bluuebunny/crossref_metadata_2025_split huggingface dataset:
Integrated laser based pre‐tempering at laser welding of AISI 1045 steel by using 3D‐scanner optics
Authors: Steidle F. , Hofele M. , Ketzer‐Raichle G. , Gooßen M. , Riegel H. 
Published: November 2021

AbstractLaser‐based pre‐heating of laser beam welding with a 3D scanning optics, applied to AISI 1045 steel, is studied. Laser beam welding of heat‐treatable steel is challenging due to martensitic hardening in combination with defects. Pre‐tempering aims the reduction of the cooling rates and martensitic microstructure within the weld seam. An oscillating defocused laser beam was guided over the surface for pre‐heating by means of a 3D scanner optics. During pre‐heating, the laser power, the scanning speed and the number of cycles were varied. Welding with 4000 W and 2 m/min with a focused laser beam was executed. Thus the resulting temperature profile behind the ongoing laser beam and cooling time T8|5 between 800 °C–500 °C was significantly extended. Two parameter combinations (15 cycles|600 W|50 mm/s(2) and 10 cycles|800 W|50 mm/s2) succeeded in a microstructure of bainite and martensite. By extending the cooling time T8|5 to 3.11 s(2) and 4.17 s2. Thus, average hardness for laser based pre‐tempering of 487 HV 0.5(2) and 455 HV 0.52 was achieved. As a reference, global pre‐heating at 400 °C using a heating plate can reduce the average hardness of the weld zone from 729 HV 0.5 at room temperature to 304 HV 0.5 at a cooling time T8|5 of 5.63 s.
Microstructure, mechanical and erosion wear analysis of post heat treated iron alloy based coating with varying chromium
Authors: Sharma R. K. , Das R. K. , Kumar S. R. 
Published: November 2021

AbstractThe present work focuses on the effect of annealing heat treatment on the microstructure, mechanical and erosion properties of iron alloy based coatings with varying chromium content. High velocity oxygen fuel coating method was used to deposit the coating over the substrate material 316 L stainless steel. The study was done in terms of microstructural analysis using x‐ray diffractometer, surface and cross‐sectional morphology using field emission scanning electron microscope, mechanical and erosion wear analysis. It was found that x‐ray diffractometer indicated presence of less amount of titanium dioxide (TiO2) and silicon dioxide (SiO2) after heat treatment. However, the peaks of hardened phase of diironylidenetitanium (Fe2Ti) and iron‐chromium (Fe−Cr) was increased. Addition of chromium up to 10 wt. % improved the hardness and adhesion pull of strength by 16 % and 62 % respectively. On the other side heat treatment of iron alloy based coating having 10 wt. % chromium increased the hardness and adhesion pull off strength by 17.3 % and 35 % respectively. The erosion wear rate was also decreased with the annealing process. The study shows that the annealing process increases hardness and adhesion pull off strength but decreases porosity and erosion wear rate.
Analysis of tribological behaviour of aluminum‐titanium carbide‐basalt metal matrix composite
Authors: Muthu P. 
Published: November 2021

AbstractIn the recent years, particulate reinforced aluminum based matrix composites are playing an important role in automobile and aerospace applications due to their enhanced properties. In this work, an attempt has been made to optimize the tribological behaviour of aluminum 7075 matrix reinforced with titanium carbide (3 percent weight) and basalt particles (2 percent weight) using Taguchi based grey relational analysis. Composites are fabricated according to american society for testing materials standard using stir casting method dry sliding wear tests were carried out using pin on disc apparatus as per Taguchi's L9 orthogonal array. Grey relational analysis was used to obtain the optimum process parameters for multiple quality characteristics such as wear rate and coefficient of friction. Then significant contribution of wear parameters was determined by analysis of variance. A confirmatory test was carried out to validate the test result. Finally, the micro structural investigation on the worn surfaces was performed by scanning electron microscope.
Spontaneous Graft‐Induced Dyskinesias Are Independent of 5‐HT Neurons and Levodopa Priming in a Model of Parkinson's Disease
Authors: Lane Emma L. , Harrison David J. , Ramos‐Varas Elena , Hills Rachel , Turner Sophie , Lelos Mariah J. 
Published: November 2021

