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The most promising candidate as an everyday alternative to lithium-ion batteries (LIBs) are sodium-ion batteries (NIBs). This is not only due to Na abundance, but also because the main principles and cell structure are very similar to LIBs. Due to these benefits, NIBs are expected to be used in applications related to large-scale energy storage systems and other applications not requiring top-performance in terms of volumetric capacity. One important issue that has hindered the large scale application of NIBs is the anode material. Graphite and silicon, which have been widely applied as anodes in NIBs, do not show great performance. Hard carbons look very promising in terms of their abundance and low cost, but they tend to suffer from instability, in particular over the long term. In this work we explore a carbon-coated TiO2 nanoparticle system that looks very promising in terms of stability, abundance, low-cost, and most importantly that safety of the cell, since it does not suffer from potential sodium plating during cycling. Maintaining a nano-size and consistent morphology of the active material is a crucial parameter for maintaining a well-functioning cell upon cycling. In this work we applied Anomalous Small Angle X-Ray Scattering (ASAXS) for the first time at the Ti K-edge of TiO2 anatase nanoparticles on different cycled composite electrodes in order to have a complete morphological overview of the modifications induced by sodiation and desodiation. This work also demonstrates for the first time that the nanosize of the TiO2 is maintained upon cycling, which is in agreement with the electrochemical stability.
The transfer of pathogens may spread antimicrobial resistance and lead to healthcare-acquired infections. We performed a systematic literature review to generate estimates of pathogen transfer in relation to healthcare provider (HCP) activities.
For this systematic review and meta-analysis, Medline/Ovid, EMBASE, and the Cochrane Library were searched for studies published before July 7, 2017. We reviewed the literature, examining transfer of pathogens associated with HCP activities. We included studies that (1) quantified transfer of pathogens from a defined origin to a defined destination surface; (2) reported a microbiological sampling technique; and (3) described the associated activity leading to transfer. For studies reporting transfer frequencies, we extracted data and calculated the estimated proportion using Freeman-Tukey double arcsine transformation and the DerSimonian-Laird random-effects model.
Of 13,121 identified articles, 32 were included. Most articles (n=27, 84%) examined transfer from patients and their environment to HCP hands, gloves, and gowns, with an estimated proportion for transfer frequency of 33% (95% confidence interval [CI], 12%–57%), 30% (95% CI, 23%–38%) and 10% (95% CI, 6%–14%), respectively. Other articles addressed transfer involving the hospital environment and medical devices. Risk factor analyses in 12 studies suggested higher transfer frequencies after contact with moist body sites (n=7), longer duration of care (n=5), and care of patients with an invasive device (n=3).
Recognizing the heterogeneity in study designs, the available evidence suggests that pathogen transfer to HCPs occurs frequently. More systematic research is urgently warranted to support targeted and economic prevention policies and interventions.
In this study, we sought to establish a comprehensive inventory of infectious risk moments (IRMs), defined as seemingly innocuous yet frequently occurring care manipulations potentially resulting in transfer of pathogens to patients. We also aimed to develop and employ an observational taxonomy to quantify the frequency and nature of IRMs in acute-care settings.
Prospective observational study and establishment of observational taxonomy.
Intensive care unit, general medical ward, and emergency ward of a university-affiliated hospital.
Healthcare workers (HCWs)
Exploratory observations were conducted to identify IRMs, which were coded based on the surfaces involved in the transmission pathway to establish a structured taxonomy. Structured observations were performed using this taxonomy to quantify IRMs in all 3 settings.
Following 129.17 hours of exploratory observations, identified IRMs involved HCW hands, gloves, care devices, mobile objects, and HCW clothing and accessories. A structured taxonomy called INFORM (INFectiOus Risk Moment) was established to classify each IRM according to the source, vector, and endpoint of potential pathogen transfer. We observed 1,138 IRMs during 53.77 hours of structured observations (31.25 active care hours) for an average foundation of 42.8 IRMs per active care hour overall, and average densities of 34.9, 36.8, and 56.3 IRMs in the intensive care, medical, and emergency wards, respectively.
Hands and gloves remain among the most important contributors to the transfer of pathogens within the healthcare setting, but medical devices, mobile objects, invasive devices, and HCW clothing and accessories may also contribute to patient colonization and/or infection. The INFORM observational taxonomy and IRM inventory presented may benefit clinical risk assessment, training and education, and future research.
To elicit expert consensus on the likelihood of infectious outcomes (patient colonization or infection) following a broad range of infectious risk moments (IRMs) from observations in acute care.
Expert consensus study using modified Delphi technique.
