bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of a Candidate Primary Reference Material for the International Standardisation of HbA1c Determinations
Authors: Finke Andreas , Kobold Uwe , Hoelzel Wieland , Weykamp Cas , Miedema Kor , Jeppsson Jan-Olof
Published: October 2004

We prepared a candidate primary reference material for the forthcoming international standardisation of β-N-terminal glycated hemoglobin A measurements. It consists of well-defined mixtures of purified β-N-terminal glycated hemoglobin A and non-glycated hemoglobin A.

First, β-N-terminal glycated hemoglobin A and non-glycated hemoglobin A were isolated, purified to homogeneity, and characterised. The techniques used were cation exchange and affinity chromatography for the purification, and high performance liquid chromatography, capillary isoelectric focusing, electrospray ionisation mass spectrometry, and peptide mapping for the characterisation. Hemoglobins from blood of healthy, non-diabetic volunteers were obtained with a purity of >99.5% for non-glycated hemoglobin A and of >98.5% for β-N-terminal glycated hemoglobin A. However, results from peptide mapping indicate that the β-N-terminal glycated hemoglobin A preparations still contain some non-β-N-terminal glycated hemoglobins, co-eluting with β-N-terminal glycated hemoglobin A. The exact content of β-N-terminal glycated hemoglobin A in these preparations could be determined by a procedure consisting of standard addition, enzymatic cleavage and quantification of the resulting β-Nterminal peptides to be in the range from 95–97.5%.

Since the β-N-terminal glycated hemoglobin A and non-glycated hemoglobin A content could be exactly determined in the materials prepared, mixtures of both components could be successfully used to calibrate the candidate reference methods.
Urinary α1-Microglobulin Detects Uropathy. A Prospective Study in 483 Urological Patients
Authors: Everaert Karel , Delanghe Joris , Wiele Christophe Vande , Hoebeke Piet , Dierckx Rudy A. , Clarysse Bart , Lameire Norbert , Oosterlinck Willem
Published: October 2004

Purpose: The aim of the study was to evaluate prospectively urinary α1-microglobulin as a marker of proximal tubular damage following acute pyelonephritis and outflow disease of the upper urinary tract in a urological population with minimal exclusion criteria. We also measured the urinary γ-glutamyltransferase activity, urinary albumin, urinary and serum creatinine, serum IgA and serum α1-microglobulin.

Patients and methods: We studied 483 urological patients (age: 1 to 92 years, 297 men, 186 women) excluding patients receiving nephrotoxic drugs, or suffering from type 1 diabetes or renal diseases. There were 141 patients with urinary tract infection but no fever, 36 patients with high fever of non-renal origin, 51 patients with acute pyelonephritis and 156 patients with outflow disease of the upper tract, and 99 patients were incluced in the reference population.

Results: For acute pyelonephritis, vesico-ureteral reflux, and ureteral obstruction, urinary α1-microglobulin had a sensitivity of 94%, 90% and 63% respectively and a specificity of 67%, 77% and 76%. The area under the curve of the receiver operator characteristic curve was significantly (p < 0.001) higher for urinary α1-microglobulin than for albumin or γ-glutamyltransferase activity. Unexpected positive results were found in acute prostatitis. The urinary α1-microglobulin was the only parameter which differentiated between acute prostatitis and pyelonephritis (p < 0.001). Creatinine clearance or age had little and gender had no influence on the urinary excretion of α1-microglobulin. Urine production rate significantly increases the urinary α1-microglobulin/creatinine ratio.

Conclusion: Our results suggest that the urinary α1-microglobulin/creatinine ratio is a diagnostically useful marker of tubular damage in acute pyelonephritis and vesico-ureteral reflux in the urological population. Following renal colic and chronic ureteral obstruction, a significant increase in urinary α1-microglobulin excretion was observed.
Short-Term Variability in the Concentration of Serum Interleukin-6 and Its Soluble Receptor in Subjectively Healthy Persons
Authors: Dugué Benoit , Leppänen Esa
Published: October 2004

The effects of the time of the day and breakfast on the outcome of interleukin-6 and its soluble receptor in serum were studied on 22 subjectively healthy volunteers. We collected blood specimens at 8.00 a.m. after an overnight fast, at 9.30 a.m. after usual breakfast, and at 11.30 a.m. A second group of volunteers (n = 20) was studied during the evening. We observed a significant decrease in the concentration of interleukin-6 after breakfast. This suggests that for assay of this analyte it is preferable to collect specimens after overnight fast. No changes were observed in the concentrations of interleukin-6 soluble receptor. Weak, but significant negative correlations were found between the age of the volunteers and the concentrations of interleukin-6 soluble receptor and between age and the ratio interleukin-6 soluble receptor/interleukin-6. The concentrations of interleukin-6 were positively and significantly correlated with age.

