共查询到20条相似文献,搜索用时 11 毫秒
1.
Synthetic aperture radar (SAR)-based multi-temporal backscatter analysis is a common approach that has been widely used for rice mapping. Co-polarized C-band microwave backscatter (HH or VV) and the co-polarization ratio (HH/VV) are the most commonly used data sets for rice mapping due to their high data availability while the utilization of cross-polarized backscatter (HV or VH) has received less attention. In this study, Sentinel 1A time series – acquired in the dual-polarized (VV/VH) Interferometric Wide (IW) swath mode during the spring growing season (October 2015 to March 2016) in the Mekong Delta – were used to analyse the relationship between the growing cycle of rice plants and the temporal variation of SAR backscatter at different polarizations. Results show that VH backscatter is more sensitive to rice growth than VV backscatter. Several vegetation phenological parameters including beginning date, heading date and the length of the growing season were extracted from the VH backscatter time series. A decision tree approach was applied to delineate rice-cultivated areas based on seasonal phenological parameters. The classification result was validated against a 2015 land use map. The overall classification accuracy is 87.2% (kappa coefficient – κ = 0.71). In addition, the SAR-derived rice area was compared against ground statistical data at the provincial level (coefficient of determination R2 = 0.98). 相似文献
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The standard geolocated Sentinel-2 Multi Spectral Instrument (MSI) L1C data products are defined in spatially overlapping tiles in different Universal Transverse Mercator (UTM) map projection zones. Best practices for reprojection and resampling to properly utilize and benefit from the L1C data format are presented. Three sets of 10 m Sentinel-2 L1C data acquired in the same orbit at different latitudes are examined to illustrate and quantify (a) the spatial properties of the L1C data and provide insights into the occurrence of overlapping tiles and overlapping tiles defined in different UTM zones from the same MSI swath, (b) the geometric implications of resampling and reprojection approaches that consider only the data from one L1C tile and not the data from other tiles in the overlap region that are defined in different UTM zones and (c) a recommended approach that considers all the overlapping L1C tile data and is shown statistically and qualitatively to improve the geometric fidelity of the reprojected resampled L1C data. 相似文献
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M Lehtinen 《Annals of clinical research》1985,17(2):66-70
Herpes Simplex Virus (HSV) specified polypeptide antigens were analyzed by immunoblotting and enzyme-linked immunosorbent assay (ELISA) methods. In general, the virus specified proteins showed marked cross-reactivity. However, the HSV-1 specified glycoprotein C could be detected by HSV-1 infected rabbit antiserum only. Two low molecular weight polypeptides showed considerable reactivity with HSV-2 induced immune sera as revealed by an immunoblocking modification of the immunoblotting method. These proteins may prove useful in the serological diagnosis of HSV Type 1 and Type 2 infections. 相似文献
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《Remote sensing letters.》2013,4(6):488-497
Mineralogical characteristics of coastal sediments and their spectral characteristics related to moisture content were analysed for South Korea in this study, and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) short-wave infrared (SWIR) remote sensing approaches for moisture content mapping based on conventional SAM module were proposed in this study. The mineral composition included the major minerals of quartz, alkali feldspar, plagioclase and calcite and the accessary minerals of mica and clay. The absorption features of coastal sediments studied occurred at wavelengths of 1.900 μm for clay minerals and water, 2.200 μm for clay minerals and 2.350 μm for micas and calcite. The spectral signature changed with increased moisture content as the absorption feature at 2.200 μm and 2.350 μm faded out. The fading absorption features shifted the resampled laboratory spectra in a spectral vector space and enabled the use of a SAM module for the ASTER SWIR data. The SAM method effectively distinguished not only the absolute moisture content distribution using the reference spectra but also the relative moisture content distribution without the actual reference spectra for coastal sediments. Given that mineral composition and absorption feature behaviours with regard to the moisture content of soil samples are similar to coastal sediments, this method may be applicable for soil moisture mapping. 相似文献
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Dinneen SF Bjornsen SS Bryant SC Zimmerman BR Gorman CA Knudsen JB Rizza RA Smith SA 《Journal of evaluation in clinical practice》2000,6(4):421-429
The objective of the Mayo Health System Diabetes Translation Project is to assess the impact of three different models of care on the overall quality of diabetes care in the community. The unit of study is the primary care practice with a different model of care implemented at each of three sites. The design incorporates a comparison of a diabetes guideline implementation team initiative (Practice model A), a guideline initiative combined with clinical use of a Diabetes Electronic Management System (DEMS) by primary care providers (Practice model B) and a guideline initiative combined with DEMS utilization combined with electronic review of DEMS patient encounters by an endocrinologist (Practice model C). Administrative data sets were used to define the patient population at each practice. Patients were designated as new, attending or non-attending based on their pattern of visits over the preceding 12 months. A random sample of 200 charts from attending patients at each site was audited at baseline for diabetes-related process and outcome measures. This audit will be repeated yearly during the 2 years of the project. Baseline data revealed significant differences across sites in adherence to certain key indicators of the quality of diabetes care including: frequency of documentation of eye examinations (19, 39 and 37% for sites A, B and C, respectively), haemoglobin A1c monitoring (64, 89 and 77%) and microalbumin monitoring (3, 15 and 6%). The interventions being assessed in this study include traditional (diabetes education; guideline implementation) and modern (DEMS; telemedicine specialist review) methods for improving the quality of diabetes care. In spite of variation in baseline quality indicators, the setting and design should lead to broad applicability of the results and help determine an optimal model of diabetes care in the community. 相似文献
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The moisture content of fully cured grass fuel predicted by the original slide rule version of the McArthur Mark V Grassland Fire Danger Meter may differ by up to 3% in oven dry weight from that predicted for equivalent weather conditions by a commonly used equation derived from the meter. The difference between predicted values from the original meter and the equation is greatest at lower air temperatures (≤ 20°C) and when relative humidity is ≥ 40%. This discrepancy is unlikely to result in substantial differences in calculated fire danger indices, but could affect the results of studies attempting to correlate observed fuel moisture contents with predictions from either the original meter or the equation. 相似文献
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Baker RA Zeller RA Klein RL Thornton RJ Shuber JH Marshall RE Leibfarth AG Latko JA 《The Journal of burn care & rehabilitation》2001,22(4):263-268
This study investigated the use of a combination of H1 and H2 antagonists and topical medications to control burn wound itch. Graeco-Latin square assignment provided an oral combination of 1) cetirizine and cimetidine or 2) diphenhydramine and placebo in four divided doses. The study protocol lasted 16 days divided into 4-day intervals, scoring itch before the initial dose of medication and at 1-hour, 6-hour, and 12-hour intervals after the first medication. A significant difference between mean itch scores across the four times was observed (Wilks' Lambda F = 26.52, df = 3, P <.0005). A three-way nested repeated measures interaction effect (Wilks' Lambda F = 9.85, df = 9, P <.0005) was observed representing a significantly different pattern on days 1 to 4 of the study compared with the remaining days. Controlling for the effect of topical medications, the cetirizine/cimetidine combination demonstrated a dramatic improvement at 1 and 6 hours, and a moderate improvement at 12 hours after initial medication for the day when compared with the diphenhydramine/placebo combination. 相似文献
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To measure activities of lactate dehydrogenase (EC 1.1.1.27) isoenzymes LD1 and LD2 in serum, we developed a method involving 1,6-hexanediol as specific inhibitor of the M-subunit. Addition of hexanediol, 0.6 mol/L, to five LD isoenzyme fractions purified from human liver and heart homogenates resulted in complete loss of activities of LD4 and LD5, and partial loss of LD2 and LD3. The activity of LD1, which is composed of the H-subunit only, was not affected. In studying what conditions would allow only the activities of LD1 or LD1 + LD2 to be expressed in serum, we found that the respective activities could be determined by treatment with hexanediol, 0.75 mol/L and 0.55 mol/L, respectively. Results of binding experiments and analytical-recovery tests supported the effectiveness of analyses with this inhibitor in determination of LD1 and LD1 + LD2 activities in serum. Results by this proposed inhibition method correlated well with those by the conventional electrophoretic method for determination of LD1 activity, but LD1 + LD2 activities by the inhibition method were a little less than those by the electrophoretic method, requiring some correction. 相似文献
