Showing papers on "Iodine published in 2013"

Atmospheric iodine levels influenced by sea surface emissions of inorganic iodine

Abstract: Naturally occurring bromine- and iodine-containing compounds substantially reduce regional, and possibly global, tropospheric ozone levels. Experimental and model results suggest that the reaction of ozone with iodide could account for around 75% of observed iodine oxide levels over the tropical Atlantic Ocean.

High-performance rechargeable lithium-iodine batteries using triiodide/iodide redox couples in an aqueous cathode

Abstract: Aqueous lithium batteries can store more energy because of their high ionic conductivity compared with the all-solid-state or non-aqueous electrolyte based counterparts. Zhao et al. report a large energy storage density by using safe and low-cost triiodide/iodide redox reaction in an aqueous cathode.

Thermochemical evidence for strong iodine chemisorption by ZIF-8

Abstract: For the first time, using aqueous solution calorimetry, we clearly identify the chemisorption of an unusually strong iodine charge-transfer (CT) complex within the cages of a metal–organic framework. Specifically, we studied the sorption of iodine gas in zeolitic imidazolate framework-8 (ZIF-8, Zn(2-methylimidazolate)2). Two iodine-loaded ZIF-8 samples were examined. The first, before thermal treatment, contained 0.17 I2/Zn on the surface and 0.59 I2/Zn inside the cage. The second sample was thermally treated, leaving only cage-confined iodine, 0.59 I2/Zn. The energetics of iodine confinement per I2 (relative to solid I2) in ZIF-8 are ΔHads = −41.47 ± 2.03 kJ/(mol I2) within the cage and ΔHads = −18.06 ± 0.62 kJ/(mol I2) for surface-bound iodine. The cage-confined iodine exhibits a 3-fold increase in binding energy over CT complexes on various organic adsorbents, which show only moderate exothermic heats of binding, from −5 to −15 kJ/(mol I2). The ZIF-8 cage geometry allows each iodine atom to form two CT...

Tomato fruits: a good target for iodine biofortification

Abstract: Iodine is a trace element that is fundamental for human health: its deficiency affects about two billion people worldwide. Fruits and vegetables are usually poor sources of iodine; however plants can accumulate iodine if it is either present or exogenously administered to the soil. The biofortification of crops with iodine has therefore been proposed as a strategy for improving human nutrition. A greenhouse pot experiment was carried out to evaluate the possibility of biofortifying tomato fruits with iodine. Increasing concentrations of iodine supplied as KI or KIO3 were administered to plants as root treatments and the iodine accumulation in fruits was measured. The influences of the soil organic matter content or the nitrate level in the nutritive solution were analyzed. Finally, yield and qualitative properties of the biofortified tomatoes were considered, as well as the possible influence of fruit storage and processing on the iodine content. Results showed that the use of both the iodized salts induced a significant increase in the fruit’s iodine content in doses that did not affect plant growth and development. The final levels ranged from a few mg up to 10 mg iodine kg-1 fruit fresh weight and are more than adequate for a biofortification program, since 150 µg iodine per day is the recommended dietary allowance for adults. In general, the iodine treatments scarcely affected fruit appearance and quality, even with the highest concentrations applied. In contrast, the use of KI in plants fertilized with low doses of nitrate induced moderate phytotoxicity symptoms. Organic matter-rich soils improved the plant’s health and production, with only mild reductions in iodine stored in the fruits. Finally, a short period of storage at room temperature or a 30-minute boiling treatment did not reduce the iodine content in the fruits, if the peel was maintained. All these results suggest that tomato is a particularly suitable crop for iodine biofortification programs.

Rice (Oryza sativa L.) roots have iodate reduction activity in response to iodine.

Abstract: Although iodine is not an essential nutrient for higher plants, their roots take up and transport the element. However, the exact mechanisms involved in iodine uptake and metabolism in higher plants have yet to be elucidated. In this study, we compared two cultivars differing in iodine tolerance (‘Nipponbare’ and ‘Gohyakumangoku’) to increasing levels of I - and IO 3 - in the root solutions of water-cultured rice ( Oryza sativa L.). We found that IO 3 - added to the root solutions was converted to I - in the presence of roots. Iodate reduction occurred over the course of several hours. Furthermore, the iodate reduction activity of ‘Nipponbare’ (iodine-sensitive) and ‘Gohyakumangoku’ (iodine-tolerant) roots increased after adding IO 3 - or I - . The roots of Barley and soybean also showed iodate reduction activity and the activity responded to iodine treatment either with IO 3 - and I - . This study suggests that plant roots biologically reduce iodate to iodide and indicates that the iodate reduction activity of roots responds to external iodine conditions.

Infant neurocognitive development is independent of the use of iodised salt or iodine supplements given during pregnancy

Abstract: The benefits of iodine supplements during pregnancy remain controversial in areas with a mild-to-moderate iodine deficiency. The aim of the present study was to determine the effect of improving iodine intakes, with iodised salt (IS) or iodine supplements, in pregnant Spanish women. A total of 131 pregnant women in their first trimester were randomly assigned to three groups: (1) IS in cooking and at the table, (2) 200 μg potassium iodide (KI)/d or (3) 300 μg KI/d. No differences were found in thyroid-stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) or thyroid volume (TV) between the three groups. Regardless of the group in which women were included, those who had been taking IS for at least 1 year before becoming pregnant had a significantly lower TV in the third trimester (P= 0.01) and a significantly higher urinary iodine in the first (173.7 (sd 81.8) v. 113.8 (sd 79.6) μg/l, P= 0.001) and third trimesters (206.3 (sd 91.2) v. 160.4 (sd 87.7) μg/l, P= 0.03). Also, no differences were seen in TSH, FT4 or FT3. Children's neurological development was not significantly associated with the consumption of IS for at least 1 year before becoming pregnant and no differences were found according to the treatment group. In conclusion, in pregnant women with insufficient iodine intake, the intake of IS before becoming pregnant was associated with a better maternal thyroid function. The form of iodide intake was not associated with maternal thyroid function or children's neurological development.

Iodine biofortification of vegetable plants——An innovative method for iodine supplementation

Abstract: To elevate the iodine level in edible plants has been shown to be an excellent approach to correct iodine deficiency. We have proposed an innovative approach to produce iodine supplementation by growing vegetables on soils with algal-based iodized organic fertilizer. Ten species of vegetables were tested. The biological absorption and migration of the iodine within the vegetable plants were revealed using microscopy with silver iodide precipitation technique. The results show that the absorption of iodine by the vegetable increases with increasing amount of the algal-based iodized organic fertilizer in general. And the uptake of iodine by leaf vegetable is significantly greater than that by fruit vegetable. Distribution of iodine in various plant organs shows a trend of decreasing iodine concentration from root, leaf, stalk, to fruit. A similar of decreasing concentration can also be found in various cells (cytoplasm>cytoderm>organelles). The exploration of the iodine uptake and biogeochemistry migration mechanisms provides an important scientific foundation for establishing a new method of producing a natural iodine supplementation by iodine biofortification of vegetables.

Conversion of Iodide to Hypoiodous Acid and Iodine in Aqueous Microdroplets Exposed to Ozone

Abstract: Halides are incorporated into aerosol sea spray, where they start the catalytic destruction of ozone (O3) over the oceans and affect the global troposphere. Two intriguing environmental problems undergoing continuous research are (1) to understand how reactive gas phase molecular halogens are directly produced from inorganic halides exposed to O3 and (2) to constrain the environmental factors that control this interfacial process. This paper presents a laboratory study of the reaction of O3 at variable iodide (I–) concentration (0.010–100 μM) for solutions aerosolized at 25 °C, which reveal remarkable differences in the reaction intermediates and products expected in sea spray for low tropospheric [O3]. The ultrafast oxidation of I– by O3 at the air–water interface of microdroplets is evidenced by the appearance of hypoiodous acid (HIO), iodite (IO2–), iodate (IO3–), triiodide (I3–), and molecular iodine (I2). Mass spectrometry measurements reveal an enhancement (up to 28%) in the dissolution of gaseous O...

Uptake Mechanism for Iodine Species to Black Carbon

Abstract: Natural organic matter (NOM) plays an important role in determining the fate and transport of iodine species such as iodide (I–) and iodate (IO3–) in groundwater system. Although NOM exists as diverse forms in environments, prior iodine studies have mainly focused on uptake processes of iodide and iodate to humic materials. This study was conducted to determine the iodide and iodate uptake potential for a particulate NOM (i.e., black carbon [BC]). A laboratory-produced BC and commercial humic acid were used for batch experiments to compare their iodine uptake properties. The BC exhibited >100 times greater uptake capability for iodide than iodate at low pH of ∼3, while iodide uptake was negligible for the humic acid. The uptake properties of both solids strongly depend on the initial iodine aqueous concentrations. After uptake reaction of iodide to the BC, X-ray absorption fine structure spectroscopy results indicated that the iodide was converted to electrophilic species, and iodine was covalently bound ...

