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In this work, the effects of post-deposition annealing in forming gas ambient on the structure of the Al2O3/GaN interface are investigated. Using capacitance–voltage (C–V) and conductance–frequency (G–f) measurements, the quality of Al2O3/GaN metal–insulator–semiconductor (MIS) devices subjected to different annealing conditions was assessed. Annealing at 350°C for 10 and 20 min resulted in the lowest density of trap states (

A non-thermal method for removal of surface damage created by dry etching has previously been documented or n-GaN, but no such effort has been reported for p-GaN. In this study, Ga-polar p-GaN films were subjected to inductively coupled plasma reactive ion etching, creating damage near the surface and causing an inversion of the carrier type and concentration from + 5.5 × 1012 cm−2 to − 8.8 × 1010 cm−2, as measured by Hall effect. An application of the carrier-type-selective photoelectrochemical (PEC) etching technique using a KOH and K2S2O8 etch chemistry is employed in order to remove etch-face damage and recover the underlying p-GaN. We show the type selectivity of the PEC etching technique, demonstrating electroless etching of n-GaN while no interaction of the same etch chemistry with p-GaN is observed. Further, surface analysis shows that the PEC etch removes a surface layer from dry-etched p-GaN and increases its roughness substantially, from 0.64 nm to 71 nm RMS.

The diffusion behavior of Mg in Mg/N co-implanted GaN is investigated in response to a set of annealing conditions and methodologies, namely, 1000 °C/30 min thermal anneal, by high-temperature pulsed gyrotron microwave annealing at 1420 or 1500 °C, or by thermal and microwave annealing, sequentially. After 1000 °C annealing, the diffusion of Mg in GaN is found to be negligible, as measured by secondary ion mass spectrometry. Annealing by gyrotron microwave annealing alone induces the diffusion of Mg at a rate on the order of 10−12 cm2/s. However, the use of a thermal anneal before microwave gyrotron annealing reduces this rate by an order of magnitude to 10−13 cm2/s. We find that a model that considers Mg diffusion from an inhomogeneous medium that contains a defect-rich implanted region near-surface to a relatively pristine region below the implant range better explains the observed diffusion behavior than a conventional model that assumes a homogeneous medium. By analyzing the diffusion behavior using the Boltzmann–Matano method, we present a discussion of reduction in [VGa] by thermal annealing at 1000 °C, leading to a suppressed diffusion coefficient during subsequent high-temperature annealing relative to diffusion after 1420/1500 °C annealing alone. This effect holds potential for improvement in the precision of selectively doped regions for future applications based on the (Al)GaN material system. An improved field profile control in real devices can increase the breakdown and current-handling capabilities in power electronic applications.

In this chapter, the authors, former school and district leaders, submit that COVID-19 is a force that has caused collective sight and accelerated momentum relative to shifts we have always known we needed to make in education but haven't yet made at scale. Those shifts, manifested in instructional practice, equitable systems, and the strategic integration of technology, represent an urgency COVID-19 has revealed as an absolute. The authors argue that too often we have hidden behind readiness as a barrier to translating urgency to the lived experience of learners. COVID-19 has shown us our readiness matters little in a global pandemic. Ready or not, educators will respond in the face of unprecedented circumstances. How then, might educators become the force COVID-19 has been to ensure continued momentum?

We report here our latest results of achieving high quantum efficiency (QE) N-polar GaN photocathodes through engineering of bulk and interfacial impurity concentrations. The photocathode structures studied consist of an N-polar p-GaN absorbing layer with 10 nm u-GaN cap layer. An increase in QE from 0.27% to 10.1% is observed for photocathodes grown without a regrowth interface between p-GaN and u-GaN cap layers compared to an identical structure with a regrown interface. SIMS is used to identify impurities at the regrowth interface, which cause lower QE due to scattering and modification of the electric field. The QE is further increased to 26.6% through a 2x increase in hole concentration when the structure is grown on a high hillock density template. This work demonstrates a combined approach that has the promise of advancing toward and surpassing performance of current state-of-the-art photocathodes in the UV range.

