bluuebunny/crossref_metadata_2025 huggingface dataset:
Polarized signatures of orbiting hot spots: Special relativity impact and probe of spacetime curvature
Authors: Vincent F. H. , Wielgus M. , Aimar N. , Paumard T. , Perrin G.
Published: February 2024

Context. The Galactic Center supermassive black hole is well known to exhibit transient peaks of flux density on a daily basis across the spectrum. Recent infrared and millimeter observations have strengthened the case for the association between these flares and circular orbital motion in the vicinity of the event horizon. The strongly polarized synchrotron radiation associated with these events leads to specific observables called QU loops, that is, looping motion in the Stokes QU plane of linear polarization. These patterns have been observed by the Submillimeter Array, VLTI/GRAVITY, and ALMA.

Aims. We want to deepen the understanding of the QU loops associated with orbiting hot spots. To this end, we computed such loops in Minkowski and Schwarzschild spacetimes in order to determine which aspects of the observed patterns are due to special- or general-relativistic phenomena.

Methods. We considered a parcel of energized plasma in circular motion in Minkowski spacetime and in Keplerian orbit in the Schwarzschild spacetime. We computed, using the GYOTO ray-tracing code, the polarized radiative transfer associated with this orbiting hot spot and derived the evolution of the flux density, astrometry, and Stokes Q and U parameters.

Results. We show that QU loops in Minkowski spacetime at low or moderate inclination i ≲ 45° (where i = 0° is a face-on view) share all the qualitative features of Schwarzschild QU loops. There exist QU loops for all setups considered (including for the face-on view and vertical magnetic field), there may be one or two QU loops per orbital period for a vertical magnetic field configuration, and there are always two QU loops in case of a toroidal magnetic field. The simplicity of Minkowski spacetime is a key asset for allowing us to provide analytical formulas that explain the details of this behavior. Moreover, we analyzed the flux variation of the hot spot and show that it is dictated either by the angular dependence of the radiative transfer coefficients or by relativistic beaming. In the former case, this can lead to extreme flux ratios, even at a moderate inclination. Finally, we highlight the increasing mirror asymmetry of the Schwarzschild QU track with increasing inclination and show that this behavior is a specific Schwarzschild feature caused by light bending.

Conclusions. Although special-relativistic effects have not been extensively discussed in this context, they are a crucial part in generating the observed QU loops. However, general-relativistic light bending leads to a specific observable feature encoded in the asymmetry of the observed loops, and this feature might allow the spacetime curvature to be quantified.
The phase-space distribution of the M 81 satellite system
Authors: Müller Oliver , Heesters Nick , Pawlowski Marcel S. , Jamie Kanehisa Kosuke , Lelli Federico , Libeskind Noam I.
Published: February 2024

The spatial distribution of dwarf galaxies around their host galaxies is a critical test for the standard model of cosmology because it probes the dynamics of dark matter halos and is independent of the internal baryonic processes of galaxies. Comoving planes of satellites have been found around the Milky Way, the Andromeda galaxy, and the nearby Cen A galaxy, which seems to be at odds with the standard model of galaxy formation. Another nearby galaxy group, with a putative flattened distribution of dwarf galaxies, is the M 81 group. In this paper, we present a quantitative analysis of the distribution of the M 81 satellites using a Hough transform to detect linear structures. Using this method, we confirm a flattened distribution of the dwarf galaxies. Depending on the morphological type, we find a minor-to-major axis ratio of the satellite distribution of 0.5 (all types) or 0.3 (dSph), which is in line with previous results for the M 81 group. Comparing the orientation of this flattened structure in 3D with the surrounding large-scale matter distribution, we find a strong alignment with the local sheet and the planes of satellites around the Andromeda galaxy and Cen A. Furthermore, the satellite system seems to be lopsided. Employing line-of-sight velocities for a subsample of the dwarfs, we find no signal of corotation. Comparing the flattening and motion of the M 81 dwarf galaxy system with TNG50 of the IllustrisTNG suite we find good agreement between observations and simulations, but caution that i) velocity information of half of the satellite population is still missing, ii) current velocities mainly come from dwarf irregulars clustered around NGC 3077, which may indicate an infall of a dwarf galaxy group, and iii) some of the dwarfs in our sample may be tidal dwarf galaxies. From the missing velocities, we predict that the observed frequency within IllustrisTNG may still range between 2 to 29%. Any final conclusions about the agreement or disagreement with cosmological models needs to wait for a more complete picture of the dwarf galaxy system.
Pädiatrische Themen im Fokus
Authors: Kathmann Wiebke
Published: February 2024

Beim Kongress des American College of Rheumatology (ACR) in San Diego im November 2023 nahmen pädiatrische Themen so breiten Raum ein wie nie zuvor: 19 Sitzungen und mehrere Abstract-Sessions zu wissenschaftlichen und klinischen Fragen bei rheumatischen Erkrankungen im Kindes- und Jugendalter standen auf dem Programm. Hier ein paar Highlights.
Hämatologie in der pädiatrischen Praxis
Authors: Génevaux Franziska , Barucija Ajla , Hierdeis Kilian , Hock Louisa , Eber Stefan
Published: February 2024

Anämien sind heterogen und vielfältig, daher werden besonders seltene Anämieformen häufig unterdiagnostiziert. Eine ausführliche Diagnostik im klinischen Alltag ist deshalb notwendig. Zum Ausschluss häufiger Anämieursachen sollten immer eine eingehende klinische Anamnese und Diagnostik mit der Suche nach Infektionen oder Tumoren, Hämolysezeichen und Coombs-Test erfolgen. Als Differenzialdiagnose bei verändertem Blutbild muss auch an ein malignes Geschehen gedacht werden. Nur durch das Ausschließen zahlreicher Differenzialdiagnosen lassen sich seltene Anämien detektieren und adäquat behandeln.

