5,989 research outputs found
Crohn's disease activity index and Vienna classification - Is it worthwhile to calculate before surgery?
Background: Crohn's disease (CD) patients with increased disease activity may reveal an increased risk for perioperative complications. The `Crohn's disease activity index' (CDAI) and the `Vienna classification' (VC) were developed for standardized disease activity estimations. The significance of these scores to predict extent, type and early outcome of surgery in CD patients was analyzed. Methods: In 179 surgically treated CD patients, the CDAI and VC were assessed from a prospective database. Relations of the scores with CD risk factors, type, number, location and complications of surgery were analyzed. Results: VC behavior and location subtypes were associated with distinct types of surgery (i.e. `strictureplasty' in `stricturing disease', `colon surgery' in `colon involvement'), but not with surgery type and extent or outcome. Surgery extent (i.e. with 5 vs. 3 `surgical sites' 425 +/- 25 vs. 223.3 +/- 25) and complications (357.1 +/- 36.9 (with) vs. 244.4 +/- 13 (without)) were associated with elevated CDAI levels; however, nicotine abuse remained the only significant risk factor for perioperative complications after multiple logistic regression. Conclusion: The significance of VC or CDAI for predicting the extent of surgery or complications is limited. None of the tested variables except preoperative nicotine abuse influenced the likelihood for perioperative complications. Copyright (c) 2006 S. Karger AG, Base
Sarkopenija – skrandžio vėžio chirurgijoje neįvertintas rizikos veiksnys
Surgery remains the only potentially curative option for gastric cancer, although it is related to high postoperative morbidity and mortality rate. Approximately every second gastric cancer patient is diagnosed with sarcopenia, which is a significant risk factor for postoperative complications and poor long-term outcomes. However, sarcopenia is underestimated in routine clinical practice, since it remains the interest of clinical trials. Sarcopenia diagnostic criteria are not fully standardized, but it consists of tests for muscle strength, quantity and quality. They include grip strength, chair stand test, computed tomography, magnetic resonance imaging, ultrasound, bioelectrical impedance analysis and densitometry tests. Regarding the growing evidence for sarcopenia impact on surgical gastric cancer treatment results, it is a high probability that sarcopenia assessment will come to routine clinical practice. Although, until then there is a need for further clinical trials to standardize the diagnostic and to find effective treatment strategies.Chirurgija yra pagrindinis skrandžio vėžio gydymo metodas, leidžiantis tikėtis visiško pasveikimo. Operacijos dėl skrandžio vėžio yra didelės apimties, jos susijusios su didele pooperacinių komplikacijų rizika. Maždaug pusei sergančiųjų skrandžio vėžiu nustatoma sarkopenija. Tai reikšmingas pooperacinių komplikacijų rizikos veiksnys, lemiantis prastesnius atokiuosius gydymo rezultatus.Sarkopenija vis dar yra tik klinikinių tyrimų objektas, šiandienos rutininėje klinikinėje praktikoje ji nevertinama. Sarkopenijos diagnostika apima tyrimus, kuriais siekiama nustatyti raumenų jėgą, masę ir kokybę, tačiau diagnostikos metodika nėra galutinai standartizuota. Diagnostikai taikomi plaštakos griebimo jėgos, „sėsti – stoti“ testo, kompiuterinės tomografijos, magnetinio rezonanso, ultragarso, bioimpedanso ir densitometrijos tyrimai.Sarkopenijos reikšmė skrandžio vėžiui gydyti vis labiau auga. Tikėtina, kad netolimoje ateityje sarkopenijos vertinimas ir gydymas taps kasdienės klinikinės praktikos dalimi. Taigi tikslinga atlikti papildomus klinikinius tyrimus, kurie padėtų standartizuoti diagnostiką ir rasti efektyvius gydymo metodus
Superconducting nanowire photon number resolving detector at telecom wavelength
The optical-to-electrical conversion, which is the basis of optical
detectors, can be linear or nonlinear. When high sensitivities are needed
single-photon detectors (SPDs) are used, which operate in a strongly nonlinear
mode, their response being independent of the photon number. Nevertheless,
photon-number resolving (PNR) detectors are needed, particularly in quantum
optics, where n-photon states are routinely produced. In quantum communication,
the PNR functionality is key to many protocols for establishing, swapping and
measuring entanglement, and can be used to detect photon-number-splitting
attacks. A linear detector with single-photon sensitivity can also be used for
measuring a temporal waveform at extremely low light levels, e.g. in
long-distance optical communications, fluorescence spectroscopy, optical
time-domain reflectometry. We demonstrate here a PNR detector based on parallel
superconducting nanowires and capable of counting up to 4 photons at
telecommunication wavelengths, with ultralow dark count rate and high counting
frequency
Pilot performance of a dedicated prostate PET suitable for diagnosis and biopsy guidance
[EN] Background: Prostate cancer (PCa) represents one of the most common types of
cancers facing the male population. Nowadays, to confirm PCa, systematic or
multiparametric MRI-targeted transrectal or transperineal biopsies of the prostate are
required. However, due to the lack of an accurate imaging technique capable to precisely
locate cancerous cells in the prostate, ultrasound biopsies sample random parts of the
prostate and, therefore, it is possible to miss regions where those cancerous cells are
present. In spite of the improvement with multiparametric MRI, the low reproducibility of
its reading undermines the specificity of the method. Recent development of prostatespecific radiotracers has grown the interest on using positron emission tomography (PET)
scanners for this purpose, but technological improvements are still required (current
scanners have resolutions in the range of 4¿5 mm).
