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1.
K Tordjman N Stern G Ouaknine Y Yossiphov N Razon M Nordenskj?ld E Friedman 《Canadian Metallurgical Quarterly》1993,77(3):765-769
The majority of pituitary tumors are of monoclonal origin; however, the molecular basis for their formation is poorly understood. Somatic mutations in the alpha-subunit of the GTP-binding protein, Gs alpha (gsp oncogene) have been found in about one third of GH-secreting tumors. Mutations in another alpha-subunit of a GTP-binding protein, Gi2 alpha (gip mutations) have been described in other endocrine tumors. In this study, we examined 21 nonfunctioning pituitary tumors and 4 macroprolactinomas for gsp mutations and 27 nonfunctioning tumors and 4 macroprolactinomas for gip mutations. Using the polymerase chain reaction and denaturing gradient gel electrophoresis, 2 nonfunctioning pituitary tumors displayed migration abnormalities when the Gs alpha-gene was analyzed. Sequence analysis of these abnormally migrating polymerase chain reaction products revealed two previously known gsp mutations: arginine at codon 201 altered to cysteine, and glutamine at codon 227 changed to leucine. No gip mutations could be demonstrated. These findings emphasize the monoclonal origin of nonfunctioning pituitary tumors and suggest that cAMP may play a role in tumorigenesis of nonfunctioning pituitary tumors. 相似文献
2.
Hakime Hulya Orak Hulya Yagar Sebnem Selen Isbilir 《Food science and biotechnology》2012,21(2):373-387
In this study, the antioxidant activities of juice, peel, and seed parts of pomegranate were investigated by using DPPH scavenging
activity, β-carotene bleaching method, reducing power, and metal chelating activity. Sample of pomegranates which are named
Punica granatum L. cv. Hicaznar, genotype 19–121, genotype 17–67, and genotype 19–66 obtained from BATEM (West Mediterranean Agricultural Research Institute) in Anlalya. The EC50 values of DPPH scavenging activities in peel extracts (PE) had 23.4-fold higher than the juice extracts (JE), and the seed
extracts (SE) had 2.3-fold higher than JE. The reducing power in peel extracts was found to be 4.7-fold higher than SE and
10.5-fold higher than the JE. The highest metal chelating capacity (37.22%) was determined in peel, while the lowest (7.151%)
in seed. Generally, in peel, the total polyphenol, flavonoid, tannin contents, and in juice, the total polyphenol, anthocyanin,
tannin contents, and acidity significantly affected to antioxidant activities. 相似文献
3.
Solids transport models comparison and fine‐tuning for horizontal,low concentration flow in single‐phase carrier fluid 下载免费PDF全文
Frits Byron Soepyan Selen Cremaschi Cem Sarica Hariprasad J. Subramani Gene E. Kouba 《American Institute of Chemical Engineers》2014,60(1):76-122
We determined and fine‐tuned the solids transport models appropriate for predicting the single‐phase carrier fluid velocity to transport solid particles in conduits for horizontal, low concentration flow. A database with 538 experimental data points was compiled. A literature review was performed to determine the data ranges, forces, and mechanisms used to develop 44 models, and their velocity predictions were compared against the database using statistics. Using the dimensionless forms of the models and the data, the model parameters were adjusted to improve their accuracy and identify the dominant forces. At low concentrations: for liquid/solid flow from a bed of solids and gas/solid flow from the bottom of pipelines, the particle weight, and inertial and viscous forces dominate; for gas/solid flow from a bed of solids, the particle weight, and inertial, viscous, and adhesive forces play a role; and gaps exist in the data for large‐diameter pipes and high‐density gases. © 2013 American Institute of Chemical Engineers AIChE J, 60: 76–122, 2014 相似文献
4.
Artificial lift methods (ALMs) lift the accumulated fluids from horizontal shale-gas-producing wells and help sustain well performance. An artificial lift infrastructure plan includes the selection of ALMs and their operating schedule. This paper presents two discrete-time large-scale nonconvex mixed-integer nonlinear programming models to solve the artificial lift infrastructure planning problem. Two equivalent mixed-integer linear programming models are formulated using the special structure of the nonlinear terms. A set of valid inequalities is defined to tighten the models and shorten solution times to two orders of magnitude, considering well production limitations. We incorporate endogenous uncertainty in ALM-dependent production rates and exogenous uncertainty in shale gas prices into the models. For a hypothetical case study under only endogenous uncertainties, the value of the stochastic solution is 5%. For the same case study, the exogenous uncertainty in gas prices does not change the optimum solution. 相似文献
5.