Die Eisenmangelanämie ist die häufigste Anämieform, die sich mit einer mikrozytären, hypochromen Anämie im Blutbild präsentiert. Ursache ist entweder eine zu geringe Zufuhr, eine schwache Absorption (zum Beispiel bei Zöliakie) oder eine vermehrte Ausscheidung von Eisen. Therapeutisch kann eine orale Therapie mit Fe2+ (Ferrosanol-Tropfen/Kapseln) eingeleitet werden und bei schwerer, therapieresistenter Eisenmangelanämie sollte eine Eisentransfusion in Erwägung gezogen werden.

Bei der Sichelzellerkrankung kommt es zu mehr oder weniger schweren Gefäßverschlüssen, chronischer Hämolyse und Infektbereitschaft durch funktionelle Asplenie. Eine Prophylaxe mit Hydroxycarbamid kann Sichelzellkrisen vorbeugen, die einzig kausale Therapie ist die allogene Stammzellentransplantation.

Die hereditäre Sphärozytose und der Pyruvatkinase-Mangel sind in Mitteleuropa die häufigsten, genetisch bedingten chronischen hämolytischen Anämien. Bei diesen beiden Erkrankungen ist durch einfache hämatologische Untersuchungen eine Unterteilung in verschiedene Schweregrade der Erkrankung möglich. Diese Einteilung erlaubt eine prognostische Aussage über den zu erwartenden klinischen Verlauf und die Einleitung einer adäquaten Therapie. Als erste kongenitale hämolytische Anämie kann der Pyruvatkinase-Mangel molekular durch Mitapivat behandelt werden. Dieser Therapieversuch sollte vor der Splenektomie erfolgen. Bei der Sphärozytose sollte eine nahezu totale Splenektomie (NTS) der vollständigen Splenektomie vorgezogen werden, da dadurch die immunologische Milzfunktion erhalte werden kann.

Weitere wichtige Anämien sind die Autoimmunhämolytischen Anämien (AIHA). Sie werden durch eine Bildung von Antikörpern gegen Antigene auf autologen Erythrozyten charakterisiert. Die zwei häufigsten Vertreter sind die durch Wärme- und Kälteantikörper ausgelösten AIHA. Therapeutisch können Steroide und bei Steroidresistenz Immunsuppressiva angewandt werden.

Renale Anämien sind sehr selten und treten bei Kindern mit chronischem Nierenversagen, meist als Folge kongenitaler Nephropathien, auf. Es sollten einerseits die Verbesserung der Nierenfunktion, andererseits die Stimulation der Erythropoese als therapeutische Ansätze erwogen werden.
Breastfeeding Rates During the COVID-19 Pandemic in Germany: Data
from the CRONOS Registry
Authors: Longardt Ann Carolin , Zöllkau Janine , Mand Nadine , Wowretzko Feline , Büchel Johanna , Andresen Kristin , Hoyer Bimba Franziska , Kraft Katrina , Pecks Ulrich ,   Collaborating authors
Published: February 2024

SARS-CoV-2 infection and COVID-19 disease are thought to have an impact on
breastfeeding rate – besides other known peripartal issues. Data of the
national CRONOS registry regarding breastfeeding behavior in 6,746 women was
analyzed regarding the time window between maternal SARS-CoV-2 infection and
time of delivery. In addition, other influencing factors like the predominant
viral variant, maternal disease severity, and gestational age at delivery were
taken into account. Our data suggest that within the variables analyzed, in the
case of acute maternal infection (<14 days before birth), breastfeeding
behavior improved with increasing gestational age at birth (p<0.0001),
with less severe maternal illness (p<0.0001) and as the pandemic
progressed with less virulent viral variants (p=0.01). When adjusting
for COVID-19-associated and non-associated factors, rooming-in remains the most
important factor positively influencing breastfeeding behavior. With regards to
the benefits for mother and infants from breastfeeding, a separation of mother
and child even in case of infectious settings should be avoided.
Nausea and Vomiting of Pregnancy and its Management with the Dual-Release Formulation of Doxylamine and Pyridoxine
Authors: Schleußner Ekkehard , Jäkel Susan , Keck Christoph , Kuhlmann Kirsten , Mangler Mandy , Paulus Wolfgang E. , Eiblwieser Johanna , Steeb Theresa , Regidor Pedro-Antonio
Published: February 2024

Nausea and vomiting of pregnancy (NVP) is among the most common conditions that pregnant women encounter in the early stages of pregnancy. It can affect up to 85% of pregnant women, thus representing a significant public health concern. NVP results in substantial negative physical, emotional, and financial consequences. Despite its prevalence, the pathogenesis remains elusive. Few guidelines have been published; however, several interventions exist for the symptomatic treatment of NVP.

The aim of this review is to provide an overview of modern treatment strategies of NVP with a special focus on the recently approved dual-release formulation of the doxylamine and pyridoxine combination. This combination was approved by the Food and Drug Administration (FDA) in November 2016 for the treatment of NVP when conservative management fails, and it has been introduced to the American market in April 2018.

The maximum plasma concentration (Tmax) of doxylamine and pyridoxal-5-phosphate
is reached 3.5 h and 15 h, respectively, after administration of one tablet twice daily,
or 4.5 h and 0.5 h, respectively, when one tablet is administered just once
daily.

In addition, the delayed-release combination allows sufficient levels of doxylamine and the
active metabolite pyridoxal-5-phosphate in the systemic circulation, providing symptoms
relief in the subsequent morning.

Hence, the dual-release formulation can improve the quality of life of pregnant women
suffering from NVP. Additionally, large epidemiological trials have shown no increased
risk of adverse effects to newborns, demonstrating that its use is not
teratogenic.
Zum Themenschwerpunkt „Erfahrungen aus der Pandemie –
ein datenbasierter Rückblick“
Authors: Pecks Ulrich
Published: February 2024

Die Menschheit in einer globalisierten Welt war in der Vergangenheit mit
verschiedenen Herausforderungen konfrontiert, die gravierende Auswirkungen auf das
tägliche Leben, die Wirtschaft und die Gesundheitssysteme hatten. Genannt
seien die Spanische Grippe 1918–1919, die Ölkrise der 1970er-Jahre
mit der Folge einschneidender Maßnahmen wie Energieeinsparungen und
Rationierung, die AIDS-Pandemie oder die Finanzkrise und Wirtschaftsrezession von
2008.
Neues zum Behçet-Syndrom
Authors: Xenitidis Theodoros , Henes Jörg Christoph
Published: February 2024

Was ist neu?

Immunpathogenese und Genetik Auch beim BS (Behçet-Syndrom) spielt die Neutrophilen-
(Hyper-)Aktivierung und die daraus hervorgehende NETosis eine wichtige Rolle.

Klinische Befunde Neben den 4 Kardinalsymptomen – nämlich rezidivierende orale Aphthen, genitale Aphthen sowie Haut- und Augenläsionen – bietet das Krankheitsbild zahlreiche weitere Manifestationen, die häufig eine interdisziplinäre Zusammenarbeit erfordern. Dies gilt neben der Augenbeteiligung, die bei inadäquater Behandlung immer noch zur Erblindung führen kann, insbesondere auch für intestinale und zerebrale Manifestationen sowie für die Großgefäß-Vaskulitis.

Therapie Eine letzte Überarbeitung der EULAR-Empfehlungen erfolgte 2018. Die Empfehlungen sind mittlerweile als wichtiger Behandlungsleitfaden international etabliert. Die Therapie richtet sich nach der führenden Organbeteiligung. Nachdem 2016 Adalimumab eine Zulassung für die Behandlung der hinteren Augenbeteiligung erhielt, steht mit Apremilast seit 2020 ein weiterer Wirkstoff zur Verfügung. Empfohlen wird das Medikament für die Behandlung rezidivierender oraler Aphthen bei erwachsenen Behçet-Patienten, die einer systemischen Therapie bedürfen. Es besteht dennoch ein weiterer Bedarf an neuen Substanzen.
Synthesis of Amides and Peptides by Employing [4-(Acetylamino) phenyl]imidodisulfuryl Difluoride (AISF) as a Coupling Reagent
Authors: Bharamawadeyar Swetha , Chetankumar Eti , Srinivasulu Chinthaginjala , Sureshbabu Vommina V.
Published: February 2024

A new synthetic approach for the preparation of amides and peptides containing amino acids as well as aryl acids and amines by employing [4-(acetylamino)phenyl]imidodisulfuryl difluoride (AISF) as a carboxylic acid activator under mild conditions is delineated. The use of AISF as an acid activator allows the reaction to be performed efficiently. This operationally simple amidation is amenable to a wide variety of carboxylic acids and Nα-protected amino acids. Further, racemization did not occur during the coupling. In addition, a gram-scale reaction is demonstrated.
Gustav Peter Bucky: An Engineer in the Service of Health
Authors: Sudoł-Szopińska Iwona , Panas-Goworska Marta , Glaser Christian
Published: February 2024

This history page in the series “Leaders in MSK radiology” is dedicated to the memory and achievements of the German radiologist Gustav Peter Bucky who invented the Bucky diaphragm grids. He wanted to become an engineer but bowed to his parents' wishes and went to medical school. By using his technical skills, he made revolutionary contributions to the early X-ray technique.
Integrating the humanities and the social sciences: six approaches and case studies
Authors: Case Brendan , VanderWeele Tyler J.
Published: February 2024

The social sciences are still young, and their interaction with older siblings such as philosophy and theology is still necessarily tentative. This paper outlines three ways in which humanistic disciplines such as philosophy and theology might inform the social sciences and three in which the social sciences might inform the humanities in turn, proceeding in each case by way of brief “case studies” to exemplify the relation. This typology is illustrative rather than exhaustive, but each of its halves nonetheless roughly tracks the development of a research project in the social sciences and humanities, respectively. In the first direction, (1) the humanities can help the social sciences identify new directions and scope for their inquiry; (2) provide conceptual clarity for constructs that the social sciences elect to study; and (3) enrich & clarify the interpretation of empirical results. Moving in the opposite direction, the social sciences can help (4) furnish new data for humanistic reflection; (5) confirm (or challenge) claims from the humanities; and (6) develop and assess interventions for achieving the goods highlighted by humanistic inquiry.
Exploring the impact of beauty vloggers’ credible attributes, parasocial interaction, and trust on consumer purchase intention in influencer marketing
Authors: Garg Mukta , Bakshi Apurva
Published: February 2024

