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On optimal control at the onset of a new viral outbreak

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Infectious Disease Modelling 2024年第4期9卷 995-1006页

作者： alexandra Smirnova Xiaojing Ye Department of Mathematics&Statistics Georgia State UniversityAtlantaUSA

We propose a versatile model with a flexible choice of control for an early-pandemic outbreak prevention when vaccine/drug is not yet *** that stage,control is often limited to non-medical interventions like social distancing and other behavioral *** the SIR optimal control problem,we show that the running cost of control satisfying mild,practically justified conditions generates an optimal strategy,u(t),t∈[0,T],that is sustainable up until some moment τ∈[0,T).However,for any t∈[τ,T],the function u(t)will decline as t approaches T,which may cause the number of newly infected people to ***,the window from 0 to τ is the time for public health officials to prepare alternative mitigation measures,such as vaccines,testing,antiviral medications,and *** addition to theoretical study,we develop a fast and stable computational method for solving the proposed optimal control *** efficiency of the new method is illustrated with numerical examples of optimal control trajectories for various cost functions and *** results provide a comprehensive demonstration of the effects of control on the epidemic spread and mitigation expenses,which can serve as invaluable references for public health officials.

关键词： Epidemiology Compartmental model Transmission dynamic Optimal control

Reconstruction of incidence reporting rate for SARS-CoV-2 Delta variant of COVID-19 pandemic in the US

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Infectious Disease Modelling 2024年第1期9卷 70-83页

作者： alexandra Smirnova Mona Baroonian Department of Mathematics&Statistics Georgia State UniversityAtlantaUSA

In recent years,advanced regularization techniques have emerged as a powerful tool aimed at stable estimation of infectious disease parameters that are crucial for future projections,prevention,and *** other system parameters,i.e.,incubation and recovery rates,the case reporting rate,Ψ,and the time-dependent effective reproduction number,R_(e)t,are directly influenced by a large number of factors making it impossible to pre-estimate these parameters in any meaningful *** this study,we propose a novel iteratively-regularized trust-region optimization algorithm,combined with SuSvIuIvRD compartmental model,for stable reconstruction ofΨand R_(e)t from reported epidemic data on vaccination percentages,incidence cases,and daily *** innovative regularization procedure exploits(and takes full advantage of)a unique structure of the Jacobian and Hessian approximation for the nonlinear observation *** proposed inversion method is thoroughly tested with synthetic and real SARS-CoV-2 Delta variant data for different regions in the United States of America from July 9,2021,to November 25,*** study shows that case reporting rate during the Delta wave of COVID-19 pandemic in the US is between 12%and 37%,with most states being in the range from 15%to 25%.This confirms earlier accounts on considerable under-reporting of COVID-19 cases due to the impact of”silent spreaders”and the limitations of testing.

关键词： Epidemiology Incidence reporting rate Compartmental model Transmission dynamic Regularization algorithm

Assistive Robotics for Upper Limb Physical Rehabilitation:A Systematic Review and Future Prospects

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Chinese Journal of Mechanical Engineering 2024年第4期37卷 50-73页

作者： Andrés Guatibonza Leonardo Solaque alexandra Velasco Lina Peñuela Department of Engineering Mechatronics EngineeringMilitar Nueva Granada UniversityBogotá1101111Colombia

Physical assistive robotics are oriented to support and improve functional capacities of *** physical rehabilitation,robots are indeed useful for functional recovery of affected ***,there are still open questions related to technological *** work presents a systematic review of upper limb rehabilitation robotics in order to analyze and establish technological challenges and future directions in this area.A bibliometric analysis was performed for the systematic literature *** from the last six years,conducted between August 2020 and May 2021,was *** methodology for the literature search and a bibliometric analysis of the metadata are *** a preliminary search resulted in 820 articles,a total of 66 articles were included.A concurrency network and bibliographic analysis were *** an analysis of occurrences,taxonomy,and rehabilitation robotics reported in the literature is *** review aims to provide to the scientific community an overview of the state of the art in assistive robotics for upper limb physical *** literature analysis allows access to a gap of unexplored options to define the technological prospects applied to upper limb physical rehabilitation robotics.

