bluuebunny/crossref_metadata_2025 huggingface dataset:
Tamm plasmon sub-wavelength structuration for loss reduction and resonance tuning
Authors: Gubaydullin A. R. , Symonds C. , Benoit J.-M. , Ferrier L. , Benyattou T. , Jamois C. , Lemaître A. , Senellart P. , Kaliteevski M. A. , Bellessa J.
Published: December 2017

We have demonstrated experimentally and theoretically that losses in Tamm plasmon structures can be reduced by using a subwavelength structuration of the metal layer. The structures consist of a GaAs/Al0.95Ga0.05As Bragg reflector covered with a sub-wavelength silver grating. An active quantum dot layer is inserted to perform photoluminescence experiments. Experimental results show that the quality factor of the Tamm plasmon mode with grating increases substantially, with respect to the same structure without a grating. Moreover, a fine-tuning of the Tamm spectral position is obtained by changing the grating parameters. Finite element method simulations are in good agreement with the experimental values. Our results will promote the realization of lasing with the TP based devices at room temperature.
Miniature ion thruster ring-cusp discharge performance and behavior
Authors: Dankongkakul Ben , Wirz Richard E.
Published: December 2017

Miniature ion thrusters are an attractive option for a wide range of space missions due to their low power levels and high specific impulse. Thrusters using ring-cusp plasma discharges promise the highest performance, but are still limited by the challenges of efficiently maintaining a plasma discharge at such small scales (typically 1–3 cm diameter). This effort significantly advances the understanding of miniature-scale plasma discharges by comparing the performance and xenon plasma confinement behavior for 3-ring, 4-ring, and 5-ring cusp by using the 3 cm Miniature Xenon Ion thruster as a modifiable platform. By measuring and comparing the plasma and electron energy distribution maps throughout the discharge, we find that miniature ring-cusp plasma behavior is dominated by the high magnetic fields from the cusps; this can lead to high loss rates of high-energy primary electrons to the anode walls. However, the primary electron confinement was shown to considerably improve by imposing an axial magnetic field or by using cathode terminating cusps, which led to increases in the discharge efficiency of up to 50%. Even though these design modifications still present some challenges, they show promise to bypassing what were previously seen as inherent limitations to ring-cusp discharge efficiency at miniature scales.
Experimental examination of tunneling paths in SiGe/Si gate-normal tunneling field-effect transistors
Authors: Glass S. , von den Driesch N. , Strangio S. , Schulte-Braucks C. , Rieger T. , Narimani K. , Buca D. , Mantl S. , Zhao Q. T.
Published: December 2017

The benefits of a gate-normal tunneling architecture in enhancing the on-current and average subthreshold swing of tunneling field-effect transistors were scrutinized in experiment through careful physical analysis of a Si0.50Ge0.50/Si heterostructure. In accordance with theoretical predictions, it is confirmed that the on-current is governed by line tunneling scaling with the source-gate overlap area of our devices. Our analysis identifies the early onset of parasitic diagonal tunneling paths as most detrimental for a low average subthreshold swing. By counter doping the channel, this onset can be shifted favorably, permitting low average subthreshold swings down to 87 mV/dec over four decades of drain current and high on-off current ratios exceeding 106.
Charge migration and charge transfer in molecular systems
Authors: Wörner Hans Jakob , Arrell Christopher A. , Banerji Natalie , Cannizzo Andrea , Chergui Majed , Das Akshaya K. , Hamm Peter , Keller Ursula , Kraus Peter M. , Liberatore Elisa , Lopez-Tarifa Pablo , Lucchini Matteo , Meuwly Markus , Milne Chris , Moser Jacques-E. , Rothlisberger Ursula , Smolentsev Grigory , Teuscher Joël , van Bokhoven Jeroen A. , Wenger Oliver
Published: December 2017

The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.
Uniform areal-distribution of UV intensity by synchronizing signal-waveforms and position of a UV-LED array
Authors: Takahashi H. , Shimoyama I. , Heo Y. J.
Published: December 2017

This paper describes a theoretical approach to give an irradiated area a uniform distribution of LED light intensity by synchronizing the signal waveforms and position control of the LEDs. Although UV-LEDs have attracted considerable attention as alternative light sources for ultraviolet (UV) lithography in Micro Electro Mechanical Systems (MEMS) fabrication, mainly because of their low cost and low power consumption, the realization of a uniform UV intensity over an area remains challenging. Here, we propose a method to achieve a uniform areal intensity within an irradiated area by synchronizing the signal waveform and position of a UV-LED array. To verify our theoretical calculation, we developed a system with a UV-LED array whose position is controlled by a linear actuator. The intensity of the UV-LED array is controlled by a pulse width modulation (PWM) signal, which is synchronized with the position of the linear actuator. Using this system, we fabricated 2D micropatterns and 3D microstructures with high uniformity in the irradiated area. The proposed method is expected to facilitate practical LED-based lithography in MEMS fabrication.
The impact of membrane surface charges on the ion transport in MoS2 nanopore power generators
Authors: Huang Zhuo , Zhang Yan , Hayashida Tomoki , Ji Ziwei , He Yuhui , Tsutsui Makusu , Miao Xiang Shui , Taniguchi Masateru
Published: December 2017

