26,544 research outputs found
Gibbs entropy and irreversible thermodynamics
Recently a number of approaches has been developed to connect the microscopic
dynamics of particle systems to the macroscopic properties of systems in
nonequilibrium stationary states, via the theory of dynamical systems. This way
a direct connection between dynamics and Irreversible Thermodynamics has been
claimed to have been found. However, the main quantity used in these studies is
a (coarse-grained) Gibbs entropy, which to us does not seem suitable, in its
present form, to characterize nonequilibrium states. Various simplified models
have also been devised to give explicit examples of how the coarse-grained
approach may succeed in giving a full description of the Irreversible
Thermodynamics. We analyze some of these models pointing out a number of
difficulties which, in our opinion, need to be overcome in order to establish a
physically relevant connection between these models and Irreversible
Thermodynamics.Comment: 19 pages, 4 eps figures, LaTeX2
Assessing a 600-mg Loading Dose of Clopidogrel 24 Hours Prior to Pipeline Embolization Device Treatment
Background:
Clopidogrel/aspirin antiplatelet therapy routinely is administered 7-10 days before pipeline aneurysm treatment. Our study assessed the safety and efficacy of a 600-mg loading dose of clopidogrel 24 hours before Pipeline Embolization Device (PED) treatment.
Methods: In this retrospective cohort study, we included patients treated with PED from October 2010 to May 2016. A total of 39.7% (n = 158) of patients were dispensed a loading dose of 650 mg of aspirin plus at least 600 mg of clopidogrel 24 hours preceding PED deployment, compared to 60.3% (n = 240) of patients who received 81-325 mg of aspirin daily for 10 days with 75 mg of clopidogrel daily preprocedurally. The mean follow-up was 15.8 months (standard deviation [SD] 12.4 months). modified Rankin Scale (mRS) was registered before the discharge and at each follow-up visit. To control confounding, we used multivariable logistic regression and propensity score conditioning.
Results: Of 398 patients, the proportion of female patients was ~16.5% (41/240) in both groups and shared the same mean of age ~56.46 years. ~12.2% (mean = 0.09; SD = 0.30) had a subarachnoid hemorrhage. 92% (mean = 0.29; SD = 0.70) from the pretreatment group and 85.7% (mean = 0.44; SD = 0.91) of the bolus group had a mRS ≤2. In multivariate analysis, bolus did not affect the mRS score, P = 0.24. Seven patients had a long-term recurrence, 2 (0.83%; mean = 0.01; SD = 0.10) of which from the pretreatment group. In a multivariable logistic regression, bolus was not associated with a long-term recurrence rate (odds ratio [OR] 1.91; 95% confidence interval [CI] 0.27-13.50; P = 0.52) or with thromboembolic accidents (OR 0.99; 95% CI 0.96-1.03; P = 0.83) nor with hemorrhagic events (OR 1.00; 95% CI 0.97-1.03; P = 0.99). Three patients died: one who received a bolus had an acute subarachnoid hemorrhage. The mean mortality rate was parallel in both groups ~0.25 (SD = 0.16). Bolus was not associated with mortality (OR 1.11; 95% CI 0.26-4.65; P = 0.89). The same associations were present in propensity score-adjusted models.
Conclusions: In a cohort receiving PED, a 600-mg loading dose of clopidogrel should be safe and efficacious in those off the standard protocol or showing \u3c30% platelet inhibition before treatment
Accuracy assessment of Tri-plane B-mode ultrasound for non-invasive 3D kinematic analysis of knee joints
BACKGROUND Currently the clinical standard for measuring the motion of the bones in knee joints with sufficient precision involves implanting tantalum beads into the bones. These beads appear as high intensity features in radiographs and can be used for precise kinematic measurements. This procedure imposes a strong coupling between accuracy and invasiveness. In this paper, a tri-plane B-mode ultrasound (US) based non-invasive approach is proposed for use in kinematic analysis of knee joints in 3D space. METHODS The 3D analysis is performed using image processing procedures on the 2D US slices. The novelty of the proposed procedure and its applicability to the unconstrained 3D kinematic analysis of knee joints is outlined. An error analysis for establishing the method's feasibility is included for different artificial compositions of a knee joint phantom. Some in-vivo and in-vitro scans are presented to demonstrate that US scans reveal enough anatomical details, which further supports the experimental setup used using knee bone phantoms. RESULTS The error between the displacements measured by the registration of the US image slices and the true displacements of the respective slices measured using the precision mechanical stages on the experimental apparatus is evaluated for translation and rotation in two simulated environments. The mean and standard deviation of errors are shown in tabular form. This method provides an average measurement precision of less than 0.1 mm and 0.1 degrees, respectively. CONCLUSION In this paper, we have presented a novel non-invasive approach to measuring the motion of the bones in a knee using tri-plane B-mode ultrasound and image registration. In our study, the image registration method determines the position of bony landmarks relative to a B-mode ultrasound sensor array with sub-pixel accuracy. The advantages of our proposed system over previous techniques are that it is non-invasive, does not require the use of ionizing radiation and can be used conveniently if miniaturized.This work has been supported by School of Engineering & IT, UNSW Canberra, under Research Publication Fellowship
