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排序方式: 共有953条查询结果,搜索用时 15 毫秒
51.
Melania Gonzalez-Rodriguez Veronica Astillero-Lopez Patricia Villanueva-Anguita M. Eugenia Paya-Rodriguez Alicia Flores-Cuadrado Sandra Villar-Conde Isabel Ubeda-Banon Alino Martinez-Marcos Daniel Saiz-Sanchez 《International journal of molecular sciences》2021,22(16)
Alzheimer’s disease (AD) is the most prevalent neurodegenerative disease in the elderly. Progressive accumulation of insoluble isoforms of amyloid-β peptide (Aβ) and tau protein are the major neuropathologic hallmarks, and the loss of cholinergic pathways underlies cognitive deficits in patients. Recently, glial involvement has gained interest regarding its effect on preservation and impairment of brain integrity. The limbic system, including temporal lobe regions and the olfactory bulb, is particularly affected in the early stages. In the early 1980s, the reduced expression of the somatostatin neuropeptide was described in AD. However, over the last three decades, research on somatostatin in Alzheimer’s disease has been scarce in humans. Therefore, the aim of this study was to stereologically quantify the expression of somatostatin in the human hippocampus and olfactory bulb and analyze its spatial distribution with respect to that of Aβ and au neuropathologic proteins and astroglia. The results indicate that somatostatin-expressing cells are reduced by 50% in the hippocampus but are preserved in the olfactory bulb. Interestingly, the coexpression of somatostatin with the Aβ peptide is very common but not with the tau protein. Finally, the coexpression of somatostatin with astrocytes is rare, although their spatial distribution is very similar. Altogether, we can conclude that somatostatin expression is highly reduced in the human hippocampus, but not the olfactory bulb, and may play a role in Alzheimer’s disease pathogenesis. 相似文献
52.
Antonella Virgilio Daniela Benigno Annalisa Pecoraro Annapina Russo Giulia Russo Veronica Esposito Aldo Galeone 《International journal of molecular sciences》2021,22(13)
In this paper, we report our investigations on five analogues, prepared by replacing sequence thymidines with abasic sites (S) one at a time, in comparison to their natural counterpart in order to evaluate their antiproliferative potential and the involvement of the residues not belonging to the central core of stacked guanosines in biological activity. The collected NMR (Nuclear Magnetic Resonance), CD (Circular Dichroism), and PAGE (Polyacrylamide Gel Electrophoresis) data strongly suggest that all of them adopt G-quadruplex (G4) structures strictly similar to that of the parent aptamer with the ability to fold into a dimeric structure composed of two identical G-quadruplexes, each characterized by parallel strands, three all-anti-G-tetrads and four one-thymidine loops (one bulge and three propeller loops). Furthermore, their antiproliferative (MTT assay) and anti-motility (wound healing assay) properties against lung and colorectal cancer cells were tested. Although all of the oligodeoxynucleotides (ODNs) investigated here exhibited anti-proliferative activity, the unmodified T30175 aptamer showed the greatest effect on cell growth, suggesting that both its characteristic folding in dimeric form and its presence in the sequence of all thymidines are crucial elements for antiproliferative activity. This straightforward approach is suitable for understanding the critical requirements of the G-quadruplex structures that affect antiproliferative potential and suggests its application as a starting point to facilitate the reasonable development of G-quadruplexes with improved anticancer properties. T30175相似文献
53.
Justin Kurian Veronica Bohl Michael Behanan Sadia Mohsin Mohsin Khan 《International journal of molecular sciences》2021,22(13)
Metabolism has emerged as a regulator of core stem cell properties such as proliferation, survival, self-renewal, and multilineage potential. Metabolites serve as secondary messengers, fine-tuning signaling pathways in response to microenvironment alterations. Studies show a role for central metabolite acetyl-CoA in the regulation of chromatin state through changes in histone acetylation. Nevertheless, metabolic regulators of chromatin remodeling in cardiac cells in response to increasing biological age remains unknown. Previously, we identified novel cardiac-derived stem-like cells (CTSCs) that exhibit increased functional properties in the neonatal heart (nCTSC). These cells are linked to a unique metabolism which is altered with CTSC aging (aCTSC). Here, we present an in-depth, RNA-sequencing-based (RNA-Seq) bioinformatic with cluster analysis that details a distinct epigenome present in nCTSCs but not in aCTSCs. Gene Ontology (GO) and pathway enrichment reveal biological processes, including metabolism, gene regulation enriched in nCTSCs, and STRING analysis that identifies a network of genes related to acetyl-CoA that can potentially influence chromatin remodeling. Additional validation by Western blot and qRT-PCR shows increased acetyl-CoA signaling and histone acetylation in nCTSCs compared to aCTSCs. In conclusion, our data reveal that the link between metabolism and histone acetylation in cardiac cells is altered with the aging of the cardiac tissue. 相似文献
54.
Marcello Candelli Laura Franza Giulia Pignataro Veronica Ojetti Marcello Covino Andrea Piccioni Antonio Gasbarrini Francesco Franceschi 《International journal of molecular sciences》2021,22(12)
Lipopolysaccharides (LPSs) are bacterial surface glycolipids, produced by Gram-negative bacteria. LPS is known to determine acute inflammatory reactions, particularly in the context of sepsis. However, LPS can also trigger chronic inflammation. In this case, the source of LPS is not an external infection, but rather an increase in endogenous production, which is usually sustained by gut microbiota (GM), and LPS contained in food. The first site in which LPS can exert its inflammatory action is the gut: both GM and gut-associated lymphoid tissue (GALT) are influenced by LPS and shift towards an inflammatory pattern. The changes in GM and GALT induced by LPS are quite similar to the ones seen in IBD: GM loses diversity, while GALT T regulatory (Tregs) lymphocytes are reduced in number, with an increase in Th17 and Th1 lymphocytes. Additionally, the innate immune system is triggered, through the activation of toll-like receptor (TLR)-4, while the epithelium is directly damaged, further triggering inflammation. In this review, we will discuss the importance of the crosstalk between LPS, GM, and GALT, and discuss the possible implications. 相似文献
55.
Detailed TSCAP measurements on silicon P+N and N+P diodes confirm the existence of two acceptor levels of nickel lying 0.21 ± 0.01 and 0.41 ÷ 0.01 eV from the valence and conduction bands respectively. Concentration of these centers, their spatial distribution and behaviours after several annealing treatments are also presented. 相似文献
56.
Vittorio Sgrigna Francesco Altamura Simone Ascani Roberto Battiston Raffaele Bencardino Sandor Blasko Aurora Buzzi Marco Casolino Livio Conti Stefano Lucidi Mauro Minori Andrea Papi Piergiorgio Picozza Stefano Rossi Carlo Stagni David Zilpimiani 《Microgravity science and technology》2007,19(5-6):70-74
EGLE is a wide frequency band search- coil magnetometer designed and built at the Roma Tre University. It has been installed onboard the ISS by the Italian astronaut Roberto Vittori on April 25, 2005 within the LAZIO- EGLE experiment carried out during the ENEIDE Soyuz mission. The scope of the experiment is to test EGLE in space and to investigate geomagnetic field variations. The main applications of EGLE are the study of electromagnetic environment inside the ISS, the correlation of magnetic field data with particle fluxes detected by LAZIO particle detector, and the monitoring of ionospheric perturbations possibly caused by Earth seismic activity. Since continuous electromagnetic field measurements on board the ISS are important for diverse space applications, a magnetometer with a suitable design is requested. Appropriate solutions for these applications, which have been adopted by EGLE, are in particular the use of 1- Wire technology and the possibility to detect by means of a search- coil magnetometer a large portion of the ULF frequency band, usually measured by flux- gate probes. To investigate the topside ionosphere electromagnetic environment and stability of Van Allen radiation belts in relation with seismic and anthropogenic electromagnetic emissions, a specific satellite mission (the ESPERIA project) has been designed for the Italian Space Agency (ASI), and up to now a few instruments of its payload have been built and tested in space. One of them is exactly the EGLE search- coil magnetometer. The first magnetic observations performed by this instrument reveal to be promising and demand for a further and deeper analysis based on a longer time series of data. 相似文献
57.
Tilke A. T. Stapelmann C. Eller M. Bach K.-H. Hampp R. Lindsay R. Conti R. Wille W. Jaiswal R. Galiano M. Jain A. 《Semiconductor Manufacturing, IEEE Transactions on》2007,20(2):59-67
In the present work, a high aspect ratio process (HARP) using a new O3/TEOS based sub atmospheric chemical vapor deposition process was implemented as STI gapfill in sub-65-nm CMOS. Good gapfill performance up to aspect ratios greater than 10:1 was demonstrated. Since the HARP process does not attack the STI liner as compared to HDP, a variety of different STI liners can be implemented. By comparing HARP with HDP, the geometry dependence of nand p-FET performance due to STI stress is discussed 相似文献
58.
Design of an enhanced access point to optimize TCP performance in Wi-Fi hotspot networks 总被引:1,自引:0,他引:1
In the last years, the number of Wi-Fi hotspots at public venues has undergone a substantial growth, promoting the WLAN technologies
as the ubiquitous solution to provide high-speed wireless connectivity in public areas. However, the adoption of a random
access CSMA-based paradigm for the 802.11 MAC protocol makes difficult to ensure high throughput and a fair allocation of
radio resources in 802.11-based WLANs. In this paper we evaluate extensively via simulations the interaction between the flow
control mechanisms implemented at the TCP layer and the contention avoidance techniques used at the 802.11 MAC layer. We conducted
our study considering initially M wireless stations performing downloads from the Internet. From our results, we observed that the TCP downlink throughput
is not limited by the collision events, but by the inability of the MAC protocol to assign a higher chance of accessing the
channel to the base station. We propose a simple and easy to implement modification of the base station’s behavior with the
purpose of increasing the TCP throughput reducing useless MAC protocol overheads. With our scheme, the base station is allowed
to transmit periodically bursts of data frames towards the mobile hosts. We design a resource allocation protocol aimed at
maximizing the success probability of the uplink transmissions by dynamically adapting the burst length to the collision probability
estimated by the base station. By its design, our scheme is also beneficial to achieve a fairer allocation of the channel
bandwidth among the downlink and uplink flows, and among TCP and UDP flows. Simulation results confirm both the improvement
in the TCP downlink throughput and the reduction of system unfairness. 相似文献
59.
Ana C. Arias Jürgen Daniel Brent Krusor Steve Ready Veronica Sholin Robert Street 《Journal of the Society for Information Display》2007,15(7):485-490
Abstract— Methods used to deposit and integrate solution‐processed materials to fabricate TFT backplanes by ink‐jet printing are discussed. Thematerials studied allow the development of an all‐additive process in which materials are deposited only where their functionality is required. The metal layer and semiconductor are printed, and the solution‐processed dielectric is spin‐coated. Silver nanoparticles are used as gate and datametals, the semiconductor used is a polythiophene derivative (PQT‐12), and the gate dielectric is an epoxy‐based photopolymer. The maximum processing temperature used is 150°C, making the process compatible with flexible substrates. The ION/IOFF ratio was found to be about 105?106, and TFT mobilities of 0.04 cm2/V‐sec were obtained. The influence of surface treatments on the size and shape of printed features is presented. It is shown that coffee‐stain effects can be controlled with ink formulation and that devices show the expected pixel response. 相似文献
60.