bluuebunny/crossref_metadata_2025 huggingface dataset:
Poly(diphenylacetylene)s with Electron‐Donating Alkoxy and Electron‐Withdrawing Fluoroalkyl Groups: Effect of the Substituent on Fluorescence
Authors: Kwak Giseop , Wang Hong‐Qing , Choi Kyu‐Han , Song Kyu‐Ho , Kim Soon‐Hak , Kim Hyeok‐Soo , Lee Sam‐Jong , Cho Ho‐Young , Yu Eon‐Ju , Lee Hyo‐Jeong , Park Eun‐Jung , Park Lee‐Soon
Published: June 2007

New poly(diphenylacetylene)s with alkoxy and fluoroalkyl groups as electron‐donating and electron‐withdrawing groups, respectively, were synthesized by using a WCl6‐n‐Ph4Sn catalyst. The polymer solutions emitted strong, bluish‐green lights when photo‐excited. The polymers that contained the electron‐donating alkoxy groups showed longer fluorescence‐maximum peaks when compared to the polymers that contained the electron‐withdrawing fluoroalkyl groups. However, such an effect of the substituent on the absorption property was not clearly seen. The emission bands of the solid films did not show any significant red shift, relative to that of the dilute solution.

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RAG2 gene knockout in mice causes fatigue
Authors: Golumbek Paul T. , Keeling Richard M. , Connolly Anne M.
Published: June 2007

The effect of a disrupted immune system on the neuromuscular system is poorly characterized. We compared the strength and fatigue of RAG2−/− mice, which lack T‐cells and B‐cells, with immune intact controls. RAG2−/− mice demonstrated fatigue with shorter inverted hang‐times (HT) and voluntary wheel‐running (VWR) distance and total run times; they increased body weight more slowly but had proportionally normal forelimb grip strength (FGS) and VWR speed. Medial rectus femoris histopathology showed no change in fiber type proportions, no variation in type 2b fiber diameter, and no change in the percentage of central nuclei. There was no change in serum creatine kinase (CK) levels. Thus, in RAG2−/− mice body weight and fatigue were directly affected by a hypoactive immune system. Whether these effects were centrally or peripherally mediated is unknown. This model may help to explain fatigue in human conditions in which the immune system is suppressed or absent. Muscle Nerve, 2007
To profit or not to profit: Women entrepreneurs in India
Authors: Handy Femida , Ranade Bhagyashree , Kassam Meenaz
Published: June 2007

Entrepreneurial activity attracts certain kinds of individuals, whether it is to promote a social cause in the nonprofit sector or profit in the for‐profit sector. This article looks at the behavior of women entrepreneurs in India in both the for‐profit and nonprofit sectors to test for potential differences and similarities. We chose two groups of entrepreneurial women who founded and led relatively similar‐size organizations in the same city and who provided services primarily to women and children. Our findings show that while all nonprofit entrepreneurs receive a high payoff from promoting social causes, there is no single unifying payoff for for‐profit entrepreneurs. Family background and support, however, play an important role for both sets of entrepreneurs. We find that experience in the sector, social class, caste, and education in?uence entrepreneurial behavior and that this in?uence differs by sector.
Managing the donation service experience
Authors: Polonsky Michael Jay , Sargeant Adrian
Published: June 2007

This article examines the implications for nonprofits of managing donation exchanges using customer relationship management and service blueprinting. It presents a case study of one U.K.‐based nonprofit and identifies a range of issues that might make managing donation service exchanges more complex than occurs in the for‐profit setting. In particular, the fact that there are multiple simultaneous exchanges means that it may be difficult to separate donation processes from other organizational activities such as membership and campaigning. We explore the utility of service blueprinting in aiding the management of this complexity.
A novel approach to synthesis of functional CPVC and CPE or graft copolymers—in situchlorinating graft
Authors: Zhao Jiruo , Li Junyuan , Feng Ying , Yin Jinghua
Published: June 2007

A new process of graft copolymerization of poly(vinyl chloride) (PVC) and polyethylene (PE) with other monomers was developed. The grafted chlorinated poly(vinyl chloride) (CPVC) and chlorinated polyethylene (CPE) were synthesized byin situchlorinating graft copolymerization (ISCGC) and were characterized. Convincing evidence for grafting and the structure of graft copolymers was obtained using FT‐IR,1H‐NMR, gel permeation chromatography (GPC), and the vulcanized curves. Their mechanical properties were also measured. The results show that the products have different molecular structure from those prepared by other conventional graft processes. Their graft chains are short, being highly branched and chlorinated. The graft copolymers have no crosslinking structure. The unique molecular structure will make the materials equipped with special properties. Copyright © 2007 John Wiley & Sons, Ltd.
A new method for preparation of poly‐lauryl acrylate nanoparticles from nanoemulsions obtained by the phase inversion temperature process
Authors: Spernath Liat , Magdassi Shlomo
Published: June 2007

We describe a new method for the preparation of organic nanoparticles from nanoemulsions which were prepared by the phase inversion temperature (PIT) method. This is a low‐energy technique which does not require any special equipment such as high pressure homogenizers. In this work, the method is demonstrated for preparation of nanoparticles of poly‐lauryl acrylate containing, in some cases, a crosslinker (trimethylolpropane triacrylate—TMPTA) and pyrene as microviscosity and micropolarity probes, respectively. The nanoemulsions were prepared by using a poly(oxyethylene) nonionic surfactant, Brij 96V (POE (10) oleyl alcohol), and combinations of Brij 96V and Brij 92V (POE (2) oleyl alcohol), with acrylate monomers which form the oil phase in the oil‐in‐water (O/W) emulsions. The nanodroplets were polymerized, yielding nanoparticles having an average diameter between 50 and 120 nm with a narrow size distribution, using a water‐soluble thermal initiator (ammonium persulfate) and activated by ferrous ions, Fe+2. The emission colors of the pyrene‐embedded nanoemulsions changed from blue to violet after polymerization, due to the absence of excimers. This method may be applied for the preparation of a variety of polymeric nanoparticles, in which functional molecules are embedded within the particles. Copyright © 2007 John Wiley & Sons, Ltd.
Effect of synthesis method and buffer composition on the LCST of a smart copolymer of N‐isopropylacrylamide and acrylic acid
Authors: Minoo‐Rabeeh–Hobabi  , Hassanzadeh Davooud , Azarmi Shirzad , Entezami A. A.
Published: June 2007

