bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tolerance and reactivity of NK cells: Two sides of the same coin?
Authors: Held Werner 
Published: October 2008

AbstractNK cells can kill transformed, infected and stressed cells while most normal cells are spared. NK cells are activated by various endogenous self‐ligands, some of which are actually expressed by normal cells. Thus, NK cells are inherently self‐reactive and consequently, potentially auto‐aggressive. How these cells are prevented from attacking normal cells while ensuring reactivity to diseased cells is a major unresolved question for NK‐cell biologists.
Beyond licensing and disarming: A quantitative view on NK‐cell education
Authors: Brodin Petter , Höglund Petter 
Published: October 2008

AbstractIn this article, we will move beyond the current controversy of different models for NK‐cell education and instead discuss the properties characterizing MHC class I‐guided functional development of NK cells. We will argue that this development, which represents the endpoint of NK‐cell education, is a quantitative and dynamic, and perhaps even reversible, process.
Aluminium Complexes of a Phenoxyimine Ligand with a Pendant Imidazolium Moiety: Synthesis, Characterisation and Evidence for Hydrogen Bonding in Solution
Authors: Milione Stefano , Grisi Fabia , Centore Roberto , Tuzi Angela 
Published: October 2008

AbstractNovel alkylaluminium complexes (phim)AlMe2 (1) and(phimid)AlR2+Br– [R = Me (2), R = iBu (3)] bearing the Schiff base ligands 3,5‐tBu2‐2‐(OH)C6H2CH=NiPr (phim‐H) and3,5‐tBu2‐2‐(OH)C6H2CH=NCH2CH2[CH(NCHCHNiPr)]Br(phimid‐H·Br) have been prepared and fully characterised. Complexes 1–3 each have a tetrahedral structure, with the aluminium atom surrounded by the oxygen and nitrogen atoms of the chelating ligand and two alkyl groups. The structures of phimid‐H·Br and of complex 1 have been determined by X‐ray diffraction studies. Investigation of the solution structures of 1–3 by 1H NMR spectroscopy revealed that the coordinated phimid ligand is involved in hydrogen bonding with bromide anion. Treatment of 1 with B(C6F5)3 led smoothly to (phim)Al(C6F5)Me (4) by transfer of a C6F5 group from MeB(C6F5)3– to the initially formed coordinatively unsaturated cationic intermediate. In contrast, treatment of 2 with one equiv. of B(C6F5)3 afforded the cationic monomethyl species (phimid)AlMeBr+ MeB(C6F5)3– (5), stabilised by the coordination of the bromide anion acting as a Lewis base.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
On the Effect of Coordination and Protonation Preferences in the Amphiphilic Behavior of Metallosurfactants with Asymmetric Headgroups
Authors: Lesh Frank D. , Hindo Sarmad Sahiel , Heeg Mary Jane , Allard Marco M. , Jain Prateek , Peng Bo , Hryhorczuk Lew , Verani Cláudio N. 
Published: October 2008

AbstractThe metallosurfactants [NiII(LtBuODA)(OAc)] (1), [NiII(LtBuODA)2](2), [CuII(HLtBuODA)(LtBuODA)]ClO4·CH3OH (3), and [ZnII(HLtBuODA)2](ClO4)2 (4) {where HLtBuODA = 2,4‐di‐tert‐butyl‐6‐[(octadecyl(pyridin‐2‐ylmethyl)amino)methyl]phenol}were synthesized and characterized in an attempt to establish how coordination modes and protonation preferences relate to amphiphilic behavior. The archetypical compounds [NiII(LtBuI)(OAc)]·CH3OH (5), [NiII(LA)2]·CH3OH·H2O (6), [NiII(LtBuA)2]·2CH3OH (7), [CuII(HLtBuA)(LtBuA)]ClO4 (8), and [ZnII(HLtBuA)(LtBuA)]ClO4 (9) were synthesized to model the stoichiometric, coordination, and protonation chemistry in the waxy metallosurfactants 1–4. Detailed data analysis and comparison between 1–4 and 5–9 involved mass spectrometric and spectroscopic methods along with crystallographic determination of 5 (P21/c), 6 (P$\bar {1}$), 7 (P21/c), 8′ (the analogue of 8 with tetraphenylborate counterions, P21/c), and 9 (P$\bar {1}$). DFT calculations were used to identify the frontier orbitals, polarizability, and dipole moments. Species 1–4 had their compression isotherms measured and monitored by means of Brewster angle miscroscopy. The nickel‐containing 1 is square planar, while 2 has a neutral octahedral core with two deprotonated ligands. The five‐coordinate copper‐containing 3 has a monocationic core associated with one protonated ligand, whereas the dicationic zinc‐containing 4 has a four‐coordinate core with protonated ligands. It was observed that Langmuir films of 1 display approximately half of the average molecular area observed for 2–4 and that the flexibility and coordination number of the cores foster distinctive collapse mechanisms. Therefore, careful choice of the metal ion leads to control of surfactant‐to‐metal ratio, selection of coordination modes and structural properties, and the understanding of the protonation preferences of the ligands. This information will play an important role in the development of metal‐containing responsive films. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
A Combined NMR, Computational, and HPLC Study of the Inclusion of Aromatic and Fluoroaromatic Compounds in Cyclodextrins as a Model for Studying Carbohydrate–Aromatic Interactions
Authors: Ribeiro Joao P. , Bacchi Sergio , Dell'Anna Gianmaria , Morando Maria , Cañada F. Javier , Cozzi Franco , Jiménez‐Barbero Jesús 
Published: October 2008

