bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantum mechanics and symmetries
Authors: Wess J.
Published: May 2022

Symmetries have always played an important role in physics. With quantum mechanics, however, the interplay between physics and symmetries has reached a new dimension. The very structure of quantum mechanics invites the application of group theoretical methods to an extent that physicists would have been led to invent various concepts of group theory, such as Lie groups, by quantum mechanics had they not been known before.

Symmetries are also a direct mediator between experimental facts and the theoretical structure of a theory. This is the case because there is a direct connection between symmetries and conservation laws. Space‐time symmetries are an obvious example. Conservation of energy, momentum and angular momentum are linked to invariance under time translation, space translation and rotation in space.

It was in atomic physics that space‐time symmetries became significant, but they are as important in nuclear physics and in all the physics discovered after that. In nuclear physics, however, a new concept of symmetries, symmetries in an internal space, was discovered with the introduction of isospin. All our socalled fundamental models describing what we know about strong‐weak and electromagnetic interactions are built on symmetries in space‐time and internal spaces. These symmetries are not only used to extract information from a theory, they are also used to construct these theories, and this for good reasons. It turned out that only theories possessing such symmetries make sense as quantum field theories. Thus symmetries are not only a good tool to deal with quantum field theoretical models, they are necessary to define such models.

Following this line of thought, a new type of symmetry, the socalled supersymmetry, proved to be extremely successfull. Quantum theory seems to have a very deep relation to supersymmetry. Thus it is not surprising that the most promising fundamental models of physics are based on supersymmetry, even when they go beyond a local quantum field theory, as string theory does.
Continuities and discontinuities in Planck's Akt der Verzweiflung
Authors: Darrigol O.
Published: May 2022

Planck's famous communication of December 1900 cannot be understood without taking into account an essential difference between his and Boltzmann's conceptions of the relation between micro‐ and macro‐world. For Boltzmann, macroscopic laws were in principle completely determined by the underlying microscopic dynamics. For Planck, the microscopic dynamics were partly undetermined and had to be supplemented by additional assumptions in order to reach macroscopic laws.Thanks to this leeway, Planck could introduce finite energy‐elements and derive his famous black‐body law without giving up the continuity and determinism of former dynamical theories. The purpose of this paper is to explain the origins, peculiarities, and evolution of Planck's approach; to show how it ultimately yielded the correct black‐body law; and to examine the status of the energy‐elements which Planck thereby introduced.
Photoemission spectroscopy in solids
Authors: Chiang T.‐C. , Seitz F.
Published: May 2022

The photoelectric effect was discovered and explained in terms of quantum physics about a hundred years ago. Today, photoemission spectroscopy using vacuum ultraviolet radiation and x‐rays is an important tool for studying the electronic properties and atomic structure of solids. This paper reviews the development of an understanding of the photoemission process and the basic applications of photoemission spectroscopy in solids, including band structure determination, studies of quasiparticle properties, and core level spectroscopy.
Matter‐antimatter asymmetry of the universe
Authors: Buchmüller W.
Published: May 2022

The asymmetry of the universe between matter and antimatter in the universe is related to neutrino properties due to non‐perturbative processes in the high‐temperature symmetric phase of the standard model. We show that the neutrino masses inferred from the solar and atmospheric neutrino anomalies are consistent with the hypothesis that the observed cosmological matter density has been created in decays of heavy Majorana neutrinos in the early universe.
Finite renormalizations in the Epstein Glaser framework and renormalization of the S‐matrix of Φ4‐theory
Authors: Pinter Gudrun
Published: May 2022

A formula describing finite renormalizations is derived in the Epstein‐Glaser formalism and an explicit calculation of finite counterterms in Φ4‐theory is performed. The Zimmermann identities and the action principle for changes of parameters in the interaction are presented independent of the adiabatic limit.
Hamiltonian structure and gauge symmetries of Poincaré gauge theory
Authors: Bagojević M.
Published: May 2022

This is a review of the constrained dynamical structure of Poincaré gauge theory which concentrates on the basic canonical and gauge properties of the theory, including the identification of constraints, gauge symmetries and conservation laws. As an interesting example of the general approach, we discuss the teleparallel formulation of general relativity.
Quantum diffusion and scaling of localized interacting electrons
Authors: Halfpap Ole
Published: May 2022

A new numerical method is introduced that enables a reliable study of disorder‐induced localization of interacting particles. It is based on a quantum mechanical time evolution calculation combined with a finite size scaling analysis. The time evolution of up to four particles in one dimension is studied and localization lengths are defined via the long‐time saturation values of the mean radius, the inverse participation ratio and the center of mass extension. A systematic study of finite size effects using the finite size scaling method is performed in order to extract the localization lengths in the limit of an infinite system size. For a single particle, the well‐known scaling of the localization length λ1 with disorder strength W is observed, λ1 ∝ W—2. For two particles, an interaction‐induced delocalization is found, confirming previous results obtained by numerically calculating matrix elements of the two‐particle Green's function: in the limit of small disorder, the localization length increases with decreasing disorder as λ2 ∝ W—4 and can be much larger than <$>\mitlambda λ1. For three and four particles, delocalization is even stronger. Based on analytical arguments, an upper bound for the n‐particle localization length λn is derived and shown to be in agreement with the numerical data, λn ∝ λ1. Although the localization length increases superexponentially with particle number and can become arbitrarily large for small disorder, it does not diverge for finite λ1 and n. Hence, no extendedstates exist in one dimension, at least for spinless fermions.
Dimple‐assisted dewetting: heterogeneous nucleation in undercooled wetting films
Authors: Blossey Ralf
Published: May 2022

