The DFT+U: Approaches, Accuracy, and Applications

This chapter introduces the Hubbard model and its applicability as a corrective tool for accurate modeling of the electronic properties of various classes of systems. The attainment of a correct description of electronic structure is critical for predicting further electronic-related properties, including intermolecular interactions and formation energies. The chapter begins with an introduction to the formulation of density functional theory (DFT) functionals, while addressing the origin of bandgap problem with correlated materials. Then, the corrective approaches proposed to solve the DFT bandgap problem are reviewed, while comparing them in terms of accuracy and computational cost. The Hubbard model will then offer a simple approach to correctly describe the behavior of highly correlated materials, known as the Mott insulators. Based on Hubbard model, DFT+U scheme is built, which is computationally convenient for accurate calculations of electronic structures. Later in this chapter, the computational and semiempirical methods of optimizing the value of the Coulomb interaction potential (U) are discussed, while evaluating the conditions under which it can be most predictive. The chapter focuses on highlighting the use of U to correct the description of the physical properties, by reviewing the results of case studies presented in literature for various classes of materials

DETERMINATION OF COPPER, ZINC, CADMIUM AND LEAD IN WATER USING DIFFUSE REFLECTANCE SPECTROSCOPY METHOD

Found the concentration conditions of copper, zinc, cadmium and lead from aqueous solutions using clay mineral modified with rhodamine B. It is established that colorimetric characteristics of colored complexes Cu2+ , Zn2+, Cd2+, and Pb2+ with rhodamine B, immobilized on montmorillonite containing clay, depend on the pH and heavy metalsconcentration in the aqueous phase. The distribution coefficients of metals were obtained. Determined the maximum allowable concentrations of macro components of water that do not hinder the formation of complexes of heavy metals with rhodamine B immobilized on clay. To eliminate the interfering effect of metals at their joint presence in aqueous solutions the appropriate masking agents were proposed. On the basis of the obtained dependences the highly sensitive technique for determination of copper, zinc, cadmium and lead in drinking water by diffuse reflectance spectroscopy was developed. Estimated metrological characteristics of the proposed methods: the relative standard deviation (sr) analysis of water samples was 0.01-0.08; detection limit and the linearity range of the determination of heavy metals in drinking water was, mcg/l: Cu2+ – 0.6, 1.8-100; Zn2+ – 1.6, 4.8-100; Cd2+ – 0.5, 1.5-100; Pb2+ – 5.0, 15-600, respectively. The method was tested using the real samples of natural water.Keywords: clay mineral, rhodamine B, modification, heavy metals, sorption, method of determination, drinking water(Russian)DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.002 A.Sh. Ramazanov, Esmail Gameel Qasim Daghestan State University, Makhachkala, Republic Daghestan,Russian FederationFound the concentration conditions of copper, zinc, cadmium and lead from aqueous solutions using clay mineral modified with rhodamine B. It is established that colorimetric characteristics of colored complexes Cu2+ , Zn2+, Cd2+, and Pb2+ with rhodamine B, immobilized on montmorillonite containing clay, depend on the pH and heavy metalsconcentration in the aqueous phase. The distribution coefficients of metals were obtained. Determined the maximum allowable concentrations of macro components of water that do not hinder the formation of complexes of heavy metals with rhodamine B immobilized on clay. To eliminate the interfering effect of metals at their joint presence in aqueous solutions the appropriate masking agents were proposed. On the basis of the obtained dependences the highly sensitive technique for determination of copper, zinc, cadmium and lead in drinking water by diffuse reflectance spectroscopy was developed. Estimated metrological characteristics of the proposed methods: the relative standard deviation (sr) analysis of water samples was 0.01-0.08; detection limit and the linearity range of the determination of heavy metals in drinking water was, mcg/l: Cu2+ – 0.6, 1.8-100; Zn2+ – 1.6, 4.8-100; Cd2+ – 0.5, 1.5-100; Pb2+ – 5.0, 15-600, respectively. The method was tested using the real samples of natural water.Keywords: clay mineral, rhodamine B, modification, heavy metals, sorption, method of determination, drinking water.DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.00

Determination of copper, zinc, cadmium and lead in water using diffuse reflectance spectroscopy method

