bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum entanglement and quantum teleportation
Authors: Shih Y.H.
Published: May 2022

One of the most surprising consequences of quantum mechanics is the entanglement of two or more distance particles. The “ghost” interference and the “ghost” image experiments demonstrated the astonishing nonlocal behavior of an entangled photon pair. Even though we still have questions in regard to fundamental issues of the entangled quantum systems, quantum entanglement has started to play important roles in quantum information and quantum computation. Quantum teleportation is one of the hot topics. We have demonstrated a quantum teleportation experiment recently. The experimental results proved the working principle of irreversibly teleporting an unknown arbitrary quantum state from one system to another distant system by disassembling into and then later reconstructing from purely classical information and nonclassical EPR correlations. The distinct feature of this experiment is that the complete set of Bell states can be distinguished in the Bell state measurement. Teleportation of a quantum state can thus occur with certainty in principle.
Quantum thermodynamics
Authors: Hoffmann K.H.
Published: May 2022

Quantum theory and thermodynamics are two important corner stones in our understanding of nature. In this paper we discuss a number of interesting topics where both fields interact starting from Max Planck's introduction of the energy quantum to todays open questions about the validity of the second law in the quantum regime.
The emergence of Quantum Schools: Munich, Göttingen and Copenhagen as new centers of atomic theory
Authors: Eckert M.
Published: May 2022

The institutes of Arnold Sommerfeld in Munich, Niels Bohr in Copenhagen, and Max Born in Göttingen became the leading centers for the study of quantum theory in the first decades of the twentieth century. Although founded for a broader range of theoretical physics, the quantum became the major topic of research in Munich after the Bohr‐Sommerfeld‐model of the atom (1913–16). The heyday came in the 1920s, when Bohr's and Born's institutes started operation and became further attractive centers for ambitious theorists all over the world. The discovery of quantum mechanics (1925) should be regarded not only as the achievement of a few young geniuses (in particular Werner Heisenberg and Wolfgang Pauli) but also as the result of a collaborative effort emerging in the new social and intellectual environment of their teachers' schools in Munich, Göttingen and Copenhagen.
Molecular beams entwined with quantum theory: A bouquet for Max Planck
Authors: Herschbach D.
Published: May 2022

In an era when the fledgling quantum theory was “uncertain and even gave contradictory answers,” Otto Stern undertook to employ molecular beams to test directly fundamental aspects of the theory. During 1921‐1935, this led to five decisive experiments reviewed here, resulting in the discovery or demonstration of space quantization, de Broglie matter waves, anomalous magnetic moments of the proton and neutron, recoil of an atom on emission of a photon, and the limitation of scattering cross‐sections for molecular collisions imposed by the uncertainty principle.
Superconductivity in ultrasmall metallic grains
Authors: von Delft Jan
Published: May 2022

We review recent experimental and theoretical work on superconductivity in ultrasmall metallic grains, i.e. grains sufficiently small that the conduction electron energy spectrum becomes discrete. The discrete excitation spectrum of an individual grain can be measured by the technique of single‐electron tunneling spectroscopy, and reveals parity effects indicative of pairing correlations in the grain. After introducing the discrete BCS model that has been used to model such grains, we review a phenomenological, grand‐canonical, variational BCS theory describing the paramagnetic breakdown of these pairing correlations with increasing magnetic field. We also review recent canonical theories that have been developed to describe how pairing correlations change during the crossover, with decreasing grain size, from the bulk limit to the limit of few electrons, and compare their results to those obtained using Richardson's exact solution of the discrete BCS model.
Energy momentum tensor in local causal perturbation theory
Authors: Prange Dirk
Published: May 2022

We study the energy momentum tensor in the Bogoliubov‐Epstein‐Glaser approach to perturbation theory. It is found to be locally conserved for a class of theories containing no derivated fields in the interaction. For the massless φ4 ‐theory we derive the trace anomaly of the improved tensor.
On the prolongation structure of the Landau‐Lifshitz equation for an anisotropic ferromagnet
Authors: Hoenselaers C.
Published: May 2022

We study the prolongation algebra for the Landau‐Lifshitz equation. We shall recover the known linear problems for this model. Moreover, we shall also display a 6‐dimensional linear linear problem which is linear in the spectral parameter λ.
Geometric classification of the torsion tensor of space‐time
Authors: Capozziello S. , Lambiase G. , StornaioloI C.
Published: May 2022

Torsion appears in literature in quite different forms. Generally, spin is considered to be the source of torsion, but there are several other possibilities in which torsion emerges in different contexts. In some cases a phenomenological counterpart is absent, in some other cases torsion arises from sources without spin as a gradient of a scalar field. Accordingly, we propose two classification schemes. The firstone is based on the possibility to construct torsion tensors from the product of a covariant bivector and a vector and their respective space‐time properties. The secondone is obtained by starting from the decomposition of torsion into three irreducible pieces. Their space‐time properties again lead to a complete classification. The classifications found are given in a U 4, a four dimensional space‐time where the torsion tensors have some peculiar properties. The irreducible decomposition is useful since most of the phenomenological work done for torsion concerns four dimensional cosmological models. In the second part of the paper two applications of these classification schemes are given. The modifications of energy‐momentum tensors are considered that arise due to different sources of torsion. Furthermore, we analyze the contributions of torsion to shear, vorticity, expansion and acceleration. Finally the generalized Raychaudhuri equation is discussed.
Exact solutions for extended waves in 1d anharmonic lattices
Authors: Fischer Fred
Published: May 2022

