Advances in properties and biodegradability of co-continuous,immicisible, biodegradable,polymer blends

A series of blends consisting of polylactic acid (PLA) and aliphatic succinate polyester (Bionolle#3000) have been prepared. The results of the mechanical property investigation have shown that using more than 20 wt % Bionolle#3000 can significantly increase the toughness of the PLA, increase the elongation at break (more than 200%) and increase the impact strength (more than 70 J/m). These properties were not significantly affected by the aging behavior of PLA for more than two months. DMA results show that Bio#3000 reduces the elastic modulus of the blends between −15°C and 60°C. Soil degradation rates of the PLA/Bio#3000 blends also increase with increasing Bio#3000 content. However, for the blends with less than 30 wt % of Bio#3000, the degradation rates do not significantly increase. Enzymatic degradation rates of the blends are higher than for those of the two polymers, and these rates increase with increasing PLA content. Composting biodegradation rates increase with increasing Bio#3000 content.     

Acetal,triphenyl phosphorane,enol ether,acidic hydrolysis,nitroxyl

Two acetals were synthesised with hydroxymethyl triphenylphosphonium chloride as the alcoholic component. Reaction with ketones in the Wittig synthesis yielded enol ethers which were hydrolysed to aldehydes under acid catalysis. Tetrahydropyranyloxy compounds could be hydrolysed under milder conditions whereas, methoxymethyl ethers needed slightly more drastic conditions than the methyl ethers normally used in this synthesis.     

Transport coefficients of argon,nitrogen, oxygen,argon-nitrogen,and argon-oxygen plasmas

Calculated values of the viscosity, thermal conductivity, and electrical conductivity of argon, nitrogen, and oxygen plasmas, and mixtures of argon anti nitrogen and of argon anti oxygen, are presented. In addition, combined ordinary, pressure, and thermal diffusion coefficients are given for the gas mixtures. These three combined diffusion coefficients fully describe di fusion of the two gases, irrespective of their degree of dissociation or ionizati on. The calculations, which assume local thermodynamic equilibrium, are performed! for atmospheric-pressure plasmas in the temperature range /torn 300 to 30,000 K. A number of the collision integrals used in calculating the transport coefficients are significantly more accurate than values used in previous theoretical studies, resulting in more reliable values of the transport coefficients. The results are compared with those of published theoretical and experimental studies.     

ChemInform Abstract: X2Y2 Isomers: Tuning Structure and Relative Stability Through Electronegativity Differences (X: H,Li, Na,F, Cl,Br, I; Y: O,S, Se,Te).

Density functional calculations on XYYX and X₂YY isomers of the X₂Y₂ species (X: H, Li, Na, F, Cl, Br, I; Y: O, S, Se, Te) show that the XYYX isomers are more stable than the X₂YY forms except for X = F and Y = S and Te, for which the F₂SS and F₂TeTe isomers are slightly more stable.     

Hairs,criminals, moonrocks,metals diseases,polluters! Where next for nuclear analytical chemistry?

Nuclear methods of analysis have advanced dramatically in recent years, and in many ways, techniques that once were viewed as a scientific curiosity and the toys of a few scientists working in large nuclear research establishments, are now semi-routine and can be applied even by young students. Large amounts of good analytical data are outputted from instruments having sophisticated embedded software. It is interesting to speculate on the directions that nuclear analytical techniques may take next: whether more multielement; more automation for vastly larger sample suites; extension to minor and major components of samples as well as trace components; coupling of nuclear methods to hyphenated methods. However, in some respects the resources needed to continue to develop and apply radioanalytical methods are on the wane: reactors and accelerators are being closed and fewer radiochemical specialists are being trained. The open question, is whether instrumental analysis techniques will offer more and better results with less effort, or be less equipment intensive? In this paper some personal reflections on nuclear actcivation methods and their trends are presented and discussed. Some mileposts in the development of the field and some unique and interesting applications (as implied by the paper title) are cited and discussed.     

Separations involving palladium: Separation of lead,bismuth, cadmium,thallium, copper,cobalt and nickel from palladium

It has been shown that 1% dimethylglyoxime solution in alcohol can be efficiently used to separate quantitatively palladium from other metals of the copper group, as indicated in the new and more comprehensive scheme of qualitative analysis.     

Highly activated, silicone entrapped, lipase

Lipase is more reactive in silicone oil or silicone elastomers than in hydrocarbons, and can be formulated into convenient, active, immobilized enzyme packages.     

