Quasi-Periodic Oscillations from Magnetorotational Turbulence

Quasi-periodic oscillations (QPOs) in the X-ray lightcurves of accreting neutron star and black hole binaries have been widely interpreted as being due to standing wave modes in accretion disks. These disks are thought to be highly turbulent due to the magnetorotational instability (MRI). We study wave excitation by MRI turbulence in the shearing box geometry. We demonstrate that axisymmetric sound waves and radial epicyclic motions driven by MRI turbulence give rise to narrow, distinct peaks in the temporal power spectrum. Inertial waves, on the other hand, do not give rise to distinct peaks which rise significantly above the continuum noise spectrum set by MRI turbulence, even when the fluid motions are projected onto the eigenfunctions of the modes. This is a serious problem for QPO models based on inertial waves.Comment: 4 pages, 2 figures. submitted to ap

Blunted Cystine–Glutamate Antiporter Function in the Nucleus Accumbens Promotes Cocaine-induced Drug Seeking

Repeated cocaine alters glutamate neurotransmission, in part, by reducing cystine–glutamate exchange via system xc−, which maintains glutamate levels and receptor stimulation in the extrasynaptic compartment. In the present study, we undertook two approaches to determine the significance of plasticity involving system xc−. First, we examined whether the cysteine prodrug N-acetylcysteine attenuates cocaine-primed reinstatement by targeting system xc−. Rats were trained to self-administer cocaine (1 mg/kg/200 μl, i.v.) under extended access conditions (6 h/day). After extinction training, cocaine (10 mg/kg, i.p.) primed reinstatement was assessed in rats pretreated with N-acetylcysteine (0–60 mg/kg, i.p.) in the presence or absence of the system xc− inhibitor (S)-4-carboxyphenylglycine (CPG; 0.5 μM; infused into the nucleus accumbens). N-acetylcysteine attenuated cocaine-primed reinstatement, and this effect was reversed by co-administration of CPG. Secondly, we examined whether reduced system xc− activity is necessary for cocaine-primed reinstatement. To do this, we administered N-acetylcysteine (0 or 90 mg/kg, i.p.) prior to 12 daily self-administration sessions (1 mg/kg/200 μl, i.v.; 6 h/day) since this procedure has previously been shown to prevent reduced activity of system xc−. On the reinstatement test day, we then acutely impaired system xc− in some of the rats by infusing CPG (0.5 μM) into the nucleus accumbens. Rats that had received N-acetylcysteine prior to daily self-administration sessions exhibited diminished cocaine-primed reinstatement; this effect was reversed by infusing the cystine–glutamate exchange inhibitor CPG into the nucleus accumbens. Collectively these data establish system xc− in the nucleus accumbens as a key mechanism contributing to cocaine-primed reinstatement

Cracking of RC School Building Due to Soil Expansion

The geotechnical investigations, the structural analyses and the remedial measures of a cracked reinforced concrete school building are presented in this paper. The building is located in Irbid, Jordan, where the soil is highly expansive and the volume change of the soil causes major destruction in the buildings in the area. Field and laboratory tests were performed on the foundation soil of the building to determine its swell potential and other engineering properties. The school building is modeled as a 3-D finite element model using Sap2000 code. The model is built based on results of geotechnical investigation. The results revealed structural deficiencies in building members (columns, beams and footings) due to the swelling gradient. Remedial measures were proposed and implemented to rehabilitate and strengthen the overstressed members. The repaired school has been under service since 2003. The school building performance is being under monitoring since then and has shown reliable performance

Effects of gamma irradiation on salted and frozen mullet fish during storage period

