bluuebunny/crossref_metadata_2025 huggingface dataset:
Ultrathin Carbon Film Electrodes from Vacuum‐Carbonised Cellulose Nanofibril Composite
Authors: Vuorema Anne , Sillanpää Mika , Rassaei Liza , Wasbrough Matthew J. , Edler Karen J. , Thielemans Wim , Dale Sara E. C. , Bending Simon , Wolverson Daniel , Marken Frank
Published: February 2010

A novel way to produce ultrathin transparent carbon layers on tin‐doped indium oxide (ITO) substrates is developed. The ITO surface is coated with cellulose nanofibrils (from sisal) via layer‐by‐layer electrostatic binding with poly(diallyldimethylammonium chloride) or PDDAC acting as the binder. The cellulose nanofibril‐PDDAC composite film is then vacuum‐carbonised at 500 °C. The resulting carbon films are characterised by atomic force microscopy (AFM), small angle X‐ray scattering (SAXS), wide‐angle X‐ray scattering (WAXS), and Raman methods. Smooth carbon films with good adhesion to the ITO substrate are formed. The electrochemical characterisation of the carbon films is based on the oxidation of hydroquinone and the reduction of benzoquinone in aqueous phosphate buffer media. A modest effect of the cellulose nanofibril‐PDDAC film on the rate of electron transfer is observed. The effect of the film on the rate of electron transfer after carbonisation is more dramatic. For a 40‐layer cellulose nanofibril‐PDDAC film after carbonisation a two‐order of magnitude change in the rate of electron transfer occurs presumably due to a better interaction of the hydroquinone/benzoquinone system with the electrode surface.
Preparation of open tubular molecule imprinted polymer capillary columns with various templates by a generalized procedure and their chiral and non‐chiral separation performance in CEC
Authors: Zaidi Shabi Abbas , Han Kyoung Moon , Hwang Dong Guk , Cheong Won Jo
Published: February 2010

A generalized preparation procedure of open tubular (OT) molecule imprinted polymer (MIP) columns is proposed for a number of templates with acidic functionality such as profen drugs and others. The template (S‐enantiomer) was mixed with methacrylic acid, ethylene glycol dimethacrylate and 4‐styrenesulfonic acid, dissolved in a porogen mixture of ACN/2‐propanol (9/1), and incubated in a pretreated and silanized fused silica capillary by the thermal non‐covalent polymerization procedure. The whole preparation procedure was exactly the same for all the MIP capillaries except for the selection of template. Nevertheless, the morphologies of the MIP layers were markedly variant depending upon the choice of template. The separation efficiency of each OT‐MIP column for chiral separation of R‐ and S‐enantiomers was examined and tuned to obtain the best separation efficiency by changing the chromatographic parameters such as eluent composition and pH. Different optimized conditions were obtained for different OT‐MIP columns. Nevertheless, a unified eluent could be used to obtain still quite satisfactory results. Non‐chiral separation of the MIP columns were also examined in the unified eluent with two sets of test mixtures, that is, a mixture of alkylbenzenes and a mixture of small polar solutes. The chiral and non‐chiral separation of this study resulted in very good separation efficiencies. This work is the very first study for the generalization of preparation of OT‐MIP columns for a number of templates.
Change‐point analysis of mean annual rainfall data from Tucumán, Argentina
Authors: Jandhyala Venkata K. , Fotopoulos Stergios B. , You Jing
Published: February 2010

The annual mean rainfall data from Tucumán, Argentina for the years 1884–1996 is revisited for an in‐depth change‐point analysis. Applying classical change detection statistics, we first demonstrate that change‐point analysis under independence is invalid. Upon properly adjusting for dependence, it is found that a significant change has occurred in the mean of the data in and around 1956. The data analysis demonstrates that change detection statistics are sensitive to how the model variance is estimated. Moreover, the analysis shows that even marginally significant serial correlations among the observations can have a highly significant effect upon the variance estimate. Finally, the analysis illustrates that one should exercise care while implementing parametric or non‐parametric methods in estimating the model variance, and one should be prepared for one of the methods outperforming the other. Copyright © 2010 John Wiley & Sons, Ltd.
Chemokine expression in the white matter spinal cord precursor niche after force‐defined spinal cord contusion injuries in adult rats
Authors: Knerlich‐Lukoschus Friederike , von der Ropp‐Brenner Beata , Lucius Ralph , Mehdorn Hubertus Maximilian , Held‐Feindt Janka
Published: February 2010

Inflammatory cascades induced by spinal cord injuries (SCI) are localized in the white matter, a recognized neural stem‐ and progenitor‐cell (NSPC) niche of the adult spinal cord. Chemokines, as integrators of these processes, might also be important determinants of this NSPC niche. CCL3/CCR1, CCL2/CCR2, and SDF‐1α/CXCR4 were analyzed in the ventrolateral white matter after force defined thoracic SCI: Immunoreactivity (IR) density levels were measured 2 d, 7 d, 14 d, and 42 d on cervical (C 5), thoracic (T 5), and lumbar (L 5) levels. On day post operation (DPO) 42, chemokine inductions were further evaluated by real‐time RT‐PCR and Western blot analyses. Cellular phenotypes were confirmed by double labeling with markers for major cell types and NSPCs (nestin, Musashi‐1, NG2, 3CB2, BLBP). Mitotic profiles were investigated in parallel by BrdU labeling. After lesion, chemokines were induced in the ventrolateral white matter on IR‐, mRNA‐, and protein‐level. IR was generally more pronounced after severe lesions, with soaring increases of CCL2/CCR2 and continuous elevations of CCL3/CCR1. SDF‐1α and CXCR4 IR induction was focused on thoracic levels. Chemokines/‐receptors were co‐expressed with astroglial, oligodendroglial markers, nestin, 3CB2 and BLBP by cells morphologically resembling radial glia on DPO 7 to DPO 42, and NG2 or Musashi‐1 on DPO 2 and 7. In the white matter BrdU positive cells were significantly elevated after lesion compared with sham controls on all investigated time points peaking in the early time course on thoracic level: Here, chemokines were co‐expressed by subsets of BrdU‐labeled cells. These findings suggest an important role of chemokines/‐receptors in the subpial white matter NSPC niche after SCI. © 2010 Wiley‐Liss, Inc.
Association of the glucocorticoid receptor with STAT3, C/EBPβ, and the hormone‐responsive element within the rat haptoglobin gene promoter during the acute phase response
Authors: Arambašić Jelena , Poznanović Goran , Ivanović‐Matić Svetlana , Bogojević Desanka , Mihailović Mirjana , Uskoković Aleksandra , Grigorov Ilijana
Published: February 2010

