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Background: Until now, the novel coronavirus 2019 (SARS-CoV-2) has caused wide dissemination in China and other 72 countries, affecting more than 90,000 peoples. Global health systems are facing the unprecedented challenges. Here we shared the experiences and lessons in emergency responses and management from our hospital, a government-assigned regional anti-COVID-19 general hospital in Nanjing, Jiangsu Province, China. Methods: All measures were designed and taken based on three periodic strategies with different emphases, in response to the epidemic progress. Beginning on January 6, 2020, an emergency leadership committee with subsidiary companion teams were established in Phase Ⅰ. Proactive preparation like infrastructure modifications and personnel training were conducted. In Phase Ⅱ, no efforts were spared on special arrangements for outpatients, surgeries, and online medical services to cut the visitors density. With continuous drop of newly confirmed cases since mid-February, regular hospital operation recovered gradually (Phase Ⅲ). COVID-19 screening flow was tailored in each phase. Questionnaires for staffs’ mental status and satisfaction were also surveyed. Findings: Since January 16, three patients were diagnosed with SARS-CoV-2 infection in our hospital. No hospital employees were infected with COVID-19. There was no case of hospital-acquired COVID-19 infection for those who received medical care in the setting of both outpatient and inpatient. During the epidemics, 6·46% staffs suffered depression, 9·87% had anxiety, and 98% were satisfied with the hospital infection control work. Shortages in staffs and medical consumables, and limitation in space were the obstacles we encountered. Interpretation: As the outbreak was rapid and sudden, and great uncertainties in COVID-19 still remain, we faced substantial challenges and difficulties. As the cost of in-hospital transmission is unbearable, our experiences and lessons suggested that prompt actions should be taken immediately to decrease or eliminate potential in-hospital transmission. Experience shared herein may be useful for those facilities who are and who may engage in COVID-19. Funding Statement: None. Declaration of Interests: The authors declare no competing interests.

Nonlinear isolators in the shape of a circular ring have been shown to have an advantage over linear isolators in that they allow low-frequency vibration isolation. These isolators have generally been assumed to possess linear viscous damping, which degrades the performance of the isolator at high frequencies. An alternative design is to make use of nonlinear damping, where the nonlinear behavior is achieved by placing linear dampers, so that they are orthogonal to the motion of the isolator. In this work, the performance of circular ring isolators with this type of damping is compared with the corresponding isolators exhibiting linear viscous damping only. It is found that the isolators with linear viscous damping perform better around the resonance frequencies, but the isolators with nonlinear damping perform better at high frequencies.

Manipulator systems are widely used in payload capture and movement in the ground/space operation due to their dexterous manipulation capability. In this study, a method for identifying the payload parameters of a flexible space manipulator using the estimated system of complex eigenvalue matrix is proposed. The original nonlinear dynamic model of the manipulator is linearized at a selected working point. Subsequently, the system state-space model and corresponding complex eigenvalue parameters are determined by the observer/Kalman filter identification algorithm using the torque input signal of the motor and the vibration output signals of the link. Therefore, the inertia parameters of the payload, that is, the mass and the moment of inertia, can be derived from the identified complex eigenvalue system and mode shapes by solving a least-squares problem. In numerical simulations, the proposed parameter identification method is implemented and compared with the classical recursive least-squares and affine projection sign algorithms. Numerical results demonstrate that the proposed method can effectively estimate the payload parameters with satisfactory accuracy.

The present study describes a method of using a nonlinear energy sink (NES) to realize vibration reduction of the flywheel system, and integrates the NES with the flywheel support structure consisting of a simply supported plate and the flywheels to achieve vibration control. In the micro-vibration environment of the laser communication satellite, the device is proposed on the vibration attenuation of the momentum wheel system. In the system, the external excitation consists of a superposition of several discrete sinusoidal harmonics generated by the radial micro-vibration of the flywheel. A finite-element model is developed and then verified by the equivalent model results. The governing equations of the plate are discretized via the Galerkin method. The complexification-averaging (CX-A) method is employed to obtain approximate solutions. The amplitude-frequency responses of the system are obtained. The vibration suppression of the system is analyzed, and the approximate solutions are verified by numerical results. To systematically analyze the dynamic behaviors of the designed nonlinear vibration absorber, different parameters are selected for NES, and saddle-node bifurcations and Hopf bifurcations are obtained by selecting some specific parameters. The RMS ratio of the transmitted force to the excitation force is used to calculate the transmissibility of the system equipped with the NES. A parametric study is conducted for further optimization. Results illustrate that NES has a good vibration reduction effect on the micro-vibration of the system.