关键词： Upper limb Rehabilitation Assistive robotics Human-machine interaction Robotic systems Virtual reality Rehabilitation monitoring

Role of practice standardization in outcome optimization for CDH

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World Journal of Pediatric Surgery 2024年第2期7卷 110-118页

作者： alexandra Dimmer Robert Baird Pramod Puligandla Harvey E.Beardmore Division of Pediatric Surgery Department of Pediatric SurgeryMontreal Children's HospitalMontrealQuebecCanada Division of Pediatric General and Thoracic Surgery British Columbia Children's HospitalVancouverBritish ColumbiaCanada Harvey E.Beardmore Department of Pediatric Surgery McGill UniversityMontrealQuebecCanada

Standardization of care seeks to improve patient outcomes and healthcare delivery by reducing unwanted variations in care as well as promoting the efficient and effective use of healthcare *** are many types of standardization,with clinical practice guidelines(CPGs),based on a stringent assessment of evidence and expert consensus,being the hallmark of high-quality *** article outlines the history of CPGs,their benefits and shortcomings,with a specific focus on standardization efforts as it relates to congenital diaphragmatic hernia management.

关键词： congenital clinical shortcomings

Elevation transition of aquatic insects closely matches a thermal feature in the Yungas of Northwestern Argentina

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Journal of Mountain Science 2024年第2期21卷 433-448页

作者： alexandra BUITRAGO-GUACANAME Carlos MOLINERI Andrés LIRA-NORIEGA Daniel Andrés DOS SANTOS Neotropical Biodiversity Institute(CONICET-UNT) UNT-DomesHorco Molle S/N4107 TucumánArgentina CONACYT Research Fellow Network of Advanced Molecular StudiesInstitute of Ecology A.COld Road to Coatepec 351El HayaCP 91073XalapaVeracruzMexico Biostatistics Chair Faculty of Natural Sciences and IMLNational University of TucumánSan Miguel de TucumánMiguel Lillo 2054000 TucumánArgentina

Temperature is a key factor that shapes the distribution of *** knowledge about how species respond to temperature is relevant to devise strategies for addressing the impacts of climate *** insects are particularly vulnerable to climate change,yet there is still much to learn about their ecology and *** the Yungas ecoregion of Northwestern Argentina,cold-and warm-adapted species of the orders Ephemeroptera,Plecoptera,and Trichoptera(EPT)are segregated by *** modeled the ecological niche of South American EPT species in this region using available data and projected their potential distribution in geographic *** were grouped based on their ecogeographic similarity,and we analyzed their replacement pattern along elevation gradients,focusing on the ecotone where opposing thermal preferences *** this interface,we identified critical points where the combined incidence of cold and warm assemblages maximizes,indicating a significant transition *** found that the Montane Cloud Forest holds the interface,with a particularly greater suitability at its lower *** main axis of the interface runs in a N-S direction and falls between 14°C-16°C mean annual *** probability of a particular location within a basin being classified as part of the interface increases as Kira’s warmth index approaches a score around *** the interface is critical for defining the thermal limits of species distribution and designing biomonitoring *** in the location of thermal constants related to mountainous ecotones may cause vertical displacement of aquatic insects and vegetation *** have recognized significant temperature thresholds that serve as indicators of suitability for the *** global warming is anticipated to shift these indicators,we suggest using them to monitor the imprints of climate change on mountain ecosystems.

关键词： Austral Yungas Ecological Niche Model Ephemeroptera Kira’s warmth index Plecoptera Trichoptera

Development and characterization of 3D-printed electroconductive pHEMA-co-MAA NP-laden hydrogels for tissue engineering

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Bio-Design and Manufacturing 2024年第3期7卷 262-276页

作者： Sara De Nitto Aleksandra Serafin alexandra Karadimou Achim Schmalenberger John J.EMulvihill Maurice N.Collins DIBRIS Polytechnic Inter-School Section University of Genoa16126 GenoaItaly School of Engineering Bernal InstituteUniversity of LimerickLimerick V94 T9PXIreland School of Natural Sciences Department of Biological SciencesUniversity of LimerickLimerick V94 T9PXIreland Health Research Institute University of LimerickLimerick V94 T9PXIreland AMBER University of LimerickLimerick V94 T9PXIreland

