bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Calcium Gluconate Concentration and Hydrodynamic Effect on Mild Steel Corrosion Inhibition in Simulated Cooling Water
Authors: Saremi M. , Benehkohal N. Parsi , Dehghanian C. , Zebardast H. R.
Published: February 2010

The effects of two important factors, namely concentration and hydrodynamics on the inhibition efficiency of calcium gluconate (C12H22CaO14), were investigated using potentiodynamic polarization and electrochemical impedance spectroscopy tests. Results showed that calcium gluconate was capable of inhibiting the corrosion of mild steel in simulated cooling water. The inhibition efficiency of calcium gluconate was increased by increasing its concentration and decreased by increasing water circulation velocity due to the adsorption process, which leads to the formation of a protective layer with a greater charge-transfer resistance on the metal surface. The hydrodynamic effect seems to promote the adsorption of calcium gluconate on the metal surface, which was confirmed by the fitting of the Langmuir adsorption isotherm.
Protective Coatings Offshore: Introducing a Risk-Based Maintenance Management System—Part 1: Risk Analysis Methodology
Authors: Axelsen S. B. , Knudsen O. Ø. , Johnsen R.
Published: February 2010

This paper summarizes the risk analysis methodology and challenges related to the establishment of a risk-based maintenance management system for protective coatings. Maintenance of protective coatings offshore is demanding on resources and costly. Initial selection of a coating system and the quality of the application work, including surface preparation, are vital elements for securing an acceptable coating lifetime. Most offshore installations will require, however, maintenance of the protective coatings due to degradation and/or mechanical damages. Development and implementation of a maintenance program for coatings is therefore an essential part of the overall maintenance programfor these installations. A complete maintenance program development includes: 1) establishment of coating quality status through inspection, 2) preparation of a maintenance program/strategy, and 3) preparation of detailed maintenance plans and job packages/descriptions. Optimization of maintenance and inspection programs through risk analysis is used frequently by the industry today. This principle can also be used for coating maintenance. Since the risk picture can be described by scenario, frequencies, and consequences, risk could be expressed as a function of coating status and a consequence of a coating damage. Based on this assumption, a systematic approach for optimization of the maintenance program has been developed.
Metastable Austenite in 17–4 Precipitation‐Hardening Stainless Steel Produced by Selective Laser Melting
Authors: Facchini Luca , Vicente Nério , Lonardelli Ivan , Magalini Emanuele , Robotti Pierfrancesco , Molinari Alberto
Published: February 2010

A 17–4 precipitation‐hardening stainless steel produced by selective laser melting contains 72% metastable and heavily faulted austenite and 28% highly dislocated and twinned martensite. The mechanical behavior is characterized by exceptional work hardening and a two‐step plastic field, which are due to the strain‐induced transformation of austenite and to the structural characteristics of the deformed austenite and martensite. Both phases tend to accumulate stacking faults in the first step and twins in the second.
Quantum‐Dot‐Tagged Bioresponsive Hydrogel Suspension Array for Multiplex Label‐Free DNA Detection
Authors: Zhao Yuanjin , Zhao Xiangwei , Tang Baocheng , Xu Wenyu , Li Juan , Hu Jing , Gu Zhongze
Published: February 2010

A novel hydrogel suspension array, which possesses the joint advantages of quantum‐dot‐encoded technology, bioresponsive hydrogels, and photonic crystal sensors with full multiplexing label‐free DNA detection capability is developed. The microcarriers of the suspension array are quantum‐dot‐tagged DNA‐responsive hydrogel photonic beads. In the case of label‐free DNA detection, specific hybridization of target DNA and the crosslinked single‐stranded DNA in the hydrogel grid will cause hydrogel shrinking, which can be detected as a corresponding blue shift in the Bragg diffraction peak position of the beads that can be used for quantitatively estimating the amount of target DNA. The results of the label‐free DNA detection show that the suspension array has high selectivity and sensitivity with a detection limit of 10−9 M. This method has the potential to provide low cost, miniaturization, and simple and real‐time monitoring of hybridization reaction platforms for detecting genetic variations and sequencing genes.
Fully Transparent Non‐volatile Memory Thin‐Film Transistors Using an Organic Ferroelectric and Oxide Semiconductor Below 200 °C
Authors: Yoon Sung‐Min , Yang Shinhyuk , Byun Chunwon , Park Sang‐Hee K. , Cho Doo‐Hee , Jung Soon‐Won , Kwon Oh‐Sang , Hwang Chi‐Sun
Published: February 2010

A fully transparent non‐volatile memory thin‐film transistor (T‐MTFT) is demonstrated. The gate stack is composed of organic ferroelectric poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)] and oxide semiconducting Al‐Zn‐Sn‐O (AZTO) layers, in which thin Al2O3 is introduced between two layers. All the fabrication processes are performed below 200 °C on the glass substrate. The transmittance of the fabricated device was more than 90% at the wavelength of 550 nm. The memory window obtained in the T‐MTFT was 7.5 V with a gate voltage sweep of −10 to 10 V, and it was still 1.8 V even with a lower voltage sweep of −6 to 6 V. The field‐effect mobility, subthreshold swing, on/off ratio, and gate leakage currents were obtained to be 32.2 cm2 V−1 s−1, 0.45 V decade−1, 108, and 10−13 A, respectively. All these characteristics correspond to the best performances among all types of non‐volatile memory transistors reported so far, although the programming speed and retention time should be more improved.
Hypoventilation in REM sleep in a case of 17p11.2 deletion (Smith–Magenis syndrome)
Authors: Leoni Chiara , Cesarini Laura , Dittoni Serena , Battaglia Domenica , Novelli Antonio , Bernardini Laura , Losurdo Anna , Vollono Catello , Testani Elisa , Marca Giacomo Della , Zampino Giuseppe
Published: February 2010

