bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of the robustness of terminal turnaround arrangements for railways
Authors: Hasegawa Daisuke , Nicholson Gemma , Roberts Clive , Schmid Felix
Published: January 2016

The application of Lean principles to terminus operations of high‐speed railways has the potential of enhancing the efficiency of resource usage during both the construction and operation periods, through faster turnarounds and, hence, a reduced space requirement thanks to fewer platform tracks being needed. However, this greater efficiency must not be allowed to result in less robust services. The robust design of products and processes has been studied extensively in the manufacturing industry. By contrast, the robustness of high level railway operational concepts and system design has been investigated rarely. In this study, Taguchi methods that originated in the manufacturing industry are applied to a robustness assessment of system designs in the context of railway operations. The approach is used to assess terminus designs with different numbers of platform tracks, layouts with particular conflict patterns, minimum required turnaround times and signalling facility capability. The authors use a Monte–Carlo simulation with statistical delay distributions. The simulation results show that the signalling system's capability is the most important factor in achieving high capacity and that the robustness of railway terminus operations is not affected by adopting faster turnaround and having fewer platform tracks at termini. Finally, some suggestions for future planning are presented.
Innovative manufacturing approach for paper‐based substrate integrated waveguide components and antennas
Authors: Moscato Stefano , Moro Riccardo , Pasian Marco , Bozzi Maurizio , Perregrini Luca
Published: January 2016

This study presents a novel low‐cost manufacturing technique for paper‐based microwave components. In particular, this work is focused on the implementation of substrate integrated waveguide (SIW) passive circuits and antennas. The proposed manufacturing technique requires the preliminary preparation of the metallised paper substrate, obtained by stacking different layers of paper, and eventually gluing two aluminium foils on both faces of the paper substrate. Subsequently, the circuit pattern is obtained by milling machining. Finally, as the SIW structures require metal vias, cylindrical holes are obtained by drilling and then metallised by conductive paste, by adopting a particular technique. The different steps are detailed in this study, and the basic features of the proposed technique are compared with the traditional ink‐jet‐printing technology typically used for paper‐based microwave circuits. Moreover, the fabrication and testing of several SIW components and antennas are presented in a comprehensive way, to demonstrate the potential of the proposed manufacturing technique and its applicability to the development of the next generation of eco‐friendly wireless systems.
Observer‐based scheme for tuning the control of variable speed wind turbines operating in hostile environments
Authors: Caruana Cedric , Al‐Durra Ahmed , Blaabjerg Frede
Published: January 2016

The rapid growth rate of wind energy coupled with the increasing sizes of individual wind turbines strengthens the need for optimised wind energy capture. This study utilises the unknown input observer to track the variation of the maximal value of wind turbines’ power coefficient to tune the control law. The proposed observer identifies variations in the power coefficient surface over time due to the effect of the environment on the rotor blades. Simulations for both open‐ and closed‐loop operations are shown. The proposed technique shows the potential to alleviate the performance degradation during the lifetime of wind turbines operating in hostile environments.
DSTATCOM supported induction generator for improving power quality
Authors: Sekhar Valluri Chandra , Kant Krishan , Singh Bhim
Published: January 2016

This paper presents an implementation of sliding mode controller (SMC) along with a proportional and integral (PI) controller for a DSTATCOM (Distribution STATic COMpensator) for improving current induced power quality issues and voltage regulation of three‐phase self‐excited induction generator (SEIG). The use of SMC for regulating the DC link voltage of DSTATCOM offers various advantages such as reduction in number of sensors for estimating reference currents and the stable DC link voltage during transient conditions. The use of PI controller for terminal voltage control gives the error free voltage regulation in steady state conditions. The voltage regulation feature of DSTATCOM offers the advantages of single point voltage operation at the generator terminals with the reactive power compensation which avoids the saturation in the generator. Other offered advantages are balanced generator currents under any loading condition, harmonic currents mitigation, stable DC link voltage and the reduced number of sensors. The SMC algorithm is successfully implemented on a DSTATCOM employed with a three‐phase SEIG feeding single phase or three phase loads. The performance of the proposed control algorithm is found satisfactory for voltage regulation and mitigation of power quality problems like reactive power compensation, harmonics elimination, and load balancing under nonlinear/linear loads.
Iliac Crest Bone Graft versus Local Autograft or Allograft for Lumbar Spinal Fusion: A Systematic Review
Authors: Tuchman Alexander , Brodke Darrel S. , Youssef Jim A. , Meisel Hans-Jörg , Dettori Joseph R. , Park Jong-Beom , Yoon S. Tim , Wang Jeffrey C.
Published: January 2016

Study Design

Systematic review.

Objective

To compare the effectiveness and safety between iliac crest bone graft (ICBG) and local autologous bone and allograft in the lumbar spine.

Methods

A systematic search of multiple major medical reference databases identified studies evaluating spinal fusion in patients with degenerative joint disease using ICBG, local autograft, or allograft in the thoracolumbar spine.

Results

Six comparative studies met our inclusion criteria. A “low” strength of the overall body of evidence suggested no difference in fusion percentages in the lumbar spine between local autograft and ICBG. We found no difference in fusion percentages based on low evidence comparing allograft with ICBG autograft. There were no differences in pain or functional results comparing local autograft or allograft with ICBG autograft. Donor site pain and hematoma/seroma occurred more frequently in ICBG autograft group for lumbar fusion procedures. There was low evidence around the estimate of patients with donor site pain following ICBG harvesting, ranging from 16.7 to 20%. With respect to revision, low evidence demonstrated no difference between allograft and ICBG autograft. There was no evidence comparing patients receiving allograft with local autograft for fusion, pain, functional, and safety outcomes.

