80 research outputs found

    Types of social help-seeking strategies in different and across specific task stages of a real, challenging long-term task and their role in academic achievement

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    Social help seeking (SHS) is an important strategy for successful self-regulated learning at all school levels. The aim of this longitudinal study is threefold: to ascertain the existence of different types of SHS strategies in various task stages of creating an individual academic paper, examine the extent to which these types of SHS strategies change in the course of that challenging long-term task and analyse the extent to which these types are relevant to academic achievement. This examination extends previous studies by adopting a task-specific, person-centred development perspective on SHS outside regular classroom instruction. In particular, we explore SHS types in the context of a real, long-term task, whereby aspects neglected in previous studies (need for help, help sources based on specific issue areas) are used for type creation and test for differences in academic achievement. Three online questionnaires were completed by 603 upper secondary school-level students (62.9% female) with a mean age of 17.3 (SD = .71) within one school year. Latent class analyses, latent transition analyses (LTA) and nonparametric procedures (Kruskal-Wallis H test, post hoc Dunn-Bonferroni test) were performed. Different SHS types were identified (independents, factual supervisor-focused, factual supervisor-focused and motivational family-focused, motivational family-focused, and factual and motivational family-focused) and found to vary over different task stages. Moreover, LTA indicated a considerable change between the SHS types over time. Nevertheless, no significant differences in achievement emerged between the types per task stage, thus reflecting the adage, 'There is more than one way of doing it'

    The relationship between success and failure causal attributions and achievement goal orientations

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    The aim of this study was to investigate whether four causal attributions for success and failure each (two internal and two external attributions) can be predicted by four types of achievement goal orientations, and whether achievement goal orientations are connected with the perception of a performance as a success (vs. a failure). We surveyed 690 high school students writing a school-leaving certificate paper over the course of one year. Of these, 565 students (65 % young women) considered their paper to be a success; 101 students (59 % young women) viewed it as a failure. A binominal logistic regression and two separate path models for the success and failure samples were conducted. The main findings showed that the odds of perceiving an outcome as a success were higher with mastery goals and performance-avoidance goals. Mastery goal and performance-approach goal orientation were positively related to internal success attributions. Mastery goal orientation was positively and performance-approach goal orientation was negatively connected with the failure attribution ‘popularity with the supervisor.’ Performance-avoidance goals were positively linked to external success attributions and negatively linked to the external failure attribution ‘luck.’ Work-avoidance goals predicted all types of success attributions but none of the failure attributions. The findings provide in-depth insights into attribution processes and highlight the importance of promoting a mastery goal orientation

    High Refractive Index Materials of Iron Sulfides and Poly(ethylene oxide)

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    High refractive index composites of iron sulfides and poly(ethylene oxide) (PEO) have been prepared by co-precipitation from aqueous solution. Several reaction parameters were varied: inorganic reactants, reactant ratios, reaction temperatures, and reaction times. Selected samples were characterized with organic microelemental analysis, x-ray fluorescence spectroscopy, x-ray diffraction, DSC, and TEM. The nanocomposites with the highest refractive indices have been prepared using PEO, Mohr's salt, and H2S or NaHS. The analyses indicate that the iron sulfides in these materials consist of finely dispersed mackinawite and greigite ("amorphous” FeS) and, partially, also pyrite. The refractive indexes of the resulting composites are clearly above 2 at 632.8 and 1295 nm and can assume values between 2.5 and 2.

    T-cadherin is present on endothelial microparticles and is elevated in plasma in early atherosclerosis

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    Aims The presence of endothelial cell (EC)-derived surface molecules in the circulation is among hallmarks of endothelial activation and damage in vivo. Previous investigations suggest that upregulation of T-cadherin (T-cad) on the surface of ECs may be a characteristic marker of EC activation and stress. We investigated whether T-cad might also be shed from ECs and in amounts reflecting the extent of activation or damage. Methods and results Immunoblotting showed the presence of T-cad protein in the culture medium from normal proliferating ECs and higher levels in the medium from stressed/apoptotic ECs. Release of T-cad into the circulation occurs in vivo and in association with endothelial dysfunction. Sandwich ELISA revealed negligible T-cad protein in the plasma of healthy volunteers (0.90 ± 0.90 ng/mL, n = 30), and increased levels in the plasma from patients with non-significant atherosclerosis (9.23 ± 2.61 ng/mL, n = 63) and patients with chronic coronary artery disease (6.93 ± 1.31 ng/mL, n = 162). In both patient groups there was a significant (P = 0.043) dependency of T-cad and degree of endothelial dysfunction as measured by reactive hyperaemia peripheral tonometry. Flow cytometry analysis showed that the major fraction of T-cad was released into the EC culture medium and the plasma as a surface component of EC-derived annexin V- and CD144/CD31-positive microparticles (MPs). Gain-of-function and loss-of-function studies demonstrate that MP-bound T-cad induced Akt phosphorylation and activated angiogenic behaviour in target ECs via homophilic-based interactions. Conclusion Our findings reveal a novel mechanism of T-cad-dependent signalling in the vascular endothelium. We identify T-cad as an endothelial MP antigen in vivo and demonstrate that its level in plasma is increased in early atherosclerosis and correlates with endothelial dysfunctio

    A test of positive suggestions about side effects as a way of enhancing the analgesic response to NSAIDs

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    Side effects are frequent in pharmacological pain management, potentially preceding analgesia and limiting drug tolerability. Discussing side effects is part of informed consent, yet can favor nocebo effects. This study aimed to test whether a positive suggestion regarding side effects, which could act as reminders of the medication having been absorbed, might favor analgesia in a clinical interaction model. Sixty-six healthy males participated in a study “to validate pupillometry as an objective measure of analgesia”. Participants were unknowingly randomized double-blind to positive vs control information about side effects embedded in a video regarding the study drugs. Sequences of moderately painful heat stimuli applied before and after treatment with diclofenac and atropine served to evaluate analgesia. Atropine was deceptively presented as a co-analgesic, but used to induce side effects. Adverse events (AE) were collected with the General Assessment of Side Effects (GASE) questionnaire prior to the second induced pain sequence. Debriefing fully informed participants regarding the purpose of the study and showed them the two videos.The combination of medication led to significant analgesia, without a between-group difference. Positive information about side effects increased the attribution of AE to the treatment compared to the control information. The total GASE score was correlated with analgesia, i.e., the more AEs reported, the stronger the analgesia. Interestingly, there was a significant between-groups difference on this correlation: the GASE score and analgesia correlated only in the positive information group. This provides evidence for a selective link between AEs and pain relief in the group who received the suggestion that AEs could be taken as a sign “that help was on the way”. During debriefing, 65% of participants said they would prefer to receive the positive message in a clinical context. Although the present results cannot be translated immediately to clinical pain conditions, they do indicate the importance of testing this type of modulation in a clinical context

    An improved method for isolation of microvascular endothelial cells from normal and inflamed human lung

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    Summary: Microvascular endothelial cells (MVEC), which differ from large vessel endothelial cells, have been isolated successfully from lungs of various species, including man. However, contamination by nonendothelial cells remains a major problem in spite of several technical improvements. In view of the organ specificity of MVEC, endothelial cells should be derived from the tissue involved in the diseases one wishes to study. Therefore, to investigate some of the immunopathological mechanisms leading to acute respiratory distress syndrome (ARDS), we have attempted to isolate lung MVEC from patients undergoing thoracic surgery for lung carcinoma and patients dying of ARDS. The method described here includes four main steps: (1) full digestion of pulmonary tissue with trypsin and collagenase, (2) aggregation of MVEC induced by human plasma, (3) Percoll density centrifugation, and (4) selection and transfer of MVEC after local digestion with trypsin/EDTA under light microscopy. Normal and ARDS-derived lung MVEC purified by this technique presented contact inhibition (i.e., grew in monolayer), and expressed classical endothelial markers, including von Willebrand factor (vWF), platelet endothelial cell adhesion molecule 1(PECAM-1, CD31), and transcripts for the angiogensin converting enzyme (ACE). The cells also formed capillarylike structures, took up high levels of acetylated low-density lipoprotein (Ac-LDL), and exhibited ELAM-1 inducibility in response to TNF. Contaminant cells, such as fibroblasts, smooth muscle cells, or pericytes, were easily recognized on the basis of morphology and were eliminated by selection of plasma-aggregated cells under light microscopy. The technique presented here allows one to study the specific involvement and contribution of pulmonary endothelium in various lung disease

    E119D Neuraminidase Mutation Conferring Pan-Resistance to Neuraminidase Inhibitors in an A(H1N1)pdm09 Isolate From a Stem-Cell Transplant Recipient