A cyclic chain of n equal classic particles coupled by anharmonic forces has a set of extended vibrational modes, for which exact solutions are given. This requires for the power law of the forces certain conditions to be fulfilled. Each mode is characterized by a wave number and the undulations of the particles depend on the total energy and on a new constant of motion that formally expresses a kind of angular momentum. Exact solutions for n = 7 with a twelfth power potential are discussed.
Noether Charges for self‐interacting quantum field theories in curved spacetimes with a Killing‐vector
Authors: Hollands Stefan
Published: May 2022

We consider a self‐interacting, perturbative Klein‐Gordon quantum field in a curved spacetime admitting a Killing vector field. We show that the action of this spacetime symmetry on interacting field operators can be implemented by a Noether charge which arises, in a certain sense, as a surface integral over the time‐component of some interacting Noether current‐density associated with the Killing field. The proof of this involves the demonstration of a corresponding set of Ward identities. Our work is based on the perturbative construction by Brunetti and Fredenhagen (Commun. Math. Phys. 208 (2000) 623—661) of self‐interacting quantum field theories in general globally hyperbolic spacetimes.
A derivation of Weyl gravity
Authors: Boulanger Nicolas , Henneaux Marc
Published: May 2022

In this paper, two things are done. (i) Using cohomological techniques, we explore the consistent deformations of linearized conformal gravity in 4 dimensions. We show that the only possibility involving no more than 4 derivatives of the metric (i.e., terms of the form ∂4gμν, ∂3gμν ∂gαβ, ∂2gμν ∂2gαβ, ∂2gμν ∂gαβ ∂gρσ or ∂gμν ∂gαβ ∂gρσ ∂gγδ with coefficients that involve undifferentiated metric components — or terms with less derivatives) is given by the Weyl action S ∼ ∫ d4x Wαβγδ Wαβγδ, in much the same way as the Einstein‐Hilbert action describes the only consistent manner to make a Pauli‐Fierz massless spin‐2 field self‐interact with no more than 2 derivatives. No a priori requirement of invariance under diffeomorphisms is imposed: this follows automatically from consistency. (ii) We then turn to “multi‐Weyl graviton” theories. We show the impossibility to introduce cross‐interactions between the different types of Weyl gravitons if one requests that the action reduces, in the free limit, to a sum of linearized Weyl actions. However, if different free limits are authorized, cross‐couplings become possible. An explicit example is given. We discuss also how the results extend to other spacetime dimensions.
Thermodynamics of a 4‐site Hubbard model by analytical diagonalization
Authors: Schumann R.
Published: May 2022

By use of the conservation laws a four‐site Hubbard model coupled to a particle bath within an external magnetic field in z‐direction was diagonalized. The analytical dependence of both the eigenvalues and the eigenstates on the interaction strength, the chemical potential and magnetic field was calculated. It is demonstrated that the low temperature behaviour is determined by a delicate interplay between many‐particle states differing in electron number and spin if the electron density is away from half‐filling. The grand partition sum is calculated and the specific heat, the susceptibility as well as various correlation functions and spectral functions are given in dependence of the interaction strength, the electron occupation and the applied magnetic field. For both the grand canonical and the canonical ensemble the high‐temperature crossing points of the specific heat are calculated. Whereas in the weak correlation regime the universal value calculated by second order perturbation theory for several Hubbard systems being in the thermodynamic limit is confirmed, these crossing points vanish for intermediate to strong correlation.
Basics of superluminal signals
Authors: Nimtz G. , Haibel A.
Published: May 2022

The paper elucidates the physical basis of experimental results on superluminal signal velocity. It will be made plausible that superluminal signals do not violate the principle of causality but they can shorten the vacuum time span between cause and effect. The causal behaviour is based on the property that a physical signal has a finite duration as a result of its frequency band limitation.
Semi‐classical description of ionic and electronic dynamics in metal clusters
Authors: Giglio E. , Suraud E. , Reinhard P.‐G.
Published: May 2022

We present a selfconsistent semi‐classical description of metal clusters with explicit ionic background. We show in particular how the flexibility of the Husimi picture allows a proper, self contained, description of ground state as well as dynamical properties of metal clusters. This leads to a coupled electrons + ions molecular dynamics, which may be followed over long times (typically one picosecond). We consider real time dynamics for electrons at a Vlasov‐LDA level and include dynamical correlations by an Ühling‐Uhlenbeck collision term (VUU). We discuss the effect of the Husimi representation on the electronic dynamics and the impact of a constant isotropic differential cross‐section in the UU collision term, as compared to a velocity dependent anisotropic differential cross section. Finally, we show that the VUU approach is capable of curing the artificial dissipation of an initial fermionic distribution function towards a classical Boltzmann equilibrium over long times.
Quantized superfields
Authors: Constantinescu Florin , Gut Markus , Scharf Günter
Published: May 2022

We construct quantized free superfields and represent them as operator‐valued distributions in Fock space starting with the Majorana field. We then analyse the algebras generated by free component quantum fields together with the Susy generators Q, . This enables us to obtain the quantized chiral superfield by finite Susy transformation from its scalar component. To get hermitian superfields we study by the same method a second scalar field algebra from which various scalar superfields can be obtained by exponentiation. Next we investigate the vector algebra and use it to construct the massive vector superfield. Surprisingly enough, the result is totally different from the vector multiplet in the literature. It contains two hermitian four‐vector components instead of one and a spin‐3/2 field similar to the gravitino in supergravity.
Resolution of an emission electron microscope in the presence of magnetic fields on the object
Authors: Nepijko S.A. , Sedov N.N. , Schönhense G. , Muschiol U. , Schneider C.M. , Zennaro S. , Zema N.
Published: May 2022

The known Brüche‐Recknagel formula for determining the resolving power of an emission electron microscope (EEM) was derived assuming idealized conditions: the object surface was planar, and the accelerating electric field was homogeneous. However, deviations from these conditions will deteriorate the resolving power. This can be caused by a surface topography as well as local electric or magnetic fields on the object surface. In the present paper the resolving power of an EEM is calculated for the case when there are local magnetic fields on the object surface. The deterioration of the resolving power will then depend on the local field strength not only in the given point of the object surface, but also in adjacent regions. The estimations performed show that the lateral resolution in EEM under the influence of magnetic microfields of real ferromagnets can be several times worse than in the case of the absence of these fields.
Noncommutative geometry and fundamental interactions: the first ten years
Authors: Gracia‐Bondía J.M.
Published: May 2022

This is the full text of a survey talk for nonspecialists, delivered at the 66th Annual Meeting of the German Physical Society in Leipzig, March 2002. We have not taken pains to suppress the colloquial style. References are given only insofar as they help to underline the points made; this is not a full‐blooded survey. The connection between noncommutative field theory and string theory is mentioned, but deemphasized. Contributions to noncommutative geometry made in Germany are emphasized.
Coated conductors containing grains with big aspect ratios
Authors: Leitenmeier S. , Bielefeldt H. , Hammerl G. , Schmehl A. , Schneider C.W. , Mannhart J.
Published: May 2022

It is shown that the critical currents of high‐Tcsuperconducting tapes fabricated by the coated conductor technologies are enhanced considerably if grain arrangements with large effective grain boundary areas are used. Increasing the aspect ratios of the grains reduces the deleterious effects of the grain boundaries. A practical road to competitive high‐Tccables is proposed.
Linear differential equations for the one‐dimensional scattering problem
Authors: Sedrakian D.M. , Khachatrian A.Z.
Published: May 2022

The transmission and reflection amplitudes of an electron moving in a one dimensional potential of arbitrary form are obtained using the transfer matrix method. It is shown that the one‐dimensional scattering problem, in its most general form, can be reduced to Cauchy problem for a set of two linear differential equations.
Black holes: a physical route to the Kerr metric
Authors: Meinel R.
Published: May 2022

As a consequence of Birkhoff's theorem, the exterior gravitational field of a spherically symmetric star or black hole is always given by the Schwarzschild metric. In contrast, the exterior gravitational field of a rotating (axisymmetric) star differs, in general, from the Kerr metric, which describes a stationary, rotating black hole. In this paper I discuss the possibility of a quasi–stationary transition from rotating equilibrium configurations of normal matter to rotating bla ck holes.
Length measurement in accelerated systems
Authors: Mashhoon B. , Muench U.
Published: May 2022

We investigate the limitations of length measurements by accelerated observers in Minkowski spacetime brought about via the hypothesis of locality, namely, the assumption that an accelerated observer at each instant is equivalent to an otherwise identical momentarily comoving inertial observer. We find that consistency can be achieved only in a rather limited neighborhood around the observer with linear dimensions that are negligibly small compared to the characteristic acceleration length of the observer.
Linear pre‐metric electrodynamics and deduction of the light cone
Authors: Rubilar G.F.
Published: May 2022

We formulate a general framework for describing the electromagnetic properties of spacetime. These properties are encoded in the ‘constitutive tensor of the vacuum’, a quantity analogous to that used in the description of material media. We give a generally covariant derivation of the Fresnel equation describing the local properties of the propagation of electromagnetic waves for the case of the most general possible linear constitutive tensor. We also study the particular case in which a light cone structure is induced and the circumstances under which such a structure emerges. In particular, we will study the relationship between the dual operators defined by the constitutive tensor under certain conditions and the existence of a conformal metric. Closure and symmetry of the constitutive tensor will be found as conditions which ensure the existence of a conformal metric. We will also see how the metric components can be explicitly deduced from the constitutive tensor if these two conditions are met. Finally, we will apply the same method to explore the consequences of relaxing the condition of symmetry and how this affects the emergence of the light cone.
Quantum spin chains with various defects
Authors: Schuster C. , Eckern U.
Published: May 2022

Using the density matrix renormalization group (DMRG) method, we study the quantum coherence in one‐dimensional disordered spin chains and Fermi systems. We consider in detail spinless fermions on a ring, and compare the influence of several kinds of impurities in a gapless and a dimerized, gapped system. In the translation‐invariant system a so‐called site‐impurity, which can be realized by a local potential or a modification of one link, increases for repulsive interaction, and decreases for attractive interaction, upon renormalization. The weakening of two neighbouring bonds, which is a realization of a so‐called bond‐impurity, on the other hand, is healed for repulsive interaction, but enhanced for intermediate attractive interactions. This leads to a strong suppression of the quantum coherence measured by the phase sensitivity, but not to localization. Adding a local distortion to a dimerized system, we find that even the presence of a single site‐impurity increases the metallic region found in the dimerized model. For a strong dimerization and a high barrier, an additional sharp maximum, is seen in the phase sensitivity as a function of interaction, already for systems with about 100 sites. A bond‐impurity in the dimerized system also opens a small metallic window in the otherwise isolating regime.
Traversal time for Dirac particles through a potential barrier
Authors: Li C‐F. , Chen X.
Published: May 2022

