薄膜双栅MOSFET体反型现象的研究

通过对QM模型的介绍,说明了薄膜双栅MOSFET体反型现象是量子效应的结果,并对QM模型中提出的反型层质心概念进行了剖析,阐述了其重要的物理意义和应用价值。利用反型层质心概念,提出了一组形式非常简单,且与体硅单沟道MOSFET表达式十分相似的薄膜双栅MOSFET亚阈值区反型层载流子浓度和亚阈值电流的表达式,与MEDICI模拟结果的比较证明了其精确性。应用反型层质心及所提出的亚阈值区模型,对薄膜双栅MOSFET体反型现象进行了深入的分析,提出了一个能够较好体现体反型作用的硅膜厚度范围。

浅谈打入型反滤体在预制桩生态护岸工程上的研究

装配式生态护岸是保障国家水利行业实现碳减排目标的重要手段和措施,为实现国家碳达峰、碳中和任务提供有效技术支撑。本文对近年来有关预制桩墙在连接方面的现状实施情况及存在问题进行剖析,探讨打入型反滤体在预制桩生态护岸工程上的研究,并针对初步应用的情况进行深入研究分析,以推动该成果在类似工程中的应用。

Modeling and analysis of azimuthal AVO responses from a viscoelastic anisotropic reflector

We propose a method for mOdeling azimuthal AVO responses from a fractured i reflector. The method calculates the integrated reflected wavetrains, and the wavetrains contain elastodynamic information including the contrast in impedance and anelasticity i across interfaces, the intemal anisotropic propagation, the dispersion and attenuation along i the wave path, and tuning and interference. The results suggest that for large angles of incidence, the velocity dispersion and attenuation increase the amplitudes of PP waves from the top and decrease those from the bottom. For azimuthal responses at specific angles of incidence, the reflected wavetrains of PP waves tend to have longer duration with increasing azimuth. In contrast, model-converted PSV and PSH reflections show stable azimuthal features and are less affected by the reflector thickness. The amplitudes of PSV reflections increase with increasing azimuth; moreover, the waves have no reflection energy at 0° and 90° azimuth and maximum amplitude at 45° azimuth.

Trust model based on individual experience

To improve the accuracy of node trust evaluation in a distributed network, a trust model based on the experience of individuals is proposed, which establishes a new trust assessment system by introducing the experience factor and the comparative experience factor. The new evaluation system considers the differences between individuals and interactive histories between nodes, which solves the problem that nodes have inaccurate assessments due to the asymmetry of nodes to a certain extent. The algorithm analysis indicates that the new model uses different deviating values of tolerance evaluation for different individuals and uses different updating values embodying node individuation when updating feedback credibility of individuals, which evaluates the trust value more reasonably and more accurately. In addition, the proposed algorithm can be used in various trust models and has a good scalability.

Construction of Double Cross-over Expression Vector for Chloroplast Multicistron in Brassica napus L.

[Objective] This study aimed to construct Brassica napus chloroplast multi- cistron double cross-over expression vector, to lay the foundation for the genetic engi- neering research of Brassica napus chloroplast. [Method] Two primers were designed based on the known Brassica napus chloroplast DNA sequences AF267640 and Z50868 in GenBank. By using PCR method, two Brassica napus L. chloroplast DNA fragments were obtained, which were named RbcL and ACCD. The two Brassica na- pus chloroplast DNA homologous fragments were then cloned into plasmid pMD18-T to obtain recombinant plasmid pHBM715. Tandem expression cassette harboring spectinomycin-resistant gene aadA, mannanase gene man and green fluorescent pro- tein gene gfp was cloned into the plasmid pHBM715, thereby constructing Brassica napus chloroplast multicistron double cross-over expression vector pHBM716, which was transformed into Escherichia coil for expression and identification. [Result] Plate qualitative analysis was conducted for the functional identification of expression cas- sette in the constructed Brassica napus chloroplast multicistron double cross-over ex- pression vector, results showed that the three genes of the same multicistron were all expressed in E. coil [Conclusion] This study successfully constructed Brassica napus chloroplast multicistron double cross-over expression vector, which laid the foundation for the genetic engineering of Brassica napus chloroplast.

