Atomic Absorption Spectroscopy Analysis Research Articles

Nutrient Effect on the Taste of Mineral Waters: Evidence from Europe.

In this study, 15 selected bottled mineral waters from chosen European countries were tested for their mineral nutrient contents. In particular, six important nutrients (Ca2+, Mg2+, Na+, K+, , Cl−) were measured using atomic absorption spectroscopy. The content of mineral nutrients in all sampled mineral waters were compared to their expected content based on the label. Consequently, their taste was evaluated by 60 trained panelists who participated in the sensory analysis. The results from both the atomic absorption spectroscopy and sensory analysis were analyzed using the regression framework. On the basis of the results from the regression analysis, we determined to what extent the individual mineral nutrients determined the taste of the mineral water. According to the regression results, four out of six analyzed nutrients had a measurable impact on taste. These findings can help producers to provide ideal, health-improving nutrients for mineral water buyers.

Arsenic efflux in Enterobacter cloacae RSN3 isolated from arsenic-rich soil.

In the present study, bacterial isolates were screened for arsenic resistance efficiency. Environmental isolates were isolated from arsenic-rich soil samples (i.e., from Rajnandgaon district of Chhattisgarh state, India). Amplification and sequencing of 16S rRNA gene revealed that the isolates were of Bacillus firmus RSN1, Brevibacterium senegalense RSN2, Enterobacter cloacae RSN3, Stenotrophomonas pavanii RSN6, Achromobacter mucicolens RSN7, and Ochrobactrum intermedium RSN10. Arsenite efflux gene (arsB) was successfully amplified in E. cloacae RSN3. Atomic absorption spectroscopy (AAS) analysis showed an absorption of 32.22% arsenic by the RSN3 strain. Furthermore, results of scanning electron microscopy (SEM) for morphological variations revealed an initial increase in the cell size at 1 mM sodium arsenate; however, it was decreased at 10 mM concentration in comparison to control. This change of the cell size in different metal concentrations was due to the uptake and expulsion of the metal from the cell, which also confirmed the arsenite efflux system.

Impact of Bulk ZnO, ZnO Nanoparticles and Dissolved Zn on Early Growth Stages of Barley-A Pot Experiment.

Zinc is among the most in-demand metals in the world which also means that a considerable amount of this element is released to the environment each year as a result of human activities. A pot experiment was conducted to study the impact of low- and high-dose zinc amendments on plant growth and biomass yield, with Calcic Chernozem as a growing medium and barley (Hordeum vulgare L.) as a model plant. The distribution of zinc in various plant parts was also investigated. Zn (II) was added in powder as bulk ZnO and in solution as ZnO nanoparticles and ZnSO4 in two dosages (3 and 30 mmol kg−1 soil) prior to planting. The plants were harvested after 10 days of growth. The three sets of data were taken under identical experimental conditions. The application of zinc in aqueous solution and in particulate form (having particle sizes in the range of <100 nm to >500 nm) at concentration of 3 and 30 mmol Zn kg−1 to the soil resulted in decreased growth (root length, shoot length) and biomass yield; the only exception was the addition of 30 mmol Zn kg−1 in the form of bulk ZnO, which had a positive effect on the root growth. The dry weight reduction (sprout biomass) was lowest in plants grown in soil treated with dissolved zinc. There were no statistically significant changes in the content of chlorophyll a, chlorophyll b, and total chlorophyll, although flame atomic absorption spectrometry (FAAS) analysis indicated that plants bioaccumulated the zinc applied. This implies that the transport of zinc into the above-ground plant parts is controlled by the presence of effective mechanical and physiological barriers in roots. Crop performance under zinc stress in relation to biomass production and the growth of roots and shoots is also partly a reflection of the effects of soil properties. Our findings emphasize the importance of considering plant-soil interactions in research of potential toxicity and bioavailability of zinc in the environment.

