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20 results on '"Dougherty, S. T."'

1. Z2Z4-Additive Cyclic Codes: Kernel and Rank

Author

Borges, J., Dougherty, S. T., Fernández-Córdoba, C., and Ten-Valls, R.

Subjects
Computer Science - Information Theory
Abstract

A Z2Z4-additive code C subset of Z_2^alpha x Z_4^beta is called cyclic if the set of coordinates can be partitioned into two subsets, the set of Z_2 and the set of Z_4 coordinates, such that any cyclic shift of the coordinates of both subsets leaves the code invariant. Let Phi(C) be the binary Gray image of C. We study the rank and the dimension of the kernel of a Z2Z4-additive cyclic code C, that is, the dimensions of the binary linear codes and ker(Phi(C)). We give upper and lower bounds for these parameters. It is known that the codes and ker(Phi(C)) are binary images of Z2Z4-additive codes R(C) and K(C), respectively. Moreover, we show that R(C) and K(C) are also cyclic and we determine the generator polynomials of these codes in terms of the generator polynomials of the code C., Comment: arXiv admin note: text overlap with arXiv:1707.03214

Published
2017

2. Binary Images of Z2Z4-Additive Cyclic Codes

Author

Borges, J., Dougherty, S. T., Fernández-Córdoba, C., and Ten-Valls, R.

Subjects
Computer Science - Information Theory
Abstract

A Z2Z4-additive code C is called cyclic if the set of coordinates can be partitioned into two subsets, the set of Z_2 and the set of Z_4 coordinates, such that any cyclic shift of the coordinates of both subsets leaves the code invariant. We study the binary images of Z2Z4-additive cyclic codes. We determine all Z2Z4-additive cyclic codes with odd beta whose Gray images are linear binary codes.

Published
2017

3. Self-Dual Codes over Z_2xZ_4

Author

Borges, J., Dougherty, S. T., and Fernandez-Cordoba, C.

Subjects
Computer Science - Information Theory
Abstract

Self-dual codes over $\Z_2\times\Z_4$ are subgroups of $\Z_2^\alpha \times\Z_4^\beta$ that are equal to their orthogonal under an inner-product that relates to the binary Hamming scheme. Three types of self-dual codes are defined. For each type, the possible values $\alpha,\beta$ such that there exist a code $\C\subseteq \Z_2^\alpha \times\Z_4^\beta$ are established. Moreover, the construction of a $\add$-linear code for each type and possible pair $(\alpha,\beta)$ is given. Finally, the standard techniques of invariant theory are applied to describe the weight enumerators for each type., Comment: Submitted to Designs, Codes and Cryptography

Published
2009

8. On Z2Z4-additive complementary dual codes and related LCD codes

Author

Benbelkacem, N., Dougherty, S. T., Fernández Córdoba, Cristina, Borges, J. (Joaquim), and Borges, J.

Subjects
Gray map, Algebra and Number Theory, Complementary dual, ZZ-additive codes, Applied Mathematics, LCD codes, Engineering(all), Computer Science::Other, Theoretical Computer Science
Abstract

Linear complementary dual codes were defined by Massey in 1992, and were used to give an optimum linear coding solution for the two user binary adder channel. In this paper, we define the analog of LCD codes over fields in the ambient space with mixed binary and quaternary alphabets. These codes are additive, in the sense that they are additive subgroups, rather than linear as they are not vector spaces over some finite field. We study the structure of these codes and we use the canonical Gray map from this space to the Hamming space to construct binary LCD codes in certain cases. We give examples of such binary LCD codes which are distance-optimal, i.e., they have the largest minimum distance among all binary LCD codes with the same length and dimension.

Published
2020

12. Adhesive interactions between alternatively spliced CD44 isoforms

Author

Droll, A, Dougherty, S T, Chiu, R K, Dirks, J F, McBride, W H, Cooper, D L, Dougherty, G J, and Department of Sciences

Subjects
Lymphoma, Fibrosarcoma, Research Support, Non-U.S. Gov't, Blotting, Western, Receptors, Lymphocyte Homing, Antibodies, Monoclonal, Gene Expression, Receptors, Cell Surface, Flow Cytometry, Transfection, Epithelium, Recombinant Proteins, Cell Line, Cercopithecus aethiops, Alternative Splicing, Mice, Hyaluronan Receptors, Cell Adhesion, Tumor Cells, Cultured, Journal Article, Animals, Humans, Leukemia, Erythroblastic, Acute, Carrier Proteins, Cell Aggregation
Abstract

Alternative splicing of a series of 10 contiguous exons present within the CD44 gene can generate a large number of differentially expressed CD44 isoforms that contain additional peptide sequences of varying length inserted into a single site within the extracellular domain of the molecule proximal to the membrane spanning domain. Although distinct functions have been ascribed to certain of these isoforms, the effect of particular inserted domains on the ligand-binding specificity of the CD44 molecule remains unclear. In the present study, we demonstrate that while CD44H, the major CD44 isoform expressed on resting hemopoietic cells, and CD44R1, an alternatively spliced isoform present on transformed epithelial cells and certain activated and/or malignant hemopoietic cell types, can both bind avidly to hyaluronan, only CD44R1 can promote homotypic cellular aggregation when expressed in the CD44-negative murine lymphoma cell line TIL1. Experiments in which TIL1 cells transduced with different CD44 isoforms were tested for their ability to adhere to one another or to COS7 cells transfected with CD44R1, indicated that CD44R1 can recognize and bind a common determinant present on both CD44H and CD44R1. Monoclonal antibody blocking studies suggest further, that the determinant recognized by CD44R1 is located in a region of the CD44 molecule distinct from that involved in hyaluronan binding.

