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1.
In this paper we give a short survey on a problem on extremal quasiconformal extensions. It had been a conjecture for a long time that the dilatations K0(h) and K1(h) are equal before Anderson and Hinkkanen disproved this by constructing concrete examples of a family of affine mappings of some parallelograms. The problem also engendered many interesting results. At the end of the current paper, we discuss relationships among K0(h), H(h) and K1(h) as a concluding remark.  相似文献   

2.
In plants, lipoxygenases (LOXs) play a crucial role in biotic and abiotic stresses. In our previous study, five 13-LOX genes of oriental melon were regulated by abiotic stress but it is unclear whether the 9-LOX is involved in biotic and abiotic stresses. The promoter analysis revealed that CmLOX09 (type of 9-LOX) has hormone elements, signal substances, and stress elements. We analyzed the expression of CmLOX09 and its downstream genes—CmHPL and CmAOS—in the leaves of four-leaf stage seedlings of the oriental melon cultivar “Yumeiren” under wound, hormone, and signal substances. CmLOX09, CmHPL, and CmAOS were all induced by wounding. CmLOX09 was induced by auxin (indole acetic acid, IAA) and gibberellins (GA3); however, CmHPL and CmAOS showed differential responses to IAA and GA3. CmLOX09, CmHPL, and CmAOS were all induced by hydrogen peroxide (H2O2) and methyl jasmonate (MeJA), while being inhibited by abscisic acid (ABA) and salicylic acid (SA). CmLOX09, CmHPL, and CmAOS were all induced by the powdery mildew pathogen Podosphaera xanthii. The content of 2-hexynol and 2-hexenal in leaves after MeJA treatment was significantly higher than that in the control. After infection with P. xanthii, the diseased leaves of the oriental melon were divided into four levels—levels 1, 2, 3, and 4. The content of jasmonic acid (JA) in the leaves of levels 1 and 3 was significantly higher than that in the level 0 leaves. In summary, the results suggested that CmLOX09 might play a positive role in the response to MeJA through the hydroperoxide lyase (HPL) pathway to produce C6 alcohols and aldehydes, and in the response to P. xanthii through the allene oxide synthase (AOS) pathway to form JA.  相似文献   

3.
Stress equilibrium equations, boundary-and continuity-conditions were used to establish a theoretical model of progressive debonding with friction at the debonded interface. On a basis of the minimum complementary energy principle, an expression for the energy release rateG was derived to explore the interfacial fracture properties. An interfacial debonding criterionGΓ i was introduced to determine the critical debond length and the bridging law. Numerical calculation results for fiber-reinforced composite SCS-6/Ti-6A1-4V were compared with those obtained by using the shear-lag models.  相似文献   

4.
Piled embankments are widely used in highway and railway engineering due to their economy and efficiency in overcoming several issues encountered in constructing embankments over weak soils. Soil arching, caused by the pile-subsoil relative displacement (Δs), plays an important role in reducing the embankment load falling on weak soil, however, the fundamental characteristics (e.g., formation and features) of soil arching remain poorly understood. In this study, a series of discrete element method (DEM) modellings are performed to study the formation and features of soil arching with the variation of Δs in piled embankments with or without geosynthetic reinforcement. Firstly, calibration for the modelling parameters is carried out by comparing the DEM results with the experimental data obtained from the existing literature. Secondly, the analysis of the macroand micro-behaviours is performed in detail. Finally, a parametric study is conducted in an effort to identify the influences of three key factors on soil arching: the friction coefficient of the embankment fill (f), the embankment height (h), and the pile clear spacing (s?a). Numerical results indicate that Δs is a key factor governing the formation and features of soil arching in embankments. To be specific, soil arching gradually evolves from two inclined shear planes at a small Δs to a hemispherical arch at a relatively large Δs. Then, with a continuous increase in Δs, the soil arching height gradually increases and finally approaches a constant value of 0.8(s?a) (i.e., the maximum soil arching height). For a given case, the higher the soil arching height, the greater the degree of soil arching effect. The parametric study shows that the friction coefficient of the embankment fill has a negligible influence on the formation and features of soil arching. However, embankment height is a key factor governing the formation and features of soil arching. In addition, pile clear spacing has a significant effect on the formation of soil arching, but not on its features.  相似文献   

