150 research outputs found
Catechol[4]arene: The Missing Chiral Member of the Calix[4]arene Family
A missing, inherently chiral member of the calix[4]arene family denoted "catechol[4]arene" was synthesized. Its properties were studied and compared to the ones of its close relatives resorcin[4]arene and pyrogallol[4]arene. This novel supramolecular host exhibits binding capabilities that are superior to its sister molecules in polar media. The enantiomerically pure forms of the macrocycle display modest recognition of chiral ammonium salts
Intraoperative radiotherapy (IORT) is an option for patients with localized breast recurrences after previous external-beam radiotherapy
<p>Abstract</p> <p>Background</p> <p>For patients suffering of recurrent breast cancer within the irradiated breast, generally mastectomy is recommended. The normal tissue tolerance does not permit a second full-dose course of radiotherapy to the entire breast after a second breast-conserving surgery (BCS). A novel option is to treat these patients with partial breast irradiation (PBI). This approach is based on the hypothesis that re-irradiation of a limited volume will be effective and result in an acceptable frequency of side effects. The following report presents a single center experience with intraoperative radiotherapy (IORT) during excision of recurrent breast cancer in the previously irradiated breast.</p> <p>Methods</p> <p>Between 4/02 and 11/06, 15 patients were treated for in-breast recurrences at a median of 10 years (3–25) after previous EBRT (10 recurrences in the initial tumor bed, 3 elsewhere in-breast failures, 2 invasive recurrences after previous DCIS). Additional 2 patients were selected for IORT with new primary breast cancer after previous partial breast EBRT for treatment of Hodgkin's disease. IORT with a single dose of 14.7 – 20 Gy 50 kV X-rays at the applicator surface was delivered with the Intrabeam™-device (Carl Zeiss, Oberkochen, Germany).</p> <p>Results</p> <p>After a median follow-up of 26 months (1–60), no local recurrence occurred. 14 out of 17 patients are alive and free of disease progression. Two patients are alive with distant metastases. One patient died 26 months after BCS/IORT due to pulmonary metastases diagnosed 19 months after BCS/IORT. Acute toxicity after IORT was mild with no Grade 3/4 toxicities and cosmetic outcome showed excellent/good/fair results in 7/7/3 cases.</p> <p>Conclusion</p> <p>IORT for recurrent breast cancer using low energy X-rays is a valuable option for patients with recurrent breast cancer after previous radiotherapy.</p
Correlated Strength in Nuclear Spectral Function
We have carried out an (e,e'p) experiment at high momentum transfer and in
parallel kinematics to measure the strength of the nuclear spectral function
S(k,E) at high nucleon momenta k and large removal energies E. This strength is
related to the presence of short-range and tensor correlations, and was known
hitherto only indirectly and with considerable uncertainty from the lack of
strength in the independent-particle region. This experiment confirms by direct
measurement the correlated strength predicted by theory.Comment: 4 pages, 2 figures, accepted by Phys. Rev. Let
High-fidelity transmission of entanglement over a high-loss freespace channel
Quantum entanglement enables tasks not possible in classical physics. Many
quantum communication protocols require the distribution of entangled states
between distant parties. Here we experimentally demonstrate the successful
transmission of an entangled photon pair over a 144 km free-space link. The
received entangled states have excellent, noise-limited fidelity, even though
they are exposed to extreme attenuation dominated by turbulent atmospheric
effects. The total channel loss of 64 dB corresponds to the estimated
attenuation regime for a two-photon satellite quantum communication scenario.
We confirm that the received two-photon states are still highly entangled by
violating the CHSH inequality by more than 5 standard deviations. From a
fundamental point of view, our results show that the photons are virtually not
subject to decoherence during their 0.5 ms long flight through air, which is
encouraging for future world-wide quantum communication scenarios.Comment: 5 pages, 3 figures, replaced paper with published version, added
journal referenc
Requirement of DNMT1 to orchestrate epigenomic reprogramming for NPM-ALK-driven lymphomagenesis
Cometary dust analogues for physics experiments
The CoPhyLab (Cometary Physics Laboratory) project is designed to study the
physics of comets through a series of earth-based experiments. For these
experiments, a dust analogue was created with physical properties comparable to
those of the non-volatile dust found on comets. This "CoPhyLab dust" is planned
to be mixed with water and CO ice and placed under cometary conditions in
vacuum chambers to study the physical processes taking place on the nuclei of
comets. In order to develop this dust analogue, we mixed two components
representative for the non-volatile materials present in cometary nuclei. We
chose silica dust as representative for the mineral phase and charcoal for the
organic phase, which also acts as a darkening agent. In this paper, we provide
an overview of known cometary analogues before presenting measurements of eight
physical properties of different mixtures of the two materials and a comparison
of these measurements with known cometary values. The physical properties of
interest are: particle size, density, gas permeability, spectrophotometry,
mechanical, thermal and electrical properties. We found that the analogue dust
that matches the highest number of physical properties of cometary materials
consists of a mixture of either 60\%/40\% or 70\%/30\% of silica dust/charcoal
by mass. These best-fit dust analogue will be used in future CoPhyLab
experiments
Free-Space distribution of entanglement and single photons over 144 km
Quantum Entanglement is the essence of quantum physics and inspires
fundamental questions about the principles of nature. Moreover it is also the
basis for emerging technologies of quantum information processing such as
quantum cryptography, quantum teleportation and quantum computation. Bell's
discovery, that correlations measured on entangled quantum systems are at
variance with a local realistic picture led to a flurry of experiments
confirming the quantum predictions. However, it is still experimentally
undecided whether quantum entanglement can survive global distances, as
predicted by quantum theory. Here we report the violation of the
Clauser-Horne-Shimony-Holt (CHSH) inequality measured by two observers
separated by 144 km between the Canary Islands of La Palma and Tenerife via an
optical free-space link using the Optical Ground Station (OGS) of the European
Space Agency (ESA). Furthermore we used the entangled pairs to generate a
quantum cryptographic key under experimental conditions and constraints
characteristic for a Space-to-ground experiment. The distance in our experiment
exceeds all previous free-space experiments by more than one order of magnitude
and exploits the limit for ground-based free-space communication; significantly
longer distances can only be reached using air- or space-based platforms. The
range achieved thereby demonstrates the feasibility of quantum communication in
space, involving satellites or the International Space Station (ISS).Comment: 10 pages including 2 figures and 1 table, Corrected typo
A rapid assessment of the decapod fauna in the Rio Tahuamanu and Rio Manuripi Basins, with new records of shrimps and crabs for Bolivia (Crustacea, Decapoda, Palaemonidae, Sergestidae, Trichodactylidae)
Obtaining Adequate Surgical Margins in Breast-Conserving Therapy for Patients with Early-Stage Breast Cancer: Current Modalities and Future Directions
Inadequate surgical margins represent a high risk for adverse clinical outcome in breast-conserving therapy (BCT) for early-stage breast cancer. The majority of studies report positive resection margins in 20% to 40% of the patients who underwent BCT. This may result in an increased local recurrence (LR) rate or additional surgery and, consequently, adverse affects on cosmesis, psychological distress, and health costs. In the literature, various risk factors are reported to be associated with positive margin status after lumpectomy, which may allow the surgeon to distinguish those patients with a higher a priori risk for re-excision. However, most risk factors are related to tumor biology and patient characteristics, which cannot be modified as such. Therefore, efforts to reduce the number of positive margins should focus on optimizing the surgical procedure itself, because the surgeon lacks real-time intraoperative information on the presence of positive resection margins during breast-conserving surgery. This review presents the status of pre- and intraoperative modalities currently used in BCT. Furthermore, innovative intraoperative approaches, such as positron emission tomography, radioguided occult lesion localization, and near-infrared fluorescence optical imaging, are addressed, which have to prove their potential value in improving surgical outcome and reducing the need for re-excision in BCT
The behaviour of repeat visitors to museums: Review and empirical findings
This study presents a theoretical and operational framework for analysing repeat visit to museums. Starting from the literature on repeat visit in tourism, the specificities of these cultural attractions are made explicit through a review of theoretical and applied works. Consistently with previous contributors, the paper suggests that the analysis of actual past behaviours has to be preferred to the one of attitudes. The application of proper econometric models is also remarked in order to put into account individual profiles. Information coming from three techniques is then used in an integrated way in order to provide a more comprehensive view of the phenomenon. Evidence from an ad hoc survey suggests the necessity to give a greater attention to perceived cultural value during the visit, promoting cultural events during the week and addressed to children, and taking care of those visitors that come from far places also through an integrated tourist supply. © 2013 Springer Science+Business Media Dordrecht
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