bluuebunny/crossref_metadata_2025 huggingface dataset:
Dense binary Fe–Cu sites promoting CO2utilization enable highly reversible hybrid Na–CO2batteries
Authors: Xu Changfan , Zhan Jing , Wang Huanwei , Kang Yao , Liang Feng
Published: August 2021

Dense binary Fe–Cu sites promoting CO2utilization enable ultra-low-voltage gap and ultra-long life hybrid Na–CO2batteries.
Immediate soft-tissue adhesion and the mechanical properties of the Ti–6Al–4V alloy after long-term acid treatment
Authors: Wang Yaming , Okada Masahiro , Xie Shi Chao , Jiao Yu Yang , Hara Emilio Satoshi , Yanagimoto Hiroaki , Fukumoto Takumi , Matsumoto Takuya
Published: August 2021

A metallic solid-state adhesive for biological soft tissues was fabricated using Ti–6Al–4V alloys, and the influence of the minor β phase and the small amount of Al in the α phase are reported.
SERS substrate fabrication for biochemical sensing: towards point-of-care diagnostics
Authors: Liu Xiaojia , Guo Jiuchuan , Li Yang , Wang Bo , Yang Shikun , Chen Wenjun , Wu Xinggui , Guo Jinhong , Ma Xing
Published: August 2021

Portable surface-enhanced Raman spectroscopy (SERS) capable of various analytes detection by using well designed/fabricated SERS substrates in a convenient manner shows great advantages and application potentials in biochemical sensing.
A photo and tumor microenvironment activated nano-enzyme with enhanced ROS generation and hypoxia relief for efficient cancer therapy
Authors: Chen Yali , Cai Yujun , Yu Xingsu , Xiao Hong , He Haozhe , Xiao Zecong , Wang Yong , Shuai Xintao
Published: August 2021

Reactive oxygen species (ROS) mediated tumor therapy strategies have exhibited great prospects and attracted increasing attention, among which photodynamic therapy (PDT) has been well-established.
Polarity-dependent solvatochromic properties of thermally activated delayed fluorescence with donor–acceptor constituents under different excitation energies
Authors: Xu Haiyang , Li Shuzhe , Chen Minyu , Xu Yachen , Zhou Pengchao , Zhang Zhen , Liao Yingjie , Wei Bin
Published: August 2021

The polarity-dependent solvatochromic properties of a D–A structure molecule under different excitation energies are reported.
Eu2+ ions as an antioxidant additive for Sn-based perovskite light-emitting diodes
Authors: Wang Xi , Liu Lihua , Qian Zhao , Gao Congcong , Liang Hongyan
Published: August 2021

We introduced Eu2+ ions as the electron donor to provide a reducing environment to suppress the oxidation of Sn2+. Finally, we obtained a pure red (PEA)2SnI4 LED with a high EQE up to 1.48% and a maximum brightness of 221 cd m−2.
Stem cells and regenerative medicine in sport science
Authors: Stewart Claire E.
Published: August 2021

The estimated cost of acute injuries in college-level sport in the USA is ∼1.5 billion dollars per year, without taking into account the cost of follow up rehabilitation. In addition to this huge financial burden, without appropriate diagnosis and relevant interventions, sport injuries may be career-ending for some athletes. With a growing number of females participating in contact based and pivoting sports, middle aged individuals returning to sport and natural injuries of ageing all increasing, such costs and negative implications for quality of life will expand. For those injuries, which cannot be predicted and prevented, there is a real need, to optimise repair, recovery and function, post-injury in the sporting and clinical worlds. The 21st century has seen a rapid growth in the arena of regenerative medicine for sporting injuries, in a bid to progress recovery and to facilitate return to sport. Such interventions harness knowledge relating to stem cells as a potential for injury repair. While the field is rapidly growing, consideration beyond the stem cells, to the factors they secrete, should be considered in the development of effective, affordable treatments.
CBASP in der stationären Regelversorgung
Authors: Schultheis Daniela
Published: August 2021

Die Behandlung von Menschen mit chronischer Depression bedarf anderer Schwerpunktsetzungen als die herkömmliche Depressionstherapie. CBASP gilt als erster spezialisierter Ansatz für dieses Störungsbild und setzt den Fokus auf den interpersonellen Bereich sowie die Beziehungsgestaltung. Umso wichtiger erscheint daher die Erweiterung der klassischen Einzeltherapie um ein Gruppenprogramm, was sich ideal im stationären Setting verwirklichen lässt.
Avaliação da influência hormonal em pacientes com fraturas atribuídas a osteoporose
Authors: Malheiros-Souza Danila , Gaia Leonardo Franco Pinheiro , Sousa Fausto Fernandes de Almeida , Favaro Pedro Ivo Ferreira , Rodrigues Virmondes , Rodrigues Denise Bertulucci Rocha
Published: August 2021

Objetivo Avaliar a influência dos níveis hormonais de vitamina D, calcitonina, testosterona, estradiol e paratormônio em pacientes com fratura atribuída a osteoporose, quando comparados com pacientes jovens que tiveram fraturas decorrentes de acidente de alto impacto.

Métodos Foram coletadas amostras de sangue de 30 pacientes idosos com fratura atribuída a osteoporose (T-score ≤ -2,5) (grupo com osteoporose) e 30 amostras de sangue de pacientes jovens que sofreram fraturas decorrentes de acidentes de alto impacto (grupo controle). Foram realizadas dosagem de 1,25-hidroxivitamina D (Kit Diasorin, Saluggia, Italy), calcitonina (Kit Siemens, Tarrytown, NY, USA), testosterona, estradiol e paratormônio (Kit Beckman Couter, Indianapolis, IN, United States) pela técnica de quimiluminescência. Os dados foram inseridos em uma planilha de dados no programa Microsoft Excel (Microsoft Corp., Redmond, WA, EUA) e analisados pelo programa de estatística Statview. Os resultados que apresentaram distribuição não normal foram analisados com métodos não paramétricos. Para análise de variáveis comparando-se os dois grupos, aplicou-se o teste Mann-Whitney. Foi utilizado o teste de correlação de Spearman para a correlacionar os níveis hormonais. Um valor-p >0.05 foi considerado significante. Todas as análises foram feitas comparando gênero e grupos de pacientes com e sem osteoporose.

Resultados Mulheres com osteoporose apresentam níveis significativamente menores de estradiol e vitamina D (p = 0.047 e p = 0.0275), respectivamente. Homens com osteoporose demonstraram níveis significativamente maiores de paratormônio (p = 0.0065). Não houve diferença significativa nos níveis de testosterona e calcitonina.

Conclusão Existem diferenças hormonais entre os gêneros na osteoporose. Em mulheres, níveis significativamente menores de estradiol e vitamina D e, nos homens, níveis significativamente maiores de paratormônio, parecem influenciar na doença.
Beam Profiling of Dental Light Curing Units Using Different Camera-Based Systems
Authors: Rocha Mateus Garcia , Oliveira Dayane , Felix Christopher , Roulet Jean-François , Sinhoreti Mário Alexandre Coelho , Correr Américo Bortolazzo
Published: August 2021

Objective This study aimed to perform the beam profile of dental light-curing units (LCUs) using mirrorless and smartphone cameras and correlate it to a camera-based laser beam profiling system.

Materials and Methods Three LCUs were evaluated (Radii Plus; Bluephase G2; and VALO Cordless). The spectral power of the LCUs was measured by using a spectrophotometer. The light emitted from the LCUs was projected onto a glass diffuser, and the images were recorded by using a mirrorless camera (NEX-F3), a smartphone (iPhone) and a camera-based beam profiler. Bandpass optical-filters were used, and for each LCU, the total spectral power output was integrated to calibrate the images. Statistical analysis was performed by digital image correlation (pixel by pixel) using Pearson’s correlation (α = 0.05; β = 0.2).

Results The beam profile images showed nonuniform radiant emittance and spectral emission distributions across all the LCUs light tip. A strong correlation was found among cameras (Pearson’s r = 0.91 ± 0.03 with 95% confidence interval [CI]: 0.88–0.94 for the NEX-F3 and Pearson’s r = 0.88 ± 0.04 with 95% CI: 0.84–0.92 for the iPhone).

Conclusion The standard Ophir beam profile system presented the most accurate distribution, but the mirrorless and smartphone cameras presented a strong correlation in the irradiance distribution of the beam profile images. Alternative cameras can be used to perform light beam profile of dental LCUs, but caution is needed as the type of sensor, image bit depth, and image processing are important to obtain accurate results.
Comparative Evaluation of Distribution of Stresses in Osseointegrated Crestal and Basal Implant in Zygomatic Region of Maxilla
Authors: Thakur Prakhar , Kalra Tarun , Kumar Manjit , Bansal Ajay , Malik Shefali
Published: August 2021

Aim The aim of this study was to evaluate the distribution of stresses in osseointegrated crestal and basal implant in zygomatic region of maxilla and to identify the preferable implant option for better stress distribution.

Material and Method The present in vitro study was performed to evaluate stress patterns in bone around basal and crestal dental implant under axial and oblique loading in maxillary zygomatic region with the help of a finite element analysis (FEA). To conduct this study, the following materials were used: computer software ANSYS, basal implants with dimensions 3.7 × 10 mm, and crestal implants with dimensions 3.7 x 10 mm. The amount of load transferred on the bone adjacent to the implant in an axial and transverse load of 100 N at 0 and 45 degrees, respectively, was placed on both types of implants. A three-dimensional (3D) scanner was use to generate 3D simulated model of basal and crestal implants. FEA modelling was generated that replicated the zygomatico maxillary region with special emphasis on bone architecture, bone density, angulation, width, and length of implant prototype. Further, material properties were defined for cortical bone, dense trabecular bone, low density trabecular bone, and titanium on the basis of Young’s modulus of elasticity.

Results These values were used by FEA software (ANSYS) to generate a 3D mesh model of bone and implant. Finally, Von Mises (equivalent stress) (MPa) values on the implant were computed using FEA software. The values of maximum Von Mises equivalent stress on the implant collars, body, apex, and bony interface were obtained.

Conclusion Maximum stresses were seen at the cortical bone with basal implant placed inside the bone. Stresses that are transferred more to the bone through implant promote bone remineralization. Maximum Von Mises stresses were observed on basal implant body. Thus, these greater stresses have the capacity to simulate mineralization in the cortical bone; this makes basal implant a suitable option for placement inside the cortical bone.
Association of Sociodemographic, Obstetric, and Attitudinal Factors with Prenatal Ultrasound in Mashhad, Iran
Authors: Jarahi Lida , Mahmoudi Rahil , Yazd Mohsen Vazifedar , Ghodsi Hamidreza , Ramezani Mohammad , Omranzadeh Alireza
Published: August 2021

Many antenatal sonographies are out of indication and may be asked due to mothers' requests or other factors. However, these features are not fully understood. This study aimed to assess the association of sociodemographic, obstetric, and attitudinal factors that may affect the number of ultrasound scans. In a cross-sectional study in six hospitals affiliated with Mashhad University of Medical Sciences, 360 mothers who had a delivery or were expected to be near childbirth were enrolled in the study. The mean number of sonographies was compared between different study variables by using Mann–Whitney, Kruskal–Wallis, and Pearson's Chi-squared tests. Moreover, the Spearman Rho test was used to assess the correlation between different variables and the number of sonographies. Totally, 300 cases remained in the study. The mean age of the mothers was 25.95 ± 4.77 years, and the average number of ultrasonographies was 3.50 ± 1.35. In case of sociodemographic features, the level of education (r = 0.23; p < 0.001) and several recent miscarriages (r = 0.140; p = 0.01) were correlated with number of sonographies. However, there was no association between maternal age and marriage age with several sonographies (p > 0.05). Furthermore, mothers with higher family income (p = 0.010), those with medical insurance (p = 0.010), those who had male fetuses (p = 0.020), those who were clerk or student (p = 0.003), and those who were not aware of the sonography risks (p = 0.020) had more requests for sonography. It seems that financial factors and awareness of sonography risks play an essential role in sonography requests by mothers.
SARS-CoV-2 Exposure from Health Care Workers to Infants: Effects and Outcomes
Authors: Shaiba Lana A. , Hadid Adnan , Abdulghani Sahar H. , Hussain Shaikh A. , Shah Prakesh S.
Published: August 2021

Objective This study aimed to evaluate the risk and outcomes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission from positive health care workers (HCW) to infants in the neonatal intensive care unit (NICU) and the postnatal ward.

Study Design We conducted a retrospective analysis of infants in NICU and the postnatal ward postexposure to a COVID-19 positive HCW between May 1 and July 31, 2020. HCW had the detection of SARS-CoV-2 after being symptomatic. Infants exposed to these HCW were tested for SARS-CoV-2 and were classified as confirmed positive when test was positive 24 hours after exposure; confirmed negative when test was negative with no escalation of respiratory support provided; and probable if test was negative. However, infant required escalation of respiratory support. Infants were followed at 14 days postexposure then at the end of the study period for admitted infants.

Results A total of 31 infants were exposed to SARS-CoV-2 positive HCWs (42 exposure incidences). The median age at exposure was 21 days. None of the infants was confirmed positive. Nine infants were classified as probable cases of whom five infants with underlying chronic illnesses died, two were discharged home, and two were still admitted. Of the 22 confirmed negative cases, 15 were discharged and were well on follow-up, and 7 were still admitted.

Conclusion No active transmission of infection from infected HCW to admitted infants was identified. Although some infants had respiratory escalation postexposure none were confirmed positive. Adhering to personal protective equipment by HCW or low susceptibility of infants to SARS-CoV-2 infection may explain the lack of transmission.

Key Points
Thermal transport in defective and disordered materials
Authors: Hanus Riley , Gurunathan Ramya , Lindsay Lucas , Agne Matthias T. , Shi Jingjing , Graham Samuel , Jeffrey Snyder G.
Published: August 2021

With significant recent advancements in thermal sciences—such as the development of new theoretical and experimental techniques, and the discovery of new transport mechanisms—it is helpful to revisit the fundamentals of vibrational heat conduction to formulate an updated and informed physical understanding. The increasing maturity of simulation and modeling methods sparks the desire to leverage these techniques to rapidly improve and develop technology through digital engineering and multi-scale, electro-thermal models. With that vision in mind, this review attempts to build a holistic understanding of thermal transport by focusing on the often unaddressed relationships between subfields, which can be critical for multi-scale modeling approaches. For example, we outline the relationship between mode-specific (computational) and spectral (analytical) models. We relate thermal boundary resistance models based on perturbation approaches and classic transmissivity based models. We discuss the relationship between lattice dynamics and molecular dynamics approaches along with two-channel transport frameworks that have emerged recently and that connect crystal-like and amorphous-like heat conduction. Throughout, we discuss best practices for modeling experimental data and outline how these models can guide material-level and system-level design.
Spheroid-on-chip microfluidic technology for the evaluation of the impact of continuous flow on metastatic potential in cancer models in vitro
Authors: Collins Thomas , Pyne Emily , Christensen Martin , Iles Alexander , Pamme Nicole , Pires Isabel M.
Published: August 2021

