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1.
Foods ; 13(16)2024 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-39200534

RESUMEN

In this study, indigo carmine (IC)-calcium carbonate lakes with different crystalline forms of calcium carbonate were prepared through co-precipitation methods, and the properties of these lakes and their formation mechanisms were investigated. The results showed that amorphous calcium carbonate (ACC) exhibited the smallest particle size and the largest specific surface area, resulting in the highest adsorption efficiency. Vaterite, calcite, and aragonite followed after ACC in decreasing order of adsorption efficiency. Kinetic analysis and isothermal analysis revealed the occurrence of chemisorption and multilayer adsorption during formation of the lakes. The FTIR and Raman spectra suggested participation of sulfonic acid groups in chemisorption. Appearance of IC significantly altered TGA curves by changing weight loss rate before decomposition of calcium carbonate. EDS analysis revealed the adsorption of IC predominantly happened on the surface of calcium carbonate particles rather than the interior.

2.
World J Clin Cases ; 12(20): 4384-4390, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39015899

RESUMEN

BACKGROUND: Enterocutaneous fistula (ECF) is an abnormal connection between the gastrointestinal tract and the skin. ECF can lead to massive body fluid loss, hypercatabolism, and malnutrition. Therefore, nutritional support plays a crucial role in managing ECFs and promoting the healing of fistulas. For nutritional support, enteral nutrition (EN) is the preferred method when gastrointestinal function is recovering. Currently, various EN approaches have been applied for different anatomical positions of the ECF. However, the effectiveness of administering EN support for treating lower ECFs still needs further exploration and improvement. CASE SUMMARY: We present the case of a 46-year-old male who underwent gastrointestinal stromal tumour resection. Six days after the surgery, the patient presented with fever, fatigue, severe upper abdominal pain, and septic shock. Subsequently, lower ECFs were diagnosed through laboratory and imaging examinations. In addition to symptomatic treatment for homeostasis, total parenteral nutrition support was administered in the first 72 h due to dysfunction of the intestine. After that, we gradually provided EN support through the intestinal obstruction catheter in consideration of the specific anatomic position of the fistula instead of using the nasal jejunal tube. Ultimately, the patient could receive optimal EN support via the catheter, and no complications were found during the treatment. CONCLUSION: Nutritional support is a crucial element in ECF management, and intestinal obstruction catheters could be used for early EN administration.

3.
Environ Sci Technol ; 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39016874

RESUMEN

Emerging aryl organophosphate esters (aryl-OPEs) have been employed as substitutes for organohalogen flame retardants in recent years; however, their environmental occurrence and associated impacts in urban estuarine sediments have not been adequately investigated, impeding regulatory decision-making. Herein, field-based investigations and modeling based on surface sediment and sediment core analysis were employed to uncover the historical pollution and current environmental impacts of aryl-OPEs in the Pearl River Estuary, South China. Our results revealed a substantial increase in aryl-OPE emission, particularly emerging aryl-OPEs, through sediment transport to the estuary since the 2000s. The emerging aryl-OPEs comprised 83% of the total annual input in the past decade, with an average annual input of 155,000 g. Additionally, the emerging-to-traditional aryl-OPE concentration ratios increased with decreasing distance from the shore, peaking in the highly urbanized riverine outlets. These findings indicate that inventories of emerging aryl-OPEs are likely increasing in estuarine sediments and their emissions are surpassing those of traditional aryl-OPEs. Our risk-based priority screening approach indicates that some emerging aryl-OPEs, particularly bisphenol A bis(diphenyl phosphate), can pose a higher environmental risk than traditional aryl-OPEs in estuarine sediments. Overall, our study highlights the importance of recognizing the environmental impacts of emerging aryl-OPEs.

4.
Foods ; 13(7)2024 Mar 29.
Artículo en Inglés | MEDLINE | ID: mdl-38611355

RESUMEN

This study prepared a novel ß-carotene colorant lake using calcium carbonate (CaCO3) and investigated the lake formation process and its basic characteristics. Kinetic adsorption analysis confirmed that medium pH (9.3) and medium temperature (40 °C) were more suitable for lake preparation, while desorption occurred, possibly due to crystalline transformation of CaCO3. The isothermal analysis and model fitting results suggested that the ß-carotene and CaCO3 particles combined via a monolayer adsorption process driven by physical force. Electrostatic attraction likely participated in the process due to the net negative surface charges of ß-carotene dispersion and positively charged groups on the CaCO3 particle surfaces. Ethanol, ultrasonic treatment, and drying method significantly influenced the immobilization efficiency (IE) of ß-carotene in the lake and light stability of the lake, without affecting its crystal form. The thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) curves confirmed absorption of ß-carotene onto CaCO3. Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses indicated no obvious chemical bonds between ß-carotene and CaCO3. Energy-dispersive spectroscopy (EDS) confirmed the presence of ß-carotene on surfaces but not in the interior of the CaCO3 particles. The adsorption of ß-carotene by calcium carbonate was further confirmed to be a physical adsorption on surface.

