Retarded leaching of nitrate measured in monolith lysimeters in south-east Nigeria

At Onne in South-east Nigeria, drainage water was collected from four monolith lysimeters and analysed for nitrate. The lysimeters contained an acid sandy loam. At the start of the first rainy season two lysimeters received urea labelled with ¹⁵NO₃^– and two received no nitrogen fertilizer; all four were uncropped in the first year.
The peak concentrations of ¹⁵NO₃^– and of unlabelled (soil) NO₃^– were found after 2.5 pore volumes of water had passed through the lysimeters. Using the same soil in the laboratory after fine sieving, the peak concentration of tritiated water was found at 1 pore volume whereas nitrate leaching was retarded. The pattern of nitrate leaching was well described by miscible and immiscible models which included an adsorption coefficient for nitrate. Over the 2 years 81.4% of the ¹⁵N added at the start of the first rainy season was recovered in the drainage water.     

Polynuclear aromatic hydrocarbons,steroids and carcinogenesis

In addition to the electronic factors, there is a steric factor responsible for the carcinogenicity of polynuclear aromatic hydrocarbons. A carcinogenic polynuclear aromatic hydrocarbon must bear steric resemblance to steroids. One possible implication to this requirement for carcinogenicity is that these hydrocarbons may act on the same sites as steroid hormones.     

Unilateral laryngeal paralysis in a cat

A case of unilateral laryngeal paralysis in a cat is described which presented with signs of nasal discharge and dyspnoea. The condition is compared with laryngeal paralysis as seen in the horse and dog.     

转基因抗病毒病四倍体西瓜的培育

利用西瓜花叶病毒2号(WMV-2)外壳蛋白(CP)基因、小西葫芦黄花叶病毒(ZYMV)复制酶(NIb)基因和黄瓜花叶病毒(CMV)复制酶基因构建三价基因的植物表达载体,通过农杆菌介导转化四倍体西瓜植株,经分子检测证明目的基因成功地导入西瓜植株,并在后代中稳定遗传。经温室及大田接种鉴定,T3代转基因西瓜抗病毒性达中抗水平,为抗病毒无籽西瓜新品种的培育提供了可能性。     

Suppression of influenza virus infection by the orf virus isolated in Taiwan

Orf virus (ORFV), a member of parapoxvirus, is an enveloped virus with genome of double-stranded DNA. ORFV causes contagious pustular dermatitis or contagious ecthyma in sheep and goats worldwide. In general, detection of viral DNA and observing ORFV virion in tissues of afflicted animals are two methods commonly used for diagnosis of orf infection; however, isolation of the ORFV in cell culture using virus-containing tissue as inoculum is known to be difficult. In this work, the ORFV (Hoping strain) isolated in central Taiwan was successfully grown in cell culture. We further examined the biochemical characteristic of our isolate, including viral genotyping, viral mRNA and protein expression. By electron microscopy, one unique form of viral particle from ORFV infected cellular lysate was demonstrated in the negative-stained field. Moreover, immunomodulating and anti-influenza virus properties of this ORFV were investigated. ORFV stimulated human monocytes (THP-1) secreting proinflammatory cytokines IL-8 and TNF-α. And, pre-treatment of ORFV-infected cell medium prevents A549 cells from subsequent type A influenza virus (IAV) infection. Similarly, mice infected with ORFV via both intramuscular and subcutaneous routes at two days prior to IAV infection significantly decreased the replication of IAV. In summary, the results of a current study indicated our Hoping strain harbors the immune modulator property; with such a bio-adjuvanticity, we further proved that pre-exposure of ORFV protects animals from subsequent IAV infection.     

Allozyme variation in riverine and lacustrine populations of Macrobrachium nipponense (de Haan)

Abstract. Allozyme variation at 32 protein genetic loci was studied in four populations of Macrobrachium nipponense (de Haan) from two contrasting habitats, wholly freshwater lacustrine sites and brackish water riverine areas from different parts of Asia (Hong Kong, Canton, Wuhan, Japan). The average values of observed heterozygosity were 7·45% for lacustrine and 12·30% for riverine sites, the percentage of polymorphic loci (0·99) was 32·5%. The freshwater/lacustrine populations had lower estimates of genetic variability than the river/brackish water populations. The average genetic similarity and genetic distance (Nei's) were 0·92 and 0·084 respectively. The results were compared with those of the only other study on this species. The implications of these results for this species are discussed.     

Clinical investigations of halothane and isoflurane for induction and maintenance of foal anesthesia

Fifty-eight foals were divided into two groups for study of aspects of the clinical anesthetic management of foals and to characterize effects of halothane (n = 30) and isoflurane (n = 28) in foals. There were no significant differences (P greater than 0.05) in the demographics of the two groups. Results of hemograms and biochemical analysis of venous blood samples before and after anesthesia were either not influenced or only mildly (clinically unimportant) affected by either agent. Like adult horses, foals have an increased PaCO2 when anesthetized with inhaled anesthetics. We could detect no difference in the magnitude of increase in PaCO2 with either anesthetic. Anesthetic induction and recovery was most rapid with isoflurane. The quality of induction and recovery was similarly acceptable with either agent. Heart rate during isoflurane was not significantly different from conscious conditions but during halothane, heart rate was significantly less than control except at 91-120 min when statistical significance was not detected. These results support the clinical impression that foals can be safely and reliably anesthetized with either agent.     

土壤中含钾测定方法(J.L.Smith法)的改进

以碳酸鈣、氯化銨混合体,来熔化土壤中鉀矿物的方法^{[Lawrence Smith(史密司)法]}是分析化学上通用了最久的方法之一^[1]。这个方法,显然具有分解作用比較彻底的优点,而土壤及岩石中某些原生鉀矿物又为一般酸液所不能溶解。分析化学家在最近20-30年以来,企图用各种混合酸液(特别是氟氫酸——过氯酸——硫酸)来代替史密司的冗长熔化步驟^[2],但是在对待某些富有Al、Ti、Ba等合鉀矿物的土壤时,显然沒有达到完全分解的目的。