bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of pressure drop on absolute retention matching in comprehensive two‐dimensional gas chromatography
Authors: Shellie Robert , Marriott Philip , Morrison Paul , Mondello Luigi 
Published: May 2004

AbstractComprehensive two‐dimensional gas chromatography (GC×GC) analysis has the capability to resolve many more components of complex mixtures than traditional single column GC analysis. There is an increasing need to provide reliable identification of these separated components; time‐of‐flight mass spectrometry (TOFMS) is the most appropriate technology to achieve this task. Rather than require MS for all GC×GC separations, it is desirable to assign peak identities to specific peak positions in the GC×GC separation space, and this necessitates matching peak retentions in the two experiments – GC×GC‐FID and GC×GC‐TOFMS. The atmospheric vs. vacuum outlet conditions confound this task. It is shown here that by employing a supplementary gas supply, provided to a T‐union between the column outlet and the MS interface, it is possible to generate 2D chromatograms for GC×GC‐FID and GC×GC‐TOFMS that are essentially exactly matched. There is no degradation in separation performance or efficiency in the second column in the system interfaced to the T‐union. Since the GC×GC‐FID experiment uses hydrogen for maximum efficiency, and GC×GC‐TOFMS uses helium carrier, translation of (conditions/retentions) must account for the different viscosities of the carrier gases. Translation of conditions is based on well‐known principles established in single column analysis. Tabulated data illustrate that retention reproducibility was of the order of better than 4 s for the average first dimension retention difference, and about 40 ms for the average second dimension retention difference when comparing GC×GC‐FID and GC×GC‐TOFMS results. This should provide considerable support for identification in routine GC×GC‐FID analysis of specific sample types, once the peaks in 2D separation space have been assigned identities through GC×GC‐TOFMS analysis.
Rural tourism development in southeastern Europe: transition and the search for sustainability
Authors: Hall Derek 
Published: May 2004

AbstractThis paper evaluates current issues surrounding the role and development of rural tourism in southeastern Europe (SEE) (Romania, Bulgaria, Albania and much of former Yugoslavia), setting this within the wider context of change in post‐communist central and eastern Europe (CEE). It examines local and global factors of development and change, particularly within the context of aspirations towards sustainability. The paper concludes that the impacts of EU membership — both of the 2004 enlargement, and later potentially for the countries of southeastern Europe themselves — is likely to be crucial in market and product development for rural tourism. Copyright © 2004 John Wiley & Sons, Ltd.
Functionalization of Multi‐Walled Carbon Nanotubes by Electrografting of Polyacrylonitrile
Authors: Petrov Petar , Lou Xudong , Pagnoulle Christophe , Jérôme Christine , Calberg Cédric , Jérôme Robert 
Published: May 2004

AbstractSummary: Multi‐walled carbon nanotubes (MWNTs) have been successfully modified with polyacrylonitrile (PAN) by a cathodic electrochemical process. The surface‐modified MWNTs afforded are then dispersible in good solvents for PAN, such as N,N‐dimethylformamide (DMF). Collected from a dilute dispersion, these MWNTs are essentially disentangled, as confirmed by transmission electron microscopy (TEM) analysis. From the differential scanning calorimetry (DSC) traces for polyacrylonitrile and polyacrylonitrile‐grafted MWNTs, the maximum grafting ratio is estimated at 0.28.Electrochemical grafting of polyacrylonitriles onto the surface of multi‐walled carbon nanotubes.magnified imageElectrochemical grafting of polyacrylonitriles onto the surface of multi‐walled carbon nanotubes.
Structure of polyelectrolyte solutions: influence of salt and chain flexibility
Authors: Winkler Roland G. 
Published: May 2004

AbstractThe structural properties of polyelectrolyte solutions with and without added salt are investigated using an integral equation theory approach. For rodlike systems, all components of the solution (polyions, counterions, anions, and cations) are treat explicitly. Solutions of flexible polyelectrolytes are investigated using the Debye‐Hückel model. The Polymer‐Reference‐Interaction‐Site model for the multicomponent system together with the Reference‐Laria‐Wu‐Chandler closure is solved numerically. It is show that the Coulomb interaction leads to a long‐range liquid like structure. Addition of salt causes screening of the interaction and the structure disappears at very high salt concentrations. Comparison of the correlation functions of the multicomponent systems with those obtained by a one‐component Debye‐Hückel model exhibits good agreement. Moreover, for an appropriate range of parameters, such as density or Bjerrum length, a shell of equally charged saltions exists in the vicinity of a polyion. The effective potential between two monomers displays attraction among the equally charged polyions. The strength of the attraction increases with increasing salt concentration.
Adsorption of linear and star‐shaped polyelectrolytes to monolayers of charged amphiphiles
Authors: Schnitter M. , Menzel H. 
Published: May 2004

AbstractAdsorption of polyelectrolytes has been studied employing monolayers of ionic amphiphiles at the air water interface as model surfaces. The adsorption of polyelectrolytes from a solution brought into contact with the amphiphile monolayer results in changes of the monolayer structure and properties. Monitoring these changes can be done by recording the changes in surface pressure. The kinetics of the adsorption depends strongly on the nature of the polyelectrolyte. Depending on the structure of the polyelectrolyte a purely diffusion controlled adsorption or a sequence of diffusion controlled adsorption and ordering processes have been identified to determine the kinetics. The influence of the molecular architecture on the polyelectrolyte adsorption has been further studied employing linear and star shaped poly(acrylic acid) and poly(N‐propyl‐4‐vinyl pyridinium bromides), respectively. An unexpected behavior with an induction period in the adsorption kinetics of both polymers has been found. Furthermore, the degree of branching has only very minor effects on the adsorption kinetics.
Microsurgical lip replantation: Evaluation of functional and aesthetic results of three cases
Authors: Duroure F. , Simon E. , Fadhul S. , Fyad J.P. , Chassagne J.F. , Stricker M. 
Published: May 2004

AbstractLip amputations are rare, and microsurgical replantation must be systematically tried to restore form and function in one step. The authors present a series of three cases. Revascularization of the amputated segment was obtained by arterial anastomosis with the corresponding labial coronary artery. No venous anastomosis was carried out, because no vein could be identified. Venous drainage was obtained by inducing bleeding and by postoperative application of leeches for 6 days. Anticoagulant therapy and antibiotherapy were used for 10 days. With this approach, two lip amputations were completely saved, and a third amputation only suffered partial necrosis. Aesthetic and functional results were evaluated as being good, with reestablishment of labial continence and recovery of protective sensitivity. © 2004 Wiley‐Liss, Inc.
Oberlin's ulnar nerve transfer to the biceps motor nerve in obstetric brachial plexus palsy: Indications, and good and bad results
Authors: Noaman Hassan Hamdy , Shiha Anis Elsayed , Bahm Jörg 
Published: May 2004

AbstractWe present 7 children with obstetric brachial plexus palsy treated by transferring two motor fascicles out of the ulnar nerve to the biceps nerve. Three were male, and 4 were female. The left‐side brachial plexus was affected in 4 patients, and the right side in 3 patients. All children had vaginal delivery; two of them presented with shoulder dystocia. The average birth weight was 4,300 g (range, 3,620–5,500 g). Average age at time of operation was 16 months (range, 11–24 months). The indication for the operation was absent active elbow flexion with active shoulder abduction against gravity in 4 cases, and no biceps function and bad shoulder function in 3 cases. Oberlin's ulnar nerve transfer was done in 4 cases without brachial plexus exploration in those children with good shoulder function, and exploration of the brachial plexus was performed in the other 3 cases with bad shoulder function. The average follow‐up was 19 months (range, 13–30 months). Five children had biceps muscle ≥M3 with active elbow flexion against gravity, and 2 children had biceps muscle <M3. We recommend Oberlin's ulnar nerve transfer for upper‐type obstetric brachial plexus palsy in 1) breech delivery with avulsion of C5 and C6 nerve roots,) late presentation with good recovery of shoulder function, and 3) neuroma‐in‐continuity of the upper trunk with intraoperative good nerve conduction for the shoulder muscles, the same as preoperative good shoulder function but with no biceps action. © 2004 Wiley‐Liss, Inc.
Singularities of the resolvent at the thresholds of a stratified operator: a general method
Authors: Gado Bio Soumarou Chabi , Durand Marc , Goudjo Côme 
Published: May 2004

AbstractOur problem is about propagation of waves in stratified strips. The operators are quite general, a typical example being a coupled elasto‐acoustic operator H defined in ℝ2 × I where I is a bounded interval of ℝ with coefficients depending only on z∈I. One applies the ‘conjugate operator method’ to an operator obtained by a spectral decomposition of the partial Fourier transform Ĥ of H. Around each value of the spectrum (except the eigenvalues) including the thresholds, a conjugate operator may be constructed which ensures the ‘good properties’ of regularity for H. A limiting absorption principle is then obtained for a large class of operators at every point of the spectrum (except eigenvalues). If the point is a threshold, the limiting absorption principle is valid in a closed subspace of the usual one (namely L, with s>½) and we are interested by the behaviour of R(z), z close to a threshold, applying in the usual space L, with s>½ when z tends to the threshold. Copyright © 2004 John Wiley & Sons, Ltd.
Differential protonation and dynamic structure of doxylamine succinate in solution using 1H and 13C NMR
Authors: Somashekar B. S. , Nagana Gowda G. A. , Ramesha A. R. , Khetrapal C. L. 
Published: May 2004

AbstractA protonation and dynamic structural study of doxylamine succinate, a 1:1 salt of succinic acid with dimethyl‐[2‐(1‐phenyl‐1‐pyridin‐2‐yl‐ethoxy)ethyl]amine, in solution using one‐ and two‐dimensional 1H and 13C NMR experiments at variable temperature and concentration is presented. The two acidic protons of the salt doxylamine succinate are in ‘intermediate’ exchange at room temperature, as evidenced by the appearance of a broad signal. This signal evolves into two distinct signals below about −30 °C. A two‐dimensional 1H1H double quantum filtered correlation experiment carried out at −55 °C shows protonation of one of the acidic protons to the dimethylamine nitrogen. A two‐dimensional rotating frame 1H1H NOE experiment at the same temperature reveals that the other proton remains with the succinate moiety. Comparison of the 1H and 13C chemical shifts and the 13C T1 relaxation times of the salt with those of the free base further substantiate the findings. Copyright © 2004 John Wiley & Sons, Ltd.
Complete assignments of 1H and 13C NMR data for 10 phenylethanoid glycosides
Authors: Wu Jun , Huang Jianshe , Xiao Qiang , Zhang Si , Xiao Zhihui , Li Qingxin , Long Lijuan , Huang Liangmin 
Published: May 2004

AbstractTen phenylethanoid glycosides, including two new ones, isolated from the aerial parts of the mangrove plant Acanthus ilicifolius were identified. The first complete assignments of the 1H and 13C NMR chemical shifts for these glycosides were achieved by means of 2D NMR techniques, including 1H–1H COSY, TOCSY, HSQC and HMBC spectra. Copyright © 2004 John Wiley & Sons, Ltd.
Automated structure elucidation of two unexpected products in a reaction of an α,β‐unsaturated pyruvate
Authors: Sharman Gary J. , Jones Ian C. , Parnell Mark P. , Willis Michael C. , Mahon Mary F. , Carlson Dean V. , Williams Antony , Elyashberg Mikhail , Blinov Kirill , Molodtsov Sergey G. 
Published: May 2004

AbstractThe reaction between an α,β‐unsaturated pyruvate and ethyl diazoacetate (EDA) yielded two unexpected products. The structures of these products were determined by automated elucidation of the chemical structures using spectroscopic inputs of a series of 1D and 2D NMR data using the computer program ACD/Structure Elucidator, StrucEluc. The formation of these products is rationalised. Their structures were also confirmed by x‐ray crystallography. Copyright © 2004 John Wiley & Sons, Ltd.
Complete NMR elucidation of a novel trishomocubane hydantoin and its mono‐ and bis‐t‐Boc protected derivatives
Authors: Fourie Louis , Govender Thavendran , Hariprakasha Humcha K. , Kruger Hendrik G. , Raasch Terrence 
Published: May 2004

AbstractThe syntheses of a novel trishomocubane hydantoin and its mono‐ and bis‐protected t‐Boc derivatives are described. The less nucleophilic N‐3′ nitrogen of the hydantoin ring is protected first when treated with di‐tert‐butyl dicarbonate (t‐Boc anhydride), possibly owing to steric hindrance by the bulky trishomocubane cage skeleton. More basic conditions were required to form the bis‐protected t‐Boc hydantoin with the same reagent. The structures of these novel compounds were elucidated with 2D NMR techniques. The proton spectrum of the trishomocubane skeleton is complex owing to major overlap of proton signals. A high‐level DFT calculation was used to determine some of the crucial interatomic positions, which assisted with the elucidation of the structures. The assignment of proton and carbon signals of the three structures is described and it differs significantly from each other and also from the trishomocubanol precursor. The bis‐Boc hydantoin is required for a more facile hydrolysis to the corresponding trishomocubane amino acid at room temperature. Copyright © 2004 John Wiley & Sons, Ltd.
Opportunities afforded by the study of unmyelinated nerves in skin and other organs
Authors: Kennedy William R. 
Published: May 2004

