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Strain engineering of electro-optic constants in ferroelectric materials

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npj Computational Materials 2019年第1期5卷 1092-1096页

作者： charles paillard Sergei prokhorenko Laurent Bellaiche Department of physics and Institute for Nanoscience and Engineering University of ArkansasFayettevilleAR 72701USA

Electro-optic effects allow control of the ow of light using electric fields,and are of utmost importance for today’s information and communication technologies,such as TV displays and fiber *** search for large electro-optic constants in films is essential to the miniaturization and increased efficiency of electro-optic *** this work,we demonstrate that strain-engineering in pbTiO_(3) films allows to selectively choose which electro-optic constant to *** electro-optic constants larger than 100 pm V^(−1) are predicted,either by driving the softening of an optical phonon mode at a phase transition boundary under tensile strain,or by generating the equivalent of a negative pressure via compressive strain to obtain large piezoelectric *** particular,a r_(13) electro-optic coefficient twice as large as the one of the commonly used LiNbO_(3) electro-optic material is found here when growing pbTiO_(3) on the technologicallyimportant Si substrate.

关键词： softening constants ferroelectric

Institutional Structures and Sustainability of projects in Nyangores River Sub-Catchment Basin in Bomet County, Kenya

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Journal of Geoscience and Environment protection 2022年第12期10卷 331-353页

作者： Kirui Kipkorir charles Mallans Rambo George Muhua Faculty of Business and Management Sciences University of Nairobi Nairobi Kenya Faculty of Mathematics University of Nairobi Nairobi Kenya

Integrated basin management approach has been applied in Nyangores River sub-catchment basin, since the year 2009 but with minimal success. Sub catchment degradation, organizational weakness, the flow and quality of water had started to diminish, creating challenges for local livelihoods, wildlife in the Maasai Mara Game Reserve, and in maintaining biodiversity and healthy ecosystem functioning. Water resources can be successfully managed only if the natural, social, economic and political environments, in which water occurs and used, are taken fully into consideration. The aim of this study is to determine the influence of institutional structures influence on sustainability of projects in Nyagores river sub-catchment basin in Bomet County, Kenya. The research designs used were descriptive survey and correlational research design. Stepwise and purposive sampling formed the sampling procedure. The results are presented descriptively using Tables while for qualitative data, narrative statements were used. Questionnaires, Interview guide and document analysis were used for data collection. The sample size was 371, from a targeted a population of 56,508 household heads and 10 informants, purposively selected from the water concerned institutions and ministries of Water and Agriculture. Total of 371 questionnaires were given out to the respondents and only 321, were duly filled and returned representing (86.5%). The objective was to establish the extent to which institutional structures influence sustainability of projects in Nyangores River sub-catchment Basin. The results indicated that there was a positive correlation r = 0.552, (p is was rejected and concluded that there is a significant relationship between the institutional structures and sustainability of projects in Nyangores river sub-catchment basin. Rp>2p> was 0.304;hence, 30.4% of changes in sustainability of projects are explained by institutional structures. Recommendations are;ensure a stringent po

关键词： Institutional Structures Sustainability of projects River Sub-Catchment Basin

Vibrational Spectroscopic Investigations, Electronic properties, Molecular Structure and Quantum Mechanical Study of an Antifolate Drug: pyrimethamine

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Computational Chemistry 2022年第4期10卷 157-185页

作者： pélagie Manwal A Mekoung Bel Youssouf G. Mountessou Maraf B. Mbah Martin Signe Auguste Abouem A Zintchem charles p. N. Nanseu Ibrahim N. Mbouombouo Department of Inorganic Chemistry Faculty of Science University of Yaoundé I Yaoundé Cameroon Computational Chemistry Laboratory Department of Chemistry Higher Teacher Training College University of Yaoundé I Yaoundé Cameroon

