| 1. |
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| 2. |
- Klionsky, Daniel J., et al.
(författare)
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Guidelines for the use and interpretation of assays for monitoring autophagy
- 2012
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Ingår i: Autophagy. - : Informa UK Limited. - 1554-8635 .- 1554-8627. ; 8:4, s. 445-544
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Forskningsöversikt (refereegranskat)abstract
- In 2008 we published the first set of guidelines for standardizing research in autophagy. Since then, research on this topic has continued to accelerate, and many new scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Accordingly, it is important to update these guidelines for monitoring autophagy in different organisms. Various reviews have described the range of assays that have been used for this purpose. Nevertheless, there continues to be confusion regarding acceptable methods to measure autophagy, especially in multicellular eukaryotes. A key point that needs to be emphasized is that there is a difference between measurements that monitor the numbers or volume of autophagic elements (e.g., autophagosomes or autolysosomes) at any stage of the autophagic process vs. those that measure flux through the autophagy pathway (i.e., the complete process); thus, a block in macroautophagy that results in autophagosome accumulation needs to be differentiated from stimuli that result in increased autophagic activity, defined as increased autophagy induction coupled with increased delivery to, and degradation within, lysosomes (in most higher eukaryotes and some protists such as Dictyostelium) or the vacuole (in plants and fungi). In other words, it is especially important that investigators new to the field understand that the appearance of more autophagosomes does not necessarily equate with more autophagy. In fact, in many cases, autophagosomes accumulate because of a block in trafficking to lysosomes without a concomitant change in autophagosome biogenesis, whereas an increase in autolysosomes may reflect a reduction in degradative activity. Here, we present a set of guidelines for the selection and interpretation of methods for use by investigators who aim to examine macroautophagy and related processes, as well as for reviewers who need to provide realistic and reasonable critiques of papers that are focused on these processes. These guidelines are not meant to be a formulaic set of rules, because the appropriate assays depend in part on the question being asked and the system being used. In addition, we emphasize that no individual assay is guaranteed to be the most appropriate one in every situation, and we strongly recommend the use of multiple assays to monitor autophagy. In these guidelines, we consider these various methods of assessing autophagy and what information can, or cannot, be obtained from them. Finally, by discussing the merits and limits of particular autophagy assays, we hope to encourage technical innovation in the field.
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| 3. |
- Kim, Joon Tae, et al.
(författare)
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Dual antiplatelet Use for extended period taRgeted to AcuTe ischemic stroke with presumed atherosclerotic OrigiN (DURATION) trial : Rationale and design
- 2023
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Ingår i: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 18:8, s. 1015-1020
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Tidskriftsartikel (refereegranskat)abstract
- Rationale: The optimal duration of dual antiplatelet therapy (DAPT) with clopidogrel-aspirin for the large artery atherosclerotic (LAA) stroke subtype has been debated. Aims: To determine whether the 1-year risk of recurrent vascular events could be reduced by a longer duration of DAPT in patients with the LAA stroke subtype. Methods and study design: A total of 4806 participants will be recruited to detect a statistically significant relative risk reduction of 22% with 80% power and a two-sided alpha error of 0.05, including a 10% loss to follow-up. This is a registry-based, multicenter, prospective, randomized, open-label, blinded end point study designed to evaluate the efficacy and safety of a 12-month duration of DAPT compared with a 3-month duration of DAPT in the LAA stroke subtype. Patients will be randomized (1:1) to either DAPT for 12 months or DAPT for 3 months, followed by monotherapy (either aspirin or clopidogrel) for the remaining 9 months. Study outcomes: The primary efficacy outcome of the study is a composite of stroke (ischemic or hemorrhagic), myocardial infarction, and all-cause mortality for 1 year after the index stroke. The secondary efficacy outcomes are (1) stroke, (2) ischemic stroke or transient ischemic attack, (3) hemorrhagic stroke, and (4) all-cause mortality. The primary safety outcome is major bleeding. Discussion: This study will help stroke physicians determine the appropriate duration of dual therapy with clopidogrel-aspirin for patients with the LAA stroke subtype. Trial registration: URL: https://cris.nih.go.kr/cris. CRIS Registration Number: KCT0004407.
