bluuebunny/crossref_metadata_2025 huggingface dataset:
Restoring initial conditions in a deep argillaceous formation with induced suction on retrieval
Authors: Sau Nuria , Romero Enrique , Van Baelen Hervé
Published: October 2020

The deep and plastic Ypresian clays (Ycs) are one of the potential host rock formations in Belgium for the geological disposal of heat-emitting radioactive waste. Consequently, their thermo-hydro-mechanical behaviour has to be exhaustively studied at different depths. With this aim and considering that there is no underground research facility, deep core samples of Ycs have been retrieved between 300 and 450 m depth. The water-undrained sampling induces high matric suctions on the retrieved samples despite their nearly saturated state. Microstructural features, and particularly the larger dominant pore sizes with relatively low air-entry values, may also affect this induced suction. An experimental campaign has been launched to analyse the induced suction at different depths, which is complemented with pore size distributions carried out with mercury intrusion porosimetry. The study is accompanied by a constant volume test, in which a retrieved cylindrical sample with high initial suction is subjected to positive water pressure at the bottom boundary. The evolution of pore water pressure and total stress at different heights allows detecting the development of effective stress (swelling pressure) close to the initial suction. Finally, the paper emphasises the importance of following adequate experimental protocols on these high-suction samples to restorein situconditions.
Unsaturated Fluid Flow through Granular Soils Treated with Microbial Induced Desaturation and Precipitation
Authors: Young Elizabeth G. Stallings , Zapata Claudia E. , van Paassen Leon
Published: October 2020

The use of microorganisms to induce desaturation of granular soils via denitrification results in nitrogen and carbon dioxide gas generation, which in turn lowers the degree of saturation of the soil matrix. Given sufficient substrates, the stimulated bacteria will produce enough gas to develop a continuous gas phase. Introducing gas into the soil to reduce the degree of saturation is shown to increase the soil resistance to dynamic loading and helps to mitigate liquefaction. The impact of desaturation on liquefaction hazard mitigation has comparative value to the calcite precipitation phase of the process. Meso-scale tests have been performed on a relatively thin tank of soil to simulate planar flow through a granular soil treated with MIDP.
Comparison of experimental techniques for biocementation of sands considering homogeneous volume distribution of precipitated calcium carbonate
Authors: Centeno Dias Francisco , Borges Inês , Duarte Sofia O. D. , Monteiro Gabriel A. , Cardoso Rafaela
Published: October 2020

Microbially induced carbonate precipitation (MICP), or biocementation, consists in using microorganisms living in the soil to produce calcium carbonate (biocement). This mineral bonds the grains and therefore improves the soil hydro-mechanical properties. When using this technique, one of the challenges is to ensure homogeneous treatment in the entire volume. In this study, an experimental device was developed to apply this treatment in cylindrical soil samples with 7.2 cm diameter and 12 cm height. Two distinct sample preparation techniques were tested: (i) pre-mixing the soil with bacteria, and then inject the feeding solution; (ii) inject bacteria followed by injecting the feeding solution. In both, the injection conditions varied in two distinct ways: (i) infiltration column, from the top and (ii) injecting through a perforated central tube. The homogeneity of the biocement in the volume was evaluated using X-ray and SEM images from small samples taken from different locations in the specimens and analysing different parameters. Mercury intrusion porosimetry (MIP) and CaCO3 dissolution tests revealed uneven distribution of CaCO3 content between the top and bottom sections, as well as along radial direction. The most homogeneous samples were found when bacteria were premixed with the soil before injecting the feeding solution. Unconfined compression tests (UCS) were also performed in samples with and without treatment. The treatment increased stiffness and strength significantly and soil rupture occurred mostly near the bottom, where the lowest CaCO3 contents were detected.
Hydro-mechanical behaviour of alkali-activated binder treated soil
Authors: Vitale Enza , Marocco Antonello , Khatib Michael , Russo Giacomo
Published: October 2020

An experimental investigation on the mechanical improvement induced by alkali-activated binder based on the activation of a fluidal bed combustion fly ash on a clayey soil has been developed. The use of these binders for geotechnical applications is a promising issue in terms of sustainability since it reduces the carbon footprint and allows reusing secondary by-products such as artificial pozzolans. Treated samples were prepared by mixing soil and fly ash with water and alkaline solution and dynamically compacted. Mechanical behaviour has been investigated by means of triaxial tests performed on treated samples compacted at optimum water content. Addition of alkali activated binder increased stiffness and shear strength of treated samples, whose extent depends on binder content and curing time. Macroscopic behaviour of treated soil has been linked to the experimental evidences at microscale. Microstructural analyses highlighted a high reactivity of alkali-activated fly ashes as alumino-silicate source promoting the precipitation of new mineralogical phases with cementitious properties. Amorphous alumino-silicate gels produced from alkali-activation of fly ash bound particles aggregates leading to a decrease of cumulative pore volume and porosity of treated samples and modification of the modal pore size.
Water retention curves of lightweight cemented soils
Authors: Vitale Enza , Cuisinier Olivier , Russo Giacomo , Deneele Dimitri , De Sarno Domenico , Nicotera Marco Valerio , Papa Raffaele , Urciuoli Gianfranco
Published: October 2020

