Modematching an optical quantum memory

We analyse the off-resonant Raman interaction of a single broadband photon, copropagating with a classical `control' pulse, with an atomic ensemble. It is shown that the classical electrodynamical structure of the interaction guarantees canonical evolution of the quantum mechanical field operators. This allows the interaction to be decomposed as a beamsplitter transformation between optical and material excitations on a mode-by-mode basis. A single, dominant modefunction describes the dynamics for arbitrary control pulse shapes. Complete transfer of the quantum state of the incident photon to a collective dark state within the ensemble can be achieved by shaping the control pulse so as to match the dominant mode to the temporal mode of the photon. Readout of the material excitation, back to the optical field, is considered in the context of the symmetry connecting the input and output modes. Finally, we show that the transverse spatial structure of the interaction is characterised by the same mode decomposition.Comment: 17 pages, 4 figures. Brief section added treating the transverse spatial structure of the memory interaction. Some references added. A few typos fixe

Модель гибридного ракетного двигателя. Вычисления, проект и испытания

На даний час і у майбутньому ракетні двигуни будуть найголовнішими засобами виводу на орбіту космічних транспортних апаратів. В даний час найважливішою вимогою при проектуванні двигуна ракети є зменшення її вартості і максимальне збільшення енерговіддачі. Проектування ракетних двигунів - довготривалий і трудомісткий процес, метою якого є виробництво дешевого і високоякісного двигуна, що має мінімальний вплив на навколишнє середовище. Слідуючи зазначеним вимогам, Варшавський Технологічний Університет спільно з Варшавським авіаційним Інститутом розпочали програму екологічно безпечного розвитку ракетних двигунів. Експериментальний гібридний двигун ракети був розроблений і виготовлений для перевірки нової формули твердого палива. Дана стаття містить дослідження безпечної роботи двигуна з окислювачем Al/AN/HTPB, використовуючи при цьому лабораторний дослідний стенд перевірки ракетного гібридного двигуна. Основна мета цієї роботи – це проектування простого ракетного двигуна з наступною можливістю його подальшого розвитку і поліпшення.Now and in the foreseeable future rocket engine will be the most basic propulsion of space vehicle. Nowadays the most important condition in design of rocket engine is the cost reduction and increasing thrust to weight ratio as much as possible. The design of rocket engines is exhaustive and difficult process. It must produce low cost and high performance engine with minimal influence on the environment. Following these requirements, Warsaw University of Technology jointly with Institute of Aviation in Warsaw, started their own program on ecologically safe propulsion development. The experimental hybrid rocket motor has been designed and manufactured to test a new formula of solid fuel. The paper explores the performance and safety implications associated with the oxidizer enhanced Al/AN/HTPB grain by using of a laboratory scale hybrid rocket motor test stand. The main objective of this work was to design simple rocket engine that could smoothly be developed and possibly improved in the future.На данный момент и в обозримом будущем ракетные двигатели будут самыми основными двигательными установками космических транспортных средств. В настоящее время самым важным условием при проектировании двигателя ракеты является уменьшение ее стоимости и максимальное увеличение соотношения тяги к весу. Проектирование ракетных двигателей – продолжительный и трудоемкий процесс, целью которого является производство дешевого и высококачественного двигателя с минимальным влиянием на окружающую среду. Следуя указанным требованиям, Варшавский Технологический Университет совместно с Варшавским авиационным институтом начали программу экологически безопасного развития ракетных двигательных установок. Экспериментальный гибридный двигатель ракеты был разработан и изготовлен для проверки новой формулы твердого топлива. Данная статья содержит исследования безопасной работы двигателя с окислителем Al/AN/HTPB, используя при этом лабораторный испытательный стенд проверок ракетного гибридного двигателя. Основная цель этой работы состоит в проектировании простого ракетного двигателя с последующей возможностью его дальнейшего развития и улучшения

