Behavior of Zn,Cu, Pb and Cd in biota of Yangtze Estuary

The contents of zinc, copper, lead and cadmium were measured in the dominant species (plants:Scripus triquetor andPhrgrmites australis, macrobenthos:Ilyoplax deschampsin, Helice tridens tientsinensis, Bullacta exarata and Corbicula fluminea, and migrating waders: Calidris ruficollis and C. alpina) of the ecosystem of Yangtze Estuary, China, from 1995–1998. Results show that:

1. (1)

   Since the heavy metals stored in plants during growth seasons will be released into the environment in winter, plants are temporary stocks for metals. For the aboveground parts of reeds, about 156.6 kg·ha^-1·a^-1 of zinc, 369.9 kg·ha^-1·a^-10 of copper, 32.9 kg·ha^-·a^-1 of lead and 6.5 kg·ha^-1·a^-1 of cadmium were released.

2. (2)

   The mollusca, especially C.fluminea, are the key species storing and transporting heavy metals on the food chain.

3. (3)

   The temporal change in the highest trophic level was studied and found that it was significantly related with metabolic rates. The contents of heavy metals in Dunlin reach the peaks in January and October, which are wintering season and migratory season, respectively, of the bird.

4. (4)

   Organisms often show regulation/accumulation mechanisms to different elements of heavy metals. The elements that are widely required, such as zinc and copper, are accumulated at the metabolically active parts. It is quite another thing for the other two elements. Lead was regulated well and scarcely accumulated in the bodies of macrobenthos, but cadmium was absolutely accumulated in the animals.

5. (5)

   Heavy metals were found accumulated in some parts of the bodies of these organisms, such as shells and skeletons of macrobenthos and lives and muscles of waders.

6. (6)

   All these four elements were accumulated higher in the bodies of waders than in the plants and macrobenthos, which showed a bio-magnification function of the food chain. Overall, besides the physical and chemical processes, biological processes of heavy metal elements in Yangtze Estuarine ecosystem play a very important role in self-purification function of the ecosystem. Measurement of heavy metal contents in plants and animals in the estuarine ecosystem is an efficient technology for monitoring the environmental quality of the estuary.

     

Initial quantum levels of captured muons in CO,CO2, and COS

The role of valence electrons for the muon capture process by molecules is experimentally investigated with the aid of cascade calculations. Low-momentum muons are introduced to gas targets of CO, CO₂, and COS below atmospheric pressure. The initial states of captured muons are determined from the measured muonic X-ray structure of the Lyman and Balmer series. We propose that the lone pair electrons in the carbon atom of CO significantly contribute to the capture of a muon with large angular momenta.

     

Behaviour of the Different Oxydation States of As,Sb, Se and Sn Using Dithiocarbamates for Their Separation from Environmental,Food and Drug Samp1es

The mentioned elements are known to occur in the environment in different oxydation states with different biological activities.

Speciation of the oxydation state by selective enrichment can lead to relevant information for the toxicologist.

-allows to discriminate between the oxidation states of the mentioned elements

-converts the elements to the optimum oxydation state for enrichment from the sample

-brings the elements in an ideal form for their determination by x-ray fluorescence analysis using coprecipitation with the dibenzyl-ammoniumsalt of dibenzyldithiocarbamic acid.

An outline of the method, instrumentation used and applications to organic, biological and environmental samples is given.     

Selection,Characterization, and Biodegradation of Surgical Epoxies

A series of epoxy resins has been formulated on the basis of obtaining low water sorption, low water vapor permeability, retention of electrical properties, and resistance to biodegradation by the body. These resins have been tested for these properties both by accelerated aging in 100°C water and in vivo studies.

A literature survey was conducted on the biodegradation of surgical plastics with the findings that nylon lost 80% of its tensile strength after 3 years implantation while Orlon and Dacron deteriorated considerably less in a 2-year period. Teflon, Mastic, and Mylar showed almost no loss in tensile strength after 17 to 22 months.

The epoxies tested on this program showed no loss in strength after 6 months in vivo.

It appears that materials whose chemical structure contain bonds similar to those found in the body (such as amide groups) are susceptible to biodegradation whereas those such as Teflon which contain only C-C bonds or C-F bonds are not.

Two general types of biodegradation can occur on polymers: Attack starting at the end of a polymer chain and proceeding along the chain to produce monomeric fragments (as in polypropylene), and attack at regular intervals along a polymer chain where susceptible cross-linking groups are present to produce macromolecular fragments.

It has been postulated that attack on polymers takes place in the amorphous areas (if they are present) to leave the more crystalline areas of the material intact. Thus, with implantation, these types of materials become brittle.

Histology on the developed epoxies indicated that epoxies containing nonreactive hydrophobic diluents showed a greater foreign body reaction than normal epoxies without such diluents.     

A Study on the Preparation,Structure, and Properties of Microcrystalline Cellulose

Abstract

The preparation, structure, and properties of microcrystalline cellulose (MCC) from rice straw were investigated by IR, x-ray, viscometry, polarizing microscope, SEM, etc. The results are as follows:

1. The leveling-off degree of polymerization (LODP) obtained from rice straw is about 80–150. The dimensions of MCC granules are 20–30 μm length, 0.5–0.8 μm thick, and the crystallinity is about 80%.

2. The aqueous suspension of a certain concentration of MCC can form a gel under the effect of shear force. The viscosity of MCC gel increased with an increasing content of MCC in water. A sharper increase of viscosity occurred in the 3–6% range.

3. The addition of one or two valence salts into the MCC gel increased the viscosity.

4. The viscosity of MCC gel has its maximum value at pH 8.

5. The MCC gel as an emulsifying agent can form a stable emulsion in the oil/water system when the ratio of oil/water is below 6/4.     

Development,Characterization and Application of Predictive-Toxicology Models

Abstract

The adoption of SAR techniques for risk assessment purposes requires that the predictive performance of models be characterized and optimized. The development of such methods with respect to CASE/MULTICASE are described. Moreover the effects of size, informational content, ratio of actives/inactives in the model on predictivity must be determined.

Characterized models can provide mechanistic insights: nature of toxicophore, reactivity, receptor binding. Comparison of toxicophores among SAR models allows a determination of mechanistic overlaps (e.g., mutagenicity, toxicity, inhibition of gap junctional intercellular communication vs. carcinogenicity).

Methods have been developed to combine SAR submodels and thereby improve predictive performance.

Now that predictive toxicology methods are gaining acceptance, the development of Good Laboratory Practices is a further priority, as is the development of graduate programs in Computational Toxicology to adequately train the needed professional.     

A review of: “Particle-Size Distribution II: Assessment and Characterization (ACS Symposium Series 472; Provder,T”, Ed.; American Chemical Society: Washington, 1991. pp. xiii+407 $89.95.

ABSTRACT

An automated set-up is described which permits the fast determination of the composition limits of isotropic microemulsion phases of ternary (water/oil/surfactant) systems. It is especially well suited for the investigation of systems including nonionic surfactants, which are very sensitive to temperature changes.

Four systems have been tested including hydrogenated as well as fluorinated surfactants and oils. Both direct and inverse microemulsion phases have been chosen for these investigations.

The results obtained and their comparison with previously reported diagrams are used to draw some general conclusions concerning the advantages and limits of an automatic procedure. It appears that the recordings obtained with such procedures are particularly easy to interpret for certain types of systems for which very neat turbidity changes are observed (case of reverse fluorinated systems for instance). For other systems (those for which there exists a liquid-crystalline phase for instance) care must be taken when interpreting the turbidity vs temperature curve.

The method is particularly useful when dealing with expensive products for which one cannot afford to prepare a sealed ampoule for each point of interest in the phase diagram.     

