IDEFO功能建模及其在计算机辅助夹具设计中的应用

从系统建模的角度,以计算机辅助夹具设计(CAFD)系统为例,采用IDEFO方法建立CAFD系统的功能模型,并以此为依据设计了系统的总体结构,为高效地建立计算机辅助夹具设计系统提供了实现方法.     

电场驱动纳米Fe0在不同介质中的迁移行为研究

选取四种不同介质(100%石英砂、75%石英砂/25%高岭土、50%石英砂/50%高岭土和100%高岭土),探讨了黄原胶分散的纳米Fe~0在不同介质中的迁移行为。纳米材料投加点设置在介质填充池中间靠近阳极电解池的位置。研究发现,采用该实验装置,100%石英砂的处理中电渗流量最大,这与其较大的孔隙和渗透性有关,加入高岭土的处理中电渗流量较小且各处理流量相当。纳米Fe~0在石英砂中的迁移高于加入高岭土的处理,大部分纳米Fe~0集聚在靠近投加口的部分,在远离投加口的部分铁逐渐由Fe2+向Fe3+转化。100%高岭土中纳米Fe~0的迁移高于混合介质处理,这与其较高的电流强度有关。纳米Fe~0在电动迁移过程中很容易发生溶解和转化,其在高岭土中的迁移是以离子态进行的。μ-XANES(微束X射线近边分析)的分析结果证实电场驱动下高岭土中的铁主要以纤铁矿和磁铁矿形式存在。     

Sequences of the 3′ Halves of the Genomes of Barley Yellow Dwarf Virus-PAV cpA Isolates that Vary in Symptom Severity

Barley yellow dwarf virus (BYDV)-PAV isolates from USA have been separated into two distinct clusters (Chay et al. (1996) Virology 219: 57013;65; Chay et al. (1996) Phytopathology 86: 370013;377). Following this finding we have shown that BYDV-PAV is divided into two groups cpA and cpB based on their coat protein gene sequence, and distinct host preferences (Mastari et al. (1998) Phytopathology 88: 818013;821). We have sequenced the complete 30"> half of the genomes of two lethal and two mild cpA isolates and compared them with those of several known PAV cpA isolates to assess variability and locate potential determinants of severity. Open reading frames (ORFs) 3, 4, 5, 6 and the 30"> untranslated regions had different percent homologies between isolates: ORF5 (92013;97%), ORF3 (88013;98%) 30">-translational enhancer (87013;100%) ORF4 (85013;99%), 30"> untranslated region (72013;97%) and ORF6 (61013;99%). In contrast to the mild isolates, the field-lethal isolates (FHv1 and FHv2) fell into the same cluster, regardless of the genomic region analysed. The isolates FHv1 and FHv2 differed from mild isolates by eight amino acid substitutions in ORFs 3 and 4, and insertions in ORF5. Four amino acid substitutions in the 17-kDa protein encoded by ORF4 caused a change in local net charge in the field-lethal isolates. Two insertions of four amino acids were identified in the C-terminal half of ORF5 of the field-lethal isolates, but were not present systematically in all lethal isolates analysed. The potential relationships of these differences in predicted amino acid sequences to disease severity are discussed.     

纳米Fe^0／Fe_3O_4复合体系对溶液中PCB77的降解研究

研究了纳米Fe^0与纳米Fe_3O_4。单一与复合体系对溶液中PCB77的降解动力学,以及影响降解效率的不同因素。结果表明,投加纳米Fe^0对PCB77有显著的降解效果,反应240min后PCB77残留率为8．94％;投加纳米Feo同时配以不同比例的纳米Fe_3O_4。能明显影响PCB77的降解速率,纳米Fe^0／Fe_3O_4投加比例为1：0．1、1：0．2和1：1时,PCB77的残留率分别为6．46％、10．23％和38．20％。溶液pH对纳米FFe^0／Fe_3O_4复合体系降解PCB77具有较大的影响,当溶液pH为6．8时,纳米Fe^0／Fe_3O_4复合体系降解PCB77的效果最好。纳米Fe^0／Fe_3O_4复合体系对PCB77的降解是一个还原脱氯的过程,随着PCB77残留率的减小,氯离子浓度不断增大,同时反应体系中氧化还原电位不断降低。研究结果将为环境中残留PCBs提供一种高效去除方法,并为PCBs污染水体和土壤的修复提供理论依据。     

