318 research outputs found

    Chemical and metallurgical analyses of 6Al-4V titanium test specimens exposed to hydrazine /N2H2/ liquid propellant

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    Chemical and metallurgical analyses of 6Al-4V titanium test specimens exposed to hydrazine /N2H2/ liquid propellan

    Characteristics of the Male Reproductive System and Spermatozoa of Leptophlebiidae (Ephemeroptera)

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    This study describes morphological changes in the male reproductive system of Miroculis amazonicus (Savage & Peters) from mature nymphs to subimago stages. The sperm ultrastructure of Massartela brieni (Lestage), Farrodes carioca (Domínguez et al) and Miroculis mourei (Savage & Peters), as well as aspects of cell fragments observed in these species' subimagos deferent ducts were described. Sperm from the three species studied are aflagellated and immotile, while those from F. carioca and Ma. brieni are approximately spherical with a homogenous nucleus and acrosome. Sperm of F. carioca present two or three mitochondria located between the nucleus and the acrosome. In Ma. brieni, only one lateral mitochondria was found. Sperm from Mi. mourei are shaped as a number 'eight', with electron lucent spots inside the nucleus and two mitochondria above the acrosome. Large cell fragments containing degenerative vesicles and some sperm were observed in the deferent duct lumen of the three species. Testes of Mi. amazonicus are extremely reduced in the subimago stage, which suggests that these cell fragments originated from testes degeneration.103107Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES

    The cytocompatibility and early osteogenic characteristics of an injectable calcium phosphate cement.

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    In this study, the cytocompatibility and early osteogenic characteristics of rat bone marrow cells (RBMCs) on injectable calcium phosphate (CaP) cement (Calcibon) were investigated. In addition to unmodified CaP cement discs, 2 other treatments were given to the discs: preincubation in MilliQ and sintering at different temperatures. After primary culture, RBMCs were dropwise seeded on the discs and cultured for 12 days. The samples were evaluated in terms of cell viability, morphology (live and dead assays and scanning electron microscopy (SEM)), cell proliferation (deoxyribonucleic acid (DNA) analyses), early cell differentiation (alkaline phosphatase (ALP) activity), and physicochemical analyses (xray diffraction (XRD)). The live and dead, DNA, and SEM results showed that Calcibon discs without any additional treatment were not supporting osteoblast-like cells in vitro. There were fewer cells, and cell layers were detached from the disc surface. Therefore, different preincubation periods and sintering temperatures were evaluated to improve the cytocompatibility of the CaP cement. Preincubating discs in MilliQ for periods of 1, 4, 8, and 12 weeks resulted in the hydrolysis of a-tri calcium phosphate (TCP) into an apatite-like structure with some b-TCP, as shown with XRD, but the material was not cytocompatible. Sintering the discs between 8008C and 11008C resulted in conversion of a-TCP to b-TCP with some hydroxyapatite and an increase in crystallinity. Eventually, the discs sintered at 11008C achieved better cell attachment, more-abundant cell proliferation, and earlier differentiation than other sintered (6008C, 8008C, and 10008C), preincubated, and unmodified specimens. On basis of our results, we conclude that in vivo results with CaP-based cements do not guarantee in vitro applicability. Furthermore, unmodified Calcibon is not cytocompatible in vitro, although preincubation of the material results in a more-favorable cell response, sintering of the material at 11008C results in the best osteogenic properties. In contrast to in vivo studies, the Calcibon CaP cement is not suitable as a scaffold for cellbased tissue-engineering strategies

    Bone regenerative properties of injectable PGLA-CaP composite with TGF-beta1 in a rat augmentation model.

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    The aim of this study was to examine the bone augmentation properties of an injectable composite consisting of PLGA microspheres/CaP cement (20/80), and the additional effect of loading PLGA microspheres with TGF-β1 (200 ng). For this purpose, PLGA/CaP composites (control) and PLGA/CaP composites loaded with TGF-β1 (test group) were injected on top of the skulls of 24 Wistar rats. Each rat received 2 materials from the same experimental group, and in total 48 implants were placed (n = 8). After 2, 4, and 8 weeks the results were evaluated histologically and histomorphometrically. The contact length between the implants and newly formed bone increased in time, and was significantly higher for the TGF-β1-loaded composites after 2 weeks. Also, bone formation was significantly higher for the TGF-β1-loaded composites (18.5% ± 3) compared to controls (7.21% ± 5) after 8 weeks of implantation. Immunohistochemical staining demonstrated massive inflammatory infiltrates in both groups, particularly at 2 weeks, which decreased substantially at 4 and 8 weeks. In conclusion, injectable PLGA/CaP composites stimulated bone augmentation in a rat model. The addition of TGF-β1 to the composite significantly increased bone contact at 2 weeks and enhanced new bone formation at 8 weeks

