Reduced insulin-like growth factor-I after acute feed restriction in lactating dairy cows is independent of changes in growth hormone receptor 1A mRNA

Growth hormone receptor (GHR) and insulin-like growth factor-I (IGF-I) mRNA decrease in the liver of dairy cows at parturition. Epinephrine is released and feed intake is decreased at the same time. The objective of this study was to determine whether feed restriction and (or) administration of epinephrine could recapitulate the changes in the hepatic GHR 1A and IGF-I mRNA that occur at parturition. Eight lactating cows were randomly assigned to one of two rations (ad libitum or restricted). The cows assigned to the restricted ration were fed 75, 60, 60, and 25% of feed consumed by the ad libitum cows on successive days to mimic the changes in feed intake around parturition. Liver samples were collected by needle biopsy before and after feed restriction. Cows received either 0.02 mg/kg of epinephrine or saline approximately 24 h before the second liver biopsy so that a 2 x 2 factorial arrangement of treatments was created. Feed restriction increased plasma nonesterified fatty acids and liver triglyceride percentages and decreased plasma IGF-I concentrations. The decrease in plasma IGF-I after feed restriction was associated with a decrease in IGF-I mRNA in feed-restricted cows. The amount of GHR 1A mRNA did not change after feed restriction. Epinephrine treatment did not affect the amount of GHR 1A or IGF-I mRNA. We conclude that the decrease in feed intake at parturition may be partially responsible for the decrease in IGF-I but may not cause the decrease in GHR 1A.     

"635"水利枢纽发电引水洞竖井混凝土防腐处理

针对“635”水利枢纽发电引水洞竖井混凝土腐蚀破坏的原因,通过室内试验选定了防腐材料和竖井防腐混凝土。设计了竖井衬砌混凝土的防腐处理方案,使竖井混凝土的防腐措施有效、经济、安全可靠。     

提高肉牛对精粗饲料利用效果的研究

利用5-7月龄断奶公犊和一周岁杂交肉牛，粗饲料以青贮玉米秸、酒槽为主，添加不同比例的全价精料。观察其饲喂及日增重效果。并与当地饲养方式进行同期比较。     

地震作用对高进水塔闸室侧墙的影响分析

利用 8～ 2 1节点块体单元离散了小浪底 3号进水塔 ,对 5种工况进行了静动力分析 ,通过对闸室侧墙的应力状态计算 ,得出了一些可作为设计依据的有益结论 .     

试论河床辐射井取水技术的新进展

本文在提出辐射管内涵问题的前提下,对影响辐射管进水效果的滤管有效孔隙率与进水孔布置方式在试验研究与理论分析方面所取得的新进展作了较全面的论述,接着通过工程实例剖析了新型无砂混凝土透水水平滤管与不排泥沙直接顶进水平滤管的应用效果及其技术经济优点与特色。最后针对河床辐射并长期运行后并周河床的板结淤塞状况,还介绍了两种近些年来出现的处理新技术。     

Short communication: Effects of subacute ruminal acidosis on free-choice intake of sodium bicarbonate in lactating dairy cows

The effect of inducing subacute ruminal acidosis (SARA) on the free-choice intake of sodium bicarbonate (SB) was investigated in four midlactation Holstein cows in a switchover experiment with four 1-wk periods. The SARA was induced by replacing 25% of the ad libitum intake of total mixed ration (TMR) with pellets containing 50% ground wheat and 50% ground barley and restricting access to TMR from 0700 to 1700 h. Control consisted of feeding TMR ad libitum. Powdered SB was provided for ad libitum consumption. Rumen pH was measured continuously using indwelling pH probes. Induction of SARA reduced (P < 0.05) the average daily rumen pH from 6.08 to 5.87, increased (P < 0.05) the average duration of rumen pH below 6 from 547 min x d(-1) to 916 min x d(-1), and increased (P < 0.05) the average duration of rumen pH below 5.6 from 132 min x d(-1) to 397 min x d(-1) (P < 0.05) but did not significantly affect SB intake. Average intake of SB was 26.8 g x d(-1) during SARA and 34.5 g x d(-1) during control. These low SB intakes must not have substantially affected rumen pH. Sodium bicarbonate intake differed significantly (P < 0.05) between cows. These data indicate that cows did not select SB in order to attenuate SARA.     

竖井式隧洞进水口衬砌的应用研究

竖井式进水口的钢筋砼衬砌可以通过打排水孔使外水内排,从而达到设计优化的目的。     

汽车空气滤清器声学性能数值计算及分析

发动机进气系统设计除了满足进气和空气滤清要求外，通常还要求能够有效地降低进气噪声。设计消声效果良好的空气滤清器是控制发动机进气噪声的有效措施之一。由于一维平面波理论只适于低频分析，为了扩大分析的频率范围，采用了三维有限元数值方法分析空气滤清器的声学特性。同时，空气滤清器中的滤纸大多是纤维材料，可以作为吸声材料来处理，所以在考虑滤纸的情况下分析空气滤清器的消声性能，其中以纤维吸声材料的经验公式来模拟滤纸的声学特性。通过比较不带滤纸和带有滤纸的空气滤清器的声学性能结果表明，滤纸的考虑与否对空滤器的中高频消声性能有很大影响。     

Food reinforcement, the dopamine D? receptor genotype, and energy intake in obese and nonobese humans.

[Correction Notice: An erratum for this article was reported in Vol 122(1) of Behavioral Neuroscience (see record 2008-01943-025). In the original article, the n values (and corresponding percentages) for the number of people with the A1/A1 & A1/A2 and A2/A2 genotypes were reversed in Table 2. The corrected table appears in the erratum, with the revised numbers appearing in bold font.] The authors measured food reinforcement, polymorphisms of the dopamine D? receptor (DRD?) and dopamine transporter (DAT1) genes, and laboratory energy intake in 29 obese and 45 nonobese humans 18-40 years old. Food reinforcement was greater in obese than in nonobese individuals, especially in obese individuals with the TaqI A1 allele. Energy intake was greater for individuals high in food reinforcement and greatest in those high in food reinforcement with the TaqI A1 allele. No effect of the DAT1 genotype was observed. These data show that individual differences in food reinforcement may be important for obesity and that the DRD? genotype may interact with food reinforcement to influence energy intake. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Food reinforcement and eating: A multilevel analysis.

Eating represents a choice among many alternative behaviors. The purpose of this review is to provide an overview of how food reinforcement and behavioral choice theory are related to eating and to show how this theoretical approach may help organize research on eating from molecular genetics through treatment and prevention of obesity. Special emphasis is placed on how food reinforcement and behavioral choice theory are relevant to understanding excess energy intake and obesity and how they provide a framework for examining factors that may influence eating and are outside of those that may regulate energy homeostasis. Methods to measure food reinforcement are reviewed, along with factors that influence the reinforcing value of eating. Contributions of neuroscience and genetics to the study of food reinforcement are illustrated by using the example of dopamine. Implications of food reinforcement for obesity and positive energy balance are explored, with suggestions for novel approaches to obesity treatment based on the synthesis of behavioral and pharmacological approaches to food reinforcement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)