The majority of cancer deaths are linked to tumor spread, or metastasis, but 3D in vitro metastasis models relevant to the tumor microenvironment (including interstitial fluid flow) remain an area of unmet need. Microfluidics allows us to introduce controlled flow to an in vitro cancer model to better understand the relationship between flow and metastasis. Here, we report new hybrid spheroid-on-chip in vitro models for the impact of interstitial fluid flow on cancer spread. We designed a series of reusable glass microfluidic devices to contain one spheroid in a microwell under continuous perfusion culture. Spheroids derived from established cancer cell lines were perfused with complete media at a flow rate relevant to tumor interstitial fluid flow. Spheroid viability and migratory/invasive capabilities were maintained on-chip when compared to off-chip static conditions. Importantly, using flow conditions modeled in vitro, we are the first to report flow-induced secretion of pro-metastatic factors, in this case cytokines vascular endothelial growth factor and interleukin 6. In summary, we have developed a new, streamlined spheroid-on-chip in vitro model that represents a feasible in vitro alternative to conventional murine in vivo metastasis assays, including complex tumor environmental factors, such as interstitial fluid flow, extracellular matrices, and using 3D models to model nutrient and oxygen gradients. Our device, therefore, constitutes a robust alternative to in vivo early-metastasis models for determination of novel metastasis biomarkers as well as evaluation of therapeutically relevant molecular targets not possible in in vivo murine models.
Spatiotemporal isotropic-to-anisotropic meta-atoms
Authors: Pacheco-Peña Victor , Engheta Nader
Published: August 2021

Metamaterials and metasurfaces are designed by spatially arranging (periodically or non-periodically) subwavelength geometries, allowing a tailored manipulation of the electromagnetic response of matter. Here, we exploit temporal variations of permittivity inside subwavelength geometries to propose the concept of spatiotemporal meta-atoms having time-dependent properties. We exploit isotropic-to-anisotropic temporal boundaries within spatially subwavelength regions where their permittivity is rapidly changed in time. In so doing, it is shown how resulting scattered waves travel in directions that are different from the direction of the impinging wave, and depend on the values of the chosen anisotropic permittivity tensor. To provide a full physical insight of their performance, multiple scenarios are studied numerically such as the effect of using different values of permittivity tensor, different geometries of the spatiotemporal meta-atom and time duration of the induced isotropic-to-anisotropic temporal boundary. The intrinsic asymmetric response of the proposed spatiotemporal meta-atoms is also studied demonstrating, both theoretically and numerically, its potential for an at-will manipulation of scattered waves in real time. These results may open new paradigms for controlling wave–matter interactions and may pave the way for the next generation of metamaterials and metasurfaces by unleashing their potential using four-dimensional unit cells.
Probing the magnetization switching with in-plane magnetic anisotropy through field-modified magnetoresistance measurement
Authors: Hao Runrun , Zhang Kun , Li Yinggang , Cao Qiang , Zhang Xueying , Zhu Dapeng , Zhao Weisheng
Published: August 2021

Effective probing current-induced magnetization switching is highly required in the study of emerging spin–orbit torque (SOT) effect. However, the measurement of in-plane magnetization switching typically relies on the giant/tunneling magnetoresistance measurement in a spin valve structure calling for complicated fabrication process, or the non-electric approach of Kerr imaging technique. Here, we present a reliable and convenient method to electrically probe the SOT-induced in-plane magnetization switching in a simple Hall bar device through analyzing the MR signal modified by a magnetic field. In this case, the symmetry of MR is broken, resulting in a resistance difference for opposite magnetization orientations. Moreover, the feasibility of our method is widely evidenced in heavy metal/ferromagnet (Pt/Ni20Fe80and W/Co20Fe60B20) and the topological insulator/ferromagnet (Bi2Se3/Ni20Fe80). Our work simplifies the characterization process of the in-plane magnetization switching, which can promote the development of SOT-based devices.
High-performance and fabrication friendly polarization demultiplexer
Authors: Guan Huan , Liu Yang , Li Zhiyong
Published: August 2021

A compact and fabrication friendly polarization demultiplexer (P-DEMUX) is proposed and characterized to enable wavelength-division-multiplexing and polarization-division-multiplexing simultaneously. The proposed structure is composed of a polarization-selective microring resonator in ultrathin waveguide and two bus channels in the silicon nitride-silica-silicon horizontal slot waveguides. In the slot waveguide, the transverse electric (TE) mode propagates through the silicon layer, while the transverse magnetic (TM) mode is confined in the slot region. In the designed ultra-thin waveguide, the TM mode is cut-off. The effective indexes of the TE modes for ultrathin and slot waveguides have comparable values. Thanks for these distinguishing features, the input TE mode can be efficiently filtered through the ultra-thin microring at the resonant wavelength, while the TM mode can directly output from the through port. Simulation results show that the extinction ratio of the proposed P-DEMUX for TE and TM modes are 33.21 dB and 24.97 dB, and the insertion losses are 0.346 dB and 0.324 dB, respectively, at the wavelength of 1551.64 nm. Furthermore, the device shows a broad bandwidth (>100 nm) for an extinction ratio (ER) of >20 dB. In addition, the proposed P-DEMUX also has a good fabrication tolerance for the waveguide width variation of –20 nm ≤ Δ w
g ≤ 20 nm and the microring width variation of –20 nm ≤ Δ w
r ≤ 20 nm for a low insertion loss of <0.75 dB and low ER of <–18 dB.
Electron acceleration during magnetic islands coalescence and division process in a guide field reconnection
Authors: Han Shengxing , Wang Huanyu , Gao Xinliang
Published: August 2021

