Evaluation of AgNCs@PEI and their integrated hydrogel for colorimetric and fluorometric detection of ascorbic acid.

A dual-mode colorimetric and fluorometric sensor based on water soluble silver nanoclusters (AgNCs@PEI) is developed for quantitative and visual detection of ascorbic acid (Asc A). The detection method relies on the Asc A induced aggregation of AgNCs@PEI, which resulted in fluorecsence quenching of the sensor. The clusters exhibited a unique combination of static and collisional quenching with a wide range of dynamic detection (1-105 µM) Linear relationship was observed in the concentration range 102-103 µM using fluorescence and 0.2 × 102-5 × 103 µM using absorbance spectroscopy with respective detection limits of 10.65 µM and 2.49 µM. The corresponding colorimetric and fluorometric changes can be easily monitored by the naked eye with a visual detection limit of 103 µM. AgNCs@PEI were further integrated within a hydrogel for developing a solid-state visual detection platform. Notably, the sensing response of the clusters towards Asc A remained unaltered even after hydrogel integration. Additionally, digital image analysis was adopted, which improved the sensitivity of instrument-free fluorescence detection of Asc A. Analysis by the developed sensor showed excellent recovery percentages of Asc A in spiked urine samples, which further underscores the practical applicability of the sensor.

Procedural sedation in children for fractionated radiation treatment: Intranasal dexmedetomidine versus oral midazolam and ketamine.

Background and Aims: Sedation in paediatric cancer for fractionated radiation treatment (RT) is unique as the child has to be still for accurate delivery of RT, monitoring of the child is from a remote location and sedation is repeated for multiple sessions of RT. The present study was undertaken to compare the efficacy of intranasal dexmedetomidine with oral midazolam and ketamine combination for repeated sedation during fractionated RT in paediatric oncology. Methods: Ninety children aged between 3-6 years, planned for 21 fractions of RT, were randomised to receive intranasal dexmedetomidine 2 µg/kg (group D) or oral midazolam 0.2 mg/kg and ketamine 5 mg/kg (group MK). The 21 sessions of fractionated radiotherapy were divided into three subgroups of seven consecutive exposures 1-7, 8-14 and 15-21 for comparison. The primary endpoint was to determine the incidence of successful sedation. The sedation score achieved, time to satisfactory sedation and discharge, rescue ketamine required, and side effects were secondary endpoints. Results: The incidence of successful sedation in the three successive RT subgroups; sessions: 1-7, 8-14 and 15-21, was 82%, 75.6% and 66.7% in group D, as compared to 40%, 24.4% and 13.3% in group MK, respectively. (P < 0.001). A decrease in successful sedation was noted in the successive subgroups. Time to successful sedation and discharge was earlier in group D in comparison to MK (P = 0.000). More patients in group MK required rescue ketamine (P = 000). Conclusion: Intranasal dexmedetomidine produces more satisfactory sedation as compared to oral ketamine with midazolam for fractionated RT.

Near-infrared stimulated hydrogel patch for photothermal therapeutics and thermoresponsive drug delivery.

Nanotechnology driven cancer theranostics hold potential as promising future clinical modalities. Currently, there is a strong emphasis on the development of combinational modalities, especially for cancer treatment. In this study, we present a topical hydrogel patch for nanomaterial-assisted photothermal therapeutics as well as for on-demand drug delivery application. The patch was derived from interpenetrating networks (IPNs) of alginate (Alg) and polyacrylamide (PAAm) in weight ratio 8:1 by free radical polymerization. The patch interiors were composed of hybrid nanostructures derived from gold nanorods (AuNRs) anchored onto polyvinylpyrrolidone (PVP) functionalized graphene oxide (PVP-nGO) to form PVP-nGO@AuNRs hybrids. Field emission scanning electron microscopy (FE-SEM) images revealed the porous nature of the hybrid hydrogel patch with an average pore size of ~28.60 ± 3.10 µm. Besides, functional characteristics of the hybrid patch, such as mechanical strength, viscoelastic and swelling behavior, were investigated. Under near-infrared (NIR) radiation exposure, the hybrid patch exhibited photothermal properties such as surface temperature rise to 75.16 ± 0.32 °C, sufficient to ablate cancer cells thermally. Besides, the heat generated in the hybrid patch could be transmitted to an underlying hydrogel (mimicking skin tissue) when stacked together without much loss. Under cyclic photothermal heating, the patch could retain its photothermal stability for four cycles. Furthermore, the hybrid patch demonstrated NIR stimulated drug release, which was evaluated using methotrexate (MTX, water-insoluble anticancer drug) and rhodamine B (RhB, water-soluble dye). Taken together, this work provides a new dimension towards the development of externally placed hydrogel patches for thermal destruction of localized solid tumors and tunable delivery of chemotherapeutic drugs at the target site.