Responsive polymers have been the focus of many studies during the past decade because of their ability to change according to environmental stimuli. In this paper, we report on the development of a method to synthesize a pH/temperature‐sensitive linear copolymer, poly(N‐isopropylacrylamide‐ co‐acrylic acid)(poly(NIPAAm‐co‐AAc)), with a molecular weight of about 106–105 Da in water using azobisisobutyronitrile (AIBN) as the initiator. The effects of the following on the lower critical solution temperature (LCST) of the copolymer and homopolymer of NIPAAm were investigated: the type of buffer salts and pH changes of test solutions, molecular weight and concentration of homopolymer/copolymer solutions, and AAc monomer molar feed ratio (mol%). The effects of different synthesis methods on the molecular weight and on the AAc content were also evaluated. The mechanism of action in environments with different pH values is discussed. Copyright © 2007 John Wiley & Sons, Ltd.
Identification of a novel p53 in‐frame deletion in a Li–Fraumeni‐like family
Authors: Schiffman Joshua D. , Chun Nicolette , Fisher Paul G. , Dahl Gary V. , Ford James M. , Eggerding Faye A.
Published: June 2007

We describe a 2‐year‐old female with a completely resected cerebral pilocytic astrocytoma who subsequently developed B‐progenitor acute lymphoblastic leukemia (ALL). Her father and paternal uncle were previously diagnosed with glioblastoma multiforme. Sequence analysis of the patient's p53 gene revealed a novel germline three base‐pair deletion (339_341delCTT) in exon 4, resulting in removal of an evolutionarily conserved phenylalanine amino acid residue at codon 113. The same mutation was found in the patient's two clinically unaffected siblings. The in‐frame deletion we describe has not previously been reported and adds to our understanding of the biologic effects of p53 gene mutation in Li–Fraumeni syndrome (LFS). Pediatr Blood Cancer 2008;50:914–916. © 2007 Wiley‐Liss, Inc.
Impairments in antifolate transport are common in retinoblastoma tumor samples
Authors: Gorlick Richard G. , Abramson David H. , Sowers Rebecca , Mazza Beth Anne , Dunkel Ira J.
Published: June 2007

Background

Many patients with retinoblastoma have a genetic predisposition to cancer and external beam radiation therapy and alkylating agent chemotherapy may increase their risk of secondary malignancy. Identification of effective chemotherapy agents for retinoblastoma that are not associated with an elevated risk of secondary malignancy would be beneficial.

Procedure

Twenty‐six specimens of fresh retinoblastoma tumor cells were studied in vitro with a PT430 competitive displacement assay. Differential displacement of the PT430 by methotrexate and not trimetrexate was considered indicative of a defect in reduced folate carrier (RFC)‐mediated transport. Elevations in the accumulation of PT430 were considered indicative of dihydrofolate reductase (DHFR) amplification.

Results

In 9 of the 26 (35%) samples, displacement by methotrexate was less than half the displacement by trimetrexate indicative of a defect in the RFC. In 5 of the 26 (19%) samples, trimetrexate did not displace the PT430. In 7 of 26 (27%) samples, the peak PT430 accumulation was suggestive of DHFR overexpression. Overall 9 of 26 (35%) samples had no evidence of a transport defect or DHFR overexpression and would be anticipated to be potentially sensitive to methotrexate. In 15 of the 26 (58%), no defects existed in trimetrexate displacement or DHFR overexpression and would be anticipated to be potentially sensitive to trimetrexate.

Conclusion

These results would support consideration of a phase II study to determine the effectiveness of trimetrexate for recurrent intra‐ocular retinoblastoma. Pediatr Blood Cancer 2008;50:573–576. © 2007 Wiley‐Liss, Inc.
Improvement in the outcome of children with germ cell tumors
Authors: Lopes Luiz Fernando , Sonaglio Viviane , Ribeiro Karina C.B. , Schneider Dominik T. , de Camargo Beatriz
Published: June 2007

Purpose

To describe the clinical characteristics and estimate the survival of children and adolescents with germ cell tumors treated with cisplatin‐based combination chemotherapy according to three different protocols in Brazil.

Methods

From 1983 to 1997, 106 patients were treated at the Hospital do Cancer, Sao Paulo for a diagnosis of germ cell tumor. We performed a retrospective review of the clinical and histopathological data to identify prognostic factors and evaluate their outcome.

Results

Patients were treated with only surgery (n = 32), surgery and radiotherapy (n = 1) and chemotherapy (n = 73). From 1983 to 1986 (period I), there were 30 patients and 21 received chemotherapy according to the modified VAB‐6 protocol. Twenty‐two of 35 patients registered between 1987 and 1991 (period II) were treated with EPO/VAC combination chemotherapy. From 1991 to 1997 (period III), there were 41 patients and 31 received chemotherapy according to the Brazilian TCG‐91 protocol. Important prognostic factors included stage (P < 0.001), metastatic status (P < 0.001) and surgical procedure at diagnosis (P < 0.001). An incremental improvement in outcomes was noted across the periods of treatment (P = 0.070). Five‐year OS was respectively 42.9 ± 10.8%, 53.9 ± 11.4% and 80.6 ± 7.1% for periods I, II, and III for the patients who received chemotherapy.

