29 research outputs found

    Solvability of Nonlinear Integral Equations of Volterra Type

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    This paper deals with the existence of continuous bounded solutions for a rather general nonlinear integral equation of Volterra type and discusses also the existence and asymptotic stability of continuous bounded solutions for another nonlinear integral equation of Volterra type. The main tools used in the proofs are some techniques in analysis and the Darbo fixed point theorem via measures of noncompactness. The results obtained in this paper extend and improve essentially some known results in the recent literature. Two nontrivial examples that explain the generalizations and applications of our results are also included

    Strong Convergence of an Implicit -Iterative Process for Lipschitzian Hemicontractive Mappings

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    We establish the strong convergence for the implicit -iterative process associated with Lipschitzian hemicontractive mappings in Hilbert spaces

    3,3′-Dimethyl-1,1′-[2,2′-bipyridine-5,5′-diylbis(methyl­ene)]diimidazol-3-ium bis­(hexa­fluoro­phosphate)

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    The title compound, C20H22N6 2+·2PF6 −, was prepared by the reaction of 5,5′-bis­(bromo­meth­yl)-2,2′-bipyridine with 1-methyl­imidazole. The main mol­ecule lies on an inversion center located at the mid-point of the C—C bond joining the two pyridine rings. The asymmetric unit therefore contains one half-mol­ecule and one hexa­fluoro­phosphate anion. The dihedral angle between the pyridine and imidazole rings is 76.93 (7)°. In the crystal, weak inter­molecular C—H⋯F hydrogen bonds contribute to the stabilization of the packing

    Some Fixed Point Theorems for Nonlinear Set-Valued Contractive Mappings

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    Four fixed point theorems for nonlinear set-valued contractive mappings in complete metric spaces are proved. The results presented in this paper are extensions of a few well-known fixed point theorems. Two examples are also provided to illustrate our results

    Existence and Iterative Algorithms of Positive Solutions for a Higher Order Nonlinear Neutral Delay Differential Equation

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    This paper is concerned with the higher order nonlinear neutral delay differential equation [a(t)(x(t)+b(t)x(t-τ))(m)](n-m)+[h(t,x(h1(t)),…,x(hl(t)))](i)+f(t,x(f1(t)),…,x(fl(t)))=g(t), for all t≥t0. Using the Banach fixed point theorem, we establish the existence results of uncountably many positive solutions for the equation, construct Mann iterative sequences for approximating these positive solutions, and discuss error estimates between the approximate solutions and the positive solutions. Nine examples are included to dwell upon the importance and advantages of our results

    Epigenetic Changes in Neurodegenerative Diseases

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    Afflicted neurons in various neurodegenerative diseases generally display diverse and complex pathological features before catastrophic occurrence of massive neuronal loss at the late stages of the diseases. This complex nature of neuronal pathophysiology inevitably implicates systemwide changes in basic cellular activities such as transcriptional controls and signal cascades, and so on, as a cause. Recently, as one of these systemwide cellular changes associated with neurodegenerative diseases, epigenetic changes caused by protein toxicity have begun to be highlighted. Notably, recent advances in related techniques including next-generation sequencing (NGS) and mass spectrometry enable us to monitor changes in the post-translational modifications (PTMs) of histone proteins and to link these changes in histone PTMs to the specific transcriptional changes. Indeed, epigenetic alterations and consequent changes in neuronal transcriptome are now begun to be extensively studied in neurodegenerative diseases including Alzheimer’s disease (AD). In this review, we will discuss details of our current understandings on epigenetic changes associated with two representative neurodegenerative diseases [AD and polyglutamine (polyQ) diseases] and further discuss possible future development of pharmaceutical treatment of the diseases through modulating these epigenetic changes. © The Korean Society for Molecular and Cellular Biology. All rights reserved.1

    The GATA factor elt-1 regulates C. elegans developmental timing by promoting expression of the let-7 family microRNAs.

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    Postembryonic development in Caenorhabditis elegans is a powerful model for the study of the temporal regulation of development and for the roles of microRNAs in controlling gene expression. Stable switch-like changes in gene expression occur during development as stage-specific microRNAs are expressed and subsequently down-regulate other stage-specific factors, driving developmental progression. Key genes in this regulatory network are phylogenetically conserved and include the post-transcriptional microRNA repressor LIN-28; the nuclear hormone receptor DAF-12; and the microRNAs LIN-4, LET-7, and the three LET-7 family miRNAs (miR-48, miR-84, and miR-241). DAF-12 is known to regulate transcription of miR-48, miR-84 and miR-241, but its contribution is insufficient to account for all of the transcriptional regulation implied by the mutant phenotypes. In this work, the GATA-family transcription factor ELT-1 is identified from a genetic enhancer screen as a regulator of developmental timing in parallel to DAF-12, and is shown to do so by promoting the expression of the LET-7, miR-48, miR-84, and miR-241 microRNAs. The role of ELT-1 in developmental timing is shown to be separate from its role in cell-fate maintenance during post-embryonic development. In addition, analysis of Chromatin Immnoprecipitation (ChIP) data from the modENCODE project and this work suggest that the contribution of ELT-1 to the control of let-7 family microRNA expression is likely through direct transcription regulation

