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1.
Small ; : e2403821, 2024 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-38949043

RESUMO

Compared to the bulk heterojunction (BHJ) devices, the quasiplanar heterojunction (Q-PHJ) exhibits a more stable morphology and superior charge transfer performance. To achieve both high efficiency and long-term stability, it is necessary to design new materials for Q-PHJ devices. In this study, QxIC-CF3 and QxIC-CH3 are designed and synthesized for the first time. The trifluoromethylation of the central core exerts a modulatory effect on the molecular stacking pattern, leveraging the strong electrostatic potential and intermolecular interactions. Compared with QxIC-CH3, the single crystal structure reveals that QxIC-CF3 exhibits a more compact 2D linear stacking behavior. These benefits, combined with the separated electron and hole transport channels in Q-PHJ device, lead to increased charge mobility and reduced energy loss. The devices based on D18/QxIC-CF3 exhibit an efficiency of 18.1%, which is the highest power conversion efficiency (PCE) for Q-PHJ to date. Additionally, the thermodynamic stability of the active layer morphology enhances the lifespan of the aforementioned devices under illumination conditions. Specifically, the T80 is 420 h, which is nearly twice that of the renowned Y6-based BHJ device (T80 = 220 h). By combining the advantages of the trifluoromethylation and Q-PHJ device, efficient and stable organic solar cell devices can be constructed.

2.
Small ; : e2309169, 2023 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-38072767

RESUMO

The conjugate expansion of nonfullerene acceptors is considered to be a promising approach for improving organic photovoltaic performance because of its function in tuning morphological structure and molecular stacking behavior. In this work, two nonfullerene acceptors are designed and synthesized using a 2D π-conjugate expansion strategy, thus enabling the construction of highly-efficient organic solar cells (OSCs). Compared with YB2B (incorporating dibromophenanthrene on the quinoxaline-fused core), YB2T (incorporating dibromobenzodithiophene on the quinoxaline-fused core) has red-shifted spectral absorption and better charge transport properties. Moreover, the more orderly and tightly intermolecular stacking of YB2T provides the possibility of forming a more suitable phase separation morphology in blend films. Through characterization and analysis, the YB2T-based blend film is found to have higher exciton dissociation efficiency and less charge recombination. Consequently, the power conversion efficiency (PCE) of 17.05% is achieved in YB2T-based binary OSCs, while YB2B-based devices only reached 10.94%. This study demonstrates the significance of the aromatic-ring substitution strategy for regulating the electronic structure and aggregation behavior of 2D nonfullerene acceptors, facilitating the development of devices with superior photovoltaic performance.

3.
ACS Appl Mater Interfaces ; 15(35): 41590-41597, 2023 Sep 06.
Artigo em Inglês | MEDLINE | ID: mdl-37610376

RESUMO

New strategies for the molecular design to construct efficient electron-deficient units for D-A-type donor copolymers are urgently needed. Halogenation of electron-deficient units (A) has been shown to be the most effective strategy reported to date with which to produce high-performance donor polymers. Herein, we have constructed two different trifluoromethyl-substituted polymer donors, PBQP-CF3 and PBQ-CF3. The trifluoromethylation process typically involves complex protocols, which are not widely used in the synthesis of polymer donors. Accordingly, we have developed a single-step, one-pot synthesis of the new trifluoromethyl-substituted electron-deficient unit (A) of PBQ-CF3. The strong electron-withdrawing ability of the trifluoromethyl group ensures deeper highest occupied molecular orbital (HOMO) energy levels, and the non-covalent bonding interactions of the fluorine atoms are beneficial to the regulation of aggregation properties. Thus, both of the trifluoromethyl-substituted polymer donors obtained much higher power conversion efficiency (PCE) than PBDP-H (6.66%). PBQ-CF3 exhibits a deeper HOMO energy level, better aggregation behavior, and higher hole mobility than PBQP-CF3. PBQ-CF3-based quasiplanar heterojunction (Q-PHJ) devices therefore achieve simultaneously enhanced open-circuit voltage (VOC), short-circuit current density (JSC), and fill factor (FF) and an impressive PCE (16.02%), which is much higher than that obtained by PBQP-CF3-based devices (12.57%). This work reveals a promising path to synthesis of the trifluoromethylation polymer donors and demonstrates that the trifluoromethylation strategy can be used to enhance the photovoltaic performance.

