Mercuric Oxide Research Articles

Appropriate Condition to Generate Yellow Precipitates with Fehling Reaction

Appropriate Condition to Generate Yellow Precipitates with Fehling Reaction

Selenite bioreduction with concomitant green synthesis of selenium nanoparticles by a selenite resistant EPS and siderophore producing terrestrial bacterium.

Environmental bacterial isolates play a very important role in bioremediation of metals and toxic metalloids. A bacterial strain with high selenite (SeO32-) tolerance and reducing capability was isolated from electronic waste dump site in Banaras Hindu University, Varanasi, India. Based on 16S rRNA sequencing and BLAST search, this bacterial isolate was identified as Bacillus paramycoides and designated as strain MF-14. It tolerated Sodium selenite up to 110 mM when grown aerobically in LB broth and reduced selenite into elemental selenium (Se0) significantly within 24h with concomitant biosynthesis of selenium nanoparticles as clearly revealed by brick red precipitate and specific surface plasmon resonance peak at 210nm using UV-Visible spectrophotometer. Scanning electron microscopy (SEM) analysis of this bacterial strain exposed to 1mM and 5 mM selenite also demonstrated morphological alterations as cell enlargement due to accumulation and bioprecipitation of elemental selenium (Se0). The FTIR analysis clearly demonstrated that functional groups present on the surface of biogenic selenium nanoparticles (SeNPs) play a significant role in the stabilization and capping of SeNPs. Furthermore, these SeNPs were characterized using spectroscopic analysis involving Dynamic light scattering, zeta potential, XPS, FTIR, XRD and Raman spectroscopy which clearly revealed particle size 10-700nm, amorphous nature, stability as well as it's oxidation state. The biochemical studies have demonstrated that membrane bound reductase enzyme may be responsible for significant reduction of selenite into elemental selenium. Therefore, we may employ Bacillus paramycoides strain MF-14 successfully for bioremediation of selenite contaminated environmental sites with concomitant green synthesis of SeNPs.

Tissue Tropism of H9N2 Low-Pathogenic Avian Influenza Virus in Broiler Chickens by Immunohistochemistry

The H9N2 subtype of low-pathogenic avian influenza viruses (LPAIV) is a widespread pathogen of poultry that can also infect humans. The characterization of viral infections is a complex process, involving clinical, pathological, and virological investigations. The aim of this study was to adapt and optimize an immunohistochemical (IHC) technique developed for LPAIVs specifically for the detection of H9N2 virus antigens in infected tissues. Twenty-one-day-old broiler chickens were inoculated with three different strains of H9N2 virus by different infection routes (i.e., intranasal-intratracheal and intravenous) or co-infected with infectious bronchitis virus (IBV) and observed for 11 days post infection. The suggested IHC protocol was modified: (i) DAB (diamino-benzidine) was substituted with AEC (3-amino-9-ethyl carbazole) as chromogen; and (ii) indirect two-step immune reactions of monoclonal primary and peroxidase-labeled anti-mouse secondary antibodies were used instead of avidin-biotin complexes. Avian influenza virus antigen appears as a red precipitate in the nuclei of affected cells but can also be identified in the cytoplasm. Mild hyperemia and congestion were observed in the trachea, air sac, and lungs of the challenged birds, and fibrinous exudate was found at the bifurcation in a few cases. Neither gross pathological nor IHC lesions were found in the control group. Using the optimized protocol and an associated scoring scheme, it was demonstrated that the H9N2 strains tested exhibited respiratory and urinary tract tropism irrespective of the route of inoculation. On day 5, viral antigen was detected in the respiratory tract and kidney in 30-50% of the samples. On day 11, no IHC signal was observed, indicating the lack of viral replication. Slight differences in viral antigen expression were found between the different H9N2 virus strains, but, in contrast to highly pathogenic avian influenza (HPAI), no viral antigen was detected in the brain and pancreas. Thus, IHC can be considered as an informative, visual addition to the toolkit for the characterization of H9N2 LPAIV infections.

