Y2O3 Nanoparticles and X-ray Radiation-Induced Effects in Melanoma Cells

The innovative strategy of using nanoparticles in radiotherapy has become an exciting topic due to the possibility of simultaneously improving local efficiency of radiation in tumors and real-time monitoring of the delivered doses. Yttrium oxide (Y₂O₃) nanoparticles (NPs) are used in material science to prepare phosphors for various applications including X-ray induced photodynamic therapy and in situ nano-dosimetry, but few available reports only addressed the effect induced in cells by combined exposure to different doses of superficial X-ray radiation and nanoparticles. Herein, we analyzed changes induced in melanoma cells by exposure to different doses of X-ray radiation and various concentrations of Y₂O₃ NPs. By evaluation of cell mitochondrial activity and production of intracellular reactive oxygen species (ROS), we estimated that 2, 4, and 6 Gy X-ray radiation doses are visibly altering the cells by inducing ROS production with increasing the dose while at 6 Gy the mitochondrial activity is also affected. Separately, high-concentrated solutions of 25, 50, and 100 µg/mL Y₂O₃ NPs were also found to affect the cells by inducing ROS production with the increase of concentration. Additionally, the colony-forming units assay evidenced a rather synergic effect of NPs and radiation. By adding the NPs to cells before irradiation, a decrease of the number of proliferating cell colonies was observed with increase of X-ray dose. DNA damage was evidenced by quantifying the γ-H2AX foci for cells treated with Y₂O₃ NPs and exposed to superficial X-ray radiation. Proteomic profile confirmed that a combined effect of 50 µg/mL Y₂O₃ NPs and 6 Gy X-ray dose induced mitochondria alterations and DNA changes in melanoma cells.     

TPR investigations on the reducibility of Cu supported on Al2O3, zeolite Y and SAPO-5

Reducibility of Cu supported on Al₂O₃, zeolite Y and silicoaluminophosphate SAPO-5 has been investigated in dependence on the Cu content using a method combining conventional temperature programmed reduction (TPR) by hydrogen with reoxidation in N₂O followed by a second the so-called surface-TPR (s-TPR). The method enables discrimination and a quantitative estimation of the Cu oxidation states +2, +1 and 0. The quantitative results show that the initial oxidation state of Cu after calcination in air at 400 °C, independent on the nature of the support, is predominantly +2. Cu²⁺ supported on Al₂O₃ is quantitatively reduced by hydrogen to metallic Cu⁰. Comparing the TPR of the samples calcined in air and that of samples additionally pre-treated in argon reveals that in zeolite Y and SAPO-5 Cu²⁺ cations are stabilized as weakly and strongly forms. In both systems, strongly stabilized Cu²⁺ ions are not auto-reduced by pre-treatment in argon at 650 °C, but are reduced in hydrogen to form Cu⁺. The weakly stabilized Cu²⁺ ions, in contrast, may be auto-reduced by pre-treatment in argon at 650 °C forming Cu⁺ but are reduced in hydrogen to metallic Cu⁰.     

Phase equilibria in the P2O5-rich part of the system Y2O3−Na2O−P2O5

In the ternary system Y₂O₃?Na₂O?P₂O₅, the partial system Y(PO₃)₃?NaPO₃?P₂O₅ was examined by means of differential thermal analysis and X-ray powder diffraction; its phase diagram is given.     

Modelling and mutation studies on the histamine H1-receptor agonist binding site reveal different binding modes for H1-agonists: Asp116 (TM3) has a constitutive role in receptor stimulation

Summary A modelling study has been carried out, investigating the binding of histamine (Hist), 2-methylhistamine (2-MeHist) and 2-phenylhistamine (2-PhHist) at two postulated agonistic binding sites on transmembrane domain 5 (TM5) of the histamine H₁-receptor. For this purpose a conformational analysis study was performed on three particular residues of TM5, i.e., Lys²⁰⁰, Thr²⁰³ and Asn²⁰⁷, for which a functional role in binding has been proposed. The most favourable results were obtained for the interaction between Hist and the Lys²⁰⁰/Asn²⁰⁷ pair. Therefore, Lys²⁰⁰ was subsequently mutated and converted to an alanine, resulting in a 50-fold decrease of H₁-receptor stimulation by histamine. Altogether, the data suggest that the Lys²⁰⁰/Asn²⁰⁷ pair is important for activation of the H₁-receptor by histamine. In contrast, analogues of 2-PhHist seem to belong to a distinct subclass of histamine agonists and an alternative mode of binding is proposed in which the 2-phenyl ring binds to the same receptor location as one of the aromatic rings of classical histamine H₁-antagonists. Subsequently, the binding modes of the agonists Hist, 2-MeHist and 2-PhHist and the H₁-antagonist cyproheptadine were evaluated in three different seven--helical models of the H₁-receptor built in homology with bacteriorhodopsin, but using three different alignments. Our findings suggest that the position of the carboxylate group of Asp¹¹⁶ (TM3) within the receptor pocket depends on whether an agonist or an antagonist binds to the protein; a conformational change of this aspartate residue upon agonist binding is expected to play an essential role in receptor stimulation.Abbreviations 2-MeHist 2-methylhistamine - 2-PEA 2-pyridyl-ethylamine - 2-PhHist 2-phenylhistamine - CHO Chinese hamster ovary - E_int interaction energy - E_str strain energy - GES global energy structure - gpH₁R guinea pig H₁-receptor - GPCR G-protein coupled receptor - Hist histamine - N proximal nitrogen - N tele nitrogen - TM transmembrane domain - WT wild type     

