Retention Indices Research Articles

On some extended energy of graphs and their applications

In this paper, we established a relation between the extended energy of graphs such as the first and second Zagreb energy, Randi?c energy, reciprocal Randi?c energy, and the atom-bond connectivity energy with some thermodynamic properties of benzenoid hydrocarbons. We have seen that these indices are well correlated to the boiling point (BP), Kovats retention index (RI), entropy (S), enthalpy of formation (?Hf), octanol-water partition coefficient (logP), and acentric factor (?) of benzenoid hydrocarbons.

Comparison of Thallium-201 Uptake and Retention Indices for the Evaluation of Glioma Grading

Comparison of Thallium-201 Uptake and Retention Indices for the Evaluation of Glioma Grading

Chromatography of Solanum habrochaites extracts with the first record of the docosanoate, hexadecanoate and octadecanoate ethyls in this plant and in Solanaceae.

The increasing need for sustainable alternatives to synthetic insecticides has driven the analysis of extracts from Solanum habrochaites, a wild tomato, through fractionated column chromatography. Potential bioactive compounds for pest management, a clean and promising biotechnological solution, have been reported from this plant. The objective is to provide detailed gas chromatography data, including peaks, structural formulas, and retention indices for the extracts of S. habrochaites aerial parts. Column chromatographic analysis was conducted with five fractions (F1, F2, F5, F3, and F4) of S. habrochaites extracts. Long-chain hydrocarbons such as hexadecanoic acid and docosano were identified in the F1 fraction; fatty acid esters, including hexadecanoate and octadecenoate ethyls in the F2 and methyl ketones, with tridecan-2-one as the major component in the F5, while no identifiable compounds were disclosed in the F3 and F4 fractions. The column chromatography provided valuable insights into compounds in the F1, F2, and F5 fractions of S. habrochaites extracts, highlighting fatty acid esters, long-chain hydrocarbons, and methyl ketones. The bioactive compounds, from extracts of this plant, including the first record of the docosanoate, hexadecanoate and octadecanoate ethyls in S. habrochaites and Solanaceae, reinforces their promising biological application in different areas of science.

PENGARUH PROSES PENGERINGAN TERHADAP NILAI PLASTISITAS RETENSI KARET REMAH

The crumb rubber SIR 20 originating from the processing of natural rubber (Hevea brasiliensis) plays a crucial role as a primary export commodity in the Indonesian economy. Due to its diverse applications in consumer products and medical devices, natural rubber possesses unique properties such as resilience, elasticity, and wear resistance. The drying process of natural rubber at high temperatures significantly affects its plasticity and strength. This research explores the influence of temperature (130-155°C) and drying time (77-110 minutes) on the plasticity of crumb rubber SIR 20. The results indicate that the PRI (Plasticity Retention Index) values still meet quality standards within certain ranges. The optimal PRI value of 75-76% is obtained at a temperature of 130-135°C for 77 minutes. Increasing the operating temperature and drying time leads to a significant decrease in PRI values due to thermal oxidation occurring in the molecular structure of rubber, thereby affecting the quality of crumb rubber. The findings from this study on the impact of temperature and drying time can provide technical information for the rubber industry to maintain product quality while minimizing environmental impact.

INVESTIGATION OF THE INTERACTION OF WATER-GLYCERIN MIXTURE AND SAWDUST OF LARCH LARIX SIBIRICA LEDEB (PINACEAE)

The interaction of the eutectic plasticizer – aqua complex «glycerin − water» with sawdust of larch wood of two fractional compositions was studied: a fine fraction (wood flour) and a coarse fraction (sawdust) with a particle size of 1−3 mm. The methods of optical microscopy were used to study the surface properties of samples, to measure the dynamic viscosity of spent solutions on a Brookfield viscometer; to measure the VGS retention index, a modified Jaime water retention technique was used. The obtained data are compared with the results of previous studies, in which it was shown that arabinogalactan (AG) performs the functions of a eutectic plasticizer in the structure of larch wood and is in the form of an aqua complex «AG–water». It was found that the amount of the attached aqua-complex – «glycerin − water» to the samples of larch sawdust corresponds to the amount of AG previously extracted from sawdust. The process of replacing the aqua-complex «AG − water» with the aqua-complex «glycerin – water» is analyzed on the diagram of relaxation states «two polymers – solvent». The experimental results are interpreted on the basis of previously obtained data on the effect of water and glycerin on the relaxation state of polymer components of wood. The fundamental difference between the two eutectic plasticizers is demonstrated: if, when drying larch wood, the destruction of the aqua-complex «AG − water» leads to the transfer of polymer components of wood from a highly elastic to a glassy state, then when using the aqua-complex «glycerin − water» (VGS), water is removed during drying, and the remaining glycerin ensures the preservation of polymer components of wood in a highly elastic state. The possible technological aspects of the revealed patterns are considered.