AbstractNeurological practice is mainly focused on signs and symptoms of disorders that involve functions governed by myelinated nerves. Functions controlled by unmyelinated nerve fibers have necessarily remained in the background because of the inability to consistently stain, image, or construct clinically applicable neurophysiological tests of these nerves. The situation has changed with the introduction of immunohistochemical methods and confocal microscopy into clinical medicine, as these provide clear images of thin unmyelinated nerves in most organs. One obvious sign of change is the increasing number of reports from several laboratories of the pathological alterations of cutaneous nerves in skin biopsies from patients with a variety of clinical conditions. This study reviews recent methods to stain and image unmyelinated nerves as well as the use of these methods for diagnosing peripheral neuropathy, for experimental studies of denervation and reinnervation in human subjects, and for demonstrating the vast array of unmyelinated nerves in internal organs. The new ability to examine the great variety of nerves in different organs opens opportunities and creates challenges and responsibilities for neurologists and neuroscientists. Muscle Nerve 756–767, 2004
Beak gape dynamics during song in the zebra finch
Authors: Goller Franz , Mallinckrodt Mary Jo , Torti Sylvia D. 
Published: May 2004

AbstractBird song is a complex communication behavior that requires the coordination of several motor systems. Sound is produced in the syrinx and then modified by the upper vocal tract, but the specific nature and dynamics of this modification are not well understood. To determine the contribution of beak movements to sound modification, we studied the beak gape patterns in zebra finches (Taeniopygia guttata). Subsyringeal air sac pressure and song were recorded together with changes in beak gape, which were monitored with a magneto‐sensitive transducer. Beak gape was positively correlated with fundamental frequency, peak frequency, and subsyringeal air sac pressure in all but one bird. For harmonic stacks, peak frequency increased with increasing beak gape, and the relationship between fundamental frequency and beak gape was no longer significant. Experimentally holding the beak open or closed had acoustic consequences consistent with the model in which beak movements change upper vocal tract length and, thus, the filter properties. Beak gape was positively correlated with sound amplitude in all but two birds. The relationship between beak aperture and amplitude may, however, be indirect because air sac pressure is correlated with amplitude and beak gape. The beak is opened quickly and to its widest aperture immediately prior to the onset of sound and at rapid transitions in sound, suggesting that beak movements may affect vibratory behavior of the labia. © 2004 Wiley Periodicals, Inc. J Neurobiol 59: 289–303, 2004
Global formulation of 3D magnetostatics using flux and gauged potentials
Authors: Repetto M. , Trevisan F. 
Published: May 2004

AbstractThe use of algebraic formulation for the solution of electromagnetic fields is becoming more and more widespread. This paper presents the theoretical development of two algebraic formulations of the magneto‐static problem and their implementation in a three dimensional computational procedure based on an unstructured tetrahedral mesh. A complete description of the variables used and of the solution algorithm is provided together with a discussion about the performances of the method. The performances of the two procedures are tested and assessed versus cases with known solutions. Copyright © 2004 John Wiley & Sons, Ltd.
Switching between multivariable controllers
Authors: Niemann Henrik , Stoustrup Jakob , Abrahamsen Rune B. 
Published: May 2004

AbstractA concept for implementation of multivariable controllers is presented in this paper. The concept is based on the Youla–Jabr–Bongiorno–Kucera (YJBK) parameterization of all stabilizing controllers. Using this scheme for implementation of multivariable controllers, it is shown how it is possible to smoothly switch between multivariable controllers with guaranteed closed‐loop stability. This includes also the case where one or more controllers are unstable.The concept for smooth on‐line changes of multivariable controllers based on the YJBK architecture can also handle the start‐up and shut down of multivariable systems. Furthermore, the start‐up of unstable multivariable controllers can be handled as well. Finally, implementation of (unstable) controllers as a stableQparameter in aQ‐parameterized controller can also be achieved. Copyright © 2004 John Wiley & Sons, Ltd.
Organ distribution of severe acute respiratory syndrome (SARS) associated coronavirus (SARS‐CoV) in SARS patients: implications for pathogenesis and virus transmission pathways
Authors: Ding Yanqing , He Li , Zhang Qingling , Huang Zhongxi , Che Xiaoyan , Hou Jinlin , Wang Huijun , Shen Hong , Qiu Liwen , Li Zhuguo , Geng Jian , Cai Junjie , Han Huixia , Li Xin , Kang Wei , Weng Desheng , Liang Ping , Jiang Shibo 
Published: May 2004

