bluuebunny/crossref_metadata_2025 huggingface dataset:
Process intensification using a two‐phase system and micromixing for consecutive and reversible reactions
Authors: Okubo Yoshihito , Mae Kazuhiro
Published: April 2009

This study aimed to find reaction conditions that improve the yield of target intermediate products, using a two‐phase system and a microspace for first‐order consecutive and reversible reactions. As a result, the yield of target products with a two‐phase system can be surpassed by that of a single‐phase system through selecting the organic phase such that the partition coefficient of the raw material to the aqueous phase is large, and that of the target product to the organic phase is also large. In addition, the volume ratio of two phases and the liquid–liquid interfacial area are also important factors for improving the target product yield. In a microspace, the microfluid segments can be designed both arbitrarily and precisely, and thus it is possible to control the interfacial area and mass transfer rates accurately. Utilization of a microspace can play a significant role in intensifying a two‐phase system. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Flow characteristics of thermo‐responsive microspheres in microchannel during the phase transition
Authors: Zhou Ming‐Yu , Xie Rui , Ju Xiao‐Jie , Zhao Ze‐Lin , Chu Liang‐Yin
Published: April 2009

To probe into the flow and aggregation behaviors of thermo‐responsive microspheres in microchannel during the phase transition, the flow characteristics of monodisperse poly(n‐isopropylacrylamide) (PNIPAM) microspheres in microchannel with local heating are investigated systematically. When the fluid temperature in the microchannel increases across the lower critical solution temperature (LCST), the PNIPAM microspheres finish the phase transition within 10 s and are easily get aggregated during the phase transition. The diameter ratio of microsphere to microchannel, number of microspheres, initial distance between microspheres, and flow direction of fluid in microchannel, are key parameters affecting the flow and aggregation behaviors of the microspheres in microchannel during the phase transition. If a proper combination of these parameters is designed, the microspheres can aggregate together during the phase transition and stop automatically at a desired position in the microchannel by local heating, which is what the targeting drug delivery system expected. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Incidence of the mucopolysaccharidoses in Taiwan, 1984–2004
Authors: Lin Hsiang‐Yu , Lin Shuan‐Pei , Chuang Chih‐Kuang , Niu Dau‐Ming , Chen Ming‐Ren , Tsai Fuu‐Jen , Chao Mei‐Chyn , Chiu Pao‐Ching , Lin Shio‐Jean , Tsai Li‐Ping , Hwu Wuh‐Liang , Lin Ju‐Li
Published: April 2009

Previous studies on the incidence of the various types of mucopolysaccharidoses (MPS) in different populations have shown considerable variation. However, information regarding the incidence of MPS in the Asian population is lacking. An epidemiological study of the MPS disorders in Taiwan using multiple ascertainment sources was undertaken, and incidences of different types of MPS during the period of 1984–2004 were estimated. We compared our data with previous reports in different populations. The combined birth incidence for all MPS cases was 2.04 per 100,000 live births. MPS II (Hunter syndrome) had the highest calculated birth incidence of 1.07 per 100,000 live births (2.05 per 100,000 male live births), comprising 52% of all MPS cases diagnosed. The birth incidences of MPS I (Hurler syndrome), III (Sanfilippo syndrome), IV (Morquio syndrome), and VI (Maroteaux‐Lamy syndrome) were 0.11, 0.39, 0.33, and 0.14 per 100,000 live births, respectively, which accounted for 6%, 19%, 16%, and 7% of all MPS, respectively. No cases of MPS III D (Sanfilippo syndrome type D), MPS IV B (Morquio syndrome type B), MPS VII (Sly syndrome) or MPS IX were ascertained during the study period. Overall incidence of MPS in Taiwan was consistent with that reported in Western populations. However, in contrast to the higher incidence of MPS I in most Western populations, this study showed a higher incidence of MPS II in Taiwan. It remains to be investigated whether this discrepancy is attributed to the under‐diagnosis of MPS I in Taiwan or to ethnic differences. © 2009 Wiley‐Liss, Inc.
Late‐onset Lennox–Gastaut syndrome in a patient with 15q11.2–q13.1 duplication
Authors: Orrico Alfredo , Zollino Marcella , Galli Lucia , Buoni Sabrina , Marangi Giuseppe , Sorrentino Vincenzo
Published: April 2009

The 4 Mb 15q11–q13 region is prone to structural rearrangements. Deletions have been identified among the leading causes for genetic diseases such as the Prader–Willi and Angelman syndromes, while duplications, occurring preferentially on the maternal chromosome, produce a typical phenotype that includes mental retardation, language delay, seizures and autism. Although a number of such patients have been reported, however, there is a paucity of information about their clinical outcomes in adult age. We report on a 33‐year‐old female with a microduplication of 15q11–q13 detected by array‐CGH analysis, with particular reference to the epilepsy phenotype, characterized as a late‐onset Lennox–Gastaut syndrome. © 2009 Wiley‐Liss, Inc.
Craniosynostosis in patients with Noonan syndrome caused by germline KRAS mutations
Authors: Kratz Christian P. , Zampino Giuseppe , Kriek Marjolein , Kant Sarina G. , Leoni Chiara , Pantaleoni Francesca , Oudesluys‐Murphy Anne Marie , Di Rocco Concezio , Kloska Stephan P. , Tartaglia Marco , Zenker Martin
Published: April 2009

