bluuebunny/crossref_metadata_2025 huggingface dataset:
Solid‐state NMR spectra with sharp principal value features of the chemical shift tensor
Authors: Gardiennet Carole , Tekely Piotr
Published: June 2004

A straightforward, albeit still unexploited, approach to access sharp principal value features of the chemical shift tensor in slightly off‐magic angle, slowly spinning powder solids is revisited. Its major advantages consist of (i) the direct visualization of axial or more general tensor/site symmetry, (ii) the absence of any rotor‐synchronized or amplitude‐matched radiofrequency pulse, and (iii) the use of routine single‐pulse or cross‐polarization acquisition modes upon modest spinning speeds on a standard cross‐polarization/magic‐angle spinning probe. The experiments and simulations show that the principal value features remain well resolved in an easily accessible range of chemical shift anisotropy/spinning frequency ratios and have fixed spectral positions at different spinning speeds. Several useful applications of this simple and robust approach can be envisaged in organic and inorganic solids. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part A 22A: 106–112, 2004
13C CP/MAS: Application to glycine
Authors: Taylor Robert E.
Published: June 2004

In a previous article (Concepts Magn Reson 22A(1) 37–49 (2004)), the initial setup of the 13C CP/MAS experiment was described. The advantages of the experiment over direct 13C excitation were also given. In this article, the experiment is applied to three polymorphic structures of glycine. Temperature calibration of the experiment to investigate molecular dynamics as a function of temperature is also described. Though the 13C CP/MAS experiment is widely applicable, it cannot be universally used. The 13C CP/MAS experiment works at ambient temperature for both the α and γ polymorphic structures of glycine. However, the cross‐polarization technique fails to provide a signal at low temperature from either polymorph. The failure of the technique for both polymorphs arises from the shortened 1H T1ρ at low temperatures. This shortened T1ρ results from the hindered rotation of the −NH3 group. The technique even fails at ambient temperature for β‐glycine. Again, the reason is a shortened 1H T1ρ. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part A 22A: 79–89, 2004
Concepts and tools for NMR restraint analysis and validation
Authors: Nabuurs Sander B. , Spronk Chris A.E.M. , Vriend Gert , Vuister Geerten W.
Published: June 2004

The quality of NMR‐derived biomolecular structure models can be assessed by validation on the level of structural characteristics as well as the NMR data used to derive the structure models. Here, an overview is given of the common methods to validate experimental NMR data. These methods provide measures of quality and goodness of fit of the structure to the data. A detailed discussion is given of newly developed methods to assess the information contained in experimental NMR restraints, which provide powerful tools for validation and error analysis in NMR structure determination. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part A 22A: 90–105, 2004.
A quadrature lowpass birdcage coil for a vertical low field MRI scanner
Authors: Giovannetti Giulio , Francesconi Raffaello , Landini Luigi , Viti Vittorio , Santarelli Maria Filomena , Positano Vincenzo , Benassi Antonio
Published: June 2004

Birdcage coils are widely used in magnetic resonance imaging (MRI) applications for their ability to operate in transmit/receive mode with high signal‐to‐noise ratio and wide homogeneous field. When used in horizontal bore MRI systems, the birdcage coil is able to produce circular polarized field using quadrature excitation, thus reaching SNR improvement of √2 as maximum value. In a previous article, the highpass birdcage coil was employed in a vertical bore MRI scanner by combining the sinusoidal and the end‐ring resonant modes. In this article, we investigated the lowpass birdcage coil configuration to operate with a vertical bore MRI system, producing two B1 fields components perpendicular to the vertical B0 field. Its implementation is convenient because it requires one‐half capacitors with respect to the highpass design. Moreover, at low field, the high near‐electric field losses, which are the main disadvantage of the lowpass design, can be neglected. Experiments performed on a quadrature birdcage coil prototype mounted on an open MRI scanner showed that SNR and homogeneity degree increase with respect to the linear birdcage. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 22B: 1–6, 2004.
Modal analysis and acoustic noise characterization of a 4T MRI gradient coil insert
Authors: Mechefske C.K. , Yao G. , Li W. , Gazdzinski C. , Rutt B.K.
Published: June 2004

High magnetic field strength and high‐speed gradient coil current switching are combining to yield high acoustic sound pressure levels (SPL) in and around magnetic resonance imaging (MRI) scanners. Studies have already been conducted that partially characterize this sound field, and various methods have been investigated in an attempt to attenuate the noise generated. To more fully characterize and predict the vibration and acoustic response of a gradient coil inside a scanner, a series of finite element analysis (FEA), vibro‐acoustic analysis, and experimental measurements were carried out. The FEA and vibro‐acoustic model used was based on specific internal and external structural dimensions and the material physical properties of a gradient coil insert. The model‐based results were verified through experimental vibration and acoustic testing of the same gradient coil. It was found that the experimental analysis results were in good agreement with the model‐based results in all cases. The numerical methods developed in this study could provide a basis for the virtual testing of gradient coil designs that will allow the prediction of vibration and acoustic behavior. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 22B: 37–49, 2004
Simultaneous NMR microimaging of multiple single‐cell samples
Authors: Purea A. , Neuberger T. , Webb A.G.
Published: June 2004