War of the Worlds Revisited: The Effect of Watching The Day After on Mood State
In the fall of 1983, The Day After, a fictional account of a nuclear attack on a civilian population, was broadcast on television in the United States and viewed by I00 million Americans . The Day After was said to differ from previous movie treatments of nuclear war by the vividness with which it forced its audience to experience the ground zero effects of a nuclear blast on human beings (I) . In what was described as the most horrifically searing footage ever to pass a network censor, the audience was shown group immolation, a carnage of mass vaporization and graphic images of death (I). It was widely predicted that this movie would have stressful psychological effects because it dealt with a potentially real disaster. Warnings of possible psychiatric side effects of the film were issued by the American Psychiatric Association , the American Academy of Child Psychiatry, the American Academy of Pediatrics, and the American Broadcasting Company (1,2,3). So seriously were these warnings taken that the Federal Emergency Management Agency increased its staffing in anticipation of the movie\u27s psychological fallout (2). After the movie was shown, however, there was little systematic documentation of its psychological effects on the public. Since similarly graphic movies addressing the effects of nuclear war continue to be released and a replanned for the future, we feel the issue of the psychological effects of these films remains salient
Guadecitabine, in combination with Cyclophosphamide, promotes anti- cancer immunity in BALB/c mice bearing 4T1 mouse mammary carcinoma
Background: The extremely high mortality rate of patients diagnosed with triple negative breast cancer makes it one of the deadliest forms of cancer. Due to the heterogenous nature of tumors, complete clearance is not achieved and clonal selection occurs resulting in tumor cells evading the immune system. I aim to design a therapeutic intervention that is able to elicit an effective immune response against the tumor and instill immunological memory to eradicate primary and metastatic lesions. I hypothesize that the combination of Guad and Cyp will synergize and promote anticancer immunity via increased expression of neo-tumor antigens and depletion of MDSCs and T-regs. Methods: Guadecitabine (Guad), is a second-generation DNA methyltransferase inhibitor (DMNTi) that has been reported to increase antigenicity and deplete myeloid-derived suppressor cells (MDSC’s). Cyclophosphamide (Cyp) is a chemotherapy that has been shown to deplete regulatory T-cells (T-regs). Both MDSD’s and T-regs suppress antitumor immunity. BALB/c mice were challenged with 4T1 tumor cells subcutaneously in the mammary fat pad region. 4T1-bearing mice were administered low-dose Guad and Cyp for ten consecutive days. Tumor growth curves, tumor-infiltrating lymphocytes (TILs) were measured and MDSC’s and T- regs levels were assessed by flow cytometry. Results: Results from this experiment showed significant synergy between Guad and Cyp with both drugs reducing the tumor size over monotherapy. Conclusions: Further analysis of the data along with future experiments will elucidate if this synergy is driven by the depletion of MDSC’s and T-regs alone or the increase in tumor antigenicity inducing increased numbers of TILs.https://scholarscompass.vcu.edu/gradposters/1078/thumbnail.jp
The dynamic efficiency costs of common-pool resource exploitation
We conduct the first empirical investigation of common-pool resource users' dynamic and strategic behavior at the micro level using real-world data. Fishermen's strategies in a fully dynamic game account for latent resource dynamics and other players' actions, revealing the profit structure of the fishery. We compare the fishermen's actual and socially optimal exploitation paths under a time-specific vessel allocation policy and find a sizable dynamic externality. Individual fishermen respond to other users by exerting effort above the optimal level early in the season. Congestion is costly instantaneously but is beneficial in the long run because it partially offsets dynamic inefficiencies
Water quality management for domestic rainwater harvesting systems in Fiji
© 2015 IWA Publishing. Health risks from drinking rainwater are relatively small in the developing world context, but action is needed to ensure water safety. Water safety plans (WSPs) use an approach to manage water quality that has shown signs of success with public and communal water supplies, but relatively little research has been done to investigate the application of WSPs to self-supply systems. The aim of this paper is to investigate the primary issues surrounding appropriate water quality management of domestic rainwater harvesting (DRWH) systems in Fiji and consider how the principles of WSPs can be applied in this context. A qualitative research design was followed, utilising semi-structured interviews with 34 rural households and six key informants, sanitary inspections of DRWH systems and thematic data analysis. A number of challenges, including limited government resources and the limited knowledge and casual attitudes of rural rainwater consumers, constrain the practicality of adopting conventional WSPs at the household level, but steps for improvement can be taken
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