Highly efficient removal of methyl iodide gas by recyclable Cu0-based mesoporous silica.

Developing recyclable adsorbents for co-capture of I2 and CH3I gas is a meaningful and challenging topic. Herein, Cu0-based mesoporous silica (C-S) materials were synthesized and applied for CH3I capture for the first time. Factors (Cu0 content, temperature, contact time and CH3I concentration) affecting the adsorption behavior were investigated. The results demonstrated that the CH3I adsorption capacity of the obtained C-S materials reached up to 1060 mg/g at 200 â„ƒ. Furthermore, the C-S material exhibited excellent reusability (91.3 %, 5 cycles). It was found that Cu0 could cleave the carbon iodine bonds, causing CH3I to dissociate into •CH3 and I-. Then the Cu+ converted from Cu0 reacted with I- to achieve the purpose of CH3I capture. The adsorption mechanism of CH3I on the C-S materials could be concluded that Cu0 reacted with CH3I form CuI (Cu + CH3I → CuI + •CH3). This work suggested that the obtained C-S materials could be promising adsorbents for CH3I capture.

Efficient Reductive N-11C-Methylation Using Arylamines or Alkylamines and In Situ-Generated [11C]Formaldehyde From [11C]Methyl Iodide.

Reductive N-11C-methylation using [11C]formaldehyde and amines has been used to prepare N-11C-methylated compounds. However, the yields of the N-11C-methylated compounds are often insufficient. In this study, we developed an efficient method for base-free reductive N-11C-methylation that is applicable to a wide variety of substrates, including arylamines bearing electron-withdrawing and electron-donating substituents. A 2-picoline borane complex, which is a stable and mild reductant, was used. Dimethyl sulfoxide was used as the primary reaction solvent, and glacial acetic acid or aqueous acetic acid was used as a cosolvent. While reductive N-11C-methylation efficiently proceeded under anhydrous conditions in most cases, the addition of water to the reductive N-11C-methylation generally increased the yield of the N-11C-methylated compounds. Substrates with hydroxy, carboxyl, nitrile, nitro, ester, amide, and phenone moieties and amine salts were applicable to the reaction. This proposed method for reductive N-11C-methylation should be applicable to a wide variety of substrates, including thermo-labile and base-sensitive compounds because the reaction was performed under relatively mild conditions (70°C) without the need for a base.

Hydrophobic nanosheet silicalite-1 zeolite for iodine and methyl iodide capture.

Effective capture of radioactive iodine from nuclear fuel reprocessing is of great importance for public safety as well as the secure utility of nuclear energy. In this work, a hydrophobic nanosheet silicalite-1 (NSL-1) zeolite with an adjustable size was developed for efficient iodine (I2) and methyl iodide (CH3I) adsorption. The optimized all-silica zeolite NSL-1 exhibits an excellent I2 uptake capacity of 553 mg/g within 45 min and a CH3I uptake capacity of 262 mg/g within 1 h. Benefiting from the reduced thickness and enhanced porosity, microporous NSL-1 possesses enhanced iodine adsorption capacity and fast adsorption kinetics, which is a considerable high value among inorganic materials. Unexpectedly, the remarkable characters of high hydrophobicity, acid-resistance and anti-oxidation endow it a higher iodine uptake capacity than traditional aluminosilicate zeolites. More importantly, the high uptake selectivity toward I2 possessed by NSL-1 owing to its hydrophobic skeleton under simulated dynamic conditions. The low cost, facile and scalable synthesis of NSL-1 further highlights great prospects for applications in the nuclear industry. This work provides useful insights for designing efficient adsorbents for iodine capture.

Synthesis of [3 H]Org24598 using in-house prepared [3 H]MeI.

The synthesis of tritium-labelled glycine transporter 1 inhibitor Org24598 is reported. Because of the instability of the Org24598 skeleton under hydrogenation conditions, a synthetic approach using an in-house prepared tritium-labelled alkylating agent ([3 H]MeI, SA = 26.2 Ci/mmol) was employed. Alternative methods of labelling are discussed.

