bluuebunny/crossref_metadata_2025 huggingface dataset:
Simethicone and N-acetyl cysteine combination as premedication before esophagogastroduodenoscopy: Double-blind randomized controlled trial
Authors: Krishnamurthy Veeraraghavan , Joseph Abel , Venkataraman Shreyas , Kurian George
Published: May 2022

Background and study aims Esophagogastroduodenoscopy (EGD), the most common method used for diagnosing upper gastrointestinal diseases, is often limited by the presence of foam and mucous. Thus, this study was designed to detect whether the combination of simethicone with N-acetyl cysteine (NAC) as premedication before EGD improves mucosal visualization.

Patients and methods A total of 768 consenting patients were enrolled in this prospective, double-blind, randomized placebo-controlled trial in four groups (A: simethicone + N-acetyl cysteine; B: simethicone alone; C: NAC alone; and D: placebo). After 20 minutes of consuming the corresponding solution, EGD was done and multiple images were obtained from the esophagus, stomach, and duodenum. Based on the various images obtained, the study parameters were calculated. Statistical Analysis Software (SAS) was used to analyze the results using Kruskal-Wallis with the Bonferroni correction method.

Results The study population consisted of 57 % men and the mean age was 44.18 years. Each group was randomized with 192 participants. Group A (combination of simethicone + NAC) premedication had the lowest total mucosal visibility score of 8.31, a significantly lower score for mucous/bubbles obscuring the vision, and less time to complete the procedure. Also, 81 % of the participants in group A did not require flushing to clear the mucous/bubbles. There were no side effects due to this premedication in any of the groups.

Conclusions  Using simethicone and NAC combined for premedication may improve the quality of EGD.
Evaluation of an all-in-one hybrid model (EUS Magic Box) for stepwise teaching and training in multiple interventional EUS procedures
Authors: Dhir Vinay , Udawat Priyanka , Shah Rahul , Alahari Aruna
Published: May 2022

Background and study aims While multiple interventional endoscopic ultrasound (EUS)-guided procedures have evolved over the past two decades, there is no model that allows for training in all of these procedures. We aimed to develop and validate an all-in-one hybrid model for stepwise learning in multiple EUS interventions.

Methods A hybrid model was created utilizing a pig esophagus and stomach, a silicon-based duodenum and pancreato-biliary system, a pseudocyst, and biopsy targets. This model was designed to provide hands-on training in multiple interventional EUS procedures, such as EUS-guided fine-needle biopsy (EUS-FNB), biliary drainage (BD), pancreatic duct drainage (PD), pseudocyst drainage (PSD), and gastro-enterostomy (GE). Thirty-six trainees underwent training on this model over 6 days, in two batches. Lumen apposing metal stents were used for PSD and GE. Trainees were assessed for objective criteria of technical difficulties. Subjective assessment by trainees was done via a questionnaire.

Results All the trainees were able to complete the requisite steps for all the procedures under supervision. On subjective assessment, 30 trainees (83 %) graded the model as good or excellent. A total of 107 technical difficulties were noted (scope position 55, duct puncture 27, guidewire-related problems 25). Time taken to complete the requisite steps of biopsy, PSD, and GE (10.5 minutes; range 3.5 to 22) was significantly less than that for BD and PD (28 minutes; range 17 to 40) (P < 0.001).

Conclusions The hybrid model provided training for multiple EUS interventions with good acceptance by trainees. Stepwise mentoring with the possibility of performing multiple procedures in a single model with or without X-ray could prove useful in conference as well as institutional settings.
Factors contributing to changes in viscosity and flow rate of a dedicated gel for gel immersion endoscopy
Authors: Hiraki Yuji , Ohata Atsushi , Yano Tomonori , Miura Yoshimasa , Lefor Alan Kawarai , Yamamoto Hironori
Published: May 2022

Background and study aims Gel immersion endoscopy is a novel technique for securing the visual field during endoscopy. Clinical application of a dedicated gel for this technique with an appropriate viscosity to prevent mixing with blood and its efficacy was reported. The aim of this study was to evaluate changes in gel viscosity and flow rate under different conditions.

Methods The viscosity of the gel after injection and flow rate were measured under various conditions changing the injection route and method. Gel viscosity was measured at 25, 10, and 4 °C.

Results A decrease in gel viscosity was found when the gel was injected via the water jet channel compared to the accessory channel. The flow rate and decrease in viscosity of the gel injected via the water jet channel were 220 mL/min and 63.2 %, while when injected via the accessory channel with a clip device inserted were 560 mL/min and 35.8 %. When the gel was kept at a low temperature, the viscosity increased.

Conclusions Gel injection via the accessory channel should be the first choice for efficient use considering the viscosity and flow rate.
Leading-to-trailing edge theoretical design of a generic scramjet
Authors: Carneiro R. , Araújo P. P. B. , Marinho G. S. , Martos J. F. A. , Passaro A. , Toro P. G. P.
Published: May 2022

The aerospace vehicle flying at hypersonic speed, using an airbreathing propulsion system based on supersonic combustion (scramjet) technology, requires a highly integrated system without moving parts, making the propulsion system and vehicle shape indistinguishable. A scramjet uses shock waves, generated by its inlet during the hypersonic flight to provide the temperature and velocity of atmospheric air to burn the hydrogen, at the combustor at supersonic speed. The divergent exhaust nozzle accelerates the combustion products providing the thrust. A two-dimensional hydrogen-powered generic scramjet has been designed to demonstrate supersonic combustion in atmospheric flight at a Mach number of 6.8 and an altitude of 30 km. Temperature and velocity at the combustion chamber are the most important key parameters for a preliminary design. The inlet configuration must provide a temperature higher than the ignition temperature of the fuel to guarantee spontaneous combustion and the velocity must remain supersonics. The nozzle exit velocity should be higher than the vehicle flight velocity to obtain sustained flight and produce enough thrust. For this theoretical analysis, the air is considered a calorically perfect gas without viscous effects. The compressible flow is analyzed based on oblique shock waves and one-dimensional compressible flow with friction and heat addition and Prandtl–Meyer coupled to the area ratio to describe each key component of the scramjet, such as compression, combustor, and nozzle sections, respectively. The inlet mass flow and hydrogen mass flow are also critical for the scramjet design to ensure stoichiometrically combustion at the combustion chamber, generating the high flow velocity at the nozzle to produce thrust.
Potential soluble substrates for transient electronics applications: A review
Authors: Mohanty Sheetikanta , Arya Avi , Jena Dipun , Guhathakurata Shrabani , Manik Nabin Baran , Ahmad Gufran , Mallik Sandipan
Published: May 2022

The excessive usage and demand of consumer electronics have caused an elevation of electronic waste. Typically, consumer electronics are produced with non-biodegradable, non-biostable, and sometimes fatal materials, resulting in global alarming biological summons. Thence, to mend the drawbacks, an emerging field—named transient electronics—takes effect where the biomaterial, device, substrate, and total systems disappear untraceably after steady-state operation. Conspicuously, transient electronics have induced immense curiosity in researchers to perform interesting investigations due to the feature of disintegration after stable operation. The idea of transient electronics has been implemented in biomedical, military, and nanotechnology fields. Although rapid development is evident in transient technology in a short period, it is believed that the technology will deliver the utmost prospects in advanced electronic applications. Essentially, in transient technology, the vital challenge is to determine the platform materials that offer stability, resistance, biocompatibility, and mainly, the solubility to accommodate the transient devices. In this Review, a detailed overview of different soluble substrates, such as organic, polymer, and solid-state substrates, is described, along with the feasibility of the fabricated devices on the respective substrates to support transient electronics. Second, the dissolving mechanism of the corresponding substrates is analyzed.
Stability and contrast in bimodal amplitude modulation atomic force microscopy for different mode combinations in ambient air
Authors: Zhou Xilong , Zhuo Rongshu
Published: May 2022

Bimodal amplitude modulation atomic force microscopy (AM-AFM) is widely used in nanoscale topography and mechanical property imaging for a variety of materials. In this paper, the stability of the amplitude/phase spectroscopy curves and the imaging contrast in bimodal AM-AFM for different mode combinations are investigated computationally in ambient air. The results show that with the second mode amplitude used for topography feedback on a stiff material, the amplitude/phase spectroscopy would probably undergo volatile fluctuation, leading to unstable imaging. With the third mode amplitude set for topography imaging, it would be difficult for the feedback to maintain the prescribed amplitude since a large cantilever position variation is required for different sample moduli. With the first mode amplitude set for topography feedback, the amplitude and the phase of the second mode vary monotonically with sample modulus or viscosity in comparison with the third or the fourth mode, which is suitable for compositional contrast imaging. These results would provide useful guidelines for optimum imaging in bimodal AFM measurements.
Tuning the resonance frequency of piezoelectric energy harvesters by applying direct current electric field on piezoelectric elements
Authors: Duan Guan , Li Yingwei , Tan Chi
Published: May 2022

Different from previous strategies utilized to improve the energy conservation efficiency of piezoelectric energy harvesters (PEHs) from the environment, by broadening the frequency-bandwidth of energy harvesters using a specifically designed structure or tuning their resonance frequency (RF) through changing the geometrical/dynamical constraints, we report a method—by applying a direct current (DC) electric field on piezoelectric elements—to tune the RF of PEH based on the phenomenon that the elastic parameters of piezoelectric material are related to its electric field boundary condition. The results of a confirmatory experiment revealed that with a pre-loading DC electric field of −0.5 to 0.75 kV/mm, the RF of a piezoelectric cantilever energy harvester can be tuned from 144 to 156 Hz. The effectiveness of this strategy was further verified by comparing the energy conservation output of the PEH at a frequency that deviates from its RF, and at the same frequency, with pre-loading DC electric field adjustment.
Slow optical response of semi-insulating GaN film studied by terahertz emission and photoluminescence spectroscopy
Authors: Murakami Fumikazu , Mannan Abdul , Serita Kazunori , Murakami Hironaru , Tonouchi Masayoshi
Published: May 2022

We report the terahertz emission spectroscopy (TES) and photoluminescence (PL) spectroscopy results for a semi-insulating (SI) GaN film in comparison with those for unintentionally doped (UID) and magnesium (Mg)-doped ones. The TES and PL results showed notable slow changes on a time scale of approximately 10 s for the SI and UID GaN films, but not for the Mg-doped GaN film upon femtosecond ultraviolet laser illumination. The origin of the slow responses of the TES and PL spectra was studied by observing them under ambient air and vacuum conditions and attributed to hydrogen dissociation from GaN as a result of optical excitation.
Dynamic community detection over evolving networks based on the optimized deep graph infomax
Authors: Liu Hao , He Langzhou , Zhang Fan , Wang Zhen , Gao Chao
Published: May 2022

