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81.
Weixia Zhong Omar Shahbaz Garrett Teskey Abrianna Beever Nala Kachour Vishwanath Venketaraman Nissar A. Darmani 《International journal of molecular sciences》2021,22(11)
Nausea and vomiting are common gastrointestinal complaints that can be triggered by diverse emetic stimuli through central and/or peripheral nervous systems. Both nausea and vomiting are considered as defense mechanisms when threatening toxins/drugs/bacteria/viruses/fungi enter the body either via the enteral (e.g., the gastrointestinal tract) or parenteral routes, including the blood, skin, and respiratory systems. While vomiting is the act of forceful removal of gastrointestinal contents, nausea is believed to be a subjective sensation that is more difficult to study in nonhuman species. In this review, the authors discuss the anatomical structures, neurotransmitters/mediators, and corresponding receptors, as well as intracellular emetic signaling pathways involved in the processes of nausea and vomiting in diverse animal models as well as humans. While blockade of emetic receptors in the prevention of vomiting is fairly well understood, the potential of new classes of antiemetics altering postreceptor signal transduction mechanisms is currently evolving, which is also reviewed. Finally, future directions within the field will be discussed in terms of important questions that remain to be resolved and advances in technology that may help provide potential answers. 相似文献
82.
Omar Hatamleh Iris V. Rivero Jed Lyons 《Journal of Materials Engineering and Performance》2007,16(5):549-553
The effects of laser, and shot peening on the residual stresses in friction stir welds (FSW) has been investigated. The surface
residual stresses were measured at five different locations across the weld in order to produce an adequate residual stress
profile. The residual stresses before and after sectioning the coupon from the welded plate were also measured, and the effect
of coupon size on the residual stress relaxation was determined and characterized. Measurements indicate that residual stresses
were not uniform along the welded plate, and large variation in stress magnitude could be exhibited at various locations along
the FSW plate. Sectioning resulted in significant residual stress relaxation in the longitudinal direction attributed to the
large change in dimensions in this direction. Overall, laser and shot peening resulted in a significant reduction in tensile
residual stresses at the surface of the specimens. 相似文献
83.
O.E.E.K. Omar T. El-Wardany E. Ng M.A. Elbestawi 《International Journal of Machine Tools and Manufacture》2007,47(7-8):1263-1275
During the milling operation, the cutting forces will induce vibration on the cutting tool, the workpiece, and the fixtures, which will affect the surface integrity of the final part and consequently the product's quality. In this paper, a generic and improved model is introduced to simultaneously predict the conventional cutting forces along with 3D surface topography during side milling operation. The model incorporates the effects of tool runout, tool deflection, system dynamics, flank face wear, and the tool tilting on the surface roughness. An improved technique to calculate the instantaneous chip thickness is also presented. The model predictions on cutting forces and surface roughness and topography agreed well with experimental results. 相似文献
84.
Muhammad Nor Omar Humphrey A. Moynihan Richard J. Hamilton 《European Journal of Lipid Science and Technology》2003,105(1):43-44
The asymmetric Sharpless epoxidation of methyl 13S‐hydroxy‐9Z, 11E‐octadeca‐dienoate (13S‐HODE, 1 ) with tert‐butyl hydroperoxide (TBHP) catalysed by titanium tetraisopropoxide {Ti(iOPr)4} in the presence of L(+)‐diisopropyl tartrate (L‐DIPT) gave methyl 13S‐hydroxy‐11S, 12S‐epoxy‐9Z‐octadecenoate 2 (erythro isomer) in 84% diastereomeric excess (de). The epoxidation of 1 with TBHP catalysed by Ti(iOPr)4 in the presence of D(‐)‐DIPT yielded methyl 13S‐hydroxy‐11RR12R‐epoxy‐9Z‐octadecenoate (threo isomer) 3 in 76% de. 相似文献
85.
Discriminative models are used to analyze the differences between two classes and to identify class-specific patterns. Most of the existing discriminative models depend on using the entire feature space to compute the discriminative patterns for each class. Co-clustering has been proposed to capture the patterns that are correlated in a subset of features, but it cannot handle discriminative patterns in labeled datasets. In certain biological applications such as gene expression analysis, it is critical to consider the discriminative patterns that are correlated only in a subset of the feature space. The objective of this paper is twofold: first, it presents an algorithm to efficiently find arbitrarily positioned co-clusters from complex data. Second, it extends this co-clustering algorithm to discover discriminative co-clusters by incorporating the class information into the co-cluster search process. In addition, we also characterize the discriminative co-clusters and propose three novel measures that can be used to evaluate the performance of any discriminative subspace pattern-mining algorithm. We evaluated the proposed algorithms on several synthetic and real gene expression datasets, and our experimental results showed that the proposed algorithms outperformed several existing algorithms available in the literature. 相似文献
86.
The interface behaviour in the facilitated co-transport of Ag(I), Cu(II) and Zn(II) ions through supported liquid membranes (SLMs) made of a flat-sheet polypropylene membrane support containing cryptands (2.2.2 or 2.2.1) as carriers was studied. The liquid-liquid extraction tests showed a maximum distribution coefficient when the carrier concentration was greaterthan 10−4M. In transport experiments the transmembrane flux increased with increasing carrier concentration reaching a limiting value at greater than 10−3M concentration. The calculation ofthe diffusion coefficients in membranes showed ahigherdiffusivityof2.2.2-metal complexes with respect to 2.2.1-metal complexes for silver ions. A sequence of diffusivity D(Ag+)>D(Cu2+)>D(Zn2+) was obtained, but carrier 2.2.1 showed a higher selectivity through copper ions. A sequence of diffusivity D(Cu2+)>D(Zn2+)>D(Ag+) was obtained. The diffusivity was significantly higher when using Celgard 2500 support compared to Celgard 2400 or 2402. Variable metal ion concentrations in the feed phase fluxes almost zero, at less than 10−2 M concentration, were obtained. In the transient state of the transport through the SLM, different molar flow rates at the feed-membrane and membrane-strip interfaces were observed. The selectivity of the interfaces containing 2.2.2 in the separation binary mixtures of ions showed the following separation factors: SFAgZn = 2.50, SFAgCu = 1.64, SFcuZn = 1.42. 相似文献
87.
