271 research outputs found
PhD Conference in Chemical and environmental Enginering
Alternativas de valorización de biomasa algal crecida en plantas de tratamiento de purine
Optimisation of the production of fermentable monosaccharides from algal biomass grown in photobioreactors treating wastewater
Producción CientÃficaBiomass grown in wastewater treatment photobioreactors is a cheap raw material with high contents of carbohydrates, proteins and lipids. This work studies the production of fermentable monosaccharides from three biomasses grown in piggery wastewater (P), domestic wastewater (W) and synthetic medium (S) by applying chemical pretreatment and enzymatic hydrolysis, using a Taguchi design. ANOVA identified temperature, chemical reagent type and chemical reagent concentration as significant operational parameters. However, the biomass concentration, pretreatment time, enzyme dosage and enzymatic hydrolysis time had no remarkable effect. The bacterial content of the biomass had no relevant impact on carbohydrate and protein solubilisation but had a remarkable effect on the degradation of the released carbohydrates (57, 60 and 37% for P, W and S), while also affecting lipid solubilisation. Pretreatment with HCl 2 M at 120 °C resulted the optimal conditions, achieving a monosaccharide recovery of 53, 59 and 80% for P, W and S biomasses, respectively.Gobierno regional de Castilla y León (UIC 071, CLU 2017-09 and VA080G18)Ministerio de Ciencia, Innovación y Universidades (project CTQ2017-84006-C3-1-R)Unión Europea - FEDER (CLU 2017-09 and CTQ2017-84006-C3-1-R
Editorial: Physiology and pathology of neuroglia
Neuroglia is the largest population of cells in the brain and participates in formation, maintenance, and modulation of synaptic circuits. This heterogenous group includes macroglia (astroglia and oligodendroglia) and microglia. Neurons and neuroglia form assemblies that potentiate the cognitive capability of the brain. In this topic, nine articles highlight structural and functional roles of neuroglia in brain physiology, which is fundamental to better understand the biology of neurodevelopmental and neurodegenerative diseases.
Our understanding of brain connectivity evolves rapidly and the cytoarchitecture of underexplored brain regions such as the cerebellum need to be revisited (De Zeeuw et al., 2021). Hence, Gómez-González et al. reviewed the organization of a peculiar cerebellar glial niche located at the subventricular zone of the fourth ventricle. In addition to neurons and ependymal cells, this region is rich in microglia as well as macroglia including astrocytes, Bergmann glia, and oligodendrocyte lineage cells. Further transcriptional and functional heterogeneity within these glial populations is discussed. Despite scarce to non-proliferative activity, this region shares similarity with adult neurogenic niches throughout the brain and various stimulating questions remain to be explored. Furthermore, glial organization is adapted to this highly vascularized niche and contribute to the glioneurovascular unit, a structural and functional element where glial cells respond to stimulation by coupling to increased sensory activity through development (Biesecker et al., 2016; Koehler, 2021). In a perspective contributed by Konecny et al., they hypothesize that augmented neuronal activity is associated with angiogenic factor production and creates an environment of intermittent hypoxia, promoting the expression of hypoxia-inducible transcription factors (HIFs) by the glioneurovascular unit. However, mechanisms triggering glioneurovascular coupling during early sensory neurodevelopment are unknown; therefore, further research using non-invasive approaches is proposed.
Neuron-glia coupling is physiologically tied to volume regulation. Ionic gradients permit neurons to communicate electrically, and glial cells help them to regulate volume. Astrocytes express a variety of cotransport systems and ion channels to maintain brain homeostasis through mobilization of osmolytes (Walch and Fiacco, 2022). Ochoa-de la Paz and Gulias-Cañizo identify glial cells as master regulators of the tripartite synapse volume, a property that gives them an important role in maintaining homeostasis. Dysfunction of volume regulation leads to pathology in conditions such as edema, uremia, and diabetes, in which solute imbalances occur.
Neuron-glia communication is mediated by neurotransmitters including glutamate, the main excitatory neurotransmitter of the brain. This signaling occurs through ionotropic and metabotropic receptors expressed by neurons and glial cells. Particularly, astrocytes modulate neuronal activity through release of gliotransmitters like glutamate and D-serine (Reyes-Haro et al., 2010). Additionally, astrocytes express glutamate transporters to regulate the glutamatergic tone at the synaptic cleft and supply glutamine to neurons that convert it into glutamate or GABA to refill synaptic vesicles (MartÃnez-Lozada and Ortega, 2023). Dysfunction of the glutamate-glutamine shuttle results in excitotoxicity that has been linked to Alzheimer\u27s and Huntington\u27s diseases. Thus, Cuellar-Santoyo et al. summarize the astrocyte\u27s contribution to glutamatergic neurotransmission in physiological and pathological conditions.
Astrocytes also respond to neuronal activity with calcium transients, a signaling mechanism that seems involved in pain and nociception (Prokhorenko and Smyth, 2023). Here, Higinio-RodrÃguez et al. present an experimentally supported perspective in which coherent activity of astrocytes in pain-related brain areas plays critical roles in binding sensory, affective, and cognitive information, on a slow time scale. As astrocytes respond to noxious stimuli via calcium modulation likely independent of neuronal activation, this could represent the mechanism by which pain is created from nociception with the participation of astrocytes.
Glial cell responses in pathology involve inflammasomes, multi-protein intracellular signaling complexes which orchestrate inflammatory responses to a diverse range of pathogens and host-derived signals (Jewell et al., 2022). In their review article, Mata-MartÃnez et al., discuss aspects of the inflammatory process, focusing on accumulating evidence of multiprotein complexes that sense and respond in the context of inflammation. The authors argue that acute and chronic inflammation will engage a coordinated molecular response in various organs, involving glial cells in the brain. Interestingly, Down syndrome (DS) and Alzheimer\u27s disease (AD) are characterized by chronic neuroinflammation, peripheral inflammation, astrogliosis, imbalanced excitatory/inhibitory neuronal function, and cognitive deficits in both humans and mouse models (Ahmed et al., 2022). Little is known about the causes of these pathologies, but patients with DS are suspected to be predisposed to developing AD late in life. GarcÃa and Flores-Aguilar summarize data about glial cells in the context of DS-AD and inflammation.
Links for inflammation and glial cells could also exist in anorexia; food intake is reduced during acute and chronic inflammatory states in human and research models (Gautron and Layé, 2010). Reyes-Haro reviews features of physiological anorexia in research models in comparison with human pathological anorexia, emphasizing valid precautions when extrapolating results. Moreover, he discusses studies in murine models of anorexia in which glial cells putatively play central roles in classical hypothalamic mechanisms, as well as in systemic machineries including the prefrontal cortex. Specifically, the pro-inflammatory environment associated with microglia reactivity, the impact of astrocyte manipulation on food intake associated with purinergic gliotransmission, and the roles of Oligodendrocyte Precursor Cells (OPCs) mediating the anorexigenic action of leptin in mice, are presented.
Another pathology associated with glial cell dysfunction is alcohol exposure during pregnancy. Fetal Alcohol Syndrome (FAS) is a public health problem with a prevalence of 2–5% in the USA. FAS disturbs the structure and function of the brain, but the underlying mechanisms remain elusive (Holloway et al., 2023). Zheng et al., observed loss of the tubulin-binding cofactor B resulting in disorganized microtubules and shortening of astrocytic processes in a model of chronic alcohol exposure. Developmental pathological implications to consider include abnormal migration of neuronal precursors through aberrant radial glial processes and defective synaptic coverage by astrocytes.
Overall, articles in this topic cover diverse aspects of research on glial cells and serve as introductory information to several subfields of glial biology. Ideas presented encourage others to design studies to clarify the roles of physiological and pathological factors with potential use in therapeutic applications and engineering
Study of steam explosion pretreatment and preservation methods of commercial cellulose
Steam explosion (150 – 200 ºC, 5 – 30 min) was performed on a commercial cellulose presented in two configurations (fiberized and compact sheet) and its effect on their chemical and physical properties was studied, along with the influence of two different preservation methods (acetone drying and freezing) after pretreatment. No degradation compounds were produced during pretreatment, although solid recovery (RS) decreased with temperature from 90% to 62%. Similar particle size and surface conditions (increased porosity) were found for both types of pretreated samples despite the extremely different initial configuration. Crystallinity diminished for 150 ºC samples, but 200 ºC pretreatment promoted recrystallization. Pretreatment also reduced polymerization degree, although enzymatic accessibility did not improve. Both acetone and freezing processes extremely affected cellulose properties. Acetone drying counterbalanced crystallinity and enzymatic accessibility variations of pretreated samples, while decreasing polymerization degree to 302. Freezing dramatically decreased enzymatic accessibility of pretreated samples down to 15.8%.UIC-ConsejerÃa de Educación Junta de Castilla y León, University of Valladoli
Ozonolysis: an advantageous pretreatment for lignocellulosic biomass revisited.
Ozonolysis, as a lignocellulosic biomass pretreatment, goes back to 80s; however, in the last years it is becoming widespread again owing to its efficiency and mild operation conditions. Ozone reacts preferably with lignin than carbohydrates, promoting biomass destructuration and delignification, and so the sugar release by enzymatic hydrolysis. The hydrolysate from pretreated biomass has being used as sugars source for second-generation fuels production, mainly ethanol, methane and hydrogen. Short-chain carboxylic acids are the main inhibitory compounds generated, being properly removed by water washing. The most common inhibitory compounds reported for other pretreatments, furfural and HMF (5-hydroxymethylfurfural) , are not found in ozone-pretreated hydrolysates. Composition of pretreated biomass and ozone consumption depends on several process parameters: reactor design, moisture content, particle size, pH, reaction time, ozone/air flow and ozone concentration. Additional studies are necessary to clarify process parameters effec
5ª Jornada de Doctorandos
Valorization of wastewaters via bioenergy and bioproducts using carbohydrates from microalga
Jornada Técnica Agroalimentaria: Alternativas a la Gestión Sostenible de los purines de cerdo.
Alternativas de valorización de biomasa algal procedente del tratamiento de purine
Breakthroughs in bioalcohol production from microalgae: Solving the hurdles
Bioethanol production from microalgae biomass has been proposed as an innovative alternative to substitute fossil fuel sources. Unlike other renewable sources (e.g., lignocellulosic
materials), microalgae biomass has no lignin, which makes the carbohydrate extraction process easier and eventually it should help to develop cleaner and safer bioethanol production processes. Carbohydrates in microalgae can be present in a variety of forms (cellulose, starch, and/or glycogen) and located in different regions of the cells (inner, inside, outside). Carbohydrate type, location, and concentration will strongly depend on cultivation and operation conditions with concentrations ranging from 15% to 50%. Several steps must be applied to obtain bioethanol from this biomass. First, different methods can be employed to disrupt the cell wall and release the carbohydrates such as physical-mechanicals, chemicals, and/or a combination of them. After that, enzymatic hydrolysis could be required to convert the carbohydrates into simple sugars. Finally, a yeast or bacteria fermentation stage is performed to transform these sugars into ethanol. However, it is imperative that the principal parameters of these different steps should be optimized during the bioethanol production before industrial implementation, and more research on economic and life cycle analysis is needed to ensure the economic feasibility of the process.COS
Relaciones recÃprocas en el diseño entre la cerámica de Talavera y las LÃneas de Nazca como elementos de identidad
The histories of Mexico and Peru share great cultural similarities in their representations of the world. Las historias de México y del Perú, comparten grandes similitudes culturales en sus representaciones del mundo. As histórias do México e do Peru compartilham grandes semelhanças culturais em suas representações do mundo. 
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