We describe a 2‐year‐old baby affected by Smith–Magenis syndrome (SMS), due to 17p11.2 deletion, who presented repeated episodes of hemoglobin desaturation during REM sleep. The boy, aged 14 months, presented a phenotype characterized by psychomotor delay, right posterior plagiocephaly, telecanthus, strabismus, upslanting palpebral fissures, broad hypoplastic nasal bridge, short philtrum, deep ring shaped skin creases around the limbs, proximal syndactyly, bilateral hypoacusia. Polysomnographic (PSG) recording showed episodes of REM‐related hypoventilation (hemoglobin desaturations without apneas or hypopneas). Sleep disorders are present in almost all the cases of SMS, but very few reports describe the sleep‐related respiratory patterns. The finding of REM hypoventilation in SMS does not allow an unequivocal interpretation. It could reflect a subclinical restrictive respiratory impairment or, alternatively, an impairment of central respiratory control during REM sleep. In SMS children, respiratory abnormalities during sleep, and in particular during REM sleep, may cause sleep disruption, reduction of time spent in REM sleep, and daytime sleepiness. We therefore suggest that some sleep abnormalities described in SMS could be consequent to Sleep Disordered Breathing, and in particular to REM hypoventilation. Sleep studies in SMS should include the recording of respiratory parameters. © 2010 Wiley‐Liss, Inc.
Investigation of a patient with a partial trisomy 16q including the fat mass and obesity associated gene (FTO): Fine mapping and FTO gene expression study
Authors: van den Berg Linda , de Waal Henriette Delemarre‐van , Han Joan C. , Ylstra Bauke , Eijk Paul , Nesterova Maria , Heutink Peter , Stratakis Constantine A.
Published: February 2010

A female patient with a partial trisomy 16q was described previously. Her clinical characteristics included obesity, severe anisomastia, moderate to severe mental retardation, attention deficit hyperactivity disorder, dysmorphic facies, and contractions of the small joints. In this article, we describe a more detailed analysis of the genetic anomaly in this patient. We were particularly interested in the involvement of the fat mass and obesity associated gene (FTO) in her duplication. Single nucleotide polymorphisms in FTO have been associated with obesity. The breakpoints of the duplication were precisely mapped using high‐resolution oligonucleotide array comparative genomic hybridization (CGH). We found that the duplication spans 11.45 Mb on 16q11.2 to 16q13 and it includes FTO. The increased copy number of FTO was confirmed with a qPCR on genomic DNA of the patient. We investigated the influence of the increased FTO copy number on FTO gene expression in immortalized lymphocytes from the patient using qPCR. No evidence of increased FTO expression was detected in the patient's lymphocytes. We discuss these findings and we review clinical findings in patients with overlapping 16q duplications to determine the relationship between increased FTO copy number and obesity. Our review suggests that duplication of the FTO gene does not necessarily result in obesity. © 2010 Wiley‐Liss, Inc.
Prenatal diagnosis of a recombinant chromosome 7 resulting in trisomy 7q11.22 → qter
Authors: Tchirikov M. , Merinsky A. , Strohner M. , Bonin M. , Beyer V. , Haaf T. , Bartsch O.
Published: February 2010

Prenatal diagnosis of trisomy 7 is complex due to only a few reported cases. We report here on a stillborn boy with very large duplication of 7q11.22 → qter, encompassing almost the entire long arm of chromosome 7. Ultrasound, fetal and parental chromosome banding, fluorescence in situ hybridization (FISH), and array comparative genomic hybridization (CGH) analyses were performed. Sonographic findings included growth retardation, micrognathia, ventricular septal defect (VSD), aortic coarctation, bradyarrhythmia, pericardial effusion, bilateral hydronephrosis, infravesical obstruction, and cerebellar hypoplasia. Chromosome analysis after cordocentesis at 23 weeks of gestation revealed an abnormal male karyotype with 46 chromosomes and a derivative chromosome 7 with a very large duplication of the long arm, 46,XY,der(7)(qter → q11.2::p22 → qter). The mother was found to carry an apparently balanced pericentric inversion, 46,XX,inv(7)(p22q11.2). Thus, the recombinant chromosome 7 [rec(7)dup(7q)inv(7)(p22.3q11.22)mat] of the fetus must have arisen through meiotic crossing‐over between the inverted chromosome and the normal chromosome 7 in the maternal germline. FISH and array CGH results confirmed the recombinant chromosome 7 in the fetus and indicated a loss of 1.9 Mb at chromosome 7pter → p22.3 (pter to 1,948,072 bp), and a gain of 87.04 Mb at chromosome 7q11.22 → qter (71,760,154 bp to qter). The rare syndrome of almost complete trisomy 7q may be suspected in cases of growth retardation, cerebellar hypoplasia, micrognathia, aortic coarctation and VSD and hydronephrosis. Invasive prenatal diagnosis must be offered to the parents. © 2010 Wiley‐Liss, Inc.
22q13.3 deletion syndrome: Clinical and molecular analysis using array CGH
Authors: Dhar S.U. , del Gaudio D. , German J.R. , Peters S.U. , Ou Z. , Bader P.I. , Berg J.S. , Blazo M. , Brown C.W. , Graham B.H. , Grebe T.A. , Lalani S. , Irons M. , Sparagana S. , Williams M. , Phillips J.A. , Beaudet A.L. , Stankiewicz P. , Patel A. , Cheung S.W. , Sahoo T.
Published: February 2010

