Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:...Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:1. The second hypothesis was that increasing dietary Ca increases plasma Ca concentration and downregulates abundance of genes related to Ca absorption(TRPV6, S100 G, and ATP2 B1) in the duodenum, and tight junction proteins(OCLN, CLDN1, and ZO1) in the duodenum and ileum.Methods: Twenty corn-soybean meal diets were formulated using a 4 × 5 factorial design with diets containing 0.16%, 0.33%, 0.42%, or 0.50% STTD P, and 0.14%, 0.29%, 0.44%, 0.59%, or 0.74% STTD Ca. Six hundred and forty pigs(initial weight: 11.1 ± 1.4 kg) were allotted to 20 diets and 5 blocks in a randomized complete block design. On day21, weights of pigs and feed left in feeders were recorded and blood, duodenal tissue, ileal mucosa, and the right femur were collected from 1 pig per pen. Abundance of m RNA was determined in duodenal and ileal tissue via quantitative RT-PCR. Data were analyzed using a response surface model.Results: The predicted maximum ADG(614 g), G:F(0.65), and bone ash(11.68 g) was obtained at STTD Ca:STTD P ratios of 1.39:1, 1.25:1, and 1.66:1, respectively, when STTD P was provided at the requirement(0.33%). If dietary STTD P was below the requirement, increasing dietary Ca resulted in reduced(P < 0.05) ADG and G:F. However, if dietary STTD P was above the requirement, negative effects(P < 0.05) on ADG and G:F of increasing STTD Ca were observed only if dietary STTD Ca exceeded 0.6%. Plasma Ca concentration was positively affected by STTD Ca over the range studied(quadratic, P < 0.01) and negatively affected by increasing STTD P(linear, P < 0.01). There was a linear negative effect(P < 0.05) of STTD Ca on the abundance of S100 G, TRPV6, OCLN, and ZO1 in duodenum, and CLDN and ZO1 in ileum.Conclusions: The STTD Ca:STTD P ratio needed to maximize growth performance of 11-to 25-kg pigs is less than1.40:1, if P is at the estimated requirement. Increasing dietary Ca reduces transcellular absorption of Ca and increases paracellular absorption of Ca.展开更多
Hydroxyapatite (Ca10(PO4)6(OH)2) is widely used as bio-ceramic materials and as adsorbents for separation of bio-molecules. These materials have also been used as adsorbents for heavy metals, supports and as catalysts...Hydroxyapatite (Ca10(PO4)6(OH)2) is widely used as bio-ceramic materials and as adsorbents for separation of bio-molecules. These materials have also been used as adsorbents for heavy metals, supports and as catalysts in oxidation and dehydrogenation reactions. The catalytic performance of these materials depend on the lattice substitution of Ca sites in Hydroxyapatite structure by varied cations as Na, Mg, Sr and Mn, which result in changes in various structural pro perties as crystallinity and morphology. Pure calcium hydroxyapatite (S1) and Cr loaded hydroxyl apatite (S2, S3, S4 and S5) of different chromium concentrations have been prepared by wet precipitated method. An in-vitro examination is essential to investigate the mechanism of the deficient HA and tissue interface reaction by preparing SBF (Simulated Body Fluid) through the elemental and chemical analysis of Ca, P and Cr. FTIR used to analyze the samples after incubation in SBF for 24 day. PH of the samples also was measured at the first period of immersion time. At high loading of chromium ions, the formation of carbonate apatite decrease. The concentrations of the chromium in the Cr_HA crystal during the soaking in SBF are very safe dose for human.展开更多
Objective To study the relationship between micronutrient supplementation and children growth. Methods A double-blind, placebo-controlled trial was conducted in 156 growth retarded preschool children. They were rand...Objective To study the relationship between micronutrient supplementation and children growth. Methods A double-blind, placebo-controlled trial was conducted in 156 growth retarded preschool children. They were randomly assigned to five groups: supplemental control (S-control, n=28), zinc supplementation(+Zn, 3.5mg Zn/day, n=34), zinc and calcium supplementation (+ZnCa, 3.5mg Zn+250mg Ca/day, n=37), zinc and calcium and vitamin A supplementation (+ZnCaVA, 3.5mgZn +250mgCa+200gVA/day, n=28), Calcium and vitamin A supplementation (+CaVA, 250mgCa + 200gVA/day, n=29). Another 34 children with normal height were selected as normal control (N-control). Supplementation continued for twelve months. Results The height gain in +Zn group (7.84cm per year) and +ZnCa group (7.70 cm per year) was significantly