bluuebunny/crossref_metadata_2025 huggingface dataset:
Transient analysis of graphene-based on-chip interconnects using closed-form MRA model
Authors: Kumar Amit , Kaushik Brajesh Kumar
Published: April 2021

As interconnects in very-large-scale-integration technology shrinks into the sub-22 nm regime, carbon nanotubes, graphene nanoribbons (GNRs), and Cu-GNRs are emerging as potential replacements for conventional copper on-chip interconnects. This paper presents an matrix-rational-approximation (MRA) model for the fast transient analysis of graphene-based on-chip interconnects. The proposed model’s key feature is that it allows the mathematical representation of the transfer function matrix of on-chip graphene-based interconnect networks in the frequency-domain using closed-form rational functions. The network’s rational functions coefficients are derived from per-unit-length parameters and predetermined coefficients of the Padé approximation. The graphene-based network’s time-domain model is directly obtained from the rational function frequency-domain model without any numerical integration techniques. This makes the proposed MRA model more numerically efficient than conventional simulation program with integrated circuit emphasis (SPICE) models. The results obtained using the proposed model show less than 1% error when compared with HSPICE simulations, ensuring the proposed model’s excellent accuracy. A wide eye-height of 0.8137 V and eye-width of 219.87 ps are obtained for the eye-diagram analysis of multilayer graphene nanoribbon lines at 4 Gbps.
High-speed short-wave infrared Si-based GeSn MQW phototransistor: an alternative to existing photodetectors
Authors: Kumar Harshvardhan
Published: April 2021

This work demonstrates high-performance vertical GeSn multiple quantum well (MQW) heterojunction phototransistors (HPTs) on Si substrates for short-wave infrared (SWIR) applications. Estimated results show a strong dependence on the number of QWs (N), incident optical power

P

in

and capture parameter

β

. Enhanced carrier and gain confinement cause an increase in responsivity of the device with the QWs in the base layer. However, the frequency performance of the device degrades with more QWs due to the increased forward transit time. On the other hand, the 3 dB cut-off frequency

f

T

is the highest for the lower value of

β

. In addition, the detectivity and responsivity of the device decrease with an increase in incident optical power due to the change in base potential. The calculated results show that the 3 dB cut-off

f

T

and maximum operating frequency

f

max

are

>
18

 GHz

and

>
0.147

 THz

, respectively for N = 1 at 300 K. The detectivity and noise equivalent power are

∼

10
9

cm

H

z

1

/

2

/

W

and

<

10

−
12

WH

z

−
1

/

2

, respectively for N = 3 at 300 K under 0.4 applied bias voltage. These promising results of the presented GeSn MQW HPT can pave the way for efficient low-noise high-speed photodetection applications under a low applied bias voltage.
Superconducting nanowire single-photon detector made of ultrathin γ-Nb4N3 film for mid-infrared wavelengths
Authors: Pan Yiming , Zhou Hui , Zhang Lu , Li Hao , Tang Yan , Yu Huiqin , Si Mengting , You Lixing , Wang Zhen
Published: April 2021

Superconducting nanowire single-photon detectors (SNSPDs) made of ultrathin δ-NbN films have been widely applied in both visible and infrared wavelengths. For mid-infrared (MIR) wavelengths, SNSPDs made of tungsten silicide films with a lower critical temperature were reported up to 9.9 μm wavelength. In this study, we demonstrate the potential of NbN-SNSPDs for use in MIR applications. SNSPDs made of γ-Nb4N3 films (critical temperature of 5.1 K for 6.5 nm thick films) instead of δ-NbN films were fabricated. The dependence of the normalized detection efficiency on the bias current indicated a clear trend toward a saturated plateau for wavelengths up to 2145 nm. The calculated cut-off wavelengths indicated the possibility of using γ-Nb4N3 SNSPDs for longer MIR wavelengths.
First-order kinetics bottleneck during photoinduced ultrafast insulator–metal transition in 3D orbitally-driven Peierls insulator CuIr2S4
Authors: Naseska M , Sutar P , Vaskivskyi Y , Vaskivskyi I , Vengust D , Svetin D , Kabanov V V , Mihailovic D , Mertelj T
Published: April 2021

The spinel-structure CuIr2S4 compound displays a rather unusual orbitally-driven three-dimensional Peierls-like insulator–metal transition. The low-T symmetry-broken insulating state is especially interesting due to the existence of a metastable irradiation-induced disordered weakly conducting state. Here we study intense femtosecond optical pulse irradiation effects by means of the all-optical ultrafast multi-pulse time-resolved spectroscopy. We show that the structural coherence of the low-T broken symmetry state is strongly suppressed on a sub-picosecond timescale above a threshold excitation fluence resulting in a structurally inhomogeneous transient state which persists for several-tens of picoseconds before reverting to the low-T disordered weakly conducting state. The electronic order shows a transient gap filling at a significantly lower fluence threshold. The data suggest that the photoinduced-transition dynamics to the high-T metallic phase is governed by first-order-transition nucleation kinetics that prevents the complete ultrafast structural transition even when the absorbed energy significantly exceeds the equilibrium enthalpy difference to the high-T metallic phase.
Generation and coherent control of terahertz acoustic phonons in superlattices of perovskite oxides
Authors: Yang Chi-Yuan , Wu Ping-Chun , Chu Ying-Hao , Lin Kung-Hsuan
Published: April 2021

