bluuebunny/crossref_metadata_2025 huggingface dataset:
Palaeoecology: Methods
Authors: Terry Rebecca C
Published: December 2009

Paleoecology is based on the documentation of occurrences and abundances of taxa across time and space. Although methodologically similar to the techniques of neontological ecologists, the discipline is distinct in its integration of a deeper time axis into our understanding of the processes shaping the earth's ecological patterns. Taphonomy is the study of the processes by which organic remains become incorporated into the fossil record. Since this record is both incomplete and biased, multiple taphonomic approaches have been developed to quantify the reliability of the ecological information it preserves. As such, a fundamental issue in paleoecology relates to the sampling and counting of individuals. Although the nature of the preserving sediments often exerts the primary control on how data are collected, techniques exist to standardize sampling and counting strategies to maximize our ability to detect ecological patterns and gain insight into the processes shaping both ancient and modern communities.

Key Concepts:

Paleoecologists study ancient organisms and ecosystem dynamics over evolutionary time scales.

Taphonomic studies have shown that the quality of ecological information preserved in the fossil record is high.

The preservation potential of organic remains is a function of depositional environment as well as structural, chemical and behavioural characteristics of an organism.

Sample standardization is an important consideration for paleoecological data collection and analysis.

Biography information: Rebecca C Terry is a paleoecologist and taphonomist with a research focus on small mammal community dynamics through the Holocene.
ELSI
Research Programme of the
NHGRI
Authors: McEwen Jean E , Thomson Elizabeth J , Boyer Joy T
Published: December 2009

The Ethical, Legal and Social Implications (ELSI) research programme of the National Human Genome Research Institute (NHGRI) of the National Institutes of Health (NIH) is a grant programme that supports research designed to anticipate and address the implications of human genetics and genomics research for individuals, families, communities and society. Programme staff and the researchers the programme supports are involved in the bioethics components of major genomics research projects and in many activities that inform genomics‐related research, health and social policies. The programme operates collaboratively with the genomics research community, and in general, the supported research has brought greater depth and strength to the genomics research enterprise. The ELSI programme is a unique experiment in the annals of NIH‐funded biomedical research, and initial results indicate that the experiment has been successful.

Key concepts:

The Ethical, Legal and Social Implications (ELSI) research programme, within the Division of Extramural Research at the National Human Genome Research Institute of the National Institutes of Health, supports research designed to anticipate and address the implications of human genetic and genomic research, technologies and information.

The ELSI programme is currently the largest governmental supporter of bioethics research in the world.

Most ELSI research is investigator‐initiated, but the programme periodically issues requests for applications (RFAs) to solicit research targeted at particular high‐priority areas.

Neither genomics researchers nor administrators responsible for the oversight of genomics research have controlled the content or direction of ELSI research.

The research priorities of the ELSI programme have evolved and span a range of issues relating to the implications of genomics for individuals, families, communities and the broader society.

ELSI research aims to be anticipatory by encouraging researchers to identify issues likely to be raised by advances in genetics and genomics research before they arise.

ELSI research involves researchers from a wide range of disciplines and is often highly transdisciplinary.

The involvement of ELSI programme staff and ELSI researchers in major genomics research projects makes it possible to marshal the findings of relevant ELSI studies directly to inform the design and conduct of genomics research.

ELSI research has had a considerable impact on both health care and broader social policies.
Genetic Counselling Services: Outcomes
Authors: Skirton Heather
Published: December 2009

Outcome studies of genetic services have been undertaken for several decades, but defining outcomes measures that are relevant to this type of service has been challenging. Measures have included client retention of information (including the risk assessment), reproductive behaviour, psychological change and satisfaction. However, some of these outcomes, such as reproductive behaviour are inappropriate for assessment of a genetic service, and others, such as retention of recurrence risk information, appear to be less relevant to the client than to professionals. Resolution of uncertainty and changes in perception of personal control have been highlighted as aspects of the process of genetic counselling that significantly influence the outcome for the client. However, some studies have highlighted a potentially serious mismatch between the client's agenda and that of the service provider. There is a need for further collaborative work with clients to ensure that outcomes that are relevant and measurable are developed.

Key concepts:

Health services should be assessed to enable improvements to be made and to ensure that provision of the service is effective and that they meet the needs of service users.

Clinical genetic services should be assessed using relevant outcome measures.

The service user's retention of recurrence risk information has been used as an outcome measure, but may not be as important to service users as to professionals.

Change in reproductive behaviour is not a viable outcome measure for clinical genetic services.

Patient satisfaction surveys are not sufficient in themselves as outcome measures, but may contribute to the overall assessment of services.

Service users report changes in their psychological state, such as ‘peace of mind’, as a benefit of using genetic services.

Psychological change in the client is relevant as an outcome measure, but finding appropriate psychometric tools to assess these changes is challenging.

There is evidence that there may be a mismatch between what service users require and what professionals provide.

Development of usable outcome measures for genetic services requires input from all relevant stakeholders.

Further work is still required to develop suitable outcome measure tools for genetic services.
Metacommunities: Spatial Community Ecology
Authors: Gonzalez Andrew
Published: December 2009

Ecology explains the distribution and abundance of species from small to large spatial scales. Explanations based only on processes operating at local scales do not fully account for patterns of diversity at regional scales. Recent decades have seen the unification of local and regional processes as explanations for the maintenance of diversity within the metacommunity concept. A metacommunity is a set of local communities connected by dispersal of multiple potentially interacting species. Metacommunity ecology studies the interactions among species as they occur across a network of patches. The rate and frequency of dispersal mediates the spatial distribution of diversity, abundance and the flux of energy across the metacommunity. The metacommunity concept also provides a deeper understanding of the causes and consequences of species loss, and suggests solutions to mitigate these effects.

