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X-ray polycrystalline diffraction was used to track progress toward improving the structural properties of SrS:(Eu,Sm) thin films. These thin films are used as the active layer of the ETOM (Electron Trapping Optical Memory) media. In this study conventional x-ray diffraction and x-ray reflectivity were used to evaluate the effect of two deposition parameters on film structures. Line broadening analysis performed using the Warren-Averbach technique showed the beneficial effects of a hydrogen sulfide reactive atmosphere and the RF magnetron sputtering technique on crystallite size and microstrain. A factor of five improvement in crystallite size and a factor of two reduction in microstrain was observed. Film thickness, density, and interfacial and surface roughnesses were determined for two SrS thin films. The sin2Ψ technique was used to determine the in-plane biaxial stress for two films prepared by different deposition techniques. These films exhibit inhomogeneous stress states with an average stress of less than IMPa.
Introduction: Medical journals are an essential venue for knowledge translation. Skilled reviewers and editors are required to ensure quality standards in research publications and yet postgraduate programs rarely include this training in their curricula. Imparting appropriate skills and developing capacity in journalship has thus proved challenging. The Canadian Journal of Emergency Medicine (CJEM) is the national journal for Emergency Medicine (EM) in Canada. The CJEM editorial board recently decided to provide longitudinal mentorship for junior academic faculty members and trainees through an editorial internship. The internship had three goals for participants: (1) introduce and develop the responsibilities and skills of a good editor; (2) enhance a career in academic EM; and, (3) galvanize future participation as a reviewer or editor in scientific publications. Methods: The senior editorial board of CJEM and the inaugural intern developed a one-year Editorial Internship that was launched in June 2017. The curricular framework was designed by current and prior CJEM senior editors from four Canadian universities, and was informed by similar programs in the United States. The curriculum was refined iteratively based on feedback and discussion between the senior editors and intern. The internship was designed for a single individual in the Canadian EM community, including residents, pediatric fellows and practicing emergency physicians. Results: To develop the responsibilities and skills of being a good editor, the intern performed six mentored reviews of manuscripts either under current review at CJEM or previous submissions identified as difficult peer review decisions. In addition, the intern learned about CJEM values and norms by participating in monthly videoconference meetings and quarterly editorial board meetings. To enhance an academic career, the intern was assigned two writing projects under the guidance of senior editors for publication in CJEM, and completed an online critical appraisal course. Conclusion: The inaugural editorial intern gained experience as an editor and produced scholarly work. We feel the internship met its first two goals, and CJEM has committed to continue the internship annually. The ultimate determination of whether the internship achieved its third goal will only be known after longitudinal tracking of participants career involvement in academic publishing and editing.
In this brief report, computed tomography perfusion (CTP) thresholds predicting follow-up infarction in patients presenting <3 hours from stroke onset and achieving ultra-early reperfusion (<45 minutes from CTP) are reported. CTP thresholds that predict follow-up infarction vary based on time to reperfusion: Tmax >20 to 23 seconds and cerebral blood flow <5 to 7 ml/min−1/(100 g)−1 or relative cerebral blood flow <0.14 to 0.20 optimally predicted the final infarct. These thresholds are stricter than published thresholds.
In developing countries, problems such as malnutrition and food insecurity are shifting from rural to urban areas because of rapid urbanization. However, regional variations in alimental food consumption within urban settings have often been ignored. Using survey data, our study examines regional patterns of expenditure on fresh vegetables, fruits, and peanut products in urban households of Ghana. After accounting for socioeconomic and demographic factors, food expenditure on fresh vegetables and peanut products and income elasticity vary significantly across major cities. Food distributors may adjust their marketing strategies, while policy makers should pay attention to possible disparities in urban areas.
This paper presents a new approach to simulate the propagation of elastic and cohesive cracks under mode-I loading based on the vector form intrinsic finite element method. The proposed approach can handle crack propagation without requiring global stiffness matrices and extra weak stiffness elements. The structure is simulated by mass particles whose motions are governed by the Newton's second law. Elastic and cohesive crack propagation are simulated by proposed VFIFE-J-integral and VFIFE-FCM methods, respectively. The VFIFE-J-integral method is based on vector form intrinsic finite element (VFIFE) and J-integral methods to calculate the stress intensity factors at the crack tips, and the VFIFE-FCM method combines VFIFE and fictitious crack models (FCM). When the stress state at the crack tip meets the fracture criterion, the mass particle at the crack tip is separated into two particles. The crack then extends in the plate until the plate splits into two parts. The proposed VFIFE-J-integral method was validated by elastic crack simulation of a notched plate, and the VFIFE-FCM method by cohesive crack propagation of a three point bending beam. As assembly of the global stiffness matrix is avoided and each mass particle motion is calculated independently, the proposed method is easy and efficient. Numerical comparisons demonstrate that the present results predicted by the VFIFE method are in agreement with previous analytical, numerical and experimental works.
Faster eating rates are associated with increased energy intake, but little is known about the relationship between children’s eating rate, food intake and adiposity. We examined whether children who eat faster consume more energy and whether this is associated with higher weight status and adiposity. We hypothesised that eating rate mediates the relationship between child weight and ad libitum energy intake. Children (n 386) from the Growing Up in Singapore Towards Healthy Outcomes cohort participated in a video-recorded ad libitum lunch at 4·5 years to measure acute energy intake. Videos were coded for three eating-behaviours (bites, chews and swallows) to derive a measure of eating rate (g/min). BMI and anthropometric indices of adiposity were measured. A subset of children underwent MRI scanning (n 153) to measure abdominal subcutaneous and visceral adiposity. Children above/below the median eating rate were categorised as slower and faster eaters, and compared across body composition measures. There was a strong positive relationship between eating rate and energy intake (r 0·61, P<0·001) and a positive linear relationship between eating rate and children’s BMI status. Faster eaters consumed 75 % more energy content than slower eating children (Δ548 kJ (Δ131 kcal); 95 % CI 107·6, 154·4, P<0·001), and had higher whole-body (P<0·05) and subcutaneous abdominal adiposity (Δ118·3 cc; 95 % CI 24·0, 212·7, P=0·014). Mediation analysis showed that eating rate mediates the link between child weight and energy intake during a meal (b 13·59; 95 % CI 7·48, 21·83). Children who ate faster had higher energy intake, and this was associated with increased BMI z-score and adiposity.
This paper presents a parameterized gait generator based on linear inverted
pendulum model (LIPM) theory, which allows users to generate a natural gait
pattern with desired step sizes. Five types of zero moment point (ZMP)
components are proposed for formulating a natural ZMP reference, where ZMP moves
continuously during single support phases instead of staying at a fixed point in
the sagittal and lateral plane. The corresponding center of mass (CoM)
trajectories for these components are derived by LIPM theory. To generate a
parameterized gait pattern with user-defined parameters, a gait planning
algorithm is proposed, which determines related coefficients and boundary
conditions of the CoM trajectory for each step. The proposed parameterized gait
generator also provides a concept for users to generate gait patterns with
self-defined ZMP references by using different components. Finally, the
feasibility of the proposed method is validated by the experimental results with
a teen-sized humanoid robot, David, which won first place in the sprint event at
the 20th Federation of International Robot-soccer Association (FIRA) RoboWorld
Single-walled carbon nanotube (SWNT) and conductive polymer composite were studied as a potential electrode candidate for plastic electronic devices such as organic light-emitting diodes (OLEDs) and solar cells. A novel conductive polymer, poly(2,7–9,9(di(oxy-2,5,8-trioxadecane))fluorene) (PFO), was synthesized and characterized as a surfactant to disperse SWNTs in solutions. The ethylene oxide (EO) side chain of rigid PFO backbone acts as a template to wrap around SWNTs in solution. Up to 0.02% (by weight) of SWNTs are stabilized and well separated in the solution phase. The carbon nanotube can be dispersed in solutions for over 4 mo. Transmission electron microscopy (TEM) images of solvent cast film suggest highly uniformed SWNT distribution incorporated in the conductive polymer matrix. Transmittance characterization shows the film is as transparent as indium tin oxide conducting glass. Conductivity measurement shows SWNTs can effectively inject charges into the PFO polymer matrix at low voltage. The current versus voltage profile of the SWNT/PFO composite film (2% SWNT in PFO by weight) shows that the majority current conducting is carried by SWNTs.
