Photoluminescence Quenching Based Visual and Spectroscopic Method for Mercury Sensing by Surface-Modified Cadmium Sulphide Quantum Dots.

Here we present a simple yet efficient analytical method for sensing ultratrace levels of Hg2+ ions by highly water soluble CdS quantum dots functionalized with thiourea as a probe. The bluish photoluminescence emission of the probe responded to a systematic linear photoluminescence quenching in the presence of increasing concentration of Hg2+ ions. The photoluminescence quenching by Hg2+ ions was attributed to agglomeration of the quantum dots, which has been confirmed by zeta potential measurements. The sensitivity (31.38 L/mg) and LoD (0.11 µg/L) of Hg2+ ion detection by our method are two folds improved with respect to the existing data of CdS as sensor. The improved detection is attributable to synthesis of less than 3 nm diameter CdS quantum dots which rendered very high water solubility and hence facilitated better interaction with Hg2+ ions. The detection of Hg2+ ion was free from most interfering cations and anions, except for minor interference from Cu2+ and Pb2+ corresponding their concentrations expected in ground water. Further, the scope for visual detection of Hg2+ was explored, which revealed naked eye recognizable photoluminescence quenching of the probe treated 0.3 mg/L of Hg2+ ion when excited by a light source of 365 nm. The suitability of our probe to analyze Hg2+ in real samples has been demonstrated by Hg2+ spike analysis in groundwater and river water samples.

Highly Sensitive and Selective Method for Detecting Ultratrace Levels of Aqueous Uranyl Ions by Strongly Photoluminescent-Responsive Amine-Modified Cadmium Sulfide Quantum Dots.

Detection of ultratrace levels of aqueous uranyl ions without using sophisticated analytical instrumentation and a tedious sample preparation method is a challenge for environmental monitoring and mitigation. Here we present a novel yet simple analytical method for highly sensitive and specific detection of uranyl ions via photoluminescence quenching of CdS quantum dots. We have demonstrated a new approach for synthesizing highly water-soluble and strong photoluminescence-emitting CdS quantum dots (i.e., CdS-MAA and CdS-MAA-TU) of sizes less than 3 nm. The structural, morphological, and optical properties of both the batches of CdS quantum dots were thoroughly characterized by XRD, high-resolution transmission electron microscopy (HRTEM), zeta potential, UV-visible absorption, and photoluminescence spectroscopy. Compared to the batch of CdS quantum dots prepared by capping with only mercaptoacetic acid (CdS-MAA), the batch prepared by capping with mercaptoacetic acid and thiourea in tandem (CdS-MAA-TU) exhibited higher quantum yield= 16.64 ± 1.02%, and more importantly, CdS-MAA-TU exhibited significantly a higher order of photoluminescence quenching responses when treated with ultratrace concentrations of uranyl ions. Under the optimized conditions, the sensitivity of detecting uranyl ion by CdS-MAA-TU was several folds better (0.316 L/ µg) than that of CdS-MAA (0.0053 (L/µg/), as determined from their respective Stern-Volmer plots. Qualitatively, CdS-MAA-TU probe can be used for visual detection of uranyl ions of concentration greater than 5 µg/L. However, the instrumental method of analysis based on photoluminescence spectroscopy confirmed the feasibility for quantitative analysis of ultratrace concentrations of uranyl ions as implied from a very low limit of detection (LoD = 0.07 µg/L) and limit of quantification (LoQ = and 0.231 µg/L). Systematic studies revealed very high selectivity for uranyl ion detection, though minor interference from Cu(2+), Pb(2+), Hg(2+), CO3(2-), and SO4(2-) was found. The recovery analysis performed by spiking uranyl ions (0.5 µg/L to 10.0 µg/L) in groundwater and river water samples, confirmed the robustness of the as-developed CdS-MAA-TU QDs for detecting ultratrace levels of uranyl ions in real water sample matrix. The very simple and effective strategy reported here should facilitate developing reliable sensors for detecting uranyl ion contamination in drinking water.

