169 research outputs found
Revealing Renewable Energy Perspectives via the Analysis of the Wholesale Electricity Market
The wholesale electricity and capacity market constitute the backbone of the Russian power industry. It is in this market that large suppliers and buyers operate, and its entire turnover is consequently transmitted to the retail market. Our paper presents a theoretical overview of the main tools for forming the cost of electricity and capacity in the wholesale market in Russia (depending on the regional affiliation), the type of end users, and the degree of state participation. We consider the specifics of the formation of the cost of electricity and capacity in the price and non-price wholesale markets of Russia, which differ in territorial, climatic, and economic characteristics, as well as the established structure of generation. In the empirical part of the paper, we carry out a structural analysis of the volumes of trade in electricity and capacity in the price and non-price zones of the market. Furthermore, we explain the reasons for the current dynamics of prices in the wholesale market. Using the obtained results, we calculate the maximum annual effect of the solar power plant operation in various zones of the Russian wholesale market, as well as in the retail market. In addition, we estimate the economic incentive for the transition of the functioning of power facilities from the wholesale to the retail market. Our results can be of considerable practical importance and might be used for improving the strategy for the development of the electric power industry at the regional level both in Russia and in the other countries. Β© 2022 by the authors. Licensee MDPI, Basel, Switzerland.This work was supported by a grant from the President of the Russian Federation (MK-4549.2021.2)
Scanning tunneling spectroscopy of high-temperature superconductors
Tunneling spectroscopy played a central role in the experimental verification
of the microscopic theory of superconductivity in the classical
superconductors. Initial attempts to apply the same approach to
high-temperature superconductors were hampered by various problems related to
the complexity of these materials. The use of scanning tunneling
microscopy/spectroscopy (STM/STS) on these compounds allowed to overcome the
main difficulties. This success motivated a rapidly growing scientific
community to apply this technique to high-temperature superconductors. This
paper reviews the experimental highlights obtained over the last decade. We
first recall the crucial efforts to gain control over the technique and to
obtain reproducible results. We then discuss how the STM/STS technique has
contributed to the study of some of the most unusual and remarkable properties
of high-temperature superconductors: the unusual large gap values and the
absence of scaling with the critical temperature; the pseudogap and its
relation to superconductivity; the unprecedented small size of the vortex cores
and its influence on vortex matter; the unexpected electronic properties of the
vortex cores; the combination of atomic resolution and spectroscopy leading to
the observation of periodic local density of states modulations in the
superconducting and pseudogap states, and in the vortex cores.Comment: To appear in RMP; 65 pages, 62 figure
Novel role for the innate immune receptor toll-like receptor 4 (TLR4) in the regulation of the wnt signaling pathway and photoreceptor apoptosis
Recent evidence has implicated innate immunity in regulating neuronal survival in the brain during stroke and other neurodegenerations. Photoreceptors are specialized light-detecting neurons in the retina that are essential for vision. In this study, we investigated the role of the innate immunity receptor TLR4 in photoreceptors. TLR4 activation by lipopolysaccharide (LPS) significantly reduced the survival of cultured mouse photoreceptors exposed to oxidative stress. With respect to mechanism, TLR4 suppressed Wnt signaling, decreased phosphorylation and activation of the Wnt receptor LRP6, and blocked the protective effect of the Wnt3a ligand. Paradoxically, TLR4 activation prior to oxidative injury protected photoreceptors, in a phenomenon known as preconditioning. Expression of TNFΞ± and its receptors TNFR1 and TNFR2 decreased during preconditioning, and preconditioning was mimicked by TNFΞ± antagonists, but was independent of Wnt signaling. Therefore, TLR4 is a novel regulator of photoreceptor survival that acts through the Wnt and TNFΞ± pathways. Β© 2012 Yi et al
Proteolytic cleavage of p53 mutants in response to mismatched DNA
Interaction of p53 with mismatched DNA induces proteolytic cleavage with release of a 35-kDa protein fragment from the p53βDNA complexes. The 35-kDa cleavage product is activated for specific biochemical function(s) and may play a role in the cellular response to DNA damage (Molinari et al (1996) Oncogene13: 2077β2086; Okorokov et al (1997) EMBO J16: 6008β6017). In the present study we have asked if mutants of p53 retain the ability to undergo similar proteolytic cleavage, and compared sequence-specific βDNA contactβ with βstructuralβ mutants commonly found in human cancer. In addition, a series of phosphorylation site mutants were generated to investigate the possible effects of phosphorylation/dephosphorylation on the proteolytic cleavage of p53. All mutants tested bound to a mismatched DNA target in vitro. Moreover, studies in vitro and in vivo indicate that p53 mutants with intact conformational structure (as determined by immunoreactivity with PAb246 and PAb1620) retain the ability to undergo proteolytic cleavage similar, if not identical, to the wild-type p53 protein. Our results suggest that the capacity for p53 to bind mismatched DNA is independent of structural conformation of the central core domain. Proteolytic cleavage, however, is crucially dependent upon a wild-type conformation of the protein. Β© 1999 Cancer Research Campaig
ASPP: a new family of oncogenes and tumour suppressor genes
The apoptosis stimulating proteins of p53 (ASPP) family consists of three members, ASPP1, ASPP2 and iASPP. They bind to proteins that are key players in controlling apoptosis (p53, Bcl-2 and RelA/p65) and cell growth (APCL, PP1). So far, the best-known function of the ASPP family members is their ability to regulate the apoptotic function of p53 and its family members, p63 and p73. Biochemical and genetic evidence has shown that ASPP1 and ASPP2 activate, whereas iASPP inhibits, the apoptotic but not the cell-cycle arrest function of p53. The p53 tumour suppressor gene, one of the most frequently mutated genes in human cancer, is capable of suppressing tumour growth through its ability to induce apoptosis or cell-cycle arrest. Thus, the ASPP family of proteins helps to determine how cells choose to die and may therefore be a novel target for cancer therapy
The irreversibility line of overdoped Bi_{2+x}Sr_{2-(x+y)}Cu_{1+y}O_{6 +- delta} at ultra-low temperatures and high magnetic fields
The irreversible magnetization of the layered high-T_{c} superconductor
Bi_{2+x}Sr_{2-(x+y)}Cu_{1+y}O_{6 +- delta} (Bi-2201) has been measured by means
of a capacitive torquemeter up to B=28 T and down to T=60 mK. No magnetization
jumps, peak effects or crossovers between different pinning mechanisms appear
to be present. The deduced irreversibility field B_{irr} can not be described
by the law B_{irr}(T)=B_{irr}(0)(1-T/T_{c})^n based on flux creep, but an
excellent agreement is found with the analytical form of the melting line of
the flux lattice as calculated from the Lindemann criterion. The behavior of
B_{irr}(T) obtained here is very similar to the resistive critical field of a
Bi-2201 thin film, suggesting that magnetoresistive experiments are likely to
be strongly influenced by flux lattice melting.Comment: 4 pages, 4 eps figure
Enhancement of endogenous neurogenesis in ephrin-B3 deficient mice after transient focal cerebral ischemia
Cerebral ischemia stimulates endogenous neurogenesis. However, the functional relevance of this phenomenon remains unclear because of poor survival and low neuronal differentiation rates of newborn cells. Therefore, further studies on mechanisms regulating neurogenesis under ischemic conditions are required, among which ephrin-ligands and ephrin-receptors (Eph) are an interesting target. Although Eph/ephrin proteins like ephrin-B3 are known to negatively regulate neurogenesis under physiological conditions, their role in cerebral ischemia is largely unknown. We therefore studied neurogenesis, brain injury and functional outcome in ephrin-B3β/β (knockout) and ephrin-B3+/+ (wild-type) mice submitted to cerebral ischemia. Induction of stroke resulted in enhanced cell proliferation and neuronal differentiation around the lesion site of ephrin-B3β/β compared to ephrin-B3+/+ mice. However, prominent post-ischemic neurogenesis in ephrin-B3β/β mice was accompanied by significantly increased ischemic injury and motor coordination deficits that persisted up to 4Β weeks. Ischemic injury in ephrin-B3β/β mice was associated with a caspase-3-dependent activation of the signal transducer and activator of transcription 1 (STAT1). Whereas inhibition of caspase-3 had no effect on brain injury in ephrin-B3+/+ animals, infarct size in ephrin-B3β/β mice was strongly reduced, suggesting that aggravated brain injury in these animals might involve a caspase-3-dependent activation of STAT1. In conclusion, post-ischemic neurogenesis in ephrin-B3β/β mice is strongly enhanced, but fails to contribute to functional recovery because of caspase-3-mediated aggravation of ischemic injury in these animals. Our results suggest that ephrin-B3 might be an interesting target for overcoming some of the limitations of further cell-based therapies in stroke
