Smoking and home oxygen therapy: a review and consensus statement from a multidisciplinary Swedish taskforce.

BACKGROUND: Home oxygen therapy (HOT) improves survival in patients with hypoxaemic chronic respiratory disease. Most patients evaluated for HOT are former or active smokers. Oxygen accelerates combustion and smoking may increase the risk of burn injuries and fire hazards; therefore, it is considered a contraindication for HOT in many countries. However, there is variability in the practices and policies regarding this matter. This multidisciplinary Swedish taskforce aimed to review the potential benefits and risks of smoking in relation to HOT, including medical, practical, legal and ethical considerations. METHODS: The taskforce of the Swedish Respiratory Society comprises 15 members across respiratory medicine, nursing, medical law and ethics. HOT effectiveness and adverse risks related to smoking, as well as practical, legal and ethical considerations, were reviewed, resulting in five general questions and four PICO (population-intervention-comparator-outcome) questions. The strength of each recommendation was rated according to the GRADE (grading of recommendation assessment, development and evaluation) methodology. RESULTS: General questions about the practical, legal and ethical aspects of HOT were discussed and summarised in the document. The PICO questions resulted in recommendations about assessment, management and follow-up of smoking when considering HOT, if HOT should be offered to people that meet the eligibility criteria but who continue to smoke, if a specific length of time of smoking cessation should be considered before assessing eligibility for HOT, and identification of areas for further research. CONCLUSIONS: Multiple factors need to be considered in the benefit/risk evaluation of HOT in active smokers. A systematic approach is suggested to guide healthcare professionals in evaluating HOT in relation to smoking.

On the Stability of NaO2 in Na-O2 Batteries.

Na-O2 batteries are regarded as promising candidates for energy storage. They have higher energy efficiency, rate capability, and chemical reversibility than Li-O2 batteries; in addition, sodium is cheaper and more abundant compared to lithium. However, inconsistent observations and instability of discharge products have inhibited the understanding of the working mechanism of this technology. In this work, we have investigated a number of factors that influence the stability of the discharge products. By means of in operando powder X-ray diffraction study, the influence of oxygen, sodium anode, salt, solvent, and carbon cathode were investigated. The Na metal anode and an ether-based solvent are the main factors that lead to the instability and decomposition of NaO2 in the cell environment. This fundamental insight brings new information on the working mechanism of Na-O2 batteries.

Towards an Understanding of Li2 O2 Evolution in Li-O2 Batteries: An In†Operando Synchrotron X-ray Diffraction Study.

One of the major challenges in developing high-performance Li-O2 batteries is to understand the Li2 O2 formation and decomposition during battery cycling. In this study, this issue was investigated by synchrotron radiation powder X-ray diffraction. The evolution of Li2 O2 morphology and structure was observed under actual electrochemical conditions of battery operation. By quantitatively tracking Li2 O2 during discharge and charge, a two-step process was suggested for both growth and oxidation of Li2 O2 owing to different mechanisms during two stages of both oxygen reduction reaction and oxygen evolution reaction. From an observation of the anisotropic broadening of Li2 O2 in XRD patterns, it was inferred that disc-like Li2 O2 grains are formed rapidly in the first step of discharge. These grains can stack together so that they facilitate the nucleation and growth of toroidal Li2 O2 particles with a LiO2 -like surface, which could cause parasitic reactions and hinder the formation of Li2 O2 . During the charge process, Li2 O2 is firstly oxidized from the surface, followed by a delithiation process with a faster oxidation of the bulk by stripping the interlayer Li atoms to form an off-stoichiometric intermediate. This fundamental insight brings new information on the working mechanism of Li-O2 batteries.

Structure Characterization and Properties of K-Containing Copper Hexacyanoferrate.

