Паулиевское приближение для векторной частицы с аномальным магнитным моментом во внешнем кулоновском поле

Herein, a spin 1 particle with anomalous magnetic moment in an external Coulomb field is studied. We start with the relativistic tensor system of the Proca type in Cartesian coordinates. In these equations the Γ parameter is present related to an additional characteristic of the particle. In the case of an external magnetic field, it is interpreted as an anomalous magnetic moment. In the presence of an external electric field, additional interaction terms are presented as well; moreover, the terms of the first and second orders in parameter Γ appear. The case of an external Coulomb field is considered in detail. In the nonrelativistic approximation a Pauli type equation is obtained. In the nonrelativistic equation the separation of the variables with the use of spherical vectors is realized. One separate 2-nd order differential equation is found, in which additional interaction terms are missing. Besides, we derive systems of two coupled 2-nd order equations wherein linear and quadratic in parameter Γ interaction terms are presented. Previously, another approach was developed for analyzing the vector particle with anomalous magnetic moment. It was based on the use of tetrad formalism and separation of the variables in the Duffin – Kemmer equation with the help of the Wigner function. The nonrelativistic approximation was performed directly in the system of radial equations. Besides, previously formal Frobenius type solutions for an arising 4-th order differential equation were constructed; however, physically interpretable energy spectra were not found. We have proved that the radial equations derived by different methods are the same up to a simple liner transformation over two radial functions. In this paper, we have obtained a simpler 4-th order equation, the construction of Frobenius solutions becomes technically easier, but physical energy spectra are not found either.Исследуется частица со спином 1 и аномальным магнитным моментом во внешнем кулоновском поле. Исходной является релятивистская тензорная система уравнений типа Прока в декартовой системе координат. В этих уравнениях присутствует параметр Γ, связанный с дополнительной характеристикой частицы. В случае внешнего магнитного поля он интерпретируется как аномальный магнитный момент. Дополнительные члены взаимодействия появляются также и при наличии электрического поля, причем в этом случае есть члены первого и второго порядков по параметру Γ. Детально рассматривается случай внешнего кулоновского поля. Проведена процедура нерелятивистского приближения, получено уравнение паулиевского типа. В нерелятивистском уравнении проведено разделение переменных с использованием аппарата шаровых векторов. Получено одно отдельное радиальное уравнение второго порядка, в котором дополнительные члены взаимодействия отсутствуют. Кроме того, выведена система двух связанных уравнений второго порядка, в них присутствуют линейные и квадратичные по параметру Γ дополнительные члены взаимодействия. Ранее был развит другой подход к анализу векторной частицы с аномальным магнитным моментом, основанный на использовании тетрадного формализма и разделении переменных в уравнении Даффина – Кеммера с применением функций Вигнера, после чего процедура нерелятивистского приближения была выполнена непосредственно в радиальной системе уравнений. Были построены в явном виде формальные решения Фробениуса возникающего уравнения 4-го порядка, однако физически интерпретируемых спектров получить не удалось. Показано, что полученные разными методами нерелятивистские радиальные уравнения совпадают с точностью до простого линейного преобразования над двумя функциями. В настоящей работе получено более простое уравнение 4-го порядка, при этом построение решений Фробениуса технически проще, но найти физически интерпретируемые спектры также не удается

BRCA1 4153delA founder mutation in Russian ovarian cancer patients

The BRCA1 4153delA allele is frequently referred to as the Russian founder mutation, as it was initially detected in several cancer families from Moscow. Our earlier studies have demonstrated 1% occurrence of BRCA1 4153delA heterozygosity in familial and/or early-onset and/or bilateral Russian breast cancer (BC) patients. Since literature data suggest that the 4153delA variant is more associated with ovarian cancer (OC) than with BC, we expected to reveal a highly elevated frequency of this genotype in Russian ovarian cancer series. However, real-time allele-specific PCR genotyping has detected only two BRCA1 4153delA carriers out of 177 unselected OC patients (1.1%). Both these carriers were early-onset and had serous carcinomas of grade 3. Thus, our study supports neither the Russian origin of BRCA1 4153delA mutation, nor its selectivity towards ovarian versus breast cancer predisposition

High frequency of BRCA1, but not CHEK2 or NBS1 (NBN), founder mutations in Russian ovarian cancer patients

<p>Abstract</p> <p>Background</p> <p>A significant portion of ovarian cancer (OC) cases is caused by germ-line mutations in BRCA1 or BRCA2 genes. BRCA testing is cheap in populations with founder effect and therefore recommended for all patients with OC diagnosis. Recurrent mutations constitute the vast majority of BRCA defects in Russia, however their impact in OC morbidity has not been yet systematically studied. Furthermore, Russian population is characterized by a relatively high frequency of CHEK2 and NBS1 (NBN) heterozygotes, but it remains unclear whether these two genes contribute to the OC risk.</p> <p>Methods</p> <p>The study included 354 OC patients from 2 distinct, geographically remote regions (290 from North-Western Russia (St.-Petersburg) and 64 from the south of the country (Krasnodar)). DNA samples were tested by allele-specific PCR for the presence of 8 founder mutations (BRCA1 5382insC, BRCA1 4153delA, BRCA1 185delAG, BRCA1 300T>G, BRCA2 6174delT, CHEK2 1100delC, CHEK2 IVS2+1G>A, NBS1 657del5). In addition, literature data on the occurrence of BRCA1, BRCA2, CHEK2 and NBS1 mutations in non-selected ovarian cancer patients were reviewed.</p> <p>Results</p> <p>BRCA1 5382insC allele was detected in 28/290 (9.7%) OC cases from the North-West and 11/64 (17.2%) OC patients from the South of Russia. In addition, 4 BRCA1 185delAG, 2 BRCA1 4153delA, 1 BRCA2 6174delT, 2 CHEK2 1100delC and 1 NBS1 657del5 mutation were detected. 1 patient from Krasnodar was heterozygous for both BRCA1 5382insC and NBS1 657del5 variants.</p> <p>Conclusion</p> <p>Founder BRCA1 mutations, especially BRCA1 5382insC variant, are responsible for substantial share of OC morbidity in Russia, therefore DNA testing has to be considered for every OC patient of Russian origin. Taken together with literature data, this study does not support the contribution of CHEK2 in OC risk, while the role of NBS1 heterozygosity may require further clarification.</p

1,1 '-Diphenyl-bis-germatrane with persistent radical cation

International audienceBis-phenyl derivative of a novel family of bis-metallatranes, 1,1'-diphenyl-bis-germatrane, was synthesized and characterized. One-electron oxidation of this compound is electrochemically and chemically reversible providing a persistent radical cation

1,1'-Diphenyl-bis(silatrane) as the First Structurally Characterized bis(silatrane)

International audience1,1'-Diphenyl-bis(silatrane) (I) was obtained by the reaction of tris(1,3-dihydroxypropan-2-yl)amine (L) with PhSi(OEt)(3) in toluene. The molecular structure of complex I was established by X-ray diffraction (CIF file CCDC no. 2078347). Study of the redox properties of new bis(silatrane) I demonstrated that its radical ions generated by cyclic voltammetry are stable since the radical center located on the nitrogen atom is sterically protected within the bis(atrane) cage