As complex systems, dynamic networks have obvious nonlinear features. Detecting communities in dynamic networks is of great importance for understanding the functions of networks and mining evolving relationships. Recently, some network embedding-based methods stand out by embedding the global network structure and properties into a low-dimensional representation for community detection. However, such kinds of methods can only be utilized at each single time step independently. As a consequence, the information of all time steps requires to be stored, which increases the computational cost. Besides this, the neighbors of target nodes are considered equally when aggregating nodes in networks, which omits the local structural feature of networks and influences the accuracy of node representation. To overcome such shortcomings, this paper proposes a novel optimized dynamic deep graph infomax (ODDGI) method for dynamic community detection. Since the recurrent neural network (RNN) can capture the dynamism of networks while avoiding storing all information of dynamic networks, our ODDGI utilizes RNN to update deep graph infomax parameters, and thus, there is no need to store the knowledge of nodes in full time span anymore. Moreover, the importance of nodes is considered using similarity aggregation strategy to improve the accuracy of node representation. The experimental results on both the real-world and synthetic networks prove that our method surpasses other state-of-the-art dynamic community detection algorithms in clustering accuracy and stability.
An estimation method of the spatial resolution for magnifying fast neutron radiography
Authors: Li J. J. , Dong Y. S. , Yu B. , Chen Z. J. , Zheng J. H. , Yao L. , Yang J. M.
Published: May 2022

Fast neutron radiography (FNR) using divergent neutron beams has the characteristic to magnify small cracks in low-Z materials. For such magnifying FNR systems, a simple method was developed using Monte Carlo simulations to estimate the spatial resolution. The resolution degrading factors, including neutron source size, object thickness, and crosstalk in the detector, have been investigated in this method. The calculated results of this method compare favorably to independent estimations of various designs for the same FNR system. For a magnifying FNR system, a better spatial resolution can be expected with larger magnifications and smaller sources.
High-pressure polycrystalline thin-film synthesis and semiconducting property of platinum pernitride
Authors: Niwa Ken , Iizuka Tomoki , Kurosawa Masashi , Nakamura Yuto , Okadome Valencia Hubert , Kishida Hideo , Nakatsuka Osamu , Sasaki Takuya , Gaida Nico Alexander , Hasegawa Masashi
Published: May 2022

A polycrystalline platinum pernitride (PtN2) thin-film was successfully synthesized via nitridation of a platinum thin-film deposited on α-Al2O3 substrate at the pressure of ∼50 GPa by using the laser-heated diamond anvil cell. The current–voltage characteristic and optical reflectance of the synthesized PtN2 thin-film were measured under ambient conditions. Combined with first-principles calculations, these experimental results have revealed that PtN2 exhibits semiconducting property with a bandgap of ∼2 eV. This high-pressure thin-film synthesis technique could also be applied for revealing the physical properties of other novel pernitrides synthesized under ultra-high pressure, which can offer new insights into the physical properties and functionality of the pernitrides and related nitrides.
Enhanced hole injection and transport property of thermally deposited copper thiocyanate (CuSCN) for organic light-emitting diodes
Authors: Hwang Hui Ung , Yoon Jiyoung , Lee Youn-Seoung , Lee Jangwon , Lee Jonghee , Lim Kyung-Geun , Kim Jeong Won
Published: May 2022

Due to its high conductivity, broad bandgap, and low manufacturing cost, copper thiocyanate (CuSCN) thin film has been considered a good hole injection layer (HIL)/transport layer in many opto/electronic devices. However, the CuSCN thin films made by the conventional wet process have limitations in terms of interfacial deterioration due to solvent incorporation and charge trap formation due to impurities. We produce a CuSCN film for HIL in organic light-emitting diode (OLED) devices using vacuum deposition and compare it to a solution-processed film. In comparison to the control device, the CuSCN HIL insertion lowers the driving voltage of fabricated OLEDs by 1.0–1.5 V. The low-voltage operation corresponds to better hole transport in hole-only devices. The vacuum-deposited CuSCN, in particular, has an impurity-free composition and a high density of band-tail states, according to chemical and electronic structural studies. Because of their outstanding quality, vacuum-deposited CuSCN films show clear advantages over solution-based films in device performance and manufacture.
Distortion modes and ferroelectric properties in hybrid improper ferroelectric Sr3(Sn,Zr)2O7 ceramics
Authors: Chen Q. S. , Zhang B. H. , Chen B. H. , Liu X. Q. , Chen X. M.
Published: May 2022

In the present work, the distortion modes and ferroelectric properties of Sr3(Sn1−xZrx)2O7 (x = 0.0, 0.25, 0.5, 0.75, 1.0) ceramics with double-layered Ruddlesden–Popper structures were investigated. The amplitudes of three distortion modes for the ferroelectric phase deviated from the aristotype one were quantified using the symmetry-mode approach adopted in Rietveld refinement against x-ray diffraction patterns. The remanent polarization and the coercive field decreased with increasing the content of Zr4+ cations. The decline of polarization should attribute to the nonpolar secondary phase, while the suppression of a coercive field may connect with the decreased amplitude of the rotation mode. The Curie temperatures increased linearly with increasing x value in Sr3(Sn1−xZrx)2O7 ceramics, inducing from the decline of a tolerance factor. A typical first-order improper ferroelectric phase transition was determined using a differential scanning calorimetry measurement and dielectric characterization. From the present work, a straightforward way to quantify the amplitude of a distortion mode for the ferroelectric phase was given, and the ferroelectric properties could be effectively tuned by substituting the cations at the B site in the Sr-based hybrid improper ferroelectrics.
Development of the text of the Ramsar Convention: 1965–1971
Authors: Stroud David A. , Davidson Nick C. , Finlayson C. Max , Gardner Royal C.
Published: May 2022