Understanding the processes of thickening and filtration of yellow cake slurry (ammonium polyuranate) generated by in-situ uranium leaching sites

One of the key stages in the in-situ leaching of uranium includes thickening of yellow cake slurry to obtain washed uranium concentrate. Russian in-situ leaching sites tackle this by using membrane filter presses. In spite of their high performance, filter presses have one major drawback – the filtration is done periodically. This paper describes the results of a laboratory study suggesting that, together with membrane filter presses, continuous band vacuum filters could also be used in this application. The yellow cake slurry obtained after precipitation of ammonium polyuranate from Dalur JSC’s eluates has the density of 1060–1065 kg/m3. In laboratory conditions, the slurry was thickened by adding 1 g/dm3 of Praestol 2530 slurry. The settling rate was 5.4 m/h, the thickening performance – 2.8 t/(m2.day). The resultant thickened product with a density of 1600 kg/m3 was filtered in a band filter with a three-stage counter-current washing cycle at a fresh water flow rate of 1 m3/t solid and a vacuum of –49 kPa. The process resulted in an average filtration performance of 8–9 t/(m2.day) and a 17–18 mm thick washed precipitate with 41–43% humidity. The duration of the overall filtration and washing cycle was 110–140 sec. The maximum concentration of sulphate-ion in the washed and dried yellow cake precipitate did not exceed 2.0%, which is significantly lower than the 4% allowed. It is noted that, if necessary, these indicators can be improved by raising the rinse water flow rate.

MCQ corner

1. Selenocysteine is coded by UGA UAG UAA AUG Ans: A. UGA Explanation Selenocysteine (SeCys/SeC) is the 21st amino acid and is found in thioredoxin reductase, glutathione peroxidase, 5’-deiodinase, and selenoprotein P. It is an exceptional case where a stop codon codes for an amino acid. The other stop codons are UAA and UAG. The ability of the protein synthetic apparatus to identify a selenocysteine-specific UGA codon involves the selenocysteine insertion element, a stem-loop structure in the untranslated region of the mRNA.[1] 2. A child with diarrhea for 2 days came to your out-patient department (OPD). On examination, the signs of dehydration were marked and the child was treated with oral rehydration solution (ORS). Glucose absorption was facilitated by which receptors? SGLT1 SGLT2 GLUT4 Sodium–hydrogen antiporter Ans: A. SGLT1 Explanation Absorption of glucose from the intestinal lumen to intestinal cells is by the cotransport mechanism. It is an active transport system and can transport against the concentration gradient.[2] 3. Skeletal derivative of the second pharyngeal arch is Malleus Incus Stapes Maxilla Ans: C. Stapes Explanation Maxilla, malleus, and incus are derived from the first arch.[3] 4. Blastocyst makes contact with a uterus on <3 days 5–7 days 8–11 days 15–16 days Ans: B. 5–7 days Explanation Contact of the blastocyst with endometrium occurs at the time of implantation. Implantation occurs at around 5-7 days.[4] 5. The father of antiseptic surgery is Louis Pasteur Robert Koch Julius Petri Joseph Lister Ans. D. Joseph Lister Explanation Louis Pasteur – the father of microbiology, Robert Koch – the father of microbiology (with Louis Pasteur), and the father of medical bacteriology, Julius Petri – invented the Petri dish.[5] 6. Following were the findings in a Glucose tolerance test (GTT). Fasting blood glucose <75 mg/dl; all blood samples show low blood glucose; urine glucose – nil. The possible diagnosis is Alimentary glycosuria Diabetes mellitus Hypopituitarism Diabetes insipidus Ans. C. Hypopituitarism Explanation In alimentary glycosuria, there will be a peak in the first sample after glucose load and sugar will appear in urine. In diabetes mellitus, fasting and the next two samples will show higher values than the normal reference range and the sample does not return to baseline at the end of the test. In hypopituitarism, there is hypoglycemia and the patient feels fatigued and stressed. In diabetes insipidus, GTT is mostly unaffected.[6] 7. A 10-year-old boy with a history of atopy presented with seasonal recurrent bilateral conjunctivitis and complained of blurred vision for the past 1 week. On lid eversion, giant papillae were seen. All of the following could be seen by slit-lamp examination except: Vascular pannus and punctate epithelial erosions involving the superior cornea. An oval epithelial ulceration with underlying stromal opacification in the central cornea Limbal follicles Conjunctival symblepharon Ans. D. Conjunctival symblepharon Explanation A conjunctival symblepharon is seen in the case of autoimmune disorders such as Sjogren’s syndrome, sarcoidosis, lichen planus, granulomatosis with polyangiitis, etc.[7] 8. Which of the following breast lesion is a noninvasive malignancy? Tubular carcinoma and mucinous carcinoma Intraductal carcinoma of the comedo type Infiltrating ductal carcinoma and lobular carcinoma Medullary carcinoma, including atypical medullary lesions Ans. B. Intraductal carcinoma of the comedo type Explanation A comedo-type ductal carcinoma in situ (DCIS), also known as comedocarcinoma insitu, is the high-grade subtype of DCIS. It completely fills and dilates the ducts and lobules in terminal duct lobular units with plugs of high-grade tumor cells with central necrosis “comedonecrosis.”[8] 9. In patients who develop a documented episode of deep-vein thrombosis, the most significant long-term sequelae are: Claudication Recurrent foot infections Development of stasis ulcer Pulmonary embolization Ans. C-Development of stasis ulcer Explanation Chronic symptoms may occur after 6 weeks or beyond. Pulmonary embolization is the most common complication but is seen as an acute complication.[9] 10. Identify the test from the diagram. Rothera’s test Benedict’s test Barfoed’s test Seliwanoff’s test Ans. A. Rothera’s testFigure 1: Purple permanganate coloured ring [Ferro-penta cyanine complex] at the junction of two fluidsExplanation Rothera’s test was done to identify the presence of ketone bodies in a urine sample. Benedict’s test will contain a green/yellow/orange/brick red precipitate at the bottom. Barfoed’s test has a red scum at the top of the fluid and a little red precipitate at the bottom. Seliwanoff’s test will have a cherry red color.[10] Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.

