Graphene-like optical light field and its interaction with two-level atoms

The theoretical basis leading to the creation of a light field with a hexagonal honeycomb structure resembling graphene is considered along with its experimental realization and its interaction with atoms. It is argued that associated with such a light field is an optical dipole potential which leads to the diffraction of the atoms, but the details depend on whether the transverse spread of the atomic wave packet is larger than the transverse dimensions of the optical lattice (resonant Kapitza-Dirac effect) or smaller (optical Stern-Gerlach effect). Another effect in this context involves the creation of gauge fields due to the Berry phase acquired by the atom moving in the light field. The experimental realization of the light field with a honeycomb hexagonal structure is described using holographic methods and we proceed to explore the atom diffraction in the Kapitza-Dirac regime as well as the optical Stern-Gerlach regime, leading to momentum distributions with characteristic but different hexagonal structures. The artificial gauge fields too are shown to have the same hexagonal spatial structure and their magnitude can be significantly large. The effects are discussed with reference to typical parameters for the atoms and the fields

Effect of Three Medicinal Plants Extracts on the Growth of Some Yeasts

This study conducted to detect the effect of the ethanolic extracts for some medicinal plants on 16 yeast species isolated from the oral cavity of cancer patients, three plants which are  Lavandula angustifolia, Salvia officinalis and Syzygium aromaticum were used to study their inhibition  bioactivity and compare their effect with three antifungal drugs (Fluconazole, Ketoconazole and Nystatin), the results showed that Ethanolic extract of L. angustifolia exhibited antifungal bioactivity against all yeast species and revealed inhibition zones ranged from 16-36 mm. with highest effect on C. parapsilosis whereas the lowest effect was on species H. uvarum, while the ethanolic extract of S. officinalis and S. aromaticum showed inhibition zones 16-27 mm. and 17-31 mm. respectively, the results showed that the plants extracts having much more effect on the yeasts growth from the antifungal drugs. Keywords: yeasts, medicinal plants, Ethanolic extracts

Isolation and Identification of Candida Species from the Oral Cavity of Cancer Patients Undergoing Chemotherapy in Basrah, Iraq

Candida species are a common normal flora in the human oral cavity , they can cause oral candidiasis especially in the immunocompromised  patients like cancer patients. A total of 500 cancer patients and 200 healthy controls were included in this study. Breast cancer was the most prevalence between patients (145 cases) , followed  by leukemia (114 cases) . Candida albicans was  the most yeast species isolated  from the oral cavity  of the patients  and control persons ,  followed by  C. tropicalis and C. glabrata along with other  non-Candida albicans Candida (NCAC).All the yeast isolates were identified by different phenotypic methods including germ tube and chlamydospores production, growing on chromogenic media and  assimilation  test. Keywords: Yeast, oral cavity, cancer patients, Candida specie

Development of an Advanced Force Field for Water using Variational Energy Decomposition Analysis

Given the piecewise approach to modeling intermolecular interactions for force fields, they can be difficult to parameterize since they are fit to data like total energies that only indirectly connect to their separable functional forms. Furthermore, by neglecting certain types of molecular interactions such as charge penetration and charge transfer, most classical force fields must rely on, but do not always demonstrate, how cancellation of errors occurs among the remaining molecular interactions accounted for such as exchange repulsion, electrostatics, and polarization. In this work we present the first generation of the (many-body) MB-UCB force field that explicitly accounts for the decomposed molecular interactions commensurate with a variational energy decomposition analysis, including charge transfer, with force field design choices that reduce the computational expense of the MB-UCB potential while remaining accurate. We optimize parameters using only single water molecule and water cluster data up through pentamers, with no fitting to condensed phase data, and we demonstrate that high accuracy is maintained when the force field is subsequently validated against conformational energies of larger water cluster data sets, radial distribution functions of the liquid phase, and the temperature dependence of thermodynamic and transport water properties. We conclude that MB-UCB is comparable in performance to MB-Pol, but is less expensive and more transferable by eliminating the need to represent short-ranged interactions through large parameter fits to high order polynomials

