534 research outputs found
A new family of bridge functions for electrolyte solutions
We present a new set of closures for restricted models of electrolyte solutions
at the McMillan-Mayer level that improve upon the Hypernetted Chain
prediction for the ion-ion pair correlation functions. The improvement is accomplished
by proposing simple functional forms for the bridge functions
and the specification of certain adjusting parameters according to several
criteria. Under the new closures, and unlike the HNC case, the “sum” direct
correlation function, which is crucial for determining the stability of the
solution with respect to phase separation, remains finite at thermodynamic
states along the spinodal and at the critical point.Для спрощених моделей розчинів електролітів ми представляємо
новий набір замикань на рівні МакМіллана–Маєра, який покращує
передбачення для парних кореляційних функцій іон-іон, отриманих
у гіперланцюговому наближенні. Покращення здійснюється введенням простих функціональних форм для місткових функцій і деяких
підгоночних параметрів, які відповідають різним критеріям. При нових умовах замикання, на противагу до гіперланцюгового наближення, пряма кореляційна функція “сума”, що є важливою для визначення стійкості розв’язку по відношенню до фазового розділення, залишається скінченою при термодинамічних станах уздовж спінодалі і в
критичній точці
Should we continue to use prediction tools to identify patients at risk of Candida spp. infection? If yes, why?
We read with interest the article from Shanin et al. about the Fungal Infection Risk Evaluation (FIRE) study [1] aiming to 'describe the incidence of IFD in UK critical care units and to develop and validate a clinical risk prediction tool to identify non-neutropenic, critically ill adult patients at risk of IFD'. The investigators should be congratulated for the way they collected a huge amount of data from 96 adult intensive care units (ICUs), managed the FIRE database, and developed and validated the risk model. However, they stated that the prediction model would help to identify patients who may benefit from antifungal prophylaxis and that a number of randomized controlled trials (RCTs) demonstrated a beneficial effect of antifungal prophylaxis and/or empiric treatment in terms of incidence of invasive fungal disease (IFD) and mortality. This statement is not supported by available evidence from RCTs. A recent Cochrane Systematic Review including 22 RCTs evaluating prophylaxis, pre-emptive, and empiric antifungal treatment with any antifungal drugs in 2761 non-neutropenic critically ill patients showed no significant effect on mortality (risk ratio (RR) 0.93, 95 % confidence interval (CI) 0.79 to 1.09) and a significant reduction in the risk of invasive fungal infection (IFI) (RR 0.57, 95 % CI 0.39 to 0.83) [2, 3]. In the subgroup analysis for type of intervention, antifungal prophylaxis was not associated with a significant mortality reduction but with a significant reduction of IFI [4]. This systematic review was the update of the one cited in the manuscript and published in 2006 including 12 RCT and 1606 patients
CaCu3Ti4O12 single crystals: insights on growth and nanoscopic investigation
The combination of scanning impedance microscopy and conductive atomic force microscopy was
applied to single crystals of the perovskite-type oxide CaCu3Ti4O12 (CCTO) in order to provide a local
dielectric characterization on ingot sections. Both techniques clearly showed dielectric heterogeneities
due to the presence of inclusions within crystals grown in different laboratories. Despite macroscopic
characterizations, such as Laue diffraction, gave no indications for the presence of inclusions within the
crystals, the discovery of dielectric heterogeneities prompted a careful structural analysis, which
revealed the presence of crystalline CaTiO3 (CTO) precipitates. Thus, the scanning probe investigation
provided the evidence for the electrical homogeneity within the CCTO crystal and the presence of
internal barriers due to the CCTO/CTO interfaces
Opioid use and effectiveness of its prescription at discharge in an acute pain relief and palliative care unit
The aim of this study was to present how opioids
are used in an acute pain relief and palliative care unit
(APRPCU), where many patients with difficult pain conditions
are admitted from GPs, home palliative care programs,
oncology departments, other hospitals or emergency units,
and other regional places. From a consecutive sample of
cancer patients admitted to an APRPCU for a period of
6 months, patients who had been administered opioids were
included in this survey. Basic information was collected as
well as opioid therapy prescribed at admission and, subsequently,
during admission and at time of discharge. Patients
were discharged once stabilization of pain and symptoms
were obtained and the treatment was considered to be optimized.
One week after being discharged, patients or relatives
were contacted by phone to gather information about
the availability of opioids at dosages prescribed at time of
discharge. One hundred eighty six of 231 patients were
specifically admitted for uncontrolled pain, with a mean
pain intensity of 6.8 (SD 2.5). The mean dose of oral
morphine equivalents in patients receiving opioids before
admission was 45 mg/day (range 10–500 mg). One hundred
seventy five patients (75.7 %) were prescribed around the
clock opioids at admission. About one third of patients
changed treatment (opioid or route). Forty two of 175
(24 %), 27/58 (46.5 %), 10/22 (45.4 %), and 2/4 (50 %)
patients were receiving more than 200 mg of oral morphine
equivalents, as maximum dose of the first, second, third, and
fourth opioid prescriptions, respectively. The pattern of
opioids changed, with the highest doses administered with
subsequent line options. The mean final dose of opioids,
expressed as oral morphine equivalents, for all patients was
318 mg/day (SD 798), that is more than six times the doses
of pre-admission opioid doses. One hundred eighty six
patients (80.5 %) were prescribed a breakthrough cancer
pain (BTcP) medication at admission. Sixty five patients
changed their BTcP prescription, and further 27 patients
changed again. Finally, eight patients were prescribed a
fourth BTcP medication. Of 46 patients available for interview,
the majority of them (n=39, 84 %) did not have
problems with their GPs, who facilitated prescription and
availability of opioids at the dosages prescribed at discharge.
