bluuebunny/crossref_metadata_2025 huggingface dataset:
Chemodestructive fractionation of humus as an indicator of the functional state of soil organic matter
Authors: Kozlova Alla , Martynova Natalya , Perfiliev Dmitry , Ludwig Ulyana
Published: February 2023

The content, composition, and properties of humus are the most important characteristics that reflect the features of modern soil formation, the genesis and evolution of soils, and their agrogenic transformation. The main criteria for assessing soil fertility are traditionally the content and reserves of organic matter in soils. At the same time, the decrease in soil fertility is associated not so much with a decrease in the total content of humus, but with the loss of its labile forms, which determine the life of the soil, its most important agronomic properties and crop yields. One of the integral indicators characterizing the state and functioning of soil organic matter (SOM) is the ratio of stable and labile forms of organic compounds obtained by chemodestructive analysis. The determination of the bichromate oxidizability of humus showed that the virgin soils of the Southern Cis-Baikal region contain an equal amount of stable and labile forms of organic compounds. Accordingly, the humus in them is a stable and balanced system in relation to external influences. Plowing led to a significant decrease in the easily and hardly hydrolysable humus fractions. In the fallow areas, the upper part of the humus horizon, in terms of the ratio of humus fractions, approaches virgin soils, and the lower part approaches the arable horizons of agricultural soils. The method of permanganate oxidizability of humus revealed a noticeable enrichment in easily oxidizable forms of virgin and, especially, fallow soils of the region. Compared to them, agricultural soils contained noticeably less labile humus, which indicates a sharp decrease in their fertility.
Problems of establishment and activity of the antituberculosis service in Kazakhstan during Virgin Lands campaign (early 1960s)
Authors: Orazbayeva Altaiy , Kozina Valeria , Mazhitova Zhanna , Kurbanova Dina
Published: February 2023

The paper notes that after the formation of the Virgin Lands area in December 1960, the local health authorities faced a pressing issue of solving the problems of tuberculosis spread among the local population, as well as people resettled there. Tuberculosis, like other infectious diseases, was widespread in Kazakhstan. The establishment of tuberculosis dispensaries and the creation of fluorography and X-ray machines have provided an opportunity to expand preventive measures for the examination and detection of tuberculosis patients. The health authorities of the Virgin Lands area considered work in this direction as improving the quality of medical care. However, the quality of treatment was often reduced due to the facts that the treatment regimen was violated in several dispensaries, there were not enough specialists, control over the full and long-term treatment of tuberculosis patients was not imposed. The authors of the paper concluded that insufficient and not universal organization of medical care was one of the reasons for the high incidence of tuberculosis among the population.
Challenges of environmental security in regional policy (on the example of the Lipetsk region)
Authors: Skiperskikh Aleksander
Published: February 2023

This article deals with how environmental problems within a separate subject of the Russian Federation are associated with the legitimacy of regional political power. The case of the Lipetsk region is taken as an example. The economic profile of the region includes a combination of a number of large enterprises and agricultural holdings. Enterprises are represented in cities, while agricultural holdings are represented in rural provinces. But all of them are potential sources of environmental problems. Using the case study method and the comparative method, the author tries to study the extent to which the regional administration controls the challenges of economic security. The author highlights a number of environmental problems and shows how they could be consistently updated during the reign of 3 governors of the Lipetsk region - Mikhail Narolin, Oleg Korolev and Igor Artamonov. Referring to the materials of a number of Russian researchers, the author shows how unique the case of the Lipetsk region can be. The situation in the Lipetsk region is compared with the experience of other regions, where major environmental problems were actualized, which contributed to the formation of the protest agenda.
Low latitude monthly total electron content composite correlations
Authors: Allen Douglas R. , Hodyss Daniel , Forsythe Victoriya V. , McDonald Sarah E.
Published: February 2023

Spatial correlations of total electron content (TEC) variability are compared among two SAMI3 model runs and Jet Propulsion Laboratory Global Ionospheric Maps (JPL/GIM). Individual monthly correlation maps are constructed with Equatorial reference points at 12 evenly spaced longitudes and 12 universal times. TEC composite correlations (TCCs) are then calculated by averaging the individual maps, shifted zonally to synchronize local time. The TCC structures are quantified using Gaussian fits in the zonal and meridional directions. A non-zero large-scale “base correlation” is found in all three datasets for 2014, a year with high solar activity. Higher base correlations generally occur in the SAMI3 runs than in JPL/GIM. The SAMI3 run driven with climatological neutral fields shows higher correlations than the run driven with neutrals from a Whole Atmosphere Community Climate Model with thermosphere–ionosphere eXtension (WACCM-X) simulation. Base correlation values strongly correlate with monthly F10.7 standard deviations. Empirical orthogonal function (EOF) analyses confirm that large-scale correlations are usually, although not always, related to solar forcing. Strong correlations between the Ap index and EOF modes are also observed, consistent with the geomagnetic forcing of the TEC field. The widths of the correlation structures are also examined, and these vary considerably with local time, month, and dataset. Off-Equator conjugate point correlations are also calculated from each dataset and variations with the month and local time are analyzed. Analysis of TCCs for 2010, a year with low solar activity, shows that base correlations as well as correlations of the first EOF mode with F10.7 are generally weaker than in 2014.
Impact of COVID-19 Related Restrictions on Infections in Children
with Cancer or after Hematopoietic SCT
Authors: Hauch Richard , Hinrichs Malena , Ruhwald Rebecca , Schrum Johanna , Rutkowski Stefan , Woessmann Wilhelm , Winkler Beate
Published: February 2023

Background Infections are a major concern for immunocompromised children.
We investigated whether non-pharmaceutical interventions (NPIs) implemented in
the general population during the coronavirus disease 2019 (COVID-19) pandemic
in Germany had an impact on frequency, type and severity of infections in these
patients.