A traversal time that has no problem of superluminality was advanced for particles to tunnel through potential barriers in the non‐relativistic quantum theory in a previous paper by C.‐F. Li and Q. Wang, Physica B 296 (2001) 356. This time is generalized in this paper to Dirac's relativistic quantum theory. Both evanescent and propagating cases are considered. It is shown that the traversal time in the evanescent case has much the same properties as in the non‐relativistic quantum theory and thus has no problem of superluminality. It also gets rid of the problem of superluminality in the propagating case. Comparisons with the dwell time, the group delay, and the velocity of monochromatic front are also made.
Intramolecular Energy and Solvent‐Dependent Chirality Transfer within a BINOL‐Perylene Hetero‐Cyclophane
Authors: Ouyang Guanghui , Rühe Jessica , Zhang Yang , Lin Mei‐Jin , Liu Minghua , Würthner Frank
Published: May 2022

Multichromophoric macrocycles and cyclophanes are important supramolecular architectures for the elucidation of interchromophoric interactions originating from precise spatial organization. Herein, by combining an axially chiral binaphthol bisimide (BBI) and a bay‐substituted conformationally labile twisted perylene bisimide (PBI) within a cyclophane of well‐defined geometry, we report a chiral PBI hetero‐cyclophane (BBI‐PBI) that shows intramolecular energy and solvent‐regulated chirality transfer from the BBI to the PBI subunit. Excellent spectral overlap and spatial arrangement of BBI and PBI lead to efficient excitation energy transfer and subsequent PBI emission with high quantum yield (80–98 %) in various solvents. In contrast, chirality transfer is strongly dependent on the respective solvent as revealed by circular dichroism (CD) spectroscopy. The combination of energy and chirality transfer affords a bright red circularly polarized luminescence (CPL) from the PBI chromophore by excitation of BBI.
Asymmetrically Doping a Platinum Atom into a Au38 Nanocluster for Changing the Electron Configuration and Reactivity in Electrocatalysis
Authors: Liu Xu , Wang Endong , Zhou Meng , Wan Yan , Zhang Yuankun , Liu Haoqi , Zhao Yue , Li Jin , Gao Yi , Zhu Yan
Published: May 2022

It is an obstacle to precisely manipulate a doped heteroatom into a desired position in a metal nanocluster. Herein, we overcome this difficulty to obtain Pt1Au37(SCH2PhtBu)24 and Pt2Au36(SCH2PhtBu)24 nanoclusters via controllably doping Pt atoms into the kernels of Au38(SCH2PhtBu)24. We reveal that asymmetrical doping of one Pt atom into either of the cores of Au38(SCH2PhtBu)24 elevates the relative energy of the HOMO (highest occupied molecular orbital) accompanied by one valence electron loss of Pt1Au37(SCH2PhtBu)24, compared to Au38(SCH2PhtBu)24 with 14 electrons, while symmetrical doping of two Pt atoms into the cores of Au38(SCH2PhtBu)24 narrows the HOMO–LUMO gap (LUMO: lowest unoccupied molecular orbital) of Pt2Au36(SCH2PhtBu)24 with two valence electrons less. Consequently, Pt1Au37(SCH2PhtBu)24 shows an electron‐spin‐induced high activity for CO2 electroreduction, whereas Pt2Au36(SCH2PhtBu)24 is least efficient and Au38(SCH2PhtBu)24 has a decent performance.
Highly Selective Carbonylation of CH3Cl to Acetic Acid Catalyzed by Pyridine‐Treated MOR Zeolite
Authors: Fang Xudong , Wen Fuli , Ding Xiangnong , Liu Hanbang , Chen Zhiyang , Liu Zhaopeng , Liu Hongchao , Zhu Wenliang , Liu Zhongmin
Published: May 2022

The selective conversion of methane to high value‐added chemicals under mild conditions is of great significance for the commercially viable and sustainable utilization of methane but remains a formidable challenge. Herein, we report a strategy for efficiently converting methane to acetic acid via CH3Cl as an intermediate. Up to 99.3 % acetic acid and methyl acetate (AA+MA) selectivity was achieved over pyridine‐pretreated MOR (MOR‐8) under moderate conditions of 523 K and 2.0 MPa. Water, conventionally detrimental to carbonylation reaction over zeolite catalysts, was conducive to the production of AA in the current reaction system. In the 100 h continuous test with the MOR‐8 catalyst, the average AA+MA selectivity remained over 98 %. AA was formed by carbonylation of methoxy groups within 8‐membered rings of MOR followed by hydrolysis. This strategy provided an approach for highly efficient utilization of methane to oxygenates under mild reaction conditions.
Ru–Co Pair Sites Catalyst Boosts the Energetics for the Oxygen Evolution Reaction
Authors: Zheng Xiaobo , Yang Jiarui , Xu Zhongfei , Wang Qishun , Wu Jiabin , Zhang Erhuan , Dou Shixue , Sun Wenping , Wang Dingsheng , Li Yadong
Published: May 2022

