bluuebunny/crossref_metadata_2025_split huggingface dataset:
Trypsin‐immobilized fiber core in syringe needle for highly efficient proteolysis
Authors: Wang Sheng , Chen Zhi , Yang Pengyuan , Chen Gang 
Published: April 2008

AbstractIn this report, a core‐changeable needle enzymatic reactor was developed for highly efficient proteolysis. A piece of enzyme‐immobilized fiber core was inserted into the needle of a syringe pump to form a flow‐through bioreactor. The novel in‐needle bioreactor could be regenerated by changing its fiber core. The feasibility and performance of the unique bioreactor were demonstrated by the tryptic digestion of BSA and lysozyme and the digestion time was significantly reduced to less than 5 s. The digests were identified by MALDI‐TOF MS with sequence coverages comparable to those obtained by the conventional in‐solution tryptic digestion. The present in‐needle bioreactor provides a promising platform for the high‐throughput protein identification.
Mechanism of 4‐methyl‐1,2,4‐triazol‐3‐thione reaction with formaldehyde
Authors: Wujec Monika , Paneth Piotr 
Published: April 2008

AbstractWe have recently described theoretically the mechanism of the reaction between 4‐methyl‐1,2,4‐triazol‐3‐thiol and formaldehyde that leads to the N‐substituted product, N1‐hydroxymethyl‐4‐methyl‐1,2,4‐triazol‐3‐thione. New experimental findings indicate that the thione tautomeric form in reaction with formaldehyde also yields this product. This observation could not be explained on the basis of previous calculations, which predicted that the thione tautomer undergoes nucleophilic substitution at the sulfur atom, leading to the S‐substituted product. We present theoretical explanation of the observed reactivity. We show that under experimental conditions this reaction proceeds with the intervention of the anionic form of the triazole with the Gibbs free energy of activation of only 1.8 kcal/mol. Copyright © 2008 John Wiley & Sons, Ltd.
Solid phase synthesis of novel α/β‐tetrapeptides, electrospray ionization mass spectrometric evaluation of their metal cation complexation behavior, and conformational analysis using density functional theory (DFT)
Authors: Bandala Yamir , Aviña Judit , González Tania , Rivero Ignacio A. , Juaristi Eusebio 
Published: April 2008

AbstractThirty‐four novel α/β‐tetrapeptides (1–34) have been prepared employing solid‐phase and in‐parallel synthetic protocols. α/β‐Tetrapeptides 1–34 were prepared by a combination of three α‐amino acid residues (alanine (Ala), phenylalanine (Phe), and isoleucine (Ile)) with one β‐amino acid residue (β3‐homophenylglycine). The corresponding complexes of several selected α/β‐tetrapeptides with alkali, alkaline earth, and transition metals, [tP + M+], were evaluated using ion electrospray‐ionization mass spectrometry (ESI‐MS). According to the results from analysis of mixtures, we can conclude that the position of the β‐amino acid is determinant in the affinity toward different metal cations. Computational modeling (DFT, B3LYP 6‐311++G) provided useful information regarding the most likely coordination sites of the metal ions on the receptor α/β‐tetrapeptide 12, HO2C‐α‐Phe‐α‐Phe‐α‐Ile‐β3‐hPhg‐NH2, as well as the conformational changes induced by the metal upon [tP + M+] complex formation. Copyright © 2008 John Wiley & Sons, Ltd.
Theoretical study of racemization in chiral alkenylidene truxenes
Authors: Alkorta Ibon , Blanco Fernando , Elguero José 
Published: April 2008

AbstractDFT based methods have been used to study the racemization process of chiral truxene derivatives. Four minima and the transition state connecting them have been characterized. It has been found that the energetic results for the transition states are correlated for each compound and also among the different systems considered. Thus, a unique equation has been found to fit all the values obtained. Model systems have shown that the calculated barriers are not inherent to the truxene structure. The AIM analysis has shown the presence of a large number of intramolecular closed‐shell interactions while electron density and Laplacian at the bond critical points are exponentially correlated with the interatomic distance. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of electron–phonon interaction on Fano interference in the parallel double quantum dot structure
Authors: Gong Weijiang , Zheng Yisong , Wang Jie , Lü Tianquan 
Published: April 2008

