检索结果-南通市图书馆

NHC-catalysed[3+2]-asymmetric annulation between pyrazolin-4,5-diones and enals:synthesis of novel spirocyclic pyrazolone γ-butyrolactones and computational study of mechanism and stereoselectivity

在线全文

学校读者我要写书评

暂无评论

Organic Chemistry Frontiers 2022年第2期9卷 420-427页

作者： Marta Gil-Ordonez Alicia Maestro Pablo Ortega Pablo G.Jambrina Jose M.Andres GIR-SintACat-Instituto Universitario CINQUIMA y departamento de Química Orgánica Facultad de CienciasUniversidad de ValladolidPaseo Belén 747011 ValladolidSpain departamento de Química Física University of Salamanca37008 SalamancaSpain

Chiral pyrazolones with a spirocyclic centre at the C4-position are widely found in a large family of medically relevant *** recent years,organocatalysis,particularly that performed with quiral N-heterocyclic carbenes(NHCs),has allowed the enantioselective synthesis of these spirocyclic compounds despite its inherent *** this work,we describe the fully diastereo-and highly enantioselective synthesis of novel spirocyclic pyrazolone γ-butyrolactones via NHC-catalysed[3+2]annulation reaction of enals and 1H-pyrazol-4,*** understand the catalytic mechanism and origin of stereoselectivity,electronic structure calculations were carried *** considering various pathways,we concluded that the stereoselectivity-determining step is the formation of the lactone that proceeds after addition of the NHC derived homoenolate to the electrophilic carbonyl group of pyrazolin-4,*** calculations predict that the free energy barrier is lower for the(RS)product,which is also the main product experimentally obtained.

关键词： synthesis spiro mechanism

Single droplet drying of detergents:Experimentation and modelling

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2021年第5期19卷 35-47页

作者： Borja Hernandez Rosa Mondragon Mark A.Pintoa Leonor Hernandez J.Enrique Julia Juan Carlos Jarque Sergio Chiva Mariano Martin Newcastle Innovation Centre Procter&Gamble R&DNewcastle upon TyneUK departamento de Ingenieria Quimica y Textil.universidad de salamanca SalamancaSpain departamento de Ingenieria Mecanica y Construccion Universitat Jaume ICastellon de la PlanaSpain Instituto de Tecnologia Ceramica Universitat Jaume ICastellon de la PlanaSpain

This study evaluates the single droplet drying(SDD)of *** data are used to validate a theoretical multistage *** experiments are carried out in an acoustic levitator analysing six different detergent formulations at 393 *** work is completed by developing a model based on conservation *** model is composed of the three stages observed in the drying *** the first stage,an external surface drying stage occurs until the surface is saturated and the crust is *** the next stage,the drying rate is governed by diffusion through the *** the same time,the particle heats up until boiling conditions are achieved in the core of the *** this point,the third stage *** the final stage,the droplet core is in boiling conditions which are governed by the pressure drop through the crust and the concentration of *** model has been evaluated for the different formulations being flexible to predict the drying of different mixtures with good accuracy.

关键词： Drying Single droplet Acoustic levitator detergents

Coping with drought?Effects of extended drought conditions on soil invertebrate prey and diet selection by a fossorial amphisbaenian reptile

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Current Zoology 2023年第4期69卷 367-376页

作者： José Martín Jesús Ortega Roberto García-Roa Gonzalo Rodríguez-Ruiz Ana Pérez-Cembranos Valentín Pérez-Mellado departamento de Ecología Evolutiva Museo Nacional de Ciencias NaturalesCSICMadridSpain Institute of Evolutionary Biology CSIC-Universitat Pompeu FabraBarcelonaSpain Ethology Lab Cavanilles Institute of Biodiversity and Evolutionary BiologyUniversity of ValenciaValenciaSpain departamento de Biología Animal Universidad de SalamancaSalamancaSpain

Arid climates are characterized by a summer drought period to which animals seem ***,in some years,the drought can extend for unusually longer *** the effects of these current extreme weather events on biodiversity can help to understand the effects of climate change,as models predict an increase in drought ***,we examined the effects of“unusual”extended drought on soil invertebrate prey availability and on diet composition(based on fecal contents)and diet selection of a fossorial amphisbaenian,the checkerboard worm lizard Trogonophis *** data show interannual variations in summer drought *** abundance and diversity of soil invertebrates in spring were high,and similar to those found in a“normal”early autumn,after some rain had ended with the summer *** contrast,in years with“unusual”extended drought,abundance,and diversity of soil invertebrates in early autumn were very ***,there were seasonal changes in amphisbaenians’diet;in autumn with drought,prey diversity,and niche breadth decreased with respect to spring and autumns after some rain had *** did not eat prey at random in any season,but made some changes in prey selection that may result from drought-related restrictions in prey ***,in spite that amphisbaenians showed some feeding flexibility,their body condition was lower in autumn than in spring,and much lower in autumn with *** extended drought became the norm in the future,amphisbaenians might suffer important negative effects for their health state.

