bluuebunny/crossref_metadata_2025 huggingface dataset:
Multi-objective optimization and experimental study of the milling parameters of cycloid gear
Authors: Xu JianMin , Gu Lizhi , Luo Shanming
Published: August 2020

To improve production efficiency and reduce machining cost of end milling cycloid gear, a multi-objective milling parameter optimization method which is based on the dynamic characteristics of the machining system is proposed. Using optimized milling parameters for finishing milling cycloid gear, the maximum tool tip deformation is reduced from 0.258μm to 0.092μm by 64.3%, the material removal rate is reduced from 1.56 cm3/mm to 1 cm3/mm by 35.9%, the tool life and the machining accuracy are significantly improved. Effectiveness of the milling parameter optimization model for cycloid gear is verified by milling experiments.
Experimental Research on Milling Temperature of New Cold Saw Blade Milling Cutter
Authors: Shuailiang Guo , Lizhi Gu , Jinling Song
Published: August 2020

Based on the orthogonal test method and comparative study, the effects of workpiece material, workpiece diameter, milling cutter rotational speed and feed per tooth on milling temperature are investigated when cutting metal bars with new cold saw blade milling cutter. Then this paper reveals the change rule of new cold saw blade milling cutter milling temperature and the essential difference from the traditional hot saw blade milling cutter. Construction of sawing metal bar experiment system at production site, four-factor and three-level orthogonal test method is used to cut 45 steel, 40Cr and Q235B metal materials. The influence curves of workpiece material, workpiece diameter, milling cutter rotational speed and feed per tooth on milling temperature are obtained. By normalizing the experimental data, this paper uses the multiple linear regression method to fit the mathematical model of milling temperature. According to simulation analysis and experimental research, the milling temperature change rule of new cold saw blade milling cutter is obtained. Compared with the traditional hot saw blade milling cutter, the results show that under the same or similar conditions, the highest milling temperature center of new cold saw blade milling cutter is located at the bottom of the chip at a certain distance from the tip and the interface of the corresponding cutting layer adjacent to the bottom layer of the chip. The maximum milling temperature is around 300 °C, which is about 175 °C lower than the maximum milling temperature of traditional hot saw blade milling cutter. Further, it demonstrates that most of the heat generated by cold sawing is discharged from the cutting area along with chips, which keeps the milling cutter and workpiece at a relatively low temperature.
Effect of HIP treatment on the microstructure and mechanical properties of a Ni-based superalloy fabricated by selective laser melted method
Authors: Guo Xiaojun , Ling Huixiang , Huang Xiaozhong
Published: August 2020

Selective laser melting (SLM) is one of the most emerging additive manufacturing (AM) method through the melting of metal powder to manufacture the full density parts, which will lead to an orientation microstructure and anisotropy mechanical properties. Thus, corresponding post-processing treatments, such as solution treatment (ST) and hot isostatic pressing (HIP), were subjected to the specimens before tests. The effect of the HIP on the microstructure and mechanical properties of SLM Inconel 625 was investigated through uniaxial tension tests at room and elevated temperature. The fracture mechanism was systematically characterized and analyzed using scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). It was found that the microstructure after the HIP process is composed of equiaxed austenite, and the annealing twins are reduced. The tensile test results reveal that the HIP has a significant impact on the plastic behavior of the alloy at high-temperature, and is the main reason for the greatly improved elongation, compared to the ST process.
Study on dynamic compression behavior and energy absorption characteristics of three negative Poisson’s ratio materials under different velocities
Authors: Wang GuoShu , Liu GuiFeng
Published: August 2020

This paper uses finite element analysis to study the impact dynamics of three negative Poisson’s ratio materials. Different Poisson’s ratio generation mechanisms, deformation modes, and dynamic response characteristics of three materials at different impact speeds are discussed. The unique necking phenomenon, the deformation mode diagram, dynamic response curve, and energy absorption curve are obtained after processing. The results of numerical simulations have deepened our understanding of negative Poisson’s ratio honeycomb materials, and have guiding significance for us to explore new high-performance honeycomb materials later.
Heat conduction mechanism in silica aerogel skeleton
Authors: Luo Z Y , Su G H , Yang Z C
Published: August 2020

In order to study the specific heat conduction process of silica aerogels, a three-dimensional random fractal skeleton model of aerogels was generated by using the diffusion-limited cluster aggregation (DLCA) method to simulate the gel process. Based on the idea of finite volume method, a numerical model of heat conduction in porous framework was established and verified. The three-dimensional temperature field and apparent thermal conductivity of the skeleton were calculated. The results show that when the initial particle concentration is 0.0764 ~ 0.191, the fractal dimension range of the skeleton model is 2.0 ~ 2.45, which is consistent with the measured value. However, in the plane perpendicular to the heat flow direction, the particle temperature is not exactly the same, which can be approximately described by normal distribution. The apparent thermal conductivity of the skeleton is three orders of magnitude lower than that of the bulk material, which can be attributed to its open form network structure.
Simulation Study of Micro Interface Damage of Particle Reinforced Metal Matrix Composites on Vibration Cutting
Authors: Yang Liang , Xu Chunguang , Wang Zhengjiang
Published: August 2020

