bluuebunny/crossref_metadata_2025 huggingface dataset:
Amputationen der unteren Extremität in Deutschland – Regionale Analyse mit Krankenhausabrechnungsdaten von 2011 bis 2015
Authors: Spoden Melissa
Published: March 2019

Ziel der Arbeit Amputationen vermindern irreversibel die Lebensqualität. Das Ziel vorangehender Versorgung ist stets eine Amputation zu verhindern. Diese Versorgung sollte bundesweit mit derselben Ergebnisqualität gewährleistet sein. Ziel dieser Arbeit ist es, regionale Versorgungsunterschiede sichtbar zu machen, indem Amputationsfallzahlen nach Amputationshöhen auf Kreisebene analysiert werden.

Methodik In den deutschlandweiten Krankenhausabrechnungsdaten (DRG-Statistik) wurden alle Behandlungsfälle mit Amputation an der unteren Extremität zwischen 2011 und 2015 identifiziert. Auf Kreisebene wurden rohe Raten sowie alters- und geschlechtsstandardisierte Raten pro 100 000 Einwohner dargestellt. Daneben wurde die systematische Variationskomponente (SCV) zwischen den Kreisen betrachtet und das standardisierte Morbiditätsverhältnis (SMR) in Funnel Plots dargestellt.

Ergebnisse Im Beobachtungszeitraum belief sich die mediane jährliche Amputationsrate auf 67 Fälle pro 100 000 Einwohner. Auf Kreisebene variierte die rohe Rate um das 6-fache. Unabhängig von demografischen Unterschieden zeigten sich Variationen zwischen den Kreisen. Erhöhte Amputationsraten wurden überwiegend im Osten und Südosten beobachtet. Die Variationen waren bei den Amputationshöhen Zeh/Zehenstrahl (SCV 11,8) und Fuß komplett & Mittel-/Vorfuß (SCV 11,7) am stärksten ausgeprägt.

Schlussfolgerung Es bestehen deutliche regionale Unterschiede in den Amputationsraten. Bei peripheren Amputationshöhen ist die systematische Variation am stärksten. Insbesondere im Osten und Südosten sind regionale Cluster erkennbar, die Anhaltspunkte für einen möglichen regionalen Verbesserungsbedarf in der Versorgung liefern.
Lymphatic micrometastases predict biochemical recurrence in patients undergoing radical prostatectomy and pelvic lymph node dissection for prostate cancer
Authors: Maxeiner Andreas , Grevendieck Andreas , Pross Therese , Rudl Marc , Arnold Alexander , Stephan Carsten , Jung Klaus , Miller Kurt , Kilic Ergin , Busch Jonas
Published: March 2019

Background Nodal metastasis is a strong prognostic parameter in prostate cancer (PCa). We analysed the detection of micrometastases (miN + ) in initially nodal-negative (pN0) radical prostatectomy specimens from pT2a-c and pT3a PCa patients by immunohistochemistry (IHC).

Material and Methods A total of 2352 lymph nodes of 193 PCa patients were centrally re-examined for miN + or miN- status using IHC. Results were correlated with clinical and follow-up data. Recurrence-free survival (RFS) was calculated with the log-rank test using the Kaplan-Meier method. In addition, a logistic regression analysis was performed.

Results IHC detected miN + in a total of 17 patients (8.8 %). miN + seemed to be significantly associated with a higher Gleason score and was detected in more advanced pT stages. A total of 45 patients (23.1 %) had a biochemical recurrence (BCR). BCR was associated with miN +. Patients with miN + had a significantly shorter RFS (22.9 versus 58.7 months; p < 0.001). In the univariate (OR: 5.04; 95 % CI: 2.46 – 10.6; p-value: < 0.0001) and multivariate (OR: 3.29; 95 % CI: 1.54 – 7.08; p-value: 0.002) regression model, the miN + status was the strongest predictor of a BCR.

Conclusions IHC seems to be of high diagnostic value for the detection of micrometastases in initially nodal-negative PCa patients. IHC should therefore be performed in PCa patients with nodal-negative findings.
Regioselective Synthesis of 5-(Trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidines from β-Enamino Diketones
Authors: Andrade Valquiria , Mittersteiner Mateus , Bonacorso Helio , Frizzo Clarissa , Martins Marcos , Zanatta Nilo
Published: March 2019

The use of β-enamino diketones as an easy entry to the regioselective synthesis of [1,2,4]triazolo[1,5-a]pyrimidines is reported. These ketones reacted with 3-amino-1H-1,2,4-triazoles to furnish exclusively 6-substituted 5-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidines in yields of up to 95%. The regioselectivity of the reactions performed was maintained regardless of the substituent in the starting ketone or aminoazole.
Surgical Management of Deep-Seated Metastatic Brain Tumors Using Minimally Invasive Approaches
Authors: Gassie Kelly , Alvarado-Estrada Keila , Bechtle Perry , Chaichana Kaisorn
Published: March 2019

Background and Study Aims/Objective Metastatic brain tumors are the most common type of adult brain tumors. Treatment involves surgery and/or radiation therapy. Surgery is typically reserved for patients with good neurologic function, solitary and accessible lesions, symptomatic lesions, and/or those with good systemic control of their primary cancer. Deep-seated lesions, however, are typically treated with palliative options including radiation and medical therapies. We summarize our personal experience with minimally invasive surgical approaches for these deep-seated metastatic brain tumors using tubular retractors with exoscopic visualization.

