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1.
We examined the temperature-dependent development, adult longevity, fertility, and sex ratio of the whitefly Aleurocanthus camelliae, which infests tea plants, under laboratory conditions. Eggs and nymphs were reared on tea shoots at 20, 22.5, 25, and 27.5 °C with a photoperiod of 15L:9D. The developmental zero of the egg, total nymphal stadia, and egg–adult duration of A. camelliae were 12.6, 11.6, and 11.9 °C, respectively, with thermal constants of 176.7, 394.7, and 569.9 d-degrees, respectively. The mean longevities of adult female and male A. camelliae were 4.4 and 2.7 d, respectively. These results suggested A. camelliae voltinism of two to three generations per year in Kanto, Tokai, and Kinki districts and three to five generations per year in the Shikoku and Kyushu districts, Japan.  相似文献   

2.
Background aimsMesenchymal stromal cells (MSC) have recently been identified as a therapeutic option in several clinical conditions. Whereas bone marrow (BM) is considered the main source of MSC (BM-MSC), the invasive technique required for collection and the decline in allogeneic donations call for alternative sources. Human umbilical cord (UC) represents an easily available source of MSC (UC-MSC).MethodsSections of full-term UC were transferred to cell culture flasks and cultured in 5% human platelet lysate (PL)-enriched medium. Neither enzymatic digestion nor blood vessel removal was performed. After 2 weeks, the adherent cells were harvested (P1), replated at low density and expanded for two consecutive rounds (P2 and P3).ResultsWe isolated and expanded MSC from 9/9 UC. UC-MSC expanded with a mean fold increase (FI) of 42 735 ± 16 195 from P1 to P3 in a mean of 29 ± 2 days. By processing the entire cord unit, we theoretically could have reached a median of 9.5 × 1010 cells (ranging from 1.0 × 1010 to 29.0 × 1010). UC-MSC expressed standard surface markers; they contained more colony-forming unit (CFU)-fibroblast (F) and seemed less committed towards osteogenic, chondrogenic and adipogenic lineages than BM-MSC. They showed immunosuppressive properties both in vitro and in an in vivo chronic Graft versus Host disease (cGvHD) mouse model. Both array-Comparative Genomic Hybridization (CGH) analysis and karyotyping revealed no chromosome alterations at the end of the expansion. Animal studies revealed no tumorigenicity in vivo.ConclusionsUC constitute a convenient and very rich source of MSC for the production of third-party ‘clinical doses’ of cells under good manufacturing practice (GMP) conditions.  相似文献   

3.
DNA from porcine circovirus type 1 (PCV1) and 2 (PCV2) has recently been detected in two vaccines against rotaviral gastroenteritis from manufacturers A and B. We investigated if PCV1 sequences are present in other viral vaccines. We screened seeds, bulks and final vaccine preparations from ten manufacturers using qRT-PCR. We detected 3.8 × 103 to 1.9 × 107 PCV1 DNA copies/milliliter in live poliovirus seeds for inactivated polio vaccine (IPV) from manufacturer A, however, following inactivation and purification, the finished IPV was PCV1-negative. PCV1 DNA was not detectable in live polio preparations from other vaccine producers. There was no detectable PCV1 DNA in the measles, mumps, rubella and influenza vaccines analysed including material supplied by manufacturer A. We confirmed that the PCV1 genome in the rotavirus vaccine from manufacturer A is near full-length. It contains two mutations in the PCV cap gene, which may result from viral adaptation to Vero cells. Bulks of this vaccine contained 9.8 × 1010 to 1.8 × 1011 PCV1 DNA copies/millilitre and between 4.1 × 107 and 5.5 × 108 DNA copies were in the final doses. We found traces of PCV1 and PCV2 DNA in the rotavirus vaccine from manufacturer B. This highlights the issue of vaccine contamination and may impact on vaccine quality control.  相似文献   

