Phylogenomics and integrative taxonomy reveal two new species of Amana(Liliaceae)

Until now the genus Amana(Liliaceae),known as ’East Asian tulips’,has contained just seven species.In this study,a phylogenomic and integrative taxonomic approach was used to reveal two new species,Amana nanyueensis from Central China and A.tianmuensis from East China.A.nanyueensis resembles Amana edulis in possessing a densely villous-woolly bulb tunic and two opposite bracts,but differs in its leaves and anthers.Amana tianmuensis resembles Amana erythronioides in possessing three verticillate bracts and yellow anthers,but differs in aspects of its leaves and bulbs.These four species are clearly separated from each other in principal components analysis based on morphology.Phylogenomic analyses based on plastid CDS further support the species delimitation of A.nanyueensis and A.tianmuensis and suggests they are closely related to A.edulis.Cytological analysis shows that A.nanyueensis and A tianmuensis are both diploid(2n=2x=24),different from A edulis,which is either diploid(northern populations) or tetraploid(southern populations,2n=4x=48).The pollen morphology of A.nanyueensis is similar to other Amana species(single-groove germination aperture),but A.tianmuensis is quite different because of the presence of a sulcus membrane,which creates the illusion of double grooves.Ecological niche modelling also revealed a niche differentiation between A.edulis,A.nanyueensis and A.tianmuensis.

Computational Research on Modular Undulating Fin for Biorobotic Underwater Propulsor

Biomimetic design employs the principles of nature to solve engineering problems. Such designs which are hoped to be quick, efficient, robust, and versatile, have taken advantage of optimization via natural selection. In the present research, an environment-friendly propulsion system mimicking undulating fins of stingray was built. A non-conventional method was considered to model the flexibility of the fins of stingray. A two-degree-of-freedom mechanism comprised of several linkages was designed and constructed to mimic the actual flexible fin, The driving linkages were used to form a mechanical fin consisting of several fin segments, which are able tO produce undulations, similar to those produced by the actual fins. Owing to the modularity of the design of the mechanical fin, various undulating patterns can be realized. Some qualitative observations, obtained by experiments, predicted that the thrusts produced by the mechanical fin are different among various undulating patterns. To fully understand this experimental phenomenon is very important for better performance and energy saving for our biorobotic underwater propulsion system. Here, four basic undulating patterns of the mechanical fin were performed using two-dimensional unsteady computational fluid dynamics （CFD） method. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive re-meshing was used to compute the unsteady flow around the fin through twenty complete cycles. The pressure distribution on fin surface was computed and integrated to provide fin forces which were decomposed into rift and thrust. The pressure force and friction force were also computed throughout the swimming cycle. Finally, vortex contour maps of these four basic fin undulating patterns were displayed and compared.

Numerical and Experimental Research on Modular Oscillating Fin

Fishes are famous for their ability to position themselves accurately even in turbulent flows. This ability is the result of the coordinated movement of fins which extend from the body. We have embarked on a research program designed to develop an agile and high efficient biologically inspired robotic fish based on the performance of hybrid mechanical fms. To accomplish this goal, a mechanical ray-like fin actuated by Shape Memory Alloy （SMA） is developed, which can realize both oscillatory locomotion and undulatory locomotion. We first give a brief introduction on the mechanical structure of our fin and then carry out theoretic analysis on force generation. Detailed information of these theoretical results is later revealed by Computational Huid Dynamic （CFD）, and is final validated by experiments. This robotic fin has potential application as a propulsor for future underwater vehicles in addition to being a valuable scientific instrument.

A Computational Fluid Dynamics (CFD) Analysis of an Undulatory Mechanical Fin Driven by Shape Memory Alloy

Many fishes use undulatory fin to propel themselves in the underwater environment. These locomotor mechanisms have a popular interest to many researchers. In the present study, we perform a three-dimensional unsteady computation of an undulatory mechanical fin that is driven by Shape Memory Alloy （SMA）. The objective of the computation is to investigate the fluid dynamics of force production associated with the undulatory mechanical fin. An unstructured, grid-based, unsteady Navier-Stokes solver with automatic adaptive remeshing is used to compute the unsteady flow around the fin through five complete cycles. The pressure distribution on fin surface is computed and integrated to provide fin forces which are decomposed into lift and thrust. The velocity field is also computed throughout the swimming cycle. Finally, a comparison is conducted to reveal the dynamics of force generation according to the kinematic parameters of the undulatory fin （amplitude, frequency and wavelength）.