Founder mutations in BRCA1 and BRCA2 genes

BRCA1 and BRCA2 germline mutations contribute to a significant number of familial and hereditary breast and/or ovarian cancers. The proportion of high-risk families with breast and/or ovarian cancer cases due to mutations in these tumor suppressor genes varies widely among populations. In some population, a wide spectrum of different mutations in both genes are present, whereas in other groups specific mutations in BRCA1 and BRCA2 have been reported with high frequency. Most of these mutations are prevalent in restricted populations as consequence of a founder effect. The comparison of haplotypes between families with the same mutation can distinguish whether high-frequency alleles derive from an older or more recent single mutational event or whether they have arisen independently more than once. Here, we review some of the most well-known and significant examples of founder mutations in BRCA genes found in European and non-European populations. In conclusion, the identification of the ethnic group of families undergoing genetic counseling enables the geneticist and oncologist to make more specific choices, leading to simplify the clinical approach to genetic testing carried out on members of high-risk families. Futhermore, the high frequency of founder mutations, allowing to analyze a large number of cases, might provide accurate information regarding their penetrance

BRCA1 genetic testing in 106 breast and ovarian cancer families from southern Italy (Sicily): a mutation analyses.

PURPOSE: To evaluate the contribution of germline BRCA1 mutations in the incidence of hereditary and familial Breast Cancer (BC) and/or Ovarian Cancer (OC) in patients from Southern Italy (in the region of Sicily) and to identify a possible association between the higher frequency of BRCA1 mutations and a specific familial profile. EXPERIMENTAL DESIGN: A consecutive series of 650 patients with BC and/or OC diagnosed between 1999 and 2005 were recruited from the Southern Italian region of Sicily, after interview at the "Regional Reference Centre for the Characterization and Genetic Screening of Hereditary Tumors" at the University of Palermo. Genetic counselling allowed us to recruit a total of 106 unrelated families affected with breast and/or ovarian cancer screened for mutations occurring in the whole BRCA1 gene by automatic direct sequencing. RESULTS: Germline BRCA1 mutations were found in 17 of 106 (16%) Sicilian families. The HBOC profile had a major frequency (66%) of mutations (P < 0.01). A total of 28 sequence variants was identified. Seven of these were pathogenic, 5 unknown biological variant (UV) and 16 polymorphisms. We also identified a pathological mutation (4843delC) as a possible Sicilian founder mutation. CONCLUSIONS: The present study is the first BRCA1 disease-associated mutations analysis in Southern Italian families. The early age of onset of such tumors and the association with the HBOC familial profile could be two valid screening factors for the identification of BRCA1 mutation carriers. Finally, we identified a BRCA1 mutation with a possible founder effec

TP53 mutations and S-phase fraction but not DNA-ploidy are independent prognostic indicators in laryngeal squamous cell carcinoma

To prospectively evaluate the prognostic significance of TP53, H-, K-, and N-Ras mutations, DNA-ploidy and S-phase fraction (SPF) in patients affected by locally advanced laryngeal squamous cell carcinoma (LSCC). Eight-one patients (median follow-up was 71 months) who underwent resective surgery for primary operable locally advanced LSCC were analyzed. Tumor DNA was screened for mutational analysis by PCR/SSCP and sequencing. DNA-ploidy and SPF were performed by flow cytometric analyses. Thirty-six patients (44%) had, at least, a mutation in the TP53 gene. Of them, 22% (8/36) had double mutations and 3% (1/36) had triple mutations. In total, 46 TP53 mutations were observed. The majority (41%) of these occur in exon 5 (19/46), while the mutations in exons 6, 7, and 8 were represented in 14, 7, and 6 patients, respectively (31% 15%, and 16%). Five LSCC patients (6%) showed a mutation in H-Ras gene. Sixty-three percent of the cases (51/81) were DNA aneuploidy, 14% of these (7/51) were multiclonal. Thirty-nine patients (48%) had an high SPF value. At Univariate analysis, the DNA aneuploidy, high SPF (> 15.1%), TP53 mutations and, in particular, the mutations that occur in exons 5 and 8 were significantly related to quicker disease relapse and short OS. At Multivariate analysis, the major significant predictors for both disease relapse and death were high SPF and any TP53 mutations. While histological grade G3 was an independent factor only for relapse. In conclusions, any TP53 mutations and high SPF are important biological indicators to predict the outcome of LSCC patients

