Toward an Alternative Intrinsic Probe for Spectroscopic Characterization of a Protein

The intrinsic fluorescent amino acid tryptophan is the unanimous choice for the spectroscopic investigation of proteins. However, several complicacies in the interpretation of tryptophan fluorescence in a protein are inevitable and an alternative intrinsic protein probe is a longstanding demand. In this contribution, we report an electron-transfer reaction in a human transporter protein (HSA) cavity which causes the tryptophan residue (Trp214) to undergo chemical modification to form one of its metabolites kynurenine (Kyn214). Structural integrity upon modification of the native protein is confirmed by dynamic light scattering (DLS) as well as near and far circular dichroism (CD) spectroscopy. Femtosecond-resolved fluorescence transients of the modified protein describe the dynamics of solvent molecules in the protein cavity in both the native and denatured states. In order to establish general use of the probe, we have studied the dipolar interaction of Kyn214 with a surface-bound ligand (crystal violet, CV) of the protein. By using the sensitivity of FRET, we have determined the distance between Kyn214 (donor) and CV (acceptor). Our study is an attempt to explore an alternative intrinsic fluorescence probe for the spectroscopic investigation of a protein. In order to establish the efficacy of the modification technique we have converted the tryptophan residues of other proteins (bovine serum albumin, chymotrypsin and subtilisin Carlsberg) to kynurenine and confirmed their structural integrity. We have also shown that catalytic activity of the enzymes remains intact upon the modification

Interaction of an Antituberculosis Drug with a Nanoscopic Macromolecular Assembly: Temperature-Dependent Förster Resonance Energy Transfer Studies on Rifampicin in an Anionic Sodium Dodecyl Sulfate Micelle

In this contribution, we report studies on the nature of binding of a potent antituberculosis drug, Rifampicin (RF) with a model drug delivery system, sodium dodecyl sulfate (SDS) micelle. Temperature dependent dynamic light scattering (DLS), conductometry, and circular dichroism (CD) spectroscopy have been employed to study the binding interaction of the drug with the micelle. The absorption spectrum of the drug RF in the visible region has been employed to study Förster resonance energy transfer (FRET) from another fluorescent drug Hoechst 33258 (H33258), bound to the micelle. Picosecond-resolved FRET studies at room temperature confirm the simultaneous binding of the two drugs to the micelle and the distance between the donor−acceptor pair is found to be 34 Å. The temperature dependent FRET study also confirms that the location and efficiency of drug binding to the micelle changes significantly at the elevated temperature. The energy transfer efficiency of the donor H33258, as measured from time-resolved studies, decreases significantly from 76% at 20 °C to 60% at 55 °C. This reveals detachment of some amount of the drug molecules from the micelles and increased donor−acceptor distance at elevated temperatures. The estimated donor−acceptor distance increases from a value of 33 Å at 20 °C to 37 Å at 55 °C. The picosecond resolved FRET studies on a synthesized DNA bound H33258 in RF solution have been performed to explore the interaction between the two. Our studies are expected to find relevance in the exploration of a potential vehicle for the vital drug rifampicin

A HYBRID CLOUD APPROACH FOR SECURE APPROVED DEDUPLICATION

Information Deduplication is one of imperative information pressure systems for wiping out copy duplicates of rehashing information, and has been generally utilized as a part of distributed storage to decrease the measure of storage room and spare data transmission. To secure the secrecy of touchy information while supporting Deduplication, the concurrent encryption system has been proposed to scramble the information before outsourcing. To better ensure information security, this methodology makes the main endeavor to formally address the issue of approved information Deduplication. Unique in relation to customary Deduplication frameworks, the differential benefits of clients are further considered in copy check other than the information itself. It likewise exhibit a few new Deduplication developments supporting approved copy check in a half and half cloud engineering. Security examination exhibits that our plan is secure as far as the definitions indicated in the proposed security model. As a proof of idea, we actualize a model of proposed approved copy check plan and direct testbed tests utilizing model. It demonstrates that proposed approved copy check plan brings about insignificant overhead contrasted with typical operations

