bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simple and safe synthesis of microporous aluminophosphate molecular sieves by ionothermal approach
Authors: Han Lijun , Wang Yibo , Li Cuixia , Zhang Suojiang , Lu Xingmei , Cao Meijuan 
Published: November 2007

AbstractPure and transition metal (Co, Fe) containing aluminophosphate molecular sieves were synthesized ionothermally by using a series of imidazolium‐based ionic liquids as both solvent and structure‐directing agent. Adopting this novel method, a large number of volatile organic solvents can be avoided, and the synthesis can be operated at near atmospheric pressure. Thus, the preparation becomes simple and safe compared with hydrothermal and solvothermal method. And, the recycling of ionic liquid can make the industrial synthesis process more efficient and environmental. The powder XRD patterns and FT‐IR spectra displayed that all the synthesized samples were with sodalite structure. Crystal data for Co‐substituted analogue: cubic, Pm‐3n, a = 9.0192 Å, and magnetic property analysis showed weak antiferromagnetic interactions between Co ions. The influences of synthesis conditions such as P2O5/Al2O3 ratio, crystallization temperature, and the variety of ionic liquids on the character of the products were systematically investigated. In addition, the recycling of ionic liquid was studied based on the NMR and TGA. © 2007 American Institute of Chemical Engineers AIChE J, 2008
Miniemulsification in high‐pressure homogenizers
Authors: Manea Mihaela , Chemtob Abraham , Paulis María , de la Cal José C. , Barandiaran María J. , Asua José M. 
Published: November 2007

AbstractThe mechanisms involved in the formation of high solids content composite polymer–monomer waterborne miniemulsions in a high‐pressure homogenizer were investigated combining experimental results and a mathematical model for the process. It was found that the final droplet size was the result of two consecutive processes: droplet break‐up and coagulation. The final droplet size was determined by the mechanism giving the largest droplet size © 2007 American Institute of Chemical Engineers AIChE J, 2008
Upper extremity musculoskeletal symptoms and disorders among a cohort of women employed in poultry processing
Authors: Lipscomb Hester , Kucera Kristen , Epling Carol , Dement John 
Published: November 2007

AbstractBackgroundWe evaluated musculoskeletal problems among women employed in poultry processing in rural northeastern North Carolina. Poultry processing is the largest single employer of women in this economically depressed region with a black majority population.MethodsData were collected from a cohort of 291 women through interviews and physical exams conducted at 6‐month intervals over 3 years. An index of cumulative exposure, based on departmental rankings and work history, was the primary exposure variable. Other variables of interest included work organization factors, other medical conditions, depressive symptoms, children in the home, and hand intensive home activities. Poisson regression with generalized estimating equations was used to evaluate factors associated with occurrences of upper extremity symptoms and incidence of disorders at follow‐up.ResultsSymptoms making it difficult to maintain work speed or quality and depressive symptoms at baseline were associated with symptoms at follow‐up; age, being overweight, and job insecurity at baseline were associated with incident disorders. After considering these factors, the exposure response pattern was J‐shaped with risk decreasing in the second quartile of cumulative exposure and then going steadily up; the effect was stronger for disorders.ConclusionsThe pattern of risk is consistent with onset of early musculoskeletal problems among women new to the industry followed by a later increase with continued exposure. Among this highly exposed population, the effects of depressive symptoms and work organization factors were diminished when cumulative exposure was considered, illustrating the contextual nature of the complex relationships between physical work exposures and psychosocial factors. Am. J. Ind. Med. 51:24–36, 2008. © 2007 Wiley‐Liss, Inc.
Nonisothermal crystallization of polyamide 66/poly(phenylene sulfide) blends
Authors: Zhang Richao , Huang Yigang , Min Min , Gao Yong , Lu Ai , Lu Zhongyuan 
Published: November 2007

AbstractThe crystalline morphologies of isothermally and nonisothermally crystallized poly(phenylene sulfide) (PPS) and its blend with polyamide 66 (PA66) were investigated by polarized optical microscopy with a hot stage. The spherulite superstructure of PPS was greatly affected by crystallizable PA66; a Maltese cross was not clear, and the impingement between spherulites disappeared. This could be ascribed to the formation of small crystals of PA66, which filled in the PPS lamellae. The nonisothermal crystallization behavior was also measured by differential scanning calorimetry. The presence of PA66 changed the nonisothermal crystallization process of PPS. The maximum crystallization temperature of the PPS phase in the blend was higher that that of neat PPS, and this indicated that PA66 acted as a nucleus for PPS. Also, the compatibilizer poly(ethylene‐stat‐methacrylate) (EMA) was added to modify the interfacial interplay of the PA66/PPS blend system. The addition of EMA greatly influenced the nonisothermal crystallization process of the PPS phase in the blend system. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Hygrothermal ageing of an epoxy adhesive used in FRP strengthening of concrete
Authors: Yang Quan , Xian Guijun , Karbhari Vistasp M. 
Published: November 2007

