bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular structure of vapor-deposited amorphous selenium
Authors: Goldan A. H. , Li C. , Pennycook S. J. , Schneider J. , Blom A. , Zhao W.
Published: October 2016

The structure of amorphous selenium is clouded with much uncertainty and contradictory results regarding the dominance of polymeric chains versus monomer rings. The analysis of the diffraction radial distribution functions are inconclusive because of the similarities between the crystalline allotropes of selenium in terms of the coordination number, bond length, bond angle, and dihedral angle. Here, we took a much different approach and probed the molecular symmetry of the thermodynamically unstable amorphous state via analysis of structural phase transformations. We verified the structure of the converted metastable and stable crystalline structures using scanning transmission electron microscopy. In addition, given that no experimental technique can tell us the exact three-dimensional atomic arrangements in glassy semiconductors, we performed molecular-dynamic simulations using a well-established empirical three-body interatomic potential. We developed a true vapor-deposited process for the deposition of selenium molecules onto a substrate using empirical molecular vapor compositions and densities. We prepared both vapor-deposited and melt-quenched samples and showed that the simulated radial distribution functions match very well to experiment. The combination of our experimental and molecular-dynamic analyses shows that the structures of vapor- and melt-quenched glassy/amorphous selenium are quite different, based primarily on rings and chains, respectively, reflecting the predominant structure of the parent phase in its thermodynamic equilibrium.
The progress in development of edge tangential Thomson scattering system on HL-2A tokamak
Authors: Liu C. H. , Huang Y. , Wang Y. Q. , Feng Z. , Hou Z. P. , Fu B. Z.
Published: October 2016

The edge tangential Thomson scattering system (ETTSS) was developed for the first time on a HL-2A tokamak. A Nd:YAG laser with a 1064 nm wavelength, 4 J energy, and 30 Hz repetition rate is employed on the ETTSS. The laser beam injects the plasma in the tangential direction on the mid-plane of the machine, and the angles between the laser injection direction and the scattered light collection direction are in the range from 157.5° to 162.8°. The scattered light collection optics with 0.21-0.47 magnification is utilized to collect the scattered light of measurement range from R = 1900 mm to 2100 mm (the normalized radius is from r/a = 0.625 to 1.125). Spatial resolution of the preliminary design could be up to Δr/a = 0.016. The measurement requirements could be achieved: 10 eV < Te < 1.5 keV, and 0.5 × 1019 m−3 < ne < 3 × 1019 m−3 with errors less than 15% and 10%, respectively.
Eight-channel Kirkpatrick–Baez microscope for multiframe x-ray imaging diagnostics in laser plasma experiments
Authors: Yi Shengzhen , Zhang Zhe , Huang Qiushi , Zhang Zhong , Mu Baozhong , Wang Zhanshan , Fang Zhiheng , Wang Wei , Fu Sizu
Published: October 2016

Because grazing–incidence Kirkpatrick–Baez (KB) microscopes have better resolution and collection efficiency than pinhole cameras, they have been widely used for x-ray imaging diagnostics of laser inertial confinement fusion. The assembly and adjustment of a multichannel KB microscope must meet stringent requirements for image resolution and reproducible alignment. In the present study, an eight-channel KB microscope was developed for diagnostics by imaging self-emission x-rays with a framing camera at the Shenguang-II Update (SGII-Update) laser facility. A consistent object field of view is ensured in the eight channels using an assembly method based on conical reference cones, which also allow the intervals between the eight images to be tuned to couple with the microstrips of the x-ray framing camera. The eight-channel KB microscope was adjusted via real-time x-ray imaging experiments in the laboratory. This paper describes the details of the eight-channel KB microscope, its optical and multilayer design, the assembly and alignment methods, and results of imaging in the laboratory and at the SGII-Update.
Effect of metal oxide additions to quality on Ge/GeO2 interfaces
Authors: Li Hongfei , Robertson John , Okuno Yasutoshi
Published: October 2016

Alloying amorphous GeO2 with Y2O3 or related group IIIA oxides is known experimentally to improve its properties as a gate dielectric in field effect transistors. The mechanism of this is studied here by density functional calculations. The metal site coordination is found to be 6–7, by increasing the oxygen coordination to 3 or higher. The alloying is found to increase the bulk modulus. Alloying also increases the diffusion energy of the oxygen vacancies in GeO2 next to the metal and also increases the vacancy formation energy of oxygens that are second neighbors of the metal sites. In this way, a relatively small metal concentration can reduce the O vacancy diffusion rate and thereby the GeO evolution rate. Oxygen vacancies at the Ge/GeO2 interface next to a metal site are found to divide into two types, those which rebond across the vacancy (La, Hf) and those without rebonding (Y, Sc, Al), the latter being preferable as they do not give rise to interfacial gap states.
Head-on collision of two dust ion acoustic solitary waves in a weakly relativistic multicomponent superthermal plasma
Authors: Saini N. S. , Singh Kuldeep
Published: October 2016

