Turbulence near cyclic fold bifurcations in birhythmic media

We show that at the onset of a cyclic fold bifurcation, a birhythmic medium composed of glycolytic oscillators displays turbulent dynamics. By computing the largest Lyapunov exponent, the spatial correlation function, and the average transient lifetime, we classify it as a weak turbulence with transient nature. Virtual heterogeneities generating unstable fast oscillations are the mechanism of the transient turbulence. In the presence of wavenumber instability, unstable oscillations can be reinjected leading to stationary turbulence. We also find similar turbulence in a cell cycle model. These findings suggest that weak turbulence may be universal in biochemical birhythmic media exhibiting cyclic fold bifurcations.Comment: 14 pages 10 figure

Partial characterization of dinoflagellate chromosomal proteins

Dinoflagellate chromosomal proteins were analyzed by acrylamide gel electrophoresis. The electrophoretic pattern of acid-insoluble chromosomal proteins from Gyrodinium cohnii in sodium dodecylsulfate gels is less heterogeneous than that of corn, and is characterized by a paucity of bands representing molecular weights below 43 000. Acrylamide gel electrophoresis of G. cohnii and Peridinium trochoideum acid-soluble chromosomal proteins in urea at pH 3.2 gives a banding pattern quite different than that of typical histones. Acid-soluble protein from chromatin prepared by the two different methods and from both organisms migrates as one predominant band with a mobility slightly less than that of Histone IV from corn. Its molecular weight, estimated by sodium dodecylsulfate gel electrophoresis, is about 16000. It is a basic protein (basic/acidic amino acids 1.3) but differs from most histones in that it contains both cysteine and aromatic amino acids and somewhat lower levels of basic amino acids (18 mole % compared with 22 to 30% for histones). In addition, the major acid-soluble component is present in chromatin from log-phase cells but absent in chromatin from stationary-phase cells. For these reasons, the major acid-soluble protein is probably not a histone.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22353/1/0000799.pd

Physarum nitric oxide synthases: genomic structures and enzymology of recombinant proteins

Physarum polycephalum expresses two closely related, calcium-independent NOSs (nitric oxide synthases). In our previous work, we showed that both NOSs are induced during starvation and apparently play a functional role in sporulation. In the present study, we characterized the genomic structures of both Physarum NOSs, expressed both enzymes recombinantly in bacteria and characterized their biochemical properties. Whereas the overall genomic organization of Physarum NOS genes is comparable with various animal NOSs, none of the exon–intron boundaries are conserved. Recombinant expression of clones with various N-termini identified N-terminal amino acids essential for enzyme activity, but not required for haem binding or dimerization, and suggests the usage of non-AUG start codons for Physarum NOSs. Biochemical characterization of the two Physarum isoenzymes revealed different affinities for L-arginine, FMN and 6R-5,6,7,8-tetrahydro-L-biopterin

Clinical Trials in Head Injury

Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate signficant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63185/1/089771502753754037.pd

Nora Mohberg Papers, 1955-1958

Mohberg was a North Dakota author of historical fiction related to her Norwegian American family

CHEM 307 Chemical Science Foundations Laboratory

Course syllabus for CHEM 307 Chemical Science Foundations Laboratory Course description: Covers basic laboratory techniques as performed on a variety of samples. Illustrates fundamental chemical principles and environmental analysis through laboratory experiments. Designed for elementary education majors and for students requiring a general education physical science laboratory course

CHEM 544 Biochemistry Lecture

Course syllabus for CHEM 544 Biochemistry Lecture Course description: An introduction to the fundamentals of biochemistry, including chemistry of living organisms, structures of biomolecules, and a survey of metabolism

CHEM 307 Chemical Science Foundations Laboratory

Course syllabus for CHEM 307 Chemical Science Foundations Laboratory Course description: Covers basic laboratory techniques as performed on a variety of samples. Illustrates fundamental chemical principles and environmental analysis through laboratory experiments. Designed for elementary education majors and for students requiring a general education physical science laboratory course