Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 28
Filtrar
1.
Environ Res ; 241: 117348, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-37821064

RESUMO

Attributional life cycle assessment study examines the environmental impact of raw materials, machinery, and unit operations. In the present work, an attributional life cycle assessment (LCA) was employed to assess the environmental and greenhouse gas impacts of a shrimp feed production system. A commercial shrimp feed mill in Tamil Nadu, India, provided inventory data for one-ton shrimp feed (functional unit) for a Cradle-to-Gate evaluation using environmental impact methodologies, specifically Impact 2002+ in SimaPro® (V9.3.0.3) software. The results showed that human health (0.003357 DALY), ecosystem quality (2720.518 PDF × m2 × yr), climate change (2031.696 kg CO2 eq), and resources (71019.42 MJ primary) were the most significantly impacted. The human health category was found to be the most prominent after normalization and weighting (0.47 pt), and strategies were suggested accordingly. The GWP20 and GWP100 measures for long-term climate change were calculated to be 8.7 and 7.33 kg CO2 eq, respectively. Cast iron used in machinery production (GWP 20-15.40%, GWP100-134.5%) and electricity use (GWP 20-6.13%, GWP 100-6.9%) accounted for sizable portions of the burden. Feed production is estimated to contribute 0.2% of global CO2 emissions within the proposed global context. These findings are significant regarding economically and environmentally sustainable shrimp feed production worldwide.


Assuntos
Gases de Efeito Estufa , Humanos , Ecossistema , Dióxido de Carbono/análise , Índia , Meio Ambiente , Aquicultura
2.
Environ Res ; 201: 111550, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34224710

RESUMO

Wastewater management and its treatment have revolutionized the industry sector into many innovative techniques. However, the cost of recycling via chemical treatment has major issues especially in economically poor sectors. On the offset, one of the most viable and economical techniques to clean wastewater is by growing microalgae in it. Since wastewater is rich in nitrates, phosphates and other trace elements, the environment is suitable for the growth of microalgae. On the other side, the cost of harvesting microalgae for its secondary metabolites is burgeoning. While simultaneously growing of microalgae in photobioreactors requires regular feeding of the nutrients and maintenance which increases the cost of operation and hence cost of its end products. The growth of microalgae in waste waters makes the process not only economical but they also manufacture more amounts of value added products. However, harvesting of these values added products is still a cumbersome task. On the offset, it has been observed that pretreating the microalgal biomass with ultrasonication allows easy oozing of the secondary metabolites like oil, proteins, carbohydrates and methane at much lower cost than that required for their extraction. Among microalgae diatoms are more robust and have immense crude oil and are rich in various value added products. However, due to their thick silica walls they do not ooze the metabolites until the mechanical force on their walls reaches certain threshold energy. In this review recycling of wastewater using microalgae and its pretreatment via ultrasonication with special reference to diatoms is critically discussed. Perspectives on circular bioeconomy and knowledge gaps for employing microalgae to recycle wastewater have been comprehensively narrated.


Assuntos
Diatomáceas , Microalgas , Agricultura , Águas Residuárias
3.
J Environ Manage ; 227: 216-228, 2018 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-30195147