Key concepts

Concept: Summary

Colonization: A spatial process in which a population becomes established in an area where it was previously absent.

Open community: A community that experiences immigration and emigration.

Metacommunity dynamics: The dynamics of species abundances and distribution within a metacommunity due to the compound effects of species interactions and dispersal.

Local versus regional processes: Local processes occur within a community and include density‐dependent growth and interspecific interactions, whereas regional processes occur across communities and include dispersal.

Source–sink system: A network of patches of a single species connected by dispersal containing two categories of population types: (1) source populations, in which the birth rate exceeds the death rate and emigration is common and (2) sink populations, in which the death rate exceeds the birth rate and frequent immigration is required to sustain the presence of individuals.

Rescue effect: A spatial process in which local extinction is prevented by immigration from other patches in the metacommunity. The rate of immigration per patch increases as the proportion of patches occupied increases.

Neutral model: All species are assumed to be identical with respect to their birth and death rates (fitness). Stabilizing mechanisms are absent, and the abundances of all species drift randomly to extinction. Diversity is maintained in the long‐term by speciation.

Extinction debt: The delayed loss of species that occurs long after the initial loss of habitat connectivity.

Spatial insurance hypothesis: The dispersal‐dependent maintenance of biodiversity and ecosystem processes within a metacommunity.
Dismantling the Apoptotic Cell
Authors: Deming Paula , Kornbluth Sally
Published: December 2009

Apoptosis is a programme of cell death that results in dramatic morphological and biochemical changes in the dying cell due to the systematic dismantling of cellular architecture and functional pathways. The proteins that execute the apoptotic programme are a group of proteases termed caspases (
cysteine‐dependent aspartate‐specific protease
). Caspases proteolytically cleave a host of cellular substrates at aspartate residues, which may render them either functionally inactive or confer novel activities that help to promote cellular demise. Substrates targeted by caspases during the apoptotic programme include proteins involved in maintaining various aspects of cytoskeletal and organelle architecture as well as proteins that function in signalling networks critical for cell function. Following the execution phase of apoptosis, the cellular corpse is packaged in an orderly fashion into membrane‐bound apoptotic bodies that are sensed by phagocytes, which neatly engulf the dead cell without eliciting an immune response.

Key concepts:

Apoptotic caspases are cysteine proteases which become activated in response to diverse extracellular and intracellular stimuli and subsequently carry out the cell death programme by systematically cleaving intracellular proteins.

A hierarchy of caspase activation exists whereby initiator caspases become activated to cleave and activate effector caspases, which then dismantle the cell through proteolytical cleavage of intracellular.

The cellular morphological changes associated with apoptosis encompass three stages: release, membrane blebbing and condensation.

Caspase‐mediated cleavage of target proteins may produce stable functional effector fragments or unstable fragments that are quickly degraded.

Caspases target multiple aspects of the cellular architecture to induce collapse of organelles and the cytoskeleton.

Signalling networks that regulate cellular processes critical for cell survival are inactivated by caspases.

As the dying cell is dismantled during the apoptotic process, it orchestrates its own disposal by displaying ‘eat me’ signals on its cell surface and releasing ‘find me’ signals to recruit phagocytic cells.
Evolution of the Dog Genome
Authors: Webster Matthew T , Karlsson Elinor K
Published: December 2009

The dog genome illuminates several important features of mammalian genome evolution. The dog is a distant relative to the primate and rodent clades, so its genome sequence can be used to identify genetic changes that occurred on these lineages and as an aid in annotating the human genome. The dog also has a complex population history, shaped by ancient domestication events and, recently, strong artificial selection to form distinct breeds. The dog genome sequence enabled studies that shed light on canid phylogeny, revealing that this history created a genomic haplotype structure that is highly amenable to the association mapping. Dogs also exhibit enormous phenotypic variation and suffer from many of the same disorders as humans, making them a powerful model organism for identifying genetic variants responsible for many common traits and diseases including cancer, diabetes, autoimmune disorders and epilepsy.

Key concepts:

The dog is distantly related to the primate and rodent clades.

Dog genome evolution was characterized with a large number of chromosomal fissions and a low activity of transposons.

Genetic evidence supports an ancient origin of dogs in East Asia.

Dog domestication involved two population bottlenecks, one during dog domestication, over 15 000 years ago, and one during the formation of modern breeds in the past few hundred years.

Modern dog breeds exhibit remarkable phenotypic diversity and increased rates of common diseases shared with humans, including cancer, diabetes, autoimmune disorders and epilepsy.

Patterns of genetic variation in dogs are highly amenable to trait mapping by association studies.
Death Receptors at the Molecular Level: Therapeutic Implications
Authors: MacFarlane Marion
Published: December 2009

Since the discovery that activation of a subset of cell surface receptors within the tumour necrosis factor (TNF) receptor superfamily could trigger apoptosis, several members of the TNF superfamily including TNF, CD95L and TNF‐related apoptosis‐inducing ligand (
TRAIL
) have been identified as potentially important targets for cancer therapy. Although systemic administration of TNF or CD95L causes severe toxic side effects, thus hampering their potential application in the clinic, the discovery of
TRAIL
and its cognate death receptors,
TRAIL‐R1
and
TRAIL‐R2
, have provided an exciting new opportunity for selective targeting of tumour cells.
TRAIL
receptor activation has emerged as the most promising approach for death receptor‐targeted therapy while inducing minimal toxicity in the majority of normal cells. Intensive research, including detailed analysis of death ligand–death receptor pairs at the structural level have enabled the development of several different approaches aimed at selective targeting of
TRAIL‐R1/TRAIL‐R2
in tumour cells.