Promoter Complexity and Tissue-Specific Expression of Stress Response Components in Mytilus galloprovincialis, a Sessile Marine Invertebrate Species
The mechanisms of stress tolerance in sessile animals, such as molluscs, can offer fundamental insights into the adaptation of organisms for a wide range of environmental challenges. One of the best studied processes at the molecular level relevant to stress tolerance is the heat shock response in the genus Mytilus. We focus on the upstream region of Mytilus galloprovincialis Hsp90 genes and their structural and functional associations, using comparative genomics and network inference. Sequence comparison of this region provides novel evidence that the transcription of Hsp90 is regulated via a dense region of transcription factor binding sites, also containing a region with similarity to the Gamera family of LINE-like repetitive sequences and a genus-specific element of unknown function. Furthermore, we infer a set of gene networks from tissue-specific expression data, and specifically extract an Hsp class-associated network, with 174 genes and 2,226 associations, exhibiting a complex pattern of expression across multiple tissue types. Our results (i) suggest that the heat shock response in the genus Mytilus is regulated by an unexpectedly complex upstream region, and (ii) provide new directions for the use of the heat shock process as a biosensor system for environmental monitoring
Prevention of methamphetamine-induced microglial cell death by TNF-Ξ± and IL-6 through activation of the JAK-STAT pathway
<p><b>Abstract</b></p> <p><b>Background</b></p> <p>It is well known that methamphetamine (METH) is neurotoxic and recent studies have suggested the involvement of neuroinflammatory processes in brain dysfunction induced by misuse of this drug. Indeed, glial cells seem to be activated in response to METH, but its effects on microglial cells are not fully understood. Moreover, it has been shown that cytokines, which are normally released by activated microglia, may have a dual role in response to brain injury. This led us to study the toxic effect of METH on microglial cells by looking to cell death and alterations of tumor necrosis factor-alpha (TNF-Ξ±) and interleukine-6 (IL-6) systems, as well as the role played by these cytokines.</p> <p><b>Methods</b></p> <p>We used the N9 microglial cell line, and cell death and proliferation were evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling assay and incorporation of bromodeoxyuridine, respectively. The TNF-Ξ± and IL-6 content was quantified by enzyme-linked immunosorbent assay, and changes in TNF receptor 1, IL-6 receptor-alpha, Bax and Bcl-2 protein levels by western blotting. Immunocytochemistry analysis was also performed to evaluate alterations in microglial morphology and in the protein expression of phospho-signal transducer and activator of transcription 3 (pSTAT3).</p> <p><b>Results</b></p> <p>METH induced microglial cell death in a concentration-dependent manner (EC<sub>50</sub>β=β1βmM), and also led to significant morphological changes and decreased cell proliferation. Additionally, this drug increased TNF-Ξ± extracellular and intracellular levels, as well as its receptor protein levels at 1βh, whereas IL-6 and its receptor levels were increased at 24βh post-exposure. However, the endogenous proinflammatory cytokines did not contribute to METH-induced microglial cell death. On the other hand, exogenous low concentrations of TNF-Ξ± or IL-6 had a protective effect. Interestingly, we also verified that the anti-apoptotic role of TNF-Ξ± was mediated by activation of IL-6 signaling, specifically the janus kinase (JAK)-STAT3 pathway, which in turn induced down-regulation of the Bax/Bcl-2 ratio.</p> <p><b>Conclusions</b></p> <p>These findings show that TNF-Ξ± and IL-6 have a protective role against METH-induced microglial cell death via the IL-6 receptor, specifically through activation of the JAK-STAT3 pathway, with consequent changes in pro- and anti-apoptotic proteins.</p
- β¦