SiO2 Fibers of Two Lengths and Their Effect on Cellular Responses of Macrophage-like Cells

The immunoreactivity or/and stress response can be induced by nanomaterials’ different properties, such as size, shape, etc. These effects are, however, not yet fully understood. This study aimed to clarify the effects of SiO₂ nanofibers (SiO₂NFs) on the cellular responses of THP-1-derived macrophage-like cells. The effects of SiO₂NFs with different lengths on reactive oxygen species (ROS) and pro-inflammatory cytokines TNF-α and IL-1β in THP-1 cells were evaluated. From the two tested lengths, it was only the L-SiO₂NFs with a length ≈ 44 ± 22 µm that could induce ROS. Compared to this, only S-SiO₂NFs with a length ≈ 14 ± 17 µm could enhance TNF-α and IL-1β expression. Our results suggested that L-SiO₂NFs disassembled by THP-1 cells produced ROS and that the inflammatory reaction was induced by the uptake of S-SiO₂NFs by THP-1 cells. The F-actin staining results indicated that SiO₂NFs induced cell motility and phagocytosis. There was no difference in cytotoxicity between L- and S-SiO₂NFs. However, our results suggested that the lengths of SiO₂NFs induced different cellular responses.     

Effect of thermal and acid treatment on the structure of NH4Na—Y zeolite by IR data

The structural transformations of ammonium-exchanged forms of Na-Y zeolite during thermal evacuation and acid treatment were studied using IR spectroscopy. The formation of the zeolite H-forms by shallow-bed evacuation of NH₄N-Y at 570 K is accompanied by a high-frequency shift of the bands in the IR lattice vibration spectra. In the formation of the H⁺-forms resulting from the decationization of zeolite by treatment with an aqueous HCl solution, no shifts of the bands are observed. During deep-bed calcination in air the H⁺-form, is transformed into the H-form completed by the formation of a highly-crystalline stabilized zeolite at 623 K. A rapid increase in the shallow-bed calcination temperature results in a collapse of the structure of the H- and H⁺-forms followed by the formation of amorphous SiO₂.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 236–240, February, 1995.     

Effects of temperature and pressure on the near-infrared spectra of HOD in D2O

The near-infrared absorption spectra (9500 to 11000 cm^–1) of HOD, 20 mol% in D₂O were measured at temperatures between 4 and 55°C and pressures up to 500 MPa. From the analysis of the spectra, the following conclusions are drawn. (1) At temperatures below about 38°C, the ice I-like bulky structure is destroyed to form the dense structure which reflects the high-pressure ice-like structure as the pressure is increased. (2) At temperatures above about 38°C, the bulky structure hardly remains at atmospheric pressure and the formation of dense structure proceeds monotonically with increasing pressure. The results and conclusion obtained in the present paper agrees with those obtained for pure H₂O water in the previous investigation.     

Gastroprotective Effects of Inulae Flos on HCl/Ethanol-Induced Gastric Ulcers in Rats

Inulae Flos, the flower of Inula britannica L., is used as a dietary supplement, beverage, and medicine in East Asia. In this study, we evaluated the gastroprotective effects of Inulae Flos extract (IFE) against gastric mucosal lesions induced by hydrochloric acid (HCl)/ethanol in rats and explored its potential mechanisms by measuring antioxidant enzyme activity, mucus secretion, and prostaglandin E₂ (PGE₂) levels. Pretreatment with IFE at doses of 100 and 300 mg/kg significantly inhibited gastric lesions in HCl/ethanol-treated rats. IFE increased the activities of superoxide dismutase and catalase and the levels of glutathione and PGE₂ in gastric tissues. The administration of IFE also significantly increased the gastric wall mucus contents in HCl/ethanol-induced gastric lesions. These findings suggest that IFE has gastroprotective effects against HCl/ethanol-induced gastric lesions and exerts these effects through increased antioxidant levels and gastric mucus secretion. Inulae Flos may be a promising agent for the prevention and treatment of gastritis and gastric ulcers.     

