93 research outputs found
The Effect of Aqueous Ammonia Soaking Pretreatment on Methane Generation Using Different Lignocellulosic Biomasses
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
Chromo- and Fluorogenic Organometallic Sensors
Compounds that change their absorption and/or emission properties in the presence of a target ion or molecule have been studied for many years as the basis for optical sensing. Within this group of compounds, a variety of organometallic complexes have been proposed for the detection of a wide range of analytes such as cations (including H+), anions, gases (e.g. O 2, SO2, organic vapours), small organic molecules, and large biomolecules (e.g. proteins, DNA). This chapter focuses on work reported within the last few years in the area of organometallic sensors. Some of the most extensively studied systems incorporate metal moieties with intense long-lived metal-to-ligand charge transfer (MLCT) excited states as the reporter or indicator unit, such as fac-tricarbonyl Re(I) complexes, cyclometallated Ir(III) species, and diimine Ru(II) or Os(II) derivatives. Other commonly used organometallic sensors are based on Pt-alkynyls and ferrocene fragments. To these reporters, an appropriate recognition or analyte-binding unit is usually attached so that a detectable modification on the colour and/or the emission of the complex occurs upon binding of the analyte. Examples of recognition sites include macrocycles for the binding of cations, H-bonding units selective to specific anions, and DNA intercalating fragments. A different approach is used for the detection of some gases or vapours, where the sensor's response is associated with changes in the crystal packing of the complex on absorption of the gas, or to direct coordination of the analyte to the metal centre
SOLID-STATE POLYMERIZATION OF BIS(TRICHLOROPHENOXO) COBALT(II) COMPLEX TO GIVE POLY(DICHLOROPHENYLENE OXIDE)
Synthesis of four-coordinated (tetrahedral) trichlorophenol cobalt(II) complex with neutral ligand pyridine was achieved from the aqueous solution and its characterization was performed by UV-visible, IR spectral and CHN analysis. Solid state thermal polymerization of the complex was accomplished first at constant temperature employing different time intervals and secondly at constant decomposition time. The poly(dichlorophenylene oxide)s so synthesized were characterized by IR, H-1 NMR and C-13 NMR spectral analysis, T(g) determination, as well as measurement of molecular weight by a viscometric method
Polymerisation of bis(trichlorophenolato)tri(pyridine)nickel and bis (trihalophenolato)di(pyridine)nickel (II) complexes in solid state
The synthesis of five-coordinated bis(trihalophenolato)tri (pyridine)nickel (II) and four-coordinated his (trihalophenolato)di(pyridine) nickel(II) complexes from an aqueous solution and their characterisation by FT-IR, X-ray, DSC and elemental analysis is described. The thermal polymerisation of these complexes was carried out in the solid state and in the melt. Structural analyses were performed using H-1 NMRI C-13 NMR and FT-IR spectroscopic analyses. T(g)s were determined by differential thermal analysis and the molecular weights by viscometric method
Ultrasonic study of magnetic structure of rare earth metals
On a employé les valeurs de la constante élastique c33 de Tb pour construire un diagramme de phase magnétique de l'élément. Les résultats sont comparés à des mesures antérieures sur Dy, Tb-50 % Ho et Gd-40 % Y.Measurements of the elastic constant c33 of Tb have been used to construct a magnetic phase diagram of the element. The results are discussed in conjunction with earlier measurements on Dy, Tb-50 % Ho and Gd- 40 % Y
Crystal Structure Of Bis(Pyridine)Bis(2,4,6-Tribromophenolato)Cobalt(Ii), C22H14Br6Con2O2
WoSScopu
Metal to ligand charge-transfer spectra of some square-planar complexes of rhodium(I) and iridium(I)
Design and Testing of a Pilot-Scale Aqueous Ammonia Soaking Biomass Pretreatment System
Scale-up of the aqueous ammonia soaking (AAS) biomass pretreatment method to 75-L soaking vessel size was accomplished in this work. A novel, pilot-scale AAS system capable of pretreating 4 kg of switchgrass per cycle was designed, fabricated, and tested. The pretreatment process involved soaking biomass in 29.5% aqueous ammonium hydroxide at a liquid: solid ratio of 5 L/kg. Major vessel design criteria included (1) allowing thorough washing of the soaked biomass in the pretreatment reactor; (2) simple, low-cost fabrication; and (3) limiting safety hazards by minimizing ammonia fumes from the system. Based on these constraints, commercially available 75-L HDPE tanks were selected as the primary vessels for pretreatment. The pretreatments were conducted outside, without agitation during the summer months in Iowa, with ambient temperatures ranging from 15°C to 33°C. During the first experimental cycle, clogging of the outlet resulted in leakage from the vessel during rinsing, and led to redesign of the washout prevention system. The redesigned system used a "teabag" approach in which dry biomass was preloaded into a cylindrical mesh bag, and the filled bag was placed into the soaking vessel. This modification eliminated outlet clogging, simplified biomass loading and unloading, but slightly reduced washing efficiency. Through five soaking cycles, an average of 22% to 25% delignification was achieved (Klason lignin basis) compared to the 35% removal seen at the bench-scale as reported by our group. Approximately 50% to 60% of the pretreated switchgrass was recovered, dry basis, compared to 75% previously achieved at the bench-scale. Overall, the system successfully generated moderate quantities (10 kg/wk) of pretreated biomass for pilot-scale fermentation experiments while illustrating some of the materials handling challenges that must be addressed as pretreatment methods are scaled-up.This article is from Applied Engineering in Agriculture, 25, no. 6 (2009): 953–959.</p
- …