Nuclear magnetic resonance (NMR) microimaging experiments performed on small samples such as single cells typically require long data acquisition times and are usually carried out on high‐field systems with limited access time. When using small probe coils on millimetre (or smaller) size scale to study single cells, it is desirable to take advantage of the comparatively large volume of homogeneous static magnetic field within the magnet to increase the efficiency of NMR data acquisition. Here we describe the development of a four‐channel probehead that consists of four individual solenoid coils (length 2.8 mm, outer diameter 2 mm) stacked along the z axis. The probehead was designed for a 17.6 Tesla (750 MHz) wide‐bore magnet, and operates within a 40 mm inner diameter gradient set with maximum strength 1 Tesla per metre. We performed simulations to estimate the impact of shielding between the coils on the B1 field distribution. Results showed that for coil‐shield separations on the order of a coil radius, no significant change in B1 homogeneity is expected, and therefore coils were spaced accordingly. Coil isolation of greater than 35 dB was achieved for all coils, and the Q values were ∼160 unloaded and ∼60 loaded with 100 mM NaCl solution. Practical use of the probehead was demonstrated by obtaining simultaneously four three‐dimensional T1 maps of chemically fixed Xenopus laevis oocytes at a spatial resolution of 30 × 60 × 60 μm. The T1 values for the nucleus were ∼2.7 seconds, and the animal pole ∼1.2 seconds. © 2004 Wiley Periodicals, Inc. Concepts Magn Reson Part B (Magn Reson Engineering) 22B: 7–14, 2004.
Intestinal tumor and agmatine (decarboxylated arginine)
Authors: Molderings Gerhard J. , Kribben Bettina , Heinen Anja , Schröder Detlev , Brüss Michael , Göthert Manfred
Published: June 2004

BACKGROUND

The polyamine system is a promising target for anticancer therapy. Ideally, an antineoplastic compound affecting this system should inhibit both ornithine decarboxylase and the polyamine transporter, and toxicity should be mild. Agmatine, decarboxylated L‐arginine, appears to be such a compound.

METHODS

Adenosine triphosphate levels and the protein content of cell populations in culture were identified as surrogate markers for cell count. Agmatine content in cells and tissue specimens was measured by high‐performance liquid chromatography. Antizyme levels were estimated by Western blotting.

RESULTS

Agmatine inhibited the proliferation of six human intestinal tumor cell lines in a concentration‐dependent manner; this inhibition probably was attributable to an interaction between agmatine and the intracellular polyamine system. Consistent with the inverse relation between cell proliferation and agmatine concentration was the finding that agmatine content in human colon carcinoma tissue was approximatly one‐half as great as it was in adjacent macroscopically normal tissue.

CONCLUSIONS

The results of the current study were compatible with the hypothesis that agmatine possesses antineoplastic action against intestinal tumor cells. It is likely that this activity is attributable to agmatine's regulatory role in polyamine homeostasis. Cancer 2004. © 2004 American Cancer Society.
Depression, cigarette smoking, and hematopoietic stem cell transplantation outcome
Authors: Chang Grace , John Orav E. , McNamara Tay , Tong Mei‐Yee , Antin Joseph H.
Published: June 2004

BACKGROUND

The relationships between psychological and behavioral variables and patient outcomes after hematopoietic stem cell transplantation (HSCT) are not known definitively but have great potential importance, since this lifesaving procedure is used increasingly to treat a variety of malignancies. The objective of this study was to evaluate psychosocial predictors of long‐term survival and disease recurrence after patients underwent allogeneic HSCT for chronic myelogenous leukemia (CML).

METHODS

In this prospective cohort study, 114 adults were admitted for allogeneic HSCT to the Brigham and Women's Hospital between July, 1997 and January, 2002. The median follow‐up was 882 days, and serial measures were taken for mood and substance use 6 months and 12 months posttransplantation.

RESULTS

With a 93% participation rate by all potentially eligible patients and with < 3% of patients loss to follow‐up, univariate predictors of long‐term survival and recurrence were identified. Cox proportional hazards regression models for survival and recurrence were developed. Depressive symptoms, as measured by the most recent Beck Depression Inventory (BDI), increased the risk of death by 7% for each point increase in the BDI score (P = 0.006). Fourteen of 17 patients who developed recurrent disease were cigarette smokers with an average of 22.3 pack‐years. For each pack‐year of cigarette smoking, the risk of recurrence increased by 1.7% (P = 0.01).

CONCLUSIONS

This study assessed the role of psychosocial variables prospectively among a clinically homogeneous but representative cohort of patients who underwent allogeneic HSCT. Although additional confirmatory studies are pending, it appears that depressive symptoms posttransplantation and cigarette smoking prior to transplantation affect outcomes adversely and may represent opportunities to improve the morbidity and mortality associated with HSCT for patients with CML. Cancer 2004. © 2004 American Cancer Society.
Estimation of an optimal radiotherapy utilization rate for gastrointestinal carcinoma
Authors: Delaney Geoff , Barton Michael , Jacob Susannah
Published: June 2004

BACKGROUND

Radiotherapy utilization rates for cancer vary widely, both within and between countries. The optimal proportion of patients with gastrointestinal malignancies who should receive at least one course of radiotherapy at some time during their illness is an important benchmark.

