Amino acid pattern of the Egyptian apricot fruits (Hamawy)

Apricot fruits were subjected to acid hydrolysis and the amino acids were separated and quantitatively determined by paper chromatography. The analysis revealed the presence of 19 amino acids, predominantly glutamic acid, aspartic acid, histidine, arginine and tyrosine. The results also demonstrated that the concentrations of cystine, methionine and hydroxyproline were relatively small.     

Amino Acid Pattern and Nutritional Evaluation of Precipitates from Aqueous By-Products of Starch Industry

Precipitates containing 43% protein were obtained from corn steep liquor by pH adjustments in the range of 6 to 7. From the sorter liquor of the starch manufacture materials containing up to 65% protein were produced by adjusting the pH-value around 5. Chemical analysis showed that at least 19 amino acids were present. The essential amino acids leucine, iso-leucine, cystine, methionine, tyrosine, phenylalanine, lysine, threonine and valine were present in variable amounts. The economic application of pH-adjustment methods for production of proteins and their use for human nutrition is discussed.     

Amino Acid Patterns of Different Brands of Corn Steep Liquor

The free amino acids as well as the total amino acid content of Russian corn steep liquor (CSL), French CSL, British CSL, Italian CSL, German dried version of CSL, and Egyptian CSL were identified. The free amino acids and those obtained after the acid hydrolysis in each sample were almost the same. Alanine was the predominant free amino acid found. The major amino acids were arginine, aspartic acid, histidine, glutamic acid, glycine, leucine, lysine, serine and valine with the exception of Italian CSL and German dried CSL, while phenylalanine, methionine, tyrosine, proline as well as cystine were present in lesser amounts. The relation between the amino acid constituents of the different brands of CSL and their penicillin activity were discussed.     

A DLL-biased, 14-bit DS analog-to-digital converter for GSM/GPRS/EDGE handsets

A 14-bit analog-to-digital converter (ADC) design for GSM/GPRS/EDGE handsets is implemented in 0.25 /spl mu/m CMOS. The measured SNR/SNDR/DR is 85.2/84.1/88 dB respectively. The modulator and the clock generator consume 1.05 mA from 2.7 V supply. A delay-locked-loop (DLL)-based bias scheme is implemented to guarantee that amplifier slewing takes a fixed percentage of the clock cycle over process corners, temperature, and clock frequency. The proposed biasing scheme is shown to minimize settling error variations and contain design margins.     

A Multigigahertz Multimodulus Frequency Divider in 90-nm CMOS

This brief presents a multimodulus frequency divider with division ratio between 64 and 127 fabricated in 90-nm CMOS. By using a load-switching technique, high operating frequency, and low power static divider was achieved. The divider consists of six 2/3 divider stages. The maximum operating frequency is 4.7 GHz with current consumption 2.3 mA at low voltage supply 1.2 V and rms cycle-to-cycle jitter lower than 1 ps     

GEOCHEMICAL CHARACTERIZATION OF A BIODEGRADED CRUDE OIL, ASSRAN FIELD, CENTRAL GULF OF SUEZ

A crude oil sample from the Assran field in the Central Gulf of Suez (Egypt) was analysed geochemically and characterized in terms of a variety of source and maturity dependent biomarkers. Biodegradation was indicated by increasing concentration ratios of Pr/n-C₁₇ and Ph/n-C₁₈. However, biodegradation was only slight as GC-MS analyses of the saturate and aromatic fractions showed that hopanes, steranes, aromatic steroids and polycyclic aromatic compounds including sulphur heterocycles remained intact. The sterane and hopane distributions showed a predominance of C₂₇ steranes, a low diasterane index, an abundance of gammacerane, a high homohopane index and an oleanane index < 0.2. The results indicate that the Assran-10 crude oil was derived from a marine carbonate source deposited in a highly reducing saline environment with a high bacterial contribution, consistent with the Upper Cretaceous Brown Limestone or Lower Eocene Thebes Formation containing Type IIS kerogen. Maturity parameters based on changes in the stereochemistry at chirality centres in hopane and sterane nuclei, such as C₃₀βα/(βα+αβ) and C₃₁ 22S/(22S+22R) hopanes and C₂₉ββ/(ββ+αα) and C₂₉ 20S/(20S+20R) steranes, together with triaromatic sterane cracking ratios, indicate that the oil sample was marginally mature. The results also suggest that biodegradation is probably due to sulphate-reducing anaerobic bacteria.     

