Measurement of neutron induced 86Sr(n, 2n)85Sr reaction cross sections at different neutron energies

The cross-sections for ⁸⁶Sr (n, 2n)⁸⁵Sr reaction are measured at neutron energies 19.44 ± 1.02 MeV and 16.81 ± 0.85 MeV wherein there is scarcity of data. The standard neutron activation analysis technique and offline gamma ray spectroscopy have been employed for measurement and analysis of the data. The results are compared with experimental data available in EXFOR database, JEFF-3.3, JENDL-4.0, TENDL-2017 and ENDF/B-VIII.0 evaluated data. The theoretical prediction was incorporated using nuclear modular codes TALYS 1.8 and EMPIRE 3.2.2. A detailed comparative study of experimental results with the theoretical models and various major evaluations has been presented.

Effects of temporally varying inlet conditions on flow and particle deposition in the small bronchial tubes

The laminar flow in the small bronchial tubes is quite complex because of the presence of vortex-dominated, secondary flows. Factors contributing to this complexity are the unsteady nature of the inhale-exhale breathing cycle and the geometrical characteristics of the bronchial tubes. To investigate unsteady effects on flows and particle transport, unsteady inhalation flows at a 30-respiration-per-minute frequency, corresponding to a moderate activity level, were simulated for a three-generation, asymmetric, planar bronchial tube model. Ten-micron diameter water droplets were introduced at the inlet at different times during inhalation to develop particle destination maps. The differences in the flow fields and destination maps obtained at the unsteady peak flow and the comparable steady-state inflow condition were minimal. However, particles released at equivalent instantaneous off-peak inflow conditions produced different destination maps. The differences were attributed to the temporal variations of the fluid velocities and history effects.

Suppression of reactive oxygen species and nitric oxide by Asparagus racemosus root extract using in vitro studies

Recent clinical and experimental data showed the involvement of reactive oxygen species/nitrogen species (ROS/RNS) in many human pathophysiological conditions. Antioxidant activity of the aqueous (ARA) and ethanolic extracts (ARE) of Asparagus racemosus (AR) root were evaluated in a series of in vitro assays including ROS generation in chemicals and biological model systems. The dose-dependent ARA and ARE extracts showed the scavenging activity against DPPH (IC50 = 60.7 and 52.5 microg/ml), nitric oxide (IC50 = 141.9 and 63.4 microg/ml), superoxide (IC50 = 221 and 89.4 microg/ml), hydroxyl (IC50 = 318.7 and 208.8 microg/ml) and ABTS.+ (IC50 = 134.5 and 71.9 microg/ml) radicals. The antioxidant capacity of ARA and ARE were assessed for their reducing power using FRAP (Ferric Reducing antioxidant power) and potassium ferricyanide reducing methods as well as free radical scavenging capacity by TEAC (Trolox Equivalent Antioxidant Capacity) method. ARA and ARE extracts were also found to be effective at suppressing lipid peroxidation induced by Fe2+/ascorbate system in rat liver mitochondrial preparation (IC50 = 511.7 and 309.2 microg/ml, respectively). Further, ARA and ARE root extracts significantly decreased (P < 0.05) copper-mediated human LDL oxidation by prolongation of lag phase time with decline in oxidation rate, maximal yield of conjugated dienes, lipid hydroperoxides and malondialdehyde concentrations. The addition of ARA and ARE root extracts to human serum significantly reduced (P < 0.05) the formation of lipid peroxidation in medium. Trolox, alpha-tocopherol and mannitol were tested similarly to compare their antioxidant activities. In conclusion, antioxidant activity of ARE as compared to ARA extract is more effective which act as hydrogen donors, metal ion chelators, reducing agents, radical scavengers and anti-lipid peroxidative. These effects are attributed to the high amount of lipophilic phenolics content of ARE root extract.

Visualizing particle/flow structure interactions in the small bronchial tubes

Particle deposition in the small bronchial tubes (generations six through twelve) is strongly influenced by the vortex-dominated secondary flows that are induced by axial curvature of the tubes. In this paper, we employ particle destination maps in conjunction with two-dimensional, finite-time Lyapunov exponent maps to illustrate how the trajectories of finite-mass particles are influenced by the presence of vortices. We consider two three-generation bronchial tube models: a planar, asymmetric geometry and a non-planar, asymmetric geometry. Our visualizations demonstrate that these techniques, coupled with judiciously seeded particle trajectories, are effective tools for studying particle/flow structure interactions.

The relationship between neurological level of injury and symptomatic cardiovascular disease risk in the aging spinal injured

STUDY OBJECTIVES

To describe the distribution of clinically apparent cardiovascular disease (CVD) in people with long-term spinal cord injury (SCI) according to neurologic level and severity of injury.

DESIGN

Historical prospective study.

SETTING

Two British Spinal Injuries Centers.

PARTICIPANTS

Five hundred and forty-five individuals surviving at least 20 years with SCI were divided into three neurologic categories by level of injury and Frankel/ASIA grade as follows: Tetra ABC, Para ABC, and All D.

