bluuebunny/crossref_metadata_2025 huggingface dataset:
Ordered Honeycomb‐Structured Films from Dendronized PMA‐b‐PEO Rod‐Coil Block Copolymers
Authors: Cheng Caixia , Tian Ye , Shi Yanqiao , Tang Rupei , Xi Fu
Published: July 2005

Summary: Fabrication of honeycomb‐patterned films from amphiphilic dendronized block copolymer (PEO113‐b‐PDMA82) by ‘on‐solid surface spreading’ and ‘on‐water spreading’ method is reported. Highly ordered honeycomb films with quasi‐horizontally paralleled double‐layered structure can be fabricated by the on‐solid surface spreading method. This work raises the possibility that such structures can be formed in amphiphilic dendronized block copolymers and extends the family of source materials.

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Quantitative 1H NMR method for the routine spectroscopic determination of enantiomeric purity of active pharmaceutical ingredients fenfluramine, sertraline, and paroxetine
Authors: Salsbury Jonathon S. , Isbester Paul K.
Published: July 2005

Determining the enantiomeric purity of chiral therapeutic agents is important in the development of active pharmaceutical ingredients (API). A strategy for determining the enantiomeric purity of three APIs was developed using nuclear magnetic resonance (NMR) and the chiral solvating agent (CSA) 1,1‐bi‐2‐naphthyl (1). While chiral chromatography is widely used to evaluate enantiomeric purity, it can sometimes suffer from tedious sample preparation obviating rapid measurements that are sometimes needed during the manufacture of such agents. The techniques described herein provide comparable enantiomeric purity results with those obtained with traditional chiral HPLC and other published methods for these compounds. Chiral analysis of standard samples of methylbenzylamine enantiomeric mixtures using 1 were found to be quantitative to approximately 1% minor enantiomer. Enantiomeric purity determination by NMR utilizing chiral solvating agents do not require special instrumental techniques, chemical derivatization or standards and is therefore ideally suited for rapid routine analysis. As a result, the technique demonstrated is commonly used in our laboratory as a complementary or alternative method to chiral HPLC or optical rotation measurements for routine determination of enantiomeric purity. Copyright © 2005 John Wiley & Sons, Ltd.
Path‐generation of articulated mechanisms by shape and topology variations in non‐linear truss representation
Authors: Kawamoto A.
Published: July 2005

This paper presents studies on an optimization‐based method for path‐generation of articulated mechanisms. An extended truss ground‐structure approach is taken in which both the shape and topology of the truss are designed using cross‐sectional areas and nodal positions as design variables. This leads to a technique for simultaneous type and dimensional synthesis of articulated mechanisms. For the analysis part it is essential to control the mechanism configuration so that the mechanism remains within a given configuration space, thus stabilizing the optimization process and resulting in realistic solutions. This can be achieved by using the Levenberg–Marquardt method. The design method is illustrated by a number of design cases for both closed and open input and output paths. Copyright © 2005 John Wiley & Sons, Ltd.
HUPO Plasma Proteome Project specimen collection and handling: Towards the standardization of parameters for plasma proteome samples
Authors: Rai Alex J. , Gelfand Craig A. , Haywood Bruce C. , Warunek David J. , Yi Jizu , Schuchard Mark D. , Mehigh Richard J. , Cockrill Steven L. , Scott Graham B. I. , Tammen Harald , Schulz‐Knappe Peter , Speicher David W. , Vitzthum Frank , Haab Brian B. , Siest Gerard , Chan Daniel W.
Published: July 2005

There is a substantial list of pre‐analytical variables that can alter the analysis of blood‐derived samples. We have undertaken studies on some of these issues including choice of sample type, stability during storage, use of protease inhibitors, and clinical standardization. As there is a wide range of sample variables and a broad spectrum of analytical techniques in the HUPO PPP effort, it is not possible to define a single list of pre‐analytical standards for samples or their processing. We present here a compendium of observations, drawing on actual results and sound clinical theories and practices. Based on our data, we find that (1) platelet‐depleted plasma is preferable to serum for certain peptidomic studies; (2) samples should be aliquoted and stored preferably in liquid nitrogen; (3) the addition of protease inhibitors is recommended, but should be incorporated early and used judiciously, as some form non specific protein adducts and others interfere with peptide studies. Further, (4) the diligent tracking of pre‐analytical variables and (5) the use of reference materials for quality control and quality assurance, are recommended. These findings help provide guidance on sample handling issues, with the overall suggestion being to be conscious of all possible pre‐analytical variables as a prerequisite of any proteomic study.
A novel four‐dimensional strategy combining protein and peptide separation methods enables detection of low‐abundance proteins in human plasma and serum proteomes
Authors: Tang Hsin‐Yao , Ali‐Khan Nadeem , Echan Lynn A. , Levenkova Natasha , Rux John J. , Speicher David W.
Published: July 2005