higher than that in S-control group (6.74 cm per year, P<0.05); The weight gain in +ZnCaVA group (2.55kg per year) and +CaVA group (2.57 kg per year) was also significantly higher than that in S-control group (2.19kg per year, P<0.05); The average days of illness in each supplementation group were lower than that in S-control (13 days per year compared with 23 days per year). No significant difference was observed on bone age. Conclusion Zinc and Zinc+Calcium supplementation can improve the height gain, and vitamin A can improve weight gain in growth retarded preschool children, but do not affect the maturity of bone. Micronutrient supplementation can lower the morbidity of these children.展开更多
Calcium carbonate with three-dimensional chrysanthemun flower-like structure was successfully prepared from calcium chloride and sodium carbonate ethanol/water mixed solution by a simple precipitation method,using tri...Calcium carbonate with three-dimensional chrysanthemun flower-like structure was successfully prepared from calcium chloride and sodium carbonate ethanol/water mixed solution by a simple precipitation method,using trisodium citrate as crystal modifier.The experimental results show that the three-dimensional structure of chrysanthemun flower-like calcium carbonate is built up with several symmetrical micrometer multi-layer petals arranged around the multi-layer pancake-liked center,and the micrometer center and petals are assemblied by a large number of nanometer spherical particles with size 10-20 nm.It is found that the amount of trisodium citrate,the ethanol volume content has an important influence on the formation of this morphology.A possible mechanism is proposed to explain the formation of three-dimensional chrysanthemun flower-like calcium carbonate according the results.Scanning electron microscopy(SEM),X-ray powder diffraction(XRD),flourier transform infrared spectroscopy(FT-IR),thermogravimety analysis(TG),transmission electron microscopy(TEM) equipped with energy-dispersive X-ray(EDX),and selected area electron diffraction(SAED) were used to characterize the crystals.展开更多
The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of...The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture, it is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Economic conditions in modern agriculture demand high crop yields in order to be profitable and consequently meet the high demand for food that comes with population growth. Oil crop production can be improved by development of new high yielding varieties, and the application of appropriate agronomic practices. There is limited information about the most suitable management practice for application of N, P, K, Zn, Ca and PGRs in order to optimize the quantity and quality of oil and protein of cottonseed. In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, field experiments were conducted to investigate the effect of nitrogen, phosphorus, potassium, foliar application of zinc and calcium, the use of plant growth retardants (Pix, Cycocel or Alar), on cottonseed, protein, oil yields, and oil properties of Egyptian cotton. From the findings of this study, it seems rational to recommend that application of N, P, K, foliar application of Zn and Ca, the use of PGRs (Pix, Cycocel or Alar), could bring about better impact on cottonseed yield, seed protein content, oil and protein yields, oil refractive index, unsaponifiable matter, and unsaturated fatty acids in comparison with the ordinary cultural practices adopted by Egyptian cotton producers.展开更多
Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailin...Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC);2-chloroethyl trimethyl ammonium chloride (CC);or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.展开更多
In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the ...In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the intracellular Ins(1,4,5)P3 concentration at the apical region of pollen tube, the caged Ins(1,4,5)P3 loaded by osmotic shock was activated by 10 s 360 nm UV flash at this domain (10 μm from the tip). More than 70% pollen tubes were induced swelling at apex and/or growth axis reorientation, accompanying temporarily growth arrest, by localized increase of Ins(1,4,5)P3 concentration (n=21). While, pollen tubes without being loaded with caged Ins(1,4,5)P3 had not response to the same dosage UV flash. With FM 1-43 fluorescent staining, it was found that growth perturbation by UV activated caged Ins(1,4,5)P3 had tight link with membrane trafficking