bluuebunny/crossref_metadata_2025 huggingface dataset:
Pediatric Diabetes on the Rise: Trends in Incident Diabetes During the COVID-19 Pandemic
Authors: Modarelli Rachel , Sarah Salma , Ramaker Megan E , Bolobiongo Mboli , Benjamin Robert , Gumus Balikcioglu Pinar
Published: February 2022

Context

The effects of the coronavirus disease 2019 (COVID-19) pandemic on the incident cases of pediatric type 1 diabetes (T1D) and type 2 diabetes (T2D) are not clear.

Objective

To identify trends in incidence and presentation of pediatric new-onset T1D and T2D during the COVID-19 pandemic.

Methods

A retrospective chart review was conducted. Demographics, anthropometrics, and initial laboratory results from patients ages 0 through 21 years who presented with new-onset diabetes to a pediatric tertiary care center were recorded.

Results

During the pandemic, incident cases of pediatric T1D increased from 31 in each of the prior 2 years to 46; an increase of 48%. Incident cases of pediatric T2D increased by 231% from 2019 to 2020. The number of incident cases of pediatric T2D increased significantly more than the number of incident cases of pediatric T1D (P = 0.009). Patients with T2D were more likely to present in diabetic ketoacidosis (DKA), though this was not statistically significant (P = 0.093). Severe DKA was higher compared with moderate DKA (P = 0.036) in incident cases of pediatric T2D. During the pandemic, for the first time, incident cases of T2D accounted for more than one-half of all newly diagnosed pediatric diabetes cases (53%).

Conclusions

There were more incident pediatric T1D and T2D cases as well as an increase in DKA severity in T2D at presentation during the COVID-19 pandemic. More importantly, incident T2D cases were higher than the incident T1D during the pandemic. This clearly suggests a disruption and change in the pediatric diabetes trends with profound individual and community health consequences.
Left Atrial Dissection Secondary to Retrograde Coronary Sinus Cannulation During a Stanford Acute Type-A Aortic Dissection Repair: A Case Report
Authors: Halline Christopher , Winegarner Andrew , Maslow Andrew , Gorgone Michelle
Published: February 2022

Left atrial (LA) dissections are rare phenomena, often iatrogenic, caused by blood flow into a false lumen, potentially obstructing the pulmonary veins or flow into the left ventricle. Severity can range from an incidental observation or complete circulatory collapse. While LA dissections are often associated with mitral valve repair, there are 2 reported cases of LA dissections associated with retrograde cardioplegia cannula insertion through the coronary sinus. Here, we present a large LA dissection that was directly visualized and tracked to a coronary sinus injury from the retrograde cardioplegia cannula. The clinical presentation and echocardiography findings informed our subsequent management.
Living Worth
Authors: Ecks Stefan
Published: February 2022

In Living Worth Stefan Ecks draws on ethnographic research on depression and antidepressant usage in India to develop a new theory of value. Framing depressive disorder as a problem of value, Ecks traces the myriad ways antidepressants come to have value, from their ability to help make one’s life worth living to the wealth they generate in the multibillion-dollar global pharmaceutical market. Through case studies that include analyses of the different valuation of generic and brand-name drugs, the origins of rising worldwide depression rates, and the marketing, prescription, and circulation of antidepressants, Ecks theorizes value as a process of biocommensuration. Biocommensurations—transactions that aim or claim to make life better—are those forms of social, medical, and corporate actions that allow value to be measured, exchanged, substituted, and redistributed. Ecks’s theory expands value beyond both a Marxist labor theory of value and a free market subjective theory, thereby offering new insights into how the value of lives and things become entangled under neoliberal capitalism.
Therapeutic potential of macrophage colony-stimulating factor in chronic liver disease
Authors: Keshvari Sahar , Genz Berit , Teakle Ngari , Caruso Melanie , Cestari Michelle F. , Patkar Omkar L. , Tse Brian W. C. , Sokolowski Kamil A. , Ebersbach Hilmar , Jascur Julia , MacDonald Kelli P. A. , Miller Gregory , Ramm Grant A. , Pettit Allison R. , Clouston Andrew D. , Powell Elizabeth E. , Hume David A. , Irvine Katharine M.
Published: February 2022

Resident and recruited macrophages control the development and proliferation of the liver. We have previously shown in multiple species that treatment with a macrophage colony stimulating factor (CSF1)-Fc fusion protein initiated hepatocyte proliferation and promoted repair in models of acute hepatic injury in mice. Here, we investigated the impact of CSF1-Fc on resolution of advanced fibrosis and liver regeneration, using a non-resolving toxin-induced model of chronic liver injury and fibrosis in C57BL/6J mice. Co-administration of CSF1-Fc with exposure to thioacetamide (TAA) exacerbated inflammation consistent with monocyte contributions to initiation of pathology. After removal of TAA, either acute or chronic CSF1-Fc treatment promoted liver growth, prevented progression and promoted resolution of fibrosis. Acute CSF1-Fc treatment was also anti-fibrotic and pro-regenerative in a model of partial hepatectomy in mice with established fibrosis. The beneficial impacts of CSF1-Fc treatment were associated with monocyte-macrophage recruitment and increased expression of remodelling enzymes and growth factors. These studies indicate that CSF1-dependent macrophages contribute to both initiation and resolution of fibrotic injury and that CSF1-Fc has therapeutic potential in human liver disease.
Appearance of an Electrochemical Oxidative Peak of Gold/Bis(trifluoromethylsulfonyl)amide-based Ionic Liquid Interfaces at Elevated Temperatures
Authors: Ueda Hiroyuki , Hisatomi Tomohiro , Yoshimoto Soichiro
Published: February 2022