Conclusion

An improvement in the survival of children with germ cell tumors was achieved in the most recent trial (TCG‐91) with a risk adapted approach incorporating only cisplatin and etoposide. These results indicate that in selected patients complex three‐agent regimens may not be necessary to achieve long term survival. Pediatr Blood Cancer 2008;50:250–253. © 2007 Wiley‐Liss, Inc.
Serum ferritin underestimates liver iron concentration in transfusion independent thalassemia patients as compared to regularly transfused thalassemia and sickle cell patients
Authors: Pakbaz Zahra , Fischer Roland , Fung Ellen , Nielsen Peter , Harmatz Paul , Vichinsky Elliott
Published: June 2007

Serum ferritin (SF) and liver iron concentration (LIC), as measured by SQUID biosusceptometry, were assessed in a convenience sample of transfusion independent thalassemia patients (nTx‐Thal, n = 26), regularly transfused thalassemia (Tx‐Thal, n = 89), or sickle cell patients (SCD, n = 45) to investigate the severity of iron overload and the relationship between SF and LIC in nTx‐Thal compared to SCD and Tx‐Thal. SF correlated with LIC (RS = 0.53, P < 0.001), but was found to be a poor predictor for LIC. SF was significantly lower (P < 0.001) in nTx‐Thal patients than in other groups, despite similar LIC values. The SF‐to‐LIC ratio was significantly lower in nTx‐Thal compared to Tx‐Thal and SCD patients (median of 0.32, 0.87, and 1.2, respectively: P < 0.001). Due to underestimation of LIC by ferritin levels, chelation treatment may be delayed or misdirected in patients with thalassemia intermedia. Pediatr Blood Cancer 2007;49:329–332. © 2007 Wiley‐Liss, Inc.
Loss of antibody titers and effectiveness of revaccination in post‐chemotherapy pediatric sarcoma patients
Authors: Yu Jennifer , Chou Alexander J. , Lennox Alison , Kleiman Phillip , Wexler Leonard H. , Meyers Paul A. , Gorlick Richard
Published: June 2007

Background

Little is known about the effects of chemotherapy on patient antibody titers to vaccine‐preventable infectious diseases; thus, there is no standard protocol for revaccinating post‐chemotherapy patients.

Procedures

To assess losses of detectable antibody titers due to chemotherapy, we retrospectively examined antibody titers for tetanus, varicella, measles, mumps, rubella, hepatitis B, and polio in 109 pediatric sarcoma patients. We also evaluated revaccination data to determine current practices and efficacy of revaccination. We limited our sample to osteosarcoma, Ewing sarcoma, and rhabdomyosarcoma patients to control for the chemotherapy regimen patients received.

Results

Patients had pre‐treatment detectable antibody titer that fell within the range of healthy children's antibody titers. However, 71% of patients had post‐chemotherapy negative titers for at least one infectious disease. Patients most commonly had negative titers for hepatitis B (64%). Few patients had negative titers for measles (14%), mumps (9%), rubella (4%), polio 1 (0%), polio 2 (2.9%), polio 3 (4.8%), tetanus (5%), or varicella (11%). Revaccinations most frequently administered were hepatitis B and polio.

Conclusions

Our findings suggest that post‐chemotherapy patients may need to be revaccinated against certain vaccine‐preventable diseases including hepatitis B, tetanus, varicella, polio, measles, mumps, and rubella. Larger studies need to be performed to establish guidelines for revaccinating post‐chemotherapy pediatric patients. Pediatr Blood Cancer 2007;49:656–660. © 2007 Wiley‐Liss, Inc.
Polyester oligodiols by cationic AM copolymerization of L,L‐lactide and ε‐caprolactone initiated by diols
Authors: Baśko Małgorzata , Kubisa Przemyslaw
Published: June 2007

Cationic copolymerization of L,L‐lactide (LA) and ε‐caprolactone (CL) initiated by low molecular weight diols in the presence of acid catalyst gives corresponding copolyesters terminated at both ends with hydroxyl groups in practically quantitative yield. Copolymerization proceeds by Activated Monomer mechanism. LA is consumed preferentially and at the later stages of copolymerization the reaction mixture is enriched with CL. In spite of that, random distribution of both units is observed and end‐groups are mainly LA‐OH groups and not CL‐OH groups. This is explained by the fact that to reach high conversion of both comonomers the relatively long reaction times are required and at those conditions transesterification reaction becomes significant. Thus the microstructure of copolymers and the nature of the end‐groups is governed by transesterification rather then by the kinetics of comonomers incorporation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3090–3097, 2007
RGD peptide grafted biodegradable amphiphilic triblock copolymer poly(glutamic acid)‐b‐poly(L‐lactide)‐b‐poly(glutamic acid): Synthesis and self‐assembly
Authors: Deng Chao , Chen Xuesi , Sun Jing , Lu Tiancheng , Wang Wenshou , Jing Xiabin
Published: June 2007

A novel amphiphilic biodegradable triblock copolymer (PGL‐PLA‐PGL) with polylactide (PLA) as hydrophobic middle block and poly(glutamic acid) (PGL) as hydrophilic lateral blocks was successfully synthesized by ring‐opening polymerization (ROP) of L‐lactide (LA) and N‐carboxy anhydride (NCA) consecutively and by subsequent catalytic hydrogenation. The results of cell experiment of PGL‐PLA‐PGL suggested that PGL could improve biocompatibility of polyester obviously. The copolymer could form micelles of spindly shape easily in aqueous solution. The pendant carboxyl groups of the triblock copolymer were further activated with N‐hydroxysuccinimide and combined with a cell‐adhesive peptide GRGDSY. Incorporation of the oligopeptide further enhanced the hydrophilicity and led to formation of spherical micelles. PGL‐PLA‐PGL showed better cell adhesion and spreading ability than pure PLA and the GRGDSY‐containing copolymer exhibited even further improvement in cell adhesion and spreading ability, indicating that the copolymer could find a promising application in drug delivery or tissue engineering. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 3218–3230, 2007
Integrated mechanism for the morphological structure development in HDPE melt‐blown and machine‐direction‐oriented films
Authors: Bafna Ayush , McFaddin Douglas , Beaucage Gregory , Merrick‐Mack Jean , Mirabella Francis M.
Published: June 2007

