145 research outputs found
Determination of caffeine in roasted and irradiated coffee beans with gamma rays by high performance liquid chromatography
The present study was carried out to investigate a simple, quick and organic solvent saving procedure for the high performance liquid chromatography determination of caffeine in two different coffee beans (Indonesian and Brazilian) which roasted at two different temperatures (150 & 220 ºC) and irradiated at 3, 6, and 9 kGy doses by gamma rays. A linear calibration curve was generated with caffeine concentration ranging from 0.005 to 0.25 mg/g with correlation coefficient (R2= 0.9995, n=4) and relative standard deviation ? 2.1 %. The developed procedure provided a 7.3 x 10-9 mg/g and 2.2 x 10-8 mg/g limit of detection and limit of quantification, respectively. The developed method was repeatable and could be applied to determine trace amounts of caffeine in popular irradiated coffee beans with three different irradiation doses. Moreover, irradiation treatments at doses up to 9 kGy showed no significant effect on the caffeine content. Keywords: Caffeine determination; High performance liquid chromatography; Coffee bean; Roasting; Gamma rays; Statistical analysi
Bronchoscopic Advances in the Management of Aerodigestive Fistulas
Malignant aerodigestive fistula (ADF) is an uncommon condition complicating thoracic malignancies. It results in increased morbidity and mortality and warrants therapeutic intervention. The management approach depends on symptoms, configuration, location, and extent of the fistula. This article will discuss the therapeutic considerations in the management of ADF
Performance Improvements of a Permanent Magnet Synchronous Machine via Functional Model Predictive Control
This paper investigates the application of the model predictive control (MPC) approach to control the speed of a permanent magnet synchronous motor (PMSM) drive system. The MPC is used to calculate the optimal control actions including system constraints. To alleviate computational effort and to reduce numerical problems, particularly in large prediction horizon, an exponentially weighted functional model predictive control (FMPC) is employed. In order to validate the effectiveness of the proposed FMPC scheme, the performance of the proposed controller is compared with a classical PI controller through simulation studies. Obtained results show that accurate tracking performance of the PMSM has been achieved
Reservoir formation damage; reasons and mitigation : a case study of the Cambrian–Ordovician Nubian ‘C’ sandstone gas and oil reservoir from the Gulf of Suez Rift Basin
Structural, Optical and Single-domain Magnetic Features of the Noncollinear Ferrimagnetic Nano-spinel Chromites ACrO (A = Ni, Co, and Mn)
Spinel chromites ACrO with inherent magnetic geometrical frustration
usually exhibit a noncollinear ferrimagnetic ground state when A are magnetic
ions, with possibly crystallite-size dependent intriguing magnetic features.
Here, we report single-domain magnetic properties of ACrO (A = Ni, Co,
and Mn) nanocrystals, with an average crystallite size of 18, 15 and 10 nm,
exhibiting an optical energy gap of 2.87, 3.05 and 2.9 eV, respectively. The
temperature dependence of magnetization indicates the main bulk magnetic
transitions with a commonly coexisting spin-glass-like state and finite-size
effects on the noncolinear ferrimagnetic transitions. An anomaly observed at Ts
= 15, 24 and 10 K is attributed to the bulk magnetic transition to a canted
antiferromagnetic state in NiCrO and incommensurate spiral orders in
CoCrO and MnCrO NCs, respectively. A further bulk magnetic
transition to a commensurate spiral order is observed for CoCrO NCs at
a lock-in temperature Tl = 5 K much lower than that reported using bulk
samples, while it is completely suppressed in the MnCrO NCs.
Finite-size effects and single-domain magnetic behaviors indicated by anomalous
temperature-dependences of the coercive field and the hysteresis-loop
squareness, mainly driven by a magnetocrystalline anisotropy, are discussed in
comparison to results reported using bulk counterparts
Identifying leaf rust resistance gene Lr19 in durum wheat using simple sequence repeat (SSR) marker
Leaf rust, caused by Puccinia triticina Eriks., is an important disease affecting durum wheat (Triticum turgidum ssp. durum) worldwide, particularly in the Mediterranean region. The disease can be controlled through the use of plant host resistance. Based on seedling resistance tests of 103 durum genotypes against a bulk of P. triticina, urediniospores were previously collected from Syria and Lebanon during 2007/08 and 2008/09 growing seasons. Percentage of resistance in the durum set tested was up to 52%. The resistant genotypes might have one of the following resistance gene(s): Lr15, Lr 19, Lr 24, Lr 25, Lr 27 +31, Lr 28 and Lr 29. Results revealed that the Gb/130-bp polymorphic band was linked to Lr19 and Sr25. In this study, twelve genotypes carrying resistance to Lr19 and Sr25 have been identified (Azeghar2, Rutucha1, Ammar9/Azeghar2, Ammar9/Terbol97-4, T.polonicum9/Ch1//Icamor-TA04-68/3/Icamor-TA04-69//(Lahn/ Ch1)2519, Arislahn5//Icamor-TA04- 63/Icasyr1, T.dicoccum1/Ch1//Ammar8/3/Bonadur/Icamor-TA04-63, Mrb3/ T. urartu500651/4/Icamor- TA04-63/3/Bcr/Gro1// Mgnl1, SwAlg/Gd1-81 //Ch1-48, Icamor-TA04-1//Mgnl3/Ainzen1, 319-ADDO/5/D68-1- 93A-1A//Ruff/Fg/3/Mtl5/4/Lahn, and Mrf1/Stj2/3/1718/BT24//Karim). Promising results on Gb/130-bp and genotypes carrying Lr19 and Sr25 will be used in a marker assisted selection of the durum breeding programs in the Mediterranean region.Key words: Puccinia triticina, durum genotypes, Syria, Lebanon, Lr19, Sr25, Gb primer
