Environmental factors play a significant role in well-being of laboratory animals. Regulations and guidelines recommend, if not require, that stressors such as bright lighting, smells, and noises are ...eliminated or reduced to maximize animal well-being. A factor that is often overlooked is handling and how researchers interact with their animals. Researchers, lab assistants, and husbandry staff in animal facilities may use inconsistent handling methods when interacting with rodents, but humans should be considered a part of the animal’s social environment. This study examined the effects of different handling techniques on depressive-like behavior, measured by the Porsolt forced swim test, in adult C57BL/6J male mice. The same two researchers handled the mice in a gentle, aggressive, or minimal (control) fashion over approximately two weeks prior to testing. The results demonstrated a beneficial effect of gentle handling: gentle handling reduced swimming immobility in the forced swim test compared to mice that were aggressively or minimally handled. We argue that gentle handling, rather than methodical handling, can foster a better relationship between the handlers and rodents. Although handling is not standardized across labs, consistent gentle handling allows for less challenging behavioral testing, better data collection, and overall improved animal welfare.
Surface enhanced Raman spectroscopy (SERS) measurements are conventionally performed using assemblies of metal nanostructures on a macro- to micro-sized substrate or by dispersing colloidal metal ...nanoparticles directly onto the sample of interest. Despite intense use, these methods allow neither the removal of the nanoparticles after a measurement nor a defined confinement of the SERS measurement position. So far, tip enhanced Raman spectroscopy is still the key technique in this regard but not adequate for various samples mainly due to diminished signal enhancement compared to other techniques, poor device fabrication reproducibility, and cumbersome experimental setup requirements. Here, we demonstrate that a rational combination of only four gold nanoparticles (AuNPs) on a DNA origami template, and single silicon nanowires (SiNWs) yield functional optical amplifier nanoprobes for SERS. These nanoscale SERS devices offer a spatial resolution below the diffraction limit of light and still a high electric field intensity enhancement factor (EF) of about 105 despite of miniaturization.
This article of reflection considers socio-political issues such as linguistic imperialism, native speakerism, English as an International language, and appropriate teaching methodologies, which are ...currently contentious issues in the ELT community. Framed within a critical approach of applied linguistics, these issues are addressed in three sections (global/local tensions, teacher professional identity, and a new EFL professional identity) in order to argue that a dynamic, shifting, and multifaceted perspective of a globally-minded EFL teacher professional identity is needed so that Colombian EFL professionals can define or redefine their own identities in taking an informed and critical political stance.
To ensure that a structure will last throughout its service life, repairing reinforced concrete entails, among others, correctly marking off the area affected by aggressive agents that may ...deteriorate both the concrete and the steel. Chloride, the most damaging source of reinforcement corrosion, may diffuse to a greater or lesser distance from the surface depending on the ease of penetration. In this study, we calibrated a handheld X-ray fluorescence analyser (hXRF) and used it to quantify the chloride concentration in cement-based materials. The findings were verified against a series of samples of known concentration to establish a suitable correction factor. Chloride ions were quantified precisely and accurately with the hXRF instrument, and we calculated a correction factor of 1.16. The instrument and the information recorded were used to quantify the chloride ion content in different parts of an existing structure. The analyser identified apparently healthy areas that could, nonetheless, pose oxidation problems in the near future due to significant chloride concentration. Chloride quantification data at different depths can be used to draw diffusion or penetration profiles and to determine whether ion concentration around the reinforcement is within the recommended limits. The method developed can be applied in situ to quickly locate the most critical areas.
Mycotoxins are secondary metabolites produced by fungi occurring in food that are toxic to animals and humans. Early-life mycotoxins exposure has been linked to diverse pathologies. However, how ...maternal exposure to mycotoxins impacts on the intestinal barrier function of progeny has not been explored. Here, exposure of pregnant and lactating C57Bl/6J female mice to aflatoxin B1 (AFB1; 400 μg/kg body weight/day; 3 times a week) in gelatine pellets, from embryonic day (E)11.5 until weaning (postnatal day 21), led to gut immunological changes in progeny. The results showed an overall increase of lymphocyte number in intestine, a reduction of expression of epithelial genes related to microbial defence, as well as a decrease in cytokine production by intestinal type 2 innate lymphoid cells (ILC2). While susceptibility to chemically induced colitis was not worsened, immune alterations were associated with changes in gut microbiota and with a higher vulnerability to infection by the protozoan Eimeria vermiformis at early-life. Together these results show that maternal dietary exposure to AFB1 can dampen intestinal barrier homeostasis in offspring decreasing their capability to tackle intestinal pathogens. These data provide insights to understand AFB1 potential harmfulness in early-life health in the context of intestinal infections.
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•Effect of maternal AFB1 dietary exposure was studied in intestinal mucosa of offspring mice.•Maternal AFB1 exposure leads to lymphocyte expansion and alters cytokine expression.•Maternal AFB1 exposure reduces microbial-related epithelial gene expression in offspring.•Maternal AFB1 exposure modifies offspring gut microbiota.•Maternal AFB1-exposed offspring are more vulnerable to intestinal parasite infection.
