bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of contamination effects for two polypropylene‐based materials
Authors: Pessey Daniel , Bahlouli Nadia , Raveyre Claude , Guillet Jacques , Ahzi Said , Hiver Jean‐Marie , Dahoun Abdesselam
Published: October 2009

In this work, contamination effects are studied on two polypropylene‐based materials. These effects were identified on the molecular weight and on rheological and mechanical properties. Model contaminants chosen in this study were ethylene glycol and engine oil. They were added during the extrusion process to simulate the degradation due to contaminants. To quantify contamination effects and to correlate them with the microstructure evolution, scanning electron microscope (SEM) analyses were also conducted. The analysis of the different obtained results led to a better understanding of the mechanisms involved in the contamination process. Contaminants slightly affect the rheological properties, whereas mechanical properties are more influenced. These observations are confirmed by the modification of the fractured surfaces of the materials due to the presence of contaminants observed on SEM micrographs. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Effects of nanoparticle feed location during nanocomposite compounding
Authors: Ashter Ali , Tsai Su‐Jung , Lee Jun S. , Ellenbecker Michael J. , Mead Joey L. , Barry Carol F.
Published: October 2009

Polymer nanocomposites can provide improved mechanical, barrier, flame retardancy, and other properties at low filler loading, but these properties depend on the dispersion of the nanoparticles. In this work, the impact of feeding configuration on dispersion, mechanical properties, and airborne particle concentration was examined in a model nanocomposite system. Dynamic mechanical analysis and differential scanning calorimetry were performed to determine glass transition temperature of the nanocomposite. Transmission electron microscopy was used to assess dispersion of the nanoparticles in the polymer matrix whereas mechanical properties were measured using ISO standards. A fast mobility particle analyzer was used to measure airborne particle levels at from the hopper and the feed ports. These levels were correlated to the particle size and material loss. An indirect relationship was established among material loss, measured dispersion levels, and mechanical properties. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Birefringent approach for assessing the influence of the extrusion temperature profile on the overall orientation of as‐spun aliphatic‐aromatic co‐polyester fibers
Authors: Younes Basel , Fotheringham Alex , El‐Dessouky Hassan M.
Published: October 2009

Since the success of a production process depends on its good planning and having a clear plan from the raw materials until the final product, the focus of this research is in modeling of the extrusion temperature profile of as‐spun aliphatic‐aromatic co‐polyester fibers. The extrusion temperature profile affects the properties, productivity and product cost. In this work, as‐spun aliphatic‐aromatic co‐polyester fibers were spun under a fractional factorial design as a function of the extrusion temperature profile using appropriate statistical methods. The influence of the extrusion temperature profile on the optical birefringence of the as‐spun fibers was characterized. From the obtained results the overall orientation of the spun filaments has been modeled. For measuring the birefringence, an interferometric technique was employed and its microinterferograms were included for illustration. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
Determination of the heat transfer coefficient from short‐shots studies and precise simulation of microinjection molding
Authors: Nguyen‐Chung Tham , Jüttner Gábor , Löser Cindy , Pham Tung , Gehde Michael
Published: October 2009

The filling process of a micro‐cavity was analyzed by modeling the compressible filling stage by using pressure‐dependent viscosity and adjusted heat transfer coefficients. Experimental filling studies were carried out at the same time on an accurately controlled microinjection molding machine. On the basis of the relationship between the injection pressure and the filling degree, essential factors for the quality of the simulation can be identified. It can be shown that the flow behavior of the melt in a micro‐cavity with a high aspect ratio is extremely dependent on the melt compressibility in the injection cylinder. This phenomenon needs to be considered in the simulation to predict an accurate flow rate. The heat transfer coefficient between the melt and the mold wall that was determined by the reverse engineering varies significantly even during the filling stage. With increasing injection speed and increasing cavity thickness, the heat transfer coefficient decreases. It is believed that the level of the cavity pressure is responsible for the resulting heat transfer between the polymer and the mold. A pressure‐dependent model for the heat transfer coefficient would be able to significantly improve the quality of the process simulation. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers
Cyclodextrin polyrotaxanes assembled from a molecular construction kit in aqueous solution
Authors: Wenz Gerhard
Published: October 2009

We describe a molecular construction kit in which amphiphilic polymers and functionalized cyclodextrins are arranged into sophisticated molecular architectures in aqueous solution without the need to perform chemical reactions. Therefore, these systems are highly biocompatible and show programmable lifetimes. The kinetic stabilities of our polyrotaxane structures are tunable using sterically demanding groups that hinder dissociation. These cyclodextrin‐based polymer systems are applicable in principle for the detection of analytes at the level of single molecules. These systems may also serve well in targeted drug delivery and gene transfection. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6333–6341, 2009
Supported titanium‐magnesium catalysts for ethylene polymerization: A comparative study of catalysts containing isolated and clustered titanium ions in different oxidation states
Authors: Tregubov Andrey A. , Zakharov Vladimir A. , Mikenas Tatiana B.
Published: October 2009

