bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimised operation study of load aggregator based on UCCP‐IDR model
Authors: Wang Lei , Ma Chaoqun , Zhu Liuzhu , Wang Xuli , Yin Chenxu , Cong Hao , Shi Tiancheng
Published: March 2022

With the increasing development of integrated energy systems and the continuous promotion of integrated demand response (IDR) research, residential users with a large amount of demand response resources are drawing more and more widespread attention. In order to fully exploit the IDR potential of residential users and analyse the influence of user comfort and consumer psychology (UCCP) on IDR, the optimised operation study of load aggregator (LA) based on UCCP‐IDR model is proposed. Firstly, a self‐organising map algorithm for clustering is introduced, from which various types of users with differentiated consumption psychology are obtained. Secondly, user comfort and consumption psychology are taken into account to establish a user curtailable, shiftable and transformable load model. Thirdly, the user IDR optimisation model is established based on the load model considering the user response uncertainty. Finally, based on the optimisation strategy of user IDR, the total energy demand of LA is obtained, and thus the optimal operation model of LA equipment is established. The analysis shows that the proposed strategy can provide a more reliable and targeted integrated demand response strategy for residential users, and achieve a win–win situation for both LA and residential users.
Optimal coordination of unbalanced power distribution systems with integrated photovoltaic systems and semi‐fast electric vehicles charging stations
Authors: Alabri Waleed , Jayaweera Dilan
Published: March 2022

Increased integration of photovoltaics (PVs) systems and charging stations for electric vehicles (EVs) has led to a substantial increase in the level of voltage unbalance beyond the acceptable limit. Ordinary voltage regulation devices such as on‐load tap changers (OLTCs) and distribution static synchronous compensator (DSTATCOM) are sometimes incapable of adequately addressing this issue without proper coordination with PVs and EVs. This paper presents a novel real‐time optimal coordination scheme to determine the tap position of OLTC, the amount of reactive power to be exchanged by DSTATCOM and a PV inverter, and the phase connection of EVs. The proposed scheme aims to maintain the voltage magnitude and voltage unbalance within the statutory limit while minimising the power losses in an active unbalanced power distribution system. Advanced and hybrid particle swarm optimisation (AHPSO) algorithm is also developed to solve the optimisation problem, and its robustness in comparison with other techniques is verified. The impact of uncoordinated voltage control and proposed control on voltage unbalance and power losses are investigated. Time‐series simulations confirm the significance and scalability of the developed coordination control scheme on IEEE 37‐node and IEEE 123‐node test feeders with real data and different PV penetration levels.
A global view of shocked plasma in the supernova remnant Puppis A provided by SRG/eROSITA
Authors: Mayer Martin G. F. , Becker Werner , Predehl Peter , Sasaki Manami , Freyberg Michael
Published: March 2022

Context. Puppis A is a medium-age supernova remnant (SNR), which is visible as a very bright extended X-ray source. While numerous studies have investigated individual features of the SNR, at this time, no comprehensive study of the entirety of its X-ray emission exists.

Aims. Using field-scan data acquired by the SRG/eROSITA telescope during its calibration and performance verification phase, we aim to investigate the physical conditions of shocked plasma and the distribution of elements throughout Puppis A. In doing so, we take advantage of the uniform target coverage, excellent statistics, and decent spatial and spectral resolution of our data set.

Methods. Using broad- and narrow-band imaging, we investigate the large-scale distribution of absorption and the plasma temperature as well as that of typical emission lines. This approach is complemented by a spatially resolved spectral analysis of the shocked plasma in Puppis A, for which we divided the SNR into around 700 distinct regions, resulting in maps of key physical quantities over its extent.

Results. We find a strong peak of foreground absorption in the southwest quadrant, which in conjunction with high temperatures at the northeast rim creates the well-known strip of hard emission crossing Puppis A. Furthermore, using the observed distribution of ionization ages, we attempt to reconstruct the age of the shock in the individual regions. We find a rather recent shock interaction for the prominent northeast filament and ejecta knot, as well as for the outer edge of the bright eastern knot. Finally, elemental abundance maps reveal only a single clear enhancement of the plasma with ejecta material, consistent with a previously identified region, and no obvious ejecta enrichment in the remainder of the SNR. Within this region, we confirm the spatial separation of silicon-rich ejecta from those dominated by lighter elements. The apparent elemental composition of this ejecta-rich region would imply an unrealistically large silicon-to-oxygen ratio when compared to the integrated yield of a core-collapse supernova. In reality, both the observed ejecta composition and their apparent distribution may be biased by the unknown location and strength of the reverse shock.
Spatially resolved mass–metallicity relation at z  ∼  0.26 from the MUSE-Wide Survey
Authors: Yao Yao , Chen Guangwen , Liu Haiyang , Chen Xinkai , Lin Zesen , Zhang Hong-Xin , Gao Yulong , Kong Xu
Published: March 2022

Aims. Galaxies in the local universe have a spatially resolved star-forming main sequence (rSFMS) and mass–metallicity relation (rMZR). We know that the global mass–metallicity relation (MZR) results from the integral of the rMZR, and it evolves with redshift. However, the evolution of the rMZR with redshift is still unclear because the spatial resolution and signal-to-noise ratio are low. Currently, too few observations beyond the local universe are available, and only simulations can reproduce the evolution of the rMZR with redshift.

