RESUMEN
BACKGROUND: Takayasu Arteritis (TA) is an immune mediated arteritis causing inflammation of the aorta and its branches, which can result in aortic aneurysms. Our aim is to describe the outcome of surgical management in these patients who presented with Thoracoabdominal aortic aneurysm (TAAA). METHODS: Between 2003 and 2023, 40 TA patients with TAAA underwent operative repair. RESULTS: There were 24 females and 16 males, in the age group of 19-53 years, with hypertension in 20 patients. Raised Erythrocyte sedimentation Rate was present in 13 patients. According to Crawford classification, there were 2 patients with type I, 2 with type II, 17 with type III, 12 patients with type IV and 7 with type V aneurysm. Multiple steno-occlusive lesions of aortic branches were present in 21 patients, with majority affecting the renal artery. Femoral Artery Femoral Vein Partial cardiopulmonary bypass was used for types I, II, III and V. Separate bypass to visceral branches was done in eight patients, of whom five had multiple bypasses and three patients only had renal bypass. Twelve patients underwent reimplantation of branches, out of which nine had multiple vessel reimplantation. Four patients underwent staged repair of the aneurysm, which included visceral debranching in the first day, followed by repair of the aneurysm in the next day. In the immediate postoperative period, ten patients developed acute kidney injury and two required dialysis. Other morbidities included acute respiratory distress syndrome (ARDS), spinal cord dysfunction, bleeding, and wound complications. Three patients expired in the immediate postoperative period. Mean duration of intensive care unit stay was 4.1 days and hospital stay was 12.7 days. Comparison of disease activity with morbidity and mortality was statistically insignificant. Patients were on follow-up for a range of 6 months to 14 years and median follow-up of 25 months. Over this time period four patients expired and four developed anastomotic pseudoaneurysm requiring intervention. On comparing the disease activity at the time of surgery with the long-term arteritis related complications that required intervention, the P value was 0.653 and hence statistically not significant. The 10-year survival rate is 84.4%. CONCLUSIONS: Surgical repair has good and satisfactory outcome, with low early and late mortality rates. Progression of disease can occur at any stage of the disease, hence indicating the need for long term follow-up and frequent imaging.
Asunto(s)
Aneurisma de la Aorta Toracoabdominal , Implantación de Prótesis Vascular , Complicaciones Posoperatorias , Arteritis de Takayasu , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto Joven , Aneurisma de la Aorta Toracoabdominal/cirugía , Implantación de Prótesis Vascular/efectos adversos , Implantación de Prótesis Vascular/mortalidad , Puente Cardiopulmonar , Angiografía por Tomografía Computarizada , Tiempo de Internación , Complicaciones Posoperatorias/etiología , Estudios Retrospectivos , Factores de Riesgo , Arteritis de Takayasu/complicaciones , Arteritis de Takayasu/cirugía , Arteritis de Takayasu/diagnóstico por imagen , Factores de Tiempo , Resultado del TratamientoRESUMEN
Precise identification of correct exon-intron boundaries is a prerequisite to analyze the location and structure of genes. The existing framework for genomic signals, delineating exon and introns in a genomic segment, seems insufficient, predominantly due to poor sequence consensus as well as limitations of training on available experimental data sets. We present here a novel concept for characterizing exon-intron boundaries in genomic segments on the basis of structural and energetic properties. We analyzed boundary junctions on both sides of all the exons (3 28 368) of protein coding genes from human genome (GENCODE database) using 28 structural and three energy parameters. Study of sequence conservation at these sites shows very poor consensus. It is observed that DNA adopts a unique structural and energy state at the boundary junctions. Also, signals are somewhat different for housekeeping and tissue specific genes. Clustering of 31 parameters into four derived vectors gives some additional insights into the physical mechanisms involved in this biological process. Sites of structural and energy signals correlate well to the positions playing important roles in pre-mRNA splicing.
