Concentration Upto Research Articles

The structural, magnetic and electrical properties of zinc-doped orthorhombic calcium ferrite nanoparticles: Memory device and high-frequency applications

Calcium ferrite nanoparticles (NPs), doped with Zinc in the range of 10–50[Formula: see text]mol%, were synthesized through a solution combustion method using citrus Limon extract as a reducing agent, followed by calcination at 500∘C. The synthesized samples are characterized with different techniques. Bragg reflections confirmed the formation of orthorhombic crystal structure. The shifting of the peak toward higher angle side is observed with increase in the dopant concentration. The surface exhibited irregular shapes and sized NPs with pores and voids in their morphology. The direct energy band gap increases from 2.91 to 2.97[Formula: see text]eV with increase in Zinc concentration. Further, magnetic and dielectric properties were carried out to know their importance in the high-frequency devices. Magnetic parameters, such as saturation magnetization (Ms), remanence (Mr), and coercivity (Hc) values, are discussed. Ms, Mr and Hc increase with increase in dopant concentration upto 30[Formula: see text]mol% and thereafter decreases. The dielectric studies revealed a decreasing dielectric constant from 2.98 to 1.84 as the dopant concentration increased. These findings suggest the potential use of these samples in memory devices and high-frequency applications.

Biodegradation of Bifenthrin using the Bacterium, Pseudomonas stutzeri (MTCC2300)

Introduction: Pyrethroid pesticides are applied in agricultural fields to protect crop protection from pests and their residues, whichcan adversely affect soil and water quality, causing damage to non-target organisms. This research aimed to explore the potential role of the bacterial strain, Pseudomonas stutzeri in breaking down the pesticide, Bifenthrin. Materials and methods: The study focused on evaluating the efficiency of the bacterium, Pseudomonas stutzeri (MTCC2300) in degrading the pyrethroid, Bifenthrin. Various concentrations of Bifenthrin (2500, 5000, 7500, and 10000 ppm) were were subjected to treatment with the bacterial strain in minimal broth for 16 days. Results: When the efficiency of P.stutzeri on the degradation of 2500, 5000, 7500 and 10000 ppm of Bifenthrin was tested for a period of 16 days, decrease in pH, and an increase in CO2, NH3 and biomass were observed. pH was reduced to 7.6 while CO2 increased upto 4 mg/ml, NH3 upto 0.8mM and Biomass upto 0.6 g dry wt./ml. In two way ANOVA, Bifenthrin concentration resulted in a statistically significant variation in parameters like, pH, CO2 and NH3 of the culture mmedium. . Conclusion: P.stutzeri could tolerate Bifenthrin concentration upto 10000 ppm and it can be employed in Bioremediation programmes for cleaning pyrethroid pesticide polluted sites.

EFFECTIVE REMOVAL AND RECOVERY OF LEAD FROM INDUSTRIAL WASTEWATERS USING NATURAL BIOMASS

Rapid industrialization, urbanization and technological advancement in this century have drastically changed the biogeochemical cycles and balance of some of the heavy metals, thereby leading to environmental pollution in alarming proportions. Lead (i.e., Pb2+) is toxic to most organisms for concentrations higher than 0.05 mg/L, moreover, it is carcinogenic to animals. In the present study, batch biosorption of Pb2+ from wastewaters was studied using the nonliving biomass of Aspergillus sp. and Fusarium sp. isolated from soil. The specific metal removal increased with increase in initial lead ion concentration upto 500 mg/L observed with both the biomasses. A complete removal of the metal was observed at an initial metal ion concentration 50 mg/L and at pH 5.0. A maximum removal of 42.5 mg/g with Fusarium sp. and 37.3 mg/g with Aspergillus sp. was observed at pH 5.0 at 500 mg/L initial lead ion concentration. The adsorption equilibrium was obtained within 1h for all the concentration used. The adsorption equilibrium constants were obtained using both Freundlich and Langmuir adsorption isotherms. The desorption studies disclose the effective recovery of lead from the metal concentrated biomass using 0.1N Nitric acid solution within 0.5 h of time period increasing its effectiveness of reuse.

