Biomechanics of the motor act following destruction of the somatic feedback connections

By means of cyclography method developed in detail by N.A. Bernstein for disclosing the changes in the physical parameters of jumps it was shown that as compared with intact animals, the speed of movements of the distal parts of the fore and hind limbs significantly decreases in animals with electro-coagulated medial lemnisci. The swing of flexion-extension in the ulnar and knee joints likewise diminishes, and the trajectory of the centre of gravity movement changes significantly. In the course of jumping from one platform to another the operated animal experiences difficulties in changing movement phases. It is suggested that the system of medial lemnisci exercises the function of internal somatic backward connection, which is necessary for the succession of micromovements within the general program of the motor act.     

Intensity difference thresholds after lesions of the visual Wulst in pigeons.

Studied visual intensity difference thresholds before and after telencephalic lesions in 8 White Carneaux pigeons. Ss with visual Wulst lesions showed initial postoperative threshold elevations that represented losses of 19–49% of their preoperative sensory capacity. This initial loss was correlated with the extent of damage to 3 components of the visual Wulst: nucleus intercalatus hyperstriati accessorii, hyperstriatum intercalatus suprema, and hyperstriatum accessorium. The damage to hyperstriatum dorsale, another component of the visual Wulst, made no contribution to the initial deficit. The sensory capacity of all but 1 S improved as a result of postoperative retraining. (28 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Reversal learning in pigeons: Effects of selective lesions of the Wulst.

Evaluated the effects of bilateral lesions of individual laminae of the Wulst on reversal-learning performance in pigeons. After surgery, Ss were trained to perform a simultaneous color discrimination. Once successful discrimination was achieved, the positive and negative stimuli were reversed, and Ss were again trained to criterion. 20 reversals were carried out. A multiple regression analysis indicated that those components of the Wulst that were critical for increasing the numbers of errors on each reversal were the laminae that receive the thalamofugal visual projections (i.e., the nucleus intercalatus of the hyperstriatum accessorium and the hyperstriatum dorsale). Lesions in the other laminae of the Wulst (the hyperstriatum accessorium and the hyperstriatum intercalatus superior) had no effect on errors. There was no evidence of an increase in either perseverative errors or position habits in the Ss with lesions, suggesting that the reversal deficits were not likely to be due to perseveration, attentional impairment, or inappropriate processing of spatial information. The deficit may have been produced by excessive interference between learning in a given session and learning in previous sessions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-evaluative appraisals of coping capability and posttraumatic distress following motor vehicle accidents.

This study tested the importance of coping self-efficacy (CSE) perceptions and change in perceptions of CSE for recovery from motor vehicle accident (MVA) trauma. Data were collected 7 days following the accident (Time 1; n = 163), 1 month after the accident (Time 2; n = 91), and 3 months after the accident (Time 3; n = 70). Early changes in CSE (i.e., from Time 1 to Time 2) predicted posttraumatic distress at 3 months after MVA trauma, even after controlling for Time 1 or Time 2 posttraumatic distress and other trauma-related variables (i.e., accident responsibility, litigation involvement, and peritraumatic dissociation). Early changes in CSE perceptions, however, neither moderated nor mediated the effects of early posttraumatic distress (Time 1) on 3-month posttraumatic distress. Time 2 CSE levels, however, did mediate the relationship between acute posttraumatic distress (Time 1) and 3-month posttraumatic distress (Time 3). These findings highlight the importance of early interventions aimed at strengthening self-efficacy after MVA trauma. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Recovery of spatial alternation deficits following selective hippocampal destruction with kainic acid.

[Correction Notice: An erratum for this article was reported in Vol 101(5) of Behavioral Neuroscience (see record 2008-10704-001). In the aforementioned article, the degrees of freedom reported in the Results section are incorrect. In the sixth paragraph on page 281, the second sentence should read as follows: Results of the ANOVA indicated a significant effect for surgical treatments. F(2, 25)=25.44, p     

Supersensitivity of anterior pituitary dopamine receptors involved in the inhibition of prolactin secretion following destruction of the medial basal hypothalamus

The medial basal hypothalamus of ovariectomized rats was destroyed using a modified Halász knife. Large increases in prolactin secretion were observed 1 and 14 days following the lesions. Long- and short-term lesioned animals were anesthetized with chloral hydrate and treated with various doses of apomorphine (0.05, 0.2, 2, 5 mg/kg). Blood samples were obtained before and 10, 30 and 60 minutes after the injection. Both the 0.05 and 0.2 mg/kg doses caused significantly greater and longer-lasting inhibition of prolactin in long-term than in short-term lesioned animals. Since the MBH was totally destroyed this study suggests that anterior pituitary dopamine receptors involved in the inhibition of prolactin secretion become supersensitive in long-term lesioned rats.     

