Iodine Method Research Articles

Study on the decomposition of CuI films due to defect state instability

Cuprous(Ⅰ) iodide (CuI) is widely used as a conducting material in various optoelectronic devices. However, defect properties and instabilities lead to changes in the semiconductor properties of CuI, which seriously affects the stability of related optoelectronic devices. Therefore, in this paper, the decomposition and defect state properties of CuI films are investigated in depth. CuI was prepared by a simple iodination method and belongs to the zinc blende type structure, preferentially crystallizing along the (111) direction. Microscopic tests reveal that grains in CuI film are tightly bonded without obvious cracks or holes, and the grain size reaches 1.231 μm. In the subsequent spectral analysis, multiple emission peaks (free exciton and defect emission peak) were obtained by Gaussian fitting. The two major point defects (Cu vacancy (VCu) and I vacancy (VI)) in CuI were analyzed theoretically, and the calculated defect energy levels matched the energies of the emission peaks. The results of Gaussian waveform fitting and density functional calculations indicate the presence of VCu defects and VI defects in CuI. Significant variations in emission and electrical properties were observed in successive tests, indicating the relatively poor long-term stability of the CuI samples. The changes in the emission characteristics are mainly manifested by the weakening of the 416 nm emission and the enhancement of the 720 nm emission, while the changes in the electrical characteristics are mainly manifested by the increasing resistance. The above changes are attributed to the concentration of defect states, mainly due to the increase of VI defects and the decrease of VCu defects, hence the severe iodine decomposition occurs in the CuI samples. To inhibit the decomposition, three schemes (multiple iodination, multilayer iodination, and encapsulation) were proposed, and relevant experiments were conducted.

Electrochemically Generated Iodine Cations from a Glassy Carbon Electrode for Highly Selective Iodination of Anisole

The synthesis of aryl iodides from commercially available raw chemicals by simple, cheap and green strategies is of fundamental significance. Aryl iodides can undergo a series of homo-/cross-coupling reactions for the synthesis of important industrial chemicals and materials. Traditional methods require the electrophilic substitution on aromatic compounds by iodine or hypervalent iodine compounds, which suffers from the use of erosive halogens or hazardous oxidants. With the development of green chemistry in the field of electrochemical synthesis, anodic oxidation-derived I+ cations have been used for substitution reactions. However, the selectivity of the iodination by these electrochemical methods remains unsatisfactory. We believed that the anolyte is contaminated by trace platinum species from the working electrode. Herein, we report the generation of active I+ species from the anodic oxidation of I2 in acetonitrile using a glassy carbon electrode. With the presence of H+, electrolyte prepared with a glassy carbon anode can react with anisole to selectively form 4-iodoanisole with a yield as high as 97%. On contrast, the electrolytes prepared from Pt and graphite anodes finished the reaction with yields of 16% and 60% for 4-iodoanisole, respectively. This electrochemical method also applies to the iodination of toluene, benzonitrile and bromobenzene, delivering the target para-iodination products with 92%, 84%, and 73% yields, respectively. Thus, an atom-efficient and highly selective aryl iodination method was developed without the use of excessive oxidants.

Optimization of B. cereus PW4 alpha amylase production by OVAT technique

Amylase enzymes are used in a variety of industries. Palm wine was screened for amylase producing microorganisms by starch iodine method. Isolate PW4 was discovered to be the most effective isolate and was identified as Bacillus cereus PW4 (OK384566) by sequencing the 16S rRNA gene. The one-variable-at-a-time strategy was used to optimize α-amylase production parameters, including pH, temperature, incubation duration, inoculum volume, nitrogen source, and metal ion as factors. The enzyme activity was increased to 141.91 U/ml (5.8-fold) in the optimized medium (pH 7, 35 °C, 72 h, 3 % inoculums, 1 % NH4NO3 and 1 % FeCl3) from 24.0 U/ml in the un-optimized medium. Data of the optimal condition will aid in the scaling up of amylase production and other industrial activities.