Mapping the Porous and Chemical Structure-Function Relationships of Trace CH3I Capture by Metal-Organic Frameworks using Machine Learning.

Large-scale computational screening has become an indispensable tool for functional materials discovery. It, however, remains a challenge to adequately interrogate the large amount of data generated by a screening study. Here, we computationally screened 1087 metal-organic frameworks (MOFs), from the CoRE MOF 2014 database, for capturing trace amounts (300 ppmv) of methyl iodide (CH3I); as a primary representative of organic iodides, CH3129I is one of the most difficult radioactive contaminants to separate. Furthermore, we demonstrate a simple and general approach for mapping and interrogating the high-dimensional structure-function data obtained by high-throughput screening; this involves learning two-dimensional embeddings of the high-dimensional data by applying unsupervised learning to encoded structural and chemical features of MOFs. The resulting various porous and chemical structure-function maps are human-interpretable, revealing not only top-performing MOFs but also complex structure-function correlations that are hidden when inspecting individual MOF features. These maps also alleviate the need of laborious visual inspection of a large number of MOFs by clustering similar MOFs, per the encoding features, into defined regions on the map. We also show that these structure-function maps are amenable to supervised classification of the performances of MOFs for trace CH3I capture. We further show that the machine-learning models trained on the 1087 CoRE MOFs can be used to predict an unseen set of 250 MOFs randomly selected from a different MOF database, achieving high prediction accuracies.

Structure, anti-tumor activity, and potential anti-tumor mechanism of a fungus polysaccharide from Fomes officinalis.

In our ongoing process of discovering bioactive macromolecules, a homogeneous polysaccharide (FOP80-1) was first purified from Fomes officinalis. FOP80-1 with molecular weight of 4560 Da was mainly composed of →3)-d-Galp-(1→, →4)-ß-d-Manp-(1→, →6)-α-d-Glcp-(1→, →3,6)-d-Glcp-(1→, and t--d-Glcp. Besides the structure features, the anti-tumor activity and potential mechanism of FOP80-1 were also investigated. The cellular and zebrafish experiments revealed that FOP80-1 inhibited tumor proliferation, invasion, and metastasis by increasing ROS, arresting cell cycle, inducing apoptosis, and suppressing angiogenesis. Corresponding to the inhibition of angiogenesis, the surface plasmon resonance (SPR) experiments revealed that FOP80-1 had good affinity with VEGF, a crucial protein to regulate angiogenesis. Molecular docking indicated that FOP80-1 could interact with the protein VEGF.

Important effects of relative humidity on the formation processes of iodine oxide particles from CH3I photo-oxidation.

In this work, laboratory chamber experiments of gas-phase methyl iodide photolysis in the presence of ozone at three relative humidity conditions were performed to study the formation and physico-chemical properties of iodine oxide particles. The obtained results revealed significant morphological changes of iodine oxide particles that were observed to depend on relative humidity. The formed iodine oxide particles under dry conditions were supposed to be agglomerates of fine hygroscopic crystals. On the other hand, a humid atmosphere was observed to favor the formation of isomeric, tetragonal and orthorhombic hygroscopic crystals potentially composed of HIO3 likely formed from progressive hydration of iodine oxide clusters. This process leads to a release of molecular iodine, I2, which may indicate a potential role of I2O4 in the particles' evolution processes. The obtained results on the iodine oxides' behavior are important to the nuclear power plant safety industry since many of the organic iodides that may be released during a major nuclear power-plant accident contain radioactive isotopes of iodine that are known to have lethal or toxic impacts on human health.

Pitch-based porous polymer beads for highly efficient iodine capture.