AbstractThe efficiency of strengthening of deteriorating concrete through the external bonding of prefabricated fiber reinforced composite strips to the concrete substrate depends on the durability of the adhesive. In this application, adhesives can be exposed to water and salt water, as well as alkali solution resulting from the permeation of water through concrete. This paper presents the results of a durability program designed to study the effects of ageing and environment on the durability of a typical adhesive used in external bonding, through characterization of moisture uptake and cure and investigation by dynamic thermal mechanical analysis, thermogravimetric analysis, differential scanning calorimetry, and tensile testing. It is seen that the adhesive shows two‐stage diffusion with primary deterioration taking place in the first phase. Exposure to moisture is seen to cause plasticization and decreases in performance characteristics. The decrease in glass transition temperature due to hygrothermal ageing is such that the level is very close to the Federal Aviation Authority (FAA) recommended value of the wet glass transition temperature being at least 30°F higher than the maximum operation temperature. Overall, the effect of salt solution exposure is seen to have the least effect, whereas exposure to concrete based alkali solution has the greatest deteriorative effect. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Water remaining properties of nonwoven fabrics treated with the polyurethane polymers containing carboxylic acid group and the thermal and structural characterization of the polymers
Authors: Suen Maw‐Cherng , Lee Hsun‐Tsing , Chen Hung‐En , Chen Cheng‐Chi 
Published: November 2007

AbstractThree low‐molecular‐weight polyurethanes (LMWPU) containing various amounts of carboxylic acid were synthesized and applied on the nonwoven fabric for the improvement of water remaining property. The chemical structure of the LMWPUs was confirmed with 1H‐NMR and 13C‐NMR. The molecular weights of those three LMWPUs ranged from 3100 to 4200 g/mol. The results showed that the add‐on values were increased with the increasing of the content of 2,2‐bis(hydroxymethyl)propionic acid in LMWPU at a same resin concentration in padding bath. However, the water remaining values were decreased with the increasing of the content of 2,2‐bis(hydroxymethyl)propionic acid in LMWPU for a given add‐on value. The thermal properties, such as thermo‐degradation and the values of Tg and Tm of the polymers, could not affect the water remaining property of the treated fabrics. The analyses of X‐ray diffraction patterns and polarizing microscope observations showed that LMWPU with higher content of polytetramethyleneglycol had higher amorphous region. This phenomenon clearly supported that the values of water remaining were strongly affected by the amorphous region of the LMWPU polymers. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Molecular stability of chitosan in acid solutions stored at various conditions
Authors: Nguyen Thi Thanh Binh , Hein San , Ng Chuen‐How , Stevens Willem F. 
Published: November 2007

AbstractThe stability of chitosan with a degree of deacetylation (DD) of 88 and 81% was investigated in solution during storage for 60 days at various temperatures (60, 28, and 5°C) and acid concentrations (0.8M, 0.2M, and 0.1M). The first‐order rate constant of chain hydrolysis of 88%DD chitosan at 60°C was about 1.4 times higher than that of the 81%DD sample. At 28°C, the rates of hydrolysis for both chitosan samples were four to five times lower than those at 60°C and are similar. At 5°C, chain degradation was not significant. Although acetic acid caused significantly higher (P ≤ 0.05) chain scission than formic acid, no significant difference of rate change was observed among three different acid concentrations. Reprecipitation of dissolved chitosan was applied for its purification and to transfer dissolved chitosan to the solvent used to measure its molecular weight. Reprecipitation resulted in slightly lower molecular weight (P ≤ 0.05) for both 88%DD and 81%DD samples. The molecular weight of chitosan before and after reprecipitation had good linear relationship (r2 > 0.9). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Synthesis of a magnesium/aluminum/iron layered double hydroxide and its flammability characteristics in halogen‐free, flame‐retardant ethylene/vinyl acetate copolymer composites
Authors: Jiao Chuan‐Mei , Wang Zheng‐Zhou , Chen Xi‐Lei , Hu Yuan‐ 
Published: November 2007