The morphologies of a series of blown films and machine‐direction‐oriented (MDO) films, all produced from high density polyethylene, were characterized. In the blown film process, the crystalline morphology develops while the melt is under extensional stress. In the MDO process, drawing takes place in the solid state and deforms the crystalline morphology of the starting film. The films were characterized by wide‐angle X‐ray scattering (WAXS), small‐angle X‐ray scattering (SAXS) and atomic force microscopy to determine the lamellar morphology. The effect of the type of deformation on the lamellar morphology was studied and relationships were developed between the lamellar and polymer chain morphology using SAXS and WAXS. Blown and MDO films were found to have very different morphologies. However, an integrated mechanism was developed linking the sequential events in the deformation and morphology development in blown and MDO films. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1834–1844, 2007
Subacute proteome changes following traumatic injury of the developing brain: Implications for a dysregulation of neuronal migration and neurite arborization
Authors: Kaindl Angela M. , Zabel Claus , Stefovska Vanya , Lehnert Ron , Sifringer Marco , Klose Joachim , Ikonomidou Chrysanthy
Published: June 2007

Traumatic brain injury (TBI) is a major cause of morbidity and mortality among children and adolescents. To gain insight into developmental events influenced by TBI, we analyzed subacute mouse brain proteome changes in a percussion head trauma model at P7 ipsi‐ and contralateral to the site of injury. The comparison of brain proteomes of trauma mice and controls revealed reproducible changes in the intensity of 28 proteins (30 protein spots) in response to trauma. The changes detected suggest that TBI leads to apoptosis, inflammation, and oxidative stress. These changes were consistent with our results of histological and biochemical evaluation of the brains which revealed widespread apoptotic neurodegeneration, microglia activation, and increased levels of protein carbonyls. Furthermore, we detected changes in proteins involved in neuronal migration as well as axonal and dendritic growth and guidance, suggesting interference of trauma with these developmental events.
Crystal structure of calcium binding protein‐1 from Entamoeba histolytica: A novel arrangement of EF hand motifs
Authors: Kumar Shivesh , Padhan Narendra , Alam Neelima , Gourinath S.
Published: June 2007

Calcium plays a pivotal role in the pathogenesis of amoebiasis, a major disease caused by Entamoeba histolytica. Several EF‐hand containing calcium‐binding proteins (CaBPs) have been identified from E. histolytica. Even though these proteins have very high sequence similarity, they bind to different target proteins in a Ca2+ dependent manner, leading to different functional pathways (Yadava et al., Mol Biochem Parasito 1997;84:69–82; Chakrabarty et al., J Biol Chem 2004;279:12898–12908) The crystal structure of the Entamoeba histolytica calcium binding protein‐1 (EhCaBP1) has been determined at 2.4 Å resolution. The crystals were grown using MPD as precipitant and they belong to P63 space group with unit cell parameters of a = 95.25 Å, b = 95.25 Å, c = 64.99 Å. Only two out of the four expected EF hand motifs could be modeled into the electron density map and the final model refined to R factor of 25.6% and Free_R of 28%. Unlike CaM, the first two EF hand motifs in EhCaBP1 are connected by a long helix and form a dumbbell shaped structure. Owing to domain swapping oligomerization three EhCaBP1 molecules interact in a head to tail manner to form a triangular trimer. This arrangement allows the EF‐hand motif of one molecule to interact with that of an adjacent molecule to form a two EF‐hand domain similar to that seen in the N‐terminal domain of the NMR structure of CaBP1, calmodulin and troponin C. The oligomeric state of EhCaBP1 results in reduced flexibility between domains and may be responsible for the more limited set of targets recognized by EhCaBP1. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Tilted properties of the 67–78 fragment of α‐synuclein are responsible for membrane destabilization and neurotoxicity
Authors: Crowet Jean‐Marc , Lins Laurence , Dupiereux Ingrid , Elmoualija Benaïssa , Lorin Aurélien , Charloteaux Benoit , Stroobant Vincent , Heinen Ernst , Brasseur Robert
Published: June 2007

α‐Synuclein is a 140 residue protein associated with Parkinson's disease. Intraneural inclusions called Lewy bodies and Lewy neurites are mainly composed of α‐synuclein aggregated into amyloid fibrils. Other amyloidogenic proteins, such as the β amyloid peptide involved in Alzheimer's disease and the prion protein (PrP) associated with Creuztfeldt‐Jakob's disease, are known to possess “tilted peptides”. These peptides are short protein fragments that adopt an oblique orientation at a hydrophobic/hydrophilic interface, which enables destabilization of the membranes. In this paper, sequence analysis and molecular modelling predict that the 67–78 fragment of α‐synuclein is a tilted peptide. Its destabilizing properties were tested experimentally. The α‐synuclein 67–78 peptide is able to induce lipid mixing and leakage of unilamellar liposomes. The neuronal toxicity, studied using human neuroblastoma cells, demonstrated that the α‐synuclein 67–78 peptide induces neurotoxicity. A mutant designed by molecular modelling to be amphipathic was shown to be significantly less fusogenic and toxic than the wild type. In conclusion, we have identified a tilted peptide in α‐synuclein, which could be involved in the toxicity induced during amyloidogenesis of α‐synuclein. Proteins 2007. © 2007 Wiley‐Liss, Inc.
Synthesis and mass spectrometry of benzoxazoline, dimethyloxazoline and 4‐phenyloxazoline derivatives of polyunsaturated fatty acids
Authors: Kangani Cyrous O. , Kelley David E. , Evans Rhobert W.
Published: June 2007