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    Background. An influenza A(H1N1)pdm09 infection was diagnosed in a hematopoietic stem cell transplant recipient during conditioning regimen. He was treated with oral oseltamivir, later combined with intravenous zanamivir. The H275Y neuraminidase (NA) mutation was first detected, and an E119D NA mutation was identified during zanamivir therapy. Methods. Recombinant wild-type (WT) E119D and E119D/H275Y A(H1N1)pdm09 NA variants were generated by reverse genetics. Susceptibility to NA inhibitors (NAIs) was evaluated with a fluorometric assay using the 2â€Č-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA) substrate. Susceptibility to favipiravir (T-705) was assessed using plaque reduction assays. The NA affinity and velocity values were determined with NA enzymatic studies. Results. We identified an influenza A(H1N1)pdm09 E119D mutant that exhibited a marked increase in the 50% inhibitory concentrations against all tested NAIs (827-, 25-, 286-, and 702-fold for zanamivir, oseltamivir, peramivir, and laninamivir, respectively). The double E119D/H275Y mutation further increased oseltamivir and peramivir 50% inhibitory concentrations by 790- and >5000-fold, respectively, compared with the WT. The mutant viruses remained susceptible to favipiravir. The NA affinity and velocity values of the E119D variant decreased by 8.1-fold and 4.5-fold, respectively, compared with the WT. Conclusions. The actual emergence of a single NA mutation conferring pan-NAI resistance in the clinical setting reinforces the pressing need to develop new anti-influenza strategie

    Essential and distinct roles for cdc42 and rac1 in the regulation of Schwann cell biology during peripheral nervous system development

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    During peripheral nervous system (PNS) myelination, Schwann cells must interpret extracellular cues to sense their environment and regulate their intrinsic developmental program accordingly. The pathways and mechanisms involved in this process are only partially understood. We use tissue-specific conditional gene targeting to show that members of the Rho GTPases, cdc42 and rac1, have different and essential roles in axon sorting by Schwann cells. Our results indicate that although cdc42 is required for normal Schwann cell proliferation, rac1 regulates Schwann cell process extension and stabilization, allowing efficient radial sorting of axon bundles

    Profilin 1 is required for peripheral nervous system myelination

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    Myelination allows rapid saltatory propagation of action potentials along the axon and is an essential prerequisite for the normal functioning of the nervous system. During peripheral nervous system (PNS) development, myelin-forming Schwann cells (SCs) generate radial lamellipodia to sort and ensheath axons. This process requires controlled cytoskeletal remodeling, and we show that SC lamellipodia formation depends on the function of profilin 1 (Pfn1), an actinbinding protein involved in microfilament polymerization. Pfn1 is inhibited upon phosphorylation by ROCK, a downstream effector of the integrin linked kinase pathway. Thus, a dramatic reduction of radial lamellipodia formation is observed in SCs lacking integrinlinked kinase or treated with the Rho/ROCK activator lysophosphatidic acid. Knocking down Pfn1 expression by lentiviralmediated shRNA delivery impairs SC lamellipodia formation in vitro, suggesting a direct role for this protein in PNS myelination. Indeed,SC-specific gene ablation of Pfn1 in mice led to profound radial sorting and myelination defects, confirming a central role for this protein in PNS development. Our data identify Pfn1 as a key effector of the integrin linked kinase/Rho/ROCK pathway. This pathway, acting in parallel with integrin ÎČ1/LCK/Rac1 and their effectors critically regulates SC lamellipodia formation, radial sorting and myelination during peripheral nervous system maturation

    Integrin-linked kinase is required for radial sorting of axons and Schwann cell remyelination in the peripheral nervous system

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    During development, Schwann cells (SCs) interpret different extracellular cues to regulate their migration, proliferation, and the remarkable morphological changes associated with the sorting, ensheathment, and myelination of axons. Although interactions between extracellular matrix proteins and integrins are critical to some of these processes, the downstream signaling pathways they control are still poorly understood. Integrin-linked kinase (ILK) is a focal adhesion protein that associates with multiple binding partners to link integrins to the actin cytoskeleton and is thought to participate in integrin and growth factor–mediated signaling. Using SC-specific gene ablation, we report essential functions for ILK in radial sorting of axon bundles and in remyelination in the peripheral nervous system. Our in vivo and in vitro experiments show that ILK negatively regulates Rho/Rho kinase signaling to promote SC process extension and to initiate radial sorting. ILK also facilitates axon remyelination, likely by promoting the activation of downstream molecules such as AKT/protein kinase B
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