β-Carotene Inhibits Expression of Matrix Metalloproteinase-10 and Invasion in Helicobacter pylori-Infected Gastric Epithelial Cells

Matrix metalloproteinases (MMPs), key molecules of cancer invasion and metastasis, degrade the extracellular matrix and cell–cell adhesion molecules. MMP-10 plays a crucial role in Helicobacter pylori-induced cell-invasion. The mitogen-activated protein kinase (MAPK) signaling pathway, which activates activator protein-1 (AP-1), is known to mediate MMP expression. Infection with H. pylori, a Gram-negative bacterium, is associated with gastric cancer development. A toxic factor induced by H. pylori infection is reactive oxygen species (ROS), which activate MAPK signaling in gastric epithelial cells. Peroxisome proliferator-activated receptor γ (PPAR-γ) mediates the expression of antioxidant enzymes including catalase. β-Carotene, a red-orange pigment, exerts antioxidant and anti-inflammatory properties. We aimed to investigate whether β-carotene inhibits H. pylori-induced MMP expression and cell invasion in gastric epithelial AGS (gastric adenocarcinoma) cells. We found that H. pylori induced MMP-10 expression and increased cell invasion via the activation of MAPKs and AP-1 in gastric epithelial cells. Specific inhibitors of MAPKs suppressed H. pylori-induced MMP-10 expression, suggesting that H. pylori induces MMP-10 expression through MAPKs. β-Carotene inhibited the H. pylori-induced activation of MAPKs and AP-1, expression of MMP-10, and cell invasion. Additionally, it promoted the expression of PPAR-γ and catalase, which reduced ROS levels in H. pylori-infected cells. In conclusion, β-carotene exerts an inhibitory effect on MAPK-mediated MMP-10 expression and cell invasion by increasing PPAR-γ-mediated catalase expression and reducing ROS levels in H. pylori-infected gastric epithelial cells.     

Impact of Matrix Metalloproteinase-9 during Periodontitis and Cardiovascular Diseases

Matrix metalloproteinase-9 (MMP-9) has been shown to play a key role in endothelial function and perhaps pivotal in the correlation between periodontal disease and cardiovascular disease (CVD). For the study, the impact of MMP-9 of periodontitis and CVD on serum and saliva concentrations was analyzed. For the study patients with periodontitis (n = 31), CVD (n = 31), periodontitis + CVD (n = 31), and healthy patients (n = 31) were enrolled. Clinical and demographic characteristics as well as serum and salivary MMP-9 were evaluated. MMP-9 concentrations in serum and saliva were statistically elevated in patients with CVD (p < 0.01) and in patients with periodontitis plus CVD (p < 0.001) compared to patients with periodontitis and healthy subjects. Multivariate regression analysis showed that c-reactive protein (hs-CRP) was the only significant predictor for MMP-9 serum (p < 0.001), whereas hs-CRP (p < 0.001) and total cholesterol (p = 0.029) were the statistically significant salivary MMP-9 predictors. This study evidenced that patients with CVD and periodontitis + CVD presented elevated MMP-9 concentrations in serum and saliva compared to patients with periodontitis and healthy subjects. Furthermore, hs-CRP was a negative predictor of serum and salivary MMP-9.     

Matrix Isolation Spectroscopic and Relativistic Quantum Chemical Study of Molecular Platinum Fluorides PtFn (n=1–6) Reveals Magnetic Bistability of PtF4

Molecular platinum fluorides PtF_n, n=1–6, are prepared by two different routes, photo-initiated fluorine elimination from PtF₆ embedded in solid noble-gas matrices, and the reaction of elemental fluorine with laser-ablated platinum atoms. IR spectra of the reaction products isolated in rare-gas matrices under cryogenic conditions provide, for the first time, experimental vibrational frequencies of molecular PtF₃, PtF₄ and PtF₅. Photolysis of PtF₆ enabled a highly efficient and almost quantitative formation of molecular PtF₄, whereas both PtF₅ and PtF₃ were formed simultaneously by subsequent UV irradiation of PtF₄. The vibrational spectra of these molecular platinum fluorides were assigned with the help of one- and two-component quasirelativistic DFT computation to account for scalar relativistic and spin–orbit coupling effects. Competing Jahn-Teller and spin–orbit coupling effects result in a magnetic bistability of PtF₄, for which a spin-triplet (³B_2g, D_2h) coexists with an electronic singlet state (¹A_1g, D_4h) in solid neon matrices.     