Effects of the fermentation process on the selenite metabolism and selenium incorporation and speciation in a probiotic Bifidobacterium longum.

The influence of the fermentation process on selenite metabolism by a probiotic Bifidobacterium longum DD98 (B. longum DD98), and its consequent enrichment in selenium (Se) were studied. The effects of sodium selenite (Na2SeO3) concentration (18-400 μg/mL), feeding time (12, 16, and 24 h), and fermentation stage (secondary and tertiary fermentation) were evaluated by measuring i) the total Se content and its distribution between the water-soluble metabolome fraction and the water-insoluble fraction; ii) the total concentrations of the two principal Se-compounds produced: selenomethionine (SeMet) and γ-glutamyl-selenomethionine (γ-Glu-SeMet), and iii) the speciation of Se in the metabolite fraction. The results revealed that the fermentation process notably changed the Se incorporation into metabolites (γ-Glu-SeMet and free SeMet) and proteins (bound-SeMet) in B. longum DD98. In particular, the production of SeMet was negatively correlated to that of γ-Glu-SeMet when no red precipitate was seen in the bacteria. The study offers a tool for the control of the optimization of the fermentation process towards the desired molecular speciation of the incorporated Se and hence contributes to the production of Se-enriched probiotics with good qualities and bioactivities.

Synthesis, physical, optical and gamma radiation shielding capacities of novel mercuric-sodium-lead-borate glasses