Patients and methods We analyzed all admissions to the clinic of pediatric
hematology, oncology and stem cell transplantation (SCT) with (suspected)
infection or fever of unknown origin (FUO) from 2018 to 2021.

Results We compared a 27-month period before NPIs (Pre-COVID:
01/2018–03/2020; 1041 cases) with a 12-month period with
underlying NPIs (COVID: 04/2020–03/2021; 420 cases).
During the COVID period the number of in-patient stays with FUO or infections
decreased (38,6 cases/month vs. 35,0 cases/month), the median
duration of hospital stays was longer (8 d (CI95: 7–8 d) vs. 9 d (CI95:
8–10 d) P=0,02)), the mean number of antibiotics per case
increased (2,1 (CI95: 2,0–2,2) vs. 2,5 (CI95: 2,3–2,7);
P=0,003)) and a substantial reduction of viral respiratory and
gastrointestinal infections per case was seen (0,24 vs. 0,13; P<0,001).
Notably, there was no detection of respiratory syncytial virus, influenza and
norovirus, between May 2020 and March 2021. Based on need of intensive care
measures and further parameters we conclude that severe (bacterial) infections
were not significantly reduced by NPIs.

Conclusions Introduction of NPIs in the general population during the
COVID-pandemic substantially reduced viral respiratory and gastrointestinal
infections in immunocompromised patients, while severe (bacterial) infections
were not prevented.
Chirurgische Interventionen beim Morbus Paget
Authors: Kurth Andreas
Published: February 2023

Die orthopädisch – chirurgische Behandlung von Patienten mit
einem Morbus Paget stellt eine Herausforderung dar.

In der modernen orthopädischen Chirurgie stehen adäquate
Verfahren zur Verfügung, um – korrekt eingesetzt – dem
Patienten eine deutliche Reduktion seiner Beschwerden zu ermöglichen und
die Lebensqualität zu verbessern. Die Hauptkomplikationen sind
pathologische Frakturen, Deformitäten der befallenen Knochen und die
frühzeitige Entwicklung einer sekundären Arthrose großer
Gelenke.

Für den Operateur zu beachten, dass dieses Patientengut mit einem
erhöhten Risiko für intra- und postoperative Komplikationen
einhergeht. Um die Komplikationsraten weitgehend zu minimieren bedarf es einer
sorgfältigen präoperativen Planung mit
Überprüfung des aktuellen Status der Grunderkrankung und
möglicher präoperativer medikamentöser Intervention
mittels Bisphosphonaten (evidenzbasiert Zoledronat 5 mg) zur
Normalisierung des Knochenstoffwechsels. Auch muss eine umfassende klinische und
radiologische Diagnostik durchgeführt werden, um mögliche
Mitbeteiligungen angrenzender Skelettabschnitte frühzeitig zu erkennen
und Operationen und Implantate planen zu können.

Intraoperativ sind die Schwierigkeiten gekennzeichnet durch die erhöhte
Vaskularisierung des betroffenen Knochens und die deutlich veränderte
Knochenstruktur. Einem vermehrten Blutverlust kann durch eine rechtzeitig
eingeleitete Bisphosphonat-Therapie wahrscheinlich vorgebeugt werden. Wegen des
oft gleichzeitig vorliegenden sklerotischen und osteolytischen Knochens ist die
Verwendung geeigneten Instrumentarien und besondere Sorgfalt bei der
Implantation von Osteosynthesematerial und Endoprothesen geboten. Eine maligne
Entartung sollte bei ausgeprägter Schmerzsymptomatik und
Weichteilschwellung bis zu ihrem Ausschluss in Betracht gezogen werden und eine
weitere Diagnostik eingeleitet werden.
Neue medikamentöse Konzepte bei Patienten mit kolorektalen Karzinomen und Mikrosatelliteninstabilität
Authors: Vangala Deepak , Nilius-Eliliwi Verena
Published: February 2023

