"Handbook of Organic Chemistry"

本书由Dean,J.A.编著,由McGraw—Hill在1987年出版。它以表格形式按英文字母顺序给出了4000种有机化合物及与有机化学相关的无机化合物的名称、结构式、分子量、Beilstein文献、密度、折光指数、熔点、沸点、闪点和溶解度。其中一部分还给出了物理性质(包括粘度、介电常数、偶极矩和表面张力)、     

Special Issue of "Biopolymers"

Biopolymers have more and more important relations with human life.The research on biopolymers involves such fields as chemistry,biology and medicine.In term of source,the biopolymers comprise natural biopolymers and synthetic biopolymers.The development of synthetic biopolymers,especially biodegradable polymers,has enriched the structure,properties and varieties of biopolymers,promoted their applications in many areas such as sutures,bone fixation parts,temporary supporting tubes,drug controlled release carriers and tissue engineering scaffolds.     

"Tables of Spectral Data for Structure Determination of Organic Compounds"

《有机化合物结构确定用光谱数据表》第2版(英文)由德国施普林格出版社于1989年出版。该书以表格和框图的形式给出了大量化合物的~(13)C-核磁共振波谱、红外光谱、质谱及电子激发光谱数据,为有机化合物结构的确定提供了重要依据。可供有机化学分析化学专业人员参考。本书已由世界图书出版公司购得重印权,将在     

Cyclization of α-furylmethyl derivatives of linalool by "activated" DMSO

The cyclization of two stereoisomeric -furylmethyl derivatives of linalool initiated by "activated" DMSO leads to the corresponding substituted limonene in low yield. The stereochemistry of these products was not established.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow, B-334. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 2, pp. 471–473, February, 1992.     

Estimation of the homogeneity of reference materials by SS–ETAAS and use of the "tape-sandwich" sample-introduction technique

The so called "tape sandwich", a novel sample-introduction technique developed for SS-ETAAS, has been employed in a study of the microheterogeneity of some biological CRM. Pb, Cd, and Cr were measured by use of a laboratory-assembled instrument with graphite-cup atomizer. Aqueous standards were found satisfactory for calibration. The average mass of sub-samples atomised was in the range 0.250-0.660 mg+/-30%. The relative sampling error found for the CRM investigated varied from 15-34%. Calculated relative homogeneity constants of the order of 4-21 mg(1/2) were obtained, and were reduced considerably by reduction of the particle size. The minimum sample sizes representative of the CRM were, with one exception, much lower (11-75 mg) than those recommended in the documentation accompanying the standards (100-200 mg). In a Chinese hair reference sample Cr data were normally distributed but the presence of nuggets was observed for Cd and Pb; this was associated with severe radial and longitudinal gradients of these elements in hair.     

A biomass based photonic crystal made of "konjac tofu"

Konjac tofu is a traditional Chinese food whose main ingredient is the water-soluble polysaccharide from konjac tubers-konjac glucomannan(KGM).Herein we report an interpenetrating double network polymeric film by crosslinking KGM and polyvinyl alcohol(PVA) with glutaraldehyde under acidic conditions.PVA was introduced into the hydrogel system as a hard skeleton,which not only maintained the biocompatibility of KGM,but also gave the hydrogel superior mechanical properties and solvent resistance.Implanting a colloidal array inside the above film,we obtained a new type of biomass based photonic crystal that is sensitive to a variety of physical and chemical stimulus,especially for methanol.This photonic crystal responds to metha nol and methanol vapo r,and has the ability to detect methanol in gasoline,which has a good application prospect.     

Is a "homogeneous" description of dynamic heterogeneities possible?

We study the simplest model of dynamic heterogeneities in glass forming liquids: one-spin facilitated kinetic Ising model introduced by Fredrickson and Andersen [G. H. Fredrickson and H. C. Andersen, Phys. Rev. Lett. 53, 1244 (1984); J. Chem. Phys. 83, 5822 (1985)]. We show that the low-temperature, long-time behavior of the density autocorrelation function predicted by a scaling approach can be obtained from a self-consistent mode-couplinglike approximation.     

Density dependence of the "escape" yield of hydrated electrons in the low-LET radiolysis of supercritical water at 400 °C

The "spur lifetime" (τ(s)) in the low-linear energy transfer (LET) radiolysis of supercritical water (SCW) at 400 °C has been determined as a function of water density by using a simple model of energy deposition initially in spurs, followed by the random diffusion (Brownian motion) of the species formed until spur expansion is complete. The values of τ(s) are found to decrease from ～5.0 × 10(-6) to 5.0 × 10(-8) s over the density range from 0.15 to 0.6 g cm(-3). Using Monte-Carlo simulations, our calculated density dependence of the "escape" hydrated electron (e(aq)(-)) yield (i.e., at time τ(s)) reproduces fairly well Bartels and co-workers' scavenged e(aq)(-) yield data, suggesting that these data may have been measured at times close to τ(s).     