A head-on collision between two dust ion acoustic solitary waves (DIASWs) travelling in the opposite direction in a weakly relativistic plasma composed of four distinct particle populations, namely, weakly relativistic ion fluid, superthermal electrons as well as positrons, and immobile dust, is investigated. By employing extended Poincaré-Lighthill-Kuo method, two Korteweg-de Vries (KdV) equations are derived. The analytical phase shift after a head-on collision of two dust ion acoustic (DIA) solitary waves is also obtained. The combined effects of relativistic factor (β), electron to positron temperature ratio (α), ion to electron temperature ratio (σ), positron to electron density ratio (P), dust density ratio (d), and superthermality of electrons as well as positrons (via κ) on the phase shifts are numerically studied. All these physical parameters have also changed the potential amplitude and the width of colliding solitary waves. It is found that the presence of superthermal electrons as well as positrons and dust grains has emphatic influence on the phase shifts and potential pulse profiles of compressive DIA solitons. Our results are general and may be helpful in understanding a head-on collision between two DIASWs in astrophysical and laboratory plasmas, especially the interaction of pulsar relativistic winds with supernova ejecta that produces the superthermal particles and relativistic ions.
The Cassie-Wenzel transition of fluids on nanostructured substrates: Macroscopic force balance versus microscopic density-functional theory
Authors: Tretyakov Nikita , Papadopoulos Periklis , Vollmer Doris , Butt Hans-Jürgen , Dünweg Burkhard , Daoulas Kostas Ch.
Published: October 2016

Classical density functional theory is applied to investigate the validity of a phenomenological force-balance description of the stability of the Cassie state of liquids on substrates with nanoscale corrugation. A bulk free-energy functional of third order in local density is combined with a square-gradient term, describing the liquid-vapor interface. The bulk free energy is parameterized to reproduce the liquid density and the compressibility of water. The square-gradient term is adjusted to model the width of the water-vapor interface. The substrate is modeled by an external potential, based upon the Lennard-Jones interactions. The three-dimensional calculation focuses on substrates patterned with nanostripes and square-shaped nanopillars. Using both the force-balance relation and density-functional theory, we locate the Cassie-to-Wenzel transition as a function of the corrugation parameters. We demonstrate that the force-balance relation gives a qualitatively reasonable description of the transition even on the nanoscale. The force balance utilizes an effective contact angle between the fluid and the vertical wall of the corrugation to parameterize the impalement pressure. This effective angle is found to have values smaller than the Young contact angle. This observation corresponds to an impalement pressure that is smaller than the value predicted by macroscopic theory. Therefore, this effective angle embodies effects specific to nanoscopically corrugated surfaces, including the finite range of the liquid-solid potential (which has both repulsive and attractive parts), line tension, and the finite interface thickness. Consistently with this picture, both patterns (stripes and pillars) yield the same effective contact angles for large periods of corrugation.
High repetition-rate neutron generation by several-mJ, 35 fs pulses interacting with free-flowing D2O
Authors: Hah J. , Petrov G. M. , Nees J. A. , He Z.-H. , Hammig M. D. , Krushelnick K. , Thomas A. G. R.
Published: October 2016

Using several-mJ energy pulses from a high-repetition rate (1/2 kHz), ultrashort (35 fs) pulsed laser interacting with a ∼10 μm diameter stream of free-flowing heavy water (D2O), we demonstrate a 2.45 MeV neutron flux of 105/s. Operating at high intensity (of order 1019 W/cm2), laser pulse energy is efficiently absorbed in the pre-plasma, generating energetic deuterons. These collide with deuterium nuclei in both the bulk target and the large volume of low density D2O vapor surrounding the target to generate neutrons through d(d,n)3He reactions. The neutron flux, as measured by a calibrated neutron bubble detector, increases as the laser pulse energy is increased from 6 mJ to 12 mJ. A quantitative comparison between the measured flux and the results derived from 2D-particle-in-cell simulations shows comparable neutron fluxes for laser characteristics similar to the experiment. The simulations reveal that there are two groups of deuterons. Forward moving deuterons generate deuterium–deuterium fusion reactions in the D2O stream and act as a point source of neutrons, while backward moving deuterons propagate through the low-density D2O vapor filled chamber and yield a volumetric source of neutrons.
Combining complementary multiple bandgaps in one-dimensional plasma photonic crystal heterostructures
Authors: Zhang Juan , Zou Junhui , Wang Yang
Published: October 2016

A single bandgap overlapping scheme is often used to enlarge the photonic bandgap (PBG) range in cascaded or hetero one-dimensional photonic crystal (1D PC) structures. In this paper, we design an optimized one-dimensional plasma photonic crystal (1D PPC) heterostructure based on the idea of combining complementary multiple PBGs to enlarge the PBG range. The flexibility of the PBG of a 1D PPC, caused by the frequency-dependent dispersive properties of plasma, is helpful for generating and combining multiple bandgaps. The obtained omni-directional photonic bandgap (ODPBG) width for the 1D PPC heterostructure is dramatically enhanced compared with that of a single 1D PPC alone and is much larger than that of 1D PC heterostructures described in the previous works. Further study shows that the PPC heterostructures are more suitable than other heterostructures (such as a 1D PC heterostructure or heterostructures composed of a 1D PPC and 1D PC) for combining complementary PBGs. The ODPBG ranges for 1D PPC heterostructures can be further extended by adjusting the parameters of the plasma to allow more complementary PBGs to combine with each other.
Interfacial waves generated by electrowetting-driven contact line motion
Authors: Ha Jonghyun , Park Jaebum , Kim Yunhee , Shin Bongsu , Bae Jungmok , Kim Ho-Young
Published: October 2016