METHODS

The authors studied treatment guidelines and treatment reviews to identify the indications for radiotherapy for patients with gastrointestinal malignancies. Optimal radiotherapy utilization trees were constructed to show the clinical attributes of patients with gastrointestinal carcinomas who will benefit from radiotherapy. Epidemiologic incidence data for each of these clinical attributes were obtained to calculate the optimal proportion of all patients with gastrointestinal malignancies for whom radiotherapy was considered appropriate. Optimal rates of radiotherapy use were compared with actual rates in population‐based studies to assess any discrepancies between actual and optimal radiotherapy utilization rates.

RESULTS

Radiotherapy was indicated in 80% of patients with esophageal carcinoma, 68% of patients with gastric carcinoma, 57% of patients with pancreatic carcinoma, 13% of patients with carcinoma of the gallbladder, 0% of patients with hepatic carcinoma, 14% of patients with colon carcinoma, and 61% of patients with rectal carcinoma. The actual radiotherapy utilization rates for most of these gastrointestinal malignancies fell well short of optimal rates, which were derived from evidence‐based treatment guidelines.

CONCLUSIONS

It is possible to model optimal radiotherapy utilization using published treatment guidelines and existing incidence data. There was a discrepancy between the optimal and actual rates of radiotherapy utilization for patients with carcinomas of the esophagus, stomach, pancreas, and rectum. Strategies to implement evidence‐based clinical guidelines are recommended. Cancer 2004. © 2004 American Cancer Society.
Estimation of an optimal radiotherapy utilization rate for gynecologic carcinoma
Authors: Delaney Geoff , Jacob Susannah , Barton Michael
Published: June 2004

BACKGROUND

Radiotherapy utilization rates for cancer vary widely, both within and between countries. Current estimates of the proportion of cancer patients who should optimally receive radiotherapy are based either on expert opinion or on the measurement of actual utilization rates, rather than on the best scientific evidence.

METHODS

Evidence‐based treatment guidelines regarding endometrial carcinoma were reviewed to develop an evidence‐based benchmark for radiotherapy utilization. An optimal radiotherapy utilization tree was constructed and the proportions of endometrial carcinoma patients with clinical indications for radiotherapy were obtained from epidemiologic data. The ideal utilization rates were compared with actual radiotherapy utilization rates for endometrial carcinoma both in Australia and internationally.

RESULTS

According to the best available evidence, radiotherapy is indicated at least once in 46% of all patients with endometrial carcinoma. A review of the limited data available concerning actual radiotherapy utilization rates revealed that the actual rates are approximately 10% lower than the optimal rates.

CONCLUSIONS

Further research into the patterns of actual treatment and the development of optimal chemotherapy and surgery utilization rates for endometrial carcinoma is recommended. The difference between the optimal and the actual utilization rates warrants investigation into the reasons for the low radiotherapy utilization rates encountered in clinical practice. Cancer 2004. © 2004 American Cancer Society.
Negotiating emotions
Authors: Shapiro Daniel L.
Published: June 2004

Folk wisdom suggests that a negotiator (1) should avoid getting emotional and (2) is a passive recipient of the whims of emotion. In this article, I argue that both of these notions are false and that a better pair of assumptions is that (1) emotions can positively affect our ability to reach negotiation goals and (2) we can actively negotiate which emotions are experienced and how intensely. I extend the emotional appraisal work of Lazarus (1991) and Parkinson (1995) by suggesting that we appraise situations emotionally for their personal relevance by evaluating relational identity concerns—namely autonomy and affiliation. Negotiating emotions entails negotiating these relational identity concerns and the tensions that a conflicting set of concerns can create.
Aspects of grief in conflict: Re‐visioning response to dispute
Authors: Evans Michael J. , Tyler‐Evans Marcia
Published: June 2004

Although there are multiple theories on the causes of conflict and methods of managing dispute, one factor is not explicitly discussed; grief. Just as grief attends the physical loss of a loved one, it also attends the loss associated with conflict. Whether the loss is the position as winner, partner, provider, or good neighbor, being deprived of that identity is emotionally threatening. Grief affects the persons ability to function within the resolution process. By learning to acknowledge and allow expressions of grief within the conflict process, we increase our ability to promote resolution.
Gender differences in content and style of argument between couples during divorce mediation
Authors: Pines Ayala Malach , Gat Hamutal , Tal Yael
Published: June 2004

Analysis of the negotiation process of thirty Israeli couples, chosen randomly, who participated in divorce mediation shows several gender differences in both style and content. Men tend to use more legalistic arguments that are based on principles of law and customary practice. Women tend to use more relational arguments based on interpersonal responsibility to a relationship. Men's style tends to be unemotional and reserved, women's style emotional with more expression of insult and pain. Psychological theories help explain these gender differences. Couple therapists, divorce counselors, and mediators should be aware of these differences and their practice implications.
From financial to sustainable profit
Authors: Cramer Jacqueline
Published: June 2004

This article explains why sustainable business has caught the spotlight at this particular time. Main drivers are the shift in power relationships between states, firms and households, the emergence of civil regulation and the communication through networks. The implication of this trend towards sustainable business is that firms will consciously need to focus on creating value not only in financial terms, but also in ecological and social terms. The challenge facing the business sector is how to set about meeting these expectations. Firms will need to change not only in themselves, but also in the way they interact with their environment. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment
Applying organizational environmental tools and techniques
Authors: Lawrence Elaine , Andrews Duncan , Ralph Brian , France Chris
Published: June 2004

