bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis of Substituted Diazoniapentaphene Salts by an Unexpected Rearrangement‐Cyclodehydration Sequence
Authors: Granzhan Anton , Ihmels Heiko , Mikhlina Katya , Deiseroth Hans‐Jörg , Mikus Holger
Published: August 2005

The cyclodehydration of bis(pyridiniummethyl)methylbenzenes 3a–b in polyphosphoric acid leads to methyl‐substituted diazoniapentaphene salts 4a–b instead of linear diazoniapentacene derivatives, while the 1,3‐bis(pyridiniummethyl)bromobenzene 3d forms a semi‐betaine 4a,12a‐diazoniapentaphen‐14‐olate 4d under these conditions. The mechanistic details of this rearrangement–cyclodehydration sequence may be explained by an intramolecular ipso‐addition to the substituted benzene moiety, followed by an [1,2]‐methyl shift in case of 4a–b or HBr elimination in case of 4d. The proposed mechanism was confirmed by the isolation of the intermediate hydroxy derivative 10b from the cyclization of 3a in refluxing HBr and conversion of 10b to the final product 4a by dehydration in polyphosphoric acid. Electronic absorption and fluorescence properties of the previously unknown diazoniapentaphene salts have been studied. Photophysical properties of 4a–b resemble the ones of the parent diazoniapentaphene salts, while semi‐betaine 4d possesses a red‐shifted absorption and fluorescence maxima, along with significant solvatochromism with respect to the absorption properties. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Value of Two Noninvasive Methods to Detect Progression of Fibrosis Among HCV Carriers With Normal Aminotransferases *
Authors: Colletta Cosimo , Smirne Carlo , Fabris Carlo , Toniutto Pierluigi , Rapetti Rachele , Minisini Rosalba , Pirisi Mario
Published: August 2005

The course of hepatitis C virus (HCV) infection carriers with normal/near-normal aminotransferases (NALT) is usually mild; however, in a few, fibrosis progression occurs. We aimed to verify whether monitoring by liver biopsy might be replaced by noninvasive methods and to identify factors associated with fibrosis progression in patients with persistently normal alanine aminotransferases. We studied 40 untreated HCV-RNA–positive subjects (22 male; median age, 44 years), who underwent two liver biopsies, with a median interval of 78.5 months, during which alanine aminotransferase concentrations (median number of determinations: 12) never exceeded 1.2 times the upper normal limit. Within 9 months from the second biopsy, they were tested by the shear elasticity probe (Fibroscan) and the artificial intelligence algorithm FibroTest. METAVIR fibrosis scores were analyzed in relationship to demographic, clinical, and viral parameters. Weighted kappa analysis was used to verify whether the results of noninvasive methods agreed with histology. Significant fibrosis (≥F2), present at the first biopsy in only one patient (2.5%), was observed at the second biopsy in 14 patients (35%). At multivariate analysis, excess alcohol consumption in the past (>20 g/d;

P

= .017) and viral load (>8.0 × 106 copies/mL;

P

= .021) were independent predictors of progression. In identifying patients with significant fibrosis, inter-rater agreement was excellent for Fibroscan (weighted kappa = 1.0), and poor for FibroTest (weighted kappa = −0.041).
In conclusion
, among HCV carriers with NALT, Fibroscan is superior to the FibroTest in the noninvasive identification of fibrosis, for which excess alcohol consumption in the past and high viral load represent risk factors. (Hepatology 2005.)
Recapitulation of In Vivo Gene Expression During Hepatic Differentiation From Murine Embryonic Stem Cells *
Authors: Yamamoto Yusuke , Teratani Takumi , Yamamoto Hanako , Quinn Gary , Murata Sigenori , Ikeda Rieko , Kinoshita Kenji , Matsubara Kenichi , Kato Takashi , Ochiya Takahiro
Published: August 2005

Hepatic differentiation at the molecular level is poorly understood, mainly because of the lack of a suitable model. Recently, using adherent monoculture conditions, we demonstrated the direct differentiation of hepatocytes from embryonic stem (ES) cells. In this study, we exploited the direct differentiation model to compare the gene expression profiles of ES cell–derived hepatocytes with adult mouse liver using DNA microarray technology. The results showed that the ES cell–derived hepatocyte gene expression pattern is very similar to adult mouse liver. Through further analysis of gene ontology categories for the 232 most radically altered genes, we found that the significant categories related to hepatic function. Furthermore, through the use of small interfering RNA technology

in vitro

, hepatocyte nuclear factor 3β/FoxA2 was identified as having an essential role in hepatic differentiation. These results demonstrate that ES cell–derived hepatocytes recapitulate the gene expression profile of adult mouse liver to a significant degree and indicate that our direct induction system progresses via endoderm differentiation.
In conclusion
, our system closely mimics

in vivo

hepatic differentiation at the transcriptional level and could, therefore, be useful for studying the molecular basis of hepatocyte differentiation

per se.

(Hepatology 2005.)
Susceptibility to Hepatitis A in Patients With Chronic Liver Disease Due to Hepatitis C Virus Infection: Missed Opportunities for Vaccination *
Authors: Shim Michael , Khaykis Inessa , Park James , Bini Edmund J.
Published: August 2005

Hepatitis A virus (HAV) superinfection is associated with a high risk of liver failure and death in patients with underlying chronic liver disease. Although HAV vaccination is recommended for all patients with chronic hepatitis C virus (HCV) infection, little is known about adherence to these recommendations in clinical practice. The aims of this study were to determine the frequency of HAV testing and vaccination among patients with chronic HCV infection. We conducted a retrospective cohort study of 1,193 patients diagnosed with chronic HCV infection over a 1-year period. During 1,646 person-years of follow-up, patients were seen by their primary care provider a median of 10.0 times (interquartile range, 4.0-20.0). HAV antibody testing was performed in 640 subjects (53.6%), and 317 (49.5%) of those tested were susceptible (HAV antibody negative). Only 94 of the 1,193 patients (7.9%) received the HAV vaccine, including 26.8% of the 317 susceptible patients, 0.9% of the 323 patients who were already immune to HAV, and 1.1% of the 553 subjects who were never tested. Among the 94 vaccinated patients, 45 received only one dose of the vaccine. Three of the unvaccinated patients developed acute HAV infection during follow-up, and 1 of them died of acute liver failure.
In conclusion
, despite published recommendations to vaccinate against HAV in patients with chronic HCV infection, we found that HAV testing and vaccination rates were low in clinical practice. Public health programs to increase awareness about HAV vaccination in patients with chronic liver disease are needed. (Hepatology 2005.)
Locally 2‐arc transitive graphs, homogeneous factorizations, and partial linear spaces
Authors: Giudici Michael , Li Cai Heng , Praeger Cheryl E.
Published: August 2005

We establish natural bijections between three different classes of combinatorial objects; namely certain families of locally 2‐arc transitive graphs, partial linear spaces, and homogeneous factorizations of arc‐transitive graphs. Moreover, the bijections intertwine the actions of the relevant automorphism groups. Thus constructions in any of these areas provide examples for the others. © 2005 Wiley Periodicals, Inc. J Combin Designs 14: 139–148, 2006
Molecular pathology and pathogenesis of inclusion‐body myositis
Authors: Askanas Valerie , Engel W. King
Published: August 2005

We summarize the molecular phenotype, diagnostic criteria, and the newest advances related to seeking the pathogenic mechanism(s) of sporadic inclusion‐body myositis (s‐IBM), a muscle disease usually of persons over age 50. On the basis of our research, several processes seem to be important in relation to the still‐speculative pathogenesis: 1) increased transcription and accumulation of amyloid‐β precursor protein (AβPP), and accumulation of its proteolytic fragment Aβ; 2) abnormal accumulation of cholesterol, caveolin‐1, and apolipoprotein E; 3) oxidative stress; 4) accumulations of intramuscle fiber multiprotein aggregates; and 5) evidence that unfolded/misfolded proteins participate in s‐IBM pathogenesis. Our basic hypothesis is that overexpression of AβPP within the aging muscle fibers is an early upstream event causing a subsequent pathogenic cascade. Microsc. Res. Tech. 67:114–120, 2005. © 2005 Wiley‐Liss, Inc.
Evaluating triggers and enhancers of tau fibrillization
Authors: Kuret Jeff , Congdon Erin E. , Li Guibin , Yin Haishan , Yu Xian , Zhong Qi
Published: August 2005

Alzheimer's disease is characterized in part by the aggregation of tau protein into filamentous inclusions. Because tau filaments form in brain regions associated with memory retention, and because their appearance correlates well with the degree of dementia, they have emerged as robust markers of disease progression. Yet the discovery that mutations in tau protein can lead directly to filament and tangle formation in humans, and that filament formation is linked to neurodegeneration in model biological systems, suggests that tau aggregation may also contribute directly to degeneration in affected neurons. In this context, the mechanism of tau filament formation and its modulation by mutation and posttranslational modification is of fundamental importance. Here, recent progress on the molecular mechanisms underlying tau aggregation deduced from in vivo and in vitro experimentation is reviewed and a model rationalizing the effect of posttranslational and other structural modifications on assembly kinetics and thermodynamics is presented. We hypothesize that tau aggregation can be described as a heterogeneous nucleation reaction, where exogenous effectors, tau gene mutations, or other modifications that stabilize assembly‐competent conformations of tau act to trigger the fibrillization reaction. In contrast, those that modulate postnuclear equilibria can enhance fibrillization by increasing the free energy difference between polymers and unincorporated monomers, resulting in stabilization of filaments at low bulk protein concentrations. Microsc. Res. Tech. 67:141–155, 2005. © 2005 Wiley‐Liss, Inc.
Structure and morphology of the Alzheimer's amyloid fibril
Authors: Stromer Thusnelda , Serpell Louise C.
Published: August 2005

Amyloid fibrils are deposited in a number of diseases, including Alzheimer's disease, Type 2 diabetes, and the transmissible spongiform encephalopathies (TSE). These insoluble deposits are formed from normally soluble proteins that assemble to form fibrous aggregates that accumulate in the tissues. Electron microscopy has been used as a tool to examine the structure and morphology of these aggregates from ex vivo materials, but predominantly from synthetic amyloid fibrils assembled from proteins or peptides in vitro. Electron microscopy has shown that the fibrils are straight, unbranching, and are of a similar diameter (60–100 Å) irrespective of the precursor protein. Image processing has enhanced electron micrographs to show that amyloid fibrils appear to be composed of protofilaments wound around one another. In combination with other techniques, including X‐ray fiber diffraction and solid state NMR, electron microscopy has revealed that the internal structure of the amyloid fibril is a ladder of β‐sheet structure arranged in a cross‐β conformation. Microsc. Res. Tech. 67:210–217, 2005. © 2005 Wiley‐Liss, Inc.
Structural insights into Alzheimer filament assembly pathways based on site‐directed mutagenesis and S‐glutathionylation of three‐repeat neuronal Tau protein
Authors: Dinoto Luca , Deture Michael A. , Purich Daniel L.
Published: August 2005

Although Tau and MAP2 readily assemble into straight filaments (SFs), Tau's unique ability to form paired‐helical filaments (PHFs) may offer clues as to why Tau's microtubule‐binding region (MTBR) is the exclusive building block of the neurofibrillary tangles that accumulate during Alzheimer's disease. To learn more about the factors permitting Tau to form both SFs and PHFs, we investigated the microtubule binding, thiol oxidation, and polymerization reactions of the monomer and dimer forms of Tau and MAP2 MTBRs. This review focuses on electron microscopic evidence (1) that facilitated the identification of amino acid residues within 3‐repeat Tau that promote PHF formation; and (2) provided experimental evidence for the polymerization of S‐glutathionylated three‐repeat Tau, a reaction that unambiguously demonstrates that disulfide‐linked Tau‐S‐S‐Tau dimer formation is not a compulsory step in filament assembly. We also consider these findings within the context of current views on the genetic and biochemical basis of Tau fibrillogenesis. Microsc. Res. Tech. 67:156–163, 2005. © 2005 Wiley‐Liss, Inc.
Olfactory metamorphosis in the Coastal Giant Salamander (Dicamptodon tenebrosus)
Authors: Stuelpnagel Jeremy T. , Reiss John O.
Published: August 2005

This study examined the gross morphology and ultrastructure of the olfactory organ of larvae, neotenic adults, and terrestrial adults of the Coastal Giant Salamander (Dicamptodon tenebrosus). The olfactory organ of all aquatic animals (larvae and neotenes) is similar in structure, forming a tube extending from the external naris to the choana. A nonsensory vestibule leads into the main olfactory cavity. The epithelium of the main olfactory cavity is thrown into a series of transverse valleys and ridges, with at least six dorsal and nine ventral valleys lined with olfactory epithelium, and separated by ridges of respiratory epithelium. The ridges enlarge with growth, forming large flaps extending into the lumen in neotenes. The vomeronasal organ is a diverticulum off the ventrolateral side of the main olfactory cavity. In terrestrial animals, by contrast, the vestibule has been lost. The main olfactory cavity has become much broader and dorsoventrally compressed. The prominent transverse ridges are lost, although small diagonal ridges of respiratory epithelium are found in the lateral region of the ventral olfactory epithelium. The posterior and posteromedial wall of the main olfactory cavity is composed of respiratory epithelium, in contrast to the olfactory epithelium found here in aquatic forms. The vomeronasal organ remains similar to that in large larvae, but is now connected to the mouth by a groove that extends back through the choana onto the palate. Bowman's glands are present in the main olfactory cavity at all stages, but are most abundant and best developed in terrestrial adults. They are lacking in the lateral olfactory epithelium of the main olfactory cavity. At the ultrastructural level, in aquatic animals receptor cells of the main olfactory cavity can have cilia, short microvilli, a mix of the two, or long microvilli. Supporting cells are of two types: secretory supporting cells with small, electron‐dense secretory granules, and ciliated supporting cells. Receptor cells of the vomeronasal organ are exclusively microvillar, but supporting cells are secretory or ciliated, as in the main olfactory cavity. After metamorphosis two distinct types of sensory epithelium occur in the main olfactory cavity. The predominant epithelium, covering most of the roof and the medial part of the floor, is characterized by supporting cells with large, electron‐lucent vesicles. The epithelium on the lateral floor of the main olfactory cavity, by contrast, resembles that of aquatic animals. Both types have both microvillar and ciliated receptor cells. No important changes are noted in cell types of the vomeronasal organ after metamorphosis. A literature survey suggests that some features of the metamorphic changes described here are characteristic of all salamanders, while others appear unique to D. tenebrosus. J. Morphol. © 2005 Wiley‐Liss, Inc.
Evaluation of the RF field uniformity of a double‐tuned 31P/1H birdcage RF coil for spin‐echo MRI/MRS of the diabetic foot
Authors: Greenman Robert L. , Rakow‐Penner Rebecca
Published: August 2005

Purpose

To evaluate the B1 field uniformity of a double‐tuned birdcage coil designed for 31P/1H MRI/MRS spin‐echo (SE) imaging of the metatarsal head region of the foot in neuropathic diabetic patients.

Materials and Methods

A low‐pass double‐tuned 31P/1H RF birdcage coil was constructed to fit over the adult forefoot. Flip angle (FA) maps were created from B1 data acquired at the 3T 31P (four normal subjects) and 1H (five normal subjects) frequencies. T2‐weighted (T2‐W) 1H images, 31P rapid acquisition with relaxation enhancement (RARE) images, and composite SE pulse CSI data were acquired to demonstrate the uniformity of the resulting images and data.

Results

The means and standard deviations (SDs) of the range of FAs across the feet of the volunteer subjects indicated good uniformity (the maximum coefficients of variation (CVs) for all of the 31P and 1H FA maps were 7.6% and 7.3%, respectively). The FA values across the metatarsal head region indicated a maximum signal intensity variation of ±3% in a RARE image acquired using an echo train length of 32.

