Anisotropic phantoms for quantitative diffusion tensor imaging and fiber-tracking validation

Different fiber materials (hemp, linen, viscose rayon, polyamide and dyneema twine) were tested for their suitability as fiber phantoms for diffusion tensor imaging (DTI) calibration on clinical magnetic resonance imaging systems with common diffusion-weighted echo planar imaging sequences. Additionally, the potential for fiber tracking validation of these fiber phantoms was investigated. For phantom manufacturing the fibers were wound up into a bundle of parallel fibers enwrapped by plastic ribbon. The most homogenously distributed fractional anisotropy (FA) values (0.63 ± 0.10) were determined in the dyneema and polyamide (0.3 ± 0.1) fiber phantom. FA values in the viscose, linen and hemp bundles were at high variations (about 0.2 ± 0.10). The dispersion of the direction of the principal eigenvector in the polyamide and dyneema phantom was less than 7°, for the other fiber phantoms it was over 30°. Thus, the presented results may indicate that polyamide- and dyneema-based fiber phantoms provide the opportunity for verification and validation of DTI sequences on clinical scanner. Additionally, they can be applicable for testing the accuracy of fiber tracking algorithms. A strong parallel alignment of the fibers with a constant compression grade of the fiber bundles could be achieved by machine-made production. This could also provide highly reproducible diffusion properties within the anisotropic fiber phantoms. © 2008 Springer-Verlag

Electrochemical reduction of 1-phosphinyl-2-sulfonylethylenes and the ESR spectra of their anion radicals

1. In aprotic and limitedly protogenic media, electrochemical reduction takes place with the cleavage of the C-S bond (EEC mechanism) and in protogenic media with the hydrogenation of the C=C bond (ECE mechanism). 2. The SO2 group does not prevent the distribution of the spin density over the whole molecule. © 1981 Plenum Publishing Corporation

Amino-nitrile cleavage in the electrochemical reduction of hydeazones of aromatic aldehydes

1. Factors which determine the possibility of amino-nitrile cleavage of hydrazones on electrochemical reduction (ECR) include the basicity of the anionic product formed in the course of the ECR and the mobility of the aldehyde hydrogen which depends on the character of the electron polarization of the hydrazone fragment and the polarity of the N-N bond. 2. The primary action in amino-nitrile cleavage under conditions of ECR is the deprotonation of the azomethine fragment in the unreduced molecule by electrochemically generated strong base (anion or dianion). © 1988 Plenum Publishing Corporation

Electron transfer in nucleophilic vinyl substitution reactions involving bromovinyl sulfones

It was shown that the reaction of phosphorous hexaalkyltriamides with β-bromovinyl aryl sulfones proceeds via the step of electron transfer with the formation of ion-radicals. © 1982 Plenum Publishing Corporation

The Fundamental Study of Arima Bamboo Industry (2)

A chair conformation with an axial orientation of the phosphoryl or thiophosphoryl group is preferable for 2-dimethylamino-2-oxo- and-2-thiono-1,3,2-oxathiaphosphorinanes. The cis isomer of 2-dimethylamino-2-oxo-4-methyl-1,3,2-oxathiaphosphorinane has a similar structure with an equatorial orientation of the 4-methyl group, while the corresponding sulfide is characterized by a trans configuration with a reoriented positioning of the substituents attached to the phosphorus atom. © 1989 Plenum Publishing Corporation

Three-dimensional structures of phosphorus-containing heterocycles 50. 2-dimethylamino-2-oxo- and -2-thiono-1,3,2-oxathiaphosphorinanes

A chair conformation with an axial orientation of the phosphoryl or thiophosphoryl group is preferable for 2-dimethylamino-2-oxo- and-2-thiono-1,3,2-oxathiaphosphorinanes. The cis isomer of 2-dimethylamino-2-oxo-4-methyl-1,3,2-oxathiaphosphorinane has a similar structure with an equatorial orientation of the 4-methyl group, while the corresponding sulfide is characterized by a trans configuration with a reoriented positioning of the substituents attached to the phosphorus atom. © 1989 Plenum Publishing Corporation

BAIKAL experiment: status report

We review the present status of the Baikal Neutrino Project and present the results obtained with the deep underwater neutrino telescope NT-200.Comment: 4 pages, 3 figures. Presented at TAUP 2001 (7th international workshop on Topics in Astroparticle and Underground Physics), Sep. 2001, Laboratori Nazionali del Gran Sasso, Assergi, Ital

