bluuebunny/crossref_metadata_2025_split huggingface dataset:
Field notes on administering shock modules
Authors: De Weerdt Joachim 
Published: April 2008

AbstractIncreasingly panel household questionnaires in developing countries will include a shock module to collect information on past shocks experienced by the household. Still, very little information is available on what one needs to take into consideration when designing these modules. This note discusses field experiences gained from piloting a shock module in the Kagera Region of Tanzania. Pilots were conducted with two fundamentally different designs of shock modules. We discuss the advantages and disadvantages of using a structural form shock module, which walks the respondent through a list of shocks, and compare it to using a reduced form one, which probes for welfare changes over time. Copyright © 2008 John Wiley & Sons, Ltd.
A cytoprotective role for the heme oxygenase‐1/CO pathway during neural differentiation of human mesenchymal stem cells
Authors: Barbagallo Ignazio , Tibullo Daniele , Di Rosa Michelino , Giallongo Cesarina , Palumbo Giuseppe A. , Raciti Giuseppina , Campisi Agata , Vanella Angelo , Green Colin J. , Motterlini Roberto 
Published: April 2008

AbstractThe inducible protein heme oxygenase‐1 (HO‐1) catalyzes the oxidation of heme to carbon monoxide (CO) and biliverdin, which play a concerted action in cytoprotection against oxidative stress and in the modulation of cell proliferation and differentiation. Here we report that both HO‐1 expression and activity can be highly increased in undifferentiated human mesenchymal stem cells (MSCs) treated with hemin, a known HO‐1 inducer. However, HO‐1 mRNA and protein expression gradually decrease when MSCs undergo neural differentiation in vitro, making them extremely susceptible to glutamate‐mediated cytotoxicity. A time course for HO‐1 revealed that this protein is markedly down‐regulated after 2 days and returns to control levels 6 days after differentiation. Treatment with glutamate (250 μM) after 2 days of neural differentiation resulted in a more pronounced lactate dehydrogenase release, a marker of cell injury, compared with undifferentiated cells. Notably, cells pretreated with hemin (50 μM) or compounds that release small amounts of CO (10 μM CORM‐3 and CORM‐A1) rendered cells more resistant to glutamate‐induced toxicity; this effect was evident in both undifferentiated and differentiated MSCs. Our findings indicate that MSCs become more vulnerable to oxidative injury during the early stages of differentiation via mechanisms that involve a temporary inhibition of HO‐1 expression. Thus, overexpression of HO‐1 and CO‐releasing molecules could provide a possible therapeutic strategy to improve cell viability during neural differentiation in applications that use stem cell technology. © 2008 Wiley‐Liss, Inc.
Distribution of mitochondria along small‐diameter myelinated central nervous system axons
Authors: Edgar Julia M. , McCulloch Mailis C. , Thomson Christine E. , Griffiths Ian R. 
Published: April 2008

AbstractSmall‐diameter myelinated CNS axons are preferentially affected in multiple sclerosis (MS) and in the hereditary spastic paraplegias (HSP), in which the distal axon degenerates. Mitochondrial dysfunction has been implicated in the pathogenesis of these and other disorders involving axonal degeneration. The aim of this study was to determine whether the frequency of axonal mitochondria changes along the length of small‐diameter fibers and whether there is a preferential localization to the region of the node of Ranvier. We find that mitochondrial numbers do not change along the length of a myelinated small‐diameter fiber, and, in contrast to the peripheral nervous system, there is no tendency for mitochondrial numbers to increase at the node. © 2008 Wiley‐Liss, Inc.
Selective death of newborn neurons in hippocampal dentate gyrus following moderate experimental traumatic brain injury
Authors: Gao Xiang , Deng‐Bryant Ying , Cho Wongil , Carrico Kimberly M. , Hall Edward D. , Chen Jinhui 
Published: April 2008