Detection of free and bound formaldehyde concentration in commercially important fishes and their effect on cooking: A preliminary study

The free and bound formaldehyde concentration in six commercially important fishes from five major fish markets of Tamil Nadu, India were analyzed. The highest concentration of free and bound formaldehyde (9.8 and 6.45 mg/kg) was observed in Sphyraena barracuda and the lowest (0.8 and 0.5 mg/kg) concentration was observed in Lethrinus lentjan. Storage of S. barracuda in ice indicated a significant (p0.05) increase in formaldehyde concentration upto 15 days after which there was a significant increase upto 30 days. S. barracuda spiked with various concentration of formaldehyde followed by boiling for 15 min indicated no significant reduction (p>0.05) in formaldehyde concentration. Formaldehyde treated S. barracuda washed after different time intervals indicated that washing reduces upto 41 to 60% of treated formaldehyde.

The Radioluminescence Investigation of Lead Sodium Borate Glass Doped with Eu3+

The effect of Eu3+-doped lead sodium borate glasses in composition of (79-x)B2O3: 20Na2O: xPbO: 1Eu2O3 and x are 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 and 55 mol%) were studied by using the melt-quenching technique. The absorption spectra show a maximum of 5 transition, where the strongest absorption bands were shown at 394 and 2101 nm in visible light and near-infrared region, respectively. The emission spectra of glasses were measured at 394 nm excitation wavelength. The highest peak of emission spectra corresponding due to 5D0 to 7F2 transition centered at 613 nm. The intensity of emission spectra increased with the increasing of PbO concentration upto 5 mol%. The radioluminescence spectrum (RL) has four peaks similar to photoluminescence, While, the transition at 612 nm strong strongest, identified at 0 mol% of PbO. In addition, the calculated integral scintillation efficiency of 5 mol% is 5.37% as compared with BGO crystal. The values of the color chromaticity coordinates were (0.65, 0.35) locating on the orange region of CIE diagram.

Efficiency Evaluation of Anti-corrosion Treatment of Carbon Steel by Extracts of Red Algae Collected from Mediterranean Coast

The paper presents the assessment of inhibition effectiveness of biomolecules extracted from red seaweed against biocorrosion in the petroleum industry. The first objective of this study was to obtain extracts (A, B and C, prepared respectively from red algae species: Corallina ellongata, Gymnogongrus crenulatus and Pterocladia capillacea) by ethanol extraction method. The infrared spectra of the three extracts confirmed the presence of amine derivatives molecules known by their anti-corrosion inhibiting powers. The second objective was based on the identification of physico-chemical characteristics of the extracts and thus revealing their inhibitory and / or bactericidal power in bacterial corrosion of carbon steel in injection water contaminated with sulfato-reducing bacteria. Biological test of all extracts gave a concentration upto 10 germs/mL in contaminated water by sulfato-reducing bacteria during 28 days of incubation at 37�C. Evolution in time of the open-circuit potential showed a longer incubation time for electrolyte with extracts, whereas the stabilization time was shorter. Current corrosion density, polarization resistance, charge transfer resistance and double layer capacity were determined by using linear polarizarion resistance technique and electrochemical impedance spectroscopy. The corrosion protection efficiency of extract obtained from Gymnogongrus crenulatus (extract B) reached a maximum protective capacity of 99.69% at 5 ppm in the injection water.

Development and performance evaluation of the first in-house multiplex rRT-PCR assay in Bangladesh for highly sensitive detection of SARS-CoV-2

BackgroundThe emergence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic is posing a great threat to global health and economy. Due to the lack of broad diagnostic setup, consistent reagent supply lines, and access to laboratory instruments and equipment, it is undoubtedly an enormous burden for developing countries to face the crisis. ObjectivesTo develop a cost-effective, reliable and sensitive multiplex assay for SARS-CoV-2 screening which would expand the testing capacities of a developing and low-income country like Bangladesh. Study designInitially a singleplex and then a multiplex real-time reverse-transcriptase PCR assays were developed targeting 2 nucleocapsid genes of SARS-CoV-2, and the human RNase P gene as an internal control using laboratory-made mastermixes. Three sets of primer- probes were designed for each of the target genes and one set was optimized for the final reaction set-up. Limit of detection, cross-reactivity and reproducibility were checked in order to assess the sensitivity and specificity of the assays, and validation was done using clinical specimens. ResultsClinical evaluation of the new assays using 240 nasopharyngeal swabs showed 100 % sensitivity, specificity, and accuracy in detecting SARS-CoV-2 infection in human. Equal efficiency and concordant results were observed between the singleplex and multiplex approaches. Notably, the kit was able to detect SARS-CoV-2 RNA at very low concentration upto 5 copies/reaction. ConclusionThis is the first locally developed multiplex rRT-PCR kit in Bangladesh providing rapid and low-cost screening of COVID-19 which would be valuable for infection prevention and clinical management in the perspective of Bangladesh.