4.
Xu L J  Wang B  Yu Z  Sun Q Z 《农业工程》2009,29(3):166-170
Without a robust and healthy root system, establishment, productivity, and persistence are compromised. Consequently, research on alfalfa root morphology and health is very important in development of technology for efficient improvement and production of alfalfa. The objectives of this study were to evaluate the root morphology and health of three alfalfa varieties, Algonquin, Golden Queen, and Yellow Flower and to determine relationships among root morphology traits and root health. Yields from these varieties ranged from 5.83 to 43.93 t/ha, total root length ranged from 215.17 to 708.89 mm, root surface area from 124.95 to 468.37 cm2, volume from 3.24 to 57.72 cm3, and forks from 1.25 × 103 to 10.54 × 103, and tips from 0.65 × 103 to 3.17 × 103. Root infestation score was negatively correlated with yield (r = ?0.997, P < 0.01), and was positively correlated with all root morphology traits (r = 0.466–0.997, P < 0.01), and yield was negatively associated with root morphology traits (r = ?0.755 to ?0.998, p < 0.01) with the exception of root tips (r = 0.448, P < 0.01). Results from these analyses indicated that root infestation score was the lowest averaged over age of alfalfa stand in Algonquin. Yield in 2-year old stands was greater in Golden Queen compared to the other two cultivars.  相似文献   

5.
An electro-transformation procedure was established for Bacillus cereus ATCC 14579. Using early growth-stage culture and high electric field, the ectroporation efficiency was up to 2 × 109 cfu μg 1 ml 1 with pC194 plasmid DNA. The procedure was tested with three other plasmids, of various sizes, replication mechanisms and selection markers, and the transformation efficiencies ranged between 2 × 106 and 1 × 108 cfu μg 1 ml 1. The effects of two wall-weakening agents on electroporation rates were also evaluated. The transformation rate that was reached with our procedure is 103 times higher than that previously obtained with members of the Bacillus genus with similar plasmids, and 106 times superior than that achieved with available protocols for B. cereus. The proposed method is quick, simple, efficient with small rolling circle plasmids and large theta replicating plasmids with low copy number per cell, and suitable for many genetic manipulations that are not possible without high-efficiency transformation protocols.  相似文献   

6.
The present study investigates the interaction of the second generation photosensitizer Foscan® with plasma albumin and lipoproteins. Spectroscopic studies indicated the presence of monomeric and aggregated Foscan® species upon addition to plasma protein solutions. Kinetics of Foscan® disaggregation in albumin-enriched solutions were very sensitive to the protein concentration and incubation temperature. Kinetic analysis demonstrated that two types of Foscan® aggregated species could be involved in disaggregation: dimers with a rate constant of k1 = (2.30 ± 0.15) × 10−3 s−1 and higher aggregates with rate constants varying from (0.55 ± 0.04) × 10−3 s−1 for the lowest to the (0.17 ± 0.02) × 10−3 s−1 for the highest albumin concentration. Disaggregation considerably increased with the temperature rise from 15 °C to 37 °C. Compared to albumin, Foscan® disaggregation kinetics in the presence of lipoproteins displayed poorer dependency on lipoprotein concentrations and smaller variations in disaggregation rate constants. Gel-filtration chromatography analysis of Foscan® in albumin solutions demonstrated the presence of aggregated fraction of free, non-bound to protein Foscan® and monomeric Foscan®, bound to protein.  相似文献   

7.
Options for control of northern root-knot nematode (NRKN, Meloidogyne hapla) on vegetables are very limited currently. In this study, we characterized the parasitism of Myrothecium verrucaria strain X-16, a new nematophagous fungus, on NRKN at the stages of eggs, J2, and adult females and evaluated its biocontrol efficacy in the greenhouse. Strain X-16 produced conidia that geminated and invaded in 80 h after in contact with eggs, causing the shrinkage and depression of egg shell and blastocolysis of the embryo. The strain also attacked 2nd-stage juveniles by producing developing surface networks of hyphae on the nematode body wall. Strain X-16 attacked adult females by producing dense networks of hyphae on the nematode body wall in 120 h. Strain X-16 had lethal effects (22–71% mortality) against NRKN J2 at the concentration as low as 3.1 × 107 conidia/ml and with the incubation treatment time as short as 24 h. The lethal effects linearly increased with the increase of conidial concentration, with the estimated LC50 values as low as 1.0 × 108 conidia/ml. Soil treatments with strain X-16 at 1%, 2% or 4% (wt/wt) induced significant reductions in J2 nematode counts in 100 g of dry soil, Pf/Pi ratios and root-know index in cucumber in the greenhouse evaluations. These studies are the first to demonstrate that M. verrucaria is able to parasitize NRKN and strain X-16 can be a potential biocontrol agent for management of NRKN.  相似文献   