The growing usage of digital platforms has made influencer marketing the most cost-effective marketing tool, especially for products consumed by young digital natives. Among other products, these include fashion and beauty-related items such as cosmetics, whose online marketing has created a particular category of influencers called ‘beauty vloggers.’ By applying the source credibility model, this study investigates whether beauty vloggers’ credible attributes (trustworthiness, expertise, and attractiveness) help consumers build trust towards them and whether followers’ trust leads to desirable marketing outcomes (increased purchase intention). Prior literature used the source credibility model in a fragmented manner. However, this study enhances the holistic framework of social media influencers’ impact on purchase intention by investigating all three credible attributes. It specifically addresses the significance of cultivating trust between beauty vloggers and followers, exploring the impact of vloggers’ credible attributes on consumer purchase intention. Additionally, beauty vloggers periodically engage in parasocial interactions to increase closeness with their audiences, affecting consumer behaviour. This study addresses the limited research on the consequences of parasocial interactions in an emerging market context, examining the impact of beauty vloggers’ repeated interactions on consumer behaviour, contributing to a comprehensive understanding of purchase intention using parasocial interaction as an antecedent. The research was conducted on consumers belonging to the age group of 16–45 who use social media platforms daily. Using structural equation modelling via SmartPLS software, the statistical analysis was done on 357 North Indian respondents. The study explores the influence of beauty vloggers on consumers’ purchasing behaviour in the Indian context. The results demonstrate that beauty vloggers’ credibility traits help in influencing consumer behaviour. The findings also revealed that trust partially mediates the impact of credible attributes of beauty vloggers and consumers’ purchase intention. Additionally, the results show that customers’ purchasing decisions might be influenced by repeated parasocial interactions done by beauty vloggers if they perceive them as credible information sources. The findings of the study contribute to help industrial marketers and practitioners of cosmetic companies use influencer marketing strategically in order to increase market sales.
Lysosome-related organelles contain an expansion compartment that mediates delivery of zinc transporters to promote homeostasis
Authors: Mendoza Adelita D. , Dietrich Nicholas , Tan Chieh-Hsiang , Herrera Daniel , Kasiah Jennysue , Payne Zachary , Cubillas Ciro , Schneider Daniel L. , Kornfeld Kerry
Published: February 2024

Zinc is an essential nutrient—it is stored during periods of excess to promote detoxification and released during periods of deficiency to sustain function. Lysosome-related organelles (LROs) are an evolutionarily conserved site of zinc storage, but mechanisms that control the directional zinc flow necessary for homeostasis are not well understood. In
Caenorhabditis elegans
intestinal cells, the CDF-2 transporter stores zinc in LROs during excess. Here, we identify ZIPT-2.3 as the transporter that releases zinc during deficiency; ZIPT-2.3 transports zinc, localizes to the membrane of LROs in intestinal cells, and is necessary for zinc release from LROs and survival during zinc deficiency. In zinc excess and deficiency, the expression levels of CDF-2 and ZIPT-2.3 are reciprocally regulated at the level of mRNA and protein, establishing a fundamental mechanism for directional flow to promote homeostasis. To elucidate how the ratio of CDF-2 and ZIPT-2.3 is altered, we used super-resolution microscopy to demonstrate that LROs are composed of a spherical acidified compartment and a hemispherical expansion compartment. The expansion compartment increases in volume during zinc excess and deficiency. These results identify the expansion compartment as an unexpected structural feature of LROs that facilitates rapid transitions in the composition of zinc transporters to mediate homeostasis, likely minimizing the disturbance to the acidified compartment.
L1 novice writing as a missing piece in the Learner Corpus Research puzzle
Authors: Jadoulle Pauline
Published: February 2024

This paper investigates the possible benefits of integrating an L1 novice corpus into the study of learner
writing, through a study on hedging adverbials and complement clauses. A more traditional tripartite comparison is first drawn
between French EFL learner writing, L1 English novice writing, and English expert writing. Then, a comparison is made between L1
French novice writing and French EFL learner writing. The study uses data from the following corpora: the Varieties of
English for Specific Purposes dAtabase (VESPA; Paquot et al., 2022)
(French EFL learner writing), the British Academic Written English (BAWE; Heuboeck et al., 2008) corpus and the Michigan Corpus of Upper-level Student Papers (MICUSP; Ädel & Römer, 2012) (both L1 English novice writing), the Kulturell Identitet
i Akademisk Prosa: nasjonal versus disiplinavhengig (KIAP‑EN; Fløttum et al.,
2006) corpus (English expert writing), and the The French Academic wRiting (FAR) corpus (L1 French
novice writing). The results speak to the importance of including a L1 novice component to the current methodologies employed in
Learner Corpus Research (LCR), since such inclusion helps to provide a better and more nuanced interpretation of the findings
obtained by means of a more traditional tripartite approach.
J’avoueetc’est le cas de le dire
Authors: Vassiliadou Hélène
Published: February 2024

Cet article décrit le fonctionnement de deux opérateurs discursifs, l’un formé surdire(c’est le cas de le dire) et l’autre sur le verbe performatifavouer(j’avoue). Nous en fournissons une description syntactico-sémantique et nous examinons les éventuelles raisons de blocage de l’apparition de l’un à la place de l’autre selon les contraintes suivantes : affaiblissement de l’acte de l’aveu, exigence d’une polarité négative, d’un haut degré et/ou d’une situation exemplaire. Ces éléments pris en compte, nous faisons ressortir les spécificités des deux opérateurs soumis à l’étude.
A migrant’s public apology as an instance of internalized racism
Authors: Archakis Argiris , Tsakona Villy
Published: February 2024

The aim of this chapter is to investigate how racio-national discourse influences the way migrants perceive
themselves and frame their trajectories in the host community. Within a CDA framework, we analyze an article written by a
young migrant and published in a Greek newspaper of leftwing and antiracist orientation. The article appears to belong to the
genre of public apologies, since the author projects migrants as offenders who harmed the victimized majority. We argue that
such representation of reality indicates migrants’ internalized racism and simultaneously renders the article an instance of
liquid racism, as it is published in a newspaper of antiracist orientation. Through migrants’ reproduction of majority’s
racist accusations against them, the hegemony of Greek racio-national discourse is reinforced.
Enhanced terahertz frequency mixing in all-dielectric metamaterial with multiple surface plasmon polaritons resonances
Authors: Wang Baoku , Yan Fei , Tian Fengjun , Sun Weimin , Li Li
Published: February 2024