Although the application of tools and techniques to support environmental decision‐making is increasing within organizations, there is concern that they are not bringing the desired improvements in performance. A key reason is that tools/techniques need to be placed in context so that they also support the overall aims of the business. Within the ISO14000 series there are two techniques defined, auditing and life cycle assessment (LCA), but there are a growing number of tools and techniques that are outside the scope of the standards. For those in organizations tasked with implementing environmental improvements identifying appropriate tools and techniques can be a daunting task. A process identifying and aligning environmental tools and techniques within a business wide context is presented, supported by the results of a practical application over a two‐year period within a UK automotive supplier. The results from application suggest that this approach should be useful for other organizations. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment
The relationship between the environmental and economic performance of firms: an empirical analysis of the European paper industry
Authors: Wagner Marcus , Van Phu Nguyen , Azomahou Théophile , Wehrmeyer Walter
Published: June 2004

This paper examines the relationship between the environmental and economic performance of firms in the European paper manufacturing industry. It initially discusses possible functional relationships between environmental and economic performance rooted in different theoretical frameworks and links these to recent empirical and theoretical analyses of the Porter hypothesis. Following this, it reports the results of an empirical study carried out in the European paper industry. Findings fit better with ‘traditionalist’ reasoning about the relationship between environmental and economic performance, which predicts the relationship to be uniformly negative. In particular they confirm the necessity for a more differentiated view of the Porter hypothesis. Copyright © 2002 John Wiley & Sons, Ltd. and ERP Environment.
Dual‐Source Atmospheric Pressure CVD of Amorphous Molybdenum Phosphide Films on Glass Using Molybdenum(V) Chloride and Cyclohexylphosphine
Authors: Blackman C.S. , Carmalt C.J. , Manning T.D. , O’Neill S.A. , Parkin I.P. , Apostolico L. , Molloy K.C.
Published: June 2004

Molybdenum phosphide films are deposited on glass from MoCl5 and 2P(C6H11)H2. The atmospheric pressure depositions are carried out at 550 and 600 °C producing silver brown shiny films. The composition of the film is shown to be MoP1.8 with a resistivity value of ca. 3800 μΩ cm. X‐ray analysis of the deposited films indicates that they are amorphous. XPS analysis revealed binding energy shifts of 228.4 eV for Mo 3d5/2 and 128.8 eV for P 2p. The deposits passed the scotch test and could not be scratched with steel or brass scalpels. They are also resistant to common solvents but dissolve in concentrated acids.
Atomic Layer Deposition of Epitaxial and Polycrystalline SnO2 Films from the SnI4/O2 Precursor Combination
Authors: Sundqvist J. , Tarre A. , Rosental A. , Hårsta A.
Published: June 2004

Thin films of SnO2 have been successfully deposited by atomic layer deposition (ALD) using the SnI4/O2 precursor combination. Depositions were carried out in the temperature range 400–750 °C on SiO2/Si(100) and single‐crystalline α‐Al2O3(012) substrates. The films were found to grow as the tetragonal SnO2 phase (cassiterite), polycrystalline on SiO2/Si(100), and epitaxial on the α‐Al2O3(012) substrates with the in‐plane orientation relationships [010] ∥ [100] and [10$\bar 1$] ∥ [$\bar 1$$\bar 2$1]. In general the growth rate was high, changing from 0.10 nm cycle–1 at 500 °C to 0.12 nm cycle–1 at 750 °C for the α‐Al2O3(012) substrates, and from 0.04 nm cycle–1 at 400 °C to 0.24 nm cycle–1 at 750 °C for the SiO2/Si(100) substrates.
Template‐Directed CVD of Dielectric Nanotubes
Authors: Zambov L. , Zambova A. , Cabassi M. , Mayer T.S.
Published: June 2004

Fabrication of dielectric nanotubes from silicon dioxide and silicon nitride by a template‐based electron cyclotron resonance (ECR) plasma‐enhanced (PE) CVD is described. The nanotubes synthesized from SiH4‐O2 and SiH4‐N2 binary source reagent systems are smooth, transparent and at least 10 μm long. A mathematical description of the template‐directed nanometer‐scale CVD is developed to elucidate the appropriate process parameters that enable growth of high‐aspect‐ratio nanotubes with uniform wall thickness. The analysis of the model, by establishing general trends between process operating conditions and geometrical characteristics of the nanotubes, clarifies the mechanism of nanoscale CVD. The dielectric nanotubes obtained provide many opportunities for fabricating composite nanostructures and nanodevices.
In‐Situ Optical Pyrometry in the CVD of Metallic Thin Films for Real Time Control of the Growth
Authors: Gasqueres C. , Maury F. , Ossola F.
Published: June 2004

In‐situ temperature measurement is essential in CVD in order to control the temperature of the growing films. This is frequently achieved by optical pyrometry because it is a sensitive, convenient, and inexpensive technique that can be used in corrosive atmospheres. In this work, in‐situ IR pyrometry has been used, not for direct measurement of the temperature, but for real time monitoring of the early stages of the growth of metallic‐type thin films, selected as a model system. Significant variations in the pyrometric signal were observed during the metal–organic (MO) CVD of CrCxNy thin films due to changes of emissivity of the film/substrate system. The pyrometric signal (or emissivity) depends predominantly on the nature, thickness, and surface roughness of the growing film. As a result, fruitful information as to the formation of an interphase, or the existence of an induction period, can be obtained in real time by this detection technique. Radiation pyrometry can be used as a surface diagnostic tool for the growth of a large variety of thin film materials that exhibit an emissivity sufficiently different from that of the substrate.
In‐Situ Preparation of Polymer‐Coated Alumina Nanopowders by Chemical Vapor Synthesis
Authors: Schallehn M. , Winterer M. , Weirich T.E. , Keiderling U. , Hahn H.
Published: June 2004