The 22q13.3 deletion syndrome results from loss of terminal segments of varying sizes at 22qter. Few genotype–phenotype correlations have been found but all patients have mental retardation and severe delay, or absence of, expressive speech. We carried out clinical and molecular characterization of 13 patients. Developmental delay and speech abnormalities were common to all and comparable in frequency and severity to previously reported cases. Array‐based comparative genomic hybridization showed the deletions to vary from 95 kb to 8.5 Mb. We also carried out high‐resolution 244K array comparative genomic hybridization in 10 of 13 patients, that defined the proximal and distal breakpoints of each deletion and helped determine the size, extent, and gene content within the deletion. Two patients had a smaller 95 kb terminal deletion with breakpoints within the SHANK3 gene while three other patients had a similar 5.5 Mb deletion implying the recurrent nature of these deletions. The two largest deletions were found in patients with ring chromosome 22. No correlation could be made with deletion size and phenotype although complete/partial SHANK3 was deleted in all patients. There are very few reports on array comparative genomic hybridization analysis on patients with the 22q13.3 deletion syndrome, and we aim to accurately characterize these patients both clinically and at the molecular level, to pave the way for further genotype–phenotype correlations. © 2010 Wiley‐Liss, Inc.
Primate cranial diversity
Authors: Fleagle John G. , Gilbert Christopher C. , Baden Andrea L.
Published: February 2010

Many studies in primate and human evolution focus on aspects of cranial morphology to address issues of systematics, phylogeny, and functional anatomy. However, broad analyses of cranial diversity within Primates as an Order are notably absent. In this study, we present a 3D geometric morphometric analysis of primate cranial morphology, providing a multivariate comparison of the major patterns of cranial shape change during primate evolution and quantitative assessments of cranial diversity among different clades. We digitized a set of 18 landmarks designed to capture overall cranial shape on male and female crania representing 66 genera of living primates. The landmark data were aligned using a Generalized Procrustes Analysis and then subjected to a principal components analysis to identify the major axes of cranial variation. Cranial diversity among clades was compared using multivariate measurements of variance. The first principal component axis reflects differences in cranial flexion, orbit size and orientation, and relative neurocranial volume. In general, it separates strepsirrhines from anthropoids. The second axis reflects differences in relative cranial height and snout length and primarily describes differences among anthropoids. Eulemur, Mandrillus, Pongo, and Homo are among the extremes in cranial shape. Anthropoids, catarrhines, and haplorhines show a higher variance than prosimians or strepsirrhines. Hominoids show the highest variance in cranial shape among extant primate clades, and much of this diversity is driven by the unique cranium of Homo sapiens. Am J Phys Anthropol 142:565–578, 2010. © 2010 Wiley‐Liss, Inc.
Comparison of ethylene‐propylene diene terpolymer composites filled with natural and synthesized micas
Authors: Wang Lei‐Lei , Tong Yun‐Peng , Zhang Li‐Qun , Tian Ming
Published: February 2010

In this paper, EPDM/mica composites were prepared by filling synthesized mica and natural mica separately into ethylene‐propylene diene terpolymer (EPDM) using melt blending technique. Microstructures, electrical properties, gas resistance, and mechanical properties of two EPDM/mica composites were investigated systematically. FTIR show that hydroxyl groups exist on the surface of the micas. These structural hydroxyls could be active sites conducive to the surface modification of mica. XRD analyses reveal that the natural mica is crystalline and the synthesized mica is amorphous. After being modified with silane coupling agent Si69, mica was only exfoliated into smaller micron agglomerates dispersing in EPDM, but the dispersion of amorphous synthesized mica was better. So the EPDM/synthesized mica composite possessed better mechanical property, electrical insulation property, and gas permeability resistance. It is expected that better improvement would be achieved, if mica is exfoliated further into nanosheets dispersing in the rubber matrix. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Potentialin situpreparation of aliphatic polyamide‐based nanocomposites: The organoclay‐polyamide salt interaction
Authors: Boussia A. C. , Damianou Ch. C. , Vouyiouka S. N. , Papaspyrides C. D.
Published: February 2010

In situintercalative polycondensation is applied for the preparation of polyamide (PA)n,6–clay nanocomposites, namely poly(ethylene adipamide) (PA 2,6), poly(hexamethylene adipamide) (PA 6,6), and poly(dodecamethylene adipamide) (PA 12,6). For this purpose, two different polymerization routes are considered; a low‐temperature melt polymerization technique and the conventional solution‐melt one. Under the specific experimental conditions, lack of clay exfoliation is detected through XRD measurements, which is proved irreversible even when twin‐screw extrusion is attempted as an additional step. The resulting PAn,6–clay structures are found dependent on the diamine moiety length; more specifically, an intrinsic interaction between the polyamide monomer and the organoclay surfactant is indicated. An ion exchange occurs between the two competitive species, that is, diamine and surfactant cations, leading to flocculated clay structures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Enzymatic hydrolysis of nylon 6 fiber using lipolytic enzyme
Authors: Kiumarsi Amir , Parvinzadeh Mazeyar
Published: February 2010