Craniosynostosis, the premature fusion of one or more cranial sutures, is a developmental defect that disrupts the cranial morphogenetic program, leading to variable dysmorphic craniofacial features and associated functional abnormalities. Craniosynostosis is frequently observed as an associated feature in a number of clinically and genetically heterogeneous syndromic conditions, including a group of disorders caused by activating mutations in genes coding for the fibroblast growth factor receptor family members FGFR1, FGFR2, and FGFR3. In these disorders, dysregulation of intracellular signaling promoted by the aberrant FGFR function is mediated, at least in part, by the RAS‐MAPK transduction pathway. Mutations in KRAS, HRAS, and other genes coding for proteins participating in this signaling cascade have recently been identified as underlying Noonan syndrome (NS) and related disorders. While cardinal features of these syndromes include distinctive dysmorphic facial features, reduced growth, congenital heart defects, and variable ectodermal anomalies and cognitive impairment, craniosynostosis is not a recognized feature. Here, we report on the occurrence of premature closure of cranial sutures in subjects with NS, and their specific association with mutations in the KRAS gene. These findings highlight the pathogenetic significance of aberrant signaling mediated by the RAS signaling pathway in other known forms of craniosynostosis, and suggest that, even in the absence of radiologically demonstrable synostosis of the calvarian sutures, dysregulated growth and/or suture closure at specific craniofacial sites might contribute to the craniofacial anomalies occurring in NS. © 2009 Wiley‐Liss, Inc.
Homozygous female Becker muscular dystrophy
Authors: Fujii Katsunori , Minami Narihiro , Hayashi Yukiko , Nishino Ichizo , Nonaka Ikuya , Tanabe Yuzo , Takanashi Jun‐ichi , Kohno Yoichi
Published: April 2009

We report, for the first time, on a female Becker muscular dystrophy (BMD) patient with homozygous dystrophin deletion. The 14‐year‐old patient, product of consanguineous parents, presented with a 7‐year history of exercise intolerance and recurrent myoglobinuria. Although CK was elevated to 1,800 U/L, no muscle weakness, atrophy, or hypertrophy was seen on examination. Muscle pathology demonstrated a minimal dystrophic change and faint dystrophin staining pattern. Semi‐quantitative PCR of dystrophin revealed a homozygous dystrophin deletion of exons 45–55, which is predicted to remove 593 amino acids without frame shifting. Western blot analysis of skeletal muscle for dystrophin showed a 306 kDa band; thus, we made a diagnosis of female BMD. We confirmed identical deletion in both father and mother, in hemizygous and heterozygous modes, respectively. Neither female Duchenne muscular dystrophy (DMD) nor BMD due to homozygous dystrophin mutation has ever been identified although female DMD has been found in patients with Turner syndrome or unilateral parental disomy for X chromosome. Our results indicate that dystrophinopathy can also be caused in females by homozygosity, albeit rare. © 2009 Wiley‐Liss, Inc.
Health care supervision for twin pairs
Authors: Samanich Joy
Published: April 2009

Twins are at increased risk for congenital anomalies and have particular health care needs, but twin management guidelines do not exist. This review attempts to integrate the latest research findings and evidence‐based medicine on twins into basic clinical recommendations for general pediatricians. © 2009 Wiley‐Liss, Inc.
Sexual behavior in female western lowland gorillas (Gorilla gorilla gorilla): evidence for sexual competition
Authors: Stoinski Tara S. , Perdue Bonnie M. , Legg Angela M.
Published: April 2009

Previous research in gorillas suggests that females engage in post‐conception mating as a form of sexual competition designed to improve their own reproductive success. This study focused on sexual behaviors in a newly formed group of western lowland gorillas (Gorilla gorilla gorilla) housed at Zoo Atlanta. All females engaged in mating outside their conceptive periods, although there was individual variation in the frequency of the behavior. An analysis of the presence/absence of sexual behavior found females, regardless of reproductive condition, were more likely to engage in sexual behavior on days when other females were sexually active. On these “co‐occurrence” days, females were significantly more likely to solicit the silverback, but copulations did not differ from expectation. The results find further evidence for sexual competition among female gorillas and suggest that this may occur throughout their reproductive cycle rather than only during pregnancy. Am. J. Primatol. 71:587–593, 2009. © 2009 Wiley‐Liss, Inc.
Rational Design of an Organometallic Glutathione Transferase Inhibitor
Authors: Ang Wee Han , Parker Lorien J. , De Luca Anastasia , Juillerat‐Jeanneret Lucienne , Morton Craig J. , Lo Bello Mario , Parker Michael W. , Dyson Paul J.
Published: April 2009

Double trouble: A hybrid organic–inorganic (organometallic) inhibitor was designed to target glutathione transferases. The metal center is used to direct protein binding, while the organic moiety acts as the active‐site inhibitor (see picture). The mechanism of inhibition was studied using a range of biophysical and biochemical methods.

