Studies on non-enzymic browning in orange juice using a model system based on freshly squeezed orange juice

An orange juice based model system was set up wherein variables such as the addition of glucose, lysine, sorbitol and L -ascorbic acid and changes in pH and storage temperature were introduced to study their effects on L -ascorbic acid degradation and on browning. The addition of glucose, lysine and sorbitol did not have a significant effect on L -ascorbic acid degradation, whereas added L -ascorbic acid acted solely as a reserve material. In terms of browning, a change in pH and storage at elevated temperature produced a synergistic effect in the development of brown colour which was enhanced by the introduction of additives. Based on the results obtained, L -ascorbic acid appears to be the precursor in the non-enzymic browning occurring in this type of sample due to the formation of reactive carbonyl compounds produced upon its degradation which tend to polymerise, or to react with nitrogenous compounds, to give brown pigments.     

Culturally sensitive psychotherapy for Puerto Rican children and adolescents: A program of treatment outcome research.

Recognition of cultural distance between Hispanic clients and non-Hispanic therapists has prompted efforts to introduce culture into therapy, but there is little evidence that such efforts influence treatment outcomes. This article evaluates treatment outcomes from a program of research on modeling therapy with Puerto Ricans, targeting anxiety symptoms, acting-out behavior, and self-concept problems. Evaluation of outcomes confirmed the impact of culturally sensitive modeling therapy on anxiety symptoms and other selected target behaviors, but negative treatment effects also were evident. Results suggest that new approaches to psychotherapy for special populations, such as Hispanic children and adolescents, should be buttressed by programmatic research oriented toward the comparative evaluation of treatment outcomes and should be attuned to therapeutic processes mediating between culture and outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electromigration testing of integrated circuit interconnections

The electromigration phenomenon has been one of the most intriguing physical problems in the semiconductor device reliability. The models to explain the phenomenon are here revised, together with the influence of materials and their microstructure. The various measuring techniques are described, including the design of special test patterns, and statistical data analysis is briefly reviewed.     

Uncertainty in biomass supply estimates: Lessons from a Yakama Nation case study

The increasing demand for bioenergy in the United States necessitates detailed case studies of cost and supply to assess its feasibility. We have developed supply curves based on six feedstocks in five counties surrounding the Yakama Nation in central Washington using spatially explicit estimates of supply and transportation cost. The supply curves were used to examine a base case supply for a bioenergy plant, to analyze the effects of land ownership, and examine the impacts of uncertainty in parameters used to determine cost and supply. The results show that existing industries produce the cheapest supply of feedstock as a byproduct of their operations, while supplies harvested specifically for bioenergy are considerably more expensive. Fragmented land ownerships lead to the necessity of cooperation between owners and highlight the importance of a strong anchor supply close to the plant. Lastly, uncertainty in supply and cost parameters leads to larger ranges in available biomass, leading to reluctant investment in large plants.     

The toxic effects of selected heavy metals on unadapted populations of Vorticella convallaria var similis

The presence of large amounts of heavy metals in sewages may cause severe disruption of the biological processes involved in sewage treatment, and thus a decline in the quality of the effluent produced. Unadapted populations of Vorticella convallaria var similis, a sessile peritrich protozoan found abundantly in healthy rivers, activated sludge, percolating filters and slow sand filters, were subjected to a range of concentrations of three common pollutant metals. It was found that these populations were killed by concentrations of, and above, 0.0005 mg/l. of the free metal ion of either lead or mercury. Colonies were also killed by concentrations of, and above, 0.075 mg/l. of the free metal ion of zinc. 12 hr 50% lethal doses were calculated, and for V. convallaria var similis were found to be 0.0036 mg/l. for lead, 0.005 mg/l. for mercury and 0.29 mg/l. for zinc.     

An entropic characterization of protein interaction networks and cellular robustness.

