bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Association of OGG1 Ser326Cys Polymorphism and Urinary 8-OHdG Levels With Lung Cancer Susceptibility: A Hospital-Based Case-Control Study in Turkey
Authors: Karahalil Bensu , Emerce Esra , Koçer Bülent , Han Serdar , Alkiş Necati , Karakaya Ali 
Published: December 2008

The Association of OGG1 Ser326Cys Polymorphism and Urinary 8-OHdG Levels With Lung Cancer Susceptibility: A Hospital-Based Case-Control Study in TurkeyHigh incidence and poor prognosis of lung cancer make it a major health problem worldwide. Although smoking is a major cause of lung cancer, only some smokers develop lung cancer, which suggests that there is a genetic predisposition in some individuals. 8-OHG is an important oxidative base lesion and may elevate due to cancer and smoking. It is repaired by 8-hydroxyguanine DNA glycosylase 1 (OGG1), which has several polymorphisms. Although the Ser326Cys polymorphism is consistently associated with a range of cancers, findings about this polymorphism and lung cancer risk are contradictory. To date, no study has examined this association in the Turkish population. We conducted a case-control study to investigate the association between OGG1 Ser326Cys polymorphism and the risk of lung cancer using PCR-RFLP. We also evaluated gene-smoking interaction and excretion of urinary 8-OHdG. Our results suggest that the OGG1 Ser326Cys polymorphism is not a genetic risk factor for lung cancer, and that the heterozygous genotype is associated with a significantly reduced risk for lung cancer. The levels of 8-OHdG did not correlate with the polymorphism and smoking. Larger association studies are needed to validate our findings, and mechanistic studies are needed to elucidate the underlying molecular mechanisms of this association.
Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part I: Optimisation of the Synthesis Procedure of δ-Na2Si2O5 and α-Na2Si2O5
Authors: Michalik-Zym Alicja , Zimowska Małgorzata , Bahranowski Krzysztof , Serwicka Ewa 
Published: December 2008

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part I: Optimisation of the Synthesis Procedure of δ-Na2Si2O5and α-Na2Si2O5Optimization of the synthetic procedures described in literature aimed at preparing pure δ-Na2Si2O5has been carried out. The results show that a substantial shortening of the calcination time of amorphous silicate precursor is required, in order to minimize the appearance of the thermodynamically stable α-Na2Si2O5. The use of commercial water glass solution rather than freshly synthesized silica/NaOH slurry is the preferred source of the starting amorphous silicate. Optimized preparative routes for synthesis of single-phase δ-Na2Si2O5and α-Na2Si2O5have been described.
Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-Na2Si2O5 and α-Na2Si2O5
Authors: Michalik-Zym Alicja , Zimowska Małgorzata , Bielańska Elżbieta , Bahranowski Krzysztof , Serwicka Ewa 
Published: December 2008

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-Na2Si2O5and α-Na2Si2O5Reaction of δ-Na2Si2O5and α-Na2Si2O5with water at ambient conditions has been studied. The first substrate produced kanemite, the other a crystalline solid, assumed to be the layered hydrated α phase of yet unknown structure. Important differences have been observed in the kinetics of δ-Na2Si2O5and α-Na2Si2O5reactions with water, the phase transformation of the latter being distinctly slower. The observed different rates of hydration were associated with the different structural properties of the disilicates investigated. Hydrated δ-Na2Si2O5and α-Na2Si2O5possess, respectively, the platy and the needle-like morphology. Hydrated α-Na2Si2O5contains less interlayer water, which is considered the reason for basal spacing being lower than that of kanemite. The interlayer water trapped between the layers of hydrated α-Na2Si2O5is more strongly bound than that in kanemite.
Polymer‐Supported N‐Phenylsulfonyloxaziridine (Davis Reagent): A Versatile Oxidant
Authors: Gao Yongnian , Lam Yulin 
Published: December 2008