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Evaluation of new 3‐mercaptopropionate thiols for thiol‐ene photopolymerization coatings using experimental design
Authors: Wutticharoenwong Kosin , Soucek Mark D.
Published: April 2009

Three 3‐mercaptopropionate thiols, 1,6‐Hexane bis(3‐mercaptopropionate) (HD‐SH), trans‐1,4‐Cyclohexanedimethyl bis(3‐mercaptopropionate) (CHDM‐SH), and 4,4′‐Isopropylidenedicyclohexane bis(3‐mercaptopropionate) (HBPA‐SH) were formulated with 1,3,5‐triallyl‐1,3,5‐triazine‐2,4,6(1H,3H,5H)‐trione (TATATO) and photoinitiator. The formulations were photopolymerized via thiol‐ene photopolymerization. A ternary experimental design was employed to elucidate the influence the three thiols on the thermomechanical and coatings properties of thiol‐ene photopolymerizable materials. Tensile strength, tensile modulus, elongation‐to‐break, glass transition temperature (Tg), and crosslink density (XLD) were investigated. Coating properties including pencil hardness, pull‐off adhesion, MEK double rubs, and gloss were also investigated. Relative reaction conversion was determined by photo differential scanning calorimeter (PDSC). Thiol‐ene photopolymerizable materials containing HBPA‐SH resulted in improving tensile strength, tensile modulus, Tg, and pencil hardness but lowering of crosslink density and relative conversion. This was attributed to steric and rigidity of the double cycloaliphatic structure. The inclusion of CHDM‐SH into the systems resulted in the synergistic effect on elongation‐to‐break and pull‐off adhesion. The HD‐SH generally resulted in a diminution of thermomechanical and coating properties, but improved the crosslink density. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Encapsulation of diclofenac sodium with acidic copolymer hydrogels based on PEG/poly(N‐isopropylacrylamide‐co‐2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid) semi‐interpenetrating network using in situ loading technique
Authors: Zhang Chi , Easteal Allan J.
Published: April 2009

A pH‐ and temperature‐responsive semi‐interpenetrating copolymer PEG6000/poly(NIPA‐co‐AMPS) (PEG/AMPS‐co‐NIPA SIPN), for short PEG SIPN, was made by ammonium persulfate‐initiated suspension copolymerization of N‐isopropylacrylamide, 2‐acrylamido‐2‐methylpropanesulphonic acid, and N,N′‐methylene‐bis‐acrylamide (MBAA; crosslinker) in the presence of PEG6000. The PEG SIPN copolymer matrices containing nanostructures made in the high‐temperature copolymerization resulted in channels for PEG and facile migration of drugs. In drug encapsulation or drug‐loading process, one can easily ignore or pay less attention to the interaction between a drug and its encapsulation materials; however, the ignored interactions may induce problems in drug properties or the release behavior in use. Sodium diclofenac (DFNa) precipitates as the carboxylic acid form in an acidic environment, and it is challenging to encapsulate sodium diclofenac in such an acidic matrix without precipitation of the sparingly soluble acid form of DFNa on the surface of the polymer substrate. To avoid bulky precipitation in drug loading, an in situ loading technique was developed for producing gel spheres with DFNa uniformly distributed in the polymer matrix. The technique is based on fast polymerization of spherical droplets of a pregel solution in which the drug is dissolved. Diffusion‐loading prodrugs were made in comparison with in situ loading prodrugs in thermal, release kinetics, and release behavior. Drug release profiles (in pH 7.4 phosphate buffer) show that the new drug loading technique gives controlled release during a period of about 7 days at 37°C. By contrast, gel spheres loaded with sodium diclofenac using the conventional diffusion technique produced almost total release of the drug within about 24 h. The thermal stability of sodium diclofenac, the PEG/AMPS‐co‐NIPA SIPN, and the prodrugs made with the SIPN and sodium diclofenac was studied. A near zero‐order release kinetics was found in the in vitro release of sodium diclofenac with in situ loading PEG SIPN prodrug. We have, for the first time, studied sodium diclofenac release behavior from the PEG SIPN hydrogel systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
High thermal conductive epoxy molding compound with thermal conductive pathway
Authors: Zeng Jun , Fu Renli , Shen Yuan , He Hong , Song Xiufeng
Published: April 2009

The epoxy molding compound (EMC) with thermal conductive pathways was developed by structure designing. Three kinds of EMCs with different thermal conductivities were used in this investigation, specifically epoxy filled with Si3N4, filled with hybrid Si3N4/SiO2, and filled with SiO2. Improved thermal conductivity was achieved by constructing thermal conductive pathways using high thermal conductivity EMC (Si3N4) in low thermal conductivity EMC (SiO2). The morphology and microstructure of the top of EMC indicate that continuous network is formed by the filler which anticipates heat conductivity. The highest thermal conductivity of the EMC was 2.5 W/m K, reached when the volume fraction of EMC (Si3N4) is 80% (to compare with hybrid Si3N4/SiO2 filled‐EMC, the content of total fillers in the EMC was kept at 60 vol %). For a given volume fraction of EMC (Si3N4) in the EMC system, thermal conductivity values increase according to the order EMC (Si3N4) particles filled‐EMC, hybrid Si3N4/SiO2 filled‐EMC, and EMC(SiO2) particles filled‐EMC. The coefficient of thermal expansion (CTE) decreases with increasing Si3N4 content in the whole filler. The values of CTE ranged between 23 × 10−6 and 30 × 10−6 K−1. The investigated EMC samples have a flexural strength of about 36–39 MPa. The dielectric constant increases with Si3N4 content but generally remains at a low level (<6, at 1 MHz). The average electrical volume resistivity of the EMC samples are higher than 1.4 × 1010 Ω m, the average electrical surface resistivity of the EMC samples are higher than 6.7 × 1014 Ω. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of poly(vinyl alcohol) nanocomposites made from cellulose nanofibers
Authors: Qua E. H. , Hornsby P. R. , Sharma H. S. S , Lyons G. , McCall R. D.
Published: April 2009