Nonlinear metamaterials hold a promising platform for generating terahertz (THz) waves. In this paper, we present an all-dielectric metamaterial with multiple surface plasmon polariton (SPP) resonances for enhanced THz frequency mixing. The metamaterial is composed of graphene ribbons, a dielectric layer, and a one-dimensional photonic crystal, displaying the multiple absorptions with simultaneous excitation of three SPP resonances. Taking advantage of SPP resonances with high Q factor and strong localized field at the input frequency, the third-order nonlinear processes are remarkably enhanced, including third-harmonic generation and four-wave mixing, producing a variety of frequencies in the THz range. The proposed efficient nonlinear metamaterials offer promising applications for THz frequency synthesis.
Revealing magnetic and physical properties of TbFe4.4Al7.6: experiment and theory
Authors: Samatham S Shanmukharao , Singh Saurabh , Shravan Kumar Reddy S , A Santhosh Kumar , Yadam Sankararao , Babu P D , Takeuchi Tsunehiro , Suresh K G
Published: February 2024

We report on the magnetic, electrical transport, caloric and electronic structure properties of TbFe4.4Al7.6 polycrystalline alloy using experiment and theory. The alloy crystallizes in tetragonal structure with I4/mmm space group with lattice parameters a = b = 8.7234(5) Å and c = 5.0387(6) Å. It is ferrimagnetic with a compensation temperature of

T

c
m
p

∼

151 K, Curie–Weiss temperature

θ

C
W

∼

172.11 K and an effective magnetic moment

μ

e
f
f

= (2.37±0.07)

μ

B

/f.u with Z = 2. At low temperatures, kinetic arrest-like first-order phase transition is realized through the thermal hysteresis between field-cooled cooling and field-cooled warming curves of M(T) and virgin curves of M(H) and

ρ
(
H
)

which are outside the hysteresis loops with metamagnetic transition. The high magnetic field suppression of multiple transitions and reduced coercive field

H

c
o
e
r

and remnant magnetization

M

r
e
m

with increasing temperature are reported.

H

c
o
e
r

and

M

r
e
m

cease to exist above the compensation temperature

T

c
m
p

. A correlation between the isothermal magnetization and resistivity is discussed. Specific heat C(T) analysis reveals a Sommerfeld parameter of γ = 0.098 

J

⋅

m
o
l

−
1

⋅

K

−
2

and a Debye temperature of

θ

D

∼
351.2

 K. The sample is metallic as inferred from the

ρ
(
T
)

behavior and Sommerfeld parameter. The magnetoresistance of the alloy is low and negative which indicates the suppression of weak spin-fluctuations. This alloy avoids the tricritical point despite first-to-second order phase transition. The electronic and magnetic structure calculations, by making use of full potential linearized augmented plane wave method, suggest metallic ferrimagnetic ground state of TbFe4.4Al7.6 with Tb atoms contributing ferromagnetically (5.87

μ

B

) and Fe atoms with antiferromagnetic contribution (2.67

μ

B

), in close agreement with the experimental observation.
High harmonic generation in graphene quantum dots
Authors: Zafar Ahmal Jawad , Mitra Aranyo , Apalkov Vadym
Published: February 2024

We study theoretically the generation of high harmonics in disk graphene quantum dots placed in linearly polarized short pulse. The quantum dots (QD) are described within an effective model of the Dirac type and the length gauge was used to describe the interaction of quantum dots with an optical pulse. The generated radiation spectra of graphene quantum dots can be controlled by varying the quantum dot size, i.e. its radius. With increasing the quantum dot radius, the intensities of low harmonics mainly decrease, while the cutoff frequency increases. The sensitivity of the cutoff frequency to the QD size increases with the intensity of the pulse.
Statistics of grain microstructure evolution under anisotropic grain boundary energies and mobilities using threshold-dynamics
Authors: Kim Jaekwang , Admal Nikhil Chandra
Published: February 2024

This paper investigates the statistics of two-dimensional grain microstructures during grain growth under anisotropic grain boundary (GB) energies and mobilities. We employ the threshold dynamics method, which allows for unparalleled computational speed, to simulate the full-field curvature motion of grain boundaries in a large polycrystal ensemble. Two sets of numerical experiments are performed to explore the effect of GB anisotropy on the evolution of microstructure features. In the first experiment, we focus on abnormal grain growth and find that GB anisotropy introduces a statistical preference for certain grain orientations. This leads to changes in the overall grain size distribution from the isotropic case. In the second experiment, we examine the development of texture and the growth of twin boundaries for different initial microstructures. We find that texture development and twin growth are more pronounced when the initial microstructure has a dominant fraction of high-angle grain boundaries. Our results suggest effective GB engineering strategies for improving material properties.
Atomistically informed dislocation dynamics simulations: application to dislocation-loop interactions in zirconium
Authors: Dupuy L M , Kassem W , Clouet E , Onimus F
Published: February 2024

