Dual-wave β-correction spectrophotometric determination of palladium ions using neothorin

AbstractA simple low cost method has been developed and validated for the determination of trace amounts of palladium (II) ions in water and fertilizer samples. The method is based on the reaction of palladium (II) ions with the reagent neothorin (2-(2-arsonophenylazo) chromotropic acid disodium salt). The complex formed exhibits an absorption maximum at 567nm (λmax) in Britton–Robinson (BR) buffer (pH=2). The corrected absorbance of the formed complex at λmax was obtained by employing a β-correction spectrophotometric method. The Beer–Lambert law and Ringbom's plots of the coloured palladium reagent complex were obeyed in the concentration ranges of 0.05–2.7 and 0.1–2μgmL−1 palladium (II) ions, respectively, with relative standard deviations in the range of ±1.3–2.1%. The limits of detection (LOD) and quantitation (LOQ) of the procedure were 0.011 and 0.04μgmL−1 palladium, respectively. The proposed method was applied for the analysis of palladium (II) ions in spiked tap, mineral and underground water samples. The results of the developed method were satisfactorily compared with the data obtained by the inductively coupled plasma-mass spectrometric (ICP-MS) method. Statistical comparison of the results of the proposed method with those obtained by the standard method revealed no significant differences in accuracy and precision. The developed method offers a simple system coupled with good reproducibility, accuracy, ruggedness and cost effectiveness

Brain abscess following rituximab infusion in a patient with pemphigus vulgaris.

BackgroundImmunocompromised patients are at increased risk for developing meningitis or, rarely, brain abscess with opportunistic organisms like Listeria monocytogenes.Case reportA 52 year-old Saudi Arabian woman who was diagnosed with pemphigus vulgaris and diabetes and had been on prednisolone and azathioprine for about 4 years. She presented with headache, low-grade fever, and left-sided weakness 2 weeks after receiving the second dose of rituximab infusion. Magnetic resonance imaging revealed an enhanced space-occupying lesion with multiple small cyst-like structures and vasogenic edema in the right temporoparietal area. Her blood culture was positive for Listeria monocytogenes, and a brain biopsy showed necrotic tissues with pus and inflammatory cells. She recovered after a 6-week course of antibiotics with ampicillin and gentamycin.ConclusionsBrain abscess due to Listeria monocytogenes is a risk that should be considered when adding rituximab to the regimen of a patient who is already Immunocompromised

Statistical Analysis of a Linear Multi-Step Numerical Treatment

The aim of this paper is to compare the relative accuracies between predictor-corrector methods, Adams-Bashforth method and Adams-Moulton method for solving initial value Differential Equations numerically to observe which methods tend to function well in which step-size brackets as well as which ones provide the minimum amount of error when compared to the true value. The statistical analysis shows that there is always a small amount of error present using Heun’s method; however, the error is rarely large enough unless the function is rapidly rising

On Estimating a Constant Stress Life Test Model Using Time-Censored Data from the Linear Failure Rate Distribution

In this paper, a constant stress partially accelerated life test model is considered and investigated using type-I censored data from the linear failure rate distribution. The maximum likelihood estimates (point and interval) of the distribution parameters and the acceleration factor are obtained. For accuracy reasons, the mean squared errors are calculated using different sizes of samples. For illustration, Monte Carlo simulation studies are presented.Предложена модель частично ускоренных испытаний на циклическую долговечность с постоянным напряжением с использованием данных, подвергнутых цензурированию типа I с линейным распределением скорости разрушения. Получены точечные и интервальные оценки максимального правдоподобия параметров распределения и коэффициента ускорения. С целью повышения точности прогнозов расчет среднеквадратических погрешностей осуществлялся для образцов разных размеров. Для иллюстрации работоспособности модели выполнено моделирование тестовых задач с использованием метода Монте-Карло.Запропоновано модель частково прискорених випробувань на циклічну довговічність з постійною напругою з використанням даних, які було піддано цензуруванню типу I із лінійним розподілом швидкості руйнування. Отримано точкові й інтервальні оцінки максимальної правдоподібності параметрів розподілу і коефіцієнта прискорення. Із метою підвищення точності прогнозів розрахунок середньоквадратичних похибок проводився для зразків різних розмірів. Для ілюстрації роботоздатності моделі виконано моделювання тестових задач із використанням методу Монте-Карло

Human-Induced Geo-Hazards in the Kingdom of Saudi Arabia: Distribution, Investigation, Causes and Impacts

Different types of geological hazards are induced by human activities in the Kingdom of Saudi Arabia (KSA). These geological hazards include land subsidence and earth fissures, sinkholes, expansive soils, and flash floods. A wide variety of recent geological hazards have been reported in several areas, causing significant human and property losses. Human activities, most notably groundwater extraction, infrastructure development, and agricultural activities, have induced unstable conditions. This chapter provides an overview of the human-induced geological hazard in the KSA, mainly earth fissures and sinkhole, which represent a scarcely explored topic. This work identifies the main types of human-induced geological-hazard formations, distribution, causes, and impacts, illustrated through several case studies in the KSA