4.
J Am Chem Soc ; 145(33): 18642-18648, 2023 08 23.
Artigo em Inglês | MEDLINE | ID: mdl-37562030

RESUMO

We disclose unified, protecting-group-free, bioinspired divergent total syntheses of eight allo-cedrane and seco-prezizaane Illicium sesquiterpenes and formal syntheses of five anislactone sesquiterpenes. The efficiency of our approach derives from rapid access to the 15-carbon tricyclic carboxylic acid through cationic epoxide-ene cyclization and HAT oxygenation, transformation of this intermediate into three distinct tricyclic precursors via Lewis acid-mediated skeletal reorganizations, subsequent programmed oxidation level enhancement, and a biomimetic oxidation-initiated skeletal rearrangement cascade. Consequently, we created a synthetic correlation map of the three most prevalent Illicium sesquiterpene families.


Assuntos
Illicium , Sesquiterpenos , Humanos , Ciclização , Oxirredução , Estrutura Molecular
5.
Front Microbiol ; 13: 812991, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35359725

RESUMO

Arsenate [As(V)] is a toxic metalloid and has been observed at high concentrations in groundwater globally. In this study, a bioelectrochemical system (BES) was used to efficiently remove As(V) from groundwater, and the mechanisms involved were systematically investigated. Our results showed that As(V) can be efficiently removed in the BES cathode chamber. When a constant cell current of 30 mA (I cell , volume current density = 66.7 A/m3) was applied, 90 ± 3% of total As was removed at neutral pH (7.20-7.50). However, when I cell was absent, the total As in the effluent, mainly As(V), had increased approximately 2-3 times of the As(V) in influent. In the abiotic control reactor, under the same condition, no significant total As or As(V) removal was observed. These results suggest that As(V) removal was mainly ascribed to microbial electrosorption of As(V) in sludge. Moreover, part of As(V) was bioelectrochemically reduced to As(III), and sulfate was also reduced to sulfides [S(-II)] in sludge. The XANES results revealed that the produced As(III) reacted with S(-II) to form As2S3, and the residual As(III) was microbially electroadsorbed in sludge. This BES-based technology requires no organic or chemical additive and has a high As(V) removal efficiency, making it an environment-friendly technique for the remediation of As-contaminated groundwater.

6.
Explore (NY) ; 18(6): 706-709, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34551882

RESUMO

Ganglion cysts are benign soft tissue tumors most commonly encountered in the hand. The most widely used approaches are watchful waiting, non-operative aspiration, steroid injection and surgical removal, but these are often associated with high recurrence rates and complications. We report the case of a 38-year-old female graphic designer who presented to the acupuncture outpatient department with chief complaint of an enlarging, painless lump on the left wrist for 5 months. Ultrasound analysis demonstrated a 1.8 * 1.07 cm mass lesion on the dorsum of the left wrist. Her wrist range of motion was approximately 40° active flexion and 30° active extension. Discomfort was the maximum during wrist extension. For each acupuncture treatment, three needles (0.30 mm in diameter, 40 mm in length) were inserted transversely at an angle of 15° and to a depth of 15-20 mm. When the needles were removed after the first treatment, ultrasound analysis showed that the mass lesion decreased in size from 1.8 cm to 1.72 cm, and further to 1.55 cm the following day. The patient underwent treatment every other day for a total of six treatments over a three-week period. By the end of the sixth visit, the cyst had become insignificant in size. The treatment outcome suggests that acupuncture may have effects in perforating the cyst wall and promoting the absorption of the gelatinous fluid within the cyst. Acupuncture may be a viable treatment option with reduced complications and potential faster recovery time for dorsal wrist ganglions.


