Production and partial characterization of alkaline polygalacturonase secreted by thermophilic Bacillus sp. SMIA-2 under submerged culture using pectin and corn steep liquor

Polygalacturonase production by the thermophilic Bacillus sp. SMIA-2 cultivated in liquid cultures containing 0.5% (w/v) apple pectin and supplemented with 0.3% (w/v) corn steep liquor, reached its maximum after 36 hours with levels of 39 U.mL-1. The increase in apple pectin and corn steep liquor concentrations in the medium from 0.5 and 0.3%, respectively, to 0.65%, markedly affected the production of polygalacturonase, whose activity increased four times, reaching a maximum of 150.3 U.mL-1. Studies on polygalacturonase characterization revealed that the optimum temperature of this enzyme was between 60-70 °C. Thermostability profile indicated that the enzyme retained about 82 and 63% of its activity at 60 and 70 °C, respectively, after 2 hours of incubation. The optimum pH of the enzyme was found to be 10.0. After incubation of crude enzyme solution at room temperature for 2 hours at pH 8.0, a decrease of about 29% on its original activity was observed. At pH 10.0, the decrease was 25%.

Partial substitution of nitrite by chitosan and the effect on the quality properties of pork sausages

The aim of the study was to evaluate the influence of partial nitrite replacement by chitosan on the quality of Ham Visking (a type of pork sausages). Five Ham Visking formulations were elaborated modifying the sodium nitrite (0.011; 0.016 or 0.0212%) and chitosan concentrations (0.25 or 0.5%) in the products. Sausages were stored at 4 ºC and physicochemical, microbiological, and sensorial evaluations were performed in order to estimate their shelf life. Chitosan can be used in pork sausages without affecting ensory attributes such as color although the panelists detected textural differences among the samples with chitosan, which suggests that there is some influence of deacetylation degree of chitosan on the textural behavior of sausages which still needed to be explained for a successful application of chitosan in meat products. The reduction of residual sodium nitrite did not affect the color and flavor of such products, but the use of chitosan increasedsignificantly the shelf life of sausages.

Partial chemical and functional characterization of milk whey products obtained by different processes

Whey protein samples (S-1 to S-5) were tested in vivo and in vitro for nutritional properties and selected bioactivities. Weanling male Wistar rats fed modified AIN-93G (12 g protein.100 g-1) diets for 21 days were used the in vivo studies. The nutritional parameters did not differ among the protein diets tested. Erythrocyte glutathione content was considered high and was higher for S-3, but liver glutathione was the same for all dietary groups. For S-3, cytokine secretion (IL-10 and TNF-α) by human peripheral blood mononuclear cells (in RPMI-1640 medium) was higher in the absence of antigen than in the presence of BCG antigen. Interleukin-4 secretion was repressed in all treatments. The IC50, whey protein concentration required to inhibit 50% of the melanoma cell proliferation, was 2.68 mg.mL-1 of culture medium for the S-3 sample and 3.66 mg.mL-1 for the S-2 sample. Based on these results, it was concluded that S-3 (whey protein concentrate enriched with TGF-β and lactoferrin) produced better nutritional and immunological responses than the other products tested.

Effect of the addition of wheat fiber and partial pork back fat on the chemical composition, texture and sensory property of low-fat bologna sausage containing inulin and oat fiber

The objective of this work was to study the effect of adding wheat fiber and partial pork back fat on the quality characteristics of bologna sausage. The compound central rotating design was used with treatments containing fixed levels of inulin (5%) and oat fiber (1%) and variable levels of wheat fiber (0-4%) and pork back fat (0-10%). The pH and protein were similar in all the treatments, the fat was lower than the control treatment and the moisture content was higher than the control treatment (CF) without fibers. The wheat fiber increased the hardness and reduced cohesiveness and scores were given for overall impression. We found that it was possible to prepare low-fat bologna sausage with the addition of 6.58% fiber (5% inulin, 1% oat fiber and 0.58% wheat fiber), whilst retaining good sensory acceptability, thus reducing the pork back fat levels by between 25 and 42.75%.