Different chemical behaviors and antioxidant activity of three novel schiff bases containing hydroxyl groups. X-ray structure of CH2{cyclo-C6H10-NH=CH-(2-O-naphth)}2.H2O

The antioxidant activities of three new Schiff base compounds, 1–3, were studied through their direct scavenging ability to eliminate free radicals using DPPH and ABTS methods and also through their indirect antioxidant activity as measured using the ferric thiocyanate (FTC) method. The number of OH groups in the compounds and their positions play a role in the activity. The crystal structure of CH2{cycloC6H10NHCH-(2-O-naphth)}2.H2O (1), has been determined and proves the existence of intramolecular hydrogen-bonds and hydrogen-bonded water molecules and reveals the keto-amine (NH⋯O) tautomer of this compound. One cyclo-hexyl ring was found to be disordered, and was resolved in two orientations. Hydrogen atoms of the NHCH groups were located in difference maps and were refined freely. Compounds 2 and 3 exhibit the enol-imine form. The UV–vis spectra of the three compounds have been studied in organic solvents of different polarity, and in basic and acidic media, and were found helpful in understanding the tautomeric forms in these compounds; the polarity was modified by adding (CF3COOH) or [(C2H5)3N] to the solvent. All three compounds have been characterized by elemental analysis, UV–vis, FTIR, NMR and MS

PURIFICATION AND CHARACTERIZATION OF HIGHLY STABLE ALDO-KETO REDUCTASE FROM CAMEL (CaMelus DRoMeDaRius) LIVER

Abstract -Aldo-keto reductase (AKR) was purified to homogeneity from camel liver by ion exchange on Q Sepharose, affinity chromatography on Blue-Sepharose and 2,5-ADP-Sepharose 4B. The purification procedure resulted in 32.43-fold purification with 0.65% final yield. Subunit and native molecular weights of the purified enzyme determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration chromatography, were 33kD and 133kD, respectively. The purified AKR exhibited maximal activity at a temperature of 50°C and pH of 7.0. The K m values for NADPH and NADH calculated from the Lineweaver-Burk plot were 0.01 mM and 0.083 mM, respectively, whereas the Km values for m-Nitrobenzaldehyde, 4-Anisaldehyde and P-Benzoquinone were 0.9 mM, 1.11 mM and 0.57 mM, respectively

Evaluation of Saudi International Educational Programs using Rossi and His Colleagues Evaluation Model

This study aimed to evaluate international educational programs (IEP) of the Saudi private schools, their need, design, inputs, processes, outputs and impact using the hierarchical evaluation model (HEM) of Rossi and his colleagues. The methodology adopts dual quantitative and qualitative methods. The evaluation includes Saudi private schools applying such programs, and samples of some foreign schools and foreign community schools employing deep comparisons, questionnaires, field observations and interviews of administrators, teachers, students and parents. This evaluation shows that HEM helped in grading evaluation and determining questions that suit program grade. Results show that IEP maintain students’ identity, and achieve outcomes reasonably. They reduced student enrollment in foreign programs, and helped raise their knowledge, language, personal and educational skills to a global level. However, there is lack of clear program theory that identifies inputs, processes and outcomes, lack of clarity in program mechanisms, design, needs assessment, performance monitoring and evaluation. They show limited external evaluation, with no standardized or uniform standards for teachers selection and intake as well as final achievement exams. They likewise show lack of information for parents and community members. This study recommends the expansion of experience provided that international standards of programs quality and monitoring be ensured

The Ameliorative Effect of Green Tea, Garlic and Vitamin C on Arsenic Toxicity in Male Mice: Biochemical and Histological Forensic Perspectives

Arsenic is a heavy metal with toxic effects on human health and is widely found in the environment. It is used in suicides and, hence, acquires forensic impact. Sixty adult male albino mice weighing 30-40 g were subjected to a sub-lethal dose of sodium arsenate (40 mg/kg body weight) to investigate hematological, biochemical and histopathological alterations in liver and kidney. The mice were also co-treated with green tea, garlic and vitamin C to reveal the protective role of these herbal and synthetic antioxidants. Arsenic induced significant declines in all blood parameters, while green tea, garlic and vitamin C ameliorated these affected hematological parameters. Alanine transaminase (ALT) and aspartate transaminase (AST) were significantly increased in the sodium arsenate treated group, while green tea, garlic and vitamin C ameliorated these increases in enzyme levels. Creatinine and urea were significantly increased in arsenic treated mice. These renal parameters become normal in mice co-treated with green tea, garlic and vitamin C. Arsenate-treated mice showed venous congestion, sinusoidal dilatation, mononuclear cell infiltration and periportal fibrosis in liver sections. Kidney samples from the same group revealed interstitial hemorrhages, mononuclear cell infiltration, glomerulonephritis and proximal tubular necrosis. Hepato-renal injuries were greatly reduced, particularly in animals that received both green tea and garlic. The herbs used have a potential for ameliorating and protecting against the hepato-renal toxicity caused by arsenic and need further studies. This study revealed the possibility of using liver and kidney as indicators to ascertain arsenic poisoning in forensic casework