AbstractAn efficient preparation of a new recyclable polymer‐supported oxidizing agent based on N‐phenylsulfonyloxaziridine has been developed. This new polymer‐supported oxidant was shown to effect a clean and selective conversion of a range of sulfides, selenides, amines, phosphines and enolates to the corresponding sulfoxides, selenoxides, N‐oxides, phosphine oxides and α‐hydroxy carbonyl compounds. It also enabled tetrahydrobenzimidazoles to be oxidatively rearranged to spiro‐fused 5‐imidazolones. Recycling of the polymer‐supported oxidant is possible with minimal loss of activity after several reoxidations.
Catalyst‐Free Aldol Additions of 1,3‐Dicarbonyl Compounds
Authors: Rohr Kerstin , Mahrwald Rainer 
Published: December 2008

AbstractSolvent‐ and catalyst‐free aldol additions of activated aldehydes to 1,3‐dicarbonyl compounds are described. Aldol condensation was not observed under these reaction conditions. This unexpected aldol reaction could be extended successfully to a variety of acyclic and cyclic β‐dicarbonyl compounds.
Ligand Control in Enantioselective Desymmetrization of Bicyclic Hydrazines: Rhodium(I)‐Catalyzed Ring‐Opening versus Hydroarylation
Authors: Panteleev Jane , Menard Frederic , Lautens Mark 
Published: December 2008

AbstractThe efficient desymmetrization of 2,3‐bicyclic hydrazines with boronic acids through rhodium‐catalyzed ring‐opening or reductive arylation is described. Excellent levels of enantioselectivity are achieved in ring‐opening with ortho‐substituted boronic acids, using Josiphos‐type ligands. Alternatively, reductive arylation occurs selectively with electron‐poor Josiphos and Walphos ligands. A CH activation/1,4‐migration mechanism was established through deuterium transfer experiments.
Forcing a cis‐Product by Matrix Imprinting: Heck Reaction Catalyzed by Palladium Acetate Entrapped within cis‐Imprinted Sol‐Gel Derived Silicates
Authors: Tsvelikhovsky Dmitry , Pessing Dikla , Avnir David , Blum Jochanan 
Published: December 2008

AbstractWhile the Heck coupling of aryl bromides with styrenes by palladium acetate entrapped within octylated silica sol‐gel forms almost entirely trans‐stilbenes, the catalysis by the palladium compound within the cis‐pre‐imprinted support gives stilbenes that are substantially enriched by cis‐oriented isomers. Although the ceramic support is completely freed from the imprint prior to the coupling process, cis‐stilbenes are formed with similar selectivities upon recycling of the catalyst systems for at least four consecutive runs.
The Liebeskind–Srogl CC Cross‐Coupling Reaction
Authors: Prokopcová Hana , Kappe C. Oliver 
Published: December 2008

AbstractNew kid on the block: The cross‐coupling of thioorganic compounds with boronic acids under neutral conditions in the presence of catalytic palladium(0) and a stoichiometric amount of a copper(I) oxygenate has emerged as a very useful method for the construction of CC bonds (see scheme). This intriguing and mechanistically unprecedented base‐free coupling has distinct advantages, in particular when traditional Pd0‐catalyzed cross‐coupling is not possible.magnified imageAlthough a plethora of highly selective and reliable methods for the construction of CC bonds are known to organic chemists, there is growing interest in the development of new protocols that offer different or orthogonal reactivity to that of existing methods. In 2000, Liebeskind and Srogl described a mechanistically unprecedented transition‐metal‐catalyzed cross‐coupling of thioesters with boronic acids to produce ketones under neutral conditions. This desulfitative cross‐coupling process is catalytic in palladium(0), stoichiometric in copper(I), and applicable to a range of organosulfur derivatives and nucleophilic organometallic reagents. In this Minireview, we highlight recent applications of this intriguing cross‐coupling reaction in modern organic synthesis, with an emphasis on cases in which traditional methods for CC bond formation have failed.
Adaptive feedback control in complex delayed dynamical networks
Authors: Wang L. , Dai H. P. , Sun Y. X. 
Published: December 2008

