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1.
Ying Yong Sheng Tai Xue Bao ; 30(10): 3491-3500, 2019 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-31621236

RESUMO

The dynamic simulation of cucumber growth and development in sunlight greenhouse can provide technical support for the intelligent management of cucumber production. According to the cucumber response characteristics to light and temperature, the cucumber development module based on the algorithm of clock model was established by using data from four-stage experiment with 'Jinyou 35' as experiment variety in two years. Based on the relationship between the leaf growth and key meteorological factors (temperature and radiation), leaf area index (LAI) module was established with the accumulated product of thermal effectiveness and photosynthetically active radiation (TEP) as independent variables. The simulation module of cucumber dry matter production was established by taking into consideration the double integral of LAI and daily length in photosynthesis per unit leaf area as well as the respiratory expenditure of different organs. Combined with water content of organs, fresh weight simulation module of cucumber organs was constructed. The whole cucumber development and growth simulation model in greenhouse was built based on each sub-module. The model parameters were calibrated and determined. The results showed that root mean square error (RMSE) of simulated values and observed values of four deve-lopment stages (from transplanting date to stretch tendril, to initial flowering, to early harvested and to uprooting), was 3.9-10.5 d. The normalized root mean square error (nRMSE) was 6.5%-28.6%. The coincidence index (D) was 0.79-0.97. The relationship between LAI and TEP was the regression of 'S' type curve. The RMSE of simulated and observed LAI values was 0.19. The nRMSE was 17.2%. The D value was 0.90. The RMSE of dry weight of root, stem, leaf, flower and fruit of the simulated values and observed values were 0.39-8.94 g·m-2. The nRMSE were 10.9%-17.7%. The D values were all above 0.98. The growth and development model of cucumber could accurately simulate the key development period of cucumber, leaf area and the dry and fresh weight of various organs and quantify the growth and development of cucumber in sunlight greenhouse.


Assuntos
Cucumis sativus , Crescimento e Desenvolvimento , Fotossíntese , Folhas de Planta , Luz Solar
2.
Lancet ; 394(10208): 1518, 2019 10 26.
Artigo em Inglês | MEDLINE | ID: mdl-31657731
3.
An Acad Bras Cienc ; 91(3): e20180066, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31508663

RESUMO

Despite its economic importance, the microclimate in soybean canopies has not yet been studied in detail. Such a study can yield valuable information regarding the interaction of a crop with its environment. In this context, the aim of this study was to evaluate the solar radiation dynamic and yield responses for each canopy strata for two soybean cultivars with determined and undetermined growth habits. A field study was conducted during the 2013/2014 and 2014/2015 growing seasons in the city of Frederico Westphalen, Rio Grande do Sul, Brazil. The cultivar NA6411, with a determinate growth habit, presented a greater interception of radiation in the middle and lower canopies strata which results in higher soybean yield when compared to the cultivar TEC6029, and thus, can be recommended for cultivation in crop production systems. The contribution of the middle and upper canopy strata to the total yield formation was greater than that observed in the lower canopy strata due to the greater interception of solar radiation by these strata. To increase soybean yields, new studies regarding the microclimatic conditions of the soybean canopy should be developed to improve the maximum potential yield of the new soybean cultivars.


Assuntos
Microclima , Soja/crescimento & desenvolvimento , Soja/efeitos da radiação , Luz Solar , Agricultura/métodos , Brasil
4.
J Environ Manage ; 250: 109462, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31472372

RESUMO

Preparation of active photocatalytic nanostructures to harvest the abundant sunlight energy is a recent worldwide direction for clean energy production and environmental management. Following this target, different calcium carbonate-titania nanostructures were prepared by three different pathways using available raw materials such as limestone as calcium precursor. After characterization of the prepared materials with X-ray diffraction (XRD), X-ray fluorescence (XRF) patterns, Fourier transmission infrared (FT-IR), high resolution transmission electron microscope (TEM), N2 adsorption-desorption isotherm, UV-vis diffuse reflectance and photoluminance (PL), the materials were applied as novel photocatalysts for desulfurization of dibenzothiophene (DBT) and gas oil using different radiation sources at room temperature. It has been obtained that, 95% desulfurization of DBT was possible under 1 h visible light irradiation with linear halogen lamp (LHL) at catalyst/DBT-solution = 10 g/L, while ultra-clean diesel production (99% removal, 3.47 ppm) could be obtained via normal sunlight photochemical desulfurization of diesel fuel by calcium carbonate titania photocatalyst in presence of H2O2 and acetic acid as oxidizing agents and acetonitrile as a solvent. Here, the followed preparation pathway produced highly active calcium titanate photocatalysts with tunable band gap energy (2.05 eV), reduced electrons/hole pairs recombination and stable photocatalytic activity with enhanced visible light removal of organosulfur compounds for economic ultra-clean fuel production, pollution control, and environmental management.


