| 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. |
- You, Lei, et al.
(författare)
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A Performance Study of Energy Minimization for Interleaved and Localized FDMA
- 2014
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Ingår i: 2014 IEEE 19TH INTERNATIONAL WORKSHOP ON COMPUTER AIDED MODELING AND DESIGN OF COMMUNICATION LINKS AND NETWORKS (CAMAD). - : IEEE. - 9781479957255 ; , s. 16-20
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Konferensbidrag (refereegranskat)abstract
- Optimal channel allocation is a key performance engineering aspect in single-carrier frequency-division multiple access (SC-FDMA). It is of significance to consider minimum sum power (Min-Power), subject to meeting specified users demand, since mobile users typically employ battery-powered handsets. In this paper, we prove that Min-Power is polynomial-time solvable for interleaved SC-FDMA (IFDMA). Then we propose a channel allocation algorithm for IFDMA, which is guaranteed to achieve global optimum in polynomial time. We numerically compare the proposed algorithm with optimal localized SC-FDMA (LFDMA) for Min-Power. The results show that LFDMA outperforms IFDMA in the maximal supported user demand. When the user demand can be satisfied in both LFDMA and IFDMA, LFDMA performs slightly better than IFDMA. However MinPower is polynomial-time solvable for IFDMA whereas it is not for LFDMA.
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| 3. |
- He, Shu-Lan, et al.
(författare)
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Mitochondrial-related gene expression profiles suggest an important role of PGC-1alpha in the compensatory mechanism of endemic dilated cardiomyopathy.
- 2013
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Ingår i: Experimental Cell Research. - : Elsevier. - 0014-4827 .- 1090-2422. ; 319:17, s. 2604-2616
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Tidskriftsartikel (refereegranskat)abstract
- Keshan disease (KD) is an endemic dilated cardiomyopathy with unclear etiology. In this study, we compared mitochondrial-related gene expression profiles of peripheral blood mononuclear cells (PBMCs) derived from 16 KD patients and 16 normal controls in KD areas. Total RNA was isolated, amplified, labeled and hybridized to Agilent human 4 × 44k whole genome microarrays. Mitochondrial-related genes were screened out by the Third-Generation Human Mitochondria-Focused cDNA Microarray (hMitChip3). Quantitative real-time PCR, immunohistochemical and biochemical parameters related mitochondrial metabolism were conducted to validate our microarray results. In KD samples, 34 up-regulated genes (ratios ≥ 2.0) were detected by significance analysis of microarrays and ingenuity systems pathway analysis (IPA). The highest ranked molecular and cellular functions of the differentially regulated genes were closely related to amino acid metabolism, free radical scavenging, carbohydrate metabolism, and energy production. Using IPA, 40 significant pathways and four significant networks, involved mainly in apoptosis, mitochondrion dysfunction, and nuclear receptor signaling were identified. Based on our results, we suggest that PGC-1alpha regulated energy metabolism and anti-apoptosis might play an important role in the compensatory mechanism of KD. Our results may lead to the identification of potential diagnostic biomarkers for KD in PBMCs, and may help to understand the pathogenesis of KD.
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| 4. |
- You, Lei, et al.
(författare)
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Cross-layer optimisation for uplink transmission in OFDMA cellular networks with fixed relays
- 2011
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Ingår i: European transactions on telecommunications. - : John Wiley & Sons. - 1124-318X .- 2161-3915. ; 22:6, s. 296-314
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we consider a cross-layer design aimed to enhance performance for uplink transmission in an orthogonal frequency division multiple-access (OFDMA)-based cellular network with fixed relay stations. Because mobile stations (MSs) spend most of the power on the uplink transmission, power efficiency resource allocation becomes very important to MSs. We develop a cross-layer optimisation framework for two types of uplink flows (inelastic and elastic flows) that have different quality-of-service requirements. For inelastic flows with fixed-rate requirement, we formulate the cross-layer optimisation problem as the minimisation of the sum transmission power of MSs under the constraints of flow conservation law, subcarrier assignment, relaying path selection and power allocation. For elastic flows with flexible-service-rate requirement, we consider the cross-layer trade-off between uplink service rate and power consumption of MSs and pose the optimisation problem as the maximisation of a linear combination of utility (of service rates) and power consumption (of MSs). Different trade-offs can be achieved by varying the weighting parameters. Dual decomposition and subgradient methods are used to solve the problems optimally with reduced computational complexity. The simulation results show that, through the proposed cross-layer resource optimisation framework and algorithms, significant benefits of deployment of multiple fixed relays in an OFDMA cellular network can be fully obtained such as reduction in power consumption, increase in service rate and energy savings in the uplink transmission of MSs.
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| 5. |
- You, Lei, et al.
(författare)
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Cross-layer optimization of wireless multihop networks with one-hop two-way network coding
- 2011
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Ingår i: Computer Networks. - : Elsevier BV. - 1389-1286 .- 1872-7069. ; 55:8, s. 1747-1769
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we investigate optimal cross-layer design of congestion control, routing, one-hop two-way inter-commodity (OTIC) network coding and scheduling in wireless multihop networks utilizing the broadcast advantage of wireless medium. We first present an achievable rate region with OTIC network coding by introducing virtual flow rates in a node. Then we formulate the network utility maximization problem subject to constraints on this achievable rate region, and analyze the complexities of both node- and path-based formulation with no network coding, OTIC network coding, and overhearing network coding. After that, we solve it using dual decomposition and subgradient method. Based on the solution, we present a new queue model, which is able to facilitate the coding operation between two-way commodities, and then propose a backpressure-based cross-layer optimization algorithm with low coding complexity and overhead. Afterwards, we analyze the stability and asymptotical optimality of the proposed cross-layer algorithm by Lyapunov drift technique, and evaluate its performance through extensive simulation. By comparing with the pure routing scheme under both primary and two-hop interference models in an illustrative topology, it is shown that with the proposed joint optimization algorithms, the OTIC network coding can interact adaptively and optimally with other components in different layers and achieve high throughput gain. Simulation of the proposed algorithm in a mesh network with base station and a random ad hoc network justifies that OTIC network coding can obtain considerable throughput gain with low complexity in various kinds of networks.
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