Etwa 15% aller Patienten mit kolorektalen Karzinomen zeigen eine hochgradige Mikrosatelliteninstabilität (MSI-high) im Tumorgewebe. Bei ca. ⅓ dieser Patienten liegt die Ursache an
pathogenen Keimbahnvarianten der Mismatch-Reparaturgene, die zu einem Lynch-Syndrom führen. In Kombination mit klinischen Kriterien, wie den Amsterdam- oder revidierten Bethesda-Kriterien,
diente ein MSI-high-Befund bislang vor allem der Identifikation von Risikopatienten. In der modernen Tumortherapie zeigt die Gruppe der MSI-high-Patienten jedoch über nahezu alle
Tumorstadien hinweg Alleinstellungsmerkmale hinsichtlich der medikamentösen Tumortherapie. Nach wie vor gilt, dass MSI-high-Patienten im Stadium UICC II keine adjuvante Chemotherapie
erhalten sollten. Während bei Patienten mit Fernmetastasen und MSI-high-Status Immuncheckpoint-Inhibitoren bereits in der Erstlinie regelhaft und erfolgreich eingesetzt werden, zeigen neue
Daten sowohl bei lokal fortgeschrittenen Kolon- als auch bei Rektumkarzinomen im präoperativen Setting ein tiefes Ansprechen. Gerade für Rektumkarzinompatienten könnte hier ein neues
therapeutisches Verfahren ohne neoadjuvante Chemotherapie und möglicherweise sogar ohne operative Versorgung etabliert werden – bei guter Verträglichkeit und Senkung der Morbidität.
Demzufolge ist die universelle MSI-Testung sowohl zur Identifikation von Risikopatienten als auch zur Therapieplanung bereits heute unerlässlich.
Thyroid Function Abnormalities and Outcomes in Hospitalized Patients
with COVID-19 Infection: A Cross-Sectional Study
Authors: Patel Deepika , Naik Dukhabandhu , Kamalanathan Sadishkumar , Tamilarasu Kadhiravan , Sahoo Jayaprakash , Roy Ayan , Merugu Chandhana , Suryadevara Varun
Published: February 2023

Thyroid gland can be affected by the COVID-19 infection. The pattern of thyroid
function abnormality reported in COVID-19 is variable; in addition, some drugs
used in COVID-19 patients like glucocorticoids and heparin can affect the
thyroid function tests (TFT). We conducted an observational, cross-sectional
study of thyroid function abnormalities with thyroid autoimmune profile in
COVID-19 patients with varying severity from November 2020 to June 2021. Serum
FT4, FT3, TSH, anti-TPO, and anti-Tg antibodies were measured before the
initiation of treatment with steroids and anti-coagulants. A total of 271
COVID-19 patients were included in the study, of which 27 were asymptomatic and
remaining 158, 39, and 47 were classified to mild, moderate and severe
categories, respectively, according to MoHFW, India criteria. Their mean age was
49±17 years and 64.9% were males. Abnormal TFT was present in
37.2% (101/271) patients. Low FT3, low FT4, and low TSH were
present in 21.03%, 15.9% and 4.5% of patients,
respectively. Pattern corresponding to sick euthyroid syndrome was the most
common. Both mean FT3 and FT3/FT4 ratio decreased with increasing
severity of COVID-19 illness (p=0.001). In multivariate analysis, low
FT3 was associated with increased risk of mortality (OR 12.36, 95% CI:
1.23–124.19; p=0.033). Thyroid autoantibodies were positive in
58 (27.14%) patients; but it was not associated with any thyroid
dysfunction. Thyroid function abnormality is common among COVID-19 patients.
Both low FT3 and FT3/FT4 ratio are indicators of disease severity while
low FT3 is a prognostic marker of COVID-19 associated mortality.
Multicenter randomized trial comparing diagnostic sensitivity and cellular abundance with aggressive versus standard biliary brushing for bile duct stenosis without mass syndrome
Authors: Karsenti David , Privat Jocelyn , Charissoux Aurélie , Perrot Bastien , Leblanc Sarah , Chaput Ulriikka , Boytchev Isabelle , Levy Jonathan , Schaefer Marion , Bourgaux Jean-François , Valats Jean-Christophe , Coron Emmanuel , Moreno-Garcia Maira , Vanbiervliet Geoffroy , Rahmi Gabriel , Robles Enrique Perez-Cuadrado , Wallenhorst Timothée
Published: February 2023

Background The diagnosis of cholangiocarcinoma in patients with a biliary stricture without mass syndrome can be obtained by biliary brushing with a sensitivity of ~50 %. We performed a multicenter randomized crossover trial comparing the aggressive Infinity brush with the standard RX Cytology Brush. The aims were to compare sensitivity for cholangiocarcinoma diagnosis and cellularity obtained.

Methods Biliary brushing was performed consecutively with each brush, in a randomized order. Cytological material was studied with blinding to the brush type used and order. The primary end point was sensitivity for cholangiocarcinoma diagnosis; the secondary end point was the abundance of cellularity obtained with each brush, with cellularity quantified in order to determine if one brush strongly outperformed the other.

Results 51 patients were included. Final diagnoses were cholangiocarcinoma (n = 43; 84 %), benign (n = 7; 14 %), and indeterminate (n = 1; 2 %). Sensitivity for cholangiocarcinoma was 79 % (34 /43) for the Infinity brush versus 67 % (29/43) for the RX Cytology Brush (P = 0.10). Cellularity was rich in 31/51 cases (61 %) with the Infinity brush and in 10/51 cases (20 %) with the RX Cytology Brush (P < 0.001). In terms of quantification of cellularity, the Infinity brush strongly outperformed the RX Cytology Brush in 28/51 cases (55 %), while the RX Cytology Brush strongly outperformed the Infinity brush in 4/51 cases (8 %; P < 0.001).