Comparison of Methods for Estimating Discretionary Salt Intake in Field Settings

ObjectivesAccurate and precise estimates of discretionary salt (DS) intake are critical for designing salt fortification interventions and counseling on salt intake reduction. This study compared four methods of estimating DS intake among non-pregnant women of reproductive age (NPWRA) in northern India to inform the design of a trial of multiply-fortified salt. MethodsParticipants were NPWRA (18–49 y) in Punjab, India. Weighed food records (WFR), same-day duplicate diet (DD) composites, and samples of household (HH) salt were collected simultaneously from 100 women and repeated on a subset of 40. Sodium (Na) and iodine contents of the DD composites were analyzed using Inductively Coupled Plasma (ICP)-Optical Emission Spectrometry and ICP-Mass Spectrometry. HH salt samples were also analyzed for iodine. Methods for estimating DS intake included: 1) WFR: DS consumed from recipes or added at time of consumption were weighed; 2) HH salt disappearance (HHSD): total DS used by HH on the observation day divided by number of HH members; 3) Sodium estimation (NaE): Na content of 40 replicate DD composites prepared without DS were subtracted from the Na content of the corresponding original DD and difference multiplied by the molar mass of NaCl; 4) Iodine method (IM): analyzed iodine content of milk and milk products and commercial snacks were subtracted from DD iodine content, and difference divided by the iodine content of the HH’s salt sample. The relations between methods were explored using Pearson correlation and Bland Altman analyses. ResultsMean ± SD intake of DS according to the WFR, HHSD, and NaE methods were 4.7 ± 1.8 g/d, 5.8 ± 3.3 g/d, and 4.1 ± 2.1 g/d, respectively. Results of IM are pending. Pearson correlation coefficients for DS intake estimates obtained from WFR vs. NaE and WFR vs. HHSD were 0.82 (p < 0.001) and 0.48 (p < 0.001), respectively. Mean ± SD bias (limits of agreement) were 0.68 ± 1.25 g/d (–1.77, 3.13) for WFR vs. NaE, and 1.8 ± 2.93 g/d (–4.56, 6.92) for HHSD vs. WFR methods. ConclusionsDiscretionary salt intake from WFR and NaE showed good agreement and are feasible to implement in field settings. Funding SourcesBill & Melinda Gates Foundation.

Iodine determination in mineral water using ICP-MS: Method development and analysis of brands available in Israeli stores

Reliable iodine determination in drinking water samples has gained importance in the last few decades, mostly due to intensive use of both desalinized water that lacks several important nutritional elements, and bottled mineral water. ICP-MS is a sensitive method for iodine determination that must be performed under alkaline conditions because of the volatile nature of some iodine species. However, in water samples with high pH (>10), slow precipitation of calcium (Ca) and/or magnesium (Mg) carbonates leads to clogging of the ICP-MS nebulizer. We propose preventing this precipitation by adding the chelating agent ethylenediaminetetraacetic acid (EDTA) at 0.1% to a 2% ammonium hydroxide matrix. This concentration of EDTA sufficed for most drinking water samples studied, as long as a 1:1 molar ratio of EDTA to Ca+Mg concentration in the water was maintained. The limit of quantitation of the developed method for iodine was < 0.1 µg L−1. The average iodine concentration in various brands of bottled mineral water sold in Israel was relatively low (average value of seven brands ± standard deviation was 7.67 ± 6.38 µg I L−1). . Regular consumption of either desalinated water or bottled mineral water probably does not supply enough iodine to eliminate iodine deficiency in Israeli consumers. Therefore, continuous follow-up of the iodine status in both tap and bottled water is strongly recommended.

Comparative Study on Elution of Polyvinylpyrrolidone on Dialyzers Using Ultraviolet Analysis and Iodine Method.

