Introduction: Secular trend of increasing musculoskeletal injuries (MSKIs) across all branches of the U.S. Military is a critical limiting factor in the effective and efficient process of preparing military personnel for combat.
View Article and Find Full Text PDFJ Geophys Res Planets
April 2021
The physical processes during planet formation span a large range of pressures and temperatures. Giant impacts, such as the one that formed the Moon, achieve peak pressures of 100s of GPa. The peak shock states generate sufficient entropy such that subsequent decompression to low pressures intersects the liquid-vapor phase boundary.
View Article and Find Full Text PDFEquation-of-state (pressure, density, temperature, internal energy) and reflectivity measurements on shock-compressed CO_{2} at and above the insulating-to-conducting transition reveal new insight into the chemistry of simple molecular systems in the warm-dense-matter regime. CO_{2} samples were precompressed in diamond-anvil cells to tune the initial densities from 1.35 g/cm^{3} (liquid) to 1.
View Article and Find Full Text PDFNew topochemistry in simple molecular systems can be explored at high pressure. Here we examine the binary nitrogen/hydrogen system using Raman spectroscopy, synchrotron X-ray diffraction, synchrotron infrared microspectroscopy and visual observation. We find a eutectic-type binary phase diagram with two stable high-pressure van der Waals compounds, which we identify as (N2)6(H2)7 and N2(H2)2.
View Article and Find Full Text PDFWe report the first application of a multichannel collimator (MCC) to perform quantitative structure factor measurements of dense low-Z fluids in a diamond anvil cell (DAC) using synchrotron x-ray diffraction. The MCC design, initially developed for the Paris-Edinburgh large volume press geometry, has been modified for use with diamond anvil cells. A good selectivity of the diffracted signal of the dense fluid sample is obtained due to a large rejection of the Compton diffusion from the diamond anvils.
View Article and Find Full Text PDFBackground: A hallmark of Alzheimer's disease is the presence of senile plaques in human brain primarily containing the amyloid peptides Aβ42 and Aβ40. Many drug discovery efforts have focused on decreasing the production of Aβ42 through γ-secretase inhibition. However, identification of γ-secretase inhibitors has also uncovered mechanism-based side effects.
View Article and Find Full Text PDFMagnesium oxide (MgO) is representative of the rocky materials comprising the mantles of terrestrial planets, such that its properties at high temperatures and pressures reflect the nature of planetary interiors. Shock-compression experiments on MgO to pressures of 1.4 terapascals (TPa) reveal a sequence of two phase transformations: from B1 (sodium chloride) to B2 (cesium chloride) crystal structures above 0.
View Article and Find Full Text PDFLaser-driven shock compression experiments reveal the presence of a phase transition in MgSiO(3) over the pressure-temperature range 300-400 GPa and 10 000-16 000 K, with a positive Clapeyron slope and a volume change of ∼6.3 (±2.0) percent.
View Article and Find Full Text PDFThe Escherichia coli hygromycin phosphotransferase (hph) gene, which confers hygromycin resistance, is commonly used as a dominant selectable marker in genetically modified bacteria, fungi, plants, insects, and mammalian cells. Expression of the hph gene has rarely been reported to induce effects other than those expected. Hygromycin B is the most common dominant selectable marker used in the molecular manipulation of Histoplasma capsulatum in the generation of knockout strains of H.
View Article and Find Full Text PDFThe activity of melanosome-associated tyrosinase in human melanocytes differs based on racial skin type. In melanocytes from Black skin, tyrosinase activity is high while in White melanocytes the activity of the enzyme is low. Recent studies suggest that low tyrosinase activity in White melanocytes may be due to an acidic pH environment within the melanosome.
View Article and Find Full Text PDFThe efficacies of targeted therapies for cancer treatment are dependent on the expression of the targeted molecule in the tumors of the treated patient population. Immunohistochemistry is an attractive assay format for determining protein expression in biopsies of solid tumors, and is widely used in pathology laboratories. An optimized immunohistochemistry assay for the epidermal growth factor receptor (EGFR) has been developed for the detection of EGFR in colorectal, head and neck, and other tumors that express EGFR, and the assay is being used in colorectal cancer trials of IMC-C225 to select patients for treatment.
View Article and Find Full Text PDFThe activity of tyrosinase, the rate-limiting enzyme for melanin synthesis, is higher in Black skin melanocytes than in melanocytes derived from Caucasian skin. This variation in enzyme activity is not due to differences in tyrosinase abundance or tyrosinase gene activity, but, rather, is due to differences in the catalytic activity of preexisting tyrosinase. In melanocytes, tyrosinase is localized to the membrane of melanosomes and in Caucasian melanocytes the melanosome-bound enzyme is largely inactive.
