Showing papers by "University of North Texas published in 2000"
TL;DR: In this article, a two-stage approach based on the unstructured mean and covariance estimates obtained by the EM-algorithm is proposed to deal with missing data in social and behavioral sciences, and the asymptotic efficiencies of different estimators are compared under various assump...
Abstract: Survey and longitudinal studies in the social and behavioral sciences generally contain missing data. Mean and covariance structure models play an important role in analyzing such data. Two promising methods for dealing with missing data are a direct maximum-likelihood and a two-stage approach based on the unstructured mean and covariance estimates obtained by the EM-algorithm. Typical assumptions under these two methods are ignorable nonresponse and normality of data. However, data sets in social and behavioral sciences are seldom normal, and experience with these procedures indicates that normal theory based methods for nonnormal data very often lead to incorrect model evaluations. By dropping the normal distribution assumption, we develop more accurate procedures for model inference. Based on the theory of generalized estimating equations, a way to obtain consistent standard errors of the two-stage estimates is given. The asymptotic efficiencies of different estimators are compared under various assump...
1,412 citations
TL;DR: In order to explain the breakdown of the reward cascade due to both multiple genes and environmental stimuli (pleiotropism) and resultant aberrant behaviors, Blum united this hypodopaminergic trait under the rubric of a reward deficiency syndrome.
Abstract: The dopaminergic system, and in particular the dopamine D2 receptor, has been implicated in reward mechanisms. The net effect of neurotransmitter interaction at the mesolimbic brain region induces “reward” when dopamine (DA) is released from the neuron at the nucleus accumbens and interacts with a dopamine D2 receptor. “The reward cascade” involves the release of serotonin, which in turn at the hypothalmus stimulates enkephalin, which in turn inhibits GABA at the substania nigra, which in turn fine tunes the amount of DA released at the nucleus accumbens or “reward site.” It is well known that under normal conditions in the reward site DA works to maintain our normal drives. In fact, DA has become to be known as the “pleasure molecule” and/or the “antistress molecule.” When DA is released into the synapse, it stimulates a number a DA receptors (D1-D5) which results in increased feelings of well-being and stress reduction. A consensus of the literature suggests that when there is a dysfunction in ...
890 citations
TL;DR: This review has summarized published research concerning the tolerance of North American freshwater fishes to dynamic changes in temperature, i.e., tolerance is tested by methods that gradually change temperatures until biological stress is observed.
Abstract: Traditionally lower and upper temperature tolerances of fishes have been quantified in the laboratory via three different experimental approaches: the Fry or incipient lethal temperature (ILT), critical thermal (CTM) and chronic lethal (CLM) methodologies. Although these three experimental laboratory approaches generate endpoints which are quantitatively expressed as a temperature, are determined experimentally with random samples of fish acclimated to specific temperatures, and involve both time and temperature as major test variables, they do not quantify the same response. All three approaches generate valuable, albeit different, information concerning the temperature tolerance of a species. In this review we have summarized published research concerning the tolerance of North American freshwater fishes to dynamic changes in temperature, i.e., tolerance is tested by methods that gradually change temperatures until biological stress is observed. We found more than 450 individual temperature tolerances listed in 80 publications which present original dynamic temperature tolerance data for 116 species, 7 subspecies and 7 hybrids from 19 families of North American freshwater fishes. This total represents about 1/3 of the families and 1/6 of the known North American freshwater species. Temperature tolerance data were partitioned by experimental approach, i.e., critical thermal method (CTM) and chronic lethal method (CLM), and direction of temperature change. Although both CTM and CLM expose fish to dynamic changes in water temperature, these two methods differ in temperature change rates and test endpoints, and hence measure different aspects of thermal stress. A majority of the 80 studies employed CTM to assess temperature tolerance, in particular determination of CTmaxima. One or more CTmaxima has been reported for 108 fishes. Twenty-two fishes have reported highest CTmaxima of 40°C or higher. Several species in the family Cyprinodontidae have generated some of the highest CTmaxima reported for any ectothermic vertebrate. For a variety of reasons, data concerning tolerance of low temperatures are less plentiful. Low temperature tolerance quantified as either CTminima or CLminima were found for a total of 37 fishes. Acclimation temperature exerts a major effect on the temperature tolerance of most North American fish species and it is usually strongly linearly related to both CTmaxima and CTminima. Although we uncovered dynamic temperature tolerance data for 130 fishes, only a single dynamic, temperature tolerance polygon has been published, that for the sheepshead minnow, Cyprinodon variegatus.