Neutron irradiation of zirconium alloys leads to the formation of high densities of small dislocation loops. Their interactions with gliding dislocations are responsible for hardening and early necking of the material. Multi-scale numerical simulations of the interactions between dislocations and loops are undertaken to predict the mechanical properties evolution of these materials due to irradiation. Molecular dynamics simulations are first performed to assess the critical ingredients needed for dislocation dynamics simulations. Appropriate models and associated coefficients are then introduced in dislocation dynamics simulations in order to reliably reproduce the dislocation line energy, the cross-slip process from basal to prismatic planes and the mobility of straight and jogged dislocations. Based on this parametrization, interactions between dislocations and loops are finally computed with the two numerical methods. Careful comparisons between the two types of simulations show qualitative and quantitative agreement, opening the path to investigations of irradiation effects at the grain scale through large scale dislocation dynamics simulations.
Metal nanoparticles to improve the heat resilience in wheat (Triticum aestivum L.)
Authors: Shukla Gyanika , Singh Amardeep , Chaudhary Neha , Singh Swati , Basnal Namita , Gaurav Shailendra Singh
Published: February 2024

This study evaluated the efficacy of phytogenic silver and zinc nanoparticles in improving heat resilience in various wheat varieties. The silver and zinc nanoparticles were synthesized using plant leaf extract and characterized using various techniques. Four wheat varieties (DBW187, Black Wheat, DBW 50, and PBW 621) were subjected to field trials. The random block design was used, and nanoparticles in different concentrations were applied at various growth stages and morphologically, and yield parameters were recorded. UV–vis spectroscopy spectral analysis showed peaks for Ag nanoparticles at 420 nm wavelength and Zn nanoparticles at 240 and 350 nm wavelength, depicting the preliminary confirmation of nanoparticle synthesis. Electron microscopic analysis (TEM and SEM) provided morphological insights and confirmed synthesis of fine-sized particle mostly in a range between 10 and 60 nm. Energy dispersive x-ray analysis confirmed the elemental composition of the synthesized nanoparticles, with Ag and Zn elements detected in their respective samples. It also confirmed the oxide nature of synthesized ZnNPs. Dynamic light scattering analysis provided size distribution profiles, indicating average sizes of approximately 61.8 nm for Ag nanoparticles and 46.5 nm for Zn nanoparticles. The concentrations of Ag and Zn nanoparticles in the samples were found to be 196.3 ppm and 115.14 ppm, respectively, through atomic absorption spectroscopic analysis. Fourier transform infrared spectroscopy analysis revealed characteristic functional groups present in the nanoparticles. The results of field experiments established that Ag nanoparticles at 75 ppm concentration exhibited the most significant enhancements in plant growth. Conversely, Zn nanoparticles at a 100 ppm concentration demonstrated the most substantial improvements in the growth and yield of heat-stressed wheat varieties. The study concludes that optimized concentrations of silver and zinc nanoparticles can effectively improve heat stress resilience in wheat. These findings are promising to enhance abiotic stress resilience in crops.
Laser-Induced Periodic Nanoripples Generation on Gallium Nitride Using Near-infrared Ultrashort Pulsed Laser
Authors: Yulianto Nursidik , Titok Sugiarto Iyon , Panji Tresna Wildan , Suwardy Joko , Majid Nurhalis , Herbani Yuliati , Isnaeni  , Anggoro Ardy Nugroho Ferry
Published: February 2024

Laser-induced periodic surface structure (LIPSS), or nanoripples, is a fascinating laser-induced surface morphology observed on a wide range of solid-state materials, with many potential applications in surface engineering, photonics, and optoelectronic devices. On the specific material of gallium nitride (GaN), the well-known formation mechanism and the potential applications of LIPSS are still being explored. Here, a near-infrared spectra of an ultrashort pulsed laser were used to generate periodic nanostructures with dimensions smaller than the laser wavelength on the surface of a GaN LED. From the result, the LIPSS maintained the direction equivalent to the GaN surface, with periodicity around 140–220 nm perpendicular to <1–100> substrate orientation. Finally, the advances in fabrication of LIPSS are presented as a potential nanograting for increasing the efficiency of LED-based GaN.
Q-switched Erbium Doped Fiber Laser Generation Using the Kerr Effect of Multimode Interference
Authors: Chen Yu , Dimyati Kaharudin , Wadi Harun Sulaiman
Published: February 2024

This work demonstrates a single mode fibre-step index multimode fibre-single mode fibre (SMS) structure as saturable absorber (SA) to generate Q-switched laser based on the Kerr-effect of multimode interference (MMI) in an Erbium-doped fibre laser (EDFL) cavity. A 156 mm length of step index multimode fibre (SIMF) was spliced directly into a ring cavity to modulate the cavity loss. By bending and applying proper pressure on the SIMF, steady Q-switched pulse was generated without strict length restriction of the SIMF. The Q-switched laser had a high repetition rate from 87 to 158 kHz, while the corresponding pulse width was low, ranging from 4.2 μs to 2.5 μs as the pump power increased from 115 to 342 mW. The signal-to-noise ratio (SNR) of the fundamental mode for the pulsed laser was about 67 dB at a central wavelength of 1530 nm. The experiment demonstrated that SMS structure can be used as stable SA to generate Q-switched laser for high power applications. It also indicated that even with large core diameter step index multimode fiber, SMS structure can be utilized to generate stable Q-switched pulsed laser with very simple cavity settings.
All-fiberized amorphous carbon nitride (a-CNx) based passive Q-switcher
Authors: Nur Fatin Zuikafly Siti , Jazair Yahya Wira , Awang Rozidawati , Yahaya Hafizal , Haniff Ibrahim Mohd , Ahmad Fauzan
Published: February 2024

This research presents the first-ever demonstration of a passively Q-switched fiber laser in the 1.5 μm wavelength region using amorphous carbon nitride (a-CNx) as a saturable absorber (SA) in an all-fiber configuration. The a-CNx thin film was prepared using plasma-enhanced chemical vapor deposition. The laser operation showed remarkable stability, achieving a repetition rate of 57.99 kHz and a pulse duration of 1.36 μs at maximum input pump power. The peak power and pulse energy reached 100.56 mW and 136.77 nJ, respectively. The utilization of a-CNx as an SA offers potential benefits such as a simpler and more flexible cavity design, making it an attractive candidate for various applications, including material processing and medical laser equipment. This work contributes to the advancement of fiber lasers and expands the possibilities for utilizing carbon nitride-based SAs in practical laser systems.
Soliton Pulse Generation with MoS2 Saturable Absorber
Authors: Wadi Nurul Izzah S. , Ahmad Aeriyn D. , Jusoh Zulzilawati
Published: February 2024

We have successfully generated soliton mode-locked pulses in a ring Erbium-doped fiber laser (EDFL) cavity using molybdenum disulfide (MoS2) saturable absorber. The MoS2 thin film was grown onto ITO substrate through electro-deposition process using a mixture of 0.5M H2MoO4 and 0.5M Na2S2O3.5H2O as electrolyte solution. The EDFL produced stable soliton pulses operating at centre wavelength of 1557 nm and repetition rate of 1.88 MHz. The mode-locking was realized by injecting pump power within a range from 77 mW to 124 mW. It generates the maximum output power of 0.7 mW and pulse width of 3.0 ps.
Performance Analysis of Zinc Cobaltite (ZnCO2O4) As A Hole Transport Layer (HTL) For Perovskite Solar Cell Using OghmaNano Software and Taguchi Method Optimization.
Authors: Rummaja I D , Idris M I , Napiah Z A F M , Zamani Z B , Ramlee R H , Rashid M
Published: February 2024

Perovskite solar cells (PSCs) are cost-effective and efficient photovoltaic cells that show great potential as an alternative to silicon solar cells. They possess desirable properties such as high mobility, direct bandgap, long carrier lifetime, and strong light absorption. However, the traditional materials used for the holes transport layer (HTL) in PSCs, such as PEDOT:PSS, SPIRO-OMETAD, and copper(I) iodide, have durability issues and lower carrier mobility. To overcome these challenges, Zinc Cobaltite (ZnCO2O4) with its advantages of hole transport, wide optical bandgap, and solution processability was investigated as a potential alternative HTL material. Through simulations using OghmaNano software and the Taguchi method, the device structure FTO/TiO2/CsPbI3/ZnCO2O4/Au was analyzed, and the performance was optimized by varying the thickness of the ZnCO2O4 layer. The simulation results showed a power conversion efficiency (PCE) of 32.23% with a ZnCO2O4 thickness of 300nm. ANOVA analysis revealed that the ZnCO2O4 thickness as the HTL had the most significant influence on PCE, followed by environmental temperature and the bandgap of ZnCO2O4. In particular, the ZnCO2O4 thickness had a substantial 70% impact on PCE, indicating that adjusting the thickness of ZnCO2O4 could lead to corresponding improvements in PCE.
Application of rice husk as a carbon source for substitution of sensitizer and counter electrode material in dye-sensitized solar cells
Authors: Paramitha T , Munika D A , Saputra D R , Nisa S S , Purwanto A , Supriyanto A , Widiyandari H , Aliwarga H K
Published: February 2024

The third generation of solar cells is dye-sensitized solar cells (DSSC). DSSC can convert solar energy into electrical energy. The main components of DSSC include working electrode, counter electrode, sensitizer, and electrolyte. Substitution of commercial chemicals for the sensitizer (N719) and the counter electrode (platinum) of DSSC will lower the cost of DSSC fabrication. This study focuses on Nitrogen-Doped Carbon Quantum Dots (N-CQDs) synthesized from rice husks as a sensitizer. Then, DSSC with sensitizer of N719 (Pt-1) and N-CQDs (Pt-2) were compared. Furthermore, the N-CQDs residue in solid carbon was used as the counter electrode material using different sensitizers N719 (C-1) and N-CQDs (C-2). Based on the results, the FTIR characterization of N-CQDs showed the functional groups N-H, O-H, C=O, and CN. The UV-VIS characterization of N-CQDs had absorbance in the wavelength range of 200-400 nm. Pt-2 has an efficiency value of 0.258%, Jsc of 2.188 mA/cm2 Voc of 0.6 volts, and FF of 0.20. C-2 has an efficiency of 0.0010%, Jsc of 0.042 mA/cm2 Voc of 0.131 volts, and FF of 0.17. This confirms that N-CQDs can be used as a sensitizer and counter electrode material, although the results are not as good as commercial chemicals.
Fast prediction of a high directivity antenna characterization for future wireless communication based on terahertz photonics
Authors: Arisesa Hana , Nur Wijayanto Yusuf , Adhi Purwoko , Iqbal Farabi , Idrus Sevia M.
Published: February 2024

Fast prediction of high-directivity antenna characterization has been presented. The Cassegrain antenna working at J band frequency has been evaluated using a terahertz (THz) photonic system based on near-field measurement. The generation and detection of THz signal are based on a non-polarimetric electrooptic (EO) frequency down-conversion technique combined with a self-heterodyne system. The synthesis method is introduced to estimate far-field E and H-plane antenna characteristics. The antenna result is calculated using amplitude and phase-synthesized data based on the measured data. A near-field (NF) to far-field (FF) transformation is employed in the antenna radiation pattern. The effect of blocking objects on the antenna (supporting rods and sub-reflector) is discussed. The antenna characteristics of the measured and synthesized data are compared to the ITU F.699 recommendation. The synthesized result agrees with the measured one on the main lobe angle.
Detection of Envelope Glycoprotein Domain III (ED III) Based on Surface-Enhanced Raman Scattering for Dengue Diagnosis
Authors: Novaznursyah Costrada Aldo , Felicia  , Siti Aminah Nina , Fitriyah Masduki Fifi , Herman  , Natalia Dessy , Djamal Mitra
Published: February 2024