Cyclic nitrogen moieties have proved to be of great value for the mass spectrometric location of double bonds in polyunsaturated fatty acids. However, their synthesis has traditionally required long reaction times and/or high temperatures. Recently, we introduced a one‐pot, high‐yield, mild and efficient method for the synthesis of various fatty acid amide derivatives. We have now extended this procedure to include the synthesis of benzoxazoline, dimethyloxazoline and 4‐phenyloxazoline analogs of a series of fatty acids containing 18 to 22 carbon atoms and 0 to 6 double bonds. A comparison of the mass spectral properties of the three derivatives of these saturated and unsaturated fatty acids is described. Copyright © 2007 John Wiley & Sons, Ltd.
Feedback control with signal transmission after‐effects
Authors: Gao Huijun , Lam James , Chen Tongwen , Wang Changhong
Published: June 2007

In many practical systems, the physical plant, controller, sensor, and actuator are difficult to be located at the same place, and thus signals are required to be transmitted from one place to another. One immediate problem arising from such situations is that signals may exhibit after‐effect phenomena during their transmission. In this paper, we present a new model to characterize the state‐feedback control systems with signal transmission after‐effects, which deals with the transmission after‐effects from sensor to controller and from controller to actuator separately. Analysis and synthesis results based on this new model are established by using a Lyapunov–Krasovskii approach. Numerical simulations are provided to illustrate the usefulness of the theoretical results. Copyright © 2007 John Wiley & Sons, Ltd.
Electric‐Field‐Directed Assembly of Biomolecular‐Derivatized Nanoparticles into Higher‐Order Structures
Authors: Dehlinger Dietrich A. , Sullivan Benjamin D. , Esener Sadik , Heller Michael J.
Published: June 2007

Multilayered structures composed of biomolecule‐derivatized nanoparticles can be fabricated by electric‐field‐directed self‐assembly. A microelectrode‐array device facilitates the rapid parallel electrophoretic transport and binding of biotin and streptavidin fluorescent nanoparticles to specific sites on the microarray. Control of the current, voltage, and activation time of each of the 400‐microarray electrodes allows a combinatorial approach to optimize nanoparticle binding. Under optimal conditions, nanoparticle layers form within 15 s of microelectrode activation, and the directed assembly of more than 50 alternate layers of nanoparticles is complete within an hour. The final multilayered structures are removed from the support by a relatively simple lift‐off process. The electric‐field process allows the parallel patterned assembly of multilayer structures using extremely low concentrations of nanoparticles and produces minimal nonspecific binding to unactivated sites. These results are significant for the development of rapid, maskless nanofabrication and hierarchical integration of biomolecular‐derivatized nanocomponents into higher‐order materials and devices.
Eine Dichtegleichung für Schwingungssysteme bei gleichzeitigen kontinuierlichen und diskreten stochastischen Erregungen
Authors: Renger A.
Published: June 2007

Für Schwingungssysteme, die gleichzeitig durch Gaußsches Weißes Rauschen und durch Impulsprozesse erregt werden, wird eine partielle Integrodifferentialgleichung für die Wahrscheinlichkeitsdichte der Systemantwort hergeleitet. Die Gleichung kann als Verallgemeinerung der Fokker‐Planck‐Gleichung auf Markov‐Prozesse, die keine Diffusionsprozesse darstellen, interpretiert werden. Am Beispiel des einfachen Tiefpasses sowie eines durch shot‐noise in Längsrichtung parametererregten Balkens werden erste Untersuchungen auf der Grundlage dieser Gleichung vorgeführt.
Behandlung eines stochastischen Steuerproblems mit Hilfe eines abstrakten Maximumprinzips von Spremann
Authors: Müller H.‐O.
Published: June 2007

In der Arbeit wird mit Hilfe des abstrakten Optimalitätsprinzips von Spremann ein stochastisches Maximumprinzip für Steuerprobleme bewiesen, deren Bewegungsgleichung die Gestalt

equation image

über einem festen Zeitintervall [t0, t1] besitzt. Z ist dabei ein stochastischer Prozeß, der die zufälligen Parameter des Systems repräsentiert, und die Steuerung U wird in Abhängigkeit von den unvollständigen Beobachtungen der Prozesse φ, Z und des Wiener‐Prozesses W gewählt. Das Maximumprinzip hat die Form einer Ungleichung der bedingten Erwartung einer Hamilton‐Funktion bezüglich der σ‐Algebra der vorliegenden Informationen. Die Hamilton‐Funktion entspricht dabei strukturell dem deterministischen Fall.
Unsteady Combined Convection from an Isothermal Circular Cylinder
Authors: Katagiri M. , Pop I.
Published: June 2007

An investigation is made of the heat transfer by combined free and forced convection from an isothermal circular cylinder in an unsteady stream of viscous incompressible fluid. Numerical solutions of unsteady boundary layer equations are sought by employing the local non‐similarity solution method (see Ref. [7]), together with difference‐differential method. In particular, the development of the boundary layer flow, the skin friction and heat transfer coefficients at the front stagnation point are examined. The numerical solution is compared with previous numerical work on the problem.
Zur Struktur der Gleichungen der Elastokinetik und Elastostabilität
Authors: Bufler H.
Published: June 2007