AbstractMg–Al–Fe ternary hydrotalcites were synthesized by a coprecipitation method and characterized with powder X‐ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The flame‐retardant effects of Mg/Al–CO3 layered double hydroxides (LDHs) and Mg/Al/Fe–CO3 LDHs in an ethylene/vinyl acetate copolymer (EVA) were studied with the limited oxygen index (LOI), the UL‐94 test, and the cone calorimeter test (CCT), and the thermal degradation behavior of the composites was examined by thermogravimetric analysis. The results showed that the LOI values of the EVA/(Mg/Al/Fe–CO3 LDH) composites were basically higher than those of the EVA/(Mg/Al–CO3 LDH) composites at the same additive level. In the UL‐94 test, there was no rating for the EVA/(Mg/Al–CO3 LDH) composite at the 50% additive level, and a dripping phenomenon occurred. However, the EVA/(Mg/Al/Fe–CO3 LDH) composites at the same loading level of LDHs containing a suitable amount of Fe3+ ion reached the V‐0 rating, the dripping phenomenon disappearing. The CCTs indicated that the heat release rate (HRR) of the EVA composites with Mg/Al/Fe–CO3 LDHs containing a suitable amount of Fe3+ decreased greatly in comparison with that of the composites with Mg/Al–CO3 LDHs. The introduction of a given amount of Fe3+ ion into Mg/Al–CO3 LDHs resulted in an increase in the LOI, a decrease in the HRR, and the achievement of the UL‐94 V‐0 rating. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Copolymerization kinetics of poly(acrylonitrile‐ran‐2‐ethenyl‐pyridine) and its degradation apparent activation energy
Authors: Hou Chen , Qu Rongjun , Wang Chunhua , Ji Chunnuan , Sun Changmei , Ying Liang 
Published: November 2007

Abstract2‐Ethenyl‐pyridine (EPD) was first used to successfully copolymerize with acrylonitrile (AN) in a H2O/dimethyl formamide (DMF) mixture by using azobisisobutyronitrile as the initiator. Kinetics of copolymerization and degradation of poly(AN‐ran‐EPD) were discussed. The kinetic equation of copolymerization and the apparent activation energy of degradation of poly(AN‐ran‐EPD) were obtained. In H2O‐rich reaction medium, copolymerization followed the suspension polymerization more, but in DMF‐rich reaction medium, copolymerization followed the solution polymerization more. Increase in DMF concentration in the solvent mixture lead to a rapid increase in the degradation apparent activation energy. The apparent activation energy decreased quickly with an increase in EPD concentration, and such a change became less prominent as the molar ratio of EPD/AN went beyond 3/100. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Geographic information technologies, structuration theory, and the world trade center crisis
Authors: Harrison Teresa M. , Pardo Theresa , Gil–Garcia J. Ramon , Thompson Fiona , Juraga Dubravka 
Published: November 2007

AbstractAdvocates of geographic information technologies (GIT) have long claimed significant advantages to bringing a spatially oriented perspective to bear on organizational and policy decision making, however, for a variety of reasons, these advantages have been more difficult to realize in practice than might be supposed. In this article, we argue that awareness and appreciation of the potential value of GIT changed dramatically as a result of the World Trade Center (WTC) attacks on September 11, 2001. We use a structurationist theoretical perspective to show that GITs were “enacted” in a variety of novel ways by social actors thrust together by the demands of the crisis to form interorganizational systems, and we illustrate this process through three extended examples of GIT adaptation and innovation during the crisis. One lasting consequence of this episode is that GITs have moved from serving as a relatively static reference tool to a dynamic decision‐making tool for emergency situations. We conclude by suggesting that the crisis was a catalyst for change in the use of GIT and, reciprocally, in the social structures in which GIT will be deployed in the future.
You be the examiner!
Authors: Farley Peter C. , Magan Natisha , Charron Cynthia L. , Broomfield Nicholas I. , Farley A. Fay 
Published: November 2007

