Chronic heat treatment causes skin wrinkle formation and oxidative damage in hairless mice

The aims of the present paper were to ascertain whether the heat-induced ischemia and oxidative damage to the hypothalamus and lethality in mice could be ameliorated by hyperbaric oxygen therapy. When normobaric air-treated mice underwent heat treatment, the fractional survival and core temperature at 4 hours after heat stress were found to be 0 of 12 and34∘C±0.3∘C, respectively. In hyperbaric oxygen-treated mice, when exposed to the same treatment, both fractional survival and core temperature values were significantly increased to new values of 12/12 and37.3∘C±0.3∘C, respectively. Compared to normobaric air-treated heatstroke mice, hyperbaric oxygen-treated mice displayed lower hypothalamic values of cellular ischemia and damage markers, prooxidant enzymes, proinflammatory cytokines, inducible nitric oxide synthase-dependent nitric oxide, and neuronal damage score. The data indicate that hyperbaric oxygen may improve outcomes of heatstroke by normalization of hypothalamic and thermoregulatory function in mice.

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Cyanidin-3-glucoside inhibits UVB-induced oxidative damage and inflammation by regulating MAP kinase and NF-κB signaling pathways in SKH-1 hairless mice skin

Toxicology and Applied Pharmacology ◽

10.1016/j.taap.2014.06.028 ◽

2014 ◽

Vol 280 (1) ◽

pp. 127-137 ◽

Cited By ~ 46

Author(s):

Poyil Pratheeshkumar ◽

Young-Ok Son ◽

Xin Wang ◽

Sasidharan Padmaja Divya ◽

Binoy Joseph ◽

...

Keyword(s):

Oxidative Damage ◽

Map Kinase ◽

Signaling Pathways ◽

Hairless Mice

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The Relevance of Photomutagenicity Testing as a Predictor of Photocarcinogenicity

International Journal of Toxicology ◽

10.1080/109158198226053 ◽

1998 ◽

Vol 17 (5) ◽

pp. 551-558 ◽

Cited By ~ 13

Author(s):

Lutz Müller ◽

Peter Kasper

Keyword(s):

Oxidative Damage ◽

Mammalian Cells ◽

Active Oxygen Species ◽

Gene Mutations ◽

Oxygen Species ◽

Chromosomal Damage ◽

Hairless Mice ◽

Molecular Events ◽

Repair Mechanisms

Today's lifestyle is associated with frequent and intense exposure to ultraviolet radiation (UVR). The tumorigenic effects of UVR are well known. Specifically, the premutagenic lesions of UVB (290-320 nm) are known to be the most important molecular events in UVR tumorigenicity. The less carcinogenic UVA (320-400 nm) mainly generates oxidative damage in the DNA via photody-namic generation of active oxygen species involving endogenous or exogenous photosen sitizers. Several pharmaceuticals are known to act as photosensitizers. Photoinstable phenothiazines, furocoumarins, and fluoroquinolones were shown to be very efficient inducers of chromosomal damage in mammalian cells in culture. Photocar cinogenicity testing in hairless mice of furocoumarins and several fluoroquinolones demonstrated a higher incidence and a shorter latent period for skin tumors compared to UVR alone. These data show a good correlation between the photomutagenic and photocarcinogenic potential of these compounds. Although mammalian cells possess effective repair mechanisms for oxidative damage, photoproducts, and dimers, these repair mechanisms can be overloaded. Eventually, unrepaired damage leads to gene mutations or chromosomal damage in exposed cells and to tumors in the skin. Therefore, in vitro photomutageni-city testing in mammalian cells may be an early and easy-to-measure predictor of the photocarcinogenic potential of a pharmaceutical.

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The Precipitation of Si in AlCuSi Thin Films

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070618 ◽

1973 ◽

Vol 31 ◽

pp. 34-35 ◽

Cited By ~ 1

Author(s):

R. M. Anderson

Keyword(s):

Electron Microscopy ◽

Thin Films ◽

Heat Treatment ◽

Solid Solution ◽

Integrated Circuit ◽

Copper Film ◽

Solution Concentration ◽

X Ray ◽

Silicon Thin Films ◽

Before And After

Aluminum-copper-silicon thin films have been considered as an interconnection metallurgy for integrated circuit applications. Various schemes have been proposed to incorporate small percent-ages of silicon into films that typically contain two to five percent copper. We undertook a study of the total effect of silicon on the aluminum copper film as revealed by transmission electron microscopy, scanning electron microscopy, x-ray diffraction and ion microprobe techniques as a function of the various deposition methods.X-ray investigations noted a change in solid solution concentration as a function of Si content before and after heat-treatment. The amount of solid solution in the Al increased with heat-treatment for films with ≥2% silicon and decreased for films <2% silicon.