Conclusions This randomized crossover trial showed that the Infinity brush is not significantly more effective than the RX Cytology Brush for biliary stenosis without mass syndrome in terms of sensitivity for cholangiocarcinoma diagnosis, but does offer a significantly higher abundance of cellularity.
Iodine/Sulfinates: Rapid and Convenient Thiolation of Imidazo Heterocycles without Additives
Authors: Redon Sébastien , Vanelle Patrice , Mendes Anne-Sophie
Published: February 2023

An unprecedented I2/sulfinate thiolating system is described for the sulfenylation of electron-rich heterocycles. This phosphine-free strategy permits simple, efficient, and fast sulfenylation of imidazo heterocycles, anilines, indoles, coumarins, or enaminones.
Focality in Febrile Seizures: A Retrospective Assessment Using Arterial Spin Labeling MRI
Authors: Yeom Jung Sook , Kim Young-Soo , Choi Dae-Seob
Published: February 2023

Purpose Defining focality of febrile seizures (FS) in clinical practice remains controversial. We investigated focality issues in FS with a postictal arterial spin labeling (ASL) sequence.

Methods We retrospectively reviewed 77 children (median: 19.0 months, range: 15.0–33.0 months) who consecutively visited our emergency room for FS and underwent brain magnetic resonance imaging (MRI), including the ASL sequence, within 24 hours of seizure onset. ASL data were visually analyzed to assess perfusion changes. Factors related to the perfusion changes were investigated.

Results The mean time to ASL acquisition was 7.0 (interquartile range: 4.0–11.0) hours. The most common seizure classification was unknown-onset seizures (n = 37, 48%), followed by focal-onset (n = 26, 34%) and generalized-onset seizures (n = 14, 18%). Perfusion changes were observed in 43 (57%) patients: most were hypoperfusion (n = 35, 83%). The temporal regions were the most common location of perfusion changes (n = 26, 60%); the majority of these were distributed in the unilateral hemisphere. Perfusion changes were independently associated with seizure classification (focal-onset seizures, adjusted odds ratio [aOR]: 9.6, p = 0.01; unknown-onset seizures aOR: 10.4, p < 0.01), and prolonged seizures (aOR: 3.1, p = 0.04), but not with other factors (age, sex, time to MRI acquisition, previous FS, repeated FS within 24 hour, family history of FS, structural abnormality on MRI, and developmental delay). The focality scale of seizure semiology positively correlated with perfusion changes (R = 0.334, p < 0.01).

Conclusion Focality in FS may be common, and its primary origin might be the temporal regions. ASL can be useful for assessing focality in FS, particularly when seizure onset is unknown.
Dislocation mechanisms of low-temperature plasticity of nanocrystalline titanium: The role of impurity and grain boundary strengthening
Authors: Moskalenko V. A. , Smolianets R. V. , Natsik V. D. , Pohribna Yu. M.
Published: February 2023

The temperature dependences of the yield strength, the strain rate sensitivity of the deforming stress and the activation volume of the process of plastic deformation of nanocrystalline titanium VT1-0 under quasi-static tension in the temperature range 4.2–395 K are found. The nanoscale grain size was obtained using the method of cryomechanical grain fragmentation. A detailed thermal activation analysis of the experimental results was carried out and it was shown that the process of plastic deformation under conditions of ambient and low temperatures is determined by the overcoming of local impurity barriers by dislocations, and grain boundaries are a source of internal stresses. Empirical estimates are obtained for the parameters of the dislocation-impurity interaction. The unambiguous relationship between internal stresses and grain size established for monomodal nanocrystalline titanium made it possible to separate the effects of impurity and grain boundary hardening. The result obtained is an indirect basis for the conclusion about the impossibility of accumulation of dislocations in nanograins during plastic deformation. The decrease in the activation volume for a nanoscale grain at a constant impurity concentration is considered because of the manifestation of the dependence of the diameter of the dislocation loop generated by a grain boundary source on the grain size (confinement effect).
Identical and nonidentical superlattice on the surface of nanotubes: Specific heat and magnetization
Authors: Babanlı A. M.
Published: February 2023

The thermodynamic and magnetic properties of electrons in superlattices on the surface of a nanotube in a longitudinal magnetic field are investigated. It is shown that the specific heat of nondegenerate electron gas in superlattice on the surface of a nanotube oscillates with the change in the magnetic flux. With the increase in effective mass, the magnetization in identical and nonidentical superlattices on the surface of a nanotube are close to each other. Magnetization has a “saw-tooth” form as a function of a magnetic field. For the lattice of nanotubes with two different radii, ordinary compensation points, at which the magnetization vanishes at fixed values of the magnetic field strength, are found.
The relationship between orbital hybridization and superconductivity of sm-doped YBa2Cu3O7–δ studied by x-ray spectroscopy
Authors: Zhao H. H. , Shen J. D. , Wang G. Y. , Jia X. Y. , Mi W. , Liu C. , Wang J. O. , Xu Q. Y. , Li Q.
Published: February 2023

Sm-doped YBa2Cu3O7–δ samples were prepared by conventional solid state reaction method in air. The studies of X-ray photoemission spectroscopy and X-ray absorption spectroscopy indicate that the extra electrons fill the holes in CuO2 planes, so that the hole carrier concentration decrease under Sm substitution. The X-ray absorption spectroscopy of Cu L-edge and O K-edge demonstrates that the hybridization strength between Cu 3d and O 2p decreases with increasing content of Sm, but the hybridization strength between Y 4d, Ba 5d, Sm 4f and O 2p increases with the increasing of Sm content, while the superconductivity of the Sm-doped YBa2Cu3O7–δ samples is suppressed, i.e., the superconducting transition temperature of the samples was lowered. Thus, our experimental results suggest a close relationship between the superconductivity and orbital hybridization.
Effect of irradiation with medium doses of high-energy electrons on the fluctuation conductivity of Y1Ba2Cu3O7–δ single crystals
Authors: Azarenkov N. A. , Khadzhai G. Ya. , Komisarov A. O. , Gevorkyan E. S. , Vovk R. V.
Published: February 2023

