Morphine-induced conditioned place preference in mice: Metabolomic profiling of brain tissue to find “molecular switch” of drug abuse by gas chromatography/mass spectrometry

Conditioned place preference (CPP) is a widely used model to explore the mechanism of context-dependent learning. In this work, we developed a GC–MS method to investigate the metabolites in mice brain which was used to study the mechanism of context-dependent learning associated with rewarding effect of morphine. Metabolites were extracted from brain tissues and derivatized followed by analysis by gas chromatography/mass spectrometry (GC–MS). In total, 69 peaks were identified as known compounds. By a Wilcoxon ran sum test with p value ≤0.05, 21 metabolites were selected and considered as the potential biomarkers of morphine in mice brain. Using principal component analysis (PCA) and receiver-operator characteristic (ROC) curves, a model was constructed with a combination of these 21 metabolic markers. Multivariate statistics of the model yielded separation between the two groups with an area under the curve value of 0.947. Some metabolites were further discussed in detail about their pathway. Results showed that our technique can be successfully applied to profile for biomarkers and in understanding molecular mechanisms of drug abuse.     

HPLC-MS/MS enantioseparation of triazole fungicides using polysaccharide-based stationary phases

The enantiomeric separation of 21 triazole fungicides was carried out on four polysaccharide-derived chiral stationary phases in the reversed phase separation mode using high performance liquid chromatography coupled with tandem mass spectrometry. All fungicides were detected in electrospray ionization (ESI) positive mode with selected reaction monitoring (SRM). Complete enantioseparation was achieved for 21 fungicides except for difenoconazole based on cellulose tris (3,5-dimethylphenylcarbamate) and cellulose tris (3-chloro-4-methylphenyl carbamate) columns by optimizing experimental conditions including mobile phase and column temperature. Mobile phase was 0.1% formic acid aqueous solution mixed with methanol or acetonitrile in different proportions. Among all the fungicides, 15 with two enantiomers and three with four stereoisomers (bitertanol, bromuconazole, and cyproconazole) were successfully separated at 25°C. Enantioseparation for the other three fungicides (propiconazole, triadimenol, and difenoconazole) with four stereoisomers could be achieved by changing the column temperature from 10 to 40°C. Propiconazole and triadimenol were enantioseparated on baseline at 40 and at 35°C, respectively, and difenoconazole was enantioseparated partially with the R(s) > 1.1 at 25°C. Moreover, linearities and limits of detection (LODs) of 21 fungicides except for difenoconazole were studied, showing coefficients of determination (R(2)) higher than 0.99 and LODs lower than 2.5 μg/L.     

钨酸钠/冰乙酸/过氧化氢作用下聚丁二烯橡胶环氧化及降解行为研究

本文研究了在钨酸钠/冰乙酸/过氧化氢催化体系作用下聚丁二烯橡胶环氧化及降解行为.采用红外(FT-IR)、核磁(1H-NMR)和气相凝胶渗透色谱(GPC)对降解产物进行了表征,结果表明60℃反应24h,聚丁二烯橡胶环氧度为21.27％,而其分子量没有明显降低.     

Copper‐Catalyzed Aerobic Oxidative Reaction of Sulfonyl Hydrazides with Alcohols: An Easy Access to Sulfinates

A Cu‐catalyzed aerobic oxidative reaction between sulfonyl hydrazides and alcohols has been developed. In this reaction, sulfonyl hydrazides act as the sulfinic acid precursors to react with alcohols, resulting in sulfinic esters with up to 72 % yield. This catalytic system tolerates a wide range of sulfonyl hydrazide substrates, and represents a new strategy for the transformation of readily available sulfonyl hydrazides.     

The hydration properties of carboxybetaine zwitterion brushes

Combined quantum mechanical calculations and classical molecular dynamics simulations were conducted to investigate the hydration properties of carboxybetaine zwitterion brushes with varying separation distances between the quaternary ammonium cation and carboxylic anion. The brushes consist of zwitterion trimers and are investigated to mimic interacting zwitterion chains grafted on a substrate as well as polymers with interacting zwitterion side chains. Our results show that the values of both positive and negative charges, their separation distances as well as chain interactions appear to play a critical role in the hydration properties of the zwitterions. The overall hydration property of these zwitterions is dictated by the competition between the strong hydration of the charged groups and the dehydration of the hydrocarbon chains. The strongest hydration occurs when the ? CH₂? unit in the hydrocarbon chain reaches 6–8 for these trimers. Further increase in the hydrocarbon chain length to 10–14 leads to significant and sudden dehydration of the trimers. The water structure and the water residence time surrounding the zwitterions also demonstrate substantial alteration at this length scale. This hydrophilic‐to‐hydrophobic transition is induced by the hydrophobic interactions of the trimer chains. Our hydration results could explain the observed trend of the superiority of the methylated carbohydrates and poly(ethylene glycol) as antifouling materials compared to corresponding hydroxyl‐terminated compounds. © 2015 Wiley Periodicals, Inc.     

