| 1. |
- 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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| 2. |
- Dai, Qingyuan, et al.
(författare)
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Severe dioxin-like compound (DLC) contamination in e-waste recycling areas : An under-recognized threat to local health
- 2020
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Ingår i: Environment International. - : Elsevier. - 0160-4120 .- 1873-6750. ; 139
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Tidskriftsartikel (refereegranskat)abstract
- Electrical and electronic waste (e-waste) burning and recycling activities have become one of the main emission sources of dioxin-like compounds (DLCs). Workers involved in e-waste recycling operations and residents living near e-waste recycling sites (EWRS) are exposed to high levels of DLCs. Epidemiological and experimental in vivo studies have reported a range of interconnected responses in multiple systems with DLC exposure. However, due to the compositional complexity of DLCs and difficulties in assessing mixture effects of the complex mixture of e-waste-related contaminants, there are few studies concerning human health outcomes related to DLC exposure at informal EWRS. In this paper, we have reviewed the environmental levels and body burdens of DLCs at EWRS and compared them with the levels reported to be associated with observable adverse effects to assess the health risks of DLC exposure at EWRS. In general, DLC concentrations at EWRS of many countries have been decreasing in recent years due to stricter regulations on e-waste recycling activities, but the contamination status is still severe. Comparison with available data from industrial sites and well-known highly DLC contaminated areas shows that high levels of DLCs derived from crude e-waste recycling processes lead to elevated body burdens. The DLC levels in human blood and breast milk at EWRS are higher than those reported in some epidemiological studies that are related to various health impacts. The estimated total daily intakes of DLCs for people in EWRS far exceed the WHO recommended total daily intake limit. It can be inferred that people living in EWRS with high DLC contamination have higher health risks. Therefore, more well-designed epidemiological studies are urgently needed to focus on the health effects of DLC pollution in EWRS. Continuous monitoring of the temporal trends of DLC levels in EWRS after actions is of highest importance.
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| 3. |
- Ge, Shaofan, et al.
(författare)
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Effects of Al addition on the microstructures and properties of MoNbTaTiV refractory high entropy alloy
- 2020
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Ingår i: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 784
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Tidskriftsartikel (refereegranskat)abstract
- AlxMoNbTaTiV alloys are designed according to the binary phase diagrams and calculation of phase diagrams (CALPHAD). The phase formation and elemental segregation are predicted using the CALPHAD method. The effects of Al on microstructures, and mechnical properties of AlxMoNbTaTiV are investigated, which verified the results of calculated dendritic microstructure and BCC structure. The strengthening mechanism is proved as the result of chemical and electrical interactions. The serration behavior in the compression test at 25 degrees C, 500 degrees C, 700 degrees C, 900 degrees C is discussed. At room temperature, addition of Al enhanced the dynamic aging effects in low concentration. The effects became weaker with the increase of Al content. At 500 degrees C, higher Al concentration leads to stronger serrated flow.
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| 4. |
- Li, Hu, et al.
(författare)
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Photoluminescent Semiconducting Graphene Nanoribbons via Longitudinally Unzipping Single-Walled Carbon Nanotubes
- 2021
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Ingår i: ACS Applied Materials and Interfaces. - : American Chemical Society (ACS). - 1944-8244 .- 1944-8252. ; 13:44, s. 52892-52900
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Tidskriftsartikel (refereegranskat)abstract
- The lack of a sizeable band gap has so far prevented graphene from building effective electronic and optoelectronic devices despite its numerous exceptional properties. Intensive theoretical research reveals that a band gap larger than 1 eV can only be achieved in sub-3 nm wide graphene nanoribbons (GNRs), but real fabrication of such ultranarrow GNRs still remains a critical challenge. Herein, we demonstrate an approach for the synthesis of ultranarrow and photoluminescent semiconducting GNRs by longitudinally unzipping single-walled carbon nanotubes. Atomic force microscopy reveals the unzipping process, and the resulting 2.2 nm wide GNRs are found to emit strong and sharp photoluminescence at similar to 685 nm, demonstrating a very desirable semiconducting nature. This band gap of 1.8 eV is further confirmed by follow-up photoconductivity measurements, where a considerable photocurrent is generated, as the excitation wavelength becomes shorter than 700 nm. More importantly, our fabricated GNR field-effect transistors (FETs), by employing the hexagonal boron nitride-encapsulated heterostructure to achieve edge-bonded contacts, demonstrate a high current on/off ratio beyond 105 and carrier mobility of 840 cm(2)/V s, approaching the theoretical scattering limit in semiconducting GNRs at room temperature. Especially, highly aligned GNR bundles with lengths up to a millimeter are also achieved by prepatterning a template, and the fabricated GNR bundle FETs show a high on/off ratio reaching 10(5), well-defined saturation currents, and strong light-emitting properties. Therefore, GNRs produced by this method open a door for promising applications in graphene-based electronics and optoelectronics.