Phytochemical profile and antimicrobial activity of essential oils from two Syzygium species against selected oral pathogens

BackgroundThe genus Syzygium (Myrtaceae) comprises several essential oil-rich species that are utilized traditionally for treating tooth infections and toothache. The current study aimed to extract essential oils (EOs) from the leaves of Syzygium samarangense and Syzygium malaccense cultivated in Egypt for the first time and screen their antimicrobial potential against oral-related pathogens.MethodsThe intended EOs were extracted using hydrodistillation (HD) by boiling fresh leaves with distilled water; supercritical fluid (SF) by extracting the dried leaves using supercritical CO2 at 40 °C and 150 bar; and the headspace (HS) in which the fresh leaves were heated in a glass vial and the vaporized aroma were analyzed. The volatile constituents were analyzed using GC/MS and identified by comparing the experimental Kovats' retention indices with the literature. The antimicrobial activity was assessed against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans using agar diffusion, microwell dilution, and biofilm formation assays. Statistical significance (p < 0.05) was determined by applying one-way ANOVA and Duncan's post hoc test.ResultsThe yield of the extracted EOs differs between the applied methods, and the SF approach harvested the maximum (0.52–0.46%). The GC–MS analysis of SF EOs revealed a discrepancy between the two species. Since S. malaccense showed an abundance of hydrocarbons represented mainly by squalene (60.60%), S. samarangense was deemed to have oxygenated sesquiterpenes exemplified in globulol (52.09%). On the other side, the HD and HS EOs were sequentially comparable, while differed in the percentage of their majors. γ-terpinene (33.06%) pioneered the HS-derived aroma of S. malaccense, while S. samarangense was abundant with α-pinene (30.18%). Concurrently, the HD EOs of S. malaccense and S. samarangense were commonly denoted by caryophyllene oxide (8.19%-18.48%), p-cymene (16.02%- 19.50%), and γ-terpinene (12.20%-17.84). Ultimately, both species EOs exhibited broad-spectrum antimicrobial potential, although the HD EO was more potent than the SF EO. The HD EOs of both species potently inhibited the growth of E. coli (MIC 3.75 µL/mL) and suppressed C. albicans biofilm formation by 83.43 and 87.27%, respectively. The SF-EOs efficiently suppressed the biofilm formation of Gram-positive bacteria by 76.45%-82.95%.ConclusionEOs extracted from both species by different methods possessed a unique blend of volatile components with broad-spectrum antimicrobial activity. They were promoted as bioactive hits for controlling oral infections, however further investigations concerning their safety in clinical settings are needed.

A chemical derivatization-based pseudotargeted liquid chromatography-tandem mass spectrometry method for sensitive and high coverage determination of bile acids in human serum