Supported titanium–magnesium catalysts (TMC) comprising isolated and clustered titanium ions in different oxidation states, which are obtained using titanium compounds of different composition (TiCl4, TiCl3•nDBE (DBE – dibutyl ether), [η6–BenzeneTiAl2Cl8]), were synthesized and tested in ethylene polymerization. The state of titanium ions was studied by the ESR method both for the procatalysts and after their interaction with triisobutilaluminum. For identification of ESR‐silent Ti3+ ions and Ti2+ ions, special procedures of additional catalyst treatment with pyridine, water, and chloropentafluorobenzene were used to obtain Ti3+ ions that are observable in ESR spectra. In distinction to numerous earlier works performed with the TiCl4/MgCl2 catalyst comprising after the interaction with AlR3 the Ti3+ surface compounds both as isolated ions and clusters (ESR‐silent), this work considers the [η6–BenzeneTiAl2Cl8]/MgCl2 catalyst (TMC‐3) comprising mainly the isolated Ti2+ ions and a new catalyst TMC‐4 obtained by treating the TMC‐3 with chloropentafluorobenzene. This catalyst comprises only the isolated Ti3+ ions both before and after the interaction with triisobutylaluminum. It was shown that in spite of sharp distinctions between the catalysts under consideration concerning titanium oxidation state and the ratio of isolated Ti3+ ions to clustered ones, all these catalysts produce polyethylenes with similar molecular weights and molecular‐weight distributions. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6362–6372, 2009
Biocomplementary interaction behavior in DNA‐like and RNA‐like polymers
Authors: Cheng Chih‐Chia , Yen Ying‐Chieh , Ye Yun‐Sheng , Chang Feng‐Chih
Published: October 2009

A series of nucleobased polymers and copolymers were synthesized through atom transfer radical polymerization (ATRP). Biocomplementary DNA‐ and RNA‐like supramolecular complexes are formed in dilute DMSO solution through nucleobase recognition. 1H NMR titration studies of these complexes in CDCl3 indicated that thymine‐adenine (T‐A) and uracil‐adenine (U‐A) complexes form rapidly on the NMR time scale with high association constants (up to 534 and 671 M–1, respectively) and result in significant Tg increase. WAXD and differential scanning calorimetry analyzes in the bulk state indicate the presence of highly physical cross‐linked structures and provide further details into the nature of the self‐assembly of these systems. Furthermore, this study is of discussion on the difference in the hydrogen bond strength between T‐A and U‐A base pairs within polymer systems, indicating that the strength of hydrogen bonds in RNA U‐A pairs is stronger than that in DNA T‐A base pairs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6388–6395, 2009
Synthesis and properties of gradient copolymers based on 2‐phenyl‐2‐oxazoline and 2‐nonyl‐2‐oxazoline
Authors: Lambermont‐Thijs Hanneke M. L. , Jochems Mark J. H. C. , Hoogenboom Richard , Schubert Ulrich S.
Published: October 2009

In this study, the structure–property relationships for a series of statistical 2‐nonyl‐2‐oxazoline (NonOx) and 2‐phenyl‐2‐oxazoline (PhOx) copolymers were investigated for the first time. The copolymerization kinetics were studied and the reactivity ratios were calculated to berNonOx= 7.1 ± 1.4 andrPhOx= 0.02 ± 0.1 revealing the formation of gradient copolymers. The synthesis of a systematical series of NonOx–PhOx copolymers is described, whereby the amount of NonOx was increased in steps of 10 mol %. The thermal and surface properties were investigated for this series of well‐defined copolymers. The thermal properties revealed a linear decrease in glass transition temperature for copolymers containing up to 39 wt % NonOx. Furthermore, the melting temperature of the copolymers containing 0 to 55 wt % PhOx linearly decreased most likely due to disturbance of the NonOx crystalline domains by incorporation of PhOx in the NonOx part of the copolymer. The surface energies of spincoated polymer films revealed a strong decrease in surface energy upon incorporation of NonOx in the copolymers due to strong phase separation between NonOx and PhOx allowing the NonOx chains to orient to the surface. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6433–6440, 2009
Hyperbranched framework of interrupted π‐conjugated polymers end‐capped with high carrier‐mobility moieties for stable light‐emitting materials with low driving voltage
Authors: Liu Feng , Liu Ju‐Qing , Liu Ran‐Ran , Hou Xiao‐Ya , Xie Ling‐Hai , Wu Hong‐Bin , Tang Chao , Wei Wei , Cao Yong , Huang Wei
Published: October 2009

A novel series of soluble hyperbranched interrupted π‐conjugated polymers (HICPs) based on complicated 9,9‐diarylfluorenes (CDAFs) branching core and end‐capped with high carrier‐mobility pyrene moieties were synthesized via the “A2 + A′2 + B3” type Suzuki coupling condensation. The new polymer architecture improves the spectrum stability than the corresponding linear and hyperbranched polymers in PLEDs. Besides, it overcomes the drawback of high driving voltage of common interrupted π‐conjugated polymers. CDAF1 exhibits excellent thermal and morphological stability with a decomposition temperature (Td) higher than 445 °C and a glass transition temperature (Tg) up to 128 °C. No obvious low‐energy green emission band at 520 nm was observed under extreme thermal annealing conditions in air at 200 °C for 12 h. The CDAF1 device shows stable blue emission with the peak at 422 and 447 nm. The Commission International d'Eclairage (CIE) 1931 coordinates is (0.18, 0.16) and the brightness reaches 1051 cd/m2 at 15.7 V. White PLED based on CDAF1/MEH‐PPV blends exhibits a low turn‐on voltage of 4.8 V with voltage‐independent CIE of (0.32, 0.32). Molecular simulations were used to investigate the conformation and interchain interaction. HICPs based on CDAFs tethered with high‐mobility moieties are promising stable blue and host materials. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6451–6462, 2009
Supramacromolecular chemistry: Self‐assembly of polystyrene‐based multi‐armed pseudorotaxane star polymers from multi‐topic C60 derivatives
Authors: Gibson Harry W. , Ge Zhongxin , Jones Jason W. , Harich Kim , Pederson Adam , Dorn Harry C.
Published: October 2009