AbstractMemory impairment is one of the most significant residual deficits following traumatic brain injury (TBI) and is among the most frequent complaints heard from patients and their relatives. It has been reported that the hippocampus is particularly vulnerable to TBI, which results in hippocampus‐dependent cognitive impairment. There are different regions in the hippocampus, and each region is composed of different cell types, which might respond differently to TBI. However, regional and cell type‐specific neuronal death following TBI is not well described. Here, we examined the distribution of degenerating neurons in the hippocampus of the mouse brain following controlled cortical impact (CCI) and found that the majority of degenerating neurons observed were in the dentate gyrus after moderate (0.5 mm cortical deformation) CCI‐TBI. In contrast, there were only a few degenerating neurons observed in the hilus, and we did not observe any degenerating neurons in the CA3 or CA1 regions. Among those degenerating cells in the dentate gyrus, about 80% of them were found in the inner granular neuron layer. Analysis with cell type‐specific markers showed that most of the degenerating neurons in the inner granular neuron layer are newborn immature neurons. Further quantitative analysis shows that the number of newborn immature neurons in the dentate gyrus is dramatically decreased in the ipsilateral hemisphere compared with the contralateral side. Collectively, our data demonstrate the selective death of newborn immature neurons in the hippocampal dentate gyrus following moderate injury with CCI in mice. This selective vulnerability of newborn immature dentate neurons may contribute to the persistent impairment of learning and memory post‐TBI and provide an innovative target for neuroprotective treatment strategies. © 2008 Wiley‐Liss, Inc.
Identification of the Fugloyarbanki tephra in the NGRIP ice core: a key tie‐point for marine and ice‐core sequences during the last glacial period
Authors: Davies S. M. , Wastegård S. , Rasmussen T. L. , Svensson A. , Johnsen S. J. , Steffensen J. P. , Andersen K. K. 
Published: April 2008

AbstractA visible tephra horizon in the NGRIP ice core has been identified by geochemical analysis as the Fugloyarbanki Tephra, a widespread marker horizon in marine cores from the Faroe Islands area and the northern North Atlantic. An age of 26 740 ± 390 yr b2k (1σ uncertainty) is derived for this tephra according to the new Greenland Ice Core Chronology (GICC05) based on multi‐parameter counting of annual layers. Detection of this tephra for the first time within the NGRIP ice core provides a key tie‐point between marine and ice‐core records during the transition between MIS 3 and 2. Identification of this volcanic event within the Greenland records demonstrates the future potential of using tephrochronology to precisely correlate palaeoarchives in widely separated localities that span the last glacial period, as well as providing a potential method for examining the extent of the radiocarbon marine reservoir effect at this time. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of column temperature on enantioseparation of dihydropyrimidinones using alcohol solvated Chiralpak AS and AS‐H columns
Authors: Wang Fang , Han Jun , Yeung David , Semin David , Cheetham Janet 
Published: April 2008

AbstractIn this study we report the application of column temperature programs to compare the chromatographic behaviors of four commercially available dihydropyrimidinone (DHP) compounds on Chiralpak AS and AS‐H phases under different alcohol solvation conditions such as 1‐propanol (1‐PrOH), 2‐methyl‐1‐PrOH (2‐Me‐1‐PrOH), 1‐butanol (1‐BuOH), 2‐BuOH, and tert‐BuOH (t‐BuOH) in n‐hexane (n‐Hex). It was observed that the apparent retention factors of the DHP compounds on the AS phase in t‐BuOH/n‐Hex mobile phase had the largest reduction (>27%) among the mobile phases studied after a heating and cooling temperature cycle (10 to 50 back to 10°C). However, the average reduction of the apparent retention factors of the compounds on t‐BuOH solvated AS‐H was less than 4%. No clear trend of changes in the apparent retention factors on AS and AS‐H columns was observed in other alcohol modified mobile phases. Step‐temperature programs showed that alcohol solvated AS phase had larger changes in the apparent retention factors with time than those of AS‐H phase at the elevated temperature step (50°C). Both t‐BuOH solvated AS and AS‐H phases showed kinetic behaviors in chromatographic processes at the elevated temperature.
Preparation and HPLC evaluation of a new 1,3‐alternate 25,27‐bis‐[p‐chlorobenzyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene silica bonded stationary phase
Authors: Sliwka‐Kaszynska Magdalena , Karaszewski Sebastian 
Published: April 2008

AbstractThe 1,3‐alternate 25,27‐bis‐[p‐chlorobenzyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene‐bonded silica gel stationary phase was synthesized, structurally characterized, and used as a selector in high performance liquid chromatography. Selectivity studies on that phase used aromatic positional isomers, alkylbenzenes, polynuclear aromatic hydrocarbons, sulfonamides, and non‐steroidal anti‐inflammatory drugs as analytes. The effects of organic modifier content and pH of the mobile phase on retention and selectivity of selected aromatic positional isomers were studied. Selectivity comparisons of the novel phase vs. 1,3‐alternate 25,27‐di‐[benzyloxy]‐26,28‐bis‐[3‐propyloxy]‐calix[4]arene phase and commercially available RP‐Phenyl phases were performed. The retention mechanism was also discussed. The results indicated that the calixarene stationary phase behaves like a reversed‐phase packing; however, other retention mechanisms seem to be involved in the separation process.
Proteome analysis of non‐model plants: A challenging but powerful approach
Authors: Carpentier Sebastien Christian , Panis Bart , Vertommen Annelies , Swennen Rony , Sergeant Kjell , Renaut Jenny , Laukens Kris , Witters Erwin , Samyn Bart , Devreese Bart 
Published: April 2008

