Transport, magnetic, and structural properties of La0.7_{0.7}Ce0.3_{0.3}MnO3_3 thin films. Evidence for hole-doping

Cerium-doped manganite thin films were grown epitaxially by pulsed laser deposition at $720 ^\circ$C and oxygen pressure $p_{O_2}=1-25$Pa and were subjected to different annealing steps. According to x-ray diffraction (XRD) data, the formation of CeO$_2$ as a secondary phase could be avoided for $p_{O_2}\ge 8$Pa. However, transmission electron microscopy shows the presence of CeO$_2$ nanoclusters, even in those films which appear to be single phase in XRD. With O$_2$ annealing, the metal-to-insulator transition temperature increases, while the saturation magnetization decreases and stays well below the theoretical value for electron-doped La$_{0.7}$Ce$_{0.3}$MnO$_3$ with mixed Mn$^{3+}$/Mn$^{2+}$ valences. The same trend is observed with decreasing film thickness from 100 to 20 nm, indicating a higher oxygen content for thinner films. Hall measurements on a film which shows a metal-to-insulator transition clearly reveal holes as dominating charge carriers. Combining data from x-ray photoemission spectroscopy, for determination of the oxygen content, and x-ray absorption spectroscopy (XAS), for determination of the hole concentration and cation valences, we find that with increasing oxygen content the hole concentration increases and Mn valences are shifted from 2+ to 4+. The dominating Mn valences in the films are Mn$^{3+}$ and Mn$^{4+}$, and only a small amount of Mn$^{2+}$ ions can be observed by XAS. Mn$^{2+}$ and Ce$^{4+}$ XAS signals obtained in surface-sensitive total electron yield mode are strongly reduced in the bulk-sensitive fluorescence mode, which indicates hole-doping in the bulk for those films which do show a metal-to-insulator transition.Comment: 8 pages, 10 figure

Climate Change and Extreme Events: What Role for Insurance?

Experts expect climate change to affect not just average temperature, but also weather variability and extreme weather events. The effects, including economic and human losses, impose a disproportionate burden on vulnerable developing countries. How can insurance, including public-private arrangements with international support, play a role in helping vulnerable countries adapt? This Policy Brief offers practical guidance to policymakers shaping the post-Copenhagen adaptation strategy

Isolation of human β-defensin-4 in lung tissue and its increase in lower respiratory tract infection

BACKGROUND: Human β-defensin-4 (hBD-4), a new member of the β-defensin family, was discovered by an analysis of the genomic sequence. The objective of this study was to clarify hBD-4 expression in human lung tissue, along with the inducible expression in response to infectious stimuli, localization, and antimicrobial activities of hBD-4 peptides. We also investigated the participation of hBD-4 in chronic lower respiratory tract infections (LRTI) by measuring the concentrations of hBD-4 peptides in human bronchial epithelial lining fluid (ELF). METHODS: The antimicrobial activity of synthetic hBD-4 peptides against E. coli and P. aeruginosa was measured by radial diffusion and colony count assays. We identified hBD-4 in homogenated human lung tissue by reverse-phase high-performance liquid chromatography coupled with a radioimmunoassay (RIA). Localization of hBD-4 was studied through immunohistochemical analysis (IHC). We investigated the effects of lipopolysaccharide (LPS) on hBD-4 expression and its release from small airway epithelial cells (SAEC). We collected ELF from patients with chronic LRTI using bronchoscopic microsampling to measure hBD-4 concentrations by RIA. RESULTS: hBD-4 exhibited salt-sensitive antimicrobial activity against P. aeruginosa. We detected the presence of hBD-4 peptides in human lung tissue. IHC demonstrated the localization of hBD-4-producing cells in bronchial and bronchiolar epithelium. The levels of hBD-4 peptides released from LPS-treated SAECs were higher than those of untreated control cells. ELF hBD-4 was detectable in 4 of 6 patients with chronic LRTI, while the amounts in controls were all below the detectable level. CONCLUSION: This study suggested that hBD-4 plays a significant role in the innate immunity of the lower respiratory tract

Controlling the formation and stability of ultra-thin nickel silicides : an alloying strategy for preventing agglomeration

The electrical contact of the source and drain regions in state-of-the-art CMOS transistors is nowadays facilitated through NiSi, which is often alloyed with Pt in order to avoid morphological agglomeration of the silicide film. However, the solid-state reaction between as-deposited Ni and the Si substrate exhibits a peculiar change for as-deposited Ni films thinner than a critical thickness of t(c) = 5 nm. Whereas thicker films form polycrystalline NiSi upon annealing above 450 degrees C, thinner films form epitaxial NiSi2 films that exhibit a high resistance toward agglomeration. For industrial applications, it is therefore of utmost importance to assess the critical thickness with high certainty and find novel methodologies to either increase or decrease its value, depending on the aimed silicide formation. This paper investigates Ni films between 0 and 15 nm initial thickness by use of "thickness gradients," which provide semi-continuous information on silicide formation and stability as a function of as-deposited layer thickness. The alloying of these Ni layers with 10% Al, Co, Ge, Pd, or Pt renders a significant change in the phase sequence as a function of thickness and dependent on the alloying element. The addition of these ternary impurities therefore changes the critical thickness t(c). The results are discussed in the framework of classical nucleation theory

Optimized fabrication of high quality La0.67Sr0.33MnO3 thin films considering all essential characteristics

In this article, an overview of the fabrication and properties of high quality La0.67Sr0.33MnO3 (LSMO) thin films is given. A high quality LSMO film combines a smooth surface morphology with a large magnetization and a small residual resistivity, while avoiding precipitates and surface segregation. In literature, typically only a few of these issues are adressed. We therefore present a thorough characterization of our films, which were grown by pulsed laser deposition. The films were characterized with reflection high energy electron diffraction, atomic force microscopy, x-ray diffraction, magnetization and transport measurements, x-ray photoelectron spectroscopy and scanning transmission electron microscopy. The films have a saturation magnetization of 4.0 {\mu}B/Mn, a Curie temperature of 350 K and a residual resistivity of 60 {\mu}{\Omega}cm. These results indicate that high quality films, combining both large magnetization and small residual resistivity, were realized. A comparison between different samples presented in literature shows that focussing on a single property is insufficient for the optimization of the deposition process. For high quality films, all properties have to be adressed. For LSMO devices, the thin film quality is crucial for the device performance. Therefore, this research is important for the application of LSMO in devices.Comment: Accepted for publication in Journal of Physics D - Applied Physic

Long-term effect of α1-antitrypsin augmentation therapy on the decline of FEV1 in deficient patients: an analysis of the AIR database

Lung structure and function; COPD and smokingEstructura y función pulmonar; EPOC y tabaquismoEstructura i funció pulmonar; MPOC i tabaquismeBackground Patients with ZZ (Glu342Lys) α-1-antitrypsin deficiency (ZZ-AATD) who received augmentation therapy with α-1-antitrypsin (AAT) in randomised controlled trials over 2–3 years failed to show a significant reduction of the annual decline of forced expiratory volume in 1 s (FEV1). Methods To compare the trajectory of FEV1 change during 4 or more years in ZZ-AATD patients with emphysema receiving or not receiving intravenous augmentation therapy, a retrospective analysis of FEV1 values entered in the Alpha-1 International Registry (AIR) of ZZ-AATD patients from five different European countries (Germany, UK, Spain, Italy and the Netherlands) was performed. The post-bronchodilator FEV1 % predicted values for baseline and follow-up over time from patients were analysed using linear mixed effects models. Results Data of 374 patients were analysed: 246 untreated and 128 treated with intravenous AAT augmentation therapy. The mean±sd follow-up duration of the untreated group was 8.60±3.34 years and 8.59±2.62 years for the treated group. The mixed effects model analysis showed a mean FEV1 decline of −0.931% predicted per year (95% CI −1.144 to −0.718) in the untreated group and a decline of −1.016% predicted per year (95% CI −1.319 to −0.7145) in the treated group. The likelihood ratio test showed no difference between the two groups (p=0.71). Conclusion In our study population, we could not detect a significant difference in the annual decline of FEV1 by AAT augmentation treatment over a mean period of 8.6 years. Other approaches are needed to validate any benefit of augmentation therapy.This study was supported by Stichting AIR