关键词： amphisbaenians drought feeding ecology soil invertebrates Trogonophis wiegmanni weather conditions

Semileptonic bc to cc and bb to bc baryon decays and heavy quark spin symmetry

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2010年第9期34卷 1364-1367页

作者： J.Nieves J.M.Flynn E.Hernández Instituto de Física corpuscular (IFIC) Centro Mixto Universidad de Valencia-CSICInstitutos de Investigación de Paterna School of Physics and Astronomy University of Southampton departamento de Física Fundamental e IUFFyM Universidad de Salamanca

We study the semileptonic decays of the lowest-lying bc baryons to the lowest-lying cc baryons （Ξ （＊） bc → Ξ （＊） cc and Ω （＊） bc → Ω （＊） cc ）,in the limit m b,m c Λ QCD and close to the zero recoil *** separate heavy quark spin symmetries make it possible to describe all these decays using a single form *** also show how these constraints can be used to test the validity of different quark model *** to bc baryon decays are also discussed.

关键词： heavy quark spin symmetry semileptonic decays constituent quark modelsIf

A brief history of the Rheic Ocean

在线全文

学校读者我要写书评

暂无评论

Geoscience Frontiers 2012年第2期3卷 125-135页

作者： R.Damian Nance Gabriel Gutirrez-Alonso J.Duncan Keppie Ulf Linnemann J.Brendan Murphy Cecilio Quesada Rob A.Strachan Nigel H.Woodcock department of geological Sciences 316 Clippinger Laboratories Ohio University departamento de geología universidad de salamanca 33708 Salamanca departamento de geología Regional Instituto de geología Universidad Nacional Autónoma de Mxico Senckenberg Naturhistorische Sammlungen Dresden Museum fur Mineralogie und geologie Konigsbrucker Landstra βe 159D-01109 DresdenGermany department of Earth Sciences St.Francis Xavier University Instituto Geolóogico y Minero de Espaa Ríos Rosas 2328003 MadridSpain School of Earth & Environmental Sciences University of Portsmouth department of Earth Sciences University of Cambridge Downing StreetCambridge CB2 3EQUK

The Rheic Ocean was one of the most important oceans of the Paleozoic Era. It lay between Laurentia and Gondwana from the Early Ordovician and closed to produce the vast Ouachita- Alleghanian-Variscan orogen during the assembly of Pangea. Rifting began in the Cambrian as a continua- tion of Neoproterozoic orogenic activity and the ocean opened in the Early Ordovician with the separation of several Neoproterozoic arc terranes from the continental margin of northern Gondwana along the line of a former suture. The rapid rate of ocean opening suggests it was driven by slab pull in the outboard Iapetus Ocean. The ocean reached its greatest width with the closure of Iapetus and the accretion of the peri- Gondwanan arc terranes to Laurentia in the Silurian. Ocean closure began in the devonian and continued through the Mississippian as Gondwana sutured to Laurussia to form Pangea. The ocean consequently plays a dominant role in the Appalachian-Ouachita orogeny of North America, in the basement geology of southern Europe, and in the Paleozoic sedimentary, structural and tectonothermal record from Middle America to the Middle East. Its closure brought the Paleozoic Era to an end.

关键词： Rheic Ocean Variscan-Alleghanian-Ouachita orogen Pangea North America Europe

All-optical nonlinear chiral ultrafast magnetization dynamics driven by circularly polarized magnetic fields

在线全文

学校读者我要写书评

暂无评论

High Power Laser Science and Engineering 2023年第6期11卷 154-161页

作者： Luis Sánchez-Tejerina Rodrigo Martín-Hernández Rocío Yanes Luis Plaja Luis López-Díaz Carlos Hernández-García Grupo de Investigación en Aplicaciones del Láser y Fotónica Departamento de Física AplicadaUniversidad de SalamancaSalamancaSpain Present address:departamento de Electricidad y Electrónica Universidad de ValladolidValladolidSpain departamento de Física Aplicada Universidad de SalamancaSalamancaSpain Unidad de Excelencia en Luz y Materia Estructuradas(LUMES) Universidad de SalamancaSalamancaSpain

Ultrafast laser pulses provide unique tools to manipulate magnetization dynamics at femtosecond timescales,where the interaction of the electric field usually dominates over the magnetic *** proposals using structured laser beams have demonstrated the possibility to produce regions where intense oscillating magnetic fields are isolated from the electric *** these conditions,we show that technologically feasible tesla-scale circularly polarized high-frequency magnetic fields induce purely precessional nonlinear magnetization *** fundamental result not only opens an avenue in the study of laser-induced ultrafast magnetization dynamics,but also sustains technological implications as a route to promote all-optical non-thermal magnetization dynamics both at shorter timescales-towards the subfemtosecond regime-and at THz frequencies.

