bluuebunny/crossref_metadata_2025 huggingface dataset:
Shock-induced chemical decomposition and overdriven detonation in hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) single crystals
Authors: Winey J. M. , Toyoda Y. , Gupta Y. M.
Published: September 2022

Understanding the differences in the shock compression and detonation response of insensitive high explosives (IHEs) and conventional HEs (CHEs) is a long-standing need in HE science and technology. Having previously examined 1,1-diamino-2,2-dinitroethene (FOX-7) IHE single crystals [Winey et al., J. Appl. Phys. 130, 015902 (2021)], the shock and detonation response of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX)—a widely used CHE—was determined using wave profile measurements in ∼250 μm thick single crystals shock compressed to 63 GPa. In marked contrast to FOX-7, RDX single crystals shocked along the [100] and [111] orientations showed wave profile features consistent with chemical decomposition onset at 15 GPa. These features were more pronounced for [100] RDX, suggesting a higher decomposition rate compared to [111] RDX. At 51 GPa and above, flat-topped single waves were observed for both orientations, showing the classic Chapman–Jouget (C–J) detonation response in which the decomposition is completed within the detonation front. The Hugoniot states and sound speeds determined for the detonation products were similar for both [100] and [111] orientations, showing that the overdriven detonation response for RDX does not depend on crystal orientation. The C–J pressure for RDX single crystals (35 GPa)—determined experimentally—is comparable to that of FOX-7. However, compared to FOX-7, chemical decomposition onset for RDX occurs at much lower pressures and the overdriven C–J detonation response occurs at higher pressures. The present findings constitute the first experimental comparison of the shock and detonation response of conventional and insensitive HE single crystals over a broad pressure range below and above the C–J pressure.
Kinetic formulation of Tolman–Ehrenfest effect: Non-ideal fluids in Schwarzschild and Kerr space-times
Authors: Cremaschini Claudio , Kovář Jiří , Stuchlík Zdeněk , Tessarotto Massimo
Published: September 2022

A review of the original thermodynamic formulation of the Tolman–Ehrenfest effect prescribing the temperature profile of uncharged fluid at thermal equilibrium forming stationary configurations in curved space-time is proposed. A statistical description based on the relativistic kinetic theory is implemented. In this context, the Tolman–Ehrenfest relation arises in the Schwarzschild space-time for collisionless uncharged particles at Maxwellian kinetic equilibrium. However, the result changes considerably when non-ideal fluids, i.e., non-Maxwellian distributions, are treated, whose statistical temperature becomes non-isotropic and gives rise to a tensor pressure. This is associated with phase-space anisotropies in the distribution function, occurring both for diagonal and non-diagonal metric tensors, exemplified by the Schwarzschild and Kerr metrics, respectively. As a consequence, it is shown that for these systems, it is not possible to define a Tolman–Ehrenfest relation in terms of an isotropic scalar temperature. Qualitative properties of the novel solution are discussed.
Spacing effect on the vortex-induced vibrations of near-wall flexible cylinders in the tandem arrangement
Authors: Zhang Zhimeng , Ji Chunning
Published: September 2022

The vibration responses and flow dynamics in the vortex-induced vibrations of two near-wall flexible cylinders in the tandem arrangement are investigated through three-dimensional direct numerical simulations with the spacing ratio s/D =1.5–6 (D = diameter of the cylinder), gap ratio G/D = 0.8, cylinder length of 25D, and Reynolds number of 500. The in-line (IL) and crossflow (CF) vibrations are predominated by the first-order mode along the span. The upstream cylinder oscillates at a higher CF amplitude than the downstream one, and the maximum IL and CF vibration amplitudes of the tandem cylinders are both smaller than those of the single cylinder. The dominant frequencies of IL and CF oscillation are identical for the tandem cylinders, and they are larger than that of the single cylinder. The smaller mean drag and larger rms drag occur on the downstream cylinder than in the upstream counterpart. The difference between the spanwise rms lift of the two cylinders reduces as the s/D increases. Different flow types are observed along the flexible cylinders: at s/D = 1.5–2, an “extended-body regime” and a “reattachment regime” are excited near the two-ends and the middle regions along the span, respectively; at s/D = 3, a reattachment regime and a “co-shedding regime” appear; at s/D = 4–6, the co-shedding regime is observed but with different vorticities related to the vibration amplitudes. At s/D = 3, the wall proximity induces multi-frequencies in both the IL and CF oscillations, compared to single-frequency oscillations in wall-free conditions. The lower IL and higher CF vibration amplitudes are excited in the near-wall conditions. Weak “2S” and the typical 2S vortex shedding patterns are observed in the near-wall and wall-free conditions, respectively.
The thermodynamics of pressurized methanol: A simple hydrogen-bonded liquid as a touchstone for experiment and computer simulations
Authors: Fomin Yu. D. , Dzhavadov L. N. , Tsiok E. N. , Ryzhov V. N. , Brazhkin V. V.
Published: September 2022

