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A new method for precise optical measurements of the sub-micron height of levitation of droplet clusters

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Particuology 2024年第4期87卷 173-178页

作者： alexander A.Fedorets eduard e.Kolmakov Leonid A.Dombrovsky University of Tyumen 6 Volodarskogo StTyumen625003Russia engineering Faculty Ariel UniversityP0.B.3407000ArielIsrael Joint Institute for High Temperatures 17A Krasnokazarmennaya StMoscow111116Russia

Droplet clusters levitating over the locally heated water surface are considered a very promising phe-nomenon of microfluidics for the potential use of the droplets as unique microreactors for microbio-logical experiments.A new optical method is suggested for precise measurements of the sub-micron levitation height of single droplets.The method is based on the analysis of variable colors of the inter-ference halo around the droplet.For the first time,it is possible to measure the extremely low downward velocity of droplets,which grow due to steam condensation.This velocity was found to be 5-8 nm/s.The height of the levitation of various droplets just before their coalescence with a layer of water was also determined.Such measurements might be used for the verification of sophisticated models for the droplet levitation to be developed for a very thin layer of humid air under the droplet when the Knudsen effect should be taken into account.

关键词： Precise measurements Interferometric method Droplet cluster Levitation height

Scanning transmission electron microscopy and atom probe tomography analysis of non-stoichiometry long-period-stacking-ordered structures in Mg-Ni-Y/Sm alloys

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Journal of Magnesium and Alloys 2024年第3期12卷 954-965页

作者： Yimeng Chen Manuel Legrée Jean-Louis Bobet alexander Kvit CAMeCA Instruments Inc MadisonWI 53711USA ICMCB Universitéde BordeauxPessacCEDEX 33608France NIAC&Materials Science Department University of WisconsinMadisonWI 53706USA

The long-period-stacking-ordered(LPSO)structure affects the mechanical,corrosion and hydrolysis properties of Mg alloys.The current work employs high angle annular dark field-scanning transmission electron microscopy(HAADF-STeM)and atom probe tomography(APT)to investigate the structural and local chemical information of LPSO phases formed in Mg-Ni-Y/Sm ternary alloys after extended isothermal annealing.Depending on the alloying elements and their concentrations,Mg-Ni-Y/Sm develops a two-phase LPSO+α-Mg structure in which the LPSO phase contains defects,hybrid LPSO structure,and Mg insertions.HAADF-STeM and APT indicate non-stoichiometric LPSO with incomplete Ni_(6)(Y/Sm)_(8) clusters.In addition,the APT quantitatively determines the local composition of LPSO and confirms the presence of Ni within the Mg bonding layers.These results provide insight into a better understanding of the structure and hydrolysis properties of LPSO-Mg alloys.

关键词： Magnesium alloys Long-range ordering Atom probe tomography(APT) STeM HAADF Hydrolysis properties.

A Converse Theorem for Split SO_(2l) over Finite Fields

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Acta Mathematica Sinica,english Series 2024年第3期40卷 731-771页

作者： alexander HAZeLTINe Bai Ying LIU Department of Mathematics Purdue University150 N.University St.West LafayetteIN 47907USA E-mail:ahazelti@purdue.edu liu2053@purdue.edu

We prove a converse theorem for split even special orthogonal groups over finite fields.This is the only case left on converse theorems of classical groups and the difficulty is the existence of the outer automorphism... 详细信息

关键词： Converse theorems generic cuspidal representations even special orthogonal groups

Unveiling the atomic-scale transition between light harvesting and photoprotective states in plant photosynthesis

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Science China Chemistry 2024年第5期67卷 1375-1377页

作者： alexander V.Ruban School of Biological and Behavioural Sciences Queen Mary University of LondonLondon E14NSUK

Non-photochemical chlorophyll fluorescence quenching(NPQ) stands as a cornerstone in the realm of photosynthesis research, attracting generations of dedicated scientists in their quest to unravel its mysteries. This mechanism, crucial for safeguarding photosynthesis, plays a pivotal role in regulating light harvesting, particularly in oxygenic photosynthesis where the oxygen-evolving photosystem II (PSII)is susceptible to photodamage [1].

