Experimental testing of magnesium and chrome-molybdenum-alloybicycle frames

Tests were made on a magnesium-alloy frame, as well as on bicycles made using such a frame. Strain gauges, a linear amplifier, an analog-to-digital converter, a microprocessor, a surface simulator and a personal computer were used to perform the measurements. It was found that the frame tested met the set of requirements laid down in the relevant standard concerning the static loads. The frame did not suffer permanent deformation. Making use of a field simulator; the elastic deformations obtained with different loads were compared on a bicycle assembled on an Mg (type: YBM-R-MTB, mass: 1245 gr., size: 19.5"/26") alloy frame. The low mass proved to be an added benefit. As far as the vibration tests are concerned, Mg frames performed well. The test results may make bicycle manufacturers reconsider constructional features and provide information for users in both competitive and mass sports     

Short-range order and melting anomalies in thin films

This paper presents electrical resistivity and superconductivity studies for the B1 (NaCl) structure oxides of titanium, vanadium, and niobium. In samples of nominal composition TiO _x , VO _x , and NbO _x ,x was varied from 0.8 to 1.2. It was found that all three of these oxides exhibit room-temperature electrical resistivities characteristic of metallic behavior. With decreasing temperature, the resistivity drops steeply in the case of NbO _x , but remains steady or rises somewhat in the case of TiO _x and VO _x , depending on the exact value ofx. It is suggested that in TiO _x and VO _x there is a large resistivity component due to scattering of carriers by disordered vacancies. Superconductivity was observed in NbO _x (T _c=1.38 K,x=1.0) and TiO _x (T _c=1.0 K,x=1.07). In the latter case the material showed a well-defined maximum ofT _c as a function of composition, withT _c<0.05 K forx<0.85 andx>1.20. Several VO _x samples remained normal to 0.07 K.     

Attachment processes in the supervisory relationship: An exploratory investigation.

How do relational characteristics of clinical trainees and supervisors influence the supervisory relationship? Following suggestions that attachment theory might shed light on this question, the authors asked doctoral-level psychology interns (N = 87) to complete an online survey about attachment processes and supervision experiences. Findings indicated that perceived supervisor attachment style was significantly associated with supervision task and bond. Regardless of their own attachment style, participants reporting secure supervisors rated the supervisory bond higher than participants reporting insecure supervisors. Results of path analyses suggested that parental indifference, compulsive self-reliance, and perceived supervisor attachment style may be particularly important in shaping the supervisory alliance. Implications for training and supervision are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specific heat of para-hydrogen monolayers on graphite

The specific heat of para-hydrogen films has been measured from 1 to 20 K for areal densities between 0.01 and 0.055 atoms/Å ² of the partial monolayer adsorbed on grafoil. The results are compared with the specific heat of ⁴ He films at equivalent densities. It is argued that a nonideal gas regime and liquefaction are present in both systems and that solidification of thep-H ₂ films has been suppressed to below the temperature range of the experiment. Implications regarding 2D superfluidity in hydrogen monolayers are discussed briefly.     

Influence of absorbed moisture on fatigue crack propagation behaviour in polyamides

The fatigue fracture surface morphology of nylon 66, nylon 6 and nylon 612 was examined to ascertain mechanisms of fatigue crack propagation (FCP) in these polymers. Attention was also given to noting any correlation between fracture surface markings and macroscopic fatigue crack-growth rate data. In general, observed changes in fracture surface appearance reflected an increasing level of plastic deformation with increasing water content, particularly in N66 and N6. Classical fatigue striations were identified in specimens of N66 and N6 containing 1.7 to 5.7 wt% water. Other types of fracture lineage of unknown origin were also seen which can confound the interpretation of fatigue fracture topography. Unlike the cases of N6 and N66, the fracture of N612 was dominated by a microvoid coalescence mechanism at all moisture levels and at all K levels examined.     

Oligodendrocytes secrete exosomes containing major myelin and stress-protective proteins: Trophic support for axons?

Oligodendrocytes synthesize the CNS myelin sheath by enwrapping axonal segments with elongations of their plasma membrane. Spatial and temporal control of membrane traffic is a prerequisite for proper myelin formation. The major myelin proteolipid protein (PLP) accumulates in late endosomal storage compartments and multivesicular bodies (MVBs). Fusion of MVBs with the plasma membrane results in the release of the intralumenal vesicles, termed exosomes, into the extracellular space. Here, we show that cultured oligodendrocytes secrete exosomes carrying major amounts of PLP and 2'3'-cyclic-nucleotide-phosphodiesterase (CNP). These exosomes migrated at the characteristic density of 1.10-1.14?g/mL in sucrose density gradients. Treatment of primary oligodendrocytes with the calcium-ionophore ionomycin markedly increased the release of PLP-containing exosomes, indicating that oligodendroglial exosome secretion is regulated by cytosolic calcium levels. A proteomic analysis of the exosomal fraction isolated by sucrose density centrifugation revealed in addition to PLP and CNP, myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) as constituents of oligodendroglial exosomes, together with a striking group of proteins with proposed functions in the relief of cell stress. Oligodendroglial exosome secretion may contribute to balanced production of myelin proteins and lipids, but in addition exosomes may embody a signaling moiety involved in glia-mediated trophic support to axons.     

An Exact Confidence Set for a Maximum Point of a Univariate Polynomial Function in a Given Interval

Construction of a confidence set for a maximum point of a function is an important statistical problem which has many applications. In this article, an exact 1 ? α confidence set is provided for a maximum point of a univariate polynomial function in a given interval. It is shown how the construction method can readily be applied to many parametric and semiparametric regression models involving a univariate polynomial function. Examples are given to illustrate this confidence set and to demonstrate that it can be substantially narrower and so better than the only other confidence set available in the statistical literature that guarantees 1 ? α confidence level.     

Influence of Salt Concentration and Nitrogen Source on Growth and Productivity of Anaerobiosprillum succiniciproducens

The influence of salts and organic nitrogen sources on the growth and acid production of Anaerobiosprillum succiniciproducens was studied. In shake flask experiments, maximum specific growth rate and acid production increased by reducing the salt concentration. Additionally, growth and acid production were affected by the type of organic nitrogen source and by the pH value. Through the optimization, optical density could be increased from 1.9 ± 0.1 to 3.0 ± 0.1 and succinic acid concentration from 4.0 ± 0.2 to 6.5 ± 0.1 g L^–1. In fed‐batch experiments with the optimized medium, the final succinic acid concentration was 25.6 % higher compared to the reference. Also, the succinic acid/acetic acid ratio was affected by the optimization. The experimental results indicated that A. succiniciproducens consumed only organic nitrogen sources because growth and productivity were not influenced by the addition of ammonium sulfate.