For patients with severe distress, APRPCUs may
guarantee a high-level support to optimize pain and symptom
intensities providing intensive approach and resolving
highly distressing situations in a short time by optimizing
the use of opioids
Field Localization and Enhancement of Phase Locked Second and Third Harmonic Generation in Absorbing Semiconductor Cavities
We predict and experimentally observe the enhancement by three orders of
magnitude of phase mismatched second and third harmonic generation in a GaAs
cavity at 650nm and 433nm, respectively, well above the absorption edge. Phase
locking between the pump and the harmonics changes the effective dispersion of
the medium and inhibits absorption. Despite hostile conditions the harmonics
become localized inside the cavity leading to relatively large conversion
efficiencies. Field localization plays a pivotal role and ushers in a new class
of semiconductor-based devices in the visible and UV ranges
An Atypical Case of Taravana Syndrome in a Breath-Hold Underwater Fishing Champion: A Case Report
Dysbaric accidents are usually referred to compressed air-supplied diving. Nonetheless, some cases of decompression illness are known to have occurred among breath-hold (BH) divers also, and they are reported in the medical literature. A male BH diver ((à years old), underwater *shing champion, presented neurological disorders as dizziness, sensory numbness, blurred vision, and le+ frontoparietal pain a+er many dives to a ( meters sea water depth with short surface intervals. Symptoms spontaneously regressed and the patient came back home. )e following morning, pain and neurological impairment occurred again and the diver went by himself to the hospital where he had a generalized tonic-clonic seizure and lost consciousness. A magnetic resonance imaging of the brain disclofsed a cortical T -weighted hypointense area in the temporal region corresponding to infarction with partial hemorrhage. An early hyperbaric oxygen therapy led to prompt resolution of neurological *ndings. All clinical and imaging characteristics were referable to the Taravana diving syndrome, induced by repetitive prolonged deep BH dives. )e reappearance of neurological signs a+er an uncommon ! -hour symptom-free interval may suggest an atypical case of Taravana syndrome
Palaeoclimatic and palaeoenvironmental evolution of the Lower Pleistocene Arda River succession
The Arda River marine succession, cropping out in western Emilia (northern Italy) represents an excellent site to study past ecosystems dynamics in the frame of Early Pleistocene climate change and tectonic activity. This one-day excursion leads the participants to discover the palaeoclimatic and palaeoenvironmental evolution of the Lower Pleistocene Arda River marine section, unraveled through an integrated use of sedimentological, palaeoecological (molluscs and trace fossils) and geochemical tools. Upsection, the succession was deposited in progressively shallower water and colder climate during phases of advance of fan deltas affected by hyperpycnal flows. It culminates at the top with clast supported alluvial conglomerates and freshwater/terrestrial biota indicating a sea level drop and the establishment of a continental environment. It is very rich in fossils: in the marine part molluscs, brachiopods, corals and echinoderms, besides well preserved trace fossils, are abundant; whereas in the continental part a mammal fauna and freshwater/terrestrial molluscs are occasionally found. Sclerochemical analyses undertaken on bivalve shells indicate that seawater temperature seasonality was the main variable of climate change within the study area during the Early Pleistocene. In particular, strong seasonality and low winter palaeotemperatures were assumed to be the main drivers for the widespread establishment of Arctica islandica populations in the palaeo-Adriatic Sea around 1.80 Ma. During the excursion not only fossils are shown, but also interesting biocalcarenitic bodies with a complex geometry cropping out in the town of Castell\u2019Arquato. The excursion is complemented by the visit to the Giuseppe Cortesi geological and palaeontological museum, housing vertebrate and invertebrate fossil collections
Electrical Properties of Self-Assembled Nano-Schottky Diodes
A bottom-up methodology to fabricate a nanostructured material by Au nanoclusters on 6H-SiC surface is illustrated. Furthermore, a methodology to control its structural properties by thermal-induced self-organization of the Au nanoclusters is demonstrated. To this aim, the self-organization kinetic mechanisms of Au nanoclusters on SiC surface were experimentally studied by scanning electron microscopy, atomic force microscopy, Rutherford backscattering spectrometry and theoretically modelled by a ripening process. The fabricated nanostructured materials were used to probe, by local conductive atomic force microscopy analyses, the electrical properties of nano-Schottky contact Au nanocluster/SiC. Strong efforts were dedicated to correlate the structural and electrical characteristics: the main observation was the Schottky barrier height dependence of the nano-Schottky contact on the cluster size. Such behavior was interpreted considering the physics of few electron quantum dots merged with the concepts of ballistic transport and thermoionic emission finding a satisfying agreement between the theoretical prediction and the experimental data. The fabricated Au nanocluster/SiC nanocontact is suggested as a prototype of nano-Schottky diode integrable in complex nanoelectronic circuits
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