Assuntos
Terapia por Acupuntura , Cistos Glanglionares , Feminino , Humanos , Adulto , Cistos Glanglionares/cirurgia , Punho/cirurgia , Articulação do Punho/cirurgia , Mãos
7.
Org Lett ; 23(17): 6972-6976, 2021 09 03.
Artigo em Inglês | MEDLINE | ID: mdl-34397211

RESUMO

Omphalane diterpenoids usually contain a cyclohexane-fused bicyclo[3.2.1]octane scaffold embedded with two continuous quaternary carbon centers, which pose considerable challenges to synthetic chemists. Herein, we reported the first total synthesis of omphalic acid with high stereochemical control, featuring an intermolecular Diels-Alder cycloaddition, ring reorganization through Criegee oxidative cleavage and programmed aldol condensations, conformationally controlled hydrogenation, and Pd-catalyzed carboxylation. The absolute configuration of omphalic acid was defined for the first time via the asymmetric total synthesis facilitated by a derivatization resolution protocol.


Assuntos
Compostos Bicíclicos com Pontes/química , Diterpenos/química , Octanos/química , Catálise , Reação de Cicloadição , Hidrogenação , Estrutura Molecular , Estereoisomerismo
8.
Artigo em Inglês | MEDLINE | ID: mdl-33680055

RESUMO

Moxa floss is a type of biomass used as the main combustion material in moxibustion, a therapy that applies heat from moxa floss combustion to points or body areas for treatment. Safety concerns regarding moxa smoke have been raised in recent years. Since moxa floss is the source material in moxibustion, its thermal behavior and pyrolysis products would be related to the products formed in moxa smoke. This work aims to understand the thermal behavior of moxa floss and investigate the pyrolysis products generated from moxa floss combustion. Six commercial moxa floss samples of 3 storage years and 10 storage years, and of low, medium, and high ratios, were selected. The kinetic data from moxa floss combustion was carried out by a thermogravimetric analyzer. Pyrolysis-gas chromatography and mass spectroscopy using a gas chromatograph and mass spectrometer equipped with a pyroprobe were used to examine the pyrolysis products. Thermogravimetric profiles for all the samples were overall similar and showed a monotonic weight decrease. The range of intensive reaction temperature occurred between 150°C and 450°C, which was characterized by a major weight loss and accompanied by an exothermal degradation of the main components. The average ignition temperature for the samples of 3 and 10 storage years was 218.3°C and 222.6°C, respectively, which was lower than most herbaceous plants. The identified pyrolysis products include monocyclic aromatic hydrocarbons, polycyclic aromatic hydrocarbons, ketones, acids, and alkanes. All were of relatively low intensities of below 5% in relative abundance. No volatiles were detected in the samples of 10 storage years. The relatively low values of ignition temperature suggested that moxa floss is more combustible and can be ignited more easily than other herbaceous plants. This may explain why moxa floss has remained as the preferred material used for moxibustion over the years.

9.
Medicine (Baltimore) ; 99(33): e21556, 2020 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-32872004

RESUMO

Moxa floss is the primary material used in moxibustion, an important traditional Chinese medicine therapy that uses ignited moxa floss to apply heat to the body for disease treatment. Till date, there is no available data regarding quality control of different grades of moxa floss. The objectives of this study were to explore the probative value of the electronic nose (e-nose) in differentiating different quality grades of commercial moxa floss sold in China, and to investigate if data mining techniques could be used to optimize the sensor array while retaining classification accuracy of the samples. The e-nose with 12 metal oxide semiconductor type sensors was used to analyze the odor profiles of 15 commercial moxa floss samples of different quality grades. Feature selection algorithms using principal component analysis (PCA) and BestFirst (BC) coupled with correlation-based feature subset selection (CfsSubsetEval) method were used to obtain the most efficient feature subsets. Results for the BC feature selection method identified 3 optimized sensors (S2, S6, and S11), suggesting that aromatic compounds relate more to the identification of the samples. Radial basis function (RBF), multilayer perceptron (MLP), and random forests (RF) performed well in discriminating the samples, retaining prediction accuracies above 85%, which achieved cost-effectiveness and operational simplicity, while retaining prediction accuracy. The e-nose could be a rapid and nondestructive method for objective preliminary classification of quality grades of moxa floss and may be used for future studies related to moxa products safety and quality.


