Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Chem Commun (Camb) ; 59(86): 12923-12926, 2023 Oct 26.
Artículo en Inglés | MEDLINE | ID: mdl-37823279

RESUMEN

We demonstrate that a tripodal hexaurea receptor can selectively bind PO43- anions via 12 hydrogen bonds with up to 3.8 × 106 M-1 binding affinity in DMSO, which is 38-fold stronger than SO42-. This receptor facilitates the extraction of PO43- from strongly basic aqueous solutions into chloroform using liquid-liquid extraction, followed by its release as the H2PO4- anion into an acidic solution. This pH-dependent phosphate extraction successfully enables selective separation of phosphate and sulfate anions.

2.
J Org Chem ; 88(19): 14004-14011, 2023 Oct 06.
Artículo en Inglés | MEDLINE | ID: mdl-37682987

RESUMEN

Improving the detonation performance of tetranitromethane (TNM) by introducing energetic moieties is an intriguing area in the field of energetic materials. Incorporation of a mono nitrogen-rich skeleton into TNM usually results in unsatisfactory detonation performance. Now, we reported the design and synthesis of an advanced TNM-like molecule (3) containing nitrogen-rich triazole and nitro-triazinane moieties. In addition, two of its analogues (4 and 5) were also obtained. Taking advantage of the positive heat of formation brought by triazole and triazinane rings and high-density properties donated by many nitro groups, 3 shows promising heat of detonation (Q = 5859 kJ kg-1), which is 2.8 times of TNM and higher than most of its mono ring-modified derivatives (Q: 2076 to 5594 kJ kg-1). The detonation velocity and detonation pressure of 3 (Dv = 8964 m s-1 and P = 35.7 GPa) are competitive with those of RDX (Q = 5763 kJ kg-1, Dv = 8782 m s-1, and P = 34.7 GPa). Structural modification by using triazole and nitro-triazinane rings may be helpful in exploring more TNM derivatives and other types of high-performance explosives.

3.
Sci Total Environ ; 902: 165914, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-37524183

RESUMEN

Many studies have focused on the impact of nitrogen deposition on plants, but due to technical limitations, research on the responses of forest canopy to manipulated nitrogen deposition is relatively scarce. Based on a canopy nitrogen addition (CN) platform, this study used laboratory analysis and unmanned aerial vehicle (UAV) observations to assess the impact of CN on the canopy traits of dominant tree species (Engelhardia roxburghiana, Schima superba, and Castanea henryi) in an evergreen broad-leaved forest in China. The results showed that nitrogen application at 25 kg N ha-1 y-1 (CN25) and 50 kg N ha-1 y-1 (CN50) significantly increased the actual net photosynthetic rate (An) of all the three tree species. CN25 significantly increased superoxide dismutase (SOD), catalase (CAT), and ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) activities in C. henryi. CN50 significantly increased the leaf area of all the three tree species and significantly reduced the leaf thickness of C. henryi, and significantly increased the POD and Rubisco activities in S. superba and C. henryi. CN significantly changed the number of forest gaps, but did not significantly change the area of forest gaps within the sample plots. CN25 significantly decreased the vertical projection area but increased the canopy flowering coverage of S. superba in dominant directions. CN25 and CN50 significantly increased the flowering coverage of C. henryi in favorable directions. It is found that under long-term (10-year) nitrogen addition, the balance between carbon fixation and antioxidant defense functions of E. roxburghiana may be broken down, but the carbon assimilation, antioxidant capacity and reproduction potential of S. superba and C. henryi may be well coordinated, which will have a potential impact on the species composition and ecological functions of the evergreen broad-leaved forest. This study may also provide scientific basis for forest management in the context of enhanced atmospheric nitrogen deposition.