AbstractWe previously identified the major pathological changes in the respiratory and immune systems of patients who died of severe acute respiratory syndrome (SARS) but gained little information on the organ distribution of SARS‐associated coronavirus (SARS‐CoV). In the present study, we used a murine monoclonal antibody specific for SARS‐CoV nucleoprotein, and probes specific for a SARS‐CoV RNA polymerase gene fragment, for immunohistochemistry and in situ hybridization, respectively, to detect SARS‐CoV systematically in tissues from patients who died of SARS. SARS‐CoV was found in lung, trachea/bronchus, stomach, small intestine, distal convoluted renal tubule, sweat gland, parathyroid, pituitary, pancreas, adrenal gland, liver and cerebrum, but was not detected in oesophagus, spleen, lymph node, bone marrow, heart, aorta, cerebellum, thyroid, testis, ovary, uterus or muscle. These results suggest that, in addition to the respiratory system, the gastrointestinal tract and other organs with detectable SARS‐CoV may also be targets of SARS‐CoV infection. The pathological changes in these organs may be caused directly by the cytopathic effect mediated by local replication of the SARS‐CoV; or indirectly as a result of systemic responses to respiratory failure or the harmful immune response induced by viral infection. In addition to viral spread through a respiratory route, SARS‐CoV in the intestinal tract, kidney and sweat glands may be excreted via faeces, urine and sweat, thereby leading to virus transmission. This study provides important information for understanding the pathogenesis of SARS‐CoV infection and sheds light on possible virus transmission pathways. This data will be useful for designing new strategies for prevention and treatment of SARS. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
A multistep model for ovarian tumorigenesis: the value of mutation analysis in the KRAS and BRAF genes
Authors: Russell S. E. Hilary , McCluggage W. Glenn 
Published: May 2004

AbstractEpithelial ovarian tumours represent a complex group of histological subtypes and there has long been controversy over the question of a precursor lesion for these neoplasms. The application of mutation analysis of the KRAS and BRAF genes (members of the RAS‐RAF‐MEK‐ERK‐MAP kinase pathway) is consistent with the model for progression of mucinous carcinomas and a subset of serous carcinomas (the so‐called low‐grade serous carcinomas) through benign and borderline lesions. The relatively high incidence of BRAF and KRAS mutations in serous borderline tumours and low‐grade serous carcinomas, and their extremely low incidence/absence in high‐grade serous carcinomas, provide strong evidence that high‐grade carcinomas do not arise through this intermediate step. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
CK20 expression, CDX2 expression, K‐ras mutation, and goblet cell morphology in a subset of lung adenocarcinomas
Authors: Yatabe Yasushi , Koga Takaomi , Mitsudomi Tetsuya , Takahashi Takashi 
Published: May 2004

AbstractThere are data in the literature that suggest a close relationship between the expression of CK20 and CDX2, K‐ras mutations, and goblet cell morphology. The present study has examined these factors in a cohort of 264 non‐small cell lung cancers. Thirteen of 212 adenocarcinomas expressed CK20; 29 expressed CDX2; K‐ras mutation was identified in 28; and goblet cell features were present in 19. These four factors correlated with each other in a complex way and therefore a logistic regression model was constructed. Significant correlations were found between CK20 and CDX2 expression, and between K‐ras mutation and goblet cell morphology, and there was a marginal correlation between CDX2 immunoreactivity and goblet cell morphology. These four features have also been commonly detected in colorectal, pancreato‐biliary, and ovarian mucinous carcinomas, suggesting that these adenocarcinomas may be prototypical, independent of the organ of origin. Furthermore, as high and uniform expression of CDX2 was characteristic of metastatic colorectal cancer, weak and/or focal CDX2 expression should alert surgical pathologists to the possibility of primary lung adenocarcinoma, especially in the presence of goblet cell morphology. However, some lung adenocarcinomas may express CDX2 strongly: in this case, CK20 also tends to be positive. Copyright © 2004 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.