361 research outputs found
Planothidium quarnerensis fm. rhombica Witkowski & Riaux-Gobin
No full text33. Planothidium quarnerensis f. rhombica (Giffen) Witkowski & Riaux-Gobin (Figs 89, 90) Basionym: Cocconeis quarnerensis f. rhombica Giffen. Type locality: Mahé Island, Seychelles. Reference: Riaux-Gobin et al. 2018, p. 117, figs 45–48. Morphomerics: Valves 13–24 (15–18) μm long, 7–11 (10–11) μm wide, transapical striae 10–11 (8–9) in 10 μm of sternum valve, 11–12 (9) in 10 μm of raphe valve. Remarks: The structure of vestigial striae is distinct in the axial area of sternum valve. Local specimens are slightly longer, but narrower in width, compared with the type ones. This taxon was reported only from the type locality, Mahé Island of the Seychelles, and probably tropical taxon in warmer coasts. It was rare epiphytes on seaweeds along the Seogwipo coast in Jeju Island, and this is a new report to South Korea.Published as part of Joh, Gyeongje, 2021, Distribution and frequent occurrence of diatom taxa (Bacillariophyta) inhabiting warmer oceans in Seogwipo coast of Jeju Island, southernmost Korea, pp. 1-67 in Phytotaxa 517 (1) on page 25, DOI: 10.11646/phytotaxa.517.1.1, http://zenodo.org/record/806105
Histamine treatment induces rearrangements of orthogonal arrays of particles (OAPs) in human AQP4-expressing gastric cells
No full textTo test the involvement of the water channel aquaporin (AQP)-4 in gastric acid physiology, the human gastric cell line (HGT)-1 was stably transfected with rat AQP4. AQP4 was immunolocalized to the basolateral membrane of transfected HGT-1 cells, like in native parietal cells. Expression of AQP4 in transfected cells increased the osmotic water permeability coefficient (P-f) from 2.02 +/- 0.3 x 10(-4) to 16.37 +/- 0.5 x 10(-4) cm/s at 20 degreesC. Freeze-fracture EM showed distinct orthogonal arrays of particles (OAPs), the morphological signature of AQP4, on the plasma membrane of AQP4-expressing cells. Quantitative morphometry showed that the density of OAPs was 2.5 +/- 0.3% under basal condition and decreased by 50% to 1.2 +/- 0.3% after 20 min of histamine stimulation, mainly due to a significant decrease of the OAPs number. Concomitantly, P-f decreased by similar to 35% in 20-min histamine-stimulated cells. Both P-f and OAPs density were not modified after 10 min of histamine exposure, time at which the maximal hormonal response is observed. Cell surface biotinylation experiments confirmed that AQP4 is internalized after 20 min of histamine exposure, which may account for the downregulation of water transport. This is the first evidence for short term rearrangement of OAPs in an established AQP4-expressing cell line
Metastatic deaths in retinoblastoma patients treated with intraarterial chemotherapy (ophthalmic artery chemosurgery) worldwide
No full textAbstract Background Ophthalmic artery chemosurgery [OAC, intra-arterial chemotherapy (IAC)] was introduced in 2006 as treatment modality for intraocular retinoblastoma. The purpose of this commentary is to retrospectively review the incidence of metastatic deaths in retinoblastoma patients treated with OAC worldwide over a 10 year period. Retrospective data regarding metastatic deaths was collected from six international retinoblastoma centers (New York City USA, Philadelphia USA, Sao Paulo Brazil, Siena Italy, Lausanne Switzerland and Buenos Aires Argentina). All retinoblastoma patients from these centers (naive and recurrent, unilateral and bilateral) treated with OAC/IAC since 2006 have been included in this study. Data regarding number of patients, number of OAC/IAC infusions, number unilateral and bilateral, number treated for naive disease or salvage and number of metastatic deaths have been assessed. Over a 10-year period of time 1139 patients received OAC/IAC for 4396 infusions. At last follow-up there were only three metastatic deaths (all treated in Buenos Aires). Conclusion The current survey assessed the recorded risk of metastatic deaths in six retinoblastoma centers worldwide in children with retinoblastoma (unilateral or bilateral) treated with OAC/IAC as primary or secondary therapy. Overall, the observed risk for metastatic deaths from retinoblastoma was <1% in OAC/IAC treated children
Long-term soil erosion plot data to evaluate the PESERA (Pan European Soil Erosion Risk Assessment) approach
No full text
ÉTUDE DU MOUVEMENT DES DISLOCATIONS DANS L'ALUMINIUM PAR MESURE DE L'ATTÉNUATION ET DE LA VITESSE DES ONDES ULTRASONORES
No full textNous avons réalisé un nouvel ensemble de mesures ultrasonores opérant dans le domaine du bas mégahertz et associé à une machine de traction. Cet ensemble nous a permis de suivre les variations Ɗα de l'atténuation et Ɗ( Ɗν/ν) de l'anomalie de vitesse dans un aluminium 99,999 % pendant l'application d'une contrainte σ croissante. Les courbes expérimentales Ɗα, Ɗ(Ɗν/ν) = f(σ) permettent d'étudier de façon sélective d'une part le désancrage des dislocations à partir de défauts ponctuels, d'autre part la multiplication des défauts linéaires. En développant un modèle simple présenté dans un travail précédent, nous avons déterminé certaines caractéristiques des dislocations mobiles après une déformation plastique et un vieillissement effectués dans diverses conditions. En particulier, nous avons pu montrer que pour mesurer la densité de défauts linéaires, il est, dans certains cas, nécessaire de tenir compte des interactions entre dislocations et défauts ponctuels.A new device for measurements of changes Ɗα in ultrasonic attenuation together with changes Ɗ( Ɗν/ν) in ultrasonic velocity made concurrently with tensile tests on the same specimen of 99.999 % aluminium, is presented. Unpinning of dislocation from point defect on one hand, multiplication of linear defects on the other hand are separately studied from the experimental curves Ɗα, Ɗ( Ɗν/ν) = f(σ). Some data concerning mobile dislocations obtained by various plastic deformation and subsequent ageing have been computed with the help of a simple model presented in an earlier paper. So, it appears that dislocation density measurements are, for some cases, to be made taking into account interaction between dislocations and point defects
Smart materials and structures : facts or dream ?