关键词： harvesting protective attracting

Transcriptional reprogramming during human osteoclast differentiation identifies regulators of osteoclast activity

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Bone Research 2024年第1期12卷 180-198页

作者： Morten S.Hansen Kaja Madsen Maria Price Kent Søe Yasunori Omata Mario M.Zaiss Caroline M.Gorvin Morten Frost alexander Rauch Molecular endocrinology Laboratory(KMeB) Department of EndocrinologyOdense University HospitalDK-5000 Odense CDenmark Department of Clinical Research Faculty of Health SciencesUniversity of Southern DenmarkDK-5000 Odense CDenmark Clinical Cell Biology Pathology Research UnitDepartment of Clinical ResearchUniversity of Southern DenmarkDK-5000 Odense CDenmark Institute of Metabolism and Systems Research(IMSR)and Centre for Diabetes Endocrinology and Metabolism(CEDAM)University of BirminghamBirmingham B152TTUK Centre for Membrane Proteins and Receptors(COMPARe) Universities of Birmingham and NottinghamBirmingham B152TTUK Department of Molecular Medicine University of Southern DenmarkDK-5000 Odense CDenmark Department of Orthopedic Surgery Faculty of MedicineThe University of TokyoTokyo 113-8655Japan Department of Internal Medicine 3 Rheumatology and ImmunologyFriedrich-Alexander-University Erlangen-Nürnberg(FAU)and Universitätsklinikum ErlangenD-91054 ErlangenGermany Deutsches Zentrum Immuntherapie(DZI) Friedrich-Alexander-University Erlangen-Nürnberg and Universitätsklinikum ErlangenD-91054 ErlangenGermany Steno Diabetes Center Odense Odense University HospitalDK-5000 Odense CDenmark

enhanced osteoclastogenesis and osteoclast activity contribute to the development of osteoporosis,which is characterized by increased bone resorption and inadequate bone formation.As novel antiosteoporotic therapeutics are needed,understanding the genetic regulation of human osteoclastogenesis could help identify potential treatment targets.This study aimed to provide an overview of transcriptional reprogramming during human osteoclast differentiation.Osteoclasts were differentiated from CD14+monocytes from eight female donors.RNA sequencing during differentiation revealed 8980 differentially expressed genes grouped into eight temporal patterns conserved across donors.These patterns revealed distinct molecular functions associated with postmenopausal osteoporosis susceptibility genes based on RNA from iliac crest biopsies and bone mineral density SNPs.Network analyses revealed mutual dependencies between temporal expression patterns and provided insight into subtype-specific transcriptional networks.The donor-specific expression patterns revealed genes at the monocyte stage,such as filamin B(FLNB)and oxidized low-density lipoprotein receptor 1(OLR1,encoding LOX-1),that are predictive of the resorptive activity of mature osteoclasts.The expression of differentially expressed G-protein coupled receptors was strong during osteoclast differentiation,and these receptors are associated with bone mineral density SNPs,suggesting that they play a pivotal role in osteoclast differentiation and activity.The regulatory effects of three differentially expressed G-protein coupled receptors were exemplified by in vitro pharmacological modulation of complement 5 A receptor 1(C5AR1),somatostatin receptor 2(SSTR2),and free fatty acid receptor 4(FFAR4/GPR120).Activating C5AR1 enhanced osteoclast formation,while activating SSTR2 decreased the resorptive activity of mature osteoclasts,and activating FFAR4 decreased both the number and resorptive activity of mature osteoclasts.In conclusion,we report the occurrence of transcriptional

关键词： osteoclast programming identif

New perspectives on biology,disease progression,and therapy response of head and neck cancer gained from single cell RNA sequencing and spatial transcriptomics

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Oncology Research 2024年第1期32卷 1-17页

作者： GeRWIN HeLLeR THORSTeN FUeReDeR alexander MICHAeL GRANDITS ROTRAUD WIeSeR Division of Oncology Department of Medicine IMedical University of ViennaVienna1090Austria Ludwig Boltzmann Institute for Hematology and Oncology Medical University of ViennaVienna1090Austria