Upregulation of haptoglobin (Hp) expression in the rat during the acute phase (AP) response is the result of synergistic effects of IL‐6–, IL‐1β–, and corticosterone‐activated signaling pathways. IL‐6 signaling terminates in cis–trans interactions of the Hp gene hormone‐responsive element (HRE) with transcription factors STAT3 and C/EBPβ. The aim of this study was to examine the unresolved molecular mechanism of glucocorticoid action. A 3‐fold rise in serum corticosterone at 2 and 4 h of the AP response induced by turpentine administration preceded a 2.3‐fold increase in the rate of Hp gene transcription at 12 h that was accompanied by a 4.8‐fold increase in glucocorticoid receptor (GR), the appearance of an 86‐kDa STAT3 isoform and 3.9‐, 1.9‐, and 1.7‐fold increased amounts of 91‐kDa STAT3, 35‐ and 42‐kDa C/EBPβ isoforms in the nucleus. These events resulted in 4.6‐ and 2.5‐fold increased Hp levels in the liver and serum at 24 h. HRE affinity chromatography and immunoblot analysis revealed that maximal occupancy of the HRE with GR, STAT3, and C/EBPβ at 12 h correlated with increased transcriptional activity of the Hp gene. Coimmunoprecipitation experiments showed that activated GR established de novo interaction with STAT3 isoforms while GR–C/EBPβ interactions observed during basal transcription increased during the AP response. Computer analysis of the HRE disclosed two potential GR‐binding sites: one overlapping STAT3, another adjacent to a C/EBPβ‐binding site. This finding and the experimental results suggest that activated GR through direct interactions with STAT3 and C/EBPβ, participates in Hp gene upregulation as a transcriptional coactivator. © 2010 IUBMB IUBMB Life, 62(2): 227–236, 2010
Climatic implications of cirque distribution in the Romanian Carpathians: palaeowind directions during glacial periods
Authors: Mîndrescu Marcel , Evans Ian S. , Cox Nicholas J.
Published: February 2010

The many glacial cirques in the mountains of Romania indicate the distribution of former glacier sources, related to former climates as well as to topography. In the Transylvanian Alps (Southern Carpathians) cirque floors rise eastward at 0.714 m km−1, and cirque aspects tend ENE, confirming the importance of winds from some westerly direction. There is a contrast between two neighbouring ranges: the Făgăraş, where the favoured aspect of cirques is ENE, and the Iezer, where the tendency is stronger and to NNE. This can be explained by the Iezer Mountains being sheltered by the Făgăraş, which implies precipitation‐bearing winds from north of west at times of mountain glaciation. Palaeoglaciation levels also suggest winds from north of west, which is consistent with aeolian evidence from Pleistocene dunes, yardangs and loess features in the plains of Hungary and southwestern Romania. In northern Romania (including Ukrainian Maramureş) the influence of west winds was important, but sufficient only to give a northeastward tendency in cirque aspects. This gave stronger asymmetry than in the Transylvanian Alps, as the northward (solar radiation incidence) tendency in these marginally glaciated mountains was less diluted by wind effects. Cirque floors in northern Romania are lower also in northeast‐facing cirques. In general, cirque aspects result from several factors and the mean tendency is not downwind, but is displaced from poleward by wind and by minor effects. Copyright © 2010 John Wiley & Sons, Ltd.
Determination of aminoglycoside and macrolide antibiotics in meat by pressurized liquid extraction and LC‐ESI‐MS
Authors: Berrada Houda , Moltó Juan C. , Mañes Jordi , Font Guillermina
Published: February 2010

A simple method for the simultaneous determination of dihydrostreptomycin, spectinomycin, spiramycin, streptomycin, tilmicosin, and tylosin in meat has been developed using pressurized liquid extraction and LC‐triple quadrupole MS (LC‐ESI‐MS/MS). The pressurized liquid extraction operational parameters were optimized and no protein precipitating and fat removing steps were required. A gradient HPLC separation was developed with ion‐pair mobile phases consisting of aqueous 1 mM heptafluorobutyric acid water and methanol. Protonated molecules were used as precursor ions for CID. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of three fragment ion transitions to provide a high degree of sensitivity and specificity. Dirithromycin and sisomycin were selected as internal standards. A validation study was conducted for these antibiotics in poultry meat samples. All selected compounds could be detected (monitoring ions by multiple reaction monitoring) in meat samples at amounts below the regulatory level of concern. Using the internal standards, pressurized liquid extraction recovery rates were from 70 to 96% (RSD 12–25%). LC‐ESI‐MS/MS method detection limits of the selected antibiotics were 1–6 μg/kg. Good method reproducibility was found by intra‐ and inter‐day precisions at maximum residue level, yielding the RSDs less than 15 and 16%, respectively.
Recent advances in application of hydrophilic interaction chromatography for quantitative bioanalysis
Authors: Jian Wenying , Edom Richard W. , Xu Yaodong , Weng Naidong
Published: February 2010