ABSTRACTBackgroundThe risk of graft‐induced dyskinesias (GIDs) presents a major challenge in progressing cell transplantation as a therapy for Parkinson's disease. Current theories implicate the presence of grafted serotonin neurons, hotspots of dopamine release, neuroinflammation and established levodopa‐induced dyskinesia.ObjectiveTo elucidate the mechanisms of GIDs.MethodsNeonatally desensitized, dopamine denervated rats received intrastriatal grafts of human embryonic stem cells (hESCs) differentiated into either ventral midbrain dopaminergic progenitor (vmDA) (n = 15) or ventral forebrain cells (n = 14).ResultsOf the eight rats with surviving grafts, two vmDA rats developed chronic spontaneous GIDs, which were observed at 30 weeks post‐transplantation. GIDs were inhibited by D2‐like receptor antagonists and not affected by 5‐HT1A/1B/5‐HT6 agonists/antagonists. Grafts in GID rats showed more microglial activation and lacked serotonin neurons.ConclusionsThese findings argue against current thinking that rats do not develop spontaneous GID and that serotonin neurons are causative, rather indicating that GID can be induced in rats by hESC‐derived dopamine grafts and, critically, can occur independently of both previous levodopa exposure and grafted serotonin neurons. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
Versatility of the lateral circumflex femoral artery sparing perforator‐based anterolateral thigh flaps in loco‐regional thigh reconstruction after skin cancer, melanoma, and sarcoma resection
Authors: Brunetti Beniamino , Salzillo Rosa , Tenna Stefania , Morelli Coppola Marco , Persichetti Paolo 
Published: November 2021

AbstractBackgroundThe anterolateral thigh (ALT) flap represents a workhorse in reconstructive microsurgery but its use in a free style fashion as perforator‐based flap has yet to be popularized. We describe our experience with lateral circumflex femoral artery (LCFA) sparing perforator‐based ALT flaps for thigh reconstruction after oncological resection in a case series of 24 consecutive patients.MethodsTwenty‐four patients underwent thigh reconstruction with 25 perforator‐based ALT flaps between 2014 and 2020. Defect etiology was related to skin cancer, melanoma, and sarcoma resection in 3, 7, and 14 cases respectively. Mean defect size was 15 × 8 cm. Six months postoperatively, patients were asked to rate on a 5‐point Likert scale the aesthetic and functional outcomes of the reconstructive procedure.ResultsEight flaps were advanced in a V‐Y fashion (33.3%), whether 16 flaps (66.7%) were rotated in a propeller fashion. The average flap size was 19 × 8 cm, while mean operative time was 197.2 min. Donor sites were always closed by primary intention. Minor complications were registered in 5 cases and managed conservatively. Overall patients' satisfaction was high, with mean aesthetic and functional ratings of 4.46 and 4.21 respectively.ConclusionsLCFA sparing perforator‐based ALT flaps proved to be a versatile and reproducible solution to address thigh reconstruction after oncological resection according to the different topographical sub‐units involved.
First assessment of thermoacoustic tomography for in vivo detection of rheumatoid arthritis in the finger joints
Authors: Chi Zihui , Huang Lin , Wu Dan , Long Xiaojun , Xu Xueliang , Jiang Huabei 
Published: November 2021

AbstractBackgroundThe diagnosis of rheumatoid arthritis (RA) is complicated because of the complexity of symptoms and joint structures. Current clinical imaging techniques for the diagnosis of RA have strengths and weaknesses. Emerging imaging techniques need to be developed for the diagnosis or auxiliary diagnosis of RA.PurposeThis study aimed to demonstrate the potential of thermoacoustic tomography (TAT) for in vivo detection of RA in the finger joints.MethodsFinger joints were imaged by a TAT system using three different microwave illumination methods including pyramidal horn antenna, and parallel in‐phase and anti‐phase microwave illuminations. Both diseased and healthy joints were imaged and compared when the three microwave illumination methods were used. Magnetic resonance imaging (MRI) of all the joints was performed to validate the TAT findings. In addition, two diseased joints were imaged at two time points by the pyramidal horn antenna‐based TAT to track/monitor the progression of RA during a time period of 16 months. Three‐dimensional (3‐D) TAT images of the joints were also obtained.ResultsThe TAT images of the diseased joints displayed abnormalities in bone and soft tissues compared to the healthy ones. The TAT images by pyramidal horn antenna and in‐phase microwave illumination showed high similarity in image appearance, while the anti‐phase‐based TAT images provided different information about the disease. We found that the TAT findings matched well with the MRI images. The 3‐D TAT images effectively displayed the stereoscopic effect of joint lesions. Finally, it was evident that TAT could detect the development of the lesions in 16 months.ConclusionTAT can noninvasively visualize bone lesions and soft tissue abnormalities in the joints with RA. This first in vivo assessment of TAT provides a foundation for its clinical application to the diagnosis and monitoring of RA in the finger joints.
Comprehensive comparison of local effect model IV predictions with the particle irradiation data ensemble
Authors: Pfuhl Tabea , Friedrich Thomas , Scholz Michael 
Published: November 2021

