574 research outputs found

    Lattice Heat Capacity of Mesoscopic Nanostructures

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    We present a rigorous full quantum mechanical model for the lattice heat capacity of mesoscopic nanostructures in various dimensions. Model can be applied to arbitrary nanostructures with known vibrational spectrum in zero, one, two, or three dimensions. The limiting case of infinitely sized multi-dimensional materials are also found, which are in agreement with well-known results. As examples, we obtain the heat capacity of fullerenes

    Bipolar Transistor Based on Graphane

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    Graphane is a semiconductor with an energy gap, obtained from hydrogenation of the two-dimensional grapheme sheet. Together with the two-dimensional geometry, unique transport features of graphene, and possibility of doping graphane, p and n regions can be defined so that p-n junctions become feasible with small reverse currents. Our recent analysis has shown that an ideal I-V characteristic for this type of junctions may be expected. Here, we predict the behavior of bipolar juncrion transistors based on graphane. Profiles of carriers and intrinsic parameters of the graphane transistor are calculated and discussed

    Dynamic Development Contests

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    Public, private, and not-for-profit organizations find advanced technology and product development projects challenging to manage due to the time and budget pressures, and turn to their development partners and suppliers to address their development needs. We study how dynamic development contests with enriched rank-based incentives and carefully-tailored information design can help these organizations outsource their development projects at the minimum project lead time by stimulating competition among suppliers. We show that an organization can use dynamically adjusted flexible rewards to achieve the absolute minimum expected project lead time at a significantly lower cost than a fixed-reward policy. Importantly, our flexible-reward policy pays the absolute minimum expected reward (i.e., achieves the first best). We further study the case where the organization does not have sufficient budget to offer a reward that attains the absolute minimum expected lead time. We propose that in this case, the organization can dynamically increase the contest reward until its budget constraint binds and then use information sharing as a strategic tool to incentivize suppliers. Specifically, we propose an easy-to-implement random-update policy where the organization periodically monitors the status of suppliers at random times and immediately discloses any partial progress. We show that such a random-update policy outperforms other canonical information disclosure strategies. Our results indicate that dynamic rewards and strategic information disclosure are powerful tools to help organizations outsource their development needs swiftly and cost effectively

    Examining clinical decision support integrity: is clinician self-reported data entry accurate?

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    The aim of this study was to assess the accuracy of clinician-entered data in imaging clinical decision support (CDS). We used CDS-guided CT angiography (CTA) for pulmonary embolus (PE) in the emergency department as a case example because it required clinician entry of d-dimer results which could be unambiguously compared with actual laboratory values. Of 1296 patients with CTA orders for suspected PE during 2011, 1175 (90.7%) had accurate d-dimer values entered. In 55 orders (4.2%), incorrectly entered data shielded clinicians from intrusive computer alerts, resulting in potential CTA overuse. Remaining data entry errors did not affect user workflow. We found no missed PEs in our cohort. The majority of data entered by clinicians into imaging CDS are accurate. A small proportion may be intentionally erroneous to avoid intrusive computer alerts. Quality improvement methods, including academic detailing and improved integration between electronic medical record and CDS to minimize redundant data entry, may be necessary to optimize adoption of evidence presented through CDS

    Electrocatalytic Oxidation and Determination of Insulin at Rhodamine B –Multi-walled Carbon Nanotubes Modified Glassy Carbon Electrode

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    AbstractThe modified electrode surface was provided with the electropolymerization of the rhodamine B in the presence of carbon nanotube (CNT). The modified electrode offers dramatic improvements in the stability and sensitivity of voltammetric measurements of insulin compared to the bare and rhodamine B modified glassy carbon electrodes. The enhanced electrocatalytic activity towards insulin is indicated from lowering the potential of the oxidation process (starting around 0.75 vs. Ag/AgCl) and the substantially higher sensitivity over the entire potential range. A linear dynamic range (100–600nM) was achieved with a detection limit of 5nM. The accuracy of the modified electrode was indicated by insulin recovery test in the real samples as human plasma and pharmaceutical samples

    On multiplication Γ-modules

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    In this article, we study some properties of multiplication M Γ - modules and their prime M Γ -submodules. We verify the conditions of ACC and DCC on prime M Γ -submodules of multiplication M Γ - module

    Effect of alendronate on post-traumatic osteoarthritis induced by anterior cruciate ligament rupture in mice.

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    IntroductionPrevious studies in animal models of osteoarthritis suggest that alendronate (ALN) has antiresorptive and chondroprotective effects, and can reduce osteophyte formation. However, these studies used non-physiologic injury methods, and did not investigate early time points during which bone is rapidly remodeled prior to cartilage degeneration. The current study utilized a non-invasive model of knee injury in mice to investigate the effect of ALN treatment on subchondral bone changes, articular cartilage degeneration, and osteophyte formation following injury.MethodsNon-invasive knee injury via tibial compression overload or sham injury was performed on a total of 90 mice. Mice were treated with twice weekly subcutaneous injections of low-dose ALN (40 μg/kg/dose), high-dose ALN (1,000 μg/kg/dose), or vehicle, starting immediately after injury until sacrifice at 7, 14 or 56 days. Trabecular bone of the femoral epiphysis, subchondral cortical bone, and osteophyte volume were quantified using micro-computed tomography (μCT). Whole-joint histology was performed at all time points to analyze articular cartilage and joint degeneration. Blood was collected at sacrifice, and serum was analyzed for biomarkers of bone formation and resorption.ResultsμCT analysis revealed significant loss of trabecular bone from the femoral epiphysis 7 and 14 days post-injury, which was effectively prevented by high-dose ALN treatment. High-dose ALN treatment was also able to reduce subchondral bone thickening 56 days post-injury, and was able to partially preserve articular cartilage 14 days post-injury. However, ALN treatment was not able to reduce osteophyte formation at 56 days post-injury, nor was it able to prevent articular cartilage and joint degeneration at this time point. Analysis of serum biomarkers revealed an increase in bone resorption at 7 and 14 days post-injury, with no change in bone formation at any time points.ConclusionsHigh-dose ALN treatment was able to prevent early trabecular bone loss and cartilage degeneration following non-invasive knee injury, but was not able to mitigate long-term joint degeneration. These data contribute to understanding the effect of bisphosphonates on the development of osteoarthritis, and may support the use of anti-resorptive drugs to prevent joint degeneration following injury, although further investigation is warranted

    Assessing 2 D-dimer age-adjustment strategies to optimize computed tomographic use in ED evaluation of pulmonary embolism

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    STUDY OBJECTIVE: Validate the sensitivity and specificity of 2 age adjustment strategies for d-dimer values in identifying patients at risk for pulmonary embolism (PE) compared with traditional D-dimer cutoff value (500 ng/mL) to decrease inappropriate computed tomography pulmonary angiography (CTPA) use. METHODS: This institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective study included all adult emergency department patients evaluated for PE over a 32-month period (1/1/11-8/30/13). Only patients undergoing CTPA and D-dimer testing were included. We used a validated natural language processing algorithm to parse CTPA radiology reports and determine the presence of acute PE. Outcome measures were sensitivity and specificity of 2 age-adjusted D-dimer cutoffs compared with the traditional cutoff. We used chi2 tests with proportional analyses to assess differences in traditional and age-adjusted (agex10 ng/mL) D-dimer cutoffs, adjusting both by decade and by year. RESULTS: A total 3063 patients with suspected PE were evaluated by CTPA during the study period, and 1055 (34%) also received d-dimer testing. The specificity of age-adjusted D-dimer values was similar or higher for each age group studied compared with traditional cutoff, without significantly compromising sensitivity. Overall, had decade age-adjusted cutoffs been used, 37 CTPAs could have been avoided (19.6% of 189 patients aged \u3e60 years with Wells score50 years with Wells scor

    Life Cycle Assessment of Municipal Waste Management System (Case Study: Karaj, Iran)

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    LCA has been defined as a tool for evaluating the environmental burdens and potential impacts that can be applied to municipal solid waste management systems for determine the optimum municipal solid waste (MSW) management strategy.To investigate the Waste Management system strategyof Karaj City we used LCA method. Three scenarios were defined and compared based on environmental burden include water pollution, air pollution, consumed energy and waste residues.. For each of these scenarios, an ecological indicator was achieved from checklist values. From the environmental point of view, results show that recycling is one of the best alternatives for Waste Management. Furthermore, composting has an important role in alleviating the load of pollutants and energy usage in the Waste Management system. ©JASEMKeywords: Waste Management system, LCA, Kara

    Efficacy of Hi-Lo Evac Endotracheal Tube in Prevention of Ventilator-Associated Pneumonia in Mechanically Ventilated Poisoned Patients

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    Background. Ventilator-associated pneumonia (VAP) is the most common health care-associated infection. To prevent this complication, aspiration of subglottic secretions using Hi-Lo Evac endotracheal tube (Evac ETT) is a recommended intervention. However, there are some reports on Evac ETT dysfunction. We aimed to compare the incidence of VAP (per ventilated patients) in severely ill poisoned patients who were intubated using Evac ETT versus conventional endotracheal tubes (C-ETT) in our toxicology ICU. Materials and Methods. In this clinical randomized trial, 91 eligible patients with an expected duration of mechanical ventilation of more than 48 hours were recruited and randomly assigned into two groups: (1) subglottic secretion drainage (SSD) group who were intubated by Evac ETT (n = 43) and (2) control group who were intubated by C-ETT (n = 48). Results. Of the 91 eligible patients, 56 (61.5) were male. VAP was detected in 24 of 43 (55.8) patients in the case group and 23 of 48 (47.9) patients in the control group (P = 0.45). The most frequently isolated microorganisms were S. aureus (54.10) and Acinetobacter spp. (19.68). The incidence of VAP and ICU length of stay were not significantly different between the two groups, but duration of intubation was statistically different and was longer in the SSD group. Mortality rate was less in SSD group but without a significant difference (P = 0.68). Conclusion. The SSD procedure was performed intermittently with one-hour intervals using 10 mL syringe. Subglottic secretion drainage does not significantly reduce the incidence of VAP in patients receiving MV. This strategy appears to be ineffective in preventing VAP among ICU patients. © 2016 Ahmad Ghoochani Khorasani et al
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