The within-subject variablity was 30 % for interleukin-6,13% for its receptor, and 33.1% for the ratio interleukin-6 soluble receptor/interleukin-6. The between-subject variability was 43.7 % for interleukin-6, 22.2% for its receptor, and 60.2 % for the ratio interleukin-6 soluble receptor/interleukin-6. The indices of individuality (ratio within-subject variability/between-subject variability) were calculated and found to be 0.69, 0.60, and 0.55 for interleukin-6, its soluble receptor, and the ratio interleukin-6 soluble receptor/interleukin-6, respectively. The implications of these indices with the use of health-related reference values is discussed.
Pediatric Reference Intervals for 34 Biochemical Analytes in Urban School Children and Adolescents
Authors: Jagarinec Nada , Flegar-Meštrić Zlata , Šurina Branka , Vrhovski-Hebrang Danijela , Preden-Kereković Vladimira
Published: October 2004

Concentrations of 34 biochemical constituents of sera were determined on 998 randomly selected urban school children and adolescents aged 8–18 years from Zagreb, Croatia. Reference intervals were obtained by using non-parametric methods to estimate 2.5 and 97.5 percentiles of distribution as upper and lower normal reference intervals, according to the IFCC recommendations. These were compared to reference intervals in the healthy adult population, aged 20–30 years from the same geographical area. Serum glucose, potassium, sodium, chloride, magnesium, iron, zinc, total serum proteins and electrophoretic fractions, and amylase, did not show age or sex differences; total serum bilirubin, total calcium, phosphate, high density lipoprotein cholesterol, total iron binding capacity, unsaturated iron binding capacity, copper, aspartate aminotransferase, alkaline phosphatase, cholinesterase, creatine kinase, and lactate dehydrogenase had higher reference intervals than the adult population. Urea, creatinine, urate, alanine aminotransferase, γ-glutamyltransferase, total cholesterol and low density lipoprotein-cholesterol, and triglycerides had lower reference intervals than the adult population.
Progress in Immunoassay Technology
Authors: Price Christopher P.
Published: October 2004

Immunoassay is now the most
widely used analytical technique in laboratory medicine embracing a vast
repertoire of analytes and delivered through an increasingly diverse range of
devices. This explosion of analytical techniques is complemented by an
increasing knowledge base on the antigen antibody reaction that is being used to
explore new and improved methodologies.

Our knowledge of the molecular
chemistry of the antigen antibody reaction coupled with the molecular biology of
immunoglobulin expression has led to the development of antibody and
antibody-like molecules with enhanced specificity, and reaction kinetics. These
developments include novel fusion proteins, antibody mimics and antibodies that
recognise antigen antibody complexes.

The advances in the chemistry of
the analytical systems are matched by the design of delivery vehicles: on the
one hand the automated analyser that facilitates the analysis of large numbers
of samples and on the other, the encapsulated, miniaturised device that enables
an immunoassay to be performed at the point of care.
Engineering of an Anti-Steroid Antibody: Amino Acid Substitutions Change Antibody Fine Specificity from Cortisol Estradiol
Authors: Chames Patrick , Baty Daniel
Published: October 2004

Immunoassays are widely used for determination of the concentration of steroid hormones. However, obtaining specific anti-steroid monoclonal antibodies remains difficult. We used antibody engineering and phage display methods to change the specificity of an anti-cortisol monoclonal antibody towards estradiol. This work demonstrates that production of recombinant antibodies may be a valuable way of obtaining the high-specificity antibodies required for steroid immunoassays.
Peptide Models of Immunological Recognition: Paratope Dissection by Multiple Peptide Synthesis
Authors: Laune Daniel , Pau Bernard , Granier Claude
Published: October 2004

New approaches to obtain
information about the residues of the antibody paratope involved in the
interaction with antigen would be very useful to help perform rational
mutagenesis of antibodies for improving sensitivity or selectivity in
immunoassays. We have evaluated the possibility of dissecting the antibody
paratope into large sets of short (12 residues) overlapping peptides to
determine the contribution of each peptide to antigen binding. Our results show
that the systematic analysis of the antigen-binding properties of heavy chain
variable segment and light chain variable segment derived peptides of HyHEL-5, a
model anti-lysozyme antibody, can be an experimental approach to the selection
of paratope-derived peptides with antigen-binding activity. Detailed analysis of
the contribution of each residue from each binding peptide permitted the
identification of residues contributing to antigen binding. Of the 38 residues
we identified, 22 corresponded to residues that had been shown by X-ray
crystallography to be at the interface between HyHEL-5 and lysozyme. The peptide
analysis we have developed is thus a way to map the subset of residues from the
antibody paratope involved in antigen recognition. The same peptide approach was
used to map the idiotope that an anti-idiotypic antibody recognized in the
paratope of its cognate antibody.
Remodeling of Glycoprotein and Carbohydrate Antigens
Authors: Ronin Catherine
Published: October 2004

Glycosylation is the most extensive of all
post-translational modifications in proteins. It has important functions in
their secretion, antigenicity and metabolic clearance through structural
polymorphism. In recent years, advances in recombinant DNA technology allowed
the production of recombinant therapeutic proteins, among which glycosylated
proteins displayed differences compared to their native counterparts, including
antigenic carbohydrates. In this review, we discuss the potential use of cloned
glycosyltransferases in remodeling recombinant glycoprotein antigens as well as
in synthesizing tumor-associated carbohydrate antigens.
Strongly Enhanced Serum Levels of Vascular Endothelial Growth Factor (VEGF) after Poly-trauma and Burn
Authors: Grad Sibylle , Ertel Wolfgang , Keel Marius , Infanger Manfred , Vonderschmitt Dieter J. , Maly Friedrich E.
Published: October 2004

Angiogenesis is a key component
of the repair mechanisms triggered by tissue injury. Vascular endothelial growth
factor (VEGF) is an important mediator of angiogenesis, as it acts directly and
specifically on endothelial cells. VEGF produced locally in regenerating tissue
may spill over into the systemic circulation, and measuring levels of
circulating VEGF may allow monitoring of angiogenesis. To determine whether
circulating VEGF is increased after severe injury, we measured concentrations of
VEGF in serial serum samples of 23 mechanical burn patients, 55 patients with
multiple trauma and 56 healthy normal controls, using a newly established ELISA
assay. In burn patients, serum VEGF was increased on day 1 (369.4 ± 88.0 pg/ml)
and on day 3 (452.0 ± 65.3 pg/ml), reached highest levels on day 14 (1809.5 ±
239.7 pg/ml) and was still elevated on day 21 post-burn (1339.8 ± 208.7 pg/ml)
(mean ± SEM, p<0.01), when compared with healthy controls (82.2 ± 10.8 pg/ml
(mean ± SEM)). Likewise, in trauma patients, serum VEGF showed a trend towards
elevated values on the day of admission (186.9 ± 43.9 pg/ml) and on day 3 after
injury (193.2 ± 62.1 pg/ml). Thereafter, serum VEGF increased further (day 7,
507.0 ± 114.7 pg/ml), peaked on day 14 (742.4 ± 151.8 pg/ml) and was still
elevated on day 21 after injury (693.1 ± 218.6 pg/ml (mean ± SEM, p<0.01)).
No significant correlation was observed between peak serum VEGF and initial
severity of mechanical (Injury Severity Score) or burn injury (percentage of
body surface burned). However, in both burn and trauma patients, the subgroup of
patients with uncomplicated healing showed significantly higher increases of
serum VEGF than the subgroup who developed severe complications during the
post-traumatic course, such as sepsis, adult respiratory distress syndrome or
multiple organ failure (p<0.05). Thus, markedly enhanced levels of serum VEGF
are present one to three weeks after trauma or burn injury. Further, occurrence
of severe complications during the post-traumatic period is associated with
lesser increases of serum VEGF.
Decrease in High Density Lipoprotein Cholesterol (HDL-C) Levels Following Gemfibrozil Therapy
Authors: Lacko Andras G. , Kudchodkar Bhalchandra J. , Loney Wayne W. , Clearfield Michael B. , Weis Stephen
Published: October 2004

This report represents the
continuation of our studies on the effects of gemfibrozil therapy on high
density lipoprotein cholesterol levels. Previously, we reported that despite an
impressive mean increase in high density lipoprotein cholesterol (20 %), the
response to 12 weeks of gemfibrozil therapy was highly variable. Accordingly,
out of the 27 subjects studied, five actually had lower high density lipoprotein
cholesterol at the conclusion of therapy compared to baseline values. The
changes observed in plasma lipids, combined with correlational relationships
suggest that the conversion of triglyceride rich lipoprotein components into
high density lipoprotein may be impaired in those subjects that respond poorly
or negatively to gemfibrozil therapy.
Reference Intervals for Serum Cystatin C and Serum Creatinine in Adults
Authors: Erlandsen Erland J. , Randers Else , Kristensen Jens H.
Published: October 2004

The aim of this study was to
establish reference intervals for cerum cystatin C and serum creatinine in
adults. Blood samples were collected from 270 healthy blood donors (135 men and
135 women between 20 and 65 years old with 15 men and 15 women in each
five-year-interval). Serum cystatin C was analyzed using an automated
particle-enhanced immunoassay (DAKO Cystatin C PET kit) on the Cobas Mira S
analyzer. Serum creatinine was analyzed using the Vitros Creatinine Slide, an
enzymatic method on the Vitros 950 chemistry analyzer. The calculated reference
intervals for serum cystatin C were 0.62–1.15 mg/l in women (median 0.84 mg/l,
range 0.56–1.29 mg/l) and 0.51–1.25 mg/l in men (median 0.87 mg/l, range
0.42–1.39 mg/l). The Mann-Whithey U-test revealed no gender-related difference
for cystatin C (p = 0.48). A common reference interval in women and men was
calculated to be 0.54–1.21 mg/l (median 0.85 mg/l, range 0.42–1.39 mg/l). The
non-parametric reference interval for serum creatinine was 57–95 μmol/l in women
(median 72 μmol/l, range 44–105 μmol/l) and 69–111 μmol/l in men (median
89μmol/l, range 58–123 μmol/l).
Concepts for a Model of Good Medical Laboratory Services
Authors: Haeckel Rainer , Böhm Manfred , Capel Peter J. A. , Høiby Niels , Jansen Rob T. P. , Kallner Anders , Kelly Anne , Kruse-Jarres Jürgen D. , Küffer Hans , Libeer Jean Claude
Published: October 2004

Several international standards
and corresponding interpretation documents for quality management systems have
been published. Although these standards are found useful to some extent, they
are considered to be insufficient in several areas important for medical
laboratories particularly in the pre- and post-examinational phases. The
normative document for accreditation of laboratories (ISO/IEC Guide 25) is
presently being revised and a document for medical laboratories (ISO/TC 212, CD
15189) is at draft stage. Both aim to include aspects of total quality
management.

The concept of total quality
management is rather vague. Generally, its goal has been defined as "business
excellence". This term, however, needs some explanation if applied to medical
laboratories.

Therefore, a project group of the
European Confederation of Laboratory Medicine (ECLM) has developed a model for
total quality management, which is based on a comprehensive management concept
issued by the European Foundation for Quality Management. In the case of a
medical laboratory, the term "business excellence" should be replaced by "good
medical laboratory services". The proposed model could serve as a basis for
future developments of total quality management standards in laboratory
medicine. The goal of the "journey" should be clarified before it starts. To the
best of our knowledge, this is the first attempt to develop a model of a good
medical laboratory.
An ℋ︁∞algorithm for the windsurfer approach to adaptive robust control
Authors: Dehghani Arvin , Lanzon Alexander , Anderson Brian D. O.
Published: October 2004

The windsurfing approach to iterative control requires a series of controller designs with the gradual expanding of the closed‐loop bandwidth, and in the end in order to stop the algorithm, some validation tests are carried out. In this paper, an ℋ︁∞design algorithm is introduced in order to remove the empirical aspect from the stopping criteria and to make the procedure more systematic, hence facilitating the design. Moreover, some restrictive assumptions on the plant model are lifted and some issues with the controller design step are tackled by the introduction of a new design method. This enables us to address a wider class of practical problems. Copyright © 2004 John Wiley & Sons, Ltd.
Gradient approximations in iterative feedback tuning for multivariable processes
Authors: Jansson Henrik , Hjalmarsson Håkan
Published: October 2004

Iterative feedback tuning (IFT) is a model free control tuning method using closed‐loop experiments. For single‐input single‐output (SISO) systems only 2 or 3, depending on the controller structure, closed‐loop experiments are required. However for multivariable systems the number of experiments increases to be proportional to the dimension of the controller. In this contribution several methods are proposed to reduce the experimental time by approximating the gradient of the cost function. One of these methods uses the same technique of shifting operators as is used in IFT for SISO systems. This method is further analysed and sufficient conditions for local convergence are derived. It is shown that even if there are commutation errors due to the approximation method, the numerical optimization may still converge to the true optimum. Copyright © 2004 John Wiley & Sons, Ltd.
Diffusivities of macromolecules in composite hydrogels
Authors: Kosto Kimberly B. , Deen William M.
Published: October 2004

Diffusivities of fluorescein‐labeled macromolecules were measured in dilute aqueous solution (D∞), agarose gels (Da), and agarose–dextran composite gels (D) using fluorescence recovery after photobleaching. Macromolecules with Stokes–Einstein radii (rs) ranging from 2.7 to 5.9 nm were used, including two globular proteins (ovalbumin and BSA) and three narrow fractions of Ficoll, a spherical polysaccharide. Gels with agarose volume fractions of 0.040 and 0.080 were studied with dextran volume fractions ranging from 0 to 0.0076 and 0 to 0.011, respectively. For both agarose concentrations, the Darcy permeability (κ) decreased by an order of magnitude as the dextran concentration in the gel was increased from zero to its maximum value. For a given gel composition, the relative diffusivity (D/D∞) decreased as rs increased, a hallmark of hindered diffusion. For a given test molecule, D/D∞ was lowest in the most concentrated gels, as expected. As the dextran concentration was increased to its maximum value, two‐ to threefold decreases in relative diffusivity resulted for both agarose gel concentrations. The reductions in macromolecular diffusivities caused by incorporating various amounts of dextran into agarose gels could be predicted fairly accurately from the measured decreases in κ, using an effective medium model. This suggests that one might be able to predict diffusivity variations in complex, multicomponent hydrogels (such as those in body tissue) in the same manner, provided that values of κ can be obtained. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2648–2658, 2004
Structuring under flow of suspensions in a gel
Authors: Jossic Laurent , Magnin Albert
Published: October 2004

Laminar flow of a suspension of spheres in a gelled fluid through a sudden expansion causes the suspended matter to become organized. Segregation and migration phenomena of mono and bi‐disperse suspensions have been highlighted. If different sizes of spheres and bimodal suspensions are used, this phenomenon can be used to form structured materials. Flow conditions are such that gravity effects and inertia are negligible. At rest, the spheres are stable in the gel. Nuclear magnetic resonance imaging was used to reveal the distribution of matter within the suspension downstream of the expansion. The interest of such structures for industrial applications is discussed. © 2004 American Institute of Chemical Engineers AIChE J, 50: 2691–2696, 2004
Partial trisomy of chromosome 10(q22–q24) due to maternal insertional translocation (15;10)
Authors: Han J.Y. , Kim K.H. , Jun H.J. , Je G.H. , Glotzbach C.D. , Shaffer L.G.
Published: October 2004

Interchromosomal insertional translocations are rare chromosome rearrangements with an incidence of about 1:80,000 live births. We report on the clinical and cytogenetic findings of a newborn baby with partial trisomy 10q22–10q24 due to a maternal insertional translocation 15;10. Partial trisomy of the long arm of chromosome 10 is a distinctive chromosome aberration characterized by prenatal‐onset growth retardation and craniofacial, skeletal, and other somatic anomalies. Most cases are unbalanced products from reciprocal chromosome translocations, and insertional translocations are rarely involved. The proband was initially referred because of severe intrauterine growth retardation, and fluorescence in situ hybridization (FISH) using painting probes confirmed the maternal balanced (15;10) insertion. © 2004 Wiley‐Liss, Inc.
Human body mass estimation: A comparison of “morphometric” and “mechanical” methods
Authors: Auerbach Benjamin M. , Ruff Christopher B.
Published: October 2004