Purification, partial characterization and antimicrobial activity of Lectin from Chenopodium Quinoa seeds

Abstract A novel lectin was isolated from the seeds of Chenopodium quinoa. To achieve this end, the crude extract from the quinoa was submitted to two purification steps, Sephadex G50 and Mono Q. The hemagglutinating activity showed that this lectin agglutinates human erythrocytes. Its activity is inhibited by glucose and mannose, and remained stable under a wide range of pH levels and temperatures. The quinoa lectin was found to be a heterodimeric lectin of approximately 60 kDa, consisting of two subunits of approximately 25 kDa and 35 kDa. This lectin had its antimicrobial activity tested against several bacteria strains and effectively inhibited three strains. These strains were all Gram-negative, making this lectin a promising antimicrobial tool.

Physicochemical characteristics and sensory acceptability of ready-to-eat sliced frozen roast beef with partial reduction of sodium chloride

Abstract Sodium chloride in meat products provides microbiological stability and desirable technological and sensory effects. Therefore, the reduction of this ingredient is a challenge for the meat industry. The objective of this study was to evaluate the physicochemical and sensory characteristics of ready-to-eat sliced frozen roast beef with partial replacement of sodium chloride by a commercial additive mostly composed of potassium chloride. The analyses performed were chemical composition, cooking yield and post defrosting loss, microbiological evaluation and sensory analysis. There was higher moisture content (p < 0.05) in the control treatment (without the presence of the replacement additive) and all treatments were not different (p ≥ 0.05) in the cooking yield and in post-defrosting loss. The results of microbiological analysis are according to Brazilian Legislation. The sensory evaluation showed no difference between the control treatment and the T1 treatment (with the reduction of 35% of NaCl), while the T2 treatment (with reduction of 70% of NaCl) had the lowest average values in all attributes. The study showed that the reduction of 35% NaCl for commercial additive, mostly composed of potassium chloride, in roast beef is feasible since no changes were observed in sensory and technological characteristics evaluated.

Partial characterization of genes from the embryonic axis of Melanoxylon brauna Schott. (Leguminosae-Caesalpinioideae) seeds

The objective of this study was to partially characterize some genes involved in the desiccation tolerance of the embryonic axis of Melanoxylon brauna seeds subjected, or not, to oven fast-drying. Seeds were initially dried rapidly in an oven at 40 ºC, 50 ºC, 60 ºC, 70 ºC, and 80 °C, for 24, 48 and 72 h and then subjected to germination tests and moisture content determination. Degenerate primers were designed for 19 genes. The CDNA was used as a template for PCR amplifications using the degenerate primers, and the PCR products obtained were purified, cloned and sequenced. The seeds showed a gradual reduction in percent germination with increasing temperature and drying time. Nucleotide sequences of the cloned fragments related to genes CAT1, SPS1, Abi5, Transk and PM25 were obtained. The similarity analysis with the sequences deposited in databases revealed similarities with genes CAT1, SPS1, Transk and PM25 from other plant species. The nucleotide sequences obtained from the respective genes will be used for designing specific primers for gene expression analyses during seed germination in order to understand the causes for loss of physiological quality of Melanoxylon brauna seeds.