Assuntos
Medicamentos de Ervas Chinesas/classificação , Nariz Eletrônico , Moxibustão , Fumaça/análise , Algoritmos , China , Mineração de Dados , Humanos , Análise de Componente Principal
10.
Bioresour Technol ; 309: 123363, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32305849

RESUMO

The piggery digestate of high ammonia was mixed with the anoxic aerated effluent of high nitrate and phosphorus, to cultivate a microalgal-bacterial consortium for simultaneous pollution removal and resource recovery. The highest removal of total inorganic nitrogen was achieved at 324.77 mg/L in 40% piggery digestate mixed with 60% anoxic aerated effluent, along with the most microalgae biomass production. The crude protein and fatty acids of C14-C20 in microalgae cells were 21.80% and 69.78%, indicating that this mixing strategy could produce abundant microalgal biomass suitable for biofuel generation and animal feed. High-throughput sequencing showed that microbial diversity increased and Paenibacillus, Thiopseudomonas and Pseudomonas were the dominant species promoting microalgal growth. Overall, these results provided a new insight of mixing two types of wastewaters for cultivating microalgal-bacterial consortia, to remove contamination and recover nutrients simultaneously.


Assuntos
Microalgas , Animais , Biomassa , Nitrogênio , Fósforo , Águas Residuárias
11.
Environ Pollut ; 258: 113790, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31918063

RESUMO

In situ immobilization of heavy metals in contaminated soils using industrial by-products is an attractive remediation technique. In this work, titanium gypsum (TG) was applied at two levels (TG-L: 0.15% and TG-H: 0.30%) to simultaneously reduce the uptake of cadmium (Cd), lead (Pb) and arsenic (As) in rice grown in heavy metal contaminated paddy soils. The results showed that the addition of TG significantly decreased the pH and dissolved organic carbon (DOC) in the bulk soil. TG addition significantly improved the rice plants growth and reduced the bioavailability of Cd, Pb and As. Particularly, bioavailable Cd, Pb and As decreased by 35.2%, 38.1% and 38.0% in TG-H treatment during the tillering stage, respectively. Moreover, TG application significantly reduced the accumulation of Cd, Pb and As in brown rice. Real-time PCR analysis demonstrated that the relative abundance of sulfate-reducing bacteria increased with the TG application, but not for the iron-reducing bacteria. In addition, 16S rRNA sequencing analysis revealed that the relative abundances of heavy metal-resistant bacteria such as Bacillus, Sulfuritalea, Clostridium, Sulfuricella, Geobacter, Nocardioides and Sulfuricurvum at the genus level significantly increased with the TG addition. In conclusion, the present study implied that TG is a potential and effective amendment to immobilize metal(loid)s in soil and thereby reduce the exposure risk of metal(loid)s associated with rice consumption.


Assuntos
Arsênio/isolamento & purificação , Cádmio/isolamento & purificação , Sulfato de Cálcio/química , Chumbo/isolamento & purificação , Poluentes do Solo/isolamento & purificação , Titânio/química , Bactérias/classificação , Oryza , RNA Ribossômico 16S , Microbiologia do Solo
12.
Gynecol Obstet Invest ; 77(4): 217-23, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24751759