The influence of mercuric oxide (HgO) on structural, physical, optical, and radiation shielding capacities of newly developed glasses with nominal compositions (55-x)B2O3·10SrF2·25PbO·10Na2O·xHgO: x = 0, 2, 4, 6, and 8 mol% has been investigated. Hg-glasses were synthesized by the traditional melt quenching technique and coded as Hg0, Hg2, Hg4, Hg6, and Hg8, respectively. The amorphous nature of Hg-glasses was confirmed via XRD measurements. Density of the prepared glasses was measured via Archimedes' method and it was increased from 4.59 g/cm3 for Hg0 sample to 5.20 g/cm3 for Hg8 sample. The values of optical band gap (Eg) were reduced with the insertion of HgO in Hg-glass network. The direct (Eg) was changed from 3.52 to 3.21 eV, while the indirect one change from 2.47 to 2.14 eV. Urbach's energy (Eu) was varied from 0.737 to 1.544 eV and refractive index was improved from 2.197 to 4.077 at wavelength λ=500 nm. The average oscillator strength (So) of Hg-glasses was changed from 2.885×10-5 (nm)2 to 11.078 × 10−5 (nm)2. The Hg8 glass possessed the maximum values of mass attenuation coefficient (MAC)Phy-X/PSD among all Hg-glasses. The values of (MAC)Phy-X/PSD at (0.015 MeV, 15 MeV) were (0.037, 53.675), (0.38, 58.123), (0.039, 62.352), (0.40, 66.376), and (0.40, 70.210) cm2/g for Hg0, Hg2, Hg4, Hg6, and Hg8 glasses, respectively. The variation of the effective atomic number (Zeff)Phy-X/PSD of the prepared Hg-glasses has a similar trend of (MAC)Phy-X/PSD. The half value layer (HVL)Phy-X/PSD for various samples followed the trend; ((HVL)Phy-X/PSD)Hg0 > ((HVL)Phy-X/PSD)Hg2 > ((HVL)Phy-X/PSD)Hg4 > ((HVL)Phy-X/PSD)Hg6 > ((HVL)Phy-X/PSD)Hg8. However, the reduction of (HVL)Phy-X/PSD with increasing HgO concentration in the glassy system increase its ability to shield against the incident photons. The prepared Hg-glasses with improved physical and optical properties can be used in various optical applications and are superior as radiation shielding materials than seven kinds of concrete OC, HSC, ILC, BMC, IC, SSC, SMC, and RS-253-G18 glasses.

Observation and Characterization of the Hg-O Diatomic Molecule: A Matrix-Isolation and Quantum-Chemical Investigation.

Mercuric oxide is a well-known and stable solid, but the diatomic molecule Hg-O is very fragile and does not survive detection in the gas phase. However, laser ablation of Hg atoms from a dental amalgam alloy target into argon or neon containing about 0.3 % of 16 O2 or of 18 O2 during their condensation into a cryogenic matrix at 4 K allows the formation of O atoms which react on annealing to make ozone and new IR absorptions in solid argon at 521.2 cm-1 for Hg-16 O or at 496.4 cm-1 for Hg-18 O with the oxygen isotopic frequency ratio 521.2/496.4=1.0499. Solid neon gives a 529.0 cm-1 absorption with a small 7.8 cm-1 blue shift. CCSD(T) calculations found 594 cm-1 for Hg16 O and 562 cm-1 for Hg18 O (frequency ratio=1.0569). Such calculations usually produce harmonic frequencies that are slightly higher than the anharmonic (observed) values, which supports their relationship. These observed frequencies have the isotopic shift predicted for Hg-O and are within the range of recent high-level frequency calculations for the Hg-O molecule. Spectra for the related mercury superoxide and ozonide species are also considered for the first time.

PENERAPAN METODE SPEKTROFOTOMETRI SERAPAN ATOM (SSA) DALAM MENGANALISIS LOGAM MERKURI (Hg) PADA KRIM PEMUTIH WAJAH

Whitening cream is a mixture of chemicals and or other ingredients with properties that can fade dark spots on the skin. Whitening cream must be safe and must not contain harmful ingredients such as heavy metal mercury because its toxicity to the organs of the kidneys, nerves, and brain is very strong, so its use is prohibited in cosmetic preparations. The purpose of this study was to determine the levels of metallic mercury (Hg) contained in the preparation of facial whitening creams circulating in Sei Sikambing Market, Medan. The sample used in this study was a facial whitening cream that was not registered with BPOM. The method used to determine mercury levels is qualitatively using color reagents and quantitatively using AAS (Atomic Absorption Spectrophotometry). The results obtained were from 2 samples of facial whitening cream that were used positively for heavy metal mercury (Hg) characterized by the formation of a red-orange precipitate with KI reagent, yellow precipitate by NaOH reagent, white precipitate by HCl reagent. The results of the analysis showed that the highest Hg metal content in the sample with code E was 5.0241 ± 0.4064 g/g. The conclusion of this study is that two samples were positive for mercury, where the use of mercury has been prohibited by BPOM.

