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Quantum Cryptography:A Survey

admin — Sat, 14 Jun 2008 14:46:22 +0000

We survey some results in quantum cryptography. After a brief introduction toclassical cryptography, we provide the quantum-mechanical background needed to present somefundamental protocols from quantum cryptography. In particular, we review quantum key distributionvia the BB84 protocol and its security proof, as well as the related quantum bit commitment protocoland its proof of insecurity.

DAGMAR BRUSS　GABOR ERDELYI　TIM MEYER　TOBIAS RIEGE　JOERG ROTHE
Institut fuer Theoretische Physik, Heinrich-Heine-Universitaet Duesseldorf,40225 Duesseldorf, Germany
quantum bit commitment quantum cryptography quantum key distribution

Qualitative and quantitative analysis of cytologic assessment of astrocytoma, oligodendroglioma and oligoastrocytoma

admin — Wed, 02 Apr 2008 03:10:25 +0000

OBJECTIVE: To evaluate the usefulness of intraoperative cytology for differential diagnoses of astrocytoma, oligodendroglioma and oligoastrocytoma. STUDY DESIGN: Qualitative analysis of cytologic features of the 3 brain tumors was conducted using intraoperative touch or squash preparations that were stained with the Papanicolaou method, targeting the cellular density, cytoplasmic and nuclear profiles and blood vessel morphology. In addition, we attempted a computer-assisted image analysis of tumor cell nuclei and compared the results with qualitative observations. RESULTS: Astrocytomas were characterized by many fibrillary cytoplasmic processes and large, irregular nuclei. Oligodendrogliomas were characterized by small, round nuclei and a fine, delicate capillary network. In both tumors of a higher grade, anaplastic large nuclei and proliferating endothelial cells were noted. Oligoastrocytomas showed combined cytologic profiles of astrocytomas and oligodendrogliomas. Quantitative studies suggested thatnuclei of oligodendroglial tumors were significantly rounder than those of astrocytomas. In general, the quantitative results were consistent with the qualitative observations. CONCLUSION; Cytologic evaluation using touch or squash preparations is of great help for intraoperative differential diagnosis of astrocytoma, oligodendroglioma and oligoastrocytoma. Cytologic as well as histologic assessment should be conducted at the intraoperative diagnosis of these tumors.

Inagawa,H　Ishizawa,K　Hirose,T
Department of Pathology, Saitama Medical University, Saitama, Japan.

Adolescent　 Adult　 Aged　 Aged, 80 and over Astrocytoma Brain Neoplasms

Quantitative analysis of temporal and spatial variations of chondrocytebehavior in engineered cartilage during long-term culture

admin — Wed, 12 Mar 2008 01:18:33 +0000

Park,K; Min,BH; Han,DK; Hasty,K

Abstract In this work, we present the fact that chondrocyte activity differs inrelation to their position in an engineered cartilage construct. Chondrocytes from porcine articularcartilage were cultured in a monolayer. Then the cell/extracellular matrix (ECM) membrane waspeeled off and centrifuged into a three-dimensional (3D) pellet-type construct. Cultivated in astatic condition, the constructs were harvested at specific time intervals (1, 2, 3, and 5 weeks)and manually cored using a biopsy punch to separate the core from the remaining construct. Theresultant parts, core and peripheral remnant were thus obtained and subjected to analysisindividually. Cell density (10(6 )cells/cm(3)) of the core was significantly higher at 1 week thanthat of the periphery but this trend was reversed at later time points. Cell viability wasremarkably better in the peripheral tissue. Alcian blue staining of glycosaminoglycan (GAG) revealedan intense blue staining from the periphery, exhibiting a steep gradient in distribution of GAGconcentration. The gene expression ratio of collagen type II to I appeared to be more altered in theperiphery, possibly suggesting cell dedifferentiation, especially at later time points (>2 weeks).The mRNA levels of matrix metalloproteinase-1 (MMP-1) and MMP-13 remained in the normal range,whereas collagen type X expression was more significantly upregulated at the periphery. This studyshowed that chondrocyte behavior could be highly variable in the extent of their proliferation,differentiation and dedifferentiation, depending on their physical location within 3D engineeredcartilage construct.

Keywords Cartilage, Articular; Chondrocytes

Annals of Biomedical Engineering
0090-6964, Volume 35, Issue 3, 2007, Pages 3-428