This paper focuses on the free and forced nonlinear vibration of a viscoelastic transporting belt supported by pulleys for the first time. The transporting belt boundary conditions are usually specified as simply supported or fixed. Therefore, the static equilibrium of the belt is supposed to remain straight. However, the belt wraps around two pulleys in most practical mechanical systems. The round support of the pulleys causes nonhomogeneous terms in the boundary condition. A nonlinear dynamic model is established to describe the transverse vibration of the transporting belt. The static equilibrium configuration caused by the nonhomogeneous boundary conditions is determined by developing a numerical iteration scheme. By means of coordinate transformation, the influence of nonhomogeneous boundary conditions is eliminated. Then, the natural frequencies of transverse vibration of the belt around the equilibrium configuration are obtained by adopting the differential quadrature method. Furthermore, the inertia excitation of the belt system is taken from the periodic motion of the foundation. In dynamic mechanical systems, this kind of fluctuation induced by the engine is very common. By applying the differential quadrature method and the Runge–Kutta time discretization, the time histories of the forced vibration are numerically calculated. Resonance areas of the belt are studied by using the frequency sweep. Moreover, parametric studies are carried out to understand the influences of the system parameters. It is concluded that pulley support ends cause nonhomogeneous boundaries and the static equilibrium configuration, and consequences are exacerbated by transmission speed.

Giant magnetostrictive material (GMM) is integrated into a nonlinear energy sink (NES) to construct a NES-GMM device for vibration control and energy harvesting. The NES-GMM device is experimentally embedded in a scaled model of a whole-spacecraft system. LMS Test.Lab software and an oscilloscope are used to collect vibration and energy signals of the whole-spacecraft system with and without the NES-GMM device under sine sweeping frequency excitations. The transmissibility amplitudes, resonant frequencies, and voltage values demonstrate the effeteness of vibration control and energy harvesting of the NES-GMM device under different various conditions. The experimental system is modeled as a two-degrees-of-freedom (2DOF) linear primary system with a nonlinear NES-GMM additional subsystem. The complexification-averaging (CX-A) method verified with numerical verifications is developed to investigate analytically the vibration reduction and energy harvesting of the NES-GMM device for the whole-spacecraft system. The experimental and theoretical results show that the NES-GMM device reduces the vibration and produces the electricity and that the device hardly changes the resonance frequencies of the original whole-spacecraft system. The saddle-node (SN) bifurcation is detected in the steady-state periodic response of the system. The performance of the NES-GMM device is examined for its varying parameters.

This paper investigates a highly efficient and promising control method for forced vibration control of an axially moving beam with an attached nonlinear energy sink (NES). Because of the axial velocity, external force and external excitation frequency, the beam undergoes a high-amplitude vibration. The Galerkin method is applied to discretize the dynamic equations of the beam–NES system. The steady-state responses of the beams with an attached NES and with nothing attached are acquired by numerical simulation. Furthermore, the fast Fourier transform (FFT) is applied to get the amplitude–frequency responses. From the perspective of frequency domain analysis, it is explained that the NES has little effect on the natural frequency of the beam. Results confirm that NES has a great potential to control the excessive vibration.

In this paper, we investigate the microfluid induced vibration of a nanotube in thermal environment. Attention is focused on a special case that the law of energy equipartition is unreliable unless the quantum effect is taken into account. A nonlocal Euler–Bernoulli beam model is used to model the transverse vibration of a single-walled nanotube (SWCNT). Results reveal that the root of mean squared (RMS) amplitude of thermal vibration of the fluid-conveying SWCNT predicted from the quantum theory is lower than that predicted from the law of energy equipartition. The quantum effect on the thermal vibration of the fluid-conveying SWCNT is more significant for the cases of higher-order modes, lower flow velocity, lower temperature, and lower fluid density.

Herein, a novel pyramid lattice sandwich structure with the active variable stiffness (AVS) is proposed, which consists of a proportion integration (PI) active controller, a piezoelectric actuator, and a variable stiffness device. The principle of AVS is to process the real-time vibration feedback signal of the lattice sandwich beam by using the PI controller and the piezoelectric actuator to change structural stiffness continuously. The structure has excellent self-adjusting and active vibration reduction effect. Based on the supersonic piston theory, Hamilton's principle, and the assumed modes method, the dynamics equations of the whole structure are established. The vibration reduction and energy dissipation of lattice sandwich beams with AVS and without AVS are analyzed by using the Runge-Kutta algorithm. Moreover, the relevant parameters of PI controller, positive stiffness, negative stiffness, incoming flow velocity, damping coefficient, and installation position are compared and analyzed, respectively. The results indicate that the novel lattice sandwich structure with AVS can achieve ideal vibration reduction effect, and the efficiency can be improved by adjusting the parameters appropriately.

A closed detached response due to the resonance response interaction has a critical effect on vibration isolation and energy harvesting. In this paper, a promising novel approach by integrating a lever-type nonlinear energy sink (LNES) and a giant magnetostrictive-piezoelectric (GMP) energy harvester (LNES-GMP) for vibration isolation and energy harvesting is investigated. The method of harmonic balance is applied to trace the response and voltage of the system, and numerical results support the harmonic solutions. It can be noted that the occurrence of closed detached resonance response could dramatically increase the voltage of the system. Moreover, the structure of the LNES-GMP, such as the mass, nonlinear stiffness, and fulcrum location may influence the efficiency of vibration isolation and energy harvesting. Lastly, with an appropriate fulcrum location, the performance of the LNES-GMP, which contains less attached mass, is more improved than the traditional NES-GMP.