Nanocrystalline alumina particles coated with polyethylene have been prepared by a two‐step chemical vapor synthesis (CVS) process using a hot‐wall reactor to synthesize the nanocrystalline alumina core, and a RF plasma reactor for the subsequent polymer coating. The particle radius is about 4 nm, with the radius of the ceramic core being about 2.5 nm and the coating thickness about 1.5 nm. The powders have been characterized by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), Brunauer–Emmett–Teller (BET), small‐angle neutron scattering (SANS), and high‐resolution transmission electron microscopy (HRTEM).
Growth of Lanthanum Silicate Thin Films by Liquid Injection MOCVD Using Tris[bis(trimethylsilyl)amido]lanthanum
Authors: Aspinall H.C. , Williams P.A. , Gaskell J. , Jones A.C. , Roberts J.L. , Smith L.M. , Chalker P.R. , Critchlow G.W.
Published: June 2004

Lanthanum silicate is deposited from a single‐source precursor by injection MOCVD using La[N(SiMe3)2]3 as precursor. The depositions are carried out over 350–600 °C without an additional silicon source. SEM analysis (Figure) shows that deposited films are smooth and featureless. AES analysis indicates that all the films are lanthanum silicate with silicon concentration ranging from 8.5 to 15.2 at.‐%.
Secretory phospholipase A2 induces dendritic cell maturation
Authors: Perrin‐Cocon Laure , Agaugué Sophie , Coutant Frédéric , Masurel Aurélie , Bezzine Sofiane , Lambeau Gérard , André Patrice , Lotteau Vincent
Published: June 2004

High level of phospholipase A2 (PLA2) activity is found in serum and biological fluids during the acute‐phase response (APR). Extracellular PLA2 in fluids of patients with inflammatory diseases such as sepsis, acute pancreatitis or rheumatoid arthritis is also associated with propagation of inflammation. PLA2 activity is involved in the release of bothpro‐ and anti‐inflammatory lipid mediators from phospholipids of cellular membranes or circulating lipoproteins. PLA2 may thus generate signals that influence immune responses. Here, groupIII secretory PLA2 were tested for their ability to promote generation of functionally mature human dendritic cells (DC). PLA2 treatment of differentiating monocytes in the presence of granulocyte/macrophage colony‐stimulating factor and IL‐4 yielded cells with phenotypical and functional characteristics of mature DC. This maturation was dependent on the dose of PLA2, and PLA2‐generated DC stimulated IFN‐γ secretion by allogeneic T cells. The effects of PLA2 on DC maturation was mainly dependent on enzyme activity and correlated with the activation of NF‐κB, AP‐1 and NFAT. The data suggest that transient increase in PLA2 activity generates signals that promote transition of innate to adaptive immunity during the APR.
Biological function of the soluble CEACAM1 protein and implications in TAP2‐deficient patients
Authors: Markel Gal , Achdout Hagit , Katz Gil , Ling Khoon‐Lin , Salio Mariolina , Gruda Raizy , Gazit Roi , Mizrahi Sa'ar , Hanna Jacob , Gonen‐Gross Tsufit , Arnon Tal I , Lieberman Niva , Stren Noam , Nachmias Boaz , Blumberg Richard S. , Steuer Guy , Blau Hanna , Cerundolo Vincenzo , Mussaffi Huda , Mandelboim Ofer
Published: June 2004

Interactions of natural killer (NK) cells with MHC class I proteins provide the main inhibitory signals controlling NK killing activity. It is therefore surprising to learn that TAP2‐deficientpatients suffer from autoimmune manifestations only occasionally in later stages of life. We have previously described that the CEACAM1‐mediated inhibitory mechanism of NK cytotoxicity plays a major role in controlling NK autoreactivity in three newly identified TAP2‐deficient siblings. This novel mechanism probably compensates for the lack of MHC class I‐mediated inhibition. The CEACAM1 protein can also be present in a soluble form and the biological function of the soluble form of CEACAM1 with regard to NK cells has not been investigated. Here we show that the homophilic CEACAM1 interactions are abrogated in the presence of soluble CEACAM1 protein in a dose‐dependent manner. Importantly, the amounts of soluble CEACAM1 protein detected in sera derived from the TAP2‐deficient patients were dramatically reduced as compared to healthy controls. This dramatic reduction does not depend on the membrane‐bound metalloproteinase activity. Thus, the expression of CEACAM1 and the absence of soluble CEACAM1 observed in the TAP2‐deficient patients practically maximize the inhibitory effect and probably help to minimize autoimmunity in these patients.
Heavy Metals in Matrices of Food Interest: Sequential Voltammetric Determination at Trace and Ultratrace Level of Copper, Lead, Cadmium, Zinc, Arsenic, Selenium, Manganese and Iron in Meals
Authors: Locatelli Clinio
Published: June 2004

