Dissolution Kinetics of Stilbite at Various Temperatures under Alkaline Conditions

Experiments measuring the dissolution rates of stilbite (NaCa [Al Si O ].14H O) in pH-buffered solutions were 2 5 13 36 2 performed in batch reactors at 4, 25, 40 and 60 oC. The pH conditions of the buffer solutions ranged from 8.5 to 12.5. The dissolution rates calculated from silicon concentration of the reacting fluid increased with increasing temperature (4–60 oC) and pH. The dissolution rates ranged from 3.45 x 10-15 (mol cm-2 s-1) at pH 10.7 and 4oC to 1.93 x 10-9 (mol cm-2 s-1) at pH 12 and 60oC and were pH dependent. The rate law was established as R = k (a -)n , where k is OH the rate constant, a is the activity of the OH- species and n the reaction order. The n values obtained were, 0.32 at 4 oC, 0.35 at 25 oC, 0.38 at 40 oC and 0.38 at 60 oC. Activation energy determined using Arrhenius plot was 48.45 kJ/mol at pH 9 and 30.88 kJ/mol at pH 12

Calibration and Performance Testing of Sodium Iodide, NaI (Tl), Detector at the Food and Environmental Laboratory of the Radiation Protection Institute of the Ghana Atomic Energy Commission

The performance testing of a newly acquired sodium iodide detector (NaI), (Tl)) at Ghana Atomic Energy Commission (GAEC) was investigated by carrying out energy and efficiency calibration on the detector, as well as validation of its calibration. The energy and efficiency calibrations were performed using mixed radionuclides 241 109 57 137 60 standard containing Am, Cd, Co, Cs and Co in the energy range of 60–1333 keV. The energy and efficiency calibration curves obtained compare well with what is available in the literature. Results of the validation of the calibration showed that there were no significance differences between the measured and the calculated activities of the standard radionuclides with activity ratios in the range of 0.90-0.98 and the corresponding percentage deviation in a range of 1.43–10.47%. The average MDA of 238U, 232Th, 40K and 137Cs from background counting rates were estimated to be 0.099 ± 0.055 Bq, 0.061 ± 0.037 Bq, 0.727 ± 0.300 Bq and 0.014 ± 0.006 Bq, respectively

Artificial and Natural Radioactivity Measurements and Radiation Dose Assessment in the Vicinity of Ghana Nuclear Research Reactor-1 (GHARR-1)

Radioactivity concentrations of <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K and <sup>137</sup>Cs in soil samples and water sources around the Ghana Research Reactor-1 (GHARR-1) and the immediate surroundings have been measured using gamma spectrometry. The primary aim of the study was to establish baseline radioactivity levels in the environs of GHARR-1. The average activity concentration of <sup>226</sup>Ra, <sup>232</sup>Th, <sup>40</sup>K and <sup>137</sup>Cs were 22.3 ± 1.12 Bq kg<sup>-1</sup>, 49.8 ± 1.60Bq kg-1, 99.60 ± 5.81 Bq kg<sup>-1</sup> and 1.48 ± 0.25 Bq kg<sup>-1</sup> for soil and 0.60 ± 0.11 Bq l<sup>-1</sup>, 2.13 ± 0.21 Bq l<sup>-1</sup>, 10.75 ± 0.84 Bq l<sup>-1</sup> and 0.47 ± 0.05 Bq l<sup>-1</sup>for the water, respectively. The <sup>226</sup>Ra and <sup>232</sup>Th concentrations compare quite well with world averages, whilst the <sup>40</sup>K concentration was lower than the world average. The levels of <sup>137</sup>Cs observed in the samples are within the range of ‘background’  concentrations. The estimated average annual effective doses from external exposure to soil and ingestion of water samples were calculated to be 0.06 mSv and 0.53 mSv, respectively. The estimated outdoor  external gamma dose rate measured in air ranged from 20-430 nGy h<sup>-1</sup> with an average value of 100 nGy h<sup>-1</sup>, which is higher than the world average value of 59 nGy h<sup>-1</sup>. In the case of water samples, the average value was higher than the guidance level of 0.1 mSv y<sup>-1</sup>, as recommended by the European Union and the World Health Organization

The disruption of proteostasis in neurodegenerative diseases

Cells count on surveillance systems to monitor and protect the cellular proteome which, besides being highly heterogeneous, is constantly being challenged by intrinsic and environmental factors. In this context, the proteostasis network (PN) is essential to achieve a stable and functional proteome. Disruption of the PN is associated with aging and can lead to and/or potentiate the occurrence of many neurodegenerative diseases (ND). This not only emphasizes the importance of the PN in health span and aging but also how its modulation can be a potential target for intervention and treatment of human diseases.info:eu-repo/semantics/publishedVersio