The contact angle of a liquid-fluid interface can be effectively modulated by the electrowetting-on-dielectric (EWOD) technology. Rapid movement of the contact line can be achieved by swift changes of voltage at the electrodes, which can give rise to interfacial waves under the strong influence of surface tension. Here we experimentally demonstrate EWOD-driven interfacial waves of overlapping liquids and compare their wavelength and decay length with the theoretical results obtained by a perturbation analysis. Our theory also allows us to predict the temporal evolution of the interfacial profiles in either rectangular or cylindrical containers, as driven by slipping contact lines. This work builds a theoretical framework to understand and predict the dynamics of capillary waves of a liquid-liquid interface driven by EWOD, which has practical implications on optofluidic devices used to guide light.
Enhancing charge-density-wave order in 1T-TiSe2 nanosheet by encapsulation with hexagonal boron nitride
Authors: Li L. J. , Zhao W. J. , Liu B. , Ren T. H. , Eda G. , Loh K. P.
Published: October 2016

Layered transition metal dichalcogenides (TMDs) provide an ideal platform for exploring the effects of dimensionality on correlated electronic phases such as charge density wave (CDW) order. When TMDs are reduced in thickness to the 2-D limit, it is expected that the substrates will exert a considerable influence on the electron states. Here, we report a study of the charge density wave state in 1T-TiSe2 nanosheets of different thicknesses when the sheets are encapsulated by hexagonal Boron Nitride or supported on the SiO2 substrate. Our results show that dimensionality reduction results in an enhancement of CDW order and that disorder and substrate phonons tend to destroy CDW order, preventing observation of intrinsic CDW transition in ultrathin samples. Encapsulated 10 nm thick 1T-TiSe2 samples exhibit intrinsic CDW with transition temperature as high as 235 K. Our study points out that choosing the right substrate is important in the search for room temperature CDW materials.
Anomalous rectification in a purely electronic memristor
Authors: Wang Jingrui , Pan Ruobing , Cao Hongtao , Wang Yang , Liang Lingyan , Zhang Hongliang , Gao Junhua , Zhuge Fei
Published: October 2016

An anomalous rectification was observed in a purely electronic memristive device Ti/ZnO/Pt. It could be due to (1) an Ohmic or quasi-Ohmic contact at the ZnO/Pt interface and (2) a Schottky contact at the Ti/ZnO interface. The Ohmic contact originates from the reduction of ZnO occurring in the whole film instead of only at the Ti/ZnO interface. The Schottky contact may come from moisture adsorbed in the nanoporous ZnO. The conduction in the electroformed device is controlled by the carrier trapping/detrapping of the trap sites, inducing a poor rectification and high nonlinearity. Furthermore, a complementary resistive switching was achieved.
Patch antenna microcavity terahertz sources with enhanced emission
Authors: Madéo J. , Todorov Y. , Gilman A. , Frucci G. , Li L. H. , Davies A. G. , Linfield E. H. , Sirtori C. , Dani K. M.
Published: October 2016

We study the emission properties of an electroluminescent THz frequency quantum cascade structure embedded in an array of patch antenna double-metal microcavities. We show that high photon extraction efficiencies can be obtained by adjusting the active region thickness and array periodicity as well as high Purcell factors (up to 65), leading to an enhanced overall emitted power. Up to a 44-fold increase in power is experimentally observed in comparison with a reference device processed in conventional mesa geometry. Estimation of the Purcell factors using electromagnetic simulations and the theoretical extraction efficiency are in agreement with the observed power enhancement and show that, in these microcavities, the overall enhancement solely depends on the square of the total quality factor.
Two-way actuation of graphene oxide arising from quantum mechanical effects
Authors: Chang Zhenyue , Deng Junkai , Chandrakumara Ganaka G. , Yan Wenyi , Liu Jefferson Zhe
Published: October 2016

Using density functional theory (DFT) calculations, two stable phases were found for several graphene oxide (GO) crystals with linearly aligned epoxy groups. Upon electron injection, they exhibit two-way actuation behavior. This two-way actuation is named by the observations that one piece of monolayer GO crystal is able to expand or contract upon electron injection, namely, contraction of the stable phase, and expansion of the meta-stable phase. The obtained maximum in-plane strains are as high as 8% and −5%. Such large deformation in opposite directions obtained from a single piece GO material offers unique opportunities in designing highly tunable and integrated actuators for microelectromechanical or nanoelectromechanical systems.
Thickness tunable transport in alloyed WSSe field effect transistors
Authors: Karande Shruti D. , Kaushik Naveen , Narang Deepa S. , Late Dattatray , Lodha Saurabh
Published: October 2016

We report the field effect transistor characteristics of exfoliated transition metal dichalcogenide alloy tungsten sulphoselenide. WSSe is a layered material of strongly bonded S-W-Se atoms having weak interlayer van der Waals forces with a significant potential for spintronic and valleytronic applications due to its polar nature. The X-ray photoelectron spectroscopy measurements on crystals grown by the chemical vapor transport method indicate a stoichiometry of the form WSSe. We report flake thickness tunable transport mechanism with n-type behavior in thin flakes (≤11 nm) and ambipolarity in thicker flakes. The devices with flake thicknesses of 2.4 nm–54.8 nm exhibit a maximum electron mobility of ∼50 cm2/V s along with an ION/IOFF ratio >106. The electron Schottky barrier height values of 35 meV and 52 meV extracted from low temperature I–V measurements for 3.9 nm and 25.5 nm thick flakes, respectively, indicate that an increase in hole current with thickness is likely due to lowering of the bandgap through an increase in energy of the valence band maximum.
Rheology behaviors of stable electrohydrodynamic direct-write jet
Authors: Wang Xiang , Zheng Gaofeng , Xu Lei , Wang Han , Li Wenwang
Published: October 2016

