Lithium hydroxide dihydrate: A new type of icy material at elevated pressure

We show that, in addition to the known monohydrate, LiOH forms a dihydrate at elevated pressure. The dihydrate involves a large number of H-bonds establishing chains along the direction. In addition, the energy surface exhibits a saddle point for proton locations along certain O interatomic distances, a feature characteristic for superprotonic conductors. However, MD simulations indicate that LiOH·2H_2O is not a superprotonic conductor and suggest the relevant interpolyhedral O–O distances being too large to allow for proton transfer between neighboring Li-coordinated polyhedra at least on the time scale of the MD-simulations

Diarrhea and Intestinal Parasites among HIV Infected Patients in Baringo, Kenya

Intestinal parasitic infection is one of the health threats in HIV positive patients especially in the developing countries and often presents clinically as diarrhea which further worsens the health status of the HIV patient who are already immunocompromised. This study was carried out to determine the association of intestinal parasites with diarrhea among HIV infected patients in Baringo County, Kenya. A cross-sectional study was carried out at the Baringo District hospital, AMPATH clinic. The ethical approval of the study was obtained from the Moi Teaching and Referral Hospital and Moi University Institutional Research and Ethical Committee (IREC). A total of 285 stool specimen of confirmed HIV infected patients was collected for laboratory screening for intestinal parasites. Chi-square (?2) statistical analysis was used to test level of significance at P = 0.05 using SPSS. A prevalence of 50.9% of intestinal parasites was recorded. There was an association (p<0.05) between intestinal parasitic infection and diarrhea, frequency of passing stool and stool consistency. Patients with diarrhea had a prevalence of 86.75% of intestinal parasitic infection. Parasites identified were Entamoeba histolytica/dispar (58.3%), Giardia lamblia (16.55%), Ascaris lumbricoides (8.6%), Entamoeba coli (5.96%), Taenia saginata (5.28%), Trichuris trichuria (1.98%), Enterobius vermicularis (1.97%) and hookworm (1.32%). Improving the quality of life of HIV infected patients can be achieved by early diagnosis for the intestinal parasites, often under-estimated in their role of causing morbidity. Keywords: Prevalence, Intestinal parasites, HIV, Diarrhea, Kenya

Compressibility of CeMIn5Ce M In_5 and Ce2MIn8Ce_2 M In_8 (M = Rh, Ir and Co) Compounds

The lattice parameters of the tetragonal compounds Ce$M$In$_{5}$ and Ce$_{2}M$In$_{8}$($M=$Rh, Ir and Co) have been studied as a function of pressure up to 15 GPa using a diamond anvil cell under both hydrostatic and quasihydrostatic conditions at room temperature. The addition of $M$In$_{2}$ layers to the parent CeIn$_{3}$ compound is found to stiffen the lattice as the 2-layer systems (average of bulk modulus values $B_{0}$ is 70.4 GPa) have a larger $B_{0}$ than CeIn$_{3}$ (67 GPa), while the 1-layer systems with the are even stiffer (average of $B_{0}$ is 81.4 GPa). Estimating the hybridization using parameters from tight binding calculations shows that the dominant hybridization is $fp$ in nature between the Ce and In atoms. The values of $V_{pf}$ at the pressure where the superconducting transition temperature $T_{c}$ reaches a maximum is the same for all Ce$M$In$_{5}$ compounds. By plotting the maximum values of the superconducting transition temperature $T_{c}$ versus $c/a$ for the studied compounds and Pu-based superconductors, we find a universal $T_{c}$ versus $c/a$ behavior when these quantities are normalized appropriately. These results are consistent with magnetically mediated superconductivity.Comment: Updated version resubmitted to Phys. Rev.

