Damping control of polodes, inertia and natural frequencies: Theory and application to automotive suspensions

This paper shows how tunable dampers can help control the instant centre of rotation of a 2D rigid body and its polode in planar motion, which in turn implies that the inertia tensor can also be controlled. For mechanisms equipped with some elasticity the results show that damping can also control their natural frequencies. The foundation of a general theory to control the polode is presented, exploring the chance of an optimal control formulation of the problem via a variational control principle, approached by the LQR (Linear Quadratic Regulator) method, after a suitable linearization. Application to automotive suspension linkages is presented that demonstrates the control of the instant roll centre and axis and consequently its instant roll vibration frequency to optimize the response, when excited by lateral inertia forces

Controlling complex networks: How much energy is needed?

The outstanding problem of controlling complex networks is relevant to many areas of science and engineering, and has the potential to generate technological breakthroughs as well. We address the physically important issue of the energy required for achieving control by deriving and validating scaling laws for the lower and upper energy bounds. These bounds represent a reasonable estimate of the energy cost associated with control, and provide a step forward from the current research on controllability toward ultimate control of complex networked dynamical systems.Comment: 4 pages paper + 5 pages supplement. accepted for publication in Physical Review Letters; http://link.aps.org/doi/10.1103/PhysRevLett.108.21870

Realization of a Single-Phase Multilevel Inverter for Grid-Connected Photovoltaic System

This paper introduces the implementation of a single-phase multilevel inverter for a grid-connected photovoltaic system. The considered topology contains a full bridge converter tied to an auxiliary circuit made of two power switches. A proportional integral (PI) current controller is established with this inverter to inject a sinusoidal current into the grid with a power factor near to unity. The studied system is tested on Matlab/Simulink and verified by experiment through a test bench comprising of a fabricated prototype and a DSP TMS320F28379D. The obtained results prove the efficiency of the inverter to maintain a direct power flow from DC sources, such as solar panels, to the grid by respecting some normalized criteria for this operation

Soft-tissue metastasis revealing a pancreatic adenocarcinoma: One case report and a review of literature

Soft tissue metastases from pancreatic adenocarcinoma are rare lesions and can be the source of diagnostic confusion both clinically and pathologically. To our knowledge, one patient has been reported on with soft tissue lesions that ultimately disclose a pancreatic adenocarcinoma. We report here on a patient who presented with a metastatic soft tissue lesion in the trochanter, and the buttocks, as the initial manifestation of pancreatic adenocarcinoma. Soft tissue metastasis from pancreatic carcinoma is a rare finding. Clinicians should be aware that metastatic soft tissue lesions could be the initial presenting sign for pancreatic cancer. Also, the immunohistochemical staining for CK 7 and 19 may be helpful for the diagnosis of metastatic pancreatic adenocarcinoma

COVID-19 Models for Hospital Surge Capacity Planning: A Systematic Review

Objective: Health system preparedness for coronavirus disease (COVID-19) includes projecting the number and timing of cases requiring various types of treatment. Several tools were developed to assist in this planning process. This review highlights models that project both caseload and hospital capacity requirements over time. Methods: We systematically reviewed the medical and engineering literature according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We completed searches using PubMed, EMBASE, ISI Web of Science, Google Scholar, and the Google search engine. Results: The search strategy identified 690 articles. For a detailed review, we selected 6 models that met our predefined criteria. Half of the models did not include age-stratified parameters, and only 1 included the option to represent a second wave. Hospital patient flow was simplified in all models; however, some considered more complex patient pathways. One model included fatality ratios with length of stay (LOS) adjustments for survivors versus those who die, and accommodated different LOS for critical care patients with or without a ventilator. Conclusion: The results of our study provide information to physicians, hospital administrators, emergency response personnel, and governmental agencies on available models for preparing scenario-based plans for responding to the COVID-19 or similar type of outbreak

Monte carlo estimation of electron contamination in a 18 MV clinical photon beam

Background: The electron contamination may reduce or even diminish the skin sparing property of the megavoltage beam. The detailed characteristics of contaminant electrons are presented for different field sizes and cases. Materials and Methods: The Monte Carlo code, MCNPX, has been used to simulate 18 MV photon beam from a Varian Linac-2300 accelerator. All dose measurements were carried out using a PTW-MP2 scanner with an ionization chamber (0.6 CC) at the water phantom. Results: The maximum electron contaminant dose at the surface ranged from 6.1 for 5 � 5 cm2 to 38.8 for 40 � 40 cm2 and at the depth of maximum dose was 0.9 up to 5.77 for the 5 � 5 cm2 to the 40 � 40 cm2 field sizes, respectively. The additional contaminant electron dose at the surface for the field with tray increased 2.3 for 10 � 10 cm2, 7.3 for 20 � 20 cm2, and 21.4 for 40 � 40 cm2 field size comparing to the standard field without any accessories. This increase for field with tray and shaping block was 5.3 and 13.3 for 10 � 10 and 20 � 20 cm2, respectively, while, the electron contamination decreased for the fields with wedge, i.e. 2.2 for the 10 � 10 cm2 field. Conclusion: The results have provided more comprehensive knowledge of the high-energy clinical beams and may be useful to develop the accurate treatment planning systems capable of taking the electron contamination in to account

Novel links between ciliopathies and FGF-related craniofacial syndromes

K Liu1*, JT Tabler1, HL Szabo-Rogers1, A Mesbahi1, C Healy1, W Barrell1, B Wlodarczyk2, Author Affiliations 1 King's College London, UK 2 University of Texas Southwestern, USA 3 University of Texas at Austin, USAOral Presentation : Recent studies suggest that planar cell polarity (PCP) genes coordinate cell polarity, ciliogenesis and signalling during mammalian development. FUZ is a PCP gene implicated in human congenital anomalies, including neural tube defects and orofacial clefting. Our analysis of fuzzy mutant mice reveals ciliogenesis defects in craniofacial tissues as well as a suite of phenotypes reminiscent of FGF-related craniofacial disorders. Mutants have coronal synostosis, shortened facial extensions, low-set ears and a high-arched palate. To our surprise, we found that the facial defects are due to increased neural crest migration into the first branchial arch (BA1), resulting in maxillary hyperplasia. Furthermore, the neural crest cells migrate in a disorganized fashion, deeper than normal and with fewer cell-cell contacts. This ectopic migration correlates with a dramatic increase in FGF signaling, first in the mid-hindbrain boundary, and then in the BA1 epithelia. The increased tissue causes a medial positional shift in the palatal primordia that manifests as a high-arched palate with pseudo-cleft. Genetic loss of fgf8 rescues the maxillary hyperplasia. Taken together, our data suggest a novel interplay between ciliogenesis, FGF signalling and migration of neural crest which may underlie congenital craniofacial dysmorphologies.Molecular [email protected]