AbstractThe effect of electron–phonon interaction on the Fano lineshape in the linear conductance spectrum in the parallel double quantum dot structure is studied. The local and non‐local phonon modes are considered and the corresponding electron transport formulae are derived on an equal footing. It is found that the inelastic conductance vanishes in the zero bias and zero temperature case. The local and non‐local phonon modes influence the Fano lineshape distinctly. The non‐local phonon can change the Fano lineshape effectively, while the local phonon mainly shifts the initial Fano lineshape. These properties are still distinct for the finite temperature case when the inelastic scattering process is more complex. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Induction of G2/M arrest and apoptosis by water extract of Strychni Semen in human gastric carcinoma AGS cells
Authors: Lee Sang Man , Kwon Jae Im , Choi Yung Hyun , Eom Hyun Sup , Chi Gyoo Yong 
Published: April 2008

AbstractThe seed of Strychnos nux‐vomica (Loganiaceae) has been used in traditional Oriental medicine as a folk remedy for the treatment of cancer. However, the mechanism responsible for the anticancer effects of Strychni Semen is not clearly understood.The study tested whether and how the water extract of Strychni Semen (ESS) treatment would affect the growth of AGS human gastric carcinoma cells. ESS was found to inhibit the growth of AGS cells in a concentration‐dependent manner. Cell cycle analysis showed G2/M phase arrest and apoptosis in AGS cells following ESS treatment. ESS‐mediated G2/M arrest was found to be associated with up‐regulation of cyclin A, Cdc2, tumor suppressor p53 and cyclin dependent kinase (Cdk) inhibitor p21(WAF1/CIP1), whereas the expressions of other G2/M regulatory proteins, including cyclin B1 and Cdk2, were down‐regulated compared with the control. The induction of apoptotic cell death by ESS was associated with down‐regulation of anti‐apoptotic Bcl‐2 and up‐regulation of pro‐apoptotic Bax expression. Further results indicate that caspase‐3, caspase‐8 and caspase‐9 are all activated by ESS, together with cleavage of downstream caspase‐3 target proteins. Taken together, the results of this study suggest the involvement of multiple signaling pathways targeted by ESS in mediating G2/M cell cycle arrest and apoptosis in AGS cells, and warrant further investigation. Copyright © 2008 John Wiley & Sons, Ltd.
A combined extract of Cinnamomi Ramulus, Anemarrhenae Rhizoma and Alpiniae Officinari Rhizoma suppresses production of nitric oxide by inhibiting NF‐κB activation in RAW 264.7 cells
Authors: Jeong Mi‐Young , Lee Ji‐Suk , Lee Jae‐Dong , Kim Nam‐Jae , Kim Jin‐Woo , Lim Sabina 
Published: April 2008

AbstractAn herbal mixture prepared with Cinnamomi Ramulus, Anemarrhenae Rhizoma and Alpiniae Officinari Rhizoma (CAA) is used in oriental medicine for treating several ailments. The purpose of this study was to determine the mechanisms by which CAA elicits an antiinflammatory effect on nitric oxide (NO) production in the mouse macrophage cell line RAW 264.7 cells. The results indicated that lipopolysaccharide (LPS)‐induced NO production was inhibited by CAA in a dose‐dependent manner. Western blotting and RT‐PCR analysis demonstrated that CAA decreased LPS‐induced inducible nitric oxide synthase (iNOS) protein and gene expression in RAW 264.7 cells. Furthermore, CAA inhibited the LPS‐induced DNA binding activity of nuclear factor‐kappa B (NF‐κB) and this effect was mediated through inhibiting the degradation of inhibitory factor‐κBα (IκBα). Therefore, the results demonstrate that CAA inhibits LPS‐induced production of NO and expression of iNOS by blocking NF‐κB activation. CAA might be a potential therapeutic candidate for treating inflammatory diseases such as arthritis. Copyright © 2008 John Wiley & Sons, Ltd.
Influence of dietary composition on the carbon, nitrogen, oxygen and hydrogen stable isotope ratios of milk
Authors: Camin Federica , Perini Matteo , Colombari Gianni , Bontempo Luana , Versini Giuseppe 
Published: April 2008

AbstractThe stable isotope ratios (13C/12C, 15N/14N, 18O/16O, D/H) of animal feed and milk were investigated, considering cows stabled in two farms and fed with diets made up of different kinds of C3 plants and different amounts of maize. Maize was characterised by δ13C, δ18O and δD values significantly higher than those of the C3 plants, while, for the C3 plants, Festuca arudinacea had significantly higher content of 13C and 15N. The δ13C and δ18O values of the overall diet and the δ13C of milk casein and lipids were shown to be significantly correlated with the percentage of maize in the animal diet. On the other hand, the δ18O values of milk water and the δ18O, δD and δ15N values of casein were shown to be only slightly influenced by the amount of maize in the feed, being probably more closely correlated with the geo‐climatic and pedological characteristics of the area of origin and with the presence of fresh plant or silage in the ration. The δ13C value of casein was shown to be a suitable parameter for evaluating the amount of maize in the diet: each 10% increase in the maize content corresponded to a shift of 0.7‰ to 1.0‰ in the δ13C of casein. A threshold value of −23.5‰ for δ13C in milk casein, above which it is not possible to exclude the presence of maize in the diet, was suggested. The results obtained could be useful for determining mislabelling of dairy products declared to have been produced by pastured animals or of PDO cheeses with an established amount of maize in the diet and for verifying the unpermitted addition of exogenous components to milk. Copyright © 2008 John Wiley & Sons, Ltd.
Organic oxygen and hydrogen isotopes in a porcine controlled dietary study
Authors: Tuross Noreen , Warinner Christina , Kirsanow Karola , Kester Cynthia 
Published: April 2008

AbstractControlled feeding studies have been useful in assessing the relationship between isotope values from dietary sources and consumer tissues. We report the organic oxygen and hydrogen values of animal tissue from a porcine controlled dietary study. A complex mixture of fractionation and incorporation is revealed. In both δD and δ18O, differences in the absolute values and the amount of variation between and within consumer tissue are documented. Significant differences in δD and δ18O are observed between protein sources such as keratin and collagen. Copyright © 2008 John Wiley & Sons, Ltd.
Housing Problems and Prospects for Blacks in Houston
Authors: Bullard Robert D. 
Published: April 2008

Houston was considered the premier Sunbelt city in the 1970s. Much of the growth during this boom period was fueled by the oil industry. The city led the nation in new jobs created and housing starts. The economic growth, however, was not uniformly distributed to all segments of the population—specifically, a large segment of the black community was passed over during the city's housing boom. Many of the housing problems facing black Houstonians can be traced to the city's anti-public housing sentiment, policies that create and perpetuate racial segregation, and the dismantling of the fair housing enforcement mechanism. Housing discrimination, residential segregation, and other institutional barriers all limit the mobility options for a sizable segment of the black Houston community.
Determination of foreign materials of plant origin in cotton linters
Authors: Jurbergs K. A. , Dowling D. J. 
Published: April 2008

AbstractThe present article describes a test procedure which can be used for determination of foreign materials of plant origin in raw cotton linters. Laboratories that perform the cellulose yield test require very little additional equipment to carry out this test. A portion of the dry cellulose sample, remaining after the completion of the AOCS Official Cellulose Yield Method Bb 3舑47 is bleached, formed into a hand sheet and the total projected area of the visible dirts is determined on both sides of the hand sheet. The determination of the dirts is patterned according to principles used in Technical Association of Pulp and Paper Industries Standard Procedures T213 M‐43 and T437 M‐43.There are three main groups of foreign materials encountered: stalks, cockle burs and cotton seed hulls. The numbers and distribution of these particles vary with the general geographic locality and individual shipments of cotton linters. The test procedure described considers only those dirt particles which survive the major purification steps in the manufacturing of pulp from linters, and are undesirable from the quality point of view of the finished product. Prior to the development of the test only visual grading estimations have been used for this purpose.
Fatty acids of pimiento pepper seed oil
Authors: Marion J. E. , Dempsey A. H. 
Published: April 2008

AbstractPimiento pepper (Capsicum annum L.) seed oil was shown to contain 66舑71% linoleic acid with smaller quantities of 16 and 18 carbon saturated and monounsaturated fatty acids. Neither geographical location nor location within pimiento processing plants influenced the level or composition of the seed oil. Two varieties of bell‐type peppers were shown to have essentially the same seed oil composition as that of pimientos. Oil extracted from the fruit wall and placenta of pimientos was red and contained high levels of linolenic and small quantities of very long chain polyunsaturated fatty acids.
Genetic causes of hypercalciuric nephrolithiasis
Authors: Stechman Michael J. , Loh Nellie Y. , Thakker Rajesh V. 
Published: April 2008

AbstractRenal stone disease (nephrolithiasis) affects 3–5% of the population and is often associated with hypercalciuria. Hypercalciuric nephrolithiasis is a familial disorder in over 35% of patients and may occur as a monogenic disorder that is more likely to manifest itself in childhood. Studies of these monogenic forms of hypercalciuric nephrolithiasis in humans, e.g. Bartter syndrome, Dent’s disease, autosomal dominant hypocalcemic hypercalciuria (ADHH), hypercalciuric nephrolithiasis with hypophosphatemia, and familial hypomagnesemia with hypercalciuria have helped to identify a number of transporters, channels and receptors that are involved in regulating the renal tubular reabsorption of calcium. Thus, Bartter syndrome, an autosomal disease, is caused by mutations of the bumetanide-sensitive Na–K–Cl (NKCC2) co-transporter, the renal outer-medullary potassium (ROMK) channel, the voltage-gated chloride channel, CLC-Kb, the CLC-Kb beta subunit, barttin, or the calcium-sensing receptor (CaSR). Dent’s disease, an X-linked disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is due to mutations of the chloride/proton antiporter 5, CLC-5; ADHH is associated with activating mutations of the CaSR, which is a G-protein-coupled receptor; hypophosphatemic hypercalciuric nephrolithiasis associated with rickets is due to mutations in the type 2c sodium–phosphate co-transporter (NPT2c); and familial hypomagnesemia with hypercalciuria is due to mutations of paracellin-1, which is a member of the claudin family of membrane proteins that form the intercellular tight junction barrier in a variety of epithelia. These studies have provided valuable insights into the renal tubular pathways that regulate calcium reabsorption and predispose to hypercalciuria and nephrolithiasis.
Evaluation of the preventative effects exerted byLactobacillus fermentumin an experimental model of septic shock induced in mice
Authors: Arribas Belén , Elena Rodríguez-Cabezas Maria , Comalada Mònica , Bailón Elvira , Camuesco Desireé , Olivares Mónica , Xaus Jordi , Zarzuelo Antonio , Gálvez Julio 
Published: April 2008

The preventative effects of the probioticLactobacillus fermentumCECT5716 were evaluated in the lipopolysaccharide (LPS) model of septic shock in mice. The probiotic was administered suspended in drinking water at the final concentration of 108colony-forming units/ml for 2 weeks before the induction of an endotoxic shock by an intraperitoneal injection of LPS (400 μg/200 μl per mouse). Blood and different organs were collected after 24 h to evaluate the severity of the endotoxic shock and the preventative effects of the probiotic.L. fermentumreduced TNF-α levels in blood, which promotes the major alterations observed during septic shock, as well as the infiltration of activated neutrophils into the lungs. Furthermore, free radical overproduction and oxidative stress were associated with a significant decrease in hepatic glutathione levels in septic mice, and with an excessive NO production attributed to the induction of the inducible isoform of NO synthase (iNOS). In fact, hepatic glutathione levels were significantly increased in the group of mice receiving the probiotic, and the increased iNOS expression both in the colon and lungs was down-regulated in those mice treated withL. fermentum. Finally, pre-treatment withL. fermentummay also exert its protective action modulating the expression of different cytokines in splenocyte-derived T cells such us IL-2, IL-5, IL-6 or IL-10. In conclusion, pre-treatment withL. fermentummay exert its protective action against LPS-induced organ damage in mice by a combination of several actions including its antioxidant properties and by reduction of the synthesis of the pro-inflammatory TNF-α and IL-6.
The Dynamics of Poverty in Chile
Authors: NEILSON CHRISTOPHER , CONTRERAS DANTE , COOPER RYAN , HERMANN JORGE 
Published: April 2008