Recent experiments demonstrated giant osmotic effects induced in a single-atomic-layer MoS2 nanopore by imposing a KCl concentration bias, thereby highlighting the prospect of ultrathin nanopores as power generators. In this work, we report on an electrokinetic analysis of the ionic transport in the MoS2 nanopore system. By taking membrane surface chemistry into account, we found profound roles of surface charges in and out of the nanopore on the cross-pore ion transport, which shed light on the intriguing experimental observations of a high pore conductance with a large open-circuit voltage in the MoS2 system. The present work establishes a theoretical model capable of dealing with ultrathin membrane surface charges for evaluating the energy conversion performance of nanopore power generators constructed with two-dimensional materials.
Attosecond light pulses generation along the target surface driven by obliquely-incident lasers
Authors: Zhang Y. X. , Qiao B. , Xu X. R. , Chang H. X. , Zhang H. , Lu H. Y. , Yu M. Y. , Zhou C. T. , Zhu S. P. , He X. T.
Published: December 2017

A practical approach to achieve strong coherent synchrotron emissions (CSE) in relativistic laser-plasma interaction is proposed, where a plane target with its electron density satisfying the self-similar parameter S≃ne0/a0nc=1 is obliquely irradiated by a P-polarized laser pulse. In this case, electrons at the target surface are periodically dragged out into the vacuum by the laser field component perpendicular to the target surface, resulting in the formation of a series of dense electron bunches propagating along the target surface. Intense CSE is generated by these electron bunches under acceleration by the laser field component parallel to the target surface. Two-dimensional particle-in-cell simulations show that an intense attosecond light pulse at intensity 9.1 × 1020 W/cm2 (electric field strength ∼41% as that of the drive laser) can be obtained through such CSE. In the high-order harmonics with 15ω0<ωn<500ω0 (ω0 is the laser frequency), the power spectrum of the emission scales as I(n)∼n−1.8 and the conversion efficiency from laser to emission reaches ∼10−2.
Performance comparison between photovoltaic and thermoradiative devices
Authors: Lin Chungwei , Wang Bingnan , Teo Koon Hoo , Zhang Zhuomin
Published: December 2017

Photovoltaic (PV) and thermoradiative (TR) devices are power generators that use the radiative energy transfer between a hot and a cold reservoir. For PV devices, the semiconductor at the cold side (PV cell) generates electric power; for TR devices, the semiconductor at the hot side (TR cell) generates electric power. In this work, we compare the performance of the photovoltaic and thermoradiative devices, with and without the non-radiative processes. Without non-radiative processes, PV devices generally produce larger output powers than TR devices. However, when non-radiative processes become important, the TR can outperform the PV devices. This conclusion applies to both far-field and near-field based devices. A key difference in efficiency between PV and TR devices is pointed out.
High temperature GaAs X-ray detectors
Authors: Lioliou G. , Whitaker M. D. C. , Barnett A. M.
Published: December 2017

Two GaAs p+-i-n+ mesa X-ray photodiodes were characterized for their electrical and photon counting X-ray spectroscopic performance over the temperature range of 100 °C to –20 °C. The devices had 10 μm thick i layers with different diameters: 200 μm (D1) and 400 μm (D2). The electrical characterization included dark current and capacitance measurements at internal electric field strengths of up to 50 kV/cm. The determined properties of the two devices were compared with previously reported results that were made with a view to informing the future development of photon counting X-ray spectrometers for harsh environments, e.g., X-ray fluorescence spectroscopy of planetary surfaces in high temperature environments. The best energy resolution obtained (Full Width at Half Maximum at 5.9 keV) decreased from 2.00 keV at 100 °C to 0.66 keV at –20 °C for the spectrometer with D1, and from 2.71 keV at 100 °C to 0.71 keV at –20 °C for the spectrometer with D2. Dielectric noise was found to be the dominant source of noise in the spectra, apart from at high temperatures and long shaping times, where the main source of photopeak broadening was found to be the white parallel noise.
Enhancement of the thermoelectric performance of oxygen substituted bismuth telluride
Authors: Van Quang Tran , Kim Miyoung
Published: December 2017

We carried out first-principles calculations based on density functional theory and the semi-classical Boltzmann transport theory to study the effect of oxygen substitution on the electronic structure and thermoelectric properties of bismuth telluride. The newly formed compound, Bi2O2Te, is found to be a narrow bandgap semiconductor with the bandgap of Eg = 0.13 eV. The presence of a flat band close to the valence band maximum gives rise to a steep slope of density of states near Fermi energy, leading to a significant enhancement of the Seebeck coefficient. As a result, the thermoelectric power factor of Bi2O2Te is significantly improved by controlling the carrier concentration, and the maximum power factor increased with temperature. Assuming the experiment-thermal conductivity, Bi2O2Te exhibits a high figure of merit of ZT ∼1.27 around 600 K for the p-type doping, which matches or exceeds ZT of the state-of-the-art thermoelectric materials in this temperature range. This suggests that Bi2O2Te with p-type doping is a new promising material for use in the moderate-temperature thermoelectric energy conversion.
Structural and electron transport properties of single-crystalline In2O3 films compensated by Ni acceptors
Authors: Papadogianni Alexandra , Kirste Lutz , Bierwagen Oliver
Published: December 2017

