bluuebunny/crossref_metadata_2025 huggingface dataset:
Stainless steel matrix composites reinforced with ceramic particles through ingot casting process
Authors: Kračun Ana , Tehnovnik Franc , Kafexhiu Fevzi , Kosec Tadeja , Jenko Darja , Podgornik Bojan
Published: August 2018

The aim of the study was to assess the influence of adding Al2O3 nano-particles of 0.5 wt. % with the mean particle size of 500 nm on the mechanical properties and wear behaviour of the austenitic stainless steel matrix reinforced with nano-particles produced by conventional ingot casting. The focus was on the methods and possibilities of homogeneous and uniform distribution of the particles within the steel matrix using conventional casting routes. The main drawback of the casting method used is the agglomeration of the particles and poor interface between the particles and the metal matrix. The results show that through a proper insertion method, nano-particles can be successfully introduced into the metal matrix. The Al2O3 nano-particles were successfully incorporated into the steel matrix with no signs of clustering and intermetallic reactions taking place between the nano-particles and the steel matrix. This led to improved mechanical properties as well as the wear behaviour of the stainless steel, achieved by using conventional casting routes.
A Fractographical Study on Dissimilar Weld Joints of SAF 2205 and Hastelloy C-276
Authors: Çelikkol Emrullah , Tümer Mustafa , Atapek Ş. Hakan , Kerimak M. Zaim
Published: August 2018

In this study, a dissimilar weld joint between SAF 2205 and Hastelloy C-276 was manufactured by using gas tungsten arc welding and its notched impact fracture behaviour was investigated. Initially, V-type welding mouth was opened and the welding was performed by multi-pass. In welding procedure, ERNiCrMo-3 material used as a filler metal and the heat input was varied between 0.48-1.10 kJ/mm depending on welding parameters. Both welding pool and root zone were protected by an argon atmosphere. Multi notched impact tests were performed at room temperature. Weld metal had an impact toughness value as 92 J and its fracture surface exhibited several oriented cracking paths due to its solidified structure. The impact toughness value was measured as 82 J for heat affected zone of SAF 2205 and its fractograph reflected the coarser and deeper dimples. Heat affected zone of nickel based alloy had the highest impact toughness value as 116 J among the studied joints due to the more plastic deformation capability of nickel having face centered cubic structure, however, its fracture surface under impact loading exhibited several cracks propagating throughout the fusion line having equiaxed dendrites.
Weniger akute Atemwegsinfekte durch Vitamin-D-Supplementation?
Authors: Weckbecker Klaus
Published: August 2018

Martineau AR. et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data.
BMJ 2017; 356: i6583

Vitamin D spielt Studien zufolge auch eine Rolle bei der Abwehr pathogener Keime: 25-Hydroxy-Vitamin D (25[OH] Vitamin D) unterstützt z. B. die Synthese
antimikrobieller Peptide. Es gibt also eine mögliche Erklärung für die Beobachtung, dass Personen mit niedrigen Vitamin-D-Spiegeln besonders empfindlich
gegenüber respiratorischen Infekten sind. Untersuchungen zu einer präventiven Wirkung des Vitamin D verliefen jedoch zum Teil widersprüchlich.
Einfluss des Besuchs einer Kindertagesstätte (Kita) auf den Entwicklungsstand bei Vorschulkindern
Authors: Knollmann Carla , Thyen Ute
Published: August 2018

Hintergrund Die Zahl außerfamiliärer Betreuungsangebote für Klein- und Vorschulkinder wurde in den letzten Jahren erweitert. Neben arbeitsmarktpolitischen Zielen sollte damit auch die Chancengleichheit für Kinder verbessert werden. Die Studie untersuchte, wie sich die Kitabesuchsdauer unter Berücksichtigung sozialer Determinanten auf die Entwicklung eines Kindes auswirkt.

Methoden Daten aus der schleswig-holsteinischen Schuleingangsuntersuchung der Jahre 2014–2015 von 21 272 Kindern im Alter von 5–6 Jahren wurden hinsichtlich bildungsrelevanter Zielgrößen, soziodemografischer Merkmale sowie des Kitabesuchverhaltens analysiert.

Ergebnisse Ein niedriger Bildungsstand der Familie, eine Migrationsbiografie beider Eltern, ein Aufwachsen mit vielen Geschwistern und eine Erziehung durch Alleinerziehende waren mit Auffälligkeiten der Zielgrößen assoziiert (p<0,01). Eine Kitabesuchsdauer von länger als zwei Jahren erwies sich als optimal. Logistische Regressionsanalysen ergaben (Odds-Ratios [95%-Konfidenzintervall]): Mit jedem Kitabesuchsjahr reduzierten sich Auffälligkeiten der Motorik (0,84 [0,79–0,9]), der Kognition (0,7 [0,66–0,73]) und der Sprache (0,91 [0,86–0,96]), mäßiger (pädagogischer) (0,85 [0,79–0,91]) und sonderpädagogischer Förderbedarf (0,58 [0,54–0,64]) sowie unzureichende Deutschkenntnisse (0,42 [0,35–0,5]) bei Schuleintritt auch unter Berücksichtigung sozialer Determinanten. Bezüglich des Auftretens von Übergewicht bestand kein signifikanter Zusammenhang mit der Kitabesuchsdauer.

