Influence of pH on recombinant human growth hormone production by Pichia pastoris

BACKGROUND: Effect of pH on recombinant human growth hormone (rhGH) production by Pichia pastoris hGH‐Mut⁺ was investigated at pH = 4.2, 5.0, 5.5, and 6.0. RESULTS: The highest cell concentration was obtained at pH = 6.0 with 53 g L^?1, while the highest rhGH concentration was attained at pH = 5.0 as 0.27 g L^?1. Total protease secretion increased with increase in pH and with the cultivation time. Oxygen uptake rate increased with increasing pH up to pH = 6.0, having the maximum value, 37 mmol m^?3 s^?1, at pH = 5.5. K_La values were similar at all the conditions, having a maximum value of 0.14 s^?1 at pH = 5.0. Taking the final rhGH concentration into account, the most favourable pH was 5.0; where AOX1 expression level showed a similar trend to AOX activity profiles, having the highest value of 9.4 × 10¹⁰ copy mg^?1 CDW at t = 15 h; in parallel to AOX1 expression profile, hGH expression level increased until t = 15 h, with the highest value of 4.0 × 10¹⁰ copy mg^?1 CDW, where a sharp increase in rhGH concentration was obtained. The expression levels of pep4, prb1 and prc1 genes, responsible from the production of proteinase A, proteinase B and, carboxypeptidase Y, were parallel to each other. CONCLUSION: Since it was shown that pH is a crucial operating parameter in fermentation processes using P. pastoris, keeping pH constant at its determined optimum value, pH = 5.0, during the bioprocess is vital in terms of recombinant protein production. Copyright © 2010 Society of Chemical Industry     

Image enhancement via space-adaptive lifting scheme exploiting subband dependency

This paper proposes an image enhancement method based on space-adaptive, 2-D lifting scheme. In the space-adaptive update-first lifting scheme, the prediction stage is adapted to the signal structure point-by-point which results in a better signal representation and enhancement result. In this paper, a novel edge-sensitive adaptive prediction method is introduced in the 2-D lifting framework. The method adaptively chooses the best predictor among a set of predictors minimizing the prediction error. The proposed prediction method is sensitive to both even and odd indexed edge pixels in the 2-D lifting context. The bivariate shrinkage which assumes the dependence of the subband wavelet coefficients is used for subband image enhancement. As an objective quality measure, the peak signal-to-noise ratio test is applied to the results of the proposed image enhancement algorithm. Results of the proposed algorithm are compared with those of the VisuShrink, BayesShrink, and NorShrink. Experimental and objective quality test results prove the superior performance of the proposed image enhancement method.     

Evaluation of turbo and hydro‐generator torques due to electromechanical interaction

Abstract

The computer prediction of turbogenerator behaviour following fault or disturbance conditions has become an important feature in the assessment of machine system design, pre‐commissioning test appraisals, system operational procedures, machine monitoring strategy and post‐event damage diagnoses. In this paper computer methods are described to assess the comparative severity of various electrical faults and disturbances, the effect of specific operational practices together with the prediction of peak torsional transient behaviour. This paper is supported by realistic examples simulating the transient behaviour of a number of generational units.     

Survival of the fittest: Implications of self-reliance and coping for leaders and team performance.

Using a laboratory methodology, the authors sought to establish an association between self-reliance (based on attachment theory) and team performance and satisfaction. Three hypotheses (direct effect, mediator, and moderator) were tested. With a sample of 187 students, the authors compared leader self-reliance characteristics with group member self-reliance characteristics (group n?=?50) as predictors of group performance and satisfaction. Only group member counterdependence was predictive of decreased performance. Further, the authors examined the possible mediating and moderating effects of coping on the self-reliance–group effectiveness relationships. Coping did not mediate the relationship but did operate as a significant moderator in some instances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

On a multivariable extension of Jacobi matrix polynomials

The classical Jacobi matrix polynomials only for commutative matrices were first studied by Defez et al. [E. Defez, L. Jódar, A. Law. Jacobi matrix differential equation, polynomial solutions and their properties, Comput. Math. Appl. 48 (2004) 789–803]. The main aim of this paper is to construct a multivariable extension with the help of the classical Jacobi matrix polynomials (JMPs). Generating matrix functions and recurrence relations satisfied by these multivariable matrix polynomials are derived. Furthermore, general families of multilinear and multilateral generating matrix functions are obtained and their applications are presented.     

Social-contextual influences on expectancies for managing anger and sadness: The transition from middle childhood to adolescence.

This study examined the influence of emotion type (i.e., anger, sadness), audience type (i.e., mother, father, best friend), gender, and age on 140 5th-, 8th-, and 11th-grade adolescents' emotion management decisions, emotional self-efficacy, and outcome expectancies. Participants were read 8 vignettes and responded to 8 questions per vignette. Results indicated that 8th-grade adolescents reported regulating emotion most and expected the least interpersonal support from mothers. Children expressed greater self-efficacy and regulation of sadness than of anger. Boys reported dissembling emotion and expecting a negative interpersonal response to emotional behavior more than did girls. Children were more concerned with protecting feelings of friends than with protecting feelings of fathers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Psychological influences on surgical recovery: Perspectives from psychoneuroimmunology.

Greater fear or distress prior to surgery is associated with a slower and more complicated postoperative recovery. Although anxiety presumably interferes with recuperation through both behavioral and physiological mechanisms, the pathways have been unclear. Recent work in psychoneuroimmunology (PNI) has demonstrated that stress delays wound healing. In addition, a second line of research has illustrated the adverse effects of pain on endocrine and immune function. A biobehavioral model is described that is based on these and other data; it suggests a number of routes through which psychological and behavioral responses can influence surgery and postsurgical outcomes. Clinical and research implications are highlighted. (PsycINFO Database Record (c) 2010 APA, all rights reserved)