The magnetic merging process related to pairwise magnetic islands coalescence is investigated by two-dimensional particle-in-cell simulations with a guide field. Owing to the force of attraction between parallel currents within the initial magnetic islands, the magnetic islands begin to approach each other and merge into one big island. We find that this newly formed island is unstable and can be divided into two small magnetic islands spontaneously. Lastly, these two small islands merge again. We follow the time evolution of this process, in which the contributions of three mechanisms of electron acceleration at different stages, including the Fermi, parallel electric field, and betatron mechanisms, are studied with the guide center theory.
Azimuth Control for Large Aperture Telescope Based on Segmented Arc Permanent Magnet Synchronous Motors
Authors: Song Xiao-Li , Wang Da-Xing , Zhou Wang-Ping
Published: August 2021

A tracking control algorithm based on active disturbance rejection controller (ADRC) is proposed to overcome the telescope’s mount fluctuation. The fluctuations are caused by internal and external disturbance when the large aperture telescope runs at ultra-low speed with direct drive. According to the high-precision and high-stability requirements of a large aperture telescope, the ADRC position controller is designed based on segmented arc Permanent Magnet Synchronous Motors (arc PMSMs). The tracking differentiator of ADRC is designed to undergo a transition process to avoid overshoot in the position loop. The speed of target tracking process is observed by the extended state observer and the position information in the system is estimated in real time. The current control variable of the segmented arc PMSM is generated by implementing a non-linear state error feedback control law. The simulation results demonstrate that the proposed control strategy can not only accurately estimate the position and speed of the tracking target, but also estimate the disturbance to compensate the control variables. Experiments showed that the speed error is less than 0.05′ s−1when using the ADRC, and it can realize high tracking performance when compared with PID controller, which improves the robustness of a large aperture telescope control system.
Ice lines as the origin for the gap/ring structure in protoplanetary disks: the issue of the assumed temperature profile
Authors: Liu Yao
Published: August 2021

Gaps and rings are commonly seen in recent high-resolution ALMA observations of protoplanetary disks. Ice lines of volatiles are one of the mechanisms proposed to explain the origin for these substructures. To examine the ice line hypothesis, literature studies usually parameterize the mid-plane temperature with the analytic formula of a passively heated, flared disk. The temperature in this simplified expression is basically dependent on the stellar luminosity. I have built a grid of self-consistent radiative transfer models that feature the same stellar properties, but different disk parameters. The mid-plane temperature of these models shows a large dispersion over a wide range of radii, indicating that besides the stellar luminosity, the disk parameters also play an important role in determining the thermal structure. Comparing the mid-plane temperature from radiative transfer simulation with the analytic solution shows a large difference between both approaches. This result suggests that special care on the assumed temperature profile has to be taken in the analysis of gap/ring origins, and conclusions drawn in previous works on the basis of the analytic temperature should be revisited. I further took the AS 209 disk as an example, and conducted a detailed radiative transfer modeling of the spectral energy distribution and the ALMA Band 6 image. The D137, D24 and D9 gaps are associated with the ice lines of major volatiles in the disk according to such a thorough analysis. However, if the temperature profile simply follows the analytic formula, none of these gaps matches the ice lines of the species considered here.
A new method for resolving phase ambiguity in radio interferometry using Earth rotation synthesis
Authors: Zhou Huan , Xu De-Zhen , Yan Jian-Guo , Chen Shao-Wu , Li Hai-Tao
Published: August 2021

As a key technique in deep space navigation, radio interferometry can be used to determine the accurate location of a spacecraft in the plane-of-sky by measuring its signal propagation time delay between two remote stations. To improve the measurement accuracy, differential phase delay without phase ambiguity is usually desired. Aiming at the difficulties of resolving phase ambiguity with few stations and narrowband downlink signals, a new method is proposed in this work by taking advantage of the Earth rotation. The high accurate differential phase delay between the spacecraft and a calibrator can be achieved not only in the in-beam observation mode but also in the out-of-beam observation mode. In this paper we firstly built the model of phase ambiguity resolution. Then, main measurement errors of the model are analyzed, which is followed by tests and validations of the model and method using the tracking data of the Cassini mission and Chang’E-3 mission. The results show that the phase ambiguities can be correctly resolved to generate a 10-picosecond level accuracy differential phase delay. Angular measurement accuracy of the Cassini reaches the milli-arc-second level, and the relative position accuracy between the Chang’E-3 rover and lander reaches the meter level.
The likely counterpart to γ-ray excess from the northwest region of Arp 220
Authors: Xiang Yun-Chuan , Deng Jun-Hao , Jiang Ze-Jun
Published: August 2021

The unknown γ-ray excess in the northwest region of Arp 220 was revisited by analyzing ∼11.8 years of the Fermi Large Area Telescope (Fermi-LAT) data in this study. We found that its photon flux was approximately three times higher than that of the previous study in the 0.2–100 GeV band, and the corresponding significance level ∼ 8.15σ was approximately four times higher than before. The light curves of 15 and 45 time bins from the whole time all showed two active periods, and the variability of the second period was more significant than that of the first period. The spectral indices from the two active periods were not statistically different and were close to the range of γ-ray flat-spectrum radio quasars observed by Fermi-LAT. Because the position of CRATES J153246+234400 was consistent with the best-fit position of our analysis, we suggest that CRATES J153246+234400 is more likely a γ-ray counterpart for the variational region. For Arp 220, there was no significant variability in the γ-ray emission.
Orbits of 152 globular clusters of the MilkyWay galaxy constructed from Gaia DR2
Authors: Bajkova Anisa Talgatovna , Bobylev Vadim Vadimovich
Published: August 2021