Mammalian cell transfection: the present and the future

Transfection is a powerful analytical tool enabling study of the function of genes and gene products in cells. The transfection methods are broadly classified into three groups; biological, chemical, and physical. These methods have advanced to make it possible to deliver nucleic acids to specific subcellular regions of cells by use of a precisely controlled laser-microcope system. The combination of point-directed transfection and mRNA transfection is a new way of studying the function of genes and gene products. However, each method has its own advantages and disadvantages so the optimum method depends on experimental design and objective

4D cardiovascular magnetic resonance velocity mapping of alterations of right heart flow patterns and main pulmonary artery hemodynamics in tetralogy of Fallot

<p>Abstract</p> <p>Background</p> <p>To assess changes in right heart flow and pulmonary artery hemodynamics in patients with repaired Tetralogy of Fallot (rTOF) we used whole heart, four dimensional (4D) velocity mapping (VM) cardiovascular magnetic resonance (CMR).</p> <p>Methods</p> <p>CMR studies were performed in 11 subjects with rTOF (5M/6F; 20.1 ± 12.4 years) and 10 normal volunteers (6M/4F; 34.2 ± 13.4 years) on clinical 1.5T and 3.0T MR scanners. 4D VM-CMR was performed using PC VIPR (Phase Contrast Vastly undersampled Isotropic Projection Reconstruction). Interactive streamline and particle trace visualizations of the superior and inferior vena cava (IVC and SVC, respectively), right atrium (RA), right ventricle (RV), and pulmonary artery (PA) were generated and reviewed by three experienced readers. Main PA net flow, retrograde flow, peak flow, time-to-peak flow, peak acceleration, resistance index and mean wall shear stress were quantified. Differences in flow patterns between the two groups were tested using Fisher's exact test. Differences in quantitative parameters were analyzed with the Kruskal-Wallis rank sum test.</p> <p>Results</p> <p>4D VM-CMR was successfully performed in all volunteers and subjects with TOF. Right heart flow patterns in rTOF subjects were characterized by (a) greater SVC/IVC flow during diastole than systole, (b) increased vortical flow patterns in the RA and in the RV during diastole, and (c) increased helical or vortical flow features in the PA's. Differences in main PA retrograde flow, resistance index, peak flow, time-to-peak flow, peak acceleration and mean wall shear stress were statistically significant.</p> <p>Conclusions</p> <p>Whole heart 4D VM-CMR with PC VIPR enables detection of both normal and abnormal right heart flow patterns, which may allow for comprehensive studies to evaluate interdependencies of post-surgically altered geometries and hemodynamics.</p

Parenting after a history of childhood maltreatment: a scoping review and map of evidence in the perinatal period

BACKGROUND AND AIMS:Child maltreatment is a global health priority affecting up to half of all children worldwide, with profound and ongoing impacts on physical, social and emotional wellbeing. The perinatal period (pregnancy to two years postpartum) is critical for parents with a history of childhood maltreatment. Parents may experience 'triggering' of trauma responses during perinatal care or caring for their distressed infant. The long-lasting relational effects may impede the capacity of parents to nurture their children and lead to intergenerational cycles of trauma. Conversely, the perinatal period offers a unique life-course opportunity for parental healing and prevention of child maltreatment. This scoping review aims to map perinatal evidence regarding theories, intergenerational pathways, parents' views, interventions and measurement tools involving parents with a history of maltreatment in their own childhoods. METHODS AND RESULTS:We searched Medline, Psychinfo, Cinahl and Embase to 30/11/2016. We screened 6701 articles and included 55 studies (74 articles) involving more than 20,000 parents. Most studies were conducted in the United States (42/55) and involved mothers only (43/55). Theoretical constructs include: attachment, social learning, relational-developmental systems, family-systems and anger theories; 'hidden trauma', resilience, post-traumatic growth; and 'Child Sexual Assault Healing' and socioecological models. Observational studies illustrate sociodemographic and mental health protective and risk factors that mediate/moderate intergenerational pathways to parental and child wellbeing. Qualitative studies provide rich descriptions of parental experiences and views about healing strategies and support. We found no specific perinatal interventions for parents with childhood maltreatment histories. However, several parenting interventions included elements which address parental history, and these reported positive effects on parent wellbeing. We found twenty-two assessment tools for identifying parental childhood maltreatment history or impact. CONCLUSIONS:Perinatal evidence is available to inform development of strategies to support parents with a history of child maltreatment. However, there is a paucity of applied evidence and evidence involving fathers and Indigenous parents.Catherine Chamberlain, Graham Gee, Stephen Harfield, Sandra Campbell, Sue Brennan, Yvonne Clark, Fiona Mensah, Kerry Arabena, Helen Herrman, Stephanie Brown, for the ‘Healing the Past by Nurturing the Future’ grou