The voltammetric methods are very suitable and versatile techniques for the simultaneous metal determination in complex matrices. The present work, regarding the sequential determination of Cu(II), Pb(II), Cd(II), Zn(II) by square‐wave anodic stripping voltammetry (SWASV), As(III), Se(IV) by square‐wave cathodic stripping voltammetry (SWCSV) and Mn(II), Fe(III) by square‐wave voltammetry (SWV) in matrices involved in foods and food chain as wholemeal, wheat and maize meal, are an interesting example of the possibility to sequentially determine each single element in real samples. Besides the set up of the analytical method, particular attention is aimed either at the problem of possible signal interference or to show that, using the peak area Ap as instrumental datum, it is possible to achieve lower limits of detection. The analytical procedure was verified by the analysis of the standard reference materials: Wholemeal BCR‐CRM 189, Wheat Flour NIST‐SRM 1567a and Rice Flour NIST‐SRM 1568a. Precision, as repeatability, and accuracy, expressed as relative standard deviation and relative error, respectively, were lower than 6% in all cases. In the presence of reciprocal interference, the standard addition method considerably improved the resolution of the voltammetric technique. Once set up on the standard reference materials, the analytical procedure was transferred and applied to commercial meals sampled on market for sale. A critical comparison with spectroscopic measurements is also discussed.
Nickel Amperometric Detector Prepared by Electroless Deposition for Microchip Electrophoretic Measurement of Alcohols and Sugars
Authors: Wang Joseph , Chen Gang , Chatrathi Madhu Prakash
Published: June 2004

Nickel was deposited directly at the end of an electrophoretic glass microchip using an electroless deposition procedure leading to an attractive amperometric detector for sugars and alcohols. Such direct electroless deposition of nickel at the end of the separation chip greatly simplifies the preparation of on‐chip electrochemical detectors. Variables affecting the preparation and operation of the new detector are characterized and optimized. The integrated capillary electrophoresis‐electrochemical detection microsystem was evaluated for the separation of alcohols and sugars in connection to assays of different beer and wine samples. Linear calibration plots and favorable detection limits are found that meet the needs of real sample (wine and beer) analyses. This represents the first example of using nickel electrode and detecting alcohols on microchip platforms.
A Monitoring System for Selective Determination of Alkylphenol Ethoxylates by the Adsorptive Stripping‐Indirect Tensammetric Technique
Authors: Stasiewicz C. , Szymanski A. , Lukaszewski Z.
Published: June 2004

A new monitoring system for the adsorptive stripping‐indirect tensammetric technique has been developed. The system responded selectively to alkylphenol ethoxylates having 5–14 oxyethylene subunits (APE) (being a fraction of nonionic surfactants). It consists of 20 ppm of Mannoxol OT and 20 ppb of tetrabutylammonium bromide (TBAB). In the presence of APE a tensammetric peak of the monitoring mixture is growing. A calibration plot has a slightly sigmoidal shape; the dynamic response range is from 0.5 to 2.0 μg and the detection limit is 0.075 μg. APE determination is highly tolerant to alcohol ethoxylates (AE) having a C18 hydrophobic part, however, the tolerance of AE having a C12 hydrophobic part is small (the APE signal is only three times higher than that of AE having a C12 hydrophobic part). An analytical response to a mixture consisting different nonionic surfactants (NS) is approximately additive. The developed monitoring system was applied to the determination of an APE fraction in 14 river water samples. NS were separated from the water matrix by liquid‐liquid extraction with chloroform. The recovery of Triton X‐100 spike was 102% and the precision 6.5%.
Sensitive Electrochemical Detection of Native and Aggregated α‐Synuclein Protein Involved in Parkinson's Disease
Authors: Masařík Michal , Stobiecka Agata , Kizek René , Jelen František , Pechan Zdeněk , Hoyer Wolfgang , Jovin Thomas M. , Subramaniam Vinod , Paleček Emil
Published: June 2004

The aggregation of α‐synuclein, a 14 kDa protein, is involved in several human neurodegenerative disorders, including Parkinson's disease. We studied native and in vitro aggregated α‐synuclein by circular dichroism (CD), atomic force microscopy (AFM) and electrochemical methods. We used constant current chronopotentiometric stripping analysis (CPSA) to measure hydrogen evolution catalyzed by α‐synuclein (peak H) at hanging mercury drop electrodes (HMDE) and square‐wave stripping voltammetry (SWSV) to monitor tyrosine oxidation at carbon paste electrodes (CPE). To decrease the volume of the analyte, most of the electrochemical measurements were performed by adsorptive transfer (medium exchange) from 3–6 μL drops of α‐synuclein samples. With both CPE and HMDE we observed changes in electrochemical responses of α‐synuclein corresponding to protein fibrillization detectable by CD, fluorescence and AFM. Aggregation‐induced changes in peak H at HMDE were relatively large in strongly aggregated samples, suggesting that this electrochemical signal may find use in the analysis of early stages of α‐synuclein aggregation. This assumption was documented by marked changes in the peak H potential and height in samples withdrawn at the end of the lag and the beginning of the elongation phase. Native α‐synuclein can be detected down to subnanomolar concentrations by CPSA.
Capillary electrophoresis coupled to mass spectrometer for automated and robust polypeptide determination in body fluids for clinical use
Authors: Kaiser Thorsten , Wittke Stefan , Just Ingo , Krebs Ronald , Bartel Sebastian , Fliser Danilo , Mischak Harald , Weissinger Eva M.
Published: June 2004