Methods. We selected ten emission-line galaxies with an average redshift of z ∼ 0.26 from the MUSE-Wide DR1. We obtained the spatially resolved star formation rate (SFR) and metallicity from integral field spectroscopy (IFS), as well as the stellar mass surface density from 3D-HST photometry. We derived the rSFMS and rMZR at z ∼ 0.26 and compared them with those of local galaxies.

Results. We find that the rSFMS of galaxies at z ∼ 0.26 has a slope of ∼0.771. The rMZR exists at z ∼ 0.26, showing a similar shape to that of the local universe, but a lower average metallicity that is about ∼0.11 dex lower than the local metallicity. In addition, we also study the spatially resolved fundamental metallicity relation (rFMR) of these galaxies. However, there is no obvious evidence that an rFMR exists at z ∼ 0.26, and it is not an extension of rMZR at a high SFR.

Conclusions. Similar to their global versions, the rSFMS and rMZR of galaxies also evolve with redshift. At fixed stellar mass, galaxies at higher redshift show a higher SFR and lower metallicity. These suggest that the evolution of the global galaxy properties with redshift may result from integrating the evolution of the spatially resolved galaxy properties.
Treatment of Children Trichobezoar a Retrospective Study of 11
Cases
Authors: HanBin Zhao , Chunjiang Yang , Yi Wang
Published: March 2022

Purpose The goal of this study to summarize the clinical features,
treatment and prognosis of children trichobezoar, and to guide the clinical
diagnosis and treatment.

Methods The clinical manifestations, auxiliary examination results,
diagnosis and treatment process and family relationship of 11 cases of children
with trichobezoar in our hospital were analyzed retrospectively.

Results 11 cases were female, 4 cases were divorced single parent family,
and 2 case was left behind child. Six patients were admitted to hospital with
sudden exacerbation of chronic abdominal pain, and four of them had recurrent
vomiting. Five patients were admitted to hospital with acute abdominal pain, and
3 of them had vomiting symptoms; The weight of 1 case was lower than
−2 SD, 4 cases were between −2 SD ~
−1 SD. 6 cases had palpable left upper abdominal mass with mild
tenderness, 1 case only had left upper abdominal tenderness, 4 cases had no
positive abdominal signs; The results of color Doppler ultrasonography in 8
children indicated the strong echo mass in the stomach, and 3 of them showed
that the hyperechoic group extended to duodenum through pylorus. 7 cases had a
tail end extending into the small intestine after removing the gastrolith during
the operation. Four cases were found with jejunal perforation, 2 cases were
treated with intestinal resection and anastomosis, and 2 cases were treated with
intestinal repair. All the children were improved and discharged after
operation.

Conclusion For single parent families or left behind children with a
history of chronic abdominal pain, vomiting and trichophilia, gastric hair
stones should be highly suspected. For large hair stones in the stomach, they
should be removed surgically. During the operation, the small intestine should
be explored routinely to prevent the missed diagnosis of small intestinal
perforation. Psychological guidance should be given to the children and their
parents to prevent recurrence.
Family Structure is Associated with Mental Health and Attention
Deficit (Hyperactivity) Disorders in Adolescents with Type 1
Diabetes
Authors: Baechle Christina , Stahl-Pehe Anna , Castillo Katty , Holl Reinhard W. , Rosenbauer Joachim
Published: March 2022

Objective To analyze the cross-sectional associations of family structure
with mental health and attention deficit (hyperactivity) disorders (AD(H)D) in
11- to 17-year-old adolescents with early-onset type 1 diabetes participating in
one of three baseline surveys as part of an ongoing cohort study.

Methods Parents (n=1,631) completed the Strengths and Difficulties
Questionnaire to screen for their child’s mental health and answered
questions about their child’s diagnosis of AD(H)D. Associations between
mental health or AD(H)D and family structure were analyzed using multivariable
logistic regression analyses adjusted for various personal and diabetes-related
variables.

Results Compared to adolescents living with both parents, adolescents
living with one parent and his/her partner had 2.35 (95%
confidence interval 1.32; 4.21) higher odds of abnormal screening result and
2.08 (1.09; 3.95) higher odds of a borderline screening result while adolescents
living with a single parent had 1.84 (1.07; 3.17)/1.08 (0.53; 2.21)
higher odds of abnormal/borderline screening results. The odds ratios
for diagnosed attention deficit (hyperactivity) disorder were 2.17 (0.98; 4.84)
for adolescents living with one parent and his/her partner and 1.27
(0.54; 3.01) for those living with a single parent vs. both parents.

Conclusions Our results indicate higher odds of mental health problems and
AD(H)D in adolescents with type 1 diabetes who do not live with both parents;
this finding was most pronounced in individuals living with one parent and
his/her partner vs. both parents. Longitudinal studies are needed to
verify our results and elucidate the underlying mechanisms.
Es geht um mehr als nur Funktion – Betätigungszentrierung in der orthopädischen Reha
Authors: Cölle Doreen
Published: March 2022

Die funktionelle Struktur der orthopädischen Reha fordert Ergotherapeut*innen heraus, die die Klienten- und Betätigungszentrierung in den Mittelpunkt ihres Handelns stellen. Doreen Cölle zeigt, wie dies gelingen kann.
Adjustment of Anti-Hyperglycaemic Agents During Bowel Preparation for
Colonoscopy in Patients with Diabetes
Authors: Müssig Karsten , Adamek Henning E.
Published: March 2022

Objective Due to the growing diabetes pandemic, the number of
colonoscopies performed in patients with diabetes is steadily rising. However,
recommendations on adjustments of anti-hyperglycaemic agents (AHG) during bowel
preparation for colonoscopy are limited.

