The identification of the fatty acids of the fat from a North American black bear

Summary A study has been made of the identification of the fatty acids of the fat from a North American black bear. The methyl esters of the fatty acids from the fat were prepared and fractionated through a Stedman Column. Myristie, palmitic, stearic, oleic, palmitoleic, and linoleic acids were identified by the melting points of the p-bromophenacyl ester of the saturated acids and the hydroxy and bromine addition compounds of the unsaturated acids. Published with the approval of the Director of the Michigan Agricultural Experimental Station as Journal article No. 970 (new series).     

A CMOS ADSL codec for central office applications

A CMOS central office codec that supports Full Rate and G.Lite asymmetric digital subscriber line (ADSL) transmission is described. The transmit channel consists of application-dependent digital filters, a 14-bit, 8.832-MSample/s current steering DAC, a 1.104-MHz analog filter, and a programmable attenuator. Due to extensive on-chip digital signal processing, the codec complies with the ADSL transmit power spectral density standards without external filtering. The receive channel contains -17.5 to 33.5 dB of programmable gain staggered strategically across three stages, a 138-kHz analog low-pass filter, a 14-bit, 2.208-MSample/s pipeline ADC, and a digital 138-kHz low-pass filter. The receive channel has a wide input range that can accommodate large line voltages present at the line hybrid circuit. The IC occupies 55.2 mm² and dissipates 450 mW from a 3.3-V supply     

Stable and noniterative bidirectional beam propagation method

We present a family of bidirectional beam propagation methods based on the application of Pade approximants to the square-root expressions appearing in the transition operator. We show that the numerical instability associated with the use of real Pade primes can be removed by using branch-cut rotation of the square-root operator     

Melt grafting of glycidyl methacrylate onto polypropylene and reactive compatibilization of rubber toughened polypropylene

Free radical melt grafting of glycidyl methacrylate (GMA) onto polypropylene (PP) was studied. The extent of GMA grafting and the molecular weight of the functionalized PP copolymers were controlled by carefully manipulating various reaction factors, such as monomer concentration, initiator concentration, reaction temperature, and molecular weight of the starting PP homopolymer. The use of a second monomer, styrene, in the grafting process helped to increase GMA grafting further and reduce chain scission. The GMA modified PP copolymer was found to be able to reactively compatibilize PP/acrylonitrile-co-butadiene-co-acrylic acid rubber (NBR) blends. Up to an eight-fold increase in the impact energy of the PP/NBR blend was obtained. The compatibilizing capacities of the reactive copolymers, in terms of impact energy improvement of the PP/NBR blend, were found not to be exclusively dependent on the total concentration of reactive functionalities in the matrix of the blend. The characteristics of the reactive copolymers, i.e., the extent of functionalization and the molecular weight, were found to have significant influences on the compatibilizing capacity. A large amount of moderately functionalized copolymer offers better compatibilization performance than a small amount of highly functionalized copolymer. A significant drop in impact energy was observed with declining molecular weight of the copolymer.     

采用MEMS技术高选择性、电子调谐式低温滤波器

描述了一种使用HTS/AuMEMS 开关电容器阵的低插损电子调谐式滤波器。同步将每个谐振器的电容值以相同变化量变化,两极滤波器就得到调谐。单极谐振器在3500～5000之间的K 系数得到了证明。在77K 平均Q 值为7000 时的总调谐范围大约为25%。     

BRET-Based Biosensors to Measure Agonist Efficacies in Histamine H1 Receptor-Mediated G Protein Activation,Signaling and Interactions with GRKs and β-Arrestins