Methanol as a basic liquid and the simplest alcohol is widely used in industry and scientific experiments. However, there are still no reliable data on the thermodynamic properties of methanol at high pressure. Here, we present an experimental and computational study of the thermodynamic properties of liquid methanol under high pressure up to 15 kbar, which significantly exceeds previously reported pressures. A temperature response to a small adiabatic change in pressure has been measured using a piston–cylinder apparatus. We have compared our experimental results with the literature data for lower pressures and NIST approximations. We find that all existing experimental data do not agree with each other and with our experiments. The NIST approximations are mainly based on low pressure data and appear to be unreliable in the high pressure region, giving even qualitatively wrong results. OPLS and COMPASS force field models have been used in the method of molecular dynamics. The agreement of molecular simulation with our experimental data is definitely unsatisfactory, which means that the most common computational models of methanol are not sufficiently good. We hope that these experimental data and approximations will help in developing better computational models.
Interpenetrating gels in binary suspensions of DNA nanostars
Authors: Lattuada E. , Pietrangeli T. , Sciortino F.
Published: September 2022

We experimentally investigate the equilibrium gel formation in a binary mixture of DNA nanostars. The binding rules, encoded in the DNA sequence of the nanostar binding ends, are such that each component is able to form only intra-species bonds. Reducing the excluded volume by properly designing the DNA nanostars, we show that two interpenetrating unconnected gels form in the sample on cooling, each of the two forms at a temperature controlled by the selected binding DNA sequence. The dynamic light scattering correlation functions show a non-common three-step relaxation process due to the splitting of the slow relaxation into two distinct decays, each of them reflecting the relaxation dynamics of one of the two networks.
Microhydration of the metastable N-protomer of 4-aminobenzoic acid by condensation at 80 K: H/D exchange without conversion to the more stable O-protomer
Authors: Khuu Thien , Stropoli Santino J. , Greis Kim , Yang Nan , Johnson Mark A.
Published: September 2022

4-aminobenzoic acid (4ABA) is a model scaffold for studying solvent-mediated proton transfer. Although protonation at the carboxylic group (O-protomer) is energetically favored in the gas phase, the N-protomer, where the proton remains on the amino group, can be kinetically trapped by electrospray ionization of 4ABA in an aprotic solvent such as acetonitrile. Here, we report the formation of the hydrated deuterium isotopologues of the N-protomers, RND3+·(H2O)n=1–3, (R = C6H4COOD), which are generated by condensing water molecules onto the bare N-protomers in a liquid nitrogen cooled, radiofrequency octopole ion trap at 80 K. The product clusters are then transferred to a 20 K cryogenic ion trap where they are tagged with weakly bound D2 molecules. The structures of these clusters are determined by analysis of their vibrational patterns, obtained by resonant IR photodissociation. The resulting patterns confirm that the metastable N-protomer configuration remains intact even when warmed by the sequential condensation of water molecules. The attachment of H2O molecules onto the RND3+ head group also affords the opportunity to explore the possibility of H/D exchange between the acid scaffold and the proximal water network. The spectroscopic results establish that although the RND3+·(H2O)n=1,2 clusters are formed without H/D exchange, the n = 3 cluster exhibits about 10% H/D exchange as evidenced by the appearance of the telltale HOD bands. The site of exchange on the acid is determined to be the acidic OH group by the emergence of the OH stretching fundamental in the –COOH motif.
Liquid to solid transition of elastin condensates
Authors: Vidal Ceballos Alfredo , Díaz A Jairo A. , Preston Jonathan M. , Vairamon Christo , Shen Christopher , Koder Ronald L. , Elbaum-Garfinkle Shana
Published: September 2022

Liquid–liquid phase separation of tropoelastin has long been considered to be an important early step in the complex process of elastin fiber assembly in the body and has inspired the development of elastin-like peptides with a wide range of industrial and biomedical applications. Despite decades of study, the material state of the condensed liquid phase of elastin and its subsequent maturation remain poorly understood. Here, using a model minielastin that mimics the alternating domain structure of full-length tropoelastin, we examine the elastin liquid phase. We combine differential interference contrast (DIC), fluorescence, and scanning electron microscopy with particle-tracking microrheology to resolve the material transition occurring within elastin liquids over time in the absence of exogenous cross-linking. We find that this transition is accompanied by an intermediate stage marked by the coexistence of insoluble solid and dynamic liquid phases giving rise to significant spatial heterogeneities in material properties. We further demonstrate that varying the length of the terminal hydrophobic domains of minielastins can tune the maturation process. This work not only resolves an important step in the hierarchical assembly process of elastogenesis but further contributes mechanistic insight into the diverse repertoire of protein condensate maturation pathways with emerging importance across biology.
Pest population dynamics are related to a continental overwintering gradient
Authors: Lawton Douglas , Huseth Anders S. , Kennedy George G. , Morey Amy C. , Hutchison William D. , Reisig Dominic D. , Dorman Seth J. , Dillard DeShae , Venette Robert C. , Groves Russell L. , Adamczyk John J. , Barbosa Dos Santos Izailda , Baute Tracey , Brown Sebe , Burkness Eric , Dean Ashley , Dively Galen P. , Doughty Hélène B. , Fleischer Shelby J. , Green Jessica , Greene Jeremy K. , Hamilton Krista , Hodgson Erin , Hunt Thomas , Kerns David , Leonard Billy Rogers , Malone Sean , Musser Fred , Owens David , Palumbo John C. , Paula-Moraes Silvana , Peterson Julie A. , Ramirez Ricardo , Rondon Silvia I. , Schilder Tracy L. , Seaman Abby , Spears Lori , Stewart Scott D. , Taylor Sally , Towles Tyler , Welty Celeste , Whalen Joanne , Wright Robert , Zuefle Marion
Published: September 2022

