Sodium Hydroxide

At present, the production of wood composites mainly relies on the petrochemical-based and formaldehyde-based adhesives such as phenol-formaldehyde (PF) resins and urea-formaldehyde (UF) resins, which are non-renewable and therefore ultimately limited in supply.

Response surface methodology (RSM) was used to optimize the conditions for the production of endo ␤-1,4 glucanase, a component of cellulase by Aspergillus nidulans MTCC344 under solid state fermentation, using bagasse as the chief substrate. A four-factor-five-level central composite design was employed for experimental design and analysis of the results. Maximum cellulase activity (CMCase was 28.96 U g −1) can be attained at the optimum conditions, 16.8 mm bagasse bed height, 60% moisture content, pH 4.25 and temperature 40 • C in the solid state fermenter. These data were rather close to the experimental results obtained (CMCase was 28.84 U g −1). A. nidulans MTCC344 was able to hydrolyze pretreated bagasse completely after 8 days of incubation with significant endo ␤-1,4 glucanase activities. The results of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) of bagasse showed structural changes through pretreatment, in favor of enzymatic hydrolysis. Bagasse with alkali pretreatment using sodium hydroxide is a source of lignocelluloses able to improve the yield of endo ␤-1,4 glucanase by the strain of A. nidulans. The endo ␤-1,4 glucanase produced during the bioconversion of cellulose to glucose by A. nidulans MTCC344 is strongly dependent on the pretreatment given before hydrolysis.

ZnO nanoparticles have been synthesized by ultrasonic irradiation of an aqueous-alcoholic/aqueous-alcoholic-ethylenediamine (EDA) solutions of zinc nitrate and sodium hydroxide. ZnO nanoparticles possess hexagonal wurtzite structures and they exhibit special photoluminescence properties with a red-shift of 22 nm in UV emission band. It is found that the ultrasonic irradiation time and the solvents both influence the growth mechanism and optical properties of ZnO nanoparticles. The possible growth mechanism of ZnO nanoparticles formation by sonochemical method has been tried to discuss.

Sodium n-propoxide and sodium iso-propoxides were synthesized and characterized. Thermal decomposition of these compounds was studied using thermogravimetric technique (TGA) coupled with mass spectrometry (MS) under non-isothermal and isothermal conditions. Various analytical techniques namely atomic emission spectroscopy (AES), infrared spectroscopy (IR), powder X-ray diffraction (XRD), elemental and volumetric analyses were employed to characterize these compounds and their decomposition residues. Kinetic parameters, namely, the activation energy and pre-exponential factor were deduced from the dynamic TGA and MS data. The activation energies derived from isothermal runs for the thermal decomposition of sodium n-propoxide and sodium iso-propoxide were 151.45 ± 2.16 and 128.07 ± 3.44 kJ mol À1 , respectively. Decomposition of sodium n-propoxide and sodium iso-propoxide results in the formation of gaseous products of saturated and unsaturated hydrocarbons leaving behind residue consisting of sodium carbonate, sodium hydroxide and free carbon.

AbstractÐSurfactant-modi®ed zeolites (SMZ) have drawn recent attention as sorbents due to their removal of multiple types of contaminants and low material cost. However, like most sorbents, SMZ has a ®nite sorption capacity for dierent contaminants. The potential applications, economics, and eciency of SMZ as a sorbent are related to the ability to regenerate the material. This paper reports several methods to regenerate chromate-and perchloroethylene-saturated SMZ. Regeneration of chromate-saturated SMZ was achieved by¯ushing with a sodium carbonate/sodium hydroxide solution. However, this high-pH solution increased the counterion competition for chromate sorption sites and decreased the chromate sorption capacity of the regenerated SMZ. As an alternative regeneration method, chromate sorbed to SMZ was reduced to Cr(III) in situ using sodium dithionite solution. Although reduction with dithionite restored the chromate sorption maximum, the chromate sorption intensity was lowered, possibly due to the competition by sulfate (generated from oxidation of dithionite) for chromate sorption sites. Carbonate-regenerated SMZ showed no loss of sorption anity for perchloroethylene (PCE) compared to virgin SMZ. Air sparging of PCE-saturated SMZ fully regenerated the SMZ. The results show that it is possible to regenerate and re-use SMZ following saturation with anionic or nonpolar organic contaminants. 7

This report describes separation and detection of chlorophenoxy acid herbicides spiked in drinking water by the technique combining solid-phase extraction, fieldamplified sample stacking, capillary electrophoresis, and potential gradient detection. The herbicide solution (400 mL) was concentrated to 0.1 mL by the solid-phase extraction procedure. The buffer containing 3 mM ammonia and 0.3 mM hydroxypropyl-bcyclodextrin was adjusted to pH 9.0 with ammonia. The sample solution was injected into the capillary to 30% of the whole length, and 29 kV and 9 kV were employed for field-amplified sample stacking and separation, respectively. The herbicides were baseline separated and the detection limits with the above combined techniques were in the range of 1-4610 22 ng/mL.