The efficient and safe capture of volatile radioiodine is of great significance in the reprocessing of spent fuel. Herein, the millimeter-scale pitch-based hyper-cross-linked porous polymers@polyethersulfone (PHCP@PES) composite beads were firstly synthesized for the removal of volatile iodine and methyl iodide. PHCP@PES beads exhibit high iodine vapor and methyl iodide uptake capacities of 770.0 mg/g and 186.5 mg/g, respectively. More impressively, the uptake capacities of PHCP@PES (744.5 mg/g for iodine vapor and 180 mg/g for methyl iodide) remained almost unchanged after treatment with 3 mol/L of nitric acid. The rich interconnected pore structure of PHCP@PES promotes the rapid physical capture of iodine and methyl iodide. Intrinsic features such as low-cost preparation, good mechanical properties as well as thermal, acid stability and excellent performance in iodine capture indicate that PHCP@PES can be used as a potential candidate for the removal of radioactive iodine in the exhaust gas stream of post-treatment plants.

KI and TEDA influences towards the retention of radiotoxic CH3I by activated carbons.

Activated carbons (AC) are widely used within the ventilation networks of nuclear facilities to trap volatile iodine species. In this paper, the performances of various commercial activated carbons towards the trapping of γ-labelled methyl iodide were evaluated in semi-pilot scale under different R.H. according to normalized procedures. A combination between the retention performances and the physico-chemical properties as deduced from several techniques was performed to gain insights about the AC influencing parameters on γ-CH3I capture. Different trends were obtained depending on the impregnant nature and the studied conditions. A high sensitivity of KI/AC towards water vapor was outlined. At R.H. = 40%. The enhancement of water uptake by KI/AC as deduced from water adsorption experiments, leads to decrease the available microporosity for CH3I physisorption, inducing therefore the reduction of performances as a function of KI content at these conditions. At R.H. = 90%, the adsorption mechanism was found to be governed by isotopic exchange reaction since 90% of the microporosity was occupied by water molecules. Therefore, a slight increase of DF was obtained in these conditions. This sensitivity was found to be of a lesser extent for TEDA/AC displaying the highest retention performances whatever the studied condition.

Preparation and structural properties of selenium modified heteropolysaccharide from the fruits of Akebia quinata and in vitro and in vivo antitumor activity.

Cancer is a complex disease, and blocking tumor angiogenesis has become one of the most promising approaches in cancer therapy. Here, an exopoly heteropolysaccharide (AQP70-2B) was firstly isolated from Akebia quinata. Monosaccharide composition indicated that the AQP70-2B was composed of rhamnose, glucose, galactose, and arabinose. The backbone of AQP70-2B consisted of →1)-l-Araf, →3)-l-Araf-(1→, →5)-l-Araf-(1→, →3,5)-l-Araf-(1→, →2,5)-l-Araf-(1→, →4)-d-Glcp-(1→, →6)-d-Galp-(1→, and →1)-d-Rhap residues. Based on the close relationship between selenium and anti-tumor activity, AQP70-2B was modified with selenium to obtain selenized polysaccharide Se-AQP70-2B. Then, a series of methods for analysis and characterization, especially scanning electron microscopy coupled with energy dispersive spectrometry (SEM-EDS), indicated that Se-AQP70-2B was successfully synthesized. Furthermore, zebrafish xenografts and anti-angiogenesis experiments indicated that selenization could improve the antitumor activity by inhibiting tumor cell proliferation and migration and blocking angiogenesis.

Structural elucidation and immunomodulatory evaluation of a polysaccharide from Stevia rebaudiana leaves.

Stevia rebaudiana, a sweetener with medicinal functions, has attracted extensive attention due to its application in food and pharmaceutical fields. However, a few studies were performed to explore polysaccharides in this plant. Herein, SRP70-1 was derived from S. rebaudiana. Structural analysis (monosaccharide composition analysis, high-performance liquid chromatography-multi-angle light scattering detection, gas chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy) revealed that SRP70-1 was composed of mannose, glucose, galactose, and arabinose at the molar ratio of 1.35:1.00:3.23:3.47, with an absolute molecular weight of 7698 Da. SRP70-1 was found to contain â†’ 5)-α-l-Araf-(1→, →2,3,5)-α-l-Araf-(1→, →4)-ß-l-Arap-(1→, →4)-ß-d-Galp-(1→, →6)-ß-d-Galp-(1→, →4)-ß-d-Manp-(1→, →6)-ß-d-Manp-(1→, and terminal α-l-Araf, ß-d-Galp, and ß-d-Glcp residues. Cell experiments showed that SRP70-1 could significantly promote phagocytosis and increase the release of nitric oxide and cytokines including IL-1ß, IL-6, and TNF-α. Further zebrafish experiments confirmed the immunological enhancement effects of SRP70-1. This study revealed that SRP70-1 may be useful for the development of functional foods.

