Ions Traces Substitution in Stoichiometric Calcium-Hydroxyapatite: Structural Analysis by Rietveld Refinement

Impact of trace ions as Mg2+, Na+, Sr2+, SO42-, and CO32- on stoichiometric hydroxyapatite (Ca10(PO4)6(OH)2) crystal structure is investigated. The first four ions are brought by the raw material while the carbonate group is due to contamination by air. The powders were prepared, under industrial conditions, at 22°C from aqueous solutions by reaction between the calcium hydroxide and orthophosphoric acid at pH from 7 to 7.5. Two samples of hydroxyapatite powder, which differ by the content of ions trace, calcined at 1100°C have been investigated by X-ray powder patterns fitting methods. Results showed that in the absence of ion traces, the partial replacement of PO43- by CO32- groups leads to the - relaxation of the lattice by creation of vacant calcium (Ca1 and Ca2) sites, - reduction of the cell parameters, and new lattice rearrangement with lower PO4 distortion index, (Dind = 0.488) compared to the calculated theoretical value (Dind=3.079). For trace ions incorporated hydroxyapatite sample, the presence of traces cation favors the incorporation of carbonate ions. Coupled substitution on Ca2 and P position affect neither theoretical structure nor thermal stability of the hydroxyapatite but causes vacancies creation in calcium (Ca1) and oxygen (O1 and O3) sites. This structural change leads to a slight lattice distortion (Dind=3.204). Composition and microstructure of analyzed materials appear very promising for biological applications. Keywords: Biomaterials, Calcium-hydroxyapatite, Traces ions, Crystalline structure

Statefinder Parameters for Different Dark Energy Models with Variable G Correction in Kaluza-Klein Cosmology

In this work, we have calculated the deceleration parameter, statefinder parameters and EoS parameters for different dark energy models with variable $G$ correction in homogeneous, isotropic and non-flat universe for Kaluza-Klein Cosmology. The statefinder parameters have been obtained in terms of some observable parameters like dimensionless density parameter, EoS parameter and Hubble parameter for holographic dark energy, new agegraphic dark energy and generalized Chaplygin gas models.Comment: 9 pages, no figure, accepted for publication in IJTP. arXiv admin note: text overlap with arXiv:1104.2366 by other author

Fractional Action Cosmology with Power Law Weight Function

Motivated by an earlier work on fractional-action cosmology with a periodic weight function [1], we extend it by choosing a power-law weight function in the action. In this approach, we obtain a varying gravitational coupling constant. We then model dark energy in this paradigm and obtain relevant cosmological parameters.Comment: 12 pages, 9 figures, Contributed talk published in the proceedings of "3rd Italian-Pakistani Workshop on Relativistic Astrophysics

Quantum key distribution in terms of the Greenberger-Horne-Zeilinger state: multi-key generation

In this paper, we develop a quantum key distribution protocol based on the Greenberger-Horne-Zeilinger states (GHZs). The particles are exchanged among the users in blocks through two steps. In this protocol, for three-particle GHZs three keys can be simultaneously generated. The advantage of this is that the users can select the most suitable key for communication. The protocol can be generalized to $N$ users to provide $N$ keys. The protocol has two levels for checking the eavesdroppers. Moreover, we discuss the security of the protocol against different attacks.Comment: 10 Page, no figures. Comments are most welcom

Molecular identification of adenoviruses associated with respiratory infection in Egypt from 2003 to 2010.

BACKGROUND: Human adenoviruses of species B, C, and E (HAdV-B, -C, -E) are frequent causative agents of acute respiratory infections worldwide. As part of a surveillance program aimed at identifying the etiology of influenza-like illness (ILI) in Egypt, we characterized 105 adenovirus isolates from clinical samples collected between 2003 and 2010. METHODS: Identification of the isolates as HAdV was accomplished by an immunofluorescence assay (IFA) and confirmed by a set of species and type specific polymerase chain reactions (PCR). RESULTS: Of the 105 isolates, 42% were identified as belonging to HAdV-B, 60% as HAdV-C, and 1% as HAdV-E. We identified a total of six co-infections by PCR, of which five were HAdV-B/HAdV-C co-infections, and one was a co-infection of two HAdV-C types: HAdV-5/HAdV-6. Molecular typing by PCR enabled the identification of eight genotypes of human adenoviruses; HAdV-3 (n = 22), HAdV-7 (n = 14), HAdV-11 (n = 8), HAdV-1 (n = 22), HAdV-2 (20), HAdV-5 (n = 15), HAdV-6 (n = 3) and HAdV-4 (n = 1). The most abundant species in the characterized collection of isolates was HAdV-C, which is concordant with existing data for worldwide epidemiology of HAdV respiratory infections. CONCLUSIONS: We identified three species, HAdV-B, -C and -E, among patients with ILI over the course of 7 years in Egypt, with at least eight diverse types circulating