Photoselective excited state dynamics in ZnO–Au nanocomposites and their implications in photocatalysis and dye-sensitized solar cells

Improving the performance of photoactive solid-state devices begins with systematic studies of the metal–semiconductor nanocomposites (NCs) upon which such devices are based. Here, we report the photo-dependent excitonic mechanism and the charge migration kinetics in a colloidal ZnO–Au NC system. By using a picosecond-resolved Förster resonance energy transfer (FRET) technique, we have demonstrated that excited ZnO nanoparticles (NPs) resonantly transfer visible optical radiation to the Au NPs, and the quenching of defect-mediated visible emission depends solely on the excitation level of the semiconductor. The role of the gold layer in promoting photolytic charge transfer, the activity of which is dependent upon the degree of excitation, was probed using methylene blue (MB) reduction at the semiconductor interface. Incident photon-to-current efficiency measurements show improved charge injection from a sensitizing dye to a semiconductor electrode in the presence of gold in the visible region. Furthermore, the short-circuit current density and the energy conversion efficiency of the ZnO–Au NP based dye-sensitized solar cell (DSSC) are much higher than those of a DSSC comprised of only ZnO NP. Our results represent a new paradigm for understanding the mechanism of defect-state passivation and photolytic activity of the metal component in metal–semiconductor nanocomposite systems

Giant adrenal myelolipoma - clinical spectrum and management: a single centre experience

Background: Adrenal myelolipomas are rare benign tumor composed of mature adipocytes and normal haematopoetic cells. Giant adrenal myelolipomas are rare clinical entities. Most of them are symptomatic. We present 15 such cases, their clinical spectrum and management.Methods: Retrospective analysis of giant adrenal myelolipomas from a tertiary level institute. Initial diagnosis was made by computed tomography.Results: Mean age of patient was 45.6±11 years with slightly higher female preponderance. All patients were overweight with predominantly left sided adrenal myelolipoma. Majority of them (93%) were symptomatic and presented with abdominal pain, anemia or fever. Mean size of the mass on imaging was 14 cm±6 cm, with largest lesion measuring 26 cm.Conclusions: The article highlights the varying clinical presentations including rare emergency presentations of giant adrenal myelolipomas. A brief literature review is also presented

Ultrafast dynamics of excitons in semiconductor quantum dots on a plasmonically active nano-structured silver film

The excited state dynamics of core-shell type semiconductor quantum dots (QDs) of various sizes in close contact with a plasmonically active silver thin film has been demonstrated by using picosecond resolved fluorescence spectroscopy. The non-radiative energy transfer from the QDs to the metal surface is found to be of Föster resonance energy transfer (FRET) type rather than the widely expected nano-surface energy transfer (NSET) type. The slower rate of energy transfer processes compared to that of the electron transfer from the excited QDs to an organic molecule benzoquinone reveals an insignificant possibility of charge migration from the QDs to the metallic film

Functionalization of manganite nanoparticles and their interaction with biologically relevant small ligands: picosecond time-resolved FRET studies

We report molecular functionalization of the promising manganite nanoparticles La0.67Sr0.33MnO3 (LSMO) for their solubilization in aqueous environments. The functionalization of individual NPs with the biocompatible citrate ligand, as confirmed by Fourier transform infrared (FTIR) spectroscopy, reveals that citrates are covalently attached to the surface of the NPs. UV-VIS spectroscopic studies on the citrate functionalized NPs reveals an optical band in the visible region. Uniform size selectivity (2.6 nm) of the functionalization process is confirmed from high resolution transmission electron microscope (HRTEM). In the present study we have used the optical band of the functionalized NPs to monitor their interaction with other biologically important ligands. Forster resonance energy transfer (FRET) of a covalently attached probe 4-nitrophenylanthranilate (NPA) with the capped NPs confirm the attachment of the NPA ligands to the surface functional group (-OH) of the citrate ligand. The FRET of a DNA base mimic, 2-aminopurine (2AP), with the NPs confirms the surface adsorption of 2AP. Our study may find relevance in the study of the interaction of individual manganite NPs with drug/ligand molecules

