bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion-controlled alloying of single-phase multi-principal transition metal carbides with high toughness and low thermal diffusivity
Authors: Peng Chong , Gao Xiang , Wang Mingzhi , Wu Lailei , Tang Hu , Li Xiaomin , Zhang Qian , Ren Yang , Zhang Fuxiang , Wang Yuhui , Zhang Bing , Gao Bo , Zou Qin , Zhao Yucheng , Yang Qian , Tian Dongxia , Xiao Hong , Gou Huiyang , Yang Wenge , Bai Xuedong , Mao Wendy L. , Mao Ho-kwang
Published: January 2019

Multicomponent alloying has displayed extraordinary potential for producing exceptional structural and functional materials. However, the synthesis of single-phase, multi-principal covalent compounds remains a challenge. Here, we present a diffusion-controlled alloying strategy for the realization of covalent multi-principal transition metal carbides (MPTMCs) with a single face-centered cubic phase. The increased interfacial diffusion promoted by the addition of a nonstoichiometric compound leads to rapid formation of the single phase at much lower sintering temperature. Direct atomic-level observations via scanning transmission electron microscopy demonstrate that MPTMCs are composed of a single phase with a random distribution of all cations, which holds the key to the unique combinations of improved fracture toughness, superior Vickers hardness, and extremely lower thermal diffusivity achieved in MPTMCs. The present discovery provides a promising approach toward the design and synthesis of next-generation high-performance materials.
Broadband acoustic converging and asymmetric converging based on thermoacoustic phased arrays
Authors: Sun Hong-xiang , Hou An-ru , Qian Jiao , Ge Yong , Yuan Shou-qi , Guan Yi-Jun , Si Qiao-rui , Liu Xiao-jun
Published: January 2019

We report broadband acoustic converging and asymmetric converging based on mono- and dual-layer thermoacoustic phased arrays of Bessel-like beams, respectively. Based on the thermoacoustic units, we design a converging lens constructed by a monolayer phased array of the Bessel-like beam and demonstrate the large converging region (16.8λ), the broad fractional bandwidth (0.77), and the design feasibility of the converging lens. Besides, by adjusting the phase distribution of the converging lens, the cylindrical acoustic source can also be converged on a large region perfectly. More importantly, we design an asymmetric converging lens by introducing dual-layer phased arrays, in which the acoustic energy can be converged on a large region at a side but cannot pass through the lens at the other side. The converging region can be manipulated by adjusting the distance between two phased arrays. The proposed lenses have the advantages of large converging region, broad bandwidth, weak diffraction, and asymmetric transmission showing excellent potential applications in acoustic devices.
Phase-transition-induced large magnetic anisotropy change in VO2/(Co/Pt)2 heterostructure
Authors: Wei Guodong , Lin Xiaoyang , Si Zhizhong , Lei Na , Chen Yanxue , Eimer Sylvain , Zhao Weisheng
Published: January 2019

Perpendicular magnetic anisotropy (PMA) is one of the most significant technologies to be used in next generation spintronic devices due to its potential for promoting thermal stability and device miniaturization. It is an important issue to find an efficient way to modulate its property in the process of PMA application. In this work, we report the phase-transition controlled magnetic anisotropy modulation in the VO2/(Co/Pt)2 heterostructure, where VO2 is introduced into the system to apply an interfacial strain by its metal-insulator transition. A large reversible modulation of PMA reaching 3 × 105 erg/cm3 is observed during this process. The calculated energy density variation of interfacial anisotropy reaches 0.85 erg/cm2, which shows a significant advantage over traditional modulation strategies. Further experimental results including magnetization change versus temperature, strain buffered modulation, and pre-strained sample comparison prove that the interfacial coupling between VO2 and PMA layers plays a crucial role in this modulation. This work, demonstrating great potential for phase-transition materials in efficient magnetic anisotropy modulation, would benefit the exploration of low-power consumption devices.
Contour forward flux sampling: Sampling rare events along multiple collective variables
Authors: DeFever Ryan S. , Sarupria Sapna
Published: January 2019

Many rare event transitions involve multiple collective variables (CVs), and the most appropriate combination of CVs is generally unknown a priori. We thus introduce a new method, contour forward flux sampling (cFFS), to study rare events with multiple CVs simultaneously. cFFS places nonlinear interfaces on-the-fly from the collective progress of the simulations, without any prior knowledge of the energy landscape or appropriate combination of CVs. We demonstrate cFFS on analytical potential energy surfaces and a conformational change in alanine dipeptide.
Breaking dynamic inversion symmetry in a racemic mixture using simple trains of laser pulses
Authors: Thomas Esben F. , Henriksen Niels E.
Published: January 2019

Recent advances in ultrafast laser technology hint at the possibility of using shaped pulses to generate deracemization via selective enantiomeric conversion; however, experimental implementation remains a challenge and has not yet been achieved. Here, we describe an experiment that can be considered an accessible intermediate step on the road towards achieving laser induced deracemization in a laboratory. Our approach consists of driving a racemic mixture of 3D oriented 3,5-difluoro-3′, 5′-dibromobiphenyl (F2H3C6–C6H3Br2) molecules with a simple train of Gaussian pulses with alternating polarization axes. We use arguments related to the geometry of the field/molecule interaction to illustrate why this will increase the amplitude of the torsional oscillations between the phenyl rings while simultaneously breaking the inversion symmetry of the dynamics between the left- and right-handed enantiomeric forms, two crucial requirements for achieving deracemization. We verify our approach using numerical simulations and show that it leads to significant and experimentally measurable differences in the internal enantiomeric structures when detected by Coulomb explosion imaging.
Magnetic performances and switching behavior of Co-rich CoPtP micro-magnets for applications in magnetic MEMS
Authors: Mallick Dhiman , Paul Kankana , Maity Tuhin , Roy Saibal
Published: January 2019

