361 research outputs found
Random Modeling and Control of Nonlinear Active Suspension
For a quarter car with nonlinear active suspension in rough road, the problem of random modeling and control is considered. According to the relative motion principle, the influence of rough road can be seen as that force is disturbed by the noise and a random model is constructed. By an appropriate transform, the model is transformed into a lower triangular system, which can be used as backstepping method. Then a controller is designed such that the mean square of the state converges to an arbitrarily small neighborhood of zero by tuning design parameters. The simulation results illustrate the effectiveness of the proposed scheme. Therefore, the active suspension system offers better riding comfort and vehicle handing to the passengers
Experimental Investigation on R245fa Throttling Devices under High Temperature
The experiments on mass flow rate characteristics of R245fa refrigerant flowing through throttling devices including seven capillary tubes and the electronic expansion valve were carried out under the high-temperature working conditions. By combining data analysis with flow correlations, the design basis that is applicable to R245fa throttling devices can be obtained. By comparing the experimental mass flow rate with that predicted by Jung Correlation and Kim Correlation, it can be concluded that root mean square deviations of two correlations are 3.2 % and 3.3%, respectively. The root mean square deviation for electronic expansion valve is 4.5%. The conclusions offer high-accuracy design basis for throttling devices selection of high-temperature heat pump systems using R245fa as refrigerant
Random Modeling and Control of Nonlinear Active Suspension
For a quarter car with nonlinear active suspension in rough road, the problem of random modeling and control is considered. According to the relative motion principle, the influence of rough road can be seen as that force is disturbed by the noise and a random model is constructed. By an appropriate transform, the model is transformed into a lower triangular system, which can be used as backstepping method. Then a controller is designed such that the mean square of the state converges to an arbitrarily small neighborhood of zero by tuning design parameters. The simulation results illustrate the effectiveness of the proposed scheme. Therefore, the active suspension system offers better riding comfort and vehicle handing to the passengers
Structures and Stabilities of Carbon Chain Clusters Influenced by Atomic Antimony
The C-C bond lengths of the linear magnetic neutral CnSb, CnSb+ cations and CnSb− anions are within 1.255–1.336 Å, which is typical for cumulene structures with moderately strong double-bonds. In this report, we found that the adiabatic ionization energy (IE) of CnSb decreased with n. When comparing the IE~n relationship of CnSb with that of pure Cn, we found that the latter exhibited a stair-step pattern (n ≥ 6), but the IE~n relationship of CnSb chains took the shape of a flat curve. The IEs of CnSb were lower than those of corresponding pure carbon chains. Different from pure carbon chains, the adiabatic electron affinity of CnSb does not exhibit a parity effect. There is an even-odd alternation for the incremental binding energies of the open chain CnSb (for n = 1–16) and CnSb+ (n = 1–10, when n > 10, the incremental binding energies of odd (n) chain of CnSb+ are larger than adjacent clusters). The difference in the incremental binding energies between the even and odd chains of both CnSb and pure Cn diminishes with the increase in n. The incremental binding energies for CnSb- anions do not exhibit a parity effect. For carbon chain clusters, the most favorable binding site of atomic antimony is the terminal carbon of the carbon cluster because the terminal carbon with a large spin density bonds in an unsaturated way. The C-Sb bond is a double bond with Wiberg bond index (WBI) between 1.41 and 2.13, which is obviously stronger for a carbon chain cluster with odd-number carbon atoms. The WBI of all C-C bonds was determined to be between 1.63 and 2.01, indicating the cumulene character of the carbon chain. Generally, the alteration of WBI and, in particular, the carbon chain cluster is consistent with the bond length alteration. However, the shorter C-C distance did not indicate a larger WBI. Rather than relying on the empirical comparison of bond distance, the WBI is a meaningful quantitative indicator for predicting the bonding strength in the carbon chain
Recommended from our members
Optical biopsy identification and grading of gliomas using label-free visible resonance Raman spectroscopy.