GaN samples were implanted with Be and annealed in different conditions in order to activate the shallow BeGa acceptor. Low-temperature photoluminescence spectra were studied to find BeGa-related defects in the implanted samples. A yellow band with a maximum at about 2.2 eV (the YLBe band) was observed in nearly all samples protected with an AlN cap during the annealing and in samples annealed under ultrahigh N2 pressure. A green band with a maximum at 2.35 eV (the GL2 band), attributed to the nitrogen vacancy, was the dominant defect-related luminescence band in GaN samples annealed without a protective AlN layer. The ultraviolet luminescence (UVLBe) band with a maximum at 3.38 eV attributed to the shallow BeGa acceptor with the ionization energy of 0.113 eV appeared in implanted samples only after annealing at high temperatures and ultrahigh N2 pressure. This is the first observation of the UVLBe band in Be-implanted GaN, indicating successful activation of the BeGa acceptor.

Here we present for the first time the use of gyrotron beam for selective annealing/activation of implanted Mg in bulk GaN films. Samples with 1 μm uGaN epi-Iayer grown by MOCVD on HVPE bulk n+GaN substrates were implanted with Mg (1 x 1019 cm−3) to a target depth of 500 nm. A systematic investigation of annealing temperature, N 2 overpressure, surface capping layer, and sample orientation to the beam are presented. Post-implantation, volumetric lattice deformation was recovered by performing continuous annealing at temperatures $>$ 1100 °C for 30 s. Both AIN capped and uncapped samples were studied. It is shown that the surface of uncapped GaN samples which were annealed at 1100 °C in 40 bar N 2 overpressure remained intact. Photoluminescence spectroscopy was performed and confirmed the incorporation of Mg in substitutional sites with this technique, along with formation of large density of nitrogen vacancy defects.

Ductile slender reinforced masonry shear walls (DSRMSWs) designed and detailed according to modern seismic design provisions, such as those prescribed by the Canadian masonry design code CSA S304-14, are expected to demonstrate ductile performance when subjected to earthquake effects. These walls have shown good energy dissipation characteristics similar to ductile slender reinforced concrete (RC) shear walls and are used as the seismic-force-resisting system (SFRS) for contemporary buildings in Canada and other countries. These walls are usually slender, with clear height-to-thickness (hu/tw) ratios that can exceed 20, and height-to-length (hu/Lw) aspect ratios usually greater than 1.5. Experimental studies have shown that the response of DSRMSWs subjected to in-plane simulated seismic loading is often affected by multiple failure modes. The initial failure mode often transitions into other failure modes that may govern the response of the DSRMSWs at high ductility demand levels. It is essential that designers understand the prominent DSRMSW failure modes and how they interact with one another to ensure the adequate seismic performance of DSRMSWs. Seismic design and detailing provisions for DSRMSWs contained in international design codes aim for a ductile, well-controlled flexure-dominant seismic response and preclude the occurrence of undesirable shear-dominant failure modes. However, the interaction between various failure modes is usually only accounted for implicitly. The capacity predictions for DSRMSWs based on in-plane ductile failure modes vary between different masonry design codes in terms of the methodology, complexity level, and material resistance factors. This paper provides a detailed comparison of the capacity predictions from the following international codes: CSA S304-14 (Canada); TMS 402/602-16 (USA); NZS 4230:2004 (New Zealand); and Eurocodes 6 and 8 – EN 1996-1-1:2005/EN 1998-1:2004 (EU). The assessment focuses on the following six in-plane flexure-dominant failure modes: (i) ductile flexure, (ii) shear-flexure, (iii) sliding, (iv) toe-crushing, (v) rocking/bond-slip, and (vi) lateral instability, observed in a series of eight full-scale, fully-grouted DSRMSW specimens tested under reversed cyclic loading. The specimens were characterized by varying hu/Lw and hu/tw ratios, the amount and distribution of reinforcement, cross-sectional shape, axial stress level, and type of cyclic loading protocol. The results of this study provide a systematic comparison of the DSRMSW capacity predictions from the different international masonry design codes.

