91 research outputs found
Controlled-Release Fertilizers as a Means to Reduce Nitrogen Leaching and Runoff in Container-Grown Plant Production
Container-grown plants refer to plants produced in confined volume filled with substrates. The substrates endogenously have limited nutrients and low water-holding capacity. Plants grown in the containers must be fertilized and watered frequently varying from daily to weekly. Frequent fertilization and irrigation can result in nutrient leaching and/or runoff. Since nitrogen (N) is a key component of the majority of fertilizers, container plant production has been viewed as a source of N leaching and/or runoff. The leaching and runoff, if in large quantities on a year-round basis, could affect surface and ground water quality. Application of controlled-release fertilizers (CRFs) has been reported to have less N leaching than plants fertilized with water-soluble fertilizers (WSFs). However, there are different types of CRFs with different compositions and longevities on the market. Container plants also differ greatly in their growth and development and in N requirement. Thus, production of high-quality container plants with minimum N leaching using CRFs still remains challenging. This article is intended to discuss characteristics of container plant production and N leaching and runoff during production, and to document that CRF application can reduce N leaching and/or runoff. Certain requirements for future development of CRFs are also discussed
China's New Third Board Market: Opportunities and Challenges
AbstractThe New Third Board Market is China's OTC market, established in 2006. Compared to China's Main Board Market and the Second Board Market, it attracts a lot of start-up companies needing financing with lower listing requirements. Meanwhile, it is full of opportunities and challenges that appeal to numerous securities traders and investors with the rapid development momentum. This paper is intended to build a comprehensive and systematic knowledge framework of China's New Third Board Market for those enterprises and individuals interested in it, and to provide a research base for future researchers
Gojiberry Breeding: Current Status and Future Prospects
Goji, gojiberry, or wolfberry is the fruit of Lycium barbarum L., L. chinense Mill., or L. ruthenicum Murr. in the family Solanaceae Juss. The fruit is bright orange-red or black and is edible with a sweet and tangy flavor. Gojiberry is rich in polysaccharides, flavonoids, carotenoids, betaine, kukoamine A, sitosterol, and other compounds which have antioxidant, anti-inflammatory, and anti-neoplastic properties and have been used for the treatment of various blood circulation disorders and diabetes. Recently, there is an increased demand for high-quality gojiberry and its products because they are considered a superfruit. China is the main producer and supplier of gojiberry in the world. Thus far, limited information is available about genetic resources, breeding activities, and major cultivars of gojiberry. This chapter is intended to review the current knowledge on gojiberry germplasm resources and their relationships as well as to describe gojiberry breeding activities. Future prospects on gojiberry cultivar development are also discussed
Effect of nitrogen, carbon sources and agitation speed on acetoin production of Bacillus subtilis SF4-3
Background: Currently, microbial fermentation method has become the
research hotspot for acetoin production. In our previous work, an
acetoin-producing strain, Bacillus subtilis SF4-3, was isolated from
Japanese traditional fermented food natto. However, its conversion of
glucose to acetoin was relatively low. In order to achieve a
high-efficient accumulation of acetoin in B. subtilis SF4-3, main
medium components and fermentation conditions were evaluated in this
work. Results: The by-products analysis showed that there existed
reversible transformation between acetoin and 2,3-butanediol that was
strictly responsible for acetoin production in B. subtilis SF4-3. The
carbon sources, nitrogen sources and agitation speed were determined to
play crucial role in the acetoin production. The optimal media
(glucose\ub7H2O 150 g/L, yeast extract 10 g/L, corn steep dry 5 g/L,
urea 2 g/L, K2HPO4 0.5 g/L, MgSO4 0.5 g/L) were obtained. Furthermore,
the low agitation speed of 300 r/min was found to be beneficial to the
reversible transformation of 2,3-butanediol for acetoin production in
B. subtilis SF4-3. Eventually, 48.9 g/L of acetoin and 5.5 g/L of
2,3-butanediol were obtained in a 5-L fermenter, and the specific
production of acetoin was 39.12% (g/g), which accounted for 79.90% of
the theoretical conversion. Conclusions: The results indicated
acetoin production of B. subtilis SF4-3 was closely related to the
medium components and dissolved oxygen concentrations. It also provided
a method for acetoin production via the reversible transformation of
acetoin and 2,3-butanediol
Comparisons of three polyethyleneimine-derived nanoparticles as a gene therapy delivery system for renal cell carcinoma
<p>Abstract</p> <p>Background</p> <p>Polyethyleneimine (PEI), which can interact with negatively charged DNA through electrostatic interaction to form nanocomplexes, has been widely attempted to use as a gene delivery system. However, PEI has some defects that are not fit for keeping on gene expression. Therefore, some modifications against PEI properties have been done to improve their application value in gene delivery. In this study, three modified PEI derivatives, including poly(Īµ-caprolactone)-pluronic-poly(Īµ-caprolactone) grafted PEI (PCFC-g-PEI), folic acid-PCFC-isophorone diidocyanate-PEI (FA-PEAs) and heparin-PEI (HPEI), were evaluated in terms of their cytotoxicity and transfection efficiency <it>in vitro </it>and <it>in vivo </it>in order to ascertain their potential application in gene therapy.</p> <p>Methods</p> <p>MTT assay and a marker GFP gene, encoding green fluorescent protein, were used to evaluate cell toxicity and transfection activity of the three modified PEI <it>in vitro</it>. Renal cell carcinoma (RCC) models were established in BALB/c nude mice inoculated with OS-RC-2 cells to detect the gene therapy effects using the three PEI-derived nanoparticles as gene delivery vehicles. The expression status of a target gene Von Hippel-Lindau (VHL) in treated tumor tissues was analyzed by semiquantitative RT-PCR and immunohistochemistry.</p> <p>Results</p> <p>Each of three modified PEI-derived biomaterials had an increased transfection efficiency and a lower cytotoxicity compared with its precursor PEI with 25-kD or 2-kD molecule weight <it>in vitro</it>. And the mean tumor volume was obviously decreased 30% by using FA-PEAs to transfer VHL plasmids to treat mice RCC models. The VHL gene expression was greatly improved in the VHL-treated group. While there was no obvious tumor inhibition treated by PCFC-g-PEI:VHL and HPEI:VHL complexes.</p> <p>Conclusions</p> <p>The three modified PEI-derived biomaterials, including PCFC-g-PEI, FA-PEAs and HPEI, had an increased transfection efficiency <it>in vitro </it>and obviously lower toxicities compared with their precursor PEI molecules. The FA-PEAs probably provide a potential gene delivery system to treat RCC even other cancers in future.</p
Downregulated expression of HSP27 in human low-grade glioma tissues discovered by a quantitative proteomic analysis
<p>Abstract</p> <p>Background</p> <p>Heat shock proteins (HSPs), including mainly HSP110, HSP90, HSP70, HSP60 and small HSP families, are evolutionary conserved proteins involved in various cellular processes. Abnormal expression of HSPs has been detected in several tumor types, which indicates that specific HSPs have different prognostic significance for different tumors. In the current studies, the expression profiling of HSPs in human low-grade glioma tissues (HGTs) were investigated using a sensitive, accurate SILAC (stable isotope labeling with amino acids in cell culture)-based quantitative proteomic strategy.</p> <p>Results</p> <p>The five HSP family members were detected and quantified in both HGTs and autologous para-cancerous brain tissues (PBTs) by the SILAC-based mass spectrometry (MS) simultaneously. HSP90 AB1, HSP A5(70 KDa), and especially HSP27 were significantly downregulated in HGTs, whereas the expression level of HSPA9 (70 KDa) was little higher in HGTs than that in PBTs. It was noted that the downregulation ratio of HSP27 was 0.48-fold in HGTs <it>versus </it>PBTs, which was further validated by results from RT-PCR, western blotting and immunohistochemistry. Furthermore, we detected HSP27 expression changes along with cell growth under heat shock treatment in glioma H4 cells.</p> <p>Conclusion</p> <p>The SILAC-MS technique is an applicable and efficient novel method, with a high-throughput manner, to quantitatively compare the relative expression level of HSPs in brain tumors. Different HSP family members have specific protein expression levels in human low-grade glioma discovered by SILAC-MS analysis. HSP27 expression was obviously downregulated in HGTs <it>versus </it>PBTs, and it exhibited temporal and spatial variation under heat shock treatment (43Ā°C/0-3 h) <it>in vitro</it>. HSP27's rapid upregulation was probably correlated with the temporary resistance to heat shock in order to maintain the survival of human glioma cells.</p