We present orbits and their properties for 152 globular clusters of the Milky Way galaxy obtained using average Gaia DR2 proper motions and other astrometric data from the list of Vasiliev. For orbital integration we have applied the axisymmetric model of the Galactic potential based on the Navarro-Frenk- White dark halo, and modified by Bajkova & Bobylev utilizing circular velocities of Galactic objects in a wide region of Galactocentric distances (up to 200 kpc) from the Bhattacharjee et al. catalog. Based on the analysis of the obtained orbits, we have modified the composition of the subsystems of globular clusters presented in Massari et al.
Expansion series of the pairwise velocity generating function and its implications on redshift space distortion modeling
Authors: Chen Jun-De , Zhang Peng-Jie , Zheng Yi
Published: August 2021

The pairwise velocity generating function G has a deep connection with both the pairwise velocity probability distribution function and modeling of redshift space distortion (RSD). Its implementation into RSD modeling is often faciliated by expansion into a series of pairwise velocity moments

〈

v

12

n

〉

. Motivated by the logrithmic transformation of the cosmic density field, we investigate an alternative expansion into series of pairwise velocity cumulants

〈

v

12

n

〉

c

. We numerically evaluate the convergence rate of the two expansions, with three 30723 particle simulations of the CosmicGrowth N-body simulation series. (1) We find that the cumulant expansion performs significantly better, for all the halo samples and redshifts investigated. (2) For modeling RSD at k
∥ < 0.1h Mpc−1, including only the n = 1,2 cumulants is sufficient. (3) But for modeling RSD at k
∥ = 0.2h Mpc−1, we need and only need the n = 1,2,3,4 cumulants. These results provide specific requirements on RSD modeling in terms of m-th order statistics of the large-scale structure.
The afterglow emission from a stratified jet in GRB 170817A
Authors: Cheng Kang-Fa , Zhao Xiao-Hong , Zhang Bin-Bin , Bai Jin-Ming
Published: August 2021

The afterglow of GRB 170817A has been detected for more than three years, but the origin of the multi-band afterglow light curves remains under debate. A classical top-hat jet model is faced with difficulties in producing a shallow rise of the afterglow light curves as observed (Fν
∝ T
0.8). Here we reconsider the model of stratified ejecta with an energy profile of E(>Γ β) = E
0(Γ β)−k
as the origin of the afterglow light curves of the burst, where Γ and β are the Lorentz factor and speed of the ejecta, respectively. k is the power-law slope of the energy profile. We consider that the ejecta are collimated into jets. Two kinds of jet evolutions are investigated, including a lateral-spreading jet and a non-lateral-spreading jet. We fit the multi-band afterglow light curves, including the X-ray data at one thousand days post-burst, and find that both the models of the spreading and non-spreading jets can fit the light curves well, but the observed angular size of the source and the apparent velocity of the flux centroid for the spreading jet model are beyond the observation limits, while the non-spreading jet model meets the observation limits. Some of the best-fit parameters for the non-spreading jet model, such as the number density of the circumburst medium ∼10−2 cm−3 and the total jet kinetic energy E ∼ 4.8 × 1051 erg, also appear plausible. The best-fit slope of the jet energy profile is k ∼ 7.1. Our results suggest that the afterglow of GRB 170817A may arise from the stratified jet and that the lateral spreading of the jet is not significant.
Recurrence Analysis Applied to Ultrasonic Absorptive Coating
Authors: Martellini Edoardo , Candeloro Paolo , Peng Lv , Pagliaroli Tiziano
Published: August 2021

Metasurfaces are, at the actual state-of-the-art, a constant topic for scientific community as they find widespread applications in several fields, including acoustics and aeroacoustics. In this paper, the potential of recurrence analysis was evaluated by applying it to some metasurfaces. These devices effectiveness has been previously demonstrated with a reflection coefficients analysis in the Fourier and Wavelet domains. A novel strategy based on the Recurrence Analysis, which is a no man’s land applied on the metasurfaces, was performed. The evaluation of the recurrence plot and phase space attractors led to interesting results. The results show an introduction of non linearities after the forcing wave interacts with the metasurfaces. In light of that, there is the evidence that the chaotic analysis principles may be a powerful tool to characterize the performance of metasurfaces in particular through the calculation of the chaotic indexes. This method could be integrated with previous ones for the evaluation of more complex and multiscale geometries that nowadays show huge potential in too many fields of application.
Analisys of particles transportation applied to a ship’s ballast system by using fastcam recorded images
Authors: Amoresano A. , Iodice P. , Langella G. , Mocerino L. , Quaranta F.
Published: August 2021