This study confirms the structural changes of nylon 6 fibers using lipase by measuring the dyeability, hydrophilicity, chemical changes, and fastness properties. For this purpose, nylon 6 fabrics were first treated separately with different concentrations of lipase enzyme. The dyeing process was then carried out on the treated fabrics with two disperse and acid dyes. A UV‐vis spectrophotometer was used for determination of dyebath exhaustion. Acid and disperse dyes showed higher dyebath exhaustion on the enzyme treated samples compared to raw material. The intensity of major peaks in FTIR spectra of the lipase treated samples are in favor of chemical changes of the polypeptide functional groups in fabric. Tensile strength of treated fabrics was decreased due to enzyme treatment. The results of color measurements in the CIELAB system showed that the darkness of the samples increased with an increase in the enzyme percentage in the solution. The results of moisture regain showed that treatment of nylon fabrics with lipolytic enzymes caused to increase the moisture absorbency. The wash and light fastness properties of samples were measured according to ISO 105‐CO5 and Daylight ISO 105‐BO1 and discussed. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Visualization of bubble dynamics in foam injection molding
Authors: Mahmoodi Mehdi , Behravesh Amir H. , Rezavand S. A. Mohammad , Pashaei Amir
Published: February 2010

This article presents a visualization study on nonisothermal bubble growth and collapse in the foam injection molding process (FIM). Observation study can give more insight to the bubble growth in foaming process, especially in the challenging injection foaming process. In this study, besides the growth of bubbles, collapse of the bubbles was also observed which could provide knowledge to the final foam morphology. Cell growth vs. time was recorded and analyzed using a software‐equipped high speed camera. To investigate the cell collapse, various holding pressure was exerted on the gas‐charged molten polymer. The amount of holding pressure had noticeable effect on the rate of bubble collapse. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Study of compatibility, morphology structure and mechanical properties of CPVC/ABS blends
Authors: Zhang Li‐Xin , Zhou Chao , Sun Shu‐Lin , Ren Liang , Ma Xiao‐Lin , Zhang Ming‐Yao , Zhang Hui‐Xuan
Published: February 2010

Compatibility, morphology structure, and mechanical properties of CPVC/ABS (Chlorinated polyvinyl chloride/acrylonitrile‐butadiene‐styrene) blends were studied. The core‐shell ratios of ABS were set at 40/60 and 70/30. The interface interactions between ABS and CPVC were changed by modifying the acrylonitrile (AN) content of the shell. The compatibility of CPVC with the shell of ABS was studied by the blends of CPVC/SAN with different AN content in SAN. Dynamic mechanical analysis results of CPVC/SAN were in accordance with the morphological properties of CPVC/ABS. The mechanical properties of CPVC/ABS blends in which the polybutadiene content was set to 15 wt % were studied. Results showed, with the change of AN content, the impact strength followed different way for CPVC/ABS blends with different core‐shell ratios of ABS because of the influence of the compatibility. When the core‐shell ratio was 40/60, the CPVC/ABS blends were much ductile in more widely AN range than the blends, whereas the core‐shell ratio of ABS was 70/30. The differences also showed in the SEM micrographs by the investigation of toughening mechanism. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Effect of 3‐aminopropyltriethoxysilane and N,N‐ dimethyldodecylamine as modifiers of Na+‐montmorillonite on SBR/organoclay nanocomposites
Authors: Kim Wook‐Soo , Yi Juhui , Lee Dong‐Hyun , Kim Il‐Jin , Son Woo‐Jung , Bae Jong‐Woo , Kim Wonho
Published: February 2010

In this study, styrene butadiene rubber (SBR)/organoclay nanocomposites were manufactured using the latex method with 3‐aminopropyltriethoxysilane (APTES) and N,N‐dimethyldodecylamine (DDA) as modifiers. The layer‐to‐layer distance of the silicates was observed according to each manufacturing process for APTES as the modifier using the X‐ray diffraction (XRD) method. From the XRD results and the TEM images, the dispersion of the silicates impoved for both APTES‐MMT and DDA‐MMT, and the dispersion of the silicates with the DDA modifier improved more than the APTES modifier. The SBR/DDA‐MMT compound exhibited the fastest scorch time, optimal vulcanization time, and cure rate. The dynamic viscoelastic properties of the SBR/APTES‐MMT compound were measured according to the change in the strain amplitude in order determine if a covalent bond was formed between APTES and bis(triethoxysilyl‐propyl)tetrasulfide (TESPT). The mechanical properties of the SBR/DDA‐MMT nanocomposite improved more than the SBR/APTES‐MMT composite because the vulcanization effects of alkylamine and the dispersion of silicates within the rubber matrix were relatively good. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and characterization of PEGylated terlipressin
Authors: Wang Xiufang , Tian Yong , Lin Hansen , Zang Linquan
Published: February 2010

Terlipressin was chemically modified by reaction with succinimidyl propionate‐ monomethoxy polyethylene glycol (mPEG‐SPA). To determine the PEGylated degree, the position and the optimized condition for PEGylated terlipressin, the reactions were monitored in different pH value buffers at different molar ratios by reversed‐phase high performance liquid chromatography (RP‐HPLC). Tryptic digestion and matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF MS) was used. The results showed that the amount of mono‐PEG‐terlipressin was higher at lower pH value and lower content of PEG. Meanwhile, the amount of di‐PEG‐terlipressin was higher at higher pH value and higher content of PEG under the conditions investigated. The position of PEGylated terlipressin was confirmed by tryptic digestion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Microstructural studies of PMMA impregnated mortars
Authors: Nair Priya , Ku Du Hyun , Lee Chul Woo , Park Hun Young , Song Ha Young , Lee Sang Su , Lee Won Mook
Published: February 2010