Conclusion

In the lumbar spine, ICBG, local autograft, and allograft have similar effectiveness in terms of fusion rates, pain scores, and functional outcomes. However, ICBG is associated with an increased risk for donor site-related complications. Significant limitations exist in the available literature when comparing ICBG, local autograft, and allograft for lumbar fusion, and thus ICBG versus other fusion methods necessitates further investigation.
Analysis of von Kármán’s swirling flow on a rotating disc in Bingham fluids
Authors: Guha Abhijit , Sengupta Sayantan
Published: January 2016

In this article, the flow above a rotating disc, which was first studied by von Kármán for a Newtonian fluid, has been investigated for a Bingham fluid in three complementary but separate ways: by computational fluid dynamics (CFD), by a semi-analytical approach based on a new transformation law, and by another semi-analytical approach based on von Kármán’s transformation. The full equations, which consist of a set of partial differential equations, are solved by CFD simulations. The semi-analytical approach, in which a set of ordinary differential equations is solved, is developed here by simplifying the full equations invoking several assumptions. It is shown that the new transformation law performs better and reduces to von Kármán’s transformation as a limiting case. The present paper provides a closed-form expression for predicting the non-dimensional moment coefficient which works well in comparison with values obtained by the full CFD simulations. Detailed variations of tangential, axial, and radial components of the velocity field as a function of Reynolds number (Re) and Bingham number (Bn) have been determined. Many subtle flow physics and fluid dynamic issues are explored and critically explained for the first time in this paper. It is shown how two opposing forces, viz., the viscous and the inertial forces, determine certain important characteristics of the axial-profiles of non-dimensional radial velocity (e.g., the decrease of maxima, the shift of maxima, and the crossing over). It has been found that, at any Re, the maximum value of the magnitude of non-dimensional axial velocity decreases with an increase in Bn, thereby decreasing the net radial outflow. A comparison between the streamline patterns in Newtonian and Bingham fluids shows that, for a Bingham fluid, a streamline close to the disc-surface makes a higher number of complete turns around the axis of rotation. The differences between the self-similarity in a Newtonian fluid flow and the non-similarity in a Bingham fluid flow are expounded with the help of a few compelling visual representations. Some major differences and similarities between the flow of a Newtonian fluid above a rotating disc and that of a Bingham fluid, deduced in the present investigation, are brought together in a single table for ready reference. Two limiting cases, viz. Bn → 0 and Re → ∞, are considered. The present results show that the Bingham fluid solution progressively approaches the von Kármán’s solution for a Newtonian fluid as the Bingham number is progressively reduced to zero (Bn → 0). It is also established here that, for finite values of Bn, the Bingham fluid solution progressively approaches the von Kármán’s solution for a Newtonian fluid as the non-dimensional radius and Reynolds number increase. The higher the value of Bn, the higher is the required value of Re at which convergence with the solution for Newtonian fluid occurs.
Vorticity transformation in high Karlovitz number premixed flames
Authors: Bobbitt Brock , Lapointe Simon , Blanquart Guillaume
Published: January 2016

To better understand the two-way coupling between turbulence and chemistry, the changes in turbulence characteristics through a premixed flame are investigated. Specifically, this study focuses on vorticity, ω, which is characteristic of the smallest length and time scales of turbulence, analyzing its behavior within and across high Karlovitz number (Ka) premixed flames. This is accomplished through a series of direct numerical simulations (DNS) of premixed n-heptane/air flames, modeled with a 35-species finite-rate chemical mechanism, whose conditions span a wide range of unburnt Karlovitz numbers and flame density ratios. The behavior of the terms in the enstrophy, ω2 = ω ⋅ ω, transport equation is analyzed, and a scaling is proposed for each term. The resulting normalized enstrophy transport equation involves only a small set of parameters. Specifically, the theoretical analysis and DNS results support that, at high Karlovitz number, enstrophy transport obtains a balance of the viscous dissipation and production/vortex stretching terms. It is shown that, as a result, vorticity scales in the same manner as in homogeneous, isotropic turbulence within and across the flame, namely, scaling with the inverse of the Kolmogorov time scale, τη. As τη is a function only of the viscosity and dissipation rate, this work supports the validity of Kolmogorov’s first similarity hypothesis in premixed turbulent flames for sufficiently high Ka numbers. Results are unaffected by the transport model, chemical model, turbulent Reynolds number, and finally the physical configuration.
On the wettability transparency of graphene-coated silicon surfaces
Authors: Ramos-Alvarado Bladimir , Kumar Satish , Peterson G. P.
Published: January 2016

In order to better understand the behavior and governing characteristics of the wetting transparency phenomenon observed in graphene-coated surfaces, molecular dynamics simulations were coupled with a theoretical model. Graphene-coated silicon was selected for this analysis, due to potential applications of hybrid silicon-graphene materials as detectors in aqueous environments. The results indicate good agreement between the theory and simulations at the macroscopic conditions required to observe wetting transparency. A microscopic analysis was also conducted in order to identify the parameters, such as the interaction potential energy landscape and the interfacial liquid structure that govern the wetting behavior of graphene-coated surfaces. The interfacial liquid structure was found to be different between uncoated Si(100) and the graphene-coated version and very similar between uncoated Si(111) and the graphene-coated version. However, the concentration of liquid particles for both silicon surfaces was found to be very similar under transparent wetting conditions.
Observations of the high vibrational levels of the B′′B̄ 1Σu+ state of H2
Authors: Chartrand A. M. , Duan W. , Ekey R. C. , McCormack E. F.
Published: January 2016

