bluuebunny/crossref_metadata_2025_split huggingface dataset:
Temperature requirements for thermal modulation in comprehensive two‐dimensional gas chromatography
Authors: Gaines Richard B. , Frysinger Glenn S. 
Published: March 2004

AbstractTemperature requirements for trapping and release of compounds in a cryogenic gas loop‐type GC×GC modulator were determined. Maximum trapping temperatures on the uncoated, deactivated modulator capillary were determined for compounds from C4 (bp –0.5°C) to C40 (bp 522°C). The liquid‐nitrogen cooled gas flow rate was reduced from a high of 15.5 to 1.5 SLPM over the range to achieve the required trapping temperature. Excessive cold jet flow rates caused irreversible trapping and peak tailing for semi‐volatile compounds above C26. Alternate cold jet coolants were investigated. An ice water‐cooled jet was able to trap compounds with boiling points from C18 (bp 316°C) to C40 and a room temperature air‐cooled jet was able to trap compounds from C20 (bp 344°C) to C40. The hot jet produced launch temperatures approximately 40°C hotter than the elution temperature with heating time constants of 8 to 27 ms. Modulated compound peaks were symmetrical with half‐height peak widths of 43 to 56 ms for compounds with little second column retention, and 70 to 75 ms for compounds with more second column retention. The liquid nitrogen‐cooled loop modulator with gas flow programming was used to produce a GC×GC chromatogram for a crude oil that contained compounds from C7 to C47.
Application of comprehensive multidimensional gas chromatography combined with time‐of‐flight mass spectrometry (GC×GC‐TOFMS) for high resolution analysis of hop essential oil
Authors: Roberts Mark T. , Dufour Jean‐Pierre , Lewis Alastair C. 
Published: March 2004

AbstractThe selection and quality of hops is a major determinant in beer flavour. Brewers acknowledge that distinctive characteristics of different hop varieties can be traced to the composition of their essential oils. The difficulty in characterising complex mixtures such as hop oil using 1‐D chromatography is that many compounds co‐elute. With the introduction of comprehensive multidimensional capillary gas chromatography (GC×GC), there is a tremendous improvement in the separation power or peak capacity. Recent work using GC×GC with flame ionisation detection has suggested that there may be over 1,000 compounds in hop oil. This work describes the use of GC×GC combined with TOFMS detection (Leco Pegasus 4D instrument) to analyse Target hop oil. The TOFMS spectral acquisition rate of 60 Hz provided sufficient spectra per peak (2‐D peak base width of 0.1–0.2 s) for identification (119 components were identified with 45 previously unreported compounds). When analysing results, an advantage of GC×GC coupled to TOFMS is that 2‐D chromatograms can be viewed for individual masses that are characteristic of particular functional groups. This allows the analyst to view the various homologous series of compounds although in certain cases coelution may still be present as shown by the esters with mass 75.
Comprehensive two‐dimensional gas chromatography in the analysis of dietary fatty acids
Authors: Hyötyläinen Tuulia , Kallio Minna , Lehtonen Mari , Lintonen Stella , Peräjoki Päivi , Jussila Matti , Riekkola Marja‐Liisa 
Published: March 2004

AbstractComprehensive two‐dimensional gas chromatography utilising a semi‐rotating cryogenic modulator was applied to the analysis of dietary milk derived fatty acids. Four column combinations were tested: two polar‐nonpolar and two different nonpolar‐polar column combinations. Best results were obtained with a nonpolar‐polar column set, with narrow‐bore (50 μm ID) Carbowax column as the second column. The GC×GC method clearly improved the separation efficiency of the fatty acids in comparison with one‐dimensional GC analysis and proved to be suitable for the quantification of the analytes. The relative standard deviations (RSD) of the retention times in the first and second dimensions were on average 0.06% and 4.9%, respectively. The relative RSD for peak volumes was on average 2.9%.
Comonomer‐Unit Compositions, Physical Properties and Biodegradability of Bacterial Copolyhydroxyalkanoates
Authors: Feng Lidan , Yoshie Naoko , Asakawa Naoki , Inoue Yoshio 
Published: March 2004

