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1.
Experiments have been made on Al-4 wt pct Cu single crystals to determine the influence of stress, applied during aging, on precipitation. Without stress, θ platelets precipitate on all (100) planes. Transmission electron microscopy showed a marked effect of aging stress on the microstructure. A compressive stress of approximately 48 MPa (~ 7,000 psi) parallel to [001] favored precipitation on (010) and (100) and inhibited precipitation on (001). When a tensile stress of similar magnitude was applied parallel to [001], precipitation was favored on (001) and inhibited on (010) and (100). 相似文献
2.
Experiments have been made on Al-4 wt pct Cu single crystals to determine the influence of stress, applied during aging, on
precipitation. Without stress, θ platelets precipitate on all (100) planes. Transmission electron microscopy showed a marked
effect of aging stress on the microstructure. A compressive stress of approximately 48 MPa (∼ 7,000 psi) parallel to [001]
favored precipitation on (010) and (100) and inhibited precipitation on (001). When a tensile stress of similar magnitude
was applied parallel to [001], precipitation was favored on (001) and inhibited on (010) and (100). 相似文献
3.
J. W. Rudy and R. J. Sutherland (1989) suggested that the hippocampal formation (HF) is necessary for performance of configural tasks and that rats with kainic acid?+?colchicine (K–C) damage to the HF were impaired on the negative patterning problem (A+, B+, AB–). However, M. Gallagher and P. C. Holland (1992) found spared performance on a similar task (AC+, B+, AB–, C–) when ibotenic acid (IBO) was used. This study compared the effects of K–C and IBO-induced HF damage on 4 configural tasks: (a) negative patterning, (b) the Gallagher-Holland task, (c) transverse patterning, and (d) place learning. Rats with IBO lesions performed like controls on the Gallagher-Holland task (replicating M. Gallagher & P. C. Holland) but were impaired on negative patterning, transverse patterning, and place learning. In contrast, rats with K–C lesions were impaired on all 4 tasks. The implications of these results for theories of HF function are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
4.
CJ Grupi PJ Moffa PC Sanches SA Barbosa GM Bellotti FJ Pileggi 《Canadian Metallurgical Quarterly》1994,40(2):129-136
In vitro effects of two bioactive forms of pituitary adenylate cyclase activating polypeptide (PACAP): PACAP-38 and PACAP-27 were studied on rabbit vascular and non-vascular smooth muscle. Segments of the ovarian artery and muscle strips from the fallopian tube were used. Two series of experiments were performed on vessels: the dose-response relationship of PACAP-38 (10(-10)-10(-7) M) was established on noradrenaline- (NA, 10(-6) M) contracted vessels. In the other set of experiments the contractile effect of 10(-8)-10(-4) M NA added cumulatively, was studied on arterial segments incubated with PACAP-38 (10(-7) M), PACAP-27 (10(-7) M) or VIP (10(-7) M). The effect of PACAP-38, PACAP-27 and VIP (10(-10)-10(-6) M) was investigated on spontaneously contracting smooth muscle of the fallopian tube. Longitudinally as well as transversally cut specimens were investigated. PACAP-38 produced a significant dose-related relaxation on the NA-precontracted vessels. However, pre-incubation of the vessels with 10(-7) M PACAP-38, PACAP-27 and vaso active intestinal polypeptide (VIP) did not induce a general rightward shift of the NA concentration-response curves, although a tendency to inhibition in the low-dose interval was observed. The peptides caused a significant, dose-dependent inhibition of both frequency and amplitude on the fallopian tube smooth muscle activity. The effects of the three peptides on longitudinally as well as transversally cut specimens were alike. 相似文献
5.
JL Vallet 《Canadian Metallurgical Quarterly》1995,53(6):1436-1445
Effects of extracellular matrices (ECM) and the plasminogen activator (PA) system on outgrowth of sheep inner cell masses (ICM) and trophectoderm in vitro were investigated. Experiment 1 evaluated the effects of plasminogen and ECM type on ICM and trophectodermal outgrowth, on glass Lab-Tek chamber slides coated with collagen IV, fibronectin, or laminin. ICM outgrowth areas were reduced (p < 0.05) by plasminogen and were greatest (p < 0.05) on fibronectin. Trophectodermal outgrowth was not supported in this system. Experiment 2 evaluated the effects of PA inhibitor-2 (PAI-2) or antiserum to urokinase-type PA (anti-uPA) on ICM outgrowth on fibronectin. Numbers of cells in the outgrowths were increased (p < 0.05) with PAI-2, and anti-uPA had no effect (p > 0.10). Experiment 3 evaluated the relationship between PA production and ECM type on ICM and trophectodermal outgrowth in microdrop cultures. PA production by ICM was greatest (p < 0.05) on fibronectin, but no differences (p > 0.10) were observed for trophectoderm. PA production was not correlated with ICM outgrowth areas (r = -0.12; p = 0.72) or numbers of cells in the ICM outgrowths (r = 0.09; p = 0.74) but was correlated with ICM areas (r = 0.75; p < 0.01) and numbers of cells in trophectodermal outgrowths (r = 0.57; p = 0.01). These results suggest that type of ECM, culture system, and alterations in the PA system influence cellular outgrowths by ICM and trophectoderm. 相似文献
6.
