36 research outputs found

    Reaction kinetics of cassava starch graft anionic/nonionic-type polymer internal curing agents

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    Internal curing can help to improve the durability of concrete by preventing and minimizing initial cracks due to autogenous shrinkage and plastic shrinkage. Using a reliable internal curing agent is essential to the effectiveness of the internal curing process. This paper investigates the reaction kinetics of a starch graft anionic/nonionic-type polymer. The results demonstrate that initiator monomer concentration, and starch concentration are positively correlated with graft reaction rate Rp. Based on the research, the kinetics equation of this cassava starch graft anionic/nonionic-type polymer has also been developed, which coincides well with the law of free radical polymerization. The obtained Rp equation is a first-order dependence of the monomer concentration and the square root of the initiator concentration. And Rp is further correlated to the reaction temperature based on a sigmoid function instead of a linear function. It is also found that the polymerization reaction is characterized by the coexisted disproportion termination and coupling termination

    Human CIK Cells Loaded with Au Nanorods as a Theranostic Platform for Targeted Photoacoustic Imaging and Enhanced Immunotherapy and Photothermal Therapy

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    How to realize targeted photoacoustic imaging, enhanced immunotherapy, and photothermal therapy of gastric cancer has become a great challenge. Herein, we reported for the first time that human cytokine-induced killer cells (CIK) loaded with gold nanorods were used for targeted photoacoustic imaging, enhanced immunotherapy, and photothermal therapy of gastric cancer. Silica-modified gold nanorods were prepared; then incubated with human cytokine-induced killer cells (CIK), resultant human CIK cells loaded with Au nanorods were evaluated for their cytotoxicity, targeted ability of gastric cancer in vitro and in vivo, immunotherapy, and photothermal therapy efficacy. In vitro cell experiment shows that human CIK cells labeled with gold nanorods actively target gastric cancer MGC803 cells, inhibit growth of MGC803 cells by inducing cell apoptosis, and kill MGC803 cells under low power density near-infrared (NIR) laser treatment (808-nm continuous wave laser, 1.5 W/cm2, 3 min). In vivo experiment results showed that human CIK cells labeled with gold nanorods could target actively and image subcutaneous gastric cancer vessels via photoacoustic imaging at 4 h post-injection, could enhance immunotherapy efficacy by up-regulating cytokines such as IL-1, IL-12, IL-2, IL-4, IL-17, and IFN-γ, and kill gastric cancer tissues by photothermal therapy via direct injection into tumor site under near-infrared (NIR) laser irradiation. High-performance human CIK cells labeled with Au nanorods are a good novel theranostic platform to exhibit great potential in applications such as tumor-targeted photoacoustic imaging, enhanced immunotherapy, and photothermal therapy in the near future

    Leaf emergence in relation to leaf traits in temperate woody species in East-Chinese Quercus fabri forests

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    To determine the effect of leaf traits on leaf emergence phenology, timing of leaf emergence, leaf expansion rate, durations of leaf emergence and expansion, leaf mass per area (LMA) and leaf size were investigated for 48 woody species from 25 families in two closed Chinese white oak (Quercus fabri) forests of eastern China. Cross-species regression and phylogenetic regression were employed to examine the relationship between leaf phenology and leaf traits. Leaf area, LMA, and leaf expansion rate were found to be significantly greater in canopy trees than in understory shrubs in the oak forests. However, there was no significant difference in timing of leaf emergence and durations of leaf emergence and expansion between canopy and understory species. The large-LMA species leafed out earlier than the species with small LMA. The small-leaved species leafed out earlier than the species with large leaves, but the large-leaved species were greater in leaf expansion rate than their counterparts. Leaf expansion rate was positively correlated with leaf area and timing of leaf emergence, but no significant relationship was found between leaf size and leaf expansion period. These results suggest that large- and small-leaved species possibly employed different strategies to minimize herbivory damage, i.e. early leafing to avoid defoliator damage in small-leaved species and fast expanding and thereby shortening vulnerable time to herbivores in large-leaved species. It could be inferred that the species with small leaves and large-LMA leafed out early in the oak forests, thereby permitting less energy loss than their counterparts under the influence of frost in early spring. In general, early leaf emergence is of significance for high LMA species to increase carbon gain in temperate broad-leaved forests, but it is not related to plant height. Leaf size and leaf expansion period are not necessarily correlated