Structure-Activity Relationships between the State of Silver on Different Supports and Their I2 and CH3I Adsorption Properties.

In this study, the performances of silver-impregnated adsorbents prepared from different host supports (SBA-15, alumina, ceria, and faujasite Y zeolite) and calcined or not at 500 °C (1 h) were compared for the capture of I2 and CH3I. By keeping the silver content rather similar (about 15-17 wt %) among the sorbents, it was possible to assess the effect of silver dispersion and speciation on the adsorption capacities measured for both adsorbates. In a first part, several characterization techniques (XRD, DRS-UV-Vis, TEM, etc.) were used to probe the state of silver in the calcined and non-calcined materials. It was found that the characteristics of silver species are strongly influenced by the thermal treatment, the presence or absence of exchange sites, and the stability of the supports. Silver agglomeration was enhanced after calcination at 500 °C especially for supports bearing no exchange sites (SBA-15) or no ordered pores (alumina and ceria). Then, the adsorption performances of the studied silver sorbents were discussed in relation with their physicochemical characteristics. After-test characterizations were useful to assess the proportion of silver species that have reacted with CH3I and I2 to yield AgI precipitates. Depending on the adsorbate, different trends were obtained. I2 adsorption/reaction with silver sites was found to be quantitative (I/Ag ≈1), whatever the silver speciation and dispersion on the support. By contrast, a high proportion of cationic silver species was found essential to increase CH3I adsorption (I/Ag about 0.6-0.7 against 0.2-0.3 for Ag agglomerated species).

Ag-exchanged mesoporous chromium terephthalate with sulfonate for removing radioactive methyl iodide at extremely low concentrations in humid environments.

The development of efficient adsorbents to remove radioactive methyl iodide (CH3I) in humid environments is crucial for air purification after pollution by nuclear power plant waste. In this work, we successfully prepared a post-synthetic covalent modified MIL-101 with a sulfonate group followed by the ion-exchange of Ag (I), which is well characterized by diffuse reflectance FT-IR spectroscopy, X-ray photoelectron spectroscopy (XPS) and the hydrophobic index (HI). After modification of the MOFs, we applied functionalized MIL-101 obtained by either one-pot synthesis (MIL-101-SO3Ag) or a post-synthetic modification process (MIL-101-RSO3Ag, R = NH(CH2)3) to remove the CH3I at an extremely low concentration (0.31 ppm) in an environment with very high relative humidity (RH 95%). Enhanced hydrophobicity of the surface-modified MIL-101 was evaluated by examining the HI with the competitive adsorption of water and cyclohexane vapor, with a high surface area maintained, as confirmed by Ar physisorption. Interestingly, the post-synthetically modified MIL-101-RSO3Ag showed exceptional adsorption performance as determined by its decontamination factor (DF = 195,350) at 303 K and RH 95%. This performance was in comparison to Ag (I)-exchanged 13X zeolite and MIL-101-SO3Ag, which include much higher amounts of Ag. Furthermore, MIL-101-RSO3Ag retained ~94-100% of its fresh adsorbent performance during five cycle repetitions.

Structural analysis and biological effects of a neutral polysaccharide from the fruits of Rosa laevigata.