The structure of molecular networks is believed to determine important aspects of their cellular function, such as the organismal resilience against random perturbations. Ultimately, however, cellular behaviour is determined by the dynamical processes, which are constrained by network topology. The present work is based on a fundamental relation from dynamical systems theory, which states that the macroscopic resilience of a steady state is correlated with the uncertainty in the underlying microscopic processes, a property that can be measured by entropy. Here, we use recent network data from large-scale protein interaction screens to characterize the diversity of possible pathways in terms of network entropy. This measure has its origin in statistical mechanics and amounts to a global characterization of both structural and dynamical resilience in terms of microscopic elements. We demonstrate how this approach can be used to rank network elements according to their contribution to network entropy and also investigate how this suggested ranking reflects on the functional data provided by gene knockouts and RNAi experiments in yeast and Caenorhabditis elegans. Our analysis shows that knockouts of proteins with large contribution to network entropy are preferentially lethal. This observation is robust with respect to several possible errors and biases in the experimental data. It underscores the significance of entropy as a fundamental invariant of the dynamical system, and as a measure of structural and dynamical properties of networks. Our analytical approach goes beyond the phenomenological studies of cellular robustness based on local network observables, such as connectivity. One of its principal achievements is to provide a rationale to study proxies of cellular resilience and rank proteins according to their importance within the global network context.     

The impact of diaphragm management on prolonged ventilator support after thoracoabdominal aortic repair

PURPOSE: The relationship of the division of the diaphragm during thoracoabdominal aortic repair to prolonged ventilator support has not been studied. The purpose of this study was (1) to determine whether preservation of diaphragm integrity has a significant effect on postoperative ventilator duration and (2) to elucidate other pulmonary risk factors related to thoracoabdominal aortic surgery and to study the relationship of these factors to the intact diaphragm technique. METHODS:Between February 1991 and January 1997, we repaired 397 descending and thoracoabdominal aortic aneurysms. Descending thoracic aneurysms were not included in the study because their repair does not include the diaphragm. A total of 256 patients participated in this study. The diaphragm was divided in 150 patients and left intact in 106 patients. Examined as potential risk factors were patient demographics, history and physical findings, aneurysm extent, urgency of the procedure, acute dissection, cross-clamp time, homologous and autologous blood product consumption, and adjunctive operative techniques. FEV1 also was considered in the 197 patients for whom preoperative spirometry was available. Prolonged mechanical ventilation was defined as ventilator support for >72 hours. Data were analyzed by univariate contingency table and multiple logistic regression methods. RESULTS: Increasing age (odds ratio [OR], 1.02/y; P <.02), current smoking (OR, 2.6; P <.0008), total cross-clamp time (OR, 1.0/min; P <.008), units packed red blood cells transfused (OR, 1.06/unit; P <.008), and division of the diaphragm (OR, 2.03; P <.02) were significant, independent predictors of prolonged ventilation. Sixty-seven percent of patients (71 of 106) whose diaphragms were preserved were extubated in <72 hours compared with 52% of patients (78 of 150) who underwent diaphragm division (OR, 0.53; P <.02). CONCLUSION: Independently of well known pulmonary risk factors, an intact diaphragm during thoracoabdominal aortic repair results in a higher probability of early ventilator weaning.     

In‐situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation,Part 1: Organoclay nanocomposites

Effective dispersion of organically modified montmorillonite‐layered silicates in nylon 66 is addressed by synthesizing nanocomposites in situ via interfacial polycondensation from a suspension of silicate platelets in one of the monomer phases using either a stirred or unstirred reactor, while avoiding the detrimental heat history associated with melt compounding of this high melting polymer system. The effects of mixing methodology, reaction conditions, concentration ratio, and clay content are evaluated to elucidate process mechanisms and produce high molecular weight product. Enhanced stiffness of the nanocomposites measured by tensile modulus is related to their nanoscale morphology as characterized by transmission electron microscopy and wide angle X‐ray diffraction. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers     

In situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation. II. Sodium montmorillonite nanocomposites

Interfacial polycondensation (IPC) is used to generate polyamide 66 (PA66) nanocomposite using sodium montmorillonite (NaMMT), which offers better thermal stability than organically modified montmorillonite. Several approaches are used to obtain different levels of dispersion for studying the factors affecting dispersion of NaMMT layered‐silicates. These approaches include dispersing NaMMT in either aqueous media or in a compatible nonaqueous medium. Moreover, clay slurry was added to the reaction media separately or in combination with the aqueous hexamethylenediamine solution, which includes either excess amine or sodium carbonate as the by‐product scavenger, in order to study the effect of sequencing on the dispersion of NaMMT. Several characterization techniques including dynamic mechanical analysis, wide angle X‐ray diffraction, and transmission electron microscopy are used to examine the structure and relate it to the mechanical properties of the nanocomposites. Results show that in situ polymerization techniques predominantly give rise to hybrid exfoliated–intercalated NaMMT structure. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers