University of Fribourg

About: University of Fribourg is a education organization based out in Fribourg, Freiburg, Switzerland. It is known for research contribution in the topics: Population & Context (language use). The organization has 6040 authors who have published 14975 publications receiving 542500 citations. The organization is also known as: UNIFR & Universität Freiburg.

Mature adipocytes and perivascular adipose tissue stimulate vascular smooth muscle cell proliferation: effects of aging and obesity.

Abstract: Adipocytes and perivascular adipose tissue are emerging as regulators of vascular function. The effects of adipocytes and perivascular adipose tissue on human smooth muscle cell (SMC) proliferation were investigated. Conditioned medium was prepared from cultured premature and differentiated 3T3-L1 adipocytes and from periaortic adipose tissue from young (3 mo) and old (24 mo) Wistar-Kyoto (WKY) rats, lean and obese Zucker rats (3 mo), and WKY rats fed normal chow or a high-fat diet for 3 mo. Conditioned medium from differentiated (but not premature) adipocytes stimulated SMC proliferation, which was abolished by charcoal and proteinase K treatment but was resistant to heat, trypsin, or phospholipase B (to hydrolyze lysophosphatidic acid). Further experiments demonstrated that the growth factor(s) are hydrosoluble and present in the fraction of molecular mass >100 kDa. Moreover, conditioned medium from periaortic adipose tissue stimulated SMC proliferation, which was significantly enhanced in aged rats and in rats fed a high-fat diet but not in obese Zucker rats deficient in functional leptin receptors. In conclusion, mature adipocytes release hydrosoluble protein growth factor(s) with a molecular mass >100 kDa for SMCs. Perivascular adipose tissue stimulates SMC proliferation, which is enhanced in aged WKY and in high-fat, diet-induced obesity but not in leptin receptor-deficient obese Zucker rats. These adipocyte-derived growth factor(s) and the effect of perivascular adipose tissue may be involved in vascular disease associated with aging and obesity.

A New Arabic Printed Text Image Database and Evaluation Protocols

Abstract: We report on the creation of a database composed of images of Arabic Printed words. The purpose of this database is the large-scale benchmarking of open-vocabulary, multi-font, multi-size and multi-style text recognition systems in Arabic. The challenges that are addressed by the database are in the variability of the sizes, fonts and style used to generate the images. A focus is also given on low-resolution images where anti-aliasing is generating noise on the characters to recognize. The database is synthetically generated using a lexicon of 113’284 words, 10 Arabic fonts, 10 font sizes and 4 font styles. The database contains 45’313’600 single word images totaling to more than 250 million characters. Ground truth annotation is provided for each image. The database is called APTI for Arabic Printed Text Images.

Refining the vulnerability model of low self-esteem and depression: Disentangling the effects of genuine self-esteem and narcissism.

Abstract: A growing body of research supports the vulnerability model of low self-esteem and depression, which states that low self-esteem is a risk factor for depression. The goal of the present research was to refine the vulnerability model, by testing whether the self-esteem effect is truly due to a lack of genuine self-esteem or due to a lack of narcissistic self-enhancement. For the analyses, we used data from 6 longitudinal studies consisting of 2,717 individuals. In each study, we tested the prospective effects of self-esteem and narcissism on depression both separately for each construct and mutually controlling the constructs for each other (i.e., a strategy that informs about effects of genuine self-esteem and pure narcissism), and then meta-analytically aggregated the findings. The results indicated that the effect of low self-esteem holds when narcissism is controlled for (uncontrolled effect = -.26, controlled effect = -.27). In contrast, the effect of narcissism was close to zero when self-esteem was controlled for (uncontrolled effect = -.06, controlled effect = .01). Moreover, the analyses suggested that the self-esteem effect is linear across the continuum from low to high self-esteem (i.e., the effect was not weaker at very high levels of self-esteem). Finally, self-esteem and narcissism did not interact in their effect on depression; that is, individuals with high self-esteem have a lower risk for developing depression, regardless of whether or not they are narcissistic. The findings have significant theoretical implications because they strengthen the vulnerability model of low self-esteem and depression.

Task difficulty in mental arithmetic affects microsaccadic rates and magnitudes

Abstract: Microsaccades are involuntary, small-magnitude saccadic eye movements that occur during attempted visual fixation. Recent research has found that attention can modulate microsaccade dynamics, but few studies have addressed the effects of task difficulty on microsaccade parameters, and those have obtained contradictory results. Further, no study to date has investigated the influence of task difficulty on microsaccade production during the performance of non-visual tasks. Thus, the effects of task difficulty on microsaccades, isolated from sensory modality, remain unclear. Here we investigated the effects of task difficulty on microsaccades during the performance of a non-visual, mental arithmetic task with two levels of complexity. We found that microsaccade rates decreased and microsaccade magnitudes increased with increased task difficulty. We propose that changes in microsaccade rates and magnitudes with task difficulty are mediated by the effects of varying attentional inputs on the rostral superior colliculus activity map.

Fission yeast Rad50 stimulates sister chromatid recombination and links cohesion with repair

Abstract: To study the role of Rad50 in the DNA damage response, we cloned and deleted the Schizosaccharo myces pombe RAD50 homologue The deletion is sensitive to a range of DNA-damaging agents and shows dynamic epistatic interactions with other recombination?repair genes We show that Rad50 is necessary for recombinational repair of the DNA lesion at the mating-type locus and that rad50 shows slow DNA replication We also find that Rad50 is not required for slowing down S phase in response to hydroxy urea or methyl methanesulfonate (MMS) treatment Interestingly, in rad50 cells, the recombination frequency between two homologous chromosomes is increased at the expense of sister chromatid recombination We propose that Rad50, an SMC-like protein, promotes the use of the sister chromatid as the template for homologous recombinational repair In support of this, we found that Rad50 functions in the same pathway for the repair of MMS-induced damage as Rad21, the homologue of the Saccharomyces cerevisiae Scc1 cohesin protein We speculate that Rad50 interacts with the cohesin complex during S phase to assist repair and possibly re-initiation of replication after replication fork collapse