Undercooled wetting films near a first‐order wetting transition exhibit an unusually long lifetime: the thermal nucleation barrier for formation of a critical hole in a film of thickness F diverges according to Γ ∼ exp (ℰc/kBT) where the excess free energy ℰc ∼ Fζ with ζ ≥ 2. Localized perturbations of the liquid‐vapor interface (‘dimples’) are shown to be a useful tool in reducing Γ in a controlled way: they act as heterogeneous nucleation centers for thermal critical nuclei. For 4He wetting films on weak‐binding alkali substrates (Cs, Rb) dimples can be generated either by vortices in a superfluid film or by surface electrons. The theory of the heterogeneous nucleation process initiated by the presence of surface dimples (‘dimple‐assisted dewetting’) is developed, accompanied by quantitative predictions for experiment.
Fluctuation effects in disordered Peierls systems
Authors: Bartosch Lorenz
Published: May 2022

We review the density of states (DOS) and related quantities of quasi one‐dimensional disordered Peierls systems in which fluctuation effects of a backscattering potential play a crucial role. The low‐energy behavior of non‐interacting fermions which are subject to a static random backscattering potential will be described by the strictly one‐dimensional fluctuating gap model (FGM). Recently, the FGM has also been used to explain the pseudogap phenomenon in high‐Tc superconductors. We develop a non‐perturbative method which allows for a simultaneous calculation of the DOS and inverse localization length for an arbitrary given disorder potential by solving a simple initial value problem. In the white noise limit, we recover all known results by solving a Fokker‐Planck equation. For the physically interesting case of finite correlation lengths, we use analytical and numerical methods to show that a complex order parameter leads to a suppression of the DOS, i.e. a pseudogap, and that for a real order parameter this pseudogap is overshadowed by a singularity in the DOS. We will also consider the case of classical phase fluctuations which applies to low temperatures where amplitude fluctuations are frozen out. For this regime we present analytic results for the DOS, the inverse localization length, the specific heat, and the Pauli susceptibility.
Wave phenomena in low‐rate plastic flow of solids
Authors: Zuev Lev B.
Published: May 2022

An investigation of plastic flow localization patterns (waves) which are ordered in space and evolve with time has been performed for a wide range of metals and alloys. These waves are found to have the following basic features: the dependence of propagation rate on work hardening coefficient, dispersion law and scale effect. The possibility of addressing plastic flow localization as a self‐organization process occurring in a deforming medium is considered. A set of equations appropriate for the description of local flow nuclei is discussed. Consideration is given to a change‐over from one local strain pattern to another in accordance with the respective stages of flow. Proposed is a model for interpreting the large‐scale periodicities exhibited by the distribution of localized strain nuclei.
Many‐body Green's function theory for thin ferromagnetic films: exact treatment of the single‐ion anisotropy
Authors: Fröbrich P. , Kuntz P.J. , Saber M.
Published: May 2022

A theory for the magnetization of ferromagnetic films is formulated within the framework of many‐body Green's function theory which considers all components of the magnetization. The model Hamiltonian includes a Heisenberg term, an external magnetic field, a second‐ and fourth‐order uniaxial single‐ion anisotropy, and the magnetic dipole‐dipole coupling. The single‐ion anisotropy terms can be treated exactlyby introducing higher‐order Green's functions and subsequently taking advantage of relations between products of spin operators which leads to an automatic closure of the hierarchy of the equations of motion for the Green's functions with respect to the anisotropy terms. This is an improvement on the method of our previous work, which treated the corresponding terms only approximately by decoupling them at the level of the lowest‐order Green's functions. RPA‐like approximations are used to decouple the exchange interaction terms in both the low‐order and higher‐order Green's functions. As a first numerical example we apply the theory to a monolayer for spin S = 1 in order to demonstrate the superiority of the present treatment of the anisotropy terms over the previous approximate decouplings.
Ring currents effect on the dielectric function of cylindrical nano‐organic materials
Authors: Pleutin Stéphane , Ovchinnikov Alexander
Published: May 2022

We review recent results on the behaviour of the dielectric function of cylindrical nano‐organic materials at very low frequencies in a magnetic field. For cylindrical structures — such as carbon nanotubes — the polarisability is shown to be a discontinuous function of a longitudinal magnetic field where plateau‐like regions are separated by sudden jumps or peaks. A relation is pointed out between each discontinuity in the polarisability and the cross‐over between ground and first excited states induced by the magnetic field. This one to one correspondence suggests to use measurements of the dielectric function in an applied magnetic field in order to obtain informations about the electronic structures of cylindrical nanostructures. In addition, it is shown, by studying finite graphene layers, that the measurement of the polarisability in a magnetic field could be a powerful way for detecting possible edge‐states in amorphous carbon materials such as activated carbon fibres. Finally, the importance of the electron‐electron interaction is emphasised by discussing examples of strongly interacting electrons on rings or cylinders, in the limit of infinite interaction.
Infrared absorption spectra studies in (NaNO3–NaNO2) system
Authors: Hammad Talaat Moussa
Published: May 2022

A complete infrared study of the mixed crystal system of NaNO3 and NaNO2 is carried out in the region 600—3000 cm—1 at room temperature. The study includes fundamental internal normal vibrations of the NO—2 and NO—3 ions. The IR spectra, spectral band shape intensities, combination modes, and frequencies of the internal modes were studied as a function of NO—3 ion concentration. Special attention is paid to the bending mode, the combination mode, and a symmetric stretching mode.
Do gravitational waves carry energy‐momentum and angular momentum?
Authors: Garecki Janusz
Published: May 2022