Multitopic dibenzylammonium derivatives (4) of C60 were prepared by Bingel reactions of C60 with a malonate diester (2) containing two t‐BOC protected dibenzylamine moieties, followed by deprotection and protonation. Self‐assembly of model pseudorotaxanes 5 from the multidibenzylammonium C60 derivatives with dibenzo‐24‐crown‐8 was studied by 1H NMR spectroscopy and mass spectrometry. Self‐assembly of linear and star‐shaped pseudorotaxanes 8 with up to 12 arms based on polystyrenes bearing terminal DB24C8 host units (7) and the guest functionalized C60 salts was demonstrated by 1H NMR spectroscopy and solution phase viscometry. These studies provide further evidence of the potential of supramacromolecular chemistry in construction of complex polymeric architectures. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 6472–6495, 2009
A theoretical investigation on the structures, densities, detonation properties, and pyrolysis mechanism of the nitro derivatives of phenols
Authors: Wang Guixiang , Gong Xuedong , Liu Yan , Xiao Heming
Published: October 2009

The nitro derivatives of phenols are optimized to obtain their molecular geometries and electronic structures at the DFT‐B3LYP/6‐31G* level. Detonation properties are evaluated using the modified Kamlet–Jacobs equations based on the calculated densities and heats of formation. It is found that there are good linear relationships between density, detonation velocity, detonation pressure, and the number of nitro and hydroxy groups. Thermal stability and pyrolysis mechanism of the title compounds are investigated by calculating the bond dissociation energies (BDEs) at the unrestricted B3LYP/6‐31G* level. The activation energies of H‐transfer reaction is smaller than the BDEs of all bonds and this illustrates that the pyrolysis of the title compounds may be started from breaking OH bond followed by the isomerization reaction of H transfer. Moreover, the CNO2 bond with the smaller bond overlap population and the smaller BDE will also overlap may be before homolysis. According to the quantitative standard of energetics and stability as a high‐energy density compound, pentanitrophenol essentially satisfies this requirement. In addition, we have discussed the effect of the nitro and hydroxy groups on the static electronic structural parameters and the kinetic parameter. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Theoretical study of the inhibitive properties of a group of benzimidazoles
Authors: Li Da‐Zhi , Zhang Shi‐Guo , Bian He
Published: October 2009

In this work, a group of benzimidazoles, namely benzimidazole (BIM), 2‐hexyl benzimidazole (2‐HBIM), and 2‐benzyl chloride benzimidazole (2‐ClBBIM), have been studied using density functional theory (DFT) at the level of B3LYP with the 6‐31G (d) and 6‐311G (d, p) base sets in order to elucidate the different inhibition efficiencies and reactive sites of these compounds as corrosion inhibitors. Based on the calculated results, the studied molecules interact with Fe‐atoms mainly in their stable pyridine‐N protonated forms. It is found that the inhibition efficiencies of the stable protonated molecules involved in this study have a certain relation with some parameters, such as the highest occupied molecular orbital energy (EHOMO) and the global hardness (η). The results indicate that the C (7) atoms, as the reactive sites, receive electrons from Fe‐atoms, benzene ring denote electrons to vacant orbital of Fe‐atoms. Additionally, Fukui indices and the orbital analyses suggest that 2‐ClBBIM has the highest reaction activity among the three molecules, the efficiency order of three inhibitors is found to be 2‐ClBBIM > 2‐HBIM > BIM, which accords with experimental results. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
First‐principles calculation of second‐order elastic constants and equations of state for lithium azide, LiN3, and lead azide, Pb(N3)2
Authors: Perger W. F.
Published: October 2009

First‐principle techniques are used to calculate the second‐order elastic constants and equations of state for lithium azide, LiN3, and lead azide, Pb(N3)2. The bulk modulus is calculated for these systems in two independent ways and results compared. The Hartree–Fock potential and density‐functional theory are used for the exchange correlation with different basis sets to examine the effects of each on the elastic constants and bulk modulus. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Quantum chemical study of dissociation of H2 on C3H3V organometallic compound
Authors: Kalamse Vijayanand , Wadnerkar Nitin , Chaudhari Ajay
Published: October 2009

We have studied H2 adsorption on C3H3V organometallic compound using density functional method at B3LYP/LanL2Dz level of theory. It was found that H2 molecule dissociates and adsorbed in dihydride form on this organometallic compound. Potential energy surface for H2 dissociation process was obtained and different properties such as HOMO–LUMO gap, dipole moment, interaction energies between different molecules and atoms, vibrational frequencies, and atomic charges during the dissociation process were studied. It was found that the C3H3V(H2) structure is most stable at HVH angle of 66.3°. Many‐body analysis was also carried out to determine the two‐body energies, three‐body energies, relaxation energy, and binding energy of the structures for each point on the potential surface. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2010
Dual Modification of Banana Starch: Partial Characterization
Authors: Carmona‐Garcia Roselis , Aguirre‐Cruz Andrés , Yee‐Madeira Hernani , Bello‐Pérez Luis A.
Published: October 2009