In the past, body mass was reconstructed from hominin skeletal remains using both “mechanical” methods which rely on the support of body mass by weight‐bearing skeletal elements, and “morphometric” methods which reconstruct body mass through direct assessment of body size and shape. A previous comparison of two such techniques, using femoral head breadth (mechanical) and stature and bi‐iliac breadth (morphometric), indicated a good general correspondence between them (Ruff et al. [1997] Nature 387:173–176). However, the two techniques were never systematically compared across a large group of modern humans of diverse body form. This study incorporates skeletal measures taken from 1,173 Holocene adult individuals, representing diverse geographic origins, body sizes, and body shapes. Femoral head breadth, bi‐iliac breadth (after pelvic rearticulation), and long bone lengths were measured on each individual. Statures were estimated from long bone lengths using appropriate reference samples. Body masses were calculated using three available femoral head breadth (FH) formulae and the stature/bi‐iliac breadth (STBIB) formula, and compared. All methods yielded similar results. Correlations between FH estimates and STBIB estimates are 0.74–0.81. Slight differences in results between the three FH estimates can be attributed to sampling differences in the original reference samples, and in particular, the body‐size ranges included in those samples. There is no evidence for systematic differences in results due to differences in body proportions. Since the STBIB method was validated on other samples, and the FH methods produced similar estimates, this argues that either may be applied to skeletal remains with some confidence. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Fetal and infant head circumference sexual dimorphism in primates
Authors: Joffe Tracey H. , Tarantal Alice F. , Rice Karen , Leland Michelle , Oerke Ann‐Kathrin , Rodeck Charles , Geary Michael , Hindmarsh Peter , Wells Jonathan C.K. , Aiello Leslie C.
Published: October 2004

Studies have shown that after controlling for the effects of body size on brain size, the brains of adult humans, rhesus monkeys, and chimpanzees differ in relative size, where males have a greater volume of cerebral tissue than females. We assess whether head circumference sexual dimorphism is present during early development by evaluating sex differences in relative head circumference in living fetuses and infants within the first year of life. Head circumference is used as a proxy for brain size in the fetus and infant. Femur length is used as a proxy for body length in the fetus. Ultrasonography was used to obtain fetal measures, and anthropometry was used to obtain postnatal measures in humans, rhesus monkeys, baboons, and common marmosets. We show that statistically significant but low levels of head circumference sexual dimorphism are present in humans, rhesus monkeys, and baboons in early life. On average, males have head circumferences about 2% larger than females of comparable femur/body length in humans, rhesus monkeys, and baboons. No evidence for head circumference sexual dimorphism in the common marmoset was found. Dimorphism was present across all body size ranges. We suggest that head circumference sexual dimorphism emerges largely postnatally and increases throughout maturation, particularly in humans who reach adult dimorphism values greater than the monkeys. We suggest that brain dimorphism is not likely to impose an additional energetic burden to the gestating or lactating mother. Finally, some of the problems with ascribing functional significance to brain size sexual dimorphism are discussed, and the energetic implications for brain size sexual dimorphism in infancy are assessed. Am J Phys Anthropol, 2004. © 2004 Wiley‐Liss, Inc.
Strategien zur Erforschung neuer Reaktionen
Authors: Mukaiyama Teruaki
Published: October 2004

Dieser Aufsatz beschreibt anhand konkreter Beispiele die grundlegenden Konzepte, die sich in unserer Arbeitsgruppe über viele Jahre auf der Suche nach neuen chemischen Reaktionen bewährt haben. Unsere Strategie ist es, drei oder vier Themen gleichzeitig aufzugreifen, da wir es für wichtig erachten, möglichst viele Ergebnisse zu sammeln. Diese können zunächst ohne Bezug zueinander sein, sich aber später zu einer umfassenden Hypothese vereinigen. Drei Fallbeispiele aus unserer Forschung seien genannt: die 1960 entwickelte “oxidativ‐reduktive Kondensation”, die 40 Jahre später zum Einsatz von Verbindungen vom Typ Ph2POR als Reduktionsmittel führte; die “Aldolreaktion mit TiCl4” von 1973, aus der die heutige basenvermittelte Aldolreaktion entwickelt wurde; die “Glycosylierung durch Fluorzucker” von 1984, die seit kurzem für stereokontrollierte Glycosylierungen genutzt wird. Wie wir erkennen werden, vermittelt der kritische Rückblick auf geleistete Forschungen oft die Entwicklung neuer Ideen.
Explorations into New Reaction Chemistry
Authors: Mukaiyama Teruaki
Published: October 2004

This Review describes the basic concepts that have guided our exploration of new chemical reactions by giving examples of results from my research group. Our strategy of carrying out research is to investigate three to four different topics at a time so we can gather as many results as possible. These may at first appear unrelated to each other but may have the potential to be united into a greater hypothesis after repeated feedback. Three scenarios from our research are presented: the “oxidative–reductive condensation reaction” devised in 1960, which after an interval of nearly 40 years brought forth the new concept of using compounds of structure Ph2POR as reducing reagents; the “TiCl4‐aldol reaction” of 1973 that eventually led to the present “base‐promoted aldol reaction” through a chain of ideas; and the “glycosylation reaction using fluorosugars” from 1984 which recently bloomed into “stereocontrolled glycosylation”. Thus, it can be said that by reviewing what we had done before, we were able to expand on it to achieve new outcomes.
Superparamagnetic iron oxide particles: contrast media for magnetic resonance imaging
Authors: Lawaczeck Rüdiger , Menzel Michael , Pietsch Hubertus
Published: October 2004

The mainstream magnetic iron oxide particles used as contrast media for magnetic resonance (MR) imaging are composed of a magnetic iron oxide core surrounded by a dextran or carboxydextran coat. The core size ranges from 2 nm to less than 10 nm, and the hydrodynamic diameter ranges from 20 nm to about 120 nm. The coat prevents aggregation and sedimentation of the particles in aqueous solutions, achieves high biological tolerance, and prevents toxic side effects.

Two kinds of particles are considered: (i) large particles (>30 nm), called superparamagnetic iron oxide particles (SPIOs) for liver imaging; (ii) smaller particles (<30 nm hydrodynamic diameter), called ultrasmall SPIOs (USPIOs), e.g. for MR angiography.

