Influence of capillary water on compressive strength of marls

Tests of compressive strength carried out on calcareous marl samples showed very different results in the four following cases:

1. the test was made in air on a dry sample,
2. in air on a sample saturated with water by capillary rise,
3. in air on a fully water-saturated sample,
4. in water on a fully water-saturated sample.

These results are interesting on a theretical point of view, and also on a practical point of view for works to be carried out under the ground-water table.     

Single disperser design for coded aperture snapshot spectral imaging

We present a single disperser spectral imager that exploits recent theoretical work in the area of compressed sensing to achieve snapshot spectral imaging. An experimental prototype is used to capture the spatiospectral information of a scene that consists of two balls illuminated by different light sources. An iterative algorithm is used to reconstruct the data cube. The average spectral resolution is 3.6 nm per spectral channel. The accuracy of the instrument is demonstrated by comparison of the spectra acquired with the proposed system with the spectra acquired by a nonimaging reference spectrometer.     

Theoretical analyses and numerical simulations of the torsional mode for two acoustic viscometers with preliminary experimental tests

A rigorous analysis of the torsional modes in both a cylindrical wave guide and the associated static viscous fluid field has been conducted from the solid and the fluid wave equations and the coupled boundary conditions. As a result, two acoustic viscometer models, along with four independent equations connecting the density and the viscosity of the fluid with the attenuation and the phase velocity of the torsional wave in the wave guide, have been developed. The analysis shows that the product of the viscosity and the density of the fluid can be measured from the end reflection coefficient of the torsional wave in the wave guide and that both the viscosity and the density can be determined simultaneously from either the phase velocity or the attenuation of the torsional wave in a single cylindrical wave guide. For the simultaneous measurements of the viscosity and the density, the independent equations have to be solved numerically, for example, using Matlab (The MathWorks, Natick, MA), given either the attenuation or the phase velocity in the wave guide that is surrounded by the fluid. To demonstrate the technical feasibility, numerical simulations have been conducted to discern viscosity, phase velocity, and density, all versus attenuation, at different frequencies, and with variable dimension of a molybdenum rod, so that both the advantages and the disadvantages of the simultaneous measurements can be explored. In the end, to test the two models, preliminary experiments on two viscous standards were conducted at 23 degrees C, and good agreements have been achieved between the viscosities measured from both models and for both standards.     

Effect of pathogen concentrations on removal of Cryptosporidium and Giardia by conventional drinking water treatment

The presence of waterborne enteric pathogens in municipal water supplies contributes risk to public health. To evaluate the removal of these pathogens in drinking water treatment processes, previous researchers have spiked raw waters with up to 10(6) pathogens/L in order to reliably detect the pathogens in treated water. These spike doses are 6-8 orders of magnitude higher than pathogen concentrations routinely observed in practice. In the present study, experiments were conducted with different sampling methods (i.e., grab versus continuous sampling) and initial pathogen concentrations ranging from 10(1) to 10(6) pathogens/L. Results showed that Cryptosporidium oocyst and Giardia cyst removal across conventional treatment were dependent on initial pathogen concentrations, with lower pathogen removals observed when lower initial pathogen spike doses were used. In addition, higher raw water turbidity appeared to result in higher log removal for both Cryptosporidium oocysts and Giardia cysts.     

The co-occurrence of childhood sexual abuse, adult sexual assault, intimate partner violence, and sexual harassment: A mediational model of posttraumatic stress disorder and physical health outcomes.

This study examined the co-occurrence of childhood sexual abuse, adult sexual assault, intimate partner violence, and sexual harassment in a predominantly African American sample of 268 female veterans, randomly sampled from an urban Veterans Affairs hospital women's clinic. A combination of hierarchical and iterative cluster analysis was used to identify 4 patterns of women's lifetime experiences of violence co-occurrence. The 1st cluster experienced relatively low levels of all 4 forms of violence; the 2nd group, high levels of all 4 forms; the 3rd, sexual revictimization across the lifespan with adult sexual harassment; and the 4th, high intimate partner violence with sexual harassment. This cluster solution was validated in a theoretically driven model that examined the role of posttraumatic stress disorder (PTSD) as a mediator of physical health symptomatology. Structural equation modeling analyses revealed that PTSD fully mediated the relationship between violence and physical health symptomatology. Consistent with a bio-psycho-immunologic theoretical model, PTSD levels more strongly predicted pain-related physical health symptoms compared to nonpain health problems. Implications for clinical interventions to prevent PTSD and to screen women for histories of violence in health care settings are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

All in the mind's eye? Anger rumination and reappraisal.