In vivo speciation studies and antioxidant properties of bromine in Laminaria digitata reinforce the significance of iodine accumulation for kelps

Abstract: The metabolism of bromine in marine brown algae remains poorly understood. This contrasts with the recent finding that the accumulation of iodide in the brown alga Laminaria serves the provision of an inorganic antioxidant - the first case documented from a living system. The aim of this study was to use an interdisciplinary array of techniques to study the chemical speciation, transformation, and function of bromine in Laminaria and to investigate the link between bromine and iodine metabolism, in particular in the antioxidant context. First, bromine and iodine levels in different Laminaria tissues were compared by inductively coupled plasma MS. Using in vivo X-ray absorption spectroscopy, it was found that, similarly to iodine, bromine is predominantly present in this alga in the form of bromide, albeit at lower concentrations, and that it shows similar behaviour upon oxidative stress. However, from a thermodynamic and kinetic standpoint, supported by in vitro and reconstituted in vivo assays, bromide is less suitable than iodide as an antioxidant against most reactive oxygen species except superoxide, possibly explaining why kelps prefer to accumulate iodide. This constitutes the first-ever study exploring the potential antioxidant function of bromide in a living system and other potential physiological roles. Given the tissue-specific differences observed in the content and speciation of bromine, it is concluded that the bromide uptake mechanism is different from the vanadium iodoperoxidase-mediated uptake of iodide in L. digitata and that its function is likely to be complementary to the iodide antioxidant system for detoxifying superoxide.

Laccase-Catalyzed Oxidation of Iodide and Formation of Organically Bound Iodine in Soils

Abstract: Laccase oxidizes iodide to molecular iodine or hypoiodous acid, both of which are easily incorporated into natural soil organic matter. In this study, iodide sorption and laccase activity in 2 type...

Iodine fortification of vegetables improves human iodine nutrition: in vivo evidence for a new model of iodine prophylaxis.

Abstract: Background: Iodine deficiency is the result of insufficient intake of dietary iodine and as a consequence causes multiple adverse effects. About 2 billion individuals in the world are affected by iodine deficiency. It has been found that the most effective way to control iodine deficiency is through the universal salt iodization. However, salt iodization alone may not be sufficient to assure adequate iodine nutrition. In most industrialized countries, excess consumption of salt has become recognized as a health risk. Therefore, biofortification of vegetables with iodine offers an excellent opportunity to increase iodine intake. Aim and Methods: The aim of this study was to test the efficiency of a new model of iodine prophylaxis in a group of 50 healthy volunteers through the intake of vegetables (potatoes, cherry tomatoes, carrots, and green salad) fortified with iodine. Each serving of vegetables consisted of 100 g of potatoes, carrots, tomatoes, or salad containing 45 mg of iodine (30% of the Recommend...

Intravascular Enhancement With Identical Iodine Delivery Rate Using Different Iodine Contrast Media in a Circulation Phantom

Abstract: PurposeBoth iodine delivery rate (IDR) and iodine concentration are decisive factors for vascular enhancement in computed tomographic angiography. It is unclear, however, whether the use of high–iodine concentration contrast media is beneficial to lower iodine concentrations when IDR is kept identic

Iodine status in preschool children and evaluation of major dietary iodine sources: a German experience

Abstract: Even mild iodine deficiency may negatively affect cognitive performance, especially at a young age. Our aim was to investigate iodine status in very young children and to assess the importance of iodized salt in processed foods of which the use has decreased during the last years in Germany. Twenty-four hours urinary iodine excretion (UIE) as a marker of iodine intake was measured in 378 24 h urine samples collected 2003–2010 by 221 3 to 80 % of iodine supply. Between 2003 and 2010, UIE decreased significantly by approximately 1 μg/d per year. The contribution of salt intake to UIE decreased from 2003–2006 to 2007–2010. In countries where salt is a major iodine source, already modest decreases in the iodized proportion of salt used in processed foods may relevantly impair iodine status even in preschool children.