Studies on cement concrete microstructures are carried out to explain experimentally observed phenomenon and for modeling of concrete at the macroscopic level. In this article, the preparation of polymer impregnated mortar (PIC) is carried out by partially or fully replacing the pores in the cement mortars (OPC) by PMMA. The effect of this polymer impregnation on density and morphology of the cement matrix is studied. The microstructural changes in the mortar, on exposure of these specimens to hydrochloric acid and sea water for 7 and 28 days, are also investigated in this article. The above studies indicated that the polymer addition decreased the voids in the mortar thereby preventing leaching of water soluble salts present in the OPC. It was observed that the polymer also prevented the external chemical media from permeating into the cement matrix and undergoing interactions with it. It is concluded that the durability and chemical resistance properties of the PIC are better compared with OPC. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Toughening of recycled poly(ethylene terephthalate) with clay‐compatibilized rubber phase
Authors: Kelnar Ivan , Sukhanov Valentin , Rotrekl Jakub , Kaprálková Ludmila
Published: February 2010

Recycled bottle‐grade PET (rPET) is a valuable low‐cost polymeric material. However, enhancement of its mechanical properties is necessary for many applications. This work is focused on clay‐reinforced/compatibilized rPET/elastomer system. Although the clay addition to various rPET/elastomer blends caused a remarkable refinement of structure, more pronounced for clay with less polar modification, both a gain or decrease in strength and toughness occurred, whereas an increase in modulus was found for all systems. This is a consequence of simultaneous complex affecting many parameters by clay and both antagonistic and synergistic combination of respective effects. Best results were found for low contents of EPR rubber and its preblending with clay. The presented results indicate that a suitable combination of nanosilicates with rubber can lead to rPET materials with fairly enhanced properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Design and development of temperature sensitive porous poly(NIPAAm‐AMPS) hydrogels for drug release of doxorubicin‐a cancer chemotherapy drug
Authors: Varaprasad K. , Ravindra S. , Reddy N. Narayana , Vimala K. , Raju K. Mohana
Published: February 2010

Temperature sensitive polymer network porous hydrogels were developed with N‐Isopropylacrylamide (NIPAAm) and AMPS (2‐acrylamido‐2‐methyl‐1‐propanesulfonicacid), as well as with sucrose as porogen by crosslinking with hydrophilic crosslinker N,N1‐methylenebisacrylamide (MBA). The temperature responsive behaviour, the swelling/deswelling kinetics of the hydrogels were investigated. The structural and morphological characterizations of the developed hydrogels were obtained from FTIR spectroscopy and scanning electron microscopy (SEM). The increment in the lower critical solution temperature (LCST) of NIPAAm hydrogels can be done with the help of AMPS and it is confirmed with differential scanning calorimetry (DSC) as well as temperature dependent swelling curves. The model cancer chemotherapy drug Doxorubicin (Dox) was loaded into theses hydrogels and the release studies as well as the released profiles of the drug showed that more than 8–54% of the loaded drug was released in the first half‐an‐hour at a buffer solution of 7.4 and the rest of the drug was released slowly. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Bio‐hybrid nanocomposite coatings from sonicated chitosan and nanoclay
Authors: Vartiainen Jari , Tuominen Mikko , Nättinen Kalle
Published: February 2010

Nanocomposite films and coatings with improved properties were produced from ultrasonic dispersed chitosan and hydrophilic bentonite nanoclay. Bio‐hybrid coatings were applied onto argon–plasma‐activated LDPE coated paper. The intercalation of chitosan in the silicate layers was confirmed by the decrease of diffraction angles as the chitosan/nanoclay ratio increased. Nanocomposite films and multilayer coatings had improved barrier properties against oxygen, water vapor, grease, and UV‐light transmission. Oxygen transmission was significantly reduced under all humidity conditions. In dry conditions, over 99% reduction and at 80% relative humidity almost 75% reduction in oxygen transmission rates was obtained. Hydrophilic chitosan was lacking the capability of preventing water vapor transmission, thus total barrier effect of nanoclay containing films was not more than 15% as compared with pure chitosan. Because to very thin coatings (≤1 μm), nanoclay containing chitosan did not have antimicrobial activity against test strains. All coating raw materials were “generally recognized as safe” (GRAS) and the calculated total migration was in all cases ≤6 mg/dm2, thus the coatings met the requirements set by the packaging legislation. Processing of the developed bio‐hybrid nanocomposite coated materials was safe as the amounts of released particles under rubbing conditions were comparable with the particle concentrations in a normal office environment. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Biodegradable poly(ethylene succinate) blends and copolymers containing minor amounts of poly(butylene succinate)
Authors: Lu Hsin‐Ying , Chen Ming , Chen Chi He , Lu Jin‐Shan , Hoang Kim‐Chi , Tseng Min
Published: February 2010