View Article and Find Full Text PDFJ Invest Dermatol
February 2000
Treatment of human melanocyte cell cultures with the alpha-2 adrenergic receptor antagonist yohimbine results in a marked down-regulation of tyrosinase activity. A 30% decrease occurs within 12 h of exposure of cells to yohimbine (100 microM), and by 48 h tyrosinase activity in treated melanocytes is less than a fifth that of control cultures. The inhibition is dose dependent and occurs in human melanocytes derived from either black or white skin types, and also in mouse melanoma cells.
View Article and Find Full Text PDFJ Agric Food Chem
January 1999
Prevention of browning of apples slices has been difficult to achieve because of the rapidity of the enzymatic oxidation of phenolic substrates even under reduced atmospheric pressure storage. Combinations of enzymatic inhibitors, reducing agents, and antimicrobial compounds containing calcium to extend storage life were tested to decrease the browning of Red Delicious apple slices stored at 5 and 10 degrees C under normal atmospheric conditions. Treatments were devised to prevent browning for up to 5 weeks at 5 degrees C with no apparent microbial growth using dipping solutions of compounds derived from natural products consisting of 4-hexylresorcinol, isoascorbic acid, a sulfur-containing amino acid (N-acetylcysteine), and calcium propionate.
View Article and Find Full Text PDFKaposi's sarcoma-associated herpes virus (KSHV)/human herpes virus 8 (HHV8) DNA sequences have been demonstrated in Kaposi's sarcoma (KS), as well as in some acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphomas (NHL) and in multicentric Castleman's disease. Although KSHV DNA generally is abundant in KSHV-associated lymphomas, few copies of the virus are present in KS, a property that confounds detection by in situ methods. Previous in situ studies, which identified KSHV in lesions of KS, relied on the use of polymerase chain reaction (PCR) to amplify target DNA sequences before in situ hybridization (ISH) for localization or used ISH with radioactively-labeled probes to obtain adequate levels of detection sensitivity.
View Article and Find Full Text PDFCancer Epidemiol Biomarkers Prev
July 1997
Proliferating cells have a restricted three-dimensional spatial distribution within the crypt, which is the proliferative unit of the colon. Accurate quantitative and spatial analyses of S phase cells in the colon have therefore been limited by histological techniques. To overcome these limitations, S phase cells in microdissected intact colonic crypts of control, modified-starved, and refed rats were labeled by histone H3 in situ hybridization and analyzed by confocal microscopy.
View Article and Find Full Text PDFHistone H3 mRNA in situ hybridization was compared to a reference method, iododeoxyuridine (IdUrd) immunohistochemistry of tissues labeled in vivo, as a means for assessing the proportion of S-phase cells (labeling index, LI) in oral tumor and normal mucosa. Paraffin sections from 16 patients with oral squamous cell carcinoma were studied. Patients received an IdUrd infusion before the biopsy was taken.
View Article and Find Full Text PDFSeveral different methods of measuring proliferation indices have been developed, including measurements of cellular DNA content (flow cytometry), S-phase incorporation of thymidine analogues into DNA (e.g., tritiated thymidine and 5'-bromodeoxyuridine), and immunostaining of cell cycle-restricted proteins (e.
View Article and Find Full Text PDFMeasurements of cell cycle phase fractions, particularly S-phase, are useful for studies of cell biology and carcinogenesis. Up-regulation of histone gene expression is tightly coupled to the G1-S-phase transition of the cell cycle, and mRNA levels rise 30-100-fold during S-phase. Labeling of histone H3 mRNA using in situ hybridization (ISH) was assessed as a measure of S-phase cells and compared with that found using in vivo 5-bromodeoxyuridine (BrdUrd) labeling in formalin-fixed rat colonic crypts under baseline, modified 72-h starvation, and 24-h refeeding conditions.
View Article and Find Full Text PDFSpecific human papillomavirus (HPV) types have been shown to be associated with proliferative epithelial lesions with variable biological consequences in infected patients. Simultaneous infection by more than one HPV type has been infrequently reported, and its clinical significance is unknown. We have examined four biopsies of cervical and vulvar tissue, each with evidence of infection by two different HPVs.
View Article and Find Full Text PDFThis study evaluates five cryptic plasmid-derived DNA probes in a 4-h slot-blot hybridization assay for the detection of Chlamydia trachomatis in cultures and clinical specimens. The probes, consisting of either the entire cloned 7.5 kbp cryptic plasmid pSE8 or one of four Hin dIII/Eco RI fragments measuring 710, 1055, 710, and 500 bp, respectively, were labelled with Photoprobe biotin.
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