Low Iodide Research Articles

Mangiferin: An effective agent against human malignancies.

Mangiferin is a bioactive substance present in high concentration in mangoes and also in some other fruits. Owing to its potential as a chemopreventive and chemotherapeutic agent against several types of cancer, this unique, significant, and well-researched polyphenol has received a lot of attention recently. It possesses the ability to treat cancers, including rectal cancer, prostate cancer, ovarian cancer, leukemia, gastric cancer, liver cancer, chronic pancreatitis, and lung cancer. It can control/regulate multiple key signaling pathways, such as signal transducer and activator of transcription 3 (STAT3), second mitochondria-derived activator of caspases/direct inhibitor of apoptosis (IAP)-binding protein with low propidium iodide (pl) (Smac/DIABLO) nuclear factor kappa B (NF-κB), phosphatidylinositol 3 kinase/protein 3 kinase (PI3K/Akt), transforming growth factor beta/suppressor of mothers against decapentaplegic (TGF-β/SMAD), c-jun N-terminal kinase/p38 mitogen-activated protein kinase (JNK/p38-MAPK), and phosphor-I kappa B kinase (p-IκB), which are crucial to the development of cancers. By triggering apoptotic signals and halting the advancement of the cell cycle, it can also prevent some cancer cell types from proliferating and developing. It has been revealed that mangiferin targets a variety of adhesion molecules, cytokines, pro-inflammatory transcription factors, kinases, chemokines, growth factors, and cell-cycle proteins. By means of preventing the onset, advancement, and metastasis of cancer, these targets may mediate the chemopreventive and therapeutic effects of mangiferin. Mangiferin has confirmed potential benefits in lung, cervical, breast, brain, and prostate cancers as well as leukemia whether administered alone or in combination with recognized anticancer compounds. More clinical trials and research investigations are required to completely unleash the potential of mangiferin, which may lower the risk of cancer onset and act as a preventive and therapeutic alternative for a number of cancers.

Regulation of iodine-glucose flip-flop in SW1736 anaplastic thyroid cancer cell line.

The alternative manner of iodide and glucose uptake found in different types of thyroid cancer, referred to flip-flop. ATC cells indicate low iodide uptake and high glucose uptake, which lack the morphology and genetic characteristics of well-differentiated tumors and become increasingly invasive. Importance placed on the discovery of innovative multi-targeted medicines to suppress the dysregulated signaling in cancer. In this research, we aimed to clarify molecular mechanism of Rutin as a phytomedicine on anaplastic thyroid cancer cell line based on iodide and glucose uptake. The MTT test was employed to test cell viability. Iodide uptake assay was performed using a spectrophotometric assay to determine iodide uptake in SW1736 cells based on Sandell-Kolthoff reaction. For glucose uptake detection, ''GOD-PAP'' enzymatic colorimetric assay was applied to measure the direct glucose levels inside of the cells. Determination of NIS, GLUT1 and 3 mRNA expression in SW1736 cells was performed by qRT-PCR. Determination of NIS, GLUT1 and 3 protein levels in SW1736 cells was performed by western blotting. According to our results, Rutin inhibited the viability of SW1736 cells in a time- and dose-dependent manner. Quantitative Real-time RT-PCR analysis exposed that NIS mRNA levels were increased in Rutin treated group compared to the control group. Accordingly, western blot showed high expression of NIS protein and low expression of GLUT 1 and 3 in Rutin treated SW1736 cell line. Rutin increased iodide uptake and decreased glucose uptake in thyroid cancer cell line SW1736 compared to control group. Multiple mechanisms point to Rutin's role as a major stimulator of iodide uptake and inhibitor of glucose uptake, including effects at the mRNA and protein levels for both NIS and GLUTs, respectively. Here in, we described the flip-flop phenomenon as a possible therapeutic target for ATC. Moreover, Rutin is first documented here as a NIS expression inducer capable of restoring cell differentiation in SW1736 cell line. It also be concluded that GLUTs as metabolic targets can be blocked specifically by Rutin for thyroid cancer prevention and treatment.