Cadmium Tolerance in Alfalfa is Related to the Up-regulation of Iron and Sulfur Transporter Genes along with Phytochelatin Accumulation

Cadmium (Cd) toxicity is a serious limitation for agricultural production. In this study, we explored tolerance mechanism associated with Cd toxicity tolerance in alfalfa plants. We used three distinct alfalfa cultivars M. sativa cv. Vernal, M. sativa cv. Zhung Mu, and M. sativa cv. Xing Jiang Daye in this study. Cd showed declined chlorophyll score in Xing Jiang Daye compared with Zhung Mu and Vernal. No significant change observed among the cultivars for root and shoot length. Atomic absorption spectroscopy analysis demonstrated a significant accumulation of Cd, Fe, S and PC in distinct alfalfa cultivars. However, Zhung Mu and Xing Jiang Daye declined Cd accumulation in root, where Fe, S and PC incremented only in Zhung Mu. It suggests that excess Cd in Zhung Mu possibly inhibited in root by the increased accumulation of Fe, S and PC. This was further confirmed by the response of Fe (MsIRT1) and S transporters (MsSULTR1;2 and MsSULTR1;3), and MsPCS1 genes associated with Fe, S and PC availability and translocation in roots and shoots. It suggests that specially the transcript signal inducing the responses to adjust Cd especially in Zhung Mu. This finding provides the essential background for further molecular breeding program for forage crops.

Amplified Activity of Artesunate Mediated by Iron Oxide Nanoparticles Loaded on a Graphene Oxide Carrier for Cancer Therapeutics.

Development of drugs to tackle the ever-increasing cases of cancer and many other diseases including any pandemic is itself challenging. Repurposing existing drugs is an upcoming drug development strategy established for the reuse of existing licensed drugs to ensure accessible, sustainable, and affordable care against cancer. Herein, we presented a nanochemotherapeutic approach based on PEGylated graphene oxide (GO-PEG) loaded with superparamagnetic iron oxide nanoparticles (NPs) and a sustainable natural origin drug, artesunate (ART) to kill cancerous cells. GO-PEG provided a larger surface area to load the dual cargo, iron oxide NPs (∼40%) and ART (∼13%), at a high loading efficiency and simultaneously affected nanotization and crystallinity of the iron oxide NPs. The morphology and internalization of NPs were determined qualitatively and quantitatively by atomic force microscopy (AFM)-Raman imaging and atomic absorption spectroscopy (AAS) analysis, respectively. Furthermore, the loading and unloading of iron reserves were characterized by high-resolution transmission electron microscopy (TEM) images. The loaded iron oxide NPs underwent a pH-triggered release of iron ions, which is higher in acidic pH than in neutral pH. A ∼sevenfold reduction in the IC50 value of ART upon treatment with the designed nanoconjugate is observed. ART is repositioned as a therapeutic drug against cancer cells, and its efficacy is amplified by the Fenton reaction due to iron oxide NPs, as confirmed by a high oxidative stress generated within the cells. The current work suggests that ART and iron oxide NPs loaded on GO-PEG, a biocompatible carrier, are a promising drug-nanoparticle conjugate for cancer treatment.

Integrated Membrane-Electrocoagulation System for Removal of Celestine Blue Dyes in Wastewater.

The textile industry provides for the needs of people especially in apparel and household items. The industry also discharges dye-containing wastewater that is typically challenging to treat. Despite the application of the biological and chemical treatments for the treatment of textile wastewater, these methods have their own drawbacks such as non-environment friendly, high cost and energy intensive. This research investigates the efficiency of the celestine blue dye removal from simulated textile wastewater by electrocoagulation (EC) method using iron (Fe) electrodes through an electrolytic cell, integrated with nylon 6,6 nanofiber (NF) membrane filtration for the separation of the flocculants from aqueous water. Based on the results, the integrated system achieves a high dye removal efficiency of 79.4%, by using 1000 ppm of sodium chloride as the electrolyte and 2 V of voltage at a constant pH of 7 and 10 ppm celestine blue dye solution, compared to the standalone EC method in which only 43.2% removal was achieved. Atomic absorption spectroscopy analysis was used to identify the traces of iron in the residual EC solution confirming the absence of iron. The EC-integrated membrane system thus shows superior performance compared to the conventional method whereby an additional 10–30% of dye was removed at 1 V and 2 V using similar energy consumptions.

