Sequential two electron photooxidation of t-amines: generation of a regiospecific iminium cation and its application in organic synthesis

PET activation of cyclic t-amines, utilizing 9, 10-dicyanonaphthalene (DCN) as light absorbing electron acceptor in aqueous acetonitrile solution, leads to the generation of iminium cation intermediate involving electron - proton - electron (E-P-E) transfer sequence. Iminium cation generation is found to be highly regiospecific and depends upon the kinetic acidity which is subject to the stereoelectronic factor of the α -C-H proton of the unymmetrical t-amines. Tetrahydro-1, 3-oxazines (6) are synthesized in complete regio-and stereoselective manner from the PET activation of the substrates of type 4. Nucleophilic alkylation of 6 by alkyl Grignard reagents provides cis- α, α'-dialkyl cyclic amines (8). Similarly, chiral perhydropyrido[2,1-b][1, 3, 4]-oxadiazinone (11) is synthesized as a precursor for the synthesis of optically active α-alkyl piperidines. Both enantiomers of hemlock alkaloid coniine (13) are also synthesized. Furthermore, to broaden the scope of these reactions, precursor 16 is designed for the synthesis of various α-amino acids and their N-alkyl derivatives

Design of a photosystem to harvest visible-light into electrons: photosensitised one electron redox reactions in organic synthesis

Based on synchronous oxidation-reduction processes, analogous to photosynthetic mechanistic paradigm, a photosystem utilising Ph3P or ascorbic acid as sacrificial electron donor has been developed to halvest electrons from visible light photons. The utility of such photosystem has been demonstrated by initiating various one-electron reductive -C-C-bo nd formation reactions. Biologically active PGE1, and C-Furanosides are synthesised employing this photosystem at a crucial step

Confer ment ence on International Agricultural Research for Develop Effects of Farmers' Perceptions on the Adoption of Modern Rice Varieties in Nepal

Abstract everal modern varieties of rice have been released in Nepal to raise the productivity, a major pies about 50 percent of the total area under food S staple crop. Farmers have adopted these varieties to varying degrees, especially in rainfed areas. This paper attempts to identify factors that affect the adoption of modern varieties of rice. Farmers considered suitability of rice varieties based on several characteristics. They were more concerned with biotic and abiotic stresses, which probably reflects the high incidence of these stresses in the rainfed condition. Modern varieties were superior over traditional varieties for many characteristics except in terms of taste. It is hypothesized that farmers' perceptions regarding varietal characteristics play a key role in explaining adoption behavior. This hypothesis was tested using farm-level data from rainfed areas of Nepal. An econometric model that includes farmers' perception variables was found to be superior in explaining adoption behavior than the ones that include only the usual farm and farmer related variables. Farmers' perceptions of the varietal characteristics such as pest resistance, drought tolerance and suitability for making special products were important in determining technology choices in the areas where current adoption rates are quite high. It was also found that the farms and farmers' specific variables such as education of the decision maker and his/her experience in rice farming, and availability of extension services have significant effect on adoption of modern varieties. Research approaches that incorporate farmers' preferences for various characteristics of rice in breeding programs and extension strategies that are geared towards providing accurate information for efficient revision of farmer perceptions are needed to raise the adoption rate. Background and Aim of the Study Rice is the staple food crop of Nepal. It occu crops of 3.2 million hectares and its contribution to the total food supply is more than 50 percent. This crop alone contributes to about 40 percent of the total calorie intake. In order to increase the productivity, modern varieties (MVs) of rice were introduced in late 1960s in Nepal. Overall, the spread of MVs and associated technologies is concentrated in pockets of favorable irrigated areas, with farmers choosing to follow largely traditional practices in less favorable rainfed areas. Although over 48 MVs have been released in Nepal, limited spread of MVs and their low productivity continue to remain major constraints to increasing the rice production in Nepal. Analysis of factors constraining the diffusion of MVs, especially in the dominant rainfed ecosystem of Nepal, is hence, an important area of research

Impact of Supplementary Nutrition on Undernourished Children In An Urban Area Of Meerut- A Longitudinal Study