Lignocelluloses industrial waste flour of olive husk powder (LCF) was utilized as reinforcement in carboxylated nitrile butadiene rubber (XNBR)/Polyamide-12 (PA-12) thermoplastic elastomer composites. To improve the bonding quality between the LCF and the blend, the powder was chemically treated by two means, the former is the treatment with toulene-2–4-diisocyanate (TDIC), and the latter is mercerization with sodium hydroxide followed by neutralization with acetic acid. The untreated and chemically treated powders were analyzed with attenuated total reflectance infrared spectroscopy (ATR-IR). The morphology of the powders before and after treatment was studied with scanning electron microscopy (SEM). The LCF reinforced composites were prepared using computerized Haake internal mixer coupled with rheometer. The processing conditions were 178°C and rotor speed of 80- round per minute for 7 min. The melt mixing process was monitored by the torque-time plastograms of the Haake internal mixer. The development of the stock temperature during the mixing process was monitored using the rheometer of Hakke internal mixer. The structural changes of the XNBR/PA-12 composites were inspected by SEM and attenuated ATR-IR spectroscopy. The influence of the modified filler on the toughness and hardness of the prepared samples are reported. The resistance of the prepared composites to water and toluene swelling are evaluated as well.

The solubility of wheat gluten may be increased greatly by treatment with 0.25 M sodium hydroxide. At temperatures of 40°C and above, the solubility of the protein exceeds 100 mg/ml in a reaction time of 6 hr or less. The products from the reaction of 60°C and 80°C were darker than the original gluten and had an unpleasant odour of H 2 S on dissolution in water. They also contained traces of lysinoalanine. The 40°C reaction product was about the same colour as gluten, and its solutions in water did not smell of H S. Reaction of gluten at 20°C also caused a large increase in solubility, but after 24 hr the solubility was only 77 mg/ml. This product was also of the same colour as gluten, and did not smell of H 2 S in solution. Neither the 20°C nor the 40°C products contained detectable traces of lysinoalanine. For reasons of flavour, colour, lysinoalanine content and economy of time, the optimum reaction conditions are 6 hr at 40°C.

The efficiency of raw wheat and soybean straws, corn stalks and corn cobs in removing different heavy metal ions from simulated contaminated water was studied. The investigated adsorbents have shown different adsorption capacities for copper, nickel, cadmium and lead ions. All of them, except for corn cobs, adsorbed copper ions well. Corn cob and wheat straw adsorbed cadmium and nickel ions well. As for lead ions soybean straw and corn stalks showed good adsorption capacity. In order to increase the adsorption capacities and decrease the leaching of extractive matters from all investigated biomasses, they were modified with (1) formaldehyde in acidic medium, (2) sodium hydroxide both with and without previous modification with formaldehyde, (3) acid solution or (4) only were water-washed. The effects of these treatments were evaluated in copper adsorption experiments. Treatments with formaldehyde, sulphuric acid and 5% NaOH were not advisable for investigated adsorbents. Adsorbents modification with 1% NaOH or water washing adsorbents gave good results, but the native (raw) materials were still quite efficient. In order to prevent organic matters leaching from biomasses during adsorption the washing of lignocellulosic materials is applied as it is the cheapest and the most suitable process.

A series of biochemical, staining and electron microscopy techniques were utilized to investigate the mechanisms of C-and G-banding. These led to the following conclusions. I. The treatment of fixed chromosomes with 0.07 N NaOH for 30 to 180 set removes from 16 to 81% of the DNA from the chromosomes. 2. On average, the complete C-band technique removes 60% of the DNA. 3. This DNA is preferentially extracted from the non-C-band regions. 4. In marked contrast to this, all G-band techniques (except 1) removed less than 9 o,, of the chromosomal DNA. 5. Most of the G-band techniques, including those using trypsin, remove very little protein from the chromosomes. 6. Feulgen staining indicated that neither C-nor G-banding can be explained on the basis of different amounts of DNA along the length of the chromatid. 7. Treatment of chromosomes witkalkali or prolonged treatment with trypsin tends to destroy G-bands, while C-bands remain. 8. The combined use of acridine orange and Giemsa staining indicate that, (a) repetitious DNA in situ renatures in seconds while non-repetitious DNA renatures in minutes; (6) Neither C-nor G-banding depends upon the differential renaturation of DNA for its effect. 9. G-banding is more delicate and relatively mild conditions allow staining of both C-and G-bands. To obtain only C-bands the chromosome must be treated more harshly to disrupt or destroy the G-bands. 10. DNA-non histone protein interactions probably play an important role in the production of both C-and G-banding.

A new system has been developed for removal of chloride contamination from kraft process liquors. The compact, skid-mounted system which utilizes ion exchange columns only 24 inches in height, is shown to be capable of removing 90-99% of the chloride from a wide variety of sources including dissolved ESP catch, oxidized white liquor, spent bleach scrubber liquors, spent ion exchange demineralizer regenerants and caustic soda makeup. By removing chloride contamination, these liquors can be recycled to kraft recovery without causing a chloride buildup. By lowering the chloride content in kraft liquors, the sticky temperature of recovery boiler deposits can be significantly increased, which should lead to reduced pluggage and boiler down-time. Selectivity of the ion exchanger for chloride is extremely high and recovery of other chemicals such as sodium sulfate, sodium carbonate and sodium hydroxide is demonstrated to be typically 92-98%. Regeneration of sodium chloride from the resin is achieved with only water (ie. no chemicals), so that operating costs are negligable.

