Formation of Nanocrystalline Solid Solution in Al-Fe-V-Si Alloys by Mechanical Alloying

In this study, the microstructural evolution of Al-Fe-V-Si alloy prepared by mechanical alloying starting from elemental powders was studied. X-ray diffraction results showed that by increasing the milling time, peak shifting and peak broadening of Al reflections occur due to dissolution of alloying elements and grain refinement, respectively. Reduction of Al lattice parameter by increasing the milling time indicates that an Al based solid solutions formed during mechanical alloying and solute concentration increased by increasing the milling time. After 60 h of milling, the microstructure consisted of a nanocrystalline Al solid solutions with a grain size of 19 nm and an internal strain of 0.55 in which Si phase was dispersed. In contrast to previous studies on rapidly solidified Al-Fe-V-Si alloys, there is no formation of trace of Al12(Fe,V)3Si or other intermetallic compounds in the as-milled condition. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3509

Histochemical Localization of Phosphatases in the Stable Fly, Stomoxys Calcitrans (L.), Using Naphthol As-Phoshate

Author Institution: Department of Zoology and Entomology, The Ohio State University, Columbus 1

Rosemary wilting disease and its management by soil solarization technique in Iran

Wilting disease on Rosemary (Rosmarinus officinalis), an ornamental-medical plant, was studied from 2007 - 2009 in Mashhad, north-east Iran. Different Rosemary fields in this area were visited and root samples of the infected plants and soil around the roots were collected and transferred to laboratory. Samples were cultured on CMA, PDA and WA media and isolated fungi were identified. Three fungal pathogens including Phytophthora citrophthora, Rhizoctonia solani and Fusarium oxysporum were determined, whereas Helicotylenchus spp. was also associated. Pathogenicity tests proved that they were wilting pathogens, although P. citrophthora was the major pathogen in the field and glasshouses. This is the first report on Rosemary disease in the  country. The disease caused losses from 30 – 60% in the fields where the suitable conditions allowed the disease to build up. Soil solarization technique was carried out to control pathogens before planting of  seedlings. Application of this method reduced population density of P. citrophthora and F. oxysporum from  1300 - 1800 cfu –g/soil to 500 - 700 after 4 weeks and then 200 - 300 cfu (colony forming propagules) after 6  weeks. Solarization is a simple, economic and effective technique in managing Rosemary wilting disease  before plant planting in new established orchards.Key words: Rosemary, Phytophthora citophthora, wilting, Iran

Zinc Deficiency Produces Time-Related Ultrastructural Changes in Rat Cheek Epithelium

The subject of this study was whether the ultrastructural changes in cheek epithelium of zinc-deficient rats are time related. Weanling male Sprague Dawley rats were fed a zinc-deficient diet containing 0.4 ppm zinc (ZD) ad libitum and controls were pair-fed zinc adequate diet containing 40 ppm zinc. After 9, 18, and 27 days of zinc deficiency, specimens from cheek epithelium of both groups were processed for transmission electron microscopy. Partial conversion of the orthokeratinized cheek epithelium to parakeratinized was seen as early 9 days. An electron-lucent band surrounding the nucleus was observed in ZD cells. Mitochondria, tonofilaments, keratohyalin granules and ribosomes seemed to be increased with the increase in time of zinc deficiency. There was a thickening of the stratum corneum as well as hyperplasia and widening of the inter-cellular spaces of the spinous layer cells. Retention of a few membrane coating granules (MCGs) in the parakeratinized layer was seen after 9 days. Parakeratinization was further increased after 18 days of zinc deficiency, and the number of MCG profiles also increased. The epithelium was fully parakeratinized following 27 days of zinc deficiency, and the number of MCG profiles was increased. It was concluded that zinc deficiency affected cell proliferation and differentiation of the epithelium as early as 9 days, and caused a delay in loss of nuclei and MCGs in parakeratinized cells

Balaban Index of an Infinite Class of Dendrimers

The Balaban index of a graph G is the first simple index of very low degeneracy. It is defined as the sum of topological distances from a given atom to any other atoms in a molecule. In this paper the Balaban index of an infinite family of dendrimers is computed. The result can be of interest in molecular data mining, particularly in searching the uniqueness of tested (hyper-branched) molecular graphs

Simulation of Logging While Drilling Tools Based on Amorphous Si:H and LaBr3:Ce Detectors

Bore hole logging data represent the properties of rocks, such as porosity, density and constitutiveelements of formation, as a function of depth in a well. Properties of rocks are obtained from thermal neutron counting and gamma ray radiation due to neutron activation. Transport of neutrons, from an Am-Be source situated in a bore-hole tool, through rock media to detectors, has been simulated using a GEANT4 radiation transport code. The high precision GEANT4 cross section library was used to gain better analyses about well formation. In this paper we present the results of simulation of logging tools based on boron coated amorphous silicon detector for thermal neutron detection and LaBr3:Ce detector for gamma spectroscopy. Key words: Well logging; Spectroscopy; GEANT

Review

Mitochondria are the main suppliers of neuronal adenosine triphosphate and play a critical role in brain energy metabolism. Mitochondria also serve as Ca2+ sinks and anabolic factories and are therefore essential for neuronal function and survival. Dysregulation of neuronal bioenergetics is increasingly implicated in neurodegenerative disorders, particularly Parkinson's disease. This review describes the role of mitochondria in energy metabolism under resting conditions and during synaptic transmission, and presents evidence for the contribution of neuronal mitochondrial dysfunction to Parkinson's disease

Secretory Ameloblasts and Calcium Distribution During Normal and Experimentally Altered Mineralization

The distribution of calcium in relation to secretory ameloblasts of the rat incisor was studied. An experimental model system in which enamel mineralization was temporarily inhibited by injecting sodium fluoride and cobalt chloride was used. Potassium pyroantimonate (PPA) cytochemistry, electron energy loss spectroscopy (EELS), and energy dispersive X-ray spectrometry (EDS) were used to clarify the role of the ameloblast in controlling calcium distribution during normal and experimentally altered enamel mineralization. Secretory ameloblasts chemically-preserved in glutaraldehyde either with or without PPA were analyzed for calcium; those preserved with PPA showed higher concentrations of calcium than did those preserved with glutaraldehyde only. Freeze-dried control and experimental tissues showed an increasing gradient of calcium from stratum intermedium cells to the distal ends of the ameloblasts. Calcium levels were reduced near the distal ends of the cells following fluoride and cobalt injections, while magnesium levels were increased markedly in the same region. This multi-method approach showed correlated calcium localization in specific regions of this cell in relation to changes in function. The study thus provides additional evidence for active involvement of the ameloblasts in enamel mineralization