High-performance imaging techniques represent the present of academic and industrial research. The use of these technologies in the maritime sector sees different applications in different phases of the life of a ship: photogrammetry in the design phase and the use of Lidar sensors to measure emissions are just a few examples. The novelty of this study is the application of these acquisition techniques to ship ballast systems. The new ballast water management regulations aimed at limiting the alteration of the marine ecosystem has overturned the canonical use of the ballast systems. In recent years, studies have shown how the spillage of ballast water has generated the proliferation of invasive species in seas all over the world. For this reason, the IMO has tried to regulate these operations. In this work, transportation phenomena of sediments through the duct, suctioned by a pump have been analysed. The inspected duct has been exposed to a CMOS MINI FASTCAM AX100. This camera was used to acquire images that allow studying the behaviour of the particles. With the use of a Matlab toolbox, a post processing of the images has been realized in order to estimate the speed and accelerations of the particles.
Application of the Gas-Coupled Laser Acoustic Detection technique to non-destructive monitoring of mechanical components
Authors: Gulino Michelangelo-Santo , Bruzzi Mara , Vangi Dario
Published: August 2021

Non-contact ultrasonic techniques are fundamental to devise online monitoring systems for moving or difficult to access structures. Gas-Coupled Laser Acoustic Detection (GCLAD) is an unestablished, non-contact detection technology which relies on measuring the deviation affecting a laser beam when travelling across an ultrasonic wavefront propagating in a fluid. The aim of the work is to provide in-depth highlights on the principles on which the technique leverages, with a view towards how several laser beam and ultrasonic wave features reflects on the signal acquired by the GCLAD device. By numerical and experimental approaches, parameters needing to be specifically addressed and suitably set during the investigation phase are highlighted, which enable amplitude maximization of the acquired signal. Specifically, effect of the probe laser beam spot size is thoroughly analyzed, as well as the mutual orientation between the beam and the ultrasonic propagation directions. Three test configurations are lastly proposed, providing different results in terms of GCLAD sensitivity to the acoustic waves; such differences are highlighted by applying the technique to a railway axle on which an artificial crack has been machined, providing a first assessment of the GCLAD capabilities in the non-destructive testing field.
Evolution of flow structures in twin-rotors wakes in drones by time-resolved PIV
Authors: Nargi Ranieri Emanuele , Gregorio Fabrizio De , Candeloro Paolo , Ceglia Giuseppe , Pagliaroli Tiziano
Published: August 2021

An experimental investigation of the noise emissions of a twin-rotor together with the evolution and spatial organization of the flow structures wakes has been carried out by means of aeroacoustics and time-resolved PIV (TR-PIV) measurements. Each rotor is characterized by three bladed propellers with diameter D = 393.7 mm running at four different rotational speeds (2620, 3500, 4360, 5200 RPM). Intricate flow patterns characterized by periodic vortical structures are formed in the wake of the rotors in twin configuration at the rotor-to-rotor distance of 1.02D. Their interaction determines a strong impact on the aerodynamic performances as well as on the noise generation. Hence, the need for TR-PIV measurements relies on what is the role of these instantaneous flow patterns to unveil the spatial organization and the dynamic behaviour inspected by imaging the region between the rotors. It is found that the flow organization and the interaction between evolution of vorticity intensity of tip vortices characterize the twin-rotors wakes.
Preliminary analysis of the flow field in a transparent model of a SRF cavity by PIV
Authors: Cozzi F , Pianello G , Ambros A D’ , Pagani C , Sertore D
Published: August 2021

Niobium superconductive radio frequency cavities (SRF cavities) are commonly employed in linear accelerator; very pure, clean, and smooth internal walls are required to make the cavity working properly and with a high Q factor. Typically, to achieve a suitable surface quality the SRF cavities are subjected to a surface treatment called Buffered Chemical Polish (BCP), the latter uses a strong concentrated acids mixture flowing through the cavity to chemically etch a thin niobium layer (∼250 μm). A viable way to understand and optimize the BCP process is by using computational fluid dynamic (CFD); however, the experimental validation of the numerical and physical models is required to confidently use CFD results. The aim of our work is to investigate the fluid dynamics of the BCP process by using the Particle Image Velocimetry (PIV) and the refractive index matching (RIM) techniques, and to provide data to validate CFD simulations. The paper describes and briefly analyse the experimental setup and the preliminary results achieved so far.
Preliminary Analysis on Environmental and Intrinsic Factors on FBG-Based Vibration Sensors
Authors: Quattrocchi Gaetano , Dalla Vedova Matteo Davide Lorenzo , Berri Pier Carlo , Maggiore Paolo
Published: August 2021

In recent years, optical-based sensors have sparked interest for the many advantages over traditional, electrical-based sensors, such as EMI insensitivity, ease of multiplexing on a single line, resilience to hostile environment and very compact size and global weight saving due to signal cables reduction. Considering said properties, optical sensors offer a compelling alternative to traditional sensing elements. One type of optical sensor is the Fiber Braggs Gratings sensors (FBG), which is a type of sensor that reflects a very narrow band of wavelengths, called Bragg wavelength, while being transparent for others; this behavior is achieved by local variations of the core refractive index. The Bragg wavelength can be easily correlated with physical changes in the sensor itself, due to either physical strain or temperature variation. It should be noted that the achievable measurement accuracy is thus comparable to the Bragg wavelength. However, for any practical application, FBGs need to be bonded to a support or surface; in this case, there is a lack of understanding of the effects of temperature and humidity variations on the combined sensor-glue system. In this work, a setup, intended to characterize the sensitivity of the fiber-glue combination to humidity and temperature will be presented.
Green Channel and Top Hat based Image Enhancement for Diabetic Retinopathy Screening
Authors: Sharif N A M , Azhar A S M , Harun N H , Bakar J A , Abdullah A A , Chong Y F
Published: August 2021

