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Wang HQ, Xu GS, Wan BN, Ding SY, Guo HY, Shao LM, Liu SC, Xu XQ, Wang E, Yan N, Naulin V, Nielsen AH, Rasmussen JJ, Candy J, Bravenec R, Sun YW, Shi TH, Liang YF, Chen R, Zhang W, Wang L, Chen L, Zhao N, Li YL, Liu YL, Hu GH, Gong XZ. New edge coherent mode providing continuous transport in long-pulse H-mode plasmas. PHYSICAL REVIEW LETTERS 2014; 112:185004. [PMID: 24856704 DOI: 10.1103/physrevlett.112.185004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Indexed: 06/03/2023]
Abstract
An electrostatic coherent mode near the electron diamagnetic frequency (20-90 kHz) is observed in the steep-gradient pedestal region of long pulse H-mode plasmas in the Experimental Advanced Superconducting Tokamak, using a newly developed dual gas-puff-imaging system and diamond-coated reciprocating probes. The mode propagates in the electron diamagnetic direction in the plasma frame with poloidal wavelength of ∼8 cm. The mode drives a significant outflow of particles and heat as measured directly with the probes, thus greatly facilitating long pulse H-mode sustainment. This mode shows the nature of dissipative trapped electron mode, as evidenced by gyrokinetic turbulence simulations.
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Hong ZY, Zhai W, Yan N, Wei B. Measurement and simulation of acoustic radiation force on a planar reflector. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 135:2553-2558. [PMID: 24815239 DOI: 10.1121/1.4869678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The accurate calculation of the acoustic radiation force is important for ultrasonic application techniques. Usually, the acoustic radiation force can be divided into the near-field and the far-field force according to the ratio of the emitter-reflector distance to the wavelength. In this study, appropriate theories and methods are explored to simulate the far-field and the near-field acoustic radiation force exerted on a planar reflector. The comparison between simulation and experiment indicates that the far-field force is not sensitive to the boundary shape and size while the near-field force is highly sensitive to the boundary size. Only the acoustic model with the minimized boundary size could yield the near-field force consistent with the experiment. Further calculations reveal that the far-field force first increases and then decreases with the rise of the reflector radius, and that the near-field force fluctuates with the acoustic frequency, especially when the emitter-reflector distance is very small. The near-field repulsive force can be changed into the attractive force when the acoustic frequency is lowered.
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Stockdale A, Tipping E, Lofts S, Fott J, Garmo OA, Hruska J, Keller B, Löfgren S, Maberly SC, Majer V, Nierzwicki-Bauer SA, Persson G, Schartau AK, Thackeray SJ, Valois A, Vrba J, Walseng B, Yan N. Metal and proton toxicity to lake zooplankton: a chemical speciation based modelling approach. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2014; 186:115-125. [PMID: 24370669 DOI: 10.1016/j.envpol.2013.11.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 11/18/2013] [Accepted: 11/26/2013] [Indexed: 06/03/2023]
Abstract
The WHAM-FTOX model quantifies the combined toxic effects of protons and metal cations towards aquatic organisms through the toxicity function (FTOX), a linear combination of the products of organism-bound cation and a toxic potency coefficient for each cation. We describe the application of the model to predict an observable ecological field variable, species richness of pelagic lake crustacean zooplankton, studied with respect to either acidification or the impacts of metals from smelters. The fitted results give toxic potencies increasing in the order H(+) < Al < Cu < Zn < Ni. In general, observed species richness is lower than predicted, but in some instances agreement is close, and is rarely higher than predictions. The model predicts recovery in agreement with observations for three regions, namely Sudbury (Canada), Bohemian Forest (Czech Republic) and a subset of lakes across Norway, but fails to predict observed recovery from acidification in Adirondack lakes (USA).