Desferrioxamine (DES) protective effect against 1-methyl-4-phenylpyridinium (MPP+) toxicity was evaluated by microdialysis in the substantia nigra. DES (1 microM to 10 mM) co-perfused with MPP+ (2.5 mM) on day 1, produced on day 2 a higher dopamine extracellular output after perfusion of MPP+ than in control-MPP+ perfusion experiments, in which no DES was administered on day 1. Both Ringer's perfusion alone (control-Ringer) and co-perfusion of DES (10 mM) with MPP+ (2.5 mM) on day 1 produced on day 2 similar increases in dopamine extracellular output after a second MPP+ perfusion. In the control-Ringer experiment, note that the MPP+ on day 2 is the first MPP+ perfusion. Perfusion of FeCl3 (200 microM) along with MPP+ (2.5 mM) and DES (100 microM) on day 1 completely abolished on day 2 the neuroprotective effect found with MPP+ (2.5 mM) and DES (100 microM). The ability of DES to protect against MPP+ toxicity may indicate a therapeutic strategy in the treatment of diseases when iron is implicated. 相似文献
7.
Comments on F. M. Levine and G. Fasnacht's (see record 1975-07966-001) article on token learning, focusing on (1) the validity of the overjustification hypothesis, (2) the nature of intrinsic interest, and (3) the implications of overjustification studies for token economies. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
8.
The aim of the present study was to investigate the effect of nitric oxide (NO) on the relaxant activity of caffeine and aminophylline on rat myometrial strips. Uteri of pregnant Wistar rats were removed and suspended in 10-ml organ baths containing 37 degreesC Krebs bicarbonate solution gassed with 95% O2 and 5% CO2. The significance of the results was assessed by Student's t-test and P<0.05 was considered significant. A relaxant effect was observed with 10(-5)-10(-2) M caffeine (n=8) and aminophylline (n=6) on pregnant rat myometrial strips precontracted with 64 mM K+ (IC50=4.21+/-0.35 and 4.25+/-0.26, respectively). Incubation with 10(-5) M methylene blue, 10(-5) M haemoglobin, 10(-6) M Nomega-nitro-L-arginine methyl ester (L-NAME), 2x10(-7) M forskolin and 10(-6) M zaprinast exerted no effect on the relaxations (P>0.05). When the concentration of external Ca2+ was decreased to 0.5 mM or increased to 4.5 mM from the control level of 1.5 mM, the concentration-inhibition curves for caffeine and aminophylline shifted to the left or to the right, respectively. Our results suggest that: (1) the L-arginine-NO-cGMP system has no effect on the inhibition induced by caffeine and aminophylline on K+ induced contractions of pregnant rat myometrium; (2) this inhibitory effect is not mediated by cAMP; (3) cGMP does not play a role on the relaxant effect of these drugs; and (4) that Ca2+ plays the major role on the relaxations obtained with methylxanthine derivatives on pregnant rat uterus. (c) 1998 The Italian Pharmacological Society. 相似文献
9.
The potency of a series of anticholinesterase (anti-ChE) agents and serotonin-related amines as inhibitors of the aryl acylamidase (AAA) activity associated with electric eel acetylcholinesterase (AChE) (EC 3.1.1.7) and horse serum butyrylcholinesterase (BuChE) (EC 3.1.1.8) was examined and compared with the potency of the same compounds as ChE inhibitors. Neostigmine, physostigmine, BW 284C51, (+/-)-huperzine A, E2020, tacrine, edrophonium and heptyl-physostigmine were, in that order, the most potent in inhibiting eel AChE-associated AAA activity, their inhibitor constant (Ki) values being in the range 0.02-0.37 microM. The rank order of the same compounds as AChE inhibitors basically paralleled that of AAA, although they were in general stronger on AChE (Ki = 0.001-0.05). The peripheral anionic site inhibitors propidium and gallamine were inactive on AChE-associated AAA. Serotonin and its derivatives were slightly stronger on AAA (Ki = 7.5-30 microM) than on AChE (Ki = 20-140 microM). Tacrine (IC50 = 0.03 microM), diisopropylfluorophosphate (IC50 = 0.04 microM), heptyl-physostigmine (IC50 = 0.11 microM), physostigmine (IC50 = 0.15 microM) and tetra-iso-propylpyrophosphoramide (iso-OMPA) (IC50 = 0.75 microM) were the most potent in inhibiting horse serum BuChE-associated AAA activity. Serotonin and related amines were very weak on BuChE-associated AAA activity. These results indicate that the inhibitory potencies of the active site anti-ChE agents on the AAA activity associated with eel AChE and horse serum BuChE are closely correlated with their action on the respective ChE. In addition, the efficacy of tacrine, E2020, heptyl-physostigmine and (+/-)-huperzine A in the treatment of Alzheimer's disease is unlikely to be related to the action of these drugs on ChE-associated AAA. 相似文献
10.
