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Kompozyt Al(Mg)-NiO wytworzono metodą mechanicznej syntezy stosując mielenie składników proszkowych i mechaniczną konsolidację uzyskanego proszku kompozytowego w procesie prasowania próżniowego i wyciskania „na gorąco”. Uzyskano jednorodny materiał charakteryzujący się dużym rozdrobnieniem składników strukturalnych. Próby ściskania w temperaturze 293 K - 773 K wykazały wysokie własności mechaniczne kompozytu. Wyżarzanie próbek w 823 K / 6 godz. spowodowało nieznaczne obniżenie wartości naprężenia uplastyczniającego w zakresie 573 K - 773 K, jednakże w znacznie mniejszym stopniu niż w porównywanym przypadku kompozytu nie zawierającego dodatku magnezu (Al-NiO). który opisano we wcześniejszej pracy. Obserwacje struktury wyjściowych próbek kompozytowych i próbek wyżarzonych w 823 K / 6 godz. wykazały zmiany strukturalne wywołane reakcją chemiczną między osnową kompozytu (Al-Mg) a dyspersyjnymi cząstkami zbrojenia (NiO), której skutkiem jest utworzenie silnie dyspersyjnych wydzieleń tlenków typu spinelu, oraz submikronowych ziarn typu Al3Ni. W porównaniu z kompozytem Al-NiO, dodatek magnezu powoduje zwiększenie szybkości reakcji chemicznej, która przejawia się utworzeniem ziarn fazy międzymetalicznej Al3Ni zarówno w materiale wyjściowym - wyciskanym „na gorąco” - jak również w próbkach wyżarzonych w 823 K / 6 godz.

Hot deformation tests were performed on an AA7039-matrix composite reinforced with a 20% addition of SiC whiskers. The flow stress maximum was reduced with deformation temperature from 640 MPa to ∼8 MPa at 293 K and 823 K, respectively. TEM observations, performed on as deformed samples, revealed a highly recovered substructure of the matrix and a striated structure of the whiskers. The fringes, which are perpendicular to the whiskers’ longitudinal axis, were ascribed to nano-sized twins and stacking faults formed during the crystal growth rather than to some effects of the deformation process. [ABSTRACT FROM AUTHOR]

Mechanical alloying and hot extrusion method were used for manufacturing AlMg-based composites reinforced with addition of niobium oxide (Nb2O5) and zirconium silicide (ZrSi2) particles. High mechanical properties of the materials were found to result from heavily refined structure of composites. It was found that the composite structure was transformed at high temperature as a result of irreversible chemical reaction between disperse reinforcements and surrounding matrix. Chemical reaction for AlMg–Nb2O5 composite results in a growth of intermetallic grains of Al3Nb type and very fine oxides particles of 5–20 nm in diameter. In the annealed AlMg–ZrSi2 composite, new grains of Al3Zr, Mg2Si and Al(Mg)O are formed as a result of zirconium silicide decomposition. Hot compression tests were performed at constant true strain rate of 5.10−3 s−1 within the temperature range of 293–823 K. The high flow stress values are attributed to highly refined structure of the materials that essentially did not coarsen in spite of high deformation temperature. [ABSTRACT FROM AUTHOR]

In order to conduct fast screening of passengers with infections such as severe acute respiratory syndrome (SARS) or pandemic influenza at a quarantine depot, we developed a non-contact screening system with self-produced program to conduct a human screening within five seconds, via a linear discriminant function from non-contact derived variables, i.e. palmer pulse derived from a laser Doppler blood-flow meter, respiration rate determined by a 10-GHz microwave radar, and facial temperature measured by thermography. The system evaluation was conducted on seven healthy male subjects (23 ± 1 years). In order to achieve a pseudo-infection condition, the subjects maintained an ergo-meter exercise load (100 W, 10 minutes). Before (normal condition) and after (pseudo-infection condition) exercise, a significant linear discriminant function (p < 0.001) was determined to distinguish pseudo-infection condition from normal condition (Mahalanobis D-square = 20.3, classification error rate <5%). The proposed system appears promising for future application in fast screening of infection at a quarantine depot. [ABSTRACT FROM AUTHOR]

A mechanical alloying and hot extrusion method was used to manufacture an Al based composite reinforced by 10 wt-% addition of Nb2O5. Annealing experiments were performed to test the effect of chemical reaction between components on the material structure. After annealing at 873 K for 12 h the material hardness was found to have increased from HB 121 (as extruded) to HB 186 (annealed). The hardness maximum was followed by material softening at prolonged aging at 873 K. Transmission electron microscopy observations revealed a very well consolidated nanoscale structure for the as extruded composite. Annealing of the material resulted in an increase in porosity that was ascribed to Nb oxide reduction by aluminium. Due to diffusion of the released Nb element into the surrounding Al matrix, formation of new intermetallic grains of Al3Nb was accompanied by very fine needlelike Al oxide particle growth within the aluminium matrix. Chemical reaction between aluminium and Nb oxide at solid state was related to local specific volume reduction being responsible for an increase in the material porosity. Hot compression tests were performed on as extruded and samples annealed at 873 K for 12 h. The good mechanical properties of the composite were ascribed to the highly refined structure of the material. In compression tests, samples were not fractured within the experimental strain range used. In hot deformation tests at lower temperatures and a strain rate of 5 10-3 s-1, some fine microcavities were observed by TEM for samples deformed to ℇt≈0·3. [ABSTRACT FROM AUTHOR]

