Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 136
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Mol Cancer ; 23(1): 203, 2024 Sep 18.
Artigo em Inglês | MEDLINE | ID: mdl-39294640

RESUMO

Cancer cells undergo significant metabolic reprogramming to support their rapid growth and survival. This study examines important metabolic pathways like glycolysis, oxidative phosphorylation, glutaminolysis, and lipid metabolism, focusing on how they are regulated and their contributions to the development of tumors. The interplay between oncogenes, tumor suppressors, epigenetic modifications, and the tumor microenvironment in modulating these pathways is examined. Furthermore, we discuss the therapeutic potential of targeting cancer metabolism, presenting inhibitors of glycolysis, glutaminolysis, the TCA cycle, fatty acid oxidation, LDH, and glucose transport, alongside emerging strategies targeting oxidative phosphorylation and lipid synthesis. Despite the promise, challenges such as metabolic plasticity and the need for combination therapies and robust biomarkers persist, underscoring the necessity for continued research in this dynamic field.


Assuntos
Metabolismo Energético , Terapia de Alvo Molecular , Neoplasias , Humanos , Neoplasias/metabolismo , Neoplasias/patologia , Neoplasias/tratamento farmacológico , Neoplasias/genética , Animais , Redes e Vias Metabólicas , Microambiente Tumoral , Glicólise , Metabolismo dos Lipídeos , Fosforilação Oxidativa , Antineoplásicos/farmacologia , Antineoplásicos/uso terapêutico
2.
J Transl Med ; 22(1): 15, 2024 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-38172946

RESUMO

Breast cancer (BC) is a multifaceted disease characterized by distinct molecular subtypes and varying responses to treatment. In BC, the phosphatidylinositol 3-kinase (PI3K) pathway has emerged as a crucial contributor to the development, advancement, and resistance to treatment. This review article explores the implications of the PI3K pathway in predictive, preventive, and personalized medicine for BC. It emphasizes the identification of predictive biomarkers, such as PIK3CA mutations, and the utility of molecular profiling in guiding treatment decisions. The review also discusses the potential of targeting the PI3K pathway for preventive strategies and the customization of therapy based on tumor stage, molecular subtypes, and genetic alterations. Overcoming resistance to PI3K inhibitors and exploring combination therapies are addressed as important considerations. While this field holds promise in improving patient outcomes, further research and clinical trials are needed to validate these approaches and translate them into clinical practice.


Assuntos
Neoplasias da Mama , Fosfatidilinositol 3-Quinase , Humanos , Feminino , Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias da Mama/patologia , Medicina de Precisão , Inibidores de Fosfoinositídeo-3 Quinase/uso terapêutico , Mutação/genética , Classe I de Fosfatidilinositol 3-Quinases , Proteínas Proto-Oncogênicas c-akt/metabolismo
3.
Chem Rec ; 24(1): e202300141, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37724006

RESUMO

Electrical conductivity is very important property of nanomaterials for using wide range of applications especially energy applications. Metal-organic frameworks (MOFs) are notorious for their low electrical conductivity and less considered for usage in pristine forms. However, the advantages of high surface area, porosity and confined catalytic active sites motivated researchers to improve the conductivity of MOFs. Therefore, 2D electrical conductive MOFs (ECMOF) have been widely synthesized by developing the effective synthetic strategies. In this article, we have summarized the recent trends in developing the 2D ECMOFs, following the summary of potential applications in the various fields with future perspectives.

4.
Chem Rec ; 24(1): e202300155, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37435960

RESUMO

In recent years, flexible and wearable electronics such as smart cards, smart fabrics, bio-sensors, soft robotics, and internet-linked electronics have impacted our lives. In order to meet the requirements of more flexible and adaptable paradigm shifts, wearable products may need to be seamlessly integrated. A great deal of effort has been made in the last two decades to develop flexible lithium-ion batteries (FLIBs). The selection of suitable flexible materials is important for the development of flexible electrolytes self-supported and supported electrodes. This review is focused on the critical discussion of the factors that evaluate the flexibility of the materials and their potential path toward achieving the FLIBs. Following this analysis, we present how to evaluate the flexibility of the battery materials and FLIBs. We describe the chemistry of carbon-based materials, covalent-organic frameworks (COFs), metal-organic frameworks (MOFs), and MXene-based materials and their flexible cell design that represented excellent electrochemical performances during bending. Furthermore, the application of state-of-the-art solid polymer and solid electrolytes to accelerate the development of FLIBs is introduced. Analyzing the contributions and developments of different countries has also been highlighted in the past decade. In addition, the prospects and potential of flexible materials and their engineering are also discussed, providing the roadmap for further developments in this fast-evolving field of FLIB research.