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Lavorgna M, Buonocore GG, Tescione F, Capezzuto F, Yan N, Amendola E. Multifunctional chitosan nanocomposites: The effect of silver supported on montmorillonite platelets on barrier and mechanical properties. ACTA ACUST UNITED AC 2014. [DOI: 10.1063/1.4876873] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Hao JJ, Chen HL, Ren CL, Yan N, Geng HJ, Chen XG. Synthesis of superparamagnetic Fe3O4 nanocrystals in reverse microemulsion at room temperature. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/143307510x12777574295307] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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Wang W, Dai LX, Zhang S, Yang Y, Yan N, Fan P, Dai L, Tian HW, Cheng L, Zhang XM, Li C, Zhang JF, Xu F, Shi G, Chen XL, Du T, Li YM, Wei YQ, Deng HX. Regulation of epidermal growth factor receptor signaling by plasmid-based microRNA-7 inhibits human malignant gliomas growth and metastasis in vivo. Neoplasma 2013; 60:274-83. [PMID: 23373996 DOI: 10.4149/neo_2013_036] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
MicroRNAs are endogenous, non-coding RNAs of approximately 20-22 nucleotides that regulate genes expression by binding to the 3' untranslated region (UTR) of targets mRNAs and play critical roles in cancer pathways. Malignant glioma is the most common and highly lethal central nervous system tumor for which little effective treatment is available over several decades. The purpose of this study was to explore the therapeutic potential of plasmid-based microRNA-7 (miR-7) for gliomas in vivo. Enhancing miR-7 levels in vitro could significantly induce cell apoptosis, and inhibit cell proliferation, cell migration and invasion. Western blotting analysis was performed, which indicated that miR-7 directly inhibited epidermal growth factor receptor (EGFR) and further antagonized the downstream protein kinases including ERK, Akt and Stat3. Furthermore, systemic administration of miR-7 encapsulated in cationic liposome resulted in glioma xenografts growth arrest and the metastatic nodules decrease effectively in a sequence-specific manner. In this study, miR-7 was applied in glioma treatment for the first time in vivo. Our findings suggested that the plasmid-mediated gene therapy with miR-7 appeared to be a promising candidate for the development of new antitumor and anti-metastasis treatment for human glioma.
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Liang Y, Gong XZ, Gan KF, Gauthier E, Wang L, Rack M, Wang YM, Zeng L, Denner P, Wingen A, Lv B, Ding BJ, Chen R, Hu LQ, Hu JS, Liu FK, Jie YX, Pearson J, Qian JP, Shan JF, Shen B, Shi TH, Sun Y, Wang FD, Wang HQ, Wang M, Wu ZW, Zhang SB, Zhang T, Zhang XJ, Yan N, Xu GS, Guo HY, Wan BN, Li JG. Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak. PHYSICAL REVIEW LETTERS 2013; 110:235002. [PMID: 25167503 DOI: 10.1103/physrevlett.110.235002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2013] [Indexed: 06/03/2023]
Abstract
Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.
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Yan N, Liu X, Zhang L, Zhang Z, Han X. The amount of Ge tunes the atomic structure of amorphous GexTe1−x alloy. Chem Phys Lett 2013. [DOI: 10.1016/j.cplett.2012.11.067] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Liu SC, Shao LM, Zweben SJ, Xu GS, Guo HY, Cao B, Wang HQ, Wang L, Yan N, Xia SB, Zhang W, Chen R, Chen L, Ding SY, Xiong H, Zhao Y, Wan BN, Gong XZ, Gao X. New dual gas puff imaging system with up-down symmetry on experimental advanced superconducting tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:123506. [PMID: 23277986 DOI: 10.1063/1.4770122] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Gas puff imaging (GPI) offers a direct and effective diagnostic to measure the edge turbulence structure and velocity in the edge plasma, which closely relates to edge transport and instability in tokamaks. A dual GPI diagnostic system has been installed on the low field side on experimental advanced superconducting tokamak (EAST). The two views are up-down symmetric about the midplane and separated by a toroidal angle of 66.6°. A linear manifold with 16 holes apart by 10 mm is used to form helium gas cloud at the 130×130 mm (radial versus poloidal) objective plane. A fast camera is used to capture the light emission from the image plane with a speed up to 390,804 frames/s with 64×64 pixels and an exposure time of 2.156 μs. The spatial resolution of the system is 2 mm at the objective plane. A total amount of 200 Pa.L helium gas is puffed into the plasma edge for each GPI viewing region for about 250 ms. The new GPI diagnostic has been applied on EAST for the first time during the recent experimental campaign under various plasma conditions, including ohmic, L-mode, and type-I, and type-III ELMy H-modes. Some of these initial experimental results are also presented.