Asunto(s)
Exones , Genoma Humano , Intrones , Genes Esenciales , Genómica , Humanos , Sitios de Empalme de ARNRESUMEN
The present study examined the ability of Quercus castaneifolia C.A.M., Parrotia persica C.A.M., and Carpinus betulus L. for environmental pollution biomonitoring based on the Air Pollution Tolerance Index (APTI). Four leaf traits, total leaf chlorophyll content, leaf extract pH, ascorbic acid content, and relative water content of leaf, were used to compute the APTI values. The study was conducted at five sites in the Hyrcanian forests at different distances from a cement factory close to the Neka city, northern Iran. Based on the results, a 22.5, 30.1, and 25.8% decrease was thus recorded in total chlorophyll content for Q. castaneifolia, P. persica, and C. betulus, respectively, compared to the reference site. However, ascorbic acid content shows an increment of 179.8, 116.8, and 97.3% for P. persica, C. betulus, and Q. castaneifolia, respectively, in the polluted sites as compared to the reference site. The relative water content of P. persica was significantly higher than of Q. castaneifolia and C. betulus in all studied sites. APTI was significantly different among the species, and P. persica was highly tolerant to air pollution, with the highest values of APTI ranging from 11.8 to 16.9. The APTI values of Q. castaneifolia ranged from 9.5 to 11.3 and showed an intermediate tolerance to air pollution. Also, the most sensitive species to air pollution was C. betulus, with a range of 6.6-7.9 in APTI values. Based on APTI values, it can be suggested that P. persica can be used as a biomonitor, while C. betulus can be used as a bioindicator for atmospheric dust deposition and heavy metal pollution.
Asunto(s)
Contaminantes Atmosféricos , Contaminación del Aire , Árboles , Contaminantes Atmosféricos/análisis , Monitoreo Biológico , Plantas , Monitoreo del Ambiente/métodos , Contaminación del Aire/análisis , Clorofila/análisis , Ácido Ascórbico/análisis , Agua/análisis , Hojas de la Planta/químicaRESUMEN
In the current global scenario, the world is under a serious dilemma due to the increasing human population, industrialization, and urbanization. The ever-increasing need for fuels and increasing nutritional problems have made a serious concern on the demand for nutrients and renewable and eco-friendly fuel sources. Currently, the use of fossil fuels is creating ecological and economic problems. Microalgae have been considered as a promising candidate for high-value metabolites and alternative renewable energy sources. Microalgae offer several advantages such as rapid growth rate, efficient land utilization, carbon dioxide sequestration, ability to cultivate in wastewater, and most importantly, they do not participate in the food crop versus energy crop dilemma or debate. An efficient microalgal biorefinery system for the production of lipids and subsequent byproduct for nutraceutical applications could well satisfy the need. But, the current microalgal cultivation systems for the production of lipids and nutraceuticals do not offer techno-economic feasibility together with energy and environmental sustainability. This review article has its main focus on the production of lipids and nutraceuticals from microalgae, covering the current strategies used for lipid production and the major high-value metabolites from microalgae and their nutraceutical importance. This review also provides insights on the future strategies for enhanced microalgal lipid production and subsequent utilization of microalgal biomass.
RESUMEN
PFAs (poly and perfluoroalkyl compounds) are hazardous and bioaccumulative chemicals that do not readily biodegrade or neutralize under normal environmental conditions. They have various industrial, commercial, domestic and defence applications. According to the Organization for Economic Co-operation and Development, there are around 4700 PFAs registered to date. They are present in every stream of life, and they are often emerging and are even difficult to be detected by the standard chemical methods. This review aims to focus on the sources of various PFAs and the toxicities they impose on the environment and especially on humankind. Drinking water, food packaging, industrial areas and commercial household products are the primary PFAs sources. Some of the well-known treatment methods for remediation of PFAs presented in the literature are activated carbon, filtration, reverse osmosis, nano filtration, oxidation processes etc. The crucial stage of handling the PFAs occurs in determining and analysing the type of PFA and its remedy. This paper provides a state-of-the-art review of determination & tools, and techniques for remediation of PFAs in the environment. Improving new treatment methodologies that are economical and sustainable are essential for excluding the PFAs from the environment.
