Selective recovery from retrograde amnesia produced by hippocampal spreading depression

Injections of potassium chloride into the hippocampus after learning produce temporary disruption of neural activity and retrograde amnesia. Recovery from the amnesia is selective-rats recover from amnesia of events that occurred24 hours before injection but do not recover from amnesia of events that occurred 10 seconds before injection.     

Long temporal gradient of retrograde amnesia for a well-discriminated stimulus

This experiment tested the general validity of recent findings that retrograde amnesia can be produced by electroconvulsive shock only if the shock is administered within 10 to 30 seconds after the learning trial. Precautions were taken to avoid confusion of other shock effects with retrograde amnesia. A temporal gradient of elec- troconvulsive shock-produced retrograde amnesia, extending up to at least 1 hour, for a well-discriminated stimulus, was demonstrated in mice in a one-trial learning passive avoidance situation.     

Ether-induced retrograde amnesia for one-trial conditioning in mice

Mice were tested in a situation permitting them to step readily from a small, restrictive platform to a larger one. Conditioned avoidance was established by a single training trial when animals received a shock by stepping from one platform to another. At various intervals after the single punishing shock, subjects were anesthetized with diethyl ether. Interference with retention, tested 1 day later, was shown for intervals up to 24 minutes, at which time ether no longer appeared to influence the subsequent response.     

Permanence of retrograde amnesia produced by electroconvulsive shock

The permanence of retrograde amnesia produced for a single training trial by a single electroconvulsive shock was studied. No recovery from amnesia was found with either single or repeated retention tests. Amnesic effects were found to be permanent with retention intervals as long as 1 month.     

Electroshock effects on brain protein synthesis: relation to brain seizures and retrograde amnesia

The effects of electroshock on brain seizure activity and brain protein synthesis were studied in male mice. A significant but short-lasting inhibition of brain protein synthesis and an increase in the amount of free leucine were produced by electroshock at intensities above the brain seizure threshold. Electroshock at intensities below the brain seizure threshold did not affect brain protein synthesis.     

Recovery of memory after amnesia induced by electroconvulsive shock

Electroconvulsive shock given to rats immediately after one-trial avoidance learning produced a significant amnesic effect 24 hours later; this amnesia had largely disappeared in further retention tests 48 and 72 hours after treatment. This result puts in question a basic assumption implicit in most memory consolidation studies that such amnesic effects will be permanent.     

Retrograde amnesia: effects of handling and microwave radiation

Rats that were irradiated with microwaves immediately after the training trial in a one-trial shock-avoidance learning task retained the conditioned avoidance response 24 hours later. However, rats that were handled a few minutes each day for 3 days before the experiment did not retain the response, although they were capable of learning in a later test.     

Retrograde amnesia gradients: effects of direct cortical stimulation

Electrical stimulation was delivered bilaterally to either the anterior or posterior cortex in rats from 0.1 second to 4 hours after a single training trial on an inhibitory avoidance task. As indicated by a retention test given 24 hours later, the length of the retrograde amnesia gradients ranged from 5 seconds to 240 minutes, depending on the brain region stimulated and the intensity of the stimulating current. The stimulation intensity that was threshold for amnesia varied directly with the length of the interval between training and treatment.     

Oblique impact: a process for obtaining meteorite samples from other planets

Cratering flow calculations for a series of oblique to normal (10 degrees to 90 degrees ) impacts of silicate projectiles onto a silicate halfspace were carried out to determine whether or not the gas produced upon shock-vaporizing both projectile and target material would form a downstream jet that could entrain and propel SNC meteorites from the Martian surface. The difficult constraints that the impact origin hypothesis for SNC meteorites has to satisfy are that these meteorites are lightly to moderately shocked and yet have been accelerated to speeds in excess of the Martian escape velocity (more than 5 kilometers per second). Two-dimensional finite difference calculations were performed that show that at highly probable impact velocities (7.5 kilometers per second), vapor plume jets are produced at oblique impact angles of 25 degrees to 60 degrees and have speeds as great as 20 kilometers per second. These plumes flow nearly parallel to the planetary surface. It is shown that upon impact of projectiles having radii of 0.1 to 1 kilometer, the resulting vapor jets have densities of 0.1 to 1 gram per cubic centimeter. These jets can entrain Martian surface rocks and accelerate them to velocities greater than 5 kilometers per second. This mechanism may launch SNC meteorites to earth.     