We show that gravitational waves which possess a non‐vanishing Riemann tensor Riklm ≠ 0 always carry energy‐momentum and angular momentum. Our proof uses canonical superenergy and supermomentum tensors for the gravitational field.
Neutrino masses and particle physics beyond the standard model
Authors: Päs H.
Published: May 2022

The evidence for non‐vanishing neutrino masses from solar and atmospheric neutrinos provides the first solid hint towards physics beyond the standard model. A full reconstruction of the neutrino spectrum may well provide a key to the theoretical structures underlying the standard model such as supersymmetry, grand unification or extra space dimensions. In this article we discuss the impact of absolute neutrinos masses on physics beyond the standard model. We review the information obtained from neutrino oscillation data and discuss the prospects of the crucial determination of the absolute neutrino mass scale, as well as the intriguing connection with the Z‐burst model for extreme‐energy cosmic rays.
A supersymmetric extension of quantum gauge theory
Authors: Grigore D.R. , Scharf G.
Published: May 2022

We consider a supersymmetric extension of quantum gauge theory based on a vector multiplet containing supersymmetric partners of spin 3/2 for the vector fields. The constructions of the model follows closely the usual construction of gauge models in the Epstein‐Glaser framework for perturbative field theory. Accordingly, all the arguments are completely of quantum nature without reference to a classical supersymmetric theory. As an application we consider the supersymmetric electroweak theory. The resulting self‐couplings of the gauge bosons agree with the standard model up to a divergence.
The temperature dependence of saturation magnetization of γ‐Fe2O3/SiO2 magnetic nanocomposite
Authors: Caizer C. , Hrianca I.
Published: May 2022

The saturation magnetization of ferrimagnetic nanoparticles of γ‐Fe2O3 that are isolated in an amorphous SiO2 matrix, has a high increase when the temperature decreases from 300 to 77K. In this case, the relative variation (69.7 magnetization corresponding to bulk ferrite (9.5 is attributed to the narrowing of the paramagnetic layer that exists at the surface of nanoparticles; with the decrease of temperature, the mean magnetic diameter, and implicitly the magnetic moment of the particles increases, which in turn leads to an increase of the saturation magnetization. The existence of the paramagnetic layer is a result of the modification of the superexchange interaction between iron ions at the nanoparticle surface, due to the distortion of the crystalline network in the presence of the silica matrix. Based on the experimental results we propose a core‐shell model that explains the abnormal increase of the saturation magnetization of γ‐Fe2O3 nanoparticles dispersed in a silica matrix compared to bulk γ‐Fe2O3.
Graftable voltage stabilizer for enhancing insulation performance of crosslinked polyethylene
Authors: Ren Yuanyuan , Deng Wei , Li Wanyu , Zhao Hong
Published: May 2022

With the popular application of alternating current/direct current (AC/DC) hybrid power grid, ultra‐high‐voltage (UHV) AC/DC cables of long‐distance and large‐capacity transmission systems have been strongly demanded. Voltage stabilizers are widely used to resist AC electrical tree of cross‐linked polyethylene (XLPE) insulation materials, but poor compatibility with polymer matrix limited improvement of DC insulation performance. In this research, the maleic anhydride‐modified 2,4‐dihydroxybenzophenone as a novel voltage stabilizer 4‐(4‐benzoyl‐3‐hydroxyphenoxy)‐4‐oxobut‐2‐enoic acid (MDVS) was synthesized to improve the electrical properties of XLPE. The XLPE‐g‐MDVS with different contents of MDVS was prepared, and both AC electrical properties and DC electrical properties were tested. The results indicate that the modified XLPE retain the characteristic of voltage stabilizer to resist AC electrical tree and improve breakdown strength, and to exhibit excellent DC insulation performance in a wide temperature range. In the comparison with the pristine XLPE, the graft of MDVS can significantly suppress space charge accumulation and decrease DC conductivity. At 70°C, the maximum amount of space charge density of XLPE‐g‐1.2wt%MDVS is 56.2% lower than that of XLPE, and the DC conductivity decreases by nearly two orders of magnitude. Furthermore, the DC breakdown strength of XLPE‐g‐1.2wt%MDVS materials exhibit higher than that of the pristine XLPE. In addition to the self‐excited energy dissipation of the voltage stabilizer, quantum chemical calculations demonstrated that the improvement of DC performance attributed to the deep traps introduced by MDVS.
Atomically‐Dispersed Fe‐N4 on 3D Hierarchical Porous Carbon for High‐Performance Lithium‐Sulfur Battery
Authors: Bie Qin , Li Pingbo , Cheng Hua , Zheng Sijia , Yu Jin , Yu Lei , Wang Feng , Wu Rui , Chen Jingdong , Song Chen Jun
Published: May 2022

Lithium‐sulfur (Li−S) battery with the advantages of high theoretical capacity and low cost is a promising technology for advanced energy storage. However, poor conductivity of the sulfur cathode, huge volume expansion, shuttling effect and sluggish catalytic conversion of lithium polysulfide hinder its commercialization. Herein, a 3D hierarchical porous carbon loaded with atomically dispersed Fe‐N4 was developed as a sulfur cathode, which not only offers enhanced electronic conductivity, but also alleviates volume expansion. Moreover, density functional theory calculation results suggest that the Fe‐N4 sites are favorable to enhance the diffusion and promote the conversion of lithium polysulfide. Consequently, lithium‐sulfur battery with 3D hierarchical porous carbon as the sulfur cathode exhibit good capacity and cycling performance, where a high initial specific capacity of 1289.3 mAh g−1 can be delivered at 0.1 C, and a capacity loss of only 0.025 % per cycle can be achieved for 1000 cycles at 2.0 C.
Four Highly Oxygenated Sesquiterpenoids from the Fruits of Illicium micranthum Dunn
Authors: Lei Tie , Liu Zhen‐Xiang , Bao Yi , Ding Lin‐Fen , Song Liu‐Dong , Wu Xing‐De , Zhao Qin‐Shi
Published: May 2022