5.
In this paper we will first prove that the nontrivial L p solutions of the vector refinement e-quation exist if and only if the corresponding subdivision scheme with a suitable initial function converges in L p without assumption of the stability of the solutions. Then we obtain a characterization of the convergence of the subdivision scheme in terms of the mask. This gives a complete answer to the existence of L p solutions of the refinement equation and the convergence of the corresponding subdivision schemes.  相似文献   

6.
1 Introduction AmatrixA∈Cn×missaidtobecentrohermitianifA =Jn AJm,andskewcentrohermitianifA =-Jn AJm,where Adenotetheconjugateofthema trixAandJlisthepermutationmatrixoforderlwithonesonthecrossdiagonal(bottomlefttotopright)andzeroselsewhere .ThehermitianToeplitzmatricesformanimportantsubclassofcentrohermi tianmatriceswhichoccurnaturallyindigitalsignalprocessingandotherareas ,seeforinstance[1] andreferencetherein .Thecentrohermitianandrelatedmatricesrecentlyplayanimportantroleinthesolu…  相似文献   

7.

Objective

Salmonella enterica remains a major cause of food-borne disease in humans, and Salmonella Typhimurium (ST) contamination of poultry products is a worldwide problem. Since macrophages play an essential role in controlling Salmonella infection, the aim of this study was to evaluate the effect of glycyrrhizic acid (GA) on immune function of chicken HD11 macrophages.

Methods

Chicken HD11 macrophages were treated with GA (0, 12.5, 25, 50, 100, 200, 400, or 800 μg/ml) and lipopolysaccharide (LPS, 500 ng/ml) for 3, 6, 12, 24, or 48 h. Evaluated responses included phagocytosis, bacteria-killing, gene expression of cell surface molecules (cluster of differentiation 40 (CD40), CD80, CD83, and CD197) and antimicrobial effectors (inducible nitric oxide synthase (iNOS), NADPH oxidase-1 (NOX-1), interferon-γ (IFN-γ), LPS-induced tumor necrosis factor (TNF)-α factor (LITAF), interleukin-6 (IL-6), and IL-10), and production of nitric oxide (NO) and hydrogen peroxide (H2O2).

Results

GA increased the internalization of both fluorescein isothiocyanate (FITC)-dextran and ST by HD11 cells and markedly decreased the intracellular survival of ST. We found that the messenger RNA (mRNA) expression of cell surface molecules (CD40, CD80, CD83, and CD197) and cytokines (IFN-γ, IL-6, and IL-10) of HD11 cells was up-regulated following GA exposure. The expression of iNOS and NOX-1 was induced by GA and thereby the productions of NO and H2O2 in HD11 cells were enhanced. Notably, it was verified that nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways were responsible for GA-induced synthesis of NO and IFN-γ gene expression.

Conclusions

Taken together, these results suggested that GA exhibits a potent immune regulatory effect to activate chicken macrophages and enhances Salmonella-killing capacity.
  相似文献   

8.

Objectives

To evaluate the possible photoprotection mechanisms of cyclic and linear electron flux (CEF and LEF) under specific high temperature and high light (HH) stress.

Methods

Six-leaf-stage tomato seedlings (“Liaoyuanduoli”, n=160) were divided into four parts: Part 1, served as control under 25 °C, 500 μmol/(m2·s); Part 2, spayed with distilled water (H2O) under 35 °C, 1000 μmol/(m2·s) (HH); Part 3, spayed with 100 μmol/L diuron (DCMU, CEF inhibitor) under HH; Part 4, spayed with 60 μmol/L methyl viologen (MV, LEF inhibitor) under HH. Energy conversion, photosystem I (PSI), and PSII activity, and trans-thylakoid membrane proton motive force were monitored during the treatment of 5 d and of the recovering 10 d.