The ‘Ramsar’ Convention on Wetlands was the first of the modern era global biodiversity conventions and remains the only multilateral environmental agreement focused on a single group of ecosystem types. At the time of initial discussions within the wetland conservation science community in the late 1960s, its ambition was unprecedented, with no successful models to draw upon, especially with regard to novel concepts such as the modus for an ‘internationally protected site’. Drawing on previously unpublished draft texts, we track the Convention’s textual development to its ultimate agreement in 1971. During this period its geographic scope changed from an initial European to global focus, whereas core obligations related to the designation of internationally important wetlands and the provision of secretariat coordination functions were substantively developed. We present (as supplementary material) all draft texts, from 1965 to 1971, previously unavailable online.
Do bird communities differ with post-fire age in
Authors: Davis Robert A. , Valentine Leonie E. , Craig Michael D.
Published: May 2022

Prescribed fire is a widespread management practice in fire-prone ecosystems that can have significant effects on fauna. To inform the development of appropriate prescribed burning regimes, we explored bird responses to time since fire in threatened Banksia woodlands in south-western Australia. We used area searches to estimate bird densities on 20 plots ranging from 1 to 26 years post fire. Fire had no significant effect on the overall bird community or any foraging guilds and there was no clear post-fire succession. Of the 26 frequently occurring species analysed, only two showed responses to fire, with yellow-rumped thornbills more abundant in early and late post-fire sites and scarlet robins more abundant in either early, or early and late post-fire habitats. Our study suggested that bird communities in Banksia woodlands are quite adaptable to a range of prescribed burning regimes. However, owing to late-successional reptiles, Carnaby’s black cockatoo and mammals in Banksia woodlands, we recommend prescribed burning regimes that reduce early and increase late successional habitat. Phytophthora dieback, urbanisation and associated habitat fragmentation and a drying climate may have important synergistic effects and the role of these in structuring bird communities needs to be further considered in developing appropriate fire regimes.
Hinge point emergence in mammalian spinal neurulation
Authors: de Goederen Veerle , Vetter Roman , McDole Katie , Iber Dagmar
Published: May 2022

Significance

Spinal neural tube folding shows a transition from medial to dorsolateral neural plate bending sites (hinge points) along the embryo’s body axis. While hinge points are considered an important driving force in neural tube closure, their biomechanical origin is poorly understood. Here we use a computational model based on mouse and human embryo imaging data to show that the median hinge point emerges in simulations combining mesoderm expansion, nonneural ectoderm expansion, and neural plate adhesion to the notochord. Furthermore, dorsolateral hinge points emerge through a medial pulling force exerted by dorsal nonneural ectoderm (zippering). This indicates that spinal neural tube folding could be primarily driven by mesoderm expansion and zippering, with hinge points passively emerging in response to extrinsic forces.
Interplay between quantum anomalous Hall effect and magnetic skyrmions
Authors: Li Yang , Xu Shengnan , Wang Jianfeng , Wang Chong , Yang Baishun , Lin Haiqing , Duan Wenhui , Huang Bing
Published: May 2022

Significance

Quantum anomalous Hall effect (QAHE) and magnetic skyrmion (SK), as two typical topological states in momentum (
K
) and real (
R
) spaces, attract much interest in condensed matter physics. However, the interplay between these two states remains to be explored. We propose that the interplay between QAHE and SK may generate an
RK
joint topological skyrmion (
RK
-SK), characterized by the SK surrounded by nontrivial chiral boundary states (CBSs). Furthermore, the emerging external field–tunable CBS in
RK
-SK could create additional degrees of freedom for SK manipulations, beyond the traditional SK. Meanwhile, external field can realize a rare topological phase transition between
K
and
R
spaces. Our work opens avenues for exploring unconventional quantum states and topological phase transitions in different spaces.
Crescent-shaped shadow of second harmonic generation in dielectric microsphere/TMD monolayer heterostructure
Authors: Xia Chuansheng , Cui Qiannan , Ding Haibo , Chen Jinping , Wang Ru , Zhang Lu , Yang Ying , Wang Xiaoxuan , Xu Wenxiong , Shi Zengliang , Li Yuanyuan , Zhu Gangyi , Xu Chunxiang
Published: May 2022

For heterointerfaces at micro/nano scales, extremely-space-confined second harmonic generation (SHG) of transition metal dichalcogenide (TMD) monolayers can facilitate the extraction of TMD monolayers’ 3D dielectric environment. Here, we construct SiO2 microsphere/MoS2 monolayer (3D/2D) heterostructures and spatially resolve their SHG distributions via pixel-to-pixel spatial mapping. Asymmetric 3D refractive index distribution of the microsphere is successfully projected to 2D plane of TMD monolayer and visualized by corresponding 2D image of SHG intensity distribution, which presents a crescent-shaped shadow. Out results open up new possibilities for 3D interfacial sensing and imaging with SHG of 2D monolayers.
Study of oxygen plasma treatment on solution-processed SnO
x
thin-film transistors
Authors: Ren Yajie , Zhang Danna , Ding Yanan , Liu Guoxia , Shan Fukai
Published: May 2022

