RESUMO
Analyzing the spatiotemporal evolution of urban land use and habitat quality can reveal the correlation between land use and habitat quality, aiding in rational urban land policies and high-quality ecological environment development. This study was based on land use transition matrices and an Intensity-Migration ï¼IMï¼ model to analyze the changes in land use in Harbin from 2000 to 2020. It combined the PLUS model to explore the driving factors of land use expansion for various land types and predicted land use scenarios for 2030 under natural development, ecological protection, farmland protection, and urban development scenarios. Finally, the InVEST model was used to complete the habitat quality analysis. The results indicatedï¼ â The dominant land use types in Harbin were cropland, forest land, and grassland. From 2000 to 2020, there was a significant tendency of conversion into grassland, cropland, forest land, and artificial surfaces, with noticeable changes in land use intensity. Water bodies, bare land, and wetland types showed less conversion and tended to be restrictive. â¡ Elevation was the primary factor influencing the expansion of grassland, cropland, forest land, bare land, wetland, and water bodies. Socioeconomic factors were the main factor affecting the expansion of artificial surfaces. ⢠Simulation of land use types in Harbin for 2030 under the four scenarios showed an increase in forest land area and a decrease in grassland area, with insignificant changes in wetland, water bodies, and bare land areas. Except for in the ecological protection scenario, the area of artificial surfaces increased, whereas cropland decreased. ⣠Overall, habitat quality in Harbin improved from 2000 to 2020. ⤠In 2030, the spatial pattern of habitat quality in Harbin remained consistent across all scenarios, showing an overall improvement in habitat quality. Under the ecological protection scenario, areas with low and medium habitat quality decreased, whereas areas with higher habitat quality increased, indicating a relatively significant improvement in habitat quality. The research results provide a scientific basis and insights for the development of ecological civilization and urban planning and construction in Harbin.
RESUMO
Photodegradation kinetics of fleroxacin were investigated in different injections. Five commercial formulations were analyzed before and after irradiation by determining residual volumes of fleroxacin with high-pressure liquid chromatography (HPLC), and different decomposition functions and models were obtained. Concentration levels of fleroxacin in injections caused the differences in photodegradation kinetics instead of ingredients. Influences of different pH values and presence of NaCl on photodegradation of fleroxacin were observed. Low pH value decreased the efficacy of photolysis and enhanced photostability of fleroxacin injections. Tentative structure of a new degradation product afforded was proposed. An acute toxicity assay using the bioluminescent bacterium Q67 was performed for fleroxacin injections after exposure to light. The research proved that fleroxacin was more photolabile in dilute injection, and acute toxicity of dilute injection increased more rapidly than that of concentrated injection during irradiation.
Assuntos
Antibacterianos/efeitos da radiação , Fleroxacino/efeitos da radiação , Antibacterianos/administração & dosagem , Antibacterianos/química , Antibacterianos/toxicidade , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Formas de Dosagem , Estabilidade de Medicamentos , Fleroxacino/administração & dosagem , Fleroxacino/química , Fleroxacino/toxicidade , Concentração de Íons de Hidrogênio , Injeções , Cinética , Medições Luminescentes , Estrutura Molecular , Fotólise , Cloreto de Sódio/química , Tecnologia Farmacêutica/métodos , Vibrio/efeitos dos fármacosRESUMO
Most herbal medicines could be processed to fulfill the different requirements of therapy. The purpose of this study was to discriminate between raw and processed Dipsacus asperoides, a common traditional Chinese medicine, based on their near infrared (NIR) spectra. Least squares-support vector machine (LS-SVM) and random forests (RF) were employed for full-spectrum classification. Three types of kernels, including linear kernel, polynomial kernel and radial basis function kernel (RBF), were checked for optimization of LS-SVM model. For comparison, a linear discriminant analysis (LDA) model was performed for classification, and the successive projections algorithm (SPA) was executed prior to building an LDA model to choose an appropriate subset of wavelengths. The three methods were applied to a dataset containing 40 raw herbs and 40 corresponding processed herbs. We ran 50 runs of 10-fold cross validation to evaluate the model's efficiency. The performance of the LS-SVM with RBF kernel (RBF LS-SVM) was better than the other two kernels. The RF, RBF LS-SVM and SPA-LDA successfully classified all test samples. The mean error rates for the 50 runs of 10-fold cross validation were 1.35% for RBF LS-SVM, 2.87% for RF, and 2.50% for SPA-LDA. The best classification results were obtained by using LS-SVM with RBF kernel, while RF was fast in the training and making predictions.
Assuntos
Dipsacaceae/química , Medicamentos de Ervas Chinesas/química , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Dipsacaceae/classificação , Análise Discriminante , Medicamentos de Ervas Chinesas/classificação , Análise dos Mínimos Quadrados , Modelos Estatísticos , Sensibilidade e Especificidade , Máquina de Vetores de SuporteRESUMO
Photodegradation of fleroxacin is investigated in different injections and solutions. After UV irradiation, fleroxacin was degraded to afford two major products in large-volume injection (specification, 200 mg:100 ml), while degraded to afford another major product in small-volume injection (specification, 200 mg:2 ml). The photodegradation products were detected and isolated by reversed-phase HPLC. Based on the spectral data (FT-IR, MS(n), TOF-MS, (1)H/(13)C, DEPT, and 2D NMR), the structures of these products were: 8-fluoro-9-(4-methyl-piperazin-1-yl)-6-oxo-2,3-dihydro-6H-1-oxa-3a-aza-phenalene-5-carboxylic acid (impurity-I); 6-fluoro-1-(2-fluoro-ethyl)-7-(2-methylamino-ethylamino)-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (impurity-II); and 6,8-difluoro-1-(2-fluoro-ethyl)-7-(2-methylamino-ethylamino)-4-oxo-1,4-dihydro-quinoline-3-carboxylic acid (impurity-III), respectively. Different photodegradation pathways of fleroxacin were proposed, which led to the different stability characteristics of fleroxacin in the injections. The fluorine atom at C8 is more photolabile in dilute injection, so defluorination and cyclization reactions are prone to take place, whereas photo irradiation only cause ring-opening oxidation reaction of piperazine side chain in concentrated injection.
Assuntos
Anti-Infecciosos , Fleroxacino , Fotólise/efeitos da radiação , Anti-Infecciosos/química , Anti-Infecciosos/efeitos da radiação , Cromatografia de Fase Reversa , Ciclização/efeitos da radiação , Estabilidade de Medicamentos , Fleroxacino/química , Fleroxacino/efeitos da radiação , Compostos Heterocíclicos com 3 Anéis/química , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Oxirredução/efeitos da radiação , Fotoquímica , Quinolinas/química , Soluções , Espectroscopia de Infravermelho com Transformada de Fourier , Raios UltravioletaRESUMO
The present work is to find the optimum condition for fluorescence resonance energy transfer between CdTe QDs (donor) and rhodamine B (acceptor) and form a new method to detect copper in Flos Lonicerae Japonicae. In tris-HCl buffer solution at pH 6.00, by employing cetyltrimethylammonium bromide, Cu2+ can quench the fluorescence intensity of BRB and detect the concentration of Cu2+. Results show that a linear relationship could be established between the quenched fluorescence intensity of RhB and the concentration of Cu2+ in the range of 1.3 x 10(-4) - 3.1 x 10(-2) microg x mL(-1), the limit of detection was 4.6 x 10(-5) microg x mL(-1) (r = 0.996), RSD and the average recovery was 3.5% and 103.4% (n = 5), respectively. It is concluded that the developed method was proved to be feasible to detect copper in Flos Lonicerae Japonicae.
Assuntos
Cobre/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Lonicera/química , Pontos Quânticos , RodaminasRESUMO
Asperosaponin VI (also named akebia saponin D) is a typical bioactive triterpenoid saponin isolated from the rhizome of Dipsacus asper Wall (Dipsacaceae). In this work, a sensitive high-performance liquid chromatography-electrospray ionization-mass spectrometry (HPLC-ESI-MS) assay has been established for determination of asperosaponin VI in rat plasma. With losartan as the internal standard (IS), plasma samples were prepared by protein precipitation with methanol. Chromatographic separation was performed on a C(18) column with a mobile phase of 10 mm ammonium acetate buffer containing 0.05% formic acid-methanol (32 : 68, v/v). The analysis was performed on an ESI in the selected ion monitoring mode using target ions at m/z 951.4 for asperosaponin VI and m/z 423.2 for the IS. The calibration curve was linear over the range 3-1000 ng/mL and the lower limit of quantification was 3.0 ng/mL. The intra- and inter-assay variability values were less than 9.5 and 7.8%, respectively. The accuracies determined at the concentrations of 3.0, 100.0, 300.0 and 1000 ng/mL for asperosaponin VI were within +/-15.0%. The validated method was successfully applied to a pharmacokinetic study in rats after oral administration of asperosaponin VI.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Saponinas/sangue , Espectrometria de Massas por Ionização por Electrospray/métodos , Animais , Calibragem , Dipsacaceae/química , Limite de Detecção , Ratos , Saponinas/isolamento & purificaçãoRESUMO
According to Traditional Chinese Medicine, Alzheimer's disease (AD) is regarded as senile dementia, and the etiopathogenesis lies in kidney deficiency during aging. Dipsacus asper Wall (DAW), a well-known traditional Chinese medicine for enhancing kidney activity, may possess the therapeutic effects against AD. Our objectives were to investigate the protective effects of DAW against the amyloid-beta peptide (A beta)-induced cytotoxicity and explore its major active components. Injury of PC 12 cells mediated by A beta(25-35) was adopted to assess the cytoprotective effects of DAW aqueous extract and various fractions. Salvianolic acid B, a polyphenol compound isolated from Salvia miltiorrhiza, was employed as a positive control agent due to its markedly protective effect against neurotoxicity of amyloid beta. Five chemical fractions (i.e. alkaloids, essential oil, saponins, iridoid glucoside and polysaccharides) were prepared for activity test and analyzed by HPLC for active components identification. In addition, Akebia saponin D (the most important compound in DAW saponins) and hederagenin (the mother nucleus of akebia saponin D) were prepared for testing of their activity. DAW water extract, saponins fraction and akebia saponin D had the neuroprotective capacity to antagonize A beta(25-35)-induced cytotoxicity in PC 12 cells. In contrast, other fractions and hederagenin had no cytoprotective action. This research suggests that DAW may represent a potential treatment strategy for AD and akebia saponin D is one of its active components.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/antagonistas & inibidores , Citoproteção , Medicamentos de Ervas Chinesas/farmacologia , Saponinas/farmacologia , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Cálcio/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Dipsacaceae/química , L-Lactato Desidrogenase/efeitos dos fármacos , L-Lactato Desidrogenase/metabolismo , Ácido Oleanólico/análogos & derivados , Ácido Oleanólico/farmacologia , Células PC12 , RatosRESUMO
Fluorescence spectra and fluorescence quantum yield of TiO2 nanocrystals were studied. Using tetra n-butyl titanate as a starting material, a facile alcohothermal technique was used to synthesize TiO2 nanocrystals. As can be seen from the transmittance electron microscopy (TEM) image, TiO2 nanocrystals with a relatively uniform particle size distribution of < 10 nm are present in the transparent sol. The transparent sol presents a strong stable fluorescence emission with a maximum at 450 nm, which is greatly dependent on the size quantization effects, defect energy level and the surface state of TiO2 nanocrystals. The quantum yield (gamma) of TiO2 was determined by the relative comparison procedure, using freshly prepared analytical purity quinine sulfate in 0.05 mol x L(-1) H2SO4 as a relative quantum yield standard. The emission quantum yield of TiO2 nanocrystals prepared in alcoholic media was calculated to be about 0.20 at wavelengths ranging from 330 to 370 nm, which was much higher than the values reported in previous works. So, it is supposed that nano-TiO2 will be applied as a potential quantum dots fluorescence probe in biological analysis.
Assuntos
Álcoois/química , Nanopartículas/química , Temperatura , Titânio/química , Absorção , Quinina/química , Espectrometria de Fluorescência , Difração de Raios XRESUMO
The pH-sensitive cadmium telluride (CdTe) quantum dots (QDs) were used as proton probes for tiopronin determination. Based on the fluorescence quenching of CdTe QDs caused by tiopronin, a simple, rapid and specific quantitative method was proposed. Under the optimal conditions, the calibration plot of ln(F(0)/F) with concentration of tiopronin was linear in the range of 0.15-20 microg mL(-1)(0.92-122.5 micromol L(-1)) with correlation coefficient of 0.998. The limit of detection (LOD) (3sigma/k) was 0.15 microg mL(-1)(0.92 micromol mL(-1)). The content of tiopronin in pharmaceutical tablet was determined by the proposed method and the result agreed with that obtained from the oxidation-reduction titration method and the claimed value.
Assuntos
Compostos de Cádmio/química , Sondas Moleculares , Pontos Quânticos , Telúrio/química , Tiopronina/análise , Calibragem , Microscopia Eletrônica de Transmissão , Oxirredução , Sensibilidade e Especificidade , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
OBJECTIVE: To propose an algorithm of the similarity between UV-spectra for controlling the quality of Chinese medical injection. METHOD: The similarity is calculated base on the data of two UV-spectrum curves, thus the sample quality is evaluated according to the average value of the similarity of the UV-spectra between sample with each of standard samples; the proposed algorithm of the similarity is compared with cosine of vectorial angle and relative coefficient; the proposed method for quality evaluation of traditional Chinese injection is discussed with the method according to the chromatographic fingerprint similarity. RESULT: The calculated similarity with the proposed method can be sensitive to show the difference between UV-spectra. This proposed method for quality evaluation was applied for assessing quality of 14 batches of Xiangdan injection and the results well coincident with sample quality. CONCLUSION: The proposed method can be used to evaluate the quality of the Chinese medical injection according to the similarity of two UV-spectrum curves.
Assuntos
Algoritmos , Medicamentos de Ervas Chinesas/química , Espectrofotometria Ultravioleta/métodos , Cromatografia Líquida de Alta Pressão/métodos , Dalbergia/química , Combinação de Medicamentos , Medicamentos de Ervas Chinesas/administração & dosagem , Medicamentos de Ervas Chinesas/normas , Injeções , Plantas Medicinais/química , Controle de Qualidade , Salvia miltiorrhiza/químicaRESUMO
OBJECTIVE: To study the relationship between copper and organic components, total flavonoids of Astragalus (TFA), total saponins of Astragalus (TSA) and total polysaccharide of Astragalus (TPA). METHOD: TFA, TSA and TPA were extracted from Astragalus roots using different organic solvents, and determined by colorimetry. The concentration of copper in extracts was determined by graphite furnace atomic absorption spectrometry (GFAAS). RESULT: Copper was found in TFA, TPA and TSA, and its concentration in TFA and TPA was higher; the content of copper was correlated significantly to that of TFA and TPA (r1(2) = 0.754 8, F1 = 57.202, P < 0.01 and r2(2) = 0.499, F2 = 21.906, P < 0.01), while not to that of TSA ( r3(2) = 0.0026, F3 = 0.041, P > 0.1). CONCLUSION: Correlation analysis could reveal the relationship of copper with organic components in Astragalus roots; contents and structure characteristics of organic components might be important factors influencing the distribution of copper in Astragalus roots.
