热板温度的控制要求与检测方法的探讨

综述了目前国内热熔焊机热板温度控制存在的常见问题,分析了产生问题的主要原因,为明确相关标准对热板温度控制要求的规定,探讨了全自动热熔焊机热板温度的控制要求和检测方法。     

一种车流量自适应交通灯控制系统的实现

介绍了一种基于555定时器和74LS161计数器的流量自适应交通灯控制系统。该系统采用车流量检测电路实现交通灯亮灭持续时间的自适应控制,较好地解决了当前多数交通灯控制系统存在的不能根据道路上车流量的情况自适应调节的缺点。该系统经组装、调试,并在路口试验。效果良好。     

Leaf blade anatomy and ultrastructure of six <i>Simira</i> species (Rubiaceae) from the Atlantic Rain Forest,Brazil

Simira is a predominantly woody Neotropical genus comprising 41 taxa, 16 of which occur in Brazil and eight of them in the southeastern region of Brazil. Leaf blades of Simira eliezeriana Peixoto, S. glaziovii (K. Schum.) Steyerm., S. grazielae Peixoto, S. pikia (K. Schum.) Steyerm., S. rubra (Mart.) Steyerm., S. sampaioana (Standl.) Steyerm. were collected in the southeastern region of Brazil and fixed according to usual methods for light and electron microscopy. The leaf blades show typical characteristics of the Rubiaceae family as dorsiventral mesophyll and paracytic stomata. The presence of two bundle sheaths that extend to the upper epidermal layer, prismatic crystal and crystal-sand, alkaloids in the mesophyll and the organization micromorphological of the outer periclinal wall are considered characteristics representative for the genus. This study also demonstrates some leaf blade characteristics that can be used to Simira species identification (leaf surface, domatia types, epicuticular wax types and patterns of epidermis anticlinal cell walls).     

分布式环境下全局序列模式挖掘技术研究

由于分布式环境下挖掘全局序列模式常常产生过多候选序列,加大了网络通信代价.为此提出一种基于分布式环境下的全局序列模式快速挖掘算法.该算法将各站点得到的局部序列模式压缩到一种语法序列树上,避免了重复的序列前缀传输;基于合并树中节点序列规则和简单的特点,提出一种项扩展和序列扩展剪枝策略,有效地约减了候选序列,减少了网络传输量,从而快速生成全局序列模式.理论和实验表明,在大数据集环境下该算法性能优越,能够有效地挖掘全局序列模式.     

Stereological estimation of surface area and barrier thickness of fish gills in vertical sections

Previous morphometric methods for estimation of the volume of components, surface area and thickness of the diffusion barrier in fish gills have taken advantage of the highly ordered structure of these organs for sampling and surface area estimations, whereas the thickness of the diffusion barrier has been measured orthogonally on perpendicularly sectioned material at subjectively selected sites. Although intuitively logical, these procedures do not have a demonstrated mathematical basis, do not involve random sampling and measurement techniques, and are not applicable to the gills of all fish. The present stereological methods apply the principles of surface area estimation in vertical uniform random sections to the gills of the Brazilian teleost Arapaima gigas. The tissue was taken from the entire gill apparatus of the right‐hand or left‐hand side (selected at random) of the fish by systematic random sampling and embedded in glycol methacrylate for light microscopy. Arches from the other side were embedded in Epoxy resin. Reference volume was estimated by the Cavalieri method in the same vertical sections that were used for surface density and volume density measurements. The harmonic mean barrier thickness of the water‐blood diffusion barrier was calculated from measurements taken along randomly selected orientation lines that were sine‐weighted relative to the vertical axis. The values thus obtained for the anatomical diffusion factor (surface area divided by barrier thickness) compare favourably with those obtained for other sluggish fish using existing methods.     

Analytical TEM study of annealed nanocrystalline cobalt–phosphorous electrodeposits

Investigation of thermal stability of two nanocrystalline Co–P alloys shows that P atoms segregate to the grain boundaries upon annealing until precipitation of Co₂P and CoP precipitates takes place. The P-rich precipitates formed have been investigated by analytical transmission electron microscopy to obtain statistical results of precipitate size, volume fraction and spatial distribution. Electron spectroscopic imaging maps show that the P-rich precipitates are 33 ± 9 nm in Co–1.1at.%P and 33 ± 12 nm in Co–3.2at.%P. The main differences between the alloys are the precipitate size distribution (Co–3.2at.%P having broader distribution) and precipitate volume number density (Co–3.2at.%P has 1.8 times more precipitates than Co–1.1at.%P). The volume fraction of precipitates is 3.0% in Co–1.1at.%P and 4.4% in Co–1.1at.%P. Most of the precipitates are of nearly spherical or slightly elongated shape, and only a few have a platelet-like shape as expected from previous tomographic atom probe measurements. Due to the truncation and projection effects, the composition of the precipitates could not be determined.     

