Non-enzymatic electrochemical detection of creatinine based on a glassy carbon electrode modified with a Pd/Cu2O decorated polypyrrole (PPy) nanocomposite: an analytical approach.

The major constraints of standard enzymatic biosensors are poor long-term storage stability and high cost. Hence, there is extensive research towards fabrication of reliable enzymeless biosensors based on nanomaterials. In this paper, we present the development of an enzymeless electrochemical biosensor for highly precise detection of creatinine. This involves the use of a simple yet effective alternative to the commonly utilized Pd/Cu2O/PPy nanocomposite, which was characterized by different analytical methods. The present electrochemical sensor provides a wide detection range (0.1 to 150 µM), low detection limit (0.05 µM) and high sensitivity (0.207 µA), and is capable of detecting the creatinine level in human urine samples, which are inexpensive. The results are reproducible, and the sensor is stable. The sensor demonstrates good electrocatalytic activity and selectivity towards the detection of creatinine in the presence of various other similar biological entities. When compared to other existing counterparts, the electrocatalytic behaviour of the present sensor is comparable, if not better. So, the present electrochemical sensor for creatinine might be employed as a long-term diagnostic alternative.

Ultra-narrowband polarization insensitive transmission filter using a coupled dielectric-metal metasurface.

A coupled dielectric-metal metasurface (CDMM) filter consisting of amorphous silicon (a-Si) rings and subwavelength holes in Au layer separated by a SiO2 layer is presented. The design parameters of the CDMM filter is numerically optimized to have a polarization independent peak transmittance of 0.55 at 1540 nm with a Full Width at Half Maximum (FWHM) of 10 nm. The filter also has a 100 nm quiet zone with ∼10-2 transmittance. A radiating two-oscillator model reveals the fundamental resonances in the filter which interfere to produce the electromagnetically induced transparency (EIT) like effect. Multipole expansion of the currents in the structure validates the fundamental resonances predicted by the two-oscillator model. The presented CDMM filter is robust to artifacts in device fabrication and has performances comparable to a conventional Fabry-Pérot filter. However, it is easier to be integrated in image sensors as the transmittance peak can be tuned by only changing the periodicity resulting in a planar structure with a fixed height.

In vitro anti-acne activity of phytoactives from the stem bark of Artocarpus hirsutus Lam. and characterisation of pyranocycloartobiloxanthone A as a mixture of two anomers.

This study is aimed to isolate the phytoactives from the stem bark of Artocarpus hirsutus and evaluate their in vitro anti-acne activity. The ethanolic stem bark extract of A. hirsutus provided two major phytoactive constituents: (i) pyranocycloartobiloxanthone A, (1) and (ii) Artonine E, (2) whose structures were determined by NMR and MS spectroscopic analysis. The present study is the first to report compound 1 as a mixture of two anomers (α and ß), approximately 70:30 ratio. Both compounds 1 and 2 were isolated for the first time from this plant. In vitro anti-acne activity of compounds 1 and 2 were evaluated by agar well diffusion method and the minimum inhibition was determined by broth micro dilution method. The result of anti-microbial activity (MIC = 2.0 µg/mL each) is comparable to antibiotic, Clindamycin (MIC = 0.03 µg/mL) and clearly demonstrate their potential as anti-acne agents.

Molecular farming of fluorescent virus-based nanoparticles for optical imaging in plants, human cells and mouse models.

The application of plant virus-derived nanostructures in materials science, biomedical research and engineering has recently been promoted by the development of fluorescence-labeled viruses for optical imaging in tissue culture and preclinical animal models. Most studies reported thus far have focused on the application of viruses that have been chemically modified with organic dyes. In this investigation, we sought to develop and study genetically-engineered virus-based biomaterials that incorporate green or red fluorescent proteins. The genetic introduction of such imaging moieties is advantageous because post-harvest modifications are not required, thus minimizing the number of manufacturing steps and maximizing the yields of each fluorescent probe. Specifically, we engineered the filamentous plant virus Potato virus X (PVX) to display green fluorescent protein (GFP) or mCherry as N-terminal coat protein (CP) fusions, producing a 1 : 3 fusion protein to CP ratio. The infection of Nicotiana benthamiana plants with the recombinant GFP-PVX and mCherry-PVX particles was documented by fluorescence imaging, structural analysis and genetic characterization to determine the stability of the chimeras and optimize the molecular farming protocols. We also demonstrated the application of fluorescent mCherry-PVX filaments as probes for optical imaging in human cancer cells and a preclinical mouse model. Cell viability assays and histological analysis following the administration of mCherry-PVX indicated the biocompatibility and rapid tissue clearance of the particles. Such particles could therefore be functionalized with additional cancer-specific detection ligands to provide tools for molecular imaging, allowing the investigation of molecular signatures, disease progression/recurrence and the efficacy of novel therapies.