AbstractBiological research has focused in the past on model organisms and most of the functional genomics studies in the field of plant sciences are still performed on model species or species that are characterized to a great extent. However, numerous non‐model plants are essential as food, feed, or energy resource. Some features and processes are unique to these plant species or families and cannot be approached via a model plant. The power of all proteomic and transcriptomic methods, that is, high‐throughput identification of candidate gene products, tends to be lost in non‐model species due to the lack of genomic information or due to the sequence divergence to a related model organism. Nevertheless, a proteomics approach has a great potential to study non‐model species. This work reviews non‐model plants from a proteomic angle and provides an outline of the problems encountered when initiating the proteome analysis of a non‐model organism. The review tackles problems associated with (i) sample preparation, (ii) the analysis and interpretation of a complex data set, (iii) the protein identification via MS, and (iv) data management and integration. We will illustrate the power of 2DE for non‐model plants in combination with multivariate data analysis and MS/MS identification and will evaluate possible alternatives. © 2008 Wiley Periodicals, Inc., Mass Spec Rev 27: 354–377, 2008
NMR and Texture Analyses in Relation to Swelling Kinetics of 2‐Hydroxyethyl Methacrylate/N‐Vinylpyrrolidinone Hydrogels
Authors: Ng Loo‐Teck , Swami Salesh 
Published: April 2008

AbstractThis study investigates the relationship between swelling kinetics and the relative stress relaxation (SR) values from texture analysis, as well as the relaxation times from proton NMR analysis of photopolymerized 2‐hydroxyethyl methacrylate (HEMA)/N‐vinyl pyrrolidinone (NVP) hydrogels with varying HEMA and NVP contents. Swelling tests in Milli‐Q water at 37 °C showed that hydrogels of higher NVP content displayed non‐Fickian diffusion kinetics. Texture analysis indicated the existence of a trend between SR values and diffusion kinetics with the hydrogels that displayed non‐Fickian diffusion having significantly lower SR values. Proton NMR analysis showed that the hydrogel with higher NVP content (non‐Fickian diffusion kinetics) displayed substantially longer relaxation times, which indicated slower exchange of water molecules between different sites within the meshes of the polymer matrix, attributable probably to hydrogen bonding and hydrophilic attraction between polymer and the water molecules. A relationship appeared to exist for the hydrogels understudy with hydrogels exhibiting non‐Fickian diffusion kinetics displaying lower SR values and longer relaxation times.
Effect of Non‐Woven Carbon Nanofiber Mat Presence on Cure Kinetics of Epoxy Nanocomposites
Authors: Aussawasathien Darunee , Sancaktar Erol 
Published: April 2008

AbstractSummary: An investigation was carried out into the cure kinetics of carbon nanofiber (CNF) mat‐epoxy nanocomposites, composed of bisphenol‐A based epoxy resin and diethylene triamine as a curing agent. It was observed that the rate of cure reaction for CNF mat‐epoxy nanocomposites was higher than that for neat epoxy resin at low curing temperatures and the presence of the CNF mat produced the maximum influence at a certain curing temperature and time. At high curing temperature and long curing times, the effect of CNF mat on the cure rate was insignificant. The CNF mat‐epoxy composite exhibited somewhat lower value of activation energy than that of the neat epoxy system at the beginning of the curing stage. The weight fraction of CNF mat also affected the cure reaction of epoxy nanocomposites at the same curing temperature. As the amount of CNF mat increased, the cure rate was higher at the same cure time. However, at high CNF mat loading, the cure reaction was retarded since the amount of epoxy and hardener decreased dramatically at high CNF contents together with the hindering effect of the CNF mat on the diffusion of epoxy resin and the curing agent, leading to lower crosslinking efficiency. Although the curing efficiency of epoxy nanocomposites dropped at high CNF mat content, the glass transition temperature (Tg) was still high due to the ultra‐high strength of the CNF mat. The cure kinetics of CNF mat‐epoxy nanocomposites was in good agreement with Kamal's model.
Effect of Zinc Oxide on Morphology and Mechanical Properties of Polyoxymethylene/Zinc Oxide Composites
Authors: Wacharawichanant Sirirat 
Published: April 2008