Material and Methods Patients with deep-seated metastatic brain tumors who were operated on from January 2016 to December 2017 by the senior author were collected prospectively. “Deep seated” was defined as any subcortical location below the deepest adjacent sulcus in close proximity to the basal ganglia and/or thalamus. “Minimally invasive” was defined as the use of tubular retractors with exoscopic visualization.

Results A total of 15 consecutive patients with an average ± standard deviation age of 63 ± 12 years underwent surgical resection of a deep-seated metastasis. The tumor was located in the centrum semiovale in seven (47%) (3 corticospinal tract, 2 superior longitudinal fasciculus, 1 visual tract, 1 inferior frontal occipital fasciculus), basal ganglia in three (20%), thalamus in two (13%), and cerebellum in three (20%). Median percentage resection was 100% (interquartile range:100–100%), and, following surgery, seven (47%), seven (47%), and one (7%) had an improved, stable, and worse Karnofsky Performance Score, respectively. No patients had notable local complications including stroke, infection, hemorrhage, and/or seizure. All patients underwent postoperative stereotactic radiosurgery.

Conclusion This minimally invasive approach can be used to achieve extensive resection with minimal morbidity for arguably the highest risk metastatic brain tumors.
Alcohol Consumption and Risk of First-Time Venous Thromboembolism in Men and Women
Authors: Johansson Magdalena , Johansson Lars , Wennberg Maria , Lind Marcus
Published: March 2019

Background The relationship between alcohol intake and risk of venous thromboembolism (VTE) is unclear. Men and women differ in their drinking habits, which may affect a possible association.

Objective This article investigates the association between alcohol consumption, alcohol dependence and VTE in the total population as well as in men and women separately.

Methods We performed a prospective, population-based cohort study in northern Sweden. Study participants were 108,025 (51% women) persons aged 30 to 60 years who underwent a health examination between 1985 and 2014. We assessed alcohol consumption and defined alcohol dependence using a questionnaire. The outcome was a validated first-time VTE.

Results The mean follow-up time was 13.9 years, and 2,054 participants had a first-time VTE. The mean alcohol consumption was 3.5 standard drinks weekly in men and 1.5 in women. Alcohol dependence was found in 10% of men and 3% of women. There was an association between alcohol consumption (hazard ratio [HR], 1.02; 95% confidence interval [CI], 1.00–1.03 per standard drink weekly) as well as alcohol dependence (HR, 1.27; 95% CI, 1.06–1.52) and VTE after adjustments. In men, the risk of VTE increased over quartiles of weekly alcohol consumption (p for trend 0.02), with a HR of 1.22 (95% CI, 1.01–1.47) for the highest quartile. Alcohol dependence was associated with VTE in men (HR, 1.30; 95% CI, 1.07–1.59). In women, there were no significant associations.

Conclusion High alcohol consumption and alcohol dependence were associated with increased risk of first-time VTE in men, but not in women.
Effect of Diabetes on the Male Reproductive System—A Histomorphological Study
Authors: Kotian Sushma , Kumar Ashok , Mallik Sanchari , Bhat Nandini , Souza Anne , Pandey Arvind
Published: March 2019

Introduction Type 1 diabetes is an autoimmune disorder characterized by lack of insulin production by the β cells of the pancreas. This lack of insulin causes a variety of systemic effects on the metabolism of the body, one of which is reproductive dysfunction. The present study investigates the effects of diabetes on the male reproductive system of streptozotocin (STZ)-induced diabetic rats.

Material and Methods A total of 18 adult male Wistar rats weighing ∼ between 250 and 300 g were included in the present study. The animals were divided into normal and diabetic groups. The diabetic group was further subdivided into 2 subgroups with durations of 24 and 48 days. A single dose of STZ (40 mg/kg body weight) was administrated intraperitoneally to the animals of the diabetic group. After the planned duration, the testes and epididymides were dissected, and their gross weight was measured. The tissues were then processed for histological study.

Results The gross weight of the testes and epididymides in diabetic rats at 24 and 48 days showed a decrease in comparison to the control. (p < 0.01 for testes and epididymides).

Diabetic animals presented a significant decrease in the diameter of the seminiferous tubules compared with the control group (p < 0.01). The epididymides in the diabetic groups showed a considerable reduction in the tubular surface area compared with the control group (p < 0.01). There was also a reduction in the mean diameter, which was measured using the maximum and minimum diameter of the tubules (p < 0.01).

Conclusion The present study is an insight into the adverse effects that diabetes can have on the tissue structure of the testes, of the epididymides, and ultimately on the process of spermatogenesis.
Participation of the Intercostal Nerves to the Innervation of the Diaphragm Muscle in Cavia porcellus
Authors: de Faria Marcelo , Gradela Adriana , Santos Ana , Lopes Ítalo , Inoue Vanessa , Brito Bárbara
Published: March 2019

Introduction The diaphragm is the leading respiratory muscle. It is innervated mainly by the diaphragmatic nerve, and, in some species, by the delicate fibers of the intercostal nerves. In guinea pigs, there is no description of these anatomic structures that innerve this important muscle. This study aimed to analyze the participation of the intercostal nerves to the innervations of the diaphragm of guinea pigs of both sexes.

Materials and Methods We studied 40 guinea pigs (Cavia porcellus) of both sexes. We fixed and dissected the diaphragm of the specimens used in the experiment to assess the path of the intercostals nerves in both the body antimeres.