Sulfur dioxide, N,N-diallyl-N-carboethoxymethylammonium chloride and the hydrophobic monomers N,N-diallyl-N-dodecylammonium chloride or N,N-diallyl-N-octadecylammonium chloride were cyclocopolymerized in dimethyl sulfoxide using azobisisobutyronitrile (AIBN) as the initiator to afford water-soluble cationic polyelectrolyte (CPE) having five-membered cyclic structure on the polymeric backbone. The CPE on acidic (HCl) hydrolysis of the pendent ester groups gave the corresponding cationic acid salt (CAS) which was converted to the anionic polyelectrolyte (APE) by treatment with sodium hydroxide. The solution properties of the CPE and APE containing varying amount of the hydrophobic monomers in the range 0 -10 mol% were investigated by viscometric techniques. The polymers showed that concentration (C p HA ) of less than 1 wt% was required for the manifestation of hydrophobic association, and displayed significant hydrophobic association in salt (NaCl)-free as well as salt-added solutions. q

Background: Lipid-based drug delivery systems are widely used for enhancing the solubility of poorly water soluble drugs in the gastro-intestinal tract. Following oral intake, lipid systems undergo digestion in the stomach as well as the intestine. Lipolysis is here a complex process at the oil/water interface, influenced by numerous factors. Purpose: To study the digestibility of nine excipients often used in lipid-based drug delivery systems. In addition, we introduced a mathematical model to describe in vitro lipolysis kinetics. A relative lipolysis half life was defined using the reference excipient medium-chain triglycerides. Methods: Using pH-stat equipment, the NaOH consumption was determined in an in vitro lipolysis assay. Results: We identified two classes of excipients. Some additives were partially hydrolysed, whereas other excipients displayed complete lipolysis. For the latter class, a simplified mathematical model provided a good first approximation of initial lipolysis kinetics. Conclusions: Digestion characterization of excipients is important for the development of lipid-based delivery systems. The applied kinetic model and the concept of a relative lipolysis half life seemed to be promising tools for comparing in vitro lipolysis results.

Dihydroboration of propargyl bromide with 9-BBN-H followed by treatment of the adduct with aqueous sodium hydroxide aords the hydroxy(cyclopropyl)borate complex (1), which undergoes ecient palladiumcatalyzed cross-coupling to produce a variety of aryl and vinyl cyclopropanes (2) in good to excellent yields. #

Medical-grade poly(vinyl chloride) (PVC) was chemically modified to study how the incorporation of monovalent silver influences Pseudomonas aeruginosa adhesion and colonization. The modification investigated consisted of a radio frequency-oxygen (RF-O 2 ) glow discharge pre-functionalization, followed by a two-step wet-treatment in sodium hydroxide and silver nitrate solutions. X-ray photoelectron spectroscopy (XPS) analysis and contact angle measurements were used to investigate the chemical nature and surface wettability of the films following each step of the modification. XPS analysis proved that the RF-O 2 plasma pre-functionalization of native PVC reproducibly increased the amount of functional groups representative of PVC additives, including ether/alcohol, esters and carboxyl groups. More specifically, we demonstrated that the O2 % CQO groups representative of the phthalic ester and zinc carboxylate additives identified for native PVC increased by two-fold following the RF-O 2 plasma pre-functionalization step. Although RF-O 2 pre-functionalization did not have an effect on the silver content of the NaOH/AgNO 3 treated substrates, such a modification was necessary for biomaterial products that did not have reproducible surfaces amongst production lots. XPS analysis also demonstrated that saponification with sodium hydroxide (NaOH) of esters, like those of the phthalic ester additives of PVC is a simple, irreversible method of hydrolysis, which produced sodium carboxylate and sodium phthalate salts. Exposure of native PVC to NaOH resulted in an increased surface hydrophilicity (from ca 90 to ca 60 ) due to dechlorination. XPS analysis following further incubation in silver nitrate demonstrated that silver ions can be trapped when the sodium of sodium carboxylate is replaced by silver after performing a second treatment with a monovalent silver-containing solution. The creation of silver salt on native PVC resulted in an ultra-hydrophobic (>120 ) surface. The chemical modifications using NaOH and AgNO 3 wet treatments completely inhibited bacterial adhesion of four strains of P. aeruginosa to both native and oxygen-pre-functionalized PVC, and efficiently prevented colonization over longer periods (72 h). Our results suggest that surface modifications that incorporate silver ions would be extremely effective at reducing bacterial colonization to medical devices. r

The effects of treating the alloy powder of an electrode with 6 M sodium hydroxide solution containing y M (y ¼ 0.0, 0.005, 0.01, 0.02, 0.03, 0.05) sodium borohydride (NaBH 4 ) on the kinetics of hydrogen evolution reaction (HER) at the Mm(B 5 ) 1.15 hydride electrode (Mm ¼ cerium-rich mischmetal; B 5 ¼ Ni 3.6 Co 0.7 Mn 0.4 Al 0.3 ) are described. Several kinetic parameters are considered, including Total, Volmer and Tafel overpotentials, exchange current densities and activation energies of the elementary reactions. Such parameters are investigated by measuring the overpotential decay immediately after the interruption of an applied cathodic current. The effects of NaBH 4 treatment and temperature on the mechanism of the HER are analysed on the basis of the dependence of the Volmer and Tafel overpotentials on current density. The effect of the NaBH 4 concentration on the performance of the hydrogen storage alloy as a negative electrode material in nickel-metal hydride batteries and/or alkaline fuel cells is discussed from the standpoint of relative velocity of the elementary reactions.

