bluuebunny/crossref_metadata_2025 huggingface dataset:
A simple method to calculate incident dose for the proximity effect correction
Authors: Xu Jian , Yang Shang , Wei Yayi
Published: February 2022

A simple method for correcting the proximity effect (PEC) is demonstrated. By modifying the discretized point spread function (PSF), the incident dose is expressed as a function of the ideal deposition energy density, the backscattering energy and the center energy fraction of the PSF matrix. The optimum incident dose can thus be solved iteratively. Then, the constraint to the iterative equation is discussed and the allowed value range of the center energy fraction in the discretized PSF is calculated under the different pattern densities. The correcting result is finally experimental verified. Results showed the line width deviation from the mean is decreased from the maximum of 0.01 μ. to that of below 0.003 μ.m after the PEC applied. The improved critical dimension (CD) uniformity indicating a uniformity energy distribution is achieved by this method.
NaOH ist nicht NaCl – ulzeröse Reaktion auf Natronlauge bei der Epikutantestung der Inhaltsstoffe einer Sonnenschutzcreme
Authors: Scherer Hofmeier Kathrin , Bircher Andreas J.
Published: February 2022

Bei der Epikutantestung mit patienteneigenem Material oder Einzelsubstanzen von komplexen Zubereitungen sind die Auswahl der Testsubstanzen und die Bedingungen, zu denen diese Substanzen getestet werden, von besonderer Wichtigkeit. Wir berichten über eine Patientin, bei der eine allergische Kontaktdermatitis nach Applikation einer Sonnencreme entstanden war. Im Rahmen der diagnostischen Epikutanteste wurden auch die einzelnen Inhaltstoffe der Sonnencreme, die vom Hersteller zur Verfügung gestellt worden waren, getestet. Dabei kam es zu einem folgenschweren Fehler, indem diese Inhaltsstoffe ohne ausreichende Überprüfung getestet wurden und u. a. Natronlauge appliziert wurde. Die entstandene Kolliquationsnekrose am Testort heilte erst innerhalb von ca. 2,5 Monaten spontan ab und gab Anlass für einen Haftpflichtfall. Die Aufarbeitung dieser Fehlleistung und die Konsequenzen, die in unserer Abteilung getroffen wurden, um dergleichen Probleme in Zukunft sicher vermeiden zu können, werden besprochen.
Teledermatologie: Fluch oder Segen?
Authors: Nikolakis Georgios , Baroud Sumer , Georgopoulos Ioannis , Appel Lena , Zouboulis Christos C.
Published: February 2022

Teledermatologische Dienste haben sich insbesondere während der COVID-19-Pandemie als Alternative zu „Echt“visiten verbreitet. Der Mangel an Dermatologen und die Möglichkeit einer präzisen Diagnose auch bei unterversorgten Regionen macht diese Alternative für alle Beteiligten besonders attraktiv. Trotzdem ist der Bedarf an Schulungen des Personals und der Anwender hoch. Ebenfalls können Implementierungs-, Instandhaltungs- und Wartungskosten der notwendigen Ausrüstung und die Heterogenität der unterschiedlichen Anbieter nachteilig für Patient und Arzt sein. In diesem Artikel werden wesentliche Vorteile und Nachteile der Teledermatologie zusammengefasst.
Intrastromale keratolimbale Epithelzysten: kongenital und postoperativ
Authors: Schoelles Kristina Joana , Auw-Hädrich Claudia , Maier Philip Christian , Reinhard Thomas
Published: February 2022

Zwei ungewöhnliche Fälle von intrastromalen keratolimbalen Epithelzysten werden präsentiert: Im 1. Fall handelt es sich um eine progredient wachsende kongenitale Zyste eines 9-jährigen
Jungen, im 2. Fall um eine rezidivierende postoperative Zyste einer 18-jährigen Patientin. Beide Patienten zeigten eine limbale Zyste, die sich als weißliche Masse in das Hornhautstroma
fortsetzte und bis zur optischen Achse reichte. Die Indikation zur Operation war im 1. Fall die Stabilisierung der Sehschärfe und im 2. Fall die Verbesserung des kosmetischen Aspekts. Im 1.
Fall wurde ein kleiner Teil der Zyste am Limbus eröffnet und das weißliche Material aus der Zyste herausgespült. Im 2. Fall wurde eine anteriore lamelläre Keratektomie über die gesamte Zyste
mit anschließender Mitomycin-C-Applikation durchgeführt. Die immunhistochemische Analyse zeigte in beiden Zysten Zytokeratin-19-positive Epithelzellen. Somit scheint eine Implantation von
Bindehautepithel in die Sklera für die Entstehung der jeweiligen keratolimbalen Zyste verantwortlich zu sein. Postoperativ wurden in beiden Fällen kosmetisch und funktionell
zufriedenstellende Ergebnisse erzielt mit einem Follow-up von 4 und 9 Monaten. Keratolimbale Zysten wurden in der Literatur bisher selten beschrieben. In den meisten Fällen handelt es sich
um eine konjunktivale Epithelimplantation nach einer Operation oder einem Trauma und nur sehr selten um eine angeborene Zyste. Nach einfacher Aspiration des Zysteninhalts wird oft ein
schnelles Rezidiv beobachtet, sodass eine teilweise oder möglichst vollständige Entfernung der vorderen Zystenwand empfohlen wird, wie in unseren Fällen erfolgt.
Roboterassistierte Chirurgie: Herausforderungen aus Sicht der Anästhesie
Authors: Lang Marika
Published: February 2022