Hydrogeochemistry of high iodine groundwater: a case study at the Datong Basin, northern China

Abstract: High iodine concentrations in groundwater have seldom been reported and there have been few systematic studies on high iodine groundwater worldwide. To better understand the sources and processes responsible for iodine enrichment in the groundwater of the Datong Basin, the hydrochemical characteristics of groundwater and geochemical features of aquifer sediments were studied. High iodine groundwater mainly occurs in the center of the Datong Basin with iodine concentrations ranging between 3.31 and 1890 μg L−1. Most samples with iodine concentrations higher than 500 μg L−1 are from wells with depths between 75 and 120 m. High pH and a reducing environment are favorable for iodine enrichment in the groundwater, with iodide as the dominant species that accounts for 63.2–99.3% of the total iodine. Sediment samples from a borehole specifically drilled for this study contain 0.18–1.46 mg kg−1 iodine that is moderately correlated with total organic carbon (TOC). The results of sequential extraction experiments show that iodine is mostly bound to iron oxyhydroxides and organic matter in the sediments. The mobilization processes of iodine are proposed to include reductive dissolution of iron oxyhydroxides and transformations among iodide, iodate and organic iodine driven by microbial activities under alkaline and reducing conditions.

Urinary iodine excretion after contrast computed tomography scan: implications for radioactive iodine use.

Abstract: Importance Patients who undergo radiographic studies with contrast receive an enormous bolus of iodine. This can delay subsequent use of radioactive iodine (RAI) therapy because the iodine can compete for uptake. There is a paucity of literature on the minimum interval between contrast administration and RAI therapy. Objective To better characterize how long it takes for the iodine load from an intravenous contrast bolus to clear from the body. Design, Setting, and Participants A prospective cohort of 21 adults undergoing intravenous contrast CT studies at a tertiary academic medical center; exclusion criteria included history of thyroid disease or thyroidectomy, history of renal insufficiency, pregnancy, and other contrast administration within 1 year. Intervention Morning urine samples were taken before the scan for analysis and then every 2 weeks thereafter for 12 weeks. Results The median baseline iodine level was 135 μg/L (range, 29-1680 μg/L), and median peak level was 552 μg/L (range, 62-6172 μg/L). Median time for urinary iodine level to normalize was 43 days, with 75% of subjects returning to baseline within 60 days, and 90% of subjects within 75 days. Baseline iodine level was a significant predictor of postcontrast iodine levels. Age, sex, weight, and estimated glomerular filtration rate were not significant. Conclusions and Relevance These results may be used for guidance on the timing of RAI use following contrast exposure. The practice at our institution is to wait 2 months and then check a 24-hour urinary iodine level. This alleviates concerns about contrast use in patients with thyroid carcinoma interfering with adjuvant radioiodine therapy.

Long-Term Exposure to Excessive Iodine from Water Is Associated with Thyroid Dysfunction in Children

Abstract: Previous studies have indicated an association between iodine excess and increased incidence of thyroid dysfunction in adults. However, there have been few studies on how the intake of excessive iodine affects thyroid function in children. The objective of this study was to assess the effects of a long-term exposure to excessive iodine on thyroid dysfunction in children. Urinary iodine concentration (UIC) and thyroid function in 371 children from a high iodine (HI) area (water iodine: 150-963 μg/L) and 150 children from an adequate iodine (AI) area (water iodine: 12.8-50.9 μg/L) were measured. The water iodine concentration in the HI area was higher than that in the AI area (P < 0.001) and the median urinary iodine concentration of children in the HI area was 1030 μg/L, which was 8.6 times that of children in the AI area (123 μg/L) (P < 0.001). Children in the HI area had a higher concentration of sensitive thyroid stimulating hormone and higher positivity of both thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TGAb). The prevalence of thyroid diseases was higher in HI area children than that in AI area children (P = 0.000), especially subclinical hypothyroidism (SCH; P = 0.004). A body mass index (BMI) of ≥ 22.3 kg/m(2) was associated with the incidence of SCH (OR: 5.51; 95% CI: 1.52, 19.9; P = 0.009). UIC ≥ 600 μg/L (OR: 3.62; 95% CI: 1.22, 10.8; P = 0.024) and TPOAb or TGAb-positivity (Ab+ OR: 6.48; 95% CI: 1.78, 23.6; P = 0.005) in children were significantly and independently associated with SCH. Interactions between UIC ≥ 800 μg/L and Ab+ (P-interaction = 0.004) were found. Furthermore, increased thyroid volume was correlated with higher UIC (β = 0.22; P = 0.002). Excessive iodine intake in children in HI areas is associated with impaired thyroid function; UIC ≥ 600 μg/L and Ab+ are the risk factors for SCH. Effective measures need to be taken for reducing excessive iodine intake.

Selective copper(II) acetate and potassium iodide catalyzed oxidation of aminals to dihydroquinazoline and quinazolinone alkaloids.

