430 research outputs found
The Human SLC25A33 and SLC25A36 Genes of Solute Carrier Family 25 Encode Two Mitochondrial Pyrimidine Nucleotide Transporters
The human genome encodes 53 members of the solute carrier family 25 (SLC25), also called the mitochondrial carrier family, many of which have been shown to transport inorganic anions, amino acids, carboxylates, nucleotides, and coenzymes across the inner mitochondrial membrane, thereby connecting cytosolic and matrix functions. Here two members of this family, SLC25A33 and SLC25A36, have been thoroughly characterized biochemically. These proteins were overexpressed in bacteria and reconstituted in phospholipid vesicles. Their transport properties and kinetic parameters demonstrate that SLC25A33 transports uracil, thymine, and cytosine (deoxy)nucleoside di- and triphosphates by an antiport mechanism and SLC25A36 cytosine and uracil (deoxy)nucleoside mono-, di-, and triphosphates by uniport and antiport. Both carriers also transported guanine but not adenine (deoxy)nucleotides. Transport catalyzed by both carriers was saturable and inhibited by mercurial compounds and other inhibitors of mitochondrial carriers to various degrees. In confirmation of their identity (i) SLC25A33 and SLC25A36 were found to be targeted to mitochondria and (ii) the phenotypes of Saccharomyces cerevisiae cells lacking RIM2, the gene encoding the well characterized yeast mitochondrial pyrimidine nucleotide carrier, were overcome by expressing SLC25A33 or SLC25A36 in these cells. The main physiological role of SLC25A33 and SLC25A36 is to import/export pyrimidine nucleotides into and from mitochondria, i.e. to accomplish transport steps essential for mitochondrial DNA and RNA synthesis and breakdown
Phase separations, liquid crystal ordering and molecular partitioning in mixtures of PEG and DNA oligomers
Liquid crystals (LCs) ordering of DNA and RNA oligomers relies on the presence of inter-duplex end-to-end attraction, driving the formation of linear aggregates. Such interactions are gauged, at a macroscopic level, by the osmotic pressure at the isotropic-nematic and nematic-columnar phase transitions. We studied aqueous solutions of PEG and DNA duplex-forming oligomers, finding that there is a wide range of concentrations in which these mixtures phase separate into coexisting PEG-rich and DNA-rich phases, the latter being either in the isotropic state or ordered as a nematic or columnar LC. We determined the phase diagram in mixtures of PEG and DNA duplexes with different terminal motifs\u2013blunt ends, sticky overhangs, aggregation-preventing overhangs\u2013and measured the partitioning of the species in the coexisting phases. On this basis, we determined the osmotic pressure as a function of the DNA concentration across the phase diagram. We compared the equation of state obtained in this way with both the Carnahan\u2013Starling equation of state for hard spheres and with the pressure predicted by computer simulations of a system of aggregating cylinders. We obtain a good agreement between experiments and simulations, and end-to-end attraction energies of the order of 6 kcal/mol, a bit larger than expected, but still in agreement with the current models for DNA-DNA interactions
Cancer cell metabolism in hypoxia: Role of HIF-1 as key regulator and therapeutic target
In order to meet the high energy demand, a metabolic reprogramming occurs in cancer cells. Its role is crucial in promoting tumor survival. Among the substrates in demand, oxygen is fundamental for bioenergetics. Nevertheless, tumor microenvironment is frequently characterized by low-oxygen conditions. Hypoxia-inducible factor 1 (HIF-1) is a pivotal modulator of the metabolic reprogramming which takes place in hypoxic cancer cells. In the hub of cellular bioenergetics, mitochondria are key players in regulating cellular energy. Therefore, a close crosstalk between mitochondria and HIF-1 underlies the metabolic and functional changes of cancer cells. Noteworthy, HIF-1 represents a promising target for novel cancer therapeutics. In this review, we summarize the molecular mechanisms underlying the interplay between HIF-1 and energetic metabolism, with a focus on mitochondria, of hypoxic cancer cells
Analysis of Co-Channel Coexistence Mitigation Methods Applied to IEEE 802.11p and 5G NR-V2X Sidelink
Direct communication between vehicles and surrounding objects, called vehicle-to-everything (V2X), is ready for the market and promises to raise the level of safety and comfort while driving. To this aim, specific bands have been reserved in some countries worldwide and different wireless technologies have been developed; however, these are not interoperable. Recently, the issue of co-channel coexistence has been raised, leading the European Telecommunications Standards Institute (ETSI) to propose a number of solutions, called mitigation methods, for the coexistence of the IEEE 802.11p based ITS-G5 and the 3GPP fourth generation (4G) long term evolution (LTE)-V2X sidelink. In this work, several of the envisioned alternatives are investigated when adapted to the coexistence of the IEEE 802.11p with its enhancement IEEE 802.11bd and the latest 3GPP standards, i.e., the fifth generation (5G) new radio (NR)-V2X. The results, obtained through an open-source simulator that is shared with the research community for the evaluation of additional proposals, show that the methods called A and C, which require modifications to the standards, improve the transmission range of one or both systems without affecting the other, at least in low-density scenarios
The effects of body exposure on self-body image and esthetic appreciation in anorexia nervosa.
Repeated exposures to thin-idealized body shapes may alter women's perceptions of what normal (e.g., accepted) and ideal (e.g., desired) bodies in a cultural environment look like. The aim of the present study was to investigate whether exposure to thin and round body shapes may change the subsequent esthetic appreciation of others' bodies and the perceptual and cognitive-affective dimensions of self-body image in patients suffering from anorexia nervosa (AN). Thirteen AN patients and 13 matched healthy controls were exposed to pictures of either thin or round unfamiliar body models and, before and after exposure, they were required to either express liking judgments about round and slim figures of unfamiliar bodies (esthetic task) or to adjust distorted pictures of their own body to their perceptual (How do you see yourself?), affective (How do you feel yourself?), metacognitive (How do others see you?) and ideal (How would you like to look like?) body image (self-body adjustment task). Brief exposures to round models increased liking judgments of round figures in both groups. However, only in AN patients, exposure to round models induced an increase in thin figures liking, which positively correlated with their preoccupation with dieting. Furthermore, exposure to round bodies in AN patients, but not in controls, increased the distortion for the perceptual body image and decreased the size of the ideal one. No differences between the two groups were obtained after adaptation to thin models. Our results suggest that AN patients' perception of their own and others' body is more easily malleable by exposure to round figures as compared to controls. Crucially, this mechanism may strongly contribute to the development and maintenance of self-body image disturbances
Performance Analysis of Sidelink 5G-V2X Mode 2 through an Open-Source Simulator
The Third Generation Partnership Project (3GPP) has recently published a new set of specifications to enable advanced driving applications in fifth generation (5G) vehicle-to-everything (V2X) scenarios, with particular effort dedicated to the sidelink resource allocation in the autonomous mode, named Mode 2. In this paper, we conduct a comprehensive analysis of Mode 2 performance via an open-source system-level simulator, which implements the 5G New Radio (NR) flexible numerology and physical layer aspects together with the newly specified sidelink resource allocation modes for V2X communications and different data traffic patterns. Results collected through extensive simulation campaigns, under a wide variety of vehicle density, data transmission settings and traffic patterns, showcase the effects of the new 5G-V2X features on the sidelink resource allocation performance and provide some insights into possible ways to further improve Mode 2 performance
Mentalizing subtypes in eating disorders: A latent profile analysis
Background: Mentalizing, the mental capacity to understand oneself and others in terms of mental states, has been found to be reduced in several mental disorders. Some studies have suggested that eating disorders (EDs) may also be associated with impairments in mentalizing. The aim of this work is to investigate the possible presence of mentalizing subtypes in a sample of patients with EDs. Method: A sample of patients with eating disorders (N = 157) completed a battery of measures assessing mentalization and related variables, including the Reflective Functioning Questionnaire (RFQ), the Difficulties in Emotion Regulation Strategies (DERS), the Interpersonal Reactivity Index (IRI). Clinicians rated patients in relation to imbalances in different dimensions of mentalization to prementalizing modes and attachment style by using the Mentalization Imbalances Scale, the Modes of Mentalization Scale (MMS), and the Adult Attachment Questionnaire. A latent profile analysis was conducted to test the possible presence of different subgroups. MANOVA was used to test the possible differences between the four mentalizing profiles in relation to emotion dysregulation (DERS), empathy (IRI), and adequate and impairments in mentalizing (MMS and RFQ). Results: The latent profile analysis suggested the presence of four different profiles in relation to impairments in the dimensions of mentalization: (1) affective/self/automatic imbalances, (2) external imbalance, (3) cognitive/self/automatic imbalances, and (4) cognitive/other/automatic imbalances. Patients belonging to profile 1 are characterized by the prevalence of affective mentalization that overwhelms the capacity to reflect on mental states with an imbalance on the self-dimension; profile 2 patients are excessively focused on the external cues of mentalization; profile 3 patients are characterized by an over-involvement on the cognitive and self-facets of mentalization, with an impairment in adopting the other mind perspective; and profile 4 patients have similar impairments compared to profile 3 patients but with an excessive focus on others and deficits in self-reflection. These profiles were heterogeneous in terms of EDs represented in each group and presented significant differences on various variables such as attachment style, emotion dysregulation, empathy, interpersonal reactivity, and reflective function. This study represents, so far, the first work that confirms the presence of different mentalizing patterns in ED patients. Conclusions: ED patients can be classified in relation to impairments in different dimensions of mentalization above and beyond ED diagnosis
The use of headspace solid-phase microextraction (HS-SPME) to assess the quality and stability of fruit products: an example using red mombin pulp (Spondias purpurea L.).
Magnetic and Electric Mie-Exciton Polaritons in Silicon Nanodisks
Light-matter interactions at the nanoscale constitute a fundamental
ingredient for engineering applications in nanophotonics and quantum optics. To
this regard electromagnetic Mie resonances excited in high-refractive index
dielectric nanoparticles have recently attracted interest because of their
lower losses and better control over the scattering patterns compared to their
plasmonic metallic counterparts. The emergence of several resonances in those
systems results in an overall high complexity, where the electric and magnetic
dipoles have significant overlap in the case of spherical symmetry, thus
concealing the contributions of each resonance separately. Here we show,
experimentally and theoretically, the emergence of strong light-matter coupling
between the magnetic and electric-dipole resonances of individual silicon
nanodisks coupled to a J-aggregated organic semiconductor resonating at optical
frequencies, evidencing how the different properties of the two resonances
results in two different coupling strengths. The energy splittings observed are
of the same order of magnitude as in similar plasmonic systems, thus confirming
dielectric nanoparticles as promising alternatives for localized strong
coupling studies. The coupling of both the electric and magnetic dipole
resonances can offer interesting possibilities for the control of directional
light scattering in the strong-coupling regime and the dynamic tuning of
nanoscale light-matter coupled states by external fields
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