Methods A total of nine articles were revealed on a PubMed search using
the search terms “diabetes” and “colonoscopy”,
“sigmoidoscopy”, “endoscopy”,
“endoscopic intervention”, “endoscopic invasive
diagnostics”, “endoscopic surgery”, or “diabetes
care in the hospital” and manual screening of the references of the
articles reporting on AHG adjustment during bowel preparation.

Results Regular glucose measurements and the opportunity to contact the
diabetes team were commonly advised. Recommendations also agreed that all oral
AHG and short-acting insulin should be omitted when patients are on clear
fluids. Recent studies suggest discontinuation of sodium-glucose cotransporter-2
(SGLT2) inhibitors even three days before the colonoscopy. In contrast,
recommendations differed regarding adjustment of basal insulin depending on
diabetes type and time point in relation to the intervention.

Conclusions While discontinuation of oral AHG and short-acting insulin
during bowel preparation for colonoscopy is generally accepted, recommendations
on the adaptation of basal insulin follow different approaches.
Celecoxib has Preventive and Therapeutic Benefits against Nephrotoxicity Caused by Gentamicin in Mice
Authors: Abd-Eldayem Ahmed M. , Dahpy Marwa A. , Badary Dalia M. , Alnasser Sulaiman Mohammed , Hareedy Mohammad Salem
Published: March 2022

It’s crucial to comprehend the impact of oxidative stress and pro-inflammatory cytokines in the gentamicin-induced kidney injury mechanism. Celecoxib was administered orally either before or after intraperitoneal therapy with gentamicin in mice. The serum levels of creatinine (SCr), blood urea nitrogen (BUN), IL-6, and TNF-α were measured by ELISA test, as well as the levels of the kidney tissue malondialdehyde (MDA), and glutathione (GSH) were also estimated spectrophotometrically. The renal expression of nuclear factor-κB (NF-κB), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and cyclooxygenase 2 (COX-2) mRNAs were evaluated by qPCR. Histopathological evaluation and Immunohistochemical examination of kidney NF-κB, IL-6, and COX-2 were also, performed. Celecoxib successfully prevented gentamicin-induced kidney damage as indicated by reducing blood BUN, SCr, and tissue MDA levels and increasing renal tissue GSH levels as well as lowering the blood IL-6 and TNF-α in comparison to mice received gentamicin. Furthermore, celecoxib has inhibited COX-2, NF-κB, IL-6, and TNF-α expression in the renal tissue. It is noteworthy that celecoxib therapy after gentamicin administration brought about substantially the same results as celecoxib treatment before gentamicin injection in mice. Our results showed the role of celecoxib as a therapeutic tool for gentamicin-induced nephrotoxicity as well as raised its beneficial prophylactic role in this medical challenge by attenuating oxidative stress and inflammation.
Cigarette Smoking Increases the Risk of Type 2 Diabetes Mellitus in
Patients with Non-Alcoholic Fatty Liver Disease: A Population-Based Cohort
Study
Authors: Liu Chan , Wu Yanqin , Duan Wenjuan , Xu Wenming
Published: March 2022

Objective Cigarette smoke and non-alcoholic fatty liver disease are risk
factors for type 2 diabetes mellitus. However, the impact of smoking on diabetes
risk among patients with non-alcoholic fatty liver disease remains unclear.

Methods This study included 15,464 Japanese individuals. We defined
non-alcoholic fatty liver disease based on abdominal ultrasound findings where
excess alcohol intake and other liver diseases were excluded. We used Cox
proportional regression analysis to identify risk factors for type 2 diabetes
onset.

Results During 16,446 person-years of follow-up, 223 of 2,714
non-alcoholic fatty liver disease patients developed type 2 diabetes; the
cumulative incidence rate of type 2 diabetes was 13.6 per 1,000 person-years.
The proportions of never, former, and current smokers (self-report) were
35.3%, 31.1%, and 33.6%, and 88.5%,
5.1%, and 6.4% in men and women, respectively. In a Cox
regression model adjusted for sex, age, body mass index, waist circumference,
alcohol intake, exercise, and alanine aminotransferase, aspartate
aminotransferase, gamma-glutamyl transferase, lipid profiles, and blood pressure
values, relative to never smokers, current smokers with non-alcoholic fatty
liver disease had an increased risk of type 2 diabetes (hazard
ratio=2.05; 95% confidence interval: 1.43–2.94). In
addition, former smoking affected the risk of type 2 diabetes; however, this
effect was not statistically significant.

Conclusions This longitudinal study showed that current smoking may act as
a “second hit” and increase the risk of type 2 diabetes in
patients with non-alcoholic fatty liver disease.
Bilateral En-Block Horseshoe Kidney Laparoscopic Nephrectomy
Authors: Fernandez Nicolas , Rickard Mandy , Escobar Rebeca , Farhat Walid
Published: March 2022

Horseshoe kidney (HSK) has a prevalence of 1 in every 500 individuals. The management of patients with HSK is usually conservative, except in the presence of symptoms such as obstruction, stones, glomerulopathies, and tumors. In the following case report, we describe how a bilateral en-block transmesenteric laparoscopic nephrectomy in supine position was performed.

A 5-year-old boy, with proximal hypospadias and early onset of chronic kidney disease due to focal segmental glomerulosclerosis on biopsy, underwent a genetic molecular evaluation that confirmed a pathogenic mutation at the WT-1 gene. Due to the increased risk of developing Wilms tumor, he underwent a bilateral transmesenteric nephrectomy.

