Composition of clove (Syzygium aromaticum) bud oil extracted using carbon dioxide

Analysis of clove (Syzygium aromaticum L) bud oil extracted with liquid and supercritical carbon dioxide shows significant qualitative and quantitative compositional differences compared with oil obtained by the conventional hydrodistillation process. The parameters of pressure, temperature, contact time etc, and also the clove oil components, affect the extraction of the bud flavour from the spice.     

Revisable knowledge discovery in databases

This article introduces the idea of using nonmonotonic inheritance networks for the storage and maintenance of knowledge discovered in data (revisable knowledge discovery in databases). While existing data mining strategies for knowledge discovery in databases typically involve initial structuring through the use of identification trees and the subsequent extraction of rules from these trees for use in rule-based expert systems, such strategies have difficulty in coping with additional information which may conflict with that already used for the automatic generation of rules. In the worst case, the entire automatic sequence may have to be repeated. If nonmonotonic inheritance networks are used instead of rules for storing knowledge discovered in databases, additional conflicting information can be inserted directly into such structures, thereby bypassing the need for recompilation. © 1996 John Wiley & Sons, Inc.     

Pharmacological Inhibition of Spermine Oxidase Suppresses Excitotoxicity Induced Neuroinflammation in Mouse Retina

Polyamine oxidation plays a major role in neurodegenerative diseases. Previous studies from our laboratory demonstrated that spermine oxidase (SMOX, a member of the polyamine oxidase family) inhibition using MDL 72527 reduced neurodegeneration in models of retinal excitotoxicity and diabetic retinopathy. However, the mechanisms behind the neuroprotection offered by SMOX inhibition are not completely studied. Utilizing the experimental model of retinal excitotoxicity, the present study determined the impact of SMOX blockade in retinal neuroinflammation. Our results demonstrated upregulation in the number of cells positive for Iba-1 (ionized calcium-binding adaptor molecule 1), CD (Cluster Differentiation) 68, and CD16/32 in excitotoxicity-induced retinas, while MDL 72527 treatment reduced these changes, along with increases in the number of cells positive for Arginase1 and CD206. When retinal excitotoxicity upregulated several pro-inflammatory genes, MDL 72527 treatment reduced many of them and increased anti-inflammatory genes. Furthermore, SMOX inhibition upregulated antioxidant signaling (indicated by elevated Nrf2 and HO-1 levels) and reduced protein-conjugated acrolein in excitotoxic retinas. In vitro studies using C8-B4 cells showed changes in cellular morphology and increased reactive oxygen species formation in response to acrolein (a product of SMOX activity) treatment. Overall, our findings indicate that the inhibition SMOX pathway reduced neuroinflammation and upregulated antioxidant signaling in the retina.     

The Impact of International Crises on Maritime Transportation Based Global Value Chains

Networks and Spatial Economics - International trade has evolved into global value chains, a worldwide network highly impacted by global crises. Since maritime transportation is the most important...     

锌-三氧化二铬复合镀层的特性

采用由氧化锌12g/L、氢氧化钠94 g/L、2-氨基-3-羧基吡啶4.2 g/L、四乙烯五胺17g/L、三乙醇胺2g/L、专利表面活性剂0.5 g/L及碳三氧化二铬(粒径2μm)0～ 11 g/L组成的镀液,于温度50℃、pH 6.5和电流密度4A/dm2的条件下,在低碳钢上电镀Zn-Cr2O3复合镀层.其显微硬度采...     

Fluorine in Drug Design: A Case Study with Fluoroanisoles

Anisole and fluoroanisoles display distinct conformational preferences, as evident from a survey of their crystal structures. In addition to altering the free ligand conformation, various degrees of fluorination have a strong impact on physicochemical and pharmacokinetic properties. Analysis of anisole and fluoroanisole matched molecular pairs in the Pfizer corporate database reveals interesting trends: 1) PhOCF₃ increases log D by ～1 log unit over PhOCH₃ compounds; 2) PhOCF₃ shows lower passive permeability despite its higher lipophilicity; and 3) PhOCF₃ does not appreciably improve metabolic stability over PhOCH₃. Emerging from the investigation, difluoroanisole (PhOCF₂H) strikes a better balance of properties with noticeable advantages of log D and transcellular permeability over PhOCF₃. Synthetic assessment illustrates that the routes to access difluoroanisoles are often more straightforward than those for trifluoroanisoles. Whereas replacing PhOCH₃ with PhOCF₃ is a common tactic to optimize ADME properties, our analysis suggests PhOCF₂H may be a more attractive alternative, and greater exploitation of this motif is recommended.     