Copper hexacyanoferrate, Cu(II)[Fe(III)(CN)6]2/3·nH2O, was synthesized, and varied amounts of K(+) ions were inserted via reduction by K2S2O3 (aq). Ideally, the reaction can be written as Cu(II)[Fe(III)(CN)6]2/3·nH2O + 2x/3K(+) + 2x/3e(-) ↔ K2x/3Cu(II)[Fe(II)xFe(III)1-x(CN)6]2/3·nH2O. Infrared, Raman, and Mössbauer spectroscopy studies show that Fe(III) is continuously reduced to Fe(II) with increasing x, accompanied by a decrease of the a-axis of the cubic Fm3̅m unit cell. Elemental analysis of K by inductively coupled plasma shows that the insertion only begins when a significant fraction, ∼20% of the Fe(III), has already been reduced. Thermogravimetric analysis shows a fast exchange of water with ambient atmosphere and a total weight loss of ∼26 wt % upon heating to 180 °C, above which the structure starts to decompose. The crystal structures of Cu(II)[Fe(III)(CN)6]2/3·nH2O and K2/3Cu[Fe(CN)6]2/3·nH2O were refined using synchrotron X-ray powder diffraction data. In both, one-third of the Fe(CN)6 groups are vacant, and the octahedron around Cu(II) is completed by water molecules. In the two structures, difference Fourier maps reveal three additional zeolitic water sites (8c, 32f, and 48g) in the center of the cavities formed by the -Cu-N-C-Fe- framework. The K-containing compound shows an increased electron density at two of these sites (32f and 48g), indicating them to be the preferred positions for the K(+) ions.

SEI Formation and Interfacial Stability of a Si Electrode in a LiTDI-Salt Based Electrolyte with FEC and VC Additives for Li-Ion Batteries.

An electrolyte based on the new salt, lithium 4,5-dicyano-2-(trifluoromethyl)imidazolide (LiTDI), is evaluated in combination with nano-Si composite electrodes for potential use in Li-ion batteries. The additives fluoroethylene carbonate (FEC) and vinylene carbonate (VC) are also added to the electrolyte to enable an efficient SEI formation. By employing hard X-ray photoelectron spectroscopy (HAXPES), the SEI formation and the development of the active material is probed during the first 100 cycles. With this electrolyte formulation, the Si electrode can cycle at 1200 mAh g(-1) for more than 100 cycles at a coulombic efficiency of 99%. With extended cycling, a decrease in Si particle size is observed as well as an increase in silicon oxide amount. As opposed to LiPF6 based electrolytes, this electrolyte or its decomposition products has no side reactions with the active Si material. The present results further acknowledge the positive effects of SEI forming additives. It is suggested that polycarbonates and a high LiF content are favorable components in the SEI over other kinds of carbonates formed by ethylene carbonate (EC) and dimethyl carbonate (DMC) decomposition. This work thus confirms that LiTDI in combination with the investigated additives is a promising salt for Si electrodes in future Li-ion batteries.

Erratum: Superficial vessel reconstruction with a Multiview camera system.

[This corrects the article DOI: 10.1117/1.JMI.3.1.015001.].

Superficial vessel reconstruction with a multiview camera system.

We aim at reconstructing superficial vessels of the brain. Ultimately, they will serve to guide the deformation methods to compensate for the brain shift. A pipeline for three-dimensional (3-D) vessel reconstruction using three mono-complementary metal-oxide semiconductor cameras has been developed. Vessel centerlines are manually selected in the images. Using the properties of the Hessian matrix, the centerline points are assigned direction information. For correspondence matching, a combination of methods was used. The process starts with epipolar and spatial coherence constraints (geometrical constraints), followed by relaxation labeling and an iterative filtering where the 3-D points are compared to surfaces obtained using the thin-plate spline with decreasing relaxation parameter. Finally, the points are shifted to their local centroid position. Evaluation in virtual, phantom, and experimental images, including intraoperative data from patient experiments, shows that, with appropriate camera positions, the error estimates (root-mean square error and mean error) are [Formula: see text].

Passivation Layer and Cathodic Redox Reactions in Sodium-Ion Batteries Probed by HAXPES.

The cathode material P2-Nax Co2/3 Mn2/9 Ni1/9 O2, which could be used in Na-ion batteries, was investigated through synchrotron-based hard X-ray photoelectron spectroscopy (HAXPES). Nondestructive analysis was made through the electrode/electrolyte interface of the first electrochemical cycle to ensure access to information not only on the active material, but also on the passivation layer formed at the electrode surface and referred to as the solid permeable interface (SPI). This investigation clearly shows the role of the SPI and the complexity of the redox reactions. Cobalt, nickel, and manganese are all electrochemically active upon cycling between 4.5 and 2.0 V; all are in the 4+ state at the end of charging. Reduction to Co(3+), Ni(3+), and Mn(3+) occurs upon discharging and, at low potential, there is partial reversible reduction to Co(2+) and Ni(2+). A thin layer of Na2 CO3 and NaF covers the pristine electrode and reversible dissolution/reformation of these compounds is observed during the first cycle. The salt degradation products in the SPI show a dependence on potential. Phosphates mainly form at the end of the charging cycle (4.5 V), whereas fluorophosphates are produced at the end of discharging (2.0 V).

