923 research outputs found
Mechanisms Associated to Nitroxyl (HNO)-Induced Relaxation in the Intestinal Smooth Muscle
The pharmacological properties of nitroxyl (HNO) donors in the gastrointestinal tract are unknown. We investigated the properties of this molecule in the regulation of gastrointestinal contractility focusing on its possible interaction with other gaseous signaling molecules such as NO and HS. Organ bath, Ca 2+ imaging, and microelectrode recordings were performed on rat intestinal samples, using Angeli's salt as HNO donor. Angeli's salt caused a concentration-dependent relaxation of longitudinal or circular muscle strips of the ileum and the proximal colon. This relaxation was strongly inhibited by the Rho-kinase inhibitor Y-27632 (10 μM), by the reducing agent DTT or by the inhibitor of soluble guanylate cyclase (sGC) ODQ (10 μM) alone or in combination with the inhibitors of the endogenous synthesis of HS β-cyano--alanine (5 mM) and amino-oxyacetate (5 mM). Preventing endogenous synthesis of NO by the NO synthase inhibitor L-NAME (200 μM) did not affect the relaxation induced by HNO. HNO induced an increase in cytosolic Ca 2+ concentration in colonic myocytes. It also elicited myocyte membrane hyperpolarization that amounted to −10.6 ± 1.1 mV. ODQ (10 μM) and Apamin (1 μM), a selective inhibitor of small conductance Ca 2+ -activated K + channels (SKca), strongly antagonized this effect. We conclude that HNO relaxes the gastrointestinal tract musculature by hyperpolarizing myocytes via activation of the sGC/cGMP pathway similarly to NO, not only inhibiting the RhoK and activating MLCP as do both NO and HS but also increasing cytosolic Ca 2+ for activation of SK contributing to hyperpolarization
E. coli infection disrupts the epithelial barrier and activates intrinsic neurosecretory reflexes in the pig colon
This study aims to assess the barrier integrity and possible activation of enteric neural pathways associated with secretion and motility in the pig colon induced by an enterotoxigenic Escherichia coli (ETEC) challenge. 50 Danbred male piglets were used for this study. 16 were challenged with an oral dose of the ETEC strain F4+ 1.5 × 109 colony-forming unit. Colonic samples were studied 4- and 9-days post-challenge using both a muscle bath and Ussing chamber. Colonic mast cells were stained with methylene blue. In control animals, electrical field stimulation induced neurosecretory responses that were abolished by tetrodotoxin (10−6M) and reduced by the combination of atropine (10−4M) and α-chymotrypsin (10U/mL). Exogenous addition of carbachol, vasoactive intestinal peptide, forskolin, 5-HT, nicotine, and histamine produced epithelial Cl− secretion. At day 4 post-challenge, ETEC increased the colonic permeability. The basal electrogenic ion transport remained increased until day 9 post-challenge and was decreased by tetrodotoxin (10−6M), atropine (10−4M), hexamethonium (10−5M), and ondansetron (10−5M). In the muscle, electrical field stimulation produced frequency-dependent contractile responses that were abolished with tetrodotoxin (10−6M) and atropine (10−6M). Electrical field stimulation and carbachol responses were not altered in ETEC animals in comparison with control animals at day 9 post-challenge. An increase in mast cells, stained with methylene blue, was observed in the mucosa and submucosa but not in the muscle layer of ETEC-infected animals on day 9 post-challenge. ETEC increased the response of intrinsic secretory reflexes and produced an impairment of the colonic barrier that was restored on day 9 post-challenge but did not modify neuromuscular function
Simulación de la cámara de combustión de una caldera pitotubular utilizando la herramienta computacional ansys
This article analyzes the combustion reaction between the fuel (ACPM) and combustion (AIR) that occurs inside the combustion chamber of a pyrotubular boiler using Ansys® software and selecting the fluent method (CFD), being the indicated one To simulate fluids. A study of the behavior of the temperature and pressure through the total length of the combustion chamber and in turn the molar and mass fractions of the products resulting from the combustion. The results of the variables were compared with the approach of a mathematical model implemented in the simulink tool, taking into account the same conditions and the ACPM fuel.En este artículo se analiza la reacción de combustión entre el combustible (ACPM) y comburente (AIRE) que ocurre al interior de la cámara de combustión de una caldera piro tubular empleando el software Ansys® y seleccionando el método fluent (CFD) [2], siendo el indicado para simular fluidos en procesos de combustión. Se realizó un estudio del comportamiento de la temperatura y presión a través de la longitud total de la cámara de combustión y a su vez las fracciones molares y másicas de los productos resultantes de la combustión ,, Y . Los resultados de las variables fueron comparados con el desarrollo de un modelo matemático implementado en la herramienta Simulink®, teniendo en cuenta las mismas condiciones y el combustible ACPM.
