检索结果-南通市图书馆

维普期刊数据库

Synthesis of Unprotectedα-Tertiary Amines and 1,2-Amino Alcohols from Vinyl Azides by Light Induced Denitrogenative Alkylarylation/Dialkylation

在线全文

学校读者我要写书评

暂无评论

CCS Chemistry 2024年第4期6卷 1060-1070页

作者： Sifan Li Hai-wu Du paul w.Davies wei Shu Department of Chemistry Shenzhen Grubbs InstituteSouthern University of Science and TechnologyShenzhen 518055Guangdong school of Chemistry University of BirminghamEdgbastonBirmingham B152TT

Sterically congestedα-tertiary primary amines are ubiquitous substructures in pharmaceutical and agrochemical agents yet are challenging to ***,straightforward photoredox-catalyzed access to structurally diverseα,α,α-trisubstituted primary amines from denitrogenative alkylarylation or dialkylation of vinyl azides with N-hydroxyphthalimide(NHPI)esters and cyanoarenes or aryl aldehydes has been *** use of vinyl azide as a precursor to a primary aminewas enabled by the dual role of the Hantzsch ester to form an electron donor-acceptor complex and serve as a sacrificial *** strategy provides a modular synthesis ofα-tertiary primary amines,including unprotected 1,2-amino alcohols,from simple materials with excellent functional group *** synthetic applicability of this method was demonstrated by streamlined access to 2,2-disubstituted *** investigations support two parallel reductive photocatalytic cycles allowing for the denitrogenative alkylarylation or dialkylation of vinyl azides via decarboxylative radical addition followed by heteroradical cross-coupling betweenα-amino radicals and aryl anion radicals or ketyl anion radicals.

关键词： photocatalysis α-tertiary primary amines 1 2-amino alcohols vinyl azide electron donor-acceptor complex

Towards a sustainable geoliner construction in landflls by potential blending of fly ash with kaolin clay alternative:a review with an insight to Indian scenario

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

waste Disposal and Sustainable Energy 2024年第2期6卷 243-258页

作者： Kshitij Kumar Biswajit paul Department of Environmental Science and Engineering Indian Institute of Technology(Indian School of Mines)Dhanbad 826004JharkhandIndia

Electricity generated through coal-based Thermal Power Plants(TPPs)has played a pivotal role in shaping modern civiliza-tion,revolutionizing industries,and improving the quality of life for billions of people *** TPPs contribute to about 37%-40%of the global energy *** production,in turn,has a direct impact on the economy of any *** from this boon to humankind,these TPPs combusting coal as their primary fuel also have specific environmen-tal impacts,the major ones being water,air,and soil pollution due to unscientific disposal of high-quantity fly ash produced *** we can put this ash to good use,it may assist us in mitigating the pollution caused by *** there are many conventional uses of fly ash,such as a pozzolanic material in the cement industry,more pathways need to be discovered to balance the high generation quantities with ***,a detailed description of its use in potential geoliner applications is presented in this article.A geoliner or a landfill liner acts as a virtually impenetrable layer to mitigate the leachate penetration into the underneath subsoil and groundwater,thus preventing *** are presently some studies that support the use of only fly ash in such ***,the properties of the geoliners using it are not so good to significantly mitigate environmental degradation owing to its high permeability and low densification *** bentonite conventionally used has limited deposits and is mined intensively for its use as a natural *** depos-its must also be conserved,and an alternative material that may serve similar application benefits,like bentonite,must be *** desired aim can be fulfilled if we blend this combustion residue with other suitable materials(such as kaolinite clay)with low ***,the article focuses on the possibilities of blending fly ash with different clays for geoliner construction to improve the in

关键词： Fly ash-Geoliner Environmental management Composite liner systems Bentonite Kaolin clay

Efficient scar-free knock-ins of several kilobases in plants by engineered CRISPR-Cas endonucleases

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2024年第5期17卷 824-837页

作者： Tom schreiber Anja Prange Petra schafer Thomas Iwen Ramona Grutzner Sylvestre Marillonnet Aurelie Lepage Marie Javelle wyatt paul Alain Tissier Department of Cell and Metabolic Biology Leibniz Institute of Plant BiochemistryWeinberg 306120 Halle(Saale)Germany Limagrain Centre de RechercheRoute d’EnnezatCS 9012663720 ChappesFrance

In plants and mammals,non-homologous end-joining is the dominant pathway to repair DNA doublestrand breaks,making it challenging to generate knock-in *** this study,we identified two groups of exonucleases from the herpes virus and the bacteriophage T7 families that conferred an up to 38-fold increase in homology-directed repair frequencies when fused to Cas9/Cas12a in a tobacco mosaic virus-based transient assay in Nicotiana *** achieved precise and scar-free insertion of several kilobases of DNA both in transient and stable transformation *** Arabidopsis thaliana,fusion of Cas9 to a herpes virus family exonuclease led to 10-fold higher frequencies of knock-ins in the first generation of *** addition,we demonstrated stable and heritable knock-ins in wheat in 1%of the primary *** together,our results open perspectives for the routine production of heritable knock-in and gene replacement events in plants.