We utilized transmission-type pump–probe technique to investigate coherent acoustic phonons in the superlattices of perovskite oxides such as SrIrO3/SrTiO3 and SrRuO3/SrTiO3. Because the films in the superlattices are of high-quality and their thicknesses are only several monolayers, quasi-monochromatic acoustic phonons with THz frequency have been achieved. By investigating the propagation of coherent acoustic phonons in the superlattices with different epitaxial periods, the phonon mean free paths of SrTiO3 were studied in the frequency range between 0.5 THz and 1 THz. We further demonstrated coherent control to amplify or cease the THz coherent acoustic phonon oscillations in the superlattices. By controlling the delay of two pulses for shining the superlattices, the amplitude and phase of the THz coherent acoustic phonons were manipulated. According to the measurements of time-domain Brillouin scatterings, we found the optoacoustic conversion efficiency of SrIrO3 outperforms that of SrRuO3 for generating acoustic phonons.
Tunable chiral responses in mechanically reconfigurable three-dimensional metamaterials
Authors: Han Donghai , Fang Xiangdong , Zhang Liuyang , Chen Xuefeng
Published: April 2021

The active manipulation of polarization state is of fundamental importance to functional devices integrated in modern terahertz (THz) systems. The emerging chiral metamaterials (MMs) provide enormous possibilities to control the polarization state of incident THz wave, however, existing MMs with strong chirality are normally insufficient to modulate the circular dichroism (CD). Here, we have proposed a conceptual 3D mechanically reconfigurable chiral MM that is capable of tailoring the right circular polarization transmission and linear-to-circular polarization conversion. The 3D MM morphology can be reproducibly controlled by alternating the pre-strain on the elastic substrate, which allows to provide a flexible route to reconfigure the structural chirality and modulate the chiral response. Additionally, CD spectra exhibit high sensitivity to the rotation angle of MM component. The mechanically tunable chiral MM with high flexibility will build up an efficient approach for the CD enhancement and modulation and paves a novel avenue toward the reconfigurable design principle of flexible functional THz devices.
Performance of liquid-lithium-filled 3D-printed tungsten divertor targets under deuterium loading with ELM-like pulses in Magnum-PSI
Authors: Rindt P. , Korving S.Q. , Morgan T.W. , Lopes Cardozo N.J.
Published: April 2021

A fusion reactor divertor must withstand heat flux densities <10 MW m−2. Additionally, it may have to withstand millisecond pulses on the order of 0.5 to 30 MJ m−2 due to (mitigated) edge-localized modes (ELM) occurring with 30 to 60 Hz. We investigate if these requirements can be met by capillary porous system (CPS) liquid lithium divertors (LLD). 3D-printed tungsten CPS targets were exposed in the linear plasma device Magnum-PSI, to deuterium plasma discharges lasting 15 s, generating 1.5 to 16 MW m−2, and T
e ∼ 1.5 eV. Additionally, ELM-like pulses were superimposed on top of the steady state for 3 s with a frequency of 2 and 100 Hz, power flux densities of 0.3 to 1 GW m−2, and T
e up to ∼14 eV. All Li targets survived without damage. The surface temperature (T
s) was locked at ∼850 °C, which was attributed to power dissipation via vapor shielding. Meanwhile, unfilled reference targets melted during the severest pulsed loading. A blue grayish layer of presumably LiD formed when T
s < 500 °C, but disappeared when the locking temperature was reached. This implies that LiD formation can be avoided, but that it may require a surface temperature at which Li evaporation excessively contaminates the core plasma in a tokamak. During pulsed loading the plasma facing surface remained wetted in all conditions. Bolometry indicated that, only during pulses, there was a large increase in radiative power dissipation compared to targets without Li. A high speed camera with a Li-I filter showed that strong Li evaporation continued up to 5 ms after a pulse. Overall, the liquid-lithium-filled 3D-printed tungsten targets were found to be highly robust, and 3D-printing can be considered as a promising manufacturing technique for LLDs. Further research is needed particularly on the formation of LiD and the associated tritium retention, as well as the impact of enhanced evaporation during and after ELMs on the core plasma.
Theory-based scaling laws of near and far scrape-off layer widths in single-null L-mode discharges
Authors: Giacomin M. , Stagni A. , Ricci P. , Boedo J.A. , Horacek J. , Reimerdes H. , Tsui C.K.
Published: April 2021

Theory-based scaling laws of the near and far scrape-off layer (SOL) widths are analytically derived for L-mode diverted tokamak discharges by using a two-fluid model. The near SOL pressure and density decay lengths are obtained by leveraging a balance among the power source, perpendicular turbulent transport across the separatrix, and parallel losses at the vessel wall, while the far SOL pressure and density decay lengths are derived by using a model of intermittent transport mediated by filaments. The analytical estimates of the pressure decay length in the near SOL is then compared to the results of three-dimensional, flux-driven, global, two-fluid turbulence simulations of L-mode diverted tokamak plasmas, and validated against experimental measurements taken from an experimental multi-machine database of divertor heat flux profiles, showing in both cases a very good agreement. Analogously, the theoretical scaling law for the pressure decay length in the far SOL is compared to simulation results and to experimental measurements in TCV L-mode discharges, pointing out the need of a large multi-machine database for the far SOL decay lengths.
Statistical Analysis of Renewable and Non-renewable Energy Consumption against Population Growth
Authors: Aboueata Walid , Hijawi Ula , Al-Kababji Ayman , Mohieddine Abdulrahman , Choe Pilsung
Published: April 2021