Poly(ethylene succinate) (PES), poly(butylene succinate) (PBS), and PES‐rich copolyesters were synthesized using an effective catalyst, titanium tetraisopropoxide. PES was blended with minor amounts of PBS for the comparison. The compositions of the copolyesters and the blends were determined from NMR spectra. Their thermal properties were studied using a differential scanning calorimeter (DSC), a temperature modulated DSC (TMDSC), and a thermogravimetric analyzer. No significant difference exists among the thermal stabilities of these polyesters and blends. For the blends, the reversible curves of TMDSC showed a distinct glass‐rubber transition temperature (Tg), however, the variation of the Tg values with the blend compositions was small. Isothermal crystallization kinetics and the melting behavior after crystallization were examined using DSC. Wide‐angle X‐ray diffractograms (WAXD) were obtained for the isothermally crystallized specimens. The results of DSC and WAXD indicate that the blends have a higher degree of crystallinity and a higher melting temperature than those of the corresponding copolymers. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Glycan profiling of anti–citrullinated protein antibodies isolated from human serum and synovial fluid
Authors: Scherer Hans U. , van der Woude Diane , Ioan‐Facsinay Andreea , el Bannoudi Hanane , Trouw Leendert A. , Wang Jun , Häupl Thomas , Burmester Gerd‐R. , Deelder André M. , Huizinga Tom W. J. , Wuhrer Manfred , Toes René E. M.
Published: February 2010

Objective

Anti–citrullinated protein antibodies (ACPA) exhibit unique specificity for rheumatoid arthritis. However, it is incompletely understood whether and how ACPA contribute to disease pathogenesis. The Fc part of human IgG carries 2 N‐linked glycan moieties that are crucial for the structural stability of the antibody and that modulate both its binding affinity to Fcγ receptors and its ability to activate complement. We undertook this study to analyze Fc glycosylation of IgG1 ACPA in serum and synovial fluid (SF) in order to further characterize the immune response to citrullinated antigens.

Methods

ACPA were isolated by affinity purification using cyclic citrullinated peptides as antigen. IgG1 Fc glycosylation was analyzed by mass spectrometry. ACPA IgG1 glycan profiles were compared with glycan profiles of total serum IgG1 obtained from 85 well‐characterized patients. Glycan profiles of paired SF and serum samples were available from 11 additional patients.

Results

Compared with the pool of serum IgG1, ACPA IgG1 lacked terminal sialic acid residues. In SF, ACPA were highly agalactosylated and lacked sialic acid residues, a feature that was not detected for total SF IgG1. Moreover, differential ACPA glycan profiles were detected in rheumatoid factor (RF)–positive and RF‐negative patients.

Conclusion

ACPA IgG1 exhibit a specific Fc‐linked glycan profile that is distinct from that of total serum IgG1. Moreover, Fc glycosylation of ACPA differs markedly between SF and serum. Since Fc glycosylation directly affects the recruitment of Fc‐mediated effector mechanisms, these data could further our understanding of the contribution of ACPA to disease pathogenesis.
A comparison study of some Arabic root finding algorithms
Authors: Al‐Shawakfa Emad , Al‐Badarneh Amer , Shatnawi Safwan , Al‐Rabab'ah Khaleel , Bani‐Ismail Basel
Published: February 2010

Arabic has a complex structure, which makes it difficult to apply natural language processing (NLP). Much research on Arabic NLP (ANLP) does exist; however, it is not as mature as that of other languages. Finding Arabic roots is an important step toward conducting effective research on most of ANLP applications. The authors have studied and compared six root‐finding algorithms with success rates of over 90%. All algorithms of this study did not use the same testing corpus and/or benchmarking measures. They unified the testing process by implementing their own algorithm descriptions and building a corpus out of 3823 triliteral roots, applying 73 triliteral patterns, and with 18 affixes, producing around 27.6 million words. They tested the algorithms with the generated corpus and have obtained interesting results; they offer to share the corpus freely for benchmarking and ANLP research.
Redesigning of anti‐c‐Met single chain Fv antibody for the cytoplasmic folding and its structural analysis
Authors: Edwardraja Selvakumar , Neelamegam Rameshkumar , Ramadoss Vijayaraj , Venkatesan Subramanian , Lee Sun‐Gu
Published: February 2010

Typically, single chain Fv antibodies are unable to fold properly under a reducing cytoplasm because of the reduction of disulfide bonds. The inability to fold limits both the production of the functional scFvs and their targeting against antigens, which are generally executed in a reducing cytoplasm. In this study, the target scFv CDR was grafted with stable human consensus framework sequences, which enabled the generation of a foldable scFv in a reducing cytoplasm of Escherichia coli. Additionally, the structural features affecting the folding efficiency of the engineered scFv were identified by analyzing the predicted structure. An anti‐c‐Met scFv, which was a cytoplasmic non‐foldable protein, was redesigned as the model system. This study confirmed that the engineered anti‐c‐Met scFv was folded into its native form in the cytoplasm of E. coli BL21(DE3) without a significant loss in the specific binding activity against c‐Met antigen. The structures of the wild‐type anti‐c‐Met scFv and the engineered scFv were predicted using homology modeling. A comparative analysis based on the sequence and structure showed that the hydrophobicity of 12 solvent exposed residues decreased, and two newly formed salt bridges might have improved the folding efficiency of the engineered scFv under the reducing condition. Biotechnol. Bioeng. 2010; 106: 367–375. © 2010 Wiley Periodicals, Inc.
Factors promoting emissions of nitrous oxide and nitric oxide from denitrifying sequencing batch reactors operated with methanol and ethanol as electron donors
Authors: Lu Huijie , Chandran Kartik
Published: February 2010

