1,293 research outputs found
Share Pledging and Firm Cash Holdings: Evidence from Chinese A-share Listed Firms
This paper examines the relation between share pledging and cash holdings of Chinese A-share listed-firms. We find that during the years 2005 through 2015, the level of share pledging is negatively associated with cash holdings. We establish causality through a variety of econometric techniques, including a difference-in-differences approach based on a regulatory change that permits security companies to lend money to borrowers pledging their shares as collaterals. In addition, we find that the main effect is more prominent for financial constrained firms, and share pledging is associated with lower cash/investment-cash flow sensitivities and more cash dividend payouts. Overall, our findings indicate that share pledging can alleviate financial constraints of listed firms and reduce their tendencies of holding cash for precautionary motives
Preparation and Micro Mechanical Properties of Nano-Al2O3 Particles Strengthened Ni-based Composite Coatings
AbstractNi-based composite solution containing nano-Al2O3 particles was prepared by high-energy mechanical and chemical processes. The microstructure and nano-particle content of nano-Al2O3/Ni composite coatings were determined by SEM, EDS and TEM. The micro mechanical properties were tested by nano-indentation technique, and the strengthening mechanism was analyzed. The results show that 85 percent of particles in the solution are dispersed in size of nano meter, nano-particles co-deposited in the coating increases by a factor of 53 percent and the structure of the composite coating is more compact and uniform than that of Ni coating. Nano-Al2O3/Ni coatings exhibit excellent micro mechanical properties, the nanohardness and Young's modulus are 7.04GPa and 225GPa respectively, which are attributed to finer crystals strengthening, dispersion strengthening and high- density dislocations strengthening
Retinoic acid liposome-hydrogel: preparation, penetration through mouse skin and induction of F9 mouse teratocarcinoma stem cells differentiation
Retinoic acid (RA), a metabolite of retinol, is one of the most biologically active forms of retinoid and plays vital roles in embryonic development and in the regulation of cell proliferation and differentiation. Knowing that liposomes simulate cell membranes and that hydrogel is an ideal delivery vehicle for topical medicine, liposome-hydrogel is a novel preparation that has synergistic advantages over each component separately. Our objective was to investigate the characteristics of RA liposome-hydrogel. For quality control of the RA-loaded liposomes, we measured their morphology, particle size, Zeta-potential, and entrapment efficiency. Then we determined the viscosity of RA liposome-hydrogel. Next, the diffusion through mouse skin was explored, followed by investigation of the mRNA expression levels of Ker18, REX1, and α-FP using Q-PCR. The results showed that RA liposome-hydrogel penetrates the mouse skin effectively. The permeation rates were: Qn (%) of RA liposome-hydrogel < Qn(%) of RA-loaded liposome < Qn (%) of RA. The mRNA expression levels were dose-dependent and the effective dose decreased between vehicles due to their different release rates. F9 mouse teratocarcinoma stem cells were an ideal model to explore the mechanism of RA liposome-hydrogel in stem cell differentiation.O ácido retinóico (RA) é um metabolito de retinol. Ele também é uma das formas mais biologicamente ativas de retinóide. Desempenha papel vital no desenvolvimento embrionário e na regulação da proliferação e diferenciação celular. Sabendo-se que lipossomas simulam a membrana das células e que hidrogel é um sistema ideal para o medicamento tópico, o lipossoma-hidrogel é uma nova preparação, que apresenta vantagens sinérgicas em relação a cada um dos componentes separados. Nosso objetivo foi investigar as características de RA lipossoma-hidrogel. A fim de controlar a qualidade do lipossoma carregado com RA, medimos morfologia, tamanho das partículas, potencial zeta e eficiência de retenção. Em seguida, determinou-se a viscosidade de RA lipossoma-hidrogel. Em seguida, avaliou-se a sua difusão através da pele de camundongos, seguida da investigação dos níveis da expressão de mRNA de Ker18, REX e de α-FP, utilizando-se Q-PCR. Os resultados mostraram que RA lipossoma-hidrogel pode penetrar na pele do camundongo de forma eficaz. As taxas de permeação foram: Qn (%) de RA lipossoma-hidroge
Effects of distance from home to campus on undergraduate place attachment and university experience in China
First-year students in transition from hometown to campus are generally confronted by intellectual and social challenges as well as disruption and the formation of the place attachments associated with relocation. Understanding the variables affecting student place attachment helps address the widespread concern about student transition. Interactions between place attachment to hometown and campus, and the effects of endogenous and exogenous variables on place attachments, were analysed using covariance analysis, based on questionnaire data gathered at a Chinese university. Campus identity acts as a predictor for the other three dimensions of place attachment to hometown and campus: hometown identity, hometown dependence and campus dependence. Place attachment to campus exerts a direct effect on place attachment to hometown, while the latter indirectly impacts on the former through mediators including academic self-efficacy and peer relationships. Gender, household registration record and duration of dormitory stay were also identified as statistically significant predictors of student place attachment
Do the Characteristics of Independent Directors and Supervisory Board Members Matter in China?