Antibacterial effect of chronic exposure of low concentration ZnO nanoparticles on E. coli.

The toxicity effect due to chronic exposure of ZnO nanoparticles (NPs) was systematically studied by repeatedly treating different lower concentrations of ZnO nanoparticles with culture media of E. coli strain. The chronic exposure of ZnO NPs of concentrations below minimum inhibitory concentration (MIC) exhibited higher toxicity than the single exposure of higher concentrations. Most striking result was 57% inhibition of growth corresponding to chronic exposure of 0.06 mg/mL of ZnO NPs which was two folds more than that exhibited by single exposure of 0.30 mg/mL ZnO NPs. The toxicity of ZnO NPs in E. coli was studied in the light of formation of reactive oxygen species (ROS), measured as malondialdehyde (MDA) equivalent by thiobarbituric acid-ROS (TBARS) assay, and effect of Zn dissolution from ZnO NPs. Higher inhibition of growth for the chronic exposure batches were correlated with higher ROS generation, which subsequently contributed to cause membrane lipid peroxidation, confirmed from observation of cell wall deformation by scanning electron microscopy study and energy dispersive X-ray analysis showed adherence of ZnO NPs on cell wall. The possibility of membrane lipid peroxidation was addressed by revealing in vitro oxidation of oleic acid, which is a monounsaturated fatty acid. Further in this study we have shown that the dissolution of ZnO NPs at pH 7.4 was not significant to cause Zn-induced toxicity.

Chemical analysis of low carbon content coals and their applications as dye adsorbent.

Coal is primarily a fuel material but lately it has been utilized as an adsorbent for removing toxic metal ions. However, its usage for removing organic pollutants is not well studied. We report here a systematic study on the use of coal samples of varying carbon contents as adsorbents for removing Basic Blue 41 as a model cationic dye. The coal samples were collected from coal mines and were thoroughly characterized. The concentrations of carbon, hydrogen, oxygen, nitrogen and sulphur contents were measured by CHNS analyzer. The concentrations of aluminum, silicon, sulphur, titanium and iron were determined by EDXRF, which corresponded to silicon dioxide (quartz) and aluminium silicate (kaolinite) as the major mineral inclusions, corroborated by XRD results and micrographs showing elemental maps determined from SEM-EDAX. The coal samples with low carbon content revealed higher adsorption capacity (qe âˆ¼ 8.0-9.3 mg/g) of Basic Blue dye at optimized adsorbent dose (2 mg/mL), pH 9 and contact time (120 min). The adsorption kinetic studies satisfied pseudo second order model and the intra-particle diffusion of the dye was evident. The dye adsorption followed Langmuir adsorption isotherm, and the qmax values ranged between 17 and 30 mg/g for low carbon content coal. The FT-IR, Brunauer-Emmett-Teller (BET) surface area and zeta potential results of the coal samples could explain the adsorption phenomenon of cationic dye. The kinetic and thermodynamic studies revealed that the adsorption of Basic Blue 41 dye was based on chemisorptions mechanism.

Gene-specific MicroRNA antagonism protects against HIV Tat and TGF-ß-mediated suppression of CFTR mRNA and function.