Four highly oxygenated sesquiterpenoids, illimicranolides A (1) and B (2), and illicinolides E (3) and F (4), were obtained from the fruits of Illicium micranthum Dunn, as well as one known analog, illicinolide B (5). The chemical structures of 1–4 were determined comprehensively by 1D (1H and 13C) and 2D (HMBC, HSQC, 1H‐1H COSY, and ROESY) NMR, and HR‐ESI‐MS data. Structurally, compound 1 was an unprecedented sesquiterpenoid with a 5/5/6/5‐fused tetracyclic ring system and was the first seco‐prezizaane sesquiterpenoid featuring a 11,8‐γ‐lactone ring. Compounds 3 and 4 were the fifth and sixth examples of illicinolide‐type sesquiterpenoids. Moreover, compound 1 demonstrated neurotrophic activity of NGF‐induced PC12 cells with differentiation rate of 10.34 % at a concentration of 10 μM.
Durability Study of 3D‐Printed Catalytic Static Mixers for Hydrogenations in Chemical Manufacturing
Authors: Legg Rob , Zhang Charles , Bourchier Michael , Cole Sarah , Martinez‐Botella Ivan , Nguyen Xuan , Zhu Yutong , Liew Winston , Saubern Simon , Tsanaktsidis John , Hornung Christian H.
Published: May 2022

Structured catalysts made by additive manufacturing offer the capability to seamlessly scale heterogeneous catalysis from lab to production with minimal effort to reengineer the process at intermediate steps. They can be tailored to meet certain process demands for mixing, heat transfer and flow resistance, in order to overcome flow maldistribution, hotspot or pressure drop issues, generally associated with traditional packed bed systems. Herein we investigate the long‐term durability of 3D‐printed Pd catalytic static mixers for their use in the hydrogenation of 4‐nitrobenzoic acid.
Multi‐institutional validation of a modified scheme for subcategorizing salivary gland neoplasm of uncertain malignant potential (SUMP)
Authors: Hang Jen‐Fan , Lee Jaslyn Jie Lin , Nga Min En , Higuchi Kayoko , Hirata Yukiya , Wu Howard H. , Allison Derek B. , Gilbert Jason D. , Lin Oscar , Saieg Mauro , de Arruda Arthur Ferrari , Chen Yun‐An , Huang Eric C. , Manucha Varsha
Published: May 2022

BACKGROUND

The salivary gland neoplasm of uncertain malignant potential (SUMP) category in the Milan System is diagnostically challenging. This study aims to validate a modified scheme for subcategorizing SUMP in a large multi‐institutional cohort.

METHODS

Retrospective review of salivary gland fine‐needle aspirations (FNAs) from 10 institutions were classified based on the Milan System. Cases diagnosed as SUMP with available cytology slides and surgical follow‐up were retrieved for review and subcategorized based on a modified scheme as follows: basaloid SUMP (B1: absent/scant nonfibrillary matrix; B2: presence of nonfibrillary/mixed‐type matrix), oncocytic/oncocytoid SUMP (O1: with mucinous background; O2: without mucinous background), and SUMP not otherwise specified (NOS).

RESULTS

A total of 742 (7.5%) cases from 9938 consecutive salivary gland FNAs were classified as SUMP. Among them, 525 (70.8%) had surgical follow‐up and 329 (62.7%) were available for review. The overall risk of malignancy (ROM) of SUMP was 40.4%. There were 156 cases (47.4%) subcategorized as basaloid SUMP with a ROM of 36.5%, 101 (30.7%) as oncocytic/oncocytoid SUMP with a ROM of 52.5%, and 72 (21.9%) as SUMP NOS with a ROM of 31.9%. The ROM of oncocytic/oncocytoid SUMP was significantly higher than basaloid SUMP (P = .0142) and SUMP NOS (P = .0084). No significant differences in ROM were noted between B1 and B2 (36.7% vs 36.4%, P = 1.0000) and O1 and O2 (65.2% vs 48.7%, P = .2349).

CONCLUSIONS

The ROM of oncocytic/oncocytoid SUMP was 52.5% and significantly higher than that of basaloid SUMP (36.5%, P = .0142) and SUMP NOS (31.9%, P = .0084), whereas no significant differences in ROM were noted for cases with different types of extracellular matrix or background material.;
CdS/VS2 Heterostructured Nanoparticles as Efficient Visible‐Light‐Driven Photocatalysts for Boosting Hydrogen Evolution
Authors: Niu Mengfan , Cao Liyun , Feng Liangliang , He Danyang , Li Xiaoyi , Chen Qian , Fu Changle , Huang Jianfeng
Published: May 2022

The development of highly active, cost‐effective hydrogen‐evolving photocatalysts is of great significance to alleviate the escalating environmental pollution and depleting fossil fuel sources. Herein, a novel CdS/VS2 heterostructured nanoparticle is successfully synthesized for the photocatalytic hydrogen evolution reaction (HER) under visible‐light irradiation via a facile hydrothermal route. Experimental results demonstrate that VS2 can facilitate the absorption of visible light, enhance the electron transfer rate, as well as inhibit the recombination of photogenerated electron‐hole pairs on CdS photocatalyst. Moreover, the optimal CdS/VS2 (0.2 wt.%) hybrid exhibits prominent photocatalytic HER activity 16 times higher than the pristine CdS counterpart, even outperforming the 1 wt.% platinum‐loaded CdS. This work injects new impetus to explore efficient noble‐metal‐free cocatalysts of CdS photocatalyst for high‐efficiency photocatalytic H2 evolution.
Experimental and Theoretical Evidence of a Pb⋅⋅⋅Pb Ditetrel Bond Without a σ‐Hole
Authors: Zierkiewicz Wiktor , Michalczyk Mariusz , Mahmoudi Ghodrat , García‐Santos Isabel , Castiñeiras Alfonso , Zangrando Ennio , Scheiner Steve
Published: May 2022

The crystal structure of a newly synthesized compound, [PbL(Ac)]2, (where L=2 (amino(pyrazin‐2‐yl) methylene) hydrazinecarbothioamide, Ac=acetate anion) exhibits a close contact between pairs of Pb atoms, suggesting a ditetrel bond, in addition to two Pb⋅⋅⋅O tetrel bonds, and two C−H⋅⋅⋅O H‐bonds. The presence of this ditetrel bond as an attractive component is confirmed by various quantum chemical methods. This novelty of this particular bond is its existence even in the absence of a σ‐hole on the Pb atom, which is typically considered a prerequisite for a bond of this type. From a wider perspective, a survey of the Cambridge Structural Database suggests this bond may be more common than was hitherto thought, with 44 examples of Pb⋅⋅⋅Pb contacts amongst a total number of 219 examples of T⋅⋅⋅T interactions in general (T=Si, Ge, Sn, Pb).
Dual Emission, Aggregation, and Redox Properties of Boron Difluoride Hydrazones Functionalized with Triphenylamines
Authors: Cappello Daniela , Buguis Francis L. , Boyle Paul D. , Gilroy Joe B.
Published: May 2022

π‐Conjugated molecular materials often exhibit interesting photoluminescence, redox, and optoelectronic properties that grant them utility as light‐harvesting materials in solar cells, as the emissive component of organic light‐emitting diodes, and as fluorescence sensors. Preparing dye conjugates by appending multiple dyes together to generate π‐conjugated molecules is a common strategy to enhance the properties of these materials as it often imparts traits that cannot be achieved by the building blocks independently. Herein, we report molecular materials that incorporate boron difluoride hydrazone (BODIHY) and triphenylamine (TPA) units that exhibit charge‐transfer character, dual‐emission, and aggregation‐induced emission. The title compounds have low‐energy absorption bands (λabs=455–493 nm) that are red‐shifted relative to BODIHYs with smaller π‐systems and exhibit dual‐emission in the solution, solid, and aggregate states. TPA–BODIHY (donor‐acceptor) conjugates show multiple reversible redox events and, in combination, the data presented herein indicate that there is electronic communication throughout the donor‐acceptor and acceptor‐donor‐acceptor π‐systems. These results are rationalized with the use of computational chemistry and solid‐state structural analysis. This study provides new opportunities for the design of molecular materials that are comprised of redox‐active photoluminescent dyes, including BODIHY, and their potential applications.
Hydrophobic Amplification Enabled High‐Turnover Phosphazene Superbase Catalysis
Authors: Lee Sun Bu , Park Jin Hyun , Bae Han Yong
Published: May 2022

β‐Sulfido sulfonyl fluoride and its derivatives have been gaining attention recently in the fields of medicinal chemistry and material science. The conventional method for the synthesis of functionalized alkyl sulfonyl fluorides requires several chemical transformations. Therefore, a direct establishment of such chemical structures remains challenging, and an efficient catalytic approach is highly desired. Herein a significant “on‐water” hydrophobic amplification was achieved, enabling a high‐turnover catalytic thia‐Michael addition to produce unprecedented β‐arylated‐β‐sulfido sulfonyl fluorides. Amounts as low as 100 ppm (0.01 mol %) of the phosphazene superbase were sufficient to successfully catalyze the reaction with excellent chemo‐/site‐selectivity and with optimal functional group tolerance. Several β‐arylated ethene sulfonyl fluorides were converted into thia‐Michael adducts up to >99 % yields. The mild conditions, high turnover, neutral pH, and scalability of the sustainable catalytic process benefit the preparation of potential pharmaceuticals (e. g., polyisoprenylated methylated protein methyl esterase inhibitors) and organic materials (e. g., electrolyte additives).
Persistence of a Ru3(μ‐CO)3(CO)5Cluster Bound to a PNNP “Expanded Pincer” Ligand in Different Protonation States
Authors: van Beek Cody B. , Killian Lars , Lutz Martin , Broere Daniël L. J.
Published: May 2022

We report the synthesis and characterization of Ru3(μ‐CO)3(CO)5‐type cluster complexes bound to a dinucleating PNNP ‘expanded pincer’ ligand. Each bidentate PN pocket of the ligand chelates a single ruthenium center of the cluster and can undergo deprotonation concomitant with dearomatization of its naphthyridine core. Although the cluster bearing a partially dearomatized ligand reacts with H2, we found no indication that this proceeds via a pathway involving metal‐ligand cooperativity.
Aerobic Baeyer‐Villiger Oxidation Catalyzed by Metal Corroles
Authors: Li Meng‐Ni , Wan Bei , Yang Shuang , Tang Yan , Zhang Hao , Zhang Si‐Quan , Liu Hai‐Yang , Ye Yong
Published: May 2022

