Search Results - (Author, Cooperation:J. A. Schwarz)

2013-01-26

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Awards and Prizes ; Computational Biology/*education ; Curriculum ; Fabaceae/genetics/physiology ; Genomics/*education ; Internet ; Polymorphism, Single Nucleotide ; *Problem-Based Learning ; Transcriptome ; *Universities

2013-12-20

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

Adolescent ; Adult ; Aged ; Autistic Disorder/*genetics ; Brain/abnormalities/anatomy & histology/metabolism ; Case-Control Studies ; Chromosome Deletion ; Chromosomes, Human/genetics ; Chromosomes, Human, Pair 15/genetics ; Cognition/*physiology ; DNA Copy Number Variations/*genetics ; Dyslexia/genetics ; Female ; Fertility/genetics ; *Genetic Predisposition to Disease ; Heterozygote ; Humans ; Iceland ; Learning Disorders/genetics ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neuropsychological Tests ; Phenotype ; Schizophrenia/*genetics ; Young Adult

1089-7550

AIP Digital Archive

Physics

1/f noise measurements have been performed on Al-Cu thin films, of varying grain size, which were also subjected to electromigration lifetime tests. The results indicate a strong grain size dependence of the 1/f noise magnitude in the films. Moreover there is a correlation between electromigration lifetimes and values of 1/f noise magnitude, suggesting that 1/f noise measurements could be used as a nondestructive alternative to traditional electromigration testing.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

A two-dimensional computer simulation of electromigration based on resistor networks is presented. The model utilizes a realistic grain structure generated by the Monte Carlo method and takes specific account of the local effects through which electromigration damage progresses. The dynamic evolution of the simulated thin film is governed by the local current and temperature distributions. The current distribution is calculated by superimposing a two-dimensional electrical network on the lattice whose nodes correspond to the particles in the lattice and the branches to interparticle bonds. The current distribution problem is solved by applying Kirchoff's rules on the resulting electrical network. The calculation of the temperature distribution in the lattice proceeds by discretizing the partial differential equation for heat conduction, with appropriate material parameters chosen for the lattice and its defects. The simulation was tested by applying it to common situations arising in experiments with real films. Specifically, the model successfully reproduces the expected grain size, linewidth and bamboo effects, the log-normal failure time distribution, and the relationship between current-density exponent and current density.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

To predict interconnect reliability, the mean time to failure, nature of failure time distribution, and the variance in the distribution at operating conditions must be known. The first two pieces of data can be obtained using the well-established mean time to failure technique. It is demonstrated the effect of temperature on the variance of the failure time distribution can be found from data obtained from temperature-ramp resistance analysis to characterize electromigration. The predicted variance is lowest at temperatures near where data were gathered, but the variance increases as the temperature approaches operating conditions.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Al–1%Si test stripes were subjected to life testing, and the resistance-versus-time behavior of individual conductors were collected for subsequent analysis. The failure times were log-normally distributed and the median time to failure decreased with increasing temperature. Analysis of the resistance-versus-time data was performed using the Avrami rate expression, R(t)=R0 exp[(Bt)n] proposed earlier by Rodbell, Rodriguez, and Ficalora [J. Appl. Phys. 61, 2844 (1987)]. It is found that values of the parameter n vary for identical conductors stressed under the same conditions. Thus the physical significance of this parameter with respect to identifying mechanisms of the rate-determining step is questionable. On the other hand, dramatic changes in the value of this parameter are observed over the temperature range of this study; this reflects changes in the growth geometry. It is suggested that such effects can be used to establish appropriate stressing conditions during life testing to avoid possible complications in the interpretation of the reliability data.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

Variations in time to failure data for electromigration processes have shown the importance to conductor design of factors that include composition, grain size, and passivation thickness. Traditionally, these variables have been studied separately. An understanding of the combined effects of these variables is necessary to design reliable conductors. Temperature-ramp resistance analysis to characterize electromigration (TRACE) has been applied to sample groups in which composition, passivation thickness, and grain size were varied. The results of these experiments provide the kinetic parameters for electromigration, and from these values, a calculation is proposed that allows an estimate of the conductors' resistance to electromigration. The results suggest that the predominant factor controlling electromigration rates is the passivation thickness.