Generation and Identification of the Linear OCBNO and OBNCO Molecules with 24 Valence Electrons

Two structural isomers containing five second-row element atoms with 24 valence electrons were generated and identified by matrix-isolation IR spectroscopy and quantum chemical calculations. The OCBNO complex, which is produced by the reaction of boron atoms with mixtures of carbon monoxide and nitric oxide in solid neon, rearranges to the more stable OBNCO isomer on UV excitation. Bonding analysis indicates that the OCBNO complex is best described by the bonding interactions between a triplet-state boron cation with an electron configuration of (2s)⁰(2p_σ)⁰(2p_π)² and the CO/NO⁻ ligands in the triplet state forming two degenerate electron-sharing π bonds and two ligand-to-boron dative σ bonds.     

气相色谱-质谱法检测益智药材中16种多环芳烃

建立了气相色谱-质谱联用技术同时测定益智药材中16种多环芳烃(PAHs)的分析方法。最佳萃取条件为：取样品2.0 g,加入同位素内标后用无水乙醇、水混合溶解,以10 mL正己烷提取;提取液先过Florisil柱固相萃取,经氢氧化钾-乙醇溶液皂化,多环芳烃分子印迹柱固相萃取后,以5 mL二氯甲烷-正己烷(1∶1,体积比)进行洗脱;采用DB-EUPAH毛细管色谱柱进行分离,内标标准曲线法定量测定。在此条件下,16种多环芳烃的线性范围为1.0~200.0 μg/L(r2 ≥ 0.992 5);检出限(S/N=3)为0.3~1.0 μg/kg;在不同浓度(1、3、10 μg/kg)基质加标条件下,苯并［c］芴(BcFL)的加标回收率为65.4%~72.8%,日内相对标准偏差(RSD,n=6)为6.0%~7.4%,日间RSD(n=6)为8.5%;其他15种多环芳烃的加标回收率为89.3%~116%,日内RSD(n=6)为0.10%~6.1%,日间RSD(n=6)为1.2%~7.5%。该方法的前处理净化效果好、灵敏度高、准确度高,适用于益智药材中16种多环芳烃的定量检测。     

脑胶质瘤磁共振弥散张量成像定量参数与VEGF、MMP-9表达的相关性

本研究旨在分析脑胶质瘤患者的磁共振弥散张量成像(DTI)参数与病变组织血管内皮生长因子(VEGF)和基质金属蛋白酶-9(MMP-9)表达的相关性,以及DTI参数对脑胶质瘤进行分级诊断的价值。根据病理分级将102例脑胶质瘤患者分为低级别组(47例)和高级别组(55例),均行MRI和DTI检查,定量测定表观弥散系数(ADC)、各向异性分数(FA)、相对ADC(rADC)、相对FA(rFA)值及相对轴向扩散系数(rAD)值;用免疫组化法检测VEGF和MMP-9表达情况。结果显示,高级别组患者的rADC、ADC、rAD、FA、rFA均低于低级别组(P<0.05);高级别组患者的VEGF和MMP-9阳性表达均高于低级别组(P<0.05)。rADC、ADC、rAD、FA、rFA与VEGF和MMP-9表达均呈负相关(P<0.05);rADC、ADC、rAD、FA、rFA对脑胶质瘤分级诊断的AUC均具有一定诊断价值(P<0.05)。本研究结果提示DTI定量参数与脑胶质瘤VEGF和MMP-9表达具有相关性,且有助于脑胶质瘤的分级诊断。     

Substituent Effects on EI-MS Fragmentation Patterns of 5-Allyloxy-1-aryl-tetrazoles and 4-Allyl-1-aryl-tetrazole-5-ones; Correlation with UV-Induced Fragmentation Channels

