63,301 research outputs found
Preliminary studies identifying and quantifying trace metal impurities in illicit ecstasy tablets using atomic spectrometry techniques
This paper illustrates some preliminary investigations into using ICP-MS in combination with ET-AAS in the analysis of Ecstasy tablets. Results indicate that a combination of both techniques can show discriminating power between seizures. Descriptions of the modifications made to optimise the ET-AAS system are described
Using problem frames with distributed architectures: a case for cardinality on interfaces
Certain classes of problems amenable to description
using Problem Frames, in particular ones intended to be
implemented using a distributed architecture, can benefit
by the addition of a cardinality specification on the
domain interfaces. This paper presents an example of
such a problem, demonstrates the need for relationship
cardinality, and proposes a notation to represent
cardinality on domain interfaces
Gauge Theory of Composite Fermions: Particle-Flux Separation in Quantum Hall Systems
Fractionalization phenomenon of electrons in quantum Hall states is studied
in terms of U(1) gauge theory. We focus on the Chern-Simons(CS) fermion
description of the quantum Hall effect(QHE) at the filling factor
, and show that the successful composite-fermions(CF) theory
of Jain acquires a solid theoretical basis, which we call particle-flux
separation(PFS). PFS can be studied efficiently by a gauge theory and
characterized as a deconfinement phenomenon in the corresponding gauge
dynamics. The PFS takes place at low temperatures, , where
each electron or CS fermion splinters off into two quasiparticles, a fermionic
chargeon and a bosonic fluxon. The chargeon is nothing but Jain's CF, and the
fluxon carries units of CS fluxes. At sufficiently low temperatures , fluxons Bose-condense uniformly and (partly)
cancel the external magnetic field, producing the correlation holes. This
partial cancellation validates the mean-field theory in Jain's CF approach.
FQHE takes place at as a joint effect of (i) integer QHE of
chargeons under the residual field and (ii) Bose condensation of
fluxons. We calculate the phase-transition temperature and the CF
mass. PFS is a counterpart of the charge-spin separation in the t-J model of
high- cuprates in which each electron dissociates into holon and
spinon. Quasiexcitations and resistivity in the PFS state are also studied. The
resistivity is just the sum of contributions of chargeons and fluxons, and
changes its behavior at , reflecting the change of
quasiparticles from chargeons and fluxons at to electrons at
.Comment: 18 pages, 7 figure
Glucose-6-phosphate-dehydrogenase deficiency as a risk factor in proliferative disorder development
Glucose-6-phosphate dehydrogenase (G6PD) is an important site of metabolic control in the pentose phosphate pathway (PPP) which provides reducing power (NADPH) and pentose phosphates. The former is mainly involved in the detoxification of chemical reactive species; the latter in the regulation of cell proliferation. G6PD deficiency is the most common enzymopathy in the human population, characterized by decreased G6PD activity, mainly in red blood cells, but actually also in nucleated cells. This decreased activity is not due to enzyme synthesis impairment, but rather to reduced enzyme stability, which leads to a shortening of its half-life. Therefore, a major problem is to understand the underlying mechanisms linking G6PD deficiency to oxidative stress and cell proliferation. In order to address this issue, in the present study we utilized, as an experimental model, fibroblasts isolated from pterygium, an ocular proliferative lesion, from G6PD normal and deficient (PFs+ and PFs-, respectively) patients. Our choice was determined by the fact that pterygium is believed to be caused by chronic oxidative stress induced by UV exposure, and that pterygium fibroblasts resemble a tumorigenic phenotype. As controls we utilized fibroblasts isolated from conjunctiva from G6PD normal and deficient patients (NCFs+ and NCFs-, respectively) who had undergone cataract surgery. 
Growth rate analysis revealed that PFs grow faster than NCFs, but while NCFs- grow more slowly than NCFs+, PFs- and PFs+ grow at the same rate. This was associated with significantly lower G6PD activity in NCFs+ compared to NCFs-, while no significant differences in the G6PD activity of PFs+ and PFs- were noted. This result was supported by the finding that in PFs-, G6PD mRNA levels were significantly higher than in PFs+. Another interesting finding of this study was increased green autofluorescence in both NCFs- and PFs- compared to corresponding positive cells, indicative of pronounced oxidative stress in deficient cells. Finally, abnormal accumulation of neutral lipids, mainly cholesterol esters was observed both in PFs- and PFs+ compared to NCFs- and NCFs+. Though further studies are necessary for better understanding the exact mechanism which links G6PD to oxidative stress and cell proliferation, our data allow to speculate on the role of G6PD on tumorigenesis, and to consider G6PD-deficient subjects at major risk to develop common and dreaded proliferative disorders, such as atherosclerosis and cancer. 

CT-based tumour response criteria compared after combined treatment for liver metastases of colorectal cancer
open6noPurpose: The aim of this analysis is to compare different tumour response
criteria (TRC) after chemotherapy combined with bevacizumab in liver
metastases from colorectal cancer (mCRC) to ascertain the best early
prognostic indicator of response.
Methods and Materials: 103 target liver metastases from 65 mCRC patients
treated with chemoterapy plus bevacizumab were examined at the Istituto
Oncologico Veneto IOV-IRCSS (March 2008-January 2013). All patients had
baseline CT and at least one follow-up scan. Tumour response was
retrospectively analyzed by two radiologists using RECIST1.1, modified Choi,
and Chun morphologic criteria. Tumour response, classified as good (complete
or partial response) or poor (stable or progressive disease), was compared
with progression-free survival (PFS) at first follow-up (t1) and time of best
response. Interobserver agreement and concordance between TRC were
measured.
Results: At t1, 32.31% showed a good response according to RECIST1.1
(median PFS 11.1), 84.62% according to Choi (median PFS 10.8). These
percentages rose to 49.23% (median PFS 12.1) and 87.69% (median PFS
10.8), respectively, at the time of best response. According to Chun, 67.69%
showed a good response at the time of best response (median PFS 10.8). The
Choi criteria detected a higher proportion of good responders at t1, showing a
better correlation with PFS; all methods correlated with PFS at the time of best
response.
Conclusion: The Choi criteria proved more consistent in the early detection of
response in mCRC treated with chemotherapy plus bevacizumab,
underscoring the importance of using these criteria in the early assessment of
response to combined treatment.openopenVarotto, A.; Di Grazia, L.; Aliberti, C.; Bergamo, F.; Nardin, M.; Pomerri, F.Varotto, A.; Di Grazia, L.; Aliberti, C.; Bergamo, F.; Nardin, M.; Pomerri, Fabi
Toward a numerical deshaker for PFS
The Planetary Fourier Spectrometer (PFS) onboard Mars Express (MEx) is the
instrument with the highest spectral resolution observing Mars from orbit since
January 2004. It permits studying the atmospheric structure, major and minor
compounds. The present time version of the calibration is limited by the
effects of mechanical vibration, currently not corrected. We proposed here a
new approach to correct for the vibrations based on semi-blind deconvolution of
the measurements. This new approach shows that a correction can be done
efficiently with 85% reduction of the artefacts, in a equivalent manner to the
stacking of 10 spectra. Our strategy is not fully automatic due to the
dependence on some regularisation parameters. It may be applied on the complete
PFS dataset, correcting the large-scale perturbation due to microvibrations for
each spectrum independently. This approach is validated on actual PFS data of
Short Wavelength Channel (SWC), perturbed by microvibrations. A coherence check
can be performed and also validate our approach. Unfortunately, the coherence
check can be done only on the first 310 orbits of MEx only, until the laser
line has been switch off. More generally, this work may apply to numerically
"deshake" Fourier Transform Spectrometer (FTS), widely used in space
experiments or in the laboratory.Comment: 18 pages, 8 figures, submitted to Planetary and Space Scienc
Use of the metastatic breast cancer progression (MBC-P) questionnaire to assess the value of progression-free survival for women with metastatic breast cancer.
While overall survival (OS) has historically been the primary endpoint for clinical trials in oncology, progression-free survival (PFS) has gained acceptance as a valuable surrogate endpoint. However, there are no known published reports about the value of PFS from the patient's perspective. We developed a questionnaire that included items regarding quality of life (QoL) and the importance of different treatment outcomes and presented hypothetical scenarios for which respondents were asked to indicate their preferences concerning treatments as they relate to PFS. 282 women with metastatic breast cancer (MBC), ranging in age from 21 to 80 years completed an online version of this questionnaire. The majority of women (66 %) had been diagnosed with MBC within the previous 3 years and 56 % had been told their MBC had progressed. When asked to rank five treatment characteristics from most important to least important, respondents ranked "extending PFS" as the second most important treatment outcome after OS. When presented with a hypothetical scenario of two women receiving different treatments, respondents preferred the treatment that resulted in longer PFS (16 vs. 12 months), even when OS and side effects were assumed to be equal. Specifically, when asked to consider which woman within the hypothetical scenario had better QoL, physical functioning, and emotional well-being, respondents more often chose the woman who experienced longer PFS (QoL: 40 vs. 6 %; physical functioning: 32 vs. 8 %; emotional well-being: 58 vs. 6 %) compared to the woman within the hypothetical scenario who had a shorter time of progression. Respondents rated their own QoL highest after being told their MBC was responding to treatment (mean score 76.6) versus after the initial diagnosis of breast cancer and MBC (68.5 and 60.3). These findings suggest that extending PFS is an important treatment outcome and, from a patient perspective, improves overall QoL, physical functioning, and emotional well-being
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