Dynamic external fixation for distal radius fractures

Thirty adult patients with closed comminuted and mostly intraarticular fractures of the distal radius were treated by closed reduction and immobilization with a dynamic external wrist fixator during a 2-year period. In 13 patients with severely comminuted and unstable fractures, additional Kirschner wires were used. After 10 to 14 days of rigid fixation in neutral position, the motion element was unlocked to allow up to 30 degrees flexion. Six weeks later, the fixator was removed. The patients then were observed for an average of 24 weeks. An excellent functional outcome was seen in 6 patients (20%), a good outcome in 20 patients (67%), and a fair outcome in 4 patients (13%). Anatomically, 15 patients (50%) had an excellent result, 14 (47%) a good outcome, and 1 (3%) a fair outcome. Only minimal loss of reduction averaging 1 degree palmar tilt was seen during mobilization. There were 2 major complications: 1 deep Kirschner wire tract infection and 1 index metacarpal fracture. Minor complications such as sensory disturbances and pin tenderness were present but recovered completely after removal of the fixator. This study provides promising data and offers an alternative method in the treatment of distal radius fractures with severe comminution. In cases with postreductive unstable fragments, additional Kirschner wires should be used to allow early mobilization of the wrist.     

Irradiation induced creep of ceramic nuclear fuels

This contribution gives a review of the experimental results and accompanying theoretical considerations. The mechanisms considered for irradiation creep are: relaxation of elastic stresses by fission spikes, promotion of dislocation slide by thermal spikes, preferential, stress-orientated nucleation of dislocation loops and preferential growth of dislocation loops. A survey over the irradiation creep rates attributed to steady-state creep shows $\text{ε}{}_{\mathrm{irr}}\text{~ σ · F}$ for oxide fuel in the stress and fission rate ranges of $\text{σ = 10–50}\text{MN/m}{}^2$ and $\text{F = 3 × 10}{}^{12}\text{–1 × 10}{}^{14}\text{f/cm}{}^3\text{· s}$ at burnups < 3%. There seems to be a continuous increase of the irradiation creep rate of oxide fuels with increasing temperature. However, that increase cannot be directly interpreted through a thermally activated process. It seems that the irradiation creep rate will also depend on fuel porosity, on plutonium distribution in mechanically blended UO₂-PuO₂, but not substantially on the plutonium content per se. Some results were already given for carbide and nitride fuels, which show the irradiation creep rate to be lower by about a factor of 10 than for oxide fuel under comparable conditions. Primary irradiation creep has been observed up to $\text{(3–5) × 10}{}^{19}\text{f/cm}{}^3$ and could prevail up to $\text{1 × 10}{}^{20}\text{f/cm}{}^3$.     

A measurement of the irradiation-induced creep of mixed carbide nuclear fuel

In the BR 2 reacior at Mol, Belgium, a measurement of the irradiation induced creep of mixed carbide nuclear fuel up to high burnup was carried out The dependence upon applied stress and burnup of 95% dense (U, Pu) C was measured within a temperature range between 500 and 720°C and at fission rates between 1.0−1.5 × 10¹⁴ f/cm³ s. The used irradiation device was a Confluent-type capsule that allowed a variation of stress as well as temperature during irradiation. The length changes of the fuel specimen were determined by means of the microwave cavity resonance method. The obtained creep rates are proportional to stress and burnup-independent. The irradiation creep rates are about one order of magnitude below those of mixed oxide fuel. The fission product swelling rate increased with burnup form initially 1.2 to 3.0 vol% per % burnup. At stress changes the fuel showed a transient swelling up to 0.2 vol%. The theoretical background of carbide irradiation creep is briefly discussed.     

新“船驼”——寻求阿姆斯特丹与阿尔默勒之间新关系的研究型设计

所谓的“船驼”（scheepskameel）是在17世纪时开始使用的．这是一种浮坞,是当时东印度公司的船只驶入后在抵达浅滩前泊靠的地方．以确保吃水很深的船只从海上到阿姆斯特丹的可达性（图1）。装载有贵重物品的帆船必须要通过排空储水舱里的水来提升船位,从而能够穿越浅滩行驶;之后储水舱会被重新注满,船只继续调整方向驶入城市。     

Demographics, family history, premorbid functioning, developmental characteristics, and course of patients with deteriorated affective disorder

OBJECTIVE: This exploratory study examined the characteristics of a group of unusual and previously undescribed patients with major affective disorder who not only had been continuously symptomatic for prolonged periods of time but were also so functionally impaired that they required years of continuous care in psychiatric facilities or by family members. METHOD: Twenty-seven inpatients with major mood disorders and 29 inpatients with schizophrenia were recruited from a large state hospital; 27 outpatients with major mood disorders were recruited from an affiliated outpatient facility. The research battery included the Structured Clinical Interview for DSM-III-R--Patient Version, the Premorbid Adjustment Scale, and a semistructured interview designed to assess demographic, family history, developmental, and course information. RESULTS: Inpatients with deteriorated affective disorder differed from outpatients with nondeteriorated affective disorder along several important dimensions, including family history of mental illness, birth-related problems, physical disorders in infancy, premorbid functioning, presence of mixed episodes and rapid cycling, and medication non-compliance between hospitalizations. Inpatients with deteriorated affective disorder differed from inpatients with schizophrenia on the Premorbid Adjustment Scale. Patients with bipolar affective disorder differed from those with unipolar disorder on many of the variables associated with deterioration of functioning. CONCLUSIONS: Birth-related problems, physical disorders in infancy, and poor premorbid adjustment in childhood and adolescence appear to play an important role in deterioration of functioning among patients with unipolar depression. Disruption in treatment because of medication noncompliance and the appearance of mixed episodes and rapid cycling are associated with functional decline in bipolar affective disorder. Several characteristics previously considered specific to deterioration of functioning in schizophrenia, such as a high rate of birth complications and poor premorbid adjustment, appear to be associated with functional deterioration among patients with major depression as well.     