Impact of (nano ZnO/multi-wall CNTs) prepared by arc discharge method on the removal efficiency of stable iodine 127I and radioactive iodine 131I from water

Radioactive iodine isotopes especially 131I are used for diagnosis and treatment of different types of cancer diseases. Due to the leak of radioactive iodine into the patient’s urine in turn, the wastewater would be contaminated, so it is worth preparing a novel adsorption green material to remove the radioactive iodine from wastewater efficiently. The removal of 127I and 131I contaminants from aqueous solution is a problem of interest. Therefore, this work presents a new study for removing the stable iodine 127I− and radioactive iodine 131I from aqueous solutions by using the novel nano adsorbent (Nano ZnO/MWCNTs) which is synthesized by the arc discharge method. It is an economic method for treating contaminated water from undesired dissolved iodine isotopes. The optimal conditions for maximum removal are (5 mg/100 ml) as optimum dose with shacking (200 rpm) for contact time of (60 min), at (25 °C) in an acidic medium of (pH = 5). After the adsorption process, the solution is filtrated and the residual iodide (127I−) is measured at a maximum UV wavelength absorbance of 225 nm. The maximum adsorption capacity is (15.25 mg/g); therefore the prepared nano adsorbent (Nano ZnO/MWCNTs) is suitable for treating polluted water from low iodide concentrations. The adsorption mechanism of 127I− on to the surface of (Nano ZnO/MWCNTs) is multilayer physical adsorption according to Freundlich isotherm model and obeys the Pseudo-first order kinetic model. According to Temkin isotherm model the adsorption is exothermic. The removal efficiency of Nano ZnO/MWCNTs for stable iodine (127I−) from aqueous solutions has reached 97.23%, 89.75%, and 64.78% in case of initial concentrations; 0.1843 ppm, 0.5014 ppm and 1.0331 ppm, respectively. For the prepared radio iodine (131I−) solution of radioactivity (20 µCi), the dose of nano adsorbent was (10 mg/100 ml) and the contact time was (60 min) at (pH = 5) with shacking (200 rpm) at (25 °C). The filtration process was done by using a syringe filter of a pore size (450 nm) after 2 days to equilibrate. The removal efficiency reached (34.16%) after the first cycle of treatment and the percentage of residual radio iodine was (65.86%). The removal efficiency reached (94.76%) after five cycles of treatment and the percentage of residual radio iodine was (5.24%). This last percentage was less than (42.15%) which produces due to the natural decay during 10 days.

3D visualization of oil-abundant limon flavedo layer under drying

This study investigated the transformations of lemon flavedo tissues during freeze-drying based on high-resolution X-ray micro-computed tomography (μ-CT) and confocal laser scanning microscopy (CLSM). Contrast-enhanced segmentation, traversal statistic algorithmic analysis, and 3D visualization of lemon peel texture are studied. To avoid pseudo-imaging caused by precipitation of contrast enhancer, low concentration cesium iodide was used to improve X-ray contrast and decrease enlarged inter-cellular region. X-ray μ-CT showed the precipitation of contrast enhancers at the intercellular boundary after freeze-drying. The grayscale thresholding method was presented as the most suitable segmentation method for detecting cell walls due to the high noise level caused by low contrast enhancer concentration in the reconstructed images. The faster water loss at the primary drying stage caused the disintegration of oil glands and induced high porosity of 0.7 % in fresh to 0.84 % in 0.5 h freeze-dried. The results suggest that noise filtering based on voxel statistics provides an efficient approach for the inter and intra-cellular microstructural analysis of excessively watery plant tissues with low contrast enhancer concentration.

Enhanced Circular Dichroism and Polarized Emission in an Achiral, Low Band Gap Bismuth Iodide Perovskite Derivative.

Lead halide perovskites and related main-group halogenido metalates offer unique semiconductor properties and diverse applications in photovoltaics, solid-state lighting, and photocatalysis. Recent advances in incorporating chiral organic cations have led to the emergence of chiral metal-halide semiconductors with intriguing properties, such as chiroptical activity and chirality-induced spin selectivity, enabling the generation and detection of circularly polarized light and spin-polarized electrons for applications in spintronics and quantum information. However, understanding the structural origin of chiroptical activity remains challenging due to macroscopic factors and experimental limitations. In this work, we present an achiral perovskite derivative [Cu2(pyz)3(MeCN)2][Bi3I11] (CuBiI; pyz = pyrazine; MeCN = acetonitrile), which exhibits remarkable circular dichroism (CD) attributed to the material's noncentrosymmetric nature. CuBiI features a unique structure as a poly-threaded iodido bismuthate, with [Bi3I11]2- chains threaded through a cationic two-dimensional coordination polymer. The material possesses a low, direct optical band gap of 1.70 eV. Notably, single crystals display both linear and circular optical activity with a large anisotropy factor of up to 0.16. Surprisingly, despite the absence of chiral building blocks, CuBiI exhibits a significant degree of circularly polarized photoluminescence, reaching 4.9%. This value is comparable to the results achieved by incorporating chiral organic molecules into perovskites, typically ranging from 3-10% at zero magnetic field. Our findings provide insights into the macroscopic origin of CD and offer design guidelines for the development of materials with high chiroptical activity.