Banana starch was double modified by cross‐linking and substitution, using two different cross‐linking agents, i.e. phosphorus oxychloride (POCl3) and a mixture of sodium trimetaphosphate/sodium tripolyphosphate. The morphological and physicochemical properties and the absorption capacity for heavy metals of the modified starches were assessed. Double modified starch granules (cross‐linked carboxymethyl starches CCSA and CCSB) presented changes in the surfaces. These starches had a bigger average particle size than unmodified starch due to the swelling of the granules during the chemical modification, also aggregates were formed. The double modified banana starches presented an A‐type X‐ray diffraction pattern with slightly decreased crystallinity compared with the unmodified counterparts. The double modification of banana starch decreases the temperature and enthalpy of gelatinization and the decomposition temperature. These results are related to partial disorganization during the chemical treatment. The double modified banana starch possess sorption capacity for heavy metal ions in the order Cd2+ >Pb2+>Cu2+>Hg2+. Due to their physicochemical characteristics and absorption capacity, the double modified banana starches can be used in diverse applications.
A Study of the Internal Structure in Cassava and Rice Amylopectin
Authors: Laohaphatanaleart Kamlai , Piyachomkwan Kuakoon , Sriroth Klanarong , Santisopasri Vilai , Bertoft Eric
Published: October 2009

Cassava and rice amylopectins and their ϕ,β‐limit dextrins were debranched and the unit chain compositions were analyzed by gel permeation chromatography and high performance anion‐exchange chromatography. The content of amylose and super‐long amylopectin chains was 15.5‐15.6% and 0.8‐1.2% in cassava and 15.1‐18.7% and 3.4‐8.6% in rice starches, respectively. The internal unit chain profiles of the amylopectin samples were obtained from the ϕ,β‐limit dextrins. Short B‐chains were subdivided into a major group (BSmajor) with a degree of polymerization (DP) of 8‐25 and a minor group of “fingerprint” B‐chains (Bfp) with DP 3‐7. Cassava and rice amylopectins possessed different amounts and patterns of Bfp‐chains. The rice samples contained higher amounts of Bfp‐chains, which suggested larger size of its clusters when compared with cassava. The content of the shortest “fingerprint” A‐chains (Afp) was also variable, especially between the rice cultivars. The position of the internal chains in the original amylopectin chain profile was traced. The reconstructed B‐chain profiles fitted well with the original profiles. This implied that most of the B‐chains carried external chain segments of similar lengths, which corresponded to the experimentally measured average length.
Starch Phosphate Hydrogels. Part I: Synthesis by Mono‐phosphorylation and Cross‐linking of Starch
Authors: Passauer Lars , Liebner Falk , Fischer Klaus
Published: October 2009

Starch‐based hydrogels were synthesized by cross‐linking monostarch monophosphates (MSMP) with different di‐ and tricarboxylic acids such as succinic, adipic or citric acid. Phosphorylation of starch was performed in a semi‐dry process using a mixture of primary and secondary sodium phosphates. The phosphorus content and degree of substitution of phosphate groups (DSP) of the resulting MSMP were determined using a photometric method. For structural characterization of starch phosphates 31P NMR was used. Investigations showed that MSMP hydrogels were strong water absorbing polymer networks with a free swelling capacity (FSC) of up to 185 g water / g dry hydrogel.
Dopamine transporter PET in normal aging: Dopamine transporter decline and its possible role in preservation of motor function
Authors: Troiano André R. , Schulzer Michael , Fuente‐Fernandez Raul de La , Mak Edwin , Mckenzie Jess , Sossi Vesna , Mccormick Siobhan , Ruth Thomas J. , Stoessl A. Jon
Published: October 2009

Objectives: To determine the impact of age‐related decline in dopamine transporter (DAT) expression on motor function in the elderly.Methods: About 33 normal individuals of a wide age range were scanned with PET employingd‐threo‐[11C]‐methylphenidate (MP, a marker of DAT) and [11C]‐dihydrotetrabenazine (DTBZ, that binds to the vesicular monoamine transporter Type 2). Motor function was assessed using the Purdue Pegboard Test (PPB). We analyzed the relationship between [11C]‐MP and motor performance.Results: Age ranged from 27‐ to 77‐year old (mean ± SD, 54.75 ± 14.14). There was no age‐related decline in binding potentials (BP) for [11C]‐DTBZ. In contrast, [11C]‐MP BP was inversely related to age in all striatal regions analyzed (caudate: reduction of 11.2% per decade,P< 0.0001,r= −0.86; putamen: reduction of 10.5% per decade,P< 0.0001,r= −0.80). A differential effect of [11C]‐MP on PPB could be observed according to age group. There was a positive relation between the PPB and [11C]‐MP in young individuals (coefficient = 13.56), whereas in individuals greater than 57 years this relationship was negative (coefficient = −19.53,P= 0.031).Conclusions: Our findings confirm prior observations of age‐related DAT decline and suggest that this phenomenon is independent of changes in VMAT2. After the fifth decade of life, this reduction in DAT binding is associated with a motor performance comparable to mid‐adult life. These findings imply that biochemical processes associated with healthy aging may offset the naturaldecline in motor function observed in the elderly. Synapse 64:146–151, 2010. © 2009 Wiley‐Liss, Inc.
Feasibility of focused ultrasound therapy for recurrent cervicitis with high‐risk human papillomavirus infection
Authors: Li C.‐Z. , Wang Z.‐B. , Yang X. , Tang Y. , Wang D. , Huang Y. , Fan X.‐F.
Published: October 2009

Objective

To investigate the feasibility of focused ultrasound therapy for recurrent cervicitis with high‐risk human papillomavirus (HR‐HPV) infection.