    The Chemical Signatures of Water Extract of Zingiber officinale Rosc

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    Background: Ginger (Z. officinale Rosc.) is a common herb and is widely used as a diet-based or home therapy in traditional medicine worldwide. However, fresh ginger turns into dried ginger after kiln drying and shows a different treatment effect in clinical practice. Objective: To characterize the changes of major bioactive constituents in dried ginger after the processing of fresh ginger. Methods: A novel, ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UHPLC–QTOF/MS) method was established to characterize the changes in the bioactive constituents of dried ginger. The novel strategy was split into two steps: firstly, the MS selected the most intense precursor ions of tandem MS; then, target MS/MS acquisition with different collision energies (10, 20, and 40 eV) was used to characterize the compound’s accurate MS/MS spectra and compare the MS/MS spectrum with the building MS reference library and reference standards. Result: Fifty-three compounds, including diarylheptanoids, gingerols, gingerodiols, gingerdiones, and shogaol-related compounds, were identified based on summarized fragmentation patterns. Fifteen out of fifty-three compounds were diarylheptanoids, which was different from fresh ginger. Conclusion: These identified compounds could be used to characterize the quality of dried ginger, pharmacologic studies should focus on diarylheptanoids explaining the different treatment effects between fresh ginger and dried ginger

    Regional Sustainable Strategy Based on the Coordination of Ecological Security and Economic Development in Yunnan Province, China

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    Coordination between ecological security and economic development is crucial to sustainable development, with a development strategy that should be adjusted according to the type of region. Yunnan Province, China, is a treasure trove of biodiversity but is economically lagging. Clarifying the relationship between ecological security and economic development can provide a reference for the sustainable development of similar biodiversity hotspots in the world. The landscape index method and index evaluation method were used to calculate the ecological safety index (ESI) and the economic development index (EDI), respectively, and the median value of the indices was used for the comprehensive zoning. The coupled coordination degree model (CCDM) was used to assess the coordination status of ecological safety and economic development in each zone. The results show that (1) Yunnan’s ecological security pattern is high in the west and low in the east, mainly influenced by topography, climate, and human activities; its economic development is resource-dependent and shows a multi-point dispersed pattern due to poor transportation; (2) Yunnan was partitioned into the Coordinated Development Zone (CDZ), the Ecological Risk Zone (ERZ), the Economic Poverty Zone (EPZ), and the Dual Pressure Zone (DPZ). Among them, CDZs (15%) are mostly areas with outstanding advantageous resources, mature characteristic industries, and relatively spatially dispersed. There are two types of ERZs (35%): one is an area where the intensity of human activities exceeds the ecological carrying capacity, mainly located in the eastern plateau; the other is an area with fragile ecological background conditions, located in high mountains and river valleys. EPZs (35%) are mainly lagging in socioeconomics of DPZ (15%) and the fragile ecological environment constrains each to form a negative cycle. (3) Of the regional coordination levels in Yunnan Province, 76% are moderately coordinated, and there is still space for development from the high-quality coordination level. The order of the average coordination degree of each partition is CDZ > ERZ > EPZ > DPZ. The poor basis for coordination and the single approach to coordination have led to ecological safety and economic development often being more difficult to achieve in areas with large mountainous areas similar to Yunnan. (4) Due to the necessity for biodiversity protection, Yunnan Province should choose the sustainable path of ecological priority and green development. Specifically, CDZ should play to industrial advantages and brand effects, and promote industrial integration and innovative industrial development paths. The keys to ERZ are industrial restructuring, industrial ecologization, and ecological environment restoration and protection. EPZ should improve transportation and other infrastructure and revitalize economic development under the premise of ecological priority. Finally, DPZ should emphasize human and load reduction, and moderate development

    Research on the Progress of Agricultural Non-Point Source Pollution Management in China: A Review