    Magnetic nanoparticles for ferroptosis cancer therapy with diagnostic imaging

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    Ferroptosis offers a novel method for overcoming therapeutic resistance of cancers to conventional cancer treatment regimens. Its effective use as a cancer therapy requires a precisely targeted approach, which can be facilitated by using nanoparticles and nanomedicine, and their use to enhance ferroptosis is indeed a growing area of research. While a few review papers have been published on iron-dependent mechanism and inducers of ferroptosis cancer therapy that partly covers ferroptosis nanoparticles, there is a need for a comprehensive review focusing on the design of magnetic nanoparticles that can typically supply iron ions to promote ferroptosis and simultaneously enable targeted ferroptosis cancer nanomedicine. Furthermore, magnetic nanoparticles can locally induce ferroptosis and combinational ferroptosis with diagnostic magnetic resonance imaging (MRI). The use of remotely controllable magnetic nanocarriers can offer highly effective localized image-guided ferroptosis cancer nanomedicine. Here, recent developments in magnetically manipulable nanocarriers for ferroptosis cancer nanomedicine with medical imaging are summarized. This review also highlights the advantages of current state-of-the-art image-guided ferroptosis cancer nanomedicine. Finally, image guided combinational ferroptosis cancer therapy with conventional apoptosis-based therapy that enables synergistic tumor therapy is discussed for clinical translations

    Allele-Specific Suppressors of lin-1(R175Opal) Identify Functions of MOC-3 and DPH-3 in tRNA Modification Complexes in Caenorhabditis elegans

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    The elongator (ELP) complex consisting of Elp1-6p has been indicated to play roles in multiple cellular processes. In yeast, the ELP complex has been shown to genetically interact with Uba4p/Urm1p and Kti11-13p for a function in tRNA modification. Through a Caenorhabditis elegans genetic suppressor screen and positional cloning, we discovered that loss-of-function mutations of moc-3 and dph-3, orthologs of the yeast UBA4 and KTI11, respectively, effectively suppress the Multivulva (Muv) phenotype of the lin-1(e1275, R175Opal) mutation. These mutations do not suppress the Muv phenotype caused by other lin-1 alleles or by gain-of-function alleles of ras or raf that act upstream of lin-1. The suppression can also be reverted by RNA interference of lin-1. Furthermore, we showed that dph-3(lf) also suppressed the defect of lin-1(e1275) in promoting the expression of a downstream target (egl-17). These results indicate that suppression by the moc-3 and dph-3 mutations is due to the elevated activity of lin-1(e1275) itself rather than the altered activity of a factor downstream of lin-1. We further showed that loss-of-function mutations of urm-1 and elpc-1-4, the worm counterparts of URM1 and ELP complex components in yeast, also suppressed lin-1(e1275). We also confirmed that moc-3(lf) and dph-3(lf) have defects in tRNA modifications as do the mutants of their yeast orthologs. These results, together with the observation of a likely readthrough product from a lin-1(e1275)∷gfp fusion transgene indicate that the aberrant tRNA modification led to failed recognition of a premature stop codon in lin-1(e1275). Our genetic data suggest that the functional interaction of moc-3/urm-1 and dph-3 with the ELP complex is an evolutionarily conserved mechanism involved in tRNA functions that are important for accurate translation

    BOSS: Bandwidth-optimized search accelerator for storage-class memory

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    © 2021 IEEE.Search is one of the most popular and important web services. The inverted index is the standard data structure adopted by most full-text search engines. Recently, custom hardware accelerators for inverted index search have emerged to demonstrate much higher throughput than the conventional CPU or GPU. However, less attention has been paid to addressing the memory capacity pressure with inverted index. The conventional DDRx DRAM memory system significantly increases the system cost to make a terabyte-scale main memory. Instead, a shared memory pool composed of storage-class memory (SCM) devices is a promising alternative for scaling memory capacity at a much lower cost. However, this SCM-based pooled memory poses new challenges caused by the limited bandwidth of both SCM devices and the shared interconnect to the host CPU. Thus, we propose BOSS, the first near-data processing (NDP) architecture for inverted index search on SCM-based pooled memory, which maintains high throughput of query processing in this bandwidth- constrained environment. BOSS mitigates the impact of low bandwidth of SCM devices by employing early-termination search algorithms, reducing the footprint of intermediate data, and introducing a programmable decompression module that can select the best compression scheme for a given inverted index. Furthermore, BOSS includes a top-k selection module in hardware to substantially reduce the host-accelerator bandwidth consumption. Compared to Apache Lucene, a production-grade search engine library, running on 8 CPU cores, BOSS achieves a geomean speedup of 8.1× on various complex query types, while reducing the average energy consumption by 189×.N
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