Изучена возможность определения меди, цинка, кадмия и свинца в водах методом спектроскопии диффузного отражения с использованием глинистого минерала, модифицированного родамином Б. Оптимизированы условия концентрирования металлов из водных растворов с использованием модифицированного сорбента. Установлены цветометрические характеристики окрашенных комплексов тяжелых металлов с родамином Б, иммобилизованным на глинистый минерал, условия образования которых зависят от рН и концентраций металлов в водной фазе. Определены коэффициенты распределения металлов. Изучено влияние макрокомпонентов воды на образование комплексов тяжелых металлов с родамином Б, иммобилизованным на глине. Для устранения мешающего влияния определяемых металлов при их совместном присутствии в воде предложены соответствующие маскирующие реагенты. На основе полученных зависимостей разработана методика определения меди, цинка, кадмия и свинца в питьевой воде методом спектроскопии диффузного отражения. Оценены метрологические характеристики предложенной методики: относительные стандартные отклонения ( s r) результатов анализа проб воды составили 0.01-0.08; пределы обнаружения тяжелых металлов в питьевой воде и диапазон линейности соответственно составили, мкг/л: Cu²⁺ - 0.6, 1.8-100; Zn²⁺ - 1.6, 4.8-100; Cd²⁺ - 0.5, 1.5-100; Pb²⁺ - 5.0, 15-600. Методика анализа апробирована на реальных образцах природной воды.Found the concentration conditions of copper, zinc, cadmium and lead from aqueous solutions using clay mineral modified with rhodamine B. It is established that colorimetric characteristics of colored complexes Cu²⁺, Zn²⁺, Cd²⁺, and Pb²⁺ with rhodamine B, immobilized on montmorillonite containing clay, depend on the pH and heavy metalsconcentration in the aqueous phase. The distribution coefficients of metals were obtained. Determined the maximum allowable concentrations of macro components of water that do not hinder the formation of complexes of heavy metals with rhodamine B immobilized on clay. To eliminate the interfering effect of metals at their joint presence in aqueous solutions the appropriate masking agents were proposed. On the basis of the obtained dependences the highly sensitive technique for determination of copper, zinc, cadmium and lead in drinking water by diffuse reflectance spectroscopy was developed. Estimated metrological characteristics of the proposed methods: the relative standard deviation (sr) analysis of water samples was 0.01-0.08; detection limit and the linearity range of the determination of heavy metals in drinking water was, mcg/l: Cu²⁺ - 0.6, 1.8-100; Zn²⁺ - 1.6, 4.8-100; Cd²⁺ - 0.5, 1.5-100; Pb²⁺ - 5.0, 15-600, respectively. The method was tested using the real samples of natural water

Sinteza i antimikrobno djelovanje derivata nafto[2,1-b]pirano[2,3-d]pirimidina i pirano[3,2-e][1,2,4]triazolo[1,5-c]pirimidina

Several novel naphtho[2,1-b]pyrano[2,3-d]pyrimidines, pyrano[3,2-e][1,2,4]triazolo[1,5-c]pyrimidines and their coumarin-3-yl derivatives were synthesized. Some of these derivatives exhibited pronounced antimicrobial activities.Sintetizirano je nekoliko novih nafto[2,1-b]pirano[2,3-d]pirimidina, pirano[3,2-e][1,2,4]triazolo[1,5-c]pirimidina i njihovih kumarin-3-il derivata. Neki od njih imaju izraženo antimikrobno djelovanje

Potential effect of Nigella sativa against Diethylnitrosamine-induced hepatocarcinogenesis in rats

Objective of the investigation was the study of potential protective effects of the watery extract of Nigella sativa against diethylnitrosamine induced hepatocarcinogenesis in rats. N. sativa was administered to rats for protection against diethylnitrosamine-induced hepatocarcinogenesis. It was administered prior to, simultaneously with or after injection of diethylnitrosamine. Five groups of Wister rats were used. Group A was administered diethylnitrosamine and N. sativa simultaneously, group B was administered only diethylnitrosamine and group C received only N. sativa. These three groups were maintained for up to eight weeks. Group D received N. sativa six weeks after administration ofdiethylnitrosamine,while group E (“protective group”) received N. sativa on day 1 and diethylnitrosamine six weeks later. These two groups were maintained for up to 12 weeks. All rats were subjected to partial hepatectomy to enhance carcinogenesis. P-isoform of glutathione s transferase (GST-P) was detected in the cytoplasm and nuclei of hepatocytes. The number of GST-P positive foci was significantly smaller in test groups (A, D, E), particularly in groups A and E, when compared with to those in group B, indicating that N. sativa has protective effects against diethylnitrosamine induced liver cancer in rats, even in the very early stages of hepatocarcinogenesis

