Controlled Crystallization of Chlorpropamide from Surfactant and Polymer Solutions

Chlorpropamide crystals were prepared by recrystallization technique from alcoholic solution of Polysorbate 80, Polyethylene Glycol and Polyvinyl-pyrrolidone. Marked enhancement in the dissolution rate of the formed crystals was observed. The enhancement was found to be a function of molecular weight of the polymer used Thus the percentage drug dissoluted after three hours at 10% polymer concentration was found to be 37, 41 and 55% for Polyvinylpyrrolidone K30 K64 and K90 respectively, and 27, 31, 32% for Polyethylene Glycol 4000, 6000, and 20000 respectively. This may be due to possible solubilization effect of the surfactant and polymers. Also solution of the polymer may produce an ultrafine crystals of the drug, mainly due to the difficulty of growth of the crystals in highly viscous medium of the polymer. Infrared study revealed that no polymorphic change or complex formation had occurred.     

Accelerated Degradation of Recycled Plastic Piling in Aggressive Soils

Fiber-reinforced polymer composites represent an alternative construction material without many of the performance disadvantages of traditional materials. The use of fiber-reinforced polymer as a pile material can eliminate deterioration problems of conventional piling materials in waterfront environments and aggressive soils. This paper presents the preliminary results of an experimental study conducted to assess the durability of piling made of recycled plastics in aggressive soils for long-term usage in civil infrastructure applications. An accelerated testing protocol permitting prediction of the behavior of plastic piles was developed. Specimens were exposed to solutions with fixed acidic, basic, and neutral pH at elevated temperatures. Compressive strength was used as an index to quantify the degradation of the specimens. An Arrhenius model was used to predict the service life of the product.     

Cationic Polymer Modified Mesoporous Silica Nanoparticles for Targeted siRNA Delivery to HER2+ Breast Cancer

In vivo delivery of siRNAs designed to inhibit genes important in cancer and other diseases continues to be an important biomedical goal. A new nanoparticle construct that is engineered for efficient delivery of siRNA to tumors is now described. The construct comprises a 47‐nm mesoporous silica nanoparticle core coated with a crosslinked polyethyleneimine–polyethyleneglycol copolymer, carrying siRNA against the human epidermal growth factor receptor type 2 (HER2) oncogene, and coupled to the anti‐HER2 monoclonal antibody (trastuzumab). The construct is engineered to increase siRNA blood half‐life, enhance tumor‐specific cellular uptake, and maximize siRNA knockdown efficacy. The optimized anti‐HER2 nanoparticles produce apoptotic death in HER2 positive (HER2⁺) breast cancer cells grown in vitro, but not in HER2 negative (HER2^?) cells. One dose of the siHER2–nanoparticles reduces HER2 protein levels by 60% in trastuzumab‐resistant HCC1954 xenografts. Administration of multiple intravenous doses over 3 weeks significantly inhibits tumor growth (p < 0.004). The siHER2‐nanoparticles have an excellent safety profile in terms of blood compatibility and low cytokine induction, when exposed to human peripheral blood mononuclear cells. The construct can be produced with high batch‐to‐batch reproducibility and the production methods are suitable for large‐scale production. These results suggest that this siHER2‐nanoparticle is ready for clinical evaluation.     

An analytical model for silicon MIS/IL solar cells to optimize cell parameters through thermal annealing

A model has been developed which simulates the effect of cell parameters in order to optimize them by controlling the fabrication conditions, namely, annealing time and annealing temperature. Calculation of the efficiency as a function of surface states density D_it, positive fixed oxide charge density Q_f and mobile charge density Q_m, that depend on anealing conditions are carried out. A compromise between D_it and Q_m for different anealing temperatures for high performance cells has been investigated.     

BREAKING WATER-IN-CRUDE OIL EMULSIONS BY NOVEL DEMULSIFIERS BASED ON MALEIC ANHYDRIDE-OLEIC ACID ADDUCT

This paper mainly concentrates on synthesis of ten novel demulsifiers and investigate their demulsification efficiency. The demulsifiers were derived from oleic acid-maleic anhydride adduct (OM), which prepared by reaction of oleic acid with maleic anhydride. The reaction was carried out between the OM adduct and the following compounds to form the correspondence demulsifiers; triethanolamine (OMTEA), triglycerol (OMTG), cetylamine (OMCA), triethanolamine with lauryl alcohol (OMTEA-LA), triethanolamine with cetylamine (OMTEA-CA), polyethylene glycol 600 (one mole (OM e.o. 13.6)), polyethylene glycol 600 (two moles (OM e.o. (13.6) 2)), polyethylene glycol 1000 (OM e.o. 22.7), triethanolamine with polyethylene glycol 1000 (OMTEA e.o. 22.7) and triethanolamine with polyethylene glycol 6000 (OMTEA e.o. 136.4). The chemical structures of the OM adduct and some selected demulsifiers were confirmed by ¹H NMR and FTIR. A wide range of demulsifier properties can be obtained by changing the degree of functionalization of the base molecules. The demulsification efficiency of these demulsifiers was tested on w/o emulsions with 10, 30 and 50% water content. From the obtained data, it has found that, the investigated demulsifiers are having a great potential to break the w/o emulsions completely in different times. The (OMTEA e.o. 136.4) was exhibited the minimum time taken to complete separation. The data were discussed on the light of the chemical structure of the demulsifiers and the factors, which effect on the demulsification process.     

