bluuebunny/crossref_metadata_2025 huggingface dataset:
Twinnability of Ti-V Binary Alloys: Simulation and Experiment
Authors: Xing H. , Dong A.P. , Huang J.
Published: October 2020

Recently metastable β titanium alloys has attracted much attention due to their important application in biomaterials. In this study, the defects and mechanical properties of bcc disordered β Ti-alloys are investigated theoretically by first-principles method. The elastic moduli, generalized stacking fault energies, twinnability in β Ti-V alloys were surveyed by calculations with virtual crystal approximation. The results show that the structural stability and generalized stacking fault energy decrease with reducing valence electron number (e/a) in the β Titanium alloys. Both twinning formation energies and twinning migration energies decrease with reducing electron valance numbers, which suggests that the energy barrier for twinning formation deceases with lower structural stability. The twins in the metastable Ti-25 at.%V alloy can form near the crack tip or triggered by the high local stress during the nucleation. As the twin is thickened, the required local stress is also greatly reduced and it can grow away from the crack tip for metastable titanium alloys. Transmission electron microscopy (TEM) shows that twins are more easily observed in Ti-V alloys with relatively low electron concentrations, which confirms the theoretical conclusion that the lower the electron concentration, the easier the twin formation.
Exploration of Nano-scale Structural Instabilities in Metastable β Titanium Alloys Using Advanced Electron Microscopy
Authors: Zheng Yufeng , Wang Dong , Banerjee Rajarshi , Banerjee Dipankar , Wang Yunzhi , Fraser Hamish L.
Published: October 2020

A variety of nano-scale structural instabilities formed in different metastable β titanium alloys have been systematically investigated using advanced characterization techniques. The characteristics of three different types of nano-scale structural instabilities, the transformation mechanisms and pathways involved and the critical experimental conditions to generate such nano-scale phases will be reviewed and summarized, including athermal ω phase with hexagonal structure, O’ phase with orthorhombic structure, and incommensurate modulated nanodomains. The athermal ω phase has been observed in the as-quenched state in Ti-xMo (x=12, 15 and 181), Ti-18Mo-5Al, Ti-20V, Ti-5Fe, Ti-5Al-5Mo-5V-3Cr (Ti-5553) and Ti-24Nb-4Zr-8Sn (Ti-2448). O’ phase has been characterized to co-exist with athermal ω phase in the as-quenched state isomorphous titanium alloys, including Ti-26Zr-2Al (at.%), Ti-18Mo, Ti-18Mo-5Al, Ti-5553 and Ti-2448. Incommensurate modulated nanodomains were found in compositionally graded Ti-xFe alloy when the athermal ω phase is suppressed. These various nano-scale structural instabilities need to be taken into consideration when designing novel metastable β titanium alloys to optimize the mechanical performance by microstructure engineering.
Phase transformation during continuous heating in a β-quenched Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe alloy
Authors: Wu Cong , Zhao Yongqing , Sun Qiaoyan , Zhou Lian
Published: October 2020

As a new near β titanium alloy designed by NIN (the Northwest Institute for Non-ferrous Metal Research), the phase transformations of the β-quenched Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe alloy during continuous heating have been investigated by means of in situ dilatometer test coupled with X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The β-quenched Ti-5321 alloy with an initial structure consisting of metastable β phase and dense ωath, which was subjected to continuous heating treatment and underwent the following transformations: β + ωath→ β + ωiso→ β + α+ ωiso→ β + α. The ωisophase precipitated at 300 ℃ with a ~3 nm ellipsoidal morphology. When continuously heated to 390 ℃, a coexistence of both ωiso and α phase was observed in the β matrix, the platelet-like α phase closely nucleating at the ω/β interface with ~1 nm in width and ~8 nm in length. The α phase subsequently developed into lamellar structure when heated to higher temperatures, with a width of ~20 nm at 570 ℃ and ~85 nm at 690 ℃ respectively. Meanwhile, these α laths were uniformly distributed and composed of two distinct orientations within the microstructure. Finally, it can be found that the α morphology is directly associated with the formation and decomposition of the metastable ωisophase which may lead to the homogeneous and fine distribution of α precipitates. Based on the study of phase transformations occurring during the continuous heating process presented in this paper, an efficient guidance to engineer the microstructures and mechanical properties of this new near β titanium alloy was offered.
Microstructure formation during thermomechanical processing in Ti-17 alloy
Authors: Chandiran Elango , Miyamoto Goro , Furuhara Tadashi
Published: October 2020

The microstructure evolution during solution treatment at (alpha+beta) two phase region and subsequent aging process at 620 ˚C, after compressing the specimen in beta structure to different strain (0-70%) followed by cooling to room temperature has been investigated. Deformation strain hardly affects the total volume fraction of alpha phase after the solution treatment and aging process. On the other hand, with an increase in deformation strain, the volume fraction of the primary alpha phase increased although secondary alpha phase decreased, during the aging process, scuhdecrease in secondary alpha phase volume fraction results in a decrease in the strength. The loss of coherency of alpha/beta interphase boundaries at higher deformation strain promoted by dynamic recovery increases the interfacial mobility; which results in faster growth of primary alpha, thereby decreases secondary alpha precipitation.
Ti-15Mo alloy prepared by cryogenic milling and spark plasma sintering
Authors: Terynková A. , Kozlík J. , Bartha K. , Chráska T. , Stráský J.
Published: October 2020