Electrohydrodynamic direct-write (EDW) is a novel direct-write technology to fabricate micro/nano-structures from viscoelastic solution, which had displayed great application potential in organic electronic device. Due to the shorter spinneret to substrate distance, the rheology behaviors of EDW charged jet played an important role in defining the line width or diameter of the direct-written micro/nano-structures. High speed camera is utilized to observe the rheology process of EDW charged jet, and solidified jets are measured by SEM that offers a quantitative method to investigate the diameter evolution of jet. The diameter of charged jet and nanofiber injected from solid probe increase with the increasing of polymer solution concentration. Attribute to the larger diameter and higher solvent content, charged jet injected from hollow nozzle displayed greater fluid viscoelasticity, and then stretched into micro structure of flat film under the gravitation on the substrate. The diameter of charged jet and line width of thin film injected from nozzle decrease with the increasing of polymer concentration.
Solid-state NMR resolves protein structures—no deuteration required
Authors: Miller Johanna L.
Published: October 2016

Spinning the samples at extraordinarily high frequency is key to untangling the biomolecules’ complicated spectra.
Mint3 potentiates TLR3/4- and RIG-I–induced IFN-β expression and antiviral immune responses
Authors: Huai Wanwan , Song Hui , Yu Zhongxia , Wang Wenwen , Han Lihui , Sakamoto Takeharu , Seiki Motoharu , Zhang Lining , Zhang Qunye , Zhao Wei
Published: October 2016

Significance

Optimal productions of type I IFNs are crucial for maintaining immune homeostasis and elimination of invading viruses. A couple of enhancers of host antiviral innate immunity are induced following vial infection and then potentiate type I IFN production. Here, we identified munc18-1–interacting protein 3 (Mint3) as a viral infection-induced physiological enhancer of antiviral immune responses. Viral infection and IFN-β secretion induced Mint3 expression in the virus-infected cells, and Mint3 then feedback-promoted Toll-like recptor- and retinoic acid-inducible gene-I–induced IFN-β expression. These results will be valuable for understanding the crosstalk between virus and host immune systems. Furthermore, as IFN-β has manifested in diverse pathogenic autoimmune diseases, control of IFN-β production via suppressing Mint3 will be a potential target for designing therapeutic strategies against autoimmune disorders.
StimulatingS-adenosyl-l-methionine synthesis extends lifespan via activation of AMPK
Authors: Ogawa Takafumi , Tsubakiyama Ryohei , Kanai Muneyoshi , Koyama Tetsuya , Fujii Tsutomu , Iefuji Haruyuki , Soga Tomoyoshi , Kume Kazunori , Miyakawa Tokichi , Hirata Dai , Mizunuma Masaki
Published: October 2016

Significance

Calorie restriction (CR) or methionine (Met) restriction extends the lifespan of diverse model organisms. Here we carefully examined how Met metabolites influenced aging in yeast. We showed that stimulatingS-adenosyl-l-methionine (AdoMet) synthesis, which consumes both ATP and Met, resulted in an extended lifespan and was epistatic to CR. Indeed, stimulating AdoMet synthesis led to AMP-activated protein kinase activation and increased lifespan. Furthermore, we revealed an effect ofS-adenosyl-l-homocysteine that contributed to longevity with a higher accumulation of AdoMet. The most common CR regimen involves reducing caloric intake, an unpopular trade-off. We have shown that stimulating AdoMet synthesis per se in yeast could produce physiological conditions that mimicked CR.
Epstein–Barr virus microRNAs reduce immune surveillance by virus-specific CD8
+
T cells
Authors: Albanese Manuel , Tagawa Takanobu , Bouvet Mickaël , Maliqi Liridona , Lutter Dominik , Hoser Jonathan , Hastreiter Maximilian , Hayes Mitch , Sugden Bill , Martin Larissa , Moosmann Andreas , Hammerschmidt Wolfgang
Published: October 2016

Significance

Most humans are infected for their lifetime with Epstein–Barr virus (EBV), which can cause cancer and other EBV-associated diseases. Infected individuals develop strong immune responses to this virus, in particular cytotoxic CD8
+
T cells, but viral infection is never cleared nor is EBV eliminated from the body. This suggests that certain viral molecules might prevent effective elimination of EBV-infected cells by CD8
+
T cells. EBV is rich in genes coding for microRNAs, many with unknown function. We show that viral microRNAs interfere with recognition and killing of EBV-infected cells by CD8
+
T cells. Multiple mechanisms and molecules are targeted by microRNAs to achieve this immune evasion. Therefore, targeting of viral microRNAs may improve antiviral immunity and therapy.
Simplified derivation of the gravitational wave stress tensor from the linearized Einstein field equations
Authors: Balbus Steven A.
Published: October 2016

Significance

Gravitational radiation provides a probe of unprecedented power with which to elucidate important astrophysical processes that are otherwise completely dark (e.g., black hole mergers) or impenetrable (e.g., supernova and early universe dynamics). Historically, the gap between propagating fluctuations in the spacetime metric and classical dynamical concepts such as energy and angular momentum conservation has bedeviled this subject. By now, there is a vast literature on this topic, and there are many powerful methods available. Because of their mathematical sophistication, however, they are not used in introductory texts, which are forced instead to a follow a much more cumbersome path. We present here a derivation of the most widely used form of the stress energy tensor of gravitational radiation, using elementary methods only.
Diagnostic Accuracy of the Inferior Vena Cava Collapsibility to Predict Fluid Responsiveness in Spontaneously Breathing Patients With Sepsis and Acute Circulatory Failure
Authors: Preau Sebastien , Bortolotti Perrine , Colling Delphine , Dewavrin Florent , Colas Vincent , Voisin Benoit , Onimus Thierry , Drumez Elodie , Durocher Alain , Redheuil Alban , Saulnier Fabienne
Published: October 2016

Objective:

To investigate whether the collapsibility index of the inferior vena cava recorded during a deep standardized inspiration predicts fluid responsiveness in nonintubated patients.

Design:

Prospective, nonrandomized study.

Setting:

ICUs at a general and a university hospital.

Patients:

Nonintubated patients without mechanical ventilation (n = 90) presenting with sepsis-induced acute circulatory failure and considered for volume expansion.

Interventions:

We assessed hemodynamic status at baseline and after a volume expansion induced by a 30-minute infusion of 500-mL gelatin 4%.

Measurements and Main Results:

We measured stroke volume index and collapsibility index of the inferior vena cava under a deep standardized inspiration using transthoracic echocardiography. Vena cava pertinent diameters were measured 15–20 mm caudal to the hepatic vein junction and recorded by bidimensional imaging on a subcostal long-axis view. Standardized respiratory cycles consisted of a deep standardized inspiration followed by passive exhalation. The collapsibility index expressed in percentage equaled the ratio of the difference between end-expiratory and minimum-inspiratory diameter over the end-expiratory diameter. After volume expansion, a relevant (≥ 10%) stroke volume index increase was recorded in 56% patients. In receiver operating characteristic analysis, the area under curve for that collapsibility index was 0.89 (95% CI, 0.82–0.97). When such index is superior or equal to 48%, fluid responsiveness is predicted with a sensitivity of 84% and a specificity of 90%.

Conclusions:

The collapsibility index of the inferior vena cava during a deep standardized inspiration is a simple, noninvasive bedside predictor of fluid responsiveness in nonintubated patients with sepsis-related acute circulatory failure.
Longitudinal analysis of changes in weight and waist circumference in relation to incident vasomotor symptoms: the Study of Women's Health Across the Nation (SWAN)
Authors: Gold Ellen B. , Crawford Sybil L. , Shelton Janie F. , Tepper Ping G. , Crandall Carolyn J. , Greendale Gail A. , Matthews Karen A. , Thurston Rebecca C. , Avis Nancy E.
Published: October 2016

Objective:

Greater body mass index (BMI) and body fat are associated with vasomotor symptoms (VMS). Thus, weight loss may prevent VMS. We analyzed whether concurrent BMI or waist circumference and/or changes in weight or waist circumference predicted incident VMS and whether these relations differed by menopause stage or race/ethnicity.

Methods:

Data from 10 follow-up visits for 1,546 participants in the Study of Women's Health Across the Nation who reported no VMS at baseline were modeled for time to first symptomatic visit in relation to concurrent BMI and waist circumference and change in weight and waist circumference during early and late menopause using discrete survival analyses, adjusting for covariates.

Results:

Greater concurrent BMI and waist circumference were significantly related to greater any and frequent (≥6 d in the last 2 wk) incident VMS in early menopause and lower VMS risk in late menopause. Percentage weight change since baseline and since the prior visit was unrelated to incident any VMS in either menopause stage. Percentage weight change since baseline had a significant shallow U-shaped association with incident frequent VMS in early menopause (P = 0.02), a shallow inverse U-shape in late menopause (P = 0.02), and a significant interaction with menopause stage (P = 0.004) but not with race/ethnicity. Recent weight change was unassociated with incident VMS in either menopause stage. Results were similar for waist change.

Conclusions:

Concurrent BMI and waist circumference were positively related to incident VMS in early menopause and negatively related in late menopause. Maintaining healthy weight in early menopause may help prevent VMS.
Evaluation of the Effect of Cycloplegia on Anterior Chamber Depth in Cataract Patients Using Optical Low-Coherence Reflectometry
Authors: Avdagic Ema , Lazzaro Douglas R.
Published: October 2016

Purpose:

The study was performed to study the effect of cycloplegia on anterior chamber depth (ACD) in cataract eyes. One instrument (Lenstar) was used for all measurements.

Methods:

Anterior chamber depth calculations were taken with the Lenstar in cataract eyes with a mean age of 71.9±8.8 years before instilling cycloplegic drops. Two drops of Tropicamide were then instilled in each eye and measurements were retaken between 30 to 45 min later.

Results:

Cycloplegia with a mild agent used routinely in this practice location showed a statically significant effect on increasing ACD by 0.0647±0.01 in the OD and 0.0758±0.02 in the OS.

Conclusions:

Anterior chamber depth can be important in the final refractive result postcataract surgery. The results of a change in effective lens position would be most significant in higher intraocular lens powers.
A Grounded Theory Qualitative Analysis of Interprofessional Providers' Perceptions on Caring for Critically Ill Infants and Children in Pediatric and General Emergency Departments
Authors: Gangadharan Sandeep , Tiyyagura Gunjan , Gawel Marcie , Walsh Barbara M. , Brown Linda L. , Lavoie Megan , Tay Khoon-Yen , Auerbach Marc A.
Published: October 2016

Objective

The objective of this study was to explore pediatric emergency department (PED) and general emergency department (GED) providers' perceptions on caring for critically ill infants and children.

