Evaluation of a spacecraft nitrogen generator

An experiment was completed to demonstrate that low ammonia concentrations in the product nitrogen stream are possible using the staging concept. Mixtures of nitrogen, hydrogen and ammonia were fed into a temperature controlled packed bed ammonia dissociator. An ammonia concentration of 1.03% in the feed stream was reduced to less than 50 ppm at temperatures greater than or equal to 777K. The actual inlet ammonia concentration to the final nitrogen generation module ammonia dissociation stage was only 0.09%

Switching of the magnetic order in CeRhIn5−x_{5-x}Snx_{x} in the vicinity of its quantum critical point

We report neutron diffraction experiments performed in the tetragonal antiferromagnetic heavy fermion system CeRhIn$_{5-x}$Sn$_{x}$ in its ($x$, $T$) phase diagram up to the vicinity of the critical concentration $x_c$ $\approx$ 0.40, where long range magnetic order is suppressed. The propagation vector of the magnetic structure is found to be $\bf{k_{IC}}$=(1/2, 1/2, $k_l$) with $k_l$ increasing from $k_l$=0.298 to $k_l$=0.410 when $x$ increases from $x$=0 to $x$=0.26. Surprisingly, for $x$=0.30, the order has changed drastically and a commensurate antiferromagnetism with $\bf{k_{C}}$=(1/2, 1/2, 0) is found. This concentration is located in the proximity of the quantum critical point where superconductivity is expected.Comment: 5 pages, 5 figures, submitted to Phys. Rev.

Middle Atlantic Outer Continental Shelf Environmental Studies Volume III: Geologic Studies

The Middle Atlantic Outer Continental Shelf Environmental Studies is comprised of three volumes. Volume I. Executive Summary. Volume IIA, IIB, IIC and IID. Chemical and Biological Benchmark Studies. Volume III. Geologic Studies. This third volume in the study contains the following: CHAPTER 1. INTRODUCTION by Harley J. Knebel CHAPTER 2. BOTTOM CURRENTS AND BOTTOM SEDIMENT MOBILITY IN THE OFFSHORE MIDDLE ATLANTIC BIGHT, 1976-1977 by Bradford Butman and Marlene Noble CHAPTER 3. SESTON IN MIDDLE ATLANTIC SHELF AND SLOPE WATERS 1976-1977 by John D. Milliman, Michael H. Bothner, and Carol M. Parmenter CHAPTER 4. SUBMERSIBLE OBSERVATIONS OF THE BOTTOM IN LEASE AREAS IN THE BALTIMORE CANYON TROUGH by Sally A. Wood and David W. Folger CHAPTER 5. MEDIUM-SCALE POTENTIALLY MOBILE BED FORMS ON THE MID-ATLANTIC CONTINENTAL SHELF by David C. Twichell CHAPTER 6. C15+ HYDROCARBON GEOCHEMISTRY OF MID-ATLANTIC OUTER CONTINENTAL SHELF SEDIMENTS by R. E. Miller, D. M. Schultz, H. Lerch, D. Ligon, D. Doyle, and C. Gary CHAPTER 7. GEOTECHNICAL ENGINEERING STUDIES IN THE BALTIMORE CANYON TROUGH AREA by Dwight A. Sangrey and Harley J. Knebel CHAPTER 8. AN INSTRUMENT SYSTEM FOR LONG-TERM SEDIMENT TRANSPORT STUDIES ON THE CONTINENTAL SHELF by Bradford Butman and David w. Folge

Similarity of Fermi Surface in the Hidden Order State and in the Antiferromagnetic State of URu2Si2

Shubnikov-de Haas measurements of high quality URu2Si2 single crystals reveal two previously unobserved Fermi surface branches in the so-called hidden order phase. Therefore about 55% of the enhanced mass is now detected. Under pressure in the antiferromagnetic state, the Shubnikov-de Haas frequencies for magnetic fields applied along the crystalline c axis show little change compared with the zero pressure data. This implies a similar Fermi surface in both the hidden order and antiferromagnetic states, which strongly suggests that the lattice doubling in the antiferromagnetic phase due to the ordering vector QAF = (0 0 1) already occurs in the hidden order. These measurements provide a good test for existing or future theories of the hidden order parameter.Comment: 4 pages, 4 figure