The histamine H₁ receptor (H₁R) is a G protein-coupled receptor (GPCR) and plays a key role in allergic reactions upon activation by histamine which is locally released from mast cells and basophils. Consequently, H₁R is a well-established therapeutic target for antihistamines that relieve allergy symptoms. H₁R signals via heterotrimeric G_q proteins and is phosphorylated by GPCR kinase (GRK) subtypes 2, 5, and 6, consequently facilitating the subsequent recruitment of β-arrestin1 and/or 2. Stimulation of a GPCR with structurally different agonists can result in preferential engagement of one or more of these intracellular signaling molecules. To evaluate this so-called biased agonism for H₁R, bioluminescence resonance energy transfer (BRET)-based biosensors were applied to measure H₁R signaling through heterotrimeric G_q proteins, second messengers (inositol 1,4,5-triphosphate and Ca²⁺), and receptor-protein interactions (GRKs and β-arrestins) in response to histamine, 2-phenylhistamines, and histaprodifens in a similar cellular background. Although differences in efficacy were observed for these agonists between some functional readouts as compared to reference agonist histamine, subsequent data analysis using an operational model of agonism revealed only signaling bias of the agonist Br-phHA-HA in recruiting β-arrestin2 to H₁R over G_q biosensor activation.     

Novel waterborne hyperbranched acrylated-maleinized alkyd resins

Different waterborne hyperbranched acrylated-maleinized alkyd resins (HBRAAM) were synthesized by modifying a hyperbranched alkyd resin (HBRA) with three different butylmethacrylate–maleic anhydride copolymers (BMA–MA) in the presence of p-toluenesulfonic acid (PTSA). The HBRAAM resins were characterized by using infrared analysis, iodine value, hydroxyl value, vapor pressure osmometry (VPO), dynamic light scattering (DLS), acid value, rheological analysis, differential scanning calorimetry, adhesion, flexibility, drying time, gloss, hardness and chemical resistance to solvents. The iodine value and hydroxyl value decreased with the amount of BMA–MA copolymer employed in the synthesis. Infrared analysis, VPO, and hydroxyl values allowed us to conclude that the reaction between HBRA resins and BMA–MA copolymers occurred. The viscosity of the HBRAAM resins was between 50.5 and 468 Pa s. All HBRAAM resins presented good properties of adhesion, flexibility, drying time, gloss, hardness and chemical resistance.     

Fatness and fat distribution by social stratum in Venezuelan youths

Adiposity and distribution of body fat are important issues in the prediction of degenerative diseases. Measurements of weight, height, circumferences of thigh, waist and hip; triceps, biceps, subscapular and suprailiac skinfolds; body mass index (BMI), centripetal index (CI), waist/hip (WHR), waist/thigh (WTR) ratios and sigma skinfold thickness (sigma SK) were performed in 836 youths (373 males, 463 females) aged 11, 13 and 15 years. Analysis method included Student t test, ANOVA, Principal Component Analysis and simple linear regression model, with sigma skinfold thickness as independent variable. The sample was divided in two groups (A and B) according with Graffar-Méndez Castellano methodology. Sexual dimorphism in adiposity and differences in body fat distribution were found with a tendency towards peripherical distribution for girls and centripetal for boys. Group A (higher stratum) showed higher values of skinfolds in both trunk and extremities, and a more peripherical distribution than his peers from group B. First component from extremity/trunk and second component from upper/inferior trunk distribution explained 40.2% and 32.7% of the variability respectively. CI and WHR appear dependent from BMI, WHR showed independence from BMI, although significant differences was found by social stratum, reflecting differences in fat topography in boys and girls from group B. These results confirm more adiposity in group A and a tendency towards central distribution in group B. Studies of body fat distribution during these age should include waist/thigh ratio.     

Lipase-catalyzed interesterification reaction between menhaden oil and the ethyl ester of CLA: Uniresponse kinetics

The kinetics of the interesterification reaction between menhaden oil and the ethyl ester of CLA (CLAEE) in the presence of an immobilized lipase from Rhizomucor miehei was investigated. A 2³ factorial design with a central point was used to define the experimental region. The factors considered were the molar ratio of reactants, the enzyme loading, and the temperature. Optimal results were obtained when the reaction was carried out at 55°C with an enzyme loading of 0.65 g per 12 g mixture and a mole ratio of CLAEE to menhaden oil equal to 0.13. A uniresponse kinetic model of the Michaelis-Menten type was developed to characterize the rate of consumption of CLAEE and the rate of release of FA ethyl esters from menhaden oil. The best fit of the data with a uniresponse model was obtained using a form based on reversible reactions and inhibition by the ethyl esters of the FA residues released by the reaction.