Asunto(s)
Nitrógeno , Árboles , Antioxidantes , Ribulosa-Bifosfato Carboxilasa , Bosques , Hojas de la Planta , China
4.
Spectrochim Acta A Mol Biomol Spectrosc ; 301: 122952, 2023 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-37270976

RESUMEN

The preparation of diclofenac sodium spheres by fluidized bed is a common production mode for the pharmaceutical preparations at present, but the critical material attributes in the production process is mostly analyzed off-line, which is time-consuming and laborious, and the analysis results lag behind. In this paper, the real-time in-line prediction of drug loading of diclofenac sodium and the release rate during the coating process was realized by using near infrared spectroscopy. For the best near infrared spectroscopy (NIRS) model of drug loading, R2cv, R2p, RMSECV, RMSEP were 0.9874, 0.9973, 0.002549 mg/g, 0.001515 mg/g respectively. For the best NIRS model of three release time points, the R2cv, R2p, RMSECV and RMSEP were 0.9755, 0.9823, 3.233%, 4.500%; 0.9358, 0.9965, 2.598%, 0.7939% and 0.9867, 0.9927, 0.4085%, 0.4726% respectively. And the analytical ability of these model was verified. The organic combination of these two parts of work constituted an important basis for ensuring the safety and effectiveness of diclofenac sodium spheres from the perspective of production process.


Asunto(s)
Diclofenaco , Espectroscopía Infrarroja Corta , Espectroscopía Infrarroja Corta/métodos , Diclofenaco/química , Análisis de los Mínimos Cuadrados
5.
Molecules ; 28(1)2023 Jan 03.
Artículo en Inglés | MEDLINE | ID: mdl-36615595

RESUMEN

Given the labor-consuming nature of model establishment, model transfer has become a considerable topic in the study of near-infrared (NIR) spectroscopy. Recently, many new algorithms have been proposed for the model transfer of spectra collected by the same types of instruments under different situations. However, in a practical scenario, we need to deal with model transfer between different types of instruments. To expand model applicability, we must develop a method that could transfer spectra acquired from different types of NIR spectrometers with different wavenumbers or absorbance. Therefore, in our study, we propose a new methodology based on improved principal component analysis (IPCA) for calibration transfer between different types of spectrometers. We adopted three datasets for method evaluation, including public pharmaceutical tablets (dataset 1), corn data (dataset 2), and the spectra of eight batches of samples acquired from the plasma ethanol precipitation process collected by FT-NIR and MicroNIR spectrometers (dataset 3). In the calibration transfer for public datasets, IPCA displayed comparable results with the classical calibration transfer method using piecewise direct standardization (PDS), indicating its obvious ability to transfer spectra collected from the same types of instruments. However, in the calibration transfer for dataset 3, our proposed IPCA method achieved a successful bi-transfer between the spectra acquired from the benchtop and micro-instruments with/without wavelength region selection. Furthermore, our proposed method enabled improvements in prediction ability rather than the degradation of the models built with original micro spectra. Therefore, our proposed method has no limitations on the spectrum for model transfer between different types of NIR instruments, thus allowing a wide application range, which could provide a supporting technology for the practical application of NIR spectroscopy.


Asunto(s)
Algoritmos , Calibración , Análisis de Componente Principal , Estándares de Referencia
6.
Curr Top Med Chem ; 23(14): 1340-1351, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36567287

RESUMEN

Drug polymorphism is an important factor affecting the drugs quality and clinical efficacy. Therefore, great attention should be paid to the crystal analysis of drugs with their researching and evaluating part. With the booming development of Raman spectroscopy in recent years, more and more crystal analysis investigations were based on vibrational spectroscopy. This review mainly discussed the qualitative and quantitative analysis of active pharmaceutical ingredients (API) and pharmaceutical preparation with Raman spectroscopy. On basis of the determination of the vibration mode of drug molecules and the analysis of their chemical structure, this method had the advantages of universal, non-destructive, fast determination, low samples and cost, etc. This review provides theoretical and technical support for crystal structure, which are worth popularizing. It is expected that it will be helpful to relevant government management institutions, pharmaceutical scientific research institutions and pharmaceutical manufacturers.


