Diffraction due to a circular aperture.

Thesis (M.A.)--Boston UniversityDiffraction phenomena have been studied usually for the case when the aperture and other distances involved are large with respect to the wavelength. These treatments frequently have been based on Kirchhoff's formulation of Huygens' principle in which no attempt is made to satisfy Maxwell's equations or to satisfy the boundary conditions for the field vectors at the edge of the aperture. A rigorous treatment of the diffraction due to a circular aperture in an infinite conducting screen is not possible, but Bethe has developed an approximate method when the hole is small compared to the wavelength. Bethe's theory has been applied to the case of an incident plane wave (a) when the electric vector is parallel to the plane of incidence and (b) when the electric vector is perpendicular to the plane of incidence. Detailed calculations have been made in each case. The larger the wavelength for a given aperture or the smaller the aperture with respect to the wavelength, the more strongly will the radiation be concentrated toward the the axis. This concentration is more pronounced here than it would be in the optical region. [TRUNCATED

Sub-cycle time resolution of multi-photon momentum transfer in strong-field ionization

During multi-photon ionization of an atom it is well understood how the involved photons transfer their energy to the ion and the photoelectron. However, the transfer of the photon linear momentum is still not fully understood. Here, we present a time-resolved measurement of linear momentum transfer along the laser pulse propagation direction. Beyond the limit of the electric dipole approximation we observe a time-dependent momentum transfer. We can show that the time-averaged photon radiation pressure picture is not generally applicable and the linear momentum transfer to the photoelectron depends on the ionization time within the electromagnetic wave cycle using the attoclock technique. We can mostly explain the measured linear momentum transfer within a classical model for a free electron in a laser field. However, corrections are required due to the interaction of the outgoing photoelectron with the parent ion and due to the initial momentum when the electron appears in the continuum. The parent ion interaction induces a measurable negative attosecond time delay between the appearance in the continuum of the electron with minimal linear momentum transfer and the point in time with maximum ionization rate

Optical studies of 2-t-butyl-2-substituted biphenyls

Several 2-t-butyl-2'-substituted biphenyls have been prepared and resolved. The synthesis of these compounds was effected by heating with copper bronze a mixture of o-iodo-t-butylbenzene (or a derivative) and the appropriately substituted halogeno-benzene (or naphthalene) (Ullmann reaction). Large quantities of o-iodo-t-butylbenzene and methyl (or ethyl) 3-iodo-4-t-butylbenzoate have therefore been prepared. 6,6'-Di-t-butylbiphenyl-3"3lidicarboxylic acid was resolved through the brucine salt, and optically active 2,2'-di-t-butylbiphenyl has been obtained by decarboxylation of the optically active acid. 2',6 -Di-t-butylbiphenyl-3-carboxylic acid has been resolved through its strychnine salt and found to show high optical stability.An unsuccessful attempt was made to prepare 2,-nitro-6-t-butylbiphenyl-3-carboxylic acid, however, the synthesis of 2'-t-butyl-6-nitrobiphenyl-4-carboxylic acid succeeded and it was found that its strychnine salt underwent second-order asymmetric transformation in ethanol, and racemised in boiling chloroform solution. Racemisationof the optically active acid was studied at several temperatures between 51&deg; and 75&deg; and from the rates of racemisation the energy of activation was found to be 25.4 kcal.mole-1.Methyl 8-(2'-t-butylphenyl)-l-naphthoate was prepared by heating equimolecular proportions of0-iodo-t-butylbenzene and methyl 8-bromo-1-naphthoate.The acid obtained by hydrolysis of this ester was resolved through its strychnine salt, and racemisation of the optically active acid was studied. An attempt to prepare (2'-t-butylphenyl)-1-naphthalene from 8-(2'-t-butylphenyl)1-naphthoic acid by the Schmidt reaction resulted in the formation of the cyclisation product, 7-oxo-11-t-butylbenz[d e]anthracene. The benzanthracene obtained from the optically active acid was inactive.<p

Long-term restoration of alpha-L-iduronidase activity in fibroblasts from patients with mucopolysaccharidosis type I after non-viral gene transfer

Mucopolysaccharidosis type I (MPS I) is a lysosomal storage disorder due to deficiency of alpha-L-iduronidase (IDUA). Limitations such as need of weekly injection, high morbidity and mortality  and high cost of the current treatments show the need for new approaches to treat this disease. In this work we aimed to correct fibroblasts from a MPS I patient using non-viral gene therapy. Using a plasmid encoding the human IDUA cDNA, we achieved stable high IDUA levels in transfected fibroblasts up to 6 months of treatment. These results serve as proof-of concept that a non-viral approach can correct the enzyme deficiency in cells from lysosomal storage disorders patients, which can be used as a tool for research a series of disease aspects. Future studies will focus on verify if this approach can be useful in small animals and clinical trials

Monitoring des effektiven Pensionsantrittsalters 2011

Die umlagefinanzierte gesetzliche Pensionsversicherung stellt weiterhin die größte Säule der Pensionsvorsorge in Österreich dar, wobei sie aufgrund geänderter Rahmenbedingungen so angepasst werden muss, dass ihre langfristige Finanzierbarkeit erhalten bleibt. Ausgehend von der Frage, inwieweit eine nachhaltige Finanzierung durch Aufteilung auf die fünf im Gesetz genannten Steuerungsparameter (Antrittsalter, Bundesmittel, Beitragssatz, Pensionsanpassung, Steigerungsbetrag) überhaupt sinnvoll und möglich ist, gelangt die Kommission zur langfristigen Pensionssicherung zur Ansicht, das primäre Zielobjekt zur Steuerung sei die Anhebung des effektiven Pensionsantrittsalters. Der vorliegende Bericht stellt demnach ein valides und umfassendes Monitoring dieses Parameters dar. Ziel ist die Darstellung des Pensionsantrittsverhaltens im Jahr 2011 und insbesondere die gezielte Analyse des effektiven Pensionsantrittsalters, wobei ein Konnex zur demografischen Entwicklung und zur Erwerbsbeteiligung hergestellt wird

Commission des Communautes Europeennes: Groupe du Porte-Parole. Reunion de la Commission du mercredi 29 octobre 1980 = Commission of European Communities: Spokesman Group. Meeting of the Commission on Wednesday, 29 October 1980. Spokesman Service Note to National Offices Bio No. (80) 432, 30 October 1980

We study strong-field ionization and rescattering beyond the long-wavelength limit of the dipole approximation with elliptically polarized mid-IR laser pulses. Full three-dimensional photoelectron momentum distributions (PMDs) measured with velocity map imaging and tomographic reconstruction revealed an unexpected sharp ridge structure in the polarization plane (2018 Phys. Rev. A 97 013404). This thin line-shaped ridge structure for low-energy photoelectrons is correlated with the ellipticity-dependent asymmetry of the PMD along the beam propagation direction. The peak of the projection of the PMD onto the beam propagation axis is shifted from negative to positive values when the sharp ridge fades away with increasing ellipticity. With classical trajectory Monte Carlo simulations and analytical analysis, we study the underlying physics of this feature. The underlying physics is based on the interplay between the lateral drift of the ionized electron, the laser magnetic field induced drift in the laser propagation direction, and Coulomb focusing. To apply our observations to emerging techniques relying on strong-field ionization processes, including time-resolved holography and molecular imaging, we present a detailed classical trajectory-based analysis of our observations. The analysis leads to the explanation of the fine structure of the ridge and its non-dipole behavior upon rescattering while introducing restrictions on the ellipticity. These restrictions as well as the ionization and recollision phases provide additional observables to gain information on the timing of the ionization and recollision process and non-dipole properties of the ionization process.ISSN:1361-6455ISSN:0368-3508ISSN:0953-4075ISSN:0022-370

Simulations, measurements and optimization of OLEDs with scattering layer

A multi-scale optical model for organic light-emitting devices containing scattering layers is presented. This model describes the radiation of embedded oscillating dipoles and scattering from spherical particles. After successful model validation with experiments on a top-emitting white OLED, we show how this tool can be used for optimization with specific targets

Independent COL5A1 Variant in Cats with Ehlers-Danlos Syndrome

We investigated four cats with similar clinical skin-related signs strongly suggestive of Ehlers-Danlos syndrome (EDS). Cases no. 1 and 4 were unrelated and the remaining two cases, no. 2 and 3, were reportedly siblings. Histopathological changes were characterized by severely altered dermal collagen fibers. Transmission electron microscopy in one case demonstrated abnormalities in the collagen fibril organization and structure. The genomes of the two unrelated affected cats and one of the affected siblings were sequenced and individually compared to 54 feline control genomes. We searched for private protein changing variants in known human EDS candidate genes and identified three independent heterozygous COL5A1 variants. COL5A1 is a well-characterized candidate gene for classical EDS. It encodes the proα1 chain of type V collagen, which is needed for correct collagen fibril formation and the integrity of the skin. The identified variants in COL5A1 are c.112_118+15del or r.spl?, c.3514A>T or p.(Lys1172*), and c.3066del or p.(Gly1023Valfs*50) for cases no. 1, 2&3, and 4, respectively. They presumably all lead to nonsense-mediated mRNA decay, which results in haploinsufficiency of COL5A1 and causes the alterations of the connective tissue. The whole genome sequencing approach used in this study enables a refinement of the diagnosis for the affected cats as classical EDS. It further illustrates the potential of such experiments as a precision medicine approach in animals with inherited diseases