Methods

This was a prospective clinical study, in which 20 patients with HR‐HPV‐positive recurrent cervicitis were enrolled. Focused ultrasound therapy was performed by one gynecologist. All patients were followed up for 6 months after ultrasound therapy. Telephone interviews, colposcopic examinations and Hybrid Capture II tests were performed to assess the safety and effectiveness of focused ultrasound therapy for HR‐HPV‐positive cervicitis.

Results

Ultrasound therapy was tolerated well, and no severe complications were observed in any patient. Vaginal discharge was found intermittently in 95% of patients. Without any intervention this disappeared 1 month after ultrasound therapy. Patients' symptoms were relieved significantly by ultrasound therapy, including 88.9% patients who had abundant leukorrhea, 80% who had pelvic pain and 87.5% who had postcoital bleeding. No colposcopic evidence of cervicitis remained postoperatively in 75% of patients, and cytological examination showed that the lesions had disappeared in 80% of patients. Follow‐up HPV testing revealed that 75% of patients presented negative HR‐HPV infection following treatment.

Conclusions

Focused ultrasound therapy is feasible and effective in the treatment of patients with HR‐HPV‐positive cervicitis. It may provide a useful non‐invasive treatment for recurrent cervicitis with HR‐HPV infection. Copyright © 2009 ISUOG. Published by John Wiley & Sons, Ltd.
Genetic Counselors’ Perceived Responsibilities Regarding Reproductive Issues for Patients at Risk for Huntington Disease
Authors: Hines Karrie A. , McCarthy Veach Patricia , LeRoy Bonnie S.
Published: October 2009

Research indicates that health care professionals’ attitudes may affect patients’ decisions regarding prenatal Huntington Disease testing, but few studies have sampled genetic counselors. In this qualitative study, genetic counselors described their experiences counseling individuals at risk for HD regarding reproductive decision‐making. Five major research questions were investigated: 1) What are genetic counselor responsibilities? 2) What issues arise for patients and counselors? 3) How do counselors reconcile prenatal testing with presymptomatic testing? 4) To what extent are counselors’ initial expectations of at‐risk patients’ beliefs and behaviors met? and 5) What advice would counselors offer to novice practitioners about working with this patient population? Fifteen genetic counselors experienced in counseling individuals at risk for HD participated in a semi‐structured phone interview that yielded several themes. For example, participants identified their primary responsibility asinformation provision; less prevalent werepsychosocial supportandfacilitating decision making. The most common ethical challenge was testing prenatally for HD which also results in presymptomatic testing of minors. Participants were divided about how directive to be in response to this ethical issue and about termination of a gene positive pregnancy.
Seasonal Variation of Chemical Composition and Antioxidant Activity of Essential Oil from Pistacia atlantica Desf. Leaves
Authors: Gourine Nadhir , Yousfi Mohamed , Bombarda Isabelle , Nadjemi Boubakeur , Gaydou Emile
Published: October 2009

The composition and antioxidant activities of Pistacia atlantica Desf. essential oil were investigated. Qualitative and quantitative differences in compositions and in antioxidant activities of male and female leaf essential oils were observed during the season. The essential oils obtained by hydrodistillation were analysed by GC and GC–MS. The oils were rich in monoterpenes hydrocarbons and oxygenated sesquiterpenes. The main components of male essential oil were α‐pinene/α‐thujene, spathulenol and bicyclogermacrene. The major component of female essential oil was δ‐3‐carene. The seasonal variation showed that most of the main components of the oils reached theirs highest values in September. The antioxidant activity of the oil was investigated in vitro using two assays: DPPH· (2,2‐di‐phenyl‐1‐picrylhydrazyl) free radical‐scavenging and FRAP (Ferric Reducing Antioxidant Power). The highest antioxidant capacity to scavenge free DPPH radicals was reached in the month of June for male oils and during the months of September–October for the female oils. The high reducing power for male oil was observed during the month of June and for the female oil it was in August. The female oil was more active than the male oil. The antioxidant capacity of the female oil was almost ten times higher than Ascorbic acid in the FRAP assay.
Dietary nitrate in man: friend or foe?
Authors: McKnight G. M. , Duncan C. W. , Leifert C. , Golden M. H.
Published: October 2009

