Ir/Sn dual-reagent catalysis towards highly selective alkylation of arenes and heteroarenes with benzyl alcohols

A catalytic combination of [Ir(COD)Cl]2SnCl4 efficiently promotes the reactions of arenes and heteroarenes with 1°/2°/3° benzyl alcohols as the alkylating agents to afford the corresponding diarylmethane and triarylmethane derivatives in high yields. The scope and limitation of the reaction with respect to catalyst and substrates variation has been studied in detail

RECENT NANOCOCHLEATE DRUG DELIVERY SYSTEM FOR CANCER TREATMENT: A REVIEW

Nanocochleates are at the forefront of the fast-growing nanotechnology sector in the delivery of drugs for cancer. This nanotechnology is the use of the cationic and anionic encapsulated drug that has poor oral bioavailability. Nanocochleate is a lipid-based drug delivery in the liposomal vesicles that is converted by calcium divalent cation into nanocochleate. Nanocochleates technology use encapsulations of the anticancer agent, which have low solubility, oral bioavailability and low permeability. This paper shows and provides an overview of the benefits of nanocochleates, drug delivery mechanism, choice of prevalent components (Phospholipids and Cations), various ways of producing nanocochleates and nanocochleate stability. Nanocochleates have far fewer constraints than other traditional carriers. To characterize nanocochleates, the suitable analytical methods are required. Therefore, in the therapy of cancer, nanocochleate becomes commonly applied and more prospective drug delivery system

Performance of engineering parameters of a water treatment plant: a case study

Kolkata Metropolitan Development Authority (KMDA), constructed a 30 mgd. capacity water treatment plant at Kamarhati, a municipal town, which is nearly 15 km. away from Kolkata. The plant started functioning in April, 1993. The plant consisted of conventional clariflocculators and rapid gravity filters. The source of water is river Hoogly; The plant supplies treated surface water to six adjoining municipalities catering the need of nearly 1.3 million population. In order to operate an efficient treatment system to achieve water of desirable quality, environmental safety and amenability for sustenance, a study was conducted throughout a year to identify and evaluate the performance of engineering parameters of treatment units such as clariflocculators, filter bed etc. A few technical findings are discussed in this paper on the efficiency of clarifloculators. The filter bed performance is assessed in terms of filter media, size distribution. Samples of backwash water is also collected for estimation of selective physico-chemical parameters

Rectal bleeding in children

Rectal bleeding is quite common in children. Often the bleeding is self-limiting. Rectal polyps are very important cause of rectal bleeding. Infections like shigellosis are important causes and should be kept in mind for differential diagnosis

Neonatal hypoglycemia revisited: Incidence and clinical profile in a tertiary center hospital of Tripura

Introduction: Hypoglycemia is a common but preventable metabolic abnormality in neonates associated with long-term sequelae. Controversies still exist about its definition, screening methodology, management, and outcome making it a subject for further exploration. Objectives: The study was taken up to find out the proportion of neonate developing hypoglycemia in the neonatal intensive care unit (NICU) and to study the clinical profile of hypoglycemia in neonates. Materials and Methods: All intramural and extramural neonates admitted in the NICU within 2 h of delivery were included in this study. They were screened for hypoglycemia using Accutrend-alpha glucometer. Results along with all neonatal and maternal variables were recorded and analyzed using the SPSS version 15.0. Results: The current study shows the prevalence of hypoglycemia as 32.2%. Proportion of hypoglycemia was more in small for gestational age, large for gestational age neonates, and neonates with prematurity, birth asphyxia, and maternal diabetes mellitus. Besides, hypoglycemia occurred more commonly within 24 h of life. Lethargy, convulsion, apnea, and jitteriness were common presenting symptom. Conclusion: The present study shows despite advances in obstetrical practices and increase in institutional deliveries over years, neonatal hypoglycemia continues to occur with almost same frequency along with the same maternal and neonatal variables

DNA repair and recombination in higher plants: insights from comparative genomics of arabidopsis and rice

