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

Paramecium tredecaurelia: A Unique Non-Polymorphic Species of the P. aurelia spp. Complex (Oligohymenophorea, Ciliophora)

New stands of Paramecium tredecaurelia, a rare species of the P. aurelia spp. complex, were identified in Thailand and Madagascar on the basis of mating reactions and molecular markers (rDNA and mtDNA). Analysis of DNA fragments showed that all P. tredecaurelia strains, the recently recorded ones and the ones known previously from France, Mexico, and Israel, form a monophyletic and well-defined clade in the P. aurelia species trees. All of these strains, collected from different localities around the world, represent identical or nearly identical haplotypes in terms of all the studied DNA fragments. Given the huge distances between particular collection sites, such a low level of variability of the studied sequences may result from a slow rate of evolution in P. tredecaurelia

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

Efficient spatially-resolved multimode quantum memory

We propose a method that enables efficient storage and retrieval of a photonic excitation stored in an ensemble quantum memory consisting of Lambda-type absorbers with non-zero Stokes shift. We show that this can be used to implement a multimode quantum memory storing multiple frequency-encoded qubits in a single ensemble, and allowing their selective retrieval. The read-out scheme applies to memory setups based on both electromagnetically-induced transparency and stimulated Raman scattering, and spatially separates the output signal field from the control fields

Creating diamond color centers for quantum optical applications

Nitrogen vacancy (NV) centers in diamond have distinct promise as solid-state qubits. This is because of their large dipole moment, convenient level structure and very long room-temperature coherence times. In general, a combination of ion irradiation and subsequent annealing is used to create the centers, however for the rigorous demands of quantum computing all processes need to be optimized, and decoherence due to the residual damage caused by the implantation process itself must be mitigated. To that end we have studied photoluminescence (PL) from NV$^-$, NV$^0$ and GR1 centers formed by ion implantation of 2MeV He ions over a wide range of fluences. The sample was annealed at $600^{\circ}$C to minimize residual vacancy diffusion, allowing for the concurrent analysis of PL from NV centers and irradiation induced vacancies (GR1). We find non-monotic PL intensities with increasing ion fluence, monotonic increasing PL in NV$^0$/NV$^-$ and GR1/(NV$^0$ + NV$^1$) ratios, and increasing inhomogeneous broadening of the zero-phonon lines with increasing ion fluence. All these results shed important light on the optimal formation conditions for NV qubits. We apply our findings to an off-resonant photonic quantum memory scheme using vibronic sidebands

Increased expression of leptin and the leptin receptor as a marker of breast cancer progression: possible role of obesity-related stimuli

PURPOSE: Recent in vitro studies suggested that the autocrine leptin loop might contribute to breast cancer development by enhancing cell growth and survival. To evaluate whether the leptin system could become a target in breast cancer therapy, we examined the expression of leptin and its receptor (ObR) in primary and metastatic breast cancer and noncancer mammary epithelium. We also studied whether the expression of leptin/ObR in breast cancer can be induced by obesity-related stimuli, such as elevated levels of insulin, insulin-like growth factor-I (IGF-I), estradiol, or hypoxic conditions. EXPERIMENTAL DESIGN: The expression of leptin and ObR was examined by immunohistochemistry in 148 primary breast cancers and 66 breast cancer metastases as well as in 90 benign mammary lesions. The effects of insulin, IGF-I, estradiol, and hypoxia on leptin and ObR mRNA expression were assessed by reverse transcription-PCR in MCF-7 and MDA-MB-231 breast cancer cell lines. RESULTS: Leptin and ObR were significantly overexpressed in primary and metastatic breast cancer relative to noncancer tissues. In primary tumors, leptin positively correlated with ObR, and both biomarkers were most abundant in G3 tumors. The expression of leptin mRNA was enhanced by insulin and hypoxia in MCF-7 and MDA-MB-231 cells, whereas IGF-I and estradiol stimulated leptin mRNA only in MCF-7 cells. ObR mRNA was induced by insulin, IGF-I, and estradiol in MCF-7 cells and by insulin and hypoxia in MDA-MB-231 cells. CONCLUSIONS: Leptin and ObR are overexpressed in breast cancer, possibly due to hypoxia and/or overexposure of cells to insulin, IGF-I, and/or estradiol

The estrogen receptor alpha:insulin receptor substrate 1 complex in breast cancer: structure-function relationships

Background: Insulin receptor substrate 1 (IRS-1) is a signaling molecule that exerts a key role in mediating cross talk between estrogen receptor a (ERa) and insulin-like growth factor 1 (IGF-1) in breast cancer cells. Previously, we demonstrated that a fraction of IRS-1 binds ERa, translocates to the nucleus, and modulates ERa-dependent transcription at estrogen response elements (ERE). Here, we studied structure–function relationships of the ERa:IRS-1 complex under IGF-1 and/or estradiol (E2) stimulation. Materials and methods: ERa and IRS-1 deletion mutants were used to analyze structural and functional ERa/IRS-1 interactions. IRS-1 binding to ERE and IRS-1 role in ERa-dependent ERE transcription was examined by chromatin immunoprecipitation and gene reporter analysis, respectively. The requirement for IRS-1 in ERa function was tested with RNAi technology. Results: Nuclear translocation of IRS-1 was induced by E2, IGF-1, and a combination of both stimuli. ERa/IRS-1 binding was direct and involved the activation function-1 (AF-1)/DNA binding domain (DBD) region of ERa and two discrete regions of IRS-1 (the N-terminal pleckstrin homology domain and a region within the C-terminus). IRS-1 knock down abrogated IGF-1-dependent transcriptional activity of unliganded ERa, but induced the activity of liganded ERa. Conclusions: ERa/IRS-1 interactions are direct and involve the ERa AF-1/DBD domain and IRS-1 domains mapping within N- and C-terminus. IRS-1 may act as a repressor of liganded ERa and coactivator of unliganded ERa

Obesity hormone leptin: a new target in breast cancer?

Leptin is a multifunctional hormone produced mainly by the adipose tissue and involved in the regulation of food intake and energy balance. In addition, leptin can stimulate mitogenic and angiogenic processes in peripheral organs. Because leptin levels are elevated in obese individuals and excess body weight has been shown to increase breast cancer risk in postmenopausal women, attempts have been made to evaluate whether leptin can promote breast cancer. Data obtained in cell and animal models and analyses of human breast cancer biopsies indeed suggest such an involvement. Furthermore, a recent report clearly shows that targeting leptin signaling may reduce mammary carcinogenesis. Thus, leptin should become a new attractive target in breast cancer

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

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