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Erythrophagocytosis in the Liver in Hemolytic Anemias

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100100664 ◽

1968 ◽

Vol 26 ◽

pp. 184-185

Author(s):

O. T. Minick ◽

E. Orfei ◽

F. Volini ◽

G. Kent

Keyword(s):

Acid Phosphatase ◽

Oxidative Damage ◽

Phosphatase Activity ◽

Kupffer Cells ◽

Acid Phosphatase Activity ◽

Common Type ◽

Red Cell ◽

Cell Fragments ◽

Reticulo Endothelial System ◽

Important Site

Hemolytic anemias were produced in rats by administering phenylhydrazine or anti-erythrocytic (rooster) serum, the latter having agglutinin and hemolysin titers exceeding 1:1000.Following administration of phenylhydrazine, the erythrocytes undergo oxidative damage and are removed from the circulation by the cells of the reticulo-endothelial system, predominantly by the spleen. With increasing dosage or if animals are splenectomized, the Kupffer cells become an important site of sequestration and are greatly hypertrophied. Whole red cells are the most common type engulfed; they are broken down in digestive vacuoles, as shown by the presence of acid phosphatase activity (Fig. 1). Heinz body material and membranes persist longer than native hemoglobin. With larger doses of phenylhydrazine, erythrocytes undergo intravascular fragmentation, and the particles phagocytized are now mainly red cell fragments of varying sizes (Fig. 2).

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The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100105771 ◽

1988 ◽

Vol 46 ◽

pp. 742-743

Author(s):

E. Bischoff ◽

O. Sbaizero

Keyword(s):

Heat Treatment ◽

Aluminum Silicate ◽

Lithium Aluminum ◽

Interfacial Region ◽

Specimen Preparation ◽

Crack Wake ◽

Pull Out ◽

Annealed Material ◽

Ultrasonic Drilling ◽

Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

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Strain-induced martensite effects on transgranular carbide precipitation in type 304 stainless steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100087331 ◽

1991 ◽

Vol 49 ◽

pp. 604-605

Author(s):

A.H. Advani ◽

L.E. Murr ◽

D. Matlock

Keyword(s):

Heat Treatment ◽

Grain Boundary ◽

Stress Corrosion Cracking ◽

Stainless Steels ◽

Deformation Twin ◽

Austenitic Stainless Steels ◽

Carbide Precipitation ◽

Strain Induced Martensite ◽

Type 304

Thermomechanically induced strain is a key variable producing accelerated carbide precipitation, sensitization and stress corrosion cracking in austenitic stainless steels (SS). Recent work has indicated that higher levels of strain (above 20%) also produce transgranular (TG) carbide precipitation and corrosion simultaneous with the grain boundary phenomenon in 316 SS. Transgranular precipitates were noted to form primarily on deformation twin-fault planes and their intersections in 316 SS.Briant has indicated that TG precipitation in 316 SS is significantly different from 304 SS due to the formation of strain-induced martensite on 304 SS, though an understanding of the role of martensite on the process has not been developed. This study is concerned with evaluating the effects of strain and strain-induced martensite on TG carbide precipitation in 304 SS. The study was performed on samples of a 0.051%C-304 SS deformed to 33% followed by heat treatment at 670°C for 1 h.

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Effect of a Complex Heat Treatment on the Structure of 300M Steel

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100098071 ◽

1981 ◽

Vol 39 ◽

pp. 312-313

Author(s):

R. Padmanabhan ◽

W. E. Wood

Keyword(s):

Heat Treatment ◽

Metal Carbides ◽

Austenite Grain Size ◽

300M Steel ◽

Heat Treated ◽

Strain Fracture ◽

Prior Austenite Grain Size ◽

Short Time ◽

Final Tempering ◽

Similar Yield

Intermediate high temperature tempering prior to subsequent reaustenitization has been shown to double the plane strain fracture toughness as compared to conventionally heat treated UHSLA steels, at similar yield strength levels. The precipitation (during tempering) of metal carbides and their subsequent partial redissolution and refinement (during reaustenitization), in addition to the reduction in the prior austenite grain size during the cycling operation have all been suggested to contribute to the observed improvement in the mechanical properties. In this investigation, 300M steel was initially austenitized at 1143°K and then subjected to intermediate tempering at 923°K for 1 hr. before reaustenitizing at 1123°K for a short time and final tempering at 583°K. The changes in the microstructure responsible for the improvement in the properties have been studied and compared with conventionally heat treated steel. Fig. 1 shows interlath films of retained austenite produced during conventionally heat treatment.

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Crystallization of MgO • Al2 • SiO2 • ZrO2 glasses

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143778 ◽

1986 ◽

Vol 44 ◽

pp. 440-441

Author(s):

M. A. McCoy

Keyword(s):

Mechanical Properties ◽

Heat Treatment ◽

Powder Processing ◽

Glass Composition ◽

Ceramic Powder ◽

Transformation Toughening ◽

Ceramic Powder Processing ◽

Processing Techniques ◽

Ceramic Matrices

Transformation toughening by ZrO2 inclusions in various ceramic matrices has led to improved mechanical properties in these materials. Although the processing of these materials usually involves standard ceramic powder processing techniques, an alternate method of producing ZrO2 particles involves the devtrification of a ZrO2-containing glass. In this study the effects of glass composition (ZrO2 concentration) and heat treatment on the morphology of the crystallization products in a MgO•Al2•SiO2•ZrO2 glass was investigated.

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