52 research outputs found
Documenting the Recovery of Vascular Services in European Centres Following the Initial COVID-19 Pandemic Peak: Results from a Multicentre Collaborative Study
Objective: To document the recovery of vascular services in Europe following the first COVID-19 pandemic peak. Methods: An online structured vascular service survey with repeated data entry between 23 March and 9 August 2020 was carried out. Unit level data were collected using repeated questionnaires addressing modifications to vascular services during the first peak (March – May 2020, “period 1”), and then again between May and June (“period 2”) and June and July 2020 (“period 3”). The duration of each period was similar. From 2 June, as reductions in cases began to be reported, centres were first asked if they were in a region still affected by rising cases, or if they had passed the peak of the first wave. These centres were asked additional questions about adaptations made to their standard pathways to permit elective surgery to resume. Results: The impact of the pandemic continued to be felt well after countries’ first peak was thought to have passed in 2020. Aneurysm screening had not returned to normal in 21.7% of centres. Carotid surgery was still offered on a case by case basis in 33.8% of centres, and only 52.9% of centres had returned to their normal aneurysm threshold for surgery. Half of centres (49.4%) believed their management of lower limb ischaemia continued to be negatively affected by the pandemic. Reduced operating theatre capacity continued in 45.5% of centres. Twenty per cent of responding centres documented a backlog of at least 20 aortic repairs. At least one negative swab and 14 days of isolation were the most common strategies used for permitting safe elective surgery to recommence. Conclusion: Centres reported a broad return of services approaching pre-pandemic “normal” by July 2020. Many introduced protocols to manage peri-operative COVID-19 risk. Backlogs in cases were reported for all major vascular surgeries
The Influence of Different Anions on the Corrosion Resistance of Ti-6Al-4V Alloy in Simulated Acid Rainwater
Improving Power Quality Problems of Isolated MG Based on ANN Under Different Operating Conditions Through PMS and ASSC Integration
Microgrid (MG) technologies assist the power grid in evolving to become more efficient, less polluting, and more resilient by addressing the requirements of energy users. However, several technological issues arise as a result of the unpredictability and difficulty in estimating the efficacy and regulation of the many renewable energy resources (RERs) incorporated in MGs. Two of the most significant of these issues are maintaining system stability and power quality, which necessitate to get better the performance of the MGs. The most difficult challenge, system stability, can be achieved with successful Power Management System (PMS). This paper proposes an effective PMS for an AC MG equipped with a diesel generator (DG), a permanent magnet wind generator (PMWG), and a solar photovoltaic (PV) panel Based on an adaptable Artificial Neural Network (ANN). The ANN weights are properly tuned via the Enhanced Bald Eagle Search (EBES) optimization algorithm to produce a stable system during the whole training period, achieve MG energy balance, reduce the usage of fossil fuel DG and maintain MG voltage stability. In addition, for keeping power quality, an adaptive series shunt compensator (ASSC) is described in this work, along with a developed integrative PID controller, where the latter’s controller gains are ideally set utilizing the EBES optimization algorithm to perform adaptably with self-tuning when the operational circumstances of an MG change. various cases are displayed to test the strong of offered ASSC on harmonic mitigation, dynamic voltage stabilization, reactive power control and power factor correction. Moreover, comprehensive case study based on realistic on-site location for Zafarana region, Suez Gulf region of Egypt is proposed. Taking into account The changing nature of weather-related renewable energy, actual loads states and transient faults
Cellular and physiological circadian mechanisms drive diurnal cell proliferation and expansion of white adipose tissue.