Assuntos
Nanocompostos , Carbonato de Cálcio , Catálise , Conservação dos Recursos Naturais , Peróxido de Hidrogênio , Luz , Espectroscopia de Infravermelho com Transformada de Fourier , Luz Solar , Titânio , Difração de Raios X
5.
Ying Yong Sheng Tai Xue Bao ; 30(9): 2941-2948, 2019 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-31529868

RESUMO

To explore the photosynthetic adaptation of Phoebe bournei to different light conditions, two-year-old P. bournei seedlings were grown under three light regimes (full light, shading rate 50% and 78% of full light). The chlorophyll contents, leaf gas exchange and chlorophyll fluorescence of P. bournei were measured after six-month treatment. The results showed that the contents of chlorophyll a, chlorophyll b, chlorophyll (a+b) and carotenoids in leaves were in a descending order of shading rate 78% > shading rate 50% > full light. There was no significant difference of chlorophyll a/b between natural and shade treatments. The shading treatment reduced light compensation point (LCP), but increased light saturation point (LSP) and apparent quantum yield (AQY), suggesting that plants could utilize both the weak light and the high light. Maximum net photosynthetic rate (Pn max), dark respiration rate (Rd), and maximum electron transfer rate (Jmax) increased under the shading treatment. There was significant difference between natural and shade treatment in net photosynthetic rate (Pn), stomatal conductance to CO2(gsc), intercellular CO2 concentration (Ci), and mesophyll conductance (gm). Pn and gm of different light regimes were sorted from the highest to the lowest as shading rate 78% > shading rate 50% > full light. gsc under shading rate 78% was higher than that under full light. Ci under shading rate 50% and 78% were lower than that under full light. Actual photochemical efficiency of PS2 (Fv'/Fm'), quantum yields of PS2 (ΦPS2), and electron transport rate (J) of P. bournei leaves were significantly higher under shading rate 78% than those under shading rate 50% and full light. In conclusion, P. bournei could increase Pn by increasing chlorophyll content, AQY, J, gsc, and gm under shade condition.


Assuntos
Clorofila/metabolismo , Lauraceae/fisiologia , Folhas de Planta/metabolismo , Clorofila/análise , Clorofila A , Fotossíntese/fisiologia , Folhas de Planta/química , Plântula , Luz Solar
6.
J Cosmet Sci ; 70(4): 181-196, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31441772

RESUMO

In the original scientific publication evaluating sunscreen methodologies, Garzarella and Caswell showed there to be no clinically significant or statistically significant difference in the average Sun Protection Factor (SPF) of a sunscreen formulation between any of three methodologies, Food and Drug Administration (FDA) Final Monograph, Australia/New Zealand, and European Cosmetics Association (COLIPA) International, suggesting that any differences in methodology were insignificant in the resulting SPF determined. These three major older methodologies have coalesced into two methodologies, 2011 FDA-Final Rule and ISO 24444, so that current sunscreen SPF testing is mostly 2011 FDA-Final Rule and ISO 24444. Another approach to evaluating the impact of methodological differences in sunscreen testing is to compare data on a control standard or reference sunscreen. If the difference between the two SPF values of P2 is statistically significant for the two different methodologies, then this would present evidence for a clinically significant difference in the SPF value between the two methodologies. For 2011 FDA-Final Rule, the expected SPF of P2 is 16.3 ± 3.43; for ISO 24444, the expected SPF of P2 is 16.1 ± 2.42. Using least squares average and standard error on 952 observations, the 2011 FDA-Final Rule SPF of P2 is 15.4 ± 0.12; using least squares average and standard error on 1,551 observations, the ISO 24444 SPF of P2 is 15.6 ± 0.10. The data described herein indicate no clinically significant nor statistically significant difference between the SPF average of P2 using the 2011 FDA-Final Rule methodology versus that using ISO 24444 methodology. Further statistical analysis indicates that the average SPF of P2 is independent of solar simulator type, time of year (month), age of subject, gender of subject, or Fitzpatrick Skin Phototype of subject. A statistically significant negative correlation was found between a subject's SPF of P2 and the subject's unprotected minimal erythemal dose. The implications of this relationship on SPF testing are explored.