A method using a combination of ball milling, acid hydrolysis, and ultrasound was developed to obtain a high yield of cellulose nanofibers from flax fibers and microcrystalline cellulose (MCC). Poly(vinyl alcohol) (PVA) nanocomposites were prepared with these additives by a solution‐casting technique. The cellulose nanofibers and nanocomposite films that were produced were characterized with Fourier transform infrared spectrometry, X‐ray diffraction, thermogravimetric analysis, scanning electron microscopy, and transmission electron microscopy. Nanofibers derived from MCC were on average approximately 8 nm in diameter and 111 nm in length. The diameter of the cellulose nanofibers produced from flax fibers was approximately 9 nm, and the length was 141 nm. A significant enhancement of the thermal and mechanical properties was achieved with a small addition of cellulose nanofibers to the polymer matrix. Interestingly, the flax nanofibers had the same reinforcing effects as MCC nanofibers in the matrix. Dynamic mechanical analysis results indicated that the use of cellulose nanofibers (acid hydrolysis) induced a mechanical percolation phenomenon leading to outstanding and unusual mechanical properties through the formation of a rigid filler network in the PVA matrix. X‐ray diffraction showed that there was no significant change in the crystallinity of the PVA matrix with the incorporation of cellulose nanofibers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Crack‐healing behavior of epoxy–amine thermosets
Authors: Rahmathullah M. Aflal M. , Palmese Giuseppe R.
Published: April 2009

This work offers detailed experimental evidence for crack healing in fully formed epoxy–amine polymer networks. Compact tension specimens of diglycidyl ether of bisphenol A (EPON‐828) and 4,4′‐methylene biscyclohexanamine were synthesized at stoichiometry and with an excess or paucity of an amine curing agent. Healing efficiencies were measured on the basis of the regain in the fracture load after a healing protocol was applied. For all systems investigated, the average healing efficiency for first fracture was greater than 50% when healing was conducted at 185°C for 1 h. The crack‐healing behavior was highly repeatable at all stoichiometries, and healing was found to occur for repeated fracture–heal cycles of the same specimen. On the basis of results from size exclusion chromatography for the extractable phase, infrared spectroscopy, and scanning electron microscopy, it is postulated that healing is primarily due to mechanical interlocking of the nodular topology of a fractured crack interface that occurs in the rubbery state and is set in place by vitrification upon cooling. A ½ power dependence of the healing efficiency on the healing time was observed, and this suggests that the interlocking of topographical features is governed by diffusive processes. For networks cured with a large excess of epoxide groups, the recovered fracture load was higher than that of virgin specimens. In this case, polyetherification or homopolymerization of previously unreacted epoxy groups increased the healing efficiency significantly, and this suggests that low degrees of covalent bonding can significantly enhance healing behavior in these systems. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and properties of aromatic polyimide, poly(benzoxazole imide), and poly(benzoxazole amide imide)
Authors: Wu Sheng‐Yen , Yuen Siu‐Ming , Ma Chen‐Chi M. , Huang Yuan‐Li
Published: April 2009

Two series of heterocyclic aromatic polymers were synthesized from 4,4′‐(4,4′‐isopropylidenediphenoxy)bis(phthaltic anhydride) and 2,2′‐bis(3,4‐dicarboxyphenyl)hexafluoropropane dianhydride by two‐step method. The inherent viscosities were in the range of 24–45 cm3/g. The effects of the rigid benzoxazole group in the backbone of copolymer on the thermal, mechanical, and physical properties were investigated. These polymers exhibit good thermal stability. The temperatures of 5% weight loss (T5) of these polymers are in the range of 403–530°C in air and 425–539°C in nitrogen. The chard yields of these polymers are in the range of 15–24% in air and 54–61% in nitrogen. These polymers also have high glass‐transition temperatures and a low coefficient of thermal expansion and good mechanical properties. The poly(benzoxazol imide) has a higher tensile strength and modulus than those of neat polyimide. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Incorporation of lead phthalocyanine into periodic nanolayered assemblies for advanced optical systems
Authors: Armstrong Shannon , Zhou Zheng , Hiltner Anne , Baer Eric
Published: April 2009

Periodically structured polymeric materials can lead to the next generation of electro‐optic and nonlinear optical devices for applications in information technology. Layer‐multiplying melt coextrusion is an attractive method for fabricating periodic structures with thousands of alternating polymer microlayers or nanolayers. Many advanced applications for periodic polymeric structures would be enabled by locating a photoactive dye in one or both layers. However, it is anticipated that due to the thinness of the individual layers and the relatively low molecular weight of many dyes, a substantial fraction of the dye will diffuse from the doped layers into the undoped layers during melt coextrusion. In the present study, we demonstrate two methods for confining the activity of a photoactive dye, lead phthalocyanine, to the doped layers. Polycarbonate containing lead phthalocyanine was coextruded with undoped polyester as an assembly of 128 alternating 86 nm‐thick layers. Using the absorption spectra, we demonstrated that a high concentration of the monomer form persisted in the polycarbonate layers, whereas the lead form was converted to the less active lead‐free form in the polyester layers. Thus, the active monomer form of PbPc(β‐CP)4 was maintained selectively in the polycarbonate layers. In the second approach, the coextrusion process was altered so that the alternating polycarbonate and polyester layers were separated by a thin layer of a barrier polymer. The barrier layer prevented diffusion of the dye during melt coextrusion and the dye remained selectively in the polycarbonate layers. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Polysiloxane‐lignin composites
Authors: Stiubianu George , Cazacu Maria , Cristea Mariana , Vlad Angelica
Published: April 2009

