bluuebunny/crossref_metadata_2025_split huggingface dataset:
On Projectively Flat (α, β)-metrics
Authors: Shen Zhongmin 
Published: October 2009

AbstractThe solutions to Hilbert's Fourth Problem in the regular case are projectively flat Finsler metrics. In this paper, we consider the so-called (α, β)-metrics defined by a Riemannian metric α and a 1-form β, and find a necessary and sufficient condition for such metrics to be projectively flat in dimensionn≥ 3.
The Waring Problem with the Ramanujan τ -Function, II
Authors: Garaev M. Z. , Garcia V. C. , Konyagin S. V. 
Published: October 2009

AbstractLet τ (n) be the Ramanujan τ -function. We prove that for any integer N with |N| ≥ 2 the diophantine equationhas a solution in positive integers n1, n2, … , n148000 satisfying the conditionfor some absolute constant c > 0.
Schubert Calculus on a Grassmann Algebra
Authors: Gatto Letterio , Santiago Taíse 
Published: October 2009

AbstractThe (classical, small quantum, equivariant) cohomology ring of the grassmannian G(k, n) is generated by certain derivations operating on an exterior algebra of a free module of rank n (Schubert calculus on a Grassmann algebra). Our main result gives, in a unified way, a presentation of all such cohomology rings in terms of generators and relations. Using results of Laksov and Thorup, it also provides a presentation of the universal factorization algebra of a monic polynomial of degree n into the product of two monic polynomials, one of degree k.
Equations and Complexity for the Dubois–Efroymson Dimension Theorem
Authors: Ghiloni Riccardo 
Published: October 2009

AbstractLetRbe a real closed field, letX⊂Rnbe an irreducible real algebraic set and letZbe an algebraic subset ofXof codimension ≥ 2. Dubois and Efroymson proved the existence of an irreducible algebraic subset ofXof codimension 1 containingZ. We improve this dimension theorem as follows. Indicate by μ the minimum integer such that the ideal of polynomials inR[x1, … ,xn] vanishing onZcan be generated by polynomials of degree ≤ μ. We prove the following two results: (1) There exists a polynomialP∈R[x1, … ,xn] of degree≤ μ+1 such thatX∩P–1(0) is an irreducible algebraic subset ofXof codimension 1 containingZ. (2) LetFbe a polynomial inR[x1, … ,xn] of degreedvanishing onZ. Suppose there exists a nonsingular pointxofXsuch thatF(x) = 0 and the differential atxof the restriction ofFtoXis nonzero. Then there exists a polynomialG∈R[x1, … ,xn] of degree ≤ max﹛d, μ + 1﹜ such that, for eacht∈ (–1, 1) \ ﹛0﹜, the set ﹛x∈X|F(x) +tG(x) = 0﹜ is an irreducible algebraic subset ofXof codimension 1 containingZ. Result (1) and a slightly different version of result (2) are valid over any algebraically closed field also.
Extensions of Rings Having McCoy Condition
Authors: Koşan Muhammet Tamer 
Published: October 2009

AbstractLet R be an associative ring with unity. Then R is said to be a right McCoy ring when the equation f (x)g(x) = 0 (over R[x]), where 0 ≠ f (x), g(x) ∈ R[x], implies that there exists a nonzero element c ∈ R such that f (x)c = 0. In this paper, we characterize some basic ring extensions of right McCoy rings and we prove that if R is a right McCoy ring, then R[x]/(xn) is a right McCoy ring for any positive integer n ≥ 2.
On Functions Whose Graph is a Hamel Basis, II
Authors: Płotka Krzysztof 
Published: October 2009

AbstractWe say that a functionh: ℝ → ℝ is a Hamel function (h∈ HF) ifh, considered as a subset of ℝ2, is a Hamel basis for ℝ2. We show that A(HF) ≥ ω,i.e.,for every finiteF⊆ ℝℝthere existsf∈ ℝℝsuch thatf+F⊆ HF. From the previous work of the author it then follows that A(HF) = ω.
Covering Discs in Minkowski Planes
Authors: Martini Horst , Spirova Margarita 
Published: October 2009