at the apical zone of pollen tubes. Upon UV pulse, the apical V-shaped bright area where was full of secretory vesicles spread to a much broader region, which implied that actin filaments at the apical region were remodeled. It was also observed that the FM 1-43 fluorescence intensity at tip remarkably increased than that before UV flash, which demonstrated that more secretory vesicles were accumulated at this region. To estimate the role of Ins(1,4,5)P3 in modulating intracellular calcium concentration and distribution, dextran conjugated fluorescent dye Calcium Green-1 and Rhodamine B were microinjected into pollen tubes together with caged Ins(1,4,5)P3. The results showed that calcium concentration at the subapical region increased upon UV released Ins(1,4,5)P3. Consequently, the tip-focused calcium gradient under the apical dome of pollen tube was disturbed. Simultaneously, the pollen tube bulged at the apical region and its growth rate decreased. As the tip-focused calcium gradient was reestablished, the pollen tube morphology and growth recovered to the normal level. Therefore, Ins(1,4,5)P3 can modulate pollen tube growth rate and direction through mobilizing intracellular calcium and regulating vesicle trafficking during pollen tube finding its way to the ovary.展开更多
The reaction studied in this work is the synthesis of nanometric size calcium carbonate by carbonation of a suspension of lime, which represents the most common industrial route. The carbonation was proceeded in a pil...The reaction studied in this work is the synthesis of nanometric size calcium carbonate by carbonation of a suspension of lime, which represents the most common industrial route. The carbonation was proceeded in a pilot batch reactor. This article presents a method for the determination of nucleation and crystal growth rates of calcium carbonate by following two macroscopic parameters: the mass production rate by precipitation and the specific surface area. The results give a constant nucleation rate around 4 × 1015m-3 ·s-1 and a decreasing crystal growth rate between 0.2 and 2 × 10-10 m·s-1. It also provides the main characteristics of the monoparticle size distributions (i.e. the mean particle sizes and in situ coefficient of variation) in the agglomerates, which cannot be obtained by other known methods. For the carbonation carried out in this work, the mean mass particle size at the end of the reaction is about 300 nm and the coefficient of variation of 0.28 indicates a narrow particle size distribution of the monoparticles.展开更多
Incorporation of trace elements into calcium phosphate structure is of great interest for the development of artificial bone implants. Biphasic calcium phosphate (BCP) composed of hydroxyapatite (HA) and β-tricalcium...Incorporation of trace elements into calcium phosphate structure is of great interest for the development of artificial bone implants. Biphasic calcium phosphate (BCP) composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have been synthesized in the presence of magnesium (5 M% - 20 M%) by gel method under physiological conditions. Crystallization of Mg-BCP in the gel medium mimics the Mg intake in the human body. Powder X-ray dif- fraction and Fourier transform infrared analyses confirmed that the Mg doping leads to the enrichment of β-TCP phase and suppresses the HA content in BCP. Nanoindentation studies indicate a significant decrease in hardness and elastic modulus values of BCP due to Mg doping. In vitro bioactivity study has confirmed the formation of apatite layer on the Mg doped samples making it suitable for bone replacement. The results suggest that the optimum Mg doping promotes the bioactivity which is perquisite for biomedical applications.展开更多
1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate ...1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate is known as a major展开更多