BACKGROUND: MicroRNAs play an important role in health and disease. TGF-ß signaling, upregulated by HIV Tat, and in chronic airway diseases and smokers upregulates miR-145-5p to suppress cystic fibrosis transmembrane conductance regulator (CFTR). CFTR suppression in chronic airway diseases like Cystic Fibrosis, COPD and smokers has been associated with suppressed MCC and recurrent lung infections and inflammation. This can explain the emergence of recurrent lung infections and inflammation in people living with HIV. METHODS: Tat-induced aberrant microRNAome was identified by miRNA expression analysis. microRNA mimics and antagomirs were used to validate the identified miRNAs involved in Tat mediated CFTR mRNA suppression. CRISPR-based editing of the miRNA target sites in CFTR 3'UTR was used to determine rescue of CFTR mRNA and function in airway epithelial cell lines and in primary human bronchial epithelial cells exposed to TGF-ß and Tat. FINDINGS: HIV Tat upregulates miR-145-5p and miR-509-3p. The two miRNAs demonstrate co-operative effects in suppressing CFTR. CRISPR-based editing of the miRNA target site preserves CFTR mRNA and function in airway epithelial cells INTERPRETATION: Given the important roles of TGF-ß signaling and the multitude of genes regulated by miRNAs, we demonstrate that CRISPR-based gene-specific microRNA antagonism approach can preserve CFTR mRNA and function in the context of HIV Tat and TGF-ß signaling without suppressing expression of other genes regulated by miR-145-5p.

Heavy metal bioaccumulation in selected medicinal plants collected from Khetri copper mines and comparison with those collected from fertile soil in Haridwar, India.

Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6-76.5 mg kg(-1)) than those from Haridwar samples (7.40-15.3 mg kg(-1)), which is correlated with very high copper levels (763 mg kg(-1)) in Khetri soil. Among various heavy metals, Cr (2.60-5.92 mg kg(-1)), Cd (1.47-2.97 mg kg(-1)) and Pb (3.97-6.63 mg kg(-1)) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4-69.3 mg kg(-1)), Fe (192-601 mg kg(-1)), Zn (24.9-49.9 mg kg(-1)) and Se (0.13-0.91 mg kg(-1)) and potentially toxic metals like Ni (3.09-9.01 mg kg(-1)) and As (0.41-2.09 mg kg(-1)) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.

Novel Approaches of CRISPR-Cas Technology in Airway Diseases.

Clustered regularly interspaced palindromic repeats (CRISPR) technique plays a vital role in preclinical modelling of many respiratory diseases. Diseases such as chronic obstructive pulmonary disease (COPD), asthma, acute tracheal bronchitis, pneumonia, tuberculosis, lung cancer, and influenza infection continue to significantly impact human health. CRISPR associated (Cas) proteins, isolated from the immune system of prokaryotes, are one component of a very useful technique to manipulate gene sequences or editing and gene expression with significant implications for respiratory research in the field of molecular biology. CRISPR technology is a promising tool that is easily adaptable for specific editing of DNA sequences of interest with a goal towards modifying or eliminating gene function. Among its many potential applications, CRISPR can be applied to correcting genetic defects as well as for therapeutic approaches for treatment. This review elucidates recent advances in CRISPR-Cas technology in airway diseases.

TGF-ß1 increases viral burden and promotes HIV-1 latency in primary differentiated human bronchial epithelial cells.

Combination antiretroviral therapy (cART) has increased the life expectancy of HIV patients. However, the incidence of non-AIDS associated lung comorbidities, such as COPD and asthma, and that of opportunistic lung infections have become more common among this population. HIV proteins secreted by the anatomical HIV reservoirs can have both autocrine and paracrine effects contributing to the HIV-associated comorbidities. HIV has been recovered from cell-free bronchoalveolar lavage fluid, alveolar macrophages, and intrapulmonary lymphocytes. We have recently shown that ex-vivo cultured primary bronchial epithelial cells and the bronchial brushings from human subjects express canonical HIV receptors CD4, CCR5 and CXCR4 and can be infected with HIV. Together these studies suggest that the lung tissue can serve as an important reservoir for HIV. In this report, we show that TGF-ß1 promotes HIV latency by upregulating a transcriptional repressor BLIMP-1. Furthermore, we identify miR-9-5p as an important intermediate in TGF-ß-mediated BLIMP-1 upregulation and consequent HIV latency. The transcriptionally suppressed HIV can be reactivated by common latency reactivating agents. Together our data suggest that in patients with chronic airway diseases, TGF-ß can elevate the HIV viral reservoir load that could further exacerbate the HIV associated lung comorbidities.