Anibal Mario Nervi Raul Omar Peluffo Rodolfo R. Brenner Alicia Isabel Leikin 《Lipids》1980,15(4):263-268
The effect of ethanol on the fatty acid desaturation by rat liver has been studied using liquid diets of different composition.
Acute ethanol administration increased triacylglycerols of total liver lipids, but did not modify significantly the lipidic
composition of microsomes. The Δ6 and Δ5 desaturases were inhibited by ethanol whereas the Δ9 desaturase and fatty acid synthetase
were apparently modified only by diet composition. NADH-cytochrome (cyt.) c reductase was partially inhibited, whereas NADH-cyt.
b5 reductase remained practically unaltered and NADPH-cyt. c reductase activity was enhanced. Decreased electrons supplied by
the microsomal cyt. b5 electron transport chain would not be the reason for the inhibition of Δ6 and Δ5 desaturases by ethanol. 相似文献
88.
Shen TJ; Ho NT; Zou M; Sun DP; Cottam PF; Simplaceanu V; Tam MF; Bell DA Jr; Ho C 《Protein engineering, design & selection : PEDS》1997,10(9):1085-1097
A hemoglobin expression system in Escherichia coli is described. In order
to produce authentic human hemoglobin, we need to co-express both
methionine aminopeptidase and globin genes under the control of a strong
promoter. We have constructed three plasmids, pHE2, pHE4 and pHE7, for the
expression of human normal adult hemoglobin and a plasmid, pHE9, for the
expression of human fetal hemoglobin, in high yields. The globin genes can
be derived from either synthetic genes or human globin cDNAs. The extra
amino-terminal methionine residues of the expressed globins can be removed
by the co-expressed methionine aminopeptidase. The heme is inserted
correctly into the expressed alpha- globin from our expression plasmids. A
fraction (approximately 25%) of the heme is not inserted correctly into the
expressed beta- or gamma- globin. However, the incorrectly inserted hemes
can be converted into the correct conformation by carrying out a simple
oxidation-reduction process on the purified hemoglobin molecule. We have
investigated the functional properties of the expressed hemoglobins by
measuring their oxygen-binding properties and their structural features by
obtaining their 1H-NMR spectra. Our results show that authentic human
normal adult and fetal hemoglobins can be produced from our expression
plasmids in E. coli and in high yields. Our expression system allows us to
design and to produce any recombinant hemoglobins needed for our research
on the structure-function relationship in hemoglobin.
相似文献
89.
Quintanar-Reséndiz Ana L. Rodríguez-Santos Francisco Pichardo-Méndez Josué L. Delgado-Gutiérrez Guillermo Ramírez Omar Jiménez Vázquez-Medina Rubén 《Multimedia Tools and Applications》2021,80(13):19513-19538
Multimedia Tools and Applications - It is proposed a forensic method for the capture device identification from digital images, which requires two elements: i) a digital image subject to... 相似文献
90.
Maria del Rosario Martínez-Macias Rocio Janeth Aguilar-Ruiz Omar Nateras-Ramírez Dalia Isabel Sánchez-Machado Jaime López-Cervantes Germán Eduardo Dévora-Isiordia Jesús Álvarez-Sánchez Nidia Josefina Ríos-Vázquez 《Journal of the American Oil Chemists' Society》2021,98(10):993-1000
Greenhouse gases emitted into the atmosphere by burning of fossil fuels cause global warming. One option is obtaining biodiesel. Nannochloropsis oculata was cultured under different light intensities and reactors at 25°C for 21 days with f/2 medium to assess their effects on cell density, lipid, and fatty acids (FAs). N. oculata improved cell density on fed-batch glass tubular reactor (7 L) at 200 μmol E m−2 s−1, yielding 3.5 × 108 cells ml−1, followed by fed-batch Erlenmeyer flask (1 L) at 650 μmol E m−2 s−1 with 1.7 × 108 cells ml−1. The highest total lipid contents (% g lipid × g dry biomass−1) were 44.4 ± 0.8% for the reactor (1 L) at 650 μmol E m−2 s−1 and 35.2 ± 0.2% for the tubular reactor (7 L) at 200 μmol E m−2 s−1, until twice as high compared with the control culture (Erlenmeyer flask 1 L, 80 μmol E m−2 s−1) with 21.2 ± 1%. Comparing the total lipid content at 200 μmol E m−2 s−1, tubular reactor (7 L) and reactor 1 L achieved 35.2 ± 0.2% and 28.3 ± 1%, respectively, indicating the effect of shape reactor. The FAs were affected by high light intensity, decreasing SFAs to 2.5%, and increased monounsaturated fatty acids + polyunsaturated fatty acids to 2.5%. PUFAs (20:5n-3) and (20:4n-3) were affected by reactor shape, decreasing by half in the tubular reactor. In the best culture, fed-batch tubular reactor (7 L) at 200 μmol E m−2 s−1 contains major FAs (16:0; 38.06 ± 0.16%), (16:1n-7; 30.74 ± 0.58%), and (18:1n-9; 17.15 ± 0.91%). 相似文献