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1.
Plant Physiol Biochem ; 216: 109166, 2024 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-39366201

RESUMEN

Nitrogen levels and distribution in the rhizosphere strongly regulate the root architecture. Nitrate is an essential nutrient and an important signaling molecule for plant growth and development. Hydroponic experiments were conducted to investigate the differences in endodermal suberization in tobacco (Nicotiana tabacum L.) roots at three nitrate levels. Nitrogen accumulation was detected in the roots, shoots, and xylem sap. Nitrate influx on the root surface was also measured using the non-invasive self-referencing microsensor technique (SRMT). RNA-Seq analysis was performed to identify the genes related to endodermal suberization, nitrate transport, and endogenous abscisic acid (ABA) biosynthesis. The results showed that root length, root-shoot ratio, nitrate influx on the root surface, and NiA and NRT2.4 genes were regulated to maintain the nitrogen nutrient supply in tobacco under low nitrate conditions. Low nitrate levels enhanced root endodermal suberization and hence reduced the apoplastic transport pathway, and genes from the KCS, FAR, PAS2, and CYP86 families were upregulated. The results of exogenous fluridone, an ABA biosynthesis inhibitor, indicated that suberization of the tobacco root endodermis had no relevance to radial nitrate transport and accumulation. However, ABA enhances suberization, relating to ABA biosynthesis genes in the CCD family and degradation gene ABA8ox1.

2.
J Hazard Mater ; 479: 135695, 2024 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-39217922

RESUMEN

The capillary zone plays a crucial role in migration and transformation of pollutants. Light nonaqueous liquids (LNAPLs) have become the main organic pollutant in soil and groundwater environments. However, few studies have focused on the concentration distribution characteristics and quantitative expression of LNAPL pollutants within capillary zone. In this study, we conducted a sandbox-migration experiment using diesel oil as a typical LNAPL pollutant, with the capillary zone of silty sand as the research object. The variation characteristics of LNAPL pollutants (total petroleum hydrocarbon) concentration and environmental factors (moisture content, electrical conductivity, pH, and oxidationreduction potential) were essentially consistent at different locations with the same height. These characteristics differed within range of 10.0-50.0 cm and above 60.0 cm from groundwater. A model for quantitative expression of concentrations was constructed by coupling multiple environmental factors of 968 sets-7744 data via random forest algorithm. The goodness of fit (R2) for both training and test sets was greater than 0.90, and the mean absolute percentage error (MAPE) was less than 16.00 %. The absolute values of relative errors in predicting concentrations at characteristic points were less than 15.00 %. The constructed model can accurately and quantitatively express and predict concentrations in capillary zone.

3.
ACS Appl Mater Interfaces ; 16(36): 48342-48351, 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39216006

RESUMEN

A series of slide-ring polyrotaxanes (SRPs) have been constructed by the solvent-free blending of a ditopic pillar[5]arene (DP5A) and polyisoprene (PIP) after thermal annealing. Solid-state 13C NMR experiments supported the fact that the pillar[5]arene rings of DP5A were threaded by PIP chains to afford physically interlocked networks. Tensile tests revealed that 1% of DP5A can improve the elongation at break from 50 to 239%, the tensile modulus from 2.1 to 3.9 MPa, and the toughness from 0.35 to 4.5 MJ/m3. Impact and puncture resistance experiments show that the DP5A-doped materials exhibit remarkable enhancement of protective and impalement-resistant performance. The samples can be also recycled repeatedly due to their physical crosslinking nature. The important stress delocalization effects have been attributed to the pulley effect of DP5A in the SRP materials, which represents a supramolecular approach for improving the performance of PIP elastomers.