The electrochemical behavior of a Au(111) electrode was investigated in three ionic liquids (ILs) containing trifluoromethylsulfonyl-based anions at temperatures ranging from 20 °C to 100 °C. Gold oxidation, that is, gold etching, occurred at elevated temperatures (≥70 °C) and was found to be dependent on the chemical structure of the ILs. These results allow us to simplify the procedure of gold dissolution in bis(trifluoromethylsulfonyl)amide-based ILs, thereby improving the efficiency of electrochemical etching.
Heteroatom-incorporated Trimethylenemethane: Synthesis and Properties of Triphenylphenylnitroxide–(Nitronyl Nitroxide) Dyad
Authors: Kumagai Tasuku , Suzuki Shuichi , Kanzaki Yuki , Shiomi Daisuke , Sato Kazunobu , Takui Takeji , Tanaka Rika , Okada Keiji , Kozaki Masatoshi
Published: February 2022

We designed and synthesized a triphenylphenylnitroxide–(nitronyl nitroxide) dyad with a structure isoelectronic with trimethylenemethane. Crystal structure analysis demonstrated that the dihedral angle between the nitroxide and nitronyl nitroxide moieties was excessively small due to the steric effects of the triphenylphenyl moiety. The coplanarity of the two radical systems induced an excessively strong ferromagnetic intramolecular interaction (2J/kB ≥ +2000 K; H = −2JS1/2•S1/2).
Speech impairment in Parkinson’s disease
Authors: Σπανού Αικατερίνη
Published: February 2022

Οι διαταραχές φωνής και ομιλίας είναι αρκετά συχνές σε ασθενείς που έχουν διαγνωστεί με νόσο του Πάρκινσον (PD). Οι στόχοι της παρούσας διατριβής ήταν: (i) να εξετάσει πως επηρεάζουν η ένταση και ο ρυθμός την παραγωγή ομιλίας σε ασθενείς με PD και να αναγνωρίσει δείκτες ομιλίας ευαίσθητους στην ανίχνευση αυτών των επιδράσεων με την πάροδο του χρόνου, (ii) να εξετάσει πως η εκτέλεση ταυτόχρονων ενεργειών επηρεάζει την παραγωγή φυσιολογικής και δυνατής ομιλίας σε ασθενείς με PD και (iii) να εξετάσει τη δυνατότητα εκτέλεσης ενός πιλοτικού προγράμματος αποκατάστασης 12 εβδομάδων που συνδυάζει την αποκατάσταση λόγου με άλλες αρχές αποκατάστασης. Η έρευνα διεξήχθη σε τρεις μελέτες και στρατολογήθηκαν διαφορετικά δείγματα για κάθε μελέτη. Όλοι οι συμμετέχοντες υποβλήθηκαν σε εξέταση των κινητικών τους ικανοτήτων και αξιολογήθηκε και η ομιλία τους. Και στις τρεις μελέτες, τα πρωτόκολλα αξιολόγησης ομιλίας περιελάμβαναν παρόμοιες διαδικασίες αξιολόγησης και ερεθίσματα, αλλά υπήρχαν διαφορές στις εργασίες διεγέρσεως ομιλίας και στους εξαγόμενους δείκτες ανάλογα με τον στόχο κάθε μελέτης. Τα αποτελέσματα δείχνουν ότι η χειραγώγηση της έντασης έχει θετική επίδραση στην ομιλία στην PD, όπως ανιχνεύεται στην ένταση, και στους δείκτες φωνηέντων και συμφώνων που υπολογίζονται από μία εργασία πρόκλησης (ανάγνωση). Η δεύτερη μελέτη δείχνει ότι η ταυτόχρονη απόδοση επηρεάζει τα χρονικά χαρακτηριστικά ομιλίας, την ένταση της φωνής και την άρθρωση της ομιλίας, ενώ η διέγερση της έντασης υπερισχύει των επιπτώσεων της ταυτόχρονης κινητικής εργασίας. Τέλος, η τρίτη πειραματική μελέτη δείχνει ότι η πιλοτική εφαρμογή ενός προγράμματος ομαδικής αποκατάστασης, που συνδυάζει αρχές ομιλίας και φυσιοθεραπείας, είναι εφικτή και βελτιώνει την ομιλία και την κίνηση έως και τέσσερις μήνες μετά την εφαρμογή.
Do something or do nothing? anatomical variants and incidental findings on cone beam CT. part 1
Authors: Makdissi Jimmy , Loughlin Amanda , Dungarwalla Mohammed M
Published: February 2022

Cone beam computed tomography (CBCT) is a popular and often indispensable imaging modality used for the dento-alveolar tissues and immediate surrounding structures. It can be used across several dental disciplines including endodontics, implant planning, oral surgery and orthodontics. Furthermore, it is also commonly used in the medical specialities of oral and maxillofacial surgery (OMFS) and ear, nose and throat (ENT) surgery. In many of the images taken, there will often be findings/presentations that may not be expected, or familiar, to the reporting clinician.

CPD/Clinical Relevance: Many incidental findings are innocuous, yet their recognition and documentation are essential because some will warrant medical or surgical intervention.
Total and partial knee arthroplasty implants that maintain native load transfer in the tibia
Authors: Munford Maxwell J. , Stoddart Jennifer C. , Liddle Alexander D. , Cobb Justin P. , Jeffers Jonathan R. T.
Published: February 2022

Aims

Unicompartmental and total knee arthroplasty (UKA and TKA) are successful treatments for osteoarthritis, but the solid metal implants disrupt the natural distribution of stress and strain which can lead to bone loss over time. This generates problems if the implant needs to be revised. This study investigates whether titanium lattice UKA and TKA implants can maintain natural load transfer in the proximal tibia.

