43 research outputs found

    Mass transfer with chemical reaction in gas liquid cocurrent vertical flow.

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    Dept. of Chemistry and Biochemistry. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1973 .D62. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.Sc.)--University of Windsor (Canada), 1973

    Mindfulness Correlates with Stress and Coping in University Students

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    Mindfulness has received significant attention in the empirical literature during the past decade, but few studies have focused on mindfulness in university students and how it may influence problematic behaviours. This study examined the relationships among mindfulness, coping, and physiological reactivity in a sample of university students. Participants completed questionnaires, and skin conductance measurements were collected during an interview where they recalled a personally stressful event. Correlation analyses tested relationships among these variables. There was a negative correlation between substance use and mindfulness. Specifically, those using substances as a coping mechanism were less likely to be mindful and displayed higher physiological reactivity. More mindful individuals were less likely to report misusing substances and were able to calm themselves more quickly than their counterparts following a stressful event. Thus, poor outcomes for distressed students may be reduced with mindfulness-based interventions.  Au cours des dernières dĂ©cennies, la pleine conscience a Ă©tĂ© l’objet d’une attention importante dans la documentation empirique, mais peu d’études ont ciblĂ© la pleine conscience chez les Ă©tudiants et sa façon d’influencer les comportements problĂ©matiques. Cette Ă©tude a Ă©tudiĂ© l’association entre la pleine conscience, les mĂ©canismes d’adaptation et la rĂ©activitĂ© physiologique chez un Ă©chantillon d’étudiants. En plus de rĂ©pondre Ă  des questionnaires, les participants ont dĂ» passer une entrevue oĂą il leur fallait raconter un souvenir personnel particulièrement stressant pendant qu’on mesurait leur conductance cutanĂ©e. Des analyses de corrĂ©lation ont Ă©valuĂ© les liens entre ces variables. Ainsi, on a dĂ©notĂ© une corrĂ©lation nĂ©gative entre l’utilisation de substances nocives et la pleine conscience. Plus prĂ©cisĂ©ment, les participants qui avaient consommĂ© des substances nocives comme mĂ©canisme d’adaptation avaient moins tendance Ă  possĂ©der des traits conscients, et ont dĂ©montrĂ© une rĂ©activitĂ© physiologique plus Ă©levĂ©e que les autres Ă©tudiants. Les gens plus pleinement conscients avaient moins tendance Ă  utiliser des substances nocives, et Ă©taient capables de se calmer plus rapidement que leurs pairs après un Ă©vĂ©nement stressant. Par consĂ©quent, des interventions basĂ©es sur la pleine conscience pourraient aider les Ă©tudiants stressĂ©s Ă  ne pas adopter de comportements problĂ©matiques

    Inherited photoreceptor degeneration causes the death of melanopsin-positive retinal ganglion cells and increases their coexpression of brn3a

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    Purpose: To study the population of intrinsically photosensitive retinal ganglion cells (melanopsin-expressing RGCs, m+RGCs) in P23H-1 rats, a rat model of inherited photoreceptor degeneration. Methods: At postnatal (P) times P30, P365, and P540, retinas from P23H dystrophic rats (line 1, rapid degeneration; and line 3, slow degeneration) and Sprague Dawley (SD) rats (control) were dissected as whole-mounts and immunodetected for melanopsin and/or Brn3a. The dendritic arborization of m+RGCs and the numbers of Brn3a+RGCs and m+RGCs were quantified and their retinal distribution and coexpression analyzed. Results: In SD rats, aging did not affect the population of Brn3a+RGCs or m+RGCs or the percentage that showed coexpression (0.27%). Young P23H-1 rats had a significantly lower number of Brn3a+RGCs and showed a further decline with age. The population of m+RGCs in young P23H-1 rats was similar to that found in SD rats and decreased by 22.6% and 28.2% at P365 and P540, respectively, similarly to the decrease of the Brn3a+RGCs. At these ages the m+RGCs showed a decrease of their dendritic arborization parameters, which was similar in both the P23H-1 and P23H-3 lines. The percentage of coexpression of Brn3a was, however, already significantly higher at P30 (3.31%) and increased significantly with age (10.65% at P540). Conclusions: Inherited photoreceptor degeneration was followed by secondary loss of Brn3a+RGCs and m+RGCs. Surviving m+RGCs showed decreased dendritic arborization parameters and increased coexpression of Brn3a and melanopsin, phenotypic and molecular changes that may represent an effort to resist degeneration and/or preferential survival of m+RGCs capable of synthesizing Brn3a

    Tracing the retina to analyze the integrity and phagocytic capacity of the retinal pigment epithelium

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    We have developed a new technique to study the integrity, morphology and functionality of the retinal neurons and the retinal pigment epithelium (RPE). Young and old control albino (Sprague-Dawley) and pigmented (Piebald Virol Glaxo) rats, and dystrophic albino (P23H-1) and pigmented (Royal College of Surgeons) rats received a single intravitreal injection of 3% Fluorogold (FG) and their retinas were analyzed from 5 minutes to 30 days later. Retinas were imaged in vivo with SD-OCT and ex vivo in flat-mounts and in cross-sections. Fifteen minutes and 24 hours after intravitreal administration of FG retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer reached the RPE 15 minutes after FG administration, and this labeling remained up to 30 days. Tracing for 15 minutes or 24 hours did not cause oxidative stress. Intraretinal tracing delineated the pathological retinal remodelling occurring in the dystrophic strains. The RPE of the P23H-1 strain was highly altered in aged animals, while the RPE of the RCS strain, which is unable to phagocytose, did not accumulate the tracer even at young ages when the retinal neural circuit is still preserved. In both dystrophic strains, the RPE cells were pleomorphic and polymegathic

    Tracing the retina to analyze the integrity and phagocytic capacity of the retinal pigment epithelium

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    We have developed a new technique to study the integrity, morphology and functionality of the retinal neurons and the retinal pigment epithelium (RPE). Young and old control albino (Sprague-Dawley) and pigmented (Piebald Virol Glaxo) rats, and dystrophic albino (P23H-1) and pigmented (Royal College of Surgeons) rats received a single intravitreal injection of 3% Fluorogold (FG) and their retinas were analyzed from 5 minutes to 30 days later. Retinas were imaged in vivo with SD-OCT and ex vivo in flat-mounts and in cross-sections. Fifteen minutes and 24 hours after intravitreal administration of FG retinal neurons and the RPE, but no glial cells, were labeled with FG-filled vesicles. The tracer reached the RPE 15 minutes after FG administration, and this labeling remained up to 30 days. Tracing for 15 minutes or 24 hours did not cause oxidative stress. Intraretinal tracing delineated the pathological retinal remodelling occurring in the dystrophic strains. The RPE of the P23H-1 strain was highly altered in aged animals, while the RPE of the RCS strain, which is unable to phagocytose, did not accumulate the tracer even at young ages when the retinal neural circuit is still preserved. In both dystrophic strains, the RPE cells were pleomorphic and polymegathic.This study was supported by the Spanish Ministry of Economy and Competitiveness, Instituto de Salud Carlos III, Fondo Europeo de Desarrollo Regional “Una manera de hacer Europa” (PI16/00031, PI16/00380, PI19/00071, PI19/00203, SAF2015-67643-P, RD16/0008, RD16/0008/0026 and RD16/0008/0016) and by the Fundación Séneca, Agencia de Ciencia y Tecnología Región de Murcia (19881/GERM/15)

    Short- and Long-Term Study of the Impact of Focal Blue Light-Emitting Diode-Induced Phototoxicity in Adult Albino Rats

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    Background: In adult rats we study the short- and long-term effects of focal blue light-emitting diode (LED)-induced phototoxicity (LIP) on retinal thickness and Iba-1+ activation. Methods: The left eyes of previously dark-adapted Sprague Dawley (SD) rats were photoexposed to a blue LED (20 s, 200 lux). In vivo longitudinal monitoring of retinal thickness, fundus images, and optical retinal sections was performed from 1 to 30 days (d) after LIP with SD-OCT. Ex vivo, we analysed the population of S-cone and Iba-1+ cells within a predetermined fixed-size circular area (PCA) centred on the lesion. Results: LIP resulted in a circular focal lesion readily identifiable in vivo by fundus examination, which showed within the PCAs a progressive thinning of the outer retinal layer, and a diminution of the S-cone population to 19% by 30 d. In parallel to S-cone loss, activated Iba-1+ cells delineated the lesioned area and acquired an ameboid morphology with peak expression at 3 d after LIP. Iba-1+ cells adopted a more relaxed-branched morphology at 7 d and by 14–30 d their morphology was fully branched. Conclusion: LIP caused a progressive reduction of the outer retina with loss of S cones and a parallel dynamic activation of microglial cells in the lesioned area

    Pigment Epithelium-Derived Factor (PEDF) Fragments Prevent Mouse Cone Photoreceptor Cell Loss Induced by Focal Phototoxicity In Vivo

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    Here, we evaluated the effects of PEDF (pigment epithelium-derived factor) and PEDF peptides on cone-photoreceptor cell damage in a mouse model of focal LED-induced phototoxicity (LIP) in vivo. Swiss mice were dark-adapted overnight, anesthetized, and their left eyes were exposed to a blue LED placed over the cornea. Immediately after, intravitreal injection of PEDF, PEDF-peptide fragments 17-mer, 17-mer[H105A] or 17-mer[R99A] (all at 10 pmol) were administered into the left eye of each animal. BDNF (92 pmol) and bFGF (27 pmol) injections were positive controls, and vehicle negative control. After 7 days, LIP resulted in a consistent circular lesion located in the supratemporal quadrant and the number of S-cones were counted within an area centered on the lesion. Retinas treated with effectors had significantly greater S-cone numbers (PEDF (60%), 17-mer (56%), 17-mer [H105A] (57%), BDNF (64%) or bFGF (60%)) relative to their corresponding vehicle groups (≈42%). The 17-mer[R99A] with no PEDF receptor binding and no neurotrophic activity, PEDF combined with a molar excess of the PEDF receptor blocker P1 peptide, or with a PEDF-R enzymatic inhibitor had undetectable effects in S-cone survival. The findings demonstrated that the cone survival effects were mediated via interactions between the 17-mer region of the PEDF molecule and its PEDF-R receptor
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