Results

HH decreased photochemical reaction dissipation (P) and the maximal photochemical efficiency of PSII (F v/F m), and increased the excitation energy distribution coefficient of PSII (β); DCMU and MV aggravated the partition imbalance of the excitation energy (γ) and the photoinhibition degree. With prolonged DCMU treatment time, electron transport rate and quantum efficiency of PSI (ETRI and Y I) significantly decreased whereas acceptor and donor side limitation of PSI (Y NA and Y ND) increased. MV led to a significant decline and accession of yield of regulated and non-regulated energy Y NPQ and Y NO, respectively. Membrane integrity and ATPase activity were reduced by HH stress, and DCMU and MV enhanced inhibitory actions.

Conclusion

The protective effects of CEF and LEF were mediated to a certain degree by meliorations in energy absorption and distribution as well as by maintenance of thylakoid membrane integrity and ATPase activity.
  相似文献   

9.
Alloying is an effective way to manipulate the composition and physico-chemical properties of functional materials. We demonstrated the syntheses of alloyed Co x Ni1?x O nanocrystals using a nonaqueous approach, with x continuously tuned from 0 to 1 by varying the molar ratios of the cobalt precursor in the reagents. The morphological, structural, and compositional properties of the alloyed Co x Ni1?x O nanocrystals were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma atomic emission spectroscopy (ICP-AES), and energy dispersive X-ray spectroscopy (EDS). The results showed that the cobalt and nickel atoms were homogeneously distributed in the alloyed nanocrystals. The as-prepared Co x Ni1?x O nanocrystals can be applied as the hole-transporting layers in polymer light emitting diodes (PLEDs). Our study provides a good example for the syntheses of alloyed oxide nanocrystals with continuously tunable composition.  相似文献   

10.
As an easy application of the intermediate value theorem, one can show that for any continuous function f: [0, 1] → ? with f (0) = f (1), there are points a, a + 1/2 both in [0, 1] such that f (a) = f (a + 1/2). In this note, we show that this property holds with 1/2 replaced by any number of the form 1/n for a positive integer n. More interestingly, we show that this is false for every number not of the form 1/n.  相似文献   

11.
A k-ε-kp multi-fluid model was used to simulate confined swirling gas-solid two phase jet comprised of particle-laden flow from a center tube and a swirling air stream entering the test section from the coaxial annular. After considering the drag force between the two phases and gravity, a series of numerical simulations of the two-phase flow of 30μm, 45μm, 60μm diameter particles were performed on a x×r=50×50 mesh grid respectively. The results showed that the k-ε-kp multi-fluid model can be applied to predict moderate swirling multi-phase flow. When the particle diameter is large, the collision of the particles with the wall will influence the prediction accuracy. The bigger the diameter of the particles, the stronger the collision with the wall, and the more obvious the difference between measured and calculated results.  相似文献   

12.
In iron ore sintering, the granulation process is the first and an important step. As the fine particles adhere to the coarse coke particles, the NO x emission generated from coke combustion may be expected to be influenced by that adhering layer. In this study, the granule size distributions and adhering ratios were evaluated by a granulation model. Granulation experiments were also carried out to obtain the granule size distribution and adhering ratio. The influence of the adhering layer on NO x emissions from the combustion of S type granules was studied by tube furnace experiments. Conclusions include: (1) The adhering ratio predicted from the granulation model can be used as a qualitative index for the evaluation of NO x emission from coke combustion. (2) The influence of the adhering layer on NO x emissions was enhanced with increasing adhering layer thickness of S type granules, and the NO x reduction was enhanced at higher temperatures (around 1373 K), but weakened at lower temperatures (around 1173 K).  相似文献   

13.