To characterize the particles, Mössbauer spectra are presented for the two particle ensembles. These spectra allow insight into the magnetic coupling, the valency of the iron ions and a rough estimate of the core size to be deduced. On the basis of the concentration dependence of the MR signal intensities, two applications are discussed together with two representative clinical examples.

Future indications for MR diagnostics, e.g. the labeling and tracking of stem cells during stem‐cell therapy control, are outlined. Copyright © 2004 John Wiley & Sons, Ltd.
The microstructure of ferrofluids and their rheological properties
Authors: Pop L. M. , Hilljegerdes J. , Odenbach S. , Wiedenmann A.
Published: October 2004

One of the most important features of ferrofluids is the possibility to change their physical properties, especially their viscosity, by means of moderate magnetic fields. This capability makes ferrofluids very useful in the fields of engineering, medicine and fundamental research. Rheological experimental results, as well as theoretical studies, correlate the change of the viscosity of a sheared ferrofluid under the influence of a magnetic field, the so‐called magnetoviscous effect, to the internal structure formation under certain external conditions. To obtain information about the microstructure of ferrofluids, experiments using the small‐angle neutron scattering (SANS) technique have been carried out. Three magnetite‐based ferrofluids with different particle–particle interactions, and thus various magnitudes of the magnetoviscous effect, were investigated. Using a specially designed rheometer, SANS experiments were performed for different shear rates and magnetic field strengths in order to observe the modification of the microstructure in ferrofluids and to associate the SANS information with their macroscopical behaviour. The scattering patterns obtained show a good agreement with the qualitative model that explains the magnetoviscous effect. Copyright © 2004 John Wiley & Sons, Ltd.
Experiments with a ferrofluid‐supported linear electric motor
Authors: Engelmann Steffen , Nethe Arnim , Scholz Thomas , Stahlmann Hanns‐Dietrich
Published: October 2004

Inserting ferrofluids in the gap between the acting magnets of electrical machines will enlarge the forces or torques by reducing the magnetic resistance of the gap. Based on this effect, the efficiency of linear and rotating electric drives can be improved. The experimental setup to measure this force amplification in the case of a linear electric drive and the results are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Binding kinetics of magnetic nanoparticles on latex beads studied by magnetorelaxometry
Authors: Eberbeck D. , Bergemann Ch. , Hartwig S. , Steinhoff U. , Trahms L.
Published: October 2004

A system of magnetic nanoparticles (MNPs) and modified latex spheres was used serving as a model for studying binding reactions. The binding of MNPs on latex is estimated by the change of the magnetic relaxation properties of the MNP measured by a SQUID‐based magnetorelaxometry measurement system. By fitting of subsequently recorded relaxation curves, the kinetics of the binding reactions, i.e. the evolution of the fraction of bound MNPs, was extracted. The signal of bound MNPs scales linearly with the concentration of latex beads. For low latex concentrations the kinetics are described by a simple aggregation model, providing information about the density and probability of bindings to the target surface. Copyright © 2004 John Wiley & Sons, Ltd.
Study of the structure and stability of cobalt nanoparticles for ferrofluidic applications
Authors: Rudenkiy S. , Frerichs M. , Voigts F. , Maus‐Friedrichs W. , Kempter V. , Brinkmann R. , Matoussevitch N. , Brijoux W. , Bönnemann H. , Palina N. , Modrow H.
Published: October 2004

We present X‐ray absorption spectroscopy (XAS) data, ultraviolet photoelectron spectra (HeI) and metastable impact electron spectra (MIES) of cobalt nanoparticles (typically 4 to 10 nm), prepared by Co2(CO)8 thermolysis and pre‐stabilized by smooth oxidation. We find that the particles consist of a core–shell system with a dominantly f.c.c. core and a shell in which CoC and CoO coordination is likely to occur. This corresponds well to the results from electron spectroscopy, that stabilization occurs via formation of (CoCOx) and (CoO) groups formed during the oxidation procedure and appears sensitive to the reaction conditions. Peptization of the pre‐stabilized particles with KorantinSH surrounds the particles with a dense organic shell, stable up to about 250°C. The carbonic acid molecules of the shell are oriented predominantly perpendicular to the surface of the particles, their carboxyl functional group linking the shell with the cobalt particles. This result is also supported by the XAS data, where it is observed that, during peptization, CoC coordination is partly replaced by CoO coordination. In order to arrive at these statements, auxiliary measurements on bare and gas‐exposed cobalt films, also reported here, were required. Copyright © 2004 John Wiley & Sons, Ltd.
Simulation of a ferrofluid‐supported linear electrical machine
Authors: Nethe Arnim , Scholz Thomas , Stahlmann Hanns‐Dietrich
Published: October 2004

The force magnification of ferrofluids used in the airgap between the two acting magnets in electrical machines has been investigated with the theoretical method of orthogonal expansion. This theoretical substantiation is necessary for a comprehensive judgement of the measurements on a ferrofluid‐supported electric motor. The method itself and the results are presented. Copyright © 2004 John Wiley & Sons, Ltd.
Distribution of olfactory epithelium in the primate nasal cavity: Are microsmia and macrosmia valid morphological concepts?
Authors: Smith Timothy D. , Bhatnagar Kunwar P. , Tuladhar Praphul , Burrows Annie M.
Published: October 2004

