bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure stability of the α‐helix structure in a de novo designed protein (α‐l‐α)2 studied by FTIR spectroscopy
Authors: Takekiyo Takahiro , Takeda Naohiro , Isogai Yasuhiro , Kato Minoru , Taniguchi Yoshihiro 
Published: November 2006

AbstractThe pressure‐induced structural changes of a de novo designed four‐helix bundle protein, (α‐l‐α)2, in aqueous solution have been investigated by FTIR spectroscopy. Changes in the amide I' band intensity show that pressure induces disruption of tertiary interactions and stabilizes the solvated α‐helical form. This may suggest that the exposure of the hydrophobic core to the solvent by pressure is not a sufficient condition for pressure‐induced unfolding of the α‐helices of proteins. © 2006 Wiley Periodicals, Inc. Biopolymers 85:185–188, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Differential recognition of natural and nonnatural substrate by molecular chaperone α‐crystallin—A subunit exchange study
Authors: Biswas Ashis , Das K. P. 
Published: November 2006

Abstractα‐Crystallin is a molecular chaperone that recognizes proteins substrates in stress. It binds to the unstable conformer of a large variety of related or unrelated substrates and thus prevents them aggregating and holds them in a folding competent state. In this article, we have tried to critically analyze, from experimental point of view, whether α‐crystallin has any preference for its natural substrates compared to the nonnatural one. Our results clearly show that α‐crystallin is exceptionally active and sensitive in preventing aggregation of its natural substrates and can fully prevent such an aggregation in a substoichiometric ratio, but nonnatural substrates require a considerably higher amount of α‐crystallin. Using suitable fluorescent‐labeled α‐crystallins and performing fluorescence resonance energy transfer experiments, we were able to determine the subunit exchange kinetics between the α‐crystallin oligomers. It was found that while α‐crystallin was bound to its natural substrate, the rate of subunit exchange was slightly decreased. But, when a nonnatural substrate carbonic anhydrase remained bound to the chaperone, further loss in subunit exchange rate was observed. Nonnatural substrate was found to create higher activation energy barrier for the subunit exchange reaction compared to the native substrates. Similarities in major β‐sheet structure of both α‐crystallin and its natural substrates may be the reason for the preference in molecular recognition in comparison with the nonnatural substrate. © 2006 Wiley Periodicals, Inc. Biopolymers 85:189–197, 2007.This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Solvent‐free enzymatic synthesis of fatty alkanolamides
Authors: Tufvesson Pär , Annerling Annika , Hatti‐Kaul Rajni , Adlercreutz Dietlind 
Published: November 2006

AbstractAn environmentally benign and volume efficient process for enzymatic production of alkanolamides is described. Immobilized Candida antarctica lipase B, Novozym®435, was used to catalyze the condensation of lauric acid with monoethanolamine. The reaction temperature of 90°C was required to keep the reactants in a liquid state. Stepwise addition of the amine minimized problems caused by the formation of a highly viscous amine/fatty acid ion‐pair. The enzyme was both very active and stable under the reaction conditions, with about half of the activity remaining after 2 weeks. The maximum amide yield obtained when using equimolar amounts of the reactants was 75%, which could be increased to 95% upon water removal. Special precautions to avoid co‐distillation of the amine were required. Two different strategies to avoid the amine loss are presented. Biotechnol. Bioeng. 2007;97: 447–453. © 2006 Wiley Periodicals, Inc.
Determination of the origin of the N‐terminal pyro‐glutamate variation in monoclonal antibodies using model peptides
Authors: Dick Lawrence W. , Kim Catherine , Qiu Difei , Cheng Kuang‐Chuan 
Published: November 2006

AbstractThe purpose of this work is to determine the cause of the cyclization of the N‐terminal glutamine in recombinant proteins and monoclonal antibodies. This cyclization reaction commonly occurs on the N‐terminal of light and/or heavy chains of antibodies and leads to heterogeneity of the final product. Two model peptides and an antibody containing an N‐terminal glutamine were used to investigate the formation of N‐terminal pyro‐ glutamic acid under various experimental conditions and different stages of the biosynthetic process. LC–MS analysis was used to separate and quantify the N‐terminal variants. Experiments prove that the cyclization reaction is spontaneous and highly dependent on temperature and buffer composition and less dependent on pH. The conditions presented in most biopharmaceutical processes accelerate the formation of this variant. The majority of the near complete conversion (>95%) of N‐terminal glutamine to pyro‐glutamic acid commonly observed for antibodies appears to occur inside the bioreactor with only a small contribution from purification, formulation, and analytical preparation. Biotechnol. Bioeng. 2007;97: 544–553. © 2006 Wiley Periodicals, Inc.
Impact of neonatal imprinting with vitamin A or D on the hormone content of rat immune cells
Authors: Csaba György , Kovács Peter , Pállinger Éva 
Published: November 2006