Monitoring Directed Energy Deposition Processes in Additive Manufacturing

The purpose of this study is to find out how laser based Directed Energy Deposition processes can benefit from different types of monitoring. DED is a type of additive manufacturing process, where parts are manufactured in layers by using metallic powder or metallic wire. DED processes can be used to manufacture parts that are not possible to manufacture with conventional manufacturing processes, when adding new geometries to existing parts or when wanting to minimize the scrap material that would result from machining the part. The aim of this study is to find out why laser based DED-processes are monitored, how they are monitored and what devices are used for monitoring. This study has been done in the form of a literature review. During the manufacturing process, the DED-process is highly sensitive to different disturbances such as fluctuations in laser absorption, powder feed rate, temperature, humidity or the reflectivity of the melt pool. These fluctuations can cause fluctuations in the size of the melt pool or its temperature. The variations in the size of the melt pool have an effect on the thickness of individual layers, which have a direct impact on the final surface quality and dimensional accuracy of the parts. By collecting data from these fluctuations and adjusting the laser power in real-time, the size of the melt pool and its temperature can be kept within a specified range that leads to significant improvements in the manufacturing quality. The main areas of monitoring can be divided into the monitoring of the powder feed rate, the temperature of the melt pool, the height of the melt pool and the geometry of the melt pool. Monitoring the powder feed rate is important when depositing different material compositions. Monitoring the temperature of the melt pool can give information about the microstructure and mechanical properties of the part. Monitoring the height and the geometry of the melt pool is an important factor in achieving the desired dimensional accuracy of the part. By combining multiple different monitoring devices, the amount of fluctuations that can be controlled will be increased. In addition, by combining additive manufacturing with machining, the benefits of both processes could be utilized.

The Literary relations between La Fontaine and the "Astrée" of Honoré d'Urfé : a dissertation presented to the faculty of the department of philosophy of the university of Pennsylvania in partial fulfilment of the requirements for the degree of doctor of philosophy / by Walther P. Fischer

Collection : Publications of the University of Pennsylvania ; n° 6

Self-directed learning, stress and the adult learner /

The purpose of this correlational study was to investigate the relationship between the degree of self-directed learning readiness and stress for level one nursing students and level two nursing students. One hundred female nursing students participated in the study who were attending an Ontario Community College. Data were collected from the main nursing campus and the satellite nursing campus using the random sample method. Instruments used were said to be valid and reliable for testing self-directed learning readiness and stress respectively. Data were analyzed using frequency response to each item, means and standard deviation, and the Pearson product correlation between selfdirected learning readiness and stress. The results of the study show that there is a difference in the relationship between the degree of self-directed learning readiness and stress between the level one nursing students and the level two nursing students. Such results will be of particular interest to nursing instructors and administrators when planning for delivery of programs to such students.

An examination of learning resulting from a transition from a directed to a self-directed work environment

~ This study focuses on the process of self-directed learning that individuals go through as they adapt to new work situations. This is a study of how one critical incident, specifically the transition from a traditional office structure to a home office structure, affected employees and what their learning process was as they adapted to the new environment. This study has 3 educational foundations: adult learning, self-directed learning, and the social context from which the learning will occur. Six women and 2 men were interviewed approximately 1 year following the transition. Analysis of the data revealed 5 themes of: impacts of the self-directed environment on participants' personal lives, their roles, skill set, productivity, and the physical environment; support offered by the organization, family, and office administration; personal development, specific learning needs, and personal skills; boundaries as they relate to family and work; and skill set and orientation requirements of new home office employees. The findings revealed the learning processes of the 8 participants. The learning processes of these participants were discussed within a theoretical framework of the learners, their immediate surroundings, and the larger social environment. The results indicated that the transition from a directed work environment to a self directed work environment is a complex, interrelated process. An element found throughout the theoretical framework is that of control. A second critical element is the need for participants to have a clearly defined work role and an opportunity to engage in discussion with peers and the community. Further findings reinforced the importance of climate and found that the physical environment is a key factor in a successful selfdirected work environment. The findings of this study revealed that no one factor makes an individual function successfully in a self-directed work environment, but that it is a complex interplay among the leamer, their immediate surroundings, and the social environment that will have the greatest impact on success. Recommendations are made which can be used to guide organizational leaders in facilitating employees' transition from a directed to a self-directed work environment. Additionally, recommendations are made for further research in the area of self-directed work environments.