Methods

In a cadaveric model, UKA and TKA procedures were performed on eight fresh-frozen knee specimens, using conventional (solid) and titanium lattice tibial implants. Stress at the bone-implant interfaces were measured and compared to the native knee.

Results

Titanium lattice implants were able to restore the mechanical environment of the native tibia for both UKA and TKA designs. Maximum stress at the bone-implant interface ranged from 1.2 MPa to 3.3 MPa compared with 1.3 MPa to 2.7 MPa for the native tibia. The conventional solid UKA and TKA implants reduced the maximum stress in the bone by a factor of 10 and caused > 70% of bone surface area to be underloaded compared to the native tibia.

Conclusion

Titanium lattice implants maintained the natural mechanical loading in the proximal tibia after UKA and TKA, but conventional solid implants did not. This is an exciting first step towards implants that maintain bone health, but such implants also have to meet fatigue and micromotion criteria to be clinically viable. Cite this article: Bone Joint Res 2022;11(2):91–101.
Pulse-to-pulse relative intensity noise measurements for ultrafast lasers
Authors: Smith Callum R. , Engelsholm Rasmus Dybbro , Bang Ole
Published: February 2022

Relative intensity noise (RIN) can be used to characterize pulse-to-pulse energy variations of ultrafast lasers, and is a very important performance parameter when considering the suitability of a laser for an application. However, owing to a wide range of measurement and analysis techniques, comparison of RIN values is non-trivial. Here, we clearly layout a definition of RIN as a percentage value for ultrafast laser systems. Furthermore, we analytically describe how the RIN can be measured in the time and frequency domains, and reveal the conditions under which these two widely employed approaches are equivalent. Finally, we experimentally measure the RIN of an ultrafast supercontinuum laser to be 6.57% in the time domain and 6.98% in the frequency domain at 850 nm, and 17.06% in the time domain and 17.08% in the frequency domain at 1000 nm, thus demonstrating the expected strong agreement when the measurements and signal processing are performed appropriately.
Biological SERS-active sensor platform based on flexible silk fibroin film and gold nanoislands
Authors: Choi Ji Hyeon , Choi Munsik , Ho Tien Son , Kim Soogeun , Choi Samjin , Choi Seung Ho , Byun Kyung Min
Published: February 2022

In contrast to conventional surface-enhanced Raman scattering (SERS) platforms implemented on non-biological substrates, silk fibroin has the unique advantages of long-term biosafety and controllable biodegradability for in vitro and in vivo biomedical applications, as well as flexibility and process-compatibility. In this study, a silk fibroin film was developed to fabricate a flexible SERS sensor template with nanogap-rich gold nanoislands. The proposed biological SERS platform presents fairly good enhancements in detection performance such as detection limit, sensitivity, and signal-to-noise ratio. In particular, the sensitivity improvement was by more than 10 times compared to that of the counterpart sample, and an excellent spatial reproducibility of 2.8% was achieved. In addition, the near-field calculation results were consistent with the experimental results, and the effect of surface roughness of the silk substrate was investigated in a quantitative way. It is believed that biological SERS-active sensors could provide the potential for highly sensitive, cost-effective, and easily customizable nanophotonic platforms that include new capabilities for future healthcare devices.
Genetic architecture of variation in Arabidopsis thaliana rosettes
Authors: Morón-García Odín , Garzón-Martínez Gina A. , Martínez-Martín M. J. Pilar , Brook Jason , Corke Fiona M. K. , Doonan John H. , Camargo Rodríguez Anyela V.
Published: February 2022

Rosette morphology across Arabidopsis accessions exhibits considerable variation. Here we report a high-throughput phenotyping approach based on automatic image analysis to quantify rosette shape and dissect the underlying genetic architecture. Shape measurements of the rosettes in a core set of Recombinant Inbred Lines from an advanced mapping population (Multiparent Advanced Generation Inter-Cross or MAGIC) derived from inter-crossing 19 natural accessions. Image acquisition and analysis was scaled to extract geometric descriptors from time stamped images of growing rosettes. Shape analyses revealed heritable morphological variation at early juvenile stages and QTL mapping resulted in over 116 chromosomal regions associated with trait variation within the population. Many QTL linked to variation in shape were located near genes related to hormonal signalling and signal transduction pathways while others are involved in shade avoidance and transition to flowering. Our results suggest rosette shape arises from modular integration of sub-organ morphologies and can be considered a functional trait subjected to selective pressures of subsequent morphological traits. On an applied aspect, QTLs found will be candidates for further research on plant architecture.
Rendszerszintű átalakulás helyett szakpolitikai reform? – A részvételi akciókutatás társadalmat átalakító ereje és annak korlátai egy megyei jogú város deszegregációs szakpolitikájának tapasztalatain keresztül
Authors: Méreiné Berki Boglárka , Málovics György , Mihály Melinda
Published: February 2022