Glioma is one of the most refractory types of brain tumor. Accurate tumor boundary identification and complete resection of the tumor are essential for glioma removal during brain surgery. We present a method based on visible resonance Raman (VRR) spectroscopy to identify glioma margins and grades. A set of diagnostic spectral biomarkers features are presented based on tissue composition changes revealed by VRR. The Raman spectra include molecular vibrational fingerprints of carotenoids, tryptophan, amide I/II/III, proteins, and lipids. These basic in situ spectral biomarkers are used to identify the tissue from the interface between brain cancer and normal tissue and to evaluate glioma grades. The VRR spectra are also analyzed using principal component analysis for dimension reduction and feature detection and support vector machine for classification. The cross-validated sensitivity, specificity, and accuracy are found to be 100%, 96.3%, and 99.6% to distinguish glioma tissues from normal brain tissues, respectively. The area under the receiver operating characteristic curve for the classification is about 1.0. The accuracies to distinguish normal, low grade (grades I and II), and high grade (grades III and IV) gliomas are found to be 96.3%, 53.7%, and 84.1% for the three groups, respectively, along with a total accuracy of 75.1%. A set of criteria for differentiating normal human brain tissues from normal control tissues is proposed and used to identify brain cancer margins, yielding a diagnostic sensitivity of 100% and specificity of 71%. Our study demonstrates the potential of VRR as a label-free optical molecular histopathology method used for in situ boundary line judgment for brain surgery in the margins
Conservation of protein interaction between SAGE1 and INTS3 identified in 3 different types of primates
Objective·To investigate the evolution of sarcoma antigen 1 (SAGE1), a member of the cancer-testis antigen (CTA) family, in three representative primate species—Macaca mulatta (Rhesus), Callithrix jacchus (Marmoset), and Microcebus murinus (Mouse Lemur), as well as the conservation of its interaction with INTS3, a subunit of the integrator complex.Methods·The interaction between INTS3 and SAGE1 in these primates and the interaction between INTS3 and human SAGE1 mutants were first validated in HEK293T cells by using co-immunoprecipitation (Co-IP). Truncated proteins were then tagged with His-SUMO and GST, respectively, and expressed in Escherichia coli, followed by a series of purification steps to obtain the target proteins. Surface plasmon resonance (SPR) was used to measure the binding affinity of the target proteins, and size exclusion chromatography with multi-angle light scattering (SEC-MALS) was used to determine the stoichiometry of the complex. Additionally, molecular docking was employed to predict the binding model of the truncated SAGE1 and INTS3. Mutations were performed on human SAGE1 key interface residues to analyze their binding to INTS3 by Co-IP.Results·The interaction between the full-length human-derived INTS3 and the full-length SAGE1 from the three primate species was confirmed by Co-IP. Truncated proteins were purified through multiple steps of tandom chromatography. The dissociation constants of the three pairs of truncated INTS3-SAGE1 were measured via SPR, and the SEC-MALS results demonstrated that the binding ratio of INTS3-SAGE1 was 2∶1. Furthermore, molecular docking predicted a structural model of the truncated INTS3-SAGE1 complex and the binding interface was extensively constituted with hydrophobic contacts assisted by some hydrophilic interactions. The interaction between the mutant SAGE1 and INTS3 full-length protein was significantly weakened.Conclusion·There is a conserved interaction between INTS3 and SAGE1 across Rhesus, Marmoset, and Mouse lemur
Leveraging diverse cell-death related signature predicts the prognosis and immunotherapy response in renal clear cell carcinoma
BackgroundModulation of programmed cell death in tumor cells alters the tumor microenvironment and the influx of tumor-infiltrating lymphocytes, and the combination of its inducers and immune checkpoint inhibitors plays a synergistic role in enhancing antitumor effects.MethodsWe downloaded the data of clear cell renal cell carcinoma samples from The Cancer Genome Atlas and used a machine learning approach to build a new programmed cell death index (PCDI) through 13 programmed cell death-related genes. Based on PCDI, clinical features, tumor immune microenvironment, chemotherapy response and immunotherapy response were systematically analyzed.ResultsPCDI consists of eight programmed cell death-related genes (TBX3, BID, TCIRG1, IDUA, KDR, PYCARD, IFNG and LRRK2). PCDI is a reliable predictor of survival in clear cell renal cell carcinoma patients and has been validated in multiple external datasets. We found that the high PCDI group showed higher levels of immune cell infiltration and better response to immunotherapy compared to the low PCDI group, and PCDI can also be used for prognostic prediction in a variety of cancers other than clear cell renal cell carcinoma. In vitro experiments demonstrated that knockdown of IDUA inhibited the proliferation and migration of clear cell renal cell carcinoma.ConclusionsThe PCDI identified in this study provides valuable insights into the clinical management of clear cell renal cell carcinoma by accurately evaluating the prognosis of patients with clear cell renal carcinoma and identifying the patient population that would benefit from immunotherapy
Inhibition of Colon Cancer by Polyphenols from Whole Cranberry
The ability of cranberry fruit extracts to inhibit colon carcinogenesis is under investigation using a combination of in vitro and in vivo methods. Compounds isolated from cranberry fruit (Vaccinium macrocarpon) including oligomeric polyphenols known as proanthocyanidins (PACs) decreased the proliferation of HCT116 and HT-29 colon cancer cells, induced apoptosis and reduced the formation of tumor colonies. Treatment of HCT116 colon cancer cells with cranberry polyphenols produced changes in expression of genes and proteins associated with the MAPK pathway, confirmed by microarray analysis, quantitative (Q)-PCR and Western blotting. Based on cranberry\u27s effect in vitro, a feeding study was conducted using AOM/DSS mice, an inflammatory colon cancer model that mimics colitis. Mice were treated with AOM and DSS to induce inflammation-driven colon carcinogenesis, while receiving an AIN-93 diet containing whole cranberry powder, concentrated polar polyphenolic extract, nonpolar extract or no cranberry (control). After 20 weeks on the diet, mice were sacrificed and the tumors analyzed. The number and volume of tumors was significantly lower in the cranberry powder group compared to control; the polyphenolic extract group also showed a significant reduction in tumor volume, while the non-polar extract showed significant inhibition on the tumor number. Tissue analysis indicated that expression of proinflammatory cytokines IL-1 and IL-6 were greatly reduced, and mRNA levels of iNOS and COX-2 were also significantly decreased by different cranberry preparations. These studies demonstrate potential for dietary cranberry to inhibit colon carcinogenesis through decreased inflammation and proliferation
- …