AbstractA combined NMR, computational, and HPLC study of the inclusion of aromatic and fluoroaromatic compounds in cyclodextrins has been carried out with the aim of studying this process as a model for carbohydrate···aromatic interactions. NMR experiments showed that although β‐CD formed an inclusion complex with benzene, no stable inclusion adduct was formed with hexafluorobenzene. MM3* calculations confirmed these data and, when extended to naphthalene, anthracene, phenanthrene, and their partially and fully fluorinated analogues, showed that β‐CD formed inclusion adducts only with the hydrocarbons, whereas the partially fluorinated derivatives were shown to enter the cavity only with their non‐fluorinated part, and the perfluoro compounds were not included. HPLC experiments, carried out by eluting these compounds through CD‐modified HPLC columns, also confirmed these results, at least with the mono‐ and bicyclic arenes. Indeed, the elution of these derivatives showed that the efficiency of the inclusion, as determined by comparing HPLC retention times, decreased on passing from hydrocarbons to partially fluorinated compounds, and reached a minimum with perfluorinated derivatives. In contrast with this general trend, 1,2,3,4‐tetrafluoroanthracene had longer retentions times on β‐ and γ‐CD‐modified HPLC columns than anthracene, possibly for solubility reasons. As a whole, these results were interpreted in terms of carbohydrate···aromatic interactions between the C5–H5 bonds on the hydrophobic faces of the sugars and the π electrons of the aromatic partner. The interactions seem to have an important dispersive component.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Convenient Microwave‐Assisted Synthesis of 5‐Functionalized 1,2,4‐Triazolium Ylides Starting from N′,N′‐Disubstituted Carbohydrazonamides
Authors: Khankischpur Mehdi , Kurz Thomas 
Published: October 2008

Abstract5‐Functionalized 1,2,4‐triazolium ylides have been prepared in good yields and in very short reaction times by reacting N′,N′‐disubstituted carbohydrazonamides with 1,1′‐carbonylbis(1,2,4‐triazole), 1,1′‐thiocarbonyldiimidazole or diphenyl N‐cyanimidocarbonate under microwave irradiation. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)
Optimization of hydrophobic interaction chromatography using a mathematical model of elution curves of a protein mixture
Authors: Lienqueo María Elena , Shene Carolina , Asenjo Juan 
Published: October 2008

AbstractThis paper describes a methodology for optimizing performance of hydrophobic interaction chromatography (HIC) for protein mixtures in which Rate Model simulations and evaluation of cost function are used. The system under study was HIC of a two‐protein mixture (α‐chymotrypsin and α‐amylase), carried out with different conditions (gradient steepness, salt, concentration, volume of sample, pH, type of matrix, and flow rates). Parameters in the rate model were obtained from different sources. Mass transfer parameters (Reynolds, Peclet, and Biot numbers) were calculated using empirical correlations. Under the experimental conditions Re number was small (0.23) and axial dispersion negligible (PeL > 300). Mass transfer was controlled by intraparticle diffusion (Bi > 50). The model assumes that equilibrium constant (b) in the Langmuir isotherm was salt concentration (I) dependent [b(I)]. Parameters in the relationship for b(I) were estimated from experimental single protein elution curves and used to simulate protein mixtures. Rate model simulations showed that if protein sample load to the column was below 1 mg, displacement effects were negligible; in other cases protein interactions would limit the proposed mathematical description of HIC. The calibrated Rate Model successfully predicted elution curves of the protein mixture with deviations lower than 6 × 10−4 absorbance units. The model was also able to predict that the Butyl Sepharose—NaCl 4 M system allowed to obtain the highest resolution (>1) for the two‐protein mixture evaluated. The cost function built for optimizing the performance of HIC considers yield, purity, concentration, and the time needed to accomplish the separation. This function contains two types of parameters that have to be determined. The ones dependent on the HIC system and process conditions were obtained from simulations of elution curves of the two‐protein mixture, by the calibrated Rate Model. The other parameters are dependent on characteristic and quality of the protein product; these were assumed for illustration purpose. Minimization of the cost function allows determination of flow rate, gradient steepness, and the fraction of eluted peak that has to be collected. Novelty of the present work is in showing how parameters in the fundamentally based Rate Model for HIC can be calibrated and how simulations can be used for the optimization of process conditions for the separation of a protein mixture. Copyright © 2008 John Wiley & Sons, Ltd.
Assessment of grassland degradation in Guinan county, Qinghai Province, China, in the past 30 years
Authors: FENG Y. , LU Q. , TOKOLA T. , LIU H. , WANG X. 
Published: October 2008

AbstractIn this study, the quantity, quality and spatial changes of grassland in Guinan County, Qinghai Province, China, were assessed by means of interpreting remote sensing satellite imagery during four key periods (1976, 1996, 2001 and 2006) as well as by applying various methods of analysis such as a transition matrix, fractal dimension, dynamic degree modelling and a spatial model of land use change. The assessment results were summarized from three positions. First, grassland area decreased and grassland quality degraded in the past 30 years. The decreased rate of area and the degraded degree of quality were significantly different during different time periods. Both the decline in grassland area and the degradation in grassland quality were determined to be most severe from 1976 to 1996 (especially for high density grassland) and moderate from 1996 to 2001 and from 2001 to 2006. Second, the grassland centre of gravity trended to move along a general southeastern direction; however, the direction of movement of grassland centre of gravity displayed multidirectional and irregular tendencies during different time periods. The primary reason that caused this situation was that the cultivation and protection of grasslands occurred during successive turns. Third, the change observed in grassland behaviour was shaped by a range of factors including natural forces as well as human‐induced disturbances. The dominant factor was primarily human activity. The transition matrix method, the fractal dimension method and the spatial model of land use change method showed similar results. Copyright © 2008 John Wiley & Sons, Ltd.
Controlled Grafting‐From of Polystyrene on Polybutadiene: Mechanism and Spectroscopic Evidence of the Functionalization of Polybutadiene with 4‐Oxo‐TEMPO
Authors: Bonilla‐Cruz José , Saldívar‐Guerra Enrique , Torres‐Lubián José Román , Guerrero‐Santos Ramiro , López‐Carpy Bruno , Luna‐Bárcenas Gabriel 
Published: October 2008

AbstractPolybutadienes functionalized with nitroxide (multifunctional macroalkoxyamines) were synthesized by heating PB in the presence of a nitroxide radical (N) and a radical initiator (I). Another functional PB was prepared by using only nitroxide. These functionalized polymers were characterized by FT‐IR, GPC, and NMR and as a result it was possible to elucidate the resulting structure of the macroalkoxyamines, to propose likely functionalization mechanisms, and to estimate functionalization characteristics. One of these polymers was heated in the presence of styrene to obtain PB grafted with polystyrene, which was characterized in detail in order to investigate its structure and level of grafting control.magnified image
On the formation and persistence of superfog in woodland smoke
Authors: Achtemeier Gary L. 
Published: October 2008

AbstractDense fogs, comparable to historical fogs in England, have been implicated in numerous roadway accidents in the southern United States. Many of the fogs have occurred in association with prescribed burning. Direct measurements of superfog (fog reducing visibility to less than 3 m) were taken during burning of forest litter on 22 March 2003. Visibility was measured at 0.1 m implying an extinction coefficient of 39 120 km−1. The number of condensation nuclei required for fog to produce the observed visibility was about 1% of the number of particles released in wood smoke as reported in the literature. A recursive non‐gradient mixing model shows (1) maximum excess liquid water (LWC) released was approximately 7.0 g kg−1, 23 times the LWC in natural fog, (2) superfog can form at the site of combustion then continue to form as it drifts downwind, and (3) superfog can modify air mass stability near the ground and persist for hours until dispersed by changing wind conditions or by solar heating after sunrise. Published in 2008 by John Wiley & Sons Ltd.
Thioredoxin system inhibitors as mediators of apoptosis for cancer therapy
Authors: Tonissen Kathryn F. , Di Trapani Giovanna 
Published: October 2008

AbstractThe thioredoxin (Trx) system is a major antioxidant system integral to maintaining the intracellular redox state. It contains Trx, a redox active protein, which regulates the activity of various enzymes including those that function to counteract oxidative stress within the cell. Trx can also scavenge reactive oxygen species (ROS) and directly inhibits proapoptotic proteins such as apoptosis signal‐regulating kinase 1 (ASK1). The oxidized form of Trx is reduced by thioredoxin reductase (TrxR). The cytoplasm and mitochondria contain equivalent Trx systems and inhibition of either system can lead to activation of apoptotic signaling pathways. There are a number of inhibitors with chemotherapy applications that target either Trx or TrxR to induce apoptosis in cancer cells. Suberoylanilide hydroxamic acid (SAHA) is effective against many cancer cells and functions by up‐regulating an endogenous inhibitor of Trx. Other compounds target the selenocysteine‐containing active site of TrxR. These include gold compounds, platinum compounds, arsenic trioxide, motexafin gadolinium, nitrous compounds, and various flavonoids. Inhibition of TrxR leads to an accumulation of oxidized Trx resulting in cellular conditions that promote apoptosis. In addition, some compounds also convert TrxR to a ROS generating enzyme. The role of Trx system inhibitors in cancer therapy is discussed in this review.
Theoretical estimation of the electron affinity of enolate radicals
Authors: González‐Rivas Nelly , Cedillo Andrés 
Published: October 2008

AbstractThe electron affinity of some enolate radicals coming from methyl substituted five‐ and six‐member carbon rings is estimated by the use of the density functional theory model B3LYP/6‐311++g(3df,3pd). The computed electron affinities show an excellent agreement with recent gas phase experimental results (Walthall et al., J Phys Chem A, 2005, 109, 8785). The comparison shows differences around 1 kcal/mol for most of the compounds, except for four substituted compounds whose methyl group is neighbor to the double bond, in this case the variation increases up to 3 kcal/mol. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009
Diamide derivatives as photostabilizers for plasticized poly(vinyl chloride)
Authors: Rabie S.T. , Khalil A.M. , Nada A.A. 
Published: October 2008

AbstractSome diamide derivatives have been prepared, characterized, and investigated as photostabilizers for plasticized poly(vinyl chloride) (PVC), containing dioctyl phthalate and dibutyl phthalate in a concentration of 30% by weight of the polymer. The stabilizing efficiency of the prepared diamides was evaluated by determining the weight loss percentage that resulted from HCl evolution during the photodegradation process. Moreover, the efficiency was evaluated by determining the amount of gel formed as well as the intrinsic viscosity of the soluble fractions of the photodegraded polymer. The extent of discoloration of the photodegraded stabilized and plasticized PVC was also investigated. The stabilization mechanism and the effect of plasticizers on the photostability of PVC are discussed. J. Vinyl Addit. Technol., 2008. © 2008 Society of Plastics Engineers
Are Patient Rights to Information and Self‐Determination in Diagnostic Genetic Testing Upheld? A Comparison Of Patients’ and Providers’ Perceptions
Authors: Nyrhinen Tarja , Hietala Marja , Puukka Pauli , Leino‐Kilpi Helena 
Published: October 2008

AbstractThis study assessed how the patient's right to receive information and the right to self‐determination were followed during diagnostic testing, according to the perceptions of patients and parents of tested children (group 1, n = 106) and healthcare personnel (group 2, n = 162). Data were collected in three Finnish university hospitals using a questionnaire. Results revealed one between group difference: patients/parents agreed more strongly than did personnel that self‐determination was followed before testing. Within groups included: patients/parents had stronger agreement that self‐determination was followed before testing than after testing; personnel had stronger agreement about information received after testing than before testing, and they had weaker agreement about how well self‐determination was followed before testing than after testing. Received information was experienced as similar both before and after testing and by patients/parents and by personnel. Providing adequate time to consider whether or not to be tested and giving more support to patients after testing would promote the rights of patients. Furthermore, assessment of personnel characteristics is needed to determine, for example, the kinds of value conflicts that exist between personnel's own values and patients’ values.
Life Trajectories, Genetic Testing, and Risk Reduction Decisions in 18–39 Year Old Women at Risk for Hereditary Breast and Ovarian Cancer
Authors: Hamilton Rebekah , Williams Janet K. , Bowers Barbara J. , Calzone Kathleen 
Published: October 2008