In this paper, the magnetic properties of Co-rich CoPtP films electrodeposited using an optimized Pulse Reverse (PR) technique are investigated for magnetic MEMS applications. By using a combination of forward and reverse pulses with optimized duty cycles during deposition and suitable bath chemistry, the film stress is reduced significantly, which results in smooth, crack-free films of thickness up to 26 μm. The deposited film of thickness ∼3 μm shows a coercivity of 268 kA/m, a remanence of 0.4 T, and a maximum energy product of 35 kJ/m3 in the out-of-plane direction. The variation in the hard-magnetic properties of the films for changing the film thickness is analyzed in terms of the composition, crystalline structure, and grain size. As the thickness is increased from 0.9 μm to 26 μm, the in-plane coercivity reduces by 17% due to an increase of the grain size and the Co content in the alloy structure. The in-plane squareness factor increases by 1.5 times as the thickness is increased over the above-mentioned range, which results in an enhancement of the in-plane remanence value. The magnetization reversal behavior of the deposited films indicates that the nature of magnetic interaction is significantly influenced by the thickness of the films, where the dipolar interaction for the thinner films changes to exchange coupling at higher thickness due to the increase of the grain size. Finally, an innovative design strategy to integrate CoPtP in magnetic MEMS devices by micro-patterning is proposed and analyzed using the finite element method. The demagnetization fields of the magnetic elements are minimized through optimized micro-patterned structures which improve the viability of PR deposited CoPtP micro-magnets having suitable nano-grains in potential MEMS based applications.
Magnetic field effect on ion pair dynamics upon bimolecular photoinduced electron transfer in solution
Authors: Feskov Serguei V. , Rogozina Marina V. , Ivanov Anatoly I. , Aster Alexander , Koch Marius , Vauthey Eric
Published: January 2019

The dynamics of the ion pairs produced upon fluorescence quenching of the electron donor 9,10-dimethylanthracene (DMeA) by phthalonitrile have been investigated in acetonitrile and tetrahydrofuran using transient absorption spectroscopy. Charge recombination to both the neutral ground state and the triplet excited state of DMeA is observed in both solvents. The relative efficiency of the triplet recombination pathway decreases substantially in the presence of an external magnetic field. These results were analyzed theoretically within the differential encounter theory, with the spin conversion of the geminate ion pairs described as a coherent process driven by the hyperfine interaction. The early temporal evolution of ion pair and triplet state populations with and without magnetic field could be well reproduced in acetonitrile, but not in tetrahydrofuran where fluorescence quenching involves the formation of an exciplex. A description of the spin conversion in terms of rates, i.e., incoherent spin transitions, leads to an overestimation of the magnetic field effect.
Nonlinear dynamics of shear Alfvén fluctuations in divertor tokamak test facility plasmas
Authors: Wang T. , Wang X. , Briguglio S. , Qiu Z. , Vlad G. , Zonca F.
Published: January 2019

Following the analysis on linear spectra of shear Alfvén fluctuations excited by energetic particles (EPs) in the Divertor Tokamak Test (DTT) facility plasmas [Wang et al., Phys. Plasmas 25, 062509 (2018)], in this work, nonlinear dynamics of the corresponding mode saturation and the fluctuation induced EP transport is studied by hybrid magnetohydrodynamic-gyrokinetic simulations. For the reversed shear Alfvén eigenmode driven by magnetically trapped EP precession resonance in the central core region of DTT plasmas, the saturation is mainly due to radial decoupling of resonant trapped EPs. Consistent with the wave-EP resonance structure, EP transport occurs in a similar scale to the mode width. On the other hand, passing EP transport is analyzed in detail for the toroidal Alfvén eigenmode in the outer core region, with mode drive from both passing and trapped EPs. It is shown that passing EPs experience only weak redistributions in the weakly unstable case, and the transport extends to meso-scale diffusion in the strongly unstable case, due to orbit stochasticity induced by resonance overlap. Here, a weakly/strongly unstable regime is determined by the Chirikov condition for resonance overlap. This work then further illuminates rich and diverse nonlinear EP dynamics related to burning plasma studies and the capability of DTT to address these key physics.
Intracavity cold atomic ensemble with high optical depth
Authors: Jiang Yue , Mei Yefeng , Zou Yueyang , Zuo Ying , Du Shengwang
Published: January 2019

We describe the apparatus of an optical cavity loaded with cold 85Rb atoms of high optical depth (OD) in the weak coupling regime. The relevant cavity-atom parameters are the single-photon Rabi frequency g0 = 2π × 0.25 MHz, the cavity power decay rate κ = 2π × 9.0 MHz, and the atomic excited state decay rate Γ = 2π × 5.75 MHz. In this bad-cavity configuration where the atomic natural linewidth (Γ/2π) is less than the cavity linewidth (κ/2π), the cavity enhancement factor for the longitudinal OD is about 188. We obtain a cavity enhanced OD up to 7600, corresponding to an atomic ensemble with a bare single-pass OD of 40, coupled to the cavity mode. Our intracavity cold atomic ensemble with high OD may have many applications in studying collective atom-light interaction inside an optical cavity.
Dielectric and piezoelectric nonlinear properties of slightly textured lead barium niobate ceramics
Authors: Ochoa Diego A. , Casals Jorge A. , Venet Michel , M’Peko Jean-Claude , García Jose E.
Published: January 2019