Comparative analysis of thyroid hormone systems in rodents with subterranean lifestyle

African mole-rats are subterranean rodents inhabiting underground burrows. This habitat entails risks of overheating, hypoxia, and scarce food availability. Consequently, many subterranean species have evolved low basal metabolism and low body temperature, but the regulation of these traits at the molecular level were unknown. Measurements of serum thyroid hormone (TH) concentrations in African mole-rats have revealed a unique TH phenotype, which deviates from the typical mammalian pattern. Since THs are major regulators of metabolic rate and body temperature, we further characterised the TH system of two African mole-rat species, the naked mole-rat (Heterocephalus glaber) and the Ansell’s mole-rat (Fukomys anselli) at the molecular level in a comparative approach involving the house mouse (Mus musculus) as a well-studied laboratory model in TH research. Most intriguingly, both mole-rat species had low iodide levels in the thyroid and naked mole-rats showed signs of thyroid gland hyperplasia. However, contrary to expectations, we found several species-specific differences in the TH systems of both mole-rat species, although ultimately resulting in similar serum TH concentrations. These findings indicate a possible convergent adaptation. Thus, our study adds to our knowledge for understanding adaptations to the subterranean habitat.

Recent progress in the stabilization of low band-gap black-phase iodide perovskite solar cells.

All-inorganic and organic-inorganic hybrid perovskite solar cells (PSCs) have taken a quantum leap owing to their high performance and low-cost solution processability. Their efficiency has been dramatically increased up to ∼26%, matching the conventional inorganic photovoltaics like monocrystalline Si (26.1%), polycrystalline Si (21.6%), CdTe (22.1%), and CIGS (22.3%). Such outstanding performance has been achieved due to their excellent optoelectronic properties, such as a direct bandgap in the visible region, a very high absorption coefficient, a long charge-carrier diffusion length, and ambipolar carrier transport characteristics. FAPbI3 (FA = formamidinium) and CsPbI3 perovskites among the pool of perovskites are recommended for solar cell applications because they meet all the requirements for photovoltaic applications. However, the fundamental problem of these perovskites is that their photoactive black phase is highly unstable under ambient conditions due to small and large sizes of Cs+ and FA+ ions, respectively. The instability of the black phase of these perovskites hinders their applications in photovoltaic devices as a high-quality light absorber layer. Several approaches have been employed to prevent the formation of the photo-inactive yellow phase or to enhance the stability of the black phase of perovskites, such as dimensional and compositional engineering, the addition of external additives, and dimensional engineering. This perspective summarizes the various methods for stabilizing the black phase of CsPbI3 and FAPbI3 perovskites at room temperature as well as their application in photovoltaic devices.

Enhancing the sensitivity towards iodide detection by coupling SECM and an EĆ catalytic mechanism

In this work, a gold conventional sized electrode (r = 3 mm) and a gold microelectrode (r = 12.5 µm) were employed to investigate the EC’ mechanism involving the anodic oxidation of iodide in the presence of the non-redox-active species thiosulfate. A significant anodic current increase, due to the electrocatalytic process, was noticed in cyclic voltammograms recorded in an iodide solution in the presence of thiosulfate when compared to iodide solution only, at the same experimental conditions. Aiming to enhance the sensitivity of the electroanalytical method towards iodide detection, Scanning Electrochemical Microscopy (SECM) was employed to confine reactants and products in a thin-layer cell defined by the solution region between the microelectrode tip and a Au substrate. Very low iodide concentrations, in the range of a 1–10 µmol/L, can be detected at a short tip-substrate distance, and the method was validated by measuring the analyte content in a synthetic urine sample.