Abstract“You be the examiner!” is an online approach to providing students with immediate, readily accessible, and nonthreatening feedback on their understanding of key biochemical concepts. The feedback aims to affirm correct understanding and, where further study appears necessary, direct the student to the relevant sections of their textbook and/or lecturer‐provided study notes. Rather than providing model answers to previous examination questions, “You be the examiner” asks the students to evaluate typical “student” answers to such questions. Instead of a single “correct” answer, students encounter a range of answers that they must assess for accuracy and appropriateness.
Conjugation in Escherichia coli
Authors: Phornphisutthimas Somkiat , Thamchaipenet Arinthip , Panijpan Bhinyo 
Published: November 2007

AbstractBacterial conjugation is a genetic transfer that involves cell‐to‐cell between donor and recipient cells. With the current method used to teach students in genetic courses at the undergraduate level, the transconjugants are identified using bacterial physiology and/or antibiotic resistance. Using physiology, however, is difficult for both first‐year undergraduates and special science students at the high school levels, who do not have the basic knowledge. We have developed a laboratory exercise that comprises a simple and rapid technique for transferring bacterial DNA by conjugation and examining the transconjuants using only antibiotic resistance on agar. The identity of the right transconjuants is confirmed by agarose gel electrophoresis. This exercise is designed to help students understand how horizontal gene transfer occurs in bacteria by conjugation using Escherichia coli as a hands‐on learning model. Students should be able to draw concept maps of three DNA transfer methods on their own after carrying out the experiment and getting some additional information.
Teaching biochemistry at Lisbon University—Facing the challenge of the Bologna Declaration in the 25th anniversary of the biochemistry course
Authors: Farinha Carlos M. , Freire Ana Ponces 
Published: November 2007

AbstractThe biochemistry degree has been taught at Lisbon University for 25 years. Since its creation, the curriculum is characterized for being widely eclectic and multidisciplinary. The adoption of the concepts proposed in Europe by the Declaration of Bologna and incorporation of these ideas at Lisbon University is discussed here for the biochemistry degree.
Audio podcasting in a tablet PC‐enhanced biochemistry course
Authors: Lyles Heather , Robertson Brian , Mangino Michael , Cox James R. 
Published: November 2007

AbstractThis report describes the effects of making audio podcasts of all lectures in a large, basic biochemistry course promptly available to students. The audio podcasts complement a previously described approach in which a tablet PC is used to annotate PowerPoint slides with digital ink to produce electronic notes that can be archived. The fundamentals of this approach are described, and data from student attitudinal and informational surveys are presented. The survey data suggest that the students have a positive attitude toward the combination of tablet‐based instruction and audio podcasting. In addition, three students provide testimonials on how these technological tools allowed them to utilize their preferred learning styles to succeed in the course. Possible negative consequences of this approach, in terms of class attendance and note taking, are also analyzed and discussed.
Introducing DNA concepts to Swiss high school students based on a Brazilian educational game
Authors: da S. Cardona Tânia , Spiegel Carolina N. , Alves Gutemberg G. , Ducommun Jacques , Henriques‐Pons Andrea , Araújo‐Jorge Tania C. 
Published: November 2007

AbstractSubjects such as techniques for genetic diagnosis, cloning, sequencing, and gene therapy are now part of our lives and raise important questions about ethics, future medical diagnosis, and such. Students from different countries observe this explosion of biotechnological applications regardless of their social, academic, or cultural backgrounds, although they are not usually familiar with their theoretical genetic bases. To introduce some molecular biology concepts for high school students, we developed a new problem for the Brazilian board game “Discovering the cell” (“Célula Adentro©” in Portuguese), a pedagogic tool based on inquiry‐, cooperative‐, and problem‐based learning. This problem (Case) is based on the forensic DNA, which represents an interesting theme for students, as it recurrently appears on newspapers and television series. In this work, we tested this game with secondary students and teachers from Switzerland. Our results indicate that the game “Discovering the cell” is well accepted by both students and teachers and may represent a good pedagogical approach to help teaching complex themes in molecular biology, even with students from different socioeconomical, cultural, and academic backgrounds.
The discovery of biological enantioselectivity: Louis Pasteur and the fermentation of tartaric acid, 1857—A review and analysis 150 yr later
Authors: Gal Joseph 
Published: November 2007

