Molecular Mechanics Study of the Cyclic and Unsymmetric Diborane(4) Compounds

The results of a theoretical study on the structure of some diborane(4) compounds are presented in order to analyze the issue related to the relative stabilities of the 1,1- vs. 1,2-isomers. Through the employment of the molecular mechanics method, characteristic distances and angles are given and they are compared with available experimental data. In order to rationalize the results, the different energy components are discussed in a comparative fashion. We find a rather satisfactory agreement between theoretical and experimental data. Some possible future extensions are pointed out to complement this sort of analysis

Mimicry and well known genetic friends: molecular diagnosis in an Iranian cohort of suspected Bartter syndrome and proposition of an algorithm for clinical differential diagnosis.

BACKGROUND: Bartter Syndrome is a rare, genetically heterogeneous, mainly autosomal recessively inherited condition characterized by hypochloremic hypokalemic metabolic alkalosis. Mutations in several genes encoding for ion channels localizing to the renal tubules including SLC12A1, KCNJ1, BSND, CLCNKA, CLCNKB, MAGED2 and CASR have been identified as underlying molecular cause. No genetically defined cases have been described in the Iranian population to date. Like for other rare genetic disorders, implementation of Next Generation Sequencing (NGS) technologies has greatly facilitated genetic diagnostics and counseling over the last years. In this study, we describe the clinical, biochemical and genetic characteristics of patients from 15 Iranian families with a clinical diagnosis of Bartter Syndrome. RESULTS: Age range of patients included in this study was 3 months to 6 years and all patients showed hypokalemic metabolic alkalosis. 3 patients additionally displayed hypercalciuria, with evidence of nephrocalcinosis in one case. Screening by Whole Exome Sequencing (WES) and long range PCR revealed that 12/17 patients (70%) had a deletion of the entire CLCNKB gene that was previously identified as the most common cause of Bartter Syndrome in other populations. 4/17 individuals (approximately 25% of cases) were found to suffer in fact from pseudo-Bartter syndrome resulting from congenital chloride diarrhea due to a novel homozygous mutation in the SLC26A3 gene, Pendred syndrome due to a known homozygous mutation in SLC26A4, Cystic Fibrosis (CF) due to a novel mutation in CFTR and apparent mineralocorticoid excess syndrome due to a novel homozygous loss of function mutation in HSD11B2 gene. 1 case (5%) remained unsolved. CONCLUSIONS: Our findings demonstrate deletion of CLCNKB is the most common cause of Bartter syndrome in Iranian patients and we show that age of onset of clinical symptoms as well as clinical features amongst those patients are variable. Further, using WES we were able to prove that nearly 1/4 patients in fact suffered from Pseudo-Bartter Syndrome, reversing the initial clinical diagnosis with important impact on the subsequent treatment and clinical follow up pathway. Finally, we propose an algorithm for clinical differential diagnosis of Bartter Syndrome

Influence of Rice Husk Ash on Crystalline Phases and Mechanical Characteristics of Sustainable Bricks

Abstract This study investigates the use of rice husk ash (RHA) as a sustainable additive in ceramic brick production. RHA from the Chaco region of Argentina was analyzed using DTA/TG and XRD, revealing a decrease in the amorphous phase and an increase in crystalline phases, mainly quartz and albite, with higher RHA content. The incorporation of RHA increased porosity from 25% to 40%, while theoretical density remained stable. Mechanical tests showed a decrease in elastic modulus (72.76 GPa for 5% RHA to 71.74 GPa for 15% RHA) and modulus of rupture (MOR) (8.5 MPa for 5% RHA to 5 MPa for 30% RHA). Several models were analyzed to predict the elastic modulus, and the DEM model provided the best predictions, with a relative error of 1.43% for 15% RHA. The analysis of mechanical properties of porosity was conducted using various theoretical models, which allowed for a better understanding of the relationship between the porous structure of the bricks and their mechanical behavior. Theoretical models, such as the DEM, proved effective in describing how porosity influences mechanical properties, particularly elastic modulus and modulus of rupture. Despite the reduction in mechanical properties, bricks with up to 15% RHA are suitable for non-structural applications, offering an eco-friendly alternative to conventional bricks. This research provides a circular economy approach by transforming agricultural waste into valuable construction materials

Mechanical and fracture behavior of insulating refractory bricks

Abstract Microstructure, texture, and mechanical and fracture characterization of three insulating commercial refractories were carried out in order to establish a correlation between these properties. The materials were characterized using X-ray powder diffraction (XRD) with Rietveld and Le Bail approximation to perform phase quantification, mercury intrusion porosimetry, and scanning electron microscopy. The mechanical behavior of insulating commercial refractories was studied with a multi-technique approach that involved a three-point bending test, uniaxial compression test, and single-edge notched beam (SENB) test. Stable fracture tests were successfully performed. The obtained results showed that the main differences between the materials studied were pore size distribution and mineralogical composition. Materials with the major amount of mullite had the highest values of the mechanical parameters in the different performed tests

