bluuebunny/crossref_metadata_2025 huggingface dataset:
Procedures for and Possible Mechanisms of Pd‐Catalyzed Allylations of Primary and Secondary Amines with Allylic Alcohols
Authors: Muzart Jacques
Published: May 2007

This review describes the different Pd‐catalyzed methods that afford allylic amines from intermolecular reactions between allylic alcohols and amines and, with personal comments, the mechanisms that have been proposed. Allylic amines are an important class of compounds, while a wide structural variety of allylic alcohols are commercially available and are abundant in nature. The advantages of the use of allylic alcohols over that of their derivatives such as allylic esters or carbonates are the high atom efficiency and the formation only of water as the by‐product. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
First Chemical Synthesis, Aggregation Behavior and Cholesterol Solubilization Properties of Pythocholic Acid and 16α‐Hydroxycholic Acid
Authors: Nonappa  , Maitra Uday
Published: May 2007

The first chemical synthesis of pythocholic acid, a major component of python's bile, and 3α,7α,12α,16α‐tetrahydroxy‐5β‐cholan‐24‐oic acid (16α‐hydroxycholic acid), a minor component in Shoebill stork's bile, was achieved starting from readily available cholic acid in overall yields of 5 % and 5.5 %, respectively, through a common intermediate. A biomimetic template‐directed remote functionalization strategy was utilized to selectively functionalize C‐16 of the steroid skeleton. This synthesis involves a series of regio and chemoselective transformations. Pythocholic acid showed unusually low critical micellar concentration (CMC) with high cholesterol solubilization ability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)
Majority versus minority influence: the role of message processing in determining resistance to counter‐persuasion
Authors: Martin Robin , Hewstone Miles , Martin Pearl Y.
Published: May 2007

Two experiments examined the extent to which attitudes changed following majority and minority influence are resistant to counter‐persuasion. In both experiments participants' attitudes were measured after being exposed to two messages, delayed in time, which argued opposite positions (initial message and counter‐message). In the first experiment, attitudes following minority endorsement of the initial message were more resistant to a second counter‐message only when the initial message contained strong versus weak arguments. Attitudes changed following majority influence did not resist the second counter‐message and returned to their pre‐test level. Experiment 2 varied whether memory was warned (i.e., message recipients expected to recall the message) or not, to manipulate message processing. When memory was warned, which should increase message processing, attitudes changed following both majority and minority influence resisted the second counter‐message. The results support the view that minority influence instigates systematic processing of its arguments, leading to attitudes that resist counter‐persuasion. Attitudes formed following majority influence yield to counter‐persuasion unless there is a secondary task that encourages message processing. Copyright © 2007 John Wiley & Sons, Ltd.
Label‐Free Impedance Biosensors: Opportunities and Challenges
Authors: Daniels Jonathan S. , Pourmand Nader
Published: May 2007

Impedance biosensors are a class of electrical biosensors that show promise for point‐of‐care and other applications due to low cost, ease of miniaturization, and label‐free operation. Unlabeled DNA and protein targets can be detected by monitoring changes in surface impedance when a target molecule binds to an immobilized probe. The affinity capture step leads to challenges shared by all label‐free affinity biosensors; these challenges are discussed along with others unique to impedance readout. Various possible mechanisms for impedance change upon target binding are discussed. We critically summarize accomplishments of past label‐free impedance biosensors and identify areas for future research.
Preparation of Three‐Dimensional Ordered Macroporous Prussian Blue Film Electrode for Glucose Biosensor Application
Authors: Qiu Jian‐Ding , Peng Hong‐Zhen , Liang Ru‐Ping , Xiong Meng
Published: May 2007

Ordered 3D interconnected macroporous Prussian blue (PB) films were electrochemically fabricated by using colloidal crystals of polystyrene beads as sacrificial templates. The prepared PB film electrodes have excellent catalytic activity towards the reduction of hydrogen peroxide. The PB structure was further used as functional interface for fabricating an enzyme‐based glucose sensor by using surface modification technique based on the electrostatic interactions. The resulted sensor has higher functional density, and larger surface area. The interconnected macroporous structure allows enhanced mass transport. These characteristics of the sensor enable us to detect glucose with high sensitivity. Therefore, the present 3D ordered macroporous film sensor exhibits wide linear detection range towards glucose, acceptable reproducibility and operational and storage stability. The present approach is promising for the generation of high‐enzyme‐content thin films with tailored bioactivity.
Electrochemistry and Electrocatalysis of a Nafion/Nano‐CaCO3/Hb Film Modified Carbon Ionic Liquid Electrode Using BMIMPF6 as Binder
Authors: Sun Wei , Gao Rui‐fang , Jiao Kui
Published: May 2007

In this paper a room temperature ionic liquid 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIMPF6) was used as binder for the construction of carbon ionic liquid electrode (CILE) and a new electrochemical biosensor was developed for determination of H2O2 by immobilization of hemoglobin (Hb) in the composite film of Nafion/nano‐CaCO3 on the surface of CILE. The Hb modified electrode showed a pair of well‐defined, quasi‐reversible redox peaks with Epa and Epc as −0.265 V and −0.470 V (vs. SCE). The formal potential (E°′) was got by the midpoint of Epa and Epc as −0.368 V, which was the characteristic of Hb Fe(III)/Fe(II) redox couples. The peak to peak separation was 205 mV in pH 7.0 Britton–Robinson (B–R) buffer solution at the scan rate of 100 mV/s. The direct electrochemistry of Hb in the film was carefully investigated and the electrochemical parameters of Hb on the modified electrode were calculated as α=0.487 and ks=0.128 s−1. The Nafion/nano‐CaCO3/Hb film electrode showed good electrocatalysis to the reduction of H2O2 in the linear range from 8.0 to 240.0 μmol/L and the detection limit as 5.0 μmol/L (3σ). The apparent Michaelis–Menten constant (KMapp) was estimated to be 65.7 μmol/L. UV‐vis absorption spectroscopy and FT‐IR spectroscopy showed that Hb in the Nafion/nano‐CaCO3 composite film could retain its native structure.
Manganese Dioxide Graphite Composite Electrodes Formed via a Low Temperature Method: Detection of Hydrogen Peroxide, Ascorbic Acid and Nitrite
Authors: Šljukić Biljana , Compton Richard G.
Published: May 2007