ANALISIS KADAR ASAM ASETAT HASIL FERMENTASI ECO-ENZYME DARI KULIT JERUK BALI (Citrus maxima Merr.) DAN POTENSINYA SEBAGAI ANTIOKSIDAN DENGAN METODE ALKALIMETRI DAN DPPH

The garbage problem is a very important problem because it has the potential to damage the balance of the environmental ecosystem. Many studies have been carried out on the content of active compounds in grapefruit peel, but there are differences in sampling locations, types of solvents for extraction, differences in treatment and testing. In the discovery of Eco-enzyme fermentation solution product, Dr. Rosukon Poompanvong to help local farmers to obtain better yields while being friendly to the environment. Eco-Enzyme is a popular fermented fruit peel organic waste which has been developed because it is very practical, economical, and environmentally friendly. Utilization of fruit peels into Eco-Enzyme is an evolution of science in the health sector. This study aims to determine the Eco-Enzyme fermentation process from pomelo peel and Eco-Enzyme acetic acid levels and their potential as antioxidants with experimental research using Eco-Enzyme sample solution with FeCl3 solution as a qualitative test indicator for Eco-Enzyme samples. Quantitative test using 1-2 drops of Eco-Enzyme sample solution 0,1 M NaOH standard solution and phenolphthalein indicator solution in alkalimetric titration and DPPH method with DPPH solution using UV-Vis spectrophotometer. From the results of qualitative research, the results of Eco-Enzyme fermentation are in the form of a light brown solution, have a brick red precipitate, and there is a brick red precipitate. The results of quantitative research on alkalimetric titration of Eco-Enzyme fermentation, there is an acetic acid level of 7.5% per one gram of pomelo peel, and the DPPH method on the fermented Eco-Enyme solution with an IC50 value of 9.418075752 ppm, which means it has very strong antioxidant potential. Eco-enzyme sample solution has acetic acid level of 7,5% per one gram of pomelo peel and has very strong antioxidant potential

A critical review on Gandhakadya malahara

Malahara is a potent pharmaceutical preparation for external application (Bahya Kalpana) which has Siktha Taila (mixture of sesame oil and bee-wax), Sathadhoutha Ghrita, Ghrita (ghee) as the base. It is an ointment preparation which includes herbal and mineral contents depending upon the usage. Mala-hara kalpanas are very much useful in skin disorders. Malahara has proper-ties like snehana (unctuousness), ropana (healing), lekhana (scrapping) and varnya (colouring) depending upon the drugs used in the preparation. A num-ber of Malahara Kalpanas have been mentioned in Rastarangini. Gandhakadhya Malahara is one among them mentioned in Gandhaka Vijnanam Tarangam. It is a herbo-mineral formulation comprises of Siktha taila (mixture of sesame oil and beeswax) as a base and Shudha Gandhaka (Purified Sulphur), Shudha Girisindura (Purified Mercuric Oxide), Shudha Tankana (Purified borax) are as other ingredients. Gandhakadhya malahara is intended for external application in various dermatological problems. It is specially indicated for severe Pama (a type of skin condition) as per Rasa-tarangini.

ANALISIS VITAMIN C PADA MINUMAN KEMASAN UNTUK MENINGKATKAN KEKEBALAH TUBUH PADA MASA PANDEMI COVID-19

Corona virus disease (COVID-19) is an infectious disease caused by the SARS-CoV-2 virus which causes symptoms of fever, cough and diarrhea, thereby lowering the body's immunity. One way to improve the human immune system is to consume vitamin C. Vitamin C as an antioxidant that can improve the immune system in humans. This study aims to analyze the content of vitamin C in packaged drinks, namely, Hemaviton C1000 and Fanta Orange flavor. This research method is a qualitative test by looking at the color changes that occur using Benedict's reagent and AgNO3 powder. The results of the qualitative test of vitamin C in packaged C drinks, namely Hemaviton C1000 and Fanta with Orange flavor using Benedict's reagent and AgNO3 powder, respectively, were brick red precipitate and black precipitate which indicated the presence of vitamin C.