Based on the premise that dietary nitrate is detrimental to human health, increasingly stringent regulations are being instituted to lower nitrate levels in food and water. Not only does this pose a financial challenge to water boards and a threat to vegetable production in Northern Europe, but also may be eliminating an important non-immune mechanism for host defence. Until recently nitrate was perceived as a purely harmful dietary component which causes infantile methaemoglobinaemia, carcinogenesis and possibly even teratogenesis. Epidemiological studies have failed to substantiate this. It has been shown that dietary nitrate undergoes enterosalivary circulation. It is recirculated in the blood, concentrated by the salivary glands, secreted in the saliva and reduced to nitrite by facultative Gram-positive anaerobes (Staphylococcus sciuriandS. intermedius) on the tongue. Salivary nitrite is swallowed into the acidic stomach where it is reduced to large quantities of NO and other oxides of N and, conceivably, also contributes to the formation of systemic S-nitrosothiols. NO and solutions of acidified nitrite, mimicking gastric conditions, have been shown to have antimicrobial activity against a wide range of organisms. In particular, acidified nitrite is bactericidal for a variety of gastrointestinal pathogens such asYersiniaandSalmonella.NO is known to have vasodilator properties and to modulate platelet function, as are S-nitrosothiols. Thus, nitrate in the diet, which determines reactive nitrogen oxide species production in the stomach (McKnightet al.1997), is emerging as an effective host defence against gastrointestinal pathogens, as a modulator of platelet activity and possibly even of gastrointestinal motility and microcirculation. Therefore dietary nitrate may have an important therapeutic role to play, not least in the immunocompromised and in refugees who are at particular risk of contracting gastroenteritides.
Low-dose folic acid supplementation does not influence plasma methionine concentrations in young non-pregnant women
Authors: Brouwerv Ingeborg A. , van Dusseldorp Marijke , Duran Marinus , Thomas Chris M. G. , Hautvast Joseph G. A. J. , Eskes Tom K. A. B. , Steegers-Theunissen Régine P. M.
Published: October 2009

An elevated plasma total homocysteine (tHcy) concentration is a risk factor for cardiovascular disease and for having offspring with a neural-tube defect. Folate is a methyl donor in the remethylation of homocysteine into methionine. Although folic acid supplementation decreases tHcy concentrations, effects of folic acid supplementation on plasma methionine concentrations are unclear. There is also concern that folic acid supplementation negatively affects vitamin B12status. We studied effects of low-dose folic acid supplementation on methionine and vitamin B12concentrations in plasma. We also investigated whether baseline plasma methionine and tHcy concentrations correlated with the baseline folate and vitamin B12status. For a period of 4 weeks, 144 young women received either 500 μg folic acid each day, or 500 μg folic acid and placebo tablets on alternate days, or a placebo tablet each day. Plasma methionine, tHcy and plasma vitamin B12concentrations were measured at start and end of the intervention period. Folic acid supplementation had no effect on plasma methionine or plasma vitamin B12concentrations although it significantly decreased tHcy concentrations. Plasma methionine concentrations showed no correlation with either tHcy concentrations (Spearmanrs- 0·01,P= 0·89), or any of the blood vitamin variables at baseline. Baseline tHcy concentrations showed a slight inverse correlation with baseline concentrations of plasma vitamin B12(rs- 0·25,P< 0·001), plasma folate (rs- 0·24,P< 0·01) and erythrocyte folate (rs- 0·19,P< 0·05). In conclusion, low-dose folic acid supplementation did not influence plasma methionine or plasma vitamin B12concentrations. Furthermore, no correlation between plasma methionine concentrations and the blood folate and vitamin B12status was shown.
Buoyancy-dominated displacement flows in near-horizontal channels: the viscous limit
Authors: TAGHAVI S. M. , SEON T. , MARTINEZ D. M. , FRIGAARD I. A.
Published: October 2009

We consider the viscous limit of a plane channel miscible displacement flow of two generalized Newtonian fluids when buoyancy is significant. The channel is inclined close to horizontal. A lubrication/thin-film approximation is used to simplify the governing equations and a semi-analytical solution is found for the flux functions. We show that there are no steady travelling wave solutions to the interface propagation equation. At short times the diffusive effects of the interface slope are dominant and there is a flow reversal, relative to the mean flow. We are able to find a short-time similarity solution governing this initial counter-current flow. At longer times the solution behaviour can be predicted from the associated hyperbolic problem (where diffusive effects are set to zero). Each solution consists of a number N ≥ 1 of steadily propagating fronts of differing speeds, joined together by segments of interface that are stretched between the fronts. Diffusive effects are always present in the propagating fronts. We explore the effects of viscosity ratio, inclinations and other rheological properties on the front height and front velocity. Depending on the competition of viscosity, buoyancy and other rheological effects, it is possible to have single or multiple fronts. More efficient displacements are generally obtained with a more viscous displacing fluid and modest improvements may also be gained with slight positive inclination in the direction of the density difference. Fluids that are considerably shear-thinning may be displaced at high efficiencies by more viscous fluids. Generally, a yield stress in the displacing fluid increases the displacement efficiency and yield stress in the displaced fluid decreases the displacement efficiency, eventually leading to completely static residual wall layers of displaced fluid. The maximal layer thickness of these static layers can be directly computed from a one-dimensional momentum balance and indicates the thickness of static layer found at long times.
Mechanisms underlying transient growth of planar perturbations in unbounded compressible shear flow
Authors: BAKAS NIKOLAOS A.
Published: October 2009

Non-modal mechanisms underlying transient growth of propagating acoustic waves and non-propagating vorticity perturbations in an unbounded compressible shear flow are investigated, making use of closed form solutions. Propagating acoustic waves amplify mainly due to two mechanisms: growth due to advection of streamwise velocity that is typically termed as the lift-up mechanism leading for large Mach numbers to an almost linear increase in streamwise velocity with time and growth due to the downgradient irrotational component of the Reynolds stress leading to linear growth of acoustic wave energy for large times. Synergy between these mechanisms along with the downgradient solenoidal component of the Reynolds stress produces large and robust energy amplification.

