Number Of Ml Research Articles

Linear Atomic Cluster Expansion Force Fields for Organic Molecules: Beyond RMSE.

We demonstrate that fast and accurate linear force fields can be built for molecules using the atomic cluster expansion (ACE) framework. The ACE models parametrize the potential energy surface in terms of body-ordered symmetric polynomials making the functional form reminiscent of traditional molecular mechanics force fields. We show that the four- or five-body ACE force fields improve on the accuracy of the empirical force fields by up to a factor of 10, reaching the accuracy typical of recently proposed machine-learning-based approaches. We not only show state of the art accuracy and speed on the widely used MD17 and ISO17 benchmark data sets, but we also go beyond RMSE by comparing a number of ML and empirical force fields to ACE on more important tasks such as normal-mode prediction, high-temperature molecular dynamics, dihedral torsional profile prediction, and even bond breaking. We also demonstrate the smoothness, transferability, and extrapolation capabilities of ACE on a new challenging benchmark data set comprised of a potential energy surface of a flexible druglike molecule.

A pragmatic approach to adjusting early instrumental local magnitudes for seismic hazard assessments in Australia

Prior to the development of Australian-specific magnitude formulae, the 1935 magnitude correction factors by Charles Richter—originally developed for southern California—were almost exclusively used to calculate earthquake magnitudes throughout Australia prior to the 1990s. Due to the difference in ground-motion attenuation between southern California and much of the Australian continent, many earthquake magnitudes from the early instrumental era are likely to have been overestimated in the Australian earthquake catalogue. A method is developed that adjusts local magnitudes (ML) using the difference between the original (inappropriate) magnitude formulae (or look-up tables) and the Australian-specific formulae at a distance determined by the nearest recording station likely to have recorded the earthquake. Nationally, these adjustments have reduced the number of earthquakes of ML ≥ 4.5 in the early instrumental catalogue by approximately 25% since 1900, while the number of ML ≥ 5.0 earthquakes has reduced by approximately 32% over the same time period. The reduction in the number of moderate-to-large-magnitude earthquakes over the instrumental period yields long-term earthquake rates that are more consistent with present-day rates, since the development of Australian-specific magnitude formulae (approximately 1990). The adjustment of early instrumental magnitudes to obtain consistently derived earthquake catalogue is important for seismic hazard assessments.

Change in Creatinine Clearance Over Time Following Upper Abdominal Irradiation

To investigate the change in creatinine clearance (CrCl) over time following upper abdominal radiation utilizing a dose-volume histogram (DVH) multivariate analysis. The study population included 125 patients with gastrointestinal malignancy treated with abdominal radiation therapy at our institution between 1994 and 2006, with available creatinine and DVH information. Kidney dose-volume data collected included mean kidney dose, volume of kidney irradiated, V5, V10, and V20 of total kidney volume, and number of mL of kidney greater than and less than 20 Gy. With a median follow-up of 2.4 years, and a mean kidney dose of 16.2 Gy, a significant correlation between decrease in CrCl and irradiated kidney volume observed was noted for all DVH parameters. The strongest correlations were found when using V5, V10, and number of mL of kidney treated to greater than 20 Gy. There was no significant change in number of antihypertensive medications taken by patients over time, and no relationship between outcome variables and pre-existing comorbidities. This is the first study that we are aware of comparing DVH data with measurement of renal toxicity. We show significant correlations between dose and volume irradiated and decline in renal function. This will be clinically useful when determining a treatment plan for patients with borderline preradiation CrCl and provides evidence that minimizing radiation to the kidney could have important clinical ramifications.

HAZGRIDX: earthquake forecasting model for ML≥ 5.0 earthquakes in Italy based on spatially smoothed seismicity

We present a five-year, time-independent, earthquake-forecast model for earthquake magnitudes of 5.0 and greater in Italy using spatially smoothed seismicity data. The model is called HAZGRIDX, and it was developed based on the assumption that future earthquakes will occur near locations of historical earthquakes; it does not take into account any information from tectonic, geological, or geodetic data. Thus HAZGRIDX is based on observed earthquake occurrence from seismicity data, without considering any physical model. In the present study, we calculate earthquake rates on a spatial grid platform using two declustered catalogs: 1) the Parametric catalog of Italian earthquakes (Catalogo Parametrico dei Terremoti Italiani, CPTI04) that contains the larger earthquakes from MW 7.0 since 1100; and 2) the Italian seismicity catalogue (Catalogo della Sismicita Italiana, CSI 1.1) that contains the small earthquakes down to ML 1.0, with a maximum of ML 5.9, over the past 22 years (1981-2003). The model assumes that earthquake magnitudes follow the Gutenberg-Richter law, with a uniform b-value. The forecast rates are presented in terms of the expected numbers of ML>5.0 events per year for each grid cell of about 10 km × 10 km. The final map is derived by averaging the earthquake potentials that come from these two different catalogs: CPTI04 and CSI 1.1. We also describe the earthquake occurrences in terms of probabilities of occurrence of one event within a specified magnitude bin, DM0.1, in a five year time period. HAZGRIDX is one of several forecasting models, scaled to five and ten years, that have been submitted to the Collaboratory for the Study of Earthquake Probability (CSEP) forecasting center in ETH, Zurich, to be tested for Italy.

Change in Creatinine Clearance Over Time Following Upper Abdominal Irradiation: A Dose Volume Histogram Multivariate Analysis

OBJECTIVES To investigate the change in creatinine clearance (CrCl) over time following upper abdominal radiation utilizing a dose-volume histogram (DVH) multivariate analysis. METHODS The study population included 125 patients with gastrointestinal malignancy treated with abdominal radiation therapy at our institution between 1994 and 2006, with available creatinine and DVH information. Kidney dose-volume data collected included mean kidney dose, volume of kidney irradiated, V5, V10, and V20 of total kidney volume, and number of mL of kidney greater than and less than 20 Gy. RESULTS With a median follow-up of 2.4 years, and a mean kidney dose of 16.2 Gy, a significant correlation between decrease in CrCl and irradiated kidney volume observed was noted for all DVH parameters. The strongest correlations were found when using V5, V10, and number of mL of kidney treated to greater than 20 Gy. There was no significant change in number of antihypertensive medications taken by patients over time, and no relationship between outcome variables and pre-existing comorbidities. CONCLUSIONS This is the first study that we are aware of comparing DVH data with measurement of renal toxicity. We show significant correlations between dose and volume irradiated and decline in renal function. This will be clinically useful when determining a treatment plan for patients with borderline preradiation CrCl and provides evidence that minimizing radiation to the kidney could have important clinical ramifications.

Magnetic properties of MBE structures using fcc Co/Cu(001) and bcc Fe/Cu(001) (abstract)

We have used ferromagnetic resonance and surface magneto-optic Kerr effect to investigate the magnetic anisotropies in face-centered-cubic fcc Cu/Co/Cu(001) structures. We have found that Cu/Co/Cu structures possess large magnetic anisotropies. The twofold perpendicular anisotropy results in a strong easy plane (4πMeff = 4πMs + Hu ∼ 40 kOe). The perpendicular uniaxial anisotropy is only weakly dependent on Co film thickness. Hu = 25.4, 23.7, and 17.7 kOe in 3-, 4-, and 10-ML-thick Co films, respectively. The twofold perpendicular anisotropy in fcc Co/Cu/Cu structures is caused by the lateral expansion and vertical contraction of fcc Co(001) ultrathin films. The in-plane fourfold anisotropy in fcc Cu/Co/Cu(001) structures has its easy axis along the [110] crystallographic direction. The fourfold in-plane anisotropy is large (2K1/Ms ∼ 1 kOe) and weakly dependent on Co film thickness. Fe(001) can be grown epitaxially on fcc Co(001) and results in a significant change in the magnetic properties. In Cu/4Co/3Fe/Cu(001) multilayer (integers describe the number of ML) the perpendicular anisotropy changes its sign and is very weak (Hu = −1.5 kOe). The in-plane fourfold anisotropy is also appreciably decreased (2K1/Ms = 0.4 kOe). Cu/4Co/6Cu/<b>4Co<e>/Cu(001) trilayers are coupled antiferromagnetically. However, this coupling is smaller (J=−0.07 ergs/cm2) compared to bcc Fe/Cu/Fe structures. The exchange coupling in Co/Cu/Co trilayers depends strongly on details of the total structure, e.g., the sample Cu/4Co/6Cu/<b>4Co<e>/3Fe/Cu is ferromagnetically coupled (J∼0.1 ergs/cm2). The exchange coupling in bcc Fe/Cu/Fe(001) trilayers oscillates with increasing Cu thickness (oscillatory period of 10 ML). However, no evidence of symmetric oscillations was found.

The role of titratable acidity in acid aerosol-induced bronchoconstriction.

