An adaptive polynomial based forward prediction algorithm for multi-actuator real-time dynamic substructuring

Real-time dynamic substructuring is a novel experimental technique used to test the dynamic behaviour of complex structures. The technique involves creating a hybrid model of the entire structure by combining an experimental test piece—the substructure—with a set of numerical models. In this paper we describe a multi-actuator substructured system of a coupled three mass–spring–damper system and use this to demonstrate the nature of delay errors which can first lead to a loss of accuracy and then to instability of the substructuring algorithm. Synchronization theory and delay compensation are used to show how the delay errors, present in the transfer systems, can be minimized by online forward prediction. This new algorithm uses a more generic approach than the single step algorithms applied to substructuring thus far, giving considerable advantages in terms of flexibility and accuracy. The basic algorithm is then extended by closing the control loop resulting in an error driven adaptive feedback controller which can operate with no prior knowledge of the plant dynamics. The adaptive algorithm is then used to perform a real substructuring test using experimentally measured forces to deliver a stable substructuring algorithm

Cancer experience in the relatives of an unselected series of breast cancer patients

First- and second-degree relatives of an unselected series of 402 breast cancer patients have been studied for their cancer experience. In the first-degree relatives an excess of all cancers is seen [overall relative risk (RR) = 1.28, P = 0.002; males RR = 1.26, P = 0.047; females RR = 1.30, P = 0.022). There is a marked excess of sarcoma (RR = 4.26, P = 0.0064); females are at high risk of breast cancer (RR = 2.68, P < 0.0001) and males have an excess of carcinoma of the lip, oral cavity and pharynx (RR = 4.22, P = 0.0032). Second-degree relatives have a non-significant excess of all cancers (RR = 1.14, P = 0.14); females have a borderline excess of breast cancer (RR = 1.53, P = 0.08) and an excess of carcinoma of the kidney (RR = 7.46, P = 0.0012) and males have an excess of carcinoma of the trachea and lung (RR = 1.50, P = 0.032). No excess of prostate or ovarian carcinoma was seen. Relatives are at slightly higher risk if the index patient is diagnosed between the ages of 40 and 49 (first-degree RR = 1.64, P = 0.007; second-degree RR = 1.43, P = 0.02). The excess of cancers, including breast cancers, is not limited to a few high-risk families, but appears to be spread across many. These observations may be accounted for by shared environmental factors within families or a common predisposing gene with low penetrance

Spin resonance of 2D electrons in a large-area silicon MOSFET

We report electron spin resonance (ESR) measurements on a large-area silicon MOSFET. An ESR signal at g-factor 1.9999(1), and with a linewidth of 0.6 G, is observed and found to arise from two-dimensional (2D) electrons at the Si/SiO2 interface. The signal and its intensity show a pronounced dependence on applied gate voltage. At gate voltages below the threshold of the MOSFET, the signal is from weakly confined, isolated electrons as evidenced by the Curie-like temperature dependence of its intensity. The situation above threshold appears more complicated. These large-area MOSFETs provide the capability to controllably tune from insulating to conducting regimes by adjusting the gate voltage while monitoring the state of the 2D electron spins spectroscopically.Comment: 7 pages, 3 figures, submitted to Physica E special edition for EPS2DS-1

Causality in real-time dynamic substructure testing

Causality, in the bond graph sense, is shown to provide a conceptual framework for the design of real-time dynamic substructure testing experiments. In particular, known stability problems with split-inertia substructured systems are reinterpreted as causality issues within the new conceptual framework. As an example, causality analysis is used to provide a practical solution to a split-inertia substructuring problem and the solution is experimentally verified

Artificial intelligence for the management of pancreatic diseases

Novel artificial intelligence techniques are emerging in all fields of healthcare, including gastroenterology. The aim of this review is to give an overview of artificial intelligence applications in the management of pancreatic diseases. We performed a systematic literature search in PubMed and Medline up to May 2020 to identify relevant articles. Our results showed that the development of machine-learning based applications is rapidly evolving in the management of pancreatic diseases, guiding precision medicine in clinical, endoscopic and radiologic settings. Before implementation into clinical practice, further research should focus on the external validation of novel techniques, clarifying the accuracy and robustness of these models.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Induced magnetic moment of Eu3+ ions in GaN