Key concepts:

Death receptor ligands, including CD95L and tumour necrosis factor (TNF)‐related apoptosis‐inducing ligand (TRAIL), are potent stimulators of apoptosis.

Unlike TNF and CD95L, which on systemic administration exhibit toxicity, TRAIL is selectively toxic to tumour cells while sparing most normal cells.

Although the molecular basis for the tumour selective activity of TRAIL remains to be fully defined, the TRAIL pathway is an attractive therapeutic target for the treatment of cancer.

Key discoveries at the structural level have revealed several important features of the molecular interaction between TRAIL and its cognate death receptors, TRAIL‐R1/ TRAIL‐R2, that are critical for TRAIL‐receptor triggering of apoptosis.

Based on structural and predicted models of TRAIL in complex with TRAIL‐R1/ TRAIL‐R2, recombinant TRAIL, receptor‐selective TRAIL variants, as well as anti‐TRAIL receptor antibodies have been developed, thus providing the opportunity to target both receptors or selectively target either TRAIL‐R1 or TRAIL‐R2 in tumour cells.

In preclinical trials, recombinant forms of TRAIL and agonistic anti‐TRAIL receptor antibodies can synergise with chemotherapeutic drugs and novel chemotherapeutic agents to effectively kill TRAIL‐resistant primary tumour cells.

Although early phase clinical trials indicate these agents can be delivered safely and are generally well tolerated as monotherapies, the most attractive use of these agents and their greatest promise for further clinical development will be when used in combination with other cancer treatments.
Micrometer‐Sized Specimen Preparation Based on Ion Slicing Technique
Authors: Wurster Stefan , Motz Christian , Jenko Monika , Pippan Reinhard
Published: December 2009

The ion slicing technique has been well known for producing samples for transmission electron microscopy (TEM) investigations. It will be shown that this method can also be used for producing different types of samples for micro‐mechanical experiments. The capability of manufacturing thin freestanding lamellae with a width of some micrometers and subsequently cantilevers and tensile testing specimens on the micrometer‐scale using the focused ion beam (FIB) technique will be demonstrated.
Synthesis of 2‐(N‐arylimino)pyrrolide nickel complexes and polymerization of methyl methacrylate
Authors: Li Jianfeng , Song Haibin , Cui Chunming
Published: December 2009

The synthesis, characterization and methyl methacrylate polymerization behaviors of 2‐(N‐arylimino)pyrrolide nickel complexes are described. The nickel complex [NN]2Ni (1, [NN] = [2‐C(H)NAr‐5‐tBu‐C4H2N]−, Ar = 2,6‐iPr2C6H3) was prepared in good yield by the reaction of [NN]Li with trans‐[Ni(Cl)(Ph)(PPh3)2] in THF. Reaction of [NN]Li with NiBr2(DME) yielded the nickel bromide [NN]Ni(Br)[NNH] (2). Complexes 1 and 2 were characterized by 1H NMR and IR spectroscopy and elemental analysis, and by X‐ray single crystal analysis. Both complexes, upon activation with methylaluminoxane, are highly active for the polymerization of methyl methacrylate to give high molecular weight polymethylmethacrylate with narrow molecular distributions. Copyright © 2009 John Wiley & Sons, Ltd.
Reactivity of organosilicon precursors in remote hydrogen microwave plasma chemical vapor deposition of silicon carbide and silicon carbonitride thin‐film coatings
Authors: Wrobel A. M. , Walkiewicz‐Pietrzykowska A. , Blaszczyk‐Lezak I.
Published: December 2009

A number of organosilicon precursors for silicon carbide and silicon carbonitride thin‐film coatings, such as silanes, carbosilanes, aminosilanes, and disilazane, respectively, were characterized in terms of their reactivity in a remote microwave plasma chemical vapor deposition process, which was induced using hydrogen as plasma generating gas. The process displayed high selectivity with respect to the activating species and the chemical bonds in the molecular structure of the precursors. In view of very short life times of excited hydrogen plasma species the activation step takes place with an exclusive contribution of ground‐state hydrogen atoms. The CH, CC, SiC, SiN, CN and NH bonds present in the molecules of the precursors are non‐reactive and only the SiH or SiSi bonds play a key role in the activation step. The reactivity of the precursors was characterized in a quantitative way by the yield of the film growth parameter. The yield parameter expressing the mass of film per unit mass of the precursor fed to the reactor was calculated from the slopes of linear plots of time dependencies of film mass and precursor mass, which were determined for each investigated precursor. The reactivity of the precursors was found to be strongly dependent on the number of the SiH units present in their molecules and those containing two SiH units appeared to be most reactive. Copyright © 2009 John Wiley & Sons, Ltd.
Bis(imino)pyridine palladium(II) complexes as efficient catalysts for the Suzuki–Miyaura reaction in water
Authors: Liu Ping , Yan Mei , He Ren
Published: December 2009

