1,228 research outputs found
Micro-Level Interactions in Business-Nonprofit Partnerships
While most research on business-nonprofit partnerships has focused on macro and meso perspectives, this paper pays attention to the micro level. Drawing on various theoretical perspectives from both marketing and management, we conceptually relate the outcomes of active employee participation in such partnerships to consumer self-interest. We also explore empirically whether and when self-interest affects consumersâ responses towards firms in relation to business-nonprofit partnerships. The study reveals that self-interest can directly influence consumersâ behavioral responses towards firms (i.e. switching and buying intentions, and word of mouth), whereas the impact on evaluative responses in terms of attitude and trust is only weak. The fit between the firm and the nonprofit partner (company-cause fit) turns out to moderate this effect, with consumer self-interest only playing a role if fit is high. Implications for research and practice are discussed
Variations des apports de litiÚre et d'éléments minéraux dans les plantations de limba (Terminalia superba) au Congo
Variations in Litter Production and Nutrient Supply in Plantations of Limba (Terminalia superba) in Congo. A study was carried out in a chronosequence of Terminalia superba (7, 12 and 48 years) and a nearby natural forest. The results show that the peaks of litterfall take place in rainy season contrary to the majority of the forest formations of the humid tropical zone. The return of nutrients to the soil via the leaf litter is higher in plantations than in forest. The calcium released from the leaf litter was up to 175 kg.ha-1.year1. The values obtained indicate a moderate nutrient use efficiency by Terminalia superba
What is the best protocol to cryopreserve immature mouse testicular cell suspensions?
Research question
From a clinical perspective, which parameters grant optimal cryopreservation of mouse testicular cell suspensions?
Design
We studied the effect of different cryopreservation rates, the addition of sugars, different vessels and the addition of an apoptotic inhibitor on the efficiency of testicular cell suspension cryopreservation. After thawing and warming, testicular cell suspensions were transplanted to recipient mice for further functional assay. After selecting the optimal cryopreservation procedure, a second experiment compared the transplantation efficiency between the selected freezing protocol and fresh testicular cell suspensions.
Results
Multiple- and single-step freezing did not differ significantly in terms of recovered viable cells (RVC) (33 ± 28% and 38 ± 25%). The addition of sucrose did not result in a higher RVC (33 ± 20%). Cells frozen in vials recovered better than those frozen in straws (52 ± 20% versus 33 ± 20%; P = 0.0049). The inclusion of an apoptosis inhibitor (z-VAD[Oe]-FMK) significantly increased the RVC after thawing (61 ± 18% versus 50 ± 17%; P = 0.0480). When comparing the optimal cryopreservation procedure with fresh testicular cell suspensions, a lower RVC (63 ± 11% versus 92 ± 4%; P < 0.0001) and number of donor-derived spermatogonial stem cell colonies per testis (34.04 ± 2.34 versus 16.78 ± 7.76; P = 0.0051) were observed.
Conclusion
Upon freezeâthawing or vitrificationâwarming, and assessment of donor-derived spermatogenesis after transplantation, Dulbecco's modified Eagle's medium supplemented with 1.5M dimethyl-sulphoxide, 10% fetal calf serum and 60â”M of Z-VAD-(OMe)-FMK in vials at a freezing rate of â1°C/min was optimal
Etude de la germination de cinq provenances de Tamarindusindica L. en conditions de stress hydrique au Sénégal
Ce prĂ©sent travail se propose dâĂ©valuer le comportement germinatif de cinq provenances de tamarinier (Tamarindus indica L.) dans des conditions de stress hydrique. Six concentrations croissantes 0 ; - 1,4 ; - 2,8 ; - 4,2 ; - 5,6 ; -7 bar de polyĂ©thylĂšne glycol (PEG 6000) ont Ă©tĂ© testĂ©es. Les rĂ©sultats ont montrĂ© une variabilitĂ© de la germination de lâespĂšce en fonction de lâintensitĂ© du stress et de la provenance. Le seuil critique de germination des provenances du tamarinier est de -7 bar. La provenance Sakkal de la zone sahĂ©lienne sâest montrĂ©e plus tolĂ©rante au stress hydrique avec un taux de germination de 2% en conditions de stress sĂ©vĂšre. Toutefois, ces faibles rĂ©sultats sont imputables aux conditions de conservation des graines. Ces informations sur l'Ă©cologie et la physiologie de la germination du tamarinier sont vitales, non seulement pour comprendre les variations gĂ©nĂ©tiques des diffĂ©rentes populations de tamarinier au SĂ©nĂ©gal, mais aussi pour dĂ©velopper des stratĂ©gies pour la conservation de la biodiversitĂ© et la restauration des forĂȘts tropicales.Mots clĂ©s : Germination, provenances, Tamarindus indica L., stress hydrique, SĂ©nĂ©gal
Comparative efficacy of intravenous premedication of clonidine versus nalbuphine on intraoperative hemodynamic profile of patients during surgery under general anesthesia: a randomized study