Evaluation of students' clinical competence.

In this article we describe a clinical proficiency review required of 3rd-year graduate students, and we present data from a study of its psychometric properties and utility. Students' oral and written case presentations were evaluated on seven dimensions by a six-member panel composed of faculty and students. Moderately high interjudge reliabilities were achieved, although the level of agreement between rater pairs was related to the level of similarity of their theoretical orientation. Significant correlations were obtained between panel ratings and those of current field placement supervisors, but not with supervisor's ratings from prior or subsequent placements. Performance on the clinical proficiency review was relatively independent of academic performance measures such as course grades and scores on a six-part comprehensive examination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Kriechverhalten von Cr-Ni-Stahl unter halogen- und Chalkogen-Einwirkung bei hohen Temperaturen

Creep behaviour of Cr-Ni steel under the influence of halogens and chalcogens at high temperatures. The influence of halogens and chalcogens on the creep behaviour of thin-walled Cr-Ni steel tubes has been investigated with regard to conditions existing in fuel pins of fast breeder reactors. In particular such reactive species were to be applied that cause a severe reduction in creep rupture elongation, an effect similar to stress corrosion cracking (SCC). The austenitic Cr-Ni steel X 10 CrNiMoTiB 15 15 (German material number 1.4970) was chosen as test material because of its special qualification as cladding material for fast breeder fuel pins. Test temperatures were 500 and 700°C. In order to generate well-defined halogen potentials, the halides of Cr, Fe, Ni and Cu were applied in mixtures with the respective metals. A mixture of CuO/Cu was used to supply a defined oxygen potential. The other chalcogens were applied in the elemental form only. The creep tests were mainly conducted on tube burst specimens at 500°C (blank test rupture time 500 h) and on tube tensile specimens at 700°C (blank test rupture time 150 h). Tube tensile tests offer a good possibility to analyse the influence of chemical attack with regard to the shape of the continuously recorded creep curve. The analysis allowed to classify the reactive species applied according to the degree, by which they enhanced crack formation and growth in the specimens. Creep failure at low rupture elongation occurred under conditions causing deep grain boundary attack of the cladding material. Such conditions existed in a combined halogen and oxygen environment. The reduction in rupture elongation was particularly marked when the halogen potential was sufficient to form Fe-halides. However, these statements do not apply to fluorine which did not cause a severe reduction in rupture elongation, either alone or in combination with oxygen.     

Thermal shock resistance of ceramic materials in melt immersion tests

A melt immersion test is applied to determine the relative resistance of ceramic materials to thermal shock failure under high heat flux conditions. The testing method is demonstrated mainly for Al₂O₃ pellets, while AlN is included to represent elevated thermal shock resistance. In order to quantify the resistance to crack formation, the critical temperature difference ΔT_c between sample and metal melt is determined from the failure probability distribution of a set of pellets.

In quenching tests correspondence of ΔT_c with the thermal shock parameter R = σ(1 − μ)/E was found, if the initial surface temperature of the sample was correctly estimated. This assessment was the main concern of the evaluation work.

ΔT_c resulting from heating tests was correlated with the maximum tensile stress in the sample by modeling calculations. The stress limits determined show that the ultimate bending strength could serve as a rough approximation for the materials tested.     

Irradiation-induced creep of mechanically blended porous UO2-PuO2 fuel

With regard to the behaviour of fast breeder reactor fuel, irradiation creep of mechanically blended, porous U_natO₂-15% PuO₂ was investigated. Some results for UO₂ are also quoted to clarify the dependence of creep rate on stress and temperature. The sintered density of the UO₂-PuO₂ samples amounted to 86% TD and 93,5% TD, their irradiation temperatures were between 300 and 1000°C, the stress in the samples at 15 and 40 MN/m², the fission rates between 2.5 and $\text{5 × 10}{}^{\mathrm{?9}}$ f/(U + Pu)-atom · s, and the maximum burnup at about 1%. The creep rates of UO₂-PuO₂ are much higher than previously measured on UO₂ of high density, but there was a good correspondence of the stress and temperature dependence. The difference of the creep rates cannot be explained only by the porosity of the UO₂-PuO₂ samples. Therefore the PuO₂ portion of the fuel, whose distribution is heavily inhomogeneous, is treated as additional “effective” porosity. By this means a suitable interpretation is obtained for the results below about 650°C. At higher temperatures, UO₂-PuO₂ of 86% TD showed a rapid initial densification up to about 93% TD, apparently together with a simultaneous homogenization of the fission-density distribution. The results measured could be interpreted without considering an influence of the Pu-content as such.