Corrosion behavior of high-level waste container materials Ti and Ti–Pd alloy under long-term gamma irradiation in Beishan groundwater

Titanium and titanium–palladium alloys are important potential materials for nuclear waste container, which will endure both intense γ-irradiation and groundwater erosion. Therefore, it is very important to investigate the corrosion behavior of the container materials. In this research, the cumulative dose effect of TA8-1 type titanium–palladium alloy(TA8-1) and TA2-type pure titanium(TA2) under γ-irradiation was studied based on the geological disposal of nuclear wastes. The irradiation experiments were performed at room temperature using60 Co gamma sources with a 5.0-k Gy·h-1 intensity for 40, 80 or 160 days, respectively. The p H value and conductivity of Beishan groundwater were investigated.The results showed that the p H value changed from alkaline(8.22) to acidic(2.46 for TA8-1 and 2.44 for TA2), while the un-irradiated solution remained alkaline(8.17 for TA8-1 and 8.20 for TA2) after 160 days. With the increase of irradiation dose, the conductivity increases rapidly and then tends to become stable, which indicates that the titanium dioxide corrosion layer formed on the surface of the sample surface effectively prevents further corrosion. Meanwhile, XRD and SEM–EDS analysis results show that the main components of corrosion products are Ti O_2 and Ti O. The titanium on the surface of the sample is oxidized, resulting in slight uneven local corrosion. The results show that TA8-1 and TA2 are suitable to be used as candidate materials for high-level waste(HLW) disposal containers due to their excellent performance under long-term and high-dose irradiation corrosion.     

聚γ-缩水甘油醚氧丙基三甲氧基硅烷的合成与表征

采用双金属氰化络合物催化剂(DMC)催化γ-缩水甘油醚氧丙基三甲氧基硅烷(KH560)开环聚合,合成出结构规整的均聚产物PKH560.通过FTIR2、9Si-NMR1、H-NMR对聚合物的结构进行表征.结果表明,以DMC为催化剂,可以实现KH560的开环聚合,合成出分子量较大的目标产物PKH560.凝胶渗透色谱与多角度激光联用仪(GPC/MALLS)测得该聚合物PKH560的数均分子量大于1×104,分子量分布介于1.10与1.35之间;分析不同聚合时间PKH560的数均分子量与单体转化率之间的关系可知,聚合物的数均分子量Mn与单体转化率呈线性增长关系,聚合物的分子量分布较窄(Mw/Mn=1.10~1.35),表明该聚合反应具有活性聚合的特征.     

A Pseudorotaxane System Containing γ-Cyclodextrin Formed via Chiral Recognition with an AuI6AgI3CuII3 Molecular Cap

Solvent-mediated crystal-to-crystal transformations of [Au₆Ag₃Cu₃(H₂O)₃(d -pen)₆(tdme)₂]³⁺ (d -[ 1 (H₂O)₃]³⁺; pen²⁻= penicillaminate, tdme=1,1,1-tris(diphenylphosphinomethyl)ethane) to form unique supramolecular species are reported. Soaking crystals of d -[ 1 (H₂O)₃]³⁺ in aqueous Na₂bdc (bdc²⁻=1,4-benzenedicarboxylate) yielded crystals containing d -[ 1 (bdc)(H₂O)₂]⁺ due to the replacement of a terminal aqua ligand in d -[ 1 (H₂O)₃]³⁺ by a monodentate bdc²⁻ ligand. When γ-cyclodextrin (γ-CD) was added to aqueous Na₂bdc, d -[ 1 (H₂O)₃]³⁺ was transformed to d -[ 1 (bdc@γ-CD)(H₂O)₂]⁺, where a γ-CD ring was threaded by a bdc²⁻ molecule to construct a pseudorotaxane structure. While the use of dicarboxylates with an aliphatic carbon chain instead of bdc²⁻ afforded analogous pseudorotaxanes, such pseudorotaxane species were not formed when crystals of [Au₆Ag₃Cu₃(H₂O)₃(l -pen)₆(tdme)₂]³⁺ (l -[ 1 (H₂O)₃]³⁺) enantiomeric to d -[ 1 (H₂O)₃]³⁺ were soaked in aqueous Na₂bdc and γ-CD, affording only crystals containing l -[ 1 (bdc)(H₂O)₂]⁺.     