Spontaneous Symmetry Breaking: The Case of Crazy Clock and Beyond

In this work, we describe the crazy-clock phenomenon involving the state I (low iodide and iodine concentration) to state II (high iodide and iodine concentration with new iodine phase) transition after a Briggs–Rauscher (BR) oscillatory process. While the BR crazy-clock phenomenon is known, this is the first time that crazy-clock behavior is linked and explained with the symmetry-breaking phenomenon, highlighting the entire process in a novel way. The presented phenomenon has been thoroughly investigated by running more than 60 experiments, and evaluated by using statistical cluster K-means analysis. The mixing rate, as well as the magnetic bar shape and dimensions, have a strong influence on the transition appearance. Although the transition for both mixing and no-mixing conditions are taking place completely randomly, by using statistical cluster analysis we obtain different numbers of clusters (showing the time-domains where the transition is more likely to occur). In the case of stirring, clusters are more compact and separated, revealed new hidden details regarding the chemical dynamics of nonlinear processes. The significance of the presented results is beyond oscillatory reaction kinetics since the described example belongs to the small class of chemical systems that shows intrinsic randomness in their response and it might be considered as a real example of a classical liquid random number generator.

Photocatalyst assemblies with two halide ions

A series of ruthenium polypyridyl photocatalysts bearing amide functional groups were designed that successfully promoted halide assembly in CH2Cl2 and CH3CN solution. In CH2Cl2, halide assembly was accompanied by a visible color change, and the spectral changes presented clear evidence for two halide binding events, yielding a 1:2 ruthenium:halide assembly. In the more polar solvent CH3CN, 1:2 assembly structures were also observed with chloride, bromide, and iodide, and large equilibrium constants were measured for association of the first and second halide (K11 = 0.04 – 2 × 106 M−1, K12 = 0.01 – 3 × 105 M−1). Varying the functional groups on the ancillary ligands tuned the excited-state reduction potentials (Ru2+⁎/+), resulting in a photocatalyst capable of performing iodide oxidation. Quenching of the photocatalyst excited state resulted in static and dynamic quenching, and a Stern-Volmer analysis yielded two linear regions at low and high iodide concentrations. The dynamic quenching rate constants (kq = 6.8 and 4.0 × 1010 M−1 s−1) and static quenching constants (KS = 2.4 and 0.13 × 104 M−1) at low and high iodide concentrations, respectively, were consistent with dynamic quenching of Ru2+ and [Ru2+,I−]+, and static quenching of [Ru2+,I−]+and [Ru2+,2I−]. Transient absorption spectroscopy revealed that the quenching reaction yielded a reduced ruthenium (Ru+) as the primary photoproduct and diiodide (I2•−) as a secondary photoproduct. The second-order rate constant for I2•− formation was measured to be 2.5 × 1010 M−1 s−1, a value consistent with the diffusion limited reaction. The transient absorption data indicates that oxidized halide photoproducts only result from the diffusional quenching reactions, and not from static quenching with an associated iodide ion. Fast back-electron transfer rates and low cage-escape yields in the ruthenium:iodide assemblies are invoked to explain why the static quenching pathway does not lead to measurable photoproduct yields.

Iodine and thyroid status during pregnancy and risk of stillbirth: A population-based nested case-control study.

Prior research suggests that severe iodine deficiency in pregnancy may be associated with stillbirth. However, the relationship between mild to moderate iodine insufficiency, which is prevalent even in developed countries, and risk of stillbirth is unclear. We thus examined associations of iodine status and risk of stillbirth in a prospective population‐based nested case–control study in Finland, a mild to moderately iodine insufficient population. Stillbirth cases (n = 199) and unaffected controls (n = 249) were randomly selected from among all singleton births in Finland from 2012 to 2013. Serum samples were collected between 10 and 14 weeks gestation and analysed for iodide, thyroglobulin (Tg) and thyroid‐stimulating hormone (TSH). Odds ratios (ORs) and 95% confidence intervals (CIs) for stillbirth were estimated using logistic regression. After adjusting for maternal age, prepregnancy body mass index, socio‐economic status and other factors, neither high nor low serum iodide was associated with risk of stillbirth (Q1 vs. Q2–Q3 OR = 0.92, 95% CI = 0.78–1.09; Q4 vs. Q2–Q3 OR = 0.78; 95% CI = 0.45–1.33). Tg and TSH were also not associated with risk of stillbirth in adjusted models. Maternal iodine status was not associated with stillbirth risk in this mildly to moderately iodine‐deficient population. Tg and TSH, which reflect functional iodine status, were also not associated with stillbirth risk. The lack of associations observed between serum iodide, TSH and Tg and risk of stillbirth is reassuring, given that iodine deficiency in pregnancy is prevalent in developed countries.