A series of composites based on polydimethylsiloxane‐α,ω‐diol (PDMS) as polymeric matrix, silica aerogel as reinforcing filler, and the lignin powder—a biomass derivative, as bulking filler, have been prepared. Different weight ratios between components were used. The composites were investigated by scanning electron microscopy, dynamic mechanical analysis, tensile strength tests, X‐ray diffraction analysis, thermogravimetric analysis, and differential scanning calorimetry. The results were compared with those obtained on a reference sample prepared by using a classical material—diatomite and a pure crosslinked PDMS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of activation process and active site of co‐based catalyst for 1, 3‐butadiene polymerization using X‐ray absorption spectroscopy and DFT calculations
Authors: Kwag Gwanghoon , Bae Chulbeom , Kim Sunghyun
Published: April 2009

Activation process and active site of Co‐based Ziegler‐Natta catalysts were studied by using synchrotron X‐ray absorption spectroscopic technique and an optimum model of the cobalt active site was proposed with density functional theory (DFT) calculations. In the X‐ray absorption near edge structure (XANES) spectrum of Co(2‐ethylhexanoate)2, the preedge peak, 1s → 3d transition at 7707.8 eV and the K‐edge peak, 1s → 4p transition at 7719.2 eV were observed. Both the intense K‐edge and the weak preedge peaks indicate that Co(2‐ethylhexanoate)2 possesses high Oh symmetry and the cobalt exists in a divalent state. Upon addition of methylaluminoxane (MAO), some changes in peak positions and intensities were observed. The preedge peak was a little shifted to 7708.2 eV with increased intensity, and the K‐edge peak was shifted to a lower energy, 7717.2 eV with decreased intensity. This indicates that the oxidation state of cobalt still mainly remained +2 and the coordination geometry was altered from Oh to Td resulting from Co 3d and 4p orbital mixing with a loss of Oh symmetry. In the XANES spectrum of a mixture of Co(2‐ethylhexanoate)2, MAO and t‐BuCl, the K‐edge peak at 7715.7 eV was observed. The orbital mixing of 4p cobalt and 2p chlorine orbitals results in a low energy transition. In 1,3‐butadiene polymerization, this is attributable to the coordination of chlorine to cobalt, which is believed to facilitate cis‐configuration and increasing reactivity. B(C6F5)3 was employed as Lewis acid, but no significant interaction with cobalt was found in the XANES spectrum of a mixture of Co(2‐ethylhexanoate)2, Al(iBu) and B(C6F5)3, which is similar to the XANES of a mixture of Co(2‐ethylhexanoate)2 and Al(iBu)3. B(C6F5)3 as Lewis acid does not greatly disturb the coordination symmetry of cobalt nor influence the oxidation state. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
m/p‐Cresol–based t‐BOC protected alternating “high ortho” copolymer as a possible e‐beam resist: Characterization using multidimensional NMR spectroscopy
Authors: Sharma Maneesh , Hopson Russell , Raghunathan P. , Eswaran S. V.
Published: April 2009

Synthesis of a m/p‐cresol–based novolac resin and its subsequent esterification using di‐tert‐butyl dicarbonate (t‐BOC) is described. The product has been characterized using techniques of FTIR spectroscopy, one dimensional 1H NMR, 13C NMR, and DEPT‐135 spectra. Two dimensional NMR experiments like, COSY, HSQC, and HMBC have been used for exhaustive probing of the microstructural details of the derivatized copolymer. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Solution blow spinning: A new method to produce micro‐ and nanofibers from polymer solutions
Authors: Medeiros Eliton S. , Glenn Gregory M. , Klamczynski Artur P. , Orts William J. , Mattoso Luiz H. C.
Published: April 2009

A solution blow spinning technique was developed using elements of both electrospinning and melt blowing technologies as an alternative method for making non‐woven webs of micro‐ and nanofibers with diameters comparable with those made by the electrospinning process with the advantage of having a fiber production rate (measured by the polymer injection rate) several times higher. The diameters of fibers produced ranged from 40 nm for poly(lactic acid) to several micrometers for poly(methyl methacrylate). This solution blow spinning method uses a syringe pump to deliver a polymer solution to an apparatus consisting of concentric nozzles whereby the polymer solution is pumped through the inner nozzle while a constant, high velocity gas flow is sustained through the outer nozzle. Analysis of the process showed that pressure difference and shearing at the gas/solution interface jettisoned multiple strands of polymer solution towards a collector. During flight, the solvent component of the strands rapidly evaporates forming a web of micro and nanofibers. The effect of injection rate, gas flow pressure, polymer concentration, working distance, and protrusion distance of the inner nozzle was investigated. Polymer type and concentration had a greater effect on fiber diameter than the other parameters tested. Injection rate, gas flow pressure, and working distance affected fiber production rate and/or fiber morphology. Fibers were easily formed into yarns of micro‐ and nanofibers or non‐woven films that could be applied directly onto biological tissue or collected in sheets on a rotating drum. Indeed, virtually any type of target could be used for fiber collection. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Phase behavior of a sodium dodecanol allyl sulfosuccinic diester/n‐pentanol/methyl acrylate/butyl acrylate/water microemulsion system and preparation of acrylate latexes by microemulsion polymerization
Authors: Hu Aixi , Yao Zhigang , Yu Xi
Published: April 2009