Thermal Stability, Phase Evolution, and Crystallization in Si-B-C-N Ceramics Derived from a Polyborosilazane Precursor

Amorphous Si-B-C-N ceramic powder samples obtained by thermolysis of boron-modified polysilazane, {B[C₂H₄Si(H)NH]₃} _n , were isothermally annealed at different temperatures (1400–1800°C) and hold times (3, 10, 30, and 100 h). A qualitative and semiquantitative analysis of the crystallization behavior of the materials was performed using X-ray diffraction (XRD). The phase evolution was additionally followed by ¹¹B and ²⁹Si MAS NMR as well as by FT-IR spectroscopy in transmission and diffuse reflection (DRIFTS) modes. Bulk chemical analyses of selected samples were performed to determine changes in the chemistry/phase composition of the materials. It was observed that silicon carbide is the first phase to nucleate around 1400–1500°C, whereas silicon nitride nucleates at and above 1700°C. Crystallization accelerates with increasing annealing temperature and proceeds with increasing annealing time. Furthermore, the surface area of the powders strongly influences the thermal stability of silicon nitride and thus controls overall chemical and phase composition of the materials on thermal treatment.     

Crystalline selenite substituted carbonated hydroxyapatite nanorods: Synthesis,characterization, evaluation of bioactivity and cytotoxicity

Synthesis of pure and selenite substituted hydroxyapatites (HAP and Se‐HAP with 0.02–0.10 Se) by sol–gel method and evaluation of their morphological features, nature of functional groups, phase purity, in vitro bioactivity and cytotoxicity are addressed. Spectral studies confirm the incorporation of selenite into the HAP lattice, accompanied by an increase in CO₃^2? content to maintain the charge imbalance following replacement of P⁵⁺ with Se⁴⁺, thus making the formation of selenite substituted carbonated HAP. Selenite substitution in the HAP lattice has led to a higher crystallinity and increased the crystallite size. The morphology of HAP is changed from sphere to rod‐like structure upon substitution by selenite and the size of the rod is increased with an increase in the selenite content. Among the Se‐HAPs, a better in vitro bioactivity and cell viability are observed for 0.02 Se‐HAP and 0.04 Se‐HAP while the trend is reversed when the extent of selenite substitution becomes higher.     

Time resolved study of oriented crystallisation of poly(lactic acid) during rapid tensile deformation

Poly(l-lactic acid) with 4% d-lactic acid comonomer has been drawn in the amorphous state at 80, 90, 100, 110 and 120 °C at an extension rate of 4 s⁻¹ while simultaneously recording WAXS and SAXS patterns at intervals of 0.12 s. At 80, 90 and 100 °C, crystallisation is very rapid (1-4 s⁻¹) and follows a first order transformation process to give highly oriented crystals. SAXS patterns were barely detectable at these temperatures despite fractional crystallinity of ∼0.2. At 110 and 120 °C, crystallisation was very slow (∼0.01 s⁻¹) and gave rise to crystals with a lower degree of orientation. After eventual crystallisation at 120 °C, a two-point SAXS pattern develops with narrow lateral spread, suggesting ‘shish kebab’ morphology. When the 80 °C drawn sample was annealed at 120 °C, a strong four point SAXS pattern develops. The change in drawing and crystallisation behaviour at higher draw temperature is attributed to the onset of chain retraction relaxation processes. The WAXS fibre pattern after annealing shows sampling on intermediate layer lines that is consistent with the α crystal form with a 10₃ helix. However, prior to annealing, sampling indicates a different, less defined helical configuration.