Aromatically functionalized cyclic tricholate macrocycles: aggregation, transmembrane pore formation, flexibility, and cooperativity

The aggregation of macrocyclic oligocholates with introverted hydrophilic groups and aromatic side chains was studied by fluorescence spectroscopy and liposome leakage assays. Comparison between the solution and the membrane phase afforded insight into the solvophobically driven aggregation. The macrocycles stacked over one another in lipid membranes to form transmembrane nanopores, driven by a strong tendency of the water molecules in the interior of the amphiphilic macrocycles to aggregate in a nonpolar environment. The aromatic side chains provided spectroscopic signatures for stacking, as well as additional driving force for the aggregation. Smaller, more rigid macrocycles stacked better than larger, more flexible ones because the cholate building blocks in the latter could rotate outward and diminish the conformation needed for the water-templated hydrophobic stacking. The acceptor-acceptor interactions among naphthalenediimide (NDI) groups were more effective than the pyrene-NDI donor-acceptor interactions in promoting the transmembrane pore formation of the oligocholate macrocycles.     

The determination of aluminum,nickel, cobalt,copper, and iron in alnico

A method has been developed for the determination of the major constituents of Alnico based on an anion exchange separation of the chloride complexes and the subsequent determination of aluminum, nickel, copper, cobalt and iron with EDTA. The method is more convenient than conventional classical methods.     

Pathways to folding, nucleation events, and native geometry

We perform extensive Monte Carlo simulations of a lattice model and the Gō potential [N. Gō and H. Taketomi, Proc. Natl. Acad. Sci. U.S.A. 75, 559563 (1978)] to investigate the existence of folding pathways at the level of contact cluster formation for two native structures with markedly different geometries. Our analysis of folding pathways revealed a common underlying folding mechanism, based on nucleation phenomena, for both protein models. However, folding to the more complex geometry (i.e., that with more nonlocal contacts) is driven by a folding nucleus whose geometric traits more closely resemble those of the native fold. For this geometry folding is clearly a more cooperative process.     

Transport coefficients of air,argon-air,nitrogen-air,and oxygen-air plasmas

Calculated values of the viscosity, thermal conductivity and electrical conductivity of air and mixtures of air and argon, air and nitrogen, and air and oxygen at high temperatures are presented. In addition, combined ordinary, pressure, and thermal diffusion coefficients are given for the gas mixtures. The calculations, which assione local thermodynamic equilibrium, are performed for atmospheric pressure plasmas in the temperature range from 300 to 30,000 K. The results for air plasmas are compared with those of published theoretical and experimental studies. Significant discrepancies are found with the other theoretical studies; these are attributed to differences in the collision integrals used in calculating the transport coefficients. A number of the collision integrals used here are significantly more accurate than values used previously, resulting in more reliable values of the transport coefficients.     

Low-lying electronic states and dissociation energies of the monochlorides of Cr, Mn, Fe, Co, and Ni

Published equilibrium data involving the gaseous monochlorides of Cr, Mn, Fe, Co, and Ni have been re-examined by thermochemical analysis, using more recent information on the low-lying electronic states, yielding D degrees 0 values in kcal mol-1 of CrCl (90.0), MnCl (79.8), FeCl (79.3), CoCl (81.3), and NiCl (88.1). Although this revised approach is believed to yield more reliable values of the FeCl, CoCl, and NiCl dissociation energies, results show that use of M+ electronic levels in place of the adopted MCl values leads to alternate D degrees 0(MCl) values agreeing within 1.6 kcal mol-1, providing a useful check on electronic-level contributions to the thermochemical calculations.     

PHOTOBIOLOGICAL PROPERTIES OF A NOVEL, NATURALLY OCCURRING FUROISOCOUMARIN, CORIANDRIN

The photobiological properties of a novel, naturally occurring furoisocoumarin isolated from coriander and named coriandrin are described. Photosensitized lethal and mutagenic effects in bacteria indicate that it is more active than psoralen. It is a weak frameshift mutagen in the dark. Mammalian cells in tissue culture are photosensitized more actively with coriandrin than with psoralen even though preliminary evidence from interrupted radiation experiments and DNA analysis suggest that coriandrin does not form DNA interstrand crosslinks. Sister chromatid exchanges were induced with a unit dose of 1.1 x 10(-2) with coriandrin; the value for psoralen is 3 x 10(-3). Coriandrin appears to be metabolized more rapidly than furocoumarins by liver mixed function oxidases. Skin photosensitizing activity is very weak compared with psoralen, a surprising observation considering its potency in biological test systems.     