It is known that poly(arylethersulfone)-based dialyzers can elute poly( N -vinyl-2-pyrrolidone) (PVP). With regard to chronic renal replacement therapy, this is a burden for the patient, because PVP is deposited in different organs and cannot be degraded or released from there; so elutable PVP has to be minimized. Usually, the iodine method is used for quantification of extractable PVP. To overcome the chain length dependency of this method, we used an ultraviolet method that is independent from the PVP chain lengths; so the absolute amount of eluted PVP can be quantified. The current study shows the amount of eluted PVP on differently sterilized low flux dialyzers (1.6 m 2 , similar storage time, n = 12)-PS160 (Allmed, Egypt), F7HPS (Fresenius Medical Care, Germany), F16 (Wego, China), and B-16P (Bain, China). Using the ultraviolet method, the irradiated filters show a sum total of approximately 9 mg more eluted PVP compared with the steam-sterilized ones, whereas the iodine method shows a value about three times lower between different types of sterilization. The boundary conditions during the radiation sterilization could lead to PVP degradation instead of cross-linking. The resulting shorter PVP chains can be more easily rinsed out and can falsely decrease the calculated eluted PVP amount by using the iodine complexation method.

Screening, Isolation and Characterization of Amylase Producing Bacteria and Optimization for Production of Amylase

The use of amylase enzyme has been extensive in different industrial sectors for quite a long time because of its various applications. In this study, soil from cassava processing site was screened for a bacteria with an amylase producing ability using starch iodine method and dinitrosalicyclic method. The biochemical and molecular characterization revealed the organism to be Bacillus circulan (CS2). Optimization of the enzyme production parameters was first carried out using the one factor at a time (OFAT) approach. The result obtained from OFAT study indicates that the following medium composition and culture conditions; medium pH 8, incubation temperature 45°C, incubation time 48 h, inoculum size 5%(w/v) of starch, lactose 1% (w/v), malt extract 1% (w/v), was suitable for the organism. Further optimization was done using Response Surface Methodology (RSM) based on Central Composite Design (CCD). RSM model was found to have a predicted R2and Adjusted R2value of -0.0666 and 0.3980 respectively and can significantly (p &lt; 0.0500) predicted the response variables. Within the model interaction, effect between the model variables medium pH (A) and Lactose (D) were found to be significant. Optimal conditions for Amylase production by Bacillus circulans are Temperature of 35°C pH of 10 Lactose 1(%) and Malt Extract 2(%) which gave an enzyme activity of 15.776U/mL and biomass of 1.648. B.circulans was partially purified using ammonium sulphate and was also seen to be stable at temperature of 800C and a pH of 6.

RADIOIMMUNOASSAY FOR DETECTION OF ANTI-RINDERPEST ANTIBODIES IN CATTLES

Liquid Phase Radioimmunoassay (RIA) was developed to detect and measure anti-rinderpest immunoglobulins in field animals sera, within two hours. Rinderpest virus adapted on Vero cell line culture and antigen purified by treatment with Triton-Gentron 13 Butanol, and, labeled with I isotope, using chloramin T iodination method. &#x0D; Comparative studies for detecting anti-rinderpest immunoglobulin in 80 calves sera samples, using the developed assay in parallel with virus neutralization test (VNT). The study showed 58.75 % agreement between the two methods. However, 71 % of seven months old, non-vaccinated calves showed anti rinderpest antibodies in their sera, also 81 % of 10 months old vaccinated calves were developed antibodies in their blood. &#x0D; These results demonstrate the development of sensitive, specific and rapid quantitative / qualitative radioimmunoassay, necessary for screening the development of immunity against rinderpest in cattle.

Synthesis and Evaluation of Radioiodine-Labeled pH (Low) Insertion Peptide Variant 7-Like Peptide as a Noninvasive Tumor Microenvironment Imaging Agent in a Mouse MDA-MB-231 Triple-Negative Breast Cancer Model.

