averaged wind, heat flux, lateral flux, as well as tidal harmonic and eight major rivers discharges. And the east boundary was set up far away off the Qiongzhou Strait(QS). Lastly, the model results were consistent with not only the synchronous observation data from the project 908 but also the historical observed data. As a result, the summer circulation structure was revealed that the southern Gulf was occupied by an anticyclonic eddy whereas the northern Gulf was dominated by a cyclonic gyre. Although the circulation major structure was stable, its area and strength had yearly and monthly oscillation. The other three sensitive experiments indicated that the circulations in the southern and northern Gulf were driven by the SCS circulation and monsoon wind, respectively. After the theoretical analysis of the potential vorticity budget, it was further revealed the circulation in the northern Gulf was driven by the positive wind stress curl in summer. Besides, the river discharge was also significant as the vertical circulation had two layer structures outside the mouth of the Red River. Generally, this work calls for the further research on other subjects, such as ocean biogeochemical or marine fisheries.

Growth of skyrmionic MnSi nanowires on Si： Critical importance of the SiO2 layer

MnSi in the B20 structure is a prototypical helimagnet that forms a skyrmion lattice, a vortex-like spin texture under applied magnetic field. We have systematically explored the synthesis of single crystal MnSi nanowires via controlled oxide-assisted chemical vapor deposition and observed a characteristic signature of skyrmion magnetic ordering in the MnSi nanowires. The thickness of the SiO2 layer on the Si substrate plays the key role in obtaining a high yield of B20 MnSi skyrmion nanowires. A growth mechanism was proposed that is consistent with the existence of an optimum SiO2 thickness. A growth phase diagram was constructed based on the extensive studies of various growth conditions for various MnSi nanostructures. The persistence of both the helicoidal and skyrmion magnetic ordering in the one-dimensional wires was directly revealed by ac and dc magnetic measurements.