RESUMO

Design of experiment and artificial neural networks (ANN) have been effectively employed to predict the rate of uptake of Zn(II) ions onto defatted pongamia oil cake. Four independent variables such as, pH (2.0-7.0), initial concentration of Zn(II) ions (50-500 mg/L), temperature (30ºC-50 °C), and dosage of biosorbent (1.0-5.0 g/L) were used for the batch mode while the three independent variables viz. flowrate, initial concentration of Zn(II) ions and bed height were employed for the continuous mode. Second-order polynomial equations were then derived to predict the Zn(II) ion uptake rate. The optimum conditions for batch studies was found to be pH: 4.45, metal ion concentration: 462.48 mg/L, dosage: 2.88 g/L, temperature: 303 K and on the other hand the column studies flow rate: 5.59 mL/min, metal ion concentration: 499.3 mg/L and bed height: 14.82 cm. Under these optimal condition, the adsorption capacity was 80.66 mg/g and 66.29 mg/g for batch and column studies, respectively. The same data was fed to train a feed-forward multilayered perceptron, using MATLAB to develop the ANN based model. The predictive capabilities of the two methodologies were compared, by means of the absolute average deviation (AAD) (4.57%), model predictive error (MPE) (4.15%), root mean square error (RMSE) (3.19), standard error of prediction (SEP) (4.23) and correlation coefficient (R) (0.99) for ANN and for RSM AAD (16.27%), MPE (21,25%), RMSE (13.15%), SEP and R (0.96) by validation data. The findings suggested that compared to the prediction ability of RSM model, the properly trained ANN model has better prediction ability. In batch studies, equilibrium data was used to determine the isotherm constants and first and second order rate constants. In column, bed depth service time (BDST) and Thomas model was used to fit the obtained column data.


Assuntos
Pongamia , Poluentes Químicos da Água , Zinco/química , Adsorção , Concentração de Íons de Hidrogênio , Íons , Cinética , Millettia , Redes Neurais de Computação , Zinco/isolamento & purificação
4.
Bioprocess Biosyst Eng ; 38(2): 389-97, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25194465

RESUMO

More than half of the bioethanol plants in operation today use corn or grains as raw materials. The downstream processing of mash after fermentation to produce ethanol and distiller grains is an energy-demanding process, which needs retrofitting for optimization. In addition, the fluctuation in the ethanol and grain prices affects the overall profitability of the plant. For this purpose, a process simulation was performed in Aspen Plus(®) based on an existing industrial plant located in Sweden. The simulations were compared using different scenarios including different concentrations of ethanol, using the stillage for biogas production to produce steam instead of distiller grains as a by-product, and altering the purity of the ethanol produced. Using stillage for biogas production, as well as utilizing the steam, reduced the overall energy consumption by 40% compared to the plant in operation. The fluctuations in grain prices had a high impact on the net present value (NPV), where grain prices greater than 349 USD/ton reached a zero NPV. After 20 years, the plant in operation producing 41,600 tons ethanol/year can generate a profit of 78 million USD. Compared to the base case, the less purified ethanol resulted in a lower NPV of 30 million USD.


Assuntos
Reatores Biológicos/economia , Reatores Biológicos/microbiologia , Grão Comestível/microbiologia , Etanol/economia , Etanol/metabolismo , Modelos Econômicos , Simulação por Computador , Modelos Biológicos , Avaliação de Processos em Cuidados de Saúde , Estados Unidos
5.
Cureus ; 16(3): e55396, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38562312