The pH (low) insertion peptide (pHLIP) family can target the tumor microenvironment (TME). If pHLIP can be labeled with radioiodine, the imaging and treatment of tumors can be considered. However, tyrosine and tryptophan can bind with iodine in the insertion region of pHLIP, and radioiodine labeling may affect the formation of α-helix structures in acidic environments; therefore, it is necessary to adjust the structure of pHLIP. This study aims to develop an 125I-labeled pH (low) insertion peptide variant 7-like peptide (pHLIP (Var7) LP) for imaging the TME in MDA-MB-231 triple-negative breast cancer (TNBC) xenograft tumor models. Based on pHLIP (Var7), a new peptide sequence, pHLIP (Var7) LP, was obtained by the sequence modification method and then characterized. The binding of pHLIP (Var7) LP to MDA-MB-231 cells was analyzed. pHLIP (Var7) LP was labeled with 125I by the iodogen iodination method. Serial biodistribution studies and small-animal single photon emission computed tomography (SPECT)/computed tomography (CT) imaging in subcutaneous MDA-MB-231 TNBC-bearing mice were performed using [125I] I-pHLIP (Var7) LP. A novel peptide, pHLIP (Var7) LP, has the characteristics of an α-helix structure, electronegativity, and amphiphilicity. Circular dichroism (CD) spectroscopy showed that the peptide presented a typical pH-dependent transition from an unstructured conformation to an α-helix structure when the pH was reduced from 8.0 to 4.0. The relative fluorescence intensities of 5-carboxytetramethylrhodamine (5-TAMRA)-pHLIP(var7) LP at pH = 6.0, 6.6, and 7.4 were 100.00 ± 5.98%, 72.10 ± 4.65%, and 13.72 ± 1.41%, respectively. The distribution of [125I] I-pHLIP (Var7) LP in tumors reached the highest level (8.7 ± 1.6% ID/g) at 2h after injection, and the tumor-to-muscle ratios and tumor-to-blood ratios increased with time. Of the measured off-target organs, the stomach, kidney, and bladder showed higher uptake levels. SPECT imaging revealed rapid and sustained tumor uptake of [125I] I-pHLIP (Var7) LP in breast cancer-bearing mice. This study showed that [125I]I-pHLIP (Var7)LP had rapid and sustained tumor uptake in MDA-MB-231 TNBC and provided a new method for TNBC imaging and further treatment.

Highly transparent flexible CuI film for antibacterial applications

In this study, the CuI film was firstly revealed to have significant antibacterial activity. The as-prepared CuI thin films on flexible plastic (polyvinylchloride, PVC) substrates were developed by the liquid iodination method. This method is simple, low-cost and environmentally friendly to fabricate flexible CuI films. A suitable reaction time between the Cu3N precursor and aqueous iodine solution is the key parameter for developing highly transparent CuI films, and an average transmittance in visible spectrum was higher than 85%. In addition, the CuI films have prominent antibacterial effects against Staphylococcus aureus and Escherichia coli. These properties indicate that CuI films are promising for built-in application to top layer displays in public places, such as hotel and department stores, ticket machines and touch screens in smart devices.

A Metal-Free, Photocatalytic Method for Aerobic Alkane Iodination.

Halogenation is an important alkane functionalization strategy, but O2 is widely considered the most desirable terminal oxidant. Here, the aerobic iodination of alkanes, including methane, was performed using catalytic [nBu4N]Cl and light irradiation (390 nm). Up to 10 turnovers of CH3I were obtained from CH4 and air, using a stop-flow microtubing system. Mechanistic studies using cyclohexane as the substrate revealed important details about the iodination reaction. Iodine (I2) serves multiple roles in the catalysis: (1) as the alkyl radical trap, (2) as a precursor for the light absorber, and (3) as a mediator of aerobic oxidation. The alkane activation is attributed to Cl• derived from photofragmentation of the electron donor-acceptor complex of I2 and Cl-. The kinetic profile of cyclohexane iodination showed that aerobic oxidation of I3- to produce I2 in CH3CN is turnover-limiting.