The corrosion behavior of unalloyed and alloyed ductile irons (as cast, annealed, and cold worked) in sea water, dilute sulfuric acid, and dilute sodium hydroxide solutions was assessed. Specimen history had a significant effect on the corrosion potential except in ductile iron alloyed with Ni. When the specimens were subjected to different levels of cold working, the corrosion rate was influenced by both the history and the medium. Temperature had a significant effect on the corrosion rate except in the case of unalloyed ductile iron. Factorial experiments indicated that the cold-worked samples were more sensitive to the effect of temperature and composition on the corrosion rate as compared to annealed and as-cast samples. The medium had a significant effect on the corrosion rate in all the cases.

Background: Esophagus tissue engineering holds promises for esophageal replacement after severe caustic injuries. The aim of this study was to determine whether viable esophageal epithelial cells could be isolated from an esophagus exposed to varying concentrations of alkali with regard to number, viability, and morphology during in vitro culture. Methods: Ovine esophagi were exposed to phosphate-buffered saline 2.5%, 15%, or 25% sodium hydroxide (NaOH). The effect of NaOH concentrations on epithelial damage was assessed histologically. Esophageal epithelial cells were then isolated, and cell count and viability were investigated. Finally, cell number, viability, and morphology of esophageal epithelial cells were determined for 24 days of in vitro culture. Results: Histologic analysis showed a progressive destruction of the epithelium proportional to increasing NaOH concentrations. Esophagi treated with phosphate-buffered saline and 2.5% NaOH showed significantly higher viable cell counts after isolation and culture in comparison with those treated with 15% to 5% NaOH. Conclusion: The evidence presented in this study indicates that epithelial biopsies from an esophagus exposed to low concentrations (2.5%) of NaOH will still yield large numbers of viable cells suitable for tissue engineering applications. In cases of exposure to higher concentrations (15%-25%), alternative cell sources for epithelial regeneration, such as stem cells, will be necessary for tissue engineering applications.

The first stages of the synthesis of ZnO nanoparticles by forced hydrolysis of ZnCl2 with NaOH and water in ethanol have been investigated using UV-Vis spectrophotometry. At sufficiently low water concentrations, focusing of the nanoparticle size distribution was observed during the nucleation and growth phase, followed by a defocusing phase when coarsening becomes significant. During nucleation and growth, only the smaller particles grow while the larger particles have an essentially zero growth rate, indicating that the growth rate decreases rapidly with particle size. As the average particle size remains nearly constant in this regime, the absorbance increase with time can be used to determine the nucleation rate. The nucleation rate was found to depend on both the water concentration and the reactant concentrations. The results are discussed in terms of a mechanism where water determines the precursor formation kinetics thus controlling the nucleation rate.The first stages of the synthesis of ZnO nanoparticles by forced hydrolysis of ZnCl2 with NaOH and water in ethanol have been investigated using UV-Vis spectrophotometry. At sufficiently low water concentrations, focusing of the nanoparticle size distribution was observed during the nucleation and growth phase, followed by a defocusing phase when coarsening becomes significant. During nucleation and growth, only the smaller particles grow while the larger particles have an essentially zero growth rate, indicating that the growth rate decreases rapidly with particle size. As the average particle size remains nearly constant in this regime, the absorbance increase with time can be used to determine the nucleation rate. The nucleation rate was found to depend on both the water concentration and the reactant concentrations. The results are discussed in terms of a mechanism where water determines the precursor formation kinetics thus controlling the nucleation rate. Electronic supplementary information (ESI) available: Figures illustrating the time dependence of (a) the absorbance maximum and (b) λ1/2 for different [NaOH]/[ZnCl2] ratios at a fixed water concentration of 100 mM and 1 mM ZnCl. See DOI: 10.1039/c0nr00439a

Raman spectroscopy, plasma emission spectroscopy, electron spectroscopy for chemical analysis (ESCA), elemental analysis, solution conductivity and pH, were used to characterise the solutions and the acid, base and silane-treated E-glass fibres. Strong acids and bases induced an ion exchange reaction, which caused large quantities of aluminium and calcium to be leached from the E-glass surface. Samples treated with strong bases were found to have large quantities of sodium on the E-glass fibre surface; this came from the sodium hydroxide used to treat the fibres and from the bulk of the fibre. A cyclic isocyanurate silane, which was only partially soluble in water, was detected on the E-glass surface. A cationic amino-functional silane ester with a long organic chain did not completely hydrolyse in an aqueous solution adjusted to pH=4. The solution concentration, which gave the maximum amount deposited, was different for each silane tested.

