Rapid eye movement (REM) sleep is an important component of the natural sleep/wake cycle, yet the mechanisms that regulate REM sleep remain incompletely understood. Cholinergic neurons in the ...mesopontine tegmentum have been implicated in REM sleep regulation, but lesions of this area have had varying effects on REM sleep. Therefore, this study aimed to clarify the role of cholinergic neurons in the pedunculopontine tegmentum (PPT) and laterodorsal tegmentum (LDT) in REM sleep generation. Selective optogenetic activation of cholinergic neurons in the PPT or LDT during non-REM (NREM) sleep increased the number of REM sleep episodes and did not change REM sleep episode duration. Activation of cholinergic neurons in the PPT or LDT during NREM sleep was sufficient to induce REM sleep.
Fidelity between teaching activities and assessment methods is an important goal of knowledge and performance evaluations in medical education. Ideally, assessment methods provide evidence of ...learning that reflects the types of knowledge described in the learning objectives of the course. The most reliable assessments involve the same or similar tasks as those used during the instructional components of the course. Our preclinical human anatomy course includes, in addition to traditional lecture and cadaver‐based laboratory learning activities, a series of applied human anatomy learning activities intended to emphasize human anatomy as it is encountered in living human individuals. The learning activities involve psychomotor behaviors including inspection, palpation, and auscultation, techniques used in the physical examination, as well as other activities designed to emphasize anatomical structures and tissues as they may be found in patient populations. We describe here our method for measuring student success in learning human anatomy in this manner, highlighting the direct linkage between the learning activities and the assessment tasks. We describe our performance scoring method and how we include this data in the calculation of an anatomy examination grade. As an indicator of our success with this approach, we include performance scores for the applied anatomy questions included on the laboratory component of our unit examinations for two successive academic years. We conclude with summary comments from students regarding the applied anatomy learning activities and assessment approach and offer suggestions for addressing specific challenges associated with the use of these types of assessment methods.
The ability to perform and interpret the physical examination requires an understanding of human anatomy and how to apply that content in the clinical setting. Previous work has shown that students ...understand and retain information more effectively when they are actively engaged in the learning process and it is clearly linked to other coursework and their future needs. We developed a series of learning activities, based on the general physical examination, designed to enhance engagement and encourage durable learning of anatomical principles that are important in performing and interpreting the physical examination. Activities were designed for use in small group settings with faculty supervision and input as needed. We describe these activities and provide comments from students regarding the perceived value of these learning activities. Students reported that the applied anatomy learning activities were engaging and aided in their learning of human anatomy. Additionally, students appreciated the connection between the applied anatomy activities and the skills being learned in concurrent coursework focusing on the physical examination. We observed that applied human anatomy exercises modeled after components of the general physical examination and embedded in an anatomy course enhanced student engagement and helped students appreciate the importance of anatomical principles. We note that sensitivity to and acceptance of personal preferences and religious matters must be shown when using learning activities that involve close physical interactions to teach anatomical topics.
Based on density functional theory, we investigate the ferroelectric and piezoelectric properties of the AlN/ScN superlattice, consisting of ScN and AlN buckled monolayers alternating along the ...crystallographic c-direction. We find that the polar wurtzite (w-ScAlN) structure is mechanically and dynamically stable and is more stable than the nonpolar hexagonal flat configuration. We show that ferroelectric polarization switching can be possible for an epitaxially tensile-strained superlattice. Because of the elastic constant C 33 softening, together with an increase in e 33, the piezoelectric coefficient d 33 of the superlattice is doubled compared to that of pure w-AlN. The combined enhancement of Born effective charges (Z 33) and sensitivity of the atomic coordinates to the external strain ( ∂ u 3 ∂ η 3 ) is the origin of the large piezoelectric constant e 33. Moreover, we show that the epitaxial biaxial tensile strain significantly enhances the piezo-response, so that d 33 becomes 7 times larger than that of w-AlN at 4% strain. The tensile strain results in a huge enhancement in e 33 by increasing Z 33 and ∂ u 3 ∂ η 3 , which boost the piezoelectric.
Work on the design of new TiO2 based photocatalysts is described. The key concept is the formation of composite structures through the modification of anatase and rutile TiO2 with molecular‐sized ...nanoclusters of metal oxides. Density functional theory (DFT) level simulations are compared with experimental work synthesizing and characterizing surface modified TiO2. DFT calculations are used to show that nanoclusters of metal oxides such as TiO2, SnO/SnO2, PbO/PbO2, ZnO and CuO are stable when adsorbed at rutile and anatase surfaces, and can lead to a significant red shift in the absorption edge which will induce visible light absorption; this is the first requirement for a useful photocatalyst. The origin of the red shift and the fate of excited electrons and holes are determined. For p‐block metal oxides the oxidation state of Sn and Pb can be used to modify the magnitude of the red shift and its mechanism. Comparisons of recent experimental studies of surface modified TiO2 that validate our DFT simulations are described. These nanocluster‐modified TiO2 structures form the basis of a new class of photocatalysts which will be useful in oxidation reactions and with a correct choice of nanocluster modified can be applied to other reactions.