Ausgehend von D'Alembertschen Prinzip und seinen für eine gemischte Formulierung erforderlichen Erweiterungen werden die entsprechenden Variationsgleichungen für die inkrementellen Größen entwickelt. Diese dienen als Grundlage für die approximative Lösung kontinuierlicher Schwingungs‐ und Stabilitätsaufgaben und führen zu den Lagrangeschen Gleichungen 2. Art des diskreten Ersatzsystems und ihren Erweiterungen. Die Symmetrien der dabei entstehenden Matrizen beruhen auf der Potentialeigenschaft der Operatoren der nichtlinearen Ausgangsdifferentialgleichungen.
Random Vibration and Stability of a Linear Parametrically Excited Oscillator
Authors: Ariaratnam S. T. , Tam D. S. F.
Published: June 2007

The random vibration and stability of a linear second‐order oscillator subjected to both parametric and forced excitations of small intensity are investigated. Using a method of stochastic averaging, the steady‐state values of the response amplitudes as well as conditions for moment and sample stability are obtained. The first‐passage problem for envelope crossing is also examined.
Free Convection Boundary Layer on a Flat Plate due to Small Fluctuations in Surface Temperature
Authors: Muhuri P. K. , Gupta A. S.
Published: June 2007

Using the method of matched asymptotic expansions the unsteady free convection boundary layer flow past a vertical flat plate is obtained when the plate temperature oscillates about a non‐zero mean. It is found that when the Prandtl number is not unity, the solution far downstream reveals a double boundary layer, the inner layer being a shear layer having a double‐deck structure. The skin‐friction has a phase lag π/4 and the wall heat transfer has a phase lead π/4 over that of the surface temperature oscillations.
Weitere Konvergenzkriterien für das Gauß‐Seidel‐Verfahren
Authors: Albrand H.‐J.
Published: June 2007

In dieser Arbeit werden Zeilen‐ und Spaltensummennormen zweier Iterationsmatrizen exakt berechnet und naheliegende Abschätzungen de Matrixnormen und des Spektralradius hergeleitet. Diese Abschätzungen ergeben einige einfach strukturierte Konvergenzkriterien für das Gauß‐Seidel‐Verfahren zur Lösung linearer Gleichungssysteme. Die Arbeit enthält ferner einige Aussagen zur Schärfe der Abschätzungen, über Zusammenhänge zwischen den Abschätzungen, Fehlerabschätzungen und instruktive Beispiele.
Vergleich von Algorithmen für die Anpassung des Rechenmodells einer schwingungsfähigen elastomechanischen Struktur an Versuchswerte
Authors: Natke H. G.
Published: June 2007

Die Systemanalyse elastomechanischer Strukturen, basierend auf den Konstruktionszeichnungen, ergibt das Rechenmodell als Annäherung an die reale Struktur. Im allgemeinen weichen die mit Hilfe des Rechenmodells errechneten Werte von den Versuchswerten ab. Die Verbesserung des Rechenmodells durch die Korrektur der in Submatrizen zerlegten Steifigkeits‐ (Nachgiebigkeits‐)matrix anhand von gemessenen Eigenfrequenzen, Eigenfrequenzen und Eigenschwingungsformen, harmonischen Kräften und/oder zugehörigen dynamischen Antworten wird für ungedämpfte Strukturen behandelt. Die verschiedenen zur Korrektur verwendeten Versuchswerte führen auf unterschiedliche Verlustfunktionen für die Methode der gewichteten kleinsten Fehlerquadrate. Die sich ergebenden unterschiedlichen Anpassungsverfahren werden global miteinander verglichen. Als günstig erscheint die Verwendung von gemessenen stationären Antworten der Struktur und der eingeleiteten harmonischen Kräfte für die Verbesserung des Rechenmodells über die Anpassung der Kraftvektoren.
On Upper Bounds to Shakedown Loads
Authors: König Jan A.
Published: June 2007

Paper derives the general shakedown condition from kinematical considerations and shows that solutions of the incremental collapse problem, together with the alternating plasticity condition derived, constitute exact shakedown loads.
Auswirkungen von Rundungen und Näherungen bei einer Klasse iterativer Verfahren
Authors: Wildenauer P.
Published: June 2007

Der Einfluß auf das Konvergenzverhalten einer Iterationsfolge durch Rundungs‐ und evtl. Näherungsfehler, die bei jedem Iterationsschritt auftreten, wird untersucht. Dabei werden die zulässigen maximalen Fehler bei den einzelnen Iterationsschritten nicht als konstant vorausgesetzt. Die angegebenen Aussagen (Satz 1, Lemmata 2, 3) zur Fehler‐Analyse eignen sich für Verfahren, die in einem Bereich globale Konvergenz ergeben. Für diese ermöglichen sie die Fehler‐Analyse für jede in diesem Bereich gestartete Iterationsfolge. Die allgemeinen Sätze werden auf das Banachsche‐ und Newtonsche Iterationsverfahren angewandt. Die Arbeit ermöglicht eine wesentliche Einsparung von Rechenzeit. wenn die Approximationsgenauigkeit mit der Zahl der Iterationen gesteigert wird (siehe Abschnitt 5).
Monotone Difference Schemes for Diffusion‐Convection Problems
Authors: Stoyan Gisbert
Published: June 2007

Monotone difference schemes are considered (that is schemes for which the maximum principle holds) for diffusion‐convection problems modelled by (1) or by corresponding parabolic and two‐dimensional elliptic equations. The diffusion/convection ratio may be small or great, and a continuous connection is created between these two cases. For instance, in one of the variants a continuous transition is achieved from the Crank‐Nicholson‐scheme (applied if convection is zero) and a symmetric, second order Wendroff scheme (for the pure transport equation.) Numerical results for (1) show the efficiency of the method.
On the Convergence of a Mixed Finite Element Approximation for Cylindrical Shells
Authors: Talaslidis D.
Published: June 2007