Antibody-labeled Gold Nanoparticles Based Immunosensor for the Detection of Thyroxine Hormone.

Immunosensors are used to provide simple, quick and effective ways to detect analytes for the diagnosis of a number of diseases. This work reports on a novel optical immunosensor based on thyroxine antibody labeled gold nanoparticles (anti-T4/C-AuNPs) for the sensitive detection of the thyroxine (T4) hormone. T4 hormone is a reliable diagnostic biomarker present in the human blood serum that is necessary for normal neural development and cellular metabolism. The free T4 hormone, a major key player of the total biologically active T4 hormone, in serum regulates the patient's thyroid function. The immunosensor was synthesized by using amine functionalized cysteamine capped gold nanoparticles (C-AuNPs) of size 36 nm approximately. The T4 specific antibody (anti-T4) was covalently attached to C-AuNP by EDC-NHS (1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride and N-hydroxysuccinimide) cross-linking chemistry. This anti-T4/C-AuNP bioconjugate was used for the analysis of the free thyroxine hormone in samples. The proposed method exhibited high performance immunosensors having a linear range of 0.52 to 65.1 pg/mL and the detection limit of 9.11 pg/mL.

Antimicrobial properties of the novel bacterial isolate Paenibacilllus sp. SMB1 from a halo-alkaline lake in India.

Antibiotic-resistance is ever growing burden on our society for the past many years. Many synthetic chemistry approaches and rational drug-design have been unable to pace up and tackle this problem. Natural resources, more specifically, the microbial diversity, on the other hand, make a traditional and still the best platform to search for new chemical scaffolds and compounds. Here, we report the antimicrobial characteristics of novel bacterial isolate from a salt lake in India. We screened the bacterial isolates for their inhibitory activity against indicator bacteria and found that four novel species were able to prevent the growth of test strains studied in vitro. Further, we characterized one novel species (SMB1T = SL4-2) using polyphasic taxonomic approaches and also purified the active ingredient from this bacterium. We successfully characterized the antimicrobial compound using mass spectroscopy and amino acid analysis. We also allocated two novel biosynthetic gene clusters for putative bacteriocins and one novel non-ribosomal peptide gene cluster in its whole genome. We concluded that the strain SMB1T belonged to the genus Paenibacilllus with the pairwise sequence similarity of 98.67% with Paenibacillus tarimensis DSM 19409T and we proposed the name Paenibacillus sambharensis sp. nov. The type strain is SMB1T (=MTCC 12884 = KCTC 33895T).

Pseudomonas koreensis Recovered From Raw Yak Milk Synthesizes a ß-Carboline Derivative With Antimicrobial Properties.

Natural evolution in microbes exposed to antibiotics causes inevitable selection of resistant mutants. This turns out to be a vicious cycle which requires the continuous discovery of new and effective antibiotics. For the last six decades, we have been relying on semisynthetic derivatives of natural products discovered in "Golden Era" from microbes, especially Streptomyces sp. Low success rates of rational drug-design sparked a resurgence in the invention of novel natural products or scaffolds from untapped or uncommon microbial niches. Therefore, in this study, we examined the microbial diversity inhabiting the yak milk for their ability to produce antimicrobial compounds. We prepared the crude fermentation extracts of fifty isolates from yak milk and screened them against indicator strains for the inhibitory activity. Later, with the aid of gel filtration chromatography followed by reversed-phase HPLC, we isolated one antimicrobial compound Y5-P1 from the strain Y5 (Pseudomonas koreensis) which showed bioactivity against Gram-positive and Gram-negative bacteria. The compound was chemically characterized using HRMS, FTIR, and NMR spectroscopy and identified as 1-acetyl-9H-ß-carboline-3-carboxylic acid. It showed minimum inhibitory activity (MIC) in the range of 62.5-250 µg /ml. The cytotoxicity results revealed that IC50 against two mammalian cell lines i.e., HepG2 and HEK293T was 500 and 750 µg/ml, respectively. This is the first report on the production of this derivative of ß-carboline by the microorganism. Also, the study enlightens the importance of microbes residing in uncommon environments or unexplored habitats in the discovery of a diverse array of natural products which could be designed further as drug candidates against highly resistant pathogens.