Diabetic Retinopathy remains one of the most feared diabetes complications that could lead to blindness. Image processing techniques have been widely used all around the world for early detection of diabetic retinopathy. However, most techniques used do not focus on the low visual quality problems in the fundus image. Low visual quality of fundus image may lead to difficulty in evaluation by ophthalmologist before reading it out to the patients. Hence, Automated Screening for Diabetic Retinopathy was created to focus on image enhancement of the fundus image. In this study, two main algorithms for image processing have been used which are green channel conversion and top-hat filters. Green channel in fundus image is selected due to better contrast of the features and background compared to the red and blue channel. While Top-hat filter used to details out small features in the fundus image. The evaluation result of the techniques is compared by using Mean-Squared Error (MSE), Peak Signal-to-Noise Ratio (PSNR) and Entropy calculations to measure quality of the enhanced fundus images. Results of image enhancement techniques implemented has proved that quality of the fundus image is improved.
Analyzing the Factors Affecting the Tollgate Entry/Exit Experience
Authors: Magsino Elmer R.
Published: August 2021

When goods and commodities are transported from source to market, producers/sellers utilize highways and expressways to reduce travel time and avoid damage to perishable goods. One unavoidable experience is when these people reach the tollgate to pay toll fees for using this convenience, especially during peak hours. In this study, the five factors affecting tollgate entry/exit experience are analyzed. The effects of varying one factor at a time are presented and relevant findings are suggested to improve the vehicular entry/exit experience. Extensive simulation runs show that the main contributors of prolonged queue waiting time and increased server utilization are the heavy arrival rate and slow service times. Results also verify that there is an unbalanced formed queues and server utilization among all active tollgates.
Development of a Predictive Analytic Tool for Detection of Alzheimer’s Disease
Authors: Yee Aw Hui , Abdullah Azian Azamimi , Bakar Juhaida Abu
Published: August 2021

Alzheimer’s disease (AD) is the common neurodegenerative disease that causes the impairment of the brain tissue with a gradual decline in the memory and thinking skills among the elderly population. However, there is a lack of reliable biomarker and effective medical treatment to detect and cure the AD respectively. Since there is a commitment agrees that AD should be the focus on the early diagnosis stage due to the great improvement on the treatment efficacy, hence with the help of imaging modality such as Magnetic Resonance Imaging (MRI), it can provide a detailed brain’s features information for analysis and interpretation purposes. Besides that, this project is focusing on the implementation of the supervised machine learning algorithms on the prediction of AD based on the Graphical User Interface (GUI). By referring to the results obtained from classifiers’ performance evaluation, Random Forest achieved the best performance in classification of AD with the highest accuracy of 0.7825 and AUC score of 0.8314 along with Lasso Regularization, followed by Gradient Boosting Machine (GBM) with accuracy of 0.7352 and Deep Neural Network (DNN) with accuracy of 0.6201 only. The machine learning with feature selection, Lasso Regularization is performed much better than those without feature selection. Thus, the GUI is then developed to provide convenience for the user to accurately predict their current AD’s status.
COVID-19 mRNA Vaccine Degradation Prediction Using LR and LGBM Algorithms
Authors: Ing Soon Hwai , Abdullah Azian Azamimi , Harun Nor Hazlyna , Kanaya Shigehiko
Published: August 2021

The threatening Coronavirus which was assigned as the global pandemic concussed not only the public health but society, economy and every walks of life. Some measurements are taken to stifle the spread and one of the best ways is to carry out some precautions to prevent the contagion of SARS-CoV-2 virus to uninfected populaces. Injecting prevention vaccines is one of the precaution steps under the grandiose blueprint. Among all vaccines, it is found that mRNA vaccine which shows no side effect with marvellous effectiveness is the most preferable candidates to be considered. However, degradation had become its biggest drawback to be implemented. Hereby, this study is held with desideratum to develop prediction models specifically to predict the degradation rate of mRNA vaccine for COVID-19. Two machine learning algorithms, which are, Linear Regression (LR) and Light Gradient Boosting Machine (LGBM) are proposed for models development using Python language. Dataset comprises of thousands of RNA molecules that holds degradation rates at each position from Eterna platform is extracted, pre-processed and encoded with label encoding before loaded into algorithms. The results show that LGBM (0.2447) performs better than LR (0.3957) for this study when evaluated with the RMSE metric.
Taxi Hotspots Identification through Origin and Destination Analysis of Taxi Trips using K-means Clustering and H-indexing
Authors: Magsino Elmer R. , Abello Ara Jyllian , Lalusin Joaquin Miguel
Published: August 2021

It is apparent that the taxi industry has grown and developed over the years. In addition to that, it will presumably continue to grow as time goes on due to the increasing popularity of taxi-hailing applications. However, taxi origin and destination (O-D) locations are not clearly established since taxis are very flexible in terms of where they can pick up and drop off passengers. In this study, the taxi origin and destination hotspots are determined by first clustering the available O-D pairs from empirical mobility traces. The validity of these formed clusters is determined by utilizing the silhouette analysis. Finally, hotspots are located by measuring the cluster’s h-index. Simulation results reveal that more clusters tend to provide unreliable silhouette values due to the fact that origin/destination GPS points are very close to each other. For a given number of clusters, the h-index tend to locate clusters that can be considered as hotspots.