4.
Environ Pollut ; 360: 124777, 2024 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-39173866

RESUMEN

The application of manure and earthworms are frequently used in fertilization practices to improve C, N, and P cycling in soil, which may be adversely affected by roxarsone (ROX), as an organoarsenical pollutant. To effectively address this issue, in this work, the interactive impacts of ROX and earthworm Eisenia foetida on the aggregate formation, input of organic carbon (OC), and changes in the available N and P following 56-day cultivation were systematically investigated. Compared to the control, earthworms increased the mean weight diameter (MWD) of the soil aggregates from 0.6 to 1.1 mm. Thereby, they activated soil enzymes including catalase (CAT), sucrase (SC), urease (UE), and neutral phosphatase (NP), with the soil's pH decreased to 7.1. Consequently, the values of OC, soluble nitrite (NO3-N), and Olsen-P content were respectively increased by 0.78-, 1.69-, and 0.87- folds in the E treatment (14.3 vs. 25.5 g/kg, 12.8 vs. 33.3 mg/kg, and 7.8 vs. 14.6 mg/kg). Although the changes in the R treatment were slight, ROX reduced the earthworm-mediated improvements of soil fertility during the application of the RE treatment compared to the E treatment, i.e., the values of MWD, OC, NO3-N, and Olsen-P were reduced to 0.9 mm, 20.4 g/kg, 25.4 mg/kg, and 11.6 mg/kg, respectively. From the well-fitted structural equation models, it was demonstrated that earthworms enhanced the aggregate formation and nutrient cycling of OC, NO3-N, and Olsen-P, which were inhibited by ROX. Overall, these adverse effects can be offset by earthworm addition, which can play the dual role of monitor and driver for the soil properties. Our work provides insightful strategies for ROX-bearing manure management.


Asunto(s)
Estiércol , Oligoquetos , Roxarsona , Contaminantes del Suelo , Suelo , Oligoquetos/metabolismo , Animales , Suelo/química , Contaminantes del Suelo/metabolismo , Fertilizantes/análisis , Fósforo/metabolismo , Nitrógeno/metabolismo
5.
Front Neurol ; 15: 1295429, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38606276

RESUMEN

Background: To date, the clinical modulation for bone metabolism based on the neuro-bone mass regulation theory is still not popular. The stimulation of nerve systems to explore novel treatments for Postmenopausal osteoporosis (PMOP) is urgent and significant. Preliminary research results suggested that changes brain function and structure may play a crucial role in bone metabolism with PMOP. Thus, we set up a clinical trial to investigate the effect of the combination of repetitive transcranial magnetic stimulation (rTMS) and catgut embedding in acupoints (CEA) for PMOP and to elucidate the central mechanism of this neural stimulation in regulating bone metabolism. Method: This trial is a prospective and randomized controlled trial. 96 PMOP participants will be randomized in a 1:1:1 ratio into a CEA group, an rTMS group, or a combined one. Participants will receive CEA, rTMS, or combined therapy for 3 months with 8 weeks of follow-up. The primary outcomes will be the changes in Bone Mineral Density scores, total efficiency of Chinese Medicine Symptoms before and after treatment. Secondary outcomes include the McGill Pain Questionnaire Short-Form, Osteoporosis Symptom Score, Mini-Mental State Examination, and Beck Depression Inventory-II. The leptin, leptin receptor, and norepinephrine levels of peripheral blood must be measured before and after treatment. Adverse events that occur during the trial will be recorded. Discussion: CEA achieves brain-bone mass regulation through the bottom-up way of peripheral-central while rTMS achieves it through the top-down stimulation of central-peripheral. CEA combined with rTMS can stimulate the peripheral-central at the same time and promote peripheral bone mass formation. The combination of CEA and rTMS may play a coordinating, synergistic, and side-effect-reducing role, which is of great clinical significance in exploring better treatment options for PMOP.Clinical trial registration: https://www.chictr.org.cn/, identifier ChiCTR2300073863.