TRIM45 causes neuronal damage by aggravating microglia-mediated neuroinflammation upon cerebral ischemia and reperfusion injury

Excessive and unresolved neuroinflammation is a key component of the pathological cascade in brain injuries such as ischemic stroke. Tripartite motif-containing 45 (TRIM45) is a ubiquitin E3 ligase involved in various critical biological processes. However, the role of TRIM45 in cerebral ischemia remains unknown. Here, we found that the TRIM45 protein was highly expressed in the peri-infarct areas of mice subjected to cerebral ischemia and reperfusion injury induced by middle cerebral artery occlusion. This study systemically evaluated the putative role of TRIM45 in the regulation of neuroinflammation during ischemic injury and the potential underlying mechanisms. We found that TRIM45 knockdown significantly decreased proinflammatory cytokine and chemokine production in primary cultured microglia challenged with oxygen-glucose deprivation and reoxygenation (OGD/R) treatment. Mechanistically, we demonstrated that TRIM45 constitutively interacted with TAB2 and consequently facilitated the Lys-63-linked polyubiquitination of TAB2, leading to the formation of the TAB1–TAK1–TAB2 complex and activation of TAK1, which was ultimately followed by activation of the nuclear factor-kappa B (NF-κB) signaling pathway. In an in vitro coculture Transwell system, downregulation of TRIM45 expression also inhibited the OGD/R-induced activation of microglia and alleviated neuronal apoptosis. More importantly, microglia-specific knockdown of TRIM45 in mice significantly reduced the infarct size, mitigated neurological deficit scores, and improved cognitive function after ischemic stroke. Taken together, our study reveals that the TRIM45–TAB2 axis is a crucial checkpoint that controls NF-κB signaling in microglia during cerebral ischemia and reperfusion injury. Therefore, targeting TRIM45 may be an attractive therapeutic strategy.Subject terms: Cell death in the nervous system, Stroke     

Flexible Liquid Crystal Polymer Technologies from Microwave to Terahertz Frequencies

With the emergence of fifth-generation (5G) cellular networks, millimeter-wave (mmW) and terahertz (THz) frequencies have attracted ever-growing interest for advanced wireless applications. The traditional printed circuit board materials have become uncompetitive at such high frequencies due to their high dielectric loss and large water absorption rates. As a promising high-frequency alternative, liquid crystal polymers (LCPs) have been widely investigated for use in circuit devices, chip integration, and module packaging over the last decade due to their low loss tangent up to 1.8 THz and good hermeticity. The previous review articles have summarized the chemical properties of LCP films, flexible LCP antennas, and LCP-based antenna-in-package and system-in-package technologies for 5G applications, although these articles did not discuss synthetic LCP technologies. In addition to wireless applications, the attractive mechanical, chemical, and thermal properties of LCP films enable interesting applications in micro-electro-mechanical systems (MEMS), biomedical electronics, and microfluidics, which have not been summarized to date. Here, a comprehensive review of flexible LCP technologies covering electric circuits, antennas, integration and packaging technologies, front-end modules, MEMS, biomedical devices, and microfluidics from microwave to THz frequencies is presented for the first time, which gives a broad introduction for those outside or just entering the field and provides perspective and breadth for those who are well established in the field.     

Cole-Cole方程参数对细胞介电频谱的影响

为探讨Cole-Cole方程8个参数(Δε1,Δε2,εh,κl,f1,f2,β1,β2)对细胞介电频谱的影响,采用改变单个参数,固定其他参数的方法,观察介电频谱的变化.结果显示:Δε1影响低频介电频谱和Cole-Cole(ε′)图;Δε2影响高频介电频谱、Cole-Cole(ε′)图和Cole-Cole(κ′)图;εh影响ε′(f)、Cole-Cole(ε′)图和tgδ(f);κl对κ′(f)和Cole-Cole(κ′)图有影响;f1影响低频介电频谱;f2影响高频介电频谱;β1影响Cole-Cole(ε′)和tgδ(f);β2对高频介电频谱有影响.可见Cole-Cole方程作为细胞介电频谱的数学模型,其参数变化有规律可循.     

A Characterization of Maximally Entangled Two-Qubit States

As already known by Rana’s result, all eigenvalues of any partial-transposed bipartite state fall within the closed interval [−12,1]. In this note, we study a family of bipartite quantum states where the minimal eigenvalues of partial-transposed states are −12. For a two-qubit system, we find that the minimal eigenvalue of its partial-transposed state is −12 if and only if such a two-qubit state is maximally entangled. However this result does not hold in general for a two-qudit system when the dimensions of the underlying space are larger than two.