Drained residual shear strength of fine-grained soils and soil-solid interfaces at low to medium effective normal stresses: Analyses and Applications

A laboratory research program was undertaken to study the large-strain shear strength characteristics of fine-grained soils under low effective normal stresses (~3 to 6 kPa). Soils that cover a wide range of plasticity and composition were utilized in the program. The interface shear strength of these soils against a number of solid surfaces having different roughness was also investigated at similar low effective normal stress levels. The findings contribute to advancing the knowledge on the parameters needed for the design of pipelines placed on sea beds and the stability analysis of shallow soil slopes. A Bromhead-type torsional ring shear apparatus was modified to suit measuring soil-soil and soil-solid interface drained residual shear strengths at the low effective normal stresses. In consideration of increasing the accuracy of assessment and depicting the full-scale field behavior, the interface residual shear strengths measured using the modified ring shear apparatus were compared with those measured by research collaborators for similar interfaces using a macro-scale interface direct shear device with a plan interface shear area of approximately 3.0 m2. Correlations are developed to estimate the soil-soil and soil-solid interface residual shear strengths at low effective normal stresses. The correlations are compared with soil-soil and soil-solid interface drained residual shear strengths and correlations presented in the literature. Data of torsional ring shear tests at a wide range of effective normal stress (10 to 700 kPa) for soils, mudstones and shales of different plasticity and gradation were analyzed. The data were made available for this research to study the effects of the change in non linearity of shear strength envelope over the normal stress ranges relevant to soil slope stability analyses. Using this data set, new empirical residual shear strength correlations were developed as a function of soil index parameters and wide range of effective normal stresses. In essence, the correlations are presented as revised versions of those previously developed for a limited number of normal stresses utilizing the same soil index parameters. Comparisons were made with a considerable amount of back-calculated shear strength data reported in the literature for reactivated landslides as well as results predicted from existing shear strength correlations to verify the increased suitability of the new correlations for use in slope stability analyses. A numerical expression was also introduced to express the residual shear strength correlations for direct incorporation in slope stability software.Qatar National Research Fund (QNRF), Qatar, under Projects No: NPRP 08–203–2–064, and NPRP 5-488-2-19

Composite autogenous bone and demineralized bone matrix: an effective graft material

Abstract no. 3131published_or_final_versio

Bone remodeling in adult rats' condyles under mechanical strain

published_or_final_versio

Virological response without CD4 recovery

The objective of antiretroviral therapy (ART) is to suppress viral replication so that immune restoration can occur. Failure of immune restoration is usually associated with poor virological suppression. In children a good immunological and clinical response to ART is often achieved despite incomplete viral suppression. However, we have recently managed a number of children in whom immune restoration did not occur despite excellent virological suppression. We present a case, discuss possible causes and speculate on the appropriate course of action. Southern African Journal of HIV Medicine Vol. 7 (3) 2006: pp. 45-4

Immune reconstitution inflammatory syndrome in children

Paradoxical deterioration due to immune reconstitution inflammatory syndrome (IRIS) occurs in up to 21% of children initiating antiretroviral therapy. Mycobacterial diseases are the most common, with BCG-vaccine adenitis predominating in infants and Mycobacterium tuberculosis (TB) in older children. The difficulty of diagnosing TB in HIV-infected children and the increasing risk of drug-resistant TB complicate the diagnosis and  management of both paradoxical IRIS and post-antiretroviral therapy TB. History and clinical assessment remain key strategies in the management of these infants and children. There are no prospective studies investigating diagnostic criteria and therapeutic strategies in children

Importance of tetrahedral coordination for high-valent transition metal oxides: YCrO4_4 as a model system

We have investigated the electronic structure of the high oxidation state material YCrO$_4$ within the framework of the Zaanen-Sawatzky-Allen phase diagram. While Cr$^{4+}$-based compounds like SrCrO$_3$/CaCrO$_3$ and CrO$_2$ can be classified as small-gap or metallic negative-charge-transfer systems, we find using photoelectron spectroscopy that YCrO$_4$ is a robust insulator despite the fact that its Cr ions have an even higher formal valence state of 5+. We reveal using band structure calculations that the tetrahedral coordination of the Cr$^{5+}$ ions in YCrO$_4$ plays a decisive role, namely to diminish the bonding of the Cr $3d$ states with the top of the O $2p$ valence band. This finding not only explains why the charge-transfer energy remains effectively positive and the material stable, but also opens up a new route to create doped carriers with symmetries different from those of other transition-metal ions.Comment: 6 pages, 6 figure

PTHrP regulates chondrocyte maturation in condylar cartilage

PTHrP is a key factor regulating the pace of endochondral ossification during skeletal development. Mandibular advancement solicits a cascade of molecular responses in condylar cartilage. However, the pace of cellular maturation and its effects on condylar growth are still unknown. The purpose of this study was to evaluate the pattern of expression of PTHrP and correlate it to cellular dynamics of chondrocytes in condylar cartilage during natural growth and mandibular advancement. We fitted 35-day-old Sprague-Dawley rats with functional appliances. Experimental animals with matched controls were labeled with bromodeoxyuridine 3 days before their death, so that mesenchymal cell differentiation could be traced. Mandibular advancement increased the number of differentiated chondroblasts and subsequently increased the cartilage volume. Higher levels of PTHrP expression in experimental animals coincided with the slowing of chondrocyte hypertrophy. Thus, mandibular advancement promoted mesenchymal cell differentiation and triggered PTHrP expression, which retarded their further maturation to allow for more growth.published_or_final_versio

Accounting for variation in designing greenhouse experiments with special reference to greenhouses containing plants on conveyor systems