Bei roboterassistierten Eingriffen gilt es vieles zu beachten, unter anderem müssen Zugänge, Verkabelung und Lagerung an die spezifischen OP-Gegebenheiten angepasst werden. Welche Besonderheiten und Herausforderungen diese OP-Technik für das Anästhesiepersonal bereithält, schildert unsere Autorin vom LMU Klinikum in München am Beispiel der radikalen Prostatektomie.
Synthetic Studies towards Pyrido[1,2-a]azepine Stemona Alkaloids
Authors: Morgenstern Martin , Mayer Camilla , Bach Thorsten , Pöthig Alexander
Published: February 2022

The carbon skeleton of the Stemona alkaloids stemokerrin and cochinchistemonine was assembled from three building blocks (a piperidine, a furan, and a tetronate). Key steps linking the fragments included a Stille cross-coupling (piperidine/furan) and an aldol-type addition of a tetronate. The furan served as a latent 1,4-difunctional compound which was converted into a γ-ketolactone by a type II photooxygenation. Attempts to construct the C12–C13 double bond of stemokerrin by a late-stage oxidation or by an elimination remained unsuccessful. The non-natural products dihydrostemokerrin and furostemokerrin were obtained instead.
4b-Aryltetrahydroindeno[1,2-a]indenes by Acid-Catalyzed Trans­annular Cyclization of Benzannulated Cyclooctene Alcohols
Authors: Ploypradith Poonsakdi , Songthammawat Poramate , Phumjan Tanawat , Ruchirawat Somsak
Published: February 2022

By starting from two simple building blocks, benzannulated cyclooctenones were obtained in three steps. Subsequent Grignard/aryl lithium addition to the ketone yielded the corresponding tertiary alcohols that underwent stereoselective acid-catalyzed transannular cyclization to provide a cis-fused 5/5 bicyclic indanylindane framework exclusively. Subsequent stereoselective nucleophilic addition to the indanyl cation by hydride, water, or electron-rich aromatics furnished the 4b-aryltetrahydroindano[1,2-a]indenes in good to excellent yields (up to 92%) in the trans-C9–C9a form in up to a >99:1 diastereomeric ratio.
Coinheritance of HbO Arab/β0-thalassemia with Severe Manifestation in Newborn
Authors: Kalai Miniar , Moumni Imen , Ouragini Houyem , Chaouechi Dorra , Boudriga Imen , Menif Samia
Published: February 2022

Objective In this study, we report a Tunisian newborn boy referred for neonatal hemolytic anemia with yellowish skin and enlarged spleen due to coinheritance of hemoglobin O (HbO) Arab and β-thalassemia.

Study Design Hematological parameters were collected using an automated blood cell counter. The amounts of Hb fractions were measured by capillary electrophoresis of Hb. Amplification and sequencing of the HBB gene were performed by Sanger's method.

Results Family study and genetic analysis revealed that the proband was a carrier of two hemoglobinopathies: HbO Arab and β0-thalassemia.

Conclusion The coexistence of these two pathologies complicated the general state of the newborn boy and led to a severe anemia at birth.

Key Points
Dressed behavior of the quasiparticles lifetime in the unitary limit of two unconventional superconductors
Authors: Contreras P. , Osorio Dianela , Beliayev E. Yu.
Published: February 2022

We compare the quasiparticle lifetime behavior in the unitary limit of two unconventional superconductors dressed by nonmagnetic impurity scattering to differentiate an anomalous functional behavior in its shape when the disorder concentration is changed in a triplet paired model with respect to the well behave singlet model. For singlet paired superconductors, the functional shape of the lifetime due to elastic scattering around the nodal regions in the reduced elastic scattering space, does not change with the disorder concentration, but for a triplet model with a tiny gap, an anomalous drop in shape is observed only when small values of disordering are added. We use a 2D tight-binding parametrization to study the reduced phase space of the first Brillouin zone, where the low-energy scattering is restricted to the nodal/quasinodal regions for two irreducible representations of the crystal lattice. A new class of Wigner probabilistic distribution functions is discussed for triplet superconductors.
Effective nonfrustrated model of the antiferromagnetic spin-1/2 ladder
Authors: Kryvchikov A. A.
Published: February 2022

The spin S = 1/2 Heisenberg model on the frustrated saw-tooth spin-chain formed by triangular structural elements is investigated. Using the numerical calculations of the finite scheme of zero-temperature density matrix renormalization group the dependence of the magnetization on the external field is obtained. The dependence of magnetization has several plateaus that correspond to the gaps of the energy spectrum. The effective non-frustrated model with a close energy spectrum away from phase transition points is constructed. The relations between the parameters of the effective model and the fields that correspond to plateaus of magnetization are obtained.
Landau theory of ferroelastic phase transitions: Application to martensitic phase transformations
Authors: Barabanov Oleksandr V. , Kosogor Anna
Published: February 2022

The peculiarities of two Landau-type theories of ferroelastic phase transitions have been analyzed. The predictions of both theories have been compared with well-known experimental data obtained for the shape memory alloys (SMAs) undergoing the first-order martensitic transformations (MTs). It has been shown that the predictions of the Landau–Devonshire theory, which disregards the third-order term in power expansion of Gibbs free energy, contradict the experimental data, while the results of the symmetry conforming Landau theory, which takes into account this term, are in agreement with experimental data. The impossibility of occurrence of the second-order MT is demonstrated starting from the thermodynamic definition of the second-order phase transition. It is argued that the stress–strain loops, obtained for SMAs, can imitate the stress-induced phase transition in the absence of such transition.
Low-temperature elasticity of amorphous polymers: Molecular model and rheological equation
Authors: Natsik V. D. , Rusakova H. V.
Published: February 2022