Sensitive and robust colorimetric assay for the detection of Hg2+ at nanomolar level from real samples by TMPM functionalized Ag-Fe NCs and it's photocatalytic and antimicrobial activities

In this study, a selective and sensitive colorimetric probe for the detection of mercury at nanomolar level was reported and the effective detection by the probe was performed with environmental samples. The colorimetric sensing platform was prepared based on Ag-Fe bimetallic- 3-(Trimethoxysilyl) propyl methacrylate framework. The UV–vis spectroscopy, X-Ray diffraction, high resolution transmission electron microscope, energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analyzer, zeta sizer and particle size analyzer were used for the characterization of Ag-Fe nanocomposite. The detection of mercury by Ag-Fe-glycine nanoconjugate was indicated by the colour change from yellowish brown to colourless. The environmental sample was collected from Noyyal river and the estimated amount by the probe was almost similar to the result of atomic absorption spectroscopy analysis. The detailed study on the effect of pH, temperature and saline concentration on the detection was performed. In addition, metal interference study was performed to understand the influence of other metal ions on detection and quantification of Hg2+ by Ag-Fe-glycine nanoconjugate and the study reveals the practical application of the prepared probe. The limit of detection of Hg2+ by Ag-Fe nanocomposite was determined to be 1.8 nM. The prepared probe is found to be an effective system to detect mercury at very low nanomolar level from aqueous samples. In addition, the nanocomposite exhibited multifunctional properties including efficient photocatalytic and antimicrobial applications, indicates its wide applications in various sectors.

DIRECT BIOLEACHING OF ZINC USING manihot esculenta crantz (cassava) EXTRACT WITHOUT ADDITIVES

The advent and development of new technologies that will provide better yields, cleaner and a safer environment is a global challenge for the researchers. Traditional solvents used in extraction of minerals are at many times hazardous thereby constituting threats to the ecology. The work reports the direct bioleaching of zinc sourced from Abakaliki-Ishiagwu complex zinc sulphide ore deposit. The sphalerite ore is predominant in Zn with other associated metals Pb, Cu, Fe, Ni, Sb, As, Cd, Au, V, Co, Ag, K, Al and Ca. It covers the pre extraction processes of mineral comminution (crushing and grinding); separation by froth flotation; and roasting. Agro-cyanide was extracted from cassava plant (Manihot esculenta Crantz) leaves and was used as leachant without any additive. The result of atomic absorption spectrometry (AAS) analysis of the leached liquor (pregnant solution) shows that lead, copper and iron in addition to Zinc, were obtained from the leached ore roast at 149.25 ppm (Zn), 79.25 ppm (Pb), 0.25 ppm (Cu) and 4.25 ppm (Fe) extraction after 21 days. Elongated contact of ZnO ore is not encouraging for Zn extraction as there is a decline in the quantity of Zn, Fe and Cu as the leaching time (days) increases. The mechanism of the Leach next faction is yet to be fully ascertained, hence the need for further work in the area.

Mineral and trace element composition of the roe and muscle tissue of farmed rainbow trout (Oncorhynchus mykiss) with respect to nutrient requirements: Elements in rainbow trout products

BackgroundDue to excellent nutritional properties of fish and fish products, dietitians recommend their larger share in the diet, for both the prevention and treatment of diet-related diseases. In this context particular attention should be given to fish eggs (roe). The aim of the study was to compare the content of selected minerals and trace elements in the roe and muscle tissue of aquaculture-reared rainbow trout. Moreover, the extent to which an edible portion of 100 g of fish product (roe or fillet) satisfies the requirements for these elements in adult consumers (women and men) and children was determined. MethodsThe research material was represented by 20 farmed rainbow trout females (Oncorhynchus mykiss). In muscle tissue and roe the proximate composition, energy value, and nutritional quality index were examined. Concentrations of K, Na, Ca, Mg, Zn, Fe, Mn and Cu were determined by flame atomic absorption spectrometry analysis. The levels of minerals and trace elements in fish products were used to calculate the percentages of the recommended dietary reference values for adults and children in portion of 100 g. ResultsThe roe had higher content of 7 elements including, Zn (29.40 ± 1.38, 27.74–30.91 mg/kg), Mn (1.66 ± 0.08, 1.55–1.73 mg/kg), Fe (11.17 ± 0.35, 10.75–11.60 mg/kg), Cu (1.24 ± 0.04, 1.21–1.30 mg/kg), Ca (546.90 ± 23.68, 522.02–578.96 mg/kg), Mg (546.97 ± 23.68, 522.02–578.96 mg/kg), Na (403.61 ± 5.53, 397.29–407.57 mg/kg) compared to muscle tissue, respectively, Zn (2.73 ± 0.97, 0.94–3.77 mg/kg, Mn (0.22 ± 0.10, 0.14–0.46 mg/kg), Fe (2.19 ± 1.44, 1.02–5.50 mg/kg), Cu (0.24 ± 0.06, 0.17–0.36 mg/kg), Ca (164.07 ± 71.72, 93.24–306.32 mg/kg), Mg (240.00 ± 73.37, 127.92–316.41 mg/kg), Na (273.37 ± 99.65, 183.93–524.41 mg/kg). In turn, the muscle tissue contained 3 times as much K (5159.87 ± 974.70, 4004.63–6343.91 mg/kg) as the roe (1713.65 ± 58.68, 1643.97–1764.14 mg/kg). The roe covered the recommended nutrition standards (population reference intake, PRI and adequate intake, AI) to a greater extent than the fillet for all analysed trace elements and minerals except K. For children, the contribution of roe to the reference intake of such elements as Mg, Zn, Fe, Mn and Cu was particularly high. Therefore the roe should be considered as a source of Mg for all consumer groups, and as high in Zn for women and children. The suggested portion of fillet and roe provided only 2–3 % of the daily requirement for Na. ConclusionsDespite the differences found, both roe and fillet from rainbow trout are a good source of analysed elements. The results indicate the need to continue research in order to determine the influence of other factors on the content of minerals and trace elements in roe and the possibility of using gonads to enrich other food products with elements.