6.
Sci Total Environ ; 924: 171462, 2024 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-38447732

RESUMEN

The damage caused by petroleum hydrocarbon pollution to soil and groundwater environment is becoming increasingly significant. The vadose zone is the only way for petroleum hydrocarbon pollutants to leak from surface into groundwater. The spatial distribution characteristics of indigenous microorganisms in vadose zone, considering presence of capillary zones, have rarely been reported. To explore the spatial distribution characteristics of indigenous microorganisms in vadose zone contaminated by petroleum hydrocarbons, a one-dimensional column migration experiment was conducted using n-hexadecane as characteristic pollutant. Soil samples were collected periodically from different heights during experiment. Corresponding environmental factors were monitored online. The microbial community structure and spatial distribution characteristics of the cumulative relative abundance were systematically analyzed using 16S rRNA sequencing. In addition, the microbial degradation mechanism of n-hexadecane was analyzed using metabolomics. The results showed that presence of capillary zone had a strong retarding effect on n-hexadecane infiltration. Leaked pollutants were mainly concentrated in areas with strong capillary action. Infiltration and displacement of NAPL-phase pollutants were major driving force for change in moisture content (θ) and electric conductivity (EC) in vadose zone. The degradation by microorganisms results in a downward trend in potential of hydrogen (pH) and oxidation-reduction potential (ORP). Five petroleum hydrocarbon-degrading bacterial phyla and 11 degradable straight-chain alkane bacterial genera were detected. Microbial degradation was strong in the area near edge of capillary zone and locations of pollutant accumulation. Mainly Sphingomonas and Nocardioides bacteria were involved in microbial degradation of n-hexadecane. Single-end oxidation involved microbial degradation of n-hexadecane (C16H34). The oxygen consumed, hexadecanoic acid (C16H32O2) produced during this process, and release of hydrogen ions (H+) were the driving factors for reduction of ORP and pH. The vadose zone in this study considered presence of capillary zone, which was more in line with actual contaminated site conditions compared with previous studies. This study systematically elucidated vertical distribution characteristics of petroleum hydrocarbon pollutants and spatiotemporal variation characteristics of indigenous microorganisms in vadose zone considered presence of capillary zone. In addition, the n-hexadecane degradation mechanism was elucidated using metabolomics. This study provides theoretical support for development of natural attenuation remediation measures for petroleum-hydrocarbon-contaminated soil and groundwater.


Asunto(s)
Contaminantes Ambientales , Petróleo , Contaminantes del Suelo , ARN Ribosómico 16S , Alcanos , Hidrocarburos/metabolismo , Suelo , Oxígeno , Biodegradación Ambiental , Contaminantes del Suelo/análisis , Microbiología del Suelo
7.
Environ Int ; 185: 108517, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38401435

RESUMEN

The organoarsenical feed additive roxarsone (ROX) is a ubiquitous threat due to the unpredictable levels of arsenic (As) released by soil bacteria. The earthworms representing soil fauna communities provide hotspots for As biotransformation genes (ABGs). Nonetheless, the role of gut bacteria in this regard is unclear. In this study, the changes in As speciation, bacterial ABGs, and communities were analyzed in a ROX-contaminated soil (50 mg/kg As in ROX form) containing the earthworm Eisenia feotida. (RE vs. R treatment). After 56 d, earthworms reduced the levels of both ROX and total As by 59 % and 17 %, respectively. The available As content was 10 % lower in the RE than in R treatment. Under ROX stress, the total ABG abundance was upregulated in both earthworm gut and soil, with synergistic effects observed following RE treatment. Besides, the enrichment of arsM and arsB genes in earthworm gut suggested that gut bacteria may facilitate As removal by enhancing As methylation and transport function in soil. However, the bacteria carrying ABGs were not associated with the ABG abundance in earthworm gut indicating the unique strategies of earthworm gut bacteria compared with soil bacteria due to different microenvironments. Based on a well-fit structural equation model (P = 0.120), we concluded that gut bacteria indirectly contribute to ROX transformation and As detoxification by modifying soil ABGs. The positive findings of earthworm-induced ROX transformation shed light on the role of As biomonitoring and bioremediation in organoarsenical-contaminated environments.