Global population has significantly tripled in the last 50 years. The increasing population rate has led to increasing energy consumption, consequently, increasing Greenhouse Gas (GHG) emissions, which is the leading cause for global warming that endangers survival chances for living species. However, recent interest surged in renewable energy for clean and sustainable power production and consumption. With the deployment of renewable energy in the past years, dependence on fossil fuel was supposed to have declined, and consequently, GHG emissions, especially CO2. The aim of this research is to study the effect of population growth against fossil fuel consumption producing these emissions, in addition to the impact of renewable energy consumption that alternatively reduces GHG emissions. The outcome of the proposed topic represents comprehensive findings that relate population growth with global energy consumption against GHG emissions over the past few decades. This is achieved based on recent statistical applications and methodologies including linear regression models, and prediction models, which are applied to study the interaction of annual CO2 emissions, energy consumption, and population during, almost, the past fifty years. Additionally, according to the results, the presented null hypothesis is rejected as the current trend does not comply with the Paris agreement.
Dynamic Time Analysis of the Composite Shear Wall on the Grid-tube-type Double Steel Plate Wall with Infilled Concrete
Authors: Li Biqing , Li Jinbao , Xu Wenping
Published: April 2021

In this paper, based on a 30-story building with frame-core tube structure system, three comparative schemes are established of reinforced concrete core tube construction, steel-reinforced concrete core tube construction and the combined shear wall core tube structure with the grid-tube-type double steel plate wall with infilled concrete are established, and the dynamic elastoplastic time history is analyzed. Research shows that under the influence of a severe earthquake, the lateral strength degradation and stiffness degradation are slow on the Joint structural system of concrete filled steel tubular frame and composite shear wall core tube structure with the grid-tube-type double steel plate wall with infilled concrete, so interlayer shear force and bottom shear force increase, structural lateral stiffness increased significantly, interlayer displacement angle reduces significantly, and it improves the seismic performance of tall building.
Plane Accuracy of Aerophotogrammetry without Image Control Points of DJI PHANTOM 4 RTK UAV
Authors: Xiu Chun , Li Zhengxu , Duan Haiqin , Lu Xin , Ma Tianran , Shan Chunzhi
Published: April 2021

The small unmanned aerial vehicles (UAVs) have good operability, low cost and high production efficiency in the low-altitude aerophotogrammetry. In this paper, the checkpoint coordinate data of low-altitude aerophotogrammetry from DJI PHANTOM 4 RTK UAV in the image-free controlled model are compared with the measured data of GNSS RTK. The results show that the maximum errors of the plane coordinates of checkpoints extracted by UAV were 0.067 m and 0.045 m in X-direction and Y-direction respectively and the plane mean square error (PMSE) was ± 0.051 m, which meet the rules of the national standard and industrial standard. Therefore, the low-altitude aerophotogrammetry of DJI PHANTOM 4 RTK UAV without the image control points can be effectively applied to large-scale surveying and mapping in small areas.
Research on the Leap Second Adjustment Methods in BDS
Authors: Cheng Mengfei , Xue Shenhui , Wang Yupu , Li Boyu
Published: April 2021

Since July 31st 2020, BDS-3 provides service formally, in the open service, BDS-3 reserves old type signals B1I\B3I in BDS-2, and adds new type signals B1C\B2a\B2b. Because users misunderstand how to work out the leap second, some user terminals didn’t successfully complete BDT to UTC on June 30st 2015 and 31 December 31st 2016 in time in BDS-2. Compared with BDS-2, BDS-3 has not experience leap second yet, this paper introduces the leap second process in BDS-3 Radio Navigation Satellite Service (RNSS), explains the meanings of time synchronization parameters of BDT to UTC in new type signals, and shows the leap second computational examples, helping user terminals in BDS-3 to complete their leap second adjustment. It is of an active guiding significance and great reference value for user receivers of BDS-3, and is beneficial to BDS-3 timing service promotion.
Study on the Influence of Socio-economic Activities on PM2.5 in Henan Province Based on Principal Component Regression Analysis
Authors: Yan Wei , Hou Shuangshuang , Zhou Feng , Liu Minghua , Sun Haihua
Published: April 2021

In the context of increasingly serious haze pollution in Henan Province, which is harmful to human health, it is important to clarify the impact of socio-economic activities on PM2.5, the key indicator of haze. Here, based on the analysis of the spatio-temporal variation characteristics of PM2.5 concentration in Henan Province during 2015-2018, this paper combined the data of ten socio-economic indicators and adopted the principal component regression (PCR) analysis method to explore the influence of socio-economic activities on PM2.5 concentration. The results showed that the annual average concentration of PM2.5 during 2015-2018 ranged from 59.0 μg/m3 to 83.8 μg/m3, with a decreasing rate of -5.955 μg/(m3·a). Spatial distribution of PM2.5 showed “high in the north and low in the south”, and the PM2.5 concentration in Anyang, Zhengzhou, Jiaozuo and Xinxiang were more than 75μg/m3, indicating a slightly polluted state. Among all the socio-economic indicators, gross domestic product (GDP), population density (PD), industrial value-added (IVA) and actual utilization of foreign capital (AUFC) played main positive roles in PM2.5 from 2015 to 2018 but with a diminishing trend, and afforestation area (AA) played a negative role in PM2.5. In addition, the effect of the sown area of major crops (SAMC) on PM2.5 was negative with enhanced before 2018 and reversed in 2018. Our findings can provide a basis for the government to formulate PM2.5 control policies.
Analysis of Marine environmental impact of shipping bulk liquid chemical spills
Authors: Lihong Qian , Xiaoqing Zhen , YouPing Shou , Yuxing Zhu
Published: April 2021