TARGETED THERAPEUTIC DELIVERY: SUCCESS THROUGH MAGNETIC MICROCARRIERS

There has been keen interest in the development of a targeted therapeutic delivery system. Targeted therapeutic delivery system aims to target the therapeutics to the site of action. A number of targeted therapeutic delivery system has been studied for targeting of various drugs but researchers have shown keen interest in magnetic targeting now a day. These include magnetic microspheres, magnetic liposome, magnetic nanoparticles, magnetic resealed erythrocytes, magnetic emulsion etc. Magnetic microspheres involve applying an external magnetic field to capture drug-loaded magnetic carriers in a targeted site. Magnetic therapeutic targeting is a promising method to increase the delivery of therapeutic agents to tumor cells while reducing side effects.  Magnetic microspheres & molecular magnetic labels have been used for great number of application in various areas of biosciences, targeted drug delivery, diagnosis and in immunoassay. Much has been investigated and much more are to be investigated for the use of principle of magnetism in targeting of therapeutics to the various organs. Thus present review paper will discuss about mechanism of magnetic targeted therapeutics delivery, magnetic carriers, and application of magnetic microspheres in targeted delivery of therapeutics

Dynamics of light harvesting in ZnO nanoparticles

We have explored light harvesting of the complex of ZnO nanoparticles with the biological probe Oxazine 1 in the near-infrared region using picosecond-time-resolved fluorescence decay studies. We have used ZnO nanoparticles and Oxazine 1 as a model donor and acceptor, respectively, to explore the efficacy of the Förster resonance energy transfer (FRET) in the nanoparticle-dye system. It has been shown that FRET from the states localized near the surface and those in the bulk of the ZnO nanoparticles can be resolved by measuring the resonance efficiency for various wavelengths of the emission spectrum. It has been observed that the states located near the surface for the nanoparticles (contributing to visible emission at λ≈550 nm) can contribute to very high efficiency (>90%) FRET. The efficiency of light harvesting dynamics of the ZnO nanorods has also been explored in this study and they were found to have much less efficiency (∼40%) for energy transfer compared to the nanoparticles. The possibility of an electron transfer reaction has been ruled out from the picosecond-resolved fluorescence decay of the acceptor dye at the ZnO surface

Traumatic Bilateral Pars Fracture with Grade-I Spondylolisthesis Treated by Transforaminal (Trans Kambian) Endo Fusion under Epidural Analgesia: A Special Case Report

Traumatic spine injuries are common in young and adult population with worlds incidence estimated annual rate in 10.4–130.6 cases per million. We are presenting a case of traumatic bilateral pars fracture with Grade-I spondylolisthesis treated by Endoscopic Transforaminal (Trans Kambian) spine fusion, under epidural analgesia and neuromonitoring. To the best of our knowledge this is a unique scenario reported for the first time in literature. Lumbar fusion although considered as the gold standard for the degenerative spine disease and Spondylolisthesis, Endoscopic Transforaminal (Trans Kambian) lumbar fusion popularly known as Endofusion/Endo-TLIF (Transforaminal lumbar interbody fusion) is a recent and effective minimally invasive option for certain cases. A 30-year male presented with severe low back pain and decreased sensations over dorsum of right foot after a fall of heavy metal pipe on his lower back. (VAS score 9/10). After thorough preop evaluation patient underwent Endoscopic Transforaminal (Trans Kambian) lumbar discectomy and fusion under epidural analgesia, with visualized endplate preparation. Specially designed Titanium Endo-bullet cage was inserted after percutaneous pedicle screw placement under neuromonitoring. Complete reduction of listhesis was achieved with near total relief in pain. Endoscopic TLIF ensures minimal tissue retraction and minimal alteration of the normal anatomy aiding in faster recovery and minimal blood loss. Patient was mobilized and discharged within 24 hours of surgery. We suggest Endo fusion is a safe and effective day care procedure for cases with traumatic bilateral pars fractures