Bis(imino)pyridine palladium(II) complexes 3 and 4 of type [PdCl(L)PF6] are found to be efficient catalysts for Suzuki–Miyaura reactions of aryl halides and arylboronic acids. The reactions proceed smoothly to generate the corresponding biaryl compounds in moderate to excellent yields. The synthesis of various fluorinated biphenyl derivatives was successfully achieved by the complex 4 catalyzed the Suzuki–Miyaura reaction in the presence of surfactants bearing a long alkyl chain. Copyright © 2009 John Wiley & Sons, Ltd.
New chiral phosphinite ligands with C2‐symmetric axis and their possible applications in Ru‐catalyzed asymmetric transfer hydrogenation
Authors: Aydemir Murat , Meric Nermin , Baysal Akın , Kayan Cezmi , Toǧrul Mahmut , Gümgüm Bahattin
Published: December 2009

The new chiral ligands N,N′‐bis‐[(1R)‐1‐ethyl‐2‐O‐(diphenylphosphinite)ethyl]ethanediamide, 1, and N,N′‐bis‐[(1S)‐1‐isobutyl‐2‐O‐(diphenylphosphinite)ethyl]ethanediamide, 2, and the corresponding ruthenium complexes 3 and 4 were prepared and their structures were elucidated by a combination of multinuclear NMR spectroscopy, IR spectroscopy and elemental analysis. Following activation by NaOH, these chiral ruthenium complexes serve as catalyst precursors for the asymmetric transfer hydrogenation of acetophenone derivatives in iPrOH. The complexes 3 and 4 showed high catalytic activity but low selectivity in asymmetric transfer hydrogenation reactions. Copyright © 2009 John Wiley & Sons, Ltd.
CH bond functionalization of aromatic heterocycles with chelating dicarbene palladium(II) and platinum(II) complexes
Authors: Buscemi Gabriella , Biffis Andrea , Tubaro Cristina , Basato Marino , Graiff Claudia , Tiripicchio Antonio
Published: December 2009

Chelating dicarbene complexes of palladium(II) and platinum(II) catalyse at room temperature with 1% catalyst loading the reaction of ethyl phenylpropiolate with aromatic heterocycles to yield synthetically useful intermediates for fine chemicals without the need to use prefunctionalized substrates. The reaction outcome was found to be strongly dependent on the nature of the anionic ligands at the metal complex. Addition of silver salts to replace halide ligands with more weakly coordinating anions improves the reaction yield and changes the product distributions: heterocyclealkyne 2:1 adducts are obtained together with the usual hydroarylation products, which potentially broadens the scope of the reaction. The nature of the employed heterocycle, in particular its steric characteristics, is also found to strongly influence the outcome of the reaction. Copyright © 2009 John Wiley & Sons, Ltd.
Reduction of nitroarenes followed by propanol group transfer from tris(3‐hydroxypropyl)‐ amine and cyclization leading to quinolines under heterogeneous PdC catalysis
Authors: Cho Chan Sik , Kim Tae Gyun , Yoon Nam Sik
Published: December 2009

Nitroarenes having electron‐donating or ‐withdrawing substituents are reduced to anilines and cyclized with tris(3‐hydroxypropyl)amine in the presence of a catalytic amount of PdC along with tin(II) chloride and isopropanol in dioxane‐H2O medium to give the corresponding quinolines in good to excellent yields. Copyright © 2009 John Wiley & Sons, Ltd.
Long‐chain silanes as reducing agents part 1: a facile, efficient and selective route to amine and phosphine‐stabilized active Pd‐nanoparticles
Authors: Chauhan Bhanu P. S. , Thekkathu Ramani , Prasanth K Leon , Mandal Manik , Lewis Kenrick
Published: December 2009

Recently, metal nanoparticles have found applications in various fields, which have necessitated exploration of new avenues to obtain such materials. In this publication, a hydrosilane‐based reduction and characterization of resulting palladium nanoparticles is achieved using palladium acetate as nanoparticle precursor and octadecylsilane as a reducing agent. The influence of phosphine and amine ligands in the stabilization of nanoparticles is also investigated. In addition, a brief mechanistic proposal of the reduction process is also discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Viscosity of siloxane gum and silicone rubbers
Authors: Crawford B. , Doherty A. P. , Spedding P. L. , Herron W. , Proctor M.
Published: December 2009

Organo‐silicone compounds are widely used, have many desirable industrial properties and can exist in many different forms. Extrusion is the most commonly used manufacturing process of silicone products, and it is hoped that application of computational fluid dynamics (CFD) will elicit a better understanding of the underlying controlling mechanisms. In this work experimental data on viscoelastic properties obtained from rotational rheometry are presented for siloxane gums and silicone rubbers which, together with previous data on capillary viscometry and wall slip, will enable CFD simulations to be obtained which are more aligned to real behaviour. A general storage, loss moduli, viscosity curve was developed for the gum with an activation energy of 17.36 kJ mol−1. The equivalent could not be made from the room temperature rubber compound data. Wall slip occurred at all stress levels. A critical stress level necessary before slip took place may only be relevant for pressure‐driven flows. The Cox–Merz relation was of limited use. Die swell reduced with increased filler concentration but the extensional viscosity was found to increase. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd.
In situ preparation, electrospinning, and characterization of polyacrylonitrile nanofibers containing silver nanoparticles
Authors: Sichani G.Naddaf , Morshed M. , Amirnasr M. , Abedi D.
Published: December 2009