Phytochemical Contents, Characterization and Elemental Analysis of Pawpaw Leave Extract (Carica papaya)

Traditionally, carica papaya (pawpaw) leaves have been used to cure so many diseases which include infertility. The carica papaya leaves were subjected to phytochemical screening using standard methods, elemental analysis was conducted using AAS (Atomic Absorption Spectrophometry), FTIR was used to elucidate the compounds detected and GC-MS was used for the qualitative and quantitative detection of the bioactive compounds. The results showed that flavonoids, alkaloids, tannins, steroids, saponins and terpenoids were detected. AAS (Atomic Absorption Spectrometry) analysis in mg/kg showed the presence of zinc (26.19mg/kg), chromium (5.22mg/kg), iron (29.17 mg/kg) and manganese (7.92mg/kg) respectively. The functional groups identified in ῡ (cm-1) are 3354 (O-H stretch); 2924, 2853 (C-H stretch); 1736 (C=O stretch); 1619 (C=C stretch), while the result obtained from GC-MS analysis of methanolic extract of Carica papaya leaves revealed Δ -Tocopherol (32.835), γ - Tocopherol (33.671), Vitamin E (34.374), Neryl nitrile (31.817), Curan-17-oic acid, 2, 16-didehydro- 20-hydroxy-19-oxo (30.764). It can be concluded that the Carica papaya leaves extracted with methanol contains some elements such as zinc, iron and manganese and compound such as vitamin E along with the phytochemical. which are require for the treatment of infertility.

Speciation of chromium in beverages and seasoning samples by magnetic solid-phase extraction and microsample injection system flame atomic absorption spectrometry

In this research, a magnetic solid phase extraction based on the use of magnetic polyaniline-polythiophene copolymer (Fe3O4@coPANI-PTH) nanoparticles is applied for chromium speciation from water, beverages and seasoning samples followed by microsample injection system-flame atomic absorption spectrometry(MIS-FAAS) analysis. The selective adsorption of Cr(III) in presence of Cr(VI) by Fe3O4@coPANI-PTH in the pH range of 9.0-10.5 was obtained and the total Cr, after reduction of chromium(VI) to chromium(III) by adding 0.5 mL of concentrated H2SO4 and 10 mL of 5% (w/v) hydroxylamine hydrochloride, was determined. The detection limit, enhancement factor, and repeatability of the optimized method for Cr(III) were calculated to be 1.5 µg L-1, 38.5, and 1.78%, respectively. The method was validated by the analysis of TMDW-500 drinking water and LGC7162 Strawberry Leaves as certified reference materials. The relative error for total chromium was found to be lower than 4.6%. Recoveries were obtained quantitatively using this method (≥95%).