The terms “microsmatic” and “macrosmatic” are used to compare species with greater versus lesser olfactory capabilities, such as carnivores compared to certain primates. These categories have been morphologically defined based on the size of olfactory bulb and surface area of olfactory epithelium in the nasal fossa. The present study examines assumptions regarding the morphological relationship of bony elements to the olfactory mucosa, the utility of olfactory epithelial surface area as a comparative measurement, and the utility of the microsmatic concept. We examined the distribution of olfactory neuroepithelium (OE) across the anteroposterior length of the nasal fossa (from the first completely enclosed cross‐section of the nasal fossa to the choanae) in the microsmatic marmoset (Callithrix jacchus) compared to four species of nocturnal strepsirrhines (Otolemur crassicaudatus, O. garnetti, Microcebus murinus, and Cheirogaleus medius). Adults of all species were examined and infant C. jacchus, O. crassicaudatus, M. murinus, and C. medius were also examined. All specimens were serially sectioned in the coronal plane and prepared for light microscopic study. Distribution of OE across all the turbinals, nasal septal surfaces, and accessory spaces of the nasal chamber was recorded for each specimen. The right nasal fossae of one adult C. jacchus and one neonatal M. murinus were also three‐dimensionally reconstructed using Scion Image software to reveal OE distribution. Findings showed OE to be distributed relatively more anteriorly in adult C. jacchus compared to strepsirrhines. It was also distributed more anteriorly along the nasal septal walls and recesses in neonates than adults. Our findings also showed that OE surface area was not a reliable proxy for receptor neuron numbers due to differing OE thickness among species. Such results indicate that nasal cavity morphology must be carefully reconsidered regarding traditional functional roles (olfaction versus air conditioning) assigned to various nasal cavity structures. At present, the microsmatic concept itself lacks a basis in nasal chamber morphology, since OE may have varying patterns of distribution among different primates. © 2004 Wiley‐Liss, Inc.
SB‐236057: Critical window of sensitivity study and embryopathy of a potent musculoskeletal teratogen
Authors: Augustine‐Rauch Karen A. , Zhang Qin J. , Posobiec Lorraine , Mirabile Rosanna , DeBoer Lisa S. , Solomon Howard M. , Wier Patrick J.
Published: October 2004

BACKGROUND

SB‐236057 is a potent skeletal teratogen in rodents and rabbits. The study objective was to identify the critical developmental window of compound sensitivity and to characterize the early onset of SB‐236057 embryopathy.

METHODS

SB‐236057 was orally administered to Sprague Dawley dams at 100 mg/kg/day on days 6–7, 8–11, 12–14, or 15–17 postcoitus (pc). The critical window of sensitivity was identified to occur between days 8–11 pc. Dams were then dosed on days 8–11 pc and embryos were evaluated by histochemical procedures on days 11, 13, or 15 pc.

RESULTS

Axial malformations were evident by day 11 pc. Analysis of the cartilaginous skeleton revealed missing posterior axial skeletal elements. However, only about one‐third of the malformed fetuses exhibited obvious rib and vertebrae abnormalities, and none of the affected fetuses exhibited abnormal appendicular skeletal elements. Expression pattern of sonic hedgehog in the notochord and floor plate was not affected, suggesting ventral midline signaling was not disrupted. Histological analysis demonstrated hypoplastic and/or missing musculature in proximity to the ribs and vertebrae. Caspase 3 analysis revealed no increases in apoptotic cells in the musculature. Confocal analysis of the limbs demonstrated truncated peripheral nerve formation and shortening of the appendicular musculature.

CONCLUSIONS

SB‐236057 is speculated to alter paraxial mesoderm programming. Many of the skeletal malformations may be caused secondarily from musculature abnormalities, suggesting that the myotome may be particularly sensitive to the compound. Furthermore, the finding that peripheral nerve trajectories were altered along the axis and in the limb suggests that SB‐236057 may alter early embryonic signaling pathways necessary for neuronal differentiation/axonal guidance that occur subsequently in embryo‐fetal development. Birth Defects Research (Part A), 2004. © 2004 Wiley‐Liss, Inc.
Unexpected distribution of immobilized microorganisms within alginate beads
Authors: Zohar‐Perez C. , Chet I. , Nussinovitch A.
Published: October 2004

Immobilization refers to the prevention of free cell movement by natural or artificial means. It has always been assumed that immediately after an immobilization procedure is performed, cells are distributed homogeneously in the beads that entrap them. However, in this study, Escherichia coli and Trichoderma asperellum distribution in alginate‐gel beads was found to be nonhomogenous. In fact, there was a greater presence of cells on the surface of the alginate beads than in their cores. © 2004 Wiley Periodicals, Inc.
A liquid chromatography–mass spectrometry method for the quantiﬁcation of both etoricoxib and valdecoxib in human plasma
Authors: Werner Ulrike , Werner Dierk , Hinz Burkhard , Lambrecht Christoph , Brune Kay
Published: October 2004

A practicable and selective liquid chromatography–mass spectrometry assay for the determination of two cyclooxygenase‐2 inhibitors, etoricoxib and valdecoxib, in human plasma is presented. The analytical technique is based on reversed‐phase high‐performance liquid chromatography (HPLC) coupled to atmospheric pressure chemical ionisation (APCI) mass spectrometry (Finnigan Mat LCQ ion trap). Mass analysis was performed in the positive ion mode. The ion trap was operated in the tandem MS mode (MS2) and the transitions of etoricoxib (m/z 359.2 → 280.3) and valdecoxib (m/z 315.1 → 235.1) were followed by selected reaction monitoring. Retention times of etoricoxib and valdecoxib were 1.05 and 1.08 min, respectively. The method was validated over a linear range 10–2500 and 5–1000 µg/L using the other substrate as internal standard. After validation, the method was used to study the pharmacokinetic proﬁle of etoricoxib or valdecoxib in a healthy volunteer after administration of a single oral dose (valdecoxib, 20 mg; etoricoxib, 90 mg). The presented method was sufﬁcient to cover more than 90% of the area under the plasma concentration time curve. Copyright © 2004 John Wiley & Sons, Ltd.
Stabilization of Acrylic Esters
Authors: Becker H. , Vogel H.
Published: October 2004

