Wider perioperative glycemic fluctuations increase risk of postoperative atrial fibrillation and ICU length of stay

<div><p>Introduction</p><p>Postoperative atrial fibrillation (POAF) is a common complication following cardiac surgery associated with increased morbidity and mortality. Although sustained hyperglycemia is a known risk factor of AF and poor ICU outcomes, emerging in-vitro studies reveal acute glycemic fluctuations to be an additional independent predictor of AF. The effect of acute glycemic fluctuations on the incidence of POAF in the clinical setting remains unclear. We aim to investigate the effect of the magnitude of acute perioperative glycemic fluctuations on the incidence of POAF in a multi-ethnic Southeast-Asian population.</p><p>Methods</p><p>We obtained data from1743 patients who underwent elective CABG in a tertiary heart centre from 2009–2011. Patients were kept to a tight baseline glycemic control in accordance with hospital protocol. The magnitude of the difference between the highest and lowest perioperative glucose levels up till the first 48 postoperative hours was employed as a measure of glycemic fluctuation. Patients were divided into 4 groups for analysis based on the magnitude of glycemic fluctuation:A)0-2mmol/L(N = 147); B)>2-4mmol/L(N = 426); C)>4-6mmol/L(N = 513); D)>6mmol/L(N = 657).Our primary outcome was the incidence of POAF. Secondary outcomes included ICU and 30-day mortality and length of stay.</p><p>Results</p><p>The overall incidence of POAF was 14.7%. This increased as the magnitude of glycemic fluctuation increased, and was statistically highest in Group D(16.4%) as compared with the other 3 sub-groups. Multivariate logistic regression revealed the magnitude of perioperative glycemic fluctuation to be an independent risk factor of POAF(O.R.1.06, 95% C.I.1.01–1.11, p = 0.014).ICU length of stay was statistically highest in Group D(63.1 hours, p = < .001). However, ICU and 30 day mortality rates were similar among the 4 groups.</p><p>Conclusion</p><p>Increased magnitudes of acute perioperative glycemic fluctuations are associated with a significantly increased risk of POAF and length of ICU stay; and should therefore be minimised but balanced against the risks of hypoglycemia so as to avoid POAF and optimise patient outcomes.</p></div

Significant risk factors of postoperative atriai fibrillation on multivariate logistic regression.

<p>Significant risk factors of postoperative atriai fibrillation on multivariate logistic regression.</p

Secondary outcomes among 4 glycemic sub-groups.

<p>Secondary outcomes among 4 glycemic sub-groups.</p

Perioperative glycemic fluctuation and postoperative AF.

<p>Perioperative glycemic fluctuation and postoperative AF.</p

Autumn NDVI contributes more and more to vegetation improvement in the growing season across the Tibetan Plateau

<p>Detecting changes in vegetation, distinguishing the persistence of changes, and seeking their causes during multiple periods are important to gaining a deeper understanding of vegetation dynamics. Using the Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index (NDVI) version NDVI_3g dataset in the Tibetan Plateau, the trends in the seasonal components of NDVI and their linkage with climatic factors were analyzed over 14 asymptotic periods of 18–31 years since 1982. Dynamic trends in vegetation experienced an obvious increase at regional scale, but the increases of vegetation activity mostly tended to stall or slow down as the studied time period was extended. At pixel scale, areas with significant browning significantly expanded over 14 periods for all seasons, but for significant greening significantly increased only in autumn. The changes of vegetation activity in spring were the most drastic among three seasons. Increased increments of NDVI in summer, spring, and autumn took turns being the main reason for the enhanced vegetation activity in the growing season in the nested 14 periods. Vegetation activity was mainly regulated by a thermal factor, and the dominant climatic drivers of vegetation growth varied across different seasons and regions. We speculate that the increase of NDVI will continue but the increments will decline in all seasons except autumn.</p

Integrated Charge Transfer in Colloidal Cu–MnO Heterostructures for High-Performance Lithium Ion Batteries

Nanodimensional monodispersed Cu–MnO heterostructures were synthesized via a facile solution-based method. Cu–MnO heterostructures with narrow size distribution were successfully achieved in the presence of organic surfactants to prevent agglomeration during the growth process. Furthermore, the unique architecture of carbon-coated Cu–MnO (Cu–MnO@C) core–shell heterostructures obtained after a thermal annealing process preserved the electrical integrity of the electrode via the conductive copper “nanobridge” to provide an efficient electron transfer pathway between the active materials and the current collector. On the other hand, the amorphous carbonaceous shell evidently gives a protective layer to attain structural integrity throughout the electrochemical measurements. Enhancement in the electrochemical performance can be reflected by the excellent cycling stability and high rate capability of the Cu–MnO@C heterostructures as compared to the MnO@C nanoparticles