In a five-minute video, we describe how we performed an en-block transperitoneal and transmesenteric laparoscopic nephrectomy with special attention to patient positioning, including the feasibility of performing the dissection of the left renal hilum and isthmus with the patient in supine with no need for repositioning, and then moving to the dissection of the right renal hilum and completion of the procedure.

The case herein reported enables us to describe the technical key-points to perform a bilateral en-block laparoscopic nephrectomy with shorter operative time and reduction of blood loss by preserving the entire specimen, without the need for an isthmus transection.
Synthesis and Biological Evaluation of a Series of Novel 1-(3-((6-Fluoropyridin-3-yl)oxy)propyl)piperazines as Dopamine/Serotonin Receptor Agonists
Authors: Du Xin-Li , Ni Yan-Na , Ji Jiang-Rong , Wan Ze-Hong , Hu Zhi-Jing , Ge Yu-Qiang , Li Jian-Qi , Wang Guan
Published: March 2022

Evidence suggested that the use of partial dopamine D2/D3 receptor agonists may be a better choice for the treatment of Parkinson's disease (PD), and the stimulation of 5-HT1A receptors (mainly via nondopaminergic mechanisms) alleviates motor and nonmotor disorders of PD, implying that the multitarget approach may provide a double bonus for the treatment of the disease. In this study, 20 novel 1-(3-((6-fluoropyridin-3-yl)oxy)propyl)piperazine derivatives were designed and synthesized using a bioisosterism approach, and their activities for D2/D3/5-HT1A receptors were further tested. The results showed that several compounds exhibited a multitarget combination of D2/5-HT1A agonism. Compounds 7b and 34c showed agonistic activities on D2/D3/5-HT1A receptor. The EC50 value of 7b for D2/D3/5-HT1A receptor were 0.9/19/2.3 nmol/L, respectively; and the EC50 value of 34c for D2/D3/5-HT1A receptor were 3.3/10/1.4 nmol/L, respectively. In addition, 34c exhibited good metabolic stability (the half-life T
1/2 = 159.7 minutes) in vitro, which is of great significance for the further exploration of multitarget anti-PD drugs.
Outcomes of the bionic semicircular canals support the “density hypothesis” and “circular hypothesis”
Authors: Jiang Yani , Qin Yongbin , Lu Shien , Wang Zhi , Li Qiang , Bian Yixiang
Published: March 2022

To date, there are three main hypotheses explaining why the human semicircular canals (HSCCs) cannot sense linear accelerations. To further study this issue, we designed a bionic ampulla (BA) instrumented with a symmetrical metal core polyvinylidene fluoride fiber as a bionic sensor, which imitates the structure and function of the human ampulla. The BA was confirmed to have a good sensing ability in experiments with a straight tube. Additionally, we designed a bionic semicircular canal model, a blocking model, and a square model. We compared the perception performance of these three models to test the “density hypothesis,” the “closed loop hypothesis,” and the “circular hypothesis.” The outcomes of these experiments verified the “density hypothesis” and “circular hypothesis,” but did not support the “closed loop hypothesis,” shedding light on why the HSCC is sensitive to angular acceleration, but not to linear acceleration.
Determination of best particle tracking velocimetry method for two-dimensional dusty plasmas
Authors: Zeng Yue , Ma Zhuang , Feng Yan
Published: March 2022

A practical procedure of determining the best choice of particle tracking velocimetry (PTV) methods for the analysis of two-dimensional (2D) dusty plasmas is provided. Using the measured particle positions with errors, the algorithm of PTV introduces further systematic errors while calculating particle velocities. To better quantify the errors, computer simulations of 2D Yukawa liquids are performed so that the true particle positions and velocities are precisely known. Synthetic data are achieved by varying the time interval between frames and adding the uncertainty with the different magnitude to the particle position data. Various PTV methods are used to calculate the velocity data from the achieved synthetic data, and the obtained velocity data from these PTV methods are compared with the true velocity data using two diagnostics to determine the best PTV method for various conditions. The results of various PTV methods with the simulation data are further confirmed by the demonstration using the 2D dusty plasma experimental data. This practical procedure is also applicable to determine the best PTV method for dusty plasmas in different conditions, such as those in Tokamaks, and for other physical systems, including colloids, granular materials, and fluid mechanics.
High-speed spatial light modulation based on photon dimension mapping assisted by an integrated mode multiplexer
Authors: Liu Jun , Zheng Shuang , Chen Shi , Zhu Long , Li Shimao , Gao Shengqian , Tan Heyun , Cai Xinlun , Wang Jian
Published: March 2022

Photon dimension mapping provides an efficient way to learn from each other's strengths to offset their own weaknesses in a variety of applications. By mapping the conventional amplitude modulation to spatial mode modulation and employing an integrated orbital angular momentum (OAM) mode multiplexer, we present an integrated approach to break the spatial light modulation speed limit and implement the high-speed silicon-chip-assisted OAM encoding information transfer. The silicon chip is formed by a multi-mode micro-ring resonator with angular grating embedded in the inner wall and two bus waveguides with different widths for OAM mode multiplexing. Using the fabricated silicon-based OAM mode multiplexer (OAM+1 and OAM-14), we demonstrate 15-Gbit/s amplitude-to-OAM modulation mapping in the experiment, which is far beyond the achievable low-speed OAM encoding information transfer with a conventional spatial light modulator (SLM). The observed optical signal-to-noise ratio (OSNR) penalties at a bit-error rate (BER) of 2 × 10−3 are about 1.0 dB, and the OSNR penalty is improved by about 1.4 dB with the balanced detection. The demonstrations with favorable performance may open up added opportunities in more spatial-mode-enabled applications by photon dimension mapping with silicon chips.
The equation of state and shock-driven decomposition of polymethylmethacrylate (PMMA)
Authors: Coe Joshua D. , Lentz Meghan , Velizhanin Kirill A. , Gammel J. Tinka , Kaushagen John , Jones Keith , Cochrane Kyle R.
Published: March 2022