5.
Clin Pediatr (Phila) ; : 99228241245343, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38606919

RESUMEN

This research aimed to investigate the diagnostic value of passive particle agglutination test, Mycoplasma pneumoniae (MP) culture, cold agglutination test (CAT), enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction-capillary electrophoresis fragment analysis (PCR-CEFA) for MP infection. Children with respiratory tract infections suspected to be MP infection were subjected to passive particle agglutination test, MP culture, CAT, ELISA, and PCR-CEFA. A total of 146 children (81 males, 65 females, mean age: 5.74 ± 3.32 years, and mean course of disease: 9.07 ± 5.18 days) met the inclusion criteria. The positivity rate of MP detection by MP culture was 69.18% (101/146). Using the MP culture method as the standard, higher sensitivity and positive predictive value were found in the PCR-CEFA compared with the other 3 methods. Appropriate methods are selected following the advantages and disadvantages of pathogen detection, and pediatric MP infection is analyzed by integrating various test results.

6.
Int J Biol Macromol ; 269(Pt 2): 131894, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38677674

RESUMEN

N-methyl-morpholine-N-oxide (NMMO) was initially created as a plasticizer for starch to produce thermoplastic wheat starch. Subsequently, talc powder was used as a reinforcing filler to enhance the mechanical strength of thermoplastic biomass-based composite plastics. The chemical structure, crystal structure, and microscopic morphology were analyzed using Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Additionally, the thermal properties were explored through thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. The hydrated NMMO plasticizer demonstrated an outstanding plasticizing effect on starch, resulting in a composite with remarkable mechanical properties. In fact, the pure thermoplastic wheat starch plasticized with hydrated NMMO exhibited the highest mechanical strength recorded so far, with a tensile strength of up to 9.4 MPa. In addition, talcum powder displayed a noticeable reinforcing effect. When the talcum powder content reached 30 wt%, the targeted composite achieved a tensile strength of 20.5 MPa and a Young's modulus of 177.9 MPa. These values were 118 % and 48 % higher, respectively, than those of the pure thermoplastic starch sample. This innovative plasticizing method opens up a new avenue for the development of high-mechanical-strength thermoplastic biomass-based composite plastics with promising potential applications.


Asunto(s)
Biomasa , Plastificantes , Plásticos , Almidón , Talco , Resistencia a la Tracción , Triticum , Almidón/química , Talco/química , Triticum/química , Plásticos/química , Plastificantes/química , Polvos , Espectroscopía Infrarroja por Transformada de Fourier , Termogravimetría , Fenómenos Mecánicos , Difracción de Rayos X
7.
Biomed Environ Sci ; 36(8): 743-755, 2023 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-37711086

RESUMEN

This review aims to sum up how Non-coding RNAs (ncRNAs) regulate the development of periodontitis and provides a new perspective for understanding the pathogenesis of periodontitis. We explored the ncRNA's dual role in the development of periodontitis by summarizing evidence from previous in vivo and in vitro studies as well as clinical samples. In our review, the downregulation of 18 miRNAs, 22 lncRNAs and 10 circRNAs demonstrates protective roles in periodontitis. In contrast, the expression of other 11 miRNAs, 7 lncRNAs and 6 circRNAs are upregulated in periodontitis, which promote the progression of periodontitis. These dysregulated ncRNAs exert their protective or destructive roles by mainly influencing cell proliferation, differentiation and apoptosis via cross-talking with various molecules or signaling pathways. Our findings suggested which and how ncRNAs promote or delay the progression of periodontitis, which may greatly contribute to diagnose and therapy development of periodontitis based on ncRNAs in the future.