Assuntos
Cosméticos , Fator de Proteção Solar , Humanos , Luz Solar , Protetores Solares , Raios Ultravioleta , Estados Unidos , United States Food and Drug Administration
7.
Ying Yong Sheng Tai Xue Bao ; 30(8): 2725-2736, 2019 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-31418198

RESUMO

Decrease in solar radiation is one of the main components of climate change. Studies aimed at examining the effects of decreased solar radiation on CH4 emission and estimation of CH4 emission based on hyperspectral data in paddy fields are still scarce. A field simulation experiment was conducted to investigate the effects of shading intensity on CH4 emission in a paddy field and rice canopy hyperspectral properties. CH4 emission flux was estimated with rice canopy hyperspectral data. The shading intensities were set at three levels, i.e. control (CK, no shading), light shading (S1, 60% of shading rate), and heavy shading (S2, 84% of shading rate). The results showed that shading significantly reduced CH4 emission. However, CH4 emission under heavy shading (S2) was higher than that under light shading (S1). The reflectance of the near-infrared spectrum on rice canopy from the jointing stage to grain filling stage was in the sequence of CK>S2>S1. The spectral reflectance on rice canopy was significantly and positively correlated with CH4 flux in the near-infrared band (699-1349 nm), with a correlation coefficient of 0.64 (P<0.01). The six vegetation indices were significantly correlated with CH4 flux. The correlation coefficient between Ratio Vegetation Index (RVI) and CH4 flux was the largest, with R2=0.84 (P<0.01). The stepwise regression model with RVI, Normalized Difference Vegetation Index (NDVI), and 507 nm original reflectance (Ρ507) parameters was the best one (fitting model R2=0.86, prediction model R2=0.85) for estimating CH4 emission.


Assuntos
Metano/análise , Oryza , Luz Solar
8.
J Environ Manage ; 249: 109348, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31430624

RESUMO

This work evaluates the feasibility of a solar-enhanced Fenton-like process using S2O82- (PS) and Fe2+ for the elimination of BPA, a model endocrine-disruption compound. This comparative study of BPA removal showed that among the approaches employed, the effectiveness of BPA degradation (10 mg/L) decreased in the order: Solar/PS/Fe2+> Solar/PS > PS/Fe2+> Solar/Fe2+> Solar. The complete degradation of BPA was achieved by Solar/PS/Fe2+ treatment at a [PS]:[BPA] ratio of 20 in less than t30W 5 in deionised water. The high efficiency of the Solar/PS/Fe2+ process revealed a synergistic effect (ϕ = 2.38) between the applied activation agents on the formation of reactive oxygen species (ROS) and subsequent decomposition of BPA. The treatment was accompanied by total organic carbon (TOC) removal (44%) in 45 min. Sequential generation of reactive oxygen species has made Solar/PS/Fe2+ a kinetically effective process for removing BPA without accumulation of toxic intermediates. The reaction rate followed pseudo-first-order kinetics that increased with increasing PS and Fe2+ concentrations. Experimental evidence suggests that exposure to solar irradiation maintains suitable quantities of free Fe2+ in the reaction mixture, even at low catalyst concentrations (the molar ratio of [PS]:[Fe2+] varied from 1:0.01 to 1:0.08). The effects of HCO3-, SO42-, and Cl- were also examined. As expected, HCO3- and SO42- inhibited BPA oxidation. The effect of Cl- on the oxidation efficiency of BPA in Fenton-like systems depends not only on actual Cl- concentrations but it is also highly influenced by molar ratios of Cl- to oxidant and catalyst. Inhibition, which was caused by Cl- in the mM range can be overcome by prolonging the reaction time or increasing the initial Fe2+concentration. Finally, the efficiency of Solar/PS/Fe2+ process was examined in diluted natural surface water and wastewater effluent. On eliminating the buffering action of HCO3-/CO32- ions by lowering the pH value to 4.5, complete BPA degradation was achieved in all real water matrices.


