Phosphorus deficiency, parathyroid hormone and bone resorption in the growing rat

Sham-operated and parathyroidectomized (PTX) rats were divided into two pair-fed groups, one on a normal mineral intake (0.5% Ca, 0.3% P), the other on a regimen low in phosphorus (0.5% Ca, 0.03% P). P depletion led to a drop in plasma P and urine P, a rise in plasma Ca and a marked rise in urine Ca, a drop in serum magnesium and a rise in urine Mg. The changes were more pronounced in the PTX animals, but final values were the same in both groups. Parallel bone-seeking isotope (85Sr, 177Lu, 237Np) studies in nonablated animals revealed an increase in the urinary nuclide output and in the urine/tibia ratio in P-deficient animals. Normal and primary bone osteocytes decreased and enlarged osteocytes increased as a result of P deficiency; osteoclasts and osteoblasts also increased. Bone composition showed a drop in ash content and a rise in water, with a light decrease in both Ca and P, and a corresponding rise in hydroxyproline and nitrogen in the P-deficient animals. The results are interpreted to mean that P-deficiency in the young growing rat leads to an increase in bone resorption which occurs also in the absence of parathyroid hormone (PTH). The fact that final values were similar in the control and PTX P-deficient animals suggests that steady-state regulation can also occur without PTH. Because P-deficiency leads to rapid hypercalcemia and rapid marked hypercalciuria, there may exist a mechanism for phosphate regulation which would then supersede Ca homeostasis. The change in serum and urine Mg levels may reflect a decrease in tubular Ca and Mg reabsorption associated with P-deficiency.     

Réalisation d'un appareil d'Analyse Thermique Différentielle pour l'étude des produits organiques,contrǒle par un thermomètre à contact variable et un autotransformateur tournant

New Differential Thermo Analysis Apparatus for the Testing of Organic Substances The authors describe, a new heating and regulating apparatus for the differential thermo analysis of organic substances in a range of ?100° to +300°C. The apparatus has a contact thermometer whose range can be changed by a right-left changeable synchronmotor. The heating capacity is changed with an automatically controlled regulating transformer which receives the regulating impulses apart from a contact thermometer from a R-C-part as well. It is therefore possible to divide heating and cooling in separate time and thermal steps. Again the control gives the amount of correction for the regulation of heating so that the reproducible thermal and time cycles are run which permit the accurate analysis of, for example, the transformation points of the triglycerides. Along with the circuit diagram and a functional diagram, two examples of thermograms taken with this apparatus are given.     

Mg-based hydrogen storage materials: Surface segregation in Mg2Cu and related catalytic effects

Fresh surfaces of Mg₂Cu polycrystals cleaved in UHV have been investigated by AES, XPS and X-ray induced AES at room temperature. They show chemical decomposition of the surface leading to pronounced increase of surface Mg content. In contrast to the Mg the Cu remains essentially metallic, even on air exposed samples. It is suggested that this segregation prevents the formation of a compact oxide or hydroxide layer, thereby enabling dissociation of molecular hydrogen at the metallic Cu precipitations and/or the metallic Mg₂Cu subsurface. The results support comparable conclusions drawn earlier for LaNi₅, FeTi and Mg₂Ni.     

Urinary complications of the resectable cancers of the cervix uteri (author's transl)

The authors studied the urinary complications following 721 operations performed between 1960 and 1974 for cervix uterin carcinoma. The surgical method was the one used at the Fondation Curie according to the protocol of treatment. They have noted that: --first, the surgical act as primary treatment (672 cases) was innocuous, as this series showed only 0,6% of the severe complications; in contrast, when the surgery is performed for a recurrence after a total dose irradiation, the severe complications raised to 8%; --secondly, the uretero-hydronephroses following this type of surgery are relatively frequent on the systematic urograms, but most of them are quite asymptomatic and without later sequelae only 0,3% of them required a surgical treatment. The authors analyse the factors influencing the ureteral stenoses, especially the extent of lymphadenectomy and the associated external irradiation. They studied too the ureteral stenoses due to a local recurrence.     

Role of causal attributions in dynamic self-regulation and goal processes.

A dynamic model of self-regulation and goal process was tested with student survey responses and exam scores over successive performance episodes. A model of goal processes related to performance within episodes was developed and supported in both instances. The locus and stability dimensions of causal attributions were examined as moderators of how self-regulation and goal processes develop over time in a between-episode model. Results of the between-episode model showed stability attributions as moderating goal achievement–self-efficacy change relations following both episodes, whereas the locus attributions moderated the goal achievement–satisfaction relationship only after the first exam. Findings were discussed in terms of the evolution of goal processes over time and the use of attributional framing interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence of sequential lift in growth of aligned multiwalled carbon nanotube multilayers

We synthesized aligned multiwalled carbon nanotube multilayers by aerosol-assisted catalytic chemical vapor deposition through sequential injections of aerosols containing both carbon and catalyst precursors. Each sequence was traced by a specific duration or precursor mixture, with the carbon source being possibly enriched in (13)C isotope labels. We discovered that any sequence involved the growth of a new layer on the substrate surface, under any pre-existing one by lifting it up, giving definitive evidence of a base-growth mechanism.