In this paper, we propose a tracking algorithm to detect power lines from millimeter-wave radar video. We propose a general framework of cascaded particle filters which can naturally capture the temporal correlation of the power line objects, and the power-line-specific feature is embedded into the conditional likelihood measurement process of the particle filter. Because of the fusion of multiple information sources, power line detection is more effective than the previous approach. Both the accuracy and the recall of power line detection are improved from around 68% to over 92%.
A buoyant vortex ring produced by an underwater bursting balloon was studied experimentally. The effect of dimensionless surface tension on characteristics including rise velocity, rate of expansion, circulation, trajectory, and lifetime of the vortex ring bubble was investigated. Results showed reasonable agreement with the literature on vortex rings produced by conventional approaches. It was observed that as the dimensionless surface tension increased, the rise velocity, the circulation and consequently the stability of the vortex ring bubble increased; however, the rate of expansion tends toward constant values. A semi-analytical model is proposed by modifying the drag-based model presented by Sullivan et al. (J. Fluid Mech., vol. 609, 2008, pp. 319–347) to make it applicable to buoyant vortex rings. The modified model suggests that the vortex ring expansion is essentially due to the buoyancy force. An expression is also derived for the circulation in terms of the initial volume of the balloon and the depth at which the balloon bursts.
Catalyst-free vapor phase transport was applied for the growth of ZnO nanoemitters. A single-crystalline ZnO:Al seed layer was deposited and used as a pseudo-catalyst. The desired morphology of nanostructures can be achieved by means of modifying the growth rates of crystal planes via adjustment in the growth conditions. The field emission characteristics of ZnO nanoemitters satisfied the Fowler-Nordheim relationship. The high aspect ratio of nanoemitters had a low turn-on electric field of 0.18 MV/m at emission current density of 0.1 μA/cm2. A stable electron emission with a variation of less than 14% was measured.
We conducted a systematic review summarizing data on incidence of high- and low-grade lesions in women with normal baseline cervical cytology, stratified by age (<30 and ⩾30 years), and baseline human papillomavirus (HPV) infection. Incidence of high- and low-grade lesions in women aged ⩾30 years with a baseline HPV infection increased over follow-up time (5–127 months), although incidence generally remained <10%. Without baseline HPV infection, incidence of high-grade lesions remained low over follow-up time (<5% over 5–122 months). Incidence of high-grade lesions in women aged ⩾30 years with baseline HPV infection appeared similar to that in women aged <30 years. In some women aged <30 years, high-grade lesions can develop relatively shortly after initial HPV infection. We observed an increase in low-grade lesions over time in women aged ⩾30 years with baseline HPV infection, potentially indicative of an HPV infection that is potentially progressing to higher grade lesions.
Thin silicate nanoplatelets, derived from the exfoliation of natural Sodium montmorillonite (Na+-MMT) clays, show an unexpected antimicrobial property. A physical trapping mechanism has been proposed because the clay nanoplatelets can indiscriminately inhibit the growth of a broad spectrum of bacteria, including drug-resistant species such as methicillin-resistance S. aureus (MRSA) and silver ion-resistant E. coli. The ability to generate singlet oxygen species was first observed for the clay platelets that showed a high-aspect-ratio geometric shape and the presence of surface ionic charges. By comparison, the pristine clay with a multilayered structure failed to generate any singlet oxygen species. The ability to emit singlet oxygen species provides direct evidence for the antimicrobial ability of clay through a non-chemical mechanism, which opens the potential for medical use.
High quality dilute nitride subcells for multijunction solar cells are achieved using GaInNAsSb. The effects on device performance of Sb composition, strain and purity of the GaInNAsSb material are discussed. New world records in efficiency have been set with lattice-matched InGaP/GaAs/GaInNAsSb triple junction solar cells and a roadmap to 50% efficiency with lattice-matched multijunction solar cells using GaInNAsSb is shown.
Carbapenem-resistant Enterobacteriaceae (CRE) are rapidly emerging in hospitals in the United States and are posing a significant threat. To better understand the transmission dynamics and the acquisition of resistant strains, a thorough analysis of epidemiologic and molecular characteristics was performed.