RESUMO

Background Ixora species are perennial shrubs and flowering plants belonging to the family Rubiaceae. The leaf and flower parts of Ixora coccinea (I. coccinea) andIxora alba (I. alba) were aimed at isolating their active fractions. The present study was to determine in vitro antitumor activity against malignant melanoma cell lines for phytosome formulation. Materials and methods Two species, I. coccinea (red flowers and leaves) and I. alba (white flowers and leaves), were selected, and this study focused on determining the active fraction by comparing the in vitro antimicrobial and antioxidant potentials of petroleum ether, chloroform, ethyl acetate, and hydroalcoholic (ethanol:water, 70:30 v/v) extracts. The identified potent extract was subjected to in vitro anticancer activity in malignant melanoma cell lines. Results A phytochemical study revealed phytosterols, flavonoids, proteins, amino acids, alkaloids, carbohydrates, phenols, tannins, and diterpenes. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay was used to evaluate the antioxidant effect of I. coccinea and I. alba leaf and flower extracts. In the DPPH assay, I. coccinea flower hydroalcoholic extract (ICFHA) had an IC50 value of 248.99 µg/mL, and I. coccinea leaf hydroalcoholic extract (ICLHA) had an IC50 value of 268.87 µg/mL. These two extracts had a lower value with a higher antioxidant effect. In the total antioxidant assay, I. coccinea leaf ethyl acetate extract (ICLEA) and I. coccinea leaf chloroform extract (ICLCE) have 77.4 ± 0.05 and 68.9 ± 0.03 mg of ascorbic acid equivalent per gm of extract, respectively. These two extracts exhibited a high antioxidant effect. The antimicrobial potential was evaluated using selected bacterial and fungal strains using the agar-well diffusion method. Petroleum ether and chloroform extracts of I. coccinea and I. alba leaves and flowers did not possess antimicrobial activity with any of the bacterial or fungal strains. An ethyl acetate extract and a hydroalcoholic extract of I. coccinea leaves and flowers showed antimicrobial activity against Enterococcus faecalis, Candida albicans, and Staphylococcus aureus. An ethyl acetate extract of I. coccinea flower and a hydroalcoholic extract of I. alba leaf showed a significant zone of inhibition when compared with standard chloramphenicol for all three selected strains, which may be due to the presence of active phytoconstituents. ICLHA showed a MIC of ≤300 µg/mL for Enterococcus faecalis and Staphylococcus aureus and ≤400 µg/mL for Candida albicans microbial strains. The high total flavonoid content was reported in ICLEA at 771.31 µg/mL and in I. coccinea flower ethyl acetate extract (ICFEA) at 694.69 µg/mL. High-performance thin layer chromatography (HPTLC) analysis showed a high quercetin (QCE) content in the ICLEA extract. To prove the in vitro skin anticancer activity, an MTT assay was performed for the ICLEA extract in a malignant melanoma cell line, and the IC50 value was reported as 7.96 µg/mL. Conclusion I. coccinea leaf ethyl acetate extract revealed a significant total flavonoid content in analysis through the aluminum chloride method, and the presence of a high QCE content was confirmed by HPTLC analysis. The in vitro skin anticancer activity of ICLEA was confirmed by the MTT assay; therefore, it was concluded that the ICLEA extract was a potent fraction and was selected to develop a phytosome.

6.
Bioresour Technol ; 400: 130665, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38582235

RESUMO

Biogas production through anaerobic digestion (AD) is one of the complex non-linear biological processes, wherein understanding its dynamics plays a crucial role towards process control and optimization. In this work, a machine learning based biogas predictive model was developed for high solid systems using algorithms, including SVM, ET, DT, GPR, and KNN and two different datasets (Dataset-1:10, Dataset-2:5 inputs). Support Vector Machine had the highest accuracy (R2) of all the algorithms at 91 % (Dataset-1) and 87 % (Dataset-2), respectively. The statistical analysis showed that there was no significant difference (p = 0.377) across the datasets, wherein with less inputs, accurate results could be predicted. In case of biogas yield, the critical factors which affect the model predictions include loading rate and retention time. The developed high solid machine learning model shows the possibility of integrating Artificial Intelligence to optimize and control AD process, thus contributing to a generic model for enhancing the overall performance of the biogas plant.


Assuntos
Biocombustíveis , Aprendizado de Máquina , Anaerobiose , Máquina de Vetores de Suporte , Algoritmos , Reatores Biológicos
7.
Cureus ; 16(4): e58958, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38800336