Panel of 40 international experts including nurses, physicians and microbiologists specialized in infectious diseases and infection prevention and control (IPC).
The modified Delphi process consisted of 3 online survey rounds, with feedback of mean ratings and expert comments between rounds. The Delphi survey comprised 52 care scenarios representing observed IRMs organized into 6 sections: hands, gloves, medical devices, mobile objects, invasive procedures, and additional moments. For each scenario, experts indicated the likelihood of both patient colonization and infection on a scale from 0 to 5 (high). Expert ratings were plotted against frequencies of IRMs observed during actual patient care resulting in a risk index.
Following 3 rounds, consensus was achieved for 92 of 104 items (88.5%). The mean ratings across all scenarios for likelihood of colonization and infection were 2.68 and 2.02, respectively. The likelihood of colonization was rated higher than infection for 48 of 52 scenarios. Ratings were significantly higher for colonization (P=.001) and infection (P<.0005) when the scenario involved transfer of pathogens to critical patient sites.
The design of effective IPC strategies requires the selection of behaviors according to their impact on patient outcomes. The IRM index reported here provides a basis for standardizing and prioritizing targets for quality improvement initiatives, training, and future research in acute health care.
The absolute chronology of the Kura-Araxes (KA) culture in the Southern Caucasus still represents a challenge due to the fragmentation and inadequacy of the radiocarbon record, as well as the inconsistencies in material typologies in the region. Recent archaeological fieldwork at the site of Aradetis Orgora in the Shida Kartli region of Georgia revealed four occupation levels dating to the KA II phase according to the local relative chronology. 14C samples were collected from reliable contexts and further selected according to reliability criteria, taking into account both archaeological issues and lab procedures. FTIR was applied in order to determine the preservation of charcoals and to monitor the efficiency of lab treatments on all the samples. Only accurate 14C measurements were selected for Bayesian analysis incorporating stratigraphic information. Two models were run, the second of which simulated intervals corresponding to unexcavated stratigraphy or due to a lack of samples. In this article, the available 14C dates for the KA occupation at Aradetis are presented for the first time and analyzed using Bayesian principles. The results of Bayesian modeling suggest that the occupation of the excavated KA II levels cover the period between 3040–2810 BC (simple model) or 3090–2720 BC (interval model).
Supercapacitors are nowadays considered to be one of the most important electrochemical storage devices. These devices display high power and extraordinary cycle life, and they are currently used in an increasing number of applications. However, in order to further increase the applications of supercapacitors, an increase in their energy capacity appears to be necessary. Moreover, the development of safe and environmentally friendly supercapacitors is also required. In this article, we illustrate the contributions ionic liquids (ILs) might play in the development of high energy and safe supercapacitors. First, the use of ILs as electrolytes in supercapacitors is considered, and the advantages as well as challenges related to the use of this kind of electrolyte are analyzed. Next, the interaction between ILs and electrode materials is taken into account, with particular attention paid to inactive components of supercapacitor electrodes. The introduction of natural cellulose as a binder is used as an example of the contribution ILs might provide to the development of environmentally friendly supercapacitors.
Ionic liquids (ILs) are a very interesting new class of fluid materials because of their unique characteristics, such as wide chemical, thermal, and electrochemical stability, high ion conduction, non-detectable vapor pressure, nonflammability, and good-to-excellent capability to dissolve inorganic, organic, and polymer compounds. ILs are proposed for a very wide variety of applications, including electrochemical devices. However, high purity ILs, particularly for high-energy electrochemical applications, are not widely available commercially. In addition, solvent restriction and environmental impact, as well as the possibility to fully recycle chemicals and reagents, represent the most stringent requirements for the future synthesis processes of ILs. This article reviews synthesis route improvements in terms of environment impact solvents, chemical recycling and cost, and process yield for obtaining high purity (below 50 ppm) ILs.
Detection of linear polarisation at a level of 1 ppm or less, associated to the anisotropy of the cosmic microwave background, will confirm the cosmological origin of the observed anisotropy and provide information on the thermal history of the universe between the recombination epoch and now. In particular, detection of polarisation can help in deciding if the evolution of the universe included a reionisation epoch. We present the Mk3 model of our correlation polarimeter, an improved version of a system which has already been used for observations of the region of sky around the South Celestial Pole from Antarctica (in 1994 at Terra Nova Bay and in 1998 at Dome C).