Pseudoternary phase diagrams of quaternary microemulsion systems composed of the reactive surfactant sodium dodecanol allyl sulfosuccinic diester, n‐pentanol, methyl acrylate/butyl acrylate, and water were made. The influence of the mass ratio of sodium dodecanol allyl sulfosuccinic diester to the cosurfactant (n‐pentanol) in the system and the influence of electrolyte sodium chloride on the microemulsion area were examined. The microstructure of the microemulsion was determined with a conductance technique. The results suggested that there were three structures in the microemulsion system: water in oil, oil in water, and a bicontinuous phase. Microemulsion polymerizations were carried with some point in the microemulsion region being chosen as the formulation. The structure and configuration of the polymer latexes were determined and analyzed with Fourier transform infrared, differential scanning calorimetry, and scanning electron microscopy. The results suggested that the reactive surfactant could participate in the polymerization with the monomers to some extent; the glass‐transition temperature of the latex was −31.4°C. The polymer latex was transformed gradually from an open porous structure to a closed porous structure when its pregnant microemulsion was varied from a bicontinuous structure to an oil‐in‐water structure. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Graft copolymerization of 4‐vinyl pyridine onto konjac glucomannan initiated by ammonium persulfate
Authors: Liu Changhua , Dai Xun , Chen Jianguang , Chen Yanqing , Guo Xiaoli , Huang Yuming
Published: April 2009

The grafting of 4‐vinyl pyridine (4‐VP) onto konjac glucomannan (KGM) by ammonium persulfate (APS) as the initiator was studied in an acid aqueous solution under an inert atmosphere. The grafting ratio (G%) and grafting efficiency (E%) were evaluated comparatively. The dependence of these parameters on the initiator concentration, sulfuric acid concentration, ratio of monomer to KGM, temperature, and reaction time was also investigated. Under conditions of [KGM] = 1.00 g/L, [APS] = 1.00 × 10−2 mol/L, [4‐VP] = 9.32 × 10−2 mol/L, [H+] = 5.00 × 10−2 mol/L, temperature = 35°C, and time = 120 min, the optimum G% and E% were 307.27 and 52.75%, respectively. The proof of grafting was obtained from thermogravimetric analysis and infrared spectra. Preliminary research of the graft's adsorption capacity for heavy‐metal ions [Cr(VI), Cu(II), Pb(II), and Cd(II)] was done. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Potential for desalination using lower critical solution temperature polymers: Concentration of salt solutions by pluronic PE6200
Authors: Maurdev George , Millington Keith R.
Published: April 2009

A commercially available lower critical solution temperature (LCST) polymer was demonstrated to preferentially adsorb water containing a reduced ion concentration, from CrCl3 salt solutions and release some of this scavenged water at higher temperatures. The scavenging ability of the polymer was demonstrated to be dependent on the bulk salt concentration. The volume of water scavenged and the concentration of the remaining CrCl3 solution increased linearly with the amount of LCST polymer (Pluronic PE 6200) used. Both the volume of water removed and the amount by which the remaining CrCl3 solution was concentrated decreased with increasing CrCl3 concentration. Implications for research into a novel method for sea water desalination are addressed. We also show water extraction from dilute sodium chloride and sea water, and that these results are consistent with the CrCl3 model system. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Study of crosslinking of polyphosphazene with allyl pendant groups initiated by benzoyl peroxide
Authors: Huang Yawen , Pan Yang , Fu Jianwei , Huang Xiaobin , Tang Xiaozhen
Published: April 2009

A selected polyorganophosphazene containing three substituents: phenoxy group, 2‐allylphenoxy group, and ethoxy group, had been thermally cross‐linked. The polymer can be crosslinked at 85°C which was lower than the general reported operation temperature. The transformation of chemical structure was analyzed by FTIR technique. It was found that oxidization caused the formation of peroxides, ether and ester during crosslinking. The effect of different conditions including time, temperature, and initiator on properties of crosslinked polymer had been studied. The change of properties was well consistent with the change of chemical structure including vinyl and peroxide. Detailed cross‐linking mechanisms were proposed based on FTIR spectra by monitoring the possible association sites. It was suggested that the initiation reaction preferentially occurred at methylene but not vinyl, and major linkages between polymer chains were ether and peroxide bonds. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and biocidal efficacy of self‐spreading polydimethylsiloxane oligomers possessing oxyethylene‐functionalized quaternary ammoniums
Authors: Pant Ramesh R. , Fulmer Preston A. , Harney Matthew B. , Buckley Joseph P. , Wynne James H.
Published: April 2009

In an effort to develop a more versatile creeping biocide that is capable of self‐spreading and self‐decontaminating of pathogenic bacteria, we report the development of two new homologous series of hybrid PDMS molecules. These oligomers were synthesized with terminal quaternary ammonium functionalities bearing variable length oxyethylene moieties. It is shown that the ionic interaction of the ammonium groups with the surface onto which it spreads can be tempered by the oxyethylene segments through close association of the polar chains with the cationic centers within the hydrophobic PDMS environment, thereby promoting self‐spreading of the molecule. Once the compounds spread to a humid environment, the oxyethylene chains “blossom” and subsequently expose the biocidal centers, at which point, function as broad spectrum versatile antimicrobials. While biological evaluation showed antimicrobial activity against both Gram‐positive and Gram‐negative bacteria for all samples, one series was found to be much more effective due to lower steric hindrance surrounding the biocidal cationic termini. However, this increased exposure of the cationic center also altered the physical properties of the compounds except those isolated as a waxy solid. Self‐spreading abilities with increasing oxyethylene chain length correlating to a decreasing spread rate. The decontaminating ability of the two most active compounds was demonstrated by allowing samples to spread to pools of water contaminated with S. aureus, yielding log reductions as high as 5.7 in less than two hours without external influences. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties of the flexible‐type epoxy/clay nanocomposites prepared by slurry method
Authors: Harada Miyuki , Ueda Ayumu , Miyazaki Hironori , Ochi Mitsukazu
Published: April 2009