The effects of epidermal growth factor (EGF) on proliferation of G15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells w...The effects of epidermal growth factor (EGF) on proliferation of G15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells were treated with EGF at different concentrations, cell count method was used to determine the proliferation of glioma cells, cell cycle and apoptosis were analyzed by flow cytometry (FCM), and laser scan confocal microscope (LSCM) was used to measure the cytoplasmic free calcium. The results showed that GFAP was diffusedly expressed in GLI5 cells and EGFR was over-expressed. EGF at doses of ≤ 1 ng/mL could significantly stimulate cell proliferation, cells in phase G0/G1 decreased, and those in phase S increased. EGF at doses of 10 and 100ng/ml could inhibit the cell proliferation significantly, and the apoptosis ratio in high dose of EGF group was higher than in control group. EGF could significantly induce a quick rise of intracellular free calcium, but the peak value of intracellular free calcium activated by high dose of EGF was higher than by low dose of EGF. It was suggested that EGF had a dual effect on gliomas: low dose of EGF could stimulate the cell proliferation of gliomas, but high dose of EGF could induce the cell apoptosis and inhibit the proliferation of gliomas, which might be contributed to the difference of intracellular free calcium.展开更多
1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also inc...1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also increase the scaling of vacuum evaporation tanks and brine reusing pipes.Additives have certain impacts on the crystallization dynamics(Randolph et al.,1971).The crystallization展开更多
基金Financial support for this research from AB Vista,Marlborough,UK
文摘Background: A 21-day experiment was conducted to test the hypothesis that Ca requirements to maximize growth performance expressed as the standardized total tract digestible(STTD) Ca to STTD P ratio is less than 1.40:1. The second hypothesis was that increasing dietary Ca increases plasma Ca concentration and downregulates abundance of genes related to Ca absorption(TRPV6, S100 G, and ATP2 B1) in the duodenum, and tight junction proteins(OCLN, CLDN1, and ZO1) in the duodenum and ileum.Methods: Twenty corn-soybean meal diets were formulated using a 4 × 5 factorial design with diets containing 0.16%, 0.33%, 0.42%, or 0.50% STTD P, and 0.14%, 0.29%, 0.44%, 0.59%, or 0.74% STTD Ca. Six hundred and forty pigs(initial weight: 11.1 ± 1.4 kg) were allotted to 20 diets and 5 blocks in a randomized complete block design. On day21, weights of pigs and feed left in feeders were recorded and blood, duodenal tissue, ileal mucosa, and the right femur were collected from 1 pig per pen. Abundance of m RNA was determined in duodenal and ileal tissue via quantitative RT-PCR. Data were analyzed using a response surface model.Results: The predicted maximum ADG(614 g), G:F(0.65), and bone ash(11.68 g) was obtained at STTD Ca:STTD P ratios of 1.39:1, 1.25:1, and 1.66:1, respectively, when STTD P was provided at the requirement(0.33%). If dietary STTD P was below the requirement, increasing dietary Ca resulted in reduced(P < 0.05) ADG and G:F. However, if dietary STTD P was above the requirement, negative effects(P < 0.05) on ADG and G:F of increasing STTD Ca were observed only if dietary STTD Ca exceeded 0.6%. Plasma Ca concentration was positively affected by STTD Ca over the range studied(quadratic, P < 0.01) and negatively affected by increasing STTD P(linear, P < 0.01). There was a linear negative effect(P < 0.05) of STTD Ca on the abundance of S100 G, TRPV6, OCLN, and ZO1 in duodenum, and CLDN and ZO1 in ileum.Conclusions: The STTD Ca:STTD P ratio needed to maximize growth performance of 11-to 25-kg pigs is less than1.40:1, if P is at the estimated requirement. Increasing dietary Ca reduces transcellular absorption of Ca and increases paracellular absorption of Ca.
文摘Hydroxyapatite (Ca10(PO4)6(OH)2) is widely used as bio-ceramic materials and as adsorbents for separation of bio-molecules. These materials have also been used as adsorbents for heavy metals, supports and as catalysts in oxidation and dehydrogenation reactions. The catalytic performance of these materials depend on the lattice substitution of Ca sites in Hydroxyapatite structure by varied cations as Na, Mg, Sr and Mn, which result in changes in various structural pro perties as crystallinity and morphology. Pure calcium hydroxyapatite (S1) and Cr loaded hydroxyl apatite (S2, S3, S4 and S5) of different chromium concentrations have been prepared by wet precipitated method. An in-vitro examination is essential to investigate the mechanism of the deficient HA and tissue interface reaction by preparing SBF (Simulated Body Fluid) through the elemental and chemical analysis of Ca, P and Cr. FTIR used to analyze the samples after incubation in SBF for 24 day. PH of the samples also was measured at the first period of immersion time. At high loading of chromium ions, the formation of carbonate apatite decrease. The concentrations of the chromium in the Cr_HA crystal during the soaking in SBF are very safe dose for human.
