检索结果-南通市图书馆

Polyelectrolyte complexes between Hyperbranched and Linear Polysaccharides: Fucoidan/chitosan

chinese Journal of Polymer Science 2024年第4期42卷 468-479页

作者： Ekaterina R.Gasilova Daria n.Poshina Aleksandra O.Sitnikova natalia n.Saprykina Yury A.Skorik Institute of Macromolecular compounds of the Russian Academy of Sciences Bolshoi VO 31St.Petersburg199004Russian Federation

Polyelectrolyte complexes(PEcs)of hyperbranched(HB)and linear polysaccharides are promising as more effective encapsulation agents compared to PEcs formed by linear *** investigated the PEcs between the HB anionic polysaccharide fucoidan(FUc)and the cationic linear polysaccharide chitosan(cS).The FUc had a molecular weight(MW)of 30×*** PEcs were prepared in three solvents(water,0.01 and 0.1 mol/L acetic acid)with cS of MW of 15,110 and 170 kDa,and deacetylation degrees(DDA)of 70%and 97%.The structures of the PEcs and the initial FUc were investigated by multi-angle static and dynamic light *** the FUc contained 18 wt%of—OSO3 groups and 5 wt%of uronic acid units,it was a“strong-weak”copolyanion,so the HB macromolecules of the FUc formed nanogel particles in 0.1 mol/L AcOH and open branched structures in water,as confirmed by the Kratky *** mixing the solutions of original components,the PEc structures underwent an equilibration period,the duration of which increased with the MW of *** the charge stoichiometry was approached,the PEcs shrank;the fractal dimension approached unity,indicating the side-by-side packing of adjacent FUc branches with the help of *** aggregation in the vicinity of the charge compensation was hardly observed,as it occurred in a very narrow *** PEc content at theζ-potential inversion depended on solvents’pH and the DDA of *** the extreme case of core-shell PEcs in 0.1 mol/L AcOH,obtained by mixing FUc nanogels with the solutions of high MW cS of 97%DDA,the protruding tails of cS formed a positively charged shell in the whole range of FUc content(10 wt%ccanning electron microscopy and atomic force microscopy images of dried samples were discussed in relation to the light scattering results.

关键词： Polyelectrolyte complexes chitosan Hyperbranched fucoidan Light scattering

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Long-term monitoring reveals the effect of precipitation and silviculture on nothofagus regeneration in northern Patagonia mixed forests

引用

Ecological Processes 2024年第2期13卷 103-117页

作者： Georgina Sola camila Mateo Alejandro Dezzotti Paula Marchelli Hernán Attis Beltrán Renato Sbrancia Luis chauchard Marcelo González Pe?alba Martín Lara Verónica El Mujtar consejo nacional de Investigaciones científicas y Técnicas (cOnIcET ) Asentamiento Universitario San Martín de los Andes (AUSMA-Unco) Instituto de Investigaciones Forestales y Agropecuarias Bariloche (IFAB) Instituto Nacional de Tecnología Agropecuaria (INTA) Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET ) Departamento de conservación y Manejo Parque Nacional Lanín- Administración de Parques Nacionales (PNL-APN)

Background Tree regeneration is a key component of resilience because it promotes post-disturbance recovery of forests. northwestern Patagonia from Argentina is occupied by nothofagus alpina（na）, n. obliqua（no）, and n. dombeyi（nd） forests that grow along an intense precipitation gradient, managed throughout shelterwood silvicultural system by technicians of the Lanin natural Reserve. The objective of this study was to evaluate the influence of seeding cuttings over the dynamics of nothofagus mixed forests across landscape（precipitation gradient） based mainly on the composition and abundance of tree regeneration, permanent sampling plots and generalized linear mixed models. In particular, we analysed:（i） the structure of sexual and asexual regeneration during nd > 20 years after harvest（the dynamics of managed forests）, and（ii） the structure of sexual regeneration in primary and managed forests after > 20 years of harvest（the effect of silviculture）.Results nd was the most abundant species in the regeneration of managed forests during all periods in both sites despite its lower contribution to the adult cohort. During the 10–20 years period after harvest, the humid site exhibited higher regeneration density than the mesic site(120,000 and 6000 ind ha-1, respectively), and it decreased afterwards. The number of established regeneration（> 2 m height） was lower for na in the mesic site and for no in the humid site(0 and 57 ind ha-1, respectively). However, in comparison to no, na showed a higher number of sprouted stumps and sprouts per stump, and a higher sprout height in the mesic site. no exhibited higher sprout mortality in the humid site. Finally, the regeneration of primary forests showed lower density and height, and a more balanced composition than that of managed *** The silvicultural effects on the mixed forest regeneration dynamics was strongly influenced by the condition of sites. Therefore, management prescriptions should be adj