AbstractThis paper uses the 1996–2001 National Socioeconomic Survey panel database to analyse poverty dynamics in Chile, drawing a distinction between chronic and transient poverty. We found that while 20 per cent of the population was living below the official poverty line both in 1996 and 2001, only 9 per cent of the population was poor at both dates. We also found that when the poverty line was raised, the amount of households which could be considered chronically poor rose steadily, whereas the transitory component of poverty remained more or less stable. Analysis of the direct reasons for changes in household poverty status leads us to the conclusion that labour dynamics are far more relevant than demographic changes. Household heads who suffered health problems are significantly less likely to leave poverty. Household human and physical capital are also relevant, as well as the sector in which the household head works. Simulating this exercise using different poverty lines reveals that some variables are not robust to changes in the definition of poverty, while others which originally appeared to be insignificant become so for most other possible poverty lines.
Godparents and Trading Partners: Social and Economic Relations in Peruvian Amazonia
Authors: KILLICK EVAN 
Published: April 2008

AbstractThrough an ethnographic account of contemporary relations between Ashéninka men and mestizos on the Ucayali River in Eastern Peru, this article examines how individuals use specific cultural idioms in their attempts to counteract the exploitative nature of economic relations. Specifically the article considers how the institutions of ayompari trading partners and compadrazgo (godparenthood) are used by Ashéninka and mestizo individuals respectively to understand and try to control their relationships within the local economic system of habilitación. The article concludes by noting the continued importance of these individual relationships in light of recent changes to Peru's forestry laws.
Spatial transportation networks with transfer costs: asymptotic optimality of hub-and-spoke models
Authors: ALDOUS DAVID J. 
Published: April 2008

AbstractConsider networks onnvertices at average density 1 per unit area. We seek a network that minimizes total length subject to some constraint on journey times, averaged over source-destination pairs. Suppose journey times depend on both route-length and number of hops. Then for the constraint corresponding to an average of 3 hops, the length of the optimal network scales asn13/10. Alternatively, constraining the average number of hops to be 2 forces the network length to grow slightly faster than ordern3/2. Finally, if we require the network length to beO(n) then the mean number of hops grows as order log logn. Each result is an upper bound in the worst case (of vertex positions), and a lower bound under randomness or equidistribution assumptions. The upper bounds arise in simple hub and spoke models, which are therefore optimal in an order of magnitude sense.
Accurate and efficient expression evaluation and linear algebra
Authors: Demmel James , Dumitriu Ioana , Holtz Olga , Koev Plamen 
Published: April 2008

We survey and unify recent results on the existence of accurate algorithms for evaluating multivariate polynomials, and more generally for accurate numerical linear algebra with structured matrices. By ‘accurate’ we mean that the computed answer has relative error less than 1,i.e., has some correct leading digits. We also address efficiency, by which we mean algorithms that run in polynomial time in the size of the input. Our results will depend strongly on the model of arithmetic: most of our results will use the so-calledtraditional model(TM), where the computed result of op(a,b), a binary operation likea+b, is given by op(a,b) * (1+δ) where all we know is that |δ| ≤ ε ≪ 1. Here ε is a constant also known as machine epsilon.We will see a common reason for the following disparate problems to permit accurate and efficient algorithms using only the four basic arithmetic operations: finding the eigenvalues of a suitably discretized scalar elliptic PDE, finding eigenvalues of arbitrary products, inverses, or Schur complements of totally non-negative matrices (such as Cauchy and Vandermonde), and evaluating the Motzkin polynomial. Furthermore, in all these cases the high accuracy is ‘deserved’,i.e., the answer is determined much more accurately by the data than the conventional condition number would suggest.In contrast, we will see that evaluating even the simple polynomialx+y+zaccurately is impossible in the TM, using only the basic arithmetic operations. We give a set of necessary and sufficient conditions to decide whether a high accuracy algorithm exists in the TM, and describe progress toward a decision procedure that will take any problem and provide either a high-accuracy algorithm or a proof that none exists.When no accurate algorithm exists in the TM, it is natural to extend the set of available accurate operations by a library of additional operations, such asx+y+z, dot products, or indeed any enumerable set which could then be used to build further accurate algorithms. We show how our accurate algorithms and decision procedure for finding them extend to this case.Finally, we address other models of arithmetic, and the relationship between (im)possibility in the TM and (in)efficient algorithms operating on numbers represented as bit strings.