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Yang Y, Zhang XM, Zhang N, Cheng L, Li C, Zhang S, Zhang JF, Dai L, Tian HW, Yan N, Fan P, Dai LX, Xu F, Shi G, Chen XL, Du T, Li YM, Wei YQ, Deng HX. IL15 combined with Caspy2 provides enhanced therapeutic efficiency against murine malignant neoplasm growth and metastasis. Cancer Gene Ther 2012; 19:460-7. [DOI: 10.1038/cgt.2012.17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Fan P, Zhang S, Tian H, Yan N, Dai L, Zhang X, Cheng L, Li C, Li Y, Chen X, Shi G, Yang Y, Wei Y, Deng H. Enhanced chemosensitivity to CPT-11 in colorectal carcinoma xenografts by small hairpin RNA interference targeting PLK1. Neoplasma 2012; 59:676-84. [PMID: 22862168 DOI: 10.4149/neo_2012_086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Commonly used drugs for the treatment of colon{} cancer patients like CPT-11 shows severe side effects or induces resistance in clinical settings. Thus, we analyzed a combination of PLK1 (polo-like kinase 1)-specific short hair RNA (shRNA), a potent tool to destroy mitosis in cancer cells, together with CPT-11 to enhance drug sensitivity. Cellular proliferation and apoptosis were determined in SW620 colorectal carcinoma cells. Knockdown of cellular PLK1 led to the decreased mRNA and PLK1 protein in RT-PCR and western blot assay. The viability declined (p<0.001) in MTT assay and colony formation assay, and the number of apoptotic cells was clearly increased (p<0.01) in flow cytometric analysis and Hoechst 33258 staining compared with control cells after incubation with PLK1-specific shRNA and SN-38. We found the level of cleaved PARP was also increased in vitro. In vivo, employment of shRNA targeting PLK1 improved the sensitivity to treat SW620 nude mouse model toward CPT-11. The combination therapy inhibited cellular proliferation and promoted apoptosis observed at the percentage of PCNA and caspase3 by immunohistochemistry, accompanied with TUNEL assay. As we expect, the combination treatment delayed tumor growth (p<0.01) and simultaneously reduced tumor weight (p<0.01) compared with control group. Taken together, combination of PLK1-specific shRNA interference with low-dose CPT-11 triggered a antitumor efficacy and represented a potential strategy to treat colon cancer.
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Xu GS, Wan BN, Wang HQ, Guo HY, Zhao HL, Liu AD, Naulin V, Diamond PH, Tynan GR, Xu M, Chen R, Jiang M, Liu P, Yan N, Zhang W, Wang L, Liu SC, Ding SY. First evidence of the role of zonal flows for the L-H transition at marginal input power in the EAST tokamak. PHYSICAL REVIEW LETTERS 2011; 107:125001. [PMID: 22026773 DOI: 10.1103/physrevlett.107.125001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Indexed: 05/31/2023]
Abstract
A quasiperiodic Er oscillation at a frequency of <4 kHz, much lower than the geodesic-acoustic-mode frequency, with a modulation in edge turbulence preceding and following the low-to-high (L-H) confinement mode transition, has been observed for the first time in the EAST tokamak, using two toroidally separated reciprocating probes. Just prior to the L-H transition, the Er oscillation often evolves into intermittent negative Er spikes. The low-frequency Er oscillation, as well as the Er spikes, is strongly correlated with the turbulence-driven Reynolds stress, thus providing first evidence of the role of the zonal flows in the L-H transition at marginal input power. These new findings not only shed light on the underlying physics mechanism for the L-H transition, but also have significant implications for ITER operations close to the L-H transition threshold power.
