Effects of Cadmium, Lead, Manganese, and Zinc at WHO Safe Limits in Drinking Water on the in Vitro Availability of Chloramphenicol

In the present study, The in vitro availability of chloramphenicol was studied in the presence of lead (Pb), cadmium (Cd), manganese (Mn) and zinc (Zn) at 0.01, 0.003, 0.5 and 3 mg/L respectively corresponding to WHO safe limits in drinking water for each of the metals. The in vitro availability study was carried out in simulated gastric juice (0.1 M HCl) and intestinal pH (phosphate buffer pH 9.0) at 37°C using a dissolution apparatus. Samples were taken at 15 minutes intervals over a period of 3 hours and analyzed for concentration of chloramphenicol available using a Helios Zeta Model 164617 UV/VIS spectrophotometer at 278nm. In simulated gastric juice, a maximum availability of 99.48 % was achieved for chloramphenicol alone, while 89.48, 93.48, 105.88 and 93.60% of the drug was detected in the presence of Cd, Mn, Pb, and Zn respectively. The corresponding maximum availabilities in simulated intestinal pH were 64.12 for chloramphenicol alone, and 64.36, 83.76, 80.72 and 64.96 % in the presence of Cd, Mn, Pb, and Zn respectively. The presence of Cd did not affect the overall availability of chloramphenicol in both media; while the availability of the drug was observed to increase slightly in the  presence of Pb in both media. In simulated gastric juice, Mn and Zn did not affect the availability of chloramphenicol. However, their presence slightly increased the availability of the drug in simulated intestinal pH. The results of this study indicate that the absorption and subsequent bioavailability of chloramphenicol may not be reduced by Cd, Pb, Mn, and Zn at  concentrations corresponding to WHO safe limits in drinking water. Bioavailability may even be enhanced especially in the intestine, which may result in therapeutic effectiveness. Key words: Chloramphenicol, metal cations, in vitro availabilit

Gender Inequalities and Language Expression in Education

The aim of this research is to investigate whether the difficulties found by men and women in using a language are just caused by their sexual differences. It has been shown that the factor of language expression is more important and determines how men and women should speak. There are a number of factors that influence the differences in language expression, i.e. domination or power, the different ways of treating men and women, and socialization. Because of these factors, we find some expressions in the English language that represent gender inequalities, e.g. asymmetric marked and unmarked terms, and semantic derogation.     Keywords: education, gender, language expressio

Semantic enhanced Markov model for sequential E-commerce product recommendation

To model sequential relationships between items, Markov Models build a transition probability matrix P of size n× n, where n represents number of states (items) and each matrix entry p(i,j) represents transition probabilities from state i to state j. Existing systems such as factorized personalized Markov chains (FPMC) and fossil either combine sequential information with user preference information or add the high-order Markov chains concept. However, they suffer from (i) model complexity: an increase in Markov Model’s order (number of states) and separation of sequential pattern and user preference matrices, (ii) sparse transition probability matrix: few product purchases from thousands of available products, (iii) ambiguous prediction: multiple states (items) having same transition probability from current state and (iv) lack of semantic knowledge: transition to next state (item) depends on probabilities of items’ purchase frequency. To alleviate sparsity and ambiguous prediction problems, this paper proposes semantic-enabled Markov model recommendation (SEMMRec) system which inputs customers’ purchase history and products’ metadata (e.g., title, description and brand) and extract products’ sequential and semantic knowledge according to their (i) usage (e.g., products co-purchased or co-reviewed) and (ii) textual features by finding similarity between products based on their characteristics using distributional hypothesis methods (Doc2vec and TF-IDF) which consider the context of items’ usage. Next, this extracted knowledge is integrated into the transition probability matrix P to generate personalized sequential and semantically rich next item recommendations. Experimental results on various E-commerce data sets exhibit an improved performance by the proposed model

A Survey and Taxonomy of Sequential Recommender Systems for E-commerce Product Recommendation

E-commerce recommendation systems facilitate customers’ purchase decision by recommending products or services of interest (e.g., Amazon). Designing a recommender system tailored toward an individual customer’s need is crucial for retailers to increase revenue and retain customers’ loyalty. As users’ interests and preferences change with time, the time stamp of a user interaction (click, view or purchase event) is an important characteristic to learn sequential patterns from these user interactions and, hence, understand users’ long- and short-term preferences to predict the next item(s) for recommendation. This paper presents a taxonomy of sequential recommendation systems (SRecSys) with a focus on e-commerce product recommendation as an application and classifies SRecSys under three main categories as: (i) traditional approaches (sequence similarity, frequent pattern mining and sequential pattern mining), (ii) factorization and latent representation (matrix factorization and Markov models) and (iii) neural network-based approaches (deep neural networks, advanced models). This classification contributes towards enhancing the understanding of existing SRecSys in the literature with the application domain of e-commerce product recommendation and provides current status of the solutions available alongwith future research directions. Furthermore, a classification of surveyed systems according to eight important key features supported by the techniques along with their limitations is also presented. A comparative performance analysis of the presented SRecSys based on experiments performed on e-commerce data sets (Amazon and Online Retail) showed that integrating sequential purchase patterns into the recommendation process and modeling users’ sequential behavior improves the quality of recommendations