5.
Curr Genomics ; 25(5): 343-357, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39323624

RESUMO

The MALAT1, a huge non-coding RNA, recently came to light as a multifaceted regulator in the intricate landscape of breast cancer (BC) progression. This review explores the multifaceted functions and molecular interactions of MALAT1, shedding light on its profound implications for understanding BC pathogenesis and advancing therapeutic strategies. The article commences by acknowledging the global impact of BC and the pressing need for insights into its molecular underpinnings. It is stated that the core lncRNA MALAT1 has a range of roles in both healthy and diseased cell functions. The core of this review unravels MALAT1's multifaceted role in BC progression, elucidating its participation in critical processes like resistance, invasion, relocation, and proliferating cells to therapy. It explores the intricate mechanisms through which MALAT1 modulates gene expression, interacts with other molecules, and influences signalling pathways. Furthermore, the paper emphasizes MALAT1's clinical significance as a possible prognostic and diagnostic biomarker. Concluding on a forward-looking note, the review highlights the broader implications of MALAT1 in BC biology, such as its connections to therapy resistance and metastasis. It underscores the significance of deeper investigations into these intricate molecular interactions to pave the way for precision medicine approaches. This review highlights the pivotal role of MALAT1 in BC progression by deciphering its multifaceted functions beyond the genome, offering profound insights into its implications for disease understanding and the potential for targeted therapeutic interventions.

6.
J Environ Manage ; 369: 122276, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39197345

RESUMO

This research investigated the mechanisms and contextual factors influencing the relationship between servant leadership tailored to specific environments and environmental citizenship behavior, considering the Conservation of Resource Theory as a theoretical lens. Data collection was collected from 300 employees and their supervisors, including several organizations within the Pakistani Hospitality and Tourism sector, and the data underwent analysis using PLS-SEM. Empirical findings showed that the relationship between environmental-specific servant leadership and organizational environmental citizenship behavior is mediated by harmonious environmental passion. The green work climate positively moderates the indirect effects of harmonious environmental passion on organizational environmental citizenship behavior, suggesting that this effect is strengthened when employees have a higher green work climate than with a lower green work climate. Guidelines for future research are provided.


Assuntos
Liderança , Turismo , Paquistão , Humanos , Cultura Organizacional , Local de Trabalho/psicologia
7.
Breast Cancer Res Treat ; 200(3): 305-321, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37289340

RESUMO

BACKGROUND: Breast cancer (BC) is a complex disease with various subtypes and genetic alterations that impact DNA repair pathways. Understanding these pathways is essential for developing effective treatments and improving patient outcomes. AREA COVERED: This study investigates the significance of DNA repair pathways in breast cancer, specifically focusing on various pathways such as nucleotide excision repair, base excision repair, mismatch repair, homologous recombination repair, non-homologous end joining, fanconi anemia pathway, translesion synthesis, direct repair, and DNA damage tolerance. The study also examines the role of these pathways in breast cancer resistance and explores their potential as targets for cancer treatment. CONCLUSION: Recent advances in targeted therapies have shown promise in exploiting DNA repair pathways for BC treatment. However, much research is needed to improve the efficacy of these therapies and identify new targets. Additionally, personalized treatments that target specific DNA repair pathways based on tumor subtype or genetic profile are being developed. Advances in genomics and imaging technologies can potentially improve patient stratification and identify biomarkers of treatment response. However, many challenges remain, including toxicity, resistance, and the need for more personalized treatments. Continued research and development in this field could significantly improve BC treatment.


