谈如何使警犬技术的独特作用得到充分发挥

随着警犬技术自身不断地发展和完善,使用效益逐步提高,警犬技术在公安工作中的独特作用也日益明显,但其独特作用是否已经得到充分发挥了呢?笔者认为,目前我国警犬技术的作用距"充分发挥"还相差甚远.主要表现为:作为证据仍未得到法律的确认,参与侦办"大案"多、忽视了对"小案"的侦办,在各地区发挥的作用不均衡.究其原因,笔者认为主要有以下三个方面.     

Variability in mixing efficiency and laboratory analyses of a common diet mixed at 25 experiment stations

An experiment involving 25 experiment stations in the North Central and Southern regions (NCR-42 and S-288, respectively) was conducted to assess the degree of uniformity of diet mixing among stations and to assess the variability among station laboratories in chemical analysis of mixed diets. A fortified corn-soybean meal diet was mixed at each station using a common diet formula (except for vitamin and trace-mineral additions). The diet was calculated to contain 14% crude protein (CP), 0.65% Ca, 0.50% P, and 125 ppm Zn (based on 100 ppm added Zn). After mixing, samples were collected from the initial 5% of feed discharged from the mixer, after 25, 50, and 75% was discharged, and from the final 5% of discharged feed. The five samples were sent to the University of Kentucky, finely ground, and divided into subsamples. Each set of five subsamples from each station was distributed to three randomly selected stations for analysis of CP, Ca, P, and Zn (i.e., each station analyzed five diet sub-samples from three other stations). In addition, two commercial and two station laboratories analyzed composites of the five subsamples from each of the 25 mixed diets. Based on the laboratories that analyzed all diets, means were 13.5, 0.65, and 0.52%, and 115 ppm for CP, Ca, P, and Zn, respectively. Ranges of 11.8 to 14.6% CP, 0.52 to 0.85% Ca, 0.47 to 0.58% P, and 71 to 182 ppm of Zn were found among the 25 diet mixes. The coefficients of variation among the 25 diet samples for CP, Ca, P, and Zn were 4.3, 9.3, 4.1, and 17.4%, and among the 25 laboratories were 3.6, 12.5, 10.7, and 11.1%, respectively. Overall analyses of the five sub samples were, respectively, CP: 13.4, 13.6, 13.4, 13.5, and 13.4% (P < 0.06); Ca: 0.66, 0.67, 0.67, 0.66, and 0.67%; P: 0.50,0.51,0.51,0.50, and 0.50%; and Zn: 115, 116, 112, 113, and 120 ppm (P < 0.001). Diets were not uniformly mixed at all stations (station x sample No. was P < 0.08 for Ca and P < 0.01 for CP, P, and Zn). Among stations, the range of the five samples, expressed as a percentage of the mean and averaged for CP, Ca, P, and Zn, varied from +/- 1.1% (i.e., 98.9 to 101.0%) to +/- 12.9% (84.6 to 110.4%), with an overall average of +/- 5.2%. Neither type nor volume of mixers was related to mixing uniformity. The results suggest that uniformity of diet mixes varies among experiment stations, that some stations miss their targeted levels of nutrients (especially Zn), and that the variability among experiment station laboratories in analysis of dietary Ca, P, and Zn in mixed diets is quite large.     

Screening for plant transporter function by expressing a normalized Arabidopsis full-length cDNA library in Xenopus oocytes

Background  

We have developed a functional genomics approach based on expression cloning in Xenopus oocytes to identify plant transporter function. We utilized the full-length cDNA databases to generate a normalized library consisting of 239 full-length Arabidopsis thaliana transporter cDNAs. The genes were arranged into a 96-well format and optimized for expression in Xenopus oocytes by cloning each coding sequence into a Xenopus expression vector.     

