Fast and Mobile Cataract Detection by Applying Line Laser Eye Illumination

Cataract is observed when the eye lens becomes opaque. This condition causes blurred vision and is the main cause of blindness worldwide. Cataract diagnosis is usually performed during ophthalmologist examination using a slit lamp, which requires expertise, is expensive and bulky. In this study, we present a small handheld illumination setup for cataract detection. Ex-vivo porcine eyes are investigated to determine whether colored line lasers, 450 nm (blue), 520 nm (green) and 650 nm (red), which shine obliquely into the eye, are principally suited for detection of the Y shaped suture cataract and of cold cataract, respecting exposure limits of EU guideline 2006/25/EC. Camera images of the cataract exhibited good results under illumination with all line lasers. Observations with the physician’s eye led to an even better diagnosis of cataract. Generally, green laser light illumination was the best choice for cataract detection. With red laser light illumination it was also possible, but least suitable for this purpose. With this method, line lasers are a good choice for cataract identification, as cataract can be detected quickly and without much effort. This type of line laser illumination of the eye is safe and both types of cataract are detectable with all wavelengths. For the human eye, a further development of this system is conceivable

A Performance Comparison of Pulsed Plasma Thruster Electrode Configurations

Pulsed plasma thrusters are currently planned on two small satellite missions and proposed for a third. In these missions, the pulsed plasma thruster's unique characteristics will be used variously to provide propulsive attitude control, orbit raising, translation, and precision positioning. Pulsed plasma thrusters are attractive for small satellite applications because they are essentially stand alone devices which eliminate the need for toxic and/or distributed propellant systems. Pulsed plasma thrusters also operate at low power and over a wide power range without loss of performance. As part of the technical development required for the noted missions, an experimental program to optimize performance with respect to electrode configuration was undertaken. One of the planned missions will use pulsed plasma thrusters for orbit raising requiring relatively high thrust and previously tested configurations did not provide this. Also, higher capacitor energies were tested than previously tried for this mission. Multiple configurations were tested and a final configuration was selected for flight hardware development. This paper describes the results of the electrode optimization in detail

pitfalls of ester linkage

In this study, dendritic polyglycerol sulfate (dPGS) is evaluated as a delivery platform for the anticancer, tubulin-binding drug paclitaxel (PTX). The conjugation of PTX to dPGS is conducted via a labile ester linkage. A non- sulfated dendritic polyglycerol (dPG) is used as a control, and the labeling with an indocarbocyanine dye (ICC) renders multifunctional conjugates that can be monitored by fluorescence microscopy. The conjugates are characterized by 1H NMR, UV-vis measurements, and RP-HPLC. In vitro cytotoxicity of PTX and dendritic conjugates is evaluated using A549 and A431 cell lines, showing a reduced cytotoxic efficacy of the conjugates compared to PTX. The study of uptake kinetics reveals a linear, non saturable uptake in tumor cells for dPGS-PTX-ICC, while dPG-PTX-ICC is hardly taken up. Despite the marginal uptake of dPG-PTX-ICC, it prompts tubulin polymerization to a comparable extent as PTX. These observations suggest a fast ester hydrolysis and premature drug release, as confirmed by HPLC measurements in the presence of plasma enzyme

Direct Estimation of the Mitochondrial DNA Mutation Rate in Drosophila melanogaster

Mitochondrial DNA (mtDNA) variants are widely used in evolutionary genetics as markers for population history and to estimate divergence times among taxa. Inferences of species history are generally based on phylogenetic comparisons, which assume that molecular evolution is clock-like. Between-species comparisons have also been used to estimate the mutation rate, using sites that are thought to evolve neutrally. We directly estimated the mtDNA mutation rate by scanning the mitochondrial genome of Drosophila melanogaster lines that had undergone approximately 200 generations of spontaneous mutation accumulation (MA). We detected a total of 28 point mutations and eight insertion-deletion (indel) mutations, yielding an estimate for the single-nucleotide mutation rate of 6.2 × 10−8 per site per fly generation. Most mutations were heteroplasmic within a line, and their frequency distribution suggests that the effective number of mitochondrial genomes transmitted per female per generation is about 30. We observed repeated occurrences of some indel mutations, suggesting that indel mutational hotspots are common. Among the point mutations, there is a large excess of G→A mutations on the major strand (the sense strand for the majority of mitochondrial genes). These mutations tend to occur at nonsynonymous sites of protein-coding genes, and they are expected to be deleterious, so do not become fixed between species. The overall mtDNA mutation rate per base pair per fly generation in Drosophila is estimated to be about 10× higher than the nuclear mutation rate, but the mitochondrial major strand G→A mutation rate is about 70× higher than the nuclear rate. Silent sites are substantially more strongly biased towards A and T than nonsynonymous sites, consistent with the extreme mutation bias towards A+T. Strand-asymmetric mutation bias, coupled with selection to maintain specific nonsynonymous bases, therefore provides an explanation for the extreme base composition of the mitochondrial genome of Drosophila