Assuntos
Neoplasias da Mama , Humanos , Feminino , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Reparo do DNA , Dano ao DNA , Mutação , Recombinação Genética
8.
Curr Opin Nephrol Hypertens ; 32(2): 153-164, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36683540

RESUMO

PURPOSE OF REVIEW: Hypertensive disorders of pregnancy remain a highly morbid condition that affects both the mother and fetus, complicate approximately 10% of pregnancies worldwide, and contribute to immediate and long-term cardiovascular outcomes. There is still much to learn regarding pathogenesis and treatment goals. RECENT FINDINGS: There is updated information on the pathogenesis of preeclampsia and treatment thresholds for HTN in pregnancy. l-Kynurenine, a metabolite of the essential amino acid l-tryptophan, has been implicated in preeclampsia as decreased levels were found in a uninephrectomized pregnant mouse model of preeclampsia, where replacement of l-kynurenine rescued the preeclamptic state. Further, data from CHIPS (The Control of HTN in Pregnancy Study) and CHAP (Chronic HTN and Pregnancy) trials demonstrate not only the safety of lowering blood pressure to either a diastolic goal of 85 mmHg (CHIPS) or less than 160/105 mmHg (CHAP) without detriment to the fetus but the CHAPS trial has also shown a decrease in the rate of preeclampsia in the treatment group. SUMMARY: We will summarize the different types of hypertensive disorders in pregnancy, updates on the pathogenesis of preeclampsia, and appropriate HTN management based on the latest evidence in order to better care for mother and child.


Assuntos
Hipertensão , Pré-Eclâmpsia , Gravidez , Feminino , Animais , Camundongos , Humanos , Pré-Eclâmpsia/terapia , Cinurenina , Hipertensão/tratamento farmacológico , Feto
9.
Support Care Cancer ; 31(7): 418, 2023 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-37354379

RESUMO

The impact of the post-COVID-19 pandemic on individuals with colorectal cancer (CRC) was evaluated in a study with 465 cases and controls. Participants completed a questionnaire, and data analysis was conducted using SPSS software. Results showed a higher prevalence of emotional stress symptoms such as fear, depression, and worry among cases compared to controls. Additionally, cases reported greater physiological stress symptoms, such as low energy levels. The results also indicated that cases had higher rates of racing thoughts, pessimism, and avoidance of responsibilities compared to controls. These findings highlight the significant negative impact of the pandemic on individuals with CRC and the need for prompt attention and support.


Assuntos
COVID-19 , Disfunção Cognitiva , Neoplasias Colorretais , Humanos , Saúde Mental , Pandemias , Neoplasias Colorretais/epidemiologia , Depressão/epidemiologia , Depressão/etiologia , Ansiedade/epidemiologia , Ansiedade/etiologia
10.
Chron Respir Dis ; 20: 14799731231157770, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37564035

RESUMO

Aim: This study retrospectively analyses the impact of the 1st year of the COVID-19 pandemic on route of presentation and staging in lung cancer compared to the 2 years before and after implementation of the Leicester Optimal Lung Cancer Pathway (LOLCP) in Leicester, United Kingdom. Method: Electronic databases and hospital records were used to identify all patients diagnosed with lung cancer in 2018 (pre-LOLCP), 2019 (post-LOLCP), and March 2020-2021 (post-COVID-19 lockdown). Information regarding patient characteristics, performance status, stage, and route of diagnosis was documented and analysed. Emergency presentation was defined as diagnosis of new lung cancer being made after unscheduled attendance to urgent or emergency care facility. Results: Following implementation of the LOLCP pathway, there was a significant decrease in emergency presentations from 26.8 to 19.6% (p = 0.002) with a stage shift from 33.9% early stage disease to 40.3%. These improved outcomes were annulled during the COVID-19 pandemic, with emergency presentations increasing to 38.9% (p < 0.001) and a reduction in early-stage lung cancer diagnoses to 31.5%. There was a 61% decline in 2 week wait referrals but no significant decline in the LOLCP direct-to-CT referrals. Conclusion: We have demonstrated a significant increase in late-stage lung cancer diagnoses and emergency presentations during the first year of the COVID-19 pandemic. The causes for these changes are likely to be multifactorial. The long-term effect on lung cancer mortality remains to be seen and is an important focus of future study.