Asunto(s)
Espectrometría Raman , Espectrometría Raman/métodos , Preparaciones Farmacéuticas
7.
RSC Adv ; 12(35): 22492-22502, 2022 Aug 10.
Artículo en Inglés | MEDLINE | ID: mdl-36105952

RESUMEN

The catalytic activity of Au2Cu and AuCu samples for the electro-oxidation of CH3OH and HCOOH, together with their structure and micro-hardness were investigated using various techniques. The addition of Cu can improve the micro-hardness of samples, which is ascribed to the solid solution strengthening effect. The Schmid factor and low angle grain boundary fraction confirm the difference of plastic deformation ability for samples, being consistent with hardness results. The Au-Cu samples exhibit good bifunctional catalytic performance due to the synergistic effect between Au and Cu. In addition, the Au2Cu sample exhibits a higher catalytic activity than the AuCu sample, suggesting that appropriate preferred orientation plays a key role in the improvement of catalytic activities of Au based catalysts.

8.
Front Pharmacol ; 13: 899038, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35677447

RESUMEN

Xinkeshu tablets (XKST), a traditional Chinese patent medicine (CPM), have served in the clinical treatment of cardiovascular diseases (CVDs) for decades. However, its pharmacodyamic material basis was still unclear, and the holistic quality control has not been well established due to the lack of systematic research on the quality markers. In this experiment, the heart rate recovery rate of a zebrafish larva was used to evaluate the traditional pharmacological effect of XKST i.e., antiarrhythmic effect. The HPLC fingerprints of 16 batches of XKST samples were obtained, and antiarrhythmic components of XKST were identified by establishing the spectrum-effect relationship between HPLC fingerprints and heart rate recovery rate of zebrafish larva with orthogonal signal correction and partial least squares regression (OSC-PLSR) analysis. The anticardiovascular disease components of XKST were identified by mapping the targets related to CVDs in network pharmacology. The compounds of XKST absorbed and exposed in vivo were identified by ultra-high performance liquid chromatography Q-Exactive high-resolution mass spectrometry (UHPLC-Q-Exactive HRMS). Based on the earlier studies, combined with five principles for identifying quality markers and verified by a zebrafish arrhythmia model, danshensu, salvianolic acid A, salvianolic acid B, daidzein, and puerarin were identified as quality markers of XKST. In total, 16 batches of XKST samples were further quantified with the method established in this study. Our study laid the foundation for the quality control of XKST. The integrated strategy used in the study of XKST could be applied for the identification and quantification of quality markers of other CPMs as well.

9.
AAPS PharmSciTech ; 23(6): 174, 2022 Jun 24.
Artículo en Inglés | MEDLINE | ID: mdl-35739377

RESUMEN

The application of process analysis and control is essential to enhance process understanding and ensure output material quality. The present study focuses on the stability of the feedback control system for a fluidized bed granulation process. Two strategies of dynamic moisture control (DMC) and static moisture control (SMC) were established based on the in-line moisture value obtained from the near-infrared sensor and control algorithm. The performance of these strategies on quality consistency control was examined using process moisture similarity analysis and principal component analysis. The stable moisture control performance and low batch-to-batch variability indicated that the DMC method was significantly better than other granulation methods. In addition, the investigation of robustness further showed that the implemented DMC method was able to produce predetermined target moisture values by varying process parameters. This study provides an advanced and simple control method for fluidized bed granulation quality assurance.