Multicomponent transport model-based scaling up of long-term adsorptive filtration of MOF incorporated mixed matrix hollow fiber membrane: Treatment of textile effluent

The present work describes the preparation and detailed characterization of porous chromium terephthalate metal–organic framework (MOF) impregnated polyacrylonitrile based hollow fiber membrane. The hollow fibers were characterized by their surface morphology, zeta potential, permeability, average pore diameter, molecular weight cut off (MWCO) and contact angle. Variation of MOF concentration upto 10 wt% resulted in 43% reduction in membrane permeability. The corresponding change in MWCO was from 140 kDa to 70 kDa. The addition of MOF made the membrane more hydrophilic and at 10 wt% MOF, the contact angle was reduced to 52° from 86°. The Fourier Transform Infrared Spectra (FTIR) of mixed matrix membrane (MMM) showed that there existed strong chemical interaction between MOF particles and polymer backbone, precluding the leaching of MOF from the membrane matrix over long term use. The MOF incorporated MMM exhibited tremendous adsorption capacity (197–260 mg/g for 10 wt% MOF doped fiber) towards reactive dyes commonly used in the textile industry. As the dye removal by MMM hollow fiber was based on the adsorption mechanism, the breakthrough behavior of the membrane was important to estimate the membrane life and onset of membrane regeneration. In the present work, a detailed two-dimensional transient transport model was developed for a multi-component real-life textile effluent from the first principles using the equation of continuity, momentum balance, species balance based on convective-diffusive-adsorptive solute transport in the hollow fiber. The model results were validated with the experimental data of a textile effluent having four reactive dyes. The multicomponent model was used for scaling up the actual hollow fiber based filtration system and the performance curve was generated relating the breakthrough volume, number and length of fibers.

Isolation, Screening and Evaluation of Multifunctional Strains of High Efficient Phosphate Solubilizing Microbes from Rhizosphere Soil

Phosphorus is one of the essential macronutrients which supports plant growth and is obtained from the soil. Phosphate solubilizing micro-organisms helps in solubilizing the insoluble form of phosphates into soluble forms. The present study is aimed to isolate phosphate solubilizing microorganisms from rhizosphere of four plants. P-solubilizing organisms were screened using the Pikovskaya's medium with Tricalcium phosphate as the sole source of phosphate. P-solubilization activity was measured in NBRIP medium and two fungal and bacterial strains obtained from the Colocasia esculenta were selected for their maximum solubilization indices. The selected strains were subjected for morphological, biochemical and genotypic identification and the strains were identified to be Pestalotiopsis microspora, Aquabacterium commune, Bacillus spp., and Aspergillus spp. All the identified strains were subjected to screening against various environmental stresses such as salinity, pH and temperatures. The strains were also tested for intrinsic antibiotic resistance. Finally, the strains were tested for the pesticide tolerance activity against 0.25% Cypermethrin. From these tests, it was observed that the strains were tolerant to salt concentration upto 4%, to temperature upto 37ᵒC. and to pH of 7.8. The strains were tested for the indole acetic acid production activity and were found to be positive for the test. The strains were found to resistant against all the antibiotics except Gentamicin and Co-Trimoxazole. It was also found that the strains were tolerant towards the 0.25% Cypermethrin upto 1g/L. The identified strains were further analyzed by the molecular studies and constructed phylogenetic tree analysis.