RESUMO

Background Ixora coccinea is a medicinal plant with many active constituents that are responsible for wound healing and have anticancer properties. Herbal extracts increase the mechanisms related to wound healing, like blood clotting, fighting infection, and epithelialization. The effect responsible for this property may be the presence of phytoconstituents like flavonoids, polyphenols, and alkaloids. Many researchers have evaluated the wound-healing effect of I. coccinea leaf extract in aqueous methanol. This study aimed to determine the in vitro wound healing and anticancer efficacy of I. coccinea leaf ethyl acetate extract and evaluate the in silico docking of the selected phytoconstituents of I. coccinea in the 2vcj protein. Materials and methods The human dermal fibroblast cell line was used to determine the rates of cell migration and proliferation for evaluating the wound-healing effect of the I. coccinea leaf ethyl acetate fraction. 4',6-diamidino-2-phenylindole (DAPI) fluorescence labeling was used to estimate the rate of cell migration. The one-step TUNEL (TdT-mediated dUTP Nick-End Labeling) in situ apoptosis kit and the annexin V-FITC/7-AAD apoptosis kit were used to perform DNA damage assays in the malignant melanoma cell line. The ethyl acetate fraction of I. coccinea leaves was analyzed for its impact on wound healing markers, including keratin-10, keratin-14, type IV collagen, and α-SMA. Results The wound-healing nature was interesting in the ethyl acetate fraction at doses of 50 µg/mL and 100 µg/mL. Both studies involved in the DNA damage study against malignant melanoma cell lines showed the cleavage of apoptotic cancer cells, which was detected using a fluorescence microscope. When compared with the control, a dose of 100 µg/ml of ethyl acetate fraction from the leaves of I. coccinea showed fibroblast migration of cells into the wound area. The statistical values were considered significant at the level of P < 0.05. An in silico docking study on the 2vcj protein revealed that selected phytoconstituents of I. coccinea resulted in good docking scores to inhibit Hsp90. Conclusion I. coccinea ethyl acetate leaf extract can inhibit the growth of malignant melanoma cell lines and promote wound healing, as shown by the study results. It might be a viable therapeutic modality for skin cancer.

8.
Sci Total Environ ; 914: 169857, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38190912

RESUMO

Flue gases are the gases which are produced from industries related to chemical manufacturing, petrol refineries, power plants and ore processing plants. Along with other pollutants, sulfur present in the flue gas is detrimental to the environment. Therefore, environmentalists are concerned about its removal and recovery of resources from flue gases due to its activation ability in the atmosphere to transform into toxic substances. This review is aimed at a critical assessment of the techniques developed for resource recovery from flue gases. The manuscript discusses various bioreactors used in resource recovery such as hollow fibre membrane reactor, rotating biological contractor, sequential batch reactor, fluidized bed reactor, entrapped cell bioreactor and hybrid reactors. In conclusion, this manuscript provides a comprehensive analysis of the potential of thermotolerant and thermophilic microbes in sulfur removal. Additionally, it evaluates the efficacy of a multi-enzyme engineered bioreactor in this process. Furthermore, the study introduces a groundbreaking sustainable model for elemental sulfur recovery, offering promising prospects for environmentally-friendly and economically viable sulfur removal techniques in various industrial applications.


Assuntos
Poluentes Atmosféricos , Poluentes Ambientais , Gases/química , Enxofre/química , Reatores Biológicos
9.
Bioresour Technol ; 381: 129161, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37172745

RESUMO

In this study, a mild two-stage hydrothermal pretreatment was employed to optimally valorize industrial hemp (Cannabis sativa sp.) fibrous waste into sugars for Poly(3-hydroxybuyrate) (PHB) production using recombinant Escherichia coli LSBJ. Biomass was pretreated using hot water at 160, 180, and 200 °C for 5 and 10 min (15% solids), followed by disk refining. The sugar yields during enzymatic hydrolysis were found to improve with increasing temperature and the yields for hot water-disk refining pretreatment (HWDM) were higher compared to only hot water pretreatment at all conditions. The maximum glucose (56 g/L) and cellulose conversion (92%) were achieved for HWDM at 200 °C for 10 min. The hydrolysate obtained was fermented at a sugar concentration of 20 g/L. The PHB inclusion and concentration of 48% and 1.8 g/L, respectively, were similar to those from pure sugars. A pH-controlled fermentation resulted in a near bi-fold increase in PHB yield (3.46 g/L).


Assuntos
Cannabis , Resíduos Industriais , Carboidratos , Fermentação , Açúcares , Água , Hidrólise
10.
Sci Total Environ ; 883: 163656, 2023 Jul 20.
Artigo em Inglês | MEDLINE | ID: mdl-37088382

RESUMO

Carbon capture storage and utilization (CCSU) has the potential to become a key tool to mitigate climate change, thus, aiding in achieving the objectives of the 2015 Paris Agreement. Even though the relevant remediation technology has achieved technical maturity to a certain extent, implementation of CCSU on a larger scale is currently limited because of non-technical parameters that include cost, legalization, lack of storage reservoir, and market mechanism to penalize CO2 emitter. Among these, cost emerges as the primary barrier to the dissemination of CCSU. Hence, necessary policy frameworks and incentives must be provided by governing agencies to enable faster dissemination of carbon capture and utilization (CCU) and carbon capture and storage (CCS) globally. Meanwhile, strict implementation of a carbon tax across nations and market demand for products generated using captured CO2 can aid in the fast adoption of CCU and CCS. This review assessed the economic feasibility and sustainability of CCS and CCU technologies to identify the barriers to commercializing these technologies.

11.
Bioresour Technol ; 384: 129250, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37286046

RESUMO

Due to resource scarcity, current industrial systems are switching from waste treatment, such as wastewater treatment and biomass, to resource recovery (RR). Biofuels, manure, pesticides, organic acids, and other bioproducts with a great market value can be produced from wastewater and activated sludge (AS). This will not only help in the transition from a linear economy to a circular economy, but also contribute to sustainable development. However, the cost of recovering resources from wastewater and AS to produce value-added products is quite high as compared to conventional treatment methods. In addition, most antioxidant technologies remain at the laboratory scale that have not yet reached the level at industrial scale. In order to promote the innovation of resource recovery technology, the various methods of treating wastewater and AS to produce biofuels, nutrients and energy are reviewed, including biochemistry, thermochemistry and chemical stabilization. The limitations of wastewater and AS treatment methods are prospected from biochemical characteristics, economic and environmental factors. The biofuels derived from third generation feedstocks, such as wastewater are more sustainable. Microalgal biomass are being used to produce biodiesel, bioethanol, biohydrogen, biogas, biooils, bioplastics, biofertilizers, biochar and biopesticides. New technologies and policies can promote a circular economy based on biological materials.


Assuntos
Microalgas , Águas Residuárias , Esgotos , Biocombustíveis , Biomassa
12.
Bioresour Technol ; 376: 128903, 2023 May.
Artigo em Inglês | MEDLINE | ID: mdl-36931447

RESUMO

Environmental contamination is considered a major issue with the growing urbanization and industrialization. In this context, the scientific society is engaged in searching for a sustainable, safe, and eco-friendly solution. Sustainable materials such as biochar play an important role in environmental contamination. It has some specific properties such as micropores which increase the surface area to bind the pollutants. This review endeavors to analyze the potential of fruit wastes especially tropical fruit tree residues as potential candidates for producing highly efficient biochar materials. The review discusses various aspects of biochar production viz. pyrolysis, torrefaction, hydrothermal carbonization, and gasification. In addition, it discusses biochar use as an adsorbent, wastewater treatment, catalyst, energy storage, carbon sequestration and animal feed. The review put forward a critical discussion about key aspects of applying biochar to the environment.


Assuntos
Frutas , Árvores , Animais , Carvão Vegetal/química , Solo/química
13.
Bioresour Technol ; 351: 126970, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35276373

RESUMO

Time series-based modeling provides a fundamental understanding of process fluctuations in an anaerobic digestion process. However, such models are scarce in literature. In this work, a dynamic model was developed based on modified Hill's model using MATLAB, which can predict biomethane production with time series. This model can predict the biomethane production for both batch and continuous process, across substrates and at diverse conditions such as total solids, loading rate, and days of operation. The deviation between literature and the developed model was less than ± 7.6%, which shows the accuracy and robustness of this model. Moreover, statistical analysis showed there was no significant difference between literature and simulation, verifying the null hypothesis. Finding a steady and optimized loading rate was necessary to an industrial perspective, which usually requires extensive experimental data. With the developed model, a stable and optimal methane yield generating loading rate could be identified at minimal input.