RESUMO

BACKGROUND: Polycystic ovary syndrome (PCOS) is one of the most common endocrine disorders in women. The data on this syndrome in a Chinese community are limited. METHODS: A community-based cross-sectional survey was undertaken. Cluster-randomized sampling was used. Female residents of Chengdu aged between 12 and 44 were included according to the constituent ratio of the female population of Sichuan province. We used three diagnostic criteria to determine the prevalence: the National Institutes of Health diagnostic criteria of PCOS (NIH-1990), the revised Rotterdam diagnostic criteria of PCOS (Rott-2003), and the recommended diagnostic criteria of PCOS by the Androgen Excess Society (AES-2006). RESULTS: 1,645 participants were included. The prevalence of PCOS in women aged between 12 and 44 was 7.1, 11.2 and 7.4%, respectively, according to the three different criteria. After the onset of puberty, the prevalence of PCOS increased rapidly from 12 to 14 years of age, peaked between 15 and 24 and decreased gradually thereafter and reached its lowest point before menopause. CONCLUSIONS: The prevalence of PCOS in this study was in the PCOS prevalence range from existing studies. According to the trend of prevalence, PCOS might be a temporary condition.


Assuntos
Síndrome do Ovário Policístico/epidemiologia , Adolescente , Adulto , Criança , China/epidemiologia , Estudos Transversais , Feminino , Humanos , Síndrome do Ovário Policístico/diagnóstico , Prevalência , Adulto Jovem
13.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 30(2): 355-8, 2013 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-23858762

RESUMO

This paper is aimed to analyze the correlation between serum free testosterone (FT) and total testosterone (TT) to acquire a cutoff about using total testosterone to diagnose hyperandrogenism in Chengdu females. We investigated 1854 women by cluster sampling method, detected their serum FT levels and TT levels, scored relative items, analyzed the correlation and made the ROC curve to get a cutoff of TT levels. Serum FT had a linear correlation with serum TT (r = 0.597, r2 = 0.356, P < 0.001). The cutoff value was 0.635 ng/mL. The specificity and sensitivity were 76.3% and 77.24%, respectively. No correlation found between serum FT and Ferriman-Gallway Score (P = 0.392). Positive correlations were seen between serum FT and Plewig-Kligman Score (r = 0.137, P < 0.001), serum TT and Ferriman-Gallway Score (r = 0.069, P = 0.003) and serum TT and Plewig-Kligman Score (r = 0.092, P < 0.001). There is a linear correlation between serum FT and TT. We can diagnose hyperandrogenism according to the serum TT cutoff value (0.635 ng/mL). Its clinical symptoms are not paralleled with the biochemical test results.


Assuntos
Testosterona/sangue , Adolescente , Adulto , Criança , China , Feminino , Humanos , Hiperandrogenismo/sangue , Pessoa de Meia-Idade , Valores de Referência , Estudos de Amostragem , Adulto Jovem
14.
Nan Fang Yi Ke Da Xue Xue Bao ; 31(10): 1753-6, 2011 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-22027783

RESUMO

OBJECTIVE: To investigate the relationship between 8 endocrine-disrupting chemicals in the serum and insulin resistance in patients with polycystic ovary syndrome (PCOS). METHODS: This study was conducted among 60 patients with PCOS, including 23 with insulin resistance (PCOS-IR) and 37 without insulin resistance (PCOS-NIR), and 29 non-PCOS women seeking medical attention for infertility or menstrual disorder (control group). The serum levels of 6 phthalic acid esters (PEAs), bisphenol A (BPA) and octylphenol (OP) were measured in all the subjects. RESULTS: The levels of PAEs, BPA and OP showed no significant differences between PCOS patients and the control group (P>0.05). The serum level of OP was significantly lower in patients PCOS-IR than in those with PCOS-NIR (47.89 ng/ml vs 60.24 ng/ml, P<0.05). CONCLUSION: PEAs and BPA do not produce obvious effect on the pathogenesis of PCOS or contribute to insulin resistance, but OP may play a role in insulin resistance in PCOS patients.


