bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing the Influence of Attending Surgeon Continuity on Free Flap Outcomes Following Unplanned Returns to the Operating Room
Authors: Zhao Ruya , Shammas Ronnie L. , Broadwater Gloria , Le Elliot , Hansen-Estruch Christophe , Kaakati Rayan , Cason Roger W. , Lyes Matthew , Orr Jonah P. , Hollenbeck Scott T.
Published: June 2020

Background Unplanned returns to the operating room (OR) may be necessary at times to salvage a compromised free flap. The aim of this study was to assess the influence of attending surgeon continuity on free flap outcomes following a return to the OR.

Methods We retrospectively reviewed patients who underwent free flap reconstruction and experienced an unplanned return to the OR within 30 days from 2002 to 2017. Logistic regression modeling was used to determine factors that predict unplanned returns to the OR.

Results Of the 1,177 patients were identified, 267 (22.5%) had an unplanned return to the OR. Of these, 69 (5.9%) patients experienced total flap loss. Overall, 216 take-back procedures were performed by the primary surgeons (80.2%), while 50 were performed by covering surgeons (18.8%). Flap loss occurred more frequently during a weekend procedure (p = 0.013). Additionally, when the take-back procedure was performed within 5 days of the original surgery by the primary as opposed to a covering surgeon, patients experienced lower estimated blood loss (75 vs. 150 cc, p = 0.04). Overall, there was a significantly lower incidence of flap loss when the take-back procedure was performed by the primary, as opposed to the covering, surgeon (20 vs. 47%, p = 0.0001).

Conclusion Higher rates of flap loss occur when a covering surgeon performs a take-back procedure in comparison to the primary surgeon. It is important to ensure the availability of the primary surgeon in the first few postoperative days following free flap reconstruction. When transfer of care is necessary, photographic or video documentation of the microvascular anastomosis may be helpful in addition to a verbal sign out.
The Evolution of NIMHANS Neurotrauma Care
Authors: Bhat Dhananjaya I. , Devi B. Indira , Shukla Dhaval , Kulkarni Akshay V.
Published: June 2020

Neurotrauma services in NIMHANS, Bangalore, have been evolving since its inception in 1958. At present, it is a major referral center for Karnataka and surrounding districts of the southern states. It has many firsts to its credit, from having a separate building to having dedicated trauma teams to manage the service 24/7. It has made rapid strides in healthcare delivery based on data-driven evidence, improvisation with Lean sigma approach, and contribution through research and publications. This center has won best Neurotrauma center award in 2010.
An accurate inner diameter measurement
Authors: Mahammad Sanjid Arif , Chaudhary K. P. , Yadav Sanjay , Sen Mrinal , Ghoshal Sanjoy K
Published: June 2020

The inaccurate deflection behavior of the probing system degrades the performance of the diameter-measuring machines. In this experiment, the probing is improved, applying an autocollimator and an angular positioning datum. We have devised this datum using a liquid wedge. A ring gauge is chosen as a workpiece to evaluate the deflection behavior of the probing system. The improved uncertainty of the probing is found as low as 40 nm. Subsequently, the inner diameter of the ring gauge is measured on this experimental setup. By employing a simulation, we aligned the workpiece. The deflections of the stylus are optimized to achieve zero deflection error at the zenith points. Consequently, the swing of the probe at the zenith points is combined with the rectilinear displacement of the workpiece to estimate the inner diameter. The uncertainty of the measurement of the ring gauge is improved up to 140 nm.
A pulsed-power implementation of “Laser Gate” for increasing laser energy coupling and fusion yield in magnetized liner inertial fusion (MagLIF)
Authors: Miller S. M. , Slutz S. A. , Bland S. N. , Klein S. R. , Campbell P. C. , Woolstrum J. M. , Kuranz C. C. , Gomez M. R. , Jordan N. M. , McBride R. D.
Published: June 2020

Magnetized Liner Inertial Fusion (MagLIF) at Sandia National Laboratories involves a laser preheating stage where a few-ns laser pulse passes through a few-micron-thick plastic window to preheat gaseous fusion fuel contained within the MagLIF target. Interactions with this window reduce heating efficiency and mix window and target materials into the fuel. A recently proposed idea called “Laser Gate” involves removing the window well before the preheating laser is applied. In this article, we present experimental proof-of-principle results for a pulsed-power implementation of Laser Gate, where a thin current-carrying wire weakens the perimeter of the window, allowing the fuel pressure to push the window open and away from the preheating laser path. For this effort, transparent targets were fabricated and a test facility capable of studying this version of Laser Gate was developed. A 12-frame bright-field laser schlieren/shadowgraphy imaging system captured the window opening dynamics on microsecond timescales. The images reveal that the window remains largely intact as it opens and detaches from the target. A column of escaping pressurized gas appears to prevent the detached window from inadvertently moving into the preheating laser path.
Wave propagation in a nonlocal dispersal SIR epidemic model with nonlinear incidence and nonlocal distributed delays
Authors: Wu Weixin , Zhang Long , Teng Zhidong
Published: June 2020