Transparent thermoelectric properties of copper iodide thin films

Copper Iodide (CuI) transparent thin films were synthesized by using the as-deposited Cu thin film dip in the Iodine (I2) solution (1% per 100 cc.) for 15s, 30s, and 60s within the liquid iodination method. The as-deposited Cu thin films on glass slide substrates as used were prepared by a dc magnetron sputtering method from the Cu target. The microstructure, morphology, and thermoelectric properties were studied by using X-ray diffraction (XRD) techniques, scanning electron microscopy (SEM), and the ZEM-3 method, respectively. The optical property of the film samples was determined from measured transmittance using a UV–visible spectrophotometer. The optical bandgap energy is 3.0 eV and the transmittance is around 80–95% for the thin film as dipped 30s. At room temperature, the power factor of Cul thin films were 14.71, 17.49, and 17.48 μW m−1 K−2 for as dipped 15s, 30s, and 60s, respectively.

Ultrasound-Assisted Iodination of Imidazo[1,2-α]pyridines Via C-H Functionalization Mediated by tert-Butyl Hydroperoxide.

A novel metal catalyst-free and environmentally friendly method for the regioselective iodination of imidazo[1,2-α]pyridines at their C3 position is disclosed, which has a wide substrate scope and could be sustainable. This reaction proceeds through ultrasound acceleration in the presence of a green alcohol solvent. Compared with a conventional heating system, the reaction efficiency and the rate are significantly improved and the iodine atom economy is maximized using ultrasound techniques.

A simple and facile iodination method of didechlorotiacumicin B and aromatic compounds

A simple and facile iodination method of didechlorotiacumicin B and aromatic compounds

Prevalence of intestinal parasites among school children of Janakpurdham, Nepal

There is considerable variation in the findings over the years of study in the prevalence of school-aged children in different parts of Nepal. Recent progress in the living standards of the citizen may affect the prevalence of intestinal parasitosis. This study was aimed to determine the prevalence of different species of gastrointestinal parasites among school children of Janakpurdham, Nepal. A prospective study was carried out by collecting 155 stool samples from 10 randomly selected schools of Janakpurdham. The samples were processed by the formal-ether sedimentation method and then examined microscopically by iodine and wet mount methods. Of the 155 students, 17(10.96%) had one or more parasites. Eight species of parasites were identified during this study, was recorded in 5 pupils representing 3.2% of the study population, followed by 3(1.9%), 2(1.3%), 2(1.3%), 2(1.3%), sp. and each recorded 1(0.6%) respectively. Relatively low prevalence of intestinal parasitosis in school children of Janakpur city still requires more aggressive interventional steps and lifestyle changes.

Selective C-H Iodination of (Hetero)arenes.

Iodoarenes are versatile intermediates and common synthetic targets in organic synthesis. Here, we present a strategy for selective C–H iodination of (hetero)arenes with a broad functional group tolerance. We demonstrate the utility and differentiation to other iodination methods of supposed sulfonyl hypoiodites for a set of carboarenes and heteroarenes.

Development of a novel formula for estimating the amylose content of starch using japonica milled rice flours based on the iodine absorption curve.

The apparent amylose content (AAC) is usually measured by an iodine colorimetric method using the starch as a sample. Nevertheless, it is time-consuming and labor-intensive to prepare rice starch. Therefore, we compared two methods, starch method and milled rice flour method. The former AACs were higher than the latter and correlated with pasting properties, physical properties and sensory scores better than the latter. Therefore, we developed a novel formula for estimating the AACs of starches from japonica rice cultivars using milled rice flours instead of using rice starch. The correlation coefficients of the new formula were 0.89 for calibration and 0.94 for validation, which showed that this equation can be applied to unknown japonica rice samples, and will lead to easy, rapid, and accurate iodine method to determine rice AACs using milled rice flours instead of starch. Abbreviations: AAC: apparent amylose content; RS: resistant starch; SLC: super-long chain; CD: chain length distribution; RVA: Rapid Visco Analyzer; SB: setback; BD: breakdown; Max.vis: maximum viscosity; Min.vis: minimum viscosity; Pt: pasting temperature; Cons: consistency; Final.vis: Final viscosity; SB/Cons: setback/consistency; Max/Min: maximum viscosity/minimum viscosity; Max/Fin: maximum viscosity/final viscosity.