Metal corrole catalyzed Baeyer‐Villiger oxidation reaction was successfully achieved for the first time. Among all tested Co, Mn, Fe and Cu complexes of 5, 10, 15‐Tris (pentafluorophenyl) corrole, Fe complex [Fe(tpfc)Cl] exhibited the best activity, and the highest yield was observed for six membered cyclic ketones. Preliminary results suggest that Fe(tpfc)Cl may act as an initiator for dehydrogenation of benzaldehyde to generate benzoyl radical, which will form peroxybenzoic acid under molecular oxygen atmosphere. The oxidation of Fe(tpfc)Cl catalyst by peroxybenzoic acid produces high‐valent iron‐oxo corrole intermediate. The iron‐oxo corrole is attacked by cyclohexanone to form a Criegee adduct, which will finally generate ϵ‐caprolactone product to finish the catalytic cycle. The 4 A‐MS additive may accelerate the production of perbenzoic acid and significantly improve the reaction yield.
What about parents? A systematic review of paediatric intensive interdisciplinary pain treatment on parent outcomes
Authors: Harbeck‐Weber Cynthia , Sim Leslie , Morrow Allison S. , Murad M. Hassan
Published: May 2022

Background and Objective

Intensive interdisciplinary pain treatment (IIPT) for youth with high impact chronic pain has been found to be effective in improving child symptoms and functioning. However, it remains unclear how these interventions impact the parents' own well‐being, as well as cognitions and behaviours which are known to influence child pain and functioning. Thus, the current study sought to determine the effect of IIPT on parent mental health, cognitions and behaviours in parents of youth attending IIPT with their child.

Databases and Data Treatment

A search of the electronic databases CINAHL, Ovid EBM Reviews, Embase, Medline, APA PsychINFO, Scopus and web of Science was conducted. Studies were included if they comprised at least 10 parents of patients aged 9–22 with nonmalignant chronic pain attending an IIPT and were written in English.

Results

A random‐effects model was used to pool the standardized mean change (SMC) across seven prepost studies. At discharge, IIPT participation was associated with small to moderate improvements in direct parental outcomes (general mental health, anxiety, depression and parenting stress), a moderate improvement in pain catastrophizing and large improvements in psychological flexibility and parenting behaviours. Most improvements were maintained at follow‐up. The risk of bias of all studies was rated as serious and the certainty of the evidence as low, suggesting limited confidence in the estimates.

Conclusions

Although parents appear to benefit from attending an IIPT with their child, RCTs are needed to substantiate the effect of these interventions on important aspects of parent well‐being and functioning.
Short‐term commercial load forecasting based on peak‐valley features with the TSA‐ELM model
Authors: Zhou Mengran , Zhu Ziwei , Hu Feng , Bian Kai , Lai Wenhao , Hu Tianyu
Published: May 2022

Commercial buildings are consuming an increasing amount of energy, and accurate load demand forecasting is critical for the reliable operation of power systems and the efficient use of resources. Therefore, in this paper, a short‐term commercial load forecasting model based on tunicate swarm algorithm (TSA) combined with an extreme learning machine (ELM) under peak‐valley features is proposed as a research case for a shopping mall in Romania. This paper's overall structure is divided into two steps. In the first step, the 24‐h day is divided into six periods by analyzing the daily load characteristics of the training set, and the peak and valley loads are obtained. The ELM optimized by TSA (TSA‐ELM) algorithm is then used to forecast the peak and valley values of the test set one day ahead. In the second step, the actual load, peak, and valley for the previous week of historical load are chosen using the maximum information coefficient (MIC). Following that, the MIC ≥ 0.8 features are added to the TSA‐ELM to achieve short‐term commercial electricity load forecasting. The results show that the PV (Peak & Valley)‐TSA‐ELM model proposed in this paper has higher prediction accuracy compared with other models. Taking ELM as an example, compared with the traditional ELM, the mean absolute error, root mean square error, and mean absolute percentage error of PV‐TSA‐ELM are reduced by 20.59%, 20.13%, and 19.19% on average in the three commercial data sets. The proposed model is validated with an industrial data set, and ideal results are obtained, which verifies the effectiveness and superiority of the proposed method.
Analyses of the spatial and temporal features of the blade pressure‐side cavitation in a pump‐turbine runner in the pump mode
Authors: Tao Ran , Jin Faye , Wu Yanzhao , Lu Zhaoheng , Xiao Ruofu , Zhu Di , Liu Weichao
Published: May 2022

In the pump mode of pump‐turbine, cavitation usually happens in runners because of the local pressure drop on the blade leading‐edge. At over‐load, pressure drop and cavitation occur on the runner blade pressure side. In conventional studies, the spatial and temporal features of the blade pressure‐side cavitation are difficult to understand. In this study, the runner blade pressure‐side cavitation is studied in a pump‐turbine in pump mode at over‐load. Local low pressure and cavitation are found on runner blade pressure‐side at leading‐edge near shroud. Moreover, small‐scale gathering cavitation is also observed on the blade suction‐side with connecting the large‐scale pressure side cavity. As a breakthrough in flow analysis, the pulsation tracking network (PTN) method is applied to track the spatial and temporal features of cavitation. The time‐accumulated intensity, pulsation amplitude, frequency, and phase are analyzed for cavitation based on PTN. The stably‐gathering strong‐intensity cavitation sites are indicated by time‐accumulated intensity. Based on the pulsation amplitude contour, strong pulsating cavitation is found on the edges of the gathering strong cavities. Frequency and phase analyses indicate the cavitation propagation along the blade‐to‐blade direction and reveal the reason of the connecting cavitation phenomenon. The spatial and temporal features of cavitation is well investigated.
Mitochondrial E3 ubiquitin ligase 1 (MUL1) as a novel therapeutic target for diseases associated with mitochondrial dysfunction
Authors: Calle Ximena , Garrido‐Moreno Valeria , Lopez‐Gallardo Erik , Norambuena‐Soto Ignacio , Martínez Daniela , Peñaloza‐Otárola Allan , Troncossi Angelo , Guerrero‐Moncayo Alejandra , Ortega Angélica , Maracaja‐Coutinho Vinicius , Parra Valentina , Chiong Mario , Lavandero Sergio
Published: May 2022