AbstractNeonatal single vitamin A (retinol; 3 mg) or vitamin D3(cholecalciferol; 0.05 mg) treatment (imprinting) was done in male and female rats and 2 months later the endorphin, triiodothyronine (T3) and ACTH content of immune cells (peritoneal lymphocytes, monocyte‐granulocyte‐macrophage group [mo‐gran], mast cells and thymic lymphocytes) were studied immunocytochemically by using flow cytometry and confocal microscopy. The T3content was significantly decreased in peritoneal lymphocytes and in mo‐gran and the endorphin content decreased in thymocytes of male animals, while ACTH was decreased in female lymphocytes and mo‐gran. Vitamin D treatment was absolutely ineffective. The imprinting effects of vitamins A and D and their differences are discussed. The results call attention to the possible harmful effect of vitamin treatments during the perinatal critical period. Copyright © 2006 John Wiley & Sons, Ltd.
Unprecedented Polymerization of Trimethylene Carbonate Initiated by a Samarium Borohydride Complex: Mechanistic Insights and Copolymerization with ε‐Caprolactone
Authors: Palard Isabelle , Schappacher Michèle , Belloncle Benjamine , Soum Alain , Guillaume Sophie M. 
Published: November 2006

AbstractPoly(trimethylene carbonate) (PTMC) was synthesized through ring‐opening polymerization by using a rare‐earth borohydride initiator, [Sm(BH4)3(thf)3]. This initiator shows a high activity to give high‐molar‐mass PTMCs with molar‐mass distributions ranging from 1.2 to 1.4, and with a regular structure void of ether linkages. The polymers were characterized by 1H and 13C NMR spectroscopy, 1H‐1H COSY, 1H‐13C HMQC NMR spectroscopy, size‐exclusion chromatography (SEC), viscosimetry, and MALDI‐TOF MS analyses. A coordination‐insertion mechanism was established based on detailed NMR characterizations, especially of the polymer chain end‐functions. The monomer initially coordinates the samarium to give [Sm(BH4)3(tmc)3], 1. The monomer then opens up through cleavage of the cyclic ester oxygenacyl bond and inserts into the SmHBH3 bond resulting in an alkoxide complex, [Sm{O(CH2)3OC(O)HBH3}3], 2, or [Sm{O(CH2)3OC(O)H}3], 2′, which then propagates the polymerization of TMC to give the active polymer [Sm({O(CH2)3OC(O)}nO(CH2)3OC(O)HBH3)3], 3 or [Sm(O(CH2)3OC(O){O(CH2)3OC(O)}nO(CH2)3OC(O)H)3], 3′. Finally, acidic hydrolysis of 3 or 3′ gives HO(CH2)3OC(O)[O(CH2)3OC(O)]nO(CH2)3OC(O)H, 4. This novel α‐hydroxy,ω‐formatetelechelic PTMC represents the first example of a formate‐terminated polycarbonate. TMC and ε‐caprolactone (CL) were copolymerized to afford both random PTMC‐co‐PCL and block PTMC‐b‐PCL copolymers that were characterized by 1H NMR spectroscopy, SEC, and differential scanning calorimetry (DSC). The structure of the block copolymers depends on the order of addition of monomers: if CL is introduced first, dihydroxytelechelic HO‐PTMC‐b‐PCL‐OH polymers are formed, whereas introduction of TMC first or simultaneous addition of comonomers leads to hydroxyformatetelechelic HC(O)O‐PTMC‐b‐PCL‐OH analogues.
Coordination of Triply Charged Lanthanum in the Gas Phase: Theory and Experiment
Authors: Shi Tujin , Hopkinson Alan C. , Siu K. W. Michael 
Published: November 2006