Tissue engineering(TE)continues to be widely explored as a potential solution to meet critical clinical needs for diseased tissue replacement and tissue *** this study,we developed a poly(2-hydroxyethyl methacrylate-co-methacrylic acid)(pHEMA-co-MAA)based hydrogel loaded with newly synthesized conductive poly(3,4-ethylene-dioxythiophene)(PEDOT)and polypyrrole(PPy)nanoparticles(NPs),and subsequently processed these hydrogels into tissue engineered constructs via three-dimensional(3D)*** presence of the NPs was critical as they altered the rheological properties during ***,all samples exhibited suitable shear thinning properties,allowing for the development of an optimized processing window for 3D *** were 3D printed into pre-determined disk-shaped configurations of 2 and 10 mm in height and diameter,*** observed that the NPs disrupted the gel crosslinking efficiencies,leading to shorter degradation times and compressive mechanical properties ranging between 450 and 550 *** conductivity of the printed hydrogels increased along with the NP concentration to(5.10±0.37)×10^(−7)S/*** vitro studies with cortical astrocyte cell cultures demonstrated that exposure to the pHEMA-co-MAA NP hydrogels yielded high cellular viability and proliferation ***,hydrogel antimicrobial studies with staphylococcus epidermidis bacteria revealed that the developed hydrogels affected bacterial *** together,these materials show promise for various TE strategies.

关键词： Conductive nanoparticles Hydroxyethyl methacrylate(HEMA) Ultraviolet(UV)polymerization 3D printing

Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

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Science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng Si Dianming Sun Tomas Matulaitis David B.Cordes alexandra M.Z.Slawin Eli Zysman-Colman Organic Semiconductor Centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRISC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(ST), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. Such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF SP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

Phase transitions and degradation/oxidation mechanisms in lead-free CsSnI_(3)halide perovskites

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Clean Energy 2024年第3期8卷 109-115页

作者： alexandra Ivanova Margarita Golikova Lev Luchnikov Pavel Gostishchev Igor Shetinin Victor Voronov Danila Saranin Vladimir Khovaylo National University of Science and Technology MISIS(NUST MISIS) Leninsky av.4Moscow119049Russia Belgorod State University Pobedy st.85Belgorod308015Russia

Halide perovskites possess ultra-low thermal conductivity and show high potential for thermoelectric *** chemical properties and molecular structure of halide perovskite materials are not completely stable under ambient conditions,which hinders their use in thermoelectric *** in the properties of bulk halide perovskite thermoelectrics are accompanied by partial phase transitions and surface oxidation *** this paper,we conducted a comprehensive study of the transport and structural properties of CsSnI_(3),which were pristine by vacuum melting followed by spark plasma *** research results on the electrical transport of these materials revealed that exposure to an inert atmosphere does not deteriorate stability and the properties of the materials remain ***,prolonged exposure to air leads to a significant degradation of the electrical transport *** to thin-film samples,the shift to the double perovskite structure from the perovskite one is limited to a specific surface *** change significantly influences the electrical transport of the material while maintaining the essential properties of both perovskite types.

关键词： halide perovskites degradation oxidation transport properties surface

Imaging and endoscopic tools in pediatric inflammatory bowel disease: What’s new?

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World Journal of Clinical Pediatrics 2024年第1期13卷 7-13页

作者： alexandra S Hudson Ghassan T Wahbeh Hengqi Betty Zheng Department of Pediatrics University of WashingtonSeattleWA 98109United States

Pediatric inflammatory bowel disease(IBD)is a chronic inflammatory disorder,with increasing incidence and prevalence *** have been recent advances in imaging and endoscopic technology for disease diagnosis,treatment,and *** ultrasound,including transabdominal,transperineal,and endoscopic,has been emerging for the assessment of transmural bowel inflammation and disease complications(e.g.,fistula,abscess).Aside from surgery,IBD-related intestinal strictures now have endoscopic treatment options including through-the-scope balloon dilatation,injection,and needle knife stricturotomy and new evaluation tools such as endoscopic functional lumen imaging *** transnasal endoscopy may have a role in patients with upper gastrointestinal Crohn’s disease or those with IBD with new upper gastrointestinal *** to dysplasia screening in pediatric patients with longstanding colonic disease or primary sclerosing cholangitis hold promise with the addition of virtual chromoendoscopy and ongoing research in the field of artificial intelligence-assisted endoscopic *** intelligence and machine learning is a rapidly evolving field,with goals of further personalizing IBD diagnosis and treatment selection as well as *** review summarized these advancements,focusing on pediatric patients with IBD.

关键词： Intestinal ultrasound Endoscopy Inflammatory bowel disease Pediatrics Imaging