TRANES analysis of the fluorescence of nile red in organized molecular assemblies confirms emission from two species

Time-resolved area normalized emission spectroscopy (TRANES) is a new method for the analysis of fluorescence of dyes in complex chemical and biological systems (A S R Koti, M M G Krishna and N Periasamy, 2001,J. Phys. Chem. 105, 1767). The model-free method extends the power of time-resolved emission spectroscopy (TRES) analysis and removes the ambiguity in the interpretation when the emission spectrum is time-dependent. Observation of an isoemissive point in TRANES analysis of fluorescence is an unambiguous indication for the presence of two emissive species in the sample. The isoemissive point occurs at a wavelength where the ratio of the radiative rates of the two species is equal to the ratio of their total radiative rates. The polarity-sensitive nile red dye shows time-dependent emission spectra in the organized bilayer assemblies of TX micelle and bilayer egg-phosphotidylcholine (egg-PC) membrane. Time-dependent spectra in complex systems support many important models (solvation model and heterogeneity in the ground and/or excited state). TRANES analysis shows that the fluorescence emission of nile red in TX micelle and egg-PC membrane is due to two emissive species solubilized in different sites

Time resolved area normalized emission spectroscopy (TRANES) of DMABN confirms emission from two states

4-N, N-Dimethylaminobenzonitrile (DMABN) is a simple molecule which is extensively studied to understand the excited state kinetics and the origin of time dependent fluorescence in several organic solvents. We use a recently described method, time resolved area normalized emission spectroscopy (TRANES), for the analysis of wavelength dependent fluorescence of DMABN in acetonitrile and 1,4-dioxane. An isoemissive point was observed in the TRANES spectra, which confirms that there are only two emissive species A∗ and B∗:A→A∗⇔B∗

Solvent exchange in excited-state relaxation in mixed solvents

The fluorescence of styrylthiazoloquinoxaline (STQ) in the solvent mixture methanol and dichloromethane (DCM) and 2-octanol have many common characteristics: biexponential fluorescence decay, wavelength-dependent amplitudes, a negative amplitude for the short-lifetime component at long emission wavelengths, and a time-dependent red shift of the emission spectrum. In octanol, the fluorescence lifetime decreases with increasing temperature, whereas the lifetime increases with temperature in the methanol/DCM mixture. The fluorescence characteristics in 2-octanol (η=7.29 cP) are readily explained by the conventional model of excited-state relaxation kinetics by solvent reorientation. This model is not applicable for low-viscosity (η=0.455 cP) solvent mixtures. A model of excited-state relaxation kinetics involving solvent exchange (versus solvent reorientation in pure solvents) in the excited state is proposed for the solvent mixture. The model assumes that the solvent compositions around the solute are different in the ground and excited states and the solvent composition is temperature dependent

A Rare Case of Situs Inversus with Mesocardia

A ten year old male child having congenital heart disease admitted with recurrent history of respiratory infection. ECHO cardioraphy showed Mesocardia, congenitally corrected TGA, bidirectional VSD and severe pulmonary valve stenosis.On sonographic evaluation showed intra-abdominal mirror imaging of all the solid organs and vessels which was suggestive of a rare presentation of Sinus inverses with Mesocardia. Corrective surgery as pulmonary valve balloon dilation or valvuloplasty and vestricular septal repair has to be done to the child for better morbidity and reducing the mortality risk. This anomaly complicates the diagnosis and management of acute abdominal conditions like appendicitis, diverticulitis and biliary coli

NMR studies on truncated sequences of human telomeric DNA: observation of a novel A-tetrad

The structure of the telomeric DNA has been a subject of extensive investigation in recent years due to the realization that it has important functional roles to play in vivo and the observations that truncated telomeric sequences exhibit a great variety of 3D structures in aqueous solutions. In this context, we describe here NMR structural studies on two truncated human telomeric DNA sequences, d-AG3T and d-TAG3T in solutions containing K+ ions. The G3 stretches in both the oligonucleotides were seen to form parallel-stranded quadruplexes. However, the AG3 segment as a whole, had different structural characteristics. The structure of d-AG3T revealed the formation of a novel A-tetrad, which was not seen in d-TAG3T. The A's in the tetrad had syn glycosidic conformation as opposed to the anti conformation of the G's in the G-tetrads. The A-tetrad stacked well over the adjacent G-tetrad and the twist angle at this step was smaller in d-AG3T than in d-TAG3T. These observations are expected to be significant from the point of view of structural diversity and recognition in telomeres

Can We Do Away With PTBD?