AbstractWe investigate the following version of the circle covering problem in strictly convex (normed or) Minkowski planes: to cover a circle of largest possible diameter bykunit circles. In particular, we study the casesk= 3,k= 4, andk= 7. Fork= 3 andk= 4, the diameters under consideration are described in terms of side-lengths and circumradii of certain inscribed regular triangles or quadrangles. This yields also simple explanations of geometric meanings that the corresponding homothety ratios have. It turns out that basic notions from Minkowski geometry play an essential role in our proofs, namely Minkowskian bisectors,d-segments, and the monotonicity lemma.
Numerical Semigroups That Are Not Intersections ofd-Squashed Semigroups
Authors: Moreno M. A. , Nicola J. , Pardo E. , Thomas H. 
Published: October 2009

AbstractWe say that a numerical semigroup isd-squashedif it can be written in the formforN,a1, … ,adpositive integers with gcd(a1, … ,ad) = 1. Rosales and Urbano have shown that a numerical semigroup is 2-squashed if and only if it is proportionally modular.Recent works by Rosaleset al.give a concrete example of a numerical semigroup that cannot be written as an intersection of 2-squashed semigroups. We will show the existence of infinitely many numerical semigroups that cannot be written as an intersection of 2-squashed semigroups. We also will prove the same result for 3-squashed semigroups. We conjecture that there are numerical semigroups that cannot be written as the intersection ofd-squashed semigroups for any fixedd, and we prove some partial results towards this conjecture.
On L1-Convergence of Fourier Series under the MVBV Condition
Authors: Yu Dan Sheng , Zhou Ping , Zhou Song Ping 
Published: October 2009

AbstractLet f ∈ L2π be a real-valued even function with its Fourier series , and let Sn( f , x), n ≥ 1, be the n-th partial sum of the Fourier series. It is well known that if the nonnegative sequence ﹛an﹜ is decreasing and limn→∞an = 0, thenWe weaken the monotone condition in this classical result to the so-called mean value bounded variation (MVBV) condition. The generalization of the above classical result in real-valued function space is presented as a special case of the main result in this paper, which gives the L1-convergence of a function f ∈ L2π in complex space. We also give results on L1-approximation of a function f ∈ L2π under the MVBV condition.
Palladium on Charcoal as a Recyclable Catalyst for CS Cross‐Coupling of Thiols with Aryl Halides under Ligand‐Free Conditions
Authors: Jiang Zheng , She Jin , Lin Xufeng 
Published: October 2009

AbstractS‐Arylation of a wide variety of substituted aryl and aliphatic thiols with aryl halides using a catalytic amount of palladium on charcoal as a heterogeneous catalysis with potassium hydroxide as the base in dimethyl sulfoxide (DMSO) at 110 °C is accomplished in good yields. The CS bond formation reaction functions under ligand‐free conditions, and the palladium on charcoal catalyst can be is reused for five runs without any loss of activity.
Accelerated Heck reaction using ortho‐palladated complex with controlled microwave heating
Authors: Hajipour Abdol R. , Karami Kazem , Pirisedigh Azadeh 
Published: October 2009

AbstractPalladium‐catalyzed Heck couplings utilizing [Pd{C6H2(CH2CH2NH2)‐(OMe)2,3,4} (µ‐Br)]2 palladacycle catalyst and microwave irradiation lead to formation of different coupling products. This complex is an active and efficient catalyst for the Heck reaction of aryl iodides, bromides and even less reactive chlorides. The cross‐coupled products were produced in excellent yields. The reaction time was reduced from hours to minutes and full conversion was achieved under microwave irradiation. Copyright © 2009 John Wiley & Sons, Ltd.
Preparation and properties of polyhedral oligomeric silsesquioxane–polysiloxane copolymers
Authors: Gunji Takahiro , Shioda Takahiro , Tsuchihira Koji , Seki Hiroyasu , Kajiwara Takashi , Abe Yoshimoto 
Published: October 2009