Schlussfolgerungen Der Besuch einer Kita wirkt sich positiv auf die Kindesentwicklung aus. Hierbei profitieren insbesondere sozial benachteiligte Kinder von einem Kitabesuch. Interventionsprogramme innerhalb des Settings Kita sind daher begrüßenswert.
Ultrasonography Classification of the American Thyroid Association for Predicting Malignancy in Thyroid Nodules >1cm with Indeterminate Cytology: A Prospective Study
Authors: Rocha Tiara , Rosario Pedro , Silva Alexandre , Nunes Maurício , Silva Tulio , de Oliveira Pedro , Calsolari Maria
Published: August 2018

The objective of this prospective study was to evaluate the ultrasonography classification of the American Thyroid Association (ATA) for predicting malignancy in thyroid nodules >1 cm with indication for fine-needle aspiration (FNA) whose cytology was indeterminate. Additionally, the combination of the ATA classification with Doppler analysis was evaluated. All patients with thyroid nodules >1 cm were eligible. Each nodule was assigned to one of the ATA categories. Exclusively or predominantly intranodular vascularity was considered suspicious. One hundred and thirty-seven patients with 143 nodules underwent FNA and those with indeterminate cytology (Bethesda category III or IV) were selected. All patients were referred for surgery. Among the 143 nodules evaluated, 92 were benign, 33 were malignant, 13 were noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP), and 5 were tumors of uncertain malignant potential (TUMP). The rate of malignancy, including NIFTP and TUMP in this definition, was 80%, 42.8%, 13%, 10%, and 23% for nodules with a high suspicion, intermediate suspicion, low suspicion, very low suspicion, and undefined ultrasonographic pattern, respectively. Considering NIFPT and TUMP as benign, these rates were 72%, 22.4%, 4.3%, 0%, and 15.4%, respectively. The addition of Doppler analysis did not significantly improve the prediction of malignancy obtained with the ATA classification alone. The results of this prospective study show the usefulness of the ATA ultrasonographic classification for predicting malignancy specifically in thyroid nodules >1 cm with indeterminate cytology. The ATA category of the nodule should influence the decision for follow-up, molecular tests, or surgery.
Acid Hydrazide: A Potential Reagent for the Synthesis of Semicarbazones
Authors: Yehye Wageeh , Nath Amit
Published: August 2018

Complex semicarbazone derivatives were successfully synthesized from substituted semicarbazides in acidic ethanol upon heating in the presence of aldehyde. The reaction is functional group tolerant and chemoselective because no terminal hydrazine moiety is present in the substituted semicarbazides. Thus, functional groups such as esters and acetyls, which are prone to reaction with hydrazine, can also be used in this reaction because the terminal hydrazine moiety of the acid hydrazide was protected by aryl isocyanates in order to prepare substituted semicarbazides. In addition, neither of the aryl groups of semicarbazone are dependent on the starting materials (acid hydrazide) and can be changed upon demand. Thus, this reaction protocol provides a simple and effective alternative for the preparation of a wide variety of semicarbazones that could not be synthesized by utilizing conventional methods.
Enzalutamida vs abiraterona en el manejo del cáncer de próstata resistente a la castración: comparación indirecta de tratamientos
Authors: Poveda José Luis , Bautista Natalia , Gómez Jorge , Rincón Gilberto , Donoso Wilfredo , González Cesar
Published: August 2018

Introducción Actualmente se dispone de nuevos medicamentos que aumentan la supervivencia en pacientes con cáncer de próstata resistente a la castración. Entre ellos están la Enzalutamida y la Abiraterona. Actualmente no se dispone de experimentos clínicos comparativos. Este estudio tiene como objetivo identificar las diferencias entre la Enzalutamida y la Abiraterona, a través de un modelo de comparación indirecta de tratamientos en pacientes con cáncer de próstata metastásico resistente a la castración.

Materiales y Métodos Se realizó una búsqueda sistemática de la literatura incluyendo ensayos clínicos aleatorizados, en pacientes con cáncer de próstata resistente a la castración que recibieron manejo con Enzalutamida y Abiraterona; tomando como desenlace la supervivencia global y libre de progresión radiológica. Se realizó una comparación de la información y un modelo de Bucher para datos indirectos.

Resultados Se incluyeron 2 experimentos clínicos fase 3 de manejo pre quimioterapia y 2 en manejo postquimioterapia. Se involucraron 1418 pacientes en el grupo de estudio prequimioterapia y 1596 en el grupo de estudio postquimioterapia. Al comparar la Enzalutamida versus Abiraterona, no se encontraron diferencias estadísticamente significativas. En la prequimioterapia, la supervivencia global con HR 0,87 (95%IC 0,70–1,09) (p = 0,94), supervivencia libre de progresion radiológica con HR 0,35 (95% IC 0,28–0,44) (p = 0,81) y en postquimioterapia, supervivencia global con HR 0,85 (95% IC 0,67–1,06) (p = 0,82) y supervivencia libre de progresión radiológica con HR 0,60 (95% IC 0,49–0,74) (p = 0,82).

Conclusiones No existe una diferencia estadísticamente significativa en la supervivencia global y libre de progresión radiológica entre los dos medicamentos.
A Standardized Approach to Cesarean Surgical Technique and Its Effect on Operative Time and Surgical Morbidity
Authors: Pallister M. , Ballas J. , Kohn J. , Eppes C. S. , Belfort M. , Davidson C.
Published: August 2018

Objective To evaluate the impact of a standardized surgical technique for primary cesarean deliveries (CDs) on operative time and surgical morbidity.

Materials and Methods Two-year retrospective chart review of primary CD performed around the implementation of a standardized CD surgical technique. The primary outcome was total operative time (TOT). Secondary outcomes included incision-to-delivery time (ITDT), surgical site infection, blood loss, and maternal and fetal injuries.