基于辐射和温度的ET0模型在吐鲁番地区的比较与修正

利用吐鲁番地区3个气象站2000—2015年逐日气象资料,以FAO-56 Penman-Monteith(FAO-56 PM)模型为标准,对6种ET_0模型(M-A模型、P-T模型、M-H模型、H-S模型、Traj模型和B-H模型)进行评价并修正,采用均方根误差(RMSE)、绝对平均误差(MAE)、平均相对误差(MRE)评价指标和Wilcoxon非参数检验法比较年、月尺度上各模型修正前后的估算精度,以筛选适用吐鲁番地区ET_0简化估算模型。结果表明:吐鲁番地区ET_0的主要影响因子是R_s(太阳辐射),其次是e_s(饱和水汽压)和R_n(作物表面净辐射);修正前,年尺度上,M-H模型的估算精度最高;月尺度上,各模型误差较大且与FAO-56 PM模型存在显著差异,适用性较差;修正后,各模型在年、月尺度上的精度均有明显提高,无显著差异,其中修正后的P-T、M-H和B-H模型估算精度最高,可作为吐鲁番地区ET_0简化估算模型。     

Crop productivity under differently lopped canopies of multipurpose trees in Central Himalaya, India

Ficus species are multipurpose trees well known by rural populations in Sahelian and Sudanian zones of Africa. Their uses are well documented but their amenability for vegetative propagation has not been extensively studied. This paper compares the rooting ability of stem and aerial root cuttings from thirteen Ficus species found in West Africa. It highlights the differences between species belonging to the sub-genera Sycomorus and Urostigma. The former show no capacity to propagate from cuttings whereas the latter, with epiphytic development, can be propagated by cuttings, although this capacity varies among species. Thus, F. thonningii, F. leprieurii and F. ovata are easily propagated, while F. platyphylla and F. elasticoides are propagated with difficulty. The rooting capacity also varies depending on the cutting material used. It decreases in the following order: long leafless hardwood cuttings (pole) > nodal cuttings > apical cuttings. Rooting potential increases when the cuttings are harvested towards the end of the dry season(March to May). Aerial root can be used for cuttings in all species of the sub-genus Urostigma. The capacity of root cuttings to regenerate is greatest when cuttings are collected at the beginning of the dry season (November). In this case, wound-induced adventitious roots arise at the basal end of the cutting while de novo buds are developed from the cambium at the distal end. The subsequent morphological development is identical to that of a stem cutting. These results clarify and allow the optimal use of the knowledge and methods developed by the indigenous people of the Sahel and could assist and promote fig tree (Ficus sp.) domestication in the dry tropics.This revised version was published online in November 2005 with corrections to the Cover Date.     

Milk Protein Polymorphism in Kangayam Cattle

This paper reports the milk protein polymorphism, the allele frequencies of variants and the possible linkages among various combinations of milk protein phenotypes in the Kangayam cattle of south India. Milk samples from 156 Kangayam cows were typed by starch gel and polyacrylamide gel electrophoresis for caseins and whey proteins, respectively. All the four milk protein components studied, 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">_s1-casein, 0174220k7w/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-casein, 0174220k7w/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-lactoglobulin and 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-lactalbumin, exhibited polymorphism with high allele frequencies of 0.9231±0.0151 for 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">_s1-casein C, 0.9263±0.0148 for 0174220k7w/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-casein A, 0.9135±0.0159 for 0174220k7w/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-lactoglobulin B and a relatively high frequency of 0.6218±0.0275 for 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-lactalbumin A. The mean heterozygosity estimated over all the four milk protein loci was 0.2420. Genetic equilibrium was observed among all the loci studied, except 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-lactalbumin. Linkage analysis confirmed the non-independence between 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">_s1- and 0174220k7w/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-caseins and between caseins and 0174220k7w/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-lactalbumin phenotypes.     