Aqueous-Based Chemical Route toward Ambient Preparation of Multicomponent Core–Shell Nanotubes

Room-temperature synthesized V₂O₅@MnO₂ core–shell nanotubes with tunable tunnel dimensions <i>via</i> a facile aqueous-based method are presented. The rational-designed tubular morphology endows them with good permeability of electrolyte ions for maximum utilization of the electroactive sites, while the epitaxial-grown MnO₂ imposes mechanical support to V₂O₅ against structural collapse upon long-term cycling. Hence, specific capacitance as high as 694 F g^–1 is achieved at 1 A g^–1 accompanied by excellent cycling stability (preserved 92% of its initial specific capacitance after 5000 cycles). In addition, functionalization of the V₂O₅@MnO₂ nanotubes with other transition metal oxides results in ternary composites, V₂O₅@MnO₂/M nanotubes (M = Fe₂O₃, Co₂O₃/Co(OH)₂, Ni(OH)₂). The versatility of this synthetic protocol provides a platform to fabricate complex ternary nanocomposites in a more benign way

General Approach for MOF-Derived Porous Spinel AFe₂O₄ Hollow Structures and Their Superior Lithium Storage Properties

A general and simple approach for large-scale synthesis of porous hollow spinel AFe₂O₄ nanoarchitectures via metal organic framework self-sacrificial template strategy is proposed. By employing this method, we can successfully synthesize uniform NiFe₂O₄, ZnFe₂O₄, and CoFe₂O₄ hollow architectures that are hierarchically assembled by nanoparticles. When these hollow microcubes were tested as anode for lithium ion batteries, good rate capability and long-term cycling stability can be achieved. For example, high specific capacities of 636, 449, and 380 mA h g^–1 were depicted by NiFe₂O₄, ZnFe₂O₄, and CoFe₂O₄, respectively, at a high current density of 8.0 A g^–1. NiFe₂O₄ exhibits high specific capacities of 841 and 447 mA h g^–1 during the 100th cycle when it was tested at current densities of 1.0 and 5.0 A g^–1, respectively. Discharge capacities of 390 and 290 mA h g^–1 were delivered by the ZnFe₂O₄ and CoFe₂O₄, respectively, during the 100th cycle at 5.0 A g^–1

Controlled Soft-Template Synthesis of Ultrathin C@FeS Nanosheets with High-Li-Storage Performance

We report a facile approach to prepare carbon-coated troilite FeS (C@FeS) nanosheets <i>via</i> surfactant-assisted solution-based synthesis. 1-Dodecanethiol is used as both the sulfur source and the surfactant, which may form different-shaped micelles to direct the growth of nanostructures. Under appropriate growth conditions, the iron and sulfur atoms react to form thin layers of FeS while the hydrocarbon tails of 1-dodecanethiol separate the thin FeS layers, which turn to carbon after annealing in Ar. Such an approach can be extended to grow C@FeS nanospheres and nanoplates by modifying the synthesis parameters. The C@FeS nanosheets display excellent Li storage properties with high specific capacities and stable charge/discharge cyclability, especially at fast charge/discharge rates

Fe-Based Metallopolymer Nanowall-Based Composites for Li–O₂ Battery Cathode

Metallopolymer nanowalls were prepared through a simple wet-chemical process using reduced graphene oxides as heterogeneous nucleation aids, which also help to form conductive electron paths. The nanowalls grow vertically on graphene surface with 100 -200 nm in widths and ∼20 nm in thickness. The Fe-based metallopolymer nanowall-based electrode shows best performance as O₂ cathode exhibiting high round-trip efficiencies and stable cycling performance among other transition metal containing metallopolymer counterparts. The electrode delivers discharge–charge capacities of 1000 mAh/g for 40 cycles and maintains round-trip efficiencies >78 % at 50 mA/g. The 1^st-cycle round-trip efficiencies are 79%, 72%, and 65% at current densities of 50, 200, and 400 mA/g, respectively. The NMR analysis of the Fe-based metallopolymer based electrode after 40 cycles reveals slow formation of the side products, CH₃CO₂Li and HCO₂Li