This paper presents the results of a multiphase research program aimed at investigating the out-of-plane stability of slender reinforced masonry shear walls (RMSWs) under in-plane reversed-...

In adults with osteoarthritis, clinical pain and disability have been shown to differ across sex and ethnicity/race. Recent evidence also indicates changes in pain-related brain structure across these groups. Resilience is associated with lower pain and greater functioning. However, the relationship between resilience and the brain is not well understood. We investigated if resilience was associated with pain-related brain structure in individuals with/without knee pain and if patterns differed by sex and ethnicity/race. Study participants included 171 individuals (mean age 57.97±8.50; 62 male/109 female; 72 Non-Hispanic Black (NHB)/99 Non-Hispanic White (NHW) with and without knee pain. Participants completed measures of resilience: biobehavioral (tobacco use and waist/hip ratio) and psychosocial (optimism, affect, coping, perceived stress, and social support). Responses were dichotomized based on published norms/means and summed, creating a composite resilience score. High and low resilience was defined by median split. T1-weighted MRI data were processed using FreeSurfer for a priori region analyses. Potential covariates included age, sex, race, study site, education level, body mass index, and chronic pain severity based on the FITT index (frequency, intensity, time/duration, and total pain sites). MANCOVAs were completed for analyses. The high and low resilience groups differed in amygdala volume (p=0.021) with trends for medial prefrontal cortex (MPFC; p=0.064) and thalamus (p=0.094). Males with high resilience had thicker MPFC than low resilience males (p=0.037). Females with high resilience had larger amygdala than low resilience females (p=0.005). NHB with high resilience had larger amygdala (p=0.025) and a trend for thicker somatosensory cortex (p=0.064). NHW with high resilience had a trend for thicker insula (p=0.081). Preliminary findings indicate resilience may be associated with pain-related brain structure. Sex and ethnic/race group differences were also observed. Prospective research is needed to elucidate the influence of resilience on the experience of pain, neurobiological underpinnings, and sex and ethnicity/race differences.

Background: Hemangiosarcoma (HSA) is a common malignancy of dogs with characteristic early, aggressive metastasis. Diagnosis of HSA is challenging because of lack of sensitive and specific diagnostic tests. Hypothesis: Specific proteins that are increased in serum of dogs with HSA might represent useful biomarkers of the disease. Animals: Thirty-four dogs with HSA and 42 healthy dogs from the Ontario Veterinary College Teaching Hospital. Methods: This case-control study compared serum proteins in dogs with HSA and healthy dogs. Proteins were separated by 2-dimensional difference gel electrophoresis and identified by liquid chromatography and tandem mass spectrometry. Results: Western blot analysis showed that serum collagen XXVII peptide concentration in serum of dogs with large metastatic HSA burdens (1,488, 231–3,754 DU; median, minimum-maximum); was, on average, 9.5-fold higher than in healthy dogs (156; 46–2,101 DU). While concentrations for dogs with osteosarcomas (678; 124–3,251 DU), lymphomas (423; 92–2,777 DU), carcinomas (1,022; 177–3,448 DU), and inflammatory disease were also increased, values were consistently lower than those for HSA. Receiver operating characteristic curves revealed an estimated area under the curve of 83% for HSA cases whereas areas for other neoplastic and nonneoplastic diseases were nondiscriminatory. Serum collagen XXVII peptide concentration before splenectomy (1,350; 1,156–1,929 DU) was reduced after tumor removal (529; 452–562 DU) and chemotherapy but increased in 2 dogs with tumor recurrence (511–945 DU; 493–650 DU). Conclusions and Clinical Importance: Collagen XXVII peptide might be useful for diagnosis and monitoring of advanced HSA.