This paper investigates the traveling wave in a nonlocal dispersal susceptible-infected-removed epidemic model with general nonlinear incidence and nonlocal delayed effects. It is shown that the existence and nonexistence of nontrivial traveling waves are fully determined by the basic reproduction number R0 and critical wave speed c*. When R0>1 and c > c*, the existence of traveling waves is obtained by means of an auxiliary system, the methods of upper-lower solutions, Schauder’s fixed point theorem, and some limiting techniques. When R0>1 and 0 < c < c*, the nonexistence of traveling waves is established by the reduction to absurdity and the theory of asymptotic spreading.
Subwavelength and broadband tunable topological interface state for flexural wave in one-dimensional locally resonant phononic crystal
Authors: Fan Lei , He Ye , Zhao Xue , Chen Xiao-an
Published: June 2020

The topological interface state for an elastic wave in a one-dimensional system, as reported in the literature, mainly occurs through Bragg scattering, making it difficult to achieve subwavelength wave control and flexible tunability. Here, inspired by the band-folding mechanism, this paper confirms that an interface state can likewise be excited by local resonance. The topological phase transition is accomplished by purposely arranging the locations of local resonators. The system is composed of a uniform thin beam with periodically attached local resonators made from an electrorheological elastomer subjected to adjustable electric fields. By simply doubling the primitive unit cell, the passing bands in the dispersion relation are folded and a folding point falls below the locally resonant bandgap, which can be lifted up by simply tuning the distance between two local resonators to realize a topological phase transition. Furthermore, we demonstrate the dynamic tunability of the working frequency of the topological interface state by using an external electric field to adjust the starting frequency of the local resonance. Since the excited frequency of the interface mode is lower than the resonance frequency, this work overcomes the ineffectiveness of the Bragg topological phononic crystal at low frequencies. Moreover, the use of an electroactive resonator whose parameters are readily tuned also enables the flexible design of a frequency-variable topological system without requiring a geometrical modification of the base structure. This technique may have potential applications, such as vibration isolation or in fabricating a robust waveguide.
Tunable and nonlinear metamaterials for controlling circular polarization
Authors: Konishi Kuniaki , Kan Tetsuo , Kuwata-Gonokami Makoto
Published: June 2020

Controlling polarization using metamaterials has been one of the research areas that attract immense attention. In particular, the symmetry of the structure plays an important role in controlling polarization-sensitive optical phenomena. Circular polarization control, which is used for important applications such as circular dichroism spectroscopy, requires designing the symmetry of a metamaterial with circular polarization eigenstates. In the linear response, a giant optical activity was observed in chiral metamaterials. It is possible to actively tune the magnitude and sign of polarization by external stimuli or deforming the chiral metamaterial. Furthermore, in the nonlinear optical response, the metamaterial having the rotational symmetry enables wavelength conversion of circularly polarized light and also controls the phase thereof. This article provides an overview of these previous achievements on the metamaterials for controlling circular polarization with isotropic linear response. The article also discusses the prospects of these technologies that will enable polarization control, not only in the visible region but also in the long-wavelength (terahertz) and extremely short-wavelength (vacuum ultraviolet and extreme ultraviolet) regions in combination with the two advanced technologies: high-order harmonic generation and microelectromechanical systems.
A study on attenuation process of C-C composite material electron beam diode cathode plasma via 12 framing camera
Authors: Wang Tengfang , Zhao Guangyi , Huang Hua , Liu Zhengbang , Jin Xiao , Li Shifeng , Peng Shuming , Lin Jiawen
Published: June 2020

An experimental study of the intense current electron beam diode with a foil-free annular C–C composite material cathode is carried out, the attenuation process of cathode carbon ions at different axial magnetic fields is acquired using an ultrahigh speed 12 framing camera, and the attenuation characteristics of cathode plasma under different discharging voltage waveforms have also been studied. The experiment results show that with the increase in the magnetic field, the force of the axial magnetic field on the electron beam becomes stronger, and the spatial distribution of the Cherenkov radiation light, which is generated by the electron beam bombarding the observation window, decreases. Meanwhile, if the axial magnetic field is less than 0.46 T, the cathode carbon ions have disappeared before reaching the anode. When the axial magnetic field is greater than 0.46 T, the cathode carbon ions move to the anode and then disappear in the vicinity of the anode. A rough estimate shows that the axial diffusion velocity of the cathode carbon ions is about 1.94 cm/μs. In addition, if the discharging voltage waveform has a kickback positive voltage, the carbon ions will diffuse rapidly in the radial direction.
Nonlinear evolution of interacting sinuous and varicose modes in plane wakes and jets: Quasi-periodic structures
Authors: Mikhaylov Kirill , Wu Xuesong
Published: June 2020

A plane wake or jet supports sinuous and varicose instability modes. The nonlinear interaction between them following their linear development was described previously by Leib and Goldstein [“Nonlinear interaction between the sinuous and varicose instability modes in a plane wake,” Phys. Fluids A 1, 513–521 (1989)] using the strongly nonlinear non-equilibrium critical-layer approach in the case of the Bickley jet for which the frequencies of the sinuous and varicose modes have an integer ratio of 2. This paper develops the theory for general profiles where the frequencies of the sinuous and varicose modes are non-commensurable. The disturbance is quasi-periodic in time and space and must be expressed as a function of two phase variables. Using matched asymptotic expansions simultaneously with the multi-scale method, we derived a set of coupled evolution equations governing the development of the amplitudes and critical-layer vorticities of these modes. The evolution system is solved for the base-flow profiles mimicking those in experiments. The sinuous mode suppresses the varicose mode but also causes the latter to saturate in a highly oscillatory manner. The varicose mode inhibits the sinuous mode initially. However, in the later stage, it lends the sinuous mode a significantly higher saturating amplitude. For a wide range of initial modal compositions and Reynolds numbers, the ratio of the varicose mode amplitude to that of the sinuous mode eventually tends to an almost constant value in the range of 0.4–0.6, in line with the experimental measurement. Due to the self and mutual interactions, the vorticities roll up to form vortices, which are non-symmetric in the transverse direction and quasi-periodic in the streamwise direction as well as in time. With such an increased complexity, the vortices resemble those observed in experiments. The nonlinear interactions of the sinuous and varicose modes in the critical layer generate all harmonics in the main layer, as a result of which the perturbation is non-periodic and may even appear “random-like.”
Spectral analysis of the Schrödinger operator with a PT-symmetric periodic optical potential
Authors: Veliev O. A.
Published: June 2020

In this paper, we give a description of the spectral analysis of the Schrödinger operator L(q) with the potential q(x) = 4 cos2 x + 4iV sin 2x for all V > 1/2. First, we consider the Bloch eigenvalues and spectrum of L(q). Then, we investigate spectral singularities and essential spectral singularities (ESS). We prove that there exists a sequence V2 < V3 < ⋯ such that the operator L(q) has no ESS and has ESS, respectively, if and only if V ≠ Vk and V = Vk for k ≥ 2, where Vk → ∞ as k → ∞, V2 is the second critical point. Using ESS, we classify the spectral expansion in term of the points Vk for k ≥ 2. Finally, we discuss the critical points Vk, formulate some conjectures, and describe the changes in the spectrum of L(q) when V changes from 1/2 to ∞.
Resistance of velocity slip flow in pipe/channel with a sudden contraction
Authors: Sun Qiangqiang , Choi Kwing-So , Zhao Yong , Mao Xuerui
Published: June 2020

A novel approach based on the local entropy generation rate, also known as the second law analysis (SLA), is proposed to compute and visualize the flow resistance in mass transfer through a pipe/channel with a sudden contraction component (SCC) at low Reynolds number (Re) featuring velocity slip. The linear Navier velocity slip boundary condition is implemented using the explicit scheme. At small Reynolds number, i.e., Re ≤ 10.0, the flow resistance coefficient of the SCC, KSCC, is found to be a function of the dimensionless velocity slip length Lslip* and Re−1, and gradually increase to a constant value at contraction ratio Rarea ≥ 8, reaching a formula KSCC=(0.4454Lslip* 3−1.894Lslip* 2+2.917Lslip*+8.909)/Re. Over this range of Re, the equivalent length of the flow resistance is almost independent of Re, while out of this range, the equivalent length increases monotonically with Re. Moreover, the dimensionless drag force work around the SCC is negative and reaches a minimum at a critical Lslip*. The SLA reveals that the regions affected by the SCC mainly concentrate around the end section of the upstream pipe/channel rather than the initial partition of the downstream section reported in large Re turbulent flow, and this non-dimensional affected upstream length increases with Lslip*. The fluid physics are further examined using SLA to evaluate the energy loss over the entire domain, decomposed as the viscous dissipation inside the domain and the drag work on the wall boundary.
Design and analysis of 2-bit matrix-type coding metasurface for stealth application
Authors: Yang Jiaji , Li Yinrui , Cheng Yongzhi , Chen Fu , Luo Hui , Wang Xian , Gong Rongzhou
Published: June 2020

Aimed at broadband microwave absorption, we present the linear polarization conversion metasurface (MS) by a novel design of a two-bit matrix-type coding method. The coding patterns are applied to a dielectric substrate and a magnetic substrate. The radar cross section (RCS) reduction curves of different matrices can fully verify the independence and correctness of the matrix-type coding method. As shown in simulation, the RCS reduction of 8 dB by a metal pattern with a dielectric layer has been achieved in the frequency range of 6–15 GHz. When the matrix-type coding pattern is placed in the middle of double-layered magnetic absorbing materials (MMs), a 10 dB RCS reduction can be achieved in the range of 8–16 GHz. Besides, the metal patterns can improve the high frequency reflection loss performance and broaden the absorption bandwidth of MMs almost without changing the thickness. The experimental results can nicely reproduce the simulated results. The correlative RCS reduction mechanism is further explored. This model provides a new idea in the design of coding MS, which implicates a potential application in stealth technology.
A new insight on a mechanism of airborne and underwater sound of a drop impacting a liquid surface
Authors: Gillot G. , Derec C. , Génevaux J.-M. , Simon L. , Benyahia L.
Published: June 2020

