Recovery of Components from Shrimp (Xiphopenaeus kroyeri) Processing Waste by Enzymatic Hydrolysis

ABSTRACT:  Industrial shrimp waste is a good source of protein, chitin, and carotenoids. In general, this waste is discarded with no attempt to use it, thus contributing to environmental pollution. This study was aimed at recovering the 3 main components of industrial shrimp waste, protein, chitin, and astaxanthin, using enzymatic treatment with Alcalase and pancreatin. An increase in the degree of hydrolysis (DH) from 6% to 12% resulted in 26% to 28% protein recovery. Alcalase was more efficient than pancreatin, increasing the recovery of protein from 57.5% to 64.6% and of astaxanthin from 4.7 to 5.7 mg astaxanthin/100 g of dry waste, at a DH of 12%. The enzymatic hydrolysis of the industrial waste from Xiphopenaeus kroyeri shrimp using Alcalase allowed for 65% protein recovery in the form of hydrolysates, in addition to providing suitable conditions for the recovery of astaxanthin and chitin.     

Influence of Pressure and Temperature on the Velocity of a Turbulent Jet Flow 3D

To investigate the influence of pressure and temperature on the jet velocity of a three-dimensional flow was the main goal of this study. Using a precipitation chamber with approximate capacity of 600 mL, it was studied the thermodynamic behavior of supercritical carbon dioxide mixture, dichloromethane and grape seed extract via SAS （supercritical antisolvent process）. For the numerical solution, the Navier-Stokes equations were used along with the model of turbulence k-ε and Peng-Robinson equation of state with quadratic mixing rules of Van der Waals. The method of Chung was employed to determine the viscosity, thermal conductivity and mass diffusivity of the flow numerically solved through commercial code based on CFD （computational fluid dynamics）. Simulations for pressures between 80 bar and 160 bar and temperatures between 308.15 K and 318.15 K showed large variations in the jet velocity, an important property in the dynamic mixing process that involves the size, size distribution and particle morphology.     

Investigating heavy metal resistance, bioaccumulation and metabolic profile of a metallophile microbial consortium native to an abandoned mine

Contaminated sites represent new ecological niches where historical pollution has originated an unusual microbial biodiversity. The knowledge of these microorganisms contributes to the discovery of new pathways and metabolic networks and may offer potential solutions for damaged areas. In the present work seven microbial consortia have been isolated from an abandoned mine of blend and galena (Ingurtosu, Italy) through a selection for resistance to zinc (tested up to 40 mM in solution). All the consortia were able to accumulate zinc and the best accumulator, named Ing5, has been studied for the following characteristics: resistance and accumulation of Zn, Cd, Hg, bioaccumulation mechanisms of Zn, and influence of Zn and Cd on the metabolic profile. The results indicate that the consortium Ing5 bears resistance systems for Cd and Hg as well as Zn and that, for some of the 5 isolates belonging to Ing5, the resistance thresholds are higher in consortium than in pure culture. The prevalent mechanism for zinc accumulation can be reasonably considered to be metabolism-dependent, inducible and regulated by metal concentrations. The study on the metabolic profile, carried out by the Biolog system, shows that Zn exerts a very low influence on the metabolic profile and that this influence can also be positive; Cd has a stronger negative influence but that, despite this, the consortium is able to maintain a wide metabolic potential in the presence of heavy metals. These features of Ing5 make it a good candidate for biotechnological applications and for further investigation of the degradation of organic pollutants in the presence of metals.     

Search based constrained test case selection using execution effort

Software testing is essential to guarantee high quality products. However, it is a very expensive activity, particularly when manually performed. One way to cut down costs is by reducing the input test suites, which are usually large in order to fully satisfy the test goals. Yet, since large test suites usually contain redundancies (i.e., two or more test cases (TC) covering the same requirement/piece of code), it is possible to reduce them in order to respect time/people constraints without severely compromising coverage. In this light, we formulated the TC selection problem as a constrained search based optimization task, using requirements coverage as the fitness function to be maximized (quality of the resultant suite), and the execution effort (time) of the selected TCs as a constraint in the search process. Our work is based on the Particle Swarm Optimization (PSO) algorithm, which is simple and efficient when compared to other widespread search techniques. Despite that, besides our previous works, we did not find any other proposals using PSO for TC selection, neither we found solutions treating this task as a constrained optimization problem. We implemented a Binary Constrained PSO (BCPSO) for functional TC selection, and two hybrid algorithms integrating BCPSO with local search mechanisms, in order to refine the solutions provided by BCPSO. These algorithms were evaluated using two different real-world test suites of functional TCs related to the mobile devices domain. In the performed experiments, the BCPSO obtained promising results for the optimization tasks considered. Also, the hybrid algorithms obtained statistically better results than the individual search techniques.     

