Time domain system identification of unknown initial conditions

System identification is a method for using measured data to create or improve a mathematical model of the object being tested. From the measured data however, noise is noticed at the beginning of the response. One solution to avoid this noise problem is to skip the noisy data and then use the initial conditions as active parameters, to be found by using the system identification process. This paper describes the development of the equations for setting up the initial conditions as active parameters. The simulated data and response data from actual shear buildings were used to prove the accuracy of both the algorithm and the computer program, which include the initial conditions as active parameters. The numerical and experimental model analysis showed that the value of mass, stiffness and frequency were very reasonable and that the computed acceleration and measured acceleration matched very well.     

Mechanical, deformation and fracture behaviors of bulk metallic glass composites reinforced by spherical B2 particles

Ti_(45)Cu_(40)Ni_7Zr_5Sn_(2.5)Si_(0.5) alloys were prepared under various cooling rate conditions during solidification.The alloys exhibited different volume fractions of B2 particles with 0～40 vol%in an amorphous matrix.Monolithic bulk metallic glass of 1 mm diameter showed no macroscopic plasticity and exhibited the typical vein patterns in a maximum shear stress plane on the fracture surface.However,a bulk metallic glass composite containing the B2 particles revealed obvious plasticity(～5.6%)with a remarkable work-hardening behavior that resulted from a stress-induced martensitic transformation of the B2 particles.Moreover,the composite displayed the complicated fracture morphologies containing of three types of fracture features.Through detailed investigations on the microstructural evolution,mechanical,deformation and fracture characteristics,the influence of B2 particle on overall behavior of the TiCu-based bulk metallic glass composites was elucidated.     

Oxidation behavior of high-strength FeCrAl alloys in a high-temperature supercritical carbon dioxide environment

The oxidation behavior of three high-strength FeCrAl alloys was investigated in supercritical carbon dioxide environment at 650 ℃. After exposure for 500 h, the weight gains of the FeCrAl alloys gradually decreased with increasing Al content. The oxide scales are primarily composed of α-Al_2O_3 and spinel oxides. With increasing Al content, the amount of α-Al_2O_3 increases and the C content decreased in the oxide scale and sub-scale matrix.Moreover, larger(Nb,Mo)C carbides formed in the sub-scale matrix and their number decreased with the increase of Al content.     

Bacterial peptide deformylase inhibitor PMT analogs inhibit cancer cell growth by interacting with human peptide deformylase

Potent inhibitors of human peptide deformylase （HsPDF） were screened using known PMT analog inhibi- tors of bacterial peptide deformylase. Forty-three species of PMT analogs that are non-peptidyl bacterial PDF inhibitors like actinonin were selected using virtual screening GOLD. Ten species out of 43 that could bind to HsPDF were selected and their antitumor activities were tested. Among them, four species （PMT-172, PMT-173, PMT-199, and PMT-201） showed excellent growth inhibition of cancer cell in the MTT assay. HsPDF-PMT binding was confirmed through a 1H-CPMG-T2 filter NMR experiment leading to a significant change in peak intensity for PMT-172 and PMT-199. These results suggest that PMT analogs could possibly interact with HsPDF and be a novel anticancer drug candidate.     

Embodied Anomaly Resolution in Molecular Genetics: A Case Study of RNAi

Scientific anomalies are observations and facts that contradict current scientific theories and they are instrumental in scientific theory change. Philosophers of science have approached scientific theory change from different perspectives as Darden (Theory change in science: Strategies from Mendelian genetics, 1991) observes: Lakatos (In: Lakatos, Musgrave (eds) Criticism and the growth of knowledge, 1970) approaches it as a progressive “research programmes” consisting of incremental improvements (“monster barring” in Lakatos, Proofs and refutations: The logic of mathematical discovery, 1976), Kuhn (The structure of scientific revolutions, 1996) observes that changes in “paradigms” are instigated by a crisis from some anomaly, and Hanson (In: Feigl, Maxwell (eds) Current issues in the philosophy of science, 1961) proposes that discovery does not begin with hypothesis but with some “problematic phenomena requiring explanation”. Even though anomalies are important in all of these approaches to scientific theory change, there have been only few investigations into the specific role anomalies play in scientific theory change. Furthermore, much of these approaches focus on the theories themselves and not on how the scientists and their experiments bring about scientific change (Gooding, Experiment and the making of meaning: Human agency in scientific observation and experiment, 1990). To address these issues, this paper approaches scientific anomaly resolution from a meaning construction point of view. Conceptual integration theory (Fauconnier and Turner, Cogn Sci 22:133–187, 1996; The way we think: Conceptual blending and mind’s hidden complexities, 2002) from cognitive linguistics describes how one constructs meaning from various stimuli, such as text and diagrams, through conceptual integration or blending. The conceptual integration networks that describe the conceptual integration process characterize cognition that occurs unconsciously during meaning construction. These same networks are used to describe some of the cognition while resolving an anomaly in molecular genetics called RNA interference (RNAi) in a case study. The RNAi case study is a cognitive-historical reconstruction (Nersessian, In: Giere (ed) Cognitive models of science, 1992) that reconstructs how the RNAi anomaly was resolved. This reconstruction traces four relevant molecular genetics publications in describing the cognition necessary in accounting for how RNAi was resolved through strategies (Darden 1991), abductive reasoning (Peirce, In: Hartshorne, Weiss (eds) Collected papers, 1958), and experimental reasoning (Gooding 1990). The results of the case study show that experiments play a crucial role in formulating an explanation of the RNAi anomaly and the integration networks describe the experiments’ role. Furthermore, these results suggest that RNAi anomaly resolution is embodied. It is embodied in a sense that cognition described in the cognitive-historical reconstruction is experientially based.

Development of a hybrid scaffold and a bioreactor for cartilage regeneration

We developed a hybrid scaffold and a bioreactor for cartilage regeneration. The hybrid scaffold was developed as combination of two components： a biodegradable framework and hydrogel-containing chondrocytes. We performed the MTT cell proliferation assay to compare the proliferation and viability of chondrocytes on three types of scaffolds： an aiginate gel, the hybrid scaffold, and an alginate sponge. Cells were encapsulated in 2% agarose gel. The bioreactor consisted of a circulation system and a compression system. We performed dynamic cell culture on these agarose gels in the bioreactor for 3 days.     

Genome-wide survey of recurrent HBV integration in hepatocellular carcinoma

To survey hepatitis B virus (HBV) integration in liver cancer genomes, we conducted massively parallel sequencing of 81 HBV-positive and 7 HBV-negative hepatocellular carcinomas (HCCs) and adjacent normal tissues. We found that HBV integration is observed more frequently in the tumors (86.4%) than in adjacent liver tissues (30.7%). Copy-number variations (CNVs) were significantly increased at HBV breakpoint locations where chromosomal instability was likely induced. Approximately 40% of HBV breakpoints within the HBV genome were located within a 1,800-bp region where the viral enhancer, X gene and core gene are located. We also identified recurrent HBV integration events (in ≥ 4 HCCs) that were validated by RNA sequencing (RNA-seq) and Sanger sequencing at the known and putative cancer-related TERT, MLL4 and CCNE1 genes, which showed upregulated gene expression in tumor versus normal tissue. We also report evidence that suggests that the number of HBV integrations is associated with patient survival.     

Meta-analysis of genome-wide association studies identifies common variants associated with blood pressure variation in east Asians

We conducted a meta-analysis of genome-wide association studies of systolic (SBP) and diastolic (DBP) blood pressure in 19,608 subjects of east Asian ancestry from the AGEN-BP consortium followed up with de novo genotyping (n = 10,518) and further replication (n = 20,247) in east Asian samples. We identified genome-wide significant (P < 5 × 10(-8)) associations with SBP or DBP, which included variants at four new loci (ST7L-CAPZA1, FIGN-GRB14, ENPEP and NPR3) and a newly discovered variant near TBX3. Among the five newly discovered variants, we obtained significant replication in the independent samples for all of these loci except NPR3. We also confirmed seven loci previously identified in populations of European descent. Moreover, at 12q24.13 near ALDH2, we observed strong association signals (P = 7.9 × 10(-31) and P = 1.3 × 10(-35) for SBP and DBP, respectively) with ethnic specificity. These findings provide new insights into blood pressure regulation and potential targets for intervention.