Hydrophilic interaction chromatography (HILIC) provides a complementary separation mode to RPLC and thus has been gaining increased utilization in LC‐MS/MS based quantitative bioanalysis. It has proven to be a powerful tool for separation of polar compounds and has afforded increased selectivity, higher sensitivity, and improved efficiency for quantitation of drug and their metabolites in complex biological matrices. Practical knowledge has been gained for some of the challenges with HILIC applications and effective remedies have been adopted to overcome these challenges. Due to its orthogonality to RPLC, HILIC has been coupled with RP sample preparation or separation techniques, either off‐line or on‐line to achieve better assay selectivity. The low back‐pressure with HILIC enables fast separations under higher flow rates. Small particle columns can be operated under HILIC conditions with regular system back‐pressure, eliminating the requirement for ultra‐high‐pressure liquid chromatographic systems. Matrix effects under HILIC have also been systematically investigated. Effective approaches to reduce or eliminate matrix effects have included optimizing sample preparation, modifying chromatographic conditions, and/or using valve‐switching techniques. Finally, the utilization of HILIC is not limited to quantitation of polar drugs and their metabolites, but extended to quantitaiton of relatively non‐polar compounds, peptides and biomarkers.
Lactic acid quantitation in hand dishwashing liquid using an HILIC‐UV methodology
Authors: Storton Mark , Exarchakis James , Waters Tracy , Hao Zhigang , Parker Barry , Knapp Michael
Published: February 2010

Different hydrophilic interaction chromatography (HILIC) columns were screened for lactic acid separation in hand dishwashing liquid products and the influence of mobile phase strength, buffer concentration and column temperature on the retention of lactic acid on a Zorbax NH2 column was investigated. An isocratic HILIC method for the quantitation of lactic acid in hand dishwashing liquid products was developed. The mobile phase consists of 70% methanol and 30% 20 mM sodium phosphate buffer (v/v) at pH 2.5. The HILIC stationary phase is Zorbax NH2, 250×4.6 with a 5 μm particle size. Detection was carried out using a variable wavelength UV‐VIS detector at 226 nm. The linear range and percent recovery for lactic acid in the products were 44.68–1206.39 μg/mL and 100.3%, respectively. This paper provides an optimized HILIC methodology for the analysis of an acidic polar analyte (lactic acid) on a basic stationary phase. The proposed method can be used for the routine analysis of lactic acid.
Single‐pump bi‐dimensional LC applied to the characterization of derivatized fatty alcohol ethoxylates
Authors: Micó‐Tormos Anna , Simó‐Alfonso Ernesto F. , Ramis‐Ramos Guillermo
Published: February 2010

A column selection valve and a 6‐port 2‐position injection valve were combined to implement bi‐dimensional LC in a system driven by a single pump. The system was applied to the separation of linear fatty alcohol ethoxylates with 12–18 carbon atoms in the hydrocarbon moiety, previous derivatization with diphenic anhydride. Separation on the first separation dimension (C1) was carried out with a propyl‐diol column and an acetonitrile/aqueous ammonium acetate gradient. Fatty alcohol ethoxylate hydrocarbon series (oligomers with the same number of carbon atoms in the alkyl chain but differing in the number of ethylene oxide units) were resolved without distinguishing the oligomers within the series. Selected segments of the eluate of C1were transferred to the second column (C2), where the successive oligomers within the isolated series were resolved by using either an octyl‐silica or a pentafluoro‐phenyl‐propyl column and an acetonitrile/water gradient. Flow stopping at C1during system re‐conditioning and elution along the second dimension did not produce any noticeable band broadening. Overlapping of the non‐ethoxylated and mono‐ethoxylated oligomers with other oligomers within the series was avoided by eluting the pentafluoro‐phenyl‐propyl column at low temperatures (3°C).
Determination of multicomponent contents in Calculus bovis by ultra‐performance liquid chromatography–evaporative light scattering detection and its application for quality control
Authors: Kong Weijun , Jin Cheng , Xiao Xiaohe , Zhao Yanling , Liu Wei , Li Zulun , Zhang Ping
Published: February 2010

A fast ultra‐performance liquid chromatography–evaporative light scattering detection (UPLC‐ELSD) method was established for simultaneous quantification of seven components in natural Calculus bovis (C. bovis) and its substitutes or spurious breeds. On a Waters Acquity UPLC® BEH C18 column, seven analytes were efficiently separated using 0.2% aqueous formic acid–acetonitrile as the mobile phase in a gradient program. The evaporator tube temperature of ELSD was set at 100°C with the nebulizing gas flow‐rate of 1.9 L/min. The results showed that this established UPLC‐ELSD method was validated to be sensitive, precise and accurate with the LODs of seven analytes at 2–11 ng, and the overall intra‐day and inter‐day variations less than 3.0%. The recovery of the method was in the range of 97.8–101.6%, with RSD less than 3.0%. Further results of PCA on the contents of seven investigated analytes suggested that compounds of cholic acid, deoxycholic acid and chenodeoxycholic acid or cholesterol should be added as chemical markers to UPLC analysis of C. bovis samples for quality control and to discriminate natural C. bovis sample and its substitutes or some spurious breeds, then normalize the use of natural C. bovis and ensure its clinical efficacy.
Hydroxychloroquine for subglottic stenosis: A novel therapy in the battle for air
Authors: Hirshoren Nir , Eliashar Ron , Weinberger Jeffrey M.
Published: February 2010