In this study, Ti-15Mo alloy powder was prepared by gas atomization and subsequent cryogenic milling in order to achieve ultra-fine grained microstructure. Both milled and non-milled powders were compacted by spark plasma sintering (SPS) at temperature of 800 °C for different sintering times up to 6 minutes. Sintering temperature and time affect porosity, microstructure and phase composition of the alloy. Milled powder can be sintered at comparatively lower temperature to achieve fully dense material. Sintering below β-transus temperature results in α+β-structure. Furthermore, amount of α-phase is higher in the material sintered from the milled powder due to increased oxygen content and also due to refined microstructure which facilitates α-phase precipitation. Mechanical properties are also affected by formation of ω-phase during uncontrolled cooling in the SPS machine.
Phase transformation sequence of Ti-6Al-4V as a function of the cooling rate
Authors: Ricardo BUZOLIN , Desirée WEISS , Alfred KRUMPHALS , Michael LASNIK , Maria Cecilia POLETTI
Published: October 2020

The growth kinetics of allotriomorphic α along the prior β grain boundaries and of globular primary α in Ti-6Al-4V during continuous cooling is described. A physical model is developed based on classical nucleation and growth of platelets for the allotriomorphic α. The growth of the primary α is modelled based on the growth of spherical particle immerged on a supersaturated β-matrix. Continuous cooling tests at two different holding temperatures in the α+β field, 930°C and 960°C, and five different cooling rates, 10, 30, 40, 100 and 300°C/min, are conducted to validate the proposed models and elucidate the growth sequence of those α morphologies. Additionally, interrupted tests at different temperatures are conducted to determine the progress of growth of primary α and formation allotriomorphic α during cooling. The size of primary α increases while its size distribution broadens with a decrease in cooling rate. Area fractions of primary α decrease with increasing cooling rate and increasing holding temperature. Moreover, the lower the cooling rate, the thicker the plates of allotriomorphic α. At the beginning of the cooling, growth of primary α, as well as formation of allotriomorphic α plates is observed. The experimental and modelled results show good agreement.
Effect of mechanical surface treatments on the high temperature oxidation of pure titanium: the role of nitrogen
Authors: Lavisse L. , Kanjer A. , Berger P. , Peyre P. , Gorny C. , François M. , Optasanu V. , Montesin T. , de Lucas M. C. Marco
Published: October 2020

The mechanically treated high temperature (700°C) oxidation of commercially pure titanium was studied for long exposures (3000 h). The treatments studied here are the shot-peening and the laser-shock peening. The mass gain was measured by discontinued weighing. SEM and Raman imaging revealed strong differences between laser-shock peened, shot-peened and untreated oxidized samples. The laser treatment leads to thin compact and protective oxide layer while the shot-peened and untreated samples exhibit cracked oxide layers. The distribution of light elements like carbon, oxygen and nitrogen was revealed by Ion Beam Analysis. The presence of nitrogen located at the interface between the oxide scale and the metal was revealed on laser-shock peened samples. It is supposed the nitrogen slows-down the oxygen diffusion into the metal. The extent of the oxygen-enriched metal is also smaller on LSP samples, which improves the ductility of titanium.
Phase transformation and evolution of dislocation structure in the β phase of Ti-17 alloy during hot deformation
Authors: Yamanaka K. , Mori M. , Matsumoto H. , Chiba A.
Published: October 2020

The hot deformation behavior and microstructural evolution of Ti–5Al–2Sn–2Zr–4Mo–4Cr (Ti-17) alloy in the β-phase field were examined. Hot compression tests were conducted at temperatures ranging from 700 and 1100 °C and strain rates ranging from 10-3 to 1 s-1. The obtained true stress–true strain curves exhibited steady-state flow behavior at temperatures above the β-transus temperature (Tβ ~ 890 °C). The microstructural observations suggested that the dynamic recovery process represents a dominant mechanism for the β-phase of the alloy. In contrast, the flow softening was identified at 700 °C at a strain rate of 10–3 s–1. The formation of fine acicular α microstructures was noticed in such a deformation condition, indicating that dynamic phase transformation can occur in the metastable β-phase during hot deformation. Such a dynamic phase transformation also occurred preferentially at the initial β-grain boundaries as well as sub-boundaries that created within the βmatrix via dynamic recovery. The β-processing conditions were also examined by constructing processing maps based on the dynamic materials model (DMM).
Corona und die Pflege
Authors: Eikelmann Matthias
Published: October 2020

Vor einigen Wochen standen viele Bürgerinnen und Bürger auf ihren Balkonen und klatschten Applaus für Pflegekräfte. Für einen kurzen Augenblick konnte man den Eindruck gewinnen, dass das, was die Pflege in Deutschland leistet, endlich in den Köpfen der Menschen in diesem Land angekommen ist und sich so etwas wie eine Lobby etablieren könnte. Dazu beigetragen haben auch die vielen Statements von Politikern unterschiedlicher Couleur, welche sich teilweise überschlagen haben mit Vorschlägen und Ideen, was man nun alles für die Pflege tun müsse. Doch was ist daraus geworden, im Zuge der ersten überstandenen Corona-Pandemie-Welle und nun wieder prall gefüllten Toilettenpapierregalen? Nichts, jedenfalls nichts für die Pflege.
Infektionen unter Immunsuppression nach Nierentransplantation
Authors: Kemmner Stephan , Schönermarck Ulf
Published: October 2020