We describe the application of capillary electrophoresis (CE) coupled on‐line to an electrospray ionization‐time of flight‐mass spectrometer (ESI‐TOF‐MS) to the analysis of human urine and serum for the identification of biomarkers for clinical diagnostics. CE‐MS led to display > 1000 polypeptides present in complex biological samples within 45–60 min in a single analysis run. To extract the information of the CE‐MS spectra in a timely fashion, a software was designed to automatically deconvolute and normalize the spectra. Both urine and serum contain several hundred polypeptides in samples from healthy individuals. Hence, it is possible to establish typical “normal urine” or “normal serum” polypeptide patterns. Samples from patients with different diseases display polypeptide patterns that differ significantly from those obtained from healthy individuals. Examining series of patients with the same disease allowed the establishment of polypeptide patterns typical for specific diseases. This permits the search for marker peptides specific for diseases. The data indicate that a single polypeptide present in all patients with the same disease, but absent in all healthy control individuals does not exist. The combination of several polypeptides found in either urine or serum or both are forming a specific pattern, which is indicative not only for the particular disease, but also for the stage of disease. CE‐MS detects many polypeptides in single samples and the application of the software to the search of identical polypeptides excreted in urine allows the unbiased diagnosis based on a pattern and does not rely on single disease markers.
Capillary electrophoresis‐mass spectrometry of basic proteins using a new physically adsorbed polymer coating. Some applications in food analysis
Authors: Simó Carolina , Elvira Carlos , González Nieves , San Román J. , Barbas Coral , Cifuentes Alejandro
Published: June 2004

A new physically adsorbed capillary coating for capillary electrophoresis‐mass spectrometry (CE‐MS) of basic proteins is presented, which is easily obtained by flushing the capillary with a polymer aqueous solution for two min. This coating significantly reduces the electrostatic adsorption of a group of basic proteins (i.e., cytochrome c, lysozyme, and ribonuclease A) onto the capillary wall allowing their analysis by CE‐MS. The coating protocol is compatible with electrospray inonization (ESI)‐MS via the reproducible separation of the standard basic proteins (%RSD values (n = 5) < 1% for analysis time reproducibility and < 5% for peak heights, measured from the total ion electropherograms (TIEs) within the same day). The LODs determined using cytochrome c with total ion current and extracted ion current defection were 24.5 and 2.9 fmol, respectively. Using this new coating lysozymes from chicken and turkey egg white could be easily distinguished by CE‐MS, demonstrating the usefulness of this method to differentiate animal species. Even after sterilization at 120°C for 30 min, lysozyme could be detected, as well as in wines at concentrations much lower than the limit marked by the EC Commission Regulation. Adulteration of minced meat with 5% of egg‐white could also be analysed by our CE‐MS protocol.
Qualitative and quantitative analysis of amino acids by capillary electrophoresis‐electrospray ionization‐tandem mass spectrometry
Authors: Soga Tomoyoshi , Kakazu Yuji , Robert Martin , Tomita Masaru , Nishioka Takaaki
Published: June 2004

We describe a method to identify and quantify amino acids using capillary electrophoresis‐electrospray ionization‐triple‐quadrupole tandem mass spectrometry (CE‐ESI‐MS/MS). Amino acids, including physiological amino acids, were first separated by CE under acidic pH conditions and then detected by MS/MS. To efficiently introduce the whole sample into the capillary, no electrical potential was applied to the electrospray probe until running electrophoresis. The position of the electrosprayer with respect to the MS capillary entrance drastically affected sensitivity and generation of cluster ions. MS/MS with multiple reaction monitoring (MRM) detection was performed to obtain sufficient selectivity and sensitivity. Under optimized CE‐MS/MS conditions, the minimum detectable levels for 32 free amino acids normally found in proteins and other physiological amino acids were between 0.1 and 14 μmol/L with pressure injection of 50 mbar for 3 s (3 nL) at a signal‐to‐noise ratio of 3. For most amino acids, this constitutes a severalfold increase in sensitivity compared to CE‐MS. The relative standard deviations (% RSD) for all amino acids were better than 0.4% for migration times and between 1.4% and 8.6% for peak areas (n = 10). Since amino acids exhibited characteristic MS/MS spectra, this approach is useful for the simultaneous, selective, quantitative, and reproducible analysis of amino acids in physiological and biological samples that contain various kinds of matrices. The power of the method was demonstrated by analyzing amino acids in human urine.
Analysis of high‐mannose‐type oligosaccharides by microliquid chromatography‐mass spectrometry and capillary electrophoresis
Authors: Koller Antonius , Khandurina Julia , Li Jincai , Kreps Joel , Schieltz David , Guttman András
Published: June 2004

