增强微流控芯片化学发光检测灵敏度的研究

为增强微流控芯片化学发光检测的灵敏度,扩大该方法的应用领域,利用金属离子催化鲁米诺-过氧化氢反应,通过比较几种结构不同的微流控芯片,对影响检测发光信号灵敏度的因素,如试剂浓度、流速和微通道的尺度等作了详细地讨论。提出了具有双螺旋形结构芯片的微流动注射系统,大大增强了化学发光检测的灵敏度。在最佳实验条件下,铬离子(Cr3+)浓度在5.0×10-9~2.0×10-6mol/L范围内与其体系的发光信号强度具有一定的线性关系,对浓度为6.0×10-8mol/L的铬连续11次进样,相对标准偏差为1.59%,其检出限为1.50×10-9mol/L。该体系可以成功地用于天然湖水和自来水中金属铬的分析和检测。     

Chromium propionate improves performance and carcass traits in broilers

There is evidence to suggest that poultry may have a dietary requirement for metabolically available chromium (Cr) that exceeds the amount provided through wheat soybean meal diets. The objective of the present study was to investigate the effects of dietary supplemental organic Cr from Cr propionate at different dose levels (control = 0 μg/kg, T1 = 200 μg/kg, T2 = 400 μg/kg) on the growth performance, carcass traits, and meat quality of broilers. Weight gain and feed intake of each treatment were recorded at the start and after 14, 28 and 35 d, and feed conversion ratios (FCR) were calculated accordingly. At 35 d of age, birds were randomly selected and euthanized for carcass evaluation. Results of the first trial indicate that both Cr propionate treatments increased final body weight (P < 0.05), feed efficiency (P < 0.05) and body weight gain (P < 0.0001). Furthermore, Cr propionate supplementation improved (P < 0.0001) all carcass characteristics. Interestingly, with increased Cr dosage, carcass yield, dressing percentage and breast meat yield increased linearly (P < 0.0001). The second study reveals that the feed intake in the control group was significantly higher compared to both Cr propionate supplemented groups (T1 & T2). Furthermore, the Cr propionate supplemented T2 group displayed a significantly lower FCR than the control and T1 group (P = 0.027). Finally, Cr propionate supplementation increased the dressing percentage compared to control birds (P < 0.0001). In the third experiment, Cr propionate supplementation (T1 & T2) increased final body weight and decreased FCR compared with the control treatment. These effects were highly significant (P < 0.0001) throughout all feeding phases of the trial. Cr propionate supplementation also increased (P < 0.0001) carcass yield, dressing percentage, breast meat yield, leg and thigh weights compared with the control treatment. In conclusion, growth performance, feed conversion, carcass yield, breast and leg meats of broiler birds can be significantly improved by dietary inclusion of Cr propionate. Cr propionate can be supplemented to broiler birds from 1 d old of age at a level that provides 200 or 400 μg/kg organic Cr and can increase the efficiency of broiler production.     

铬鞣皮渣脱铬及其在肉鸡饲养中的应用

本研究采用了物理、化学方法对铬鞣皮渣进行不同处理,根据脱铬效果、蛋白回收率及工艺流程的实用性筛选出最理想脱铬方法。然后,用脱铬皮渣溶解滤液和骨粉以1:2(脱铬皮渣:骨粉;干物质计)制成含蛋白42.6％的脱铬皮渣骨粉,饲喂罗曼肉鸡。通过饲养、代谢试验研究了铬鞣皮渣和脱铬皮渣骨粉的营养与经济价值。结果表明:用5％Ca(OH)_2对铬鞣皮渣进行30分钟煮沸处理是理想脱铬方法,脱铬率达99.99％,蛋白回收率达74.95％。脱铬皮渣骨粉可代替肉鸡饲粮中的全部鱼粉(6％),以代替鱼粉量的60％效果最好,此时饲料成本低,鸡增重快,经济效益也高。铬鞣皮渣不经脱铬处理直接饲喂肉鸡,其在饲粮中含量为3％(饲粮此时铬含量为230.81ppm)时,即影响鸡的生长发育,不仅增重慢,且有5.1％的鸡出现铬中毒,随着饲粮中铬鞣皮渣的增多,鸡所受危害加大。     

Sorption Characteristics of Chromium and Its Phytotoxic Effect with or without City Compost on Maize and Spinach in a Vertisol of Central India