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| 5. |
- Wang, Rongsheng, et al.
(författare)
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Asymmetry in the current sheet and secondary magnetic flux ropes during guide field magnetic reconnection
- 2012
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Ingår i: Journal of Geophysical Research. - 0148-0227 .- 2156-2202. ; 117, s. A07223-
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Tidskriftsartikel (refereegranskat)abstract
- A magnetic reconnection event with a moderate guide field encountered by Cluster in the near-Earth tail on 28 August 2002 is reported. The guide field points dawnward during this event. The quadrupolar structure of the Hall magnetic field within the ion diffusion region is distorted toward the northern hemisphere in the earthward part while toward the southern hemisphere tailward part of X-line. Observations of current density and electron pitch angle distribution indicate that the distorted quadrupolar structure is formed due to a deformed Hall electron current system. Cluster crossed the ion diffusion region from south to north earthward of the X-line. An electron density cavity is confirmed in the northern separatrix layer while a thin current layer (TCL) is measured in the southern separatrix layer. The TCL is formed due to electrons injected into the X-line along the magnetic field. These observations are different from simulation results where the cavity is produced associated with inflow electrons along the southern separatrix while the strong current sheet appears with the outflow electron beam along the northern separatrix. The energy of the inflowing electron in the separatrix layer could extend up to 10 keV. Energetic electron fluxes up to 50 keV have a clear peak in the TCL. The length of the separatrix layer is estimated to be at least 65 c/omega(pi). These observations suggest that electrons could be pre-accelerated before they are ejected into the X-line region along the separatrix. Multiple secondary flux ropes moving earthward are observed within the diffusion region. These secondary flux ropes are all identified earthward of the observed TCL. These observations further suggest there are numerous small scale structures within the ion diffusion region.
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| 6. |
- Wang, Rongsheng, et al.
(författare)
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Observation of double layer in the separatrix region during magnetic reconnection
- 2014
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Ingår i: Geophysical Research Letters. - 0094-8276 .- 1944-8007. ; 41:14, s. 4851-4858
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Tidskriftsartikel (refereegranskat)abstract
- We present in situ observation of double layer (DL) and associated electron measurement in the subspin time resolution in the separatrix region during reconnection for the first time. The DL is inferred to propagate away from the X line at a velocity of about ion acoustic speed and the parallel electric field carried by the DL can reach -20 mV/m. The electron displays a beam distribution inside the DL and streams toward the X line with a local electron Alfven velocity. A series of electron holes moving toward the X line are observed in the wake of the DL. The identification of multiple similar DLs indicates that they are persistently produced and therefore might play an important role in energy conversion during reconnection. The observation suggests that energy dissipation during reconnection can occur in any region where the DL can reach.
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| 7. |
- Wang, Rongsheng, et al.
(författare)
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Observation of multiple sub-cavities adjacent to single separatrix
- 2013
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Ingår i: Geophysical Research Letters. - : American Geophysical Union (AGU). - 0094-8276 .- 1944-8007. ; 40:11, s. 2511-2517
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Tidskriftsartikel (refereegranskat)abstract
- We investigate a direct south-north crossing of a reconnection ion diffusion region in the magnetotail. During this crossing, multiple electron density dips with a further density decrease within the cavity, called sub-cavities, adjacent to the northern separatrix are observed. The correlation between electron density sub-cavities and strong electric field fluctuations is obvious. Within one of the sub-cavities, a series of very strong oscillating perpendicular electric field and patchy parallel electric field are observed. The parallel electric field is nearly unipolar and directs away from X line. In the same region, inflow electrons with energy up to 100keV are injected into the X line. Based on the observations, we conclude that the high-energy inflowing electrons are accelerated by the patchy parallel electric field. Namely, electrons have been effectively accelerated while they are flowing into the X line along the separatrix. The observations indicate that the electron acceleration region is widely larger than the predicted electron diffusion region in the classical Hall magnetic reconnection model.
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| 8. |
- Wang, Xiaoyu, et al.
(författare)
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A Novel Output-Constrained Controller for DC/DC Buck Converter Feeding Constant Power Loads in DC Microgrids
- 2023
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Ingår i: IECON 2023 - 49th Annual Conference of the IEEE Industrial Electronics Society. - : Institute of Electrical and Electronics Engineers (IEEE).
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Konferensbidrag (refereegranskat)abstract
- DC microgrids have emerged as a promising solution for efficient and reliable electricity distribution. In DC microgrids, when power electronic loads and motor drives are tightly regulated, they behave as constant power loads (CPLs) and may lead to the instability issue. In this paper, a novel output-constrained controller for the DC/DC buck converter feeding CPLs is proposed. By introducing the output-constrained technique into the backstepping method, the proposed control scheme can keep the DC bus working within the pre-specific boundary even when large-signal disturbances happen. Relevant theoretical analyses are conducted by employing Laypunov stability theorem. Simulations in Matlab/Simulink are presented to verify the proposed controller.
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