Dielectric and piezoelectric responses of slightly textured, lead barium niobate ceramics are studied. The designed morphotropic phase boundary composition (Pb0.63Ba0.37Nb2O6) shows considerable nonlinear dielectric and piezoelectric responses. While these nonlinear behaviors lead to significant instabilities of the functional properties, interesting features are revealed as a consequence of the texturing effect in the composition studied. An improved dielectric performance and a lower nonlinear piezoelectric response are observed when the electric field is applied to the sample in the forging direction. The results are quantitatively discussed in the framework of the Preisach and Rayleigh models. In this context, a decrease in the nonlinear response can be associated with a lower grain size related to the texture. The results of this work show that texturing is an effective route for controlling the undesirable nonlinear behavior of piezoceramics with tetragonal tungsten bronze structure.
Gas breakdown and its scaling law in microgaps with multiple concentric cathode protrusions
Authors: Fu Yangyang , Zhang Peng , Krek Janez , Verboncoeur John P.
Published: January 2019

This paper reports gas breakdown characteristics in microgaps with multiple concentric protrusions on the cathode in the transition from the Townsend to the subnormal glow discharge regime, using a two-dimensional hydrodynamic model. The effects of the protrusion aspect ratio, height, and protrusion spacing on the breakdown voltage are investigated. The results show that when the protrusion spacing is small, the shielding effect can play a more important role in the breakdown voltage rather than the protrusion aspect ratio; the breakdown voltage is more sensitive to the protrusion height and can be assessed by the shortest gap distance. Increasing the protrusion spacing decreases the shielding effect, which lowers the breakdown voltage in both low- and high-pressure regimes. It is found that the breakdown scaling law still holds in geometrically similar microgaps with multiple cathode protrusions despite the electric field distortion.
High current variable temperature electrical characterization system for superconducting wires and tapes with continuous sample rotation in a split coil magnet
Authors: Lao M. , Hänisch J. , Kauffmann-Weiss S. , Gehring R. , Fillinger H. , Drechsler A. , Holzapfel B.
Published: January 2019

A new state-of-the-art electrical transport measurement system was developed for the characterization of industrially produced coated conductors (CCs). The current leads are rated to a conduct current of up to 1000 A, which opens up the possibility of measuring the critical current Ic of tapes at a wide range of temperatures. The setup operates in a He-gas flow cryostat that provides stable temperatures between 1.8 and 200 K. The setup is equipped with a split-coil magnet that can apply fields of up to 6 T. A continuous rotation of the sample with respect to the magnetic field with an angular resolution of 0.5° enables characterization of anisotropic Ic of different tapes. In the measured voltage-current curves, weak sample heating mostly occurs from the dissipation in the tape during the Ic transition. It is demonstrated that the system can provide reliable data on the properties of CCs at temperatures lower than 77 K for a magnet design and other applications. The results allow the study of vortex pinning for further prospects of engineering the microstructure of the superconducting layer as well as to assess the performance of various tapes with different architectures to achieve optimum performance at different operating temperatures and magnetic fields.
A modified generalized Langevin oscillator model for activated gas-surface reactions
Authors: Zhou Xueyao , Jiang Bin
Published: January 2019

Surface motion has proven to influence the gas-surface reactions in various ways. An adequate model to describe the complex lattice effects in a relatively simple way is therefore highly desirable. In this work, we have modified the widely used Generalized Langevin Oscillator (GLO) model to incorporate the molecule-surface coupling that plays an important role in activated dissociation of polyatomic molecules on metal surfaces. To this end, taking the well-studied CHD3+Ni(111) system as an example, we add a coupling potential linearly dependent on the surface oscillating coordinate, which becomes essential in predicting the dissociative sticking coefficients for reactive scattering. We further scale the mass of the surface oscillator on the basis of a mechanic coupling parameter, which has significantly improved the description of the molecule-surface energy transfer for nonreactive scattering. This so-called modified GLO (MGLO) model retains the simplicity and advantages of the original GLO, while yields much more accurate dynamics results that are in remarkably good agreement with the benchmark data calculated using ab initio molecular dynamics. We argue that the MGLO model is applicable to these highly activated gas-surface reactions with strong molecule-surface couplings.
Effect of molecular size and hydrogen bonding on three surface-facilitated processes in molecular glasses: Surface diffusion, surface crystal growth, and formation of stable glasses by vapor deposition
Authors: Chen Yinshan , Chen Zhenxuan , Tylinski Michael , Ediger M. D. , Yu Lian
Published: January 2019

Recent work has shown that diffusion and crystal growth can be much faster on the surface of molecular glasses than in the interior and that the enhancement effect varies with molecular size and intermolecular hydrogen bonds (HBs). In a related phenomenon, some molecules form highly stable glasses when vapor-deposited, while others (notably those forming extensive HBs) do not. Here we examine all available data on these phenomena for quantitative structure-property relations. For the systems that form no HBs, the surface diffusion coefficient Ds decreases with increasing molecular size d (d = Ω1/3, where Ω is the molecular volume); when evaluated at the glass transition temperature Tg, Ds decreases ∼5 orders of magnitude for 1 nm of increase in d. Assuming that center-of-mass diffusion is limited by the deepest part of the molecule in the surface-mobility gradient, these data indicate a mobility gradient in reasonable agreement with the Elastically Collective Nonlinear Langevin Equation theory prediction for polystyrene as disjointed Kuhn monomers. For systems of similar d, the Ds value decreases with the extent of intermolecular HB, x (HB), defined as the fraction of vaporization enthalpy due to HB. For both groups together (hydrogen-bonded and otherwise), the Ds data collapse when plotted against d/[1 − x(HB)]; this argues that the HB effect on Ds can be described as a narrowing of the surface mobility layer by a factor [1 − x(HB)] relative to the van der Waals systems. Essentially the same picture holds for the surface crystal growth rate us. The kinetic stability of a vapor-deposited glass decreases with x(HB) but is not better organized by the combined variable d/[1 − x(HB)]. These results indicate that surface crystal growth depends strongly on surface diffusion, whereas the formation of stable glasses by vapor deposition may depend on other factors.
Vitrification of in vitro-derived bovine embryos: targeting enhancement of quality by refining technology and standardising procedures
Authors: Do V. H. , Catt S. , Kinder J. E. , Walton S. , Taylor-Robinson A. W.
Published: January 2019

Bovine invitro fertilisation technology has been widely exploited in commercial settings. The majority of invitro-derived cattle embryos are transferred into recipient cows as recently collected (i.e. ‘fresh’) embryos due to the lack of a reliable cryopreservation method that results in favourable pregnancy rates following transfer of thawed embryos. This is a primary reason for the poor industry uptake of this extreme temperature freezing process. Numerous investigations into vitrification have revealed the importance of rapid cooling and warming rates, enhancing embryo viability after cryopreservation compared with conventional slow freezing. Those studies spawned a considerable assortment of cryovessels and diversity of procedures, delivering variable rates of success, which makes performing vitrification consistently a practical challenge. Hence, further research is required in order to both optimise and standardise vitrification methodology and to design a cryovessel that enables direct transfer of vitrified embryos to recipients after warming. In parallel with improvements in vitrification, it is important to continue to raise the quality of invitro-derived cattle embryos through modifications in laboratory culture techniques. The twin goals of methodology refinement and standardisation, leading to embryo quality enhancement, are each imperative if invitro fertilisation technology is to be adopted in the field.
Global reconstruction of historical ocean heat storage and transport
Authors: Zanna Laure , Khatiwala Samar , Gregory Jonathan M. , Ison Jonathan , Heimbach Patrick
Published: January 2019

Significance

Since the 19th century, rising greenhouse gas concentrations have caused the ocean to absorb most of the Earth’s excess heat and warm up. Before the 1990s, most ocean temperature measurements were above 700 m and therefore, insufficient for an accurate global estimate of ocean warming. We present a method to reconstruct ocean temperature changes with global, full-depth ocean coverage, revealing warming of 436×1021J since 1871. Our reconstruction, which agrees with other estimates for the well-observed period, demonstrates that the ocean absorbed as much heat during 1921–1946 as during 1990–2015. Since the 1950s, up to one-half of excess heat in the Atlantic Ocean at midlatitudes has come from other regions via circulation-related changes in heat transport.
Risk-taking bias in human decision-making is encoded via a right–left brain push–pull system
Authors: Sacré Pierre , Kerr Matthew S. D. , Subramanian Sandya , Fitzgerald Zachary , Kahn Kevin , Johnson Matthew A. , Niebur Ernst , Eden Uri T. , González-Martínez Jorge A. , Gale John T. , Sarma Sridevi V.
Published: January 2019

Significance

Biases and fallacies can nudge humans in one direction or another as they make decisions. During gambling, bias is often generated by internal factors, including individual preferences, past experience, or emotions, and can move a person toward or away from risky behavior. The neural mechanisms responsible for generating internal bias are largely unknown, limiting the treatment of patients with neurological diseases that impair decision-making. We applied mathematical modeling techniques and high-resolution intracerebral recordings to uncover how a hidden internal bias builds up from past experiences to influence decisions and where this internal bias is encoded in the brain. Our findings suggest that biology exploits a distributed lateralized push–pull neural system to govern counterintuitive and highly variable decision-making in humans.
Socioecologically informed use of remote sensing data to predict rural household poverty
Authors: Watmough Gary R. , Marcinko Charlotte L. J. , Sullivan Clare , Tschirhart Kevin , Mutuo Patrick K. , Palm Cheryl A. , Svenning Jens-Christian
Published: January 2019

Significance

Understanding relationships between poverty and environment is crucial for sustainable development and ecological conservation. Annual monitoring of socioeconomic changes using household surveys is prohibitively expensive. Here, we demonstrate that satellite data predicted the poorest households in a landscape in Kenya with 62% accuracy. A multilevel socioecological treatment of satellite data accounting for the complex ways in which households interact with the environment provided better prediction than the standard single-buffer approach. The increasing availability of high-resolution satellite data and volunteered geographic data means this method could be modified and upscaled in the future to help monitor the sustainable development goals.
N-degron and C-degron pathways of protein degradation
Authors: Varshavsky Alexander
Published: January 2019

This perspective is partly review and partly proposal. N-degrons and C-degrons are degradation signals whose main determinants are, respectively, the N-terminal and C-terminal residues of cellular proteins. N-degrons and C-degrons include, to varying extents, adjoining sequence motifs, and also internal lysine residues that function as polyubiquitylation sites. Discovered in 1986, N-degrons were the first degradation signals in short-lived proteins. A particularly large set of C-degrons was discovered in 2018. We describe multifunctional proteolytic systems that target N-degrons and C-degrons. We also propose to denote these systems as “N-degron pathways” and “C-degron pathways.” The former notation replaces the earlier name “N-end rule pathways.” The term “N-end rule” was introduced 33 years ago, when only some N-terminal residues were thought to be destabilizing. However, studies over the last three decades have shown that all 20 amino acids of the genetic code can act, in cognate sequence contexts, as destabilizing N-terminal residues. Advantages of the proposed terms include their brevity and semantic uniformity for N-degrons and C-degrons. In addition to being topologically analogous, N-degrons and C-degrons are related functionally. A proteolytic cleavage of a subunit in a multisubunit complex can create, at the same time, an N-degron (in a C-terminal fragment) and a spatially adjacent C-degron (in an N-terminal fragment). Consequently, both fragments of a subunit can be selectively destroyed through attacks by the N-degron and C-degron pathways.
Disruption of RPGR protein interaction network is the common feature of RPGR missense variations that cause XLRP
Authors: Zhang Qihong , Giacalone Joseph C. , Searby Charles , Stone Edwin M. , Tucker Budd A. , Sheffield Val C.
Published: January 2019

Significance

Due to its severity and early onset, X-linked retinitis pigmentosa (XLRP) is a particularly devastating form of retinal degeneration. Most males with XLRP come to medical attention before the age of 20. Approximately 15% of all RP is X-linked, and more than 70% of these cases are caused by mutations in the
RPGR
gene. Currently, there is no known assay to evaluate the nature of RPGR missense variants functionally. In this study, we developed an in vitro assay to examine how different missense variations in
RPGR
cause XLRP. Our assay is based on the RPGR protein interaction network. Our method provides a cost-effective test for RPGR functional mutation analysis.
Deconstruction subtitled – Subtitling deconstructed
Authors: Jordà Mathiasen Eivor
Published: January 2019

Derrida revealed the fallacy that it is possible to distinguish between reality, thinking and language; a fallacy
constructed by Plato and transmitted through Western philosophy. Furthermore, this belief has been the foundation stone of
translation studies, creating a concept of translation as a mechanism by means of which the essence of a message is transmitted
from one language to another, and whose ultimate guarantor is always the author of the original text. Derrida makes use of writing
to dismantle this fallacy and to show language as a complex system of signs that do not have one fixed, unchangeable meaning,
insofar as they cannot actualize the referent, but rather imply a multiplicity of interpretations. In a multimodal context in
which the original and the translation are simultaneous and complementary, subtitling brings us closer to the Derridian notion of
writing as the place wherein language shows us precisely what it is.
A cellular complex of BACE1 and γ-secretase sequentially generates Aβ from its full-length precursor
Authors: Liu Lei , Ding Li , Rovere Matteo , Wolfe Michael S. , Selkoe Dennis J.
Published: January 2019

Intramembrane proteolysis of transmembrane substrates by the presenilin–γ-secretase complex is preceded and regulated by shedding of the substrate’s ectodomain by α- or β-secretase. We asked whether β- and γ-secretases interact to mediate efficient sequential processing of APP, generating the amyloid β (Aβ) peptides that initiate Alzheimer’s disease. We describe a hitherto unrecognized multiprotease complex containing active β- and γ-secretases. BACE1 coimmunoprecipitated and cofractionated with γ-secretase in cultured cells and in mouse and human brain. An endogenous high molecular weight (HMW) complex (∼5 MD) containing β- and γ-secretases and holo-APP was catalytically active in vitro and generated a full array of Aβ peptides, with physiological Aβ42/40 ratios. The isolated complex responded properly to γ-secretase modulators. Alzheimer’s-causing mutations in presenilin altered the Aβ42/40 peptide ratio generated by the HMW β/γ-secretase complex indistinguishably from that observed in whole cells. Thus, Aβ is generated from holo-APP by a BACE1–γ-secretase complex that provides sequential, efficient RIP processing of full-length substrates to final products.
On the quadratic dual of the Fomin–Kirillov algebras
Authors: Walton Chelsea , Zhang James
Published: January 2019

We study ring-theoretic and homological properties of the quadratic dual (or Koszul dual)

E

n
!

\mathcal {E}_n^!

of the Fomin–Kirillov algebras

E

n

\mathcal {E}_n

; these algebras are connected

N

\mathbb {N}

-graded and are defined for

n
≥
2

n \geq 2

. We establish that the algebra

E

n
!

\mathcal {E}_n^!

is module finite over its center (and thus satisfies a polynomial identity), is Noetherian, and has Gelfand–Kirillov dimension

⌊
n

/

2
⌋

\lfloor n/2 \rfloor

for each

n
≥
2

n \geq 2

. We also observe that

E

n
!

\mathcal {E}_n^!

is not prime for

n
≥
3

n \geq 3

. By a result of Roos,

E

n

\mathcal {E}_n

is not Koszul for

n
≥
3

n \geq 3

, so neither is

E

n
!

\mathcal {E}_n^!

for

n
≥
3

n \geq 3

. Nevertheless, we prove that

E

n
!

\mathcal {E}_n^!

is Artin–Schelter (AS-)regular if and only if

n
=
2

n=2

, and that

E

n
!

\mathcal {E}_n^!

is both AS-Gorenstein and AS-Cohen–Macaulay if and only if

n
=
2
,
3

n=2,3

. We also show that the depth of

E

n
!

\mathcal {E}_n^!

is

≤
1

\leq 1

for each

n
≥
2

n \geq 2

, conjecture that we have equality, and show that this claim holds for

n
=
2
,
3

n =2,3

. Several other directions for further examination of

E

n
!

\mathcal {E}_n^!

are suggested at the end of this article.
On pro-𝑝 link groups of number fields
Authors: Mizusawa Yasushi
Published: January 2019

As an analogue of a link group, we consider the Galois group of the maximal pro-

p
p

-extension of a number field with restricted ramification which is cyclotomically ramified at

p
p

, i.e., tamely ramified over the intermediate cyclotomic

Z

p

\mathbb Z_p

-extension of the number field. In some basic cases, such a pro-

p
p

Galois group also has a Koch type presentation described by linking numbers and mod

2
2

Milnor numbers (Rédei symbols) of primes. Then the pro-

2
2

Fox derivative yields a calculation of Iwasawa polynomials analogous to Alexander polynomials.
Characterizing and ranking computed metabolic engineering strategies
Authors: Schneider Philipp , Klamt Steffen
Published: January 2019

Motivation

The computer-aided design of metabolic intervention strategies has become a key component of an integrated metabolic engineering approach and a broad range of methods and algorithms has been developed for this task. Many of these algorithms enforce coupling of growth with product synthesis and may return thousands of possible intervention strategies from which the most suitable strategy must then be selected

Results

This work focuses on how to evaluate and rank, in a meaningful way, a given pool of computed metabolic engineering strategies for growth-coupled product synthesis. Apart from straightforward criteria, such as a preferably small number of necessary interventions, a reasonable growth rate and a high product yield, we present several new criteria useful to pick the most suitable intervention strategy. Among others, we investigate the robustness of the intervention strategies by searching for metabolites that may disrupt growth coupling when accumulated or secreted and by checking whether the interventions interrupt pathways at their origin (preferable) or at downstream steps. We also assess thermodynamic properties of the pathway(s) favored by the intervention strategy. Furthermore, strategies that have a significant overlap with alternative solutions are ranked higher because they provide flexibility in implementation. We also introduce the notion of equivalence classes for grouping intervention strategies with identical solution spaces. Our ranking procedure involves in total ten criteria and we demonstrate its applicability by assessing knockout-based intervention strategies computed in a genome-scale model of E.coli for the growth-coupled synthesis of l-methionine and of the heterologous product 1,4-butanediol.

Availability and implementation

The MATLAB scripts that were used to characterize and rank the example intervention strategies are available at http://www2.mpi-magdeburg.mpg.de/projects/cna/etcdownloads.html.

Supplementary information

Supplementary data are available at Bioinformatics online.
A web application and service for imputing and visualizing missense variant effect maps
Authors: Wu Yingzhou , Weile Jochen , Cote Atina G , Sun Song , Knapp Jennifer , Verby Marta , Roth Frederick P
Published: January 2019

The promise of personalized genomic medicine depends on our ability to assess the functional impact of rare sequence variation. Multiplexed assays can experimentally measure the functional impact of missense variants on a massive scale. However, even after such assays, many missense variants remain poorly measured. Here we describe a software pipeline and application to impute missing information in experimentally determined variant effect maps.

Availability and implementation

http://impute.varianteffect.org source code: https://github.com/joewuca/imputation.

Supplementary information

Supplementary data are available at Bioinformatics online.
Alterations in Oscillatory Behavior of Central Medial Thalamic Neurons Demonstrate a Key Role of CaV3.1 Isoform of T-Channels During Isoflurane-Induced Anesthesia
Authors: Timic Stamenic Tamara , Feseha Simon , Valdez Robert , Zhao Wanzhu , Klawitter Jost , Todorovic Slobodan M
Published: January 2019

Although the central medial nucleus (CeM) of the thalamus is an essential part of the arousal system for sleep and anesthesia initiation, the precise mechanisms that regulate its activity are not well studied. We examined the role of CaV3.1 isoform of T-type calcium channels (T-channels) in the excitability and rhythmic activity of CeM neurons during isoflurane (ISO)-induced anesthesia by using mouse genetics and selective pharmacology. Patch-clamp recordings taken from acute brain slices revealed that CaV3.1 channels in CeM are inhibited by prototypical volatile anesthetic ISO (250 and 500 μM) and selective T-channels blocker 3,5-dichloro-N-[1-(2,2-dimethyl-tetrahydro-pyran-4-ylmethyl)-4-fluoro-piperidin-4-ylmethyl]-benzamide (TTA-P2). Both TTA-P2 and ISO attenuated tonic and burst firing modes, and hyperpolarized CeM neurons from wild type (WT) mice. These effects were greatly diminished or abolished in CaV3.1 null mice. Our ensuing in vivo local field potential (LFP) recordings from CeM indicated that the ability of TTA-P2 and anesthetic concentrations of ISO to promote δ oscillation was substantially weakened in CaV3.1 null mice. Furthermore, escalating ISO concentrations induced stronger burst-suppression LFP pattern in mutant than in WT mice. Our results demonstrate for the first time the importance of CaV3.1 channels in thalamocortical oscillations from the non-specific thalamic nuclei that underlie clinically important effects of ISO.
Characterizing Dysgeusia in Hemodialysis Patients
Authors: Fitzgerald Ciara , Wiese Gretchen , Moorthi Ranjani N , Moe Sharon M , Hill Gallant Kathleen , Running Cordelia A
Published: January 2019

Dysgeusia (abnormal taste) is common in those with chronic kidney disease and contributes to poor nutritional intake. Previous sensory work has shown that taste improves after dialysis sessions. The goal of this pilot study was to characterize altered taste perceptions in patients on dialysis compared with healthy adults, and to evaluate relationships between serum parameters with taste perceptions. We hypothesized that patients undergoing dialysis would experience blunted taste intensities compared with controls, and that serum levels of potential tastants would be inversely related to taste perception of compounds. Using a cross-sectional design, we carried out suprathreshold sensory assessments (flavor intensity and liking) of tastants/flavors potentially influenced by kidney disease and/or the dialysis procedure. These included sodium chloride, potassium chloride, calcium chloride, sodium phosphate, phosphoric acid, urea, ferrous sulfate, and monosodium glutamate. Individuals on maintenance hemodialysis (n= 17, 10 males, range 23–87 years) were compared with controls with normal gustatory function (n=29, 13 males, range 21–61 years). Unadjusted values for intensity and liking for the solutions showed minimal differences. However, when values were adjusted for participants’ perceptions of water (as a control for taste abnormalities), intensity of monosodium glutamate, sodium chloride, and sodium phosphate solutions were more intense for patients on dialysis compared with controls. Some significant correlations were also observed between serum parameters, particularly potassium, for dialysis patients and sensory ratings. These results suggest altered taste perception in patients during dialysis warrants further study.
Antibiotic Resistance and Typhoid
Authors: Dyson Zoe A , Klemm Elizabeth J , Palmer Sophie , Dougan Gordon
Published: January 2019

Multiple drug (antibiotic) resistance (MDR) has become a major threat to the treatment of typhoid and other infectious diseases. Since the 1970s, this threat has increased in Salmonella enterica serovar Typhi, driven in part by the emergence of successful genetic clades, such as haplotype H58, associated with the MDR phenotype. H58 S. Typhi can express multiple antibiotic resistance determinants while retaining the ability to efficiently transmit and persist within the human population. The recent identification of extensively drug resistant S. Typhi only highlights the dangers of ignoring this threat. Here we discuss the evolution of the S. Typhi MDR phenotype and consider options for management.
Deaths From Plasmodium knowlesi Malaria: Case Series and Systematic Review
Authors: Rajahram Giri S , Cooper Daniel J , William Timothy , Grigg Matthew J , Anstey Nicholas M , Barber Bridget E
Published: January 2019

Background

Plasmodium knowlesi causes severe and fatal malaria, and incidence in Southeast Asia is increasing. Factors associated with death are not clearly defined.

Methods

All malaria deaths in Sabah, Malaysia, from 2015 to 2017 were identified from mandatory reporting to the Sabah Department of Health. Case notes were reviewed, and a systematic review of these and all previously reported fatal P. knowlesi cases was conducted. Case fatality rates (CFRs) during 2010–2017 were calculated using incidence data from the Sabah Department of Health.

Results

Six malaria deaths occurred in Sabah during 2015–2017, all from P. knowlesi. Median age was 40 (range, 23–58) years; 4 cases (67%) were male. Three (50%) had significant cardiovascular comorbidities and 1 was pregnant. Delays in administering appropriate therapy contributed to 3 (50%) deaths. An additional 26 fatal cases were included in the systematic review. Among all 32 cases, 18 (56%) were male; median age was 56 (range, 23–84) years. Cardiovascular-metabolic disease, microscopic misdiagnosis, and delay in commencing intravenous treatment were identified in 11 of 32 (34%), 26 of 29 (90%), and 11 of 31 (36%) cases, respectively. The overall CFR during 2010–2017 was 2.5/1000: 6.0/1000 for women and 1.7/1000 for men (P = .01). Independent risk factors for death included female sex (odds ratio, 2.6; P = .04), and age ≥45 years (odds ratio, 4.7; P < .01).

Conclusions

Earlier presentation, more rapid diagnosis, and administration of intravenous artesunate may avoid fatal outcomes, particularly in females, older adults, and patients with cardiovascular comorbidities.
Building consensus toward a national nursing home information technology maturity model
Authors: Alexander Gregory L , Powell Kimberly , Deroche Chelsea B , Popejoy Lori , Mosa Abu Saleh Mohammad , Koopman Richelle , Pettit Lorren , Dougherty Michelle
Published: January 2019

Objectives

We describe the development of a nursing home information technology (IT) maturity model designed to capture stages of IT maturity.

Materials and Methods

This study had 2 phases. The purpose of phase I was to develop a preliminary nursing home IT maturity model. Phase II involved 3 rounds of questionnaires administered to a Delphi panel of expert nursing home administrators to evaluate the validity of the nursing home IT maturity model proposed in phase I.

Results

All participants (n = 31) completed Delphi rounds 1-3. Over the 3 Delphi rounds, the nursing home IT maturity staging model evolved from a preliminary, 5-stage model (stages 1-5) to a 7-stage model (stages 0-6).

Discussion

Using innovative IT to improve patient outcomes has become a broad goal across healthcare settings, including nursing homes. Understanding the relationship between IT sophistication and quality performance in nursing homes relies on recognizing the spectrum of nursing home IT maturity that exists and how IT matures over time. Currently, no universally accepted nursing home IT maturity model exists to trend IT adoption and determine the impact of increasing IT maturity on quality.

Conclusions

A 7-stage nursing home IT maturity staging model was successfully developed with input from a nationally representative sample of U.S. based nursing home experts. The model incorporates 7-stages of IT maturity ranging from stage 0 (nonexistent IT solutions or electronic medical record) to stage 6 (use of data by resident or resident representative to generate clinical data and drive self-management).
Patient experience with family history tool: analysis of patients’ experience sharing their family health history through patient-computer dialogue in a patient portal
Authors: Bajracharya Adarsha S , Crotty Bradley H , Kowoloff Hollis B , Safran Charles , Slack Warner V
Published: January 2019

Objective

The collection and use of a family health history are important for assessing the patient’s risk of disease, but history taking is often impeded by practical barriers in the office. Provision for patient-computer dialogue, linked with the electronic health record, may enable patients to contribute their history while bypassing these barriers. We sought to assess the patient experience using such a tool.

Materials and Methods

We linked the family history module of a computer-based medical history to the patient portal of a large academic health system. The interview consisted of 39 primary questions with a predetermined high test-retest reliability. Patients’ results were structured and summarized, and available within their electronic health record. Patients optionally completed a survey about their experience. We inductively analyzed free-text responses collected between 2014 and 2016.

Results

Among 97 781 patient portal users, 9562 patients accessed and 4223 patients completed the family medical history interview. Of these patients, 1451 completed our survey. Main themes that were identified included (1) patient empowerment, (2) anticipated value, (3) validity concerns, (4) privacy concerns, and (5) reflections on patient-computer dialogue. Patients also provided suggestions for the improvement of future family history tools.

Discussion

Patients providing their family health information is an example of collaborative electronic work with clinicians and was seen as valuable by those who participated. Concerns related to contextual information and uncertainty need to be addressed.

Conclusions

Patient-computer dialogue to collect family medical history empowered patients and added perceived value and efficiency to the patient experience of care.
Pathways for African American Success: Results of Three-Arm Randomized Trial to Test the Effects of Technology-Based Delivery for Rural African American Families
Authors: Murry Velma McBride , Berkel Cady , Inniss-Thompson Misha N , Debreaux Marlena L
Published: January 2019

Objective

The objective of this study was to test the effectiveness of a technology-based program to avert risky behaviors among rural African American youth. We hypothesized that the technology-based and group-based formats of the Pathways for African Americans Success (PAAS) program would lead to improvements in primary outcomes, and that the technology condition would perform at least as well as the group condition.

Methods

A three-arm Randomized Control Trial (RCT) ([N = 141] technology-based delivery, [N = 141] small group delivery, and [N = 136] literature control) was conducted with 421 sixth graders and their caregivers, Summer 2009–Fall 2012. Families were recruited from five rural counties in Tennessee and completed baseline, posttest [M = 14.5 (4.4) months after pretest] and long-term follow-up [M = 22.6 (3.7) months after posttest]. Structural Equation Modeling (SEM) was used to test intervention-induced changes in both parents and youths’ primary outcomes (pretest to posttest) and on secondary targeted outcome, youth sexual risk, and substance use patterns (pretest to follow-up).

Results

Parents in the technology condition reported significant increases in strategies to reduce risk. Youth in the technology condition experienced a significant decline in intent to engage in risk behaviors and reduction in substance use and sexual risk behavior. Youth in the group condition experienced a significant increase in affiliation with deviant peers.

Conclusions

This study provides evidence of the ability of eHealth to improve parenting and reduce adolescent engagement in substance use and sexual risk behavior. Suggestions for dissemination in schools and health-care systems are offered.
Conflicts and Relative Deprivation in Ein El Hilweh: Palestinian Refugees in the Shadow of the Syrian Civil War
Authors: Nilsson Marco , Badran Dany
Published: January 2019

About 450,000 Palestinian refugees live in Lebanon today. With the arrival of over 1 million Syrian refugees in Lebanon since the Syrian civil war started in 2011, Palestinians were no longer the largest refugee group in Lebanon, and many newcomers settled in Palestinian refugee camps. Previous research has considered how recipient societies relate to refugees; this study analyses inter-group competition and conflict among refugees from different countries by analysing Palestinians’ perceptions of refugee camp life and attitudes towards Syrian refugees. Focus-group interviews were conducted in the largest camp in Lebanon, Ein El Hilweh. Respondents experienced relative deprivation due to the influx of Syrian refugees, who were accused of taking Palestinian jobs and increasing poverty. Respondents complained of increasing violence and social problems (e.g. radicalization and drug use) due to the demographic changes. Especially women experienced that their freedom of movement had become limited in the camp but found it difficult to consider migration. Increasing desperation had also weakened Palestinian resistance identity and trust in resistance organizations.