The emissions of nitrous oxide (N2O) and nitric oxide (NO) from biological nitrogen removal (BNR) operations via nitrification and denitrification is gaining increased prominence. While many factors relevant to the operation of denitrifying reactors can influence N2O and NO emissions from them, the role of different organic carbon sources on these emissions has not been systematically addressed or interpreted. The overall goal of this study was to evaluate the impact of three factors, organic carbon limitation, nitrite concentrations, and dissolved oxygen concentrations on gaseous N2O and NO emissions from two sequencing batch reactors (SBRs), operated, respectively, with methanol and ethanol as electron donors. During undisturbed ultimate‐state operation, emissions of both N2O and NO from either reactor were minimal and in the range of <0.2% of influent nitrate‐N load. Subsequently, the two reactors were challenged with transient organic carbon limitation and nitrite pulses, both of which had little impact on N2O or NO emissions for either electron donor. In contrast, transient exposure to oxygen led to increased production of N2O (up to 7.1% of influent nitrate‐N load) from ethanol grown cultures, owing to their higher kinetics and potentially lower susceptibility to oxygen inhibition. A similar increase in N2O production was not observed from methanol grown cultures. These results suggest that for dissolved oxygen, but not for carbon limitation or nitrite exposure, N2O emission from heterotrophic denitrification reactors can vary as a function of the electron donor used. Biotechnol. Bioeng. 2010; 106: 390–398. © 2010 Wiley Periodicals, Inc.
An integrated electrical drive control laboratory: Speed control of induction motors
Authors: Dandil Bes̨ir
Published: February 2010

This paper presents an integrated environment for speed control of vector controlled induction motor (IM) including simulation and experimental study. In the prepared integrated environment, students and researchers can realise the speed control of IM by selecting the classical controllers such as proportional + integral + derivative (PID) and integral + proportional (IP) or intelligent controllers such as fuzzy (FC), neural network (NNC) and neuro‐fuzzy (NFC). Users can perform simulation and experimental studies on‐line to evaluate performance of the control system under parameter and load variations in IM drive. The integrated environment allows users to compare simulation and experimental results and evaluate basic distinctions between classical and intelligent controllers. Furthermore, performance of the controller designed by the user can be tested on‐line. Important variables of drive system can be monitored as graphically or saved as digitally for further processing by using the designed graphical user interface (GUI). © 2010 Wiley Periodicals, Inc. Comput Appl Eng Educ 20: 410–418, 2012
Towards Preparative Scale Steroid Hydroxylation with Cytochrome P450 Monooxygenase CYP106A2
Authors: Zehentgruber Daniela , Hannemann Frank , Bleif Sabrina , Bernhardt Rita , Lütz Stephan
Published: February 2010

Cytochrome P450 monooxygenases are of outstanding interest for the synthesis of pharmaceuticals and fine chemicals, due to their ability to hydroxylate CH bonds mainly in a stereo‐ and regioselective manner. CYP106A2 from Bacillus megaterium ATCC 13368, one of only a few known bacterial steroid hydroxylases, enables the oxidation of 3‐keto‐4‐ene steroids mainly at position 15. We expressed this enzyme together with the electron‐transfer partners bovine adrenodoxin and adrenodoxin reductase in Escherichia coli. Additionally an enzyme‐coupled cofactor regeneration system was implemented by expressing alcohol dehydrogenase from Lactobacillus brevis. By studying the conversion of progesterone and testosterone, the bottlenecks of these P450‐catalyzed hydroxylations were identified. Substrate transport into the cell and substrate solubility turned out to be crucial for the overall performance. Based on these investigations we developed a new concept for CYP106A2‐catalyzed steroid hydroxylations by which the productivity of progesterone and testosterone conversion could be increased up to 18‐fold to yield an absolute productivity up to 5.5 g L−1 d−1. Product extraction with absorber resins allowed the recovery of quantitative amounts of 15β‐OH‐progesterone and 15β‐OH‐testosterone and also the reuse of the biocatalyst.
Next‐Generation Catalysis for Renewables: Combining Enzymatic with Inorganic Heterogeneous Catalysis for Bulk Chemical Production
Authors: Vennestrøm Peter N. R. , Christensen Claus H. , Pedersen Sven , Grunwaldt Jan‐Dierk , Woodley John M.
Published: February 2010

Nowadays, production of bulk and commodity chemicals from renewable feedstocks is widely debated and investigated as an alternative to the fossil platform. The conversion of biomass necessitates the development of a new generation of catalysts that enable new kinds of reactions from a different chemical platform under different conditions than those conventionally employed. Indeed, new process and catalyst concepts need to be established. Both enzymatic catalysis (biocatalysis) and heterogeneous inorganic catalysis are likely to play a major role and, potentially, be combined. One type of combination involves one‐pot cascade catalysis with active sites from bio‐ and inorganic catalysts. In this article the emphasis is placed specifically on oxidase systems involving the coproduction of hydrogen peroxide, which can be used to create new in situ collaborative oxidation reactions for bulk chemical production.
The Richest Collection of Tautomeric Polymorphs: The Case of 2‐Thiobarbituric Acid
Authors: Chierotti Michele R. , Ferrero Luca , Garino Nadia , Gobetto Roberto , Pellegrino Luca , Braga Dario , Grepioni Fabrizia , Maini Lucia
Published: February 2010