Manipulating the coordination environment of the active center via anion modulation to reveal tailored activity and selectivity has been widely achieved, especially for carbon‐based single‐atom site catalysts (SACs). However, tuning ligand fields of the active center by single‐site metal cation regulation and identifying the effects on the resulting electronic configuration is seldom explored. Herein, we propose a single‐site Ru cation coordination strategy to engineer the electronic properties by constructing a Ru/LiCoO2 SAC with atomically dispersed Ru−Co pair sites. Benefitting from the strong electronic coupling between Ru and Co sites, the catalyst possesses an enhanced electrical conductivity and achieves near‐optimal oxygen adsorption energies. Therefore, the optimized catalyst delivers superior oxygen evolution reaction (OER) activity with low overpotential, the high mass activity of 1000 A goxide−1 at a small overpotential of 335 mV, and excellent long‐term stability. It also exhibits rapid kinetics with superior rate capability and outstanding durability in a zinc–air battery.
Effects of glyphosate on the growth, development, and physiological functions of silkworm, Bombyx mori
Authors: Feng Piao , Dai Minli , Yang Jin , Wang Yuanfei , Mao Tingting , Su Wujie , Li Fanchi , Sun Haina , Wei Jing , Li Bing
Published: May 2022

Glyphosate is an herbicide widely used worldwide, but whether it is safe to nontarget organisms is controversial. In this study, the lepidopteran model insect silkworm was used to investigate the effects of glyphosate residues. The LC50 (72 h) of glyphosate on silkworm was determined to be 14875.98 mg/L, and after exposure to glyphosate at 2975.20 mg/L (a concentration comparable to that used for weed control in mulberry fields), silkworm growth was inhibited by 9.00%, total cocoon weight was lowered by 10.53%, feed digestibility was decreased by 7.56%, and the activities of alpha‐amylase and trypsin were reduced by 10.41% and 21.32%, respectively. Pathological analysis revealed that glyphosate exposure led to significantly damaged midgut, along with thinner basal layer, shedding microvilli, blurred cytoplasmic membrane, and appearance of vacuoles. Exposure to glyphosate also led to accumulation of peroxides in the intestinal tissue; the messenger RNA transcription of SOD, Cu/Zn‐SOD, and Mn‐SOD was all significantly upregulated by glyphosate treatment for 24 h, while CAT transcription was increased at 24, 48, and 72 h. The activity of SOD was increased significantly at 24 h, while significant activity changes were observed for CAT at 72 and 96 h. These results indicated that exposure to glyphosate caused oxidative stress in the midgut of silkworm and affected the midgut's physiological function. This study provides important insights in evaluating the impact of glyphosate residues in the environment on nontarget organisms.
Double Thia/sulfone[7]helicenes with Controlled Photophysical and Chiroptical Properties by Heteroatom Variation
Authors: Zhou Long , Liu Haoliang , Tan Jingyun , Liu Chao , Cao Xiao‐Yu , Narita Akimitsu , Hu Yunbin
Published: May 2022

The development of helicenes with strong chiroptical response and controlled photophysics is highly desirable but challenging. In this work, double thia/sulfone[7]helicenes were synthesized to investigate the heteroatom effect on the photophysical and chiroptical properties of double heterohelicenes through comparison with the previously reported double oxa[7]helicene. By variation of the embedded heteroatoms from oxygen to sulfur, the absorption and emission were significantly red‐shifted, along with the improved luminescence dissymmetry factor (glum). In particular, the double sulfone[7]helicene exhibited strong red to near‐infrared (NIR) emission withglumof 1.1×10−3, suggesting its potential as a NIR circularly polarized luminescence emitter.
Characterization of chromospheric activity based on Sun‐as‐a‐star spectral and disk‐resolved activity indices
Authors: Dineva Ekaterina , Pearson Jeniveve , Ilyin Ilya , Verma Meetu , Diercke Andrea , Strassmeier Klaus G. , Denker Carsten
Published: May 2022

The strong chromospheric absorption lines Ca ii H & K are tightly connected to stellar surface magnetic fields. Only for the Sun, spectral activity indices can be related to evolving magnetic features on the solar disk. The Solar Disk‐Integrated (SDI) telescope feeds the Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) of the Large Binocular Telescope (LBT) at Mt. Graham International Observatory, Arizona, U.S.A. We present high‐resolution, high‐fidelity spectra that were recorded on 184 & 82 days in 2018 & 2019 and derive the Ca ii H & K emission ratio, that is, the S‐index. In addition, we compile excess brightness and area indices based on full‐disk Ca ii K‐line‐core filtergrams of the Chromospheric Telescope (ChroTel) at Observatorio del Teide, Tenerife, Spain and full‐disk ultraviolet (UV) 1600 Å images of the Atmospheric Imaging Assembly (AIA) onboard the Solar Dynamics Observatory (SDO). Thus, Sun‐as‐a‐star spectral indices are related to their counterparts derived from resolved images of the solar chromosphere. All indices display signatures of rotational modulation, even during the very low magnetic activity in the minimum of Solar Cycle 24. Bringing together different types of activity indices has the potential to join disparate chromospheric datasets yielding a comprehensive description of chromospheric activity across many solar cycles.
Restriction of intraflagellar transport to some microtubule doublets: An opportunity for cilia diversification?
Authors: Mallet Adeline , Bastin Philippe
Published: May 2022

