Generalized nonreciprocity in an optomechanical circuit via synthetic magnetism and reservoir engineering

Synthetic magnetism has been used to control charge neutral excitations for applications ranging from classical beam steering to quantum simulation. In optomechanics, radiation-pressure-induced parametric coupling between optical (photon) and mechanical (phonon) excitations may be used to break time-reversal symmetry, providing the prerequisite for synthetic magnetism. Here we design and fabricate a silicon optomechanical circuit with both optical and mechanical connectivity between two optomechanical cavities. Driving the two cavities with phase-correlated laser light results in a synthetic magnetic flux, which in combination with dissipative coupling to the mechanical bath, leads to nonreciprocal transport of photons with 35dB of isolation. Additionally, optical pumping with blue-detuned light manifests as a particle non-conserving interaction between photons and phonons, resulting in directional optical amplification of 12dB in the isolator through direction. These results indicate the feasibility of utilizing optomechanical circuits to create a more general class of nonreciprocal optical devices, and further, to enable novel topological phases for both light and sound on a microchip.Comment: 18 pages, 8 figures, 4 appendice

Dynamic manipulation of mechanical resonators in the high amplitude regime through optical backaction

Cavity optomechanics enables active manipulation of mechanical resonators through backaction cooling and amplification. This ability to control mechanical motion with retarded optical forces has recently spurred a race towards realizing a mechanical resonator in its quantum ground state. Here, instead of quenching optomechanical motion, we demonstrate high amplitude operation of nanomechanical resonators by utilizing a highly efficient phonon generation process. In this regime, the nanomechanical resonators gain sufficient energy from the optical field to overcome the large energy barrier of a double well potential, leading to nanomechanical slow-down and zero frequency singularity, as predicted by early theories . Besides fundamental studies and interests in parametric amplification of small forces, optomechanical backaction is also projected to open new windows for studying discrete mechanical states, and to foster applications. Here we realize a non-volatile mechanical memory element, in which bits are written and reset via optomechanical backaction by controlling the mechanical damping across the barrier. Our study casts a new perspective on the energy dynamics in coupled mechanical resonator - cavity systems and enables novel functional devices that utilize the principles of cavity optomechanics.Comment: 22 pages, 5 figure

Nano-Opto-Electro-Mechanical Systems

A new class of hybrid systems that couple optical, electrical and mechanical degrees of freedom in nanoscale devices is under development in laboratories worldwide. These nano-opto-electro-mechanical systems (NOEMS) offer unprecedented opportunities to dynamically control the flow of light in nanophotonic structures, at high speed and low power consumption. Drawing on conceptual and technological advances from cavity optomechanics, they also bear the potential for highly efficient, low-noise transducers between microwave and optical signals, both in the classical and quantum domains. This Progress Article discusses the fundamental physical limits of NOEMS, reviews the recent progress in their implementation, and suggests potential avenues for further developments in this field.Comment: 27 pages, 3 figures, 2 boxe

ICAR: endoscopic skull‐base surgery

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WSES Jerusalem guidelines for diagnosis and treatment of acute appendicitis

Acute appendicitis (AA) is among the most common cause of acute abdominal pain. Diagnosis of AA is challenging; a variable combination of clinical signs and symptoms has been used together with laboratory findings in several scoring systems proposed for suggesting the probability of AA and the possible subsequent management pathway. The role of imaging in the diagnosis of AA is still debated, with variable use of US, CT and MRI in different settings worldwide. Up to date, comprehensive clinical guidelines for diagnosis and management of AA have never been issued. In July 2015, during the 3rd World Congress of the WSES, held in Jerusalem (Israel), a panel of experts including an Organizational Committee and Scientific Committee and Scientific Secretariat, participated to a Consensus Conference where eight panelists presented a number of statements developed for each of the eight main questions about diagnosis and management of AA. The statements were then voted, eventually modified and finally approved by the participants to The Consensus Conference and lately by the board of co-authors. The current paper is reporting the definitive Guidelines Statements on each of the following topics: 1) Diagnostic efficiency of clinical scoring systems, 2) Role of Imaging, 3) Non-operative treatment for uncomplicated appendicitis, 4) Timing of appendectomy and in-hospital delay, 5) Surgical treatment 6) Scoring systems for intra-operative grading of appendicitis and their clinical usefulness 7) Non-surgical treatment for complicated appendicitis: abscess or phlegmon 8) Pre-operative and post-operative antibiotics.Peer reviewe

Cytotoxic effects of Clusterin antisense oligonucleotides and Docetaxel on two prostate cancer cell lines

Background: Clusterin is a glycoprotein that is overexpressed under stress conditions and causes cell survival by inhibiting apoptosis. Clusterin is overexpressed in prostate cancer. Antisense RNA drugs bind to mRNA of target gene and lead to inhibition of protein translation. Objective: The aim of this study was to determine the synergistic effects of the Clusterin antisense oligonucleotides and Docetaxel on two prostate cancer cell lines. Methods: This study was conducted in the Research Institute for Biotechnology affiliated to the Iranian Research Organization for science and technology, 2013. Antisense oligonucleotides in phosphorothioate form targeting Clusterin were delivered into androgen-independent PC3 and androgen-dependent LNCaP cell lines with 25, 50, 100, 200 and 500 nanomolar concentrations. Then cell lines were treated with 100 nanomolar Docetaxel. The effect of antisense oligonucleotides with and without Docetaxel was evaluated using the MTT assay. Findings: Antisense oligonucleotides induced cell death in both PC3 and LNCaP cell lines. There was a synergistic effect between antisense oligonucleotides and Docetaxel. Conclusion: Despite the difference in cytotoxicity, there was a synergistic effect between Clusterin antisense oligonucleotides and Docetaxel in both PC3 and LNCaP cell lines. Keywords: Clusterin, Antisense RNA, Prostatic Neoplasms, Cell Lin

Evaluation of Mandibular Incisor Extraction Treatment Outcome in Patients with Bolton Discrepancy Using Peer Assessment Rating Index

Objective: Mandibular incisor extraction in carefully selected cases as an alternative option to four bicuspid extraction or non extraction treatment has been advocated.The purpose of this study was to determine the degree of improvement in occlusion in patients with Bolton discrepancy treated by one lower incisor extraction using Peer Assessment Rating Index (PAR indexes).Materials and Methods: Pre and post treatment dental casts of 14 patients treated with one lower incisor extraction were included in the study. Pre and post treatment dental casts were scored with PAR index. 70% reduction in PAR index was considered as high standard improvement. To test the hypothesis that the mean improvement in dental occlusion after one mandibular incisor extraction isat least 70%, one-tail one-sample student t-test was used.Results: The mean improvement in dental occlusion in this group of patients was 78%. Fifty percent of the cases finished with a post treatment PAR score of 2.Spearman correlation coefficient was 0.763 (p<0.01), showing that more severe cases had greater post treatment PAR scores.Conclusion: Mandibular incisor extraction treatment may provide a high standard treatment outcome