In this study, the effect of oxygen plasma treatment (OPT) on the electrical performance of the SnO
x
thin film transistors (TFTs) were investigated. The SnO
x
thin films were fabricated by solution process and integrated into the TFTs as channels. According to the x-ray photoelectric spectroscopy analysis, the oxygen vacancies in the SnO
x
thin films are significantly reduced after OPT. The electrical performances of the SnO
x
TFTs treated with various plasma power and treatment time were systematically studied. Compared with untreated SnO
x
TFT, the one with OPT of 40 W for 90 s exhibits optimum electrical performance, including the variation of the current on/off ratio (I
on/I
off) from ∼103 to 107 and threshold voltage (V
TH) from −10.78 to 3.97 V. Meanwhile, the operation mode of the SnO
x
TFTs is changed from depletion mode to enhancement mode. When the SnO
x
TFT is integrated with high-k Al2O3 dielectric, the TFT exhibits better electrical performance, including the V
TH of 0.14 V, an I
on/I
off of 107, a field-effect mobility (µ
FE) of 5.57 cm2 V−1 s−1, and a subthreshold swing of 570 mV dec−1. These results prove that the OPT process for SnO
x
TFTs is a facile and efficient method in the flat panel display industries.
The 2022 solar fuels roadmap
Authors: Segev Gideon , Kibsgaard Jakob , Hahn Christopher , Xu Zhichuan J , Cheng Wen-Hui (Sophia) , Deutsch Todd G , Xiang Chengxiang , Zhang Jenny Z , Hammarström Leif , Nocera Daniel G , Weber Adam Z , Agbo Peter , Hisatomi Takashi , Osterloh Frank E , Domen Kazunari , Abdi Fatwa F , Haussener Sophia , Miller Daniel J , Ardo Shane , McIntyre Paul C , Hannappel Thomas , Hu Shu , Atwater Harry , Gregoire John M , Ertem Mehmed Z , Sharp Ian D , Choi Kyoung-Shin , Lee Jae Sung , Ishitani Osamu , Ager Joel W , Prabhakar Rajiv Ramanujam , Bell Alexis T , Boettcher Shannon W , Vincent Kylie , Takanabe Kazuhiro , Artero Vincent , Napier Ryan , Cuenya Beatriz Roldan , Koper Marc T M , Van De Krol Roel , Houle Frances
Published: May 2022

Renewable fuel generation is essential for a low carbon footprint economy. Thus, over the last five decades, a significant effort has been dedicated towards increasing the performance of solar fuels generating devices. Specifically, the solar to hydrogen efficiency of photoelectrochemical cells has progressed steadily towards its fundamental limit, and the faradaic efficiency towards valuable products in CO2 reduction systems has increased dramatically. However, there are still numerous scientific and engineering challenges that must be overcame in order to turn solar fuels into a viable technology. At the electrode and device level, the conversion efficiency, stability and products selectivity must be increased significantly. Meanwhile, these performance metrics must be maintained when scaling up devices and systems while maintaining an acceptable cost and carbon footprint. This roadmap surveys different aspects of this endeavor: system benchmarking, device scaling, various approaches for photoelectrodes design, materials discovery, and catalysis. Each of the sections in the roadmap focuses on a single topic, discussing the state of the art, the key challenges and advancements required to meet them. The roadmap can be used as a guide for researchers and funding agencies highlighting the most pressing needs of the field.
Large-area large-grain CsPbCl3 perovskite films by confined re-growth for violet photodetectors
Authors: Guo Tong , Zhao Shiqi , Chu Zihao , Ma Jingli , Xu Wanjin , Li Yanping , Shi Zhifeng , Ran Guangzhao
Published: May 2022

CsPbCl3 perovskite is an attractive semiconductor material with characteristics such as a wide bandgap, high chemical stability, and excellent optoelectronic properties, which broaden its application prospects for ultraviolet (UV) and violet photodetectors (PDs). However, large-area CsPbCl3 films with high coverage, large grains, and controllable thickness are still difficult to prepare by using the solution method due to the extremely low solubility of their precursors in conventional solvents. Herein, a water-assisted confined re-growth method is developed, and a CsPbCl3 microcrystalline film with an area of 3 cm × 3 cm is grown, the thickness of which is controllable within a range of several microns. The as-prepared thin film exhibits a flat and smooth surface, large grains, and enhanced photoluminescence. Furthermore, the fabricated violet PDs based on the prepared CsPbCl3 film show a high responsivity of 2.17 A W−1, external quantum efficiency of 664%, on/off ratio of 2.58 × 103, and good stability. This study provides a prospective solution for the growth of large-area, large-grain, and surface-smooth CsPbCl3 films for high-performance UV and violet PDs.
Reflections on beam configuration optimization for intensity-modulated proton therapy
Authors: Cao Wenhua , Rocha Humberto , Mohan Radhe , Lim Gino , Goudarzi Hadis M , Ferreira Brígida C , Dias Joana M
Published: May 2022