Ethnic Inequalities in Mortality: The Case of Arab-Americans

BACKGROUND: Although nearly 112 million residents of the United States belong to a non-white ethnic group, the literature about differences in health indicators across ethnic groups is limited almost exclusively to Hispanics. Features of the social experience of many ethnic groups including immigration, discrimination, and acculturation may plausibly influence mortality risk. We explored life expectancy and age-adjusted mortality risk of Arab-Americans (AAs), relative to non-Arab and non-Hispanic Whites in Michigan, the state with the largest per capita population of AAs in the US. METHODOLOGY/PRINCIPAL FINDINGS: Data were collected about all deaths to AAs and non-Arab and non-Hispanic Whites in Michigan between 1990 and 2007, and year 2000 census data were collected for population denominators. We calculated life expectancy, age-adjusted all-cause, cause-specific, and age-specific mortality rates stratified by ethnicity and gender among AAs and non-Arab and non-Hispanic Whites. Among AAs, life expectancies among men and women were 2.0 and 1.4 years lower than among non-Arab and non-Hispanic White men and women, respectively. AA men had higher mortality than non-Arab and non-Hispanic White men due to infectious diseases, chronic diseases, and homicide. AA women had higher mortality than non-Arab and non-Hispanic White women due to chronic diseases. CONCLUSIONS/SIGNIFICANCE: Despite better education and higher income, AAs have higher age-adjusted mortality risk than non-Arab and non-Hispanic Whites, particularly due to chronic diseases. Features specific to AA culture may explain some of these findings

Haemorrhage-related maternal mortality in Bangladesh: levels, trends, time of death, and care-seeking practices based on nationally representative population-based surveys

Background Haemorrhage is a major cause of maternal deaths globally, most of which are preventable and predominantly happen in low and middle-income countries, including Bangladesh. We examine the current levels, trends, time of death, and care-seeking practices for haemorrhage-related maternal deaths in Bangladesh. Methods We conducted a secondary analysis with data from the nationally representative 2001, 2010, and 2016 Bangladesh Maternal Mortality Surveys (BMMS). The cause of death information was collected through verbal autopsy (VA) interviews using a country-adapted version of the standard World Health Organization VA questionnaire. Trained physicians reviewed the VA questionnaire and assigned the cause of death using the International Classification of Diseases (ICD) codes. Results Haemorrhage accounted for 31% (95% confidence interval (CI) = 24-38) of all maternal deaths in 2016 BMMS, which was 31% (95% CI = 25-41) in 2010 BMMS and 29% (95% CI = 23-36) in 2001 BMMS. The haemorrhage-specific mortality rate remained unchanged between 2010 BMMS (60 per 100 000 live births, uncertainty range (UR) = 37-82) and 2016 BMMS (53 per 100 000 live births, UR = 36-71). Around 70% of haemorrhage-related maternal deaths took place within 24 hours of delivery. Of those who died, 24% did not seek health care outside the home and 15% sought care from more than three places. Approximately two-thirds of the mothers who died due to haemorrhage gave birth at home. Conclusions Postpartum haemorrhage remains the primary cause of maternal mortality in Bangladesh. To reduce these preventable deaths, the Government of Bangladesh and stakeholders should take steps to ensure community awareness about care-seeking during delivery

Oestrogen blocks the nuclear entry of SOX9 in the developing gonad of a marsupial mammal

<p>Abstract</p> <p>Background</p> <p>Hormones are critical for early gonadal development in nonmammalian vertebrates, and oestrogen is required for normal ovarian development. In contrast, mammals determine sex by the presence or absence of the <it>SRY </it>gene, and hormones are not thought to play a role in early gonadal development. Despite an XY sex-determining system in marsupial mammals, exposure to oestrogen can override <it>SRY </it>and induce ovarian development of XY gonads if administered early enough. Here we assess the effect of exogenous oestrogen on the molecular pathways of mammalian gonadal development.</p> <p>Results</p> <p>We examined the expression of key testicular (<it>SRY</it>, <it>SOX9</it>, <it>AMH </it>and <it>FGF9</it>) and ovarian (<it>WNT4</it>, <it>RSPO1</it>, <it>FOXL2 </it>and <it>FST</it>) markers during gonadal development in the marsupial tammar wallaby (<it>Macropus eugenii</it>) and used these data to determine the effect of oestrogen exposure on gonadal fate. During normal development, we observed male specific upregulation of <it>AMH </it>and <it>SOX9 </it>as in the mouse and human testis, but this upregulation was initiated before the peak in <it>SRY </it>expression and 4 days before testicular cord formation. Similarly, key genes for ovarian development in mouse and human were also upregulated during ovarian differentiation in the tammar. In particular, there was early sexually dimorphic expression of <it>FOXL2 </it>and <it>WNT4</it>, suggesting that these genes are key regulators of ovarian development in all therian mammals. We next examined the effect of exogenous oestrogen on the development of the mammalian XY gonad. Despite the presence of <it>SRY</it>, exogenous oestrogen blocked the key male transcription factor SOX9 from entering the nuclei of male somatic cells, preventing activation of the testicular pathway and permitting upregulation of key female genes, resulting in ovarian development of the XY gonad.</p> <p>Conclusions</p> <p>We have uncovered a mechanism by which oestrogen can regulate gonadal development through the nucleocytoplasmic shuttling of SOX9. This may represent an underlying ancestral mechanism by which oestrogen promotes ovarian development in the gonads of nonmammalian vertebrates. Furthermore, oestrogen may retain this function in adult female mammals to maintain granulosa cell fate in the differentiated ovary by suppressing nuclear translocation of the SOX9 protein.</p> <p>See commentary: http://www.biomedcentral.com/1741-7007/8/110</p