Global profiling of bile acids (BAs) is imperative for understand their function and disease pathogenesis. But it is still a challenging task, as the collision-induced dissociation (CID) fragment ions of unconjugated BAs showed low ion intensities to insufficient analysis. Herein, we developed a highly sensitive method for pseudotargeted profiling of BAs by chemical derivatization. In the developed method, a labeling reagent, 2-dimethylaminoethylamine (DMED), was adopted to label the carboxyl group of BAs. The results demonstrated that the detection sensitivities of unconjugated BAs were increased by 4–200 folds after DMED-labeling. Moreover, to profile other potential BAs not included in the 91 known targets, diverse survey experiments were performed on Qtrap-MS to search BAs for both precursor and fragment ion species, and retention index (RI) strategy was adopted to facilitate the identification of isomers. Finally, MRM-based LC-MS/MS method was validated for the pseudotargeted profiling of the BAs submetabolome with good linearity (r2 ≥ 0.990 for 89 known BAs) and high sensitivity (0.05–0.5 ng/mL for unconjugated BAs), covering unconjugated, glycine, taurine, sulfuric acid, glucuronic acid, and as well as those doubly-conjugated with above types. With this method, a total of 107 BAs, covering 54 BAs identified by authentic standards and 53 BAs candidates, were successfully determined in human serum of women with intrahepatic cholestasis of pregnancy (ICP). Multivariate analysis revealed deferentially expressed BAs. ICP disease altered the BAs profile with a reduced proportion of unconjugated, sulfate- and doubly-conjugated BAs and an increased proportion of glycine and taurine conjugates. Altered proportion and profile of BAs in ICP groups were gradually recovered during the ursodeoxycholic acid (UDCA) therapy. Overall, the strategy of DMED-labeling technique combined with diverse survey experiments is sufficiently sensitive and robust to comprehensively analysis of metabolic profiling of BAs in human serum.

Chemical profile of essential oils of the Costa Rican native tree Myrcianthes storkii (Myrtaceae)

Introduction: The genus Myrcianthes ranges from southern Florida to Chile, including the Caribbean, and the species Myrcianthes storkii is a shrub or tree found in Costa Rica and western Panama, in wet to very rainy, cloud, and oak forests (altitude 1300-3150m). Objective: To identify the chemical composition of essential oils from leaves, floral buds, and twigs of M. storkii of Costa Rica. Methods: We obtained the essential oils through hydrodistillation in a Clevenger-type apparatus. The chemical composition of the oils was done by GC/FID and GC/MS, using the retention indices on DB-5 and Carbowax types of capillary columns in addition to mass spectra. Results: The oils consisted mainly of terpenoids (55,45-87,75%). A total of 281 compounds accounted for 91,27-74,56% of the total amount of oils. The major constituents from the leaf oil were myrcene (17,44%), cis-calamenene (12,60%), α-pinene (5,48%), (E)-caryophyllene (5,16%), limonene (3,91%), p-cymene (3,71%), 1,8-cineole (2,80%), and α-humulene (2,80%). The floral bud essential oil consisted mainly of α-pinene (15,23%), cis-calamenene (12,70%), myrcene (8,59%), 1,8-cineole (4,26%), germacrene B (3,65%), α-humulene (3,55%), and (E)-caryophyllene oxide (2,93%). The major components of twig oil were cis-calamenene (11,31%), palmitic acid (7,99%), (E)-caryophyllene (4,68%), -cadinene (3,28%), cubenol (3,24%), and (Z)-caryophyllene oxide (2,94%). Conclusion: The presence of a significant quantity of myrcene and cis-calamenene seems to be characteristic of this species.

Identification of the Chemical Components Derived from the Two‐Phase Electrocoagulation of Diesel Fuel

AbstractIn this study, two‐phase electrocoagulation (EC) approach was developed and used to investigate blend of bio‐diesel and petro‐diesel (B10) stability under the electrochemical treatment. Gas chromatography‐mass spectrometry (GC‐MS) was used to analyze the aliquots before and after the reaction. The major compounds were alkanes and aromatic compounds with the minor contents of aldehydes, ketones, esters, alkenes, alkynes, halogens, oxygenated compounds, and heterocyclic compounds. The selected condition for the reaction was 10 V and 60 min which resulted in 9.9×109 counts per s total peak area of compounds containing from nine to seventeen carbon atoms (C9 to C17) compared with 6.8×108 counts per s for the control. The peak areas of the straight chain alkanes increased from 12 % to 33 % of the total peak areas observed after the experiment. Compounds with higher peak areas were found between C12 to C14 with the retention indices range of 1155–1678. The EC treatment mainly increased the straight and branched alkane and alcohol contents with the decreasing contents of branched cyclic alkanes. The developed system could be adapted to study the stability of other types of fuels. This is cost effective and can be performed within an hour at room temperature under atmospheric pressure.

An Integrated Workflow Assisted by In Silico Predictions To Expand the List of Priority Polycyclic Aromatic Compounds.