Manganese dioxide modified carbon powder was prepared via a wet impregnation method from the solution of permanganate salt. After heating at 120 °C over night in air, the formation of manganese oxide was confirmed by cathodic stripping voltammetry. The synthesized material was used for fabrication of composite electrodes and their potential application in the field of electroanalysis investigated. The composite electrodes based on the manganese dioxide modified carbon powder proved to be useful as electrodes for detection of hydrogen peroxide, ascorbic acid and nitrite ions.
A Novel Glass Membrane for Low Temperature H2/O2Fuel Cell Electrolytes
Authors: Uma T. , Nogami M.
Published: May 2007

A novel structure for an H2/O2fuel cell with a proton conducting glass electrolyte and a Pt/C catalyst was developed. The performance of the fuel cell, which was impregnated with a glass electrolyte and a gaseous hydrogen–oxygen feed at low temperature in a humidified atmosphere was significantly improved by introducing membrane electrode assemblies (MEAs) consisting of heteropolyacids (HPAs) (phosphotungstic acid, PWA and phosphomolybdic acid, PMA) doped with a P2O5‐SiO2glass electrolyte. The HPAs containing porous glass electrolytes show promise for applications in low temperature H2/O2fuel cells. The electrochemical behaviour of these materials was studied by measuring the current–voltage profile from polarisation curves. A maximum power density of ≈ 35 mW cm–2was obtained at 30 °C and 30% RH (relative humidity) using a PMA/PWA‐P2O5‐SiO2glass electrolyte membrane. The impedance measurements displaying the total cell ohmic resistance for 12 h at 0.5 V were evaluated at 30 °C. The resistance value was 3.5 Ω for an operating time of 12 h. This MEA showed the best and the most stable performance for use in an H2/O2fuel cell.
A hierarchical model for estimating significance levels of non‐parametric linkage statistics for large pedigrees
Authors: Brock Guy N. , Weeks Daniel E. , Sobel Eric , Feingold Eleanor
Published: May 2007

The significance level of a non‐parametric linkage (NPL) statistic is often found by simulation since the distribution of the test statistic is complex and unknown. Ideally, simulation occurs by randomly assigning founder genotypes and then simulating meiotic events for the descendants in the pedigree, commonly referred to as ‘gene dropping’. The missing data pattern in the original pedigree, including lack of phase information (due to unordered genotypes), is then imposed on the simulated pedigree. However, this approach is usually computationally infeasible for larger pedigrees which require Markov chain Monte Carlo (MCMC) techniques to calculate the statistic, as an additional MCMC run is required to estimate the statistic for each gene drop. In this work, we propose a novel method to estimate the significance level of the NPL statistic in large pedigrees. This is accomplished by constructing a hierarchical model, which allows estimation of the NPL statistic variability via separate estimation of the Markov chain and gene dropping variability. The significance level is estimated by fitting a parametric model to the statistic and using the method of moments to obtain parameter estimates. In a simulation study we found our hierarchical model estimates to be very close to the gold standard empirical estimates, and offer substantial improvements over the existing conservative method used by the software SimWalk2. The estimation procedure significantly reduces the computational time relative to the ideal empirical estimate, allowing for an accurate estimate of the significance level in a more manageable amount of time. Genet. Epidemiol. 31, 2007. © 2007 Wiley‐Liss, Inc.
A novel method to express SNP‐based genetic heterogeneity, Ψ, and its use to measure linkage disequilibrium for multiple SNPs, Dg, and to estimate absolute maximum of haplotype frequency
Authors: Yamada Ryo , Matsuda Fumihiko
Published: May 2007

Single nucleotide polymorphisms (SNPs) are important markers to investigate genetic heterogeneity of population and to perform linkage disequilibrium (LD) mapping. We propose a new method, Ψ, to express frequency of 2 haplotypes for Ns di‐allelic SNPs. Using the new expression of haplotype frequency, we propose a novel measure of LD, Dg, not only for SNP pairs but also for multiple markers. The values of Dg for SNP pairs were revealed to be similar to values of conventional pairwise LD indices, D′ and r2, and it was revealed that Dg quantitated components of LD that were not measured by conventional LD indices for SNP pairs. Also we propose a distinct method, Dg‐based absolute estimation, to infer the absolute maximum estimates of haplotype frequency. The result of the Dg‐based absolute estimation of haplotype frequency for SNP pairs were compared with the conventional expectation‐maximization (EM) algorithm and reported that the new method gave better inference than the EM algorithm which converged infrequently to a local extreme. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Exploring causality via identification of SNPs or haplotypes responsible for a linkage signal
Authors: Biernacka Joanna M. , Cordell Heather J.
Published: May 2007

In a small chromosomal region, a number of polymorphisms may be both linked to and associated with a disease. Distinguishing the potential causal sites from those indirectly associated due to linkage disequilibrium (LD) with a causal site is an important problem. This problem may be approached by determining which of the associations can explain the observed linkage signal. Recently, several methods have been proposed to aid in the identification of disease associated polymorphisms that may explain an observed linkage signal, using genotype data from affected sib pairs (ASPs) [Li et al. [2005] Am. J. Hum. Genet. 76:934–949; Sun et al. [2002] Am. J. Hum. Genet. 70:399–411]. These methods can be used to test the null hypothesis that a candidate single nucleotide polymorphism (SNP) is the sole causal variant in the region, or is in complete LD with the sole causal variant in the region. We extend variations of these methods to test for complete LD between a disease locus and haplotypes composed of two or more tightly linked candidate SNPs. We study properties of the proposed methods by simulation and apply them to type 1 diabetes data for ASPs and their parents at candidate SNP and microsatellite marker loci in the Insulin (INS) gene region. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Power of genome‐wide association studies in the presence of interacting loci
Authors: Pickrell Joseph , Clerget‐Darpoux Françoise , Bourgain Catherine
Published: May 2007

