Exploring water adsorption on isoelectronically doped graphene using alchemical derivatives

The design and production of novel 2-dimensional materials has seen great progress in the last decade, prompting further exploration of the chemistry of such materials. Doping and hydrogenating graphene is an experimentally realised method of changing its surface chemistry, but there is still a great deal to be understood on how doping impacts on the adsorption of molecules. Developing this understanding is key to unlocking the potential applications of these materials. High throughput screening methods can provide particularly effective ways to explore vast chemical compositions of materials. Here, alchemical derivatives are used as a method to screen the dissociative adsorption energy of water molecules on various BN doped topologies of hydrogenated graphene. The predictions from alchemical derivatives are assessed by comparison to density functional theory. This screening method is found to predict dissociative adsorption energies that span a range of more than 2 eV, with a mean absolute error $<0.1$ eV. In addition, we show that the quality of such predictions can be readily assessed by examination of the Kohn-Sham highest occupied molecular orbital in the initial states. In this way, the root mean square error in the dissociative adsorption energies of water is reduced by almost an order of magnitude (down to $\sim0.02$ eV) after filtering out poor predictions. The findings point the way towards a reliable use of first order alchemical derivatives for efficient screening procedures

Science-based health innovation in sub-Saharan Africa

In recent years emerging markets such as India, China, and Brazil have developed appropriate business models and lower-cost technological innovations to address health challenges locally and internationally. But it is not well understood what capabilities African countries, with their high disease burden, have in science-based health innovation

INVESTIGATION OF ALUMINUM TOXICITY AMONG WORKERS IN ALUMINUM INDUSTRY SECTOR

The study was conducted to evaluate urine aluminum concentration among a total of 150 participants (80 aluminum technicians and 70 non- aluminum technicians as a control). Data were collected through a previously prepared questionnaire which consists of two parts. The first part concerned with demographic data such as age and nationality. The second part concerned with occupational data such as working hours, working years, smoking, and diseases. The mean concentration of aluminum is 51.62+ 29.59 μg/l and the mean concentration of group control 16.32 + 12.49 μg/l. The following variables were associated significantly with aluminum concentration: age, weekly working hours, smoking and daily smoking packets.According to our study, aluminum workers have high concentrations of urine aluminum compared with other studies, in addition to that the incidence of diseases in relation to exposure is low, simply because: 1-Self reported questionnaires may be not a proper way to collect data about diseases. 2- Traditional surveillance approaches used in public health practice are difficult to apply to metals poisoning because adverse health effects related to metal exposure may not be clinically diagnosed, except at very high exposure levels, and are not usually listed as reportable diseases.Finally Special safety precautions and educational programs are also needed to limit the aluminum exposure in this industrial group

Science-based health innovation in Uganda: creative strategies for applying research to development

<p>Abstract</p> <p>Background</p> <p>Uganda has a long history of health research, but still faces critical health problems. It has made a number of recent moves towards building science and technology capacity which could have an impact on local health, if innovation can be fostered and harnessed.</p> <p>Methods</p> <p>Qualitative case study research methodology was used. Data were collected through reviews of academic literature and policy documents and through open-ended, face-to-face interviews with 30 people from across the science-based health innovation system, including government officials, researchers in research institutes and universities, entrepreneurs, international donors, and non-governmental organization representatives.</p> <p>Results</p> <p>Uganda has a range of institutions influencing science-based health innovation, with varying degrees of success. However, the country still lacks a coherent mechanism for effectively coordinating STI policy among all the stakeholders. Classified as a least developed country, Uganda has opted for exemptions from the TRIPS intellectual property protection regime that include permitting parallel importation and providing for compulsory licenses for pharmaceuticals. Uganda is unique in Africa in taking part in the Millennium Science Initiative (MSI), an ambitious though early-stage $30m project, funded jointly by the World Bank and Government of Uganda, to build science capacity and encourage entrepreneurship through funding industry-research collaboration. Two universities – Makerere and Mbarara – stand out in terms of health research, though as yet technology development and commercialization is weak. Uganda has several incubators which are producing low-tech products, and is beginning to move into higher-tech ones like diagnostics. Its pharmaceutical industry has started to create partnerships which encourage innovation.</p> <p>Conclusions</p> <p>Science-based health product innovation is in its early stages in Uganda, as are policies for guiding its development. Nevertheless, there is political will for the development of STI in Uganda, demonstrated through personal initiatives of the President and the government’s willingness to invest heavily for the long term in support of STI through the Millennium Science Initiative. Activities to support technology transfer and private-public collaboration have been put in motion; these need to be monitored, coordinated, and learned from. In the private sector, there are examples of incremental innovation to address neglected diseases driven by entrepreneurial individuals and South-South collaboration. Lessons can be learned from their experience that will help support Ugandan health innovation.</p

