Z' Mediated Flavor Changing Neutral Currents in B Meson Decays

We study the effects of an extra U(1)' gauge boson with flavor changing couplings with fermion mass eigenstates on certain B meson decays that are sensitive to such new physics contributions. In particular, we examine to what extent the current data on B_d -> \phi K, B_d -> \eta' K and B_s -> \mu^+ \mu^- decays may be explained in such models, concentrating on the example in which the flavor changing couplings are left-chiral. We find that within reasonable ranges of parameters, the Z' contribution can readily account for the anomaly in S_{\phi K_S} but is not sufficient to explain large branching ratio of B_d -> \eta' K with the same parameter value. S_{\phi K_S} and S_{\eta' K_S} are seen to be the dominant observables that constrain the extra weak phase in the model.Comment: 12 pages, 6 figures. Additional references added. Small modifications and corrections to Eq.(33) and (34) adde

Tetrahydrofuran Cembranoids from the Cultured Soft Coral Lobophytum crassum

Three new cembranoids, culobophylins A–C (1–3), along with two known compounds (4 and 5) were isolated from the cultured soft coral Lobophytum crassum. The structures of these compounds were elucidated on the basis of their spectroscopic data and comparison of the NMR data with those of known analogues. Among these metabolites, 2 is rarely found in cembranoids possessing an isopropyl moiety with an epoxide group. Compound 1 exhibited significant cytotoxic activity against HL60 and DLD-1 cancer cell lines

A Case of Ciliary Body Melanocytoma Presenting as a Painful Iris Mass

We report a case of ciliary body melanocytoma in a Korean patient, which presented as an intermittently painful pigmented iris mass and was successfully managed by iridocyclectomy. A 52-year-old healthy man presented with an irregularly-shaped and heavily-pigmented mass at the iris root of his right eye. Visual acuity of the right eye was 20/20 with normal intraocular pressure. Ultrasound biomicroscopy showed a 1.5x1.3-mm ciliary-body mass with extension into the iris root. Iridocyclectomy with scleral resection under a lamellar scleral flap was performed, and the histopathologic features of the resected tissue were consistent with melanocytoma of the ciliary body. The patient's visual acuity remained 20/20 with good postoperative cosmesis. During one year of follow-up, no signs of tumor recurrence were seen, and the patient reported resolution of the intermittent ocular pain in the involved eye

Ion Write Microthermotics: Programing Thermal Metamaterials at the Microscale.

Considerable advances in manipulating heat flow in solids have been made through the innovation of artificial thermal structures such as thermal diodes, camouflages, and cloaks. Such thermal devices can be readily constructed only at the macroscale by mechanically assembling different materials with distinct values of thermal conductivity. Here, we extend these concepts to the microscale by demonstrating a monolithic material structure on which nearly arbitrary microscale thermal metamaterial patterns can be written and programmed. It is based on a single, suspended silicon membrane whose thermal conductivity is locally, continuously, and reversibly engineered over a wide range (between 2 and 65 W/m·K) and with fine spatial resolution (10-100 nm) by focused ion irradiation. Our thermal cloak demonstration shows how ion-write microthermotics can be used as a lithography-free platform to create thermal metamaterials that control heat flow at the microscale

A Programmably Compliant Origami Mechanism for Dynamically Dexterous Robots

We present an approach to overcoming challenges in dynamical dexterity for robots through programmably compliant origami mechanisms. Our work leverages a one-parameter family of flat sheet crease patterns that folds into origami bellows, whose axial compliance can be tuned to select desired stiffness. Concentrically arranged cylinder pairs reliably manifest additive stiffness, extending the programmable range by nearly an order of magnitude and achieving bulk axial stiffness spanning 200–1500 N/m using 8 mil thick polyester-coated paper. Accordingly, we design origami energy-storing springs with a stiffness of 1035 N/m each and incorporate them into a three degree-of-freedom (DOF) tendon-driven spatial pointing mechanism that exhibits trajectory tracking accuracy less than 15% rms error within a (2 cm)^3 volume. The origami springs can sustain high power throughput, enabling the robot to achieve asymptotically stable juggling for both highly elastic (1 kg resilient shotput ball) and highly damped (“medicine ball”) collisions in the vertical direction with apex heights approaching 10 cm. The results demonstrate that “soft” robotic mechanisms are able to perform a controlled, dynamically actuated task