1,4- and 1,5-disubstituted tetrazoles possess enriched structures and versatile chemistry, representing a challenge for chemists. In the present work, we unravel the fragmentation patterns of a chemically diverse range of 5-allyloxy-1-aryl-tetrazoles and 4-allyl-1-aryl-tetrazolole-5-ones when subjected to electron impact mass spectrometry (EI-MS) and investigate the correlation with the UV-induced fragmentation channels of the matrix-isolated tetrazole derivatives. Our results indicate that the fragmentation pathways of the selected tetrazoles in EI-MS are highly influenced by the electronic effects induced by substitution. Multiple pathways can be envisaged to explain the mechanisms of fragmentation, frequently awarding common final species, namely arylisocyanate, arylazide, arylnitrene, isocyanic acid and hydrogen azide radical cations, as well as allyl/aryl cations. The identified fragments are consistent with those found in previous investigations concerning the photochemical stability of the same class of molecules. This parallelism showcases a similarity in the behaviour of tetrazoles under EI-MS and UV-irradiation in the inert environment of cryogenic matrices of noble gases, providing efficient tools for reactivity predictions, whether for analytical ends or more in-depth studies. Theoretical calculations provide complementary information to articulate predictions of resulting products.     

基体分离-电感耦合等离子体原子发射光谱法 测定精铋中10种杂质元素

试验采用电感耦合等离子体发射光谱法测定精铋中Cd、Co、Cu、Fe、Mg、Mn、Ni、Pb、Ti、Zn十种杂质元素,样品用优级纯硝酸溶解,往60℃左右的溶液中,滴加氨水(1+1),控制pH值在3.0~4.0。考察了温度、酸度、沉降时间对铋的去除率和对检测结果的影响。根据分析线的选择原则,结合待测元素的检测范围,选择无干扰、峰形对称、灵敏度适中的谱线作为分析线Cd 228.802nm、Co 237.862nm、Cu 324.754nm、Fe 259.940nm、Mg 279.553nm、Mn 257.610nm、Ni 231.604nm、Pb 182.205nm、Ti 323.452nm、Zn 213.856nm。各元素的质量浓度在一定范围内与其发射强度呈线性,校准曲线的线性相关系数均大于0.9997,方法中各元素检出限为0.002μg/g~0.253μg/g。?按照实验方法测定精铋实际样品,结果的相对标准偏差(RSD,n=9)为2.5%~9.8%,加标回收率为95.0%~102.2%,满足检测要求。     

Environmental effects on fibre reinforced polymeric composites: Evolving reasons and remarks on interfacial strength and stability

The interface between fibre and matrix of fibrous polymeric composites is most critical and decisive in maintaining sustainability, durability and also reliability of this potential material, but unfortunately a comprehensive conclusion is yet to meet the label of confidence for the engineering viability. Fiber reinforced polymer (FRP) composites are being accepted and also utilized as better and reliable alternative materials for repairing and/or replacing conventional materials, starting from tiny objects to mega structure in various engineering applications. The promise and potential of these materials are sometimes threatened in speedy replacement of conventional materials because of their inhomogeneities and inherent susceptibility to degradation due to moist and thermal environments. Environmental conditioning is traditionally believed to be a physical phenomenon but present literature has revealed that the interdiffusion between fiber and polymer matrix resin comprises of physical, chemical, mechanical, physico-chemical and mechano-chemical phenomena. The failure and fracture behavior at ambient conditions itself is a complex phenomenon till at present. The service conditions which are mostly hygrothermal in nature, along with a variation of applied loads make the mechanical behavior nearly unpredictable, far off from conclusions in evaluating the short term as well as long term durability and reliability of FRPs. It is essential to accurately simulate the initial and subsequent evolution process of this kind of damage phenomena, in order to explore the full potential of the mechanical properties of composite laminates. The present review has emphasized the need of complying scattered as well as limited literature on this front, and has focused on creating the urgency to highlight the importance of judicious uses of these materials with minimum safety factors with an aim to achieving lighter weight in enhancing specific properties.