Silver nanoparticles were prepared from a polyacrylonitrile (PAN)/N,N‐dimethylformamide solution of silver nitrate (0.05–0.5 wt %) with light treatment (xenon arc) to reduce Ag+ ions into Ag0. The formation of silver nanoparticles in the PAN solution and the effect of treatment time on the numbers of silver nanoparticles, their average diameter and size distribution were investigated by UV–visible spectroscopy. In addition, the average size of silver nanoparticles and their shapes in colloidal solution were determined by transmission electron microscopy images and found to be on the order of 10 nm. The resulting solution was electrospun into PAN nanofibers. An increase in the salt concentration led to decreases in the nanofiber diameter and bead numbers (determined by scanning electron microscopy images) and an increase in the crystallinity (confirmed by X‐ray diffraction patterns). A continuous rate of silver release from the nanofiber web was monitored by the atomic absorption technique. These nanofibers showed strong antibacterial activity against Pseudomonas aeruginosa. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Open porous emulsion‐templated monoliths: Effect of the emulsion preparation conditions on the foam microstructure and properties
Authors: Abbasian Z. , Moghbeli M. R.
Published: December 2009

Highly open porous polymer foams were prepared via the polymerization of 10 : 1 styrene/divinylbenzene high‐internal‐phase emulsions (HIPEs) prepared under various emulsifying conditions. The effects of the emulsification stirring speed (SS) and rate of aqueous droplet‐phase addition on the HIPE equilibrium torque value, an approximate characterization of HIPE viscosity, and the microstructure and properties of the resulting HIPE polymer solid foams were investigated. SS was varied over the range 400–1200 rpm for aqueous‐droplet‐phase addition rates (AARs) of 0.53 and 1.3 mL/min. The microscopic results showed that at lower AARs, increasing SS decreased the weighted‐average cell diameter from 24.31 to 13.55 μm, whereas the cell size distribution was broadened, and the intercellular pore size varied irregularly in the range 0.76–1.42 μm. The average cell diameter and intercellular pore size for the solid foams prepared at higher AARs were greater than that of those prepared at lower AARs. The density of the foam materials ranged from 0.057 to 0.072 g/cm3, whereas their thermal conductivity varied from 0.649 to 0.705 W m−1 °C−1. The highest compressive stress–strain properties were found for the foam sample prepared with highest SS and a lower AAR. Adding electrolyte CaCl2 to HIPE produced remarkable increases in the void diameter and intercellular pore size, especially at lower SS values. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of the coagulation‐bath temperature on the phase‐separation process of poly(vinylidene fluoride)‐graft‐poly(N‐isopropylacrylamide) solutions and membrane structures
Authors: Guo Yanfen , Feng Xia , Chen Li , Zhao Yiping , Bai Jingna
Published: December 2009

A poly(vinylidene fluoride)‐graft‐poly(N‐isopropylacrylamide) (PVDF‐g‐PNIPAAm) copolymer was synthesized, and flat‐sheet membranes were prepared via the phase‐inversion method with N,N‐dimethylformamide (DMF) as the solvent and water as the coagulation bath. The effects of the coagulation‐bath temperature on poly(vinylidene fluoride) (PVDF)/DMF/water and PVDF‐g‐PNIPAAm/DMF/water ternary systems were studied with phase diagrams. The results showed that the phase‐separation process could be due to the hydrophilicity/hydrophobicity of poly(N‐isopropylacrylamide) at low temperatures, and the phase‐separation process was attributed to crystallization at high temperatures. The structures and properties of the membranes prepared at different coagulation‐bath temperatures were researched with scanning electron microscopy, porosity measurements, and flux measurements of pure water. The PVDF‐g‐PNIPAAm membranes, prepared at different temperatures, formed fingerlike pores and showed higher water flux and porosity than PVDF membranes. In particular, a membrane prepared at 30°C had the largest fingerlike pores and greatest porosity. The water flux of a membrane prepared in a 25°C coagulation bath showed a sharp increase with the temperature increasing to about 30°C. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The effects of the pH value of the swelling medium on the kinetics of the swelling of a poly(acrylic acid) hydrogel
Authors: Jovanovic Jelena , Adnadjevic Borivoj , Kostic Aleksandar
Published: December 2009

The isothermal kinetics curves of the swelling of a poly(acrylic acid) hydrogel in buffer solutions of different pH values (5, 7, and 9) at temperatures ranging from 30 to 40°C were determined. The possibilities of applying the Fick kinetics model and the Peppas equation were examined. It was found that the applicability of these models were limited. The kinetics model of a first‐order chemical reaction was found to describe the swelling kinetics of the PAA hydrogel in all the investigated buffer solution at all the investigated temperatures. Swelling kinetics is determined by the rate of expansion of the network. The kinetic parameters (Ea, ln A) of the swelling of the PAA hydrogel in buffer solutions of different pH values were determined. The activation energy and the pre‐exponential factor of the swelling of the PAA hydrogel in buffer medium decreased with increasing pH value of the swelling medium. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterization of poly(ester‐ether‐imide)s derived from 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene
Authors: Behniafar Hossein , Ghorbani Mostafa
Published: December 2009