Electronic Resource

1089-7550

AIP Digital Archive

Physics

The distributions of activation energies for electromigration damage in Al and Al-4%Cu thin-film interconnects were determined using temperature-ramp resistance analysis to characterize electromigration. The activation energies for the pure aluminum conductors are well represented by a normal distribution. It is noted that the normality of the distribution of activation energies can account for the log-normal distribution of failure times that has been observed. On the other hand, the population of activation energies for the Al-4%Cu conductors is composed of three subpopulations, each of which is well represented by a normal distribution. This deviation from the results obtained for the Al samples can account for variations from log normality that have been observed in failure time distributions, for aluminum-alloy interconnects. It is proposed that the origin of the subpopulations is the affect of copper on the grain-boundary transport of aluminum.

Electronic Resource

1749-6632

Blackwell Publishing Journal Backfiles 1879-2005

Natural Sciences in General

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Seven days of dosing with either 30 mg or 60 mg of lansoprazole were compared with placebo in a double-blind, randomized, three-way cross-over study in 12 male healthy volunteers. Twenty-four-hour intragastric pH was measured after 7 days of dosing with each regimen, as well as 3 and 7 days after the end of dosing. During dosing with placebo, intragastric pH was above 4 for a median of 51 minutes. pH values were significantly raised to above 4 for 8.45 and 8.33 hours on Day 7 of dosing with lansoprazole 30 and 60 mg, respectively, but returned to normal by the third day after stopping dosing. No clinically relevant influence on endocrine function (serum concentrations of insulin, aldosterone, testosterone, parathormone, glucagon, T3, T4, TSH, LH, FSH, STH. prolactin, circadian Cortisol profile, ACTH test) was observed. No serious adverse clinical or laboratory events were noted.

Electronic Resource

1365-2036

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Lansoprazole (AG 1749/CG 4801) is an inhibitor of gastric acid secretion by blocking H+,K+-ATPase. In this 2:1 randomized, double-blind, multicentre trial lansoprazole 30 mg am was compared to 40 mg famotidine nocte in 264 out-patients suffering from uncomplicated duodenal ulcer. After 2 weeks of treatment ulcer healing was confirmed endoscopically in a significantly higher proportion (P= 0.027) of patients treated with lansoprazole (94/174 = 54.0%) compared to patients receiving famotidine (35/90 = 38.9%). Cumulative healing rates after 4 weeks were 91.4% for the lansoprazole group and 83.3% for the famotidine group (P= 0.065). Pain relief and decrease of concomitant antacid consumption during treatment were comparable in both groups. Both compounds were well tolerated. Rates of recurrent duodenal ulcer in the 6 months after trial treatment were 45/158 (28.5%) after lansoprazole, and 18/69 (26.1%) after famotidine.

Electronic Resource

1572-8927

Affinity distribution ; nonaqueous potentiometric titration ; medium effect ; effectivity

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Abstract Potentiometric titration of six carboxylic acid analytes were measured in aqueous and semiaqueous solvents to determine the effect of the solvent composition on the dissociation constants of the acids. The analytes studied were monoprotic (formic acid, acetic acid), diprotic (maleic and succinic acid) and triprotic (1, 2, ranging in composition from 0 to 80% by volume dioxane. The methodology used to assess the acidity constants was deconvolution of the proton binding isotherm of each analyte in each of the solvents. The dissociation constants agreed with those reported in the literature for titration in water. In the presence of the organic component, correlations relating the acidity constants with properties of the media were also found. In particular, affinity distributions derived from potentiometric titration data were used to assess the solvent media for resolving dissociation constants of weak acids and bases.

Electronic Resource

1433-8580

Tolerance ; Immunoglobulin light chains ; Kappa chain subgroups ; Rabbits ; Toleranz ; Immunglobulin L-Ketten ; Kappa-Subgruppen ; Kaninchen

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung In 28 erwachsenen und neugeborenen Kaninchen wurden verschiedene Möglichkeiten der Toleranzinduktion gegen eine menschliche Immunglobulin L-Kette untersucht. Nach der Toleranzinduktion wurde durch nachfolgende Immunisierung mit einer Kappa-Kette einer anderen Subgruppe die Toleranz in erwachsenen Tieren schneller durchbrochen als bei Tieren, die in der Neugeborenenperiode das Tolerogen erhielten. Nach den vorliegenden Ergebnissen ist es nicht wahrscheinlich, daß allergische Reaktionen im Gefolge einer Immuntherapie mit spezifischen Antiseren durch vorherige Toleranzinduktion gegen diese Immunglobuline verhindert werden können.

Summary Different methods of tolerance induction against a human kappa light chain were examined in 28 adult and newborn rabbits. By subsequent immunization with a kappa-L-chain of another subgroup after tolerance induction, the state of tolerance was broken down faster in the adult rabbits than in rabbits injected with the tolerogen in the neonatal period. Judging from the present results it seems unlikely that allergical reactions, after immune therapy with specific antisera, can be prevented by previous induction of immunological tolerance against those immunoglobulins.

Electronic Resource

1432-1750

Pulmonary Amyloidosis ; Monoclonal Gammopathy

Springer Online Journal Archives 1860-2000

Medicine

Abstract Description of a case of diffuse pulmonary amyloidosis and benign monoclonal gammopathy in a 59-year-old woman. It was diagnosed by transbronchial lung biopsy. The patient was observed for three years. It has been reported [1–4] that multiple myelomatosis, M gradient in the serum or in the urine and Bence-Jones proteinuria can occur simultaneously with amyloidosis. Magnus-Levi 1931 [5] suspected the Bence-Jones protein was the fundamental component of amyloid. Glenneret al. [6] confirmed this supposition in 1970 by demonstrating the identity of purified proteins from amyloid tissue with the primary structure of human immunglobulin light chains. Pulmonary lesions were observed in monoclonal gammopathies [7] in pulmonary myeloma [8, 9, 10], multiple myelomatosis [11, 12, 13], lymphosarcoma [2], bronchial carcinoma [14, 15, 16] and lymphoid interstitial pneumonia [17]. Diffuse pulmonary amyloidosis, in contradistinction to tumor-simulating delimited deposits of amyloid in respiratory organs [18, 19], is extremely rare. We found only case reports [20, 21] in which the condition had been diagnosed post mortem.

Electronic Resource

1432-1440

Tolerance ; Immunoglobulin Light Chains ; Kappa Chain Subgroups ; Toleranz ; Immunglobulin-L-Ketten ; L-Kappa-Subgruppen

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Die variablen Teile menschlicher Immunglobulin-L-Ketten werden chemisch in drei Kappa- und vier Lambda-Subgruppen unterteilt. Eine serologische Typisierung ließ sich bisher mangels spezifischer Antiseren nicht durchführen. Die Herstellung subgruppenspezifischer Antiseren wurde mittels Toleranzinduktion gegen ein Protein einer Subgruppe und nachfolgender Immunisierung mit einem Protein einer anderen Subgruppe untersucht.

Summary The variable parts of human immunoglobulin-L-chains were chemically subdivided into 3 kappa and 4 lambda subgroups. A serological typing was impossible till today because of the lack of specific antisera. The production of subgroup-specific antisera was examined after tolerance induction against a kappa protein and subsequent immunization with a protein of an other subgroup.