Beiträge zur Chemie der Pyrrolpigmente, 14. Mitt. Interkonversionsprozesse bei Arylmethylidenpyrrolinonen; ein Spezialfall atropisomerer,sterisch gehinderter Styrole

Starting from a chiral substituted benzaldehyde diastereomeric arylmethylidenepyrrolinones were accessible. The geometrical structures of the corresponding isomers were investigated by lanthanide ion induced shift technique and UV spectroscopy. By equilibration studies, D-NMR measurements and kinetic data a complete picture of the various ground state enthalpy differences as well as the activation energies of the transition paths was gained.The results are in accord with the barriers determined for two simple model derivatives belonging to the class of atropisomeric sterically hindered styrenes.

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Mit 2 Abbildungen

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Herrn Prof. Dr.H. Nowotny mit den besten Wünschen zum 65. Geburtstag gewidmet.

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13. Mitt.:H. Falk, K. Grubmayr, O. Hofer, F. Neufingerl undJ. M. Ribó, Mh. Chem.107, 831 (1976).     

Rice Husk Ash: A New,Cheap, Efficient,and Reusable Reagent for the Protection of Alcohols,Phenols, Amines,and Thiols

Abstract

A mild, efficient, and eco-friendly protocol for the protection of alcohols and phenols as trimethylsilyl ethers has been developed using rice husk ash as a reagent. This reagent is also able to catalyze the acetylation of alcohols, phenols, thiols, and amines with acetic anhydride. All reactions were performed under mild conditions in good to high yields.

[Supplementary materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements for the following free supplemental files: Additional text, tables, and figures.]     

Influence of feedstock source on biocatalyst stability and behavior,and on reactor performance,in continuous intensified ethanol fermentation

An ethanol process based on a gas-lift tower fermenter arrangement was used as a model system to show the strong dependence of reactor behavior on the developing chemical environment within the reactor. The reactor performance limits for realistic substrates—starch and molasses—are characterized and compared with those attainable on an ideal substrate, glucose.

     

Ultra-trace Analysis of Metosulam,a New Triazolopyrimidine Herbicide,in Soil Using LC-UV and TSP-LC-MS

Abstract

Metosulam (DE-511), N-(2,6-dichloro-m-tolyl)-5,7-dimethoxy-[1,2,4] triazolo [1,5a]pynmidine-2-sulphonamide is a new selective herbicide developed for the control of broadleaf weeds in cereals and maize.

The application of new generation low use rate herbicides, such as metosulam, has in turn created the need for the development of ultra-trace residue methodologies. To help investigate the environmental impact of metosulam, levels at sub-part per billion (μg/kg) in soil were determined.

Application of capillary gas chromatography, with various injector systems, was unable to analyse metosulam methyl derivative due to the inherent thermal instability of the molecule. Liquid chromatography with ultraviolet detection (LC-UV) was used to quantify residues of the herbicide following a series of selective clean-up procedures. The chosen methodology used simple reagents plus standard equipment and although the molar absorbtivity of metosulam is poor, analysis of soils of various texture classes at the desired sensitivity level, was achieved.

Thermospray Liquid chromatography with mass spectrometry (TSP-LC-MS) was used as a confirmatory technique for the analysis of metosulam in the same soils. Excellent agreement between the two techniques was observed.

Details of the clean-up procedures used to produce desired selectivity and the relative merit of the two detection systems are discussed.     

The Oxidation of Guaiacol,Serotonin, o-Cresol,p-Cresol,m-Cresol,Homovanillic Acid,and m-Tyrosine by Horseradish Peroxidase and Hydrogen Peroxide

Abstract

A survey of 14 substrates for the fluorometric determination of the oxidative enzyme-horseradish peroxidase was carried out. The compounds which seemed to act well as substrates are serotonin, guaiacol, o-cresol, p-cresol, m-cresol, homovanillic acid and m-tyrosine. L-Epinephrine, equilenin, equilin, β-estradiol, estriol, and estrone were studied and found not to be substrates of the system.

The kinetics of the oxidation reactions were studied. They followed the Michaelis constant rate equation. The Michaelis constant, Km, was determined by a Lineweaver-Burk plot for each substrate.