For device applications, the ability to grow semi-insulating or p-type indium oxide (In2O3) is highly desirable. With this in focus, high quality single-crystalline Ni-doped In2O3 films have been grown by plasma-assisted molecular beam epitaxy and structurally and electrically characterized. Within a concentration range of approximately 1017–1019 cm−3, Ni is fully incorporated in the In2O3 lattice without the formation of secondary phases. At doping higher than roughly 1020 cm−3, secondary phases seem to start forming. No film exhibits p-type conductivity at room temperature. Instead, Ni is shown to be a deep compensating acceptor—confirming theoretical calculations, the effect of which only becomes apparent after annealing in oxygen. Combined Hall and Seebeck measurements reveal the compensation of bulk donors already at low Ni concentrations (∼1018 cm−3) and a residual film conductance due to mainly the interface region to the substrate. This residual conductance is gradually pinched off with increasing Ni doping, eventually resulting in semi-insulating films at excessive Ni concentrations (∼1021 cm−3).
Performance investigation on DCSFCL considering different magnetic materials
Authors: Yuan Jiaxin , Zhou Hang , Zhong Yongheng , Gan Pengcheng , Gao Yanhui , Muramatsu Kazuhiro , Du Zhiye , Chen Baichao
Published: December 2017

In order to protect high voltage direct current (HVDC) system from destructive consequences caused by fault current, a novel concept of HVDC system fault current limiter (DCSFCL) was proposed previously. Since DCSFCL is based on saturable core reactor theory, iron core becomes the key to the final performance of it. Therefore, three typical kinds of soft magnetic materials were chosen to find out their impact on performances of DCSFCL. Different characteristics of materials were compared and their theoretical deductions were carried out, too. In the meanwhile, 3D models applying those three materials were built separately and finite element analysis simulations were performed to compare these results and further verify the assumptions. It turns out that materials with large saturation flux density value Bs like silicon steel and short demagnetization time like ferrite might be the best choice for DCSFCL, which can be a future research direction of magnetic materials.
Growth of room temperature ferromagnetic Ge1-xMnx quantum dots on hydrogen passivated Si (100) surfaces
Authors: Gastaldo Daniele , Conta Gianluca , Coïsson Marco , Amato Giampiero , Tiberto Paola , Allia Paolo
Published: December 2017

A method for the synthesis of room-temperature ferromagnetic dilute semiconductor Ge1-xMnx (5 % < x < 8 %) quantum dots by molecular beam epitaxy by selective growth on hydrogen terminated silicon (100) surface is presented. The functionalized substrates, as well as the nanostructures, were characterized in situ by reflection high-energy electron diffraction. The quantum dots density and equivalent radius were extracted from field emission scanning electron microscope pictures, obtained ex-situ. Magnetic characterizations were performed by superconducting quantum interference device vibrating sample magnetometry revealing that ferromagnetic order is maintained up to room temperature: two different ferromagnetic phases were identified by the analysis of the field cooled – zero field cooled measurements.
A magnetic braking and sensing technique for deceleration and recovery of moving non-magnetic metallic particles
Authors: Cheng David , Yoshinaka Akio , Wu Lawrence
Published: December 2017

A magnetic braking and sensing technique developed as a potential alternative to assist with the non-contact deceleration and detection of explosively dispersed non-magnetic metallic particles is discussed. In order to verify the feasibility of such a technique and gain an understanding of how the underlying forces scale with particle size and velocity, a study was conducted whereby an aluminum particle moving along a spatially varying but time-invariant magnetic field was modeled and the corresponding experiment performed.
Electric field dependence on the conductivity of Kapton-HN: Integration into a 1D physical model used for the description of charge transport in dielectric materials under space environment
Authors: Pacaud Rémi , Paulmier Thierry , Sarrailh Pierre
Published: December 2017

In this paper, the development of a 1D physical conductivity model that describes charge transport in dielectric materials under space radiations with application to Kapton-HN is discussed. This model allows a good description of the charging behavior in dielectric materials. Former experiment run at ONERA on Kapton-HN showed that conductivity is temperature and electric field dependent. These results confirmed the need of implementing these dependences to our 1D model. This paper focuses on the electric field dependence. After a thorough analysis in the literature, several physical theories have been found that can explain this electric field dependence on the conductivity. They are the Onsager theory and the electric field assisted de-trapping mechanisms: direct tunneling, hopping transport, and the Poole-Frenkel theory. This paper is divided as follows: first the experiments that brought into evidence the electric field dependence of the conductivity in Kapton-HN are pointed out. Then the theories that could explain this dependence are described and implemented into the model. Finally, numerical and experimental conductivity results are compared and presented in the last sections.
Discharge mode transition and temporal-spatial evolution of an air-water plasma jet generated by pulsating DC power
Authors: Lei J. , Geng Y. , Liu K. , Zhu W. , Zheng Z. , Hu H.
Published: December 2017