Assuntos
Astragalus propinquus/química , Cobre/análise , Flavonoides/isolamento & purificação , Polissacarídeos/isolamento & purificação , Saponinas/isolamento & purificação , Flavonoides/química , Estrutura Molecular , Raízes de Plantas/química , Plantas Medicinais/química , Polissacarídeos/química , Saponinas/químicaRESUMO
In the present paper, a fluorescence method was used to study at different pH the fluorescence quenching of bovine serum albumin (BSA) by its interaction with balofloxacin (BLFX). The interaction association constants of BSA and BLFX were determined from a double reciprocal line Weaver-Burk plot. According to the Forster dipole-dipole energy transfer, the distance to be measured between the BLFX and tryptophane is 5.09 nm. From thermodynamical coordination it can be judged that the binding power between BLFX and BSA is electrostatic effect. The effect of BLFX on the conformation of BSA was also analyzed by using synchronous fluorescence spectroscopy.
Assuntos
Fluorescência , Fluoroquinolonas/química , Soroalbumina Bovina/química , Animais , Bovinos , Transferência de Energia , Fluoroquinolonas/metabolismo , Cinética , Ligação Proteica , Soroalbumina Bovina/metabolismo , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Eletricidade Estática , TermodinâmicaRESUMO
A sequential procedure for the method of development of fingerprints based on a uniform design approach has been described in this paper. The sequential uniform design is used to reach the global optimum for a separation. The procedure is illustrated through developing the fingerprint of a Ginkgo biloba extract by capillary electrophoresis (CE) with diode array detection (DAD). The local overlap index (LOVI) is proposed as a criterion to evaluate the separation quality of two-dimensional hyphenated data in the optimization process. The successful application of the described techniques, including a sequential procedure, the CE-DAD hyphenated method and the LOVI criterion, shows their practicality in the fingerprint development of herbal medicines. However, some critical remarks on their use can also be made.
Assuntos
Eletroforese Capilar/métodos , Ginkgo biloba/química , Soluções Tampão , Extratos Vegetais/químicaRESUMO
A simple, sensitive and selective liquid chromatography coupled with electrospray ionization mass spectrometry (LC/ESI/MS) method for determination of limonin (LM) in rat plasma has been developed and validated. The method had advantages of a single liquid-liquid extraction with ether and high sensitivity. Analyses were conducted at a flow rate of 0.2 ml/min by a gradient elution. The detection utilized selected ion monitoring in the negative ion mode at m/z 460.00 and 423.15 for the deprotonated molecular ions of LM and the internal standard, respectively. The quantitation limit for LM in rat plasma was 1.0 ng/ml. The linearity was also excellent over the concentration range of 1.9-500 ng/ml of LM. The intra- and inter-day precision (relative standard deviation (R.S.D.%)) was lower than 10% and accuracy ranged from 90 to 110%, showing a good reproducibility. This developed method was successfully applied to analysis of LM in biological fluids.
Assuntos
Limoninas/sangue , Animais , Calibragem , Cromatografia Líquida , Feminino , Congelamento , Masculino , Controle de Qualidade , Ratos , Ratos Sprague-Dawley , Padrões de Referência , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
A four-step development, optimization and validation strategy for high-performance liquid chromatography (HPLC) fingerprints of Ginkgo biloba extract is described. A suitable chromatographic system was selected first. The following step was performing a screening design to select important parameters. After selecting some controllable parameters and their range to further optimize, gradient optimization with uniform design was done. At last, method validation including determination of injection precision, repeatability, and a sample stability test, was performed. Through this effective and integrated four-step method, a feasible and reliable HPLC fingerprint to identify and assess the Ginkgo biloba quality can easily be established using a linear gradient elution with acetonitrile/0.1% phosphoric acid (from 14/86 to 30/70, v/v, in 40 min) as mobile phase, a column temperature of 30 degrees C and a detection wavelength of 350 nm. The strategy can also be applied for the development of fingerprints in the quality control of other herbal medicines.