This paper analyzes the current transportation status and problems of bulk liquid chemicals in China, and analyzes the impact of typical chemical leakage in Yangkou port on Marine environment. The movement trajectory of Insoluble liquid bulk cargo is greatly affected by meteorological conditions and Marine hydrological conditions after they leak into the sea. The location, tidal period and amount of leakage are the main influencing factors for the difference of environmental risks of chemical leakage.
Numerical study of drill string uncertainty in acoustic information transmission
Authors: Xie Haiming , Zhang Peifen , Zhou Jing
Published: April 2021

Acoustic data transmission in drill string is one of the effective methods to solve the bottleneck of downhole information transmission speed, but its channel characteristics are mainly affected by the structural changes of string. In the process of drilling, the downhole BHA changes constantly according to the well condition, and the shape of drill string changes indefinitely under the condition of wear and force, which leads to the uncertainty of acoustic channel. Through the numerical simulation analysis, we can get the channel changes of drill string in different shapes, and analyze the main factors that affect the information transmission. The size inconsistency of multiple drill strings will lead to the deterioration of the channel characteristics to a certain extent, but the aperiodic drilling tool structure in the channel will cause a significant change in the transmission characteristics.
Characteristics of land use change Tupu in Shandong province based on multi-source data
Authors: Zhao Yuntai , Zhang Wenhui
Published: April 2021

In recent years, with the rapid pace of urbanization in China and people’s increasingly high requirements for living environment, human activities on land demand are increasing. Based on the theory and method of Geo-information Tupu, we synthesize the land use change Tupu of Shandong province during the period 2010-2018 by taking the remote sensing interpretation data as the spatial data source, so as to analyze the spatial and temporal pattern of land use change in Shandong province in recent years. The results show that: (1) the main types of land use change in Shandong province are the mutual transformation of cropland and construction land and the transformation of cropland and construction land to water area. (2) in terms of space, “ construction land→ water area” and“ cropland→ construction land” have the most concentrated distribution. The former is significantly distributed in the coastal areas of Binzhou, Dongying and Weifang. (3) the transfer of cropland into related land use change types, with larger area, smaller spatial separation and more concentrated distribution; The transfer area of woodland is small, and the spatial separation degree is large. (4) in general, the cropland area is decreasing while the construction land area is increasing.
Vegetation and vascular plant diversity of Huzhou Island, Huizhou, China
Authors: Liu Hui
Published: April 2021

Human activities have an increasingly severe impact on uninhabited islands. It is beneficial to monitor and protect the vegetation diversity of uninhabited islands to master the species composition and diversity of plant communities. The vascular plants and plant communities of Huzhou Island were investigated by sample plot method. The plant species diversity was analyzed. The results showed that there were 98 species of vascular plants belonging to 88 genera and 49 families in the island. Among them, tropical and subtropical families were dominant the island. The genera floristic distribution of vascular plants was mainly pantropic distribution and secondly old word tropic distribution.The vegetation in the island could be classified into 1 vegetation type (monsoon evergreen broad-leaved forest vegetation), 1 alliance (coastal hilly monsoon evergreen broad-leaved forest) and 2 associations (Ficus microcarpa and Eucalyptus urophylla - Myrtle). The change trend of community richness, evenness and diversity was consistent. This study can provide scientific data for resource protection and development of uninhabited island.
Three dimensional evaluation on soil improvement effect of saline alkali soil in Yellow River Delta
Authors: Han Mingzhang , Gao Mingxiu , Yang Jianhong
Published: April 2021

It is necessary to evaluate the effect of soil improvement after land consolidation for productivity improvement, but the current evaluation method is relatively single. In this paper, based on the data of soil salt content from monitoring and sampling, the statistical characteristics were analyzed by SPSS software, and the three-dimensional distribution map was constructed by using GMS10.0 software for IDW interpolation. The results showed that the soil salt content in 2019 decreased significantly by 31.29% compared with that in 2018 from the characteristics of cultivated layer, and the effect of soil improvement was obvious. From the profile characteristics, the soil salt content in the study area is characterized by “surface accumulation”. The salt content of soil profile decreased significantly at maize maturity stage compared with that before sowing. The decrease rates of soil salt content at different depths were 70.11% (0-20cm), 77.43% (20-40cm), 77.31% (40-60cm), 83.34% (60-80cm) and 65.26% (80-100cm), respectively. The decrease rate of 60-80cm soil layer was the largest. The results can be used as a reference for single index or comprehensive index three-dimensional visualization evaluation of soil improvement effect.
Recent Tectonic Stress Field in Northwest Yunnan Province
Authors: Fan Wenjie , Yao Xiuyi , Cui Xiaofeng
Published: April 2021

Based on the collected focal mechanism solutions of M≥3.0 earthquakes in Northwest Yunnan from 2000 to 2018, we used Michael’s linear inversion method to perform stress tensor inversion, and attempted to analyze the temporal and spatial evolution characteristics of the tectonic stress field in Northwest Yunnan. The results show that the types of focal mechanism solutions of earthquakes in Northwest Yunnan are complex, mainly strike-slip faulting earthquakes (46%), followed by normal faulting earthquakes (27%). The direction of maximum principal stress in the study area is NNW near NS direction, and the direction of minimum principal stress is ENE direction. It shows that the study area is subjected to horizontal compression from NNW near NS direction. According to the variation of the stress tensor variance over time, M≥5.0 earthquakes in the study area mainly occurred when the stress tensor variance was lower than 0.2. Most earthquakes occur when the variance of the stress tensor decreases, that is, when the focal mechanism solutions tend to be consistent. And these earthquakes mostly occur in the low value area of the variance and its edge.
NIR molecule induced self-assembled nanoparticles for synergistic in vivo chemo-photothermal therapy of bladder cancer
Authors: Zhu Guanchen , Zhang Qingfeng , Zhao Xiaozhi , Zhang Qing , Chen Wei , Xu Linfeng , Zhao Sheng , Wang Kaikai , Liu Tianqing , Guo Hongqian
Published: April 2021

Bladder cancer (BC) is one of the commonest malignancies in the urinary system. Bladder cancer is divided into non-muscle invasive bladder cancer (NMIBC) and muscle invasive bladder cancer (MIBC) according to the depth of invasion. Besides, the prognosis of MIBC remains poor. Surgical resection combined with radiotherapy or chemotherapy is the standard treatment for MIBC. However, the major obstacle that hinders successful chemotherapy is its lack of tumor targeting. Here, we fabricated nanoparticles that respond to near-infrared laser irradiation in order to increase the drug accumulation at the tumor sites and combine chemotherapy with photothermal therapy to overcome challenges of bladder cancer treatment. IR780 and Doxorubicin (DOX) were loaded into albumin nanoparticles (IR780-DOX@Albumin NPs). In the process of IR780-DOX@Albumin NPs synthesis, the near-infrared molecule IR780 was used as the assembly molecular bridge. Under irradiation, the nanoparticles were decomposed due to the degradation of IR780 while the release of DOX increased. Nanoparticles can be ingested by tumor cells in a short time. The IR780-DOX@Albumin NPs were sensitive to near-infrared laser irradiation. Near-infrared laser irradiation can promote the release of the drugs from the nanoparticles and induce a photothermal effect, thus destroying the tumor cells. Given the excellent tumor-targeting ability and negligible toxicity to normal tissue, IR780-DOX@Albumin NPs can greatly increase the concentration of chemotherapeutic drugs in tumor cells. This study combines photothermal therapy and chemotherapy to treat MIBC, so as to avoid chemotherapy resistance, reduce the toxicity to normal cells, and achieve the purpose of improving the treatment of MIBC.
First-principles calculations on FeWB bulk and FeWB(001)/α-Fe(111) interface
Authors: Zhuang Dengming , Liu Ying , Jin Na , Li Jun , Cao Zhinan , Zhang Jiteng
Published: April 2021

FeWB bulk and FeWB(001)/α-Fe(111) interface were studied by first-principles calculations. FeWB bulk bonding has the mixed characteristics of metallicity, covalency and ionicity, among which the metallicity is the most obvious. Such combination endows FeWB with promising toughness and excellent electrical conductivity. Adhesion work, W

ad
, was calculated for twelve different interfacial structures, taking into account four terminations of FeWB(001) and three stacking sequences. The B(Fe)-terminated center-site stacking interface is the most stable with the smallest interface distance and the largest W

ad
. Fe-B and W-B bond lengths at the interface are even shorter than those in FeWB bulk. By comparing the interface fracture work G with W

ad
, it is found that the interface fracture position has a certain occasionality, but it tends to occur in FeWB bulk. According to the results of density of states, we concluded the B(Fe)-terminated center-site stacking interface is a metallic/covalent mixing nature, while the combination of top-site stacking interface is mainly covalent bonds.
Evaluation and validation of tungsten fiducial marker-based image-guided radiotherapy
Authors: Shahid Wajeehah , Mukhtar Raheel , Rizvi Syed Faheem Askari , Shahid Samiah , Iqbal Muhammad Aamir
Published: April 2021

In this research work, a simple homemade cubic phantom was designed to validate the Image-Guided Radiotherapy (IGRT) set up and verified with the help of tungsten fiducial markers (size 2–3 mm) inserted into the cubic phantom. Phantom made up of Styrofoam, was scanned with the help of 16 slice Toshiba CT scanner where each slice was of 1 mm thickness and HU level set to −1000. A radio-opaque contrast medium was rubbed on the phantom to visualize the scanner images. Once the iso-center had been marked on a phantom with the help of in-room positioning laser and the fields (RT-LAT and AP) were applied on the contoured body of the phantom in Varian’s ARIA-11 Eclipse dosimeter software, the same position of the phantom was reproduced on Varian’s Linear Accelerator DHX. Known shifts of 3.0 to 30.0 mm from the marked iso-center were applied on the phantom by moving the couch in all six directions one by one. On each applied couch shift, an x-ray image of the phantom was acquired with the help of an MV portal imager of Linac in AP and RT-LAT direction. This image was superimposed with a reference image of phantom and shift accuracy calculated by ARIA-11 software was noted down. It turned out that irrespective of the position of the phantom on the couch, the calculated corrected shift and deviation from reference position was always between ± 1–2 mm which is the required accuracy for IGRT according to International Atomic Energy Agency (IAEA). This process was repeated 40 times and each time, the corrected shift came out to be ± 1–2 mm. We can conclude that our system is safe and accurate enough to perfectly position the actual patient for IGRT.
Highly stable and printable Ag NWs/GO/PVP composite ink for flexible electronics
Authors: Wang Shang , Feng Yan , Zhang He , Peng Qiqi , Tian Yanhong
Published: April 2021