Assuntos
Reatores Biológicos , Metano , Anaerobiose , Biocombustíveis , Simulação por Computador
14.
Chemosphere ; 291(Pt 1): 132753, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34780737

RESUMO

Wastewater (WW) contains nitrogen (N) and phosphorus (P), where N oxidizes to nitrate followed by denitrification to release N2 and P is accumulated in sludge. Higher concentrations of N and P leads to eutrophication and algal blooming, thereby threatening the aquatic life systems. Such nutrients could be potentially recovered avoiding the fertilizer requirements. Distinct nutrient recovery systems have been demonstrated including chemical precipitation, ion-exchange, adsorption, bio-electrochemical systems, and biological assimilation at various scales of volumes. This study focusses on the nutrient recovery possibility from wastewater in India. The resource estimation analysis indicates that at 80% recovery, 1 million liters per day (MLD) of sewage can generate 17.3-kg of struvite using chemical precipitation. When compared with traditional fertilizers, nutrient recovery from sewage has the potential to avoid 0.38-Mt/a in imports. Replacing conventional fertilizer with struvite recovered from WW avoids 663.2 kg CO2eq/ha in emissions (53%). Prevailing WW treatment looks at maintaining the discharging standards while recovering nutrients is an advanced option for a self-reliant and sustainable circular economy. However, more detailed assessments are necessary from techno-economic and environmental perspective in realizing these technologies at an industrial scale.


Assuntos
Eliminação de Resíduos Líquidos , Águas Residuárias , Nutrientes , Fósforo , Esgotos , Estruvita
15.
Bioresour Technol ; 360: 127565, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35788392

RESUMO

This review provides an update on the state-of-the art technologies for the valorization of solid waste and its mechanism to generate various bio-products. The organic content of these wastes can be easily utilized by the microbes and produce value-added compounds. Microbial fermentation techniques can be utilized for developing waste biorefinery processes. The utilization of lignocellulosic and plastics wastes for the generation of carbon sources for microbial utilization after pre-processing steps will make the process a multi-product biorefinery. The C1 and C2 gases generated from different industries could also be utilized by various microbes, and this will help to control global warming. The review seeks to expand expertise about the potential application through several perspectives, factors influencing remediation, issues, and prospects.


Assuntos
Biocombustíveis , Resíduos Sólidos , Biocombustíveis/análise , Fermentação
16.
Chemosphere ; 288(Pt 2): 132589, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34678344

RESUMO

Photosynthetic microbial fuel cells (PMFCs) with microalgae have huge potential for treating wastewater while simultaneously converting light energy into electrical energy. The efficiency of such cells directly depends on algal growth, which depends on light intensity. Higher light intensity results in increased potential as well as enhancement in generation of biomass rich in biopolymers. Such biopolymers are produced either by microbes at anode and algae at cathode or vice versa. The biopolymers recovered from these biological sources can be added in wastewater alone or in combination with nanomaterials to act as nanoadsorbents. These nanoadsorbents further increase the efficiency of PMFC by removing the pollutants like metals and dyes. In this review firstly the effect of different light intensities on the growth of microalgae, importance of diatoms in a PMFC and their impact on PMFCs efficiencies have been narrated. Secondly recovery of biopolymers from different biological sources and their role in removal of metals, dyes along with their impact on circular bioeconomy have been discussed. Thereafter bottlenecks and future perspectives in this field of research have been narrated.


Assuntos
Fontes de Energia Bioelétrica , Poluentes Ambientais , Microalgas , Biomassa , Biopolímeros
17.
Bioresour Technol ; 360: 127592, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35809874

RESUMO

Increases in population and urbanization leads to generation of a large amount of food waste (FW) and its effective waste management is a major concern. But putrescible nature and high moisture content is a major limiting factor for cost effective FW valorization. Bioconversion of FW for the production of value added products is an eco-friendly and economically viable strategy for addressing these issues. Targeting on production of multiple products will solve these issues to greater extent. This article provides an overview of bioconversion of FW to different value added products.