Detection of YMDD.mutants using universal template real-time PCR

AIM： To establish a rapid and accurate method for the detection of lamivudine-resistant mutations in hepatitis B virus and monitor of lamivudine resistance during lamivudine treatment in patients with chronic hepatitis B virus infection. METHODS： We established a real-time PCR method using a universal template and TaqMan probe to detect YMDD mutants. Variants of YVDD and YIDD were tested by individual reactions （reaction Ⅴ and reaction Ⅰ） and total hepatitis B viruses were detected in another reaction for control （reaction C）. Results were determined by △Ct〈3.5 （△Ct = Ct of reaction Ⅴ or Ⅰ - Ct of reaction C）. Clones of the HBV polymerase gene containing different YMDD mutations were tested. Serum samples from 163 lamivudine-treated patients with chronic hepatitis B virus infection were detected using this method and the results were confirmed by DNA sequencing. RESULTS： As many as 1000 copies per milliliter of widetype plasmid were detected and nonspecific priming was excluded. In the 163 samples from patients treated with lamivudine, lamivudine-resistant mutations were detected in 51 samples. CONCLUSION： This universal real-time PCR is a rapid and accurate method for quantification of YMDD mutants of HBV virus in lamivudine-treated patients and can be used to monitor lamivudine-resistant mutations before and during lamivudine therapy.

Theoretical analysis of fluid mixing time in liquid-continuous impinging streams reactor

The mixing time of impact zone in liquid-continuous impinging streams reactor(LISR) is theoretically calculated by empirical model and modern micromixing model of the fluid mixing process, and the variation laws of macromixing time and micromixing time are quantitatively discussed. The results show that under a continuous and stable operating condition, as the paddle speed increases, the macromixing time and micromixing time calculated by the two models both decrease, even in a linkage equilibrium state. Simultaneously, as the paddle speed increases, the results figured by the two models tend to be consistent. It indicates that two models both are more suitable for calculation of mixing time in high paddle speed. Compared with the existing experimental results of this type of reactor, the mixing time computed in the speed of 1500 r/min is closer to it. These conclusions can provide an important reference for systematically studying the strengthening mechanism of LISR under continuous mixing conditions.

Physical activity, obesity and gastroesophageal reflux disease in the general population

AIM: To clarify the association between physical activity and gastroesophageal reflux disease (GERD) in nonobese and obese people. METHODS: A Swedish population-based cross-sectional survey was conducted. Participants aged 40-79 years were randomly selected from the Swedish Registry of the Total Population. Data on physical activity, GERD, body mass index (BMI) and the covariates age, gender, comorbidity, education, sleeping problems, and tobacco smoking were obtained using validated questionnaires. GERD was self-reported and defined as heartburn or regurgitation at least once weekly, and having at least moderate problems from such symptoms. Frequency of physical activity was categorized into three groups: (1) "high" (several times/week); (2) "intermediate" (approximately once weekly); and (3) "low" (1-3 times/mo or less). Analyses were stratified for participants with "normal weight" (BMI < 25 kg/m 2 ), "overweight" (BMI 25 to ≤ 30 kg/m 2 ) and "obese" (BMI > 30 kg/m 2 ). Multivariate logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs), adjusted for potential confounding by covariates. RESULTS: Of 6969 eligible and randomly selected individuals, 4910 (70.5%) participated. High frequency of physical activity was reported by 2463 (50%) participants, GERD was identified in 472 (10%) participants, and obesity was found in 680 (14%). There were 226 (5%) individuals with missing information about BMI. Normal weight, overweight and obese participants were similar regarding distribution of gender and tobacco smoking status, while obese participants were on average slightly older, had fewer years of education, more comorbidity, slightly more sleeping problems, lower frequency of physical activity, and higher occurrence of GERD. Among the 2146 normal-weight participants, crude point estimates indicated a decreased risk of GERD among individuals with high frequency of physical activity (OR: 0.59, 95% CI: 0.39-0.89), compared to low frequency of physical activity. However, after adjustment for potential confounding factors, neither intermediate (OR: 1.30, 95% CI: 0.75-2.26) nor high (OR: 0.99, 95% CI: 0.62-1.60) frequency of physical activity was followed by decreased risk of GERD. Sleeping problems and high comorbidity were identified as potential confounders. Among the 1859 overweight participants, crude point estimates indicated no increased or decreased risk of GERD among individuals with intermediate or high frequency of physical activity, compared to low frequency. After adjustment for confounding, neither intermediate (OR: 0.75, 95% CI: 0.46-1.22) nor high frequency of physical activity were followed by increased or decreased risk of GERD compared to low frequency among nonobese participants. Sleeping problems and high comorbidity were identified as potential confounders for overweight participants. In obese individuals, crude ORs were similar to the adjusted ORs and no particular confounding factors were identified. Intermediate frequency of physical activity was associated with a decreased occurrence of GERD compared to low frequency of physical activity (adjusted OR: 0.41, 95% CI: 0.22-0.77). CONCLUSION: Intermediate frequency of physical activity might decrease the risk of GERD among obese individuals, while no influence of physical activity on GERD was found in non-obese people.