An epornitic of avian cholera in waterfowl and common crows in Phelps County, Nebraska, in the spring, 1975

In the spring of 1975, many species of waterfowl and common crows (Corvus brachyrhynchos) were found dead in Phelps County, Nebraska. About 25,000 water fowl and at least 3,000 crows died in the epornitic. Few waterfowl were seen dying, but the crows experienced a chronic illness during which they became debilitated and were lethargic and dyspneic. Gross and microscopic lesions in the waterfowl were typical for acute avian cholera. The crows had dark, firm areas within the lungs, loosely adhered yellow fibrous material in the pericardial sac and air sacs and, occasionally, liver abscesses. Microscopically, focal purulent pneumonia was present and a fibrinopurulent exudate overlaid a granulomatous reaction on the heart and lung surfaces. Isolation of Pasteurella multocida serotype 1 confirmed the diagnosis of acute and chronic avian cholera in the waterfowl and crows, respectively.     

Extrapolation of in vitro enzyme induction data to humans in vivo

Enzyme induction generally increases the rate and extent of xenobiotic metabolism in vitro, but physiological constraints can dampen these effects in vivo. Biotransformation kinetics determined in hepatocytes in vitro can be extrapolated to whole animals based on the hepatocellularity of the liver, since the initial velocity of an enzyme-catalyzed reaction is directly proportional to the total enzyme present in the cell. The biotransformation kinetics of various xenobiotics determined with isolated hepatocytes in vitro have been shown to accurately predict pharmacokinetics in whole animals. Analysis of the kinetic data, using physiologically based pharmacokinetics, allows extrapolation of xenobiotic biotransformation across dose routes and species in a biologically realistic context. Several fold variations were observed in the bioactivation of the hepatotoxicant furan by isolated human hepatocytes, due to induction of cytochrome P450 2E1. Extrapolation of these data to humans in vivo showed that furan bioactivation was limited by hepatic blood flow delivery of the substrate. One important consequence of hepatic blood flow limitation is that the amount of metabolite formed in the liver is unaffected by increases in Vmax due to enzyme induction. Therefore, interindividual variations in cytochrome P450 2E1 among human populations would not affect the bioactivation of many rapidly metabolized hazardous chemical air pollutants. The hepatic blood flow limitation of biotransformation is also observed after oral bolus dosing of rapidly metabolized compounds. More slowly metabolized xenobiotics, such as therapeutic agents, are only partially limited by hepatic blood flow and other processes.     

自控系统设计及工作性能分析

对工业自动化控制系统的设计工作过程与性能进行了介绍和分析 ,并阐述了对系统的基本要求。     

Morphology of immune destruction of the erythrocytes in fetuses and newborn infants

In the second half of pregnancy destruction of erythrocytes as a result of immunological aggresion in the fetus may occur in different manners: hemolysis in the vessel bed, fragmentation of erythrocytes, phagocytosis of intact erythrocytes and their fragments. Intravascular hemolysis occurs in immature fetuses. At that, the products of erythrocyte decomposition (hemosiderin and lipofuscin) are accumulated in the epithelial cells of the liver and the kidneys, the pancreas, the thyroid and the thymus. Fragmentation of erythrocytes (anuclear forms alone) occurs in the red splenic pulp and less in the vessels of the other organs. This process has been observed in fetuses after 7 months of gestation. Phagocytosis of erythrocytes and their fragments is done mainly by macrophages of the red splenic pulp as well as macrophages of the bone marrow, lymph nodes, and the Kupffer cells of the liver. Massive and long-term effect of iso (rhesus) antibody results in inhibition of the phagocytary activity of macrophages. In such cases, destruction of erythrocytes occurs in the vessel bed by lysis.     