Chemical and mineralogical characterization of weathering products in mine wastes, soil, and sediment from the abandoned Pb/Zn mine in Skikda, Algeria

The Sidi Kamber Zn/Pb mine located 60 km from Skikda is one of the abandoned mining areas of northeastern Algeria for more than 40 years. Currently, this mining area is considered as a real environmental problem. The purpose of this work is to identify and characterize different sources of polymetallic pollution and their impact on the Guenitra dam sediments quality by analyzing the metal content of the weathering products in mine wastes (tailings and waste rock), soil affected by acid mine drainage and Guenitra dam sediments. Moreover, this study aims to determine the mineralogical composition of new compounds occurring in the fine-grained sediments (less than 250 µm) of the mining area. The chemical analysis and the concentration of Fe, Cd, Zn, Cr, Pb, Cu, Mn, Ni, and Hg metals of the studied samples were performed using atomic absorption spectroscopy analysis, inductively coupled plasma optical emission spectrometer, and X-fluorescence ray analysis. The mineralogical composition of all samples was characterized by several techniques such as Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The obtained data were analyzed using multivariate statistical analysis, correlation matrix, hierarchical cluster analysis (HCA), and principal component analysis (PCA). The results showed very high content of Pb, Zn, Cd, Cr, and Hg toxic metals in all samples and suggest taking corrective measures should be taken to reduce the spread of these hazardous elements into the environment. A rehabilitation of the abandoned Sidi Kamber mine should be recommended, as well. The obtained results of HCA and PCA suggest two principal origins of metals pollution: Cu, Mn, Hg, and Pb are derived from anthropogenic sources of mine wastes from the tailings piles, while, Ni, Zn, Cr, and even Fe are derived from lithogenic and anthropogenic sources. Mineralogical characterization results of weathering products in mine wastes, soil, and sediment highlighted the presence of the following minerals: quartz, muscovite, kaolinite, goethite, hematite, lepidocrocite, ferrohexahydrite, and jarosite.

Use and validation of magnetic properties for differentiating nickel hyperaccumulators and non-nickel hyperaccumulators in ultramafic regions

Nickel hyperaccumulators are plants that can absorb a large amount of Ni in their tissues. Nickel hyperaccumulators have a strong potential to be used as bioindicators in mineral explorations. Previous studies show that analysis of magnetic susceptibility has a potential to accelerate the screening of Ni hyperaccumulators. In this study, we investigated the use magnetic characterizations for screening directly Ni hyperaccumulators and non-Ni hyperaccumulators from ultramafic regions. For comparison, the characterization of Ni hyperaccumulators was also performed on Alyssum murale and Alyssum corsicum, which were cultivated on lateritic soils. The metals concentrations in the tissues were determined via inductively coupled plasma optical emission spectroscopy analysis, atomic absorption spectroscopy analysis, and X-ray fluorescence analysis. The magnetic characterizations were conducted by magnetic susceptibility measurement, acquisition of hysteresis curves, and analysis of the thermomagnetic properties. The results showed that the concentration of Ni in A. murale and A. corsicum were correlated to the magnetic susceptibility values. Concurrently, all samples had negative magnetic susceptibility values were non-Ni hyperaccumulators. Two new species of Ni hyperaccumulators were found in Halmahera and Sulawesi and have high potential for use in phytoremediation, phytomining or mineral exploration.

Preparation and evaluation of iron oxide/hydrotalcite intercalated with dodecylsulfate/β-cyclodextrin magnetic organocomposite for phenolic compounds removal

The magnetic adsorbent iron oxide-hydrotalcite modified with the surfactant dodecylsulfate (DS) and β-cyclodextrin (β-CD) was evaluated in the removal of phenol (PHE), p-nitrophenol (PNP) and p-cresol (PCS) from aqueous solution. The magnetic adsorbent was named Fe/HT-DS/β-CD and has the advantage of being easily removed from aqueous solution through application of a magnetic field. The adsorbent was characterized by Infrared Spectroscopy (IR), X-ray diffractometry (XRD), Raman spectroscopy, Scanning Electron Microscopy (SEM), Energy Dispersion Spectroscopy (EDS), Atomic Absorption Spectroscopy (AAS), zeta potential and elemental analysis (CHNS). The effect of pH, dosage, contact time, kinetics, temperature and adsorption thermodynamics were evaluated by phenolic compounds removal. The maximum adsorption capacity of the PHE, PNP and PCS by the adsorbent were 216.08 mg g−1, 255.63 mg g−1 and 272.48 mg g−1, respectively, at 180 min, pH 6 and 25 °C. The thermodynamic parameters indicate that the adsorption is spontaneous and endothermic. This adsorbent showed satisfactory results when applied in the treatment of pulp and paper industry effluent that naturally contains phenol, p-nitrophenol and p-cresol and fortified river water samples.

