On the dynamics of mechanical milling in a vibratory mill

The dynamics of mechanical milling in a vibratory mill have been studied by means of mechanical vibration, shock measurements, computer simulation and microstructural evolution measurements. Two distinct modes of ball motion during milling, periodic and chaotic vibration, were observed. Mill operation in the regime of periodic vibration, in which each collision provides a constant energy input to milled powders, enabled a quantitative description of the effect of process parameters on system dynamics. An investigation of the effect of process parameters on microstructural development in an austenitic stainless steel showed that the impact force associated with collision events is an important process parameter for characterizing microstructural evolution. (C) 1997 Elsevier Science S.A.

Finite element analysis of mechanical properties in discontinuously reinforced metal matrix composites with ultrafine microstructure

This investigation focused on the finite element analyses of elastic and plastic properties of aluminium/alumina composite materials with ultrafine microstructure. The commonly used unit cell model was used to predict the elastic properties. By combining the unit cell model with an indentation model, coupled with experimental indentation measurements, the plastic properties of the composites and the associated strengthening mechanism within the metal matrix material were investigated. The grain size of the matrix material was found to be an important factor influencing the mechanical properties of the composites studied. (C) 1997 Elsevier Science S.A.

Models of alcohol use by young adults: An examination of various attitude-behavior theories

Objective: The aim of this study was to test the effectiveness of various attitude-behavior theories in explaining alcohol use among young adults. The theory of reasoned action (TRA), the theory of planned behavior and an extension of the TRA that incorporates past behavior were compared by the method of maximum-likelihood estimation, as implemented in LISREL for Windows 8.12. Method: Respondents consisted of 122 university students (82 female) who were questioned about their attitudes, subjective norms, perceived behavioral control, past behavior and intentions relating to drinking behavior. Students received course credit for their participation in the research. Results: Overall, the results suggest that the extension of the theory of reasoned action which incorporates past behavior provides the best fit to the data. For these young adults, their intentions to drink alcohol were predicted by their past behavior as well as their perceptions of what important others think they should do (subjective norm). Conclusions: The main conclusions drawn from the research concern the importance of focusing on normative influences and past behavior in explaining young adult alcohol use. Issues regarding the relative merit of various alternative models and the need for greater clarity in the measure of attitudes are also discussed.

Children's cooperative behavior and interactions in trained and untrained work groups in regular classrooms

This study examined group and individual factors that facilitate changes in cooperation and learning outcomes in trained and untrained work groups of elementary school-age children. The study had two foci. The first was to determine if the cooperative behaviors and interactions of children in classroom groups who were trained in cooperative learning skins were different from those of children who were given no training, and the second was to investigate small group interactions and achievement in these groups over time. The results showed that there were observable differences between student interactions in the two conditions and these differences were maintained over time. Compared with children in the untrained groups, those in the trained groups were consistently more cooperative and helpful to each other; they actively tried to involve each other in the learning task by using language which was more inclusive (e.g., frequent use of ''we''), and they gave more explanations to assist each other as they worked together. It appeared that as the children worked together over time, they became more responsive to the learning needs of each other. Furthermore, the children in the trained groups performed significantly better on the learning outcomes questionnaire than those in the untrained groups. (C) 1997 Society for the Study of School Psychology. Published by Elsevier Science Ltd.

Cue exposure in moderation drinking: A comparison with cognitive-behavior therapy

To date, the published controlled trials on exposure to alcohol cues have had an abstinence treatment goal. A modification of cue exposure (CE) for moderation drinking, which incorporated priming doses of alcohol, could train participants to stop drinking after 2 to 3 drinks. This study examined the effects of modified CE within sessions, combined with directed homework practice. Nondependent problem drinkers who requested a moderation drinking goal were randomly allocated to modified CE or standard cognitive-behavior therapy (CBT) for alcohol abuse. Both interventions were delivered in 6 90-min group sessions. Eighty-one percent of eligible participants completed treatment and follow-up assessment. Over 6 months, CE produced significantly greater reductions than CBT in participants' reports of drinking frequency and consumption on each occasion. No pretreatment variables significantly predicted outcome, The modified CE procedure appears viable for nondependent drinkers who want to adopt a moderate drinking goal.

A semi-empirical approach to optimise the quantity of drying aids required to spray dry sugar-rich foods

A semi-empirical linear equation has been developed to optimise the amount of maltodextrin additive (DE 6) required to successfully spray dry a sugar-rich product on the basis of its composition. Based on spray drying experiments, drying index values for individual sugars (sucrose, glucose, frutose) and citric acid were determined, and us;ng these index values an equation for model mixtures of these components was established. This equation has been tested with two sugar-rich natural products, pineapple juice and honey. The relationship was found to be valid for these products.