A molecular-kinetic model of the processes of highly elastic deformation of amorphous polymers is proposed and, on its basis, nonlinear rheological equations are obtained; these latter make it possible to describe these processes under changes of deformation conditions in a wide range: temperature, deforming stress, and strain rate. A connection of the nonlinear micromechanical model of a polymer with the classical macromechanical model of a standard linear body is established. The transitions between the structural-deformation states of a warm and frozen elastomer, as well as the effects of low-temperature deformation melting and quantum elasticity of an amorphous polymer, are discussed.
DQC: A Python program package for differentiable quantum chemistry
Authors: Kasim Muhammad F. , Lehtola Susi , Vinko Sam M.
Published: February 2022

Automatic differentiation represents a paradigm shift in scientific programming, where evaluating both functions and their derivatives is required for most applications. By removing the need to explicitly derive expressions for gradients, development times can be shortened and calculations can be simplified. For these reasons, automatic differentiation has fueled the rapid growth of a variety of sophisticated machine learning techniques over the past decade, but is now also increasingly showing its value to support ab initio simulations of quantum systems and enhance computational quantum chemistry. Here, we present an open-source differentiable quantum chemistry simulation code and explore applications facilitated by automatic differentiation: (1) calculating molecular perturbation properties, (2) reoptimizing a basis set for hydrocarbons, (3) checking the stability of self-consistent field wave functions, and (4) predicting molecular properties via alchemical perturbations.
Hydrodynamic analysis of propulsion process of zebrafish
Authors: Guo Chun-yu , Kuai Yun-fei , Han Yang , Xu Peng , Fan Yi-wei , Yu Chang-dong
Published: February 2022

This study analyzes the kinematic characteristics and flow field information of zebrafish in straight and steering acceleration states using time-resolved particle image velocimetry to explore how vortices are generated and controlled to achieve the desired motion. The important role of the high- and low-pressure zones in the wake of zebrafish wavy propulsion is also presented by quantifying the pressure field around the zebrafish. With their precise body and motion control, fish have a movement advantage that cannot be achieved by artificial machinery. Exploring the evolutionary process of the fish structure and surrounding flow field during zebrafish autonomous propulsion is helpful for understanding the active control means and propulsion mechanism of fish. Zebrafish were constrained in a transparent water tank, and laser and image acquisitions systems were used to capture their spontaneous movement behavior. The results show that the pull provided by the low-pressure area and the thrust provided by the high-pressure area together provide the forward power of the zebrafish. The findings from this analysis of the bending control and propulsion mechanism of the zebrafish body can facilitate the optimal design of underwater vehicle propulsion methods, such as the propulsion efficiency and maneuverability of a bionic propeller.
Thermodynamic effects on single cavitation bubble dynamics under various ambient temperature conditions
Authors: Phan Thanh-Hoang , Kadivar Ebrahim , Nguyen Van-Tu , el Moctar Ould , Park Warn-Gyu
Published: February 2022

Thermodynamic characteristics and their effects on single cavitation bubble dynamics are important to elucidate the physical behaviors of cavitation phenomena. In this study, experimental and numerical methods were utilized to explore the thermodynamic effects on single cavitation bubble dynamics under various ambient temperature conditions. A series of experiments was performed to generate a single cavitation bubble at ambient temperatures between 20 and 80 °C using a laser-induced method and a high-speed camera to observe the dynamic behaviors of bubbles. By increasing the ambient temperature, a nonspherical bubble shape with a jet flow at the bubble rebound stage was observed. Next, the numerical simulation results in terms of the bubble radius and bubble shape were validated with the corresponding experimental data. Generally, the results exhibited reasonable agreement, particularly at the later collapse and rebound stages. Critical hydrodynamic and thermodynamic mechanisms over multiple oscillation stages at different ambient temperatures were analyzed. The bubble behaviors and their intensities were numerically quantified with respect to the bubble radius, collapsing time, internal pressure, internal temperature, and phase transition rate parameters. The results showed that the maximum bubble radius, first minimum bubble radius, and collapsing time increased with an increase in the ambient temperature. Nevertheless, the peak values of the internal pressure and internal temperature decreased with an increase in the ambient temperature. Generally, the bubble collapsed less violently at high temperatures than at low temperatures.
Spectral dispersion of the linewidth enhancement factor and four wave mixing conversion efficiency of an InAs/GaAs multimode quantum dot laser
Authors: Ding Shihao , Dong Bozhang , Huang Heming , Bowers John , Grillot Frédéric
Published: February 2022

The spectral dependence of the linewidth enhancement factor (αH-factor) of a multimode InAs/GaAs quantum dot laser is analyzed. Amplified spontaneous and high-frequency modulation methods are used to experimentally retrieve the αH-factor of each longitudinal mode below and above the threshold. A dispersion of the αH-factor is unlocked across the entire optical spectrum, which is further illustrated in the context of four wave mixing experiments. The results show that the induced conversion efficiency is increased at lasing wavelengths where the linewidth enhancement is lower. These results highlight the importance of carefully monitoring the linewidth enhancement factor in quantum dot lasers especially for frequency combs and mode-locking applications in future optical communication systems.
Exact solution of polaritonic systems with arbitrary light and matter frequency-dependent losses
Authors: Cortese Erika , De Liberato Simone
Published: February 2022