Mitochondrial E3 ubiquitin ligase 1 (MUL1) is a mitochondrial outer membrane‐anchored protein‐containing transmembrane domain in its N‐ and C‐terminal regions, where both are exposed to the cytosol. Interestingly the C‐terminal region has a RING finger domain responsible for its E3 ligase activity, as ubiquitin or in SUMOylation, interacting with proteins related to mitochondrial fusion and fission, cell survival, and tumor suppressor process, such as Akt. Therefore, MUL1 is involved in various cellular processes, such as mitochondrial dynamics, inter‐organelle communication, proliferation, mitophagy, immune response, inflammation and cell apoptosis. MUL1 is expressed at a higher basal level in the heart, immune system organs, and blood. Here, we discuss the role of MUL1 in mitochondrial dynamics and its function in various pathological models, both in vitro and in vivo. In this context, we describe the role of MUL1 in: (1) the inflammatory response, by regulating NF‐κB activity; (2) cancer, by promoting cell death and regulating exonuclear function of proteins, such as p53; (3) neurological diseases, by maintaining communication with other organelles and interacting with proteins to eliminate damaged organelles and; (4) cardiovascular diseases, by maintaining mitochondrial fusion/fission homeostasis. In this review, we summarize the latest advances in the physiological and pathological functions of MUL1. We also describe the different substrates of MUL1, acting as a positive or negative regulator in various pathologies associated with mitochondrial dysfunction. In conclusion, MUL1 could be a potential key target for the development of therapies that focus on ensuring the functionality of the mitochondrial network and, furthermore, the quality control of intracellular components by synchronously modulating the activity of different cellular mechanisms involved in the aforementioned pathologies. This, in turn, will guide the development of targeted therapies.
Nonsuicidal self‐injury and rumination: A meta‐analysis
Authors: Nagy Laura M. , Shanahan Mackenzie L. , Seaford Sara P.
Published: May 2022

Trait rumination is the tendency to overthink and focus on negative emotions and events and is related to a number of psychological disorders and maladaptive behaviors including nonsuicidal self‐injury (NSSI). The purpose of this study was to conduct a meta‐analysis of the relationship between trait rumination and NSSI behaviors. Results from 60 samples showed small effect sizes between trait rumination and NSSI engagement, NSSI frequency, and the number of methods used to self‐injure in cross‐sectional samples. Results from 13 samples showed small effect sizes between trait rumination and NSSI engagement and NSSI frequency in longitudinal samples. Moderator analyses indicated that this relationship is similar whether the type of rumination is depressive or not and is generally consistent across different ages, genders, and ethnicities. These results help clarify the role of trait rumination as a risk factor for NSSI.
Investigating the thermal oxidation behavior of Ti–6Al–7Nb alloy in dry air
Authors: Mohamed Lamiaa Z. , Abd Elmomen Sanaa S. , El‐Hadad Shimaa
Published: May 2022

The thermal oxidation behavior of a forged Ti–6Al–7Nb (Ti67) alloy was investigated in dry air conditions. The alloy specimens were oxidized for 50 h at different temperatures (650°C, 750°C, and 850°C) and the oxidation kinetics were analyzed. The microstructure of Ti67 after oxidation and the different phases and compounds were identified. A parabolic equation based on weight gain was used to define the oxidation rate. The parabolic rate constant increased from 1.10 × 10−8at 650°C to 2.10 × 10−8and 1.53 × 10−7g2/(cm4·h) at 750°C and 850°C, respectively. At 650°C, the oxidation behavior resumed the parabolic behavior until 40 h, a breakaway phenomenon. At 750°C, a linear behavior was observed in the periods of 20–50 h. This linear trend appeared also after 35–50 h at 850°C. The activation energy was found to be 238.4 kJ/mole. At the lowest oxidation temperature (650°C), a disconnected oxide layer was observed. These variations in the response of Ti67 alloy to the different thermal oxidation conditions are worthy of consideration when modifying the surfaces for biomedical applications.
Characterization of effective phytochemicals in traditional Chinese medicine by mass spectrometry
Authors: Chen Chung‐Yu , Li Yen‐Hsien , Li Zuguang , Lee Maw‐Rong
Published: May 2022

Traditional Chinese medicines (TCMs) have been widely used in clinical and healthcare applications around the world. The characterization of the phytochemical components in TCMs is very important for studying the therapeutic mechanism of TCMs. In the analysis process, sample preparation and instrument analysis are key steps to improve analysis performance and accuracy. In recent years, chromatography combined with mass spectrometry (MS) has been widely used for the separation and detection of trace components in complex TCM samples. This article reviews various sample preparation techniques and chromatography‐MS techniques, including the application of gas chromatography‐MS and liquid chromatography‐MS and other MS techniques in the characterization of phytochemicals in TCM materials and Chinese medicine products. This article also describes a new ambient ionization MS method for rapid and high‐throughput analysis of TCM components.
Analysentechnik: Nanopartikelanalyse erweitert
Authors: Schuldes Isabel , Fronk Vanessa , Unruh Tobias
Published: May 2022

Mit einer Kombination aus dynamischer Lichtstreuung, Röntgenkleinwinkelstreuung und elektrophoretischer Lichtstreuung lässt sich eine wässrige Dispersion von nanopartikulärem Coenzym Q10 charakterisieren.
Open Access wirkt
Authors: Zbikowski Frauke
Published: May 2022