Diagenetic overprint on porosity and permeability of a combined conventional-unconventional reservoir : insights from the Eocene pelagic limestones, Gulf of Suez, Egypt
Fabrication and Characterization of Effective Biochar Biosorbent Derived from Agricultural Waste to Remove Cationic Dyes from Wastewater
The main aim of this work is to treat sugarcane bagasse agricultural waste and prepare an efficient, promising, and eco-friendly adsorbent material. Biochar is an example of such a material, and it is an extremely versatile and eco-friendly biosorbent to treat wastewater. Crystal violet (CV)-dye and methylene blue (MB)-dye species are examples of serious organic pollutants. Herein, biochar was prepared firstly from sugarcane bagasse (SCB), and then a biochar biosorbent was synthesized through pyrolysis and surface activation with NaOH. SEM, TEM, FTIR, Raman, surface area, XRD, and EDX were used to characterize the investigated materials. The reuse of such waste materials is considered eco-friendly in nature. After that, the adsorption of MB and CV-species from synthetically prepared wastewater using treated biochar was investigated under various conditions. To demonstrate the study’s effectiveness, it was attempted to achieve optimum effectiveness at an optimum level by working with time, adsorbent dose, dye concentration, NaCl, pH, and temperature. The number of adsorbed dyes reduced as the dye concentrations increased and marginally decreased with NaCl but increased with the adsorbent dosage, pH, and temperature of the solution increased. Furthermore, it climbed for around 15 min before reaching equilibrium, indicating that all pores were almost full. Under the optimum condition, the removal perecentages of both MB and CV-dyes were ≥98%. The obtained equilibrium data was represented by Langmuir and Freundlich isotherm models. Additionally, the thermodynamic parameters were examined at various temperatures. The results illustrated that the Langmuir isotherm was utilized to explain the experimental adsorption processes with maximum adsorption capacities of MB and CV-dyes were 114.42 and 99.50 mgg, respectively. The kinetic data were estimated by pseudo-first and pseudo-second-order equations. The best correlation coefficients of the investigated adsorption processes were described by the pseudo-second-order kinetic model. Finally, the data obtained were compared with some works published during the last four years
Preparation and in vivo Assessment of Nystatin-Loaded Solid Lipid Nanoparticles for Topical Delivery against Cutaneous Candidiasis
Solid lipid nanoparticles (SLNs) have gained great attention for the topical treatment of skin associated fungal infection as they facilitate the skin penetration of loaded drugs. Our work deals with the preparation of nystatin loaded solid lipid nanoparticles (NystSLNs) using the hot homogenization and ultrasonication method. The prepared NystSLNs were characterized in terms of entrapment efficiency, particle size, zeta potential, transmission electron microscopy, differential scanning calorimetry, rheological behavior and in vitro drug release. A stability study for 6 months was performed. A microbiological study was conducted in male rats infected with Candida albicans, by counting the colonies and examining the histopathological changes induced on the skin of infected rats. The results showed that SLNs dispersions are spherical in shape with particle size ranging from 83.26±11.33 to 955.04±1.09 nm. The entrapment efficiencies are ranging from 19.73±1.21 to 72.46±0.66% with zeta potential ranging from -18.9 to -38.8 mV and shear-thinning rheological Behavior. The stability studies done for 6 months showed that nystatin (Nyst) is a good candidate for topical SLN formulations. A least number of colony forming unit/ ml (cfu/ml) was recorded for the selected NystSLN compared to the drug solution and the commercial Nystatin® cream present in the market. It can be fulfilled from this work that SLNs provide a good skin targeting effect and may represent promising carrier for topical delivery of Nyst offering the sustained release and maintaining the localized effect, resulting in an effective treatment of cutaneous fungal infection
Assessing Pharmacists Knowledge and Attitude Toward the Direct Oral Anticoagulants in Qatar
Pharmacists were found to play a key role in anticoagulation care. In order to make an appropriate selection and counselling regarding direct oral anticoagulants (DOACs), pharmacists should be knowledgeable and abiding by evidence-based practice. We aim in this study to assess the knowledge and practices of practicing hospital and community pharmacists in Qatar regarding DOACs and their reflection on the dispensing and patient education. A prospective cross-sectional survey was developed. It included questions on demographic and professional characteristics. Additionally, it evaluated the awareness regarding safety, efficacy, and dispensing of DOACs. Lastly, a separate question was used to address the participant’s satisfaction with their knowledge. A total response were received from 211 pharmacists participating in the survey. Overall awareness score was moderate (41.6% ± 26%). These scores were in alignment with participants’ self-satisfaction with knowledge on DOACs (72% of participants were not satisfied). Being a clinical pharmacist, of male gender, and with a board certification were factors associated with increased awareness on DOACs. Results from this survey point to the importance of having more educational activities in order to improve pharmacist’s knowledge of DOACs.The authors disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: The publication of this article was funded by the Qatar National Library.Scopu
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