Extent: 21p.Background: There are a number of unresolved issues in the design of experiments in greenhouses. They include whether statistical designs should be used and, if so, which designs should be used. Also, are there thigmomorphogenic or other effects arising from the movement of plants on conveyor belts within a greenhouse? A two-phase, single-line wheat experiment involving four tactics was conducted in a conventional greenhouse and a fully-automated phenotyping greenhouse (Smarthouse) to investigate these issues. Results and discussion: Analyses of our experiment show that there was a small east–west trend in total area of the plants in the Smarthouse. Analyses of the data from three multiline experiments reveal a large north–south trend. In the single-line experiment, there was no evidence of differences between trios of lanes, nor of movement effects. Swapping plant positions during the trial was found to decrease the east–west trend, but at the cost of increased error variance. The movement of plants in a north–south direction, through a shaded area for an equal amount of time, nullified the north–south trend. An investigation of alternative experimental designs for equally-replicated experiments revealed that generally designs with smaller blocks performed best, but that (nearly) trend-free designs can be effective when blocks are larger. Conclusions: To account for variation in microclimate in a greenhouse, using statistical design and analysis is better than rearranging the position of plants during the experiment. For the relocation of plants to be successful requires that plants spend an equal amount of time in each microclimate, preferably during comparable growth stages. Even then, there is no evidence that this will be any more precise than statistical design and analysis of the experiment, and the risk is that it will not be successful at all. As for statistical design and analysis, it is best to use either (i) smaller blocks, (ii) (nearly) trend-free arrangement of treatments with a linear trend term included in the analysis, or, as a last resort, (iii) blocks of several complete rows with trend terms in the analysis. Also, we recommend that the greenhouse arrangement parallel that in the Smarthouse, but with randomization where appropriate.Chris J Brien, Bettina Berger, Huwaida Rabie and Mark Teste

Prevalence, Types and Determinants of Complementary and Alternative Medications among Health Clinic Clients

Complementary and Alternative Medicine (CAM) covers a wide range of over 100 healing approaches, philosophies and therapeutic modalities that are not provided by conventional medicine. Complementary and Alternative Medicine (CAM) covers a wide range of healing approaches not provided by conventional medicine. Objectives: The study was aimed at identifying the prevalence , types and determinants of CAM use,  sources of information about CAM that patients usually depend upon and  reasons of using CAM, Methods: : A cross-sectional survey was used to collect data from random consecutive patients attending  two PHC centres out of ten which was selected randomly in Abha city. All the patients more than 18 years attended to the clinic during two months (March & April) /2014 was included in the study. Results: The present study included 504 patients attending the PHC centres. The mean age of the participants was  47.6 ± 10.2 years. 232(46.0%)  were Males and 272(54.0%) were females. The majority of participants were Saudi ((88.7%)) and Muslims (96.4%). Most of the participants were Illiterate or school level (82.1%) and less than half of them (42.9%) had  enough family income > 10,000 SR. About three fourths of the participants were born in city, most of them were non smokers (81.9%) and about one third of them had self-perceived stress level more than 5. About one third  (36.9%) of participants reported using CAM during the 12 months preceded the study. About half of the participants used CAM due to the personal and family beliefs and because of friends advice ( 63.4% & 46.8% ) respectively. More than half of CAM users used it regularly. 58.6% of CAM users Feeling physically & psychologically better after using it and most of them did not reported any side effects after using CAM.  Conclusions: Use of CAM is prevalent among patients attending  health clinics in Abha City. CAM is commonly used by all age groups. The significant factors found to increase the likelihood of CAM use were Saudi nationality, Illiterate and the place of birth, there were a statistical significant increase  of using CAM among participants born in village. However, factors like age, gender, income, religion, smoking and perceived stress level did not prove to be statistically significant and thus did not affect CAM prevalence significantly. Most families has strong personal belief on CAM Because of the Belief that CAM builds up the body’s own defenses and promotes self-healing and has less side effects. Key words: Prevalence, Determinants, Complementary,  Alternative Medications, Client

Paediatric ART outcomes in a decentralised model of care in Cape Town, South Africa

Background. Although subSaharan Africa faces the world’s largest paediatric HIV epidemic, only 1 in 4 children has access to combination antiretroviral therapy (ART). A decentralised approach to HIV care is  advocated, but programmes in resourcelimited settings encounter many challenges to community-initiated paediatric ART implementation.Methods. A retrospective cohort analysis of 613 children receiving ART between 2004 and 2009 was performed in seven physician-run primary healthcare (PHC) clinics in Cape Town. Baseline characteristics, serial CD4+, viral load (VL) levels and status at study closure were collected.Results. Two subgroups were identified: children who were initiated on ART in a PHC clinic (n=343) and children who were down-referred from tertiary hospitals (n=270). The numbers of children initiated on ART in PHC increased sevenfold over the study period. Down-referred children were severely ill at ART initiation, with higher VLs, lower CD4+ counts and higher rates of tuberculosis co-infection (25.3% v. 16.9%; p=0.01). Median time to virological suppression was 29 weeks in PHC-ART initiates and 44 weeks in children down-referred (p<0.0001). Children down-referred to PHC either maintained or gained virological suppression. Longitudinal cohort analysis demonstrated sustained VL suppression >80%, high rates of immune reconstitution and low mortality.Conclusions. Increasing numbers of children are initiated on ART in PHC settings and achieve comparable immunological, virological and survival outcomes, suggesting successful decentralisation of paediatric HIV care. Down-referral of children with adherence-related virological failure may  assist with attainment of virological suppression and sparing use of  second-line medications