How do heavy metal ATPases contribute to hyperaccumulation?          下载免费PDF全文

Won Park  Sung‐Ju Ahn 《植物养料与土壤学杂志》2014,177(2):121-127

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Wnt5a control of cell polarity and directional movement by polarized redistribution of adhesion receptors     

Witze ES  Litman ES  Argast GM  Moon RT  Ahn NG 《Science (New York, N.Y.)》2008,320(5874):365-369

Mechanisms by which Wnt pathways integrate the organization of receptors, organelles, and cytoskeletal proteins to confer cell polarity and directional cell movement are incompletely understood. We show that acute responses to Wnt5a involve recruitment of actin, myosin IIB, Frizzled 3, and melanoma cell adhesion molecule into an intracellular structure in a melanoma cell line. In the presence of a chemokine gradient, this Wnt-mediated receptor-actin-myosin polarity (W-RAMP) structure accumulates asymmetrically at the cell periphery, where it triggers membrane contractility and nuclear movement in the direction of membrane retraction. The process requires endosome trafficking, is associated with multivesicular bodies, and is regulated by Wnt5a through the small guanosine triphosphatases Rab4 and RhoB. Thus, cell-autonomous mechanisms allow Wnt5a to control cell orientation, polarity, and directional movement in response to positional cues from chemokine gradients.  相似文献   

信阳地区杂交水稻高产高效益栽培模式的研究与应用     

河南信阳农专“双高”开发课题组 《杂交水稻》1993,(1):27-29

河南信阳地区提出了该地区杂交水稻大面积亩产６００公斤以上的最佳栽培模式为：适栽组合应以汕优６３为主;苗栽１．８～２万穴,两段育秧,亩施纯氮１０～１８公斤;钙镁磷肥５０公斤,多效唑１６０克左右;普及一喷三防技术．１９９２年在固始县,罗山县、满川县共推广７．１３万亩,增产１２６３．３６万公斤,增收８８４．３５万元．  相似文献   

GC-MS analysis of curcumin dye after selective degradation treatment     

Cheunsoon Ahn  S. Kay Obendorf 《Fibers and Polymers》2007,8(3):278-283

Curcumin dye in methanol solution was treated in 100°C oven (OV) and H₂O₂/UV/O₂ (PER) conditions and the degradation products were examined using gas chromatography mass spectrometry (GC-MS). Curcumin itself was not detected from either the OV or PER degraded samples. From OV degradation samples curcumene1, o-coumaric acid2, vanillin3, 2,4-di-tert-butylphenol4, benzene, 1-(3-cyclopentylpropyl)-2,4-dimethyl-45, 1-(4-hydroxy-benzylidene) acetone6, feruloylmethane7, and 2-propenoic acid, 3-[4-(acetyloxy)-3-methoxy phenyl]-, methyl ester8 were detected. From PER degraded samples new products benzoic acid9 and vanillic acid10 were detected additionally. Under the same GC-MS instrumental condition, it is possible that the burial degraded curcumin dye or curcumin dyed textile will exhibit area peaks around 6.2∼6.5 min and 8.3∼8.4 min retention times, which have the mass spectrum matching closely with products3, 4, 7, 8 or9, 10.  相似文献   

Effect of enzyme treatment and wood pulp variation on physical characteristics and fabric hand of lyocell fabrics     

Cheunsoon Ahn  Hye-Ja Yoo  Hye Ja Lee  Jung Hee Kim  Kyung-Hun Song  Jeon Sook Rhie 《Fibers and Polymers》2005,6(1):28-34