Properties and homogeneity of a commercial light expanded clay aggregate

Abstract In the present work, an exhaustive analysis of an Argentinian commercial LECA with a multi-technique approach was successfully carried out. Five sub-types of samples were considered to study the degree of macroscopic homogeneity of the LECAs, which presented observable differences in color and morphology. The microstructural, textural, and mineralogical features of the aggregates within each category were assessed and the differences among them were described and discussed. The density values of the samples studied were between 1.01 and 1.20 g/cm3 and porosity percentages were in the range of 24 to 33 %. The samples present a similar mineralogical composition with quartz and anorthite as the main crystalline phases and almost 50 wt. % of non-crystalline phase. In addition, some variations in the Rietveld quantification were analyzed. The main challenge of LECAs industrial production is to control the raw materials and the process to obtain homogeneous LECAs with similar performance. In this regard, this type of analysis is useful for establishing and comparing some characterization strategies to control, select, design, and evaluate new LECAs

Severity of Giardia infection associated with post-infectious fatigue and abdominal symptoms two years after

<p>Abstract</p> <p>Background</p> <p>A high rate of post-infectious fatigue and abdominal symptoms two years after a waterborne outbreak of giardiasis in Bergen, Norway in 2004 has previously been reported. The aim of this report was to identify risk factors associated with such manifestations.</p> <p>Methods</p> <p>All laboratory confirmed cases of giardiasis (n = 1262) during the outbreak in Bergen in 2004 received a postal questionnaire two years after. Degree of post-infectious abdominal symptoms and fatigue, as well as previous abdominal problems, was recorded. In the statistical analyses number of treatment courses, treatment refractory infection, delayed education and sick leave were used as indices of protracted and severe <it>Giardia </it>infection. Age, gender, previous abdominal problems and symptoms during infection were also analysed as possible risk factors. Simple and multiple ordinal logistic regression models were used for the analyses.</p> <p>Results</p> <p>The response rate was 81% (1017/1262), 64% were women and median age was 31 years (range 3-93), compared to 61% women and 30 years (range 2-93) among all 1262 cases. Factors in multiple regression analysis significantly associated with abdominal symptoms two years after infection were: More than one treatment course, treatment refractory infection, delayed education, bloating and female gender. Abdominal problems prior to <it>Giardia </it>infection were not associated with post-infectious abdominal symptoms. More than one treatment course, delayed education, sick leave more than 2 weeks, and malaise at the time of infection, were significantly associated with fatigue in the multiple regression analysis, as were increasing age and previous abdominal problems.</p> <p>Conclusion</p> <p>Protracted and severe <it>giardiasis </it>seemed to be a risk factor for post-infectious fatigue and abdominal symptoms two years after clearing the <it>Giardia </it>infection.</p

Not gods but animals : human dignity and vulnerable subjecthood

Drawing on earlier work on the conceptual structure of dignity, this paper will suggest a particular type of connectedness between vulnerability and human dignity; namely, that the ‘‘organizing idea’’ of human dignity is the idea of a particular sort of ethical response to universal human vulnerability. It is common ground among many, if not all, approaches to ethics that vulnerability requires us to respond ethically. Here, I argue that human dignity is distinctive among ethical values in that it values us because of, rather than in spite of, or regardless of, our universal vulnerability. The term ‘‘dignity’’ is used synonymously with ‘‘human dignity’’ here, since an investigation of the dignity of non-human entities forms no part of the present examination

A critical analysis of the efficacy of law as a tool to achieve gender equality and to address the problem of domestic violence : The case of Trinidad and Tobago

Law is often perceived as an instrument that can effect social change. National law in Trinidad and Tobago, prima facie providing for gender equality, does not fully contemplate issues of particular concern to women, such as domestic violence. Gender equality and domestic violence are unwitting partners as women cannot achieve the former without first addressing the latter. Additionally, problems such as male dominance in politico-legal structures and lack of political will create practical obstacles to the realisation of gender equality and/or the full potential of the law. A case study of Trinidad and Tobago shows that the achievement of legal advances for women is particularly difficult where practical measures are not implemented domestically. Honouring international commitments subsequently becomes problematic as they do not guarantee change nationally and they, too, are sidelined. Gender equality and domestic violence are not given priority domestically and laws aimed towards protecting women and women’s rights are ineffective, scant and/or not enforced. The only way to achieve gender equality is through a multilevel approach from above (the UN) and, perhaps, more importantly, from below, as women have the potential to effect real national and international legal and institutional change to ensure gender equality at both levels.EThOS - Electronic Theses Online ServiceGBUnited Kingdo