SciCombinator

Discover the most talked about and latest scientific content & concepts.

 

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Proteolysis in eukaryotic cells is mainly mediated by the ubiquitin (Ub)-proteasome system (UPS) and the autophagylysosome system (hereafter autophagy). The UPS is a selective proteolytic system in which substrates are recognized and tagged with ubiquitin for processive degradation by the proteasome. Autophagy is a bulk degradative system that uses lysosomal hydrolases to degrade proteins as well as various other cellular constituents. Since the inception of their discoveries, the UPS and autophagy were thought to be independent of each other in components, action mechanisms, and substrate selectivity. Recent studies suggest that cells operate a single proteolytic network comprising of the UPS and autophagy that share notable similarity in many aspects and functionally cooperate with each other to maintain proteostasis. In this review, we discuss the mechanisms underlying the crosstalk and interplay between the UPS and autophagy, with an emphasis on substrate selectivity and compensatory regulation under cellular stresses.

Concepts: DNA, Signal transduction, Enzyme, Organelle, Endoplasmic reticulum, Cytoplasm, Proteasome, Proteolysis

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We demonstrate a molecular-level observation of driving CO2 molecules into a quasi-condensed phase on the solid surface of metal nanoparticles (NP) under ambient conditions of 1 bar and 298 K. This is achieved via a CO2 accumulation in the interface between a metal-organic framework (MOF) and a metal NP surface formed by coating NPs with a MOF. Using real-time surface-enhanced Raman scattering spectroscopy, a >18-fold enhancement of surface coverage of CO2 is observed at the interface. The high surface concentration leads CO2 molecules to be in close proximity with the probe molecules on the metal surface (4-methylbenzenethiol), and transforms CO2 molecules into a bent conformation without the formation of chemical bonds. Such linear-to-bent transition of CO2 is unprecedented at ambient conditions in the absence of chemical bond formation, and is commonly observed only at pressurized systems (>105 bar). The molecular-level observation of a quasi-condensed phase induced by MOF coating could impact the future design of hybrid materials in diverse applications, including catalytic CO2 conversion and ambient solid-gas operation.

Concepts: Oxygen, Hydrogen, Molecule, Atom, Chemical bond, Carbon, Raman spectroscopy, Chemical compound

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Significant increase in energy density of batteries must be achieved by exploring new materials and cell configurations. Lithium metal and lithiated silicon are two promising high-capacity anode materials. Unfortunately, both these anodes require reliable passivating layer to survive the serious environmental corrosion during handling and cycling. Here we developed a surface fluorination process to form a homogeneous and dense LiF coating on reactive anode materials, with in situ generated fluorine gas by using a fluoropolymer, CYTOP, as the precursor. The process is effectively a “reaction in the beaker”, avoiding handling highly-toxic fluorine gas directly. For lithium metal, this LiF coating serves as a chemically stable and mechanically strong interphase, which minimizes the corrosion reaction with carbonate electrolytes and suppresses dendrite formation, enabling dendrite-free and stable cycling over 300 cycles with current densities up to 5 mA/cm2. Lithiated silicon can serve as either a prelithiation additive for existing lithium-ion batteries or a replacement for lithium metal in Li-O2 and Li-S batteries. However, lithiated silicon reacts vigorously with the standard slurry solvent N-methyl-2-pyrrolidinone (NMP), indicating it is not compatible with the real battery fabrication process. With the protection of crystalline and dense LiF coating, LixSi can be processed in anhydrous NMP with a high capacity of 2504 mAh/g. With low solubility of LiF in water, this protection layer also enables the stability of LixSi in humid air (~40% relative humidity). Therefore, this facile surface fluorination process brings huge benefit to both the existing lithium-ion batteries and next-generation lithium metal batteries.

Concepts: Oxygen, Density, Metal, Battery, Rechargeable battery, Lithium, Lithium battery, Passivation

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The objectives of this study were to examine differences in social participation among Veterans with spinal cord injuries/disorders with and without post-traumatic stress disorder, and determine if lower social participation was independently associated with having post-traumatic stress disorder.