Assuntos
Compostos Benzidrílicos , Poluentes Químicos da Água , Peróxido de Hidrogênio , Oxirredução , Fenóis , Luz Solar , Águas Residuárias
9.
Environ Monit Assess ; 191(9): 568, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31418094

RESUMO

Accurate estimates of total global solar irradiance reaching the Earth's surface are relevant since routine measurements are not always available. This work aimed to determine which of the models used to estimate daily total global solar irradiance (TGSI) is the best model when irradiance measurements are scarce in a given site. A model based on an artificial neural network (ANN) and empirical models based on temperature and sunshine measurements were analyzed and evaluated in Córdoba, Argentina. The performance of the models was benchmarked using different statistical estimators such as the mean bias error (MBE), the mean absolute bias error (MABE), the correlation coefficient (r), the Nash-Sutcliffe equation (NSE), and the statistics t test (t value). The results showed that when enough measurements were available, both the ANN and the empirical models accurately predicted TGSI (with MBE and MABE ≤ |0.11| and ≤ |1.98| kWh m-2 day-1, respectively; NSE ≥ 0.83; r ≥ 0.95; and |t values| < t critical value). However, when few TGSI measurements were available (2, 3, 5, 7, or 10 days per month) only the ANN-based method was accurate (|t value| < t critical value), yielding precise results although only 2 measurements per month were available for 1 year. This model has an important advantage over the empirical models and is very relevant to Argentina due to the scarcity of TGSI measurements.


Assuntos
Monitoramento Ambiental/métodos , Modelos Teóricos , Luz Solar , Argentina , Monitoramento Ambiental/estatística & dados numéricos , Redes Neurais (Computação) , Análise de Regressão , Temperatura Ambiente
10.
An Bras Dermatol ; 94(3): 279-286, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365655

RESUMO

BACKGROUND: Exposure to UVR provides benefits related to vitamin D synthesis, but also causes harms, since UVB is considered a complete carcinogen. There is no definition of the level of sun exposure and the proportion of exposed body required for proper synthesis of vitamin D in the skin without causing it damage. OBJECTIVES: This study aims to analyze the sun exposure index, vitamin D levels and clinical changes in the skin caused by constant sun exposure in the fishermen population. METHODS: It is a cross-sectional, observational and analytical study. The sample consisted of fishermen and was calculated in 174 individuals. The questionnaire was applied, the dermatological examination was carried out and the examinations of calcidiol, parathyroid hormone, calcium and phosphorus were requested. Data were expressed as percentages. The comparative analysis was done through the Chi-square test, and the correlations were established through the Pearson's linear coefficient. Results: We observed that there was vitamin D deficiency in a small part of the cases (11.46%), and the frequency of diagnosis of skin cancer was 2.7% of the cases surveyed. STUDY LIMITATIONS: The difficulty in categorizing the sun exposure index. CONCLUSION: The fact that fishermen expose themselves to the sun chronically and have been exposed to the sun for more than 15 years, between 21 and 28 hours a week, and without photoprotection, were indicative factors for protection against vitamin D deficiency. Chronic exposure to sun and high vitamin levels D may be indicative of protection of this population against skin cancer.


Assuntos
Neoplasias Cutâneas/epidemiologia , Neoplasias Cutâneas/etiologia , Luz Solar , Raios Ultravioleta , Deficiência de Vitamina D/epidemiologia , Deficiência de Vitamina D/reabilitação , Vitamina D/biossíntese , Adulto , Índice de Massa Corporal , Brasil/epidemiologia , Estudos Transversais , Dieta , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estado Nutricional , Inquéritos e Questionários , Vitamina D/sangue
11.
An Bras Dermatol ; 94(3): 331-333, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365663

RESUMO

Solar urticaria is a rare form of physical urticaria mediated by immunoglobulin E. The lesions appear immediately after the sun exposure, interfering with the patient's normal daily life. Omalizumab, a monoclonal anti-IgE antibody, has been recently approved for the treatment of chronic spontaneous urticaria, and the latest reports support its role also in the treatment of solar urticaria. Hereby, we report a case of solar urticaria refractory to conventional treatment strategies, with an excellent response to treatment with omalizumab and phototesting normalization.