Salibacterium nitratireducens sp. nov., a haloalkalitolerant bacterium isolated from a water sample from Sambhar salt lake, India.

A strictly aerobic, haloalkali-tolerant, Gram-stain-positive, non-motile, rod-shaped bacterium, designated strain SMB4T, was isolated from a water sample collected from Sambhar salt lake, Rajasthan, India. Growth occurred at 25-50 °C, 4-12 % (w/v) NaCl and pH of 5-9. Strain SMB4T was positive for ß-galactosidase, oxidase, catalase and urease activities. The fatty acids were dominated by branched forms of fatty acids with iso- and anteiso-saturated fatty acids, with a high abundance of anteiso-C15 : 0, anteiso-C17 : 0 and C18 : 0. The cell-wall peptidoglycan of strain SMB4T contained meso-diaminopimelic acid, while the polar lipids included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and three unidentified lipids. The DNA G+C content of strain SMB4T was 49.1 mol%. A blast sequence similarity search based on 16S rRNA gene sequence indicated that Salibacterium halochares, Salibacterium halotolerans and Salibacterium qingdaonense were the nearest phylogenetic neighbours, with a pair-wise sequence similarities of 98.4, 98.2 and 97.0 % respectively. Phylogenetic analysis showed that strain SMB4T was clustered with S. halochares and together clustered with S. halotolerans and S. qingdaonense. DNA-DNA hybridization of strain SMB4T with S. halochares DSM 21373T, S. halotolerans S7T and S. quigdaonense DSM 21621T showed a relatedness values of only 39.8, 26.3 and 42.8 %, respectively. Based on its phenotypic characteristics and on phylogenetic inference, strain SMB4T represents a novel species of the genus Salibacterium, for which the name Salibacterium nitratireducens sp. nov. is proposed. The type strain is SMB4T (=MTCC 12633T=KCTC 33876T=JCM 32187T).

Bacillus alkalilacus sp. nov., isolated from a sediment sample from a lake in India.

An aerobic, endospore-forming, haloalkali-tolerant, Gram-stain-positive, motile, rod-shaped bacterium, designated strain AK73T, was isolated from a sediment sample collected from Sambhar lake, Jaipur, Rajasthan, India. Colonies were circular, 1-2 mm in diameter, glossy, smooth, yellowish and convex with an entire margin after 48 h growth on marine agar at pH 9 and 37 °C. Growth occurred at 15-42 °C, 0-10 % (w/v) NaCl and at a pH range of 7-12. Strain AK73T was positive for catalase and arginine dihydrolase 2 activities, hydrolysis of Tweens 20, 40 and 80, and negative for esculinase, caseinase, gelatinase, ß-galactosidase, lipase (Tween 60) and urease activities. The fatty acids were dominated by branched iso-, anteiso-, saturated fatty acids with a high abundance of iso-C15 : 0, anteiso-C15 : 0, C16 : 0 and anteiso-C17 : 0; MK-7 was the major menaquinone. The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, one unidentified aminophospholipid, four unidentified phospholipids and three unidentified lipids. The DNA G+C content of strain AK73T was 54 mol%. Analysis based on comparative 16S rRNA gene sequence analysis indicated that Bacillus alcalophilus was the nearest phylogenetic neighbour, with a pair-wise sequence similarity of 96.0 %. Phylogenetic analysis showed that strain AK73T formed a separate lineage but was loosely associated with a peripheral cluster of organisms that contained Bacillus gibsonii, Bacillus murimartini and Bacillus plakortidis with similarity values of 93.6, 93.5 and 93.4 %, respectively. Based on its phenotypic characteristics and on phylogenetic inference, strain AK73T represents a novel species of the genus Bacillus, for which the name Bacillus alkalilacus sp. nov. is proposed. The type strain is AK73T (=JCM 32184T=MTCC 12637T=KCTC 33880T).

Sphingobacterium bovisgrunnientis sp. nov., isolated from yak milk.