The finite element simulation of the micro interface of SiCp/Al composites under ultrasonic vibration cutting is described. The constitutive relationship of the matrix, SiC particles and interface is analyzed respectively, and a “matrix-interface-particle” dynamic physical simulation model is given. The cutting conditions of a single particle in three different cutting paths are simulated, and the removal mechanism and interface damage characteristics of SiC particles is analyzed. The reliability of the simulation results is analyzed by observing the SEM photos of the experimental samples.
Experimental study of one-part geopolymer using different alkali sources
Authors: Ouyang Shuntian , Chen Weiquan , Zhang Zongtang , Li Xinming , Zhu Wenfeng
Published: August 2020

This paper investigates the feasibility of combining different solid alkali materials as activator to prepare one-part geopolymer mortars. The effects of different composite solid activators on aluminosilicate materials were studied and compared with the traditional water glass and sodium hydroxide composite solution activator through the measurement of fresh and harden properties and microstructural analysis. The results showed that sodium metasilicate pentahydrate was more suitable than quick-dissolving sodium silicate for preparation of geopolymer. The addition of sodium carbonate and calcium hydroxide in solid activator enhanced the compressive strength and decreased the setting time and flowability of the mixes. The highest compressive strength (47.4 MPa, 28 d) was obtained with the activators consisting of sodium metasilicate pentahydrate and sodium carbonate. While scanning electron microscope (SEM) analysis indicated that micro-pores left by the dissolution of metasilicate particles might have an adverse effect on the mechanical properties of mortar samples.
Experimental study on high-temperature stability of rubber powder-modified Asphalt mixture
Authors: Sun Jie , Wei Bingyan , Zhang Yao , Yang Jing
Published: August 2020

Waste rubber powder-modified asphalt can not only improve the asphalt pavement performance but can also solve the environmental pollution problem caused by waste tires. In this paper, through rutting tests, the effects of three different factors, the rubber powder content, rubber powder mesh number, and hydrogen peroxide content, on high-temperature stability of the mixture are systematically studied. The results reveal that the optimum rubber powder mesh is 60 mesh and the best rubber powder content is 21% for high-temperature stability of a rubber-modified asphalt mixture. At the same time, hydrogen peroxide can improve the high-temperature stability of the asphalt mixture.
Synthesis and properties of Ni-doped carbon aerogel
Authors: Wang Shasha , Zhang Lihui , Liu Zhenfa
Published: August 2020

Ni-doped carbon aerogels were synthesized by impregnation methods, their physical structure and surface morphology were studied. The results show that adding Ni is beneficial to increase the specific surface area of CA, but too much Ni will block some holes. The SEM images possess closer network structure and excellent connectivity. The XRD and Raman patterns show the addition of Ni can enhance the graphitization degree of carbon aerogels.
Size dependent photoelectrochemical performance of eco-friendly CuInS2 quantum dots
Authors: Wang Changmeng
Published: August 2020

Colloidal quantum dots (QDs) are considered as new energy materials with great potential, especially environmentally friendly QDs that do not contain heavy metals. Compared with heavy metal QDs, non-toxic QDs still suffer low performance in photovoltaic (PV) as well as photoelectrochemical (PEC) applications. The fabrication of high-performance PV devices from environmentally friendly QDs has become the focus of researchers. Before moving to experiments, the theoretical aspect is a very good way to deeply understand the charge carrier dynamics inside the QDs, which can provide possible solutions to improve the PEC performance of the QDs based photoelectrodes. Here, we report the successful synthesis of eco-friendly CuInS2(CIS) QDs with variable particle size. Through time-domain PL spectroscopy, we found that the photoluminescence (PL) lifetime gradually decreased from 273.2 ns to 172.9 ns as the size of CIS QDs increased. By theoretical calculations we also studied the dynamics of electrons and holes. The theoretical studies revealed that as the size of CIS QDs increases, the wave functions of the overlap between the electron and impurity hole increases leading to the decreased PL lifetime.
Enhancing the electrochemical performance of LiNi0.5Mn1.5O4 by V2O5-modification for Li-ion batteries
Authors: Wei Aijia , He Rui , Zhang Lihui , Liu Zhenfa
Published: August 2020

The 2 wt.% V2O5-modified LiNi0.5Mn1.5O4 material has been prepared by a sol-gel method. The as-prepared samples were characterized by XRD and SEM. XRD result shows V2O5-modification process did not destroy the structure of spinel LNMO. The electrochemical results show that the 2 wt.% V2O5-modified LiNi0.5Mn1.5O4 sample exhibits a higher rate performance with discharge capacities of 133.3, 131.3, 129.8, 125.8, 120.1, 103.2, and 79.0 mAh g−1 at 0.2, 0.5, 1, 2, 3, 5, and 7 C, respectively. Moreover, the 2 wt.% V2O5-modified LiNi0.5Mn1.5O4 provides an enhanced discharge capacity of 116.2 mAh g−1 after 200 cycles at 1 C, having a capacity retention of 91.6%, high than that of pure LNMO with a discharge capacity of 103.0 mAh g−1 and capacity retention of 85.3%.
Contact surface roughness analysis of pile and soil using ABS 3D printing materials
Authors: Sun Tingting , Yang Jixin , Zhang Zhihua , Yang Jingnan , Zhang Xuan , Ling Zhongshui
Published: August 2020