Asunto(s)
Arsénico , Oligoquetos , Roxarsona , Contaminantes del Suelo , Animales , Arsénico/análisis , Roxarsona/farmacología , Suelo/química , Bacterias , Biotransformación , Contaminantes del Suelo/análisis
8.
Environ Pollut ; 343: 123275, 2024 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-38163628

RESUMEN

PM2.5-bound metal contaminants are associated with multiple chronic diseases in human. At global level, the contamination status has not been well controlled yet. Here we report findings from a long-term air pollution surveillance in Jinan city of Shandong, China. During 2014-2022, the dynamics and trends of PM2.5-bound heavy metal contaminants were monitored in an industrial area and a downtown area. The surveillance targets included: antimony (Sb), aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), mercury (Hg), lead (Pb), manganese (Mn), nickel (Ni), selenium (Se). The human exposure and health risks were calculated and we found that the health risks of most contaminants showed peak values in autumn and winter. But Al, Mn, Hg and Be were found to result in highest health risk in spring or summer in the downtown area. In the industrial area we identified 100% alarming health index >1 (ranged from 1.12 to 3.35) in autumn and winter. In winter the total non-carcinogenic HI was all above 1 (peak value 2.21). Mn and As together posed >85% non-carcinogenic risk. As and Cd were ranked as major drivers of carcinogenic risks (5.84 × 10-6 and 2.78 × 10-6). Pd and Cd both showed non-negligible environmental levels but risk assessment model for their air-exposure associated non-carcinogenic risks are not yet available. This study updates air pollution data and status for air pollution status in China. This study provides valuable 9 year long-term reference to experimental and field studies in the related fields.


Asunto(s)
Contaminación del Aire , Arsénico , Mercurio , Metales Pesados , Humanos , Cadmio , Contaminación del Aire/análisis , Metales Pesados/análisis , Arsénico/análisis , Carcinógenos , Manganeso , Monitoreo del Ambiente , China/epidemiología , Aluminio , Material Particulado/análisis , Medición de Riesgo
9.
ACS Appl Mater Interfaces ; 16(1): 1616-1627, 2024 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-38126783

RESUMEN

A small amount of terminal polar phase endows natural rubber (NR) with excellent comprehensive properties superior to those of synthetic isoprene rubber. In this work, the comprehensive properties of synthetic rubber were remarkably improved by introducing a stable terminal nanoconfinement structure by combining terminal hydroxyl groups and pentapeptide molecules noncovalently into the same phases. The results show that the stable terminal phases hardly affect the free chain motion but enhance the entanglement. Under cyclic loading, the terminal polar phases undergo hierarchically structural changes such as reversible dissociation of the weak bonds, phase deformation, and crystalline reorganization, all of which dissipate the stress and are beneficial for high strength and extensibility. At the same time, synthetic rubbers demonstrate much superior fatigue resistance and lower hysteresis relative to NR and maintain comparable dimensional stability. This strategy suggests that the comprehensive properties of elastomers can be regulated and upgraded by facile terminal noncovalent interactions.

10.
BMJ Open ; 13(12): e074740, 2023 12 30.
Artículo en Inglés | MEDLINE | ID: mdl-38159952

RESUMEN

INTRODUCTION: The review aims to conduct the first network meta-analysis to comprehensively evaluate the application of multiple acupuncture techniques in patients with postmenopausal osteoporosis, ranking the best acupuncture treatment and providing a reference for clinical treatment extensively. METHODS AND ANALYSIS: Randomised controlled trials of different acupuncture-related therapies for postmenopausal osteoporosis will be searched in the following databases from 1 January 2002 to 31 December 2022, including PubMed, Embase, Cochrane Library, Web of Science, China National Knowledge Infrastructure, VIP Database, Wanfang Database and China Biomedical Literature Database. Overall, clinical efficacy rate, bone mineral density and a Visual Analogue Scale score are used as the primary outcome indicators. In addition, the secondary outcome indicator is adverse reactions. The entire screening process will be conducted by two independent investigators; meanwhile, Stata (V.14.0) and RevMan (V.5.4) will be used to conduct the network meta-analysis. If the data are permissible and feasible, we will also perform meta-regression and subgroup analyses to address the underlying causes of data inconsistency and heterogeneity in the statistical analyses. Besides, to improve the credibility of this network meta-analysis, we will evaluate the quality of evidence in this research according to the GRADE assessment. ETHICS AND DISSEMINATION: Ethics approval is not required for network meta-analyses, which do not involve animals' or people's welfare. The results of this network meta-analysis will be submitted to a recognised journal for publication. PROSPERO REGISTRATION NUMBER: CRD42023401003.