Iodine-131 labeled genistein as a potential radiotracer for breast cancer

ObjectiveGenistein is an isoflavone compound that has been proven to have anticancer activity and is capable of binding to estrogen β receptors with Selective Estrogen Receptor Modulators (SERMs) properties, and has a strong affinity to inhibit the development of cancer cells. This study is to determine the optimum conditions of the reaction in the synthesis process of compounds labeled 131I-genestein which can be potential for application of breast cancer diagnosis. MethodsSynthesis of 131I-Genistein compound labeling using the Chloramine-T iodination method. This method uses several parameter optimizations, including: pH conditions, the amount of chloramine-T oxidizer and sodium metabisulfite reducing agent. The radiochemical purity of the 131I-Genistein compound was determined using thin layer chromatography TLC-SG F254, and measured by SCA (Single Channel Analyzer). The radiochemical purity of labeled compounds must fulfill the requirements of the United States of Pharmacopeia. ResultsOptimization of the synthesis conditions of the 131I-Genistein compound was obtained at pH 8, the amount of chloramine-T 0.225 mg, and the amount of Na-Metabisulfite 0.342 mg, with 30 min reaction time. This optimum condition produces radiochemical purity of 95.02 ± 0.76%. ConclusionProducts labeled 131I-Genistein meet radiochemical purity requirements according to USP requirements. The labeled compound is expected to be able to be used to detect breast cancer through a binding mechanism with estrogen receptors β.

Analisis Variasi Temperatur Aktivasi Terhadap Daya Serap Arang Aktif Tandan Aren (Arenga Pinnata Merr) Dengan Agen Aktivasi Potassium Silicate(K2SiO3)

This study aims to determine the effect of variation of activation temperature of activated carbon from sugar palm bunches of chemically activatied with the activation agent of potassium silicate (K2SiO3) on the adsorption capacity of iodine and methylene blue. Activated carbon from bunches of sugar palmacquired in four steps: preparationsteps, carbonizationstepsusing the pyrolysis reactor with temperature of 300 oC - 400 oC for 8 hours and chemical activation using of potassium silicate (K2SiO3) activator in weight ratio of 2: 1 and physical activation using the electric furnace for 30 minutes with temperature variation of600 oC, 650 oC, 700 oC, 750 oC and 800 oC. The iodine and methyleneblue adsorption testedby Titrimetric method and Spectrophotometry methodrespectively. The results of the adsorption of iodine and methylene blue activated carbon from sugar palm bunches increased from 240.55 mg/g and 63.14 mg/g at a temperature of 600 oC to achieve the highest adsorption capacity of 325.80 mg/g and 73.59 mg/g at temperature of 700 oC and decreased by 257.54 mg/g and 52.03 mg/g at a temperature of 800 oCrespectively.However, it does not meet to Indonesia standard (Standard Nasional Indonesia/SNI), which is 750 mg/g and 120 mg/g respectively.

Transition-Metal-Free Site-Selective γ-C(sp2)-H Monoiodination of Arenes Directed by an Aliphatic Keto Group.

A general γ-C(sp2)-H iodination method directed by an aliphatic keto group has been developed under transition-metal-free conditions for the first time, generating iodoarenes in good to excellent yields with excellent site selectivity. This protocol features a wide range of aryl-substituted ketones, short reaction times, mild reaction conditions, and scalable synthetic procedures. A possible reaction mechanism was also proposed based on several control experiments.