| 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. |
- Qu, Minni, et al.
(författare)
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Charge-Injection-Induced Time Decay in Carbon Nanotube Network-Based FETs
- 2010
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Ingår i: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 31:10, s. 1098-1100
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Tidskriftsartikel (refereegranskat)abstract
- A voltage-pulse method is utilized to investigate the charge-injection-induced time decay of the source-drain current of field-effect transistors with randomly networked single-walled carbon nanotubes (CNTs) as the conduction channel. The relaxation of trapped carriers in the CNT networks can be accounted for by assuming two exponential decays occurring simultaneously. The slow decay is characterized by a time constant comparable to literature data obtained for a carrier recombination in the semiconducting CNTs. The faster decay with a time constant that has a smaller order of magnitude is attributed to the annihilation of trapped carriers in metallic CNTs or at metal-CNT contacts. Both time constants are gate-bias dependent.
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| 3. |
- Chen, Si, et al.
(författare)
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A graphene field-effect capacitor sensor in electrolyte
- 2012
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 101:15, s. 154106-
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Tidskriftsartikel (refereegranskat)abstract
- The unique electronic properties of graphene are exploited for field-effect sensing in both capacitor and transistor modes when operating the sensor device in electrolyte. The device is fabricated using large-area graphene thin films prepared by means of layer-by-layer stacking. Although essentially the same device, its operation in the capacitor mode is found to yield more information than in the transistor mode. The capacitor sensor can simultaneously detect the variations of surface potential and electrical-double-layer capacitance at the graphene/electrolyte interface when altering the ion concentration. The capacitor-mode operation further facilitates studies of the molecular binding-adsorption kinetics by monitoring the capacitance transient
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| 4. |
- Chen, Zhi-Hui, et al.
(författare)
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Comb-shaped photonic crystal structure for efficient broadband light diffraction and funnelling in solar cells
- 2012
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Ingår i: Solar Energy Materials and Solar Cells. - : Elsevier BV. - 0927-0248 .- 1879-3398. ; 99, s. 316-320
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Tidskriftsartikel (refereegranskat)abstract
- We present a comb-shaped photonic-crystal (PhC) rods-lattice structure of broadband light diffraction and funnelling for solar cell applications. It is shown that the photonic band of this PhC structure is very dispersive over a broad bandwidth so that light will be efficiently diffracted in the wavelength region of solar radiation. The PhC structure also creates resonance modes leading to further diffraction and funnelling of light so that the light propagates in many pathways in the whole PhC lattice region, which will greatly facilitate light-matter interaction when light-absorbing elements are embedded in the PhC structure. The proposed structure is also valid for photodetection applications.
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| 5. |
- Chen, Zhi-Hui, et al.
(författare)
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Enhanced normal-direction excitation and emission of dual-emitting quantum dots on a cascaded photonic crystal surface
- 2014
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Ingår i: Nanoscale. - : Royal Society of Chemistry (RSC). - 2040-3364 .- 2040-3372. ; 6:24, s. 14708-14715
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Tidskriftsartikel (refereegranskat)abstract
- Large normal-direction excitation and emission of dual-emitting quantum dots (QDs) are essential for practical application of QD sensors based on the ratiometric fluorescence response. We have numerically demonstrated an all-dielectric four-layer cascaded photonic crystal (CPC) structure (alternating TiO2 and SiO2/SU8 layers with two dimensional nanoscale patterns in each layer) which is capable of providing normal-direction high Q-factor leaky modes at excitation wavelengths of QDs and two low Q-factor leaky modes coinciding with the two emission peaks of a dual-emitting QD. Normal-direction excitation and far-field emission of the dual-emitting QDs are enhanced significantly when QDs are distributed on/in the top TiO2 layer of the CPC structure, especially in the spatial distribution areas of the resonant leaky modes. QDs can be positioned differently depending on the applications. Positioning QDs on the top TiO2 layer will improve the signal-to-noise ratios of QD biomedical/chemical/temperature sensors, while embedding QDs in the top TiO2 layer will increase the light extraction from the QD light emitting device, making our CPC a versatile optical coupling structure. Our CPC-QD structure is experimentally feasible and robust against the parameter perturbation in real fabrication.
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| 6. |
- Ge, Yue, et al.
(författare)
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Environmental OMICS: Current Status and Future Directions
- 2013
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Ingår i: JOURNAL OF INTEGRATED OMICS. - : Proteomass Scientific Society. - 2182-0287. ; 3:2, s. 75-87
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Tidskriftsartikel (refereegranskat)abstract
- Applications of OMICS to high throughput studies of changes of genes, RNAs, proteins, metabolites, and their associated functionsin cells or organisms exposed to environmental chemicals has led to the emergence of a very active research field: environmental OMICS.This developing field holds an important key for improving the scientific basis for understanding the potential impacts of environmentalchemicals on both health and the environment. Here we describe the state of environmental OMICS with an emphasis on its recent accomplishmentsand its problems and potential solutions to facilitate the incorporation of OMICS into mainstream environmental and healthresearch.Data sources: We reviewed relevant and recently published studies on the applicability and usefulness of OMICS technologies to the identificationof toxicity pathways, mechanisms, and biomarkers of environmental chemicals for environmental and health risk monitoring andassessment, including recent presentations and discussions on these issues at The First International Conference on Environmental OMICS(ICEO), held in Guangzhou, China during November 8-12, 2011. This paper summarizes our review.Synthesis: Environmental OMICS aims to take advantage of powerful genomics, transcriptomics, proteomics, and metabolomics tools toidentify novel toxicity pathways/signatures/biomarkers so as to better understand toxicity mechanisms/modes of action, to identify/categorize/prioritize/screen environmental chemicals, and to monitor and predict the risks associated with exposure to environmental chemicalson human health and the environment. To improve the field, some lessons learned from previous studies need to be summarized, aresearch agenda and guidelines for future studies need to be established, and a focus for the field needs to be developed.Conclusions: OMICS technologies for identification of RNA, protein, and metabolic profiles and endpoints have already significantly improvedour understanding of how environmental chemicals affect our ecosystem and human health. OMICS breakthroughs are empoweringthe fields of environmental toxicology, chemical toxicity characterization, and health risk assessment. However, environmental OMICS is stillin the data generation and collection stage. Important data gaps in linking and/or integrating toxicity data with OMICS endpoints/profilesneed to be filled to enable understanding of the potential impacts of chemicals on human health and the environment. It is expected thatfuture environmental OMICS will focus more on real environmental issues and challenges such as the characterization of chemical mixturetoxicity, the identification of environmental and health biomarkers, and the development of innovative environmental OMICS approachesand assays. These innovative approaches and assays will inform chemical toxicity testing and prediction, ecological and health risk monitoringand assessment, and natural resource utilization in ways that maintain human health and protects the environment in a sustainable manner.
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| 7. |
- Hao, Dong-Xia, et al.
(författare)
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Residue-level elucidation of the ligand-induced protein binding on phenyl-argarose microspheres by NMR hydrogen/deuterium exchange technique
- 2012
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Ingår i: Soft Matter. - : Royal Society of Chemistry (RSC). - 1744-683X .- 1744-6848. ; 8:23, s. 6248-6255
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Tidskriftsartikel (refereegranskat)abstract
- Protein-ligand interactions on liquid-solid interfaces governed the design of functional biomaterials. However, accurate residue details of ligand induced protein binding and unfolding on an interface were still unknown by the current ensemble of protein structure characterizations. Here, a hydrogen/deuterium (H/D) approach coupled with analysis of NMR TOCSY spectra and the solvent accessible surface area (SASA) was designed to enable residue level understanding of lysozyme adsorbed at a phenyl-ligand modified surface. Results showed that the binding sites and unfolding of lysozyme molecules on phenyl-agarose microspheres demonstrated significant ligand-density dependence and protein-coverage dependence. Either increasing ligand density or decreasing adsorption coverage would lead to more binding sites and unfolding of the protein molecules. With the multipoint adsorption strengthening, the protein molecule changed from lying end-on to side-on. Finally, Molecular Dock simulation was utilized to evaluate the NMR determined binding sites based on energy ranking of the binding. It confirmed that this NMR approach represents a reliable route to in silico abundant residue-level structural information during protein interaction with biomaterials.
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| 8. |
- Liu, Zhiying, et al.