Assuntos
Disruptores Endócrinos/efeitos adversos , Disruptores Endócrinos/sangue , Poluentes Ambientais , Resistência à Insulina , Síndrome do Ovário Policístico/sangue , Adulto , Compostos Benzidrílicos/efeitos adversos , Compostos Benzidrílicos/sangue , Estudos de Casos e Controles , Poluentes Ambientais/efeitos adversos , Poluentes Ambientais/sangue , Feminino , Humanos , Fenóis/efeitos adversos , Fenóis/sangue , Ácidos Ftálicos/efeitos adversos , Ácidos Ftálicos/sangue , Síndrome do Ovário Policístico/fisiopatologia , Adulto Jovem
15.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi ; 27(3): 636-40, 2010 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-20649035

RESUMO

It is the intent of this investigation to gain an insight into the relationship of serum total adiponectin with polycystic ovary syndrome (PCOS) and insulin resistance. Fifty-eight PCOS patients were enrolled (29 with high serum insulin level and 29 without), at the same time, 29 non-PCOS women with normal weight were included as control. The influencing factors of total adiponectin, PCOS and insulin resistance were analyzed. The serum total adiponectin of PCOS patients and all participants were found to be negatively related to waist hip ratio (r = -0.39, r = -0.36) and InHOMA-IR (r = -0.53, r = -0.45), respectively. Adiponectin was not a protective factor of PCOS (P > 0.1), but it was that of PCOS-insulin resistance (OR = 0.81; 95% CI: 0.67-0.97; P = 0.02). LH/FSH (OR = 1.51; 95% CI: 1.16-1.96; P = 0.01) and InHOMA-IR (OR = 1.26; 95% CI: 1.10-1.44; P = 0.01) were risk factors of PCOS, and waist hip ratio was that of PCOS-insulin resistance (OR = 8.57; 95% CI, 2.14-34.30, P = 0.01). Adiponectin might influence fasting insulin and InHOMA-IR (B = -0.22, P = 0.001; B = -0.02, P = 0.002). These data signify that adiponectin is not directly related with PCOS, but it is related with PCOS-HL Adiponectin might participate in the pathophysiologic mechanism of PCOS by influencing insulin sensitivity.


Assuntos
Adiponectina/sangue , Resistência à Insulina/fisiologia , Síndrome do Ovário Policístico/sangue , Síndrome do Ovário Policístico/fisiopatologia , Adulto , Feminino , Humanos , Relação Cintura-Quadril , Adulto Jovem
16.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 40(5): 877-80, 892, 2009 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-19950604

RESUMO

OBJECTIVE: To investigate the tyrosine autophosphorylation of insulin receptors in patients with polycystic ovary syndrome (PCOS). METHODS: Forty patients with PCOS and 20 age- and body mass index matched healthy women were included in the study. The patients with PCOS were classified as HI-PCOS (n=20) or non-HI-PCOS (n=20) based on the fasting insulin level (>or< or =15 mIU/L). 1) Serum gonadotropins and ovarian steroids were determined. Oral glucose tolerance tests (OGTT) and insulin releasing tests were performed to calculate the insulin resistance index (HOMA-IR). 2) Blood samples were obtained at five time-points during the OGTT (Fasting and 30 min, 60 min, 120 min, and 180 min after taking 75 g glucose orally). The erythrocytes were isolated and the autophosphorylation insulin receptors (APIR) and total insulin receptors (TIR) were measured by enzymatic immunoassay. 3) The in vivo autophosphorylation of insulin receptors was indicated by the APIR/TIR ratio. RESULTS: The HI-PCOS patients had lower APIR/TIR ratio than the non-HI-PCOS patients and healthy controls at the 60th minute after OGTT (P<0.05). No differences in other time-points were significant. CONCLUSION: The autophosphorylation of insulin receptors in HI-PCOS patients decrease, which might be a mechanism for insulin resistance in patients with PCOS.