The limited information in existing mass spectral libraries hinders an accurate understanding of the composition, behavior, and toxicity of organic pollutants. In this study, a total of 350 polycyclic aromatic compounds (PACs) in 9 categories were successfully identified in fine particulate matter by gas chromatography high resolution mass spectrometry. Using mass spectra and retention indexes predicted by in silico tools as complementary information, the scope of chemical identification was efficiently expanded by 27%. In addition, quantitative structure-activity relationship models provided toxicity data for over 70% of PACs, facilitating a comprehensive health risk assessment. On the basis of extensive identification, the cumulative noncarcinogenic risk of PACs warranted attention. Meanwhile, the carcinogenic risk of 53 individual analogues was noteworthy. These findings suggest that there is a pressing need for an updated list of priority PACs for routine monitoring and toxicological research since legacy polycyclic aromatic hydrocarbons (PAHs) contributed modestly to the overall abundance (18%) and carcinogenic risk (8%). A toxicological priority index approach was applied for relative chemical ranking considering the environmental occurrence, fate, toxicity, and analytical availability. A list of 39 priority analogues was compiled, which predominantly consisted of high-molecular-weight PAHs and alkyl derivatives. These priority PACs further enhanced source interpretation, and the highest carcinogenic risk was attributed to coal combustion.

Degree of compaction, aeration, and soil water retention indices of a sugarcane field without soil disturbance after initial tillage

Soil compaction after initial soil tillage for crop establishment has been a major problem in crop fields because of its deleterious effects on soil functioning and crop performance. Therefore, the study aimed to determine the degree of compaction, soil air capacity, near-surface optimum ratios, and water retention characteristics in a sandy loam. Dystrophic Paleudalf initially under different tillage methods for sugarcane crop but without tillage for two seasons in southern Brazil. Initial soil tillage systems consisted of no-tillage (NT), compacted no-tillage (NTC), conventional tillage, and chiseling of no-tillage (Ch). Disturbed and undisturbed soil was sampled from 0 to 10, 10 to 20, 20 to 40, and 40 to 60 cm layers to determine degree of compaction, air capacity, near-surface optimum ratios, soil water retention characteristics, and soil physical quality index S. Initially, NT treatment had the significantly ( p &lt; 0.05) lowest degree of compaction (87%), highest soil air capacity (0.104 cm3 cm−3), air capacity/total porosity ratio (0.261), and better water retention characteristics in the surface layer. Over time, Ch had improved the structure of the subsurface soil layers with the lowest degree of compaction (≈88%) and highest air capacity (≈0.140 cm3 cm−3), while the measured indices were poor in NTC. Irrespective of tillage, the surface layer showed resilience during the years without soil disturbance with low degree of compaction, increased water retention, and air capacity. NT could be a good soil management option for sugarcane production, while mechanical chiseling is advocated for ameliorating compacted soils.

Comparison of untargeted gas chromatography-mass spectrometry analysis algorithms with implications to the interpretation and putative identification of volatile aroma compositions

The aroma profiling process requires the identification of the volatile compounds in a sample or its headspace. Typically, the identification of compounds relies on automated feature finding and matching algorithms to (putatively) identify and report compounds based on retention index and mass spectra matching against a compound library. We investigated the use of five different workflows and proposed three metrics (target accuracy A, identification percentage I, uniqueness U) to quantify their impact on generated aroma profiles of a mixture of fragrance standards and a commercial grade essential oil. All workflows accurately identified target compounds (100% in standards, >90% in samples) and reported similar compound identities for major GC–MS features, but beyond that could differ by up to 40–50%. Despite the variances, different workflows did not report conflicting compound identities. Aroma compositions primarily contained unreported or extra (putatively) identified compounds due to variations in mass spectral elucidations within the various workflows. Considering these differences, we show how the proposed metrics, I and U, could be modified to help the analyst interpret and evaluate reported volatile aroma compositions of unknown materials.