Efficacy and Safety of the WATCHMAN Left Atrial Appendage System for Stroke Prevention in Chinese Patients with Nonvalvular Atrial Fibrillation： A Single-center, Prospective, Observational Study

Background： In patients with nonvalvular atrial fibrillation （NVAF）, embolic stroke is thought to be associated with left atrial appendage （LAA） thrombi. The WATCHMAN LAA Occlusion Device has been shown to be noninferior to conventional oral anticoagulation with warfarin for stroke prevention in patients with NVAF. This study aimed to evaluate the procedural feasibility, safety and 12-month outcomes of the WATCHMAN LAA Occlusion Device in NVAF patients with high risk for stroke in China. Methods： The clinical data of 106 NVAF patients, who were consecutively underwent LAA closure with the WATCHMAN Device between April 2014 and May 2015, were collected. Patients were followed up at 1,3, 6, and 12 months after discharge. A transesophageal echocardiograph was performed at 45 days after implantation and repeated in case of an unexpected event during the follow-up period. Results： This study included 106 NVAF patients with a mean age of 64.2 ± 8.6 years （ranging from 50 to 88 years）, and the mean CHA,DS,-VASc score of all patients was 3.6 ± 1.6 （ranging from 2 to 9）. Among those 106 NVAF patients, 100 （94.3%） patients were implanted with the device successfully. The procedural success rate was 94.3% （100/106）, and the occlusion rate was 100.0% （100/100）. There were one tamponade, one ischemic stroke, and eight minor pericardial effusions during hospitalization. During 12-month follow-up period, two patients developed a tbrombus layer on the device that resolved with additional anticoagulation： one with visible device-thrombus experienced transient ischemic stroke, and one had a hemorrhagic stroke. There were no deaths in this study. The overall survival rate was 100.0%, and nonmajor adverse event rate was 95.0% （95/100）. In this study, the expected annual rate ofischemic stroke risk in these patients according to the CHA2DS2-VASc score was 4.0%, while the observed ischemic stroke rate was 2.0% per year. Conclusions： LAA closure with the WATCHMAN Device was feasible, efficient, and safe for NVAF to prevent the accidence of stroke in Chinese patients. During the 12-month follow-up period, the observed ischemic stroke rate （2.0% per year） in our study was lower than the predicted annual stroke risk （4.0%） using the CHA2DS：-VASc score.

Fabrication and Performance of a Low Operating Pressure Nanofiltration Poly(vinyl chloride) Hollow Fiber Membrane

A low operating pressure nanofiltration membrane is prepared by interfacial polymerization between m-phenylenediamine （MPDA） and trimesoyl chloride （TMC） using PVC hollow fiber membrane as supporting. A series of PVC nanofiltration membranes with different molecular weight cutoff （MWCO） can be obtained by controlling preparation conditions. Chemical and morphological characterization of the membrane surface was carried out by FTIR-ATR and SEM. MWCO was characterized by filtration experiments. The preparation conditions were investigated in detail. At the optimized conditions （40 min air-dried time, aqueous phase containing 0.5% MPDA, 0.05% SDS and 0.6% acid absorbent, oil phase containing 0.3% TMC, and 1 min reaction time）, under 0.3 MPa, water flux of the gained nanofiltration membrane reaches 17.8 L/m2-h, and the rejection rates of methyl orange and MgSO4 are more than 90% and 60%, respectively.

Fabrication of Hydrophilic and Sponge-like PVDF/Brush-like Copolymer Blend Membranes Using Triethylphosphate as Solvent

Porous PVDF blend membranes with good hydrophilicity and a symmetric structure were prepared by the phase inversion method using amphiphilic brush-like copolymers, P（MMA-r-PEGMA）, as hydrophilic additive and triethylphosphate （TEP） as solvent. P（MMA-r-PEGMA） was synthesized by radical polymerization in TEP. Then the obtained amphiphilic copolymer solution was mixed with PVDF and TEP to prepare the dope solution. The effects of P（MMA-r-PEGMA） content and coagulation composition on membrane morphologies were investigated using scanning electron microscopy （SEM）. The results demonstrated that, even blended with amphiphilic copolymers, a symmetric structure can be formed. Hollow fiber membranes with a mainly symmetric structure were also fabricated. The dry hollow fiber membranes showed good hydrophilicity, high flux and good rejection performance because of their hydrophilic surface and pores wall.

Design and motion testing of a Multiple SMA fin driven BIUV

Fishes interact with the fluid environment using various surfaces.These multiple control surfaces work in combination to produce the thrust and the balance torques in a steady swimming,to maneuver and to position themselves accurately even in turbulent flows.These motivate us to embark on a research program designed to develop an agile biologically inspired robotic fish based on the performance of multiple fins.To accomplish this goal,a mechanical ray-like fin actuated by the shape memory alloy (SMA) is developed,which can realize the oscillating motion,the undulating motion or even the complex three dimensional motion.The basic unit is the two opposite side SMA-driven plate,namely the fin ray.As a result,a lightweight bio-inspired fin is constructed by placing radially multiple SMA fin rays.A biologically inspired underwater vehicle (BIUV) is later built using the above multiple lightweight bio-inspired fins.Two common arrangement styles of multiple fins on the BIUV are considered here:one is the posterior fin (for the oscillating motion) that is parallel to the anterior fins (for the undulating motion),another one is the posterior fin that perpendicular to the anterior fins.The kinematic modeling,the deformation modeling and the detecting of the SMA fin are made.The thrust generation is also established.Finally,an experiment is conducted to test the performance of the proposed two arrangement styles,including the comparison of the averaged propulsion velocity and the averaged thrust under certain kinematic parameters.Meanwhile,the influence of the frequency and the amplitude of the SMA fin ray on the propulsion performance is also investigated.