Az igazságosabb és ökológiailag fenntarthatóbb társadalmak előmozdítása érdekében alapjaiban kell átalakítanunk a jelenlegi társadalmi-gazdasági rendszert. A részvételi akciókutatás (RAK) nagy jelentőséget tulajdonít az „átalakulás” („transzformáció”) fogalmának, viszont közelebbről vizsgálva a kifejezés fogalmi és gyakorlati szempontból is nehezen megragadható. Pontosan mitől is lesznek a közpolitikák transzformatív jellegűek? A kérdés megválaszolásához először a transzformáció koncepcióját – mint az akciókutatás normatív társadalmi „ideája” – operacionalizáljuk, három fogalomkör segítségével: autonómia, képessé tétel és szolidaritás, bemutatva mindhárom hegemón (reformista) és alternatív (transzformatív) keretezését. E koncepciók segítségével azt igyekszünk megérteni, hogy a RAK-unk a helyi deszegregációs szakpolitikát és roma érdekérvényesítést inkább átalakította vagy megreformálta. Bemutatjuk, hogy miközben a roma képviselők RAK-unknak is köszönhetően egyre elfogadottabbá és befolyásosabbá váltak a helyi politikai életben, nem voltak képesek eltéríteni a városvezetést egy felülről lefelé vezényelt deszegregációs szakpolitikától. Így a deszegregációs folyamat narratívája és gyakorlata illeszkedik a neoliberális városfejlesztés logikájába – a RAK hatásai a transzformatív szándékok ellenére reformisták maradnak. Rámutatunk annak fontosságára, hogy részvételi akciókutatóként őszintén reflektáljunk azokra az elnyomó struktúrákra, amikben kutatásunk is zajlik, és aminek átalakítása nélkül RAK-unk csak reformista lehet – azaz nem nő fel a transzformatív ideához.
Vitamin D status of patients with systemic inflammatory connective tissue diseases: a cross-sectional study
Authors: Vilms E. A. , Dobrovolskaya E. V. , Turchaninova M. S. , Bykova E. A. , Sohoshko I. A.
Published: February 2022

Background. In addition to regulating mineral metabolism and bone metabolism, vitamin D is important for supporting structure and other types of connective tissue. Studies have shown the role of vitamin D deficiency in the pathogenesis of systemic inflammatory diseases of the connective tissue, autoimmune diseases. The results of studying this problem in countries with different geographic locations are also of interest.

Aim. Comparative assessment of vitamin D status of patients with systemic inflammatory diseases of the connective tissue and patients without rheumatic diseases.

Materials and methods. This cross-sectional observational study analyzed the vitamin D supply of the following groups: patients with systemic inflammatory diseases of the connective tissue who do not take vitamin D preparations, patients with systemic inflammatory diseases of the connective tissue who take vitamin D preparations, and «conditionally healthy» individuals, without complaints, examined in the same period comparable in gender and age with the patients of the main group. The vitamin D supply of the studied patients was determined by the level of the content of the vitamin D metabolite calcidiol in the blood serum 25 (OH) D. Study period: January 2019 to December 2020.

Results. The data of 625 patients who applied to the Osteoporosis Prevention and Treatment Center for the specified period were analyzed. Among the patients of the main group who did not take vitamin D preparations, a deficiency was revealed in 54.7% of the examined, the optimal provision in 11.2%. The median serum 25 (OH) D concentration was in the range of 19.0 ng / ml deficiency. The study participants belonging to the comparison group had a deficit in 44.1% of cases and an optimal provision in 21.5%. The study group of the main group receiving vitamin D preparations had the maximum number of individuals with the optimal status – 37.0%, while a significant part of the examined had a deficit of varying severity – 29.1%. In addition, this group was characterized by the highest median serum metabolite 25 (OH) D – 26.0 ng / ml.

Conclusion. A comparative analysis of the D-vitamin status of patients with systemic inflammatory diseases of the connective tissue and «conditionally healthy» individuals without complaints was carried out, which made it possible to establish differences in the provision depending on the existing disease, as well as depending on the therapy with vitamin D preparations. a lower supply of vitamin D than control group «healthy» individuals. In the case of receiving vitamin subsidies, the provision with it in the group of patients was statistically significantly higher, both in comparison with patients who did not take the vitamin, and in comparison, with individuals from the comparison group.
Funcionalidad familiar y rendimiento académico en estudiantes de ciencias de la salud: una revisión sistemática
Authors: Rocha Rodriguez Cecilia , Santiago Sarmiento Nurys , Borré-Ortiz Yeis Miguel
Published: February 2022

Objetivo: Identificar los factores de la funcionalidad familiar asociados al rendimiento académico de los estudiantes de ciencias de la salud a nivel de educación superior, según lo reportado en la literatura. Materiales y método: Se llevó a cabo una revisión sistemática de la literatura en las siguientes bases de datos: PubMed (MedLine), ProQuest, SciELO y Google Académico, utilizando descriptores clave, criterios de selección y límites de búsqueda durante el proceso de revisión. Veintitrés documentos fue el insumo final seleccionado para el análisis. Resultados: Adicional a los hallazgos descriptivos de los estudios, emergieron factores positivos y negativos que se constituyen en categorías explicativas de la asociación existente entre la funcionalidad familiar y el rendimiento académico en los estudiantes de ciencias de la salud en educación superior. Conclusión: La literatura científica sobre funcionalidad familiar y su asociación con el rendimiento académico en los estudiantes universitarios, aunque ha ido en aumento de forma significativa, se ha desarrollado desde perspectivas diversas. Se requiere mayor integración y estudios de investigación que incluyan a la familia y a la universidad como entornos próximos y de desarrollo de los estudiantes.
Relación entre sarcopenia y calidad de vida en personas mayores chilenas autovalentes y dependientes leves de dos ciudades del sur de Chile
Authors: Robles-Robles Matías , Yáñez-Yáñez Rodrigo , Cigarroa Igor
Published: February 2022