Abstract

Phytotoxicity, due to chromium [Cr (VI)] additions from low to very high levels in a swell–shrink clayey soil (Haplustert), in maize and spinach was studied in a pot culture experiment. Six levels of Cr (VI) (0, 5, 10, 25, 50, and 75 mg kg^?1 soil) for maize and five levels for spinach (0, 2, 5, 10, and 25 mg kg^?1 soil) were applied singly and in combination with two doses (0 and 20 t ha^?1) of city compost. At levels of more than 75 mg Cr (VI) kg^?1 soil for maize there was virtually no growth after germination, whereas 25 mg Cr (VI) kg^?1 soil hindered the germination of spinach crop. Initial symptoms of Cr (VI) toxicity appeared as severe wilting of the tops of treated plants. Maize plants suffering from severe Cr (VI) toxicity had smaller roots and narrow brownish red leaves covered with small necrotic spots. In spinach, severe chlorosis was observed in leaves. Higher levels of Cr (VI) inhibited the growth and dry‐matter yield of the crops. However, application of city compost alleviated the toxic effect of Cr (VI). The concentration of Cr (VI) in plant parts increased when Cr (VI) was applied singly but decreased considerably when used in combination with city compost. There was evidence of an antagonistic effect of Cr (VI) on other heavy‐metal (Mn, Cu, Zn, and Fe) concentrations in plant tops. Thus, when Cr (VI) concentration increases, the concentration of other beneficial metals decreases. Chromium (VI) concentration in maize roots ranged from traces (control) to 30 mg kg^?1and were directly related to soil Cr (VI) concentration. At 25 mg Cr (VI) kg^?1 soil, yield of maize was reduced to 41% of control plants, whereas in spinach, 10 mg Cr (VI) kg^?1 soil caused a 33% yield reduction. Experimental results revealed that the maize top (cereal) is less effective in accumulating Cr (VI) than spinach (leafy vegetables). Laboratory studies were also conducted to know Cr (VI) sorption capacity of a swell–shrink clayey soil with and without city compost, and it was found that Cr (VI) sorption reaction was endothermic and spontaneous in nature.     

Effect of Chromium and Lead on Yield,Chemical Composition of Essential Oil,and Accumulation of Heavy Metals of Mint Species

A pot culture experiment was conducted to investigate the effect of increasing levels (30.0 and 60.0 mg kg^?1 soil) of chromium and lead on the yield, chemical composition of essential oil, and phytoaccumulation of heavy metals of three mint species (Mentha arvensis, M. piperita, and M. citrata). The fresh herbage yield of M. arvensis was not significantly affected by the application of chromium and lead, but its essential oil yield was significantly decreased by the application of chromium and lead as compared to the control. The fresh herbage, root yield, and essential oil yield of M. piperita were significantly increased and those of M. citrata were decreased by the increase in the levels of chromium and lead applications. The levels of α-pinene, β-pinene, sabinene, β-myrcene, limonene, menthone, and isomenthone in M. arvensis and M. piperita oil and of sabinene, pinene, and linalyl acetate in M. citrata oil were considerably affected by the application of chromium and lead to soils as compared to control plants. The concentrations of chromium in shoots and roots of mint species significantly increased as the levels of chromium in soil increased. The increases in the levels of lead in soil enhanced the concentrations of lead in the shoots and roots of mint species as compared to the control. The accumulations of chromium and lead were greater in the roots than in the shoots in all the three species of mint. Mentha piperita was found to be the most suitable crop for cultivation in the chromium- and lead-contaminated soils, followed by M. arvensis and M. citrata.     