Ambient γ-Rays-Mediated Noble-Metal Deposition on Defect-Rich Manganese Oxide for Glycerol-Assisted H2 Evolution at Industrial-Level Current Density

Developing novel synthesis technologies is crucial to expanding bifunctional electrocatalysts for energy-saving hydrogen production. Herein, we report an ambient and controllable γ-ray radiation reduction to synthesize a series of noble metal nanoparticles anchored on defect-rich manganese oxides (M@MnO_2-x, M=Ru, Pt, Pd, Ir) for glycerol-assisted H₂ evolution. Benefiting from the strong penetrability of γ-rays, nanoparticles and defect supports are formed simultaneously and bridged by metal-oxygen bonds, guaranteeing structural stability and active site exposure. The special Ru−O−Mn bonds activate the Ru and Mn sites in Ru@MnO_2-x through strong interfacial coordination, driving glycerol electrolysis at low overpotential. Furthermore, only a low cell voltage of 1.68 V is required to achieve 0.5 A cm⁻² in a continuous-flow electrolyzer system along with excellent stability. In situ spectroscopic analysis reveals that the strong interfacial coordination in Ru@MnO_2-x balances the competitive adsorption of glycerol and OH* on the catalyst surface. Theoretical calculations further demonstrate that the defect-rich MnO₂ support promotes the dissociation of H₂O, while the defect-regulated Ru sites promote deprotonation and hydrogen desorption, synergistically enhancing glycerol-assisted hydrogen production.     

Biodegradable polymeric films based on microbial poly(3-hydroxybutyrate). Effect of gamma-radiation on mechanical properties and biodegradability

Two samples of microbial poly(3-hydroxybutyrate) (PHB) having different molecular weight were used for the preparation of films to be exposed to gamma radiation. The effect of radiation on those samples with high molecular weight increased the fragility of the film. Biodegradability increased with time and reached about 95% after 18 days. Weight-loss of both samples (irradiated and non-irradiated) after 23 days were 100%, for those films with molecular weight of 265 kD.     

Optimization of Mn-Mg-Al Mixed Oxides Composition on their Activity towards the Total Oxidation of Aromatic and Oxygenated VOCs

A series of mixed oxides (Mn-Mg-Al) is prepared by coprecipitation via a hydrotalcite route with different manganese ratios. Structural, textural, and redox properties are studied by XRD, N₂-sorption, H₂-TPR, and XPS techniques. Mn_xMg_6-xAl₂-O mixed oxides (with 0≤x≤6) are tested in the total oxidation of ethanol and toluene, two probe molecules representing respectively oxygenated and aromatic VOCs. Catalysts with higher manganese contents have shown the best catalytic performance for the oxidation of both ethanol and toluene. The surface activity of the materials is mainly related to the presence of manganese species in three different oxidation states (+II, +III, and +IV) in the bulk and on the material's surface. Since high Mn-content catalysts showed similar physicochemical properties and catalytic activity, Mn₄Mg₂-O is selected as the optimal composition of these materials. Furthermore, its aging test is compared to that of noble metal-based commercial catalysts (Pd/γ-Al₂O₃).     

Enhanced skin anti-inflammatory and moisturizing action of gold nanoparticles produced utilizing Diospyros kaki fruit extracts

Inflammatory skin diseases (ISD) cause very severe itchy skin and dryness which is now a days an important issue which has to be taken care. Nanotechnology plays a main role in manufacturing cosmetic ingredients at a nanoscale size. Among different nanoparticles, gold (Au) is one of the non-toxic materials synthesized organically or inorganically. For synthesizing nanoparticles (NPs), using inorganic methods may cause some toxicity to cells, but using organic synthesis like plant extract is less toxic and environmentally friendly. Therefore, we synthesized DK-AuNPs using Diospyros kaki fruit extract. UPLC-MS/MS was used to evaluate phytochemicals responsible for converting salt into nanoparticles. The DK-AuNPs were characterized to confirm the formation of NPs. Furthermore, we analyzed the activity of DK-AuNPs on human keratinocytes (HaCaT cells). The DK-AuNPs showed 98.2 % cell survival upto 200 µg/mL against HaCaT cells. Additionally, compared to DK treatment, DK-AuNPs therapy decreased ROS production in TNF-α/IFN-γ (T + I) stimulated HaCaT cells by 68.7 %, whereas DK treatment reduced ROS generation by 27.8 %. Moreover, the skin anti-inflammatory potential and moisturizing effect of DK-AuNPs were analyzed using HaCaT cells. Furthermore, skin inflammatory activity biomarkers were downregulated through the MAPK/NFκB signaling pathway and showed significant inhibition by DK-AuNPs. Also, the skin moisturizing biomarkers such as HAS (1–3) were upregulated and HYAL (1–2) were downregulated by PI3K/AKT/NFκB through HAS2 regulation. Therefore, skin anti-inflammatory and moisturizing activity were enhanced by treatment with DK-AuNPs. In summary, we conclude that the DK-AuNPs could be a new alternative for skin disease.     