AbstractNearly a decade after discovering molecular chirality in 1848, Louis Pasteur changed research direction and began investigating fermentations. Conflicting explanations have been given for this switch to microbiology, but the evidence strongly suggests that Pasteur's appointment in 1854 to the University of Lille—an agricultural‐industrial region where fermentation‐based manufacturing was of great importance—and an appeal for help in 1856 by a local manufacturer experiencing problems in his beetroot‐fermentation‐based alcohol production played a significant role. Thus began, in late 1856, Pasteur's pioneering studies of lactic and alcoholic fermentations. In 1857, reportedly as a result of a laboratory mishap, he found that in incubations of ammonium (±)‐tartrate with unidentified microorganisms (+)‐tartaric acid was consumed with considerable preference over (−)‐tartaric acid. In 1860, he demonstrated a similar enantioselectivity in the metabolism of tartaric acid by Penicillium glaucum, a common mold. Chance likely played a significant role both in Pasteur's shift to microbiology and his discovery of enantioselective tartrate fermentations, but he rejected pure serendipity as a significant factor in experimental science and in his own career. Pasteur's milestone discovery of biological enantioselectivity began the process that in the long run established the fundamental importance of molecular chirality in biology. biology. Chirality, 2007. © 2007 Wiley‐Liss, Inc.
Novel Properties of Photochromic Spirooxazine Nanoparticles
Authors: LIU Yuan‐Yuan , FAN Mei‐Gong , ZHANG Chang‐Rui , SHENG Xiao‐Hai , YAO Jian‐Nian 
Published: November 2007

AbstractThe nanoparticles of a spirooxazine (SPO) and its photomerocyanine (PMC) were prepared through the reprecipitation method. Two distinct features were observed. One is that the decaying lifetime for PMC nanoparticles was 600 times of that for the dispersed molecules, and the other is that the fluorescence intensity of SPO nanoparticles was enhanced by 240 times of that of the dispersed monomer.
Role of Mononuclear Rare Earth Metal Complexes in Promoting the Hydrolysis of 2‐Hydroxypropyl p‐Nitrophenyl Phosphate
Authors: WANG Rui , LIN Hai , LIN Hua‐Kuan 
Published: November 2007

AbstractTwo long‐chain multidentate ligands: 2,9‐di‐(n‐2′,5′,8′‐triazanonyl)‐1,10‐phenanthroline (L1) and 2,9‐di‐ (n‐4′,7′,10′‐triazaundecyl)‐1,10‐phenanthroline (L2) were synthesized. The hydrolytic kinetics of 2‐hydroxypropyl p‐nitrophenyl phosphate (HPNP) catalyzed by the complexes of L1 or L2 with La(III) or Gd(III) have been studied in aqueous solution at (298.2±0.1) K, I=0.10 mol·dm−3 KNO3 in pH 7.5–9.1, respectively, finding that the catalytic effect of GdL1 was the best among the four complexes for hydrolysis of HPNP. Its kLnLH−1, kLnL and pKa are 0.047 mol−1·L·s−1, 0.000074 mol−1·L·s−1 and 8.90, respectively. This paper expounded the studied result with the structure of the ligands and the properties of the metal ions, and deduced the catalysis mechanism.
An Ionic Liquid Bulk‐Modified Carbon Paste Electrode and Its Electrocatalytic Activity toward p‐Aminophenol
Authors: ZHANG Ya , ZHENG Jian‐Bin 
Published: November 2007

AbstractAn ionic liquid bulk‐modified carbon paste electrode (M‐CPE) has been fabricated by using 1‐heptyl‐3‐methylimidazolium bromide as a modifier. Cyclic voltammetry (CV) and differential pulse voltammetry (DPV) were used to evaluate the electrocatalytic activity of the proposed electrode by choosing p‐aminophenol (p‐AP) as a model compound. Both at a bare carbon paste electrode (CPE) and the M‐CPE, p‐AP yielded a pair of redox peaks in 0.1 mol·L−1 phosphate buffer solution (PBS, pH 7.0). At the CPE, the peak‐to‐peak potential separation (ΔEp) was 0.233 V, while at the M‐CPE the ΔEp was decreased to 0.105 V. Furthermore, the current response to p‐AP at the M‐CPE was 10.2 times of that at the CPE by DPV. The electron transfer rate constant (ks) of p‐AP at the M‐CPE was 13.3 times of that at the CPE. Under the optimal condition, a linear dependence of the catalytic current versus p‐AP concentration was obtained in the range of 2.0×10−6 to 3.0×10−4 mol·L−1 with a detection limit of 6.0×10−7 mol·L−1 by DPV. In addition, compared to other modified method the proposed electrode exhibited distinct advantages of simple prapartion, surface renewal, good reproducibility and good stability. It has been used to determine p‐AP in simulated wastewater samples.