Fabrication of Co- and Ce-doped ZnO nanoparticles: a structural, morphological and optical properties investigation

We have analysed the effect of co-doping Rare Earth (Ce) and Transition metal (Co) on optical properties in ZnO nanoparticles. We have prepared 1 at %, 2 at % and 3 at % Ce and Co co-doped ZnO nanoparticles annealed at 600 °C, 700 °C, and 800 °C temperatures by simple sol–gel method using ethanol as a solvent. The structural and morphological properties were characterized by XRD (X-ray Diffraction), RAMAN and SEM (Scanning Electron Microscopy), respectively. All the prepared samples were polycrystalline and wurtzite in structure, showing that Ce and Co have been successfully incorporated into the wurtzite crystal structure of ZnO. Particles were uniformly distributed and the calculated average crystallite size was in the range of 50–100 nm. There was no large shift in the XRD spectra. For optical properties PL (Photoluminescence) spectroscopic and UV–Visible spectroscopic techniques were used. We have obtained two sharp peaks in the PL spectra nearly at 510 and 612 nm. 510 nm emission may be due to trap-state, deep-level emission, whereas, 612 nm emission was due to either charge transfer (CT) transition between O−2 and Ce+4 ion. These two emission peaks were stable with respect to doping concentration upto 2%. The results show that this method produce perfectly co-doped ZnO nanoparticles having sharp emission spectra, so that we can use these materials in LEDs and photodetectors.

POTENTIAL USE OF HAZELNUT PROCESSING PLANT WASTES AS A SORBENT FOR THE SIMULTANEOUS REMOVAL OF MULTI-ELEMENTS FROM WATER

In this paper, the effects of pH (1.5-8.0), initial element concentration (0.5 to 20 mg L−1.) and sorbent dosage (1 - 20 g L-1) were investigated on the potential use of hazelnut processing plant wastes, hazelnut shell (SH) and hazelnut skin (SK), for the simultaneous removal of Al, Cr, Cu, Cd, Pb, As and Fe from water. The surface morphology of the sorbents, elemental analysis, FTIR, SEM-EDS and BET analysis were performed and specific surface areas of the sorbents were found as 0.676 m2 g-1 (for SH) and 0.768 m2 g-1 (for SK). The results showed that surfaces of both sorbents are rough, contains pores that allow to entrap heavy metals and functional groups such as carboxylic acid, phenolic compounds, etc. to which the heavy metal ions can attach. While the optimum pH was determined as 5.0 for all elements in both sorbent systems, the percent removal of heavy metal increased with increase in initial heavy metal concentration up to 8 mg L-1 (except cadmium for SH and copper and cadmium for SK). While optimum sorbent dosage was obtained 10 g L-1 for SH sorbent, increase of sorbent amount led to a decrease of the percentage of removal for SK. Adsorption models were used for the mathematical description of adsorption equilibrium and isotherm constants were evaluated at room temperature (22 ± 2 ◦C). The adsorption equilibrium data were fitted well to Langmuir and Langmuir-Freundlich models in most cases and showed favorable adsorption behavior

Role of Vitreous Humor in Estimating Time Since Death

Background: Estimation of time since death is important for the investigation of crime. This study was done on about 200 medico legal autopsies at KIMS Hospital Bangalore. The information regarding time of death was gathered from hospital records. The data was collected and recorded on proforma and subjected to statistical analysis. Results: The ratio of male and female cases was 1.739:1. Around 42% were in the age group of 21-30 years. Majority of cases were from trauma (43%). The overall range of time since death was 0 to 72 hrs. The overall range of vitreous potassium ion concentration was 3.1 to 24 meq/L and maximum number of cases were in range between 6.1 to 12 meq/l (72%) followed by 3.1 to 6 meq/l (25%). Conclusion: In our present study, we have noticed linear rise of vitreous potassium concentration upto 57 hrs and positive correlation between vitreous potassium concentration and post-mortem interval.

Characterization of arsenite-oxidizing bacteria to decipher their role in arsenic bioremediation

High arsenic groundwater contamination causes serious health risks in many developing countries, particularly in India and Bangladesh. The arsenic fluxes in aquifers are primarily controlled by bacterial populations through biogeochemical cycle. In this present study, two gram-positive rod-shaped bacteria were isolated from shallow aquifers of Bhojpur district in Bihar during the early winter season, able to withstand arsenite (As3+) concentration upto 70 mM and 1000 mM of arsenate (As5+) concentration. They showed high resistance to heavy metals up to 30 mM and utilized some complex sugars along with different carbon sources. Growth at wide range of temperature, pH and salinity were observed. Both these isolates showed high efficiency in converting As3+ into less toxic concentrations of As5+ respectively from arsenic enriched culture media. Along with superior arsenic transformation and arsenic resistance abilities, the isolates showed a wide variety of metabolic capacity in terms of utilizing a variety of carbon sources under aerobic conditions, respectively. This study reports the potential As3+-oxidizing bacteria that can play an important role in subsurface arsenic transformation that will aid in designing future bioremediation strategy for the arsenic affected areas.