AbstractSummary: The comonomer‐unit compositions and their distribution of as‐produced bacterial copolyesters, including poly(3‐hydroxybutyrate‐co‐3‐hydroxyvalerate), poly(3‐hydroxy‐butyrate‐co‐3‐hydroxypropionate), poly(3‐hydroxybutyrate‐co‐3‐hydroxyhexanoate) and poly(3‐hydroxybutyrate‐co‐4‐hydroxybutyrate) are described in this paper. Each copolyester sample can be comonomer‐unit compositionally fractionated into several fractions, indicating that the original copolymers are mixtures of copolymers with different comonomer‐unit compositions. The effects of comonomer‐unit compositional distribution on thermal properties, crystallization, biodegradability and solid‐state phase behavior are investigated using comonomer compositionally fractionated copolymers.The trend shown by the Tm values of the copolymers, P(3HB‐co‐3HV), P(3HB‐co‐3HP), P(3HB‐co‐3HH) and P(3HB‐co‐4HB), plotted against the content of the second monomer unit.imageThe trend shown by the Tm values of the copolymers, P(3HB‐co‐3HV), P(3HB‐co‐3HP), P(3HB‐co‐3HH) and P(3HB‐co‐4HB), plotted against the content of the second monomer unit.
Structure and Structural Changes of the Silk Fibroin from Samia cynthia ricini Using Nuclear Magnetic Resonance Spectroscopy
Authors: Asakura Tetsuo , Nakazawa Yasumoto 
Published: March 2004

AbstractSummary: The structure of silk fibroin from a wild silkworm, S. c. ricini, the amino acid sequence of which consists of repeated poly‐Ala and Gly‐rich regions, was examined by using solution and solid‐state NMR methods. The structural transition of the silk fibroin in aqueous solution was monitored by using 13C solution NMR spectroscopy as a function of temperature. The fast exchange with respect to the chemical shift between the helix and coil conformations was observed in the poly‐Ala region and the slow conformational change from α‐helix to random coil was observed for the Gly residue adjacent to the N‐terminal Ala residue of the poly‐Ala region. The torsion angles of several Ala and Gly residues in the model peptide, GGAGGGYGGDGG(A)12GGA‐GDGYGAG, were determined by the conformation‐dependent 13C chemical shifts, rotational echo double resonance (REDOR) and 2D spin‐diffusion NMR methods. The solid‐state NMR analysis leads to the precise silk structure before spinning, where the poly‐Ala sequence takes a typical α‐helix pattern with a tightly winded helical structure at both terminal regions of the poly‐Ala sequence. This is expected to stabilize the α‐helical structure of the poly‐Ala region in S. c. ricini silk fibroin from the silkworm.The proposed helical structure of poly(L‐alanine) region of S. c. ricini silk fibroin before spinning.imageThe proposed helical structure of poly(L‐alanine) region of S. c. ricini silk fibroin before spinning.
Degradable Polyesters through Chain Linking for Packaging and Biomedical Applications
Authors: Seppälä Jukka V. , Helminen Antti O. , Korhonen Harri 
Published: March 2004

AbstractSummary: The major route to convert lactic acid to high‐molecular‐weight polymers is ring‐opening polymerization of lactide. We have investigated alternative synthesis routes based on oligomerization and chain linking to produce high‐molecular‐weight thermoplastic degradable polymers cost‐effectively. Chain linking also offers new possibilities to prepare degradable polyesters for biomedical applications by extending the range of polymer properties achievable. In this paper, we briefly review different chain linking techniques used in our laboratory. Typically, lactic acid prepolymers with molecular weights of around 3 000–15 000 g · mol−1 have been prepared by direct polycondensation. Hydroxyl terminated oligomers have been chain linked by using diisocyanate coupling agents, preferably 1,4‐butane diisocyanate, forming poly(ester‐urethanes). Poly(ester‐amides) have been prepared by using 2,2′‐bis(2‐oxazoline) as coupling agent for carboxylic acid telechelic oligomers. Chain linking by end functionalization has been used in the preparation of poly(ester‐anhydrides). In addition, a variety of crosslinked degradable polymers and copolymers have been synthesized through different crosslinking routes, by using methacrylic, itaconic or maleic double bonds or triethoxysilane moieties. A biodegradation test and ecotoxicological evaluation of the degradation products were carried out in addition to hydrolysis tests. Lactic acid based chain linked polymers were biodegradable and the degradation products were harmless. In hydrolysis tests, enzymatic degradation was pronounced in the chain linked poly(ε‐caprolactone).image
Application of proteomics technologies in the investigation of the brain
Authors: Fountoulakis Michael 
Published: March 2004

Abstract

I.
Introduction
232

II.
Proteomic Analysis
233

A.  Sample Preparation
233

B.  Two‐Dimensional (2‐D) Electrophoresis
234

C.  Protein Quantification
235

D.  Mass Spectrometry (MS)
236

1.  Matrix‐Assisted Laser Desorption/Ionization Time‐of‐Flight Mass Spectroscopy (MALDI‐TOF‐MS)
236

2.  Tandem MS
237

III.
2‐D Brain Protein Databases
238

A.  Database Construction
238

B.  Subcellular Location
240

C.  Frequency of Detection
240

D.  Protein Function
242

IV.
Alterations in the Protein Levels
243

A.  Adult Brain
243

B.  Fetal Brain
245

V.
Proteomic Studies on Rat Brain
245

A.  Differences Between Neonatal and Adult Brain
245

B.  Post‐Mortem Changes
248

C.  Toxicology Studies
248

VI.
Limitations
248

A.  Brain Samples
248

B.  Protein Detection in 2‐D Gels
249

1.  Low‐Abundance Proteins
249

2.  Hydrophobic Proteins
250

3.  Acidic and Basic Proteins
251

4.  Low‐ and High‐Molecular Mass Proteins
251

5.  Protein Heterogeneity
251

C.  Protein Indentification
252

VII.
Perspectives
253

VIII.
Conclusions
253

Acknowledgments
254

References
254

Approximately 30–50% of the genes in mammals are expressed in the nervous system. A differential expression of genes in distinct patterns is necessary for the generation of the large variety of neuronal phenotypes. Proteomic analysis of brain compartments may be useful to understand the complexity, to investigate disorders of the central nervous system, and to search for corresponding early markers. Up to now, proteomics has mainly studied the identity and levels of the abundant human, rat, and mouse brain proteins as well as changes of their levels and the modifications that result from various neurological disorders, like Alzheimer's disease and Down's syndrome in humans and in animal models of those diseases. The proteins, for which altered levels in these disorders have been observed, exert mainly neurotransmission, guidance, and signal‐transduction functions, or are involved in detoxification, metabolism, and conformational changes. Some of those proteins may be potential drug targets. Further improvement of proteomics technologies to increase sensitivity and efficiency of detection of certain protein classes is necessary for a more detailed analysis of the brain proteome. In this review, a description of the proteomics technologies applied in the investigation of the brain, the major findings that resulted from their application, and the potential and limitations of the current technologies are discussed. © 2004 Wiley Periodicals, Inc., Mass Spec Rev 23:231–258, 2004
INK4a‐ARF mutations in skin carcinomas from UV irradiated hairless mice
Authors: Soufir N. , Queille S. , Mollier K. , Roux E. , Sarasin A. , de Gruijl F.R. , Fourtanier A.M. , Daya‐Grosjean L. , Basset‐Seguin N. 
Published: March 2004

AbstractTo characterize further the role of the INK4a‐ARF locus in the multistep process of skin carcinogenesis, we performed a mutational analysis of this locus in skin lesions from hairless mice either irradiated with UVB alone or with a solar simulator delivering UVA + B. INK4a‐ARF mutations were present in five of 57 squamous cell carcinomas (9%), but no mutation was detected in precancerous lesions. All mutations were C:G > T:A transitions located at dipyrimidic sites, the hallmark of UVB mutagenesis. Three mutations affected only the p19ARF reading frame, whereas two mutations affected only the p16INK4a transcript. This study demonstrates for the first time UV‐induced mutations of INK4a‐ARF that occur in a small percentage in late stages skin tumors. © 2004 Wiley‐Liss, Inc.
LyGDI functions in cancer metastasis by anchoring Rho proteins to the cell membrane
Authors: Ota Takahide , Maeda Masayo , Suto Shiho , Tatsuka Masaaki 
Published: March 2004

AbstractRho family GTPases play an important role in a number of processes related to metastasis, and RhoGDP dissociation, inhibitors (RhoGDIs) regulate Rho family proteins. We cloned genomic DNA from colon carcinoma SW480 cells capable of transforming nonmetastatic ras‐transformed 1‐1ras1000 cells into metastatic cells. This DNA contained a truncated human ras homolog gene family GDP dissociation inhibitor beta (ARHGDIB) gene, resulting in a C‐terminal truncated form of LyGDI (ΔC‐LyGDI, 166–201 deletion), a member of the RhoGDIs. The stable expression of ΔC‐LyGDI induced pulmonary metastasis in 1‐1ras1000 cells, whereas expression of full‐length LyGDI did not induce metastasis. ΔC‐LyGDI was preferentially localized in the membrane, detected in a NP‐40‐insoluble fraction, and co‐purified with radixin, moesin, Rac1, Cdc42, and RhoA. In ΔC‐LyGDI transfectant, an activation state of Rac1 was elevated and ΔC‐LyGDI was associated with Rac1‐GTP. In keeping with the observed localization of Rac1 to the cell membrane and the elevated level of Rac1‐GTP, ΔC‐LyGDI transfectants were found to be more invasive than mock transfectant. These results suggest that LyGDI functions in the cell membrane to afford spatial regulation of Rho family GTPase signaling through ezrin radixin moesin (ERM) proteins during metastasis. © 2004 Wiley‐Liss, Inc.
Advances in molecular carcinogenesis: current and future use of mouse models to screen and validate molecularly targeted anticancer drugs
Authors: Frijhoff Anita F.W. , Conti Claudio J. , Senderowicz Adrian M. 
Published: March 2004

AbstractSurvival of patients with advanced solid tumors has not significantly improved over the past 30 years. Although molecularly targeted anticancer drugs offer promise, few drugs make it through the end of the Food and Drug Administration approval process. Animal models that more closely resemble human carcinogenesis may bridge the gap between preclinical success and benefits for patients. We discuss pros and cons of several mouse models, including genetically engineered mice that each represent different aspects of human cancer, and the screening of targeted drugs in these models. Published 2004 Wiley‐Liss, Inc.
Chediak‐Higashi syndrome with parkinsonism
Authors: Silveira‐Moriyama Laura , Moriyama Tais S. , Gabbi Tatiana V.B. , Ranvaud Ronald , Barbosa Egberto R. 
Published: March 2004

AbstractChediak‐Higashi syndrome (CHS), typically presents with partial albinism and severe hematological abnormalities. About 10% of the patients have a mild adult form associated with various neurological manifestations. We describe the case of a 24‐year‐old woman with parkinsonism that responded well to antiparkinsonian drugs. © 2003 Movement Disorder Society
Imaging of activated microglia with PET and [11C]PK 11195 in corticobasal degeneration
Authors: Henkel Karsten , Karitzky Jochen , Schmid Michaela , Mader Irina , Glatting Gerhard , Unger Jürgen W. , Neumaier Bernd , Ludolph Albert C. , Reske Sven N. , Landwehrmeyer G. Bernhard 
Published: March 2004

AbstractPositron emission tomography (PET) using [11C]PK 11195, a ligand for peripheral benzodiazepine receptor binding sites, offers the opportunity to image activated microglia in vivo. This tool may therefore be used to display the occurrence of microglial activation in the course of neurodegeneration. A patient with the clinical diagnosis of corticobasal degeneration (CBD) and left‐sided symptoms was studied using fluorodeoxyglucose (FDG) and [11C]PK 11195 PET. We found a marked right hemispheric hypometabolism and asymmetric microglial activation in corresponding areas of the basal ganglia and right temporal and parietal cortex. [11C]PK 11195 PET suggests involvement of microglial activation in the pathogenesis of CBD. © 2004 Movement Disorder Society
Punding in Parkinson's disease: Its relation to the dopamine dysregulation syndrome
Authors: Evans Andrew H. , Katzenschlager Regina , Paviour Dominic , O'Sullivan John D. , Appel Silke , Lawrence Andrew D. , Lees Andrew J. 
Published: March 2004

AbstractPunding is a term that was coined originally to describe complex prolonged, purposeless, and stereotyped behaviour in chronic amphetamine users. A structured interview of 50 patients with higher dopamine replacement therapy requirements (>800 levodopa equivalent units/day) from 123 unselected patients with Parkinson's disease (PD) from a PD clinic identified 17 (14%) patients with punding. Punding was acknowledged as disruptive and unproductive by the patients themselves, but forcible attempts by family to interrupt the behaviour led to irritability and dysphoria. Punding was associated with very high doses of dopamine replacement therapy often related to a pattern of chronic inappropriate overuse of dopaminergic medication. We believe that this is an underreported, socially disabling phenomenon that is commonly associated with the syndrome of dopamine dysregulation and is phenomenologically distinct from both obsessive‐compulsive disorder and mania. © 2004 Movement Disorder Society
Chorea‐acanthocytosis associated with tourettism
Authors: Saiki Shinji , Hirose Genjiro , Sakai Koichiro , Matsunari Ichiro , Higashi Kotaro , Saiki Misuzu , Kataoka Satoshi , Hori Ariyuki , Shimazaki Kohei 
Published: March 2004

AbstractWe report on a case of Chorea‐acanthocytosis (ChAc) in association with Tourettism that consisted of motor and vocal tics, attention deficit–hyperactivity disorder, and obsessive–compulsive disorder in addition to the typical symptoms of ChAc. The subject was compared with his elder sister who had the same disease but milder clinical profile and neuroradiological findings. The [18F]‐2‐fluoro‐2‐deoxyglucose positron emission tomography (FDG‐PET) findings did not explain the differences in symptomatology between the patient and his sister, although they may have correlated with severity. © 2004 Movement Disorder Society
Assessing comorbidity in patients with Parkinson's disease
Authors: Visser Martine , Marinus Johan , van Hilten Jacobus J. , Schipper Ruth G.B. , Stiggelbout Anne M. 
Published: March 2004