Application of Urban Sustainable Design Strategies for Development and Rehabilitation of Al-Qahad Heritage Village

This paper investigates and analyses the redesigning of a heritage village in the southern region of Saudi Arabia to determine the impact of sustainable design strategies and green open spaces for the village rehabilitation. Heritage village development is an important step to consider for sustainable urban planning and design due to its influence in urban development, the local economy, and historical conservation. Al-Qahad heritage village has been selected as the case study due to its involvement with different historical domestic buildings, military castles, and mosques and its location on the main highway between Albaha and other regions. Furthermore, this heritage village reflects in its urban identity the local environment, social culture, and local construction materials and vernacular architecture. The applied approach involved visiting Al-Qahad heritage village for (a) analysis of the site and environmental conditions, (b) mobility survey analysis, and (c) the application of urban sustainable design strategies for redesigning Al-Qahad heritage village. The site visit included a physical survey to determine the current condition of buildings regarding heights, conditions, land use, and construction materials used. The output of the study is to redesign the heritage village including suggesting some other urban facilities, such as a museum, hotel, and other social activities to attract visitors and rehabilitate the village. The study highlights the importance of many urban sustainable design strategies that can be applied in other heritage villages in Saudi Arabia to protect and conserve the historical buildings and invest in these facilities for tourism purposes. Saudi Arabia is a nation rich with heritage villages, which are found across the country especially in the southern region. The study concludes by offering several recommendations for developers and investors

Performance of multi junction photovoltaic cells with high concentration ratio

AbstractConcentrating solar radiation on Photovoltaic (PV) has the potential to replace the expensive PV material with cheaper optical elements which also enhance the overall electrical output. The use of high solar concentration ratios with the triple junction III-V solar cells offers potential of high solar cell efficiency and power output. However, using high concentration ratios will increase the solar cell surface temperature which is inversely proportional to the PV electrical efficiency. This work investigates the effect of active cooling on the performance of triple junction PV cells with high solar concentration (up to 500X) in the harsh environment of Saudi Arabia where ambient temperatures can reach to 50o C in summer time, but with good clearance index of 0.6 and high yearly solar radiation of up to 2200 kWh/m2. Simulation results showed that as the concentration ratio increases, the effect of cooling on the PV efficiency increases

Arrays of dark optical traps on a toroidal surface

We have theoretically constructed light fields that can generate optical potentials representing rectangular arrays of dark optical traps on the surface of a torus. The arrays are not diffraction-limited, and their period can in principle be deeply sub-wavelength. We discuss the challenges anticipated in realising such potentials which will be of great interest for quantum simulations

Establishing domestic low energy consumption reference levels for Saudi Arabia and the wider Middle Eastern region

Saudi Arabia is renowned for its full reliance on fossil fuel energy and lack of an energy regulatory framework for its built environment. The paper focuses on the domestic sector and aims to: (a) establish levels of energy reduction, informed by leading standards (such as Passivhaus in Germany), that can be achieved taking into account the complex local socio-cultural context and environmental factors, and (b) propose a low energy reference definition with a view of encouraging energy retrofitting programs and enforcing domestic low carbon interventions. An energy simulation environment is employed to simulate and analyze energy consumption patterns of three proposed low carbon prototype houses that reflect current house typology and space layout in the country. The three proposed homes offer a reduction in energy consumption of up to 71.6%, compared with similar houses. Based on these findings, a domestic energy performance reference is proposed with energy consumption ranging between 77 kWh/m2 and 98 kWh/m2. Economic and environmental benefits are discussed as well as recommendations for enforcing low carbon design in the country and across the regio

A bioinformatics toolkit: in silico tools and online resources for investigating genetic variation

With the advent of large-scale next-generation sequencing initiatives, there is an increasing importance to interpret and understand the potential phenotypic influence of identified genetic variation and its significance in the human genome. Bioinformatics analyses can provide useful information to assist with variant interpretation. This review provides an overview of tools/resources currently available, and how they can help predict the impact of genetic variation at the deoxyribonucleic acid, ribonucleic acid, and protein level