Entry pathways of herpes simplex virus type 1 into human keratinocytes are dynamin- and cholesterol-dependent

Herpes simplex virus type 1 (HSV-1) can enter cells via endocytic pathways or direct fusion at the plasma membrane depending on the cell line and receptor(s). Most studies into virus entry have used cultured fibroblasts but since keratinocytes represent the primary entry site for HSV-1 infection in its human host, we initiated studies to characterize the entry pathway of HSV-1 into human keratinocytes. Electron microscopy studies visualized free capsids in the cytoplasm and enveloped virus particles in vesicles suggesting viral uptake both by direct fusion at the plasma membrane and by endocytic vesicles. The ratio of the two entry modes differed in primary human keratinocytes and in the keratinocyte cell line HaCaT. Inhibitor studies further support a role for endocytosis during HSV-1 entry. Infection was inhibited by the cholesterol-sequestering drug methyl-beta-cyclodextrin, which demonstrates the requirement for host cholesterol during virus entry. Since the dynamin-specific inhibitor dynasore and overexpression of a dominant-negative dynamin mutant blocked infection, we conclude that the entry pathways into keratinocytes are dynamin-mediated. Electron microscopy studies confirmed that virus uptake is completely blocked when the GTPase activity of dynamin is inhibited. Ex vivo infection of murine epidermis that was treated with dynasore further supports the essential role of dynamin during entry into the epithelium. Thus, we conclude that HSV-1 can enter human keratinocytes by alternative entry pathways that require dynamin and host cholesterol

Performance of p16INK4a ELISA as a primary cervical cancer screening test among a large cohort of HIV-infected women in western Kenya: a 2-year cross-sectional study.

ObjectiveA biomarker with increased specificity for cervical dysplasia compared with human papillomavirus (HPV) testing would be an attractive option for cervical cancer screening among HIV-infected women in resource-limited settings. p16(INK4a) has been explored as a biomarker for screening in general populations.DesignA 2-year cross-sectional study.Setting2 large HIV primary care clinics in western Kenya.Participants1054 HIV-infected women in western Kenya undergoing cervical cancer screening as part of routine HIV care from October 2010 to November 2012.InterventionsParticipants underwent p16(INK4a) specimen collection and colposcopy. Lesions with unsatisfactory colposcopy or suspicious for cervical intraepithelial neoplasia 2+ (CIN2+; including CIN2/3 or invasive cervical cancer) were biopsied. Following biopsy, disease status was determined by histopathological diagnosis.Primary and secondary outcome measuresWe measured the sensitivity, specificity and predictive values of p16(INK4a) ELISA for CIN2+ detection among HIV-infected women and compared them to the test characteristics of current screening methods used in general as well as HIV-infected populations.ResultsAverage p16(INK4a) concentration in cervical samples was 37.4 U/mL. After colposcopically directed biopsy, 127 (12%) women were determined to have CIN2+. Receiver operating characteristic analysis showed an area under the curve of 0.664 for p16(INK4a) to detect biopsy-proven CIN2+. At a p16(INK4a) cut-off level of 9 U/mL, sensitivity, specificity, positive and negative predictive values were 89.0%, 22.9%, 13.6% and 93.8%, respectively. The overall p16(INK4a) positivity at a cut-off level of 9 U/mL was 828 (78.6%) women. There were 325 (30.8%) cases of correct p16(INK4a) prediction to detect or rule out CIN2+, and 729 (69.2%) cases of incorrect p16(INK4a) prediction.Conclusionsp16(INK4a) ELISA did not perform well as a screening test for CIN2+ detection among HIV-infected women due to low specificity. Our study contributes to the ongoing search for a more specific alternative to HPV testing for CIN2+ detection