Separating structure and electrons in VO2Above 341 kelvin—not far from room temperature—bulk vanadium dioxide (VO2) is a metal. But as soon as the material is cooled below 341 kelvin, VO2 turns into ...an insulator and, at the same time, changes its crystal structure from rutile to monoclinic. Lee et al. studied the peculiar behavior of a heterostructure consisting of a layer of VO2 placed underneath a layer of the same material that has a bit less oxygen. In the VO2 layer, the structural transition occurred at a higher temperature than the metal-insulator transition. In between those two temperatures, VO2 was a metal with a monoclinic structure—a combination that does not occur in the absence of the adjoining oxygen-poor layer.Science, this issue p. 1037The metal-insulator transition in correlated materials is usually coupled to a symmetry-lowering structural phase transition. This coupling not only complicates the understanding of the basic mechanism of this phenomenon but also limits the speed and endurance of prospective electronic devices. We demonstrate an isostructural, purely electronically driven metal-insulator transition in epitaxial heterostructures of an archetypal correlated material, vanadium dioxide. A combination of thin-film synthesis, structural and electrical characterizations, and theoretical modeling reveals that an interface interaction suppresses the electronic correlations without changing the crystal structure in this otherwise correlated insulator. This interaction stabilizes a nonequilibrium metallic phase and leads to an isostructural metal-insulator transition. This discovery will provide insights into phase transitions of correlated materials and may aid the design of device functionalities.
The neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) are prognostic factors for various types of cancer. In this study, we assessed the association of NLR and PLR with the ...prognosis of small-cell lung cancer (SCLC) in patients who received the standard treatment.
We retrospectively reviewed patients who were diagnosed with SCLC and treated with platinum-based chemotherapy between July 2006 and October 2013 in Gyeongsang National University Hospital Regional Cancer Center and Changwon Samsung Hospital.
In total, 187 patients were evaluated. Compared with low NLR (<4), high NLR (⩾4) at diagnosis was associated with poor performance status, advanced stage, and lower response rate. Median overall survival (OS) and progression-free survival (PFS) were worse in the high-NLR group (high vs low, 11.17 vs 9.20 months, P=0.019 and 6.90 vs 5.49 months, P=0.005, respectively). In contrast, PLR at diagnosis was not associated with OS or PFS (P=0.467 and P=0.205, respectively). In multivariate analysis, stage, lactate dehydrogenase, and NLR at diagnosis were independent prognostic factors for OS and PFS.
NLR is easily measurable and reflects the SCLC prognosis. A future prospective study is warranted to confirm our results.
A microstructure-based integrated crystal plasticity (CP) and continuum damage mechanics (CDM) model is proposed for simulating rolling contact fatigue (RCF). The damage process through the formation ...of the dark etching region (DER) under RCF is implemented, i.e., a DER-CPCDM approach. A hierarchical microstructure of lath martensite is virtually generated by the Voronoi tessellation technique and the theoretical Kurdjumov-Sachs orientation relationship between the prior austenite grains and substructures of lath martensite. Moreover, the micro-plasticity calculated from the polycrystal finite element is coupled with dislocation-assisted carbon migration theory, which enables accurate predictions of the deformation inhomogeneity and the DER/damage distribution at the subsurface. The RCF lifespan of AISI 52100 bearing steel can be predicted within reasonable accuracy, in terms of Weibull probability analysis, when the jump-in-cycles approach is implemented in the DER-CPCDM model. The predicted representative lifespan of the Weibull plot is within an error of 13% when compared with reported experimental data. Process factors, including contact pressure, rotational speed, temperature, carbon concentration, and grain size, are analyzed in a numerical sensitivity study, which can be utilized for potential optimization of the RCF process for improving the performance of materials and parts.
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•An integrated model coupling microstructure-based crystal plasticity and continuum damage mechanics is developed.•Microstructure evolution through dislocation assisted carbon migration, or dark etching region, can be modeled.•Hierarchical martensitic microstructure can be implemented through RVE and Kurdjumov-Sachs relation.•The integrated computational model accurately predicts the lifespan of rolling contact fatigue of steel.
In a growing number of galaxy clusters diffuse extended radio sources have been found. These sources are not directly associated with individual cluster galaxies. The radio emission reveal the ...presence of cosmic rays and magnetic fields in the intracluster medium (ICM). We classify diffuse cluster radio sources into radio halos, cluster radio shocks (relics), and revived AGN fossil plasma sources. Radio halo sources can be further divided into giant halos, mini-halos, and possible “intermediate” sources. Halos are generally positioned at cluster center and their brightness approximately follows the distribution of the thermal ICM. Cluster radio shocks (relics) are polarized sources mostly found in the cluster’s periphery. They trace merger induced shock waves. Revived fossil plasma sources are characterized by their radio steep-spectra and often irregular morphologies. In this review we give an overview of the properties of diffuse cluster radio sources, with an emphasis on recent observational results. We discuss the resulting implications for the underlying physical acceleration processes that operate in the ICM, the role of relativistic fossil plasma, and the properties of ICM shocks and magnetic fields. We also compile an updated list of diffuse cluster radio sources which will be available on-line (
http://galaxyclusters.com
). We end this review with a discussion on the detection of diffuse radio emission from the cosmic web.