Assuntos
COVID-19 , Neoplasias Pulmonares , Humanos , COVID-19/epidemiologia , Neoplasias Pulmonares/epidemiologia , Estadiamento de Neoplasias , Estudos Retrospectivos , Pandemias , Controle de Doenças Transmissíveis , Pulmão
11.
Small ; 18(32): e2202060, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35843882

RESUMO

The update of electrolytes from a liquid state to a solid state is considered effective in improving the safety and energy density of lithium-ion batteries (LIBs). Although numerous efforts have been made, solid-state electrolytes' (SSEs) insufficient charge transfer capability remains a significant obstruction to practical applications. Herein, a fireproof and anion-immobilized composite electrolyte is designed by solidifying carbonate electrolyte, exhibiting superior Li-ion conductivity (11.5 mS cm-1 at 30 °C) and Li-ion transference number (0.90), which endows LIBs excellent rate capability and cycling stability. Elaborate characteristics and theoretical calculations demonstrate the presence of robust anion-molecule coordination (composed of lithium bond and Coulomb force) enables a more efficient ion transport, where the mobility of Li+ ion is enhanced meanwhile the anions are immobilized. This work highlights how the strong interactions between electrolyte components can be used to simultaneously regulate the migration of Li+ ion and anion, and realize a one-step conversion of inflammable liquid-state electrolyte to nonflammable solid-state electrolyte.

12.
Physiol Plant ; 174(6): e13806, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36271716

RESUMO

Drought stress is a serious issue that affects agricultural productivity all around the world. Several researchers have reported using plant growth-promoting endophytic bacteria to enhance the drought resistance of crops. However, how endophytic bacteria and endophytic fungi are effectively stimulating plant growth under drought stress is still largely unknown. In this article, a global meta-analysis was undertaken to compare the plant growth-promoting effects of bacterial and fungal endophytes and to identify the processes by which both types of endophytes stimulate plant growth under drought stress. Moreover, this meta-analysis enlightens how plant growth promotion varies across crop types (C3 vs. C4 and monocot vs. dicot), experiment types (in vitro vs. pots vs. field), and the inoculation methods (seed vs. seedling). Specifically, this research included 75 peer-reviewed publications, 170 experiments, 20 distinct bacterial genera, and eight fungal classes. On average, both endophytic bacterial and fungal inoculation increased plant dry and fresh biomass under drought stress. The effect of endophytic bacterial inoculation on plant dry biomass, shoot dry biomass, root length, photosynthetic rate, leaf area, and gibberellins productions were at least two times greater than that of fungal inoculation. In addition, under drought stress, bacterial inoculation increased the proline content of C4 plants. Overall, the findings of this meta-analysis indicate that both endophytic bacterial and fungal inoculation of plants is beneficial under drought conditions, but the extent of benefit is higher with endophytic bacteria inoculation but it varies across crop type, experiment type, and inoculation method.


Assuntos
Secas , Estresse Fisiológico , Desenvolvimento Vegetal , Endófitos , Plantas/microbiologia , Bactérias , Fungos
13.
Ecotoxicol Environ Saf ; 234: 113385, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35278995

RESUMO

In semi-arid regions, post-restoration vegetation recovery on abandoned agricultural lands often fails due to inherently low organic matter content and poor soil fertility conditions, including phosphorus (P). As such, amending these soils with controlled release P fertilizer, especially with suitable P solubilizing bacteria (PSB) may promote plant growth and productivity by stimulating biological P fertility. To this aim, a pot study was performed to evaluate the agronomic potential of maize and soil biological P pools, using encapsulated (ENRP) and non-encapsulated (NRP) nano-rock phosphate as the P fertilizer source, on reclaimed agricultural soil in the presence and absence of PSB inoculant. The experiment was setup following a 3 × 2 factorial arrangement with four replicates. Without PSB, NRP treatment showed marginal positive effects on plant growth, P nutrition and P use efficiency (PUE) compared to control treatment. Although larger gains with NRP treatment were more noticeable under PSB inoculation, ENRP was the most convenient slow-release P fertilizer, increasing plant growth, P nutrition and grain yield compared to all treatments. Importantly, PSB inoculation with ENRP resulted in significantly higher increase in soil CaCl2-P (8.91 mg P kg soil-1), citrate-P (26.98 mg P kg soil-1), enzyme-P (18.98 mg P kg soil-1), resin-P (11.41 mg P kg soil-1), and microbial-P (18.94 mg P kg soil-1), when compared to all treatment combinations. Although a decrease in soil HCl-P content was observed with both types of P fertilizer, significant differences were found only with PSB inoculation. A significant increase in soil biological P pools could be due to the higher specific area and crystalline structure of nano materials, providing increased number of active sites for PSB activity in the presence of biobased encapsulated shell. Furthermore, the increase in PSB abundance, higher root carboxylate secretions, and decreased rhizosphere pH in response to nano-structured P fertilizer, implies greater extension of rhizosphere promoting greater P mobilization and/or solubilization, particularly under PSB inoculated conditions. We conclude that cropping potential of abandoned agricultural lands can be enhanced by the use of nano-rock phosphate in combination with PSB inoculant, establishing a favorable micro-environment for higher plant growth and biochemical P fertility.

