Unveiling potential of promising filamentous microalga Klebsormidium cf. nitens: Shear stress resilience and carotenoid-fatty acid dynamics in tubular photobioreactor.

In this study, the effects of shear stress and different culture media on the growth of the filamentous microalga Klebsormidium cf. nitens were studied. The microalga's growth, carotenoids and fatty acids were further evaluated in a pump-driven tubular photobioreactor. The results show that this microalga had the ability to withstand high shear stress and the adaptability to grow in a culture medium that lacks certain trace elements. K. cf. nitens grew consistently in the tubular photobioreactor at different average light intensities although it did not grow well in a tall bubble column. The carotenoid analysis revealed that the xanthophyll cycle was activated to protect the cell photosynthetic system. The fatty acids increased with irradiance, with linoleic acid (C18:2n6) making up over 50 % of the total fatty acids. This study supports the potential of employing pump-driven tubular photobioreactors to produce the filamentous microalga K. cf nitens at the large scale.

Formation of intraneuronal iron deposits following local release from nanostructured silica injected into rat brain parenchyma.

Nanostructured materials with controllable properties have been used to cage and release various types of compounds. In the present study, iron-loaded nanostructured sol-gel SiO2-Fe materials were prepared and injected into the rat brain to develop a method for gradual iron delivery into the neurons with the aims to avoid acute iron toxicity and develop an animal model of gradual, metal-induced neurodegeneration. Nanoparticles were prepared by the traditional method of hydrolysis and condensation reactions of tetraethyl orthosilicate at room temperature and subsequent heat treatment at 200 °C. FeSO4 was added in situ during the silica preparation. The resulting materials were characterized by UV-VIS and infrared spectroscopies, X-ray diffraction, and N2 adsorption-desorption. An in vitro ferrous sulfate release test was carried out in artificial cerebrospinal fluid as the release medium showing successful ferrous sulfate loading on nanostructured silica and sustained iron release during the test time of 10 h. Male Wistar rats administered with SiO2-Fe nanoparticles in the substantia nigra pars compacta (SNpc) showed significant intraneuronal increase of iron, in contrast to the animals administered with FeSO4 that showed severe neuronal loss, 72 h post-treatment. Both treatments induced lipid fluorescent product formation in the ventral midbrain, in contrast to iron-free SiO2 and PBS-only injection controls. Circling behavior was evaluated six days after the intranigral microinjection, considered as a behavioral end-point of brain damage. The apomorphine-induced ipsilateral turns in the treated animals presented significant differences in relation to the control groups, with FeSO4 administration leading to a dramatic phenotype, compared to a milder impact in SiO2-Fe administrated animals. Thus, the use of SiO2-Fe nanoparticles represents a slow iron release system useful to model the gradual iron-accumulation process observed in the SNpc of patients with idiopathic Parkinson's disease.

Removal of phenolic inhibitors from lignocellulose hydrolysates using laccases for the production of fuels and chemicals.

Lignocellulose is the most abundant biopolymer in the biosphere. It is inexpensive and therefore considered an attractive feedstock to produce biofuels and other biochemicals. Thermochemical and/or enzymatic pretreatment is used to release fermentable monomeric sugars. However, a variety of inhibitory by-products such as weak acids, furans, and phenolics that inhibit cell growth and fermentation are also released. Phenolic compounds are among the most toxic components in lignocellulosic hydrolysates and slurries derived from lignin decomposition, affecting overall fermentation processes and production yields and productivity. Ligninolytic enzymes have been shown to lower inhibitor concentrations in these hydrolysates, thereby enhancing their fermentability into valuable products. Among them, laccases, which are capable of oxidizing lignin and a variety of phenolic compounds in an environmentally benign manner, have been used for biomass delignification and detoxification of lignocellulose hydrolysates with promising results. This review discusses the state of the art of different enzymatic approaches to hydrolysate detoxification. In particular, laccases are used in separate or in situ detoxification steps, namely in free enzyme processes or immobilized by cell surface display technology to improve the efficiency of the fermentative process and consequently the production of second-generation biofuels and bio-based chemicals.

Sustainable use of wastes as reactive material in permeable reactive barrier for remediation of acid mine drainage: Batch and continuous studies.