Silver nanowire (Ag NW) ink has attracted significant attention due to its excellent conductivity for flexible electronics. However, the junctions of Ag NWs are unstable without a post-treatment process. In this paper, high-dispersibility Ag NWs/graphene oxide (GO)/polyvinyl pyrrolidone (PVP) composite ink has been synthesized. The mixing of PVP can improve the dispersibility of Ag NWs in water, and the GO is employed to enhance the connection between Ag NWs. Finally, The Ag NWs/GO/PVP composite ink-based flexible electrode (FE) reaches a resistivity of 8.6 mΩ cm after sintering at 100 °C for 15 min and shows superior reliability even after 6000 bending cycles. Moreover, the FE coated with composite ink shows a better performance than pure Ag NWs under high temperature and humidity conditions (70 °C, 75% Relative Humidity (RH)). The thermal stability of Ag NWs is also improved by GO, as the morphology nearly maintains their initial structure under 240 °C, indicating their potential applications in high-reliability flexible electronics.
Sampling Strategies for Internal Validation Samples for Exposure Measurement–Error Correction: A Study of Visceral Adipose Tissue Measures Replaced by Waist Circumference Measures
Authors: Nab Linda , van Smeden Maarten , de Mutsert Renée , Rosendaal Frits R , Groenwold Rolf H H
Published: April 2021

Statistical correction for measurement error in epidemiologic studies is possible, provided that information about the measurement error model and its parameters are available. Such information is commonly obtained from a randomly sampled internal validation sample. It is however unknown whether randomly sampling the internal validation sample is the optimal sampling strategy. We conducted a simulation study to investigate various internal validation sampling strategies in conjunction with regression calibration. Our simulation study showed that for an internal validation study sample of 40% of the main study’s sample size, stratified random and extremes sampling had a small efficiency gain over random sampling (10% and 12% decrease on average over all scenarios, respectively). The efficiency gain was more pronounced in smaller validation samples of 10% of the main study’s sample size (i.e., a 31% and 36% decrease on average over all scenarios, for stratified random and extremes sampling, respectively). To mitigate the bias due to measurement error in epidemiologic studies, small efficiency gains can be achieved for internal validation sampling strategies other than random, but only when measurement error is nondifferential. For regression calibration, the gain in efficiency is, however, at the cost of a higher percentage bias and lower coverage.
Obesity alters the ovarian proteomic response to zearalenone exposure
Authors: González-Alvarez M Estefanía , McGuire Bailey C , Keating Aileen F
Published: April 2021

Zearalenone (ZEN), a nonsteroidal estrogenic mycotoxin, is detrimental to female reproduction. Altered chemical biotransformation, depleted primordial follicles and a blunted genotoxicant response have been discovered in obese female ovaries, thus, this study investigated the hypothesis that obesity would enhance ovarian sensitivity to ZEN exposure. Seven-week-old female wild-type nonagouti KK.Cg-a/a mice (lean) and agouti lethal yellow KK.Cg-Ay/J mice (obese) received food and water ad libitum, and either saline or ZEN (40 μg/kg) per os for 15 days. Body and organ weights, and estrous cyclicity were recorded, and ovaries collected posteuthanasia for protein analysis. Body and liver weights were increased (P < 0.05) in the obese mice, but obesity did not affect (P > 0.05) heart, kidney, spleen, uterus, or ovary weight and there was no impact (P > 0.05) of ZEN exposure on body or organ weight in lean or obese mice. Obese mice had shorter proestrus (P < 0.05) and a tendency (P = 0.055) for longer metestrus/diestrus. ZEN exposure in obese mice increased estrus but shortened metestrus/diestrus length. Neither obesity nor ZEN exposure impacted (P > 0.05) circulating progesterone, or ovarian abundance of EPHX1, GSTP1, CYP2E1, ATM, BRCA1, DNMT1, HDAC1, H4K16ac, or H3K9me3. Lean mice exposed to ZEN had a minor increase in γH2AX abundance (P < 0.05). In lean and obese mice, LC–MS/MS identified alterations to proteins involved in chemical metabolism, DNA repair and reproduction. These data identify ZEN-induced adverse ovarian modes of action and suggest that obesity is additive to ZEN-induced ovotoxicity.
Bayesian integrative analysis and prediction with application to atherosclerosis cardiovascular disease
Authors: Chekouo Thierry , Safo Sandra E
Published: April 2021

The problem of associating data from multiple sources and predicting an outcome simultaneously is an important one in modern biomedical research. It has potential to identify multidimensional array of variables predictive of a clinical outcome and to enhance our understanding of the pathobiology of complex diseases. Incorporating functional knowledge in association and prediction models can reveal pathways contributing to disease risk. We propose Bayesian hierarchical integrative analysis models that associate multiple omics data, predict a clinical outcome, allow for prior functional information, and can accommodate clinical covariates. The models, motivated by available data and the need for exploring other risk factors of atherosclerotic cardiovascular disease (ASCVD), are used for integrative analysis of clinical, demographic, and genomics data to identify genetic variants, genes, and gene pathways likely contributing to 10-year ASCVD risk in healthy adults. Our findings revealed several genetic variants, genes, and gene pathways that are highly associated with ASCVD risk, with some already implicated in cardiovascular disease (CVD) risk. Extensive simulations demonstrate the merit of joint association and prediction models over two-stage methods: association followed by prediction.
Phronetically Guided Use of Knowledge: Interstitial Work at Barnahus and How It Can Inform the Knowledge Debate in Social Work
Authors: Andersen Lotte C
Published: April 2021