Cilia are unique eukaryotic organelles and exhibit remarkable conservation across evolution. Nevertheless, very different types of configurations are encountered, raising the question of their evolution. Cilia are constructed by intraflagellar transport (IFT), the movement of large protein complexes or trains that deliver cilia components to the distal tip for assembly. Recent data revealed that IFT trains are restricted to some but not all nine doublet microtubules in the protist Trypanosoma brucei. Here, we propose that restricted positioning of IFT trains could offer potent options for cilia to evolve towards more complex (addition of new structural elements like in spermatozoa) or simpler configuration (loss of some elements like in primary cilia), and therefore be a driver of cilia diversification. We present two hypotheses to explain how IFT trains could be restricted to some doublets, either by a triage process taking place at the basal body level or by the development of molecular differences between ciliary microtubules.
High‐throughput UPLC‐Q‐TOF‐MS/MS coupled with multivariable data processing approach for the rapid screening and characterization of chemical constituents and potential bioactive compounds from Danggui Shaoyao San
Authors: Li Na , Yu Yongzhou , Cui Xiaoyan , Liu Qi , Xiong Hui
Published: May 2022

Danggui Shaoyao San (DSS), a herbal formula, has been widely used for decades in China to treat senile dementia and dysmenorrhea. Here, an integrative high‐throughput UPLC‐Q‐TOF‐MS/MS method coupled with a multivariable data processing approach was established for rapidly screening and identifying chemical constituents and potential bioactive compounds from DSS. Through the comparison with mass fragment ions, relevant literature, and in‐house reference material database coupled with MS cleavage mechanism, 150 chemical constituents, mainly including triterpenoids, flavonoids, phathalides, and organic acids, were tentatively characterized. Most of them were identified for the first time. Then, principal component analysis was used to evaluate the differences in chemical profiles between groups, whereas the variable importance of the projection (VIP) spectrum (VIP > 1) and the trend plot of orthogonal partial least squares discriminant analysis were applied to intuitively screen the candidate variables present only in the dosed group. Consequently, by comparison with all the characterized components in vitro, 23 potential bioactive compounds were successfully identified, comprising 5 triterpenoids, 4 phathalides, 4 flavonoids, 4 organic acids, 3 lactones, and 3 other compounds, which were present in various medicinal materials, reflecting a synergistic mechanism. This work developed a rapid, reliable, and robust approach for comprehensive characterization of the chemical components and potential bioactive compounds of DSS, providing solid data for further research on pharmacodynamic substances and pharmacological mechanisms of DSS.
Race‐specific prostate cancer outcomes in a cohort of military health care beneficiaries undergoing surgery: 1990–2017
Authors: Oehrlein Nathan , Streicher Samantha A. , Kuo Huai‐Ching , Chaurasia Avinash , McFadden Jacob , Nousome Darryl , Chen Yongmei , Stroup Sean P. , Musser John , Brand Timothy , Porter Christopher , Rosner Inger L. , Chesnut Gregory T. , Onofaro Kayla C. , Rebbeck Timothy R. , D’Amico Anthony , Lu‐Yao Grace , Cullen Jennifer
Published: May 2022

Background

There is substantial variability in prostate cancer (PCa) mortality rates across Caucasian American (CA), African American (AA), Asian, and Hispanic men; however, these estimates are unable to disentangle race or ethnicity from confounding factors. The current study explores survival differences in long‐term PCa outcomes between self‐reported AA and CA men, and examines clinicopathologic features across self‐reported CA, AA, Asian, and Hispanic men.

Methods

This retrospective cohort study utilized the Center for Prostate Disease Research (CPDR) Multi‐center National Database from 1990 to 2017. Subjects were consented at military treatment facilities nationwide. AA, CA, Asian, or Hispanic men who underwent radical prostatectomy (RP) for localized PCa within the first year of diagnosis were included in the analyses. Time from RP to biochemical recurrence (BCR), BCR to metastasis, and metastasis to overall death were evaluated using Kaplan–Meier unadjusted estimation curves and adjusted Cox proportional hazards regression.

Results

This study included 7067 men, of whom 5155 (73%) were CA, 1468 (21%) were AA, 237 (3%) were Asian, and 207 (3%) were Hispanic. AA men had a significantly decreased time from RP to BCR compared to CA men (HR = 1.25, 95% CI = 1.06–1.48, p = 0.01); however, no difference was observed between AA and CA men for a time from BCR to metastasis (HR = 0.73, 95% CI = 0.39–1.33, p = 0.302) and time from metastasis to overall death (HR = 0.67, 95% CI = 0.36–1.26, p = 0.213).

Conclusions

In an equal access health care setting, AA men had a shorter survival time from RP to BCR, but comparable survival time from BCR to metastasis and metastasis to overall death.
A novel DNA methylation‐driver gene signature for long‐term survival prediction of hepatitis‐positive hepatocellular carcinoma patients
Authors: Fu Jie , Qin Wei , Tong Qing , Li Zhenghao , Shao Yaoli , Liu Zhiqiang , Liu Chun , Wang Zicheng , Xu Xundi
Published: May 2022

Background

Abnormal DNA methylation is one of the most general epigenetic modifications in hepatocellular carcinoma (HCC). Recent research showed that DNA methylation was a prognostic indicator of all‐cause HCC and nonviral HCC. However, whether DNA methylation‐driver genes could be used for predicting survival, the probability of hepatitis‐positive HCC remains unclear.

Methods

In this study, DNA methylation‐driver genes (MDGs) were screened by a joint analysis of methylome and transcriptome data of 142 hepatitis‐positive HCC patients. Subsequently, a prognostic risk score and nomogram were constructed. Finally, correlation analyses between the risk score and signaling pathways and immunity were conducted by GSVA and CIBERSORT.