The purpose of the research was to examine the effect of three different levels of enzyme treatment on the physical characteristics and the end-use suitability of the lyocell fabrics made with four different types of commercial wood pulp. The appropriate enzyme concentration for obtaining an optimum as well as consistent physical characteristics and fabric hand trait was 3 g/l for the concentration levels tested in the present investigation. Weight loss was more affected by higher enzyme concentration than other physical properties. H2 was least affected by enzyme treatment for all three physical properties and fabric hand. 5 g/l concentration exhibited little difference from 3 g/l in the physical characteristics, whereas the KES-FB values indicated a significant loss of fabric hand in most PHVs with the 5 g/l concentration level. Among different garment parameters, all four fabric types were relatively inappropriate for the men’s slacks (MS) fabric due to the lower hand value of koshi required by the MS parameter. However, despite the relatively low koshi values, high fukurami values required for men’s dress shirt (MWDS) resulted in the highest THV among the four garment parmeters. The four fabric types, which represent the usage of four different wood pulps, in general seem to exhibit a higher applicability to women’s winter thin dress (WWTD) than women’s winter suit (WWS) garment parameter.  相似文献   

Measurement of cardiac output by transesophageal Doppler ultrasonography in anesthetized dogs: comparison with thermodilution     

T Lazic  DH Riedesel  RB Evans 《Veterinary anaesthesia and analgesia》2003,30(2):104-105

Thermodilution (TD) is the standard method for cardiac output (CO) monitoring in human medicine. Although called the ‘gold standard’, TD is related to numerous complications and data misinterpretations. Recently, a noninvasive, continuous, ultrasound‐based technique for CO measurement has been developed (Hemosonic 100, Arrow Intl). This study compared transesophageal Doppler ultrasonography (TED) for measuring CO with TD in anesthetized dogs. In this study, ten dogs were used to simultaneously measure CO by TED and TD. All dogs were pre‐medicated with acepromazine at 0.1 mg kg^?1 IM, induced with thiopental at 10 mg kg^?1 IV, and maintained on isoflurane at end‐tidal concentrations of 1.3%. Baseline and four different levels of CO were used for comparison. Low CO levels were induced by caudal vena cava occlusion. High CO levels were induced by the constant IV infusion of dopamine, dobutamine, or norepinephrine. Each level of CO allowed one comparison between TED and TD. Forty‐nine paired comparisons of CO were determined ranging from 0.73 to 10.9 L minute^?1. Simple linear regression was used to determine the correlation between the two techniques. Correlation coefficient (r²) was 0.53. Bland and Altman statistical method was used for assessing agreement between the two methods. The difference between the TD and TED when all data were included was 0.82 (bias) ± 1.63 L minute^?1 (mean ± SD). At low CO levels (baseline and caudal vena cava occlusion), the correlation coefficient was 0.77, bias was 0.35 ± 0.64 L minute^?1. At high CO levels (dopamine, dobutamine, or norepinephrine), the correlation coefficient was 0.39. It was concluded that TED was not a reliable monitoring method in determining CO when positive inotropes were used. TED might have importance in situations of low CO values; however, further investigation is warranted.  相似文献   

A comparison of anesthetic risk factors and outcomes in light and draft horses     

CB  Riley †  DH Riedesel  ‡  IR Dohoo†  CL Hatfield†  S Clinch† 《Veterinary anaesthesia and analgesia》2003,30(2):113-114

As a result of anatomic and physiologic differences, draft breeds may be at greater risk of developing anesthetic complications. The aim of the study was to evaluate and compare anesthetic management of draft (DR) and light (LT) horses. A case‐matched retrospective study of 371 clinical case records of DR (124 cases) and LT (247 cases) horses presented for general anesthesia between 1991 and 1998 was performed. Data were tabulated and comparisons were made using Student's t‐test (significance p < 0.05). Prior to induction, there were significant differences in mean body weight, rectal temperature, PCV, RBC, and serum TP concentration between DR and LT breeds. There were differences in mean doses of pre‐operative butorphanol (LT 21 µg kg^?1; DR 17 µg kg^?1), induction guaifenesin (LT 99 mg kg^?1; DR 88 mg kg^?1), and intraoperative ketamine (LT 0.35 mg kg^?1; DR 0.56 mg kg^?1) required. There were no significant differences in the mean doses of pre‐operative xylazine, detomidine, or induction barbiturate administered. The mean, average, and maximum concentrations of inspired halothane were significantly higher for DR than for LT horses. Draft horses received 33% less intraoperative IV fluids (8.2 mL kg^?1 hour^?1) than LT horses. Mean anesthetic duration, time to extubation, and standing recovery were not significantly different. Induction complications were not reported for either group. Rates of occurrence of intraoperative bradycardia, hypercarbia, hypoxemia, and metabolic acidosis (SBE, TCO₂, and bicarbonate concentration) did not differ significantly. Average MAP was greater in DR horses, but neither the degree nor the mean duration of hypotension differed between DR and LT horses. Mean PaO₂ was significantly lower in DR (246 mm Hg, 32.8 kPa) than in LT (305 mm Hg, 40.7 kPa) breeds. Draft horses were at greater relative risk of hypoventilation than LT horses. The greater MAP and requirement for halothane and intraoperative ketamine may indicate problems in achieving and maintaining a surgical plane of anesthesia. Draft horses may be at a greater risk of ventilation–perfusion mismatching.  相似文献   

