996 research outputs found

    Reversible low-light induced photoswitching of crowned spiropyran-DO3A complexed with gadolinium(III) ions.

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    Photoswitchable spiropyran has been conjugated to the crowned ring system DO3A, which improves its solubility in dipolar and polar media and stabilizes the merocyanine isomer. Adding the lanthanide ion gadolinium(III) to the macrocyclic ring system leads to a photoresponsive magnetic resonance imaging contrast agent that displays an increased spin-lattice relaxation time (T₁) upon visible light stimulation. In this work, the photoresponse of this photochromic molecule to weak light illumination using blue and green light emitting diodes was investigated, simulating the emission spectra from bioluminescent enzymes. Photon emission rate of the light emitting diodes was changed, from 1.75 × 10¹⁶ photons·s⁻¹ to 2.37 × 10¹² photons·s⁻¹. We observed a consistent visible light-induced isomerization of the merocyanine to the spiropyran form with photon fluxes as low as 2.37 × 10¹² photons·s⁻¹ resulting in a relaxivity change of the compound. This demonstrates the potential for use of the described imaging probes in low light level applications such as sensing bioluminescence enzyme activity. The isomerization behavior of gadolinium(III)-ion complexed and non-complexed spiropyran-DO3A was analyzed in water and ethanol solution in response to low light illumination and compared to the emitted photon emission rate from over-expressed Gaussia princeps luciferase

    Evolution of phytosterols in Chardonnay grape berry skins during last stages of ripening

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    This study presents the results of rapid phytosterols analysis in grape skins during last stages of ripening. The analysis is related to the evolution of sterol content by comparison with ripening degree on two vineyards of Chardonnay grape variety in Burgundy: Meursault ler Cru and Hautes Cotes de Beaune. The characterization of sterols is realized by using combined gas chromatography-mass spectrometry from trimethylsilyl ethers of sterols. After optimization of extraction by azeotropic mixture (chloroform/methanol 2:1 v/v), the analysis allows to identify four sterols in grape skins: beta-sitosterol, campesterol, stigmasterol and lanosterol. In all the samples, beta-sitosterol is the major phytosterol (86 to 89 % of the total detected phytosterols). The evolution of phytosterols content during last stages of ripening shows a similar comportment of β-sitosterol, campesterol and stigmasterol in grape skins: the maturation induces a loss of phytosterols in grape skins. An increase of phytosterol contents occurs at peak maturity and can be related with over-maturation phenomenon. The relationship between phytosterol content in grape skins and S/A ratio indicates a markedly negative correlation

    Is rurality, area deprivation, access to outside space and green space associated with mental health during the Covid-19 pandemic?:A cross sectional study from the Covid-19 Health and Adherence Research in Scotland (CHARIS) project

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    Objectives To determine if rurality, area deprivation, access to outside space (Study 1) and frequency of visiting and duration in green space (Study 2) are associated with mental health during the Covid-19 pandemic. Design Serial, weekly, nationally representative, cross-sectional, observational study of randomly selected adults in Scotland during June and July 2020. Methods If available, validated instruments were used to measure psychological distress, individual demographics and illness beliefs and the following environments: rurality, area deprivation, access to residential outside space, frequency of visiting, and duration in green space. Simple linear regressions followed by examination of moderation effect. Results 2969 participants in Study 1, of which, 1765 (59.6%) female, 349 (11.9%) in the shielding category, median age 54 years. 502 participants in Study 2, of which, 295 (58.60%) female, 58 (11.6%) in shielding category, median age 53 years. Direct effects show that psychological distress was worse if: younger, female, in shielding category (demographics), worse illness (Covid-19) representations and greater threat perception (illness beliefs), if urban, in a deprived area, no access to or sharing residential outside space, and fewer visits to green space (environment). Moderation analyses show that environment amplify the direct effects of the individual factors on psychological distress. Conclusions Environment is important for mental health during pandemics and this study offers pointers for public health and for environmental planning, design and management, including housing design and public open space provision and regulation

