Rapid solidification of Ni3Al by Osprey deposition

A Ni3Al-based alloy containing Cr is examined after preparation by Osprey deposition. The microstructure consists of solidified spherical regions showing cellular segregation interspersed with regions of finer, equiaxed segregation morphology. The segregation structure is characterized by cell interiors rich in aluminum and poor in chromium, while the cell walls are poor in aluminum and rich in chromium. This segregation pattern is the inverse of that expected, based on earlier melt spinning experience, and is explained in terms of the undercooling of the melt prior to solidification. Very high temperature annealing is required to homogenize the material, despite the use of this rapid solidification process for material fabricatio

Experimental study of laboratory-heated CM2 chondrites Mighei and Murchison

We conducted experimental heating of two CM2 chondrites, Murchison and Mighei, to study changes in their oxygen isotopic compositions and mineralogy and explore possible genetic relationships between MCCs and normal CMs

Fermionic and Bosonic Stabilizing Effects for Type I and Type II Dimension Bubbles

We consider two types of "dimension bubbles", which are viewed as 4d nontopological solitons that emerge from a 5d theory with a compact extra dimension. The size of the extra dimension varies rapidly within the domain wall of the soliton. We consider the cases of type I (II) bubbles where the size of the extra dimension inside the bubble is much larger (smaller) than outside. Type I bubbles with thin domain walls can be stabilized by the entrapment of various particle modes whose masses become much smaller inside than outside the bubble. This is demonstrated here for the cases of scalar bosons, fermions, and massive vector bosons, including both Kaluza-Klein zero modes and Kaluza-Klein excitation modes. Type II bubbles expel massive particle modes but both types can be stabilized by photons. Plasma filled bubbles containing a variety of massless or nearly massless radiation modes may exist as long-lived metastable states. Furthermore, in contrast to the case with a "gravitational bag", the metric for a fluid-filled dimension bubble does not exhibit a naked singularity at the bubble's center.Comment: 17 pages, no figs; to appear in Phys.Rev.

Domain Bubbles of Extra Dimensions

``Dimension bubbles'' of the type previously studied by Blau and Guendelman [S.K. Blau and E.I. Guendelman, Phys. Rev. D40, 1909 (1989)], which effectively enclose a region of 5d spacetime and are surrounded by a region of 4d spacetime, can arise in a 5d theory with a compact extra dimension that is dimensionally reduced to give an effective 4d theory. These bubbles with thin domain walls can be stabilized against total collapse in a rather natural way by a scalar field which, as in the case with ``ordinary'' nontopological solitons, traps light scalar particles inside the bubble.Comment: 13 pages, no figures; to appear in Phys.Rev.

Gauged Dimension Bubbles

Some of the peculiar electrodynamical effects associated with gauged ``dimension bubbles'' are presented. Such bubbles, which effectively enclose a region of 5d spacetime, can arise from a 5d theory with a compact extra dimension. Bubbles with thin domain walls can be stabilized against total collapse by the entrapment of light charged scalar bosons inside the bubble, extending the idea of a neutral dimension bubble to accommodate the case of a gauged U(1) symmetry. Using a dielectric approach to the 4d dilaton-Maxwell theory, it is seen that the bubble wall is almost totally opaque to photons, leading to a new stabilization mechanism due to trapped photons. Photon dominated bubbles very slowly shrink, resulting in a temperature increase inside the bubble. At some critical temperature, however, these bubbles explode, with a release of radiation.Comment: 14 pages, no figures; to appear in Phys.Rev.

PC Based Display for Sonar Applications: A Design Experience

An attempt was made to standardise the hardware and the software used for the sonar display systems. The idea of standardise hardware suggested itself in using an IBM-compatible PC AT which configures with an Intel 80386 CPU and a standard VGA display adapter card. The software consists of Intel assembly procedures embedded in a PASCAL (turbo 4.0) environment

Sample convection in liquid-state NMR: Why it is always with us, and what we can do about it

AbstractMany NMR experiments on liquids suffer if the sample convects. This is particularly true for applications, such as the measurement of diffusion, that rely on spatial labelling of spins. It is widely assumed that, in most well-conducted experiments with stable temperature regulation, samples do not convect. Unfortunately this is not the case. It is shown here that typical NMR samples show measurable convective flow for all but a very narrow range of temperatures; convection is seen both above and below this range, which can be as small as a degree or so for a mobile solvent such as chloroform. This convection is driven by both vertical and horizontal temperature gradients.Measurements of convection velocity are presented for a range of samples, sample tubes, probes, and temperatures. Both decreasing sample tube inner diameter and changing sample tube material from glass to sapphire can slow convection markedly, with sapphire tubes being particularly effective. Such tubes are likely to be particularly helpful for accurate measurement of diffusion by NMR