AbstractThe aim of this study was to assess the accuracy of an interview‐based assessment of comorbidity, in patients with Parkinson's disease (PD). The Cumulative Illness Rating Scale‐Geriatric (CIRS‐G) was completed (1) in an interview with 31 PD patients and their caregivers, and (2) by reviewing the patient's medical charts from their general practitioners. Based on the interview, all patients had some comorbidity, 84% had one or more moderate comorbid diseases. The most frequently affected organ systems were “lower gastrointestinal” and “genitourinary”. The mean ± SD total score of the interview‐based (chart‐based) CIRS‐G was 6.9 ± 3.8 (7.6 ± 3.5) with a mean of 4.3 ± 1.9 (5.0 ± 1.9) affected organ systems and a mean of 2.1 ± 1.7 (2.3 ± 1.6) organ systems with at least moderate comorbidity per patient. The agreement (intraclass correlation coefficients) between the interview‐based and chart‐based assessments for the six summary scores ranged from 0.69 to 0.81. The agreement for the 14 organ systems ranged from 0.13 to 1.00 (weighted kappa); 12 had a Kw above 0.40 (moderate agreement). The comorbidity summary scores had a moderate correlation with age and disability. The interview‐based assessment of the CIRS‐G is easy to apply and is an accurate method to assess comorbidity in patients with PD. © 2004 Movement Disorder Society
Compound sensory action potential in normal and pathological human nerves
Authors: Krarup Christian 
Published: March 2004

AbstractThe compound sensory nerve action potential (SNAP) is the result of phase summation and cancellation of single fiber potentials (SFAPs) with amplitudes that depend on fiber diameter, and the amplitude and shape of the SNAP is determined by the distribution of fiber diameters. Conduction velocities at different conduction distances are determined by summation of SFAPs of varying fiber diameters, and differ in this respect, also, from the compound muscle action potential (CMAP) for which conduction velocities are determined by the very fastest fibers in the nerve. The effect and extent of temporal dispersion over increasing conduction distance is greater for the SNAP than CMAP, and demonstration of conduction block is therefore difficult. In addition, the effect of temporal dispersion on amplitude and shape is strongly dependent on the number of conducting fibers and their distribution, and, with fiber loss or increased conduction velocity variability changes of the SNAP may be smaller than expected from normal nerve. The biophysical characteristics of sensory and motor fibers differ, and this may to some extent determine divergent pathophysiological changes in sensory and motor fibers in different polyneuropathies. In this review, different factors that characterize sensory fibers and set the SNAP apart from the CMAP are discussed to emphasize the supplementary and complementary information that can be obtained from sensory conduction studies. Sensory conduction studies require particular effort and attention to theory and practical detail that may be time consuming. Muscle Nerve 29: 465–483, 2004
Amyloid myopathy presenting with distal atrophic weakness
Authors: Smestad Cathrine , Monstad Per , Lindboe Christian Fredrik , Mygland Åse 
Published: March 2004

AbstractAmyloid myopathy is a rare complication of primary amyloidosis usually presenting with proximal muscle weakness. We report a woman with multiple myeloma in whom marked atrophy and weakness of finger flexor muscles were the first manifestations of systemic amyloidosis. Muscle biopsy revealed amyloid angiopathy with deposits of lambda light chains in vessel walls. The recognition of amyloid myopathy is important because clinical symptoms may respond to chemotherapy. Muscle Nerve 29:605–609, 2004
Modulation of human cervical premotoneurons during bilateral voluntary contraction of upper‐limb muscles
Authors: Stinear James W. , Byblow Winston D. 
Published: March 2004

AbstractA greater proportion of the voluntary command to the affected upper limb of well‐recovered stroke patients descends via the putative C3/4 propriospinal system compared with the unaffected limb or the limbs of control subjects. We have examined whether there are differences in the pattern and extent of the modulation in intact subjects when the upper‐limb muscles are bilaterally activated compared with unilateral activation. Motor evoked potentials (MEPs) recorded from flexor carpi radialis (FCR) in response to transcranial magnetic stimulation (TMS) were assessed for an effect of cocontraction with biceps brachii (BB) and subthreshold electrical conditioning of the musculocutaneous (MC) nerve. No between‐hand differences were revealed, but there was less facilitation during bilateral than unilateral contraction. The findings suggest that the C3/4 propriospinal system is more active during unilateral muscle contraction and less active during bilateral contraction of upper‐limb muscles. Therefore, bimanual rehabilitation strategies for patients with upper‐limb hemiparesis should be developed with caution. Muscle Nerve 29: 506–514, 2004