Objective

To investigate a possible association between common variations of the P2RY12 and the residual clopidogrel on-treatment platelet reactivity after adjusting for the influence of CYP2C19 tested by thromboelastography (TEG).

Methods

One hundred and eighty patients with acute coronary syndrome (ACS) treated with clopidogrel and aspirin were included and platelet function was assessed by TEG. Five selected P2RY12 single nucleotide polymorphisms (SNPs; rs6798347, rs6787801, rs6801273, rs6785930, and rs2046934), which cover the common variations in the P2RY12 gene and its regulatory regions, and three CYP2C19 SNPs (*2,*3,*17) were genotyped and possible haplotypes were analyzed.

Results

The high on-treatment platelet reactivity (HTPR) prevalence defined by a platelet inhibition rate <30% by TEG in adenosine diphosphate (ADP)-channel was 69 (38.33%). Six common haplotypes were inferred from four of the selected P2RY12 SNPs (denoted H0 to H5) according to the linkage disequilibrium R square (except for rs2046934). Haplotype H1 showed a significantly lower incidence of HTPR than the reference haplotype (H0) in the total study population while haplotypes H1 and H2 showed significantly lower incidences of HTPR than H0 in the nonsmoker subgroup after adjusting for CYP2C19 effects and demographic characteristics. rs2046934 (T744C) did not show any significant association with HTPR.

Conclusions

The combination of common P2RY12 variations including regulatory regions rather than rs2046934 (T744C) that related to pharmacodynamics of clopidogrel in patients with ACS was independently associated with residual on-clopidogrel platelet reactivity. This is apart from the established association of the CYP2C19. This association seemed more important in the subgroup defined by smoking.
  相似文献   

14.
An extracellular β-glucosidase produced by Aspergillus terreus was identified, purified, characterized and was tested for the hydrolysis of soybean isoflavone. Matrix-assisted laser desorption/ionization with tandem time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) revealed the protein to be a member of the glycosyl hydrolase family 3 with an apparent molecular mass of about 120 kDa. The purified β-glucosidase showed optimal activity at pH 5.0 and 65 °C and was very stable at 50 °C. Moreover, the enzyme exhibited good stability over pH 3.0–8.0 and possessed high tolerance towards pepsin and trypsin. The kinetic parameters Km (apparent Michaelis-Menten constant) and Vmax (maximal reaction velocity) for p-nitrophenyl-β-d-glucopyranoside (pNPG) were 1.73 mmol/L and 42.37 U/mg, respectively. The Km and Vmax for cellobiose were 4.11 mmol/L and 5.7 U/mg, respectively. The enzyme efficiently converted isoflavone glycosides to aglycones, with a hydrolysis rate of 95.8% for daidzin, 86.7% for genistin, and 72.1% for glycitin. Meanwhile, the productivities were 1.14 mmol/(L·h) for daidzein, 0.72 mmol/(L·h) for genistein, and 0.19 mmol/(L·h) for glycitein. This is the first report on the application of A. terreus β-glucosidase for converting isoflavone glycosides to their aglycones in soybean products.  相似文献   

15.
Thin-walled spread foundations are used in coastal projects where the soil strength is relatively low. Developing a predictive model of bearing capacity for this kind of foundation is of interest due to the fact that the famous bearing capacity equations are proposed for conventional footings. Many studies underlined the applicability of artificial neural networks (ANNs) in predicting the bearing capacity of foundations. However, the majority of these models are built using conventional ANNs, which suffer from slow rate of learning as well as getting trapped in local minima. Moreover, they are mainly developed for conventional footings. The prime objective of this study is to propose an improved ANN-based predictive model of bearing capacity for thin-walled shallow foundations. In this regard, a relatively large dataset comprising 145 recorded cases of related footing load tests was compiled from the literature. The dataset includes bearing capacity (Qu), friction angle, unit weight of sand, footing width, and thin-wall length to footing width ratio (Lw/B). Apart from Qu, other parameters were set as model inputs. To enhance the diversity of the data, four more related laboratory footing load tests were conducted on the Johor Bahru sand, and results were added to the dataset. Experimental findings suggest an almost 0.5 times increase in the bearing capacity in loose and dense sands when Lw/B is increased from 0.5 to 1.12. Overall, findings show the feasibility of the ANN-based predictive model improved with particle swarm optimization (PSO). The correlation coefficient was 0.98 for testing data, suggesting that the model serves as a reliable tool in predicting the bearing capacity.  相似文献   