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Potapov A, Muirhead J, Yan N, Lele S, Lewis M. Models of lake invasibility by Bythotrephes longimanus, a non-indigenous zooplankton. Biol Invasions 2011. [DOI: 10.1007/s10530-011-0075-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Zhang W, Chang JF, Wan BN, Xu GS, Xiao CJ, Li B, Xu CS, Yan N, Wang L, Liu SC, Jiang M, Liu P. Fast reciprocating probe system on the EAST superconducting tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2010; 81:113501. [PMID: 21133465 DOI: 10.1063/1.3499237] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A new fast reciprocating probe system (FRPS) has been built and installed on the outer midplane of the EAST tokamak to investigate the profiles of the boundary plasma parameters such as electron density and temperature. The system consists of a two-stage motion drive mechanism: slow motion and fast motion. The fast motion is powered by a servo motor, which drives the probe horizontally up to 50 cm to scan the edge region of the EAST tokamak. The maximum velocity achieved is 2 m/s. High velocity and flexible control of the fast motion are the remarkable features of this FRPS. A specially designed connector installed at the front end of the probe shaft makes it easy to install or replace the probe head on FRPS. During the latest experimental campaign in the spring of 2010, a probe head with seven tips, including two tips for a Mach probe, has been used. An example is given for simultaneous profile measurements of the plasma temperature, plasma density, and the plasma flow velocity.
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Azadi P, Farnood R, Yan N. Modeling the effect of pigment morphology on the dynamic compression of coating layers using DEM. Comput Chem Eng 2008. [DOI: 10.1016/j.compchemeng.2008.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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41
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Thomas J, Wang W, Yan N, Su C, Lynn R, Stambler N, Israel R. Analysis of response to methylnaltrexone by response to previous dose in advanced illness patients with opioid-induced constipation. J Clin Oncol 2008. [DOI: 10.1200/jco.2008.26.15_suppl.9626] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Dean BB, Aguilar D, Johnson LF, McGuigan JE, Orr WC, Fass R, Yan N, Morgenstern D, Dubois RW. Night-time and daytime atypical manifestations of gastro-oesophageal reflux disease: frequency, severity and impact on health-related quality of life. Aliment Pharmacol Ther 2008; 27:327-37. [PMID: 18005248 DOI: 10.1111/j.1365-2036.2007.03574.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Respondents with gastro-oesophageal reflux disease (GERD) report having a variety of atypical manifestations. The relationship between these manifestations and disease severity, night-time GERD and functioning has not been determined. AIM To determine if atypical manifestations are related to increased disease severity, night-time GERD and decreased functioning. METHODS A web survey among US adults was conducted, using a validated GERD screener. Frequency of night-time and daytime typical symptoms (acid regurgitation and heartburn) and atypical manifestations were assessed. Respondents were classified as night-time GERD or daytime GERD based on typical symptom frequency. Prevalence of frequent atypical manifestations (> or =2 days or nights/week) was assessed. RESULTS Gastro-oesophageal reflux disease cases had a higher prevalence of each atypical manifestation (P < 0.05 for all) compared with controls. Night-time GERD respondents had a higher prevalence of atypical manifestations compared with daytime GERD respondents (P < 0.05 for most manifestations) and the prevalence of atypical manifestations increased with GERD symptom severity (P < 0.05 for most). Those with atypical manifestations reported lower functioning scores (P < 0.05 for most). CONCLUSIONS Respondents with typical GERD symptoms commonly report atypical manifestations, especially those with night-time symptoms and those with greater underlying GERD severity. Respondents with GERD and atypical manifestations had more impaired functioning than those with typical symptoms only.
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Feng L, Yan H, Wu Z, Yan N, Wang Z, Jeffrey PD, Shi Y. Structure of a Site-2 Protease Family Intramembrane Metalloprotease. Science 2007; 318:1608-12. [DOI: 10.1126/science.1150755] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Keller WB, Heneberry J, Leduc J, Gunn J, Yan N. Variations in epilimnion thickness in small boreal shield lakes: relationships with transparency, weather and acidification. ENVIRONMENTAL MONITORING AND ASSESSMENT 2006; 115:419-31. [PMID: 16614780 DOI: 10.1007/s10661-006-7237-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2005] [Accepted: 05/10/2005] [Indexed: 05/08/2023]
Abstract
We used multiple linear regression analysis to investigate relationships between late-summer epilimnion thickness, transparency, lake area, acidity and summer weather conditions in a large ($n = 116$) multi-year data set for 9 small Boreal Shield lakes. Dissolved organic carbon (DOC) was the best individual predictor of late summer epilimnion thickness ($r;{2} = 0.69$). Total chlorophyll~$a$, the number of days between ice-out and late-summer stratification, and lake area collectively explained an additional 14% of the variation in epilimnion thickness. The three attributes of summer weather that we examined, mean daily temperature, mean daily wind speed, and mean daily hours of bright sunshine, did not add to the predictive ability of our regression model. Lake acidity also did not add directly to the predictive ability of the model, likely because DOC concentrations already reflected the effects of pH. Our study supports an increasing body of evidence indicating that the dominant effects of climate change on lake thermal structure in small lakes will be through effects on processes that affect lake transparency.