A novel strategy, termed protein array pixelation, is described for comprehensive profiling of human plasma and serum proteomes. This strategy consists of three sequential high‐resolution protein prefractionation methods (major protein depletion, solution isoelectrofocusing, and 1‐DE) followed by nanocapillary RP tryptic peptide separation prior to MS/MS analysis. The analysis generates a 2‐D protein array where each pixel in the array contains a group of proteins with known pI and molecular weight range. Analysis of the HUPO samples using this strategy resulted in 575 and 2890 protein identifications from plasma and serum, respectively, based on HUPO‐approved criteria for high‐confidence protein assignments. Most importantly, a substantial number of low‐abundance proteins (low ng/mL – pg/mL range) were identified. Although larger volumes were used in initial prefractionation steps, the protein identifications were derived from fractions equivalent to approximately 0.6 µL (45 µg) of plasma and 2.4 µL (204 µg) of serum. The time required for analyzing the entire protein array for each sample is comparable to some published shotgun analyses of plasma and serum proteomes. Therefore, protein array pixelation is a highly sensitive method capable of detecting proteins differing in abundance by up to nine orders of magnitude. With further refinement, this method has the potential for even higher capacity and higher throughput.
Centralized data analysis of a large interlaboratory proteomics project: A feasibility study
Authors: Beer Ilan , Barnea Eilon , Admon Arie
Published: July 2005

The human Plasma Proteome Project (PPP) is a large‐scale collaboration between many laboratories. One of the most demanding tasks in the PPP involved the analysis of very large amounts of raw MS/MS data produced by the participants. The main approach for managing this task was letting the participants analyze their own data and submit the results to the central PPP repository as lists of identified proteins and peptides. To complement this distributed approach, we also performed centralized analysis of the raw MS/MS data provided by the participants. Due to the data redundancy inherent in such a project, centralized analysis has the potential to reduce the computational effort by reducing redundancy before the analysis. Centralized analysis can also unify the process and take advantage of data sharing among laboratories to improve protein identification and validation. The process we employed included removing low‐quality spectra, clustering spectra by mutual similarity, and applying uniform peptide and protein identification procedures. To demonstrate the process, we analyzed 5.28 million MS/MS spectra derived by eight laboratories from tryptic peptides of serum and plasma proteins.
Application of 2‐D free‐flow electrophoresis/RP‐HPLC for proteomic analysis of human plasma depleted of multi high‐abundance proteins
Authors: Moritz Robert L. , Clippingdale Andrew B. , Kapp Eugene A. , Eddes James S. , Ji Hong , Gilbert Sam , Connolly Lisa M. , Simpson Richard J.
Published: July 2005

Free‐flow electrophoresis (FFE) and rapid (6 min) RP‐HPLC was used to fractionate human citrate‐treated plasma. Prior to analysis, the six most abundant proteins in plasma were removed by immunoaffinity chromatography; both depleted plasma and the fraction containing the six abundant proteins depleted were taken for MS‐based analysis. Fractionated proteins were digested with trypsin and the generated peptides were subjected to MS‐based peptide sequencing. To date, 78 plasma proteins have been unambiguously identified by manual validation from 16% (15/96 FFE total fractions) of the collected FFE pools; 55 identifications were based on ≥2 tryptic peptides and 23 using single peptides. The molecular weight range of proteins and peptides isolated by this method ranged from ˜190 K (e.g., Complement C3 and C4) to ˜4–6 K (e.g., CRISPP and Apolipoprotein C1). This FFE/RP‐HPLC approach reveals low‐abundance proteins and peptides (e.g., L‐Selectin ˜17 ng/mL and the cancer‐associated SCM‐recognition, immunodefense suppression, and serine protease protection peptide (CRISPP) at ˜0.5–1 ng/mL), where CRISPP was found in association with α‐1‐antitrypsin as a non‐covalent complex, in the fraction containing the depleted high‐abundance proteins. In contrast to shotgun proteomic approaches, the FFE/RP‐HPLC method described here allows the identification of potentially interesting peptides to be traced back to their protein of origin, and for the first time, has confirmed the “protein sponge” hypothesis where the 35 residue CRISPP polypeptide is non‐covalently complexed with the major circulating plasma protein α‐1‐antitrypsin.
Synthesis and properties of a bisphenol A based phthalonitrile resin
Authors: Laskoski Matthew , Dominguez Dawn D. , Keller Teddy M.
Published: July 2005

A multiple aromatic ether linked phthalonitrile was synthesized and characterized. The oligomeric phthalonitrile monomer was prepared from the reaction of an excess amount of bisphenol A with 4,4′‐difluorobenzophenone in the presence of K2CO3 as the base in an N,N‐dimethylformamide/toluene solvent mixture, followed by end capping with 4‐nitrophthalonitrile in a two‐step, one‐pot reaction. The monomer properties were compared to those of the known resin 2,2‐bis[4‐(3,4‐dicyanophenoxy)phenyl]propane after being cured in the presence of bis[4‐(4‐aminophenoxy)phenyl]sulfone. Rheometric measurements and thermogravimetric analysis showed that the oligomeric phthalonitrile resin maintained good structural integrity upon heating to elevated temperatures and exhibited excellent thermal properties along with long‐term oxidative stability. The ether‐linked phthalonitrile resin absorbed less than 2.5% water by weight after exposure to an aqueous environment for extended periods. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 4136–4143, 2005
Studies on the properties of polypropylene with a new silicon‐containing intumescent flame retardant
Authors: Li Qiang , Jiang Pingkai , Wei Ping
Published: July 2005

A new intumescent flame retardant (PSiNII), which contains silicon, phosphorus, and nitrogen elements, has been synthesized and incorporated into polypropylene (PP). Its effect on the properties of PP is investigated based on flame retardancy, thermal properties, mechanical properties, and morphologies. The flame retardancy is evaluated by the limiting oxygen index value. The thermal properties (oxidative behaviors and thermal stability) are investigated by thermogravimetric analysis under nitrogen and air atmosphere. The mechanical properties are researched based on the maximum tensile stress and relative strain at break. The morphologies of PP/PSiNII are studied by the scanning electron micrograph. Their flame retardancy and thermal stability are improved by introducing PSiNII. PP/PSiNII blends can achieve high fire performance and keep high mechanical property at the same time. During a fire, the melt‐dripping behaviors of PP‐containing PSiNII are improved. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 2548–2556, 2005
Heterogeneous distribution of shear strains in deformed Ti66.1Cu8Ni4.8Sn7.2Nb13.9 nanostructure‐dendrite composite
Authors: Kim K. B. , Das J. , Baier F. , Eckert J.
Published: July 2005

Microstructural investigation of a deformed Ti66.1Cu8Ni4.8Sn7.2Nb13.9 nanostructure‐dendrite composite using transmission electron microscopy (TEM) reveals heterogeneous propagation and interaction of the shear bands, depending on the geometry of the interfaces between the nanostructured matrix and dendrites. The geometrical effect on the propagation and interaction of the shear bands is presented by the different morphology of the interfaces i.e. stepped and smooth interfaces suggesting a different amount of accumulated shear strains at the interfaces between the nanostructured matrix and the dendrites. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Prediction of the X‐ray absorption near edge structure of the new high‐density phase of SiO2
Authors: Ching W. Y. , Ouyang Lizhi , Rulis Paul , Tanaka Isao
Published: July 2005

The X‐ray absorption near edge structure (XANES) of the newly predicted high density phase of SiO2 has been calculated using a state‐of‐the‐art supercell method including the core‐hole effect. It is shown that the spectra are unique and have little resemblance to those of low density α‐quartz and high density stishovite. It is demonstrated that the interpretation of XANES based purely on the coordination shell argument is oversimplified. Crystal symmetry and effects beyond the second nearest neighbour must be taken into consideration. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Identification of phospholipid structures in human blood by direct‐injection quadrupole‐linear ion‐trap mass spectrometry
Authors: Wang Chang , Yang Jun , Gao Peng , Lu Xin , Xu Guowang
Published: July 2005

Direct‐injection electrospray ionization mass spectrometry in combination with information‐dependent data acquisition (IDA), using a triple‐quadrupole/linear ion trap combination, allows high‐throughput qualitative analysis of complex phospholipid species from child whole blood. In the IDA experiments, scans to detect specific head groups (precursor ion or neutral loss scans) were used as survey scans to detect phospholipid classes. An enhanced resolution scan was then used to confirm the mass assignments, and the enhanced product ion scan was implemented as a dependent scan to determine the composition of each phospholipid class. These survey and dependent scans were performed sequentially and repeated for the entire duration of analysis, thus providing the maximum information from a single injection. In this way, 50 different phospholipids belonging to the phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, phosphatidylcholine and sphingomyelin classes were identified in child whole blood. Copyright © 2005 John Wiley & Sons, Ltd.
Das dicke Ende: Quantifizierung Operationeller Risiken mit Hilfe des Loss‐Distribution‐Approaches
Authors: Nguyen Minh‐Tri , Ottmann Martin
Published: July 2005

Mit Basel II wurden neben Vorschriften für Markt‐ und Kreditrisiko zum ersten Mal auch Richtlinien für das Management des Operationellen Risikos in den Banken festgesetzt. Zur Berechnung des entsprechenden Eigenkapitals schlug Basel drei Methoden vor: den Basisindikatoransatz (BIA), den Standardansatz (STA) und die fortgeschrittenen Messansätze (AMA). Je komplexer eine Methode ist, desto risiko‐sensitiver ist sie und dadurch sollte sie die Kapitalanforderung einer Bank ihrem Risiko‐Gehalt entsprechend abdecken. Im weiteren Sinne würden die fortgeschrittenen Messansätzen das Risiko‐Kapital einer Bank am meisten reduzieren. Im vorliegenden Artikel besprechen wir den Loss Distribution Approach (LDA). Dieser Ansatz wird seit geraumer Zeit in der Versicherungswirtschaft angewendet und ist auch in der Bankenindustrie weit verbreitet. Dabei geht es hauptsächlich um die Modellierung der Verlustverteilung, die Grundlage für den “Verlustverteilungsansatz”. Durch die Monte‐Carlo‐Simulation der Verlustverteilung ermitteln wir dann den Value‐at‐Risk (VaR), der das Eigenkapital für das Operationelle Risiko bestimmt.
Ein Unternehmen ist kein perfektes Räderwerk
Authors: Weber Jürgen
Published: July 2005

Risikomanagement und Controlling lassen sich kaum mehr scharf voneinander abgrenzen. Auf dem 30. Congress der Controller des Internationalen Controllervereins (ICV) sprachen wir mit Prof. Dr. Jürgen Weber über die Zukunft des Controllings und Controllers sowie über aktuelle Entwicklungen an den Schnittstellen dieser beiden Funktionen.
Calcitonin gene-related peptide and islet amyloid polypeptide stimulate insulin secretion in RINm5F cells through a common receptor coupled to a generation of cAMP
Authors: Barakat A. , Skoglund G. , Boissard C. , Rosselin G. , Marie J.-C.
Published: July 2005