文摘Objective To study the relationship between micronutrient supplementation and children growth. Methods A double-blind, placebo-controlled trial was conducted in 156 growth retarded preschool children. They were randomly assigned to five groups: supplemental control (S-control, n=28), zinc supplementation(+Zn, 3.5mg Zn/day, n=34), zinc and calcium supplementation (+ZnCa, 3.5mg Zn+250mg Ca/day, n=37), zinc and calcium and vitamin A supplementation (+ZnCaVA, 3.5mgZn +250mgCa+200gVA/day, n=28), Calcium and vitamin A supplementation (+CaVA, 250mgCa + 200gVA/day, n=29). Another 34 children with normal height were selected as normal control (N-control). Supplementation continued for twelve months. Results The height gain in +Zn group (7.84cm per year) and +ZnCa group (7.70 cm per year) was significantly higher than that in S-control group (6.74 cm per year, P<0.05); The weight gain in +ZnCaVA group (2.55kg per year) and +CaVA group (2.57 kg per year) was also significantly higher than that in S-control group (2.19kg per year, P<0.05); The average days of illness in each supplementation group were lower than that in S-control (13 days per year compared with 23 days per year). No significant difference was observed on bone age. Conclusion Zinc and Zinc+Calcium supplementation can improve the height gain, and vitamin A can improve weight gain in growth retarded preschool children, but do not affect the maturity of bone. Micronutrient supplementation can lower the morbidity of these children.
基金Funded by the National Natural Science Foundation of China (No.21076131)the Foundation of Educational Commission of Hubei Province,China(No.D20122904)
文摘Calcium carbonate with three-dimensional chrysanthemun flower-like structure was successfully prepared from calcium chloride and sodium carbonate ethanol/water mixed solution by a simple precipitation method,using trisodium citrate as crystal modifier.The experimental results show that the three-dimensional structure of chrysanthemun flower-like calcium carbonate is built up with several symmetrical micrometer multi-layer petals arranged around the multi-layer pancake-liked center,and the micrometer center and petals are assemblied by a large number of nanometer spherical particles with size 10-20 nm.It is found that the amount of trisodium citrate,the ethanol volume content has an important influence on the formation of this morphology.A possible mechanism is proposed to explain the formation of three-dimensional chrysanthemun flower-like calcium carbonate according the results.Scanning electron microscopy(SEM),X-ray powder diffraction(XRD),flourier transform infrared spectroscopy(FT-IR),thermogravimety analysis(TG),transmission electron microscopy(TEM) equipped with energy-dispersive X-ray(EDX),and selected area electron diffraction(SAED) were used to characterize the crystals.
文摘The increase in the population in Egypt makes it imperative to explore promising approaches to increase food supply, including protein and oil, to meet the needs of the Egyptian people. Cotton is the principal crop of Egyptian agriculture, it is grown mainly for its fiber, but cottonseed products are also of economic importance. Cottonseed is presently the main source of edible oil and meal for livestock in Egypt. Economic conditions in modern agriculture demand high crop yields in order to be profitable and consequently meet the high demand for food that comes with population growth. Oil crop production can be improved by development of new high yielding varieties, and the application of appropriate agronomic practices. There is limited information about the most suitable management practice for application of N, P, K, Zn, Ca and PGRs in order to optimize the quantity and quality of oil and protein of cottonseed. In maximizing the quantity and quality of a crop’s nutritional value in terms of fatty acids and protein, field experiments were conducted to investigate the effect of nitrogen, phosphorus, potassium, foliar application of zinc and calcium, the use of plant growth retardants (Pix, Cycocel or Alar), on cottonseed, protein, oil yields, and oil properties of Egyptian cotton. From the findings of this study, it seems rational to recommend that application of N, P, K, foliar application of Zn and Ca, the use of PGRs (Pix, Cycocel or Alar), could bring about better impact on cottonseed yield, seed protein content, oil and protein yields, oil refractive index, unsaponifiable matter, and unsaturated fatty acids in comparison with the ordinary cultural practices adopted by Egyptian cotton producers.