关键词： nothofagus alpina nothofagus obliqua nothofagus dombeyi Basal sprouting Shelterwood silvicultural system Ecological resilience

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Effects of synthesis parameters on the performance of crosslinked co-polymers with clays for conformance control

引用

Petroleum Research 2024年第1期9卷 98-108页

作者： A.A.Roslan n.A.A.Aziz n.F.A.Deraman I.Dzulkarnain Petroleum Engineering Department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia chemical Engineering Department Centre of Research Enhanced Oil Recovery(COREOR)Universiti Teknologi PETRONASSeri IskandarPerakMalaysia

conformance control or water shut-off is a technique used to improve oil *** conformance control,polymers block high permeability water areas and redistribute water drive toward unswept oil *** this study,co-polymers(denoted ATP-PGV/AM-co-AMPS)were synthesized using acrylamide(AM)and 2-acrylamide-2-methylpropane sulfonic acid(AMPS)as the monomers,polyethylene glycol(PEG)-200 and methylenebisacrylamide(MBA)as the crosslinkers,attapulgite(ATP)and bentonite(PGV)as the clay types,and ammonium persulfate(APS)as the initiator,in addition to paraffin oil and *** were synthesized using inverse emulsion polymerization with different concentrations of monomers,crosslinkers,and clays,and they were characterized using Fourier-transform infrared(FTIR)spectroscopy and scanning electron microscopy(SEM)with energy dispersive X-ray spectroscopy(EDX).FTIR spectra of the samples confirmed the existence of sulfonate and hydroxyl groups,which are important for polymer ***-EDX images indicated that the morphology and elemental composition were different before and after swelling,confirming the occurrence of ***,samples were placed in sodium chloride solution(20,000 ppm)for 7 days to evaluate swelling at both room temperature and 90°*** analysis(TGA)and differential scanning calorimetry(DSc)were used to determine the thermal characteristics of the ***,rheological measurements were used to assess the deformation and rheological behavior of the *** results showed that after 1 day,good swelling without loss of mechanical strength was achieved with the composite synthesized using 10%AM,15%AMPS,6%PGV,and 10%ATP.

关键词： Polymer clay Water shut-off conformance Swelling

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Psychological consequences of a diagnosis of infertility in men:a systematic analysis

引用

Asian Journal of Andrology 2024年第1期26卷 10-19页

作者： Sarah n Biggs Jane Halliday Karin Hammarberg Reproductive Epidemiology Murdoch Children's Research InstituteMelbourne 3052Australia Department of Paediatrics University of MelbourneMelbourne 3052Australia Public Health and Preventative Medicine Monash UniversityMelbourne 3004Australia Victorian Assisted Reproductive Treatment Authority Melbourne 3000Australia

Almost half of infertility cases involve male *** the consequence of a diagnosis of male infertility,as a sole or partial contributor to the couples'infertility,to the mental health of men is required to ensure clinical care meets their psychological *** aim of this systematic analysis was to synthesize the evidence regarding whether men diagnosed with male factor infertility experience greater psychological distress than(1)men described as fertile and(2)men in couples with other infertility *** databases were searched using a combination of Medical Subject Headings(MeSH)headings and keywords relating to male infertility and psychological *** search yielded 1016 unique publications,of which 23 were included:8 case-control,14 prospective cohort,and 1 data linkage *** aspects of psychological distress were identified depression,anxiety,self-esteem,quality of life,fertility-related stress,general psychological stress or well-being,and psychiatric ***-control studies reported that men with male factor infertility have more symptoms of depression,anxiety and general psychological distress,worse quality of some aspects of life,and lower self-esteem than *** men with male factor infertility were compared to men in couples with other causes of infertility,there were few differences in the assessed aspects of psychological *** methodological limitations within the studies,this systematic analysis suggests that the experience of infertility,irrespective of its cause,negatively affects men's mental health and demonstrates the need for assisted reproduction technology(ART)providers to consider men undergoing assisted reproduction as individuals with their own unique support needs.