AbstractPurposeThe increased relative biological effectiveness (RBE) of ions is one of the key benefits of ion radiotherapy compared to conventional radiotherapy with photons. To account for the increased RBE of ions during the process of ion radiotherapy treatment planning, a robust model for RBE predictions is indispensable. Currently, at several ion therapy centers the local effect model I (LEM I) is applied to predict the RBE, which varies with biological and physical impacting factors. After the introduction of LEM I, several model improvements were implemented, leading to the current version, LEM IV, which is systematically tested in this study.MethodsAs a comprehensive RBE model should give consistent results for a large variety of ion species and energies, the particle irradiation data ensemble (PIDE) is used to systematically validate the LEM IV. The database covers over 1100 photon and ion survival experiments in form of their linear‐quadratic parameters for a wide range of ion types and energies. This makes the database an optimal tool to challenge the systematic dependencies of the RBE model. After appropriate filtering of the database, 571 experiments were identified and used as test data.ResultsThe study confirms that the LEM IV reflects the RBE systematics observed in measurements well. It is able to reproduce the dependence of RBE on the linear energy transfer (LET) as well as on the αγ/βγ ratio for several ion species in a wide energy range. Additionally, the systematic quantitative analysis revealed precision capabilities and limits of the model. At lower LET values, the LEM IV tends to underestimate the RBE with an increasing underestimation with increasing atomic number of the ion. At higher LET values, the LEM IV overestimates the RBE for protons or helium ions, whereas the predictions for heavier ions match experimental data well.ConclusionsThe LEM IV is able to predict general RBE characteristics for several ion species in a broad energy range. The accuracy of the predictions is reasonable considering the small number of input parameters needed by the model. The detailed quantification of possible systematic deviations, however, enables to identify not only strengths but also limitations of the model. The gained knowledge can be used to develop model adjustments to further improve the model accuracy, which is on the way.
Optimal control problems for a semi‐linear integro‐differential evolution system with infinite delay
Authors: Huang Hai , Fu Xianlong 
Published: November 2021

AbstractWe study in this work the optimal control and time optimal control problems for a semi‐linear integro‐differential evolution system with infinite delay in Hilbert space. We first study the existence and uniqueness result of mild solutions in space for the considered system, and the main tools here are the theory of resolvent operators and fractional powers of operators and norm. In this way the obtained results are more general and can be applied to the systems involving terms having spatial derivatives. Then we discuss the Lagrange optimal control problem for the system via limit arguments. The time optimal control problem is also proposed and investigated deliberately for it. Finally, an example is provided to show the applications of the obtained results.
Regression and pseudoprogression of pediatric optic pathway glioma in patients treated with proton beam therapy
Authors: Youn Sang Hee , Kim Haksoo , Lee Sang Hyeon , Kim Joo‐Young 
Published: November 2021

AbstractPurposeWe examined regression patterns in pediatric optic pathway gliomas (OPGs) after proton beam therapy (PBT) and evaluated local control and visual outcomes.MethodsA total of 42 brain magnetic resonance imaging (MRI) scans from seven consecutive sporadic OPGs that were initially treated with chemotherapy and received PBT between June 2007 and September 2016 at the National Cancer Center, Korea were analyzed. Patients underwent brain MRI regularly before and after PBT. Total tumor, cystic lesion, and solid enhancing lesion area delineation and volume calculations were performed on gadolinium‐enhanced T1‐weighted MRI using Eclipse version 13, Varian.ResultsThe median follow‐up period after PBT was 70 months (range 47–88). The median age at the time of PBT was 7 years (range 4–16) and the median duration of chemotherapy before referral to PBT center was 25 months (range 3–70). The median time to the greatest increase in cystic volume was 32 months (range 12–43) after PBT. Solid enhancing lesion volume gradually decreased throughout the follow‐up period. On an individual basis, total volume change was varied. However, on average, it regressed, although at a slower rate than solid enhancing lesion volume did. The local control rate was 85.7% (5‐year progression‐free survival rate, 80%; 5‐year overall survival rate, 100%) and the rate of vision preservation was 71.4% (five of seven patients).ConclusionThe regression patterns in pediatric OPGs after PBT involve significant cystic change. Therefore, total volume is not appropriate for evaluating response. Care by a multidisciplinary team is necessary to manage clinical symptoms related to radiologic changes.
Compositional analysis of essential oil and solvent extracts of Norway spruce sprouts by ultrahigh‐resolution mass spectrometry
Authors: Mofikoya Omolara O. , Mäkinen Marko , Jänis Janne 
Published: November 2021

AbstractIntroductionConiferous trees, especially their needles and bark, are a rich source of bioactive compounds. The developing needles of Norway spruce (Picea abies), also known as spruce sprouts, are enriched with vitamin C and other antioxidants, and thus they are used as a dietary supplement and have been traditionally used to treat various inflammatory disorders such as rheumatism and gout. Their chemical composition is only limitedly known, however.ObjectivesThe main objective of this work was to have a deeper understanding on the chemical composition of spruce sprouts to assess their full potential in different pharmaceutical, nutraceutical, or technochemical applications.Materials and methodsUltrahigh‐resolution Fourier‐transform ion cyclotron (FT‐ICR) mass spectrometry, coupled to direct‐infusion electrospray ionisation (ESI) or atmospheric pressure photoionisation (APPI) techniques, was used for in‐depth compositional analysis of solvent extracts and essential oil of spruce sprouts.ResultsA combined use of ESI and APPI techniques offered a great complementary insight into the rich chemistry of different spruce sprout extracts, allowing detection of thousands of chemical constituents with over 200 secondary metabolites tentatively identified. These compounds belonged to different classes such as organic acids, terpenes, flavonoids, stilbenes, sterols, and nitrogen alkaloids.ConclusionSpruce sprouts have a complex metabolite profile that differs considerably from that of the old, developed needles.
Polypropylene‐based in situ fibrillation‐reinforced ternary composite foams with improved filler‐phase dispersion
Authors: Wu Gaojian , Song Renda , Ma Yitao , Xie Jinzhao , Yang Weimin , Xie Pengcheng 
Published: November 2021

AbstractRecently, the issue of energy‐saving and environmental protection has attracted enormous interest in developing polymeric composite foams. Fillers have been identified as major materials to tailor cellular structures and mechanical properties for single component thermoplastics. However, it is often difficult to achieve the desired effect due to the natural tendency of fillers. The study aims to provide a facile method for improving the dispersion and arrangement of filler phase based on in situ fibrillation. Polytetrafluoroethylene (PTFE) was used in the in situ fibrillated phase to promote the dispersion of talc throughout the polypropylene (PP) matrix for the ternary composite foams of PP/talc/PTFE. The mechanisms of PTFE fibrils and their effect were studied in terms of crystallization, rheology, foaming behavior, and mechanical properties. The results proved that a fibrillar network was formed by the PTFE fibrils with high aspect ratios, which had a remarkable effect on melt strength and viscoelasticity, thus improving the cellular structure and impact strength. Moreover, the higher the talc content, the better the effect on these properties with the existence of PTFE fibrils, indicating that the in situ fibrillated phase improved fillers dispersion and enhanced the reinforcing effect of filler phase.
An adaptive CUSUM chart for drift detection
Authors: Yi Fan , Qiu Peihua 
Published: November 2021

AbstractIn practice, sequential processes often have gradual changes in their process distributions over time. This is related to the drift detection problem in statistical process control. In the literature, there have been some existing discussions on this problem. But, most existing methods are designed based on the assumption that the related drift is linear or have another specific pattern. In reality, however, such specified patterns may not be valid. In this paper, we suggest an adaptive cumulative sum (CUSUM) chart to handle the drift detection problem with a flexible drift pattern. The new method integrates the general framework to construct a CUSUM chart based on the generalized likelihood ratio statistic and estimation of a shift size by the exponentially weighted least square regression procedure. Simulation studies show that the proposed method is effective in various cases considered. The new method is also illustrated using an example about the exchange rates between Indian Rupees and US Dollars.
‘We'd never had to set up a virtual school before’: Opportunities and challenges for primary and secondary teachers during emergency remote education
Authors: Gouseti Anastasia 
Published: November 2021

AbstractThe Covid‐19 pandemic has brought about the largest disruption to formal education in recent history and has resulted in school closures and the move to online teaching and learning across the globe. Using data from interviews with 25 teachers and head teachers in England and Greece, this paper aims to capture educators’ experiences during emergency remote education (ERE) in spring–summer 2020 and contribute to current and future conversations about the post‐pandemic school. Through a qualitative approach, the paper reports on the often improvised and compromised nature of online schooling during the first pandemic lockdown and presents the opportunities and challenges teachers experienced with the move to emergency remote education. It discusses how didactic modes of teaching prevailed, highlights the importance of parental involvement during ERE and argues that the move to online teaching and learning has accentuated digital inequalities. The findings of this study cast light on the hitherto unexplored area of ERE and offer original insights for future policy making, research and practice on how schools can develop readiness and resilience to face future closures in a post‐pandemic world.
Impulsive control for attitude stabilization in the presence of unknown bounded external disturbances
Authors: Jiang Bangxin , Lu Jianquan , Li Xiaodi , Shi Kaibo 
Published: November 2021

AbstractIn this article, impulsive control is firstly considered for the quaternion‐based attitude stabilization of a rigid spacecraft. Inspired by the robustness of sliding mode control, a new concept of impulsive‐sliding mode is proposed to design robust impulsive controller for attitude stabilization. It illustrates that the designed impulsive controller possesses simple structure and robustness with respect to external disturbances. In order to achieve the relaxation of continuous measurement, we utilize periodic state measurement that is more economical and practical than the continuous one. Namely, we can achieve attitude stabilization and resource economization by adopting only discrete state measurement and discrete control input. More interestingly, our results can overcome the difficulty that the upper bound of disturbances is unknown, which is often required to design adaptive controller to handle in previous results. Moreover, we prove that thephenomenon can be excluded under the proposed periodic event‐triggering strategy and the interevent time has a uniform lower bound. An illustrative example is presented to show the feasibility of our results.
Wide Dynamic Range Thermometer Based on Luminescent Optical Cavities in Ga2O3:Cr Nanowires
Authors: Alonso‐Orts Manuel , Carrasco Daniel , San Juan José M. , Nó María Luisa , de Andrés Alicia , Nogales Emilio , Méndez Bianchi 
Published: November 2021

AbstractRemote temperature sensing at the micro‐ and nanoscale is key in fields such as photonics, electronics, energy, or biomedicine, with optical properties being one of the most used transducing mechanisms for such sensors. Ga2O3 presents very high chemical and thermal stability, as well as high radiation resistance, becoming of great interest to be used under extreme conditions, for example, electrical and/or optical high‐power devices and harsh environments. In this work, a luminescent and interferometric thermometer is proposed based on Fabry–Perot (FP) optical microcavities built on Cr‐doped Ga2O3 nanowires. It combines the optical features of the Cr3+‐related luminescence, greatly sensitive to temperature, and spatial confinement of light, which results in strong FP resonances within the Cr3+ broad band. While the chromium‐related R lines energy shifts are adequate for low‐temperature sensing, FP resonances extend the sensing range to high temperatures with excellent sensitivity. This thermometry system achieves micron‐range spatial resolution, temperature precision of around 1 K, and a wide operational range, demonstrating to work at least in the 150–550 K temperature range. Besides, the temperature‐dependent anisotropic refractive index and thermo‐optic coefficient of this oxide have been further characterized by comparison to experimental, analytical, and finite‐difference time‐domain simulation results.