Polymer microstructure waveguides on various substrates for optical interconnection and communication

Planar polymer lightguides ofpoly-(methyl methacrylate) (PMMA) are doped with a UV sensitive material and an azo dye, sensitive for green or blue light (514, 488 nm) simultaneously. The UV-sensitive material is used for recording a permanent waveguide pattern while the azo dye is meant for a reversible light induced refractive index change. Although the azo dye is partly destroyed by the UV light and the photochemical reaction during waveguide formation, a light induced phase modulation in the guide is still possible in such bifunctional materials

Wavelength division demultiplexing in the near infrared using holographically processed polymer microstructure waveguides

A five-channel wavelength-division demultiplexer (WDDM) is demonstrated that is fabricated in polymer microstructure waveguides and operates over a 100-nm bandwidth centered at 750 nm in the near-IR. The device has a maximum diffraction efficiency of about 50 percent at 730 nm, a spectral bandwidth of about 15 nm, and effectively utilizes the large optical transparency of the photolime gelatin polymer material at laser diode wavelengths

Microthermometry of laser-heated Chinese hamster ovary cells and sperm cells

Microthermometric measurements on optically-trapped Chinese Hamster Ovary (CHO) cells and sperms cells are reported, using a non-invasive microfluorometric detection technique. Within an optical tweezer system that has been outfitted with a spectral fluorescence excitation and detection capability, the changes in temperature induced by the process of sample confinement by a focused laser beam has been quantified over micron-sized spatial regions of both motile and immotile cells. Our measurement technique is based on the use of environmentally sensitive fluorophores that can be incorporated into the cell membrane and used to sense local changes in temperature when the cell membrane is perturbed optically or via other environmental stress factors. Using a cw 1 .064 tm Nd:YAG laser for trapping CHO and human sperm cells, a temperature increase of -4°C per 100 mW laser power was observed. At this infrared wavelength, cellular heating as result of laser confinement appears to be mainly due to radiation absorption by water

Engineering: Cornell Quarterly, Vol.18, No.3 (Spring 1983-84): Key to New Technologies

IN THIS ISSUE: Submicron Structures: A Microcosm of Modern Engineering /2 Thomas E. Everhart ... Ultrasmall Features: Key to the Future Development of VLSI Technology /7 J. Peter Krusius ... Small-Scale Physics for Large-Scale Electronic Circuits /12 Jeffrey Frey ... Dry Processing: New Techniques for Etching Submicrometer Structures /16 Edward D. Wolf and Ilesanmi Adesida ... New Techniques for Growing Compound Semiconductors /20 Lester F. Eastman ... Microfabrication for Guided Wave Optics /28 Gregory J. Sonek and Joseph M. Ballantyne ... Superconductors in Microstructures /32 Robert A. Buhrman ... Multidisciplinary Research: Key to Progress at NRRFSS /37 ... Register /41 ... Faculty Publications /4

Neurodegeneration associated with genetic defects in phospholipase A2

OBJECTIVE: Mutations in the gene encoding phospholipase A2 group VI (PLA2G6) are associated with two childhood neurologic disorders: infantile neuroaxonal dystrophy (INAD) and idiopathic neurodegeneration with brain iron accumulation (NBIA). INAD is a severe progressive psychomotor disorder in which axonal spheroids are found in brain, spinal cord, and peripheral nerves. High globus pallidus iron is an inconsistent feature of INAD; however, it is a diagnostic criterion of NBIA, which describes a clinically and genetically heterogeneous group of disorders that share this hallmark feature. We sought to delineate the clinical, radiographic, pathologic, and genetic features of disease resulting from defective phospholipase A2. METHODS: We identified 56 patients clinically diagnosed with INAD and 23 with idiopathic NBIA and screened their DNA for PLA2G6 mutations. RESULTS: Eighty percent of patients with INAD had mutations in PLA2G6, whereas mutations were found in only 20\% of those with idiopathic NBIA. All patients with two null mutations had a more severe phenotype. On MRI, nearly all mutation-positive patients had cerebellar atrophy, and half showed brain iron accumulation. We observed Lewy bodies and neurofibrillary tangles in association with PLA2G6 mutations. CONCLUSION: Defects in phospholipase A2 lead to a range of phenotypes. PLA2G6 mutations are associated with nearly all cases of classic infantile neuroaxonal dystrophy but a minority of cases of idiopathic neurodegeneration with brain iron accumulation, and genotype correlates with phenotype. Cerebellar atrophy predicts which patients are likely to be mutation-positive. The neuropathologic changes that are caused by defective phospholipase A2 suggest a shared pathogenesis with both Parkinson and Alzheimer diseases

PLA2G6, encoding a phospholipase A(2), is mutated in neurodegenerative disorders with high brain iron

Neurodegenerative disorders with high brain iron include Parkinson disease, Alzheimer disease and several childhood genetic disorders categorized as neuroaxonal dystrophies. We mapped a locus for infantile neuroaxonal dystrophy (INAD) and neurodegeneration with brain iron accumulation (NBIA) to chromosome 22q12-q13 and identified mutations in PLA2G6, encoding a calcium-independent group VI phospholipase A2, in NBIA, INAD and the related Karak syndrome. This discovery implicates phospholipases in the pathogenesis of neurodegenerative disorders with iron dyshomeostasis