459 research outputs found

    Prospective memory functioning among ecstasy/polydrug users: evidence from the Cambridge Prospective Memory Test (CAMPROMPT)

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    Rationale: Prospective memory (PM) deficits in recreational drug users have been documented in recent years. However, the assessment of PM has largely been restricted to self-reported measures that fail to capture the distinction between event-based and time-based PM. The aim of the present study is to address this limitation. Objectives: Extending our previous research, we augmented the range laboratory measures of PM by employing the CAMPROMPT test battery to investigate the impact of illicit drug use on prospective remembering in a sample of cannabis only, ecstasy/polydrug and non-users of illicit drugs, separating event and time-based PM performance. We also administered measures of executive function and retrospective memory in order to establish whether ecstasy/polydrug deficits in PM were mediated by group differences in these processes. Results: Ecstasy/polydrug users performed significantly worse on both event and time-based prospective memory tasks in comparison to both cannabis only and non-user groups. Furthermore, it was found that across the whole sample, better retrospective memory and executive functioning was associated with superior PM performance. Nevertheless, this association did not mediate the drug-related effects that were observed. Consistent with our previous study, recreational use of cocaine was linked to PM deficits. Conclusions: PM deficits have again been found among ecstasy/polydrug users, which appear to be unrelated to group differences in executive function and retrospective memory. However, the possibility that these are attributable to cocaine use cannot be excluded

    The MACHO Project Large Magellanic Cloud Variable Star Inventory. VIII. The Recent Star Formation History of the LMC from the Cepheid Period Distribution

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    We present an analysis of the period distribution of 1800\sim 1800 Cepheids in the Large Magellanic Cloud, based on data obtained by the MACHO microlensing experiment and on a previous catalogue by Payne-Gaposchkin. Using stellar evolution and pulsation models, we construct theoretical period-frequency distributions that are compared to the observations. These models reveal that a significant burst of star formation has occurred recently in the LMC (1.15×108\sim 1.15\times 10^8 years). We also show that during the last 108\sim 10^8 years, the main center of star formation has been propagating from SE to NW along the bar. We find that the evolutionary masses of Cepheids are still smaller than pulsation masses by 7\sim 7 % and that the red edge of the Cepheid instability strip could be slightly bluer than indicated by theory. There are 600\sim 600 Cepheids with periods below 2.5\sim 2.5 days cannot be explained by evolution theory. We suggest that they are anomalous Cepheids; a number of these stars are double-mode Cepheids

    Structure of the ATP synthase catalytic complex (F(1)) from Escherichia coli in an autoinhibited conformation.

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    ATP synthase is a membrane-bound rotary motor enzyme that is critical for cellular energy metabolism in all kingdoms of life. Despite conservation of its basic structure and function, autoinhibition by one of its rotary stalk subunits occurs in bacteria and chloroplasts but not in mitochondria. The crystal structure of the ATP synthase catalytic complex (F(1)) from Escherichia coli described here reveals the structural basis for this inhibition. The C-terminal domain of subunit ɛ adopts a heretofore unknown, highly extended conformation that inserts deeply into the central cavity of the enzyme and engages both rotor and stator subunits in extensive contacts that are incompatible with functional rotation. As a result, the three catalytic subunits are stabilized in a set of conformations and rotational positions distinct from previous F(1) structures

    Long-Term Effects of the Periconception Period on Embryo Epigenetic Profile and Phenotype: The Role of Stress and How This Effect Is Mediated

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    Stress represents an unavoidable aspect of human life, and pathologies associated with dysregulation of stress mechanisms - particularly psychiatric disorders - represent a significant global health problem. While it has long been observed that levels of stress experienced in the periconception period may greatly affect the offspring's risk of psychiatric disorders, the mechanisms underlying these associations are not yet comprehensively understood. In order to address this question, this chapter will take a 'top-down' approach, by first defining stress and associated concepts, before exploring the mechanistic basis of the stress response in the form of the hypothalamic-pituitary-adrenal (HPA) axis, and how dysregulation of the HPA axis can impede our mental and physical health, primarily via imbalances in glucocorticoids (GCs) and their corresponding receptors (GRs) in the brain. The current extent of knowledge pertaining to the impact of stress on developmental programming and epigenetic inheritance is then extensively discussed, including the role of chromatin remodelling associated with specific HPA axis-related genes and the possible role of regulatory RNAs as messengers of environmental stress both in the intrauterine environment and across the germ line. Furthering our understanding of the role of stress on embryonic development is crucial if we are to increase our predictive power of disease risk and devise-effective treatments and intervention strategies

    Towards accurate and precise T1 and extracellular volume mapping in the myocardium: a guide to current pitfalls and their solutions

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    Mapping of the longitudinal relaxation time (T1) and extracellular volume (ECV) offers a means of identifying pathological changes in myocardial tissue, including diffuse changes that may be invisible to existing T1-weighted methods. This technique has recently shown strong clinical utility for pathologies such as Anderson- Fabry disease and amyloidosis and has generated clinical interest as a possible means of detecting small changes in diffuse fibrosis; however, scatter in T1 and ECV estimates offers challenges for detecting these changes, and bias limits comparisons between sites and vendors. There are several technical and physiological pitfalls that influence the accuracy (bias) and precision (repeatability) of T1 and ECV mapping methods. The goal of this review is to describe the most significant of these, and detail current solutions, in order to aid scientists and clinicians to maximise the utility of T1 mapping in their clinical or research setting. A detailed summary of technical and physiological factors, issues relating to contrast agents, and specific disease-related issues is provided, along with some considerations on the future directions of the field. Towards accurate and precise T1 and extracellular volume mapping in the myocardium: a guide to current pitfalls and their solutions. Available from: https://www.researchgate.net/publication/317548806_Towards_accurate_and_precise_T1_and_extracellular_volume_mapping_in_the_myocardium_a_guide_to_current_pitfalls_and_their_solutions [accessed Jun 13, 2017]