16.
Establishing an accurate in situ stress field is important for analyzing the rock-mass stability of the underground cavern at the Huangdeng hydropower station in China. Because of the complexity and importance of the in situ stress field, existing back analysis methods do not provide the necessary accuracy or sufficiently recognize nonlinear relations between the distribution of the in situ stress field and its formative factors. Those factors are related to the geological structures of high compressive tectonic stress regimes, including geological faults and tuff interlayers. The new two-stage optimization algorithm proposed in this paper is a combination of stepwise regression (SR), difference evolution (DE), support vector machine (SVM), and numerical analysis techniques. Stepwise regression is used to find the set of unknown parameters that best match the modeling prediction and determine the range of parameters to be recognized. Difference evolution is used to determine the optimum parameters of the SVM. The SVM is used to create the DE-SVM nonlinear reflection model to obtain the optimal values of the parameters from measured stress data. We compare the new two-stage optimization algorithm to other two popular methods, a multiple linear regression (MLR) analysis method and an artificial neural network (ANN) method, to estimate the in situ stress field for the actual underground cavern at the Huangdeng hydropower station. The two-stage optimization algorithm produces a more realistic estimate of the stress distribution within the investigated area. Thus, this technique may have practical applications in realistic scenarios requiring efficient and accurate estimations of the in situ stress in a rock-mass.  相似文献   

17.
The objective of this study was to describe the fecal microbiota succession of piglets from birth to post-weaning by pyrosequencing. The dominant bacterial phyla were Bacteroidetes, Firmicutes, Proteobacteria, and Fusobacteria, although the composition of the fecal microbiota changed as the piglets grew. Bacteroides, Parabacteroides, Prevotella, Lactobacillus, unclassified Lachnospiraceae, Ruminococcus, Oscillospira, Phascolarctobacterium, and Desulfovibrio were the core genera in the feces of piglets and existed from birth to post-weaning. Bacteroides was the most abundant at birth; however, the proportion of Bacteroides decreased as the piglets aged, while the proportion of Prevotella increased until it became the most abundant genus at the post-weaning stage. Principal coordinate analysis indicated that the microbial communities of piglet fecal samples from birth to post-weaning could be separated into four groups according to the similarity of community composition. These corresponded to time points on day 0 (birth); day 7; days 14, 21, and 28 (pre-weaning); and day 35 (post-weaning). This study suggests that the development of the intestinal microbiota in the piglet is a gradual and sequential process. This methodology establishes a basis for broader studies to investigate the microbiota of the piglet intestinal tract.  相似文献   

18.

Objective

To investigate the effects of corneal thickness distribution and apex position on postoperative refractive status after full-bed deep anterior lamellar keratoplasty (FBDALK).

Methods

This is a retrospective analysis of patients who were diagnosed with advanced keratoconus between 2011 and 2014 in our hospital. The base of the cone in all patients did not exceed the central cornea at a 6-mm range. The FBDALK was performed by a same surgeon. All patients had a complete corneal suture removal and the follow-up records were intact. Patients who had graft-bed misalignment or who were complicated with a cataract or glaucoma were excluded. Uncorrected visual acuity (UCVA), best spectacle corrected visual acuity (BSCVA), and Pentacam examination data were recorded at two years postoperatively. The recorded data included the superior-inferior (S-I) and nasal-temporal (N-T) corneal thickness differences in 2, 4, 6, and 8 mm diameter concentric circles with the corneal apex as the center (S-I2 mm, S-I4 mm, S-I6 mm, S-I8 mm, N-T2 mm, N-T4 mm, N-T6 mm, and N-T8 mm), the linear, X-axis, and Y-axis distance between the corneal pupillary center and the cornea apex, total corneal astigmatism at a zone of 3 mm diameter from the corneal apex (TA3 mm), the astigmatic vector values J0 and J45, and the corneal total higher-order aberration for 3 and 6 mm pupil diameters (HOA3 mm and HOA6 mm). Statistical analysis was performed by SPSS 15.0.