Double-resonance laser spectroscopy via the EF 1Σg+,v′=6,J′=0–2 state was used to probe the high vibrational levels of the B′′B̄ 1Σu+ state of molecular hydrogen. Resonantly enhanced multiphoton ionization spectra were recorded by detecting ion production as a function of energy using a time of flight mass spectrometer. New measurements of energies for the v = 51–66 levels for the B′′B̄ state of H2 are reported, which, taken with previous results, span the v = 46–69 vibrational levels. Results for energy levels are compared to theoretical close-coupled calculations [L. Wolniewicz, T. Orlikowski, and G. Staszewska, J. Mol. Spectrosc. 238, 118–126 (2006)]. The average difference between the 84 measured energies and calculated energies is −3.8 cm−1 with a standard deviation of 5.3 cm−1. This level of agreement showcases the success of the theoretical calculations in accounting for the strong rovibronic mixing of the 1Σu+ and 1Πu+ states. Due to the ion-pair character of the outer well, the observed energies of the vibrational levels below the third dissociation limit smoothly connect with previously observed energies of ion-pair states above this limit. The results provide an opportunity for testing a heavy Rydberg multi-channel quantum defect analysis of the high vibrational states below the third dissociation limit.
Insight into interfacial effect on effective physical properties of fibrous materials. I. The volume fraction of soft interfaces around anisotropic fibers
Authors: Xu Wenxiang , Wang Han , Niu Yanze , Bai Jingtao
Published: January 2016

With advances in interfacial properties characterization technologies, the interfacial volume fraction is a feasible parameter for evaluating effective physical properties of materials. However, there is a need to determine the interfacial volume fraction around anisotropic fibers and a need to assess the influence of such the interfacial property on effective properties of fibrous materials. Either ways, the accurate prediction of interfacial volume fraction is required. Towards this end, we put forward both theoretical and numerical schemes to determine the interfacial volume fraction in fibrous materials, which are considered as a three-phase composite structure consisting of matrix, anisotropic hard spherocylinder fibers, and soft interfacial layers with a constant dimension coated on the surface of each fiber. The interfacial volume fraction actually represents the fraction of space not occupied by all hard fibers and matrix. The theoretical scheme that adopts statistical geometry and stereological theories is essentially an analytic continuation from spherical inclusions. By simulating such three-phase chopped fibrous materials, we numerically derive the interfacial volume fraction. The theoretical and numerical schemes provide a quantitative insight that the interfacial volume fraction depends strongly on the fiber geometries like fiber shape, geometric size factor, and fiber size distribution. As a critical interfacial property, the present contribution can be further drawn into assessing effective physical properties of fibrous materials, which will be demonstrated in another paper (Part II) of this series.
Boron nitride as two dimensional dielectric: Reliability and dielectric breakdown
Authors: Ji Yanfeng , Pan Chengbin , Zhang Meiyun , Long Shibing , Lian Xiaojuan , Miao Feng , Hui Fei , Shi Yuanyuan , Larcher Luca , Wu Ernest , Lanza Mario
Published: January 2016

Boron Nitride (BN) is a two dimensional insulator with excellent chemical, thermal, mechanical, and optical properties, which make it especially attractive for logic device applications. Nevertheless, its insulating properties and reliability as a dielectric material have never been analyzed in-depth. Here, we present the first thorough characterization of BN as dielectric film using nanoscale and device level experiments complementing with theoretical study. Our results reveal that BN is extremely stable against voltage stress, and it does not show the reliability problems related to conventional dielectrics like HfO2, such as charge trapping and detrapping, stress induced leakage current, and untimely dielectric breakdown. Moreover, we observe a unique layer-by-layer dielectric breakdown, both at the nanoscale and device level. These findings may be of interest for many materials scientists and could open a new pathway towards two dimensional logic device applications.
Development of a precision reverse offset printing system
Authors: Kim Hyunchang , Lee Eonseok , Choi Young-Man , Kwon Sin , Lee Seunghyun , Jo Jeongdai , Lee Taik-Min , Kang Dongwoo
Published: January 2016

In printed electronics technology, the overlay accuracy of printed patterns is a very important issue when applying printing technology to the production of electric devices. In order to achieve accurate positioning of the printed patterns, this study proposes a novel precision reverse offset printing system. Furthermore, the study evaluates the effects of synchronization and printing force on position errors of the printed patterns, and presents methods of controlling synchronization and printing force so as to eliminate positional errors caused by the above-mentioned reasons. Finally, the printing position repeatability of 0.40 μm and 0.32 μm (x and y direction, respectively) at a sigma level is obtained over the dimension of 100 mm under repeated printing tests with identical printing conditions.
Pyridine on flat Pt(111) and stepped Pt(355)—An in situ HRXPS investigation of adsorption and thermal evolution
Authors: Wöckel Claudia , Eilert Andrè , Welke Martin , Schöppke Matthias , Steinrück Hans-Peter , Denecke Reinhard
Published: January 2016

We investigated the adsorption and reaction of pyridine on flat Pt(111) and stepped Pt(355) surfaces via high-resolution in situ x-ray photoelectron spectroscopy. The surfaces were exposed to pyridine at temperatures between 112 and 300 K while simultaneously recording XP spectra. Subsequently, the crystals were annealed and the temperature dependencies of the N 1s and C 1s core levels were studied again in a continuous and quantitative way. Various surface species were found, namely, physisorbed, flat-lying and end-on pyridine, α-pyridyl species on the terraces and on the steps and several unidentified high temperature species. We were able to show an influence of the steps of Pt(355) by pre-adsorbing silver next to the step, which selectively suppresses the step adsorption.
Facile fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) nanodot arrays for organic ferroelectric memory
Authors: Fang Huajing , Yan Qingfeng , Geng Chong , Chan Ngai Yui , Au Kit , Yao Jianjun , Ng Sheung Mei , Leung Chi Wah , Li Qiang , Guo Dong , Wa Chan Helen Lai , Dai Jiyan
Published: January 2016

Nano-patterned ferroelectric materials have attracted significant attention as the presence of two or more thermodynamically equivalent switchable polarization states can be employed in many applications such as non-volatile memory. In this work, a simple and effective approach for fabrication of highly ordered poly(vinylidene fluoride–trifluoroethylene) P(VDF-TrFE) nanodot arrays is demonstrated. By using a soft polydimethylsiloxane mold, we successfully transferred the 2D array pattern from the initial monolayer of colloidal polystyrene nanospheres to the imprinted P(VDF-TrFE) films via nanoimprinting. The existence of a preferred orientation of the copolymer chain after nanoimprinting was confirmed by Fourier transform infrared spectra. Local polarization switching behavior was measured by piezoresponse force microscopy, and each nanodot showed well-formed hysteresis curve and butterfly loop with a coercive field of ∼62.5 MV/m. To illustrate the potential application of these ordered P(VDF-TrFE) nanodot arrays, the writing and reading process as non-volatile memory was demonstrated at a relatively low voltage. As such, our results offer a facile and promising route to produce arrays of ferroelectric polymer nanodots with improved piezoelectric functionality.
Origin of ultrahigh piezoelectric activity of [001]-oriented ferroelectric single crystals at the morphotropic phase boundary
Authors: Ke X. Q. , Wang D. , Wang Y.
Published: January 2016

The physical origin of the ultrahigh piezoelectricity of [001]-oriented ferroelectric single crystals at the morphotropic phase boundary (MPB) is investigated via computer simulations using the phase field method. A wide composition range is explored and the existence of a monoclinic phase at the MPB is considered. The relative contributions from polarization rotation and domain wall motion are discriminated. The domain structures, hysteresis and hysteresis-free strain-electric field curves, and change of d33 as a function of composition for poled samples near the MPB predicted by the simulations are all in agreement with experimental observations. It is found that under small polarization anisotropy the ultrahigh piezoelectricity of [001]-oriented ferroelectric single crystals at the MPB originates mainly from polarization rotation. Although domain wall motion also takes place for poled samples with monoclinic nanodomain structures and contributes to the hysteresis, its contribution to the ultrahigh piezoelectricity is insignificant.
Structural basis for m7G recognition and 2′-O-methyl discrimination in capped RNAs by the innate immune receptor RIG-I
Authors: Devarkar Swapnil C. , Wang Chen , Miller Matthew T. , Ramanathan Anand , Jiang Fuguo , Khan Abdul G. , Patel Smita S. , Marcotrigiano Joseph
Published: January 2016

Significance

The cytosolic innate immune receptor Retinoic Acid Inducible Gene-I (RIG-I) is the principal detector of pathogenic RNAs carrying a 5′-triphosphate (5′ppp). Self RNAs like mRNAs evade recognition by RIG-I due to posttranscriptional modifications like 5′-end capping with 7-methyl guanosine (m7G) and 2′-O-methylation of 5′-end nucleotides. Viruses have also evolved mechanisms to mimic these modifications, which in part is believed to aid in immune evasion. Currently, it is unclear how these modifications modulate RIG-I recognition. This paper provides structural and mechanistic insights into the roles of the m7G cap and 2′-O-methylation in RIG-I evasion. We show that RIG-I accommodates the m7G base while maintaining the 5′ppp contacts and can recognize Cap-0 RNAs but not Cap-1.
How faceted liquid droplets grow tails
Authors: Guttman Shani , Sapir Zvi , Schultz Moty , Butenko Alexander V. , Ocko Benjamin M. , Deutsch Moshe , Sloutskin Eli
Published: January 2016

Significance

Rounded oil-in-water emulsion droplets are ubiquitous in life and technology. We demonstrate that crystallization of the monomolecular nanolayer at the interface of these droplets provides a novel way to control the shape of liquid droplets. In particular, the droplets undergo a spontaneous faceting transition, split, and grow tails. All these transitions are fully temperature-controllable and reversible. The observed phenomena mimic shape selection in virus capsids, virus-associated pyramid formation in lipid membranes, and the growth of rod-like bacteria, yet the underlying mechanism is completely new. The observed effects allow formation of emulsions with controllable attributes, probe the fundamentals of molecular-scale elasticity, and open new routes for self-assembly of complex-shape colloids.
Growth factors and medium hyperglycemia induce Sox9+ductal cell differentiation into β cells in mice with reversal of diabetes
Authors: Zhang Mingfeng , Lin Qing , Qi Tong , Wang Tiankun , Chen Ching-Cheng , Riggs Arthur D. , Zeng Defu
Published: January 2016

Significance

Whether or not SRY (sex-determining region Y)-box 9+(Sox9+) pancreatic ductal cells can give rise to insulin-producing β cells in adult mice remains controversial. Using lineage-tracing techniques, we demonstrate that pancreatic Sox9+ductal cells can be induced to differentiate into β cells under conditions of medium hyperglycemia. Long-term administration of low-dose, but not short-term administration of high-dose, gastrin and epidermal growth factors can augment this differentiation, resulting in formation of new β cells with reversal of diabetes. This study provides previously unidentified insight into β-cell regeneration from ductal cells in diabetic adult individuals.
The tyrosine-sorting motif of the vacuolar sorting receptor VSR4 from Arabidopsis thaliana, which is involved in the interaction between VSR4 and AP1M2, μ1-adaptin type 2 of clathrin adaptor complex 1 subunits, participates in the post-Golgi sorting of VSR4
Authors: Nishimura Kohji , Matsunami Erika , Yoshida Shohei , Kohata Shuhei , Yamauchi Junji , Jisaka Mitsuo , Nagaya Tsutomu , Yokota Kazushige , Nakagawa Tsuyoshi
Published: January 2016

μ1-Adaptin of adaptor protein (AP) 1 complex, AP1M, is generally accepted to load cargo proteins into clathrin-coated vesicles (CCVs) at the trans-Golgi network through its binding to cargo-recognition sequences (CRSs). Plant vacuolar-sorting receptors (VSRs) function in sorting vacuolar proteins, which are reportedly mediated by CCV. We herein investigated the involvement of CRSs of Arabidopsis thaliana VSR4 in the sorting of VSR4. The results obtained showed the increased localization of VSR4 at the plasma membrane or vacuoles by mutations in CRSs including the tyrosine-sorting motif YMPL or acidic dileucine-like motif EIRAIM, respectively. Interaction analysis using the bimolecular fluorescence complementation (BiFC) system, V10-BiFC, which we developed, indicated an interaction between VSR4 and AP1M2, AP1M type 2, which was attenuated by a YMPL mutation, but not influenced by an EIRAIM mutation. These results demonstrated the significance of the recognition of YMPL in VSR4 by AP1M2 for the post-Golgi sorting of VSR4.
Visual and acoustic information supporting a happily expressed speech-in-noise advantage
Authors: Gordon Michael S. , Ancheta Johanna
Published: January 2016

There was an advantage found for recognizing happily expressed audio and audio-visual speech-in-noise relative to speech spoken with neutral or sad expressions. The advantage of happily expressed speech was explored in a set of visual and acoustic manipulations designed to isolate the potential contributions from each signal. For this research, a replication of previous research with the happily expressed speech advantage was completed with a novel inclusion of a learning paradigm. Additional experiments directly investigated the role of the fundamental frequency of the voice for affect, and the affective facial components with the eyes and mouth. We found that the happily expressed speech advantage persisted despite constraints to the amount of frequency modulation and with distortions to the talker's face. These findings seem largely attributable to the influences of affect on low-level acoustical and articulatory information, with only a very subtle role of approach/withdrawal motivation.
Pulmonary Artery Denervation for Treatment of a Patient with Pulmonary Hypertension Secondary to Left Heart Disease
Authors: Zhang Hang , Zhang Juan , Xie Du‐Jiang , Jiang Xiaoming , Zhang Feng‐Fu , Chen Shao‐Liang
Published: January 2016

Pulmonary hypertension (PH) predicts poor outcome in patients with left heart disease. A 62‐year‐old man was referred for heart failure associated with ischemic cardiomyopathy. He received a diagnosis of combined postcapillary and precapillary PH secondary to left heart disease on the basis of hemodynamic parameters. After the pulmonary artery denervation procedure was performed, hemodynamic parameters were markedly improved, which resulted in a significant increase in functional capacity.
Radial positive definite functions and Schoenberg matrices with negative eigenvalues
Authors: Golinskii L. , Malamud M. , Oridoroga L.
Published: January 2016

The main object under consideration is a class

Φ
n

∖

Φ

n
+
1

\Phi _n\backslash \Phi _{n+1}

of radial positive definite functions on

R

n

\mathbb {R}^n

which do not admit radial positive definite continuation on

R

n
+
1

\mathbb {R}^{n+1}

. We find certain necessary and sufficient conditions on the Schoenberg representation measure

ν
n

\nu _n

of

f
∈

Φ
n

f\in \Phi _n

for

f
∈

Φ

n
+
k

f\in \Phi _{n+k}

,

k
∈

N

k\in \mathbb {N}

. We show that the class

Φ
n

∖

Φ

n
+
k

\Phi _n\backslash \Phi _{n+k}

is rich enough by giving a number of examples. In particular, we give a direct proof of

Ω
n

∈

Φ
n

∖

Φ

n
+
1

\Omega _n\in \Phi _n\backslash \Phi _{n+1}

, which avoids Schoenberg’s theorem;

Ω
n

\Omega _n

is the Schoenberg kernel. We show that
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Omega Subscript n Baseline left-parenthesis a dot right-parenthesis normal upper Omega Subscript n Baseline left-parenthesis b dot right-parenthesis element-of normal upper Phi Subscript n minus normal upper Phi Subscript n plus 1">

Ω
n

(
a
⋅
)

Ω
n

(
b
⋅
)
∈

Φ
n

∖

Φ

n
+
1

\Omega _n(a\cdot )\Omega _n(b\cdot )\in \Phi _n\backslash \Phi _{n+1}

for

a
≠
b

a\not =b

. Moreover, for the square of this function we prove the surprisingly much stronger result

Ω
n
2

(
a
⋅
)
∈

Φ

2
n
−
1

∖

Φ

2
n

\Omega _n^2(a\cdot )\in \Phi _{2n-1}\backslash \Phi _{2n}

. We also show that any

f
∈

Φ
n

∖

Φ

n
+
1

f\in \Phi _n\backslash \Phi _{n+1}

,

n
≥
2

n\ge 2

, has infinitely many negative squares. The latter means that for an arbitrary positive integer

N
N

there is a finite Schoenberg matrix
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper S Subscript upper X Baseline left-parenthesis f right-parenthesis colon equals double-vertical-bar f left-parenthesis StartAbsoluteValue x Subscript i Baseline minus x Subscript j Baseline EndAbsoluteValue Subscript n plus 1 Baseline right-parenthesis double-vertical-bar Subscript i comma j equals 1 Superscript m">

S

X

(
f
)
:=
‖
f
(

|

x
i

−

x
j

|

n
+
1

)

‖

i
,
j
=
1

m

\mathcal {S}_X(f) := \|f(|x_i-x_j|_{n+1})\|_{i,j=1}^{m}

,

X
:=
{

x
j

}

j
=
1

m

⊂

R

n
+
1

X := \{x_j\}_{j=1}^m \subset \mathbb {R}^{n+1}

, which has at least

N
N

negative eigenvalues.
Use of Pigmented Maize in Both Conventional Dry‐Grind and Modified Processes Using Granular Starch Hydrolyzing Enzyme
Authors: Wang Zhaoqin , Huang Haibo , Gonzalez de Mejia Elvira , Li Qian , Singh Vijay
Published: January 2016

In the dry‐grind ethanol process, distillers dried grains with solubles (DDGS) is the main coproduct, which is primarily used as an ingredient in ruminant animal diets. Increasing the value of DDGS will improve the profitability of the dry‐grind ethanol process. One way to increase DDGS value is to use pigmented maize as the feedstock for ethanol production. Pigmented maize is rich in anthocyanin content, and the anthocyanin imparts red, blue, and purple color to the grain. It is reported that anthocyanin would be absorbed by yeast cell walls during the fermentation process. The effects of anthocyanin on fermentation characteristics in the dry‐grind process are not known. In this study, the effects of anthocyanin in conventional (conventional starch hydrolyzing enzymes) and modified (granular starch hydrolyzing enzymes [GSHE]) dry‐grind processes were evaluated. The modified process using GSHE replaced high‐temperature liquefaction. The ethanol conversion efficiencies of pigmented maize were comparable to that of yellow dent corn in both conventional (78.4 ± 0.5% for blue maize, 74.3 ± 0.4% for red maize, 81.2 ± 1.0% for purple maize, and 75.1 ± 0.2% for yellow dent corn) and modified dry‐grind processes using GSHE (83.8 ± 0.8% for blue maize, 81.1 ± 0.3% for red maize, 93.5 ± 0.8% for purple maize, and 85.6 ± 0.1% for yellow dent corn). Total anthocyanin content in DDGS from the modified process was 1.4, 1.9, and 2.4 times of that from the conventional process for purple, red, and blue maize samples, respectively. These results indicated that pigmented maize rich in anthocyanin did not negatively affect the fermentation characteristics of the dry‐grind process and that there was a potential to use pigmented maize in the dry‐grind process, especially when using GSHE.
The Pediatrics Milestones Assessment Pilot: Development of Workplace-Based Assessment Content, Instruments, and Processes
Authors: Hicks Patricia J. , Margolis Melissa , Poynter Sue E. , Chaffinch Christa , Tenney-Soeiro Rebecca , Turner Teri L. , Waggoner-Fountain Linda , Lockridge Robin , Clyman Stephen G. , Schwartz Alan
Published: January 2016

Purpose

To report on the development of content and user feedback regarding the assessment process and utility of the workplace-based assessment instruments of the Pediatrics Milestones Assessment Pilot (PMAP).

Method

One multisource feedback instrument and two structured clinical observation instruments were developed and refined by experts in pediatrics and assessment to provide evidence for nine competencies based on the Pediatrics Milestones (PMs) and chosen to inform residency program faculty decisions about learners’ readiness to serve as pediatric interns in the inpatient setting. During the 2012–2013 PMAP study, 18 U.S. pediatric residency programs enrolled interns and subinterns. Faculty, residents, nurses, and other observers used the instruments to assess learner performance through direct observation during a one-month rotation. At the end of the rotation, data were aggregated for each learner, milestone levels were assigned using a milestone classification form, and feedback was provided to learners. Learners and site leads were surveyed and/or interviewed about their experience as participants.

Results

Across the sites, 2,338 instruments assessing 239 learners were completed by 630 unique observers. Regarding end-of-rotation feedback, 93% of learners (128/137) agreed the assessments and feedback “helped me understand how those with whom I work perceive my performance,” and 85% (117/137) agreed they were “useful for constructing future goals or identifying a developmental path.” Site leads identified several benefits and challenges to the assessment process.

Conclusions

PM-based instruments used in workplace-based assessment provide a meaningful and acceptable approach to collecting evidence of learner competency development. Learners valued feedback provided by PM-based assessment.
IMAGING WITH MULTIMODAL ADAPTIVE-OPTICS OPTICAL COHERENCE TOMOGRAPHY IN MULTIPLE EVANESCENT WHITE DOT SYNDROME: THE STRUCTURE AND FUNCTIONAL RELATIONSHIP
Authors: Labriola Leanne T. , Legarreta Andrew D. , Legarreta John E. , Nadler Zach , Gallagher Denise , Hammer Daniel X. , Ferguson R. Daniel , Iftimia Nicusor , Wollstein Gadi , Schuman Joel S.
Published: January 2016

Purpose:

To elucidate the location of pathological changes in multiple evanescent white dot syndrome (MEWDS) with the use of multimodal adaptive optics (AO) imaging.

Methods:

A 5-year observational case study of a 24-year-old female with recurrent MEWDS. Full examination included history, Snellen chart visual acuity, pupil assessment, intraocular pressures, slit lamp evaluation, dilated fundoscopic exam, imaging with Fourier-domain optical coherence tomography (FD-OCT), blue-light fundus autofluorescence (FAF), fundus photography, fluorescein angiography, and adaptive-optics optical coherence tomography.

Results:

Three distinct acute episodes of MEWDS occurred during the period of follow-up. Fourier-domain optical coherence tomography and adaptive-optics imaging showed disturbance in the photoreceptor outer segments (PR OS) in the posterior pole with each flare. The degree of disturbance at the photoreceptor level corresponded to size and extent of the visual field changes. All findings were transient with delineation of the photoreceptor recovery from the outer edges of the lesion inward. Hyperautofluorescence was seen during acute flares. Increase in choroidal thickness did occur with each active flare but resolved.

Conclusion:

Although changes in the choroid and RPE can be observed in MEWDS, Fourier-domain optical coherence tomography, and multimodal adaptive optics imaging localized the visually significant changes seen in this disease at the level of the photoreceptors. These transient retinal changes specifically occur at the level of the inner segment ellipsoid and OS/RPE line. En face optical coherence tomography imaging provides a detailed, yet noninvasive method for following the convalescence of MEWDS and provides insight into the structural and functional relationship of this transient inflammatory retinal disease.
Ventricular Recovery and Pump Explantation in Patients Supported by Left Ventricular Assist Devices: A Systematic Review
Authors: Phan Kevin , Huo Ya Ruth , Zhao Dong Fang , Yan Tristan D. , Tchantchaleishvili Vakhtang
Published: January 2016

Several studies have reported that a portion of patients who exhibit cardiac recovery during left ventricular assist device (LVAD) support can have their device explanted with reasonable long-term survival. The aim of this systematic review is to assess the survival and cardiac function in patients with explanted LVADs from the current literature. Electronic search was performed to identify all studies in English literature assessing LVAD explantation. All identified articles were systematically assessed using the inclusion and exclusion criteria. Selected studies were subjected to quantitative assessment. From 5 electronic databases, 11 studies (213 patients) were included. Pooled mean perioperative mortality rate of those explanted was 9.2% (95% CI, 5.0–14.5%; I2 = 0). Pooled mean late mortality rate was 15% (95% CI, 9.0–22.1%; I2 = 31%). The pooled 1, 5, and 10 year survival postexplant was 91, 76, and 65.7%, respectively. Pooled postweaning freedom from heart failure (HF) recurrence reached 81.3%. Subset analysis demonstrated that patients explanted from a continuous-flow LVAD versus pulsatile LVAD had a lower rate of HF recurrence (6.6 vs. 28.3%, p = 0.03) and LVAD reimplantation (7.5 vs. 37%, p = 0.001). Before LVAD explantation, overall mean left ventricular ejection fraction (LVEF) was 49%. Weighted pooled early and late postexplantation mean LVEF was 47.3 and 41.2%, respectively. Late postexplantation LVEF was significantly higher in the continuous-flow versus pulsatile LVAD subgroup (41.5 vs. 24%, p = 0.001). This review shows encouraging safety and 10 year survival outcomes after explantation of LVADs in carefully selected patients, with rates better than expected after a heart transplant. Recovery of the native heart is the most desirable clinical outcome in patients supported with LVADs and should be actively sought.
Assessing Consequences of Intraaortic Balloon Counterpulsation Versus Left Ventricular Assist Devices at the Time of Heart Transplantation
Authors: Castleberry Anthony W. , DeVore Adam D. , Southerland Kevin W. , Meza James M. , Irish William D. , Rogers Joseph G. , Milano Carmelo A. , Patel Chetan B.
Published: January 2016

The proportion of heart transplant recipients bridged with durable, intracorporeal left ventricular assist devices (dLVADs) has dramatically increased; however, concern exists regarding obligate repeat sternotomy, increased bleeding risk because of anticoagulation and acquired von Willebrand disease, and increased rates of allosensitization. Whether dLVAD patients have impaired posttransplant outcomes compared with equivalent patients with less invasive intraaortic balloon pump counterpulsation (IABP) at the time of transplant is unknown. Therefore, we analyzed adult, first time, heart-only transplant procedures with dLVAD (n = 2,636) compared with IABP (n = 571) at the time of transplant based on data from the United Network for Organ Sharing (UNOS) July 2004 to December 2011. There was clear geographic variation in IABP and dLVAD at transplant. Multivariable analysis demonstrated equivalent cumulative risk of death (adjusted Cox proportional hazard ratio, 1.08; 95% confidence interval, 0.87–1.33; p = 0.51). There was no significant difference in adjusted comparison of perioperative morality, length of stay, postoperative renal failure requiring dialysis, or early acute rejection (p ≥ 0.14 for all). Therefore, data from UNOS suggest that the presence of dLVAD at the time of heart transplantation does not have a detrimental effect on postoperative outcomes compared with IABP, which must be considered in the context of pretransplant mortality and locoregional organ availability.
Outcomes in Patients with Severe Preexisting Renal Dysfunction After Continuous-Flow Left Ventricular Assist Device Implantation
Authors: Raichlin Eugenia , Baibhav Bipul , Lowes Brian D. , Zolty Ronald , Lyden Elizabeth R. , Vongooru Hareeprasad R. , Siddique Aleem , Moulton Michael J. , Um John Y.
Published: January 2016

The aim of this study was to evaluate clinical outcomes after left ventricular assist device (LVAD) implantation in patients with severe pre-LVAD renal dysfunction (RD). The cohort of 165 consecutive patients implanted with HeartMate II LVADs was divided into two groups: 1) baseline glomerular filtration rate (bGFR) ≤ 40 ml/min/1.73 m2 (n = 30), and 2) GFR > 40 ml/min/1.73 m2 (n = 135). In both groups, GFR increased significantly at 1 month and then declined, remaining higher than the pre-LVAD level in the bGFR ≤ 40 group and returning back to the pre-LVAD level in the bGFR > 40 group by 1 year post-LVAD follow-up. Post-LVAD dialysis was used in 20% of the bGFR ≤ 40 patients and 7% of the bGFR > 40 patients (p = 0.02). By 3 months, 14% patients had GFR ≤ 40 ml/min/1.73 m2. Grade ≥2 tricuspid regurgitation (TR) (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.23–10.28; p = 0.02) and model for end-stage liver disease-XI score ≥ 17 (OR, 4.2; 95% CI, 1.45–12.24; p = 0.01) were risk factors for severe RD at 3 months after LVAD implantation. Eight bGFR ≤ 40 patients underwent heart transplantation. Carefully selected patients with advanced heart dysfunction and bGFR ≤ 40 ml/min/1.73 m2 can improve kidney function with LVAD support and be able to bridge to isolated heart transplantation. Additional research is needed to refine patient selection for LVAD.
A Method for Creating Artificial Thrombi In Vitro Using a Rotating Mechanical Surface
Authors: Jessen Staci L. , Masse Andrew M. , Carpenter Mallory D. , Clubb Fred J. , Weeks Brad R.
Published: January 2016

Thromboembolism is a common concern in ventricular assist device (VAD) therapy. Precise VAD response to pass-through thromboembolism needs to be studied in a controlled in vitro setting where specific pump parameters (i.e., power consumption, flow rates, impeller RPM) can be monitored while various types of thrombi are introduced. In this article, we describe a method for creating standardized fibrin thrombi that could be introduced into a mock circulatory loop for testing VAD response to thromboembolism. Donor equine blood collected using a sodium citrate was allowed to clot by adding calcium chloride (CaCl2) while a rotating component applied shear forces to the blood. This rotating force was applied at various speeds and at various distances into the blood. Resulting clots showed similar microscopic features to thrombi taken from explanted clinical VADs. Higher RPM of the rotating component and smaller clearances between the rotating component and the blood created clots that closely resembled ante-explant clots found within VADs in vivo. This method is an effective way to create artificial fibrin clots for use in in vitro experiments to test thromboembolism in VADs.
Early Experience with a Novel Cannulation Strategy for Left Ventricular Decompression during Nonpostcardiotomy Venoarterial ECMO
Authors: Keenan Jeffrey E. , Schechter Matthew A. , Bonadonna Desiree K. , Bartz Raquel R. , Milano Carmelo A. , Schroder Jacob N. , Daneshmand Mani A.
Published: January 2016

Advances in technology for the delivery of venoarterial extracorporeal membrane oxygenation (VA-ECMO) have allowed for its expanded utilization in the treatment of patients with advanced cardiogenic shock, particularly through the use of peripheral cannulation strategies. However, peripheral VA-ECMO continues to be hampered by several major limitations including inadequate decompression of the left ventricle, lower limb ischemia, and the inability to mobilize patients. Here, we present a case series of three patients who were treated with a hybrid peripheral-central cannulation strategy accompanied by direct decompression of the left ventricle through a right anterior mini-thoracotomy. This novel approach ameliorates several of the current limitations to peripheral VA-ECMO therapy and thereby holds potential for improving outcomes in VA-ECMO patients.
Clinicopathologic Characteristics of Hepatocellular Carcinoma With Reactive Ductule-like Components, a Subset of Liver Cancer Currently Classified as Combined Hepatocellular-Cholangiocarcinoma With Stem-Cell Features, Typical Subtype
Authors: Shibahara Junji , Hayashi Akimasa , Misumi Kento , Sakamoto Yoshihiro , Arita Junichi , Hasegawa Kiyoshi , Kokudo Norihiro , Fukayama Masashi
Published: January 2016

The aim of this study was to elucidate the clinicopathologic characteristics of hepatocellular carcinoma with reactive ductule-like components (HCC-RD), corresponding to combined hepatocellular-cholangiocarcinoma (CHC) with stem cell features, typical subtype. Retrospective clinicopathologic analysis was performed on HCCs surgically treated at the University of Tokyo Hospital between 1995 and 2013. RD components were defined as neoplastic ductular structures composed of small “stem/progenitor-like” cells. There were 46 HCC-RDs, comprising about 3% of all HCCs. Thirty-eight cases of CHC, classical type (classical CHC), were identified during the study period. When compared with conventional HCC, HCC-RD was characterized by younger patient age (P=0.016), higher frequency of female patients (P<0.001), and higher serum α-fetoprotein levels (P=0.005). Serum carbohydrate antigen 19-9 elevation was also more frequently observed in HCC-RD than in conventional HCC (P=0.002). Histologically, clear cell constituents and interstitial fibrosis were more frequent in HCC-RD than in conventional HCC (P=0.003 and <0.001, respectively). When compared with HCC-RD and conventional HCC, classical CHC was characterized by a poorly differentiated HCC component, frequent vascular invasion, and lymph node metastasis (P<0.05). There was little prognostic difference between HCC-RD and conventional HCC, whereas overall and disease-free survival in classical CHC was significantly worse than in conventional HCC. In conclusion, although HCC-RDs do have some unique clinicopathologic characteristics, they have no prognostic significance, and it is not reasonable to include these tumors in the CHC category.