53 research outputs found
Plum pudding random medium model of biological tissue toward remote microscopy from spectroscopic light scattering
Biological tissue has a complex structure and exhibits rich spectroscopic
behavior. There is \emph{no} tissue model up to now able to account for the
observed spectroscopy of tissue light scattering and its anisotropy. Here we
present, \emph{for the first time}, a plum pudding random medium (PPRM) model
for biological tissue which succinctly describes tissue as a superposition of
distinctive scattering structures (plum) embedded inside a fractal continuous
medium of background refractive index fluctuation (pudding). PPRM faithfully
reproduces the wavelength dependence of tissue light scattering and attributes
the "anomalous" trend in the anisotropy to the plum and the powerlaw dependence
of the reduced scattering coefficient to the fractal scattering pudding. Most
importantly, PPRM opens up a novel venue of quantifying the tissue architecture
and microscopic structures on average from macroscopic probing of the bulk with
scattered light alone without tissue excision. We demonstrate this potential by
visualizing the fine microscopic structural alterations in breast tissue
(adipose, glandular, fibrocystic, fibroadenoma, and ductal carcinoma) deduced
from noncontact spectroscopic measurement
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An extreme value theory approach to calculating minimum capital risk requirements
This paper investigates the frequency of extreme events for three LIFFE futures contracts for
the calculation of minimum capital risk requirements (MCRRs). We propose a semiparametric
approach where the tails are modelled by the Generalized Pareto Distribution and
smaller risks are captured by the empirical distribution function. We compare the capital
requirements form this approach with those calculated from the unconditional density and
from a conditional density - a GARCH(1,1) model. Our primary finding is that both in-sample
and for a hold-out sample, our extreme value approach yields superior results than either of
the other two models which do not explicitly model the tails of the return distribution. Since
the use of these internal models will be permitted under the EC-CAD II, they could be widely
adopted in the near future for determining capital adequacies. Hence, close scrutiny of
competing models is required to avoid a potentially costly misallocation capital resources
while at the same time ensuring the safety of the financial system
Evaluation of cell-based and surrogate SARS-CoV-2 neutralization assays
Determinants of protective immunity against SARS-CoV-2 infection require the development of well-standardized, reproducible antibody assays. This need has led to the emergence of a variety of neutralization assays. Head-to-head evaluation of different SARS-CoV-2 neutralization platforms could facilitate comparisons across studies and laboratories. Five neutralization assays were compared using forty plasma samples from convalescent individuals with mild-to-moderate COVID-19: four cell-based systems using either live recombinant SARS-CoV-2 or pseudotyped viral particles created with lentivirus (LV) or vesicular stomatitis virus (VSV) packaging and one surrogate ELISA-based test that measures inhibition of the spike protein receptor binding domain (RBD) binding its receptor, human angiotensin converting enzyme 2 (hACE2). Vero, Vero E6, HEK293T expressing hACE2, and TZM-bl cells expressing hACE2 and transmembrane serine protease 2 were tested. All cell-based assays showed 50% neutralizing dilution (ND50) geometric mean titers (GMTs) that were highly correlated (Pearson r = 0.81â0.89) and ranged within 3.4-fold. The live-virus assay and LV-pseudovirus assays with HEK293T/hACE2 cells showed very similar mean titers: 141 and 178, respectively. ND50 titers positively correlated with plasma IgG targeting SARS-CoV-2 spike and RBD (r = 0.63â0.89), but moderately correlated with nucleoprotein IgG (r = 0.46â0.73). ND80 GMTs mirrored ND50 data and showed similar correlation between assays and with IgG concentrations. The VSV-pseudovirus assay and LV-pseudovirus assay with HEK293T/hACE2 cells in low and high-throughput versions were calibrated against the WHO SARS-CoV-2 IgG standard. High concordance between the outcomes of cell-based assays with live and pseudotyped virions enables valid cross-study comparison using these platforms. 24
Measurement of the total cross section from elastic scattering in pp collisions at sâ = 7 TeV with the ATLAS detector
A measurement of the total pp cross section at the LHC at âs = 7 TeV is presented. In a special run with
high-ÎČ beam optics, an integrated luminosity of 80 ”bâ1 was accumulated in order to measure the differential
elastic cross section as a function of the Mandelstam momentum transfer variable t. The measurement
is performed with the ALFA sub-detector of ATLAS. Using a fit to the differential elastic cross section in
the |t| range from 0.01 GeV2 to 0.1 GeV2 to extrapolate to |t| â 0, the total cross section, Ïtot(pp â X),
is measured via the optical theorem to be:
Ïtot(pp â X) = 95.35 ± 0.38 (stat.) ± 1.25 (exp.) ± 0.37 (extr.) mb,
where the first error is statistical, the second accounts for all experimental systematic uncertainties and the\ud
last is related to uncertainties in the extrapolation to |t| â 0. In addition, the slope of the elastic cross
section at small |t| is determined to be B = 19.73 ± 0.14 (stat.) ± 0.26 (syst.) GeVâ2
Measurement of inclusive jet charged-particle fragmentation functions in Pb plus Pb collisions at root S-NN=2.76 TeV with the ATLAS detector
© 2014 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/license/by/3.0/). Funded by SCOAP3
Standardized Follow-Up Recommendations Improve Reporting of Incidental Renal Lesions in a Community Setting.
Introduction The objective of this quality improvement study was to assess radiology report follow-up recommendation trends upon detection of incidental renal lesions before and after instituting standardized follow-up macros. Materials and methods A retrospective review was performed in 2019 of multiphase imaging workups on renal lesions (n = 396), including the following imaging modalities: ultrasound, CT with and without contrast, and spine MRI. Utilizing the same collection methods, a similar retrospective set of cases was collected in 2021, 12 months following the creation of the renal follow-up macros (n = 501). After exclusions, the second set was left with 98 cases of newly characterized incidental renal lesions. For both sets, we assessed the reports of the exams that initially detected the incidental renal lesion. We evaluated the incident reports for the presence of a follow-up recommendation, recommendation completeness, and alignment with the American College of Radiology (ACR) white paper suggestions for renal lesion follow-up. Results Before the implementation of the standardized renal follow-up macros, initial follow-up recommendations were in concordance with the ACR white paper recommendations in 33 of 98 cases (33.7%), incomplete or discordant in 49 of 98 (50.0%), and absent in 16 of 98 cases (16.3%). Following the institution of our macros, there was an improvement in concordant follow-up recommendations (51/98; 52.0%) (p = 0.009), a decrease in the number of incomplete or discordant recommendations (37/98; 37.8%), and a decrease in the number of reports lacking a follow-up recommendation (10/98; 10.2%). Conclusion Utilization of standard language renal lesion follow-up macros improves the rate of appropriate follow-up recommendations in radiology reports when encountering a previously unknown incidental renal lesion
Energy-linked reactions in mitochondria: Manometric errors in the determination of P/O ratios
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