Multi-wavelength Bragg coherent X-ray diffraction imaging of Au particles

International audienceMulti-wavelength (mw) Bragg coherent X-ray diffraction imaging (BCDI) is demonstrated on a single Au particle. The multi-wavelength Bragg diffraction patterns are inverted using conventional phase-retrieval algorithms where the dilation of the effective pixel size of a pixelated 2D detector caused by the variation of the X-ray beam energy is mitigated by interpolating the raw data. The reconstructed Bragg electron density and phase field are in excellent agreement with the results obtained from conventional rocking scans of the same particle. Voxel sizes of about 6 3 nm 3 are obtained for reconstructions from both approaches. Phase shifts as small as 0.41 rad, which correspond to displacements of 14 pm and translate into strain resolution better than 10 À4 in the Au particle, are resolved. The displacement field changes shape during the experiment, which is well reproduced by finite element method simulations considering an inhomogeneous strained carbon layer deposited on the Au particle over the course of the measurements. These experiments thus demonstrate the very high sensitivity of BCDI and mw-BCDI to strain induced by contaminations. Furthermore, mw-BCDI offers new opportunities for in situ and operando 3D strain imaging in complex sample environments

Differentiation of two Botryosphaeriaceae species isolated from declining mango trees in Ghana

Lasiodiplodia theobromae is the only pathogen reported to cause mango tree decline disease in Ghana. In this study, several Botryosphaeriaceae isolates were obtained from mango tree decline disease symptoms and were identified using both phenotypic and genotypic characteristics and inoculation studies. The methods employed differentiated the isolates into two species, Lasiodiplodia theobromae and Neofussicoccum parvum. L. theobromae sporulated freely on media while N. parvum did not. Also, the species specific primer, Lt347-F/Lt347-R identified only L. theobromae while in the phylogenetic studies, L. theobromae and N. parvum clustered in different clades. L. theobromae caused dieback symptoms on inoculated mango seedlings while N. parvum did not. However, both species caused massive rot symptoms on inoculated fruits. L. theobromae was therefore confirmed as the causal agent of the tree decline disease in Ghana while N. parvum was reported for the first time as a potential pathogen of mango fruits in the country

The Aetiology, Incidence and Severity of Mango Tree Decline Disease in Ghana

Mango tree decline was previously an unknown disease in Ghana. In this study, mango trees from all the major agro-ecological zones of Ghana, where mangoes are grown were surveyed for the disease incidence, severity and aetiology of a similar disease affecting the crop. Farm visits were made to some selected farms within the selected agro-ecological zones and both the local and exotic trees were inspected. The percentage of infected trees were calculated while the severity of the disease was rated on a scale of 0-5, where 0 = no symptoms and 5 = death of trees. Samples of the diseased plant parts were collected and the causal agent was isolated on media and identified. The isolated fungus was tested for its pathogenicity using mango seedlings as test crops. The disease, characterised by profuse gumming, bark cracking and die back, was found to be present in all the agro-ecological zones. The disease incidence was higher on the local variety compared to the exotic varieties. Lasiodiplodia theobromae, isolated from the diseased plant parts, was able to cause the disease on inoculated mango seedlings. The nature of the disease symptoms and its causative agent in Ghana, confirms the disease as the mango tree decline disease

Ultra-low energy scattering of a He atom off a He dimer

We present a new, mathematically rigorous, method suitable for bound state and scattering processes calculations for various three atomic or molecular systems where the underlying forces are of a hard-core nature. We employed this method to calculate the binding energies and the ultra-low energy scattering phase shifts below as well as above the break-up threshold for the three He-atom system. The method is proved to be highly successful and suitable for solving the three-body bound state and scattering problem in configuration space and thus it paves the way to study various three-atomic systems, and to calculate important quantities such as the cross-sections, recombination rates etc.Comment: LaTeX, RevTeX and amssymb styles, 7 pages (25 Kb), 3 table