A neutral water-soluble polysaccharide (RLP50-2) was extracted and purified from the fruits of Rosa laevigata. The absolute molecular weight was determined as 1.26 × 104 g/mol. Monosaccharide composition analysis showed that RLP50-2 mainly consisted of glucose, arabinose, and galactose. Structural analysis revealed that RLP50-2 consisted of →5)-α-L-Araf-(1→, →2,5)-α-L-Araf-(1→, →3,5)-α-L-Araf-(1→, →4)-α-D-Glcp-(1→, →6)-α-D-Glcp-(1→, →3,6)-ß-D-Glcp-(1→, →4)-α-D-Galp-(1→, →6)-ß-D-Galp-(1→, →2)-ß-D-Xylp-(1→, terminal α-L-arabinose, and terminal ß-D-mannose. Biological assays showed that RLP50-2 had immunomodulatory activities using cell and zebrafish models. Moreover, RLP50-2 showed significantly antitumor activities by inhibiting tumor cell proliferation and migration and blocking angiogenesis. These results suggested that RLP50-2 could be developed as a potential immunomodulatory agent or antitumor candidate drug in biomedicine field.

Spatial distribution and biogeochemical cycling of methyl iodide in the Yellow Sea and the East China Sea during summer.

Methyl iodide (CH3I) released from ocean is an important carrier of iodine, which plays an important role in ozone depletion in the atmosphere. Depletion of ozone has increased the amount of ultraviolet radiation that reaches the earth's surface and recent global warming has caused oceanic acidification as well as dust events, but how these environmental changes will affect CH3I concentration in the ocean is unclear. In this study, the spatial distributions and sources of CH3I in the atmosphere, seawater, and sediment porewater were measured in the Yellow Sea (YS) and the East China Sea (ECS) between June and July 2018. Higher concentrations in the atmosphere, seawater, and sediment were found in the YS than in the ECS, and surface seawater emissions were discovered to be the major contributors of atmospheric CH3I concentrations. Anthropogenic pollutants could explain significant spatial variation in the distribution of CH3I. High concentrations of CH3I in sediment porewater increased diffusion into bottom waters, with diffusive fluxes of 0.2-6.5 nmol m-2 d-1. Preliminary results during the in situ seawater incubation experiments showed that the photochemical production rate of CH3I ranged from 0.008 to 0.214 pmol L-1 h-1 under ultraviolet light, and an enhancement emission of CH3I from phytoplankton occurred with the addition of dust, while a reduction of CH3I appeared under lower pH conditions.

Structural properties and in vitro and in vivo immunomodulatory activity of an arabinofuranan from the fruits of Akebia quinata.

In our continuous searching for natural active polysaccharides with immunomodulatory activity, an arabinofuranan (AQP70-3) was isolated and purified from the fruits of Akebia quinata (Houtt.) Decne. by using ion-exchange chromatography and gel permeation chromatography for the first time. AQP70-3 contained both α-l-Araf and ß-l-Araf, and the absolute molecular weight was 1.06 × 104 g/mol. The backbone of AQP70-3 comprised →5)-α-l-Araf-(1→, →3,5)-α-l-Araf-(1→, and →2,5)-α-l-Araf-(1→, with branches of →1)-ß-l-Arafand →3)-α-l-Araf-(1→ residues. Biological assay suggested that AQP70-3 can stimulate phagocytic activity and promote the levels of nitric oxide (NO), interleukin (IL)-6, IL-1ß, and tumor necrosis factor-α (TNF-α) of RAW264.7 cells. Furthermore, AQP70-3 was found to increase the production of reactive oxygen species (ROS) and NO in zebrafish embryo model.

Production of Methyl-Iodide in the Environment.

Iodine is an essential micronutrient for most of the living beings, including humans. Besides its indispensable role in animals, it also plays an important role in the environment. It undergoes several chemical and biological transformations resulting in the production of volatile methylated iodides, which play a key role in the iodine's global geochemical cycle. Since it can also mitigate the process of climate change, it is reasonable to study its biogeochemistry. Therefore, the aim of this review is to provide information on its origin, global fluxes and mechanisms of production in the environment.

Immobilization of Radioiodine via an Interzeolite Transformation to Iodosodalite.