关键词： homology-directed repair knockin gene replacement CRISPR-Cas 50 exonuclease plants

Strain-dependent alpha-synuclein spreading in Parkinson's disease and multiple system atrophy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2024年第12期19卷 2581-2582页

作者： Shuyu Zhang paul Lingor Department of Neurology School of MedicineUniversity Hospital rechts der IsarTechnical University of MunichMunichGermany Department of Neurology University Medical Center GöttingenGöttingenGermany Center for Biostructural Imaging of Neurodegeneration University Medical Center GöttingenGöttingenGermany

Parkinson's disease(PD) and atypical Parkinsonian syndromes,such as multiple system atrophy(MSA) and Dementia with Lewy bodies,are neurodegenerative movement disorders characterized by the accumulation of alphasynuclein(a-syn) *** a-syn aggregates propagate throughout the brain in a prion-like manner,where pathological a-syn recruits endogenous a-syn to form insoluble *** forms representing intermediates on the way to insoluble aggregates result in the most pronounced neurotoxic effects.

关键词： atrophy endogenous atypical

维普期刊数据库

Tensor perturbations from bounce inflation scenario in f(Q)gravity

在线全文

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 78-92页

作者： Kun Hu Tanmoy paul Taotao Qiu Institute of Astrophysics Central China Normal UniversityWuhan 430079China school of Physics Huazhong University of Science and TechnologyWuhan 430074China National Institute of Technology Jamshedpur Department of PhysicsJamshedpur 831014India

In this paper,we construct a bounce inflation cosmological scenario in the framework of the modified symmetric teleparallel gravity,namely f(Q)theory,and investigate the tensor perturbations *** is well-known,the tensor perturbations generated in the very early Universe(inflation and pre-inflation regions)can account for the primordial gravitational waves(PGws)that are to be detected by the next generation of Gw *** discuss the stability condition of the tensor perturbations in the bounce inflation process and investigate in detail the evolution of the perturbation *** general form of the tensor power spectrum is obtained both for large as well as small scale *** a result,we show both kinds of modes(short or long wavelength modes),and the tensor spectrum may get a positive tilt in the parametric range where the tensor perturbation proves to be stable—this interestingly hints an enhancement of gravitational waves’amplitude in the background of the f(Q)bounce-inflation ***,we study the LQC-like scenario as a specific case of our model,in which,the primordial tensor power spectrum turns out to be nearly scale-invariant on both small and large scales.

关键词： bounce cosmology modified gravity cosmological perturbations

维普期刊数据库

Smoking of Carica papaya in Nigeria:The rationale,the public health effects and policies for intervention

在线全文

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2024年第3期17卷 95-96页

作者： Abolaji paul Adekeye Mental Health Department Federal Teaching HospitalIdo-EkitiEkiti StateNigeria Mental Health Department Afe Babalola UniversityAdo-EkitiEkiti StateNigeria

Psychoactive substance use is characterized by the habitual use of substances that have significant effects in altering the activities of neurotransmitters in certain regions of the ***,these alterations manifest as c... 详细信息

关键词： rational behaviour emotional

Surface engineering with ionic polymers on membranes for boron removal

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2024年第5期18卷 61-69页

作者： Xiting Zhang Chenyi Fang J paul Chen Sui Zhang Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore 117576Singapore Department of Civil and Environmental Engineering National University of SingaporeSingapore 119260Singapore College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

Removal of boric acid from seawater and wastewater using reverse osmosis membrane technologies is imperative and yet remains inadequately addressed by current commercial *** research efforts performed post-modification of reverse osmosis membranes to enhance boron rejection,which is usually accompanied by substantial sacrifice in water *** study delves into the surface engineering of low-pressure reverse osmosis membranes,aiming to elevate boron removal efficiency while maintaining optimal salt rejection and water *** were modified by the self-polymerization and co-deposition of dopamine and polystyrene sulfonate at varying ratios and *** surfaces became smoother and more hydrophilic after *** optimum membrane exhibited a water permeability of 9.2±0.1 L·m^(-2)·h^(-1)·bar^(-1),NaCl rejection of 95.8%±0.3%,and boron rejection of 49.7%±0.1% and 99.6%±0.3% at neutral and alkaline pH,*** water permeability is reduced by less than 15%,while the boron rejection is 3.7 times higher compared to the blank *** research provides a promising avenue for enhancing boron removal in reverse osmosis membranes and addressing water quality concerns in the desalination process.

关键词： membrane low-pressure reverse osmosis boron surface engineering

The great catastrophe: causes of the Permo-Triassic marine mass extinction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

National Science Review 2024年第1期11卷 37-50页

作者： paul B.wignall David P.G.Bond school of Earth & Environment University of Leeds school of Environmental Sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in South China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely Siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from Siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(whelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based Techniques

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Computers, Materials & Continua 2024年第3期78卷 3449-3467页

作者： Sherly Alphonse S.Abinaya Sourabh paul school of Computer Science and Engineering Vellore Institute of TechnologyChennai600127India school of Electronics Engineering Vellore Institute of TechnologyChennai600127India

The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial *** radiation cost and quality factor of the antenna are influenced by the size of the *** antennas allow for the circumvention of the bandwidth restriction for small *** parameters have recently been predicted using machine learning algorithms in existing *** learning can take the place of the manual process of experimenting to find the ideal simulated antenna *** accuracy of the prediction will be primarily dependent on the model that is *** this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard *** with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this *** prediction results of the proposed work are better when compared to the existing models in the literature.

关键词： Antenna pearson optimization bandwidth metamaterial