Though multiple interacting loci are likely involved in the etiology of complex diseases, early genome‐wide association studies (GWAS) have depended on the detection of the marginal effects of each locus. Here, we evaluate the power of GWAS in the presence of two linked and potentially associated causal loci for several models of interaction between them and find that interacting loci may give rise to marginal relative risks that are not generally considered in a one‐locus model. To derive power under realistic situations, we use empirical data generated by the HapMap ENCODE project for both allele frequencies and linkage disequilibrium (LD) structure. The power is also evaluated in situations where the causal single nucleotide polymorphisms (SNPs) may not be genotyped, but rather detected by proxy using a SNP in LD. A common simplification for such power computations assumes that the sample size necessary to detect the effect at the tSNP is the sample size necessary to detect the causal locus directly divided by the LD measure r2 between the two. This assumption, which we call the “proportionality assumption”, is a simplification of the many factors that contribute to the strength of association at a marker, and has recently been criticized as unreasonable (Terwilliger and Hiekkalinna [2006] Eur J Hum Genet 14(4):426–437), in particular in the presence of interacting and associated loci. We find that this assumption does not introduce much error in single locus models of disease, but may do so in so in certain two‐locus models. Genet. Epidemiol. 2007. © 2007 Wiley‐Liss, Inc.
Comparison of admixture and association mapping in admixed families
Authors: Clarke Geraldine , Whittemore Alice S.
Published: May 2007

The family‐based admixture mapping test (AMT) identifies disease‐related genes using family data from admixed individuals with the disease of interest (cases). The cases' genotypes at a set of markers are used to infer their DNA ancestry as it varies in blocks along the chromosomes. The test compares the cases' inferred ancestries to those expected from their family histories. Deviation between observed and expected ancestries in a region suggests the presence of a disease gene. We use a likelihood‐based development of the AMT to compare it with the transmission disequilibrium test (TDT) as applied to admixed populations. The two tests have a common framework but differ significantly when the disease locus is untyped. The TDT infers disease‐locus genotypes using the markers with which it is in linkage disequilibrium (LD). In contrast, the AMT infers disease locus ancestries using those of its linked markers. Thus, TDT power depends on LD between disease and marker loci, while AMT power depends on the lengths of the ancestry blocks containing the disease locus. We compare the power of the two tests when applied to cases with descent from two ancestral populations. The AMT outperforms the TDT when case marker ancestries are correctly specified and LD between disease and marker loci is less than one‐third its maximal value (Δ′<1/3). However, the TDT performs better in the presence of uncertain marker ancestries, even for weak LD between disease and marker loci (Δ′ = 0.1). These findings have implications for the design of studies using admixed populations. Genet. Epidemiol. 31, 2007. © 2007 Wiley‐Liss, Inc.
Synergistic induction of cyclin D1 in oligodendrocyte progenitor cells by IGF‐I and FGF‐2 requires differential stimulation of multiple signaling pathways
Authors: Frederick Terra J. , Min Jungsoo , Altieri Stefanie C. , Mitchell Nina E. , Wood Teresa L.
Published: May 2007

D‐type cyclins are direct targets of extracellular signals and critical regulators of G1 progression. Our previous data demonstrated that IGF‐I and FGF‐2 synergize to enhance cyclin D1 expression, cyclin E/cdk2 complex activation, and S‐phase entry in OP cells. Here, we provide a mechanistic explanation for how two growth factor signaling pathways converge on a major cell cycle regulator. IGF‐I and FGF‐2 differentially activate signaling pathways to coordinately promote cyclin D1 expression. We show that the p44/p42 MAPK signaling pathway is essential for FGF‐2 induction of cyclin D1 mRNA. In contrast, blocking the PI3‐Kinase pathway results in loss of IGF‐I/FGF‐2 synergistic induction of cyclin D1 protein levels. Moreover, the presence of IGF‐I significantly enhances nuclear localization of cyclin D1, which also requires PI3K signaling. GSK‐3β, a downstream target of the PI3K/Akt pathway, is phosphorylated in the presence of IGF‐I in OPs. Consistent with a known role for GSK‐3β in cyclin D1 degradation, we show that proteasome inhibition in OPs exposed to FGF‐2 increased cyclin D1 levels, equivalent to levels seen in IGF‐I/FGF‐2 treated cells. Thus, we provide a model for cyclin D1 coordinate regulation where FGF‐2 stimulation of the MAPK pathway promotes cyclin D1 mRNA expression while IGF‐I activation of the PI3K pathway inhibits proteasome degradation of cyclin D1 and enhances nuclear localization of cyclin D1. © 2007 Wiley‐Liss, Inc.
Differential prognostic impact of comorbidity in head and neck cancer
Authors: Alho Olli‐Pekka , Hannula Kalle , Luokkala Antti , Teppo Heikki , Koivunen Petri , Kantola Saara
Published: May 2007

Background.

The aim was to investigate how the effect of comorbid illnesses on survival is modified by other prognostic factors in head and neck cancer.

Methods.

A population‐based retrospective cohort study involved 221 patients residing in 1 primary health care district (population about 700,000) in whom head and neck carcinoma was diagnosed between January 1, 1986, and December 31, 1996. Data on clinical characteristics and survival were obtained from patient charts. Comorbidity was classified according to Charlson score.

Results.

At 3 years, the risk of death was significantly higher among the patients with high comorbidity status (score 3 or higher) (adjusted hazard ratio 2.1, 95% confidence interval 1.2–3.7). The excess risk associated with comorbidity, however, was confined to the subjects aged under 65 years and those with tongue or laryngeal tumors or stage I–II cancer.

Conclusion.

To assess the prognostic significance of comorbidity for an individual patient with head and neck cancer, age, tumor site, and cancer stage must be considered. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Quality of life and voice in patients after laser cordectomy for TIS and T1 glottic carcinomas
Authors: Roh Jong‐Lyel , Kim Dong‐Hyun , Yoon Kim Sang , Park Chan Il
Published: May 2007

Background.

Laser cordectomy is gaining popularity for treatment of early glottic carcinoma, but little is known about vocal and quality of life (QOL) outcomes as a function of extent of resection. We prospectively examined QOL and vocal function of patients with carcinoma in situ (Tis) or T1 glottic carcinomas after laser cordectomy.

Methods.

Patients (n = 75) were grouped into those who underwent unilateral subepithelial or subligamental resection (group A, n = 45); those who underwent unilateral transmuscular or total cordectomy (group B, n = 17); and those who underwent extended or bilateral cordectomy including the anterior commissure (group C, n = 19). The European Organization for Research and Treatment of Cancer head and neck cancer specific module (QLQ‐H&N35), voice handicap index (VHI), and objective vocal function were examined before and 1 year after cordectomy and compared among the groups.

Results.

No major complications were encountered, but local recurrence occurred in 10 patients, with group C showing the highest rate (6/19, 31.6%). Patient‐reported speech and social contact scores of QOL questionnaire and VHI scores after surgery were higher in groups B and C than in group A (p < .05). The scores and perceptual and acoustic data were generally improved in all groups after surgery, but were statistically significant only in group A (p < .03).

Conclusion.

Our data suggest that early glottic cancers with a limited extent and infiltration depth have improved outcomes, both oncologically and functionally, compared to those lesions requiring extensive laser resection. © 2007 Wiley Periodicals, Inc. Head Neck 2007
Synthesis of Benzodioxepinone Analogues via a Novel Synthetic Route with Qualitative Olfactory Evaluation
Authors: Drevermann Britta , Lingham Anthony R. , Hügel Helmut M. , Marriott Philip J.
Published: May 2007

Marine odorants represent a minor yet diverse class of substances within the fragrance industry, of which 7‐methyl‐2H‐1,5‐benzodioxepin‐3(4H)‐one (1) is commercially known as Calone 1951®, a synthetic first in the area of marine‐fragrance chemistry. To determine the extent to which the characteristic marine odor of Calone 1951® corresponds to the substitution at the benzo portion of the molecule, a variety of aromatic substituents were incorporated into the benzodioxepinone structure (Scheme 1, Table 3). In light of the difficulty experienced in applying patented literature to deriving the analogues 12–18, particularly those with electron‐withdrawing substituents, an alternative synthetic scheme was implemented for the construction of all analogues in favorable yields (Scheme 4, Table 3). Formation of the hydroxy‐protected dihalo alkylating agent 24 via epoxide cleavage of epichlorohydrin (Scheme 3) allowed etherification favoring dihalo displacement and subsequent intramolecular ring closure (→26a–g). THP Deprotection followed by oxidation of the alcohols 27a–g to the ketones 12–18 provided a general pathway to the benzodioxepinone products. The influence of the substituent nature on odor activity revealed a diverse scope of olfactory character (Table 4).
Sesquiterpenoids and Lactone Derivatives from Ligularia dentata
Authors: Baba Hitomi , Yaoita Yasunori , Kikuchi Masao
Published: May 2007

Seven new compounds were isolated from the roots of Ligularia dentata, including five bisabolane‐type sesquiterpenoids (bisabolane=1‐(1,5‐dimethylhexyl)‐4‐methylcyclohexane), namely (8β,10α)‐8‐(angeloyloxy)‐5,10‐epoxybisabola‐1,3,5,7(14)‐tetraene‐2,4,11‐triol (1), (8β,10α)‐8‐(angeloyloxy)‐5,10‐epoxythiazolo[5,4‐a]bisabola‐1,3,5,7(14)‐tetraene‐4,11‐diol (2), (1α,2α,3β,5α,6β)‐1,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐2,3‐dihydroxybisabol‐7(14)‐en‐4‐one (3), (1α,2α,3β,5α,6β)‐2,5,8‐tris(angeloyloxy)‐10,11‐epoxy‐1,3‐dihydroxybisabol‐7(14)‐en‐4‐one (4), and (1α,2β,3β,5α,6β)‐1,8‐bis(angeloyloxy)‐2,3‐epoxy‐5,10‐dihydroxy‐11‐methoxybisabol‐7(14)‐en‐4‐one (5) (angeloyloxy=[(2Z)‐2‐methyl‐1‐oxobut‐2‐enyl]oxy), and two lactone derivatives, (2α,3β,5α)‐2‐(acetyloxy)‐9‐methoxy‐5‐(methoxycarbonyl)‐2,3‐dimethylheptano‐5‐lactone (6), and (2β,4β)‐2‐ethyl‐5‐hydroxy‐5‐(methoxycarbonyl)‐4,5‐dimethylpentano‐4‐lactone (7) (α/β denote relative configurations), together with (2E,4R,5S)‐2‐ethylidene‐5‐(methoxycarbonyl)‐4‐methylhexano‐5‐lactone (8), a known synthetic compound. Compound 2 is the first sesquiterpenoid derivative containing the uncommon benzothiazole moiety. The structures of 1–8 were established by spectroscopic methods, especially 2D‐NMR and MS analyses.
Steroidal Alkaloids from the Roots and Rhizomes of Vertrum nigrum L.
Authors: Cong Yue , Jia William , Chen Jing , Song Shuang , Wang Jin‐Hui , Yang Yu‐Hui
Published: May 2007

Two new steroidal alkaloids, neoverapatuline (1) and (1β,3α,5β)‐1,3‐dihydroxyjervanin‐12‐en‐11‐one (2), together with the four known compounds, veratramine (3), rubijervine (4), veratrosine (5), and veratroylzygadenine (6), were isolated from the roots and rhizomes of Veratrum nigrum L. Their structures were established through combined analyses of physicochemical properties and spectroscopic evidence. All compounds 1–6 were tested for their cytotoxicities in vitro against the human glioma cell line SF188.
Oligonucleotide Analogues with Integrated Bases and Backbone. Part 16
Authors: Zhang Xiaomin , Bernet Bruno , Vasella Andrea
Published: May 2007

The self‐complementary, ethylene‐linked U*[ca]A(*) dinucleotide analogues 8, 10, 12, 14, 16, and 18, and the sequence‐isomeric A*[ca]U(*) analogues 20, 22, 24, 26, 28, and 30 were obtained by Pd/C‐catalyzed hydrogenation of the corresponding, known ethynylene‐linked dimers. The association of the ethylene‐linked dimers was investigated by NMR and CD spectroscopy. The U*[ca]A(*) dimers form linear duplexes and higher associates (K between 29 and 114M−1). The A*[ca]U(*) dimers, while associating more strongly (K between 88 and 345M−1), lead mostly to linear duplexes and higher associates; they form only minor amounts of cyclic duplexes. The enthalpy–entropy compensation characterizing the association of the U*[cx]A(*) and A*[cx]U(*) dimers (x=y, e, and a) is discussed.
Oligodeoxynucleotides Containing 2′‐Deoxy‐1‐methyladenosine andDimrothRearrangement
Authors: Timofeev Edward N. , Mikhailov Sergey N. , Zuev Andrei N. , Efimtseva Ekaterina V. , Herdewijn Piet , Somers Robert L. , Lemaitre Marc M.
Published: May 2007

2′‐Deoxy‐1‐methyladenosine was incorporated into synthetic oligonucleotides by phosphoramidite chemistry. Chloroacetyl protecting group and controlled anhydrous deprotection conditions were used to avoidDimrothrearrangement. Hybridization studies of intramolecular duplexes showed that introduction of a modified residue into the loop region of the oligonucleotide hairpin increases the melting temperature. It was shown that modified oligonucleotides may be easily transformed into oligonucleotides containing 2′‐deoxy‐N6‐methyladenosine.
Two New Lignan Glycosides from Saussurea laniceps
Authors: Zhou Zhi‐Wang , Yin Sheng , Wang Xiao‐Ning , Fan Cheng‐Qi , Li Hui , Yue Jian‐Min
Published: May 2007

Two new lignan glycosides, lanicepsides A and B (1 and 2), along with the eight known compounds 3–6, epipinoresinol, syringin, ethyl caffeate, and 5,6,7‐trihydroxy‐4′‐methoxyflavone, including sesquiterpene lactones, lignans, and a flavone, were isolated from the ethanol extract of Saussurea laniceps. Their structures were determined by spectroscopic methods especially 1D‐ and 2D‐NMR techniques.
Liquid‐Crystalline Mixed [5 : 1]Hexa‐adducts of [60]Fullerene. Preliminary Communication
Authors: Gottis Sébastien , Kopp Cyril , Allard Emmanuel , Deschenaux Robert
Published: May 2007

A liquid‐crystalline mixed [5 : 1]hexa‐adduct of [60]fullerene was synthesized by addition of two different malonate derivatives onto C60. The hexa‐adduct derivative 2 was prepared by a stepwise synthetic procedure (fullerene→mono‐adduct of C60→hexa‐adduct of C60). Cyanobiphenyl and octyloxybiphenyl derivatives were selected as mesogens. The malonate derivatives showed either a monotropic nematic phase or a monotropic smectic A phase, and the hexa‐adduct derivative gave rise to an enantiotropic smectic A phase.
Synthetic Studies on Coenzyme Q10. Part 3
Authors: Yu Xiong‐Jie , Dai Hui‐Fang , Chen Fen‐Er
Published: May 2007

An efficient and stereoselective approach to the synthesis of coenzyme Q10 is described (Scheme). The MeOCH2‐protected p‐hydroquinone 4 containing the C5 (E)‐allyl (tert‐butyl)dimethylsilyl ether moiety was obtained via a halogen–lithium exchange of the MeOCH2‐proctected 2‐bromo‐5,6‐dimethoxy‐3‐methylhydroquinone 2 and subsequent addition to (E)‐(tBuMe2Si)‐OCH2C(Me)=CHCH2Br (3). The reductive desulfonylation of compound 8, obtained from 4 via 5–7, was successfully carried out by employing Li/EtNH2.
Two New Iridoid Alkaloids, Daphmacropodosidines A and B, from Daphniphyllum macropodum
Authors: Kong Ning‐Chuan , He Hong‐Ping , Wang Yue‐Hu , Gao Suo , Di Yun‐Tong , Hao Xiao‐Jiang
Published: May 2007

Two new iridoid alkaloids, daphmacropodosidines A (1) and B (2), together with two known ones, daphcalycinosidine B and caldaphnidine F, were isolated from the fruits of Daphniphyllum maropodum. Their structures were established by spectral methods, especially 2D NMR spectra (1H,1H‐COSY, HMQC, HMBC, and NOESY), as well as chemical means.
Stereoselective and Enantioselective Syntheses of the Four Stereoisomers of Muscol from (3RS)‐Muscone
Authors: Yuasa Yoshifumi , Fukaya Haruhiko , Yuasa Yoko
Published: May 2007

