Characterization of Pearl Millet Nonstarchy Polysaccharides

Water-soluble nonstarchy polysaccharides (WSNP) and water-insoluble nonstarchy polysaccharides (WINP) of pearl millet (Pennisetum typhoides) were isolated, purified and characterized for carbohydrate composition. Gas-liquid chromatographic analysis of the derived alditol acetates obtained from hydrolyzed WSNP, WINP and their respective DEAE-cellulose fractions revealed similarities in carbohydrate content, but marked differences in distribution pattern. Rhamnose, ribose, L-arabinose, xylose, mannose, galactose, and glucose were detected. Sepharose 4B chromatography confirmed arabinoxylan as the predominant polysaccharide, with significant amounts of arabinogalactan, and glucan noticeable in some fractions. UV spectral analysis and thin-layer chromatography showed ferulic acid as the major phenolic compound, in addition to caffeic acid and two other unidentified phenolic acids.     

Empirical Observations and Thermodynamical Considerations on Water-Binding by Whey Proteins in Food Products

Basic protein knowledge is used to explain protein functionality in food products. Empirical observations on the water-binding capacity of whey protein concentrate and gelatin during cooling in set yoghurt and during sterilization of meat products are discussed in terms of effects of temperature on the structure and thermodynamic behavior of their main protein isolates: α-Lactalbumin and tropocollagen, respectively. It appears that the water-binding of proteins is governed by their thermally induced folding behavior. In particular, the greater tendency of whey proteins to fold at low temperature due to hydrophobic effects, and to remain dispersed at high temperatures as a result of disorder effects, keeps these proteins from water-retention in a network structure during cooling and sterilization.     

MEASURING the MECHANICAL PROPERTIES of APPLE TISSUE USING MODAL ANALYSIS

Along with the grade of intactness, fruit firmness is an important factor for the quality criteria on which the consumers acceptance for apples is based. Two methods for measuring the fruit firmness (a destructive one and a nondestructive one) are compared. the nondestructive method uses modal analysis to define the lower vibration modes. This enables the use of the 3-media elastic sphere model developed by Cooke and Rand (1973) to calculate the dynamic elastic moduli of the whole apples. the destructive method determines the dynamic elastic moduli of cylindrical samples of apple tissue. This method is based on the vibration characteristics of a mass-spring-damper system. This system consists of a cylindrical apple sample and a mass. Measuring the direct transfer function of this one-degree-of-freedom system results in values of its system parameters, from which the dynamic elastic moduli of the specimen can be calculated. The results of the two methods applied on Golden Delicious apples were compared, and the suitability of each model was evaluated.     

CONSTRAINED NON-LINEAR PROGRAMMING: A MINIMUM CROSS-ENTROPY ALGORITHM

The paper presents an information-theoretic algorithm for solving constrained non-linear programming problems based upon the principle of minimum cross-entropy and surrogate mathematical programming. It is an alternative to the earlier work by Templeman and Li [4-6] based on the maximum entropy principle and so far as the rate of convergence of the solution is concerned it is an improvement upon it, The merit of the present technique is illustrated with two numerical examples.     

Emergence of recombinant strains of Helicobacter pylori during human infection

Genetic recombination can be important evolutionarily in speeding the adaptation of organisms to new environments and in purging deleterious mutations. Here, we describe polymerase chain reaction (PCR), hybridization and DNA sequence-based evidence of six such exchanges between two strains of Helicobacter pylori during natural mixed infection of a patient in Lithuania. One parent strain contained the 37 kb long, virulence-associated cag pathogenicity island (PAI), and the other strain lacked this PAI. Most H. pylori from the patient had descended from the cag+ parent, but had become cag- during infection. This had resulted from transfer of DNA containing the 'empty site' allele from the cag- strain and homologous recombination, not from excision of the cag PAI without DNA transfer. Other cases of recombination involved genes for an outer membrane protein (omp5 and omp29; also called HP0227 and HP1342) and a putative phosphoenolpyruvate synthase (ppsA; HP0121). Replacement of a short patch of DNA sequence (36-124 bp) was also seen. As the chance of forming any given recombinant is small, the abundance of recombinants in this patient suggests selection for particular recombinant genotypes during years of chronic infection. We suggest that genetic exchange among unrelated H. pylori strains, as documented here, is important because of the diversity of this gastric pathogen and its human hosts. Certain H. pylori recombinants may grow better in a given host than either parent. The vigour of growth, in turn, could impact on the severity of disease that infection can elicit.     