Mutant induction through adventitious buds of Kohleria

Summary Freshly cut leaves of Kohleria eriantha and K. x 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">Longwood0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> were exposed to a wide range of gamma irradiation doses and allowed to root and form adventitious buds. K. Eriantha could not be successfully propagated from leaf half cuttings. 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">Longwood0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> produced a small number of adventitious plantlets as compared to other Gesneriads. Colchicine treatments reduced leaf half survival in 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">Longwood0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> by more than 50%. Leaf halves exposed to low and moderate doses of gamma irradiation showed increased overall plantlet production compared to nonirradiated leaf halves.Of the mutation parameters calculated, the 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">number of mutants per 100 surviving leaf halves0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> appears to be the most useful since it relates the number of mutants within a dose to the number of surviving leaf halves, the number of mutants to the number of plants produced, and the number of mutants within doses to control values.Using the criteria, 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">number of mutants per 100 surviving leaf halves0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">, optimum production of all mutants, of useful and of dwarf mutants was obtained at 2.5 kR for noncolchicine treated leaf halves and 1.5 to 3.0 kR for colchicine treated leaf halves.Of the adventitious plantlets produced, 13.8% were classified as mutant types. Mutant plants were found in radiation dose levels up to 5.5 kR. The array of mutants produced was skewed toward 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">plant habit0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> and 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">flower characteristic0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> mutants with several 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">leaf characteristic0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">, 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">lethal0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0">, and 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">polyploid0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> mutants observed. A high frequency of mutants, 10 of 93 plants, occurred in the nonirradiated controls. Four sectorial chimeras were identified from both control and irradiation exposed groups. Several potentially useful flower color and dwarf mutants have been selected for further study. Adventitious buds may have developed from callus at petiole and leaf-vein bases. Colchicine treatments severely inhibited adventitious plantlet production and because of this could not be used as a criterion to identify the origin of adventitious buds. Conclusive determination of the organogenesis of adventitious buds from 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">Longwood0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> leaf halves could not be made. Mutant plantlets formed from adventitious buds on detached leaf halves of 0/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">Longwood0/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> appear to arise from single cells as has been found with other Gesneriads.Scientific Journal Series Article No. 10 330 of the Minnesota Agricultural Experiment Station.     

Crossability relationships of andean potato varieties of three ploidy levels

Summary The formation of triploids in 4x×2x crosses was studied in primitive potato varieties from the Andes of Peru and Bolivia. Triploid frequencies were as high as 80013;100% in some crosses, although the actual number of seeds was low. The 08446833/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">triploid block08446833/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> varied according to the tetraploid parent, and was never entirely absent. The likelihood of triploid formation was studied in 4x×2x crosses where pollen from both tetraploids and diploids of known genotype was used. Even though the diploids were chosen for their non-production of 2n gametes, as detected in pollen grain size, 66% of the hybrids were tetraploid. The amount and probability of gene-flow between the tetraploid and diploid gene-pools, either directly through 2n gametes or through 08446833/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">triploid bridges08446833/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> was examined. Most of the 20 cultivars of S. x chaucha produced seed in crosses with tetraploids and diploids, although the fertility of the latter crosses was four times higher. The female fertility of some of the triploids thus allows them to exchange genes with the tetraploids and diploids, although gene-flow occurs more rapidly through direct transfer from diploids to tetraploids via 2n gametes.     

Berberine attenuates lipopolysaccharide-induced impairments of intestinal glutamine transport and glutaminase activity in rat

Berberine was reported to protect against the intestinal injury and improve the survival rate in sepsis, and glutamine deficiency was considered to be correlated with mortality in sepsis. We found that berberine pretreatment ameliorated lipopolysaccharide-induced direct intestinal injury and mucosal hypoplasia and attenuated impairments of intestinal glutamine transport and glutaminase activity, B⁰AT1 mRNA and protein expressions, and glutaminase protein expression. These findings showed the first time that berberine pretreatment could improve intestinal recovery and attenuate the impairment of glutamine transport and glutaminase activity in rat sepsis. This might be one of the mechanisms for the beneficial effect of berberine on sepsis.