Asunto(s)
MicroARNs , Periodontitis , ARN Largo no Codificante , Humanos , ARN Largo no Codificante/genética , ARN Circular , Periodontitis/genética , Apoptosis
8.
Food Chem ; 410: 135408, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-36640653

RESUMEN

Monascus pigments (MPs) were adsorbed using calcium carbonate to produce CaCO3-MPs lakes. The fundamental properties and formation mechanism of the lakes were investigated. Results indicated that CaCO3 displayed a high enough affinity for the MPs to form colorant lakes, while the MPs tended to transform the CaCO3 crystals from calcite to vaterite. The adsorption of MPs by CaCO3 followed the Freundlich isothermal model with n value higher than 1, confirming it as physical adsorption. The ΔG0 (-29 to ∼-33 kJ/mol) and ΔH0(30-55 kJ/mol) indicated that lake formation was a spontaneous and endothermic process. UV/Vis spectroscopic analysis verified the complex formation between Ca2+ and MPs via physical bonding, suggesting a possible attraction between the Ca2+ and glutamate residues of the MPs. EDS showed that the MPs were trapped inside the particles. FTIR spectroscopy and XPS further confirmed that the physical bonding was the primary driving force behind the lake formation.


Asunto(s)
Monascus , Lagos , Carbonato de Calcio/química , Espectroscopía Infrarroja por Transformada de Fourier
9.
Artículo en Inglés | WPRIM (Pacífico Occidental) | ID: wpr-1007847

RESUMEN

This review aims to sum up how Non-coding RNAs (ncRNAs) regulate the development of periodontitis and provides a new perspective for understanding the pathogenesis of periodontitis. We explored the ncRNA's dual role in the development of periodontitis by summarizing evidence from previous in vivo and in vitro studies as well as clinical samples. In our review, the downregulation of 18 miRNAs, 22 lncRNAs and 10 circRNAs demonstrates protective roles in periodontitis. In contrast, the expression of other 11 miRNAs, 7 lncRNAs and 6 circRNAs are upregulated in periodontitis, which promote the progression of periodontitis. These dysregulated ncRNAs exert their protective or destructive roles by mainly influencing cell proliferation, differentiation and apoptosis via cross-talking with various molecules or signaling pathways. Our findings suggested which and how ncRNAs promote or delay the progression of periodontitis, which may greatly contribute to diagnose and therapy development of periodontitis based on ncRNAs in the future.


Asunto(s)
Humanos , ARN Largo no Codificante/genética , ARN Circular , MicroARNs , Periodontitis/genética , Apoptosis
10.
Artículo en Chino | WPRIM (Pacífico Occidental) | ID: wpr-1008858

RESUMEN

Hypertension, a primary cause of cardiovascular and cerebrovascular events, has become a major global public health problem and caused a heavy burden of health economics on the society. In "the 20 Most Important and Most Preventable Health Problems" released by the Chinese Academy of Engineering, hypertension was ranked the second. Due to the disease complexity, many hypertension patients need to take antihypertensive drugs for life. Although significant progress has been achieved in blood pressure lowering by western medicines, the problems including adverse reactions, poor compliance due to long-term medication, and ineffective mitigation in clinical symptoms related to hypertension remain to be addressed. In the last decade, the research on traditional Chinese medicine(TCM) treatment of hypertension has received much attention and achieved remarkable progress. The TCM treatment of hypertension is the most active area of research with integrated Chinese and western medicine in China. In addition to lowering blood pressure smoothly, TCM can alleviate clinical symptoms, reverse risk factors, improve the quality of life, and protect target organs from the damage caused by hypertension. This article systematically reviews the research progress of TCM in treating hypertension in the last decade from the following four aspects: consensus on guideline, clinical trial, experimental study, and systematic review/Meta-analysis. It summarized the evidence of TCM in reducing blood pressure and clarified the mechanism of TCM in reducing blood pressure, aiming to provide a reference for the TCM diagnosis and treatment of hypertension and the development of new drugs.


Asunto(s)
Humanos , Antihipertensivos/uso terapéutico , Medicamentos Herbarios Chinos/uso terapéutico , Hipertensión/tratamiento farmacológico , Medicina Tradicional China
11.
Zhongguo Zhong Yao Za Zhi ; 48(24): 6592-6599, 2023 Dec.
Artículo en Chino | MEDLINE | ID: mdl-38212019