The objective of this epidemiological study was to identify risk factors for Neospora caninum-related abortions in Ontario Holstein dairy herds. A total of 88 herds, consisting of 5080 cattle, and utilizing Dairy Herd Improvement (DHI) services, were divided into three groups. Case (n = 30) and first control (n = 31) herds were selected from 1998 and 1999 fetal abortion submissions to the Animal Health Laboratory, University of Guelph, that were histopathologically positive or negative, respectively, for N. caninum. A second control group (n = 27) was selected from multiple sources of herds sampled within the previous 4 years that had a low seroprevalence (

Background & aims: The SAMP1/Yit mouse strain develops spontaneous ileitis with histologic features of Crohn's disease. Disease expression in the SAMP1/YitFc subline (SAMP1/Fc) is partially inhibited by outcross to C57BL/6J (B6) mice, suggesting complex genetic control of disease susceptibility with both dominant and recessive determinants. We performed a genetic analysis of a (B6 × SAMP1/Fc)F 2 cross to localize the genes regulating intestinal inflammation in this model. Methods: A genome-wide scan was performed using a panel of microsatellite loci determined to be informative for this cross. Quantitative trait loci were identified with Map Manager QT using a serial regression approach. Positional candidate genes were selectively sequenced at the genomic level to identify potential susceptibility genes for functional screening. Results: A genome-wide scan of (B6 × SAMP1/Fc)F 2 mice identified a SAMP-derived quantitative trait loci with additive effects on chromosome 9 in a region likely to have been inherited from the AKR mouse strain. The candidate interval contains several genes of interest because of their potential role in either immune system function, intestinal epithelial function, or both. Suggestive evidence for additional loci was also observed on chromosomes 6 and X. Conclusions: The SAMP1/Fc allele for a locus, designated Ibdq1 , promotes inflammation-associated epithelial damage in these mice. Consistent with persistent mild ileitis in (B6 × SAMP1/Fc)F 1 mice, this locus appears to function in an additive fashion. Two genes in this interval, encoding the interleukin 10 receptor α chain and interleukin 18, are excellent candidates for Ibdq1 .

Among NZB/W-derived New Zealand mixed (NZM) strains, only NZM/Aeg2410 (NZM2410) has been well characterized. In contrast to NZM2410, NZM2328 mice develop autoantibodies and acute and severe chronic glomerulonephritis (GN) with female predominance similarly to NZB/WF1 and humans with systemic lupus erythematosus (SLE). Chronic GN with glomerular sclerosis and tubular atrophy but not acute GN was correlated with severe proteinuria. In a backcross analysis of (NZM2328 X C57L/J) F1 X NZM2328, four SLE susceptibility genomic intervals were identified. One of them (Cgnz1) is on the telomeric end of chromosome 1 and close to Sle1. It was significantly linked to chronic GN. A locus (Agnz1) distinct from Cgnz1 on this interval was suggestively linked to acute GN. Two genetic intervals on chromosome 17 were also suggestively linked to acute GN, one of which is the H-2-Tnf complex, while the other (Agnz2) is on the distal end of the chromosome. A single locus (Adaz1) identified in the midregion of chromosome 4 in NZM2328 mice was suggestively linked to plasma levels of IgG anti-dsDNA autoantibodies. These results differ significantly from those in the backcross analysis of (NZM2410 X C57BL/6)F1 X NZM2410 by other investigators. They support the concept that different sets of genes are involved in acute and chronic GN. The genomic differences between the NZM strains and between C57L/J and C57BL/6 account for the differences between our analysis and that on NZM 2410. These results provide evidence for the importance of background genes on the expression of SLE, with implications for genetic studies of human SLE.

We investigated the thermal properties of several imidazolium salts using DSC and TGA/SDTA data. Many of these salts are liquids at sub-ambient temperatures. These ionic liquids form glasses at low temperatures and have minimal vapor pressure up to their thermal decomposition temperature (>400°C). Thermal decomposition is endothermic with the inorganic anions and exothermic with the organic anions investigated. Halide anions drastically reduce the thermal stability of these salts (