Head and neck squamous cell carcinoma(HNSCC)is one of the most frequent cancers worldwide.The main risk factors are consumption of tobacco products and alcohol,as well as infection with human papilloma virus.Approved therapeutic options comprise surgery,radiation,chemotherapy,targeted therapy through epidermal growth factor receptor inhibition,and immunotherapy,but outcome has remained unsatisfactory due to recurrence rates of~50%and the frequent occurrence of second primaries.The availability of the human genome sequence at the beginning of the millennium heralded the omics era,in which rapid technological progress has advanced our knowledge of the molecular biology of malignant diseases,including HNSCC,at an unprecedented pace.Initially,microarray-based methods,followed by approaches based on next-generation sequencing,were applied to study the genetics,epigenetics,and gene expression patterns of bulk tumors.More recently,the advent of single-cell RNA sequencing(scRNAseq)and spatial transcriptomics methods has facilitated the investigation of the heterogeneity between and within different cell populations in the tumor microenvironment(e.g.,cancer cells,fibroblasts,immune cells,endothelial cells),led to the discovery of novel cell types,and advanced the discovery of cell-cell communication within tumors.This review provides an overview of scRNAseq,spatial transcriptomics,and the associated bioinformatics methods,and summarizes how their application has promoted our understanding of the emergence,composition,progression,and therapy responsiveness of,and intercellular signaling within,HNSCC.

关键词： Head and neck squamous cell carcinoma Tumor microenvironment Immunotherapy Gene expression Omics

Pelvic fractures in blunt trauma patients:A comparative study

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World Journal of Orthopedics 2024年第5期15卷 418-434页

作者： alexander A Fokin Joanna Wycech Knight Madison e Tharp Kyler C Brinton Phoebe K Gallagher Justin Fengyuan Xie Russell D Weisz Ivan Puente Trauma and Critical Care Services Delray Medical CenterDelray BeachFL 33484United States Charles e Schmidt College of Medicine Department of SurgeryFlorida Atlantic UniversityBoca RatonFL 33431United States Trauma and Critical Care Services Broward Health Medical CenterFort LauderdaleFL 33316United States Charles e Schmidt College of Medicine Florida Atlantic UniversityBoca RatonFL 33431United States Herbert Wertheim College of Medicine Department of SurgeryFlorida International UniversityMiamiFL 33199United States

BACKGROUND Pelvic fractures(PF)with concomitant injuries are on the rise due to an increase of high-energy trauma.Increase of the elderly population with age related comorbidities further complicates the management.Abdominal organ injuries are kindred with PF due to the proximity to pelvic bones.Presence of contrast blush(CB)on computed tomography in patients with PF is considered a sign of active bleeding,however,its clinical significance and association with outcomes is debatable.AIM To analyze polytrauma patients with PF with a focus on the geriatric population,co-injuries and the value of contrast blush.MeTHODS This retrospective cohort study included 558 patients with PF admitted to level 1 trauma center(01/2017-01/2023).Analyzed variables included:Age,sex,mechanism of injury(MOI),injury severity score(ISS),Glasgow coma scale(GCS),abbreviated injury scale(AIS),co-injuries,transfusion requirements,pelvic angiography,embolization,laparotomy,orthopedic pelvic surgery,intensive care unit and hospital lengths of stay,discharge disposition and mortality.The study compared geriatric and non-geriatric patients,patients with and without CB and abdominal co-injuries.Propensity score matching was implemented in comparison groups.ReSULTS PF comprised 4%of all trauma admissions.89 patients had CB.286(52%)patients had concomitant injuries including 93(17%)patients with abdominal co-injuries.Geriatric patients compared to non-geriatric had more falls as MOI,lower ISS and AIS pelvis,higher GCS,less abdominal co-injuries,similar CB and angio-embolization rates,less orthopedic pelvic surgeries,shorter lengths of stay and higher mortality.After propensity matching,orthopedic pelvic surgery rates remained lower(8%vs 19%,Pength of stay shorter,and mortality higher(13%vs 4%,Periatric patients.Out of 89 patients with CB,45(51%)were embolized.After propensity matching,patients with CB compared to without CB had more pelvic angiography(71%vs 12%,Per embolization rates(64%vs 22%,P=0.02)and com

