1,995 research outputs found
Direct Calorimetric Studies on the Heats of Ionization of Oxygenated and Deoxygenated Hemoglobin
Abstract The total heats of ionization, Qo and Qr, of bovine, human, and horse oxygenated and deoxygenated hemoglobin (O2Hb and Hb) have been directly measured by the rapid calorimetric method over the pH range from 5.7 to 9.0, at 12–28°. The most extensive determinations have been those on bovine hemoglobin: above about pH 6.6 the thermal titration curve for Hb lies systematically above that for O2Hb by about 600 cal, this difference presisting practically unchanged up to the most alkaline pH (8.7) studied. The two thermal titration curves cross at approximately pH 6.3, below which the O2Hb curve lies above the Hb curve by an increasing amount (up to 1,000 cal). The fact that Qr remains greater than Qo at pH 8.7, at which the absolute value of Qr is about 11,000 cal, implies that the heme-linked group, which ionizes in this pH range in the case of Hb, must have a heat of ionization, Qr, of around 11,000 cal. This figure, which was confirmed by an approximate method of calculation, lies outside the range usually attributed to the heat of ionization of imidazole or its derivatives. There is some indication, from a comparison of the difference between the two thermal titration curves for human Hb and O2Hb at approximately pH 7.3, that (Qr - Qo) is of the order of 4,000 cal, Qo being the heat of ionization of the corresponding heme-linked group in O2Hb. The results thus support the conclusions reached in the adjoining paper by Rossi-Bernardi and Roughton on the effect of temperature on the oxygen-linked ionizations of hemoglobin. The relation of the present studies to the cognate effects of pH on the heat of oxygenation of hemoglobin is briefly indicated
Proteus: A Hierarchical Portfolio of Solvers and Transformations
In recent years, portfolio approaches to solving SAT problems and CSPs have
become increasingly common. There are also a number of different encodings for
representing CSPs as SAT instances. In this paper, we leverage advances in both
SAT and CSP solving to present a novel hierarchical portfolio-based approach to
CSP solving, which we call Proteus, that does not rely purely on CSP solvers.
Instead, it may decide that it is best to encode a CSP problem instance into
SAT, selecting an appropriate encoding and a corresponding SAT solver. Our
experimental evaluation used an instance of Proteus that involved four CSP
solvers, three SAT encodings, and six SAT solvers, evaluated on the most
challenging problem instances from the CSP solver competitions, involving
global and intensional constraints. We show that significant performance
improvements can be achieved by Proteus obtained by exploiting alternative
view-points and solvers for combinatorial problem-solving.Comment: 11th International Conference on Integration of AI and OR Techniques
in Constraint Programming for Combinatorial Optimization Problems. The final
publication is available at link.springer.co
Corpus luteum blood flow evaluation on Day 21 to improve the management of embryo recipient herds
AbstractThe aim of the present study was to use blood flow evaluation of the CL at 14 days after embryo transfer to detect nonpregnant animals and optimize the management of bovine recipients. The estrous cycle was synchronized in 165 recipients, and the day of expected ovulation was considered to be Day 0. Embryo transfer was performed 7 days later, on Day 7. On Day 21, pregnancy was diagnosed on the basis of blood flow evaluation of the CL (DG21—predictive diagnostic). To validate this methodology, visual scores for blood flow were compared to objective data extracted from CL ultrasound images recorded in the Doppler mode. The size was also evaluated using recorded images of the CL in the B mode. Blood samples were also collected for further analysis of the progesterone (P4) concentration. The diagnosis of pregnancy was confirmed at 35 days after estrus (DG35—definitive diagnostic). The DG21 showed that 55.2% (90 of 163) of the animals were presumptively pregnant, and this value was higher (P < 0.04) than that obtained at DG35 (43.6%, 71 of 163). The predictive diagnostic achieved moderate specificity (79.3%) for the detection of pregnancy, but most importantly, high sensitivity (100%) for the detection of nonpregnant recipients. The overall accuracy of the diagnosis was 88.3%. The P4 concentrations were different (P < 0.02) and correlated with each visual score assigned for the CL size. Visual scores for CL blood flow were also efficient (P < 0.0001) to distinguish animals with different levels of P4; however, P4 concentrations were higher for scores 1 and 2 (high and regular blood flow, respectively) than those for score 3 (low blood flow). This technique showed high sensitivity and facilitated the early detection of nonpregnant animals. The DG21 would allow about 79.3% of nonpregnant animals to be resynchronized 9 to 14 days earlier, when compared to conventional management based on pregnancy diagnosis at Days 30 to 35
Social Support and Depressive Symptoms in the Context of COVID-19 Lockdown: The Moderating Role of Attachment Styles
Determining the Gluon Distributions in the Proton and Photon from Two-Jet Production at HERA
Two-jet production from the direct photon contribution at HERA is a sensitive
measure of the small- gluon in the proton. We propose measurements of ratios
of the jet cross-sections which will clearly distinguish between gluons with or
without singular behaviour at small . Furthermore, we show that analogous
ratio measurements for the resolved photon contribution provide a sensitive way
of determining the gluon distribution in the photon.Comment: Rutherford Appleton Laboratory report RAL-93-071 7 pages 3 figs Fig2
and Fig3 included as psfile
Dietary Inflammatory Index and Renal Cell Carcinoma Risk in an Italian Case-Control Study
Background: The relation between diet-related inflammation and renal cell carcinoma (RCC) has not been investigated. Methods: In this study, we explored the association between the dietary inflammatory index (DII) and RCC in an Italian case-control study conducted between 1992 and 2004. Cases were 767 patients with incident, histologically confirmed RCC. Controls were 1534 subjects admitted to the same hospitals as cases for various acute, nonneoplastic conditions. The DII was computed based on dietary intake assessed using a reproducible and valid 78-item food frequency questionnaire. Odds ratios (ORs) were estimated through logistic regression models conditioned on age, sex, and center, and adjusted for recognized confounding factors, including total energy intake. Results: Subjects in the highest quartile of DII scores (i.e., with the most proinflammatory diets) had a higher risk of RCC compared to subjects in the lowest quartile [OR 1.41, 95% confidence interval (CI) 1.02, 1.97; p-trend = 0.04)]. Apparently stronger associations were observed among females (OR 1.68, 95% CI 0.93, 3.03), subjects aged <60yr (OR 1.77, 95% CI 1.05, 2.98), body mass index 25 kg/m(2) (OR 1.64, 95% CI 1.07, 2.51), and ever smokers (OR 1.66, 95% CI 1.08, 2.57), in the absence of significant heterogeneity. Conclusion: A proinflammatory diet is associated with increased RCC risk
Scintillation and charge extraction from the tracks of energetic electrons in superfluid helium-4
An energetic electron passing through liquid helium causes ionization along
its track. The ionized electrons quickly recombine with the resulting positive
ions, which leads to the production of prompt scintillation light. By applying
appropriate electric fields, some of the ionized electrons can be separated
from their parent ions. The fraction of the ionized electrons extracted in a
given applied field depends on the separation distance between the electrons
and the ions. We report the determination of the mean electron-ion separation
distance for charge pairs produced along the tracks of beta particles in
superfluid helium at 1.5 K by studying the quenching of the scintillation light
under applied electric fields. Knowledge of this mean separation parameter will
aid in the design of particle detectors that use superfluid helium as a target
material.Comment: 10 pages, 8 figure
The SWAP EUV Imaging Telescope Part I: Instrument Overview and Pre-Flight Testing
The Sun Watcher with Active Pixels and Image Processing (SWAP) is an EUV
solar telescope on board ESA's Project for Onboard Autonomy 2 (PROBA2) mission
launched on 2 November 2009. SWAP has a spectral bandpass centered on 17.4 nm
and provides images of the low solar corona over a 54x54 arcmin field-of-view
with 3.2 arcsec pixels and an imaging cadence of about two minutes. SWAP is
designed to monitor all space-weather-relevant events and features in the low
solar corona. Given the limited resources of the PROBA2 microsatellite, the
SWAP telescope is designed with various innovative technologies, including an
off-axis optical design and a CMOS-APS detector. This article provides
reference documentation for users of the SWAP image data.Comment: 26 pages, 9 figures, 1 movi
Statistical nature of non-Gaussianity from cubic order primordial perturbations: CMB map simulations and genus statistic
We simulate CMB maps including non-Gaussianity arising from cubic order
perturbations of the primordial gravitational potential, characterized by the
non-linearity parameter . The maps are used to study the characteristic
nature of the resulting non-Gaussian temperature fluctuations. We measure the
genus and investigate how it deviates from Gaussian shape as a function of
and smoothing scale. We find that the deviation of the non-Gaussian
genus curve from the Gaussian one has an antisymmetric, sine function like
shape, implying more hot and more cold spots for and less of both
for . The deviation increases linearly with and also
exhibits mild increase as the smoothing scale increases. We further study other
statistics derived from the genus, namely, the number of hot spots, the number
of cold spots, combined number of hot and cold spots and the slope of the genus
curve at mean temperature fluctuation. We find that these observables carry
signatures of that are clearly distinct from the quadratic order
perturbations, encoded in the parameter . Hence they can be very useful
tools for distinguishing not only between non-Gaussian temperature fluctuations
and Gaussian ones but also between and type
non-Gaussianities.Comment: 18+1 page
Higher mean cerebral oxygen saturation shortly after extracorporeal cardiopulmonary resuscitation in patients who regain consciousness
Introduction: In cardiac arrest, cerebral ischemia and reperfusion injury mainly determine the neurological outcome. The aim of this study was to investigate the relation between the course of cerebral oxygenation and regain of consciousness in patients treated with extracorporeal cardiopulmonary resuscitation (ECPR). We hypothesized that rapid cerebral oxygenation increase causes unfavorable outcomes. Methods: This prospective observational study was conducted in three European hospitals. We included adult ECPR patients between October 2018 and March 2020, in whom cerebral regional oxygen saturation (rSO2) measurements were started minutes before ECPR initiation until 3 h after. The primary outcome was regain of consciousness, defined as following commands, analyzed using binary logistic regression. Results: The sample consisted of 26 ECPR patients (23% women, Agemean 46 years). We found no significant differences in rSO2 values at baseline (49.1% versus 49.3% for regain versus no regain of consciousness). Mean cerebral rSO2 values in the first 30 min after ECPR initiation were higher in patients who regained consciousness (38%) than in patients who did not regain consciousness (62%, odds ratio 1.23, 95% confidence interval 1.01–1.50). Conclusion: Higher mean cerebral rSO2 values in the first 30 min after initiation of ECPR were found in patients who regained consciousness.</p
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