A mechanical-piezoelectric system is explored to reduce vibration and to harvest energy. The system consists of a piezoelectric device and a nonlinear energy sink (NES), which is a nonlinear oscillator without linear stiffness. The NES-piezoelectric system is attached to a 2-degree-of-freedom primary system subjected to a shock load. This mechanical-piezoelectric system is investigated based on the concepts of the percentages of energy transition and energy transition measure. The strong target energy transfer occurs for some certain transient excitation amplitude and NES nonlinear stiffness. The plots of wavelet transforms are used to indicate that the nonlinear beats initiate energy transitions between the NES-piezoelectric system and the primary system in the transient vibration, and a 1:1 transient resonance capture occurs between two subsystems. The investigation demonstrates that the integrated NES-piezoelectric mechanism can reduce vibration and harvest some vibration energy.

This paper explores a promising novel approach by integrating nonlinear energy sink (NES) and giant magnetostrictive material (GMM) to realize vibration control and energy harvesting. The vibration-based apparatus consisting of a NES, a Terfenol-D rod, and a linear oscillator (the primary system) is proposed. The mathematical model of the prototype under displacement driven has been established and simulated by utilizing the Runge-Kutta algorithm. The exhibited responses and the obtained electric energy are computed. Furthermore, the Fast Fourier Transform (FFT) of the resonant responses is performed. The distribution of the input energy is calculated to evaluate the designed structure. The instantaneous transaction of the energy is then examined by considering the energy transaction measure (ETM). Lastly, a parametric study is conducted for further optimization. The numerical simulations demonstrate that the nonlinear pumping phenomena occur, that is, the target energy transfer (TET) that leads to a very efficient vibration suppression. In addition, the results also illustrate that the localized vibration energy can be converted into magnetic field energy due to the Villari effect and then transformed into electric energy.

For the first time, a new representation of transmissibility based on nonlinear output frequency-response functions (NOFRFs) is proposed in the present study. Furthermore, the transmissibility is applied to evaluate the vibration isolation performance of a nonlinear energy sink (NES) in frequency domain. A two-degree-of-freedom (2-DOF) structure with the NES attached system is adopted. Numerical simulations have been performed for the 2-DOF structure. Moreover, the effects of NES parameters on the transmissibility of the nonlinear system are evaluated. By increasing the viscous damping and mass, as well as decreasing the cubic nonlinear stiffness of the NES, the analytical results show that the transmissibility of the 2-DOF structure with NES is reduced over all resonance regions. Therefore, the present paper produces a novel method for NES design in frequency domain.

Thermal shock-induced vibration suppression of an axially moving beam with a nonlinear energy sink (NES) is investigated. Owing to thermal shock on the beam, the beam is subjected to excessive vibrations. The equation for the transverse vibration of the beam with thermal shock is established using Hamilton’s principle, and the equation for the beam with NES is approximated by the Galerkin method. A numerical algorithm is used to obtain the displacement responses of the beam with and without NES attached under thermal shock. The NES efficiencies at different positions are obtained. Results show the NES can absorb a large number of vibrational energy.

Parts energy of nonlinear system such as the closed detached response (CDR), primary response (PR), closed detached voltage (CDV), and primary voltage (PV) are resultant of the resonance response interaction and represent their corresponding dynamic characteristics. In this paper, we proposed a promising novel device by integrating a lever-type nonlinear energy sink (LNES) and a levitation magnetoelectric energy harvester (LMEH), to discover the effects of CDR, PR, CDV, and PV on the vibration isolation and energy harvesting. In nonlinear energy harvesting, the weight of the system plays a vital role in improving the accuracy, and hence it cannot be neglected. The root mean square is used to evaluate vibration control and energy harvesting. We used the method of harmonic balance to trace the CDR, PR, CDV, and PV of the system, and numerical results support the harmonic solutions. Specifically, the CDV dramatically increases the voltage of the system. The performance of vibration isolation and energy harvesting has been discussed in terms of the attached mass, nonlinear stiffness, and fulcrum location. Finally, with an appropriate fulcrum location, the performance of LNES-LMEH is compared with the traditional NES-LMEH.

The composite laminated plate is widely used in supersonic aircraft. So, there are many researches about the vibration suppression of composite laminated plate. In this paper, nonlinear energy sink (NES) as an effective method to suppress vibration is studied. The coupled partial differential governing equations of the composite laminated plate with the nonlinear energy sink (NES) are established by using the Hamilton principle. The fourth-order Galerkin discrete method is used to truncate the partial differential equations, which are solved by numerical integration method. Meanwhile study about the precise effectiveness of the nonlinear energy sink (NES) by discussing the different installation location of the nonlinear energy sink (NES) at the same speed. The results indicate that the nonlinear energy sink (NES) can significantly suppress the severe vibration of the composite laminated plate with speed wind loadings in to protect the composite laminated plate from excessive vibration.