The objective of the present study was to investigate the influence of gamma irradiation on decontamination of microbial loud of salted and frozen mullet fish. Mullet fish samples were divided into two groups: The first group was frozen at – 20C° and the second group was dry salted with ordinary commercial refined salt at ratio 1 kg fish / 0.8 kg. Each group was subjected to 0, 2.5 and 5 kGy of gamma irradiation doses before storage period. The results showed that, gamma irradiation hadn’t any significant (P?0.05) effects on the chemical composition and minerals content of mullet fish samples under investigation. Gamma irradiation doses (2.5 and 5.0 kGy) had not significant remarkable effect at P?0.05 on sensory properties (appearance, odor, texture and color) of dry and frozen mullet fish samples neither at zero time nor during storage periods. Microbial aspects (total bacterial counts, coliform bacteria, salmonella, sporeforming bacteria and total molds and yeasts) were detected. Also it could be concluded that, gamma irradiation had a significant (P?0.05) decrease effects on microbial loud and improve the microbiological safety of salted and frozen mullet fishes without any adverse effects on their chemical contents and quality. Keywords: key words, Gamma irradiation, Salting, freezing, Mullet fish, Minerals, Microbial loud

Repeated \u3cem\u3eN\u3c/em\u3e-Acetylcysteine Administration Alters Plasticity-Dependent Effects of Cocaine

Cocaine produces a persistent reduction in cystine–glutamate exchange via system xc− in the nucleus accumbens that may contribute to pathological glutamate signaling linked to addiction. System xc− influences glutamate neurotransmission by maintaining basal, extracellular glutamate in the nucleus accumbens, which, in turn, shapes synaptic activity by stimulating group II metabotropic glutamate autoreceptors. In the present study, we tested the hypothesis that a long-term reduction in system xc− activity is part of the plasticity produced by repeated cocaine that results in the establishment of compulsive drug seeking. To test this, the cysteine prodrug N-acetylcysteine was administered before daily cocaine to determine the impact of increased cystine–glutamate exchange on the development of plasticity-dependent cocaine seeking. Although N-acetylcysteine administered before cocaine did not alter the acute effects of cocaine on self-administration or locomotor activity, it prevented behaviors produced by repeated cocaine including escalation of drug intake, behavioral sensitization, and cocaine-primed reinstatement. Because sensitization or reinstatement was not evident even 2–3 weeks after the last injection of N-acetylcysteine, we examined whether N-acetylcysteine administered before daily cocaine also prevented the persistent reduction in system xc− activity produced by repeated cocaine. Interestingly, N-acetylcysteine pretreatment prevented cocaine-induced changes in [35S]cystine transport via system xc−, basal glutamate, and cocaine-evoked glutamate in the nucleus accumbens when assessed at least 3 weeks after the last N-acetylcysteine pretreatment. These findings indicate that N-acetylcysteine selectively alters plasticity-dependent behaviors and that normal system xc− activity prevents pathological changes in extracellular glutamate that may be necessary for compulsive drug seeking

An asymptomatic case of peritoneal encapsulation: case report and review of the literature

Peritoneal encapsulation is a rare congenital anomaly characterised by a thin membrane of peritoneum encasing the small bowel to form an accessory peritoneal sac. We present a case of peritoneal encapsulation diagnosed incidentally in an 82 year old man undergoing laparotomy for colonic cancer. The sac was easily excised and surgery was otherwise uneventful. A discussion of the case and a review of the literature are presented

The Perception of Stakeholders towards Services Provided By Primary Health Care in Khartoum State, Sudan

Background: Sudan is a signatory country to Alma Ata Declaration and Primary Health Care (PHC) had been established since 1979. Although a lot of improvement is claimed to be achieved in PHC, some of the areas might be still far below the expectations. The objective of this study was to investigate the perception of the PHC stakeholders in Khartoum State about the PHC services provided and the adequacy of facilities used.Materials and Methods: This is a cross-sectional descriptive study conducted in Khartoum State, Sudan, between June and October 2015. A structured questionnaire was administered to a sample of PHC stakeholders. A 3-point Likert scale was used to indicate the quality of the different services provided and the facilities present. SPSS version 20 was used for analysis to calculate relevant descriptive statistical parameters.Results: Vaccination and care for pregnant ladies were perceived by respondents as present and adequate (100% and 95%, respectively). The other services that are perceived as adequate include: child health care, health education, chronic illness, drugs availability and the referral system. In sanitation services and feedback about patients referred to hospitals, only 20% and 4% were satisfied, respectively.Conclusion: Most of the PHC services were perceived as adequate by the respondents from Khartoum State. The services and facilities that were perceived as inadequate include sanitation services, communicable diseases, the referral system and provision of dental services.Key words: primary health care (PHC), stakeholders