Research on rumination has demonstrated that compared with distraction, rumination intensifies and prolongs negative emotion. However, rumination and distraction differ both in what one thinks about and how one thinks about it. Do the negative outcomes of rumination result from how people think about negative events or simply that they think about them at all? To address this question, participants in 2 studies recalled a recent anger-provoking event and then thought about it in 1 of 2 ways: by ruminating or by reappraising. The authors examined the impact of these strategies on subsequent ratings of anger experience (Study 1) as well as on perseverative thinking and physiological responding over time (Study 2). Relative to reappraisal, rumination led to greater anger experience, more cognitive perseveration, and greater sympathetic nervous system activation. These findings provide compelling new evidence that how one thinks about an emotional event can shape the emotional response one has. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gelatin sponges (Gelfoam ® ) as a scaffold for osteoblasts

Gelatine sponge because of its flexibility, biocompatibility, and biodegradability, has the potential to be used as a scaffold to support osteoblasts and to promote bone regeneration in defective areas. This study aimed to determine osteoblast proliferation, differentiation, and integration in modified and un-modified gelatine sponges. Three scaffolds were studied: gelatine sponge (Gelfoam), gelatin sponge/mineral (hydroxyapatite) composite, and gelatin sponge/polymer (poly-lactide-co-glycolide) composite. 2-D plastic coverslip was used as control. The gelatin sponges were modified using PLGA coating and mineral deposition to increase biodegradation resistance and osteoblast proliferation respectively. The scaffolds were characterized using Scanning Electron Microscopy (SEM) and X-ray diffraction. Cell number (DNA content), cell-replication rate (thymidine assay), and cell differentiation (alkaline phosphatase activity) were measured 24 h, 3 days, and 1, 2, 3 weeks after the osteoblast-like cells were cultured onto the scaffolds. Cell penetration into the sponges was determined using haematoxylin-eosin staining. Both modified and unmodified gelatine sponges demonstrated ability to support cell growth and cells were able to penetrate into the sponge pores. In a comparison of different scaffolds, cell number and cell replication were highest in sponge/hydroxyapatite composite and lowest in sponge/PLGA composite.     

Maintenance of meiotic arrest in bovine oocytes using the S-enantiomer of roscovitine: effects on maturation, fertilization and subsequent embryo development in vitro

The overall objective was to evaluate the effectiveness of the S-enantiomer of roscovitine (inhibitor of p34cdc2/cyclin B kinase) to maintain bovine cumulus-oocyte complexes at the germinal vesicle (GV) stage for extended times after removal from antral follicles without compromising subsequent maturation, fertilization and embryo development. Oocytes were cultured in 0, 12.5, 25 or 50 micromol/l S-roscovitine for 24 h. Hoechst staining showed that 50 micromol/l S-roscovitine maintained >90% of oocytes at the GV stage and inhibited gonadotropin-induced cumulus expansion. Fewer oocytes underwent nuclear maturation after in vitro maturation (Hoechst staining) when cultured in 50 micromol/l S-roscovitine for 66 versus 21 or 42 h. Zona pellucida (ZP) hardening (pronase resistance), cortical granule types (lens culinaris agglutinin-fluorescein isothiocyanate), nuclear maturation and fertilization with frozen-thawed spermatozoa (Hoechst staining) were assessed after culture of oocytes in 50 micromol/l S-roscovitine for 0, 24 or 48 h. Neither ZP hardening, nor nuclear maturation nor fertilization were altered by roscovitine culture for 48 h. A higher proportion of oocytes had a type III cortical granule pattern (premature translocation to the oolemma) after roscovitine culture for 48 h. However, embryo development was not compromised as cleavage, development to 8-16 cell and blastocyst stages were at least comparable in control and roscovitine-treated oocytes. In conclusion, the studies have shown that S-roscovitine reversibly maintained bovine oocytes at the GV stage for 48 h. However, maintenance of oocytes in static culture for 48 h was not sufficient to improve development above non-treated controls.