    A rat model of early stage osteonecrosis induced by glucocorticoids

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    <p>Abstract</p> <p>Background</p> <p>Glucocorticoid (GC)-induced osteonecrosis (ON) is an important complication of medical therapy. The exact pathomechanisms of ON has not been clearly elucidated. There is a need for a reproducible animal model that better approximates the clinical scenario.</p> <p>Methods</p> <p>To determine the genetic susceptibility of rats to develop GC-induced femoral head ON, we evaluated 5 different inbred strains of rats (Spontaneous Hypertensive Rat, Wistar Kyoto, Wistar Furth, SASCO Fisher and Lewis). Prednisone pellets (dosage of 1.82-2.56 mg/kg/day) were implanted subcutaneously for 90. After 90 days, the femurs were resected and examined histologically and radiographically. Pathological and histological examination was performed. Hematoxylin and eosin (H & E) staining was used to delineate the femoral head osteonecrosis lesions as well as abnormalities of articular cartilage and growth plate.</p> <p>Results</p> <p>The greatest differences in H & E staining were seen in the Wistar Kyoto and Wistar Furth groups. In these groups 4 out of 5 and 3 out of 5, respectively, steroid-induced rats revealed growth plate disruption with acellular areas. The TUNEL apoptosis staining assay for apoptosis revealed that 4 out of 5 of Wistar Kyoto rats, 5 out of 5 of Wistar Furth, 2 out of 4 of surviving Lewis and 2 out of 2 of the surviving spontaneous hypertensive rats had apoptotic osteocytes in trabeculae, whereas none of the Fisher rats showed apoptotic osteocytes.</p> <p>Conclusions</p> <p>We postulate that Wistar Kyoto, Wistar Furth and spontaneous hypertensive rats may be strains of rats more susceptible to develop ON of the femoral head while Fisher rats were the most resistant.</p

    The effect of opioid therapy on sleep quality in patients with chronic non-malignant pain : a systematic review and exploratory meta-analysis

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    Current guidelines recommend opioid therapy to chronic non-malignant pain (CNP) patients when the benefits for pain and function outweigh risks. This systematic review examined the effects of opioid therapy on sleep – a valued functional outcome– in CNP. Electronic and hand searches of relevant studies up through July 2017 identified 18 eligible studies providing data from 3,746 CNP patients for analysis. Twelve of these studies were randomised controlled trials (RCTs) of up to 12-month in duration. Low-medium dosed oxycodone and transdermal fentanyl were the most tested therapies (n=4 each). Only two studies used objective sleep measure in addition to self-report ratings, questionnaires or sleep diary. Whilst calmer sleep with less body/leg movements and fewer awakenings could be achieved following opioid therapy, these might occur with increased sleep-disordered breathing and a much-shortened rapid eye movement (REM) sleep latency. Both the narrative synthesis and exploratory meta-analysis suggest that opioid therapy in CNP is associated with improved self-reported sleep quality. However, the effect is inconsistent, small (Standardised Mean Difference = 0.36), and may be accompanied by excessive daytime sleepiness. As a Cochrane-recommended assessment revealed “unclear” or “high” overall risk of bias for all studies, future opioid trials of stronger methodology and better reporting are needed to confirm and elucidate the effect

    Karyopherin enrichment and compensation fortifies the nuclear pore complex against nucleocytoplasmic leakage

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    Nuclear pore complexes (NPCs) discriminate nonspecific macromolecules from importin and exportin receptors, collectively termed "karyopherins" (Kaps), that mediate nucleocytoplasmic transport. This selective barrier function is attributed to the behavior of intrinsically disordered phenylalanine-glycine nucleoporins (FG Nups) that guard the NPC channel. However, NPCs in vivo are typically enriched with different Kaps, and how they impact the NPC barrier remains unknown. Here, we show that two major Kaps, importinβ1/karyopherinβ1 (Kapβ1) and exportin 1/chromosomal maintenance 1 (CRM1), are required to fortify NPC barrier function in vivo. Their enrichment at the NPC is sustained by promiscuous binding interactions with the FG Nups, which enable CRM1 to compensate for the loss of Kapβ1 as a means to maintain NPC barrier function. However, such a compensatory mechanism is constrained by the cellular abundances and different binding kinetics for each respective Kap, as evidenced for importin-5. Consequently, we find that NPC malfunction and nucleocytoplasmic leakage result from poor Kap enrichment

    Effect of FEM choices in the modelling of incremental forming of aluminium sheets

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    peer reviewedThis paper investigates the process of single point incremental forming of an aluminium cone with a 50-degree wall angle. Finite element (FE) models are established to simulate the process. Different FE packages have been used. Various aspects associated with the numerical choices as well as the material and process parameters have been studied. The final geometry and the reaction forces are presented as the results of the simulations. Comparison between the simulation results and the experimental data is also made
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