Background: Infants and pre-school are most susceptible to undernutrition. Integrated Child Development Services is the programme focussing undernourished children by providing them supplementary nutrition. Aim& Objective: To study prevalence of undernutrition in 0-6 year old children and to study factors associated with it. To study impact of supplementary nutrition on undernourished children. Settings and Design: A longitudinal study. Methods and Material: The present longitudinal study was conducted in randomly selected Anganwadis of urban Meerut. Children found to be suffering from under nutrition were followed up at interval of six months to see the impact of supplementary nutrition provided to them at the anganwadi centre. A detailed history of relevant underlying factors responsible for causation of under nutrition were taken from mothers of these children. Statistical analysis used: chi square test was used to find out association between risk factors and undernutrition. Risk factor found statistically significant were further analysed using step wise multiple logistic regression analysis. The impact of supplementary nutrition was assessed using paired t test. Results: Iron folic acid supplementation during pregnancy, exclusive breast feeding in children, immunization and time of initiating complementary feed were found statistically significant on both chi-square and multiple logistic regression analysis. No impact of supplementary nutrition was found on anthropometric measurements of children. Conclusions: The main focus for fighting undernutrition in children (0-6 years) should be on preventing risk factors associated with mothers in antenatal period and during child rearing practice

Effects of Distal Mandibular Skeletal Injury on Temporomandibular Joint Soft Tissue without Bony Injury to the Joint: An Arthroscopic Screening Survey

Introduction: Trauma to the temporomandibular joint (TMJ) may be associated with injury to its associated soft tissues along with the bony condyle. However, it is often neglected that even in the absence of fracture of the mandibular condyle, there may be damage to the associated soft tissues of the joint. The routine radiographic study does not reveal the soft-tissue injury around the joint and its extent. Such injuries may progress to temporomandibular joint disorders (TMDs) in the future. Materials and Methods: A prospective study was conducted among 50 patients diagnosed with anterior mandibular fractures without condylar fracture. The patients were assessed for soft-tissue injury around the TMJ using an arthroscopic examination by a single qualified operator. Patients were evaluated clinically and arthroscopic examination was performed to examine the TMJ soft tissues at the time of surgery for facial fracture reduction under general anesthesia. Results: Among the 50 patients, n = 37 (74%) patients had severe injury to the soft tissues surrounding the TMJ. Majority of the patients had arthroscopic evidence of soft-tissue injury around the joint. Conclusion: From this study, we observe that patients with mandibular fracture without condylar involvement should be evaluated for TMJ soft-tissue injuries and subjected to long-term follow-up to prevent TMDs in the late postoperative period

Precipitation Structure in the Sierra Nevada of California During Winter

The influences of upper air characteristics along the coast of California upon the winter time precipitation in the Sierra Nevada region were investigated. Most precipitation episodes in the Sierra are associated with moist southwesterly winds and also tend to occur when the 700-mb temperature is close to -2 C. This favored wind direction and temperature signifies the equal importance of moisture transport and orographic lifting for maximum precipitation frequency. Making use of this observation, simple linear models were formulated to quantify the precipitation totals observed at different sites as a function of moisture transport. The skill of the model is least for daily precipitation and increases with time scale of aggregation. In terms of incremental gain, the skill of the model is optimal for an aggregation period of 5-7 days, which is also the duration of the most frequent precipitation events in the Sierra. This indicates that upper air moisture transport at can be used to make reasonable estimates of the precipitation totals for most frequent events in the Sierra region

Association of angiotensin-converting enzyme, methylene tetrahydrofolate reductase and paraoxonase gene polymorphism and coronary artery disease in an Indian population

Background: Coronary artery disease (CAD) and cancer remain the leading causes of death in most developed countries. Elucidating the genetic components that contribute to their pathogenesis is challenging. In this case-control association study, we examine the association of single nucleotide polymorphisms (SNPs) in paraoxonase 573 A/G genes, methylene tetrahydrofolate reductase (MTHFR) 677 C/T and angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism with CAD independently, as well as synergistically, in a north Indian population. Methods and results: Patients with at least 50% stenosis of at least one major coronary artery were classified as cases. The controls had no myocardial infarction. Polymerase chain reactions (PCR) followed by restriction fragment length polymorphism (RFLP) analyses were carried out to determine the SNPs. No significant association of the polymorphisms of the ACE or MTHFR genes with the risk of CAD was observed. However, the allele frequencies of the 573 A/G polymorphism of the paraoxonase gene differed significantly among cases and controls before and after controlling for confounding factors. The frequencies of AG vs AA genotypes and GG+AG vs AA genotypes also differed significantly in the two groups (p = 0.0002). The interaction of paraoxanase with both MTHFR and ACE independently showed significant positive associations Conclusions: The identification of ‘at risk’ individuals by genetic mapping of susceptible genes for effective control of other host factors will be a very effective and practical approach for prevention, as well as the development of improved therapy for patients. (Cardiol J 2011; 18, 4: 385–394