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81.
PRO teolysis TA rgeting C himeras (PROTACs) promote the degradation, rather than inhibition, of a drug target as a mechanism for therapeutic treatment. Bifunctional PROTAC molecules allow simultaneous binding of both the target protein and an E3-Ubiquitin ligase, bringing the two proteins into close spatial proximity to allow ubiquitinylation and degradation of the target protein via the cell's endogenous protein degradation pathway. We utilized native mass spectrometry (MS) to study the ternary complexes promoted by the previously reported PROTAC GNE-987 between Brd4 bromodomains 1 and 2, and Von Hippel Lindeau E3-Ubiquitin Ligase. Native MS at high resolution allowed us to measure ternary complex formation as a function of PROTAC concentration to provide a measure of complex affinity and stability, whilst simultaneously measuring other intermediate protein species. Native MS provides a high-throughput, low sample consumption, direct screening method to measure ternary complexes for PROTAC development.  相似文献   
82.
Bilberry is a characteristic field layer species in the boreal forests and is an important forage plant for herbivores of the North European ecosystem. Bilberry leaves contain high levels of phenolic compounds, especially hydroxycinnamic acids, flavonols, catechins, and proanthocyanidins. We investigated the phenolic composition of bilberry leaves in two studies, one following foliar development in forest and open areas, and the other along a wide geographical gradient from south to north boreal forests in Finland. An analysis of bilberry leaves collected in open and forest areas showed that major phenolic changes appeared in the first stages of leaf development, but, most importantly, synthesis and accumulation of flavonoids was delayed in the forest compared to the high light sites. Sampling along a geographical gradient in the boreal zone indicated that leaves from higher latitudes and higher altitudes had greater soluble phenolic and flavonol levels, higher antioxidant capacity, and lower contents of chlorogenic acid derivatives. The ecological significance of the results is discussed.  相似文献   
83.
Fungal species of genus Sepedonium are rich sources of diverse secondary metabolites (e.g., alkaloids, peptaibols), which exhibit variable biological activities. Herein, two new peptaibols, named ampullosporin F (1) and ampullosporin G (2), together with five known compounds, ampullosporin A (3), peptaibolin (4), chrysosporide (5), c(Trp-Ser) (6) and c(Trp-Ala) (7), have been isolated from the culture of Sepedonium ampullosporum Damon strain KSH534. The structures of 1 and 2 were elucidated based on ESI-HRMSn experiments and intense 1D and 2D NMR analyses. The sequence of ampullosporin F (1) was determined to be Ac-Trp1-Ala2-Aib3-Aib4-Leu5-Aib6-Gln7-Aib8-Aib9-Aib10-GluOMe11-Leu12-Aib13-Gln14-Leuol15, while ampullosporin G (2) differs from 1 by exchanging the position of Gln7 with GluOMe11. Furthermore, the total synthesis of 1 and 2 was carried out on solid-phase to confirm the absolute configuration of all chiral amino acids as L. In addition, ampullosporin F (1) and G (2) showed significant antifungal activity against B. cinerea and P. infestans, but were inactive against S. tritici. Cell viability assays using human prostate (PC-3) and colorectal (HT-29) cancer cells confirmed potent anticancer activities of 1 and 2. Furthermore, a molecular docking study was performed in silico as an attempt to explain the structure-activity correlation of the characteristic ampullosporins (1–3).  相似文献   
84.