Magnetic semiconductors with coupled magnetic and electronic properties are of high technological and fundamental importance. Rare-earth elements can be used to introduce magnetic moments associated with the uncompensated spin of 4f-electrons into the semiconductor hosts. The luminescence produced by rare-earth doped semiconductors also attracts considerable interest due to the possibility of electrical excitation of characteristic sharp emission lines from intra 4f-shell transitions. Recently, electroluminescence of Eu-doped GaN in current-injection mode was demonstrated in p-n junction diode structures grown by organometallic vapour phase epitaxy. Unlike most other trivalent rare-earth ions, Eu3+ ions possess no magnetic moment in the ground state. Here we report the detection of an induced magnetic moment of Eu3+ ions in GaN which is associated with the 7F2 final state of 5D0→7F2 optical transitions emitting at 622 nm. The prospect of controlling magnetic moments electrically or optically will lead to the development of novel magneto-optic devices

Bond graph based control and substructuring

A bond graph framework giving a unified treatment of both physical-model based control and hybrid experimental–numerical simulation (also known as real-time dynamic substructuring) is presented. The framework consists of two subsystems, one physical and one numerical, connected by a transfer system representing non-ideal actuators and sensors. Within this context, a two-stage design procedure is proposed: firstly, design and/or analysis of the numerical and physical subsystem interconnection as if the transfer system were not present; and secondly removal of as much as possible of the transfer system dynamics while having regard for the stability margins established in the first stage. The approach allows the use of engineering insight backed up by well-established control theory; a number of possibilities for each stage are given. The approach is illustrated using two laboratory systems: an experimental mass-spring-damper substructured system and swing up and hold control of an inverted pendulum. Experimental results are provided in the latter case

Prevalence, features, and explanations of missed and misinterpreted pancreatic cancer on imaging: a matched case-control study

Purpose To characterize the prevalence of missed pancreatic masses and pancreatic ductal adenocarcinoma (PDAC)-related findings on CT and MRI between pre-diagnostic patients and healthy individuals.Materials and methods Patients diagnosed with PDAC (2010-2016) were retrospectively reviewed for abdominal CT- or MRI-examinations 1 month-3 years prior to their diagnosis, and subsequently matched to controls in a 1:4 ratio. Two blinded radiologists scored each imaging exam on the presence of a pancreatic mass and secondary features of PDAC. Additionally, original radiology reports were graded based on the revised RADPEER criteria.Results The cohort of 595 PDAC patients contained 60 patients with a pre-diagnostic CT and 27 with an MRI. A pancreatic mass was suspected in hindsight on CT in 51.7% and 50% of cases and in 1.3% and 0.9% of controls by reviewer 1 (p < .001) and reviewer 2 (p < .001), respectively. On MRI, a mass was suspected in 70.4% and 55.6% of cases and 2.9% and 0% of the controls by reviewer 1 (p < .001) and reviewer 2 (p < .001), respectively. Pancreatic duct dilation, duct interruption, focal atrophy, and features of acute pancreatitis is strongly associated with PDAC (p < .001). In cases, a RADPEER-score of 2 or 3 was assigned to 56.3% of the CT-reports and 71.4% of MRI-reports.Conclusion Radiological features as pancreatic duct dilation and interruption, and focal atrophy are common first signs of PDAC and are often missed or unrecognized. Further investigation with dedicated pancreas imaging is warranted in patients with PDAC-related radiological findings.Cellular mechanisms in basic and clinical gastroenterology and hepatolog

Opto-mechanical measurement of micro-trap via nonlinear cavity enhanced Raman scattering spectrum

High-gain resonant nonlinear Raman scattering on trapped cold atoms within a high-fineness ring optical cavity is simply explained under a nonlinear opto-mechanical mechanism, and a proposal using it to detect frequency of micro-trap on atom chip is presented. The enhancement of scattering spectrum is due to a coherent Raman conversion between two different cavity modes mediated by collective vibrations of atoms through nonlinear opto-mechanical couplings. The physical conditions of this technique are roughly estimated on Rubidium atoms, and a simple quantum analysis as well as a multi-body semiclassical simulation on this nonlinear Raman process is conducted.Comment: 7 pages, 2 figure