Examines a model of dyadic interpersonal equilibrium, based on Piaget's (1941, 1965) work on social equilibrium of interpersonal values. Piaget's conception rests basically on the idea of an interpersonal balance between the action of one individual and the satisfaction of the other individual. The aim pursued here is to reformulate and to reinterpret Piaget's interpersonal equilibrium, placing special emphasis on the problem of interpersonal comparisons. (French summary) (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
11.
46 chronic schizophrenics with at least 3 years of continuous hospitalization, no secondary diagnosis of brain damage, age under 59, and all stabilized on their current medication were tested twice on the Trail Making Test (TMT) with 6 wk. between testings. The experimental group (N = 28) had the 2nd testing, following 5 weeks of being off all drugs. Results show: (a) previous findings that TMT is not a sensitive test for organicity with schizophrenics are true whether or not Ss are on tranquilizers, (b) no relationship between amount of drugs and performance on TMT, and (c) drug withdrawal did not affect performance on TMT. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
12.
Comments on A. Bandura's (see record 1979-08427-001) social learning theory, focusing on Bandura's stances on (1) psychologists who have no regard for environmental influences, (2) determinism, (3) reflective thought, (4) psychic agents, and (5) traditional behaviorists. Bandura's theory has not rendered the telic possibilities in human behavior obsolete. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
13.
Criticizes the study by D. B. Cohen and J. M. Horn (see PA, Vol 52:Issue 6) which tested H. Eysenck's theory of extraversion on the following grounds: (a) unsuitable sample, (b) lack of proper experimental control, (c) failure to choose appropriate parameter values, and (d) improper theoretical formulation. It is argued that the results throw little light on the nature of extraversion-introversion nor on the theory of cortical inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
14.
The effects of intracellular signal transduction system inhibitors on the inward current (Iin) caused by achatin-I (Gly-D-Phe-Ala-Asp), an Achatina endogenous tetrapeptide having a D-phenylalanine residue, applied locally onto the neurone tested, were examined under voltage clamp using two identifiable Achatina giant neurone types, v-RCDN (ventral-right cerebral distinct neurone) and PON (periodically oscillating neurone). H-89 (N-[2-(p-bromocinnamylamino)-ethyl]-5-isoquinolinesulfonamide) (adenosine-3',5'-cyclic monophosphate (cyclic AMP)-dependent protein kinase inhibitor) markedly suppressed the achatin-I-induced Iin on PON, whereas this drug was ineffective on the Iin of v-RCDN. Dose (pressure duration)-response study of achatin-I on PON in a physiological solution and in the presence of H-89, and Lineweaver-Burk plot of these data, indicated that H-89 inhibited the Iin in a noncompetitive manner. KT5823 (N-methyl-(8R*,9S*,11S*)-(-)-9-methoxy-9-methoxycarbonyl-8-methyl-2,3,9, 10-tetrahydro-8,11-epoxy-1H,8H,11H-2, 7b,11a-triazadibenzo[a,g]cycloocta[c,d,e]-trinden-1-on e) (guanosine-3',5'-cyclic monophosphate (cyclic GMP)-dependent protein kinase inhibitor) suppressed the achatin-I-induced Iin of v-RCDN in mainly noncompetitive and partly uncompetitive manners, but this drug had no effect on the Iin of PON. W-7 (N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide) (calmodulin inhibitor) suppressed noncompetitively the Iin of PON, but this drug had no effect on the Iin of v-RCDN. IBMX (3-isobutyl-1-methylxanthine) (cyclic nucleotide phosphodiesterase inhibitor) enhanced the achatin-I-induced Iin of v-RCDN, but this drug was ineffective on the Iin of PON. However, IBMX might have effects on the achatin-I receptor sites on v-RCDN. These findings suggest multiple intracellular signal transduction pathways mediating the achatin-I-induced Iin: the Iin of PON is via cyclic AMP-dependent and probably Ca2+/calmodulin-dependent protein kinases, and that of v-RCDN via cyclic GMP-dependent protein kinase. Other signal transduction system inhibitors including calphostin C (2-[12-[2-(benzyloxy)-propyl]-3, 10-dihydro-4,9-dihydroxy-2,6,7,11-tetramethoxy-3,10-dioxo-1-per yleny]-1 -methylethyl carbonic acid 4-hydroxyphenyl ester) (protein kinase C inhibitor) did not significantly affect the Iin of both v-RCDN and PON. 相似文献
15.