The question as to whether the homologous peptides CGRP and IAPP can regulate insulin secretion in RINm5F cells was addressed. Chicken CGRP displayed a reproducible inhibitory effect on insulin secretion within 0.1 and 1 nM concentrations and a stimulatory effect at higher concentrations. The maximal stimulatory effects on insulin secretion were obtained with 1.0 μM of chicken CGRP (cCGRP), human α-CGRP (h α-CGRP) and human IAPP (hIAPP) which caused 246 ± 22, 302 ± 63 and 224 ± 14 percent increases of control levels, respectively (p < 0.001). Similarly, maximal accumulations of cAMP were obtained with 1.0 μM of cCGRP, h α-CGRP and hIAPP with the respective percent increases of control levels of 587 ± 24, 436 ± 41 and 410 ± 25 (p < 0.005). Thus the stimulatory effects on insulin secretion in RINm5F cells by cCGRP, h α-CGRP and hIAPP appear to be mediated by the cAMP pathway. Chicken CGRP, the most potent peptide tested, displayed a correlated dose response stimulation of intracellular cAMP and insulin release within the concentration range of 10–1000nM. The EC50 values of cCGRP for cAMP accumulation and insulin release were similar (20nM and 10 nM respectively). The stimulatory effect of IAPP on cAMP was not additive with that of cCGRP suggesting that IAPP action was mediated by CGRP receptors. This hypothesis was further sustained by a preferential inhibition of125I[His]h α-CGRP binding to RINm5F cells by cCGRP as compared to IAPP.

We conclude that CGRP and IAPP, through a direct action on a chicken CGRP preferring receptor present in β cells, stimulated insulin by a cAMP mediated pathway.
Immunocytochemical verification of the insulin receptor's specificity in the nuclear envelope of Tetrahymena. Comparison with receptors of the plasma membrane
Authors: Csaba G. , Hegyesi Hargita
Published: July 2005

The unicellular Tetrahymena possess hormone receptors in the nuclear envelope similarly to higher rank animals. These receptors bind insulin and their specificity is detectable by monoclonal antibodies developed to insulin. The hormonal (insulin) pretreatment (imprinting) of the cell did not alter the binding capacity of the nuclear membrane, demonstrated by antibody-technique. The specific binding characteristics of the plasma membrane was demonstrated and this was significantly increased following imprinting. In the nucleus of Tetrahymena presence of insulin was not detected by immunocytochemical method.
Fusion of influenza to liposomes is not inhibited by aliphatic primary alcohols
Authors: Lemay Christian T. Y. , Ceccarelli Derek F. J. , Epand Richard M.
Published: July 2005

Reports of the antiviral activity of aliphatic alcohols led us to investigate the effects of aliphatic alcohols, from 10 to 20 carbons in length, on the phase transition behaviour of model phospholipids and on the fusion of influenza to liposomes. Contrary to the effects of many other antiviral agents, we find that alcohols are potent promoters of the inverted hexagonal phase. However, we also find that aliphatic alcohols have little effect on influenza fusion to liposomes. Eicosanol is the only aliphatic alcohol tested which substantially increases in fusion of influenza virus. We also find that long chain alcohols display multi-component bilayer to hexagonal phase transitions at higher mole fractions. This suggests that eicosanol may be facilitating fusion by creating defects between alcohol-rich and alcohol-poor regions of the lipid bilayer.
10‐year follow‐up of chronic non‐malignant pain patients: Opioid use, health related quality of life and health care utilization
Authors: Jensen Marianne K. , Thomsen Annemarie B. , Højsted Jette
Published: July 2005

BackgroundIn Denmark, opioids have been used liberally for many years in the treatment of non‐malignant pain, but long‐term consequences as tolerance and influence on health related quality of life remain unknown.

AimAdherence to medical treatment, opioid dose escalation, health related quality of life, anxiety, depression, coping strategies and health care utilization were evaluated in chronic pain patients 10 years after treatment in a multidisciplinary pain centre.

MethodsInformation was gathered from medical records, postal questionnaires and a central hospital register.

ResultsOpioid dose escalation occurred in only a few patients. Increase and decrease in opioid dose were almost equally frequent. Sixty percent of those discharged on long acting opioids were still on that treatment at follow‐up. Twenty‐eight percent of the patients initiated opioid treatment after discharge from the pain centre. Occupational status was identified as a determining factor for future opioid use. Opioid users had a lower health related quality of life, higher occurrence of depression and more frequent use of coping strategies like ‘Catastrophizing’ and ‘Hoping and Praying'. Adjuvant analgesics were highly discontinued. Multidisciplinary pain treatment reduced the number of hospital admissions and in‐hospital days.

ConclusionWe recommend that future research on opioid treatment does not only focus on biological issues. The effect of opioids needs to be viewed in a much more complex context where consequences like health related quality of life, depression and the role of various coping strategies are included.
Volume conductor effects involved in the genesis of the P wave
Authors: van Dam Peter M. , van Oosterom Adriaan
Published: July 2005

Aim

To assess the effect of inhomogeneities in the conductivity of different tissues, such as blood and lung tissue, on the body surface potentials generated by atrial electrical activity.

Methods

A 64-lead ECG from a healthy subject was recorded. The subject's geometries of torso, lungs, heart, and blood cavities were derived by magnetic resonance imaging. These geometries were used to construct a numerical volume conductor model. The boundary element method was applied to simulate the potentials on the surface of the thorax generated by the atria. The equivalent double layer served as the source description during depolarization. Recorded body surface potentials were used as a check on the simulations. Subsequently, the conductivities in the model were varied to determine their influence on P wave morphology and amplitude.

Results

The model with realistic conductivity values for blood and lungs produced potentials that closely matched the measured ones (correlation 98%). The subsequent variation of conductivity of blood and lungs revealed a major influence on P wave morphology and amplitude: a mean reduction in amplitude by 42%, with pronounced inter-lead differences.

Conclusion

The inhomogeneities of lungs and atrial blood cavities need to be incorporated in volume conductor models linking atrial electric activity to body surface potentials.
Anatomy of the inferior interatrial route in humans
Authors: Mitrofanova Lubov , Ivanov Vitaly , Platonov Pyotr G.
Published: July 2005

Aims

To explore the morphology of the proximal coronary sinus (CS) and the surrounding tissues in order to identify possible routes for interatrial conduction.

Method

Specimens containing interatrial septum and proximal CS were taken from 21 necropsied hearts and sliced into 10-μm thick parallel histological sections in 1-mm steps starting from the valve plane, up to the atrial roof (40–80 sections per heart). The sections were stained with van Gieson's stain.

Results

Media in the proximal CS consists of smooth muscle cells that do not form a continuous layer. CS was not surrounded by striated atrial myocardium in 10 specimens in which posterior CS wall was covered by epicardial fat only. In seven specimens, striated muscle bundles of up to 2-mm width connected the myocardium surrounding the CS with the left atrium. Regardless of their presence, variable posterior and/or anterior interatrial muscular connections were identified in all specimens.

Conclusion

Variability of the striated atrial myocardium surrounding proximal CS may affect interatrial conduction. Striated muscular fascicles connecting the proximal CS with the left atrium are not obligatory cardiac structures and may be considered as supplementary to the larger interatrial connections outside the CS.
Modelling of short QT syndrome in a heterogeneous model of the human ventricular wall
Authors: Weiss Daniel L. , Seemann Gunnar , Sachse Frank B. , Dössel Olaf
Published: July 2005

Aims

A percentage of sudden cardiac death events occur in individuals with structurally normal hearts due to an abnormality in the ion channel activity. While the majority of these hereditary syndromes are well-established, little is known about the significance of the short QT syndrome.

Methods

This study is based on discovered insights into the molecular basis of the originally described form of this disease. A biophysically detailed model of cellular electrophysiology was adapted to emulate the behaviour of cells affected by the short QT syndrome. Simulations were performed in single cell and homogeneous as well as heterogeneous anisotropic multi-cellular environment describing the human left ventricle.

Results

The short QT mutation increased the activity of the repolarizing outward potassium current IKr. The heterogeneous abbreviation of the action potential duration decreased the dispersion of repolarization in heterogeneous tissue. Repolarization was homogenized and the final repolarization was shifted to epicardial sites. The transmural ECG showed a shortened QT interval and a T wave with reduced amplitude.

Conclusion

The altered characteristics of the mutant IKr current were consistent with experimental findings. The heterogeneous reduction of the action potential duration and the reduced T wave amplitude need to be verified by measurements.
Can orthogonal lead indicators of propensity to atrial fibrillation be accurately assessed from the 12-lead ECG?
Authors: Carlson Jonas , Havmöller Rasmus , Herreros Alberto , Platonov Pyotr , Johansson Rolf , Olsson Bertil
Published: July 2005

Aims

When analyzing P-wave morphology, the vectorcardiogram (VCG) has been shown useful to identify indicators of propensity to atrial fibrillation (AF). Since VCG is rarely used in the clinical routine, we wanted to investigate if these indicators could be accurately determined in VCG derived from standard 12-lead ECG (dVCG).

Methods

ECG and VCG recordings from 21 healthy subjects and 20 patients with a history of AF were studied. dVCG was calculated from ECG using the inverse Dower transform. Following signal averaging of P-waves, comparisons were made between VCG and dVCG, where three parameters characterizing signal shape and 15 parameters describing the P-wave morphology were used to assess the compatibility of the two recording techniques. The latter parameters were also used to compare the healthy and the AF groups.

Results

After transformation, P-wave shape was convincingly preserved. P-wave morphology parameters were consistent within the respective groups when comparing VCG and dVCG, with better preservation observed in the healthy group.

Conclusion

VCG derived from routine 12-lead ECG may be a useful alternate method for studying orthogonal P-wave morphology.
The influence of spatio-temporal egg production variability on the modelled survival of the early life history stages of mackerel (Scomber scombrus) in the eastern North Atlantic
Authors: Bartsch Joachim
Published: July 2005

An individual-based model (IBM) that simulates the transport, growth, and mortality of mackerel (Scomber scombrus) eggs and larvae, is used to determine the modelled survival of mackerel post-larvae in the eastern North Atlantic. Larval and post-larval growth is modelled as a function of length, temperature, and food distribution; mortality is modelled as a function of length and absolute growth rate. Simulations have previously been carried out for the years 1998, 1999, and 2000, in all cases using the same 1998 initial egg distribution as the input field. In the present contribution, the effects of varying the input field are examined by comparing simulations for 1998 and 2001 using initial egg distributions for 1998 and 2001, respectively, and also for a 2001 simulation using the 1998 egg data as input. Results showed that, for the first two cases, the estimated number of survivors for the years 1998 and 2001 was similar, although total egg production (i.e. the magnitude of the input field) in 2001 was only ∼65% of that during 1998. The higher relative survival rate in 2001 results from differences in the timing of peak production, which was 5 weeks later in 2001 than in 1998, and also from greater overall food availability in 2001. Modelling survival for 2001 using 1998 egg data as the initial input field “wrongly” increases survival by 60% compared with using actual 2001 egg data for initialization. This is mainly a function of the increased egg production in 1998 compared with 2001.
Temporal evolution of sediment supply in Lago Puyehue (Southern Chile) during the last 600 yr and its climatic significance
Authors: Bertrand Sébastien , Boës Xavier , Castiaux Julie , Charlet François , Urrutia Roberto , Espinoza Cristian , Lepoint Gilles , Charlier Bernard , Fagel Nathalie
Published: July 2005

Short-term climate changes in Southern Chile are investigated by a multi-proxy analysis of a 53-cm-long sedimentary sequence selected among eight short cores retrieved in Lago Puyehue (Chile, 40°S). This core contains a 600-yr-long undisturbed record of paleo-precipitation changes. Two measurement methods for sediment density, organic matter and biogenic silica contents are compared and the most appropriate techniques are selected. Together with aluminium and titanium concentrations, grain size and geochemical properties of the organic matter, these proxies are used to demonstrate paleo-precipitation changes around 40°S. Increase of terrigenous particle supply between A.D. 1490 and A.D. 1700 suggests a humid period. Contemporaneously, δ13C data show increasing lake productivity, in response to the high nutrient supply. The A.D. 1700–1900 interval is characterized by a decreasing terrigenous supply and increasing δ13C values, interpreted as a drying period. The magnetic susceptibility signal, reflecting the terrigenous/biogenic ratio, demonstrates that similar variations occur in all the undisturbed sedimentary environments of Lago Puyehue. The A.D. 1490–1700 wet period is associated with the onset of the European Little Ice Age (LIA) and interpreted as its local signature. This work supports the fact that the LIA was a global event, not only restricted to the Northern Hemisphere.
Emergence of multidrug-resistant Salmonella enterica serotype Typhi with decreased ciprofloxacin susceptibility in Bangladesh
Authors: RAHMAN M. , SIDDIQUE A. K. , SHOMA S. , RASHID H. , SALAM M. A. , AHMED Q. S. , NAIR G. B. , BREIMAN R. F.
Published: July 2005

During 1989–2002, we studied the antimicrobial resistance of 3928 blood culture isolates of Salmonella enterica serotype Typhi (S. Typhi) in Dhaka, Bangladesh. Overall 32% (1270) of the strains were multidrug-resistant (MDR, resistant to chloramphenicol, ampicillin and trimethoprim–sulphamethoxazole); first detected in 1990 (rate of 8%), increased in 1994 (44%), declined in 1996 (22%, P<0·01 compared to 1994) and re-emerged in 2001 (36%) and 2002 (42%, P<0·01 compared to 1996). An increased MIC of ciprofloxacin (0·25 μg/ml) indicating decreased susceptibility to ciprofloxacin was detected in 24 (18·2%) out of 132 randomly selected strains during 1990–2002; more frequently in MDR than susceptible strains (46·3% vs. 5·5%, P<0·001), and the proportion of them rose to 47% in 2002 from 8% in 2000 (P<0·01). Ciprofloxacin (5 μg) disk diffusion zone diameters of [les ]24 mm as break-point had 98% sensitivity and 100% specificity when compared with a ciprofloxacin MIC of 0·25 μg/ml as break-point for decreased susceptibility; being a useful and easy screen test. All strains were susceptible to ceftriaxone. The emergence of MDR S. Typhi with decreased ciprofloxacin susceptibility will further complicate the therapy of typhoid fever because of the lack of optimum treatment guidelines.
On the sources of fast and slow solar wind
Authors: Feldman U. , Landi E. , Schwadron N. A.
Published: July 2005

The slow speed solar wind as measured at the Earth orbit and beyond is characterized by its velocity of ≃400 km s−1, by its coronal composition and by its frozen‐in temperature (from carbon charge‐states) of 1.4–1.6 × 106 K. In contrast the fast speed solar wind is characterized by its velocity of ≃750 km s−1, its nearly photospheric composition and its frozen‐in temperature of ≃8 × 105 K. The solar wind is believed to originate very close to the solar surface, but since it is accelerated significantly above the solar surface, its velocity cannot be correlated with remote observations to trace its origin. In contrast, elemental abundances and freeze‐in temperatures can be used as tracers for locating the sources from which the slow and fast solar winds emerge. By comparing remote observations with properties of the solar wind observed in situ, the most likely structures from which solar wind plasmas emerge can be identified. In the present paper we review the current understanding of the morphological features present in the solar upper atmosphere and their physical properties such as electron temperature, electron density and elemental abundances. In addition, we discuss these observations in the context of recent theories describing the emergence of new magnetic flux to power the solar wind, and more traditional models that treat the background field and solar wind as a steady phenomenon.
Mapping the deep lithospheric structure beneath the eastern margin of the Tibetan Plateau from gravity anomalies
Authors: Jiang Xiaodian , Jin Yu
Published: July 2005