In this paper, we perform the exact diagonalization of a light–matter strongly coupled system taking into account arbitrary losses via both energy dissipation in the optically active material and photon escape out of the resonator. This allows us to naturally treat the cases of couplings with structured reservoirs, which can strongly impact the polaritonic response via frequency-dependent losses or discrete-to-continuum strong coupling. We discuss the emergent gauge freedom of the resulting theory and provide analytical expressions for all the gauge-invariant observables in both the Power–Zienau–Woolley and the Coulomb representations. In order to exemplify the results, the theory is finally specialized to two specific cases. In the first one, both light and matter resonances are characterized by Lorentzian linewidths, and in the second one, a fixed absorption band is also present. The analytical expressions derived in this paper can be used to predict, fit, and interpret results from polaritonic experiments with arbitrary values of the light–matter coupling and with losses of arbitrary intensity and spectral shape in both the light and matter channels. A Matlab code implementing our results is provided.
Quantum chemistry-augmented neural networks for reactivity prediction: Performance, generalizability, and explainability
Authors: Stuyver Thijs , Coley Connor W.
Published: February 2022

There is a perceived dichotomy between structure-based and descriptor-based molecular representations used for predictive chemistry tasks. Here, we study the performance, generalizability, and explainability of the quantum mechanics-augmented graph neural network (ml-QM-GNN) architecture as applied to the prediction of regioselectivity (classification) and of activation energies (regression). In our hybrid QM-augmented model architecture, structure-based representations are first used to predict a set of atom- and bond-level reactivity descriptors derived from density functional theory calculations. These estimated reactivity descriptors are combined with the original structure-based representation to make the final reactivity prediction. We demonstrate that our model architecture leads to significant improvements over structure-based GNNs in not only overall accuracy but also in generalization to unseen compounds. Even when provided training sets of only a couple hundred labeled data points, the ml-QM-GNN outperforms other state-of-the-art structure-based architectures that have been applied to these tasks as well as descriptor-based (linear) regressions. As a primary contribution of this work, we demonstrate a bridge between data-driven predictions and conceptual frameworks commonly used to gain qualitative insights into reactivity phenomena, taking advantage of the fact that our models are grounded in (but not restricted to) QM descriptors. This effort results in a productive synergy between theory and data science, wherein QM-augmented models provide a data-driven confirmation of previous qualitative analyses, and these analyses in turn facilitate insights into the decision-making process occurring within ml-QM-GNNs.
Structures of glasses created by multiple kinetic arrests
Authors: Yu Junguang , Chen Zhenxuan , Teerakapibal Rattavut , Benmore Chris , Richert Ranko , Yu Lian
Published: February 2022

X-ray scattering has been used to characterize glassy itraconazole (ITZ) prepared by cooling at different rates. Faster cooling produces ITZ glasses with lower (or zero) smectic order with more sinusoidal density modulation, larger molecular spacing, and shorter lateral correlation between the rod-like molecules. We find that each glass is characterized by not one, but two fictive temperatures Tf (the temperature at which a chosen order parameter is frozen in the equilibrium liquid). The higher Tf is associated with the regularity of smectic layers and lateral packing, while the lower Tf with the molecular spacings between and within smectic layers. This indicates that different structural features are frozen on different timescales. The two timescales for ITZ correspond to its two relaxation modes observed by dielectric spectroscopy: the slower δ mode (end-over-end rotation) is associated with the freezing of the regularity of molecular packing and the faster α mode (rotation about the long axis) with the freezing of the spacing between molecules. Our finding suggests a way to selectively control the structural features of glasses.
A β-NMR study of the depth, temperature, and molecular-weight dependence of secondary dynamics in polystyrene: Entropy–enthalpy compensation and dynamic gradients near the free surface
Authors: McKenzie Iain , Fujimoto Derek , Karner Victoria L. , Li Ruohong , MacFarlane W. Andrew , McFadden Ryan M. L. , Morris Gerald D. , Pearson Matthew R. , Raegen Adam N. , Stachura Monika , Ticknor John O. , Forrest James A.
Published: February 2022

We investigated the depth, temperature, and molecular-weight (MW) dependence of the γ-relaxation in polystyrene glasses using implanted 8Li+ and β-detected nuclear magnetic resonance. Measurements were performed on thin films with MW ranging from 1.1 to 641 kg/mol. The temperature dependence of the average 8Li spin–lattice relaxation time (T1avg) was measured near the free surface and in the bulk. Spin–lattice relaxation is caused by phenyl ring flips, which involve transitions between local minima over free-energy barriers with enthalpic and entropic contributions. We used transition state theory to model the temperature dependence of the γ-relaxation, and hence T1avg. There is no clear correlation of the average entropy of activation (Δ‡S̄) and enthalpy of activation (Δ‡H̄) with MW, but there is a clear correlation between Δ‡S̄ and Δ‡H̄, i.e., entropy–enthalpy compensation. This results in the average Gibbs energy of activation, Δ‡Ḡ, being approximately independent of MW. Measurements of the temperature dependence of T1avg as a function of depth below the free surface indicate the inherent entropic barrier, i.e., the entropy of activation corresponding to Δ‡H̄ = 0, has an exponential dependence on the distance from the free surface before reaching the bulk value. This results in Δ‡Ḡ near the free surface being lower than the bulk. Combining these observations results in a model where the average fluctuation rate of the γ-relaxation has a “double-exponential” depth dependence. This model can explain the depth dependence of 1/T1avg in polystyrene films. The characteristic length of enhanced dynamics is ∼6 nm and approximately independent of MW near room temperature.
Broadband, efficient extraction of quantum light by a photonic device comprised of a metallic nano-ring and a gold back reflector
Authors: Haws Cori , Perez Edgar , Davanco Marcelo , Song Jin Dong , Srinivasan Kartik , Sapienza Luca
Published: February 2022

