In the
p
-center problem, it is assumed that the facility located at a node responds to demands originating from the node. This assumption is suitable for emergency and health care services. However, ...it is not valid for large-scale emergencies where most of facilities in a whole city may become functionless. Consequently, residents in some areas cannot rely on their nearest facilities. These observations lead to the development of a variation of the
p
-center problem with an additional assumption that the facility at a node fails to respond to demands from the node. We use dynamic programming approach for the location on a path network and further develop an efficient algorithm for optimal locations on a general network.
Lysosomal degradation of tyrosinase, a pivotal enzyme in melanin synthesis, negatively impacts melanogenesis in melanocytes. Nevertheless, the precise molecular mechanisms by which lysosomes target ...tyrosinase have remained elusive. Here, we identify RING (Really Interesting New Gene) finger protein 152 (RNF152) as a membrane-associated ubiquitin ligase specifically targeting tyrosinase for the first time, utilizing AlphaScreen technology. We observed that modulating RNF152 levels in B16 cells, either via overexpression or siRNA knockdown, resulted in decreased or increased levels of both tyrosinase and melanin, respectively. Notably, RNF152 and tyrosinase co-localized at the trans-Golgi network (TGN). However, upon treatment with lysosomal inhibitors, both proteins appeared in the lysosomes, indicating that tyrosinase undergoes RNF152-mediated lysosomal degradation. Through ubiquitination assays, we found the indispensable roles of both the RING and transmembrane (TM) domains of RNF152 in facilitating tyrosinase ubiquitination. In summary, our findings underscore RNF152 as a tyrosinase-specific ubiquitin ligase essential for regulating melanogenesis in melanocytes.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Major depression is a highly prevalent mood disorder, affecting about 350 million people, and around 30% of the patients are resistant to currently available antidepressant medications. Recent ...evidence from a randomized controlled trial (RCT) supports the rapid antidepressant effects of the psychedelic ayahuasca in treatment-resistant depression. The aim of this study was to explore the effect of ayahuasca on plasma cortisol and awakening salivary cortisol response, in the same group of treatment-resistant patients (MD) and in healthy volunteers (C). Subjects received a single dose of ayahuasca or placebo (dosing session), and both plasma and awakening salivary cortisol response were measured at baseline (before dosing session) and 48 h after the dosing session. Baseline assessment (D0) showed blunted awakening salivary cortisol response and hypocortisolemia in patients, with respect to healthy controls. Salivary cortisol was also measured during dosing session, and we observed higher increases for both C and MD that ingested ayahuasca than placebo. After 48 h from the dosing session with ayahuasca, patients' awakening salivary cortisol response is similar to the ones detected in controls. No significant changes in plasma cortisol levels were observed 48 h after the sessions. Therefore, these findings point to new evidence on the modulation of salivary cortisol levels as a result of an ayahuasca session, both in healthy and depressive volunteers. Considering that cortisol acts in regulation of distinct physiological pathways, emotional and cognitive processes, it is assumed to be critically involved to the etiology of depression and its regulation seems to be important for the treatment and remission of major depression, ayahuasca use as antidepressant should be further investigated. Moreover, this study highlights the importance of psychedelics in the treatment of human mental disorders.
Passive sampling is a sensitive and efficient method for analyzing pesticides in water. This article describes a hollow fiber liquid-phase microextraction (HF-LPME) device that was improved using ...polypropylene membranes grafted with nanocellulose for the passive sampling of pesticides in water. A comprehensive gas chromatography time-of-flight mass spectrometry (GCxGC/Q-TOFMS) system was used to separate, identify, and quantify pesticides. The sampling rates of 38 moderately hydrophobic to hydrophobic agricultural pesticides (2.18 < log Kow < 6.89) from different chemical classes, including the main triazine, organochlorine and organophosphate compounds, were calculated. A calibration process was applied to evaluate the role of flow velocity and select potential candidates for a possible performance reference compound (PRC). Sampling rates varied between 0.17 mL d-1 and 23.15 mL d-1. The accumulation curves identified linear periods ranging from 3 to 18 days. The new passive sampler device was applied for 8 days in rivers and marginal lagoons of natural parks of the São Francisco basin in Minas Gerais, Brazil and identified 10 target pesticides. Furthermore, 10 non-targeted pesticides were detected by the GCxGC/Q-TOFMS method.
This research describes a solid-phase microextraction device using carbon nanomaterials supported on steel threads. The device was used to pre-concentrate and extract 24 pesticides in water. The ...carbon nanomaterials were obtained by a chemical vapor deposition (CVD) process, using methane and acetonitrile as carbon source. The different pesticides were separated, detected, and quantified using gas chromatography coupled to mass spectrometry (GC-MS). The system, optimized and validated in the laboratory, presented good results. Linearity was between 0.0007 and 50.00 μg L−1, with determination coefficients greater than 0.9. The detection and quantification limits were in the range of 0.0002–1.1309 μg L−1 and 0.0007–3.7320 μg L−1, respectively. The studied pesticides presented recovery values in the range of 70 ± 8 to 123 ± 18%. Carbon nanomaterials exhibited high thermal and mechanical resistance, as the same fiber could be used for approximately 300 extractions. The device was applied to analyze environmental water samples collected from the São Francisco river basin in Brazil and in the Chinampas in Mexico City.
Display omitted
•Manufacture of a microextraction syringe with carbon nanomaterials as receiving phase.•Optimization and validation of a method for pesticide analysis in water. Validation parameters showed satisfactory results.•Application of carbon nanomaterial microextraction syringe in water sources.•Some pesticides banned in agriculture continue to be detected in Brazilian environmental water.
The food environment can influence opportunities and barriers to food access. This study aimed to investigate whether access to healthy foods varies according to store types and the socioeconomic ...status of the users of the public health promotion program in Brazil, known as the Health Academy Program.
A total of 18 Health Academy Program centers were selected via simple conglomerate sampling. Health Academy Program users living up to 1 km from the food stores were evaluated (n = 2831). Their socioeconomic status was investigated via face-to-face interviews. The food stores were audited through direct observation. Variables included the community nutrition environment (type and location) and consumer nutrition environment (healthy food store index, involving variables such as availability, variety, and advertising of healthy and unhealthy products). Multiple linear regression analysis was performed to examine the association between access to healthy foods, socioeconomic status, and food store type.
A total of 336 stores were investigated. The majority were specialty fruit and vegetable markets/stores or open-air food markets. Access to healthy food was only associated with the food store type. An increase of 1% in the availability of specialized fruits and vegetable markets or open-air food markets and supermarket raised healthy food store index values by 0.12 and 0.07, respectively.
Public food supply policies aimed at improving the diet quality of the population and reducing inequality in access should prioritize the implementation of stores of better quality, such as specialty fruit and vegetable markets and open-air food markets.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Homogeneous dispersion of carbon nanotubes (CNTs) in polymers has significantly improved their processing and application as nanomaterials. Generally, CNTs tend to agglomerate due to their high ...aspect ratios and strong van der Waals interaction. Surface functionalization appears to be a solution to this problem. This study presents a controlled dispersion of carbon nanotubes in polyethylene through surface modification using a mixture of concentrated acid and octadecylamine (ODA). CNTs were characterized by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, and transmission electron microscopy. The results confirmed that carboxyl and alkane groups were successfully introduced on CNT surfaces. The acid- and amine-functionalized carbon nanotubes were dispersed in four solvents with different polarities (water, ethanol, acetone, and xylene) to correlate the degree of dispersion of CNT with their polarity. The results showed that CNT dispersion stability strongly depends on solvent and carbon nanotube polarities after the functionalization step. The nanohardness and tensile tests showed that the addition of CNTs, especially the functionalized with ODA, leaded the polymer harder, increasing its Young’s modulus and tensile strength. However, its toughness and deformation capacity were reduced. The potential applications of CNT-based polymer nanocomposites broaden considerably due to the surface engineering of carbon nanotubes.
Snow is a unique microhabitat, despite being a harsh environment, multiple life forms have adapted to survive in it. While algae, bacteria and fungi are dominant microorganisms in Antarctic snow, ...little is known about other organisms that may be present in this habitat. We used metabarcoding to investigate DNA sequence diversity of non-fungal eukaryotes present in snow obtained from six different sites across the Maritime Antarctica. A total of 20 taxa were assigned to obtained sequences, representing five Kingdoms (Chromista, Protozoa, Viridiplantae and Metazoa) and four phyla (Ciliophora, Cercozoa, Chlorophyta and Cnidaria). The highest diversity indices were detected in Trinity Peninsula followed by Robert Island, Arctowski Peninsula, Deception Island, King George Island and Snow Island. The most abundant assignments were to Trebouxiophyceae, followed by
Chlamydomonas nivalis
and Chlamidomonadales. No taxa were detected at all sites. Three potentially new records for Antarctica were detected: two Ciliophora (
Aspidisca magna
and
Stokesia
sp.) and the green algae
Trebouxia potteri
. Our data suggested that similarities found between the sites may be more related with snow physicochemical properties rather than geographic proximity or latitude. This study provides new insights into the diversity and distribution of eukaryotic organisms in Antarctic snow.
In this study, the removal of methylene blue (MB) from aqueous solution by peat was analyzed. The peat was collected from a peatland at Arroio do Silva Beach, in Santa Catarina state, in the south of ...Brazil. Adsorption was conducted using varied initial concentrations of the MB solutions and three different temperatures (35, 45 and 60
°C). An adsorption time of around 4.5
h was sufficient to reach the equilibrium for all temperatures, in the concentration range studied. Percentage removal was greater for diluted solutions, but the absolute amount of MB adsorbed by the peat at equilibrium increased with an increase of the initial concentration, corroborating the efficacy of the material as an adsorbent. Temperature influenced slightly the reaction, which was endothermic. Results indicated a multi-layered process and the data were analyzed considering pseudo-first-order, pseudo-second-order and intraparticle diffusion approaches. The latter two mechanisms seem to be significant in the rate-controlling step.
The conducting polymer, poly(3,4-ethylenedioxythiophene)-polystyrenesulfonic acid (PEDOT:PSS), is certainly one of the most important substitute materials for indium tin oxide in organic devices. Its ...metallic conductivity and transmittance bring favorable perspectives for organic photovoltaic applications. Although graphene oxide (GO) is not a good conductor, it can form high-quality thin films and can be transparent, and additionally, GO is an inexpensive material and can be easily synthesized. This study investigated how the conductivity of a composite film of graphene oxide (GO) and different amounts of PEDOT:PSS can be modified. The effects of GO:PEDOT:PSS composites with several PEDOT:PSS proportions were analyzed in regards to the composite molecular structure and ordering, charge transfer dynamics (in the femtosecond range), electrical properties and morphology. For the best conductivity ratio GO found with 5% PEDOT:PSS, a solvent treatment was also performed, comparing the resistivity of the film when treated with dimethyl sulfoxide (DMSO) and with ethylene glycol.
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