Influence of dose of inocula on outcome of clinical disease in highly pathogenic avian influenza (H5N1) infections--an experimental study.

Twelve-week-old Vanaraja (an Indian native dual purpose breed) chickens were inoculated intranasally with different doses (100, 1000, and 10,000 mean embryo infective dose [EID50]) of H5N1 virus, and the clinical disease and pathologic changes were compared. Although the overall severity of clinical signs was more severe in the 100 EID50 group, the progression of the clinical disease was slower with delayed onset of mortality when compared with the other two groups. The mean death time of the 100 EID50 group (4.57 days) differed significantly from that of the 10,000 EID50 group (3.60 days) and from that of the 1000 EID50 group (3.33 days). Similarly, overall severity of gross lesions was expressed more in the 100 EID50 group. The histopathologic lesions were of a more hemorrhagic and necrotic nature in the 100 EID50 group, histopathologic lesions were of an inflammatory/proliferative nature in the 1000 EID50 group, and a tendency for intravascular coagulopathy was observed in the 10,000 EID50 group. These differences may be assigned to the influence of dose in the outcome of disease.

Agenesis of lung - a report of two cases.

Agenesis of lung is a rare congenital disorder. We are reporting varied degree of pulmonary agenesis in two adult patients.

Regio- and stereoselectivity of captodative olefins in 1,3-dipolar cycloadditions. A DFT/HSAB theory rationale for the observed regiochemistry of nitrones.

Captodative olefins 1-acetylvinyl carboxylates proved to be highly regioselective dipolarophiles in 1,3-dipolar cycloadditon to propionitrile oxide, arylphenylnitrile imines, diazoalkanes, and nitrones to yield the corresponding 5-substituted heterocycles. The addition of the latter was also stereoselective, being slightly susceptible to steric demand of the carboxylate substituent in the olefin. All atempts to cleave the isoxazolidine N-O bond under reductive conditions failed, providing diverse products with side-group reduction. FMO theory was unsuccessful to explain the regioselectivity observed with nitrones, since the opposite orientation was predicted. The recently formulated DFT/HSAB theoretical model was able to rationalize this regioselectivity, identifying the nucleophilic and electrophilic atoms involved in the process via calculation of interaction energies, suggesting the specific direction of the electronic process at each of the reaction sites.

Reductive dechlorination of the nitrogen heterocyclic herbicide picloram.

The anaerobic biodegradation of picloram (3,5,6-trichloro-4-amino-2-pyridinecarboxylic acid) in freshwater sediment was favored under methanogenic conditions but not when sulfate or nitrate was available as a terminal electron acceptor. Under the former conditions, more than 85% of the parent substrate (340 muM) was removed from nonsterile incubations in 30 days, following a 50-day acclimation period. Concomitant with substrate decay, an intermediate transiently accumulated in the sediment slurries. By liquid chromatography-mass spectrometry, the intermediate was identified as an isomer of dichloro-4-amino-2-pyridinecarboxylic acid. Proton nuclear magnetic resonance evidence suggested that a chlorine was reductively removed from the parent substrate at the position meta to the nitrogen heteroatom. Upon continued incubation, the dechlorinated product was transformed into an unidentified compound which accumulated and resisted further decay. The addition of sulfate or bromoethanesulfonic acid to sediment slurries inhibited picloram dehalogenation, but molybdate reversed the inhibitory effect of sulfate on pesticide metabolism. These findings help clarify the fate of a halogenated nitrogen heterocyclic herbicide in anaerobic environments.