Asunto(s)
Terapia por Acupuntura , Osteoporosis Posmenopáusica , Femenino , Humanos , Terapia por Acupuntura/métodos , Teorema de Bayes , Metaanálisis como Asunto , Metaanálisis en Red , Osteoporosis Posmenopáusica/terapia , Proyectos de Investigación , Revisiones Sistemáticas como Asunto
11.
Zhongguo Zhen Jiu ; 43(10): 1180-3, 2023 Oct 12.
Artículo en Chino | MEDLINE | ID: mdl-37802526

RESUMEN

Ashi points play a significant role in the clinical localization and qualitative diagnosis of acupuncture, as well as in selecting acupoints along the meridians and applying tonifying or reducing techniques. This paper introduces the theoretical basis and existing technical methods of objectification of ashi point diagnosis and treatment. It proposes that using sensory quantitative testing to determine the temperature and tenderness thresholds of ashi points could help to identify the pathological characteristics of "cold" "heat" "deficiency" or "excess" of ashi points. In addition, the possibility of objectification of ashi point diagnosis-treatment plan is explored from three perspectives, precision of selection of ashi point therapy, objectification of effect evaluation of ashi point analgesia, and differentiation of the studies on ashi point analgesic mechanism, aiming to provide new research ideas for the modernization of traditional Chinese acupuncture.


Asunto(s)
Terapia por Acupuntura , Acupuntura , Analgesia , Meridianos , Puntos de Acupuntura
12.
J Orthop Surg Res ; 18(1): 678, 2023 Sep 13.
Artículo en Inglés | MEDLINE | ID: mdl-37705066

RESUMEN

BACKGROUND: Trigger finger is a common condition in the hand, and ultrasound-guided acupotomy for trigger finger has been widely used in recent years. PURPOSE: This study aims to investigate the efficacy and safety of ultrasound-guided acupotomy for trigger finger. METHODS: We searched for relevant studies in the Cochrane Library, China National Knowledge Infrastructure (CNKI), Embase, PubMed, Chinese Biomedical Literature Database (CBM), Wanfang Data, and other resources from their inception to January 2023. Randomized controlled trials of ultrasound-guided acupotomy for trigger finger were included. The meta-analysis was carried out using Review Manager 5.4 and Stata 15.1. RESULTS: Overall, 15 studies with 988 patients were included. The experimental group was treated with ultrasound-guided acupotomy, and the Control group received traditional acupotomy, traditional operation or injection of medication. Meta-analysis showed that the overall clinical effectiveness (OR = 4.83; 95% CI 2.49-9.37; I2 = 73.1%; P < 0.001) in the experimental group was significantly better than that of the control group. And the Visual Analogue Scale (VAS) score (WMD = - 1; 95% CI - 1.24, - 0.76; I2 = 99%; P < 0.001), the QuinneII classification (WMD = - 0.84; 95% CI - 1.28, - 0.39; I2 = 99.1%, P < 0.001), the incidence of complications (RR = 0.26; 95% CI 0.11, 0.63; I2 = 0%, P = 0.003), and the recurrence rate (RR = 0.14; 95% CI 0.03, 0.74; I2 = 0%; P = 0.021) were significantly lower in the experimental group. CONCLUSION: Our systematic review and meta-analysis can prove the effectiveness and safety of ultrasound-guided acupotomy in the treatment of trigger finger, but this still needs to be verified by a clinical standard large sample test.


Asunto(s)
Terapia por Acupuntura , Trastorno del Dedo en Gatillo , Humanos , Trastorno del Dedo en Gatillo/diagnóstico por imagen , Trastorno del Dedo en Gatillo/terapia , Ultrasonografía Intervencional
13.
Sci Total Environ ; 904: 166641, 2023 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-37647954

RESUMEN

With the increasing use of plastics, nano- and micro-plastic (NMP) pollution has become a hot topic in the scientific community. Ubiquitous NMPs, as emerging contaminants, are becoming a global issue owing to their persistence and potential toxicity. Compared with studies of marine and freshwater environments, investigations into the sources, transport properties, and fate of NMPs in soil and groundwater environments remain at a primary stage. Hence, the promotion of such research is critically important. Here, we integrate existing information and recent advancements to compile a comprehensive evaluation of the sources and transport properties of NMPs in soil and groundwater environments. We first provide a systematic description of the various sources and transport behaviors of NMPs. We then discuss the theories (e.g., clean-bed filtration and Derjaguin-Landau-Verwey-Overbeek theories) and models (e.g., single-site and dual-site kinetic retention and transport models) of NMP transport through saturated porous media. Finally, we outline the potential limitations of current research and suggest directions for future research. Overall, this review intends to assimilate and outline current knowledge and provide a useful reference frame to determine the sources and transport properties of NMPs in soil and groundwater environments.

14.
Front Psychiatry ; 14: 1139992, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37304433

RESUMEN

Introduction: Females in the perimenopausal period are susceptible to mood disorders. Perimenopausal panic disorder (PPD) is characterized by repeated and unpredictable panic attacks during perimenopause, and it impacts the patient's physical and mental health and social function. Pharmacotherapy is limited in the clinic, and its pathological mechanism is unclear. Recent studies have demonstrated that gut microbiota is strongly linked to emotion; however, the relation between PPD and microbiota is limitedly known. Methods: This study aimed to discover specific microbiota in PPD patients and the intrinsic connection between them. Gut microbiota was analyzed in PPD patients (n = 40) and healthy controls (n = 40) by 16S rRNA sequencing. Results: The results showed reduced α-diversity (richness) in the gut microbiota of PPD patients. ß-diversity indicated that PPD and healthy controls had different intestinal microbiota compositions. At the genus level, 30 species of microbiota abundance had significantly different between the PPD and healthy controls. In addition, HAMA, PDSS, and PASS scales were collected in two groups. It was found that Bacteroides and Alistipes were positively correlated with PASS, PDSS, and HAMA. Discussion: Bacteroides and Alistipes dysbiosis dominate imbalanced microbiota in PPD patients. This microbial alteration may be a potential pathogenesis and physio-pathological feature of PPD. The distinct gut microbiota can be a potential diagnostic marker and a new therapeutic target for PPD.

15.
Arch Womens Ment Health ; 26(1): 1-10, 2023 02.
Artículo en Inglés | MEDLINE | ID: mdl-36705738

RESUMEN

Premature ovarian insufficiency (POI) appears to be associated with depressive and anxiety symptoms. However, there is a lack of high-quality evidence relating to the risk of patients with POI developing depression or anxiety. Therefore, we conducted a systematic review and meta-analysis to quantify the risk of depressive and anxiety symptoms in women with POI. We searched English and Chinese databases to evaluate the risk of depression and anxiety disorders in patients with POI. The final search date was November 2021. The risk was quantified using meta-analysis, with an estimation of pooled odds ratio (OR) and 95% confidence interval (CI). Sources of heterogeneity were explored by subgroup analysis. A total of seven primary studies with 1316 individuals were included, five of which were related to depression and six to anxiety disorders. All included articles were case-control studies of high quality. Patients with POI were associated with a higher odds of depression and anxiety (depression: OR = 3.33, 95% CI = 2.31-4.81, P < 0.001; anxiety: OR = 4.89, 95% CI = 3.28-7.30, P < 0.001). Subgroup analysis also indicated that patients with POI are at a higher risk of anxiety and depression. POI appears to be associated with a high risk of depression and anxiety. Early psychosocial assessment and regular screening of patients with POI are also necessary. In addition, it is important to consider the mental health of patients with POI.