Based on an extended Lax‐Milgram theorem the existence and uniqueness of mixed finite element approximations for cylindrical shells is proved. By use of certain theorems of matrix calculus a criterion for the choice of the interpolation functions is derived.
On a Griffith Crack at the Interface of two Bonded Dissimilar Elastic Wedges
Authors: Srivastava K. N. , Palaiya R. M. , Choudhary Arati
Published: June 2007

The stress field in the vicinity of a Griffith crack located at the interface of two bonded dissimilar wedges is determined. A systematic use of inverse Mellin transform reduces the problem to that of solving a set of simultaneous dual integral equations and this system in turn is shown to be equivalent to a Riemann boundary value problem with closed form solution. The particular case in which the crack is opened by constant pressure is discussed in detail. Expressions for the stress intensity factors at the crack tip are derived.
Lagrange‐Formalismus für diskrete elektromechanische Systeme
Authors: Maisser P. , Steigenberger J.
Published: June 2007

Es werden notwendige und hinreichende Bedingungen für die Existenz eines Lagrangeschen Models diskreter elektromechanischer Systeme (charakterisiert durch Kopplung von Starrkörpermechanik und Kirchhoff‐Theorie) formuliert. Bei Erfülltsein dieser Bedingungen werden das Lagrange‐Modell (Lagrange ‐ und Dissipationsfunktion) konstruiert und die Lagrangeschen Gleichungen explizit angegeben.
Thermal Stresses in an Infinite Plate with two Circular Inclusions under Uniform Heat Flow
Authors: Shioya Shunsuke , Matsuda Mitsumasa
Published: June 2007

In the present paper, we consider the problem of thermal stresses in an infinite plate with two circular inclusions, which are of different materials, under uniform heat flow. The analysis is developed on the basis of the Airy's stress function in the generalized plane stress and by applying bipolar coordinates. Here the plate is supposed to be insulated and the boundaries are free from the traction. Numerical calculations are worked out in some detail in order to clarify the effects of inclusions.
Catalyzed esterification of oleic acid
Authors: Dunlap L. H. , Heckles J. S.
Published: June 2007

Conclusions

It has been shown that the effectiveness of certain divalent metal salts as esterification catalysts can be quantitatively compared and that for the Group II B series their effectiveness is inversely proportional to their ionic volume. The rates of esterification using these metal salts are not as great as for strong acids, but it is probable that the mechanism is similar and that the metal salts act as acids in the general sense.

The rates of esterification differ appreciably for different primary polyols. It is also probable that these differences are related to the comparative acidity or basicity of the alcohols.

It would be particularly desirable to investigate the activity of the catalysts in different alcohols. It is possible that infrared studies might show formation of a complex between the catalyst and either the alcohol or the acid or both. A number of possibilities may be formulated; at present we lack critical evidence to distinguish between them and this area provides a fruitful field for further research.
Synthesis of amino acid derivatives of ethanolamine
Authors: Smith Elizabeth C. , Althouse P. M. , Shigley James W.
Published: June 2007

N‐Phthaloylglycylaminocthanol may be prepared in 24% yield by a modification of the Shechan carbodiimide synthesis of peptides of hydroxy amino acids (6). The amino alcohol is characterized as to melting point, solubility in various solvents, the ability to form a derivative with acetic anhydride, percentage of nitrogen, and infrared spectra. In acid solution this compound appears to undergo the aminoacyl shift characteristic of compounds containing an amide linkage and a free hydroxyl group. Attempts to isolated N‐glycylaminoethanol by hydrolysis of the phthaloyl derivative with hydrazine hydrate have been unsuccessful. Impure N‐phthaloylalanylaminoethanol and N‐phthaloylglycylglycylaminoethanol were also synthesized by means of this procedure. Several other methods for synthesizing N‐glycylaminoethanol are discussed.
Relationship between the apparent bulk density of a bleaching clay and its oil retention
Authors: Rich A. D.
Published: June 2007

Data have been presented which demonstrate that the inverse relationship is reasonably consistent between the apparent bulk density of a bleaching clay and its oil retention.
Preliminary report on a rapid method of evaluating detergency by means of an ultrasonic transducer
Authors: Sherrill Joseph C. , White W. Craig
Published: June 2007

Work on the magnitude of forces binding soils to textile surfaces has been described. In these studies an ultrasonic transducer has been used as a means for providing mechanical action of precisely controlled magnitude. Results have revealed energy requirements for any given level of soil removal. In addition, precision over existing methods of evaluation of detergents and detergency procedures is increased with considerable decrease in time of test.
Synthetic detergents from animal fats. VI. Polymerizable esters of alpha‐sulfonated fatty acids
Authors: Bistline R. G. , Stirton A. J. , Weil J. K. , Port W. S.
Published: June 2007

Sodium allyl α‐sulfopalmitate and sodium allyl α‐sulfostearate, prepared by esterification of an α‐sulfonated fatty acid with allyl alcohol, resemble sodium alkyl α‐sulfopalmitates and stearates in surface‐active and detergent properties and stability to hydrolysis.

The allyl esters are easily converted to a new type of water‐soluble polymer. The polymers may be thickening and emulsifying agents and may have other uses yet to be discovered.
Potential β‐sheet surfaces of soybean seed proteins
Authors: Rothfus John A.
Published: June 2007

Volume and amphiphilicity profiles computed for β‐sheet conformations of soybean seed proteins (the acidic and basic subunits of glycinin, the α subunit of β‐conglycinin, an extensin‐like high‐proline protein, and a lipid body oleosin) were compared to profiles for selected nonseed proteins and random‐sequence polypeptides. The major soy proteins resemble fibrinogen more than silk or collagen but are differentiated from each other by surface polarity. Polarity in acidic glycinin fluctuates somewhat regularly and symmetrically along both sides of the β‐sheet, but in basic glycinin, polarity on one side is fourfold that on the other throughout 70% of the protein. Polar residues distribute equally on either side of the β‐conglycinin subunit, but half of the acidic and basic residues concentrate in the N‐terminal third of the molecule. The remainder of the β‐conglycinin contains 90% of the molecule’s tyrosine, of which 70% is along one side. In the high‐proline protein, 90% of the tyrosine distributes to one side of a β‐sheet; 95% of the acidic residues to the other. Only soy oleosin approximates the per‐residue volume, polarity, and uniformity of silk or collagen. Its 85‐residue central lipophilic domain is much less polar than silk and nearly as uniform.
Interesterification kinetics of triglycerides and fatty acids with modified lipase inn‐hexane
Authors: Basheer Sobhi , Mogi Ken‐ichi , Nakajima Mitsutoshi
Published: June 2007

The kinetics of lipase‐catalyzed interesterification of triglycerides and fatty acids in organic media was studied. First, the lipase Saiken 100,Rhizopus japonicus, was modified by surfactant to form an enzyme precipitate in aqueous solution, which was well dispersed in organic solvents. This modified lipase catalyzed the interesterification of tripalmitin and stearic acid. The enzyme has 1,3‐positional specificity and does not distinguish between stearic and palmitic acids. The kinetic model developed to describe the interesterification reaction system is based on mass balance of two consecutive second‐order reversible reactions. The reaction rate constant, k, was determined by solving the differential rate equations of the reaction system and by expressing the value of k as a function of concentrations of the substrates with time. The model gave satisfactory results. The best value of the specific reaction rate constant k* that fits all experimental data was 1.2 · 10−5 [L2/(mmol · mg biocatalyst · h)] under the reaction conditions in this study.
Quantitation of flavor volatiles in oxidized soybean oil by dynamic headspace analysis
Authors: Lee Inmok , Fatemi Seyed H. , Hammond Earl G. , White Pamela J.
Published: June 2007

A dynamic headspace procedure was developed for isolating the volatiles from oxidized soybean oil and trapping them on an adsorbent under conditions that gave minimal decomposition of hydroperoxides (50°C for 30 min at a helium flow of 75 mL/min). The volatiles were desorbed from the adsorbent and separated by gas chromatography (GC) on a methyl silicone capillary column. Equations were derived from theoretical considerations that allowed the actual concentration of each flavor component in the oxidized oil to be calculated from the area of the GC peaks. The reliability of the method and calculations was demonstrated by recovery experiments. The concentration of 2‐heptanone in a mineral oil emulsion, equivalent in flavor intensity to each component, was calculated and summed to estimate the overall flavor intensity of the samples. The overall estimations were compared with the concentrations of 2‐heptanone observed to be equivalent in flavor intensity to the oxidized oil samples when these were tasted in emulsion. The concentrations of individual components calculated from the headspace volatiles data were all present at concentrations below their flavor thresholds, and the simple sum of the intensities of their flavors generally accounted for less than half of the flavor intensities of the oil samples. The differences in the headspace and sensory analyses might be attributed to the flavor of the unoxidized oil, synergistic interactions, and/or the presence of unmeasured flavors components.
Autoxidation kinetics for fatty acids and their esters
Authors: Adachi Shuji , Ishiguro Tatsuji , Matsuno Ryuichi
Published: June 2007

The autoxidation kinetics for n‐3 and n‐6 polyunsaturated fatty acids and their esters, which are collectively referred to as polyunsaturated fatty acids (PUFA), were investigated. Changes in the amounts of unreacted n‐6 PUFA during the entire period of autoxidation could be expressed by dY/dt−k1Y(1 −Y), wereY was the fraction of unreacted PUFA,t was the time, andk1 was the rate constant. For n‐3 PUFA, autoxidation had to be separated into two parts. The first half of autoxidation (Y ≥ 0.5) was expressed by the same equation as above, while the latter half (Y<0.5) relates to dY/dt=−k2Y, wherek2 was the rate constant. The apparent activation energies and the frequency factors ofk1 andk2 were evaluated. The apparent activation energies were in a range of 50 to 60 kJ/mol for bothk1 andk2. The frequency factor became large as the number of double bonds of PUFA increased.
Evaluation of antioxidants for cod liver oil by chemiluminescence and the rancimat method
Authors: Burkow Ivan C. , Vikersveen Line , Saarem Kristin
Published: June 2007

Commercial blends of natural antioxidants,viz., tocopherol concentrates, rosemary extracts, sage extracts, and lecithins, were tested for their ability to stabilize cod liver oil. The antioxidants were tested by using the Rancimat apparatus at 80°C and by a method based on hypochlorite‐activated chemiluminescence analysis of samples stored at 35°C for 24 h in light. In addition, a stability study at 5°C in the dark for 8 wk, under conditions realistic for normal consumption of cod liver oil was carried out. A low correlation (r=0.339) was found between Rancimat induction times and chemiluminescence data for the sixteen antioxidant systems tested, probably due to temperature differences, and different ways of detecting oxidation products. Based on Rancimat induction times, δ‐tocopherol‐rich antioxidants and lecithin had the best stabilizing effect. However, based on the chemiluminescence method, the tocopherols acted as prooxidants, while tocopherols with lecithin increased the stability. Both Racimat and chemiluminescence data showed stabilizing effects with rosemary and sage extracts, but no synergistic effect between the herbal extracts and lecithin or tocopherol was observed. Analyses of oil aged at 5°C for 8 wk showed the highest stability for cod liver oil containing rose‐mary extracts. The tocopherol mixtures showed only a minor effect on the stability. Ranking of antioxidants varied considerably depending on the method used, and increasing the temperature seemed to decrease the usefulness of the method. Antioxidant evaluation has to be done by using as many evaluation methods as possible under conditions relevant for normal storage and use.