Conclusion

A 31P/1H birdcage coil constructed for MRI/MRS studies of the human forefoot provided sufficient signal uniformity of SE data to facilitate accurate 31P concentration measurements in muscle. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Three‐dimensional contrast‐enhanced steady‐state free precession for improved catheter‐directed coronary magnetic resonance angiography
Authors: Green Jordin D. , Omary Reed A. , Schirf Brian E. , Tang Richard , Carr James C. , Li Debiao
Published: August 2005

Purpose

To demonstrate the feasibility of three‐dimensional thick‐partition, contrast‐enhanced, catheter‐directed coronary artery magnetic resonance angiography (MRA) and test the hypothesis that three‐dimensional imaging improves coronary artery background contrast‐to‐noise ratio (CNR) compared to two‐dimensional imaging.

Materials and Methods

Catheters were advanced into the coronary arteries of swine (N = 6) under MR guidance. Three‐dimensional coronary MRA was performed after intracoronary injection of a small dose of contrast media using magnetization‐prepared steady‐state free precession (SSFP) with two thick partitions. For comparison, two magnetization‐prepared two‐dimensional SSFP scans were also performed, one with no signal averaging and one with two signal averages. All sequences had the same coverage and in‐plane spatial resolution.

Results

The coronary artery was successfully catheterized in all (6/6) animals. CNR for three‐dimensional imaging was 11.1 ± 1.2 for proximal arterial segments and 4.3 ± 0.4 for distal segments. Without averaging, two‐dimensional imaging CNRs for proximal and distal segments were 5.0 ± 0.7 and 1.2 ± 0.2, respectively. With averaging, two‐dimensional imaging CNRs for proximal and distal segments were 9.4 ± 1.5 and 2.9 ± 0.4, respectively. Three‐dimensional imaging showed a statistically significant increase in CNR over all two‐dimensional imaging for both proximal and distal segments (P < 0.05).

Conclusion

Three‐dimensional thick‐partition, contrast‐enhanced, catheter‐directed coronary MRA is feasible and improves CNR over two‐dimensional projection imaging. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Magnetic resonance imaging artifacts caused by aneurysm clips and shunt valves: Dependence on field strength (1.5 and 3 T) and imaging parameters
Authors: Olsrud Johan , Lätt Jimmy , Brockstedt Sara , Romner Bertil , Björkman‐Burtscher Isabella M.
Published: August 2005

Purpose

To evaluate artifact sizes at 3 T compared to at 1.5 T, and to evaluate the influence of scanning parameters with respect to artifact size on a 3‐T magnetic resonance imaging (MRI) system.

Materials and Methods

Two aneurysm clips and five shunt valves were imaged in a water phantom at 1.5 and 3 T. At 3 T the influence of bandwidth (spin echo (SE) images) and echo time (gradient echo (GRE) images) on artifact size (area and extension in two orthogonal directions) was investigated.

Results

Artifact sizes increased substantially (typically 5–10 mm) at 3 T, compared to at 1.5 T, for implants entirely made of metallic materials, whereas the increase was the size less prominent (0–5 mm) for implants only partly containing metal. Artifact areas could be altered by changing the bandwidth or the echo time to about the same extent as it was affected by the increased field strength.

Conclusion

Artifact sizes increase at 3 T, compared to at 1.5 T, depending on the type and composition of the implant, but can be substantially reduced by altering the imaging parameters. Optimization of imaging protocols to minimize artifacts is therefore important at higher field strengths. J. Magn. Reson. Imaging 2005. © 2005 Wiley‐Liss, Inc.
Surgical treatment of extravasation injuries
Authors: Napoli Pietro , Corradino Bartolo , Badalamenti Giuseppe , Tripoli Massimiliano , Vieni Salvatore , Furfaro M. Fabio , Cordova Adriana , Moschella Francesco
Published: August 2005

The authors present their experience of treating anti‐cancer drug extravasation by means of a composite surgical technique that consists of infiltration with physiological solution and hyaluronidase and subsequent manual aspiration of solutes alternated with profuse irrigation of the infiltrated area. In the immediate post‐op we carry out a medical therapy that consists of calciparine and topic antibiotic and/or steroid creams. Since the year 2000 this technique has been used on 25 patients. We have had neither complications nor scars. J. Surg. Oncol. 2005;91:264–268. © 2005 Wiley‐Liss, Inc.
Identification of impurities in acarbose by using an integrated liquid chromatography‐nuclear magnetic resonance and liquid chromatography‐mass spectrometry approach
Authors: Novak Predrag , Cindrić Mario , Tepeš Predrag , Dragojević Snježana , Ilijaš Marina , Mihaljević Krešo
Published: August 2005

The usefulness of applying an integrated LC‐NMR and LC‐MS approach to acarbose bulk drug impurity profiling is demonstrated. LC‐MS and LC‐NMR methodologies were employed for the online separation and structural elucidation of a final drug product. Combining data provided by the stop‐flow LC‐NMR and LC‐MS experiments made it possible to identify the main components present in the acarbose sample. Spectral analysis revealed thatAandBwere known impurities whileCwas an unknown compound. LC‐MS and LC‐NMR analyses revealed thatCwas a pentasaccharide differing from the acarbose in number and nature of sugar subunits in the molecule. It was subsequently isolated and its structure was confirmed by the offline 1‐ and 2‐D NMR experiments, and atom assignment was made.
SPE – Microwave‐assisted extraction coupled system for the extraction of pesticides from water samples
Authors: Mutavdžić Dragana , Horvat Alka J. M. , Babić Sandra , Kaštelan‐Macan Marija
Published: August 2005