Modification of the paradigm photocatalyst TiO2 with molecular‐sized metal oxide nanoclusters can impart visible light activity and enhanced oxidation activity. Design of the photocatalysts through density functional theory simulations, together with experiments, allows rational discovery of new visible light active photocatalyst materials.
Community paramedicine is growing in impact and potential Nolan, Michael J., MA; Nolan, Katherine E., BHSc; Sinha, Samir K., MD DPhil
CMAJ. Canadian Medical Association journal,
05/2018, Letnik:
190, Številka:
21
Journal Article
Recenzirano
Odprti dostop
Increasingly, paramedics are being recognized as uniquely positioned to support sustainable and high-quality health care delivery to Canada's aging population. In some Canadian jurisdictions, ...unnecessary 911 calls and emergency department visits have been rising by as much as 8% annually. Because paramedics initiate care for people in their own homes and communities, these health care professionals are well placed to recognize the unmet needs of the community-dwelling individuals they serve and to act proactively to support efforts to stem unnecessary use of emergency medical services. Research around this novel and rapidly evolving area of practice, however, remains limited. Two recent systematic reviews identified only 11 studies that evaluated community paramedicine and concluded that, although these programs appeared promising, further research about their effectiveness was needed. In linked research, Agarwal and colleagues describe a cluster randomized trial of a preventive wellness clinic-based model of community paramedicine within social-housing buildings. 6
The different oxidation states of chromium allow its bulk oxide form to be reducible, facilitating the oxygen vacancy formation process, which is a key property in applications such as catalysis. ...Similar to other useful oxides such as TiO2, and CeO2, the effect of substitutional metal dopants in bulk Cr2O3 and its effect on the electronic structure and oxygen vacancy formation are of interest, particularly in enhancing the latter. In this paper, density functional theory (DFT) calculations with a Hubbard + U correction (DFT+U) applied to the Cr 3d and O 2p states, are carried out on pure and metal-doped bulk Cr2O3 to examine the effect of doping on the electronic and geometric structure. The role of dopants in enhancing the reducibility of Cr2O3 is examined to promote oxygen vacancy formation. The dopants are Mg, Cu, Ni, and Zn, which have a formal +2 oxidation state in their bulk oxides. Given this difference in host and dopant oxidation states, we show that to predict the correct ground state two metal dopants charge compensated with an oxygen vacancy are required. The second oxygen atom removed is termed “the active” oxygen vacancy and it is the energy required to remove this atom that is related to the reduction process. In all cases, we find that substitutional doping improves the oxygen vacancy formation of bulk Cr2O3 by lowering the energy cost.
Low molecular weight gels are formed by the self-assembly of a suitable small molecule gelator into a three-dimensional network of fibrous structures. The gel properties are determined by the fiber ...structures, the number and type of cross-links and the distribution of the fibers and cross-links in space. Probing these structures and cross-links is difficult. Many reports rely on microscopy of dried gels (xerogels), where the solvent is removed prior to imaging. The assumption is made that this has little effect on the structures, but it is not clear that this assumption is always (or ever) valid. Here, we use small angle neutron scattering (SANS) to probe low molecular weight hydrogels formed by the self-assembly of dipeptides. We compare scattering data for wet and dried gels, as well as following the drying process. We show that the assumption that drying does not affect the network is not always correct.
•We determined the shape of Bennu from radar and lightcurve observations.•We used the Arecibo and Goldstone radars to select a spacecraft mission target.•Combining radar and lightcurve data makes ...shape modeling simpler and more robust.•Asteroid Bennu has a smoother surface than most spacecraft-visited asteroids.•Bennu has a shape similar to binary near-Earth asteroids.
We determine the three-dimensional shape of near-Earth Asteroid (101955) Bennu based on radar images and optical lightcurves. Bennu was observed both in 1999 at its discovery apparition, and in 2005 using the 12.6-cm radar at the Arecibo Observatory and the 3.5-cm radar at the Goldstone tracking station. Data obtained in both apparitions were used to construct a shape model of this object. Observations were also obtained at many other wavelengths to characterize this object, some of which were used to further constrain the shape modeling. The lightcurve data, along with an initial determination of the rotation period derived from them, simplified and improved the shape modeling.
Below we briefly describe the observations and shape modeling process. We discuss the shape model and the implications for the possible formation and evolution of this object. We also describe the importance and limitations of the shape model in view of the fact that this object is the target of the OSIRIS-REx spacecraft mission.
Stereotactic radiotherapy (SRT) involves the precise delivery of highly conformal, dose-intense radiation to well-demarcated tumors. Special equipment and expertise are needed, and a unique ...biological mechanism distinguishes SRT from other forms of external beam radiotherapy. Families find the convenient schedules and minimal acute toxicity of SRT appealing. Common indications in veterinary oncology include nasal, brain, and bone tumors. Many other solid tumors can also be treated, including spinal, oral, lung, heart-base, liver, adrenal, and prostatic malignancies. Accessibility of SRT is improving, and new data are constantly emerging to define parameters for appropriate case selection, radiation dose prescription, and long-term follow-up.
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