Treatment of Graves’ Disease With a Combination of Low Iodine Diet and Potassium Iodide Plus Radioactive Iodine Treatment

Introduction: Graves’ disease (GD) is usually treated with radioactive iodine I131 (RAI), thionamide or surgery. Of these, RAI remains the safest and most efficacious treatment. We report 3 patients with GD who were treated with low iodine diet (LID), followed by RAI and subsequent potassium iodide (SSKI) administration.Case series:Patient 1 - A 50-year-old male presented with weight loss, heat intolerance and palpitations. Physical examination: HR 120 bpm, BP 110/80mmHg, no evidence of thyroid orbitopathy. Thyroid: 50 grams diffusely enlarged and brisk DTR. Lab findings: TSH 0.001, FT4 4.2, total T3 410, TSI 172. A thyroid scan revealed diffuse uptake 72% at 4-hours. He was diagnosed with GD and treated with methimazole. Three weeks later a CBC showed an absolute neutrophil count 820. After discontinuing methimazole, he was placed on prednisone 40mg daily and LID. Two weeks later (24-hours urine iodine <50 mcg), he received 15mCi I131. 72 hours later he was administered SSKI one drop BID for 3 days. Four weeks after RAI, TFT was normal. Two months later, he required levothyroxine treatment for hypothyroidism. Patient 2 - A 23-year-old female presented with weight loss and nervousness. Physical examination revealed HR 110 bpm, BP 100/70 mmHg, no thyroid orbitopathy, a diffusely enlarged thyroid. Serum TSH <0.005, FT4 3.9, total T3 398, TSI 149. Thyroid uptake showed 70% at 24-hours. Patient was started on methimazole and atenolol. Four weeks later she developed severe generalized erythematous rash. After treating with prednisone for one week she was placed on LID and treated with 15 mCi I131. Six weeks later TSH was 0.4 with a free T4 of 1.8 and four months later she required levothyroxine therapy for hypothyroidism. Patient 3 - A 40-year-old male presented with atrial fibrillation and hyperthyroidism. Patient received treatment for atrial fibrillation and physical examination confirmed heart rate 78 (on treatment), no evidence of thyroid orbitopathy, and diffusely enlarged thyroid. Serum TSH <0.005, FT4 3.1, total T3 298, TSI 231. Thyroid scan was consistent with GD with a 24-hr uptake of 62%. He refused to take methimazole due to fear of adverse side effects. After placing him on prednisone along with LID for 2weeks, he was treated with I131 15 mCi. 72 hours later he received SSKI one drop BID for 3 days. Prednisone was discontinued 2 weeks later. Six weeks following treatment, TSH was 1.1 with FT4 1.32. Patient remained euthyroid for the next 12 months of follow up. Discussion: LID given before RAI therapy has a potential of depleting total iodine pool which can increase the I131 uptake in the thyroid gland and facilitate β-radiation to the thyroid gland. SSKI following RAI can improve retention of I131 in the thyroid gland and reduce the recycling of radioactivity between the thyroid and the blood. In summary, a LID prior to RAI and SSKI following RAI treatment be beneficial in certain patients with GD.

Adsorption of methyl iodide on reduced silver‐functionalized silica aerogel: Kinetics and modeling

AbstractThe low concentration methyl iodide (CH3I) adsorption process on reduced silver‐functionalized silica aerogel (Ag0‐Aerogel) was studied. The kinetic data were acquired using a continuous flow adsorption system. Because the corresponding physical process was observed, the shrinking core model (SCM) was modified and applied. An average CH3I pore diffusivity was calculated, the CH3I‐Ag0‐Aerogel reaction was identified as a 1.40 order reaction instead of first order reaction, and the nth order reaction rate constant was determined. This modified SCM significantly increases the accuracy of adsorption behavior prediction at low adsorbate concentration. Modeling results indicate that the overall adsorption process is controlled by the pore diffusion. However, at low adsorbate concentration (ppbv level), the CH3I adsorption is limited to the surface reaction due to the low uptake rate in a predictable time period.