Up to 11% of pregnancies extend to post-term with adverse obstetric events linked to pregnancies over 42 weeks. Oxidative stress and senescence (cells stop growing and dividing by irreversibly arresting their cell cycle and gradually ageing) can result in diminished cell function. There are no detailed studies of placental cell senescence markers across a range of gestational ages, although increased levels have been linked to pre-eclampsia before full term. This study aimed to determine placental senescence and oxidative markers across a range of gestational ages in women with uncomplicated pregnancies and those with a diagnosis of pre-eclampsia. Placentae were obtained from 37 women with uncomplicated pregnancies of 37–42 weeks and from 13 cases of pre-eclampsia of 31+2–41+2 weeks. The expression of markers of senescence, oxidative stress, and antioxidant defence (tumour suppressor protein p16INK4a, kinase inhibitor p21, interleukin-6 (IL-6), NADPH oxidase 4 (NOX4), glutathione peroxidases 1, 3, and 4 (GPx1, GPx3, and GPx4), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1)) genes was measured (quantitative real-time PCR). Protein abundance of p16INK4a, IL-6, NOX4, 8-hydroxy-2′-deoxy-guanosine (8-OHdG), and PlGF was assessed by immunocytochemistry. Placental NOX4 protein was higher in post-term than term deliveries and further increased by pre-eclampsia (p < 0.05 for all). P21 expression was higher in post-term placentae (p = 0.012) and in pre-eclampsia (p = 0.04), compared to term. Placental P16INK4a protein expression was increased post-term, compared to term (p = 0.01). In normotensive women, gestational age at delivery was negatively associated with GPx4 and PlGF (mRNA and protein) (p < 0.05 for all), whereas a positive correlation was seen with placental P21, NOX4, and P16INK4a (p < 0.05 for all) expression. Markers of placental oxidative stress and senescence appear to increase as gestational age increases, with antioxidant defences diminishing concomitantly. These observations increase our understanding of placental health and may contribute to assessment of the optimal gestational age for delivery.  相似文献   
85.
Induced seismicity associated with Enhanced Geothermal Systems   总被引:2,自引:0,他引:2  
Enhanced Geothermal Systems (EGS) have the potential to make a significant contribution to the world energy inventory. One controversial issue associated with EGS, however, is the impact of induced seismicity or microseismicity, which has been the cause of delays and threatened cancellation of at least two EGS projects worldwide. Although microseismicity has in fact had few (or no) adverse physical effects on operations or on surrounding communities, there remains public concern over the amount and magnitude of the seismicity associated with current and future EGS operations. The primary objectives of this paper are to present an up-to-date review of what is already known about the seismicity induced during the creation and operation of EGS, and of the gaps in our knowledge that, once addressed, should lead to an improved understanding of the mechanisms generating the events. Several case histories also illustrate a number of technical and public acceptance issues. We conclude that EGS-induced seismicity need not pose a threat to the development of geothermal energy resources if site selection is carried out properly, community issues are handled adequately and operators understand the underlying mechanisms causing the events. Induced seismicity could indeed prove beneficial, in that it can be used to monitor the effectiveness of EGS operations and shed light on geothermal reservoir processes.  相似文献   
86.
A siphon turbine is a low-head, axial-flow hydropower device that can be installed across an impound structure, such as a weir. A laboratory-scale siphon turbine and generator system is built from both off-the-shelf components and bespoke components designed using well-documented guidance. This paper proposes a modelling method for the system, which allows performance to be assessed as a function of operating variables including head, electric load, runner speed and flow rate. An un-modified, commercially available propeller is used for the runner, whose blade geometry is defined within the model as a set of polynomials. This enables flow angles at any radial position on a blade to be determined as a function of the system operating point. Consequently, the impact of design changes on system performance can be quantified, such as part-load efficiency for example. Testing using the laboratory-scale system is conducted up to a maximum gross head of 0.25 m, to validate the component models and then to demonstrate that the final system model provides satisfactory agreement with experiments over the operational speed and head range. The model therefore permits rapid conceptual design to be carried out without the need for computationally intensive co-optimisation of components.  相似文献   
87.
Various studies have found that British girls' curriculum subject preferences and future aspirations have changed and diversified in recent years. Other work has suggested that girls educated in single-sex schools might have a different (perhaps less gender-stereotypical) experience of education in comparison with their contemporaries at co-educational schools. This article draws on a study of the preferences of girls in English single-sex schools to explore these issues of subject choice and occupational aspiration further. It is argued that, like girls in mixed-sex secondary schools, single-sex schoolgirls' subject preferences have become more diverse and less gender-stereotypical than was the case twenty years ago. But where single-sex schoolgirls might have been expected to rate maths and science more highly than their counterparts in mixed-sex schools, the reverse was the case. Our findings support the argument that girls are now significantly more academically focused and ambitious for their future occupations than they were twenty years ago. However, we argue that a gender dichotomy remains evident in the types of future occupation chosen by girls.  相似文献   
88.
Hypertriglyceridemia is an independent risk factor in the development of cardiovascular diseases, and we have previously reported that oral administration of a grape seed procyanidin extract (GSPE) drastically decreases plasma levels of triglycerides (TG) and apolipoprotein B (ApoB) in normolipidemic rats, with a concomitant induction in the hepatic expression of the nuclear receptor small heterodimer partner (NR0B2/SHP). Our objective in this study was to elucidate whether SHP is the mediator of the reduction of TG-rich ApoB-containing lipoproteins triggered by GSPE. We show that GSPE inhibited TG and ApoB secretion in human hepatocarcinoma HepG2 cells and had and hypotriglyceridemic effect in wild-type mouse. The TG-lowering action of GSPE was abolished in HepG2 cells transfected with a SHP-specific siRNA and in a SHP-null mouse. Moreover, in mouse liver, GSPE downregulated several lipogenic genes, including steroid response element binding protein 1c (SREBP-1c), and upregulated carnitine palmitoyltransferase-1A (CPT-1A) and apolipoprotein A5 (ApoA5), in a SHP-dependent manner. In HepG2 cells GSPE also inhibited ApoB secretion, but in a SHP-independent manner. In conclusion, SHP is a key mediator of the hypotriglyceridemic response triggered by GSPE. This novel signaling pathway of procyanidins through SHP may be relevant to explain the health effects ascribed to the regular consumption of dietary flavonoids.  相似文献   
89.
The combination of force and flexibility enables controlled and soft movements. In sharp contrast, presently used machines are solid and mostly based on stiff driveshafts or cog wheels. Magnetic elastomers are realized through dispersion of small particles in polymer matrices and have attracted significant interest as soft actuators for controlled movement or conveying and are particularly attractive candidates for magnetic pump applications. At present, low magnetic particle loading and thus limited actuator strength have restricted the application of such materials. Here, the direct incorporation of metal microparticles into a very soft and flexible silicone and its application as an ultra‐flexible, yet strong magnetic tube, is described. Because metals have a far higher saturation magnetization and higher density than oxides, the resulting increased force/volume ratio afforded significantly stronger magnetic actuators with high mechanical stability, flexibility, and shape memory. Elliptical inner diameter shape of the tubing allowed a very efficient contraction of the tube by applying an external magnetic field. The combination of magnetic silicone tubes and a magnetic field generating device results in a magnetic peristaltic pump.  相似文献   
90.
Partial Reconfiguration (PR) is a method for Field Programmable Gate Array (FPGA) designs which allows multiple applications to time-share a portion of an FPGA while the rest of the device continues to operate unaffected. Using this strategy, the physical layer processing architecture in Software Defined Radio (SDR) systems can benefit from reduced complexity and increased design flexibility, as different waveform applications can be grouped into one part of a single FPGA. Waveform switching often means not only changing functionality, but also changing the FPGA clock frequency. However, that is beyond the current functionality of PR processes as the clock components (such as Digital Clock Managers (DCMs)) are excluded from the process of partial reconfiguration. In this paper, we present a novel architecture that combines another reconfigurable technology, Dynamic Reconfigurable Port (DRP), with PR based on a single FPGA in order to dynamically change both functionality and also the clock frequency. The architecture is demonstrated to reduce hardware utilization significantly compared with standard, static FPGA design.  相似文献   
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