Results When comparing pre- versus postimplementation surgical times, there was no significant difference in TOT (76.5 vs. 75.9 minutes, respectively; p = 0.42) or ITDT (9.8 vs. 8.8 minutes, respectively; p = 0.06) when the entire cohort was analyzed. Subgroup analysis of CD performed early versus late in an academic year among the pre- and postimplementation groups showed no significant difference in TOT (79.3 early vs. 73.8 minutes late; p = 0.10) or ITDT (10.8 early vs. 8.8 minutes late; p = 0.06) within the preimplementation group. In the postimplementation group, however, there was significant decrease in TOT (80.5 early vs. 71.3 minutes late; p = 0.02) and ITDT (10.6 early vs. 6.8 minutes late; p < 0.01). Secondary outcomes were similar for both groups.

Conclusion A standardized surgical technique combined with surgical experience can decrease TOT and ITDT in primary CD without increasing maternal morbidity.
Sildenafil Exposure in the Neonatal Intensive Care Unit
Authors: Thompson Elizabeth , Perez Krystle , Smith P. , Clark Reese , Laughon Matthew , Hornik Christoph ,   on behalf of the Best Pharmaceuticals for Children Act—Pediatric Trials Network Steering Committee
Published: August 2018

Objective Pulmonary hypertension causes substantial morbidity and mortality in infants. Although Food and Drug Administration approved to treat pulmonary arterial hypertension in adults, sildenafil is not approved for infants. We sought to describe sildenafil exposure and associated diagnoses and outcomes in infants.

Study Design Retrospective cohort of neonates discharged from more than 300 neonatal intensive care units from 2001 to 2016.

Results Sildenafil was administered to 1,336/1,161,808 infants (0.11%; 1.1 per 1,000 infants); 0/35,977 received sildenafil in 2001 versus 151/90,544 (0.17%; 1.7 per 1,000 infants) in 2016. Among infants <32 weeks' gestational age (GA) with enough data to determine respiratory outcome, 666/704 (95%) had bronchopulmonary dysplasia (BPD). Among infants ≥32 weeks GA, 248/455 (55%) had BPD and 76/552 (14%) were diagnosed with meconium aspiration. Overall, 209/921 (23%) died prior to discharge.

Conclusion The use of sildenafil has increased since 2001. Exposed infants were commonly diagnosed with BPD. Further studies evaluating dosing, safety, and efficacy of sildenafil are needed.
Pleurapunktion – Schritt für Schritt
Authors: Leo Fabian , Makowska Magdalena
Published: August 2018

Pleural effusions of unknown origin and parapneumonic effusions almost invariably require thoracentesis. Fluid analysis is fundamental and guides further diagnostic and therapeutic decisions. Thoracentesis yields high diagnostic value and is a generally safe procedure – given that some basic principles are considered.
Correction: The politics of the China―Pakistan economic corridor
Authors: Hameed Maham
Published: August 2018

The original article did not include an acknowledgements section. This has been corrected in both the HTML and PDF versions of this paper.
Considering transgender and gender nonconforming people in health communication campaigns
Authors: Combs Ryan , Wendel Monica , Gonzales T.
Published: August 2018

Transgender and gender nonconforming (TGNC) people have become more visible and risen in the American public’s consciousness in recent years. Despite this visibility and some political gains such as piecemeal advances in legal gender recognition and nondiscrimination protection, TGNC people continue to experience extensive health and social disparities. Notably, these disparities include a higher human immunodeficiency virus (HIV) burden, poorer mental health outcomes, and barriers to health care. Public health professionals in the United States have called for TGNC health inequities to be addressed and health communication is an important component of this effort. This article begins with an overview of the research evidence about the extent of TGNC disparities and contextualizes them socio-politically. Then, we review a sample of existing health communication campaigns relating to breast, cervical, and testicular cancers through a TGNC lens. Finally, we make a case for considering TGNC people in the development and delivery of health communication campaigns. Recommendations are made for how to do this effectively. Suggested actions include reviewing existing materials for gender inclusivity, engaging communities to determine accurate and relevant messaging, collecting population-level demographic data on gender identity, and training employees using a health equity framework.
Uncertainty analysis of axial temperature and Seebeck coefficient measurements
Authors: Yazdani Sajad , Kim Hyun-Young , Pettes Michael Thompson
Published: August 2018

Experimental investigations of solid materials at elevated temperatures rely on the optimized thermal design of the measurement system, as radiation becomes a predominant source of heat loss which can lead to large uncertainty in measured temperature and related physical properties of a test sample. Advancements in surface temperature measurements have reduced thermal losses arising from the cold-finger effect using axially inserted thermocouples and from radiation using shields or other thermal guards. The leading technology for temperature sensing at temperatures up to ∼900 °C makes use of these design features for measuring thermopower, yet uncertainty analysis estimation of this technique is not known. This work makes use of finite element modeling to determine spatial temperature distributions to obtain the upper limit of confidence expected for the axially inserted thermocouple approach when a heated radiation shield is incorporated into the design. Using an axially inserted thermocouple to measure the sample surface temperature, the temperature variations across the sample hot and cold surfaces at 900 °C for a temperature drop of 0, 5, and 10 °C are calculated to be as low as 0.02, 0.21, and 0.41 °C, respectively, when a heated radiation shield is employed. Uniform temperature distribution on the thermocouple cross-wire geometry indicates that the axial thermocouple measurement design is indeed effective for suppressing the cold-finger effect. Using a heated radiation shield is found to significantly reduce the temperature gradient across the thermocouples.
Wide field of view, real time bioimaging apparatus for noninvasive analysis of nanocarrier pharmacokinetics in living model animals
Authors: Zhang Chao-Jie , Wang Chuan-Xi , Gao Zhi-Yue , Ke Can , Fu Li-Min , Zhang Zhuo , Wang Yuan , Zhang Jian-Ping
Published: August 2018

