How can we improve management of syncope in the Emergency Department?

Syncope is a common and challenging presenting complaint to the Emergency Department (ED). Despite substantial research efforts, there is still considerable uncertainty about the optimal ED management of syncope. There is continued interest among clinicians and researchers in improving diagnostic algorithms and optimizing resource utilization. In this paper, we discuss 4 strategies to improve the emergency care of syncope patients: (1) Development of accurate and consistent risk-stratification, (2) Increased use of syncope observation protocols, (3) Evaluation of a discharge with ambulatory monitoring pathway, (4) Use of shared decision-making for disposition decisions. Since current risk-stratification tools have fallen short with regard to subsequent validation and implementation into clinical practice, we outline key factors for future risk-stratification research. We propose that observation units have the potential to safely decrease length-of-stay and hospital costs for hemodynamically stable, intermediate risk patients without adversely affecting clinical outcomes. For appropriate patients with a negative ED evaluation, we recommend consideration of direct discharge, with ambulatory monitoring and expedited follow-up, as a means of decreasing costs and reducing iatrogenic harms. Finally, we advocate for the use of shared decision-making regarding the ultimate disposition of select, intermediate risk patients who have not had a serious condition revealed in the ED. If properly implemented, these four strategies could significantly improve the care of ED syncope patients by helping clinicians identify truly high-risk patients, decreasing unnecessary hospitalizations, and increasing patient satisfaction.

Polar Substituents Enable Efficient Catalysis for a Class of Cobalt Polypyridyl Hydrogen Evolving Catalysts

A series of structurally related, acyclic cobalt tetrapyridyl hydrogen evolving catalysts (HEC) were prepared and characterized. The common motif, di(2,2′-bipyridin-6-yl)-methane, was derivatized at the bridging methylene to include a carbonyl group (L1), a hydroxy (L2), a methyl and a hydroxy (L3), a 1,1′-biphenyl-2,2′-diyl (L4), a hydroxy and a phenyl (L5) or a hydroxy and a pyrid-6-yl group. These catalysts were compared with the known HEC [Co(appy)Br]Br. Photo- and electrochemistry showed a distinct influence of the bridging position on rates and stabilities of the hydrogen evolution reaction (HER). Apolar ligands resulted in inferior catalytic performance as compared to HECs with polar substituents. Electrochemically, [Co(L1)Br2] was shown to be converted to [Co(L2)Br2] in catalysis. The best catalyst made more than 10’000 turnovers, albeit at an overpotential of 600 mV. Additional pH dependent mechanistic aspects were elucidated by cyclic voltammetry

High resolution MRI for quantitative assessment of inferior alveolar nerve impairment in course of mandible fractures: an imaging feasibility study

The purpose of this study was to evaluate a magnetic resonance imaging (MRI) protocol for direct visualization of the inferior alveolar nerve in the setting of mandibular fractures. Fifteen patients suffering from unilateral mandible fractures involving the inferior alveolar nerve (15 affected IAN and 15 unaffected IAN from contralateral side) were examined on a 3 T scanner (Elition, Philips Healthcare, Best, the Netherlands) and compared with 15 healthy volunteers (30 IAN in total). The sequence protocol consisted of a 3D STIR, 3D DESS and 3D T1 FFE sequence. Apparent nerve-muscle contrast-to-noise ratio (aNMCNR), apparent signal-to-noise ratio (aSNR), nerve diameter and fracture dislocation were evaluated by two radiologists and correlated with nerve impairment. Furthermore, dislocation as depicted by MRI was compared to computed tomography (CT) images. Patients with clinically evident nerve impairment showed a significant increase of aNMCNR, aSNR and nerve diameter compared to healthy controls and to the contralateral side (p < 0.05). Furthermore, the T1 FFE sequence allowed dislocation depiction comparable to CT. This prospective study provides a rapid imaging protocol using the 3D STIR and 3D T1 FFE sequence that can directly assess both mandible fractures and IAN damage. In patients with hypoesthesia following mandibular fractures, increased aNMCN R, aSNR and nerve diameter on MRI imaging may help identify patients with a risk of prolonged or permanent hypoesthesia at an early time

Two Novel Dinuclear Cobalt Polypyridyl Complexes in Electro- and Photocatalysis for Hydrogen Production: Cooperativity Increases Performance

Syntheses and mechanisms of two dinuclear Co-polypyridyl catalysts for the H2 evolution reaction (HER) were reported and compared to their mononuclear analogue (R1). In both catalysts, two di-(2,2’-bipyridin-6-yl)-methanone units were linked by either 2,2’-bipyridin-6,6’-yl or pyrazin-2,5-yl. Complexation with CoII gave dinuclear compounds bridged by pyrazine (C2) or bipyridine (C1). Photocatalytic HER gave turnover numbers (TONs) of up to 20000 (C2) and 7000 (C1) in water. Electrochemically, C1 was similar to the R1, whereas C2 showed electronic coupling between the two Co centers. The E(CoII/I) split by 360 mV into two separate waves. Proton reduction in DMF was investigated for R1 with [HNEt3](BF4) by simulation, foot of the wave analysis, and linear sweep voltammetry (LSV) with in-line detection of H2. All methods agreed well with an (E)ECEC mechanism and the first protonation being rate limiting (≈104 m−1 s−1). The second reduction was more anodic than the first one. pKa values of around 10 and 7.5 were found for the two protonations. LSV analysis with H2 detection for all catalysts and acids with different pKa values [HBF4, pKa(DMF)≈3.4], intermediate {[HNEt3](BF4), pKa(DMF)≈9.2} to weak [AcOH, pKa(DMF)≈13.5] confirmed electrochemical H2 production, distinctly dependent on the pKa values. Only HBF4 protonated CoI intermediates. The two metals in the dualcore C2 cooperated with an increase in rate to a competitive 105 m−1 s−1 with [HNEt3](BF4). The overpotential decreased compared to R1 by 100 mV. Chronoamperometry established high stabilities for all catalysts with TONlim of 100 for R1 and 320 for C1 and C2