Circular Design Project – Open knowledge co-creation for circular economy education
Design has a key role to play in developing innovative solutions to current local and global
challenges – approaches that must consider the needs of end users and integrate sustainability
criteria in processes and strategies for creating products and services.
The Circular Design – Learning for Innovative Design for Sustainability (L4IDS) project is a
three years Erasmus+ Knowledge Alliance financed project, within the social business and the
educational innovation field. The project’s goal is to support the development of skills
necessary to promote sustainable production and consumption of products and services in
Europe. This is achieved through a knowledge co-creation process and a collaborative action
research framework, which led to the development of training materials in order to teach and
train students, academics and enterprise staff in Innovative Design for Sustainability (IDfS)
strategies. The project is aligned with European Circular Economy policies and contributes to
the realization of a more sustainable society.
The project has four objectives: (1) to increase and improve the learning strategies of Design
for Sustainability; (2) to gather and cluster open educational resources and training courses for
industry staff and academics in Innovative Design for Sustainability; (3) to train up innovative
and entrepreneurial students designers who are capable of dealing with a transition towards
Design for Sustainability as a mainstream design approach, and (4) to establish a basis for a
permanent and active European Network of Design for Sustainability.
The project was formed by 12 partners who are organised around four country hubs in Ireland,
The Netherlands, Catalonia and Sweden. Each country hub consists of one university with
education and research in Sustainable Design, one design company with expertise in
sustainable design and one national design association.
The researchers and professionals involved with the project demonstrate how an
interdisciplinary co-design approach tackling wicked design problems can develop viable
sustainable and product service systems in partnership with SMEs and students. Following
this line of thought, this paper will introduce an internship programme that builds a
collaboration among institutions and businesses, while enabling novice designers to
experience real-life challenges and developing sustainable design solutions that can transform
business practices to address issues of sustainability. Therefore, a total of 11 projects were
performed by 48 interns and 16 industry partners. Addressing environmental problems 7 of
them were focused on sustainable product solutions and 4 of them offered solutions to enhance
the implementation of circular processes in the urban environment.