Removal of iron from groundwater by ash: a systematic study of a traditional method.

A traditional method for removal of iron from ground water by using ash has been systematically investigated. Ashes from five different sources, viz., banana rind, banana pseudostem, banana leaf, rice husk and bamboo has been studied. The principle applied is enhanced precipitation of iron at high pH caused by ash. The study included laboratory analysis of some relevant chemical parameters of the ashes and the efficiency of the ashes in removing iron from prefabricated water with respect to quantity of ash and corresponding increase in pH of water. The ash of banana pseudostem has been found to be most suitable for removal of iron. A low-cost and easily made iron removal system for household use has been designed and tested in the laboratory. The ash of banana pseudostem has been found to remove iron to below 0.3ppm without increasing the pH above the acceptable limit. The optimum values of the different parameters for removal of iron are 200-300mgl(-1) ash, 1.0lh(-1) flow rate and 1h of contact time with ash for groundwater having [Fe] of about 2.20ppm. The amount of ash can be increased for groundwater having higher [Fe] and can be decreased gradually during continuous use of the system. Acceptability of the method has been examined based on chemical analysis of the treated water. Increase in the essential minerals such as Ca, K has been observed in the water after treatment. The designed iron removing system is expected to be suitable for household use.

Rapid Photoluminescence Quenching Based Detection of Cu2+ in Aqueous Medium by CdS Quantum Dots Surface Passivated by Thiourea.

Presented here is a simple yet rapid and efficient analytical method for visual as well as spectroscopic method for sensing of trace concentrations of Cu2+ ions in aqueous medium by systematic photoluminescence quenching of a highly water soluble probe made of CdS quantum dots surface modified by thiourea. The salient features of this work describe rapid detection (2 min equilibration time) of Cu2+ ions at wider linear concentration range (0.025 - 10 mg/L) corresponding to a sensitivity of 2.81(mg/L)-1 and limit of quantification of 47.3 µg/L, respectively, suitable for Cu2+ sensing in drinking water and ground water. Further, the detection of Cu2+ ion was free from most interfering cations and anions, except for minor interference from Cr3+, Hg2+ and Pb2+. The robustness of our probe for Cu2+ sensing is demonstrated from efficient Cu2+ spike recovery analysis in groundwater and river water samples.

A novel approach for reducing toxic emissions during high temperature processing of electronic waste.

A novel approach is presented to capture some of the potentially toxic elements (PTEs), other particulates and emissions during the heat treatment of e-waste using alumina adsorbents. Waste PCBs from mobile phones were mechanically crushed to sizes less than 1mm; their thermal degradation was investigated using thermo-gravimetric analysis. Observed weight loss was attributed to the degradation of polymers and the vaporization of organic constituents and volatile metals. The sample assembly containing PCB powder and adsorbent was heat treated at 600°C for times ranging between 10 and 30min with air, nitrogen and argon as carrier gases. Weight gains up to ∼17% were recorded in the adsorbent thereby indicating the capture of significant amounts of particulates. The highest level of adsorption was observed in N2 atmosphere for small particle sizes of alumina. SEM/EDS results on the adsorbent indicated the presence of Cu, Pb, Si, Mg and C. These studies were supplemented with ICP-OES analysis to determine the extent of various species captured as a function of operating parameters. This innovative, low-cost approach has the potential for utilization in the informal sector and/or developing countries, and could play a significant role in reducing toxic emissions from e-waste processing towards environmentally safe limits.

Rapid chelometric determination of lead in lubricating oils via mercaptoacetate extraction.

A rapid complexometric method for the estimation of lead in lubricating oil has been developed. The lead naphthenate present in the oil is extracted with a mixture of dilute thioglycollic acid and nitric acid. The aqueous extract containing lead mercaptoacetate is titrated with EDTA at pH 5 with Xylenol Orange as indicator. The lead content can be determined within 15-20 min.