This paper investigates and compares the characteristics of independent directors and supervisory board members in Chinese listed firms. The occupational backgrounds of independent directors and supervisory board members in listed firms are very different. Besides, different firms have different preferences in employing independent directors and supervisory board members according to their demands. Moreover, the empirical results show that characteristics of independent directors and supervisory board members have no clear relationship with firm performance. No matter their professional backgrounds or age, the independent directors and supervisory board members do not have the authority to affect the decision making process of management. Thus they cannot really contribute to firm performance
Fine Particulate Matter Constituents and Cardiopulmonary Mortality in a Heavily Polluted Chinese City
Background: Although ambient fine particulate matter (PM2.5; particulate matter ≤ 2.5 µm in aerodynamic diameter) has been linked to adverse human health effects, the chemical constituents that cause harm are unknown. To our knowledge, the health effects of PM2.5 constituents have not been reported for a developing country
Accelerated phosphorus accumulation and acidification of soils under plastic greenhouse condition in four representative organic vegetable cultivation sites
Author Posting. © The Author(s), 2015. This is the author's version of the work. It is posted here by for personal use, not for redistribution. The definitive version was published in Scientia Horticulturae 195 (2015): 67-83, doi:10.1016/j.scienta.2015.08.041.Organic vegetable cultivation under plastic greenhouse conditions is expanding rapidly in the
suburb of big cities in China due to the increasing demand for organic, out-of-season green
vegetables and the sustainable development of agriculture. Phosphorus (P) is not only an important
plant nutrient, but also a major contaminant in the water environment. However, information on the
accumulation and distribution of P in organic vegetable soils under plastic greenhouse conditions is
limited, relative to the open cultivation systems. Therefore, twenty-six plastic greenhouse vegetable
soils (PGVS) were selected randomly from four representative organic vegetable cultivation sites
located in the suburb of Nanjing, China. For comparison, 15 open vegetable soils (OVS) near the
PGVS with similar soil and cultivation practices were selected. Soil pH, organic matter (OM) and
the various P accumulation characteristics were investigated. We found that soil pH in PGVS were
significantly decreased by 0.57~1.17 unit with obvious signs of acidification, compared with that in
OVS. Soil OM was different for different sampling locations, but in general it was higher in PGVS
than OVS. Soil total P (TP), inorganic P (Pi) and Olsen-P of PGVS were higher than those in the
OVS. Olsen-P of all soil samples were far above the recommended optimum value of 20 mg kg-1 for
field crops, and over 60% soil samples were considered excessive (>150 mg kg-1 ) in the PGVS and
OVS. There were significant correlations between total P, available P and soil pH in those vegetable
soils. Al-P/Fe-P ratio was also significantly correlated with vegetable soil pH (YpH = 7.44 - 1.32
XAl-P/Fe-P, r = - 0.705, p < 0.01). Soil total Pi was negatively correlated with soil pH in vegetable
soils (r = -0.328, p < 0.05), but the interactive effect of soil various Pi and soil pH need to be further
investigated through a series of controlled tests. Our results suggest that the rapid P accumulation
and acidification make the current plastic greenhouse vegetable production in the study area
unsustainable and better organic manure management practices need to be implemented to sustain
crop yields while minimizing the impact of vegetable production on the environment.This work was supported by the National Natural Science Foundation, China (grant no.
41571286; 51479055); Open Research Fund Program of State Key Laboratory of Soil and
Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Science, Nanjing 210008,
China (grant no.Y412201419); and the Fund of Jiangsu Overseas Research & Training Program
for University Prominent Young & Middle-aged Teachers and Presidents
Correlations of synergistic effect of glucocorticoids on tacrolimus with CYP3A, MDR1 and PXR gene polymorphisms in pediatric patients receiving liver transplantation for malignancy and chronic liver disease
Immune suppression after liver transplant for malignancy, such as hepatocellular carcinoma and end stage liver disease is done using immunosuppressant drugs like tacrolimus. As the immune system in children is not fully developed, combining immunosuppressants like glucocorticoids influence the efficacy and reduce the chances of transplant rejection, particularly in patients with gene polymorphism. However, whether interaction between glucocorticoid and tacrolimus is associated with CYP3A, MDR1, and PXR gene polymorphisms, remains unclear. Here, we explored correlations of synergistic effect of glucocorticoids on tacrolimus with CYP3A, MDR1 and PXR gene polymorphisms in pediatric patients receiving liver transplantation for malignancy and chronic liver disease. A total of 340 eligible children were divided into glucocorticoid (+) (n=148) and glucocorticoid () groups (n=192). They were given tacrolimus + mycophenolate mofetil, based on which glucocorticoid (+) group took prednisone acetate tablets for ≥12 months. The blood trough concentration of tacrolimus was detected by chemiluminescence microparticle immunoassay 1, 3, 6 and 12 months after medication, and blood drug concentration corrected by daily concentration/daily dose (C0/D) was calculated. CYP3A, MDR1 and PXR gene polymorphisms were analyzed using PCR-RFLP. GG, AG and AA genotypes of CYP3A were observed in 130, 166 and 44 cases, respectively. CC, CT and TT genotypes of MDR1 were found in 152, 142 and 46 cases, respectively. There were 252, 74 and 14 cases of WW, WM and MM genotypes of PXR, respectively. The distribution frequencies of GG and AG+AA genotypes had significant differences between the two groups. One month after medication, C0/D of tacrolimus of GG genotype in glucocorticoid (+) group significantly exceeded that of glucocorticoid () group. C0/D was significantly higher in glucocorticoid (+) group with AG+AA genotype1, 3, 6 and 12 months after medication (P <0.05)
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