459 research outputs found
Development of an electrochemical caffeine sensor for PAT application in the food and beverage industry
This work reports on the development of an electrochemical sensor for on-line caffeine detection using screen printed graphite electrodes. The effects of solution pH and pre-treatment procedures on electrode performance have been discussed, as well as the modification of the electrode surface for increased electrode sensitivity. Successful caffeine determination in soft drink samples is described. The results indicate the potential of electrochemical sensors to compare and compete with the current off-line methods of caffeine analysis, such as HPLC, allowing for both a reduction in time and cost of product quality analysis. The successful performance of the screen printed electrode, as well as its low cost and small dimensions, will allow for efficient integration into a multi-parameter device for on-line quality control analysis
The photospheric abundances of active binaries III. Abundance peculiarities at high activity level
We report the determination from high-resolution spectra of the atmospheric
parameters and abundances of 13 chemical species (among which lithium) in 8
single-lined active binaries. These data are combined with our previous results
for 6 other RS CVn systems to examine a possible relationship between the
photospheric abundance patterns and the stellar activity level. The stars
analyzed are generally found to exhibit peculiar abundance ratios compared to
inactive, galactic disk stars of similar metallicities. We argue that this
behaviour is unlikely an artefact of errors in the determination of the
atmospheric parameters or non-standard mixing processes along the red giant
branch, but diagnoses instead the combined action of various physical processes
related to activity. The most promising candidates are cool spot groups
covering a very substantial fraction of the stellar photosphere or NLTE effects
arising from nonthermal excitation. However, we cannot exclude the possibility
that more general shortcomings in our understanding of K-type stars (e.g.
inadequacies in the atmospheric models) also play a significant role. Lastly,
we call attention to the unreliability of the (V-R) and (V-I) colour indices as
temperature indicators in chromospherically active stars.Comment: Accepted for publication in A&A, 17 pages, 7 figures (6 in colour
Investigation of lung volume measurements in neonates using gas in scattering media absorption spectroscopy
We perform phantom and numerical studies of the changes in molecular oxygen and water vapor spectroscopic signals, showing the potential of measuring pulmonary volume changes with GASMAS technique in neonates
Brazilian guidelines for diagnosis, treatment and follow-up of primary cutaneous melanoma - part II
The last Brazilian guidelines on melanoma were published in 2002. Development in diagnosis and treatment made updating necessary. The coordinators elaborated ten clinical questions, based on PICO system. A Medline search, according to specific MeSH terms for each of the 10 questions was performed and articles selected were classified from A to D according to level of scientific evidence. Based on the results, recommendations were defined and classified according to scientific strength. The present Guidelines were divided in two parts for editorial and publication reasons. In this second part, the following clinical questions were answered: 1) which patients with primary cutaneous melanoma benefit from sentinel lymph node biopsy? 2) Follow-up with body mapping is indicated for which patients? 3) Is preventive excision of acral nevi beneficious to patients? 4) Is preventive excision of giant congenital nevi beneficious to patients? 5) How should stages 0 and I primary cutaneous melanoma patients be followed
Factors influencing elderly women's mammography screening decisions: implications for counseling
<p>Abstract</p> <p>Background</p> <p>Although guidelines recommend that clinicians consider life expectancy before screening older women for breast cancer, many older women with limited life expectancies are screened. We aimed to identify factors important to mammography screening decisions among women aged 80 and older compared to women aged 65–79.</p> <p>Methods</p> <p>Telephone surveys of 107 women aged 80+ and 93 women aged 65–79 randomly selected from one academic primary care practice who were able to communicate in English (60% response rate). The survey addressed the following factors in regards to older women's mammography screening decisions: perceived importance of a history of breast disease, family history of breast cancer, doctor's recommendations, habit, reassurance, previous experience, mailed reminder cards, family/friend's recommendations or experience with breast cancer, age, health, and media. The survey also assessed older women's preferred role in decision making around mammography screening.