Dissociation of Mercuric Oxides Drives Anomalous Isotope Fractionation during Net Photo-oxidation of Mercury Vapor in Air.

The atmosphere is the primary medium for long-distance transport and transformation of elemental mercury (Hg), a potent neurotoxin. The recent discovery of mass-independent fractionation (MIF) of even-mass Hg isotopes (even-MIF, measured as Δ200Hg and Δ204Hg) in the atmosphere is surprising and can potentially serve as a powerful tracer in understanding Hg biogeochemistry. Far-ultraviolet (UVC) light-induced gas-phase reactions have been suspected as a likely cause for even-MIF, yet the mechanism remains unknown. Here, we present the first experimental evidence of large-scale even-MIF caused by UVC-induced (wavelength: 254 nm) Hg oxidation in synthetic air at the pressure (46-88 kPa) and temperature (233-298 K) resembling those of the lower atmosphere. We observe negatively correlated Δ200Hg and Δ204Hg signatures with values as low as -50‰ and as high as 550‰, respectively, in the remaining atomic Hg pool. The magnitude of even-MIF signatures decreases with decreasing pressure with the Δ200Hg/Δ204Hg ratio being similar to that observed in global precipitation. This even-MIF can be explained by photodissociation of mercuric oxides that are photochemically formed in the UVC-irradiated Hg-O2 system. We propose that similar processes occurring in the atmosphere, where mercuric oxide species serve as intermediates, are responsible for the observed even-MIF in the environment.

Thermochemical study of Cr(VI) sequestration onto chemically modified Areca catechu and its recovery by desorptive precipitation method

A new biosorbent for Cr(VI) sequestration was investigated from betel nut waste (BNW), Areca catechu, by H2SO4 charring. Aqueous insolubility and Cr(VI) uptake capacity of native BNW were potentially improved after H2SO4 modification due to cross-linking reaction of betel nut cellulose, thereby creating suitable complexation sites for Cr(VI) ion removal. Langmuir isotherm and pseudo second order (PSO) kinetic models described well with the experimental data. A trace amount of Cr(VI) was effectively removed below the safe drinking water standard (WHO, 0.05 mg/L) using charred BNW (CBNW). The negative value of ΔG° evaluated for all the temperatures suggested the spontaneous nature of Cr(VI) sequestration and positive value of ΔH° (42.43±0.13 kJ/mol) confirmed an endothermic reaction. Co-existing NO3−, Cl−, Na+ and Zn2+ ions showed negligible interferences, whereas SO42− and PO43− notably reduced Cr(VI) uptake capacity of CBNW. More than 98% of adsorbed Cr(VI) was desorbed using 1M NaOH solution. A light yellow precipitate of BaCrO4 was recovered from the desorbed solution after precipitation with BaCl2 solution. Therefore, the CBNW biosorbent investigated in this work is expected to be a promising material for Cr(VI) sequestration and its recovery from polluted water.

Dinuclear terbium(III) complexes based on substituted aliphatic and aromatic acids derivatives: Synthesis and photophysical studies

The formation of 3-((9R,10S,11R,15S)-12,14-dioxo-9,10-dihydro-9,10-[3,4]epipyrroloanthracen-13-yl)propanoic acid (HL1) and 3-((9R,10S,11R,15S)-12,14-dioxo-9,10-dihydro-9,10-[3,4]epipyrroloanthracen-13-yl)benzoic acid (HL2) were achieved from the reaction between Diels-Alder adduct of anthracene and maleic anhydride with β-alanine and 3-aminobenzoic acid, respectively. Leaving HL1 and HL2 with terbium(III) nitrate in a mixture of water:acetone resulted the formation of pale yellow precipitate. Subsequent recrystallization of these crude products in dimethyl sulfoxide resulted the formation of pale yellow crystals, determined to be [Tb2(μ-L1)2(L1)4(H2O)3((CH3)2SO)3]‧(CH3)2SO‧8H2O (1) and [Tb2(μ-L2)2(L2)4(H2O)2((CH3)2SO)2]‧2H2O (2), respectively, from single crystal X-ray diffraction data. In both dinuclear complexes, all terbium(III) ions display a square antiprism geometry with [TbO8] core. Both complexes present a characteristic terbium green emission once irradiated with UV-light corresponding to the 5D4→7F5 transition.