Concepts: Mental disorder, Posttraumatic stress disorder, Stress, Spinal cord injury, United States Department of Veterans Affairs

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Isotretinoin is the most effective drug for acne with some side effects. Few studies exist regarding the effects of isotretinoin on hematological parameters with different results. Mostly, baseline values with a single value during or at the end of the treatment were compared. In this study, we aimed to determine the differences in hematological parameters during isotretinoin treatment until reaching the cumulative dose of 120 mg/kg.

Concepts: Acne vulgaris, Isotretinoin

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The abuse of 3, 4-methylenedioxymethamphetamine (MDMA), a psychedelic drug, can lead to a variety of disorders in neural system, including the death of retinal neural cells. MDMA at lower doses does not cause obvious cytotoxicity to photoreceptor cells, indicating potential indirect mechanisms which have not yet been elucidated. This study investigated the effect of MDMA at non-toxic concentration on macrophage activation state and its resultant toxicity to photoreceptor cells. Using a co-culture system, cytotoxicity was caused by MDMA on 661W cells after co-culturing with RAW264.7 macrophage. Results showed that MDMA induced the macrophages to M1 polarization, releasing more pro-inflammatory cytokines, upregulating the M1-related gene and protein expression. The phenotype, secretion pattern and cytotoxicity of the macrophages treated by MDMA are comparable to those of the ones stimulated by IFNγ and LPS. Our study demonstrated that MDMA promoted macrophage polarization to M1 and induced inflammatory response, providing the scientific rationale for the photoreceptor cell damage caused by the MDMA abuse.

Concepts: Gene, Cell, Cell biology, Apoptosis, Photoreceptor cell, Visual system, Cytotoxicity, Toxicity

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Intracellular compartmentalisation is a significant barrier to the successful nucleocytosolic delivery of biologics. The endocytic system has been shown to be responsible for compartmentalisation, providing an entry point, and trigger(s) for the activation of drug delivery systems. Consequently, many of the technologies used to understand endocytosis have found utility within the field of drug delivery. The use of fluorescent proteins as markers denoting compartmentalisation within the endocytic system has become commonplace. Several of the limitations associated with the use of green fluorescent protein (GFP) within the context of drug delivery have been explored here by asking a series of related questions: (1) Are molecules that regulate fusion to a specific compartment (i.e. Rab- or SNARE-GFP fusions) a good choice of marker for that compartment? (2) How reliable was GFP-marker overexpression when used to define a given endocytic compartment? (3) Can glutathione-s-transferase (GST) fused in frame with GFP (GST-GFP) act as a fluid phase endocytic probe? (4) Was GFP fluorescence a robust indicator of (GFP) protein integrity? This study concluded that there are many appropriate and useful applications for GFP; however, thought and an understanding of the biological and physicochemical character of these markers are required for the generation of meaningful data.

Concepts: Protein, Oxygen, Cell, Molecular biology, Cell membrane, Green fluorescent protein, Yellow fluorescent protein, Fusion power

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Head and Neck Surgery constantly has to oppose non-invasive organ preservation methods and therefore should be evaluated especially with regard to clinical and functional outcome. We will discuss the role of pharyngotomy in the treatment of HNSCC.

Concepts: Medicine, Head and neck anatomy, Head and neck, Cancer, Carcinoma, Squamous cell carcinoma, Squamous epithelium, Food preservation

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The influence of family on an individual’s fertility has long been an important topic of interest in fertility research. Although studies conducted mostly in developed countries found a significant bearing of fertility of the parents on the fertility of the children, there is a lack of formal research around this topic in India. The present study analyses the effect of sibling size of husband and wife on the completed family size of women using information of 5506 ever-married women aged 45-49 years incorporated in the India Human Development Survey-II (2011-2012). Inferential statistics, bivariate, Chi-square and Poisson regression were used as the methods of analysis. The unadjusted estimates of Poisson regression reveal sibling size of women (IRR: 1.02; p < 0.001) and husband (IRR: 1.01; p < 0.001) have a positive correlation with the completed family size of women. However, in the adjusted model, the effect of sibling size especially of husband diminishes gradually in the presence of socio-economic covariates of the women.

Concepts: Family, Regression analysis, Marriage, Husband, Mother, Sibling, Human Development Index, Wife