The computational modelling supported by experimental results can explain the molecular structure, vibrational assignments, reactive sites and several structural properties. In this context, the spectroscopic (FT-IR, FT-Raman and NMR) analysis, electronic properties (HOMO and LUMO energies) and molecular structure of pyrimethamine (pyr) were investigated by density functional theory (DFT) method associated with three levels of theory viz., B3LYp, MN15 and wB97XD with 6-311++G(d,p) and def2TZVpp as basis sets, respectively in the Gaussian 16 programs. The p>1p>H and p>13p>C NMR chemical shifts were calculated with a gauge-independent atomic orbital (GIAO) approach by also applying the same levels of theory and basis sets. All experimental results were compared with theoretical data. Although the results revealed high degrees of correlation between the theoretical and experimental values for spectroscopic properties using the three methods. Furthermore, the atomic and natural charges, energy band gap and chemical reactivity were determined, while the frontier molecular orbital (FMO) and molecular electrostatic potential (MEp) surfaces were plotted to explain the reactive nature of the title molecule.

关键词： Electronic property NMR pyrimethamine Vibrational Spectrum

Formable porous biochar loaded with La-Fe(hydr)oxides/montmorillonite for efficient removal of phosphorus in wastewater:process and mechanisms

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Biochar 2022年第1期4卷 296-314页

作者： Enhui Sun Yanyang Zhang Qingbo Xiao Huayong Li ping Qu Cheng Yong Bingyu Wang Yanfang Feng Hongying Huang Linzhang Yang charles Hunter Key Laboratory of Saline-Alkali Soil Improvement and Utilization(Coastal Saline-Alkali Lands) Ministry of Agriculture and Rural AffairsJiangsu Collaborative Innovation Center for Solid Organic Waste Resource UtilizationInstitute of Agricultural Resources and EnvironmentJiangsu Academy of Agricultural SciencesNanjing 210014China School of Life Sciences College of AgricultureEngineering and ScienceUniversity of KwaZulu-Natal(Pietermaritzburg Campus)Private Bag X01Scottsville 3209Republic of South Africa State Key Laboratory of pollution Control and Resource Reuse School of the EnvironmentNanjing UniversityNanjing 210023China Institute of Germplasm Resources and Biotechnology Jiangsu Academy of Agricultural SciencesNanjing 210014China Jiangsu Key Laboratory of Chemical pollution Control and Resources Reuse School of Environmental and Biological EngineeringNanjing University of Science and TechnologyNanjing 210094China

The development of biochar-based granule-like adsorbents suitable for scaled-up application has been attracting increasing attention in the field of water ***,a new formable porous granulated biochar loaded with La-Fe(hydr)oxides/montmorillonite(LaFe/MB)was fabricated via a granulation and pyrolysis process for enhanced phosphorus(p)removal from *** acted as a binder that increased the size of the granulated biochar,while the use of Fe promoted the surface charge and facilitated the dispersion of La,which was responsible for selective phosphate ***/MB exhibited rapid phosphate adsorption kinetics and a high maximum adsorption capacity(Langmuir model,52.12 mg p g^(−1)),which were better than those of many existing granulated *** desorption and recyclability experiments showed that LaFe/MB could be regenerated,and maintained 76.7%of its initial phosphate adsorption capacity after four adsorption *** high hydraulic endurance strength retention rate of the developed material(91.6%)suggested high practical applicability in actual ***-static attraction,surface precipitation,and inner-sphere complexation via ligand exchange were found to be involved in selective p removal over a wide pH range of *** thermodynamic parameters were determined,which revealed the feasibility and spontaneity of *** on approximate site energy distribution analyses,high distribution frequency contributed to efficient p *** research results provide a new insight that LaFe/MB shows great application prospects for advanced phosphate removal from wastewater.

关键词： Formable porous biochar Montmorillonite Metal(hydr)oxide Wastewater phosphate removal Adsorption mechanism

The Knowledge about the potential Health Risks of Illegal Bushmeat Activities among Local Communities Adjacent to western Nyerere National park, Tanzania

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Open Journal of Ecology 2023年第1期13卷 22-36页

作者： Yohani R. Foya charles p. Mgeni Reuben M. J. Kadigi Michael H. Kimaro Shombe N. Hassan Department of Wildlife Management Sokoine University of Agriculture (SUA) Morogoro Tanzania College of Economics and Business Studies Sokoine University of Agriculture Morogoro Tanzania GELIFES University of Groningen Groningen Netherlands Tanzania Research and Conservation Organization Morogoro Tanzania