Gonadal infection: a risk factor for the development of adolescent varicocele

Objective: The aim of this study was to determine whether a relationship between previous gonadal infections and adolescent varicocele occurrence exists.Patients and methods: All adolescents who presented with varicocele at Tanta Urology Department during the period from January 2006 to March 2011 were included in this study. Patients were evaluated for age, clinical presentation, previous history of epididymitis or epididymoorchitis, laterality, and grading of varicocele. Examination of testicular consistency and ultrasound measurement of testicular volume were carried out for all patients to define those with testicular atrophy.Results: Sixty-three boys were included in this study. The mean patients’ age was 15.6 years (range: 10–18, SD; 1.6 years). Twenty-nine (44.4%) boys had signs of testicular atrophy (testes are soft in consistency with ultrasounddetected volume smaller than that normal for age) either unilateral or bilateral. About 28.6% of patients (18 boys) had a history of epididymitis or epididymo-orchitis either associated with mumps or of unknown etiology. Of those patients, six boys had previous history of single attack, 10 boys had two attacks, and two boys had more than two attacks of epididymo-orchitis. A significant positive correlation was seen between the incidence of epididymo-orchitis attacks and the grade of varicocele (rs=0.63, 95% confidence interval: 0.21–0.85, P<0.05). Patients with past history of epididymo-orchitis were significantly more liable (4.1 times) of developing testicular atrophy as compared with those without a history of epididymo-orchitis (95% confidence interval: 1.517–11.097, P<0.05).Conclusion: History of epididymo-orchitis is significantly a potential risk factor for the development of adolescent varicocele with subsequently higher risk for testicular atrophy. We advise routine ultrasonographic examinations in patients with previous history of epididymo-orchitis both for possible early detection of varicocele and to avoid testicular atrophy in this cohort of patients. However, more studies on a larger scale are still warranted.Keywords: adolescent varicocele, epididymo-orchitis, testicular atroph

Paratuberculosis: The Hidden Killer of Small Ruminants

Paratuberculosis (PTB) is a contagious and chronic enteric disease of ruminants and many non-ruminants caused by Mycobacterium avium subsp. paratuberculosis (MAP), and is characterised by diarrhoea and progressive emaciation with consequent serious economic losses due to death, early culling, and reduced productivity. In addition, indirect economic losses may arise from trade restrictions. Besides being a production limiting disease, PTB is a potential zoonosis; MAP has been isolated from Crohn’s disease patients and was associated with other human diseases, such as rheumatoid arthritis, Hashimoto’s thyroiditis, Type 1 diabetes, and multiple sclerosis. Paratuberculosis in sheep and goats may be globally distributed though information on the prevalence and economic impact in many developing countries seem to be scanty. Goats are more susceptible to infection than sheep and both species are likely to develop the clinical disease. Ingestion of feed and water contaminated with faeces of MAP-positive animals is the common route of infection, which then spreads horizontally and vertically. In African countries, PTB has been described as a “neglected disease”, and in small ruminants, which support the livelihood of people in rural areas and poor communities, the disease was rarely reported. Prevention and control of small ruminants’ PTB is difficult because diagnostic assays demonstrate poor sensitivity early in the disease process, in addition to the difficulties in identifying subclinically infected animals. Further studies are needed to provide more insight on molecular epidemiology, transmission, and impact on other animals or humans, socio-economic aspects, prevention and control of small ruminant PTB

Flexible Wearable Antenna on Electromagnetic Band Gap using PDMS substrate

A robust and low-profile electromagnetic band-gap (EBG) based on flexible wearable antenna covering 2.4 GHz frequency band is presented. The incorporated EBG with antenna reduces the  radiation into the human body around 17 dB and decreases the impacts of frequency detuning. The overall dimension of the antenna integrated with EBG is 56 x 56 x 4 mm3 with relative impedance bandwidth of 8.3% is achieved. The proposed design has improved the gain up to 7 dBi. Specific absorption rate (SAR) assessment is also studied to certify the performance of the antenna when it is located proximity to human tissue. The flexible antenna with aforementioned performances could be chosen as a good candidate for integration into a range of wearable devices for medical application