An adjustable sample average approximation algorithm for the stochastic production-inventory-routing problem

We consider a stochastic single item production-inventory-routing problem with a single producer, multiple clients, and multiple vehicles. At the clients, demand is allowed to be backlogged incurring a penalty cost. Demands are considered uncertain. A recourse model is presented, and valid inequalities are introduced to enhance the model. A new general approach that explores the sample average approximation (SAA) method is introduced. In the sample average approximation method, several sample sets are generated and solved independently in order to obtain a set of candidate solutions. Then, the candidate solutions are tested on a larger sample, and the best solution is selected among the candidates. In contrast to this approach, called static, we propose an adjustable approach that explores the candidate solutions in order to identify common structures. Using that information, part of the first-stage decision variables is fixed, and the resulting restricted problem is solved for a larger size sample. Several heuristic algorithms based on the mathematical model are considered within each approach. Computational tests based on randomly generated instances are conducted to test several variants of the two approaches. The results show that the new adjustable SAA heuristic performs better than the static one for most of the instances.publishe

The Neurotrophic Receptor Ntrk2 Directs Lymphoid Tissue Neovascularization during Leishmania donovani Infection

The neurotrophic tyrosine kinase receptor type 2 (Ntrk2, also known as TrkB) and its ligands brain derived neurotrophic factor (Bdnf), neurotrophin-4 (NT-4/5), and neurotrophin-3 (NT-3) are known primarily for their multiple effects on neuronal differentiation and survival. Here, we provide evidence that Ntrk2 plays a role in the pathologic remodeling of the spleen that accompanies chronic infection. We show that in Leishmania donovani-infected mice, Ntrk2 is aberrantly expressed on splenic endothelial cells and that new maturing blood vessels within the white pulp are intimately associated with F4/80hiCD11bloCD11c+ macrophages that express Bdnf and NT-4/5 and have pro-angiogenic potential in vitro. Furthermore, administration of the small molecule Ntrk2 antagonist ANA-12 to infected mice significantly inhibited white pulp neovascularization but had no effect on red pulp vascular remodeling. We believe this to be the first evidence of the Ntrk2/neurotrophin pathway driving pathogen-induced vascular remodeling in lymphoid tissue. These studies highlight the therapeutic potential of modulating this pathway to inhibit pathological angiogenesis

Effects of Different Correlation Metrics and Preprocessing Factors on Small-World Brain Functional Networks: A Resting-State Functional MRI Study

Graph theoretical analysis of brain networks based on resting-state functional MRI (R-fMRI) has attracted a great deal of attention in recent years. These analyses often involve the selection of correlation metrics and specific preprocessing steps. However, the influence of these factors on the topological properties of functional brain networks has not been systematically examined. Here, we investigated the influences of correlation metric choice (Pearson's correlation versus partial correlation), global signal presence (regressed or not) and frequency band selection [slow-5 (0.01–0.027 Hz) versus slow-4 (0.027–0.073 Hz)] on the topological properties of both binary and weighted brain networks derived from them, and we employed test-retest (TRT) analyses for further guidance on how to choose the “best” network modeling strategy from the reliability perspective. Our results show significant differences in global network metrics associated with both correlation metrics and global signals. Analysis of nodal degree revealed differing hub distributions for brain networks derived from Pearson's correlation versus partial correlation. TRT analysis revealed that the reliability of both global and local topological properties are modulated by correlation metrics and the global signal, with the highest reliability observed for Pearson's-correlation-based brain networks without global signal removal (WOGR-PEAR). The nodal reliability exhibited a spatially heterogeneous distribution wherein regions in association and limbic/paralimbic cortices showed moderate TRT reliability in Pearson's-correlation-based brain networks. Moreover, we found that there were significant frequency-related differences in topological properties of WOGR-PEAR networks, and brain networks derived in the 0.027–0.073 Hz band exhibited greater reliability than those in the 0.01–0.027 Hz band. Taken together, our results provide direct evidence regarding the influences of correlation metrics and specific preprocessing choices on both the global and nodal topological properties of functional brain networks. This study also has important implications for how to choose reliable analytical schemes in brain network studies