In this article, the ‘evidence–relevance’ dilemma in the ‘knowledge for social work’ debate is approached empirically, departing from a concrete practice observed amongst social workers managing police-reported child abuse cases within the Norwegian Barnahus model (children’s house model). This practice can be conceptualised as interstitial work and is noted as providing children who are victims of abuse with holistic and context-sensitive interventions relevant to their particular situations and needs. The relevant questions addressed are what knowledge sources are used and how is knowledge applied in practice by social workers who are able to provide their clients with relevant interventions. Based on the findings and drawing on Flyvbjerg’s approach to phronetic knowledge, it is argued that for social work practice to result in knowledge-based and relevant interventions that account for the complex nature of social problems and social work reality, the use of formal knowledge sources and evidence must be ‘phronetically guided’.
Psychological factors associated with inflammatory bowel disease
Authors: Eugenicos M P , Ferreira N B
Published: April 2021

Background

Both depression and anxiety are identified as significant experiences in inflammatory bowel disease (IBD); whether these are a consequence of the disease or an active contributor to the disease remains controversial. This review aimed to identify and critique recent evidence regarding mental health in IBD.

Sources of data

PubmedⓇ, OvidⓇ, EmbaseⓇ, EBSCO PsychInfo and Google-Scholar were searched within the last 5 years (2016–2020).

Areas of agreement

Overall, both depression and anxiety affect disease activity, relapse and healthcare utilization.

Areas of controversy

There is some controversy on whether depression and anxiety affect IBD outcomes differently depending on IBD subtype.

Growing points

The data support the need for depression and anxiety assessment to be incorporated in the routine management of IBD patients; prompt psychiatric and psychological management may ultimately reduce disease activity, relapses and healthcare costs.

Areas timely for developing research

More longitudinal research may further enlighten the role of depression and anxiety in IBD. Similarly, randomized controlled trials to investigate and clarify the effect of psychiatric/psychological management on IBD outcomes.
Plasma markers predict changes in amyloid, tau, atrophy and cognition in non-demented subjects
Authors: Pereira Joana B , Janelidze Shorena , Stomrud Erik , Palmqvist Sebastian , van Westen Danielle , Dage Jeffrey L , Mattsson-Carlgren Niklas , Hansson Oskar
Published: April 2021

It is currently unclear whether plasma biomarkers can be used as independent prognostic tools to predict changes associated with early Alzheimer’s disease.

In this study, we sought to address this question by assessing whether plasma biomarkers can predict changes in amyloid load, tau accumulation, brain atrophy and cognition in non-demented individuals. To achieve this, plasma amyloid-β 42/40 (Aβ42/40), phosphorylated-tau181, phosphorylated-tau217 and neurofilament light were determined in 159 non-demented individuals, 123 patients with Alzheimer’s disease dementia and 35 patients with a non-Alzheimer’s dementia from the Swedish BioFINDER-2 study, who underwent longitudinal amyloid (18F-flutemetamol) and tau (18F-RO948) PET, structural MRI (T1-weighted) and cognitive testing.

Our univariate linear mixed effect models showed there were several significant associations between the plasma biomarkers with imaging and cognitive measures. However, when all biomarkers were included in the same multivariate linear mixed effect models, we found that increased longitudinal amyloid-PET signals were independently predicted by low baseline plasma Aβ42/40 (P = 0.012), whereas increased tau-PET signals, brain atrophy and worse cognition were independently predicted by high plasma phosphorylated-tau217 (P < 0.004). These biomarkers performed equally well or better than the corresponding biomarkers measured in the CSF. In addition, they showed a similar performance to binary plasma biomarker values defined using the Youden index, which can be more easily implemented in the clinic. In addition, plasma Aβ42/40 and phosphorylated-tau217 did not predict longitudinal changes in patients with a non-Alzheimer’s neurodegenerative disorder.

In conclusion, our findings indicate that plasma Aβ42/40 and phosphorylated-tau217 could be useful in clinical practice, research and drug development as prognostic markers of future Alzheimer’s disease pathology.
Comorbidities of scars in China: a national study based on hospitalized cases
Authors: Kong Weishi , Xiao Yongqiang , Wang Baoli , Zhu Zhe , Hu Lunyang , Tang Hongtai , Wang Kangan , Fang He , Shi Ying , Long Jianyan , Gan Lanxia , Wang Haibo , Sun Yu , Xia Zhaofan
Published: April 2021

Background

Scar comorbidities seriously affect the physical and mental health of patients, but few studies have reported the exact epidemiological characteristics of scar comorbidities in China. This study aimed to investigate the prevalence of scar comorbidities in China.

Methods

The data of 177,586 scar cases between 2013 and 2018 were obtained from the Hospital Quality Monitoring System based on the 10th edition of the International Classification of Diseases coding system. The total distribution of scar comorbidities and their relationship with age, aetiology and body regions were analysed.

Results

Six comorbidities (contracture, malformation, ocular complications, adhesion, infection and others) were the main focus. In general, male patients outnumbered females and urban areas outnumbered rural areas. The proportion of contractures was the highest at 59,028 (33.24%). Students, workers and farmers made up the majority of the occupation. Han Chinese accounted for the majority of the ethnic. The highest proportion of scar contracture occurred at 1–1.9 years of age (58.97%), after which a significant downward trend was observed. However, starting from 50 years of age, ocular complications increased gradually and significantly, eventually reaching a peak of 34.49% in those aged >80 years. Scar contracture was the most common comorbidity according to aetiology, and the highest proportion was observed in patients who were scalded (29.33%). Contractures were also the most frequent comorbidity in hands (10.30%), lower limbs (6.97%), feet (6.80%) and upper limbs (6.02%). The mean and median hospitalization durations were 12.85 and 8 days, respectively.