SPE is a commonly applied technique for preconcentration of pesticides from water samples. Microwave‐assisted extraction (MAE) technique is the extraction applied for preconcentration of different compounds from solid samples. SPE coupled with MAE is capable of preconcentrating these compounds from water samples too. This investigation was aimed at improving the efficiency of atrazine, alachlor, and α‐cypermethrin pesticide extraction from the spiked water samples applying SPE followed by MAE. In this way, MAE served for elution of pesticides from C18‐extraction disks with solvent heated by microwave energy. Various elution conditions were tested for their effects on the extraction efficiency of the SPE–MAE combined technique. Several parameters, such as elution solvent volume (mL), elution temperature (°C), and duration of elution (min), affect the extraction efficiency of the SPE–MAE coupled system and need to be optimized for the selected pesticides. In order to develop a mathematical model, 15 experiments were performed in the central composite design. The equation was then used to predict recoveries of the pesticides under specific experimental conditions. Optimization of microwave extraction was accomplished using the genetic algorithm approach. Best results were achieved using 20 mL of ethanol at 60°C. Optimal hold time was 5 min and 24 s. The SPE–MAE combination was also compared with the conventional SPE extraction technique with elution of a nonpolar or a moderately polar compound with nonpolar solvents.
Two‐dimensional chromatography as a tool for studying band broadening in size‐exclusion chromatography
Authors: Popovici Simona T. , van der Horst Aschwin , Schoenmakers Peter J.
Published: August 2005

Comprehensive 2‐D size‐exclusion chromatography (SEC×SEC) has been realized. SEC×SEC is not a useful technique for characterizing complex polymers. However, it is potentially an elegant tool to study band‐broadening phenomena. If narrow fractions can be collected from the first dimension, the band broadening in the second dimension is only due to chromatographic dispersion. This would allow a clear distinction to be made between chromatographic band broadening (column and extra‐column) and SEC selectivity (band broadening due to sample polydispersity). In comparison with MALDI‐MS, SEC×SEC allows the study of polymers across a much broader molar‐mass range.
Identification of drying oils in mixtures of natural binding media used for artistic and historic works by capillary electrophoresis
Authors: Harrison Sabine M. , Kaml Isabella , Rainer Florian , Kenndler Ernst
Published: August 2005

To characterise the technologies and to find the appropriate treatments, the identification of the binding media of artistic and historic objects is of high importance for the restorer and conservator. Often applied together with other binders, in the present paper, the applicability of a CZE method was ascertained for the identification of the constituents of drying oils in mixtures with animal glues and/or plant gums. The drying oils are identified after alkaline hydrolysis due to their content of long‐chain saturated and unsaturated fatty acids (palmitic, stearic, oleic, linoleic, linolenic) and shorter‐chain dicarboxylic acids (pimelic, suberic, azelaic, sebacic). The dicarboxylic acids occur as products of the unsaturated acids by oxidative degradation during the drying process. The possible interferences in CE caused by the other binders are amino acids and/or monosaccharides. Such interferences could be expected as indirect UV detection has to be used, which is highly unspecific. It was found that none of the constituents of the animal glues or plant gums migrate in the time window of the analytes, thus not obstructing the identification of the analytes in any of the oil mixtures with one binder, or with a combination of both. No interference is observed even in excess of the glues. The method was applied for the identification of a drying oil in a paint layer from a ceremonial mask originating from Papua New Guinea. There is evidence that the oil is most probably from candlenut tree (Aleurites moluccana).
Effect of surfactant counterion and organic modifier on the properties of surfactant vesicles in electrokinetic chromatography
Authors: Schuster Stephanie A. , Foley Joe P.
Published: August 2005

See original 2005, vol. 28, issue 12, pp. 1399–1408. DOI 10.1002/jssc.200500208
Sleep quality in complicated grief
Authors: Germain Anne , Caroff Krissa , Buysse Daniel J. , Shear M. Katherine
Published: August 2005

The aim of the present study was to evaluate severity of sleep disturbances in a group of 105 individuals presenting with complicated grief (CG) accompanied or not by comorbid depression and/or posttraumatic stress disorder (PTSD). A sample of 105 adults meeting criteria for CG was included in this study. All completed the Pittsburgh Sleep Quality Index (PSQI). The total sample presented a mean global PSQI score of 9.44, indicating overall poor sleep quality. Comorbid depression, but not PTSD, further worsened sleep quality. Further studies are required to investigate the potential role of poor sleep quality as a modifiable risk factor of complicated grief response.
Femtosecond laser spectrochemical analysis of plant samples
Authors: Samek O , Lambert J , Hergenröder R , Liška M , Kaiser J , Novotný K , Kukhlevsky S
Published: August 2005

Using a femtosecond laser-based technique,
spectrochemical analysis of leaf samples is demonstrated. The
study is exemplified for Fe. Standard reference concentrations –
internal standards – of Fe in the two leaf samples were measured
using the method of Relaxation Weighted Magnetic Resonance
Imaging. From the spectra obtained using Laser Induced Breakdown
Spectroscopy technique, spatial distribution of Fe within the leaf
was identified. Thus, this technique could potentially be used as
a complementary technique for identification of storage and
trafficking of iron ions within different plant compartments. In
particular, individual plant cells can be investigated without
collateral damage with high spatial distribution.
Identification problem for a one‐dimensional vibrating system
Authors: Trooshin Igor , Yamamoto Masahiro
Published: August 2005