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H Nielsen F V Mortensen H K Pilegaard J M Hasenkam M J Mulvany 《The Journal of pharmacology and experimental therapeutics》1992,260(2):637-643
Human s.c. resistance arteries (internal diameters 158-353 microns) were mounted in a microvascular myograph, and experiments were designed to examine the calcium pools utilized by selective stimulation of alpha-1 and alpha-2 adrenoceptors. In a concentration-dependent manner, phenylephrine and B-HT 933 evoked contractions mediated by alpha-1 and alpha-2 adrenoceptors, respectively, both in calcium-containing and in calcium-free saline. With respect to the maximum response to potassium in calcium-containing saline, the maximum responses to phenylephrine and B-HT 933 were 96 +/- 6 and 85 +/- 8%, respectively, in calcium-containing saline, and 79 +/- 4 and 14 +/- 2%, respectively, in calcium-free saline. A qualitatively similar difference in maximum responses to alpha-1 vs. alpha-2 adrenoceptor stimulation in calcium-free saline was demonstrated for norepinephrine in the presence of antagonists selective for the two alpha adrenoceptor subtypes. The maximum relaxation in calcium-containing saline produced by the calcium antagonist nitrendipine was 52 +/- 3% in vessels precontracted with phenylephrine, but 80 +/- 5% in vessels precontracted with B-HT 933. A quantitative difference in receptor reserves was demonstrated between alpha-1 and alpha-2 adrenoceptors; 90% of the maximum response was obtained at 34 +/- 5 and 57 +/- 8% receptor occupation, respectively. These data suggest that compared to responses mediated by stimulation of postjunctional alpha-1 adrenoceptors, stimulation of postjunctional alpha-2 adrenoceptors relies heavily on calcium influx. Stimulation of postjunctional alpha-2 adrenoceptors is, however, also coupled to intracellular release of calcium in isolated human s.c. resistance arteries. 相似文献
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Takechi M 《The Journal of international medical research》2004,32(6):655-664
The value of combination therapies that aim to affect both immediate and delayed inflammatory reactions is well known in the treatment of pollinosis. Use of a selective cyclooxygenase-2 (COX-2) inhibitor such as meloxicam is a new approach, however. COX-2 inhibitors target the delayed reaction, which plays a major role in chronic nature of this allergic reaction through activation of the arachidonate cascade and the production of prostaglandins. In this study, four treatment regimens were compared for effectiveness in relieving the symptoms of pollinosis: (i) an anti-allergic alone; (ii) an anti-allergic plus a conventional non-steroidal anti-inflammatory drug; (iii) an anti-allergic plus a selective COX-2 inhibitor; and (iv) an anti-allergic plus an oral steroid. Use of a COX-2 inhibitor plus an anti-allergic produced significantly more relief for most symptoms. The significance of this is as yet unclear, but it is hoped that these results will further our understanding of chronic inflammation. 相似文献
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Glucagon-like peptide-1 (GLP-1) is an incretin hormone that regulates blood glucose level post-prandially. It has been proposed that GLP-1 can be used in type 2 diabetes (T2D) mellitus treatment because of its insulinotropic action. Despite its remarkable advantages, GLP-1 suffers the disadvantage of an extremely short half-life owing to its degradation by the dipeptidyl peptidase IV protease. One way of overcoming this drawback is GLP-1 gene delivery. Here we show effective and safe gene-based delivery of GLP-1 using chitosan/plasmid-DNA therapeutic nanocomplexes (TNCs) in Zucker diabetic fatty (ZDF) animal model of T2D. The expression plasmid fused the GLP-1 gene to a Furin cleavage site was driven by a cytomegalovirus promoter/enhancer. TNCs were prepared by mixing this plasmid with chitosans of specific molecular weight (MW), degree of deacetylation (DDA) and ratio of chitosan amine to DNA phosphate (N:P ratio). Animals injected with the TNC chitosan 92-10-5 (DDA-MW-N:P) showed GLP-1 plasma levels of about fivefold higher than that in non-treated animals and the insulinotropic effect of recombinant GLP-1 was shown by a threefold increase in plasma insulin concentration when compared with untreated animals. Intraperitoneal glucose tolerance tests revealed an efficacious decrease of blood glucose compared with controls for up to 24 days after treatment, where injections of this formulation allowed near-normalization of blood glucose level. TNCs composed of specific chitosans and GLP-1-expressing plasmid constructs showed an impressive ability to harness the profound therapeutic potential of GLP-1 for the treatment of T2D mellitus. 相似文献