AbstractRecently, complex networks have attracted a great deal of attention in various fields of nature and society. In this paper, an adaptive feedback control scheme is introduced to synchronize a general complex dynamical network with time‐varying delay. By construction of Lyapunov functional, we deduce that global synchronization of the network model can be guaranteed by the proposed control scheme. Numerical simulation illustrated by a three‐node network shows that the adaptive feedback control scheme can ensure adaptive synchronization of the controlled network even without the information of network topological structure and coupling strength. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.
Diphenylprolinol Silyl Ether as a Catalyst in an Enantioselective, Catalytic Michael Reaction for the Formation of α,α‐Disubstituted α‐Amino Acid Derivatives
Authors: Hayashi Yujiro , Obi Kazuki , Ohta Yusuke , Okamura Daichi , Ishikawa Hayato 
Published: December 2008

AbstractDirect and enantioselective: Diphenylprolinol silyl ether was found to catalyze the direct, asymmetric Michael reaction of 4‐substituted 2‐aryl‐2‐oxazoline‐5‐one and α,β‐unsaturated aldehydes, affording the chiral α,α‐disubstituted α‐amino acid derivatives with excellent enantioselectivity.magnified image
Population pharmacokinetics of valproate in Mexican children with epilepsy
Authors: Correa Tania , Rodríguez Ildefonso , Romano Silvia 
Published: December 2008

AbstractBackground. The aim of this study was to determine the factors that influence valproate clearance (CL) in Mexican epileptic pediatric patients using a mixed‐effect model and sparse data of serum concentrations of valproic acid (VPA) collected during routine clinical care of patients.Methods. The number of patients included in the study was 110. The population CL was calculated by using the NONMEM program. The following covariates were tested by their influence on CL: total body weight (TBW), height, age, body surface area, daily dose (DD), sex of the patient and comedication with phenobarbital (PB) or carbamazepine.Results. The final regression model for valproic CL found best to describe the data was: CL/F=(0.0466+0.00363 TBW+0.000282 DD) * (1+0.236 PB). This model allows a reduction of 50% of the interindividual variability and of 31% of the residual variability described by the basic model that does not include covariables.Conclusions. Total body weight, daily dose of valproate and concomitant therapy with PB are factors that significantly influence VPA kinetic disposition and they should be considered in programming dosage regimens for this antiepileptic drug in the pediatric population. The validation of the model supports its acceptability for clinical purposes. Copyright © 2008 John Wiley & Sons, Ltd.
Celebrating Fifty Years of the Biometrical Journal
Authors: Victor N. , Läuter J. , Ihm P. , Dietz K. 
Published: December 2008

AbstractThe publication of Volume 50 of the Biometrical Journal (formerly Biometrische Zeitschrift) in 2008 provides the perfect opportunity to describe the history of the present journal. We report on the long period of preparation for the journal within the German Region (DR) of the International Biometric Society (IBS). A special paragraph is dedicated to the first ten volumes. We emphasize the role of the journal as a bond between German biometricians on both sides of the border between the two German nations and IBS regions at that time. Furthermore, we report on the development of its thematic spectrum and impact factors and provide citation frequencies. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The Petersen–Lincoln Estimator and its Extension to Estimate the Size of a Shared Population
Authors: Chao Anne , Pan H.‐Y. , Chiang Shu‐Chuan 
Published: December 2008

AbstractThe Petersen–Lincoln estimator has been used to estimate the size of a population in a single mark release experiment. However, the estimator is not valid when the capture sample and recapture sample are not independent. We provide an intuitive interpretation for “independence” between samples based on 2 × 2 categorical data formed by capture/non‐capture in each of the two samples. From the interpretation, we review a general measure of “dependence” and quantify the correlation bias of the Petersen–Lincoln estimator when two types of dependences (local list dependence and heterogeneity of capture probability) exist. An important implication in the census undercount problem is that instead of using a post enumeration sample to assess the undercount of a census, one should conduct a prior enumeration sample to avoid correlation bias. We extend the Petersen–Lincoln method to the case of two populations. This new estimator of the size of the shared population is proposed and its variance is derived. We discuss a special case where the correlation bias of the proposed estimator due to dependence between samples vanishes. The proposed method is applied to a study of the relapse rate of illicit drug use in Taiwan. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Estimating Completeness in Cancer Registries – Comparing Capture‐Recapture Methods in a Simulation Study
Authors: Schmidtmann Irene 
Published: December 2008