Pancreatic head cancer is a common but the most lethal cancer of the human digestive system. It is invasive, resulting in early infiltration of adjacent structures and lymph node and distant metastases. Its biological characteristics of neurotropic growth lead to early neural invasion (NI) which is an independent prognostic factor of survival for pancreatic cancer. Radical surgical resection remains the only form of curative treatment. The extent of surgical resection and whether extended resection results in better long-term survival have been controversial. Studies have reported that peripancreatic plexus invasion is a frequent cause of pancreatic cancer recurrence and death. The relationship between cancer microenvironment and nerve cells, and whether the peripancreatic nerve plexus nearby needs to be resected require further studies. The present review aims to discuss the role of peripancreatic nerve and its implications in pancreatic head cancer resection.

In this study, a novel multifunctional nonlinear composite structure consisting of functionally graded beams and piezoelectric sheets is proposed. This structure exhibits excellent supersonic aerodynamic energy harvesting performance under heating conditions. Referring to the geometric large deformation theory, the electromechanical coupling dynamics equation of the whole structure under supersonic aerodynamic force and the thermal environment is established by Hamilton’s principle. The energy harvesting effect of piezoelectric sheets is simulated by Runge–Kutta algorithm. The correlation parameters of the length-to-fine ratio, gradient index, resistance, airflow speed, and temperature were compared and analyzed. Results show that this new multifunctional nonlinear composite structure can achieve the ideal energy harvesting effect and proper adjustment of parameters can improve the energy harvesting effect under the thermal environment. This study provides new ideas for related research on nonlinear energy harvesting under heating conditions.

Given its essential nonlinearity, nonlinear energy sink (NES) has been extensively studied as a promising vibration energy harvesting device. Internal resonance, which is due to strong energy exchange between modes, also provides a valuable idea for vibration energy harvesting. Combining these two advantages, we put forward a 3:1 internal resonance system, which consists of an NES and a coupled linear oscillator, as an enhanced method for vibration energy harvesting. The multiscale method is applied to derive the relationship between amplitude and frequency response. Simulations are carried out to evaluate the performance of the proposed method. Results show that the internal resonance system can remarkably improve the vibration energy harvesting performance. The numerical solutions verify the accuracy of the analytical solutions. The results demonstrate that the internal resonance system with NES for energy harvesting has better output power and bandwidth compared with noninternal resonance system. Overall, the comprehensive design improves the performance of NES for vibration energy harvesting.

In this paper, A novel idea is put forward. The nonlinear output frequency response functions(NOFRFs) is the first used in analyzing the dynamical equation of the model of Electro-Mechanical to achieve vibration control and energy collection. The controlling system consisting of a nonlinear energy sink(NES), gaint magnetostrictive material(GMM), 2-DOF is proposed. According to the dynamics model, setting up corresponding kinetic control equations. The nonlinear output frequency response function(NOFRFs) is devoted to calculate the kinetic equations of the 2-DOF with NES and GMM. Results prove that the NOFRFs is used for well calculating and resolving the dynamical equation of the model of 2-DOF with NES and GMM. The NES can control the excessive vibration of the model of 2-DOF obviously and suppress the vibration more effective with GMM. An reasonable designed NES-GMM can efficiently assimilate and dissipate broad band-frequency energy. GMM can collect energy form NES targeting delivery and transform the mechanical energy into the voltage and power through corresponding device.

The present study aims to investigate the steady-state response regimes of a device comprising a nonlinear energy sink (NES) and a giant magnetostrictive energy harvester utilizing analytical approximation. The complexification-averaging (CX-A) technique is generalized to systems defined by differential algebraic equations (DAEs). The amplitude-frequency responses are compared with numerical simulations for validation purposes. The tensile and compressive stresses of giant magnetostrictive material (GMM) are checked to ensure that the material functions properly. The energy harvested is calculated and the comparison of transmissibility of the apparatus with and without NES–GMM is exhibited to reveal the performance of vibration mitigation. Then, the stability and bifurcations are examined. The outcome demonstrates that the steady-state periodic solutions of the system undergo saddle-node (SN) bifurcation at a certain set of parameters. In the meantime, no Hopf bifurcation is observed. The introduction of NES and GMM for vibration reduction and energy harvesting brings about geometric nonlinearity and material nonlinearity. By computing both the responses of the primary system equipped with the NES only and the NES–GMM, it is indicated that the added GMM can dramatically modify the steady-state dynamics. A further optimization with respect to the cubic stiffness, the damper of NES, and the amplitude of excitation is conducted, respectively. The boundary where the giant magnetostrictive energy harvester is out of work is pointed out as well during the process of optimizing.

Excessive vibration of the beam with varying axial speed could be suppressed by nonlinear targeted energy transfer. Parallel nonlinear energy sink (NES) devices were attached to the beam for absorbing the vibration energy. Galerkin method was applied to discretize the equation of the integrated translating beam–NES system derived from Newton’s second law. The numerical method was used to display the effect of vibration suppression. Results showed that the parallel NES could effectively suppress the vibration of the axially moving beam. By contrast with the single NES under the same condition except the attached mass, not only the one was less and the suppressed effect was better.