The effect of medium doses (from 1019 to 1020 cm–2) of irradiation with fast electrons (energy, E = 2.5 MeV) on the excess conductivity of optimally doped Y1Ba2Cu3O7–δ single crystals has been studied. It is shown that the irradiation with electrons leads to the significant expansion of the temperature interval for the existence of excess conductivity, thereby narrowing the region of the ρ(T) linear dependence in the ab plane in the normal state. It has been established that at doses of 0 ≤ D ≤ 6.5⋅1019 cm–2, the value of the transverse coherence length ξc(0) increases with D by about 3 times and the 2D–3D crossover point shifts in temperature. In contrast to the case of irradiation with low doses (D ≤ 1019 cm–2), irradiation with medium doses leads to a nonmonotonic dependence of the transverse coherence length ξc(0) on the irradiation dose, with a characteristic maximum at D ∼ (7–8)⋅1019 cm–2, which may be related to the general suppression of superconducting characteristics.
Numerical study of the trailing vehicle length on train aerodynamics under crosswind
Authors: Zhu Tianci , Li Wenhui
Published: February 2023

Limited by the wind tunnel size, a one-and-a-half train model is generally adopted during the test to represent the realistic long tandem. Thus, the reasonable arrangement of the trailing vehicle length is of significance for experimental accuracy. In this work, the aerodynamic performance of trains with different trailing vehicle lengths subjected to crosswind was studied using the improved detached eddy simulation method combined with the shear–stress–transport k–ω turbulence model. The 1/8th scaled high-speed trains with five trailing lengths were proposed, and the aerodynamic differences were evaluated at yaw angles ranging from β = 0° to β = 60°. The numerical method was validated by the previous wind tunnel test. Results show that the aerodynamics and flow patterns of the La = 0.50 and the benchmark are highly relevant. The downstream dummy vehicle length has the greatest effect on aerodynamic coefficients at a higher yaw angle (β > 30°), especially at β = 60°, whereas the effects become insignificant at a lower yaw angle (β < 30°). For various La lengths, notable discrepancy appears at the leeward and top side where large vortexes shed off from the roof. The larger contributions to the lateral force and lift force coefficients are mainly due to these areas. A suitable length of La = 0.50 is therefore recommended to obtain more accurate aerodynamics of a long train set.
Energetic preference and topological constraint effects on the formation of DNA twisted toroidal bundles
Authors: Nguyen Nhung T. T. , Ngo Anh T. , Hoang Trinh X.
Published: February 2023

DNA toroids are compact torus-shaped bundles formed by one or multiple DNA molecules being condensed from the solution due to various condensing agents. It has been shown that the DNA toroidal bundles are twisted. However, the global conformations of DNA inside these bundles are still not well understood. In this study, we investigate this issue by solving different models for the toroidal bundles and performing replica-exchange molecular dynamics (REMD) simulations for self-attractive stiff polymers of various chain lengths. We find that a moderate degree of twisting is energetically favorable for toroidal bundles, yielding optimal configurations of lower energies than for other bundles corresponding to spool-like and constant radius of curvature arrangements. The REMD simulations show that the ground states of the stiff polymers are twisted toroidal bundles with the average twist degrees close to those predicted by the theoretical model. Constant-temperature simulations show that twisted toroidal bundles can be formed through successive processes of nucleation, growth, quick tightening, and slow tightening of the toroid, with the two last processes facilitating the polymer threading through the toroid’s hole. A relatively long chain of 512 beads has an increased dynamical difficulty to access the twisted bundle states due to the polymer’s topological constraint. Interestingly, we also observed significantly twisted toroidal bundles with a sharp U-shaped region in the polymer conformation. It is suggested that this U-shaped region makes the formation of twisted bundles easier by effectively reducing the polymer length. This effect can be equivalent to having multiple chains in the toroid.
Soliton locking phenomenon in bulk single crystal of monoaxial chiral magnet MnNb3S6
Authors: Ohkuma M. , Mito M. , Kousaka Y. , Ohe J. , Akimitsu J. , Kishine J. , Inoue K.
Published: February 2023

MnNb3S6 is a monoaxial chiral magnet and stabilizes magnetic solitons in the presence of a magnetic field (H). The number of solitons can be controlled by varying H. Furthermore, MnNb3S6 exhibits magnetization relaxation due to soliton annihilation, that is, a nonequilibrium chiral soliton lattice (CSL) state. In this study, we observed soliton locking phenomena in a CSL state on bulk MnNb3S6 crystal, as on micro-processed crystals of CrNb3S6. Thus, we could create nonequilibrium and equilibrium CSL states and switch between them. A numerical simulation revealed that the soliton number was preserved in the soliton locking region; thus, magnetization relaxation was not observed.
Energy natural orbital characterization of nonadiabatic electron wavepackets in the densely quasi-degenerate electronic state manifold
Authors: Arasaki Yasuki , Takatsuka Kazuo
Published: February 2023