Nonlinear dynamic analysis of composite piezoelectric plates with graphene skin
This paper studies the nonlinear dynamical characteristic of a composite plate made of new three-phase materials which include the graphene (GP) combined with macro fiber composite (MFC) in the polymer. The GP is supposed to be uniformly dispersed in the upper and lower surfaces of the composite laminated plate with 1ā3 mode of macro fiber. The cross-ply MFC composite laminated plate is subjected to transversal excitations. The constitutive laws for the MFC-GP composite material are obtained based on the rule of mixture for multi-components of composite material. The nonlinear governing equations of motion of the MFC-GP plate are derived by Hamilton's principle and the von KĆ”rmĆ”n geometrical kinematics. Galerkin's approach is employed to discretize the partial differential governing equations into a two-degree-of-freedom nonlinear system. Then, stability analysis is conducted to investigate the influences of various parameters on natural frequencies of the MFC-GP plate, with a particular focus on the effects of GP volume fraction, initial conditions and damping coefficients on nonlinear vibration behaviours of the composite plate
Advances in Research on Water-in-Water Emulsions Based on the Stabilization Mechanism of Pickering Emulsions
Water-in-water emulsions, which have a very low interfacial tension and a thick interfacial layer, are formed by two thermodynamically incompatible hydrophilic macromolecules in a certain proportion. It has been reported that the system cannot be stabilized by surfactants, but can avoid macroscopic phase separation by gelation of one or two phases. Recently, it has been found that the stability of water-in-water emulsions can be improved by the irreversible adsorption of solid particles at the interface based on the stabilization mechanism of oil-in-water Pickering emulsions. In this review, we summarize recent advances in research on the stabilization of water-in-water emulsions, and focus on the stability of Pickering emulsions stabilized by solid particles and its influential factors, as well as its applications in the food field. It is expected that this review will provide new ideas for food structure design based on the stabilization of water-in-water emulsions
Advances in Gel Stability Improvement of Yoghurt
Yoghurt has high nutritional value and health-promoting functions; however, its quality defects such as whey syneresis and poor coagulation affect the sensory experience of consumers. Researchers commonly use food macromolecules to improve the gel stability and sensory properties of yoghurt by modifying the formation of gel networks or inducing the gelation of milk protein. In this review, we summarize the texture defects of yogurt, the factors influencing them, and the strategies to improve the gel stability of yogurt as well as the underlying mechanism. Also, we discuss future trends. This review will provide important guidance for improving the quality and stability of yoghurt products
Role of the tumor microenvironment in PD-L1/PD-1-mediated tumor immune escape
Tumor immune escape is an important strategy of tumor survival. There are many mechanisms of tumor immune escape, including immunosuppression, which has become a research hotspot in recent years. The programmed death ligand-1/programmed death-1 (PD-L1/PD-1) signaling pathway is an important component of tumor immunosuppression, which can inhibit the activation of T lymphocytes and enhance the immune tolerance of tumor cells, thereby achieving tumor immune escape. Therefore, targeting the PD-L1/PD-1 pathway is an attractive strategy for cancer treatment; however, the therapeutic effectiveness of PD-L1/PD-1 remains poor. This situation requires gaining a deeper understanding of the complex and varied molecular mechanisms and factors driving the expression and activation of the PD-L1/PD-1 signaling pathway. In this review, we summarize the regulation mechanisms of the PD-L1/PD-1 signaling pathway in the tumor microenvironment and their roles in mediating tumor escape. Overall, the evidence accumulated to date suggests that induction of PD-L1 by inflammatory factors in the tumor microenvironment may be one of the most important factors affecting the therapeutic efficiency of PD-L1/PD-1 blocking
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