In this paper, pulsating direct current air-water plasma jet, which can increase the production of •OH and decrease the temperature, is studied. The results show that the discharge mode changes in one cycle from corona discharge with steep Trichel current pulse to glow-like discharge. It is unknown whether the different discharge modes and water ratio have an effect on the transient process of the excited O and •OH production and the mechanism of plasma propagation. So, a series of experiments are done in this paper. The results show that the changing rules of both the excited state O and the discharge current reach their two peak values synchronously. And its maximum appears at the time of the first peak current value in corona mode. However, the change of the excited state •OH is different. It increases to its maximum at the time of the second peak current value in glow-like mode. Besides, the intensified charge coupled device photographs show that the luminous intensity of the discharge zone at the first peak current value in corona mode is stronger than the second peak current value in glow-like mode. At the same time, the discharge area of the former is larger than the latter. Nevertheless, with the increase in water ratio, the discharge area change reversed. Additionally, the air plasma plume propagation depends on the gas flow. The initial propagation velocity decreases with the increase in water ratio.
Impact of open-core threading dislocations on the performance of AlGaN metal-semiconductor-metal photodetectors
Authors: Walde S. , Brendel M. , Zeimer U. , Brunner F. , Hagedorn S. , Weyers M.
Published: December 2017

The influence of open-core threading dislocations on the bias-dependent external quantum efficiency (EQE) of bottom-illuminated Al0.5Ga0.5N/AlN metal-semiconductor-metal (MSM) photodetectors (PDs) is presented. These defects originate at the Al0.5Ga0.5N/AlN interface and terminate on the Al0.5Ga0.5N surface as hexagonal prisms. They work as electrically active paths bypassing the Al0.5Ga0.5N absorber layer and therefore alter the behavior of the MSM PDs under bias voltage. This effect is included in the model of carrier collection in the MSM PDs showing a good agreement with the experimental data. While such dislocations usually limit the device performance, the MSM PDs benefit by high EQE at a reduced bias voltage while maintaining a low dark current.
A high-gain and high-efficiency X-band triaxial klystron amplifier with two-stage cascaded bunching cavities
Authors: Zhang Wei , Ju Jinchuan , Zhang Jun , Zhong Huihuang
Published: December 2017

To achieve GW-level amplification output radiation at the X-band, a relativistic triaxial klystron amplifier with two-stage cascaded double-gap bunching cavities is investigated. The input cavity is optimized to obtain a high absorption rate of the external injection microwave. The cascaded bunching cavities are optimized to achieve a high depth of the fundamental harmonic current. A double-gap standing wave extractor is designed to improve the beam wave conversion efficiency. Two reflectors with high reflection coefficients both to the asymmetric mode and the TEM mode are employed to suppress the asymmetric mode competition and TEM mode microwave leakage. Particle-in-cell simulation results show that a high power microwave with a power of 2.53 GW and a frequency of 8.4 GHz is generated with a 690 kV, 9.3 kA electron beam excitation and a 25 kW seed microwave injection. Particularly, the achieved power conversion efficiency is about 40%, and the gain is as high as 50 dB. Meanwhile, there is insignificant self-excitation of the parasitic mode in the proposed structure by adopting the reflectors. The relative phase difference between the injected signals and the output microwaves keeps locked after the amplifier becomes saturated.
Role of plasma membrane surface charges in dictating the feasibility of membrane-nanoparticle interactions
Authors: Sinha Shayandev , Jing Haoyuan , Sachar Harnoor Singh , Das Siddhartha
Published: December 2017

Receptor-ligand (R-L) binding mediated interactions between the plasma membrane (PM) and a nanoparticle (NP) require the ligand-functionalized NPs to come to a distance of separation (DOS) of at least dRL (length of the R-L complex) from the receptor-bearing membranes. In this letter, we establish that the membrane surface charges and the surrounding ionic environment dictate whether or not the attainment of such a critical DOS is possible. The negatively charged membrane invariably induces a negative electrostatic potential at the NP surface, repelling the NP from the membrane. This is countered by the attractive influences of the thermal fluctuations and van der Waals (vdw) interactions that drive the NP close to the membrane. For a NP approaching the membrane from a distance, the ratio of the repulsive (electrostatic) and attractive (thermal and vdW) effects balances at a critical NP-membrane DOS of dg,c. For a given set of parameters, there can be two possible values of dg,c, namely, dg,c,1 and dg,c,2 with dg,c,1 ≫ dg,c,2. We establish that any R-L mediated NP-membrane interaction is possible only if dRL > dg,c,1. Therefore, our study proposes a design criterion for engineering ligands for a NP that will ensure the appropriate length of the R-L complex in order to ensure the successful membrane-NP interaction in the presence of a given electrostatic environment. Finally, we discuss the manner in which our theory can help designing ligand-grafted NPs for targeted drug delivery, design biomimetics NPs, and also explain various experimental results.
Geometric scalings for the electrostatically driven helical plasma state
Authors: Akçay Cihan , Finn John M. , Nebel Richard A. , Barnes Daniel C.
Published: December 2017

A new plasma state has been investigated [Akcay et al., Phys. Plasmas 24, 052503 (2017)], with a uniform applied axial magnetic field in a periodic cylinder of length L=2πR, driven by helical electrodes. The drive is single helicity, depending on mθ+kz=mθ−nζ, where ζ=z/R and k=−n/R. For strong (m,n)=(1,1) drive, the state was found to have a strong axial mean current density, with a mean-field safety factor q0(r) just above the pitch of the electrodes m/n=1 in the interior. This state has possible applications to DC electrical transformers and tailoring of the current profile in tokamaks. We study two geometric issues of interest for these applications: (i) scaling of properties with the plasma length or aspect ratio and (ii) behavior for different helicities, specifically (m,n)=(1,n) for n > 1 and (m,n)=(2,1).
Tunable microwave properties of rhomboid shaped nanomagnet pairs
Authors: Tian Chang , Adeyeye Adekunle Olusola
Published: December 2017

The magnetization dynamics of a multilayer rhomboid shaped nanomagnet pair is investigated using micro-focused Brillouin light scattering spectroscopy. The multilayer structure consists of two permalloy layers separated by a nonmagnetic Cr spacer layer. As compared with a single-layer rhomboid shaped nanomagnet pair with two distinct magnetic ground states (ferromagnetic and antiferromagnetic), the multilayer nanomagnetic pair displays multiple magnetic ground states upon different initialization fields due to the presence of both in-plane and out-of-plane dipolar coupling. The dynamic response as a function of initialization field has been systematically investigated. Distinct microwave absorption behavior and resonance frequency shift are observed when the nanomagnet pair is switched into different magnetic ground states. Micromagnetic simulations validate our experimental observations.
Affinity purification mass spectrometry analysis of PD-1 uncovers SAP as a new checkpoint inhibitor
Authors: Peled Michael , Tocheva Anna S. , Sandigursky Sabina , Nayak Shruti , Philips Elliot A. , Nichols Kim E. , Strazza Marianne , Azoulay-Alfaguter Inbar , Askenazi Manor , Neel Benjamin G. , Pelzek Adam J. , Ueberheide Beatrix , Mor Adam
Published: December 2017

Significance

Antibodies targeting PD-1 have elicited clinical responses in multiple tumors. Nevertheless, response to anti–PD-1 interventions is limited to a fraction of patients, and a comprehensive understanding of the signaling downstream of PD-1 could provide biomarkers for tumor response. We used affinity purification-mass spectrometry to uncover proteins associated with PD-1 and found that the adaptor protein SAP inhibits PD-1 functions by blocking the enzymatic interaction between the phosphatase SHP2 and the subset of its substrates that also bind to SAP. Signaling downstream of PD-1 in T cell subsets did not correlate with PD-1 expression but was inversely correlated with SAP levels. Thus, SAP is a modulator of PD-1 function and a potential biomarker for reduced responses to PD-1–based interventions.
Antagonistic regulation of trafficking to
Caenorhabditis elegans
sensory cilia by a
Retinal Degeneration 3
homolog and retromer
Authors: Martínez-Velázquez Luis A. , Ringstad Niels
Published: December 2017

Significance

Sensory neurons concentrate the molecular machinery of sensation into a specialized cellular antenna: the cilium. Proteins destined for the cilium are synthesized in the cell body, and poorly understood mechanisms separate them from other cellular proteins and target them to the cilium. Through genetic studies of this process in sensory neurons of the nematode
Caenorhabditis elegans
, we show that a sensory neuron-specific factor that mutates in humans to cause photoreceptor degeneration and blindness regulates an early stage in the trafficking of a key molecule for sensation.
Distinctive roles of age, sex, and genetics in shaping transcriptional variation of human immune responses to microbial challenges
Authors: Piasecka Barbara , Duffy Darragh , Urrutia Alejandra , Quach Hélène , Patin Etienne , Posseme Céline , Bergstedt Jacob , Charbit Bruno , Rouilly Vincent , MacPherson Cameron R. , Hasan Milena , Albaud Benoit , Gentien David , Fellay Jacques , Albert Matthew L. , Quintana-Murci Lluis ,   the Milieu Intérieur Consortium, Abel Laurent , Alcover Andres , Aschard Hugues , Aström Kalle , Bousso Philippe , Bruhns Pierre , Cumano Ana , Duffy Darragh , Demangel Caroline , Deriano Ludovic , Di Santo James , Dromer Françoise , Eberl Gérard , Enninga Jost , Fellay Jacques , Fontes Magnus , Freitas Antonio , Gelpi Odile , Gomperts-Boneca Ivo , Hercberg Serge , Lantz Olivier , Leclerc Claude , Mouquet Hugo , Patin Etienne , Pellegrini Sandra , Pol Stanislas , Raussel Antonio , Rogge Lars , Sakuntabhai Anavaj , Schwartz Olivier , Schwikowski Benno , Shorte Spencer , Soumelis Vassili , Tangy Frédéric , Tartour Eric , Toubert Antoine , Ungeheuer Marie-Noëlle , Quintana-Murci Lluis , Albert Matthew L.
Published: December 2017

Significance

Identifying the drivers of the interindividual diversity of the human immune system is crucial to understand their consequences on immune-mediated diseases. By examining the transcriptional responses of 1,000 individuals to various microbial challenges, we show that age and sex influence the expression of many immune-related genes, but their effects are overall moderate, whereas genetic factors affect a smaller gene set but with a stronger effect. We identify numerous genetic variants that affect transcriptional variation on infection, many of which are associated with autoimmune or inflammatory disorders. These results enable additional exploration of the role of regulatory variants in the pathogenesis of immune-related diseases and improve our understanding of the respective effects of age, sex, and genetics on immune response variation.
A mixed modality approach towards Xi reactivation for Rett syndrome and other X-linked disorders
Authors: Carrette Lieselot L. G. , Wang Chen-Yu , Wei Chunyao , Press William , Ma Weiyuan , Kelleher Raymond J. , Lee Jeannie T.
Published: December 2017

Significance

The X-chromosome harbors hundreds of disease genes, a subset of which gives rise to neurodevelopmental disorders such as Rett syndrome (RTT), fragile X syndrome, and CDKL5 syndrome. There is presently no disease-specific treatment. Here, we work toward a therapeutic program based on reactivation of the silent X chromosome to restore expression of the missing protein. We develop a mixed modality approach that combines a small-molecule inhibitor of DNA methylation and an antisense oligonucleotide against Xist RNA. This combination achieves up to 30,000-fold methyl-CpG binding protein 2 upregulation in cultured cells. In vivo modeling using a conditional
Xist
knockout and 5-aza-2′-deoxycytidine recapitulates inactive X reactivation. These findings provide proof of concept for the mixed modality approach to treat X-linked disorders, including RTT.
Iron balance and iron supplementation for the female athlete: A practical approach
Authors: Pedlar Charles R , Brugnara Carlo , Bruinvels Georgie , Burden Richard
Published: December 2017

Maintaining a positive iron balance is essential for female athletes to avoid the effects of iron deficiency and anaemia and to maintain or improve performance. A major function of iron is in the production of the oxygen and carbon dioxide carrying molecule, haemoglobin, via erythropoiesis. Iron balance is under the control of a number of factors including the peptide hormone hepcidin, dietary iron intake and absorption, environmental stressors (e.g. altitude), exercise, menstrual blood loss and genetics. Menstruating females, particularly those with heavy menstrual bleeding are at an elevated risk of iron deficiency. Haemoglobin concentration [Hb] and serum ferritin (sFer) are traditionally used to identify iron deficiency, however, in isolation these may have limited value in athletes due to: (1) the effects of fluctuations in plasma volume in response to training or the environment on [Hb], (2) the influence of inflammation on sFer and (3) the absence of sport, gender and individually specific normative data. A more detailed and longitudinal examination of haematology, menstrual cycle pattern, biochemistry, exercise physiology, environmental factors and training load can offer a superior characterisation of iron status and help to direct appropriate interventions that will avoid iron deficiency or iron overload. Supplementation is often required in iron deficiency; however, nutritional strategies to increase iron intake, rest and descent from altitude can also be effective and will help to prevent future iron deficient episodes. In severe cases or where there is a time‐critical need, such as major championships, iron injections may be appropriate.
ATP is stored in lamellar bodies to activate vesicular P2X4 in an autocrine fashion upon exocytosis
Authors: Fois Giorgio , Winkelmann Veronika Eva , Bareis Lara , Staudenmaier Laura , Hecht Elena , Ziller Charlotte , Ehinger Konstantin , Schymeinsky Jürgen , Kranz Christine , Frick Manfred
Published: December 2017

Vesicular P2X4 receptors are known to facilitate secretion and activation of pulmonary surfactant in the alveoli of the lungs. P2X4 receptors are expressed in the membrane of lamellar bodies (LBs), large secretory lysosomes that store lung surfactant in alveolar type II epithelial cells, and become inserted into the plasma membrane after exocytosis. Subsequent activation of P2X4 receptors by adenosine triphosphate (ATP) results in local fusion-activated cation entry (FACE), facilitating fusion pore dilation, surfactant secretion, and surfactant activation. Despite the importance of ATP in the alveoli, and hence lung function, the origin of ATP in the alveoli is still elusive. In this study, we demonstrate that ATP is stored within LBs themselves at a concentration of ∼1.9 mM. ATP is loaded into LBs by the vesicular nucleotide transporter but does not activate P2X4 receptors because of the low intraluminal pH (5.5). However, the rise in intravesicular pH after opening of the exocytic fusion pore results in immediate activation of vesicular P2X4 by vesicular ATP. Our data suggest a new model in which agonist (ATP) and receptor (P2X4) are located in the same intracellular compartment (LB), protected from premature degradation (ATP) and activation (P2X4), and ideally placed to ensure coordinated and timely receptor activation as soon as fusion occurs to facilitate surfactant secretion.
Gravin regulates centrosome function through PLK1
Authors: Colicino Erica G. , Garrastegui Alice M. , Freshour Judy , Santra Peu , Post Dawn E. , Kotula Leszek , Hehnly Heidi
Published: December 2017

We propose to understand how the mitotic kinase PLK1 drives chromosome segregation errors, with a specific focus on Gravin, a PLK1 scaffold. In both three-dimensional primary prostate cancer cell cultures that are prone to Gravin depletion and Gravin short hairpin RNA (shRNA)–treated cells, an increase in cells containing micronuclei was noted in comparison with controls. To examine whether the loss of Gravin affected PLK1 distribution and activity, we utilized photokinetics and a PLK1 activity biosensor. Gravin depletion resulted in an increased PLK1 mobile fraction, causing the redistribution of active PLK1, which leads to increased defocusing and phosphorylation of the mitotic centrosome protein CEP215 at serine-613. Gravin depletion further led to defects in microtubule renucleation from mitotic centrosomes, decreased kinetochore-fiber integrity, increased incidence of chromosome misalignment, and subsequent formation of micronuclei following mitosis completion. Murine Gravin rescued chromosome misalignment and micronuclei formation, but a mutant Gravin that cannot bind PLK1 did not. These findings suggest that disruption of a Gravin–PLK1 interface leads to inappropriate PLK1 activity contributing to chromosome segregation errors, formation of micronuclei, and subsequent DNA damage.
Aligning dynamic networks with DynaWAVE
Authors: Vijayan Vipin , Milenković Tijana
Published: December 2017

Motivation

Network alignment (NA) aims to find similar (conserved) regions between networks, such as cellular networks of different species. Until recently, existing methods were limited to aligning static networks. However, real-world systems, including cellular functioning, are dynamic. Hence, in our previous work, we introduced the first ever dynamic NA method, DynaMAGNA++, which improved upon the traditional static NA. However, DynaMAGNA++ does not necessarily scale well to larger networks in terms of alignment quality or runtime.

Results

To address this, we introduce a new dynamic NA approach, DynaWAVE. We show that DynaWAVE complements DynaMAGNA++: while DynaMAGNA++ is more accurate yet slower than DynaWAVE for smaller networks, DynaWAVE is both more accurate and faster than DynaMAGNA++ for larger networks. We provide a friendly user interface and source code for DynaWAVE.

Availability and implementation

https://www.nd.edu/∼cone/DynaWAVE/.

Supplementary information

Supplementary data are available at Bioinformatics online.
Alternaria malicola sp. nov., a New Pathogen Causing Fruit Spot on Apple in China
Authors: Dang J. L. , Gleason M. L. , Li L. N. , Wang C. , Niu C. K. , Zhang R. , Sun G. Y.
Published: December 2017

Alternaria spp. are pathogens of several diseases that pose significant threats to apple production. Several putative Alternaria sp. isolates were obtained from lesions of a disease commonly referred to as black dot on apple fruit in Shaanxi Province, China. Pathogenicity tests using mycelial plugs and conidial suspensions indicated that this isolate could cause leaf blotch, as well as moldy core and black dot on fruit. On the basis of sequence analysis of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RNA polymerase second largest subunit, and translation elongation factor 1-α, an isolate clustered with the Alternaria sect. Ulocladioides. By combining GAPDH, major allergen Alta1, mating type protein 1-2-1, and the AGA1 gene sequence analysis and morphological description, the isolates were identified as a new species named Alternaria malicola. Our finding expands the documented diversity of apple pathogens within the genus Alternaria and clarifies the taxonomy of the pathogen assemblage that may be associated with three apple diseases.
Nitrous oxide for labor analgesia
Authors: Hellams Audrey , Sprague Taylor , Saldanha Christina , Archambault Mark
Published: December 2017

Inhaled nitrous oxide (N2O) has been used worldwide for over 100 years as labor analgesia but has not gained widespread use in the United States. Nitrous oxide provides a noninvasive option for laboring women. This article outlines its efficacy and safety as an analgesic compared with epidural and IV pain medications.
Job openings for PAs by specialty
Authors: Morgan Perri , Leach Brandi , Himmerick Kristine , Everett Christine
Published: December 2017

Objective:

Physician assistants (PAs) have adapted to roles in virtually every practice specialty. One factor that has affected PAs' specialty choices has been the availability of jobs. We describe 2014 job postings for PAs at the national level by practice specialty.

Methods:

National data on 2014 job postings for PAs were obtained from a leading labor analytics firm. Each job posting (N = 34,137) was coded with regard to practice specialty and analyzed descriptively.

Results:

The largest proportions of job postings were in the surgical (28%) and medical subspecialty (23%) categories, followed by primary care (19%), other (18%), and emergency/urgent care (12%).

Conclusions:

Job opportunities for PAs are plentiful and are focused in subspecialty practice. Future research should examine trends in job postings for PAs. Trend analyses will be useful for multiple purposes, including informing PAs who are seeking employment and tracking demand for the profession as a whole.
Comparing Lumbar Disc Space Preparation With Fluoroscopy Versus Cone Beam-Computed Tomography and Navigation
Authors: Hurley Richard K. , Anderson Edward R. , Lawson Bryan K. , Hobbs Joseph K. , Aden James K. , Jorgensen Anton Y.
Published: December 2017

Study Design.

Cadaveric study.

Objective.

This cadaveric study sought to evaluate the efficacy of disc space preparation with cone beam-computed tomography with navigation (CBCT+N) for instrument placement compared with instrument placement with conventional fluoroscopy.

Summary of Background Data.

Disc space preparation from a transforaminal lumbar approach is challenging with respect to visualization, and surgeons currently rely on tactile feel and two-dimensional imaging in the operating room to assess instrument positioning.

Methods.

Two orthopedic spine surgeons performed 40 disc space preparations after eight cadavers were randomly assigned to fluoroscopy versus CBCT+N. Digital images of each vertebral endplate were captured and the percent disc removed by area for the total disc and by quadrants was determined using digital imaging software.

Results.

There were 20 lumbar disc levels prepared in the fluoroscopy group. There were 3 thoracolumbar, and 17 lumbar disc levels prepared in the experimental group. Percent disc removed relative to the total area of the disc, as determined by the digital imaging software, was higher in the CBCT+N group (P ≤ 0.0001). More disc was removed in both the anterior contralateral and posterior contralateral quadrants in the CBCT+N group (P = 0.0006 and P ≤ 0.0001 respectively). The intraclass correlation coefficient among blinded reviewers for percent disc removed was 0.759 (95% confidence interval, 0.587–0.866)]. There was no difference in time to complete disc space preparation, number of instrument passes, or number of endplate violations between the two groups (P = 0.28, P = 0.92, and P = 0.34 respectively).

Conclusion.

The results of this cadaveric investigation reveal that CBCT+N guidance may be used to assess instrument placement for interbody disc space preparation in a similar length of time, with no difference in instrument passes or endplate violations, in comparison with fluoroscopy.

Level of Evidence: 5
Diagnostic Benefits of Axial-Loaded Magnetic Resonance Imaging Over Recumbent Magnetic Resonance Imaging in Obese Lower Back Pain Patients
Authors: Lorenc Tomasz , Palczewski Piotr , Wójcik Damian , Glinkowski Wojciech , Gołębiowski Marek
Published: December 2017

Study Design.

Single center before-after case series study.

Objective.

To determine when and in which kind of lower back pathologies, axial-loaded magnetic resonance imaging (MRI) provides additional benefit over recumbent MRI.

Summary and Background Data.

Systems simulating physiological axial loading of the spine in patients examined in the supine position have recently been introduced in clinical practice. However, indications for examinations with axial loading have yet to be clearly specified.

Methods.

Ninety patients (46 men, 44 women, aged 20–90 yr) with lower back pain underwent lumbar spine MRI with and without axial loading. MRI was performed in a supine position on a 1.5 T system using a compression device. A high-resolution 3D T2-weighted sequence was used for image acquisition. Clinical characteristics of patients were established using questionnaire surveys and demographic data. MR images were assessed for the appearance of changes after axial loading. After determining which patients showed significant changes, logistic regression analysis was performed with 15 independent variables (clinical, demographic, and imaging-related).

Results.

After axial loading, 48.9% of patients showed additional changes. Multivariate analysis revealed that only obesity was a statistically significant predictor of the occurrence of changes (P < 0.05). After axial loading, 11 potentially clinically relevant changes appeared in seven patients, the most common being absolute spinal stenosis (n = 7).

Conclusion.

Axial loading may increase the diagnostic value of lumbar spine MRI in patients with obesity and/or those with suspected spinal canal stenosis.

Level of Evidence:

4
Preinjury Patient Characteristics and Postinjury Neurological Status Are Associated With Mortality Following Spinal Cord Injury
Authors: Casper David S. , Zmistowski Benjamin , Schroeder Gregory D. , McKenzie James C. , Mangan John , Vatson Jayanth , Hilibrand Alan S. , Vaccaro Alexander R. , Kepler Christopher K.
Published: December 2017

Study Design.

Retrospective cohort study.

Objectives.

This study investigates the association between spinal cord injuries (SCI) and post-injury mortality.

Summary of Background Data.

SCIs) are severe conditions treated in the acute trauma setting. Owing to neurological deficits, unstable spinal columns, and associated injuries, these patients often have complex inpatient hospitalizations with significant morbidity and mortality. It is assumed that a high rate of postinjury mortality would follow such severe injuries; however, the effect of SCI and its treatment on predictors of longevity remain largely unknown.

Methods.

Patients seen at a regional referral center for SCI were reviewed from a prospectively maintained database. Four hundred and twenty-six patients with SCI and varying degrees of injury between 2004 and 2009 were collected. Injury characteristics, including injury severity score, level of SCI, and type of SCI were retrieved. To determine independent predictors of 5-year mortality, a logistic regression using patient and injury characteristics at the time of presentation was performed.

Results.

Average age was 47.4 years (range: 14–95), and 74.5% (318/426) were male. Half of the cohort sustained low-energy mechanisms of injury (220/426; 52.4%). The 30-day, 90-day, 1-year, 2-year, and 5-year mortality rates in the SCI cohort were 6.6% (28/426), 9.2% (39/426), 12.0% (51/426), 15.0% (64/426), and 17.8%, respectively (76/426). Logistic regression demonstrated that increasing age (B = 1.06, P < 0.001), increasing ICU length-of-stay (B = 1.06; P = 0.002), decreased motor score at presentation (B = 0.98; P = 0.004), and lack of surgical intervention (B = 0.38; P < 0.001) were independent predictors of mortality at 5 years.

Conclusion.

There is substantial mortality associated with SCI. A significant proportion of the mortalities occurred acutely after injury. Mortality was associated with neurological deficit and severity of injury, as well as with preinjury patient characteristics. To combat this high rate of death, efforts are needed to address the concomitant disease processes associated with neurological deficits.

Level of Evidence: 3
Herpesviridae Infection: Prevention, Screening, and Management
Authors: SUBRAMANIAM AKILA , BRITT WILLIAM J.
Published: December 2017

Bacterial, viral, and parasitic pathogens add significant morbidity and even mortality to pregnancy—with adverse effects extending to both the gravida and the newborn. Three herpesviruses deserve considerable attention given the effects of perinatal infection on obstetric outcomes, specifically maternal and neonatal morbidity. In the following review, we will provide a description of cytomegalovirus, herpes simplex virus, and varicella zoster virus. For each viral pathogen, we will describe the epidemiology, natural history, screening and diagnosis modalities, treatments, and implications for antepartum care. Furthermore, we will highlight future directions of work in reducing the morbidities associated with these viral pathogens.