神经网路模式在流量之预测

本文以倒传递神经网路模式,进行长期流量预测之应用研究,并以台湾中部德基水库上游松茂流量站历年观测资料进行探讨。初步得到预测结果与实测值比较尚有一倍以上的误差。但以神经网路之潜在应用潜力,寻找系统化网路参数值建立方法以得到更精确预测结果之经验,为寻人相当值得继续研究之课题。     

Chromosome location of the gene for the hulled character in the Tibetan weedrace of common wheat

The hulled character of the Tibetan weedrace ( Triticum aestivum var. tibetanum) was found to be governed by a single dominant gene on the short arm of chromosome 2D. The hulled character gene may be identical to the gene Tg derived from Aegilops tauschii.     

Cytogenetic studies of the interspecific hybrids between Hystrix longearistata in Japan and Hystrix duthiei in China

Cytogenetic studies of Hystrix duthiei (2n=28) from China, Hystrix longearistata (2n=28) from Japan and their artificial hybrids were carried out. The F1 hybrids showed a very high degree of bivalent pairing at the meiotic Metaphase-I. No multivalents were found. Partial fertility of the hybrids was observed. The results indicated that they shared two highly homologous genomes and were closely related.     

The Chemically Highly Diversified Metabolites from the Red Sea Marine Sponge Spongia sp.

A polyoxygenated and halogenated labdane, spongianol (1); a polyoxygenated steroid, 3β,5α,9α-trihydroxy-24S-ethylcholest-7-en-6-one (2); a rare seven-membered lactone B ring, (22E,24S)-ergosta-7,22-dien-3β,5α-diol-6,5-olide (3); and an α,β-unsaturated fatty acid, (Z)-3-methyl-9-oxodec-2-enoic acid (4) as well as five known compounds, 10-hydroxykahukuene B (5), pacifenol (6), dysidamide (7), 7,7,7-trichloro-3-hydroxy-2,2,6-trimethyl-4-(4,4,4-trichloro-3-methyl-1-oxobu-tylamino)-heptanoic acid methyl ester (8), and the primary metabolite 2’-deoxynucleoside thymidine (9), have been isolated from the Red Sea sponge Spongia sp. The stereoisomer of 3 was discovered in Ganoderma resinaceum, and metabolites 5 and 6, isolated previously from red algae, were characterized unprecedentedly in the sponge. Compounds 7 and 8 have not been found before in the genus Spongia. Compounds 1–9 were also assayed for cytotoxicity as well as antibacterial and anti-inflammatory activities.     

Neuroprotective effects of the citrus flavanones against H2O2-induced cytotoxicity in PC12 cells

The citrus flavanones hesperidin, hesperetin, and neohesperidin are known to exhibit antioxidant activities and could traverse the blood-brain barrier. H2O2 formation induces cellular oxidative stress associated with neurodegenerative diseases. In this study, protective effects of pretreatments (6 h) with hesperidin, hesperetin, and neohesperidin (0.8, 4, 20, and 50 microM) on H2O2-induced (400 microM, 16 h) neurotoxicity in PC12 cells were evaluated. The results showed that hesperetin, hesperidin, and neohesperidin, at all test concentrations, significantly ( p < 0.05) inhibited the decrease of cell viability (MTT reduction), prevented membrane damage (LDH release), scavenged ROS formation, increased catalase activity, and attenuated the elevation of intracellular free Ca2+, the decrease of mitochondrial membrane potential (except those of 0.8 microM neohesperidin-treated cells) and the increase of caspase-3 activity in H2O2-induced PC12 cells. Meanwhile, hesperidin and hesperetin attenuated decreases of glutathione peroxidase and glutathione reductase activities and decreased DNA damage in H2O2-induced PC12 cells. These results first demonstrate that the citrus flavanones hesperidin, hesperetin, and neohesperidin, even at physiological concentrations, have neuroprotective effects against H2O2-induced cytotoxicity in PC12 cells. These dietary antioxidants are potential candidates for use in the intervention for neurodegenerative diseases.