</p> <p>Results</p> <p>Of the 200 women, 65.5% were non-Hispanic white and 82.8% were in good to excellent health. Most (81.3%) had undergone mammography in the past 2 years. Regardless of age, older women ranked doctor's recommendations as the most important factor influencing their decision to get screened. Habit and reassurance were the next two highly ranked factors influencing older women to get screened. Among women who did not get screened, women aged 80 and older ranked age and doctor's counseling as the most influential factors and women aged 65–79 ranked a previous negative experience with mammography as the most important factor. There were no significant differences in preferred role in decision-making around mammography screening by age, however, most women in both age groups preferred to make the final decision on their own (46.6% of women aged 80+ and 50.5% of women aged 65–79).</p> <p>Conclusion</p> <p>While a doctor's recommendation is the most important factor influencing elderly women's mammography screening decisions, habit and reassurance also strongly influence decision-making. Interventions aimed at improving clinician counseling about mammography, which include discussions around habit and reassurance, may result in better decision-making.</p
Nanoenabling electrochemical sensors for life sciences applications
Electrochemical sensing systems are advancing into a wide range of new applications, moving from the traditional lab environment into disposable devices and systems, enabling real-time continuous monitoring of complex media. This transition presents numerous challenges ranging from issues such as sensitivity and dynamic range, to autocalibration and antifouling, to enabling multiparameter analyte and biomarker detection from an array of nanosensors within a miniaturized form factor. New materials are required not only to address these challenges, but also to facilitate new manufacturing processes for integrated electrochemical systems. This paper examines the recent advances in the instrumentation, sensor architectures, and sensor materials in the context of developing the next generation of nanoenabled electrochemical sensors for life sciences applications, and identifies the most promising solutions based on selected well established application exemplars
Long-term chromospheric activity of non-eclipsing RS CVn-type stars
Context. The IUE database provides a large number of UV high and
low-resolution spectra of RS CVn-type stars from 1978 to 1996. In particular,
many of these stars were monitored continuously during several seasons by IUE.
Aims. Our main purpose is to study the short and long-term chromospheric
activity of the RS CVn systems most observed by IUE: HD 22468 (V711 Tau, HR
1099, K1IV+G5V), HD 21242 (UX Ari, K0IV+G5V) and HD 224085 (II Peg, K2IV).
Methods. We first obtain the Mount Wilson index S from the IUE high and
low-resolution spectra. Secondly, we analyse with the Lomb-Scargle periodogram
the mean annual index S and the amplitude of its rotational modulation.
Results. For HD 22468 (V711 Tau, HR 1099), we found a possible chromospheric
cycle with a period of 18 years and a shorter cycle with a period of 3 years,
which could be associated to a chromospheric "flip-flop" cycle. The data of HD
224085 (II Peg) also suggest a chromospheric cycle of 21 years and a flip-flop
cycle of 9 years. Finally, we obtained a possible chromospheric cycle of 7
years for HD 21242 (UX Ari).Comment: accepted for publication in Astronomy and Astrophysic
Measurement of the Ratio of Branching Fractions B(D0 -> K+ pi-)/B(D0 -> K- pi+) using the CDF II Detector
We present a measurement of R_B, the ratio of the branching fraction for the
rare decay D0 -> K+ pi- to that for the Cabibbo-favored decay D0 -> K- pi+.
Charge conjugate decays are implicitly included. A signal of 2005 +/- 104
events for the decay D0 -> K+ pi- is obtained using the CDF II detector at the
Fermilab Tevatron collider. The data set corresponds to an integrated
luminosity of 0.35 1/fb produced in p-bar/p collisions at sqrt{s}=1.96 TeV.
Assuming no mixing, we find R_B = [ 4.05 +/- 0.21 (stat) +/- 0.11 (syst) ] x
10(-3). This measurement is consistent with the world average, and comparable
in accuracy with the best measurements from other experiments.Comment: 7 pages, 3 figure
Measurement of the Dipion Mass Spectrum in X(3872) -> J/Psi Pi+ Pi- Decays
We measure the dipion mass spectrum in X(3872)--> J/Psi Pi+ Pi- decays using
360 pb-1 of pbar-p collisions at 1.96 TeV collected with the CDF II detector.
The spectrum is fit with predictions for odd C-parity (3S1, 1P1, and 3DJ)
charmonia decaying to J/Psi Pi+ Pi-, as well as even C-parity states in which
the pions are from Rho0 decay. The latter case also encompasses exotic
interpretations, such as a D0-D*0Bar molecule. Only the 3S1 and J/Psi Rho
hypotheses are compatible with our data. Since 3S1 is untenable on other
grounds, decay via J/Psi Rho is favored, which implies C=+1 for the X(3872).
Models for different J/Psi-Rho angular momenta L are considered. Flexibility in
the models, especially the introduction of Rho-Omega interference, enable good
descriptions of our data for both L=0 and 1.Comment: 7 pages, 4 figures -- Submitted to Phys. Rev. Let
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