Conclusions

Contractures were the most common comorbidities, and different comorbidities tended to occur at different ages and with different causative factors.
DNA Methylation and Resting Brain Function Mediate the Association between Childhood Urbanicity and Better Speed of Processing
Authors: Cheng Weiqiu , Luo Na , Zhang Yuyanan , Zhang Xiao , Tan Haoyang , Zhang Dai , Sui Jing , Yue Weihua , Yan Hao
Published: April 2021

Urbanicity has been suggested to affect cognition, but the underlying mechanism remains unknown. We examined whether epigenetic modification (DNA methylation, DNAm), and brain white matter fiber integrity (fractional anisotropy, FA) or local spontaneous brain function activity (regional homogeneity, ReHo) play roles in the association between childhood urbanicity and cognition based on 497 healthy Chinese adults. We found significant correlation between childhood urbanicity and better cognitive performance. Multiset canonical correlation analysis (mCCA) identified an intercorrelated DNAm-FA-ReHo triplet, which showed significant pairwise correlations (DNAm-FA: Bonferroni-adjusted P, Pbon = 4.99E−03, rho = 0.216; DNAm-ReHo: Pbon = 4.08E−03, rho = 0.239; ReHo-FA: Pbon = 1.68E−06, rho = 0.328). Causal mediation analysis revealed that 1) ReHo mediated 10.86% childhood urbanicity effects on the speed of processing and 2) childhood urbanicity alters ReHo through DNA methylation in the cadherin and Wnt signaling pathways (mediated effect: 48.55%). The mediation effect of increased ReHo in the superior temporal gyrus underlying urbanicity impact on a better speed of processing was further validated in an independent cohort. Our work suggests a mediation role for ReHo, particularly increased brain activity in the superior temporal gyrus, in the urbanicity-associated speed of processing.
Results from a Pre-exposure Prophylaxis Demonstration Project for At-risk Cisgender Women in the United States
Authors: Blumenthal Jill , Jain Sonia , He Feng , Amico K Rivet , Kofron Ryan , Ellorin Eric , Stockman Jamila K , Psaros Christina , Ntim Gifty M , Chow Karen , Anderson Peter L , Haubrich Richard , Corado Katya , Moore David J , Morris Sheldon , Landovitz Raphael J
Published: April 2021

Background

Daily oral tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) is effective for reducing human immunodeficiency virus (HIV) acquisition among cisgender women. We report results from the first US observational open-label demonstration project of pre-exposure prophylaxis (PrEP) among at-risk cisgender women.

Methods

Adherence Enhancement Guided by Individualized Texting and Drug Levels was a 48-week, single-arm, open-label demonstration study of daily oral TDF/FTC in cisgender women ≥18 years old at risk for HIV. Adherence was supported using 2-way text messaging and titrated adherence counseling based on rapid-turnaround tenofovir diphosphate concentrations from dried blood spots. Study visits occurred at baseline, weeks 4 and 12, and quarterly through week 48. Outcomes included TDF/FTC adherence, retention, and persistence.

Results

From June 2016 to October 2018, 136 cisgender women enrolled (mean age, 40 years (standard deviation, 11); 38% non-Hispanic Black and 19% Latina). At 48 weeks, 84 (62%) participants were retained and 62 (46%) remained on PrEP. More than one-third (12/31) of those on study but off PrEP throughout the study discontinued TDF/FTC because of side effects, and 1 adverse event led to study discontinuation. Of 120 participants with drug concentrations measured, 67 (56%) had at least 1 concentration consistent with 6 doses/week; 22 (18%) had consistent ≥6 doses/week across all study visits attended. There were no incident HIV infections and 4 incident bacterial sexually transmitted infections.

Conclusion

Adequate PrEP adherence for protective drug concentrations was not achieved for most study participants. More work needs to be done to fully explicate the reasons for nonadherence and low retention in cisgender women.
Coronavirus Disease 2019 (COVID-19) Mitigation Efforts and Testing During an In-Person Training Event—Uganda, 12–29 October 2020
Authors: Laws Rebecca L , Biraro Sam , Kirungi Wilford , Gianetti Brittany , Aibo Dorothy , Awor Anna C , West Christine , Sachathep Karampreet K , Kiyingi Herbert , Ward Jennifer , Mwangi Christina , Nkurunziza Peter , Okimait David , Currie Dustin , Ajiboye Aderonke , Moore Carole S , Patel Hetal , Sendagala Sam , Naluguza Mary , Mugisha Veronicah , Low Andrea , Delgado Stephen , Hoos David , Brown Kristin , Galbraith Jennifer S , Hladik Wolfgang , Nelson Lisa , El-Sadr Wafaa , Musinguzi Joshua , Voetsch Andrew C
Published: April 2021

Large public-health training events may result in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) transmission. Universal SARS-CoV-2 testing during trainings for the Uganda Population-based HIV Impact Assessment identified 28 of 475 (5.9%) individuals with coronavirus disease 2019 (COVID-19) among attendees; most (89.3%) were asymptomatic. Until COVID-19 vaccine is readily available for staff and participants, effective COVID-19 mitigation measures, along with SARS-CoV-2 testing, are recommended for in-person trainings, particularly when trainees will have subsequent contact with survey participants.