793 citations
TL;DR: It is proposed that defects in various combinations of the genes for these neurotransmitters result in a Reward Deficiency Syndrome (RDS) and that such individuals are at risk for abuse of the unnatural rewards.
Abstract: The dopaminergic and opioidergic reward pathways of the brain are critical for survival since they provide the pleasure drives for eating, love and reproduction; these are called 'natural rewards' and involve the release of dopamine in the nucleus accumbens and frontal lobes. However, the same release of dopamine and production of sensations of pleasure can be produced by 'unnatural rewards' such as alcohol, cocaine, methamphetamine, heroin, nicotine, marijuana, and other drugs, and by compulsive activities such as gambling, eating, and sex, and by risk taking behaviors. Since only a minority of individuals become addicted to these compounds or behaviors, it is reasonable to ask what factors distinguish those who do become addicted from those who do not. It has usually been assumed that these behaviors are entirely voluntary and that environmental factors play the major role; however, since all of these behaviors have a significant genetic component, the presence of one or more variant genes presumably act as risk factors for these behaviors. Since the primary neurotransmitter of the reward pathway is dopamine, genes for dopamine synthesis, degradation, receptors, and transporters are reasonable candidates. However, serotonin, norepinephrine, GABA, opioid, and cannabinoid neurons all modify dopamine metabolism and dopamine neurons. We have proposed that defects in various combinations of the genes for these neurotransmitters result in a Reward Deficiency Syndrome (RDS) and that such individuals are at risk for abuse of the unnatural rewards. Because of its importance, the gene for the [figure: see text] dopamine D2 receptor was a major candidate gene. Studies in the past decade have shown that in various subject groups the Taq I A1 allele of the DRD2 gene is associated with alcoholism, drug abuse, smoking, obesity, compulsive gambling, and several personality traits. A range of other dopamine, opioid, cannabinoid, norepinephrine, and related genes have since been added to the list. Like other behavioral disorders, these are polygenically inherited and each gene accounts for only a small per cent of the variance. Techniques such as the Multivariate Analysis of Associations, which simultaneously examine the contribution of multiple genes, hold promise for understanding the genetic make up of polygenic disorders.
624 citations
TL;DR: Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils.
Abstract: Archaeological excavations at the site of Dmanisi in the Republic of Georgia have uncovered two partial early Pleistocene hominid crania. The new fossils consist of a relatively complete cranium and a second relatively complete calvaria from the same site and stratigraphic unit that yielded a hominid mandible in 1991. In contrast with the uncertain taxonomic affinity of the mandible, the new fossils are comparable in size and morphology with Homo ergaster from Koobi Fora, Kenya. Paleontological, archaeological, geochronological, and paleomagnetic data from Dmanisi all indicate an earliest Pleistocene age of about 1.7 million years ago, supporting correlation of the new specimens with the Koobi Fora fossils. The Dmanisi fossils, in contrast with Pleistocene hominids from Western Europe and Eastern Asia, show clear African affinity and may represent the species that first migrated out of Africa.
598 citations
TL;DR: People with average TC and LDL-C levels and below-average HDL-C may obtain significant clinical benefit from primary-prevention lipid modification, and on-treatment apoB, especially when combined with apoAI to form the apOB/AI ratio, may be a more accurate predictor than LDL- C of risk for first AMCE.
Abstract: Background—The Air Force/Texas Coronary Atherosclerosis Prevention Study (AFCAPS/TexCAPS) is the first primary-prevention study in a cohort with average total cholesterol (TC) and LDL cholesterol (LDL-C) and below-average HDL cholesterol (HDL-C). Treatment with lovastatin (20 to 40 mg/d) resulted in a 25% reduction in LDL-C and a 6% increase in HDL-C, as well as a 37% reduction in risk for first acute major coronary event (AMCE), defined as fatal or nonfatal myocardial infarction, unstable angina, or sudden cardiac death. This article describes the relation between baseline and on-treatment lipid and apolipoprotein (apo) parameters and subsequent risk for AMCEs. Methods and Results—With all available data from the entire 6605-patient cohort, a prespecified Cox backward stepwise regression model identified outcome predictors, and logistic regression models examined the relation between lipid variables and AMCE risk. Baseline LDL-C, HDL-C, and apoB were significant predictors of AMCE; only on-treatment apoB...