AbstractAll siloxane‐type siloxane–polyhedral oligomeric silsesquioxane [(HSiO3/2)8, T8H] copolymers were synthesized by the dehydrogenative condensation of T8H with diphenylsilanediol, tetraphenyldisiloxane‐1,3‐diol or silanol‐terminated polydimethylsiloxanes in the presence of diethylhydroxylamine followed by trimethylsilylation. Coating films were prepared by spin‐coating of the coating solutions prepared from the dehydrogenative condensation products. The hardness of the coating films was evaluated by a pencil hardness test and was found to increase up to 6H with increases in the curing temperature. Silica gels were prepared by concentrating the coating solution following by pyrolysis. These silica gels showed a specific surface area 449 m2/g at 650 °C corresponding to the formation of a silica network in response to combustion of the phenyl groups. Copyright © 2009 John Wiley & Sons, Ltd.
Ecdysteroid receptor (EcR) is associated with microtubules and with mitochondria in the cytoplasm of prothoracic gland cells of Rhodnius prolixus (Hemiptera)
Authors: Vafopoulou Xanthe 
Published: October 2009

AbstractWe have shown previously that EcR in larval Rhodnius is present in the cytoplasm of various cell types and undergoes daily cycling in abundance in the cytoplasm (Vafopoulou and Steel, 2006. Cell Tissue Res 323:443–455). It is unknown which organelles are associated with EcR. Here, we report that cytoplasmic EcR in prothoracic gland cells is associated with both microtubules and mitochondria, and discuss the implications for both nuclear and non‐genomic actions of EcR. EcR was localized immunohistochemically using several antibodies to EcR of Manduca and Drosophila and a confocal laser scanning microscope. Double labels were made to visualize EcR and (1) microtubules (using an antibody to tyrosylated α‐tubulin) and (2) mitochondria (using a fluorescent MitoTracker probe), both after stabilization of microtubules with taxol. EcR co‐localized with both tubulin and mitochondria. All the different EcR antibodies produced similar co‐localization patterns. EcR was seen in the perinuclear aggregation of mitochondria, indicating that mitochondria are targets of ecdysone, which could influence mitochondrial gene transcription. EcR was also distributed throughout the microtubule network. Co‐localization of EcR with tubulin or mitochondria was maintained after depolymerization of microtubules with colchicine. Treatment with taxol resulted in accumulation of EcR in the cytoplasm and simultaneous depletion of EcR from the nucleus, suggesting that microtubules may be involved in targeted intracellular transport of EcR to the nucleus (genomic action) or may play a role in rapid ecdysone signal transduction in the extranuclear compartment, i.e., in non‐genomic actions of ecdysone. These findings align EcR more closely with steroid hormone receptors in vertebrates. © 2009 Wiley Periodicals, Inc.
Implementing loss distribution approach for operational risk
Authors: Shevchenko Pavel V. 
Published: October 2009

AbstractIn order to quantify the operational risk capital charge under the current regulatory framework for banking supervision, referred to as Basel II, many banks adopt the loss distribution approach. There are many modeling issues that should be resolved to use this approach in practice. In this paper we review the quantitative methods suggested in the literature for the implementation of the approach. In particular, the use of Bayesian inference that allows one to take expert judgement and parameter uncertainty into account, modeling dependence, and inclusion of insurance are discussed. Copyright © 2009 John Wiley & Sons, Ltd.
Transient expression of human TorsinA enhances secretion of two functionally distinct proteins in cultured Chinese hamster ovary (CHO) cells
Authors: Jossé Lyne , Smales C. Mark , Tuite Mick F. 
Published: October 2009