Glassy Carbon Electrodes Decorated with HgO/CNT Nanocomposite and Modified with a Conducting Polymer Matrix for Enzyme‐Free Ascorbic Acid Detection

AbstractIn an alkaline solution, mercuric oxide decorated carbon nanotube nanocomposites (HgO.CNT NCs) were manufactured utilizing an uncomplicated wet‐chemical approach. Ultra‐Violet spectroscopy (UV‐Visible), Fourier Transform Infra‐red spectroscopy (FTIR), Powder X‐ray Diffraction (XRD), X‐ray Photo‐electron Spectroscopy (XPS), and Field Emission Scanning Emission Microscopy (FESEM), X‐ray Electron Dispersive Spectroscopy (XEDS) techniques were applied to examine the HgO.CNT NCs that had been prepared. Ascorbic acid sensor was developed upon light coating of HgO.CNT NCs on polished Glassy carbon electrode (GCE) modified with nafion (Nf). Analytical performance of the selected ascorbic acid sensor was achieved such as sensitivity, Limit of quantification (LOQ), Limit of detection (LOD), Linear dynamic range (LDR), extended reliability, interference effect experimentation, and actual sample inspection using a consistent current‐voltage approach. Calibration curve of the suggested sensor was observed to be linear (R2=0.9957) throughout a broad range of ascorbic acid concentrations (100.0 pM∼100.0 mM) at a voltage of 0.8 V. The calibration curve yielded analytical parameters such as sensitivity (632.91 pAμM−1cm−2), LOQ (255.0 pM), LOD (76.50 pM), and LDR (100.0 pM ∼1.0 mM) for the proposed ascorbic acid sensor (GCE/HgO.CNT NCs/Nf). The wet‐chemical synthesis of HgO.CNT NCs is a good development of nanocomposite‐oriented sensor advancement in medical sciences with non‐enzymatic detection of biological substances. This proposed sensor applied to selective ascorbic acid detection in biological samples and obtained logical outcomes.

Ultrasmall Superparamagnetic Iron Oxide Nanoparticles Synthesized by Micellar Approach as a Potential Dual-Mode T1-T2 Contrast Agent

Purpose: A micellar approach is used to synthesize Ultrasmall Superparamagnetic Iron Oxide Nanoparticles (USPIONs) with an average diameter of 3.4±0.5 nm, suitable for dual-mode T1-T2 contrast agents. Methods: Micelles with 3.8 nm, measured by dynamic light scattering, were obtained by self-organizing the surfactant iron(III) dodecyl sulfate (IDS) in 1-octanol. IDS was prepared by replac-ing Na+ cation in sodium dodecyl sulfate molecule, and its critical micelle concentration (CMC) was measured by electrical conductivity. The USPIONs were synthesized in a biphasic system: IDS in octanol (55% above the CMC) and water containing NaBH4. Results: A yellow precipitate is immediately formed at the water/alcohol interface, rapidly changes to a black one, and transfers to the aqueous phase. The magnetite phase was confirmed by X-ray diffraction and Mössbauer spectroscopy. The magnetic behavior shows a major paramagnetic char-acter with a weak ferromagnetic component at 5 K, the latter attributed to the interparticle couplings below its blocking temperature (TB = 35 K). The particles were coated with carboxymethyl dextran, showing an isoelectric point of 2.7 with electrokinetic potential around -30 mV in the physiological pH range. Magnetic relaxation measurements showed relaxivity values r1 = 0.17 mM-1 s-1 and r2 = 1.73 mM-1 s-1 (r2/r1 = 10) in a 3T field. These values infer that the ultrasmall size affects the interac-tions with the protons of the nearby water molecules. The r2 value decreases because the core mag-netization decreases with size; r1 intensifies due to the high surface. Conclusion: The results show a system with high colloidal stability, non-cytotoxic, and potential application as T1-T2 dual-mode contrast agents.