Electronic Resource

1432-1440

Evolution ; ontogeny ; immune system ; autoimmune disease ; Ontogenese ; Immunsystem ; Autoimmunkrankheiten

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Die phylogenetische Entwicklung des Immunsystems läßt sich anhand des Stammbaumes der Vertebraten deutlich verfolgen. Bei den Urfischen entstanden nacheinander intestinale Lymphocytenaggregate, die Milz, der Thymus und die ersten Plasmazellen. Transplantate werden chronisch abgestoßen und Antikörper der IgM-Klasse gebildet. Das Erscheinen von „jugular bodies“ und intestinalen Plasmazellansammlungen bei den Amphibien geht einher mit akuter Transplantatverwerfung, der Bildung von IgG-Antikörpern mit größerer Affinität zum Antigen als die IgM-Antikörper und erstmals auch einem schwachen immunologischen Gedächtnis. Mit dem Auftreten keimzentrenhaltiger Lymphknoten bei den Reptil-Säugern erscheint ein ausgeprägtes immunologisches Erinnerungsvermögen. Das komplizierte lymphatische System der Vögel und Säugetiere ermöglicht schließlich durch zahlreiche lymphatische Filter und Lymphknoten in allen Regionen des Organismus einen optimalen Kontakt zwischen immunkompetenten Zellen und körperfremden Substanzen und Erregern. Die besondere Struktur der verschiedenen Immunglobulinklassen ist auf molekularer Ebene das Ergebnis von Genduplikationen, zufallsverteilten Punktmutationen und Deletionen verschiedener Primordialgene. Dabei begünstigte der Selektionsdruck im Verlauf der Evolution die Entwicklung multípler Gene für die variablen Bereiche gegenüber einer geringeren Anzahl an Genen für die konstanten Bereiche der Immunglobulinpolypeptidketten. Die einheitliche phylogenetische Entwicklung von der Stufe der Amphibien bis zu den Säugetieren sowie die fast identische ontogenetische Entwicklung des Immunsystems der höheren Säugetiere rechtfertigen es, tierexperimentelle Ergebnisse auf den Menschen zu übertragen und daraus prophylaktische und therapeutische Konsequenzen zu ziehen.

Summary The phylogenetic development of the immune system can be closely followed by the evolutionary tree of vertebrates. Primitive fishes were the first to develop one after another lymphocyte aggregations in the intestine, the spleen, the thymus and the first plasma cells. In these animals, tissue grafts were rejected chronically and antibodies of the IgM-class produced. The differentiation of jugular bodies and intestinal aggregations of plasma cells in amphibians parallels the ability to an acute rejection of grafts and the production of IgG antibodies of stronger affinity towards antigens than the IgM antibodies. On this level the first discrete evidence of an immunological memory can be found. In mammal-like reptiles the differentation of germinal centers in the lymph nodes is accompanied by a distinct immunological memory. Only the complex lymphatic system of birds and mammals is able to give an optimal contact between immunocompetent cells and various antigens by means of multiple lymphatic filters. The structural peculiarities of immunoglobulin chains are the results of gene duplications, random point mutations and deletions of different primordial genes. The development of multiple genes for the variable parts of the immunoglobulin polypeptide chains was favoured by selection pressure during the course of evolution, while a smaller number was sufficient for the constant parts. Since features in the development of the immune system during phylogeny from amphibians to mammals are almost identical with those during ontogeny in higher mammals, we are able to transfer results obtained in animal research to man, and thus prophylactical and therapeutical consequences can be derived.

Electronic Resource

1432-1440

Monomeric IgM ; Virushepatitis ; Chronic Persistent Hepatitis ; Chronic Aggressive Hepatitis ; Liver Cirrhosis ; Monomeres IgM ; chronisch persistierende Hepatitis ; chronisch aggressive Hepatitis ; Lebercirrhose

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Monomeres IgM, bisher nur bei lymphoproliferativen Autoimmun- und einigen Infektionserkrankungen sowie vereinzelt bei Lebercirrhosen beschrieben, ließ sich häufig bei akuter Virushepatitis und chronisch-aggressiver Hepatitis und seltener bei chronisch-persistierender Hepatitis nachweisen. Da das Auftreten von monomerem IgM bei chronisch-aggressiver Hepatitis mit dem nachweis verschiedener Autoantikörper korrelierte (ANA, SMA, RF), kann der 7S-IgM-Test als leicht meßbares zusätzliches Kriterium zur Diagnostik und Verlaufsbeobachtung chronischer Lebererkrankungen beitragen.