A study of self-directed learning at an Ontario college of applied arts and technology

Ontario Colleges of Applied Arts and Technology (CAATs) are currently in the process of restructuring to ensure quality, accountability, and accessibility of college education. References to learner involvement and self-directed learning are prevalent. "Alternative delivery" and "paradigm shift" are current buzzwords within the Ontario CAAT system as an environment is created supportive of change. Instability of funding has also dictated a need for change. Therefore, a focus has become quality of learning with less demand on public resources. This qualitative case study was conducted at an Ontario CAAT to gather descriptive, perceptual data from post-secondary community college educators who were identified as supportive of self-directed learning and from post-secondary, traditional-aged college students who were perceived by their educators to be selfdirected learners. This college was selected because of initiatives to modify its academic paradigm to encourage what was reputed in the Ontario CAAT system to be self-directed learning. The purpose of this study was to investigate how postsecondary, traditional-aged college students and their educators perceive self-directed learning as part of the teaching-learning experience within a community college setting. Educator participants of the study were selected based on the results of a teaching and learning survey intended to identify educators supportive of self-directed learning. A total of 317 surveys were distributed to every full-time educator at the sample college; 192 completed surveys were returned for a return rate of 61 %. Of these, 8% indicated instructional beliefs and values supportive of self-directed learning. A purposive sample of six educators was selected using a maximulp variation sampling strategy. A network selection sampling strategy was used to select a purposive sample of seven post-secondary students who were identified by the sample educators as selfdirected learners. The results of the study show that students and educators have similar perspectives and operating definitions of self-directed learning and all participants believe they either practice or facilitate self-directed learning. However, their perspectives and practices are not consistent with the literature which emphasizes learner autonomy or control in course structure and content. A central characteristic of the participants represented in this study is the service-oriented professions with which each is associated. Experientiallearning opportunities were highly valued for the options provided in increasing learner independence and competencies in reflective practice. Although there were discrepancies between espoused theory and theory in practice in terms of course structure, the process of self-directed learning was being practiced and supported outside the classroom structure in clinical settings, labs and related experiences.

Facilitating self-directed learning: the nurse educators' perspective

The concept of self-directed learning was examined from the nurse educators' perspective. One structured interview, lasting between one and one-and-a half hours, was conducted with each of 14 nurse educators in two community college continuing education programs in nursing. One community college program encourages selfdirected learning; the other encourages self-study and active participation in the teaching/learning process. All 14 interviews were tape-recorded and transcribed verbatim. Verbatim transcripts were analyzed for themes, patterns, and relationships utilizing analyst-constructed typologies. six prerequisites or necessary conditions for facilitating self-directed learning in a community college continuing education program in nursing were identified. ~he crucial issue in facilitating self-directed learning was found to be the issue of teacher-control.

Instructor support for self-directed learning in higher education

This study addressed the problem of instructor support for self-directed learning, specifically, learner-directed program planning, within a classroom setting in higher education. A combination of survey, interview, document analysis, and observation was used to assess and evaluate the attitudes and practices of a sample of full-time faculty at an Ontario university. Eighty-seven percent of the study sample reported instructional beliefs, values, and expectations that were not supportive of self-directed learning, especially in terms of student participation in program planning. Planning was seen as the responsibility of the instructor. Instructors were least open to student participation in the planning of the evaluation of learning. However, there was considerable stated support for other of the basic principles of adult education. The remaining 13% of the study sample reported instructional beliefs, values, and expectations that were fully supportive of self-directed learning. Instructional practices were analyzed in relation to the instructors' stated beliefs. Although practices reflected, in many instances, instructors' statements of support, there were some significant discrepancies between apparent support for the concept of self-directed learning and actual classroom practice. Both beliefs and practice were compared to a research model of self-directed learning. Most instructors did not have a concept of self-directed learning as comprehensive as that described in the research model. Instructor support for self-directed learning was profoundly influenced by the university setting. It was concluded that more strenuous attempts to research, enhance, and promote instructional and institutional support for self-directed learning in higher education are warranted.