Overwintering success is an important determinant of arthropod populations that must be considered as climate change continues to influence the spatiotemporal population dynamics of agricultural pests. Using a long-term monitoring database and biologically relevant overwintering zones, we modeled the annual and seasonal population dynamics of a common pest,
Helicoverpa zea
(Boddie), based on three overwintering suitability zones throughout North America using four decades of soil temperatures: the southern range (able to persist through winter), transitional zone (uncertain overwintering survivorship), and northern limits (unable to survive winter). Our model indicates
H. zea
population dynamics are hierarchically structured with continental-level effects that are partitioned into three geographic zones. Seasonal populations were initially detected in the southern range, where they experienced multiple large population peaks. All three zones experienced a final peak between late July (southern range) and mid-August to mid-September (transitional zone and northern limits). The southern range expanded by 3% since 1981 and is projected to increase by twofold by 2099 but the areas of other zones are expected to decrease in the future. These changes suggest larger populations may persist at higher latitudes in the future due to reduced low-temperature lethal events during winter. Because
H. zea
is a highly migratory pest, predicting when populations accumulate in one region can inform synchronous or lagged population development in other regions. We show the value of combining long-term datasets, remotely sensed data, and laboratory findings to inform forecasting of insect pests.
Miat and interacting protein Metadherin maintain a stem-like niche to promote medulloblastoma tumorigenesis and treatment resistance
Authors: Peng Kai-Lin , Vasudevan Harish N. , Lockney Dennis T. , Baum Rachel , Hendrickson Ronald C. , Raleigh David R. , Schmitt Adam M.
Published: September 2022

Long noncoding RNAs (lncRNAs) play essential roles in the development and progression of many cancers. However, the contributions of lncRNAs to medulloblastoma (MB) remain poorly understood. Here, we identify
Miat
as an lncRNA enriched in the sonic hedgehog group of MB that is required for maintenance of a treatment-resistant stem-like phenotype in the disease. Loss of
Miat
results in the differentiation of tumor-initiating, stem-like MB cells and enforces the differentiation of tumorigenic stem-like MB cells into a nontumorigenic state.
Miat
expression in stem-like MB cells also facilitates treatment resistance by down-regulating p53 signaling and impairing radiation-induced cell death, which can be reversed by therapeutic inhibition of
Miat
using antisense oligonucleotides. Mechanistically, the RNA binding protein Metadherin (Mtdh), previously linked to resistance to cytotoxic therapy in cancer, binds to
Miat
in stem-like MB cells. Like the loss of
Miat
, the loss of
Mtdh
reduces tumorigenicity and increases sensitivity to radiation-induced death in stem-like MB cells. Moreover, Miat and Mtdh function to regulate the biogenesis of several microRNAs and facilitate tumorigenesis and treatment resistance. Taken together, these data reveal an essential role for the lncRNA
Miat
in sustaining a treatment-resistant pool of tumorigenic stem-like MB cells.
Epstein-Barr virus protein BKRF4 restricts nucleosome assembly to suppress host antiviral responses
Authors: Chen Jiao , Lu Zuer , Gong Weibin , Xiao Xue , Feng Xiaoli , Li Wei , Shan Shan , Xu Dongyi , Zhou Zheng
Published: September 2022

Inhibition of host DNA damage response (DDR) is a common mechanism used by viruses to manipulate host cellular machinery and orchestrate viral life cycles. Epstein-Barr virus tegument protein BKRF4 associates with cellular chromatin to suppress host DDR signaling, but the underlying mechanism remains elusive. Here, we identify a BKRF4 histone binding domain (residues 15–102, termed BKRF4-HBD) that can accumulate at the DNA damage sites to disrupt 53BP1 foci formation. The high-resolution structure of the BKRF4-HBD in complex with a human H2A–H2B dimer shows that BKRF4-HBD interacts with the H2A–H2B dimer via the N-terminal region (NTR), the DWP motif (residues 80–86 containing D81, W84, P86), and the C-terminal region (CTR). The “triple-anchor” binding mode confers BKRF4-HBD the ability to associate with the partially unfolded nucleosomes, promoting the nucleosome disassembly. Importantly, disrupting the BKRF4–H2A–H2B interaction impairs the binding between BKRF4-HBD and nucleosome in vitro and inhibits the recruitment of BKRF4-HBD to DNA breaks in vivo. Together, our study reveals the structural basis of BKRF4 bindings to the partially unfolded nucleosome and elucidates an unconventional mechanism of host DDR signal attenuation.
Loss-of-function mutation survey revealed that genes with background-dependent fitness are rare and functionally related in yeast
Authors: Caudal Elodie , Friedrich Anne , Jallet Arthur , Garin Marion , Hou Jing , Schacherer Joseph
Published: September 2022