We evaluated the importance of pH, titratable acidity, and specific chemical composition in acid aerosol-induced bronchoconstriction in 8 asthmatic subjects. We administered aerosols of HCl and H2SO4 at pH 2.0 in an unbuffered state and buffered with glycine. The buffered acids were given in order of increasing titratable acidity (defined as the number of ml of 1 N NaOH required to neutralize 100 ml of acid solution to pH 7.0). Each set of buffered or unbuffered acid aerosols was given on a separate day and each aerosol was inhaled through a mouthpiece during 3 min of tidal breathing. Bronchoconstriction was assessed by measurement of specific airway resistance (SRaw) before and after inhalation of each aerosol. SRaw increased by more than 50% above baseline in 1 of 8 subjects after inhalation of unbuffered HCl and in no subjects after inhalation of unbuffered H2SO4, even at pH 2.0. In contrast, SRaw increased by greater than 50% in all 8 subjects after inhalation of HCl and glycine at pH 2.0 and 7 of 8 subjects after inhalation of H2SO4 and glycine at pH 2.0. The mean titratable acidity required to increase SRaw by 50% above baseline was calculated for each challenge by linear interpolation; these values for H2SO4 and glycine (5.1 ml of 1 N NaOH) and HCl and glycine (2.2 ml of 1 N NaOH) were slightly, but significantly, different (p = 0.01) and were considerably higher than the titratable acidity of the unbuffered acids at pH 2 (1.0 ml of 1 N NaOH).(ABSTRACT TRUNCATED AT 250 WORDS)

Moment‐magnitude relations in theory and practice

The observation that motivates this study is the difference in c values in moment‐magnitude relations of the form log MO = cML + d between central and southern California. This difference is not at all related to geographical area; rather, it results from positive curvature in the log MO ‐ ML plane and the relatively large number of ML<5 earthquakes in the central California data set. With the prescription that the far‐field shear waves from which ML is taken be finite‐duration, band‐limited, white Gaussian noise in acceleration, we can estimate ML as a function of MO alone, by fixing the arms stress drop at 100 bars and ƒmax at 15 Hz. These model calculations fit available California moment‐magnitude data for 0≲ML≲7,1017≲MO≲1028 dyne cm with striking accuracy. This range in source strength is entire: earthquakes with MO≥1028 dyne cm are unlikely to occur in California, and earthquakes with ML<0 cannot be recorded in California, at least under ordinary conditions of recording earthquakes at ordinary hypocentral depths. More fundamentally, the remarkably good fit of model to data implies that the arms stress drop of 100 bars (to a factor of 2 or so) is a stable and pervasive feature of all (ML≳2 1/2) California earthquakes whose spectral corner frequency lies in the “visible” bandwidth, ƒ0≤ƒmax.

Velocity of oxygen uptake by partly saturated adult and fetal human red cells

The rate of oxygen uptake by human adult and fetal red cells at 37 C was measured at saturations from zero up to 75% using a double-beam stopped-flow apparatus. Results were expressed in two ways: as k' c , the velocity constant for O 2 uptake by the cells, and as O standard the number of ml of O 2 ( stpd) which would be taken up in 1 minute per torr of P o 2, difference between the outside and inside of the red cells, by blood with an O 2 capacity of 20 vol%. At zero saturation, k' c for adult cells was 99 and for fetal cells was 89 millimolar −1 sec −. At low saturations there was little change in adult or fetal k' c but at higher saturations k' c rose and at 75 % saturation was 3–4 times its value at zero saturation. In fetal cells, k' c was about 10 % less than for adult cells. This difference was statistically significant at low saturations but at higher saturations there was much scatter in the results and the difference between adult and fetal cells was not significant. As saturation rose 0 showed little or no change up to 75% saturation. Theoretical analysis of the factors affecting k' c suggested that its rise with increasing SO 2 was due to a lowering of the concentration of intracellular deoxyhemoglobin rather than to any increase in reaction rate of oxygen with the hemoglobin molecule.

Study of a Proposed International Standard for Blood Coagulation Factor IX

An International Collaborative Study was organized to establish a standard for factor IX. Two freeze-dried concentrate preparations, C1 and C2, and one freeze-dried plasma P were compared with each other, with fresh normal plasmas and with local standards in 13 laboratories. One of the concentrate preparations (C1) contained heparin and this gave rise to non-parallel assays in laboratories testing concentrate C1 in dilutions containing more than 0.05 i.u. of heparin per ml. Assays of factor IX showed good precision for both plasma and concentrate in all laboratories; no systematic effect of method, operator or day of assay was detected. The plasma preparation P and the concentrate preparation C2 were compared with 59 individual fresh normal plasma samples, and a mean potency ratio of 0.78 (95% confidence limits 0.73-0.84) for plasma and 5.62(95% confidence limits 5.13-6.16) for the concentrate C2 obtained. Only 21 estimates of concentrate C1 in terms of fresh plasma were obtained giving a mean potency ratio of 3.85 (95% confidence limits 1.87-7.92). The estimated loss of potency for freeze-dried plasma stored at -20 degrees C is approximately 0.4% per year. The concentrate C2 is apparently more stable and only very small losses occurred even at higher storage temperatures. All participants agreed that the preparation C2 would be suitable to serve as an International Standard for factor IX; they also agreed that the figure assigned for the unitage should be based on the number of ml of 'average fresh normal plasma' estimated to contain the factor IX activity of one ampoule of the preparation. It is proposed to recommend to the World Health Organization that the preparation of factor IX concentrate C2, in ampoules coded 72/32, be considered for establishment as the International Standard for factor IX, and that the international unit for factor IX be assigned on the basis of 5.62 units per ampoule of this preparation.

Microdetermination of phosphate with EDTA

An indirect microdetermination of phosphate via EDTA titration is described, which can be applied to minerals, soils, fertilizers, biological samples, drugs and organo-phosphorus compounds. The method is based on the precipitation of phosphate as the very insoluble silver orthophosphate (K sp = 1.3 × 10 −20), dissolution of this precipitate in a solution of potassium cyanonickelate and titration of the nickel displaced by silver. The phosphate content is obtained indirectly by multiplying the number of ml of the titrant by a factor. The method takes about an hour after the phosphate is brought into solution. The accuracy is about 1% for samples containing 5–50 mg PO 4 3− and about 3–5% for samples with 100 to 5000 μg PO 4 3−.

Increased capillary diffusion capacity for small ions in skeletal muscle in long-term diabetics.

The disappearance rates of locally injected radioactive extracellular ions were studied in hyperemic human skeletal muscle (m. tibialis ant.) in 7 non-diabetics, 4 recently-diagnosed juvenile diabetics and 7 long-term juvenile diabetics with clinical manifestations of diabetic angiopathy. 24Na+ and 131I− were employed as tracers. The local blood flow was estimated by the 133Xenon clearance method.The capillary diffusion capacity, CDC, (Renkin's permeability-surface area product PS) was calculated in terms of the unidirectional flux of the tracers: CDC is the number of ml of interstitial fluid completely rinsed of tracer in the (imaginary) situation of infinitely high capillary blood flow, i.e. when no back-diffusion of tracer occurs.The average values for CDCNa and CDCI were found to be highly significantly increased (p<0.001) in the long-term diabetic group as compared to non-diabetics and recently-diagnosed diabetics: CDCNa=5.8; 4.2; 4.0 and CDCI=8.7; 6.4; 6.2 ml interstitial fluid per 100 g skeletal mu...

Variation in Tooth Position Following Extraction of First Molars in Relation To Incidence and Distribution of Dental Caries

In the course of dental examinations of over 8,000 vocational school pupils during a period of 3 years, 3 outstanding conditions were noted: (1) The frequent loss of first permanent molars; (2) changes in positions of first and second premolars and second molar in the jaw quadrants from which the first permanent molars had been extracted and (3) a high incidence of exteeth (Teeth showing physical abnormalities acquired since their eruption; e.g., caries, fillings, redecay, roots remaining, extractions, etc.). Full maxillary and mandibular dental impressions were taken and casts made of 500 boys and girls, 15 to 19 years of age, who were found to have had from 1 to 4 first molar teeth extracted (Table I). Additional groups of boys and girls in the same age range who had not lost any of the first molars were also studied for purposes of control and comparison. Altogether, 1940 boys and girls were studied, embracing the various ethnic, economic, social and intellectual components of the school population of Greater New York. Table I shows the number and percentage of children by age groups, from 15 to 19 years, with 1 to all 4 Ml's extracted; the total number of cases in each age group; the total number in each category having one, two, three or four Ml's extracted per case; the total number of cases studied; the total number of Ml's extracted, and the average number of Ml's extracted per case in each age group, as well as the average number of Ml's extracted per case for the group of 500.