AbstractThis paper studies the effects of zinc oxide (ZnO) on morphology and mechanical properties of pure polyoxymethylene (POM) and POM/ZnO composites. POM/ZnO composites with varying concentration of ZnO were prepared by melt mixing technique in a twin screw extruder. The dispersion of ZnO particles on POM composites was studied by scanning electron microscope (SEM). It is observed that the dispersion of ZnO particles is relatively good. The mechanical properties of the composites such as tensile strength, stress at break, Young's modulus and impact strength were measured. Increasing content of ZnO up to 4.0 wt% increases the impact strength of POM. Addition of ZnO beyond 4.0 wt% decreases the impact strength. The composites containing ZnO content greater than 2.0 wt% show increased Young's Modulus. The tensile strength and stress at break decrease with increasing ZnO content. This may be due to the compatibility between ZnO and POM.
Effect of Heat Treatment Temperature on Surface Topography and Hydrophobicity of Polydimethylsiloxane/Titanium Oxide Hybrid Films
Authors: Jindasuwan Sunisa , Sujaridworakun Pornapa , Jinawath Supatra , Supothina Sitthisuntorn 
Published: April 2008

AbstractHydrophobic thin films of polydimethylsiloxane (PDMS) ‐ titamium (hydrous) oxide hybrid material were deposited on glass substrate by dip coating from the precursor containing hydroxyl‐terminated PDMS and titanium tetraisopropoxide (TIP), as well as small amounts of water and ethyl acetoacetate. Film's hydrophobicity was evaluated by performing contact angle measurement, while surface topography was analyzed by using an atomic force microscope (AFM). Effects of heat treatment temperature and TIP:PDMS ratio on film's hydrophobicity are described.
Molecular Functionalization of Cold‐Plasma‐Treated Bombyx mori Silk
Authors: Nimmanpipug Piyarat , Lee Vannajan Sanghiran , Janhom Sorapong , Suanput Pradoong , Boonyawan Dherawan , Tashiro Kohji 
Published: April 2008

AbstractBombyx mori silk treated by cold SF6 plasma was found to show higher hydrophobic property than the original silk. In order to clarify the chemical changes occurring in this treatment, the changes of functional groups of silk surface were investigated by attenuated total reflection (ATR) infrared spectroscopy, surface charge determination, and quantum mechanical calculation. Infrared spectra of original and plasma‐treated silks do not show any change in the frequency regions of amide I, II, and III bands which locate at around 1627, 1513, and 1228 cm−1, respectively. Slight changes were detected for the peak intensities of the bands locating in the frequency region of 1000–1050 cm−1 after plasma treatment. This suggests the formation of CF groups in the Bombyx mori silk chain. The zeta potential experiment suggested that the electrostatic charges of the silk surface were not affected by the plasma treatment. In order to investigate the surface state of the plasma treated silk, the density functional calculation was performed for the model compounds with similar chemical structure as that of Bombyx mori silk. In this calculation, a fluorine radical was located at the various positions of the model compound, and the energetically most plausible structures were extracted to show the chemical reaction of CH + F− → CF + H−.
Synthesis and Characterization of Poly(ether‐block‐amide) Membranes
Authors: Mohammadi Toraj , Kikhavandi Towan , Moghbeli Mohammadreza 
Published: April 2008

AbstractPoly(ether‐block‐amide) membranes were made via casting a solution on a nonsolvent (water) surface. In this research, effects of different parameters such as ratio of solvent mixture (n‐butanol/isopropanol), temperature, composition of coagulation bath (water) and polymer concentration, on quality of the thin film membranes were studied. The mechanism of membrane formation involves solution spreading, solvent–nonsolvent exchange, and partial evaporation of the solvent steps. Solvent‐ nonsolvent exchange is the main step in membrane formation and determines membrane morphology. However, at higher temperature of polymeric solution greater portion of solvent evaporates. The results showed that type of demixing process (mutual affinity between solvent and nonsolvent) has important role in film formation. Also, addition of solvent to the nonsolvent bath is effective on membrane morphology. The film quality enhances with increasing isopropanol ratio in the solvent mixture. This behavior can be related to increasing of solution surface tension, reduction of interfacial tension between solution and nonsolvent and delayed solvent‐nonsolvent demixing. Uniform films were made at a temperature rang of 60–80 °C and a polymer concentration of 4–7 wt%. Morphology of the membranes was investigated with scanning electron micrograph (SEM). Pervaporation of ethyl butyrate/water mixtures was studied using these membranes and high separation performance was achieved. For ethyl butyrate/water mixtures, It was observed that both permeation flux and separation factor increase with increasing ethyl butyrate content in the feed. Increasing temperature in limited range studied resulted in decreasing separation factor and increasing permeation flux.
The Curing Efficiency and Mechanical Properties of Light‐Activated Acrylic Resin
Authors: Channasanon Somruethai , Tanodekaew Siriporn 
Published: April 2008