Little empirical research has identified the impact of managed health care (MHC) on various types of predoctoral internship sites. Thus, the authors examined (a) the extent to which MHC affected such sites, (b) the types of sites most affected by MHC, and (c) internship training directors' (ITDs') perceptions of MHC's influence on specific issues in their sites. Overall, ITDs indicated that MHC had generally little impact on internship agencies to date. However, ongoing monitoring of MHC's effects on internship sites is warranted. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
16.
Administered a modified version of a Piagetian test on the concept of relative velocity (including questions on the duration of relative displacements) to 96 children placed in age groups of 7, 9, 11, and 13 yr. It was found that (a) the developmental stages of the concept were comparable to those observed by Piaget except for formal operations which seem to evolve later; (b) the combination of 2 movements of same direction but unequal velocity is more difficult to synthesize than any other; (c) success on the problem of durations is not a prerequisite of at least partial success on the problem of velocities; and (d) complete success on the problem of velocities is not necessarily verbalized in spatio-temporal terms. To explain the difficulty observed in synthesizing velocities, the importance of the instructions (e.g., specifying the speed of each mobile) and of changes in the spatial order of the mobiles was emphasized. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
17.
The objectives of the present study were to determine the effects of iontophoretically-applied noradrenergic agonists on the unit activity of physiologically characterized superficial dorsal horn neurons in the barbiturate-anesthetized cat spinal cord, and to determine if a relationship exists between the effects produced by these agents and neuron modality. The effects of norepinephrine (NE), clonidine (CLON, a selective alpha2-agonist) and phenylephrine (PE, a selective alpha1-agonist) on spontaneous and D,L-homocysteic acid (DLH)-evoked unit activity were examined for 68 superficial dorsal horn neurons. Iontophoretically applied NE inhibited (40% of the cells examined) and excited (39% of the cells examined) unit activity. Mixed effects (i.e., inhibition and excitation) on unit activity also were observed (10% of the cells examined), and NE had no effect on the unit activity of some cells (11% of the cells examined). Excitation was the predominant effect produced by CLON (62% of the cells examined); however, inhibition (19% of the cells examined), mixed effects (5% of the cells examined), and no effects on unit activity (14% of the cells examined) also were observed. Iontophoretically applied PE inhibited (46% of the cells examined) and excited (36% of the cells examined) unit activity. Mixed effects on unit activity also were observed (4% of the cells examined), and PE had no effect on the unit activity of some cells (14% of the cells examined). Whether NE, CLON or PE exerted excitatory or inhibitory effects on unit activity did not depend on neuron modality. 相似文献
18.
19.
Seidenberg Michael; Giordani Bruno; Berent Stanley; Boll Thomas J. 《Canadian Metallurgical Quarterly》1983,51(3):406
121 9–14 yr olds were divided into 4 groups based on their WISC-R Full Scale IQ score: (a) 70–79, (b) 80–89, (c) 90–99, and (d) >100. Performance of these 4 groups was compared on the Halstead-Reitan Neuropsychological Test Battery for Children (HRNTBC) using a multiple-levels-of-inference framework: (a) level of performance, (b) pattern of performance, and (c) right–left hand differences. Results indicate a significant influence of IQ on level of performance for 6 of 14 test measures. Tests of problem-solving abilities, language skills and auditory perceptual analysis were most affected, whereas little influence was observed for tests of basic and simple motor functions. Right–left hand differences were also unaffected by IQ level. Results call attention to the importance of considering IQ level in the interpretation of performance on the HRNTBC. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
20.
165 18–50 yr old active-duty military, male, psychiatric inpatients with DSM-III diagnoses of schizophreniform disorder (n?=?71), schizophrenia (n?=?40), bipolar disorder—manic type (n?=?25), and unipolar depression (n?=?29) were compared on a variety of demographic, behavioral, and personality (MMPI) measures to determine the unique characteristics of schizophreniform disorder. Schizophreniform and schizophrenic Ss did not differ on any of the demographic or behavioral measures, but they differed significantly on the MMPI when age was controlled for by means of multivariate ANCOVA. Conversely, schizophreniform and bipolar manic Ss differed on the demographic correlates and on 1 behavioral measure (i.e., hyperactivity) but failed to differ on the MMPI. Schizophreniform and unipolar Ss, on the other hand, differed widely on all 3 sets of correlates. It is suggested that some schizophreniform patients will likely satisfy the criteria for schizophrenia if the diagnostician waits long enough (i.e., 6 mo). (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献