14.
Environ Monit Assess ; 194(10): 692, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35984532

RESUMO

Groundwater is the drinking water source for the majority of rural settlements of district Nowshera, Khyber Pakhtunkhwa, Pakistan. The study aimed to analyze the groundwater quality and its vulnerability to pollution and to develop its spatial distribution mapping. For this purpose, forty-eight groundwater samples were collected from dug wells, tube wells, and hand pumps of sixteen villages and analyzed for physicochemical parameters. The XY coordinates of the sample's sources were marked by Magellan Triton 1500 handheld global positioning system (GPS). The results were compared with WHO and Pak-EPA guidelines. The results of the majority of selected parameters were found within the WHO and Pak-EPA guidelines; however, in certain areas the concentration of total dissolved solids (TDS), chlorides (Cl-), and alkalinity were higher than the guideline limits. Based on cumulative water quality the excellent water quality prevails over an area of 376 km2 (21% of district area), good water quality 726 km2 (42%), poor 424 km2 (24%), very poor 116 km2 (6%), and unfit for drinking 84 km2 (4%). The water of the Nizampur and Rashaki areas were categorized unfit for drinking. The groundwater quality of nearly one-half of the district varies from poor to very poor, and the soil type and vadose zone sediment/material was found the key reason for groundwater contamination. Based on the infiltration capacity of vadose zone material, the study area was divided into four water pollution vulnerable zones. The low vulnerable zone covers an area of 104 km2, moderate 862 km2, high 667 km2, and very high 93 km2. The most important factor which determines the vulnerability of the groundwater to contamination is the vadose zone material/sediment which in turn determines the soil infiltration capacity. The generated groundwater susceptibility and water quality maps provide critical information for identifying optimal locations for supply wells.


Assuntos
Água Subterrânea , Poluentes Químicos da Água , Monitoramento Ambiental/métodos , Paquistão , Solo , Poluentes Químicos da Água/análise , Qualidade da Água , Abastecimento de Água
15.
Pak J Pharm Sci ; 35(6(Special)): 1779-1786, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36861243

RESUMO

Controlled release in drug release kinetics denotes reproducibility and predictability, implying that drug release from delivery devices follows a kinetically predictable and repeatable rate profile from dose to dose. In the current study controlled release tablets of famotidine were prepared by direct compression technique using Eudragit RL 100 polymer. Four different formulations of controlled release tablets of famotidine as (F1, F2, F3 and F4) were prepared by adding different drug to polymer ratio. The pre compression and the post compression of the formulation, characteristics were compared. All results obtained were within the specified standard limits. FTIR studies showed that both the drug and the polymer were compatible. In vitro dissolution study were conducted by Method II (Paddle Method) in phosphate buffer (pH 7.4), at 100rpm. Power law kinetic model was applied for drug release mechanism. The difference similarity of the dissolution profile was determined. The formulation F1 and F2 were released 97 and 96 % in 24 hours and other formulations F3 and F4 were released subsequently 93% and 90% in 24 hours. The results showed that incorporation of Eudragit RL 100 in the formulation of controlled release tablets prolong the drug release rates for 24 hours. The release mechanism was Non-Fickian diffusion mechanism. It was deducted from the current study that the Eudragit RL 100 can be efficiently incorporated in the formulation of controlled release dosage forms with predictable kinetics.