Results: The main goal of this work is to improve state-of-the-art PCa imaging and
diagnosis. We have focused our efforts on the design of a novel prostate-dedicated PET
scanner, named ProsPET. This system has small scanner dimensions defined by a ring of
just 41 cm inner diameter. In this work, we report the design, implementation, and
evaluation (both through simulations and real data) of the ProsPET scanner. We have
been able to achieve < 2 mm resolution in reconstructed images and high sensitivity. In
addition, we have included a comparison with the Philips Gemini-TF scanner, which is
used for routine imaging of PCa patients. The ProsPET exhibits better contrast, especially
for rod sizes as small as 4.5 mm in diameter. Finally, we also show the first reconstructed
image of a PCa patient acquired with the ProsPET.
Conclusions: We have designed and built a prostate specific PET system, with a small
footprint and improved spatial resolution when compared to conventional whole-body
PET scanners. The gamma ray impact within each detector block includes accurate DOI
determination, correcting for the parallax error. The potential role of combined organdedicated prostate-specific membrane antigen (PSMA) PET and ultrasound devices, as a
prebiopsy diagnostic tool, could be used to guide sampling of the most aggressive sites
in the prostate.The work presented in this article has been partially funded by a research grant from the regional government of the Comunitat Valenciana (Spain), co-funded by the European Union ERDF funds (European Regional Development Fund) of the Comunitat Valenciana 2014-2020, with reference IDIFEDER/2018/032 (High-Performance Algorithms for the Modelling, Simulation and early Detection of diseases in Personalized Medicine).
This project has also received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (grant agreement No 695536). It has also been supported by the EU Grant 603002 under the FP7 program and by the Spanish Ministerio de Economia, Industria y Competitividad under Grant e and through PROSPET (DTS15/00152) funded by the Ministerio de Economia y Competitividad.Cañizares-Ledo, G.; Gonzalez-Montoro, A.; Freire, M.; Lamprou, E.; Barrio, J.; Sánchez Martínez, F.; Benlloch Baviera, JM.... (2020). Pilot performance of a dedicated prostate PET suitable for diagnosis and biopsy guidance. EJNMMI Physics. 7(1):1-17. https://doi.org/10.1186/s40658-020-00305-yS11771GLOBOCAN 2018. http://www.gco.iarc.fr/today/ datasources-methods. Accessed 26 Dec 2019.Ferlay J, et al. Cancer incidence and mortality worldwide: sources, methods and major patterns in GLOBOCAN. Int J Cancer. 2012;2015:136–E359.Rawla P. Epidemiology of prostate cancer. 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MR-guided focused ultrasound: enhancement of intratumoral uptake of [H]-docetaxel in vivo. Phys Med Biol. 2010;55(24):–7399.Osborne JR, et al. Prostate-specific membrane antigen-based imaging. Seminars and Original Investigations: Urologic Oncology; 2012.Gonzalez AJ, et al. Organ-dedicated molecular imaging systems. IEEE Trans. Rad. Plasma Med. Scie. 2018;2:388.Majewski S, Proffitt J. Dedicated mobile high resolution prostate PET imager with an insertable transrectal probe. US Patent. 2010;7:858–944.Weinberg IN, et al. Flexible geometries for hand-held PET and SPECT cameras. IEEE NSS-MIC Conference Record. 2002.Weinberg I. Dedicated apparatus and method for positron emission tomography of the prostate. US Patent. 2006;7:102–34.Gonzalez-Montoro A, et al. Performance study of a large monolithic LYSO PET detector with accurate photon DOI using retroreflector layers. IEEE Trans. Rad. Plasma Med. Scie. 2017;1:229.Gonzalez-Montoro A, et al. Detector block performance based on a monolithic LYSO crystal using a novel signal multiplexing method. Nucl Instrum Meth. 2018;912:372-77.Gonzalez-Montoro A, et al. Performance comparison of large-area SiPM arrays suitable for gamma ray detectors. Biomed Phys Eng Express. 2019;5:045013.Seimetz M, et al. Correction algorithms for signal reduction in insensitive areas of a small gamma camera. J Instrum. 2014;9(05):C05042.Freire M, et al. Calibration of gamma ray impacts in monolithic-based detectors using Voronoi diagrams. In IEEE Transactions on Radiation and Plasma Medical Sciences. 2019. https://doi.org/10.1109/TRPMS.2019.2947716 .Jan S, et al. GATE: a simulation toolkit for PET and SPECT. Phys Med Biol. 2004;49:4543–61.Merlin T, et al. CASToR: a generic data organization and processing code framework for multi-modal and multi-dimensional tomographic reconstruction. Phys Med Biol. 2018;63(18):5505.Jacobs F, et al. A fast algorithm to calculate the exact radiological path through a pixel or voxel space. J Comput Inf Technol. 