Asunto(s)
Agua Potable , Fluorocarburos , Contaminantes Químicos del Agua , Carbón Orgánico , Agua Potable/análisis , Filtración , Fluorocarburos/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
The aim of the present study was to examine Air Pollution Tolerance Index (APTI) of some climber plant species to develop vertical gardens in Varanasi city which has characteristics of tall building and narrow roads. This condition results in street canyon like structure and hinders the vertical dispersal of air pollutants. We have selected 24 climber plant species which are commonly found in of Varanasi city. Chosen plants can be easily grown either in planter boxes or directly in the ground, with a vertical support they can climb on walls to form green walls or vertical garden. Air Pollution Tolerance Index (APTI) of the selected plant species was calculated and plants with higher APTI are recommended for the development of Vertical garden. Highest APTI was noted for Ipomoea palmata (25.39) followed by Aristolochia elegans (23.28), Thunbergia grandiflora (23.14), Quisqualis indica (22.42), and Clerodendrum splendens (22.36). However, lowest APTI value (8.75) was recorded for the species Hemidesmus indicus. Moreover, the linear regression analysis has revealed a high positive correlation between APTI and ascorbic acid content (R2=0.8837) and positive correlation between APTI and Chlorophyll content (R2=0.6687). On the basis of higher APTI values (greater than 17), nine species of climber plants viz. I. palmata, T. grandiflora, C. splendens, A. elegans, Q. indica, Petria volubilis, Antigonon leptopus, Cryptolepis buchuanni and Tinospora cordifolia have been recommended to develop vertical greenery systems in a compact tropical city.
Asunto(s)
Aclimatación , Contaminación del Aire , Ciudades , Planificación Ambiental , Jardinería , Jardines , Plantas , Contaminantes Atmosféricos , Ácido Ascórbico/análisis , Clorofila/análisis , India , Estrés Fisiológico , Clima TropicalRESUMEN
Conventional machine learning approaches have shown limited predictive power when applied to continuous biohydrogen production due to nonlinearity and instability. This study was aimed at forecasting the dynamic membrane reactor performance in terms of the hydrogen production rate (HPR) and hydrogen yield (HY) using laboratory-based daily operation datapoints for twelve input variables. Hybrid algorithms were developed by integrating particle swarm optimized with functional link artificial neural network (PSO-FLN) which outperformed other hybrid algorithms for both HPR and HY, with determination coefficients (R2) of 0.97 and 0.80 and mean absolute percentage errors of 0.014 % and 0.023 %, respectively. Shapley additive explanations (SHAP) explained the two positive-influencing parameters, OLR_added (1.1-1.3 mol/L/d) and butyric acid (7.5-16.5 g COD/L) supports the highest HPR (40-60 L/L/d). This research indicates that PSO-FLN model are capable of handling complicated datasets with high precision in less computational timeat 9.8 sec for HPR and 10.0 sec for HY prediction.
Asunto(s)
Reactores Biológicos , Hidrógeno , Fermentación , Redes Neurales de la Computación , AlgoritmosRESUMEN
Activated sludge contains a versatile microbiome capable of converting wastes into valuable chemicals like polyhydroxyalkanoates (PHA). This study investigated the influence of repeated feast and famine phases on PHA production as well as the corresponding microbial population dynamics using waste activated sludge (WAS) as inoculum. Hydrolysate derived from rice straw was employed as a substrate for PHA production. The 16sRNA analysis results revealed that Corynebacteriaceae (40%), Bacillaceae (23%), and Pseudomonas (5%) were the primary contributors to PHA synthesis. Notably, Bacillaceae and Pseudomonas thrived in all the feast and famine phases. The achieved PHA concentration was 3.5 ± 0.2 g/L, and its structure and composition were assessed using Fourier Transform Infrared Spectroscopy (FTIR) and Nuclear Magnetic Resonance (NMR). The analysis revealed that the PHA consists of a copolymer of hydroxybutyrate (HB) and hydroxyvalerate (HV), specifically identified as Poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV).
Asunto(s)
Microbiota , Oryza , Polihidroxialcanoatos , Reactores Biológicos , Aguas del AlcantarilladoRESUMEN
Hydrogen can be produced in an environmentally friendly manner through biological processes using a variety of organic waste and biomass as feedstock. However, the complexity of biological processes limits their predictability and reliability, which hinders the scale-up and dissemination. This article reviews contemporary research and perspectives on the application of machine learning in biohydrogen production technology. Several machine learning algorithems have recently been implemented for modeling the nonlinear and complex relationships among operational and performance parameters in biohydrogen production as well as predicting the process performance and microbial population dynamics. Reinforced machine learning methods exhibited precise state prediction and retrieved the underlying kinetics effectively. Machine-learning based prediction was also improved by using microbial sequencing data as input parameters. Further research on machine learning could be instrumental in designing a process control tool to maintain reliable hydrogen production performance and identify connection between the process performance and the microbial population.