RESUMEN

Hypertension, a primary cause of cardiovascular and cerebrovascular events, has become a major global public health problem and caused a heavy burden of health economics on the society. In "the 20 Most Important and Most Preventable Health Problems" released by the Chinese Academy of Engineering, hypertension was ranked the second. Due to the disease complexity, many hypertension patients need to take antihypertensive drugs for life. Although significant progress has been achieved in blood pressure lowering by western medicines, the problems including adverse reactions, poor compliance due to long-term medication, and ineffective mitigation in clinical symptoms related to hypertension remain to be addressed. In the last decade, the research on traditional Chinese medicine(TCM) treatment of hypertension has received much attention and achieved remarkable progress. The TCM treatment of hypertension is the most active area of research with integrated Chinese and western medicine in China. In addition to lowering blood pressure smoothly, TCM can alleviate clinical symptoms, reverse risk factors, improve the quality of life, and protect target organs from the damage caused by hypertension. This article systematically reviews the research progress of TCM in treating hypertension in the last decade from the following four aspects: consensus on guideline, clinical trial, experimental study, and systematic review/Meta-analysis. It summarized the evidence of TCM in reducing blood pressure and clarified the mechanism of TCM in reducing blood pressure, aiming to provide a reference for the TCM diagnosis and treatment of hypertension and the development of new drugs.


Asunto(s)
Medicamentos Herbarios Chinos , Hipertensión , Humanos , Antihipertensivos/uso terapéutico , Medicamentos Herbarios Chinos/uso terapéutico , Hipertensión/tratamiento farmacológico , Medicina Tradicional China
12.
Huan Jing Ke Xue ; 43(8): 3903-3912, 2022 Aug 08.
Artículo en Chino | MEDLINE | ID: mdl-35971689

RESUMEN

The aerosol size distribution is an important physical parameter reflecting the source, formation process, and pollution characteristics of aerosol particles. In order to study the properties of aerosol number concentration and size distributions in the Tianjin urban area,the aerosol number concentration and size distributions ranging from 10-600 nm were detected using a scanning mobility particle sizer (SMPS) during February and March, 2019. The results showed that in the Tianjin urban area, the aerosol number concentration,surface area concentration. and volume concentration in the size range of 10-600 nm were 22188.22 cm-3, 1581.08 µm2·cm-3, and 70.76 µm3·cm-3,respectively, in late winter and early spring. The aerosol number concentration,surface area concentration, and volume concentration spectrum were all unimodally distributed,and the peak value sizes were 109.40, 269.00, and 429.40 nm. The number concentrations of the nucleation mode (10-20 nm),Aitken mode (20-100 nm), and accumulation mode (100-600 nm) aerosols accounted for 1.40%, 52.44%, and 46.16% of the total number concentration. The diurnal variation in aerosol number concentration showed three peaks (06:00-08:00, 12:00-14:00, and 18:00-20:00) on work days and two peaks (07:00-08:00 and 19:00-21:00) on weekends. The peaks appeared 1-2 hours later on weekends,and the increment of aerosol number concentration was attributed to vehicle exhaust emissions. Meteorological factors had a significant influence on the aerosol size distribution in Tianjin; aerosol number concentration values were high in east and southwest wind. On non-precipitation days,the aerosol number size distribution moved to larger size ranges with the increment of relative humidity (RH); as the RH increased from <20% to 50%-60%,the size peak increased from 50 nm to 131 nm. The precipitation removed 100-200 nm aerosol particles discernibly,which resulted in the size peak decreasing to 98 nm.


Asunto(s)
Contaminantes Atmosféricos , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente/métodos , Tamaño de la Partícula , Material Particulado/análisis , Emisiones de Vehículos/análisis
13.
Chem Sci ; 13(30): 8813-8820, 2022 Aug 04.
Artículo en Inglés | MEDLINE | ID: mdl-35975161

RESUMEN

The development of biosensors capable of achieving accurate and precise molecular measurements in the living body in pH-variable biological environments (e.g. subcellular organelles, biological fluids and organs) plays a significant role in personalized medicine. Because they recapitulate the conformation-linked signaling mechanisms, electrochemical aptamer-based (E-AB) sensors are good candidates to fill this role. However, this class of sensors suffers from a lack of a stable and pH-independent redox reporter to support their utility under pH-variable conditions. Here, in response, we demonstrate the efficiency of an electron donor π-extended tetrathiafulvalene (exTTF) as an excellent candidate (due to its good electrochemical stability and no proton participation in its redox reaction) of pH-independent redox reporters. Its use has allowed improvement of E-AB sensing performance in biological fluids under different pH conditions, achieving high-frequency, real-time molecular measurements in biological samples both in vitro and in the bladders of living rats.

