Processing–structure–property relations of chemically bonded phosphate ceramic composites

ABSTRACT: Mechanical properties and microstructures of a chemically bonded phosphate ceramic (CBPC) and its composite with 1⋅0 wt% graphite nanoplatelets (GNPs) reinforcement have been investigated. Microstructure was identified by using optical and scanning electron microscopes, X-ray tomography, and X-ray diffraction. In addition, weight loss of the resin at room temperature was studied. The microstructure characterization shows that CBPC is itself a composite with several crystalline (wollastonite and brushite) and amorphous phases. SEM and micro tomography show a homogeneous distribution of crystalline phases. Bending and compression strength of the CBPC was improved by reducing bubbles via preparation in vacuum

HCV Infection among Saudi Population: High Prevalence of Genotype 4 and Increased Viral Clearance Rate

HCV is a major etiological agent of liver disease with a high rate of chronic evolution. The virus possesses 6 genotypes with many subtypes. The rate of spontaneous clearance among HCV infected individuals denotes a genetic determinant factor. The current study was designed in order to estimate the rate of HCV infection and ratio of virus clearance among a group of infected patients in Saudi Arabia from 2008 to 2011. It was additionally designed to determine the genotypes of the HCV in persistently infected patients. HCV seroprevalence was conducted on a total of 15,323 individuals. Seropositive individuals were tested by Cobas AmpliPrep/Cobas TaqMan HCV assay to determine the ratio of persistently infected patients to those who showed spontaneous viral clearance. HCV genotyping on random samples from persistently infected patients were conducted based on the differences in the 5′untranslated region (5′UTR). Anti-HCV antibodies were detected in 7.3% of the totally examined sera. A high percentage of the HCV infected individuals experienced virus clearance (48.4%). HCV genotyping revealed the presence of genotypes 1 and 4, the latter represented 97.6% of the tested strains. Evidences of the widespread of the HCV genotype 4 and a high rate of HCV virus clearance were found in Saudi Arabia

Histological observation related to the use of laser and ultrasound on bone fracture healing

Objective: To study the effect of both laser and ultrasound radiation on bone fracture healing process. Materials and Methods: Nd:YAG laser (1064 nm wavelength, 135 mW power, 16 joules energy) and ultrasound (1 MHz frequency, 50 mW/cm2 power intensity) were used in this work. Fifteen mature, male, albino rats, were divided into three groups and subjected to a partial fracture on the lateral aspect of femur by a sharp blade. The fi rst group of these animals served as control group. The second group was illuminated by the Nd:YAG laser for two minutes; the fi rst dose was given immediately after surgical fracture induction; the other doses were given on days two, three, six and then one dose weekly for the next three weeks while the third group were treated by the addition of the CW ultrasound perpendicular to the laser treatment in the second group. Results: The present study showed that ultrasound increases the penetration of laser power through the tissue. The histological assessments at day 28 after the fracture of fi rst group showed incomplete healing of the bone with disfi guration and disarrangement of Haversian system and the periosteum was not yet well developed. Treatment with laser showed irregularity and lack of Haversian system formation in bone healing of the second group. The laser and ultrasound treated group (third group) expressed a complete healing at the site of fracture with a complete layer of periosteum and a well arranged Haversian system. Conclusion: Combination of laser and ultrasound in therapy can enhance healing process of a fractured bone more than laser therapy alone, as ultrasound increases the depth of laser penetration in tissue

Physiological and biochemical parameters: new tools to screen barley root exudates allelopathic potential (*Hordeum vulgare* L. subsp. *vulgare*

peer reviewedMorphological markers/traits are often used in the detection of allelopathic stress, but optical signals including chlorophyll a fluorescence emission could be useful in developing new screening techniques. In this context, the allelopathic effect of barley (Hordeum vulgare subsp. vulgare) root exudates (three modern varieties and three landraces) were assessed on the morphological (root and shoot length, biomass accumulation), physiological (Fv/Fm and F0), and biochemical (chlorophyll and protein contents) variables of great brome (Bromus diandrus Roth., syn. Bromus rigidus Roth. subsp. gussonii Parl.). All the measured traits were affected when great brome was grown in a soil substrate in which barley plants had previously developed for 30 days before being removed. The response of receiver plants was affected by treatment with activated charcoal, dependent on barley genotype and on the nature of the growing substrate. The inhibitory effect was lower with the addition of the activated charcoal suggesting the release of putative allelochemicals from barley roots into the soil. The barley landraces were more toxic than modern varieties and their effect was more pronounced in sandy substrate than in silty clay sand substrate. In our investigation, the chlorophyll content and Fv/Fm were the most correlated variables with barley allelopathic potential. These two parameters might be considered as effective tools to quantify susceptibility to allelochemical inhibitors in higher plants