Acrylic acid (AA) and its esters are monomers which can easily be polymerized. In order to avoid the unintentional polymerization during the manufacture and storage, the acrylic esters are stored under air‐atmosphere to which 15 ppm (g g–1) hydroquinone monomethylether (MeHQ) has been added. The consumption of the stabilizers, oxygen (O2) and MeHQ, play an important role in the prognosis of the stability of the monomers. In earlier works the O2/MeHQ‐consumption of acrylic acid during the inhibition period without radical‐starter‐addition was examined [1]. In this paper it could be shown that the examinations on acrylic acid are not transferable to different acrylic esters. The O2‐consumption rates in the acrylic esters are approximately ten times smaller than in acrylic acid, depending on temperature and monomer. The inhibition periods of the acrylic esters are about the factor ten greater in comparison to acrylic acid.

A correlation between the concentration of the C=C double bond in the esters and the O2‐consumption is possible with the measurements of the O2‐consumption in the different acrylic esters as a function of temperature. The O2‐consumption of any acrylic ester can be calculated in this way on the basis of the C=C double bond concentration. The same applies to the inhibition period (the time up to the start of the polymerization). An estimation of the stability is possible with these two parameters.
A Theoretical Approach to Pressure Drop across Cyclone Separators
Authors: Zhao B.
Published: October 2004

Based on investigation of the flow pattern in cyclone separators, a new theoretical model was developed for the prediction of pressure drop across cyclone separators. This model includes the effect of the geometrical dimensions and flow parameters, and assumes that the total pressure drop consists of four main partial pressure drops due to gas expansion at the separator entrance, wall friction within the separator, swirling motion of the gas, and gas flow through the outlet pipe. The availability of the method is verified by the comparison of calculated values with experimental data and with other models for different dimensions of cyclones.
Influence of Oxygen and Dissolved Inorganic Additives on the Removal of Gaseous Acetylaldehyde by Use of a Wetted‐Wall Corona Discharge Reactor
Authors: Faungnawakij K. , Sano N. , Yamamoto D. , Kanki T. , Charinpanitkul T. , Tanthapanichakoon W.
Published: October 2004

A cylindrical wetted‐wall corona discharge reactor was used for the removal of acetaldehyde in gas mixtures of N2 and O2. Gaseous acetaldehyde was removed from the gas stream by simultaneous absorption and gaseous corona reaction. The acetaldehyde absorbed in water, was decomposed by the aqueous radical, OH, produced by contact of the gas corona with the water film. There is an optimized oxygen concentration for the effective removal. When oxygen coexists in the gas mixture at 5 %, acetaldehyde was effectively removed, resulting in overall sustainable removal of acetaldehyde. However, an increase in oxygen concentration resulted in a decrease in the extent of removal, when the corona current was excessively high. This is due to corona‐induced turbulence broadening the residence time distribution of gas in the reaction zone. The decompositions of absorbed acetaldehyde and TOC in water were obviously affected by the varied oxygen concentrations. Acetaldehyde was not removed in the absence of oxygen. The dissolved inorganic additives, NaOH and HCl, strongly affected the acetaldehyde absorbability into water and subsequently, the decomposition rate of the absorbed acetaldehyde.
Kinetic Model of the Partial Oxidation of Propylene to Acrolein on Bi‐Mo‐Mixed Oxides
Authors: Drochner A. , Fehlings M. , König D. , Vogel H.
Published: October 2004

Today the only industrial scale method of production for acrolein is by gaseous phase oxidation of propylene with air oxygen. Since the discovery of Bi‐Mo‐mixed oxides as oxidation catalysts this reaction can be performed with high selectivity and high conversionrates. A kinetic model is introduced to assist in mathematically describing the stationary concentration/time‐dependencies.
Oxidation of CS2 by AsBr4+: The Unexpected Formation of the Simple CS2Br3+ Carbenium Ion
Authors: Gonsior Marcin , Krossing Ingo
Published: October 2004

During the preparation of AsBr4+[Al(OR)4]−, the novel carbocation CS2Br3+ was synthesized by reaction of AsBr3, Br2, CS2, and Ag[Al(OR)4] (R=C(CF3)3). CS2Br3+[Al(OR)4]− was characterized by its crystal structure, NMR and IR spectroscopy, and quantum chemical calculations (including COSMO solvation enthalpies). Additional experiments as well as the computed thermodynamics indicated two likely reaction pathways: Ag++2 Br2+CS2→CS2Br3++AgBr and the direct 4 e− oxidation reaction AsBr4++CS2→CS2Br3++1/6As6Br6. Both reactions were observed experimentally and were calculated to be exergonic in solution by −226 and −56 kJ mol−1 respectively. As a result of charge delocalization the CS and CBr distances in the cation are shortened by 0.06 to 0.08 Å; the SBr distances are also slightly shortened indicating a delocalization of the charge also to the bromine atoms in the (S)Br moieties. Based on an analysis of the cation–anion contacts as well as quantum chemical MP2 calculations, a delocalization model as a planar 10 π electron system is discussed and the π molecular orbitals are given. It will be shown that the electronic situation of CS2Br3+ is very close to that in CBr3+, that is, the properties of SBr moieties and Br atoms as π donors towards a formal C+ center are comparable.