Small-angle neutron scattering and Molecular Dynamics structural study of gelling DNA nanostars

DNA oligomers with properly designed sequences self-assemble into well defined constructs. Here, we exploit this methodology to produce bulk quantities of tetravalent DNA nanostars (each one composed by 196 nucleotides) and to explore the structural signatures of their aggregation process. We report small-angle neutron scattering experiments focused on the evaluation of both the form factor and the temperature evolution of the scattered intensity at a nano star concentration where the system forms a tetravalent equilibrium gel. We also perform molecular dynamics simulations of one isolated tetramer to evaluate the form factor theoretically, without resorting to any approximate shape. The numerical form factor is found to be in very good agreement with the experimental one. Simulations predict an essentially temperature independent form factor, offering the possibility to extract the effective structure factor and its evolution during the equilibrium gelation.Comment: 9 pages, 5 figure

The association between HIV tri-therapy with the development of Type-2 Diabetes Mellitus in a rural South African District: A case-control study

BackgroundCombination antiretroviral drugs (cARVs) prolong patients' lives but are unfortunately thought to increase complications related to metabolic disorders including type-2 Diabetes Mellitus (DM). We sought to confirm the association of cARVs with type-2 DM and ascertain the extent of this association in a rural South African setting.MethodsA case-control study of 177 (33.33%) cases with HIV/AIDS and type-2 DM were selected and compared with 354 (66.67%) non-DM HIV/AIDS unmatched controls from a rural district of South Africa's third most populous province (Eastern Cape). Cases were identified from community health centres using the district health information system, and controls were identified using simple random sampling from the same health facilities. Odds Ratios (OR), together with 95% confidence intervals, were calculated for all the univariable and multivariable logistic analyses.ResultsThis study found that cARVs significantly increased the occurrence of type-2 DM among HIV patients. Patients on protease inhibitors (PIs) were at least 21 times significantly (pConclusionThis study has been able to establish the association between cARVs and type-2 DM. It therefore proposes consideration of the usage of AZT, D4T, lopivavir and ritonavir for the treatment of HIV. The study further proposes more prospective research to test these findings further

Sustainable development and African local government: can electronic training help build capacities?

A recent study carried out by European and African organizations into the potential for electronic distance training (EDT) on sustainability in African local governments concluded that EDT was both 'useful and feasible'. This article reflects on some of the theoretical and practical implications of that study. It focuses on the connection between learning and sustainability and how EDT programmes might be designed and promoted. The paper argues that, while resource issues and poor access to Information and Communication Technologies (ICTs) create considerable constraints and point to the need for policies to improve access, in general the most important factors for successful capacity building relate to the design of learning programmes that take account of the work contexts and skill and capability requirements of those targeted as learners. 'Useful' and 'feasible' depend on (i) how work-based and work-related learning processes are understood and (ii) the conditions to promote learning within African local government. Keywords: Africa; Electronic distance training; Local government; Sustainability; Workplace learnin

The impact of physician education regarding the importance of providing complete clinical information on the request forms of thrombophilia-screen tests at Tygerberg hospital in South Africa

CITATION: Abdullah, I., Jafta, A. D. & Chapanduka, Z. C. 2020. The impact of physician education regarding the importance of providing complete clinical information on the request forms of thrombophilia-screen tests at Tygerberg hospital in South Africa. PLoS ONE, 15(8):e0235826, doi:10.1371/journal.pone.0235826.The original publication is available at https://journals.plos.org/plosone/Publication of this article was funded by the Stellenbosch University Open Access FundBackground: Thrombophilia-screen tests are specialised haemostasis tests that are affected by numerous unique patient variables including the presence of acute thrombosis, the concomitant use of medication and patient demographics. Complete information on the request form is therefore crucial for the haematological pathologist to make patient-specific interpretation of patients’ results. Objectives: To assess the completeness of thrombophilia-screen test request forms and determine the impact of provision of incomplete information, on the interpretive comments generated by reporting haematological pathologists. To assess the impact of an educational session given to clinicians on the importance of providing all the relevant information on the request forms. Method: Two retrospective audits, each covering 3 months, were performed to evaluate the completeness of demographic and clinical information on thrombophilia-screen request forms and its impact on the quality of the interpretive comments before and after an educational intervention. Results: One hundred and seventy-one request forms were included in the first audit and 146 in the second audit. The first audit revealed that all 171 thrombophilia-screen request forms had complete patient demographic information but none had clinical information. Haematological pathologists only made generic comments which could not be applied to a specific patient. The second audit, conducted after a physician educational session, did not reveal any improvement in the clinical information provision by the test-ordering physicians. This was reportedly due to the lack of space on the request form. The interpretive comments therefore remained generic and not patient-specific. Conclusion: Physicians’ failure to provide relevant clinical information made it impossible for pathologists to make patient-specific interpretation of the results. A single physician education session did not change the practice, reportedly due to the inappropriate design of the test request form. Further studies are required to investigate the impact of an improved request form and the planned electronic test requesting.https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0235826Publisher's versio

Microwave Irradiation Controls the Manganese Oxidation States of Nanostructured Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O 2 Layered Cathode Materials for High Performance Lithium Ion Batteries

A hybrid synthesis procedure, combining microwave irradiation and conventional annealing process, is described for the preparation of lithium-rich manganese-rich cathode materials, Li[Li0.2Mn0.54Ni0.13Co0.13]O2 (LMNC) and its aluminum-doped counterpart, Li[Li0.2Mn0.52Ni0.13Co0.13Al0.02]O2 (LMNCA). Essentially, this study interrogates the structure and electrochemistry of these layered cathode materials when subjected to microwave irradiation (these microwave-based produced are abbreviated herein as LMNC-mic andLMNCA-mic). The nanoparticulate nature of these layered cathode materials were confirmed by SEM. The crystallinity and layeredness were determined from the XRD analysis. The XPS measurements proved a definite change in the oxidation states of the manganese due to microwave irradiation. The galvanostatic charge-discharge characterization showed that the aluminum-doped cathode material obtained with the assistance of microwave irradiation has superior electrochemical properties. In summary, the electrochemical performance of these cathode materials produced with and without the assistance of microwave irradiation decreased as follows: LMNCAmic > LMNCA > LMNCmic > LMNC.CSIR, South Africa’s Department of Science and Technology (DST) and National Research Foundation (NRF) under the “Nanotechnology Flagship Programme” (Grant No: 69849).http://jes.ecsdl.orghb201

Mesoscopic structural organization in fluorinated room temperature ionic liquids

The presence of fluorous tails in room-temperature ionic liquids imparts new properties to their already rich spectrum of appealing features. The interest towards this class of compounds that are of ionic nature with melting point less than 25 °C is accordingly growing; in particular, compounds bearing relatively long fluorous tails have begun to be considered. In this invited presentation, we show recent results arising from the systematic study of structural properties of a series of fluorinated room temperature ionic liquids, with growing fluorous chain length. At odd with the current understanding of this class of compounds, we show experimentally that they are characterized by the presence of segregated fluorous domains whose size depends on the fluorous chain length. This experimental finding, based on the synergic use of X-ray and neutron scattering, provides a structural scenario at the mesoscopic spatial scale that is in agreement with the recent state of the art molecular dynamic simulations. We speculate on the potential role of this significant compartmentalization of the bulk liquid phase into different nanoscale domains, as relevant in a series of applications including separation, solubility, catalysis, and so forth