We report on an experimental study of the impact of a water drop on a liquid surface in the regime of the so-called irregular entrainment. The hydrodynamics of the phenomenon has been correlated finely to the features of the acoustic signal, both underwater and in the air, thanks to the synchronization of images and sounds in a home-made setup. If the origin of the acoustic signal is known to be caused by the capture of a bubble during the hydrodynamic flow following the impact, for the first time, a new mechanism responsible for the formation of the air bubble is highlighted. The latter is caused by the closing, like a liquid zipper, of the cavity induced by the retraction of the Rayleigh jet, by a secondary droplet detached from this jet. The comparison of the experimental data with the Minnaert model and plane wave theories reveals: (i) the time-dependence of the instantaneous oscillation frequency, (ii) a dominant frequency about 30% higher than the Minnaert prediction, (iii) a higher damping characteristic time, and (iv) a two orders of magnitude higher water–air transmission coefficient. All these results can be explained by the proximity of the bubble to the air–water interface, and by the too small dimensions of the tank to avoid underwater echoes in the measured underwater signal.
Influence of liquid properties on the oblique splashing threshold of drops
Authors: Aboud Damon G. K. , Wood Michael J. , Kietzig Anne-Marie
Published: June 2020

This report investigates how different splashing mechanisms affect the oblique splash threshold of drops impacting a dry solid surface. The splashing behaviors of water, ethanol, and a water/ethylene glycol solution are observed over a wide range of drop diameters (0.7 mm < D < 2.2 mm) and Weber numbers (10 < We < 1040), and several published models are tested in order to predict the thresholds between deposition, one-sided splashing, and two-sided splashing. We found that the splash threshold of liquids that exhibit the corona splashing mechanism can be readily predicted by existing models. However, for liquids such as water that exhibit prompt splashing, the oblique splash threshold is not successfully predicted by any presently established correlation. Hence, our findings identify a critical knowledge gap in the drop impact field, since the behavior of water is of fundamental importance to countless engineering problems. Finally, combining our own results with others reported in the literature, we address some contradictory reports about the influence of liquid viscosity on the splash threshold and demonstrate that the presence or lack of thin-sheet in different experiments could explain the contradictions present in the literature.
Characterization of the non-covalent docking motif in the isolated reactant complex of a double proton-coupled electron transfer reaction with cryogenic ion spectroscopy
Authors: Perez Evan H. , Menges Fabian S. , Cattaneo Mauricio , Mayer James M. , Johnson Mark A.
Published: June 2020

The solution kinetics of a proton-coupled electron transfer reaction involving two-electron oxidation of a Ru compound with concomitant transfer of two protons to a quinone derivative have been interpreted to indicate the formation of a long-lived intermediate between the reactants. We characterize the ionic reactants, products, and an entrance channel reaction complex in the gas phase using high-resolution mass spectrometry augmented by cryogenic ion IR photodissociation spectroscopy. Collisional activation of this trapped entrance channel complex does not drive the reaction to products but rather yields dissociation back to reactants. Electronic structure calculations indicate that there are four low-lying isomeric forms of the non-covalently bound complex. Comparison of their predicted vibrational spectra with the observed band pattern indicates that the C=O groups of the ortho-quinone attach to protons on two different –NH2 groups of the reactant scaffold, exhibiting strong O–H–N contact motifs. Since collisional activation does not lead to the products observed in the liquid phase, these results indicate that the reaction most likely proceeds through reorientation of the H-atom donor ligand about the metal center.
Economic and social consequences of human mobility restrictions under COVID-19
Authors: Bonaccorsi Giovanni , Pierri Francesco , Cinelli Matteo , Flori Andrea , Galeazzi Alessandro , Porcelli Francesco , Schmidt Ana Lucia , Valensise Carlo Michele , Scala Antonio , Quattrociocchi Walter , Pammolli Fabio
Published: June 2020

Significance

This paper presents a large-scale analysis of the impact of lockdown measures introduced in response to the spread of novel coronavirus disease 2019 (COVID-19) on socioeconomic conditions of Italian citizens. We leverage a massive near–real-time dataset of human mobility and we model mobility restrictions as an exogenous shock to the economy, similar to a natural disaster. We find that lockdown measures have a twofold effect: First, their impact on mobility is stronger in municipalities with higher fiscal capacity; second, they induce a segregation effect: mobility contraction is stronger in municipalities where inequality is higher and income per capita is lower. We highlight the necessity of fiscal measures that account for these effects, targeting poverty and inequality mitigation.
Syntheses of all eight stereoisomers of conidendrin
Authors: Shirakata Hinako , Nishiwaki Hisashi , Yamauchi Satoshi
Published: June 2020

All eight stereoisomers of conidendrin were synthesized from (1 R,2 S,3 S)-1-(4-benzyloxy-3-methoxyphenyl)-3-(4-benzyloxy-3-methoxybenzyl)-2- hydroxymethyl-1,4-butanediol ((+)-4) and its enantiomer with high optical purity. The configurations at 4-positions of the conidendrin stereoisomers were constructed by intramolecular Friedel-Crafts reaction of protected 4. After conversion to tetrahydronaphthalene intermediate 7a, the 2- and 3-position of tetrahydronaphthalene structure 7a were converted to 3a- and 9a-position of (+)-α-conidendrin (3a), respectively. By the epimerization process of 2- or 3-position of 7a, the other diastereomers were obtained. All enantiomers were also synthesized from (−)-4.
Load‐velocity relationship of the deadlift exercise
Authors: Morán‐Navarro Ricardo , Martínez‐Cava Alejandro , Escribano‐Peñas Pablo , Courel‐Ibáñez Javier
Published: June 2020