580 citations
TL;DR: This work shows that activated Ca(2+)/calmodulin-dependent protein kinases-I and -IV (CaMKI and CaMKIV) also induce hypertrophic responses in cardiomyocytes in vitro and suggests that the CaMK and calcineurin pathways preferentially target different transcription factors to induce cardiac hypertrophy.
Abstract: Hypertrophic growth is an adaptive response of the heart to diverse pathological stimuli and is characterized by cardiomyocyte enlargement, sarcomere assembly, and activation of a fetal program of cardiac gene expression. A variety of Ca(2+)-dependent signal transduction pathways have been implicated in cardiac hypertrophy, but whether these pathways are independent or interdependent and whether there is specificity among them are unclear. Previously, we showed that activation of the Ca(2+)/calmodulin-dependent protein phosphatase calcineurin or its target transcription factor NFAT3 was sufficient to evoke myocardial hypertrophy in vivo. Here, we show that activated Ca(2+)/calmodulin-dependent protein kinases-I and -IV (CaMKI and CaMKIV) also induce hypertrophic responses in cardiomyocytes in vitro and that CaMKIV overexpressing mice develop cardiac hypertrophy with increased left ventricular end-diastolic diameter and decreased fractional shortening. Crossing this transgenic line with mice expressing a constitutively activated form of NFAT3 revealed synergy between these signaling pathways. We further show that CaMKIV activates the transcription factor MEF2 through a posttranslational mechanism in the hypertrophic heart in vivo. Activated calcineurin is a less efficient activator of MEF2-dependent transcription, suggesting that the calcineurin/NFAT and CaMK/MEF2 pathways act in parallel. These findings identify MEF2 as a downstream target for CaMK signaling in the hypertrophic heart and suggest that the CaMK and calcineurin pathways preferentially target different transcription factors to induce cardiac hypertrophy.
521 citations
TL;DR: The authors build on extant literature and propose a theoretically grounded operationalization of the manufacturing flexibility construct, which indicates good support for the theorized taxonomy.
341 citations
TL;DR: Psychologists are offered a preliminary list of relevant issues for evaluating the merits of risk assessment in their forensic practices.
Abstract: Forensic psychologists are frequently asked to conduction evaluations of risk assessment. While risk assessment has considerable merit, recent applications to forensic psychology raise concerns about whether these evaluations are thorough and balanced. Forensic adult risk-assessment models stress risk factors, and deemphasize or disregard entirely the other side of the equation: protective factors. Mediating and moderating effects must also be considered. Moreover, base-rate estimates may produce erroneous results if applied imprudently to forensic samples without regard to their unstable prevalence rates or the far-reaching effects of settings, referral questions, and evaluation procedures. Psychologists are offered a preliminary list of relevant issues for evaluating the merits of risk assessment in their forensic practices.
311 citations
TL;DR: In this article, the impact of third parties and geopolitical factors on civil war duration is investigated. But the authors focus on the interdependent nature of third party interventions as they are distributed across the set of civil war combatants.
Abstract: Policymakers often trumpet the potential for third parties to stop the killing associated with civil wars, yet third parties as strategic actors also have incentives to encourage longer civil wars. We argue that in order to assess the influence of third parties on civil war duration, it is necessary to consider the interdependent nature of third party interventions as they are distributed across the set of civil war combatants. We also argue that it is important to consider the geopolitical context in which civil wars occur, rather than focusing solely on characteristics internal to these conflicts. To test our hypotheses about the impact of third parties and geopolitical factors on civil war duration, we rely on event history analysis and a sample of 152 civil wars for the period 1820–1992. We find empirical support for the idea that extremely long civil wars correspond to the equitable distribution of third party interventions—stalemates prolong wars. The analysis also indicates that separatist civil wars and ongoing civil wars in states proximate to the civil war state result in civil wars of longer duration. Finally, we find that when third parties raise the stakes of the conflict by engaging in the use of militarized force against the civil war state, the duration of these conflicts is reduced. In general, our analysis underscores the importance of modeling the interdependent and dynamic aspects of third party intervention as well as the world politics of civil wars when forecasting their duration and formulating policy.
296 citations
TL;DR: It appears that glasses, including prescription glasses and even non-prescription sunglasses, can offer measurable protection which results in a lower incidence of severe eye injuries to those wearing glasses.