Mass extinctions occur frequently in natural history. While studies of animals that became extinct can be informative, it is the survivors that provide clues for mechanisms of adaptation when ...conditions are adverse. Here, we describe a survival pathway used by many species as a means for providing adequate fuel and water, while also providing protection from a decrease in oxygen availability. Fructose, whether supplied in the diet (primarily fruits and honey), or endogenously (via activation of the polyol pathway), preferentially shifts the organism towards the storing of fuel (fat, glycogen) that can be used to provide energy and water at a later date. Fructose causes sodium retention and raises blood pressure and likely helped survival in the setting of dehydration or salt deprivation. By shifting energy production from the mitochondria to glycolysis, fructose reduced oxygen demands to aid survival in situations where oxygen availability is low. The actions of fructose are driven in part by vasopressin and the generation of uric acid. Twice in history, mutations occurred during periods of mass extinction that enhanced the activity of fructose to generate fat, with the first being a mutation in vitamin C metabolism during the Cretaceous–Paleogene extinction (65 million years ago) and the second being a mutation in uricase that occurred during the Middle Miocene disruption (12–14 million years ago). Today, the excessive intake of fructose due to the availability of refined sugar and high‐fructose corn syrup is driving ‘burden of life style’ diseases, including obesity, diabetes and high blood pressure.
Content List ‐ This is an article from the symposium: “Bioinspirational medicine”.
Summary
Background
Coeliac disease (CD), originally thought to be largely confined to Northern Europe and Australasia and uncommon in North America and the Middle East, is now recognised to be ...equally common in all these countries. It is still thought to be rare in the Orient and Sub‐Saharan Africa.
Aim
To assess geographical differences and time trends in the frequency of CD.
Methods
Medline and Embase searches were conducted on 10 November 2012, from 1946 and 1980 respectively, using the key words: coeliac disease or celiac disease + prevalence or incidence or frequency.
Results
There were significant intra‐ and inter‐country differences in the prevalence and incidence of CD. Only 24 ethnic Chinese and Japanese patients have been reported in the English literature. Of CD‐associated HLA DQ antigens, DQ2 occurs in 5–10% of Chinese and sub‐Saharan Africans, compared to 5–20% in Western Europe. DQ8 occurs in 5–10% of English, Tunisians and Iranians, but in <5% of Eastern Europeans, Americans and Asians. The prevalence and incidence of both clinically and serologically diagnosed CD increased in recent years. These geographical and temporal differences seem genuine, although variable indices of suspicion and availability of diagnostic facilities are confounding factors.
Conclusions
Coeliac disease is increasing in frequency, with significant geographical differences. Although few cases have been described to date in the Orient and Sub‐Saharan Africa, there is a significant prevalence of HLA DQ2 and wheat consumption is of the same order as that in Western Europe. CD may therefore become more common in the future in these countries.
Background
Few studies have investigated the incidence of anaphylaxis induced by individual or structurally similar cephalosporins. The aims of the study were to assess the incidence of ...cephalosporin‐induced anaphylaxis and evaluate the clinical efficacy of screening skin tests.
Methods
In this retrospective cohort study, we obtained information on total cephalosporin use and cephalosporin‐induced anaphylaxis in intravenous cephalosporin recipients in 12 general hospitals between 2013 and 2015. Cephalosporins were divided into 4 groups according to similar side‐chain structures. The incidence of cephalosporin‐induced anaphylaxis was assessed for each cephalosporin, cephalosporin generation, and side‐chain group. To verify the efficacy of screening intradermal tests (IDT) with cephalosporin, the 12 hospitals were assigned to the intervention or control group depending on whether they performed screening IDT before the administration of cephalosporins.
Results
We identified 76 cases of cephalosporin‐induced anaphylaxis with 1 123 345 exposures to intravenous cephalosporins (6.8 per 100 000 exposures), and the incidence of fatal anaphylaxis by cephalosporin was 0.1 cases per 100 000 exposures. The highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures) and side‐chain group 1 (cefepime, cefotaxime, ceftizoxime, ceftriaxone, and cefuroxime; 9.3 per 100 000). There was no case of anaphylaxis induced by cefoxitin, cefmetazole, cefminox, and cefotiam. The clinical effectiveness of routine screening IDT was not significant (P = .06).
Conclusions
The incidence of cephalosporin‐induced anaphylaxis differed according to individual drugs and side‐chain structure. Screening IDT showed no clinical efficacy at a population level.