Assuntos
Antígenos CD/metabolismo , Eritrócitos/metabolismo , Resistência à Insulina , Síndrome do Ovário Policístico/sangue , Receptor de Insulina/metabolismo , Adulto , Estudos de Casos e Controles , Feminino , Humanos , Fosforilação , Tirosina/metabolismo , Adulto Jovem
17.
Guang Pu Xue Yu Guang Pu Fen Xi ; 29(1): 114-8, 2009 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-19385218

RESUMO

Soil samples in the depth from 0 to 20 cm were scooped from agricultural region beside mines and prepared for determination of As concentration, Fe concentrations and organic matter content. At the same time they were scanned by mobile hyperspectral radiometer for visible and near-infrared spectra. Savitzky-Golay filter was used to smooth noises in spectrum curve because of some low signal-to-noise ratios in some regions of visible and near-infrared light, and all the spectra were resampled with the spectral interval of 10 nm. Before principal component regression and partial least square regression models were constructed for predicting As concentration, Fe concentrations and OM content, several spectral preprocessing techniques like first/second derivative (F/SD), baseline correction (B), standard normalized variate (SNV), multiplicative scatter correction (MSC) and continuum removal (CR) were used for promotion of models' robustness and predicting performance. For limited samples, cross validation was carried out by repeated leave-one-out procedure, and root mean square error of prediction (RMSEP) was used for validating the prediction ability of constructed models. In this study principal component regression models behave better than partial least square regression models in representing regressing ability, reducing risk of over-fitting with less factors and ensuring models' accuracy and pertinences (relative RMSEP and R2). Preprocessing techniques of SNV, MSC and CR improve obviously the prediction ability of models for As concentration, Fe concentrations and OM content with relative RMSEP equal to 0.3040, 0.1443 and 0.1712, with number of factors equal to 5, 3 and 3, respectively. The analysis of regression vectors of selected optimal PCR models shows that several important wavelengths are simultaneously taken and helpful for prediction performance: 450, 1,000, 1,400, 1,900, 2,050, 2,200, 2,250, 2,400 and 2,470 nm. Application of the calibrated models to soil contamination of croplands is promising. Concentrations of soil contaminants and contents of other matter can be determined by reflectance spectroscopy with high spectra resolution, which would provide potent reference for remote sensing monitoring of soil and environmental quality.


Assuntos
Poluentes do Solo/análise , Solo/análise , Espectrofotometria Infravermelho/métodos , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Luz , Mineração
18.
Sensors (Basel) ; 9(3): 1738-53, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-22573984

RESUMO

Desertification is a serious threat to the ecological environment and social economy in our world and there is a pressing need to develop a reasonable and reproducible method to assess it at different scales. In this paper, the Ordos Plateau in China was selected as the research region and a quantitative method for desertification assessment was developed by using Landsat MSS and TM/ETM+ data on a regional scale. In this method, NDVI, MSDI and land surface albedo were selected as assessment indicators of desertification to represent land surface conditions from vegetation biomass, landscape pattern and micrometeorology. Based on considering the effects of vegetation type and time of images acquired on assessment indictors, assessing rule sets were built and a decision tree approach was used to assess desertification of Ordos Plateau in 1980, 1990 and 2000. The average overall accuracy of three periods was higher than 90%. The results showed that although some local places of Ordos Plateau experienced an expanding trend of desertification, the trend of desertification of Ordos Plateau was an overall decrease in from 1980 to 2000. By analyzing the causes of desertification processes, it was found that climate change could benefit for the reversion of desertification from 1980 to 1990 at a regional scale and human activities might explain the expansion of desertification in this period; however human conservation activities were the main driving factor that induced the reversion of desertification from 1990 to 2000.

19.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 38(6): 980-3, 2007 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-18095601