Diversity and biogenesis contribution of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits.

Microbial sulfate reduction, a vital mechanism for microorganisms living in anaerobic, sulfate-rich environments, is an essential aspect of the sulfur biogeochemical cycle. However, there has been no detailed investigation of the diversity and biogenesis contribution of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits. To elucidate this issue, soil samples from representative abandoned realgar deposits were collected. Microcosm assays illustrated that all three samples (2-1, 2-2, and 2-3) displayed efficient sulfate and As(V)-respiring activities. Furthermore, a total of 28 novel sequence variants of dissimilatory sulfite reductase genes and 2 new families of dsrAB genes were successfully identified. A novel dissimilatory sulfate-reducing bacterium, Desulfotomaculum sp. JL1, was also isolated from soils, and can efficiently respiratory reduce As(V) and sulfate in 4 and 5days, respectively. JL1 can promote the generation of yellow precipitates in the presence of multiple electron acceptors (both contain sulfate and As(V) in the cultures), which indicated the biogenesis contribution of sulfate-reducing bacteria to the realgar mine. Moreover, this area had unique microbial communities; the most abundant populations belonged to the phyla Proteobacteria, Chloroflexi, and Acidobacteriota, which were attributed to the unique geochemistry characteristics, such as total organic carbon, total As, NO3-, and SO42-. The results of this study provide new insight into the diversity and biogenesis contributions of sulfate-reducing bacteria in arsenic-contaminated soils from realgar deposits.

A rapid spectrophotometric method to identify inhibitors of human erythropoiesis

Erythropoiesis is a complex physiological process by which erythroid progenitors proliferate and differentiate into nonnucleated red blood cells. Several methods can be used to monitor in vitro the differentiation of erythroid precursors, and hence the toxic effects of drugs, chemicals, or pollutants. One of the most commonly available assay of erythropoiesis is the microscopic observation of differentiated cells after benzidine staining, which forms a blue complex with hemoglobin. However, this method is laborious and does not provide accurate results since it heavily relies on the reader's interpretation. Moreover, benzidine is a carcinogen and a highly reactive molecule which forces the reader to microscopically count differentiated and non-differentiated cells within a short time frame (5 min).Here we have developed a simple, inexpensive, in-vitro spectrophotometric assay to measure erythroid differentiation using K562 cell line as a model. Materials needed included 96-well round-bottomed microplates and a microplate reader. Remarkably, carcinogenic benzidine was replaced by its isomeric tetramethyl derivative, the 3,3′, 5,5′- tetramethylbenzidine (TMB), which presents several advantages: it is cheap, not mutagenic and a ready-to-use chromogenic substrate. A small volume (50 μl) of TMB added to the samples forms a blue complex in 15 min, and the reaction can be easily stopped and stabilized by the addition of H2SO4. The yellow precipitate is then solubilized, and the absorbance is measured at 450 nm. In addition, the suitability of the assay to determine the effects of compounds on erythroid differentiation was further tested with known inhibitors (artemisinin derivatives) of K562 differentiation.Overall, the reported methodology permits to measure in an accurate and reproducible manner the K562 differentiation and can be used for medium throughput screenings (MTS) of compounds or environmental toxics with potential erythro-toxicity and ability to inhibit erythroid differentiation.

Preparation of TiO2 Nanoparticles Using H2O2/TiOSO4 and Applications in Eosin Yellow Photocatalytic Degradation

TiO2 was synthesized in this work by chemical route, when the titanium oxysulfato (TiOSO4) react with 4:6 H2O2/H2O after is dissolved in deionized water. The yellow precipitate was drying at 100oC before heat treated at 400°C to obtain crystalline TiO2. The sample were characterized using FT-IR and X-ray diffraction spectroscopy which identified that product was mixture between two form anatase and rutile. The photocatalytic activity of synthesized TiO2 was tested in the degradation of Eousin yellow which compare with two form of TiO2. Evaluated the results was shown that H2O2 was succeed to preparing TiO2 from TiOSO4 with higher activity then anatase and rutile forms.