EXPRESSION OF ICAM-1 AND LFA-1 MOLECULES IN RELATION TO RENAL ALLOGRAFT REJECTION IN RATS

Objective.The purpose of this study was to assess the renal graft expression of ICAM 1(intercellular adhesion molecule 1) and LFA 1(lymphocyte function associated antigen 1)molecule with relation to graft rejection. Methods.Rat kidney transplantation was performed according to the procedure of Kamada with some modification.Experimental rats were divided into 5 groups.The survival time of recipient rats and function of grafts after renal transplantation were observed.The sections of renal graft were stained for monoclonal antibody ICAM 1 and LFA 1, and then quantification of ICAM 1 and LFA 1 expression was accomplished by computer image analysis. Results.ICAM 1 and LFA 1 increased significantly in the renal allograft rejection group as compared with the non rejection groups(P<0 05). Conclusion.Both biopsy of renal graft and monitoring of ICAM 1 and LFA 1 are useful tools in diagnosing and treating acute rejection.

Agent-Based Network Modeling Study of Immune Responses in Progression of Ulcerative Colitis

Ulcerative colitis, an inflammatory bowel disease, is a chronic inflammatory disorder that results in ulcers of the colon and rectum without known etiology. Ulcerative colitis causes a huge public health care burden particularly in developed countries. Many studies suggest that ulcerative colitis results from an abnormal immune response against components of cornrnensal rnicrobiota in genetically susceptible individuals. However, understanding of the disease mechanisms at cellular and molecular levels remains largely elusive. In this paper, a network model is developed based on our previous study and computer simulations are perforrned using an agent-based network modeling to elucidate the dynamics of immune response in ulcerative colitis progression. Our modeling study identifies several important positive feedback loops as a driving force for ulcerative colitis initiation and progression. The results demonstrate that although immune response in ulcerative colitis patients is dominated by anti-inflarnrnatory/regulatory cells such as alternatively activated rnacrophages and type II natural killer T cells, proinflarnrnatory cells including classically activated rnacrophages, T helper 1 and T helper 17 cells, and their secreted cytokines tumor necrosis factor-α, interleukin-12, interleukin-23, interleukin-17 and interferon-γ remain at certain levels （lower than those in Crohn＇s disease, another inflammatory bowel disease）. Long-terrn exposure to these proinflarnrnatory components, causes rnucosal tissue damage persistently, leading to ulcerative colitis. Our simulation results are qualitatively in agreement with clinical and laboratory measurements, offering novel insight into the disease mechanisms.

The BUD2 mutation affects plant architecture through altering cytokinin and auxin responses in Arabidopsis

The ratio of auxin and cytokinin plays a crucial role in regulating aerial architecture by promoting or repressing axillary bud outgrowth. We have previously identified an Arabidopsis mutant bud2 that displays altered root and shoot architecture, which results from the loss-of-function of S-adenosylmethionine decarboxylase 4 （SAMDC4）. In this study, we demonstrate that BUD2 could be induced by auxin, and the induction is dependent on auxin signaling. The mutation of BUD2 results in hyposensitivity to auxin and hypersensitivity to cytokinin, which is confirmed by callus induction assays. Our study suggests that polyamines may play their roles in regulating the plant architecture through affecting the homeostasis of cytokinins and sensitivities to auxin and cytokinin.

Desilication kinetics of calcined boron mud in molten sodium hydroxide media

Desilication kinetics of calcined boron mud(CBM) occurring in molten sodium hydroxide media was investigated. The effects of factors such as reaction temperature and Na OH-to-CBM mass ratio on silicon extraction efficiency were studied. The results show that silicon extraction efficiency increases with increasing the reaction time and Na OH-to-CBM mass ratio. There are two stages for the desilication process of the calcined boron mud. The overall desilication process follows the shrinking-core model, and the first and second stages of the process were determined to obey the shrinking-core model for surface chemical reaction and the diffusion through the product layer, respectively. The activation energies of the first and second stages were calculated to be 44.78 k J/mol and 15.94 k J/mol, respectively.

Induction of IgA and sustained deficiency of cell proliferative response in chronic hepatitis C

AIM： In the present study, antibody and peripheral blood mononuclear cells （PBMC） proliferative responses against hepatitis C virus （HCV） antigens were evaluated in HCV chronically infected patients. METHODS： Paired serum and PBMC samples were taken six months apart from 34 individuals, either treated or not, and tested by enzyme-linked immunosorbent assay （ELISA） and carboxyfluorescein succinimidyl ester staining. RSULTS： Over 70% of the patients showed specific IgG and IgM against capsid, E1 and NS3, while HVR-1 was recognized by half of the patients. An increase in the levels of the anti-capsid IgM （P = 0.027） and IgG （P = 0.0006） was observed in six-month samples, compared to baseline. Similarly, a significantly higher percent of patients had detectable IgA reactivity to capsid （P = 0.017） and NS3 （P = 0.005） after six months, compared to baseline. Particularly, IgA against structural antigens positively correlated with hepatic damage （P = 0.036）. IgG subclasses evaluation against capsid and NS3 revealed a positive recognition mediated by IgG1 in more than 80% of the individuals. On the contrary, less than 30% of the patients showed a positive proliferative response either of CD4＋ or CD8＋ T cells, being the capsid poorly recognized. CONCLUSION： These results confirm that while the cellular immune response is narrow and weak, a broad and vigorous humoral response occurs in HCV chronic infection. The observed correlation between IgA and hepatic damage may have diagnostic significance, although it warrants further confirmation.