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    In the 1980s, China began to recognize the gravity of the problem of non-point agricultural source pollution and conduct research on it. Agricultural non-point source pollution in China, on the other hand, differs from foreign agricultural non-point source pollution and industrial point source pollution. Because the features of agricultural non-point source pollution are complicated, it is critical to investigate a whole-chain management policy system appropriate for China’s agricultural pattern. Based on the current situation of agricultural non-point source pollution in China, this study summarizes the four stages of agricultural non-point source pollution prevention and control policies, namely the discovery stage with macro policies as the main focus, the exploration stage with single research indicators, the initial systematic strengthening stage, and the focused stage with targeted characteristics. Simultaneously, it examined the technological approaches that are suitable for China’s national circumstances and have been investigated by relying on international experience in present-day Chinese management. However, there are still some problems and challenges in agricultural non-point source pollution management policies, such as a lack of non-point source information support, a lack of coordination between different departments, a lack of support in measurement and retroactive calculation and treatment, a lack of an in-depth concept of zoning and classification, a lack of policy, an institutional system, and insufficient capital investment. Based on these problems and combining them with Green Agriculture, Beautiful China, and other goals, this paper puts forward suggestions to strengthen the policy data support of the agricultural non-point source pollution management system, enhance the research and development of the law of pollutant migration and transformation, encourage the innovation of low-cost and high-benefit treatment technology, improve the construction of the management system, strengthen the collaboration of departments, increase the investment of funds, and make other suggestions so as to promote the treatment of agricultural non-point source pollution with high quality and efficiency

    Age-and Region-Dependent Disposition of Raloxifene in Rats

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    Purpose: Raloxifene undergoes extensive glucuronidation in the gastrointestinal (GI) tract and the liver. However, the impact of age on raloxifene disposition has never been studied. The purpose of this paper is to determine glucuronidation and Pharmacokinetics (PK) profiles of raloxifene in rats at different ages. Methods: Raloxifene glucuronidation was characterized using S9 fractions prepared from different intestinal segments and the liver of F344 rats at 4-, 11-, and 28-week. PK studies were conducted to determine raloxifene oral bioavailability at different ages. Raloxifene and its glucuronides were quantified using LC-MS/MS. Results: Raloxifene-6-glucuronide and raloxifene-4′-glucuronide were detected as the major metabolites and the ratio of these two glucuronides were different ranging from 2.1 to 4.9 folds in the ileum, jejunum, liver, and duodenum, and from 14.5 to 50 folds in the colon. The clearances in the duodenum at 4-week for both two glucuronides were significantly lower than those at the other two ages. PK studies showed that the oral bioavailability of raloxifene is age dependent. The absolute oral bioavailability of raloxifene was 3.5-folds higher at 4-week compared to that at 11-weeks. When raloxifene was administered through IV bolus, its half-life was 5.9 ± 1.16 h and 3.7 ± 0.68 h at 11-and 4-week, respectively. Conclusion: These findings suggested that raloxifene metabolism in the duodenum was significantly slower at young age in rats, which increased the oral bioavailability of raloxifene. At 11-week, enterohepatic recycling efficiency was higher than that of 4-week. Raloxifene’s dose at different ages should be carefully considered

    A positive–negative switching LC-MS/MS method for quantification of fenoldopam and its phase II metabolites: Applications to a pharmacokinetic study in rats

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    Fenoldopam is an approved drug used to treat hypotension. The purpose of this study is to develop and validate an LC-MS method to quantify fenoldopam and its major metabolites fenoldopam-glucuronide and fenoldopam-sulfate in plasma and apply the method to a pharmacokinetic study in rats. A Waters C18 column was used with 0.1% formic acid in acetonitrile and 0.1% formic acid in water as the mobile phases to elute the analytes. A positive–negative switching method was performed in a triple quadrupole mass spectrometer using Multiple Reaction Monitoring (MRM) mode. A one-step protein precipitation using methanol and ethyl acetate was successfully applied for plasma sample preparation. The method was validated following the FDA guidance. The results show that the LLOQ of fenoldopam, fenoldopam-glucuronide and fenoldopam-sulfate is 0.98, 9.75 and 0.98 nM, respectively. The intraday and interday variance is less than 8.4% and the accuracy is between 82.5 and 116.0 %. The extraction recovery for these three analytes ranged from 81.3 ± 4.1% to 113.9 ± 13.2%. There was no significant matrix effect and no significant degradation under the experimental conditions. PK studies showed that fenoldopam was rapidly eliminated (t1/2 = 0.63 ± 0.24 h) from the plasma and glucuronide is the major metabolite. This method was suitably selective and sensitive for pharmacokinetic and phase II metabolism studies
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