Bacterial populations in different parts of domestic drinking water systems are distinct and adapted to the given ambient temperatures

Drinking water enters buildings with a given microbiological community composition. Within premise plumbing systems, the drinking water is subject to very different conditions and temperatures. Whereas part of the water stays cold, another part is heated to provide hot water. In this study, drinking water samples were taken at different locations in four buildings that had central heating circles and that were equipped with ultrafiltration modules. The latter were intended to keep bacterial numbers low. When studying the increase in bacterial concentrations in these water samples using regrowth tests at different incubation temperatures, a temperature-dependence could be observed. Bacteria in cold water samples propagated best when incubated at 22°C, but often poorly at 36°C and not at all at 50°C. Bacteria in hot water samples showed the reverse behavior and grew best when incubated at 50°C, whereas growth at 22°C was poor or associated with a long growth lag. Water samples from distal taps in periphery locations used for retrieving both cold and hot water showed intermediate growth behaviors. Results suggest the existence of different temperature-adapted bacterial populations within domestic drinking water systems. The finding was supported by sequence data revealing distinct differences in the microbiomes between cold and hot water samples. Abundant bacterial groups in hot water included Deinococci, Kryptonia, Ignavibacteria, Nitrospiria, Gemmatimonadetes and different genera of Gammaproteobacteria. Stagnation of hot water at 50°C, 55°C, or 60°C furthermore shaped the microbiome in different ways indicating that small temperature differences can have a substantial impact on the bacterial communities

Using Feedback Control of Microflows to Independently Steer Multiple Particles

In this paper, we show how to combine microfluidics and feedback control to independently steer multiple particles with micrometer accuracy in two spatial dimensions. The particles are steered by creating a fluid flow that carries all the particles from where they are to where they should be at each time step. Our control loop comprises sensing, computation, and actuation to steer particles along user-input trajectories. Particle locations are identified in real-time by an optical system and transferred to a control algorithm that then determines the electrode voltages necessary to create a flow field to carry all the particles to their next desired locations. The process repeats at the next time instant. Our method achieves inexpensive steering of particles by using conventional electroosmotic actuation in microfluidic channels. This type of particle steering does not require optical traps and can noninvasively steer neutral or charged particles and objects that cannot be captured by laser tweezers. (Laser tweezers cannot steer reflective particles, or particles where the index of refraction is lower than (or for more sophisticated optical vortex holographic tweezers does not differ substantially from) that of the surrounding medium.)We show proof-of-concept PDMS devices, having four and eightelectrodes, with control algorithms that can steer one and three particles, respectively. In particular, we demonstrate experimentally that it is possible to use electroosmotic flow to accurately steer and trap multiple particles at once

Agl24 is an ancient archaeal homolog of the eukaryotic N-glycan chitobiose synthesis enzymes

Protein N-glycosylation is a post-translational modification found in organisms of all domains of life. The crenarchaeal N-glycosylation begins with the synthesis of a lipid-linked chitobiose core structure, identical to that in Eukaryotes, although the enzyme catalyzing this reaction remains unknown. Here, we report the identification of a thermostable archaeal β-1,4-N-acetylglucosaminyltransferase, named archaeal glycosylation enzyme 24 (Agl24), responsible for the synthesis of the N-glycan chitobiose core. Biochemical characterization confirmed its function as an inverting β-D-GlcNAc-(1→4)-α-D-GlcNAc-diphosphodolichol glycosyltransferase. Substitution of a conserved histidine residue, found also in the eukaryotic and bacterial homologs, demonstrated its functional importance for Agl24. Furthermore, bioinformatics and structural modeling revealed similarities of Agl24 to the eukaryotic Alg14/13 and a distant relation to the bacterial MurG, which are catalyzing the same or a similar reaction, respectively. Phylogenetic analysis of Alg14/13 homologs indicates that they are ancient in Eukaryotes, either as a lateral transfer or inherited through eukaryogenesis.</p

How aerogel additives can significantly improve the casting process in foundry applications

Cavities in castings of metals and alloys are obtained by so-called cores, which are made of polymeric-bonded sands. Special additives are used to overcome negative effects that cause a lot of casting defects. Organic resorcinol-formaldehyde (RF) or inorganic carbon aerogel in granular form can replace conventional additives without any effort in the foundry process and offer a variety of advantages due to their nanostructure and composition. We established a synthesis of these aerogel additives for iron casting, transferring the production from laboratory to pilot plant scale, elevating the level of development with respect to foundry needs. Our approach yields about 15 kilogram of RF aerogel in one batch. Further processing includes coarse milling, screening and carbonization of the organic aerogel to amorphous, nanostructured, highly porous carbon with special features. Practical applicability of the additives has been tested and examined in a demanding case of iron casting. We were able to identify some very positive effects of the aerogel additive to the casting process compared to the regular used additive: higher core strength, delayed evolution of gas due to decomposition of the binder, significant reduction of gas emissions (BTXE, phenol, formaldehyde), smooth surface. Additionally, the results show, that a considerable improvement of energy efficiency at different stages of the foundry process can be achieved by the application of aerogel additives