A series of novel aromatic poly(ester‐ether‐imide)s with inherent viscosity values of 0.44–0.74 dL g−1 were prepared by the diphenylchlorophosphate‐activated direct polycondensation of an imide ring‐containing diacid namely 5‐(4‐trimellitimidophenoxy)‐1‐trimellitimido naphthalene (1) with various aromatic dihydroxy compounds in the presence of pyridine and lithium chloride. Owing to comparison of the characterization data, an ester‐containing model compound (2) was also synthesized by the reaction of 1 with phenol. The model compound 2 and the resulted polymers were fully characterized by FT‐IR and NMR spectroscopy. The ultraviolet λmax values of the poly(ester‐ether‐imide)s were also determined. The resulting polymers exhibited an excellent organosolubility in a variety of high polar solvents such as N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethyl sulfoxide, and N‐methyl‐2‐pyrrolidone. They were soluble even in common less polar organic solvents such as pyridine, m‐cresol, and tetrahydrofuran on heating. Crystallinity of the polymers was estimated by means of wide‐angle X‐ray diffraction. The resulted polymers exhibited nearly an amorphous nature. From differential scanning calorimetry thermograms, the polymers showed glass‐transition temperatures between 221 and 245°C. Thermal behaviors of the obtained polymers were characterized by thermogravimetric analysis, and the 10% weight loss temperatures of the poly(ester‐ether‐imide)s were found to be over 410°C in nitrogen. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Hydride addition of methylhydridesiloxanes to conjugated cyclohexa‐1,3‐diene
Authors: Mukbaniani O. , Tatrishvili T. , Koberidze Kh. , Scherf U.
Published: December 2009

The reaction of hydride polyaddition of methylhydridesiloxanes to conjugated cyclohexa‐1,3‐diene, in the presence of catalytic amount of platinum hydrochloric acid, has been investigated at several temperatures. The polyorganosiloxanes with cyclohexenyl fragments in the side chain, completely soluble in organic solvents, were synthesized. The hydride polyaddition reaction order, activation energies, and rate constants were found. By quantum‐chemical half‐empirical method AM1, the electronic characteristics of cyclohexa‐1,3‐diene: the charges on the carbon atoms and bonds orders were calculated. For full characterization of hydrosilylation reaction, calculations for modeling reaction between methyldimethoxysilane and cyclohexa‐1,3‐diene were carried out using Gaussian 03 program package. The geometries of reactants, transition states, and products were optimized using PM3 semiempirical method followed by single‐point calculations at B3LYP/6‐31G(d) level of density functional theory. It was concluded that the course of hydride addition of modeling reaction of methyldimethoxysilane to cyclohexa‐1,3‐diene energetically is more favorable by 1,4‐addition. The synthesized oligomers were characterized by FTIR, 1H‐ and 13C‐NMR spectroscopy, thermogravimetry, gel permeation chromatography, differential scanning calorimetry, and wide‐angle X‐ray diffractometry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
The synthesis of water soluble cationic microgels by dispersion polymerization: Their performance in kaolin deposition onto fiber
Authors: Ondaral Sedat , Usta Mustafa , Gumusderelioglu Menemse , Arsu Nergis , Balta Demet Karaca
Published: December 2009

The water soluble cationic microgels (CMG), intramolecularly cross‐linked cationic polymers of acrylamide (Am) and diallyldimethylammonium chloride (DADMAC), were synthesized with dispersion polymerization in the mixture of tert‐butanol (TBA)/water in the presence N,N′‐methylene‐bisacrylamide (MBA) as the cross‐linker, poly(N‐vinylpyrrolidone (PVP) as the stabilizer and 2,2′‐azobisisobutyronitrile (AIBN) as the initiator. The effects of monomer, cross‐linker, initiator, and stabilizer concentration on both particle size and molecular weight of CMG were investigated. The well dispersed polymer particles were produced in the range of poly dispersity index 1.1–1.4 and the molecular weight distribution with bimodal. Additionally, the efficiencies of two CMGs in the clay deposition on the bleached kraft fibers were investigated and compared with commercially widely used cationic polyacrylamide (CPAM) and poly‐diallyldimethylammonium chloride (poly‐DADMAC). The experiments showed that the CMGs were found as the effective flocculation agents and their efficiencies depended on their molecular weight and charge density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effective method for dispersing SiO2 nanoparticles into polyethylene
Authors: Pöllänen Maija , Pelz Uwe , Suvanto Mika , Pakkanen Tuula T.
Published: December 2009

An effective solution mixing method starting from a synthesis solution of SiO2 nanoparticles was developed for dispersing nanoparticles into high‐density polyethylene (HDPE). Spherical SiO2 nanoparticles with narrow size distribution (50–100 nm) were prepared by Stöber method, and solvents of the synthesis solution (EtOH/NH4OH) were gradually replaced with toluene by evaporation under reduced pressure. The SiO2 nanodispersion, in toluene and residual ethanol, was mixed and refluxed with dissolved maleic anhydride grafted polyethylene (PEgMA) at a relatively high SiO2 content (17.8 wt %). The PEgMA‐SiO2 masterbatch was filtered, dried under vacuum, and mixed with HDPE by melt compounding. SiO2 contents in the final HDPE nanocomposites were 3 and 5 wt %. SEM images of the masterbatch and final composites showed the SiO2 nanoparticles to be well dispersed in HDPE. No agglomerates were observed. FTIR results suggest that the interactions between the maleic anhydride group of PEgMA and hydroxyl groups of SiO2 surface involve ester and/or hydrogen bonding. Addition of SiO2 particles and PEgMA to HDPE slightly increased Young's modulus, tensile strength, breaking strength, and elongation at break, indicating enhanced toughness of the nanocomposites. The measured Young's moduli of HDPE‐PEgMA‐SiO2 composites agreed well with Young's moduli predicted by Mori‐Tanaka composite theory. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Poly(pyridinium salt)s with organic counterions derived from an aromatic diamine containing tetraoxyethylene units exhibiting amphotropic liquid‐crystalline and photoluminescence properties
Authors: Bhowmik Pradip K. , Han Haesook , Nedeltchev Alexi K. , Mandal Hari D. , Jimenez‐Hernandez Jose A. , Mcgannon Patrick M.
Published: December 2009

Several poly(pyridinium salt)s containing various organic counterions and tetraoxyethylene units in their backbones were synthesized by either ring‐transmutation polymerization reaction of 4,4'‐(1,4‐phenylene)bis(2,6‐diphenylpyrylium tosylate) with bis(2‐(2‐(4‐aminophenoxy)ethoxy)ethyl) ether on heating in dimethyl sulfoxide or metathesis reaction of the tosylate polymer with the corresponding lithium or sodium salts in acetonitrile. Their chemical structures were determined by 1H‐NMR and 13C‐NMR spectroscopy, and elemental analyses. Their number‐average molecular weights and polydispersity indices were in the range of 34,000–52,000 and 1.14–1.38, respectively, as determined by gel permeation chromatography. They were characterized both for their thermotropic and lyotropic liquid‐crystalline properties by using differential scanning calorimetry and polarizing optical microscopy. As these polymers exhibited liquid‐crystalline phase both in the melt and in solutions, they are classified as an amphotropic class of ionic polymers. Their light‐emitting properties in a large number of organic solvents that ranged from nonpolar to polar solvents and in films cast from methanol and acetonitrile were also studied by using spectrofluorometry. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
G protein‐coupled receptors: the inside story
Authors: Jalink Kees , Moolenaar Wouter H.
Published: December 2009

Recent findings necessitate revision of the traditional view of G protein‐coupled receptor (GPCR) signaling and expand the diversity of mechanisms by which receptor signaling influences cell behavior in general. GPCRs elicit signals at the plasma membrane and are then rapidly removed from the cell surface by endocytosis. Internalization of GPCRs has long been thought to serve as a mechanism to terminate the production of second messengers such as cAMP. However, recent studies show that internalized GPCRs can continue to either stimulate or inhibit cAMP production in a sustained manner. They do so by remaining associated with their cognate G protein subunit and adenylyl cyclase at endosomal compartments. Once internalized, the GPCRs produce cellular responses distinct from those elicited at the cell surface.
Enantiomeric separation of 2‐arylpropionic acid nonsteroidal anti‐inflammatory drugs by HPLC with hydroxypropyl‐β‐cyclodextrin as chiral mobile phase additive
Authors: Ye Jincui , Yu Wenying , Chen Guosheng , Shen Zhengrong , Zeng Su
Published: December 2009

The enantio‐separations of eight 2‐arylpropionic acid nonsteroidal anti‐inflammatory drugs (2‐APA NSAIDs) were established using reversed‐phase high‐performance liquid chromatography with hydroxypropyl‐β‐cyclodextrin (HP‐β‐CD) as chiral mobile phase additive for studying the stereoselective skin permeation of suprofen, ketoprofen, naproxen, indoprofen, fenoprofen, furbiprofen, ibuprofen and carprofen. The effects of the mobile phase composition, concentration of HP‐β‐CD and column temperature on retention and enantioselective separation were investigated. With 2‐APA NSAIDs as acidic analytes, the retention times and resolutions of the enantiomers were strongly related to the pH of the mobile phase. In addition, both the concentration of HP‐β‐CD and temperature had a great effect on retention time, but only a slight or almost no effect on resolutions of the analytes. Enantioseparations were achieved on a Shimpack CLC‐ODS (150 × 4.6 mm i.d., 5 μm) column. The mobile phase was a mixture of methanol and phosphate buffer (pH 4.0–5.5, 20 mM) containing 25 mM HP‐β‐CD. This method was flexible, simple and economically advantageous over the use of chiral stationary phase, and was successfully applied to the enantioselective determination of the racemic 2‐APA NSAIDs in an enantioselective skin permeation study. Copyright © 2009 John Wiley & Sons, Ltd.
Fragmentation study of iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae by rapid resolution liquid chromatography with diode‐array detection and electrospray ionization time‐of‐flight mass spectrometry
Authors: Wu Qian , Yuan Quan , Liu E‐Hu , Qi Lian‐Wen , Bi Zhi‐Ming , Li Ping
Published: December 2009

Rapid resolution liquid chromatography (RRLC) coupled with diode array detection (DAD) and electrospray ionization time‐of‐flight mass spectrometry (ESI‐TOF MS) method was applied to the mass spectral study of a series of naturally occurring iridoid glycosides and phenylpropanoid glycosides in Radix Scrophulariae, which provides higher speed and increased sensitivity without loss of resolution. With dynamic adjustment as the key role of the fragmentor voltage and confirmed with authentic standards, valuable structural information regarding the nature of both the glycoside skeletons was thus obtained. Most compositions were found to possess organic acid moiety such as cinnamoyl, caffeoyl and ferulyol. Besides extensive fragmentation of the carbohydrate moiety, losses of the hydroxyl and glucose residue units showed in the spectra, permitting the exploration of the skeleton and the identity of substituents in the molecule. Ten major iridoid glycosides and 10 phenylpropanoid glycosides were identified or tentatively characterized based on their retention times, UV and TOF MS data. The major fragmentation pathways of PGs in Radix Scrophulariae obtained through the MS data was schemed systematically for the first time, which provides a reference for other PGs derivatives. Copyright © 2009 John Wiley & Sons, Ltd.
A sensitive and specific HPGPC‐FD method for the study of pharmacokinetics and tissue distribution of Radix Ophiopogonis polysaccharide in rats
Authors: Lin Xiao , Wang Zhuojun , Sun Guilan , Shen Lan , Xu Desheng , Feng Yi
Published: December 2009