    Mechanical evaluation of implanted calcium phosphate cement incorporated with PLGA microparticles

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    In this study, the mechanical properties of an implanted calcium phosphate (CaP) cement incorporated with 20wt% poly (DL-lactic-coglycolic acid) (PLGA) microparticles were investigated in a rat cranial defect. After 2, 4 and 8 weeks of implantation, implants were evaluated mechanically (push-out test) and morphologically (Scanning Electron Microscopy (SEM) and histology). The results of the push-out test showed that after 2 weeks the shear strength of the implants was 0.4470.44MPa (average7sd), which increased to 1.3471.05MPa at 4 weeks and finally resulted in 2.6072.78MPa at 8 weeks. SEM examination showed a fracture plane at the bone–cement interface at 2 weeks, while the 4- and 8-week specimens created a fracture plane into the CaP/PLGA composites, indicating an increased strength of the bone–cement interface. Histological evaluation revealed that the two weeks implantation period resulted in minimal bone ingrowth, while at 4 weeks of implantation the peripheral PLGA microparticles were degraded and replaced by deposition of newly formed bone. Finally, after 8 weeks of implantation the degradation of the PLGA microparticles was almost completed, which was observed by the bone ingrowth throughout the CaP/PLGA composites. On basis of our results, we conclude that the shear strength of the bone–cement interface increased over time due to bone ingrowth into the CaP/PLGA composites. Although the bone–cement contact could be optimized with an injectable CaP cement to enhance bone ingrowth, still the mechanical properties of the composites after 8 weeks of implantation are insufficient for load-bearing purpose

    Acute effects of LSD on amygdala activity during processing of fearful stimuli in healthy subjects

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    Lysergic acid diethylamide (LSD) induces profound changes in various mental domains, including perception, self-awareness and emotions. We used functional magnetic resonance imaging (fMRI) to investigate the acute effects of LSD on the neural substrate of emotional processing in humans. Using a double-blind, randomised, cross-over study design, placebo or 100 μg LSD were orally administered to 20 healthy subjects before the fMRI scan, taking into account the subjective and pharmacological peak effects of LSD. The plasma levels of LSD were determined immediately before and after the scan. The study (including the a priori-defined study end point) was registered at ClinicalTrials.gov before study start (NCT02308969). The administration of LSD reduced reactivity of the left amygdala and the right medial prefrontal cortex relative to placebo during the presentation of fearful faces (P<0.05, family-wise error). Notably, there was a significant negative correlation between LSD-induced amygdala response to fearful stimuli and the LSD-induced subjective drug effects (P<0.05). These data suggest that acute administration of LSD modulates the engagement of brain regions that mediate emotional processing

    LSD Acutely Impairs Fear Recognition and Enhances Emotional Empathy and Sociality

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    Lysergic acid diethylamide (LSD) is used recreationally and has been evaluated as an adjunct to psychotherapy to treat anxiety in patients with life-threatening illness. LSD is well-known to induce perceptual alterations, but unknown is whether LSD alters emotional processing in ways that can support psychotherapy. We investigated the acute effects of LSD on emotional processing using the Face Emotion Recognition Task (FERT) and Multifaceted Empathy Test (MET). The effects of LSD on social behavior were tested using the Social Value Orientation (SVO) test. Two similar placebo-controlled, double-blind, random-order, crossover studies were conducted using 100 μg LSD in 24 subjects and 200 μg LSD in 16 subjects. All of the subjects were healthy and mostly hallucinogen-naive 25- to 65-year-old volunteers (20 men, 20 women). LSD produced feelings of happiness, trust, closeness to others, enhanced explicit and implicit emotional empathy on the MET, and impaired the recognition of sad and fearful faces on the FERT. LSD enhanced the participants' desire to be with other people and increased their prosocial behavior on the SVO test. These effects of LSD on emotion processing and sociality may be useful for LSD-assisted psychotherapy

    Effort reduction and the large fish indicator: Spatial trends reveal positive impacts of recent European fleet reduction schemes