Abstract: · Background: Trauma remains a major problem throughout the world. The prognosis of severe eye injuries is commonly bleak. This paper focuses on the epidemiology of eye trauma, the role of ocular epidemiology, and identification and reduction of risk factors. · Methods: An analysis of the first 8,952 patients reported with severe eye injuries, defined as those eye injuries resulting in permanent and significant (measurable and observable on routine eye examination) structural and/or functional changes to the eye, from the United States Eye Injury Registry as of 31 July 1998. · Results: The age of patients entered was from the 1st year of life to 103 years. Fifty-eight percent of those injured were less than 30 years of age. The male to female ratio was 4.6:1, reaching 7.4:1 in the fourth decade of life. Almost half of the injuries involved the retina, and 77% of the injured eyes required one or more surgical procedures, including a large proportion which have undergone vitreoretinal surgical procedures. · Conclusion: Injuries remain the most serious public health problem facing developed nations. Yet, a persistent inadequacy exists both in the standardized documentation of eye injuries and in their treatment. With appropriate surgical and medical intervention, a majority of the reported injured eyes recovered functional levels of visual acuity. It appears that glasses, including prescription glasses and even non-prescription sunglasses, can offer measurable protection which results in a lower incidence of severe eye injuries to those wearing glasses.
TL;DR: Investigation of perceived importance of physical activity and demographic variables and current physical activity level with specific reference to the CDC/ACSM guidelines for sufficient physical activity for a health benefit found implications for health and physical fitness researchers and practitioners are that they need to improve awareness of life span fitness benefits.
Abstract: Purpose: The purpose of this study was to investigate the relation between perceived importance of physical activity and demographic variables and current physical activity level with specific reference to the CDC/ACSM guidelines for sufficient physical activity for a health benefit. Methods: Physical activity levels were assessed by a telephone survey of 2002 households throughout the continental United States and the District of Columbia to determine whether the individuals met the CDC/ACSM physical activity guidelines. Results: Results indicate that 68% of the respondents are physically active below the CDC/ACSM criterion. Chi-square analysis revealed significant relationships between meeting the CDC/ACSM physical activity guidelines and 1) perceived importance of physical inactivity as a health risk (P <0.0001), and 2) gender (P < 0.0001). Logistic regression analysis revealed that having a greater awareness of the health risks of physical inactivity improved the odds ratio (OR = 1.40, 95% Cl = 1.21-1.62) of being sufficiently physically active for a health benefit by 40% (P <0.0001) and being a male improved the odds ratio (OR = 1.45, 95% CI = 1.17-1.79) of being sufficiently physically active for a health benefit by 45% (P < 0.0006). Conclusions: Implications for health and physical fitness researchers and practitioners are that they need to improve awareness of life span fitness benefits and develop intervention programs based on individuals' current physical activity levels.
TL;DR: The survival and differentiation of cultured retinal progenitor grafts upon subretinal transplantation are reported and suggest that cultured retina progenitors can be a viable reagents for therapeutic transplantation.
TL;DR: A neural network model for forecasting daily maximum ozone levels is developed and compared with two conventional statistical models, regression and Box–Jenkins ARIMA.
TL;DR: In this article, the authors studied the percolation threshold for fully penetrable discs by measuring the average location of the frontier for a statistically inhomogeneous distribution of DF discs.
Abstract: We study the percolation threshold for fully penetrable discs by measuring the average location of the frontier for a statistically inhomogeneous distribution of fully penetrable discs. We use two different algorithms to efficiently simulate the frontier, including the continuum analogue of an algorithm previously used for gradient percolation on a square lattice. We find that φc = 0.676 339 ± 0.000 004, thus providing an extra significant digit of accuracy to this constant. (Some figures in this article appear in colour in the electronic version; see www.iop.org)
01 Nov 2000
TL;DR: Preliminary results suggest that a meaningful ordinal ranking of content accessibility is not only possible, but also correlates significantly with the results of independent automated usability assessment procedures.
Abstract: Content accessibility is a key feature in highly usable Web sites, but reports in the popular press typically report that 95% or more of all Web sites are inaccessible to users with disabilities. The present study is a content accessibility compliance audit of 50 of the Web's most popular sites, undertaken to determine if content accessibility can be conceived and reported in continuous, rather than dichotomous, terms. Preliminary results suggest that a meaningful ordinal ranking of content accessibility is not only possible, but also correlates significantly with the results of independent automated usability assessment procedures.
TL;DR: Among these 21 species, temperature tolerance of brook charr and sheepshead minnow were the least and most affected by acclimation temperature, respectively, suggesting that Acclimation plays a larger role in tolerance of low rather than high temperatures.