AbstractIon–molecule reactions between complexes [La(CH3CN)n]3+ (n=6–9) or [La(NC(CH2)4CN)n]3+ (n=3–4) and water were studied at low collision energies in the second quadrupole of a tandem mass spectrometer. The products [La(CH3CN)p(H2O)8−p]3+ (p=6–8) and [La(NC(CH2)4CN)q(H2O)8−2q]3+ (q=3–4) had the highest relative abundances. This strongly suggests that the preferred coordination number of La3+ is eight. Similarly, the coordination number of Ca2+ was re‐examined both experimentally and theoretically, and was found to be six, in good agreement with previous observations. Density functional calculations provide strong evidence that the primary solvation shell of [La(L)n]3+ consists of eight ligands; additional ligands reside in a second solvation shell and are hydrogen bonded to one or two water molecules in the first shell.
Assessing the health care needs of adolescent and young adult cancer patients and survivors
Authors: Zebrack Brad , Bleyer Archie , Albritton Karen , Medearis Sandra , Tang Julia 
Published: November 2006

AbstractBACKGROUND.Improvements in cancer outcomes observed for the United States population as a whole are not experienced as such by adolescent and young adult (AYA) patients. The objective of this study was to identify important health and supportive care needs for AYA patients and survivors.METHODS.Forty oncology health professionals and 37 young adults (ages 18 years to 44 years; diagnosed between ages 15 years and 39 years) participated on a modified Delphi panel. Over 3 iterative rounds of mailed surveys, participants identified, rank ordered, and rated the importance of various items.RESULTS.Overall, there was general agreement among health care providers and young adult survivors, with some notable exceptions. Providers and young adult survivors agreed on the relative importance of having adequate health insurance and oncology care that addresses the unique developmental characteristics of this population. Compared with health professionals, young adults ranked the importance of opportunities to meet other young adult survivors at a relatively higher level, and they also ranked those opportunities higher than the importance of support from family and friends.CONCLUSIONS.These findings provide oncology professionals and young adults with insight into the others' values and perspectives. These findings also suggest areas in which to target investments of resources to promote quality health care and appropriate informational and supportive care services and to overcome the deficit in survival improvement that has occurred in young adults and older adolescents with cancer. Cancer 2006. © 2006 American Cancer Society.
Adaptive preconditioning of linear stochastic algebraic systems of equations
Authors: Feng Y. T. 
Published: November 2006

AbstractThis paper proposes an adaptively preconditioned iterative method for the solution of large‐scale linear stochastic algebraic systems of equations with one random variable that arise from the stochastic finite element modelling of linear elastic problems. Firstly, a Rank‐one posteriori preconditioner is introduced for a general linear system of equations. This concept is then developed into an effective adaptive preconditioning scheme for the iterative solution of the stochastic equations in the context of a modified Monte Carlo simulation approach. To limit the maximum number of base vectors used in the scheme, a simple selection criterion is proposed to update the base vectors. Finally, numerical experiments are conducted to assess the performance of the proposed adaptive preconditioning strategy, which indicates that the scheme with very few base vectors can improve the convergence of the standard Incomplete Cholesky preconditioning up to 50%. Copyright © 2006 John Wiley & Sons, Ltd.
On the improvement of a numerical method for solving high‐order non‐linear ordinary differential equations
Authors: Zhu Songping , Hammel Christian G. 
Published: November 2006

AbstractThere have been many approaches to solve ordinary differential equations numerically. Even though many numerical methods can provide very good approximate solutions they need considerable calculation effort, often through iterations. The advance of symbolic manipulation packages such as Maple gives the opportunity for new approaches to this type of problems. This paper will discuss an improvement to one of these new approaches enabled by the availability of these packages, to obtain a numerical solution of an initial‐value problem governed by a high‐order non‐linear ordinary differential equation. The method we propose here is based on Zhu and Phan's earlier paper (Commun. Numer. Meth. Engng. 2003; 19:601–614) but we shall show an improved order of accuracy for the case of the highest‐order derivative being of an even order. In any case it provides the ability to further increase the order of accuracy under certain conditions of differentiability. Like Zhu and Phan's (Commun. Numer. Meth. Engng. 2003; 19:601–614) original method, an important feature of the new method is that no iterations are needed except in the preparatory phase for some cases. Copyright © 2006 John Wiley & Sons, Ltd.
Two‐Photon Photochromism of a Diarylethene Enhanced by Förster Resonance Energy Transfer from Two‐Photon Absorbing Fluorenes
Authors: Belfield Kevin D. , Bondar Mykhailo V. , Corredor Claudia C. , Hernandez Florencio E. , Przhonska Olga V. , Yao Sheng 
Published: November 2006