Assuntos
Eliminação de Resíduos , Gerenciamento de Resíduos , Alimentos
18.
Bioanalysis ; 13(16): 1259-1273, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34463119

RESUMO

Aim: Clinical monitoring of oxcarbazepine (OXC) and its metabolite licarbazepine (MHD) in biological matrix requires a sensitive and validated analytical method. The aim of this study is to develop and validate an optimized ultra performance liquid chromatography-MS/MS based bioanalytical method for the simultaneous estimation of OXC and its metabolite MHD in human plasma, using deuterated internal standard method. Materials & methods: A reverse phase ultra performance liquid chromatography analysis and mass spectrometric detection was performed using electrospray ionization in positive ion mode as interface, multiple reaction monitoring as mode of acquisition. Results & conclusion: The linearity range was 10-4011 ng/ml for OXC and 40-16061 ng/ml for MHD. The kinetic parameters were calculated and compared for bioequivalence. This method fulfilled the validation guidelines, could be employed for determining bioavailability and in new formulation development studies.


Assuntos
Anticonvulsivantes/sangue , Epilepsia/tratamento farmacológico , Oxcarbazepina/sangue , Plasma/metabolismo , Cromatografia Líquida/métodos , Humanos , Espectrometria de Massas em Tandem/métodos
19.
Cureus ; 13(1): e12762, 2021 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-33489639

RESUMO

Introduction and aims Assessment of chest radiographs is a fundamental clinical skill, often taught opportunistically. Medical students are taught how to read adult chest radiographs, however, in our experience, there is often a lack of structured training for the interpretation of pediatric chest radiographs. Our aim was to develop and evaluate an online approach for medical students to learn this skill.  Materials and methods Ericsson's expertise acquisition theory was used to develop 10 sets of 10 practice radiographs which were graded using the X-ray difficulty score. Medical student volunteers (from Keele University School of Medicine) were recruited in the paediatric rotation of their first clinical year. Pre- and post-training tests of identical difficulty were offered. A semistructured focus group was conducted after the tests, the transcription of which was analyzed using grounded theory. Results Of 117 students in the year, 54 (46%) originally volunteered. The engagement was initially high but fell during the year, particularly during the pre-examination block. The high drop-out rate made the quantitative measurement of effectiveness difficult. The focus group suggested that pressure of other work, exam preparation, technical factors, and inflexibility of the study protocol reduced engagement. Conclusions Although the topic covered was seen as important and relevant to exams, the current system requires development to make it more effective and engaging.

20.
Sci Total Environ ; 765: 144429, 2021 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-33385808

RESUMO

Biohydrogen is a clean and renewable source of energy. It can be produced by using technologies such as thermochemical, electrolysis, photoelectrochemical and biological, etc. Among these technologies, the biological method (dark fermentation) is considered more sustainable and ecofriendly. Dark fermentation involves anaerobic microbes which degrade carbohydrate rich substrate and produce hydrogen. Lignocellulosic biomass is an abundantly available raw material and can be utilized as an economic and renewable substrate for biohydrogen production. Although there are many hurdles, continuous advancements in lignocellulosic biomass pretreatment technology, microbial fermentation (mixed substrate and co-culture fermentation), the involvement of molecular biology techniques, and understanding of various factors (pH, T, addition of nanomaterials) effect on biohydrogen productivity and yield render this technology efficient and capable to meet future energy demands. Further integration of biohydrogen production technology with other products such as bio-alcohol, volatile fatty acids (VFAs), and methane have the potential to improve the efficiency and economics of the overall process. In this article, various methods used for lignocellulosic biomass pretreatment, technologies in trends to produce and improve biohydrogen production, a coproduction of other energy resources, and techno-economic analysis of biohydrogen production from lignocellulosic biomass are reviewed.


Assuntos
Hidrogênio , Tecnologia , Biocombustíveis , Biomassa , Características da Família , Fermentação , Hidrogênio/análise , Lignina
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA