3,562 research outputs found

    A new A_n extension of Ramanujan's 1-psi-1 summation with applications to multilateral A_n series

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    In this article, we derive some identities for multilateral basic hypergeometric series associated to the root system A_n. First, we apply Ismail's argument to an A_n q-binomial theorem of Milne and derive a new A_n generalization of Ramanujan's 1-psi-1 summation theorem. From this new A_n 1-psi-1 summation and from an A_n 1-psi-1 summation of Gustafson we deduce two lemmas for deriving simple A_n generalizations of bilateral basic hypergeometric series identities. These lemmas are closely related to the Macdonald identities for A_n. As samples for possible applications of these lemmas, we provide several A_n extensions of Bailey's 2-psi-2 transformations, and several A_n extensions of a particular 2-psi-2 summation.Comment: LaTeX2e, 26 pages, submitted to Rocky Mount. J. Math., spec. vol., conference proceedings of SF2000, Tempe, Arizona, May 29 - June 9, 200

    Prostate cancer treatment with Irreversible Electroporation (IRE): Safety, efficacy and clinical experience in 471 treatments.

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    BackgroundIrreversible Electroporation (IRE) is a novel image-guided tissue ablation technology that induces cell death via very short but strong pulsed electric fields. IRE has been shown to have preserving properties towards vessels and nerves and the extracellular matrix. This makes IRE an ideal candidate to treat prostate cancer (PCa) where other treatment modalities frequently unselectively destroy surrounding structures inducing severe side effects like incontinence or impotence. We report the retrospective assessment of 471 IRE treatments in 429 patients of all grades and stages of PCa with 6-year maximum follow-up time.Material and findingsThe patient cohort consisted of low (25), intermediate (88) and high-risk cancers (312). All had multi-parametric magnetic resonance imaging, and 199 men had additional 3D-mapping biopsy for diagnostic work-up prior to IRE. Patients were treated either focally (123), sub-whole-gland (154), whole-gland (134) or for recurrent disease (63) after previous radical prostatectomy, radiation therapy, etc. Adverse effects were mild (19.7%), moderate (3.7%) and severe (1.4%), never life-threatening. Urinary continence was preserved in all cases. IRE-induced erectile dysfunction persisted in 3% of the evaluated cases 12 months post treatment. Mean transient IIEF-5-Score reduction was 33% within 12-month post IRE follow-up and 15% after 12 months. Recurrences within the follow-up period occurred in 10% of the treated men, 23 in or adjacent to the treatment field and 18 outside the treatment field (residuals). Including residuals for worst case analysis, Kaplan Maier estimation on recurrence rate at 5 years resulted in 5.6% (CI95: 1.8-16.93) for Gleason 6, 14.6% (CI95: 8.8-23.7) for Gleason 7 and 39.5% (CI95: 23.5-61.4) for Gleason 8-10.ConclusionThe results indicate comparable efficacy of IRE to standard radical prostatectomy in terms of 5-year recurrence rates and better preservation of urogenital function, proving the safety and suitability of IRE for PCa treatment. The data also shows that IRE, besides focal therapy of early PCa, can also be used for whole-gland ablations, in patients with recurrent PCa, and as a problem-solver for local tumor control in T4-cancers not amenable to surgery and radiation therapy anymore

    Beats of the Magnetocapacitance Oscillations in Lateral Semiconductor Superlattices

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    We present calculations on the magnetocapacitance of the two-dimensional electron gas in a lateral semiconductor superlattice under two-dimensional weak periodic potential modulation in the presence of a perpendicular magnetic field. Adopting a Gaussian broadening of magnetic-field-dependent width in the density of states, we present explicit and simple expressions for the magnetocapacitance, valid for the relevant weak magnetic fields and modulation strengths. As the modulation strength in both directions increase, beats of the magnetocapacitance oscillations are observed, in the low magnetic field range (Weiss-oscillations regime), which are absent in the one-dimensional weak modulation case.Comment: 11 pages, 7 figures, accepted by Mod. Phys. Lett. B (March 2007