Results The diaphragm was innervated by the intercostal nerve pairs 6 through 12, and, less frequently, by the 8th nerve (38/40 = 95%), followed by the 7th (36/40 = 90%) and subsequently by the 9th (32/40 = 80%). The 12th nerve presented the lowest frequency (2/20 = 10%) in both genders. All nerve pairs displayed similar occurrence compared with the gender and the antimeric disposition. The only exception was the 9th nerve, which presented a significant variation of the occurrence, both in relation to gender and antimeric disposition. From a statistic point of view, all nerves were independent. We observed no correlation between the gender and their position.

Conclusions We shall conclude that the diaphragm of guinea pigs is innervated by the 6th through 12th pairs of intercostal nerves, with the 7th, 8th, and 9th being the primary providers. There is no interference of the variables gender or antimeric disposition on the behavior of the intercostal nerves of guinea pigs as refers to their origin and participation to the innervations of the diaphragm.
I
-preserving diffeomorphisms of Lorentzian manifolds
Authors: McNutt David Duncan , Aadne Matthew Terje
Published: March 2019

We examine the existence of one parameter group of diffeomorphisms whose infinitesimal generators annihilate all scalar polynomial curvature invariants through the application of the Lie derivative, known as I-preserving diffeomorphisms. Such mappings are a generalization of isometries and appear to be related to nil-Killing vector fields, for which the associated Lie derivative of the metric yields a nilpotent rank two tensor. We show that the set of nil-Killing vector fields contains Lie algebras, although the Lie algebras may be infinite and can contain elements which are not I-preserving diffeomorphisms. We then study the curvature structure of a general Lorenztian manifold, or spacetime to show that I-preserving diffeomorphism will only exist for the I-degenerate spacetimes and to determine when the I-preserving diffeomorphisms are generated by nil-Killing vector fields. We identify necessary and sufficient conditions for the degenerate Kundt spacetimes to admit an additional I-preserving diffeomorphism and conclude with an application to the class of Kundt spacetimes with constant scalar polynomial curvature invariants to show that a finite transitive Lie algebra of nil-Killing vector fields always exists for these spacetimes.
Combining multiple forecasts for multivariate time series via state-dependent weighting
Authors: Okuno Shunya , Aihara Kazuyuki , Hirata Yoshito
Published: March 2019

We present a model-free forecast algorithm that dynamically combines multiple forecasts using multivariate time series data. The underlying principle is based on the fact that forecast performance depends on the position in the state space. This property is exploited to weight multiple forecasts via a local loss function. Specifically, additional weights are assigned to appropriate forecasts depending on their positions in a state space reconstructed via delay coordinates. The function evaluates the forecast error discounted by the distance in the space, whereas most existing methods discount the error in relation to time. In addition, forecasts are selected with the function for each time step based on the existing multiview embedding approach; by contrast, the original multiview embedding selects the reconstructions in advance before starting the forecast. The proposed prediction method has the smallest mean squared error among conventional ensemble methods for the Rössler and the Lorenz'96I models. The results of comparison of the proposed method with conventional machine-learning methods using a flood forecast example indicate that the proposed method yields superior accuracy. We also demonstrate that the proposed method might even correctly forecast the maximum water level of rivers without any prior knowledge.
Heterodyne transient vibrational SFG to reveal molecular responses to interfacial charge transfer
Authors: Li Yingmin , Xiang Bo , Xiong Wei
Published: March 2019

We demonstrate heterodyne detected transient vibrational sum frequency generation (VSFG) spectroscopy and use it to probe transient electric fields caused by interfacial charge transfer at organic semiconductor and metal interfaces. The static and transient VSFG spectra are composed of both non-resonant and molecular resonant responses. To further disentangle both contributions, we apply phase rotation to make the imaginary part of the spectra be purely molecular responses and the real part of the spectra be dominated by non-resonant signals. By separating non-resonant and molecular signals, we can track their responses to the transient electric-fields at interfaces independently. This technique combined with the phase sensitivity gained by heterodyne detection allows us to successfully identify three types of photoinduced dynamics at organic semiconductor/metal interfaces: coherent artifacts, optical excitations that do not lead to charge transfer, and direct charge transfers. The ability to separately follow the influence of built-in electric fields to interfacial molecules, regardless of strong non-resonant signals, will enable tracking of ultrafast charge dynamics with molecular specificities on molecular optoelectronics, photovoltaics, and solar materials.
Strain engineering in functional materials
Authors: Tsutsui G. , Mochizuki S. , Loubet N. , Bedell S. W. , Sadana D. K.
Published: March 2019

Silicon based complementary metal-oxide-semiconductor field-effect-transistor (CMOSFET) technology has continued to progress unabated for last five decades despite various challenges arising due to extreme scaling. Pervasive use of Si technology is evident in a large spectrum of products ranging from high end mainframe and server computers for businesses to laptops, smartphones, and internet of things (IoT) for consumer-oriented products. There is an ever-increasing demand to improve Si device performance for the above described and future products. Strain engineering is one of the key aspects to improve transistor performance. In this review, we describe strain engineering in silicon based advanced CMOS technology, which has evolved from conventional two-dimensional (2D) MOSFET structure to 3D FinFET structure. The impact of shrinking dimensions of scaled FinFETs on channel strain engineering as well as options for strain engineering in future CMOS architecture are described. Finally, strain engineering in non-silicon based functional materials such as gallium nitride (GaN) and 2D materials will be briefly discussed.
Refinement of synthetic guanine crystals for fast diamagnetic rotation
Authors: Mootha Archana , Suzuki Kentaro , Kimura Takayuki , Kurahashi Masaru , Muneyama Etsuhiro , Iwasaka Masakazu , Asada Hironori
Published: March 2019

Synthetic guanine crystals, with the same magnetic controllable reflection property as a biogenic guanine crystal from fish scales, were prepared using a classical Ostwald ripening method for crude crystals, from the aqueous sodium hydroxide solution of a commercially available synthesized guanine powder. The resulting synthetic guanine crystals with an average size of several tens of micrometers were in the same crystal system as the biogenic guanine crystals under measurement by X-ray diffraction (XRD). However, XRD patterns of water-floating crystals showed that the correlation between the growing direction and reflecting surface in the synthetic crystals is different from that in the biogenic crystals. Therefore, the synthetic crystals were ground by an agate mortar for refinement of its optical and magnetic-orientation characters. As a result, we realized a fast-magnetic orientation against the vertical field, which is related to the magnetic control of light reflection, the same as the biogenic guanine crystal behavior.
Si effects on a thermal stability and a crystallization behavior of P-riched Fe(-Si)-B-P-Cu alloys
Authors: Tomita T. , Takahashi T. , Kuwata H.
Published: March 2019

Nanocrystalline soft magnetic ribbons with high saturation magnetic flux density Bs and low coercivity Hc are attracted for high power devices. Ribbon-shaped samples with compositions of Fe83.3B16-xPxCu0.7 (x=4-10) were prepared. The activation energy of the crystallization reaction was estimated by Kissinger’s plot. The value of the Hc after the crystallization reaction was measured. As a result, it was found that as the amount of phosphorus increases, the activation energy of the crystallization reaction increases and the Hc decreases, but ΔTx become smaller. Finally, it turned out that silicon substitution is effective for stabilizing the Hc after heat treatment.
Magnetic anisotropy and crystallographic alignment in Fe and NdH2 during d-HDDR process of Nd-Fe-B-Ga-Nb powders
Authors: Horikawa Takashi , Yamazaki Masao , Mishima Chisato , Matsuura Masashi , Sugimoto Satoshi
Published: March 2019

Hydrogen disproportionation (HD) treatments at 820°C for 10 h with different hydrogen pressures (PHD) were performed for Nd-Fe-B-Ga-Nb magnetic powder to clarify the relationship between the structural differences and resultant magnetic anisotropy as a function of PHD during dynamic hydrogen disproportionation desorption recombination. When PHD was 30 kPa, the anisotropy was the highest after recombination, and coarsened lamellar and spherical structures comprising Fe and NdH2 were observed after HD treatment. In the coarse lamellar structures, the crystallographic orientations of adjacent Fe and NdH2 grains were the same. The diameters of such regions were approximately 1100 nm, and their total area fraction was approximately 70% of the Fe and NdH2 phases. In contrast, when PHD was 100 kPa at which the anisotropy was lower, the sample consisted of mainly spherical grains, and the total area fraction of the regions where adjacent Fe and NdH2 grains exhibited the same crystallographic orientations was small (25%). This result indicates that the presence of coarsened lamellar comprising crystallographically aligned Fe and NdH2 grains contributed significantly to the induction of anisotropy after recombination.
Doubly resonant sum frequency spectroscopy of mixed photochromic isomers on surfaces reveals conformation-specific vibronic effects
Authors: Raab Micah , Becca Jeffrey C. , Heo Jeongyun , Lim Chang-Keun , Baev Alexander , Jensen Lasse , Prasad Paras N. , Velarde Luis
Published: March 2019

Doubly resonant infrared-visible sum-frequency generation (DR-IVSFG) spectroscopy, encompassing coupled vibrational and electronic transitions, provides a powerful method to gain a deep understanding of nuclear motion in photoresponsive surface adsorbates and interfaces. Here, we use DR-IVSFG to elucidate the role of vibronic coupling in a surface-confined donor-acceptor substituted azobenzene. Our study reveals some unique features of DR-IVSFG that have not been previously reported. In particular, vibronic coupling resulted in prominent SFG signal enhancement of selective stretching modes that reveal electronic properties of coexisting photochromic isomers. Our analysis explores two concepts: (1) In partially isomerized azobenzene at the surface, coupling of the fundamental vibrations to the S0 → S1 transition is more prominent for the cis isomer due to symmetry breaking, whereas coupling to the S0 → S2 transition was dominant in the trans isomer. (2) A strong coupling between the fundamental vibrations and the valence π-electron density, promoted by the initial absorption of an infrared photon, may result in suppression of the intensity of the hot band vibronic transition. This may translate into a suppressed sum-frequency generation signal at sum frequency wavelengths resonant with the S0 → S2 transition of the trans isomer. The weaker coupling of the fundamental vibrations to the non-bonding electron density localized on the azo group can therefore produce detectable sum-frequency generation at the resonance wavelength of the weaker S0 → S1 transition in the cis form. These results are explained in the framework of a linear coupling model, involving both Franck-Condon and Herzberg-Teller coupling terms. Our theoretical analysis reveals the important role played by molecular conformation, orientation, and vibronic interference in DR-SFG spectroscopy.
Achieving both high electromechanical response and stable temperature behavior in Si/SiO2/Al/LiTaO3 sandwich structure
Authors: Sun Xueping , Liu Weiguo , Ge Shaobo , Zhou Shun , Li Xiangyang , Lin Dabin
Published: March 2019

In order to realize the following two goals including high electromechanical coupling coefficient (K2) and zero temperature coefficient of frequency (TCF) in a surface acoustic wave (SAW) device, the propagation characteristics of shear-horizontal type (SH-type) boundary waves in the Si/SiO2/Al/LiTaO3 “sandwich” structure are investigated by the three dimensional (3D) finite element method (FEM). The influences of layer SiO2 with different thickness (h) on the SH-type boundary waves characteristics, including the phase velocity (vp), reflection coefficient (kp), K2 and TCF, are theoretically analyzed. The results present that the SH-type boundary wave has a maximum K2 of 4.45% at h/λ=0.62 and has a zero TCF by adjusting h/λ to 0.69. Owing to the acoustic energy distribution approaching to the SiO2/LiTaO3 boundary, the size of Love wave based devices can be reduced to a few wavelength thickness of Si and 36°YX- LiTaO3 crystals, and which also give an opportunity to be integrated onto one chip with subsequent electronic circuits.
Simultaneously precise estimations of phase and amplitude variations based on weak-value amplification
Authors: Luo Lan , Xie Linguo , Qiu Jiangdong , Zhou Xinxing , Liu Xiong , Li Zhaoxue , He Yu , Zhang Zhiyou , Sun Handong
Published: March 2019

In this paper, we theoretically and experimentally present a precision method to simultaneously estimate the phase and amplitude variations of light based on the weak-value amplification. We demonstrate that the imaginary and real components of the weak-value correspond to the amplification of the phase and amplitude variations, respectively. If both the phase and the amplitude are varied, the phase measurement using the imaginary weak-value is not influenced by the amplitude shift and the amplitude measurement using the real weak value is not influenced by the phase shift. Thus, the tiny changes of the phase and amplitude of light can be obtained simultaneously with different post-selections, and the measurement precision reaches ∼10−6 rad. These findings may be favorable for highly sensitive optical polarization-dependent effects, including optical activity and magneto-optic effects.
Self-propelled rotation of paper-based Leidenfrost rotor
Authors: Xu Hao , Thissandier Antoine , Zhao Ruijie , Tao Peng , Song Chengyi , Wu Jianbo , Shang Wen , Deng Tao
Published: March 2019

When a liquid droplet is placed on a sufficiently hot surface, it will be levitated by the vapor cushion between the droplet and the hot surface due to the Leidenfrost effect. Such Leidenfrost-based levitation can greatly reduce friction and thus offers a promising approach for low-friction devices. In this work, we demonstrated a self-propelled rotational Leidenfrost rotor made of wet paper with asymmetric mass distribution. The rotor has shown the capability of reaching angular velocities of more than 30 rad/s and prolonged the rotation duration through refueling with water. We experimentally investigated the influence of mass repartition and substrate heating temperature on the rotation behavior of the rotor. It was found that both the initial acceleration and the maximum angular velocity increase with the increasing mass ratio of the connector over the evaporator within the rotor and the substrate heating temperature. A theoretical model was proposed to simulate the trend, and the simulated results are in good agreement with the experimental results. The paper-based Leidenfrost rotor provides an alternative way to utilize the Leidenfrost effect for exploring self-propelled movement and relevant applications such as surface cleaning and rotary heat engines.
Ultrafast bulk carrier dynamics in various GaN crystals at near-infrared wavelengths under one- and two-photon absorption
Authors: Fang Yu , Yang Junyi , Xiao Zhengguo , Wu Xingzhi , Jia Jidong , Chen Yongqiang , Wu Quanying , Song Yinglin
Published: March 2019

Femtosecond transient absorption (TA) as a probe of ultrafast carrier dynamics was conducted at near-infrared wavelengths in a series of GaN crystals. The TA kinetics in all the GaN crystals appeared to be single exponential under one-photon (1P) excitation but biexponential under two-photon (2P) excitation, which was inconsistent with previous experimental reports and model predictions. Surface recombination and carrier diffusion could be eliminated and the TA responses were identified as phonon-assisted indirect free-carrier absorption. Modelling the bulk carrier dynamics with a simplified model revealed that, at a 1P high carrier injection level, the carrier recombination was limited by the slow capture rate of electrons via deep defects, while at a 2P low carrier injection level, the initial carrier lifetime decreased remarkably due to fast hole capturing and could be further controlled by the inherent carrier and/or dislocation concentrations.
The Barkas effect in plasma transport
Authors: Shaffer Nathaniel R. , Baalrud Scott D.
Published: March 2019

Molecular dynamics simulations reveal that a fundamental symmetry of the plasma kinetic theory is broken at moderate to strong Coulomb coupling: the collision rate depends on the signs of the colliding charges. This symmetry breaking is analogous to the Barkas effect observed in charged-particle stopping experiments and gives rise to significantly enhanced electron-ion collision rates. It is expected to affect any neutral plasma with moderate to strong Coulomb coupling such as ultracold neutral plasmas (UNPs) and the dense plasmas of inertial confinement fusion and laser-matter interaction experiments. The physical mechanism responsible is the screening of binary collisions by the correlated plasma medium, which causes an asymmetry in the dynamics of large-angle scattering. Because the effect pertains only to close interactions, it is not predicted by traditional transport models based on cut-off Coulomb collisions or linear dielectric response. A model for the effective screened interaction potential is presented which is suitable for the coupling strengths achieved in UNP experiments. Transport calculations based on this potential and the effective potential kinetic theory agree with the simulated relaxation rates and predict that the Barkas effect can cause up to a 70% increase in the electron-ion collision rate at the conditions of present UNP experiments. The influence of the Barkas effect in other transport processes is also considered.
Photocurrent measurements of InGaN/GaN quantum wells under hydrostatic and uniaxial pressure
Authors: Bercha Artem , Trzeciakowski Witold , Gładysiewicz-Kudrawiec Marta , Ivonyak Yurii , Grzanka Szymon
Published: March 2019

Light emitting diode structures with InGaN quantum wells have been studied as a function of hydrostatic and uniaxial pressure (along the c-axis) under different values of reverse voltage. Photocurrent measurements (with light parallel to the epitaxial layers) allow determining energies in transverse electric (TE) and transverse magnetic (TM) polarizations, which we attribute to transitions from the heavy-hole (HH) and crystal-field split (CH) band to the conduction band. The comparison of theory and experiment suggests that the electric fields are about 25% lower than the calculated values. The transitions in TE polarization agree with the theoretical predictions, while those in TM polarization do not. In particular, the splittings between HH and CH bands are lower than the theoretical predictions.
Effect of Aging Methods on CuZnAl Catalysts for Methyl Acetate Hydrogenation
Authors: Gan Changna , Wang Yunhao , Ye Chenliang , Guo Cuili
Published: March 2019

A series of CuZnAl catalysts derived from layered double hydroxide precursors with different Cu/Zn molar ratios were synthesised by a co-precipitation method for methyl acetate hydrogenation. The best catalytic performance was obtained when the Cu/Zn molar ratio reached 0.25:1. After fixing the Cu/Zn molar ratio at 0.25:1, the effect of aging methods, including ultrasound, high shear mixer stirring, and magnetic stirring, were investigated, which showed that 0.25CuZnAl-u and 0.25CuZnAl-h exhibited a higher conversion and selectivity than that of 0.25CuZnAl-m, especially under low reaction temperatures. The physicochemical properties of the CuZnAl catalysts were characterised by X-ray diffraction, inductively coupled plasma–atomic emission spectroscopy, N2 physisorption, N2O chemisorption, transmission electron microscopy, H2-temperature-programmed reduction, X-ray photoelectron spectroscopy, and H2-temperature-programmed desorption. It was found that compared with 0.25CuZnAl-m, 0.25CuZnAl-u and 0.25CuZnAl-h possessed a stronger interaction between Cu and the support, smaller copper particle size, and higher copper dispersion, which improved the catalytic performance.
Divergence of the quadrupole-strain susceptibility of the electronic nematic system YbRu
2
Ge
2
Authors: Rosenberg Elliott W. , Chu Jiun-Haw , Ruff Jacob P. C. , Hristov Alexander T. , Fisher Ian R.
Published: March 2019

Significance

A wide range of strongly correlated quantum materials, including some high-temperature superconductors, exhibit “electronic nematic” phases, in which the electronic properties spontaneously break the rotational symmetry of the crystal. However, the role that the corresponding nematic fluctuations play in these complicated systems is unclear, motivating the search for simpler model systems. Here, we identify a particular 4
f
intermetallic material which exhibits ferroquadrupole order,

Y
b
R
u

2

G
e

2

, as just such a model system. We also provide a robust and accurate method to probe the divergence of an important associated quantity, the quadrupole-strain susceptibility. The temperature dependence of this quantity provides insight into the nature of the interactions that lead to ferroquadrupole order, in this case, magnetoelastic coupling.
Effect of orientation on low-cycle fatigue behaviour of single crystal superalloys at 900°C
Authors: Li Peng , Zhou Bomou , Zhou Yizhou , Zhang Zhefeng
Published: March 2019

Low-cycle fatigue tests on [001], [011] and [Formula: see text] Ni-based single crystal superalloys were conducted at 900°C under a constant plastic strain control. Cracks will more readily propagate between the {111} planes than migrate between the {111} and {001} planes, as shown by the longer crack propagation period and fatigue life for each [001] specimen (all crystal orientations). The oxidation could proceed via two different diffusion paths: short-range diffusion and long-range diffusion. Fatigue cracks prefer to nucleate at one oxide and then propagate along the oxidised slip bands until they link to the next oxide, which could be predicted from fatigue crack growth data, including the fractographic slip band density and oxide depth.
Twinning and its effect on the evolution of acicular α in Ti–5Al–5Mo–5V–3Cr–1Zr
Authors: Li Shaojun , Lv Yaping , Zhang Xiaoyong , Chen Chao , Zhou Kechao
Published: March 2019

Near β titanium alloy Ti–5Al–5Mo–5V–3Cr–1Zr with acicular α microstructure was hot compressed at 750°C/10−3 s−1. Twinning and its effect on the evolution of acicular α were investigated. Twinning is induced from the dislocations pile-up at α/β boundary. The twinning system is [Formula: see text]. During twinning, one type of pure shear displacement and three types of shuffle + shear mixed displacement are confirmed. The twinning dislocation can be expressed as ( b, 4 h0), [Formula: see text], h0 is the interplanar distance of [Formula: see text], [Formula: see text], κ = c/a. Substructures form in acicular α through the migration of twin boundary, followed by meeting another neighbouring parallel twin and then causing the twins-merging. And the accumulation of the twinning displacement results in the bending of acicular α.
Optimisation of imaging flow cytometry for the analysis of single extracellular vesicles by using fluorescence‐tagged vesicles as biological reference material
Authors: Görgens André , Bremer Michel , Ferrer‐Tur Rita , Murke Florian , Tertel Tobias , Horn Peter A. , Thalmann Sebastian , Welsh Joshua A. , Probst Christine , Guerin Coralié , Boulanger Chantal M. , Jones Jennifer C. , Hanenberg Helmut , Erdbrügger Uta , Lannigan Joanne , Ricklefs Franz L. , El‐Andaloussi Samir , Giebel Bernd
Published: March 2019

Extracellular vesicles (EVs) mediate targeted cellular interactions in normal and pathophysiological conditions and are increasingly recognised as potential biomarkers, therapeutic agents and drug delivery vehicles. Based on their size and biogenesis, EVs are classified as exosomes, microvesicles and apoptotic bodies. Due to overlapping size ranges and the lack of specific markers, these classes cannot yet be distinguished experimentally. Currently, it is a major challenge in the field to define robust and sensitive technological platforms being suitable to resolve EV heterogeneity, especially for small EVs (sEVs) with diameters below 200 nm, i.e. smaller microvesicles and exosomes. Most conventional flow cytometers are not suitable for the detection of particles being smaller than 300 nm, and the poor availability of defined reference materials hampers the validation of sEV analysis protocols. Following initial reports that imaging flow cytometry (IFCM) can be used for the characterisation of larger EVs, we aimed to investigate its usability for the characterisation of sEVs. This study set out to identify optimal sample preparation and instrument settings that would demonstrate the utility of this technology for the detection of single sEVs. By using CD63eGFP‐labelled sEVs as a biological reference material, we were able to define and optimise IFCM acquisition and analysis parameters on an Amnis ImageStreamX MkII instrument for the detection of single sEVs. In addition, using antibody‐labelling approaches, we show that IFCM facilitates robust detection of different EV and sEV subpopulations in isolated EVs, as well as unprocessed EV‐containing samples. Our results indicate that fluorescently labelled sEVs as biological reference material are highly useful for the optimisation of fluorescence‐based methods for sEV analysis. Finally, we propose that IFCM will help to significantly increase our ability to assess EV heterogeneity in a rigorous and reproducible manner, and facilitate the identification of specific subsets of sEVs as useful biomarkers in various diseases.
PIP4K2A as a negative regulator of PI3K in PTEN-deficient glioblastoma
Authors: Shin Yong Jae , Sa Jason K. , Lee Yeri , Kim Donggeon , Chang Nakho , Cho Hee Jin , Son Miseol , Oh Michael Y.T. , Shin Kayoung , Lee Jin-Ku , Park Jiwon , Jo Yoon Kyung , Kim Misuk , Paddison Patrick J. , Tergaonkar Vinay , Lee Jeongwu , Nam Do-Hyun
Published: March 2019

Glioblastoma (GBM) is the most malignant brain tumor with profound genomic alterations. Tumor suppressor genes regulate multiple signaling networks that restrict cellular proliferation and present barriers to malignant transformation. While bona fide tumor suppressors such as PTEN and TP53 often undergo inactivation due to mutations, there are several genes for which genomic deletion is the primary route for tumor progression. To functionally identify putative tumor suppressors in GBM, we employed in vivo RNAi screening using patient-derived xenograft models. Here, we identified PIP4K2A, whose functional role and clinical relevance remain unexplored in GBM. We discovered that PIP4K2A negatively regulates phosphoinositide 3-kinase (PI3K) signaling via p85/p110 component degradation in PTEN-deficient GBMs and specifically targets p85 for proteasome-mediated degradation. Overexpression of PIP4K2A suppressed cellular and clonogenic growth in vitro and impeded tumor growth in vivo. Our results unravel a novel tumor-suppressive role of PIP4K2A for the first time and support the feasibility of combining oncogenomics with in vivo RNAi screen.
A Dictionary of Agriculture and Land Management
Authors: Manley Will , Foot Katharine , Davis Andrew
Published: March 2019

Over 2,000 entries

This new dictionary covers both agriculture and land management, including animals and crops, farm machinery and systems, estate management, forestry and woodland, the environment, and rural recreation. It addresses the increasing overlap between agricultural sectors and the demands of the management of rural land and property.

Offering authoritative and up-to-date information on subjects ranging from soil management and renewable energy to land law, tourism, types of trees and crops, and organizations, policies, and legislation, it is an invaluable guide to agricultural terminology and a must-have for students of agriculture and land management, as well as for professionals in the agricultural and land-management sectors. Entries are complemented by illustrations and tables, including types of trees, crops, and soils, as well as of farm animals and diseases.
History of Benzodiazepine Prescriptions and Risk of Dementia: Possible Bias Due to Prevalent Users and Covariate Measurement Timing in a Nested Case-Control Study
Authors: Richardson Kathryn , Mattishent Katharina , Loke Yoon K , Steel Nicholas , Fox Chris , Grossi Carlota M , Bennett Kathleen , Maidment Ian , Boustani Malaz , Matthews Fiona E , Myint Phyo K , Campbell Noll L , Brayne Carol , Robinson Louise , Savva George M
Published: March 2019

Previous estimates of whether long-term exposure to benzodiazepines increases dementia risk are conflicting and are compromised by the difficulty of controlling for confounders and by reverse causation. We investigated how estimates for the association between benzodiazepine use and later dementia incidence varied based on study design choices, using a case-control study nested within the United Kingdom’s Clinical Practice Research Datalink. A total of 40,770 dementia cases diagnosed between April 2006 and July 2015 were matched on age, sex, available data history, and deprivation to 283,933 control subjects. Benzodiazepines and Z-drug prescriptions were ascertained in a drug-exposure period 4–20 years before dementia diagnosis. Estimates varied with the inclusion of new or prevalent users, with the timing of covariate ascertainment, and with varying time between exposure and outcome. There was no association between any new prescription of benzodiazepines and dementia (adjusted odds ratio (OR) = 1.03, 95% confidence interval (CI): 1.00, 1.07), whereas an inverse association was observed among prevalent users (adjusted OR = 0.91, 95% CI: 0.87, 0.95), although this was likely induced by unintentional adjustment for colliders. By considering the choice of confounders and timing of exposure and covariate measurement, our findings overall are consistent with no causal effect of benzodiazepines or Z-drugs on dementia incidence.
Invited Commentary: The Causal Association Between Obesity and Stillbirth—Strengths and Limitations of the Consecutive-Pregnancies Approach
Authors: Snowden Jonathan M , Leonard Stephanie A
Published: March 2019

There has been a resurgence in analyses of consecutive pregnancies (or similarly, sibling designs) in perinatal and pediatric epidemiology. These approaches have attractive qualities for estimating associations with complex multifactorial exposures like obesity. In an article appearing in this issue of the Journal, Yu et al. (Am J Epidemiol. 2019;188(7):1328–1336) apply a consecutive-pregnancies approach to characterize the risk of stillbirth among women who develop obesity between pregnancies (“incident obesity”). Working within a causal framework and using parametric and nonparametric estimation techniques, the authors find an increase in stillbirth risk associated with incident obesity. Risk differences varied between 0.4 per 1,000 births (95% confidence interval (CI): 0.1, 0.7) and 6.9 per 1,000 births (95% CI: 3.7, 10.0), and risk ratios ranged from 1.12 (95% CI: 1.02, 1.23) to 2.99 (95% CI: 2.19, 4.08). The strengths of this approach include starting from a clearly defined causal estimand and exploring the sensitivity of parameter estimates to model selection. In this commentary, we put these findings in the broader context of research on obesity and birth outcomes and highlight concerns regarding the generalizability of results derived from within-family designs. We conclude that while causal inference is an important goal, in some instances focusing on formulation of a causal question drives results away from broad applicability.
Comparison of Parametric and Nonparametric Estimators for the Association Between Incident Prepregnancy Obesity and Stillbirth in a Population-Based Cohort Study
Authors: Yu Ya-Hui , Bodnar Lisa M , Brooks Maria M , Himes Katherine P , Naimi Ashley I
Published: March 2019

While prepregnancy obesity increases risk of stillbirth, few studies have evaluated the role of newly developed obesity independent of long-standing obesity. Additionally, researchers have relied almost exclusively on parametric models, which require correct specification of an unknown function for consistent estimation. We estimated the association between incident obesity and stillbirth in a cohort constructed from linked birth and death records in Pennsylvania (2003–2013). Incident obesity was defined as body mass index (weight (kg)/height (m)2) greater than or equal to 30. We used parametric G-computation, semiparametric inverse-probability weighting, and parametric/nonparametric targeted minimum loss-based estimation (TMLE) to estimate the association between incident prepregnancy obesity and stillbirth. Compared with pregnancies from women who stayed nonobese, women who became obese prior to their next pregnancy were estimated to have 2.0 (95% confidence interval (CI): 0.5, 3.5) more stillbirths per 1,000 pregnancies using parametric G-computation. However, despite well-behaved stabilized inverse probability weights, risk differences estimated from inverse-probability weighting, nonparametric TMLE, and parametric TMLE represented 6.9 (95% CI: 3.7, 10.0), 0.4 (95% CI: 0.1, 0.7), and 2.9 (95% CI: 1.5, 4.2) excess stillbirths per 1,000 pregnancies, respectively. These results, particularly those derived from nonparametric TMLE, were highly sensitive to covariates included in the propensity score models. Our results suggest that caution is warranted when using nonparametric estimators to quantify exposure effects.
Pancreatic AT1aR Deficiency Decreases Insulin Secretion in Obese C57BL/6 Mice
Authors: Shoemaker Robin , AlSiraj Yasir , Chen Jeff , Cassis Lisa A
Published: March 2019

BACKGROUND

Previously, we demonstrated that obese mice have marked elevations in systemic concentrations of angiotensin II (AngII). Drugs that inhibit the renin–angiotensin system (RAS), including angiotensin type 1 receptor (AT1R) antagonists, have been reported to delay the onset of type 2 diabetes (T2D), suggesting improvements in insulin sensitivity or regulation of pancreatic insulin secretion. Pancreatic islets possess components of the RAS, including AT1R, but it is unclear if AngII acts at islets to regulate insulin secretion during the development of T2D.

METHODS

We deleted AT1aR from pancreatic islets and examined effects on insulin secretion in mice fed a low-fat (LF) or high-fat (HF) diet. In separate studies, to exacerbate the system, we infused HF-fed mice of each genotype with AngII.

RESULTS

Pancreatic AT1aR deficiency impaired glucose tolerance and elevated plasma glucose concentrations in HF, but not LF-fed mice. In HF-fed mice, high glucose increased insulin secretion from islets of AT1aRfl/fl, but not AT1aRpdx mice. In AngII-infused mice, following glucose challenge, plasma glucose or insulin concentrations were not significantly different between genotypes. Moreover, high glucose stimulated insulin secretion from islets of AT1aRfl/fl and AT1aRpdx mice, presumably related to weight loss, and improved insulin sensitivity in both groups of AngII-infused HF-fed mice.

CONCLUSIONS

Our results suggest that during the adaptive response to insulin resistance from HF feeding, AngII promotes insulin secretion from islets through an AT1aR mechanism. These results suggest the timing of initiation of AT1R blockade may be important in the progression from prediabetes to T2D with β-cell failure.