<p>Abstract</p> <p>Background</p> <p>The DNA repair and recombination (DRR) proteins protect organisms against genetic damage, caused by environmental agents and other genotoxic agents, by removal of DNA lesions or helping to abide them.</p> <p>Results</p> <p>We identified genes potentially involved in DRR mechanisms in <it>Arabidopsis </it>and rice using similarity searches and conserved domain analysis against proteins known to be involved in DRR in human, yeast and <it>E. coli</it>. As expected, many of DRR genes are very similar to those found in other eukaryotes. Beside these eukaryotes specific genes, several prokaryotes specific genes were also found to be well conserved in plants. In <it>Arabidopsis</it>, several functionally important DRR gene duplications are present, which do not occur in rice. Among DRR proteins, we found that proteins belonging to the nucleotide excision repair pathway were relatively more conserved than proteins needed for the other DRR pathways. Sub-cellular localization studies of DRR gene suggests that these proteins are mostly reside in nucleus while gene drain in between nucleus and cell organelles were also found in some cases.</p> <p>Conclusions</p> <p>The similarities and dissimilarities in between plants and other organisms' DRR pathways are discussed. The observed differences broaden our knowledge about DRR in the plants world, and raises the potential question of whether differentiated functions have evolved in some cases. These results, altogether, provide a useful framework for further experimental studies in these organisms.</p

Dopamine Regulates Angiogenesis in Normal Dermal Wound Tissues

Cutaneous wound healing is a normal physiological process and comprises different phases. Among these phases, angiogenesis or new blood vessel formation in wound tissue plays an important role. Skin is richly supplied by sympathetic nerves and evidences indicate the significant role of the sympathetic nervous system in cutaneous wound healing. Dopamine (DA) is an important catecholamine neurotransmitter released by the sympathetic nerve endings and recent studies have demonstrated the potent anti-angiogenic action of DA, which is mediated through its D2 DA receptors. We therefore postulate that this endogenous catecholamine neurotransmitter may have a role in the neovascularization of dermal wound tissues and subsequently in the process of wound healing. In the present study, the therapeutic efficacy of D2 DA receptor antagonist has been investigated for faster wound healing in a murine model of full thickness dermal wound. Our results indicate that treatment with specific D2 DA receptor antagonist significantly expedites the process of full thickness normal dermal wound healing in mice by inducing angiogenesis in wound tissues. The underlined mechanisms have been attributed to the up-regulation of homeobox transcription factor HoxD3 and its target α5β1 integrin, which play a pivotal role in wound angiogenesis. Since D2 DA receptor antagonists are already in clinical use for other disorders, these results have significant translational value from the bench to the bedside for efficient wound management along with other conventional treatment modalities

Ir/Sn dual reagent catalysis for the alkylation of arenes with benzyl alcohols: kinetic evidence for an electrophilic pathway and a guide towards electronic tuning of catalyst efficiency

Presented herein is a detailed account of the [Ir(COD)(μ-Cl)]2/SnCl4 dual reagent catalyzed alkylation of arene/heteroarene with benzyl alcohols [J. Choudhury, S. Podder, S. Roy, J. Am. Chem. Soc. 127 (2005) 6162]. A high-valent heterobimetallic complex namely [IrIII(COD)(μ-Cl)(SnCl3)Cl]2 (isolated from [Ir(COD)(μ-Cl)]2 and SnCl4) could also promote the alkylation. A working model on substrate binding, activation and coupling across Ir/Sn catalyst is proposed considering the hard-soft nature of the two metals (Ir and Sn) and the organic substrates (arene and alcohol). The "tin-alcohol" hard-hard interaction is indicated by the alkylation rate for PhCH2-Y which varied with the HSAB donor strength of Y in the order OH &gt; OAc &gt; OMe &gt; OC(O)H &gt; Cl. Hammett studies with respect to arene and alcohol indicate an electrophilic mechanism. A small secondary kinetic isotope effect ruled out a C-H activation pathway. Competitive and non-competitive rate studies (isomer distribution and kT/kB ratio) showed a similarity with Friedel-Crafts like kinetics. Temperature dependent kinetics showed that the reaction is characterized by a positive enthalpy of activation, and small negative entropy of activation. The stereoelectronic influence of the two metal centers on the catalyst efficiency is also studied. It is shown that the coordinated ligand at the iridium center and the Lewis acidity at the tin center control the efficiency of the Ir/Sn catalysts towards aromatic alkylation