Asunto(s)
Hidrógeno , Aprendizaje Automático , Reproducibilidad de los Resultados , Fermentación , BiomasaRESUMEN
The electronic and electrical industrial sector is exponentially growing throughout the globe, and sometimes, these wastes are being disposed of and discarded with a faster rate in comparison to the past era due to technology advancements. As the application of electronic devices is increasing due to the digitalization of the world (IT sector, medical, domestic, etc.), a heap of discarded e-waste is also being generated. Per-capita e-waste generation is very high in developed countries as compared to developing countries. Expansion of the global population and advancement of technologies are mainly responsible to increase the e-waste volume in our surroundings. E-waste is responsible for environmental threats as it may contain dangerous and toxic substances like metals which may have harmful effects on the biodiversity and environment. Furthermore, the life span and types of e-waste determine their harmful effects on nature, and unscientific practices of their disposal may elevate the level of threats as observed in most developing countries like India, Nigeria, Pakistan, and China. In the present review paper, many possible approaches have been discussed for effective e-waste management, such as recycling, recovery of precious metals, adopting the concepts of circular economy, formulating relevant policies, and use of advance computational techniques. On the other hand, it may also provide potential secondary resources valuable/critical materials whose primary sources are at significant supply risk. Furthermore, the use of machine learning approaches can also be useful in the monitoring and treatment/processing of e-wastes. HIGHLIGHTS: In 2019, ~ 53.6 million tons of e-wastes generated worldwide. Discarded e-wastes may be hazardous in nature due to presence of heavy metal compositions. Precious metals like gold, silver, and copper can also be procured from e-wastes. Advance tools like artificial intelligence/machine learning can be useful in the management of e-wastes.
Asunto(s)
Residuos Electrónicos , Metales Pesados , Administración de Residuos , Residuos Electrónicos/análisis , Inteligencia Artificial , Administración de Residuos/métodos , Electrónica , Reciclaje/métodosRESUMEN
Microangiopathic hemolytic anaemia, thrombocytopenia, renal failure, neurologic abnormalities, and fever form the pentad of thrombotic thrombocytopenic purpura (TTP). Early diagnosis is crucial because TTP responds well to plasmapheresis therapy but is associated with substantial mortality if left untreated. A substantial percentage of patients with TTP used to die from systemic microvascular thrombosis in the brain and the heart. However, since plasma exchange therapy became a mainstay in the treatment of TTP, mortality has reduced considerably. Diagnosing TTP can be difficult due to the vast range of symptoms and the absence of clearly defined diagnostic criteria. Hemolytic uremic syndrome and disseminated intravascular coagulation are a close differential of TTP. Here we report two patients with TTP who achieved remission when treated with steroids, plasmapheresis and were free of disease relapse till about two months during follow-up in the outpatient department.
RESUMEN
Polyhydroxybutyrate (PHB) is a natural polyester that may be made by utilizing volatile fatty acids (VFAs) as a substrate. VFA generated by continuous anaerobic fermentation of waste activated sludge (WAS) was fed into bioreactors for PHB synthesis in this work. Series of optimization tests were conducted to increase the biodegradability and hydrolysis of waste activated sludge. It was found out that 0.05 g/g TS of SDBS (sodium dodecylbenzene sulfonate), 70 °C (heat treatment) and 2hr (time) as pretreatment condition would give the highest solubilization. Impact of pH adjustment on the acidogenesis of pretreated WAS was evaluated in batch experiments at varying initial pH (4-10). The result indicated that when operational pH was between 7.5 and 8, the VFA yield was increased by 5.3-18.1%. Continuous acidogenic operation validated the SDBS pretreatment and pH adjustment warranted stable VFA conversion from WAS at a yield of 47% in COD basis. Firmicutes, Actinobacteria and Proteobacteria were affiliated as dominant bacterial phyla in the continuous acidogenesis. The effluent of the continuous acidogenesis was converted to biopolymer with the average yields of 0.23 g PHB-COD/g VFAadded-COD in the feast mode and 0.34 g PHB-COD/g VFAadded-COD in the famine mode. In feast and famine cycle, the average VFA utilization was 55% and 60% respectively. The sequential SDBS pretreatment, acidogenesis and PHB production would produce 162 g of PHB from 1 kg of WAS as COD basis.