CRE isolated at Detroit Medical Center were analyzed from September 2008 to September 2009. blaKPC genes were investigated by polymerase chain reaction (PCR), and repetitive extragenic palindromic PCR (rep-PCR) was used to determine genetic similarity among strains. Epidemiologic and outcomes analyses were performed.
Ninety-two unique patient CRE isolates were recovered. Sixty-eight strains (74%) were Klebsiella pneumoniae, 7 were Klebsiella oxytoca, 15 were Enterobacter species, and 2 were Escherichia coli. Fifteen isolates (16%) were resistant to Colistin, 14 (16%) were resistant to tigecycline, and 2 were resistant to all antimicrobials tested. The mean ± standard deviation age of patients was 63 ± 2 years. Sixty patients (68%) were admitted to the hospital from long-term care facilities. Only 70% of patients received effective antimicrobial therapy when infection was suspected, with a mean time to appropriate therapy of 120 ± 23 hours following sample culturing. The mean length of hospitalization after sample culturing was 18.6 ± 2.5 days. Of 57 inpatients, 18 (32%) died in the hospital. Independent predictors for mortality were intensive care unit stay (odds ratio [OR], 15.8; P = .003) and co-colonization with CRE and either Acinetobacter baumannii or Pseudomonas aeruginosa (OR, 17.2; P = .006). Among K. pneumoniae CRE, rep-PCR revealed 2 genetically related strains that comprised 70% and 20% of isolates, respectively.
In this large U.S. cohort of patients with CRE infection, which reflects the modern continuum of medical care, co-colonization with CRE and A. baumannii or P. aeruginosa was associated with increased mortality. Two predominant clones of K. pneumoniae accounted for the majority of cases of CRE infection.
Electrical properties and leakage current mechanisms of perovskite CaZrO3 dielectric thin films have been studied in this paper. CaZrO3 thin films were deposited on Pt/SiO2/n-Si substrate by the sol-gel wet chemical technology, and then annealed at temperatures ranging from 550 to 700 °C for 1h in O2. The films with platinum (Pt) top and bottom electrodes were characterized with respect to the leakage current as a function of temperature and applied voltage. The CaZrO3 film annealed at 600 °C was amorphous and showed good electrical properties with a dielectric constant of about 15 and leakage current density of 10−8 A/cm2 at high applied electrical field of 2.5 MV/cm. The data can be interpreted via a Schottky barrier model. The conduction mechanism at low electric fields is due to Ohmic conduction. On the other hand Schottky mechanism dominates at the intermediate fields. The high dielectric constant, low leakage current density and high breakdown strength suggest that the CaZrO3 thin film is a promising candidate for high-k applications.
InGaN/GaN/AlGaN multiple quantum well light emitting diodes (MWQ LED's) with different levels of p-doping in the contact layer have been characterized using surface photovoltage spectroscopy (SPS). Due to the high sensitivity of the SPS technique to the electric field, there is a strong correlation between the p-doping level in the contact layer and the magnitude of the SPS signal originating from the MQW region. The experimental results are confirmed by a numerical simulation.
In this work, high quality silicon dioxide (SiO2) films were prepared by large-area plasmaenhanced chemical vapor deposition (LA-PECVD) using tetraethylorthosilicate(TEOS)-oxygen based chemistry. The effects of various short-time plasma treatments on these as-deposited TEOS oxide were also investigated. Different plasma treatments such as O2, N2O, and NH3 were used in our experiments. Electrical characteristics were exploited to examine the effects of plasma treatments. It was shown that after N2O, and NH3 plasma treatments, the electrical strength of oxide was enhanced. Besides, NH3 plasma treatment exhibited the highest enhancement efficiency. O2- plasma treatment, however, showed some harmful effects on the electrical properties of the TEOS oxide. The reliability tests including charge to breakdown (Qbd) and bias temperature stress (BTS) were also analyzed in these samples. Although better pre-stress characteristics were observed in those samples treated by NH3-plasma, samples with N2O plasma treatment showed superior stress endurance. Consequently, N2O plasma treatment seems to be the best candidate for future TFTs under the consideration of long-term reliability.