焙烧温度对In2TiO5纳米带晶型结构及光催化性能的影响

以Ti(OC₄H₉)₄、In(NO₃)₃和聚乙烯吡咯烷酮(PVP-K30)为原料,采用静电纺丝技术制备了In₂TiO₅纳米带。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)和N₂吸附-脱附等技术对不同焙烧温度处理得到的样品进行表征,详细研究了焙烧温度对In₂TiO₅纳米带晶粒尺寸、形貌、比表面积和孔径的影响。以20 mg·L^-1的氟喹诺酮类抗生素左氧氟沙星(LEV)为目标降解物,125 W高压汞灯为光源,评价了不同焙烧温度下In₂TiO₅纳米带的光催化活性。结果表明,焙烧温度对In₂TiO₅的形貌与光催化活性有明显影响。当焙烧温度为800℃时,制备的In₂TiO₅纳米带表面光滑,其宽度为(552±58) nm、厚度约为140 nm,光催化活性最强,光照60 min,LEV的降解率可以达到95%。     

焙烧温度对In2TiO5纳米带晶型结构及光催化性能的影响

以Ti(OC₄H₉)₄、In(NO₃)₃和聚乙烯吡咯烷酮(PVP-K30)为原料,采用静电纺丝技术制备了In₂TiO₅纳米带。利用X射线衍射(XRD)、扫描电子显微镜(SEM)、紫外-可见漫反射光谱(UV-Vis DRS)和N₂吸附-脱附等技术对不同焙烧温度处理得到的样品进行表征,详细研究了焙烧温度对In₂TiO₅纳米带晶粒尺寸、形貌、比表面积和孔径的影响。以20 mg·L^-1的氟喹诺酮类抗生素左氧氟沙星(LEV)为目标降解物,125 W高压汞灯为光源,评价了不同焙烧温度下In₂TiO₅纳米带的光催化活性。结果表明,焙烧温度对In₂TiO₅的形貌与光催化活性有明显影响。当焙烧温度为800℃时,制备的In₂TiO₅纳米带表面光滑,其宽度为(552±58) nm、厚度约为140 nm,光催化活性最强,光照60 min,LEV的降解率可以达到95%。     

Capacitance and photocurrent study of electronic properties of anodic oxide films on Nb and Ta. Evaluation of the ionized donor concentration profile in Nb2O5 film

Electronic properties of electrochemically formed oxide films on Nb were studied by photocurrent and differential capacitance measurements in 0.025 M KH₂PO₄+0.025 M Na₂HPO₄ electrolyte, pH 6.9. Oxide films of n-type conductivity were formed galvanostatically for final potentials ranging from 4 to 230 V. Measurements were performed in two potential regions, which correspond to formation of a depleted layer of variable thickness at relatively low potentials, and to complete depletion of oxide films of electronic charge carriers at higher potentials. In the first potential region the behavior of both capacitance and photocurrent, was governed by a build up of a depleted layer of potential dependent thickness. In the second, high potential, region, which extends up to the oxide film formation potential, the photocurrent and capacitance of oxide films in most features followed the trends typical of dielectric films containing defects and traps. The photocurrent and capacitance measurements on presumably dielectric oxide films formed on Ta were staged for comparison. The capacitance–potential measurements performed in the first potential region enabled us to construct the ionized donor concentration profile across the Nb₂O₅ film width. The limitations on the use of the C–E profiling method for electrochemically formed oxide layers are considered.     

Different behaviors of HZSM-5 zeolites synthesized in different procedures in loading of MoCl5 and methanol to gasoline (MTG) reaction

MoCl₅ was loaded on the HZSM-5 samples synthesized with or without organic template. Besides differences in their surface migration and catalytic properties in MTG reaction, the Al species in the former is found to be more stable than that of the latter.     