Establishing knowledge of local communities regarding the potential health risks of illegal bushmeat hunting and its related practices is among the essential means to developing effective conservation and public health programs. To reveal the understanding of the local people regarding the potential health risks of bushmeat consumption and handling of wildlife products, we used a semi-structured questionnaire to survey 261 households in eight villages located adjacent to the western part of Nyerere National park. Also, we interviewed eight key informants, including conservation personnel and veterinary officers, in the study area. The proportion of local people who were unaware that handling of wildlife products and bushmeat consumption were risky behaviours towards acquiring zoonotic diseases was slightly higher (57%) than the proportion of respondents who were aware of the likely risks of zoonotic diseases from the practices. After all, the majority (83%) of local people admitted having come into contact with wildlife products, while over 70% reported having consumed bushmeat. We found that local communities living closer to the park boundaries (products, and that community members who have lived in the area for more than ten years have experienced more contact with wildlife products than immigrants. Moreover, the age of inhabitants and length of stay were found to be the most significant factors in determining the likelihood of bushmeat consumption. Most people seemed to prefer bushmeat to domestic meat, arguing that bushmeat is far more flavorful, tender, not tainted with chemicals, and has less fat, making it safer. Our study demonstrated that local communities participate in risky practices without contemplating the health consequences that could emerge should a zoonotic disease outbreak occur. Among other strategies, we recommended conservation and public health institutions to increase awareness campaig

关键词： Local Communities Bushmeat Consumption Wildlife products Zoonotic Diseases Awareness

Spatial analysis of synergies and trade-offs between the Sustainable Development Goals (SDGs) in Africa

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Geography and Sustainability 2022年第3期3卷 220-231页

作者： Adams Osman Emmanuel Abeashi Mensah Collins Adjei Mensah Yaw Asamoah Suleman Dauda Kofi Adu-Boahen charles Atanga Adongo Department of Geography Education Faculty of Social Sciences EducationUniversity of EducationWinnebaP.O.Box 25WinnebaGhana Department of Geography and Regional planning Faculty of Social SciencesUniversity of Cape CoastPrivate Mail BagCape CoastGhana Department of Tourism and Hospitality Management Faculty of Social SciencesUniversity of Cape CoastPrivate Mail BagCape CoastGhana Schools of Tourism and Hospitality University of JohannesburgP.O.Box 524Auckland Park 2006South Africa Emperiks Research Limited Cape Coast Stadium AvenueCape CoastGhana

Challenges faced by African countries in achieving the goals of sustainable development are similar and trans-boundary. previous analysis of Africa’s progress on the Sustainable Development Goals (SDGs) has largely beennon-spatial, reducing the ability to find spatial relationships between countries and SDGs to help cooperationand proffer country-specific interventions. This study adopted techniques of exploratory and inferential spatialstatistics to assess the successes of African countries from 2016 to 2020 in achieving the goals of sustainable de-velopment. Also, the study sought to understand how the spatial synergies and trade-offs between SDGs vary percountry and time. The results revealed that spatial hotspots of countries with high SDGs scores were mostly con-fined to northern African countries with significant coldspots within central and eastern Africa and few patchesin western and southern Africa for 2016. In 2020, the number of countries forming hotspots reduced, with Cen-tral African countries as significant cold spots. Five main spatial relationships: positive linear, negative linear,concave, convex and undefined complex, were found among countries and the SDGs. However, these spatialrelationships were fluid as they changed over time and with different levels of influence from 2016 to *** study concludes that generic solutions and policies by development agencies, governments, developmentfinance instiutions and other impact investors will not be enough in achieving the SDGs because of the spatialheterogeneity of the continent. Tailored and country-specific policies based on results of spatial statistics matter.