As a reinforcement for the project’s mission, it was recognized as a best practice under the
umbrella of the World Environment Day, promoted by the Barcelona City Council.Postprint (published version
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Sources, distribution, and acidity of sulfate–ammonium aerosol in the Arctic in winter–spring
We use GEOS-Chem chemical transport model simulations of sulfate–ammonium aerosol data from the NASA ARCTAS and NOAA ARCPAC aircraft campaigns in the North American Arctic in April 2008, together with longer-term data from surface sites, to better understand aerosol sources in the Arctic in winter–spring and the implications for aerosol acidity. Arctic pollution is dominated by transport from mid-latitudes, and we test the relevant ammonia and sulfur dioxide emission inventories in the model by comparison with wet deposition flux data over the source continents. We find that a complicated mix of natural and anthropogenic sources with different vertical signatures is responsible for sulfate concentrations in the Arctic. East Asian pollution influence is weak in winter but becomes important in spring through transport in the free troposphere. European influence is important at all altitudes but never dominant. West Asia (non-Arctic Russia and Kazakhstan) is the largest contributor to Arctic sulfate in surface air in winter, reflecting a southward extension of the Arctic front over that region. Ammonium in Arctic spring mostly originates from anthropogenic sources in East Asia and Europe, with added contribution from boreal fires, resulting in a more neutralized aerosol in the free troposphere than at the surface. The ARCTAS and ARCPAC data indicate a median aerosol neutralization fraction [NH4+]/(2[SO42−] + [NO3−]) of 0.5 mol mol−1 below 2 km and 0.7 mol mol−1 above. We find that East Asian and European aerosol transported to the Arctic is mostly neutralized, whereas West Asian and North American aerosol is highly acidic. Growth of sulfur emissions in West Asia may be responsible for the observed increase in aerosol acidity at Barrow over the past decade. As global sulfur emissions decline over the next decades, increasing aerosol neutralization in the Arctic is expected, potentially accelerating Arctic warming through indirect radiative forcing and feedbacks.Chemistry and Chemical Biolog
Practical Indicators for Risk of Airborne Transmission in Shared Indoor Environments and Their Application to COVID-19 Outbreaks
Some infectious diseases, including COVID-19, can undergo airborne transmission. This may happen at close proximity, but as time indoors increases, infections can occur in shared room air despite distancing. We propose two indicators of infection risk for this situation, that is, relative risk parameter (Hr) and risk parameter (H). They combine the key factors that control airborne disease transmission indoors: viruscontaining aerosol generation rate, breathing flow rate, masking and its quality, ventilation and aerosol-removal rates, number of occupants, and duration of exposure. COVID-19 outbreaks show a clear trend that is consistent with airborne infection and enable recommendations to minimize transmission risk. Transmission in typical prepandemic indoor spaces is highly sensitive to mitigation efforts. Previous outbreaks of measles, influenza, and tuberculosis were also assessed. Measles outbreaks occur at much lower risk parameter values than COVID-19, while tuberculosis outbreaks are observed at higher risk parameter values. Because both diseases are accepted as airborne, the fact that COVID-19 is less contagious than measles does not rule out airborne transmission. It is important that future outbreak reports include information on masking, ventilation and aerosol-removal rates, number of occupants, and duration of exposure, to investigate airborne transmission
Different responses of the blockade of the P2Y1 receptor with BPTU in human and porcine intestinal tissues and in cell cultures
Background: Gastrointestinal smooth muscle relaxation is accomplished by activation of P2Y 1 receptors, therefore this receptor plays an important role in regulation of gut motility. Recently, BPTU was developed as a negative allosteric modulator of the P2Y 1 receptor. Accordingly, the aim of this study was to assess the effect of BPTU on purinergic neurotransmission in pig and human gastrointestinal tissues. Methods: Ca 2+ imaging in tSA201 cells that express the human P2Y 1 receptor, organ bath and microelectrodes in tissues were used to evaluate the effects of BPTU on purinergic responses. Key results: BPTU concentration dependently (0.1 and 1 µmol L −1) inhibited the rise in intracellular Ca 2+ evoked by ADP in tSA201 cells. In the pig small intestine, 30 µmol L −1 BPTU reduced the fast inhibitory junction potential by 80%. Smooth muscle relaxations induced by electrical field stimulation were reduced both in pig ileum (EC 50 = 6 µmol L −1) and colon (EC 50 = 35 µmol L −1), but high concentrations of BPTU (up to 100 µmol L −1) had no effect on human colonic muscle. MRS2500 (1 µmol L −1) abolished all responses. Finally, 10 µmol L −1 ADPβS inhibited spontaneous motility and this was partially reversed by 30 µmol L −1 BPTU in pig, but not human colonic tissue and abolished by MRS2500 (1 µmol L −1). Conclusions & inferences: BPTU blocks purinergic responses elicited via P2Y 1 receptors in cell cultures and in pig gastrointestinal tissue. However, the concentrations needed are higher in pig tissue compared to cell cultures and BPTU was ineffective in human colonic tissue
Detection and attribution of aerosol-cloud interactions in large-domain large-eddy simulations with the ICOsahedral Non-hydrostatic model
Clouds and aerosols contribute the largest uncertainty to current estimates and interpretations of the Earth’s changing energy budget. Here we use a new-generation large-domain large-eddy model, ICON-LEM (ICOsahedral Non-hydrostatic Large Eddy Model), to simulate the response of clouds to realistic anthropogenic perturbations in aerosols serving as cloud condensation nuclei (CCN). The novelty compared to previous studies is that (i) the LEM is run in weather prediction mode and with fully interactive land surface over a large domain and (ii) a large range of data from various sources are used for the detection and attribution. The aerosol perturbation was chosen as peak-aerosol conditions over Europe in 1985, with more than fivefold more sulfate than in 2013. Observational data from various satellite and ground-based remote sensing instruments are used, aiming at the detection and attribution of this response. The simulation was run for a selected day (2 May 2013) in which a large variety of cloud regimes was present over the selected domain of central Europe.