Introducción: La sarcopenia es la enfermedad muscular vinculada al proceso de envejecimiento y que se asocia a una disminución de la calidad de vida y la funcionalidad en las personas mayores. Objetivo: Determinar la asociación entre la sarcopenia y la calidad de vida de personas mayores autovalentes y dependientes leves de dos ciudades del sur de Chile. Metodología: El estudio tuvo un diseño no experimental, analítico y de temporalidad transversal. La muestra estuvo constituida por 80 personas mayores (30 hombres); se utilizó un muestreo no probabilístico por conveniencia. Para determinar la calidad de vida se aplicó la encuesta de calidad de vida SF-36, y para determinar sarcopenia se aplicó el flujograma del Grupo de Trabajo Europeo sobre Sarcopenia en Personas Mayores, que evalúa la fuerza muscular (dinamometría), masa muscular apendicular y rendimiento físico (velocidad de marcha). Resultados: La prevalencia de sarcopenia en las personas mayores alcanzó un 23,8 %. No se evidenció asociación entre la sarcopenia y calidad de vida. Al analizar los parámetros para evaluar la sarcopenia por separado, se evidenció una asociación entre la velocidad de marcha y las dimensiones de calidad de vida (función física; p=0,000, rol físico; p=0,005 y función social; p=0,010). Conclusión: Una menor velocidad de marcha se relacionó con una baja calidad de vida. Futuros programas de evaluación y control de la sarcopenia deberían considerar la calidad vida como una variable asociada al rendimiento físico de las personas mayores.
Political Theory of Nation-Building:Case of the Failed State of Afganistan in 2021: Part 1
Authors: Betz Frederick
Published: February 2022

Why is it important to get social science methodology correct? It is important because invalid social science theory may be used to formulate governmental policies which are wrong – incompetent and even harmful. A modern (and tragic) example of invalid social theory with bad policy is the case of America’s 20-year effort in ‘nation-building’ by occupying Afghanistan. In 2021, the policy ended dramatically with the rapid fall of the Afghan government and the triumph again of the Taliban. Afghanistan was a failed state, after a history of a series of invasions. In this research, we analyze the theory of nation-building, which can be verified by this historical event. The cross-disciplinary social science theory of nation-building is that it should be a two-directional process: with both up-and-down perspectives on building a nation from a state. This theory was analyzed empirically in a previous paper by the author, to explain the failure of nation-building in Lebanon. (Betz, 2020) Here we analyze use the theory of nation-building to explain a historical case of policy failure in Afghanistan. This theory of two strategic directions of nation-building, top-down and bottom-up, are validated in the histories of two different societies. Social science theory verified in two or more societal histories is likely to be generalizable to any modern society.
The Neukirch–Uchida theorem with restricted ramification
Authors: Shimizu Ryoji
Published: February 2022

Let K be a number field and S a set of primes of K.
We write

K
S

/
K

{K_{S}/K}

for the maximal extension of K
unramified outside S and

G

K
,
S

{G_{K,S}}

for its Galois group.
In this paper, we prove the following generalization of the Neukirch–Uchida theorem under some assumptions:
“For

i
=

1
,
2

{i=1,2}

, let

K
i

{K_{i}}

be a number field and

S
i

{S_{i}}

a set of primes of

K
i

{K_{i}}

. If

G

K
1

,

S
1

{G_{K_{1},S_{1}}}

and

G

K
2

,

S
2

{G_{K_{2},S_{2}}}

are isomorphic, then

K
1

{K_{1}}

and

K
2

{K_{2}}

are isomorphic.”
Here the main assumption is that the Dirichlet density of

S
i

{S_{i}}

is not zero for at least one i. A key step of the proof is to recover group-theoretically the l-adic cyclotomic character of an open subgroup of

G

K
,
S

{G_{K,S}}

for some prime number l.
Investigations on the Hardness and Grain Size of Gears made out of Ultra-Clean Gear Steels after Case-Hardening
Authors: Fuchs D. , Fiederling E. , Tobie T. , Stahl K.
Published: February 2022

Kurzfassung

Härte und Korngröße von Zahnrädern aus hochreinen Zahnradstählen nach Einsatzhärtung und Kugelstrahlen wurden im Rahmen eines Forschungsprojekts untersucht, dessen Schwerpunkt auf der Bestimmung der Zahnfußtragfähigkeit von einsatzgehärteten, kugelgestrahlten Zahnrädern lag. Die häufigste Versagensart bei diesen hochfesten Zahnrädern ist der Zahnfußbruch, der durch eine Rissinitiierung unterhalb der Oberfläche an einem nicht-metallischen Einschluss verursacht wird (Bruchlinsenversagen, im Englischen: Fisheye failure). Neben solchen Einschlüssen sind auch die Härte und die Abschreckkorngröße dafür bekannt, dass sie einen erheblichen Einfluss auf die Tragfähigkeit eines Zahnrades haben. Um sicherzustellen, dass in diesem Forschungsprojekt ausschließlich der Einfluss von nicht-metallischen Einschlüssen untersucht wird, mussten mögliche Quereinflüsse ausgeschlossen, minimiert oder zumindest bekannt sein. Nach einem ungeeigneten Einsatzhärtungsprozess erreichen Zahnräder jedoch nicht die härtebezogenen Spezifikationen, oder Zahnräder aus Zahnradstählen mit hoher Feinkornstabilität können Mengen an gröberen Körnern enthalten. Daher wurden Einsatzhärtungsparameter abgeleitet und überprüft, ob sie zu den für einsatzgehärtete Zahnradstähle geforderten Korngrößen- und Härtespezifikationen nach ISO 6336 führen. Weiterhin wurde untersucht, wie sich ein reduzierter Aluminiumgehalt bei resultierenden höheren Reinheitsgrad, d. h. kompensiert durch eine Nioblegierung zur Erhaltung der Feinkornstabilität, auf die Korngröße nach dem Einsatzhärten auswirkt.
Gearbox Production Using Distortion Controlled Inductive Fixture Hardening*
Authors: Knauf S. , Buchner K. , Jenne R.
Published: February 2022