Dynamics and energetic structure of largely fluctuating nonadiabatic electron wavepackets are studied in terms of Energy Natural Orbitals (ENOs) [K. Takatsuka and Y. Arasaki, J. Chem. Phys. 154, 094103 (2021)]. Such huge fluctuating states are sampled from the highly excited states of clusters of 12 boron atoms (B12), which have densely quasi-degenerate electronic excited-state manifold, each adiabatic state of which gets promptly mixed with other states through the frequent and enduring nonadiabatic interactions within the manifold. Yet, the wavepacket states are expected to be of very long lifetimes. This excited-state electronic wavepacket dynamics is extremely interesting but very hard to analyze since they are usually represented in large time-dependent configuration interaction wavefunctions and/or in some other complicated forms. We have found that ENO gives an invariant energy orbital picture to characterize not only the static highly correlated electronic wavefunctions but also those time-dependent electronic wavefunctions. Hence, we first demonstrate how the ENO representation works for some general cases, choosing proton transfer in water dimer and electron-deficient multicenter chemical bonding in diborane in the ground state. We then penetrate with ENO deep into the analysis of the essential nature of nonadiabatic electron wavepacket dynamics in the excited states and show the mechanism of the coexistence of huge electronic fluctuation and rather strong chemical bonds under very random electron flows within the molecule. To quantify the intra-molecular energy flow associated with the huge electronic-state fluctuation, we define and numerically demonstrate what we call the electronic energy flux.
Self-organizing single-line particle trains with differently shaped particles in a channel flow
Authors: Hu Xiao , Li Xinyu , Lin Peifeng , Zhu Zuchao
Published: February 2023

The inertial migration of differently shaped rectangular particles and elliptical particles in a channel flow and the self-organization of single-line particle trains are studied using the lattice Boltzmann method. The effects of particle shape, particle aspect ratio (α), Reynolds number (Re), blockage ratio (k), and particle concentration (Φ) on self-organizing single-line particle trains are explored. The results show that a single-line particle train is dynamically formed, with circular particle trains having a more pronounced dynamic process than rectangular and elliptical particle train. The inclination of height (IH) for the particles in the train is the main reason for the dynamic formation of a single-line particle train. Due to the changes of orientation angle under different flow conditions, the rectangular particle trains always have a larger IH and smaller interparticle spacing than the elliptical particle trains when the train is just formed. The effect of α on the spacing of elliptical particle trains is more sensitive than other shapes. Rectangular particles and elliptical particles with large Φ and Re and small k are prone to self-organize the single-line particle trains with stable spacing for a long travel distance. With increasing Φ, Re, and k, IH increases and the interparticle spacing decreases.
Dynamics of growth and detachment of single hydrogen bubble on horizontal and vertical microelectrode surfaces considering liquid microlayer structure in water electrolysis
Authors: Zhan Shuiqing , Yuan Rui , Wang Xiaohan , Zhang Wei , Yu Kai , Li Bin , Wang Zhentao , Wang Junfeng
Published: February 2023

The dynamics of the growth and detachment of a single hydrogen bubble on both the horizontal and vertical microelectrode surfaces in water electrolysis were synthetically investigated by combining the numerical simulation, force balance analysis, and available experimental data. Approximately, multiple steady simulation cases with different bubble diameters for different growth instances were conducted to state the actual unsteady bubble growth and detachment behavior. The numerical simulations of the temperature distribution considering the heat transfer caused by the liquid microlayer and induced Marangoni convection effects were performed. Then, a force balance model for predicting the bubble detachment diameter was developed by fully utilizing the simulated multi-physical field parameters and the experimental results of some key bubble geometric parameters. The presented numerical model and the force balance model were validated by comparing them with previous experimental data on the potential and the bubble detachment diameter, respectively. The simulation results indicate a significantly larger potential value occurs within the microlayer, and hence, the Joule heat of the electrolyte is mainly generated in the microlayer and then transferred to the bulk flow region. Obviously, the temperature gradient distribution is formed at the bubble interface, causing unstable Marangoni convection structure. The distribution patterns and evolutions of the electrolyte temperature, Marangoni convection velocity, and microlayer thickness for the horizontal and vertical microelectrode systems are significantly different. The present force balance model presents higher prediction accuracy for the bubble detachment diameters. Moreover, the in-depth force analysis results reveal that some dominant forces influence the bubble growth and detachment.
Changing interface conditions in a two-fluid rotating flow
Authors: Naumov Igor V. , Skripkin Sergey G. , Kvon Alexandr Z. , Shtern Vladimir N.
Published: February 2023

This experimental study reveals a striking nonlinear-physics phenomenon of fundamental and practical interest—changing conditions at the interface of two swirling immiscible fluids filling a vertical cylindrical container. To this end, we use a new measurement technique significantly advanced compared with prior studies. The rotating bottom disk drives a steady axisymmetric flow of both fluids. The lower fluid makes the centrifugal circulation (CC): It spirals on toroid surfaces going to the periphery near the bottom and going back to the axis near the interface. At a slow rotation (Re = 100), the upper fluid makes the anti-centrifugal circulation. As the rotation intensifies (Re = 175), the upper-fluid flow reverses into CC near the interface-axis intersection. For strong swirl (Re = 500), the CC occurs at the entire interface. In prior studies, the spatial resolution (1 mm) was insufficient to resolve the near-interface velocity field. Here, we use the advanced (light field) measurement technique, which has significantly better resolution (0.14 mm) and clearly shows that the radial velocity at the interface is negative for small Re and becomes zero for large Re. During these metamorphoses, the topology of the lower-fluid flow remains invariant, the interface has no visible deformation, and the flow is steady and axisymmetric.
High conductivity and low activation energy in p-type AlGaN
Authors: Rathkanthiwar Shashwat , Bagheri Pegah , Khachariya Dolar , Mita Seiji , Quiñones-García Cristyan , Guan Yan , Moody Baxter , Reddy Pramod , Kirste Ronny , Collazo Ramón , Sitar Zlatko
Published: February 2023

