bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of Divergent Intermediates and Convergent Synthesis of Phytofluene
Authors: Boo Chanyoung , Kim Hyein , Koo Sangho , Yang Huijeong , Han Seunghyo , Yeo Huisu , Seo Chibeom 
Published: March 2023

AbstractPractical synthetic methods for biogenetically and pharmaceutically important phytofluene were developed through the divergent preparation of key C20 substrates from a common intermediate and convergent synthesis by Wittig and Julia–Kocienski olefinations. Expeditious synthesis of phytofluene was also proposed based on the Julia sulfone-mediated chain-extension and double elimination method. Stereochemical outcomes of these olefination methods for phytofluene were compared and the Julia–Kocienski method was the mildest and most efficient reaction condition to produce all-(E)-phytofluene. Complete 1H and 13C NMR analysis of all-(E)-phytofluene is reported for the first time. Phytofluene undergoes facile thermal isomerization to other Z-isomers above room temperature, which was also confirmed with a C30 phytofluene homologue.
Research Progress on the Mechanism of the Effective Components of Duzhong (Eucommiae Cortex) on Lumbar Disk Herniation
Authors: Yang Bowen , Zhang Yanjun , Qi Hongxia , Zhang Yang 
Published: March 2023

AbstractDuzhong (Eucommiae Cortex) is one of the most commonly used Chinese herb in the treatment of lumbar disk herniation (LDH). Both the single use of it and as a Chinese herbal compound have significant clinical efficacy. Its effective components including lignans, flavonoids, iridoid terpenes, polysaccharides, etc., participate in the treatment of LDH through multiple channels, which can effectively inhibit immune and inflammatory reactions, promote the repair of intervertebral disk bone tissues, protect neurological functions, enhance cell metabolism, regulate endocrine, etc. The signal pathways of Wnt/β-catenin, TNF, HL-1, MAPK, PI3K/AKT, and NF-κB may be also involved. The action mechanism of Duzhong (Eucommiae Cortex) on LDH is characterized by multiple paths, multiple targets, and multiple component cross-actions, but the direct effects of specific components of Duzhong (Eucommiae Cortex) on LDH pathological tissues have not been clarified in the existing studies. At present, the study on the efficacy of Chinese herbs has not yet included the chemical reactions among the pharmaceutical components and pharmaceutical processing, etc. Relevant experimental studies need to further extract the effective components through purification technology, analyze the target information between Duzhong (Eucommiae Cortex) and LDH through network pharmacology and biology, and strengthen the influence of different processing methods on the pharmaceutical effects of Chinese herbs to increase the choice of clinical medication. In the experimental study, the animal cell models were finely constructed, and the pathological targets of LDH were excavated, which was conducive to the development and application of new drugs.
Relaxation time scales of interfacial water upon fluid to ripple to gel phase transitions of bilayers
Authors: Malik Sheeba , Karmakar Smarajit , Debnath Ananya 
Published: March 2023

The slow relaxation of interface water (IW) across three primary phases of membranes is relevant to understand the influence of IW on membrane functions at supercooled conditions. To this objective, a total of ∼16.26μs all-atom molecular dynamics simulations of 1,2-dimyristoyl-sn-glycerol-3-phosphocholine lipid membranes are carried out. A supercooling-driven drastic slow-down in heterogeneity time scales of the IW is found at the fluid to the ripple to the gel phase transitions of the membranes. At both fluid-to-ripple-to-gel phase transitions, the IW undergoes two dynamic crossovers in Arrhenius behavior with the highest activation energy at the gel phase due to the highest number of hydrogen bonds. Interestingly, the Stokes–Einstein (SE) relation is conserved for the IW near all three phases of the membranes for the time scales derived from the diffusion exponents and the non-Gaussian parameters. However, the SE relation breaks for the time scale obtained from the self-intermediate scattering functions. The behavioral difference in different time scales is universal and found to be an intrinsic property of glass. The first dynamical transition in the α relaxation time of the IW is associated with an increase in the Gibbs energy of activation of hydrogen bond breaking with locally distorted tetrahedral structures, unlike the bulk water. Thus, our analyses unveil the nature of the relaxation time scales of the IW across membrane phase transitions in comparison with the bulk water. The results will be useful to understand the activities and survival of complex biomembranes under supercooled conditions in the future.
Slow spectral diffusion of the NO stretching mode of [RuCl5(NO)]2− in D2O studied by 2D-IR spectroscopy and molecular dynamics simulations
Authors: Fujii Yuki , Aikawa Kyoko , Tayama Jumpei , Banno Motohiro , Ohta Kaoru , Tominaga Keisuke 
Published: March 2023