关键词： chiral behavior nonlinear dynamics ultrafast dynamics

C3G contributes to platelet activation and aggregation by regulating major signaling pathways

在线全文

学校读者我要写书评

暂无评论

Signal Transduction and Targeted Therapy 2020年第1期5卷 2103-2117页

作者： Sara Gutiérrez-Herrero Cristina Fernández-Infante Luis Hernández-Cano Sara Ortiz-Rivero Carlos Guijas Víctor Martín-Granado JoséRamón González-Porras Jesús Balsinde Almudena Porras Carmen Guerrero Instituto de Biología Molecular y Celular del Cáncer(IMBCC) University of Salamanca-CSICSalamancaSpain Instituto de Investigación Biomédica de salamanca(IBSAL) SalamancaSpain Instituto de Biología y Genética Molecular(IBGM) Consejo Superior de Investigaciones Científicas(CSIC)University of ValladolidValladolidSpain Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas(CIBERdeM) MadridSpain departamento de Hematologiá Hospital Universitario de Salamanca(HUS)SalamancaSpain departamento de Bioquímica y Biología Molecular Facultad de FarmaciaComplutense University of Madrid.Instituto de Investigación Sanitaria del Hospital Clínico San Carlos(IdISSC)MadridSpain departamento de Medicina University of SalamancaSalamancaSpain

C3G is a GEF(guanine nucleotide exchange factor)for Rap GTPases,among which the isoform Rap1b is an essential protein in platelet *** transgenic mouse models with platelet-specific overexpression of C3G or mutant C3GΔCat,we have unveiled a new function of C3G in regulating the hemostatic function of platelets through its participation in the thrombin-PKCRap1b pathway.C3G also plays important roles in angiogenesis,tumor growth,and metastasis through its regulation of the platelet *** addition,C3G contributes to megakaryopoiesis and ***,we used a platelet-specific C3G-KO mouse model to further support the role of C3G in hemostasis.C3G-KO platelets showed a significant delay in platelet activation and aggregation as a consequence of the defective activation of Rap1,which resulted in decreased thrombus formation in ***,we explored the contribution of C3G-Rap1b to platelet signaling pathways triggered by thrombin,PMA or ADP,in the referenced transgenic mouse model,through the use of a battery of specific *** found that platelet C3G is phosphorylated at Tyr504 by a mechanism involving *** phosphorylation was shown to be positively regulated by ERKs through their inhibition of the tyrosine phosphatase ***,C3G participates in the ADP-P2Y12-PI3K-Rap1b pathway and is a mediator of thrombin-TXA2 ***,it inhibits the synthesis of TXA2 through cPLA2 *** together,our data reveal the critical role of C3G in the main pathways leading to platelet activation and aggregation through the regulation of Rap1b.

关键词： C3G platelet activation

ΛΛN−ΞNN S wave resonance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第10期44卷 124-128页

作者： H.Garcilazo A.Valcarce Escuela Superior de Física y Matemáticas Instituto Politécnico NacionalEdificio 907738 México D.F.Mexico departamento de Física Fundamental Universidad de Salamanca37008 SalamancaSpain

We use an existing model of theΛΛN−ΞNN three-body system based on two-body separable interactions to study the(I,JP)=(1/2,1/2+)three-body *** theΛΛ,ΞN,andΛΛ−ΞN amplitudes,we have constructed separable potentials based on the most recent results of the HAL QCD *** are characterized by the existence of a resonance just below or above theΞN threshold in the H-dibaryon channel,(i,jp)=(0,0+).A three-body resonance appears 2.3 MeV above theΞd *** show that if theΛΛ−ΞN H-dibaryon channel is not considered,theΛΛN−ΞNN S wave resonance ***,the possible existence of aΛΛN−ΞNN resonance would be sensitive to theΛΛ−ΞN *** existence or nonexistence of this resonance could be evidenced by measuring,for example,theΞd cross section.

关键词： baryon-baryon interactions Faddeev equations

Scalable and low-cost fabrication of flexible WS_(2) photodetectors on polycarbonate

在线全文

学校读者我要写书评

暂无评论

npj Flexible Electronics 2022年第1期6卷 226-234页

作者： Jorge Quereda Sruthi Kuriakose Carmen Munuera Federico J.Mompean Abdullah M.Al-Enizi Ayman Nafady Enrique Diez Riccardo Frisenda Andres Castellanos-Gomez GISC Departamento de Física de MaterialesUniversidad Complutense de MadridMadridSpain Materials Science Factory Instituto de Ciencia de Materiales de Madrid(ICMMCSIC)28049 MadridSpain department of Chemistry College of ScienceKing Saud UniversityRiyadh 11451Saudi Arabia Nanotechnology Group USAL–NanolabUniversidad de Salamanca37008 SalamancaSpain

We present a low-cost and easy-to-implement technique to fabricate large-area WS_(2) photodetector devices onto transparent and flexible polycarbonate *** method relies on the deposition of large-area(in the cm scale)thin films(~30 nm thick)of WS_(2) by a recently introduced abrasion-induced *** electrical contacts are then deposited by thermal evaporation through a shadow *** photodetectors present well-balanced performances with an good trade-off between responsivity(up to 144 mA/W at a source-drain voltage of 10 V and illumination power of 1μW)and response time(down to~70µs)and a detectivity value of 10^(8) *** found that the devices perform very reversibly upon several illumination and straining cycles and we found a moderate device-to-device variation.

关键词： drain illumination cost