In natural populations, the same mutation can lead to different phenotypic outcomes due to the genetic variation that exists among individuals. Such genetic background effects are commonly observed, including in the context of many human diseases. However, systematic characterization of these effects at the species level is still lacking to date. Here, we sought to comprehensively survey background-dependent traits associated with gene loss-of-function (LoF) mutations in 39 natural isolates of
Saccharomyces cerevisiae
using a transposon saturation strategy. By analyzing the modeled fitness variability of a total of 4,469 genes, we found that 15% of them, when impacted by a LoF mutation, exhibited a significant gain- or loss-of-fitness phenotype in certain natural isolates compared with the reference strain S288C. Out of these 632 genes with predicted background-dependent fitness effects, around 2/3 impact multiple backgrounds with a gradient of predicted fitness change while 1/3 are specific to a single genetic background. Genes related to mitochondrial function are significantly overrepresented in the set of genes showing a continuous variation and display a potential functional rewiring with other genes involved in transcription and chromatin remodeling as well as in nuclear–cytoplasmic transport. Such rewiring effects are likely modulated by both the genetic background and the environment. While background-specific cases are rare and span diverse cellular processes, they can be functionally related at the individual level. All genes with background-dependent fitness effects tend to have an intermediate connectivity in the global genetic interaction network and have shown relaxed selection pressure at the population level, highlighting their potential evolutionary characteristics.
Communicating amounts in terms of commonly used budgeting periods increases intentions to claim government benefits
Authors: De La Rosa Wendy , Sussman Abigail B. , Giannella Eric , Hell Maximilian
Published: September 2022

Millions of eligible families did not claim their 2021 expanded child tax credit (CTC), collectively forgoing billions of dollars. To address this problem, many policymakers focused on increasing awareness of the CTC by highlighting that families could receive up to $3,600 a year per child. However, people rarely budget on a yearly basis. We propose that communicating the CTC benefit amount in terms of commonly used budgeting periods (e.g., $300 a month) instead of uncommonly used budgeting periods (e.g., $3,600 a year) could increase interest in claiming the CTC. Two large-scale field experiments (n=16,696) among low-income individuals support this account. Using common (vs. uncommon) budgeting periods to describe CTC benefit amounts increased CTC claiming intentions by 16 to 26%. A third large-scale field experiment (n=14,178) demonstrated that encouraging people to consider different budgeting periods moderated these effects. These results suggest that communicating amounts in terms of common budgeting periods is a simple, cost-effective way to stimulate interest in claiming government benefits.
Riboflavin synthesis from gaseous nitrogen and carbon dioxide by a hybrid inorganic-biological system
Authors: Sherbo Rebecca S. , Silver Pamela A. , Nocera Daniel G.
Published: September 2022

Microbes can provide a more sustainable and energy-efficient method of food and nutrient production compared to plant and animal sources, but energy-intensive carbon (e.g., sugars) and nitrogen (e.g., ammonia) inputs are required. Gas-fixing microorganisms that can grow on H
2
from renewable water splitting and gaseous CO
2
and N
2
offer a renewable path to overcoming these limitations but confront challenges owing to the scarcity of genetic engineering in such organisms. Here, we demonstrate that the hydrogen-oxidizing carbon- and nitrogen-fixing microorganism
Xanthobacter autotrophicus
grown on a CO
2
/N
2
/H
2
gas mixture can overproduce the vitamin riboflavin (vitamin B
2
). We identify plasmids and promoters for use in this bacterium and employ a constitutive promoter to overexpress riboflavin pathway enzymes. Riboflavin production is quantified at 15 times that of the wild-type organism. We demonstrate that riboflavin overproduction is maintained when the bacterium is grown under hybrid inorganic-biological conditions, in which H
2
from water splitting, along with CO
2
and N
2
, is fed to the bacterium, establishing the viability of the approach to sustainably produce food and nutrients.
Deceptive clickbaits in the relevance-theoretic lens
Authors: Jodłowiec Maria
Published: September 2022

This paper explores the nature of clickbaiting as a form of viral journalism from a relevance-theoretic perspective (Sperber and Wilson 1995; Wilson and Sperber 2012). The focus is on deceptive clickbaits, i.e., manipulative internet headlines whose interpretation, based on the way they are worded, leads to opening an information gap, thus luring the reader into clicking on the link provided with a view to increasing the website traffic. It is highlighted that such headlines exploit linguistic underdeterminacy, and unlike felicitous headlines, which provide an accurate representation of the article content and therefore play the role of relevance optimizers (Dor 2003), deceptive clickbaits induce recipients to generate interpretations which arouse their intense curiosity but are ultimately incompatible with the article’s content. The paper shows how relevance theory can explain the interpretation bias that the reader of deceptive clickbaits falls prey to and advances the idea that there is affinity in this respect between deceptive clickbaits and jokes.
NCOA4 drives ferritin phase separation to facilitate macroferritinophagy and microferritinophagy
Authors: Ohshima Tomoko , Yamamoto Hayashi , Sakamaki Yuriko , Saito Chieko , Mizushima Noboru
Published: September 2022