To implement quantum light sources based on quantum emitters in applications, it is desirable to improve the extraction efficiency of single photons. In particular, controlling the directionality and solid angle of the emission are key parameters, for instance, to couple single photons into optical fibers and send the information encoded in quantum light over long distances, for quantum communication applications. In addition, fundamental studies of the radiative behavior of quantum emitters, including studies of coherence and blinking, benefit from such improved photon collection. Quantum dots grown via Stranski–Krastanov technique have shown to be good candidates for bright, coherent, indistinguishable quantum light emission. However, one of the challenges associated with these quantum light sources arises from the fact that the emission wavelengths can vary from one emitter to the other. To this end, broadband light extractors that do not rely on high-quality factor optical cavities would be desirable, so that no tuning between the quantum dot emission wavelength and the resonator used to increase the light extraction is needed. Here, we show that metallic nano-rings combined with gold back reflectors increase the collection efficiency of single photons, and we study the statistics of this effect when quantum dots are spatially randomly distributed within the nano-rings. We show an average increase in the brightness of about a factor 7.5, when comparing emitters within and outside the nano-rings, in devices with a gold back reflector, and we measure count rates exceeding 7 × 106 photons per second and single photon purities as high as 85% ± 1%. These results are important steps toward the realization of scalable, broadband, easy to fabricate sources of quantum light for quantum communication applications.
Broadband and high-performance SnS2/FePS3/graphene van der Waals heterojunction photodetector
Authors: Shi Shun , Feng Ya , Li Bailing , Zhang Hongmei , Li Qiuqiu , Mo Zhangxun , Zhou Xinyun , Lu Zheyi , Dang Weiqi , Lin Xiaohui , Zhang Liqiang , Zhang Zucheng , Deng Wei , Li Jia , Zhong Mianzeng , Li Bo , Duan Xidong
Published: February 2022

Two-dimensional materials and their heterojunctions have received extensive attention in fundamental and applied research of photonics, electronics, and spintronics. Herein, we stacked SnS2, FePS3, and graphene (Gr) nanosheets into SnS2/FePS3/Gr van der Waals heterojunction, which exhibits broadband photoresponse from an ultraviolet region (405 nm) to an infrared region (850 nm) in atmosphere at room temperature. It was found that the dominated carrier of SnS2/FePS3 and SnS2/FePS3/Gr hererojunction was different in the electrical transport. The photoresponsivity of SnS2/FePS3/Gr heterojunction was about two orders of magnitude higher than that of SnS2 and FePS3 and SnS2/FePS3 heterojunction. The response time of SnS2/FePS3/Gr heterojunction was slightly shorter than that of SnS2/FePS3 heterojunction and two orders of magnitude shorter than that of SnS2 and FePS3 under the 450 nm laser. The high responsivity and short response time of SnS2/FePS3/Gr heterojunction should be attributed to the type II band alignment and short channel distance in the vertical direction where electrons and holes can be separated and transit fast. Our result offered an opportunity for realization of the high-performance and broadband photodetector.
Improved LED output power and external quantum efficiency using InGaN templates
Authors: Abdelhamid Mostafa , Routh Evyn L. , Hagar Brandon , Bedair S. M.
Published: February 2022

InGaN templates have recently attracted interest due to their ability to reduce strain in the quantum wells and to induce a red shift in the emission wavelength. For such technology to be competitive, it should outperform the traditional technology for LEDs grown on GaN substrates and offer improved output characteristics. InGaN based LEDs on InyGa1−yN templates with varying In-content of 8% ≤ y ≤ 12% are studied for the same emission wavelength. The electroluminescence, optical output power, and external quantum efficiency of the LEDs are investigated as a function of the In-content in the templates. LEDs on InGaN templates with In-content of 8–10% show better performance than LEDs grown on GaN. This enhancement is attributed to improved radiative recombination as a result of the reduced strain in the quantum wells. However, templates with In-content of ∼10.5% and ∼11% show inferior performance to the LEDs on GaN because the deterioration from the increased defects from the template is stronger than the improvement in the radiative recombination. It can be concluded that the InGaN templates with 8–10% offer a technology for LEDs that is outperforming the traditional GaN technology.
Revealing topological attributes of stiff plates by Dirac factorization of their 2D elastic wave equation
Authors: Deymier P. A. , Runge K.
Published: February 2022

Dirac factorization of the elastic wave equation of two-dimension stiff plates coupled to a rigid substrate reveals the possible topological properties of elastic waves in this system. These waves may possess spin-like degrees of freedom associated with a gapped band structure reminiscent of the spin Hall effect. In semi-infinite plates or strips with zero displacement edges, the Dirac-factored elastic wave equation shows the possibility of edge modes moving in opposite directions. The finite size of strips leads to overlap between edge modes consequently opening a gap in their spectrum eliminating the spin Hall-like effects. This Dirac factorization tells us what solutions of the elastic wave equation would be if we could break some symmetry. Dirac factorization does not break symmetry but simply exposes what topological properties of elastic waves may result from symmetry breaking structural or external perturbations.
The interplay of intra- and intermolecular errors in modeling conformational polymorphs
Authors: Beran Gregory J. O. , Wright Sarah E. , Greenwell Chandler , Cruz-Cabeza Aurora J.
Published: February 2022

