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Authors = Chunhua Zhang ORCID = 0000-0001-6685-0137

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Open AccessArticle Examining the Influence of Seasonality, Condition, and Species Composition on Mangrove Leaf Pigment Contents and Laboratory Based Spectroscopy Data
Remote Sens. 2016, 8(3), 226; doi:10.3390/rs8030226
Received: 20 January 2016 / Revised: 29 February 2016 / Accepted: 7 March 2016 / Published: 10 March 2016
Cited by 2 | Viewed by 970 | PDF Full-text (5522 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this investigation was to determine the seasonal relationships (dry vs. rainy) between reflectance (400–1000 nm) and leaf pigment contents (chlorophyll-a (chl-a), chlorophyll-b (chl-b), total carotenoids (tcar), chlorophyll a/b ratio) in three mangrove species (Avicennia germinans (A. germinans),
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The purpose of this investigation was to determine the seasonal relationships (dry vs. rainy) between reflectance (400–1000 nm) and leaf pigment contents (chlorophyll-a (chl-a), chlorophyll-b (chl-b), total carotenoids (tcar), chlorophyll a/b ratio) in three mangrove species (Avicennia germinans (A. germinans), Laguncularia racemosa (L. racemosa), and Rhizophora mangle (R. mangle)) according to their condition (stressed vs. healthy). Based on a sample of 360 leaves taken from a semi-arid forest of the Mexican Pacific, it was determined that during the dry season, the stressed A. germinans and R. mangle show the highest maximum correlations at the green (550 nm) and red-edge (710 nm) wavelengths (r = 0.8 and 0.9, respectively) for both chl-a and chl-b and that much lower values (r = 0.7 and 0.8, respectively) were recorded during the rainy season. Moreover, it was found that the tcar correlation pattern across the electromagnetic spectrum was quite different from that of the chl-a, the chl-b, and chl a/b ratio but that their maximum correlations were also located at the same two wavelength ranges for both seasons. The stressed L. racemosa was the only sample to exhibit minimal correlation with chl-a and chl-b for either season. In addition, the healthy A. germinans and R. mangle depicted similar patterns of chl-a and chl-b, but the tcar varied depending on the species. The healthy L. racemosa recorded higher correlations with chl-b and tcar at the green and red-edge wavelengths during the dry season, and higher correlation with chl-a during the rainy season. Finally, the vegetation index Red Edge Inflection Point Index (REIP) was found to be the optimal index for chl-a estimation for both stressed and healthy classes. For chl-b, both the REIP and the Vogelmann Red Edge Index (Vog1) index were found to be best at prediction. Based on the results of this investigation, it is suggested that caution be taken as mangrove leaf pigment contents from spectroscopy data have been shown to be sensitive to seasonality, species, and condition. The authors suggest potential reasons for the observed variability in the reflectance and pigment contents relationships. Full article
(This article belongs to the Special Issue Remote Sensing in Coastal Environments)
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Open AccessArticle Spatio-Temporal Variation and Impact Factors for Vegetation Carbon Sequestration and Oxygen Production Based on Rocky Desertification Control in the Karst Region of Southwest China
Remote Sens. 2016, 8(2), 102; doi:10.3390/rs8020102
Received: 30 September 2015 / Revised: 19 January 2016 / Accepted: 20 January 2016 / Published: 28 January 2016
Cited by 1 | Viewed by 993 | PDF Full-text (4396 KB) | HTML Full-text | XML Full-text
Abstract
The Grain to Green Program (GTGP) and eco-environmental emigration have been employed to alleviate poverty and control rocky desertification in the Southwest China Karst region. Carbon sequestration and oxygen production (CSOP) is used to indicate major ecological changes, because they involve complex processes
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The Grain to Green Program (GTGP) and eco-environmental emigration have been employed to alleviate poverty and control rocky desertification in the Southwest China Karst region. Carbon sequestration and oxygen production (CSOP) is used to indicate major ecological changes, because they involve complex processes of material circulation and energy flow. Using remote sensing images and weather records, the spatiotemporal variation of CSOP was analyzed in a typical karst region of northwest Guangxi, China, during 2000–2010 to determine the effects of the Chinese government’s ecological rehabilitation initiatives implemented in 1999. An increase with substantial annual change and a significant increase (20.94%, p < 0.05) in variation were found from 2000 to 2010. CSOP had a highly clustered distribution in 2010 and was correlated with precipitation and temperature (9.18% and 8.96%, respectively, p < 0.05). CSOP was significantly suppressed by human activities (p < 0.01, r = −0.102) but was consistent with the intensity of GTGP (43.80% positive). The power spectrum of CSOP was consistent with that of the gross domestic product. These results indicate that ecological services were improved by rocky desertification control in a typical karst region. The results may provide information to evaluate the efficiency of ecological reconstruction projects. Full article
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Open AccessArticle Altered Pre-mRNA Splicing Caused by a Novel Intronic Mutation c.1443+5G>A in the Dihydropyrimidinase (DPYS) Gene
Int. J. Mol. Sci. 2016, 17(1), 86; doi:10.3390/ijms17010086
Received: 20 November 2015 / Revised: 28 December 2015 / Accepted: 4 January 2016 / Published: 12 January 2016
Cited by 1 | Viewed by 913 | PDF Full-text (2124 KB) | HTML Full-text | XML Full-text
Abstract
Dihydropyrimidinase (DHP) deficiency is an autosomal recessive disease caused by mutations in the DPYS gene. Patients present with highly elevated levels of dihydrouracil and dihydrothymine in their urine, blood and cerebrospinal fluid. The analysis of the effect of mutations in DPYS on pre-mRNA
[...] Read more.