TP53 and p16INK4A, but not H-KI-Ras, are involved in tumorigenesis and progression of pleomorphic adenomas.

The putative role of TP53 and p16INK4A tumor suppressor genes and Ras oncogenes in the development and progression of salivary gland neoplasias was studied in 28 cases of pleomorphic adenomas (PA), 4 cases of cystic adenocarcinomas, and 1 case of carcinoma ex-PA. Genetic and epigenetic alterations in the above genes were analyzed by Polymerase Chain Reaction/Single Strand Conformational Polymorphism (PCR/SSCP) and sequencing and by Methylation Specific-PCR (MS-PCR). Mutations in TP53 were found in 14% (4/28) of PAs and in 60% (3/5) of carcinomas. Mutations in H-Ras and K-Ras were identified in4%(1/28) and7% (2/28) of PAs, respectively. Only 20% (1/5) of carcinomas screened displayed mutations in K-Ras. p16INK4A promoter hypermethylation was found in 14% (4/28) of PAs and 100% (5/5) carcinomas. All genetic and epigenetic alterations were detected exclusively in the epithelial and transitional tumor components, and were absent in the mesenchymal parts. Our analysis suggests that TP53 mutations and p16INK4A promoter methylation, but not alterations in the H-Ras and K-Ras genes, might be involved in the malignant progression of PA into carcinoma. J. Cell. Physiol. 207: 654–659, 2006. 2006 Wiley-Liss, Inc

Towards high-speed optical quantum memories

Quantum memories, capable of controllably storing and releasing a photon, are a crucial component for quantum computers and quantum communications. So far, quantum memories have operated with bandwidths that limit data rates to MHz. Here we report the coherent storage and retrieval of sub-nanosecond low intensity light pulses with spectral bandwidths exceeding 1 GHz in cesium vapor. The novel memory interaction takes place via a far off-resonant two-photon transition in which the memory bandwidth is dynamically generated by a strong control field. This allows for an increase in data rates by a factor of almost 1000 compared to existing quantum memories. The memory works with a total efficiency of 15% and its coherence is demonstrated by directly interfering the stored and retrieved pulses. Coherence times in hot atomic vapors are on the order of microsecond - the expected storage time limit for this memory.Comment: 13 pages, 5 figure