In the present paper an experimental investigation on water retention properties of lightweight cemented soils (LWCS) taking into account the effects of air foam content and curing time is presented. This experimental study, aimed at determining the suction range corresponding to significant changes in water content, is preliminary to future investigations devoted to durability properties of LWCS systems against wetting and drying cycles. Test results showed that water retention capacity is slightly affected by the curing time for the considered time interval (i.e. 30 and 90 days). Furthermore, the addition of air foam does not affect water retention properties of treated samples. Large voids are present in the samples as footprints of air bubbles added upon mixing, leading to an increase of the porosity of samples without altering the microstructure of the matrix.
Impact of wetting/drying cycles on the hydromechanical behaviour of a treated soil
Authors: Cuisinier Olivier , Masrouri Farimah
Published: October 2020

The positive effects of lime or cement treatment could be altered by weathering in the very long term. In this context, the main purpose of this study is to examine the impact of wetting/drying cycles on the strength and the hydraulic conductivity of a compacted soil treated with lime and cement. Compacted specimens were cured for 90 days before being exposed up to twelve wetting and drying cycles. A special concern of the study was the experimental method to impose the wetting and drying cycles. Two protocols were employed: one relied on relative humidity control to dry the samples, while the other was based on oven drying. The impact of the cycles was quantified by comparing the performance of the samples exposed to the cycles to the performance of the unsolicited samples. The results showed that the cycles induced a major alteration of the strength of the samples, with both methods. This degradation is associated to a significant increase of the hydraulic conductivity of the samples with the number of cycles.
Energetic electron precipitation and their atmospheric effect
Authors: Mironova Irina , Sinnhuber Miriam , Rozanov Eugene
Published: October 2020

Energetic particle precipitation induces ionization of the atmosphere which initiates a chain of reaction cycles affecting atmospheric composition and dynamics potentially down to surface weather systems. Ionization rates are retrieved based on yield functions or pre-calculated monoenergetic electron flux and energy spectra of precipitated energetic particles. Usually, information about energy spectra is obtained from satellites, balloons, and various ground-based observations. In all cases, some assumptions about spectral distribution for the entire energy range have to be made. As ionization rates are widely used in chemistry-climate models to estimate the atmospheric response to particle forcing, evaluation of the energy spectra is a key task in the solar-terrestrial studies. In this paper, it is shown that possible uncertainties of the ionization rates retrieval based on different spectral functions can lead to large disagreements in the ionization rates, with implications for the modelled response of atmospheric composition and dynamics to electron precipitation.
Variations of gamma-ray during thunderstorm by observations in Yakutsk
Authors: Toropov Anatoliy , Starodubtsev Sergey , Kozlov Vladimir , Balabin Juriy
Published: October 2020

The paper presents the results of a study of the increase in the gamma background in the surface layer of the atmosphere during near thunderstorms in Yakutsk (based on the Cosmic Ray Spectrograph of the IKFIA SB RAS). To register the gamma background, scintillation detectors based on NaI (Tl) crystals with a size of 63mm x 63mm are used. The range of measured energies is 20-1900 keV. The detectors are closed from the sides and bottom with lead (5 cm) and placed in thermoboxes with a glass window. The detector is located on the roof of the Cosmic Ray Spectrograph building in Yakutsk. Also, synchronous registration of the atmospheric electric field strength was carried out using an atmosphere electric field – mill sensor (with measurement range +/- 50 kV / m).The data of continuous recording of an analog signal from a detector during the nearest thunderstorms of 2018 were considered. The analog signal from the gamma detector was fed to the first channel of the E20-10 ADC (L-Card) and recorded continuously on the computer hard disk for one hour (during a thunderstorm) in series of 10 minutes. A signal from an active broadband dipole P-10 antenna (0.9 kHz - 900 MHz bandwidth) was fed to the second channel and was also recorded in one file together with the signal from the gamma detector. Synchronous recording of signals from the gamma detector and from the antenna allows accurate timing of gamma photons to electromagnetic signals from nearby lightning. In the studied thunderstorms, based on the results of the analysis of the data obtained, statistically significant variations in the count rate and shapes of the spectrum of gamma – ray at the moment of lightning discharges were found.
A model to calculate electrostatic charge structure of eruptive clouds from volcanic eruptions
Authors: Uvarov Vladimir , Akbashev Rinat , Firstov Pavel , Cherneva Nina
Published: October 2020

The paper proposes a model to calculate electrostatic charge structure of an eruptive cloud (EC) based on the response of atmospheric electric field (AEF EZ) strength during cloud passage near an observation site. The model provides high identity of calculated and experimental data for complex configurations of EC electrostatic charges. Examples of calculation of EC structures from Shiveluch volcano (Kamchatka) eruptions are given. They were estimated with the help of the developed model based on the records of AEF EZ response at the distances of 45 and 113 km.
Active impact on the ionosphere and variations of velocity characteristics of field-aligned irregularities
Authors: Sivokon Vladimir
Published: October 2020