The aim of this work was to evaluate the feasibility of the use of different industrial and agricultural wastes as reactive materials in Permeable Reactive Barriers (PRB) for Acid Mine Drainage (AMD) remediation. Sugar foam (SF), paper mill sludge (PMS), drinking water sludge (DWS) and olive mill waste (OMW) were evaluated in terms of pH neutralization and metal removal from AMD. Laboratory batch tests and continuous pilot scale up-flow columns containing 82% of Volcanic Slag (VS), as porous fill material, and 18% w/w of one of the industrial and agricultural wastes previously indicated, were tested. From the batch tests it was observed that the reactive material presenting the best results were the SF and the PMS. The results obtained in all the PRB were accurately described by a pseudo-first order model, presenting coefficient of determination higher than 0.96 in all the cases. During the continuous operation of the PRB, the porosity and hydraulic retention time (HRT) of most of the up-flow columns strongly decreased due to chemical precipitation and biofilm growth. The SF presented a significant number of fine particles that were washed out by the liquid flow, generating an effluent with very high total suspended solid concentration. Despite SF was the material with the highest alkalinity potential, the reduction of the HRT limited its neutralization and metal removal capacity. PMS and DWS presented the best pollutant removal yields in the continuous operation of the PRB, ranging from 55 to 99% and 55-95% (except in the case of the Mn), respectively. These results allowed the metal removal from the AMD. Additionally, these wastes presented very good biological sulphate reduction. Based on these results, the use of PMS and DWS as reactive material in PRB would allow to simultaneously valorise the industrial waste, which is very interesting within the circular economy framework, and to remove metals from the AMD by means of a low-cost and environmentally sustainable procedure.

Acrylamide bioaccessibility in potato and veggie chips. Impact of in vitro colonic fermentation on the non-bioaccessible fraction.

Potato-based products contribute largely to the daily intake of acrylamide. In addition to potato crisps, the European Commission has included veggie crisps in the list of foods that should be monitored for their acrylamide content. In the present study, acrylamide content in potato and veggie chips (sweet potato, beetroot and carrot) and their bioaccessibility after in vitro digestion was assessed. The non-bioaccessible fraction was also submitted to in vitro fermentation under colonic conditions. Faecal samples from volunteers of three age groups (children, adolescents and adults) were used to evaluate the microbiota effect on the acrylamide availability. Sweet potato chips exhibited the highest acrylamide content (2342 µg/kg), followed by carrot (1279 µg/kg), beetroot (947 µg/kg) and potato chips (524 µg/kg). After in vitro digestion, acrylamide bioaccessibility was significantly lower in veggie chips (59.7-60.4 %) than in potato chips (71.7 %). Potato and sweet potato chips showed the significantly lowest acrylamide content in the non-bioaccessible fraction (22.8 and 24.1 %, respectively) as compared with beetroot chips (28.4 %). After the fermentation step, acrylamide percentage in the soluble fraction of veggie chips ranged from 43.03 to 71.89 %, the highest values being observed in sweet potato chips fermented with microbiota from children. This fact would involve that the acrylamide was released from the non-bioaccessible fractions by the microbiota. These findings point out that the levels of potentially absorbable acrylamide after the complete gastrointestinal process could be modulated by both the food matrix composition and the microbiota. These factors should be further considered for a more precise risk assessment of dietary acrylamide in humans.

Assessment of the acrylamide bioaccessibility in cereal and potato-based foods after in vitro digestion.

Acrylamide bioaccessibility during and after in vitro gastrointestinal digestion of cereal and potato-based foods was monitored. Isolated vs combined meals were evaluated with the aim of investigating acrylamide-food matrix interactions. The meals considered were breakfast cereals, biscuits, patatas a lo pobre (patatas-pobre) and French fries for isolated foods; breakfast cereals with yoghurt, biscuits with milk, patatas-pobre with scrambled eggs and French fries with meat steak for combined foods. The non-bioaccessible fraction of acrylamide tended to decrease during the digestion process in all the systems. However, the final bioaccessible acrylamide was affected by the food matrix composition (fibre, protein, sugars and lipids). The digestion of breakfast cereals, biscuits with milk, patatas-pobre and patatas-pobre with scrambled eggs led to acrylamide bioaccessibility below the initial content of the contaminant in the meals. In absolute values, the combined consumption of biscuits and milk significantly reduced the bioaccessible acrylamide compared with isolated biscuits (from 212 to 122 ng; p < 0.05). The presence of protein sources (egg or meat steak) in the potato-based products significantly decreased the acrylamide bioaccessibility, which was more prominent in the French fries-meat steak system (from 2100 to 1698 ng; p < 0.05). These findings establish the importance of considering complete meals and not only isolated foods as well as the study of the non-bioaccessible fractions for a better understanding of acrylamide bioaccessibility, its recovery and interactions during gastrointestinal digestion.

Characterization and application of a coating of starch extracted from avocado (Persea americana L. cv. Hass) seeds as an alternative to reduce acrylamide content in French fries.

The starch extracted from avocado (Persea americana L. cv. Hass) seeds was characterized and used in the preparation of an edible coating to reduce the oil uptake and acrylamide content in French fries. Starch characterization was carried out using Differential Scanning Calorimetry, Fourier transform infrared spectrophotometry, gelatinization, and scanning electron microscopy. Uncoated (UFF) and coated (CFF) French fries were compared and evaluated for moisture, water activity (Aw), fat, color, firmness, acrylamide content, and sensorial analysis. The extracted starch presented a high crystalline structure and good stability to mechanical work and heat treatments. The CFF French fries showed significantly higher Aw, color parameter a*, but lower luminosity and acrylamide content than UFF samples. Similarly, the CFF samples tended to decrease the fat content, although without statistical differences. Avocado seed starch can be an economical and technically feasible alternative to the food industry as an effective coating to reduce acrylamide content in French fries.

[Relevance of Surface-Exposed Lysine Residues Designed for Functionalization of Laccase].

Fungal laccases are oxidoreductases with low-specificity for substrates. The characterization of laccase's surface is a prerequisite used to obtain hybrid catalysts with new properties. Surface-exposed lysine residues are targets in immobilization reactions. In this work, LAC3-K0, an enzyme devoid of lysine, was used as a platform to detect potential surface-exposed sites suitable for replacement with a lysine residue. Seven sites were selected from a LAC3-K0 3-D model, and single lysine mutants (UNIKn, n = residue number) were obtained by site-directed mutagenesis. All mutants were expressed in Saccharomyces cerevisiae W303-1A and detected as functional secreted proteins by their ability to oxidize guaiacol or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) on agar plates. All variants were active at acidic pH but presented no activity at neutral pH, as expected. Likewise, variants were stable a temperature between 15-55°C, and were completely inactivated at 70°C. Oxidation assays revealed that the replacement of one or two surface residues with lysine greatly affected enzyme activity and substrate specificity. The catalytic; parameters (KM^(app) and kcat^(app)) determined with ABTS were found to be different among the variants; Vmax^(app) was 1.5-2 fold higher in UNIK269 and triple mutant, with a KM^(app) of 0.27 and 0.30, respectively; kcat^(app )was 30.25 in UNIK238 and 32.34 in the triple mutant. The role of hydrophobic patches detected on the surface of LAC3-K0 was determined to be a favorable factor to be considered in the interaction of hybrid materials. All variants with uniquely surface located lysine created in this work can be in demand for obtaining laccases with a certain substrate specificity in the design of hybrid materials.

Monolithic integration of a 10 µm cut-off wavelength InAs/GaSb type-II superlattice diode on GaAs platform.

At room temperature, a 10 µm cut-off wavelength coincides with an infrared spectral window and the peak emission of blackbody objects. We report a 10 µm cut-off wavelength InAs/GaSb T2SL p-i-n diode on a GaAs substrate with an intentional interfacial misfit (IMF) array between the GaSb buffer layer and GaAs substrate. Transmission electron microscopy and energy-dispersive X-ray spectroscopy revealed that the heterostructure on GaSb-on-GaAs is epitaxial, single-crystalline but with a reduced material homogeneity, extended lattice defects and atomic segregation/intermixing in comparison to that on the GaSb substrate. Strain-induced degradation of the material quality is observed by temperature-dependent current-voltage measurements. The T2SL with the IMF array appears as a potentially effective route to mitigate the impact of the lattice mismatch once its fabrication is fully optimized for these systems, but additional strain compensating measures can enable a low cost, scalable manufacturing of focal plane arrays (FPA) for thermal imaging cameras for spectroscopy, dynamic scene projection, thermometry, and remote gas sensing.

[Concomitant Ulcerative Colitis and Neurofibromatosis type 1: possible common origin?] / Colitis Ulcerosa y Neurofibromatosis tipo 1 concomitantes: ¿posible origen común?

In the last 15 years, 3 cases of concurrent Ulcerative Colitis with Neurofibromatosis Type 1 have been described in adults and adolescents, but not in children; although it may be a casual finding, a com mon pathogenic pathway between both diseases is postulated, based on mast cell dysregulation in the gastrointestinal tract. OBJECTIVE: To report the clinical case of a toddler with onset of concomitant Ulcerative Colitis with CMV infection, with history of Neurofibromatosis Type 1, and to discuss the common origin between both diseases. CLINICAL CASE: We describe the case of a 2-and-a-half-year-old toddler with history of Neurofibromatosis Type 1 who presented with bloody diarrhea. On endos copic examination, the mucosa from the anal margin to the cecum was erythematous, with loss of vascular transparency. Biopsies of colonic mucosa showed signs of chronic inflammation, consistent with the diagnosis of Ulcerative Colitis, and CMV infection was diagnosed by PCR. CONCLUSION: Previous studies have suggested that mast cells may have a pathogenic role in the development of UC, however, the clinical significance of these findings is unknown. Future research is needed to further investigate the role of mast cells in the development of UC and to confirm a genetic association bet ween the two diseases.

Intercellular communication and the organization of simple multicellular animals.

Animal cells are amazing examples of decentralized systems: By interchanging information about their position and internal state, cells coordinate their behavior and organize themselves in time and space. Examples of this behavior are the development of an embryo or of an organoid. In this work we have asked which are the "rules of intercellular relationship" that allow the organization of an abstract cell collective into structures similar to simple metazoans, without being specific about the (molecular, cellular or physical) nature of the processes involved. To do so, we have used a computational modeling approach following a modified version of the "Swarmalator" concept introduced by O'Keeffe, Hong and Strogatz (2017): a collection of interacting particles ("swarmalators"), each of which defined by a position in space and an internal state (a phase). The key feature is that swarmalators are coupled, so that their position and internal state are both affected by the position and state of all other swarmalators. This model can be easily analogized to biological systems, with "cells" being the swarmalators, and their phase the cell's internal state or "cell type". With this model we explore the conditions (represented by the coupling parameters) that would allow the organization of a multicellular "bioswarmer" and its dynamics along a sort of life cycle. Originally developed in 2D, we implement the model in 3D as well. We describe how changing the strength of intercellular communication can alter the structure and differentiation state of the bioswarmer, how internal polarization can arise and trigger collective directed migration, or how partly erasing the cellular memory of cell state is critical to allow bioswarmers to transit through different states. In addition, we show that the size of a multicellular ensemble might control the differentiation of its constituent cells without changing its rules of relationship.

[Complex extraction of Küntscher nails. Trephines and other surgical strategies]. / Extracción compleja de clavos de fémur tipo Küntscher. Trefinas y otras técnicas.

INTRODUCTION: Removing an intact or broken intramedullary nail can be a real surgical challenge. In clinical cases many methods have been described, and there are many tools to allow their extraction. In this article, the experience in one of them is presented: the use of trephines. CLINICAL CASES: Three cases of Küntscher intramedullary nails are described, in which it was used, also listing in detail the steps to be followed in a nail extraction, arranging the techniques and assorted tools required to take the nail out, enable the surgeon to make a better extraction plan and prepare in advance any of the necessary resources in the case of failure during the surgery. CONCLUSION: The use of trephines as an extraction system is an infrequent technique. It can be an alternative when the usual methods fail. It does not require new approaches, does not require the integrity of the proximal end of the nail, and can be used in most designs.

INTRODUCCIÓN: La extracción de un clavo intramedular íntegro o roto puede ser un verdadero desafío quirúrgico. Mediante casos clínicos se han descrito diferentes métodos y existen multitud de herramientas que permiten su retirada. En este artículo se presenta la experiencia de una de ellas: el uso de trefinas. CASOS CLÍNICOS: Se describen tres instancias de clavos intramedulares tipo Küntscher detallando los pasos a seguir en una extracción, tras revisar y organizar las técnicas publicadas y las distintas herramientas que se precisan en su realización, de forma que el cirujano pueda planificar mejor la remoción y disponga de los recursos necesarios para poder realizarlas progresivamente si van fracasando durante la cirugía. CONCLUSIÓN: El uso de trefinas como sistema de extirpación es una modalidad poco utilizada, reproducible como alternativa cuando fallan los métodos habituales. No requiere nuevos abordajes y no precisa de la integridad del extremo proximal del elemento, pudiendo ser utilizada en la mayoría de los diseños.

Sarcoidosis y esplenomegalia masiva: un dilema diagnóstico / Sarcoidosis and massive splenomegaly: a diagnostic dilemma

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Stability of focusing regions and its vortex-solitonic properties.

Focusing regions, also known as caustic regions, are the singular solutions to the amplitude function of optical fields. Focusing regions are generated by the envelope curve of a set of critical points, which can be of attractor or repulsor type. The nature of the critical point depends on the refractive index. An important property of the critical points is that they present charge-like features. When a focusing region is generated in media with a random refractive index, current-like effects appear, and the evolution of the focusing regions follows a diffusion behavior. The morphology of the focusing regions may generate vortices or "eternal solutions" of solitonic type in a nonlinear medium. Herein, the condition under which these effects occur is analyzed and experimentally corroborated.

Oscillatory behavior in a system of swarmalators with a short-range repulsive interaction.

One of the computational models proposed to study emerging phenomena in decentralized systems is the swarmalator model [Nat. Commun. 8, 1504 (2017)2041-172310.1038/s41467-017-01190-3], where only long-range interactions are considered. But in living systems many of the collective behaviors observed arise from the combined effect of long- and short-range interactions. In this work we present an extension to the swarmalator model which includes a Gaussian short-range repulsive term of the type 1/σe^{-|x|^{2}/σ} along with the results of numerical simulations. Using several order parameters we can distinguish between static and dynamic aggregations and between synchronous and asynchronous states. We have found six long-term collective states, some of them not previously reported and the most remarkable one showing oscillatory collective behavior. The results obtained show a multiplicity of complex behaviors that extend the applicability of the swarmalator model.

Modelization of anaerobic processes during co-digestion of slowly biodegradable substrates.

The influence of the soluble substrates over the anaerobic processes has been extensively investigated, but little is known about the effects of particulate substrate. The biodegradation of these substrates starts with the hydrolytic step, this process is slower than the other ones involved in the biodegradation of particulate substrates and usually becomes the rate-limiting step. This study investigate the effect of the initial total solids (TS) concentration on the anaerobic co-digestion of two slowly biodegradable organic substrates. The wastes mixtures were prepared at different dilutions in the range from 10% to 28% TS. From these experiments it was observed that as TS concentration increased, the methane production decreased. These results were modelled and it was observed that neither hydrolysis nor fermentation stages controlled the methane production rate. Being a substrate inhibition event experienced at the methanogenic stage the responsible of the lower methane production when operating at high TS concentrations.

Impact of the consumer cooking practices on acrylamide formation during the preparation of French fries in Spanish households.

An observational study in 208 volunteers in households from 30 Spanish provinces was conducted from May to June 2017 in order to evaluate the formation of acrylamide during the preparation of French fries from fresh potatoes. Consumer cooking practices and household typology were evaluated with an ad-hoc questionnaire. Potatoes (fresh and fried) and frying oil were collected from the households. A total of 36.1% of samples contained acrylamide above the benchmark level for French fries (500 µg kg-1). The mean acrylamide content (550 µg kg-1) and P95 (1747 µg kg-1) were higher than values reported by EFSA (308 µg kg-1 and 971 µg kg-1, respectively). Although the colour 'golden' was the criteria to decide the end-point of frying, nearly 40% of the consumers misclassified it. Acrylamide was significantly correlated with the colour parameter a*, even in this random scenario of frying practices, and is able to distinguish above and below the established benchmark level of 500 µg kg-1 for acrylamide.