We present new equations of state (EOS) for polymethylmethacrylate and its shock-driven decomposition products, generated in both tabular form and as linear US−up fits to all previously available shock data. Different approaches are taken for materials shocked above and below the apparent threshold for chemical reactions at pressures P≈30 GPa. Both EOSs are calibrated to and compared with a broad array of experimental results, as well as new ab initio molecular dynamics simulations presented here. Comparisons are good in most cases, and we focus our particular attention on those observables that test the distinction between reactants and products.
Discussion of a new mechanical model for interpenetrating phase composites under compression considering constituent phase interactions
Authors: Wang Xiaoxing , Zhou Yu , Li Jingli , Li Huijian , Liang Xi
Published: March 2022

Interpenetrating phase composites (IPCs) are a new type of materials with designable mechanical properties. In this work, to explore a simple, applicable, and accurate method for property designability of interpenetrated phase composites, the interaction between the matrix phase and the reinforcing phase of IPC under compressive stress is discussed, and a microstructured representative volume element is proposed for interpenetrating metal/polymer composites under compressive loading by considering the interaction of constituent phases. The stress–strain relationship of the representative volume element is established based on the iso-stress and iso-strain assumptions. Compared with the experimental results with those of interpenetrated metal/polymer composites, interpenetrated metal/metal composites, and interpenetrated metal/ceramic composites, it is shown that the analytical solutions can accurately predict the elasto-plastic compressive stress–strain curves.
Periodic motions and homoclinic orbits in a discontinuous dynamical system on a single domain with multiple vector fields
Authors: Guo Siyu , Luo Albert C. J.
Published: March 2022

In this paper, periodic motions and homoclinic orbits in a discontinuous dynamical system on a single domain with two vector fields are discussed. Constructing periodic motions and homoclinic orbits in discontinuous dynamical systems is very significant in mathematics and engineering applications, and how to construct periodic motions and homoclinic orbits is a central issue in discontinuous dynamical systems. Herein, how to construct periodic motions and homoclinic orbits is presented through studying a simple discontinuous dynamical system on a domain confined by two prescribed energies. The simple discontinuous dynamical system has energy-increasing and energy-decreasing vector fields. Based on the two vector fields and the corresponding switching rules, periodic motions and homoclinic orbits in such a simple discontinuous dynamical system are studied. The analytical conditions of bouncing, grazing, and sliding motions at the two energy boundaries are presented first. Periodic motions and homoclinic orbits in such a discontinuous dynamical system are determined through the specific mapping structures, and the corresponding stability is also presented. Numerical illustrations of periodic motions and homoclinic orbits are given for constructed complex motions. Through this study, using discontinuous dynamical systems, one can construct specific complex motions for engineering applications, and the corresponding mathematical methods and computational strategies can be developed.
A high-Q mid-infrared Tamm plasmon absorber using MgF2 and Ge aperiodic tandem films designed by the genetic algorithm
Authors: Ou Chunhui , Wang Jian , Sun Changzheng , Hao Zhibiao , Han Yanjun , Xiong Bing , Wang Lai , Li Hongtao , Yu Jiadong , Luo Yi
Published: March 2022

A high-Q mid-infrared Tamm plasmon (TP) absorber using MgF2 and Ge aperiodic tandem films is designed by the genetic algorithm and fabricated by electron beam evaporation and magnetron sputtering. Such a design circumvents the need for the distributed Bragg reflector grating, and the thickness of individual MgF2 films is much smaller than a quarter of wavelength in films (λ/4n). The fabricated TP absorber exhibits a high and sharp absorption peak at 2.73 μm with a quality factor (Q) of 144, while the simulated counterpart has the absorption peak at 2.72 μm with a Q of 155. The profiles of an electromagnetic field in the tandem films are also simulated to reveal the mechanism of narrow thermal emission. Such a high-Q TP absorber is very promising in the mid-infrared simulator and detection.
Raman spectroscopy study of the slow order–order transformation of deuterium atoms: Ice XIX decay and ice XV formation
Authors: Thoeny Alexander V. , Parrichini Iside S. , Gasser Tobias M. , Loerting Thomas
Published: March 2022