AbstractResonance energy transfer from two‐photon absorbing fluorene derivatives to the photochromic compound 3,4‐bis‐(2,4,5‐trimethyl‐thiophen‐3‐yl)furan‐2,5‐dione (PC1) is investigated in hexane under one‐ and two‐photon excitation. The quenching of the steady‐state fluorescence of donor molecules in the presence of the diarylethene acceptor is used to study the nature of resonance energy transfer. The Förster distances and critical acceptor concentrations are determined for nonbound donor–acceptor pairs in homogeneous molecular ensembles. Quite significantly, up to a two‐fold enhancement in the velocity of the photochromic transformation of1, in the presence of two‐photon absorbing fluorene derivatives, is demonstrated.
Lactadherin detects early phosphatidylserine exposure on immortalized leukemia cells undergoing programmed cell death
Authors: Shi Jialan , Shi Yinan , Waehrens Lasse N. , Rasmussen Jan T. , Heegaard Christian W. , Gilbert Gary E. 
Published: November 2006

AbstractBackground:Phosphatidylserine (PS) appears on the outer membrane leaflet of cells undergoing programmed cell death and marks those cells for clearance by macrophages. Macrophages secrete lactadherin, a PS‐binding protein, which tethers apoptotic cells to macrophage integrins.Methods:We utilized fluorescein‐labeled lactadherin together with the benchmark PS Probe, annexin V, to detect PS exposure by flow cytometry and confocal microscopy. Immortalized leukemia cells were treated with etoposide, and the kinetics and topology of PS exposure were followed over the course of apoptosis.Results:Costaining etoposide‐treated leukemoid cells with lactadherin and annexin V indicated progressive PS exposure with dim, intermediate, and bright staining. Confocal microscopy revealed localized plasma membrane staining, then diffuse dim staining by lactadherin prior to bright generalized staining with both proteins. Annexin V was primarily localized to internal cell bodies at early stages but stained the plasma membrane at the late stage. Calibration studies suggested a PS content ≲2.5%–8% for the membrane domains that stained with lactadherin but not annexin V.Conclusions:Macrophages may utilize lactadherin to detect PS exposure prior to exposure of sufficient PS to bind annexin V. The methodology enables detection of PS exposure at earlier stages than established methodology. © 2006 International Society for Analytical Cytology
Quality evaluation of pseudorandom patterns of a logic BIST
Authors: Sato Yasuo , Nakao Michinobu 
Published: November 2006

AbstractFaults based on complex logic phenomena such as bridges, opens, and delays are increasing as microfabrication progresses and chips speeds increase. However, the capacity for detecting such faults with merely a test set, which has the goal of reducing the number of test patterns based on conventional single stuck‐at fault models, is not sufficient. This paper offers a multifaceted evaluation of the fault detection capacity of a logic BIST using pseudorandom patterns, based on the idea that the detection of such faults will be possible through the generation of combinations of diverse logic values with many test patterns. Through fault simulation for several fault models and the evaluation of a logic BIST using real devices, it is shown that it is possible to detect faults which could not be detected with a conventional scan test set. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 89(12): 63–70, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20323
Discrete‐time model following control of inverter with rectifier load
Authors: Umemura Atsushi , Haneyoshi Toshimasa , Saito Yukio , Harashima Funio 
Published: November 2006

AbstractElectronic apparatus, such as a computer, are a capacitor input type rectifier load for the power supply. The rectifier load causes distortions of the power source voltage waveform. Copyright © 2004 Wiley Periodicals, Inc.This paper describes the output voltage characteristic of the single phase PWM inverter controlled by a discrete‐time model following method and connected to a rectifier load. First, the rectifier load model of a discrete‐time system is considered. Next, the discrete‐time model following control system used for this load is described. Then, simulation and experimental results are examined. The simulation results show that this method has robustness to the load change. The experimental system consists of an inverter controlled by a digital signal processor (DSP) and a rectifier load. Experimental results confirmed the validity of the simulation result. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 72–81, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20375
Characteristics of N2/SF6mixture gas in creeping discharge developing in narrow gap with backside electrode
Authors: Hirata Tomoyuki , Ueno Hideki , Nakayama Hiroshi 
Published: November 2006