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    The large fish indicator (LFI), or ‘proportion of fish greater than 40 cm length in bottom trawl surveys,’ is a frequently debated indicator of Good Environmental Status in European regional seas. How does the LFI respond to changes in fishing pressure? This question is addressed here through analysis of fine-scale spatial trends in the LFI within the North Sea, compared between two periods of contrasting fisheries management: 1983–1999 and 2000–2012, respectively, before and after the onset of the European Union's fleet reduction scheme. Over the entire period, the LFI has decreased in large parts of the North Sea. However, most of the decline was from 1983–1999; since 2000 the LFI has improved in much of the North Sea, especially in UK waters. Comparison with international effort data shows that those western areas where the LFI has improved correspond with regions where otter trawl effort has decreased since 2000 (and previously was highest in the 1990s), and also with decreases in beam trawl effort. This study provides strong support that recent European effort reduction schemes are now beginning to result in an improved ecosystem state as indicated by the regional-scale improvement in the LFI

    STECF Multiannual management plans SWW and NWW (STECF-15-08)

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    The STECF was tasked with an analysis of the likely effects of proposed management plans for the Southwestern (Bay of Biscay and Iberia) and Northwestern (Celtic sea) waters. Quantitative analyses were carried out to compare the likely effect of those management plans and of the direct application of the CFP on both stocks and fleets involved in these fisheries. Based on the results of simulations of the provisions of the proposed management plans, STECF concluded that, setting fishing opportunities in line with single-species FMSY ranges will provide managers with additional flexibility compared to the basic provisions of the 2013 CFP. Such flexibility is likely to help alleviate the problem of mismatches in quota availability in mixed-species fisheries thereby reducing the risk of early closure of some fisheries due to choke species. Adopting FMSY ranges will therefore increase the likelihood that desired exploitation rates will be achieved and will reduce the risk that some fishing fleets will go out of business. STECF considers that it is crucial that managers take note that persistent fishing at the upper limits of the FMSY ranges across all or most stocks simultaneously negates the flexibility introduced by the FMSY ranges and greatly increases the risk of overfishing. Such an approach will also increase the risk that the objectives of the CFP will not be achieved. STECF concludes that single species biomass safeguards for all stocks should be maintained to provide a basic level of protection. STECF notes that for the fleets affected by the SWW MAP, those providing the highest employment are generally not dependent to a great extent on the species that will be regulated through the MAP proposals. STECF notes that in the NWW there are some fleets which provide significant levels of employment and seem to be very dependent on the species that will be regulated through the MAP proposals. Nevertheless, there are a number of fleets in the NWW area that are not included in the employment analysis because of an absence of appropriate data. .Regarding the number and scope of MAPs as currently defined, STECF considers that a MAP covering a wider geographic area has advantages in terms of reducing management overheads and avoiding multiple regulations affecting the sector. A larger MAP area however, may have disadvantages associated with reducing the emphasis on local management measures and this may discourage the involvement of stakeholders, although this effect will depend on how the process of regionalization operates within the MAP. To evaluate the question of whether management of the species that drive the fisheries adequately allows for the management of by-catch species, the EWG carried out an analysis of correlations between catches of driver species identified in the plan and a variety of by-catch species. The analysis suggested only limited correlation. In view of this, the STECF notes that it is unlikely that relying on the TAC of the driver species to manage other species will be effective, in accordance with CFP requirements. STECF however notes that when analysis was performed at the fleet level, there were more obvious correlations, suggesting some scope to use fleet related management measures for the driver species as a way of managing some of the bycatch species. STECF therefore concludes that management of exploitation rates of non-driver (or bycatch) species is unlikely to occur as an automatic consequence of the management of the main (driver) stocks by TAC considered in the MAP.DG MAR

    Increased thalamic resting-state connectivity as a core driver of LSD-induced hallucinations

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    It has been proposed that the thalamocortical system is an important site of action of hallucinogenic drugs and an essential component of the neural correlates of consciousness. Hallucinogenic drugs such as LSD can be used to induce profoundly altered states of consciousness, and it is thus of interest to test the effects of these drugs on this system.; 100 μg LSD was administrated orally to 20 healthy participants prior to fMRI assessment. Whole brain thalamic functional connectivity was measured using ROI-to-ROI and ROI-to-voxel approaches. Correlation analyses were used to explore relationships between thalamic connectivity to regions involved in auditory and visual hallucinations and subjective ratings on auditory and visual drug effects.; LSD caused significant alterations in all dimensions of the 5D-ASC scale and significantly increased thalamic functional connectivity to various cortical regions. Furthermore, LSD-induced functional connectivity measures between the thalamus and the right fusiform gyrus and insula correlated significantly with subjective auditory and visual drug effects.; Hallucinogenic drug effects might be provoked by facilitations of cortical excitability via thalamocortical interactions. Our findings have implications for the understanding of the mechanism of action of hallucinogenic drugs and provide further insight into the role of the 5-HT2A -receptor in altered states of consciousness
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