Upper airway obstruction due to subglottic edema and granulation tissue proliferation may cause severe morbidity and may be life threatening. Hydroxychloroquine interferes with antigen processing by means of raising lysosomal pH and immune response modulation. Herein, we present the outcome of a steroid‐sparing treatment using hydroxychloroquine in an 80‐year‐old man with acquired subglottic stenosis and steroid dependency. Twice daily oral hydroxychloroquine at 2 mg/kg/day allowed cessation of systemic steroids without recurrence of the stenosis. Successful weaning of the hydroxychloroquine took place over a 5‐month period. Laryngoscope, 2010
Evaluation of velopharyngeal function after relocation pharyngoplasty for obstructive sleep apnea
Authors: Li Hsueh‐Yu , Lee Li‐Ang , Fang Tuan‐Jen , Lin Wan‐Ni , Lin Wen‐Ying
Published: February 2010

Objectives/Hypothesis:

To assess if relocation pharyngoplasty (RP) causes velopharyngeal dysfunction in patients with obstructive sleep apnea (OSA) by evaluating perioperative nasalance, nasality, voice, and articulation.

Study Design:

Prospective, comparative study.

Methods:

Twenty‐four OSA patients selected for RP (two women and 22 men; mean age, 35 years) were enrolled for the study of velopharyngeal function in speech. The RP procedure involved removal of supratonsillar adipose tissue, preservation of all palatal muscular structure, splinting the lateral pharyngeal wall, and anterior advancing of the soft palate. Measurements of nasalance (vowel /a/, /i/, consonant /m/, oronasal, oral, and nasal texts), nasality (mirror‐fogging test, degree of nasality, Gutzmann test and Bzoch hypernasality test), voice (acoustic analysis), and articulation (velar sound) were taken before RP and 3 months after the procedure and compared.

Results:

Comparative analysis of clinical measures showed that no significant differences were found following RP in nasalance (except for the vowel /a/), nasality, articulation, and voice. The only difference with regard to vowel /a/ showed, instead of an increase, a significant decrease of nasalance from 17.3 ± 10.8 to 11.3 ± 6.7 (P = .004), which may be attributed to the advancing and lifting of the soft palate in RP, leading to relaxation of the levator veli palatine and uvular muscles, which facilitates their contraction in velopharyngeal closure during particular vowel phonation.

Conclusions:

RP for OSA does not cause velopharyngeal insufficiency in terms of voice, nasality, and articulation in spite of anterior advancement of the soft palate, but does induce a nondetrimental change in nasalance. Laryngoscope, 2010
Reduction‐Sensitive Self‐Aggregates as a Novel Delivery System
Authors: Kim Ju Eun , Cha Eui‐Joon , Ahn Cheol‐Hee
Published: February 2010

Methoxy PEG amine with molecular weight of 5k and ε‐caprolactone with molecular weight of 1 960 were conjugated to a peptide comprising three cysteine residues. The shift of peak molecular weight and narrow molecular weight distribution in GPC trace without any noticeable shoulder as well as 1H NMR analysis confirmed the successful synthesis of the copolymer. A modified O/W dialysis system was employed to prepare self‐aggregates having the size around 210 nm. During the dialysis, stabilized aggregates were obtained by intermolecular disulfide bonds via oxidation. Critical aggregate concentration (CAC) of the copolymer was determined as 0.07 mg · mL−1 and disulfide‐stabilized self‐aggregates remained stable regardless of the concentration without displaying CAC. Doxorubicin‐loading amount and efficiency was 8.7 and 26.0%, respectively. Release profile of doxorubicin below CAC at 37 °C showed a sustained release and the addition of D,L‐dithiothreitol (DTT) after 24 h triggered a burst release of doxorubicin. Intermolecular disulfide bonds via oxidation stabilized the polymeric aggregates even in the diluted condition similar to that in the bloodstream and addition of DTT destabilized the aggregates to burst encapsulated doxorubicin in the reductive condition.

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Highly Ordered Hexagonal Arrays of Hybridized Micelles from Bimodal Self‐Assemblies of Diblock Copolymer Micelles
Authors: Yoo Seong Il , Yun Sang Hyun , Kim Hyeong Ki , Sohn Byeong‐Hyeok
Published: February 2010

We demonstrate the formation of highly ordered hexagonal arrays of hybridized polystyrene–poly(4‐vinyl pyridine), PS–PVP, micelles with controllable size by solvent annealing techniques. Because the formation of hybridized micelles was prohibited in the mixture solutions of two different‐sized PS–PVP micelles, single‐layered films with bimodal self‐assemblies of small and large micelles were fabricated from the mixture solutions by adjusting their mixing ratios. When the single‐layered films were solvent annealed by saturated vapor of tetrahydrofuran (THF), on the other hand, small and large PS–PVP micelles in the bimodal self‐assemblies merged together to form hybridized micelles. In addition, the hybridized micelles arranged themselves in a highly ordered hexagonal array, the diameter and center‐to‐center distance of which were precisely adjusted by varying the mixing ratio of small to large micelles in the bimodal assemblies.

