ABSTRACT
We consider two simple models, called "urn models," for a general N-ball, M-urn problem. These models find applications in the study of relaxation in glassy dynamics. We obtain exact analytical results in these two cases for the average relaxation time tau to reach the ground state. In model I we also obtain the functional dependence of tau for large N, and in model II we obtain an asymptotic (N-->infinity) dependence of tau as a function of the number of urns M.
ABSTRACT
By using tissue microdissection and polymerase chain reaction (PCR) techniques, we examined 85 prostate tumors that were paired with normal tissues from the same patients for allelic loss at 26 highly polymorphic microsatellite sequences, 21 spanning 8p and 5 localized to 8q. Sixty-four tumors (75%) demonstrated loss of at least one 8p locus. Separate distal and proximal regions of deletion were observed as well as an intervening, staggered breakpoint. A novel region of homozygous deletion of sequences at the D8S87 locus was detected both by multiplex PCR and by fluorescence in situ hybridization within this breakpoint region. These data suggest that a tumor-suppressor gene mapping to proximal 8p is deleted frequently and is likely to be important for tumorigenesis in prostate tumors.
Subject(s)
Chromosomes, Human, Pair 8/genetics , Genes, Tumor Suppressor/genetics , Prostatic Neoplasms/genetics , Adult , Aged , Biomarkers, Tumor/blood , Chromosome Deletion , Genetic Markers , Humans , Loss of Heterozygosity/genetics , Male , Middle Aged , Polymerase Chain Reaction , Prostate-Specific Antigen/blood , Prostatic Neoplasms/pathologySubject(s)
Chromosomes, Artificial, Yeast , DNA-Binding Proteins/genetics , Genes , Peroxidase/genetics , Transcription Factors/genetics , Base Sequence , Breast/chemistry , Breast Neoplasms/genetics , Chromosome Walking , Chromosomes, Human, Pair 17 , Female , Humans , Molecular Sequence Data , Multigene Family , Ovarian Neoplasms/genetics , Ovary/chemistry , Sequence Tagged Sites , Tripartite Motif Proteins , Ubiquitin-Protein LigasesABSTRACT
To investigate whether the expression of GLUT-4 is influenced by neurogenic factor(s) released from the nerve to the muscle, we measured GLUT-4 at different time points after sectioning the sciatic nerve at different locations in two groups of rats. Specifically, GLUT-4 was measured at 12, 24, and 48 h after severing the sciatic nerve. In one group of animals the muscles were left either with a short nerve stump attached to the muscle, or, in another group of animals, a long nerve stump remained attached to the muscle. In both groups of animals the contralateral limb served as a control. We examined GLUT-4 in the red (RG) and white gastrocnemius (WG), since the RG is highly responsive to denervation and the WG is quite resistant to denervation [L. A. Megeney, P.D. Neufer, G. L. Dohm, M. H. Tan, C. A. Blewtt, G. C. B. Elder, and A. Bonen. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E583-E593, 1993]. In the long nerve stump WG no change in GLUT-4 was observed at 12, 24, or 48 h after denervation (P > 0.05). In the short nerve stump WG, changes were not evident at 12 and 24 h (P > 0.05), but by 48 h a significant decrement (-12.7 +/- 6.7%) was observed (P < 0.05). GLUT-4 changes were only evident 48 h after denervation (-19.8 +/- 4.5%; P < 0.05) in the long nerve stump RG.(ABSTRACT TRUNCATED AT 250 WORDS)
Subject(s)
Gene Expression/physiology , Insulin/physiology , Monosaccharide Transport Proteins/biosynthesis , Muscle Denervation , Muscle Proteins , Muscles/innervation , Muscles/metabolism , Sciatic Nerve/physiology , Animals , Blotting, Western , Glucose Transporter Type 4 , Kinetics , Male , Monosaccharide Transport Proteins/analysis , Monosaccharide Transport Proteins/isolation & purification , Organ Specificity , Rats , Rats, Sprague-Dawley , Reference Values , Time FactorsABSTRACT
A new semianalytical method to calculate the proximity function for electrons is proposed. An integral equation for the proximity function that can be solved by using information on the spatial dose distributions is obtained. The proximity function for electrons in the energy range from 10 eV to 10 keV is calculated by solving the equation numerically, using a set of electron collision cross sections for water vapor. The results are in good agreement with those obtained using the Monte Carlo method. The proposed method can be used for electrons of high energies much more efficiently than the Monte Carlo method.
Subject(s)
Electrons , Mathematics , Models, Theoretical , Radiation EffectsSubject(s)
Air Pollution, Radioactive , Lung , Respiration , Humans , Mathematics , Models, Biological , Radiation DosageABSTRACT
Dose distributions as well as mean doses to cylindrical cavities of bone marrow on X-ray irradiation have been calculated using (a) Monte Carlo method and (b) a simplified straight line approximation method. The results are compared with earlier published ones. Point doses differ appreciably from the earlier results by as much as 40 percent at some points, whereas mean doses agree to within 10 percent for all the three methods.