15.
Plants (Basel) ; 10(12)2021 Nov 25.
Artículo en Inglés | MEDLINE | ID: mdl-34961051

RESUMEN

Our study, which was conducted in the desert grassland of Ningxia in China (E 107.285, N 37.763), involved an experiment with five levels of annual precipitation 33% (R33), 66% (R66), 100% (CK), 133% (R133), 166% (R166) and two temperature levels (inside Open-Top Chamber (OTC) and outside OTC). Our objective was to determine how plant, soil bacteria, and fungi diversity respond to climate change. Our study suggested that plant α-diversity in CK and TCK were significantly higher than that of other treatments. Increased precipitation promoted root biomass (RB) growth more than aboveground living biomass (ALB). R166 promoted the biomass of Agropyron mongolicum the most. In the fungi communities, temperature and precipitation interaction promoted α-diversity. In the fungi communities, the combination of increased temperature and natural precipitation (TCK) promoted ß-diversity the most, whose distance was determined to be 25,124 according to PCA. In the bacteria communities, ß-diversity in CK was significantly higher than in other treatments, and the distance was determined to be 3010 according to PCA. Soil bacteria and fungi α- and ß-diversity, and ALB promoted plant diversity the most. The interactive effects of temperature and precipitation on C, N, and P contents of plants were larger than their independent effects.

16.
Huan Jing Ke Xue ; 42(11): 5210-5219, 2021 Nov 08.
Artículo en Chino | MEDLINE | ID: mdl-34708960

RESUMEN

Real-time BTEX(including benzene, toluene, ethylbenzene, m-, p-, and o-xylenes) were measured continuously in Tianjin urban site in July 2019 and January 2020 using a Syntech Spectras GC955 analyzer. The BTEX concentration levels, composition, and evolutionary mechanisms during typical pollution episodes were investigated. The potential sources of BTEX were analyzed qualitatively using the diagnostic ratios method. Finally, the BTEX health risk was evaluated by using the human exposure analysis and evaluation method according to US EPA. The averaged total mixing ratio of BTEX were 1.32×10-9 and 4.83×10-9 during ozone pollution and haze episodes, respectively. Benzene was the most abundant species, followed by toluene. The mixing ratio of BTEX was largely affected by short southwestern distance transportation in January, while local emissions in July. In addition, the BTEX mixing ratio depended on the influence of temperature and relative humidity(RH) in July, while the concentration was more sensitive to changes in RH when the temperature was low in January. Diagnostic ratios and source implications suggested that the BTEX was affected mainly by biomass/biofuel/coal burning during haze episodes. The traffic related emissions also had an impact except for the influence of biomass/biofuel/coal burning in July. The averaged hazard quotient(HQ) values were 0.072 and 0.29 during ozone pollution and haze episodes, respectively, which were in the upper safety range limit recommended by the US EPA. The carcinogenic risk posed by benzene in both cleaning and pollution processes was higher than the safety threshold set by the US EPA, which should be monitored carefully.


Asunto(s)
Contaminantes Atmosféricos , Contaminantes Atmosféricos/análisis , Contaminantes Atmosféricos/toxicidad , Benceno/análisis , Benceno/toxicidad , Derivados del Benceno/análisis , Derivados del Benceno/toxicidad , Monitoreo del Ambiente , Humanos , Medición de Riesgo , Tolueno/análisis , Tolueno/toxicidad , Xilenos
17.
World J Clin Cases ; 9(14): 3432-3441, 2021 May 16.
Artículo en Inglés | MEDLINE | ID: mdl-34002155

RESUMEN

BACKGROUND: Ectopic thyroid is defined as a rare developmental anomaly where thyroid tissues are atypically found in locations other than its normal anatomical position: Anterolateral to the second, third, and fourth tracheal cartilages. An intemperate descent or a migration failure of the thyroid anlage results in sub-diaphragmatic thyroid ectopia, a sparse clinical entity. CASE SUMMARY: This case portrays a 63-year-old female patient presenting with chronic abdominal discomfort at a local hospital whereby a computed tomography (CT) scan revealed a well-defined mass in the hepatic entrance. For further examination, the patient underwent a CT scan with contrast, magnetic resonance imaging (MRI), and CT-angiography (CTA) at our department. The CT scan showed a well-defined and high attenuated mass measuring 43 mm × 38 mm in the hepatic entrance with calcification. The CTA revealed an additional finding: Blood supply to the mass from the right hepatic artery. MRI of the upper abdomen demonstrated a mass with mixed signal intensity on T1 and T2 weighted images in the hepatic entrance. The patient underwent surgery with resection of the mass which was sent for histopathology. Ectopic thyroid at the level of porta hepatis with nodules was the definitive diagnosis since histopathological report revealed presence of thyroid tissue in the resected liver mass. CONCLUSION: This case delivers a rare insight of pre-operative radiological imaging of an ectopic thyroid located in the liver. These findings can aid in narrowing down potential differential diagnosis when managing a patient with those subsequent findings.