Repurposing the Antiplatelet Agent Ticlopidine to Counteract the Acute Phase of ER Stress Condition: An Opportunity for Fighting Coronavirus Infections and Cancer

Different pathological conditions, including viral infections and cancer, can have a massive impact on the endoplasmic reticulum (ER), causing severe damage to the cell and exacerbating the disease. In particular, coronavirus infections, including SARS coronavirus-2 (SARS-CoV-2), responsible for COVID-19, cause ER stress as a consequence of the enormous amounts of viral glycoproteins synthesized, the perturbation of ER homeostasis and the modification of ER membranes. Therefore, ER has a central role in the viral life cycle, thus representing one of the Achilles’ heels on which to focus therapeutic intervention. On the other hand, prolonged ER stress has been demonstrated to promote many pro-tumoral attributes in cancer cells, having a key role in tumor growth, metastasis and response to therapies. In this report, adopting a repurposing approach of approved drugs, we identified the antiplatelet agent ticlopidine as an interferent of the unfolded protein response (UPR) via sigma receptors (SRs) modulation. The promising results obtained suggest the potential use of ticlopidine to counteract ER stress induced by viral infections, such as COVID-19, and cancer.     

Er~(3+)∶V_(0.01)Y_(2.99)Al_5N_(0.01)F_(0.01)O_(11.98)/BiPO_4/Pt光催化剂的制备及其在降解废水中亚甲基蓝的应用

通过溶胶-凝胶法合成了上转换发光材料Er~(3+)∶V_(0.01)Y_(2.99)Al_5N_(0.01)F_(0.01)O_(11.98)(Er∶YAG),然后利用水热法合成了BiPO_4,再利用高温煅烧法合成了Er∶YAG/BiPO_4/Pt复合物光催化剂.通过使用X-射线粉末衍射仪(XRD),扫描电子显微镜(SEM),透射电子显微镜(TEM),光致发光光谱(PL)和上转换发射光谱对样品的组成、形貌及光学特征进行了表征.此外,还研究了不同甘油添加量、 Er∶YAG和BiPO_4的摩尔比例和复合温度及光催化剂的循环使用次数对Er∶YAG/BiPO_4/Pt复合物光催化剂活性的影响.实验结果显示Er∶YAG/BiPO_4/Pt复合物光催化剂具有高的光催化活性和较好的稳定性,它可以作为一种高效的光催化剂用于污水中有机污染物的处理.     

Simultaneous capillary electrophoretic determination of Sc(III) and Y(III) based on the complex-formation with a lacunary Keggin-type [PW11O39] complex

Trace amounts of Sc(III) and Y(III) can react with [PW₁₁O₃₉]⁷⁻ to form the ternary Keggin-type complexes: [P(Sc^IIIW₁₁)O₄₀]⁶⁻ and [P(Y^IIIW₁₁)O₄₀]⁶⁻ having high molar absorptivities in the UV region. Since the rate of the complex-formation was very rapid and the kinetically stable ternary anions migrated in the capillary with different electrophoretic mobilities, the complex-formation reaction was applied to the simultaneous CE determination of Sc(III) and Y(III) with direct UV detection at 250 nm. For both Sc(III) and Y(III), the pre-column method provided linear calibration curves in the range of 2 × 10⁻⁷ to 1 × 10⁻⁵ M; the respective detection limits were 1 × 10⁻⁷ M (the signal-to-noise ratio = 3). The proposed method was successfully applied to the determination of Sc(III) and Y(III) in river water.     

Synthesis, structure and magnetic properties of the S=1/2, one-dimensional antiferromagnet, Y5Re2O12

Single crystals of Y₅Re₂O₁₂ have been grown, and the crystal structure has been determined by X-ray diffraction. This compound crystallizes in space group C2/m with cell dimensions of a=12.4081(10) Å b=5.6604(5)Å, c=7.4951(6) Å, β=107.837(3)°, Z=2. The final refinement led to R1=0.0238, WR2=0.0459 for 1053 observed reflections with F>4σ(F₀). Edge-sharing ReO₆ octahedra form infinite linear [ReO₂O_4/2]_n chains along the b direction with alternating short and long Re-Re distances. Three crystallographically independent yttrium atoms surround O2 to form OY₄ tetrahedra, which share edges and corners in the ab plane to form a two-dimensional Y₅O₄ network which separates the [ReO₂O_4/2]_n magnetic chains. This compound is therefore isostructural with the series Ln₅Re₂O₁₂Ln=Gd-Lu, which have been known since 1969. The average Re oxidation state is +4.5 in the chains and a reasonable, if qualitative MO scheme results in one unpaired electron per Re dimer. Consistent with this, magnetic susceptibility data can be fitted to the one-dimensional antiferromagnetic Heisenberg model with S=1/2 and parameters J^intra/k=−89(1)K, g=2.15(4) and χ(TIP)=5(1)×10⁻⁴ emu/mol. There is no sign of long-range magnetic order down to 2 K. These results are contrasted with those for the isostructural Y₅Mo₂O₁₂.     