Background: Airway manipulation and surgical stimulation lead to variable changes in hemodynamic profile due to increase in plasma catecholamine levels, but these changes can be attenuated by appropriate premedication. The present study was designed to compare the clinical efficacy of intravenous premedication of clonidine with nalbuphine on intraoperative hemodynamic profile of patients during surgery under general anaesthesia.Methods: Sixty adult consenting patients of ASA physical status I and II of either gender were randomized into two groups of 30 patients each, to receive either intravenous clonidine (2 ÎŒg/kg) or nalbuphine (0.2 mg/kg), 10 min before induction with propofol. Direct laryngoscopy and intubation were facilitated with vecuronium bromide. Changes in heart rate, blood pressure and electrocardiogram were recorded at specific time intervals and were noted as primary variable. Any adverse effects and complications were recorded as secondary outcomes.Results: After laryngoscopy and intubation, the increase in mean heart rate and mean blood pressure occurred immediately in patients of both groups, but persisted up to 6 to 10 min in patients of clonidine group, thereafter the changes returned back to baseline values, while in patients of nalbuphine group, this increase persisted up to 8 to 10 min. The differences in hemodynamic changes between the groups were statistically significant throughout the surgery and post extubation.Conclusions: Intravenous clonidine was more effective than nalbuphine to attenuate the hemodynamics changes during stressful period of laryngoscopy, intubation and surgery
Vector casting for noise reduction
We report a new method for the reduction of noise from spectra. This method is based on casting vectors from one data point to the following data points of the noisy spectrum. The noiseâreduced spectrum is computed from the casted vectors within a margin that is identified by an envelopeâfinder algorithm. We compared here the presented method with the SavitzkyâGolay and the wavelet transform approaches for noise reduction using simulated Raman spectra of various signalâtoânoise ratios between 1 and 25 dB and experimentally acquired Raman spectra. The method presented here performs well compared with the SavitzkyâGolay and the waveletsâbased denoising method, especially at small signalâtoânoise ratios and furthermore relies on a minimum of human input requirements
Development and Disease-Dependent Dynamics of Spermatogonial Subpopulations in Human Testicular Tissues
Cancer therapy and conditioning treatments of non-malignant diseases affect spermatogonial function and may lead to male infertility. Data on the molecular properties of spermatogonia and the influence of disease and/or treatment on spermatogonial subpopulations remain limited. Here, we assessed if the density and percentage of spermatogonial subpopulation changes during development (n = 13) and due to disease and/or treatment (n = 18) in tissues stored in fertility preservation programs, using markers for spermatogonia (MAGEA4), undifferentiated spermatogonia (UTF1), proliferation (PCNA), and global DNA methylation (5mC). Throughout normal prepubertal testicular development, only the density of 5mC-positive spermatogonia significantly increased with age. In comparison, patients affected by disease and/or treatment showed a reduced density of UTF1-, PCNA- and 5mC-positive spermatogonia, whereas the percentage of spermatogonial subpopulations remained unchanged. As an exception, sickle cell disease patients treated with hydroxyurea displayed a reduction in both density and percentage of 5mC- positive spermatogonia. Our results demonstrate that, in general, a reduction in spermatogonial density does not alter the percentages of undifferentiated and proliferating spermatogonia, nor the establishment of global methylation. However, in sickle cell disease patients', establishment of spermatogonial DNA methylation is impaired, which may be of importance for the potential use of this tissues in fertility preservation programs
Evaluation of Human Interindividual Variation in Bioactivation of Estragole Using Physiologically Based Biokinetic Modeling
The present study investigates interindividual variation in liver levels of the proximate carcinogenic metabolite of estragole, 1âČ-hydroxyestragole, due to variation in two key metabolic reactions involved in the formation and detoxification of this metabolite, namely 1âČ-hydroxylation of estragole and oxidation of 1âČ-hydroxyestragole. Formation of 1âČ-hydroxyestragole is predominantly catalyzed by P450 1A2, 2A6, and 2E1, and results of the present study support that oxidation of 1âČ-hydroxyestragole is catalyzed by 17ÎČ-hydroxysteroid dehydrogenase type 2 (17ÎČ-HSD2). In a first approach, the study defines physiologically based biokinetic (PBBK) models for 14 individual human subjects, revealing a 1.8-fold interindividual variation in the area under the liver concentration-time curve (AUC) for 1âČ-hydroxyestragole within this group of human subjects. Variation in oxidation of 1âČ-hydroxyestragole by 17ÎČ-HSD2 was shown to result in larger effects than those caused by variation in P450 enzyme activity. In a second approach, a Monte Carlo simulation was performed to evaluate the extent of variation in liver levels of 1âČ-hydroxyestragole that could occur in the population as a whole. This analysis could be used to derive a chemical-specific adjustment factor (CSAF), which is defined as the 99th percentile divided by the 50th percentile of the predicted distribution of the AUC of 1âČ-hydroxyestragole in the liver. The CSAF was estimated to range between 1.6 and 4.0, depending on the level of variation that was taken into account for oxidation of 1âČ-hydroxyestragole. Comparison of the CSAF to the default uncertainty factor of 3.16 for human variability in biokinetics reveals that the default uncertainty factor adequately protects 99% of the populatio
Sharpening the Molecular Scissors: Advances in Gene-Editing Technology
The ability to precisely modify human genes has been made possible by the development of tools such as meganucleases, zinc finger nucleases, TALENs, and CRISPR/Cas. These now make it possible to generate targeted deletions, insertions, gene knock outs, and point variants; to modulate g
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