Simultaneous Enhancement of Toughness and Strength of Stretched iPP Film via Tiny Amount of β-Nucleating Agent under "Shear-free"Melt-extrusion

Herein,isotactic polypropylene films with small β-nucleating agent content were fabricated via a melt-extrusion-stretched technology with intended "shear-free" in barrel and die.Compared with neat films,the tensile strength,elongation at break and strain energy density at break of iPP film with 0.05 wt％ β-nucleating agent are significantly improved by 13.8％,39.6％ and 90.6％,respectively,indicating the simultaneously enhanced toughness and strength.Additionally,the β-crystal content gradually increases with increasing β-NA content,while the relative total daughter content of α-and β-crystal exhibits opposite tendency.Moreover,nucleation and crystal growth induced by various β-NA contents are different.This work proves an efficient strategy to enhance mechanical properties of isotactic polypropylene film via controlling elongation flow and addition of appropriate β-NA content.     

Origin of activation barriers in the dimerization of neutral radicals: a "nonperfect synchronization" effect?

Dimerizations of delocalized neutral radicals may be endowed with quite significant activation barriers. The origin of these barriers is discussed in terms of a model that emphasizes the role of localization of the unpaired radical upon bond formation. Several examples are given in which the model is compared with the results of quantum chemical calculations including the coupling of allyl radicals and of benzyl radicals at various possible carbon sites. The dimerization behavior of radicals in the NADH family is also examined. The connection between the reasons that underlay the existence of the activation barrier and the principle of "nonperfect synchronization" is discussed. The dimerization of conjugated radicals indeed offers a precious example that can be used to decipher the reasons behind these behaviors, being devoid of the ambiguities arising from the simultaneous involvement of ionic and covalent states, significant solvent reorganization, and the contribution of extensive proton tunneling, in the mostly discussed case of proton transfer at carbon.     

Volatiles of French ferns and "fougère" scent in perfumery

Six French ferns were investigated for volatile organic compounds (VOC) by GC-MS using organic solvent extraction. Seventy-seven VOC biosynthesized from the shikimic, lipidic and terpenic pathways, including isoprenoid derivatives, were identified from these putative natural resources. Asplenium trichomanes subsp. trichomanes contained mainly polyketides with an oily or waxy odor. (E)-2-Hexenal and (Z)-3-hexenol, responsible for the "green odor", were found in high contents in Polystichum setiferum, Dryopteris dilatata and Phegopteris connectilis. In the last, 7.4% of coumarin with a cut hay scent was highlighted from the volatile fraction. (E)-3-Hexenoic acid and (E)-2-hexenoic acid, both with herbal and fruity notes, were identified in Gymnocarpium dryopteris and Pteridium aquilinum. 1-Octen-3-ol, well-known for its mushroom-like odor, was abundant in all analyzed French ferns. While the "fougère" fragrance is claimed by the perfumers to be a fantasy scent, coumarin, (E)-2-hexenal, (Z)-3-hexenol and 1-octen-3-ol are the main odorous components of the perfumes belonging to the fougère accord family. This suggests that the fougère scent from the perfumers' imagination is a natural fragrance.     

Pigment identification on "Pietà" of Barletta, example of Renaissance Apulian sculpture: a Raman microscopy study

A study of the original painting layer of the "Pietà" of Barletta, a polychrome statue, important example of Renaissance Apulian sculpture, was performed by mu-Raman spectroscopy. Vermilion was identified in the original layer of the blood drops on Jesus knee. Lazurite was identified as the original blue pigment on Our Lady's veil and lace, currently a yellow ochre-like color. The use of lazurite demonstrates the historical-artistic importance of this polychrome statue, and supports the hypothesis that this artwork was probably commissioned by Our Lady's devotees to itinerant artists inspired by the more precious Vesperbilder model.     

Quantitative determination of jatrophone in "cachaça" prepared with Jatropha elliptica

A method for sample preparation and analysis by high performance liquid chromatography with UV detection (HPLC-UV) was developed for analysis of jatrophone in "cacha?a" prepared with Jatropha elliptica, administered orally, employed in Brazil for the treatment of venomous snake bites. The linearity, accuracy, precision of the procedure was evaluated. Analytical curve for jatrophone was linear in the range of 16.24-81.20 microg ml(-1). The recovery of the jatrophone in the samples analyzed was 98.99-99.89%. The percent coefficient of variation for the quantitative analysis of the "cacha?a" in the analyses was under 2%.     