Surface-enhanced Raman Scattering (SERS) based ED III protein detection has been conducted as a dengue virus diagnosis. ED III is one of the ectodomains of the envelope located along the surface of the dengue virus and acts as a receptor for the virus with its host cells. The SERS substrate used in this study is On-Spec-lite SERS by NECTEC and fabricated as a grating surface coated with gold. The imaging results from SEM show that the average radius of gold nanoparticles on OnSpec-lite SERS is 60 nm. On the grating-Au surface, the grating period is 588 nm with 50 nm thickness of gold thin film. OnSpec-lite SERS has a more significant increase in Raman intensity than the grating-Au surface when detecting ED III using Raman spectroscopy. The amino acids in the ED III Raman bands are Glycine, Alanine, Histidine, and Proline. The highest intensity Raman band that appears is 850 cm-1. Based on the research done in dengue virus detection, ED III has a typical Raman peak of 850 cm-1 which is the Raman band of Glycine and Alanine with CCN symmetry stretching vibration mode (𝑣(CCN)). This distinctive characteristic of ED III can be used as a diagnostic to detect dengue virus.
Optimization of Semiconductor-Based SRR Metamaterials as Sensors
Authors: Soerbakti Yan , Saktioto  , Sulistyo Rini Ari , Astuti Budi , Syamsudhuha  , Anita Sofia , Suyanto Hery , Rati Yolanda
Published: February 2024

The development of hybrid sensor media is needed to achieve more efficient, sensitive, and accurate performance. Efforts to modify the structure of conventional metamaterials are carried out by integrating semiconductor materials which aim to improve the characteristics of optical properties, electrical properties, and sensitivity as sensors. This study aims to analyze and investigate changes in the optical properties of semiconductor-based metamaterials. The research was conducted through simulation and numerical methods to design and characterize the SRR metamaterial geometry, with a modified Nicolson-Ross-Weir approach, especially the optical parameters of refractive index. The single-cell square pattern SRR metamaterial geometry with a ring radius of 2.2 – 2.8 mm on quartz glass substrate designed at a smaller wavelength based on a maximum frequency source of 9 GHz. The square SRR metamaterial is integrated with several semiconductor materials such as silicon (Si), gallium arsenide (GaAs), and aluminum nitride (AlN). Changes in radius size cause a redshift with respect to radius enlargement. The increasing ring radius of SRR causes a higher resonance depth of the refractive index. Combining hybrid semiconductors with metamaterial results in more negative metamaterial properties as the refractive index becomes larger and negative. The addition of semiconductor material to the metamaterial substrate causes a negative refractive index to shift to a lower frequency.
Photoacoustic Imaging using Diode Laser for Soft Tissue Visualization
Authors: Tasmara Fikhri A. , Wahyuni Eka , Silalahi Harry M. , Widyaningrum R , Setiawan A , Mitrayana
Published: February 2024

This study aimed to develop a photoacoustic imaging system using a diode laser as a radiation source, and a condenser microphone as a soft-tissue image detector. These tools were set in a static position and combined with the mechanic component to move the object table in the X-Y direction and were controlled by a computer with a LabView program. The result showed the built photoacoustic imaging system was used to analyze soft tissue using a diode laser in the frequency range of over 15 kHz with a 24%-47% duty cycle modulation. Furthermore, the minimum shift of the mechanic component X-Y stage was 0.02 mm, the sampling data rate was 1 second/pixel, and the image showed soft tissue intensity is generally higher than non-biological materials.
The relative class number one problem for function fields, III
Authors: Kedlaya Kiran
Published: February 2024

We complete the solution of the relative class number one problem for function fields of curves over finite fields. Using work from two earlier papers, this reduces to finding all function fields of genus 6 or 7 over

F

2

\mathbb {F}_2

with one of 40 prescribed Weil polynomials; one may then verify directly that three of these fields admit an everywhere unramified quadratic extension with trivial relative class group. The search is carried out by carefully enumerating curves based on the Brill–Noether stratification of the moduli spaces of curves in these genera, and particularly Mukai’s descriptions of the open strata.
Computing the endomorphism ring of an elliptic curve over a number field
Authors: Cremona John , Sutherland Andrew
Published: February 2024

We describe deterministic and probabilistic algorithms to determine whether or not a given monic irreducible polynomial

H
∈

Z

[
X
]

H\in \mathbb {Z}[X]

is a Hilbert class polynomial, and if so, which one. These algorithms can be used to determine whether a given algebraic integer is the

j
j

-invariant of an elliptic curve with complex multiplication (CM), and if so, the associated CM discriminant. More generally, given an elliptic curve 

E
E

over a number field, one can use them to compute the endomorphism ring of

E
E

. Our algorithms admit simple implementations that are asymptotically and practically faster than previous approaches.
Serre curves relative to obstructions modulo 2
Authors: Mayle Jacob , Rakvi
Published: February 2024

We consider elliptic curves

E

/

Q

E / \mathbb {Q}

for which the image of the adelic Galois representation

ρ
E

\rho _E

is as large as possible given a constraint on the image modulo 2. For such curves, we give a characterization in terms of their

ℓ
\ell

-adic images, compute all examples of conductor at most 500,000, precisely describe the image of

ρ
E

\rho _E

, and offer an application to the cyclicity problem. In this way, we generalize some foundational results on Serre curves.