8.
Conidiobolus thromboides is an entomophthoralean fungus with potential as a biological control agent of aphids. However, its application in biological control is limited due to its formulation requirements. The objective of this study was to develop and optimise a novel air-extrusion method to embed C. thromboides hyphae at high density in alginate pellets. An orthogonal experimental design was used to investigate selected combinations of parameters known to affect hyphal density within pellets. The diameter of pellets produced, and the calculated density of hyphae within them, ranged from 0.18 ± 0.09 to 3.17 ± 0.06 mm and from 0.02 to 350.56 mg/mm3 respectively. These data were used to predict the optimal parameter combination to deliver the greatest density of hyphae of C. thromboides per pellet: 1% sodium alginate, a 1:2 ratio of hyphae to sodium alginate, an orifice diameter of 0.232 mm and an air pressure of 0.05 MPa. Pellets made under the optimal conditions predicted produced a mean total of 4.3 ± 0.6 × 105 conidia per pellet at 100% relative humidity which was significantly greater than the mean total number of conidia produced from infected aphid cadavers of comparable size (9.35 ± 0.85 × 104) (p < 0.001). In conclusion, air-extrusion embedding appears to be a promising method for formulating in vitro-produced hyphae of C. thromboides for use in biological control.  相似文献   

9.
The aim of this study was to determine the effects of antioxidants such as reduced glutathione (GSH) and cysteine in Laiciphose® extender on semen parameters, fertilizing ability, lipid peroxidation (LPO) level and glutathione peroxidise (GPx) activity of post-thawed bull semen. Totally 54 ejaculates of three bulls were used in the study. Five groups, namely; GSH (0.5 and 2 mM), cysteine (5 and 10 mM) and control group, were conducted to test the antioxidants in Laiciphose®. Insemination doses were processed that each 0.25-mL straw contained 15 × 106 sperm. The addition of antioxidants did not present any significant effect on the percentages of post-thaw sperm morphology (acrosome and total abnormalities), subjective, CASA and progressive motilities, as well as sperm motility characteristics (VAP, VSL, VCL, LIN and ALH), compared to the control groups (P > 0.05). GSH 0.5 mM (55.5 ± 7.38%) and cysteine 10 mM (48 ± 5.65%) led to lower rates of DNA damage, compared to control (P < 0.05). As regards to MDA level, cysteine at 10 mM dose gave the highest level (4.99 ± 0.44 nmol/L) (P < 0.001). GPx activity was demonstrated to be higher level upon the addition of 5 mM cysteine when compared to the other groups (P < 0.05). With respect to fertility results based on 60-day non-returns, the supplementation of antioxidants did not present significant differences (P > 0.05). The results of this study may provide an useful information for the future studies in this area. So, further studies could be suggested to achieve better information in terms of the DNA damage and fertilizing capacity of bull sperm frozen with effective antioxidants.  相似文献   

10.
11.
This study aimed to evaluate the effect of commercially used entomopathogens on Africanized Apis mellifera L. (Hymenoptera: Apidae). Four bioassays were performed: 1) pulverized entomopathogens on A. mellifera; 2) entomopathogens sprayed on a smooth surface; 3) entomopathogens sprayed on soy leaves; and 4) entomopathogens mixed with candy paste (sugar syrup). Five treatments were prepared: sterile distilled water (control), distilled water sterilized with Tween® 80 (0.01%), and the commercial entomopathogens Metarhizium anisopliae E9 (1.0 × 109 conidia mL?1), Beauveria bassiana PL63 (1.0 × 108 conidia mL?1) and Bacillus thuringiensis var. kurstaki HD-1 (3.0 × 108 spores mL?1). Each treatment consisted of five repetitions, with 20 workers per repetition, which were stored in a plastic box and, later, in a biological oxygen demand (B.O.D.) incubator (27 ± 2 °C, RH of 60% ± 10%, 12-h photophase). The mortality of the workers was evaluated from 1 h to 240 h, and the data were analyzed using Bayesian inference. The workers killed by the ingestion of candy paste contaminated with the pathogens (products) were randomly separated and selected for the removal of the midgut. Each midgut was fixed in Bouin's solution and prepared for histology. B. bassiana was verified to reduce the survival of A. mellifera workers in all bioassays. Moreover, M. anisopliae reduced the survival of A. mellifera workers directly sprayed, on a smooth surface and mixed with candy. B. thuringiensis reduced A. mellifera survival on a smooth surface and mixed with candy paste. However, its effects were lower than that observed by B. bassiana. The treatments with the biological products did not induce morphometric alterations in the midgut of A. mellifera.  相似文献   