The specific ionic conductivity, dynamic viscosity, and electrochemical stability of several imidazolium salts are reported as neationic liquids and their solutions in several organic solvents. The temperature dependence of conductivity and viscosity are analyzed for 1‐ethyl‐3‐methylimidazolium and 1,2‐dimethyl‐3‐n‐propylimidazolium salts, and the influence of theanions bis(trifluoromethylsulfonyl)imide , bis(perfluoroethylsulfonyl)imide , hexafluoroarsenate , hexafluorophosphate , and tetrafluoroborate on these properties are discussed. These imidazolium salts make possible electrolytes with high concentration (>3 M), high room temperature conductivity (up to 60 mS/cm), and a wide window of stability . Differential scanning calorimetric results confirm a large glass phase for the ionic liquids, with substantial (>80°C) supercooling. Thermal gravimetric results indicate the imidazolium salts with and anions to be thermally more stable than the lithium salt analogs. The Vogel‐Tammann‐Fulcher interpretation accurately describes the conductivity temperature dependence. © 1999 The Electrochemical Society. All rights reserved.

The structure of the title compound, C8H14NO2P, the first of a compound containing a 1,2-buta­dienyl group bound to the phospho­rus of a 1,3,2-ox­aza­phospho­rinane ring, is reported.

Hemangiosarcoma (HSA) is a common malignancy of dogs with characteristic early, aggressive metastasis. Diagnosis of HSA is challenging because of lack of sensitive and specific diagnostic tests.Specific proteins that are increased in serum of dogs with HSA might represent useful biomarkers of the disease.Thirty-four dogs with HSA and 42 healthy dogs from the Ontario Veterinary College Teaching Hospital.This case-control study compared serum proteins in dogs with HSA and healthy dogs. Proteins were separated by 2-dimensional difference gel electrophoresis and identified by liquid chromatography and tandem mass spectrometry.Western blot analysis showed that serum collagen XXVII peptide concentration in serum of dogs with large metastatic HSA burdens (1,488, 231-3,754 DU; median, minimum-maximum); was, on average, 9.5-fold higher than in healthy dogs (156; 46-2,101 DU). While concentrations for dogs with osteosarcomas (678; 124-3,251 DU), lymphomas (423; 92-2,777 DU), carcinomas (1,022; 177-3,448 DU), and inflammatory disease were also increased, values were consistently lower than those for HSA. Receiver operating characteristic curves revealed an estimated area under the curve of 83% for HSA cases whereas areas for other neoplastic and nonneoplastic diseases were nondiscriminatory. Serum collagen XXVII peptide concentration before splenectomy (1,350; 1,156-1,929 DU) was reduced after tumor removal (529; 452-562 DU) and chemotherapy but increased in 2 dogs with tumor recurrence (511-945 DU; 493-650 DU).Collagen XXVII peptide might be useful for diagnosis and monitoring of advanced HSA.

Hexahydropyrimidines N,N-bridged by a chain of n methylene groups (1,(n+2)-diazabicyclo[n.3.1]alkanes) adopt out,out (axial,axial) structures for n=2, 3, and 4. When n=5, the photoelectron spectrum shows evidence of the presence of some of the out, in (axial,equatorial) isomer in the gas phase, although none can be found in solution. When n=6, the compound is apparently entirely out,in in the gas phase but exists as a mixture of out,out and out,in conformers in solution. For n=1, only the diamond lattice out,in isomer can be detected in solution. These experimental data are correlated with force field (MM2) calculations; multiple minimum search methods have been used to locate all low-energy conformations

To investigate the influence of environmental factors on inherited tendencies, the impact of chronic environmental stress on the expression of a genetically determined autoimmune disease was explored in the bio-breeding (BB) rat, which is an animal model for human autoimmune insulin-dependent diabetes mellitus. Animals assigned at random to the experimental group received a triad of stressors designed to model chronic moderate stress over a 14-week period. Animals from 25 to 130 days of age were weighed and tested for glycosuria twice weekly. Weekly blood sampling was performed on all animals. Diabetes was diagnosed on the basis of weight loss, 2+ glycosuria, and blood glucose levels of 250+ mg/dl. We found that in the BB rat chronic stress significantly increased the incidence of the phenotypic expression of the gene for Type I diabetes. Eighty percent of the male stress and 70% of the female stress animals developed diabetes, compared with 50% in both control groups. Stressed males developed manifest diabetes at the same time as their matched controls, whereas stressed females had significantly delayed onset in relation to controls.