Assuntos
Famotidina , Polímeros , Preparações de Ação Retardada , Reprodutibilidade dos Testes , Comprimidos
16.
Physiol Plant ; 172(2): 463-476, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32949405

RESUMO

Rhizobacteria containing 1-aminocyclopropane-1-carboxylic acid-deaminase (ACC-deaminase) and exopolysaccharides (EPS) activity are important to induce stress tolerance in plants. The present study was conducted to screen and characterize plant growth-promoting rhizobacteria (PGPR) with ACC-deaminase and EPS-producing activity for improving maize growth under drought stress. Eighty-five rhizobacterial strains were isolated from the rain-fed areas, among those 69 isolates were able to utilize ACC and 31 strains were found positive for EPS production. These strains containing ACC-deaminase and/or EPS-producing activity were subjected to drought tolerance assay by inducing water stress in media using polyethylene glycol 6000. Based on results of the drought tolerance bioassay, 12 most prominent strains were selected to evaluate their growth-promoting abilities in maize under water-stressed conditions by conducting jar trial. The impact of strains on maize growth parameters was variable. Strains with co-existence of ACC-deaminase and EPS-producing activity showed comparatively better results than those with either ACC-deaminase or EPS-producing activity only. These strains were also significantly better in improving the plant physiological parameters including photosynthesis rate, stomatal conductance, vapor pressure, water-use efficiency and transpiration rate. The strain D3 with co-existence of ACC-deaminase and EPS-producing activity was significantly better in colonizing maize roots, improving plant growth and physiological parameters. The strain was named as Bacillus velezensis strain D3 (accession number MT367633) as confirmed through results of 16S rRNA partial gene sequencing. It is concluded that the strains with co-existence of ACC-deaminase and EPS-producing activity could be better suited for improving crop growth and physiology under drought stress.


Assuntos
Secas , Zea mays , Bacillus , Carbono-Carbono Liases , Raízes de Plantas , RNA Ribossômico 16S , Microbiologia do Solo
17.
Environ Res ; 202: 111789, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34333013

RESUMO

Greenhouse gaseous (GHGs) emissions from cropland soils are one of the major contributors to global warming. However, the extent and pattern of these climatic breakdowns are usally determined by the management practices in-place. The use of biochar on cropland soils holds a great promise for increasing the overall crop productivity. Nevertheless, biochar application to agricultural soils has grown in popularity as a strategy to off-set the negative feedback associated with agriculture GHGs emissions, i.e., CO2 (carbon dioxide), CH4 (methane), and N2O (nitrous oxide). Despite increasing efforts to uncover the potential of biochar to mitigate the farmland GHGs effects, there has been little synthesis of how different types of biochar affect GHGs fluxes from cropland soils under varied experimental conditions. Here, we presented a meta-analysis of the interactions between biochar and GHGs emissions across global cropland soils, with field experiments showing the strongest GHG mitigation potential, i.e. CO2 (RR = -0.108) and CH4 (RR = -0.399). The biochar pyrolysis temperature, feedstock, C: N ratio, and pH were also found to be important factors influencing GHGs emissions. A prominent reduction in N2O (RR = -0.13) and CH4 (RR = -1.035) emissions was observed in neutral soils (pH = 6.6-7.3), whereas acidic soils (pH ≤ 6.5) accounted for the strongest mitigation effect on CO2 compared to N2O and CH4 emissions. We also found that a biochar application rate of 30 t ha-1 was best for mitigating GHGs emissions while achieving optimal crop yield. According to our meta-analysis, maize crop receiving biochar amendment showed a significant mitigation potential for CO2, N2O, and CH4 emissions. On the other hand, the use of biochar had shown significant impact on the global warming potential (GWP) of total GHGs emissions. The current data synthesis takes the lead in analyzing emissions status and mitigation potential for three of the most common GHGs from cropland soils and demonstrates that biochar application can significantly reduce the emissions budget from agriculture.


Assuntos
Gases de Efeito Estufa , Agricultura , Carvão Vegetal , Solo
18.
J Environ Manage ; 295: 113119, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34216897

RESUMO

To achieve zero carbon or achieving carbon neutrality target is of great importance to many countries around the globe especially post Paris climate agreement. This study, unlike previous studies, evaluates the role of environmental policy, green innovation, composite risk index, and renewable energy R&D in achieving carbon neutrality targets for G7 economies from 1990 to 2019. The results confirmed the validity of the EKC hypothesis for G7 economies. Further, the result shows that environmental policy, green innovation, composite risk index, and renewable energy R&D help control carbon emissions. In contrast, income reveals a positive influence on environmental degradation. Furthermore, bidirectional causality has been reported in environmental policy, composite risk index, green innovation, and the CO2 emissions, while unidirectional causality running from GDP and renewable energy R&D to CO2 emissions. Based on the empirical findings, it is suggested that environmental policies should be strengthened, promote green innovation and renewable energy research and development expenditures, and political stability and institutional quality must be stabilized to lowers sectoral risks that would help a sustainable environment.