Involution of the mouse mammary gland is associated with an immune cascade and an acute-phase response, involving LBP, CD14 and STAT3

INTRODUCTION: Involution of the mammary gland is a complex process of controlled apoptosis and tissue remodelling. The aim of the project was to identify genes that are specifically involved in this process. METHODS: We used Affymetrix oligonucleotide microarrays to perform a detailed transcript analysis on the mechanism of controlled involution after withdrawal of the pups at day seven of lactation. Some of the results were confirmed by semi-quantitative reverse transcriptase polymerase chain reaction, Western blotting or immunohistochemistry. RESULTS: We identified 145 genes that were specifically upregulated during the first 4 days of involution; of these, 49 encoded immunoglobulin genes. A further 12 genes, including those encoding the signal transducer and activator of transcription 3 (STAT3), the lipopolysaccharide receptor (CD14) and lipopolysaccharide-binding protein (LBP), were involved in the acute-phase response, demonstrating that the expression of acute-phase response genes can occur in the mammary gland itself and not only in the liver. Expression of LBP and CD14 was upregulated, at both the RNA and protein level, immediately after pup withdrawal; CD14 was strongly expressed in the luminal epithelial cells. Other genes identified suggested neutrophil activation early in involution, followed by macrophage activation late in the process. Immunohistochemistry and histological staining confirmed the infiltration of the involuting mammary tissue with neutrophils, plasma cells, macrophages and eosinophils. CONCLUSION: Oligonucleotide microarrays are a useful tool for identifying genes that are involved in the complex developmental process of mammary gland involution. The genes identified are consistent with an immune cascade, with an early acute-phase response that occurs in the mammary gland itself and resembles a wound healing process

Izvori za epjdem10loško proučavanje zdravstvenlh efekata gasifikacije uglja

An occupational population is characterized as a basis for epidemiological study. Parameters include age, smoking history, years of work, job title, all medical diagnoses by 3-digit ICD code, and selected Iaboratory test results. By example analyses differences are examined in the incidence of chrome bronchitis and circulatory system disease by smoking history and job title. The data base includes coal gasification plant workers and surface lignite minors in Kosovo, Yugoslavia. Because of the national system of socialized medicine, similar data are available for all worker organizations in Yugoslavia.Analiza zaposlenih radnika služila je kao osnova epidemiološkog proučavania. Praćeni parametri obuhvatih su dob, naviku pušenja, radno rnesto i sve lekarske dijagnoze prema trocifrenoj internacionalnoj kodifikaciji bolesti, kao i određene laboratorijske rezultate. Dat je primer proučavanja razlika incidence hroničnog bronhita i bolesti cirkulatornog sistema prema navici pušenja i radnom mestu. Podaci se odnose na radnike gasifikacije uglja i rudnika površinskog kopa u Kosovskorn bazenu. S obzirom na zdravstvenu zaštitu i unificirani sistem, slične informacije se mogu dobiti za sve radne organizacije u Jugoslaviji

Proučavanje rane pojave tumora kod radnika gasifikacije uglja

A retrospective cohort morbidity study was conducted among workers employed at the Kosovo coal gasification plant and a reference population of open-pit lignite miners. The aim was to determine the rate of early skin cancer and pre-cancerous skin lesions. In 15 years of commercial operation of the coal gasification plant, seven workers were diagnosed with benign skin tumors, six with pre-cancerous skin diseases, but none with skin cancer. The lesions were significantly fewer than were reported earlier over a shorter time period and in a smaller population at a coal hydrogenation plant. Compared to the reference population who received medical care in the same clinic, gasification workers had a lower skin cancer rate, but a higher rate of benign skin turners and potentially pre-cancerous skin diseases.Kod radnika zapošljenih na gasifikaciji uglja obavljena su proučavanja morbiditeta i nalazi su uspoređeni s nalazima kod rudara lignita. Svrha ove analize sastojala se u proučavanju da li se kod radnika gasifikacije uglja pojavljuje visoki procenat ranog ispoljavanja raka kože i prekanceroznih lezija sličnih onim opaženim kod radnika zapošljenih na hidrogenizaciji uglja. U toku 15 godina komercijalnog rada postrojenja za gasifikaciju uglja utvrđeni su kod sedam radnika benigni tumori kože, kod šest radnika prekancerozno stanje kože, a ni kod jednog od njih nije nađen karcinom kože. Učestalost ovih poremećaja bila je znatno manja nego kod manje grupe radnika koji su radili kraći vremenski period na hidrogenizaciji uglja. Broj malignih poremećaja bio je znatno niži, ali benigni tumori kože i potencijalne prekancerozne promene koje bile su nađene kod većeg procenta u radnika gasifikacije uglja nego u komparativnoj grupi rudara sa otvorenog kopa lignita, koji su inače praćeni u istoj zdravstvenoj ustanovi