Methods

This study utilized qualitative methods to examine the perceptions of emergency department providers caring for critically ill infants and children. Teams of providers participated in 4 in situ simulation cases followed by facilitated debriefings. Debriefings were recorded and professionally transcribed. The transcripts were reviewed independently and followed by group coding discussions to identify emerging themes. Consistent with grounded theory, the team iteratively revised the debriefing script as new understanding was gained. A total of 188 simulation debriefings were recorded in 24 departments, with 15 teams participating from 8 PEDs and 32 teams from 16 GEDs.

Results

Twenty-four debriefings were audiotaped and professionally transcribed verbatim. Thematic saturation was achieved after 20 transcripts. In our iterative qualitative analysis of these transcripts, we observed 4 themes: (1) GED provider comfort with algorithm-based pediatric care and overall comfort with pediatric care in PED, (2) GED provider reliance on cognitive aids versus experience-based recall by PED providers, (3) GED provider discomfort with locating and determining size or dose of pediatric-specific equipment and medications, and (4) PED provider reliance on larger team size and challenges with multitasking during resuscitation.

Conclusions

Our qualitative analysis produced several themes that help us to understand providers' perceptions in caring for critically ill children in GEDs and PEDs. These data could guide the development of targeted educational and improvement interventions.
Craniectomy and Traumatic Brain Injury in Children on Extracorporeal Membrane Oxygenation Support
Authors: Anton-Martin Pilar , Braga Bruno , Megison Stephen , Journeycake Janna , Moreland Jessica
Published: October 2016

Severe trauma may cause refractory life-threatening respiratory failure requiring extracorporeal membrane oxygenation (ECMO). Concurrent traumatic brain injury, however, complicates the use of ECMO because of the major risk of intracranial bleeding with systemic anticoagulation. Craniotomy and/or craniectomy for hematoma evacuation during ECMO are extremely high-risk procedures secondary to ongoing anticoagulation, and there are only a few such case reports in the literature. We present the case of a child with multiple thoracic injuries and life-threatening respiratory failure supported on ECMO. She developed an intracranial hemorrhage while systemically heparinized that required emergent decannulation and bedside craniectomy for hematoma extraction. She survived with an excellent neurologic outcome. We also review the relevant literature regarding the use of ECMO in patients with polytrauma and the occurrence of craniectomy on extracorporeal support, with a focus on pediatric publications. Patients with polytrauma with brain injury can be supported on ECMO, but extreme precaution must be taken regarding anticoagulation. The intracranial complications of ECMO in this population are not infrequent, but our case report and review of the literature suggest that neurosurgical intervention should be considered in life-threatening conditions when no other alternatives are available.
Quantification of Chronic Oxaliplatin-Induced Hypesthesia in Two Areas of the Hand
Authors: Andriamamonjy Mihary , Delmotte Jean-Baptiste , Savinelli Francesco , Beaussier Hélène , Coudoré François
Published: October 2016

Purpose:

Oxaliplatin is a platinum derivate widely used in cancer treatment but producing dose-limiting peripheral neurotoxicity. Acute neuropathy is characterized by a transient cold-induced distal allodynia, whereas chronic neuropathy leads to sensory loss. To design a method for quantitative assessment of oxaliplatin-induced peripheral neuropathy, we developed a study that aims to characterize the most appropriate skin area of the hand to perform sensory tests.

Methods:

We included patients treated for at least 6 months with oxaliplatin. Thermal sensory tests are assessed using the Thermotest (Somedic) and consist in measuring thermal thresholds in the thenar and in the fingertips of the opposite hand. Results are analyzed using T-Tests comparing thermal sensory thresholds between the two areas of the hand, globally and then individually.

Results:

In 7 weeks, 12 patients (7 men and 5 women; mean age: 64.5 years) were included, all treated with FOLFOX protocol. Thermal detection thresholds measured on the fingertips are 146% and 108% greater than the ones measured on the palm for cold and warm, respectively (P < 0.0001). Thermal pain thresholds are difficult to interpret. Regarding individual tests, 9/12 patients and 8/12 patients experienced hypesthesia to cold and warm, respectively.

Conclusions:

These results reveal that distal hypesthesia occurring under treatment with oxaliplatin is markedly pronounced in the fingertips; however, as thermal threshold is unknown before treatment, it is difficult to assert that fingertip thermal hypesthesia has developed under treatment. Finally, this short study may be useful to design a method for quantifying oxaliplatin-induced neuropathy.
Invariance principle and model reduction for the Fokker–Planck equation
Authors: Karlin I. V.
Published: October 2016

The principle of dynamic invariance is applied to obtain closed moment equations from the Fokker–Planck kinetic equation. The analysis is carried out to explicit formulae for computation of the lowest eigenvalue and of the corresponding eigenfunction for arbitrary potentials.

This article is part of the themed issue ‘Multiscale modelling at the physics–chemistry–biology interface’.
Mitochondrial DNA Density Homeostasis Accounts for the Threshold Effect in Human Mitochondrial Disease
Authors: Aryaman Juvid , Johnston Iain G. , Jones Nick S.
Published: October 2016

Mitochondrial dysfunction is involved in a wide array of devastating diseases but the heterogeneity and complexity of these diseases’ symptoms challenges theoretical understanding of their causation. With the explosion of -omics data, we have the unprecedented ability to gain deep understanding of the biochemical mechanisms of mitochondrial dysfunction. However, there is also a need to make such datasets interpretable, and quantitative modelling allows us to translate such datasets into intuition and suggest rational biomedical treatments. Working towards this interdisciplinary goal, we use a recently published large-scale dataset, and develop a mathematical model of progressive increase in mutant load of the MELAS 3243A>G mtDNA mutation to develop a descriptive and predictive biophysical model. The experimentally observed behaviour is surprisingly rich, but we find that a simple, biophysically-motivated model intuitively accounts for this heterogeneity and yields a wealth of biological predictions. Our findings suggest that cells attempt to maintain wild-type mtDNA density through cell volume reduction, and thus energy demand reduction, until a minimum cell volume is reached. Thereafter, cells toggle from demand reduction to supply increase, upregulating energy production pathways. Our analysis provides further evidence for the physiological significance of mtDNA density, and emphasizes the need for performing single-cell volume measurements jointly with mtDNA quantification. We propose novel experiments to verify the hypotheses made here, to further develop our understanding of the threshold effect, and connect with rational choices for mtDNA disease therapies.

Author Summary

Mitochondria are organelles which produce the major energy currency of the cell: ATP. Mitochondrial dysfunction is associated with a multitude of devastating diseases, from Parkinson’s disease to cancer. Large volumes of data related to these diseases are being produced, but translation of these data into rational biomedical treatment is challenged by a lack of theoretical understanding. We develop a mathematical model of progressive increase of mutant load in mitochondrial DNA, for the mutation associated with MELAS (the most common mitochondrial disease), to address this. We predict that cells attempt to maintain the ratio of healthy mtDNA to cell volume by reducing their cell volume until they reach a minimum cell volume. As mutant load continues to increase, cells switch strategy by increasing their energy supply pathways. Our work accounts for large-scale experimental data and makes testable predictions about mitochondrial dysfunction. It also provides support for increasing mitochondrial content, as well as reduction in dependence upon mitochondrial metabolism via the ketogenic diet, as relevant treatments for mitochondrial disease.
A network of topographic numerosity maps in human association cortex
Authors: Harvey Ben M , Dumoulin Serge O
Published: October 2016

Sensory and motor cortices each contain multiple topographic maps with the structure of sensory organs (such as the retina or cochlea) mapped onto the cortical surface. These sensory maps are hierarchically organized. For example, visual field maps contain neurons that represent increasing large parts of visual space with increasingly complex responses. Some visual neurons respond to stimuli with a particular numerosity, the number of objects in a set. We recently discovered a parietal topographic numerosity map where neural numerosity preferences progress gradually across the cortical surface, analogous to sensory maps. Following this analogy, we hypothesised that there may be multiple numerosity maps. Numerosity perception is implicated in many cognitive functions including foraging, multiple object tracking, dividing attention, decision making and mathematics. Here we use ultra-high-field (7T) fMRI and neural model-based analyses to reveal numerosity-selective neural populations organized into six widely separated topographic maps in each hemisphere. Although we describe subtle differences between these maps, their properties are very similar, unlike in sensory map hierarchies. These maps are found in areas implicated in object recognition, motion perception, attention control, decision-making and mathematics. Multiple numerosity maps may allow interactions with these many cognitive systems, suggesting a broad role for quantity processing in supporting many perceptual and cognitive functions.
A bacterial size law revealed by a coarse-grained model of cell physiology
Authors: Bertaux François , von Kügelgen Julius , Marguerat Samuel , Shahrezaei Vahid
Published: October 2016

Universal observations in Biology are sometimes described as “laws”. InE. coli, experimental studies performed over the past six decades have revealed major growth laws relating ribosomal mass fraction and cell size to the growth rate. Because they formalize complex emerging principles in biology, growth laws have been instrumental in shaping our understanding of bacterial physiology. Here, we discovered a novel size law that connects cell size to the inverse of the metabolic proteome mass fraction and the active fraction of ribosomes. We used a simple whole-cell coarse-grained model of cell physiology that combines the proteome allocation theory and the structural model of cell division. The model captures all available experimental data connecting the cell proteome composition, ribosome activity, division size and growth rate in response to nutrient quality, antibiotic treatment and increased protein burden. Finally, a stochastic extension of the model explains non-trivial correlations observed in single cell experiments including the adder principle. This work provides a simple and robust theoretical framework for studying the fundamental principles of cell size determination in unicellular organisms.
Evolving Notch polyQ tracts reveal possible solenoid interference elements
Authors: Erives Albert J.
Published: October 2016

Polyglutamine (polyQ) tracts in regulatory proteins are extremely polymorphic. As functional elements under selection for length, triplet repeats are prone to DNA replication slippage and indel mutations. Many polyQ tracts are also embedded within intrinsically disordered domains, which are less constrained, fast evolving, and difficult to characterize. To identify structural principles underlying polyQ tracts in disordered regulatory domains, here I analyze deep evolution of metazoan Notch polyQ tracts, which can generate alleles causing developmental and neurogenic defects. I show that Notch features polyQ tract turnover that is restricted to a discrete number of conserved “polyQ insertion slots”. Notch polyQ insertion slots are: (i) identifiable by an amphipathic “slot leader” motif; (ii) conserved as an intact C-terminal array in a 1-to-1 relationship with the N-terminal solenoid-forming ankyrin repeats (ARs); and (iii) enriched in carboxamide residues (Q/N), whose sidechains feature dual hydrogen bond donor and acceptor atoms. Correspondingly, the terminal loop and β-strand of each AR feature conserved carboxamide residues, which would be susceptible to folding interference by hydrogen bonding with residues outside the ARs. I thus suggest that Notch polyQ insertion slots constitute an array of AR interference elements (ARIEs). Notch ARIEs would dynamically compete with the delicate serial folding induced by adjacent ARs. Huntingtin, which harbors solenoid-forming HEAT repeats, also possesses a similar number of polyQ insertion slots. These results strongly suggest that intrinsically disordered interference arrays featuring carboxamide and polyQ enrichment are coupled proteodynamic modulators of solenoids.

SIGNIFICANCE

Neurodegenerative disorders are often caused by expanded polyglutamine (polyQ) tracts embedded in the disordered regions of regulatory proteins, which are difficult to characterize structurally. To identify functional principles underlying polyQ tracts in disordered regulatory domains, I analyze evolution of the Notch protein, which can generate polyQ-related alleles causing neurodevelopmental defects. I show that Notch evolves polyQ tracts that come and go in a few conserved “polyQ insertion slots”. Several features suggest these slots are ankyrin repeat (AR) interference elements, which dynamically compete with the delicate solenoid formed by Notch. Huntingtin, whose polyQ expansions causes Huntington’s Disease in humans, also has solenoid-forming modules and polyQ insertion slots, suggesting a common architectural principle underlies solenoid-forming polyQ-rich proteins.
Halogen-bonded network of trinuclear copper(II) 4-iodopyrazolate complexes formed by mutual breakdown of chloroform and nanojars
Authors: Surmann Stuart A. , Mezei Gellert
Published: October 2016

Crystals of bis(tetrabutylammonium) di-μ3-chlorido-tris(μ2-4-iodopyrazolato-κ2
N:N′)tris[chloridocuprate(II)] 1,4-dioxane hemisolvate, (C16H36N)2[Cu3(C3H2IN2)3Cl5]·0.5C4H8O or (Bu4N)2[CuII
3(μ
3-Cl)2(μ-4-I-pz)3Cl3]·0.5C4H8O, were obtained by evaporating a solution of (Bu4N)2[{CuII(μ-OH)(μ-4-I-pz)}
n
CO3] (n = 27–31) nanojars in chloroform/1,4-dioxane. The decomposition of chloroform in the presence of oxygen and moisture provides HCl, which leads to the breakdown of nanojars to the title trinuclear copper(II) pyrazolate complex, and possibly CuII ions and free 4-iodopyrazole. CuII ions, in turn, act as catalyst for the accelerated decomposition of chloroform, ultimately leading to the complete breakdown of nanojars. The crystal structure presented here provides the first structural description of a trinuclear copper(II) pyrazolate complex with iodine-substituted pyrazoles. In contrast to related trinuclear complexes based on differently substituted 4-R-pyrazoles (R = H, Cl, Br, Me), the [Cu3(μ-4-I-pz)3Cl3] core in the title complex is nearly planar. This difference is likely a result of the presence of the iodine substituent, which provides a unique, novel feature in copper pyrazolate chemistry. Thus, the iodine atoms form halogen bonds with the terminal chlorido ligands of the surrounding complexes [mean length of I...Cl contacts = 3.48 (1) Å], leading to an extended two-dimensional, halogen-bonded network along (-110). The cavities within this framework are filled by centrosymmetric 1,4-dioxane solvent molecules, which create further bridges via C—H...Cl hydrogen bonds with terminal chlorido ligands of the trinuclear complex not involved in halogen bonding.
4-Benzyloxy-1-oxaspiro[4.6]undec-3-en-2-one
Authors: Quintana Mendoza Jose H. , Henao J. A. , Robles Marin Elvis , Urbina Gonzalez Juan Manuel
Published: October 2016

The title compound, C17H20O3, the cycloheptane ring adopts a slightly distorted chair conformation. The planar five-membered ring is inclined at 57.13 (11)° to the phenyl ring of the benzyloxy substituent. In the crystal structure, C—H...O and C—H...π hydrogen bonds generate layers in the ac plane.
Chemotherapy reaction induced by ixabepilone, a microtubule stabilizing agent, mimicking extramammary Paget's disease in a patient with breast carcinoma
Authors: Millsop Jillian W. , Sharon Victoria R. , Petukhova Tatyana , Fung Maxwell A. , Kiuru Maija
Published: October 2016

The histopathologic characteristics of reactions caused by the many novel anticancer agents are under‐recognized. We report a case of a 67‐year‐old female with locally advanced metastatic breast cancer, who initially presented with an extensive reticulated erythematous patch on the trunk caused by intravascular metastases confirmed by a skin biopsy. Owing to disease progression, she was started on ixabepilone, a mitotic inhibitor. While receiving ixabepilone, another skin biopsy was obtained and initially interpreted as extramammary Paget's disease. However, the biopsy showed metaphase arrest of numerous keratinocytes in the basilar and suprabasilar epidermis. Atypical epithelial cells were only present in the intravascular spaces similar to the initial biopsy. Given the temporal association between the initiation of ixabepilone therapy and the epidermal mitotic arrest, a diagnosis of chemotherapy reaction to ixabepilone was rendered. Ixabepilone is an analog of epothilone, a microtubule stabilizer causing mitotic arrest of the cell cycle approved for the treatment of metastatic and locally advanced treatment‐resistant breast cancer. The demonstration of epidermal mitotic arrest caused by ixabepilone is without precedent. The case emphasizes the importance of considering a chemotherapy reaction in the histologic differential diagnosis of epidermal mitotic arrest in a cancer patient receiving chemotherapy.