Search results for "General Physics"
showing 10 items of 13583 documents
Novel concept for stabilising a hydraulic circuit containing counterbalance valve and pressure compensated flow supply
2016
In this paper, a novel concept for stabilising a hydraulic system containing a counterbalance valve and a pressure compensated flow supply is presented. The concept utilizes a secondary circuit where a low-pass filtered value of the load pressure is generated and fed back to the compensator of the flow supply valve. The novel concept has been investigated theoretically and experimentally. A linear model has been developed to verify the improved stability conditions. The novel concept has been implemented on a single boom actuated by a cylinder. The results show that the pressure oscillations in an otherwise unstable system can be suppressed with the novel concept. This happens without any c…
Comparison of electropolishing behaviours of TSC, ALM and cast 316L stainless steel in H 3 PO 4 /H 2 SO 4
2017
Abstract In recent decades, new manufacturing processes have been developed such as Thermal Spray Coating (TSC) and Additive Layer Manufacturing (ALM), which reduce or avoid machining of parts with complex geometries. This study aims to develop an Electropolishing (EP) process for TSC and ALM 316L Stainless Steel (SS). EP is an anodic dissolution process currently used in industry to reduce surface roughness and obtain a bright and smooth finish. The EP mechanism was studied, in a mixture of H3PO4 and H2SO4, for TSC, ALM and “cast” SS in order to determine the best conditions (time, temperature, potential). Special attention was paid to surface characterization by combining several techniqu…
The regression Tsetlin machine: a novel approach to interpretable nonlinear regression
2019
Relying simply on bitwise operators, the recently introduced Tsetlin machine (TM) has provided competitive pattern classification accuracy in several benchmarks, including text understanding. In this paper, we introduce the regression Tsetlin machine (RTM), a new class of TMs designed for continuous input and output, targeting nonlinear regression problems. In all brevity, we convert continuous input into a binary representation based on thresholding, and transform the propositional formula formed by the TM into an aggregated continuous output. Our empirical comparison of the RTM with state-of-the-art regression techniques reveals either superior or on par performance on five datasets. Thi…
Phosphorylation of CENP-A on serine 7 does not control centromere function.
2019
CENP-A is the histone H3 variant necessary to specify the location of all eukaryotic centromeres via its CENP-A targeting domain and either one of its terminal regions. In humans, several post-translational modifications occur on CENP-A, but their role in centromere function remains controversial. One of these modifications of CENP-A, phosphorylation on serine 7, has been proposed to control centromere assembly and function. Here, using gene targeting at both endogenous CENP-A alleles and gene replacement in human cells, we demonstrate that a CENP-A variant that cannot be phosphorylated at serine 7 maintains correct CENP-C recruitment, faithful chromosome segregation and long-term cell viab…
Injury-activated glial cells promote wound healing of the adult skin in mice
2018
Cutaneous wound healing is a complex process that aims to re-establish the original structure of the skin and its functions. Among other disorders, peripheral neuropathies are known to severely impair wound healing capabilities of the skin, revealing the importance of skin innervation for proper repair. Here, we report that peripheral glia are crucially involved in this process. Using a mouse model of wound healing, combined with in vivo fate mapping, we show that injury activates peripheral glia by promoting de-differentiation, cell-cycle re-entry and dissemination of the cells into the wound bed. Moreover, injury-activated glia upregulate the expression of many secreted factors previously…
The genetic prehistory of the Baltic Sea region
2018
Correction: Nature communications 9 (2018), art. no. 1494 doi:10.1038/s41467-018-03872-y While the series of events that shaped the transition between foraging societies and food producers are well described for Central and Southern Europe, genetic evidence from Northern Europe surrounding the Baltic Sea is still sparse. Here, we report genome-wide DNA data from 38 ancient North Europeans ranging from similar to 9500 to 2200 years before present. Our analysis provides genetic evidence that hunter-gatherers settled Scandinavia via two routes. We reveal that the first Scandinavian farmers derive their ancestry from Anatolia 1000 years earlier than previously demonstrated. The range of Mesolit…
Mutant p53 induces Golgi tubulo-vesiculation driving a prometastatic secretome
2020
TP53 missense mutations leading to the expression of mutant p53 oncoproteins are frequent driver events during tumorigenesis. p53 mutants promote tumor growth, metastasis and chemoresistance by affecting fundamental cellular pathways and functions. Here, we demonstrate that p53 mutants modify structure and function of the Golgi apparatus, culminating in the increased release of a pro-malignant secretome by tumor cells and primary fibroblasts from patients with Li-Fraumeni cancer predisposition syndrome. Mechanistically, interacting with the hypoxia responsive factor HIF1α, mutant p53 induces the expression of miR-30d, which in turn causes tubulo-vesiculation of the Golgi apparatus, leading …
Reciprocal regulation of the Il9 locus by counteracting activities of transcription factors IRF1 and IRF4.
2017
The T helper 9 (Th9) cell transcriptional network is formed by an equilibrium of signals induced by cytokines and antigen presentation. Here we show that, within this network, two interferon regulatory factors (IRF), IRF1 and IRF4, display opposing effects on Th9 differentiation. IRF4 dose-dependently promotes, whereas IRF1 inhibits, IL-9 production. Likewise, IRF1 inhibits IL-9 production by human Th9 cells. IRF1 counteracts IRF4-driven Il9 promoter activity, and IRF1 and IRF4 have opposing function on activating histone modifications, thus modulating RNA polymerase II recruitment. IRF1 occupancy correlates with decreased IRF4 abundance, suggesting an IRF1-IRF4-binding competition at the I…
MYC-driven epigenetic reprogramming favors the onset of tumorigenesis by inducing a stem cell-like state
2018
Breast cancer consists of highly heterogeneous tumors, whose cell of origin and driver oncogenes are difficult to be uniquely defined. Here we report that MYC acts as tumor reprogramming factor in mammary epithelial cells by inducing an alternative epigenetic program, which triggers loss of cell identity and activation of oncogenic pathways. Overexpression of MYC induces transcriptional repression of lineage-specifying transcription factors, causing decommissioning of luminal-specific enhancers. MYC-driven dedifferentiation supports the onset of a stem cell-like state by inducing the activation of de novo enhancers, which drive the transcriptional activation of oncogenic pathways. Furthermo…
Few layer 2D pnictogens catalyze the alkylation of soft nucleophiles with esters
2019
Group 15 elements in zero oxidation state (P, As, Sb and Bi), also called pnictogens, are rarely used in catalysis due to the difficulties associated in preparing well–structured and stable materials. Here, we report on the synthesis of highly exfoliated, few layer 2D phosphorene and antimonene in zero oxidation state, suspended in an ionic liquid, with the native atoms ready to interact with external reagents while avoiding aerobic or aqueous decomposition pathways, and on their use as efficient catalysts for the alkylation of nucleophiles with esters. The few layer pnictogen material circumvents the extremely harsh reaction conditions associated to previous superacid–catalyzed alkylations…