A novel Gram-negative, rod shaped, non-motile bacterium, designated strain YK2T, was isolated from yak milk from Leh, India. The strain was positive for oxidase- and catalase-activities and negative for starch hydrolysis, nitrate reduction, citrate utilization, urease, lysine decarboxylase and ornithine decarboxylase activities. The predominant fatty acids were iso-C15 : 0, iso-C17 : 0 3-OH, iso-C17 : 1ω9c and C16 : 1ω7c and/or C16 : 1ω6c and/or iso-C15 : 0 2-OH (summed feature 3). The major polar lipids were phosphatidylethanolamine, one unidentified aminophospholipid and six unidentified lipids. The DNA G+C content of the strain was 38.9 mol%. The 16S rRNA gene sequence analysis indicated that strain YK2T was a member of the genus Sphingobacterium and closely related to Sphingobacterium alimentarium and Sphingobacterium composti with pair-wise sequence similarity of 98.3 and 97.9 %, respectively. The sequence similarity to other members of the genus Sphingobacterium was between 92.6 to 96.3 %. Phylogenetic analysis showed that strain YK2T clustered with Sphingobacterium alimentarium and together clustered with Sphingobacterium composti. DNA-DNA hybridization of strain YK2T with Sphingobacterium alimentarium WCC 4521T and Sphingobacterium composti T5-12T showed a relatedness of only 38 and 54 %, respectively. Based on the phenotypic characteristics and on phylogenetic inference, it appears that strain YK2T represents a novel species of the genus Sphingobacterium, for which the name Sphingobacterium bovisgrunnientis sp. nov. is proposed. The type strain of Sphingobacterium bovisgrunnientis sp. nov. is YK2T (=MTCC 12631T=KCTC 52685T=JCM 31951T).

Bacillus lacus sp. nov., isolated from a water sample of a salt lake in India.

A strictly aerobic, alkaliphilic, Gram-stain-positive, motile, rod-shaped bacterium, designated strain AK74T, was isolated from a water sample collected from Sambhar salt lake, Rajasthan, India. Colonies were circular, 1.2 mm in diameter, shiny, smooth, whitish and convex with an entire margin after 48 h growth at 37 °C with pH 9.0. Growth occurred at 25-42 °C, 0-4 % (w/v) NaCl and at a pH of 7-12. Strain AK74T was positive for aesculinase, caseinase, lipase activities and negative for oxidase, catalase, amylase, cellulase, DNase, gelatinase and urease activities. The fatty acids were dominated by branched iso-, anteiso- and saturated fatty acids with a high abundance of iso-C15 : 0, anteiso-C15 : 0, C16 : 0 and C16 : 1 and the cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid. The DNA G+C content of strain AK74T was 51.6 mol%. A blast sequence similarity search based on 16S rRNA gene sequences indicated that Bacillus niabensis, Bacillus idriensisand Bacillus halosaccharovorans were the nearest phylogenetic neighbours, with a pair-wise sequence similarities of 96.6, 96.6 and 96.5%, respectively. Phylogenetic analysis showed that strain AK74T clustered with Bacillus mangrove and together clustered with Bacillus idriensisand Bacillus indicus. Based on its phenotypic characteristics and on phylogenetic inference, strain AK74T represents a novel species of the genus Bacillus, for which the name Bacilluslacus sp. nov. is proposed. The type strain is AK74T (=MTCC 12638T=KCTC 33946T=JCM 32185T).

High-Performance Symmetrical Supercapacitor with a Combination of a ZIF-67/rGO Composite Electrode and a Redox Additive Electrolyte.

The synthesis of a highly porous composite of ZIF-67 and reduced graphene oxide (rGO) using a simple stirring approach is reported. The composite has been investigated as an electrode to be assembled in a supercapacitor. In the presence of an optimized redox additive electrolyte (RAE), that is, 0.2 M K3[Fe(CN)6] in 1 M Na2SO4, the ZIF-67/rGO composite electrode has combined the properties of improved conductivity, high specific surface area, and low resistance. The proposed composite electrode in the three-electrode system shows an ultrahigh specific capacitance of 1453 F g-1 at a current density of 4.5 A g-1 within a potential window of -0.1 to 0.5 V. Further, the ZIF-67/rGO composite electrode was used to fabricate a symmetrical supercapacitor whose operation in the presence of the RAE has delivered high values of specific capacitance (326 F g-1 at a current density of 3 A g-1) and energy density (25.5 W h kg-1 at a power density of 2.7 kW kg-1). The device could retain about 88% of its initial specific capacitance after 1000 repeated charge-discharge cycles. The practical usefulness of the device was also verified by combining two symmetrical supercapacitors in series and then lighting a white light-emitting diode (illumination for 3 min). This study, for the first time, reports the application of a ZIF-based composite (ZIF-67/rGO) in the presence of an RAE to design an efficient supercapacitor electrode. This proposed design is also scalable to a flexible symmetric device delivering high values of specific capacitance and energy density.