We discuss an inverse problem of determining a coefficient matrix and an initial value for a one‐dimensional non‐symmetric hyperbolic system of the first order by means of boundary values over a time interval. Provided that a time interval is sufficiently long and a given initial value satisfies some non‐degeneracy condition, we characterize coefficient matrices and initial values realizing the same boundary values. In the case where the initial value is fixed, we can prove the uniqueness in determining all the components of the coefficient matrices. The proof is based on a transformation formula and spectral properties. Copyright © 2005 John Wiley & Sons, Ltd.
New anisotropic models from isotropic solutions
Authors: Maharaj S. D. , Chaisi M.
Published: August 2005

We establish an algorithm that produces a new solution to the Einstein field equations, with an anisotropic matter distribution, from a given seed isotropic solution. The new solution is expressed in terms of integrals of known functions, and the integration can be completed in principle. The applicability of this technique is demonstrated by generating anisotropic isothermal spheres and anisotropic constant density Schwarzschild spheres. Both of these solutions are expressed in closed form in terms of elementary functions, and this facilitates physical analysis. Copyright © 2005 John Wiley & Sons, Ltd.
1H NMR assignment and secondary structure of recombinant RGD‐hirudin
Authors: Liu Xingang , Yan Xiaomin , Mo Wei , Song Houyan , Dai Linsen
Published: August 2005

The conformation of a new recombinant RGD‐hirudin, which has the activities of anti‐thrombin and anti‐platelet aggregation, was investigated by multi‐dimensional NMR spectroscopy. The 1H NMR spectra of this protein are assigned in a sequential manner by using a combination of 2D NMR techniques to demonstrate through‐bond and through‐space (<5 Å) connectivities. The secondary structure of recombinant RGD‐hirudin was deduced from chemical shift indices, sequential NOEs and 3JHNα coupling constants. The results show that the recombinant RGD‐hirudin has two anti‐parallel β‐sheets and no α‐helix, and also that the Arg–Gly–Asp (RGD) binding motif of this protein is located at the end of a long arm, which consists of two anti‐parallel β‐strands (residues 26–31 and 36–41). As the strands are connected by a β‐turn, the recombinant RGD‐hirudin acquires high flexibility and inhibits platelet aggregation more effectively. Copyright © 2005 John Wiley & Sons, Ltd.
Effective elastic properties of the double‐periodically cracked plates
Authors: Wang G. S.
Published: August 2005

In this paper, the interaction of double‐periodical cracks is accurately solved based on the isolating analysis procedure, superposition principle, pseudo‐traction method, Chebyshev polynomial expansion and crack‐surface collocation technique. The jump displacement crossing crack faces, the average additional strain and therefore the effective compliance of the double‐periodically cracked plate are directly determined. The numerical results for axial‐symmetrically distributed double‐periodical cracks, general double‐periodical cracks with one collinear direction as well as two sets of double‐periodical cracks with same size and square distribution are given in this paper. And the partial typical numerical results are compared with the previous works. The analysis shows that the anisotropy induced by the general double‐periodical cracks is generally not orthogonal anisotropy. Only when the double‐periodical cracks are axial‐symmetrically distributed, is the anisotropy orthogonal. In this special cases, the effective engineering constants (consist of effective elastic modulus, the effective Poisson's ratio, the effective shear modulus) of cracked plate versus crack spacing, in the plane stress and plane strain conditions, respectively, are analysed. Copyright © 2005 John Wiley & Sons, Ltd.
Optimal harvesting in an integrodifference population model
Authors: Joshi Hem Raj , Lenhart Suzanne , Gaff Holly
Published: August 2005

We consider the harvest of a certain proportion of a population that is modelled by an integrodifference equation. This model is discrete in time and continuous in the space variable. The dispersal of the population is modelled by an integral of the population density against a kernel function. The control is the harvest, and the goal is to maximize the profit. The optimal control is characterized by introducing an adjoint function. This paper gives the first optimal control result in integrodifference equations. Numerical results and interpretations are given for four different kernels. Copyright © 2005 John Wiley & Sons, Ltd.
Structural and functional characterization of a 5,10‐methenyltetrahydrofolate synthetase from Mycoplasma pneumoniae (GI: 13508087)
Authors: Chen Shengfeng , Yakunin Alexander F. , Proudfoot Michael , Kim Rosalind , Kim Sung‐Hou
Published: August 2005

Mycoplasma pneumoniae 5,10‐methenyltetrahydrofolate synthetase [MTHFS; also known as 5‐formyltetrahydrofolate cycloligase; Enzyme Commission (EC) 6.3.3.2] belongs to a large cycloligase protein family with 97 sequence homologues from bacteria to human. To help define the molecular (biochemical and biophysical) function of the M. pneumoniae MTHFS, we have previously determined its crystal structure at 2.2 Å resolution (Chen et al., Proteins 2004;56:839–843). In this current study, activity assays confirmed the functionality of the recombinant protein, with Km = 165 μM for 5‐formyltetrahydrofolate (5‐FTHF) and Km = 166 μM for MgATP. The methenyltetrahydrofolate activity of M. pneumoniae MTHFS has a requirement for divalent metal ions with Mg2+ being most effective, and an absolute requirement for nucleoside 5′‐triphosphates with adenosine triphosphate (ATP) being most effective. Crystallization in the presence of substrates (MgATP, with or without 5‐FTHF) produced the complex structures of the protein with adenosine diphosphate (ADP) and phosphate at 2.2 Å resolution; with ADP, phosphate, and 5‐FTHF at 2.5 Å resolution. These structures directly demonstrated that the role of Mg2+ in the reaction is to form the ATPMg2+–enzyme complex. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Structures of vertebrate hyaluronidases and their unique enzymatic mechanism of hydrolysis
Authors: Jedrzejas Mark J. , Stern Robert
Published: August 2005

