Effect of Storage Conditions on the Hardness, Disintegration and Drug Release from Some Tablet Bases

The effect of storage at relatively high temperature and humidity on tablets prepared from different bases was studied for up to eight weeks. Drug release from tablets was followed by measuring the concentration of a marker (amaranth) in the dissolution medium. Lactose and mannitol based tablets showed an increase in hardness and disintegration time, and a decrease in the initial rate of drug release. Sorbitcl based tablets, stored under 50°C/50% relative humidity (R.H.), showed a decrease in hardness and slower disintegration and dissolution. When stored under 40°C/90% R.H., the tablets were completely deformed within three days. Tricalcium phosphate and cellulose-based tablets did not show any storage related changes in hardness, disintegration or drug release.     

Safeguarding Cloud Computing Infrastructure: A Security Analysis

Cloud computing is the provision of hosted resources, comprising software, hardware and processing over the World Wide Web. The advantages of rapid deployment, versatility, low expenses and scalability have led to the widespread use of cloud computing across organizations of all sizes, mostly as a component of the combination/multi-cloud infrastructure structure. While cloud storage offers significant benefits as well as cost-effective alternatives for IT management and expansion, new opportunities and challenges in the context of security vulnerabilities are emerging in this domain. Cloud security, also recognized as cloud computing security, refers to a collection of policies, regulations, systematic processes that function together to secure cloud infrastructure systems. These security procedures are designed to safeguard cloud data, to facilitate regulatory enforcement and to preserve the confidentiality of consumers, as well as to lay down encryption rules for specific devices and applications. This study presents an overview of the innovative cloud computing and security challenges that exist at different levels of cloud infrastructure. In this league, the present research work would be a significant contribution in reducing the security attacks on cloud computing so as to provide sustainable and secure services.     

A study on optimization of acid sites concentration versus pore dimensions in modified solid acid catalysts for biodiesel production

The acid sites concentration of silica sulfuric acid was optimized against pore dimensions depending on the intensity of silanol groups as a key for binding modifier molecules. The texturally modified rice husk silica, of determined intensity of silanol groups, was functionalized with different loadings of SO₃H groups to produce solid acid catalysts with different concentrations of acid sites and different sizes of the pore systems. The catalysts were employed in trans-esterification of waste-cocking oil. The obtained optimum catalytic activity was attributed to the proper compensation between acid sites intensity and pore dimensions. The estimated TOF for methyl ester production was found to decrease with the increase of SO₃H loading on the catalyst surface. The role of compatibility of the reactants phase with the catalyst nature could be validated by the observed much higher activity of sulfonated lignin in the studied esterification reaction than the modified RHS-acid catalysts under study.     

Regression of brown tumor of the maxilla in a patient with secondary hyperparathyroidism after a parathyroidectomy

Brown tumors or osteoclastomas are erosive bony lesions arising as a complication of hyperparathyroidism. In patients with end‐stage renal disease, brown tumors are uncommon skeletal manifestations that are usually seen in severe forms of secondary hyperparathyroidism. Initial treatment involves the correction of hyperparathyroidism, which usually leads to regression of the tumors. We report a case of brown tumors of the maxilla in a 24‐year‐old female referred to us by a local hospital, where she had been on regular hemodialysis for >10 years. After a complete biochemical and radiological workup, she underwent a total parathyroidectomy, which subsequently resulted in significant regression of her tumor.     

Crystallization kinetics of PE‐b‐isotactic PMMA diblock copolymer synthesized using SiMe2(Ind)2ZrMe2 and MAO cocatalyst

Polyethylene‐b‐poly(methyl methacrylate) (PE‐b‐PMMA) diblock copolymer has important interfacial applications. Hence, a PE‐b‐isotactic PMMA diblock copolymer was synthesized using SiMe₂(Ind)₂ZrMe₂ and MAO cocatalyst. The polymerization mechanism and the origin of PMMA isotacticity were duly explained. An appropriate nonisothermal Avrami‐Erofeev crystallization model was developed to compare the crystallization kinetics of the above copolymer with that of a PE homopolymer. For both polymers, the model well matched the entire differential scanning calorimeter crystallinity profile, notably for a single Avrami‐Erofeev index, and predicted cylindrical crystal growth. This model particularly overcomes the limitations of the published nonisothermal crystallization models, and provides interesting insight into PE crystallization. The PMMA block significantly decreased the heats of crystallization and fusion, % crystallinity, and the relative crystallization function; increased the nonisothermal crystallization rate constant; and introduced minimal dilution effect whereas the PE block formed a continuous or percolated phase. This study correlates catalyst structure, copolymer block tacticity, and PE nonisothermal crystallization and melting behavior. © 2012 American Institute of Chemical Engineers AIChE J, 59: 200–214, 2013     

New Improved Thermoluminescence Magnesium Silicate Material for Clinical Dosimetry

Silicon - Magnesium silicate has been prepared by a precipitation technique. This composite structure was proven by different tools, XRD, TGA&DTA, FTIR, and XRF. Magnesium silicate was...     

Parametric study of biodiesel production from used soybean oil

Biodiesel, an alternative diesel fuel derived from vegetable oil, animal fat, or waste vegetable oil (WVO), is obtained by reacting the oil or fat with an alcohol (transesterification) in the presence of a basic catalyst to produce the corresponding mono‐alkyl esters. In this work, the effect of the catalyst KOH‐to‐WVO ratio, ethanol concentration, and time of reaction on the biodiesel yield were investigated. The transesterification reaction was performed at a constant temperature (35 °C) in order to minimize the cost of heating and ethanol evaporation. A 2³ complete factorial design on biodiesel yield (Y) was performed using low and high levels of operating variables: KOH concentration (9–14 g/L), ethanol concentration (30–40 vol‐%) and time (30–40 min). The complete factorial model that can be used to fit the data was determined. The model shows that interactions exist among the parameters and that the parameters, or factors, do not operate independently on the response (biodiesel yield). The highest yield was obtained in the first 30 min of reaction time. The results indicate that the highest yield was 78.5 vol‐% using a KOH‐to‐WVO ratio of 12 g/L and 30 vol‐% ethanol. The ASTM tests indicate that the biodiesel properties are within the biodiesel standard limits.     

Recovery of residual emulsifiable oil from waste water by flotation

A source of waste‐water pollution in machining is the lubricating/cooling fluid used. This study investigates the application of the flotation technique for the removal of emulsifiable oil. Research has been carried out on a process of selective separation of oil using mixtures of anionic/nonionic surfactants as collectors and a cationic surfactant as a de‐emulsifier (coagulant). The behaviour of the mixtures at the aqueous solution‐air interface has been studied, and the critical micelle concentration, efficiency, effectiveness, minimum surface area, and free energy of micellisation determined. The effect of the optimum mole fraction of the mixtures on oil separation has been discussed from the point of view of physical parameters. The selectivity achieved can be explained in terms of surfactant concentration and the structure of the micelles.