Impact of Shewanella oneidensis on heavy metals remobilization under reductive conditions in soil of Guilan Province, Iran

Remobilization of heavy metals in contaminated soil due to anaerobic bioreduction by Shewanella oneidensis was studied. Glucose and anthraquinone-2,6-disulphonate (AQDS) were used as an electron donor and an electron shuttle, respectively. The bioreduction caused a gradual increase in dissolved Mn(II) concentration upto 15 days followed by stationary state. The aqueous Fe(II) concentration increased and reached a highest level on the 10th day, followed by a slight decrease before the steady state was reached. The concentration of Cu(II) was at its extreme level on 5th day and then decreased before reaching the steady state. The highest dissolution was observed for Zn(II) on the 10th day followed by a decrease upto 25th day. Enhanced reduction of Fe(III) and mobilization of selected heavy metals were observed in the presence of S. oneidensis and AQDS. The soluble and acid-extractable Fe(II) concentration was higher in the presence of glucose. The remobilization efficiencies of Mn(II), Fe(II), Cu(II), and Zn(II) were 41%, 48%, 53%, and 63%, respectively. After bioreduction, Fe(II)/Cu(II) and Mn(II)/Zn(II) posed moderate and high risks, respectively. The results of this study will be useful to highlight the effects of variable redox conditions on the bioreduction process to determine the bioavailability of heavy metals in soil.

A new inorganic-organic hybrid halide perovskite thin film based ammonia sensor

A new perovskite material based on ethylene-diamine-dichloride and lead iodide as organic and inorganic precursors respectively was synthesized. Thin films of perovskite material were characterized using SEM, UV-Visible spectroscopy, XRD, and FT-IR. Sensing properties of inorganic organic perovskite thin films were studied and it was found to be selective for ammonia detection. Ammonia being one of the most hazardous and volatile chemical becomes necessary to detect. Color change of perovskite film from yellow to orange was observed in the presence of ammonia vapors. Electrical measurements showed decrease in resistance in the presence of ammonia vapors. Low concentration upto 50 ppm can be easily detected in approximately 40 s. The present method for detecting ammonia is unique, simple, selective, low cost and can be easily implemented for the field studies.

Chromatic detection of glucose using polymerization of diacetylene vesicle

ABSTRACTA polydiacetylene vesicle was used to fabricate glucose sensor, allowing feasible colorimetric detection. The vesicle was formed by sonication of 10,12‐pentacosadiynoic acid (PCDA). H2O2 formed by the reaction between glucose and glucose oxidase functioned as the initiator for the polymerization of PCDA in the presence of horseradish peroxidase. The solution turned blue after the polymerization of PCDA vesicle. Thus, the glucose concentration could be detected to the concentration level that turns the solution to blue. The ultraviolet absorbance of glucose solution was proportional to glucose concentration. The results of this study indicate that glucose concentration upto 1 mM can be detected by change in blue color by eyes. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46394.

Role of europium on WO3 performance under visible-light for photocatalytic activity

Photocatalytic degradation of organic dyes in wastewater using visible light illumination is a green technology which requires efficient visible-light driven active catalytic material. For this, we have reported a novel visible light active Eu/WO3system with variation in europium contents (0, 2%, 4% and 6% Eu), which demonstrated enhanced photocatalytic activity for the degradation of various organic dyes including methylene blue (MB), methyl orange ((MO) and rhodamine B (RhB). Scanning electron microscopy (SEM), X-ray diffractometer (XRD), energy dispersive X-ray (EDX), UV–visible spectroscopy and photoluminescence (PL) spectroscopy were used for the characterization of nanostructures. The results showed that Eu has effective role in modifying the structural, morphological and optical properties of WO3 photocatalyst. Moreover, the photocatalytic performance of WO3 was improved due to incorporation of Eu. From results, it was seen that photocatalytic activity increases with increasing Eu concentration upto 4%, however, further increase in Eu concentration (6%) has decreased the performance under these condition for all dyes. The enhanced photocatalytic efficiency could be attributed to suppressed recombination of charge carriers and enhanced visible light absorption and increased BET surface area due to Eu doping into WO3 photocatalyst. The as-synthesized nanostructures will be considered as a promising photocatalytic materials for the future research in this field.