AbstractCultured mammalian cells, particularly Chinese hamster ovary (CHO) cells, are widely exploited as hosts for the production of recombinant proteins, but often yields are limiting. Such limitations may be due in part to the misfolding and subsequent degradation of the heterologous proteins. Consequently we have determined whether transiently co‐expressing yeast and/or mammalian chaperones that act to disaggregate proteins, in CHO cell lines, improve the levels of either a cytoplasmic (Fluc) or secreted (Gluc) form of luciferase or an immunoglobulin IgG4 molecule. Over‐expression of the yeast ‘protein disaggregase’ Hsp104 in a CHO cell line increased the levels of Fluc more significantly than for Gluc although levels were not further elevated by over‐expression of the yeast or mammalian Hsp70/40 chaperones. Over‐expression of TorsinA, a mammalian protein related in sequence to yeast Hsp104, but located in the ER, significantly increased the level of secreted Gluc from CHO cells by 2.5‐fold and to a lesser extent the secreted levels of a recombinant IgG4 molecule. These observations indicate that the over‐expression of yeast Hsp104 in mammalian cells can improve recombinant protein yield and that over‐expression of TorsinA in the ER can promote secretion of heterologous proteins from mammalian cells. Biotechnol. Bioeng. 2010; 105: 556–566. © 2009 Wiley Periodicals, Inc.
Triple light chain antibodies: Factors that influence its formation in cell culture
Authors: Gomez Natalia , Vinson Abigail R. , Ouyang Jun , Nguyen Mary D.H. , Chen Xiaoying‐Nancy , Sharma Vikas K. , Yuk Inn H. 
Published: October 2009

AbstractTHIOMABs are recombinant antibodies engineered with reactive cysteines, which can be covalently conjugated to drugs of interest to generate targeted therapeutics. During the analysis of THIOMABs secreted by stably transfected Chinese Hamster Ovary (CHO) cells, we discovered the existence of a new species—Triple Light Chain Antibody (3LC). This 3LC species is the product of a disulfide bond formed between an extra light chain and one of the engineered cysteines on the THIOMAB. We characterized the 3LC by size exclusion chromatography, mass spectrometry, and microchip electrophoresis. We also investigated the potential causes of 3LC formation during cell culture, focusing on the effects of free light chain (LC) polypeptide concentration, THIOMAB amino acid sequence, and glutathione (GSH) production. In studies covering 12 THIOMABs produced by 66 stable cell lines, increased free LC polypeptide expression—evaluated as the ratio of mRNA encoding for LC to the mRNA encoding for heavy chain (HC)—correlated with increased 3LC levels. The amino acid sequence of the THIOMAB molecule also impacted its susceptibility to 3LC formation: hydrophilic LC polypeptides showed elevated 3LC levels. Finally, increased GSH production—evaluated as the ratio of the cell‐specific production rate of GSH (qGSH) to the cell‐specific production rate of THIOMAB (qp)—corresponded to decreased 3LC levels. In time‐lapse studies, changes in extracellular 3LC levels during cell culture corresponded to changes in mRNA LC/HC ratio and qGSH/qp ratio. In summary, we found that cell lines with low mRNA LC/HC ratio and high qGSH/qp ratio yielded the lowest levels of 3LC. These findings provide us with factors to consider in selecting a cell line to produce THIOMABs with minimal levels of the 3LC impurity. Biotechnol. Bioeng. 2010. 105: 748–760. © 2009 Wiley Periodicals, Inc.
Quality of life after surgical reduction for severe primary lymphoedema of the limbs and genitalia
Authors: Ogunbiyi S O , Modarai B , Smith A , Burnand K G 
Published: October 2009

Abstract

Background
The aim was to assess the quality of life (QoL) of patients who had surgery for primary lymphoedema.

Methods
A QoL questionnaire was administered to patients who had surgery between 1981 and 2003 (retrospective group) and between 2003 and 2006 (prospective group).