AbstractCompleteness of registration is one of the quality indicators usually reported by cancer registries. This allows researchers to assess how useful and representative the data is. Several methods have been suggested to estimate completeness. In this paper a multi‐state model for the process of cancer diagnosis and treatment is presented. In principle, every contact with a doctor during diagnosis, treatment, and aftercare can give rise to a cancer registry notification with a certain probability. Therefore the states included in the model are “incident tumour” and “death” but also contacts with doctors such as consultation of a general practitioner or specialised doctor, diagnostic procedures, therapeutic interventions, and aftercare. In this model transitions between states and possible notifications to a cancer registry after entering a state are simulated. Transition intensities are derived and used in simulation. Several capture‐recapture methods have been applied to the simulated data. Simulated “true” numbers of new cases and simulated numbers of registrations are both available. This allows to assess the validity of the completeness estimates and to compare the relative merits of the methods. In the scenarios investigated here, all capture‐recapture estimators tended to underestimate completeness. While a modified DCN method and one type of log‐linear model yielded quite reasonable estimates other methods exhibited large variability or grossly underestimated completeness. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hybridization of short complementary PNAs to G‐quadruplex forming oligonucleotides: An electrospray mass spectrometry study
Authors: Amato Jussara , Oliviero Giorgia , De Pauw Edwin , Gabelica Valérie 
Published: December 2008

AbstractWe investigated the interaction of the short peptide nucleic acid (PNA) strand [acccca]‐PNA with oligodeoxynucleotides containing one, two, or four tracts of TGGGGT units. Electrospray ionization mass spectrometry allowed exploring the wide variety of complex stoichiometries that were found to coexist in solution. In water, the PNA strand forms short heteroduplexes with the complementary DNA sequences, but higher‐order structures are also found, with PNA2n·DNAn triplex units, culminating in precipitation at very low ionic strength. In the presence of ammonium acetate, there is a competition between PNA·DNA heteroduplex formation and DNA G‐quadruplex formation. Heteroduplex formation is favored when the PNA + DNA mixture in ammonium acetate is heated and cooled at room temperature, but not if the PNA is added at room temperature to the preformed G‐quadruplex. We also found that the short [acccca]‐PNA strand binds to G‐quadruplexes. © 2008 Wiley Periodicals, Inc. Biopolymers 91: 244–255, 2009.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
An Unusual Stable Mononuclear MnIII Bis‐terpyridine Complex Exhibiting Jahn–Teller Compression: Electrochemical Synthesis, Physical Characterisation and Theoretical Study
Authors: Romain Sophie , Duboc Carole , Neese Frank , Rivière Eric , Hanton Lyall R. , Blackman Allan G. , Philouze Christian , Leprêtre Jean‐Claude , Deronzier Alain , Collomb Marie‐Noëlle 
Published: December 2008