Velocity‐based training (VBT) is gaining popularity in strength and conditioning due to multiple practical advantages for auto‐regulating and individualizing training volume and load on a day‐to‐day basis. Because the load‐velocity relationship varies among exercises, the knowledge of particular equations is indispensable to effectively implement the VBT. The aim of this study was to determine the complete load‐ and power‐velocity profile of the deadlift exercise to provide practical equations and normative values for resistance training coaches and practitioners. Twenty strength‐trained men performed a progressive loading test at maximal intended velocity to determine their one‐repetition maximum (1RM). Mean (MV), mean propulsive (MPV) and peak velocity (PV) were measured during the concentric phase. Both MV and MPV showed a very close relationship to %1RM (R2 = 0.971 and R2 = 0.963) with a low error of estimation (SEE = 0.08 and 0.09 m·s−1), which was maintained throughout the wide breadth of velocities. PV showed the poorest results (R2 = 0.958, SEE = 0.15 m·s−1). MV attained with the 1RM was 0.24 ± 0.03 m·s−1 and consistent between participants with different relative strengths. The load that maximized the power output was identified at ∼60% 1RM. In contrast to what was observed in velocity, power outcomes showed poor predictive capacity to estimate %1RM. Hence, the use of velocity‐based equations is advisable to monitor athletes’ performance and adjust the training load in the deadlift exercise. This finding provides an alternative to the demanding, time‐consuming and interfering 1RM tests, and allows the use of the deadlift exercise following the VBT principles.
Full realization principle for the identification of ideational grammatical metaphor: nominalization as example
Authors: Yang Bingjun
Published: June 2020

When a clause likeglass cracks more quicklyis rankshifted and nominalized asglass crack growth rate, ideational grammatical metaphor (IGM) occurs. However, embedded clauses (e.g. the factthat it had been shown to be aforgery ruined his argument) are also rankshifted and nominalized, but they cannot be regarded as IGMs. This issue of embedding has tended to be relatively under studies within the theory of systemic functional linguistics (SFL). In order to tackle this issue, we propose a principle (i.e. the full realization principle, FRP) which operates in parallel with the principle of rankshift for the identification of IGMs. Under the FRP principle, a nominalization may be full, intermediate or raw in realization, but only the full nominalization which is compressed both in meaning and form can be regarded as IGM. As a necessary supplement to the rankshift principle, FRP helps distinguish nominalizations which are IGMs from those which are not, and the issue of embedding will not be a problem any longer. This in turn offers a new perspective to the categorization of nominalization in general.
Direct polymer microcantilever fabrication from free-standing dry film photoresists
Authors: Nilsen Madeleine , Dannberg Oliver , Fröhlich Thomas , Strehle Steffen
Published: June 2020

Traditionally, polymeric microcantilevers are assembled by a multitude of process steps comprising liquid spin-coated photoresists and rigid substrate materials. Polymer microcantilevers presented in this work rely instead on commercially available dry film photoresists and allowed an omittance of multiple fabrication steps. Thin, 5 μm thick dry film photoresists are thermally laminated onto prepatterned silicon substrates that contain AFM compatible probe bodies. Partially suspended dry film resists are formed between these probe bodies, which are patterned to yield microcantilevers using conventional photolithography protocols. A limited amount of thermal cycling is required, and sacrificial probe-release layers are omitted as microcantilevers form directly through resist development. Even 1 mm long polymeric cantilevers were fabricated this way with superior in-plane alignment. The general effects of post-exposure bake (PEB) and hardbake protocols on cantilever deflection are discussed. Generally, higher PEB temperatures limit out-of-plane cantilever bending. Hardbake improved vertical alignment only of high-PEB temperature cantilevers, while surprisingly worsening the alignment of low-PEB temperature cantilevers. The mechanism behind the latter is likely explained by complex interactions between the resist and the substrate related to differences in thermal expansion, heat conduction, as well as resist cross-linking gradients. We present furthermore multilayer structures of dry film resists, specifically cylindrical dry film resist pillars on the polymer cantilever, as well as the integration of metal structures onto the polymer cantilever, which should enable in future integrated piezoresistive deflection readout for various sensing applications. Finally, cantilever spring constants were determined by measuring force–displacement curves with an advanced cantilever calibration device, allowing also the determination of both, dry film resist cantilever density and Young’s modulus.
Galactose-based polymer-containing phenylboronic acid as carriers for insulin delivery
Authors: Zhong Yunhua , Song Bo , He Dan , Xia Zemei , Wang Peng , Wu Junzi , Li Yan
Published: June 2020

