Use of the nitrate‐specific ion electrode for the determination of nitrate nitrogen in surface and ground water

Abstract

The usefulness of the nitrate‐specific ion electrode (NE) for the determination of nitrate nitrogen (NO3‐N) in surface and ground water was determined. The NE method had several advantages that made it superior to the phenoldisulfonic acid (PDS) method in our environmental quality studies. Samples could be analyzed quickly and with a minimum of sample preparation. Sample coloration and soluble salts did not interfere with the performance of the electrode. Range of detection without dilution was much wider than by the PDS method. Also, the values obtained by the NE method, although slightly greater than those obtained by the PDS method, were satisfactory.     

New technique of sex preselection for increasing female ratio in boar sperm model

In this study, we tried to optimize the porcine semen extender conditions to maximize the differences between live X chromosome-bearing (X) spermatozoa and to Y chromosome-bearing (Y) spermatozoa without a decline in the fertility rate at different pH conditions during storage. We observed the viability of X and Y boar spermatozoa in acidic (pH 6.2), original (pH 7.2), and alkaline condition (pH 8.2) for 5 days to investigate the effect of storage conditions on the X to Y spermatozoa ratio. The functional parameters of spermatozoa were also examined to evaluate sperm quality. Sperm motility was preserved at pH 7.2 and pH 6.2 for 3 days, while sperm motility at pH 8.2 decreased significantly after 2 days. Non-capacitated spermatozoa increased while capacitated spermatozoa decreased during storage. Sperm viability decreased significantly duration-dependent under all pH conditions, but there was no significant difference during storage at pH 6.2 and 7.2. The X: Y ratio of live spermatozoa in acidic condition was maximized (1.2:1) without affecting the sperm function and fertility-related protein expression after 2 days compared to original conditions. Moreover, insemination of sows using acidic extender increased the number of female pups on days 1 and 2 of preservation. These results indicate that the production of female offspring may increase when acidic BTS is used for 2 days without affecting the success rate of AI. Above all, this method is simple and economical compared to other methods.     

Fatty acid profile as affected by fat depot and the sex category of Polish Holstein-Friesian × Limousin fattening cattle fed silage ad libitum

This study was designed to compare the fatty acid profiles of four types of fat depots from bulls, steers, and heifers. All animals were Polish Holstein-Friesian and Limousin crossbreds fattened semi-intensively—silage at libitum and concentrate in the amount corresponding to 30% of their net energy requirements. The fatty acid profile in intramuscular, intermuscular, and external and internal fat was determined. The intramuscular fat of bulls was most abundant in total PUFAs and n-6 PUFAs, and functional fatty acids C 18:2, C 20:4, and C 22:5 in comparison with steers and heifers. Regardless of sex category, intramuscular and external fat were characterized by higher levels of UFAs and a more desirable MUFA/SFA ratio than the remaining fat types. It should also be noted that external fat was more abundant in CLA than other fat types, and that the highest CLA content was found in bull fat, compared with the remaining sex categories of cattle.     

Effect of mixed rearing of barrows and gilts on backfat thickness and serum metabolite profiles of the Kagoshima-Kurobuta (Berkshire) pig

We investigated the effect of mixed rearing of barrows and gilts on the backfat thickness and the serum metabolite profiles of Kagoshima-Kurobuta (Berkshire) pigs. A total of 149 pigs with an average body weight of 35 kg were divided into the following groups: 100%, 90%, 70%, 50%, 30%, 10%, and 0% groups consisting of 10 barrows (1 pen), 9 barrows + 1 gilt (3 pens), 7 barrows + 3 gilts (2 pens), 5 barrows + 5 gilts (3 pens), 3 barrows + 7 gilts (2 pens), 1 barrow + 9 gilts (3 pens), and 9 gilts (1 pen), respectively. All pigs were raised to a shipping weight of 120 kg. Mixed rearing significantly reduced (p < 0.001) backfat thickness, and the optimum mixing ratio of barrows and gilts was 7:3 (the 70% group). Four types of circulating sex steroids were found in both the barrows and gilts in the 50% group but were not detected in barrows from the 100% group. These results indicated that mixed rearing of barrows and gilts was effective for reducing the backfat thickness of barrows, and induced sex steroid hormones may influence the backfat thickness of barrows in mixed-reared groups.     