Two trans stereoisomers of 3‐methylcyclopentadecanol (=muscol), (1R,3R)‐2 and (1S,3S)‐2, were efficiently synthesized from (3RS)‐3‐methylcyclopentadecanone (=muscone; (3RS)‐1) by a highly stereoselective reduction (Scheme). L‐Selectride® (=lithium tri(sec‐butyl)borohydride) was used, followed by the enantiomer resolution by lipase QLG (Alcaligenes sp.). The cis stereoisomers of muscol, (1S,3R)‐2 and (1R,3S)‐2, were obtained by the Mitsunobu inversion of (1R,3R)‐2 and (1S,3S)‐2, respectively (Scheme). The absolute configuration of (1R,3R)‐2 was determined by X‐ray crystal‐structure analysis of its 3‐nitrophthalic acid monoester, 2‐[(1R,3R)‐3‐methylcyclopentadecyl hydrogen benzene‐1,2‐dicarboxylate ((1R,3R)‐3b), and by oxidation of (1R,3R)‐2 to (3R)‐muscone.
Reactions of Di(tert‐butyl)diazomethane with Acceptor‐Substituted Ethylenes
Authors: Huisgen Rolf , Pöchlauer Peter , Mlostoń Grzegorz , Polborn Kurt
Published: May 2007

Di(tert‐butyl)diazomethane (4) is a nucleophilic 1,3‐dipole with strong steric hindrance at one terminus. In its reaction with 2,3‐bis(trifluoromethyl)fumaronitrile ((E)‐BTE), a highly electrophilic tetra‐acceptor‐substituted ethene, an imino‐substituted cyclopentene 9 is formed as a 1 : 2 product. The open‐chain zwitterion 10, assumed as intermediate, adds the second molecule of (E)‐BTE. The 19F‐ and 13C‐NMR spectra allow the structural assignment of two diastereoisomers, 9A and 9B. The zwitterion 10 can also be intercepted by dimethyl 2,3‐dicyanofumarate (11) and furnishes diastereoisomeric cyclopentenes 12A and 12B; an X‐ray‐analysis of 12B confirms the ‘mixed’ 1 : 1 : 1 product. Competing is an (E)‐BTE‐catalyzed decomposition of 4 to give 2,3,4,4‐tetramethylpent‐1‐ene (7)+N2; the reaction of (E)‐BTE with a trace of water appears to be responsible for the chain initiation. The H2SO4‐catalyzed decomposition of diazoalkane 4, indeed, produced the alkene 7 in high yield. The attack on the hindered diazoalkane 4 by 11 is slower than that by (E)‐BTE; the zwitterionic intermediate 21 undergoes cyclization and furnishes the tetrasubstituted furan 22. In fumaronitrile, electrophilicity and steric demand are diminished, and a 1,3‐cycloaddition produces the 4,5‐dihydro‐1H‐pyrazole derivative 25. The reaction of 4 with dimethyl acetylenedicarboxylate leads to pyrazole 29+isobutene.
Simulating watershed runoff with a new data model
Authors: Reitsma Femke , Dubayah Ralph
Published: May 2007

This paper presents the implementation of a new data model for simulating watershed runoff. This data model, called nen, allows users to visualize and analyse the processes that are simulated in the watershed runoff model. It extends data models typically used in modelling watershed runoff, such as raster, that do not give direct insight into the spatial dynamics and distribution of the processes expressed in the model. Data from the Upper Sheep Creek sub‐watershed in the Reynolds Creek Experimental Watershed was used to illustrate the methodology within the context of runoff simulation. Model results, while consistent with standard approaches to validation against a hydrograph, require new methods of validation for testing the process descriptions and simulated process results that are unique outputs of this model. Future developments aim at creating analytical and validation techniques and further developing the simulator to allow for larger scale modelling. Copyright © 2007 John Wiley & Sons, Ltd.
A semi‐theoretical model of canopy rainfall interception for a broad‐leaved tree
Authors: Wang Anzhi , Diao Yiwei , Pei Tiefan , Jin Changjie , Zhu Jiaojun
Published: May 2007

Through a series of simulation experiments in the laboratory on the broad‐leaved tree Acer mono Maxim, we obtain interception datasets of individual events under different rainfall intensities and leaf area indexes (LAIs). Based on the data, the relationship between rainfall intensity and maximum interception of per unit LAI is quantified. The variation of interception with canopy wetness index is also identified. Hence, an interception model, in which interception is calculated using rainfall intensity and LAI, is constructed with consideration of canopy wetness. Finally, according to the validation experiments, it is concluded that the precision of the model is 92·7%. Copyright © 2007 John Wiley & Sons, Ltd.
Enhancements to, and forthcoming developments in the Interactive Multisensor Snow and Ice Mapping System (IMS)
Authors: Helfrich Sean R. , McNamara Donna , Ramsay Bruce H. , Baldwin Thomas , Kasheta Tim
Published: May 2007

The National Oceanic and Atmospheric Administration's National Environmental Satellite Data and Information Service (NOAA/NESDIS) Interactive Multisensor Snow and Ice Mapping System (IMS) has undergone substantial changes since its inception in 1997. These changes include the data sources used to generate the product, methodology of product creation, and even changes in the output. Among the most notable of the past upgrades to the IMS are a 4‐km resolution grid output, ingest of an automated snow detection algorithm, expansion to a global extent, and a static Digital Elevation Model for mapping based on elevation. Further developments to this dynamic system will continue as NOAA strives to improve snow parameterization for weather forecast modeling. Several future short‐term enhancements will be evaluated for possible transition to operations before the Northern Hemisphere winter of 2006–2007. Current and historical data will be adopted to a geographic information systems (GIS) format before 2007, as well. Longer‐term enhancements are also planned to account for new snow data sources, mapping methodologies and user requirements. These modifications are being made with care to preserve the integrity of the long‐standing satellite‐derived snow record that is vital to global change detection. Published in 2007 by John Wiley & Sons, Ltd.
AMSR‐E algorithm for snowmelt onset detection in sub‐arctic heterogeneous terrain
Authors: Apgar Jeremy D. , Ramage Joan M. , McKenney Rose A. , Maltais Patrick
Published: May 2007