Vertical and seasonal variations of dissolved iodine concentration in coastal seawater on the northwestern Pacific coast of central Japan

Vertical and seasonal variations in the concentrations of total dissolved iodine (TDI), iodide (I−), iodate (IO3−), and dissolved organic iodine (DOI) were examined for seawaters from the northwestern Pacific coast of central Japan (48 m water depth, ca. 1 km offshore) from 2012 to 2016. The annual averages of TDI and iodate concentrations in the upper layer (water depth < 10 m) were below those from deeper levels. Additionally, the concentrations decreased significantly during summer to autumn. The vertical and seasonal trends in TDI and iodate concentrations were suggested to be originated from the uptake of iodate by settling particles within the water column and partially from the input of river waters. The annual average of iodide concentration in the upper layer was higher than that in deeper levels, and the concentration tended to increase during summer to autumn. Further, the iodide concentration showed a significant positive correlation with the water temperature. The results suggest that the iodide concentration was mainly controlled by the efficiency of vertical mixing in the water column, as deeper seawater generally contains low iodide concentration. The vertical and seasonal variations in DOI concentration were erratic and thus obscured its controlling factors.

Chloramination of iodide-containing waters: Formation of iodinated disinfection byproducts and toxicity correlation with total organic halides of treated waters

The formation of iodinated disinfection byproducts (I-DBPs) in drinking waters is of a concern due to their higher cyto- and genotoxicity than their chlorinated and brominated analogues. This study investigated the formation of I-DBPs under chloramination conditions using preformed chloramine and associated cyto- and geno-toxicities obtained with Chinese Hamster Ovary (CHO) cell assay. Cyto- and geno-toxicity of the samples were also calculated using DBP toxicity index values and correlated with total organic halide (TOX) formation. In low iodide (I-) (0.32 μM, 40 μg L−1) water, increasing dissolved organic carbon (DOC) concentration of selected waters from 0.1 to 0.25 mg L−1 increased the formation of iodinated trihalomethanes (I-THMs), while further increases from 0.25 to 4 mg L−1 produced an opposite trend. In high iodide water (3.2 μM, 400 μg L−1), increasing DOC from 0.5 to 4 mg L−1 gradually increased the I-THM formation, while a decrease was observed at 5.4 mg L−1 DOC. Iodoform was the most influenced species from the changes in DOC concentration. While increasing the initial iodide concentration from 0 to 5 μM increased the formation of iodoform, it did not make any considerable impact on the formation of other I-THMs. The measured cytotoxicity of samples was significantly correlated with increasing DOC concentration. Unknown TOCl and TOI showed a high correlation with measured cytotoxicity, while calculated total organic chlorine (TOCl) and total organic iodine (TOI) did not correlate. The comparison of measured and calculated cytotoxicity values showed that the calculated values do not always represent the overall cytotoxicity, since the formation of unknown DBPs are not taken into consideration during the toxicity calculations.

An Estimation of Volatile Iodine in a Pool at Low pH and High Iodide Concentrations Under Irradiation

A new empirical model is proposed for estimating the amount of volatile iodine in an aqueous phase. The volatile iodine concentration is estimated for highly irradiated CsI solutions in which the pH of the solution changes. The reaction of CsI solution with water radiolysis products is not balanced because radiolysis products are continuously produced under irradiation. Thus the kinetic of the chemical equation is important to determine iodine behavior in a CsI solution. An empirical model for the kinetic equation including the oxidation and reduction reaction is proposed. The proposed model was validated with a wide range of experimental data. A comparison of the experiments and predictions by the model indicated that the predicted volatile iodine from CsI solution with a concentration of 10−3 to 10−4 M was in good agreement. For 10−5 M CsI solution, the predicted iodine concentration was much smaller than experimental data due to the fact that I− was rapidly converted to IO3−.