Electrolytes based on 1-ethyl-3-methylimidazolium cation (EMI{sup +}) and either the hexafluorophosphate (EMIPF{sub 6}) or tetrafluorborate (EMIBF{sub 4}) anion in organic alkyl carbonate solvents have been evaluated for use in electrochemical capacitors. The conductivity, capacitance, limiting oxidation and reduction potentials, and thermal stability were assessed. High conductivity and capacitance values were found regardless of whether cyclic (high viscosity/high dielectric constant) or acyclic (low viscosity/low dielectric constant) alkyl carbonates were used. The best correlation with conductivity for the EMIPF{sub 6} salt was found to be the molecular weight and to a lesser degree the viscosity of the solvent. The high specific capacitance (130 F/g) and excellent stability (>3.5 V, >130 C) make these electrolytes well suited for use in electrochemical double-layer capacitors.

The emergence of antimicrobial-resistant Salmonella organisms, especially Salmonella Typhimurium DT104, has been reported in many countries, including the United States and Canada. The purposes of this study were to determine the antimicrobial resistance patterns of Salmonella isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in Ontario and to determine the agreement between the agar dilution method and the microbroth dilution method for measurement of antimicrobial resistance of the isolates. Antimicrobial resistance of Salmonella isolates from hogs (n = 71), beef (n = 24), and chicken (n = 295) to amikacin, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, streptomycin, sulfamethoxazole, and tetracycline was determined using the two methods. None of the 390 isolates were resistant to ciprofloxacin at levels of 0.125 microg/ml. All chicken and hog isolates were sensitive to amikacin, whereas all beef isolates were sensitive to both amikacin and gentamicin. Multiple antimicrobial resistance (resistance to more than one antimicrobial) was found in 29% of bovine isolates and 42% of porcine isolates using both methods for testing and in 42% by the agar dilution and 33% by the microbroth dilution methods in the chicken isolates. Overall, there was good agreement between the two test methods for resistance to most of the antimicrobials, with disagreement found in the results in 1.3% of the isolates for ampicillin and sulfamethoxazole, 8.2% for streptomycin, 5.6% for cephalothin, and 1.0% of the isolates for tetracycline. The lack of agreement between the two test methods was found mostly among the chicken isolates.

Publisher Summary This chapter discusses evidence relevant to the brain structures that may be target sites for the effects of vasopressin (VP) and oxytocin (OT) on memory processing and the monoamine classic transmitter systems with which these neuropeptides may interact to produce these effects. Lesion and microinjection techniques have been used to localize the central sites at which VP and OT exert their effects on memory storage and retrieval. Lesioning a structure important to the influence of the peptide on storage or retrieval can attenuate or prohibit the relevant retention behavior on subsequent peptide treatment of the lesioned subjects. Microinjection of a peptide or its antiserum into a specific brain site is justified on the basis that increasing or reducing its level in a brain site that normally mediates the influence of the peptide on retention should enhance and impair retention behavior. The results of the studies described in the chapter indicate that the thalamic prefrontal cortex (PFC) nucleus, part of the diffuse thalamic arousal system, is involved in mediating the effects on avoidance retention produced by both sets of peptides.

Publisher Summary This chapter describes research by De Wied and colleagues on several ways vasopressin (VP) and oxytocin (OT) may act in the brain to influence memory processing. These studies investigated (1) the possibility that VP and OT act as precursors of smaller peptides, oligopeptides, that have memory-processing functions, (2) the nature of the receptor sites that may mediate the memory-modulating effects of VP and OT, (3) the influence of VP on hippocampal theta activity, a putative neural correlate of memory consolidation, during paradoxical sleep (PS), and (4) the neuromodulator functions of VP and OT and their relation to the role of the peptides in memory processing in the septal–hippocampus system. The specific propositions derived from these research studies, together with a restatement of findings specifically relevant to each, are also discussed in the chapter. The neuropeptide concept was formulated by De Wied, as findings indicated the neurogenic effects of pituitary hormones such as adrenocorticotropic hormone (ACTH) and related peptides, and it was periodically expanded and updated with continued neuropeptide research.