It would appear that the presence of a group in the ortho, para, or meta position of the phenolic ring decreases the binding of the subtrate to the enzyme's active site, as shown by the km values obtained. It may be concluded that m-tyrosine is the best substrate (lowest km value) when compared to all the substrates which have been studied to date by the authors.     

Anthracene-Derived Bis-Aminophosphonates: Crystal Structure,In Vitro Antitumor Activity,and Genotoxicity In Vivo

Abstract

The X-ray crystal structures of the anthracene-derived bis-aminophosphonates 4.4′-bis[N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]diaminodiphenylmethane (1) and 1,3-bis

[N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]diaminobenzene (3) are reported. The X-ray analyses demonstrated that both compounds crystallize in a centrosymmetric manner containing a meso-form (1) and a pair of enantiomers (3).

The cytotoxic potential, genotoxicity, and antiproliferative activity of bis-aminophosphonates 1 and bis[N-methyl(diethoxyphosphonyl)-1-(9-anthryl)]benzidine (2), as well as their subcellular distribution in a tumor cell culture system, are also discussed. Compounds 1 and 2 showed optimal antiproliferative activity to human tumor cells from colon carcinoma line HT-29. In vitro and in vivo safety testing revealed that the compounds exert lower toxicity to normal cells as compared with well-known anticancer and cytotoxic agents.

Supplemental materials are available for this article. Go to the publisher's online edition ofPhosphorus, Sulfur, and Silicon and the Related Elementsto view the free supplemental file.     

RETRACTED ARTICLE: Four Ln-coordination polymers: synthesis,crystal structure,fluorescent sensing of nitrobenzene and Tb3+, and catalytic properties

We, the Editors and Publisher of Journal of Coordination Chemistry, have retracted the following article:

Yu-Yuan Tang, Shuang Chen, Cui-Juan Wang, Zi-Xin Zhu & Dong-Ning Liu. Four Ln-coordination polymers: synthesis, crystal structure, fluorescent sensing of nitrobenzene and Tb³⁺, and catalytic properties. Journal of Coordination Chemistry 71.19 (2018) 3207-3221. DOI: 10.1080/00958972.2018.1517257

Since publication it has come to our attention that there are duplications of data for the europium compound (compound 1) presented in the above 2018 article and the terbium compound presented in the below 2017 article.

Yu-Yuan Tang, Cui-Juan Wang, Shuang Chen & Hai-Yu Dai. A terbium(III) organic framework as a fluorescent probe for selectively sensing of organic small molecules and metal ions especially nitrobenzene and Fe³⁺. Journal of Coordination Chemistry 70.24 (2017) 3996-4007. DOI:10.1080/00958972.2017.1413490

The cell constants presented in the two papers for the two different compounds are identical, including the esds for the lengths of the axes and the absence of esds on the bond angles. Examination of the submitted CIFs for the two compounds showed identical information plus additional data, including the crystal dimensions. The deposited hkl files for the two different compounds are identical, indicating that the same crystal data was used for the two compounds.

Following COPE guidelines, Taylor & Francis has contacted the authors as well as their affiliated institution with a request for clarification, however the explanation we received has not been satisfactory. As such, we are retracting both papers as it is clear data has been duplicated between the two structures. The authors were informed of this decision and have since agreed to the retraction.

We have been informed in our decision-making by our policy on publishing ethics and integrity and the COPE guidelines on retractions.

The retracted articles will remain online to maintain the scholarly record, but they will be digitally watermarked on each page as “Retracted”.     

Copolymerization of Maleic Anhydride with Benzofuran,Indole, and Benzothiophene

Abstract

Maieic anhydride (MAn) forms alternating copolymers with benzofuran (BF), indole, and benzothiophene (BT) under the influence of azobisisoburyronitrile. In all three cases the yield and molecular weight were highest when equimolar amounts of both monomers were used. The association constants of charge-transfer complex formation of MAn with the three comonomers have been measured at various temperatures by NMR. The following values were obtained (at 20°C):

MAn-BF ca. 0.01 liter/mole (in cyclohexanone)

MAn-indole 0.28 liter/mole (in chloroform)

MAn-BT 0.30 liter/mole (in chloroform)

The results indicate that the reactivity of the comonomers to form copolymers with MAn is governed by the resonance stabilization of the monomer and to a lesser extent by complex formation. The rate of copolymerization is much higher for the MAn-BF system than for the two other systems. In the former case it is not necessary to invoke charge-complex formation to explain the copolymerization.     