Assuntos
Desenvolvimento Econômico , Política Ambiental , Carbono , Dióxido de Carbono , Energia Renovável
19.
J Environ Manage ; 285: 112170, 2021 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-33607561

RESUMO

Organic amendments (animal manure and biochar) to agricultural soils may enhance soil organic carbon (SOC) contents, improve soil fertility and crop productivity but also contribute to global warming through nitrous oxide (N2O) emission. However, the effects of organic amendments on N2O emissions from agricultural soils seem variable among numerous research studies and remains uncertain. Here, eighty-five publications (peer-reviewed) were selected to perform a meta-analysis study. The results of this meta-analysis study show that the application of animal manure enhanced N2O emissions by 17.7%, whereas, biochar amendment significantly mitigated N2O emissions by 19.7%. Moreover, coarse textured soils increased [lnRR‾ = 182.6%, 95% confidence interval (CI) = 151.4%, 217.7%] N2O emission after animal manure, in contrast, N2O emission mitigated by 7.0% from coarse textured soils after biochar amendment. In addition, this study found that 121-320 kg N ha-1 and ⩽ 30 T ha-1 application rates of animal manure and biochar mitigated N2O emissions by 72.3% and 22.5%, respectively. Soil pH also played a vital role in regulating the N2O emissions after organic amendments. Furthermore, > 10 soil C: N ratios increased N2O emissions by 121.4% and 27.6% after animal and biochar amendments, respectively. Overall, animal manure C: N ratios significantly enhanced N2O emissions, while, biochar C: N ratio had not shown any effect on N2O emissions. Overall, average N2O emission factors (EFs) for animal manure and biochar amendments were 0.46% and -0.08%, respectively. Thus, the results of this meta-analysis study provide scientific evidence about how organic amendments such as animal manure and biochar regulating the N2O emission from agricultural soils.


Assuntos
Esterco , Óxido Nitroso , Agricultura , Animais , Carbono , Carvão Vegetal , Fertilizantes , Óxido Nitroso/análise , Solo
20.
Molecules ; 26(7)2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33918422

RESUMO

The copolymerization of ethylene‒diene conjugates (butadiene (BD), isoprene (IP) and nonconjugates (5-ethylidene-2-norbornene (ENB), vinyl norbornene VNB, 4-vinylcyclohexene (VCH) and 1, 4-hexadiene (HD)), and terpolymerization of ethylene-propylene-diene conjugates (BD, IP) and nonconjugates (ENB, VNB, VCH and HD) using two traditional catalysts of C2-symmetric metallocene-silylene-bridged rac-Me2Si(2-Me-4-Ph-Ind)2ZrCl2 (complex A) and ethylene-bridged rac-Et(Ind)2ZrCl2 (complex B)-with a [Ph3C][B(C6F5)4] borate/TIBA co-catalyst, were intensively studied. Compared to that in the copolymerization of ethylene diene, the catalytic activity was more significant in E/P/diene terpolymerization. We obtained a maximum yield of both metallocene catalysts with conjugated diene between 3.00 × 106 g/molMt·h and 5.00 × 106 g/molMt·h. ENB had the highest deactivation impact on complex A, and HD had the most substantial deactivation effect on complex B. A 1H NMR study suggests that dienes were incorporated into the co/ter polymers' backbone through regioselectivity. ENB and VNB, inserted by the edo double bond, left the ethylidene double bond intact, so VCH had an exo double bond. Complex A's methyl and phenyl groups rendered it structurally stable and exhibited a dihedral angle greater than that of complex B, resulting in 1, 2 isoprene insertion higher than 1, 4 isoprene that is usually incapable of polymerization coordination. High efficiency in terms of co- and ter- monomer incorporation with higher molecular weight was found for complex 1. The rate of incorporation of ethylene and propylene in the terpolymer backbone structure may also be altered by the conjugated and nonconjugated dienes. 13C-NMR, 1H-NMR, and GPC techniques were used to characterize the polymers obtained.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA