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High temperature X-ray diffraction (HTXRD) was used to determine the peritectic melting sequence of BI2Sr2CaCu2O8 (Bi-2212) and Bi-2212+20 wt.% Ag thick films on MgO substrates. The optimized sample preparation technique includes tape casting the powders to form 10μm thick films, and reducing the residual carbon concentration to 1600 ppm by careful thermal treatment before the HTXRD measurements. Lattice parameter analyses were used to determine the compositions of solid solutions present in the partially-melted state. Pour phases form during melting Bi-2212 or Bi-2212 + Ag, including an unidentified phase, (C0,4Sr0,6CuO2, (Ca1,4Sr0,6)CuO3, and (Sr,Ca)0.
OBJECTIVES/SPECIFIC AIMS: Describe the framework for tier advancement of research professionals. Describe the various forms of assessments of competencies. How competencies are used to provide transparency into professional development opportunities. Discuss the results of the first tier advancement opportunity for research staff. METHODS/STUDY POPULATION: These processes were developed at Duke, an academic medical center with over 2000 active clinical research protocols and 300 new clinical trials per year. Roughly 500 employees are categorized into tiered classifications, allowing them opportunities for advancement through competency testing. Approximately 10% opted for tier testing, and their results will be shared. RESULTS/ANTICIPATED RESULTS: Competency assessments were developed for all 42 of Duke’s research professional competencies, some using 2 modalities of testing. Almost 12% of the research professionals classified in tiered positions opted to attempt the tier advancement process. Of those, 37 completed, and the vast majority reached their desired tier. Results by competency will be provided. DISCUSSION/SIGNIFICANCE OF IMPACT: The use of objectively assessed competencies is an important step in the development of a workforce. By (1) maintaining alignment with industry standards for competencies, (2) holding staff to a high bar, and (3) offering a consistent approach to career growth, Duke is working to develop and maintain a workforce that supports high quality research.
Malignant gliomas (MG) are highly invasive and aggressive brain tumors. Despite the current standard of care, the prognosis for patients with MG is abysmal– highlighting the need for novel, more effective treatment options to combat this aggressive disease. Oncolytic virus (OV) therapy is an advancing treatment option that harnesses tumor-selective viruses to kill cancer cells while simultaneously facilitating a systemic anti-tumor immune response. Many studies have noted synergistic effects when OV’s are combined with radiotherapy in preclinical cancer models, warranting further investigation of this multi-modal approach. Image-guided radiotherapy (IGRT) uses computer-modulated imaging techniques to precisely deliver ionizing radiation to treat cancer. Despite the precision IGRT offers, cancer cells can still be ‘missed’ due to tumor microextensions or radioresistant cell populations– such as glioma stem cells or therapy-induced senescent cancer cells –and may contribute to recurrence or progression. Here we propose to combine our mCherry-tagged mutant vaccinia virus (deltaF4L-deltaJ2R-mCherry), which exhibits tumor-selectivity due to mutations in key viral nucleotide biosynthesis genes, with IGRT executed using state-of-the-art Small Animal Radiation Research Platform (SARRP) technology. We hypothesize that combining deltaF4L-deltaJ2R-mCherry with IGRT will produce better tumor control than either modality alone, by generating additive or synergistic effects in which IGRT destroys the majority of the tumor mass while our OV seeks out and targets any remaining cancer cells that have been missed or are resistant to radiotherapy.
We present new results on RR Lyrae stars and anomalous Cepheids in the Draco dwarf spheroidal galaxy. We have increased the number of double-mode RR Lyrae stars and found three new anomalous Cepheids. With period-magnitude and period-amplitude diagrams, we discuss the Oosterhoff classification of Draco. Contradictory results were found in that Draco appears to contain both Oosterhoff I and II type RR Lyrae populations.
Freshwater migratory shrimps, an important component of tropical aquatic ecosystems, are vulnerable to land-use change during their upstream and downstream migrations. At La Selva Biological Station in the Sarapiquí region of Costa Rica, shrimp population data were collected between 1988 and 1989, before massive land-use change occurred downstream that could potentially affect shrimp recruitment upstream. Using generalized linear models and a Bayesian inference framework, the relative abundance of Macrobrachium olfersi between recent (2008–2011) and historical time periods (1988–1989) was compared in three stream reaches. Shrimp relative abundance in two stream reaches within the protected area of La Selva was relatively constant yearly and between recent post-disturbance (2008–2011) and historical pre-disturbance (1988–89) time periods. In contrast, a stream reach bordered by pasture accessible to fishermen, showed an 87% decrease in relative abundance between recent and historical time periods suggesting site-level disturbance, possibly from fishing. The lack of change between historical and contemporary sampling periods within interior-forest stream reaches suggests that shrimp populations in protected forested reaches are resistant or resilient to certain land-use changes occurring downstream.
This paper describes a study that investigated the efficacy of modifications to the trailing end of the externally mounted advanced targeting forward looking infrared pod (ATFLIR) on the store separation characteristics of the F/A-18C aircraft. Prior work by Godiksen suggests that the trailing end of the geometrically similar targeting forward looking infrared pod (TFLIR) is the likely source of shock waves that can adversely impact the trajectory of a recently released store. In our study five different modifications to the aft end of the ATFLIR were analysed using computational fluid dynamics (CFD). The two most promising designs, an ogive shape such as that used in artillery shells and rockets, and a simpler extended but truncated cone shape were then further investigated. The moments that these trailing shapes produced on an adjacent released store were compared. CFD analysis revealed that the simpler cone shape resulted in weaker shocks from the aft end of the pod with a resultant smaller adverse moment on the store. While there is an extensive history of using CFD to predict store separation behavior, results from our study should be compared with wind tunnel data in order to validate the CFD simulations.
