The aim of this work was to evaluate the effect of exposure of grass pea seeds to IR (infrared) radiation applied at varying time intervals on their mechanical properties, trypsin inhibitor activity, ...and reactive lysine content. Grass pea seeds cv. Derek were exposed to IR radiation at 180degreesC for 30, 60, 90, 120, and 180 s, respectively. Compared with that of raw seeds, IR heating of grass pea seeds reduced trypsin inhibitor activity. Reactive lysine proved to be relatively stable in the applied heating conditions. In addition, the process led to the reduction in the value of breaking load required for the destruction of a single seed, which may facilitate further processing, for example, flaking. Therefore, IR heating can be used in processing grass pea seeds. Keywords: grass pea, infrared radiation, reactive lysine, breaking load
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Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Ford, J. F., Maslowski, A. J., Redd, R. A. and Braby, L. A. Radiation Responses of Perfused Tracheal Tissue. Radiat. Res. 164, 487–492 (2005). We are using a novel perfusion system to examine the ...effects of radiation on a model respiratory tissue. Tracheas taken from young adult male Fischer 344 rats are embedded in a growth factor-enriched agarose matrix that is mounted in a special apparatus designed to allow growth medium to periodically wash the epithelial surface of the lumen. A comparison of the microarray expression profiles of freshly harvested tracheas and tracheas maintained in perfusion culture for 24 h shows no significant difference except for an increase in expression of a few metabolism- and surfactant-related genes. Perfusion culture samples exposed to 4 Gy of X rays show a lower than expected increase in expression for some cell cycle- and repair-related genes.
In a double-blind trial of streptokinase for acute myocardial infarction, 219 consecutive patients presenting with infarction within four hours (mean, 3.0 +/- 0.8) of the onset of chest pain were ...randomly assigned to treatment with streptokinase (1.5 million units) or placebo, given intravenously over 30 minutes. The primary end point of the study was left ventricular function in patients with first infarctions. Patients who could undergo beta-blockade also received intravenous propranolol. Heparin (for 48 hours) and a combination of low-dose aspirin and dipyridamole were administered to both groups until cineangiography was performed at three weeks. In the patients with first infarctions treated with streptokinase, the left ventricular ejection fraction was 6 percentage points higher (streptokinase vs. placebo, 59 +/- 10.5 vs. 53 +/- 13.5 percent; P less than 0.005), with benefit to patients with either anterior infarction (57 +/- 11.9 vs. 49 +/- 15.9 percent; P less than 0.05) or inferior infarction (60 +/- 9.1 vs. 55 +/- 11.3 percent; P less than 0.05). Left ventricular function was improved regardless of whether concomitant propranolol was given. Survival (at 30 days) was improved with streptokinase: 2 deaths occurred among 79 patients who received this drug, as compared with 12 deaths among 93 patients who received placebo (2.5 vs. 12.9 percent, P = 0.012). Rates of reinfarction (streptokinase vs. placebo, 3 vs. 1 percent) and requirements for surgery or angioplasty (7 vs. 5 percent) were similar in the two groups. We conclude that administration of intravenous streptokinase (1.5 million units) to patients with a first myocardial infarction results in improved left ventricular function and short-term survival.
In a double-blind trial comparing two thrombolytic agents as treatment for acute myocardial infarction, we randomized 270 consecutive patients an average (+/- SD) of 2.5 +/- 0.6 hours after the onset ...of chest pain from a first myocardial infarction--135 to receive intravenous streptokinase (1.5 million units over 30 minutes) and 135 to receive intravenous recombinant tissue plasminogen activator (rt-PA) (100 mg over three hours). The primary end point was left ventricular function as assessed by cineangiography performed three weeks after infarction. The effects of the two agents on left ventricular function were similar. The ejection fraction was identical (58 +/- 12 percent) in both groups. The end-systolic volume was 61 +/- 29 ml in the streptokinase group and 66 +/- 31 ml in the rt-PA group (P not significant). Patency rates at three weeks for the infarct-related artery were also similar (75 percent in the streptokinase group and 76 percent in the rt-PA group). Reinfarction rates at 30 days were the same (5 percent) in both groups. One patient had a fatal intracerebral hemorrhage 13 hours after receiving rt-PA, and another had a fatal cerebellar hemorrhage 21 hours after receiving rt-PA for reinfarction nine days after treatment with streptokinase. An intention-to-treat analysis revealed that mortality at 30 days was 3.7 percent in the rt-PA group as compared with 7.4 percent in the streptokinase group (P greater than 0.2). Follow-up for a mean of 9.0 months revealed no significant difference in survival; we observed 12 deaths (8.9 percent) in the streptokinase group and 8 deaths (5.9 percent) in the rt-PA group (P = 0.34). We conclude that rt-PA and streptokinase, in the doses given, have similar effects on left ventricular function after a first myocardial infarction. Because of the small number of deaths, it is not possible to determine whether their effects on mortality are similar.
Purpose:
To develop a rapid and accurate software tool for computing patient‐specific radiation dose maps of dose delivered from kV computed tomography (CT) scans.