The galactose-based polymer is a promising drug delivery material. Herein, a new galactose-based block copolymer, termed as 6-O-vinyl sebacic acid-D-galactopyranosyl ester block 3-acrylamide phenylboric acid p(OVNG-b-AAPBA) was successfully synthesized by ‘block copolymer’ method. The structure of p(OVNG-b-AAPBA) was proved by nuclear magnetic hydrogen spectrum (1 HNMR) and infrared (IR), the thermal stability was observed by thermogravimetric analyzer, and the molecular weights (Mw and Mn) were demonstrated by Gel permeation chromatography (GPC). The above test results suggested that the polymer of p(OVNG-b-AAPBA) was successfully synthesized, and it had optimal molecular weight and thermal stability, which could be used for investigating the drug delivery system. Then, this block copolymer was prepared to the nanoparticle (NP), these NPs had a satisfactory morphology, and their safety was verified by MTT and chronic animal toxicology test. In addition, insulin was encapsulated by the p(OVNG-b-AAPBA) NPs, the drug loading rate and encapsulation efficiency increased with that of AAPBA in the polymer. Finally, this study confirmed that these NPs can effectively maintain the blood sugar of diabetic mice at 96 h. In conclusion, the current study suggested that the insulin-loaded galactose-based polymer-block-3-acrylamide phenylboric acid NPs had slow-release/glucose-responsive drug release performance, which might play an active role in the diabetes therapy.
Shunted magnetostrictive devices in vibration control
Authors: Deng Zhangxian , Scheidler Justin J , Asnani Vivake M , Dapino Marcelo J
Published: June 2020

Structural vibrations in rotating machinery may lead to imprecise motion control, excessive noise, or even structural damage. Magnetostrictive materials can dissipate unwanted vibrations via hysteresis, eddy currents, and joule heating while exhibiting an electrically-tunable elastic modulus. Harnessing this feature, this article presents a shunted magnetostrictive device that includes an iron-gallium (Galfenol) rod, a permanent magnet array, a flux return path, and shunt circuits. The stiffness tunability and damping of this passive device are measured under a 750 Hz sinusoidal axial compression for resistive, capacitive, and inductive shunt circuits. The effect of eddy currents stiffness and damping is investigated for the first time by comparing results from laminated and solid Galfenol rods. Solid Galfenol produces larger eddy current-based damping, while laminated Galfenol enables larger stiffness variation and total damping. This device demonstrates a power density of 19.83 mW cm−3 for vibration energy harvesting. The frequency-dependent behavior of the shunted device is tested from 5 Hz to 1 kHz for selected electrical loads.
Weyl points and topological surface states in a three-dimensional sandwich-type elastic lattice
Authors: Ganti Sai Sanjit , Liu Ting-Wei , Semperlotti Fabio
Published: June 2020

Following the realization of Weyl semimetals in quantum electronic materials, classical wave analogues of Weyl materials have also been theorized and experimentally demonstrated in photonics and acoustics. Weyl points in elastic systems, however, have been a much more recent discovery. In this study, we report on the design of an elastic fully-continuum three-dimensional material that, while offering structural and load-bearing functionalities, is also capable of Weyl degeneracies and surface topologically-protected modes in a way completely analogous to its quantum mechanical counterpart. The topological characteristics of the lattice are obtained by ab initio numerical calculations without employing any further simplifications. The results clearly characterize the topological structure of the Weyl points and are in full agreement with the expectations of surface topological modes. Finally, full field numerical simulations are used to confirm the existence of surface states and to illustrate their extreme robustness towards lattice disorder and defects.
Mobility analysis of Modified Proportional Fair scheduler in LTE/LTE-Advanced system
Authors: Johal M S , Ismail M K , Hendra H A
Published: June 2020

Packet scheduling is one of the key schemes used in Radio Resource Management (RRM) for Long Term Evolution (LTE) cellular network. It serves as the resource allocation for each time and frequency dimensions in LTE baseband processing. In previous research, a new scheduling algorithm was developed, namely the Modified-Proportional Fair (PF) scheduler that splits a single subframe into multiple time slots and allocates the resource block (RB) to the identified User Equipment (UE) in some chosen time slots and it is done continuously for each subframe depending on the instantaneous Channel Quality Indicator (CQI) feedback received from UEs. Results have shown that the Modified-PF scheduler produces the most outstanding overall performance in terms of spectral efficiency and throughput with comparable fairness as compared to other state-of-the-art schedulers, namely, Round Robin and Proportional Fair schedulers. However, the performance of the new scheduler is not analysed in UE mobility scenario. Hence, this research will determine the type of response by the scheduler towards different mobility condition by simulating the throughput and the spectral efficiency of the three schedulers for various UE velocities. It is observed that the Modified-PF again shows significant performance improvement for various mobility condition in terms of average UE throughput and average UE spectral efficiency in both single cell omnidirectional and tri-sector eNodeB. This shows that Modified-PF can be considered as one of the packet scheduling options for the LTE cellular network.
Efficiency ratio optimization on uplink transmission power for Cloud-Based Radio Access Network
Authors: Ilyana Anwar Apandi Nur , Goh Yu Han Kevin
Published: June 2020

With the adoption of fifth generation (5G) wireless network systems into the fourth Industrial Revolution, the data transfer efficiency and speed will see a significantly improvement, which will lead to systems having the ability to provide a real-time information, and a solution to the capacity problem. Cloud-Based Radio Access Network (C-RAN) is the groundwork on which future 5G networks are based on, and it can increase the spectral efficiency and lower the transmission latency. Moreover, the used of C-RAN in future is expected to decrease the capital, operational and maintenance expenses of mobile operators. This study aims to investigate and validate the joint measures of spectral efficiency and latency optimization by using a quantization process of uplink signal at the remote radio head (RRH) of the C-RAN network. The quantization process is used to convert the received radio frequency signal from mobile user equipment into in-phase and quadrature baseband samples. The uplink transmission power and the number of quantization bits are computed in a way that the performance of spectral efficiency and latency of the RRHs are simultaneously optimized. Results shows that the proposed scheme is capable working with the different types of RRH.
New perspectives of a 5G operating model
Authors: Suryanegara Muhammad
Published: June 2020