AbstractThe flashover voltage with a backside electrode was found to be lower than that without the backside electrode. Under microsecond pulse voltage application, we describe the characteristics of a creeping discharge developed in the narrow gap with the backside electrode. Using a CCD camera and ultrahigh‐speed camera, we observed the corona extension processes. The lowest flashover voltage was found to be obtained at positive polarity with a SF6contentD= 3%. In the corona extension obtained using an ultrahigh‐speed camera, peculiar differences were observed in the corona extension process. The corona extension increased, and rapid flashover was observed atD= 3%. Using a CCD camera, small coronas were detected from the backside electrode. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 31–38, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20431
Quantitative analysis of output loss due to restriction for grid‐connected PV systems
Authors: Ueda Yuzuru , Oozeki Takashi , Kurokawa Kosuke , Itou Takamitsu , Kitamura Kiyoyuki , Miyamoto Yusuke , Yokota Masaharu , Sugihara Hiroyuki 
Published: November 2006

AbstractThe voltage of power distribution lines will be increased due to reverse power flow from grid‐connected PV systems. In the case of high‐density grid connection, the voltage increase will be higher than in a stand‐alone grid connection system. To prevent overvoltage on the power distribution lines, the PV system's output will be restricted if the voltage of the power distribution line is close to the upper limit of the control range. Because of this interaction, the output loss will be larger in the high‐density case. This research has developed a quantitative analysis method for PV system output and losses in order to clarify the behavior of grid‐connected PV systems. All the measured data are classified into loss factors using a 1‐minute average of 1‐second data instead of the typical 1‐hour average. The operation point on the I–V curve is estimated to quantify the loss due to the output restriction, using the module temperature, array output voltage, array output current, and solar irradiance. As a result, the loss due to output restriction is successfully quantified and the behavior of output restriction is clarified. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 158(2): 9–19, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20452
Rare‐Earth Nitroquinolinates: Visible‐Light‐Sensitizable Near‐Infrared Emitters in Aqueous Solution
Authors: Van Deun Rik , Fias Pascal , Nockemann Peter , Van Hecke Kristof , Van Meervelt Luc , Binnemans Koen 
Published: November 2006

AbstractWater‐soluble, stable, and easily synthesizable 1:4 complexes of rare‐earth ions with 8‐hydroxy‐5‐nitroquinolinate ligands have been prepared. These complexes can be sensitized by visible light with wavelengths up to 480 nm and show near‐infrared emission in aqueous solution. The incorporation of a nitro group in the quinoline moiety shifts its absorption bands to longer wavelengths and also increases its molar absorptivity by a factor of 2.5, thereby significantly enhancing its light‐harvesting power. The presence of the nitro group also increases the solubility of the resulting complexes, making them water‐soluble. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Synthesis of γ‐Alkylidenebutenolides by Formal [3+2] Cyclizations of 1,5‐ and 2,4‐Bis(trimethylsilyloxy)‐1,3,5‐hexatrienes with Oxalyl Chloride
Authors: Freifeld Ilia , Bose Gopal , Eckardt Tobias , Langer Peter 
Published: November 2006

AbstractLewis acid‐catalyzed cyclizations of 1,5‐bis(trimethylsilyloxy)‐1,3,5‐hexatrienes and 1,3,5‐tris(trimethylsilyloxy)‐1,3,5‐hexatrienes with oxalyl chloride resulted in the formation of polyunsaturated γ‐alkylidenebutenolides, while the cyclization of a 2,4‐bis(trimethylsilyloxy)‐1,3,5‐hexatriene with oxalyl chloride afforded a γ‐(2‐oxobut‐3‐en‐1‐ylidene)butenolide, permitting a formal synthesis of the natural product lucidone. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Study of the Glycosidation Properties of 1‐Thiomannosazidopyranosides and 1‐Thiomannosaziduronic Acid Esters
Authors: van den Bos Leendert J. , Duivenvoorden Boudewijn A. , de Koning Martijn C. , Filippov Dmitri V. , Overkleeft Herman S. , van der Marel Gijsbert A. 
Published: November 2006

AbstractA study of the glycosylation properties of 1‐thiomannosazides with a variety of electron‐withdrawing substituents in combination with the Ph2SO/Tf2O and NIS/TMSOTf reagent systems is presented. Further, assembly of the fully protected trisaccharide 26, which corresponds to the repeating unit of the enterobacterial common antigen, using both an orthogonal and a chemoselective coupling strategy and based on the outcome of our glycosylation studies, is discussed. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)