We described a technology for immobilizing radioiodine in the sod-cages by the interzeolite transformation of iodine-containing LTA (zeolite A) and FAU (zeolites X and Y) into a sodalite (SOD) structure. The immobilization of iodine in the sod-cage was confirmed using diverse characterization methods including powder XRD, elemental analysis, SEM-EDS, 127I MAS NMR, and I 3d XPS. Although both zeolites A (Na-A) and X (Na-X) were well converted into SOD structure in the presence of NaI and AgI, the iodide anions were fixed in the sod-cages only when NaI was used. The ability to adsorb methyl iodide (CH3I) was evaluated for zeolites A and X in which Na+ and/or Ag+ ions were exchanged, and Ag+ and zeolite X showed better adsorption properties than Na+ and zeolite A, respectively. However, when both CH3I adsorption ability and the successive immobilization of iodine by interzeolite transformation were considered, Na-X was determined to be the best candidate of adsorbent among the studied zeolites. More than 98% of the iodine was successfully immobilized in the sod-cage in the SOD structure by the interconversion of Na-X following CH3I adsorption, although the Na-X zeolite exhibited half the CH3I adsorption capacity of Ag-X.

Mannose-anchored N,N,N-trimethyl chitosan nanoparticles for pulmonary administration of etofylline.

Drug delivery to lungs via pulmonary administration offers potential for the development of new drug delivery systems. Here we fabricated the etofylline (ETO) encapsulated mannose-anchored N,N,N-trimethyl chitosan nanoparticles (Mn-TMC NPs). The prominent characteristics like biocompatibility, controlled release, targeted delivery, high penetrability, enhanced physical stability, and scalability mark Mn-TMC NPs as a viable alternative to various nanoplatform technologies for effective drug delivery. Mannosylation of TMC NPs leads to the evolution of new drug delivery vehicle with gratifying characteristics, and potential benefits in efficient drug therapy. It is widely accepted that following pulmonary administration, the introduction of mannose to the surface of drug nanocarriers provide selective macrophage targeting via receptor-mediated endocytosis. The fabricated Mn-TMC NPs exhibited particle size of 223.3 nm, PDI 0.490, and ζ-potential -19.1 mV, drug-loading capacity 76.26 ± 1.2%, and encapsulation efficiency of 91.75 ± 0.88%. Sustained drug release, biodegradation studies, stability, safety, and aerodynamic behavior revealed the effectiveness of prepared nanoformulation for pulmonary administration. In addition, the in vivo pharmacokinetic studies in Wistar rat model revealed a significant improvement in therapeutic efficacy of ETO, illustrating mannosylation a promising approach for efficient therapy of airway diseases following pulmonary administration.

Isolation, structural elucidation, and immunoregulation properties of an arabinofuranan from the rinds of Garcinia mangostana.

In our search for bioactive polysaccharides as immunomodulatory agents, an arabinofuranan (GMP90-1) was purified and characterized from the rinds of Garcinia mangostana L. GMP90-1 (absolute molecular weight: 5.30 × 103 g/mol) was found to be composed of arabinose, galactose, and rhamnose. The backbone of GMP90-1 was determined as (1→5)-linked α-l-Araf, (1→2,3,5)-linked α-l-Araf, (1→3,5)-linked α-l-Araf, (1→6)-linked ß-d-Galp, and (1→2)-linked α-l-Rhap. Conformational analysis revealed GMP90-1 to exist as a rigid rod structure in sodium chloride solution. To explore its potential as immunomodulatory agents, an in vitro cell screening was performed and GMP90-1 was found to significantly enhance the phagocytic uptake of neutral red and improve the secreted level of nitric oxide (NO), interleukin (IL)-6, IL-1ß, and tumor necrosis factor-α (TNF-α) of macrophages. Furthermore, the cellular immunomodulatory activities were confirmed by the in vivo zebrafish experiment, which suggested that GMP90-1 with immunomodulatory effects could be considered as a potential immunomodulatory for immune diseases.