Ellipsometry is normally used to characterize layered structures that have uniform properties laterally across the area of the probe beam. In this study, pulsed laser deposition of ZnO films was found to have highly nonuniform growth properties in the lateral directions. We were able to account for the effects of the nonuniform growth on in-situ ellipsometric data, by considering two dynamic growth models.
Microwave sintering of Si3N4—based materials showed improved densification as compared to samples heated conventionally under similar conditions. Accelerated nitridation of Si in the microwave furnace to produce Si3N4 was also observed. Dense Si3N4, annealed by microwave heating, exhibited enhanced grain growth; however preferential coupling of the microwave power to the grain—boundary phases in the present experiments resulted in their degradation.
Variable Angle of incidence Spectroscopic Ellipsometry (VASE) is a sensitive, nondestructive method of determining optical constants, layer thicknesses, alloy compositions and other parameters. We model the VASE data for a sample containing a 20 period Al0 5Ga0 5As-GaAs superlattice, to obtain the effective index of refraction (n) and e tinction coefficient (k) of the superlattice layer. The room temperature VASE spectra contain strong, sharp features at the e-hh(1), e-lh(1) and e-hh(2) excitonic tran-sition energies. In addition, VASE was used to characterize more compli-cated layered structures, which also contained superlattices.
Spectroscopic ellipsometry (SE) measurements were made during and after electron cyclotron resonance (ECR) etching of GaAs. The spectral range for ex situ measurements, 1.24–5 eV, included the E1, E1+A1 critical points. The Ej, Ei+Aj structure was red shifted by about 50 meV, and broadened, by etching with a mixture of methane, argon, and hydrogen. Exposure to a pure H2 plasma caused greater red shifting and broadening, while a pure Ar ECR plasma produced only a slight red shift. The red shift is consistent with an increase in lattice constant of the order of 1%, in the top 10-30 nm. Broadening is consistent with crystalline lattice damage.
We have employed a 32 atom cyclic-cluster and the Modified Intermediate Neglect of Differential Overlap (MINDO/3) method to compute the lattice constant, band structure, heat of formation and other properties of cubic boron nitride, diamond and silicon nitride. The computational scheme we have employed will permit studies of defects in these materials.
In situ ellipsometry at selected wavelengths in the spectral range 280 nm to 1000 nnn was performed during the rf bias assisted electron cyclotron resonance (ECR) etching of bulk silicon, GaAs, InP, and GaAs/AlGaAs/GaAs, and InGaAs/InP layered strcutures by a CCl2F2 based etch gas.
While real time thickness changes for bulk materials cannot be determined ellipsometrically, some insight into the etch mechanism may be gained by observing the effect of the process on the surface dynamically, and after the etch process has been completed. Monitoring of the layered structures during etching can provide a real time measure of the amount of material remaining in the layer being etched, and provide tight process control.
This paper discusses the use of Ink Jet printing techniques to dispense small (50 to 75 micrometer diameter) particles of molten eutectic solder individually at programmable dispense rates from drop on demand to several thousand per second. Alternative jet dispensing techniques are discussed. The technology could allow the selective application of programmable amounts of solder on precision circuit boards and wafer substrates, while avoiding the high cost and flexibility limits associated with hard tooling. Large solder features can be constructed by dispensing individual droplets and relying on surface tension to draw them together to form a large single feature. Alternatively, columnar features can be created by successively dispensing solder droplets at the same site, allowing time between successive droplets to avoid forming a single large spherical feature.
Several potential application areas in industry are discussed along with some of the issues associated with the projected performance of the method in the accuracy and speed domains.
Previously, a hard core/soft shell computer model was developed to simulate the overlap and percolation of the interfacial transition zones surrounding each aggregate in a mortar or concrete. The aggregate particles were modelled as spheres with a size distribution representative of a real mortar or concrete specimen. Here, the model has been extended to investigate the effects of aggregate shape on interfacial transition zone percolation, by modelling the aggregates as hard ellipsoids, which gives a dynamic range of shapes from plates to spheres, to fibers. For high performance concretes, the interfacial transition zone thickness will generally be reduced, which will also affect their percolation properties. This paper presents results from a study of the effects of interfacial transition zone thickness and aggregate shape on these percolation characteristics.
For light-emitting porous Si there has been a severe problem with instability and degradation of the light emission. We report that a stabilization of the emission intensity and the peak energy can be achieved in air by a proper laser irradiation, In-situ photoluminescence measurements were performed to monitor the degradation and stabilization process under different conditions and parameters, such as laser power, laser wavelength and environment (ambient atmosphere of certain gas or ultra high vacuum). We found oxygen is the major cause for the emission degradation in this laser enhanced adsorption process, and the laser heating effect can be excluded. For a comparison we study the reversible thermal heating and quenching process. We also discuss microwave and ECR plasma passivation results.