On the other hand, non-propagating vorticity perturbations amplify due to kinematic deformation of vorticity by the mean flow. For weakly compressible flows, an initial vorticity perturbation abruptly excites acoustic waves with exponentially small amplitude, and the energy gained by vorticity perturbations is transferred back to the mean flow. For moderate Mach numbers, a strong coupling between vorticity perturbations and acoustic waves is found with the energy gained by vorticity perturbations being transferred to acoustic waves that are abruptly excited by the vortex.

Calculation of the optimal perturbations for a viscous flow shows that for low Mach numbers, acoustic wave excitation by vorticity perturbations and the subsequent growth of acoustic waves leads to robust energy growth of the order of Reynolds number, while for large Mach numbers, synergy between the lift-up mechanism and the downgradient solenoidal component of the Reynolds stress dominates the growth and leads to a comparable large amplification of streamwise velocity.
Sentiments and Patriotism: The Indian National Army, General Elections and the Congress's Appropriation of the INA Legacy
Authors: KURACINA WILLIAM F.
Published: October 2009

This paper considers the extent to which Subhas Chandra Bose and the Indian National Army (INA) contributed to India's liberation from British imperialism. The fundamental issue examined is why leaders of the Indian National Congress appropriated the INA legacy, contrary to two decades of non-violent struggle and regardless of the incompatibility of Bose's ideology and strategic vision. Drawing on published sources that chart policy decisions and illustrate the attitudes of leading actors in the formulation of Congress policy, this paper hypothesizes that Congress leaders defended INA prisoners-of-war and questions why the Congress apparently abandoned its long-established principles for immediate political gains, only to re-prioritize anew India's national interests once the public excitement over the INA had quietened. It illustrates that the Congress's overt and zealous defence of the INA was intended to harness public opinion behind an all-India issue rooted in sentimentalism and patriotism. The paper concludes that such support was crucial to the Congress's post-war electioneering campaign and was designed to counter the Muslim League's equally emotive electoral messages.
Cambridge Spitsbergen Expedition, 1978
Authors: Pickton C. A. G. , Harland W. B.
Published: October 2009

The 1978 Cambridge Spitsbergen Expedition was organized along similar lines to those of previous years by C. A. G. Pickton and was in the field from late June to mid-August. Expedition members were: W. B. Harland (leader), C. A. G. Pickton, I. J. Fairchild, P. F. Rawson, M. J. Hambrey and P. Waddams (geologists); T. H. Druitt, J. H. Barne and D. A. Waldron (geological assistants); R. Davies (engineer); N. Cox and J. Caner (boat captains).
Transporting Arctic petroleum: a role for commercial submarines
Authors: McLaren Alfred. S.
Published: October 2009

Following a review of commercially-viable offshore oil deposits in northern Canada, Alaska and Greenland, the author explores alternative possibilities currently under consideration for transporting the oil to centres where it will be used.

Hazards of pipeline construction, particularly under water, and the problems and dangers associated with giant surface tankers and projected giant submarines are discussed. The author concludes that conventional submarines towing oil-filled plastic drogue tanks offer the safest and most expeditious method of solving the problem. This is the second of two articles (see Polar Record, 21 (133): 369–81 (1983)).
The changing role and significance of native peoples: In Canada's Northwest Territories
Authors: Wonders William C.
Published: October 2009

In Canada's Northwest Territories native peoples constitute the majority of the population, a unique situation which has recently had significant repercussions, national as well as regional, and will continue to do so in the foreseeable future. Native peoples are already playing an increasingly important role politically and economically in the Territories, currently illustrated by a proposed restructuring of the northern political map of Canada. Resolution of Comprehensive Land Claims with the Government of Canada will provide them with a major role in resource development and in policy governing it. At the time that many native peoples are entering into more active participation in modern society, renewed interest that others are showing in aspects of traditional culture creates at least a potential source of friction among them.
Antarctic Airways: Antarctica's first commercial airline
Authors: Swithinbank Charles
Published: October 2009

Antarctic Airways, an independent commercial airline, operated one DC-4 and two Twin Otter aircraft during the 1987–88 summer season. The DC-4 made twelve direct flights between Punta Arenas, Chile, and the Ellsworth Mountains. The Twin Otters were used for onward flights to destinations including the South Pole. The significance of this development is that scientists from countries that do not have ships or bases in the Antarctic can now work on the continent without either.
A study of sea ice in the Sea of Okhotsk with SAR data
Authors: Wakabayashi Hiroyuki , Hirano Kazuyoshi , Nishio Fumihiko , Aota Masaaki , Takahashi Shuhei
Published: October 2009