Kellie Vella Madison Klarkowski Selen Turkay Daniel Johnson 《Behaviour & Information Technology》2020,39(8):917-934
ABSTRACT While online multiplayer games provide an opportunity for players to both maintain and establish new connections, male and female players have been found to experience these environments differently. Interviews (n?=?22) and focus groups (n?=?14) were used to explore these differences as they impact on creating new social connections, as well as to provide recommendations for the development of new social tools and features that account for these differences. While all participants experienced toxicity and performance pressure as barriers to forming new connections, female players uniquely reported the impacts of misogynistic targeting and stereotype threat. In turn, female players wishing to avoid these stresses would often mask their gender. The common practice of gender misrepresentation by both male and female players impacted female players’ ability to create social connections through voice technology, as well as building their distrust of unknown others. Recommendations are made to build social connectedness between players taking into account the specific constraints faced by female players. These include establishing mentoring opportunities as well as profiling players beyond their immediate skill or rank. Additionally, the desire for control of one’s online identity presents practical challenges that may be overcome through thoughtful design. 相似文献
6.
Gulsah Congur Elif Selen Ates Aysegul Afal Husnu Emrah Unalan Arzum Erdem 《Journal of the American Ceramic Society》2015,98(2):663-668
The surfaces of pencil graphite electrodes (PGEs) were decorated with zinc oxide nanowires (ZnO NWs) for the electrochemical detection of nucleic acids. ZnO NWs were synthesized through simple hydrothermal method. PGEs decorated with ZnO NWs (ZnO NW/PGEs) were electrochemically characterized through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) following morphological characterization through transmission (TEM) and scanning electron microscopy (SEM). Enhanced sensor response obtained using ZnO NW/PGEs contrary to the bare PGE (control) samples. Our preliminary results simply reveal the potential of combining ZnO NWs with disposable sensor technology for the electrochemical detection of DNA. 相似文献
7.
Multimedia Tools and Applications - Single image super resolution (SR) based on sparse representation is a promising technique where the SR problem is solved by searching for the most robust... 相似文献
8.
Data center demand response: Avoiding the coincident peak via workload shifting and local generation
Demand response is a crucial aspect of the future smart grid. It has the potential to provide significant peak demand reduction and to ease the incorporation of renewable energy into the grid. Data centers’ participation in demand response is becoming increasingly important given their high and increasing energy consumption and their flexibility in demand management compared to conventional industrial facilities. In this paper, we study two demand response schemes to reduce a data center’s peak loads and energy expenditure: workload shifting and the use of local power generation. We conduct a detailed characterization study of coincident peak data over two decades from Fort Collins Utilities, Colorado and then develop two algorithms for data centers by combining workload scheduling and local power generation to avoid the coincident peak and reduce the energy expenditure. The first algorithm optimizes the expected cost and the second one provides a good worst-case guarantee for any coincident peak pattern, workload demand and renewable generation prediction error distributions. We evaluate these algorithms via numerical simulations based on real world traces from production systems. The results show that using workload shifting in combination with local generation can provide significant cost savings (up to 40% under the Fort Collins Utilities charging scheme) compared to either alone. 相似文献
9.
Research activities and collaborations in nanoscale science and engineering have major implications for advancing technological
frontiers in many fields including medicine, electronics, energy, and communication. The National Nanotechnology Initiative
(NNI) promotes efforts to cultivate effective research and collaborations among nano scientists and engineers to accelerate
the advancement of nanotechnology and its commercialization. As of August 2008, there have been over 800 products considered
to benefit from nanotechnology directly or indirectly. However, today’s accomplishments in nanotechnology cannot be transformed
into commercial products without productive collaborations among experts from disparate research areas such as chemistry,
physics, math, biology, engineering, manufacturing, environmental sciences, and social sciences. To study the patterns of
collaboration, we build and analyze the collaboration network of scientists and engineers who conduct research in nanotechnology.
We study the structure of information flow through citation network of papers authored by nano area scientists. We believe
that the study of nano area co-author and paper citation networks improve our understanding of patterns and trends of the
current research efforts in this field. We construct these networks based on the publication data collected for years ranging
1993 through 2008 from the scientific literature database “Web of Science”. We explore those networks to find out whether
they follow power-law degree distributions and/or if they have a signature of hierarchy. We investigate the small-world characteristics
and the existence of possible community structures in those networks. We estimate the statistical properties of the networks
and interpret their significance with respect to the nano field. 相似文献
10.
In this paper, we present a robust hybrid watermarking method applied to color images for authentication, which presents robustness against several distortions. Due to the different nature of common signal processing and geometrical attacks, two different techniques for embed a same watermark are used in this method. In the first one, the luminance component (Y) information is used to embed the watermark bit sequence into the magnitude of the middle frequencies of the Discrete Fourier Transform (DFT). In the second one, a selected region of 2D histogram composed by blue-difference and red-difference (Cb–Cr) chrominance components is modified according to the watermark bit sequence. The quality of the watermarked image is measured using the following well-known indices peak signal to noise ratio (PSNR), visual information fidelity (VIF) and structural similarity index (SSIM). The difference color of the watermarked image is obtained using the normalized color difference (NCD) measure. The experimental results show that the proposed method provides robustness against several geometric distortions, signal processing operations, combined distortions and photo editing. The comparison with the previously reported methods based on different techniques is also provided. 相似文献