Percutaneous Transhepatic Biliary Drainage (PTBD) is performed in surgical jaundice to decompress the biliary tree and improve hepatic functions. However, the risk of sepsis is high in these patients due to immunosuppression and surgical outcome remains poor. This raises a question—can we do away with PTBD? To answer this query a study was carried out in 4 groups of patients bearing in mind the high incidence of sepsis and our earlier studies, which have demonstrated immunotherapeutic potential of Tinospora cordifolia (TC): (A) those undergoing surgery without PTBD (n = 14), (B) those undergoing surgery after PTBD (n = 13). The mortality was 57.14% in Group A as compared to 61.54% in Group B. Serial estimations of bilirubin levels carried out during the course of drainage (3 Wks) revealed a gradual and significant decrease from 12.52 ± 8.3 mg% to 5.85 ± 3.0 mg%. Antipyrine half-life did not change significantly (18.35 ± 4.2 hrs compared to basal values 21.96 ± 3.78 hrs). The phagocytic and intracellular killing (ICK) capacities of PMN remained suppressed (Basal: 22.13 ± 3.68% phago, and 19.1 ± 4.49% ICK; Post drainage: 20 ± 8.48% Phago and 11.15 ± 3.05% ICK). Thus PTBD did not improve the metabolic capacity ofthe liver and mortality was higher due to sepsis. Group (C) patientg received TC during PTBD (n = 16) and Group (D) patients received TC without PTBD (n = 14). A significant improvement in PMN functions occurred by 3 weeks in both groups (30.29 ± 4.68% phago, 30 ± 4.84% ICK in Group C and 30.4 ± 2.99% phago, 27.15 ± 6.19% ICK in Group D). The mortality in Groups C and D was 25% and 14.2% respectively during the preoperative period. There was no mortality after surgery. It appears from this study that host defenses as reflected by PMN functions play an important role in influencing prognosis. Further decompression of the biliary tree by PTBD seems unwarranted

An Efficient Information Extraction Mechanism with Page Ranking and a Classification Strategy based on Similarity Learning of Web Text Documents

Users have recently had more access to information thanks to the growth of the www information system. In these situations, search engines have developed into an essential tool for consumers to find information in a big space. The difficulty of handling this wealth of knowledge grows more difficult every day. Although search engines are crucial for information gathering, many of the results they offer are not required by the user because they are ranked according on user string matches. As a result, there were semantic disparities between the terms used in the user inquiry and the importance of catch phrases in the results. The problem of grouping relevant information into categories of related topics hasn't been solved. A Ranking Based Similarity Learning Approach and SVM based classification frame work of web text to estimate the semantic comparison between words to improve extraction of information is proposed in the work. The results of the experiment suggest improvisation in order to obtain better results by retrieving more relevant results

Media Optimization for Depolymerization of Alginate by Pseudomonas aeruginosa AG LSL-11

ABSTRACT An agar degrading bacterium Pseudomonas aeruginosa AG LSL-11 was acclimatized to alginate for the production of alginase. Production parameters such as pH, temperature, influence of simple carbohydrates and nitrogen sources, and effect of NaCl on growth and alginase production were carried out. Maximum growth was observed at pH 9.0 and 35 °C, while alginase was produced optimally at pH 9.0 and 30 °C. The alginase produced by Pseudomonas aeruginosa AG LSL-11 was inducible by alginate, and repressed by other simple sugar when supplemented along with alginate in the medium. The bacterium did not require NaCl for growth and production of alginase. The activity staining of partially purified culture supernatant after native PAGE revealed the presence of a single alginase