氧化钒薄膜制备与特性研究

用磁控反应溅射法制备出具有红外敏感特性的氧化钒薄膜,进行了薄膜光电特性的测试.通过AFM和XRD对薄膜的结构和特性进行分析研究,并给出了沉积参数对薄膜性能的影响.     

ALC-OFDM系统中的ACMS新选择准则

针对新一代宽带卫星通信,建立了自适应低密度奇偶校验码(LDPC)编译码的正交频分复用(ALC-OFDM)传输系统结构与信道模型.在分析固定编码调制方式基础上,提出了一种加权信噪比(SNR)的自适应编码调制方案(ACMS)选择新准则,使每种编码调制方案对应着一个信道平均信噪比范围,可以有效找出使系统吞吐量最优的信噪比切换门限值.仿真结果表明:在系统的误比特率(BER)满足要求的情况下,对比各种加权准则,加权得到的SNR越大,采用该准则的系统吞吐量越大;当系统吞吐量都达到最大值时,采用3种加权方式的信噪比切换门限比传统准则至少降低了2 dB.     

收发频谱不一致条件下的变换域通信系统基函数设计

针对变换域通信系统收发频谱不一致条件下接收端基函数存在错误而导致系统性能下降的问题,提出了具有信噪比次优解的基函数设计方法。详细分析了系统的收发过程,在此基础上研究了系统误码率的最优化与接收端基函数组成的关系,在收发频谱不一致而无法获得最优基函数的情况下,采用类似等增益合并的方法设计了接收端基函数,从而以该基函数完成数据解调。仿真结果表明:在单用户和多用户环境下,当收发频谱不一致比例较高时,接收端采用类似等增益合并的基函数设计方法可以完成系统的次优接收。在单用户环境下,相比不一致比例为40%时,次优接收方法的信噪比增益可达4dB左右,并且发送端频谱可用率为80%时,相比最优接收法的信噪比损失在1.5dB以内。     

基于轮廓线局部描述符的三维人脸识别

提出了一种基于等测地轮廓线的局部描述符来识别三维人脸。首先对三维人脸数据进行预处理, 得到统一的人脸区域并进行姿态归一化; 然后根据测地距离提取到鼻尖点相同距离的点组成等测地轮廓线, 对轮廓线进行重采样, 并对轮廓线上每个采样点的邻域提取局部描述符; 最后在建立测试人脸和库集人脸的点对应关系后进行局部描述符的加权融合和比较, 给出最终识别结果。算法在FRGC(face recognition grand challenge)v2. 0数据库上进行测试, 实验结果表明该方法具有较好的识别性能。     

Microbiologic contamination during dental radiographic film processing

Arteriosclerotic intimal proliferation is one of the main long-term complications of organ transplantation. Low-molecular-weight, heparin-like molecules prevent myointimal proliferation in arterial wall injury and limit rejection in skin allografts. Cyclosporin limits rejection but has no major effect on intimal proliferation. Therefore, an experimental protocol was designed to test whether heparin-like molecules interacted with low doses of cyclosporin to prevent arterial wall immune system injury and response in a model of arterial graft rejection in normotensive and hypertensive rats. Aortic allografts were performed in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) normotensive control rats. Four groups of 10 allografted (SHR and WKY) rats were used: one group was treated with placebo, one with low doses of cyclosporin (2 mg/kg body wt per day), one with low-molecular-weight, heparin-like molecule (1 mg/kg body wt per hour), and one with low doses of cyclosporin plus low-molecular-weight, heparin-like molecule. Ten SHRs and 10 WKYs were isografted and served as the control groups. All rats were killed 8 weeks after aortic grafting. Structural parameters of the grafted segment were measured by morphometric analysis on formalin-fixed sections with specific stains. The classical signs of immune system injury and response were present in the untreated allografts in SHRs and WKYs: inflammatory infiltration of the adventitia, medial injury, and intimal proliferative response. Low doses of cyclosporin had a significant beneficial effect on immune medial injury by increasing medial thickness and the number of remaining smooth muscle cells and decreasing the extracellular matrix injury. Cyclosporin had no protective effect on intimal proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)     

Functional nucleotide excision repair is required for the preferential removal of N-ethylpurines from the transcribed strand of the dihydrofolate reductase gene of Chinese hamster ovary cells