Recycled Poly(vinyl alcohol) Sponge for Carbon Encapsulation of Size-Tunable Tin Dioxide Nanocrystalline Composites.

The recycling of industrial materials could reduce their environmental impact and waste haulage fees and result in sustainable manufacturing. In this work, commercial poly(vinyl alcohol) (PVA) sponges are recycled into a macroporous carbon matrix to encapsulate size-tunable SnO2 nanocrystals as anode materials for lithium-ion batteries (LIBs) through a scalable, flash-combustion method. The hydroxyl groups present copiously in the recycled PVA sponges guarantee a uniform chemical coupling with a tin(IV) citrate complex through intermolecular hydrogen bonds. Then, a scalable, ultrafast combustion process (30 s) carbonizes the PVA sponge into a 3D carbon matrix. This PVA-sponge-derived carbon could not only buffer the volume fluctuations upon the Li-Sn alloying and dealloying processes but also afford a mixed conductive network, that is, a continuous carbon framework for electrical transport and macropores for facile electrolyte percolation. The best-performing electrode based on this composite delivers a rate performance up to 9.72 C (4 A g(-1) ) and long-term cyclability (500 cycles) for Li(+) ion storage. Moreover, cyclic voltammograms demonstrate the coexistence of alloying and dealloying processes and non-diffusion-controlled pseudocapacitive behavior, which collectively contribute to the high-rate Li(+) ion storage.

An Organic Catalyst for Li-O2 Batteries: Dilithium Quinone-1,4-Dicarboxylate.

Solid organic electrocatalysts have hardly been tested in Li-O2 batteries. Here, a new solid organic electrocatalyst, dilithium quinone-1,4-dicarboxylate (Li2 C8 H2 O6 ) is presented, which is expected to overcome the shortcomings of inorganic catalysts. The function-oriented synthesis is low cost and low polluting. The electrocatalytic performance is evaluated by following the degradation of Li2 O2 during the charge process in a Li-O2 cell through in situ XRD and operando synchrotron radiation powder XRD (SR-PXD) measurements. The results indicate that the electrocatalytic activity of Li2 C8 H2 O6 is similar to that of commercial Pt. The Li2 O2 decomposition in a cell with Li2 C8 H2 O6 catalyst follows a pseudo-zero-order reaction, virtually without any side reactions. These results provide an insight into the development of new organic catalysts for the oxygen evolution reaction (OER) in Li-O2 batteries.

A high pressure x-ray photoelectron spectroscopy experimental method for characterization of solid-liquid interfaces demonstrated with a Li-ion battery system.

We report a methodology for a direct investigation of the solid/liquid interface using high pressure x-ray photoelectron spectroscopy (HPXPS). The technique was demonstrated with an electrochemical system represented by a Li-ion battery using a silicon electrode and a liquid electrolyte of LiClO4 in propylene carbonate (PC) cycled versus metallic lithium. For the first time the presence of a liquid electrolyte was realized using a transfer procedure where the sample was introduced into a 2 mbar N2 environment in the analysis chamber without an intermediate ultrahigh vacuum (UHV) step in the load lock. The procedure was characterized in detail concerning lateral drop gradients as well as stability of measurement conditions over time. The X-ray photoelectron spectroscopy (XPS) measurements demonstrate that the solid substrate and the liquid electrolyte can be observed simultaneously. The results show that the solid electrolyte interphase (SEI) composition for the wet electrode is stable within the probing time and generally agrees well with traditional UHV studies. Since the methodology can easily be adjusted to various high pressure photoelectron spectroscopy systems, extending the approach towards operando solid/liquid interface studies using liquid electrolytes seems now feasible.

Improving the electrochemical performance of organic Li-ion battery electrodes.