关键词： Pelvic fractures Geriatric trauma patients Abdominal co-injuries Contrast blush Contrast extravasation Angioembolization Polytrauma patients Surgical interventions Blunt trauma external and internal fixation for pelvic stabilization

Review on the plastic instability of medium -Mn steels for identifying the formation mechanisms of Lüders and Portevin -Le Chatelier bands

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1285-1297页

作者： Bin Hu Han Sui Qinghua Wen Zheng Wang alexander Gramlich Haiwen Luo School of Metallurgical and ecological engineering University of Science and Technology BeijingBeijing 100083China Steel Institute RWTH Aachen UniversityIntzestraße 152072 AachenGermany

Plastic instability,including both the discontinuous yielding and stress serrations,has been frequently observed during the tensile deformation of medium-Mn steels(MMnS)and has been intensively studied in recent years.Unfortunately,research results are controversial,and no consensus has been achieved regarding the topic.Here,we first summarize all the possible factors that affect the yielding and flow stress serrations in MMnS,including the morphology and stability of austenite,the feature of the phase interface,and the deformation parameters.Then,we propose a universal mechanism to explain the conflicting experimental results.We conclude that the discontinuous yielding can be attributed to the lack of mobile dislocation before deformation and the rapid dislocation multiplication at the beginning of plastic deformation.Meanwhile,the results show that the stress serrations are formed due to the pinning and depinning between dislocations and interstitial atoms in austenite.Strain-induced martensitic transformation,influenced by the mechanical stability of austenite grain and deformation parameters,should not be the intrinsic cause of plastic instability.However,it can intensify or weaken the discontinuous yielding and the stress serrations by affecting the mobility and density of dislocations,as well as the interaction between the interstitial atoms and dislocations in austenite grains.

关键词： medium manganese steel discontinuous yielding stress serrations retained austenite dislocations

Impact of doping profiles on the formation of laser-active centers in bismuth-doped GeO_(2)–SiO_(2)glass fibers

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Photonics Research 2024年第2期12卷 260-270页

作者： SeRGeY ALYSHeV alexander VAKHRUSHeV ALeKSANDR KHeGAI eLeNA FIRSTOVA KONSTANTIN RIUMKIN MIKHAIL MeLKUMOV LYUDMILA ISKHAKOVA ANDReY UMNIKOV SeRGeI FIRSTOV Prokhorov General Physics Institute of the Russian Academy of Sciences Dianov Fiber Optics Research Center119333 MoscowRussia Devyatykh Institute of Chemistry of High-Purity Substances of the Russian Academy of Sciences 603951 Nizhny NovgorodRussia

Multi-wavelength-band transmission technology based on the exploitation of the extended spectral region is considered as a potential approach to increase the transmission capacity in the deployed fiber-optic communication infrastructure.The development of optical amplifiers operating in the O-,e-,S-,and U-telecom bands is an extremely important challenge for the successful implementation of this technology.Bismuth-doped fibers are of increasing interest as gain materials,which can be used to provide broadband amplification in the mentioned telecom bands.This is due to the ability of Bi ions incorporated into glass network to form bismuth active centers(BACs)with specific optical properties,which are primarily determined by the glass modifiers.In this work,the impact of the doping profiles of both Ge atoms as glass modifiers and Bi ions on the BACs formation is studied using a series of bismuth-doped fibers fabricated by the modified chemical vapor deposition(MCVD)technique.The Bi-to-BACs conversion efficiency in various spatial regions of the studied samples is presented.It is turned out that for high-Bi concentration regions,the conversion efficiency is very low(less than 10%).In addition,the relationship of the conversion efficiency to the distribution of Bi ions and/or Ge atoms is discussed.Finally,a continuous-wave laser at 1.46μm with a record slope efficiency of 80%is demonstrated using a Bi-doped fiber with confined doping profile,where the Bi-to-BACs conversion efficiency is 35%.This paper provides new information which might help to facilitate understanding of the features of Bi-doped fibers and their potentially achievable characteristics.

关键词： fiber fibers bismuth