The bisphenol‐F type flexible epoxy resin, having a good flexibility, was combined with an organo‐ and slurry‐clay. The clay dispersions in the obtained epoxy/clay systems are significantly different depending on the type of clay. Particularly, the epoxy/slurry‐clay system showed a high clay dispersibility into the epoxy matrix and was transparent in spite of the addition of 10 wt % clay. This result means that the swelling of the clay with formamide is effective for the expansion of the basal spacing of the clay. The slurry‐clay nanocomposite (clay content: 5 wt %) showed a 4 times higher fracture energy than the neat epoxy system in the tensile test, though the organo‐clay system (clay content: 5 wt %) was 1.5 times higher. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
The microstructure of polyacrylonitrile‐stabilized fibers
Authors: Ge Heyi , Liu Huashi , Chen Juan , Wang Chengguo
Published: April 2009

The microstructure of the polyacrylonitrile (PAN)‐stabilized fibers was investigated by X‐ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), and high‐resolution transmission electron microscope (HRTEM). XRD analysis indicated that the chemical reactions sped up notably when temperature was above 250°C. The crosssection SEM image of the stabilized fibers presented concentric multilayer morphology. TEM images showed that the lamellar‐like skin was compact and the core was disorderly and loose. The vermiculate‐like crystallites in the precursor fibers were transferred to spheres during stabilization process. HRTEM images showed that many spheres existed in the stabilized fibers. The exterior of spheres which had annular structure was amorphous phase. The inner of spheres which was not completely stabilized had some crystallite areas. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Self‐report of physical symptoms associated with using mobile phones and other electrical devices
Authors: Korpinen Leena H. , Pääkkönen Rauno J.
Published: April 2009

The aim of our work was to study the working‐age population's self‐reported physical symptoms associated with using mobile phones and other electrical devices. A qualitative method was applied using an open‐ended question in a questionnaire, which included questions about the possible influence of new technical equipment on health. We then created subgroups of respondents for different self‐reported symptoms associated with mobile phones and other electrical devices. The research questions were: (1) how the respondents described physical symptoms associated with using mobile phones and other electrical devices and (2) how the answers can be classified into subgroups based on symptoms or devices. We identified the following categories: (1) respondents with different self‐reported symptoms which they associated with using mobile phones (headache, earache, or warmth sensations), (2) respondents who had skin symptoms when they stayed in front of a computer screen, (3) respondents who mentioned physical symptoms associated with using mobile phones and other electrical devices. Total prevalence of self‐reported physical symptoms associated with using mobile phones and other electrical devices (categories 1 and 2) was 0.7%. In the future it will be possible to obtain new knowledge of these topics by using qualitative methods. Bioelectromagnetics 30:431–437, 2009. © 2009 Wiley‐Liss, Inc.
Beurteilung der Tragfähigkeit von geschädigten Stahlbetonbrücken auf der Grundlage der Ergebnisse einer Bauwerksprüfung
Authors: Braml Thomas , Keuser Manfred
Published: April 2009

Die regelmäßig stattfindenden Brückenprüfungen haben für die sichere Nutzung von Brückenbauwerken eine hohe Bedeutung. Der folgende Beitrag zeigt ein Verfahren, das den Bauwerksprüfer bei der Einschätzung der Tragfähigkeit von geschädigten Stahlbetonbrücken noch während bzw. unmittelbar nach einer Bauwerksprüfung unterstützt. Auf der Grundlage dieser ersten Einschätzung kann vor einer Objektbezogenen Schadensanalyse über eventuell einzuleitende Sofortmaßnahmen wie z. B. die Reduktion der zulässigen Verkehrslasten entschieden werden. Mit Näherungsverfahren der Zuverlässigkeitstheorie der 1. und 2. Ordnung (FORM und SORM) wird unter Berücksichtigung der Schädigung der Zuverlässigkeitsindex, bzw. die Versagenswahrscheinlichkeit pf des Bauwerks berechnet. Der Beitrag zeigt das Vorgehen sowie die Anwendung an einem Beispiel. Insbesondere im kommunalen Bereich ist das Verfahren hilfreich, da hier nicht in allen Fällen davon ausgegangen werden kann, dass regelmäßige Bauwerksprüfungen und entsprechende Unterhaltungsmaßnahmen durchgeführt worden sind.
Entwurf von Flüssigkeitsbehältern
Authors: Buschmeyer Wilhelm , Eßer Angelika
Published: April 2009

In der WU‐Richtlinie des Deutschen Ausschusses für Stahlbeton werden Anforderungen an die Gebrauchstauglichkeit von wasserundurchlässigen Bauwerken aus Beton geregelt. Die Richtlinie gilt auch für Flüssigkeitsbehälter, deren wesentliche Eigenschaft ihre definierte Dichtheit ist. Ausgehend von den Entwurfsgrundsätzen der Richtlinie und bisher gemachten Praxiserfahrungen werden Konzepte für die Auslegung von Behältern in Betonbauweise diskutiert. Darüber hinaus werden Grundsätze für mäßig vorgespannte Stahlbetonbehälter mit einer dauerhaften Füllung planmäßiger Trennrisse vorgestellt. Auf Aspekte einer Bemessung nach der Europäischen Norm EC 2 Teil 3 wird hingewiesen.
Erfahrungen mit massigen Bauteilen beim Bau der Schleuse Lauenburg
Authors: Morgen Karl , Lühr Stefan
Published: April 2009