Results
The response rate was 70·3 per cent (109 of 155 patients): 88 patients had limb reduction (78, retrospective; ten, prospective) and 21 had genital reduction (13, retrospective; eight, prospective). Forty-nine patients (63 per cent) who had limb reduction studied retrospectively reported satisfaction with the procedure and most of these would opt for surgery again. In the prospectively studied group, nine of ten patients reported improved limbs, and seven would opt for surgery again. Nineteen of 21 patients who had genital reduction would choose to have surgery again if needed (11 of the retrospectively assessed group and all of the prospective group). Patients' perception that surgery was worthwhile was greater in both of the prospectively assessed groups (P = 0·013).

Conclusion
Surgery for severe lymphoedema improved QoL at early assessment. This, however, may not be sustained. Genital reduction appeared to provide greater benefit than limb reduction.
Genetic and environmental influences on the risk of acute appendicitis in twins
Authors: Sadr Azodi O , Andrén-Sandberg Å , Larsson H 
Published: October 2009

Abstract

Background
Acute appendicitis is common but the aetiology is unclear. This study examined the heritability of acute appendicitis.

Methods
The study included twin pairs with known zygosity born between 1959 and 1985. Individuals with acute appendicitis were found by record linkage with the Swedish Inpatient Register. Comparing monodizygotic and dizygotic twins, the similarity and relative proportions of phenotypic variance resulting from genetic and environmental factors were analysed. Risks of acute appendicitis explained by heritability and environmental effects were estimated.

Results
Some 3441 monozygotic and 2429 dizygotic twins were identified. Almost no genetic effects were found in males (8 (95 per cent confidence interval 0 to 50) per cent), but shared (31 (0 to 49) per cent) and non-shared (61 (47 to 74) per cent) environmental factors accounted for this risk. In females, the heritability was estimated as 20 (0 to 36) per cent and the remaining variation was due to non-shared environmental factors (80 (64 to 98) per cent). For the sexes combined, genetic effects accounted for 30 (5 to 40) per cent and non-shared environmental effects for 70 (60 to 81) per cent of the risk.

Conclusion
Acute appendicitis has a complex aetiology with sex differences in heritability and environmental factors.
Understanding environmental management practices: integrating views from strategic management and ecological economics
Authors: Lucas Marilyn T. 
Published: October 2009

AbstractThis paper proposes an integrating framework, based on theoretical concepts from the fields of strategic management and ecological economics, to enhance our understanding of environmental management practices (EMPs) and their relationship to sustainable competitive advantage. Starting with an expansion of the resource‐based view of the firm to include the natural environment, the article next engages the interdisciplinary field of ecological economics and its thermodynamic approach to ‘joint production’ to provide additional insights into the challenges and opportunities brought by a bio‐physically constrained economy. Informed by this understanding, the article then categorizes examples of EMPs drawn from the literature and discusses their potential impact on competitiveness. The paper concludes with a discussion of implications for future research in the hope that the proposed framework will stimulate debate and lead to a fuller understanding of the impact of environmental management in the 21st century. Copyright © 2009 John Wiley & Sons, Ltd and ERP Environment.
Molecular Mechanism of the Hydration of Candida antarctica Lipase B in the Gas Phase: Water Adsorption Isotherms and Molecular Dynamics Simulations
Authors: Branco Ricardo J. F. , Graber Marianne , Denis Vinciane , Pleiss Jürgen 
Published: October 2009

AbstractHydration is a major determinant of activity and selectivity of enzymes in organic solvents or in gas phase. The molecular mechanism of the hydration of Candida antarctica lipase B (CALB) and its dependence on the thermodynamic activity of water (aw) was studied by molecular dynamics simulations and compared to experimentally determined water sorption isotherms. Hydration occurred in two phases. At low water activity, single water molecules bound to specific water binding sites at the protein surface. As the water activity increased, water networks gradually developed. The number of protein‐bound water molecules increased linearly with aw, until at aw=0.5 a spanning water network was formed consisting of 311 water molecules, which covered the hydrophilic surface of CALB, with the exception of the hydrophobic substrate‐binding site. At higher water activity, the thickness of the hydration shell increased up to 10 Å close to aw=1. Above a limit of 1600 protein‐bound water molecules the hydration shell becomes unstable and the formation of pure water droplets occurs in these oversaturated simulation conditions. While the structure and the overall flexibility of CALB was independent of the hydration state, the flexibility of individual loops was sensitive to hydration: some loops, such as those part of the substrate‐binding site, became more flexible, while other parts of the protein became more rigid upon hydration. However, the molecular mechanism of how flexibility is related to activity and selectivity is still elusive.
Microwave‐Assisted Functionalization of Carbon Nanostructures in Ionic Liquids
Authors: Guryanov Ivan , Toma Francesca Maria , Montellano López Alejandro , Carraro Mauro , Da Ros Tatiana , Angelini Guido , D'Aurizio Eleonora , Fontana Antonella , Maggini Michele , Prato Maurizio , Bonchio Marcella 
Published: October 2009