Summary Monomeric IgM could be found rather frequently in acute hepatitis and chronic aggressive hepatitis and occasionally also in chronic persistent hepatitis. Earlier it was reported in lymphoproliferative-, autoimmune diseases, some infectious diseases and in cirrhosis of the liver. The occurrence of monomeric IgM in chronic aggressive hepatitis correlates with the detection of several autoantibodies (ANA, SMA, RF). The 7S-IgM-test may be used as an easily measurable additional criterium for diagnosis and course of chronic liver diseases.

Electronic Resource

1432-1440

Waldenström's disease ; Cryoglobulin ; anti-nuclear Activity ; μ-Chain-Fragment ; M. Waldenström ; Kryoglobulin ; anti-nucleärer Antikörper ; μ-Kettenfragment

Springer Online Journal Archives 1860-2000

Medicine

Zusammenfassung Bei einem über 4 Jahre beobachteten Patienten entwickelte sich das klinische Bild eines M. Waldenström, wobei mehrere Osteolyseherde, präfinal eine Ausschwemmung pathologischer Lymphoidzellen und sog. Waldenströmzellen und eine pathologisch deformierte IgM-Präcipitationslinie in der Immunelektrophorese nachzuweisen waren. Das isolierte Makroglobulin erwies sich als ein IgM-kappa-Kryoglobulin mit antinucleärer Aktivität. Im Serum fanden sich verschiedene Autoantikörper sowie ein μ-Ketten-fragment. Letzteres wurde neben einer Immunglobulin-L-kappa-Kette und kompletten IgG-Molekülen auch im Urin ausgeschieden. Die breite Streuung der vorliegenden Symptomatik verdeutlicht die Variabilität des Erscheinungsbildes der Makroglobulinämie Waldenström innerhalb des Formenkreises paraproteinämischer Hämoblastosen.

Summary Starting with a pathological IgM-precipitate in immunoelectrophoresis during the last 4 years, a patient developed Waldenström's disease with several osteolytic lesions. In the terminal stage lymphoid and so called Waldenström's cells occurred in peripheral blood. The isolated macroglobulin behaved as a cryoglobulin with antinuclear activity. Besides different autoantibodies a μ-chain-fragment was found in serum. μ-chain-fragment and kappa-Bence-Jones-protein as well as complete IgG-molecules were also excreted in the urine. The various findings demonstrate the multiple aspects of Waldenström's disease within the group of immunocytic discrasia.

Electronic Resource

1612-1112

Inverse gas chromatography ; Activated carbons ; Gas solid dispersive and specific interactions ; Benzene derivatives

Springer Online Journal Archives 1860-2000

Chemistry and Pharmacology

Summary Surface properties of activated carbons and carbon fibers subjected to oxidation processes are investigated by means of inverse gas chromatography (IGC). A general correlation between surface density of acidic groups and the empirical parameter επ related to electron acceptor interactions is established. Model adsorbents based on benzene derivatives with known numbers of functional groups are also studied by IGC to examine the effect of surface geometry in relationship to the επ results from the carbons.

Electronic Resource

0192-8651

Computational Chemistry and Molecular Modeling ; Biochemistry

Wiley InterScience Backfile Collection 1832-2000

Chemistry and Pharmacology

Computer Science

It is well known that if the formation of hydrocarbons during Fischer-Tropsch synthesis occurs via the condensation polymerization mechanism, there is little hope for selectivity enhancement in the desired range of products. Recent data on low surface area model catalysts, where readsorption is unlikely, have shown that at low conversions, the product distribution obeys the condensation polymerization mechanism and the distribution of products is shifted to lower-molecular-weight hydrocarbons. We have used a computer simulation of the growth of hydrocarbon chains to obtain a picture of the catalyst surface under synthesis conditions. Such an approach could prove useful in distinguishing between various theoretical models. We have applied the simulation to compare the changes in selectivity when readsorption occurs and when it does not. The dynamic behavior of the reacting system which is obtained from the computer results has shown that selectivity to lower-molecular-weight hydrocarbons is a stronger function of the extent of reaction than the incorporation of readsorption into the chain growth mechanism.

2 Ill.

Electronic Resource