Lauenburg ist ein historischer Schleusenstandort, der bereits im 14. Jahrhundert durch die Palmschleuse den Salzhandel zur Ostsee auf dem Wasserwege ermöglichte. In dieser Zeit entwickelte sich die Stecknitzfahrt auf dem Ende des 14. Jahrhunderts erbauten Stecknitzkanal, der Ende des 19. Jahrhunderts durch den Elbe‐Trave‐Kanal bzw. Elbe‐Lübeck‐Kanal ersetzt wurde. Bis heute ist die Schifffahrt in diesem Bereich bedeutsam und seit 2006 sichert die neue Schleuse Lauenburg den modernen Schifffahrtsverkehr zwischen Elbe und Ostsee. Die neue Schleuse Lauenburg ist ein Ersatzneubau für die 1900 gebaute alte Schleuse und wurde in fünf Jahren Bauzeit in Stahlbetonbauweise errichtet. Für die erforderlichen Festlegungen zur Mindestbewehrung nach ZTV‐W215 und für die risssteuernde Bewehrung bei massigen Bauteilen wurde in Abstimmung mit dem Auftraggeber, dem Auftragnehmer und dem beauftragten Prüfingenieur ein pragmatischer Ansatz gewählt.

Frei nach William James “Wahr ist das, was sich durch seine praktischen Konsequenzen bewährt.”
Biomanufacturing process analytical technology (PAT) application for downstream processing: Using dissolved oxygen as an indicator of product quality for a protein refolding reaction
Authors: Pizarro Shelly A. , Dinges Rachel , Adams Rachel , Sanchez Ailen , Winter Charles
Published: April 2009

Process analytical technology (PAT) is an initiative from the US FDA combining analytical and statistical tools to improve manufacturing operations and ensure regulatory compliance. This work describes the use of a continuous monitoring system for a protein refolding reaction to provide consistency in product quality and process performance across batches. A small‐scale bioreactor (3 L) is used to understand the impact of aeration for refolding recombinant human vascular endothelial growth factor (rhVEGF) in a reducing environment. A reverse‐phase HPLC assay is used to assess product quality. The goal in understanding the oxygen needs of the reaction and its impact to quality, is to make a product that is efficiently refolded to its native and active form with minimum oxidative degradation from batch to batch. Because this refolding process is heavily dependent on oxygen, the % dissolved oxygen (DO) profile is explored as a PAT tool to regulate process performance at commercial manufacturing scale. A dynamic gassing out approach using constant mass transfer (kLa) is used for scale‐up of the aeration parameters to manufacturing scale tanks (2,000 L, 15,000 L). The resulting DO profiles of the refolding reaction show similar trends across scales and these are analyzed using rpHPLC. The desired product quality attributes are then achieved through alternating air and nitrogen sparging triggered by changes in the monitored DO profile. This approach mitigates the impact of differences in equipment or feedstock components between runs, and is directly inline with the key goal of PAT to “actively manage process variability using a knowledge‐based approach.” Biotechnol. Bioeng. 2009; 104: 340–351 © 2009 Wiley Periodicals, Inc.
Determination of tryptophan in bee pollen and royal jelly by high‐performance liquid chromatography with fluorescence detection
Authors: Zhang Jin‐zhen , Xue Xiao‐feng , Zhou Jin‐hui , Chen Fang , Wu Li‐ming , Li Yi , Zhao Jing
Published: April 2009

A method for tryptophan analysis in bee pollen and royal jelly was developed using HPLC with fluorescence detection. To determine the free tryptophan in bee pollen and royal jelly, ultrasonic extraction was performed using water (pH 6.3)–acetonitrile (10:1, v/v) as extraction solvent. While determining the total tryptophan in these bee products, the method involves alkaline hydrolysis of the proteins with 4 mol/L sodium hydroxide at 110°C for 20 h under anaerobic conditions. The operating conditions for the HPLC analysis were: Symmetry C18 column (4.6 × 250 mm, 5 µm), 0.1% trifluoroacetic acid–methanol (75:25, v/v) as the mobile phase at a flow rate of 1.0 mL/min at 30°C. The fluorescence detector was operated at an excitation wavelength of 280 nm and an emission wavelength of 340 nm. A linear response (r2 > 0.9998) was obtained in the range 0.0625–5.0 µg/mL. The method was successfully applied to the determination of the free and total tryptophan contents in bee pollens, which were 0.069 ± 0.003 and 2.693 ± 0.476 mg/g, respectively, while only the total tryptophan was detected in royal jelly, with a content of 1.743 ± 0.066 mg/g. Copyright © 2009 John Wiley & Sons, Ltd.
The Natural Products Beauveriolide I and III: a New Class of β‐Amyloid‐Lowering Compounds
Authors: Witter Daniel P. , Chen Yanping , Rogel Joseph K. , Boldt Grant E. , Wentworth Paul
Published: April 2009

Attacking Alzheimer's by ACAT: The aggregation of β‐amyloid peptides, especially Aβ42, into senile plaques is a hallmark of Alzheimer's disease (AD). We show that the fungal natural products beauveriolides I and III can potently decrease Aβ secretion from cells expressing human amyloid precursor protein; this offers a potential new scaffold for the development of compounds with proven bioavailability for the treatment of AD.

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