MAIN OUTCOME MEASURES

Cardiovascular disease outcomes defined by ICD/9 codes 390-448 and obtained through medical record review. Cardiovascular disease outcomes measured included All CVD, coronary heart disease (CHD), hypertension, cerebrovascular disease, valvular disease, and dysrhythmia.

RESULTS

After age-adjustment, the rates of All CVD were 35.2, 29.9, and 21.2 per 1000 SCI person-years in the Tetra ABC, Para ABC, and All D groups, respectively. Rates of All CVD increased with increasing age in all neurologic groups. Tetraplegic level of SCI conferred an excess 16% risk of All CVD (95% Confidence interval [CI], 0.93-1.46), a fivefold risk of cerebrovascular disease (relative risk [RR] 5.06; 95% CI, 1.21-21.15), and 70% less CHD (RR 0.30; 95% CI, 0.13-0.70) when compared with paraplegics. More complete SCI was associated with an excess 44% All CVD risk (95% CI, 1.16-1.77).

CONCLUSIONS

Risk of All CVD increased with increasing age, rostral level of SCI, and severity of SCI. More rostral level of SCI was associated with cerebrovascular disease, dysrhythmia, and valvular disease. Conversely, there was an inverse relationship between level of SCI and CHD

Toolbox: Sexual problems of disabled patients

Images

Regulation of mammalian circadian behavior by non-rod, non-cone, ocular photoreceptors

Circadian rhythms of mammals are entrained by light to follow the daily solar cycle (photoentrainment). To determine whether retinal rods and cones are required for this response, the effects of light on the regulation of circadian wheel-running behavior were examined in mice lacking these photoreceptors. Mice without cones (cl) or without both rods and cones (rdta/cl) showed unattenuated phase-shifting responses to light. Removal of the eyes abolishes this behavior. Thus, neither rods nor cones are required for photoentrainment, and the murine eye contains additional photoreceptors that regulate the circadian clock.

Influence of nicotine on myocardial stiffness and fibrosis during chronic ethanol use

Cardiomyopathy related to ethanol abuse is often accompanied by cigarette use. To examine if the major cardioactive component may intensify the abnormal function and composition induced by chronic ethanol, nicotine was administered orally, 2.5 mg bid, to a canine model receiving 36% of calories as ethanol for 6 months (group III). These animals were compared with group II receiving ethanol alone, group IV on nicotine alone, and controls (group I). In the intact, ventilated, anesthetized dog, left ventricular pressures and volumes were measured before and after dextran infusion and related to left ventricular collagen alterations. Basal heart rate, aortic pressure, and ejection fraction were comparable with controls. End-diastolic pressure and diastolic chamber stiffness (KPV) were significantly higher in the basal state and during dextran infusion in the three experimental groups, compared with group I. The increment was largest in the ethanol-nicotine group. Analysis of left ventricular myocardium revealed a rise of collagen concentrations in all three experimental groups, with an interstitial distribution on histochemical examination. Moreover, determination of advanced glycosylation endproducts, as a measure of alterations in collagen cross-links, revealed higher concentrations versus controls. The greater increase of diastolic stiffness in the nicotine-ethanol group occurred despite a similar concentration of fluorescent products as group II. Because the former had a larger increase of collage concentration, total cross-linked collagen content was presumably greater after the combined use of nicotine-ethanol. Thus, nicotine in relatively high dose when combined with ethanol, elicited a modest further increase in the left ventricular chamber stiffness and collagen concentration.

Three dimensional reconstruction of cross sectional intracoronary ultrasound: clinical or research tool?

Images

Long terminal repeat enhancer core sequences in proviruses adjacent to c-myc in T-cell lymphomas induced by a murine retrovirus

The transcriptional enhancer in the long terminal repeat (LTR) of the T-lymphomagenic retrovirus SL3-3 differs from that of the nonleukemogenic virus Akv at several sites, including a single base pair difference in an element termed the enhancer core. Mutation of this T-A base pair to the C-G C-G sequence found in Akv significantly attenuated the leukemogenicity of SL3-3. Thus, this difference is important for viral leukemogenicity. Since Akv is an endogenous virus, this suggests that the C-G in its core is an adaptation to being minimally pathogenic. Most tumors that occurred in mice inoculated with the mutant virus, called SAA, contained proviruses with reversion or potential suppressor mutations in the enhancer core. We also found that the 72-bp tandem repeats constituting the viral enhancer could vary in number. Most tumors contained mixtures of proviruses with various numbers of 72-bp units, usually between one and four. Variation in repeat number was most likely due to recombination events involving template misalignment during viral replication. Thus, two processes during viral replication, misincorporation and recombination, combined to alter LTR enhancer structure and generate more pathogenic variants from the mutant virus. In SAA-induced tumors, enhancers of proviruses adjacent to c-myc had the largest number of core reversion or suppressor mutations of all of the viral enhancers in those tumors. This observation was consistent with the hypothesis that one function of the LTR enhancers in leukemogenesis is to activate proto-oncogenes such as c-myc.