A ground reflection model for I-UWB signal propagation

Impulse systems do not undergo the multi-path destructive interference that manifests itself as Rayleigh fading prevalent in continuous wave systems, but rather show up as delayed replications of the direct impulse. In this paper, the model for impulse signals propagation over a plane earth is proposed. The condition for direct pulse and its replication overlapping each other was investigated. The model described here also takes into account the polarization of the transmission signals and the reflection coefficient of the plane, which was always neglected by previous approaches. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponents as the distance between transmitter and receiver (T-R) increasing.

Increase in neurokinin-1 receptor-mediated colonic motor response in a rat model of irritable bowel syndrome

AIM: Irritable bowel syndrome (IBS) is a functional bowel disorder. Its major symptom is bowel dysmotility, yet the mechanism of the symptom is poorly understood. Since the neurokinin-1 receptor (NK1R)-mediated signaling in the gut is important in the control of normal bowel motor function,we aimed to investigate whether the NK1R-mediated bowel motor function was altered in IBS, using a rat IBS model that was previously reported to show colonic dysmotility in response to restraint stress.METHODS: IBS symptoms were produced in male SpragueDawley rats by inducing colitis with acetic acid. Rats were left to recover from colitis for 6 d, and used for experiments 7 d post-induction of colitis. Motor activities of distal colon were recorded in vitro.RESULTS: The contractile sensitivity of isolated colon to a NK1R agonist [Sar9, Met(O2)11]-substance P (1-30 nmol/L)was higher in IBS rats than that in normal rats. After the enteric neurotransmission was blocked by tetrodotoxin (TTX, 1 μmol/L), the contractile sensitivity to the NK1R agonist was increased in normal colon but not in IBS rat colon. The NK1R agonist-induced contraction was not different between the two groups when the agonist was challenged to the TTX-treated colon or the isolated colonic myocytes. A nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME, 100 μmol/L) augmented the NK1R agonist-induced contraction only in normal rat colon.CONCLUSION: These results suggest that the NK1R-meidated colonic motor response is increased in IBS rats, due to the decrease in the nitrergic inhibitory neural component.

Spontaneous coal combustion producing carbon dioxide and water

Gas products from the process of coal oxidization and spontaneous combustion have been studied at different temperatures with FTI spectroscopic tests. With temperatures rising to about 30~100 ℃, water and carbon dioxide gas were formed and from about 105~150 ℃, carbon monoxide was produced. Using the DFT B3LYP method with a 6-311G basis set, the reaction system, where spontaneous combustion between coal and oxygen occurs and produces water and monoxide, has been studied, with the geometric configuration for all stagnation points on the potential reaction energy surface optimized. With a frequency analysis and an IRC method, transient formations were tested. Our results indicate that in the reaction of coal oxidization and spontaneous com-bustion producing carbon dioxide and water, oxygen molecules attack carbon atoms of the terminal of the propyl alcohol group on the lateral chain of benzene rings, which causes this propyl alcohol group to produce the acid (-CH2-CH2-COOH) group and water. This acid group continues its break up into carbon dioxide and the (-CH2-CH3) ethyl group. We have come to the conclusion that this water-and-carbon dioxide-production reaction is spontaneous, based on the observation of the energy released by the reaction.

Characteristics of hydrocarbon source rocks of No.3 buried-hill region in Nanpu Sag

Based on the data of 44 samples of hydrocarbon source rocks in Nanpu No.3 buffed-hill region, the kerogen type is judged through the pyrolysis and microscopic identification. At the same time, organic matter maturity and hydrocarbon generation threshold are studied by using vitrinite reflectance, pyrolysis yield and hydrocarbon abundance. Meanwhile the hydrocarbon expulsion threshold is calculated. And the characteristics of organic hydrocarbon generation and expulsion are preliminarily revealed and evaluated. The result shows that the No.3 buffed-hill region has abundant hydrocarbon source rocks with high content of organic carbon. And the primary types of kerogen are II, and lI 2. The hydrocarbon source rocks which passed biochemistry, thermolysis and thermal cracking have developed into the mature-postmature phase of different extents. And plenty of oil and gas were expelled out. It is believed the depth of oil-generating window is 3 600 m and the depth of hydro- carbon-expulsion threshold is 4 100 m. The comprehensive analysis indicates that Nanpu No.3 burried-hill region has a certain condition to generate hydrocarbon which is very promising in oil exploration and thus can become an important exploration and development target next.