Structural observations and hot deformation tests were carried out on mechanically alloyed Al-10 wt-%V2 O5 composite. Initial annealing experiments revealed a hardening of the material during the first stage of annealing. The material hardness increased from 114 HB for as extruded material to 167 HB after annealing at 873 K for 6 h. Differential scanning calorimetry tests conducted on as extruded material confirmed the development of an exothermic reaction during heating of the material within the temperature range 650–870 K. The amount of heat released was reduced with increasing annealing time at 873 K. Transmission electron microscopy (TEM) and X-ray analysis of annealed material revealed new intermetallic grains and very fine aluminium oxide particles, which resulted from the chemical reaction between the aluminium matrix and vanadium oxides. The development of voids in long aged specimens was found to be an undesirable effect of local specific volume reduction during the course of the chemical reaction that was not fully compensated by the local volume increase due to the growth of intermetallic particles. As a result, the material hardness was reduced in long time annealed specimens. The mechanical properties of as extruded and annealed specimens were investigated by means of hot compression testing within the temperature range 623–903 K. These tests revealed that the flow stress of as extruded material was reduced from 180 to 22 MPa when tested at 623 and 903 K, respectively. Annealed specimens exhibited higher flow stresses of 195 and 32 MPa at the same temperatures. The results indicate that the strength of the material can be effectively increased owing to a change of material structure as a result of the chemical reaction taking place during high temperature annealing. [ABSTRACT FROM AUTHOR]

Background: Many investigations of the relationship between ulcerative colitis (UC) and heat-shock protein (Hsp) 60 have been reported. We have already established an animal model exhibiting UC-like lesions caused by administration of Escherichia coli expressing Yersinia enterocolitica Hsp60. In this study, we therefore attempted to induce mouse colitis by purified Y. enterocolitica Hsp60. Methods: Purified Y. enterocolitica Hsp60 was injected intraperitoneally into B10A/SgSn mice at a dose of 3 μg/0.2 ml once a week for 2 months, and morphological changes in the intestine were examined by light and electron microscopical analysis. Autoimmune responses were also examined. Results: The mice treated with Y. enterocolitica Hsp60 exhibited immune reaction between large intestine and autologous serum. Light and electron microscopically, degradation of glandular ducts, erosions, ulceration, crypt abscess-like formation, infiltration of inflammatory cells and absence of perivascular reticular fibers in lamina propria mucosae and subepithelial reticular layer were observed. Conclusions: These findings indicate that administration of Y. enterocolitica Hsp60 induces UC-like lesions with autoimmune responses. [ABSTRACT FROM AUTHOR]

It has been found that hypophysectomy protects aflatoxin B1 (AFB1) hepatocarcinogenesis and the prevention of apoptosis is a critical process for tumorigenesis. In this paper, we analyzed the cell death of AFB1-induced rat hepatoma Kagura-2 (K2) cells elicited by an estrogen antagonist, tamoxifen (TAM), and transforming growth factor-β1 (TGF-β1) to elucidate the function of endocrine factors in AFB1 hepatocarcinogenesis. TAM and TGF-β1 induced a typical apoptosis in K2 cells. The apoptotic cell death was efficiently suppressed by glucocorticoids (GCs), but not by other steroid compounds including 17β-estradiol (E2). Cyclo-oxygenase (COX) inhibitors such as aspirin (ASP) and indomethacin (IND) also inhibited the apoptosis, while inhibitory effects of general lipoxygenase (LOX) inhibitors such as nordihydroguaiaretic acid (NDGA) and 5,8,11-eicosatrienoic acid (ETI) were not observed. TAM and TGF-β1 enhanced the release of [3H]arachidonic acid (AA) from pre-labeled K2 cells, which was inhibited by dexamethasone (DEX). Furthermore, cytosolic phospholipase A2 (cPLA2) activity in K2 cells treated with TAM for 2 h was higher than that in the control. Prostaglandin J2 (PGJ2) and Δ12-PGJ2, AA metabolites formed in the COX pathway, induced K2 cell death. These results suggest that AA metabolites are involved in apoptotic K2 cell death elicited by TAM and TGF-β1 , and GCs could act as a tumor promoter in AFB1 hepatocarcinogenesis through the prevention of apoptosis induced by AA metabolites formed in vivo. [ABSTRACT FROM PUBLISHER]

In patients with inflammatory bowel disease (IBD), including ulcerative colitis (UC), heat-shock protein (Hsp) 60 has been detected in serum and the intestinal tract. Our mouse colitis model was established using Escherichia coli transformed with Yersinia enterocolitica Hsp60 gene as an immunizing antigen, and examined light and electron microscopically as compared with lesions of UC. The large intestine of mice injected with Hsp60 antigen showed swollen goblet cells, glandular dilation, erosion, ulceration, and infiltration of inflammatory cells. The change like crypt abscesses was also found, and various phases of inflammation were observed simultaneously in individual mice. In addition, the reticulum fibers were absent ultrastructurally in the subepithelial reticular layer. Hyperplasia of the thymus was found in antigen-treated mice. These lesions were similar to those of UC. These results suggest that UC-like enteritis in mice was induced by using Hsp60, considered as one of the pathogens for UC. [ABSTRACT FROM AUTHOR]