The way 5G operators manage infrastructure, enterprise and customers will be radically different compared to preceding generations. This paper aims to provide new perspectives on the 5G operating model by presenting a visual guide on how mobile network operators should deliver value to their prospective 5G customers. The model presented enriches the eTOM framework by elaborating on the implications of virtual network operations, the consequences of an mmWave band, the value of the non-human customer, the security concerns, the role of the content provider in a new ecosystem, and the anticipation of the next generation technological platform.
Development of a PZT device-based power-generating shoes for disaster-affected areas
Authors: Tsukagoshi S , Seto K , Hashimoto S , Basari A A
Published: June 2020

A PZT device is an element that generates electric power when an impact is applied by vibration. Currently, PZT devices are installed on the floor near the ticket gates to supply power to station equipment, and on the floor of bridges to turn on LEDs at night. Since the current generated by the PZT device is small, there is a disadvantage that the electric power obtained is small. In this paper, we developed a power-generating shoe using PZT devices for use in disaster-affected areas where power shortages tend to occur. The validity of the developed power-generating shoes is experimentally evaluated under the variation of PZT device, shoes and secondary batteries. At present, the result is that it is possible to charge about 1.5% of mobile phones at the maximum. In order to reduce loss and obtain more power, it is necessary to improve shoes and to build a charge / discharge circuit.
Increasing the input data length of RSA cryptosystem by applying a hybrid lossless data compression algorithm
Authors: Siriboonpipattana Worapat , Soomlek Chitsutha , Seresangtakul Pusadee
Published: June 2020

RSA is a well-known and widely used cryptosystem. One major limitation of RSA is its maximum input length depends on the chosen key size and the selected padding. This paper proposed a hybrid data compression algorithm to increase the input data length to be encrypted by RSA. Firstly, a plain text is compressed by the LZW algorithm. The compressed data is padded. After that, the size of the compressed data is further reduced by using continued fraction. Double-compressed data is, then, used as an input of RSA. When using a combination of continued fraction and LZW algorithm, the results showed that, on average, the input data length is increased by 18.91 per cent. In most cases, the processing time is much better than not doing any compression. In the case of decryption, a cipher text is decrypted by RSA first. The padding is removed. Then, the Euclidean algorithm and LZW are used respectively to restore the original data. The hybrid data compression is not only relieved the limitation of RSA but also enhances the security level.
Machine learning approach for estimating tree volume
Authors: Hajar Mohd Mushar Siti , Sakinah Syed Ahmad Sharifah , Kasmin Fauziah , Hajar Zamah Shari Nur
Published: June 2020

With the forestry and logging activities contributing to 5.6% of the agricultural sector in Malaysia’s 2018 GDP growth, this had thus implied the forest as having a significant role in national growth and the critical need of a precise tree volume estimation. Although regression has been the most common method used for this form of estimation, the expansion of information technology had, however, led to the use of a machine learning technique that is capable of overcoming the issues posed by the regression analysis. In this paper, the estimation of the tree volume was not only conducted via the regression method but had also involved the use of two machine learning techniques, namely the artificial neural network (ANN) and that of the epsilon-Support Vector Regression (ε-SVR). By comparing the root mean square error (RMSE) and standard deviation (SD) values from each of the volume model that had been obtained in this study, the machine learning technique was thus found to have demonstrated a better precision and accuracy level than that of the regression method.
Minimum leakage current optimization on 22 nm SOI NMOS device with HfO2/WSix/Graphene gate structure using Taguchi method.
Authors: Afifah Maheran A H , Firhat E N , Salehuddin F , Mohd Zain A S , Ahmad I , Noor Faizah Z A , Menon P S , Elgomati H A , Roslan Ameer F
Published: June 2020

To acquire the optimal value of the performance parameter, a bilayer graphene with silicon on insulator (SOI) was enhanced and analyzed on 22 nm NMOS device. The device is made of Hafnium Dioxide (HfO2) as a high-k material whereas Tungsten Silicide (WSix) as a metal gate. The Silvaco software ATHENA and ATLAS modules were applied to simulate the fabrication process of virtual devices and to verify the device’s electrical properties accordingly. The Taguchi L9 orthogonal array method was then used to enhance the device process parameters minimum leakage current (ILEAK) according to the International Technology Roadmap Semiconductor (ITRS) specification of 100nA/μm maximum range. The result from smaller-the-better (STB) for ILEAK is then reviewed by the percentage affecting the process parameter. The simulation result shows that the halo tilting angle is the most dominant factor for ILEAK optimization process. The optimized results indicate excellent device performance with ILEAK = 9.29746 nA/µm which is far lower than the prediction.
Gait recognition using histograms of temporal gradients
Authors: Nair Mogan Jashila , Poo Lee Chin , Ming Lim Kian
Published: June 2020