Published
1995

16. Maximum distance separable codes over $$(\mathbb(Z)_4)$$ and $$(\mathbb(Z)_2 \times \mathbb(Z)_4)$$.

Author

Bilal, M., Borges, J., Dougherty, S. T., and Fernández-Córdoba, C.

Subjects
RINGS of integers, LINEAR algebra, BINARY number system, ABELIAN equations, ABELIAN semigroups, ABELIAN groups, CIPHER & telegraph codes, GRAY codes, POLYNOMIALS
Abstract

Known upper bounds on the minimum distance of codes over rings are applied to the case of $${\mathbb Z_{2}\mathbb Z_{4}}$$-additive codes, that is subgroups of $${\mathbb Z_{2}^{\alpha}\mathbb Z_{4}^{\beta}}$$. Two kinds of maximum distance separable codes are studied. We determine all possible parameters of these codes and characterize the codes in certain cases. The main results are also valid when α = 0, namely for quaternary linear codes. [ABSTRACT FROM AUTHOR]

Published
2011
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19. Protocol for a feasibility and early efficacy study of the Comprehensive Lifestyle Improvement Program for Prostate Cancer-2 (CLIPP2).

Author

Algotar AM, Kumar R, Babiker HM, Dougherty ST, Hsu CH, Chow HH, Smith TE, Marrero DG, Courneya KS, Abraham I, Ligibel JA, and Thomson CA

Abstract

Background: Although androgen deprivation therapy (ADT) for prostate cancer demonstrates improved overall and disease-free survival, it is associated with adverse effects such as obesity and metabolic syndrome that increase risk of cardiometabolic disease and diabetes type 2. ADT also leads to fatigue, depression and erectile dysfunction, which reduce quality of life (QoL). Lifestyle modification has shown promise in reducing obesity, metabolic syndrome and diabetes type 2 in other disease types. However, there is a paucity of data regarding the utility of lifestyle modification in men receiving ADT for prostate cancer., Methods: The primary aim of the Comprehensive Lifestyle Improvement Program for Prostate Cancer-2 (CLIPP2) is to test the feasibility of conducting a 24-week lifestyle modification intervention in men on ADT for prostate cancer. Additionally, it will also determine the effect of this intervention on weight loss, cardiometabolic markers (secondary aim and markers of interest: serum glucose, insulin resistance, hemoglobin A1C and lipid panel), and QoL (tertiary aim). The intervention will be delivered weekly via telephone for the first 10 weeks and bi-weekly for the remaining 14 weeks. Questionnaires and serum samples will be collected at baseline, week 12, and week 24. Anthropometric measurements will be collected at baseline, week 6, week 12, week 18 and week 24., Results: We hypothesize that the CLIPP2 intervention will produce a 7% weight loss that will result in improved markers associated with cardiometabolic disease and type 2 diabetes in the study population., Conclusion: Results will provide insight into the role of lifestyle modification in addressing ADT adverse effects as well as provide preliminary data to inform the development of future lifestyle interventions in this area., Trial Registration: NCT04228055 Clinicaltrials. gov., (© 2021 Published by Elsevier Inc.)

Published
2021
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20. Identification and characterization of CD44RC, a novel alternatively spliced soluble CD44 isoform that can potentiate the hyaluronan binding activity of cell surface CD44.

Author

Chiu RK, Carpenito C, Dougherty ST, Hayes GM, and Dougherty GJ

Subjects
Alternative Splicing, Amino Acid Sequence, Base Sequence, Cell Adhesion, Cell Line, Chondroitin Sulfates metabolism, Cloning, Molecular, Exons, Humans, Hyaluronan Receptors genetics, Models, Biological, Molecular Sequence Data, Protein Binding, Protein Isoforms, RNA, Messenger metabolism, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Tumor Cells, Cultured, Adjuvants, Immunologic metabolism, Hyaluronan Receptors chemistry, Hyaluronan Receptors metabolism, Hyaluronic Acid metabolism
Abstract

Soluble CD44 proteins generated by proteolytic cleavage or aberrant intron retention have been shown to antagonize the ligand binding activity of the corresponding cell surface receptor, inducing apoptosis and inhibiting tumor growth. Interestingly, such findings appear to contradict recent studies demonstrating a correlation between the presence of high levels of soluble CD44 in the serum of cancer patients and poor prognosis. In the present study, we report the cloning of a novel, naturally occurring, differentially expressed, soluble CD44 isoform, designated CD44RC, which, in contrast to previously described soluble CD44 proteins, can dramatically enhance the hyaluronan binding activity of cell surface CD44. Sequence analysis suggests that CD44RC is generated by an alternative splicing event in which the 3' end of CD44 exon 2 is spliced into an internal splice acceptor site present within exon 18, altering reading frame and giving rise to a soluble protein with a unique COOH terminus. Functional studies suggest that CD44RC enhances hyaluronan binding by adhering to chondroitin sulfate side-chains attached to cell surface CD44, generating a multivalent complex with increased avidity for hyaluronan.

Published
1999
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