Environmental pollution: a case study of waste water parameters from Ibrahim Adamu Lake, Jigawa, Nigeria

The effects of environmental pollution in relation to waste water parameters from Ibrahim Adamu Lake were examined for a period of 12 Months from October, 2003 - September, 2004. The physico-chemical parameters of pH, Temperature, Dissolved oxygen, Alkalinity, Nitrate, and Phosphate were examined using standard methods (APHA, 1992). It was found that all the evaluated parameters were below the Federal Environmental Planning and Protection Agency (FEPA, 1990) and World Health Organization (WHO,1999) standards

Studi Pendahuluan Keterampilan Pemecahan Masalah dan Metakognisi Siswa SMA Berbasis UAPAC+SE

Metacognition skills such as procedural knowledge, declarative knowledge, conditional knowledge, planning, monitoring, and evaluating are needed to understand problem-solving skills such as controlling and self-evaluation, planning and application, plan analysis, and understanding the problem. This study aims to describe problem-solving skills and student cognition in solving problems in physics subjects of XI IPA students in SMA Negeri 8 Samarinda. The population of the study sample amounted to 116 students grouped based on the results of physics achievement tests as many as 40 questions, divided into three groups, namely: groups of 32 students (28%), middle groups 61 students (53%), and groups under 23 students (20%). The research method used is a descriptive approach to the form of research in the form of case studies. Indicators of problem-solving skills, consisting of understanding the problem, analysis of the problem, planning, application of the plan, controlling & self-evaluation (UAPAC + SE). While metacognition uses the indicator of the Metacognitive Awareness Inventory (MAI). Based on data analysis, it can be concluded that the average problem-solving skills of upper group students (68%) are the high category, middle group students (34%), and lower group students (33%) are low categories. While the average metacognition skills are upper group students (66%) in the high category, middle group students (36%), and lower group students (33%) in the low category

Study on low-grade galena-barite ore beneficiation in Khuzdar, Balochistan, Pakistan