Lewis vs. Brønsted-basicities of diiron dithiolates: spectroscopic detection of the "rotated structure" and remarkable effects of ethane- vs. propanedithiolate

The new complexes Fe2(S2CnH2n)(CO)2(dppv)2 (n = 2, 3; dppv = cis-1,2-C2H2(PPh2)2) form adducts with AlBr3 and B(C6F5)3, which adopt the "rotated structure" proposed for the active site of the Fe-only hydrogenases--the propanedithiolate is significantly more Lewis basic due to nonbonded interactions between the dithiolate strap and the ligands on Fe.     

Equilibrium of Life-Elements' Periodic Rhythm and Health——The Scientific Involution of Chinese Ancient "Syncretism of Living Matter and Universe" Philosophy (Ⅰ)

旅澳学者裘凌沧教授积几十年微量元素科学研究成果,突破传统学科概念的束缚,以东方哲学为核心,运用近代系统工程学方法,分析了生命元素周期变化节律平衡与健康的关系,包括:内、外环境生命元素的特性,系统节律平衡是生命健康的基础和系统节律平衡调控的途径.本文分期刊出.     

Total Synthesis of Several 3, 3"-Biflavones

BiflavonesareamorecomPlicatedclass0fflavonoids.MostofthemareusefulcomPonentsoftraditionalmedicinetocurediseases.Sincechamaejasminel,anewtoeofbiflavonoidpossessingaC-3/C-3"linkage,wasisolatedfromSteUerachamaejasmaeL.byHuangetal',especiallyafterthebiologicalactivityofani-cancerwasdiscovered',thestUdyof3,3"-biflavonoidshasattfactCdmuchattention.3-5ButtherehasbeennoprogressmentionedonthesynthesisofthiskindofcomPoundsinrecentdecades.AsaresultofoursystematicresearchonthesynthesisofchamaejasInin…     

The Isolated System of Quantifiable Experiences in the 1783 "Mémoire sur la chaleur" of Lavoisier and Laplace

Abstract

The thesis of the present paper is that the famous memoir of Antoine-Laurent Lavoisier and Pierre Simon Laplace of 1783 inaugurated the study of a new unit of experimentation, the isolated system of quantifiable experiences. It was defined by a linear equation, ruled by a principle of thermal reversibility and realised experimentally by a calorimetric apparatus. This notion took its origins from a specific context of studies of heat and its quantification that involved the two scientists from 1777: attempts to verify the mechanisms of combustion and animal respiration. Born from an original interpretation of the principle of conservation of vires vivae, the concept of system is deeply connected with the formulation of a new way to quantify chemical reactions. This method leaves nonquantifiable entities out of consideration and is the basis of the subsequent principle of conservation of matter. This paper argues that the Lavoisierian concept of system arises from the eighteenth-century studies on heat and from an experimental approach different from that of the quantitative chemistry of the Scottish tradition. Following this new logic, the transformation of vital air into fixed air was proved to be the effect of combinations between specific basis and heat, not determined by the addition/subtraction of matter: the combustion of bodies and animal respiration could never be considered mere inflammatory processes.     

Equilibrium of Life - Elements' Periodic Rhythm and Health — The Scientific Involution of Chinese Ancient "Syncretism of Living Matter and Universe" Philosophy ( Ⅲ )

3 以"人民体质建设"为中心的系统节律平衡调控途径 3.1 "天人合一"与生命健康 以全国表土61元素分布(图略)和26个肿瘤死亡率分布(图略)分别代表"天"(外环境)和"人"(内环境),两者看似各自独立的,但从生命元素的特性出发,两者均遵循生命元素周期变化节律,所以这是"天人合一"的物质基础和核心(见图31). "天"、"人"又构成了密切联系、影响和制约的动态平衡系统和以人为中心的"生物地球化学食物链",这就是节律平衡调控的途径(见图32).     

The "dark side" of β-lactoglobulin: unedited structural features suggest unexpected functions

The in-depth characterization of water buffalo (WB) whey proteins based on chromatographic and mass spectrometric techniques revealed unexpected structural co- and post-translational modifications for β-lactoglobulin (β-Lg). The residues Lys⁴⁷ and Lys⁶⁹ of β-Lg were found to be lactosylated early, at the time of milking. Thiol groups of β-Lg underwent a dynamic sulfhydryl/disulfide exchange that is probably essential in accomplishing specific physiological requirements in which proteins may alternatively act either as a trigger or as a target. In this sense, the free sulfhydryl group of β-Lg established a glutathionylation/deglutathionylation equilibrium, which could be functional in conveying and delivering glutathione. Furthermore, the N-lauroylated β-Lg occurring exclusively in WB milk has been characterized for the first time. N-acylation could be an evolutionary remnant of ancestral lipocalins. Combined with the known aptitude of β-Lg to interact with phospholipid bilayers, this suggests that the protein could also be involved in the membrane translocation of small molecules, in addition to targeting, trafficking or the maintenance of membrane integrity. This structural characterization of β-Lg adds to the currently existing data and expands our understanding of the possible biological roles of this enigmatic protein.