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Yan N, Leip D, Gupta K. The use of open-source software in the IBM corporate portal. ACTA ACUST UNITED AC 2005. [DOI: 10.1147/sj.442.0419] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Arnott SE, Keller B, Dillon PJ, Yan N, Paterson M, Findlay D. Using temporal coherence to determine the response to climate change in Boreal Shield lakes. ENVIRONMENTAL MONITORING AND ASSESSMENT 2003; 88:365-388. [PMID: 14570423 DOI: 10.1023/a:1025537628078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Climate change is expected to have important impacts on aquatic ecosystems. On the Boreal Shield, mean annual air temperatures are expected to increase 2 to 4 degrees C over the next 50 years. An important challenge is to predict how changes in climate and climate variability will impact natural systems so that sustainable management policies can be implemented. To predict responses to complex ecosystem changes associated with climate change, we used long-term biotic databases to evaluate how important elements of the biota in Boreal Shield lakes have responded to past fluctuations in climate. Our long-term records span a two decade period where there have been unusually cold years and unusually warm years. We used coherence analyses to test for regionally operating controls on climate, water temperature, pH, and plankton richness and abundance in three regions across Ontario: the Experimental Lakes Area, Sudbury, and Dorset. Inter-annual variation in air temperature was similar among regions, but there was a weak relationship among regions for precipitation. While air temperature was closely related to lake surface temperatures in each of the regions, there were weak relationships between lake surface temperature and richness or abundance of the plankton. However, inter-annual changes in lake chemistry (i.e., pH) were correlated with some biotic variables. In some lakes in Sudbury and Dorset, pH was dependent on extreme events. For example, El Nino related droughts resulted in acidification pulses in some lakes that influenced phytoplankton and zooplankton richness. These results suggest that there can be strong heterogeneity in lake ecosystem responses within and across regions.
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Abstract
Whether or not neuron death plays a major role in pathophysiology during hydrocephalus is not well known. The goals of this study were to determine if neural degeneration occurred during hydrocephalus, and to determine if neuron tolerance developed during this pathophysiologic procedure.Neural damage as visualized by a sensitive staining technique, silver impregnation, was observed in three experimental groups: (1) adult hydrocephalic rats induced by kaolin injection into the cisterna magna, (2) adult rats with chronic hydrocephalus for 10 weeks subjected to acute forebrain ischemia induced by four-vessel occlusion, and (3) adult rats without hydrocephalus subjected to acute forebrain ischemia. The magnitude of hydrocephalus was also evaluated during this time. In mild or moderate hydrocephalus, little cell death was found. In severe hydrocephalus, axon and neuropil degeneration was extensively distributed, but cell death was still rarely observed. Although some neuron degeneration was found after acute forebrain ischemia in hydrocephalic rats, the extensive cell death in cortical layers III and V, and in hippocampal areas CA1 and CA4 that is commonly observed in the ischemic brain without hydrocephalus, was not seen. This study suggests that neuron death was not a major pathological change in the brain during hydrocephalus, with cerebral ventricles being enlarged during the development of hydrocephalus. Less neuron death in hydrocephalic rats after acute forebrain ischemia suggests that neuronal tolerance to ischemia occurs during hydrocephalus.
