Journal of African Christian Biography: v. 5, no. 2

A publication of the Dictionary of African Christian Biography with U.S. offices located at the Center for Global Christianity and Mission at Boston University. This issue focuses on: Women / Bilingual (French): 1. Biography of Émilienne Mboungou-Mouyabi (née Niangui Loubota), Congolese woman pastor, in ENGLISH and in FRENCH; 2. "Recovering the Lives of African Women Leaders in South Africa: The Case of Nokutela Dube" By Heather Hughes, chapter from African Christian Biography: Stories, Lives and Challenges, (D. L. Robert, editor); 3. "Notes on the Life History of the Reverend Canon Professor Emeritus John Samuel Pobee (1937 to 2020)"" by Casely Essamuah.; and, 4. "Theological Publishing and the Future of Christianity in Africa: African Theological Network Press" by Kyama Mugambi. 5. Book Notes, by Beth Restrick

Deformation-resembling microstructure created by fluid-mediated dissolution-precipitation reactions

Deformation microstructures are widely used for reconstructing tectono-metamorphic events recorded in rocks. In crustal settings deformation is often accompanied and/or succeeded by fluid infiltration and dissolution–precipitation reactions. However, the microstructural consequences of dissolution–precipitation in minerals have not been investigated experimentally. Here we conducted experiments where KBr crystals were reacted with a saturated KCl-H2O fluid. The results show that reaction products, formed in the absence of deformation, inherit the general crystallographic orientation from their parents, but also display a development of new microstructures that are typical in deformed minerals, such as apparent bending of crystal lattices and new subgrain domains, separated by low-angle and, in some cases, high-angle boundaries. Our work suggests that fluid-mediated dissolution–precipitation reactions can lead to a development of potentially misleading microstructures. We propose a set of criteria that may help in distinguishing such microstructures from the ones that are created by crystal-plastic deformation

Neutron powder diffraction study on the iron-based nitride superconductor ThFeAsN

We report neutron diffraction and transport results on the newly discovered superconducting nitride ThFeAsN with $T_c=$ 30 K. No magnetic transition, but a weak structural distortion around 160 K, is observed cooling from 300 K to 6 K. Analysis on the resistivity, Hall transport and crystal structure suggests this material behaves as an electron optimally doped pnictide superconductors due to extra electrons from nitrogen deficiency or oxygen occupancy at the nitrogen site, which together with the low arsenic height may enhance the electron itinerancy and reduce the electron correlations, thus suppress the static magnetic order.Comment: 4 pages, 4 figures, Accepted by EP

The impact of education in shaping lives: reflections of young people with disabilities in Ghana

There is increasing recognition on the importance of focusing on people with disabilities in international efforts aimed at poverty alleviation. While universal education has been central to these efforts, the specific and additional needs of children with disabilities are often overlooked in policies and programmes. In order to gain a nuanced appreciation of the lives of young people with disabilities in a Ghanaian context, this paper draws on research conducted with young people with disabilities and their significant others in order to understand their educational journeys, employment prospects and perceptions of those around them. In addition to collecting primary data, the latest policy documents related to disability, education and employment are reviewed and statistical analysis undertaken based on the Housing and Population Census 2010. Our research highlights the barriers facing those with disability in accessing quality education. While education was recognised as paramount to leading a better life and participants noted benefits beyond employment such as gaining self-sufficiency and social benefits, unequal educational opportunities underpin some of the reasons for the widening of gaps between those with disabilities and their non-disabled counterparts. Furthermore, while education was seen as important for gaining employment, this was not the case in reality, as young people faced difficulties due to both physical and attitudinal barriers limiting their opportunities for economic and social participation in their communities. The paper concludes by noting that systematic changes in the policy arena are needed to enable youth with disabilities to take their rightful place in mainstream society.This is the accepted author manuscript. The final version is available at http://www.tandfonline.com/doi/abs/10.1080/13603116.2015.1018343

Carbon monoxide and carbon dioxide insertion chemistry of f-block <em>N</em>-heterocyclic carbene complexes

The reactions of f-block silylamido N-heterocyclic carbene (NHC) complexes ([M(L)(N{SiMe3}2)2], M = Y, Ce, and U, L = bidentate alkoxy-tethered NHC ligand) with CO and CO2 have been studied and compared to each other, to those of selected [M(L)2 (N{SiMe3}2)] complexes, and to those of [M(N{SiMe3}2)3] to identify the effect of the labile NHC group on the small molecule activation chemistry. The small molecules COS and N2CPh2 have also been studied.</p

Caffeine affects the biological responses of human hematopoietic cells of myeloid lineage via downregulation of the mTOR pathway and xanthine oxidase activity