Localized f electrons in CexLa1-xRhIn5: dHvA Measurements

Measurements of the de Haas-van Alphen effect in CexLa1-xRhIn5 reveal that the Ce 4f electrons remain localized for all x, with the mass enhancement and progressive loss of one spin from the de Haas-van Alphen signal resulting from spin fluctuation effects. This behavior may be typical of antiferromagnetic heavy fermion compounds, inspite of the fact that the 4f electron localization in CeRhIn5 is driven, in part, by a spin-density wave instability.Comment: 4 pages, 4 figures, submitted to PR

In‐situ Bragg coherent X‐ray diffraction during tensile testing of an individual Au nanowire

Nanomechanical testing methods have drawn significant attention in both scientific and industrial research fields owing to unique deformation mechanisms in constrained volumes that underpin new property regimes. In-situ imaging equipment is now routinely employed to monitor the live evolution of material response during mechanical loading, with many of the testing developments tailored for electron microscopes (EMs). More recently, progress towards quantitative in-situ testing at synchrotron beamlines1–3 enabled by innovations in source brightness, focusing optics, and large size detectors has been made. Novel techniques such as Bragg coherent X-ray diffraction promise 3D information with phase information related to displacement fields (elastic strain, defects) within the material. However, despite the rich information that can be collected, many challenges arise in the realization of in-situ imaging of single nanostructures using such methods, including meticulous sample preparation and complex data analysis in retrieving phase information. In this work, we present the first successful systematic single nanowire tensile test while simultaneously recording 3D Bragg peaks using coherent X-rays. Defect free single crystalline \u3c110\u3e oriented Au nanowires were grown by physical vapor deposition4 and a 100 nm nanowire was harvested from the substrate and transferred to a nanotensile stage within a microelectromechanical system chip, which can be mounted to a coherent X-ray beamline. 3D Bragg peaks were recorded with nanofocused beam combined with 2D detector at each displacement step to discuss the evolution of strain and rotation of the nanowire during the tensile test. The movement of the peak sensitively depicted evolution of the deformation of the nanowire. In addition, the 3D Bragg coherent X-ray diffraction followed by phase retrieval has shown to reveal the internal strain state of nanostructure5 and this advanced technique is expected to reveal unique surface effects that mediate the overall mechanical performance of nano-scaled materials. 1. Cornelius, T. W. et al. In situ three-dimensional reciprocal-space mapping during mechanical deformation. J. Synchrotron Radiat. 19, 688–694 (2012). 2. Ren, Z. et al. Scanning force microscope for in situ nanofocused X-ray diffraction studies. J. Synchrotron Radiat. 21, 1128–1133 (2014). 3. Leclere, C. et al. In situ bending of an Au nanowire monitored by micro Laue diffraction. J. Appl. Crystallogr. 48, 291–296 (2015). 4. Richter, G. et al. Ultrahigh strength single crystalline nanowhiskers grown by physical vapor deposition. Nano Lett. 9, 3048–3052 (2009). 5. Haag, S. et al. Anomalous coherent diffraction of core-shell nano-objects: A methodology for determination of composition and strain fields. Phys. Rev. B 87, 35408 (2013)

A Fifteen-year Review of Lymphomas in a Nigerian Tertiary Healthcare Centre

In Africa, epidemiological data on the effect of the HIV epidemic on the occurrence of lymphomas are scanty. The 1990s witnessed the alarming rates of HIV/AIDS in Nigeria. The prevalence of HIV/AIDS in Nigeria increased from 1.8% in 1991 to 4.4% in 2005. The aim of this study was to determine whether there have been any changes in the frequency and pattern of lymphomas in view of the HIV/AIDS epidemic in the country. This is a retrospective study of all lymphoma cases diagnosed during 1991-2005. The prevalence of lymphomas declined from 1.4% to 0.7% of surgical biopsies during 1991-2005. There was a decline in the proportion of high-grade non-Hodgkin lymphoma and Burkitt's lymphoma from 79.1% and 45.8% respectively to 21.1% and 13.6% respectively. There is a suggestion that the HIV/AIDS epidemic in the country may not have influenced the pattern of occurrence of both major histomorphological types of lymphoma in Ibadan