Human hyaluronidases (Hyals) are a group of five endo‐β‐acetyl‐hexosaminidase enzymes, Hyal‐1, ‐2, ‐3, ‐4, and PH‐20, which degrade hyaluronan using a hydrolytic mechanism of action. Catalysis by these Hyals has been shown to follow a double‐displacement scheme. This involves a single Glu residue within the enzyme, the only catalytic residue, as the proton donor (acid). Also involved is a carbonyl group of the hyaluronan (HA) N‐acetyl‐D‐glucosamine as a unique type of nucleophile. Thus the substrate participates in the mechanism of action of its own catalysis. An oxocarbonium ion transition state is postulated, but there is no formation of a covalent enzyme–glycan intermediate, as found in most such reactions. The major domain is catalytic and has a distorted (β/α)8 triose phosphate isomerase (TIM) barrel fold. The C‐terminal domain is separated by a peptide linker. Each Hyal has a different C‐terminal sequence and structure, the function of which is unknown. These unique C‐termini may participate in the additional function(s) associated with these multifunctional enzymes. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Does secondary structure determine tertiary structure in proteins?
Authors: Gong Haipeng , Rose George D.
Published: August 2005

Is highly approximate knowledge of a protein's backbone structure sufficient to successfully identify its family, superfamily, and tertiary fold? To explore this question, backbone dihedral angles were extracted from the known three‐dimensional structure of 2,439 proteins and mapped into 36 labeled, 60° × 60° bins, called mesostates. Using this coarse‐grained mapping, protein conformation can be approximated by a linear sequence of mesostates. These linear strings can then be aligned and assessed by conventional sequence‐comparison methods. We report that the mesostate sequence is sufficient to recognize a protein's family, superfamily, and fold with good fidelity. Proteins 2005. © 2005 Wiley‐Liss, Inc.
Small peptides, big world: biotechnological potential in neglected bioactive peptides from arthropod venoms
Authors: Pimenta Adriano M. C. , De Lima Maria Elena
Published: August 2005

Until recently, a toxinologist's tasks involved the search for highly toxic or lethal toxins in animal venoms that could explain the harmful effects in clinically observed symptoms. Most of these toxins were put on evidence using a function to structure approach, in which a biological phenomena observation usually guided the isolation and characterization of the causative molecule. Paving this way, many toxins were promptly purified because of their readily observed effect. Nevertheless, small molecules with micro‐effects that are not easily visualized can be relatively neglected or poorly studied. This situation has changed now with the advent of the sensitivity, resolution and accuracy of techniques such as mass spectrometry and proteomic approaches used in toxinology. Taking advantage of these methodologies, small peptides with ‘newly exploited’ biological activities such as vasoactive, hormone‐like, antimicrobial and others have been recently given much more attention, enlarging the known repertoire of bioactive molecules found in animal venoms. This article aims to review current knowledge on small biologically active peptides (<3 kDa) found in arthropod venoms and discuss their potentialities as new drug candidates or therapeutic lead compounds. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
Function and therapeutic potential of host defence peptides
Authors: Mcphee Joseph B. , Hancock Robert E. W.
Published: August 2005

Cationic host defence (antimicrobial) peptides are an important component of the innate immune systems of a wide variety of plants, animals, and bacteria. Although most of these compounds have direct antimicrobial activities under specific conditions, a greater appreciation for the diversity of functions of these molecules is beginning to develop in the field. In addition to their directly antimicrobial activities, they also have a broad spectrum of activity on the host immune system, with both pro‐inflammatory and anti‐inflammatory effects being invoked. Increasingly sophisticated approaches to understand the role of host defence peptides in modulating innate immunity are already serving to guide the development of novel therapeutics. Copyright © 2005 European Peptide Society and John Wiley & Sons, Ltd.
Temperature evolution of the local order parameter in relaxor ferroelectrics (1 – x)PMN–xPZT
Authors: Gridnev S. A. , Glazunov A. A. , Tsotsorin A. N.
Published: August 2005

The temperature dependence of the local order parameter and relaxation time distribution function have been determined in (1 – x)PMN–xPZT ceramic samples via dielectric permittivity. Above the Burns temperature, the permittivity was found to follow the Currie–Weiss law, and with temperature decreasing the deviation was observed to increase. A local order parameter was calculated from the dielectric data using a modified Landau–Devonshire approach. These results are compared to the distribution function of relaxation times. It was found that a glasslike freezing of reorientable polar clusters occurs in the temperature range of diffuse relaxor transition. The evolution of the studied system to more ordered state arises from the increased PZT content. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Ultra‐low energy SIMS study of ultra‐shallow boron implants in HPHT diamond
Authors: Guzmán de la Mata B. , Dowsett M. G. , Palitsin V.
Published: August 2005