Presumably, intensity-modulated proton radiotherapy (IMPT) is the most powerful form of proton radiotherapy. In the current state of the art, IMPT beam configurations (i.e. the number of beams and their directions) are, in general, chosen subjectively based on prior experience and practicality. Beam configuration optimization (BCO) for IMPT could, in theory, significantly enhance IMPT’s therapeutic potential. However, BCO is complex and highly computer resource-intensive. Some algorithms for BCO have been developed for intensity-modulated photon therapy (IMRT). They are rarely used clinically mainly because the large number of beams typically employed in IMRT renders BCO essentially unnecessary. Moreover, in the newer form of IMRT, volumetric modulated arc therapy, there are no individual static beams. BCO is of greater importance for IMPT because it typically employs a very small number of beams (2-4) and, when the number of beams is small, BCO is critical for improving plan quality. However, the unique properties and requirements of protons, particularly in IMPT, make BCO challenging. Protons are more sensitive than photons to anatomic changes, exhibit variable relative biological effectiveness along their paths, and, as recently discovered, may spare the immune system. Such factors must be considered in IMPT BCO, though doing so would make BCO more resource intensive and make it more challenging to extend BCO algorithms developed for IMRT to IMPT. A limited amount of research in IMPT BCO has been conducted; however, considerable additional work is needed for its further development to make it truly effective and computationally practical. This article aims to provide a review of existing BCO algorithms, most of which were developed for IMRT, and addresses important requirements specific to BCO for IMPT optimization that necessitate the modification of existing approaches or the development of new effective and efficient ones.
Ohmic contact morphology improvement with reduced resistance using Si/Au/Ti/Al/Ni/Au (AlGaN) and Si/Au/Ti/Al/Ni/Au (InAlN) stack layers in III-Nitride HEMTs
Authors: Visvkarma Ajay Kumar , Laishram Robert , Kapoor Sonalee , Rawal D S , Vinayak Seema , Saxena Manoj
Published: May 2022

This article reports a Ti/Al-based ohmic contact utilizing a thin interfacial Au layer for improved morphology, edge acuity and low contact resistance for applications to III-Nitride high electron mobility transistors (HEMTs). Conventional Ti/Al contacts are based on a metal stack of the form Ti/Al/X/Au, where X is any suitable barrier layer such as Ni. The formation of ohmic contact in GaN and its alloy systems is governed by the formation of TiN during annealing; Au inter-diffusion during annealing also assists the formation of TiN islands and aids in reducing the contact resistance. Furthermore, inter-metallic phase formation between Ti and Al lowers the contact resistance. It is observed that the contact surface morphology strongly depends on the top Au layer thickness. Insertion of a very thin Au layer (2–3 nm) has drastically improved the surface quality with the achievement of contact resistance as low as 0.36 Ω mm and a specific contact resistance of 2.4 × 10−6 Ω cm2 on AlGaN/GaN HEMT. The reduction in contact resistance is due to the formation of more conducting intermetallic phases during annealing, which is assisted due to the thin Au layer insertion. Further reduction in the contact resistance to 0.13 Ω mm was also achieved with the introduction of Si as a dopant layer in the reported metal scheme. The measured rms surface roughness was reduced to ∼8 nm from 0.12 µm in comparison to the conventional ohmic contact.
Topological phase transitions and Weyl semimetal phases in chiral photonic metamaterials
Authors: Han Ning , Liu Jianlong , Gao Yang , Zhou Keya , Liu Shutian
Published: May 2022

Recently, topologically nontrivial phases in chiral metamaterials have been proposed. However, a comprehensive description of topological phase diagrams and transitions in chiral metamaterials has not been presented. In this work, we demonstrate several forms of topological phase transitions and study the existence of edge states in different phases. In the local/lossless chiral media system, the topological phase transitions are associated with Weyl points. Along with the transitions, the edge state and Fermi arc exhibit a series of changes. When the nonlocal effect is introduced, the system shows phase transition between type-I/II Weyl semimetal phase and trivial phase. Moreover, the dissipative system also undergoes topological phase transitions owing to the annihilation of the topological charges. Our work could be helpful for the application of topological concepts and rich the topological wave physics in metamaterials.
Energy loss correction on multiple Coulomb scattering of muons simulated by Geant4
Authors: Zhang Chao , Cao Xingzhong , Li Chong , Zhai Jiajia , Kuang Peng , Jin Shuoxue , Wang Baoyi , Wei Long
Published: May 2022

The scattering angle distribution of muons passing through an object is crucial reference data for the application of the accelerator muon scattering imaging. In this study, the scattering angle distribution of muons in the accelerator energy region was simulated using the Monte Carlo toolkit Geant4 and calculated using the Molière’s theory. The results show that a significant deviation occurs when Molière’s theory is used to calculate the scattering angle distribution of muons in the accelerator energy region. We demonstrated that the deviation is due to the energy loss. Therefore, an energy loss correction was introduced on Molière’s theory, after which the calculated results are in good agreement with the Geant4 simulation. Furthermore, the relative error caused by using Moliere’s theory with different energy losses was calculated for muons of different energies, which can help clarify the importance of energy loss for accelerator muon scattering imaging.
Structural, electronic and optical DFT investigation of ruthenium doped anatase TiO2 for photocatalytic applications
Authors: Hedhili Fekhra , Gandouzi Mohamed , Al-Shomar Shereen M , Mahmood Q , Chebaane Saleh , Alimi Fathi , Meftah Abdelaziz
Published: May 2022

Structural, electronic and optical properties of Ru doped anatase TiO2 have been carried out by density functional theory (DFT) calculation method in order to investigate the effect of ruthenium doping fraction and explore new properties of the material. The doped TiO2 exhibits good tetragonal structural stability. Beside the pure TiO2, we have studied the properties of the compositions RuTi15O32 and RuTi7O16. We have noticed that TiO2 semiconductor with a calculated band gap of 3.09 eV, when doped to RuTi15O32, exhibits a remarkable decrease of the bandgap width resulting from spin-up and spin-down states. Moreover, when increasing the Ru fraction no bandgap has been observed. In fact, the RuTi7O16 material has shown a metallic behavior. In addition, the dielectric function and the absorption coefficient have been discussed for the different doped systems.

The results obtained herein suggest that the incorporation of ruthenium in TiO2 crystal structure may form new materials with novel properties suitable for possible use in prospective technologies such as photocatalytic applications, as well as in spintronic and optoelectronic devices.
Design, production, burn-in and tests of the hybrid circuits of the Upstream Tracker at the LHCb detector
Authors: Citterio M. , Conti N. , De Benedetti F. , Gandini P. , Merli A. , Neri N. , Petruzzo M. , Spadaro Norella E.
Published: May 2022

We present a description of the design process, prototyping and production of the hybrid circuits for the front-end electronics of the Upstream Tracker at LHCb. The multilayer polyamide-based printed circuit boards, or hybrids, are designed to host the front-end ASICs. The ASICs require an optimized power delivery network from 0 to 120 MHz, with a maximum of 10−2 Ohms round-trip resistance, and 100 Ohms differential traces. Hybrids are required to have minimal radiation length, and to withstand the harsh environmental conditions of the data taking through intrinsic radiation hardness characteristics.
The central role of forests in the 2021 European floods
Authors: Insua-Costa Damián , Senande-Rivera Martín , Llasat María Carmen , Miguez-Macho Gonzalo
Published: May 2022

Plants play a key role in the hydrological cycle, yet their contribution to extreme rainfall remains uncertain. Here we show that more than half of the vast amounts of water accumulated in the recent Germany and Belgium floods were supplied by vegetation (41% from transpiration, 11% from interception loss). We found that intercontinental transport of moisture from North American forests (which contributed more than 463 billion liters of water to the event) was a more important source than evaporation over nearby seas, such as the Mediterranean or the North Sea. Our results demonstrate that summer rainfall extremes in Europe may be strongly dependent on plant behavior and suggest that significant alterations in vegetation cover, even of remote regions, could have a direct effect on these potentially catastrophic events.
Soil moisture thresholds explain a shift from light-limited to water-limited sap velocity in the Central Amazon during the 2015–16 El Niño drought
Authors: Meng Lin , Chambers Jeffrey , Koven Charles , Pastorello Gilberto , Gimenez Bruno , Jardine Kolby , Tang Yao , McDowell Nate , Negron-Juarez Robinson , Longo Marcos , Araujo Alessandro , Tomasella Javier , Fontes Clarissa , Mohan Midhun , Higuchi Niro
Published: May 2022

Transpiration is often considered to be light- but not water-limited in humid tropical rainforests due to abundant soil water, even during the dry seasons. The record-breaking 2015–16 El Niño drought provided a unique opportunity to examine whether transpiration is constrained by water under severe lack of rainfall. We measured sap velocity, soil water content, and meteorological variables in an old-growth upland forest in the Central Amazon throughout the 2015–16 drought. We found a rapid decline in sap velocity (−38 ± 21%, mean ± SD.) and in its temporal variability (−88%) during the drought compared to the wet season. Such changes were accompanied by a marked decline in soil moisture and an increase in temperature and vapor pressure deficit. Sap velocity was largely limited by net radiation during the wet and normal dry seasons; however, it shifted to be primarily limited by soil moisture during the drought. The threshold in which sap velocity became dominated by soil moisture was at 0.33 m3 m−3 (around −150 kPa in soil matric potential), below which sap velocity dropped steeply. Our study provides evidence for a soil water threshold on transpiration in a moist tropical forest, suggesting a shift from light limitation to water limitation under future climate characterized by increased temperature and an increased frequency, intensity, duration and extent of extreme drought events.
Sustainable intensification in the Brazilian cattle industry: the role for reduced slaughter age
Authors: Skidmore Marin Elisabeth , Sims Kaitlyn M , Rausch Lisa L , Gibbs Holly K
Published: May 2022

The cattle industry in the Brazilian Amazon causes vast deforestation while producing at only one-third of the sustainable capacity. Slaughtering cattle at a younger age directly increases production per hectare per year, all else equal, and provides a potential path for sustainable intensification. Here we show that slaughter age is decreasing in the Amazon biome, but this increase in productivity varies across space and throughout the cattle supply chain. We characterize the properties and municipalities that have reduced slaughter age, providing insights into the incentives and barriers to this form of intensification. Most notably, reductions in slaughter age occurred in regions with low remaining forest cover and on properties with little current deforestation, suggesting that ranchers intensify via slaughter age as an alternative to deforestation. We then estimate how changing production practices to reduce slaughter age can reduce enteric methane emissions, accounting for production of additional feed. Our results indicate that reducing slaughter age through improved pasture and feed sources are a path to lower global GHG emissions from cattle production, particularly as beef is increasingly produced in developing countries with historically higher emissions. Yet in the Amazon, deforestation remains the leading source of GHG emissions, necessitating that any effort to reduce slaughter age must be coupled with strict enforcement of zero-deforestation policy. Our findings demonstrate the potential of policy limiting deforestation as a means to reduce both emissions from deforestation and enteric emissions from cattle.
On the Robin spectrum for the equilateral triangle*
Authors: Rudnick Zeév , Wigman Igor
Published: May 2022

The equilateral triangle is one of the few planar domains where the Dirichlet and Neumann eigenvalue problems were explicitly determined, by Lamé in 1833, despite not admitting separation of variables. In this paper, we study the Robin spectrum of the equilateral triangle, which was determined by McCartin in 2004 in terms of a system of transcendental coupled secular equations. We give uniform upper bounds for the Robin–Neumann gaps, showing that they are bounded by their limiting mean value, which is hence an almost sure bound. The spectrum admits a systematic double multiplicity, and after removing it we study the gaps in the resulting desymmetrized spectrum. We show a spectral gap property, that there are arbitrarily large gaps, and also arbitrarily small ones, moreover that the nearest neighbour spacing distribution of the desymmetrized spectrum is a delta function at the origin. We show that for sufficiently small Robin parameter, the desymmetrized spectrum is simple.
Enhanced near-infrared reflectance and functional characteristics of nano metal oxide embedded alkyd coatings
Authors: Benitha V S , Jeyasubramanian K , Prabhin V S
Published: May 2022

The main idea of the research is to formulate alkyd based smart coatings with high NIR-reflectance to decrease the cooling load in order to maintain cool comfort in buildings. In addition to the NIR reflectance studies, the physical characteristics of the coating such as glossiness, hiding power, spreading area, volatile organic contents are evaluated. Heat reflective coatings are prepared by ball milling technique utilizing white metal oxide nanoparticles (NPs) titanium oxide (TiO2), zinc oxide (ZnO) and zirconium oxide (ZrO2) as pigments. The x-ray Diffraction (XRD) and Field Emission Scanning Electron Microscopy (FESEM) results reveal the prepared metal oxide pigments are of high purity. Bonding interaction between the alkyd resin and the NPs are studied using Fourier transform infrared spectroscopy (FTIR).The spectral reflectance of the prepared coatings are measured using spectrophotometer in the solar spectrum range, wherein ZnO based nanocoatings shows better results. The cool comfort is measured for ZnO nanocoatings in an enclosed glass cabinet and the differences in temperature with respect to exposure to sunlight are highlighted. Finally, a prototype coated with ZnO NPs maintains lower indoor temperature than the commercially available white paint coated model in the order of 2.7 °C.
An extendable Space-Time Curvature Mode model
Authors: Kornreich Philipp G
Published: May 2022

Einstein calculated the curvature of space-time from a Field equation based on an equation of motion derived by the variation of a geodetic path and a second rank Metric tensor. In this study a Space-Time Curvature Mode (STCM) model is calculated from a series of coupled Field equations derived from the variation of a Taylor series expansion of a Lagrangian potential of the STCM. The Taylor series expansion coefficients are Metric tensors of increasing rank. The STCM model can be extended to any number of Field equations. The coupled Field equations of the STCM describe the warping of space-time by masses and energy fields, and the effect of the curved space-time on the motion of masses and energy fields. This results in a description of space coordinates that have locally positive and negative slopes as a function of the time coordinate and can describe a Universe with at times an accelerating expansion and at later times a contracting Universe. This study replaces the postulated concepts of Einstein’s Cosmological constant and postulated concepts of Dark Mass and Dark Energy. It is shown that the Hamiltonian is conserved.
Ultrasound emergency lateral-to-medial parasternal pericardiocentesis with high frequency probe in COVID-19: a case report
Authors: Ferro Baldassare , Vegnuti Lara , Santonocito Orazio , Roncucci Paolo
Published: May 2022

Background

The pathological involvement of the heart is frequent in SARS-Coronavirus-2 infection (COVID-19) with various clinical and echocardiographic manifestations during the course of the disease.

Case summary

A 69-year-old female patient with severe COVID-19-related acute respiratory distress syndrome undergoing mechanical ventilation developed acute left ventricular dysfunction, that successfully improved with vasoactive therapy. After 5 days, she suddenly developed hemodynamic instability due to acute onset of pericardial effusion, which required emergency pericardiocentesis. Ultrasound-guided parasternal pericardiocentesis with high-frequency linear probe and lateral-to-medial in-plane approach was performed by inserting a central venous catheter using a Seldinger technique. 700 mL of serous fluid was drained resolving the acute critical state.

Discussion

Pericardial effusion with cardiac tamponade is a rare manifestation of Covid-19. Despite the diffusion of echocardiography, emergency cardiac procedures could be particularly difficult to be performed in a pandemic scenario of limited resources and the heterogeneous skills of the professional figures involved in the management of COVID-19 patients. The spread of expertise in ultrasound-guided vascular cannulation makes this approach attractive for anesthesiologists, emergency medicine and critical care specialists too. Furthermore in this pericardiocentesis’ technique, the high-frequency linear probe adds optimal spatial resolution to maintain a close control of the needle’s direction. However the need of a good parasternal view and a deep ultrasound knowledge are crucial to avoid iatrogenic complications. In conclusion, ultrasound-guided lateral-to-medial parasternal pericardiocentesis with high-frequency linear probe is an alternative to treat potential lethal acute haemodynamic instability due to cardiac tamponade.