Purpose. Galena and barite are the principal minerals of lead and barium respectively. Both minerals are used extensively in industries because of their distinct properties. In complex poly metallic ores, it is always desirable to produce separate mineral concentrates for subsequent metal extraction. Separation of two or more minerals from complex low-grade multi-metallic ore into commercial grade concentrates requires suitable process. Methods. This research work is centered on development a suitable process for the beneficiation of a low-grade galena-barite ore originating from Khuzdar region (Balochistan Province, Pakistan). Findings. The low-grade ore assaying 39.90% Pb and 24.64% BaSO4 was beneficiated on bench-scale by sequential froth flotation process to recover valuable galena and barite concentrates. The important variables of froth flotation process such as feed size, pulp pH, pulp density, impeller speed, type and quantities of flotation reagents, pulp conditioning time and froth collecting time were optimized to achieve maximum recovery and grade of both concentrates. The rougher galena and barite concentrates were re-ground separately and subjected to one cleaning flotation to obtain better grade final concentrates of respective minerals. Originality. A process flow-sheet was designed in the light of this study. Practical implications. Froth flotation experiments showed that a galena concentrate containing 77.38% Pb with recovery of 90.64% and a barite concentrate assaying 90.23% BaSO4 with recovery of 80.16% could be recovered from this ore. Both the concentrates fall in the category of metallurgical and chemical grades and are suitable for industrial applications.Мета. Підвищення якості низькосортної галеніт-баритової руди, знайденої в Хуздарском районі провінції Белуджистан (Пакистан), до концентрату металургійного якості, що містить більше 70% Pb, із використанням методу пінної флотації. Методика. Масова проба галеніт-баритової руди вагою близько 100 кг була відібрана з шахти Мал-Хор на північному заході від Хуздару та доставлена в лабораторію переробки мінералів MPRC, PCSIR Lahore для проведення досліджень. Зразок підданий первинному подрібненню із використанням щокової дробарки з наступним вторинним подрібненням із використанням валкової дробарки. Зразок до і після флотації піддавався комплексному хімічному і рентгеноструктурному аналізу (XRD). Флотаційні випробування проводилися на лабораторній флотаційній машині D-12. Після визначення оптимального помелу були проведені випробування для оптимізації щільності пульпи, рН пульпи, швидкості перемішування, кількості доданих реагентів, часу флотації й часу кондиціонування. Результати. Встановлено, що вміст свинцю та барію в поліметалічній руді є достатнім для промислового використання. Отримано оптимальну ступінь подрібнення і відновлення при розмірі подачі 80% мінус 200 меш. Виявлено, що збільшення щільності пульпи дещо знижується при збільшенні В/Т з 20 до 35%, але відновлення збільшується, а максимальне відновлення досягнуто при 30%. При використанні для коригування рН пульпи етілксантата калію, а потім бариту з олеатом натрію, виявлено, що при постійних умовах розміру часток і співвідношення твердої речовини та рідини максимально повторне покриття галену досягається при рН 8.5 і бариту при рН 10.0. Було відзначено, що невелика зміна pH значно змінила ступінь і відновлення. Розкрито вплив швидкості перемішування робочого колеса й відзначено, що оптимальною швидкістю на грубій стадії є швидкість 1100 об/хв, а на стадії очищення – 1000 об/хв. Доведено, що методом пінної флотації з даної руди можна отримати концентрат галеніту із вмістом 77.38% Pb і ступенем відновлення 90.64%, а також концентрат бариту із вмістом 90.23% BaSO4 і ступенем відновлення 80.16%. Наукова новизна. Встановлено характер впливу специфічних речовин, що поліпшують показники про-процесу флотації, які сприяють якісному відділенню цінних компонентів руди від порожніх домішок. Практична значимість. Розроблено принципову схему процесу збагачення галеніт-баритової руди на основі пінної флотації в замкнутому циклі. Отримані концентрати галеніту й бариту відповідають необхідним металургійним і хімічним стандартам та можуть знайти промислове застосування.Цель. Повышение качества низкосортной галенит-баритовой руды, найденной в Хуздарском районе провинции Белуджистан (Пакистан), до концентрата металлургического качества, содержащего более 70% Pb, с использованием метода пенной флотации. Методика. Массовая проба галенит-баритовой руды весом около 100 кг была отобрана из шахты Мал-Хор к северо-западу от Хуздара и доставлена в лабораторию переработки минералов MPRC, PCSIR Lahore для проведения исследований. Образец подвергнут первичному дроблению с использованием щековой дробилки, с последующим вторичным дроблением с использованием валковой дробилки. Образец до и после флотации подвергался комплексному химическому и рентгеноструктурному анализу (XRD). Флотационные испытания проводились на лабораторной флотационной машине D-12. После определения оптимального помола были проведены испытания для оптимизации плотности пульпы, рН пульпы, скорости перемешивания, количества добавленных реагентов, времени флотации и времени кондиционирования. Результаты. Установлено, что содержание свинца и бария в полиметаллической руде является достаточным для промышленного использования. Получена оптимальная степень измельчения и восстановления при размере подачи 80% минус 200 меш. Выявлено, что увеличение плотности пульпы несколько снижается при увеличении В/Т с 20 до 35%, но восстановление увеличилось, а максимальное восстановление достигнуто при 30%. При использовании для корректировки рН пульпы этилксантата калия, а затем барита с олеатом натрия, обнаружено, что при постоянных условиях размера частиц и соотношения твердого вещества и жидкости максимальное повторное покрытие галена достигается при рН 8.5 и барита при рН 10.0. Было отмечено, что небольшое изменение pH значительно изменило степень и восстановление. Раскрыто влияние скорости перемешивания рабочего колеса и отмечено, что оптимальной скоростью на грубой стадии является скорость 1100 об/мин, а на стадии очистки – 1000 об/мин. Доказано, что методом пенной флотации из данной руды можно получить концентрат галенита с содержанием 77.38% Pb и степенью восстановления 90.64%, а также концентрат барита с содержанием 90.23% BaSO4 и степенью восстановления 80.16%. Научная новизна. Установлен характер влияния специфических веществ, улучшающих показатели процесса флотации, что способствовало качественному отделению ценных компонентов руды от пустых примесей. Практическая значимость. Разработана принципиальная схема процесса обогащения галенит-баритовой руды на основе пенной флотации в замкнутом цикле. Полученные концентраты галенита и барита соответствуют металлургическим и химическим стандартам и могут найти промышленное применение.The authors are grateful to Associate Professor, Dr. Zulifqar Ali, Department of Mining Engineering, University of Engineering and Technology (UET), Lahore for his valuable support/ cooperation in X-ray diffraction (XRD) analysis and mineralogical evaluation of ore

Toward Mobile-Assisted Language Learning (MALL): Reaping Mobile Phone Benefits in Classroom Activities

Mobile phone has been studied by researchers in its connection with education-related activies. This study was aimed at investigating two research questions: 1) what are students' perception toward mobile phone to support classroom activities; 2) How do students experience mobile phone use to support classoom activities? This study employed qualitative method. To collect data, there were some technique used: questionnaire and observation. Students participated in this study were 70 students. Findings showed that student had positive perception and attitude toward mobile phone to support classroom activities. In classroom they used mobile phone to support classroom activitis. Reading E-Book that support subject, playing Audio and Video File, operating offline dictionary were activities supported by mobile phone use