No full textThe multifunctional, heterogeneous or composite materials combine, given this heterogeneity, properties which appeal- to be contradictory such as high mechanical stength, low density, chemical innocuousness and relative toughness...This trend toward controlled complexity, to a “custom-designed” synthesised material system, was able to provide an quasi-exact answer to the requirements of the designer, but is nowadays no longer considered to be sufficient, and is not achieved in any case.In fact, the requirements set out by the user and formulated by the designer are “mean” requirements which correspond to standard conditions of use.It is therefore clear that the barrier to be crossed henceforth is that to the “adaptive” material, which is capable of adjusting its behavioural law relative to external influences, and in real time if possible. This adjustment assumes an intake of information from the environment and/or the material itself, subsequent processing of this data to produce a suitable response, and finally implementation of the response.The analogy with living organisms is obvious, and it was this which led, during the 1 980's, to the notion of “intelligent” materials.Though the appelation “smart materials” is employed quite widely, it is evident that this term does not have the same significance for everyone.In western countries, the term “intelligent materials” is used mainly to refer to intelligent structures which are formed by the assembly of macroscopically distinct materials, such as a variety of sensors for data-acquisition, microprocessors to process these data, and actuators for implementing the response.The “material” notion appears again if the components are incorporated into a composite material, and if the sensor and actuator functions are no longer separate but rather distribued, as is the case where optical fibre sensors are employed and shape-memory alloys or piezo-electric materials are used as actuators.In this type of “materials system”, intelligent functions are created by the assembly of components on the mesoscopic scale (tens of um to hundreds of um), but it is possible to imagine a true material where the sensor and actuator functions exist on the microstructure scale (a few um 10 4 to a few um).From a rapid analysis, it can be seen that the innovative aspect of the concept of intelligent materials concerns essentially the combination of primitive functions, aimed at endowing the material with a semi-biological behaviour.This approach fits well into the current logic of the multiple-function “customised” material, but an additional threshold has been crossed, where the question no longer concerns the addition of primitive functions, but rather their combination in order to achieve a more elaborate function which can be described as “quasi-intelligence”, that is one which ensures the survival or the optimum use of the material and the system
TRANSFORMATION DE PHASE ET INTERFACESCHANGEMENTS D'ÉTAT ET PROPRIÉTÉS ANÉLASTIQUES DES SOLIDES MÉTALLIQUES
No full textLes transformations à l'état solide sont souvent complexes
et la somme de travaux effectués dans ce domaine est considérable. Cependant la
mesure des propriétés anélastiques a été relativement peu utilisée et le plus
souvent comme simple moyen de mise en évidence du phénomène. La raison
principale paraît en être la grande difficulté d'interprétation des résultats
obtenus. Il est donc nécessaire de relier les manifestations anélastiques aux
mécanismes permettant la transition. Dans ces conditions l'étude des
caractéristiques anélastiques pourra devenir une technique d'analyse des
transformations à l'état solide d'autant plus puissante qu'elle peut souvent
être utilisée pendant le changement d'état lui-même. Après un rappel rapide sur
la nature et le classement des transformations l'auteur passe en revue les
principaux résultats expérimentaux obtenus, dans le cas des transformations du
premier ordre (transformations polymorphiques des métaux purs et des alliages
réalisées par diffusion ; transformation martensitique ; transformation
ordre-désordre) et du second ordre (ordre-désordre-transformations
magnétiques...). Dans une deuxième partie l'auteur signale et compare les
modèles permettant une interprétation ; l'accent est essentiellement mis sur
les transformations hétérogènes.Solid state transformations are generally complex and there
is a considerable amount of work done on this subject. However anelastic
measurements in that field are few, and when used, are merely a mean of
observation of the phenomena because the interpretation of results seems to be
difficult. It is necessary to relate the anelastic changes to the mechanism
involved in transition. The study of the anelastic properties would then be a
technique to analyse solid state transformations ; the usefulness of that
technique being that very often it can be used during the transformation
itself. After a look at the different types of transformations and their
classification, principal experimental results are reviewed for the first and
second order transformations. Models leading to an interpretation are given and