Interest in antimyocardial ischemic activity of a graminan‐type fructan with a weight average molecular weight of 4.8 kDa extracted from Radix Ophiopogonis (ROP) has necessitated the study of its pharmacokinetics and tissue distribution. For that, a simple HPGPC–FD method was developed for the sensitive and specific determination of FITC‐ROP (fluorescein–isothiocyanate‐labeled ROP) in plasma and rat tissues (heart, liver, spleen, lung, kidney, brain and stomach). The analyte was separated on a Shodex Sugar KS‐802 high‐performance gel column with 0.1 M phosphate buffer (pH 7.0) as mobile phase at a flow rate of 0.5 mL/min, and fluorescence detection at λex 495 nm and λem 515 nm. The calibration curve for FITC‐ROP was linear over the range 0.25–20.0 or 50.0 μg/mL in all studied biosamples with correlation coefficients >0.995. The inter‐day and intra‐day precisions of analysis were not more than 10%, and assay accuracy ranged from 93 to 105% for plasma and from 89 to 108% for tissue homogenates. This method has been confirmed here to be suitable for the study of pharmacokinetics and tissue distribution of ROP and the achieved results are highly instructive for the further pharmaceutical development of ROP, suggesting the promising application of the method to the increasingly important carbohydrate‐based drugs. Copyright © 2009 John Wiley & Sons, Ltd.
Synthesis and Biophysical Studies of Bis‐Macrocyclic Cobalt/Copper(II) Complexes Having a Pyridine Spacer with CT DNA and 5′‐GMP
Authors: Arjmand Farukh , Aziz Mubashira
Published: December 2009

New bis‐macrocyclic complexes of CoIII, 1, NiII, 2, and CuII, 3, containing pyridyl bridges between 13‐membered macrocyclic subunits, have been synthesized via an in situ one‐pot template condensation reaction (IOPTCR). The proposed structures of these new dinuclear complexes are consistent with the data obtained from elemental analysis, molar conductance, IR, EPR, UV/VIS, 1H‐ and 13C‐NMR, and ESI‐MS. The complexes 2 and 3 possess square‐planar geometry with four secondary N‐atoms coordinated to the metal ion, while complex 1 reveals octahedral geometry in solution due to coordinated H2O molecules. DNA‐Binding properties of the complexes 1 and 3 were investigated by absorption and emission titrations, cyclic voltammetry, and viscosity measurements. Complexes 1 and 3 are strong DNA binders with binding constants, Kb, of 1.64×105 and 2.05×105 M−1, respectively. Hyperchromism, decrease in emission intensity of DNA‐bound ethidium bromide (EB), and changes observed in the viscosity and cyclic voltammograms in the presence of added metal complexes reveals that the complexes bind to DNA predominantly by electrostatic attraction, substantiated by absorption titration with 5′‐GMP.
Chemical Variability of the Needle Oil of Juniperus communis ssp. alpina from Corsica
Authors: Ottavioli Josephine , Gonny Marcelle , Casanova Joseph , Bighelli Ange
Published: December 2009

The composition of 109 samples of essential oil isolated from the needles of Juniperus communis ssp. alpina growing wild in Corsica was investigated by GC (in combination with retention indices), GC/MS, and 13C‐NMR. Forty‐four compounds accounting for 86.7–96.7% of the oil were identified. The oils consisted mainly of monoterpene hydrocarbons, in particular, limonene (9.2–53.9%), β‐phellandrene (3.7–25.2%), α‐pinene (1.4–33.7%), and sabinene (0.1–33.6%). The 109 oil compositions were submitted to k‐means partitioning and principal component analysis, which allowed the distinction of two groups within the oil samples. The composition of the major group (92% of the samples) was dominated by limonene and β‐phellandrene, while the second group contained mainly sabinene beside limonene and β‐phellandrene.
The Essential Oil of Bupleurum fruticosum L. from Corsica: A Comprehensive Study
Authors: Liu Kai , Lota Marie Laure , Casanova Joseph , Tomi Félix
Published: December 2009

A detailed analysis of Bupleurum fruticosum oil was carried out by combination of GC (RI), GC/MS, and 13C‐NMR analyses. After fractionation by column chromatography, 34 components accounting for 97.8% of the oils were identified. The main component was β‐phellandrene (67.7%), followed by sabinene (9.3%), and limonene (5.6%). The evolution of the chemical composition according to the stages of development of the plant was investigated as well as the composition of leaf, twig, and flower oils. A solvent‐free microwave extraction (SFME) of aerial parts was carried out and the composition of the extract compared with that of the essential oil. Finally, 57 oil samples isolated from aerial parts of individual plants, collected all around Corsica, were analyzed, and the data were submitted to statistical analysis. Although the contents of the main components varied, only one group emerged, accompanied with some atypical compositions.