The onset of snowmelt in the upper Yukon River basin, Canada, can be derived from brightness temperatures (Tb) obtained by the Advanced Microwave Scanning Radiometer for EOS (AMSR‐E) on NASA's Aqua satellite. This sensor, with a resolution of 14 × 8 km2 for the 36·5 GHz frequency, and two to four observations per day, improves upon the twice‐daily coverage and 37 × 28 km2 spatial resolution of the Special Sensor Microwave Imager (SSM/I). The onset of melt within a snowpack causes an increase in the average daily 36·5 GHz vertically polarized Tb as well as a shift to high diurnal amplitude variations (DAV) as the snow melts during the day and re‐freezes at night. The higher temporal and spatial resolution makes AMSR‐E more sensitive to sub‐daily Tb oscillations, resulting in DAV that often show a greater daily range compared to SSM/I. Therefore, thresholds of Tb > 246 K and DAV > ± 10 K developed for use with SSM/I have been adjusted for detecting the onset of snowmelt with AMSR‐E using ground‐based surface temperature and snowpack wetness relationships. Using newly developed thresholds of Tb > 252 K and DAV > ± 18 K, AMSR‐E derived snowmelt onset correlates well with SSM/I observations in the small subarctic Wheaton River basin through the 2004 and 2005 winter/spring transition. In addition, the onset of snowmelt derived from AMSR‐E data gridded at a higher resolution than the SSM/I data indicates that finer‐scale differences in elevation and land cover affect the onset of snowmelt and are detectable with the AMSR‐E sensor. On the basis of these observations, the enhanced resolution of AMSR‐E is more effective than SSM/I at delineating spatial and temporal snowmelt dynamics in the heterogeneous terrain of the upper Yukon River basin. Copyright © 2007 John Wiley & Sons, Ltd.
Insulin receptor substrate 1 (IRS‐1) plays a unique role in normal epidermal physiology
Authors: Sadagurski Marianna , Nofech‐Mozes Sharon , Weingarten Galina , White Morris F. , Kadowaki Takashi , Wertheimer Efrat
Published: May 2007

Insulin receptor substrate (IRS) proteins play a central role in insulin signaling. Previously we have demonstrated that insulin is essential for normal skin development and function. In the present study we investigated the involvement of the IRS‐1 and IRS‐2 proteins in skin physiology and in mediating insulin action in skin. For this purpose we have investigated the effects of inactivation of each of the IRSs on skin, studying skin sections and primary skin cells derived from IRS‐1 or IRS‐2 null mice. We have demonstrated that while the skin of the IRS‐2 null mice appeared normal, the skin of the IRS‐1 null mice was thinner and translucent. Histological analysis revealed that the thinning of the IRS‐1 null skin was a consequence of the thinning of the spinous compartment, consisting of fewer layers. Proliferation of the IRS‐1 and IRS‐2 null skin epidermal cells was normal. However, the differentiation process of the IRS‐1 skin and skin cells was impaired. There was a marked decrease in the induction of the expression of K1, the marker of advanced stages of skin differentiation. In contrary, IRS‐2 inactivation had no effects on skin differentiation. In conclusion, we have shown for the first time that IRS‐1 but not IRS‐2 has an effect on skin formation and development, being one of the main activators of the differentiation process in skin keratinocytes. Furthermore, we suggest that IRS‐1 and IRS‐2 have distinct roles in skin physiology. J. Cell. Physiol. 213: 519–527, 2007. © 2007 Wiley‐Liss, Inc.
Actin polymerization modulates CD44 surface expression, MMP‐9 activation, and osteoclast function
Authors: Samanna V. , Ma T. , Mak T.W. , Rogers M. , Chellaiah M.A.
Published: May 2007

CD44 and MMP‐9 are implicated in cell migration. In the current study, we tested the hypothesis that actin polymerization is critical for CD44 surface expression and MMP‐9 activity on the cell surface. To understand the underlying molecular mechanisms involved in CD44 surface expression and MMP‐9 activity on the cell surface, osteoclasts were treated with bisphosphonate (BP) alendronate, cytochalasin D (Cyt D), and a broad‐spectrum MMP inhibitor (GM6001). BP has been reported to block the mevalonate pathway, thereby preventing prenylation of small GTPase signaling required for actin cytoskeleton modulation. We show in this study that osteoclasts secrete CD44 and MMP‐9 into the resorption bay during migration and bone resorption. Results indicate that actin polymerization is critical for CD44 surface expression and osteoclast function. In particular, the surface expression of CD44 and the membrane activity of MMP‐9 are reduced in osteoclasts treated with alendronate and Cyt D despite the membrane levels of MMP‐9 being unaffected. Although GM6001 blocked MMP‐9 activity, osteoclast migration, and bone resorption, the surface levels of CD44 were unaffected. We suggest that the surface expression of CD44 requires actin polymerization. Disruption of podosome and actin ring structures by Cyt D and alendronate not only resulted in reduced localization of MMP‐9 in these structures but also in osteoclast migration and bone resorption. These results suggest that inhibition of actin polymerization by alendronate and Cyt D is effective in blocking CD44/MMP‐9 complex formation on the cell surface, secretion of active form of MMP‐9, and osteoclast migration. CD44/MMP‐9 complex formation may signify a unique motility‐enhancing signal in osteoclast function. J. Cell. Physiol. 213:710–720. © 2007 Wiley‐Liss, Inc.
Transient receptor potential vanilloid 1 activation induces inflammatory cytokine release in corneal epithelium through MAPK signaling
Authors: Zhang Fan , Yang Hua , Wang Zheng , Mergler Stefan , Liu Hongshan , Kawakita Tetsuya , Tachado Souvenir D. , Pan Zan , Capó‐Aponte José E. , Pleyer Uwe , Koziel Henry , Kao Winston W.Y. , Reinach Peter S.
Published: May 2007