Record-low p-type resistivities of 9.7 and 37 Ω cm were achieved in Al0.7Ga0.3N and Al0.8Ga0.2N films, respectively, grown on single-crystal AlN substrate by metalorganic chemical vapor deposition. A two-band conduction model was introduced to explain the anomalous thermal behavior of resistivity and the Hall coefficient. Relatively heavy Mg doping (5 × 1019 cm−3), in conjunction with compensation control, enabled the formation of an impurity band exhibiting a shallow activation energy of ∼30 meV for a wide temperature range. Valence band conduction associated with a large Mg ionization energy was dominant above 500 K. The apparently anomalous results deviating from the classical semiconductor physics were attributed to fundamentally different Hall scattering factors for impurity and valence band conduction. This work demonstrates the utility of impurity band conduction to achieve technologically relevant p-type conductivity in Al-rich AlGaN.
Compact optomechanical accelerometers for use in gravitational wave detectors
Authors: Hines A. , Nelson A. , Zhang Y. , Valdes G. , Sanjuan J. , Guzman F.
Published: February 2023

We present measurements of an optomechanical accelerometer for monitoring low-frequency noise in gravitational wave detectors, such as ground motion. Our device measures accelerations by tracking the test-mass motion of a 4.7 Hz mechanical resonator using a heterodyne interferometer. This resonator is etched from monolithic fused silica, an under-explored design in low-frequency sensors, allowing a device with a noise floor competitive with existing technologies but with a lighter and more compact form. In addition, our heterodyne interferometer is a compact optical assembly that can be integrated directly into the mechanical resonator wafer to further reduce the overall size of our accelerometer. We anticipate this accelerometer to perform competitively with commercial seismometers, and benchtop measurements show a noise floor reaching 82 pico-g Hz−1/2 sensitivities at 0.4 Hz. Furthermore, we present the effects of air pressure, laser fluctuations, and temperature to determine the stability requirements needed to achieve thermally limited measurements.
Injectable hydrogels of enzyme-catalyzed cross-linked tyramine-modified gelatin for drug delivery
Authors: Tang Yuanhan , Ding Junjie , Zhou Xun , Ma Xintao , Zhao Yi , Mu Qiyu , Huang Zixu , Tao Qian , Liu Fangjie , Wang Ling
Published: February 2023

Enzymatically catalyzed cross-linking is a hydrogel fabrication method that generally is considered to have lower cytotoxicity than traditional chemical cross-linking methods. In order to optimize the properties of injectable hydrogels and expand their applications, an enzyme-catalyzed cross-linked injectable hydrogel was designed. The tyramine-modified gelatin (G-T) was formed into a stable injectable hydrogel by the combination of horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) catalysis. 1H NMR spectroscopy was used to demonstrate the successful modification of gelatin by tyramine. The surface morphology of the prepared hydrogels was characterized jointly by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Rheological tests demonstrated the tunable mechanical strength, formation kinetics, shear thinning and good self-recovery properties of the hydrogels. In addition, the hydrogels can be formed into various shapes by injection. The hydrogel network structure is complex and interlaced, as such it is suitable to encapsulate drugs for controlled release. The drug release from the prepared hydrogels followed the Peppas–Sahlin model and belonged to Fickian diffusion. This study constructed injectable hydrogels through the enzyme-catalyzed cross-linking of modified gelatin and applied the hydrogels for drug release, which is expected to expand the application in biomedical fields.
The effects of templates and seeds on the properties of nanosheet SAPO-34 molecular sieves and their catalytic performance in the MTO reaction
Authors: Jiang Tao , Bai Yingzhi , Li Lu , Tai Weiwei , Wang Yujia , Wang Haiyan , Sun Na
Published: February 2023

Nanoscale SAPO-34 molecular sieves were synthesized by adding different types of seed into hydrothermal synthesis systems with tetraethylammonium hydroxide (TEAOH) and triethylamine (TEA) & tetraethylammonium bromide (TEABr) as templates. The effects of different types of template and seed on the crystal structure, morphology, grain size and acidity of the molecular sieves were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), N2 isothermal adsorption–desorption and ammonia temperature-programmed desorption (NH3-TPD). The methanol-to-olefins (MTO) reaction performance of the synthesized samples was investigated in a fixed-bed reactor. The results showed that crystalline supernatant and seed soaking solution could be used as liquid seeds to assist in the synthesis of SAPO-34 molecular sieves with a lamellar structure. The yield of SAPO-34 synthesized by seed increased from 38.64 to 59.68%, and the methanol conversion rate was significantly improved as compared with that of SAPO-34 synthesized without seed. The nano-thickness of SAPO-34 synthesized with TEA&TEABr instead of TEAOH as template decreased from 100–150 to 40–50 nm, and the lifetime increased from 360 to 400 min with the original yield kept constant.
Simulating the population dynamics of barley grass (Hordeum spp.) and impacts of weed management strategies in a southern Australian lucerne (Medicago sativa) pasture
Authors: Kelly Jane E. , Behrendt Karl , Quinn Jane C.
Published: February 2023