Methods:
Monte Carlo methods ...currently provide the gold‐standard for calculating patient‐specific dose maps, but require immense computational resources to achieve sufficiently high statistical accuracy. To overcome this limitation, a deterministic method was implemented to solve the same underlying Boltzmann transport equation (BTE) that governs particle interactions and transport. Phase‐space was discretized according to spatial location, energy, and angle, and a deterministic finite element algorithm was applied to compute the object's photon fluence distribution, which does not exhibit stochastic noise. A computationally efficient GPU implementation for a standard workstation was developed, and comparison was made between the performance of the deterministic BTE solver and a standard Monte Carlo algorithm for a cone‐beam projection of a virtual anthropomorphic chest phantom.
Results:
The BTE solution and Monte Carlo results were in strong agreement with a relative root‐mean square error (RMSE) of 3.47%. Some larger differences existed at high‐contrast boundaries (e.g., air/water) and within the bone, and are under further investigation. Notably, the computation time of the BTE solver was 8 seconds, while to obtain the same level of statistical uncertainty with conventional Monte Carlo required 1200 CPU‐hours. Additionally, unlike Monte Carlo, the BTE computation time is only weakly dependent on the number of sources, making it extremely well‐suited for CT dose calculations. Therefore, the BTE‐based method is expected to offer a >30,000x speed increase compared to Monte Carlo for entire CT scans, even after application of variance reduction techniques and GPU implementation.
Conclusion:
The novel deterministic BTE solver offers a significantly faster alternative to Monte Carlo‐based methods for computing dose delivered by CT scans, which can enable estimation of patient‐specific organ doses for each CT examination performed.
Adam Wang, Alex Maslowski, Todd Wareing, and Josh Star‐Lack are employees of Varian Medical Systems.
Purpose:
To improve CBCT image quality for image-guided radiotherapy by applying advanced reconstruction algorithms to overcome scatter, noise, and artifact limitations
Methods:
CBCT is used ...extensively for patient setup in radiotherapy. However, image quality generally falls short of diagnostic CT, limiting soft-tissue based positioning and potential applications such as adaptive radiotherapy. The conventional TrueBeam CBCT reconstructor uses a basic scatter correction and FDK reconstruction, resulting in residual scatter artifacts, suboptimal image noise characteristics, and other artifacts like cone-beam artifacts. We have developed an advanced scatter correction that uses a finite-element solver (AcurosCTS) to model the behavior of photons as they pass (and scatter) through the object. Furthermore, iterative reconstruction is applied to the scatter-corrected projections, enforcing data consistency with statistical weighting and applying an edge-preserving image regularizer to reduce image noise. The combined algorithms have been implemented on a GPU. CBCT projections from clinically operating TrueBeam systems have been used to compare image quality between the conventional and improved reconstruction methods. Planning CT images of the same patients have also been compared.
Results:
The advanced scatter correction removes shading and inhomogeneity artifacts, reducing the scatter artifact from 99.5 HU to 13.7 HU in a typical pelvis case. Iterative reconstruction provides further benefit by reducing image noise and eliminating streak artifacts, thereby improving soft-tissue visualization. In a clinical head and pelvis CBCT, the noise was reduced by 43% and 48%, respectively, with no change in spatial resolution (assessed visually). Additional benefits include reduction of cone-beam artifacts and reduction of metal artifacts due to intrinsic downweighting of corrupted rays.
Conclusion:
The combination of an advanced scatter correction with iterative reconstruction substantially improves CBCT image quality. It is anticipated that clinically acceptable reconstruction times will result from a multi-GPU implementation (the algorithms are under active development and not yet commercially available).
All authors are employees of and (may) own stock of Varian Medical Systems.
To describe the long-term mortality of a complete national cohort of acute coronary syndrome (ACS) patients enrolled in 2002, to compare this with a national age, sex and Māori ethnicity matched ...population, and to assess the influence of baseline factors on the 12-year mortality.
We reviewed 721 patients with a discharge diagnosis of an ACS who were enrolled in the first New Zealand ACS audit group cohort over 14days in May 2002. We matched the cohort to the national mortality database using each patient’s unique national identity number.
Over a median follow-up of 12.7 years of 721 patients discharged with an ACS, overall mortality was 52%: ST-elevation myocardial infarction (STEMI) (58%), non-ST-elevation myocardial infarction (NSTEMI) (61%) and unstable angina pectoris (UAP) (42%) patients, p<0.0001. In an age-adjusted survival model, males had a 29% increased mortality rate compared to females with a hazard ratio of 1.29 (95% CI 1.04, 1.61, p=0.019). Over 12 years there were 339 (47%) deaths, compared to 284 (39%) deaths observed in the matched population. The standardised mortality ratio for patients admitted with an ACS in New Zealand is 1.3 (95% CI 1.2, 1.5) with eight patients per 100 not surviving to 12 years compared to this matched population.
The high mortality rate in this ACS cohort is a stark reminder of the prognostic implications of a presentation with an ACS. It emphasises the on-going need for optimal management of these patients throughout every stage of their initial treatment and subsequent on-going care.
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