The effect of pulsed flow on mass transfer in an electrolytic reactor was investigated using carbon felt electrode arranged in a way that the electrolyte and the current flows were parallel to each other. In these experiments, a solution of potassium ferri-and ferro-cyanide with inactive compound of sodium hydroxide was employed. The electrolyte superficial velocity was in the range 4.29 × 10 −4-18.2 × 10 −4 m s −1. The frequency and the normalised amplitude of the pulse in the flow rate were changed in the range 0.17-3.55 s −1 and 3.5 × 10 −3-1.0 × 10 −2 m, respectively. The experiments showed that the pulsed flow increased significantly the transfer of reacting ions onto the electrode surface up to a frequency of 1.5 s −1 and over this frequency the current ratio was effected slightly with increasing frequency. The increasing amplitude also had a positive effect on transfer rate, but not as pronounced as the frequency. An increase in the mass transfer rate between approximately 6.8 and 33.5 times of those of the flow with no pulse was obtained, depending upon the experimental conditions.

A continuous flow sensor for the determination of thiamine was constructed by using controlled-reagent-release technology in a FIA-CL system. The analytical reagents, luminol and KIO 4 , were both immobilized on an anion-exchange column. The CL signal produced by the reaction between luminol and KIO 4 , which were eluted from the column through H 2 O injection, was decreased in the presence of thiamine. The decreased CL intensity was linear with thiamine concentration in the range 3.3 pmol ml − 1 -6.7 nmol ml − 1 ; and the limit of detection was 1.0 pmol ml − 1 (3 ). The whole process, including sampling and washing, could be completed in 0.5 min with a relative standard deviation of less than 3.0%. The flow sensor showed remarkable stability and could be easily reused over 80 h. The sensor proposed was tested in determination of thiamine in pharmaceutical preparation and human urine samples.

There is a gap in the literature concerning the chemical effects that household products may produce on human remains. The present study examines the effects of household chemical products on teeth. A total of eight chemicals were utilized for this experiment. The corrosive chemical categories include: hydrochloric acid, sulfuric acid, phosphoric acid, and sodium hydroxide. Two products with each chemical were used, each representing varying concentrations of the corrosive product. Two human teeth were allocated for emergence in the chemical throughout a 24 h period of exposure. Results demonstrate hydrochloric acid as the most detrimental chemical to the dental samples. Sulfuric acid enacted minimal alterations to the teeth, although some etching and discoloration were noticeable. Phosphoric acid resulted in variable changes of the organic and inorganic contents of teeth. Lastly, exposure of sodium hydroxide resulted in little to no change. As hypothesized, distinct effects are obs...

A rapid fusion method was tested on concrete and brick samples. Actinides were determined rapidly using the fusion plus extraction chromatography and alpha spectrometry. Stacked TEVA, TRU and DGA rein cartridges were used with rapid flow rates. High chemical yields, effective removal of interferences and very good results were obtained.

The conversion of alicyclic and aliphatic carbonyl compounds as well as aromatic aldehydes into the corresponding oximes (up to quantitative yields) was achieved by simply grinding these reactants, hydroxylamine hydrochloride and sodium hydroxide without solvent. However, this procedure was unsuccessful in the case of aromatic ketones. In this case it was necessary to add silica gel as a catalyst.

Spherical water microtraps were prepared via a two steps process, which comprises the preparation of crosslinked poly(methacrylic acid) spheres by distillation-precipitation polymerization and the subsequent conversion of carboxylic groups to the corresponding sodium salts by treatment with aqueous sodium hydroxide solution. The influence of the cross-linker amount was investigated in order to achieve greater water absorption and a reversibility of the initial spheres after drying the formed hydrogel or washing with an excess of organic solvent. We achieved the highest water absorbency of about 70 times their weight occurring rapidly and unlimited times reversible after going through repeatable cycles of absorption and drying. This new material, called microtraps, was developed for its incorporation into multilayer anticorrosive coatings to prevent contact of water with metallic substrates.

This study is to improve the digestion pattern of miniprepped plasmid analyzed on gel. Frequently, some ambiguous DNA bands, which are suspected to be denatured DNA molecules, appear during electrophoresis of enzyme digested miniprepped plasmids. By employing Southern hybridization of two identical gels, one had been treated with denaruration-neutralization step and another without such treatment, we confirmed that many of these ambiguous DNA bands were singlestranded (SS) DNA molecules.