Various authors have investigated the mechanism of lateral support of the lithosphere in maintaining the uplift of the Tibetan Plateau, based on gravity data and elastic flexural modeling, in the south of the plateau across the Himalayas and in the north and the northwest across the Altyn Tagh and West Kunlun Shan. However, the degree of the regional compensation and lateral support to the east of the Tibetan Plateau has remained unknown. In this paper we present a lithospheric flexure model by interpreting gravity and topography to understand the first‐order problem of lateral support of the lithosphere at the eastern margins of the Tibetan Plateau. The flexural modeling constrains the geometry and strength variation of the lithosphere from the eastern margin of Tibet past the Longmen Shan ranges on to the Sichuan Basin. A lithosphere of intermediate strength (Te = 45 km) beneath the Sichuan Basin is weakened (Te = 36 km) by the thrusting underneath the eastern margin of the Tibetan Plateau. The strength variations indicate that about 10 km of the crustal material of the lithosphere has been ripped off and integrated into the thickened, upper crust of the Tibetan Plateau, which, however, has no appreciable strength. The stiffness of the lithosphere keeps the Tibetan Plateau relatively stable at its eastern margin and enables the weight of the plateau to be supported in the east by the Sichuan. Lithospheric deformation in the southern Longmen Shan area is more pronounced than in the northern region.
Exploitation of Geostationary Earth Radiation Budget data using simulations from a numerical weather prediction model: Methodology and data validation
Authors: Allan Richard P. , Slingo Anthony , Milton Sean F. , Culverwell Ian
Published: July 2005

We describe a new methodology for comparing satellite radiation budget data with a numerical weather prediction (NWP) model. This is applied to data from the Geostationary Earth Radiation Budget (GERB) instrument on Meteosat‐8. The methodology brings together, in near‐real time, GERB broadband shortwave and longwave fluxes with simulations based on analyses produced by the Met Office global NWP model. Results for the period May 2003 to February 2005 illustrate the progressive improvements in the data products as various initial problems were resolved. In most areas the comparisons reveal systematic errors in the model's representation of surface properties and clouds, which are discussed elsewhere. However, for clear‐sky regions over the oceans the model simulations are believed to be sufficiently accurate to allow the quality of the GERB fluxes themselves to be assessed and any changes in time of the performance of the instrument to be identified. Using model and radiosonde profiles of temperature and humidity as input to a single‐column version of the model's radiation code, we conduct sensitivity experiments which provide estimates of the expected model errors over the ocean of about ±5–10 W m−2 in clear‐sky outgoing longwave radiation (OLR) and ±0.01 in clear‐sky albedo. For the more recent data the differences between the observed and modeled OLR and albedo are well within these error estimates. The close agreement between the observed and modeled values, particularly for the most recent period, illustrates the value of the methodology. It also contributes to the validation of the GERB products and increases confidence in the quality of the data, prior to their release.
Halocarbon emissions estimated from Advanced Global Atmospheric Gases Experiment measured pollution events at Trinidad Head, California
Authors: Li Jinlong , Cunnold Derek M. , Wang Hsiang‐Jui , Weiss Ray F. , Miller Ben R. , Harth Chris , Salameh Peter , Harris Joyce M.
Published: July 2005

The emissions of halogenated gases from the West Coast region of the United States are estimated from measurements from 1995 to 2003 at the Advanced Global Atmospheric Gases Experiment site at Trinidad Head, California. The emissions estimation procedure uses pollution events combined with population densities integrated along back trajectories, and the estimates are constrained by independent estimates of CH4 and N2O emissions from the U.S. West Coast region. The best fit, average emissions of CH4 and N2O and the average chloroform emissions in California, Oregon, and Washington combined from 1996 to 2002 are 44, 3.7, and 0.07 kg person−1 yr−1, respectively. The emissions per person of CFC‐11 (CCl3F), CFC‐12 (CCl2F2), CFC‐113 (CCl2FCClF2), and methyl chloroform (CH3CCl3) from California in 1996–1998 are calculated to be factors of approximately 2.2, 1.3, 0.7, and 1.6, respectively, less (more for CFC‐113) than those reported for the northeastern United States by Barnes et al. (2003). The emission per person of all these gases in the U.S. West Coast region decreased from 1998 to 1999 by a factor of 2 or more, but from 1999 to 2002 the estimated emissions of all four gases have remained fairly constant and are 0.016, 0.048, 0.002, and 0.006 kg person−1 yr−1, respectively. The methyl chloroform estimates suggest a delay of up to 1 year in the decline of the emissions from 1996 to 1998, but otherwise, and in 1999–2000, in contrast to the Millet and Goldstein (2004) results, they are in agreement with the average methyl chloroform emissions per person for the United States based on the UNEP country by country consumption figures (A. McCulloch, private communication, 2004). Averaging the Trinidad Head and the Barnes et al. (2003) per person estimates and multiplying by the U.S. population suggests average methyl chloroform emissions in the United States of 18 Gg yr−1 in 1996 to 1998. In 2001–2002, if the ratio of the emissions per person in these two regions was the same as in 1996–1998, we estimate U.S. emissions of 2.2 Gg yr−1, which is one half of the Millet and Goldstein (2004) estimate.
How have soil temperatures been affected by the surface temperature and precipitation in the Eurasian continent?
Authors: Hu Qi , Feng S.
Published: July 2005