AbstractThe mononuclear manganese bis‐terpyridine complex [Mn(tolyl‐terpy)2](X)3 (1(X)3; X=BF4, ClO4, PF6; tolyl‐terpy=4′‐(4‐methylphenyl)‐2,2′:6′,2“‐terpyridine), containing Mn in the unusual +III oxidation state, has been isolated and characterised. The 13+ ion is a rare example of a mononuclear MnIII complex stabilised solely by neutral N ligands. Complex 13+ is obtained by electrochemical oxidation of the corresponding MnII compound 12+ in anhydrous acetonitrile. Under these conditions the cyclic voltammogram of 12+ exhibits not only the well‐known MnII/MnIII oxidation at E1/2=+0.91 V versus Ag/Ag+ (+1.21 V vs. SCE) but also a second metal‐based oxidation process corresponding to MnIII/MnIV at E1/2=+1.63 V (+1.93 V vs. SCE). Single crystals of 1(PF6)3⋅2 CH3CN were obtained by an electrocrystallisation procedure. X‐ray analysis unambiguously revealed its tetragonally compressed octahedral geometry and high‐spin character. The electronic properties of 13+ were investigated in detail by magnetic measurements and theoretical calculations, from which a D value of +4.82 cm−1 was precisely determined. Density functional and complete active space self consistent field ab initio calculations both correctly predict a positive sign of D, in agreement with the compressed tetragonal distortion observed in the X‐ray structure of 1(PF6)3⋅2 CH3CN. The different contributions to D were calculated, and the results show that 1) the spin–orbit coupling part (+2.593 cm−1) is predominant compared to the spin–spin interaction (+1.075 cm−1) and 2) the excited triplet states make the dominant contribution to the total D value.
Effects on the Reactivity by Changing the Electrophilic Center from CO to CS: Contrasting Reactivity of Hydroxide, p‐Chlorophenoxide, and Butan‐2,3‐dione Monoximate in DMSO/H2O Mixtures
Authors: Um Ik‐Hwan , Han Jeong‐Yoon , Buncel Erwin 
Published: December 2008

AbstractSecond‐order rate constants have been measured spectrophotometrically for the reactions of O‐p‐nitrophenyl thionobenzoate (1, PNPTB) with HO−, butan‐2,3‐dione monoximate (Ox−, α‐nucleophile), and p‐chlorophenoxide (p‐ClPhO−, normal nucleophile) in DMSO/H2O of varying mixtures at (25.0±0.1) °C. Reactivity of these nucleophiles significantly increases with increasing DMSO content. HO− is less reactive than p‐ClPhO− toward 1 up to 70 mol % DMSO although HO− is over six pKa units more basic in these media. Ox− is more reactive than p‐ClPhO− in all media studied, indicating that the α‐effect is in effect. The magnitude of the α‐effect (i.e., k/kp) increases with the DMSO content up to 50 mol % DMSO and decreases beyond that point. However, the dependency of the α‐effect profile on the solvent for reactions of 1 contrasts to that reported previously for the corresponding reactions of p‐nitrophenyl benzoate (2, PNPB); reactions of 1 result in much smaller α‐effects than those of 2. Breakdown of the α‐effect into ground‐state (GS) and transition‐state (TS) effects shows that the GS effect is not responsible for the α‐effect across the solvent mixtures. The role of the solvent has been discussed on the basis of the bell‐shaped α‐effect profiles found in the current study as well as in our previous studies, that is, a GS effect in the H2O‐rich region through H‐bonding interactions and a TS effect in the DMSO‐rich media through mutual polarizability interactions.
Telencephalic morphogenesis during the process of neurulation: An experimental study using quail–chick chimeras
Authors: Pombero Ana , Martinez Salvador 
Published: December 2008

AbstractAfter gastrulation, during the process of neurulation, the anterior neural region undergoes important morphological transformations. The almost flat epithelium of the rostral neural plate becomes transformed into a spherical region, the prosencephalic vesicle, in the neural tube. Later in development, two bilateral areas (the optic and telencephalic vesicles) progressively protrude from the prosencephalon, generating the eyes and the cerebral hemispheres, respectively. Although the principal processes of neurulation have been well characterized, the growth patterns and evolution of topological relations between internal prosencephalic regions have not been experimentally analyzed. In order to better characterize morphogenetic transformations of the prosencephalon, we have realized and comparatively analyzed neuroepithelial fate maps before and after neurulation using quail/chick chimerical experiments. Since we have previously reported the fate map of the prosencephalon at the neural plate stage, in the present work we report the corresponding fate map at the neural tube stage. Comparative analysis of the two maps has allowed us to descriptively characterize the morphogenetic transformations of the alar prosencephalic regions during neurulation and to establish the topologic evolution of the principal areas of the vertebrate telencephalon. J. Comp. Neurol. 512:784–797, 2009. © 2008 Wiley‐Liss, Inc.