1998;6(1).Gonzalez-Montoro A, et al. Novel method to measure the intrinsic spatial resolution in PET detectors based on monolithic crystals. Nucl. Instrum. Meth. A. 2019;920:39(9).Vicente E, et al. Normalization in 3D PET: dependence on the activity distribution of the source. IEEE Nuclear Science Symposium Conference Record. 2006:M06–379.Soriano A, et al. Attenuation correction without transmission scan for the MAMMI breast PET. Nucl Instrum Meth A. 2011;648:S75.Yushkevich PA, et al. User-guided 3D active contour segmentation of anatomical structures: significantly improved efficiency and reliability. Neuroimage. 2006;34(3):1116-28.Gonzalez AJ, et al. Initial results of the MINDView PET insert inside the 3T mMR. IEEE Trans Rad Plasma Med Scie. 2019;3:343.Suti S, et al. Performance of Philips Gemini TF PET/CT scanner with special consideration for its time-of-flight imaging capabilities. J Nucl Med. 2007;48(3):471–80.Watson C, et al. NEMA NU 2 performance tests for scanners with intrinsic radioactivity. J Nucl Med. 2004;45:822.National Electrical Manufacturers Association. NEMA NU 4-2008. Performance measurements of small animal positron emission tomographs. 2008.Gonzalez AJ, et al. A PET design based on SiPM and monolithic LYSO crystals: performance evaluation. IEEE Trans Nucl Scie. 2016;63:2471.Barbosa FG. Clinical perspectives of PSMA PET/MRI for prostate cancer. Clinics. 2018;73(Suppl 1):e586s.Uprimny C, et al. (68)Ga-PSMA-11 PET/CT in primary staging of prostate cancer: PSA and Gleason score predict the intensity of tracer accumulation in the primary tumour. 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Universality of Phases in QCD and QCD-like Theories
We argue that the whole or the part of the phase diagrams of QCD and QCD-like
theories should be universal in the large-N_c limit through the orbifold
equivalence. The whole phase diagrams, including the chiral phase transitions
and the BEC-BCS crossover regions, are identical between SU(N_c) QCD at finite
isospin chemical potential and SO(2N_c) and Sp(2N_c) gauge theories at finite
baryon chemical potential. Outside the BEC-BCS crossover region in these
theories, the phase diagrams are also identical to that of SU(N_c) QCD at
finite baryon chemical potential. We give examples of the universality in some
solvable cases: (i) QCD and QCD-like theories at asymptotically high density
where the controlled weak-coupling calculations are possible, (ii) chiral
random matrix theories of different universality classes, which are solvable
large-N (large volume) matrix models of QCD. Our results strongly suggest that
the chiral phase transition and the QCD critical point at finite baryon
chemical potential can be studied using sign-free theories, such as QCD at
finite isospin chemical potential, in lattice simulations.Comment: v1: 35 pages, 6 figures; v2: 37 pages, 6 figures, minor improvements,
conclusion unchanged; v3: version published in JHE
Quantum Holographic Encoding in a Two-dimensional Electron Gas
The advent of bottom-up atomic manipulation heralded a new horizon for
attainable information density, as it allowed a bit of information to be
represented by a single atom. The discrete spacing between atoms in condensed
matter has thus set a rigid limit on the maximum possible information density.
While modern technologies are still far from this scale, all theoretical
downscaling of devices terminates at this spatial limit. Here, however, we
break this barrier with electronic quantum encoding scaled to subatomic
densities. We use atomic manipulation to first construct open
nanostructures--"molecular holograms"--which in turn concentrate information
into a medium free of lattice constraints: the quantum states of a
two-dimensional degenerate Fermi gas of electrons. The information embedded in
the holograms is transcoded at even smaller length scales into an atomically
uniform area of a copper surface, where it is densely projected into both two
spatial degrees of freedom and a third holographic dimension mapped to energy.
In analogy to optical volume holography, this requires precise amplitude and
phase engineering of electron wavefunctions to assemble pages of information
volumetrically. This data is read out by mapping the energy-resolved electron
density of states with a scanning tunnelling microscope. As the projection and
readout are both extremely near-field, and because we use native quantum states
rather than an external beam, we are not limited by lensing or collimation and
can create electronically projected objects with features as small as ~0.3 nm.