(författare)
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Hysteresis-free thin-film transistors achieved by novel solution-processing of nanotubes/polymer composites
- 2012
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Ingår i: Materials Research Society Spring Meeting 2012, San Francisco, April 9-13, 2012..
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Konferensbidrag (refereegranskat)abstract
- Thin-film transistors (TFTs) based on single-walled carbon nanotubes (SWCNTs) have gained enormous attention in the community of flexible/stretchable electronics. At present, such TFTs often suffer from severe problems including giant hysteresis in their transfer characteristics. With SiO2 as the gate dielectric, extensive investigations have led to generally accepted understanding of the hysteresis as being caused by charge transfer between the SWCNTs and their surroundings including both water molecules bound on the SiO2 surface (Si≡OH) and the water/oxygen molecules in the ambient atmosphere. In order to combat the hysteresis issue, significant efforts have been made by annealing the TFTs in vacuum and separating SWCNTs from SiO2 by deposition of a self-assembled monolayer (SAM) on the SiO2 or passivating the SWCNTs with an organic or inorganic dielectric film. These methods, however, require either processing in inert environment or developing elaborated processes. In the present work, we demonstrate hysteresis-free TFTs based on SWCNT/polymer composite without any complex treatment. The composite consists of SWCNTs and poly-9,9_dioctyl-fluorene-co-bithiophene (F8T2). With the aid of polymer F8T2, SWCNTs can be efficiently dissolved in commonly used solvents thereby forming a uniform composite solution. By soaking a chip with predefined TFT structures on an oxidized Si substrate in the composite solution, direct assembly of the composite on the SiO2 occurs, leading to the formation of a composite thin film in the channel region of the TFTs. Although fabricated using a very simple process, our TFTs exhibit hysteresis-free operation under ambient conditions. It is plausible to suggest that SWCNTs are embedded in the F8T2 matrix with the latter providing an effective shield for the former against the trap sites on the SiO2 and the H2O/O2 molecules in the atmosphere. In comparison to the other reported means aiming at hysteresis reduction, the present method is simple, robust, solution processable, effective, and operable under ambient conditions. In addition, we have found F8T2 to preferentially disperse semiconducting SWCNTs rendering a selective removal of the metallic species in the solution. This selectivity is of paramount importance as it results in high-performance TFTs with both high on-state current (0.1 µA/µm @ channel length = 50 µm) and large on/off current ratio (103-105). The TFTs have also shown significantly improved uniformity and dimensional scalability with a mobility value of 10-20 cm2V-1s-1, which have allowed us to investigate the TFTs using the resultant logic circuits.
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| 9. |
- Liu, Zhiying, et al.
(författare)
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SMALL-Hysteresis Thin-Film Transistors Achieved by Facile Dip-Coating of Nanotube/Polymer Composite
- 2012
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Ingår i: Advanced Materials. - : Wiley. - 0935-9648 .- 1521-4095. ; 24:27, s. 3633-3638
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Tidskriftsartikel (refereegranskat)abstract
- Small-hysteresis, high-performance thin-film transistors (TFTs) are readily realized simply by dip-coating of a solution-processable composite. The composite consists of single-walled carbon nanotubes (SWCNTs) embedded in semiconducting polymer used as the channel material. The resultant TFTs simultaneously exhibit large on/off current ratio, high on-current level, high mobility in the range 10−20 cm2V−1s−1, and good uniformity and scalability.
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| 10. |
- Lu, Hui, et al.
(författare)
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Grain growth behavior, surface morphology evolution, structures, and optical properties of ZnO thin films prepared by RF reactive magnetron sputtering
- 2014
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Ingår i: Journal of Optoelectronics and Advanced Materials. - : NATL INST OPTOELECTRONICS. - 1454-4164 .- 1841-7132. ; 16:1-2, s. 170-175
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Tidskriftsartikel (refereegranskat)abstract
- ZnO thin films were prepared by radio frequency (RF) reactive magnetron sputtering at varying deposition conditions. The effects of RF power (from 40 to 90 W) and substrate temperature (from 100 to 200 degrees C) on the grain growth behavior, surface morphology evolution, and the structural and optical properties of the films were investigated. Atomic force microscopy (AFM) measurements confirmed that the grain size and surface roughness depend mainly on the RF power and increase with increasing it at the initial deposition stage of 5 s, and are strongly affected by the substrate temperature and increase with increasing it at the final deposition stage of 45 min. The influence of both the deposition parameters on the surface structure of the ZnO films at different deposition stages and the mechanism concerning this influence were discussed. The X-ray diffraction (XRD) and optical absorption spectra analysis indicated that all the films deposited for 45 min are in the state of the compressive stress and exhibit polycrystalline nature with the (002) preferential orientation, and they have high optical transparency in the visible range and sharp absorption edges around the wavelength 360 nm corresponding to the ZnO exciton. With the increase of the RF power and substrate temperature, the grain size increases, the residual compressive stress relaxes, and the optical band gaps broaden. In comparison with the RF power, the substrate temperature has more evident influence on the microstructure of the ZnO thin films.
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| 11. |
- Zhang, Chao-Zhi, et al.
(författare)
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NONLINEAR OPTICAL PROPERTIES OF NOVEL AND EFFECTIVE H-SHAPED CHROMOPHORES CONTAINING THREE PARALLEL AND NON-CONJUGATED D-pi-A UNITS
- 2011
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Ingår i: Journal of nonlinear optical physics and materials. - 0218-8635. ; 20:3, s. 327-339
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Tidskriftsartikel (refereegranskat)abstract
- H-shaped chromophores containing three parallel non-conjugated D-pi-A units are effective chromophores with high hyperpolarizability and good optical transparency. The semi-empirical methods ZINDO, AM1, MNDO and PM3 were employed to study the effect of strength of acceptors and donors, and steric repulsion between substituents on static first hyperpolarizabilities (beta(0)) and enhancements of beta(0) of the H-shaped chromophores. The results show that the H-shaped chromophore would exhibit the largest beta(0) and/or the largest enhancement of beta(0) of the chromophore when combination of a donor (D) and an acceptor (A) in a D-pi-A unit is suitable.
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| 12. |
- Zhang, Chao-Zhi, et al.
(författare)
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Theoretical study of macroscopic optical nonlinearities of "parallel connection" chromophores containing PNA units
- 2013
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Ingår i: Journal of nonlinear optical physics and materials. - 0218-8635. ; 22:2, s. 1350014-
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Tidskriftsartikel (refereegranskat)abstract
- The semi-empirical method ZINDO was employed to study relationship between macroscopic optical nonlinear parameter mu beta/MW (where mu is the dipole moment, beta is the first hyperpolarizability, and MW is molecular weight) and the number of parallel non-conjugated D-pi-A units in a chromophore. The computational results show that macroscopic optical nonlinear parameter mu beta/MW value increases remarkably from 1.64 to 2.53 with increasing the number of parallel and non-conjugated p-Nitroaniline (PNA) units in a chromophore from 1 to 3. Then the mu beta/MW value decreases rapidly from 2.53 to 0.43 with increasing the number of PNA units in a chromophore from 3 to 5. It suggests that design of chromophores containing two or three parallel non-conjugated D-pi-A units would be an effective strategy for increasing the first hyperpolarizability and macroscopic optical nonlinearity of designed NLO materials.
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| 13. |
- Zhang, Fei, et al.
(författare)
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Perivascular macrophage-like melanocyte responsiveness to acoustic trauma--a salient feature of strial barrier associated hearing loss
- 2013
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Ingår i: The FASEB Journal. - : Federation of American Societies for Experimental Biology. - 0892-6638 .- 1530-6860. ; 27:9, s. 3730-3740
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Tidskriftsartikel (refereegranskat)abstract
- Tissue perivascular resident macrophages (PVM/Ms), a hybrid cell type with characteristics of both macrophages and melanocytes, are critical for establishing and maintaining the endocochlear potential (EP) required for hearing. The PVM/Ms modulate expression of tight- and adherens-junction proteins in the endothelial barrier of the stria vascularis (intrastrial fluid-blood barrier) through secretion of a signaling molecule, pigment epithelium growth factor (PEDF). Here, we identify a significant link between abnormalities in PVM/Ms and endothelial barrier breakdown from acoustic trauma to the mouse ear. We find that acoustic trauma causes activation of PVM/Ms and physical detachment from capillary walls. Concurrent with the detachment, we find loosened tight junctions between endothelial cells and decreased production of tight- and adherens-junction protein, resulting in leakage of serum proteins from the damaged barrier. A key factor in the intrastrial fluid-blood barrier hyperpermeability exhibited in the mice is down-regulation of PVM/M modulated PEDF production. We demonstrate that delivery of PEDF to the damaged ear ameliorates hearing loss by restoring intrastrial fluid-blood barrier integrity. PEDF up-regulates expression of tight junction-associated proteins (ZO-1 and VE-cadherin) and PVM/M stabilizing neural cell adhesion molecule (NCAM-120). These studies point to the critical role PVM/Ms play in regulating intrastrial fluid-blood barrier integrity in healthy and noise-damaged ears.
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| 14. |
- Zhang, Hong-Zhen, et al.
(författare)
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PINCH Protein Expression in Normal Endometrium, Atypical Endometrial Hyperplasia and Endometrioid Endometrial Carcinoma
- 2010
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Ingår i: CHEMOTHERAPY. - : S. Karger AG. - 0009-3157 .- 1421-9794. ; 56:4, s. 291-297
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Tidskriftsartikel (refereegranskat)abstract
- Background: Particularly interesting new cysteine-histidine rich protein ( PINCH), as an adapter protein of the LIM family for signal transduction in the integrin and growth factor pathway, is upregulated in the stroma of several common types of cancers and involved in promoting tumor progression. In the present study, we examined PINCH expression in normal endometrium, atypical endometrial hyperplasia and endometrioid carcinoma, and further studied the relationships of PINCH expression with clinicopathological variables in cancer patients. Methods: PINCH expression was examined by immunohistochemistry in 23 normal endometrial samples, 18 atypical endometrial hyperplasias and 48 endometrioid endometrial carcinomas. Results: The PINCH expression in the stroma of cancer (71%) was significantly increased compared to either normal endometrium (17%, p andlt; 0.0001) or atypical hyperplasia (39%, p = 0.017), along with 9 cancers that had stronger PINCH expressions at the invasive margin of the cancers compared to the inner cancers. PINCH expression in cancer was higher in the patients with hypertension (p = 0.041) and estrogen exposure time andgt;30 years (p = 0.021). On the other hand, PINCH expression was not related to menopausal status, gravid status, blood sugar/lipid, family background of cancer, histological grade, myometrial invasion, cervical involvement, lymph nodal metastases, growth pattern, estrogen and progestogen receptors (p andgt; 0.05). Conclusion: The results suggest that PINCH seems to play a role, presently unknown, in the tumorigenesis and development of endometrial cancer that merits further study.
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| 15. |
- Zhao, Xi, et al.
(författare)
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Preparation of uniform and large sized agarose microspheres by an improved membrane emulsification technique
- 2014
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Ingår i: Powder Technology. - : Elsevier BV. - 0032-5910 .- 1873-328X. ; 253, s. 444-452
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Tidskriftsartikel (refereegranskat)abstract
- The SPG (Shirasu porous-glass) membrane emulsification technique has been subject to much attention for the preparation of uniform emulsions. However, so far primarily used for the production of droplets with sizes below approximately 60 mu m. A production bottleneck occurred if the desired size was further increased, especially when highly viscous dispersed phases were involved. To this end, an improved membrane emulsification technique was proposed and has been applied to the preparation of large agarose microspheres, with a size of around 90 mu m and with a narrow size distribution. The effects of important emulsification parameters, including the pore size of the SPG membrane, the operating pressure, the stirring rate of the continuous phase, the composition of the continuous oil phase, and the concentration of agarose in the dispersed water phase, have been extensively studied. Under optimum conditions, uniform-size agarose microspheres with an average diameter of 93 pm and a size distribution index of 0.65 were successfully prepared. The average particle size of the home-made agarose microspheres was almost identical to that of the commercial product Sepharose 4 Fast Flow (4FF), which is produced by mechanical stirring and an additional sieving process. However, the size distribution of the former was much narrower than that of the latter. Therefore, the improved membrane emulsification technique presented here is promising for the application of high viscosity systems such as agarose solutions, and the production scale can be further enhanced by increasing the number of membrane units attached to the experimental apparatus. (C) 2013 Elsevier B.V. All rights reserved.
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