The primary beam energy and species (Cs+, Ar+) dependence of ultra low energy SIMS depth profiles of ultra‐shallow boron implants into CVD grown diamond is investigated in this paper. The data are compared with TRIM simulation of the 5 keV 11B+ implant. Cs+ profiles (1 keV, 30°) appear to be seriously distorted by atomic mixing and recoil implantation due to the high mass of the probe. Ar+ profiles (300 eV–1 keV, 0°) are less distorted, but both Cs+ and Ar+ tend to produce significant tails. The Ar+ SIMS profiles produce implants which appear to be shallower than the TRIM simulation. We show that profiling using Ar+ with energies between 0.3 and 1 keV can be used to extrapolate a profile to zero beam energy. The extrapolated data indicate a centroid between 5 and 10 nm from the surface, whereas TRIM predicts 11 nm. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Matrix rounding with respect to small submatrices
Authors: Doerr Benjamin
Published: August 2005

We show that any real valued matrix A can be rounded to an integer one B such that the error in all 2 × 2 (geometric) submatrices is less than 1.5, that is, we have |aij − bij| < 1 and $|\sum_{k = i}^{i+1}\sum_{\ell = j}^{j+1} (a_{k\ell} - b_{k\ell})| < 1.5$ for all i,j. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2006
XPS studies of octadecylphosphonic acid (OPA) monolayer interactions with some metal and mineral surfaces
Authors: McIntyre N. S. , Nie H. ‐ Y. , Grosvenor A. P. , Davidson R. D. , Briggs D.
Published: August 2005

Partial and complete self‐assembled monolayers (SAMs) of octadecylphosphonic acid (OPA) have been deposited onto air‐exposed surfaces of the metals copper, silver, gold, iron, silicon and aluminium, as well as onto freshly cleaved, air‐exposed surfaces of the minerals muscovite and biotite. The line width of the C(1s) signal in the XPS spectra of the surface narrowed, as the extent of coverage increased to 100%, to a half‐width of 0.9 eV. Moreover, the line widths associated with the insulating muscovite substrate also became substantially narrower as OPA coverage increased. Binding energy differences on this charge‐shifted surface were found to be more consistent when OPA was used as a charge reference, compared to using adventitious carbon as a reference. OPA coverage of the air‐exposed metals copper, silver, gold and iron also produced narrow C(1s) spectra whose binding energies were consistently close to 284.9 eV. The C(1s) binding energy positions on Al and Si samples were charge‐shifted by the insulating nature of the thin oxide formed on air exposure, or by the insulating nature of the substrate in the case of the minerals. Correction of the observed C(1s) energy position to 284.9 eV gave sets of elemental binding energies for the substrate materials that were reproducible. Thus, OPA coverage could be a possible alternative candidate for use in charge correction of binding energies of insulating materials. The OPA coverage cases were modelled using the software QUASES™ Analyse. For the substrates copper, silver, gold, iron and aluminium, analyses of the metal core line spectra gave OPA overlayer thicknesses close to those measured by AFM (1.6 nm). However, QUASES™ analyses of the C(1s) extrinsic backgrounds for the same surfaces required the use of an attenuation length of only 0.4 nm to derive a comparable thickness—much lower than literature values for carbon. This discrepancy is ascribed to the structured nature of the SAM. Copyright © 2005 John Wiley & Sons, Ltd.
Phylogenetic inference and comparative evolution of a complex microsatellite and its flanking regions in carnivores
Authors: DOMINGO-ROURA XAVIER , LÓPEZ-GIRÁLDEZ FRANCESC , SAEKI MIDORI , MARMI JOSEP
Published: August 2005

We sequenced locus Mel08, with complex short repetitive motifs, in 24 carnivore species belonging to five different families in order to explore mutational changes in the region in the context of locus and species evolution. This non-coding locus includes up to four different parts or repetitive motifs showing size variability. The variability consists of repeat additions and deletions; substitutions, insertions and/or deletions creating interruptions in the repeat; and substitutions, insertions and deletions in the flanking regions. The locus has different repeat expansions in different carnivore subfamilies. We hypothesize that the complexity of this locus is due to a high mutation rate at an ancestral DNA sequence and, thus, prompts the emergence of repeats at mutational hotspots. High levels of homoplasy were evident, with nine electromorphs representing 28 haplotypes never shared across species. The variability in flanking regions was informative for phylogenetic inference and their evolutionary content. Tree topologies were congruent with relevant hypotheses on current conflicts in carnivore phylogenies, such as: (i) the monophyly of Lutrinae, (ii) the paraphyly of Mustelinae, (iii) the basal position of the Eurasian badger, Meles meles, in the Mustelidae, (iv) the classification of skunks as a separate family, Mephitidae, and (v) the placement of the red panda, Ailurus fulgens, as a monotypic family, Ailuridae, at a basal position in the Musteloidea.
Effect of genes, social experience, and their interaction on the courtship behaviour of transgenic Drosophila males
Authors: SVETEC NICOLAS , HOUOT BENJAMIN , FERVEUR JEAN-FRANÇOIS
Published: August 2005

Behaviour depends (a) on genes that specify the neural and non-neural elements involved in the perception of and responses to sensory stimuli and (b) on experience that can modulate the fine development of these elements. We exposed transgenic and control Drosophila melanogaster males, and their hybrids, to male siblings during adult development and measured the contribution of genes and of experience to their courtship behaviour. The transgene CheB42a specifically targets male gustatory sensillae and alters the perception of male inhibitory pheromones which leads to frequent male–male interactions. The age at which social experience occurred and the genotype of tester males induced a variable effect on the intensity of male homo- and heterosexual courtship. The strong interaction between the effects of genes and of social experience reveals the plasticity of the apparently stereotyped elements involved in male courtship behaviour. Finally, a high intensity of homosexual courtship was found only in males that simultaneously carried a mutation in their white gene and the CheB42a transgene.