bluuebunny/crossref_metadata_2025 huggingface dataset:
Association between dietary intake of branched-chain amino acids and sarcopenia and its components: a cross-sectional study
Authors: Ebrahimi-Mousavi Sara , Hashemi Rezvan , Bagheri Amir , Heshmat Ramin , Dorosty-Motlagh Ahmadreza , Esmaillzadeh Ahmad
Published: April 2022

There is no previous study that investigated the association between dietary intake of total and individual branched-chain amino acids (BCAAs) and odds of sarcopenia. The present study aimed to examine the association between dietary intake of BCAAs and sarcopenia and its components among Iranian adults. The data for this cross-sectional study was collected in 2011 among 300 older people (150 men and 150 female) with aged ≥ 55 years. We used a Block-format 117-item food frequency questionnaire (FFQ) to evaluate usual dietary intakes. BCAAs intake was calculated by summing up the amount of valine, leucine and isoleucine intake from all food items in the FFQ. The European Sarcopenia Working Group (EWGSOP) definition was used to determine sarcopenia and its components. Mean age of study participants was 66.8 years and 51% were female. Average intake of BCAAs was 12.8 ± 5.1 g/day. Prevalence of sarcopenia and its components was not significantly different across tertile categories of total and individual BCAAs intake. We found no significant association between total BCAAs intake and odds of sarcopenia (OR for comparison of extreme tertiles 0.48, 95% CI 0.19–1.19, P-trend = 0.10) and its components (For muscle mass 0.83, 95% CI 0.39–1.77, P-trend = 0.63; for hand grip strength 0.81, 95% CI 0.37–1.75, P-trend: 0.59; for gait speed 1.22, 95% CI 0.58–2.57, P-trend = 0.56). After adjusting for potential confounders, this non-significant relationship did not alter. In addition, we did not find any significant association between individual BCAAs intake and odds of sarcopenia or its components. We found no significant association between dietary intakes of BCAAs and sarcopenia in crude model (OR 0.60; 95% CI 0.29–1.26). After controlling for several potential confounders, the result remained insignificant (OR 0.48; 95% CI 0.19–1.19). In this cross-sectional study, no significant association was observed between dietary intakes of total and individual BCAAs and odds of sarcopenia and its components.
Selective etching of silicon nitride over silicon oxide using ClF3/H2 remote plasma
Authors: Lee Won Oh , Kim Ki Hyun , Kim Doo San , Ji You Jin , Kang Ji Eun , Tak Hyun Woo , Park Jin Woo , Song Han Dock , Kim Ki Seok , Cho Byeong Ok , Kim Young Lae , Yeom Geun Young
Published: April 2022

Precise and selective removal of silicon nitride (SiNx) over silicon oxide (SiOy) in a oxide/nitride stack is crucial for a current three dimensional NOT-AND type flash memory fabrication process. In this study, fast and selective isotropic etching of SiNx over SiOy has been investigated using a ClF3/H2 remote plasma in an inductively coupled plasma system. The SiNx etch rate over 80 nm/min with the etch selectivity (SiNx over SiOy) of ~ 130 was observed under a ClF3 remote plasma at a room temperature. Furthermore, the addition of H2 to the ClF3 resulted in an increase of etching selectivity over 200 while lowering the etch rate of both oxide and nitride due to the reduction of F radicals in the plasma. The time dependent-etch characteristics of ClF3, ClF3 & H2 remote plasma showed little loading effect during the etching of silicon nitride on oxide/nitride stack wafer with similar etch rate with that of blank nitride wafer.
Influence of infrastructure, ecology, and underpass-dimensions on multi-year use of Standard Gauge Railway underpasses by mammals in Tsavo, Kenya
Authors: Lala Fredrick , Chiyo Patrick I. , Omondi Patrick , Okita-Ouma Benson , Kanga Erustus , Koskei Michael , Tiller Lydia , Morris Aaron W. , Severud William J. , Bump Joseph K.
Published: April 2022

Rail and road infrastructure is essential for economic growth and development but can cause a gradual loss in biodiversity and degradation of ecosystem function and services. We assessed the influence of underpass dimensions, fencing, proximity to water and roads, Normalized Difference Vegetation Index (NDVI), presence of other species and livestock on underpass use by large and medium-sized mammals. Results revealed hyenas and leopards used the underpasses more than expected whereas giraffes and antelopes used the underpasses less than expected. Generalized linear mixed-effects models revealed that underpass height influenced use by wildlife, with several species preferring to use taller underpasses. Electric fencing increased underpass use by funneling species towards underpasses, except for elephants and black-backed jackal for which it reduced underpass passage. We also found that the use of underpasses by livestock reduced the probability of use by nearly 50% for wildlife species. Carnivore species were more likely to cross underpasses used by their prey. Buffalo, livestock, and hyenas used underpasses characterized by vegetation with higher NDVI and near water sources while baboons, dik-diks and antelope avoided underpasses with high NDVI. Our findings suggest a need for diverse and comprehensive approaches for mitigating the negative impacts of rail on African wildlife.
Mediators of differences by parental education in weight-related outcomes in childhood and adolescence in Norway
Authors: Mekonnen Teferi , Brantsæter Anne-Lise , Andersen Lene F. , Lien Nanna , Arah Onyebuchi A. , Gebremariam Mekdes K. , Papadopoulou Eleni
Published: April 2022

Studies exploring mediators of socioeconomic inequalities in excess weight gain in early-life and subsequent overweight/obesity (OW/OB) among youth are limited. Thus, this study examined the mediating role of prenatal and early postnatal factors and child energy balance-related behaviours (EBRB) in the effects of parental education on (i) excess weight gain from birth to 2 years and (ii) OW/OB at 5, 8 and 14 years. The Norwegian Mother, Father and Child Cohort Study was used to include participants at the ages of 2 (n = 59,597), 5 (n = 27,134), 8 (n = 28,285) and 14 (n = 11,278) years. Causal mediation analyses using the inverse odds weighting approach were conducted. Children of low-educated parents had a higher conditional excess weight gain at 2 years compared to children of high-educated parents (total effect, RRTE = 1.06; 95% CI 1.01, 1.10). The joint mediation effects of the prenatal and early postnatal factors explained most of the total effect of low education on conditional excess weight gain at 2 years. Children of low-educated parents had a higher risk of OW/OB at 5, 8 and 14 years compared to children of high-educated parents. The mediators jointly explained 63.7%, 67% and 88.9% of the total effect of parental education on OW/OB among 5, 8 and 14 year-old-children, respectively. Of the total mediated effects at 5, 8 and 14 years, the prenatal and early postnatal mediators explained 59.2%, 61.7% and 73.7%, whereas the child EBRB explained 10.3%, 15.8.0%% and 34.8%. The mediators included were found to have a considerable mediating effect in the associations explored, in particular the prenatal and early postnatal factors. If truly causal, the findings could indicate potential targets for interventions to tackle socioeconomic inequalities in OW/OB from birth to adolescence.
Structural and biochemical characterisation of the Providencia stuartii arginine decarboxylase shows distinct polymerisation and regulation
Authors: Jessop Matthew , Huard Karine , Desfosses Ambroise , Tetreau Guillaume , Carriel Diego , Bacia-Verloop Maria , Mas Caroline , Mas Philippe , Fraudeau Angélique , Colletier Jacques-Philippe , Gutsche Irina
Published: April 2022

Bacterial homologous lysine and arginine decarboxylases play major roles in the acid stress response, physiology, antibiotic resistance and virulence. The Escherichia coli enzymes are considered as their archetypes. Whereas acid stress triggers polymerisation of the E. coli lysine decarboxylase LdcI, such behaviour has not been observed for the arginine decarboxylase Adc. Here we show that the Adc from a multidrug-resistant human pathogen Providencia stuartii massively polymerises into filaments whose cryo-EM structure reveals pronounced differences between Adc and LdcI assembly mechanisms. While the structural determinants of Adc polymerisation are conserved only in certain Providencia and Burkholderia species, acid stress-induced polymerisation of LdcI appears general for enterobacteria. Analysis of the expression, activity and oligomerisation of the P. stuartii Adc further highlights the distinct properties of this unusual protein and lays a platform for future investigation of the role of supramolecular assembly in the superfamily or arginine and lysine decarboxylases.
Excess S-adenosylmethionine inhibits methylation via catabolism to adenine
Authors: Fukumoto Kazuki , Ito Kakeru , Saer Benjamin , Taylor George , Ye Shiqi , Yamano Mayu , Toriba Yuki , Hayes Andrew , Okamura Hitoshi , Fustin Jean-Michel
Published: April 2022

The global dietary supplement market is valued at over USD 100 billion. One popular dietary supplement, S-adenosylmethionine, is marketed to improve joints, liver health and emotional well-being in the US since 1999, and has been a prescription drug in Europe to treat depression and arthritis since 1975, but recent studies questioned its efficacy. In our body, S-adenosylmethionine is critical for the methylation of nucleic acids, proteins and many other targets. The marketing of SAM implies that more S-adenosylmethionine is better since it would stimulate methylations and improve health. Previously, we have shown that methylation reactions regulate biological rhythms in many organisms. Here, using biological rhythms to assess the effects of exogenous S-adenosylmethionine, we reveal that excess S-adenosylmethionine disrupts rhythms and, rather than promoting methylation, is catabolized to adenine and methylthioadenosine, toxic methylation inhibitors. These findings further our understanding of methyl metabolism and question the safety of S-adenosylmethionine as a supplement.
Growth of α-Sn on silicon by a reversed β-Sn to α-Sn phase transformation for quantum material integration
Authors: Liu Shang , Covian Alejandra Cuervo , Gardener Jules A. , Akey Austin , Levin Barnaby D. A. , Wang Xiaoxin , Liu Jifeng
Published: April 2022

α-Sn and SnGe alloys are attracting attention as a new family of topological quantum materials. However, bulk α-Sn is thermodynamically stable only below 13∘C. Moreover, scalable integration of α-Sn quantum materials and devices on silicon is hindered by their large lattice mismatch. Here, we grow compressively strained α-Sn doped with 2-4 at.% germanium on a native oxide layer on a silicon substrate at 300–500∘C. Growth is found to occur by a reversed β-Sn to α-Sn phase transformation without relying on epitaxy, with germanium-rich GeSn nanoclusters in the as-deposited material acting as seeds. The size of α-Sn microdots reaches up to 200 nm, which is approximately ten times larger than the upper size limit for α-Sn formation reported previously. Furthermore, the compressive strain makes it a candidate 3D topological Dirac semimetal with possible applications in spintronics. This process can be further optimized to achieve optically tunable SnGe quantum material and device integration on silicon.
Association of physical activity and sleep habits during pregnancy with autistic spectrum disorder in 3-year-old infants
Authors: Nakahara Kazushige , Michikawa Takehiro , Morokuma Seiichi , Hamada Norio , Ogawa Masanobu , Kato Kiyoko , Sanefuji Masafumi , Shibata Eiji , Tsuji Mayumi , Shimono Masayuki , Kawamoto Toshihiro , Ohga Shouichi , Kusuhara Koichi ,   the Japan Environment and Children’s Study Group, Kamijima Michihiro , Yamazaki Shin , Ohya Yukihiro , Kishi Reiko , Yaegashi Nobuo , Hashimoto Koichi , Mori Chisato , Ito Shuichi , Yamagata Zentaro , Inadera Hidekuni , Nakayama Takeo , Iso Hiroyasu , Shima Masayuki , Kurozawa Youichi , Suganuma Narufumi , Katoh Takahiko
Published: April 2022

Background:

We hypothesized that maternal lifestyle factors, such as physical activity and sleep habits, may be associated with autism spectrum disorder (ASD) in infants. This study aimed to investigate the association between maternal physical activity and sleep before and during pregnancy with infant ASD diagnosed by the age of 3 years.

Methods:

We used the data from the Japan Environment and Children’s Study between 2011 and 2014. The study included 103,060 pregnant women, among which, 69,969 women were analyzed. Participants were asked about their physical activity and sleep before and during pregnancy using questionnaires during pregnancy. Maternal physical activity was estimated using the international physical activity questionnaire. Based on the levels of physical activity before or during pregnancy, the participants were divided into five groups. Maternal sleep was analyzed based on sleep duration and bedtime. The outcome was diagnosis of ASD in 3-year-old infants.

Results:

In mothers with higher physical activity levels during pregnancy, the risk ratios (RR) for ASD in their 3-year-old infants were lower (RR = 0.61, 95% confidence interval (CI) = 0.42–0.90). In contrast, too short (<6 h) and too long (>10 h) sleep durations during pregnancy were associated with higher risk ratios for ASD than 7–8 h sleep duration (too short: RR = 1.87, 95% CI = 1.21–2.90; too long: RR = 1.56, 95% CI = 1.00–2.48). These associations were not observed before pregnancy.

Conclusion:

Maternal physical activity and sleep duration during pregnancy may be associated with ASD in infants.
Vitamin C enhances the ex vivo proliferation of porcine muscle stem cells for cultured meat production
Authors: Fang Jiahua , Li Mei , Zhang Guoqiang , Du Guocheng , Zhou Jingwen , Guan Xin , Chen Jian
Published: April 2022

VC stimulated porcine muscle stem cell proliferation by activating the PI3K/AKT/mTOR pathway through IGF-1 signaling.
Catalytic performance of mixed MxCo3−xO4 (M = Cr, Fe, Mn, Ni, Cu, Zn) spinels obtained by combustion synthesis for preferential carbon monoxide oxidation (CO-PROX): insights into the factors controlling catalyst selectivity and activity
Authors: Hudy Camillo , Długosz Olga , Gryboś Joanna , Zasada Filip , Krasowska Aneta , Janas Janusz , Sojka Zbigniew
Published: April 2022

A series of mixed cobalt spinel catalysts (MxCo3−xO4 (M = Cr, Fe, Mn, Ni, Cu, Zn)) was synthesized and tested in the CO-PROX reaction and in sole CO oxidation and H2 oxidation as references.
Correction: Gut microbiota can utilize prebiotic birch glucuronoxylan in production of short-chain fatty acids in rats
Authors: Kynkäänniemi Emma , Lahtinen Maarit H. , Jian Ching , Salonen Anne , Hatanpää Timo , Mikkonen Kirsi S. , Pajari Anne-Maria
Published: April 2022

Correction for ‘Gut microbiota can utilize prebiotic birch glucuronoxylan in production of short-chain fatty acids in rats’ by Emma Kynkäänniemi et al., Food Funct., 2022, 13, 3746–3759, DOI: 10.1039/D1FO03922A.
Electrocatalytic water oxidation from a mixed linker MOF based on NU-1000 with an integrated ruthenium-based metallo-linker
Authors: Howe Andrew , Liseev Timofey , Gil-Sepulcre Marcos , Gimbert-Suriñach Carolina , Benet-Buchholz Jordi , Llobet Antoni , Ott Sascha
Published: April 2022

Pyrene-mediated hole hopping transport to ruthenium-based catalysts in the MOF crystal interior results in active water oxidation electrocatalysts.
Morpholine substituted quinazoline derivatives as anticancer agents against MCF-7, A549 and SHSY-5Y cancer cell lines and mechanistic studies
Authors: Dwivedi Ashish Ranjan , Kumar Vijay , Prashar Vikash , Verma Akash , Kumar Naveen , Parkash Jyoti , Kumar Vinod
Published: April 2022

A series of morpholine substituted quinazoline derivatives have been synthesized and evaluated for cytotoxic potential against A549, MCF-7 and SHSY-5Y cancer cell lines.
Template synthesis of dual-functional porous MoS2nanoparticles with photothermal conversion and catalytic properties
Authors: Pan Xuefeng , Sarhan Radwan M. , Kochovski Zdravko , Chen Guosong , Taubert Andreas , Mei Shilin , Lu Yan
Published: April 2022

This contribution offers new opportunities for using porous MoS2particles as promising candidates for photothermal-assisted catalysis.
Molecular quantum interference effects on thermopower in hybrid 2-dimensional monolayers
Authors: Ghomian Taher , Kizilkaya Orhan , Domulevicz Lucas Kyle , Hihath Joshua
Published: April 2022

Quantum interference effects in single-molecule devices can significantly enhance the thermoelectric properties of these devices.
Orthogonal redox and optical stimuli can induce independent responses for catechol-chitosan films
Authors: Zhao Zhiling , Kim Eunkyoung , Chen Chen-Yu , Rzasa John R. , Zhang Qian , Li Jinyang , Tao Yang , Bentley William E. , Lumb Jean-Philip , Kohler Bern , Payne Gregory F.
Published: April 2022

Top-down measurements of catechol films show orthogonal energy flow via redox and optical modalities. These molecular electronic properties enable communication through both short-range redox modalities and long-range electromagnetic modalities.
Catalytic electron drives host–guest recognition
Authors: Owatari Yoshihiro , Iseki Shuta , Ogata Daiji , Yuasa Junpei
Published: April 2022

The reactants of AQH–CH2CN are converted into AQ and CH3CN in sustainable electrocatalytic chain reactions, successfully achieving catalytic electron-triggered charge-transfer (CT) complex formation.
Z-equilibrium in random bi-matrix games: Definition and computation
Authors: Achemine Farida , Larbani Moussa
Published: April 2022

This paper deals with bi-matrix games with random payoffs. Using probability tools, we propose a solution based on the concept of Z-equilibrium. Then, we give sufficient conditions of its existence. Further, the problem of computation of this solution is transformed into the determination of Pareto optimal solutions of a deterministic bi-criteria minimization problem. Finally, we provide illustrative numerical examples.
First Report of Neousicoccum luteum as the Causal Agent of Canker and Die-Back of Cupressus sempervirens
Authors: Fernandes L. , Paiva D. , Roxo I. , Trovão J. , Bragança H. , Portugal A.
Published: April 2022

The Mediterranean cypress (Cupressus sempervirens) is a species native to the eastern Mediterranean region, with many uses and properties. The Botryosphaeriaceae fungal family and in particular Neofusicoccum luteum are known for being both primary pathogens and opportunists, mainly on woody hosts such as conifers. This species was first reported in Portugal in 2012 on several coniferous hosts, including C. sempervirens. However, no report of N. luteum causing disease in this host has been reported either in Portugal or in any other country. In an attempt to understand the underlying causes of dieback of one C. sempervirens tree in the municipality of Aveiro (Portugal), we conducted a multi analytical study based on fungal isolation and identification. Fungal isolations were made from unhealthy plant material, resulting in the N. luteum identification. Moreover, Koch's postulates were carried out, leading to the development of lesions at the inoculation spots in the tested plants. Further re-isolation attempts from lesion areas lead to the confirmation of the presence of N. luteum. Our results point that N. luteum was the causal agent of disease on the sampled tree, marking this as the first report of N. luteum causing dieback in C. sempervirens. These results can be important in future diagnosis of this disease in this host, as well as be the kick-start for prevention regarding the aforementioned fungus.
Was wissen Sie über … Pflanzen?
Authors: Schmid Eva C.
Published: April 2022

Liebe Leser, testen Sie Ihr Wissen und frischen Sie Ihre Kenntnisse auf. Bitte kreuzen Sie jeweils eine Antwort an. Viel Spaß beim Beantworten wünscht Ihnen HP Eva C. Schmid!
Rhythmusgeber aus dem Takt
Authors: von Löwensprung Natalie Rosenhauer
Published: April 2022

Aus anthroposophischer Sicht vermittelt das Herz als wesentlicher Teil des Rhythmischen Systems zwischen dem Nerven-Sinnes-System (oberer Mensch) und dem Stoffwechsel-Gliedmaßen-System (unterer Mensch). Zu den bewährtesten anthroposophischen Pflanzenmitteln bei funktionellen Herzbeschwerden zählen Crataegus und Melissa mit ihrer herzstärkenden beziehungsweise -ausgleichenden Wirkung. Im vorgestellten Fall wird ein Patient mit Stresssymptomatik und Herzpalpitationen mithilfe von Crataegus, Melissa, Aurum, Biografiearbeit und Bewegung wieder weitgehend beschwerdefrei.
Copper-Catalyzed C–S Formation for the Synthesis of Benzyl Phenyl Sulfides from Dithiocarbamates
Authors: Dong Zhi-Bing , Zhou Yu , Yang Cheng-Li , Ye Lei
Published: April 2022

An odorless and efficient protocol for the synthesis of benzyl phenyl sulfides is reported. Starting from environmentally friendly phenyl dithiocarbamates and commercially available benzyl halides as starting materials, the target compounds (benzyl phenyl sulfides) could be obtained smoothly and easily by using copper salt as catalyst and Cs2CO3 as base. This method features ligand/additive-free, the use of readily available starting materials, inexpensive catalysts, and good substrate suitability, illustrating its potentially synthetic value for the convenient preparation of some biologically active molecules.
3-Trifluoromethylbenzyne: Precise Orientation in Cycloaddition Reaction Enabled Regioselective Synthesis of Trifluoromethylated Triptycenes
Authors: Iwata Takayuki , Shindo Mitsuru , Hyodo Mizuki , Fujiwara Takumi , Kawano Ryusei , Kuhn Leah , Alabugin Igor V.
Published: April 2022

The first regioselective addition reactions to 3-trifluoromethylbenzyne are reported. Triple cycloaddition of ynolates to the benzyne provided 1,8,13-tris(trifluoromethyl)triptycenes with high regioselectivity. 1-Trifluoromethyltriptycenes were regioselectively obtained by the Diels–Alder reaction of anthranoxides with the benzyne. These selectivities are attributed to the electron-acceptor nature of the trifluoromethyl group on the benzyne.
Developments in 1D micelle nanostructures points to new applications in medicine
Authors: Liebendorfer Adam
Published: April 2022

Recent work to better understand the fundamental processes that lead to self-assembling particles poses new directions for drug delivery and diagnostics.
Analytic continuation of stochastic mechanics
Authors: Kuipers Folkert
Published: April 2022

We study a (relativistic) Wiener process on a complexified (pseudo-)Riemannian manifold. Using Nelson’s stochastic quantization procedure, we derive three equivalent descriptions for this problem. If the process has a purely real quadratic variation, we obtain the one-sided Wiener process that is encountered in the theory of Brownian motion. In this case, the result coincides with the Feyman–Kac formula. On the other hand, for a purely imaginary quadratic variation, we obtain the two-sided Wiener process that is encountered in stochastic mechanics, which provides a stochastic description of a quantum particle on a curved spacetime.
Interfacial thermal transport between graphene and diamane
Authors: Hong Yang , Kretchmer Joshua S.
Published: April 2022

Similar to graphene, diamane is a single layer of diamond that has been investigated in recent years due to its peculiar mechanical, thermal, and electronic properties. Motivated by earlier work that showed an exceptionally high intra-plane thermal conductivity in diamane, in this work, we investigate the interfacial thermal resistance (R) between graphene and diamane using non-equilibrium classical molecular dynamics simulations. The calculated R for a pristine graphene and AB-stacked diamane at room temperature is 1.89 × 10−7 K m2/W, which is comparable to other common graphene/semi-conductor bilayers. These results are understood in terms of the overlap of the phonon density of states between the graphene and diamane layers. We further explore the impact of stacking pattern, system temperature, coupling strength, in-plane tensile strain, and hydrogenation ratio on R. Intriguingly, we find that unlike single layer diamane, where the intra-plane thermal conductively is reduced by ∼50% under 5% strain, the inter-plane thermal conductance of the graphene–diamane bilayer is enhanced by ∼50% under 8% strain. The difference is caused by the opposite behavior between the inter- and intra-layer conductances as phonon relaxation time is decreased. The high intra-plane thermal conductivity and low inter-plane thermal resistance shows the high potential of using graphene–diamane heterostructures in electronic applications.
Sudden collapse of a pressure profile generated by off-axis heating in a linear magnetized plasma
Authors: Van Compernolle B. , Poulos M. J. , Morales G. J.
Published: April 2022

The features of an unexpected, large event that arises spontaneously during a basic heat transport experiment are presented. It consists of the sudden collapse of the radial plasma pressure profile, akin to disruption events observed in toroidal magnetic confinement devices. The experiment is performed on the Large Plasma Device at the University of California, Los Angeles (UCLA). It uses a LaB6 thermionic emitter of annular shape to induce off-axis heating of a cold, afterglow plasma, in a linear magnetic geometry. The temporal evolution consists of three regimes. During an early, quiescent period, classical heat transport along and across the magnetic field arises from Coulomb collisions. After significant pressure gradients develop, drift-Alfvén waves become unstable. Upon reaching large amplitude, they trigger avalanche events that flatten the outer part of the heated region, which, in turn, quenches the instability. Due to the sustained heating, the pressure profile rebuilds and the process repeats, leading to a relatively long, second regime that displays multiple avalanches, but suddenly, the annular pressure profile is observed to collapse. After this collapse, the system enters a third regime with large fluctuations. Before the collapse, a rapid, runaway heating environment arises whose time evolution exhibits a self-similar dependence on the applied voltage. The time evolution, morphology, and scaling of the collapse event are presented, and an examination is made of the underlying mechanisms.
Molecular vibrational imaging at nanoscale
Authors: Choi Boogeon , Jeong Gyouil , Shin Hyun-Hang , Kim Zee Hwan
Published: April 2022

The demand to visualize the spatial distribution of chemical species based on vibrational spectra is rapidly increasing. Driven by such a need, various Raman and infrared spectro-microscopies with a nanometric spatial resolution have been developed over the last two decades. Despite rapid progress, a large gap still exists between the general needs and what these techniques can achieve. This Perspective highlights the key challenges and recent breakthroughs of the two vibrational nano-imaging techniques, scattering-type scanning near-field optical microscopy and tip-enhanced Raman scattering.
Migration of an active colloidal cell in inhomogeneous environments
Authors: Li Longfei , Li Wenjian , Chen Ke , Zheng Ning , Yang Mingcheng
Published: April 2022

Living cells on a substrate with mechanical inhomogeneities often migrate along or against the mechanical gradient, i.e., mechanotaxis, which inspires us to ask how biomimetic cells without biochemical signaling processes respond to environmental inhomogeneity. Here, we perform computer simulations to study the migration of a 2D active colloidal cell (ACC), which consists of active particles enclosed by a passive vesicle, in a heterogeneous environment composed of two adjoining uniform regions with different attributes (influencing the persistent length of the active particle). We find that the ACC can migrate unidirectionally across the interface separating the heterogeneous region and behave tactically. Interestingly, the tactic motion of the ACC is qualitatively different from that of the constituent active particles themselves. In addition, the ACC may also experience a directed drift along the interface of the heterogeneous environment. The tactic behavior of the ACC can be explained by analyzing the pressure distribution on the cell membrane exerted by the enclosed active particles. The findings provide insights into understanding the taxis of biological cells and designing biomimetic cells with environment-sensitive capabilities.
A miniature fiber-optic microphone based on plano-concave micro-interferometer
Authors: Han Chunyang , Ding Hui , Li Baojin , Shi Lei , Xu Haodong
Published: April 2022

The sensitive detection of sound waves is essential for a variety of applications. In this work, we propose a miniature diaphragm-free fiber-optic microphone based on a plano-concave optical micro-interferometer. A solid plano-concave micro-interferometer is formed at the end of a cleaved fiber by depositing a tiny volume of liquefied glass. Sound wave induced periodic variation of pressure can significantly modify the refractive index of the plano-concave glass due to the elasto-optic effect, and then, the phase difference between two interferometric beams will be remarkably changed accordingly. The interferometer finally converts the fluctuation of the phase difference into the change in the output optical power. Consequently, the sound wave can be demodulated by detecting the output power of the microphone. The experimental results show that the proposed microphone has the ability to detect sound waves in the whole audible range and almost omnidirectional. The noise-limited minimum detectable sound pressure is around 12 µPa/Hz. In addition, the human voice detection test shows that the performance of our microphone is competitive with the most advanced commercial device. The structure is stable without any movable mechanical parts, and the size is as small as 0.25 mm, which makes the proposed microphone an attractive alternative to the conventional one for sound wave detection.
Weakly nonlinear shape oscillations of a Newtonian drop
Authors: Zrnić D. , Berglez P. , Brenn G.
Published: April 2022

Nonlinear axisymmetric shape oscillations of a Newtonian drop in a vacuum are investigated theoretically, for fundamental interest and for their relevance in transport processes across the drop surface. The weakly nonlinear analysis is carried out for, but not limited to, the modes of initial drop deformation up to m = 4. The drop Ohnesorge number covers the range between 0.01 and 1. The weakly nonlinear approach, which is carried to third order, accounts for the coupling of different oscillation modes. With increasing surface deformation, the oscillations develop an asymmetry of the times during one period the drop spends in different states of deformation, a frequency decrease below the linear value, and quasi-periodicity of the motion. In contrast to the inviscid case [D. Zrnić and G. Brenn, “Weakly nonlinear shape oscillations of inviscid drops,” J. Fluid Mech. 923, A9 (2021)], the present analysis reveals the frequency decrease and the quasi-periodicity already in the second-order approximation. The results are positively validated against relevant literature. The theory quantifies the effects of viscosity, measured by the drop Ohnesorge number, dampening the nonlinear behavior and enhancing the coupling of different oscillation modes [E. Becker et al., “Nonlinear dynamics of viscous droplets,” J. Fluid Mech. 258, 191 (1994)]. The present theory reveals the quasi-periodicity of nonlinear viscous drop shape oscillations at strong deformation. The resultant drop motion, starting from a higher-order mode of initial deformation, for which the drop exhibits aperiodic linear behavior, may turn into damped oscillatory with ongoing time due to the coupling to lower-order modes.
The mechanism of surface-seal splash during water entry
Authors: Wang Yufei , Wang Zhiying , Du Yan , Wang Jingzhu , Wang Yiwei , Huang Chenguang
Published: April 2022

When a solid body impacts quiescent water at a certain velocity, the resultant “surface-seal splash” deforms and closes above the free surface. This study investigates the dynamics of the surface-seal splash by using a high-speed camera and particle image velocimetry (PIV) measurements. Based on PIV, an analytical model is developed to understand the mechanics of the surface-seal splash. The results indicate that the theoretical splash shapes are consistent with the experimental results. In addition, the effects of gravity, drag, surface tension, and aerodynamic pressure on the dynamics of surface-seal splash are also assessed, and the results indicate that the aerodynamic pressure plays a dominant role in the formation of the surface-seal splash.
Vortex dynamics of tandem bare and spiral finned cylinders in cross-flow and their susceptibility to acoustic resonance excitation
Authors: Alziadeh M. , Mohany A.
Published: April 2022

The vortex dynamics of tandem bare and spiral finned cylinders in the cross flow are experimentally investigated at a spacing ratio of L/Deq=2. Three different fin pitch-to-root diameter ratios (p/Dr) are considered. For high p/Dr, the fins on the downstream cylinder inhibit the shear layer growth and flapping in the cylinders' gap. Shear layer flapping is only observed for finned cylinders with the lowest p/Dr. Moreover, the gap shear layers enclose the downstream cylinder, enabling the formation of large vortex cores. The flow characteristics of finned cylinders are found to be independent of the Reynolds number with higher values of the Strouhal number due to an enlarged vortex formation length. For tandem bare cylinders, acoustic resonance excitation is triggered by two sources: (1) shear layer flapping in the cylinders' gap and (2) vortex shedding in the wake of the cylinders. All the tandem finned cylinders were able to excite acoustic resonance by the latter source. However, only tandem finned cylinders with the lowest p/Dr were capable of exciting resonance by the former source. During this excitation, weaker shear layer flapping resulted in the formation of smaller vortex cores in the finned cylinders' gap. During the second resonance, single vortex pairs formed per cycle in the wake of the downstream finned cylinder, whereas two vortex pairs formed per cycle in the wake of the downstream bare cylinder. This work shows that the addition of fins changes the impinging flow mechanism and the flow topology, which cannot be captured using the equivalent diameter approach.
Characteristics of enhanced mixing induced by plate jet actuation in supersonic flow
Authors: Zhang Dongdong , Cui Peng , Tan Jianguo , Yao Xiao , Liu Yao , Song Jie
Published: April 2022

The fast and efficient mixing of fuel and oxidizers under supersonic conditions is of great importance for improving the performance of scramjet engines. The mixing process in the inner flow of a scramjet combustor is heavily inhibited by compressibility effects. In this paper, the novel strategy of plate jet actuation is proposed, and its effects on mixing augmentation are analyzed by employing numerical programs developed in-house. The fine vortex structures induced by the plate jet actuation are well captured, and the dynamic behaviors of newly observed T-shaped structures are analyzed in detail. It is found that in plate jet actuation flow, Kelvin–Helmholtz (K–H) vortices induced by K–H instability coexist with T-shaped structures induced by jet actuation instability. The interaction of adjacent T-shaped structures leads to the distortion and breakup of large-scale structures, which can obviously improve the interfaces of upper and lower streams. The distribution of the turbulence intensity along the streamwise direction suggests that with the introduction of plate jet actuation, more intense fluctuations occur in the flow. The growth process of mixing layer thickness indicates that with plate jet actuation, a sharp increase in mixing thickness can be achieved in the near flow field. The results of structural topology analysis show that upper plate jet actuation can produce structures with larger sizes, and the distortion and penetration process of these structures can entrain more upper and lower streams into the mixing region. It is suggested that the present proposed strategy is a good candidate for mixing enhancement with the application of scramjet combustors.
Generating 77 T using a portable pulse magnet for single-shot quantum beam experiments
Authors: Ikeda Akihiko , Matsuda Yasuhiro H. , Zhou Xuguang , Peng Shiyue , Ishii Yuto , Yajima Takeshi , Kubota Yuya , Inoue Ichiro , Inubushi Yuichi , Tono Kensuke , Yabashi Makina
Published: April 2022

We devised a portable system that generates pulsed high magnetic fields up to 77 T with 3 μs duration. The system employs the single turn coil method, a destructive way of field generation. The system consists of a capacitor of 10.4 μF, a 30 kV charger, a mono air-gap switch, a triggering system, and a magnet clamp, which weighs less than 1.0 tons in total and is transportable. The system offers opportunities for single-shot experiments at ultrahigh magnetic fields in combinations with novel quantum beams. The single-shot x-ray diffraction experiment using a x-ray free-electron laser at 65 T is presented. We comment on the possible update of the system for the generation of 100 T.
Atomic shell structure from Born probabilities: Comparison to other shell descriptors and persistence in molecules
Authors: Menéndez-Herrero María , Munárriz Julen , Francisco Evelio , Martín Pendás Ángel
Published: April 2022

Real space chemical bonding descriptors, such as the electron localization function or the Laplacian of the electron density, have been widely used in electronic structure theory thanks to their power to provide chemically intuitive spatial images of bonded and non-bonded interactions. This capacity stems from their ability to display the shell structure of atoms and its distortion upon molecular formation. Here, we examine the spatial position of the N electrons of an atom at the maximum of the square of the wavefunction, the so-called Born maximum, as a shell structure descriptor for ground state atoms with Z = 1–36, comparing it to other available indices. The maximization is performed with the help of variational quantum Monte Carlo calculations. We show that many electron effects (mainly Pauli driven) are non-negligible, that Born shells are closer to the nucleus than any other of the examined descriptors, and that these shells are very well preserved in simple molecules.
Meta-analysis of transcriptomic responses to cold stress in plants
Authors: Vergata Chiara , Yousefi Sanaz , Buti Matteo , Vestrucci Federica , Gholami Mansour , Sarikhani Hassan , Salami Seyed Alireza , Martinelli Federico
Published: April 2022

Transcriptomic analyses are needful tools to gain insight into the molecular mechanisms underlying plant responses to abiotic stresses. The aim of this study was to identify key genes differentially regulated in response to chilling stress in various plant species with different levels of tolerance to low temperatures. A meta-analysis was performed using the RNA-Seq data of published studies whose experimental conditions were comparable. The results confirmed the importance of ethylene in the hormonal cross-talk modulating the defensive responses against chilling stress, especially in sensitive species. The transcriptomic activity of five Ethylene Response Factors genes and a REDOX Responsive Transcription Factor 1 involved in hormone-related pathways belonging to ethylene metabolism and signal transduction were induced. Transcription activity of two genes encoding for heat shock factors was enhanced, together with various genes associated with developmental processes. Several transcription factor families showed to be commonly induced between different plant species. Protein–protein interaction networks highlighted the role of the photosystems I and II, as well as genes encoding for HSF and WRKY transcription factors. A model of gene regulatory network underlying plant responses to chilling stress was developed, allowing the delivery of new candidate genes for genetic improvement of crops towards low temperatures tolerance.
Transcriptome and metabolite profiling to identify genes associated with rhizome lignification and the function of ZoCSE in ginger (
Authors: Zhang Xian , Ran Dongsheng , Wu Peiyin , Cao Zhengyan , Xu Feng , Xia Ning , Gao Hongmei , Jiang Ying , Yang Cheng , He Na , Tang Ning , Chen Zexiong
Published: April 2022

Ginger (Zingiber officinale Roscoe) is an important spice crop in China, and fresh ginger rhizomes are consumed as vegetable in Sichuan and Chongqing. However, tissue lignification accelerates with rhizome maturation, resulting in the loss of edible quality. To understand the molecular mechanisms of texture modification during rhizome development, we investigated lignin accumulation patterns and identified the key genes associated with lignin biosynthesis using gas chromatography–mass spectrometry (GC–MS), liquid chromatography–tandem mass spectrometry (LC–MS/MS) and RNA-sequencing (RNA-Seq). Results showed that the contents of total lignin and its precursors exhibited notable declines with tissue maturation. However, the lignin composition was remarkably modified and syringyl lignin was deposited in mature rhizomes, leading to ginger lignification. Transcriptome analysis displayed 32 lignin biosynthetic genes were dramatically downregulated with rhizome development, including caffeoylshikimate esterase (CSE), 4-coumarate-CoA ligase, laccase, cinnamoyl-CoA reductase, cinnamyl-alcohol dehydrogenase, peroxidase and caffeic acid 3-O-methyltransferase, indicating that lignin reduction might be attributed to deficiency in intermediates or the downregulation of key biosynthetic enzymes. Furthermore, overexpressing ZoCSE in Nicotiana benthamiana L. enhanced the total lignin content, suggesting its fundamental role in lignin biosynthesis. RNA-Seq also identified candidate lignin production regulators, including hormone-related genes and NAC/MYB transcription factors (ZoNAC1, ZoNAC4, ZoMYB14 and ZoMYB17). This result provides a molecular basis for lignin accumulation in ginger.
The impact of tree removal on standing grass biomass, seedling establishment and growth of woody species
Authors: Monegi P. , Mkhize N. R. , Tjelele T. J. , Ward D. , Tsvuura Z.
Published: April 2022

The removal of trees in rangelands can create gaps and lead to increased grass production that could suppress subsequent tree seedling establishment and growth. However, gaps can also enhance the growth of remaining trees. We conducted a field experiment at two savanna sites with different soil texture and woody species. We used 24 plots at each site to determine the effect of tree-removal intensities (0%, 10%, 20%, 50%, 75% and 100%) on grass production, tree-seedling establishment and growth, and growth of the remaining large trees. Site 1 was on previously cultivated severely-eroded clay-dominated soils, encroached by a monospecific stand of Vachellia tortilis. Site 2 had never been cultivated, and was on sandy soils with several woody species. At Site 1, 75 and 100% tree removal significantly reduced standing grass biomass towards the end of the first growing season, with no differences towards the end of the second season. At Site 2, tree removal significantly increased standing grass biomass. There was no significant effect of tree removal on tree seedling establishment at Site 1, but at Site 2 tree removal had a significantly negative effect on overall tree seedling establishment. At both sites, there were no significant differences in tree seedling growth. Moderate (50%) to high (75%) removal of trees had a positive effect on the growth of remaining large trees at both study sites. We found that tree seedling establishment could be affected by the level of grass biomass following tree removal, but other factors including soil erosion are also important considerations. Reduced tree competition facilitates growth of remaining large trees. An implication of these findings is that, regardless of the substantial costs of woody plant control, the recovery of key ecosystem services such as an increased forage production may not be realised. However, we recognise that this may be system-specific.
Structural basis for replicase polyprotein cleavage and substrate specificity of main protease from SARS-CoV-2
Authors: Zhao Yao , Zhu Yan , Liu Xiang , Jin Zhenming , Duan Yinkai , Zhang Qi , Wu Chengyao , Feng Lu , Du Xiaoyu , Zhao Jinyi , Shao Maolin , Zhang Bing , Yang Xiuna , Wu Lijie , Ji Xiaoyun , Guddat Luke W. , Yang Kailin , Rao Zihe , Yang Haitao
Published: April 2022

Significance

COVID-19 is a deadly rampaging infectious disease with over 480 million cases worldwide. Unfortunately, effective therapies remain very limited. Novel antiviral agents are urgently needed to combat this global healthcare crisis. Here, we elucidate the structural basis for replicase polyprotein cleavage and substrate specificity of SARS-CoV-2 main protease (M
pro
). Through analyzing a series of high-resolution structures of SARS-CoV-2 M
pro
throughout the proteolytic process, we demonstrate the molecular mechanism of M
pro
in proteolytic processing that confers substrate specificity. Substrate selectivity is revealed using structures of the H41A mutant in complex with six individual native cleavage substrates. Our study underscores the mechanistic function of M
pro
in the viral life cycle, which provides structural insights to develop effective inhibitors against this essential target of SARS-CoV-2.
Picosecond energy transfer in a transition metal dichalcogenide–graphene heterostructure revealed by transient Raman spectroscopy
Authors: Ferrante Carino , Di Battista Giorgio , López Luis E. Parra , Batignani Giovanni , Lorchat Etienne , Virga Alessandra , Berciaud Stéphane , Scopigno Tullio
Published: April 2022

Significance

Hot carrier–based energy harvesting is critically implied in the performances of optoelectronic devices based on van der Waals heterostructures composed by graphene (Gr) and monolayer transition metal dichalcogenides (TMD). The way electron–hole couples initially photogenerated in the TMD are converted into an electric current in Gr is a controversial issue. In this work we identify the interlayer interaction occurring during the first picoseconds following photoexcitation as an energy transfer process that is much faster than (other) photogating phenomena implied in optoelectronic applications.
Rapidly descending dark energy and the end of cosmic expansion
Authors: Andrei Cosmin , Ijjas Anna , Steinhardt Paul J.
Published: April 2022

Significance

Although the universe is expanding at an accelerating rate today, this paper presents a simple mechanism by which a dynamical form of dark energy (known as quintessence) could cause the acceleration to come to end and smoothly transition from expansion to a phase of slow contraction. That raises questions, How soon could this transition occur? And at what point would it be detectable? The conclusions are that the transition could be surprisingly soon, maybe less than 100 million y from now, and yet, for reasons described in the main text, it is not yet detectable today. The scenario is not far-fetched. In fact, it fits naturally with recent theories of cyclic cosmology and conjectures about quantum gravity.