10.
J Mol Neurosci ; 72(5): 1058-1074, 2022 May.
Artículo en Inglés | MEDLINE | ID: mdl-35278193

RESUMEN

Brivaracetam (BRV) is an anti-seizure drug for the treatment of focal and generalized epileptic seizures shown to augment short-term synaptic fatigue by slowing down synaptic vesicle recycling rates in control animals. In this study, we sought to investigate whether altered short-term synaptic activities could be a pathological hallmark during the interictal periods of epileptic seizures in two well-established rodent models, as well as to reveal BRV's therapeutic roles in altered short-term synaptic activities and low-frequency band spontaneous brain hyperactivity in these models. In our study, the electrophysiological field excitatory post-synaptic potential (fEPSP) recordings were performed in rat hippocampal brain slices from the CA1 region by stimulation of the Schaffer collateral/commissural pathway with or without BRV (30 µM for 3 h) in control or epileptic seizure (induced by pilocarpine (PILO) or high potassium (h-K+)) models. Short-term synaptic activities were induced by 5, 10, 20, and 40-Hz stimulation sequences. The effects of BRV on pre-synaptic vesicle mobilization were visually assessed by staining the synaptic vesicles with FM1-43 dye followed by imaging with a two-photon microscope. In the fEPSP measurements, short-term synaptic fatigue was found in the control group, while short-term synaptic potentiation (STP) was detected in both PILO and h-K+ models. STP was decreased after the slices were treated with BRV (30 µM) for 3 h. BRV also exhibited its therapeutic benefits by decreasing abnormal peak power (frequency range of 8-13 Hz, 31% of variation for PILO model, 25% of variation for h-K+ model) and trough power (frequency range of 1-4 Hz, 66% of variation for PILO model, 49% of variation for h-K+ model), and FM1-43 stained synaptic vesicle mobility (64% of the variation for PILO model, 45% of the variation for h-K+ model) in these epileptic seizure models. To the best of our knowledge, this was the first report that BRV decreased the STP and abnormal low-frequency brain activities during the interictal phase of epileptic seizures by slowing down the mobilization of synaptic vesicles in two rodent models. These mechanistic findings would greatly advance our understanding of BRV's pharmacological role in pathomechanisms of epileptic seizures and its treatment strategy optimization to avoid or minimize BRV-induced possible adverse side reactions.


Asunto(s)
Anticonvulsivantes , Vesículas Sinápticas , Animales , Anticonvulsivantes/farmacología , Anticonvulsivantes/uso terapéutico , Encéfalo , Fatiga/inducido químicamente , Fatiga/tratamiento farmacológico , Pilocarpina , Pirrolidinonas/efectos adversos , Ratas , Roedores , Convulsiones/tratamiento farmacológico
11.
Front Plant Sci ; 12: 770556, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34675959

RESUMEN

[This corrects the article DOI: 10.3389/fpls.2020.581513.].

12.
Neuroscience ; 475: 83-92, 2021 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-34534635

RESUMEN

Network oscillations at γ frequency band (30-80 Hz), generated by the interaction between inhibitory interneurons and excitatory neurons, have been proposed to be associated with higher brain functions such as learning and memory. Dopamine (DA), one of the major CNS transmitters, modulates hippocampal γ oscillations but the intracellular mechanisms involved remain elusive. In this study, we recorded kainate-induced γ oscillations in the CA3 area of rat hippocampal slices, and found that DA strongly enhanced γ power, which was largely blocked by dopamine receptor 1 (DR1) antagonist SCH23390, receptor tyrosine kinase (RTK) inhibitor UNC569 and ERK inhibitor U0126, partially blocked by D2/3R antagonist raclopride, PKA inhibitor H89 and PI3K inhibitor wortmannin, but not affected by AKT inhibitor TCBN or NMDAR antagonist D-AP5. Our results indicate that DA-mediated γ enhancement is involved in the activation of signaling pathway of DR1/2-RTK-ERK. Our data demonstrate a strong, rapid modulation of DA on hippocampal γ oscillations and provide a new insight into cellular mechanisms of DA-mediated γ oscillations.


Asunto(s)
Dopamina , Fosfatidilinositol 3-Quinasas , Animales , Hipocampo , Ácido Kaínico , Neuronas , Ratas
13.
Sci Total Environ ; 800: 149499, 2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34426306

RESUMEN

Rapid urbanization and increasing population have widely caused the urban heat island effect. Due to the decreasing distance between cities, there is an urgent need to reevaluate regional heat island intensity (RHII) in an urban agglomeration scale by considering all cities together instead of from conventional single city perspective. Using cropland land surface temperature as the reference temperature, we assessed the diurnal and seasonal RHII variations in the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) urban agglomeration in South China. The boosted regression trees (BRT) method was then used to analyze the relative influence and marginal effect of possible drivers to disentangle their underlying driving mechanisms. Results showed that the daytime RHII spatial patterns averaged over the period 2003-2017 illustrated higher intensity and greater heterogeneity than their nighttime counterparts, especially for the stronger RHII in the central GBA around the estuary area. Seasonal dynamics of daytime RHII displayed a generally descending trend from summer to winter, but the opposite for night. BRT analyses indicated that at both annual and seasonal scales, vegetation fraction and background temperature had a dominant influence on RHII in daytime and nighttime, respectively. RHII variations were also considerably attributed to other drivers for different seasons. For daytime RHII, the other influential drivers included anthropogenic heat emissions and precipitation in summer, anthropogenic heat emissions and terrain in the transition season, and temperature and albedo in winter. For nighttime RHII, anthropogenic heat emissions for all seasons, vegetation activities for summer and the transition season, and precipitation for winter also had important contributions. The marginal effects detected the different nonlinear responses of diurnal and seasonal RHII to potential drivers, suggesting contrasting driving mechanisms. Results of this study highlight more targeted and informed strategies for RHII mitigation in the GBA and provide helpful insights into RHI evaluation in other urban agglomerations.


Asunto(s)
Monitoreo del Ambiente , Urbanización , China , Ciudades , Cambio Climático , Calor
14.
Front Nutr ; 8: 696355, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34222311

RESUMEN

Peanut allergy is becoming a life-threatening disease that could induce severe allergic reactions in modern society, especially for children. The most promising method applied for deallergization is heating pretreatment. However, the mechanism from the view of spectroscopy has not been illustrated. In this study, near-infrared spectroscopy (NIRS) combined with aquaphotomics was introduced to help us understand the detailed structural changes information during the heating process. First, near-infrared (NIR) spectra of Ara h1 were acquired from 25 to 80°C. Then, aquaphotomics processing tools including principal component analysis (PCA), continuous wavelet transform (CWT), and two-dimensional correlation spectroscopy (2D-COS) were utilized for better understanding the thermodynamic changes, secondary structure, and the hydrogen bond network of Ara h1. The results indicated that about 55°C could be a key temperature, which was the structural change point. During the heating process, the hydrogen bond network was destroyed, free water was increased, and the content of protein secondary structure was changed. Moreover, it could reveal the interaction between the water structure and Ara h1 from the perspective of water molecules, and explain the effect of temperature on the Ara h1 structure and hydrogen-bonding system. Thus, this study described a new way to explore the thermodynamic properties of Ara h1 from the perspective of spectroscopy and laid a theoretical foundation for the application of temperature-desensitized protein products.

15.
Br J Clin Pharmacol ; 87(12): 4823-4830, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34046922

RESUMEN

AIMS: To assess association between quetiapine treatment and risk of new-onset hypothyroidism in schizophrenia patients. METHODS: We conducted a retrospective cohort study in a tertiary hospital in China between January 2016 and December 2018. Schizophrenia patients with normal thyroid tests at admission were included. Hypothyroidism, which was defined as thyroid-stimulating hormone >4.20 mU/L and free thyroxine <12.00 pmol/L, or on L-thyroxine prescriptions, was the outcome measure, and quetiapine treatment between admission and subsequent thyroid test was the exposure measure of this study. Adjusted relative risks and 95% confidence intervals were used to assess the independent association of quetiapine treatment with risk of new-onset hypothyroidism. The dose-response association was further analysed by 3 quetiapine doses: low (≤<=0.2 g/d), medium (0.2-0.6 g/d), and high (>0.6 g/d). RESULTS: A total of 2022 eligible patients were included in the final analysis. Sixty patients (15.0%) in the quetiapine group developed hypothyroidism, while 56 patients (3.5%) in the nonquetiapine group developed hypothyroidism. Relative risk (95% confidence interval) of developing hypothyroidism for quetiapine use was 4.01 (2.86-5.64) after adjusting for several potential confounding factors. A strong dose-response association between quetiapine use and risk of developing hypothyroidism was observed: adjusted relative risks (95% confidence intervals) were 1.00 (0.25-2.59), 4.22 (2.80-6.25) and 5.62 (3.66-8.38), respectively, for low-, medium- and high-dose quetiapine, as compared with no quetiapine. CONCLUSION: Acute phase quetiapine treatment for schizophrenia patients was strongly associated with increased risk of developing new-onset hypothyroidism, with a clear dose-response association.


Asunto(s)
Hipotiroidismo , Fumarato de Quetiapina , Esquizofrenia , Humanos , Hipotiroidismo/inducido químicamente , Hipotiroidismo/epidemiología , Fumarato de Quetiapina/administración & dosificación , Fumarato de Quetiapina/efectos adversos , Estudios Retrospectivos , Esquizofrenia/tratamiento farmacológico , Esquizofrenia/epidemiología , Tiroxina/administración & dosificación
16.
Front Plant Sci ; 11: 581513, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33519842

RESUMEN

Dicranopteris is an ancient and widespread genus of ferns in pantropical regions. Some species of the genus can form dense thickets, and dominate the understory, which are common and key species in tropical and subtropical ecosystems. However, they were mostly cut or burned in forest management because of forming dense thickets which were considered to interfere with forest regeneration and succession. In the current review, we argue that the Dicranopteris species which are able to rapidly colonize barren areas may contribute to ecosystem recovery, resistance to environmental stress, and succession control. Rapid colonization involves prolific spore production, rapid clonal growth, the generation of high surface cover, and the ability to fill gaps; stress resistance includes resistance to abiotic stress, and the ability to reduce soil erosion from rainfall, alien species invasion, and soil contamination and toxicity; and succession facilitation consists of carbon and nutrient sequestration in soil, moderation of the microclimate, alteration of the soil microbial and faunal communities, and determination of which plant species to be established in the next successional stage. All of these ecosystem functions may be beneficial to ecosystem resilience. We expect that the distribution of Dicranopteris will expand in response to global warming, changes in precipitation patterns, increases in soil pollution, deforestation, and land degradation. We recommend that Dicranopteris, as a pioneer fern and a valuable component of tropical and subtropical ecosystems, needs more attention in future research and better management practices to promote forest regeneration and succession.

17.
Ecotoxicol Environ Saf ; 187: 109750, 2020 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-31655412

RESUMEN

Drought and nitrogen (N) deposition are important components of global climate and environmental change. In this greenhouse study, we investigated the ecophysiological responses of the seedlings of three subtropical forest plant species (Schima superba, Castanopsis fissa, and Michelia macclurei) to short-term experimental drought stress, N addition, and their interaction. The results showed that drought stress reduced the activities of antioxidant enzymes [superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT)] and total antioxidant capacity (T-AOC), but increased the malondialdehyde (MDA), abscisic acid (ABA), and proline (PRO) contents in plants. The PRO content, T-AOC, and antioxidant enzyme activities were increased, and ABA and MDA contents were decreased by N addition alone. Furthermore, N addition under drought stress increased antioxidant enzymes activities, PRO content, and T-AOC. The treatments, however, did not significantly affect the chlorophyll fluorescence parameters of the species. T-AOC was positively correlated with antioxidant enzyme activities in each species, indicating that antioxidant enzymes were important for plant resistance to oxidative stress. MDA content increased with the increase of ABA content, indicating that ABA may help regulate stomatal movement and drought-induced oxidative injury in plants. T-AOC was positively correlated with PRO content, probably because PRO participated in osmotic regulation of cells and increased osmotic stress resistance. These results indicate that N addition can reduce drought stress of subtropical forest plants and will help researchers predict how evergreen broad-leaved forests will respond to global change in the future.


Asunto(s)
Contaminantes Atmosféricos/toxicidad , Antioxidantes/metabolismo , Sequías , Compuestos de Nitrógeno/toxicidad , Estrés Oxidativo/efectos de los fármacos , Árboles/efectos de los fármacos , China , Monitoreo del Ambiente , Fagaceae/efectos de los fármacos , Fagaceae/metabolismo , Bosques , Ósmosis/efectos de los fármacos , Presión Osmótica/efectos de los fármacos , Árboles/metabolismo , Clima Tropical
18.
Artículo en Inglés | MEDLINE | ID: mdl-30818218