Spectrum of Paediatric Lysosomal Storage Disorders in Oman

Objectives: The aim of this study was to look at the spectrum of paediatric lysosomal disorders in Oman. Lysosomal storage disorders (LSDs) are a heterogeneous group of inherited metabolic diseases. Few studies on the birth prevalence and prevalence of LSDs have been reported from the Arabian Peninsula. Methods: We studied 86 children with LSDs diagnosed over a period of nine years, from June 1998 to May 2007. Detailed clinical data, including age of onset, sex, age and mode of first presentation, and presence of consanguinity were collected. Results: Our data showed the combined birth prevalence for all LSDs in Oman to be around 1 in 4,700 live births. Sphingolipidoses was the most common group of disorder encountered (47.7%), followed by neuronal ceroid lipofuscinoses (NCL) (23.2%) and mucopolysaccharidoses (MPS) (23.2%). The proportion of consanguineous marriages in our series was found to be 87.5%. Conclusion: Our data represent the birth prevalence and clinicalspectrum of such disorders in Oman, one of the highly consanguineous societies in the Middle East.

Penggunaan jenis-jenis penilaian oleh pensyarah dalam pengajaran dan pembelajaran di Jabatan Kejuruteraan Awam, Politeknik Ungku Omar

Penilaian ialah satu sistem atau proses yang meliputi aktiviti-aktiviti mengumpul maklumat tentang st'artegi dan aktiviti pengajaran dan pembelajaran, untuk membuat analisis dan keputusan denagn tujuan mengambil tindakan yang sewajamya seperti merancang aktiviti pengajaran dan pembelajaran selanjutnya dengan cara yang lebih berkesan. Penilaian terdiri daripada empat iaitu pra penempatan, formatif, diognastik dan sumatif. Keempat-empat jenis penilaian ini mempunyai kelebihan dan kelemahan yang tersendiri. Melalui dapatan kajian menunjukkan bahawa pensyarah lelaki lebih banyak menggunakan jenis-jenis penilaian dalam bilik kuliah iaitu min 3.37 berbanding dengan pensyarah perempuan iaitu min 3.28. Selain daripada itu, dapatan kajian juga menunjukkan sebanyak 47 % responden mempunyai pengetahuan tentang penilaian pendidikan jenis objektif, 6 4 % responden mengaplikasikan jenis penilaian kaedah lisan dalam aktiviti pengajaran dan 84 % responden bersetuju bahawa penilaian pendidikan telah dapat meningkatkan mutu diri pensyarah dalam aktiviti pengajaran. Manakala 2.7 % responden tidak bersetuju bahawa pelajar diberi masa yang mencukupi sebelum sesuatu jenis penilaian dilakukan. Sehubungan dengan itu pengkaji mencadangkan supaya pensyarah-pensyarah didedahkan dengan penggunaan jenis-jenis penilaian untuk meningkatkan keupayaan dan kecekapan dalam usaha membina jenis-jenis ujian dengan lebih bermutu. Pensyarah juga digalakkan untuk melakukan jenis-jenis penilaian dalam bilik kuliah. Selain daripada itu, pensyarah juga perlu memastikan pelajar sentiasa bersedia untuk dibuat penilaian. Seterusnya pensyarah perlu mempelbagaikan jenis-jenis penilaian pendidikan dalam aktiviti pengajaran bagi mengesan peringkat penguasaan dan kemajuan pelajar dalam semua bidang yang berkaitan dengan pendidika

Tuning dissociation using isoelectronically doped graphene and hexagonal boron nitride: water and other small molecules

Novel uses for 2-dimensional materials like graphene and hexagonal boron nitride (h-BN) are being frequently discovered especially for membrane and catalysis applications. Still however, a great deal remains to be understood about the interaction of environmentally and industrially elevant molecules such as water with these materials. Taking inspiration from advances in hybridising graphene and h-BN, we explore using density functional theory, the dissociation of water, hydrogen, methane, and methanol on graphene, h-BN, and their isoelectronic doped counterparts: BN doped graphene and C doped h-BN. We find that doped surfaces are considerably more reactive than their pristine counterparts and by comparing the reactivity of several small molecules we develop a general framework for dissociative adsorption. From this a particularly attractive consequence of isoelectronic doping emerges: substrates can be doped to enhance their reactivity specifically towards either polar or non-polar adsorbates. As such, these substrates are potentially viable candidates for selective catalysts and membranes, with the implication that a range of tuneable materials can be designed