文摘Seed quality is one of the most important factors for stand establishment in cotton (Gossypium Sp.), and the use of good-quality seeds is therefore essential to obtain an optimum plant population. Conditions prevailing during seed formation can affect the quality of seed produced, and hence crop establishment in the next growing season. These conditions can affect the germination of the seeds and the ability of the seedlings to emerge from soil. Field experiments were conducted to investigate the effect of nitrogen (N), phosphorus (P), potassium (K), foliar application of zinc (Zn) and calcium (Ca), and the use of plant growth retardants (PGR) [e.g., 1, 1-dimethyl piperidinium chloride (MC);2-chloroethyl trimethyl ammonium chloride (CC);or succinic acid 2, 2-dimethyl hydrazide (SADH)], during square initiation and boll setting stage, on growth, seed yield, seed viability, and seedling vigor of Egyptian cotton (G. barbadense). Dry matter yield, total chlorophyll concentration, K, Zn and P-uptake plant-1, were increased with the addition of K, foliar application of Zn, and different concentrations of P (576-1728 g·ha-1 of P). Seed yield plant-1 and plot-1, seed weight, seed viability, seedling vigor, and cool germination test performance increased as a result of the addition of the high N-rate (142.8 kg·ha-1 N), the high P-rate (74 kg·ha-1 P2O5), K (47 kg·ha-1 K), and from application of Zn, and Ca and the PGR. From the findings of the present study, band application of such treatments showed improved cotton-seed yield and affected the quality of seed produced, and hence crop establishment in the next growing season.
文摘In this article, the functions of D-myo-inositol-1,4,5-trisphosphate (Ins [1,4,5] P3) in regulating pollen tube polar growth were investigated by application of caged version of the phosphoinositides. To increase the intracellular Ins(1,4,5)P3 concentration at the apical region of pollen tube, the caged Ins(1,4,5)P3 loaded by osmotic shock was activated by 10 s 360 nm UV flash at this domain (10 μm from the tip). More than 70% pollen tubes were induced swelling at apex and/or growth axis reorientation, accompanying temporarily growth arrest, by localized increase of Ins(1,4,5)P3 concentration (n=21). While, pollen tubes without being loaded with caged Ins(1,4,5)P3 had not response to the same dosage UV flash. With FM 1-43 fluorescent staining, it was found that growth perturbation by UV activated caged Ins(1,4,5)P3 had tight link with membrane trafficking at the apical zone of pollen tubes. Upon UV pulse, the apical V-shaped bright area where was full of secretory vesicles spread to a much broader region, which implied that actin filaments at the apical region were remodeled. It was also observed that the FM 1-43 fluorescence intensity at tip remarkably increased than that before UV flash, which demonstrated that more secretory vesicles were accumulated at this region. To estimate the role of Ins(1,4,5)P3 in modulating intracellular calcium concentration and distribution, dextran conjugated fluorescent dye Calcium Green-1 and Rhodamine B were microinjected into pollen tubes together with caged Ins(1,4,5)P3. The results showed that calcium concentration at the subapical region increased upon UV released Ins(1,4,5)P3. Consequently, the tip-focused calcium gradient under the apical dome of pollen tube was disturbed. Simultaneously, the pollen tube bulged at the apical region and its growth rate decreased. As the tip-focused calcium gradient was reestablished, the pollen tube morphology and growth recovered to the normal level. Therefore, Ins(1,4,5)P3 can modulate pollen tube growth rate and direction through mobilizing intracellular calcium and regulating vesicle trafficking during pollen tube finding its way to the ovary.