Silica nanoparticles have been prepared through dissolution-precipitation process from rice straw ash (RSA) for different electronic applications. The dissolution of silica from RSA was carried out using alkali leaching process by sodium hydroxide. The precipitation of silica from the produced sodium silicate solution was carried out using sulphuric acid at pH 7. The factors affecting the precipitation process of the sodium silicate solution of dissociated RSA; such as; sodium silicate concentration, sulfuric acid concentration and addition of anionic surfactant (sodium dodecyl sulfate, SDS) on the particle size of the precipitated silica were studied. X-ray diffraction (XRD), X-ray fluorescence (XRF), specific surface area S BET and transmission electron microscope (TEM) have been used for the characterization of the produced nano-silica. The results showed that the optimum conditions of the dissolution efficiency of the silica of about 99% was achieved at 100 • C for 4 h, and NaOH/SiO 2 molar ratio three. The particle size of the precipitated silica gel was decreased with increasing Na 2 SiO 3 and SDS concentrations, while H 2 SO 4 concentration had insignificant effect. Particle size of about 16 nm can be achieved at 30% Na 2 SiO 3 , 4% H 2 SO 4 and 200 ppm SDS. The produced silica had 99.93% purity, amorphous and nanosphere particles with narrow size distribution. The produced silica can be used in many applications especially for chemical mechanical polishing (CMP) slurries for semiconductors industries.

Background and Objectives  Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative diseases caused by aberrantly folded cellular proteins (PrPSc; prions) that are generally resistant to conventional pathogen-inactivation techniques. To ensure effective decontamination and inactivation of prions that could be present in source material, we investigated critical factors that influence prion inactivation by NaOH.Materials and Methods  A decrease in prion infectivity correlates with the disappearance of the protease-resistant core of PrPSc (PrPRES) observed in biochemical assays. To model prion inactivation, hamster scrapie (strain 263K) brain homogenate (SBH) was incubated for specific periods of time in 0·1 m NaOH at 4 or 18 °C, with or without detergent. Neutralized samples were subjected to limited digestion with proteinase K (PK) and then analysed using an endpoint dilution western blot assay and antibody 3F4. Structural changes in prions exposed to NaOH were examined using differential immunoprecipitation.Results  Treatment of SBH with 0·1 m NaOH for 15 min, in the absence of detergent, at 4 and 18 °C caused a reduction in the PrPRES signal of 3·5 and 4·0 log10 units, respectively, with some residual signal remaining. The presence of the detergent sarkosyl during a 60-min incubation in NaOH further enhanced PrPRES reduction to ≥ 4·5 log10 units (i.e. below the limit of detection). NaOH treatment induced conformational changes in PrP that resulted in the exposure of a hidden epitope and enabled prion immunoprecipitation by antibody 3F4.Conclusions  The use of NaOH can effectively reduce prion levels in an in vitro inactivation assay. After pretreatment of SBH with detergent, NaOH completely eliminates the PrPRES signal. Detergent may liberate lipid membrane-protected PrPSc to improve access to NaOH, which can then inactivate PrPSc by altering its structure. In cases of unidentified exposure to PrPSc during manufacturing, sanitizing procedures combining the use of detergent and NaOH may help to ensure minimal levels of contamination carryover in products.

Phosphoric acid (H3PO4) and sodium hydroxide (NaOH) treated rice husks, followed by carbonization in a flowing nitrogen were used to study the adsorption of malachite green (MG) in aqueous solution. The effect of adsorption on contact time, concentration of MG and adsorbent dosage of the samples treated or carbonized at different temperatures were investigated. The results reveal that the optimum carbonization temperature is 500 °C in order to obtain adsorption capacity that is comparable to the commercial activated carbon for the husks treated by H3PO4. It is interesting to note that MG adsorbed preferably on carbon-rich than on silica rich-sites. It is found that the behaviour of H3PO4 treated absorbent followed both the Langmuir and Freundlich models while NaOH treated best fitted to only the Langmuir model.

The simultaneous determination of several odorous trichlorobromophenols in water has been carried out by an in-sample derivatization headspace solid-phase microextraction method (HS-SPME).The analytical procedure involved their derivatization to methyl ethers with dimethyl sulfate/NaOH and further HS-SPME and gas chromatography-mass spectrometry (GC/MS) determination. Parameters affecting both the derivatization efficiency and headspace SPME procedures, such as the selection of the SPME fiber coating, derivatization-extraction time and temperature, were studied. The commercially available polydimethylsiloxane (PDMS) 100 μm and Carboxen-polydimethylsiloxane-divinylbenzene (CAR-PDMS-DVB) fibers appeared to be the most suitable for the simultaneous determination of these compounds. The precision of the HS-SPME/GC/MS method gave good relative standard deviations (RSDs) runto-run between 9% and 19% for most of them, except for 2,5-diCl-6-Br-phenol, 2,6-diCl-3-Br-phenol and-2,3,6-triBrphenol (22%, 25% and 23%, respectively). The method was linear over two orders of magnitude, and detection limits were compound dependent but ranged from 0.22 ng/l to 0.95 ng/l. The results obtained for water samples using the proposed SPME procedure were compared with those found with the EPA 625 method, and good agreement was achieved. Therefore, the in-sample derivatization HS-SPME/GC/MS procedure here proposed is a suitable method for the simultaneous determination of odorous trichlorobromophenols in water.