西气东输站场放空天然气回收需求与工艺

天然气长输管道增压站和分输站放空主要包括紧急抢修放空和计划性放空,前者具有随机性,单次放空量大,不具备回收的技术条件,后者主要指分离器排污放空和压缩机定期检修放空,具有较强的计划性和一定的规律性,具有良好的回收基础条件和回收价值。西气东输管道站场压缩机检修和分离器排污两项放空量之和占总放空量的50%以上,对放空天然气进行回收是可行和必要的。为此,设计了一套以CNG压缩机为核心的站场放空天然气回收工艺系统,可对站场因设备维修、排污等产生的放空天然气进行回收并重新注入上游管道、下游管道或分输管道,达到节能减排的目的。     

Memory: modification of anisomycin-induced amnesia by stimulants and depressants

Mice were trained in a passive (foot shock)avoidance task. When administered after training, the stimulants caffeine or nicotine blocked amnesia for the task that had been produced by injections of the protein synthesis inhibitor anisomycin given prior to training. With foot shock at a higher intensity, anisomycin did not produce amnesia by itself, but the administration of the depressants chloral hydrate or sodium phenobarbital after training did cause amnesia. Stimulants and depressants did not have an appreciable influence on the overall degree of protein synthesis inhibition produced by anisomycin. The results support the hypothesis that arousal after training is an important factor in the conversion of short-term to long-term memory.     

Science centers: a potential for learning

The past decade has witnessed a proliferation of science-technology centers, or public places for informal learning about science and technology. Science centers are the only institutions that can provide the general public with participatory exhibits and experiences, together with an accurate scientific interpretation of the materials that are involved. The dramatic rise in attendance and the enthusiasm of repeat visitors to science centers reflect a strong public demand for exhibits designed to help the visitor develop a better understanding of the contemporary scientific issues of society.     

鱿鱼皮胶原蛋白的测定与回收

为回收鱿鱼皮中胶原蛋白等有益成分，首先对胶原蛋白的定量方法进行了考察，确立了适宜于鱿鱼皮中胶原蛋白含量测定（以羟脯氨酸汁）的方法。结果表明，在测定鱿鱼皮中胶原蛋白的含量时，宜先将鱿鱼皮进行脱脂处理，然后再直接水解测定羟脯氨酸。就水解条件而言，可分别采用120℃水解12h或130℃水解6h代替ISO-3496E方法中的105℃水解16h，以缩短水解时间，其次，采用酶法促溶和热水提取的方法对鱿鱼皮中胶原蛋白进行回收利用，以胶原蛋白回收率为依据，提出胃蛋白酶5℃酶解72h和100℃水提6h分别为酶法提取和热水提取的方法对鱿鱼皮中胶原蛋白进行回收利用，以胶原蛋白回收率为依据，得出胃蛋白酶5℃酶解72h和100℃水提6h分别为酶法提取和热水提取的最佳条件，将提取液调配后进行感官鉴定，统计结果表明，胃蛋白酶提取液显著优于100℃水提液。对胃蛋白酶酶提温度的选择说明，胃蛋白酶促溶温度宜控制在15℃以下，以得到较高的胶原蛋白回收率和较好的酶提液色泽。     

Mathematics and science learning: a new conception

Findings in cognitive science suggest new approaches to teaching in science and mathematics.     

板条出材率的研究

对原木加工中常出现的三角板条再加工与利用作了初步探索。结果表明,一般原木的板条锯材出材率为3.23—3.42％,带25％钝棱的板条锯材出材率可达4.31—4.56％。     

棉花遭受涝渍胁迫后的快速恢复技术

[目的]研究棉花苗期遭受涝渍胁迫后,采用不同的恢复技术对棉花形态、生理和产量及其构成因子的影响,为遭受涝渍胁迫后的棉花快速恢复提供理论参考。[方法]采用盆栽方法,以湘杂棉8号F1、中棉所63F1为试验材料,淹水15 d排除渍水后进行恢复,设置双对照,共13个处理。研究采用恢复技术后棉花形态生长、SPAD、产量、棉铃等特征变化。[结果]涝渍胁迫后采用恢复技术能加快棉花株高及叶片增长。喷施天丰素、尿素及磷酸二氢钾等技术能提高主茎功能叶叶绿素含量。喷施萘乙酸、赤霉素、乙烯利、尿素加磷酸二氢钾,土壤穴施复合肥,土壤穴施复合肥配合喷施尿素加磷酸二氢钾等恢复技术均能提高单株地上部分干物质积累量及总干物质积累量,其中总干物质积累量提高最大的技术为土壤穴施,分别比胁迫不采用恢复技术处理总干物质积累量提高45.2%、70.4%;总干物质积累量恢复到不受涝渍胁迫处理的54.1%、58.2%。对籽棉产量分析,植株喷施尿素加磷酸二氢钾、土壤穴施氮磷钾复合肥2项技术,与涝渍胁迫不采用恢复技术对照比较均达极显著差异,其中植株喷施尿素加磷酸二氢钾技术比涝渍胁迫不采用恢复技术对照提高94.9%、144.5%,恢复到未受涝渍胁迫对照的71.3%、73.6%。[结论]通过试验数据分析,棉花苗期遭受涝渍胁迫后,喷施尿素加磷酸二氢钾、土壤穴施复合肥均能快速恢复棉花生长。