Abstract: The relative effect of acclimation temperature on temperature tolerance was estimated from a geometrical partitioning of the temperature tolerance polygon of a fish species into three distinct zones relative to four key tolerance temperatures This approach yields a middle tolerance zone which is independent of acclimation temperature bounded by upper and lower acclimation dependent zones Acclimation dependent and independent temperature tolerance zones can be quantified by either areal or linear methods Both methods were applied to quantify the effect of acclimation temperature in 21 species of temperate fishes for which temperature tolerance polygons were available Temperature tolerance polygon areas of these 21 species ranged from 468 to 1380°C2 and are linearly related (r2=093, p<0001) to ultimate incipient upper lethal temperatures Although areal and linear partitioning methods yielded similar acclimation independent and dependent tolerances, estimates from the areal method incorporates additional information concerning the shape of the temperature tolerance polygon, in particular lower and upper lethal temperature plateaus Mean combined acclimation dependent and independent tolerance areas of these 21 species were not different, indicating that acclimation effectively doubles the temperature tolerance polygon Mean lower acclimation dependent area was nearly three times greater than mean upper acclimation dependent area, suggesting that acclimation plays a larger role in tolerance of low rather than high temperatures Among these 21 species, temperature tolerance of brook charr and sheepshead minnow were the least and most affected by acclimation temperature, respectively
TL;DR: In this paper, the authors compile, map, and evaluate regional patterns of nitrate occurrence in Texas groundwater using the Texas Water Development Board database and a geographic information system to map and evaluate the data.
TL;DR: In this paper, the antecedents of strategic reorientation, a change in strategy combined with change in at least two of organization structure, power distribution and control systems, presented by Lant, Milliken, and Batra (1992) by using archival data (1987-1993) for firms in the stable furniture and turbulent computer software industries, were reexamine and extended.
TL;DR: In this paper, the authors used spontaneously active neuronal networks derived from dissociated embryonic murine spinal cord and auditory cortex and grown on substrate-integrated thin-film microelectrodes to determine characteristic responses to the cannabinoid agonists anandamide and methanandamide (MA) reversibly inhibited spike and burst production in both tissue types.
TL;DR: By incorporating social subsystem costs and benefits in the IT investment process, decision-makers gain a greater appreciation for hidden costs andbenefits, and thus clarify anticipated IT payoff.
Abstract: Information technology (IT) investment decisions have traditionally focused on financial or technological issues. Responding to what appears to be a lack of payoff in IT investments, researchers as well as practitioners recently have suggested that traditional valuation analyses are incomplete and have called for additional work to identify "hidden" or seldom-considered costs and benefits. The present paper attempts to improve understanding of a chief source of these hidden costs and benefits: those changes in the social subsystem brought about by a new IT.Fifty IT decision-makers in a broad variety of industries were interviewed to gain insight into what, when, and how often social subsystem considerations are included in IT investment-decision processes. Data from the interviews show that in practice some of those issues are often minimized, excluded, or put off until the IT is implemented--thus affecting optimality of investment choices and IT payoff. The paper extends existing theory by describing systematic patterns of inclusion and exclusion of these costs and benefits. In addition, a decision aid is provided to help IT executives begin thinking about which social subsystem costs and benefits they should incorporate in various decisions. Suggestions are also made on how data regarding social subsystem costs and benefits might be gathered. By incorporating social subsystem costs and benefits in the IT investment process, decision-makers gain a greater appreciation for hidden costs and benefits, and thus clarify anticipated IT payoff.
TL;DR: PAK2, a member of the Rho family of GTPase-dependent kinases, regulates isometric tension development and myosin II RLC phosphorylation in saponin permeabilized endothelial monolayers and it is demonstrated that PAK2 can directly phosphorylate MLCK, inhibiting its activity and limiting the development of isometry tension.
TL;DR: LV-based pacing results in improved hemodynamics and a decrease in SNA compared with RV pacing in patients with LV dysfunction regardless of the QRS duration.
Abstract: Background—Although there have been few studies in which the hemodynamic effects of right ventricular (RV) and left ventricular (LV) pacing were compared with those of biventricular (BV) pacing, the autonomic changes during these different pacing modes remain unknown. We hypothesized that BV pacing results in improved hemodynamics and a decrease in sympathetic nerve activity (SNA) compared with single-site pacing. Methods and Results—Thirteen men with a mean ejection fraction of 0.28±0.7 were enrolled in the study. Arterial blood pressure (BP), central venous pressure (CVP), and SNA were recorded during 3 minutes of right atrial (RA)-RV, RA-LV, and RA-BV pacing at a rate 10 beats faster than sinus rhythm. BP was greater during LV (151±7/85±3 mm Hg) and BV (151±6/85±3 mm Hg) pacing than during RV pacing (146±7/82±3 mm Hg) (P<0.05). There were no differences in CVP among all pacing modes (P=0.27). SNA was significantly less (P<0.02) during both LV (606±35 U) and BV (582±41 U) pacing compared with RV pacing ...