In light of the importance of soil temperatures at shallow depths as the source of the deep (terrestrial) soil temperature variations, this study examined how variations of the former have been associated with the surface air temperature (SAT) variations, testing the hypothesis that the deep soil temperatures, e.g., borehole temperatures, can be used as a proxy of the SAT. Over 153 stations in the Eurasian continent were used in the study. Its major results show a dominant SAT effect on the soil temperatures across the continent and over the seasons, but also depict precipitation influences in some regions, most significantly in winter. The latter suggests that the terrestrial soil temperatures may be more accurately considered as a proxy of very low frequency varying climate conditions at the surface.
Global dimming: Clear‐sky atmospheric transmission from astronomical extinction measurements
Authors: Schwartz Richard D.
Published: July 2005

Astronomical seven‐color atmospheric extinction coefficients obtained at the European Southern Observatory, La Silla, Chile, over the period 1978–1997 are analyzed to search for secular trends that might affect the global‐dimming issue. The direct, clear‐sky measurements indicate about a 1% increase in extinction from the years immediately preceding the El Chichon volcanic eruption in 1982 to the quiescent periods 1985–1990 and 1996–1997. A wavelength dependence study of the extinction change suggests that it is consistent with an increase in tropospheric aerosols of meteorological origin. Both the El Chichon and Pinatubo eruptions produced significant perturbations on atmospheric transmission as seen from La Silla. In combination with solar transmission measurements reported from Mauna Loa, the La Silla data and photometric data from other observatories suggest that there has been no large change in the direct, clear‐sky, transmission component of solar or stellar radiation, apart from the effects of volcanic eruptions. It is suggested that the extinction effects of volcanic eruptions may be an important factor in the interpretation of some of the global‐dimming data.
Laser control of vibrational excitation in carboxyhemoglobin: A quantum wave packet study
Authors: Meier Christoph , Heitz Marie-Catherine
Published: July 2005

A coherent control algorithm is applied to obtain complex-shaped infrared laser pulses for the selective vibrational excitation of carbon monoxide at the active site of carbonmonoxyhemoglobin, modeled by the six-coordinated iron-porphyrin-imidazole-CO complex. The influence of the distal histidine is taken into account by an additional imidazole molecule. Density-functional theory is employed to calculate a multidimensional ground-state potential energy surface, and the vibrational dynamics as well as the laser interaction is described by quantum wave-packet calculations. At each instant in time, the optimal electric field is calculated and used for the subsequent quantum dynamics. The results presented show that the control scheme is applicable to complex systems and that it yields laser pulses with complex time-frequency structures, which, nevertheless, have a clear physical interpretation.
Unprejudiced identification of reaction mechanisms from biased transition path sampling
Authors: Zahn Dirk
Published: July 2005

A method for unprejudiced investigation of reaction mechanisms from molecular-dynamics simulations is presented. It combines the transition path sampling approach with a biasing strategy, which (a) allows optimization of transition paths crossing an energy minimum of the transition state surface. The bias is then used to (b) find reaction pathways, which follow different mechanistic routes. In the first step the manifold of similar trajectories that correspond to the same mechanism is reduced to a single characteristic dynamical path. Our method then allows a systematic search for further reaction mechanisms and the related energy barriers. It is illustrated at the example of a single particle in a two-dimensional potential and of the rather complex process of the pressure-induced insertion of a helium atom into a C60 buckyball molecule.
Ab initio molecular-dynamics simulation of aqueous proton solvation and transport revisited
Authors: Izvekov Sergei , Voth Gregory A.
Published: July 2005

The solvation and transport of the hydrated excess proton is studied using the Car-Parrinello molecular-dynamics (CPMD) simulation method. The simulations were performed using BLYP and HCTH gradient-corrected exchange-correlation energy functionals. The fictitious electronic mass was chosen to be small enough so that the underlying water structural and dynamical properties were converged with respect to this important CPMD simulation parameter. An unphysical overstructuring of liquid water in the CPMD simulations using the BLYP functional resulted in the formation of long-lived hydrogen-bonding structures involving the excess proton and a particular (special) water oxygen. The excess proton was observed to be attracted to the special oxygen through the entire length of the BLYP CPMD simulations. Consequently, the excess proton diffusion was limited by the mobility of the special oxygen in the slowly diffusing water network and, in turn, the excess proton self-diffusion coefficient was found to be significantly below the experimental value. On the other hand, the structural properties of liquid water in the HCTH CPMD simulation were seen to be in better agreement with experiment, although the water and excess proton diffusions were still well below the experimental value.
One-photon mass-analyzed threshold ionization spectroscopy of 2-chloropropene (2-C3H5Cl) and its vibrational assignment based on the density-functional theory calculations
Authors: Bae Yong Jin , Lee Mina , Kim Myung Soo
Published: July 2005

A high-quality mass-analyzed threshold ionization (MATI) spectrum of 2-chloropropene, 2-C3H5Cl, is reported. Its ionization energy determined for the first time from the 0-0 band position was 9.5395±0.0006eV. Almost all the peaks in the MATI spectrum could be vibrationally assigned utilizing the frequencies calculated at the B3LYP∕6-311++G(3df,3pd) level and the Franck-Condon factors calculated with the molecular parameters obtained at the same level. In particular, the observed methyl torsional progression could be reproduced very well through quantum-mechanical calculations using the molecular parameters obtained at this level. Dramatic lowering of the torsional barrier inferred from the experimental data was entirely compatible with the B3LYP∕6-311++G(3df,3pd) results. The torsional barrier and the internal rotational constant determined by fits to six torsional peaks were 53.6 and 5.20cm−1, respectively. A brief discussion at the level of molecular orbital is presented to account for the dramatic lowering of the torsional barrier upon ionization.