Pyrylium,pyridine, and N-phenylpyridinium derivatives of cyclopentadienyltricarbonylmanganese

2,4,6-Trisubstituted pyrylium salts containing a cymantrenyl substituent in the 6 position were synthesized by condensation of acetylcymantrene with chalcones. As compared with the corresponding pyrylium derivatives of ferrocene, the pyrylium salts obtained exchange a heteroatom more readily and are more stable. The pyrylium derivatives of cymantrene were converted to the corresponding pyridines by the action of ammonium acetate in glacial acetic acid or an aqueous solution of ammonia and to the corresponding N-phenylpyridinium salts by the action of aniline in acetic acid or alcohol.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 21–24, January, 1979.     

Artificial Antiferromagnets Possessing Extended Zero-, One-, Two-, and Three-Dimensional Structures

Layered (2D) artificial (or synthetic) antiferromagnets are fabricated by atom deposition techniques and possess very thin, nanometer-scale, magnetically ordered layers separated by a very thin nonmagnetic layer that antiferromagnetically couples the magnetic layers. Artificial antiferromagnets were crucial in the discovery of the giant magnetic effect (GMR), which had an incredible impact on the evolution of computer memory and its applications, and nucleated the dawn of spintronics (magnetoelectrics). The fundamental structural motif has been more recently achieved by using synthetic chemical methods that led to insulating artificial antiferromagnets. Examples of magnetically ordered layers that are antiferromagnetic coupled to form artificial antiferromagnets have been extended to isolated ions (0D) as well as extended chain (1D) and extended network 3D structures, and new phenomena and applications are anticipated as insulating antiferromagnets are more effective at propagating spin currents with respect to dielectric materials.     

Galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, five new antioxidative glycosides, and suffruticoside E, A paeonol glycoside, from Chinese moutan cortex.

Five new antioxidative glycosides named galloyl-oxypaeoniflorin, suffruticosides A, B, C, and D, and a new paeonol glycoside named suffruticoside E have been isolated from Chinese Moutan Cortex, the root cortex of Paeonia suffruticosa ANDREWS, together with antioxidative galloyl-paeoniflorin. Their structures were elucidated on the basis of chemical and physicochemical evidences. Galloyl-oxypaeoniflorin, galloyl-paeoniflorin, suffruticosides A, B, C, and D showed more potent radical scavenging and antioxidative effects than alpha-tocopherol.     

Microwave-assisted green synthesis of anilines,phenols, and benzenediamines without transition metals,ligands, or organic solvents

A novel, microwave-assisted method producing anilines and phenols from activated aryl halides is reported. This high-yielding method reduces current reaction requirements and removes organic solvents and catalysts making a more efficient and eco-friendly alternative for the synthesis of important pharmaceutical building blocks.     

Problems of Economic Exploitation of Basic Research Findings (Discoveries,Inventions, Patents,Licenses)

In spite of high expenditures for basic research and its indisputable significance for technological development, the knowledge so gained seldom finds its way into industrial practice without difficulty and undue delay. Even without changing the aims of basic research, more commercially exploitable research results will be obtained in the future. It is in the interests of the public and the scientists themselves that such results, not only broaden scientific knowledge, but also be transferred in the best possible way into innovative practice. An intensified patent and license policy for scientists inventions is a more appropriate solution to this effect than any independent legal protection for scientific discoveries.     

Lipophilicity in PK design: methyl, ethyl, futile

Lipophilicity, often expressed as distribution coefficients (log D) in octanol/water, is an important physicochemical parameter influencing processes such as oral absorption, brain uptake and various pharmacokinetic (PK) properties. Increasing log D values increases oral absorption, plasma protein binding and volume of distribution. However, more lipophilic compounds also become more vulnerable to P450 metabolism, leading to higher clearance. Molecular size and hydrogen bonding capacity are two other properties often considered as important for membrane permeation and pharmacokinetics. Interrelationships among these physicochemical properties are discussed. Increasing size (molecular weight) often gives higher potency, but inevitably also leads to either higher lipophilicity, and hence poorer dissolution/solubility, or to more hydrogen bonding capacity, which limits oral absorption. Differences in optimal properties between gastrointestinal absorption and uptake into the brain are addressed. Special attention is given to the desired lipophilicity of CNS drugs. In examples using -blockers, Ca channel antagonists and peptidic renin inhibitors we will demonstrate how potency and pharmacokinetic properties need to be balanced.