Asunto(s)
Ácidos Grasos Volátiles , Aguas del Alcantarillado , Ácidos , Bacterias , Biopolímeros , Reactores Biológicos , Fermentación , Concentración de Iones de Hidrógeno , Compuestos Orgánicos , Aguas del Alcantarillado/microbiologíaRESUMEN
The development of photobioreactor is important for sustainable production of renewable fuels, wastewater treatment and CO2 fixation. For the design and scale-up of a photobioreactor, CFD can be used as an indispensable tool. The present study reviews the recent status of computational flow modelling of various types of photobioreactors, involving fluid dynamics, light transport, and algal growth kinetics. An integrated modelling approach of hydrodynamics, light intensity, mass transfer, and biokinetics in photobioreactor is discussed further. Also, this reviews intensified system to improve the mixing, and light intensity of photobioreactors. Finally, the prospects and challenges of CFD modelling in photobioreactors are discussed. Multi-scale modelling approach and development of low-cost efficient computational framework are the areas to be considered for modelling of photobioreactor in near future. In addition, it is necessary to use process intensification techniques for photobioreactors for improving their hydrodynamics, mixing and mass transfer performances, and algal growth productivity.
Asunto(s)
Microalgas , Fotobiorreactores , Biomasa , Hidrodinámica , CinéticaRESUMEN
Volatile fatty acids (VFAs) are the building blocks of the chemical industry, and they are the primary contributors to the planet's organic carbon cycle. VFA production from fossil fuels (mostly petroleum) is unsustainable, pollutes the environment, and generates greenhouse gases. As a result of these issues, there is a pressing need to develop alternate sources for the long-term generation of VFAs via anaerobic digestion. The accessible feedstocks for its sustainable production, as well as the influencing parameters, are discussed in this review. The use of VFAs as a raw material to make a variety of consumer products is reviewed in order to find a solution. It also bridges the gap between traditional and advanced VFA production and utilization methods from a variety of solid and liquid waste sources for economical stability.
Asunto(s)
Ácidos Grasos Volátiles , Gases de Efecto Invernadero , Anaerobiosis , Reactores Biológicos , Fermentación , Concentración de Iones de HidrógenoRESUMEN
The recent emergence of severe acute respiratory syndrome-Corona Virus 2 (SARS-CoV-2) in late 2019 and its spread worldwide caused an acute pandemic of Coronavirus disease 19 (COVID-19). Since then, COVID-19 has been under intense scrutiny as its outbreak led to significant changes in healthcare, social activities, and economic settings worldwide. Although angiotensin-converting enzyme-2 (ACE-2) receptor is shown to be the primary port of SARS-CoV-2 entry in cells, the mechanisms behind the establishment and pathologies of COVID-19 are poorly understood. As recent studies have shown that host mitochondria play an essential role in virus-mediated innate immune response, pathologies, and infection, in this review, we will discuss in detail the entry and progression of SARS-CoV-2 and how mitochondria could play roles in COVID-19 disease. We will also review the potential interactions between SARS-CoV-2 and mitochondria and discuss possible treatments, including whether mitochondria as a potential therapeutic target in COVID-19. Understanding SARS-CoV-2 and mitochondrial interactions mediated virus establishment, inflammation, and other consequences may provide a unique mechanism and conceptual advancement in finding a novel treatment for COVID-19.
RESUMEN
The presence of heat, methane (CH4) and oxygen in landfill sub-surface causes initiation of spontaneous waste ignition posing severe environmental impacts. A municipal solid waste (MSW) reactor (trough) was designed to monitor landfill gases (LFGs) i.e., CH4 and CO2 and its potential from different waste categories (synthetic waste, fresh waste, 3-month, 6-month, 3-year and 5-year-old waste) collected from open MSW dumpsite. The quantity of cellulose (C), hemicellulose (H) and lignin (L) contents (C + H: L) present in organic waste fraction of each waste category was determined. Results showed that fresh waste which has higher ratio of C + H: L is responsible for maximum CH4 and CO2 generation i.e., 31,660 and 46,078 ml/g of volatile solid, respectively. The ratio of C + H: L observed in fresh waste, 3-month, 6-month, 3-year and 5-year-old waste was 2.62, 1.70, 1.32, 1.21 and 1, respectively. The study also showed that LFG generation is directly proportional to lignocellulose biomass contents present in MSW. Artificial neural network (ANN) modelling was used for the cross validation of CH4 yield (valuable product) which showed ±4% error between experimental and predicted data.
