Effect of X-rays on the Duration of Life of the Rice Weevil,Sitophilus Oryzae L.

Summary

The induction of UV-type damage by ionizing radiation in repair deficient strains of E. coli is reviewed. Both photoreactivable and non-photoreactivable types of damage can be observed. The induction of UV-type damage is largely independent of the presence of free-radical reactive agents (e.g. oxygen and thiols), but is dependent upon the energy of the photon–or electron–beam used, the radiation geometry and the optical absorbance of the extracellular medium. On the basis of calculations and experimental evidence, it is clear that one mechanism whereby such damage arises is through the generation of Cerenkov emission. However, small yields of UV-type damage can be produced using X-rays whose energy is below the threshold for production of Cerenkov emission. In this instance, the damage induction mechanism is thought to involve a direct excitation process.     

A mathematical model of the intracranial system including autoregulation

Abstract

Cerebral autoregulation plays an important role in the dynamic processes of intracranial physiology. This work develops a four-compartment, lumped-parameter model for the interactions of intracranial pressures, volumes, and flows as a test bed for examining the consistent inclusion of explicit autoregulation in mathematical models of the intracranial system. It is hypothesized that au.toregulation of the blood supply from the arterioles to the capillary bed can be modeled by allowing the flow resistance at the interface of the artery and capillary compartments in the model to be a function of pressure rather than a constant. The functional dependence on pressure of this resistance parameter is not specified in advance, but emerges naturally from the assumed relationship between pressure differences and flows. Results show that a constant flow from the artery to the capillary compartment can be maintained by a flow resistance which is directly proportional to the pressure difference between these two compartments. Oscillatory flow is re-established in the model at the capillary-cerebrospinal fluid and capillary-venous interfaces. [Neural Res 1997; 19: 441-450]     

Action Radioprotectrice de Chlorures Alcalino-terreux (BeCl2, SrCl2 et BaCl2) Sur La Croissance de L'orge

Summary

Il ressort de la comparaison avec l'eau distillée que des solutions 0,5 molaires de BeCl₂, SrCl₂ et BaCl₂ dans lesquelles sont plongés des grains d'orge avant l'irradiation déterminent (tout comme celles des autres chlorures alcalino-terreux) une radioprotection de la croissance du coléoptile et de la première feuille. Ce résultat est discuté en fonction de la pression osmotique et des propriétés biologiques des ions testés.     

Changes in daily leptin,ghrelin and adiponectin profiles following a diet with carbohydrates eaten at dinner in obese subjects

Background and aimsOur recently published randomised clinical trial evaluated the effect of a low-calorie diet with carbohydrates eaten at dinner. This dietary pattern led to lower hunger scores, and better anthropometric, biochemical and inflammatory outcomes compared to a standard low-calorie diet. In the same study, changes in diurnal secretion patterns of leptin, ghrelin and adiponectin were investigated.Methods and resultsSeventy-eight police officers (body mass index (BMI) > 30) were randomly allocated to experimental (carbohydrates at dinner) or control weight loss diets for 6 months. Sixty-three subjects finished the programme. On days 0, 7, 90 and 180 blood samples and hunger scores were collected every 4 h from 8:00 to 20:00. Hormonal profiles were available for 39.The dietary manipulation led to changes in daylight hormonal profiles in the experimental group. Leptin's secretion curve became convex, with a nadir later in the day (significant difference compared to baseline at morning and evening, p = 0.023, p = 0.021, respectively). Ghrelin's secretion curve became concave, peaking only in the evening hours. Adiponectin's curve was elevated only after the experimental diet (significant difference compared to baseline at afternoon, p = 0.044).ConclusionsWe propose that a low-calorie diet with carbohydrates eaten at dinner can modulate daytime hormonal profiles. Taken together with our earlier results, we believe this diet regime may prevent mid-day hunger, better support weight loss and improve metabolic outcomes compared to conventional weight loss diets.The trial is registered at controlled-trials.com, ISRCTN37829376, December 2009.     

Genotyping of the reduced folate carrier‐1 c.80G>A polymorphism by pyrosequencing technology: Importance of PCR and pre‐PCR optimization

When developing a genotyping assay by Pyrosequencing^? technology for the RFC1 (SLC19A1) c.80G>A polymorphism (rs1051266), unequal peak heights in the pyrograms were observed, probably due to unequal amplification of the mutated and wild‐type alleles. This rarely occurring problem could potentially render assignment of heterozygous genotypes uncertain. When the PCR conditions were studied, it was found that substitution of the dGTP nucleotide in the master mix by dGTP and dITP in proportion 1:1 largely overcame this problem. Heat denaturation of the DNA at 95°C before PCR also counteracted the problem. A combination of these two modifications of the standard pyrosequencing PCR protocol gave the best results. We conclude that, with these modifications, the RFC1 c.80G>A SNP can be reliably assayed by pyrosequencing.