Цифровые световые технологии для управления поведением Galleria mellonella

The authors found out that the greater wax moth (Galleria mellonella) harmed bee colonies by destroying up to 30 percent of honey in a beehive. They studied the results of experiments on controlling its behavior using a developed automated microprocessor system that maintained optical radiation sources duration.(Research purpose) To develop light technologies using a microprocessor-based automated system that allows controlling Galleria mellonella behavior by realizing attractive optical radiation characteristics.(Materials and methods) Galleria mellonella behavior was controlled by an automated system that the authors worked out for maintaining the required duration of the experiment and optical radiation parameters. The ATmega328 microcontroller was chosen as the main element of the developed microprocessor automated system. The authors created a program for it using visual programming FLProg version 5.3.0.(Results and discussion) The authors found that, regardless of the experiment duration, Galleria mellonella butterflies prefered radiation with 400 nanometers wavelength.(Conclusions) The authors determined that radiation with 400 nanometers wavelength and 10 minutes duration was attractive. They showed the ability to control Galleria mellonella behavior, luring butterflies to a specific place in the beehive with comfortable spectrum parameters. An automated system for controlling the greater wax moth butterfly behavior was developed on ATmega328 microcontroller by implementing attractive optical radiation characteristics.Показали, что большая восковая моль (Galleria mellonella) наносит вред пчелиным семьям, уничтожая до 30 процентов меда в улье. Изучили результаты экспериментов по управлению ее поведением с помощью разработанной автоматизированной микропроцессорной системы, поддерживающей продолжительность работы источников оптического излучения.(Цель исследования) Разработать световые технологии с применением микропроцессорной автоматизированной системы, позволяющей управлять поведением бабочек большой восковой моли путем реализации привлекательных характеристик оптического излучения.(Материалы и методы) Управление поведением большой восковой моли осуществляли с помощью разработанной нами автоматизированной системы поддержания требуемой продолжительности опыта и параметров оптического излучения. Главным элементом разработанной микропроцессорной автоматизированной системы выбрали микроконтроллер ATmega328. Написали для него программу, используя визуальное программирование FLProg версии 5.3.0.(Результаты и обсуждение) Выявили, что вне зависимости от длительности опыта бабочки Galleria mellonella отдают предпочтение излучению с длиной волны 400 нанометров.(Выводы) Определили, что привлекательным оказалось излучение с длиной волны 400 нанометров продолжительностью 10 минут. Показали возможность управлять поведением Galleria mellonella, заманивая бабочек в определенное место в улье, где заданы комфортные параметры спектра. На микроконтроллере ATmega328 разработали автоматизированную систему управления поведением бабочек большой восковой моли путем реализации привлекательных характеристик оптического излучения

Anisotropic phantoms for quantitative diffusion tensor imaging and fiber-tracking validation

Different fiber materials (hemp, linen, viscose rayon, polyamide and dyneema twine) were tested for their suitability as fiber phantoms for diffusion tensor imaging (DTI) calibration on clinical magnetic resonance imaging systems with common diffusion-weighted echo planar imaging sequences. Additionally, the potential for fiber tracking validation of these fiber phantoms was investigated. For phantom manufacturing the fibers were wound up into a bundle of parallel fibers enwrapped by plastic ribbon. The most homogenously distributed fractional anisotropy (FA) values (0.63 ± 0.10) were determined in the dyneema and polyamide (0.3 ± 0.1) fiber phantom. FA values in the viscose, linen and hemp bundles were at high variations (about 0.2 ± 0.10). The dispersion of the direction of the principal eigenvector in the polyamide and dyneema phantom was less than 7°, for the other fiber phantoms it was over 30°. Thus, the presented results may indicate that polyamide- and dyneema-based fiber phantoms provide the opportunity for verification and validation of DTI sequences on clinical scanner. Additionally, they can be applicable for testing the accuracy of fiber tracking algorithms. A strong parallel alignment of the fibers with a constant compression grade of the fiber bundles could be achieved by machine-made production. This could also provide highly reproducible diffusion properties within the anisotropic fiber phantoms. © 2008 Springer-Verlag

Anisotropic phantoms for quantitative diffusion tensor imaging and fiber-tracking validation

Different fiber materials (hemp, linen, viscose rayon, polyamide and dyneema twine) were tested for their suitability as fiber phantoms for diffusion tensor imaging (DTI) calibration on clinical magnetic resonance imaging systems with common diffusion-weighted echo planar imaging sequences. Additionally, the potential for fiber tracking validation of these fiber phantoms was investigated. For phantom manufacturing the fibers were wound up into a bundle of parallel fibers enwrapped by plastic ribbon. The most homogenously distributed fractional anisotropy (FA) values (0.63 ± 0.10) were determined in the dyneema and polyamide (0.3 ± 0.1) fiber phantom. FA values in the viscose, linen and hemp bundles were at high variations (about 0.2 ± 0.10). The dispersion of the direction of the principal eigenvector in the polyamide and dyneema phantom was less than 7°, for the other fiber phantoms it was over 30°. Thus, the presented results may indicate that polyamide- and dyneema-based fiber phantoms provide the opportunity for verification and validation of DTI sequences on clinical scanner. Additionally, they can be applicable for testing the accuracy of fiber tracking algorithms. A strong parallel alignment of the fibers with a constant compression grade of the fiber bundles could be achieved by machine-made production. This could also provide highly reproducible diffusion properties within the anisotropic fiber phantoms. © 2008 Springer-Verlag