Assuntos
Antialérgicos/uso terapêutico , Omalizumab/uso terapêutico , Luz Solar/efeitos adversos , Urticária/tratamento farmacológico , Humanos , Masculino , Pessoa de Meia-Idade , Transtornos de Fotossensibilidade/diagnóstico , Transtornos de Fotossensibilidade/tratamento farmacológico , Transtornos de Fotossensibilidade/etiologia , Urticária/diagnóstico , Urticária/etiologia
12.
Zhongguo Zhong Yao Za Zhi ; 44(13): 2753-2761, 2019 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-31359687

RESUMO

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var. mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors. It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage. At expanding leaf stage,the rate of Chla and Chlb was 3. 11 when A. heterotropoides var. mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3. 0 when they grew in shading environment. The content of Chla,Chlb and Chl( a+b) was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably( P<0. 05). The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl( a+b) increased gradually with continued shading. The maximum value of photosynthetically active radiation appeared at 10: 00-12: 00 am in a day. The maximum value of net photosynthetic rate appeared at 8: 30-9: 00 am and the minimum value appeared at 14: 00-14: 30 pm at each phenological stage if plants grew in full sunlight. However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10: 30 am and the minimum value appeared at 12: 20-12: 50 pm at each phenological stage. At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually( P < 0. 05). However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50% and 28% full sunlight but higher than those in 12% full sunlight. All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis. The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12% full sunlight. Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12% full sunlight. Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments. Only,in 12% full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity. In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance. Volatile oil content was 1. 46%,2. 16%,1. 56%,1. 30% respectively. ethanol extracts was 23. 44%,22. 45%,22. 18%,21. 12% respectively. Asarinin content was 0. 281%,0. 291%,0. 279% and 0. 252% respectively. The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.


Assuntos
Asarum/fisiologia , Asarum/efeitos da radiação , Fotossíntese , Luz Solar , Clorofila/análise , Folhas de Planta/efeitos da radiação
13.
Bioresour Technol ; 291: 121801, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31326685

RESUMO

Achieving high biomass productivity is critical for establishing a successful large-scale algal facility. Microalgae cultures in raceway ponds are normally light limited. To achieve high biomass productivity, there is a need to develop a system to deliver light into the depth of microalgal cultures in raceway ponds. We investigated red and blue luminescent solar concentrators (LSCs) in outdoor raceway ponds to downgrade the sunlight, re-emit and, deliver it into the depth of Arthrospira platensis culture operated at 21 cm depth. When red LSCs were used, the biomass productivity (12.2 g m-2 d-1) and phycocyanin productivity (8.5 mg L-1 d-1) of A. platensis increased 26% and 44%, respectively. However, using blue LSCs resulted in no significant increase in A. platensis biomass productivity. Therefore, for generating same phycocyanin productivity using red LSCs, 44% less cultivation area would be required. This can lead to a significant reduction in the cost of phycocyanin production.


Assuntos
Biomassa , Ficocianina/biossíntese , Tanques/microbiologia , Spirulina/metabolismo , Cor , Luminescência , Microalgas/metabolismo , Luz Solar
14.
J Photochem Photobiol B ; 197: 111545, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31326847

RESUMO

Proper waste utilization in order to promote value added product is a promising scientific practice in recent era. Inspiring from the recurring trend, we propose a single step oxidative pyrolysis derived fluorescent carbon dots (C-dots) from Allium sativum peel, which is a natural, nontoxic, and waste raw material. Because of its excellent optical properties, and photostability this C-dots have been used in versatile area of applications. Due to its immediate water dispersing character, C-dots reinforced Poly(acrylic acid) (PAA) films revealed improvement in uniaxial stretching behavior and can be used as transparent sunlight conversion film. The nanocomposite film has been tested against rigorous simulated sunlight which proved almost identical sunlight conversion behavior with no photo-bleachable character which is definitely added an extra quality of transparent polymer films. Moreover, the C-dots dispersion has been used as in vitro biomarker for living cells owing to its ease in solubility, biocompatibility, non-cytotoxicity and bright fluorescence even in subcutaneous environment. For this case, adipose derived mesenchymal stem cells (ADMSCs) have been chosen and injected to rabbit ear skin to perform two-photon imaging experiment. The present work opens a new avenue towards the large-scale synthesis of bio-waste based fluorescent C-dots, paving the way for their versatile applications.