TL;DR: For (gamma,nu)=(2,0) the authors obtain q=5/3, which differs from the value q=2 corresponding to the gamma=2 solutions available in the literature (nu<1 porous medium equation), thus exhibiting nonuniform convergence.
Abstract: We consider the d=1 nonlinear Fokker-Planck-like equation with fractional derivatives ( partial differential/ partial differentialt)P(x,t)=D( partial differential(gamma)/ partial differentialx(gamma))[P(x,t)](nu). Exact time-dependent solutions are found for nu=(2-gamma)/(1+gamma)(-infinity
TL;DR: In this article, the authors describe advantages and disadvantages of time-line interviewing and inductive content analysis for exploring and describing users' perceptions in various situational contexts using examples from a study of users' criteria for evaluation in a multimedia context.
Abstract: In studies of information users' cognitive behaviors, it is widely recognized that users' perceptions of their information problem situations play a major role. Time-line interviewing and inductive content analysis are two research methods that, used together, have proven extremely useful for exploring and describing users' perceptions in various situational contexts. This article describes advantages and disadvantages of the methods using examples from a study of users' criteria for evaluation in a multimedia context.
TL;DR: In this paper, it was shown that for the edge-of-chaos case, the usual Boltzmann-Gibbs-Shannon entropy is not appropriate and instead, the non-extensive entropy S q ≡ (1− ∑ i=1 W p i q ) (q−1), which is a special parameter q, the entropic index which must be given a special value q ∗ ≠ 1 (for q = 1 one recovers the usual entropy) characteristic of the edge of chaos under consideration.
TL;DR: Overall, the current findings indicate that changes in the level of caloric intake may reversibly affect the concentration of oxidized proteins and sufhydryl content and also retards the age-associated accumulation of oxidative damage.
Abstract: The age-associated increase in oxidative damage in ad libitum-fed mice is attenuated in mice fed calorically restricted (CR) diets. The objective of this study was to determine if this effect results from a slowing of age-related accumulation of oxidative damage, or from a reversible decrease of oxidative damage by caloric restriction. To address these possibilities, crossover studies were conducted in C57BL/6 mice aged 15 to 22 months that had been maintained, after 4 months of age, on ad libitum (AL) or a 60% of AL caloric regimen. One half of the mice in these groups were switched to the opposite regimen of caloric intake for periods up to 6 weeks, and protein oxidative damage (measured as carbonyl concentration and loss of sulfhydryl content) was measured in homogenates of brain and heart. In AL-fed mice, the protein carbonyl content increased with age, whereas the sulfhydryl content decreased. Old mice maintained continuously under CR had reduced levels of protein oxidative damage when compared with the old mice fed AL. The effects of chronic CR on the carbonyl content of the whole brain and the sulfhydryl content of the heart were fully reversible within 3-6 weeks following reinstatement of AL feeding. The effect of chronic CR on the sulfhydryl content of the brain cortex was only partially reversible. The introduction of CR for 6 weeks in the old mice resulted in a reduction of protein oxidative damage (as indicated by whole brain carbonyl content and cortex sulfhydryl), although this effect was not equivalent to that of CR from 4 months of age. The introduction of CR did not affect the sulfhydryl content of the heart. Overall, the current findings indicate that changes in the level of caloric intake may reversibly affect the concentration of oxidized proteins and sufhydryl content. In addition, chronic restriction of caloric intake also retards the age-associated accumulation of oxidative damage. The magnitude of the reversible and chronic effects appears to be dependent upon the tissue examined and the nature of the oxidative alteration.
TL;DR: Allylamine surfaces were still usable as cell growth substrates after three autoclaving cycles, 4 weeks under warm culture medium, and simple cleaning procedures, indicating the achievement of a long-lasting modification that did not require the repeated use of PDL before each seeding.
TL;DR: Increasing evidence indicates that Nape metabolism in plants shares functional similarities with NAPE metabolism in animal systems, including signal transduction and cellular protection, and the emerging role of released NAEs as lipid mediators in plant defense signaling represents an intriguing parallel to 'endocannabinoid signaling' in several mammalian cell types.