12.
Germination of Aspergillus nidulans conidia in liquid cultures was progressively inhibited at inoculum loads above 1 × 105 conidia mL?1. High conidial densities also inhibited growth of neighbouring mycelia. The eight-carbon oxylipin 1-octen-3-ol was identified as the main inhibitor in a fraction also containing 3-octanone and 3-octanol.These three oxylipins also increased the conidiation rate of dark-grown surface cultures, but had no effect on liquid cultures. 3-octanone was the most conidiogenic compound. The action of 3-octanone required functional forms of developmental activators fluG, flbB-D and brlA, and was not additive to the conidiogenic effect of stress stimuli such as osmotic stress or carbon starvation.Oxylipins were produced shortly after hyphae made contact with the atmosphere and were most effective on aerial mycelia, indicating that they perform their signalling function in the gas phase.  相似文献   

13.
Conidia of Trichoderma harzianum produced from either solid or liquid fermentation must be dried to prevent spoilage by microbial contamination, and to induce dormancy for formulation development and prolonged self-life. Drying conidia of Trichoderma spp. in large scale production remains the major constraint because conidia lose viability during the drying process at elevated temperatures. Moreover, caking must be avoided during drying because heat generated by milling conidial chunks will kill conidia. It is ideal to dry conidia into a flow-able powder for further formulation development. A method was developed for microencapsulation of Trichoderma conidia with sugar through spray drying. Microencapsulation with sugars, such as sucrose, molasses or glycerol, significantly (P < 0.05) increased the survival percentages of conidia after drying. Microencapsulation of conidia with 2% sucrose solution resulted in the highest survival percentage when compared with other sucrose concentrations and had about 7.5 × 1010 cfu in each gram of dried conidia, and 3.4 mg of sucrose added to each gram of dried conidia. The optimal inlet/outlet temperature setting was 60/31 °C for spray drying and microencapsulation. The particle size of microencapsulated conidia balls ranged from 10 to 25 μm. The spray dried biomass of T. harzianum was a flow-able powder with over 99% conidia, which could be used in a variety of formulation developments from seed coatings to sprayable formulations.  相似文献   

14.
Submerged conidia and blastospores of the entomopathogenic fungus Isaria fumosorosea are produced in several liquid culture media. However, yields and the ecological fitness of these propagules vary according to culture media composition. In most culture media, hyphae, blastospores and submerged conidia are white but we found that in some media they develop a brown pigmentation. A dark pigment was extracted from brown-pigmented propagules and analyzed by IR spectroscopy. Adsorption bands coincided to those characteristics of melanins.Hadamard's matrices were employed in order to increase submerged conidia yields and brown pigmentation of fungal propagules. Media containing 20–30 mg/l of FeSO4·7H2O and 6–12 mg/l of CuSO4·5H2O allowed reaching the highest pigmentation (9 in a hedonic scale). A maximal concentration of submerged conidia of 1.0 (±1.2) × 1012 cell/l was achieved after 120 h of liquid culture in a improved culture medium, containing 25 ml/l of Polyethylene glycol (MW 200), substance which enhanced submerged conidia production, reducing free mycelia or mycelial pellets formation. In the improved medium, it was estimated that more than 60% of produced biomass corresponded to submerged conidia and blastospores, while in other media, mycelia were the main product (80–97%).  相似文献   

15.
Background aimsThe ability of hematopoietic progenitor cells–apheresis (HPC-A) that have been stored for many years after cryopreservation to reconstitute hematopoiesis following high-dose chemo/radiotherapy has not been well-documented.MethodsIn this retrospective study, eight Canadian centers contributed data from 53 autologous stem cell transplants (ASCT) performed using HPC-A that had undergone long-term storage (>2 years, range 2–7 years) and 120 ASCT using HPC-A stored for <6 months (short-term storage).ResultsThe doses of nucleated and CD34+ cells per kilogram recipient weight were similar between the short- (mean ± SD, 4.7 ± 4.9 × 108 and 6.8 ± 4.3 × 106, respectively) and long- (4.0 ± 4.9 × 108 and 6.1 ± 3.4 × 106, respectively) term storage groups. The median days to neutrophils (absolute neutrophil count; ANC) >0.5 × 109/L (median 11 days for both short- and long-term storage) and platelets >20 × 109/L (median 12 and 11 for short- and long-term storage, respectively) post-ASCT were not significantly different between the two groups. When ASCT performed with <5 × 106/kg CD34+ cells was compared there was also no difference in ANC or platelet recovery (median 12 days for both after short-term storage, and 12 and 11 days, respectively, after long-term storage). Fourteen HPC-A products stored for >5 years also showed similar count recoveries as the entire long-term storage group (median 11 days for both ANC and platelets).ConclusionsCryopreserved HPC-A can be stored for at least 5 years with no apparent loss in their ability to support hematopoietic reconstitution after high-dose chemotherapy.  相似文献   