These techniques reach unprecedented densities exceeding 20 bits/nm2 and place
tens of bits into a single fermionic state.Comment: Published online 25 January 2009 in Nature Nanotechnology; 12 page
manuscript (including 4 figures) + 2 page supplement (including 1 figure);
supplementary movie available at http://mota.stanford.ed
Calcium Channel Blockers, More than Diuretics, Enhance Vascular Protective Effects of Angiotensin Receptor Blockers in Salt-Loaded Hypertensive Rats
The combination therapy of an angiotensin receptor blocker (ARB) with a calcium channel blocker (CCB) or with a diuretic is favorably recommended for the treatment of hypertension. However, the difference between these two combination therapies is unclear. The present work was undertaken to examine the possible difference between the two combination therapies in vascular protection. Salt-loaded stroke-prone spontaneously hypertensive rats (SHRSP) were divided into 6 groups, and they were orally administered (1) vehicle, (2) olmesartan, an ARB, (3) azelnidipine, a CCB, (4) hydrochlorothiazide, a diuretic, (5) olmesartan combined with azelnidipine, or (6) olmesartan combined with hydrochlorothiazide. Olmesartan combined with either azelnidipine or hydrochlorothiazide ameliorated vascular endothelial dysfunction and remodeling in SHRSP more than did monotherapy with either agent. However, despite a comparable blood pressure lowering effect between the two treatments, azelnidipine enhanced the amelioration of vascular endothelial dysfunction and remodeling by olmesartan to a greater extent than did hydrochlorothiazide in salt-loaded SHRSP. The increased enhancement by azelnidipine of olmesartan-induced vascular protection than by hydrochlorothiazide was associated with a greater amelioration of vascular nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, superoxide, mitogen-activated protein kinase activation, and with a greater activation of the Akt/endothelial nitric oxide synthase (eNOS) pathway. These results provided the first evidence that a CCB potentiates the vascular protective effects of an ARB in salt-sensitive hypertension, compared with a diuretic, and provided a novel rationale explaining the benefit of the combination therapy with an ARB and a CCB
Circuit Quantum Electrodynamics: Coherent Coupling of a Single Photon to a Cooper Pair Box
Under appropriate conditions, superconducting electronic circuits behave
quantum mechanically, with properties that can be designed and controlled at
will. We have realized an experiment in which a superconducting two-level
system, playing the role of an artificial atom, is strongly coupled to a single
photon stored in an on-chip cavity. We show that the atom-photon coupling in
this circuit can be made strong enough for coherent effects to dominate over
dissipation, even in a solid state environment. This new regime of matter light
interaction in a circuit can be exploited for quantum information processing
and quantum communication. It may also lead to new approaches for single photon
generation and detection.Comment: 8 pages, 4 figures, accepted for publication in Nature, embargo does
apply, version with high resolution figures available at:
http://www.eng.yale.edu/rslab/Andreas/content/science/PubsPapers.htm
A systematic review of biomarkers for disease progression in Parkinson's disease
Peer reviewedPublisher PD
Selective expansion of viral variants following experimental transmission of a reconstituted feline immunodeficiency virus quasispecies
Following long-term infection with virus derived from the pathogenic GL8 molecular clone of feline immunodeficiency virus (FIV), a range of viral variants emerged with distinct modes of interaction with the viral receptors CD134 and CXCR4, and sensitivities to neutralizing antibodies. In order to assess whether this viral diversity would be maintained following subsequent transmission, a synthetic quasispecies was reconstituted comprising molecular clones bearing envs from six viral variants and its replicative capacity compared in vivo with a clonal preparation of the parent virus. Infection with either clonal (Group 1) or diverse (Group 2) challenge viruses, resulted in a reduction in CD4+ lymphocytes and an increase in CD8+ lymphocytes. Proviral loads were similar in both study groups, peaking by 10 weeks post-infection, a higher plateau (set-point) being achieved and maintained in study Group 1. Marked differences in the ability of individual viral variants to replicate were noted in Group 2; those most similar to GL8 achieved higher viral loads while variants such as the chimaeras bearing the B14 and B28 Envs grew less well. The defective replication of these variants was not due to suppression by the humoral immune response as virus neutralising antibodies were not elicited within the study period. Similarly, although potent cellular immune responses were detected against determinants in Env, no qualitative differences were revealed between animals infected with either the clonal or the diverse inocula. However, in vitro studies indicated that the reduced replicative capacity of variants B14 and B28 in vivo was associated with altered interactions between the viruses and the viral receptor and co-receptor. The data suggest that viral variants with GL8-like characteristics have an early, replicative advantage and should provide the focus for future vaccine development
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