Accessing Dihydropyrrolo[3,4-b]indol-1(2H)-ones via Pd-Catalyzed Intramolecular Aminocarbonylative Ring Closure

Present in a number of small molecule derivatives that display a wide range of biological activities, the dihydropyrrolo[3,4-b]indol-(2H)-one (DHPI) core represents an underexplored heterocyclic scaffold. Given the pharmaceutical potential of the DHPI motif, the development of synthetic methodologies that permit their expedient assembly would be highly desirable. Herein, we describe a novel strategy for the construction of the DHPI core from 3-iodo-1H-indolyl substrates, employing an unprecedented Pd-catalyzed intramolecular aminocarbonylative ring closure. The compatibility of our optimized protocol with various functional groups is highlighted through the synthesis of a range of diversely substituted DHPI derivatives in up to 90 % isolated yield.     

Biological activities from andiroba (Carapa guianensis Aublet.) and its biotechnological applications: A systematic review

Carapa guianensis is a tree from Meliaceae family traditionally known as andiroba that has a wide range of biological properties, including therapeutic effects, antioxidant activities, insecticidal and repellent effects that can be used in biotechnological approaches to medicine, agriculture, and cosmetic products. Therefore, we aim to explore the biological activities exhibited by this species and their respective biotechnological applications of interest. For this, a systematic review was carried out following the PRISMA guidelines dated from 1993 to 2022 through the Scopus, Web of Science and Agricultural Research Database (Base de Dados da Pesquisa Agropecuária - BDPA), screened for biological activity/bioactive compounds. A total of 129 studies were included in the PRISMA flow analysis. Biological properties and major bioactive compounds, as well as biotechnological approaches could be identified. The biological activity from C. guianensis could be observed in different vegetative parts through diverse methods of extractions. These activities are mainly due to the unsaturated fatty acids and bioactive compounds, such as the limonoids and a small fraction of phenolic compounds. Gedunin-type limonoids, like gedunin and its derivatives, represent the class of compounds that show the highest bioactivities in different applications.     

Camellia sinensis: Insights on its molecular mechanisms of action towards nutraceutical,anticancer potential and other therapeutic applications

The Camellia sinensis plant provides a wide diversity of black, green, oolong, yellow, brick dark, and white tea. Tea is one of the majorly used beverages across the globe, succeeds only in the water for fitness and pleasure. Generally, green tea has been preferred more as compared to other teas due to its main constituent e.g. polyphenols which contribute to various health benefits. The aim of this updated and comprehensive review is to bring together the latest data on the phytochemistry and pharmacological properties of Camellia sinensis and to highlight the therapeutic prospects of the bioactive compounds in this plant so that the full medicinal potential of Camellia sinensis can be realised. A review of published studies on this topic was performed by searching PubMed/MedLine, Scopus, Google scholar, and Web of Science databases from 1999 to 2022. The results of the analysed studies showed that the main polyphenols of tea are the four prime flavonoids catechins: epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC) along with the beneficial biological properties of tea for a broad heterogeneity of disorders, including anticancer, neuroprotective, antibacterial, antiviral, antifungal, antiobesity, antidiabetes and antiglaucoma activities. Poor absorption and low bioavailability of bioactive compounds from Camellia sinensis are limiting aspects of their therapeutic use. More human clinical studies and approaching the latest nanoformulation techniques in nanoparticles to transport the target phytochemical compounds to increase therapeutic efficacy are needed in the future.