Results

Through random forest screening and Cox progression analysis, 10 prognostic methylation‐driver genes (AC008271.1, C11orf53, CASP8, F2RL2, GBP5, LUCAT1, RP11‐114B7.6, RP11‐149I23.3, RP11‐383 J24.1, and SLC35G2) were screened out. As a result, a prognostic risk score signature was constructed. The independent value of the risk score for prognosis prediction were addressed in the TCGA‐HCC and the China‐HCC cohorts. Next, clinicopathological features were analyzed and HBV status and histological grade were screened to construct a nomogram together with the risk score. The prognostic efficiency of the nomogram was validated by the calibration curves and the concordance index (C index: 0.829, 95% confidence interval: 0.794–0.864), while its clinical application ability was confirmed by decision curve analysis (DCA). At last, the relationship between the risk score and signaling pathways, as well as the correlations between immune cells were elucidated preliminary.

Conclusions

Taken together, our study explored a novel DNA methylation‐driver gene risk score signature and an efficient nomogram for long‐term survival prediction of hepatitis‐positive HCC patients.
The association between single nucleotide polymorphisms and ovarian cancer risk: A systematic review and network meta‐analysis
Authors: Hu Jia , Xu Zhe , Ye Zhuomiao , Li Jin , Hao Zhinan , Wang Yongjun
Published: May 2022

Background

The relationship between single nucleotide polymorphisms (SNPs) and ovarian cancer (OC) risk remains controversial. This systematic review and network meta‐analysis was aimed to determine the association between SNPs and OC risk.

Methods

Several databases (PubMed, EMBASE, China National Knowledge Infrastructure, Wanfang databases, China Science and Technology Journal Database, and China Biology Medicine disc) were searched to summarize the association between SNPs and OC published throughout April 2021. Direct meta‐analysis was used to identify SNPs that could predict the incidence of OC. Ranking probability resulting from network meta‐analysis and the Thakkinstian’s algorithm was used to select the most appropriate gene model. The false positive report probability (FPRP) and Venice criteria were further tested for credible relationships. Subgroup analysis was also carried out to explore whether there are racial differences.

Results

A total of 63 genes and 92 SNPs were included in our study after careful consideration. Fok1 rs2228570 is likely a dominant risk factor for the development of OC compared to other selected genes. The dominant gene model of Fok1 rs2228570 (pooled OR = 1.158, 95% CI: 1.068–1.256) was determined to be the most suitable model with a FPRP <0.2 and moderate credibility.

Conclusions

Fok1 rs2228570 is closely linked to OC risk, and the dominant gene model is likely the most appropriate model for estimating OC susceptibility.
Comparative Content, Biological and Anticancer Activities of Heracleum humile Extracts Obtained by Ultrasound‐Assisted Extraction Method
Authors: Ocal Mustafa , Altunoglu Yasemin Celik , Angeloni Simone , Mustafa Ahmed M. , Caprioli Giovanni , Zengin Gokhan , Paksoy Mehmet Yavuz , Baloglu Mehmet Cengiz
Published: May 2022

As the safety and effectiveness of synthetic drugs remain in doubt, researchers are trying to develop natural medicines from medicinal plants. Herein, ethyl acetate, methanol and water extracts from the Heracleum humile plant were obtained by an ultrasonic‐assisted extraction process and the aim was to evaluate some biological effects of the extracts due to the limited data on the pharmacological properties of Heracleum humile in the literature. Weak antibacterial activity was observed on tested bacterial species. The minimum inhibitory concentration and the minimum bactericidal concentration values ranged from 250 to 500 μg/mL. In addition, cytotoxic activity was determined using the MTT test. The strongest findings were determined for ethyl acetate extract on the MDA‐MB‐231 cell lines at the 48th hour (IC50:97.94 μg/mL), followed by the MCF‐7 cell lines at the 24th hour (IC50:103.9 μg/mL). All extracts of Heracleum humile contained mainly flavonoids, phenolic acids and their derivatives, i. e., well‐known compounds that possess numerous biological activities such as antioxidant, anti‐inflammatory, anticancer, antimicrobial etc. The study results could provide important information that Heracleum humile could be a potential candidate as a natural enzyme inhibitor. It can be concluded that these extracts could be useful in the elementary step of improving novel plant‐derived multifunctional pharmaceuticals.
Why Omicron Variant of SARS‐CoV‐2 is Less Fatal?
Authors: Liao Lipeng , Zhang Jiaming , Wang Yuchuan , Liu Qiuyun
Published: May 2022

The article published by Nie et al. addressed one of the two key questions regarding the Omicron variant of SARS‐CoV‐2, while the underpinning for the less deadly nature of the variant remains unexplained. The proteins of the Omicron variant have numerous mutations, notably several substitutions of other amino acids by lysine residues. Glycine and valine attract calcium and enhance the formation of stressful, insoluble, and stiff calcium oxalate. Lysine residues in proteins build up chloride via ionic bonds which solubilizes insoluble and rigid divalent salts. The aforementioned mutations have weakened the lethalness of the Omicron variant perhaps via a biochemical mechanism. Despite net gain in favorable mutations versus deleterious mutations, the overall valine plus glycine content is still high in the proteins of Omicron variant of SARS‐CoV‐2, which remains a public health concern.
Colorimetric High‐Throughput Screening Method for Directed Evolution of Prazole Sulfide Monooxygenase
Authors: Liu Feng , Geng Qiang , Zhao Chen , Ren Shi‐Miao , Yu Hui‐Lei , Xu Jian‐He
Published: May 2022

