Population dynamics with resource-dependent dispersal: single- and two-species models.

In this paper, we consider the population models with resource-dependent dispersal for single-species and two-species with competition. For the single-species model, it is well-known that the total population supported by the environment is always greater than the environmental carrying capacity if the dispersal is simply random diffusion. However, we find that the total population supported can be equal or smaller than the environmental carrying capacity when the dispersal depends on the resource distribution. This analytical finding not only well agrees with the yeast experiment observation of Zhang et al. (Ecol Lett 20(9):1118-1128, 2017), but also indicates that resource-dependent dispersal may produce different outcomes compared to the random dispersal. For the two-species competition model, when two competing species use the same dispersal strategy up to a multiplicative constant (i.e. their dispersal strategies are proportional) or both diffusion coefficients are large, we give a classification of global dynamics. We also show, along with numerical simulations, that if the dispersal strategies are resource-dependent, even one species has slower diffusion, coexistence is possible though competitive exclusion may occur under different conditions. This is distinct from the prominent result that with random dispersal the slower diffuser always wipes out its fast competitor. Our analytical results, supported by the numerical simulations, show that the resource-dependent dispersal strategy has profound impact on the population dynamics and evolutionary processes.

Novel spatial profiles of some diffusive SIS epidemic models.

In this paper, we are concerned with two SIS epidemic reaction-diffusion models with mass action infection mechanism of the form SI, and study the spatial profile of population distribution as the movement rate of the infected individuals is restricted to be small. For the model with a constant total population number, our results show that the susceptible population always converges to a positive constant which is indeed the minimum of the associated risk function, and the infected population either concentrates at the isolated highest-risk points or aggregates only on the highest-risk intervals once the highest-risk locations contain at least one interval. In sharp contrast, for the model with a varying total population number which is caused by the recruitment of the susceptible individuals and death of the infected individuals, our results reveal that the susceptible population converges to a positive function which is non-constant unless the associated risk function is constant, and the infected population may concentrate only at some isolated highest-risk points, or aggregate at least in a neighborhood of the highest-risk locations or occupy the whole habitat, depending on the behavior of the associated risk function and even its smoothness at the highest-risk locations. Numerical simulations are performed to support and complement our theoretical findings.

On the Lotka-Volterra competition system with dynamical resources and density-dependent diffusion.

In this paper, we consider the following Lotka-Volterra competition system with dynamical resources and density-dependent diffusion in a bounded smooth domain [Formula: see text] with homogeneous Neumann boundary conditions, where the parameters [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] ([Formula: see text]) are positive constants, m(x) is the prey's resource, and the dispersal rate function [Formula: see text] satisfies the the following hypothesis: [Formula: see text], [Formula: see text] on [Formula: see text] and [Formula: see text]. When m(x) is constant, we show that the system (*) with has a unique global classical solution when the initial datum is in functional space [Formula: see text] with [Formula: see text]. By constructing appropriate Lyapunov functionals and using LaSalle's invariant principle, we further prove that the solution of (*) converges to the co-existence steady state exponentially or competitive exclusion steady state algebraically as time tends to infinity in different parameter regimes. Our results reveal that once the resource w has temporal dynamics, two competitors may coexist in the case of weak competition regardless of their dispersal rates and initial values no matter whether there is explicit dependence in dispersal or not. When the prey's resource is spatially heterogeneous (i.e. m(x) is non-constant), we use numerical simulations to demonstrate that the striking phenomenon "slower diffuser always prevails" (cf. Dockery et al. in J Math Biol 37(1):61-83, 1998; Lou in J Differ Equ 223(2):400-426, 2006) fails to appear if the non-random dispersal strategy is employed by competing species (i.e. either [Formula: see text] or [Formula: see text] is non-constant) while it still holds true if both d(w) and [Formula: see text] are constant.

[Color characterization and its correlation with quality index during ripening of Rubus chingii].

The color of Rubus chingii was characterized by digital method, and the content of water extract, alcohol extract, total flavonoids, total polysaccharides, total polyphenols, ellagic acid, linden glycoside, kaophenol-3-O-rutin were determined. Correlation regression was used to analyze the correlation between color and composition. The results showed that L~* was positively correlated with total polyphenols, kaophenol-3-O-rutin and tilide, and moderately positively correlated with total flavones, ellagic acid and aqueous extracts. The a~* value was negatively correlated with total polyphenols, kaophenol-3-O-rutin, and linden glycosides, while was moderately correlated with total flavones, aqueous extracts, and ellagic acid. The b~* value was negatively correlated with the water extract, and moderately correlated with the content of total polyphenols, total polysaccharides, alcohol extract and kaophenol-3-O-rutin, which showed that R. chingii mature color had a significant correlation with material composition in the process of dynamic change. According to the law of dynamic change in the color and quality indexes, it is determined that the appropriate harvest time is in late April to May 1, while the fruit is not turn yellow. The agronomic traits related to fruit was(12.49±0.56) mm in diameter,(14.25±1.19)mm in height,(1.20±0.14) g in weight, the chroma L~* value was 52.87±3.14,a~* value was 2.01±1.58, b~* values was 28.31±3.88. The results lay a foundation for establishing an objective quantitative evaluation model of R. chingii color from experience.

[Effects of different application amounts of potassium fulvic acid on yield and quality of Fritillaria thunbergii].

Fritillaria thunbergii is a commonly used traditional Chinese medicine, which has the effects of clearing heat and resolving stagnation, eliminating phlegm and relieving cough. At present, it is mostly produced by cultivation, and the cultivation process requires application of base fertilizer, winter fertilizer, seedling fertilizer and late top dressing. Now farmyard manure or organic fertilizer can be used to replace the base fertilizer and winter fertilizer, but the research on the replacement of organic fertilizer has not been completed for the late top dressing. Potassium fulvate is a kind of fulvate fertilizer, which can not only regulate the growth of crops but also supplement potassium necessary for the growth of crops. In this paper, using F. thunbergii as a model plant with mature cultivation techniques, the effect of potassium fulvate on the quality and yield of rhizome traditional Chinese medicine F. thunbergii was systematically studied for the first time. HPLC-ELSD was used to determine the contents of peimine A and peimine B, hot dip method was used to determine the content of alcohol extract, and the SPAD-502 Plus chlorophyll meter was used to detect SPAD value. The results showed that applying 1.5 to 2.25 kg·hm~(-2) of potassium fulvic acid per hectare could effectively improve the yield of F. thunbergii and there was significantly difference between potassium phosphate monobasic and potassium fulvic acid in terms of quality. After the application of range 1.5 to 2.25 kg·hm~(-2) of potassium fulvic acid per hectare, the content of alcohol soluble extract of F. thunbergii was ranged 21.61% to 22.27%, the total amount of peimine A and peimine B were ranged 0.09% to 0.10%. Applying 1.5 to 2.25 kg·hm~(-2) of potassium fulvic acid per hectare could replace the conventional pure chemical fertilizer potassium phosphate monobasic, which could be used as top dressing fertilizer for the cultivation of F. thunbergii.

[Breeding and variety characteristics of a new variety of Fritillaria thunbergii "Zhebei 3"].

A new variety "Zhebei 3(Zhejiao Pharmaceutical 2018002)" was selected and bred from multi seeded Fritillaria thunbergii mutants by systematic breeding method. From 2012 to 2016, the traits assessment, disease resistance appraisal, plot ratios and regional trials of the variety were continuously carried out. The results showed that "Zhebei 3" emerged early and had late seedlings. The average growth period was about 100 days, which was 6 days and 12 days higher than the "Zhebei 1" and "Zhebei 2". The average yield was 5 095.5 kg·hm~(-2), which was 14.42% and 17.71% higher than of the control respectively. The average proliferation rate of bulbs was 261.2%, which was 37.46% and 31.58% higher than that of the control, respectively. The propagation coefficient of bulbs was about 1∶2.6, and the total amount of peimine and peiminine was 0.172 2%, which was 4.49% and 29.47% higher than the control, respectively. The identification of disease resistance showed that it was resistance to bulb stem(soft) rot, better than the control. "Zhebei 3" has stable characters, high yield, good quality, strong disease resistance, and moderate propagation coefficient which is suitable for planting in Zhejiang province.

[Correlation analysis between quality and habitat phenotype of Hovenia acerba].

The contents of dihydromyricetin and total flavonoids of Hovenia acerba seeds were detected by HPLC-DAD and UV spectrophotometer. And then the correlation between the habitat, phenotype and quality of H. acerba seeds were deeply studied. There were big differences in both appearance and quality among the H. acerba seeds from different places. It showed that the content of dihydromyricetin in H. acerba seeds was 0.41-9.81 mg•g⁻¹, and the content of total flavonoids was 5.52-21.98 mg•g⁻¹. The cluster analysis showed that the quality of H. acerba seeds was related to the habitat. The samples from Jianghan Plain Area showed relatively stable and excellent quality. According to the correlation analysis, there was a significant positive correlation between 1 000-seeds weight, red-black seeds ratio and the content of dihydromyricetin, while the content of total flavonoids was not related to the 1 000-seeds weight and red-black seeds ratio. So the 1 000-seeds weight and red-black seeds ratio could be used as an initial judgment of the quality of H. acerba seeds. As dihydromyricetin and total flavonoids content was not related, both dihydromyricetin and total flavonoids should be taken into account when the quality of H. acerba seeds was studied.

[Study on combined effects of chemical components for different flowers blossoming degree of yellow medicinal Chrysanthemum morifolium from Zhejiang].

The ingredients of five kinds of Zhejiang's yellow Chrysanthemum morifolium with different flower blossoming stages were comparatively analyzed. Polysaccharides, total flavonoids, volatile oil, alcohol extract, water extract, chlorogenic acid, luteolin, 3,5-O-dicaffeoyl quinic acid and fingerprint of the ingredient were determined as indicators. During flower blossoming stages, the ingredients of Ch. morifolium showed a big difference with a certain variation. At the early opening stage, the contents of flavonoids and volatile oil were higher, the content of chlorogenic acid, luteolin, 3,5-O-dicaffeoyl quinic acid were higher in the middle of the flowers 50% -80% fowers blossoming degree is the optimal time for harvest.

[Study on method of paeonia radix alba producing and concocting integration processing].

OBJECTIVE: To study the origin pre-treating and processing integration techniques of Paeonia Radix Alba. METHOD: Different processing integration techniques were adopted and compared with traditional processing techniques to determine drying rate, aqueous extracts and peoniflori content. RESULT: Half-dry slices baked at 100 degrees C for 20 min and steamed at 100 degrees C for 10 min had the highest peoniflori contents. Half-dry slices baked at 100 degrees C for 20 min had the highest content of aqueous extracts. Products processed with conventional method and sulfur-fumigation had the lowest content of aqueous extracts. CONCLUSION: The origin processing integration techniques of Paeonia Radix Alba lose less active ingredients than conventional processing methods.

Physicochemical characterizations of five Dioscorea alata L. starches from China.

D. alata is an important edible and medicinal plant in China. Its tuber is rich in starch but the understanding of the physiochemical properties of D. alata starch is limited. In order to explore the processing and application potential of different D. alata accessions in China, five kinds of D. alata starch (LY, WC, XT, GZ, SM) were isolated and characterized. The study showed that D. alata tubers contained abundant starch, enriched in amylose and resistant starch (RS). D. alata starches showed B-type or C-type diffraction pattern, had higher RS content and gelatinization temperature (GT), lower fa and viscosity when compared to D. opposita, D. esculenta, and D. nipponica. Among D. alata starches, D. alata (SM) showing the C-type diffraction pattern, had the lowest proportion of fa with 10.18 %, the highest amylose, RS2 and RS3 content of 40.24 %, 84.17 % and 10.48 % respectively, and the highest GT and viscosity. The results indicated that D. alata tubers are potential sources for novel starch with high amylose and RS content, and provided a theoretical basis for further utilizations of D. alata starch in food processing and industry application.

Traveling wave solutions of a singular Keller-Segel system with logistic source.

This paper is concerned with the traveling wave solutions of a singular Keller-Segel system modeling chemotactic movement of biological species with logistic growth. We first show the existence of traveling wave solutions with zero chemical diffusion in $ \mathbb{R} $. We then show the existence of traveling wave solutions with small chemical diffusion by the geometric singular perturbation theory and establish the zero diffusion limit of traveling wave solutions. Furthermore, we show that the traveling wave solutions are linearly unstable in the Sobolev space $ H^1(\mathbb{R}) \times H^2(\mathbb{R}) $ by the spectral analysis. Finally we use numerical simulations to illustrate the stabilization of traveling wave profiles with fast decay initial data and numerically demonstrate the effect of system parameters on the wave propagation dynamics.

[Study on method of Corydalis yanhusuo producing and concocting integration processing].

OBJECTIVE: To establish integration processing method for pretreating and vinegar producing Corydalis yanhusuo. METHOD: Different processing methods were contrasted with the traditional processing technology, and contents of corydalis B, water extract and ethanol extract in samples of different processing products were determined. RESULT: The content of corydalis B were best in the samples of vacuumizing C. yanhusuo chips scaked in rice vinegar for twice or soaked in rice vinegar after chip drying. The water extract was highest in the samples of chip soaked in rice vinegar after drying, followed with chip vacuumizing twice, and there were no remarkable difference between the other samples and the traditional process. The difference of ethanol extract was not remarkable in all the samples. CONCLUSION: The study provide the feasibility of C. yanhusuo producing and concocting integration processing.

[Study on the initial processing of Corydalis yanhusuo].

OBJECTIVE: To establish initial processing technology of Corydalis yanhusuo. METHODS: Investigated the effect of the factors such as slice method, dry method, drying temperature on the content of water-extract, ethanol-extract, effective component in Corydalis yanhusuo pieces. Compared the quality with that of the traditional initial processing samples. RESULTS: The best initial process method was: cut fresh Corydalis yanhusuo into 4 - 5 mm thick slices, dry at 70 - 80 degrees C or microwave dry. CONCLUSION: The study provides theoretical base for modifying the initial processing.

[Factors influence volatile oil content in Ocimun basilicum introduced from Xinjiang province to south-east China].

OBJECTIVE: To obtain the information on ecological adaptation of Ocimun basilicum introduced from Xinjiang to Hangzhou and study the effect of different harvesting times, drying methods, and different organs of Ocimun basilicum on Volatile oil content METHODS: Extraction was undertaken according to The Pharmacopoeia of China, 2010 edition. RESULTS: Sun-drying was the most efficient way to obtain Volatile oil compared with other methods. The largest biomass was harvested at 3rd, September. Furthermore, Volatile oil was found to accumulate mostly in the flowers and little in the stems. CONCLUSION: Ocimun basilicum can readily inhabit in Hangzhou and its economic value can be significant improved by growing two seasons per year. Only harvest leaves and flowers can significantly reduce the cost for transport and also increase oil extract rate of Volatile oil.

Evaluation and application of an efficient plant DNA extraction protocol for laboratory and field testing.

Nucleic acids in plant tissue lysates can be captured quickly by a cellulose filter paper and prepared for amplification after a quick purification. In this study, a published filter paper strip method was modified by sticking the filter paper on a polyvinyl chloride resin (PVC) sheet. This modified method is named EZ-D, for EASY DNA extraction. Compared with the original cetyl trimethylammonium bromide (CTAB) method, DNA extracted by EZ-D is more efficient in polymerase chain reaction (PCR) amplification due to the more stable performance of the EZ-D stick. The EZ-D method is also faster, easier, and cheaper. PCR analyses showed that DNA extracted from several types of plant tissues by EZ-D was appropriate for specific identification of biological samples. A regular PCR reaction can detect the EZ-D-extracted DNA template at concentration as low as 0.1 ng/µL. Evaluation of the EZ-D showed that DNA extracts could be successfully amplified by PCR reaction for DNA fragments up to 3000 bp in length and up to 80% in GC content. EZ-D was successfully used for DNA extraction from a variety of plant species and plant tissues. Moreover, when EZ-D was combined with the loop-mediated isothermal amplification (LAMP) method, DNA identification of biological samples could be achieved without the need for specialized equipment. As an optimized DNA purification method, EZ-D shows great advantages in application and can be used widely in laboratories where equipment is limited and rapid results are required.

Selective hydrosilylation of allyl chloride with trichlorosilane.

The transition-metal-catalysed hydrosilylation reaction of alkenes is one of the most important catalytic reactions in the silicon industry. In this field, intensive studies have been thus far performed in the development of base-metal catalysts due to increased emphasis on environmental sustainability. However, one big drawback remains to be overcome in this field: the limited functional group compatibility of the currently available Pt hydrosilylation catalysts in the silicon industry. This is a serious issue in the production of trichloro(3-chloropropyl)silane, which is industrially synthesized on the order of several thousand tons per year as a key intermediate to access various silane coupling agents. In the present study, an efficient hydrosilylation reaction of allyl chloride with trichlorosilane is achieved using the Rh(I) catalyst [RhCl(dppbzF)]2 (dppbzF = 1,2-bis(diphenylphosphino)-3,4,5,6-tetrafluorobenzene) to selectively form trichloro(3-chloropropyl)silane. The catalyst enables drastically improved efficiency (turnover number, TON, 140,000) and selectivity (>99%) to be achieved compared to conventional Pt catalysts.

Traveling wave solutions from microscopic to macroscopic chemotaxis models.

In this paper, we study the existence and nonexistence of traveling wave solutions for the one-dimensional microscopic and macroscopic chemotaxis models. The microscopic model is based on the velocity jump process of Othmer et al. (SIAM J Appl Math 57:1044-1081, 1997). The macroscopic model, which can be shown to be the parabolic limit of the microscopic model, is the classical Keller-Segel model, (Keller and Segel in J Theor Biol 30:225-234; 377-380, 1971). In both models, the chemosensitivity function is given by the derivative of a potential function, Phi(v), which must be unbounded below at some point for the existence of traveling wave solutions. Thus, we consider two examples: Phi(v) = ln V and Phi(v) = ln[v/(1 - v)]. The mathematical problem reduces to proving the existence or nonexistence of solutions to a nonlinear boundary value problem with variable coefficient on R. The main purpose of this paper is to identify the relationships between the two models through their traveling waves, from which we can observe how information are lost, retained, or created during the transition from the microscopic model to the macroscopic model. Moreover, the underlying biological implications of our results are discussed.

Phosphorus and oxygen co-doped composite electrode with hierarchical electronic and ionic mixed conducting networks for vanadium redox flow batteries.

The hierarchical electronic and ionic mixed conducting networks build in graphite felt electrodes possess excellent electrocatalytic activity and faster electronic and ionic conduction, resulting in an enhanced energy efficiency of vanadium redox flow batteries with durable life for 1000 cycles and a high discharge capacity of 10.1 A h L-1 at a current density of 350 mA cm-2.

[Effect of environmental factors on growth of Huperzia serrata].

OBJECTIVE: To establish and optimize the cultivation systems for wild Huperzia serrata, through assessing the effects of environmental factors on its growth. METHOD: H. serrata was planted under natural field condition, the growth status of H. serrata under different light intensities, temperatures, relative humidity (R. H.), fertilizer levels, and so on were investigated and analyzed. RESULT: H. serrata grew nicely under following environmental conditions: temperature ranging from 18.9-26.3 degrees C, R. H. ranging from 81%-90% and 1330-3000 lx light intensity. A cultivation system, in which H. serrata was planted in the bamboo forest and did not occupy the arable land, was established through the study. CONCLUSION: Concluded that light intensity and R. H are the two factors which greatly confine the growth of H. serrata. As long as the levels of the above two factors meets the demands, H. serrata could be cultivated.

[Study on correlation between Atractylodes macrocephala viability and germination rate].

OBJECTIVE: To screen the optimized methods for detection seed viability and germination rate determination of Atractylodes macrocephala, and determine the relationship between seed viability and germination rate. METHOD: There were four methods, which including 2,3,5-triphynel tetrazolilum chloride (TTC) staining, red ink staining, BTB staining and Nongjia method, to evaluate the 12 A. macrocephala local varieties'seed viability and measure their germination rate. RESULT: Seed viability of A. macrocephala using TTC staining ranked the first compared to that of other three methods. Seed viability was significantly related with germination rate using TTC method. Their correlation coefficient reached 0.915 and regression equation was also found out between seed viability (X) and germination rate (Y), which was Y = -0.083 4 + 0.995 4X. CONCLUSION: TTC staining was the optimal method to determine A. macrocephala seed vitality. Furthermore, seed viability was significant related with germination rate of A. macrocephala.