关键词： anxiety depression infertility male mental health quality of life

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Detection of 4p16.3 deletion and 11p15.5p15.4 gain in a boy by comparative genomic hybridization array:A case report

引用

World Journal of clinical cases 2024年第8期12卷 1517-1522页

作者： Işın Kaya Medical Genetics Bakırçay UniversityÇiğli Education ve Training Hospitalİzmir 35620Turkey

BAcKGROUnD nonallelic homologous recombination(nAHR)of segmental duplications or low copy repeats(LcRs)result in DnA gain/loss and play an important role in the origin of genomic *** SUMMARY A 3-year-old boy was referred for genetic *** genomic hybrid-ization array analysis revealed a loss of 3776 kb in the 4p16.3 chromosomal region and a gain of 3201 kb in the 11p15.5p15.4 chromosomal *** Genomic imbalances caused by nAHR in LcRs result in deletion and duplication syndromes.

关键词： Wolf-Hirschhorn syndrome Silver-Russell syndrome Recurrent rearrangements case report

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Role of marine natural products in the development of antiviral agents against SARS‑coV‑2:potential and prospects

引用

Marine Life Science & Technology 2024年第2期6卷 280-297页

作者： D.P.nagahawatta n.M.Liyanage Thilina U.Jayawardena H.H.A.c.K.Jayawardhana Seong‑Hun Jeong Hyung‑Jun Kwon You‑Jin Jeon Department of Marine Life Sciences Jeju National UniversityJeju 690-756Republic of Korea Department of chemistry Biochemistry and PhysicsUniversitédu QuébecàTrois-RivièresTrois-RivièresQC G8Z 4M3Canada Marine Science Institute Jeju National UniversityJeju 63333Republic of Korea Functional Biomaterial Research center Korea Research Institute of Bioscience and BiotechnologyJeongeup-siRepublic of Korea

A novel coronavirus,known as severe acute respiratory syndrome coronavirus 2(SARS-coV-2),has surfaced and caused global concern owing to its ***-coV-2 is the causative agent of coronavirus disease 2019;however,it was only discovered at the end of the year and was considered a pandemic by the World Health ***,the develop-ment of novel potent inhibitors against SARS-coV-2 and future outbreaks is urgently *** naturally occurring bioactive substances have been studied in the clinical setting for diverse *** intricate infection and replication mechanism of SARS-coV-2 offers diverse therapeutic drug targets for developing antiviral medicines by employing natural products that are safer than synthetic *** natural products(MnPs)have received increased attention in the development of novel drugs owing to their high diversity and ***,this review article investigates the infection and replication mechanisms,including the function of the SARS-coV-2 genome and ***,we highlighted anti-SARS-coV-2 therapeutic intervention efforts utilizing MnPs and predicted SARS-coV-2 inhibitor design.

关键词： SARS-coV-2 Marine natural products Drug targets Inhibitors

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatic perivascular epithelioid cell tumors:Benign,malignant,and uncertain malignant potential

引用

World Journal of Gastroenterology 2024年第18期30卷 2374-2378页

作者： Marcelo Fabián Amante División Patología Hospital General de Agudos Cosme ArgerichBuenos Aires C1155AHAArgentina División Patología Hospital Alemán de Buenos AiresBuenos Aires C1155AHAArgentina

In 2013,the World Health Organization defined perivascular epithelioid cell tumor(PEcoma)as“a mesenchymal tumor which shows a local association with vessel walls and usually expresses melanocyte and smooth muscle markers.”This generic definition seems to better fit the PEcoma family,which includes angiomyolipoma,clear cell sugar tumor of the lung,lymphangioleiomyomatosis,and a group of histologically and immunophenotypically similar tumors that include primary extrapulmonary sugar tumor and clear cell myomelanocytic *** cell tumors with this immunophenotypic pattern have also had their malignant variants *** localizing to the liver,preoperative radiological diagnosis has proven to be very difficult,and most patients have been diagnosed with hepatocellular carcinoma,focal nodular hyperplasia,hemangioma,or hepatic adenoma based on imaging *** of a malignant variant of the liver have been ***,reports of malignant variants of these lesions have increased in recent ***,we support the use of the Folpe criteria,which in 2005 established the criteria for categorizing a PEcoma as benign,malignant,or of uncertain malignant *** they are not considered ideal,they currently seem to be the best approach and could be used for the categorization of liver tumors.

关键词： PEcomas Liver Pathology Malignant Benign Uncertain malignant potential

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

contributions to the knowledge of Antarctodon sobrali(Mammalia:Astrapotheria)from the Eocene of Antarctica

引用

Advances in Polar Science 2024年第1期35卷 48-62页

作者： Javier n.GELFO consejo nacional de Investigaciones científicasy Técnicas(cOnIcET) Buenos Aires C1425FQBArgentina División Paleontología Vertebrados Museo de La PlataFacultad de Ciencias Naturales y Museo de La PlataUniversidad Nacional de La PlataLa Plata B1900FWAArgentina

The Astrapotheria constitutes one of the five orders of extinct South American native ungulates,with a fossil record that also extends to the Eocene of the Antarctic *** contrast to the abundant specimens known for litoptern Sparnotheriodontidae and metatherians,astrapotheres are represented by scant remains assigned to the endemic Antarctodon sobrali and indeterminate astrapotheres,restricted to levels 35c_(u0)and 35n of the cucullaea I Allomember of the La Meseta *** discovery of alower molar assignable to this species in the Eocene levels of Seymour(Marambio)Island,enables a revision of the diagnosis and the homologies of the dental characters used to describe this taxon.A reanalysis of its phylogenetic relationships reveals the nearly simultaneous presence of basal astrapotheres in the early Eocene of Itaboraí(Brazil),Patagonia,and West *** taxa are characterized by lacking dental specializations usually associated with more abrasive diets like terminal forms of Uruguaytheriinae and *** appears to have thrived on the Antarctic continent during the Early Eocene climatic Optimum within the paleoclimatic context of a hot-house *** present conditions in Antarctica where no terrestrial mammals inhabit,the early Eocene climate was characterized by warmer temperatures and a biologically diverse environment rich in primary producers,dominated by nothofagus forests,encompassing both deciduous and evergreen forests,which supported a diverse assemblage of continental vertebrates.

关键词： Astrapotheria Antarctodon Eocene Seymour Island La Meseta Formation

来源：

维普期刊数据库

同方期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

nanomotion of bacteria to determine metabolic profile

引用

nanotechnology and Precision Engineering 2024年第1期7卷 1-9页

作者： S.n.Pleskova E.V.Lazarenko n.A.Bezrukov R.n.Kriukov A.V.Boryakov M.E.Dokukin S.I.Surodin Research Laboratory of Scanning Probe Microscopy Lobachevsky State University of Nizhny NovgorodNizhny Novgorod 603950Russia Department of nanotechnology and Biotechnology Nizhny Novgorod State Technical University n.a.R.E.AlekseevNizhny Novgorod 603950Russia Sarov Physics and Technology Institute National Research Nuclear University MEPhISarov 607186Russia

In addition to their visible motion such as swimming(e.g.,with the help ofﬂagella),bacteria can also exhibit nanomotion that is detectable only with highly sensitive instruments,and this study shows that it is possible to detect bacterial nanomotion using an AFM detection *** results show that the nanomotion characteristics depend on the bacterial strain,and that nanomotion can be used to sense the metabolic activity of bacteria because the oscillations are sensitive to the food preferences of the bacteria and the type of surrounding medium.

关键词： nanomotion Bacteria cantilever Oscillation Atomic force microscopy Metabolism

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Using fused filament fabrication to improve the tribocorrosion behaviour of 17-4 PH SS in comparison to other metal forming techniques

引用

Friction 2024年第10期12卷 2325-2343页

作者： cristina GARcÍA-cABEZÓn Juan Alfonso nARAnJO celia GARcÍA-HERnÁnDEZ cristina BERGES Gemma HERRAnZ Fernando MARTÍn-PEDROSA Materials Engineering E.I.I.Universidad de ValladolidValladolid 47011Spain InEI-Escuela Técnica Superior de Ingeniería Industrial(ETSII) Universidad de Castilla La ManchaCastilla-La Mancha 13071Spain

Fused filament fabrication(FFF)is one of the additive manufacturing processes which has gained more interest because of its simplicity and *** technology is similar to the conventional metal injection moulding(MIM)process,consisting of the feedstock preparation of metal powder and polymer binders,followed by layer-by-layer 3D printing(FFF)or injection(MIM)to create green parts and,finally,debinding and ***,both technologies provide near-dense *** work presents an in-depth study of the processing method’s *** porosity,microstructure,hardness,corrosion,and tribocorrosion behaviour are compared for 17-4 PH SS samples processed from powder by additive manufacturing using FFF and MIM,as well as conventional powder metallurgy(PM)*** samples exhibited the highest macro and microhardness,while corrosion behaviour was similar for both MIM and FFF samples,but superior in comparison to conventional PM ***,the FFF-as fabricated samples displayed a significant improvement in tribocorrosion resistance that could be explained by the higher proportion of delta ferrite and retained austenite in their microstructure.

关键词： 17-4 PH SS fused filament fabrication(FFF) metal injection moulding(MIM) corrosion behaviour powder metallurgy(PM) tribocorrosion behaviour

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：