Assuntos
Allium/química , Nitrogênio/química , Fotodegradação/efeitos da radiação , Pontos Quânticos/química , Enxofre/química , Luz Solar , Resinas Acrílicas/química , Tecido Adiposo/citologia , Allium/metabolismo , Animais , Materiais Biocompatíveis/química , Carbono/química , Sobrevivência Celular/efeitos dos fármacos , Frutas/química , Frutas/metabolismo , Química Verde , Masculino , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Microscopia de Fluorescência , Pontos Quânticos/toxicidade , Coelhos , Pele/efeitos dos fármacos , Pele/patologia , Solubilidade
15.
Nature ; 571(7763): 38-39, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31270487
16.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2011-2020, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257774

RESUMO

The photosynthesis response of the leaves of 2-year-old potted Dendrocalamopsis oldhami seedlings under continuous and multistage soil moisture was measured and analyzed by using a porta-ble photosynthetic system (Li-6400) during the natural water consumption process from artificial watering to saturated soil water. The results showed that there was less obvious photoinhibition in leaves of D. oldhami grown in the region where the relative soil water content (SRWC) was from 53.5% to 95.6%. There was a higher net photosynthetic rate in relative water deficit environment with the relative soil water content from 53.5% to 69.6%. When SRWC was below 33.6%, there was a significant photoinhibition. When the relative soil water changed, the Pn max value simulated by rectangular hyperbola model was much higher than measured value. The simulated light saturation point (LSP) value fitted by the rectangular hyperbola model, the non-rectangular hyperbola model and the exponential model was much lower than the measured value, and the simulation of the light-response curve under extreme water shortage conditions had larger differences between the fitted values and the observed data. Both the stomatal limitation value (Ls) and water use efficiency (WUEinst) showed a similar response process as the relative soil water decreased. Both of them increased first and then decreased, with the maximum value appeared in the range of 53.5%≤SRWC≤69.6%. Such a result showed a similarity and representative with the Pn max of photosynthesis light-response processes under changing soil moisture. The optimal humidity management range of SRWC for normal photosynthesis in leaves of D. oldhami was from 53.5% to 69.6%. In addition, it had good adaptability to higher soil water content (69.6%≤SRWC≤95.6%). Rectangular hyperbola modified model could well simulate the light-response of photosynthesis under different soil water conditions (23.1%≤SRWC≤95.6%), while the other three models had their own limitations.


Assuntos
Bambusa/fisiologia , Luz Solar , Água , Fotossíntese , Folhas de Planta , Solo
17.
Ying Yong Sheng Tai Xue Bao ; 30(6): 2072-2078, 2019 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-31257781

RESUMO

An experiment with single-factor design was conducted to investigate the effects of light intensity on growth and survival of cuttlefish (Sepia pharaonis). The specific growth rate, survival rate, oxygen consumption rate, ammonia excretion rate, lactic acid content in muscle, respiratory metabolic enzymes (including hexokinase, pyruvate kinase, and lactate dehydrogenase), supero-xide dismutase, and malondialdehyde in liver were measured in five constant light intensity treatments (10, 30, 50, 70, 90 µmol·m-2·s-1). The main results were as follows: The specific growth rate and survival rate remained steady initially and then decreased gradually with the increases of light intensity. There was no significant difference between groups 10 and 30 µmol·m-2·s-1, but they were significantly higher than those of the other groups. Exposed to light intensities of 10 and 30 µmol·m-2·s-1, the specific growth rates were (8.43±0.22)%·d-1 and (8.47±0.17)%·d-1, and the survival rates were (79.2±5.9)% and (80.0±4.9)%, respectively. Oxygen consumption rates and ammonia excretion rates increased first slowly and then sharply, and reached the maximum value when light intensity was 90 µmol·m-2·s-1, which was significantly higher than those of the other groups. Lactic acid content in muscle firstly decreased and then increased, with the minimum value at 30 µmol·m-2·s-1. The acid content of 10 µmol·m-2·s-1 was significantly lower than those of the other groups except 30 and 50 µmol·m-2·s-1. With the increases of light intensity, the activities of HK and PK in gills remained steady initially and then decreased gradually, and reached the highest level when exposed to 10 and 30 µmol·m-2·s-1, which were significantly higher than those of the other groups. LDH activity in muscle had the lowest level at the light intensity of 10 and 30 µmol·m-2·s-1, which was significantly lower than those of the other groups. SOD activity in liver firstly increased and then decreased, and reached the highest level ((104.93±4.17) U·mg-1 pro) when exposed to 70 µmol·m-2·s-1, which was significantly higher than those of the other groups. MDA content in liver first remained steady and then increased gradually, and reached the highest level ((5.06±0.35) nmol·mg-1 pro) when exposed to 90 µmol·m-2·s-1, which was significantly higher than those of the other groups. In conclusion, the optimum light intensities for growth, survival and metabolism of S. pharaonis were 10 and 30 µmol·m-2·s-1, beyond which S. pharaonis would be under stress. Therefore, sunproof measures should be taken to keep weak light condition in culture practice.