Asunto(s)
Ansiedad , Depresión , Insuficiencia Ovárica Primaria , Femenino , Humanos , Ansiedad/epidemiología , Salud Mental , Insuficiencia Ovárica Primaria/complicaciones , Insuficiencia Ovárica Primaria/epidemiología , Depresión/epidemiología
16.
Environ Pollut ; 313: 120059, 2022 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-36049576

RESUMEN

The process improvement, a pilot remediation test and the decontamination mechanism of microwave-induced steam distillation (MISD) for petroleum hydrocarbons (PHs) removal were conducted. Processes of multistage steam distillation and carbon reinforcement were compared to determine the best remediation process. Pilot project was then carried out to explore the applicability of MISD in site-scale remediation. The remediation efficiency, procedures and influencing factors of site-scale MISD project were studied by monitoring variations of soil moisture, temperature and PHs concentrations. Furthermore, the decontamination mechanisms of PHs were clarified based on kinetic analysis. The results showed that the multistage steam distillation could improve 10%∼15% remediation efficiency, and the carbon reinforcement could shorten remediation duration of each steam distillation stage by 50%. Pilot MISD project adopted multistage steam distillation process and went through four (initial, rapid heating-up, gentle heating-up and quasi-equilibrium) remediation stages (overall temperature ≤100 °C). The final PHs removal rate was about 60%, which would get better with greater proportion of low boiling points components and stronger vapor extraction. Kinetic studies showed that PHs was removed by steam stripping and limited by intraparticle diffusion in the "steam distillation zone", while local high temperature (>100 °C) greatly improved PHs volatilization and provided activation energy for PHs desorbed and degraded in the "selective heating zone".


Asunto(s)
Petróleo , Contaminantes del Suelo , Carbono , Destilación , Hidrocarburos , Cinética , Microondas , Petróleo/análisis , Proyectos Piloto , Suelo , Contaminantes del Suelo/análisis , Vapor/análisis
17.
Environ Res ; 213: 113633, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-35700766

RESUMEN

The bentonite colloid produced in the deep geological repository of high-level radioactive waste can directly affect the migration of radionuclide strontium when it acts on claystone. The adsorption characteristics of strontium were investigated on claystone with the presence or absence of bentonite colloids from the Suhongtu area of China. The effects of different influencing factors, such as pH and solid content, on the adsorption process were investigated by batch adsorption experiments, and spectroscopic techniques were used to characterize the samples before and after adsorption of strontium. The results show that the presence of bentonite colloids can promote the adsorption of strontium on claystone under alkaline conditions. and the general order kinetic model provided the best fit to the experimental data. Strontium is adsorbed on the surface of claystone and bentonite colloid by ion exchange and surface complexation. Most of the Sr2+ formed SrCO3 with CO32- after ion exchange with Ca2+ and Mg2+ in plagioclase and dolomite, and a small amount of Sr2+ was adsorbed by complexation with -OH, Al-O and Si-O. These results provide a scientific basis for predicting the migration of strontium in subsurface porous media and the siting of high-level radioactive waste repositories.


Asunto(s)
Residuos Radiactivos , Adsorción , Bentonita/química , Coloides/química , Residuos Radiactivos/análisis , Estroncio/química
18.
J Environ Manage ; 317: 115366, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35636110

RESUMEN

Due to the leaching of capillary water, the petroleum pollutants initially trapped in vadose zone may migrate to lower aquifer, thus increasing the risk of groundwater pollution. In order to explore the effect of capillary leaching on toluene-contaminated soil and the relationship between toluene concentration (TC) and environmental factors (EFs) during the leaching process, the sterilized and non-sterilized soil column experiments were designed. The EFs were used to estimate TC. The results showed that the difference between leaching and volatilization rates directly determined the changing trend of toluene concentration in capillary water. The toluene concentration in the medium always showed decreasing trend due to leaching. The indigenous microbial community structure of the non-sterilized soil column was analyzed by 16S rRNA sequencing. It was found that indigenous microorganisms could degrade toluene after 33.0 days of acclimatation. The microbial population was dominated by bacteria, among them the Ellin6055 strain and Pseudomonas, Pseudoxanthomonas, Cupriavidus, Bdellovibrio, Sphingobium, Phenylobacterium, Ramlibacter, Bradyrhizobium, Shinella genera. The Pseudomonas was the most crucial bacterial genus that degraded toluene. Indigenous microbial degradation was the fundamental reason for strong response relationship. Furthermore, we suggested a relationship of function between environmental factors (pH, DO, ORP) and time (t) for toluene attenuation: C0+ln(eAtαBγCß)=CToluene, (α, ß, γ represent the pH, DO, and ORP in leaching capillary water, respectively; A, B, and C represent undetermined coefficients), and the fitting coefficient R2 > 0.950. This relationship can only characterize the attenuation process of capillary zone leaching on toluene. However, it may still be utilized to give a theoretical foundation for understanding the dynamic of pollutant concentration change processes under specific environmental factors.