Follow-up of Pregnant Women With Autoimmune Hepatitis The Disease Behavior Along With Maternal and Fetal Outcomes

Goals: To assess maternal and fetal outcomes and clinical management of pregnancy in patients with autoimmune hepatitis (AIH). Background: There is a paucity of information about maternal and fetal outcomes, and AIH activity during pregnancy and in the postpartum period. There is no consensus about the administration of azathioprine during pregnancy and breastfeeding. Study: Retrospective analysis of 54 pregnancies (3 still in progress) in 39 AIH patients. Results: The median age at conception was 24 years, and 68.4% of women had liver cirrhosis. Before conception and in early pregnancy, azathioprine and prednisone were administered in 48.1%, but treatment regimen vas usually changed further to 20 mg/d prednisone and 20.4%, were off treatment. There were 36 livebirths, and fetal loss rates were 29.4% (13 miscarriages, 1 stillbirth, and 1 ectopic pregnancy). Preterm birth rate was 11.8%. In 2 cases, there was acute fetal distress; and in 2 others congenital malformations (3.9%). The rate of serious maternal complication was 7.8%, with no deaths. There were no flares in 41.2% pregnancies, but aminotransferase elevations occurred in 54.9%, 31.4% of which were true AIH relapses, only registered in the postpartum period. Conclusions: Despite the high fetal miscarriage rate, pregnancy in AIH was safe. Patients needed careful monitoring, especially in the postpartum period because of relapses. There was no evidence of a cause and effect relationship among azathioprine administration and premature births and congenital abnormalities, but more studies are necessary. Higher doses of prednisone may be an alternative option for those who prefer azathioprine withdrawal during pregnancy.

Acinar cell carcinoma of the pancreas: is the absence of neuroendocrine component related to a more malignant behavior?

Background/Aims: Acinar cell carcinomas are uncommon malignant tumors of the pancreas, accounting for 1-2% of all the cases of exocrine pancreatic tumor. Some authors have estimated acinar cell tumors to be as aggressive as ductal adenocarcinoma of the pancreas whereas other series showed acinar cell tumors to have a favorable clinical outcome. This discrepancy in prognosis may be related to the cellular components of the tumor. Methodology: With the aim to evaluate the possible relationship between the presence of neuroendocrine differentiation and behavior of these tumors, the authors reviewed all patients presenting acinar cell carcinoma of the pancreas in the last 5 years with emphasis in the immunohistochemical evaluation. Results: Four patients presented neuroendocrine differentiation on immunohistochemical evaluation and had a more benign outcome. Two patients without neuroendocrine component had a disseminated disease at presentation. This data suggests that this tumor is less aggressive than ductal adenocarcinoma and even with nodal involvement, long term survival after complete resection can be achieved. Conclusions: It is possible that the absence of neuroendocrine component may be related to a less favorable outcome and adjuvant therapy may be necessary. Due to the rarity of this pancreatic tumor, this relationship remains to be confirmed with a multicentric study including a larger number of patients.

Sexual behavior and knowledge of sexually transmitted infections among university students in Sao Paulo, Brazil

Objective: To investigate the sexual behavior and knowledge about sexually transmitted infections (STIs) among undergraduate students in Sao Paulo, Brazil. Methods: Self-reported questionnaires were used. Results: Most of the 447 students in the study were single (97.3%), in their first year of university (87.7%), and the mean ages were 20.4 years (males) and 19.8 years (females). Vaginal intercourse was practiced by 69.7% of males and 48.4% of females, oral sex by 64.5% of males and 43.7% of females, and anal sex by 18.4% of males and 14.1% of females. Use of a condom during vaginal sex was practiced by 80.4% of males and 74.8% of females and during anal sex by 47.8% of males and 30.0% of females. Knowledge of transmission of STIs was greater than 90% for HIV, syphilis, genital herpes, and gonorrhea; 63%-76% for HPV and genital warts; 30%-34% for Trichomonas and only 16% for Chlamydia. Only 25%-34% knew that HIV was transmitted by breastfeeding; 56%-60% knew that HIV was transmitted by anal sex. Conclusion: Many students engage in high-risk sexual behavior with multiple partners and use condoms inconsistently. Knowledge of the acquisition and modes of sexual and vertical transmission of HIV are strikingly deficient. (C) 2010 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.

Prone position prevents regional alveolar hyperinflation and mechanical stress and strain in mild experimental acute lung injury

Prone position may delay the development of ventilator-induced lung injury (VILI), but the mechanisms require better elucidation. In experimental mild acute lung injury (ALI), arterial oxygen partial pressure (Pa(O2)), lung mechanics and histology, inflammatory markers [interleukin (IL)-6 and IL-1 beta], and type III procollagen (PCIII) mRNA expressions were analysed in supine and prone position. Wistar rats were randomly divided into two groups. In controls, saline was intraperitoneally injected while ALI was induced by paraquat. After 24-h, the animals were mechanically ventilated for 1-h in supine or prone positions. In ALI, prone position led to a better blood flow/tissue ratio both in ventral and dorsal regions and was associated with a more homogeneous distribution of alveolar aeration/tissue ratio reducing lung static elastance and viscoelastic pressure, and increasing end-expiratory lung volume and Pa(O2). PCIII expression was higher in the ventral than dorsal region in supine position, with no regional changes in inflammatory markers. In conclusion, prone position may protect the lungs against VILI, thus reducing pulmonary stress and strain. (C) 2009 Elsevier B.V. All rights reserved.