We report on microbore liquid chromatography (μLC) and capillary electrophoresis (CE) separation of glycopeptides and high‐mannose‐type oligosaccharides, digested from recombinant phospholipase C, expressed in Pichia pastoris. The glycopeptides were subject to μLC/electrospray ionization/mass spectrometry (ESI‐MS) and μLC/ESI‐tandem MS (MS/MS) analysis that revealed high‐mannose structure size variation between Man7GlcNAc2 and Man14GlcNAc2. Then, high‐performance CE was applied to identify possible positional isomers of the high‐mannose structures. For the CE experiments, the oligosaccharides were released from the glycoproteins by peptide‐N‐glycosidase F and labeled with 1‐aminopyrene‐3,6,8‐trisulfonic acid (APTS). Excellent separation of the possible positional isomers was attained, suggesting one for Man9GlcNAc2, two for Man10GlcNAc2, three for Man11GlcNAc2, Man12GlcNAc2, and Man13GlcNAc2, and two for Man14GlcNAc2. The CE results provided complementary information to the μLC/ESI‐MS and MS/MS data with respect to the possible number of positional isomers.
Application of capillary electrophoresis‐mass spectrometry to synthetic in vitro glycolysis studies
Authors: Itoh Aya , Ohashi Yoshiaki , Soga Tomoyoshi , Mori Hirotada , Nishioka Takaaki , Tomita Masaru
Published: June 2004

We propose an approach designed to reconstitute a metabolic pathway composed of multistep biochemical reactions, rather than to dissect the individual reactions that make up the pathway. A synthetic in vitro glycolysis was reconstructed from ten purified Escherichia coli (E. coli) enzymes to obtain a better understanding of the regulation of sequential enzymatic reactions. The key to the success of this approach is the ability to perform direct and simultaneous determination of the diverse metabolic intermediates in the pathway by capillary electrophoresis‐mass spectrometry. We observed that the pathway is regulated by a delicate balance between the changing metabolite concentrations and behaves like a natural biological oscillating network that has hitherto not been reported for E. coli glycolysis. The end‐product, pyruvate, was periodically synthesized from glucose at an overall efficiency of 30%, corresponding to an average of 90% conversion efficiency for each of the ten steps involved. This approach is likely useful for the synthesis of natural products requiring complex sequential biocatalytic reactions.
Application of capillary electrophoresis/ electrospray ionization‐mass spectrometry to subcellular proteomics of Escherichia coli ribosomal proteins
Authors: Moini Mehdi , Huang Hsiaoling
Published: June 2004

We introduce capillary electrophoresis‐mass spectrometry (CE‐MS) as an efficient means for the on‐line separation and identification of protein mixtures. It was found that while CE/electrospray ionization (ESI)‐MS analysis of whole‐cell lysate was too complicated for the one‐dimensional CE‐MS analysis, the technique was useful for the analysis of protein mixtures of moderate complexity (∼50 intact proteins). CE/ESI‐MS was applied to the subcellular proteomics of ribosomal Escherichia coli. 55 out of the 56 ribosomal proteins were detected with ease by using only ∼3.4 ng of ribosomal proteins. In addition, it was found that the mass accuracy of the conventional MS (such as quadrupole ion traps) was good enough to identify many post‐translational modifications of the intact proteins by simply comparing their measured average molecular weight with the average molecular weight predicted from gene banks.
State‐of‐the‐art of the hyphenation of capillary electrochromatography with mass spectrometry
Authors: Barceló‐Barrachina Elena , Moyano Encarnación , Galceran M. Teresa
Published: June 2004

The high separation efficiency and loading capacity of capillary electrochromatography (CEC) make it an attractive separation mode for coupling with mass spectrometry (MS), which has the ability to unambiguously identify analytes with high selectivity and sensitivity. We present an overview of recent advances on both instrumentation and separation columns employed in CEC‐MS systems. In particular, the main characteristics of the stationary phases, as well as the configurations of the column outlet that are related with the coupling arrangements of the MS ionization sources, are reported. At present, packed columns and conventional electrospray ionization (ESI) sources are mainly employed in CEC‐MS. Nevertheless, the use of monolithic capillary columns and nanoelectrospray sources has the potential for wide acceptance in the next future. Moreover, the main features of several mass analyzers including ion trap, quadrupole, time‐of‐flight, magnetic sector, and Fourier transform‐ion cyclotron resonance are examined. Finally, current applications of this technology, mainly in the pharmaceutical field and proteomics, are reviewed.
Characterization of glyco isoforms in plasmaderived human antithrombin by on‐line capillary zone electrophoresis‐electrospray ionization‐quadrupole ion trap‐mass spectrometry of the intact glycoproteins
Authors: Demelbauer Uwe M. , Plematl Alexander , Kremser Leopold , Allmaier Günter , Josic Djuro , Rizzi Andreas
Published: June 2004

The carbohydrate structures of five isoforms of α‐AT and two isoforms of β‐AT were determined by applying capillary zone electrophoresis (CZE) on‐line coupled to electrospray ionization‐mass spectrometry (ESI‐MS) using an ion‐trap analyzer. For the AT preparations gained from a plasma pool at least semiquantitative information on the isoform‐distributions could be gained. Unlike to the commonly used approaches starting from enzymatically treated glycoproteins, this approach deals with intact proteins. The high accuracy of the molecular mass determination obtained by the ion‐trap analyzer allows one to calculate and ascertain the carbohydrate composition assuming no variations in the protein moiety of AT and to exclude or confirm the presence of the potential post‐translational or other modifications. Therefore, the direct coupling of CZE with ESI‐MS does not only represent a fast alternative technique to two‐dimensional electrophoresis (2‐DE) but serves as a method which provides structural information complementary to that gained from peptide mapping methods.