Dopamine D2-receptor isoforms expressed in AtT20 cells inhibit Q-type high-voltage-activated Ca2+ channels via a membrane-delimited pathway

Dopamine D2 receptors both acutely and chronically inhibit high-voltage-activated Ca2+ channels (HVA-CCs). Two alternatively spliced isoforms, D2L (long) and D2S (short), are expressed at high levels in rat pituitary intermediate lobe melanotropes but are lacking in anterior lobe corticotropes. We stably transfected D2L and D2S into corticotrope-derived AtT20 cells. Both isoforms coupled to inhibition of Q-type calcium channels through pertussis toxin-sensitive G proteins. Thus, we have created a model system in which to study the kinetics of D2-receptor regulation of Ca2+ channels. Rapid inhibition of HVA-CCs was characterized using a novel fluorescence video imaging technique for the measurement of millisecond kinetic events. We measured the time elapsed (lag time) between the arrival of depolarizing isotonic 66 mM K+, sensed by fluorescence from included carboxy-X-rhodamine (CXR), and the beginning of increased intracellular Ca2+ levels (sensed by changes in indo 1 fluorescence ratio). The lag time averaged 350-550 ms, with no significant differences among cell types. Addition of the D2-agonist quinpirole (250 microM) to the K+/CXR solution significantly increased the lag times for D2-expressing cells but did not alter the lag time for AtT20 controls. The increased lag times for D2L- and D2S-transfected cells suggest that at least a fraction of the Ca2+ channels was inhibited within the initial 350-550 ms. As this inhibition time is too fast for a multistep second messenger pathway, we conclude that inhibition occurs via a membrane-delimited diffusion mechanism.     

A tabular method for finding 2-summable and mutually 2-summable pairs of minterms

The paper presents a table look-up method for testing threshold and isobaric functions by finding out the possible 2-summable and mutually 2-summable pairs of minterms respectively. The method provides ready visualization of such pairs with a much less computational labour than the methods suggested so far. It has been shown that there will be further reduction in computational labour if the test functions are made positive unate.     

Infective spondylodiscitis in patients on high‐flux hemodialysis and on‐line hemodiafiltration

Infective spondylodiscitis (ISD) is a rare but potentially devastating condition in hemodialysis (HD) patients. Reports are limited especially in patients receiving high‐flux HD and hemodiafiltration (HDF). In a retrospective analysis, 13 patients on our maintenance high‐flux HD/HDF program were identified as having has infective spondylodiscitis over a 10‐year period (1997–2006), an incidence of approximately 1 episode every 215 patient‐years. The incidence was around 3 times higher in patients dialyzing with tunnelled central venous catheters (TCVC) than in those with arteriovenous fistulae. Affected patients were elderly (mean age 70 years) and had multiple comorbidities. Access problems, particularly TCVC infection, were common in the months preceding it's onset. Tunnelled central venous catheter removal during these episodes did not necessarily prevent it. Diagnosis was based on a history of back pain, raised C‐reactive protein, positive blood cultures, and characteristic magnetic resonance findings. Many patients were apyrexial and had normal white cell counts. In our patients on high‐flux HD/hemodiafiltration, its incidence appears comparable to that in conventional HD settings. No patients had infection with waterborne organisms. Blood cultures were positive in 77%. Gram‐positive organisms predominated, particularly Staphylococcus aureus. The major route of infection was hematogenous, with the most likely source the venous access. All received antibiotics for 6 to 12 weeks or until death. Only 2 patients underwent surgical drainage. Mortality was high (46%) and predicted by the development of complications, and by pre‐existing cardiovascular comorbidity. Prevention, using strategies to reduce the prevalence of bacteremia, including limiting the use of TCVC, should be an overriding aim.     

SiC-ZrO2(3Y)-Al2O3纳米复相陶瓷的力学性能和显微结构

本文介绍用非均相沉淀方法制备的纳米SiC-ZrO2(3Y)-Al2O3复合粉体经放电等离子超快速烧结得到晶内型的纳米复相陶瓷,超快速烧结的升温速率为600℃/min,在烧结温度不保温,迅即在3 min内冷却至600°C以下. 力学性能研究结果表明,在1450℃超快速烧结得到的纳米复相陶瓷的抗弯强度高达1200MPa,断裂韧性K1c为5 MPa1/2. TEM像显示纳米SiC颗粒大多分布在Al2O3母体晶粒内,也有一些纳米SiC颗粒分布在ZrO2晶粒内. 断裂表面的SEM像表明,穿晶断裂是其主要的断裂模式,这是所制备的纳米复相陶瓷力学性能大幅提高的主要原因.     

New results in stability of a class of hereditary linear systems

Some basic connections between bounded-input, bounded-output stability and exponential asymptotic stability are presented for a class of linear time-varying hereditary systems. For that class of systems, controllability and observability are closely related to that of an equivalent linear system. This eases the analytical treatment of such properties which are then used to derive the stability results. The requirement of boundedness of inputs and outputs in the BIBO definition is modified by requesting that their ‘energy content’ over a fixed-length interval should be bounded independently of the position of the interval. For the class of hereditary linear systems studied, it is found that EAS and BIBO stability are equivalent under uniform complete controllability and observability.