RESUMO

OBJECTIVE: This study observed the influence on hormone, embryos and clinical outcomes when the starting time of controlled ovarian hyperstimulation (COH) was delayed after applying a half-dose depot gonadotropin-releasing hormone agonist (GnRHa). METHODS: A total 207 cycles were divided into 3 groups: control group (98 cycles, which performed daily low dose GnRHa during the mid-luteal phase in patients' menstrual cycles and reduced the dosage to a half at the next day 3, and added gonadotropin (Gn), conventional group (63 cycles, in which pituitary desensitization was obtained with a half-dose depot GnRHa in the mid-luteal phase, and then Gn was added at day 3) and delayed group (46 cycles, having the same usage of GnRHa to conventional group, but not adding Gn until day 7). RESULTS: The cancellation rate of cycle in conventional group was the highest (P < 0.01). At the beginning of COH, serum E2 and LH levels in delayed and control group were significantly higher than those in conventional group (P < 0.01). On the day of HCG given, serum E2 level in control group was the highest (P < 0.05). LH level in delayed and control group was higher than that in conventional group (P < 0.01). Concerning the clinical efficacy and outcome, the numbers of Gn ampoules and periods for stimulation were less in delayed group than in conventional group; the numbers of retrieved and fertilized oocytes, numbers of good quality embryos, clinical pregnancy rate and embryo implantation rate in delayed and control groups were significantly more than those in conventional group (P < 0.01). In ICSI cycles, the numbers of retrieved oocytes and metaphase II oocytes in delayed and control group were more than those in conventional group. CONCLUSIONS: A half-dose depot GnRHa may produce over suppression to pituitary gland in fertilization in vitro, appropriate delay of COH starting time can decrease ovarian stimulation period and ampoules of Gn, and increase retrieved good quality oocytes, so we could achieve a larger number of good quality embryos with a good chance of implantation.


Assuntos
Transferência Embrionária , Fertilização in vitro , Hormônio Liberador de Gonadotropina/agonistas , Indução da Ovulação/métodos , Hipófise/efeitos dos fármacos , Adulto , Feminino , Fármacos para a Fertilidade Feminina/administração & dosagem , Gonadotropinas/administração & dosagem , Humanos , Infertilidade Feminina/terapia , Gravidez , Taxa de Gravidez , Adulto Jovem
20.
Sichuan Da Xue Xue Bao Yi Xue Ban ; 37(6): 882-5, 2006 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-17236585

RESUMO

OBJECTIVE: To identify the effect of IGF-1 and leptin on the hyperinsulinemia (HI) of patients with polycystic ovarian syndrome (PCOS). METHODS: The case-control compared method was applied to the study. Ninety-two PCOS and 92 control subjects were involved in the study. The group of PCOS was further divided into two subgroups of 46 PCOS-HI and 46 PCOS-NHI. The leptin, IGF-1 and other hormones such as serum testosterone, DHT, DHEA, DHEA-S were measured by RIA method. RESULTS: Leptin and IGF-1 were higher in PCOS group (16.8 +/- 9.8 ng/mL, 214.8 +/- 131.6 ng/mL) than those in control group (11.6 +/- 6.8 ng/ mL, 118.0 +/- 82.9 ng/mL respectively, P < 0.05). Serum leptin level was higher in hyperinsulinemia group (9.2 +/- 10.2 ng/mL) than that in normal insulin group (12.5 +/- 7.6 ng/mL, P < 0.05). IGF-1 (208.7 +/- 109.7 ng/mL vs. 151.7 +/- 120.0 ng/mL, P = 0.66) and fasting glucose (5.1 +/- 0.5 mmol/L vs. 4.9 +/- 0.4 mmol/L, P = 0.15) had no significant difference between two groups. Multiple logistic regression showed that after the body mass index (BMI) adjusted, the testosterone, LH/FSH, DHT, DHEA, and DHEA-S, leptin and IGF-1 showed to be the independent risk factor for PCOS, but not to be for hyperinsulinemia in patients with PCOS. CONCLUSION: The leptin and IGF-1 may contribute to the pathogenesis of PCOS, but the relationship between leptin, IGF-1 and hyperinsulinemia needs more researches to confirm.


Assuntos
Hiperinsulinismo/complicações , Hiperinsulinismo/metabolismo , Fator de Crescimento Insulin-Like I/metabolismo , Leptina/metabolismo , Síndrome do Ovário Policístico/complicações , Síndrome do Ovário Policístico/metabolismo , Adulto , Estudos de Casos e Controles , Feminino , Glucose/metabolismo , Humanos , Modelos Logísticos , Fatores de Risco
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