954 research outputs found
Assessing professional skills in engineering education
This paper addresses the issue of developing and assessing professional skills in higher education programs. This includes defining and assessing these skills, in the contexts of an individual course unit and for an entire degree program. Identifying forms of assessment that are seen as authentic, meaningful and understandable by the students, teaching staff and curriculum developers are of utmost importance if professional skills are to be accepted and included in the formal curriculum. This can be particularly important in programs that aim to offer students a truly collaborative learning experience in a culturally diverse team. Reflections are presented as one example of an assessment method that fits this requirement. Building assessment based on the notion of threshold concepts is introduced in the context of an open ended group project course unit at Uppsala University
Supervillin Is a Component of the Hair Cell\u27s Cuticular Plate and the Head Plates of Organ of Corti Supporting Cells
The organ of Corti has evolved a panoply of cells with extraordinary morphological specializations to harness, direct, and transduce mechanical energy into electrical signals. Among the cells with prominent apical specializations are hair cells and nearby supporting cells. At the apical surface of each hair cell is a mechanosensitive hair bundle of filamentous actin (F-actin)-based stereocilia, which insert rootlets into the F-actin meshwork of the underlying cuticular plate, a rigid organelle considered to hold the stereocilia in place. Little is known about the protein composition and development of the cuticular plate or the apicolateral specializations of organ of Corti supporting cells. We show that supervillin, an F-actin cross-linking protein, localizes to cuticular plates in hair cells of the mouse cochlea and vestibule and zebrafish sensory epithelia. Moreover, supervillin localizes near the apicolateral margins within the head plates of Deiters\u27 cells and outer pillar cells, and proximal to the apicolateral margins of inner phalangeal cells, adjacent to the junctions with neighboring hair cells. Overall, supervillin localization suggests this protein may shape the surface structure of the organ of Corti
Fascin 2b Is a Component of Stereocilia that Lengthens Actin-Based Protrusions
Stereocilia are actin-filled protrusions that permit mechanotransduction in the
internal ear. To identify proteins that organize the cytoskeleton of
stereocilia, we scrutinized the hair-cell transcriptome of zebrafish. One
promising candidate encodes fascin 2b, a filamentous actin-bundling protein
found in retinal photoreceptors. Immunolabeling of zebrafish hair cells and the
use of transgenic zebrafish that expressed fascin 2b fused to green fluorescent
protein demonstrated that fascin 2b localized to stereocilia specifically. When
filamentous actin and recombinant fusion protein containing fascin 2b were
combined in vitro to determine their dissociation constant, a
Kd≈0.37 µM was observed. Electron
microscopy showed that fascin 2b-actin filament complexes formed parallel actin
bundles in vitro. We demonstrated that expression of fascin 2b
or espin, another actin-bundling protein, in COS-7 cells induced the formation
of long filopodia. Coexpression showed synergism between these proteins through
the formation of extra-long protrusions. Using phosphomutant fascin 2b proteins,
which mimicked either a phosphorylated or a nonphosphorylated state, in COS-7
cells and in transgenic hair cells, we showed that both formation of long
filopodia and localization of fascin 2b to stereocilia were dependent on serine
38. Overexpression of wild-type fascin 2b in hair cells was correlated with
increased stereociliary length relative to controls. These findings indicate
that fascin 2b plays a key role in shaping stereocilia
Zebrafish TRPA1 Channels Are Required for Chemosensation But Not for Thermosensation or Mechanosensory Hair Cell Function
Transient receptor potential (TRP) ion channels have been implicated in detecting chemical, thermal, and mechanical stimuli in organisms ranging from mammals to Caenorhabditis elegans. It is well established that TRPA1 detects and mediates behavioral responses to chemical irritants. However, the role of TRPA1 in detecting thermal and mechanical stimuli is controversial. To further clarify the functions of TRPA1 channels in vertebrates, we analyzed their roles in zebrafish. The two zebrafish TRPA1 paralogs are expressed in sensory neurons and are activated by several chemical irritants in vitro. High-throughput behavioral analyses of trpa1a and trpa1b mutant larvae indicate that TRPA1b is necessary for behavioral responses to these chemical irritants. However, TRPA1 paralogs are not required for behavioral responses to temperature changes or for mechanosensory hair cell function in the inner ear or lateral line. These results support a role for zebrafish TRPA1 in chemical but not thermal or mechanical sensing, and establish a high-throughput system to identify genes and small molecules that modulate chemosensation, thermosensation, and mechanosensation
A face for all seasons:searching for context-specific leadership traits and discovering a general preference for perceived health
Previous research indicates that followers tend to contingently match particular leader qualities to evolutionarily consistent situations requiring collective action (i.e., context-specific cognitive leadership prototypes) and information processing undergoes categorization which ranks certain qualities as first-order context-general and others as second-order context-specific. To further investigate this contingent categorization phenomenon we examined the “attractiveness halo”—a first-order facial cue which significantly biases leadership preferences. While controlling for facial attractiveness, we independently manipulated the underlying facial cues of health and intelligence and then primed participants with four distinct organizational dynamics requiring leadership (i.e., competition vs. cooperation between groups and exploratory change vs. stable exploitation). It was expected that the differing requirements of the four dynamics would contingently select for relatively healthier- or intelligent-looking leaders. We found perceived facial intelligence to be a second-order context-specific trait—for instance, in times requiring a leader to address between-group cooperation—whereas perceived health is significantly preferred across all contexts (i.e., a first-order trait). The results also indicate that facial health positively affects perceived masculinity while facial intelligence negatively affects perceived masculinity, which may partially explain leader choice in some of the environmental contexts. The limitations and a number of implications regarding leadership biases are discussed