To dispose of atomic oxygen, it is necessary the O
activation; however, an energy barrier must be overcome to break the O-O bond. This work presents theoretical calculations of the O
adsorption and ...dissociation on small pure Au
and Ag
and bimetallic Au
Ag
(n + m ≤ 6) clusters using the density functional theory (DFT) and the zeroth-order regular approximation (ZORA) to explicitly include scalar relativistic effects. The most stable Au
Ag
clusters contain a higher concentration of Au with Ag atoms located in the center of the cluster. The O
adsorption energy on pure and bimetallic clusters and the ensuing geometries depend on the spin multiplicity of the system. For a doublet multiplicity, O
is adsorbed in a bridge configuration, whereas for a triplet only one O-metal bond is formed. The charge transfer from metal toward O
occupies the σ*
antibonding natural bond orbital, which weakens the oxygen bond. The Au
(
A) cluster presents the lowest activation energy to dissociate O
, whereas the opposite applies to the AuAg (
A) system. In the O
activation, bimetallic clusters are not as active as pure Au
clusters due to the charge donated by Ag atoms being shared between O
and Au atoms.
The structural systems of residential buildings in many developed countries have widely utilized reinforced concrete as the most common solution in construction systems since the early 20th century. ...The durability of reinforced concrete columns and beams is compromised, in most cases, by pathologies caused by the corrosion of their reinforcements. This study analyses the corrosion processes induced by carbonation in 25 buildings with reinforced concrete structures. The models estimate the service life of reinforced concrete elements by differentiating between the initiation period and the propagation period of damage, considering two possible stages: the time of corrosion propagation until the cracking of the concrete cover, and the time of propagation until a loss of section is considered unacceptable for structural safety. However, the mathematical expressions that model the propagation periods consider the same corrosion rate in both cases. This research has found that the average corrosion rate in elements with an unacceptable loss of reinforcement section was in the order of 8 times higher than the corrosion rate in cracked columns and beams without a loss of reinforcement. This opens up a path to improve the definition of the different stages experienced by a reinforced concrete element suffering corrosion of its reinforcements due to carbonation, because once the concrete has cracked, the corrosion rate increases significantly.
Anatase TiO2 presents a large bandgap of 3.2 eV, which inhibits the use of visible light radiation (λ > 387 nm) for generating charge carriers. We studied the activation of TiO2 (101) anatase with ...visible light by doping with C, N, S, and F atoms. For this purpose, density functional theory and the Hubbard U approach are used. We identify two ways for activating the TiO2 with visible light. The first mechanism is broadening the valence or conduction band; for example, in the S-doped TiO2 (101) system, the valence band is broadened. A similar process can occur in the conduction band when the undercoordinated Ti atoms are exposed on the TiO2 (101) surface. The second mechanism, and more efficient for activating the anatase, is to generate localized states in the gap: N-doping creates localized empty states in the bandgap. For C-doping, the surface TiO2 (101) presents a “cleaner” gap than the bulk TiO2, resulting in fewer recombination centers. The dopant valence electrons determine the number and position of the localized states in the bandgap. The formation of charge carriers with visible light is highly favored by the oxygen vacancies on TiO2 (101). The catalytic activity of C-doping using visible radiation can be explained by its high absorption intensity generated by oxygen vacancies on the surface. The intensity of the visible absorption spectrum of doped TiO2 (101) follows the order: C > N > F > S dopant.
The co-occurrence of COVID-19 with endemic diseases is a public health concern that may affect patient prognosis and outcomes. The objective of this study was to describe the clinical characteristics ...of patients with dengue virus (DENV) and SARS-CoV-2 co-infections and compare their outcomes against those of COVID-19 patients without dengue. A cross-sectional study was conducted in patients with SARS-CoV-2 infection who attended a single center in Cali, Colombia, from March 2020 to March 2021. All patients who were tested by both real-time polymerase chain reaction for SARS-CoV-2 and IgM/NS1 for DENV were included. Dengue was diagnosed as having either an IgM- or an NS1- positive test. A total of 90 patients were included (72 with COVID-19 only and 18 with co-infection). Patients with co-infection had more dyspnea (61.1% versus 22.2%; P = 0.003) as well as higher oxygen desaturation (53.3% versus 13.4%; P = 0.002) and neutrophil-to-lymphocyte ratio (5.59 versus 3.84; P = 0.038) than patients with COVID-19 alone. The proportion of patients classified with moderate to severe COVID-19 was higher in the co-infection group (88.3% versus 47.8%; P = 0.002). Also, co-infection was associated with an increased need for mechanical ventilation (P = 0.06), intensive care unit (ICU) initial management (P = 0.02), and ICU admission during hospitalization (P = 0.04) compared with COVID-19 only. The ICU mortality rate was 66.6% in patients with co-infection versus 29.4% in patients infected with only SARS-CoV-2 (P < 0.05). The possibility of DENV and SARS-CoV2 co-infection occurred in the convergence of both epidemic waves. Co-infection was associated with worse clinical outcomes and higher mortality in ICU-admitted patients than in patients with the COVID-19 only.
Alkali‐intercalated graphite compounds represent a compelling modification of carbon with significant application potential and various fundamentally important phases. The intercalation of graphite ...with alkali atoms (Li and K) using liquid ammonia solution as a mediating agent is reported. Alkali atoms dissolve well in liquid ammonia, which simplifies and speeds up the intercalation process, and it also avoids the high temperature formation of alkali carbides. Optical microscopy, Raman, and electron spin‐resonance spectroscopy attest that the prepared samples are highly and homogeneously intercalated to a level approaching stage‐I intercalation compounds. The method and the synthesis route may serve as a starting point for the various forms of alkali‐atom‐intercalated carbon compounds (including carbon nanotubes and graphene), which can be exploited in energy storage and further chemical modifications.
The intercalation of graphite with alkali atoms using liquid ammonia solution as a mediating agent is reported. Alkali atoms dissolve well in liquid ammonia, which simplifies and speeds up the intercalation process, and it also avoids the high temperature formation of alkali carbides. Optical microscopy, Raman, and electron spin‐resonance spectroscopy attest that the prepared samples are highly and homogeneously intercalated.
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