An accurate model about the terahertz wave propagation in fluid-filled single-walled carbon nanotube, named non-local Euler–Bernoulli bean models, was studied in the past decade. The temperature is a key factor to study the mechanical properties of the nanostructures. This paper presents the thermal effect about single-walled carbon nanotubes. The governing equation for single-walled carbon nanotubes is developed through non-local Timoshenko beam theory, and size and surface effects are considered. The fluid flows quickly, and the terahertz wave propagation will be in the scope of the frequency. Thermal effect and liquid density significantly change the propagating frequency.

This study investigates the propagation peculiarities of the flexural wave of piezoelectric functionally graded nanobeam with surface and thermal effects. The equation of the flexural wave of the piezoelectric functionally graded nanobeam was expressed using nonlocal elastic theory because of the thermal and surface effects. The phase and group velocities were derived. The dispersion relation was analyzed using different wave numbers and temperatures and scale coefficient. The dispersion degree was weakened by scale coefficient and temperature and an increase in wave numbers. Changing the scale coefficient and temperatures are two of the main approaches in investigating the propagation characteristics of piezoelectric functionally graded nanobeam with surface effects and identifying new characteristics were found.

In order to improve the strength and toughness of materials, nanoparticle is always embedded into epoxy resin and fiber composite materials. The influence of the number, distribution and mechanical property of nanoparticle arranged around the fiber on fiber reinforced composites is evaluated in this paper. A finite element analysis under a tensile load is performed by using commercial finite element software named as ABAQUS. Both the stress contour and progressive damage failure mode of the representative volume element (RVE) model of fiber reinforced composites are obtained. A series of computational experimental results indicate that both the space geometry property and mechanical property of nanoparticle have a significant effect on the stiffness and strength properties of these composite materials.

A nonlinear energy sink (NES) approach is proposed for whole-spacecraft vibration reduction. Frequency sweeping tests are conducted on a scaled whole-spacecraft structure without or with a NES attached. The experimental transmissibility results demonstrate the significant reduction of the whole-spacecraft structure vibration over a broad spectrum of excitation frequency. The NES attachment hardly changes the natural frequencies of the structure. A finite element model is developed, and the model is verified by the experimental results. A two degrees-of-freedom (DOF) equivalent model of the scaled whole-spacecraft is proposed with the two same natural frequencies as those obtained via the finite element model. The experiment, the finite element model, and the equivalent model predict the same trends that the NES vibration reduction performance becomes better for the increasing NES mass, the increasing NES viscous damping, and the decreasing nonlinear stiffness. The energy absorption measure and the energy transition measure calculated based on the equivalent model reveals that an appropriately designed NES can efficiently absorb and dissipate broadband-frequency energy via nonlinear beats, irreversible targeted energy transfer (TET), or both for different parameters.

The propagation characteristics of the longitudinal wave in a piezoelectric nanoplate were investigated in this study. The nonlocal elasticity theory was used and the surface effects were taken into account. In addition, the group velocity and phase velocity were derived and investigated, respectively. The dispersion relation was analyzed with different scale coefficients, wavenumbers, and voltages. The results showed that the dispersion degree can be strengthened by increasing the wavenumber and scale coefficient.

For different technical reasons, cutouts such as holes in thin-walled structures are inevitable and are of significant technical relevance. Unfortunately open holes usually lead to an undesired stress concentration at the hole vicinity and a reduced load carrying ability of the structure. Therefore the mechanical properties of fiber-reinforced composite laminates with open holes are studied in the paper. The influences of the size and shape of the holes are investigated. A progressive failure finite element model is developed with software ABAQUS. Different failure modes of the composite laminates with various holes are simulated under the Hashin failure criterion. The computational results show that the hole/s have a significant effects on composite laminates properties, and the conclusion can be provided as a good reference for the design of the composite laminates with hole/s.

The purpose of the present study was to evaluate the efficacy of extended pancreatoduodenectomy (EPD) and standard pancreatoduodenectomy (SPD) for ductal adenocarcinoma of the head of the pancreas via meta-analysis.Relevant articles (published between 1995 and 2012) were compiled from online data sources. A total of nine studies satisfied the selection criteria, including a total of 973 patients (478 in the SPD group and 495 in the EPD group). Evaluation parameters included 1-, 3-, and 5-year survival, as well as mortality, morbidity, and specific morbidity outcomes.Meta-analysis revealed (1) differences in morbidity (Odds ratio [OR] = 1.740; 95 % confidence interval [CI], 0.840-3.600; P = 0.140), mortality (OR = 0.890; 95 % CI, 0.560-1.400; P = 0.620), 1-year overall survival (OS) rate (OR = 1.20; 95 % CI, 0.490-2.930; P = 0.69), 3-year OS rate (OR = 0.770; 95 % CI, 0.460-1.280; P = 0.190), and 5-year OS rate (OR = 1.12; 95 % CI, 0.690-1.810; P = 0.560) were not significant between EPD and SPD. (2) For bile leak (OR = 2.640; 95 % CI, 1.040-6.700; P = 0.040), pancreatic leak (OR = 1.740; 95 % CI, 1.040-2.91; P = 0.030), delayed gastric emptying (OR = 2.090; 95 % CI, 1.240-3.520; P = 0.006), and lymphatic fistula (OR = 6.120; 95 % CI, 1.06-35.320; P = 0.040) differences between EPD and SPD were significant, whereas other specific morbidities were not significantly different.Extended pancreatoduodenectomy does not improve 1-, 3-, 5-year OS rates compared to SPD and there is a trend toward increased bile leak, pancreatic leak, delayed gastric emptying, and lymphatic fistula after EPD.

A new multifunctional lattice sandwich structure consisting of a lattice sandwich beam, a nonlinear energy sink (NES) and a giant magnetostrictive material (GMM) is proposed in this research. This structure exhibits excellent self-vibration suppression and aeroelastic energy harvesting performance. The dynamic equations of the whole structure are established using Hamilton principle and Newton’s second law, and the Runge-Kutta algorithm is used to obtain the amplitude response of the beam coupled with NES and without NES, which can indicate the vibration control effect of NES. Moreover, the energy harvest effect of the structure with GMM is also analyzed through numerical simulation. And a comparative analysis of relevant parameters such as NES mass, spring stiffness and damping coefficient is also implemented. The results show that this new multifunctional lattice sandwich structure can achieve the desired effect of vibration suppression and energy harvesting, and proper adjustment of parameters will improve the effect. This study provides a new idea for related research on vibration control and energy harvesting.

Based on the techniques of surface mechanical attrition treatment, laminated and nanostructured materials with high strength and high ductility can be produced. In order to capture the deformation behaviour and associated damage initiation/evolution process in the layered surface mechanical attrition treated 304SS (stainless steel), a cohesive model is employed into finite element method to investigate the effects of the constituent materials on the overall strength and ductility of layered surface mechanical attrition treated 304SS in the present paper. It is found that the normal cohesive strength, tangential cohesive strength and fracture energy of both the nanograin layer and the surface mechanical attrition treated 304SS layer have a significant influence on the failure strain of layered corolled surface mechanical attrition treated 304SS. Simulation results also indicate that the layered bonded surface mechanical attrition treated 304SS may be superior to the layered corolled surface mechani...

This paper studied the dynamic suppression problems of active control of composite panel with uncertain parameters. Considering uncertain factors of panel, finite element vibration dynamic model is established for active vibration control, through interval analysis method to estimate panel in active control of vibration critical air speed and flutter amplitude, to this determined active suppression effects of panel, numerical simulation indicate that through with Piezoelectric patches as active vibration control, the panel with uncertain parameters of whole interval of vibration critical wind speed were changed from vibration to convergence, showing that the control effect was significant.

In this paper, the vibration suppression mechanism of a nonlinear fluid pipe via nonlinear energy sink (NES) is studied for the first time. The fluid pipe is simply supported under harmonic foundation excitation. The complexification-averaging method combined with the arc-length continuation method is used to predict the response of the system. The analytical solution is supported by the numerical result. The trend of interaction between liquid speed and NES parameters are investigated by comparison of parameters optimization. It is especially pointed out that the change of stiffness has a very complicated influence on the response. The parameters optimization is investigated at the resonance frequency. It is noted that the liquid speed has an important effect on the vibration suppression of the fluid pipe. Besides, the system is evaluated from the point of view of energy. The distribution of the input energy is calculated and the instantaneous transaction of the energy is examined by considering the energy transaction measure (ETM). The numerical simulations demonstrate that the target energy transfer (TET) leads to a very efficient vibration suppression.

A whole-spacecraft vibration isolation platform can improve the dynamic environment during satellite launches. In this paper, the dynamic characteristics of a whole-spacecraft vibration isolation platform with uncertain parameters are investigated. The governing equation of the platform is derived and the non-probabilistic reliability theory is utilized to analyze the dynamic characteristics. Then, the numerical results are carried out and compared with the experimental data. It is found that non-probabilistic reliability theory is a powerful tool to reveal the dynamic characteristics, which may lead to a new design of the platform with enhanced security and reliability.

Background & Aims We aimed at investigating the effects of the targeted transduction of the Wtp53-pPRIME-miR30-shRNA gene into liver cancer cells, under the mediation of anti-alpha fetoprotein scFv-directed lentivirus, and the inhibitory effect of this system on liver cancer cells. Methods The result of infection was observed by fluorescence microscopy. Polymerase chain reaction and Western blotting were used to demonstrate the successful transduction and transcription of the Wtp53-pPRIME-miR30-shRNA-IGF1R gene. Cell growth was observed via the Cell-Counting Kit-8 Method, and cell apoptosis was detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling. To observe further the effects of AFP-Wtp53-pPRIME-miR30-shRNA-IGF1R therapy in animals, models of BALB-C nude mice bearing subcutaneous human hepatocellular carcinoma were established. The influence of the growth of subcutaneously transplanted tumor, expression of Wtp53 protein, apoptosis, and microvessel formation on the overall level of AFP-Wtp53 pPRIME-miR30-shRNA-IGF1R were also evaluated. Results Recombinant lentivirus was successfully constructed, and its functional plaque-forming unit titer was determined as 4.58×10 9 plaque-forming units/ml. A positive strand was detected by polymerase chain reaction and Western blotting. Lentiviral construction worked effectively in AFP-positive liver cancer cells. In vitro and in vivo experiments showed that the recombinant lentivirus was more efficacious in inhibiting the proliferation of Hep3B cells. Conclusions The Wtp53-pPRIME-miR30-shRNA gene can be subjected to targeted transduction into liver cancer cells under the mediation of anti-alpha fetoprotein scFv-directed lentivirus. The Wtp53-pPRIME-miR30-shRNA system has targeting ability and lethal effects on liver cancer cells.