A ferritin particle consists of 24 ferritin proteins (FTH1 and FTL) and stores iron ions within it. During iron deficiency, ferritin particles are transported to lysosomes to release iron ions. Two transport pathways have been reported: macroautophagy and ESCRT-dependent endosomal microautophagy. Although the membrane dynamics of these pathways differ, both require NCOA4, which is thought to be an autophagy receptor for ferritin. However, it is unclear whether NCOA4 only acts as an autophagy receptor in ferritin degradation. Here, we found that ferritin particles form liquid-like condensates in a NCOA4-dependent manner. Homodimerization of NCOA4 and interaction between FTH1 and NCOA4 (i.e., multivalent interactions between ferritin particles and NCOA4) were required for the formation of ferritin condensates. Disruption of these interactions impaired ferritin degradation. Time-lapse imaging and three-dimensional correlative light and electron microscopy revealed that these ferritin–NCOA4 condensates were directly engulfed by autophagosomes and endosomes. In contrast, TAX1BP1 was not required for the formation of ferritin–NCOA4 condensates but was required for their incorporation into autophagosomes and endosomes. These results suggest that NCOA4 acts not only as a canonical autophagy receptor but also as a driver to form ferritin condensates to facilitate the degradation of these condensates by macroautophagy (i.e., macroferritinophagy) and endosomal microautophagy (i.e., microferritinophagy).
Novel features of Schwarzschild-like black hole of Lorentz violating bumblebee gravity
Authors: Izmailov Ramil N , Nandi Kamal K
Published: September 2022

A possible avenue for observing quantum gravity (QG) effects at low energy scales is to introduce spontaneous Lorentz violation (LV) in new models of gravity theories. One such model in the literature is bumblebee gravity yielding Schwarzschild-like black hole and weak field Solar System observations involve LV corrections characterized by the parameter ℓ. Here we first show that these LV corrections have a novel genesis in the conical angle Δ = πb subtended at the origin of the spacetime of massless bumblebee gravity. Exploiting the resultant asymptotic light deflection angle πb
−1 as a new input in the exact deflection formula, we next study the strong field lensing properties of the Schwarzschild-like black hole exploring how they differ from those of the Schwarzschild black hole of general relativity. It is shown that the angular image separation and ratio of fluxes could respectively be s ∼ e
πℓ
and r ∼ e−πℓ
times those of the Schwarzschild black hole (ℓ = 0). However, the shadow of the Schwarzschild-like black hole is independent of ℓ suggesting that observations of shadow radii cannot reveal QG effects. Finally, we raise an interesting issue about the measurability of the LV corrections caused by strong field lensing. An appendix briefly outlines lensing by the spinning bumblebee black hole.
A novel electromagnetic microactuator with a stainless steel mas-spring structure
Authors: Tahmasebipour Mohammad , Dehghan Mohammad
Published: September 2022

Microactuators are one of the main components of the microelectromechanical and microfluidic systems and play a key role in their development. Many such systems, e.g. micropumps and microvalves, utilize an electromagnetic microactuator with a displacement range of a few micrometers traversed within a few seconds. Most of the electromagnetic microactuators have low lifetime and fracture toughness or low recovery speed. Microactuators with metallic mass-spring structure can overcome the mentioned disadvantages or limitations. This paper presents the design and fabrication of a novel stainless steel electromagnetic microactuator fabricated using micro-wire electrical discharge machining. The microactuator in question consists of a mass-and-spring structure made of 304 stainless steel, a permanent magnet made of NdFeB, and a microcoil. The impacts of the number of turns, distance, and electric current on the magnetic field of the microcoil and the displacement of the microactuator membrane with time have been investigated to determine the microactuator characteristics. The results indicated a displacement of about ±10 (20) μm within 7 s for an electric current of 1100 mA. This microactuator exhibits a faster response compared to the similar microactuators. Consequently, it can be used at higher operating frequencies and, thus, improves the fluid flow in micropumps.
Optical characterisation of InGaN-based microdisk arrays with nanoporous GaN/GaN DBRs
Authors: Fletcher Peter , Martínez de Arriba Guillem , Tian Ye , Poyiatzis Nicolas , Zhu Chenqi , Feng Peng , Bai Jie , Wang Tao
Published: September 2022

Optically pumped whispering gallery mode (WGM) lasing has been observed in many freestanding microdisk structures. Dry etching is normally used to fabricate the microdisks, which causes severe sidewall damage, resulting in degradation of lasing performance, especially for ultra-small electrically-injected devices. In this paper, we demonstrate high quality microdisk cavities with 3.5 µm diameter, by combining a selective overgrowth approach and an epitaxial lattice-matched distributed Bragg reflector (DBR), topped with a highly reflective (>99%) dielectric DBR. InGaN polaritons are found to occur in the high-quality microcavities. WGM modes are measured, with the positions in good agreement with finite difference time domain simulations. Furthermore, lasing behaviour is observed with a threshold at 410 µW and a dominant mode at 488 nm.
Nematic twist-bend phase of a bent liquid crystal dimer: field-induced deformations of the helical structure and macroscopic polarization
Authors: Patranabish Sourav , Sinha Aloka , Kanakala Madhu B , Yelamaggad C V
Published: September 2022

The twist-bend nematic (Ntb) phase is a recent addition to the family of nematic (N) phases of liquid crystals (LCs). A net polar order in the Ntb phase under an external electric field is interesting and it was predicted in several recent theoretical studies. We investigated the field-induced polarization behaviour, dielectric, and electro-optic properties of a bent LC dimer CB7CB in the N and Ntb phases. A threshold-dependent polarization current response was obtained in both the phases under triangular and square-wave input electric fields, existing till frequencies as high as 150 Hz. The polarization switching times were found in ∼1 ms region, especially in the N phase. In the Ntb phase, electric field-induced deformation of the helical structure was observed, like ferroelectric LCs. Dielectric measurements revealed the presence of cybotactic clusters via collective relaxations. The dielectric anisotropy (Δϵ) is negative at the frequencies of polarization measurements. The net polarization resulted from field-induced reorientation of cybotactic clusters and additionally from the field-induced deformation of helical structures in the Ntb phase. We explored the possibility of ionic contributions to the net polarization by synthesizing TiO2 nanoparticles (NPs) dispersed CB7CB LC nanocomposite. Incorporation of the NPs resulted in reduction of the collective order, increase in the ionic impurity content and conductivity, but an extinction of the field-induced polarization response. Our results demonstrate that the net polarization has competing contributions from both ferroelectric-like and ionic origin (up to ∼10 Hz) in the LC phases, but it becomes dominantly ferroelectric-like at higher frequencies.
Radiation dose aspects and establishment of diagnostic reference levels for 90Y radioembolisation during angiographic procedure
Authors: Opitz Marcel , Zensen Sebastian , Ludwig Johannes Maximilian , Weber Manuel , Alatzides Georgios , Seifert Robert , Grüneisen Johannes , Theysohn Jens Matthias , Bos Denise , Schaarschmidt Benedikt Michael
Published: September 2022

90Y radioembolisation (RE) is an angiographic procedure used in patients with both primary and secondary hepatic malignancies. Local tumour control can be achieved by short range tumour irradiation by the regional intra-arterial administration of glass or resin microspheres loaded with 90yttrium that accumulate in the tumorous tissue. The aim of this study was to investigate the radiation exposure of RE and to establish a local diagnostic reference level (DRL). In this retrospective study, dose data from 397 procedures in 306 patients (mean age 67.4 ± 10.6 years, 82 female) who underwent RE between 06/2017 and 01/2022 using one of two different angiography systems were analysed. DRL was set as the 75th percentile of the dose distribution. In the overall population, dose area product (DAP) (median (interquartile range, IQR)) was 26 Gy cm2 (IQR 12–50) with a median fluoroscopy time (FT) of 4.5 min (IQR 2.9–8.0). FT and DAP increased significantly with the number of infusion positions (median, IQR): one position 23 Gy cm2 (12–46), two positions 33 Gy cm2 (14–60), three positions 50 Gy cm2 (24–82) (p < 0.0001). Local DRL is 47 Gy cm2 for RE and 111 Gy cm2 for RE with additional embolisation. Radiation exposure and FT are significantly higher with increasing number of infusion positions as well as additional embolisation. Our established DRLs for RE may serve as a benchmark for dose optimisation.
Phase stability and precipitation modeling in neutron irradiated Zr–2% Nb alloy
Authors: Kharchenko V O , Xin Tianyuan , Wu Lu , Kharchenko D O , Kupriienko V V , Shuda I O
Published: September 2022

Precipitation at thermal treatment and radiation induced precipitation in zirconium alloy with low concentration of Nb is studied. A corresponding phase field model by taking into account ballistic mixing and dynamics of point defects with their sinks (dislocation loops) is developed. Analysis of precipitation dynamics and statistical distributions of precipitates with local rearrangement of non-equilibrium vacancies around precipitates is provided. It is shown that the competition between ballistic mixing and the thermodynamic force plays a major role in kinetics of radiation induced precipitation and precipitates dissolution. The estimation of mechanical properties of the material at irradiation at reactor conditions is provided.
‘Switch to love, switch to kill—dose and light co-regulate iron single-atom nanozyme to modulate cell fate
Authors: Zhe Yadong , Liu Jia , Zhao Zhiqiang , Li Zaoming , Li Kai , Lin Yuqing
Published: September 2022

Remote control of cells and the regulation of cell events at the molecular level are of great interest to the biomedical field. In addition to mechanical forces and genes, chemical compounds and light play pivotal roles in regulating cell fate, which have boosted the fast growth of biology. Herein, we synthesized light-regulated, atomically dispersed Fe-N4 immobilized on a carbon substrate nanozyme (Fe-N/C single atom catalysts), whose peroxidase- and catalase-like properties can be enhanced by 120% and 135%, respectively, under 808-nm laser irradiation through the photothermal effect of Fe-N/C. Interestingly, a switch to love/switch to kill interaction between Fe-N/C dose and near-infrared (NIR) light co-regulating the Fe-N/C nanozyme to modulate cell fate was discovered. Based on this, we found that under NIR light irradiation, when the dose of Fe-N/C is low, it can scavenge more reactive oxygen species (ROS) and achieve cell protection; when the dose of Fe-N/C is too high, it tended to lead to cell apoptosis. This work not only provides an effective strategy for the regulation of nanozyme activity but also realizes the dual-functional application of nanozyme materials for the treatment of some specific diseases.
Magnetic anisotropy in the exchange-biased laser-patterned thin Co/CoO films
Authors: Perzanowski M , Polit O , Chojenka J , Sas W , Zarzycki A , Marszalek M
Published: September 2022

Materials exhibiting an exchange bias effect are a class of magnetic systems that have a wide range of possible technological applications e.g. in sensors, read heads, and spintronic devices. In this study, we demonstrate the effect of laser interference patterning on the magnetic properties of Pd/CoO/Co/Pd multilayers. Laser patterning creates arrays of well-ordered stripes, rectangles, and squares on the substrate surface. We found that the laser treatment caused magnetic softening of the structure edges while the centers of the objects remained unchanged and exhibited the exchange bias effect. In this study we focused on the shape and configurational magnetic anisotropies induced by patterning and showed that the magnetic properties varied depending on the angle at which the external magnetic field was applied with respect to the pattern geometry.
Co3O4-MoSe2@C nanocomposite as a multi-functional catalyst for electrochemical water splitting and lithium-oxygen battery
Authors: Yu Wenjing , Zhang Shaohua , Gao Kun , Lin Xiangyun , Han Yuyang , Zhang Zhipan
Published: September 2022

Co3O4-MoSe2@C nanocomposite has been prepared by a convenient method via combining hydrothermally synthesized MoSe2@C and Co3O4. When catalyzing the hydrogen evolution reaction and oxygen evolution reaction, the catalyst features low overpotentials of 144 mV and 360 mV (both at 10 mA cm−2 current density), respectively. It can also serve as the cathode in the lithium-oxygen battery and the device shows a low charging-discharging overpotential of 1.50 V with a stable performance of over 200 cycles at current density of 1000 mA g−1, shedding light on the design and synthesis of novel multifunctional electrocatalysts for energy conversions.
An integrative web-based software tool for multi-dimensional pathology whole-slide image analytics
Authors: Shen Alice , Wang Fusheng , Paul Saptarshi , Bhuvanapalli Divya , Alayof Jacob , Farris Alton B , Teodoro George , Brat Daniel J , Kong Jun
Published: September 2022

Objective. In the era of precision medicine, human tumor atlas-oriented studies have been significantly facilitated by high-resolution, multi-modal tissue based microscopic pathology image analytics. To better support such tissue-based investigations, we have developed Digital Pathology Laboratory (DPLab), a publicly available web-based platform, to assist biomedical research groups, non-technical end users, and clinicians for pathology whole-slide image visualization, annotation, analysis, and sharing via web browsers. Approach. A major advancement of this work is the easy-to-follow methods to reconstruct three-dimension (3D) tissue image volumes by registering two-dimension (2D) whole-slide pathology images of serial tissue sections stained by hematoxylin and eosin (H&E), and immunohistochemistry (IHC). The integration of these serial slides stained by different methods provides cellular phenotype and pathophysiologic states in the context of a 3D tissue micro-environment. DPLab is hosted on a publicly accessible server and connected to a backend computational cluster for intensive image analysis computations, with results visualized, downloaded, and shared via a web interface. Main results. Equipped with an analysis toolbox of numerous image processing algorithms, DPLab supports continued integration of community-contributed algorithms and presents an effective solution to improve the accessibility and dissemination of image analysis algorithms by research communities. Significance. DPLab represents the first step in making next generation tissue investigation tools widely available to the research community, enabling and facilitating discovery of clinically relevant disease mechanisms in a digital 3D tissue space.
The design and evaluation of single-channel loopole coils at 7T MRI
Authors: Zheng Mengxuan , Gao Yang , Quan Zhiyan , Zhang Xiaotong
Published: September 2022

Objective. Improving the local uniformity of

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field for awake monkey brain magnetic resonance imaging (MRI) at ultra-high fields while facilitating convenient placement and fixation of MRI-compatible multimodal devices for neuroscience study, can eventually advance our understanding of the primate’s brain organization. Approach. A group of single-channel RF coils including conventional loop coils and loopole coils sharing the same size and shape were designed for comparison; their performance as the transmit coil was quantitatively evaluated through a series of numerical electromagnetic (EM) simulations, and further verified by using 7T MRI over a saline phantom and a monkey in vivo. Main results. Compared to conventional loop coils, the optimized loopole coil brought up to 23.5%

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uniformity improvement for monkey brain imaging in EM simulations, and this performance was further verified over monkey brain imaging at 7T in vivo. Importantly, we have systematically explored the underlying mechanism regarding the relationship between loopole coils’ current density distribution and

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uniformity, observing that it can be approximated as a sinusoidal curve. Significance. The proposed loopole coil design can improve the imaging quality in awake and behaving monkeys, thus benefiting advanced brain research at UHF.
Design, fabrication and experimental demonstration of a highly sensitive SQUID-based accelerometer
Authors: Kim Gracia , Choi In Mook
Published: September 2022

In this paper, a newly designed accelerometer based on a SQUID detection technology and the experimental results are presented. The levitated proof mass was manufactured in the shape that combines a disk and a cylinder on the basis of an earlier patent by the authors. The advantage of this shape is, given that the bottom part is cylindrical, even if the proof mass is mounted mechanically tilted, it can be moved to the center depending on the magnetic flux. The inside of the accelerometer is unobservable after the sealing of the superconducting housing; therefore, the initial set current values on both the solenoid and flat spiral coil are crucial. It was easily able to determine the levitation status at equilibrium position of the proof mass by investigating the inductance change according the persistent current for sensing and solenoid coils. At the levitation status, the movement of the proof mass caused by an external acceleration could be detected with a SQUID optimization. Accordingly, levitation experimental results and the flux noise spectra of the levitated proof mass are described.
WITHDRAWN: Simulation and analysis of heat dissipation performance of octagonal slotted circle based on LBM lattice algorithm
Authors: Wang Jie , Yang Mo
Published: September 2022

This article has been withdrawn by IOP Publishing following an admission by the authors that this article may contain research errors.

IOP Publishing has investigated in line with the COPE guidelines with the help of an independent subject expert, who has found the article contains numerous flaws, which bring into question the reliability of the work presented. As such, IOP Publishing agree that this work should be withdrawn.
Boltzmann or Bogoliubov?
Approaches compared in gravitational particle production
Authors: Kaneta Kunio , Lee Sung Mook , Oda Kin-ya
Published: September 2022

Gravitational particle production is a minimal contribution to reheating the Universe after the end of inflation.
To study this production channel, two different approaches have commonly been considered, one of which is based on the Boltzmann equation, and the other is based on the Bogoliubov transformation.
Each of these has pros and cons in practice.
The collision term in the Boltzmann equation can be computed based on quantum field theory in the Minkowski spacetime, and thus many techniques have been developed so far.
On the other hand, the Bogoliubov approach may deal with the particle production beyond the perturbation theory and is able to take into account the effect of the curved spacetime, whereas in many cases one should rely on numerical methods, such as lattice computation.
We show by explicit numerical and analytical computations of the purely gravitational production of a scalar that these two approaches give consistent results for particle production with large momenta during reheating, whereas the Boltzmann approach is not capable of computing particle production out of vacuum during inflation.
We also provide analytic approximations of the spectrum of produced scalar with/without mass for the low momentum regime obtained from the Bogoliubov approach.
Comment on ‘A physics perspective on collective animal behavior’ 2022 Phys. Biol.
19 021004
Authors: Reynolds Andy M
Published: September 2022

In his insightful and timely review Ouellette (2022 Phys. Biol.
19 021004) noted three theoretical impediments to progress in understanding and modelling collective animal behavior. Here through novel analyses and by drawing on the latest research I show how these obstacles can be either overcome or negated. I suggest ways in which recent advances in the physics of collective behavior provide significant biological information.
Feasibility of epidural temporal interference stimulation for minimally invasive electrical deep brain stimulation: simulation and phantom experimental studies
Authors: Lee Sangjun , Park Jimin , Choi Da Som , Lim Seokbeen , Kwak Youngjong , Jang Dong Pyo , Kim Dong Hwan , Ji Han Bi , Choy Young Bin , Im Chang-Hwan
Published: September 2022

Objective. Temporal interference stimulation (TIS) has shown the potential as a new method for selective stimulation of deep brain structures in small animal experiments. However, it is challenging to deliver a sufficient temporal interference (TI) current to directly induce an action potential in the deep area of the human brain when electrodes are attached to the scalp because the amount of injection current is generally limited due to safety issues. Thus, we propose a novel method called epidural TIS (eTIS) to address this issue; in this method, the electrodes are attached to the epidural surface under the skull. Approach. We employed finite element method (FEM)-based electric field simulations to demonstrate the feasibility of eTIS. We first optimized the electrode conditions to deliver maximum TI currents to each of the three different targets (anterior hippocampus, subthalamic nucleus, and ventral intermediate nucleus) based on FEM, and compared the stimulation focality between eTIS and transcranial TIS (tTIS). Moreover, we conducted realistic skull-phantom experiments for validating the accuracy of the computational simulation for eTIS. Main results. Our simulation results showed that eTIS has the advantage of avoiding the delivery of TI currents over unwanted neocortical regions compared with tTIS for all three targets. It was shown that the optimized eTIS could induce neural action potentials at each of the three targets when a sufficiently large current equivalent to that for epidural cortical stimulation is injected. Additionally, the simulated results and measured results via the phantom experiments were in good agreement. Significance. We demonstrated the feasibility of eTIS, facilitating more focalized and stronger electrical stimulation of deep brain regions than tTIS, with the relatively less invasive placement of electrodes than conventional deep brain stimulation via computational simulation and realistic skull phantom experiments.