    Glial Hsp70 Protects K+ Homeostasis in the Drosophila Brain during Repetitive Anoxic Depolarization

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    Neural tissue is particularly vulnerable to metabolic stress and loss of ion homeostasis. Repetitive stress generally leads to more permanent dysfunction but the mechanisms underlying this progression are poorly understood. We investigated the effects of energetic compromise in Drosophila by targeting the Na+/K+-ATPase. Acute ouabain treatment of intact flies resulted in subsequent repetitive comas that led to death and were associated with transient loss of K+ homeostasis in the brain. Heat shock pre-conditioned flies were resistant to ouabain treatment. To control the timing of repeated loss of ion homeostasis we subjected flies to repetitive anoxia while recording extracellular [K+] in the brain. We show that targeted expression of the chaperone protein Hsp70 in glial cells delays a permanent loss of ion homeostasis associated with repetitive anoxic stress and suggest that this is a useful model for investigating molecular mechanisms of neuroprotection

    Observation and Interpretation of Microstructurally Induced Fluctuations of Back-Surface Signals and Ultrasonic Attenuation in Titanium Alloys

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    During ultrasonic inspection for flaws in engineering materials, it is important to understand the interactions between the inspecting beam and the microstructure in which flaws are embedded. It has been found that in certain materials such interactions can have dramatic effects on the characteristics of the beam as it propagates to and from a flaw and consequently can have deleterious effects on both flaw characterization and the probability of detection. It is well known that, the microstructure can backscatter energy, creating noise which can mask small flaws. In addition, a flaw signal can be attenuated by the removal of energy from the beam by absorption and scattering. Considerable progress has been made towards developing a theoretical understanding of these phenomena. For example, backscattered grain noise has been successfully modeled by Han and Thompson [1] for duplex microstructures that commonly occur in Ti-17 and Ti-6A1-4V alloys used in the rotating components of aircraft engines. In addition, attenuation has been modeled for randomly oriented, equiaxed, cubic microstructures [2], for textured, equiaxed, cubic, stainless-steel [3], and also for elongated textured microstructures [4]

    Development of a Hospital-based Massage Therapy Course at an Academic Medical Center

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    Background: Massage therapy is offered increasingly in US medical facilities. Although the United States has many massage schools, their education differs, along with licensure and standards. As massage therapy in hospitals expands and proves its value, massage therapists need increased training and skills in working with patients who have various complex medical concerns, to provide safe and effective treatment. These services for hospitalized patients can impact patient experience substantially and provide additional treatment options for pain and anxiety, among other symptoms. The present article summarizes the initial development and description of a hospital-based massage therapy course at a Midwest medical center.Methods: A hospital-based massage therapy course was developed on the basis of clinical experience and knowledge from massage therapists working in the complex medical environment. This massage therapy course had three components in its educational experience: online learning, classroom study, and a 25-hr shadowing experience. The in-classroom study portion included an entire day in the simulation center.Results: The hospital-based massage therapy course addressed the educational needs of therapists transitioning to work with interdisciplinary medical teams and with patients who have complicated medical conditions. Feedback from students in the course indicated key learning opportunities and additional content that are needed to address the knowledge and skills necessary when providing massage therapy in a complex medical environment.Conclusions: The complexity of care in medical settings is increasing while the length of hospital stay is decreasing. For this reason, massage provided in the hospital requires more specialized training to work in these environments. This course provides an example initial step in how to address some of the educational needs of therapists who are transitioning to working in the complex medical environment

    Maternal Obesity during Gestation Impairs Fatty Acid Oxidation and Mitochondrial SIRT3 Expression in Rat Offspring at Weaning

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    In utero exposure to maternal obesity increases the offspring's risk of obesity in later life. We have also previously reported that offspring of obese rat dams develop hepatic steatosis, mild hyperinsulinemia, and a lipogenic gene signature in the liver at postnatal day (PND)21. In the current study, we examined systemic and hepatic adaptations in male Sprague-Dawley offspring from lean and obese dams at PND21. Indirect calorimetry revealed decreases in energy expenditure (p<0.001) and increases in RER values (p<0.001), which were further exacerbated by high fat diet (45% kcals from fat) consumption indicating an impaired ability to utilize fatty acids in offspring of obese dams as analyzed by PRCF. Mitochondrial function is known to be associated with fatty acid oxidation (FAO) in the liver. Several markers of hepatic mitochondrial function were reduced in offspring of obese dams. These included SIRT3 mRNA (p = 0.012) and mitochondrial protein content (p = 0.002), electron transport chain complexes (II, III, and ATPase), and fasting PGC-1α mRNA expression (p<0.001). Moreover, hepatic LCAD, a SIRT3 target, was not only reduced 2-fold (p<0.001) but was also hyperacetylated in offspring of obese dams (p<0.005) suggesting decreased hepatic FAO. In conclusion, exposure to maternal obesity contributes to early perturbations in whole body and liver energy metabolism. Mitochondrial dysfunction may be an underlying event that reduces hepatic fatty acid oxidation and precedes the development of detrimental obesity associated co-morbidities such as insulin resistance and NAFLD
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