关键词： Africa Development Sustainable development Spatial analysis Hotspots Random forest

Observation of supersymmetric pseudo-Landau levels in strained microwave graphene

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Light(Science & Applications) 2020年第1期9卷 611-617页

作者： Matthieu Bellec charles poli Ulrich Kuhl Fabrice Mortessagne Henning Schomerus Institut de physique de Nice(INpHYNI) Universite Cote d’AzurCNRS06108 NiceFrance Department of physics Lancaster UniversityLancaster LA14YBUK

Using an array of coupled microwave resonators arranged in a deformed honeycomb lattice,we experimentally observe the formation of pseudo-Landau levels in the whole crossover from vanishing to large pseudomagnetic field *** result is achieved by utilising an adaptable setup in a geometry that is compatible with the pseudo-Landau levels at all field *** adopted approach enables us to observe the fully formed flat-band pseudo-Landau levels spectrally as sharp peaks in the photonic density of states and image the associated wavefunctions spatially,where we provide clear evidence for a characteristic nodal structure reflecting the previously elusive supersymmetry in the underlying low-energy *** particular,we resolve the full sublattice polarisation of the anomalous 0th pseudo-Landau level,which reveals a deep connection to zigzag edge states in the unstrained case.

关键词： microwave strained Landau

Schistosomiasis control and the health system in p.R. China

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Infectious Diseases of poverty 2012年第1期1卷 76-83页

作者： charles Collins Jing Xu Shenglan Tang Liverpool School of Tropical Medicine University of LiverpoolLiverpoolUK National Institute of parasitic Diseases Chinese Centre for Disease Control and PreventionShanghaiP.R.China Duke Global Health Institute Duke UniversityDurhamNC 27708USA

Over the last sixty years advances have been made in the control of schistosomiasis in *** are,however,difficult challenges still to be *** paper looks at the extent to which the health system offers a positive environment for the control of the *** starts by tracing three phases in schistosomiasis control:disease elimination strategy through snail control(1950s-early 1980s);morbidity control strategy based on chemotherapy(mid 1980s to 2003);integrated control strategy(2004+).Each one of these phases took place in distinct policy-making *** paper partly draws on these phases to set out five issues of disease control and discusses them in the context of the health system and its recent *** cover the policy-making process,intersectoral action for health,equity and access to health services,funding for public goods and externalities,and strengthening resource management and *** issues form the basis of an agenda for integrating research and capacity strengthening in the Chinese health system with a view to creating a more positive enabling environment for schistosomiasis *** so doing it is important to emphasize the role and integrity of the public sector against its commercialization,the underlying value of equity,a systems wide perspective,and the role of advocacy.

关键词： Schistosomiasis control Health system p.R.China

ENHANCED FLUORESCENCE IMAGING WITH DMSO-MEDIATED OpTICAL CLEARING

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Journal of Innovative Optical Health Sciences 2010年第3期3卷 153-158页

作者： SANJEEV KARMA JAMES HOMAN charles STOIANOVICI BERNARD CHOI Department of Biomedical Engineering University of California IrvineCA 92697USA Department of Developmental and Cell Biology University of California IrvineCA 92697USA Department of Chemistry University of California IrvineCA 92612USA Beckman Laser Institute University of California IrvineCA 92612USA Edwards Lifesciences Center for Advanced Cardiovascular Technology University of California IrvineCA 92697USA

Recent studies have demonstrated that topical application of glycerol on intact skin does not affect its optical scattering *** from our research group recently revisited the use of dimethyl sulfoxide(DMSO)as an agent with optical clearing *** address the use of optical clearing to enhance quantitation of subsurface fluorescence *** employed both in vitro and in vivo model systems to study the effect of topical DMSO application on fluorescence *** in vitro experiments performed on a tissue-simulating phantom suggest that DMSO-mediated optical clearing enables enhanced characterization of subsurface *** topical DMSO application,a marked increase in fluorescence emission was *** 30 min,the fluorescence signal at the DMSO-treated site was 9×greater than the contralateral saline-treated *** ratio increased to 13×at 105 min after agent *** summary,DMSO is an effective optical clearing agent for improved fluorescence emission quantitation and warrants further study in preclinical in vivo *** on outcomes from previous clinical studies on the toxicity profile of DMSO,we postulate that clinical application of DMSO as an optical clearing agent,can be performed safely,although further study is warranted.

关键词： Glycerol spectroscopy fluorescein toxicity