The vibrational dynamics of the NO stretching mode of [RuCl5(NO)]2− in D2O were investigated by nonlinear infrared (IR) spectroscopy. We performed IR pump–probe measurements to obtain the vibrational lifetime of this molecule. The lifetime is 31 ps, which is sufficiently long enough to study the vibrational frequency fluctuation on a slower time scale with high precision. By two-dimensional IR spectroscopy, the frequency–frequency time correlation function (FFTCF) of the NO stretching mode was characterized with a delta function plus a double-exponential function. The time constant of the slower component was ∼10 ps. We also found that the time constant does not strongly depend on temperature. In order to investigate the microscopic origin of this component, we performed classical molecular dynamics simulations. It was found that the hydration structure around the NO group was influenced by the negatively charged Cl ligands. To calculate the FFTCF decay, we employed an approximate theoretical model based on the vibrational solvatochromism theory. It was demonstrated that water fluctuations around the Cl ligands projected on the NO group correspond to the 10 ps decay component in the FFTCF. The fluctuation is related to the orientational dynamics of the water molecules attracted by the Cl ligands. By comparing the FFTCF parameters of the present solute with those of previously reported metal complexes and SCN− in D2O, we conclude that the presence of different electrostatic environments around the vibrational probe and the other interaction sites of the solute is important for understanding the slow decay component in the FFTCFs.
A probabilistic framework for uncertainty quantification in positron emission particle tracking
Authors: Offner Avshalom , Manger Sam , Vanneste Jacques 
Published: March 2023

Abstract
Positron emission particle tracking (PEPT) is an imaging method for the visualization of fluid motion, capable of reconstructing three-dimensional trajectories of small tracer particles suspended in nearly any medium, including fluids that are opaque or contained within opaque vessels. The particles are labeled radioactively, and their positions are reconstructed from the detection of pairs of back-to-back photons emitted by positron annihilation. Current reconstruction algorithms are heuristic and typically based on minimizing the distance between the particles and the so-called lines of response (LoRs) joining the detection points, while accounting for spurious LoRs generated by scattering. Here we develop a probabilistic framework for the Bayesian inference and uncertainty quantification of particle positions from PEPT data. We formulate a likelihood by describing the emission of photons and their noisy detection as a Poisson process in the space of LoRs. We derive formulas for the corresponding Poisson rate in the case of cylindrical detectors, accounting for both undetected and scattered photons. We illustrate the formulation by quantifying the uncertainty in the reconstruction of the position of a single particle on a circular path from data generated by state-of-the-art Monte Carlo simulations. The results show how the observation time

Δ
t

can be chosen optimally to balance the need for a large number of LoRs with the requirement of small particle displacement imposed by the assumption that the particle is static over

Δ
t

. We further show how this assumption can be relaxed by inferring jointly the position and velocity of the particle, with clear benefits for the accuracy of the reconstruction.
Stability of the

2p2 3Pe

state of two-electron atoms near to critical nuclear charge
Authors: Zheng Ruo Yu , Jiao Li Guang , Liu Aihua , Ma Jia , Montgomery Jr Henry E , Ho Yew Kam , Fritzsche Stephan 
Published: March 2023

Abstract
Critical stability of the metastable bound

2

p

2

3

P

e

state of two-electron atoms near the critical nuclear charge Z

c
(smaller than which the bound state ceases to exist) is investigated by employing the explicitly correlated Hylleraas-configuration interaction basis function. Our numerical calculation shows that, when the nuclear charge decreases to Z

c
, the ionization energy of the system approaches zero linearly and this behavior is fully consistent with the Hellmann–Feynman theorem. Radial and angular physical quantities as well as the inner and outer electron radial density distributions are calculated to reveal the classical geometric structure of the two-electron atom. The inner electron can be well modeled by a hydrogenic model in the 2 p state and its density distribution does not change much as the nuclear charge is changed. The outer electron, which is still localized in a finite region near the nucleus before the system transforms into a well-defined resonance, is shifted notably into a far-distance region. The critical stability of the system near the bound-continuum limit is therefore dominated by the outer electron.
Orbital magnetization of three-dimensional Dirac electrons in the quantum limit
Authors: Kawamura Shogo , Fuseya Yuki 
Published: March 2023

Abstract
In this study, we evaluated the dependence of magnetization of three-dimensional Dirac electrons in the quantum limit on the magnetic field and temperature. The magnetization was calculated by differentiating the free energy with respect to the magnetic field. The field and temperature dependence of the chemical potential were entirely considered under the canonical ensemble condition. The total magnetization M consisted of two contributions from the conduction

M

c

and valence

M

v

bands.

M

v

was insensitive to temperature and exhibited sub-linear field dependence, which is consistent with the previous research on Dirac electrons. By contrast,

M

c

was sensitive to both temperature and magnetic field, yielding a non-trivial contribution to the total M. As a result, the properties of total M changed at approximately

k

B

T
≃

E

F

, where

E

F

is the Fermi energy measured from the band bottom and

k

B

is the Boltzmann constant. At low temperatures

k
B

T
≲

E
F

, M exhibited sub-linear field dependence, whereas M exhibited super-linear field dependence at high temperatures

k

B

T
≳

E

F

. This qualitative change in the field dependence of M will play a significant role in the magnetization of Dirac electrons with small

E

F

.
First of its kind: a test artifact for direct laser writing
Authors: Fritzsche Sven , Pauw Brian R , Weimann Christiane , Sturm Heinz 
Published: March 2023

Abstract
With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate (1) the high geometrical resolution of fs-LDW structures and (2) the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement.
Students’ understanding of electrostatic force as a vector quantity at the undergraduate level
Authors: Chhabra Mahima , Das Ritwick 
Published: March 2023

Abstract
Electrostatic force is the preliminary and fundamental topic that forms the bedrock on which the conceptual framework of electromagnetism is built. Being a ‘vector’ quantity, electromagnetic force naturally inherits direction as well as magnitude. The conceptualization of such physical quantities may pose a challenge. The present work explores how students conceptualize the construct of electrostatic force from the viewpoint of its vector nature. Our effort is directed towards engaging students in problems aimed at their understanding of the concept of electrostatic force (a physical quantity) and analyse their responses for identifying the conceptual challenges. Our observations reveal that a significant fraction of conceptual difficulties in the concept of electrostatic force are due to insufficient understanding of operations involving vector quantities. The implications of this work indicate that the pedagogical aspects in physics classroom and curriculum design needs to be researched holistically so as to bridge-in the gaps obstructing the desired cognitive framework of students.
A treatment plan optimization method with direct minimization of number of energy jumps for proton arc therapy
Authors: Zhang Gezhi , Long Yong , Lin Yuting , Chen Ronald C , Gao Hao 
Published: March 2023

Abstract

Objective. The optimization of energy layer distributions is crucial to proton arc therapy: on one hand, a sufficient number of energy layers is needed to ensure the plan quality; on the other hand, an excess number of energy jumps (NEJ) can substantially slow down the treatment delivery. This work will develop a new treatment plan optimization method with direct minimization of (NEJ), which will be shown to outperform state-of-the-art methods in both plan quality and delivery efficiency. Approach. The proposed method jointly optimizes the plan quality and minimizes the NEJ. To minimize NEJ, (1) the proton spots x is summed per energy layer to form the energy vector y; (2) y is binarized via sigmoid transform into y

1
; (3) y
1 is multiplied with a predefined energy order vector via dot product into y
2; (4) y
2 is filtered through the finite-differencing kernel into y
3 in order to identify NEJ; (5) only the NEJ of y
3 is penalized, while x is optimized for plan quality. The solution algorithm to this new method is based on iterative convex relaxation. Main results. The new method is validated in comparison with state-of-the-art methods called energy sequencing (ES) method and energy matrix (EM) method. In terms of delivery efficiency, the new method had fewer NEJ, less energy switching time, and generally less total delivery time. In terms of plan quality, the new method had smaller optimization objective values, lower normal tissue dose, and generally better target coverage. Significance. We have developed a new treatment plan optimization method with direct minimization of NEJ, and demonstrated that this new method outperformed state-of-the-art methods (ES and EM) in both plan quality and delivery efficiency.
Electron dynamics in planar radio frequency magnetron plasmas: II. Heating and energization mechanisms studied via a 2d3v particle-in-cell/Monte Carlo code
Authors: Eremin D , Berger B , Engel D , Kallähn J , Köhn K , Krüger D , Xu L , Oberberg M , Wölfel C , Lunze J , Awakowicz P , Schulze J , Brinkmann R P 
Published: March 2023

Abstract
The present work investigates electron transport and heating mechanisms using an (r, z) particle-in-cell simulation of a typical rf-driven axisymmetric magnetron discharge with a conducting target. Due to a strong geometric asymmetry and a blocking capacitor, the discharge features a large negative self-bias conducive to sputtering applications. Employing decomposition of the electron transport parallel and perpendicular to the magnetic field lines, it is shown that for the considered magnetic field topology the electron current flows through different channels in the (r, z) plane: a ‘transverse’ one, which involves current flow through the electrons’ magnetic confinement region (EMCR) above the racetrack, and two ‘longitudinal’ ones, where electrons’ guiding centers move along the magnetic field lines. Electrons gain energy from the electric field along these channels following various mechanisms, which are rather distinct from those sustaining dc-powered magnetrons. The longitudinal power absorption involves mirror-effect heating (MEH), nonlinear electron resonance heating, magnetized bounce heating (MBH), and the heating by the ambipolar field at the sheath-presheath interface. The MEH and MBH represent two new mechanisms missing from the previous literature. The MEH is caused by a reversed electric field needed to overcome the mirror force generated in a nonuniform magnetic field to ensure sufficient flux of electrons to the powered electrode, and the MBH is related to a possibility for an electron to undergo multiple reflections from the expanding sheath in the longitudinal channels connected by the arc-like magnetic field. The electron heating in the transverse channel is caused mostly by the essentially collisionless Hall heating in the EMCR above the racetrack, generating a strong

E

×

B

azimuthal drift velocity. The latter mechanism results in an efficient electron energization, i.e. energy transfer from the electric field to electrons in the inelastic range. Since the main electron population energized by this mechanism remains confined within the discharge for a long time, its contribution to the ionization processes is dominant.
Electron dynamics in planar radio frequency magnetron plasmas: I. The mechanism of Hall heating and the µ-mode
Authors: Eremin Denis , Engel Dennis , Krüger Dennis , Wilczek Sebastian , Berger Birk , Oberberg Moritz , Wölfel Christian , Smolyakov Andrei , Lunze Jan , Awakowicz Peter , Schulze Julian , Brinkmann Ralf Peter 
Published: March 2023

Abstract
The electron dynamics and the mechanisms of power absorption in radio-frequency (RF) driven, magnetically enhanced capacitively coupled plasmas at low pressure are investigated. The device in focus is a geometrically asymmetric cylindrical magnetron with a radially nonuniform magnetic field in axial direction and an electric field in radial direction. The dynamics is studied analytically using the cold plasma model and a single-particle formalism, and numerically with the inhouse energy and charge conserving particle-in-cell/Monte Carlo collisions code ECCOPIC1S-M. It is found that the dynamics differs significantly from that of an unmagnetized reference discharge. In the magnetized region in front of the powered electrode, an enhanced electric field arises during sheath expansion and a reversed electric field during sheath collapse. Both fields are needed to ensure discharge sustaining electron transport against the confining effect of the magnetic field. The corresponding azimuthal

E

×

B

-drift can accelerate electrons into the inelastic energy range which gives rise to a new mechanism of RF power dissipation. It is related to the Hall current and is different in nature from Ohmic heating, as which it has been classified in previous literature. The new heating is expected to be dominant in many magnetized capacitively coupled discharges. It is proposed to term it the ‘µ-mode’ to separate it from other heating modes.
Mechanisms leading to plasma activated water high in nitrogen oxides
Authors: Matějka F , Galář P , Khun J , Scholtz V , Kůsová K 
Published: March 2023

Abstract
Plasma activated water (PAW) is a unique highly reactive medium, traditionally used in medicine and agriculture because of its decontamination and disinfection abilities. Recently, we have shown that this medium can also be beneficial for tailoring the surface chemistry of semiconductor nanostructures if its composition is tuned to contain a high concentration of nitrogen-related species (HiN:PAW). However, pathways leading to the production of HiN:PAW remained unclear, which we address in this article. By monitoring the composition of the produced PAW and the concentration of selected species in the discharge under different activation geometries and discharge conditions, we identify the activation geometries favourable for the production of HiN:PAW using two phenomenological factors, a barrier parameter P and a maximum effective radius of the vessel r
max. A key point is the presence of a barrier area in the discharge reactor, which forms as a result of the favourable activation geometry and a discharge with prevailing more reactive atomic species. This area acts as a partial barrier between the discharge and the surrounding air atmosphere, limiting, but still allowing a flow of source N2 molecules from the surrounding atmosphere. The minimal and ideal build-up times of 10 and 30 min, respectively, for the discharge to stabilize are also reported. Using the reported experimental settings, we were able to produce HiN:PAW containing a mixture of various reactive species beneficial for the surface modification of nanoparticles, with the NO3
− to H2O2 ratio of at least 20 × 103: 1, in contrast to approximately 1:1 under more traditional conditions.
On projection method for numerical solution of hypersingular integral equations of the first kind combined with quadrature methods
Authors: Elahi M R , Mahmoudi Y , Salimi Shamloo A , Jahangiri Rad M 
Published: March 2023

Abstract
The Fredholm integral equations of the first kind with two regular and hypersingular kernels are considered on [−1, 1]. The hypersingular kernel is considered smooth enough with no additional conditions. A projection method based on second kind Chebyshev polynomials approximation, combined with quadrature integration method, is developed to obtain high accurate approximations. The proposed method reduces the underlying integral equation to a system of algebraic equations. Several illustrative examples are provided to show the efficiency of the method.