Effects of substitutions in the binding surface of an antibody on antigen affinity

The interactions between the Fab and single-chain Fv (scFv) fragments of an antibody (NC10) and its antigen, influenza virus neuraminidase, were analysed in the crystal structures of the Fab-neuraminidase and scFv-neuraminidase complexes. To investigate the contribution to binding made by cavities, salt links and hydrogen bonds in the antibody- antigen interface, 14 single amino acid replacements were made at six contact residues in the scFv fragment by site-directed mutagenesis. The binding affinity of each mutant scFv antibody for neuraminidase was determined with a BIAcore optical biosensor. Four of the mutations resulted in large changes in the free energy of binding to neuraminidase (deltadeltaG > 1 kcal/mol) and together may account for approximately 70% of the free energy of binding. Hence these data support the theory that a small number of residues form the 'functional epitope' and are most important for binding of NC10 to neuraminidase. The salt link between antibody residue (Asp)H56 and (Lys)N432 from neuraminidase was demonstrated to be important for affinity, since substitution of (Asp)H56 with Asn caused a large reduction in the free energy of binding (deltadeltaG = +2.8 kcal/mol). Hydrogen bonds provided by (Tyr)L32 and (Asp)H56 were also important for binding: mutation of (Tyr)L32 to Phe resulted in a significant reduction in binding affinity (deltadeltaG = +1.7 kcal/mol). Disruption of hydrophobic interactions (van der Waals contacts) led to significant reductions in affinity also ((Tyr)H99 to Ala, deltadeltaG = +1.5 kcal/mol; (Leu)L94 to Ala, deltadeltaG > +3.0 kcal/mol). An attempt to increase binding affinity by filling a cavity in the interface with a larger antibody side chain was unsuccessful, as the free energy gained by new antibody-antigen interactions did not compensate for the removal of cavity-bound water molecules.      

Molecular parameters of type IV alpha-internexin and type IV-type III alpha-internexin-vimentin copolymer intermediate filaments

During neuronal development, a dynamic replacement mechanism occurs in which the type VI nestin and type III vimentin intermediate filament proteins are replaced by a series of type IV proteins beginning with alpha-internexin. We have explored molecular details of how the type III to type IV replacement process may occur. First, we have demonstrated by cross-linking experiments that bacterially expressed forms of alpha-internexin and vimentin form heterodimer molecules in vitro that assemble into copolymer intermediate filaments. We show using a urea disassembly assay that alpha-internexin molecules are likely to be more stable than those of vimentin. Second, by analyses of the induced cross-links, we have determined the axial lengths of alpha-internexin homodimer and alpha-internexin-vimentin heterodimer molecules and their modes of alignments in filaments. We report that these dimensions are the same as those reported earlier for vimentin homopolymer molecules and, by implication, are also the same for the other neuronal type IV proteins. These data suggest that during neuronal development, alpha-internexin molecules are readily assimilated onto the pre-existing vimentin cytoskeletal intermediate filament network because the axial lengths and axial alignments of their molecules are the same. Furthermore, the dynamic replacement process may be driven by a positive equilibrium due to the increased stability of the alpha-internexin network.     

4-Defect repair of grade 4 cystocele

PURPOSE: The 4-defect repair of grade 4 cystocele corrects discrete and severe deficiencies of vesicourethral support. We describe this technique used during pelvic reconstruction in 130 women. MATERIALS AND METHODS: During a 3-year period 130 patients (age range 35 to 96 years) underwent repair of grade 4 cystocele using the 4-defect repair technique. Cystocele repair had been performed in 60 patients (46%) and hysterectomy had been performed in 85 (65%). A "goalpost incision" is used in the vaginal wall to facilitate separation of the wall from underlying perivesical fascia, entry into the retropubic space, and exposure of the urethropelvic ligament, cardinal ligament and perivesical fascia. The 4 polypropylene sutures are used to provide an anterior vaginal wall sling which is modified to incorporate perivesical fascia and cardinal ligaments. Central defect repair is achieved by approximation of the cardinal ligaments and midline plication of the perivesical fascia over absorbable mesh. RESULTS: A total of 112 patients were available for followup which ranged from 6 to 42 months (mean 21). Repair of grade 4 cystocele was accompanied by other transvaginal repairs in 94 patients (83%), including rectocele repair in 81, hysterectomy in 22 and enterocele repair in 31. Of the patients 92% had excellent objective and subjective results for anatomical cystocele repair. Of the patients with preoperative stress urinary incontinence 90% had excellent or good subjective results. De novo urge incontinence was seen in 7% of patients. CONCLUSIONS: The 4-defect repair technique relies on anatomical restoration of 4 distinct deficiencies of pelvic support and is highly effective for relief of symptoms of grade 4 cystocele.