Biochemical studies for utilisation of corn steep liquor in production of proteins

Chemical analysis of corn steep liquor, produced from wet milling of corn grains, revealed the presence of 13% total soluble solids, 5.2% proteins and 2.5% ninhydrin reacting compounds. A cheap method, depending upon pH adjustment, was devised to obtain large amounts of precipitates with protein content up to 43%. The supernatants resulting after separation of the precipitates were tested as a growth medium for production of fodder yeast Candida utilis. The supernatants supported good growth of the yeast without addition of extraneous sources of nutrients or vitamins. Depending on the supernatant yields ranging between 15 to 29 g of dry yeast per litre were obtained per litre with protein content 98 to 55%. The industrial application of these findings is discussed.     

A 900-MHz dual-conversion low-IF GSM receiver in 0.35-μm CMOS

A low-power fully integrated GSM receiver is developed in 0.35-μm CMOS. This receiver uses dual conversion with a low IF of 140 kHz. This arrangement lessens the impact of the flicker noise. The first IF of 190 MHz best tolerates blocking signals. The receiver includes all of the circuits for analog channel selection, image rejection, and more than 100-dB controllable gain. The receiver alone consumes 22 mA from a 2.5-V supply, to give a noise figure of 5 dB, and input IP3 of -16 dBm. A single frequency synthesizer generates both LO frequencies. The integrated VCO with on-chip resonator and buffers consume another 8 mA, and meets GSM phase-noise specifications     

Immobilization of Co(Ⅱ) Ions in Cement Pastes and Their Effects on the Hydration Characteristics

The immobilization of Co(Ⅱ) in various cement matrices was investigated by using the solidification/stabilization(S/S) technique.The different cement pastes used in this study were ordinary Portland cement in absence and presence of water reducing-and water repelling-admixtures as well as blended cement with kaolin.Two ratios of Co(Ⅱ) were used(0.5% and 1.0% by weight of the solid binder).The hydration characteristics of the used cement pastes were tested via the determination of the combined water content,phase composition and compressive strength at different time intervals up to 180 d.The degree of immobilization of the added heavy metal ions was evaluated by determining the leached ion concentration after time intervals extended up to 180 d.The leachability experiments were carried out by using two modes:the static and the semi-dynamic leaching processes.It was noticed that the concentration of the leached Co2+ ions in the static mode of leachability was lower than the solubility of its hydroxide in all the investigated cement pastes.     

Some properties of Streptococcus faecalis subsp. liquefaciens isolated from cheese with special reference to production of bitterness

Streptococcus faecalis subsp. liquefaciens was examined for proteolysis and development of bitterness in sterile buffaloes' skim milk with and without some additives. Cell population and the pH of milk were the most important factors in the breakdown of casein and development of bitterness. Sodium chloride level, altering the final concentration of bacteria in milk, had a direct role in the production of bitter peptides. Calcium ions up to 5 mM did not affect proteolysis whereas higher concentrations were inhibitory. Electrophoretic analysis of proteose-peptone formed in sterile skim milk with and without NaCl revealed the presence of 3 peptides, 2 of which were probably associated with bitterness. S. faecalis subsp. liquefaciens produced acidity slowly, but was the most acid producer (1.25% after 72 h) of the streptococci. However, milk coagulated enzymatically and the curd shrinkage was related to salt-dependent acidity. Strains of the organism coagulated fresh citrated human plasma within 21 h at 30 degrees C, but without any visible fibrinolysis. The strains also were all alpha-haemolytic with occasionally a very few beta-haemolytic variants on sheep blood agar. On human blood agar, a weak alpha-reaction was given.