16.
Carbon fiber microelectrodes and carbon fiber composite minielectrodes (CFM/CFCM) have been generally used for measurements of nitric oxide (NO) concentration in chemical and biological systems. The response time of a CFM/CFCM is usually from milliseconds to seconds depending on the electrode size, the thickness of coating layers on the electrode, and NO diffusion coefficients of the coating layers. As a result, the time course of recoded current changes (It curves) by the CFM/CFCM may be different from the actual time course of NO concentration changes (ct curves) if the half-life of NO decay is close to or shorter than the response time of the electrode used. This adds complexity to the process for determining rate constants of NO decay kinetics from the recorded current curves (It curves). By computer simulations based on a mathematical model, an approximation method was developed for determining rate constants of NO decay from the recorded current curves. This method was first tested and valuated using a commercial CFCM in several simple reaction systems with known rate constants. The response time of the CFCM was measured as 4.7 ± 0.7 s (n = 5). The determined rate constants of NO volatilization and NO autoxidation in our measurement system at 37 °C are (1.9 ± 0.1) × 10?3 s?1 (n = 4) and (2.0 ± 0.3) × 103 M?1 s?1 (n = 7), which are close to the reported rate constants. The method was then applied to determine the rate of NO decay in blood samples from control and smoking exposed mice. It was observed that the NO decay rate in the smoking group is >20% higher than that in control group, and the increased NO decay rate in the smoking group was reversed by 10 μM diphenyleneiodonium chloride (DPI), an inhibitor of flavin enzymes such as leukocyte NADPH oxidase.  相似文献   

17.
Cai Z P  Huang W W  An M  Duan S S 《农业工程》2009,29(5):297-301
Effects of irradiance and iron on the growth of a typical harmful algal blooms (HABs) causative dinoflagellate, Scrippsiella trochoidea, were investigated under various irradiances (high light: 70 μmol m?2 s?1 and low light: 4 μmol m?2 s?1) and iron concentrations (low iron: 0.063 mg L?1, medium iron: 0.63 mg L?1 and high iron: 6.3 mg L?1), and evaluated by the parameters of algal cell density, specific growth rate, optical density and chlorophyll a content. The results indicated that there was significant difference in the cell density of dinoflagellate S. trochoidea between high light and low light intensity treatments across the entire experiments, 7-fold higher at high irradiance as compared with low irradiance, which was further enhanced by the iron concentration. It was found that the maximum cell density of 25 × 104 cell mL?1 occurred under the combination of high light intensity and high iron concentration, followed by 23 × 104 cell mL?1 in the combination of high light and medium iron, and 20 × 104 cell mL?1 in the combination of high light and low iron. There was no significant effect of iron concentration on the cell density under low light intensity. The cell density maintained about 3 × 104 cell mL?1 across all combinations of iron concentrations and low light in the end of experiments. Such interactive effects of light intensity and iron level dependent were also observed for the specific growth rate, OD680 and chlorophyll a content of S. trochoidea. The maximum values of specific growth rate, OD680 and chlorophyll a content peaked at the condition of high irradiance and high iron, which were 0.22 d?1, 0.282 and 0.673 mg L?1, respectively. In general, their values increased significantly with the increasing of iron concentration at high irradiance, whereas no significant difference was observed among three iron concentrations at low irradiance, all remaining approximately 0.06 d?1, 0.03 and 0.050 mg L?1, respectively. Those results suggest that there may be a strong interactive effect between irradiance and iron on microalgal growth and their physiological characteristics. The combination of high light and high iron concentration may accelerate algal cell growth and pigment biosynthesis, thus leading to massive occurrence of HABs.  相似文献   