Colorimetric Measurement of Triglycerides Cannot Provide an Accurate Measure of Stored Fat Content in Drosophila

Drosophila melanogaster has recently emerged as a useful model system in which to study the genetic basis of regulation of fat storage. One of the most frequently used methods for evaluating the levels of stored fat (triglycerides) in flies is a coupled colorimetric assay available as a kit from several manufacturers. This is an aqueous-based enzymatic assay that is normally used for measurement of mammalian serum triglycerides, which are present in soluble lipoprotein complexes. In this short communication, we show that coupled colorimetric assay kits cannot accurately measure stored triglycerides in Drosophila. First, they fail to give accurate readings when tested on insoluble triglyceride mixtures with compositions like that of stored fat, or on fat extracted from flies with organic solvents. This is probably due to an inability of the lipase used in the kits to efficiently cleave off the glycerol head group from fat molecules in insoluble samples. Second, the measured final products of the kits are quinoneimines, which absorb visible light in the same wavelength range as Drosophila eye pigments. Thus, when extracts from crushed flies are assayed, much of the measured signal is actually due to eye pigments. Finally, the lipoprotein lipases used in colorimetric assays also cleave non-fat glycerides. The glycerol backbones liberated from all classes of glycerides are measured through the remaining reactions in the assay. As a consequence, when these assay kits are used to evaluate tissue extracts, the observed signal actually represents the amount of free glycerols together with all types of glycerides. For these reasons, findings obtained through use of coupled colorimetric assays on Drosophila samples must be interpreted with caution. We also show here that using thin-layer chromatography to measure stored triglycerides in flies eliminates all of these problems

Microfluidics-based super-resolution microscopy enables nanoscopic characterization of blood stem cell rolling.

Hematopoietic stem/progenitor cell (HSPC) homing occurs via cell adhesion mediated by spatiotemporally organized ligand-receptor interactions. Although molecules and biological processes involved in this multistep cellular interaction with endothelium have been studied extensively, molecular mechanisms of this process, in particular the nanoscale spatiotemporal behavior of ligand-receptor interactions and their role in the cellular interaction, remain elusive. We introduce a microfluidics-based super-resolution fluorescence imaging platform and apply the method to investigate the initial essential step in the homing, tethering, and rolling of HSPCs under external shear stress that is mediated by selectins, expressed on endothelium, with selectin ligands (that is, CD44) expressed on HSPCs. Our new method reveals transient nanoscale reorganization of CD44 clusters during cell rolling on E-selectin. We demonstrate that this mechanical force-induced reorganization is accompanied by a large structural reorganization of actin cytoskeleton. The CD44 clusters were partly disrupted by disrupting lipid rafts. The spatial reorganization of CD44 and actin cytoskeleton was not observed for the lipid raft-disrupted cells, demonstrating the essential role of the spatial clustering of CD44 on its reorganization during cell rolling. The lipid raft disruption causes faster and unstable cell rolling on E-selectin compared with the intact cells. Together, our results demonstrate that the spatial reorganization of CD44 and actin cytoskeleton is the result of concerted effect of E-selectin-ligand interactions, external shear stress, and spatial clustering of the selectin ligands, and has significant effect on the tethering/rolling step in HSPC homing. Our new experimental platform provides a foundation for characterizing complicated HSPC homing

On the Sum Secrecy Rate of Multi-User Holographic MIMO Networks

The emerging concept of extremely-large holographic multiple-input multiple-output (HMIMO), beneficial from compactly and densely packed cost-efficient radiating meta-atoms, has been demonstrated for enhanced degrees of freedom even in pure line-of-sight conditions, enabling tremendous multiplexing gain for the next-generation communication systems. Most of the reported works focus on energy and spectrum efficiency, path loss analyses, and channel modeling. The extension to secure communications remains unexplored. In this paper, we theoretically characterize the secrecy capacity of the HMIMO network with multiple legitimate users and one eavesdropper while taking into consideration artificial noise and max-min fairness. We formulate the power allocation (PA) problem and address it by following successive convex approximation and Taylor expansion. We further study the effect of fixed PA coefficients, imperfect channel state information, inter-element spacing, and the number of Eve's antennas on the sum secrecy rate. Simulation results show that significant performance gain with more than 100\% increment in the high signal-to-noise ratio (SNR) regime for the two-user case is obtained by exploiting adaptive/flexible PA compared to the case with fixed PA coefficients.Comment: 7 pages, 7 figures, submitted to IEEE ICC 202