It is more difficult to measure the side resistance of the soil-structure contact surface during the pile pulling process. Only overcome the side resistance can be pulled out smoothly on the pile. Three kinds of test specimens were printed out by 3D printing equipment of the Acrylonitrile Butadiene Styrene (ABS) material to simulate the roughness of the soil-structure interface. The basic physical properties of two types of soil under the geological conditions of the pile to be pulled are tested through the geotechnical test, and the soil-structure constitutive theory and the roughness theory are introduced. The distribution of maximum shear stress at the contact surface is obtained by direct shear tests on the test specimens with different roughness, and the shear stage is analyzed with the contact surface. The results demonstrate that the mechanical properties of yellow clay are better than black clay for the two types of soil on the pile side. The shear stress changes with the increase of roughness and normal load during the direct shear process, which the maximum values of the two types of soil are at 60% of roughness and 300 kPa of normal load.
Co2P Embedded into P and N Dual-Doped Carbon Nanotubes and Graphene as a Bifunctional Oxygen Electrocatalyst
Authors: Shao Q , Wang H G , Duan Q
Published: August 2020

The reasonable design of inexpensive and efficient bifunctional electrocatalyst towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is still challenging for Zn-air batteries. Herein, a novel and effective design is proposed to fabricate Co2P nanoparticles encapsulated in doped carbon nanotubes and rGO sheets (Co2P/NPCNTs-rGO) through a direct self-catalyzed growth procedure. That is, cobalt phthalocyanine derivatives as the cobalt sources are not only employed to form Co2P nanoparticles, but also used to catalyze the formation of CNTs and rGO. Benefiting from the unique structure and composition, the Co2P/NPCNTs-rGO-800 shows significant OER (overpotential of 420 mV) and ORR (half-wave potential of 0.73 V) properties. Most importantly, the activity parameter of Co2P/NPCNTs-rGO-800 (ΔE=0.92 V) is comparable to that of RuO2(0.91 V) and lower than that of Pt/C (1.05 V), indicating that Co2P/NPCNTs-rGO-800 is of a good comprehensive ORR/OER bifunctional performance. This work provides an effective strategy for the synthesis of outstanding multifunctional catalysts for wider practical applications.
Conjugated Cobalt (II) Polyphthalocyanine Doped with Carbon Nanotubes as Available Electrode for Supercapacitors
Authors: Mei L , Wang H G , Duan Q
Published: August 2020

The use of organic compounds to meet the growing demand for new energy storage systems has attracted great attention, because they have the advantages of abundant resources, flexibility, and sustainability, which can be used as supercapacitor electrode materials. In this work, based on the synthetic metal polyphthalocyanine, carbon nanotube-doped conjugated cobalt (II)-polyphthalocyanine film was further used as an electrode material for supercapacitors. The results show that the obtained CoPPc-CNT has good electrochemical performance. The results show that by combining an organic material with a carbon matrix to prepare a composite material, the electronic conductivity can be effectively improved for supercapacitors.
Zein/phenolic antioxidant nanoparticles stabilized Pickering emulsions: Effect of antioxidant hydrophobicity on lipid oxidation
Authors: Zhao Zijun , Xiao Jie , Wang Wenbo , Cao Yong
Published: August 2020

Due to the presence of oils and fats, emulsions undergo lipid oxidation during storage, resulting in deterioration in sensory and nutritional qualities of emulsions. Phenolic antioxidants are widely used in inhibiting lipid oxidation. We found that phenolic antioxidants could form composite nanoparticles with zein and could be utilized to prepare Pickering emulsions with strong oxidative stability. Phenolic antioxidants with different hydrophobicity (octyl gallate, Propyl gallate and gallic acid) were fabricated into nanoparticles with zein (namely, Z/OG, Z/PG, Z/GA), and the oxidative stability of the as-prepared emulsions were much stronger than Tween 20 stabilized emulsions. And the Z/OG stabilized emulsions showed stronger oxidative stability than those stabilized by Z/PG and Z/GA. We also found that the antioxidative efficiency of octyl gallate was significantly higher than propyl gallate and gallic acid in Tween 20 stabilized emulsions. Compared with the Tween 20 stabilized emulsions, the difference in antioxidation efficiency between octyl gallate, propyl gallate and gallic acid was more obvious in the Pickering emulsions due to the combined effect of physical barrier and phenolic antioxidants. The results of this study help us to improve the antioxidant efficiency of phenolic antioxidants via the rational selection of antioxidant and a well-designed Pickering stabilization strategy.
Influences of four kinds of calcium salts on the functional performances of gelatin composite films
Authors: Yu Hong , Lin Wenxing , Yu Peng
Published: August 2020

Fish gelatin films were prepared with gelatin as the main raw material and four kinds of salts, including CaCl2, CaSO4, hydroxyapatite and Ca3(PO4)2, as the auxiliary reagents. The types of the anions and the concentrations of the calcium salts could affect the light transmission, swelling ratio, tensile strength, and elongation at break of gelatin films. The relationship between them was studied in this paper. The experimental data were analyzed and it is noted that the swelling ratio of the gelatin film was improved after adding the calcium salts. The swelling ratio of the hydroxyapatite/gelatin composite film was significantly bigger than that of other composite films. There is no significant effect on the light transmittance of the gelatin film after adding the calcium salts. The improved mechanical performances were found in the composite gelatin films by adding calcium chloride, calcium sulfate, and calcium phosphate. In comparison, calcium phosphate performed the greatest influence on improving the mechanical performances of the composite films.
Reconstructing full-field flapping wing dynamics from sparse measurements
Authors: Johns William , Davis Lisa , Jankauski Mark
Published: August 2020

Flapping insect wings deform during flight. This deformation benefits the insect’s aerodynamic force production as well as energetic efficiency. However, it is challenging to measure wing displacement field in flying insects. Many points must be tracked over the wing’s surface to resolve its instantaneous shape. To reduce the number of points one is required to track, we propose a physics-based reconstruction method called system equivalent reduction expansion processes to estimate wing deformation and strain from sparse measurements. Measurement locations are determined using a weighted normalized modal displacement method. We experimentally validate the reconstruction technique by flapping a paper wing from 5–9 Hz with 45° and measuring strain at three locations. Two measurements are used for the reconstruction and the third for validation. Strain reconstructions had a maximal error of 30% in amplitude. We extend this methodology to a more realistic insect wing through numerical simulation. We show that wing displacement can be estimated from sparse displacement or strain measurements, and that additional sensors spatially average measurement noise to improve reconstruction accuracy. This research helps overcome some of the challenges of measuring full-field dynamics in flying insects and provides a framework for strain-based sensing in insect-inspired flapping robots.
𝐾-theory and topological cyclic homology of henselian pairs
Authors: Clausen Dustin , Mathew Akhil , Morrow Matthew
Published: August 2020

Given a henselian pair

(
R
,
I
)

(R, I)

of commutative rings, we show that the relative

K
K

-theory and relative topological cyclic homology with finite coefficients are identified via the cyclotomic trace

K
→

T
C

K \to \mathrm {TC}

. This yields a generalization of the classical Gabber–Gillet–Thomason–Suslin rigidity theorem (for mod

n
n

coefficients, with

n
n

invertible in

R
R

) and McCarthy’s theorem on relative

K
K

-theory (when

I
I

is nilpotent).

We deduce that the cyclotomic trace is an equivalence in large degrees between

p
p

-adic

K
K

-theory and topological cyclic homology for a large class of

p
p

-adic rings. In addition, we show that

K
K

-theory with finite coefficients satisfies continuity for complete noetherian rings which are

F
F

-finite modulo

p
p

. Our main new ingredient is a basic finiteness property of

T
C

\mathrm {TC}

with finite coefficients.
A note on devising HDG+ projections on polyhedral elements
Authors: Du Shukai , Sayas Francisco-Javier
Published: August 2020

In this paper, we propose a simple way of constructing HDG+ projections on polyhedral elements. The projections enable us to analyze the Lehrenfeld–Schöberl HDG (HDG+) methods in a very concise manner, and make many existing analysis techniques of standard HDG methods reusable for HDG+. The novelty here is an alternative way of constructing the projections without using

M
M

-decompositions as a middle step. This extends our previous results [S. Du and F.-J. Sayas, SpringerBriefs in Mathematics (2019)] (elliptic problems) and [S. Du and F.-J. Sayas, Math. Comp. 89 (2020), pp. 1745–1782] (elasticity) to polyhedral meshes.
The smallest prime in a conjugacy class and the first sign change for automorphic 𝐿-functions
Authors: Cho Peter , Kim Henry
Published: August 2020

Let

K
K

be an

S
n

S_n

-field. For a nonidentity conjugacy class

C
C

, define

N

K
,
C

N_{K,C}

to be the smallest prime

p
p

such that Frob

p

∈
C

_p\in C

. By using the observation that

N

K
,
C

N_{K,C}

is interpreted as the first prime sign change of the Dirichlet coefficients of automorphic

L
L

-functions, we improve the known bound on

N

K
,
C

N_{K,C}

for

n
=
3
,
4
,
5

n=3,4,5

. (For

n
=
5

n=5

, we need to assume the strong Artin conjecture.)
Horizontal Egorov property of Riesz spaces
Authors: Popov Mikhail
Published: August 2020

We say that a Riesz space

E
E

has the horizontal Egorov property if for every net

(

f
α

)

(f_\alpha )

in

E
E

, order convergent to

f
∈
E

f \in E

with

|

f
α

|

+

|

f

|

≤
e
∈

E
+

|f_\alpha | + |f| \le e \in E^+

for all

α
\alpha

, there exists a net

(

e
β

)

(e_\beta )

of fragments of

e
e

laterally convergent to

e
e

such that for every

β
\beta

, the net

(

|

f
−

f
α

|

∧

e
β

)

α

\bigl (|f - f_\alpha | \wedge e_\beta \bigr )_\alpha

e
e

-uniformly tends to zero. Our main result asserts that every Dedekind complete Riesz space which satisfies the weak distributive law possesses the horizontal Egorov property. A Riesz space

E
E

is said to satisfy the weak distributive law if for every

e
∈

E
+

∖
{
0
}

e \in E^+ \setminus \{0\}

the Boolean algebra

F

e

\mathfrak {F}_e

of fragments of

e
e

satisfies the weak distributive law; that is, whenever

(

Π
n

)

n
∈

N

(\Pi _n)_{n \in \mathbb N}

is a sequence of partitions of

F

e

\mathfrak {F}_e

, there is a partition

Π
\Pi

of

F

e

\mathfrak {F}_e

such that every element of

Π
\Pi

is finitely covered by each of

Π
n

\Pi _n

(e.g., every measurable Boolean algebra is so). Using a new technical tool, we show that for every net

(

f
α

)

(f_\alpha )

order convergent to

f
f

in a Riesz space with the horizontal Egorov property there are a horizontally vanishing net

(

v
β

)

(v_\beta )

and a net

(

u

α
,
β

)

(
α
,
β
)
∈
A
×
B

(u_{\alpha , \beta })_{(\alpha , \beta ) \in A \times B}

, which uniformly tends to zero for every fixed

β
\beta

such that

|

f
−

f
α

|

≤

u

α
,
β

+

v
β

|f - f_\alpha | \le u_{\alpha , \beta } + v_\beta

for all

α
,
β

\alpha , \beta

.
The Splitting Theorem and topology of noncompact spaces with nonnegative N-Bakry Émery Ricci curvature
Authors: Lim Alice
Published: August 2020

In this paper, we generalize topological results known for noncompact manifolds with nonnegative Ricci curvature to spaces with nonnegative

N
N

-Bakry Émery Ricci curvature. We study the Splitting Theorem and a property called the geodesic loops to infinity property in relation to spaces with nonnegative

N
N

-Bakry Émery Ricci curvature. In addition, we show that if

M
n

M^n

is a complete, noncompact Riemannian manifold with nonnegative

N
N

-Bakry Émery Ricci curvature where

N
>
n

N>n

, then

H

n
−
1

(
M
,

Z

)

H_{n-1}(M,\mathbb {Z})

is

0
0

.
A counterexample to 𝐶^{𝑘}-regularity for the Newlander-Nirenberg theorem
Authors: Yao Liding
Published: August 2020

We give an example of a

C
k

C^k

-integrable almost complex structure that does not admit a corresponding

C

k
+
1

C^{k+1}

-complex coordinate system.
Invariable generation of certain groups of piecewise linear homeomorphisms of the interval
Authors: Matsuda Yoshifumi , Matsumoto Shigenori
Published: August 2020

Let

P
P

be the group of all the orientation preserving piecewise linear homeomorphisms of the interval

[
0
,
1
]

[0,1]

. Given any

a
>
1

a>1

, let

P
a

P^a

be the subgroup of

P
P

consisting of all the elements with slopes in

a

Z

a^\mathbb {Z}

, and let

P

Q

P^\mathbb {Q}

be the subgroup of

P
P

consisting of all the elements with slopes and breaks in

Q

\mathbb {Q}

. We show that the groups

P
P

,

P
a

P^a

,

P

Q

P^\mathbb {Q}

, as well as Thompson group

F
F

, are invariably generated.
Congruences satisfied by eta-quotients
Authors: Ryan Nathan , Scherr Zachary , Sirolli Nicolás , Treneer Stephanie
Published: August 2020

The values of the partition function, and more generally the Fourier coefficients of many modular forms, are known to satisfy certain congruences. Results given by Ahlgren and Ono for the partition function and by Treneer for more general Fourier coefficients state the existence of infinitely many families of congruences. In this article we give an algorithm for computing explicit instances of such congruences for eta-quotients. We illustrate our method with a few examples.
Unbalanced polarized relations
Authors: Garti Shimon
Published: August 2020

We prove the consistency of the relation(μ+μ)↛(μ+ ω1μμ)\binom {\mu ^+}{\mu }\nrightarrow \binom {\mu ^+\ \omega _1}{\mu \quad \mu }whereμ\muis a strong limit singular cardinal of countable cofinality. This result can be forced atμ=ℵω\mu =\aleph _\omega.
Bernstein-Sato theory for arbitrary ideals in positive characteristic
Authors: Quinlan-Gallego Eamon
Published: August 2020

Mustaţă defined Bernstein-Sato polynomials in prime characteristic for principal ideals and proved that the roots of these polynomials are related to the

F
F

-jumping numbers of the ideal. This approach was later refined by Bitoun. Here we generalize these techniques to develop analogous notions for the case of arbitrary ideals and prove that these have similar connections to

F
F

-jumping numbers.
Higher-Order Evidence
Authors: Whiting Daniel
Published: August 2020

A critical survey of recent work in epistemology on higher-order evidence. It discusses the nature of higher-order evidence, some puzzles it raises, responses to those puzzles, and problems facing them. It concludes by indicating connections between debates concerning higher-order evidence in epistemology and parallel debates in ethics and aesthetics.
A proteomic analysis of grain yield-related traits in wheat
Authors: Daba Sintayehu D , Liu Xiaoqin , Aryal Uma , Mohammadi Mohsen
Published: August 2020

Grain yield, which is mainly contributed by tillering capacity as well as kernel number and weight, is the most important trait to plant breeders and agronomists. Label-free quantitative proteomics was used to analyse yield-contributing organs in wheat. These were leaf sample, tiller initiation, spike initiation, ovary and three successive kernel development stages at 5, 10 and 15 days after anthesis (DAA). We identified 3182 proteins across all samples. The largest number was obtained for spike initiation (1673), while the smallest was kernel sample at 15 DAA (709). Of the 3182 proteins, 296 of them were common to all seven organs. Organ-specific proteins ranged from 148 in ovary to 561 in spike initiation. When relative protein abundances were compared to that of leaf sample, 347 and 519 proteins were identified as differentially abundant in tiller initiation and spike initiation, respectively. When compared with ovary, 81, 35 and 96 proteins were identified as differentially abundant in kernels sampled at 5, 10 and 15 DAA, respectively. Our study indicated that two Argonaute proteins were solely expressed in spike initiation. Of the four expansin proteins detected, three of them were mainly expressed during the first 10 days of kernel development after anthesis. We also detected cell wall invertases and sucrose and starch synthases mainly during the kernel development period. The manipulation of these proteins could lead to increases in tillers, kernels per spike or final grain weight, and is worth exploring in future studies.
Pollinators drive floral evolution in an Atlantic Forest genus
Authors: Neves Beatriz , Kessous Igor M , Moura Ricardo L , Couto Dayvid R , Zanella Camila M , Antonelli Alexandre , Bacon Christine D , Salgueiro Fabiano , Costa Andrea F
Published: August 2020

Pollinators are important drivers of angiosperm diversification at both micro- and macroevolutionary scales. Both hummingbirds and bats pollinate the species-rich and morphologically diverse genus Vriesea across its distribution in the Brazilian Atlantic Forest. Here, we (i) determine if floral traits predict functional groups of pollinators as documented, confirming the pollination syndromes in Vriesea and (ii) test if genetic structure in Vriesea is driven by geography (latitudinal and altitudinal heterogeneity) or ecology (pollination syndromes). We analysed 11 floral traits of 58 Vriesea species and performed a literature survey of Vriesea pollination biology. The genealogy of haplotypes was inferred and phylogenetic analyses were performed using chloroplast (rps16-trnk and matK) and nuclear (PHYC) molecular markers. Floral traits accurately predict functional groups of pollinators in Vriesea. Genetic groupings match the different pollination syndromes. Species with intermediate position were found between the groups, which share haplotypes and differ morphologically from the typical hummingbird- and bat-pollinated flowers of Vriesea. The phylogeny revealed moderately to well-supported clades which may be interpreted as species complexes. Our results suggest a role of pollinators driving ecological isolation in Vriesea clades. Incipient speciation and incomplete lineage sorting may explain the overall low genetic divergence within and among morphologically defined species, precluding the identification of clear species boundaries. The intermediate species with mixed floral types likely represent a window into shifts between pollinator syndromes. This study reports the morphological-genetic continuum that may be typical of ongoing pollinator-driven speciation in biodiversity hotspots.
SOLQC: Synthetic Oligo Library Quality Control tool
Authors: Sabary Omer , Orlev Yoav , Shafir Roy , Anavy Leon , Yaakobi Eitan , Yakhini Zohar
Published: August 2020

Motivation

Recent years have seen a growing number and an expanding scope of studies using synthetic oligo libraries for a range of applications in synthetic biology. As experiments are growing by numbers and complexity, analysis tools can facilitate quality control and support better assessment and inference.

Results

We present a novel analysis tool, called SOLQC, which enables fast and comprehensive analysis of synthetic oligo libraries, based on NGS analysis performed by the user. SOLQC provides statistical information such as the distribution of variant representation, different error rates and their dependence on sequence or library properties. SOLQC produces graphical reports from the analysis, in a flexible format. We demonstrate SOLQC by analyzing literature libraries. We also discuss the potential benefits and relevance of the different components of the analysis.

Availability and implementation

SOLQC is a free software for non-commercial use, available at https://app.gitbook.com/@yoav-orlev/s/solqc/. For commercial use please contact the authors.

Supplementary information

Supplementary data are available at Bioinformatics online.
DELPHI: accurate deep ensemble model for protein interaction sites prediction
Authors: Li Yiwei , Golding G Brian , Ilie Lucian
Published: August 2020

Motivation

Proteins usually perform their functions by interacting with other proteins, which is why accurately predicting protein–protein interaction (PPI) binding sites is a fundamental problem. Experimental methods are slow and expensive. Therefore, great efforts are being made towards increasing the performance of computational methods.

Results

We propose DEep Learning Prediction of Highly probable protein Interaction sites (DELPHI), a new sequence-based deep learning suite for PPI-binding sites prediction. DELPHI has an ensemble structure which combines a CNN and a RNN component with fine tuning technique. Three novel features, HSP, position information and ProtVec are used in addition to nine existing ones. We comprehensively compare DELPHI to nine state-of-the-art programmes on five datasets, and DELPHI outperforms the competing methods in all metrics even though its training dataset shares the least similarities with the testing datasets. In the most important metrics, AUPRC and MCC, it surpasses the second best programmes by as much as 18.5% and 27.7%, respectively. We also demonstrated that the improvement is essentially due to using the ensemble model and, especially, the three new features. Using DELPHI it is shown that there is a strong correlation with protein-binding residues (PBRs) and sites with strong evolutionary conservation. In addition, DELPHI’s predicted PBR sites closely match known data from Pfam. DELPHI is available as open-sourced standalone software and web server.

Availability and implementation

The DELPHI web server can be found at delphi.csd.uwo.ca/, with all datasets and results in this study. The trained models, the DELPHI standalone source code, and the feature computation pipeline are freely available at github.com/lucian-ilie/DELPHI.

Supplementary information

Supplementary data are available at Bioinformatics online.
STACAS: Sub-Type Anchor Correction for Alignment in Seurat to integrate single-cell RNA-seq data
Authors: Andreatta Massimo , Carmona Santiago J
Published: August 2020

STACAS is a computational method for the identification of integration anchors in the Seurat environment, optimized for the integration of single-cell (sc) RNA-seq datasets that share only a subset of cell types. We demonstrate that by (i) correcting batch effects while preserving relevant biological variability across datasets, (ii) filtering aberrant integration anchors with a quantitative distance measure and (iii) constructing optimal guide trees for integration, STACAS can accurately align scRNA-seq datasets composed of only partially overlapping cell populations.

Availability and implementation

Source code and R package available at https://github.com/carmonalab/STACAS; Docker image available at https://hub.docker.com/repository/docker/mandrea1/stacas_demo.
Removal of peri-ovarian adipose tissue affects follicular development and lipid metabolism†
Authors: Zhu Menliang , Shen Qiyang , Li Xiaolian , Kang Jihong
Published: August 2020

The development and maturity of follicles are regulated by sex hormones and growth factors. It has been proven that peri-ovarian adipose tissue (POAT) plays an important role in folliculogenesis and fertility in the female ICR and KM mice. The aim of the present study was to further investigate whether the removal of bilateral POAT affected follicular development and lipid metabolism in the female C57BL/6 J mice. Female C57BL/6 J mice at 6-week old were sham-operated (Sham) or removed bilateral POAT (Surgery). After 2 weeks, the mice were subjected to the body composition analysis and indirect calorimetry measurement. Our results show that the Surgery mice exhibited abnormal follicular development, including increased follicular dysplasia and atresia, decreased serum sex hormone levels, and abnormal expression of follicular development-related genes. Correspondingly, the endometrial thickness of the Surgery mice was less than the Sham mice. In addition, the Surgery mice had abnormal lipid metabolism, including reduced fat mass, increased energy expenditure, and up-regulated gene and protein expression involved in lipolysis. These data confirmed the importance of POAT in the follicular development in the female reproduction and suggested the contribution of POAT to the whole-body lipid metabolism.
Tax Reform, Trade Openness and Export Product Diversification in Developing Countries
Authors: Gnangnon Sèna Kimm
Published: August 2020

This article considers the effect of tax reform on export product diversification in developing countries, including through the trade openness channel. Tax reform involves the convergence of a developing country's tax structure towards the tax structure of developed countries. The analysis uses a sample of 112 developing countries over the period 1980–2014 and shows that tax reform exerts a positive effect on export product diversification, with least developed countries enjoying a higher positive effect than other countries in the full sample. Furthermore, the higher the degree of trade openness, the greater is the magnitude of the positive effect of tax reform on export product diversification. These outcomes have important policy implications. (JEL codes: H20, O11, O14).
Structural Injustice and the Human Rights of Workers
Authors: Mantouvalou Virginia
Published: August 2020

An increasing number of jobs are precarious, making workers vulnerable to various forms of ill-treatment and exploitation. The UK Government’s main approach has been to criminalise the actions of unscrupulous employers who seek to exploit these. This approach, however, has been ineffective, partly because it ignores the broader socio-economic structures that place workers in conditions of vulnerability. This article develops an alternative solution, seeking to identify structures that force and trap workers in conditions of exploitation. It focuses specifically on what I call ‘state-mediated structural injustice', where legislative schemes that promote otherwise legitimate aims create vulnerabilities that force and trap workers in conditions of exploitation. I use examples such as restrictive visa regimes, prison work and work in immigration detention, welfare conditionality programmes, and zero-hour contracts to illustrate the unjust structures. I finally assess whether these legal structures are compatible with human rights, such as the right to private life, the prohibition of slavery, servitude, forced and compulsory labour, and the right to fair and just working conditions.
The Poetics of Comedy in Jacques Peletier Du Mans’s Art poëtique (1555)
Authors: Rayfield Lucy
Published: August 2020

This article looks at Jacques Peletier du Mans’s (1555) rhetorical and poetic treatise, Art poëtique, with a focus on his theory on comedy. It draws comparisons with Peletier’s 1541 literary treatise, which was the first translation into French of Horace’s Ars Poetica. In his 1555 treatise, Peletier developed Horace’s position on comedy into his own original theory, moulding the classical model to fit within a contemporary context and setting out the ways in which comedy most benefits early modern writers and readers. To create his theory on comedy — which was widely read in France throughout the sixteenth century — Peletier also took inspiration from other classical writers and from Italian theoreticians. Ultimately, this article helps to determine the rhetorical and theoretical position of comedy in France in the mid-sixteenth century, in relation to its classical and Italian counterparts. It also deepens and broadens our understanding of Peletier’s literary theory. Despite being one of the most prominent French literary treatises of the period, Peletier’s approach to comedy has been overlooked in scholarship, and many of his models have not been identified.
Autonomic innervation of the carotid body as a determinant of its sensitivity: implications for cardiovascular physiology and pathology
Authors: Brognara Fernanda , Felippe Igor S A , Salgado Helio C , Paton Julian F R
Published: August 2020

The motivation for this review comes from the emerging complexity of the autonomic innervation of the carotid body (CB) and its putative role in regulating chemoreceptor sensitivity. With the carotid bodies as a potential therapeutic target for numerous cardiorespiratory and metabolic diseases, an understanding of the neural control of its circulation is most relevant. Since nerve fibres track blood vessels and receive autonomic innervation, we initiate our review by describing the origins of arterial feed to the CB and its unique vascular architecture and blood flow. Arterial feed(s) vary amongst species and, unequivocally, the arterial blood supply is relatively high to this organ. The vasculature appears to form separate circuits inside the CB with one having arterial venous anastomoses. Both sympathetic and parasympathetic nerves are present with postganglionic neurons located within the CB or close to it in the form of paraganglia. Their role in arterial vascular resistance control is described as is how CB blood flow relates to carotid sinus afferent activity. We discuss non-vascular targets of autonomic nerves, their possible role in controlling glomus cell activity, and how certain transmitters may relate to function. We propose that the autonomic nerves sub-serving the CB provide a rapid mechanism to tune the gain of peripheral chemoreflex sensitivity based on alterations in blood flow and oxygen delivery, and might provide future therapeutic targets. However, there remain a number of unknowns regarding these mechanisms that require further research that is discussed.
High spatial endothelial shear stress gradient independently predicts site of acute coronary plaque rupture and erosion
Authors: Thondapu Vikas , Mamon Chris , Poon Eric K W , Kurihara Osamu , Kim Hyung Oh , Russo Michele , Araki Makoto , Shinohara Hiroki , Yamamoto Erika , Dijkstra Jouke , Tacey Mark , Lee Hang , Ooi Andrew , Barlis Peter , Jang Ik-Kyung
Published: August 2020

Aims

To investigate local haemodynamics in the setting of acute coronary plaque rupture and erosion.

Methods and results

Intracoronary optical coherence tomography performed in 37 patients with acute coronary syndromes caused by plaque rupture (n = 19) or plaque erosion (n = 18) was used for three-dimensional reconstruction and computational fluid dynamics simulation. Endothelial shear stress (ESS), spatial ESS gradient (ESSG), and oscillatory shear index (OSI) were compared between plaque rupture and erosion through mixed-effects logistic regression. Lipid, calcium, macrophages, layered plaque, and cholesterol crystals were also analysed. By multivariable analysis, only high ESSG [odds ratio (OR) 5.29, 95% confidence interval (CI) 2.57–10.89, P < 0.001], lipid (OR 12.98, 95% CI 6.57–25.67, P < 0.001), and layered plaque (OR 3.17, 95% CI 1.82–5.50, P < 0.001) were independently associated with plaque rupture. High ESSG (OR 13.28, 95% CI 6.88–25.64, P < 0.001), ESS (OR 2.70, 95% CI 1.34–5.42, P = 0.005), and OSI (OR 2.18, 95% CI 1.33–3.54, P = 0.002) independently associated with plaque erosion. ESSG was higher at rupture sites than erosion sites [median (interquartile range): 5.78 (2.47–21.15) vs. 2.62 (1.44–6.18) Pa/mm, P = 0.009], OSI was higher at erosion sites than rupture sites [1.04 × 10−2 (2.3 × 10−3–4.74 × 10−2) vs. 1.29 × 10−3 (9.39 × 10−5–3.0 × 10−2), P < 0.001], but ESS was similar (P = 0.29).

Conclusions

High ESSG is independently associated with plaque rupture while high ESSG, ESS, and OSI associate with plaque erosion. While ESSG is higher at rupture sites than erosion sites, OSI is higher at erosion sites and ESS was similar. These results suggest that ESSG and OSI may play critical roles in acute plaque rupture and erosion, respectively.
Correlates of the use of electronic devices to vape cannabis in a cohort of young Swiss male reporting current cannabis use
Authors: Fuster Daniel , Studer Joseph , Gmel Gerhard , Bertholet Nicolas
Published: August 2020

Background

Information about correlates of cannabis vaping in Europe is scarce.

Methods

In a cohort of 1613 Swiss young males currently using cannabis, we used logistic regression, adjusting for age, linguistic region and education to assess the association between sensation seeking, substance use and sociodemographic variables with cannabis vaping.

Results

Mean age was 25.38 years, 60.4% had post-secondary education and 57.3% lived in French-speaking cantons; 26.3% met criteria for nicotine dependence, 16.0% met criteria for alcohol use disorder and 34.9% used illicit drugs other than cannabis; 27.4% used cannabis at least twice a week and 27.8% met criteria for cannabis use disorder (CUD). Ninety-four participants (5.8%) reported cannabis vaping (of them 87.4% reported infrequent cannabis vaping). In the adjusted analysis, using joints with no tobacco {adjusted odds ratio (aOR) [95% confidence interval (CI)] = 1.45 (1.02–1.76)}, water pipe with [aOR (95% CI) = 1.70 (1.29–2.24)] and without tobacco [aOR (95% CI) = 2.15 (1.60–2.87)], cannabis mixed with food [aOR (95% CI) = 1.61 (1.29–2.02)], using cannabis >2 times a week [aOR (95% CI) = 3.73 (2.40–5.81)], meeting criteria for CUD [aOR (95% CI) = 4.19 (2.70–6.50)], using illicit drugs other than cannabis [aOR (95% CI) = 1.88 (1.23–2.87)], weekly number of alcohol drinks [aOR (95% CI) = 1.01 (1.00–1.03)] and living in the German-speaking area of Switzerland [aOR (95% CI) = 2.70 (1.71–4.25)] were associated with higher odds of cannabis vaping; post-secondary schooling [aOR (95% CI) = 0.37 (0.16–0.86)] and vocational training [aOR (95% CI) = 0.41 (0.17–0.99)] (as opposed to primary schooling) were associated with lower odds of cannabis vaping.

Conclusion

Cannabis vaping might be a marker of riskier behaviours among cannabis users.
When Culture Influences Genes: Positive Age Beliefs Amplify the Cognitive-Aging Benefit of APOE ε2
Authors: Levy Becca R , Slade Martin D , Pietrzak Robert H , Ferrucci Luigi
Published: August 2020

Objectives

Most studies of aging cognition have focused on risk factors for worse performance and on either genetic or environmental factors. In contrast, we examined whether 2 factors known to individually benefit aging cognition may interact to produce better cognition: environment-based positive age beliefs and the APOE ε2 gene.

Method

The sample consisted of 3,895 Health and Retirement Study participants who were 60 years or older at baseline and completed as many as 5 assessments of cognition over 8 years.

Results

As predicted, positive age beliefs amplified the cognitive benefit of APOE ε2. In contrast, negative age beliefs suppressed the cognitive benefit of APOE ε2. We also found that positive age beliefs contributed nearly 15 times more than APOE ε2 to better cognition.

Discussion

This study provides the first known evidence that self-perceptions can influence the impact of a gene on cognition. The results underscore the importance of combined psychosocial and biological approaches to understanding cognitive function in older adults.