Impact of infrared treatment on quality and fungal decontamination of mung bean (Vigna radiata L.) inoculated with Aspergillus spp.

BACKGROUND: Mung bean is a rich source of protein, carbohydrates and fiber content. It also exhibits a high level of antioxidant activity due to the presence of phenolic compounds. Aspergillus flavus and A. niger are the two major fungal strains associated with stored mung bean that lead to post-harvest losses of grains and also cause serious health risks to human beings. Thus there is a need to explore an economical decontamination method that can be used without affecting the biochemical parameters of grains. RESULTS: It was observed that infrared (IR) treatment of mung bean surface up to 70 °C for 5 min at an intensity of 0.299 kW m-2 led to complete visible inhibition of fungal growth. Scanning electron microscopy revealed that surface irregularities and physical disruption of spores coat are the major reasons behind the inactivation of IR-treated fungal spores. It was also reported that IR treatment up to 70 °C for 5 min does not cause any negative impact on the biochemical and physical properties of mung bean. CONCLUSION: From the results of the present study, it was concluded that IR treatment at 70 °C for 5 min using an IR source having an intensity of 0.299 kW m-2 can be successfully used as a method of fungal decontamination. The fungal spore population was reduced (approximately 5.3 log10 CFU g-1 reductions) without significantly altering the biochemical and physical properties of grains. © 2017 Society of Chemical Industry.

Changes in rheological properties of wheat due to storage.

BACKGROUND: The present study aimed to investigate changes in the fundamental rheological properties of dough prepared from wheat grains stored for 6 months at 20 °C, at ambient temperature (temperature varied with time) and at 4 °C. Stress/shear rate ramp, oscillation and creep-recovery tests were performed to assess the changes in rheological properties as a result of storage. RESULTS: Samples were observed to be non-Newtonian; thus, the Bingham model estimated the yield stress, which was maximum for the wheat stored under ambient conditions and minimum for wheat stored at 20 °C. The stress required to break the bonds was maximum for wheat-dough stored under ambient conditions and minimum for wheat stored at 20 °C. Wheat stored at 20 °C also had the highest maximum creep and recovery strain. The viscoelastic properties of the three wheat-dough samples were compared. CONCLUSION: The results obtained in the present study show that the wheat-dough prepared under ambient conditions behaves as a rigid and stiff material. The dough prepared from wheat stored at 20 °C had the maximum elasticity. © 2017 Society of Chemical Industry.

Lactic acid bacteria isolated from yak milk show probiotic potential.

Probiotic industries strive for new, efficient and promising probiotic strains that impart a positive impact on consumer health. Challenges are persisting in isolation, screening, and selection of the new indigenous probiotic strains. In the present research, we explored the probiotic potential of 17 lactic acid bacteria isolated from Yak milk in a series of in vitro tests. We also demonstrated their health benefits, i.e., cholesterol degradation, lactose digestion, antimicrobial activity, antioxidant, and anticancer activities. Principal component analysis revealed that more than 50% of the strains fulfilled the examined criteria, e.g., survival in acidic pH, bile concentrations, and adherent property. Approximately all the strains produced antimicrobial substances against the maximum number of tested strains including clinical strains. Most strains degraded cholesterol in comparison to the reference probiotic strain whereas strain Yc showed 1.5 times higher the degradation efficiency of the control strain. Lan4 strain exhibited remarkable anticancer activity and induced the maximum apoptosis (87%) in the Hela cells and was non-toxic to the non-cancerous HEK293 cells. Around ten strains showed positive lactose digestion. Overall, this can be concluded that selected lactic acid bacteria revealed excellent probiotic properties along with desirable health benefits. These strains need to be further investigated in details for their application in the development of novel probiotic preparations for the improvement of public health.

Detection of jaggery syrup in honey using near-infrared spectroscopy.

In the present study, a near-infrared (NIR) filter-based technique along with chemometrics as an analytical tool was used for determination of adulteration of Indian honey with jaggery. A total of 56 honey samples adulterated with different concentrations of jaggery syrup were analyzed using the NIR transflectance method at different wavelengths for multivariate analysis to develop a calibration model for jaggery adulteration in honey samples. The data were compressed using principal component analysis method and the model was developed using partial least square regression. The adulteration of all of the samples can be predicted with a standard error of calibration of 4.55 and a coefficient of determination (R(2)) of 0.81. The results demonstrate that the NIR technique along with chemometrics can be successfully used to determine jaggery adulteration in honey non-destructively.