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| 4. |
- Cho, Wonkyung, et al.
(författare)
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Design of salmon calcitonin particles for nasal delivery using spray-drying and novel supercritical fluid-assisted spray-drying processes
- 2015
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Ingår i: International Journal of Pharmaceutics. - : Elsevier BV. - 0378-5173 .- 1873-3476. ; 478:1, s. 288-296
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Tidskriftsartikel (refereegranskat)abstract
- The overall aim of this study was to prepare a nasal powder formulation of salmon calcitonin (sCT) using an absorption enhancer to improve its bioavailability. In this work, powder formulations for nasal delivery of sCT were studied using various absorption enhancers and stabilizers. Powders were prepared by two different methods: conventional spray-drying (SD) and novel supercritical fluid-assisted spray-drying (SASD) to investigate the role of CO2 in the particle formation process. The prepared sCT powder formulations were characterized by several analyses; powder X-ray diffractometry (PXRD), scanning electron microscopy (SEM), and the Fourier transform infrared (FT-IR) spectroscopy method. The particle size distribution was also evaluated. In vivo absorption tests were carried out in Sprague-Dawley rat using the prepared powder formulations, and the results were compared to those of raw sCT. Quantitative analysis by high-performance liquid chromatography (HPLC) indicated that sCT was chemically stable after both the SD and SASD processes. Results of PXRD, SEM, and FT-IR did not indicate a strong interaction or defragmentation of sCT. The in vivo absorption test showed that SD- and SASD-processed sCT powders increased the bioavailability of the drug when compared to the nasal administration of raw sCT. In addition, SASD-processed sCT exhibited higher nasal absorption when compared with SD-processed sCT in all formulations due to a reduction of particle size. The results from this study illustrate that the preparation of nasal powders using the SASD process could be a promising approach to improve nasal absorption of sCT.
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| 5. |
- Sung, Sang Hyun, et al.
(författare)
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Flexible wireless powered drug delivery system for targeted administration on cerebral cortex
- 2018
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Ingår i: Nano Energy. - : ELSEVIER SCIENCE BV. - 2211-2855 .- 2211-3282. ; 51, s. 102-112
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Tidskriftsartikel (refereegranskat)abstract
- The controlled drug delivery devices helps timely drug administrations and maintenance of effective dose to maximize curing effects with minimal side effects. Application of this technology to various body parts has been limited, especially in organs with curved surface, such as the brain and the eye. Herein, we report a flexible drug delivery microdevice (f-DDM) for controlled administration on the curved organ surface. The unique structure of the f-DDM consists of freestanding gold membranes over the multireservoir array was implemented by reversing the typical fabrication order of the reservoir and sealing membrane. We optimized the design of the f-DDM by a finite element analysis to prevent thermal damage during the laser transfer and the applying current density for reliable drug release through an electrochemical analysis. The wireless power transfer system was applied to f-DDM, which shows stable wirelessly powered operation. The f-DDM was flexible enough to be implantable on the curved cerebral cortex and successfully adopted for delivery of two different chemicals or prevention of seizure activity using an anti-epileptic drug. Our study opens a new avenue for the controlled, region-specific, and combinatorial application of drugs, the key factors for precision medicine.
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| 6. |
- Wang, Tiegang, et al.