With advances in the development of DNA vaccines and gene therapy, there is a growing need for plasmid DNA with high quality for fundamental research and clinical trials. In this report, a scalable automated process for large-scale preparation of plasmid is described. This process is based on alkaline lysis and can be easily scaled up to meet demands for larger quantities. In the process, harvested bacteria are passed through two mixing chambers at controlled speeds to affect lysis and control alkalinity. The resulting solution is passed through a series of filters to remove contaminants, and ethanol precipitated. System parameters are examined to maximize the quantity and quality of the prepared plasmid. Using this procedure, plasmid can be extracted and purified from 1 l of Escherichia coli cultures at an OD600 nm of 50 in less than 45 min. The plasmid yields are approximately 90 mg/l culture.

In this research, the variations produced on the mechanical, morphological and thermal properties and on the melt index (MI) of a composite of polypropylene and wood¯our (WF) by the modi®cation of the ®ller were studied. The ®ller was treated with sodium hydroxide at dierent immersion times and with vinil-tris-(2-metoxietoxi)-silane. Polypropylenes functionalized with maleic anhydride (maleated polypropylene, MAPP) were also used as compatibilizers. All the treatments showed the same tendency to slightly increase tensile modulus and tensile strength of the composites, but they did not aect their MFI. Morphological studies showed that the MAPP and silane improve the polymer±WF adhesion and the dispersion of the particles, while the alkaline treatment only improves the dispersion. The silane-modi®ed samples and the use of MAPP produced samples with lower water absorption than those of untreated WF composites. The addition of the ®ller and the treatments carried out on it caused an increase in the crystallization temperature. Ó

Total and surface charge of unbleached and bleached softwood kraft pulps of different levels of freeness were determined using three different techniques-potentiometric titrations, conductometric titrations (with NaOH and NaHCO 3 separately) and polyelectrolyte titrations using a particle charge detector (PCD). Each method gave different charge values but the relative levels were similar for each pulp. The surface charge as determined by titration with poly-DADMAC was highly dependent on the degree of beating but the total fibre charge as given by potentiometric titration or conductometric titration with NaOH remained constant after beating. Conductometric titration with sodium hydroxide gave a slightly higher value for total charge than the potentiometric titration. Conductometric titrations with 0.05 M NaOH gave higher values of pulp charge than similar titrations with 0.05 M NaHCO 3 .

The effect of itaconic (IA) and fumaric (FA) acids, in the emulsion copolymerization of methyl methacrylate (MMA) with n-butyl acrylate (BA) is presented in this work. The effect of functional monomers on the overall conversion, on the colloidal properties of the latexes as well as on the distribution of the carboxylic groups (buried, particle surface and serum) was examined. The effect of the pH on the partitioning of IA and FA on the copolymerizations was also examined in order to better understand the role of these functional monomers. The carboxylic groups present in the cleaned latexes were analyzed using conductimetry and manual titration with a solution of sodium hydroxide in methanol. The results of these analyses showed that it was possible to determine the distribution profile of the carboxylic groups in the latexes (buried, particle surface and serum). It was demonstrated that IA and FA were distributed differently throughout the three phases of the emulsion, with these differences depending on the solubility of the corresponding monomer.

To investigate the role of major non-protein and protein sulfhydryls and disulfides in chemically induced gastric hemorrhagic mucosal lesions (HML) and the mechanism of gastroprotective effect of sucralfate. Rats were given 1 mL of 75% ethanol, 25% NaCl, 0.6 mol/L HCl, 0.2 mol/L NaOH or 1% ammonia solutions intragastrically (i.g.) and sacrificed 1, 3, 6 or 12 min later. Total (reduced and oxidized) glutathione (GSH + GSSG), glutathione disulfide (GSSG), protein free sulfhydryls (PSH), protein-glutathione mixed disulfides (PSSG) and protein cystine disulfides (PSSP) were measured in gastric mucosa and liver. Reduced glutathione (GSH) was depleted in the gastric mucosa after ethanol, HCl or NaCl exposure, while oxidized glutathione (GSSG) concentrations increased, except by HCl and NaOH exposure. Decreased levels of PSH after exposure to ethanol were observed, NaCl or NaOH while the total protein disulfides were increased. Ratios of reduced to oxidized glutathione or sulfhydrils to di...

In France, fatty residues considered as ''non-ultimate'' waste will not be accepted in landfill from 2002, in accordance with French legislation. Anaerobic digestion appears as an alternative process to mobilize and profitably use such fermentable waste. In this work, the effect of an alkaline pretreatment on the degradation of hexane extractible matter (HEM) and the production of volatile fatty acids (VFAs) was compared in reactors working at pH 6.5 and 8.5. The results obtained showed that 40% (AE0.1) of HEM were degraded at pH 8.5 versus 10% (AE0.3) at pH 6.5, regardless of the alkali agent used to saponify the greasy wastes. The highest performances of VFA production (8.45% AE 0.3) were obtained at pH 8.5 with greases saponified by potassium hydroxide, compared to results (4.25% AE 0.1) with greasy waste saponified by sodium hydroxide. This difference in VFA production might be attributable to biotoxic molecules generated during the saponification of greases by soda, limiting consequently the VFA production process.