In certain epithelial tissues, activation of transient receptor potential (TRP) vanilloid subtype 1 (TRPV1) by noxious stimuli induces pro‐inflammatory cytokine release, which helps to mitigate the challenge. While the corneal epithelium elicits such responses to a variety of challenges, it remains unknown whether TRPV1 mediates pro‐inflammatory cytokine secretion. Accordingly, we probed for TRPV1 expression and function in human (HCEC) and rabbit corneal epithelial cell (RCEC) lines, in their primary counterparts, and in human and mouse corneal epithelium in situ. Cell membrane and perinuclear TRPV1 expression was detected in all preparations and its identity verified by Western blot analysis. Capsaicin (CAP) (1–10 µM) increased nonselective cation channel whole cell currents (2.5‐fold ± 0.5‐fold between −60 and 130 mV), resulting in calcium transients that were fully blocked by the TRPV1 antagonists capsazepine (CPZ) and ruthenium red, or removal of extracellular calcium. Another signaling event involved transient activation of global mitogen‐activated protein kinase (MAPK) superfamily, which was followed by up to 3.3‐ and 9‐fold increases in interleukins (IL)‐6 and ‐8 release, respectively. Such increases in inflammatory mediators' release were suppressed by exposure to CPZ or MAPK inhibitors, or removal of Ca2+. Taken together, TRPV1 receptors may play a role in mediating corneal epithelial inflammatory mediator secretion and subsequent hyperalgesia. J. Cell. Physiol. 213:730–739. © 2007 Wiley‐Liss, Inc.
Anomeric information obtained from a series of synthetic trisaccharides using energy resolved mass spectra
Authors: Daikoku Shusaku , Ako Takuro , Kurimoto Ayako , Kanie Osamu
Published: May 2007

The majority of structural investigations of oligosaccharides based on mass spectrometry use naturally occurring oligosaccharides, which do not allow extracting any common feature associated with anomeric structures and linkage positions. In order to address the issue to find such characteristics possibly contained in oligosaccharide structure, a synthetic combinatorial trisaccharide library was analyzed. The trisaccharides used in the analysis consisted of L‐fucose, D‐galactose and D‐glucose, in which individual glycosidic linkages existed in either α‐ or β‐anomers. The analysis of energy‐resolved mass spectra (ERMS) and the scattered plot analysis of some parameters obtained from ERMS for a series of trisaccharides revealed that lower activation energy was required for the dissociation of α‐glycosides of these sugars compared to those of the corresponding β‐anomers. It is suggested that this finding may be useful in structural analysis of natural oligosaccharides. Copyright © 2007 John Wiley & Sons, Ltd.
A sensitive and selective liquid chromatography‐tandem mass spectrometry method for the simultaneous quantification of actinomycin‐D and vincristine in children with cancer
Authors: Lee James I. , Skolnik Jeffrey M. , Barrett Jeffrey S. , Adamson Peter C.
Published: May 2007

We describe a selective and a highly sensitive assay for actinomycin‐D (Act‐D) and vincristine (VCR) in plasma employing high‐performance liquid chromatography‐tandem mass spectrometry (HPLC‐MS/MS) detection. The intraday precision (as defined by the coefficient of variation, CV) based on the standard deviation of replicates of quality control samples ranged from 4.9 to 7.5% and 6.5 to 11.3% with accuracy ranging from 90.7 to 98.1% and 91.2 to 103% for Act‐D and VCR, respectively. The interday precision ranged from 7.2 to 10.0% and 11.3 to 13.0% and the accuracy ranged from 94.3 to 102% and 90.7 to 91.6% for Act‐D and VCR, respectively. Stability studies showed that Act‐D and VCR were stable both during the assay procedure and long‐term storage. The lower limit of quantitation (LLOQ) for both Act‐D and VCR was 0.05 ng/ml. The analytical method showed excellent sensitivity, precision, and accuracy. This method is robust and is being successfully employed in a pharmacokinetic study of these agents in children with cancer, and is expected to support several ongoing and future pediatric trials. Copyright © 2007 John Wiley & Sons, Ltd.
Hollow‐fiber liquid‐phase microextraction prior to low‐temperature electrothermal vaporization ICP‐MS for trace element analysis in environmental and biological samples
Authors: Xia Linbo , Wu Yunli , Hu Bin
Published: May 2007

A new method of hollow‐fiber liquid‐phase microextraction (HF‐LPME) prior to electrothermal vaporization (ETV) inductively coupled plasma mass spectrometry (ICP‐MS) determination of trace Cu, Zn, Pd, Cd, Hg, Pb and Bi, based on gaseous compounds introduction into the plasma as their diethyldithiocarbmate (DDTC) chelates, was developed. The use of the reagent DDTC as chemical modifier could not only enhance the analytical signals, but also decrease the vaporization temperature. At a temperature of 1300 °C, trace Cu, Zn, Pd, Cd, Hg, Pb and Bi can be vaporized completely into the ICP. The factors affecting the formation of the chelates and their vaporization behaviors were investigated in detail, and the microextraction conditions were optimized. Under the optimized conditions, the detection limits of the proposed method were 12.4, 28.7, 7.9, 4.5, 3.3, 4.8 and 1.6 pg ml−1 for Cu, Zn, Pd, Cd, Hg, Pb and Bi, respectively. Enrichment factors of 305, 284, 24, 29, 20, 73 and 43 could be achieved within 15 min of extraction time, and the relative standard deviations (RSDs) for the seven determinations of 0.5 ng ml−1 of target analytes were 8.8, 6.9, 7.1, 9.4, 10.2, 6.1 and 10.8%, respectively. The newly developed method has been applied to the determination of trace Cu, Zn, Pd, Cd, Hg, Pb and Bi in environmental water and human serum samples, and the recoveries for the spiked samples were in the range of 88–116%. In order to validate this method, two certified reference materials, GBW08501 peach leaves and GBW(E)080040 seawater, were analyzed, and the determined values were in good agreement with the certified values. Copyright © 2007 John Wiley & Sons, Ltd.