(författare)
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Study on nanocrystalline Cr2O3 films deposited by arc ion plating: I. composition, morphology, and microstructure analysis
- 2012
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972. ; 206:10, s. 2629-2637
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Tidskriftsartikel (refereegranskat)abstract
- Nanocrystalline Cr2O3 thin films were deposited on silicon wafers with (100) orientation by arc ion plating (AIP) technique at various negative bias voltages. By virtue of X-ray diffraction analysis, scanning electron microscope, and high-resolution transmission electron microscope, the influence of substrate bias voltage on the film growth process, microstructure, and characteristics was investigated systematically, including the phase constituents, grain size, lattice constant, chemical compositions, as well as surface and cross-section morphologies. With increasing the bias voltage, the grain size and lattice constant of AIP Cr2O3 films first decreased slightly, and then increased gradually again. Both reached the minimum (35 nm and 13.57 angstrom) when the bias voltage was - 100 V. However, the bias voltage had little effect on the phase constituents and chemical compositions of AIP Cr2O3 films. During the film growth process, the surfaces of Cr2O3 films were getting smoother with the negative bias voltage increase, in the meantime, their microstructures evolved from coarse columnar grains to fine columnar grains, short columnar recrystallized grains, and fine columnar grains again. (C) 2011 Elsevier B.V. All rights reserved.
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| 7. |
- Lebegue, Sebastien, et al.
(författare)
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Semimetallic dense hydrogen above 260 GPa
- 2012
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 109:25, s. 9766-9769
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Tidskriftsartikel (refereegranskat)abstract
- Being the lightest and the most abundant element in the universe, hydrogen is fascinating to physicists. In particular, the conditions of its metallization associated with a possible superconducting state at high temperature have been a matter of much debate in the scientific community, and progress in this field is strongly correlated with the advancements in theoretical methods and experimental techniques. Recently, the existence of hydrogen in a metallic state was reported experimentally at room temperature under a pressure of 260-270 GPa, but was shortly after that disputed in the light of more experiments, finding either a semimetal or a transition to an other phase. With the aim to reconcile the different interpretations proposed, we propose by combining several computational techniques, such as density functional theory and the GW approximation, that phase III at ambient temperature of hydrogen is the Cmca-12 phase, which becomes a semimetal at 260 GPa. From phonon calculations, we demonstrate it to be dynamically stable; calculated electron-phonon coupling is rather weak and therefore this phase is not expected to be a high-temperature superconductor.
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| 8. |
- Li, Bing, et al.
(författare)
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Rhodium dihydride (RhH(2)) with high volumetric hydrogen density
- 2011
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 108:46, s. 18618-18621
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Tidskriftsartikel (refereegranskat)abstract
- Materials with very high hydrogen density have attracted considerable interest due to a range of motivations, including the search for chemically precompressed metallic hydrogen and hydrogen storage applications. Using high-pressure synchrotron X-ray diffraction technique and theoretical calculations, we have discovered a new rhodium dihydride (RhH(2)) with high volumetric hydrogen density (163.7 g/L). Compressing rhodium in fluid hydrogen at ambient temperature, the fcc rhodium metal absorbs hydrogen and expands unit-cell volume by two discrete steps to form NaCl-typed fcc rhodium monohydride at 4 GPa and fluorite-typed fcc RhH(2) at 8 GPa. RhH(2) is the first dihydride discovered in the platinum group metals under high pressure. Our low-temperature experiments show that RhH(2) is recoverable after releasing pressure cryogenically to 1 bar and is capable of retaining hydrogen up to 150 K for minutes and 77 K for an indefinite length of time.
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| 9. |
- Mao, Wendy L., et al.
(författare)
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Distortions and stabilization of simple-cubic calcium at high pressure and low temperature
- 2010
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Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 107:22, s. 9965-9968
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Tidskriftsartikel (refereegranskat)abstract
- Ca-III, the first superconducting calcium phase under pressure, was identified as simple-cubic (sc) by previous X-ray diffraction (XRD) experiments. In contrast, all previous theoretical calculations showed that sc had a higher enthalpy than many proposed structures and had an imaginary (unstable) phonon branch. By using our newly developed submicrometer high-pressure single-crystal XRD, cryogenic high-pressure XRD, and theoretical calculations, we demonstrate that Ca-III is neither exactly sc nor any of the lower-enthalpy phases, but sustains the sc-like, primitive unit by a rhombohedral distortion at 300 K and a monoclinic distortion below 30 K. This surprising discovery reveals a scenario that the high-pressure structure of calcium does not go to the zero-temperature global enthalpy minimum but is dictated by high-temperature anharmonicity and low-temperature metastability fine-tuned with phonon stability at the local minimum.