Strain and layer modulated electronic and optical properties of low dimensional perovskite methylammonium lead iodide: Implications to solar cells

In the present work we report the effect of quantum confinement, biaxial and uniaxial strains on electronic properties of two dimensional (2D), one dimensional (1D) and layered system of Methylammonium lead iodide (MAPI) in cubic phase using first principles calculations based on density functional theory for its implications to solar cell. Our studies show that the bandgap of MAPI is dimension dependent and is maximum for 1D. We also found that the band gap of 2D MAPI can be modulated through application of biaxial strain, which shows linear relation with strain; compressive strain decreases the band gap whereas tensile strain increases the band gap. 1D MAPI shows near parabolic response towards strain which increases with compressive and tensile strain. Our studies show that the 2D MAPI is better for a solar cell due to lower effective mass of electron and hole arising from the strong s-p anti-bonding coupling. The calculated solar cell parameters suggest that the 2D MAPI is best suited for solar cell applications. The calculated open circuit voltage, fill factor and efficiency are highest for 2D MAPI. The highest theoretical efficiency of 2D MAPI is 23.6% with mesoporous (mp)-TiO2 electrode.

Influence of physicochemical properties of various soil types on iodide and iodate sorption

Studies that deal with iodine mobility in uncontaminated agricultural soils are scarce and unique. Therefore, in this article, we have evaluated the sorption behavior of two most abundant naturally occurring inorganic iodine species – iodide and iodate – in several soil types. Our results showed that the sorption process is extremely slow with equilibrium achieved after ten days. The sorption of both iodine species is well described by Freundlich isotherm. The affinity of iodine for all investigated soils in the observed concentration range is relatively low. Our results showed that besides iodine speciation, sorption efficiency is highly dependent on soil types and their characteristics. While in mineral soils with low organic carbon content iodide sorption is dominant, organic rich soils are more favorable for iodate sorption. Organic carbon, clay content, pH and the abundance of iron, aluminum and manganese oxides and hydroxides showed to be the most important soil properties controlling iodine sorption. Our results provide new insight into the complex iodine behavior and retention in soils. This is crucial for better understanding of iodine mobility and the ability to enter the food chain.

Role of fungal laccase in iodide oxidation in soils

Previously, we hypothesized that microbial laccase oxidizes iodide (I−) in soils to molecular iodine (I2) or hypoiodous acid (HIO), both of which are easily incorporated into natural soil organic matter, and thus plays a role in iodine sorption on soils. In this study, soil iodide oxidase activity was determined by a colorimetric assay to evaluate if laccase is responsible for iodide oxidation in soils. Three types of Japanese soil showed significant iodide oxidase activities (0.751–2.87 mU g soil−1) at pH 4.0, which decreased with increasing pH, until it was no longer detected at pH 5.5. The activity was inhibited strongly by autoclaving or by the addition of common laccase inhibitors. Similar tendency of inhibition was observed in soil laccase activity, which was determined with 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) as a substrate. Significant positive correlations (R2 values of 0.855–0.896) between iodide oxidase activity and laccase activity were observed in two of three soils. Commercially available fungal laccases showed only very low iodide oxidase activities (4.68–18.0 mU mg−1), but enhanced activities of 102–739 mU mg−1 were observed in the presence of redox mediators. Finally, we successfully isolated fungal strains with iodide-oxidizing phenotype in the presence of redox mediators. Polyacrylamide gel electrophoresis of the culture supernatant of Scytalidium sp. strain UMS and subsequent active stain revealed that the fungal laccase actually oxidized iodide in the presence of redox mediators. These results suggest that at least part of iodide in soils is oxidized by fungal laccase through the laccase-mediator system.

Amperometric and potentiometric determination of iodide using carbon electrodes modified with salophen complex

A statistical treatment was carried out on electrochemical methods intended for iodide determination as a tracer in seawater reservoirs. Comparison was made for amperometric and potentiometric detection, including the use of a modified carbon electrode. The potentiometric method showed a good linear correlation coefficient (r=0.9926) with a Nernstian behavior in a concentration range of 10−5 to 1molL−1 (1.3mgL−1 to 127gL−1) and a limit of detection of 1.3mgL−1 (10μmolL−1). The amperometric method showed a good linear correlation coefficient (r=0.9988) with a linear response over a concentration range of 1 to 4mgL−1 (8 to 31.5μmolL−1) and a limit of detection of 0.5mgL−1 (4μmolL−1). The statistic treatment has shown that the potentiometric method is promising to measure the iodide concentration in samples with high iodide content and the amperometric method is appropriate to measure the iodide concentration in samples with low iodide content, for example, in the case of produced water from petroleum reservoirs. Moreover, the salophen modified electrode can be readily used for routine analysis in laboratory.