Ionospheric irregularities make significant impact on the efficiency of radio-engineering system operation. Our investigations carried out on Kamchatka peninsula showed that field-aligned irregularities have particularly destructive influence on decame-ter radars. We pin some definite expectations with them to increase the efficiency ofradio-engineering systems by active impact on the ionosphere. One of the important parameters of such irregularities is their velocity characteristics. When determining irregularity velocity in the impact area, different approaches are used, for example, aspect scattering method which specifies velocity on the whole but does not allow one to determine its vertical and horizontal components, direction of its motion. We have developed an ap-proach which allows us to solve this problem. As an example, results of observations over EISCAT experiments in October 2019 are presented.
Dynamics and spatio-temporal distribution of geomagnetic disturbances during periods of increased solar activity and magnetic storms
Authors: Mandrikova Oksana , Rodomanskay Anastasia
Published: October 2020

A detailed spatio-temporal analysis of magnetic data was performed during the periods of magnetic storms on October 02, 2013 and September 27, 2019 based on measurements of the station network. In this work, we used a method developed by us for the analysis of magnetic data, based on the use of wavelet transform and adaptive thresholds. The method allows us to identify short-period field disturbances and estimate their intensity from the data of the H-component of the geomagnetic field. The features of the occurrence and propagation of geomagnetic disturbances in the auroral zone and at meridionally located stations have been studied. Dynamic spectra of disturbances of different intensity and duration are obtained. The paper confirms the possibility of occurrence of short-period weak geomagnetic disturbances at stations from high latitudes to the equator, preceding magnetic storms and correlating with fluctuations of the southern Bz-component of the interplanetary magnetic field and increases in the auroral indices of geomagnetic activity. Cross-correlation dependences of the intensity of geomagnetic disturbances on the parameters of the interplanetary medium during magnetic storms were obtained from the data of the network of magnetic stations. A statistically significant influence of the magnitude of the scope of the Bz-component of the IMF and the speed of the solar wind on the development of magnetic storms during the initial and main phases of magnetic storms was revealed.
Experimental investigations of acoustic field in sea shelf zone
Authors: Chernenko Vasiliy , Ven’tszyan’ Chen , Petrosyants Viktor , Garasev Ivan , Grishchenko Vladimir
Published: October 2020

Developed experimental facility allows one to generate acoustic pressure within the intervals from 105 to 106 Pa with an affective system of matching layers of bottom, water and ice. Theoretical and experimental investigations showed the possibility of information transfer in a shallow sea under an ice layer. Experimental acoustic system allows one to make measurements in a wide frequency range from 40 to 1100 Hz. The conducted investigation can be used to develop effective remote communication and to model earthquake acoustic precursor measurements.
Investigation of the channel for information transfer by electric, electromagnetic and acoustic waves in layered environment with ice cover
Authors: Korochentsev Vladimir , Syue Vey , Petrosyants Viktor , Em Artem , Garasev Ivan , Gubko Lyudmila
Published: October 2020

A theoretical model of electromagnetic wave propagation in an ice layer was developed. A half-wave vibrator frozen in an ice layer is used as a receiving-radiating system of electromagnetic waves. Schemes of developed acoustic low-frequency radiators based on electric sparks are described. The possibility of application of the developed systems to receive acoustic signals from earthquake ice source is under discussion.
Monitoring of Radiation Fields in Near Earth Space and Atmosphere in New Space Projects of Moscow University
Authors: Svertilov Sergey , Bengin Viktor , Bogomolov Vitaly , Garipov Gali , Dobynde Mikhail , Zolotarev Ivan , Кalegaev Vladimir , Кlimov Pavel , Osedlo Vladislav , Panasyuk Mikhail , Peretjat’ko Oleg , Petrov Vasily , Podzolko Mikhail
Published: October 2020

The Universat-SOCRAT project is developed in the Moscow State University aiming to forecast space-related risks for aviation, suborbital, and orbital flights and provide new knowledge on the magnetosphere and atmosphere of the Earth. An essential part of the system is a multi-satellite constellation, which would operate in the low-Earth orbit. Among other things, it would monitor the radiation and magnetic-wave environment in the vicinity of the Earth: in space and atmosphere. An Earth observation system, which operates in gamma and visible spectral range, should allow attribute detected changes in the environment to the atmospheric phenomena. We have already designed the instruments to detect increases in the flux of energetic charged particles (solar energetic particles, galactic cosmic rays, and electrons precipitating from radiation belts), geomagnetic disturbances, and electromagnetic transients in the atmosphere. The first stage of the program started on July 5, 2019, with a successful launch of three 3U CubeSats from the Vostochny cosmodrome. These satellites carry instruments for monitoring space radiation and prototype of the device for observing the Earth’s atmosphere in the ultraviolet range. The collected data has confirmed the advantages of multi-satellite observations for the goals of the project. During this year, we plan to launch two more 6U CubeSats with charged particle and gamma-ray detectors, magnetometers, and instrument for detecting of atmospheric electromagnetic transients. We suppose that these satellites will lay the foundation of the space threat monitoring system.
On the anisotropy of seismic waves in the Carpathian region
Authors: Lyskova Eugenia , Sannikov Konstantin
Published: October 2020

The anisotropy of seismic waves in the continental regions still belongs to the category of controversial issues, since its estimates in different areas show a different sign of the anisotropy coefficient. In contrast to studies of oceanic regions, where SH velocities always prevail over SV velocities, in the continental regions the relations between the velocities are very different. The explanation for this, first of all, is the difference in structure. The structure of the crust and upper mantle under the oceans is much more homogeneous in comparison with the structure of the continental regions. There are several approaches to the estimation of anisotropy. The most traditional method is to use the maximum amount of data separately for Love and Rayleigh waves to study the lateral distributions of SH- and SV-wave velocity, despite the fact that the density of the coverage by paths, and, consequently, the regions of best resolution can be of different shapes and sizes. It was decided to use this method as the first approximation in creating an anisotropic portrait of the Carpathian region. The Carpathian region was chosen as the object of study, since it contains interesting contrasting features: (1) the Pannonian Basin, which is characterized by a thin crust, a thinned lithosphere, and anomalously high values of the heat flux; (2) the Tornquist-Teisseyre zone, which is parallel to the strike of the Eastern Carpathians, and represents the contact zone of the Precambrian lithosphere of the EEP and the relatively young lithosphere of Western Europe. (3) The third feature is the Vrancea zone, one of the most active seismic zones in Europe. It is located in the junction of young tectonic structures: the Southern and Eastern Carpathians, the Transylvanian Depression and the Pre-Carpathian Depression. The results of the study confirm that the Tornquist-Teisseyre Zone divides the structures of the ancient East European Platform and orogenic zones of Western Europe: the upper mantle throughout EEP is characterized by high velocities, whereas velocities throughout WE are markedly lower. Low velocity anomalies prevail under Pannonian Basin which is characterized by anomalously high heat flow values. The distribution of the anisotropy coefficient demonstrates an extended layer of low values of the anisotropy coefficient at depths of 150-200 km. Above this layer, velocity distributions reveal the block structure of the lithosphere. The earthquake sources in the Vrancea zone fall into the transition zone from the highvelocity mantle under the EEP to the low-velocity mantle under the WE. Earthquakes do not occur below the revealed asthenospheric layer.
Some problems with old magnetic data processing
Authors: Khomutov Sergey Y. , Lingala Manjula
Published: October 2020

Continues magnetic measurements at the IKIR FEB RAS obser-vatories Magadan (MGD), Paratunka (PET), Yuzhno-Sakhalinsk (YSS), Cape Schmidt (CPS) and Khabarovsk (KHB) and CSIR-NGRI observatories Hyder-abad (HYB) and Choutuppal (CPL) have been started almost since their formation. A significant part of the results obtained is presented in the WDC and INTERMAGNET databases. However, a large amount of raw data remains un-processed and unavailable for using by scientific community. In the past few years, institutes has been making efforts to process and reprocess old magnetic data. Digital images of analog magnetograms of the Observatory Paratunka since 1967 were obtained and the possibility of their use for calculation hourly and minute values of magnetic field elements was evaluated. Old digital data that was available during the conversion from analog to digital magnetometers is processed. The main problem of processing or re-processing archived data is the lack of information (metadata) about the measurement conditions. First of all, these are the results of absolute observations, which are necessary to obtain the values of the elements of the total field vector. In this paper, some technologies are proposed that allow to use the data obtained during processing of analog magnetograms to adjust the digital magnetometers records. A signif-icant problem is the lack or inaccuracy of information about the temperature conditions in the variation pavilion, about magnetometers or support equipment maintenance or about works in and near the pavilions. As we accumulate the experience during the processing of old magnetic data, a “catalog” of noise and its typical images is formed. This makes it more reliable and efficient to identify and remove this noise from records.
Search for anomalies in pulse flows of acoustic and electromagnetic emissions
Authors: Senkevich Yury
Published: October 2020

Timely warning of disasters caused by earthquakes ensures life safety. Therefore, the search for markers of pre-seismic events preceding earthquakes remains an important research task. The article presents experimental methods for assessing seismic activity in the Kamchatka region based on the results of processing and analysis of geoacoustic and electromagnetic emission signals. The research is aimed at detecting anomalies in quantitative and qualitative indicators that characterize the pulse streams of acoustic emission of near-surface rocks and electromagnetic emission in the surface layer of the atmosphere. Signal processing and analysis are carried out using special algorithms that take into account the structural features of the variety of pulse shapes and their distribution over time.
Eosinophile Fasziitis – eine seltene Differenzialdiagnose bei venösen Symptomen
Authors: Dietze Lena , Metze Dieter , Goerge Tobias
Published: October 2020

Ein 26-jähriger Sportler stellte sich in unserer phlebologischen Ambulanz zur Diagnostik und Therapie bei sichtbarer Varikosis am linken Bein vor. Sonografisch stellte sich eine insuffiziente Vena saphena magna links dar. Es wurde eine VNUS-Closure der VSM links komplikationslos durchgeführt. Trotz sonografisch unauffälligen Kontrollen berichtet der Patient im weiteren Verlauf über ein zunehmendes Schweregefühl und eine Verhärtung der Haut. In der Histologie konnte eine eosinophile Fasziitis nachgewiesen werden. Bisher gibt es keine Berichte zum Zusammenhang von chronisch-venöser Insuffizienz, der endoluminalen Behandlung und eosionphiler Fasziitis. Der Fallbericht stellt eine seltene, aber in diesem Fall wichtige Differenzialdiagnose bei postinterventionellen venösen Beschwerden dar.
Statine und neue Therapieoptionen zur Behandlung der LDL-Hypercholesterinämie
Authors: Katzmann Julius L. , Laufs Ulrich
Published: October 2020

LDL-Cholesterin ist ein etablierter kausaler Risikofaktor für atherosklerotische kardiovaskuläre Erkrankungen. In aktuellen Leitlinien wird eine Senkung des LDL-Cholesterins auf Zielwerte abhängig vom kardiovaskulären Risiko empfohlen. Um die Zielwerte zu erreichen, wird eine Stufentherapie aus Lebensstil, Statinen, Ezetimib und den PCSK9-Inhibitoren angeraten. Zukünftige Therapieoptionen zur Senkung des LDL-Cholesterins bestehen u.a. in Bempedoinsäure, welche den Metabolismus ähnlich beeinflusst wie Statine, ohne jedoch im Muskel verstoffwechselt zu werden, und in Inclisiran, welches die Produktion von PCSK9 intrazellulär blockiert und nur alle 6 Monate gespritzt werden muss. Die Ergebnisse der laufenden Endpunktstudien zu beiden Substanzen stehen noch aus. Diese neuen Wirkstoffe könnten insbesondere bei Patienten mit Muskelschmerzen oder schlechter Therapieadhärenz zukünftig eine Ergänzung der therapeutischen Möglichkeiten darstellen.
Stellenwert komplementärer Supportivtherapie bei immunsupprimierten onkologischen Patienten – Eine Kasuistik
Authors: Holzhauer Peter , Gröber Uwe , Kisters Klaus
Published: October 2020

Die hochdosierte parenterale Applikation von Vitamin C ist eine von zahlreichen komplementärmedizinischen Methoden, die häufig zur Behandlung von tumorassoziierter Fatigue-Symptomatik und als komplementäre Supportivtherapie – auch jetzt in der Phase der COVID-19-Pandemie – zur Immunstimulation und als antivirale Option eingesetzt wird. Die hier vorgestellte Kasuistik beschreibt neben einer folgenreichen Wechselwirkung dieser medikamentösen supportiven Therapie mit einem Hightech-Medizinprodukt auch moderne konventionelle Therapieoptionen beim triple-negativen Mammakarzinom. Dabei kommen verschiedene immunrelevante Mikronährstoffe zum Einsatz, die einerseits die moderne Checkpoint-Inhibition mit Atezolizumab unterstützen und andererseits eine möglichst optimale Abwehrlage in der Phase der Pandemie gewährleisten sollen. Aktuelle Daten wurden zu dieser Thematik gerade für Selen und Vitamin D publiziert.
Simultaneous Application of Ultrasound and Sialendoscopy and its Value in the Management of Sialolithiasis
Authors: Koch Michael , Schapher Mirco Lothar , Mantsopoulos Konstantinos , Goncalves Miguel , Iro Heinrich
Published: October 2020

Objective Ultrasound (US) and sialendoscopy (SE) are routinely used in patients presenting with sialolithiasis in the submandibular (SMG) and parotid gland (PG). The objective was to assess the value of the simultaneous application of US and SE in the management of sialolithiasis.

Study Design Retrospective study. Setting: Tertiary referral center for salivary gland diseases. Participants: Patients in whom US and SE as single investigation tools were neither conclusive nor useful in the management of sialolithiasis were investigated using both methods simultaneously (simUS + SE). Main outcome measures: Establishment of the final diagnosis and/or contribution to the planning/performing of treatment in sialolithiasis.

Results 74 patients were examined by simUS + SE (58.1 % SMG and 41.9 % PG). In all patients (unclear) hyperechoic reflexes were assessed and/or localized by SE-controlled US navigation. 68.9 % of the patients were investigated for diagnostic or differential-diagnostic reasons including distinguishing extraductal from intraductal calcifications and/or to exclude residual stones after therapy. In 52.7 % simUS + SE was used to plan and/or perform further treatment, in 20.3 % to enable performing a combined approach (all PG) and in 29.7 % to evaluate and plan the most adequate therapy (mainly intraductal vs. extracorporeal shock wave lithotripsy, 68.2 % of these SMG). In two cases SE-controlled and US-guided stone extraction was performed.

Conclusion SimUS + SE is an innovative approach which proved to be very useful in managing sialolithiasis. It added valuable information regarding the establishment of a diagnosis or differential diagnosis, planning and performing the most adequate treatment, intraoperative control of therapy and postoperative follow-up.
Cerebral Autoregulation and Neurovascular Coupling after Craniospinal Irradiation in Long-Term Survivors of Malignant Pediatric Brain Tumors of the Posterior Fossa
Authors: Janzarik Wibke G. , Sander Milena , Rößler Jochen , Sommerlade Linda , Allignol Arthur , Reinhard Matthias
Published: October 2020

Introduction Long-term survivors of craniospinal irradiation have an increased risk for stroke which increases with radiation dose and follow-up time. Radiotherapy induces structural changes of the cerebral vasculature, affecting both, large, and small vessels. It is unknown how these structural changes affect functional mechanisms of cerebral blood flow regulation such as cerebral autoregulation and neurovascular coupling.

Methods Using the transcranial Doppler, we compared dynamic cerebral autoregulation and neurovascular coupling of 12 patients after long-term survival of craniospinal irradiation due to a malignant pediatric brain tumor of the posterior fossa and 12 age- and sex-matched healthy patients. Mean arterial blood pressure and cerebral blood flow velocities in the middle and posterior cerebral artery were recorded at rest during normal breathing to assess cerebral autoregulation (transfer function parameters phase and gain, as well as the correlation coefficient indices Mx, Sx, and Dx), and during 10 cycles of a visual task to assess neurovascular coupling (parameters time delay, natural frequency, gain, attenuation, and rate time).

Results Parameters of cerebral autoregulation showed a consistent trend toward reduced cerebral autoregulation in patients that did not reach statistical significance. Neurovascular coupling was not altered after craniospinal irradiation.

Conclusion In this pilot study, we demonstrated a trend toward reduced cerebral autoregulation, and no alteration of neurovascular coupling after irradiation in long-term survivors of malignant pediatric brain tumors of the posterior fossa.
Effect of Screw Insertion Torque on Mechanical Properties of a Hybrid Polyaxial Locking System
Authors: Jung Hye-Jin , Jang Aram , Yim Hyeong-Jun , Han Chang-Hoon , Lee Jae-Hoon
Published: October 2020

Objective The aim of this study was to determine the effect of insertion torque and angulation on the push-out strength of screws in Atraumatic Rigid Fixation (ARIX) system.

Materials and Methods In vitro mechanical tests of the ARIX system were conducted. Screw plate constructs (n = 120) were tested using five different insertion torques at four different angles relative to the perpendicular axis of the plate. Before the push-out test, screws were locked into the plates, and the push-out force of the screw was measured by applying a load parallel to the screw axis.

Results Implant failure was observed at 0.8 Nm at an insertion angle of 15 degrees, and at 1 Nm at 0 degree, 5 degrees and 10 degrees. Two types of failures were observed: cold welding and plate deformation. An insertion torque of 0.8 Nm produced a significantly higher push-out force compared with 0.2 Nm. Non-angled specimens with 0.8 Nm insertion torque exhibited significantly higher screw push-out forces compared with other tested specimens and insertion angles. Insertion angle did not affect screw push-out force at insertion torques of 0, 0.2, 0.4 and 0.6 Nm.

Conclusion The ARIX locking system is much more sensitive to insertion torque than angle. An effect of insertion angle was observed only at an insertion torque of 0.8 Nm, under which all angles significantly decreased push-out force relative to zero degrees of angulation. In addition, low insertion torques can result in screws loosening over time, while greater insertion torques than 1 Nm can result in screw head stripping and plate hole deformation.
Pain Relief after Surgical Decompression of the Distal Brachial Plexus
Authors: Morgan Richard , Elliot Iain , Banala Vibhu , Dy Christopher , Harris Briana , Ouellette Elizabeth Anne
Published: October 2020

Background Brachial plexopathy causes pain and loss of function in the affected extremity. Entrapment of the brachial plexus terminal branches within the surrounding connective tissue, or medial brachial fascial compartment, may manifest in debilitating symptoms. Open fasciotomy and external neurolysis of the neurovascular bundle in the medial brachial fascial compartment were performed as a surgical treatment for pain and functional decline in the upper extremity. The aim of this study was to evaluate pain outcomes after surgery in patients diagnosed with brachial plexopathy.

Methods We identified 21 patients who met inclusion criteria. Documents dated between 2005 and 2019 were reviewed from electronic medical records. Chart review was conducted to collect data on visual analog scale (VAS) for pain, Semmes-Weinstein monofilament test (SWMT), and Medical Research Council (MRC) scale for muscle strength. Pre- and postoperative data was obtained. A paired sample t-test was used to determine statistical significance of pain outcomes.

Results Pain severity in the affected arm was significantly reduced after surgery (pre: 6.4 ± 2.5; post: 2.0 ± 2.5; p < 0.01). Additionally, there was an increased response to SWMT after the procedure. More patients achieved an MRC rating score ≥3 and ≥4 in elbow flexion after surgery. This may be indicative of improved sensory and motor function.

Conclusion Open fasciotomy and external neurolysis at the medial brachial fascial compartment is an effective treatment for pain when nerve continuity is preserved. These benefits were evident in patients with a prolonged duration elapsed since injury onset.
Design and optimization of a proportional counter for the absolute determination of low-energy x-ray emission rates
Authors: H. Elvira V. , Roteta M. , Fernández-Sotillo A. , García-Toraño E.
Published: October 2020

We recently presented the construction of a proportional counter for the absolute measurement of low-energy x-ray emission rates. Its main features were presented in a previous study, along with the testing of its performance as an absolute technique. Full details on its design, construction, and characterization processes are given in this paper. First, the analytical calculations and Monte Carlo simulations that led to the choice of optimal dimensions will be presented, followed by the study of the charge creation and the modeling of the electric field that confirmed that the criteria for a reproducible charge multiplication are met. Afterward, details on the electronics and gas control system will be provided. The dimensional measurements for the accurate determination of the solid angle will be described in detail. Special emphasis will be placed on the production of the detector window, which was made of reduced graphene oxide instead of beryllium. Some tests on the operation of the counter will be presented, namely, the measurement of spectra of several radionuclides that emit x-rays between 3 keV and 9 keV, as well as the fluorescence spectrum of chlorine, at 2.6 keV. A brief explanation of the determination of emission rates will be given, including the approach adopted for the treatment of the escape-peak area. The emission rate measured with the proportional counter was converted into activity concentration using the emission probabilities from the bibliography, in order to compare the results with those obtained by liquid scintillation counting, and both results were found to be in good agreement.
A new method for high-bandwidth servo control of the power ratio between two Raman beams for cold atom interferometer
Authors: Wang Yaning , Zhang Huankai , Xu Dongyang , Yan Shuhua , Li Qixue , Zhang Xu , Lv Mengjie , Wang Guochao , Jia Aiai , Zhu Lingxiao , Yang Jun
Published: October 2020

Light shift produced by the AC Stark effect is one of the major factors limiting the accuracy and long-term stability of a cold atom interferometer. The first order light shift can be canceled by fixing the power ratio of the Raman beams at a specified value. We report here a new method to stabilize the power ratio of the two Raman lasers with ∼100 kHz locking bandwidth, suppressing the effect of the first order light shift. We first mixed the two Raman lasers (at different optical frequencies) with a reference beam and then used two Schottky diode detectors to extract the corresponding beat note signals for each beam, which are much easier to be manipulated and processed as they are in the microwave band. The stability of the power ratio is improved by three orders of magnitude from 5.84 × 10−3 to 3.51 × 10−6 at 1 s averaging time and reaches 1.59 × 10−7 at 10 000 s integrating time when the servo loop is engaged. This method can be used in other precise quantum measurement based on the stimulated Raman transition and can be applied to compact inertial sensors.
The flush development of evergreen recurrent flushing perennials: an experimental overview with insights into the flowering of olive
Authors: Olesen Trevor , Wirthensohn Michelle
Published: October 2020

Recurrent flushing perennials are those that grow by episodic waves of shoot extension under conditions continuously favourable for growth. Here we review the habit for evergreen perennials. The commencement of a new flush appears to depend on the stimulation of buds by plant growth regulators. The determination of a new flush as vegetative or floral most likely occurs during early shoot development. Cool temperatures are usually florally inductive, but other factors such as periods of water stress before flush commencement, and low crop loads may also enhance induction. There is little evidence for the control of the final size of vegetative shoots, and even less for the size of floral shoots. The time between successive flushes is cyclic and temperature dependent. New work with olive is presented and shows that pruning increases the proportions of vegetative shoots to develop from comparable nodes of pruned and non-pruned branches. It also shows that immature vegetative flushes on olive branches in winter inhibit flowering to some extent, a result previously shown for other evergreen recurrent flushing trees.
Language attitudes and L2 pronunciation
Authors: Roberts Gillian
Published: October 2020

Since pronunciation serves as a vehicle for both intelligibility and identity, exploring learners’ attitudes towards different accent varieties can allow both pedagogical and sociolinguistic insights into second language acquisition. This study investigates the attitudes of Flemish secondary school students towards RP and General American and the relation between these attitudes and the students’ actual pronunciation in English. Participants rated British and American accents in a verbal guise experiment, and speech recordings provided a sample of respondents’ own pronunciation. Results diverged from previous findings: while participants had more positive attitudes towards RP, they spoke with a higher proportion of GA phonological features. Almost half of the participants did not aim to speak with either a British or an American accent.
Moving simply: Naegleria crawls and feeds using an ancient Arp2/3-dependent mechanism
Authors: Baum Buzz , Dey Gautam
Published: October 2020

Arp2/3-nucleated actin filaments drive crawling motility and phagocytosis in animal cells and slime molds. In this issue, Velle and Fritz-Laylin (2020. J. Cell Biol.https://doi.org/10.1083/jcb.202007158) now show that Naegleria gruberi, belonging to a lineage that diverged from opisthokonts around a billion years ago, uses similar mechanisms to crawl and phagocytose bacteria.
Teaching general physics in a COVID-19 environment: insights from Taiwan
Authors: White Jonathon David
Published: October 2020

COVID-19 has upset the traditional ways of teaching and looks set to continue to have an impact in the coming years. The situation in Taiwan—partial disruption and then an early return to classes—allows for a comparison of student performance in a conventional teaching and testing environment with the non-contact teaching/testing environment caused by COVID-19. For the part of the general physics class delivered remotely, test marks dropped uniformly across the whole class from 69% to 46% from the previous year. Poorer knowledge acquisition was not just limited to poor students but surprisingly equally affected those at the top of the class as well. In contrast, remote testing resulted in a higher overall grade—due to ∼5% of the ∼70 students enrolled scoring significantly better on unsupervised tests (>93% vs ∼40% on three supervised tests). The marks for the remaining 95% of students were consistent with their overall performance. An advantage of moving to online lectures is the ability to archive lectures. Our research indicates that students take advantage of these online lectures: both in reviewing in the days immediately after the class and immediately prior to testing.
High-density electron–ion bunch formation and multi-GeV positron production via radiative trapping in extreme-intensity laser–plasma interactions
Authors: Capdessus R , Gremillet L , McKenna P
Published: October 2020