HPLC测定宫衣净酊中葛根素含量

为了建立宫衣净酊中葛根素的高效液相色谱(HPLC)测定方法,应用色谱柱为安捷伦Eclipse XDB-C18(4.6mm×250mm,5μm),流动相为甲醇-水(25∶75),流速为1mL/min,检测波长为250nm,柱温为30℃。结果表明,在此色谱条件下,葛根素的线性范围为18.25μg/mL~584.00μg/mL(r=0.999 9,n=6),平均回收率为108.83%(RSD=1.03%)。说明本方法简便、准确、重现性好,可以作为宫衣净酊的质量控制方法。     

中华卵索线虫人工室内培养技术

为室内大量繁殖中华卵索线虫Ovomermis sinensis,采用个体由大到小的斜纹夜蛾Spodoptera litura、棉铃虫Helicoverpa armigera和黏虫Mythimna separata作为宿主,测定被中华卵索线虫寄生后3种宿主的体长和体重,研究宿主种类对中华卵索线虫有效率、雌雄比和体长的影响以及寄生强度对线虫雌雄比的影响。结果显示,被中华卵索线虫寄生后,斜纹夜蛾、棉铃虫和黏虫生长减缓。在相同感染比例下（除宿主与线虫比为1∶15外）,3种宿主的线虫有效率之间差异不显著。当寄生强度为5时,3种宿主体内脱出的中华卵索线虫均为雌线虫;当寄生强度从10增到40时,斜纹夜蛾、棉铃虫和黏虫所脱出的雌性比分别由100.0%、90.0%、83.9%降为0;相同寄生强度下,从斜纹夜蛾体内脱出的雌性比显著高于从棉铃虫与黏虫体内脱出的雌性比。斜纹夜蛾、棉铃虫和黏虫体内脱出雌线虫和雄线虫平均体长分别为14.8、13.8、12.8 cm和8.0、7.5和7.5 cm。当中华卵索线虫与宿主按照比例20∶1～25∶1侵染斜纹夜蛾、按照15∶1侵染棉铃虫和黏虫时,能获得线虫最适雌雄比（1∶1...     

光源、性别及光处理时间对草地贪夜蛾趋光行为的影响

为研发高效、精准的监测防控设备,利用八臂行为选择装置系统测定不同光源、性别和光处理时间下草地贪夜蛾Spodoptera frugiperda的趋光行为。结果显示,在紫外光（波长365 nm）、紫光（波长420～430 nm）、蓝光（波长465～475 nm）、绿光（波长525～535 nm）、黄光（波长585～595 nm）和红光（波长655～665 nm）6种波长光源下,草地贪夜蛾混合种群（雌雄成虫比为1∶1）对紫外光光源的趋光选择率最高,为25.61%,显著高于其他处理,其次为紫光和蓝光光源,趋光选择率分别为16.30%和8.82%,对红光的趋光选择率最低,为4.76%。在紫外光刺激下,草地贪夜蛾雌成虫的趋光选择率显著高于混合种群（雌雄成虫比为1∶1）,在红光刺激下,雄成虫的趋光选择率显著高于雌成虫。另外,在紫外光刺激下,光处理时间60 min草地贪夜蛾雌成虫的趋光选择率显著高于其他处理。表明光源与性别因素均影响草地贪夜蛾的趋光行为,光处理时间对草地贪夜蛾的趋光行为影响较小,且与光源及性别因素有关。     

三氯蔗糖在食品加工中的应用及测定方法的研究概况

介绍了三氯蔗糖的特性。阐述了三氯蔗糖在食品加工中的应用及测定方法的研究概况。     

DETERMINATION OF METALLIC IRON IN HIGH TITANIUM SLAG BY HEADSPACE GAS CHROMATNGRALHY

The following details are discussed in the present paper, after high titanium slag and H3PO4 is put in the closed system,the .reaction takes place under controlled temperature conditions, and the gas produced is collected. The two phases of gas liquid attain kinetic equilibrium, ihe gas above the liquid is used to make GC analysis with the aid of chromatographic column of 5A molecular sieve, TCD and N2 30ml/min. Satisfactory quantitative results can be achieved with simple instruments and uncomplicated operation technique.