An ex-situ and in vitro approach towards the bioremediation of carcinogenic hexavalent chromium

Chromium, ranking the second most among toxic heavy metal pollutants in the world, causing respiratory, cardiovascular and renal problems in human beings is under study herein. We examined the biological remediation of the carcinogenic Cr (VI) polluted soils by indigenous yeast isolates. The total element analysis of the treated sample was determined by Energy Dispersion X-ray Micro Analysis (EDXMA). The sample under study was observed to have a high concentration of 458.29 mgKg−1 Cr (VI), determined by Atomic Absorption Spectroscopy (AAS) and DPC analysis. The most tolerant isolate designated as CSR was used for in vitro and ex-situ bioremediation studies of Cr (VI). The isolate achieved significant bioremediation of 86% in vitro and 75.12% in ex-situ method. The optimal conditions for in vitro bioremediation were found to be 28 °C and a pH of 6. The ITS1, 5.8S rRNA and D1, D2 domain of LSU rRNA gene characterization of the isolate CSR illustrated that it belongs to Ustilago genera. The isolate was deposited in NCBI GenBank as Ustilago sp. CSR (KY284846). Although, Ustilago is generally a pathogenic fungus, our study opens up the scope of using Ustilago spp. for bioremediation of the carcinogenic heavy metal Chromium.

Stress Protective Effect of Rhododendron arboreum Leaves (MEL) on Chromium-Treated Vigna radiata Plants

Oxidative stress due to hexavalent chromium [Cr(VI)] in Vigna radiata seedlings, and stress amelioration with treatment of methanol extract of Rhododendron arboreum leaves was observed in the present study by analyzing growth parameters, stomatal morphology, malondialdehyde (MDA) content, histological analysis, pigment contents, Cr metal uptake, elemental analysis, and antioxidant analysis. Chromium treatment resulted in the decline of root length, shoot length, fresh weight, and dry weight. Scanning electron microscopic studies revealed that Cr treatment altered the stomatal structure. As compared to control plants, MDA content increased by 80.1% in Cr-treated plants. Histological analysis with confocal microscope confirmed the nuclear damage, membrane damage, enhanced H2O2 accumulation, and decline in pigment concentration. Atomic absorption spectrometry analysis revealed an accumulation of 43.3% Chromium in the plant tissues and decreased concentration of essential elements as consequences of Cr treatment. The methanol extract of R. arboreum leaves (MEL) alleviated Cr stress in Vigna radiata seedlings by restoring normal growth, stomatal structure, and pigment contents, as well as essential elements. Reduction in H2O2 accumulation, reduced MDA content by 29.2%, and decline in Cr accumulation to 32.8% was observed after MEL supplementation to Cr-stressed plants. Decreased nuclear and membrane damage along with increased lipid-soluble as well as water-soluble antioxidants after MEL application in Cr-stressed plants are further symptoms of stress amelioration properties of Rhododendron leaves.

Reactivity of (3-aminopropyl)trimethoxysilane with cellulose

Reactivity of (3-aminopropyl)trimethoxysilane with cellulose. The paper presents the results of tests for the reactivity of (3-aminopropyl)trimethoxysilane (APTMOS) with cellulose. The cellulose was treated with aqueous ethanolic solution of silane in two concentration: 5% and 20%. The reactivity of APTMOS with cellulose was analysed using instrumental methods: attenuated total reflectance Fourier transform infrared spectroscopy, atomic absorption spectrometry and elemental analysis. In the FTIR spectra of silane-treated cellulose, the bands of Si-O, Si-C and N-H bonds were detected. The analysis of silicon and nitrogen concentration in treated cellulose confirmed the presence of silane in cellulose structure. The presented results indicate that APTMOS forms chemical bonds with cellulose.