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Baojun Wei Yuxiang Wei Kuo Zhang Jing Wang Ruihuan Xu Sien Zhan Guigao Lin Wei Wang Min Liu Lunan Wang Rui Zhang Jinming Li 《Biomedicine & Pharmacotherapy》2009
RNA-based therapeutic strategies are used widely due to their highly specific mode of action. However, the major obstacle in any RNA-based therapy is cellular delivery and stability in the cells. The self-assembly of the MS2 bacteriophage capsids has been used to develop virus-like particles (VLPs) for drug delivery. In this study, we utilized the heterobifunctional crosslinker, sulfosuccinimidyl-4-(p-maleimidophenyl)-butyrate (sulfo-SMPB), to conjugate the human immunodeficiency virus-1 (HIV-1) Tat peptide and MS2 VLPs; the antisense RNA against the 5′-untranslated region (UTR) and the internal ribosome entry site (IRES) of the hepatitis C virus (HCV) was packaged into these particles by using a two-plasmid coexpression system. The MS2 VLPs conjugated with the Tat peptide were then transferred into Huh-7 cells containing an HCV reporter system. The packaged antisense RNA showed an inhibitory effect on the translation of HCV. This paper describes our initial results with this system using the Tat peptide. 相似文献
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Ramachandran A Riddle MC Kabali C Gerstein HC;ORIGIN Investigators 《Diabetes care》2012,35(4):749-753
OBJECTIVE
A1C measurement has advantages over measures of plasma glucose. Few studies have evaluated the A1C–fasting plasma glucose (FPG) relationship and whether oral antidiabetes drugs (OADs) and ethnic or geographic variations affect the relationship. Baseline A1C and FPG data from the Outcome Reduction with Initial Glargine Intervention (ORIGIN) trial participants were analyzed to 1) elucidate the relationship between A1C and FPG in people with moderate dysglycemia (A1C 5.6–9.0% [38–75 mmol/mol]) and additional risk factors for cardiovascular disease, 2) determine whether this relationship is altered by use of an OAD, and 3) study whether geographic and ethnic differences exist.RESEARCH DESIGN AND METHODS
Analysis was performed of 12,527 participants with dysglycemia or early type 2 diabetes recruited in North America, South America, Europe, Australia, and Asia who comprised white, Latin American, Asian, black, and other ethnicities. The A1C-FPG relationships were analyzed using cubic B spline curves in all participants and in subgroups not using an OAD or using an OAD and comprising persons of different ethnic or geographic origin.RESULTS
A strong relationship between FPG in the range of 5.6–9.0 mmol/L and the corresponding A1C was seen across different geographic regions and ethnic groups. A smaller increase in A1C per unit increase in FPG occurred for persons taking an OAD versus those not taking an OAD.CONCLUSIONS
The strong relationship between A1C and FPG in moderate dysglycemia is not significantly affected by ethnic or geographic differences. Use of an OAD alters the relationship and should be considered when interpreting A1C level.A1C is widely used in the management of diabetes both as a measure of long-term glycemic control and as a risk factor for diabetes complications (1–3). Many studies have demonstrated that A1C is correlated with and reflects other measures of glycemic control including FPG and 2-h plasma glucose (4,5). A1C has several advantages over direct measures of plasma glucose including greater reproducibility and sample stability, less intrapersonal variation, and measurability in random versus fasting or postprandial blood samples (6,7). Limitations of A1C as a measure of glycemic control include genetically determined variations of hemoglobin structure that may alter the rate of glycation of the molecule or the lifespan of erythrocytes, thus altering the relationship between glucose and A1C. These observations, together with known ethnic and regional variations of dietary habits, suggest that A1C and glucose levels may differ by ethnicity (8–10) or geographic location (11). However, little is known about the relationship between A1C and glucose levels in different populations. Furthermore, few studies have evaluated whether the relationship between A1C and glucose levels is affected by the use of glucose-lowering agents (4,8,12).The Outcome Reduction with Initial Glargine Intervention (ORIGIN) trial is a global trial testing whether targeting normal FPG levels with basal insulin glargine reduces cardiovascular outcomes compared with standard care in people taking 0 or 1 oral antidiabetes drugs (OADs) (13). Baseline A1C and FPG data collected from participants were analyzed in order to 1) elucidate the relationship between A1C and FPG in persons with moderate dysglycemia (A1C 5.6–9.0% [38–75 mmol/mol]) and additional risk factors for cardiovascular disease, 2) determine whether this relationship is altered by use of an OAD, and 3) study whether the relationship differs in persons from different geographic regions or of different ethnicity. 相似文献17.