Dihydropyrimidinase (DHP) deficiency is an autosomal recessive disease caused by mutations in the DPYS gene. Patients present with highly elevated levels of dihydrouracil and dihydrothymine in their urine, blood and cerebrospinal fluid. The analysis of the effect of mutations in DPYS on pre-mRNA splicing is hampered by the fact that DHP is primarily expressed in liver and kidney cells. The minigene approach can detect mRNA splicing aberrations using cells that do not express the endogenous mRNA. We have used a minigene-based approach to analyze the effects of a presumptive pre-mRNA splicing mutation in two newly identified Chinese pediatric patients with DHP deficiency. Mutation analysis of DPYS showed that both patients were compound heterozygous for a novel intronic mutation c.1443+5G>A in intron 8 and a previously described missense mutation c.1001A>G (p.Q334R) in exon 6. Wild-type and the mutated minigene constructs, containing exons 7, 8 and 9 of DPYS, yielded different splicing products after expression in HEK293 cells. The c.1443+5G>A mutation resulted in altered pre-mRNA splicing of the DPYS minigene construct with full skipping of exon 8. Analysis of the DHP crystal structure showed that the deletion of exon 8 severely affects folding, stability and homooligomerization of the enzyme as well as disruption of the catalytic site. Thus, the analysis suggests that the c.1443+5G>A mutation results in aberrant splicing of the pre-mRNA encoding DHP, underlying the DHP deficiency in two unrelated Chinese patients. Full article
(This article belongs to the Special Issue Pre-mRNA Splicing 2015)
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Open AccessReview Molecular Composition of Plant Vacuoles: Important but Less Understood Regulations and Roles of Tonoplast Lipids
Plants 2015, 4(2), 320-333; doi:10.3390/plants4020320
Received: 24 March 2015 / Revised: 21 May 2015 / Accepted: 3 June 2015 / Published: 11 June 2015
Cited by 4 | Viewed by 1212 | PDF Full-text (405 KB) | HTML Full-text | XML Full-text
Abstract
The vacuole is an essential organelle for plant growth and development. It is the location for the storage of nutrients; such as sugars and proteins; and other metabolic products. Understanding the mechanisms of vacuolar trafficking and molecule transport across the vacuolar membrane is
[...] Read more.
The vacuole is an essential organelle for plant growth and development. It is the location for the storage of nutrients; such as sugars and proteins; and other metabolic products. Understanding the mechanisms of vacuolar trafficking and molecule transport across the vacuolar membrane is of great importance in understanding basic plant development and cell biology and for crop quality improvement. Proteins play important roles in vacuolar trafficking; such proteins include Rab GTPase signaling proteins; cargo recognition receptors; and SNAREs (Soluble NSF Attachment Protein Receptors) that are involved in membrane fusion. Some vacuole membrane proteins also serve as the transporters or channels for transport across the tonoplast. Less understood but critical are the roles of lipids in vacuolar trafficking. In this review, we will first summarize molecular composition of plant vacuoles and we will then discuss our latest understanding on the role of lipids in plant vacuolar trafficking and a surprising connection to ribosome function through the study of ribosomal mutants. Full article
(This article belongs to the Special Issue Plant Vacuole)
Open AccessArticle Separating Mangrove Species and Conditions Using Laboratory Hyperspectral Data: A Case Study of a Degraded Mangrove Forest of the Mexican Pacific
Remote Sens. 2014, 6(12), 11673-11688; doi:10.3390/rs61211673
Received: 19 August 2014 / Revised: 18 November 2014 / Accepted: 19 November 2014 / Published: 25 November 2014
Cited by 8 | Viewed by 1993 | PDF Full-text (2704 KB) | HTML Full-text | XML Full-text
Abstract
Given the scale and rate of mangrove loss globally, it is increasingly important to map and monitor mangrove forest health in a timely fashion. This study aims to identify the conditions of mangroves in a coastal lagoon south of the city of Mazatlán,
[...] Read more.
Given the scale and rate of mangrove loss globally, it is increasingly important to map and monitor mangrove forest health in a timely fashion. This study aims to identify the conditions of mangroves in a coastal lagoon south of the city of Mazatlán, Mexico, using proximal hyperspectral remote sensing techniques. The dominant mangrove species in this area includes the red (Rhizophora mangle), the black (Avicennia germinans) and the white (Laguncularia racemosa) mangrove. Moreover, large patches of poor condition black and red mangrove and healthy dwarf black mangrove are commonly found. Mangrove leaves were collected from this forest representing all of the aforementioned species and conditions. The leaves were then transported to a laboratory for spectral measurements using an ASD FieldSpec® 3 JR spectroradiometer (Analytical Spectral Devices, Inc., USA). R2 plot, principal components analysis and stepwise discriminant analyses were then used to select wavebands deemed most appropriate for further mangrove classification. Specifically, the wavebands at 520, 560, 650, 710, 760, 2100 and 2230 nm were selected, which correspond to chlorophyll absorption, red edge, starch, cellulose, nitrogen and protein regions of the spectrum. The classification and validation indicate that these wavebands are capable of identifying mangrove species and mangrove conditions common to this degraded forest with an overall accuracy and Khat coefficient higher than 90% and 0.9, respectively. Although lower in accuracy, the classifications of the stressed (poor condition and dwarf) mangroves were found to be satisfactory with accuracies higher than 80%. The results of this study indicate that it could be possible to apply laboratory hyperspectral data for classifying mangroves, not only at the species level, but also according to their health conditions. Full article
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Open AccessArticle Initial Study on Triaxiality of Human Settlements—In the Case of 10 Districts (Counties) of Dalian
Sustainability 2014, 6(10), 7276-7291; doi:10.3390/su6107276
Received: 15 August 2014 / Revised: 12 October 2014 / Accepted: 13 October 2014 / Published: 22 October 2014
Cited by 1 | Viewed by 1320 | PDF Full-text (1843 KB) | HTML Full-text | XML Full-text
Abstract
For a long time, the traditional pattern of urban-rural human settlements has been shaped in reference to the existence of the urban-rural dual structure. In this paper, we put forward the notion of triaxiality of human settlements, and used the standards conversion entropy
[...] Read more.
For a long time, the traditional pattern of urban-rural human settlements has been shaped in reference to the existence of the urban-rural dual structure. In this paper, we put forward the notion of triaxiality of human settlements, and used the standards conversion entropy weight method to measure and calculate degrees of livability of human settlements, so as to prove the existence of triaxiality of human settlements within the same unit at the micro-scale level, and conduct an empirical study on the spatial-temporal evolution, system attributes and formation mechanisms of the triaxiality of human settlements in 10 districts (counties) of Dalian (Years 2002–2011). Results showed that: (1) Spatial evolution of human settlements presents triaxiality. Administrative divisions do not play a full and predominant role in the unit division of human settlements. The number of distribution districts (counties) within different units of human settlements tends to be balanced, there is spatial variation of tertiary units in the human settlements of Dalian, and the transition area of human settlements occupies the leading position in the unit division of human settlements; (2) Human settlements also exhibit triaxiality at different development stages during the period of evolution. The fluctuation changes of degrees of livability of the human settlements of Dalian within the past 10 years have been relatively stable, with a trend of small scale decline and obvious manifestations of stage differences; (3) The system attributive characters of human settlements presents triaxiality. There also exists differentiations of system and area in human settlements within the same unit; (4) Industrialization and urbanization have led to the collapse of part of the urban-rural dual structure, while the differentiation of ternary structure of the economic and social structure, and living environment and life style leads to the triaxiality of human settlements. Full article
Open AccessArticle Separating Crop Species in Northeastern Ontario Using Hyperspectral Data
Remote Sens. 2014, 6(2), 925-945; doi:10.3390/rs6020925
Received: 23 October 2013 / Revised: 9 January 2014 / Accepted: 16 January 2014 / Published: 24 January 2014
Cited by 8 | Viewed by 2553 | PDF Full-text (1428 KB) | HTML Full-text | XML Full-text
Abstract
The purpose of this study was to examine the capability of hyperspectral narrow wavebands within the 400–900 nm range for distinguishing five cash crops commonly grown in Northeastern Ontario, Canada. Data were collected from ten different fields in the West Nipissing agricultural zone