Dilithium benzenediacrylate was prepared and investigated as an example of a readily available organic electrode material for lithium-ion batteries. Its poor conductive properties were overcome by a method of carbon-coating in the liquid state, resulting in enhanced cycling performance, displaying a reversible capacity of 180 mA h g(-1).

Real-time intraoperative visualization of myocardial circulation using augmented reality temperature display.

For direct visualization of myocardial ischemia during cardiac surgery, we tested the feasibility of presenting infrared (IR) tissue temperature maps in situ during surgery. A new augmented reality (AR) system, consisting of an IR camera and an integrated projector having identical optical axes, was used, with a high resolution IR camera as control. The hearts of five pigs were exposed and an elastic band placed around the middle of the left anterior descending coronary artery to induce ischemia. A proximally placed ultrasound Doppler probe confirmed reduction of flow. Two periods of complete ischemia and reperfusion were studied in each heart. There was a significant decrease in IR-measured temperature distal to the occlusion, with subsequent return to baseline temperatures after reperfusion (baseline 36.9 ± 0.60 (mean ± SD) versus ischemia 34.1 ± 1.66 versus reperfusion 37.4 ± 0.48; p < 0.001), with no differences occurring in the non-occluded area. The AR presentation was clear and dynamic without delay, visualizing the temperature changes produced by manipulation of the coronary blood flow, and showed concentrically arranged penumbra zones during ischemia. Surface myocardial temperature changes could be assessed quantitatively and visualized in situ during ischemia and subsequent reperfusion. This method shows potential as a rapid and simple way of following myocardial perfusion during cardiac surgery. The dynamics in the penumbra zone could potentially be used for visualizing the effect of therapy on intraoperative ischemia during cardiac surgery.

Self-supported three-dimensional nanoelectrodes for microbattery applications.

A nanostructured three-dimensional (3D) microbattery has been produced and cycled in a Li-ion battery. It consists of a current collector of aluminum nanorods, a uniform layer of 17 nm TiO(2) covering the nanorods made using ALD, an electrolyte and metallic lithium counter electrode. The battery is electrochemically cycled more than 50 times. The increase in total capacity is 10 times when using a 3D architecture compared to a 2D system for the same footprint area.

Lithium vanadate Li(3+x)V6O13 at low temperature.

The structure of Li(3+x)V6O13 [x = 0.24 (3)] at 95 K has been solved and refined using single-crystal X-ray diffraction. The refined lithium content corresponds to two fully occupied Li sites and one partially occupied Li site. A doubling of the c axis is observed upon cooling from room temperature, and this change is associated with shifts of the V atoms. The resulting space group is C2/c. The Li disorder present in the Li3V6O13 phase at room temperature is also observed in the low-temperature phase reported here.

Li(3+delta)V6O13: a short-range-ordered lithium insertion mechanism.

The structures of Li3V6O13 and Li(3+delta)V6O13, delta approximately 0.3, have been determined by single-crystal X-ray diffraction. Both compounds have the space group C2/m, with very similar cell parameters. In Li3V6O13, the Li atoms are found in the Wyckoff positions 4(i) and 2(b) with multiplicities of four and two, respectively. Since Li3V6O13 exhibits no superstructure reflections, it is concluded that Li3V6O13 contains one disordered lithium ion in an otherwise ordered centrosymmetric structure. On inserting more lithium into the structure, the Li(3+delta)V6O13 phase is formed with the homogeneity range 0 < delta < 1. It is concluded that the site for the extra inserted lithium ion is closely coupled to the position of the disordered lithium ion in Li3V6O13. A mechanism for this behaviour and for the further formation of the Li6V6O13 end-phase in the LixV6O13 system is proposed.

Low-temperature structure of V6O13.

The structure of the transition metal oxide V6O13, a potential cathode material in lithium-polymer batteries, has been studied at 95 K using single-crystal X-ray diffraction (XRD). A phase transition has been determined by differential scanning calorimetry (DSC) measurements to occur at 153 K, with a heat of transition of -1.98 kJ mol(-1). In this low-temperature phase, the V and O atoms move by up to 0.21 A out of the mirror plane they occupy in the room-temperature structure. It is concluded that the earlier reported space group P2(1)/a [Kawada et al. (1978). Acta Cryst. B34, 1037-1039] is incorrect and that a more appropriate choice of space group is Pc.