Results

A total of 47 eyes of 46 patients met the criteria and were included in this study. The mean follow-up time was (28±7) months. The mean UCVA was 0.45±0.23 (logMAR) (MAR: minimum angle of resolution) and the mean BSCVA was 0.19±0.15 (logMAR), which were all significantly positively correlated with postoperative TA3 mm and HOA3 mm. The mean S-I corneal thickness differences were (44.62±37.74) μm, and the mean N-T was (38.57±32.29) μm. S-I2 mm was significantly positively correlated with J0 (r=0.31), J45 (r=0.42), HOA3 mm (r=0.37), and HOA6 mm (r=0.48). S-I4 mm and S-I8 mm were significantly positively correlated with HOA3 mm (r=0.30, r=0.40) and HOA6 mm (r=0.46, r=0.35). The X-axis distance between corneal pupillary center and corneal apex was significantly positively correlated with J45 (r=0.29).

Conclusions

In patients with advanced keratoconus after FBDALK, the unevenly distributed thickness at corneal pupillary area and the misalignment of corneal apex and pupillary center might cause significant regular and irregular astigmatism, which affected the postoperative visual quality.
  相似文献   

19.
Non-dispersive solvent extraction (NDSE) with p-xylene as extractant was employed as a novel separation method to recover both p-toluic (PT) acid and water from purified terephthalic acid (PTA) wastewater. The mass transport behavior of PT acid from aqueous solution to p-xylene was investigated by experiments and numerical simulation. Experiments showed that NDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewater re-use (100 g/m3) with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transport was developed to optimize the membrane module performance. The model was validated with the experimental results with relative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and the shell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects of the membrane and operating parameters on membrane module performance were investigated by means of computational simulations. The key parameters suggested for industrial NDSE design are: fiber inner radius r1=200–250 µm, extraction time te=50–60 s, aqueous/organic volumetric ratio a/o=9.0, and temperature T=318 K.  相似文献   

20.
A Gram-negative, aerobic, non-motile, rod-shaped bacterial strain, designated 25-1T, was isolated from the air inside giant panda enclosures at the Chengdu Research Base of Giant Panda Breeding, China. Strain 25-1T grew optimally at pH 7.0–8.0, at 28–30 °C and in the presence of NaCl concentrations from 0.0% to 0.5 %. 16S rRNA gene sequence analysis indicated that strain 25-1T belongs to the genus Chryseobacterium within the family Flavobacteriaceae and is related most closely to C. carnis G81T (96.4% similarity), C. lathyri RBA2-6T (95.8% similarity), and C. zeae JM1085T (95.8% similarity). Its genomic DNA G+C molar composition was 36.2%. The major cellular fatty acids were iso-C15:0 (44.0%), iso-C17:0 3OH (19.8%) and C16:1 ω7c/16:1 ω6c (12.7%). The only isoprenoid quinone was menaquinone 6 (MK-6). The major polar lipids were phosphatidylethanolamine, two unidentified amino lipids and two unidentified lipids. The DNA-DNA relatedness between strain 25-1T and C. lathyri RBA2-6T was 38%. Phenotypic, genotypic, and phylogenetic characteristics indicated that strain 25-1T is a novel member of the genus Chryseobacterium, for which the name C. chengduensis sp. nov. is proposed. The type strain is 25-1T (CCTCC AB2015133T=DSM 100396T).  相似文献   

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