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Chromophoric Barbituric Acid Derivatives with Adjustable Hydrogen‐Bonding Patterns as Component for Supramolecular Structures
Authors: Bolz Ina , Bauer Mirko , Rollberg Anja , Spange Stefan
Published: February 2010

Summary: The barbituric acid moiety of the presented dyes shows multifunctional properties like acidochromism, solvatochromism, and adjustable hydrogen‐bonding pattern for molecular recognition. Hydrogen‐bonding ability, acidity and solvatochromic effects are studied for a series of N‐alkyl substituted 5‐(4‐nitrophenyl)‐barbiturates. Solvatochromism and metal ion complexation are also investigated using chromophoric thiobarbituric acid derivatives.
Nano‐Encapsulation of Proteins Via Self‐Assembly with Lipids and Polymers
Authors: Dalla‐Bona Alexandra , Primbs Jacqueline , Angelova Angelina
Published: February 2010

Summary: The solubilization and encapsulation of the weakly soluble protein hemoglobin was investigated at the nanoscale using self‐assembly with the branched polymer polyethyleneimine (PEI), the lipid glycerol monooleate (GMO), and two amphiphilic poly(ethylenglycol) monooleate derivatives with molecular weights 2100 g/mol (MO‐PEG1) and 860 g/mol (MO‐PEG2). The created self‐assembly nanovehicles were analyzed by quasi‐elastic light scattering (QELS) in order to determine their sizes as well as by circular dichroism in order to characterize the protein presence in the nanoobjects. The cationic polymer PEI formed mixed nano‐objects with the protein hemoglobin. The polymer conformation in the nanovehicle was established to be sensitive to dilution, a property that can be essential for the protein release upon administration. The amphiphile MO‐PEG1 was a co‐surfactant in the dispersion of monoglyceride lipid nanoobjects needed for the hemoglobin encapsulation. The amphiphile MO‐PEG2 formed small micelles in the absence of a lipid. The nanoobjects dispersions were studied for their stability on storage and reproducibility.
Rotaxanes and Catenanes Derived from Tetra‐Urea Calix[4]arenes
Authors: Böhmer Volker , Rudzevich Yuliya , Rudzevich Valentyn
Published: February 2010

Summary: Calix[4]arenes, substituted by four urea groups at their wide rim, form dimeric capsules in apolar solvents, which are held together by a seam of intermolecular hydrogen bonds. The heterodimerisation of tetra‐aryl and tetratosyl ureas was used to synthesize various derivatives, in which adjacent urea residues are connected to form two, three or four loops. The aliphatic connections were tied by olefin metathesis between adjacent alkenyl residues followed by hydrogenation. Heterodimers of tetra‐alkenyl substituted tetra‐ureas and bis‐ or tetraloop derivatives were converted analogously to multiple catenanes. Tetra[2]rotaxanes were obtained in a similar manner. In addition to the spectroscopic evidence (NMR, MS) several compounds were confirmed by crystal structures.
Unexpected Interactions of an Alternating Poly(ether‐ester) with Artificial and Biological Bilipidic Membranes
Authors: Illy Nicolas , Bacri Laurent , Wojno Justyna , Destouches Damien , Brissault Blandine , Courty José , Auvray Loïc , Penelle Jacques , Barbier Valessa
Published: February 2010

Summary: The anionic polymerization of a spiro monomer containing both an ester‐activated cyclopropane moiety and a 1,4,7,10,13‐pentaoxacyclohexadecane‐14,16‐dione crown ether bislactone unexpectedly yielded a linear alternating poly(ether‐ester) via the ring‐opening polymerization of the crown ether cycle. Ion conductivity measurements using black lipid membranes as model systems showed that oligomers of this structure are able to permeabilize bilipidic membranes, with single‐ion channel behaviors being observed. Biological assays on fibroblast cells indicated a significant cytotoxicity, probably related to the above permeabilization mechanism.
Polymeric Monolithic Media: Synthesis, Pore Size Selective Functionalization and Applications
Authors: Buchmeiser M. R. , Bandari R. , Prager‐Duschke A. , Löber A. , Knolle W.
Published: February 2010

Summary: This contribution will briefly summarize the latest developments in ring‐opening metathesis polymerization (ROMP) and electron beam‐triggered free radical polymerization derived monolithic supports. Issues relevant to separation science and heterogeneous catalysis will be addressed.
Pore Modification in Porous Ceramic Membranes With Sol‐Gel Process and Determination of Gas Permeability and Selectivity
Authors: Tüzün F. Nihal , Arçevik Ersel
Published: February 2010

Summary: The aim of the study was to investigate the variation in total surface area, porosity, pore size, Knudsen and surface diffusion coefficients, gas permeability and selectivity before and after the application of sol‐gel process to porous ceramic membrane in order to determine the effect of pore modification. In this study, three different sol‐gel process were applied to the ceramic support separately; one was the silica sol‐gel process which was applied to increase porosity, others were silica‐sol dip coating and silica‐sol processing methods which were applied to decrease pore size. As a result of this, total surface area, pore size and porosity of ceramic support and membranes were determined by using BET instrument. In addition to this, Knudsen and surface diffusion coefficients were also calculated. After then, ceramic support and membranes were exposed to gas permeation experiments by using the CO2 gas with different flow rates. Gas permeability and selectivity of those membranes were measured according to the data obtained. Thus, pore surface area, porosity, pore size and Knudsen diffusion coefficient of membrane treated with silica sol‐gel process increased while total surface area was decreasing. Therefore, permeability of ceramic support and membrane treated with silica sol‐gel process increased, and selectivity decreased with increasing the gas flow rate. Also, surface area, porosity, pore size, permeability, selectivity, Knudsen and surface diffusion coefficients of membranes treated with silica‐sol dip coating and silica‐sol processing methods were determined. As a result of this, porosity, pore size, Knudsen and surface diffusion coefficients decreased, total surface area increased in both methods. However, viscous flow and Knudsen flow permeability were detected as a consequence of gas permeability test and Knudsen flow was found to be a dominant transport mechanism in addition to surface diffusive flow owing to the small pore diameter in both methods. It was observed that silica‐sol processing method had lower pore diameter and higher surface diffusion coefficient than silica‐sol dip coating method.
TiO2‐Functionalized Sulphur Containing Polyimides for Optical Applications
Authors: Mrsevic M. , Staudt C.
Published: February 2010