Context Barley grass (Hordeum spp. L.) is an annual, invasive grass weed of southern Australian crops and pastures, frequently associated with weight loss and carcass damage in sheep due to its sharp seeds. Knowledge gaps exist regarding optimal density thresholds for effective control to reduce impacts on animal production. The value of integrated weed management (IWM) over individual control options for reducing barley grass populations in pasture is also unknown. Aims We aimed to develop a model for simulating the population dynamics of barley grass within lucerne (Medicago sativa L.) pastures of southern Australia and to test the hypothesis that combining herbicides with mowing will be more effective for removing barley grass seedbanks over time than individual control measures. Methods The model was developed within Microsoft Excel and adapted from other annual grass models. The model takes a Monte Carlo approach to simulate control impacts on weed seedbanks over 10 years using five weed-control density thresholds. It was parameterised using data from recent experiments and available literature. Key results The most effective long-term control strategy for barley grass occurred with a density threshold of 5 seedlings m−2 by combining early and late herbicide applications, and by combining early and late herbicides with mowing, reducing the seedbank by 86% and 89%, respectively. Conclusions Simulation results showed that IWM programs were more effective than individual control options in reducing the barley grass seedbanks over 10 years, particularly at low weed densities (≤50 seedlings m−2). Implications Incorporation of this model into a bioeconomic grazing systems model will be valuable for determining the economic impacts and optimal weed-control strategies for minimising the effects of barley grass seed contamination in lamb production systems.
Diverse systems and strategies to cost-effectively manage herbicide-resistant annual ryegrass (Lolium rigidum) in no-till wheat (Triticum aestivum)-based cropping sequences in south-eastern Australia
Authors: Swan Antony D. , Goward Laura , Hunt James R. , Kirkegaard John A. , Peoples Mark B.
Published: February 2023

Context Herbicide-resistant annual ryegrass (Lolium rigidum; ARG) is a major weed of commercial significance globally, including no-till wheat-based production systems in south-eastern Australia. Aims To compare the cost-effectiveness of different crop sequences and intensities of weed management to control ARG in rainfed grain production. Methods Two on-farm studies in southern New South Wales, Australia, compared the effect of combinations of 3-year crop-sequence options (continuous wheat, 1- or 2-years of break crops), conservative or aggressive weed-control measures, hay cuts, legume brown manure (BM), and/or weed-free winter fallow on in-crop ARG infestations and soil seedbanks. Gross margins were calculated for each combination of treatments to compare system economic performance. Key results Double-breaks consisting of two consecutive broadleaf crops, or canola–cereal hay, were frequently the most profitable and effective ARG control strategies. Single canola or lupin crops, BM, cereal hay, and fallow all significantly reduced subsequent in-crop ARG and seedbank numbers compared with continuous wheat. Aggressive in-crop control measures in wheat were more expensive than those applied to break crops. Gains in ARG control could be lost by a single year of poor weed control. Conclusions High levels of control (>95%) over three consecutive seasons are required to reduce ARG seedbanks, and this is most cost-effectively achieved with diverse crop sequences. Implications Farmers with high populations of ARG can reduce seedbanks by growing three crops sequentially that achieve complete weed seed control. This must be followed with ongoing high levels of control in subsequent years to keep ARG seedbanks low.
Fine-scale variability in catch and growth rates of western rock lobsters (
Authors: Miller A. , de Lestang S. , How J. , Gibbons B. , Lester E. , Navarro M. , Fitzhardinge J. , Brooker M. , Langlois T.
Published: February 2023

Context The western rock lobster fishery is recognised to be conservatively managed, with breeding stock levels estimated to be at record levels over the past decade. Despite this, anecdotal reports from commercial fishers identified an area of unexpectedly low catches in the centre of the fishery and lobsters’ biogeographic distribution. Aim To confirm the presence of this suspected ‘low-catch’ zone and examine the variability in catch and growth rates of lobsters if identified. Methods This study conducted an intensive mark–recapture survey over 8 months to explore catch rate, density, movement and growth rates across this ‘low-catch’ zone and three comparable locations. Key results In total, 9318 lobsters were caught and 7565 individuals were tagged during the study. Consistently low catch rates of under-sized lobsters were observed in the ‘low-catch’ zone, with catch rates increasing with distance from the zone. By contrast, similar catch rates of legal-sized lobsters were observed across all locations. Conclusions The study confirmed low catch rates, for under-sized lobsters, within an area of perceived low catch rates within the centre of the fishery. The lack of difference found in legal-sized catch rates among locations is likely to be due to the low fishing pressure in the ‘low-catch’ zone, resulting from hyperstability of fishers adapting to the historical perceived low catch rate. Modelled data demonstrated the ‘low-catch’ zone to be associated with faster growth rates and high fine-scale migration, indicating a potential release from density-dependent processes. Implications We anticipate that these results will be a useful starting point for future research into the mechanisms responsible for the unexpectedly low catch of sublegal lobsters within the ‘low-catch’ zone and the implications it may have on the wider population, both regionally and across the species distribution.