Extracorporeal membrane oxygenation (ECMO) as salvage treatment for pulmonary Echinococcus granulosus infection with acute cyst rupture

Extracorporeal membrane oxygenation (ECMO) has been used successfully for the treatment of patients with respiratory failure due to severe infections. Although rare, parasites can also cause severe pulmonary disease. Tapeworms of the genus Echinococcus give rise to the development of cystic structures in the liver, lungs, and other organs. Acute cyst rupture leads to potentially life-threatening infection, and affected patients may deteriorate rapidly. The case of a young woman from Bulgaria who was admitted to hospital with severe dyspnoea, progressive chest pain, and haemoptysis is described. Computed tomography of the chest was pathognomonic for cystic echinococcosis with acute cyst rupture. Following deterioration on mechanical ventilation, she was cannulated for veno-venous ECMO. The patient's condition improved considerably, and she was weaned successfully from ECMO and mechanical ventilation. Following lobectomy of the affected left lower lobe, the patient was discharged home in good condition. This appears to be the first report of the successful use of ECMO as salvage treatment for a severe manifestation of a helminthic disease. Due to recent migration to Western Europe, the number of patients presenting with respiratory failure due to pulmonary echinococcosis with cyst rupture is likely to increase

Extracorporeal membrane oxygenation (ECMO) as salvage treatment for pulmonary Echinococcus granulosus infection with acute cyst rupture

Extracorporeal membrane oxygenation (ECMO) has been used successfully for the treatment of patients with respiratory failure due to severe infections. Although rare, parasites can also cause severe pulmonary disease. Tapeworms of the genus Echinococcus give rise to the development of cystic structures in the liver, lungs, and other organs. Acute cyst rupture leads to potentially life-threatening infection, and affected patients may deteriorate rapidly. The case of a young woman from Bulgaria who was admitted to hospital with severe dyspnoea, progressive chest pain, and haemoptysis is described. Computed tomography of the chest was pathognomonic for cystic echinococcosis with acute cyst rupture. Following deterioration on mechanical ventilation, she was cannulated for veno-venous ECMO. The patient’s condition improved considerably, and she was weaned successfully from ECMO and mechanical ventilation. Following lobectomy of the affected left lower lobe, the patient was discharged home in good condition. This appears to be the first report of the successful use of ECMO as salvage treatment for a severe manifestation of a helminthic disease. Due to recent migration to Western Europe, the number of patients presenting with respiratory failure due to pulmonary echinococcosis with cyst rupture is likely to increase

IL-17C-mediated innate inflammation decreases the response to PD-1 blockade in a model of Kras-driven lung cancer

Chronic obstructive pulmonary disease (COPD) is associated with neutrophilic lung infammation and CD8 T cell exhaustion and is an important risk factor for the development of non-small cell lung cancer (NSCLC). The clinical response to programmed cell death-1 (PD-1) blockade in NSCLC patients is variable and likely afected by a coexisting COPD. The pro-infammatory cytokine interleukin-17C (IL-17C) promotes lung infammation and is present in human lung tumors. Here, we used a Krasdriven lung cancer model to examine the function of IL-17C in infammation-promoted tumor growth. Genetic ablation of Il-17c resulted in a decreased recruitment of infammatory cells into the tumor microenvironment, a decreased expression of tumor-promoting cytokines (e.g. interleukin-6 (IL-6)), and a reduced tumor proliferation in the presence of Haemophilus infuenzae- (NTHi) induced COPD-like lung infammation. Chronic COPD-like infammation was associated with the expression of PD-1 in CD8 lymphocytes and the membrane expression of the programmed death ligand (PD-L1) independent of IL-17C. Tumor growth was decreased in Il-17c defcient mice but not in wildtype mice after anti-PD-1 treatment. Our results suggest that strategies targeting innate immune mechanisms, such as blocking of IL-17C, may improve the response to anti-PD-1 treatment in lung cancer patients