AbstractThe aim of this investigation was to determine degree of conversion, and flexural and compressive strength of photocurable acrylic resin. The acrylic resins based on bis‐phenol A glycidyl dimethacrylate (BisGMA) and triethylene glycol dimethacrylate (TEGDMA) were formulated and then irradiated with red light to form a solid crosslinked polymer. Various post curing conditions were studied to investigate their effects on curing efficiency. Degree of conversion was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR) to monitor the quantity of remaining acrylic double bond in the cured resin. Three‐point bending and compressive strength were tested using Universal Testing Machine (UTM) to evaluate the mechanical performance. Our investigation demonstrated that the formulated acrylic resins were possibly polymerized under irradiation with red light and degree of conversion and mechanical properties were closely correlated.
Synthesis, Characterization and Biospecific Degradation Behavior of Sulfated Chitin
Authors: Jayakumar Rangasamy , Nwe Nitar , Nagagama Hideaki , Furuike Tetsuya , Tamura Hiroshi 
Published: April 2008

AbstractChitin is a polysaccharide found in the outer skeleton of insects, crabs, shrimps, and lobsters and in the internal structures of other invertebrates. Sulfated chitin was prepared by reacting carboxymethyl chitin (CM‐chitin) with 2‐aminoethane sulfonic acid by using 1‐ethyl‐3‐(3‐dimethylaminopropyl)carbodiimide (EDC) catalyst. The prepared sulfated chitin was characterized by FTIR, elemental analysis, thermogravimetric analysis (TGA) and X‐ray diffraction (XRD). The degree of substitution was found to be 0.98 by elemental analysis. The TGA studies showed that sulfated chitin was less thermal stability than carboxymethyl chitin. This is due to the grafting reaction. The sulfated chitin membranes were prepared from sulfated chitin and then crosslink with glutaradehyde. The biodegradation process was performed in PBS (pH 7.4) containing lysozyme (10 µg/ml) at 37 °C in an incubator. Experimental results from weight loss throughout the study showed that the biospecific degradation occur on the membrane by lysozyme.
Polymeric Membrane Nanofiltration and Its Application to Separations in the Chemical Industries
Authors: Sereewatthanawut Issara , Boam Andrew T. , Livingston Andrew G. 
Published: April 2008

AbstractThe application of membrane technology, particularly water‐based nanofiltration, as a separation process in the chemical industries has increased tremendously in recent years. However, the use of membranes capable of molecular separation in non‐aqueous systems (e.g. nanofiltration) is a relatively new and growing application of membrane technology. The main challenge in applying polymeric nanofiltration membranes to non‐aqueous systems is that the polymers developed for water‐based applications are not suitable. Polyimide is a particularly interesting polymer as it has excellent chemical resistance, and membranes produced from it provide desirable separation properties – i.e. economically viable flux and good separation of nanoscale molecules. Various research works have shown that commercial polyimide organic solvent nanofiltration (OSN) membranes, trademark STARMEM™,1are robust and suitable for performing molecular separations. This work will discuss in detail the use of STARMEM™ in a pharmaceutical application. The EIC‐OSN process was developed for separating the enantiomers of chiral compounds in pharmaceutical applications. High optical purity (94.9%) of (S)‐phenylethanol fromrac‐phenylethanol was achieved through the use of STARMEM™122. Process simulation of the ideal eutomer‐distomer system predicted that the highest theoretical resolvability from this process would be 99.2%. Other application areas of OSN are varied, including purification and fractionation in the natural products industry, homogeneous catalyst recovery, monomer separation from oligomers, etc. Currently, OSN is used in a small number of processes including a very large petrochemical application, but it has the potential to be applied to a wide range of separations across the full spectrum of the chemical industries.