PurposeThe purpose of this paper is to analyze a new, whole‐spacecraft isolator and its performance of vibration isolation, which has been designed to ensure spacecraft safety at the launching stage.Design/methodology/approachThe design is based on the analysis of fractional derivative stress‐strain constitutive relationship of viscoelastic materials. First, the authors study the constitutive relationships for viscoelastic solid of the damping materials, then the authors introduce the results obtained to the equations of motion for the damped isolator.FindingsBy performing a series of transformation, the authors obtain the analytical solution of the equations. It is shown that the results compare favourably to the numerical simulations and experiments. In addition, a saturation phenomenon for the first order damping ratio is also discussed.Practical implicationsIt is found that the constitutive relationships written in terms of the fractional calculus can be applied in the system function of the whole‐spacecraft vibration isolator. Such relationships, developed previously from a model analysis base, have been shown to be useful tools for engineering analyses.Originality/valueSome suggestions are given to improve the design of viscoelastic whole‐spacecraft isolators. The establishment of a theoretical basis for the new fractional differential dynamical system enhances their value, as they may now be used with increased reliability of satellite.

The method for evaluating the vibration isolation performance of discrete whole-spacecraft vibration isolation of flexible spacecrafts is studied in the paper. The dynamic model of the discrete whole-spacecraft system is built and model reduction is proposed. The analysis of vibration isolation method of vibration transmissibility from the isolator to satellite is discussed. Then, the evaluation method is studied from the perspective of simulation and experiment, and the results show the correctness of the theoretical analysis. The power flow evaluation method of discrete whole-spacecraft of the flexible spacecraft is introduced. By studying the power flow of the vibration isolation, we find that this method supplements inadequacies of the vibration transmissibility. At last, it is proposed that the vibration isolation performance should be evaluated by combining the vibration transmissibility at some key points of the satellite and the power flow of the vibration isolator.

To explore the use of superior mesenteric vein-caval-right atrium Y shunt (SMV-CV-RA Y shunt) as a treatment for Budd-Chiari syndrome (B-CS) with a long stenotic segment of IVC ≥ 2 cm and complete obstruction of all major hepatic veins with no compensating hypertrophy of the small hepatic veins that drain from the liver into the inferior vena cava (IVC) (type IIIB mixed pattern of B-CS).The clinical data of 101 consecutive patients with this mixed pattern of B-CS treated by surgery using artificial vascular grafts were retrospectively studied: 62 patients were treated with SMV-CV-RA Y shunt compared with historical groups of 26 patients treated with splenic vein-caval shunt and 13 patients with superior mesenteric vein-caval shunt.On follow-up, the clinical results assessed to be good/improved for the groups of patients who received SMV-CV-RA Y shunt, splenic vein-caval shunt, and superior mesenteric vein-caval shunt were 57/62 (91.9%), 11/26 (42.3%), and 5/13 (38.5%), respectively (P0.05). The patency rates of the artificial vascular grafts were 95.2% (59/62), 69.2% (18/26), and 38.4% (5/13), respectively (P0.05). Compared with patients who received splenic vein-caval shunt and superior mesenteric vein-caval shunt, the platelet count of the 62 patients who received SMV-CV-RA Y shunt increased significantly 1 mo after surgery (P0.05). The portal venous pressure of the patients with SMV-CV-RA Y shunt decreased significantly than before shunting (P0.05), although this pressure decrease in patients who received splenic vein-caval shunt and superior mesenteric vein-caval shunt were insignificant (P0.05).Compared with the historical splenic vein-caval shunt and superior mesenteric vein-caval shunt, SMV-CV-RA Y shunt more satisfactorily improved clinical results of patients with a special mixed pattern of B-CS, and in reducing the portal and inferior vena venous pressures. The shunt could reverse hypersplenism. The splenic vein-caval shunt and superior mesenteric vein-caval shunt were not useful for this type of patients.

The influence of the distribution type, Young's modulus, and volume fraction of the nanoparticles within the interphase region on the mechanical behavior of long fiber-reinforced composites with epoxy resin matrix under transverse tensile loading is investigated in this article. An infinite material containing unidirectional long fiber and periodic distribution of elastic, spherical nanoparticles was modeled using a unit cell approach. A stiffness degradation technique has been used to simulate the damage and crack progress of the matrix subjected to mechanical loading. A series of computational experiments performed to study the influence of the nanoparticle indicate that the mechanical properties, nanoparticle-fiber distance, and volume fraction of nanoparticle have a significant effect on both the stiffness and strength properties of these composite materials. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41573.