Abstract: Copper(II) acetate/acetic acid/O2 and potassium iodide/tert-butylhydroperoxide systems are shown to affect the selective oxidation of ring-fused aminals to dihydroquinazolines and quinazolinones, respectively. These methods enable the facile preparation of a number of quinazoline alkaloid natural products and their analogues.

Iodide-catalyzed halocyclization/cycloaddition/elimination cascade reaction.

Abstract: An iodocyclization reaction of o-alkynylphenyl carboxaldehydes is reported that is truly catalytic with respect to the electrophilic iodine source. With a combination of tetrabutylammonium iodide (TBAI), Oxone as non-nucleophilic and easy to handle co-oxidant, and fluorinated protic solvents, highly substituted 1-naphthalenones could be prepared in high yields of up to 91%.

Potassium iodide (KI) to block the thyroid from exposure to I-131: current questions and answers to be discussed.

Abstract: Thyroid cancer in children and adolescents has to be considered as the most severe health consequence of a nuclear reactor emergency with release of radioiodine into the atmosphere. High doses of potassium iodide are effective to block radioiodine thyroid uptake and to prevent development of thyroid cancer years later. However, there are controversies concerning thyroid cancer risk induced by radioiodine exposure in adults. Further, the interaction of nutritional supply of potassium iodide and radioiodine uptake as well as the interaction of radioiodine with certain drugs has not been addressed properly in existing guidelines and recommendations. How to proceed in case of repeated release of radioiodine is an open, very important question which came up again recently during the Fukushima accident. Lastly, the side effects of iodine thyroid blocking and alternatives of this procedure have not been addressed systematically up to now in guidelines and recommendations. These questions can be answered as follows: in adults, the risk to develop thyroid cancer is negligible. In countries, where nutritional iodine deficiency is still an issue, the risk to develop thyroid cancer after a nuclear reactor emergency has to be considered higher because the thyroid takes up more radioiodine as in the replete condition. Similarly, in patients suffering from thyrotoxicosis, hypothyroidism or endemic goitre not being adequately treated radioiodine uptake is higher than in healthy people. In case of repeated or continued radioiodine release, more than one dose of potassium iodide may be necessary and be taken up to 1 week. Repeated iodine thyroid blocking obviously is not harmful. Side effects of iodine thyroid blocking should not be overestimated; there is little evidence for adverse effects in adults. Newborns and babies, however, may be more sensitive to side effects. In the rare case of iodine hypersensitivity, potassium perchlorate may be applied as an alternative to iodine for thyroid blocking.

Thyroglobulin in smoking mothers and their newborns at delivery suggests autoregulation of placental iodide transport overcoming thiocyanate inhibition

Abstract: Background: Placental transport of iodide is required for fetal thyroid hormone production. The sodium iodide symporter (NIS) mediates active iodide transport into the thyroid and the lactating mammary gland and is also present in placenta. NIS is competitively inhibited by thiocyanate from maternal smoking, but compensatory autoregulation of iodide transport differs between organs. The extent of autoregulation of placental iodide transport remains to be clarified. Objective: To compare the impact of maternal smoking on thyroglobulin (Tg) levels in maternal serum at delivery and in cord serum as markers of maternal and fetal iodine deficiency. Methods: One hundred and forty healthy, pregnant women admitted for delivery and their newborns were studied before the iodine fortification of salt in Denmark. Cotinine in urine and serum classified mothers as smokers (nZ50) or nonsmokers (nZ90). The pregnant women reported on intake of iodine-containing supplements during pregnancy and Tg in maternal serum at delivery and in cord serum were analyzed. Results: In a context of mild-to-moderate iodine deficiency, smoking mothers had significantly higher serum Tg than nonsmoking mothers (mean Tg smokers 40.2 vs nonsmokers 24.4 mg/l, PZ0.004) and so had their respective newborns (cord Tg 80.2 vs 52.4 mg/l, PZ0.006), but the ratio between Tg in cord serum and maternal serum was not significantly different in smokers compared with nonsmokers (smoking 2.06 vs nonsmoking 2.22, PZ0.69). Conclusion: Maternal smoking increased the degree of iodine deficiency in parallel in the mother and the fetus, as reflected by increased Tg levels. However, placental iodide transport seemed unaffected despite high thiocyanate levels, suggesting that thiocyanate-insensitive iodide transporters alternative to NIS are active or that NIS in the placenta is autoregulated to keep iodide transport unaltered.