Газометанный \ газокислородный ракетный двигатель. Проектирование и разработка

Хімічні ракетні двигуни – є і будуть у майбутньому найбільш широко використовуваними рушіями для транспортування на орбіту Землі. Інформаційна потреба технологій, постійно зростаюче число супутників, які необхідно виводити на орбіту змушує виробників ракетної техніки будувати двигуни з більш широким діапазоном тяги і кращою якістю роботи. З іншого боку, для мінімізації впливу на навколишнє середовище в космічній промисловості, передбачається використання екологічнобезпечних видів палива. Одним з видів палива, що є екологічнобезпечним і гарантує якісну роботу, є метан. Це паливо знаходиться в області інтересів всесвітньої ракетної галузі. Однак, на сьогоднішній день, лише кілька двигунів, що використовують метан пройшли повну перевірку, що вказує на широку область можливих удосконалень цієї техніки.Головна мета статті полягає в тому, щоб проаналізувати можливість використання метану як палива для ракетних двигунів. Авторами з використанням методів чисельної газової динаміки (CFD) проведені обчислення експериментального ракетного двигуна. Проведений аналіз є основою для проектування експериментального зразка. Експериментальне дослідження роботи нового двигуна проведено з метою підтвердження правильності обчислень. У майбутньому планується випробовування системи охолодження двигуна, що буде завершенням даного проекту.Chemical rocket engines are still and will be in the foreseeable future the most widely used means of propulsion systems in transportation into the earth's orbit. What is more, information technologies need more and more satellites constellations to be replenished. This forces the rocket industry to build rocket engines with wider range of thrust and better performance. On the other hand, in order to minimize the influence on the environment, ecologically-safe propellants are considered to be used in space industry [1]. One of propellants, which is ecologically-safe and guarantees good overall performance is methane. This fuel is in area of interests of world's rocket industry. However, till today only a few methane rocket engines were tested, so it seems to be a wide area of possible improvements in this field. The main aim of the paper will be to analyze the possibility of using methane as a fuel for the rocket engine. The authors made the computations of a model rocket engine, fueled by methane, using CFD method. The analysis stands as the basis for the design of a model rocket engine. Experimental research to check the calculations’ validity as well as testing of its cooling system will complete the design.Химические ракетные двигатели являются и будут в обозримом будущем, наиболее широко используемыми двигательными установками для транспортирования на орбиту Земли. Информационная потребность технологий, постоянно растущее число спутников, которые необходимо выводить на орбиту, вынуждает производителей ракетной техники строить двигатели с более широким диапазоном тяги и лучшим качеством работы. С другой стороны, для минимизации влияния на окружающую среду в космической промышленности, предполагается использование экологически безопасных видов топлива. Одним из видов топлива, которое является экологически-безопасным и гарантирует качественную работу, является метан. Это топливо находится в области интересов всемирной ракетной отрасли. Однако, на сегодняшний день, лишь несколько двигателей, использующих метан, прошли полную проверку, что указывает на широкую область возможных усовершенствований этой техники. Главная цель статьи состоит в том, чтобы проанализировать возможность использования метана как топлива для ракетных двигателей. Авторами с использованием методов численной газовой динамики (CFD) проведены вычисления экспериментального ракетного двигателя. Проведенный анализ является основой для проектирования экспериментального образца. Экспериментальное исследование работы нового двигателя проведено с целью подтверждения правильности вычислений. В будущем планируется испытание системы охлаждения двигательной установки, которое будет являться завершением данного проекта

Rab-dependent vesicular traffic affects female gametophyte development in Arabidopsis

Eukaryotic cells rely on the accuracy and efficiency of vesicular traffic. In plants, disturbances in vesicular trafficking are well studied in quickly dividing root meristem cells or polar growing root hairs and pollen tubes. The development of the female gametophyte, a unique haploid reproductive structure located in the ovule, has received far less attention in studies of vesicular transport. Key molecules providing the specificity of vesicle formation and its subsequent recognition and fusion with the acceptor membrane are Rab proteins. Rabs are anchored to membranes by covalently linked geranylgeranyl group(s) that are added by the Rab geranylgeranyl transferase (RGT) enzyme. Here we show that Arabidopsis plants carrying mutations in the gene encoding the beta subunit of RGT (rgtb1) exhibit severely disrupted female gametogenesis and this effect is of sporophytic origin. Mutations in rgtb1 lead to internalization of the PIN1 and PIN3 proteins from the basal membranes to vesicles in pro-vascular cells of the funiculus. Decreased transport of auxin out of the ovule is accompanied by auxin accumulation in a tissue surrounding the growing gametophyte. In addition, female gametophyte development arrests at the uni- or binuclear stage in a significant portion of the rgtb1 ovules. These observations suggest that communication between the sporophyte and the developing female gametophyte relies on Rab dependent vesicular traffic of the PIN1 and PIN3 transporters and auxin efflux out of the ovule.Joanna Rojek, Matthew R Tucker, Sara C Pinto, Michał Rychłowski, Małgorzata Lichocka, Hana Soukupova ... et al