Asunto(s)
Eliminación de Residuos , Residuos Sólidos , Biomasa , Gases/análisis , Lignina , Metano , Residuos Sólidos/análisis , Instalaciones de Eliminación de ResiduosRESUMEN
This review illustrated the role of metal-binding proteins (MBPs) and microbial interaction in assisting the phytoremediation of industrial wastewater polluted with heavy metals. MBPs are used to increase the accumulation and tolerance of metals by microorganisms via binding protein synthesis. Microbes have various protection mechanisms to heavy metals stress like compartmentalization, exclusion, complexity rendering, and the synthesis of binding proteins. MBPs include phytochelatins, metallothioneins, Cd-binding peptides (CdBPs), cysteines (gcgcpcgcg) (CP), and histidines (ghhphg)2 (HP). In comparison with other physico-chemical methods, phytoremediation is an eco-friendly and safe method for the society. The present review concentrated on the efficiency of phytoremediation strategies for the use of MBPs and microbe-assisted approaches.
Asunto(s)
Metales Pesados , Microbiota , Contaminantes del Suelo , Biodegradación Ambiental , Proteínas Portadoras , Metales Pesados/análisis , Plantas/metabolismo , Aguas ResidualesRESUMEN
In this study, the mixture of floral waste and cattle dung in different proportions was utilised to convert into vermicompost using earthworm Eisenia fetida. In the design of the experiment, the optimum amount of floral waste (1325 g) and cattle dung (500 g) was obtained for vermicompost using central composite design (CCD) and compared with the output of artificial neural network (ANN). The optimum proportions of vermicompost showed pH of 7.10, electrical conductivity of 3.39 mS/cm, total organic carbon of 34.01%, C: N ratio of 13, phosphorous of 5.31 g/kg and potassium of 14.45 g/kg. This vermicompost was enriched with sufficient concentration of nutrients like potassium, sodium, phosphorous, and calcium, which are beneficial for the growth of the plants. The current study was based on comparing response surface methodology (RSM) and ANN for maturity parameters and the value of R2 in both the cases was near 1.
Asunto(s)
Estiércol , Oligoquetos , Animales , Bovinos , Redes Neurales de la Computación , Fósforo , SueloRESUMEN
Extracranial carotid artery aneurysms are a rarely reported entity. Here, we describe an unusually large internal carotid artery aneurysm in a 76-year-old female, with progressive enlargement and history of thromboembolic event. She was managed successfully with an open repair and common carotid artery to internal carotid artery bypass.
Asunto(s)
Aneurisma , Enfermedades de las Arterias Carótidas , Tromboembolia , Anciano , Aneurisma/diagnóstico por imagen , Aneurisma/cirugía , Enfermedades de las Arterias Carótidas/diagnóstico por imagen , Enfermedades de las Arterias Carótidas/cirugía , Arteria Carótida Interna/diagnóstico por imagen , Arteria Carótida Interna/cirugía , Femenino , HumanosRESUMEN
An increasing quantum of pollutants from various industrial sector activities represents a severe menace to environmental & ecological balance. Bioremediation is gaining flow globally due to its cost-effective and environment-friendly nature. Understanding biodegradation mechanisms is of high ecological significance. Application of microbial enzymes has been reported as sustainable approach to mitigate the pollution. Immobilized enzyme catalyzed transformations are getting accelerated attention as potential alternatives to physical and chemical methods. The attention is now also focused on developing novel protein engineering strategies and bioreactor design systems to ameliorate overall biocatalysis and waste treatment further. This paper presents and discusses the most advanced and state of the art scientific & technical developments about biocatalytic remediation of industrial pollutants. It also covers various biocatalysts and the associated sustainable technologies to remediate various pollutants from waste streams. Enzyme production and immobilization in bioreactors have also been discussed. This paper also covers challenges and future research directions in this field.