Porous Starch-inulin Loaded Quercetin Microcapsules: Characterization, Antioxidant Activity, in-vitro Release, and Storage Stability

Quercetin (Q) has many potential health benefits, but its low stability limits its use in functional foods and pharmaceuticals. The low stability of quercetin is a challenge that needs to be addressed to fully realize its therapeutic potential. The purpose of this study was therefore to design a proper carrier based on porous starch (PS) and inulin (IN) in order to improve the stability of Q. The scanning electron microscopy (SEM) images denoted that the Q molecules were adsorbed in the PS pores and partially adhered to the surface of the granules. Both types of the wall material could remarkably enhance the protection of Q against thermal and light degradation. The retention index of Q under different environmental conditions was higher for the PS:IN-Q than PS-Q. The results of Fourier transform infrared spectroscopy (FT-IR) revealed that Q interacted with the wall materials through non-covalent bonds. X-ray diffraction (XRD) also confirmed the encapsulation of Q in the wall materials. The bonding between Q and the hydrogen groups of starch compacted the crystalline regions and increased the relative crystallinity in PS-Q and PS:IN-Q. The DPPH and ABTS scavenging activities of the microcapsules containing the PS and IN were higher than those of free Q. Examination of the in-vitro release profile indicated that the Q release rate was lower from the PS:IN-Q microcapsules (21.6%) than from the PS-Q ones (33.7%). Our findings highlight the significant potential of this novel biopolymer mixture (PS/IN) as a promising wall material for the protection and delivery of bioactive compounds.

Detection of Liver Lesions in Colorectal Cancer Patients Using 18F-FDG PET/CT Dual-Time-Point Scan Imaging.

The aim of this study was to evaluate the diagnostic performance of dual-time-point fluorine-18-fluorodeoxyglucose positron emission computed tomography/computed tomography (18F-FDG PET/CT) compared to conventional early imaging for detecting colorectal liver metastases (CRLM) in colorectal cancer (CRC) patients. One hundred twenty-four consecutive CRC patients underwent dual-time-point imaging scans on a retrospective basis. Histopathological confirmation and/or clinical follow-up were accepted as the gold standard. Standard uptake values (SUV), signal-to-noise ratio (SNR), retention index (RI), tumor-to-normal liver ratio (TNR), and lesion sizes were measured for early and delayed PET scans. The diagnostic performance of early and delayed images was calculated on a per-patient basis and compared using McNemar's test. Among the 124 patients, 57 (46%) had CRLM, 6 (4.8%) had benign lesions, and 61 (49.2%) had no concerning lesions detected. Smaller CRLM lesions (<5 cm3) showed significantly higher uptake in the delayed scans relative to early imaging (p < 0.001). The SUV and TNR increased significantly in delayed imaging of all metastatic lesions (p < 0.001). The retention index of all CRLM was high (40.8%), especially for small lesions (54.8%). A total of 177 lesions in delayed images and 124 in standard early images were identified. In a per-patient analysis, delayed imaging had significantly higher sensitivity (100% vs. 87.7%) and specificity (91.0% vs. 94.0%) compared to early imaging (p-value = 0.04). The detection of liver lesions using dual-time-point PET/CT scan improves the sensitivity and specificity for the detection of colorectal liver metastasis.

Retention characteristics, saturated vapor pressure and vaporization enthalpy of mesityl oxide ethers of linear alcohols C1–C5

Ethers of mesityl oxide and linear alcohols C1-C5 have been synthesized.Retention characteristics were determined using the method of gas–liquid chromatography with a column with a non-polar phase in the temperature range of 373.2–463.2 K. Based on these characteristics, the values of the sorption enthalpies of ethers, saturated vapor pressures and enthalpies of vaporization were calculated. Dependences of retention indices on temperature, retention indices and sorption enthalpies on the number of carbon atoms in the molecule of the alcohol radical of ethers have a linear form. The values of excess enthalpies of mixing are estimated and the enthalpies of vaporization obtained in the work and calculated by the QSPR-method are compared.

DrugBank 6.0: the DrugBank Knowledgebase for 2024.

First released in 2006, DrugBank (https://go.drugbank.com) has grown to become the 'gold standard' knowledge resource for drug, drug-target and related pharmaceutical information. DrugBank is widely used across many diverse biomedical research and clinical applications, and averages more than 30 million views/year. Since its last update in 2018, we have been actively enhancing the quantity and quality of the drug data in this knowledgebase. In this latest release (DrugBank 6.0), the number of FDA approved drugs has grown from 2646 to 4563 (a 72% increase), the number of investigational drugs has grown from 3394 to 6231 (a 38% increase), the number of drug-drug interactions increased from 365 984 to 1 413 413 (a 300% increase), and the number of drug-food interactions expanded from 1195 to 2475 (a 200% increase). In addition to this notable expansion in database size, we have added thousands of new, colorful, richly annotated pathways depicting drug mechanisms and drug metabolism. Likewise, existing datasets have been significantly improved and expanded, by adding more information on drug indications, drug-drug interactions, drug-food interactions and many other relevant data types for 11891 drugs. We have also added experimental and predicted MS/MS spectra, 1D/2D-NMR spectra, CCS (collision cross section), RT (retention time)and RI (retention index) data for 9464 of DrugBank's 11710 small molecule drugs. These and other improvements should make DrugBank 6.0 even more useful to a much wider research audience ranging from medicinal chemists to metabolomics specialists to pharmacologists.

Novel SPECT/CT biomarker in transthyretin cardiac amyloidosis: correlation with myocardial amyloid load and cardiac structure and function

Abstract Background Single photon emission computed tomography/computed tomography (SPECT/CT) with determination of standardized uptake value (SUV) allows quantification of cardiac amyloid deposition. Purpose We aimed to investigate the relationship between quantitative cardiac tracer uptake determined by SPECT/CT and myocardial amyloid load, as well as cardiac structure and function in patients with transthyretin amyloid cardiomyopathy (ATTR-CM), and to identify nuclear imaging biomarkers for monitoring disease progression. Methods ATTR-CM patients underwent [99mTc]-radiolabeled diphosphono-1,2-propanodicarboxylic acid ([99mTc]-DPD) scintigraphy and SPECT/CT imaging (n=40) with determination of SUV, as well as cardiac magnetic resonance imaging (CMR, n=25) and transthoracic echocardiography (TTE, n=40). Results We observed significant correlations (r, Pearson's correlation coefficient) between SUV retention index and myocardial amyloid load [CMR extracellular volume (ECV): r=0.565, p=0.004, Figure 1A], cardiac structure [CMR interventricular septum: r=0.409, p=0.042, Figure 1B; CMR left ventricular mass index: r=0.508, p=0.010, Figure 1C], longitudinal cardiac function [TTE left ventricular global longitudinal strain (LV GLS): r=0.531, p=0.003, Figure 1D; TTE right ventricular free wall longitudinal strain: r=0.470, p=0.024, Figure 1E; TTE left atrial reservoir strain (LASr): r=-0.434, p=0.038, Figure 1F] and cardiac biomarkers [N-terminal prohormone of brain natriuretic peptide (NT-proBNP): r=0.475, p=0.004; high-sensitive troponin T (hs-TnT): r=0.358, p=0.027]. ATTR-CM patients were divided into two cohorts based on the median (4.32 mg/dL) of SUV retention index (low SUV uptake cohort: ≤4.32 mg/dL, n=20; high SUV uptake cohort: &amp;gt;4.32 mg/dL, n=20). We observed significant between-cohort differences with respect to LV ejection fraction (low SUV uptake: 51.8% vs. high SUV uptake: 46.2%, p=0.045), LV GLS (-14.5% vs. -11.1%, p=0.001), LASr (11.6% vs. 7.1%, p=0.023), NT-proBNP (1300 pg/mL vs. 2786 pg/mL, p&amp;lt;0.001), hs-TnT (42.9 ng/L vs. 62.2 ng/L, p=0.016) and 6-min walk distance (440.1 m vs. 330.1 m, p=0.022). Conclusions Using quantitative SPECT/CT imaging, we demonstrated that SUV retention index correlates with myocardial amyloid load, cardiac structure and function, and cardiac biomarkers. Our data suggest that quantitative SPECT/CT imaging with determination of SUV retention index may be a valid tool to monitor disease progression in ATTR-CM patients.Figure 1

Multi-modal Analysis of Water Milk Consumption Preferences and Influencing Factors——Based on Shanghai's Generation Z Crowd

This study aims to analyze the consumption preference and influencing factors of Buffalo Milk among Shanghai's Generation Z population, to provide marketing strategy references for dairy companies, and to promote the healthy development of Shanghai's Buffalo Milk market.In this paper, we first take the Generation Z population as the main body through network survey and literature survey, and select potential consumers who will buy buffalo milk from them, and then recover the questionnaires to conduct follow-up surveys, organize and analyze the existing buffalo milk industry data, and derive the overall development of Shanghai's Generation Z buffalo milk market, and compare the customer's loyalty to the brand by using the retention index in order to explore the brand equity of each brand. The brand equity of each brand is explored by utilizing the retention index to compare customer loyalty. Secondly, we collect basic data on buffalo milk consumption of Generation Z through online questionnaire survey based on K-Means clustering algorithm for feature extraction, and use word cloud to draw user profiles to find out the consumption preference of buffalo milk crowd. Then, the logistic model is used to explore the significant influencing factors that affect consumers' purchase of buffalo milk. Finally, we provide reasonable and effective suggestions for the "broken circle" problem of buffalo milk.

QSPR models for predicting the Kovats retention indices of synthetic ester derivatives based on pyrethrin essential oil

ABSTRACT In this study, the chromatographic characteristics of 100 different pyrethroids including ester derivatives of cyclopropanecarboxylic acids were analyzed by measuring their logarithmic kovats retention index (log KRI) using a quantitative structure-retention relationship (QSRR). The log KRI of the studied pyrethroids were modeled by genetic algorithm-structure retention relationships (GA-QSRR) based on linear and nonlinear regression models. The descriptors such as HNar, H0v, and H5p, which express the GETAWAY (geometry, topology, and atom-weights assembly) compound descriptors, have a reasonable correlation with the log KRI. We assessed the predictive strength of the BP-ANN model and demonstrated the potential of the model using various statistical parameters. The statistical parameters such as Q2F1, Q2F2, Q2F3 , AAD, RMSE and CCC were used to evaluate the predictive ability of the BP-ANN model. In predicting the log KRI of pyrethroids, the results indicated that the BP-ANN model is more reliable and accurate than the BW-MLR model.

Characterization and Evaluation of the In Vitro Antioxidant, α-Glucosidase Inhibitory Activities of Camellia longii Orel and Luu. (Theaceae) Flower Essential Oil and Extracts From Vietnam

Objective/Background: Camellia longii Orel and Luu was discovered for the first time in Cat Tien National Park of Lam Dong Province, Southern Vietnam, was determined as a new species. To the best of our knowledge, this is the first report on the phytochemical and bioactivity of this species. Methods: The chemical profile of essential oil (EO) prepared from C. longii flowers was determined by GC/MS analysis and comparison of the recorded retention indices and the corresponding literature values. The total phenolic and flavonoid contents in different flower extracts were estimated by Folin-Ciocalteu and aluminum chloride methods with a spectrophotometer, respectively. The antioxidant activities of the extracts were determined by various bioassays, including DPPH free radical scavenging, ferric reducing power, and cupric reducing antioxidant capacity. The α-glucosidase inhibitory activity of the extracts was evaluated using p-nitrophenyl α-D-glucopyranoside solution as a substrate and acarbose as the positive control. Results: Fifty-seven compounds were identified from the EO of C. longii flowers. Among these, the main components were α-eudesmol (16.1%), followed by ( E)-nerolidol (13.0%), β-eudesmol (8.9%), τ-cadinol (6.5%), and γ-eudesmol (5.8%). The total phenolic and flavonoid contents were found high in ethyl acetate, n-butanol, and ethanol extracts (206.8-378.6 mg gallic acid equivalents/g crude extract and 298.5-390.3 mg rutin equivalents/g crude extract, respectively). These extracts were shown to possess potent antioxidant activities in the examined bioassays. As for the α-glucosidase inhibitory assay, the ethyl acetate, butanol, and ethanol extracts were shown to be more potent than acarbose with IC50 values of 2.16 ± 0.04, 1.95 ± 0.05, and 1.53 ± 0.04 μg/mL, respectively. Conclusion: The findings first provide the phytochemical profiles of Camellia longii Orel and Luu and its bioactivities, indicating moderate potentials in antioxidant activity and strong α-glucosidase inhibition.