Summary: Novel sulphur‐containing 6FDA‐SDA‐DABA (4,4'‐(hexafluoroisopropylidene)diphthalic anhydride – 4,4'‐diaminodiphenylether – 3,5‐diaminobenzoic acid) copolyimides have been synthesized to create a polymer basis for the use as optical polymers, capable of implementing TiO2 nanoparticles by simple mixing or covalent bonding of functionalized nanoparticles. First fine dispersed nanoparticle‐composites were made by simple mixing of rutile‐type TiO2 nanoparticles and the synthesized copolyimides. Moisture‐absorption was measured in a climate‐cabinet, transparency and cutoff wavelengths have been determined by UV‐VIS spectra. The homogeneity of the composites was verified by scanning electron microscope (SEM) images of the cross sections. The polyimides show constantly low water sorption below 0.08 wt% and cutoff wavelengths below 440 nm. The implementation of nanoparticles by simple mixing was verified by SEM.
Evolution of Fiber Morphologies during Poly (acrylonitrile) Electrospinning
Authors: Fang Jian , Wang Hongxia , Niu Haitao , Lin Tong , Wang Xungai
Published: February 2010

Summary: In this study, we used a facile approach to examine the evolution of fiber morphologies during electrospinning, via solidifying the newly electrospun polyacrylonitrile (PAN) nanofibers in an ethanol bath at different electrospinning distances (2 cm to 10 cm). It has been observed that a massive jet‐thinning took place at the initial stage of whipping instability, followed by uneven fiber‐stretching. The fiber‐stretching at the later whipping stage was mainly concentrated on beaded fiber sections, which improved the uniformity of the resultant fibers.
The accuracy of Doppler radar wind retrievals using insects as targets
Authors: Rennie S. J. , Illingworth A. J. , Dance S. L. , Ballard S. P.
Published: February 2010

Insect returns from the UK's Doppler weather radars were collected in the summers of 2007 and 2008, to ascertain their usefulness in providing information about boundary layer winds. Such observations could be assimilated into numerical weather prediction models to improve forecasts of convective showers before precipitation begins. Significant numbers of insect returns were observed during daylight hours on a number of days through this period, when they were detected at up to 30 km range from the radars, and up to 2 km above sea level. The range of detectable insect returns was found to vary with time of year and temperature. There was also a very weak correlation with wind speed and direction. Use of a dual‐polarized radar revealed that the insects did not orient themselves at random, but showed distinct evidence of common orientation on several days, sometimes at an angle to their direction of travel. Observation minus model background residuals of wind profiles showed greater bias and standard deviation than that of other wind measurement types, which may be due to the insects' headings/airspeeds and to imperfect data extraction. The method used here, similar to the Met Office's procedure for extracting precipitation returns, requires further development as clutter contamination remained one of the largest error contributors. Wind observations derived from the insect returns would then be useful for data assimilation applications. Copyright © 2010 Royal Meteorological Society and Crown Copyright.
An investigation of Detect, Practice, and Repair to remedy math‐fact deficits in a group of third‐grade students
Authors: Poncy Brian C. , Skinner Christopher H. , Axtell Philip K.
Published: February 2010

A multiple‐probe‐across‐problem‐sets (tasks) design was used to evaluate the effects of the Detect, Practice, and Repair (DPR) on multiplication‐fact fluency development in seven third‐grade students nominated by their teacher as needing remediation. DPR is a multicomponent intervention and begins with a group‐administered, metronome‐paced assessment used to identify specific facts in need of repair. Next, Cover, Copy, and Compare (CCC) procedures are used to enhance automaticity with those specific facts. Lastly, students complete a 1‐min speed drill and self‐graph their fluency performance. Results showed large level and trend increases in fact fluency after DPR was applied across all three sets of multiplication problems. Discussion focuses on the importance of developing effective and efficient basic‐skill‐remediation procedures and directions for future research. © 2010 Wiley Periodicals, Inc.
Intermediate frequency Raman spectra of defective single‐walled carbon nanotubes
Authors: Popov Valentin N. , Lambin Philippe
Published: February 2010

We simulated Raman spectra of defective single‐walled carbon nanotubes within a non‐orthogonal tight‐binding model. The creation of defects in the nanotubes effectively lowers their symmetry and makes a large number of phonons Raman‐active. The Raman spectra of such nanotubes will be similar in shape to their phonon density of states (PDOS). Assuming that for a low density of defects the change of the PDOS is negligible with respect to that of perfect nanotubes, we used the latter as an approximation of the former. The Raman scattering from perfect nanotubes is essentially resonant. Similarly to above, neglecting the change of the electronic structure due to a low density of defects, we adopted the same resonance conditions for defective nanotubes as for perfect ones. Based on these assumptions, we modeled the resonant Raman spectra of a sample of defective nanotubes by means of the PDOS of perfect nanotubes. The obtained results can be used for interpretation of experimental Raman spectra of defective nanotube samples.
Observations of dual slantwise circulations above a cool undercurrent in a mesoscale convective system
Authors: Browning K. A. , Marsham J. H. , Nicol J. C. , Perry F. M. , White B. A. , Blyth A. M. , Mobbs S. D.
Published: February 2010