Conformational polymorphs of organic molecular crystals represent a challenging test for quantum chemistry because they require careful balancing of the intra- and intermolecular interactions. This study examines 54 molecular conformations from 20 sets of conformational polymorphs, along with the relative lattice energies and 173 dimer interactions taken from six of the polymorph sets. These systems are studied with a variety of van der Waals-inclusive density functionals theory models; dispersion-corrected spin-component-scaled second-order Møller–Plesset perturbation theory (SCS-MP2D); and domain local pair natural orbital coupled cluster singles, doubles, and perturbative triples [DLPNO-CCSD(T)]. We investigate how delocalization error in conventional density functionals impacts monomer conformational energies, systematic errors in the intermolecular interactions, and the nature of error cancellation that occurs in the overall crystal. The density functionals B86bPBE-XDM, PBE-D4, PBE-MBD, PBE0-D4, and PBE0-MBD are found to exhibit sizable one-body and two-body errors vs DLPNO-CCSD(T) benchmarks, and the level of success in predicting the relative polymorph energies relies heavily on error cancellation between different types of intermolecular interactions or between intra- and intermolecular interactions. The SCS-MP2D and, to a lesser extent, ωB97M-V models exhibit smaller errors and rely less on error cancellation. Implications for crystal structure prediction of flexible compounds are discussed. Finally, the one-body and two-body DLPNO-CCSD(T) energies taken from these conformational polymorphs establish the CP1b and CP2b benchmark datasets that could be useful for testing quantum chemistry models in challenging real-world systems with complex interplay between intra- and intermolecular interactions, a number of which are significantly impacted by delocalization error.
Cassava wastewater can be safely used in the diet of feedlot lambs
Authors: Silva Paula A. , Pires Aureliano J. V. , Pina Douglas dos S. , Silva Robério R. , Santos Stefanie A. , Rodrigues Carlindo S. , Matos Luís H. A. , Eiras Carlos E. , Eiras Daiane Novais , Pereira Taiala C. de J. , de Carvalho Gleidson G. P.
Published: February 2022

Cassava wastewater is a potential environmental pollutant, which can become a serious issue when improperly disposed into water bodies due to the toxic effects of cyanogenic glycoside. However, the presence of organic nutrients (starch and soluble sugars, mainly) supports the possibility of using this by-product in animal feeding. This study was conducted to examine the intake, apparent digestibility, performance, and carcass characteristics of feedlot lambs fed diets with increasing concentrations of cassava wastewater. The experiment involved 35 uncastrated Santa Inês crossbred lambs at approximately 3 months old, with an average bodyweight of 20 kg (standard deviation ± 3.4 kg). Diets were formulated with hay of cassava shoots (roughage), a maize- and soybean-based concentrate (50:50 roughage-to-concentrate ratio), and cassava wastewater at 0, 12, 24, 36 or 48 g kg−1 of the total diet (as-fed basis). Dietary inclusion of cassava wastewater led to a linear decrease (P < 0.05) in the intakes of dry matter, organic matter, crude protein, neutral detergent fibre, non-fibrous carbohydrates, and total digestible nutrients. Ether extract intake was not significantly (P > 0.05) influenced by cassava wastewater inclusion in the diets. There was no influence of cassava wastewater on the apparent digestibility of the nutritional components or on any parameter related to animal performance or carcass characteristics. Depending on the quantity, the use of cassava wastewater does not affect the feedlot performance of lambs. Cassava wastewater can be included in feedlot finishing diets at a level of up to 48 g kg−1 (as-fed basis).
Antimicrobials added to the feed of weaned piglets at two ages improves the molecular expression of intestinal barrier proteins
Authors: Herrera Franco Victor H. , Pardo Carrasco Sandra C. , Parra Suescún Jaime E.
Published: February 2022

Context Weaning is the most critical period during a pig’s life, because it is a challenge with the change of environment, and the digestive system is not adapted to a solid diet at the time of weaning, favouring the appearance of intestinal disorders, infections and diarrhoea. Aims To quantify the gene abundance of intestinal barrier tight junction proteins in pigs fed diets added with antimicrobials and weaned at two ages. Methods A total of 150 pigs weaned at two ages (21 and 28 days) were distributed into groups: Control Diet 1 (D1-Ctrl) without antimicrobial; Diet 2 (D2-Ant): Ctrl with an antibiotic (bacitracin zinc); Diet 3 (D3-Prob): Ctrl with Bacillus subtilis PB6 (PTA-6737); Diet 4 (D4-OEO): Ctrl with oregano essential oil (OEO; Lippia origanoides); Diet 5 (D5-OA): Ctrl with a mixture of organic acids. On post-weaning Days 1, 15 and 30, pigs were euthanised, and a portion of the jejunum was removed to assess the gene abundance of the intestinal tight junction proteins (occludin-OCLN, zonula occludens-ZO-1 and claudins-CLAU) that were measured by qPCR. Key results The pigs fed the diet with the addition of D3-Prob and D4-OEO showed a higher abundance (P < 0.05) of intestinal barrier tight junction protein genes (CLAU-1, CLAU-4, OCLN, ZO-1) compared with the other diets. This abundance was observed in both piglets weaned early, at 21 days, and later at 28 days of age, where, in addition, a statistically significant difference between weaning ages (P < 0.05) was evidenced in favour of later weaning. Conclusions The addition of probiotics in the growth phase, together with weaning at 28 days of age, have a favourable impact on the intestinal digestive function of pigs, being able to influence morphometric and productive parameters, and serve as a basis for the analysis of molecular research related to intestinal health. Implications This research provides a basis for the use of natural nutritional alternatives, such as probiotic bacteria, as alternatives to growth-promoting antibiotics in the feed of growing pigs; in addition to encouraging a better adaptation of the piglet to the post-weaning phase, through late weaning.
Nucleophilic ability of 5-aminopyrazoles in the multicomponent synthesis of pyrazolodihydropyridines and pyrazolodihydropyrimidines
Authors: Varzaneh Mahdi Ahmadi , Memarian Hamid R. , Rudbari Hadi Amiri , Blacque Olivier
Published: February 2022