The influence of coating with aminopropyl triethoxysilane and CuO/Cu2O nanoparticles on antimicrobial activity of cotton fabrics under dark conditions

AbstractA novel impregnation process for the fabrication of cotton nanocomposite with strong antimicrobial activity against antibiotics‐resistant bacteria and yeast was developed. The impregnation process includes the sol–gel treatment of fabric with (3‐aminopropyl)triethoxysilane in the first step, and synthesis of the CuO/Cu2O nanoparticles (NPs) on the fabric surface in the second step. The in situ synthesis of the CuO/Cu2O NPs was based on the adsorption of Cu2+‐ions by the introduced amino groups of the sol–gel coating. The adsorbed Cu2+‐ions are subsequently reduced in the alkaline solution of NaBH4. X‐ray diffraction measurements confirmed the formation of CuO/Cu2O NPs. Scanning electron microscopy and atomic absorption spectrometry analyses indicate that the particle size, agglomeration, and amounts of synthesized NPs were highly affected by the initial concentration of CuSO4 solution. The toxicity of nanocomposites to human keratinocytes (HaCaT) and antimicrobial activity against Gram‐negative Escherichia coli ATCC 25922, E. coli ATCC BAA 2469, and Klebsiella pneumoniae ATCC BAA 2146, and Gram‐positive bacteria Staphylococcus aureus ATCC 25923, S. aureus ATCC 43300 and yeast Candida albicans ATCC 24433 strongly depended on the copper content. In addition to excellent antimicrobial activity, controlled release of Cu2+‐ions from the fabrics into physiological saline solution was obtained.

Glucose regulates hypoxia-induced NLRP3 inflammasome activation in macrophages.

Although the intimate linkage between hypoxia and inflammation is well known, the mechanism underlying this linkage has not been fully understood. Nucleotide-binding oligomerization domain-like receptor (NLR) family pyrin domain containing 3 (NLRP3) inflammasome is an intracellular multiprotein complex that regulates interleukin-1β (IL-1β) secretion and pyroptosis, and is implicated in the pathogenesis of sterile inflammatory diseases. Here, we investigated the regulatory mechanism of NLRP3 inflammasome activation in response to hypoxia in macrophages. Severe hypoxia (0.1% O2 ) induced the processing of pro-IL-1β, pro-caspase-1, and gasdermin D, as well as the release of IL-1β and lactate dehydrogenase in lipopolysaccharide (LPS)-primed murine macrophages, indicating that hypoxia induces NLRP3 inflammasome-driven inflammation and pyroptosis. NLRP3 deficiency and a specific caspase-1 blockade inhibited hypoxia-induced IL-1β release. Hypoxia-induced IL-1β release and cell death were augmented under glucose deprivation, and an addition of glucose in the media negatively regulated hypoxia-induced IL-1β release. Under hypoxia and glucose deprivation, hypoxia-induced glycolysis was not driven and subsequently, the intracellular adenosine triphosphates (ATPs) were depleted. Atomic absorption spectrometry analysis showed a reduction of intracellular K+ concentrations, indicating the K+ efflux occurring under hypoxia and glucose deprivation. Furthermore, hypoxia and glucose deprivation-induced IL-1β release was significantly prevented by inhibition of K+ efflux and KATP channel blockers. In vivo experiments further revealed that IL-1β production was increased in LPS-primed mice exposed to hypoxia (9.5% O2 ), which was prevented by a deficiency of NLRP3, an apoptosis-associated speck-like protein containing a caspase recruitment domain, and caspase-1. Our results demonstrate that NLRP3 inflammasome can sense intracellular energy crisis as a danger signal induced by hypoxia and glucose deprivation, and provide new insights into the mechanism underlying hypoxia-induced inflammation.

Reusability study of zirconia catalyst toward photocatalytic degradation of remazol brilliant blue dye

The regeneration and reusability study of EGZrO2 catalyst toward remazol brilliant blue (RBB) dye was carried out at specific optimum conditions. The overall degradation rate trends after seventh cycles shows that the photocatalytic process is stable from the first run at 99.8% and final seventh cycle at 83%, with only just small decreases rate about less than 17%. It is suggested that heat treatment during calcination at every cycle induced the catalyst aggregation and may also attribute during scouring of catalyst surface. No metal ions dissolution is detected by atomic absorption spectroscopy (AAS) analysis showing that the catalyst is more stable and also excellence photoresponse in visible light regions.