In this paper, we present a gait recognition method using convolutional features and histograms of temporal gradients. The method comprises three stages, namely the convolutional stage, temporal gradient stage and classification stage. In the convolutional stage, the video frames are convolved with a set of pre-learned filters. This is followed by the temporal gradient stage. In this stage, the gradient of each convolved frame in time axis is calculated. Unlike histograms of oriented gradients that accumulate the gradients in the spatial domain, the proposed histogram of temporal gradients encodes the gradients in the spatial and temporal domain. The histogram of temporal gradients captures the gradient patterns of every pixel over the temporal axis throughout the video sequence. By doing so, the feature encodes both spatial and temporal information in the gait cycle. Finally, in the classification stage, a majority voting classification with Euclidean distance is performed for gait recognition. Experimental results show that the proposed method outperforms the state-of-the-art methods.
Water distribution confined in the nanochannel: the impact of the thermal motion of silicon atoms
Authors: Li J P , Li Y S , Wang Z , Wang H C
Published: June 2020

Using molecular dynamics simulations, the impact of the thermal motion of atoms in silicon walls on the water distribution confined in nanochannel has been investigated. The results show that thermal motion of silicon atoms has marginal effect on water distribution when the surface was not charged. However, when the surface is charged, the thermal motion of silicon atoms decreases the adsorbed peak of water molecular, and moves the position of the Na+ ion concentration peak far away from the surface.
A new rear-illuminated vanadium-compensated 4H-SiC photoconductive switches with AlN anti-reflection coating
Authors: Lai K Y , Qi Y L , Lv H J , Qi B , Zhao Y H
Published: June 2020

This paper presents a new rear-triggered vanadium-compensated 4H silicon carbide (4H-SiC) photoconductive semiconductor switch (PCSS) with aluminum nitride (AlN) anti-reflection coating on the back of PCSS device. Characteristics of PCSS are investigated by using semiconductor device simulation software Silvaco-TCAD. The switch substrates were doped with vanadium to make the substrates highly insulated. The on-state performance of the photoconductive switch was tested under pulsed light conditions with a wavelength of 532 nm and an optical power density of 6.8 MW/cm2 at a bias voltage of 2 kV. And the bias voltage was increased from 0 V to 10 kV in the absence of light trigger conditions, and its off-state characteristics were tested. Results show that the electric field strength between electrodes can be reduced by using rear-triggered structure, the switch breakdown voltage is over 80 kV DC, the maximum transient current is about 137 A, and the tail current almost disappears when the pulse light is turned off. In addition, the breakdown voltage of the rear-triggered PCSS to be higher than that of the front-triggered one. After adding AlN anti-reflection coating on the switch, the maximum transient of the switch and the optical utilization efficiency of laser energy are significantly improved, the maximum transient current of the switch was greatly improved from137 A to 150 A, which was increased by about 9.4 %. In addition, the effects of substrate thickness and optical power density on the switching performance were evaluated.
Towards Development a Novel Framework of Web-Based Systems Quality Engineering by the Integration between Information Systems and Software Engineering Theories: Context of Higher Education
Authors: Fadhel Ibrahim Eskandar Ibrahim , Idrus Syed Zulkarnain Bin Syed , Abdullah Mohd Syukri Yeoh , Ibrahim Amani Ali Elmetwaly Ali , Omar Mazni , Khred Ahmed
Published: June 2020

Nowadays systems failure is the dominant of current research in the fields of information systems and software engineering. The rate of systems fails, and dissatisfying users are high with a lack of appropriate framework that can be used as a success measure in the context. With mix of the results in systems success measure. The organization is in need for a well-defined engineered framework to assist in the success measure of web-based systems. Yemeni south region’s universities are facing the problem (dissatisfying users, justifying the cost of implementing systems and measuring its success). This study aims to propose the characteristics of a quality framework suitable for such a purpose and context of developing a novel systems quality framework based on adapting Delone & Maclean 2003, ISO 25010 and Tam to measure the success and quality of these web-based systems. Researchers validated the framework and instrument via 8 academic specialized lecturers in systems and software engineering from (Malaysia, Yemen and India). Researchers then confirmed the translated questionnaire (English to Arabic and back to back translation) with an authorized translation company. Before starting the pilot study, pre-test has been conducted with nine respondents to see if there is any doubts or unclear syntax, everything was OK. Pilot results showed an excellent result.
The Analysis of Noize Hazard towards Workers in Booster Pump Location of PDAM Tirtanadi Medan, Indonesia
Authors: Sutrisno  , Hasibuan Chalis Fajri , Munthe Sirmas , Banjarnahor Marali
Published: June 2020

The noise sound can be potentially arisen by the usage of machine and work tools that support the production process. PDAM Tirtanadi is a company runs provincial water supply engaged in the drinking water processing. However, the machine and tools of the company can generate the noise. Thus, the paper aims to find out the noise intensity of 5 points measurement in booster pump, then determines the correlation towards communications disruption, psychology and physiology. Then, the sound pressure level measurement method refers to Indonesian Minister of the Environment Decree Number 48 Year 1996, and the sound level meter was utilized as means for the research. The result shows that the noise intensity gained of 5 points passed the noise Threshold Limit Value (TLV) as much 96.40dB – 96.75dB. Moreover, the noise level has a significant influence towards the communications, psychology and physiology disruption, which the R value of multiple correlation as much as 0.884.