The nucleophilic ability of substituted 5-aminopyrazoles and the type of dicarbonyl component were investigated to synthesise various pyrazolodihydropyridines and pyrazolodihydropyrimidines. In this multicomponent reaction, two possible reaction mechanisms are proposed to elucidate the importance of the nucleophilic positions in the 5-aminopyrazole molecule leading to the different cyclocondensation products. The extent of the nucleophilicity of the C4-position (β-position of the enamine moiety), the lone pairs of the N1-atom and the NH2 group in the pyrazole molecule affect the reaction time and type of product formed. The acidity of the CH2 moiety of the β-dicarbonyl compound may affect the type of product formed. 1H and 13C NMR data and the X-ray crystal structure analysis support the experimental work and the formed product type.
Hiring women into senior leadership positions is associated with a reduction in gender stereotypes in organizational language
Authors: Lawson M. Asher , Martin Ashley E. , Huda Imrul , Matz Sandra C.
Published: February 2022

Significance

Gender inequality has been deemed the “greatest human rights challenge of our time” by the United Nations, and scholars across numerous disciplines agree that gender stereotypes represent a primary way by which this inequality is maintained. Yet changing stereotypes in a systemic, enduring way is extremely difficult. This is at least in part because stereotypes are transmitted and perpetuated through the language societies and organizations use to describe women, especially those in leadership roles. Here, we show that hiring women into leadership positions is associated with organizations characterizing women in more leadership-congruent, agentic ways. This shift mitigates a critical barrier to women’s progression in organizations and society: the incongruence of what it means to be a woman and a leader.
Rodents monitor their error in self-generated duration on a single trial basis
Authors: Kononowicz Tadeusz Władysław , van Wassenhove Virginie , Doyère Valérie
Published: February 2022

Significance

Evaluating the richness of representations mapping animals’ experience of time and space is a profound problem in neuroscience. Animals could base their behavior only on recent rewards, but they also could rely on more complex representations of their own behavior. When faced with a deadline, individuals seem to adjust their decision based on the overall knowledge of their performance. We evaluated whether rats monitor the timing of their own actions or adapt only based on recent rewards. Rats accurately reported the magnitude of their timing error in self-generated time intervals. The results show that rats track their own timing errors, deepening our understanding of error-monitoring abilities in rodents and the richness of their representation of elapsed time.
Kupyaphores are zinc homeostatic metallophores required for colonization of
Mycobacterium tuberculosis
Authors: Mehdiratta Kritee , Singh Shubham , Sharma Sachin , Bhosale Rashmi S. , Choudhury Rahul , Masal Dattatraya P. , Manocha Alzu , Dhamale Bhushan Dilip , Khan Naseem , Asokachandran Vivekanand , Sharma Pooja , Ikeh Melanie , Brown Amanda C. , Parish Tanya , Ojha Anil K. , Michael Joy Sarojini , Faruq Mohammed , Medigeshi Guruprasad R. , Mohanty Debasisa , Reddy D. Srinivasa , Natarajan Vivek T. , Kamat Siddhesh S. , Gokhale Rajesh S.
Published: February 2022

Significance

Mycobacterium tuberculosis
(
Mtb
) is the etiological agent of human tuberculosis (TB).
Mtb
can persist inside host macrophages by successfully adapting to intracellular conditions. Acquisition of balanced amounts of essential micronutrients is one such important process. Our studies have identified a metallophore produced on demand to restore
Mtb
zinc metabolic imbalance. These diacyl-diisonitrile lipopeptides, named kupyaphores, are specifically induced during infection and move in and out of cells to protect bacteria from host-mediated nutritional deprivation and intoxication. Furthermore, we identify an
Mtb
isonitrile hydratase homolog
,
expressed in low-zinc conditions, which probably facilitates zinc release from kupyaphores. Identification of this zinc acquisition strategy could provide opportunities in future to understand systemic zinc dysbiosis and associated manifestations in TB patients.
The importance of race, gender, and religion in naturalization adjudication in the United States
Authors: Ryo Emily , Humphrey Reed
Published: February 2022

Significance

This study examines group disparities in naturalization approvals by race/ethnicity, gender, and religion. We find that all else being equal, non-White applicants and Hispanic applicants are less likely to be approved than non-Hispanic White applicants, male applicants are less likely to be approved than female applicants, and applicants from Muslim-majority countries are less likely to be approved than applicants from other countries. In addition, we find that race/ethnicity, gender, and religion combine to produce a certain group hierarchy in terms of approval probabilities. For example, Blacks from Muslim-majority countries are much less likely to be approved than Whites from other countries. These findings underscore the continuing importance of race, gender, and religion in the making of US citizens.
Isotopic filtering reveals high sensitivity of planktic calcifiers to Paleocene–Eocene thermal maximum warming and acidification
Authors: Hupp Brittany N. , Kelly D. Clay , Williams John W.
Published: February 2022