discussed in the second part, mainly for heterogeneous
transformations
A university-specific training program to increase faculty and staff knowledge, comfort, and skills to address student mental health: An instrumental mixed-methods case study
No full textFor over a decade, U.S. universities and colleges have faced a student mental health crisis, exacerbated by the recent COVID-19 pandemic (Copeland et al., 2021; Fu & Cheng, 2017; Lipson et al., 2022; Sapadin & Hollander, 2021; Scofield & Locke, 2022; Xiao et al., 2017; Zhai & Du, 2020). As a result, college counseling centers have struggled to meet the demand for intervention (Arnett, 2000; Auerbach et al., 2018; Ebert et al., 2019; Kraft, 2011; Landberg et al., 2019; Xiao et al., 2017). A recent approach entails universities recruiting non-mental health faculty and staff to help share the responsibility of student mental health care by teaching them basic mental health intervention (Carpini et al., 2020; Cimini et al., 2014; Halladay et al., 2022; Reiff et al., 2019). Minimal research exists, however, on such programs’ effectiveness. This mixed-methods, instrumental case study contributes to examining this burgeoning higher education trend by focusing on one program designed to increase participants’ knowledge, comfort and skills related to student mental health, the Faculty and Staff Mental Health Ambassador Program (FSMHAP). Quantitative pre-training and post-training surveys were designed to capture participants' demographic information and subjective perceptions of their knowledge, comfort, and skills before and after the program. Using quantitative data from 49 participants, Wilcoxon signed rank tests showed significant increases in three areas after the training: comfort supporting students (Z = 4.2, p < .001, r = .60), comfort making referrals to campus resources (Z = 4.3, p< .001, r = .62), and skills to address student mental health (Z = 2.9, p = .003, r = .42). While there was an increase in average student mental health knowledge, this change was insignificant (Z = 1.5, p = 0.16, r = 0.22). Multiple linear regressions were used to test if changes in post-training scores were predicted by demographic variables after controlling for baseline scores. Regressions revealed that post-training knowledge was marginally predicted by being a staff member (R² = .172, F(df) = 5.868 (2, 45), β = 5.16, p < .001***), by older age (R² = .192, F(df) = 6.346 (2, 43), β = 4.02, p = .043*), and identifying as a cisgender woman (R² = .237, F(df) = 3.429 (6, 41), β = 0.98, p = .033*). Post-training comfort level with supporting students’ mental health concerns was marginally but significantly predicted by being a staff member (R² = .346, F(df) = 313.15 (2, 44), β = 0.320, p = .054*) and post-training comfort level with referring students to campus resources was significantly predicted by identifying as bisexual (R² = .295, F(df) = 3.804 (7, 40), β = -0.863, p = .003**). Regressions for predicting post-training for skills related to student mental health were not significant for any demographic variables. Qualitative data from 115 participants were collected throughout the program using responses to training module reflection questions. Eight major themes were identified including (1) Mental Health Topics, (2) Diversity Considerations, (3) Faculty and Staff Reflections, (4) Faculty and Staff Challenges, (5) Faculty and Staff Strategies, (6) Participants’ Positive Experiences of the Training, (7) Suggestions for Program Improvement, and (8) Participants’ Perceptions of Their Needs to be Effective Ambassadors. Overall findings from qualitative data revealed that participants valued practical mental health knowledge (e.g., recognizing signs of distress, choosing interventions) and reported increases in comfort and skills related to addressing student mental health. Thematic suggestions for program improvement included incorporating more interactive simulations to practice intervening with students, having examples that model warm and empathetic language, providing more information on resources for students with marginalized identities, and having options for more advanced training. Overall, participants expressed their desires to be more observant of students, have more patience, and increase their cultural awareness to promote student well-being. Quantitative and qualitative results from this study support prior findings in the literature and indicate training programs like the FSMHAP may be an important area of investment for universities concerned with the student mental health crisis.Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-02-04 without embargo termsThe student, Kathryn Rhoades, accepted the attached license on 2024-04-07 at 07:48.The student, Kathryn Rhoades, submitted this Dissertation for approval on 2024-04-07 at 07:56.This Dissertation was approved for publication on 2024-04-17 at 13:55.DSpace SAF Submission Ingestion Package generated from Vireo submission #20319 on 2025-02-04 at 21:03:1
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