The nature of the hydrogen substructure of a deuterated and deuterium chloride (DCI)-doped ice VI sample after cooling at 1.8 GPa has been a topic of recent interest—especially because the novel ice polymorph ice XIX was discovered in the course of such studies. We here investigate deuterated samples containing 5% H2O using Raman spectroscopy to probe for transitions associated with rearrangement of D-atoms in ice XIX. The protocol involving heating at subambient pressure (10 mbar) in this study follows closely the one used in our earlier neutron diffraction study. Heating of ice XIX induces a complex cascade of processes involving both ordering and disordering of D atoms. Our Raman spectra demonstrate that the transition sequence is ice XIX → ice VI‡ → ice XV, in accordance with our earlier neutron diffraction result. First signs for ice XIX decay are evident at 100 K, while ice XV build-up is seen only at 108 K and above. Between 100 and 108 K, a transiently disordered D-substructure appears, where at 108 K, ice VI‡ forms from ice XIX and simultaneously decays to produce ice XV—thereby establishing a dynamic equilibrium. Using isothermal, time-resolved Raman spectroscopy in real time, we here determine rate constants, Avrami exponents, and activation energies for both slow processes, ice XIX decay and ice XV build-up. The first transition in this sequence, ice XIX decay, is faster than the second transition, ice XV build-up, so that ice VI‡ accumulates. On the basis of the Johnson–Mehl–Avrami–Kolmogorov data obtained from the isothermal Raman experiment, we additionally report kinetic models for the development of fractions of ices XIX, XV, and VI‡ in non-isothermal heating experiments at different heating rates. These models consider the two coupled first-order transitions as separated processes, where the phase fractions are calculated for incrementally small temperature (or time) steps. These models compare favorably with our previous observations for slowly or rapidly heated ice XIX samples, such as in calorimetry or neutron diffraction experiments.
Elevated temperature spectroscopic ellipsometry analysis of the dielectric function, exciton, band-to-band transition, and high-frequency dielectric constant properties for single-crystal ZnGa2O4
Authors: Hilfiker Matthew , Williams Emma , Kilic Ufuk , Traouli Yousra , Koeppe Nate , Rivera Jose , Abakar Assya , Stokey Megan , Korlacki Rafał , Galazka Zbigniew , Irmscher Klaus , Schubert Mathias
Published: March 2022

We report the elevated temperature (22 °C ≤ T ≤ 600 °C) dielectric function properties of melt grown single crystal ZnGa2O4 using a spectroscopic ellipsometry approach. A temperature dependent Cauchy dispersion analysis was applied across the transparent spectrum to determine the high-frequency index of refraction yielding a temperature dependent slope of 3.885(2) × 10−5 K−1. A model dielectric function critical point analysis was applied to examine the dielectric function and critical point transitions for each temperature. The lowest energy M0-type critical point associated with the direct bandgap transition in ZnGa2O4 is shown to red-shift linearly as the temperature is increased with a subsequent slope of −0.72(4) meV K−1. Furthermore, increasing the temperature results in a reduction of the excitonic amplitude and increase in the exciton broadening akin to exciton evaporation and lifetime shortening. This matches current theoretical understanding of excitonic behavior and critically provides justification for an anharmonic broadened Lorentz oscillator to be applied for model analysis of excitonic contributions.
Pressure effect on structure transition and optical anisotropy in MoO3
Authors: Xie Shiyu , Cheng Xuerui , Hu Chuansheng , Zhang Zhenghao , Zhang Huanyu , Liu Hengjie , Qi Zeming
Published: March 2022

We investigated the phase transition and anisotropic optical property of MoO3 under pressure by optical spectroscopy. An α-MoO3 to MoO3-II transition and another MoO3-II to MoO3-III transition were observed at 11 and at 27 GPa, respectively. Accompanied by the structural transition, its optical anisotropy also changes with pressure. While maintaining the similar angle-resolved intensity patterns, the polarization angle with the maximum intensity of the Mo–O2–Mo symmetric stretching mode moves from 90° to 105° then back to 90° with pressure. The result is helpful to understand the mechanism of the pressure-induced phase transition and tune the anisotropic optical properties of MoO3.
Variability in pyrogenic carbon properties generated by different burning temperatures and peatland plant litters: implication for identifying fire intensity and fuel types
Authors: Gao Chuanyu , Cong Jinxin , Sun Yang , Han Dongxue , Wang Guoping
Published: March 2022

Pyrogenic carbon (PyC), generated by fire, acts as a stable carbon deposit in natural ecosystems and is widely used to reconstruct fire history. Fuel type and burning temperature are the two major factors that influence PyC properties and exert variable effects on soil carbon pools, especially for peatlands. However, whether analysis of PyC can identify these two factors remains unclear. To address this knowledge gap, we selected typical peatland plant litters of seven shrub and seven herb plants in the Great Khingan Mountains, China. The properties of PyC produced at 250°C (low-intensity burning) and 600°C (high-intensity burning) without oxygen were evaluated. The results showed that the effects of burning temperature and plant type on δ13C-PyC were not significant. The differences in the initial compositions of herbs and shrubs led to more aromatic and carboxylic compounds in shrub PyC than in herb PyC. A high burning temperature led to less labile components (e.g. aliphatic compounds and acids) and higher thermal stability of high-temperature PyC compared to that of low-temperature PyC. Our results also indicate that several typical PyC chemical composition indicators (e.g. Fourier-transform infrared spectroscopy 1515/1050 ratio and 1720/1050 ratio) can potentially identify PyC sources.
Cryo-EM structures of staphylococcal IsdB bound to human hemoglobin reveal the process of heme extraction
Authors: De Bei Omar , Marchetti Marialaura , Ronda Luca , Gianquinto Eleonora , Lazzarato Loretta , Chirgadze Dimitri Y. , Hardwick Steven W. , Cooper Lee R. , Spyrakis Francesca , Luisi Ben F. , Campanini Barbara , Bettati Stefano
Published: March 2022