Preparation and properties of CdS thin films prepared on cold substrate as a window layer for solar cells

CdS films, usually, prepared on hot substrate at temperature range from 180 to 220°C. The electrical properties of the films are dependent on many parameters such as film thickness, deposition rate, film structure and substrate temperature. To control all these parameters to get film resistivity suitable for manufacturing solar cells, it needs a lot of precautions. CdS prepared on cold substrate could be the solution for this problem. Evaporation of CdS film at constant evaporation rate, then annealed in open air up to 600°C according to the film thickness. The resultant film have been studied. The properties of the films were comparable to the films prepared by the other methods with less control complexity.     

Prevention of tooth hypersensitivity caused by the hydrodynamic action of zinc phosphate and composite resin luting cements (SEM) study

This study was done to determine the role of cement liner as a reducing factor to the fluid movement in order to prevent tooth hypersensitivity according to the hydrodynamic theory during cementation of crowns. A total of fourty freshly extracted intact lower molar were selected for this study. After conventional tooth preparation the teeth were sub-divided into four equal groups to identify the role of cement liner in preventing the penetration of used cement into the dentinal tubules. Scanning electron microscopic study proved the efficiency of glass ionomer liner on preventing cement penetration into the dentinal tubules.     

What constitutes cerebral palsy?

OBJECTIVE: To determine whether a newly developed disability scale for patients with neck pain demonstrated acceptable reliability and validity. METHODS: Testing was conducted using three different samples of patients with neck pain (n = 162). Test-retest reliability of the scale was carried out on the same day with one sample (n = 39), and between-day reliability was carried out with another (n = 21). Differential item functioning with regard to the influence of gender and age was carried out with these two patient groups, as was construct validity. Responsiveness was measured using patients participating in a clinical trial involving patients with chronic neck pain (n = 102). Additionally, scale scores were compared with a wide range of physical measurements using the patients in the clinical trial. RESULTS: Short-term, between-day and postal questionnaire reliability coefficients were all extremely high. The Cronbach's alpha coefficient for internal consistency was 0.9 for the entire scale, and the coefficients for individual items were all greater than 0.88. Disability scale scores correlated strongly to pain scores as well as to doctor and patient global assessments, indicating good construct validity. Relative changes in disability scores demonstrated a moderately strong correlation to changes in pain scores after treatment. Scale scores correlated weakly to all physical measurements. CONCLUSIONS: The disability scale demonstrated excellent practicality and reliability. The scale accurately reflects patient perceptions regarding functional status and pain as well as doctor's global assessment and is responsive to change over long periods of time. We feel that this scale can be a valuable tool for the assessment of patients in future clinical trials and quality of care studies.     

Microstructure-microhardness relationships in friction stir welded AA5251

Quantitative microstructural studies using optical and electron microscopy were carried out to determine the grain size and intermetallic particle distributions in various locations of friction stir welds in AA5251 to study their influence on the microhardness. Grain-boundary strengthening, (using Hall-Petch relation) was found to be the dominant factor controlling weld hardness within the thermomechanically-affected zone (TMAZ), yet with a minor increase in the Hall-Petch intercept from the Al–Mg alloys literature values. This deviation was associated with solid-solution strengthening resulting from the dissolution of Mg₂Si particles during welding. A contribution from precipitate strengthening accounted for deviations from the overall Hall-Petch relationship. This was linked to the formation of submicron Al₆(Fe,Mn) particles observed within the TMAZ grains, varying in density with position in the weld, and accordingly their strength contribution. Differential Scanning Calorimetry (DSC) was used to quantify the strengthening contribution of the dislocation stored energy in the TMAZ of the weld. Although significant stored energy was detected, this was mostly due to the presence of geometrically-necessary (non-strengthening) dislocations and did not contribute to hardness.     

Characterization of optical,thermal and electrical properties of SWCNTs/PMMA nanocomposite films

The optical, thermal and electrical behavior of single-wall carbon nanotubes (SWCNTs)/poly(methyl methacrylate) (PMMA) composite are studied as a function of SWCNTs concentration. The nanocomposites were prepared in the form of films by solution casting technique. The concentrations of SWCNTs in SWCNTs/PMMA films were 0, 0.5, 1, 1.5, 2, 3.5, 5, 7.5, and 10 wt%. High-resolution transmission electron microscopy showed that SWCNTs doped in PMMA is less fragmented as compared to the powder SWCNTs. This is due to the interactions with polymers as well as the fabrication method. X-ray diffraction patterns of SWCNTs/PMMA composite films indicated that there is no covalent interaction between SWCNTs and PMMA. In addition, it demonstrates a homogeneous dispersion of SWCNTs in PMMA matrix. The optical properties of SWCNTs/PMMA films of SWCNTs concentration from 0 to 2.0 wt% have shown that the absorption intensity of the composite was enhanced ≈8.5 times as compared to the plain PMMA. Photoacoustic spectroscopy technique was used as a powerful and non-destructive tool to determine the thermal diffusivity (α), thermal effusivity (e) and thermal conductivity (k). The composites exhibited ≈160 % improvement in k at 2.0 wt%. Furthermore, the DC electrical conductivity measurements of SWCNTs/PMMA showed that the percolation threshold value was about 2.0 wt% of SWCNTs loading.