Paper, die ohne Bezahlschranke zu lesen sind, verbessern den Wissenstransfer aus der Wissenschaft in die Gesellschaft.
Nonreductive homolytic scission of endoperoxide bond for activation of artemisinin: A parallel mechanism to Heterolytic cleavage
Authors: Sharma Shikha , Ali Md. Ehesan
Published: May 2022

Artemisinin is the most successful antimalarial drug against malaria caused by Plasmodium falciparum. Despite its tremendous success and popularity in malaria therapeutics, the molecular mechanism of artemisinin's activity is still elusive. The activation of artemisinin, i.e., cleavage of the endoperoxide bond at the infected cell that generates radical intermediates and the subsequent chemical rearrangements, plays a key role in the antimalarial activities. In this work, adopting state‐of‐the‐art computational techniques based on the spin‐constrained density functional theory (CDFT) along with ab initio thermodynamics, we have investigated the activation of artemisinin by two different pathways, homolytic and heterolytic cleavage. The homolytic scission of the endoperoxide bond is further followed by subsequent chemical reactions that propagate via biradical intermediates. Here we report that the free energy of activation of artemisinin associated with the homolytic cleavage is less (21.77 kcal/mol) than the heterolytic cleavage (23.64 kcal/mol). The nonreductive homolytic cleavage of the endoperoxide bond is thermodynamically slightly favorable. Thus, the latter could occur in parallel with the heterolytic activation of the artemisinin.
Tolerance and acceptance of hepatic venous pressure gradient measurement in cirrhosis (CHESS1904): An international multicenter study
Authors: Sun Jun‐Hui , Zhao He , Zhang Haijun , Li Lei , Örmeci Necati , Yu Zi‐Niu , Li Xun , Li Shuangxi , Yang Xujun , Wei Huaping , Zhu Xiaoliang , Zhang Zhengcong , Wang Yajin , Zhao Zhongwei , Mao Jianting , Wu Qiaohong , Sun Xiaole , Xiang Huiling , Jia Kefeng , Yang Chao , Wu Wei , Lin Xiuqing , Yao Haixin , Zuo Changzeng , Wang Jitao , Zhang Bo , Zhang Chunqing , Wu Xiaoling , Wang Guangchuan , Yao Shengjuan , Wang Ruihang , Zhou Li , Huan Hui , Tu Qingli , Pu Xue , Zhang Feng , Yin Qin , Zhang Linpeng , Guo Ying , Wang Jian , Kotani Kohei , Uchida‐Kobayashi Sawako , Kawada Norifumi , Zhu He , Li Li , Wang Wei , Zhang Guo , Yu Lei , Cui Xudong , Zhu Qingliang , Zhang Hailong , Hu Xiaoli , Ximenes Rafael O. , Gonçalves de Araújo Adriano , Gardenghi Giulliano , Zheng Yubao , Wu Zebin , Huang Mingsheng , Chen Xiaoyong , Wu Jun , Xie Feng , Bo Yang , Hu Shengjuan , Ma Linke , Li Xiao , Qi Xiaolong
Published: May 2022

Aim

To determine the tolerance and acceptance of hepatic venous pressure gradient (HVPG) measurements in patients with liver cirrhosis.

Methods

This prospective international multicenter study included 271 patients with cirrhosis who were scheduled to undergo HVPG measurement between October 2019 and June 2020. Data related to the tolerance and acceptance of HVPG measurements were collected using descriptive questionnaires.

Results

HVPG measurements were technically successful in all 271 patients, with 141 (52.0%) undergoing HVPG measurement alone. The complication rate was 0.4%. Postoperative pain was significantly lower than preoperative expected pain (p < 0.001) and intraoperative pain (p < 0.001), and intraoperative pain was also significantly lower than preoperative expected pain (p = 0.036). No, mild, moderate, severe, and intolerable discomfort scores were reported by 36.9%, 44.6%, 11.1%, 6.3%, and 0.4% of these patients, respectively, during HVPG measurement and by 54.6% 32.5%, 11.4%, 1.5%, and 0%, respectively, after HVPG measurement. Of these patients, 39.5% had little understanding and 10% had no understanding of the value of HVPG measurement, with 35.1% and 4.1% regarding HVPG measurements as being of little or no help, respectively. Most patients reported that they would definitely (15.5%), probably (46.9%), or possibly (29.9%) choose to undergo additional HVPG measurements again, and 62.7% regarded the cost of the procedure as acceptable.

Conclusion

HVPG measurement was safe and well‐tolerated in patients with cirrhosis, but patient education and communication are warranted to improve the acceptance of this procedure.
Plastic bronchitis secondary to bocavirus in a previously healthy 4‐year‐old with negative lymphatic evaluation
Authors: Leon Cynara , Tsukahara Katharine , Boggs Kaitlyn , Phinizy Pelton
Published: May 2022

This case of a child presenting with severe acute respiratory failure requiring extracorporeal membrane oxygenation due to plastic bronchitis demonstrates the possibility of developing this rare condition despite having no known underlying inflammatory or lymphatic issues. The normal lymphatic anatomy and flow in our patient several weeks after the acute illness suggests a transient lymphatic flow abnormality possibly driven by the acute lower respiratory tract infection with human bocavirus‐1 (HBoV1). As there are now four patients in the literature identified with Plastic bronchitis (PB) in the setting of HBoV1, it may be beneficial to include HBoV1 in the initial workup of patients with unknown etiology of PB. While routine use of MR lymphangiography is not warranted, we wonder if the procedure might help realize lymphatic flow abnormalities crucial to the pathophysiology if it can be performed safely in the acute setting. The heterogeneous population presents a challenge when studying PB, thus future studies are needed to elucidate the complex pathophysiology, guide management, and better understand prognosis.