Understanding nanocarrier pharmacokinetics is crucial for the emerging nanopharmacy, which highly demands noninvasive and real-time visualization of the in vivo dynamics of nanocarriers. To this end, we have developed a 2-photon excitation and time-resolved (TPE-TR) bioimaging apparatus for the analysis of the spatial distribution and temporal evolution of nanocarriers in living model animals. The specific polymeric nanocarrier, Eu@pmma-maa doped with Eu-complexes luminescing in long persistence at ∼615 nm upon near-infrared 2-photon excitation, allows the complete rejection of tissue autofluorescence by selective luminescence detection. This together with a unique beam shaping scheme for homogeneous line excitation, a delicate timing strategy for single-shot line scanning, and an equal optical path design for in-plane scan endows the TPE-TR apparatus with the following prominent features: an imaging depth of ∼10 mm, a field of view (FOV) of 32 × 32 mm2 along with a horizontal resolution of ∼60 μm, a sub-10 s frame time, and negligible laser heating effect. In addition, a combination of the in-plane line scan with the 3D scan of a model animal offers the convenience for examining an interested FOV with a millimeter vertical resolution. Application of TPE-TR bioimaging to a living mouse reveals rich information on the dynamics of nanocarriers including the spatial distribution and temporal evolution and the kinetics of domains of interest. The noninvasive TPE-TR bioimaging instrumentation with a wide FOV and a large imaging depth will find applications in the pharmaceutical development of nanocarriers and relevant research fields.
Self-assembled 2D finned covellite (CuS) for resistive RAM
Authors: Ng Zhen Quan Cavin , Tan Royston Kuan Khoon , Rath Ashutosh , Wee Andrew T. S. , Chua Daniel H. C.
Published: August 2018

Copper sulfides (Cu2−xS) comprises a family of sulfides which possess good electrical and photovoltaic properties due to their self-doping (p-type) nature, attributed from the copper vacancies in their structure. Recently, metal sulfide thin films have been investigated for their resistive RAM behaviour due to the reversible formation of conductive bridges between crystalline structures. In this letter, 2D self-assembled finned covellite (CuS) was prepared via RF Magnetron Sputtering. This 2D finned CuS was found to be polycrystalline via TEM, exhibiting ReRAM behaviour with resistances having two orders of magnitude differences between 0 and −0.5 V. This fin structure eliminates the need for a multi-layered device which until now is the primary method of harnessing the ReRAM behaviour in copper sulphide. It gives rise to very low voltages of −3 V and 1 V for writing and reset, respectively, with a writing time of 20 ms.
Ultrafast and precision drilling of glass by selective absorption of fiber-laser pulse into femtosecond-laser-induced filament
Authors: Ito Yusuke , Yoshizaki Reina , Miyamoto Naoyuki , Sugita Naohiko
Published: August 2018

The extremely intense light emitted from femtosecond laser pulses enables micro-drilling of glass. However, there are problems in femtosecond laser drilling, including low drilling speed and the damage during drilling. Because the volume removed by one femtosecond laser pulse is too small, hundreds of pulses must be focused on a single spot to create a hole with a diameter of 10 μm and a depth of over 100 μm. Furthermore, strong stress waves generated during the processing cause damage around the hole. In our research, we achieved ultrafast and precision drilling by coaxially focusing a single femtosecond laser pulse and a fiber laser pulse, with a wavelength that is transparent to the glass. A hole with a diameter of 10 μm and a depth of 133 μm was created in 40 μs, which indicates that the drilling speed was over 5000 times faster than that of conventional femtosecond laser drilling. By investigating the phenomena occurring after laser irradiation, we demonstrated that ultrafast drilling occurred because the fiber laser pulse was selectively absorbed by a high-aspect-ratio filament induced by the femtosecond laser pulse. Moreover, damage generation was inhibited because the material was thermally removed. The results help expand the range of applications for femtosecond laser processing in industry.
Influence of impurity concentration in Ge sources on electrical properties of Ge/Si hetero-junction tunneling field-effect transistors
Authors: Bae Tae-Eon , Kato Kimihiko , Suzuki Ryota , Nakane Ryosho , Takenaka Mitsuru , Takagi Shinichi
Published: August 2018

We have experimentally demonstrated that there is the optimum B doping concentration in the Ge source in terms of the electric performance of Ge/Si hetero-junction tunneling field-effect transistors (TFETs). The degradation in subthreshold swing (SS) is observed for TFETs with the source B concentration higher than 1 × 1020 cm−3, which can cause the degeneration in Ge. This source concentration dependence can be explained by the depression of the energy filtering effect due to the degeneracy of the Fermi level (EF). This interpretation is supported by the temperature dependence of SS in the Ge/Si TFETs with different source concentrations. Also, a low SS value of 60.6 mV/dec, an Ion value of 82.3 nA/μm, and a large Ion/Ioff ratio of 6.8 × 106 are obtained for the 1.1% tensile strain channel with the optimized B concentration in the Ge source. It is found that the influence of the source EF on the electrical characteristics of TFETs is more pronounced for the strained-Si channel TFETs with smaller Eg.eff.
Identification of low-energy peaks in electron emission spectroscopy of InGaN/GaN light-emitting diodes
Authors: Myers Daniel J. , Gelžinytė Kristina , Ho Wan Ying , Iveland Justin , Martinelli Lucio , Peretti Jacques , Weisbuch Claude , Speck James S.
Published: August 2018

The measurement of the energy distribution of vacuum emitted electrons from InGaN/GaN light-emitting diodes (LEDs) has proven essential in understanding the efficiency loss mechanism known as droop. We report on the measurement and identification of a new low-energy feature in addition to the previously measured three peaks present in the electron emission spectrum from a forward biased LED. Photoemission measurements show that the two low-energy peaks correspond to photoemitted electrons from each of the p-contact metals, palladium and gold. We confirm that the mid and high-energy peaks are due to electrons which have transited the p-type region of the device and have been emitted from the semiconductor surface from the bulk Γ-valley or a high-energy side valley.
Effects of RbF postdeposition treatment and heat-light soaking on the metastable acceptor activation of CuInSe2 thin film photovoltaic devices
Authors: Ishizuka Shogo , Shibata Hajime , Nishinaga Jiro , Kamikawa Yukiko , Fons Paul J.
Published: August 2018

Granular particles formed on a CuInSe2 (CIS) thin film surface with alkali-halide RbF post-deposition treatment (RbF-PDT) are found to concentrate preferably on other than smooth (112)-planes present on the CIS film surface. As a consequence, a large number of distinctive pores are selectively formed at relatively rough facets. Although the open circuit voltage and fill factor values of CIS solar cells improve with either RbF-PDT or heat-light soaking (HLS) treatment, the effects of these treatments are distinguishable. The ratio of carrier recombination rates at the interface (Ri) to that in the bulk (Rb), namely, Ri/Rb, decreases with RbF-PDT. HLS treatment performed on RbF-PDT CIS devices leads to a further decrease in the value of Ri/Rb, whereas the value of Ri/Rb of CIS devices fabricated without RbF-PDT increases with HLS treatment. Ternary CIS solar cells grown with RbF-PDT and HLS treatment reproducibly demonstrate enhanced photovoltaic efficiencies.
Interactions between silver inner electrode and Fe-Si-Cr alloy of metal multilayer chip inductors
Authors: Wu Yung-Ping , Chiang Hsin-Yun , Hsiang Hsing-I
Published: August 2018

The silver diffusion and chemical reaction between Fe-Si-Cr alloy and Ag during multilayer metal power inductor preparation are investigated using scanning electron microscopy, field emission transmission electron microscopy and multipurpose X-Ray thin-film diffractometer. The experimental results show that a large amount of inner electrode, Ag, volatilize and diffuse under air atmosphere during co-firing, resulting in the reaction between Ag and thermally grown oxide layer, Cr2O3, forming flaky AgCrO2. The p-type semiconductor, AgCrO2 will cause the insulation degradation of the co-fired Fe-Si-Cr alloy multilayer chip inductors, hence reducing the power conversion efficiency due to the increase in eddy current loss.
Fast synthetic X-mode Doppler reflectometry diagnostics for the full-f global gyrokinetic modeling of the FT-2 tokamak
Authors: Altukhov A. B. , Gurchenko A. D. , Gusakov E. Z. , Irzak M. A. , Niskala P. , Esipov L. A. , Kiviniemi T. P. , Leerink S.
Published: August 2018

The fast linear (Born approximation) version of the X-mode Doppler reflectometry (DR) synthetic diagnostics is developed in the framework of the ELMFIRE global gyrokinetic modeling of the FT-2 tokamak ohmic discharge. The DR signal frequency spectra and the dependence of their frequency shift and shape on the probing antenna position are computed and shown to be similar to those measured in the high magnetic field side probing DR experiment at the FT-2 tokamak. The fluctuation poloidal velocities are determined using the DR experiment and synthetic diagnostics and shown to be within 15%. However, the computed and measured dependences of the DR signal power on the antenna position appear to be different presumably due to underestimation of the small-scale trapped electron mode turbulence component in the measurement region by the code.
Note: Investigation of a Marx generator imitating a Tesla transformer
Authors: McGuyer B. H.
Published: August 2018

A compact Marx generator was built to mimic a spark-gap Tesla transformer. The generator produced radio-frequency pulses of up to ±200 kV and ±15 A with a frequency between 110 and 280 kHz at a repetition rate of 120 Hz. The generator tolerated larger circuit-parameter perturbations than is expected for conventional Tesla transformers. Possible applications include research on the control and laser guiding of spark discharges.
Influence of the laser plasma-expansion specific on a cathode jet formation and the current stability in a laser-ignited vacuum discharge
Authors: Romanov I. V. , Tsygvintsev I. P. , Paperny V. L. , Kologrivov A. A. , Korobkin Yu. V. , Krukovskiy A. Yu. , Rupasov A. A.
Published: August 2018

The formation of a current-plasma shell is studied during the expansion of a laser-ignited low-power vacuum-discharge cathode plasma jet into the interelectrode gap. The shell geometry is found to be determined by the mode of laser-plasma expansion at the discharge ignition stage. It is shown that the increase in the laser-beam focal spot area on the cathode surface leads to the increase in the matter density and the decrease in the density gradient in the discharge gap and to transition from the spherical laser-plasma expansion mode to the jet mode. The latter considerably stabilizes the current transfer in the discharge plasma, even during the development of the hydrodynamic sausage instability in it.
Mode specific dynamics in bond selective reaction O′(3P) + HOD → O′H + OD/O′D + OH
Authors: Zheng Rui , Zhu Yongfa , Song Hongwei
Published: August 2018

Taking advantage of bond selectivity and mode specificity has long been realized to control the outcome of chemical reactions. The mode-specific dynamics in the bond selective abstraction reaction O′(3P) + HOD are investigated using a full-dimensional time-dependent quantum wave packet method. Integral cross sections and product branching ratios from several low-lying vibrational states of the reactant HOD are calculated on an accurate global potential energy surface describing the lowest triplet state of the HOOH system. Both the H-abstraction reaction and the D-abstraction reaction prefer the vibrational energy to the translational energy, satisfying the prediction of Polanyi rules for a late-barrier reaction. The observed strong bond selectivity can be rationalized by the sudden vector projection model as well. The bias to the D-abstraction channel for the reaction O′(3P) + HOD from the reactant ground state can be partially attributed to the different mass combination in comparison to the H + HOD reaction, in which the H-abstraction channel is more favored.
Calculation of large-aspect-ratio tokamak and toroidally-averaged stellarator equilibria of high-beta reduced magnetohydrodynamics via simulated annealing
Authors: Furukawa M. , Watanabe Takahiro , Morrison P. J. , Ichiguchi K.
Published: August 2018

A simulated annealing (SA) relaxation method is used for the calculation of high-beta reduced magnetohydrodynamics (MHD) equilibria in toroidal geometry. The SA method, based on artificial dynamics derived from the MHD Hamiltonian structure, is used to calculate equilibria of large-aspect-ratio and circular-cross-section tokamaks as well as toroidally averaged stellarators. Tokamak equilibria including incompressible poloidal rotations are obtained and the Shafranov shift is seen to increase nearly quadratically in the rotation speed. A mapping procedure between non-rotating and poloidally rotating equilibria is shown to explain the quadratic dependence of equilibria shift on rotation. Calculated stellarator equilibria are seen to agree reasonably with previous results. The numerical results demonstrate the first successful application of the SA method to obtain toroidal equilibria.
Observation and evaluation of the alignment of Thomson scattering systems
Authors: Sos M. , Bohm P. , Grover O. , Bilkova P. , Peterka M. , Weinzettl V. , Hron M. , Panek R.
Published: August 2018

Concerning plasma diagnostics based on Thomson scattering (TS), precise adjustment and proper alignment is of great importance in order to provide reliable and accurate measurements. Any misalignment could result in an incorrectly determined plasma density or prevent the measurement with this type of diagnostic altogether. Suitable means of alignment monitoring should be integrated into each TS diagnostic system. Variations of commonly used methods are discussed in this article. Correlation of results from alignment control with performed measurements of vibrations on the COMPASS tokamak is presented. Various techniques of optimization of alignment monitoring are shown. The optimal technique, which could be accommodated during the construction of TS diagnostic systems in future fusion devices, is proposed.
Apparatus for combined nanoscale gravimetric, stress, and thermal measurements
Authors: Murray Joseph B. , Palm Kevin J. , Narayan Tarun C. , Fork David K. , Sadat Seid , Munday Jeremy N.
Published: August 2018

We present an apparatus that allows for the simultaneous measurement of mass change, heat evolution, and stress of thin film samples deposited on quartz crystal microbalances (QCMs). We show device operation at 24.85 ± 0.05 °C under 9.31 ± 0.02 bars of H2 as a reactive gas. Using a 335 nm palladium film, we demonstrate that our apparatus quantifies curvature changes of 0.001 m−1. Using the QCM curvature to account for stress induced frequency changes, we demonstrate the measurement of mass changes of 13 ng/cm2 in material systems exhibiting large stress fluctuations. We use a one-state nonlinear lumped element model to describe our system with thermal potentials measured at discrete positions by three resistance temperature devices lithographically printed on the QCM. By inputting known heat amounts through lithographically defined Cr/Al wires, we demonstrate a 150 μW calorimetric accuracy and 20 μW minimum detectable power. The capabilities of this instrument will allow for a more complete characterization of reactions occurring in nanoscale systems, such as the effects of hydrogenation in various metal films and nanostructures, as well as allow for direct stress compensation in QCM measurements.
Enhanced photoluminescence properties of SrTiO3:Pr3+ nanocrystals by the “TEG-sol” method
Authors: Zhang Jiameng , Hao Yanan , Wang Qingmin , Xu Jianchun , Guo Limin , Bi Ke
Published: August 2018

SrTiO3(STO):Pr3+ nanopowders are synthesized because of their excellent photoluminescence (PL) performance. The PL intensity is enhanced by morphological control and oxygen vacancy. The “TEG-sol” method is used to prepare STO:Pr3+ nanopowders with a size lower than 10 nm. Abundant oxygen vacancies are formed in the nanopowders without any further processing. The effect of annealing temperature on the PL properties is systematically studied. Bright green-white emission is achieved from pristine STO:Pr3+. Red emission is obtained after annealing at a temperature higher than 400 °C. A flexible and translucent STO:Pr3+/polyvinylidene fluoride nanocomposite film is fabricated, which shows outstanding PL and dielectric properties.
Transition from homogeneous stationary to oscillating state in planar gas discharge–semiconductor system in nitrogen: Effect of fluid modelling approach
Authors: Rafatov Ismail , Yesil Cihan
Published: August 2018

A laterally extended dc-driven system of planar gas discharge with a high-ohmic semiconductor electrode is considered. Numerical models are based on the fluid equations of plasma with drift-diffusion approximation for particle fluxes. The effect of different modelling approaches (with simpler and more detailed treatment of the electron transport and plasma chemical reactions) is analyzed. Bifurcation diagrams separating stable stationary states of the system from oscillatory states are derived and compared with the experimental data.
Thermocapillary instability of self-rewetting films on vertical fibers
Authors: Yu Z.
Published: August 2018

The self-rewetting fluid has a quadratic temperature dependence of surface tension with a well-defined minimum, which is distinct from that of normal fluids whose surface tension decreases linearly with temperature. The instability of a self-rewetting film on a vertical hot or cold fiber is investigated using the long-wave asymptotic model, which discovers that the role of the thermocapillarity varies in three different regimes. In the normal regime, the behavior of this fluid is similar to that of a normal fluid while in another anomalous regime, it shows a reverse feature of instability. It is this reverse behavior that guarantees the potentials of this fluid in heat transfer applications. Transient numerical simulations are also performed to be compared with the linear theory and to explore the saturate states as well as the breakup for this special fluid. Apart from supporting the conclusions obtained in the linear analysis, noticeably, the numerical results predict a flatter saturate shape and a weaker breakup in the anomalous regime.
A high level of outcrossing in the vulnerable species Prosopis rubriflora in a Chaco remnant
Authors: Alves Fábio M. , Sartori Ângela L. B. , Zucchi Maria I. , Azevedo-Tozzi Ana M. G. , Tambarussi Evandro V. , de Souza Anete P.
Published: August 2018

Prosopis rubriflora Hassl. is a tree species typically found in chaquenian areas, mainly with an arborised phytophysiognomy in the southern region of the Pantanal wetland. This species has become vulnerable in recent decades as a result of considerable increases in anthropogenic activities such as cattle breeding, and this vulnerability has also been observed in several other native species. The goal of this study was to estimate the mating system of P. rubriflora in a Chaco remnant by analysing 10 microsatellite markers. Samples were collected over 2 years (2010–213 seedlings and 2011–180 seedlings), and the results suggest that the mating system of P. rubriflora is preferably allogamous. A progeny array was predominantly composed of half-sibs (from 76 to 79%), full-sibs (from 15%) and self-half-sibs (from 6 to 9%). The outcrossing rate between related individuals was significant in 2011 but not in 2010. The average co-ancestry coefficient () ranged from 0.158 to 0.162, and the variance effective size (Ne) ranged from 3.05 to 3.13. The number of seed trees required for seed collection (m) to retain an effective size of 150 in progeny array samples was 48–49. The high levels of outcrossing of P. rubriflora appear to be related to several mechanisms that avoid selfing and due to the behaviour of native pollinators, which clearly contribute to the gene flow of the species.
Interface dynamics: Mechanisms of stabilization and destabilization and structure of flow fields
Authors: Abarzhi Snezhana I. , Ilyin Daniil V. , Goddard William A. , Anisimov Sergei I.
Published: August 2018

Interfacial mixing and transport are nonequilibrium processes coupling kinetic to macroscopic scales. They occur in fluids, plasmas, and materials over celestial events to atoms. Grasping their fundamentals can advance a broad range of disciplines in science, mathematics, and engineering. This paper focuses on the long-standing classic problem of stability of a phase boundary—a fluid interface that has a mass flow across it. We briefly review the recent advances in theoretical and experimental studies, develop the general theoretical framework directly linking the microscopic interfacial transport to the macroscopic flow fields, discover mechanisms of interface stabilization and destabilization that have not been discussed before for both inertial and accelerated dynamics, and chart perspectives for future research.
Macrophage angiotensin II type 2 receptor triggers neuropathic pain
Authors: Shepherd Andrew J. , Mickle Aaron D. , Golden Judith P. , Mack Madison R. , Halabi Carmen M. , de Kloet Annette D. , Samineni Vijay K. , Kim Brian S. , Krause Eric G. , Gereau Robert W. , Mohapatra Durga P.
Published: August 2018

Significance

Neuropathic pain is a widespread problem that is undermanaged by currently available analgesic drugs. An antagonist of the type II angiotensin II receptor (AT2R) reduces pain behaviors related to neuropathy, suggesting that angiotensin receptor signaling is involved in this pain. We find that AT2R expression is detected not in sensory neurons themselves, but in macrophages that infiltrate the site of nerve injury. Inducible depletion of peripheral macrophages attenuates mechanical and cold pain hypersensitivity related to neuropathy, as does transplantation of AT2R-null bone marrow into an otherwise WT recipient. Our observations provide powerful evidence that neuropathic pain is dependent upon angiotensin signaling, macrophages, and the AT2R-mediated downstream signaling therein.
Collapse of a desert bird community over the past century driven by climate change
Authors: Iknayan Kelly J. , Beissinger Steven R.
Published: August 2018

Significance

Deserts, already defined by climatic extremes, have warmed and dried more than other regions in the contiguous United States due to climate change. Our resurveys of sites originally visited in the early 20th century found Mojave Desert birds strongly declined in occupancy and sites lost nearly half of their species. Declines were associated with climate change, particularly decreased precipitation. The magnitude of the decline in the avian community and the absence of species that were local climatological “winners” are exceptional. Our results provide evidence that bird communities in the Mojave Desert have collapsed to a new, lower baseline. Declines could accelerate with future climate change, as this region is predicted to become drier and hotter by the end of the century.
Genotype-targeted local therapy of glioma
Authors: Shankar Ganesh M. , Kirtane Ameya R. , Miller Julie J. , Mazdiyasni Hormoz , Rogner Jaimie , Tai Tammy , Williams Erik A. , Higuchi Fumi , Juratli Tareq A. , Tateishi Kensuke , Koerner Mara V. A. , Tummala Shilpa S. , Fink Alexandria L. , Penson Tristan , Schmidt Stephen P. , Wojtkiewicz Gregory R. , Baig Aymen , Francis Joshua M. , Rinne Mikael L. , Batten Julie M. , Batchelor Tracy T. , Brastianos Priscilla K. , Curry William T. , Barker Fred G. , Jordan Justin T. , Iafrate A. John , Chi Andrew S. , Lennerz Jochen K. , Meyerson Matthew , Langer Robert , Wakimoto Hiroaki , Traverso Giovanni , Cahill Daniel P.
Published: August 2018

Significance

Lower-grade gliomas are often characterized by mutations in metabolism-related genes isocitrate dehydrogenase 1 (
IDH1
) and
IDH2
. Resection of these tumors is constrained by adjacent eloquent cortex, resulting in local failures. Studies showed that IDH mutant cells are sensitive to metabolic therapeutics, but these drugs are limited by systemic toxicities. We hypothesized that application of metabolism-altering therapeutics at the surgical margin would improve tumor control and minimize toxicity. We developed an intraoperative diagnostic assay to identify IDH mutations. We show that intratumoral administration of sustained release formulations of metabolism-altering compound prolongs survival in a mouse model of IDH mutant glioma. This genotype-based paradigm introduces a workflow in surgical oncology that can be extended to other tumors characterized by targetable molecular alterations.
Declines in methane uptake in forest soils
Authors: Ni Xiangyin , Groffman Peter M.
Published: August 2018

Significance

Atmospheric methane (CH
4
) concentration has been increasing rapidly over recent decades. Forest soils are a major sink for atmospheric CH
4
, but evidence from long-term in situ observation is limited, so little is known about how the soil CH
4
sink responds to changing environmental conditions. We measured soil to atmosphere net CH
4
fluxes at long-term ecological research sites in Baltimore, Maryland (1998–2016) and Hubbard Brook, New Hampshire (2002–2015) and found significant decreases in CH
4
uptake at both sites. Moreover, a literature review showed that CH
4
uptake in forest soils around the world is also declining, especially forests from 0–60 °N latitude, where precipitation has been increasing. We conclude that the current soil CH
4
sink may be overestimated over large regional areas.
Lariat intronic RNAs in the cytoplasm of vertebrate cells
Authors: Talhouarne Gaëlle J. S. , Gall Joseph G.
Published: August 2018

Significance

Introns are noncoding DNA sequences interspersed among the coding sequences of genes. Shortly after transcription, the intronic sequences are spliced out of the primary RNA transcript as lariat RNAs (circular molecules with a short tail). Most of these lariats are destroyed within minutes in the cell nucleus. We report here that many such intronic RNAs are, in fact, exported to the cytoplasm, where they remain as stable circular molecules. These cytoplasmic introns are derived from hundreds of different genes of widely different functions. We find them in cells of human, mouse, chicken, frog, and zebrafish. The widespread occurrence of so many stable lariat RNAs in the cytoplasm suggests that they play some as-yet unexpected role in cell metabolism.
Codon usage influences fitness through RNA toxicity
Authors: Mittal Pragya , Brindle James , Stephen Julie , Plotkin Joshua B. , Kudla Grzegorz
Published: August 2018

Significance

Synonymous mutations in genes do not change protein sequence, but they may affect gene expression and cellular function. Here we describe an unexpected toxic effect of synonymous mutations in
Escherichia coli
, with potentially large implications for bacterial physiology and evolution. Unlike previously studied effects of synonymous mutations, the effect that we discovered is independent of translation, but it depends on the production of toxic mRNA molecules. We hypothesize that the mechanism we identified influences the evolution of endogenous genes in bacteria by imposing selective constraints on synonymous mutations that arise in the genome. Of interest for biotechnology and synthetic biology, we identify bacterial strains and growth conditions that alleviate RNA toxicity, thus allowing efficient overexpression of heterologous proteins.
Trajectories of the Earth System in the Anthropocene
Authors: Steffen Will , Rockström Johan , Richardson Katherine , Lenton Timothy M. , Folke Carl , Liverman Diana , Summerhayes Colin P. , Barnosky Anthony D. , Cornell Sarah E. , Crucifix Michel , Donges Jonathan F. , Fetzer Ingo , Lade Steven J. , Scheffer Marten , Winkelmann Ricarda , Schellnhuber Hans Joachim
Published: August 2018

We explore the risk that self-reinforcing feedbacks could push the Earth System toward a planetary threshold that, if crossed, could prevent stabilization of the climate at intermediate temperature rises and cause continued warming on a “Hothouse Earth” pathway even as human emissions are reduced. Crossing the threshold would lead to a much higher global average temperature than any interglacial in the past 1.2 million years and to sea levels significantly higher than at any time in the Holocene. We examine the evidence that such a threshold might exist and where it might be. If the threshold is crossed, the resulting trajectory would likely cause serious disruptions to ecosystems, society, and economies. Collective human action is required to steer the Earth System away from a potential threshold and stabilize it in a habitable interglacial-like state. Such action entails stewardship of the entire Earth System—biosphere, climate, and societies—and could include decarbonization of the global economy, enhancement of biosphere carbon sinks, behavioral changes, technological innovations, new governance arrangements, and transformed social values.