Assuntos
Sepia/fisiologia , Luz Solar , Animais , Fígado , Malondialdeído , Músculos , Sepia/enzimologia
18.
Waste Manag ; 94: 18-26, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31279392

RESUMO

Leachate organic matter (LOM) from mature, stabilized landfills is recalcitrant in nature resulting from high concentrations of humic substances, such as humic acids and other complex organic matter. This research focused on the behavior and fate of LOM in aquatic sun-lit systems to address the extent and mechanisms of LOM photodegradation by exposing leachate to natural sunlight in central Florida for a period of 90 days. Transformation processes were measured using ultraviolet-visible (UV-Vis) spectroscopy, fluorescence excitation-emission matrix spectroscopy, size-exclusion chromatography, and chemical oxygen demand over the test period. Results of the study suggest that photolytic, and in some cases biological, reactions were responsible for the reduction of LOM demonstrated by the transformation of high molecular weight recalcitrant material to lower molecular weight material, loss of fluorescence and color, and reduction of UV254 absorbance.


Assuntos
Luz Solar , Poluentes Químicos da Água , Florida , Substâncias Húmicas , Instalações de Eliminação de Resíduos
19.
J Agric Food Chem ; 67(27): 7609-7615, 2019 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-31257874

RESUMO

Shallow water systems are uniquely susceptible to environmental processes such as photolysis and hydrolysis that can influence the dissipation of pesticides into sediments. The fungicide dicloran has previously been shown to undergo photolysis and is reported to dissipate in soils and sediments. The photodegradation and dissipation of dicloran in freshwater and seawater was monitored in a laboratory-simulated shallow water system. While no difference was observed between freshwater and seawater systems in the presence of simulated sunlight, the dissipation of dicloran in dark trial systems differed between salinities; 30% of the applied mass dissipated into the sediment in freshwater vs 22% in seawater, and the photodegradation rate and half-life were also impacted by the presence of sediment. The potential for dicloran to dissipate and photodegrade affects the overall behavior of dicloran between waters. Differences in chemical behavior with sediment presence and potential for photodegradation have the capacity to impact organisms within the ecosystem and suggest that these factors may need to be implemented into chemical exposure assessments dependent upon location.


Assuntos
Compostos de Anilina/química , Água Doce/química , Sedimentos Geológicos/química , Fotólise , Água do Mar/química , Luz Solar , Ecossistema , Fungicidas Industriais/química , Solo/química , Poluentes Químicos da Água/química
20.
Environ Sci Pollut Res Int ; 26(24): 25359-25371, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31256408

RESUMO

In the present article, Fe3O4@TiO2 core/shell (FT) linked to graphene was fabricated by sol-gel technique as a photocatalyst and was employed for the solar degradation of cationic methylene blue (MB) in aqueous solution. The prepared core/shells were linked to graphene oxide (FTGO) and reduced graphene oxide (FTRGO) via embedding into 3-aminopropyltrimethoxysilane (APS). The structure of this magnetic composition was characterized by X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometry (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and BET surface area measurements. The significance of the composite structure in photocatalytic degradation was spectrophotometrically tested by blending the obtained powders with wastewater containing methylene blue under solar irradiation. The appropriate dosage of APS to link the Fe3O4@TiO2 core/shell onto GO and RGO surfaces was determined to be 1 ml per gram of FT. The kinetic studies were performed to investigate the effects of different parameters, such as composition structure, APS dosage, and repeatability. Kinetic data are well fitted by a first-order model with a high correlation coefficient. Regardless of the prominent advantage of composites in magnetic powder separation, the Fe3O4@TiO2 core/shell linked to graphene oxide is an efficient composite in comparison to FTRGO for the dye degradation without losing the original activity and stability.


Assuntos
Grafite/química , Azul de Metileno/química , Processos Fotoquímicos , Silanos/química , Catálise , Cinética , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Compostos Orgânicos , Óxidos/química , Luz Solar , Difração de Raios X
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