Metered Cryospray™: a novel uniform, controlled, and consistent in vivo application of liquid nitrogen cryogenic spray
Typically, wood-based composite materials have been developed through empirical studies. In these products, the constituent wood elements have broad spectrums regarding species, size, and anatomical orientation relative to their own dimensions. To define special strength and stiffness properties during a long-term study, two types of corrugated wood composite panels were developed for possible structural utilization. The constitutional elements of the newly developed products included Appalachian hardwood veneer residues (side clippings) and/or rejected low quality, sliced veneer sheets. The proposed primary usage of these veneer-based panels is in applications where the edgewise loading may cause buckling (e.g., web elements of I-joists, shear-wall and composite beam core materials). This paper describes the development of flat and corrugated panels, including furnish preparations and laboratory-scale manufacturing processes as well as the determination of key mechanical properties. According to the results in parallel to grain direction bending, tension and compression strengths exceeded other structural panels’ similar characteristics, while the rigidities were comparable. Based on the research findings, sliced veneer clipping waste can be transformed into structural panels or used as reinforcement elements in beams and sandwich-type products
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Concise total syntheses of (–)-jorunnamycin A and (–)-jorumycin enabled by asymmetric catalysis
The bis-tetrahydroisoquinoline (bis-THIQ) natural products have been studied intensively over the past four decades for their exceptionally potent anticancer activity, in addition to strong gram-positive and -negative antibiotic character. Synthetic strategies toward these complex polycyclic compounds have relied heavily on electrophilic aromatic chemistry, such as the Pictet-Spengler reaction, that mimics their biosynthetic pathways. Herein we report an approach to two bis-THIQ natural products, jorunnamycin A and jorumycin, that instead harnesses the power of modern transition-metal catalysis for the three major bond-forming events and proceeds with high efficiency (15 and 16 steps, respectively). By breaking from biomimicry, this strategy allows for the preparation of a more diverse set of non-natural analogs
Damage costs from invasive species exceed management expenditure in nations experiencing lower economic activity
Financial disclosure The InvaCost project was funded by the French National Research Agency (ANR-14-CE02-0021), the BNP-Paribas Foundation Climate Initiative, the AXA Research Fund Chair of Invasion Biology of University Paris Saclay and by the BiodivERsA and Belmont-Forum call 2018 on biodiversity scenarios (AlienScenarios; BMBF/PT DLR 01LC1807C). M.K. received funding from the European Union's Horizon 2020 research programme under a Marie Skłodowska-Curie grant agreement 899546. C.J.A.B. acknowledges the Australian Research Council (CE170100015) for support. A.B. acknowledges Azim Premji University's grants programme (UNIV-RC00326) for support.Peer reviewe
Investigating the Potential and Pitfalls of EV-Encapsulated MicroRNAs as Circulating Biomarkers of Breast Cancer
Extracellular vesicles (EVs) shuttle microRNA (miRNA) throughout the circulation and are believed to represent a fingerprint of the releasing cell. We isolated and characterized serum EVs of breast tumour-bearing animals, breast cancer (BC) patients, and healthy controls. EVs were characterized using transmission electron microscopy (TEM), protein quantification, western blotting, and nanoparticle tracking analysis (NTA). Absolute quantitative (AQ)-PCR was employed to analyse EV-miR-451a expression. Isolated EVs had the appropriate morphology and size. Patient sera contained significantly more EVs than did healthy controls. In tumour-bearing animals, a correlation between serum EV number and tumour burden was observed. There was no significant relationship between EV protein yield and EV quantity determined by NTA, highlighting the requirement for direct quantification. Using AQ-PCR to relate miRNA copy number to EV yield, a significant increase in miRNA-451a copies/EV was detected in BC patient sera, suggesting potential as a novel biomarker of breast cancer
Solution structure of a repeated unit of the ABA-1 nematode polyprotein allergen of ascaris reveals a novel fold and two discrete lipid-binding sites
Parasitic nematode worms cause serious health problems in humans and other animals. They can induce allergic-type immune responses, which can be harmful but may at the same time protect against the infections. Allergens are proteins that trigger allergic reactions and these parasites produce a type that is confined to nematodes, the nematode polyprotein allergens (NPAs). These are synthesized as large precursor proteins comprising repeating units of similar amino acid sequence that are subsequently cleaved into multiple copies of the allergen protein. NPAs bind small lipids such as fatty acids and retinol (Vitamin A) and probably transport these sensitive and insoluble compounds between the tissues of the worms. Nematodes cannot synthesize these lipids, so NPAs may also be crucial for extracting nutrients from their hosts. They may also be involved in altering immune responses by controlling the lipids by which the immune and inflammatory cells communicate. We describe the molecular structure of one unit of an NPA, the well-known ABA-1 allergen of Ascaris and find its structure to be of a type not previously found for lipid-binding proteins, and we describe the unusual sites where lipids bind within this structur
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