AbstractThis qualitative study identified four life trajectories that influenced the decision in young women to have genetic testing for mutations in BRCA1/2 and subsequent risk reduction decisions after receiving a positive mutation result. Fifty nine women between the ages of 18–39 years were interviewed in this grounded theory study, 44 of those tested were found to have a mutation in either BRCA1 or BRCA2. Of those with a mutation, 23 had no history of cancer and 21 had a breast cancer diagnosis. Analysis of the 44 participants tested found that risk reducing decisions were related to the life trajectories that preceded genetic testing. These life trajectories included: 1) Long‐standing awareness of breast cancer in the family, 2) Loss of one's mother to breast cancer at a young age, 3) Expression of concern by a health care provider, and 4) Personal diagnosis of breast cancer. Understanding possible influences behind decision making for genetic testing and risk reduction in young women may assist health care providers in offering age appropriate guidance and support.
Cutaneous afferent C‐fibers regenerating along the distal nerve stump after crush lesion show two types of cold sensitivity
Authors: Grossmann Lydia , Gorodetskaya Natalia , Teliban Alina , Baron Ralf , Jänig Wilfrid 
Published: October 2008

ABSTRACTCutaneous C‐fiber afferents show two distinct types of cold sensitivity corresponding to non‐noxious and noxious cold sensations. Here, responses to cold stimulation of afferent fibers regenerating in the rat sural nerve were studied in vivo 7–14 days after nerve crush and compared with responses to mechanical and heat stimulation. The physiological stimuli were applied to the sural nerve at or distal to the lesion site. Ectopic activity was evoked in 43% of 98 A‐fibers (all mechanosensitive; a few additionally weakly thermosensitive). Ectopic activity was evoked in 127 (49.2%) of 258 electrically identified C‐fibers by the physiological stimuli. Eight C‐fibers were spontaneously active only. Of the 127 C‐fibers, 46% had one of two distinct response patterns to cooling: (1) type 1 cold‐sensitive C‐fibers (n=29) had a high rate of activity at 28°C on the nerve surface and showed graded responses to cooling with maximal discharge rates of 11.5±1.1imp/s. This activity was completely inhibited by heating, while 12/29 fibers were also excited at high threshold (median 48°C) by heating. Only one type 1 cold‐sensitive C‐fiber was mechanosensitive. (2) Type 2 cold‐sensitive C‐fibers (n=29) were silent or showed a low rate of activity at 28°C, had a high threshold (median 5°C) and low maximal discharge rates (2.4±0.4imp/s) to cooling. They were also heat‐sensitive (n=25) and/or mechanosensitive (n=20). These C‐fibers were, apart from their cold sensitivity, functionally indistinguishable from C‐fibers with mechano‐ and/or heat sensitivity only. Thus regenerating cutaneous C‐fibers show two types of cold sensitivity similar to those observed in intact skin: fibers of one group are predominantly sensitive to cooling, whereas the others are polymodal.
ON INFINITESIMAL TEICHMÜLLER SPACE
Authors: JINHUA FAN , JIXIU CHEN 
Published: October 2008

AbstractMuch research has been done on the geometry of Teichmüller space and Hamilton sequences of extremal Beltrami differentials. This paper discusses some problems concerning infinitesimal Teichmüller geodesic discs and Hamilton sequences of extremal Beltrami differentials in the tangent space of an infinite-dimensional Teichmüller space.
OPERATOR KERNELS FOR IRREDUCIBLE REPRESENTATIONS OF EXPONENTIAL LIE GROUPS
Authors: POGUNTKE DETLEV 
Published: October 2008

AbstractA nine-dimensional exponential Lie group G and a linear form ℓ on the Lie algebra of G are presented such that for all Pukanszky polarizations 𝔭 at ℓ the canonically associated unitary representation ρ=ρ(ℓ,𝔭) of G has the property that ρ(ℒ1(G)) does not contain any nonzero operator given by a compactly supported kernel function. This example shows that one of Leptin’s results is wrong, and it cannot be repaired.
ON A RECENT GENERALIZATION OF SEMIPERFECT RINGS
Authors: BÜYÜKAŞIK ENGIN , LOMP CHRISTIAN 
Published: October 2008

AbstractIn a recent paper by Wang and Ding, it was stated that any ring which is generalized supplemented as a left module over itself is semiperfect. The purpose of this note is to show that Wang and Ding’s claim is not true and that the class of generalized supplemented rings lies properly between the classes of semilocal and semiperfect rings. Moreover, we propose a corrected version of the theorem by introducing a wider notion of ‘local’ for submodules.