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| 10. |
- Wang, Tie Gang, et al.
(författare)
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In-situ heat treatment study on the nanocrystalline Cr 2 O 3 film using an environmental scanning electron microscope
- 2017
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Ingår i: Coatings. - : MDPI AG. - 2079-6412. ; 7:12
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the surface morphology changes of nanocrystalline Cr 2 O 3 film deposited on Si wafer during the heating process were observed in-situ by means of an environmental scanning electron microscope (ESEM). The Cr 2 O 3 film cracked at high temperature due to the cause of thermal stress; the corresponding crack area percentages on the film surface were real-time evaluated using image analysis software (SISC IAS V8.0) based on the principle of gray value analysis. In the meantime, the effects of the heating temperature on the crack area percentage, phase constituents, and grain size of the Cr 2 O 3 film were also studied in detail. The results showed that the percentage of crack area on film surface first increased with the heating temperature rise, and reached the maximum value at around 980 °C, and then gradually declined again. The above trend is closely related to the changes of thermal stress and grain growth in film. In addition, the heat treatment also had a strong influence on the grain size of the Cr 2 O 3 film.
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| 11. |
- Wang, Tiegang, et al.
(författare)
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High-temperature thermal stability of nanocrystalline Cr2O3 films deposited on silicon wafers by arc ion plating
- 2013
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972. ; 228, s. 140-147
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the high-temperature thermal stability of nanocrystalline Cr2O3 films on Si wafers deposited at various bias voltages was systematically investigated by means of a symmetrical high-resolution thermogravimetric system. In the meantime, the effects of substrate bias voltage on the morphology, microstructure, crack area percentage, phase constituents, and grain size of the heat-treated Cr2O3 films were also studied in detail. The results showed that the Cr2O3 films presented the higher thermal stability in pure nitrogen than in air up to 1200 degrees C because the brittle oxidation product was more prone to cracking and chipping. As the bias voltage was -100 V, the Cr2O3 film showed the highest thermal stability which was attributed to its most compact structure and the lowest defect density. After the heat treatments, all the films cracked due to the big difference in thermal expansion coefficient between the Cr2O3 film and Si wafer, which caused large thermal stresses. And some obvious micro-cavities were left in the film cross section after oxidation owing to the vaporization of Cr2O3 in oxygen containing atmosphere. In addition, the heat treatment also had a strong influence on the grain size of the Cr2O3 films. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.
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| 12. |
- Wang, Tiegang, et al.
(författare)
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Influence of residual stress on the adhesive behavior of detonation gun sprayed WC-Co coatings
- 2012
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Ingår i: Current Applied Physics. - : Elsevier BV. - 1567-1739. ; 12, s. 59-62
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Tidskriftsartikel (refereegranskat)abstract
- The residual stresses generated during D-Gun spraying process act as pre-existing stresses and seriously affect the various types of coating performance. To produce a reliable coating, it is necessary to know the influence of residual stress on the adhesive behavior of coating/substrate system. Based on the residual stress formula for thick coatings and accurate curvature measurements, the residual stresses of D-Gun sprayed WC-Co coatings were obtained. And a strong link was built between the residual stress and the adhesive strength of the coating, namely, the compressive stress in the coating could significantly improve the adhesion, whereas the tensile stress weakened the adhesion. The larger compressive residual stress is in the coating, the stronger adhesion between the coating and substrate. (C) 2012 Elsevier B.V. All rights reserved.
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| 13. |
- Wang, Tiegang, et al.