Asunto(s)
Contaminantes del Suelo , Contaminantes Químicos del Agua , Bacterias/metabolismo , Biodegradación Ambiental , ARN Ribosómico 16S/genética , Suelo , Contaminantes del Suelo/análisis , Tolueno/metabolismo , Agua/metabolismo , Contaminantes Químicos del Agua/análisis
19.
Sci Total Environ ; 821: 153344, 2022 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-35085626

RESUMEN

Rice-wheat cropping system (RWCS), the major rice-based cropping system, constitutes a significant source of N-related greenhouse gas (GHG) emission due to the unique wet-dry alternation process. Biochar is often highlighted as a potential solution for reducing fertilizer N losses, hence, understanding its effects on Ngr emissions (mainly NH3 and N2O) under wet-dry conditions is critical to inform strategies for GHG mitigation. This study investigated the responses of NH3 and N2O emissions to biochar amendments during rice and wheat seasons based on in situ measurements under ten-year successive straw biochar application in RWCS. Our results indicated that 43.7% and 89.9% of N2O and NH3 emissions were emitted during rice season and 56.3% and 10.1% during wheat season, respectively. Long-term biochar amendment was found to play significant role in mitigating NH3 emissions (38.6-43.9%), which could be attributed to the disappearance of liming effect of aged-biochar on flooding water and decreased NH4+ concentrations in the soil. However, considerable variation of N2O emissions were observed in RWCS. Biochar showed a significant decreasing effect on the net global warming potential related to N2O and NH3 emissions (GWPN) in rice season (16.1-89.6%), and slight increased tendency in wheat season (1.43-13.1%) primarily due to its positive effects on N2O emission. Biochar amendment mainly BC22.5, significantly increased above-ground yields by 9.22% in rice season. Thus, it is a low carbon-producing and sustainable crop management method that can support crop production, C sequestration, and GHG mitigation in rice season under RWCS from the viewpoint of the Ngr mitigation. Our results suggest that emission patterns of N2O and NH3 varied with wet-dry alternation under the disturbance of long-term biochar amendment in RWCS; moreover, long-term biochar application exhibited significant potential for mitigating soil Ngr losses in rice season for RWCS.


Asunto(s)
Oryza , Agricultura/métodos , Carbón Orgánico , China , Calentamiento Global , Óxido Nitroso/análisis , Estaciones del Año , Suelo , Triticum
20.
Polymers (Basel) ; 13(24)2021 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-34960958

RESUMEN

The tuning of binding modes of polar groups is the key step to mimicking the structure and properties of natural rubber through the molecular design of synthetic polyisoprenes. Herein, the ordering and binding distances of oligopeptides could be altered systematically by changing their lengths and distribution along the polyisoprene chain, which impose huge impacts on the mechanical properties and chain dynamics of green rubber. In detail, a series of peptide-functionalized polyisoprenes with terminal blocks (B-2A-PIP, B-3A-PIP) or random sequences (R-2A-PIP, R-3A-PIP) are fabricated by using dipeptides (2A) or tripeptides (3A) as crosslinkers to explore the mechanism of terminal interaction on mechanism properties and chain dynamics. B-4A-PIP and R-4A-PIP served as control samples. It is found that the increased oligopeptide length and the block distribution improves the mechanical properties and confine the chain movement by elevate the contents of ordered and compact microstructures, which is indicated by XRD, broadband dielectric spectroscopy (BDS) and consistent with the result of molecular dynamics simulation. New relaxation signals belonging to oligopeptide aggregates are found which showed elevated dielectric strengths upon temperatures increase. Additionally, it also reveals that the binding modes of oligopeptide do not significantly influence the entanglements of polyisoprene.

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