18.
All entomopathogenic fungi infect insects by direct penetration through the cuticle rather than per os through the gut. Genetic transformation can confer fungi with per os virulence. However, unless the recipient isolate is nonpathogenic to the target insect, mortality caused by a transgenic isolate cannot be attributed solely to oral virulence due to the potential for some simultaneous cuticular infection. Here, a Metarhizium anisopliae wild-type isolate (MaWT) nonpathogenic to Spodoptera litura was genetically engineered to provide a transformed isolate (MaVipT31) expressing the insect midgut-specific toxin Vip3Aa1. Toxin expression was confirmed in MaVipT31 hyphae and conidia using Western blotting. Mortality, leaf consumption and body weight of S. litura larvae (instars I–IV) exposed to a range of concentrations of MaWT conidia were not significantly different to controls although the number of conidia ingested by surviving larvae during the bioassay ranged from 2.3 × 105 (instar I) to 8.1 × 106 (instar IV). In contrast, consumption of MaVipT31 conidia caused high mortalities, reduced leaf consumption rates and decreased body weights in all instars evaluated, demonstrating that oral virulence had been acquired by MaVipT31. Larval mortalities were much more dependent on the number of MaVipT31 conidia ingested than the duration of time spent feeding on conidia-treated leaves (r2: 0.83–0.94 for instars I–IV). LC50 and LT50 trends for MaVipT31 estimated by time-concentration-mortality modeling analyses differed greatly amongst the instars. For 50% kill to be achieved, instar I larvae required 3, 4 and 5 days feeding on the leaves bearing 103, 28 and 8 conidia/mm2 respectively; instar IV larvae required 6, 7 and 8 days feeding on leaves bearing 1760, 730 and 410 conidia/mm2 respectively. Our results provide a deeper insight into the high oral virulence acquired by an engineered isolate and highlight its great potential for biological control.  相似文献   

19.
Background aimsThe rising use of allogeneic transplantation in older recipients necessitates considering older related donors. The effect of related donor age for peripheral blood stem cell allografts (PBSC) on graft maintenance and outcomes, independent of CD34+cell dose, has not been well-characterized.MethodsHLA-related donors (98% siblings) underwent a uniform filgrastim-based mobilization regimen aiming to collect and infuse 5 × 106 CD34+ cells/recipient kg. Donor and recipient age were modeled in multiple ways to account for the correlation, and outcomes reported by decade of donor age.ResultsThe median donor and recipient ages were 52 years and 54 years, respectively. The mean CD34+ cell dose infused was 5.6 × 106 CD34+/kg and 75% of patients received a narrow range between 4.4 and 6.6 × 106 CD34+ cells/kg. Neither better PBSC mobilization nor higher CD34+ content of allografts was significantly associated with engraftment or transplant outcomes. After adjusting for recipient age and other prognostic factors, older donor age by decade conferred a lower risk of non-relapse mortality (NRM) [hazard ratio (HR) = 0.64, 95% confidence interval (CI) 0.45–0.91, P = 0.013] and borderline improvement in overall survival (OS) (HR = 0.76, 95% CI 0.58–0.99, P = 0.045) without altering progression-free survival (PFS) (HR = 0.85, 95% CI 0.66–1.07, P = 0.18).ConclusionsOlder donor age does not worsen outcome after matched related donor PBSC transplantation in patients receiving a narrow range CD34+ cells. The relatively small sample size mandates that the finding of similar to improved outcomes for older related donor age must be confirmed in larger studies.  相似文献   

20.
A water-insoluble polysaccharide (PCS3-II) extracted from sclerotium of Poria cocos was identified as a linear (1  3)-β-d-glucan by 13C NMR and gas chromatography. Aqueous 0.5 M NaOH/0.2 M urea was a good solvent for PCS3-II and the dependence of intrinsic viscosity ([η]) on weight-average molecular weight (Mw) was established in the Mw range from 7.68 × 104 to 5.14 × 105 to be [η] = 3.39 × 10?2 MW0.62cm3g-1 at 25 °C by using laser light scattering and viscometry. The chain conformation parameters of PCS3-II in the 0.5 M NaOH/0.2 M urea solution was 2.3 (± 0.3) nm for persistence length (q), 580 g mol?1 nm?1 for molar mass per unit contour length (ML), 0.8 (± 0.2) nm for the diameter of the chain (d) and 3.63 for limited characteristic ratio (C). The results revealed, for the first time, that PCS3-II existed as a flexible chain in 0.5 M NaOH/0.2 M urea aqueous solution.  相似文献   

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