Five new polymorphs and one hydrated form of 2‐thiobarbituric acid have been isolated and characterised by solid‐state methods. In both the crystalline form II and in the hydrate form, the 2‐thiobarbituric molecules are present in the enol form, whereas only the keto isomer is present in crystalline forms I (reported in 1967 by Calas and Martinex), III, V and VI. In form IV, on the other hand, a 50:50 ordered mixture of enol/keto molecules is present. All new forms have been characterised by single‐crystal X‐ray diffraction, 1D and 2D (1H, 13C, and 15N) solid‐state NMR spectroscopy, Raman spectroscopy and X‐ray powder diffraction at variable temperature. It has been possible to induce keto–enol conversion between the forms by mechanical methods. The role of hydrogen‐bond interactions in determining the relative stability of the polymorphs and as a driving force in the conversions has been ascertained. To the best of the authors’ knowledge, the 2‐thiobarbituric family of crystal forms represents the richest collection of examples of tautomeric polymorphism so far reported in the literature.
Einsatz des Strahlzonen‐Schlaufenreaktors bei stofftransportlimitierten, mehrphasigen chemischen Reaktionen
Authors: Wiedemann M. , John S. , Schlüter M. , Kutschera D. , Riener F.‐X. , Döring W. , Neumann S. , Eisenlauer J.
Published: February 2010

Viele chemische aber auch biochemische Reaktionen unterliegen Transportlimitierungen, die Umsatz und Ausbeute beschränken. So kommt insbesondere bei schnellen Reaktionen dem Transport durch Grenzschichten oder Phasengrenzflächen oder auch bei schleichenden Strömungen z. B. durch Biofilme der Überwindung von Transportlimitierungen eine herausragende Bedeutung zu. Durch hohe volumenspezifische Energieeinträge können spezifische Phasengrenzflächen vergrößert und die Mikrovermischung intensiviert werden, wofür zunehmend mikrostrukturierte Systeme oder strahlengetriebene Reaktoren zur Anwendung kommen. Ein Beispiel hierfür ist der Strahlzonen‐Schlaufenreaktor, der Transportprozesse auf unterschiedlichen Skalen gezielt nutzbar macht. In den letzten Jahren konnte der Strahlzonen‐Schlaufenreaktor erfolgreich auf verschiedene Prozesse der biologischen Abwasserreinigung und chemischen Reaktionsführung angewendet werden, wobei die Prinzipien der Aufhebung von Stofftransportlimitierungen sich als universell übertragbar erwiesen haben. In diesem Beitrag sollen exemplarisch einige Anwendungsbereiche des vor 15 Jahren von Prof. Räbiger entwickelten Strahlzonen‐Schlaufenreaktors vorgestellt und diskutiert werden.
Inhibition of Human DHODH by 4‐Hydroxycoumarins, Fenamic Acids, andN‐(Alkylcarbonyl)anthranilic Acids Identified by Structure‐Guided Fragment Selection
Authors: Fritzson Ingela , Svensson Bo , Al‐Karadaghi Salam , Walse Björn , Wellmar Ulf , Nilsson Ulf J. , da Graça Thrige Dorthe , Jönsson Stig
Published: February 2010

A strategy that combines virtual screening and structure‐guided selection of fragments was used to identify three unexplored classes of human DHODH inhibitor compounds: 4‐hydroxycoumarins, fenamic acids, andN‐(alkylcarbonyl)anthranilic acids. Structure‐guided selection of fragments targeting the inner subsite of the DHODH ubiquinone binding site made these findings possible with screening of fewer than 300 fragments in a DHODH assay. Fragments from the three inhibitor classes identified were subsequently chemically expanded to target an additional subsite of hydrophobic character. All three classes were found to exhibit distinct structure–activity relationships upon expansion. The novelN‐(alkylcarbonyl)anthranilic acid class shows the most promising potency against human DHODH, with IC50values in the low nanomolar range. The structure of human DHODH in complex with an inhibitor of this class is presented.
Peptide Architecture: Adding an α‐Helix to the PYY Lysine Side Chain Provides Nanomolar Binding and Body‐Weight‐Lowering Effects
Authors: Pedersen Søren L. , Sasikumar Pottayil G. , Vrang Niels , Jensen Knud J.
Published: February 2010

The gut hormone PYY3‐36 influences food intake and body weight via interaction with hypothalamic presynaptic Y2 receptors (Y2R). Novel Y2R‐selective analogues of PYY3‐36 are therefore potential drug candidates for the treatment of obesity. It has been hypothesized that PYY3‐36 and possibly also the related PP‐fold peptides, NPY and PP, bind to the membrane via their amphipathic α‐helix prior to receptor interaction. The PYY3‐36 amphipathic α‐helix causes the peptide to associate with the membrane, making it essential for Y receptor potency as it potentially guides the C‐terminal pentapeptide into the correct conformation for receptor activation. Based on this hypothesis, the importance of the amphipathic nature of PYY3‐36, as well as the ability of amphipathic α‐helices to interact in solution to form di‐ and tetramers, we redesigned the peptide architecture by addition of an amphipathic α‐helix via the Lys 4 side chain of PYY3‐36. Two different amphipathic sequences were introduced; first, PYY17‐31, the native α‐helix of PYY, and secondly, its retro counterpart, PYY31‐17, which is also predicted to form an α‐helix. Moreover, several different turn motifs between the branching point and the additional α‐helix were tested. Several novel peptides with nanomolar Y2R binding affinities, as well as increased Y receptor selectivity, were identified. CD experiments showed the modifications to be well accepted, and an increase in mean ellipticity (ME) signifying an increased degree of α‐helicity was observed. Receptor binding experiments indicated that the direction of the additional α‐helix is less important, in contrast to the turn motifs, which greatly affect the Y1R binding and thus determine the Y1R activity. Conversely, the structure–activity relationships from in vivo data showed that the peptide containing the retro‐sequence was inactive, even though the binding data demonstrated high affinity and selectivity. This demonstrates that radical redesign of peptide architecture can provide nanomolar binding with improved subtype selectivity and with in vivo efficacy.