Prediction and interpretation of hydraulic permeability for nonwoven fabrics considering hypothetical 2-D layer     

Seung Jae Ahn  Moo Sung Lee  Dae Young Lim  Jung Nam Im  Seung Goo Lee  Ji Ho Youk  Han-Yong Jeon 《Fibers and Polymers》2013,14(12):2191-2196

The permeability defined by Darcy’s law indicates the degree of ability that a fluid can flow through nonwoven media under a differential pressure in laminar flow. The permeability generally indicates the specific permeability or absolute permeability. On the other hand, if the fluid is water, the permeability indicates the hydraulic conductivity or permeability coefficient. The permeability is one of the important properties for nonwoven media and a prediction of the permeability acts as a bridge between the manufacturing technology and performance requirements. Because capillary channel theory aims to make the flow of fluid easier and more understandable, many models are based on capillary channel theory. On the other hand, the theory has a limitation in that it is unsuitable for high porosity media. In this study, a very thin downstream layer, which was suggested by Lifshutz [9], was introduced to derive a prediction model of hydraulic permeability. Needle-punched and spunbonded nonwoven fabrics with various basis weights were used in the cross-plain water permeability test. From this ‘thin layer’ model, reasonable agreement between the predicted and experimental results was obtained.  相似文献   

Contact and fumigant toxicity of Pinus densiflora needle hydrodistillate constituents and related compounds and efficacy of spray formulations containing the oil to Dermatophagoides farinae     

Ju‐Hee Lee  Jun‐Ran Kim  Young Ryull Koh  Young‐Joon Ahn 《Pest management science》2013,69(6):696-702

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Solvent-free acid-catalyzed ring-opening of epoxidized oleochemicals using stearates/stearic acid, and its applications     

Ahn BJ  Kraft S  Sun XS 《Journal of agricultural and food chemistry》2012,60(9):2179-2189

Toxic solvent and strong acid catalysts causing environmental issues have been mainly used for ring-opening of epoxidized oleochemicals. Here, we demonstrated that magnesium stearate (Mg-stearate) was a high efficient catalyst for solvent-free ring-opening of epoxidized methyl oleate, a model compound of midchain epoxide. Mg-stearate resulted in the highest yield (95%) and conversion rate (99%) toward midchain alkoxyesters under the same conditions (160 °C, 12 h) superior to other fatty acid derivatives such as a Lewis acid (lithium and sodium stearate) and Br?nsted acid (stearic acid). Based on this chemical study, we synthesized biogrease and thermoplastic using epoxidized soybean oil (ESO) and Mg-stearate via one-pot, solvent-free, and purification-free process. Mg-stearate played a significant role as a reactant for epoxide ring-opening and as a thickener when excess loading rate was used; viscosity increased from 1800 to 4500 Pa·s at 25 °C when ESO:Mg-stearate increased from 1:1 equiv to 1:2, then behaved like thermoplastics (T(g) = -27 °C, T(m) = 90 °C) with 1:4.  相似文献