18.
PeerJ ; 9: e10729, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33604176

RESUMEN

BACKGROUND: Precipitation influences the vulnerability of grassland ecosystems, especially upland grasslands, and soil respiration is critical for carbon cycling in arid grassland ecosystems which typically experience more droughty conditions. METHODS: We used three precipitation treatments to understand the effect of precipitation on soil respiration of a typical arid steppe in the Loess Plateau in north-western China. Precipitation was captured and relocated to simulate precipitation rates of 50%, 100%, and 150% of ambient precipitation. RESULTS AND DISCUSSION: Soil moisture was influenced by all precipitation treatments. Shoot biomass was greater, though non-significantly, as precipitation increased. However, both increase and decrease of precipitation significantly reduced root biomass. There was a positive linear relationship between soil moisture and soil respiration in the study area during the summer (July and August), when most precipitation fell. Soil moisture, soil root biomass, pH, and fungal diversity were predictors of soil respiration based on partial least squares regression, and soil moisture was the best of these. CONCLUSION: Our study highlights the importance of increased precipitation on soil respiration in drylands. Precipitation changes can cause significant alterations in soil properties, microbial fungi, and root biomass, and any surplus or transpired moisture is fed back into the climate, thereby affecting the rate of soil respiration in the future.

19.
PeerJ ; 8: e8986, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32411518

RESUMEN

BACKGROUND: Our study evaluated how soil organic carbon (SOC) and soil inorganic carbon (SIC) recovered over time in deep loessial soil as overgrazed grassland was fenced and restored. METHODS: The study was conducted in the Yunwu Mountain Nature Reserve in the Ningxia Autonomous Region of China. In it we compared soil data from three grazed grassland (G) sites, three sites that were fenced for 15 years (F15), and three sites that were fenced for 30 years (F30) as a so-called 'space for time series'. RESULTS AND DISCUSSION: We compared SOC accumulation in soil up to 200 cm below the surface in G, F15, and F30 plots. An increase in SOC correlated with a decrease in soil pH, and decreased soil bulk density. However, SOC sequestration in fenced plots was largely offset by a decrease in SIC, which was closely correlated (r = 0.713, p = 0.001) with SOC-driven soil pH decline. We observed no significant increase in soil total carbon in the F15 or F30 sites after comparing them to G. CONCLUSIONS: Our data indicate that fencing causes the slow diffusion processes to intensify the soil property changes from increased litter return, and this slow diffusion process is still active 30 years after fencing at 100-200 cm soil depths in the studied deep loessial soil. These findings are likely applicable to similar sites.

20.
Huan Jing Ke Xue ; 40(1): 67-75, 2019 Jan 08.
Artículo en Chino | MEDLINE | ID: mdl-30628260

RESUMEN

The volume concentration of peroxyacetyl nitrate (PAN) and O3 in the atmosphere were measured at the Tianjin Meteorological Tower in summer 2017 by using the online instrument with meteorological parameters and back trajectory analysis to analyze the delivery characteristics of PAN and O3. The average volume concentrations of PAN and O3 during the observational period are (0.73±0.56)×10-9 and (53±25)×10-9, respectively. The hourly maximum concentrations of PAN and O3 are 3.49×10-9 and 137×10-9. The volume concentrations of PAN and O3 show pronounced diurnal profiles, which are both characterized by much higher values at daytime than at nighttime. In addition, the correlation coefficient between PAN and O3 at daytime (R2=0.52) is notably higher than that at nighttime (R2=0.21). The air masses originating from the south show the highest volume concentration of PAN and O3, with the lowest volume concentration originating from the east. The wind rose plot and cluster analysis of the back trajectories show that the highest concentration of pollutants mainly originates in the southwest. The air massess originating from the east and circulating through the Bohai Sea and coastal areas of the Hebei and Liaoning provinces show the lowest volume concentrations of PAN and O3. The transportation within the boundary layer plays an important role in the concentration distribution of PAN and O3.

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