Paracetamol IP traditionally considered as a NSAID, is an
effective analgesic and antipyretic drug available as over the
counter without prescription. Paracetamol IP is used widely in all
age groups and it has intensely bitter taste which makes it difficult
to administer in children. The current study is an attempt to
develop transdermal patches of Paracetamol IP for paediatric
patients by solvent evaporation method (with slight modifications)
using a hydrophilic polymer, Na CMC in combination with
polyvinyl pyrrolidone and glycerin as plasticizer. To improve the
effective permeation of Paracetamol IP through skin, permeation
enhancers such as 5% of oleic acid, menthol and ethanol are
incorporated. All the developed transdermal patches showed
desired properties of an ideal TDDS and followed ideal zero order
kinetics. Formulation containing 5% menthol as permeation
enhancer showed higher release rates.

We present the controlled solution-phase synthesis of several sheet-or rod-like bismuth oxides, BiOCl, Bi 12 O 17 Cl 2 , a-Bi 2 O 3 and (BiO) 2 CO 3 , by adjusting growth parameters such as reaction temperature, mole ratios of reactants, and the base used. BiOCl, Bi 12 O 17 Cl 2 , and a-Bi 2 O 3 could be prepared from BiCl 3 and NaOH, whereas (BiO) 2 CO 3 was prepared from BiCl 3 and urea. BiOCl and Bi 12 O 17 Cl 2 could also be prepared from BiCl 3 and ammonia. The a-Bi 2 O 3 sample exhibited strong emission at room temperature.

Solubility measurements of Au in dilute to concentrated aqueous NaOH solutions at 25°C have been carried out. The data were fitted to the general half reaction Au(c) + 2 HZ0 * Au02H:1E + nH+ + ein order to identify the stoichiometry and stability of the hydrolyzed species formed. The monohydroxide, AuOH( H20)', is found to be the most stable species up to pH -12. The equilibrium constant for the formation of this species (i.e., n = 1) is log K, = -22.57 f 0.44. Consideration of competitive complexation of Au by a number of inorganic ligands which are encountered in natural waters indicates that AuOH( HzO)' is the most stable inorganic Au species over a wide range of Eh, pH, and ligand activities. The only inorganic ligands which may occur in natural waters at concentrations high enough to stabilize Au(I) include HS under reducing conditions, SZO:-under alkaline oxidizing conditions, Cl-in very acidic, oxidizing brines, and possibly CN-locally, in environments where there is biogenic and/or anthropogenic production of cyanide. Calculated equilibrium pe-pH diagrams for Cl-and ZS activities typical of both fresh and seawater show that AuOH( H20)' is probably the dominant dissolved Au species in these environments, with the exception of anoxic ocean and lake waters.

A very sensitive analytical method is proposed for the determination of lithium based on the reaction of Li + ion wiht 1,4-dihydroxyanthraquinone (Quinizarin). In dimethylsulfoxide medium (90%) and in the presence of sodium hydroxide and sodium carbonate, a bluish-violet color (2ma x = 601 nm) develops and is stable over a period of 30 min to 2.5 h. The NaOH and Quinizarin concentrations were optimized simultaneously using the response surface methodology from sequential experimental Doehlert designs. Beer's law is obeyed in the concentration range 14-250 ppb Li + in aqueous and serum matrices, and the errors (RSD) in the determination of 100 ppb Li ÷ are 4.0% and 3.9°/,, respectively. The proposed procedure was satisfactorily applied to the determination of lithium in drugs and human serum (no deproteinization is required). substituents -OH in one ring and -COOH, -PO(OH)2 or -AsO(OH)2 in the second ring have been used as complexing agents of Li ÷ (Thoron, Quinazolinazo, Nitroantranylazo, Phosphonazo R, Arsenazo III) in photometric determinations [3]. Among these, Thoron (o-(2-hydroxy-3, 6-disulfo-1 -naphthylazo) benzenearsonic acid) has been the most used. Proposed by Kuznetsov [4], it gives, together with Li ÷ ion, an orange color in a strong basic medium. The spectrophotometric method using this reagent, developed by Thomason [5], has been used for the determination of lithium in high-purity beryllium and beryllium oxide [6], sea water [7], mollusc shells [8] and blood serum .

As revealed by NMR spectroscopy (after ultrasonic degradation) and HPLC (after total hydrolysis) an arabinoxylan (AX) containing 74.8% Xylp and 23.2% Araf was isolated from Ispaghula (Plantago ovata) by soaking the seed husk with water, extraction with aqueous sodium hydroxide and coagulation with acetic acid. The AX with a molar mass of 364,470 g/mol shows high swelling ability in water. The carboxymethylation of AX was carried out heterogeneously with sodium monochloroacetate in the presence of aqueous sodium hydroxide. The reaction parameters were varied in terms of slurry medium, molar ratio, temperature, time, and sodium hydroxide concentration. For comparative studies, carboxymethylation of arabinan was carried out. In order to determine the total degree of substitution (DS) and mole fractions of the repeating units of carboxymethyl arabinoxylan (CMAX) and of carboxymethyl arabinan, HPLC and 1 H NMR spectroscopic investigations after total hydrolysis were carried out. DS values for CMAX as high as 1.81 were achieved. CMAX is water soluble starting at DS of 0.33.