Multi-petawatt laser systems will open up a novel interaction regime mixing collective plasma and quantum electrodynamic processes, giving rise to prolific generation of gamma-ray photons and electron–positron pairs. Here, using particle-in-cell simulations, we investigate the physics of the interaction of a 1024 W cm−2 intensity, 30 fs duration, circularly polarized laser pulse with a long deuterium plasma at classically overcritical electron density (1022 cm−3). We show that radiative trapping of the plasma electrons causes a high-density (∼5 × 1023 cm−3), quasineutral electron–ion bunch to form inside the laser pulse. This phenomenon is accompanied by up to ∼40% energy conversion efficiency of the laser into gamma rays. Moreover, we find that both the radiation-modified Laplace force and the longitudinal electric field exerted on the positrons created by the multiphoton Breit–Wheeler process can accelerate them to GeV-range energies. We develop a theoretical model, the predictions of which provide a good match to the simulation results. Finally, we address the influence of the ion mass, showing that the laser absorption and positron acceleration is enhanced with deuterons compared to protons.
Chiral magnetic effect at finite temperature in a field-theoretic approach
Authors: Beneventano C G , Nieto M , Santangelo E M
Published: October 2020

We investigate the existence (or lack thereof) of the chiral magnetic effect (CME) in the framework of finite temperature field theory, studied through the path integral approach and regularized via the zeta function technique. We show that, independently of the temperature, gauge invariance implies the absence of the effect, a fact proved, at zero temperature and in a Hamiltonian approach, by Yamamoto. Indeed, the effect only appears when the manifold is finite in the direction of the magnetic field and gauge-invariance breaking boundary conditions are imposed. We present an explicit calculation for antiperiodic and periodic boundary conditions, which do allow for a CME, since only ‘large’ gauge transformations are, then, an invariance of the theory. In both cases, the associated current does depend on the temperature, a well as on the size of the sample in the direction of the magnetic field, even for a temperature-independent chiral chemical potential. In particular, for antiperiodic boundary conditions, the value of this current only agrees with the result usually quoted in the literature on the subject in the zero-temperature limit, while it decreases with the temperature in a well-determined way.
Doravirine/Lamivudine/Tenofovir Disoproxil Fumarate (TDF) Versus Efavirenz/Emtricitabine/TDF in Treatment-naive Adults With Human Immunodeficiency Virus Type 1 Infection: Week 96 Results of the Randomized, Double-blind, Phase 3 DRIVE-AHEAD Noninferiority Trial
Authors: Orkin Chloe , Squires Kathleen E , Molina Jean-Michel , Sax Paul E , Sussmann Otto , Lin Gina , Kumar Sushma , Hanna George J , Hwang Carey , Martin Elizabeth , Teppler Hedy
Published: October 2020

Background

Doravirine (DOR) is a nonnucleoside reverse-transcriptase inhibitor. In the phase 3 DRIVE-AHEAD trial in treatment-naive adults with human immunodeficiency virus type 1 (HIV-1) infection, DOR demonstrated noninferior efficacy compared with efavirenz (EFV) and superior profiles for neuropsychiatric tolerability and lipids at 48 weeks. We present data through week 96.

Methods

DRIVE-AHEAD is a phase 3, multicenter, double-blind, noninferiority trial in antiretroviral treatment-naive adults with HIV-1 RNA ≥1000 copies/mL. Participants were randomized to a daily fixed-dose tablet of DOR (100 mg), lamivudine (3TC; 300 mg) and tenofovir disoproxil fumarate (TDF; 300 mg) (DOR/3TC/TDF) or EFV (600 mg), emtricitabine (FTC; 200 mg) and TDF (300 mg) (EFV/FTC/TDF). The efficacy end point of interest at week 96 was the proportion of participants with HIV-1 RNA levels <50 copies/mL (Food and Drug Administration Snapshot Approach) with a predefined noninferiority margin of 10% to support week 48 results. Safety end points of interest included prespecified neuropsychiatric adverse events and the mean change in fasting lipids at week 96.

Results

Of 734 participants randomized, 728 received study drugs and were included in analyses. At week 96, HIV-1 RNA <50 copies/mL was achieved by 77.5% of DOR/3TC/TDF vs 73.6% of EFV/FTC/TDF participants, with a treatment difference of 3.8% (95% confidence interval, –2.4% to 10%). Virologic failure rates were low and similar across treatment arms, with no additional resistance to DOR observed between weeks 48 and 96. Prespecified neuropsychiatric adverse events and rash were less frequent in DOR/3TC/TDF than in EFV/FTC/TDF participants through week 96. At week 96, fasting low-density lipoprotein cholesterol and non–high-density lipoprotein cholesterol (HDL-C) levels increased in the EFV/FTC/TDF group but not in the DOR/3TC/TDF group; the mean changes from baseline in total cholesterol/HDL-C ratio were similar.

Clinical Trials Registration

NCT02403674.