文摘The reaction studied in this work is the synthesis of nanometric size calcium carbonate by carbonation of a suspension of lime, which represents the most common industrial route. The carbonation was proceeded in a pilot batch reactor. This article presents a method for the determination of nucleation and crystal growth rates of calcium carbonate by following two macroscopic parameters: the mass production rate by precipitation and the specific surface area. The results give a constant nucleation rate around 4 × 1015m-3 ·s-1 and a decreasing crystal growth rate between 0.2 and 2 × 10-10 m·s-1. It also provides the main characteristics of the monoparticle size distributions (i.e. the mean particle sizes and in situ coefficient of variation) in the agglomerates, which cannot be obtained by other known methods. For the carbonation carried out in this work, the mean mass particle size at the end of the reaction is about 300 nm and the coefficient of variation of 0.28 indicates a narrow particle size distribution of the monoparticles.
文摘Incorporation of trace elements into calcium phosphate structure is of great interest for the development of artificial bone implants. Biphasic calcium phosphate (BCP) composed of hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) have been synthesized in the presence of magnesium (5 M% - 20 M%) by gel method under physiological conditions. Crystallization of Mg-BCP in the gel medium mimics the Mg intake in the human body. Powder X-ray dif- fraction and Fourier transform infrared analyses confirmed that the Mg doping leads to the enrichment of β-TCP phase and suppresses the HA content in BCP. Nanoindentation studies indicate a significant decrease in hardness and elastic modulus values of BCP due to Mg doping. In vitro bioactivity study has confirmed the formation of apatite layer on the Mg doped samples making it suitable for bone replacement. The results suggest that the optimum Mg doping promotes the bioactivity which is perquisite for biomedical applications.
基金financial support of National Nature Science Foundation (21376178)TIDA giant growth plan (2011-XJR13020)+3 种基金Tianjin Science and technology support program (12ZCDZSF06900)Tianjin University of Science and Technology fund for scientific research (20120119)Tianjin education commission program (20130509)Research fund for the doctoral program of higher education of China(20131208120001)
文摘1 Introduction Calcium sulfate deposition is one of the most important and serious problems faced by heat transfer equipment during operation(Pavlos et al.,1999;Liu et al.,1996).The crystallization of calcium sulfate is known as a major
文摘The effects of epidermal growth factor (EGF) on proliferation of G15 glioma cells and the possible mechanisms were investigated. GFAP and EGFR expression was detected by immunohistochemical method. After the cells were treated with EGF at different concentrations, cell count method was used to determine the proliferation of glioma cells, cell cycle and apoptosis were analyzed by flow cytometry (FCM), and laser scan confocal microscope (LSCM) was used to measure the cytoplasmic free calcium. The results showed that GFAP was diffusedly expressed in GLI5 cells and EGFR was over-expressed. EGF at doses of ≤ 1 ng/mL could significantly stimulate cell proliferation, cells in phase G0/G1 decreased, and those in phase S increased. EGF at doses of 10 and 100ng/ml could inhibit the cell proliferation significantly, and the apoptosis ratio in high dose of EGF group was higher than in control group. EGF could significantly induce a quick rise of intracellular free calcium, but the peak value of intracellular free calcium activated by high dose of EGF was higher than by low dose of EGF. It was suggested that EGF had a dual effect on gliomas: low dose of EGF could stimulate the cell proliferation of gliomas, but high dose of EGF could induce the cell apoptosis and inhibit the proliferation of gliomas, which might be contributed to the difference of intracellular free calcium.
基金financial support of National Nature Science Foundation (21376178)TIDA giant growth plan (2011-XJR13020)+3 种基金Tianjin Science and technology support program (12ZCDZSF06900)Tianjin University of Science and Technology fund for scientific research (20120119)Tianjin education commission program (20130509)Research fund for the doctoral program of higher education of China (20131208120001)
文摘1 Introduction There exist calcium and sulfate ions outside sodium chloride in solution mining for calcium sulfate brine.The calcium and sulfate ions not only affect the purity of the vacuum salt products,but also increase the scaling of vacuum evaporation tanks and brine reusing pipes.Additives have certain impacts on the crystallization dynamics(Randolph et al.,1971).The crystallization