A series of mesoscale convective systems (MCSs) was observed in the UK during one of the Intensive Observation Periods (IOP 3) in the Convective Storm Initiation Project (CSIP). A detailed case‐study of one of the MCSs, involving some novel interpretation of single Doppler radar data, reveals the evolution of stacked slantwise circulations associated with elevated upright convection. A feature of this occasion was the existence near the surface of a strong undercurrent of cool air flowing against the direction of travel of the storm. The air feeding both the upright and slantwise ascent originated not from near the surface but, rather, from layers between 1 and 3 km. The upright convection was intense at first and was accompanied by a region of dry subsidence surrounding it, together with the alternating layers of slantwise ascent and descent within the storm's precipitation area. When the elevated upright convection weakened, vigorous slantwise motions continued for some time, but their slope decreased from the initial 1 in 4 to 1 in 9. The lowermost layer of slantwise descent corresponded to a moderately intense rear‐inflow jet. The rear‐inflow jet did not penetrate the cool undercurrent and reach the surface; instead, beneath where it impacted the warm air capping the undercurrent, the undercurrent took on the structure of a gravity wave without stagnation. The raised head of the undercurrent lifted overlying air of high wet‐bulb potential temperature sufficiently to overcome the convective inhibition. Copyright © 2010 Royal Meteorological Society
De novo sequencing of two new cyclic θ‐defensins from baboon (Papio hamadryas) leukocytes by matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Stegemann Christin , Tsvetkova Elena V. , Aleshina Galina M. , Lehrer Robert I. , Kokryakov Vladimir N. , Hoffmann Ralf
Published: February 2010

Two cyclic θ‐defensin peptides were isolated from leukocytes of the hamadryas baboon, Papio hamadryas, and purified to homogeneity by gel electrophoresis and reversed‐phase high‐performance liquid chromatography. Both peptides had high in vitro activity against Escherichia coli, Listeria monocytogenes, methicillin‐resistant Staphylococcus aureus (MRSA) and Candida albicans. Here, we report their de novo sequencing by matrix‐assisted laser desorption/ionization tandem time‐of‐flight mass spectrometry (MALDI‐TOF/TOF‐MS). This was accomplished by combining conventional enzymatic digestion with N‐terminal derivatization by 2‐sulfobenzoic acid cyclic anhydride (SACA) or 4‐sulfophenylisothiocyanate (SPITC) to facilitate the interpretation of fragment ion spectra. In addition to the two cyclic θ‐defensins (PhTDs) we also sequenced a novel Papio hamadryas α‐defensin, PhD‐4, which showed high sequence homology to rhesus α‐defensin RMAD‐1 and human α‐defensin HNP‐1. Copyright © 2010 John Wiley & Sons, Ltd.
Characterisation of oxazepam degradation products by high‐performance liquid chromatography/electrospray ionisation mass spectrometry and electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry
Authors: Smyth Thomas J. P. , Robledo Virginia Rodríguez , Smyth W. Franklin
Published: February 2010

Oxazepam has been subjected to controlled degradation at 100°C for 3 h in 0.5 M HCl and 0.5 M NaOH. Following neutralisation of the degradation mixture and removal of salts by solid‐phase extraction (SPE), isocratic high‐performance liquid chromatography/mass spectrometry (HPLC/MS) using water/methanol (25:75 v/v) as the mobile phase was carried out using a flow diverter to collect fractions prior to their characterisation by electrospray ionisation multi‐stage mass spectrometry (ESI‐MSn) and proposal of the corresponding fragmentation patterns. The elemental compositions of the degradation products and their MS fragments were evaluated using electrospray ionisation quadrupole time‐of‐flight tandem mass spectrometry (ESI‐QTOF‐MS/MS) which was then used to support the proposed fragmentation patterns. Copyright © 2010 John Wiley & Sons, Ltd.
Formation of H3O+ from alcohols and ethers induced by intense laser fields
Authors: Shirota Tatsuro , Mano Narutoshi , Tsuge Masashi , Hoshina Kennosuke
Published: February 2010

The processes of H3O+ production from alcohols (ethanol, 2‐propanol, 1‐propanol, 2‐butanol) and ethers (diethyl ether and ethyl methyl ether), and their deuterium‐substituted species, by intense laser fields (800 nm, 100 fs, ∼1 × 1014 W/cm) were investigated through time‐of‐flight (TOF) mass spectrometry. H3O+ formation was observed for all these compounds except for ethyl methyl ether. From the analysis of TOF signals of H(3−n)DnO+ (n = 0, 1, 2, and 3) that have expanding tails with increasing flight time, it has been confirmed that the reaction proceeds through metastable dissociation from the intermediate species C2H(5−m)DmO+(m = 0–5). The common shape of the H(3−n)DnO+ signal profiles contains two major distributions in the time constant, i.e., fast and slow components of <50 ns and ∼500 ns, respectively. The H(3−n)DnO+ branching ratio is interpreted to be the result of complete scrambling of four hydrogen atoms at the CC site in C2H4‐OH+, and partial exchange (18–38%) of a hydrogen atom in the OH group with four other hydrogen atoms within 1 ns prior to H(3−n)DnO+ production. Ab initio calculations for the isomers and transition states of C2H5O+ were also performed, and the observed H(3−n)DnO+ production mechanism has been discussed. In addition, a stable isomer having a complex structure and two isomerization pathways were discovered to contribute to the H3O+ formation process. Copyright © 2010 John Wiley & Sons, Ltd.
Polysaccharide‐Blend Multilayers Containing Hyaluronan and Heparin as a Delivery System for rhBMP‐2
Authors: Crouzier Thomas , Szarpak Anna , Boudou Thomas , Auzély‐Velty Rachel , Picart Catherine
Published: February 2010