Correction of human myeloid cell function is crucial for the prevention of inflammatory and allergic reactions as well as leukaemia progression. Caffeine, a naturally occurring food component, is known to display anti-inflammatory effects which have previously been ascribed largely to its inhibitory actions on phosphodiesterase. However, more recent studies suggest an additional role in affecting the activity of the mammalian target of rapamycin (mTOR), a master regulator of myeloid cell translational pathways, although detailed molecular events underlying its mode of action have not been elucidated. Here, we report the cellular uptake of caffeine, without metabolisation, by healthy and malignant hematopoietic myeloid cells including monocytes, basophils and primary acute myeloid leukaemia mononuclear blasts. Unmodified caffeine downregulated mTOR signalling, which affected glycolysis and the release of pro-inflammatory/pro-angiogenic cytokines as well as other inflammatory mediators. In monocytes, the effects of caffeine were potentiated by its ability to inhibit xanthine oxidase, an enzyme which plays a central role in human purine catabolism by generating uric acid. In basophils, caffeine also increased intracellular cyclic adenosine monophosphate (cAMP) levels which further enhanced its inhibitory action on mTOR. These results demonstrate an important mode of pharmacological action of caffeine with potentially wide-ranging therapeutic impact for treating non-infectious disorders of the human immune system, where it could be applied directly to inflammatory cells

A co-crystal between benzene and ethane: a potential evaporite material for Saturn’s moon Titan

Using synchrotron X-ray powder diffraction, the structure of a co-crystal between benzene and ethane formed in situ at cryogenic conditions has been determined, and validated using dispersion-corrected density functional theory calculations. The structure comprises a lattice of benzene molecules hosting ethane molecules within channels. Similarity between the intermolecular interactions found in the co-crystal and in pure benzene indicate that the C— H network of benzene is maintained in the co-crystal, however, this expands to accommodate the guest ethane molecules. The co-crystal has a 3:1 benzene:ethane stoichiometry and is described in the space group R3 with a = 15.977 (1) A˚ and c = 5.581 (1) A˚ at 90 K, with a density of 1.067 g cm3 . The conditions under which this co-crystal forms identify it is a potential that forms from evaporation of Saturn’s moon Titan’s lakes, an evaporite material

Medieval climate change and settlement in Iceland

A key issue in studies of Norse settlement in Iceland is the role that climate has played in shaping the history of the island. The thesis has two main objectives: (1) to constrain the timing and nature of any significant variations in climate during the Medieval period, and around the time of Norse settlement in Iceland (c.500-1500AD). (2) to evaluate likely impacts post-settlement of such changes upon those living in Iceland. To do this, the project uses a multidisciplinary approach, combining new empirical data, existing empirical and documentary data, and a new climate model for Iceland.Medieval glacier retreat was examined using lacustrine sediment sequences collected from two localities, that from SkeiSsvatn in Trollaskagi being notable as of being at least 1350 years in length. At Skeibsvatn, lacustrine evidence indicates the onset of Late Holocene glaciation around A.D. 650, and that glaciation of the catchment has continued uninterrupted to the present day. This constrains the warmth of the 'Medieval Warm Period', while terminal moraines constrain both 'Little Ice Age' and earlier Neoglacial advances. This is the first such lacustrine record of glacier retreat from Iceland.Two models are presented in the thesis, the most important being an original massbalance and vegetation cover model. The first modelling approach used is to apply the threedimensional ice sheet model GLIMMER to test the sensitivity of selected small glaciers to growth and disappearance. The second modelling approach was the construction of a new model of climate and vegetation for Iceland.The Iceland climate model is Java-based, and includes well over 12,000 lines of original code. It shows that it is possible to model monthly and annual vegetation limits, snowlines and snowcover based on inputs of primarily topography, temperature and precipitation, and constrain the modelling using glacier mass balance. This model has been used to evaluate spatial and temporal environmental responses to changes in temperature and precipitation of known magnitude, and to test the responses to long timeseries of temperature data.Integrated mass balance and ecological modelling combined with geomorphic data can be used to assess settlement changes in southern Iceland. Soil erosion in Thorsmork was not directly driven by climatic change, and the degradation has a land management origin. The solution, as shown in the preservation of woodlands in Thorsmork, was a land management decision, and not deterministically driven by a drop in temperature. Birch woodland in Thorsmork is at risk of removal during sustained colder spells, but the climatic impact on soil erosion is limited.Modelling of the Myvatn region indicates increased vulnerability of the landscape to environmental changes on the order of ±1°C, which are likely to trigger large changes in tree birch cover or good quality grazing land area. Growing season length is shortened by c.25%, and late-lying snowcover is an additional challenge in colder years. Response to warming is one of substantially reduced snowcover at lower elevations, and an inland shift of vegetation boundaries.Aeolian sediment sequences from Geithellnadalur, in combination with modelling data gives further insight into the relative importance of climate and human land management practices, and this can be used to identify threshold events. Geithellnadalur shows that environmental change in Iceland is not always directly related to climate, but that climate may have an indirect influence on landscape changes. Within the sediment accumulation record, evidence of both the impact of settlement and the impact of the Little Ice Age are visible.The new modelling approach, combined with the gathered empirical data, has provided key insights into the many different ways in which climate and environment interact over a varied topography, with consequently diverse effects upon settlement

Probing cytochrome P450-mediated activation with a truncated azinomycin analogue

YesA deactivated alkene precursor (IC50=81 mu M) to the azinomycin epoxide natural product can be bioactivated by several cytochromes P450 (CYP) to generate antiproliferative metabolites with increased potency (IC50=1-30 mu M) in CHOwt cells. CYP1A1 and 3A4 were shown to generate exclusively the unnatural and the natural-configured azinomycin epoxide diastereoisomer respectively, while CYP1B1 produced both epoxides in a 3:1 mixture. The antiproliferative activity is linked to DNA damage as demonstrated using the comet assay