An influence of static load on fatigue life of parts under combined stress

The paper deals with a special case of multiaxial fatigue in a plain stress possessing one component static and the other dynamic. Exponents of Haigs' limit curves were obtained experimentally both for tensile fatigue test and combined tensile/torgue tests. Errors of estimated fatigue lives are less than 20 %

Pairing patterns and fitness in a free-ranging population of pinyon jays: What do they reveal about mate choice.

Pairing in 141 pairs of Pinyon Jays (Gymnorhinus cyanocephalus ) was assortative for age, but was random for bill length and body weight. Assortative pairing for age may be favored because similar-aged partners produced slightly more young than dissimilar-aged ones and their young survived longer than young from dissimilar-aged pairs. Large jays appear to have the highest genetic quality because they lived longer and body size was heritable. Genetic quality of a mate, however, may be negated if phenotypic properties of partners are not compatible

Electromiograph Study of Patients Treated with Overdentures Retined with Implants

INTRODUCTION: Long Term edentulous patients present severe bone loss in their alveolar ridges, as a consequence there is serious compromise in esthetics and function. A therapeutic alternative which we can offer to these patients is an overdenture retined with dental implants, in order to improve retention and stability. AIM OF THE WORK: The aim of the study was to determine by electromiography whether the muscular groups involved in masticatory function present any special activity in patients treated with overdentures retined with dental implants. MATERIAL AND METHODS: We selected ten complete edentulous patients with inferior overdentures retined with two implants and a bar.Myotronics K6-I with eight channels, and registration of anterior and posterior temporalis muscle maseter and dygastric muscles. We performed recordings in rest positions and maximum force bite. RESULTS AND CONCLUSION: The results obtained indicate an increase in activity in the rest position of the posterior temporalis group

The polarized expression of Na+,K+-ATPase in epithelia depends on the association between beta-subunits located in neighboring cells

The polarized distribution of Na+,K+-ATPase plays a paramount physiological role, because either directly or through coupling with co- and countertransporters, it is responsible for the net movement of, for example, glucose, amino acids, Ca2+, K+, Cl-, and CO3H- across the whole epithelium. We report here that the beta-subunit is a key factor in the polarized distribution of this enzyme. 1) Madin-Darby canine kidney (MDCK) cells (epithelial from dog kidney) express the Na+,K+-ATPase over the lateral side, but not on the basal and apical domains, as if the contact with a neighboring cell were crucial for the specific membrane location of this enzyme. 2) MDCK cells cocultured with other epithelial types (derived from human, cat, dog, pig, monkey, rabbit, mouse, hamster, and rat) express the enzyme in all (100%) homotypic MDCK/MDCK borders but rarely in heterotypic ones. 3) Although MDCK cells never express Na+,K+-ATPase at contacts with Chinese hamster ovary (CHO) cells, they do when CHO cells are transfected with beta(1)-subunit from the dog kidney (CHO-beta). 4) This may be attributed to the adhesive property of the beta(1)-subunit, because an aggregation assay using CHO (mock-transfected) and CHO-beta cells shows that the expression of dog beta(1)-subunit in the plasma membrane does increase adhesiveness. 5) This adhesiveness does not involve adherens or tight junctions. 6) Transfection of beta(1)-subunit forces CHO-beta cells to coexpress endogenous a-subunit. Together, our results indicate that MDCK cells express Na+,K+-ATPase at a given border provided the contacting cell expresses the dog P,-subunit. The cell-cell interaction thus established would suffice to account for the polarized expression and positioning of Na+,K+-ATPase in epithelial cells

Genetic and ampelographic identification of different grape varieties known as 'Tempranillo' in Rioja (Spain)

Research Note

Site-selective laser spectroscopy of Nd 3+ ions in 0.8CaSiO 3-0.2Ca 3(PO 4) 2 biocompatible eutectic glass-ceramics

In this work we report the influence of the crystallization stage of the host matrix on the spectroscopic properties of Nd3+ ions in biocompatible glass-ceramic eutectic rods of composition 0.8CaSiO3-0.2Ca3(PO4)2 doped with 1 and 2 wt% of Nd2O3. The samples were obtained by the laser floating zone technique at different growth rates between 50 and 500 mm/h. The microstructural analysis shows that a growth rate increase or a rod diameter decrease leads the system to a structural arrangement from three (two crystalline and one amorphous) to two phases (one crystalline and one amorphous). Electron backscattering diffraction analysis shows the presence of Ca2SiO4 and apatite-like crystalline phases. Site-selective laser spectroscopy in the 4I9/2¿4F3/2/4F5/2 transitions confirms that Nd3+ ions are incorporated in crystalline and amorphous phases in these glass-ceramic samples. In particular, the presence of Ca2SiO4 crystalline phase in the samples grown at low rates, which has an excellent in vitro bioactivity, can be unambiguously identified from the excitation spectra and lifetime measurements of the 4F3/2 state of Nd3+ ions

The effects of requiring different response strategies following caching in Clark’s nutcrackers (Nucifraga columbiana)

Clark’s nutcrackers use spatial memory to recover stored food in the field and have performed very well in laboratory tests of spatial memory. During the present experiment, two groups of nutcrackers cached seeds every 4 days. Following each cache session, the stay group was tested with seeds in their caches; the shift group found seeds in novel sites. The stay group performed accurately throughout the experiment, but the shift group gave no indication of being able to learn to avoid sites where they had stored seeds. These results suggest that although nutcrackers can learn to shift away from remembered locations during some memory experiments, they cannot learn to shift away from cache sites. This raises interesting questions about the relationship between task characteristics, response strategies, and memory

Dbl3 drives Cdc42 signaling at the apical margin to regulate junction position and apical differentiation

Epithelial cells develop morphologically characteristic apical domains that are bordered by tight junctions, the apical–lateral border. Cdc42 and its effector complex Par6–atypical protein kinase c (aPKC) regulate multiple steps during epithelial differentiation, but the mechanisms that mediate process-specific activation of Cdc42 to drive apical morphogenesis and activate the transition from junction formation to apical differentiation are poorly understood. Using a small interfering RNA screen, we identify Dbl3 as a guanine nucleotide exchange factor that is recruited by ezrin to the apical membrane, that is enriched at a marginal zone apical to tight junctions, and that drives spatially restricted Cdc42 activation, promoting apical differentiation. Dbl3 depletion did not affect junction formation but did affect epithelial morphogenesis and brush border formation. Conversely, expression of active Dbl3 drove process-specific activation of the Par6–aPKC pathway, stimulating the transition from junction formation to apical differentiation and domain expansion, as well as the positioning of tight junctions. Thus, Dbl3 drives Cdc42 signaling at the apical margin to regulate morphogenesis, apical–lateral border positioning, and apical differentiation

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Evaluation of an image-based algorithm for quantitativ