It is shown that blend multilayers of hyaluronan (HA) and heparin (HEP) as polyanions and poly(L‐lysine) (PLL) as a polycation can be used to prepare films with different thicknesses and chemical compositions. The amounts of recombinant human BMP‐2 (rhBMP‐2) loaded and the fraction initially released from the films depend on the film's chemical composition. The amounts of rhBMP‐2 loaded in the films are much higher for HA mass fractions of more than 0.4. The bioactivity of the rhBMP‐2‐loaded films is investigated on C2C12 myoblasts, which differentiates into osteoblasts in contact with the films. The alkaline phosphatase expression for cells grown on nanoblend films of various compositions falls over a unique curve. This suggests that the cells “sensing” the rhBMP‐2 are not influenced by the film's chemistry. The rhBMP‐2 can sustain at least three successive culture sequences while remaining bioactive, thus confirming the important and protective effect of rhBMP‐2. Altogether, these results indicate that crosslinked PLL/HA films have superior properties for the incorporation of rhBMP‐2 and on its long‐lasting bioactivity.
Hemangioblastic Derivatives from Human Induced Pluripotent Stem Cells Exhibit Limited Expansion and Early Senescence
Authors: Feng Qiang , Lu Shi-Jiang , Klimanskaya Irina , Gomes Ignatius , Kim Dohoon , Chung Young , Honig George R. , Kim Kwang-Soo , Lanza Robert
Published: February 2010

Human induced pluripotent stem cells (hiPSC) have been shown to differentiate into a variety of replacement cell types. Detailed evaluation and comparison with their human embryonic stem cell (hESC) counterparts is critical for assessment of their therapeutic potential. Using established methods, we demonstrate here that hiPSCs are capable of generating hemangioblasts/blast cells (BCs), endothelial cells, and hematopoietic cells with phenotypic and morphologic characteristics similar to those derived from hESCs, but with a dramatic decreased efficiency. Furthermore, in distinct contrast with the hESC derivatives, functional differences were observed in BCs derived from hiPSCs, including significantly increased apoptosis, severely limited growth and expansion capability, and a substantially decreased hematopoietic colony-forming capability. After further differentiation into erythroid cells, >1,000-fold difference in expansion capability was observed in hiPSC-BCs versus hESC-BCs. Although endothelial cells derived from hiPSCs were capable of taking up acetylated low-density lipoprotein and forming capillary-vascular-like structures on Matrigel, these cells also demonstrated early cellular senescence (most of the endothelial cells senesced after one passage). Similarly, retinal pigmented epithelium cells derived from hiPSCs began senescing in the first passage. Before clinical application, it will be necessary to determine the cause and extent of such abnormalities and whether they also occur in hiPSCs generated using different reprogramming methods.
Integrating 3D images using laboratory‐based micro X‐ray computed tomography and confocal X‐ray fluorescence techniques
Authors: Patterson Brian M. , Campbell John , Havrilla George J.
Published: February 2010

The application of non‐destructive imaging to characterizing samples has become more important as the costs of samples increase. Imaging a sample via X‐ray techniques is preferable when altering or even touching the sample affects its properties, or when the sample is fielded after characterization. Two laboratory‐based X‐ray techniques used at Los Alamos include micro X‐ray computed tomography (MXCT) and confocal micro X‐ray fluorescence (confocal MXRF). Both methods create a 3D rendering of the sample non‐destructively. MXCT produces a high‐resolution (sub‐µm voxel) rendering of the sample based upon X‐ray absorption; the resulting model is a function of density and does not contain any elemental information. Confocal MXRF produces an elementally specific 3D rendering of the sample, but at a lower (30 × 30 × 65 µm) resolution. By combining data from these two techniques, scientists provided a more comprehensive method of analysis. We will describe a MATLAB routine written to render each of these data sets individually and/or within the same coordinate system. This approach is shown in the analysis of two samples: an integrated circuit surface mounted resistor and a machined piece of polystyrene foam. The samples chosen provide an opportunity to compare and contrast the two X‐ray techniques, identify their weaknesses and show how they are used in a complementary fashion. Copyright © 2010 John Wiley & Sons, Ltd.
Design and characterization of a constitutively open KcsA
Authors: Cuello Luis G. , Jogini Vishwanath , Cortes D. Marien , Sompornpisut Amornrat , Purdy Michael D. , Wiener Michael C. , Perozo Eduardo
Published: February 2010

The molecular nature of the structure responsible for proton sensitivity in KcsA has been identified as a charge cluster that surrounds the inner helical bundle gate. Here, we show that this proton sensor can be modified to engineer a constitutively open form of KcsA, amenable to functional, spectroscopic and structural analyses. By combining charge neutralizations for all acidic and basic residues in the cluster at positions 25, 117–122 and 124 (but not E118), a mutant KcsA is generated that displays constitutively open channel activity up to pH 9. The structure of this mutant revealed that full opening appears to be inhibited by lattice forces since the activation gate seems to be only on the early stages of opening.
RNA interference‐mediated suppression of xanthine dehydrogenase reveals the role of purine metabolism in drought tolerance in Arabidopsis
Authors: Watanabe Shunsuke , Nakagawa Ayami , Izumi Shunsuke , Shimada Hiroshi , Sakamoto Atsushi
Published: February 2010

We have previously demonstrated that RNA interference‐mediated suppression of xanthine dehydrogenase (XDH), the rate‐limiting enzyme in purine degradation, causes defects in the normal growth and development of Arabidopsis thaliana. Here, we investigated a possible role for XDH in drought tolerance, since this enzyme is also implicated in plant stress responses and acclimatization. When XDH‐suppressed lines were subjected to drought stress, plant growth was markedly reduced in conjunction with significantly enhanced cell death and H2O2 accumulation. This drought‐hypersensitive phenotype was reversed by pretreatment with exogenous uric acid, the catalytic product of XDH. These results suggest that fully functional purine metabolism plays a role in the Arabidopsis drought acclimatization.