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Jian-Jun Wang Guisheng Zhou Yun Zhang Coen Bussink Jiahua Zhang Hao Ge 《Remote sensing letters.》2016,7(10):945-954
Remote sensing has special advantages to monitor drug production that causes serious problems to global society. The widely used high spatial resolution images are too costly to make the full coverage of the opium poppy fields in a large area. Although the hyperspectral imagery acquired by Earth Observing-1 (EO-1) Hyperion that is free with medium spatial resolution has been employed, the used unsupervised multiple endmember spectral mixture analysis (MESMA)-based method is time-consuming for a large area. The present study used an unsupervised mixture-tuned matched filtering (MTMF)-based method to detect poppy fields from a Hyperion image covering a study area in Helmand, Afghanistan, and it achieved the producer’s, user’s and overall accuracies of 61%, 73% and 76%, as well as the kappa coefficient of 0.48. This method worked over 10 times faster than the MESMA-based method with similar detection accuracies. This MTMF-based method provides a potential alternative for the United Nations and the Afghanistan government to monitor opium poppy cultivation in Afghanistan. 相似文献
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Serrano-Rubio LE Tenorio-Gutiérrez V Suárez-Güemes F Reyes-Cortés R Rodríguez-Mendiola M Arias-Castro C Godínez-Vargas D de la Garza M 《Molecular and cellular probes》2008,22(5-6):305-312
Actinobacillus pleuropneumoniae causes swine pleuropneumonia worldwide. Previously, we described a gene sequence of approximately 800bp in A. pleuropneumoniae serotype 1 that encodes a metalloprotease of 24kDa, (Genbank accession no. AY217757). We selected primers carrying the forward and reverse 5'-terminal sequences of this region of the gene for the development of a species-specific PCR assay. The primers amplified an 800bp sequence from isolated DNA and lysed bacteria of the 13 A. pleuropneumoniae biovar 1 serotypes, with the exception of subtype 1b. The primers also amplified the sequence in nasal secretion cultures from pigs with chronic and acute experimental pleuropneumonia. No PCR products were detected when A. pleuropneumoniae serotypes of biovar 2 were used. Internal primers from this gene sequence detected biovar 2 and subtype 1b, leading to the production of a 350bp PCR product. The primers did not amplify DNA from other related species from the Pasteurellaceae family. The 800bp PCR assay was sensitive in vitro, with a detection limit of 5.5pg of extracted DNA, and an average of 120CFU. The specificity and sensitivity of this PCR assay make it a useful method for the rapid identification and diagnosis of A. pleuropneumoniae. 相似文献
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Multimodal imaging improves the accuracy of the localization and the quantification of brain activation when measuring different manifestations of the hemodynamic response associated with cerebral activity. In this study, we incorporated cerebral blood flow (CBF) changes measured with arterial spin labeling (ASL), Diffuse Optical Tomography (DOT) and blood oxygen level-dependent (BOLD) recordings to reconstruct changes in oxy- (ΔHbO(2)) and deoxyhemoglobin (ΔHbR). Using the Grubb relation between relative changes in CBF and cerebral blood volume (CBV), we incorporated the ASL measurement as a prior to the total hemoglobin concentration change (ΔHbT). We applied this ASL fusion model to both synthetic data and experimental multimodal recordings during a 2-s finger-tapping task. Our results show that the new approach is very powerful in estimating ΔHbO(2) and ΔHbR with high spatial and quantitative accuracy. Moreover, our approach allows the computation of baseline total hemoglobin concentration (HbT(0)) as well as of the BOLD calibration factor M on a single subject basis. We obtained an average HbT(0) of 71 μM, an average M value of 0.18 and an average increase of 13% in cerebral metabolic rate of oxygen (CMRO(2)), all of which are in agreement with values previously reported in the literature. Our method yields an independent measurement of M, which provides an alternative measurement to validate the hypercapnic calibration of the BOLD signal. 相似文献