Silanol-Assisted Carbinolamine Formation in an Amine-Functionalized Mesoporous Silica Surface: Theoretical Investigation by Fragmentation Methods

The aldol reaction catalyzed by an amine-substituted mesoporous silica nanoparticle (amine-MSN) surface was investigated using a large molecular cluster model (Si392O958C6NH361) combined with the surface integrated molecular orbital/molecular mechanics (SIMOMM) and fragment molecular orbital (FMO) methods. Three distinct pathways for the carbinolamine formation, the first step of the amine-catalyzed aldol reaction, are proposed and investigated in order to elucidate the role of the silanol environment on the catalytic capability of the amine-MSN material. The computational study reveals that the most likely mechanism involves the silanol groups actively participating in the reaction, forming and breaking covalent bonds in the carbinolamine step. Therefore, the active participation of MSN silanol groups in the reaction mechanism leads to a significant reduction in the overall energy barrier for the carbinolamine formation. In addition, a comparison between the findings using a minimal cluster model and the Si392O958C6NH361 cluster suggests that the use of larger models is important when heterogeneous catalysis problems are the target

TCD4+ Lymphocyte are Related to Muscle Strength Parameters in HIV-1 Positive Adolescents: A Preliminary Study

Introduction: Catabolism of muscle and loss of function are complications that can occur during the course of HIV infection, and are commonly seen in a majority of adolescents with vertically transmitted Human Immunodeficiency Virus-type 1 (HIV-1). The levels of CD4+ and CD8+ lymphocytes, reference markers for the treatment of vertically transmitted HIV-1, also decline as the disease progresses. Alterations on these reference markers may be associated with neuromuscular force parameters in sedentary adolescents that have potential as prognostic indicators for treatment administration. Objective: To investigate the relationship between maximal isometric muscular contraction force and levels of CD4+ and CD8+ lymphocytes in sedentary, vertically transmitted HIV-1 positive adolescents. Methods: The sample consisted of twenty individuals, adolescents (N= 9 males, 11 females, age 15-17 years), vertically transmitted HIV-1 patients from Institute of Infectious Diseases Emilio Ribas in São Paulo, Brazil, who were undergoing HAART therapy randomly selected to participate in the study. The number of CD4+ and CD8+ cells was determined by flow cytometry using BD FacsCalibur Multitest Equipment, and Multiset-BD software. Viral load was determined using b-DNA methodology, on Siemens System Versátil 440 equipment. All analyses followed standard procedures approved by the Brazilian Ministry of Health. Muscular strength measurements were completed in the morning after blood collection and weight and height measurements. Prior to starting, patients were familiarized with all testing procedures and strength exercises that were used for testing. After the warm up, maximum voluntary isometric muscular strength of the elbow flexors and knee extensors were assessed using an electric dynamometer (EMG210C, EMGLAB System of Brazil). Each patient made three attempts with a rest interval of two minutes between trials. The highest isometric force and torque value were recorded and used for analyses. Results: Upper body force (r=0.70, p=0.001) and maximal torque (r=0.69, p=0.001) were significant correlated with CD4+ count. Similar observations between CD4+ count and lower body muscular force (r=0.62, p=0.005) and maximum torque (r=0.61, p=0.007) were also observed. CD8+ was not associated with any strength measures. Conclusion: CD4+ lymphocytes showed a strong correlation with force parameters in sedentary HIV-1 positive adolescents. Given that those individuals with higher TCD4+ counts showed a tendency towards manifesting higher muscle strength, this may be used as a predictor to indicate the level of physical capacity of patients and consequently help optimize treatment. Further research is needed to explore the potential prognostic value of muscle strength parameters in HIV-1 positive adolescents

Gene expression, biochemical and physiological activities in evaluating melon seed vigor through ethanol release.

The aim of the present study was to establish parameters to evaluate melon seeds vigor by ethanol release test using a modified ethylometer and correlate with physiological seed quality, gene expression and enzyme activities alterations. To perform this trial, six seeds lots of yellow melon were submitted to determinations such as moisture content, germination assay and vigor tests. 25 and 50 seeds soaked with 0.5 mL of distilled water and tested after 1, 2, 3, 4, 5, 6 and 24 h at 40 °C. After 0, 6 and 24 h of imbibition, the high and low vigor lots were evaluated for the following enzyme activity: superoxide dismutase (SOD), catalase (CAT), guaiacol peroxidase (GPX), ascorbate peroxidase (APX) and alcoholic dehydrogenase (ADH). Accumulation of ADH protein was verified using Western Blotting hybridization technique with the primary Anti-ADH antibody. The release of ethanol in 25 seeds, soaked in 0.5 mL of distilled water for 6 h, proved efficient for vigor evaluation and can be related to other traditionally used tests. Enzyme activity varied according to the vigor of the seed lot. For the protein profile, there was variation in the accumulation of proteins of specific molecular weights throughout the soaking periods. There was also variation in expression according to accumulation of ADH protein. The biochemical and molecular tests corroborate with the establishment of the ethanol test as an additional tool to evaluate seed vigor

Mapping social work across 10 countries: Structure, intervention, identity and challenges

An emerging global consciousness and rising attention given to international social work development has seen the recognition of comparative research within the profession. Understanding the functioning and organisation of social work within various country contexts is critical in order to formulate knowledge around its overall impact, successes and challenges, allowing social workers to learn from one another and build professional consolidation. The profession is mapped out in 10 countries, reflecting on its structure, identity and development. Although the profession is developing globally, it is also experiencing significant challenges. Key insights, conclusions and recommendations for future research are presented

Modern insulation materials for warming of walls

Biodiversity hotspots understandably attract considerable conservation attention. However, deserts are rarely viewed as conservation priority areas, due to their relatively low productivity, yet these systems are home to unique species, adapted to harsh and highly variable environments. While global attention has been focused on hotspots, the world's largest tropical desert, the Sahara, has suffered a catastrophic decline in megafauna. Of 14 large vertebrates that have historically occurred in the region, four are now extinct in the wild, including the iconic scimitar-horned oryx (Oryx dammah). The majority has disappeared from more than 90% of their Saharan range, including addax (Addax nasomaculatus), dama gazelle (Nanger dama) and Saharan cheetah (Acinonyx jubatus hecki) - all now on the brink of extinction. Greater conservation support and scientific attention for the region might have helped to avert these catastrophic declines. The Sahara serves as an example of a wider historical neglect of deserts and the human communities who depend on them. The scientific community can make an important contribution to conservation in deserts by establishing baseline information on biodiversity and developing new approaches to sustainable management of desert species and ecosystems. Such approaches must accommodate mobility of both people and wildlife so that they can use resources most efficiently in the face of low and unpredictable rainfall. This is needed to enable governments to deliver on their commitments to halt further degradation of deserts and to improve their status for both biodiversity conservation and human well-being. Only by so-doing will deserts be able to support resilient ecosystems and communities that are best able to adapt to climate change. © 2013 John Wiley & Sons Ltd