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Doelling JH, Yan N, Kurepa J, Walker J, Vierstra RD. The ubiquitin-specific protease UBP14 is essential for early embryo development in Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2001; 27:393-405. [PMID: 11576424 DOI: 10.1046/j.1365-313x.2001.01106.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The ubiquitin/26S proteasome pathway is a major route for selectively degrading cytoplasmic and nuclear proteins in eukaryotes. In this pathway, chains of ubiquitins become attached to short-lived proteins, signalling recognition and breakdown of the modified protein by the 26S proteasome. During or following target degradation, the attached multi-ubiquitin chains are released and subsequently disassembled by ubiquitin-specific proteases (UBPs) to regenerate free ubiquitin monomers for re-use. Here, we describe Arabidopsis thaliana UBP14 that may participate in this recycling process. Its amino acid sequence is most similar to yeast UBP14 and its orthologues, human IsoT1-3 and Dictyostelium UbpA, and it can functionally replace yeast UBP14 in a ubp14Delta mutant. Like its orthologues, AtUBP14 can disassemble multi-ubiquitin chains linked internally via epsilon-amino isopeptide bonds using Lys48 and can process some, but not all, translational fusions of ubiquitin linked via alpha-amino peptide bonds. However, unlike its yeast and Dictyostelium orthologues, AtUBP14 is essential in Arabidopsis. T-DNA insertion mutations in the single gene that encodes AtUBP14 cause an embryonic lethal phenotype, with the homozygous embryos arresting at the globular stage. The arrested seeds have substantially increased levels of multi-ubiquitin chains, indicative of a defect in ubiquitin recycling. Taken together, the data demonstrate an essential role for the ubiquitin/26S proteasome pathway in general and for AtUBP14 in particular during early plant development.
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Ding Y, McAllister JP, Yao B, Yan N, Canady AI. Axonal damage associated with enlargement of ventricles during hydrocephalus: a silver impregnation study. Neurol Res 2001; 23:581-7. [PMID: 11547925 DOI: 10.1179/016164101101199045] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Motor and cognitive deficits are commonly associated with hydrocephalus. Although the mechanisms responsible for these impairments have not been confirmed, neuronal cell death and axon degeneration may play an important role, and have long lasting consequences on neuronal connectivity. The goal of this study was to determine if neural degeneration occurred during hydrocephalus in structures anatomically related to cognitive motor functioning, namely, the sensorimotor cortex, neostriatum, hippocampus and corpus callosum. Neural damage, as visualized by silver staining, was examined in adult rats 2-10 weeks after obstructive hydrocephalus was induced by kaolin injection into the cisterna magna. In mild or moderate hydrocephalus, mostly occurring 2-6 weeks after kaolin injections, silver-labeled axons were scattered in the white matter of the sensorimotor cortex, corpus callosum, neostriatum, and hippocampus. In severe hydrocephalus, 10 weeks after kaolin injections, axon degeneration was more extensive in these areas, as well as in layers IV through VI of the sensorimotor cortex. Axons in the subiculum and the fimbria were heavily labeled, suggesting damage to hippocampal afferent and efferent fibers. In contrast, neuron cell death was rarely observed at any stage of hydrocephalus. The major pathological change of brain regions involved in motor and learning functions during hydrocephalus is axon degeneration, and this degeneration is correlated with an enlargement of the cerebral ventricles.
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Yan N, Yang H, Wu Z, Tan T, Li D. [Degradation of trichloroethylene by discharge plasma process]. HUAN JING KE XUE= HUANJING KEXUE 2001; 22:11-4. [PMID: 11507894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Two types of discharge and two kinds of discharge reactors was employed to decompose trichloroethylene (TCE) in air. The results showed that both pulsed discharge and AC discharge were efficient to the degradation of TCE. Under the pulsed discharge with peak voltage of 42 kV, gas resident time of 15 s and TCE initial concentration of 1350 mg/m3, the degradation efficiency of TCE was close to 100% in the hallow reactor and the higher voltage results in a higher degradation efficiency. For the AC discharge, the degradation efficiency of TCE reached 90% with applied voltage of 30 kV. Meanwhile, increasing the applied frequency of AC voltage can enhance the degradation of TCE. The energy consumption for TCE degradation by AC discharge was higher than that by pulsed discharge. The energy consumption for TCE degradation efficiency of 80% by pulsed and AC discharge were 4.9 W.h/m3 and 116 W.h/m3, respectively. In addition, the energy consumption in the packed reactor was higher comparing with that in the hallow one.
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