Fragmentation of Molecules by Fast Ion Impact

Single ionization of simple molecules, e.g. H2, CO2, by fast charged particle impact has been studied using a reaction microscope. By measuring the momenta of the emitted electron and the recoil ionic fragment in coincidence, channel-selective low-energy electron spectra have been recorded. The experimental cross sections will be presented, compared with the predictions of state-of-the-art CDW-EIS calculations and discussed in terms of molecular effects such as (i) autoionization and predissociation channels, (ii) interference patterns resulting from the two-center geometry of the diatomic molecule, in analogy to Young\u27s double-slit experiment and (iii) dependence of the electron emission on the orientation of the molecular axis

Kinetic Energy Release Distributions for C⁺₂ Emission from Multiply Charged C₆₀ and C₇₀ Fullerenes

We present asystematic study of experimental kinetic energy release distributions for the asymmetric fission processes Cq+60 C(iq-1\u3c)+70+ C+2 and C q+70 C(q-1)+60+ C+ 2 for mother ions incharge states q 4-8 produced incollisions with slow highly charged ions. Somewhat to our surprise, we find that the KERD for asymmetric fission from Cq+60 are considerably wider and have larger most likely values than the Cq+70 distributions inthe corresponding charge states when q \u3e 4

Aspekte der Testgüte bei der Erfassung schulischer Kompetenzen von Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf

Im Beitrag wurde geprüft, inwieweit die im IQB-Ländervergleich 2011 in der Primarstufe eingesetzten Kompetenztests in Deutsch und Mathematik dazu geeignet sind, auch die Kompetenzen von Schülerinnen und Schülern mit sonderpädagogischem Förderbedarf (SPF) adäquat zu erfassen. Dazu wurden der Anteil fehlender Werte, die Passung des Raschmodells, differenzielle ltemfunktionalität und Korrelationen der Testwerte zwischen den Schülergruppen mit SPF in Förder- und Grundschulen und Kindern ohne SPF analysiert. Die eingesetzten Tests scheinen die schulischen Kompetenzen von Kindern mit SPF reliabel und valide zu erfassen. Allerdings zeigten sich Einschränkungen hinsichtlich der Vergleichbarkeit der Messungen für Kinder in Förderschulen in Mathematik. (DIPF/Orig.)In 2011, students with special educational needs (SEN) were part of the sample of the National Assessment Study (IQB-Ländervergleich 2011) in primary schools. The study examines if the achievement tests in German and Mathematics are also suited to assess SEN students\u27 proficiencies. To evaluate the structural validity of the achievement tests for SEN students in special education and regular schools, missing patterns, the fit of the Rasch model, differential item functioning, and correlations of the test scores were analyzed. Results show that the achievement tests captured the same proficiencies in similar ways for SEN students compared to students without SEN. However, comparability of the achievement tests in Mathematics was reduced for students in special education schools. (DIPF/Orig.

Two-Center Interference in p-H2 Electron-Transfer Collisions

We report on measurements of transfer excitation in collisions of 0.3-1.3 MeV protons with spatially oriented H2 molecules. Evidences of two center interference are found in the angular distribution of the molecule after a transfer excitation process and directly in the projectile angular scattering distributions. These features can be explained in a way which is analogous to that for the interferences in Young\u27s classical double slit experiment: The fast projectiles preferentially capture electrons close to either of the molecular nuclei, and thereby they change their momenta and de Broglie wavelengths. The waves emerging from the two \u27slits\u27 of the molecule interfere yielding the observed interference structure

Polyglycerol-based amphiphilic dendrons as potential siRNA carriers for in vivo applications

The development of nonviral synthetic vectors for clinical application of gene therapy using siRNA transfection technology is of particular importance for treatment of human diseases, which is yet an unsolved challenge. By employing a rational design approach, we have synthesized a set of well-defined, low- molecular-weight dendritic polyglycerol-based amphiphiles, which are decorated peripherally with the DAPMA (N,N-di-(3-aminopropyl)-N-(methyl)amine) moiety. The main differences that were introduced in the structural motif relate to dendron generation and the type of linker between the hydrophilic and hydrophobic segment. The synthesized amphiphiles were then characterized for their aggregation behaviour and further evaluated with respect to their siRNA transfection potential by comparing their physico-chemical and biological features. Our findings demonstrated that all four synthesized amphiphiles yielded high gene binding affinities. Furthermore, the ester-linked compounds (G1-Ester-DAPMA, G2-Ester-DAPMA) revealed noticeable gene silencing in vitro without affecting the cell viability in the tumor cell line 786-O. Remarkably, neither G1-Ester-DAPMA nor G2-Ester-DAPMA induced inflammatory side effects after systemic administration in vivo, which is noteworthy because such highly positively charged compounds are typically associated with toxicity concerns which in turn supports their prospective application for in vivo purposes. Therefore, we believe that these structures may serve as new promising alternatives for nonviral siRNA delivery systems and have great potential for further synthetic modifications