A progress report of the MASTER project is presented here. MASTER is a system of three heterodyne receivers based on SIS (superconductor–insulator–superconductor) tunnel junction mixers. In our instrument these mixers will allow direct down-conversion from 94, 225, and 345 to 1.5 GHz, the IF where the signal will be detected. This instrument, coupled to a 2–4 m telescope like the one proposed for the DOME C base in Antarctica and in conjunction with an Acusto Optical Spectrometer, can be used to detect emission lines associated with molecular clouds in the interstellar medium. The current status of a 94 GHz receiver, the prototype of MASTER, will be presented too. The study of the optical coupling between the receiver and MITO telescope in the Italian Alps will also be described.
The Milano Polarimeter (MiPol), a correlation system with phase
modulation has been built for the studies of the CMB polarization
at large angular scales. At present the system is at the Testa
Grigia Observatory on the Italian Alps (3480 m asl). We are
ready to bring it to Dome Concordia for observations during the
Antarctic winter beginning in March 2006. We discuss the system
performance, its sensitivity and the status of the searches for
A radiometer based on SIS mixers for astrophysical observations is
being assembled. The system, cooled to cryogenic temperature by a
pulse tube refrigerator, is intended for operation on the Antartic
Plateau during the local winter, using the mm dishes available
there in the future. The system prototype will be tested at the
focus of the 2.6 m MITO telescope at the Testa Grigia Observatory
on the italian Alps. We discuss the system characteristics and the
When this poem was written, Europe was in the midst of a civil war between “hordes of beasts” (the Fascists) on one side and the anti-Fascists on the other, and its fate depended on the outcome of this conflict. The idea of a united Europe had been seized upon by both the Nazis and the Fascists in the period between the two wars, as well as during the war itself. Two examples of this are the Convegno Volta, a conference on Europe organized in 1932 under the auspices of the Fascist regime in Rome and the projects presented by Goebbels and Von Ribbentrop in 1942–3 for a “new Europe” to be united under Nazi dominion. Those who resisted the various types of Fascism and claimed to be “sons” of Europe could count on only a “frail myth”—if I may be allowed to extend Sereni's metaphor—and this myth projected a possible Europe and possible Europeanness into a completely uncertain future. At that time the sense of belonging to Europe was more of a wager than a reference to a given reality.
The tradition of a united Europe was centuries old, but the First World War had reduced it to ashes.
Several iron phosphates were synthesized by solution-based techniques and tested as cathodes in non aqueous lithium cells. The addition of phosphate ions to a solution of iron (II) produced crystalline Fe3(PO4)2. This material is easily oxidized by air to form an amorphous phase that is able to reversibly intercalate lithium. The amorphous compound was identified to be a mixture of FePO4 and Fe2O3. A new synthetic route was developed to prepare pure amorphous FePO4. Amorphous LiFePO4 was obtained by chemical lithiation of FePO4. The material was heated at 500°C under reducing atmosphere to obtain nano-crystalline LiFePO4. This latter material showed excellent electrochemical performance when used as cathode of lithium cells.
Various forms of vanadium pentoxide, including xerogel, aerogel, and aerogel-like forms, were prepared by sol-gel synthesis and processed by novel procedures following synthesis. It was demonstrated that the intrinsic thermodynamics of lithium intercalation of the ARG and ARG-like materials prepared by solvent exchange processes involving methyl formate (MF/ARG and MF/ARG-xslike) are identical, while they are drastically different from those of the parent XRG, which gives rise to significantly increased specific energies for the MF/ARG or MF/ARG-like as lithium intercalation hosts. All three forms are capable of reversibly intercalating up to four moles of Li+ ions per mole of V205 electrochemically and can be cathode candidates for rechargeable lithium batteries. Various processing methods for fabricating composite electrodes with the XRG led to specific capacity in the range of 300 to 350 mAh/g at C4Li/ 20 rate, and good cyclability.
Sol-gel derived amorphous manganese dioxide (a-MnO2) showed extremely high reversible lithium intercalation capacity. The composition and structure of the material were modified by heating at different temperatures. Cycling performance of the modified samples suggests that lowering the water content in the material is beneficial, while introducing crystallinity is detrimental, to its cyclability. A novel double-solvent-exchange process was tried for the processing of the material. Preliminary results indicated significant improvement in the reversibility of the insertion/release cycles.
An improved cathodic material has been obtained by doping vanadium oxide hydrogel with silver. Silver-doped vanadium pentoxides with a silver molar fraction ranging from 0.01 to 1 were synthesized. With the successful doping, the electronic conductivity of V2O5 was increased by 2 to 3 orders of magnitude. The electrochemical performance of the silver doped materials is very high, up to 4 moles of lithium per mole of silver-doped V2O5 were found to be reversibly intercalated. In addition, the lithium diffusion coefficient is found to be high in the silver-doped material and with a smaller dependence on the lithium intercalation level. These enhancements resulted in high rates of insertion and delivered capacities.