348 research outputs found
Noise thermometry applied to thermoelectric measurements in InAs nanowires
We apply noise thermometry to characterize charge and thermoelectric
transport in single InAs nanowires (NWs) at a bath temperature of 4.2 K. Shot
noise measurements identify elastic diffusive transport in our NWs with
negligible electron-phonon interaction. This enables us to set up a measurement
of the diffusion thermopower. Unlike in previous approaches, we make use of a
primary electronic noise thermometry to calibrate a thermal bias across the NW.
In particular, this enables us to apply a contact heating scheme, which is much
more efficient in creating the thermal bias as compared to conventional
substrate heating. The measured thermoelectric Seebeck coefficient exhibits
strong mesoscopic fluctuations in dependence on the back-gate voltage that is
used to tune the NW carrier density. We analyze the transport and
thermoelectric data in terms of approximate Mott's thermopower relation and to
evaluate a gate-voltage to Fermi energy conversion factor
Local noise in a diffusive conductor
The control and measurement of local non-equilibrium configurations is of
utmost importance in applications on energy harvesting, thermoelectrics and
heat management in nano-electronics. This challenging task can be achieved with
the help of various local probes, prominent examples including superconducting
or quantum dot based tunnel junctions, classical and quantum resistors, and
Raman thermography. Beyond time-averaged properties, valuable information can
also be gained from spontaneous fluctuations of current (noise). From these
perspective, however, a fundamental constraint is set by current conservation,
which makes noise a characteristic of the whole conductor, rather than some
part of it. Here we demonstrate how to remove this obstacle and pick up a local
noise temperature of a current biased diffusive conductor with the help of a
miniature noise probe. This approach is virtually noninvasive and extends
primary local measurements towards strongly non-equilibrium regimes.Comment: minor revision, accepted in Scientific Report
The DICE calibration project: design, characterization, and first results
We describe the design, operation, and first results of a photometric
calibration project, called DICE (Direct Illumination Calibration Experiment),
aiming at achieving precise instrumental calibration of optical telescopes. The
heart of DICE is an illumination device composed of 24 narrow-spectrum,
high-intensity, light-emitting diodes (LED) chosen to cover the
ultraviolet-to-near-infrared spectral range. It implements a point-like source
placed at a finite distance from the telescope entrance pupil, yielding a flat
field illumination that covers the entire field of view of the imager. The
purpose of this system is to perform a lightweight routine monitoring of the
imager passbands with a precision better than 5 per-mil on the relative
passband normalisations and about 3{\AA} on the filter cutoff positions. The
light source is calibrated on a spectrophotometric bench. As our fundamental
metrology standard, we use a photodiode calibrated at NIST. The radiant
intensity of each beam is mapped, and spectra are measured for each LED. All
measurements are conducted at temperatures ranging from 0{\deg}C to 25{\deg}C
in order to study the temperature dependence of the system. The photometric and
spectroscopic measurements are combined into a model that predicts the spectral
intensity of the source as a function of temperature. We find that the
calibration beams are stable at the level -- after taking the slight
temperature dependence of the LED emission properties into account. We show
that the spectral intensity of the source can be characterised with a precision
of 3{\AA} in wavelength. In flux, we reach an accuracy of about 0.2-0.5%
depending on how we understand the off-diagonal terms of the error budget
affecting the calibration of the NIST photodiode. With a routine 60-mn
calibration program, the apparatus is able to constrain the passbands at the
targeted precision levels.Comment: 25 pages, 27 figures, accepted for publication in A&
Angiogenesis modifications related with cetuximab plus irinotecan as anticancer treatment in advanced colorectal cancer patients.
Introduction: Angiogenesis has been correlated with increased invasion and metastases in a variety of human
neoplasms. Inadequate inhibition of the growth of tumor microvessels by anticancer agents may result in treatment
failure, rated clinically as progressive or stable disease. We designed this trial to investigate the modification of the
vascular endothelial growth factor (VEGF) and interferon-c (IFN-c) in advanced colorectal cancer patients during
treatment with a weekly combination of cetuximab plus irinotecan.
Materials and methods: Forty-five metastatic colorectal cancer patients were prospectively evaluated for
circulating levels of VEGF and IFN-c during the treatment with cetuximab (initial dose of 400 mg/m2
, followed by
weekly infusions of 250 mg/m2
) plus weekly irinotecan (90 mg/m2
). The circulating levels of the cytokines were
assessed at the following time points: just before and at 1, 21, 50 and 92 days after the start of cetuximab plus
irinotecan treatment.
Results: Basal serum VEGF median levels were significantly decreased just at the first day (after the first treatment
infusion (P = 0.016). The VEGF persisted at the following time points reaching the highest statistical significance
92 days after the first infusion (P < 0.0001). On the contrary, IFN-c values showed a statistical significant increase one
day after the first infusion (P < 0.0001). This effect persisted 21 days after the treatment start (P = 0.001), but was no
more evident at the following time points. Moreover, a linear regression model with variance analysis showed
a significant negative correlation between VEGF and IFN-c values 1, 21 and 50 days after the treatment beginning
(P = 0.002, 0.001 and 0.047, respectively).
Conclusions: This study suggests that a cetuximab may induce a modulation of VEGF circulating levels.
The reduction of VEGF serum levels is a sudden and long lasting phenomenon. Moreover, in our study we
identified a IFN-c increase, even if the specific role of this behavior remains to be investigated
Early magnesium reduction in advanced colorectal cancer patients treated with cetuximab plus irinotecan as predictive factor of efficacy and outcome
Introduction: Magnesium plays a role in a large number of cellular metabolic reactions.
Cetuximab is able to induce hypomagnesemia by interfering with magnesium (Mg2+) transport
in the kidney.We designed this trial to investigate if Mg2+ serum level modifications may be related
with clinical response andoutcome in advancedcolorectal cancer patients during treatment with
cetuximab plus irinotecan.
Experimental Design: Sixty-eight heavily pretreatedmetastatic colorectal cancer patients were
evaluatedfor Mg2+ serum levels at the following time points: before; 6 hours; and1, 7, 14, 21, 50,
and92 days after the start of treatment.
Results: Basal Mg2+ median levels were significantly decreased just 7 days after the first
anticancer infusion and progressively decreased from the 7th day onward, reaching the highest
significance at the last time point (P < 0.0001).Twenty-five patients showeda reduction in median
Mg2+ circulating levels of at least 20% within the 3rdweek after the first infusion. Patients with
this reduction showed a response rate of 64.0% versus 25.6% in the nonreduced Mg2+ group.
The median time to progression was 6.0 versus 3.6 months in the reduced Mg2+ group andin that
without reduction, respectively (P < 0.0001). Overall survival was longer in patients with Mg2+
reduction than in those without (10.7 versus 8.9 months).
Conclusions: Our results confirm that cetuximab treatment may induce a reduction of Mg2+
circulating levels andoffer the first evidence that Mg2+ reduction may represent a new predictive
factor of efficacy in advanced colorectal cancer patients treated with cetuximab plus irinoteca
Single Plasma Concentrations of 1âČâHydroxymidazolam or the Ratio of 1âČâHydroxymidazolam: Midazolam Do Not Predict Midazolam Clearance in Healthy Subjects
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97152/1/009127002237986.pd
Limited Sampling Strategy to Predict AUC of the CYP3A Phenotyping Probe Midazolam in Adults: Application to Various Assay Techniques
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97211/1/00912700222011418.pd
Telomere length is an independent predictor of survival, treatment requirement and Richter's syndrome transformation in chronic lymphocytic leukemia
Telomere length (TL) has been associated with outcome in chronic lymphocytic leukemia (CLL). This extensive analysis assess TL on 401 CLL patients subdivided in one cohorts of patients used as learning (191 patients) and one as blinded validation series (210 patients). A TL cutoff of 5000 bp was chosen by receiver operating characteristic (ROC) analysis and Youden\u2019s index in the learning series. In this series,TLp5000 bp was independently associated to a worse outcome for both overall survival (OS; 105.5 vs 281 months, Po0.001) and treatment-free survival (TFS; 24.6 vs 73 months, Po0.001).In the blinded validation series, TLp5000 bp was confirmed as an independent outcome predictor for OS (79.8 vs not reached, Po0.001) and TFS (15.2 vs 130.8 months, Po0.001). Moreover, TLp5000 bp independently predicted the risk of Richter\u2019s syndrome (5-year risk: 18.9 vs 6.4%, P\ubc0.016). Within CLL subsets defined by biological predictors, TL consistently identified patient subgroups harboring unfavorable prognosis. These results demonstrate that TL is a powerful independent predictor of multiple outcomes in CLL, and contributes to refine the prognostic assessment of this disease when utilized in combination with other prognostic markers. We thus believe that this prognostic biomarker has the potential for a more widespread use in CLL.Telomere length (TL) has been associated with outcome in chronic lymphocytic leukemia (CLL). The aim of this extensive analysis carried out on 401 CLL patients was to assess TL conclusively as a prognostic biomarker. Our study included two cohorts used as learning (191 patients) and blinded validation series (210 patients). A TL cutoff of 5000 bp was chosen by receiver operating characteristic (ROC) analysis and Youden's index in the learning series. In this series, TL< or =5000 bp was independently associated to a worse outcome for both overall survival (OS; 105.5 vs 281 months, P<0.001) and treatment-free survival (TFS; 24.6 vs 73 months, P<0.001). In the blinded validation series, TL< or =5000 bp was confirmed as an independent outcome predictor for OS (79.8 vs not reached, P<0.001) and TFS (15.2 vs 130.8 months, P<0.001). Moreover, TL< or =5000 bp independently predicted the risk of Richter's syndrome (5-year risk: 18.9 vs 6.4%, P=0.016). Within CLL subsets defined by biological predictors, TL consistently identified patient subgroups harboring unfavorable prognosis. These results demonstrate that TL is a powerful independent predictor of multiple outcomes in CLL, and contributes to refine the prognostic assessment of this disease when utilized in combination with other prognostic markers. We thus believe that this prognostic biomarker has the potential for a more widespread use in CLL
Discovering Argumentative Patterns in Energy Polylogues: A Macroscope for Argument Mining
A macroscope is proposed and tested here for the discovery of the unique argumentative footprint that characterizes how a collective (e.g., group, online community) manages differences and pursues disagreement through argument in a polylogue. The macroscope addresses broader analytic problems posed by various conceptualizations of large-scale argument, such as fields, spheres, communities, and institutions. The design incorporates a two-tier methodology for detecting argument patterns of the arguments performed in arguing by an interactive collective that produces views, or topographies, of the ways that issues are generated in the making and defending of standpoints. The design premises for the macroscope build on insights about argument patterns from pragma-dialectical theory by incorporating research and theory on disagreement management and the Argumentum Model of Topics. The design reconceptualizes prototypical and stereotypical argument patterns for characterizing large-scale argumentation. A prototype of the macroscope is tested on data drawn from six threads about oil-drilling and fracking from the subreddit Changemyview. The implementation suggests the efficacy of the macroscopeâs design and potential for identifying what communities make controversial and how the disagreement space in a polylogue is managed through stereotypical argument patterns in terms of claims/premises, inferential relations, and presentational devices
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