(författare)
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Study on nanocrystalline Cr2O3 films deposited by arc ion plating: II. Mechanical and tribological properties
- 2012
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Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972. ; 206:10, s. 2638-2644
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Tidskriftsartikel (refereegranskat)abstract
- In this work, the influence of substrate bias voltage on the microhardness, adhesive strength, friction coefficient, and wear rate of AIP Cr2O3 films deposited on AISI 304 stainless steel substrates was investigated systematically. In the meantime, the wear failure mechanism of AIP Cr2O3 films in dry sliding contact was also analyzed and discussed. The results showed that the mechanical properties, adhesive behaviors, and tribological performance of AIP Cr2O3 films were greatly altered by applying a negative bias voltage. With increasing the bias voltage, the hardness, critical load, and tribological performance of AIP Cr2O3 films first were improved gradually, and then were impaired slightly again. When the bias voltage is - 100 V. the Cr2O3 film possessed the highest hardness, the strongest adhesion, and the best wear resistance. The essence of above phenomena was attributed to the variations of microstructure and defect density in the films induced by the substrate bias voltage increase. The main wear failure mechanism of AIP Cr2O3 films is crack initiation and propagation under the high contact stresses, inducing the local film with small area to flake off gradually, and eventually leading to the formation of a wear scar. Crown Copyright (C) 2011 Published by Elsevier B.V. All rights reserved.
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| 14. |
- Wu, Zhengtao, et al.
(författare)
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In situ nanoindentation measurements of arc-evaporated Cr0.49Al0.51N, Al0.66Ti0.34N, and Al0.65Ti0.33Y0.02N films up to 800 degrees C
- 2020
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Ingår i: Journal of Vacuum Science and Technology B. - : A V S AMER INST PHYSICS. - 2166-2746 .- 2166-2754. ; 38:2
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Tidskriftsartikel (refereegranskat)abstract
- In this study, the in situ hardness and elastic modulus measurements of arc-evaporated Cr0.49Al0.51N, Al0.66Ti0.34N, and Al0.65Ti0.33Y0.02N films are investigated using a high-temperature nanoindentation tester. It is found that the hardness of Cr0.49Al0.51N initially increases from 30.2 +/- 2.3GPa at room temperature (RT) and reaches a maximum of 33.2 +/- 2.4GPa at 600 degrees C before decreasing to 27.9 +/- 2.1GPa at 800 degrees C. However, the results for elastic modulus versus temperature follow a degraded trend, with 405 +/- 23GPa for RT, decreasing to 280 +/- 18GPa at 800 degrees C. Increases in the hardness and the elastic modulus can be achieved for both Al0.66Ti0.34N and Al0.65Ti0.33Y0.02N films as their temperatures increase. The addition of Y effectively promotes the hardness and the elastic modulus of Al0.66Ti0.34N at RT-300 degrees C. However, both hardness and elastic modulus change slightly as Y is incorporated at 300-800 degrees C.
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| 15. |
- Zhang, Quan, et al.
(författare)
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Improving the mechanical and anti-wear properties of AlTiN coatings by the hybrid arc and sputtering deposition
- 2019
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Ingår i: Surface & Coatings Technology. - : ELSEVIER SCIENCE SA. - 0257-8972 .- 1879-3347. ; 378
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Tidskriftsartikel (refereegranskat)abstract
- Arc-evaporated AITiN coatings with remarkable adhesion and thermal stability are widely used in manufacturing. However, the large residual stress and surface roughness limit their high-level applications for advanced machining. In this study, a hybrid technique combining cathodic arc evaporation and magnetron sputtering was utilized to enhance the mechanical properties and wear resistance of AlxTi1-xN with x = similar to 0.65. The hybrid AIM coatings exhibited a nano-multilayer architecture with alternating arc-evaporated and magnetron sputtered constituents, which decreased their residual stress from -7.1 GPa to about -5.0 GPa. In addition, the hybrid AlTiN showed higher indentation toughness than the monolithic coatings. The hybrid AITiN coating with a target sputtering power of 7.0 kW showed excellent wear resistance at room and high temperature. At 800 degrees C, the hybrid coatings mainly showed abrasive and oxidation wear, while the monolithic AITiN coating showed abrasive/oxidation wear and brittle failure.
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