A methodological and substantive note on the performance-cue effect in ratings of work-group behavior.

According to research on the performance-cue effect in work ratings, knowledge that a group performed well or poorly can trigger raters' implicit theories, resulting in inaccurate judgments of the group's behavior. Unfortunately, because information concerning group performance has always been provided by the experimenter, it has been impossible to tell whether the performance-cue effect reflects the influence of participants' implicit theories or is simply an attempt to conform to the experimenter's belief. To test these 2 explanations, participants observed a work group without having received performance information and then completed evaluative and behavioral ratings of the group. Allowing participants to evaluate the group free of any externally provided performance information enabled participants to form independently generated impressions; thus, the demand characteristic problem was eliminated. Results indicated the performance-cue effect is not an artifact and that it is likely due to a systematic response bias. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Long-term captopril therapy in asymptomatic patients with severe chronic aortic insufficiency

BACKGROUND: Clinical history of patients with severe chronic aortic regurgitation is characterized by a long period without any symptom, although the left ventricle enlarges progressively. The administration of oral vasodilators could reduce ventricular enlargement or its progression, delaying the development of myocardial dysfunction and/or the need for valvular surgery. OBJECTIVES: To verify the efficacy of long-term captopril therapy to reduce left ventricular mass and dimensions in patients with severe chronic aortic regurgitation. METHODS: This is a prospective echocardiographic study in which each individual patient is considered his own control case. Eleven asymptomatic patients with severe chronic aortic regurgitation in sinus rhythm, who had an ejection fraction greater than 50% and were not taking cardiovascular drugs, were orally administered captopril at the maximum tolerated dosage (127 +/- 13 mg/day). Follow-up lasted for 24 +/- 3 months. RESULTS: Left ventricular telediastolic diameter decreased from 69 +/- 5 to 61 +/- 3 mm (p < 0.01), telesystolic diameter decreased from 48 +/- 5 to 41 +/- 4 mm (p < 0.01); ejection fraction increased from 56 +/- 4 to 61 +/- 3% (p < 0.001); myocardial mass decreased from 208 +/- 32 to 174 +/- 27 g/m2 (p < 0.01), and mean wall stress from 264 +/- 35 to 203 +/- 25 mmHg (p < 0.001). All variations were still significant at 6 months. CONCLUSIONS: These results suggest that captopril has a favourable effect on left ventricular mass, dimensions and load conditions, and could favourably influence the natural history of chronic aortic regurgitation. The efficacy of medical treatment can be verified through serial echocardiographic study.     

Temperature dependent DC characteristics of an InP/InGaAs/InGaAsPHBT

We report the DC characteristics of n-p-n InP/InGaAs/InGaAsP HBT's which have a composite-collector structure designed to improve the breakdown and gain. The devices exhibit common-emitter current gain of greater than 8 for over 9 orders of magnitude of collector current and breakdown voltages greater than 10 V. The DC gain for a typical device decreases from 40 at room temperature to 8 at 90 K. Over the same temperature range the collector-current ideality factor increases from 1.04 to 1.46, and the base current ideality factor is 0.05 to 0.1 larger than these values. We suggest that the high collector-current ideality factor and the lower gain at the lower temperatures is due to the increasing importance of tunneling of current across the emitter-base junction. The devices with the InGaAs/InGaAsP composite-collector structure offer better common-base turn-on behavior than those with InGaAs/InP as the collector structure, without the breakdown behavior being compromised     

A model of e-commerce adoption (MOCA): consumer's perceptions and behaviours

The paper analyses factors that usually influence the adoption of online commerce, focusing in particular on how social influence acts in this process considering in particular an Italian sample. It investigates about the actual transaction behaviour, and not just the intention to shop online. Starting from analysing technology acceptance models of literature, the paper proposes and empirically validates a new model for e-commerce adoption. A self-administered survey approach was used to collect data from a sample of different ages, genders and educational levels by using a structured questionnaire. Empirical data were analysed using correlation and regression analysis. Results showed that social influence, usability and perceived usefulness are predictors of the frequency of use and then, of e-commerce adoption. The paper gives both a theoretical and an empirical contribution to the e-commerce literature by designing and testing a model for predicting online consumers’ behaviour and enhancing the e-commerce adoption understanding.