RESUMEN

For the modeling of near infrared spectroscopy (NIRS), the accuracy of the basic data, the stability of the spectra and the optimality of variables selection method were the important factors. In this paper, a novel optimization strategy for NIRS modeling was proposed, which was formed by data mean and ratio of absorbance to concentration (RATC) methods. The data mean method was aim to obtain accurate basic data and stable spectra, the RATC method was aim to select the optimal variables and compared with other variables selection methods (FiPLS, BiPLS, CC, UVE). The experimental subject was raw human plasma, with this novel optimization strategy, the predictive capability of NIRS model of its total protein (TP) content had been improved. At the same time, the public NIRS testing data (water, protein, oil, starch of corn and octane of gasoline) were used to verify the proposed variables selection method, and the predictive capability of these models of different parameters were also improved. To some extent, the optimization strategy of NIRS modeling provided theoretical supports for the development of protein content analyzer of NIRS and the quick determination of parameters of biologics and other materials.


Asunto(s)
Espectroscopía Infrarroja Corta/métodos , Espectroscopía Infrarroja Corta/normas , Absorción Fisicoquímica , Proteínas Sanguíneas/análisis , Calibración , Gasolina/análisis , Humanos , Modelos Químicos , Zea mays/química
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 201: 153-160, 2018 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-29747085

RESUMEN

N-acetyl-d-glucosamine (GlcNAc) is a microbial fermentation product, and NIR spectroscopy is an effective process analytical technology (PAT) tool in detecting the key quality attribute: the GlcNAc content. Meanwhile, the design of NIR spectrometers is under the trend of miniaturization, portability and low-cost nowadays. The aim of this study was to explore a portable micro NIR spectrometer with the fermentation process. First, FT-NIR spectrometer and Micro-NIR 1700 spectrometer were compared with simulated fermentation process solutions. The Rc2, Rp2, RMSECV and RMSEP of the optimal FT-NIR and Micro-NIR 1700 models were 0.999, 0.999, 3.226 g/L, 1.388 g/L and 0.999, 0.999, 1.821 g/L, 0.967 g/L. Passing-Bablok regression method and paired t-test results showed there were no significant differences between the two instruments. Then the Micro-NIR 1700 was selected for the practical fermentation process, 135 samples from 10 batches were collected. Spectral pretreatment methods and variables selection methods (BiPLS, FiPLS, MWPLS and CARS-PLS) for PLS modeling were discussed. The Rc2, Rp2, RMSECV and RMSEP of the optimal GlcNAc content PLS model of the practical fermentation process were 0.994, 0.995, 2.792 g/L and 1.946 g/L. The results have a positive reference for application of the Micro-NIR spectrometer. To some extent, it could provide theoretical supports in guiding the microbial fermentation or the further assessment of bioprocess.


Asunto(s)
Fermentación/fisiología , Glucosamina/análisis , Espectroscopía Infrarroja Corta/métodos , Reactores Biológicos , Estudios de Factibilidad , Glucosamina/metabolismo , Microtecnología , Análisis de Regresión
20.
Sci Rep ; 6: 37188, 2016 11 18.
Artículo en Inglés | MEDLINE | ID: mdl-27857187

RESUMEN

Long-term ecological data play a vital role in ecological conservation and restoration, however, using information from local forest soil pollen data to assist restoration remains a challenge. This study analyzed two data sets, including 1) surface soil pollen (0-5 cm) and current vegetation data from four near-natural communities and four plantations, and 2) fossil pollen from soil profiles (0-80 cm) from a regional climax community and a degraded land. The pollen representativeness and similarity indexes were calculated. The results showed a low similarity between soil pollen and current vegetation (about 20%) thus forest soil pollen data should be used with caution when defining reference ecosystems. Pollen from Gironniera and Rutaceae which were abundant in broadleaved forest, were also detected in the 40-80 cm layer of a soil profile from the degraded land, which indicates its restoration possibility. Our study considered that the early restoration stage of the study area may benefit from using plant taxa of Pinus, Poaceae, Lonicera, Casuarina, Trema and Quercus. As Pinus, Castanopsis, Gironniera, Rutaceae, Helicia, Randia, Poaceae, Dicranopteris and Pteris always existed during succession, for regional forest restoration under global climate change, the roles of such "stable species" should be considered.


Asunto(s)
Cambio Climático , Bosques , Polen , Suelo
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...