AbstractThe effect of microwave (MW) irradiation and ionic liquids (IL) on the cycloaddition of azomethine ylides to [60]fullerene has been investigated by screening the reaction protocol with regard to the IL medium composition, the applied MW power, and the simultaneous cooling of the system. [60]Fullerene conversion up to 98 % is achieved in 2–10 min, by using a 1:3 mixture of the IL 1‐methyl‐3‐n‐octyl imidazolium tetrafluoroborate ([omim]BF4) and o‐dichlorobenzene, and an applied power as low as 12 W. The mono‐ versus poly‐addition selectivity to [60]fullerene can be tuned as a function of fullerene concentration. The reaction scope includes aliphatic, aromatic, and fluorous‐tagged (FT) derivatives. MW irradiation of IL‐structured bucky gels is instrumental for the functionalization of single‐walled carbon nanotubes (SWNTs), yielding group coverages of up to one functional group per 60 carbon atoms of the SWNT network. An improved performance is obtained in low viscosity bucky gels, in the order [bmim]BF4> [omim]BF4> [hvim]TF2N (bmim=1‐methyl‐3‐n‐butyl imidazolium; hvim=1‐vinyl‐3‐n‐hexadecyl imidazolium). With this protocol, the introduction of fluorous‐tagged pyrrolidine moieties onto the SWNT surface (1/108 functional coverage) yields novel FT‐CNS (carbon nanostructures) with high affinity for fluorinated phases.
Observing Second‐Order Nonlinear Optical Properties by Symmetry Breaking in Centrosymmetric Furan‐Containing Oligoaryl Cyclophandienes
Authors: Lin Hsin‐Chieh , Hsu Jui‐Hung , Lee Chao‐Kuei , Tai Oliver Yung‐Hui , Wang Chin‐Hsien , Chou Chih‐Ming , Chen Kuang‐Yen , Wu Yi‐Lin , Luh Tien‐Yau 
Published: October 2009

AbstractCentrosymmetric furan‐containing cyclophandienes 3 and 4, synthesized by our furan annulation protocol, have been shown to exhibit extraordinarily large Stokes shifts and second‐order nonlinear optical β values. The β values for 3 and 4 measured at 1.32 μm are 208 and 530×10−30 esu, respectively. The β values of 3 and 4 are similar to those of respective cyclophenes 1 a and 7 in which strong hyperpoarizable interactions between two twisted π‐systems (oligoaryl and bridging double bond) might take place. Symmetry breaking due to the resonance contribution (cf. 2) and the unique structural features of 3 and 4 has been used to account for this unusual photophysical behavior.
Synthesis of N‐Substituted‐2‐Aminobenzothiazoles by Ligand‐Free Copper(I)‐Catalyzed Cross‐Coupling Reaction of 2‐Haloanilines with Isothiocyanates
Authors: Shen Guodong , Lv Xin , Bao Weiliang 
Published: October 2009

AbstractA novel and efficient formation of N‐substituted‐2‐aminobenzothiazoles by a ligand‐free copper(I)‐catalyzed one‐pot cascade process was developed. A variety of isothiocyanates coupled with 2‐iodoanilines to give N‐substituted‐2‐aminobenzothiazoles in moderate to excellent yields under mild conditions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)