Fixture-hardening, also known as quench-press hardening, is a widespread process mainly for the automotive industry. This paper introduces a new inductive hardening and tempering process that combines the well-known advantages of induction heating and hardening with the advantages of a fixture hardening process to obtain highly precise workpieces with enormously reduced or even without rework. The main component is a new hardening machine with implemented fixture hardening assembly and integrated induction coil, all in a protective gas atmosphere. Induction as electrical energy source can be used for heating up workpieces prior to fixture hardening and for tempering, which allows to simultaneously draw out the calibration mandrel without any abrasive wear on its surface. In certain applications, an expanding mandrel can be used in order to relieve the workpiece.
Synthesis of Nanocrystalline B2 Structured (Ru, Ir) Al in the Ternary Ru–Al–Ir System by Mechanical Alloying and its Thermal Stability
Authors: Liu K.W. , Mücklich F. , Pitschke W. , Birringer R. , Wetzig K.
Published: February 2022

B2 structured single-phase (Ru,Ir)Al is synthesized directly in the ternary Ru– Al– Ir system by mechanical alloying. Complete solubility between pseudo-binary RuAl – IrAl is achieved in a composition range 10–25 at.% Ir, while the range for Al remains at 50 at.%. B2 structured (Ru, Ir) Al is formed by an abrupt reaction at the beginning of milling of all three compositions and a certain quantity of Ir was found to remain after the reaction. Further alloying and a reaction between Ir and sticking Al on the surfaces of milling tools take a much longer time and finally result in single phase B2 structured (Ru, Ir) Al. The ternary alloying element Ir has been found to ameliorate the sluggish reactivity of Ru by promoting the abrupt reaction. No decomposition process has been observed for the as-milled single-phase (Ru, Ir) Al by means of high-temperature X-ray diffraction, demonstrating the complete mutual solubility between pseudo-binary RuAl and IrAl in the present composition range. The structural evolution of as-milled materials includes reordering, strain relaxation and grain growth. The grain size of the as-milled (Ru, Ir) Al after exposure to elevated temperatures (up to 1273 K), turns out to be less than 30 nm and reflects its strong thermal stability.
The Al–Ca System, Part 2: Calorimetrie Measurements and Thermodynamic Assessment
Authors: Kevorkov D. , Schmid-Fetzer R. , Pisch A. , Hodaj F. , Colinet C.
Published: February 2022

Drop solution calorimetry was performed to determine the enthalpies of formation of the binary Al2Ca and Al3Ca8 phases and the partial enthalpy of mixing at infinite dilution of calcium in liquid aluminum. A consistent thermodynamic model of the Al–Ca system was constructed for the four stoichiometric compounds Al4Ca, Al2Ca, AlCa and Al3Ca8 and for the liquid phase with a sub-subregular solution model. Optimization of the thermodynamic parameters using the Calphad method was done by incorporating all available experimental data on phase equilibria, enthalpies of formation and mixing and the activity coefficients in the liquid. A consistent description of the phase diagram and thermodynamic properties is presented which is well supported by the experimental data. The Ca-rich part of the phase diagram differs substantially from previous reports, mainly because of the two newly discovered phases AlCa and Al3Ca8.
Interface Motion of β-Silicon Nitride in a Liquid Phase
Authors: Wang Ling-Ling , Tien Tseng-Ying
Published: February 2022

Morphology evolution of β-Si3N4 grains on the end caps has shown significant dynamical features. It has been observed the (0001) growth front experiencing a shape transition on the caps from semisphere to negative-curved configuration. After our previous simplified solution, in this paper, the finite element analysis method has been used to further simulate the tip evolution for the hexagonal β-Si3N4 grains.
Characterization of the metastable austenite in low-alloy FeCMnSi TRIP-aided steel by neutron diffraction
Authors: Barbé L. , Conlon K. , De Cooman B.C.
Published: February 2022

The detailed analysis of X-ray diffraction data obtained from intercritically annealed and isothermally transformed low-alloy FeCMnSi TRIP-aided steels reveals that the microstructure contains athermal plate martensite and Fe2C η carbide in addition to ferrite, bainite and residual austenite. Neutron diffraction shows that athermal plate martensite can be formed at room temperature in the isolated austenite phase. Whereas the formation of athermal martensite leads to compressive strains in the austenite, the formation of strain-induced martensite results in tensile straining of the austenite. The strain-induced transformation leads to the formation of a martensite of low tetragonality. Low-temperature annealing leads to the formation of η carbide in both the athermal and strain-induced martensite.
Strain softening effects in texture and microstructure of torsioned pre-deformed Al rods
Authors: Kuśnierz J. , Kurowski M.
Published: February 2022

The strain softening effect is exemplified on Al rods (99.8 wt.% purity) torsioned after pre-deformation by rolling, where that effect is most distinct. Observations of thin foils in Al rods, parallel to cross – sectional plane as well as along longitudinal section, were carried out on samples deformed up to the shear deformation φ = 0.645, i. e., near the end of the stress softening range, and on samples deformed up to the shear deformation φ = 5.193, i. e., near the maximum of the strain hardening range. In the strain softening range we have noted: (a) a decrease in dislocation density in the grain interior and in the grain boundary, and (b) formation of a strong (001)[110] shear texture component. Growing dislocation density and formation of axial ⟨111⟩+⟨100⟩ texture components were observed during torsion in the strain hardening range.
Wear behaviour of graphitic aluminium composite sliding under dry conditions
Authors: Mohan S. , Pathak J. P. , Gupta R. C. , Srivastava S.
Published: February 2022

