Qualitative analysis of aromatic compounds via 1D TOCSY techniques

The aromatic compounds,including o-xylene,m-xylene,p-xylene,and ethylbenzene,primarily originate from the catalytic reforming of crude oil,and have a wide variety of applications.However,because of similar physical and chemical properties,these compounds are difficult to be identified by gas chromatography(GC)without standard samples.With the development of modern nuclear magnetic resonance(NMR)techniques,NMR has emerged as a powerful and efficient tool for the rapid analysis of complex and crude mixtures without purification.In this study,the parameters of one-dimensional(1D)total correlation spectroscopy(TOCSY)NMR techniques,including 1D selective gradient TOCSY and 1D chemicalshift-selective filtration(CSSF)with TOCSY,were optimized to obtain comprehensive molecular structure information.The results indicate that the overlapped signals in NMR spectra of nonpolar aromatic compounds(including o-xylene,m-xylene,p-xylene and ethylbenzene),polar aromatic compounds(benzyl alcohol,benzaldehyde,benzoic acid),and aromatic compounds with additional conjugated bonds(styrene)can be resolved in 1D TOCSY.More importantly,full molecular structures can be clearly distinguished by setting appropriate mixing time in 1D TOCSY.This approach simplifies the NMR spectra,provides structural information of entire molecules,and can be applied for the analysis of other structural isomers.

Qualitative and Quantitative Analysis of Alkaloids in Cortex Phellodendri by HPLC-ESI-MS/MS and HPLC-DAD

A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer（HPLC-ESI-MS/MS） coupled with a photodiode array detector（HPLC-DAD） and principal component analysis（PCA） was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri（CP） samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis（CPC） and Cortex Phellodendri Amurensis（CPA）. Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC（58.75 mg/g） was higher than that in CPA（9.16 mg/g）, while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines.

Appropriate choice of collision-induced dissociation energy for qualitative analysis of notoginsenosides based on liquid chromatography hybrid ion trap time-of-flight mass spectrometry

Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possesses both the MS^n ability of ion trap and the excellent resolution of a time-of-flight and has been widely used to identify drug metabolites and determine trace multi-components in natural products. Collision energy, one of the most important factors in acquiring MS^n information, could be set freely in the range of 10%–400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides were obtained based on accurate MS^2 and MS^3 measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. The extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract were produced under a series of collision energies and compared to screen the optimum collision energies values for MS^2 and MS^3. The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS^2 collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. Addtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS^3 stage.

Qualitative Analysis and Quality Evaluation of Cnidium monnieri Using UHPLC-ESI-Q-TOF/MS

Objective To identify the coumarins constituents in Cnidium monnieri and classify ten samples into three groups and this helpful chemical information could be used for the further pharmacological and clinical study on C. monnieri. Methods Qualitative analysis of coumarins in C. monnieri was detected by UHPLC-ESI-Q-TOF/MS. Quadrupole TOF/MS in either full scan mode or extracted ion mode was used for the qualitative analysis of the constituents. Relative peak area of each component was used for the hierarchical cluster analysis. Results According to UHPLC-ESI-QTOF-MS data, chemical structures of 28 coumarins in the fruits of C. monnieri were identified, including 19 simple coumarins, seven linear coumarins, and two angular coumarins. Among these constituents, ten coumarins were firstly identified in C. monnieri. In addition, hierarchical cluster analysis suggested that C. monnieri from different regions could be classified into four groups, and this clustering was correlated to the distribution significantly, Xuzhou could be regarded as the genuine producing area. Conclusion UHPLC-ESI-Q-TOF-MS is a viable method for qualitative analysis and quality evaluation of coumarins from the fruit of C. monnieri. Coumarins in C. monnieri exists intra-species variance, which indicates significant meaning for the quality control and choice of famous region drug for C. monnieri in the clinic medication.

REGION QUALITATIVE ANALYSIS OF PREDATOR-PREY SYSTEMS ON TIME SCALES

We first investigate some basic properties of dynamic equations on time scales,and propose contained curves to describe the jump direction of the discrete points.Then we perform qualitative analysis regarding the planar predator-prey systems on time scales,thereby obtain two theorems of this system.At last,we emulate application examples to discuss the parameters of the system.

DETERMINING HYDROCARBON PROSPECTIVE ZONE USING THE COMBINATION OF QUALITATIVE ANALYSIS AND FUZZY LOGIC METHOD

Hydrocarbon prospective zone is a certain layer in a reservoir which is estimated producing oil. The geologists use the qualitative analysis method to find the prospect layers. The research used five variables modeled by three fuzzy membership functions and eight rules of fuzzy logic. The rules cause insensitiveness in the working system. This study therefore was conducted by modeling each of input variables into different models using 36 rules. It aims to determine the existence of hydrocarbon prospective zone through a qualitative analysis in a reservoir using fuzzy inference system with Mamdani method. The data were taken from well log data in reservoir ＂X＂. There were some steps in doing this study, including fuzzification, inference system, and defuzzification. The result showed 99 prospect layers from 3000 layers in reservoir ＂X＂ with 97.7% of accuracy.

Qualitative Analysis and Approximate Damped Oscillatory Solutions for a Kind of Nonlinear Dispersive-dissipative Equation

This paper makes qualitative analysis to the bounded traveling wave solutions for a kind of nonlinear dispersive-dissipative equation, and considers its solving problem. The relation is investigated between behavior of its solution and the dissipation coefficient. Further, all approximate damped oscillatory solutions when dissipation coefficient is small are presented by utilizing the method of undetermined coefficients according to the theory of rotated vector field in planar dynamical systems. Finally, error estimate is given by establishing the integral equation which reflects the relation between approximate and exact damped oscillatory solutions applying the idea of homogenization principle.

Qualitative Analysis and Solutions of Bounded Traveling Wave for B-BBM Equation

In this paper, we apply the theory of planar dynamical systems to carry out qualitative analysis for the dynamical system corresponding to B-BBM equation, and obtain global phase portraits under various parameter conditions. Then, the relations between the behaviors of bounded traveling wave solutions and the dissipation coeffiicient μ are investigated. We find that a bounded traveling wave solution appears as a kink profile solitary wave solution when μ is more than the critical value obtained in this paper, while a bounded traveling wave solution appears as a damped oscillatory solution when μ is less than it. Furthermore, we explain the solitary wave solutions obtained in previous literature, and point out their positions in global phase portraits. In the meantime, approximate damped oscillatory solutions are given by means of undetermined coefficients method. Finally, based on integral equations that reflect the relations between the approximate damped oscillatory solutions and the implicit exact damped oscillatory solutions, error estimates for the approximate solutions are presented.

QUALITATIVE ANALYSIS FOR A MATHEMATICAL MODEL OF AIDS

In this paper a mathematical model of AIDS is investigated.The conditions of the existence of equilibria and local stability of equilibria are given.The existences of transcritical bifurcation and Hopf bifurcation are also considered.in particular,the conditions for the existence of Hopf bifurcation can be given in terms of the coefficients of the characteristic equation.The method extends the application of the Hopf bifurcation theorem to higher differential equations which occur in biological models,chemical models,and epidemiological models etc.

Qualitative Analysis of Van der Pol Type Equation with Periodic Forcing Term

In this paper we analyze the qualitative behaviour of the equation ε+q(X) +εX=bp(t), where e is a small parameter.We divide the interval of parameter b into four sets of subintervals,A, B,C and D.For bA,B or D,we discuss the different structures of the attractors of the equation and their stabilities.When chaotic phenomena appear,we also estimate the entropy.For bC,the set of bifurcation intervals,we analyze the bifurcating type and get a series of consequences from the results of Newhouse and Palis.

Qualitative Analysis of a Class of Competitive and Cooperative Systems

Hirsch[1,2] studied the limiting behavior of solutions of competitive or cooperative systems, and showed that ifL is an ω-limit set of a three-dimensional cooperative system, which contains no equilibrium, thenL is a nonattracting closed orbit. Smith[3] considered a three-dimensional irreducible competitive system and showed that an ω-limit set containing no equilibrium must be a closed orbit which has a simple Floquet multiplier λ<1, and may be attracting. In this paper we carry out the qualitative analysis of a class of competitive and cooperative systems, and a generalization of the result of Levine[4] is given. The stability problem of closed orbits raised in [5] and [6] is resolved.

Novel Investigation of Stochastic Fractional Differential Equations Measles Model via the White Noise and Global Derivative Operator Depending on Mittag-Leffler Kernel

Because of the features involved with their varied kernels,differential operators relying on convolution formulations have been acknowledged as effective mathematical resources for modeling real-world issues.In this paper,we constructed a stochastic fractional framework of measles spreading mechanisms with dual medication immunization considering the exponential decay and Mittag-Leffler kernels.In this approach,the overall population was separated into five cohorts.Furthermore,the descriptive behavior of the system was investigated,including prerequisites for the positivity of solutions,invariant domain of the solution,presence and stability of equilibrium points,and sensitivity analysis.We included a stochastic element in every cohort and employed linear growth and Lipschitz criteria to show the existence and uniqueness of solutions.Several numerical simulations for various fractional orders and randomization intensities are illustrated.

Analysis on the Configuration Path of Improving the Quality and Efficiency of County-Level Libraries in China

County-level libraries have an inescapable responsibility for cultivating local cultural identity and realizing rural revitalization.Therefore,we analyzed factors that afect the service fficiency of gass-1oots libraries in Henan Province through a field investigation and qualitative comparative analysis(QCA),and proposed a higlh-efficiency configuration.In addition,we put forward the strategy of improving the quality and efficiency of our country's county-level libraries in the electonic information age.

SYMBOLIC COMPUTATION FOR THE QUALITATIVE THEORY OF DIFFERENTIAL EQUATIONS

This paper provides a survey on symbolic computational approaches for the analysis of qualitative behaviors of systems of ordinary differential equations,focusing on symbolic and algebraic analysis for the local stability and bifurcation of limit cycles in the neighborhoods of equilibria and periodic orbits of the systems,with a highlight on applications to computational biology.

Construction of a General Standard Molecule for the Qualitative Detection in Different Transgenic Foodcrops

Now every laboratory is facing a common problem that is seriously lacking in the standard reference molecule in the GMC detecting research center. Constructing the recombinant plasmid is the urgent demand. In order to overcome this problem, this study respectively cloned CrylA（B）, BAR, CP4-EPSPS, PAT and RBCL genes into PMD 18-T vector. This constructed plasmid could be used as the standard reference molecule in the qualitative detecting of the exogenous CP4-EPSPS gene, CrylA（B） gene, BAR gene and PAT gene. Identification by double restriction endonuclease digestion and identification by PCR proved that the test result was positive. All of these indicated that the established reference molecules in this study were suitable for the qualitative analysis standard of this GMC detection.

Exploring the Evolutionary Path of Digital Financial Inclusion in Guangdong Province,China

This study explores the development trajectory of digital financial inclusion in 21 cities in Guangdong Province through fuzzy-set qualitative comparative analysis(fsQCA).The findings emphasize that the success of digital financial inclusion goes beyond individual dimensions,forming a systematic initiative marked by multifaceted interaction among different disciplines.In the trajectory of high-level digital inclusive finance development,the study identifies economic prosperity and technological innovation as crucial elements,highlighting their centrality,and elucidates the synergistic collaboration between market mechanisms and government guidance.Furthermore,the study emphasizes the government’s pivotal role in supporting market mechanisms and guiding policies,highlighting the need to achieve a nuanced equilibrium in the digital financial inclusion strategy.In contrast,non-high-level development paths of digital inclusive finance show a spectrum of diversities,emphasizing the critical roles played by economic fundamentals,government regulation,market mechanisms,and other contextual factors in different trajectories.Regarding policy implications,the study emphasizes the comprehensive and systemic nature inherent in the development of digital inclusive finance.It proposes four policy recommendations,including integrating development strategies,emphasizing scientific and technological innovation and economic development,achieving a delicate balance between market mechanisms and government guidance,and providing precise policy support.These insights provide valuable lessons for shaping digital inclusive financial policies in Guangdong Province and beyond,offering profound insights for strategically constructing robust digital financial ecosystems.

A Causal Configuration Analysis of Payment Decision Drivers in Paid Q&A

Purpose:This paper examines factors of payment decision as well as the role each factor plays in casual configurations leading to high payment intention under systematic and heuristic information processing routes.Design/methodology/approach:Based on heuristic-systematic model(HSM),we propose a configurational analytic framework to investigate complex casual relationships between influencing factors and payment decision.In line with this approach,we use fuzzy-set qualitative comparative analysis(fsQCA)to analyze data crawled from Zhihu.com.Findings:The number of previous consultations is a necessary element in all five equivalent configurations which lead to high intention in payment decision.The heuristic processing route plays a core role while the systematic processing route plays a peripheral role in payment decision-making process.Research limitations:Research is limited in that moderating effect of professional fields has not been considered in the framework.Practical implications:Configurations in results can assist managers of knowledge communities and paid Q&A service providers in the management of information elements to motivate more payment decision.Originality/value:This paper is one of the few studies to apply HSM theory and fsQCA method with respect to the payment decision in paid Q&A.

Intensive Care Nurses’Experiences of Caring for Intubated Patients under Light Sedation:A Qualitative Study

Introduction: Previous studies have shown that a light sedation level is beneficial for intubated patients in the Intensive care unit (ICU). Aim: This study aimed to describe intensive care nurses’ experiences of caring for intubated patients under light sedation. Methods: This study was an explorative descriptive qualitative study. Data were collected from 12 intensive care nurses by three focus group interviews and analyzed using qualitative content analysis. Findings: Five categories emerged from the data: 1) the importance of verbal communication and the nurses’ presence, 2) feelings of frustration and heavy workload, 3) assessment of patients’ pain and anxiety, 4) the nurses’ desire for the development of guidelines, and 5) being inspired by the care. Conclusion: The study found that intensive care nurses were positive towards light sedation care but the organization of care did not support them as the patients cared for with light sedation treatments demanded their physical presence at patients’ bed site.

Influence of dissipation on solitary wave solution to generalized Boussinesq equation

This paper uses the theory of planar dynamic systems and the knowledge of reaction-diffusion equations,and then studies the bounded traveling wave solution of the generalized Boussinesq equation affected by dissipation and the influence of dissipation on solitary waves.The dynamic system corresponding to the traveling wave solution of the equation is qualitatively analyzed in detail.The influence of the dissipation coefficient on the solution behavior of the bounded traveling wave is studied,and the critical values that can describe the magnitude of the dissipation effect are,respectively,found for the two cases of b_3<0 and b_3>0 in the equation.The results show that,when the dissipation effect is significant(i.e.,r is greater than the critical value in a certain situation),the traveling wave solution to the generalized Boussinesq equation appears as a kink-shaped solitary wave solution;when the dissipation effect is small(i.e.,r is smaller than the critical value in a certain situation),the traveling wave solution to the equation appears as the oscillation attenuation solution.By using the hypothesis undetermined method,all possible solitary wave solutions to the equation when there is no dissipation effect(i.e.,r=0)and the partial kink-shaped solitary wave solution when the dissipation effect is significant are obtained;in particular,when the dissipation effect is small,an approximate solution of the oscillation attenuation solution can be achieved.This paper is further based on the idea of the homogenization principles.By establishing an integral equation reflecting the relationship between the approximate solution of the oscillation attenuation solution and the exact solution obtained in the paper,and by investigating the asymptotic behavior of the solution at infinity,the error estimate between the approximate solution of the oscillation attenuation solution and the exact solution is obtained,which is an infinitesimal amount that decays exponentially.The influence of the dissipation coefficient on the amplitude,frequency,period,and energy of the bounded traveling wave solution of the equation is also discussed.

Qualitative and quantitative analysis ofβ-sitosterol marker in virgin camellia oil and virgin olive oil

Camellia oil and olive oil with superior economic value are easily adulterated with other,cheaper oils.It is difficult to identify both oils by traditional methods because of their similar fatty acid profiles.In the present study,a novel method for qualitative and quantitative analysis ofβ-sitosterol using GC/MS and GC/FID was developed to identify camellia oil and olive oil.The method validation ofβ-sitosterol analysis showed good linearity and satisfactory values for recovery,accuracy,precision,and repeatability.The linear regression coefficient(R^(2))of the calibration curve was 0.9985.An acceptable limit of detection(0.36 mg/100 g)and limit of quantification(1.20 mg/100 g)were achieved.The spiked recoveries were 95.0%to 100.3%.The relative standard deviation(RSD)of within-day precision was less than 3.26%,and the RSD of retention times and peak areas for repeatability were within 0.03%and 1.08%,respectively.The contents ofβ-sitosterol in virgin camellia oil and virgin olive oil were in the range of 14.1–30.2 mg/100 g and 94.3–173.2 mg/100 g,respectively,indicating that theβ-sitosterol content in the former is seven times that in the latter,andβ-sitosterol could be a potential marker for the authentication and adulteration detection of both oils.