The kinetics of platelet production and destruction in man

Platelets are derived from the cytoplasm of mature marrow megakaryocytes through cytoplasmic demarcation by invaginating plasma membrane and fragmentation of cytoplasmic protrusions into marrow sinusoids. Thereafter, platelets survive in the circulation for about 9 to 10 days. Platelet production is regulated to meet the demands for circulating platelets by means of humoral stimulation. Mean platelet volume, about 10 fl, remains constant over a wide range of survival times and production rates. In normal individuals platelets are produced at a rate of 35 X 10(9)/1/day (or 2.5 X 10(10) fl/kg body wt.) and reflect directly the marrow megakaryocyte cytoplasmic mass. Platelets have important roles in haemostasis, arterial thrombogenesis, wound healing and atherogenesis. Measurements of platelet survival are useful as an in vivo indicator of platelet participation in pathogenesis and pharmacological prevention of these processes. At present platelet survival is most reliably determined by in vitro radiochromium population labelling. 51Cr-platelet disappearance curves require objective unbiased analysis, preferably by non-linear gamma function least squares computer fitting procedures.     

Cigarette smoking and periodontal destruction in young adults

The relationship between cigarette smoking and periodontal destruction was assessed in young adults. Eighty-two regular dental attenders (21 current cigarette smokers, 61 non-smokers) aged between 20 and 33 years were examined. The smokers consumed on average 15.4 (+/- 7.3) cigarettes per day and had smoked for an average of 11.8 (+/- 7) years. Cigarette smokers had almost the same levels of plaque as non-smokers but had more proximal surfaces with subgingival calculus (P < 0.01) and which bled on probing (P < 0.05). Smokers had significantly more pockets > or = 4 mm (14.6 +/- 19.9) than non-smokers (5.8 +/- 7.9), P < 0.01. Only 2 (10%) of the smokers and 1 (2%) of the non-smokers had deep pocketing (> or = 6 mm). Smokers had significantly more sites (21.8 +/- 24.9) with periodontal attachment loss of > or = 2 mm than non-smokers (9.3 +/- 12.2), P < 0.01. Severe loss of periodontal attachment (> or = 6 mm) was present in 4 (19%) of smokers compared with 2 (3%) of non smokers. In total 4 (19%) of the smokers had "established periodontitis" compared with 1 (2%) of the non-smokers. The odds ratio for the presence of "established periodontitis" and smoking was 14.1 (confidence interval 1.5 to 132.9). It is concluded that cigarette smoking was a major environmental factor associated with accelerated periodontal destruction in this selected group of young adult regular dental attenders.     

The creation and destruction of value.

Science characteristically pursues generalizations thought to approximate eternal truths. Thus, a science of values would be expected to specify the natural laws that govern human values and their effects on action. However, research in psychology suggests that values often are contextually determined, sociohistorical phenomena that can be created or destroyed. Traditional approaches to a science of values would be likely to reify historically specific and context-dependent phenomena into timeless generalizations that may then take on a normative force, shaping social life and institutions. An illuminating and useful science of values must include a critical examination of history and culture. By making the historical contingency of values clear, such a science could encourage discussion of what values people ought to have and what social arrangements best contribute to the development of those values. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conglomeration of metallic power and destruction of conglomerates

Theoretical principles describing the formation and disintegration of conglomerates are developed and used to formulate a method for mixing nanodisperse, ultradisperse, and highly disperse powders, with simultaneous disintegration of conglomerates. The operation of the corresponding mixing equipment is described.     

Responses of pigeon (Columba livia) Wulst neurons during acquisition and reversal of a visual discrimination task.

The avian visual "Wulst" is a target of the ascending thalamofugal visual pathway. In pigeons (Columba livia), lesion damage to the Wulst has little effect on simple visual discriminations, but impairs performance on tasks such as reversal learning. We recorded the responses of single Wulst neurons as pigeons were trained on the acquisition and subsequent reversal of a visual discrimination. Of the 64 units recorded, 54 (84%) displayed a significant difference in firing rate between some component of the task and the intertrial interval that separated trials. More important, 14 units (22%) displayed a significant change in firing rate exclusively to the S+ and/or S- as learning progressed either during acquisition or reversal. The responses of these 14 neurons indicate that learning during initial acquisition was as likely to correlate with a change in firing rate as during reversal, and some neuronal responses could be characterized as representing reward properties together with visual stimulus features. As such, responses of pigeon Wulst neurons indicate a role in representing aspects of learning as much as the physical/perceptual properties of visual stimuli. (PsycINFO Database Record (c) 2010 APA, all rights reserved)