The ‘Okhotsk Sea Ice Observation Experiment’ 93' was carried out in February 1993 in the southern part of the Sea of Okhotsk and in Lake Saroma, Japan. The aim of the experiment was to investigate how effectively Synthetic Aperture Radar (SAR) can monitor sea ice in this region. Satellite data from JERS-1/SAR (J-SAR), ERS-1/SAR CESAR), and SPOT-2/HRV, as well as data from airborne sensors and ground-truth data, were utilized. From the overall analysis of those data, several results were obtained. First, the range of backscatter of the ice cover on Lake Saroma was determined, as well as a relation between ice type and backscatter. Second, a method for making SAR mosaic images was developed to monitor sea ice over a wide area. When comparing J-SAR(L-band) data with E-SAR(C-band) data acquired simultaneously over the same area, J-SAR proved to be superior to E-SAR in showing the existence of sea ice. And third, it was confirmed that the backscatter of E-SAR was correlated to the ice thickness, which may be explained by the relation between the backscatter and the ice-surface temperature.
Eider exploitation by hunters and trappers on Svalbard during the 19th and early 20th centuries
Authors: Rossnes Gustav
Published: October 2009

Natural resources of Svalbard, notably seal, walrus, whale, reindeer, polar bear and Arctic fox, were exploited through the 19th and early 20th centuries by both overwintering and seasonal hunters and trappers. Hunters also collected eggs and down of eider ducks to supplement their catches. Amounts of uncleaned down officially registered as imported to Norway ranged from 300–2600 kg annually (mean 1300 kg). The accuracy of these figures is discussed. Eider down accounted for 7–10% of the annual income of the trappers who wintered on the islands. Competition between trappers spending the winter and the crews of the sealers and whalers often resulted in an unorganized free-for-all collection of down and eggs, causing a steady decline of the eider population. The population was protected by legislation in 1963 and the designation of several bird sanctuaries in 1973, in which it was hoped that eider numbers would recover. It is not clear whether these measures have been successful: historical records have too many lacunae for a reliable calculation of the original size of the eider population which the trappers and sealers exploited.
An evangelical Christian on Franklin's last expedition: Lieutenant John Irving of HMSTerror
Authors: Lloyd-Jones Ralph
Published: October 2009

This brief analysis of the life and personal outlook of one of the officers on Sir John Franklin's Northwest Passage expedition (1845–1848) begins a long-overdue process of reconstructing the background, attitudes, and motivation of those serving onErebusandTerror. A great deal of recent research and speculation has considered the reasons behind the failures of Franklin's last expedition, but, although forensic science may prove useful in helping to discover what happened to Captain Crozier and his companions, it is equally important to understand those men's beliefs while they lived. This article looks at the career and religious background of John Irving, the Third Officer of HMSTerror.
Laboratory simulation of thermal erosion: possible application to pollution problems
Authors: Makhloufi N. , Costard F. , Puente J. Aguirre , Costard J. , Cano R. Posado , Guillemet G.
Published: October 2009

In the Arctic, thermal erosion results from ground thawing produced by heat transfer when water is flowing upon the frozen ground. A mathematical model has been proposed to determine the efficiency of the process and the rate of thermal erosion. Considering a constant heat-transfer coefficient, the resulting thermal flux at the groundsurface produces ground thaw, and the unfrozen sediments can be removed by the water flow. A particular case of an ablation model consists of an immediate removing of sediments by a strong flow and by the action of gravity. An experimental hydraulic device was built to test the authors' theoretical ablation model, describing a fluvial thermalerosionprocess. The effect of different parameters (Reynolds number, water temperature, ground-ice temperature) on the rate of thermal erosion for samples of frozen sand was investigated. Results from the experiments are in agreement with theoretical estimates using the mathematical model. Moreover, this study shows a hierarchy of parameters in terms of efficiency of the fluvial thermal-erosion process.

A discussion of the possible effects of the contaminants on the erosion rate leads the authors to propose two kinds of experiments: a contaminated frozen sample eroded by a water flow, varying in this case the thermophysical properties of the sample (density, specific heat capacity, a latent heat, and change of phase), and an experiment consisting of erosion of a frozen sample by contaminated flow. This second case is also complex due to many mechanical, hydrodynamic and thermal interactions at the ground surface. This paper reports results of thermal erosionfrom experiments with icesaturated sand. A pure ice sample is used to determine the heat-transfer coefficient.
Hydrology of Tierney Creek, Vestfold Hills, Antarctica
Authors: Bronge Christian
Published: October 2009

The discharge in Tierney Creek from proglacial Chelnok Lake was recorded during the summer of 1987–1988. In addition, air temperature, water temperature, and radiation were recorded. Multiple linear regressions revealed that discharge could be predicted from recorded radiation and air temperature in late summer. In early summer, other factors such as wind must also be taken into account. Long-term discharge fluctuations displayed response times that decreased during the runoff season due to the opening of the meltwater channels on the ice-margin. During parts of the runoff season, flow variations were modulated by nocturnal freezing in the creek, a phenomenon still more pronounced in Onyx River in the Dry Valleys of Victoria Land. Hydrologically, Tierney Creek resembled Onyx River, but, in the Onyx, the flow pattern was more exclusively determined by low air temperatures than it was in Tierney Creek. In the Dry Valleys, streams whose lengths, gradients, and discharges are of the same magnitude as those of Tierney Creek, also display similar recession coefficients and time lags between flow peak and insolation peak.