Crystal structure and electronic spectrum of InGaSe<Subscript>2</Subscript>

We report the synthesis and crystal growth of InGaSe₂. The crystals have been characterized by X-ray diffraction and InGaSe₂ has been shown to crystallize in tetragonal symmetry. Using first-principles density functional theory (DFT) calculations, we have found optimized lattice parameters and equilibrium atomic position coordinates of the compound semiconductor InGaSe₂. Based on the optimization results, we have calculated the band structure and the total and projected densities of states in InGaSe₂, found out the origin of its conduction and valence bands, and determined its band gap. Using the partial densities of states of its constituent atoms, we have evaluated the nature of the chemical bonding in InGaSe₂.     

Glenohumeral instability: evaluation with MR arthrography

Magnetic resonance arthrography is superior to other imaging techniques in evaluation of the glenohumeral joint. Normal variants that can be diagnostic pitfalls include the anterosuperior sublabral foramen, the Buford complex, and hyaline cartilage under the labrum. Anteroinferior dislocation is the most frequent cause of anterior glenohumeral instability and produces a constellation of lesions (anteroinferior labral tear, classic and osseous Bankart lesions, Hill-Sachs lesion). Variants of anteroinferior labral tears include anterior labroligamentous periosteal sleeve avulsion and glenoid labral articular disruption. Anterior glenohumeral instability can also involve tears of the anterior or anterosuperior labrum or the glenohumeral ligaments. Posterior glenohumeral instability can involve a posterior labral tear, posterior capsular stripping or laxity; fracture, erosion, or sclerosis and ectopic ossification of the posterior glenoid fossa; reverse Hill-Sachs lesion; McLaughlin fracture; or posterosuperior glenoid impingement. Superior labral anterior and posterior lesions involve the superior labrum with varying degrees of biceps tendon involvement.     

Pediatric elbow fractures: MRI evaluation

Standard anatomy textbooks describe the mandibular canal as having a consistent, standard path. The fact that variations in its path exist in a significant percentage of the population is of extreme importance for the surgeon who is performing procedures in close proximity to the mandibular canal. A rare, radiographically detectable variation of the standard anatomy of the mandibular canal is reported.     

Immunolocalization of 11beta-hydroxysteroid dehydrogenase types 1 and 2 in rat uterus: variation across the estrous cycle and regulation by estrogen and progesterone

Glucocorticoid hormone action in several target tissues is dependent not only on the expression of the glucocorticoid receptor, but also on that of the 11beta-hydroxysteroid dehydrogenase (11betaHSD) enzymes, 11betaHSD-1 and -2. In the uterus, glucocorticoids can exert inhibitory effects on a range of important functions, particularly in relation to the effects of estrogen. Therefore, the present study examined immunolocalization of the two 11betaHSD enzymes in the rat uterus at each stage of the estrous cycle and after ovariectomy with or without estrogen/progesterone replacement. In cycling rats 11betaHSD-1 was localized to luminal and glandular epithelial cells and to eosinophils in both the endometrial stroma and myometrium. In contrast, 11betaHSD-2 immunostaining was localized to endometrial stromal cells and myometrial cells, with no staining evident in epithelial cells or eosinophils. Immunostaining for both enzymes was cycle dependent, being maximal at proestrus and minimal at diestrus. Western blot analysis of whole uterus at proestrus showed the presence of 34- and 40-kDa immunoreactive species for 11betaHSD-1 and -2, respectively. These immunoreactive signals were almost abolished by ovariectomy, but this effect was reversed for both enzymes by estrogen replacement with or without progesterone. These effects of ovariectomy and steroid replacement were confirmed by immunocytochemical analysis, with the exception that progesterone appeared to enhance the stimulatory effects of estrogen on 11betaHSD-2 specifically within the endometrial stroma. In conclusion, these results establish the presence of both 11betaHSD-1 and -2 in the nonpregnant rat uterus and show distinct distributions for the two enzymes and cyclic variation related to positive regulation by ovarian steroids. The physiological implications of these patterns of 11betaHSD expression will ultimately depend on the reaction direction for each enzyme, but 11betaHSD-2 is likely to limit disruptive effects of glucocorticoids on the endometrial stroma, and 11betaHSD-1 may then serve to selectively reactivate glucocorticoids in epithelial cells.     

The effect of the increase in the calcium concentration induced by action of the ionophore A-23187 on mitosis in cultured ESK cells

After addition of 20 mM calcium ionophore A23187 to cultured PK (pig kidney embryo) cells, [Ca++] in cytosol increased by more than 10 times. The maximum [Ca++] concentration was observed 1-2 min after drug introduction. Later on [Ca++] gradually decreased, and after 30 min of incubation with A23187 [Ca++] its concentration was 3-5 times higher than in the norm. 1 min after introduction of the calcium ionophore, mitotic spindles shortened for 1/3 and the angle of divergence of spindle microtubules from the centrosome extended. These changes remained for 5 min of treatment. After nocodazole treatment the length of the mitotic spindle reduced (2 min), then mitotic spindle and the metaphase plate were disrupted. The rate of mitotic spindle shortening after addition of the ionophore is about the same as after addition of nocodazole, but after ionophore treatment the metaphase plate remained for more than 5 min. Based on the results obtained we suggest that the maximum distance between spindle poles at metaphase is in the intact cell, and after any perturbation of normal microtubule dynamics the spindle may rapidly collapse. The collapsed mitotic spindle becomes more stable and its size is determined predominantly by kinetochore fibers. The metaphase spindle is completely and rapidly destroyed when the microtubule growth is prohibited, but it is preserved when this growth is restricted.     

Features of the electrodiffusion-plastic deformation of silicon

The effect of a change in the electron subsystem of a single crystal, caused by the electric-field-assisted transfer of impurity atoms, on the features of electroplastic deformation in silicon was studied. The new method of action upon the motion of dislocations revealed a considerable decrease in the yield point and an increase in the general plasticity as compared to those observed in the material deformed by traditional methods. Possible mechanisms explaining the observed effects are considered.     

Disorders of the cognitive functions in those who worked in the cleanup of the aftermath of the accident at the Chernobyl Atomic Electric Power Station

The potentialities of cerebral oximetry in the para-infrared band as a means of neuromonitoring are assessed. The method is highly informative for selecting the treatment strategy during the acute period of craniocerebral injury and cerebrovascular diseases. Simultaneous analysis of intracranial pressure, central hemodynamics, and cerebral oximetry permits differentiation of mechanisms of intracranial hypertension and its compensation. Increase of rSO2 in increased intracranial pressure corresponds to brain hyperemia, its decrease to cerebral ischemia. A long trend of rSO2 changes is informative for disease prediction.     

A differential response of two putative mammalian circadian regulators, mper1 and mper2, to light

A mouse gene, mper1, having all the properties expected of a circadian clock gene, was reported recently. This gene is expressed in a circadian pattern in the suprachiasmatic nucleus (SCN). mper1 maintains this pattern of circadian expression in constant darkness and can be entrained to a new light/dark cycle. Here we report the isolation of a second mammalian gene, mper2, which also has these properties and greater homology to Drosophila period. Expression of mper1 and mper2 is overlapping but asynchronous by 4 hr. mper1, unlike period and mper2, is expressed rapidly after exposure to light at CT22. It appears that mper1 is the pacemaker component which responds to light and thus mediates photic entrainment.