Nitric acid in the presence of supported P2O5 on silica gel: an efficient and novel reagent for oxidation of sulfides to the corresponding sulfoxides

This paper describes an efficient and easy method for oxidation of sulfides 1 to their corresponding sulfoxides 2 with nitric acid in the presence of supported P₂O₅ on silica gel under solvent-free conditions in high yields.     

总气压与Ar/O2流量比对直流对向靶磁控溅射TiO2薄膜光催化性能的影响

采用对向靶磁控溅射法在不同气压和Ar/O₂流量比条件下, 以氟化SnO₂ (FTO)导电玻璃为基底制备了多晶TiO₂薄膜. 台阶仪测量结果显示所制备TiO₂薄膜的平均厚度约为200 nm. 随着溅射气压的升高, TiO₂薄膜由锐钛矿与金红石混晶结构转变为纯锐钛矿结构. 分别采用场发射扫描电镜(FESEM)和原子力显微镜(AFM)分析了不同气压和Ar/O₂流量比对TiO₂薄膜表面形貌的影响, 结果显示TiO₂薄膜的表面粗糙度随溅射总气压和Ar/O₂流量比的增加而增大. 以初始浓度为100×10^-6 (体积分数)的异丙醇(IPA)气体为目标物检测所制备TiO₂薄膜的光催化性能, 并分析该气相光催化反应的机理, 在紫外照射条件下异丙醇先氧化为丙酮再被氧化为CO₂.当总溅射气压为2.0 Pa、Ar/O₂流量比为1:1时, 溅射所得TiO₂薄膜具备最优光催化活性并可在IPA降解反应中保持较高的催化活性和稳定性.     

High-pressure transitions in MgAl2O4 and a new high-pressure phase of Mg2Al2O5

Phase transitions in MgAl₂O₄ were examined at 21-27 GPa and 1400-2500 °C using a multianvil apparatus. A mixture of MgO and Al₂O₃ corundum that are high-pressure dissociation products of MgAl₂O₄ spinel combines into calcium-ferrite type MgAl₂O₄ at 26-27 GPa and 1400-2000 °C. At temperature above 2000 °C at pressure below 25.5 GPa, a mixture of Al₂O₃ corundum and a new phase with Mg₂Al₂O₅ composition is stable. The transition boundary between the two fields has a strongly negative pressure-temperature slope. Structure analysis and Rietveld refinement on the basis of the powder X-ray diffraction profile of the Mg₂Al₂O₅ phase indicated that the phase represented a new structure type with orthorhombic symmetry (Pbam), and the lattice parameters were determined as a=9.3710(6) Å, b=12.1952(6) Å, c=2.7916(2) Å, V=319.03(3) Å³, Z=4. The structure consists of edge-sharing and corner-sharing (Mg, Al)O₆ octahedra, and contains chains of edge-sharing octahedra running along the c-axis. A part of Mg atoms are accommodated in six-coordinated trigonal prism sites in tunnels surrounded by the chains of edge-sharing (Mg, Al)O₆ octahedra. The structure is related with that of ludwigite (Mg, Fe²⁺)₂(Fe³⁺, Al)(BO₃)O₂. The molar volume of the Mg₂Al₂O₅ phase is smaller by 0.18% than sum of molar volumes of 2MgO and Al₂O₃ corundum. High-pressure dissociation to the mixture of corundum-type phase and the phase with ludwigite-related structure has been found only in MgAl₂O₄ among various A²⁺B³⁺₂O₄ compounds.     

Comparative study on the synthesis, photoluminescence and application in InGaN-based light-emitting diodes of TAG:Ce phosphors

Cerium-doped terbium aluminum garnet phosphors, Tb₃Al₅O₁₂:Ce³⁺ (TAG:Ce³⁺), were prepared with different methods: co-precipitation (CP), half dry-half wet (HDHW), sol-combustion (SC) and Pechini method plus conventional solid state reaction (SS) method. Comparative study on the phase-formation, particle size, morphologies and luminescent characteristics of the phosphors synthesized with different methods was carried out by means of XRD, FE-SEM and photoluminescence (PL) analysis and SC method was confirmed by the comparison of the results to be an easy and an effective process for preparing efficient and nano-sized Tb₃Al₅O₁₂:Ce³⁺ phosphors. Various factors influencing particle size, morphology and PL of the phosphors, such as precursor preparation, reaction temperature and heating time, were also investigated. Light-emitting diodes (LEDs) were fabricated with each phosphor and a ∼460 nm emitting InGaN chip. The LEDs from SS, HDHW and CP exhibit strong white emission while those from SC and Pechini emit yellow, revealing that the emission characteristics of LEDs are influenced not only by the morphology and the particle size of the phosphors, but also by the preparing process of the phosphors.