In the present paper, free vibration of a rotating ring supported by an elastic foundation is studied by analytical method, finite element (FE) simulation and experiment. By adopting the ring analogy of Timoshenko beam theory, the nonlinear vibration of the rotating ring on an elastic foundation is modeled based on Hamilton’s principle. Radial and tangential deformation are considered. By solving the generalized eigenvalue problem, natural frequencies and flexural modes are obtained. Furthermore, the Euler–Bernoulli (E–B) theory is also employed to investigate the free vibration. For determining the necessity of the Timoshenko theory, the flexural vibration frequencies from two theories are compared. Specifically, the effects of the radius and the radial height (the thickness) of the ring on the difference between the two models are studied. In order to confirm the analytical results, finite element analysis and experiments on three test specimens are used to verify the natural frequency and flexural mode predictions. Overall, this work shows the necessity of the Timoshenko theory for studying free vibration of an elastic ring.

Background and purpose Hypofractionated radiotherapy has been the principal curative treatment option for early stage NSCLC patients who are medically inoperable or those who refuse surgery and achieved favorable clinical outcomes. Evidence demonstrated that the linear quadratic model widely used in normally fractionated radiotherapy cannot work well to fit outcome data by use of BED to predict the effect of hypofractionation schemes. New models and the related metrics need to be developed to quantify the effect of high-dose ablative regimens for early stage NSCLC. Patients and methods Trials using hypofractionated radiotherapy without chemotherapy to treat early stage ( T 1 or T 2 N 0 M 0 ) primary NSCLC and providing information on patient numbers, age, T stage and local control rates were eligible. The endpoint was local relapse and the covariates analyzed were total radiotherapy dose, dose per fraction or combinations of the two parameters, treatment duration, T stage and median age of patients within the trial. The model used was a multivariate logistic regression. Results 19 trials were included (767 patients) in which 90 patients suffered local relapse. Only total dose×dose per fraction ( D × d ) and stage T had statistically significant effect on local control. Smaller T stage ( p =0.000) and increasing D × d ( p =0.006) were associated with improved probability of local control. In contrast, BED 10 had no significant impact on local control, which probably indicated that D × d might be a more effective metric than BED 10 to predict tumor control rate and assess the efficacy of the large dose fractionation schemes for early stage NSCLC. Conclusions BED was not an ideal metric to estimate the effect of the schemes of high-dose ablative radiotherapy for early stage NSCLC, and total dose×fraction dose could be considered as a comparable index, though the result need to be further validated.

Nonlinear targeted energy transfer (TET) is applied to suppress the excessive vibration of an axially moving string with transverse wind loads. The coupling dynamic equations used are modeled by a nonlinear energy sink (NES) attached to the string to absorb vibrational energy. By a two-term Galerkin procedure, the equations are discretized, and the effects of vibration suppression by numerical methods are demonstrated. Results show that the NES can effectively suppress the vibration of the axially moving string with transverse wind loadings, thereby protecting the string from excessive movement.

The vibration active control of the composite panels with the uncertain parameters in the hypersonic flow is studied using the non-probabilistic reliability theory. Using the piezoelectric patches as active control actuators, dynamic equations of panel are established by finite element method and Hamilton’s principle. And the control model of panel with uncertain parameters is obtained. According to the non-probabilistic reliability index, and besides being based on H∞ robust control theory and non-probabilistic reliability theory, the non-probabilistic reliability performance function is given. Moreover, the relationships between the robust controller and H∞ performance index and reliability are established. Numerical results show that the control method under the influence of reliability, H∞ performance index, and approaching velocity is effective to the vibration suppression of panel in the whole interval of uncertain parameters.

To study the clinicopathological and immunohistochemical features, histogenesis and biological behavior, clinical treatment and prognosis of solid pseudopapillary tumor of the pancreas (SPT).Routine HE and immunohistochemical (SP) stainings were used in the pathological examination of 18 cases of SPT. Their clinical data were retrospectively analyzed. All the 18 postoperative patients were followed-up for 3 months to 10 years with an average of 29.2 months.There were 16 females and 2 males, age ranging from 9 to 65 years with mean age of 25.3 years. Abdominal pain and palpable mass were among the major complains. Tumors were encapsulated and mixed with solid and cystic tissues. Histological features were pseudopapillary structure with a fibrovascular core. Immunhistologically, most tumors were positive for alpha-AT, alpha-ACT and Vim, with a high percentage of 94.4%. The eighteen cases were followed-up from 3 to 120 months. Five cases received reoperation after recurrence, and 14 cases were alive. Maximum survival time was 121 months and the minimum survival time was 3 months, with a median survival time of 23.0 months. The 5-year survival rate was 72.2%. A Kaplan-Meier analysis revealed that patient's age, tumor size, pathologic features, metastasis were major prognostic factors for SPT.SPT is a tumor of low-grade malignancy and may be derived from multipotent stem cells. SPT most frequently affects young female, and has distinct clinicopathologic manifestation with excellent prognosis after surgical treatment.