Significance

During infection, the human pathogen
Staphylococcus aureus
expresses a surface-exposed receptor, Iron surface determinant B (IsdB), that captures free human hemoglobin (Hb) and removes heme to retrieve iron, an essential nutrient for bacterial proliferation inside the host. Using single-particle cryo-electron microscopy, we solved the structure of two complexes between Hb and IsdB that represent snapshots of the initial interaction, where heme is still bound to Hb, and the final complex after completion of heme extraction. The structural and dynamic details unlocked through these structures will boost the design of inhibitors of IsdB:Hb interaction that might work as innovative antimicrobials.
Sensitivity ofVHLmutant kidney cancers to HIF2 inhibitors does not require an intact p53 pathway
Authors: Stransky Laura A. , Vigeant Sean M. , Huang Bofu , West Destiny , Denize Thomas , Walton Emily , Signoretti Sabina , Kaelin William G.
Published: March 2022

Significance

VHLtumor suppressor gene inactivation is a hallmark of clear cell renal cell carcinoma (ccRCC), the most common form of kidney cancer, and promotes tumor growth by stabilizing the hypoxia-inducible factor 2 (HIF2) transcription factor. HIF2 inhibitors appear to be helpful for some, but not all, ccRCC patients in clinical trials. Previous preclinical and clinical data suggested that only ccRCCs that can activate the p53 tumor suppressor in response to DNA damage would respond to HIF2 inhibitors. Here, we show that an intact p53 pathway is neither necessary nor sufficient for the sensitivity of ccRCCs to HIF2 inhibitors, suggesting that it would be premature to use p53 status to determine which ccRCC patients should be treated with a HIF2 inhibitor.
Uncovering the crystal defects within aragonite CaCO
3
Authors: San Xingyuan , Gong Mingyu , Wang Jian , Ma Xiuliang , dos Reis Roberto , Smeets Paul J. M. , Dravid Vinayak P. , Hu Xiaobing
Published: March 2022

Significance

Nacre exhibits outstanding mechanical performance, which results from coordinated deformation mechanisms synergistically working in characteristic microstructures at multiple length scales. A comprehensive understanding of crystal defects within aragonite is critical for discussing the deformation behavior of nacre on microstructure at the nanoscale through atomic scale. By integrating aberration-corrected transmission electron microscopy, crystallographic analysis, and theoretical calculations, we reveal various crystal defects within aragonite at atomic scale and discuss their potential effects on deformation. Our work will serve as cornerstones for modeling analysis and in-depth discussions on nanoscale deformation mechanisms within nacre. Additionally, these atomic-scale insights will benefit theoretical evaluation of the environmental effect on defect formation, enabling defect control in synthetic aragonite and designing of stronger and tougher bioengineering materials.
Structural and biochemical insights into lipid transport by VPS13 proteins
Authors: Adlakha Jyoti , Hong Zhouping , Li PeiQi , Reinisch Karin M.
Published: March 2022

VPS13 proteins are proposed to function at contact sites between organelles as bridges for lipids to move directionally and in bulk between organellar membranes. VPS13s are anchored between membranes via interactions with receptors, including both peripheral and integral membrane proteins. Here we present the crystal structure of VPS13s adaptor binding domain (VAB) complexed with a Pro-X-Pro peptide recognition motif present in one such receptor, the integral membrane protein Mcp1p, and show biochemically that other Pro-X-Pro motifs bind the VAB in the same site. We further demonstrate that Mcp1p and another integral membrane protein that interacts directly with human VPS13A, XK, are scramblases. This finding supports an emerging paradigm of a partnership between bulk lipid transport proteins and scramblases. Scramblases can re-equilibrate lipids between membrane leaflets as lipids are removed from or inserted into the cytosolic leaflet of donor and acceptor organelles, respectively, in the course of protein-mediated transport.
The Wald–Zoupas prescription for asymptotic charges at null infinity in general relativity
Authors: Grant Alexander M , Prabhu Kartik , Shehzad Ibrahim
Published: March 2022

We use the formalism developed by Wald and Zoupas to derive explicit covariant expressions for the charges and fluxes associated with the Bondi–Metzner–Sachs symmetries at null infinity in asymptotically flat spacetimes in vacuum general relativity. Our expressions hold in non-stationary regions of null infinity, are local and covariant, conformally-invariant, and are independent of the choice of foliation of null infinity and of the chosen extension of the symmetries away from null infinity. While similar expressions have appeared previously in the literature in Bondi–Sachs coordinates (to which we compare our own), such a choice of coordinates obscures these properties. Our covariant expressions can be used to obtain charge formulae in any choice of coordinates at null infinity. We also include detailed comparisons with other expressions for the charges and fluxes that have appeared in the literature: the Ashtekar–Streubel flux formula, the Komar formulae, and the linkage and twistor charge formulae. Such comparisons are easier to perform using our explicit expressions, instead of those which appear in the original work by Wald and Zoupas.
Influence of crystal structure and oxygen vacancies on optical properties of nanostructured multi-stoichiometric tungsten suboxides
Authors: Višić Bojana , Pirker Luka , Opačić Marko , Milosavljević Ana , Lazarević Nenad , Majaron Boris , Remškar Maja
Published: March 2022