Cervid species represent a growing livestock enterprise in the United States of America (USA). The zoonotic threat of bovine tuberculosis (Mycobacterium bovis) is the only significant public health risk posed by this alternative livestock industry. This paper examines the potential sources of tuberculosis exposure as related to public health and compares and contrasts the status of tuberculosis in Cervidae with the situation in the cattle industry in the USA. Based on the existing prevalence of the disease and the limited potential of human exposure to infected meat or meat products, bovine tuberculosis in Cervidae poses a minimal threat to public health. The only significant public health concern is exposure to infected free-ranging cervids of hunters who field-dress carcasses and may unknowingly incise tuberculous lesions. This risk is mitigated only by the small size of the cervid population at risk when compared to the general population of cervids hunted yearly.     

Criterion validity and the utility of reactive and proactive aggression: comparisons to attention deficit hyperactivity disorder, oppositional defiant disorder, conduct disorder, and other measures of functioning

Human immunodeficiency virus (HIV)-associated nephropathy (HIVAN) is a clinicopathologic entity that includes proteinuria, azotemia, focal segmental glomerulosclerosis or mesangial hyperplasia, and tubulointerstitial disease. The incidence of HIVAN is increased in black patients and variable depending on the age and geographic area. The objective of this study was to describe relevant clinical and pathological findings in 30 children with HIVAN followed at the Children's National Medical Center in Washington, D.C. Our experience of the last 12 years showed a spectrum of HIVAN that seems to be coincident with the degree of acquired immunodeficiency syndrome (AIDS) symptomatology. By renal sonograms and frequent urinalysis, we identified children undergoing the early stages of HIVAN with enlarged echogenic kidneys, proteinuria, and "urine microcysts". HIVAN did not necessarily progress rapidly to end-stage renal disease. Nephrotic syndrome or chronic renal insufficiency were late manifestations of HIVAN. Children with HIVAN were likely to develop transient electrolyte disorders, heavy proteinuria, and acute renal failure due to systemic infectious episodes or nephrotoxic drugs. HIVAN was associated with other HIV-induced illnesses and high mortality rates. Early detection and careful clinical follow-up of children with HIVAN may reduce the incidence of renal-cardiovascular complications and improve their quality of life.     

协同业务过程与需求的建模及一致性验证

自底向上建模方法中的业务过程由不同组织开发,无法在设计阶段就预见其潜在的所有交互可能.因此,在实际协作中,建立协同业务过程可能与参与组织期望的系统功能和特性不一致.为此,提出一种协同业务过程与需求的建模及一致性验证方法.首先,引入并发操作符,提供一种通过组合参与组织的业务过程构建协同业务过程方法;然后,扩展目标模型,提出需求依赖图来建模参与组织的需求;最后,基于模型检测技术提出协同业务过程与需求一致性检测方法.重点解决了将协同业务过程转换为表达能力相同FSP进程规约和参与组织需求转换为LTL公式这两个问题.通过对典型的协同业务过程集阐述提出方法的有效性,并对方法分析效率进行评价,结果表明：相对已有工作,提出方法能够更加有效地用于协同业务过程与需求的一致性分析.     

Antimicrobial Peptide Mimetics Based on a Diphenylacetylene Scaffold: Synthesis,Conformational Analysis,and Activity

Mimics of natural antimicrobial peptides are promising compounds to fight the rising threat of multi-drug resistant bacteria. Here we report the design, synthesis and conformational analysis of a new class of antimicrobial peptide mimetics incorporating a diphenylacetylene scaffold. Within a small set of compounds, we observe a correlation between amphiphilicity, the efficiency of partitioning into negatively charged membranes and antibacterial activity. The most amphiphilic compound, which contains four isoleucine residues and four lysine residues, displays species-selective antibacterial activity (most active against Bacillus subtills) and low haemolytic activity. Solution-phase conformational analysis of this compound indicates that a defined structure is adopted in the presence of negatively charged phospholipid membranes and aqueous 2,2,2-trifluoroethanol but not in water. A conformation model indicates that the cationic and hydrophobic functional groups are segregated. These results may inform the development of highly selective antimicrobial peptide mimetics for therapeutic applications.