Hyperplastic expansion of white adipose tissue (WAT) relies in part on the proliferation of adipocyte precursor cells residing in the stromal vascular cell fraction (SVF) of WAT. This study reveals a circadian clock- and feeding-induced diurnal pattern of cell proliferation in the SVF of visceral and subcutaneous WAT in vivo, with higher proliferation of visceral adipocyte progenitor cells subsequent to feeding in lean mice. Fasting or loss of rhythmic feeding eliminates this diurnal proliferation, while high fat feeding or genetic disruption of the molecular circadian clock modifies the temporal expression of proliferation genes and impinges on diurnal SVF proliferation in eWAT. Surprisingly, high fat diet reversal, sufficient to reverse elevated SVF proliferation in eWAT, was insufficient in restoring diurnal patterns of SVF proliferation, suggesting that high fat diet induces a sustained disruption of the adipose circadian clock. In conclusion, the circadian clock and feeding simultaneously impart dynamic, regulatory control of adipocyte progenitor proliferation, which may be a critical determinant of adipose tissue expansion and health over time
Publisher Correction: Cellular and physiological circadian mechanisms drive diurnal cell proliferation and expansion of white adipose tissue.
The original version of this Article contained an error in Ref. 72, which was incorrectly given with the wrong author names as: Mendez-Ferrer, S., Lucas, D., Battista, M. & Frenette, P. S. Age-associated telomere attrition in adipocyte progenitors predisposes to metabolic disease. Nat. Metab. 2, 1482–1497 (2020). The correct form of Ref. 72 is: Gao, Z. et al. Age-associated telomere attrition in adipocyte progenitors predisposes to metabolic disease. Nat. Metab. 2, 1482–1497 (2020). This has been corrected in the PDF and HTML versions of the Article
Restoration of the molecular clock is tumor suppressive in neuroblastoma
MYCN activation is a hallmark of advanced neuroblastoma (NB) and a known master regulator of metabolic reprogramming, favoring NB adaptation to its microenvironment. We found that the expression of the main regulators of the molecular clock loops is profoundly disrupted in MYCN-amplified NB patients, and this disruption independently predicts poor clinical outcome. MYCN induces the expression of clock repressors and downregulates the one of clock activators by directly binding to their promoters. Ultimately, MYCN attenuates the molecular clock by suppressing BMAL1 expression and oscillation, thereby promoting cell survival. Reestablishment of the activity of the clock activator RORα via its genetic overexpression and its stimulation through the agonist SR1078, restores BMAL1 expression and oscillation, effectively blocks MYCN-mediated tumor growth and de novo lipogenesis, and sensitizes NB tumors to conventional chemotherapy. In conclusion, reactivation of RORα could serve as a therapeutic strategy for MYCN-amplified NBs by blocking the dysregulation of molecular clock and cell metabolism mediated by MYCN
Application of Some Condensed Uracils as Corrosion Inhibitors for Mild Steel: Gravimetric, Electrochemical, Surface Morphological, UV–Visible, and Theoretical Investigations
Kinetic Consequences of Replacing the Internucleotide Phosphorus Atoms in DNA with Arsenic
Vesicles and Micelles from Amphiphilic Zinc(II)−Cyclen Complexes as Highly Potent Promoters of Hydrolytic DNA Cleavage
Phosphate esters are essential to any living organism and their specific hydrolysis plays an important role in many metabolic processes. As phosphodiester bonds can be extraordinary stable, as in DNA, great effort has been put into mimicking the active sites of hydrolytic enzymes which can easily cleave these linkages and were often found to contain one or more coordinated metal ions. With this in mind, we report micellar and vesicular Zn(II)–cyclen complexes which considerably promote the hydrolytic cleavage of native DNA and the activated model substrate bis(4-nitrophenyl)phosphate (BNPP). They are formed by self-assembly from amphiphilic derivatives of previously employed complexes in aqueous solution and therefore allow a simple and rapid connection of multiple active metal sites without great synthetic effort. Considering the hydrolytic cleavage of BNPP at 25 °C and pH 8, the micellar and vesicular metal catalysts show an increase of second-order rate constants (k2) by 4–7 orders of magnitude compared to the unimolecular complexes under identical conditions. At neutral pH, they produce the highest k2 values reported so far. For pBR322 plasmid DNA, both a conversion of the supercoiled to the relaxed and linear form, and also a further degradation into smaller fragments by double strand cleavages could be observed after incubation with the vesicular Zn(II)–complexes. Finally, even the cleavage of nonactivated single-stranded oligonucleotides could be considerably promoted compared to background reaction
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