A modified mixing and casting procedure was used for the preparation of Al-1.2 Si-0.8 Fe–Gr composite (wt.%). Graphite and gray cast iron powders were blended and dispersed in Al-1.2 Si matrix alloy melt and poured in a cast iron mould. Gray cast iron powder worked as carrier for graphite particles. The presence of graphite improves the ultimate tensile strength, tensile and compressive stress but beyond 1 % of graphite all properties deteriorate. However, hardness continuously increases and percentage elongation reduces with graphite. In wear studies, different mechanisms: mild-oxidative, oxidative-metallic and severe-metallic, are operative in the different combinations of sliding velocities and applied loads.
Thermally assisted motion of dislocations in solid solution-strengthened fcc alloys and the concept of “stress equivalence”
Authors: Argon Ali S.
Published: February 2022

It is demonstrated that relatively well established developments of the collective interactions of moderately concentrated solute atoms with a dislocation can furnish a satisfactory model for the thermally assisted motion of dislocations through such solute fields and provide insight into the concept of “stress equivalence” exhibited by binary fcc alloys. This is consistent with known dependencies of the plastic shear resistance on temperature and the universal dependence of the activation volume on flow stress alone, for a large family of binary fcc alloys of different solute concentration. Both the successful features of the model and some of its shortcomings are discussed.
Influence of dissolved gas molecules on the size recovery kinetics of cold-rolled BPA-PC
Authors: Tarasewich John , Pekarski Pavel , Kirchheim Reiner
Published: February 2022

Besides annealing, plastic strain in a polymer can also be released partly during the sorption of a small molecule like CO2 as reported for the first time in this study. The corresponding size recovery is measured for the glassy polymer Bisphenol-A-polycarbonate in situ in a dilatometer. The plastic strain was introduced into the polymer by cold rolling with a 17% reduction in cross-section and it was observed that the strain relaxation is anisotropic, i. e., being the largest in the rolling direction.
The grain boundary hardness in austenitic stainless steels studied by nanoindentations
Authors: Schweitzer Elmar , Göken Mathias
Published: February 2022

The strength of structural materials depends strongly on the structure and properties of grain boundaries. Grain boundaries in crystalline solids are internal surfaces and therefore likely sites for nucleation of precipitates and segregation effects. Nanoindentations are a suitable method to study the influence of grain boundaries on the mechanical properties. The necessary lateral resolution is achieved by combining with an atomic force microscope. Measurements on an austenitic steel after annealing at 650 °C, where the boundary is saturated with carbide precipitates, clearly show a decreasing hardness close to the interface in opposite to the general expected behaviour of strengthening. In this case segregation effects strongly influences the mechanical properties around the boundaries. These results are discussed in comparison with nanoindentation measurements on strongly ordered intermetallics like NiAl where no significant property change at the boundaries was found and with Vickers hardness measurements by Westbrook et al., where a higher grain boundary hardness was found in many metallic and intermetallic materials depending on their composition.
On the determination of the volume fraction of Ni4Ti3 precipitates in binary Ni-rich NiTi shape memory alloys
Authors: Dlouhý Antonín , Khalil-Allafi Jafar , Eggeler Gunther
Published: February 2022

The size distributions and volume fractions of Ni4Ti3 precipitates in Ni-rich Ni –Ti shape memory alloys affect their mechanical and functional properties. In the present work precipitate sizes and volume fractions were measured after various thermo-mechanical treatments using transmission electron microscopy (TEM) in combination with quantitative metallography. TEM tilting experiments revealed that the Ni4Ti3 particles have a disk-like shape with a disk diameter D and a disk thickness t. These two parameters together with the number density of particles per unit volume were determined after stress-free and stress-assisted aging at 400, 500 and 530 °C. Volume fraction results are presented after different thermo-mechanical treatments and our quantitative metallographic procedure is documented.
Diffraction by image processing and its application in materials science
Authors: Ohser Joachim , Schladitz Katja , Koch Karsten , Nöthe Michael
Published: February 2022

A spectral theory for constituents of macroscopically homogeneous random microstructures is developed and provided with a sound mathematical basis, where the spectrum obtained by Fourier methods corresponds to the angular intensity distribution of X-rays scattered by this constituent. It is shown that the fast Fourier transform applied to three-dimensional images of microstructures obtained by micro-tomography is a powerful tool of image processing. The applicability of this technique is demonstrated in the analysis of images of porous media.
Boron segregation and creep in ultra-fine grained tempered martensite ferritic steels
Authors: Eggeler G. , Dlouhy A.
Published: February 2022

The creep strength of ultra-fine grained tempered martensite ferritic steels with 9 to 12 wt.% chromium is significantly increased when small amounts of boron (in the 100 wt-ppm regime) are added. In the present note, experimental evidence from the literature is reviewed and previous explanations for the role of boron are summarized. The explanation for the effect of boron on creep strength must leave space for the simultaneous effect of boron on ductility. A scenario is suggested where boron segregates to micrograin boundaries which often have subgrain-boundary character. Boron can decrease the subgrain-boundary energy, decrease the velocity of subgrain-boundary migration, hinder knitting reactions between free dislocations and subgrain-boundaries and thus contribute to creep strength. This decrease of intensity of interface plasticity contributes to a decrease in ductility. Boron may moreover decrease the strength of the interface and thus promote brittleness. Further work is required to fully account for the role of boron on the mechanical properties of tempered martensite ferritic steels.
Effect of interface strength on electromigration-induced inlaid copper interconnect degradation: Experiment and simulation
Authors: Zschech Ehrenfried , Engelmann Hans-Jürgen , Meyer Moritz Andreas , Kahlert Volker , Vairagar Anand V. , Mhaisalkar Subodh G. , Krishnamoorthy Ahila , Yan Minyu , Tu K. N. , Sukharev Valeriy
Published: February 2022