Among total 1 140 354 cephalosporin treatment courses from 12 hours hospitals, the incidence of cephalosporin induced anaphylaxis was 6.8 per 100 000 exposures and the related fatality was 1.3%. The incidence of cephalosporin induced anaphylaxis varies with each drug type, and the highest incidences of anaphylaxis occurred in the ceftizoxime (13.0 cases per 100 000 exposures). Screening intradermal tests with cephalosporin failed to show preventive effect on cephalosporin‐induced anaphylaxis.
Hydrographic data collected from research cruises, bottom‐anchored moorings, drifting Ice‐Tethered Profilers, and satellite altimetry in the Beaufort Gyre region of the Arctic Ocean document an ...increase of more than 6,400 km3 of liquid freshwater content from 2003 to 2018: a 40% growth relative to the climatology of the 1970s. This fresh water accumulation is shown to result from persistent anticyclonic atmospheric wind forcing (1997–2018) accompanied by sea ice melt, a wind‐forced redirection of Mackenzie River discharge from predominantly eastward to westward flow, and a contribution of low salinity waters of Pacific Ocean origin via Bering Strait. Despite significant uncertainties in the different observations, this study has demonstrated the synergistic value of having multiple diverse datasets to obtain a more comprehensive understanding of Beaufort Gyre freshwater content variability. For example, Beaufort Gyre Observational System (BGOS) surveys clearly show the interannual increase in freshwater content, but without satellite or Ice‐Tethered Profiler measurements, it is not possible to resolve the seasonal cycle of freshwater content, which in fact is larger than the year‐to‐year variability, or the more subtle interannual variations.
Plain Language
The Beaufort Gyre centered in the Canada Basin of the Arctic Ocean is the major reservoir of fresh water in the Arctic. The primary focus of this study is on quantifying variability and trends in liquid (water) and solid (sea ice) freshwater content in this region. The Beaufort Gyre Exploration Program was initiated in 2003 to synthesize results of historical data analysis, design and conduct long‐term observations, and to provide information for numerical modeling under the umbrella of the FAMOS (Forum for Arctic Observing and Modeling Synthesis) project. The data collected from research cruises, moorings, Ice‐Tethered Profiler observations, and satellite altimetry document an increase of more than 6,400 km3 of liquid freshwater content from 2003 to 2018, a 40% growth relative to the climatology of the 1970s. This fresh water volume is comparable to the fresh water volume released to the sub‐arctic seas during the Great Salinity Anomaly episode of the 1970s. Thus, since the 2000s, the stage has been set for another possible release of fresh water to lower latitudes with accompanying climate impacts, including changes to sea ice conditions, ocean circulation, and ecosystems of the Sub‐Arctic similar to the influence of the Great Salinity Anomaly observed in the 1970s.
Key Points
Beaufort Gyre freshwater content time series (2003–2018) from different data sets are updated, compared, and analyzed
Qualitative and quantitative estimates of factors and mechanisms driving freshwater content changes are provided
In 2003–2018, the major sources of accumulated fresh water were sea ice melt, Mackenzie River runoff, and Bering Strait transport
ObjectivesSerous cystic neoplasm (SCN) is a cystic neoplasm of the pancreas whose natural history is poorly known. The purpose of the study was to attempt to describe the natural history of SCN, ...including the specific mortality.DesignRetrospective multinational study including SCN diagnosed between 1990 and 2014.Results2622 patients were included. Seventy-four per cent were women, and median age at diagnosis was 58 years (16–99). Patients presented with non-specific abdominal pain (27%), pancreaticobiliary symptoms (9%), diabetes mellitus (5%), other symptoms (4%) and/or were asymptomatic (61%). Fifty-two per cent of patients were operated on during the first year after diagnosis (median size: 40 mm (2–200)), 9% had resection beyond 1 year of follow-up (3 years (1–20), size at diagnosis: 25 mm (4–140)) and 39% had no surgery (3.6 years (1–23), 25.5 mm (1–200)). Surgical indications were (not exclusive) uncertain diagnosis (60%), symptoms (23%), size increase (12%), large size (6%) and adjacent organ compression (5%). In patients followed beyond 1 year (n=1271), size increased in 37% (growth rate: 4 mm/year), was stable in 57% and decreased in 6%. Three serous cystadenocarcinomas were recorded. Postoperative mortality was 0.6% (n=10), and SCN's related mortality was 0.1% (n=1).ConclusionsAfter a 3-year follow-up, clinical relevant symptoms occurred in a very small proportion of patients and size slowly increased in less than half. Surgical treatment should be proposed only for diagnosis remaining uncertain after complete workup, significant and related symptoms or exceptionally when exists concern with malignancy. This study supports an initial conservative management in the majority of patients with SCN.Trial registration numberIRB 00006477.
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