    Conditional quantum logic using two atomic qubits

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    In this paper we propose and analyze a feasible scheme where the detection of a single scattered photon from two trapped atoms or ions performs a conditional unitary operation on two qubits. As examples we consider the preparation of all four Bell states, the reverse operation that is a Bell measurement, and a CNOT gate. We study the effect of atomic motion and multiple scattering, by evaluating Bell inequalities violations, and by calculating the CNOT gate fidelity.Comment: 23 pages, 8 figures in 11 file

    Quantum computing with spatially delocalized qubits

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    We analyze the operation of quantum gates for neutral atoms with qubits that are delocalized in space, i.e., the computational basis states are defined by the presence of a neutral atom in the ground state of one out of two trapping potentials. The implementation of single qubit gates as well as a controlled phase gate between two qubits is discussed and explicit calculations are presented for rubidium atoms in optical microtraps. Furthermore, we show how multi-qubit highly entangled states can be created in this scheme.Comment: 4 pages, 4 figure

    Stable Dried Catalase Particles Prepared by Electrospraying

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    Therapeutic proteins and peptides are clinically important, offering potency while reducing the potential for off-target effects. Research interest in developing therapeutic polypeptides has grown significantly during the last four decades. However, despite the growing research effort, maintaining the stability of polypeptides throughout their life cycle remains a challenge. Electrohydrodynamic (EHD) techniques have been widely explored for encapsulation and delivery of many biopharmaceuticals. In this work, we explored monoaxial electrospraying for encapsulation of bovine liver catalase, investigating the effects of the different components of the electrospraying solution on the integrity and bioactivity of the enzyme. The catalase was successfully encapsulated within polymeric particles made of polyvinylpyrrolidone (PVP), dextran, and polysucrose. The polysorbate 20 content within the electrospraying solution (50 mM citrate buffer, pH 5.4) affected the catalase loading-increasing the polysorbate 20 concentration to 500 μg/mL resulted in full protein encapsulation but did not prevent loss in activity. The addition of ethanol (20% v/v) to a fully aqueous solution improves the electrospraying process by reducing surface tension, without loss of catalase activity. The polymer type was shown to have the greatest impact on preserving catalase activity within the electrosprayed particles. When PVP was the carrier there was no loss in activity compared with fresh aqueous solutions of catalase. The optimum particles were obtained from a 20% w/v PVP or 30% w/v PVP-trehalose (1:1 w/w) solution. The addition of trehalose confers stability advantages to the catalase particles. When trehalose-PVP particles were stored at 5 °C, enzymatic activity was maintained over 3 months, whereas for the PVP-only analogue a 50% reduction in activity was seen. This demonstrates that processing catalase by monoaxial electrospraying can, under optimised conditions, result in stable polymeric particles with no loss of activity

    Theta Functions, Elliptic Hypergeometric Series, and Kawanaka's Macdonald Polynomial Conjecture

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    We give a new theta-function identity, a special case of which is utilised to prove Kawanaka's Macdonald polynomial conjecture. The theta-function identity further yields a transformation formula for multivariable elliptic hypergeometric series which appears to be new even in the one-variable, basic case

    Modeling Climate Feedbacks to Energy Demand: The Case of China

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    Abstract in HTML and technical report in PDF available on the Massachusetts Institute of Technology Joint Program on the Science and Policy of Global Change website (http://mit.edu/globalchange/www/).This paper is an empirical investigation of the effects of climate on the use of electricity by consumers and producers in urban and rural areas within China. It takes advantage of an unusual combination of temporal and regional data sets in order to estimate temperature, as well as price and income elasticities of electricity demand. The estimated positive temperature/electric power feedback implies a continually increasing use of energy to produce electric power which, in China, is primarily based on coal. In the absence of countervailing measures, this will contribute to increased emissions, increased atmospheric concentrations of greenhouse gases, and increases in greenhouse warming.This study received funding from the MIT Joint Program on the Science and Policy of Global Change, which is supported by a consortium of government, industry and foundation sponsors
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