Both in situ microscopy experiments at embedded inlaid copper interconnect structures and numerical simulations based on a physical model provide information about electromigration-induced degradation mechanisms in on-chip interconnects. It is shown that the modification of the bonding strength of the weakest interface results in completely changed degradation and failure mechanisms. Transmission electron microscopy (TEM) images of standard Cu/SiNxinterfaces are compared with strengthened interfaces, e. g., after applying an additional metal coating or a self-assembled monolayer (SAM) on top of the polished copper lines. The changed degradation mechanisms as observed with the in situ scanning electron microscopy (SEM) experiment and as predicted based on the numerical simulations are explained based on TEM images.
Microstructure and phase formation of Heusler thin film compounds
Authors: Thomas Jürgen , Schumann Joachim , Dománková Maria , Gemming Thomas
Published: February 2022

Heusler compounds are promising materials to be applied effectively as highly spin-polarized medium (or components) in spintronic devices. To prove their chances the microstructure, the phase formation, and the chemical homogeneity of sputtered thin films of Co2MnSi and Co2Cr0.6Fe0.4Al were studied by in-situ TEM observations as well as by analytical characterizations. The observed grain growth and phase formation in dependence on temperature agrees well with the results of measurements of the film resistivity. The chemical homogeneity varies and depends on the deposition process during thin film preparation, especially the incorporation of oxygen is an unwanted effect.
The local deformation behaviour of MMCs – an experimental study
Authors: Unterweger Klaus , Kolednik Otmar
Published: February 2022

The local deformation behaviour of powder metallurgy metal matrix composites (MMCs) with two different SiC particle sizes and aging conditions are investigated and compared to the behaviour of the un-reinforced matrix. In situ tensile loading experiments are carried out in a scanning electron microscope. Images taken at different deformation stages are analysed by a system for local deformation measurement. It is found that even the pure matrix material deforms inhomogeneously, showing a shear-band pattern which is independent of the loading stage. The MMCs with coarse reinforcements deform mainly due to shear bands which are induced by fractured particles. The MMCs with small particles exhibit a shear-band pattern which is controlled by the particle arrangement. The fracture of small particles does not induce far-reaching shear bands and, therefore, these materials have a higher strength and ductility.
The Haunting Past of Colonialism in Belgium the Death of Patrice Lumumba in Public Memory
Authors: Verbeeck Georgi
Published: February 2022

The remembrance of the death of Prime Minister Patrice Lumumba of the Republic of the Congo in Belgium is indicative of a fundamental transformation in the latter country’s public memory of its former role as a colonizing power in Central Africa. After decades of public amnesia and hesitation to confront the past, a new narrative is slowly gaining ground. A gradual transformation process is taking place at the intersection of historical research, political intervention, and popular culture. Changes in Belgium’s memory landscape not only reflect wider international trends but also express national and particular sensitivities.
Incorporating peer feedback in writing instruction: examining its effects on Chinese English-as-a-foreign-language (EFL) learners’ writing performance
Authors: Xu Zhiqing , Zhang Lawrence Jun , Parr Judy M.
Published: February 2022

Peer feedback has been widely employed in writing instruction in various contexts. However, studies into its effects on improving students’ writing performance, particularly its long-term effects, are under-represented. To fill the research gap, we adopted a pre-, post-, and delayed post-test quasi-experimental design to investigate the long-term effects of a peer feedback intervention. Two intact classes of EFL students from a Chinese university were recruited, with one class participating in peer feedback activities and the other class receiving collective feedback from their teacher for one semester. Their compositions for the pre-, post-, delayed post-tests were compared in terms of the overall text quality, content, organization, complexity, accuracy, and fluency (CAF). The results show that the experimental group participants made significant improvements in the overall text quality, content, organization, and accuracy in the post-test and they retained the improvements 12 weeks after the intervention. In addition, they outperformed their counterparts receiving collective feedback in the overall text quality and organization in the post- and delayed post-tests, and in accuracy only in the delayed post-test. Results suggest that peer feedback could help Chinese EFL learners make progress in writing.
Local controllability of hot electron and thermal effects enabled by chiral plasmonic nanostructures
Authors: Kang Bowen , Zhang Tingting , Yan Lei , Gou Chengxiang , Jiang Zihe , Ji Min , Chen Li , Zhang Zhenglong , Zheng Hairong , Xu Hongxing
Published: February 2022

The control of hot electron (HE) and thermal effects induced by plasmonic nanostructures has recently attracted considerable attention. When illuminated by light with different circular polarization states, the circular dichroism signal of molecules adsorbed by plasmonic chiral nanostructures can control HE and thermal effects. These effects have the potential to enhance reaction rates and to change selectivity patterns in photothermal catalysis. Here, we propose an aluminum L-shaped chiral nanostructure system in which HE and thermal effects can be controlled in different regions of the nanostructure by changing the chirality of the excitation light. A large difference of 12.75% in the HE effect but a virtually identical thermal effect can be achieved in different regions of the nanostructure by selecting the appropriate probed region, while a large thermal effect difference of 65.67% but a virtually identical HE effect can be achieved in one region of the nanostructure by changing the polarization state of the excitation light. In addition, the HE and thermal chiral selectivity effects of double L-shaped nanostructures are investigated as these structures can be more easily controlled during asymmetric chiral growth and crystallization. This work combined with plasmonic chirality is beneficial for quantifying HE and thermal effects in photochemical reactions and provides theoretical support for designing catalysts and optimizing plasmonic platforms. Additionally, the local controllability of HE and thermal effects plays an essential role in high-resolution photochemical reactions, especially in single-molecule photochemical reactions.