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The purpose of this study was to examine the capability of hyperspectral narrow wavebands within the 400–900 nm range for distinguishing five cash crops commonly grown in Northeastern Ontario, Canada. Data were collected from ten different fields in the West Nipissing agricultural zone (46°24'N lat., 80°07'W long.) and included two of each of the following crop types; soybean (Glycine max), canola (Brassica napus L.), wheat (Triticum spp.), oat (Avena sativa), and barley (Hordeum vulgare). Stepwise discriminant analysis was used to assess the spectral separability of the various crop types under two scenarios; Scenario 1 involved testing separability of crops based on number of days after planting and Scenario 2 involved testing crop separability at specific dates across the growing season. The results indicate that select hyperspectral bands in the visual and near infrared (NIR) regions (400–900 nm) can be used to effectively distinguish the five crop species under investigation. These bands, which were used in a variety of combinations include B465, B485, B495, B515, B525, B535, B545, B625, B645, B665, B675, B695, B705, B715, B725, B735, B745, B755, B765, B815, B825, B885, and B895. In addition, although species classification could be achieved at any point during the growing season, the optimal time for satellite image acquisition was determined to be in late July or approximately 75–79 days after planting with the optimal wavebands located in the red-edge, green, and NIR regions of the spectrum. Full article
Open AccessArticle Relationship between Hyperspectral Measurements and Mangrove Leaf Nitrogen Concentrations
Remote Sens. 2013, 5(2), 891-908; doi:10.3390/rs5020891
Received: 20 December 2012 / Revised: 6 February 2013 / Accepted: 16 February 2013 / Published: 22 February 2013
Cited by 10 | Viewed by 2437 | PDF Full-text (3031 KB) | HTML Full-text | XML Full-text
Abstract
The use of spectral response curves for estimating nitrogen (N) leaf concentrations generally has been found to be a challenging task for a variety of plant species. In this investigation, leaf N concentration and corresponding laboratory hyperspectral data were examined for two species
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The use of spectral response curves for estimating nitrogen (N) leaf concentrations generally has been found to be a challenging task for a variety of plant species. In this investigation, leaf N concentration and corresponding laboratory hyperspectral data were examined for two species of mangrove (Avicennia germinans, Rhizophora mangle) representing a variety of conditions (healthy, poor condition, dwarf) of a degraded mangrove forest located in the Mexican Pacific. This is the first time leaf nitrogen content has been examined using close range hyperspectral remote sensing of a degraded mangrove forest. Simple comparisons between individual wavebands and N concentrations were examined, as well as two models employed to predict N concentrations based on multiple wavebands. For one model, an Artificial Neural Network (ANN) was developed based on known N absorption bands. For comparative purposes, a second model, based on the well-known Stepwise Multiple Linear Regression (SMLR) approach, was employed using the entire dataset. For both models, the input data included continuum removed reflectance, band depth at the centre of the absorption feature (BNC), and log (1/BNC). Weak to moderate correlations were found between N concentration and single band spectral responses. The results also indicate that ANNs were more predictive for N concentration than was SMLR, and had consistently higher r2 values. The highest r2 value (0.91) was observed in the prediction of black mangrove (A. germinans) leaf N concentration using the BNC transformation. It is thus suggested that artificial neural networks could be used in a complementary manner with other techniques to assess mangrove health, thereby improving environmental monitoring in coastal wetlands, which is of prime importance to local communities. In addition, it is recommended that the BNC transformation be used on the input for such N concentration prediction models. Full article
Open AccessArticle A Simple and Efficient Route for Preparing 2,3,5,6-Tetraaminopyridine Hydrochloride Salt
Molecules 2009, 14(5), 1652-1659; doi:10.3390/molecules14051652
Received: 25 March 2009 / Revised: 10 April 2009 / Accepted: 15 April 2009 / Published: 27 April 2009
Cited by 3 | Viewed by 5205 | PDF Full-text (225 KB)
Abstract
A simple and efficient route for preparing 2,3,5,6-tetraaminopyridine hydrochloride salt (TAP·3HCl·H2O) was introduced in this paper. The title compound was synthesized, as usual, in two steps (nitration and hydrogenation) with a total yield of 90%. The use of an oleum and
[...] Read more.
A simple and efficient route for preparing 2,3,5,6-tetraaminopyridine hydrochloride salt (TAP·3HCl·H2O) was introduced in this paper. The title compound was synthesized, as usual, in two steps (nitration and hydrogenation) with a total yield of 90%. The use of an oleum and fuming nitric acid mixture in the nitration step improved the yield and purity of the intermediate product. A highly efficient hydrogenation using a H2/Pd/C/C2H5OH system was developed. The products were characterized by TG, IR, 1H-NMR, 13C-NMR, HPLC and elemental analysis. Full article

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