Baeyer‐Villiger monooxygenases (BVMOs) are important biocatalysts for the enzymatic synthesis of chiral sulfoxides, including chiral sulfoxide‐type proton pump inhibitors for the treatment of gastrointestinal diseases. However, native BVMOs are not yet suitable for practical application due to their unsatisfactory activity and thermostability. Although protein engineering approaches can help address these issues, few feasible high‐throughput methods are available for the engineering of such enzymes. Herein, a colorimetric detection method to distinguish sulfoxides from sulfides and sulfones was developed for prazole sulfide monooxygenases. Directed evolution enabled by this method has identified a prazole sulfide monooxygenase CbBVMO variant with improved activity and thermostability that catalyzes the asymmetric oxidation of lansoprazole sulfide. A 71.3 % increase in conversion and 6 °C enhancement in the melting point were achieved compared with the wild‐type enzyme. This new method is feasible for high‐throughput screening of prazole sulfide monooxygenase variants with improved activity, thermostability, and/or substrate specificity.
Identification of the genetic central dogma in osteogenic differentiation of MSCs by osteoinductive medium from transcriptional data sets
Authors: Jiang Tong‐Meng
Published: May 2022

Background

The genetic central dogma (GCD) has been demonstrated its essential function in many biological processes and diseases. However, its roles in the process of osteogenic differentiation of mesenchymal stem cells (MSCs) remain unclear.

Methods

In this project, we analyzed an online database of osteogenic differentiation of MSCs after 14 days and 28 days by osteoinductive medium (GSE83770). The differentially expressed genes were screened by GEO2R, with further conducting of KEGG pathways using DAVID. In addition, protein–protein interactions of the enriched pathways were performed using STRING with marked hub genes measured by the CytoHubba. Hub genes were verified by quantitative reverse‐transcription polymerase chain reaction.

Results

Results showed that six pathways related to GCD, including DNA replication, Aminoacyl‐tRNA biosynthesis, Mismatch repair, Ribosome, Spliceosome, and RNA degradation pathways enriched in the early stage (14 days vs. undifferentiated MSCs) of osteogenesis. The Lysosome pathway was highly enriched in the late stage (28 vs. 14 days) of osteogenesis, and Ribosome pathway plays a key role throughout the entire process (28 days vs. undifferentiated MSCs) of osteogenesis.

Conclusion

Both DNA replication and protein translation were functionally worked in the early stage of osteogenesis, whereas the Lysosome pathway was the only GCD‐related one in the late stage of osteogenesis. The GCD‐related Ribosome pathway occupied the entire process of osteogenesis.
Grayscale image statistics of COVID‐19 patient CT scans characterize lung condition with machine and deep learning
Authors: Ghashghaei Sara , Wood David A. , Sadatshojaei Erfan , Jalilpoor Mansooreh
Published: May 2022

Background

Grayscale image attributes of computed tomography (CT) of pulmonary scans contain valuable information relating to patients with respiratory ailments. These attributes are used to evaluate the severity of lung conditions of patients confirmed to be with and without COVID‐19.

Method

Five hundred thirteen CT images relating to 57 patients (49 with COVID‐19; 8 free of COVID‐19) were collected at Namazi Medical Centre (Shiraz, Iran) in 2020 and 2021. Five visual scores (VS: 0, 1, 2, 3, or 4) are clinically assigned to these images with the score increasing with the severity of COVID‐19‐related lung conditions. Eleven deep learning and machine learning techniques (DL/ML) are used to distinguish the VS class based on 12 grayscale image attributes.

Results

The convolutional neural network achieves 96.49% VS accuracy (18 errors from 513 images) successfully distinguishing VS Classes 0 and 1, outperforming clinicians’ visual inspections. An algorithmic score (AS), involving just five grayscale image attributes, is developed independently of clinicians’ assessments (99.81% AS accuracy; 1 error from 513 images).

Conclusion

Grayscale CT image attributes can be successfully used to distinguish the severity of COVID‐19 lung damage. The AS technique developed provides a suitable basis for an automated system using ML/DL methods and 12 image attributes.
An Introduction to the Combustion of Carbon Materials
Authors: Picheau Emmanuel , Amar Sara , Derré Alain , Pénicaud Alain , Hof Ferdinand
Published: May 2022

Combustion is arguably as old as homo sapiens ability to observe and use fire. Despite the long tradition of using carbon combustion for energy production, this reaction is still not fully understood. This can be related to several facts that are intertwined and complicate the investigation, such as the large variety of possible carbon structures, the actual surface structure, porosity, the solid‐gas nature of this reaction, diffusion limitation and fundamental reaction steps. In this review, a brief history of carbon combustion science is given, followed by a detailed discussion of the most important aspects of carbon combustion. Special attention is given to limitations for example diffusion. In carbon combustion, kinetic control can rarely be observed. The literature of the fundamental reaction steps actually occurring on the carbon framework is reviewed and it becomes apparent that the reaction is occurring primarily on defects on the basal plane. Thus, the reaction between oxygen and carbon may be used as an analytical tool to provide further insights into novel materials, for example synthetic carbon materials, fibres and graphene type materials. Mastering the combustion reaction in all its complexity may prove to be very valuable in the future.