Spectrophotometric determination of niobium and its application to niobium-stabilized stainless steel.

A spectrophotometric method is described for the determination of niobium by means of its reaction with tannin and thioglycollic acid. The yellow-orange colour developed with the reagent mixture at pH 4 is measured at 410-420 nm and obeys Beer's law between 0.5 and 10 ppm niobium. The method is suitable for the determination of niobium in niobium-stabilized stainless steel and other types of steels containing niobium, but a prior separation of niobium is necessary. Titanium interferes even in traces.

Complexometric determination of magnesium in nodular cast iron and alloyed cast iron roll samples.

A complexometric method for the determination of magnesium in nodular cast iron, alloyed cast iron and roll samples has been developed. The bulk of the iron is removed by ether extraction and the phosphate as zirconium phosphate. The other elements are removed by extraction with dithiocarbamate into chloroform. Magnesium is then titrated with EDTA at pH 10, with Eriochrome Black T as indicator. Calcium interferes, but is very rarely present in such cast iron samples.

Silver-reductor method for determination of iron in iron ores and iron-ore sinters.

A new technique for the quick dissolution of iron ore, magnetite and sinter products has been developed. The sample is dissolved with thioglycollic acid and hydrochloric acid, the excess of thioglycollic acid is oxidized, and the iron is reduced in the silver reductor.

Spectrophotometric determination of vanadium and its application to gas-turbine fuel-oils.

A very sensitive spectrophotometric method for the determination of vanadium in furnace oils is described. The intense indigo-blue colour developed by the reaction of vanadium with tannin and thioglycollic acid is measured at a wavelength of 600 nm at pH 4 and obeys Beer's law between 0.5 and 5 ppm vanadium. The method is applicable to gas-turbine fuel-oil and special navy fuel-oils. The common mineral constituents usually present in such oils do not interfere.

Audiovestibular involvement in leprosy.

100 leprosy patients were studied for audiovestibular involvement. Conductive hearing loss was detected in 6 cases of BT leprosy, all of them having coincidental chronic middle ear infection. Sensori-neural hearing loss was detected in 10 cases, of which 6 had LL, 2 BT and 2 pure neuritic type of disease respectively. All the cases of lepromatous leprosy having sensorineural hearing loss had evidence of ENL reaction. Vestibular involvement was not detected in any of the cases. Evaluation of audiovestibular function was also carried out in 50 fresh cases of leprosy and after 3 months, 6 months and 1 year of multidrug therapy to ascertain any ototoxic side effects of antileprosy drugs. No audiovestibular dysfunction was detected in these patients at any time during follow-up.

Quantification of thermal sensory loss in follow up of progress in leprosy.

Thermal sensory perception quantitatively was studied in follow up of 10 lesions (4 TT, 3 BT and 1 Indeterminate case) of cases put on poly therapy as per WHO regime, for 6 months. Significant thermal sensory improvements was noticed in 4 lesions after 4 months of therapy. Within 2 months of therapy, 3 cases showed improved perception of heat sensation but 1 showed deterioration. Recovery of sensations did not correspond to other clinical parameters of improvement in all the cases. The utility of quantitative evaluation of thermal sensory perception in follow up of leprosy cases is discussed.

Inoculation leprosy developing after tattooing--a case report.

A case of Inoculation Leprosy following tattooing in a soldier is being reported. Escape of infection in one tattoo and occurrence of disease in another when tattooing was done simultaneously, is of interest. Possible mechanism for such occurrence is discussed.

Leprosy with pellagroid features (a case report).

A case of leprosy with pellagroid features is presented. Diagnosis of leprosy was confirmed by bacteriological and histopathological examination. A therapeutic trial with nicotinic acid did not result in any improvement. Occurrence of scaling in leprosy is discussed.