Unter immunsuppressiver Therapie besteht ein deutlich erhöhtes Infektionsrisiko nach Nierentransplantation (NTx), insbesondere für virale Infektionen. Bereits vor einer geplanten NTx sollte auf einen aktuellen Impfstatus geachtet werden, da nach einer Transplantation unter immunsuppressiver Therapie einerseits Lebendimpfstoffe nicht mehr gegeben werden dürfen und andererseits eine adäquate Impfantwort schwieriger zu erreichen ist. Die saisonale Influenzaimpfung kann bereits einen Monat nach Transplantation gegeben werden, für alle anderen Impfungen wird ein Abwarten von 3–6 Monaten empfohlen. Eine prophylaktische Therapie kann das Auftreten bestimmter Infektionen effektiv verhindern. Nach NTx sollte für die ersten 6 Monate eine PjP-Prophylaxe (PjP: Pneumocystis-jirovecii-Pneumonie) mit Trimethoprim/Sulfamethoxazol verabreicht werden. Eine CMV-Prophylaxe (CMV: Zytomegalievirus) mit Valganciclovir erfolgt in Abhängigkeit vom Sero-Status von Empfänger und Spender i. d. R. für 3 bzw. 6 Monate. Im Falle einer Infektion kann in Abhängigkeit vom Schweregrad der Antimetabolit (meist MMF: Mycophenolatmofetil) dosishalbiert oder pausiert werden, jedoch ist dies mit einem erhöhten Rejektionsrisiko verbunden. Insbesondere bei Infektionen mit CMV und BKV (Polyomavirus BK) kann anstelle von MMF ein mTOR-Inhibitor (mTOR: „mechanistic target of rapamycin“) eingesetzt werden in Kombination mit einem niedrigdosierten Calcineurininhibitor (CNI). Bei einer COVID-19-Erkrankung (COVID-19: Coronavirus Disease 2019) nach NTx sollte wie bei anderen Infektionen in einer Kombinationstherapie zunächst der Antimetabolit bzw. der mTOR-Inhibitor dosisreduziert oder pausiert werden. Ein Absetzen des CNIs bei COVID-19 erscheint aus unserer Sicht nicht regelhaft indiziert, sondern bleibt schweren Verläufen im Einzelfall vorbehalten. Im Falle einer antiviralen Therapie bei COVID-19 muss immer an mögliche Interaktionen mit den Immunsuppressiva (v. a. mit CNI und mTOR-Inhibitoren) gedacht werden.
Plädoyer für eine stärkere Integration der Psychotherapieforschung in die zukünftige Weiterbildung von Psychotherapeuten
Authors: Lutz Wolfgang , Schöttke Henning , Deisenhofer Anne-Katharina
Published: October 2020

In den letzten Jahren gibt es einen Wandel im Bereich theoretischer Neuentwicklungen in der Psychotherapie als auch in der Psychotherapieforschung zu verzeichnen. Neben der Untersuchung und Integration einer Vielzahl von gut bewährten störungsspezifischen Therapiekonzepten in die psychotherapeutische Praxis und Ausbildung von Psychotherapeutinnen und Psychotherapeuten
1
, hat sich ein transdiagnostisches Vorgehen sowie eine schulen- oder zumindest theorieübergreifende Ausrichtung bezüglich Kompetenzen und Wirkfaktoren herausgebildet. Zentral ist der Gedanke, dass ein positives Studienergebnis eines (theoretisch gut begründeten) Behandlungskonzeptes oder -programmes nicht automatisch die Richtigkeit der theoretischen Annahmen in Bezug auf Psychopathologie oder psychologischen Veränderungen zeigen kann.
„Robotik für gute Pflege“ – Hintergrund und Positionen des Deutschen Ethikrats
Authors: Kruse Andreas
Published: October 2020

Der Deutsche Ethikrat hat im März 2020 die Stellungnahme „Robotik für gute Pflege“ veröffentlicht. Andreas Kruse, Mitglied des Deutschen Ethikrats, fasst die wichtigsten Aspekte zusammen.
Patient Reported Outcomes (PROs) – a Tool for Strengthening
Patient Involvement and Measuring Outcome in Orthopaedic Outpatient
Rehabilitation
Authors: Müller Marcus , Brunssen Joscha , Messingschlager Martin
Published: October 2020

The present study serves to establish Patient Reported Outcomes (PROs) as a tool
for strengthening patient involvement and measuring outcomes in orthopaedic
outpatient rehabilitation. Assessments by FFbH-R (Hannover Back Function
Questionnaire for patients with back problems), Quick-DASH (Disabilities of Arm,
Shoulder, and Hand Score for patients with upper extremity lesions), and LEFS
(Lower Extremity Function Scale for patients with lower extremity lesions) were
employed in 20 outpatient rehabilitation centres over a period of 12 months to
evaluate changes in performance and participation from the subjective patient
perspective. The following questionnaires were used: FFbH-R status post: lumbar
disc surgery; cervical disc surgery; spinal canal decompression; conservative
back pain treatment; other; Quick-DASH status post: rotator cuff reconstruction;
shoulder arthroplasty; fracture (conservative or osteosynthesis); other; LEFS
status post: hip arthroplasty; knee arthroplasty; anterior cruciate ligament
repair; osteotomy; fracture (conservative treatment or osteosynthesis); other.
Analysis of the 6,751 usable data sets demonstrated significant positive changes
in all scores and diagnostic subgroups. The mean difference in score was 14.2
points in the FFbH-R, − 22 points in the Quick-DASH and 18 points in the LEFS.
Thus, this study proves the positive effects of orthopaedic rehabilitation in an
outpatient setting. PROs were instituted on a permanent basis in seven of the
participating institutions.
Robotic-Assisted Lobectomy Favors Early Lung Recovery versus Limited Thoracotomy
Authors: Lacroix Valérie , Kahn David , Matte Pascal , Pieters Thierry , Noirhomme Philippe , Poncelet Alain , Steyaert Arnaud
Published: October 2020

Background Postoperative pulmonary recovery after lobectomy has showed early benefits for the video-assisted thoracoscopic surgery and sparing open techniques over nonsparing techniques. Robotic-assisted procedures offer benefits in term of clinical outcomes, but their advantages on pulmonary recovery and quality of life have not yet been distinctly prospectively studied.

Methods Eighty-six patients undergoing lobectomy over a period of 29 months were prospectively studied for their pulmonary function recovery and pain score level during the in-hospital stay and at 1, 2, and 6 months. Quality of life was evaluated at 2 and 6 months. Forty-five patients were operated by posterolateral limited thoracotomy and 41 patients by robotic approach. The postoperative analgesia protocol differed for the two groups, being lighter for the robotic group.

Results The pulmonary tests were not significantly different during the in-hospital stay. At 1 month, the forced expiratory volume in 1 second, forced vital capacity, vital capacity, and maximal expiratory pressure were significantly better for the robotic group (p = 0.05, 0.04, 0.05, and 0.02, respectively). There was no significant difference left at 2 and 6 months. Pain intensity was equivalent during the in-hospital stay but was significantly lower for the robotic group at 1 month (p = 0.02). At 2 and 6 months, pain and quality of life were comparable.

Conclusion Robotic technique can offer similar pulmonary and pain recovery during the in-hospital stay with a lighter analgesia protocol. It clearly favors the early term recovery compared with the open limited technique. The objective and subjective functional recovery becomes equivalent at 2 and 6 months.
Management of Cutaneously Exposed Carotid Stents in Recurrent and Unresectable Head and Neck Cancer
Authors: Beer-Furlan André , Heilingoetter Ashley , Rayle Christopher , O'Toole Thomas , Nielsen Thomas J. , Crowley Richard Webster , Al-Khudari Samer
Published: October 2020

Objective Carotid blowout syndrome (CBS) is a rare but potentially life-threatening complication of head and neck cancer (HNC) treatment. Patients with CBS are managed with covered stents, limited published information exists regarding the management of delayed complications, specifically cutaneous exposure of stents. Here, we present our experience managing cutaneously exposed carotid artery stents (CAS) in patients with recurrent and unresectable HNC.

Methods A single-institution retrospective analysis was performed to identify recurrent HNC patients who underwent CAS placement for CBS and complicated with cutaneous exposure of the stent between 2014 and 2016. Medical records were reviewed with attention to treatment history, pre-, intra-, and postoperative courses, anticoagulation needs, and durability of the reconstruction.

Results We identified three patients who presented with a right CAS fully exposed in a large, ulcerative wound. All patients underwent a right pectoralis major myocutaneous flap (PMMF) to cover the exposed stent within 30 days of presentation to our institution. Two of three patients attained adequate coverage of the stent for more than 30 days, while one experienced partial flap dehiscence within 12 days. Two patients developed postoperative chest hematomas, which were managed conservatively. Two of three patients were able to undergo further palliative adjuvant treatments within 60 days of the initial surgical procedure.

Conclusion In this small series, durable coverage of an exposed carotid artery with PMMF was successful in two of three patients with extensive disease burden and complex prior treatment history. No mortalities occurred within 30 days postoperatively.
Illuminating interactions in light-based bioprinting
Authors: Patrick Chris
Published: October 2020

A review summarizes commonly used light-based bioprinting techniques and their underlying interactions between light and cells or polymers.
Load mitigation and wind power maximization of a HESG-based wind conversion system
Authors: Mseddi Amina , Le Ballois Sandrine , Aloui Helmi , Vido Lionel
Published: October 2020

This article discusses the control optimization of a hybrid generator-based wind conversion system (WCS). The optimization issues consider the maximization of the extracted wind power for the below-rated wind speeds and the load mitigation for high wind speeds. To do so, a DC/DC converter is used to realize the steady-state control of the generator's velocity through the adjustment of the excitation current, leading to maximization in the wind extracted power. As for the high wind speeds, a H∞ regulator implemented for the pitch control and a filter smoothing for the pitch angle reference are used to mitigate the load. Thanks to the implemented control strategy, the amplitude of the fluctuation of the bending moment was reduced by about 20% and the turbine torque vibration was reduced by 66% in comparison with other existing works from the literature conducted on the same wind turbine. The velocity controller is three times faster than the baseline controller and allows for increasing the wind extracted power by 6%. In this research, an integrated simulation platform, combining the electrical, mechanical, and aerodynamic aspects of a WCS, is set up. The space harmonics of the generator, the commutation effects of the power converters, the flexible coupling between the wind turbine's mechanical elements, and the aerodynamic interactions are taken into account. Finally, the control of the WCS in its full operating range is considered. The mechanical and aerodynamic data from the 1.5 MW WindPACT turbine available in the Fatigue, Aerodynamics, Structures, and Turbulence simulator are used for the simulations.
Large eddy simulations of airflow and particle deposition in pulsating bi-directional nasal drug delivery
Authors: Farnoud Ali , Tofighian Hesam , Baumann Ingo , Garcia Guilherme J. M. , Schmid Otmar , Gutheil Eva , Rashidi Mohammad Mehdi
Published: October 2020

Chronic rhinosinusitis is a common disease worldwide, and the frequently prescribed nasal sprays do not sufficiently deliver the topical medications to the target sites so that the final treatment in severe cases is surgery. Therefore, there is a huge demand to improve drug delivery devices that could target the maxillary sinuses more effectively. In the present study, different particle diameters and device pulsation flow rates, mainly used in pulsating aerosol delivery devices such as the PARI SINUS®, are considered to evaluate optimal maxillary sinus deposition efficiency (DE). Numerical simulations of the particle-laden flow using a large eddy simulation with a local dynamic k-equation sub-grid scale model are performed in a patient-specific nasal cavity. By increasing the pulsation flow rate from 4 l/min to 15 l/min, nasal DE increases from 37% to 68%. Similarly, by increasing the particle size from 1 µm to 5 µm, nasal DE increases from 34% to 43% for a pulsation flow rate of 4 l/min. Moreover, normalized velocity, vorticities, and particle deposition pattern in different regions of the main nasal cavity and maxillary sinuses are visualized and quantified. Due to the nosepiece placement in the right nostril, more particles penetrate into the right maxillary sinus than into the left maxillary sinus despite the maxillary ostium being larger in the left cavity. Lower pulsation flow rates such as 4 l/min improve the DE in the left maxillary sinus. The use of 3 µm particles enhances the DE in the right maxillary sinus as well as the overall total maxillary drug delivery.
Interaction Probability and Interaction Cross Section
Authors: Meli Jerome A.
Published: October 2020

Charged-particle beams are described in terms of fluence and energy fluence. The concept of interaction cross section is introduced to predict the probability and number of particles that interact with targets of a medium. The probability function is used to derive the mean free path of particles.
Production of X-ray Beams
Authors: Meli Jerome A.
Published: October 2020

This chapter discusses the production of x-ray beams from the bremsstrahlung interaction with nuclei. A description is given about how these beams are used in diagnostic imaging and radiation therapy.
Interactions and Dosimetry of Neutrons
Authors: Meli Jerome A.
Published: October 2020

Neutron interactions are discussed for fast and thermal neutrons. Kerma factor for fast neutrons and an expression for dose to tissue from thermal neutron capture are derived. Neutron beams are contaminated by photons, which adds complexity to dose measurements. The paired dosimeter method is described by means of an example of pairing an ionization chamber with LiF.
Multifunctional oxides for topological magnetic textures by design
Authors: Lim Z S , Ariando A
Published: October 2020

Several challenges in designing an operational skyrmion racetrack memory are well known. Among those challenges, a few contradictions can be identified if researchers are to rely only on metallic materials. Hence, expanding the exploration of skyrmion physics into oxide materials is essential to bridge the contradicting gap. In this topical review, we first briefly revise the theories and criteria involved in stabilizing and manipulating skyrmions, followed by studying the behaviors of dipolar-stabilized magnetic bubbles. Next, we explore the properties of multiferroic skyrmions with magnetoelectric coupling, which can only be stabilized in Cu2OSeO3 thus far, as well as the rare bulk Néel-type skyrmions in some polar materials. As an interlude section, we review the theory of the anomalous and topological Hall effect (THE), before going through the recent progress of THE in oxide thin films. The debate about an alternative interpretation is also discussed. Finally, this review ends with a future outlook regarding the promising strategies of using interfacial charge transfer and (111)-orientation of perovskites to benefit the field of skyrmion research.
Body-size-dependent Iodine-131 S values
Authors: Yeom Yeon Soo , Griffin Keith , Shin Bangho , Choi Chansoo , Han Haegin , Moon Sungho
Published: October 2020

In a recent epidemiologic risk assessment on late health effects of patients treated with radioactive iodine (RAI), organ/tissue doses of the patients were estimated based on iodine-131 S values derived from the reference computational phantoms of the International Commission on Radiological Protection (ICRP). However, the use of the S values based on the reference phantoms may lead to significant biases in the estimated doses of patients whose body sizes (height and weight) are significantly different from the reference body sizes. To fill this critical gap, we established a comprehensive dataset of body-size-dependent iodine-131 S values (rT ← thyroid) for 30 radiosensitive target organs/tissues by performing Monte Carlo dose calculations coupled with a total of 212 adult male and female computational phantoms in different heights and weights. We observed that the S values tend to decrease with increasing body height; for example, the S value (gonads ← thyroid) of the 160 cm male phantom is about 3 times higher than that of the 190 cm male phantom at the 70 kg weight. We also observed that the S values tend to decrease with increasing body weight for some organs/tissues; for example, the S value (skin ← thyroid) of the 45 kg female phantom is about two times higher than that of the 130 kg female phantom at the 160 cm height. For other organs/tissues, which are relatively far from the thyroid, in contrast, the S values tend to increase with increasing body weight; for example, the S value (bladder ← thyroid) of the 45 kg female phantom is about 2 times lower than that of the 130 kg female phantom. Overall, the majority of the body-size-dependent S values deviated to within 25% from those of the reference phantoms. We believe that the use of body-size-dependent S values in dose reconstructions should help quantify the dosimetric uncertainty in epidemiologic investigations of RAI-treated patients.
Heated thin film gauge arrangements to reduce uncertainty in transient heat transfer measurements
Authors: Usandizaga Inés , Beard Paul , Chana Kam , Povey Thomas
Published: October 2020

This paper describes the development of heated double-sided thin film gauge configurations for transient heat transfer measurements. By heating the substrate it is possible to measure the heat flux over a range of surface temperatures and deduce the adiabatic wall temperature and the external heat transfer coefficient. The accuracy of the measurement depends on the stability of the regression of heat flux against wall temperature and can be improved by extending the range of wall temperature over which the regression is performed. In this paper we compare two methods of local heating: double-sided gauges with an underside thin film heater and self-heating double-sided gauges. Both arrangements have been used in the Oxford Turbine Research Facility to measure the heat transfer on the uncooled turbine shroud of the MT1 high-pressure turbine stage at engine-representative conditions. These measurements yield improved regressions compared to conventional techniques to determine the adiabatic wall temperature and the heat transfer coefficient.
Quantum-cascade-laser-based dual-comb thermometry and speciation at high temperatures
Authors: Pinkowski Nicolas H , Cassady Séan J , Strand Christopher L , Hanson Ronald K
Published: October 2020

This work presents a methodology for using spectroscopic models to fit absorption-spectrum measurements made by a quantum-cascade-laser-based dual-comb spectrometer (QCL-DCS) for high-temperature kinetics research. A pair of quantum-cascade frequency combs was employed to detect methane’s

ν
4

absorption features between 1270 and 1320 cm−1 in high-temperature shock-tube environments and extract methane mole fraction and gas temperature from the results. The methodology was first validated by comparing DCS measurements against modeled methane spectra at room temperature in a static cell, followed by assessing the fitting procedure in shock-heated mixtures of 2% methane in Ar at 1000 K. In both validation experiments, the tradeoffs between time resolution and measurement precision were explored. Measurements were achieved at a 4 µs measurement rate with 5% uncertainty for temperature and 4% uncertainty for mole fraction at 1000 K. Higher accuracy was achieved with longer measurement averaging, e.g. 1.8% uncertainty for temperature at 40

μ

s resolution. Finally, the DCS spectral-fitting methodology was demonstrated to capture temperature and methane time-history evolution during the pyrolysis of iso-octane, a primary gasoline reference fuel. Good agreement was observed with kinetic models, and future applications for DCS kinetics research are discussed.
On the extraction of MoO
x
photothermally active nanoparticles by gel filtration from a byproduct of few-layer MoS2 exfoliation
Authors: Annušová Adriana , Bodík Michal , Hagara Jakub , Kotlár Mário , Halahovets Yuriy , Mičušík Matej , Chlpík Juraj , Cirák Július , Hofbauerová Monika , Jergel Matej , Majková Eva , Šiffalovič Peter
Published: October 2020

Gel filtration is a versatile technique employed for biological molecules and nanoparticles, offering their reproducible classification based on size and shape. Colloidal nanoparticles are of significant interest in biomedical applications due to a large number of solution-based bioconjugation procedures. Nevertheless, the inherent polydispersity of the nanoparticles produced by various techniques necessitates the employment of high yield separation and purification techniques. Here we demonstrate the employment of gel filtration on non-stoichiometric plasmonic MoO
x
nanoparticles, prepared by an oxidation process during liquid-phase exfoliation of few-layer MoS2 nanosheets. This resulted in the separation of two types of MoO
x
particles, in the form of two different chromatographic fractions. They showed different sizes, morphological and optical properties. The fraction containing smaller particles with diameters of 1–4 nm, exhibited an increased absorbance peak in the near IR region and responded with a significant temperature increase to laser irradiation at the wavelength close to the maximal absorption. The fraction with the larger particles from 3 up to 10 nm, showed weak photoluminescence and a preferred orientation upon the deposition on a planar substrate. However, it had no absorbance in the near IR compared to the former fraction. According to our knowledge, this is the first time that the gel filtration was applied to the separation of molybdenum oxide nanomaterials. This step ensured the isolation of plasmonic MoO
x
nanoparticles suitable for further bioconjugation and target photothermal treatment.
Photocatalytic hydrogen evolution activity over Pt-assisted metal-organic frameworks dominated by transition metal ions and local coordination environments
Authors: Li Lei , Wang Jia-Jun , Zhao Yan , Ding Bo , Wang Xiu-Guang , Zhao Xiao-Jun , Yang En-Cui
Published: October 2020

Three isostructural pillared-layer frameworks with M-BDC-X layers supported by ditopic HL connectors, [M(HL)(BDC)0.5X]
n
(HL = 4′-(4-hydroxyphenyl)-4,2′:6′,4″-terpyridine, BDC = terephthalate, M = Cd, X = Cl for (1), M = Cd, X = formate for (2), and M = Co, X = formate for (3)), were solvothermally synthesized, and used as photocatalysts for Pt-assisted visible-light-initiated hydrogen evolution from water splitting. These water-durable frameworks exhibit varied hydrogen production rates of 361.2, 271.3, and 327.5 μmol · g−1 · h−1 in 12 h due to their slightly different donor environments of the octahedral CdII and CoII ions. Further experimental and theoretical investigations reveal that the metal ions and the local coordination surroundings have essentially dominated the conduction band minimum and electric resistance of the charge transport, which play highly important roles for the improved catalytic hydrogen evolution ability. These findings demonstrate the electronic effect of the slightly ligand field modifications on the boosting hydrogen generation activity in the noble metal-assisted MOF photocatalytic systems.
Bi metal/oxygen-deficient BiO2−x
with tetrahedral morphology and high photocatalytic activity
Authors: Liang Mengjun , Zou Chentao , Wang Weihua , Yang Zhiyuan , Shen Kaixiang , Yang Yun , Yang Shuijin
Published: October 2020

Vacancy-rich materials with high photocatalytic activity are of great interest for pollutants removal and play a significant role in green chemistry. Herein, we successfully synthesized Bi/BiO2−x
composite through hydrothermal route. In this case, the surface plasmon resonance effect of Bi and oxygen vacancies of BiO2−x
collectively increase the removal rate of pollutants. More importantly, the Bi/BiO2−x
composites have enhanced activity in the degradation of RhB, MO, BPA and CIP, and the reduction of Cr(VI) and PNA. Besides, an enhanced photocatalytic activity is due to the main reactive species of ·

O

2

−

and h+ that is confirmed by trapping experiments and ESR analyses. The electronic structure and visible light harvesting of photocatalysts were measured and also theoretically calculated by using density functional theory and finite difference time domain calculations, DRS, VB x-ray photoelectron spectroscopy and Mott–Schottky plots, which allowed to propose a possible photocatalytic mechanism for the degradation process.
Alsedà–Misiurewicz systems with place-dependent probabilities*
Authors: Czudek Klaudiusz
Published: October 2020

We consider systems of two specific piecewise linear homeomorphisms of the unit interval, so called Alsedà–Misiurewicz systems, and investigate the basic properties of Markov chains which arise when these two transformations are applied randomly with probabilities depending on the point of the interval. Though this iterated function system is not contracting in average and known methods do not apply, stability and the strong law of large numbers are proven.
Is the Archimedes principle a law of nature? Discussions in an ‘extended teacher room’
Authors: Dahl Olof , Eklund Bo , Pendrill Ann-Marie
Published: October 2020

Is a suction cup at the bottom of a bathtub subject to an upward force from the surrounding water, even if there is no water under it? A student question, posted in a teacher facebook group on a Monday morning, led to a discussion involving 21 comments with 225 replies offered by 16 teachers during the next few days, including several simple experiments, as well as modeling, to evaluate different arguments. The discussions, summarized in this paper, provide an example of how social media can provide an ‘extended teacher room’ where teachers can explore and refine their understanding in a safe and mostly supportive environment, and also find ways to give more elaborate answers to challenging student questions.
Active contour regularized semi-supervised learning for COVID-19 CT infection segmentation with limited annotations
Authors: Ma Jun , Nie Ziwei , Wang Congcong , Dong Guoqiang , Zhu Qiongjie , He Jian , Gui Luying , Yang Xiaoping
Published: October 2020

Infection segmentation on chest CT plays an important role in the quantitative analysis of COVID-19. Developing automatic segmentation tools in a short period with limited labelled images has become an urgent need. Pseudo label-based semi-supervised method is a promising way to leverage unlabelled data to improve segmentation performance. Existing methods usually obtain pseudo labels by first training a network with limited labelled images and then inferring unlabelled images. However, these methods may generate obviously inaccurate labels and degrade the subsequent training process. To address these challenges, in this paper, an active contour regularized semi-supervised learning framework was proposed to automatically segment infections with few labelled images. The active contour regularization was realized by the region-scalable fitting (RSF) model which is embedded to the loss function of the network to regularize and refine the pseudo labels of the unlabelled images. We further designed a splitting method to separately optimize the RSF regularization term and the segmentation loss term with iterative convolution-thresholding method and stochastic gradient descent, respectively, which enable fast optimization of each term. Furthermore, we built a statistical atlas to show the infection spatial distribution. Extensive experiments on a small public dataset and a large scale dataset showed that the proposed method outperforms state-of-the-art methods with up to 5% in dice similarity coefficient and normalized surface dice, 10% in relative absolute volume difference and 8 mm in 95% Hausdorff distance. Moreover, we observed that the infections tend to occur at the dorsal subpleural lung and posterior basal segments that are not mentioned in current radiology reports and are meaningful to advance our understanding of COVID-19.
Deep convolution neural networks based artifact suppression in under-sampled radial acquisitions of myocardial T
1 mapping images
Authors: Nezafat Maryam , El-Rewaidy Hossam , Kucukseymen Selcuk , Hauser Thomas H , Fahmy Ahmed S
Published: October 2020

We developed a deep convolutional neural network (CNN) based method to remove streaking artefact from accelerated radial acquisitions of myocardial T
1-mapping images. A deep CNN based on a modified U-Net architecture was developed and trained to remove the streaking artefacts from under-sampled T
1 mapping images. A total of 2090 T
1-weighted images for 33 patients (55 ± 15 years, 19 males) and five healthy subjects (30 ± 14 years, 2 males) were used for training and testing the network. The images were acquired using radial slice interleaved T
1 mapping sequence (STONE) and retrospectively under-sampled to achieve acceleration rate of 4 (corresponding to 48 spokes). The dataset was split into training and testing subsets with 23 subjects (60%) and 15 subjects (40%), respectively. For generating voxel-wise T
1 maps, a two-parameter fitting model was used. Network performance was evaluated using normalized mean square error (NMSE), structural similarity index (SSIM) and peak signal-to-noise ratio (PSNR) metrics. The proposed network allowed fast (<0.3 s/image) removal of the artefact from all T
1-weighted testing images and the corresponding T
1 maps with PSNR = 64.3 ± 1.02, NMSE = 0.2 ± 0.09 and SSIM = 0.9 ± 0.3 × 10−4. There was no statistically significant difference between the measured T
1 maps for both per-subject (reference: 1085 ± 37 ms, CNN: 1088 ± 37 ms, p = 0.4) and per-segment (reference: 1084 ± 48 ms, CNN: 1083 ± 58 ms, p = 0.9) analyses. In summary, deep CNN allows fast and reliable removal of streaking artefact from under-sampled radial T
1 mapping images. Our results show that the highly non-linear operations of deep CNN processing of T
1 mapping images do not impact accurate reconstruction of myocardial T
1 maps.
Design of fiber-reinforced soft bending pneumatic artificial muscles for wearable tremor suppression devices
Authors: Wirekoh Jackson , Parody Nicholas , Riviere Cameron N , Park Yong-Lae
Published: October 2020

Soft robotics is a rapidly evolving field offering novel solutions in the development of wearable technologies. Soft pneumatic artificial muscles in particular, have seen widespread use in the development of human scale rehabilitative and assistive wearables. However, these soft actuators have not yet been adapted to address the complex dynamic regime of active (essential tremor) and resting (Parkinson’s disease) hand tremor, the most common movement disorder affecting humans. Current solutions to address hand tremor involve expensive medication and surgical interventions, as well as wearable assistive devices that fall short of providing an effective compact design for the suppression of hand tremor. This study focuses on the design of a novel lightweight, compact, bending actuator that will be capable of actively suppressing hand tremor when adapted into an assistive wearable device. The proposed fiber-reinforced bending pneumatic artificial muscle (BPAM), including its design specifications, fabrication process, theoretical modeling, and experimental characterization, are detailed. The developed actuator was capable of producing sinusoidal trajectories with peak-to-peak amplitudes of 40° and a bandwidth of 8 Hz, the dynamic regime of pathological hand tremor. The ability of the fiber-reinforced BPAM to act within the dynamic regime of hand tremor demonstrates its potential to be further developed into a system capable of the active suppression of hand tremor.
Complex imprint of solar variability on tree rings
Authors: Land Alexander , Kromer Bernd , Remmele Sabine , Brehm Nicolas , Wacker Lukas
Published: October 2020

Many studies have investigated the role of solar variability in Holocene climate. Beyond sunspot observations, solar activity can be reconstructed from 14C in tree rings. Due to the lack of sub-decadal resolution of 14C records, these studies focused on long-term processes. In this study, we use an annually-resolved 14C record to examine solar variability (e.g. 11-year Schwabe solar cycle) and its connection to European seasonal climate inferred from tree-ring records during the entire past millennium with spectral and wavelet techniques. The 11-year Schwabe solar cycle shows a significant impact in European moisture- and temperature-sensitive tree-ring records. Complex ’top-down’/‘bottom-up’ effects in the strato-tropoatmospheric system are assumed to affect European spring and summer climate with a temporal-shift as evident from observed changes in phase behavior. Significant evidence is also found for the ∼60- and ∼90-year band during the first half of the past millennium.
Text emotion mining on Twitter
Authors: Alkhushayni Suboh M , Zellmer Daniel C , DeBusk Ryan J , Alzaleq Du’a
Published: October 2020

Twitter has become a medium through which a substantial percentage of the global population communicates their feelings and reactions to current events. Emotion mining from text aims to capture these emotions by using a series of algorithms to evaluate the contents of each tweet. In this study, tweets that expressed at least one of seven basic emotions were collected. The resulting dataset was a corpus of 42,000 tweets with a balanced presence of each emotion. From this corpus a lexicon of roughly 40,000 words, each associated with a weighted vector corresponding to one of the emotions, was created. Next, different methods of identifying emotion in these ‘cleaned’ tweets were performed and evaluated. These methods included both lexically-based classification and supervised machine learning-based classification. Finally, an ensemble method involving several multi-class classifiers trained on unigram features of the lexicon was evaluated. This evaluation revealed that the ensemble method outperformed all other tested methods when tested on existing datasets as well as on the dataset created for this study.