饲粮铬对热应激产蛋鸡产蛋性能、蛋品质、血清生化特性及免疫功能的影响

用 49周龄北京红商品产蛋鸡 12 0只 ,按 2× 3因子安排的完全随机设计随机分为 5组 ,分别饲喂不添加铬的玉米 豆粕型对照组基础饲粮和以三氯化铬或吡啶羧酸铬形式添加 2 0、10 0mg/kg铬的饲粮 ,在热应激条件下(9:0 0～ 17:0 0维持 36± 2℃ ,其余时间 2 8± 2℃ )饲养 30d ,研究铬源及铬水平对热应激产蛋鸡产蛋性能、蛋品质、血清生化特性及免疫功能的影响。铬源对蛋壳厚度、蛋壳百分率、血清甘油三酯及全血T淋巴细胞转化率有明显影响 (P <0 0 4) ,对所观测的其余指标无显著影响 (P >0 10 )。铬水平对采食量、料 /蛋比、蛋壳厚度、蛋壳百分率、蛋黄颜色、血清甘油三酯含量、碱性磷酸酶活性 (AKP)和全血T淋巴细胞转化率有明显影响 (P <0 10 ) ,但对所观测的其余指标无明显影响 (P >0 12 )。其中添加 2 0mg/kg铬组采食量高于对照组 (P <0 0 4) ,添加 10 0mg/kg铬组采食量与对照组和添加 2 0mg/kg铬组间均无明显差异 (P >0 14) ;除第 2周添加 10 0mg/kg铬组蛋黄颜色未明显高于对照外 (P >0 76 ) ,其它各周添加 2 0和 10 0mg/kg铬组蛋黄颜色均显著高于对照组 (P <0 0 9) ;添加 2 0和 10 0mg/kg铬组 ,料 /蛋比高于对照组 (P <0 0 6 ) ,血清甘油三酯含量低于对照组 (P <0 0 7) ,血清AKP活     

重金属离子铬(Ⅵ)对螺旋藻生长的影响

研究了不同质量浓度的重金属离子铬(Ⅵ)对螺旋藻生长及其藻胆蛋白含量的影响。结果表明:铬(Ⅵ)在一定浓度范围内(<10 mg/L)能够提高螺旋藻藻胆蛋白的含量,对螺旋藻的生长具有促进作用。当铬(Ⅵ)浓度过高(>10 mg/L)时,螺旋藻藻胆蛋白含量下降,螺旋藻的生长受到较强抑制。     

铬污染土壤治理组合技术应用

以某铁合金厂堆存铬渣污染土壤为研究对象,根据场地的实际情况采用湿法解毒技术、固化稳定化技术及资源化烧砖组合技术,对铬渣污染土壤进行了治理,取得了较好的效果。     

Systemic,Renal, and Colonic Effects of Intravenous and Enteral Rehydration in Horses

Background

Intravenous (IV) and intragastric (IG) administration of fluid therapy are commonly used in equine practice, but there are limited data on the systemic, renal, and enteric effects.

Hypothesis

IV fluid administration will increase intestinal and fecal hydration in a rate‐dependent manner after hypertonic dehydration, but will be associated with significant urinary water and electrolyte loss. Equivalent volumes of IG plain water will result in comparatively greater intestinal hydration with less renal loss.

Animals

Six Thoroughbred geldings.

Methods

Experimental study. 6 by 6 Latin square design investigating constant rate IV administration at 50, 100, and 150 mL/kg/d over 24 hours in horses dehydrated by water deprivation. Equivalent volumes of IG plain water were administered by 4 bolus doses over 24 hours.

Results

Water deprivation resulted in a significant decrease in the percentage of fecal water, and increases in serum and urine osmolality. IV fluids administered at 100 and 150 mL/kg/d restored fecal hydration, but increasing the rate from 100 to 150 mL/kg/d did not confer any additional intestinal benefit, but did result in significantly greater urine production and sodium loss. Equivalent 24‐hour volumes of plain water resulted in greater intestinal water and less urine output.

Conclusions and Clinical Importance

IV polyionic isotonic fluids can be used to hydrate intestinal contents in situations where enteral fluids are impractical. IV fluids administered at three times maintenance are no more efficacious and might be associated with adverse physiological findings after withdrawal. Bolus dosing of IG water can be used to restore intestinal water with minimal adverse effects.     

壳聚糖对铬胁迫下豌豆种子萌发的影响

以豌豆(Pisum sativum L.)为材料,研究了铬对水培豌豆的胁迫作用及壳聚糖(chitosan,CTS)对铬胁迫的缓解效应。结果表明:0～200 mg.L-1铬胁迫浓度范围内,随铬胁迫浓度的增加,豌豆种子的发芽率、发芽指数和活力指数等下降,下胚轴丙二醛含量和相对电导率增加;显著抑制豌豆种子萌发的铬胁迫浓度为100mg.L-1,极显著抑制豌豆种子萌发的铬胁迫浓度为200 mg.L-1。0.5%壳聚糖可缓解铬对豌豆种子萌发的毒性。