It is first demonstrated that the aerosol fields used in the model are consistent with corresponding satellite aerosol optical depth retrievals for both 1985 (perturbed) and 2013 (reference) conditions. In comparison to retrievals from ground-based lidar for 2013, CCN profiles for the reference conditions were consistent with the observations, while the ones for the 1985 conditions were not.
Similarly, the detection and attribution process was successful for droplet number concentrations: the ones simulated for the 2013 conditions were consistent with satellite as well as new ground-based lidar retrievals, while the ones for the 1985 conditions were outside the observational range.
For other cloud quantities, including cloud fraction, liquid water path, cloud base altitude and cloud lifetime, the aerosol response was small compared to their natural variability. Also, large uncertainties in satellite and ground-based observations make the detection and attribution difficult for these quantities. An exception to this is the fact that at a large liquid water path value (LWP > 200 g m−2), the control simulation matches the observations, while the perturbed one shows an LWP which is too large.
The model simulations allowed for quantifying the radiative forcing due to aerosol–cloud interactions, as well as the adjustments to this forcing. The latter were small compared to the variability and showed overall a small positive radiative effect. The overall effective radiative forcing (ERF) due to aerosol–cloud interactions (ERFaci) in the simulation was dominated thus by the Twomey effect and yielded for this day, region and aerosol perturbation −2.6 W m. Using general circulation models to scale this to a global-mean present-day vs. pre-industrial ERFaci yields a global ERFaci of −0.8 W m
The 2013 face recognition evaluation in mobile environment
Automatic face recognition in unconstrained environments is a challenging task. To test current trends in face recognition algorithms, we organized an evaluation on face recognition in mobile environment. This paper presents the results of 8 different participants using two verification metrics. Most submitted algorithms rely on one or more of three types of features: local binary patterns, Gabor wavelet responses including Gabor phases, and color information. The best results are obtained from UNILJ-ALP, which fused several image representations and feature types, and UC-HU, which learns optimal features with a convolutional neural network. Additionally, we assess the usability of the algorithms in mobile devices with limited resources. © 2013 IEEE
The Selectivity of Milking of Dunaliella salina
The process of the simultaneous production and extraction of carotenoids, milking, of Dunaliella salina was studied. We would like to know the selectivity of this process. Could all the carotenoids produced be extracted? And would it be possible to vary the profile of the produced carotenoids and, consequently, influence the type of carotenoids extracted? By using three different D. salina strains and three different stress conditions, we varied the profiles of the carotenoids produced. Between Dunaliella bardawil and D. salina 19/18, no remarkable differences were seen in the extraction profiles, although D. salina 19/18 seemed to be better extractable. D. salina 19/25 was not “milkable” at all. The milking process could only be called selective for secondary carotenoids in case gentle mixing was used. In aerated flat-panel photobioreactors, extraction was much better, but selectiveness decreased and also chlorophyll and primary carotenoids were extracted. This was possibly related to cell damage due to shear stress
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