Significance

Human-induced carbon emissions are causing global temperatures to rise and oceans to acidify. To understand how these rapid perturbations affect marine calcifying communities, we investigate a similar event in Earth’s geologic past, the Paleocene–Eocene thermal maximum (PETM). We introduce a method, isotopic filtering, to mitigate the time-averaging effects of sediment mixing on deep-sea microfossil records. Contrary to previous studies, we find that tropical planktic foraminifers in the central Pacific ocean were adversely affected by PETM conditions, as evidenced by a decrease in local diversity, extratropical migration, and impaired calcification. While these species survived the PETM through migration to cooler waters, it is unclear whether marine calcifiers can withstand the rapid changes our oceans are experiencing today.
The major genetic risk factor for severe COVID-19 is associated with protection against HIV
Authors: Zeberg Hugo
Published: February 2022

There are genetic risk factors that influence the outcome of COVID-19 [COVID-19 Host Genetics Initiative,
Nature
600, 472–477 (2021)]. The major genetic risk factor for severe COIVD-19 resides on chromosome 3 and is inherited from Neandertals [H. Zeberg, S. Pääbo,
Nature
587, 610–612 (2020)]. The risk-associated DNA segment modulates the expression of several chemokine receptors, among them CCR5, a coreceptor for HIV which is down-regulated in carriers of the COVID-19 risk haplotype. Here I show that carriers of the risk variant have an ∼27% lower risk of HIV infection.
Role of internal loop dynamics in antibiotic permeability of outer membrane porins
Authors: Vasan Archit Kumar , Haloi Nandan , Ulrich Rebecca Joy , Metcalf Mary Elizabeth , Wen Po-Chao , Metcalf William W. , Hergenrother Paul J. , Shukla Diwakar , Tajkhorshid Emad
Published: February 2022

Significance

Antibiotic resistance in Gram-negative pathogens has been identified as an urgent threat to human health by the World Health Organization. The major challenge with treating infections by these pathogens is developing antibiotics that can traverse the dense bacterial outer membrane (OM) formed by a mesh of lipopolysaccharides. Effective antibiotics permeate through OM porins, which have evolved for nutrient diffusion; however, the conformational states of these porins regulating permeation are still unclear. Here, we used molecular dynamics simulations, free energy calculations, Markov-state modeling, and whole-cell accumulation assays to provide mechanistic insight on how a porin shifts between open and closed states. We provide a mechanism of how Gram-negative bacteria confer resistance to antibiotics.
Kin selection for cooperation in natural bacterial populations
Authors: Belcher Laurence J. , Dewar Anna E. , Ghoul Melanie , West Stuart A.
Published: February 2022

Significance

Bacteria secrete many molecules outside the cell, where they provide benefits to other cells. One potential reason for producing these “public goods” is that they benefit closely related cells that share the gene for cooperation (kin selection). While many laboratory studies have supported this hypothesis, there is a lack of evidence that kin selection favors cooperation in natural populations. We examined bacterial genomes from the environment and used population genetics theory to analyze the DNA sequences. Our analyses suggest that public goods cooperation has indeed been favored by kin selection in natural populations.
Disentangling the last 1,000 years of human–environment interactions along the eastern side of the southern Andes (34–52°S lat.)
Authors: Nanavati William , Whitlock Cathy , de Porras Maria Eugenia , Gil Adolfo , Navarro Diego , Neme Gustavo
Published: February 2022

Significance

Understanding how people have shaped landscapes requires detailed information on past changes in climate, vegetation, fire, and land use. The environmental and human history of four sites along the eastern Andes of southern South America (34–52°S) shows the changing influence of people and climate on landscape development over the last millennia. Initially, burning by hunter-gatherers and climate variability shaped forest, shrubland, and grassland mosaics. Widespread alteration of fire regimes and vegetation ∼400 y ago is attributed to increased Native American pastoralism prior to extensive Euro-American settlement. Late-19th century ranching and logging led to broadscale changes in fire activity and vegetation across the region. These high-resolution, landscape-scale reconstructions reveal complex human–environment interactions that are often overlooked in regional-to-global syntheses.
Stress-responsive regulation of extracellular proteostasis
Authors: Mesgarzadeh Jaleh S. , Buxbaum Joel N. , Wiseman R. Luke
Published: February 2022

Genetic, environmental, and aging-related insults can promote the misfolding and subsequent aggregation of secreted proteins implicated in the pathogenesis of numerous diseases. This has led to considerable interest in understanding the molecular mechanisms responsible for regulating proteostasis in extracellular environments such as the blood and cerebrospinal fluid (CSF). Extracellular proteostasis is largely dictated by biological pathways comprising chaperones, folding enzymes, and degradation factors localized to the ER and extracellular space. These pathways limit the accumulation of nonnative, potentially aggregation-prone proteins in extracellular environments. Many reviews discuss the molecular mechanisms by which these pathways impact the conformational integrity of the secreted proteome. Here, we instead focus on describing the stress-responsive mechanisms responsible for adapting ER and extracellular proteostasis pathways to protect the secreted proteome from pathologic insults that challenge these environments. Further, we highlight new strategies to identify stress-responsive pathways involved in regulating extracellular proteostasis and describe the pathologic and therapeutic implications for these pathways in human disease.