Synthesis and Ldasic Properties of O,O,O-Triethyl-N-(2-Pyridyl) Imidophosphates

Abstract

The phosphorus (111) compounds are known to react readily with arylazides resulting in the formation of imi-dophosphorus compounds (Staudinger reaction)¹.

We nave obtained O,O,O-triethyl-Ii-(2-pyridyl)imido-pnosphates by the reaction of triethylphosphites with 2-pyridylazides (existing as tetrazoles) with a good yield.     

Ethanol,the ultimate feedstock

Ethanol appears to be a key factor in the “biomass alternative” to fossil feedstocks for producing fuels and chemicals. If produced at a low enough price relative to crude oil, it and its derivates could account for 159 billion pounds, or 50%, of the US production of synthetic organic chemicals, presently valued at $113 billion. This use would consume 4.2 billion bushels, or about 54%, of the corn crop.

This study evaluated the potential savings in ethanol manufacture to be gained by applying advanced process engineering or genetic engineering of improved organisms, centering on the use of fluidized bed bioreactors operating at high cell densities with immobilized cells of either the Saccharomyces yeast or the bacterium: Zymomonas mobilis.

A new continuous plant could produce at about $1.82/gal based on Zymomonas or $1.97/gal based on the Saccharomyces yeast. The bacterium has a competitive edge as a result of its lower sensitivity to product inhibition.

There appears to be no inherent design limitation to effect the engineering improvements required for the advanced process. In a longer-term, more difficult research effort, it might be possible to reduce or eliminate product inhibition to reduce cost even further.

     

Design,Synthesis, and Anticancer Activity of Amide Derivatives of Structurally Modified Combretastatin-A4

A new series of amide derivatives of structurally modified combretastatin-A4 10a–10j are synthesized, and their structures are confirmed by ¹H and ¹³C NMR, and mass spectral data. The products are tested for their anticancer activity towards human cancer cell lines, MCF-7 (breast), A-549 (lung), Colo-205 (colon), and A-2780 (ovarian). The compounds 10b, 10c, and 10d demonstrate the most promising activity.

     

Simultaneous Determination of Lonidamine, 1-(2,4-Dichlorobenzyl)-1h-indazole-3-carboxylic Acid,a New Antitumoral,and Its Impurity,N2 Substituted Isomer,by UV Derivative Spectrophotometry

Abstract

A direct and fast analytical method for the determination of Lonidamine and its impurity of synthesis, the N₂ alkylated isomer, by UV derivative spectrophotometry, is described.

The procedure was defined by regression analysis for a high number of standard solutions.

Linear relationships were obtained between mixture composition and maximum amplitude in <²D at 316 nm for Lonidamine quantitation, and peak trough ⁴D 226,234 and ⁴D 323,316 amplitudes by utilising polynomial equation for N₂ isomer quantitation.

The method, yielding accurate and precise results, was satisfactorily applied to laboratory mixtures and to a commercial formulation.     

Design,Synthesis, Antimicrobial,and Antioxidant Activity of Dimers of Chromene Containing 1,2,3-Triazole Derivatives Bearing an Alkyl Spacer

A new series of chromene based 1,2,3-triazole derivatives has been synthesized by incorporating biologically active heterocyclic rings containing chromene and triazole moieties in one molecular structure. All newly synthesized compounds are characterized by ¹H and ¹³C NMR, mass, and IR spectra. The title compounds are tested for their activity against different bacterial and fungal strains, and antioxidant activity. Several compounds are determined to be potent antimicrobial and antioxidant agents.