Four distinct tungsten suboxide (WO3–x
) nanomaterials were synthesized via chemical vapour transport reaction and the role of their crystal structures on the optical properties was studied. These materials grow either as thin, quasi-2D crystals with the W
n
O3n-1 formula (in shape of platelets or nanotiles), or as nanowires (W5O14, W18O49). For the quasi-2D materials, the appearance of defect states gives rise to two indirect absorption edges. One is assigned to the regular bandgap occurring between the valence and the conduction band, while the second is a defect-induced band. While the bandgap values of platelets and nanotiles are in the upper range of the reported values for the suboxides, the nanowires’ bandgaps are lower due to the higher number of free charge carriers. Both types of nanowires sustain localized surface plasmon resonances, as evidenced from the extinction measurements, whereas the quasi-2D materials exhibit excitonic transitions. All four materials have photoluminescence emission peaks in the UV region. The interplay of the crystal structure, oxygen vacancies and shape can result in changes in optical behaviour, and the understanding of these effects could enable intentional tuning of selected properties.
Long-wavelength InAs/GaSb superlattice double heterojunction infrared detectors using InPSb/InAs superlattice hole barrier
Authors: Liu Jiafeng , Zhu He , Zhu Hong , Li Meng , Huai Yunlong , Liu Zhen , Huang Yong
Published: March 2022

We demonstrate two double heterojunction long-wavelength infrared detectors based on InAs/GaSb superlattice on InAs substrates grown by metal-organic chemical vapor deposition. In the two structures, the hole barrier employs a novel InPSb/InAs superlattice to achieve conduction-band alignment, while the electron barrier is InAs/GaSb superlattice to achieve valence-band alignment. Two devices with n-type absorber layer and p-type absorber layer exhibit cut-off wavelengths of ∼10.4 μm and ∼12.2 μm, dark current densities of 9 × 10−4 A cm−2 and 2 × 10−2 A cm−2, and specific detectivities of ∼1.7 × 1010 cm Hz1/2 W−1 and ∼1.5 × 1010 cm Hz1/2 W−1, respectively. The device with n-type absorber has a lower dark current due to the natural valence-band alignment, but it has a low quantum efficiency (QE) resulting from the use of n-type absorber layer. In contrast, the device with p-type absorber has a higher dark current that can be possibly attributed to the conduction-band misalignment, but it achieves a higher QE due to the benefits from the p-type absorber.
Investigation of ambient temperature and thermal contact resistance induced self-heating effects in nanosheet FET
Authors: Rathore Sunil , Jaisawal Rajeewa Kumar , Suryavanshi Preeti , Kondekar Pravin N
Published: March 2022

Self-heating effect (SHE) is a severe issue in advanced nano-scaled devices such as stacked nanosheet field-effect transistors (NS-FET), which raises the device temperature (T
D), that ultimately affects the key electrical characteristics, i.e. threshold voltage (V
T), DIBL, subthreshold slope (SS), I
OFF, I
ON, etc. SHE puts design constraints in the advanced CMOS logic devices and circuits. In this paper, we thoroughly investigated the impact of ambient temperature and interface thermal contact resistance induced-self heating effect in the NS-FET using extensive numerical simulations. The weak electron–phonon coupling, phonon scattering, and the ambient temperature-induced joule energy directly coupled with thermal contact resistance cause the SHE-induced thermal degradation, which increases the device temperature (T
D) and affects the device reliability. The baseline NS-FET is well-calibrated with the experimental data and 3D quantum corrected drift-diffusion coupled hydrodynamic and thermodynamic transport models is used in our TCAD framework to estimate the impact of ambient temperature and interface thermal contact resistance on the device performance. Moreover, we also evaluate the SHE-induced performance comparison of NS-FET with conventional FinFET and found that thermal degradation in NS-FET potentially worsen the electrical characteristics. Thus, a detailed TCAD analysis shows that the ambient temperature and interface thermal contact resistances deteriorate the effective thermal resistance (R
eff) and device performance metrics.
Electronic structure of rare-earth mononitrides: quasiatomic excitations and semiconducting bands
Authors: Galler Anna , Pourovskii Leonid V
Published: March 2022

The electronic structure of the rare-earth mononitrides LnN (where Ln = rare-earth), which are promising materials for future spintronics applications, is difficult to resolve experimentally due to a strong influence of defects on their transport and optical properties. At the same time, LnN are challenging for theory, since wide semiconducting 2p and 5d bands need to be described simultaneously with strongly correlated 4f states. Here, we calculate the many-body spectral functions and optical gaps of a series of LnN (with Ln = Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er) by a density-functional + dynamical mean-field theory (DFT + DMFT) approach treating the correlated Ln 4f shells within the quasi-atomic Hubbard-I approximation. The on-site Coulomb interaction in the 4f shell is evaluated by a constrained DFT + Hubbard-I approach. Furthermore, to improve the treatment of semiconducting bands in DFT + DMFT, we employ the modified Becke–Johnson semilocal exchange potential. Focusing on the paramagnetic high-temperature phase, we find that all investigated LnN are pd semiconductors with gap values ranging from 1.02 to 2.14 eV along the series. The pd band gap is direct for light Ln = La…Sm and becomes indirect for heavy rare-earths. Despite a pronounced evolution of the Ln 4f states along the series, empty 4f states are invariably found above the bottom of the 5d conduction band. The calculated spectra agree well with those available from x-ray photoemission, x-ray emission and x-ray absorption measurements.
Enforcing Levy relaxation for multi-mode fibers with correlated disorder
Authors: Li Yaxin , Cohen Doron , Kottos Tsampikos
Published: March 2022

Environmental perturbations and noise are source of mode mixing and interferences between the propagating modes of a complex multi-mode fiber (MMF). Typically, they are characterized by their correlation (paraxial) length, and their spectral content which describes the degree of coupling between various modes. We show that an appropriate control of these quantities allows to engineer Levy-type relaxation processes of an initial mode excitation. Our theory, based on random matrix theory modeling, is tested against realistic simulations with MMFs.