Preparation of NGF encapsulated chitosan nanoparticles and its evaluation on neuronal differentiation potentiality of canine mesenchymal stem cells.

Sustained and controlled release of neurotrophic factors in target tissue through nanomaterial based delivery system could be a better strategy for nerve tissue regeneration. The present study aims to prepare the nerve growth factor (NGF) encapsulated chitosan nanoparticles (NGF-CNPs) and its evaluation on neuronal differentiation potentiality of canine bone marrow derived mesenchymal stem cells (cBM-MSCs). The NGF-CNPs were prepared by ionotropic gelation method with tripolyphosphate (TPP) as an ionic cross-linking agent. Observations on physiochemical properties displayed the size of nanoparticles as 80-90 nm with positive zeta potential as well as an ionic interaction between NGF and nanoparticle. NGF loading efficiency was found to be 61% while its sustained release was observed by an in vitro release kinetics study. These nanoparticles were found to be cytocompatible to cBM-MSCs when supplemented at a concentration upto 4 mg/ml in culture media. The NGF-CNP supplemented culture media was able to transdifferentiate the preinduced cBM-MSCs into neurons in a better way than unbound NGF supplementation. Further, it was also noticed that NGF-CNPs were able to transdifferentiate cBM-MSCs without any chemical based preinduction. In conclusion, our findings propose that NGF-CNPs are capable of releasing bioactive NGF with the ability to transdifferentiate mesenchymal stem cells into neurons, suggesting its potential future application in nerve tissue regeneration.

Sunlight-assisted photocatalytic degradation of textile effluent and Rhodamine B by using iodine doped TiO2 nanoparticles

Abstract Iodine-doped TiO2 nanoparticles (I@TiO2 NPs), in different mol percentage (mol%) of iodine with anatase phase only, have been prepared by using simple sol-gel method. Samples were characterized by various physico-chemical techniques. Physico-chemical characterization revealed that crystallite size, surface hydroxylation, and tuning of optical band gap towards visible region of composites increases with increase in dopant concentration upto 7.0 mol% in TiO2 host lattice. Thereafter, the samples were used to photocatalytic degradation of textile effluent (TE) as well as Rhodamine B (RhB) under sunlight irradiation directly. The progress of photodegradation reaction was monitored by UV–visible spectroscopy. The chemical oxygen demand (COD) of TE samples was evaluated before and after photocatalytic studies. During photocatalytic reaction, the effect of pH and amount of catalyst on the rate of degradation reaction was also studied. It is clearly shown that I@TiO2 particles result in the enhancement of the degradation ability of RhB as well as TE in sunlight.

Experimental investigations on nucleate boiling heat transfer of aqua based reduced graphene oxide nanofluids

In this work, reduced graphene oxide (rGO) is synthesized from graphite powder and various characterization techniques have been used to study the in-plane crystallite size, number of layers, presence of functional groups and surface morphology. The rGO flakes are dispersed in Millipore water to obtain 0.0005, 0.001, and 0.002 wt.% of rGO-water nanofluids. It is then used in the experimental facility to study the nucleate boiling heat transfer with different heating surfaces viz. smooth and sandblasted surface (SBS). Results of this study indicate (i) an enhancement in heat transfer coefficient (HTC) for concentration upto 0.001 wt.% and deterioration beyond this in the case of smooth surface, and (ii) an increase in HTC with concentrations is observed for SBS and shows a maximum enhancement of about 60% in comparison with smooth surface at 0.002 wt.%. It is found that the presence of secondary cavities (acts as nucleation sites) formed by the rGO flakes during boiling is responsible for the observed phenomena in addition to the possible effect of rGO in the fluid flow.