检索结果-南通市图书馆

Effect of BaF2 addition on luminescence properties of Er3+/Yb3+ co-doped phosphate glasses

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2018年第1期36卷 58-63页

作者： K.Linganna R.narro-García P.Manasa H.Desirena E.De la rosa c.K.Jayasankar Department of Physics Sri Venkateswara University Advanced Optical Lens Research center Korea Photonics Technology Institute (KOPTI) centro de Física Aplicada y Tecnología Avanzada UNAM centro de Investigaciones en Optica

Er3+/Yb3+co-doped phosphate glasses（P2O5-Al2O3-BaO-BaF2-K2O-Er2O3-Yb2O3） with varying BaF2content,were prepared by a conventional melt quenching technique and their spectroscopic properties were examined through the Raman, absorption, emission and decay measurements. Raman spectra(350-1400 cm-1) of the Er3+/Yb3+co-doped phosphate glasses with varying BaF2content, were recorded upon laser excitation at 785 nm. Near infrared luminescence spectra were measured in the1400-1600 nm region under 970 nm diode laser excitation and characteristic band was observed at1533 nm corresponding to4Ⅰ13/2→4Ⅰ15/2transition of Er3+ion. The decay curves for the4Ⅰ13/2level of Er3+ion, were measured and the lifetime is found to decrease from 7.94 to 7.70 ms when BaF2content increases from 0 to 8 mol% and then increases up to 7.83 ms with further increase in BaF2content（12 mol%）. The emission *** and figure of merit for the4Ⅰ13/2→4Ⅰ15/2transition of Er3+ion were evaluated and compared to the other host matrices. The upconversion luminescence was measured and intense red emission was observed for all the studied samples.

关键词： Er3+/Yb3+co-doped phosphate glasses Raman spectra Absorption and emission cross-sections Lifetime Rare earths

Environmental degradation through mining for energy resources:The case of the shrinking Laguna Santa rosa wetland in the Atacama Region of chile

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Energy Geoscience 2022年第2期3卷 182-190页

作者： Mohammad Ayaz Alam rosa Sepúlveda Departamento de Geología Facultad de IngenieríaUniversidad de AtacamaAvenida Copayapu 485CopiapoRegion de AtacamaChile

As the world strives to replace fossil fuels with clean energy e reflected by global surge in the number of electric vehicles e the environmental impact of mining all the lithium(Li)needed to enable such a transformation has become a problem in its own *** South America,the biggest problem is the excessive use of water in Li extraction process in one of the driest areas in the *** from causing severe friction over water rights between local communities and mining companies,it puts enormous pressure on the region's fragile and poorly understood wetland *** are one of the most threatened ecosystems on the Earth,despite their great importance as habitats for a vast number of species and corresponding to one of the most productive *** work is the outcome of an investigation on Laguna Santa rosa's(LSR)vulnerability resulting from ongoing metal mining operations in its surroundings that require a large volume of water extracted from local aquifers,in addition to a high evaporation rate in the *** groundwater-dependent wetland will soon be further vulnerable with the commencement of water-intensive Li mining at Salar de Maricunga,with the extraction project already having an environmental impact study *** of this wetland protected under the Ramsar convention and home to numerous wildlife species habiting this highland sector of the Andean cordillera is vital for the associated *** variation in the water surface area of LSR has been deciphered through the application of a Landsat-5 Thematic Mapper(TM)satellite image *** has been done both for the hydrological year 2016e2017 and 1993-2014 period.A decreasing trend in the water surface area of LSR,a hypersaline lake at the southern extreme of Salar de Maricunga,a salt flat in the Atacama Region of chile,was observed through the study of satellite images between 1993 and 2014,showing shrinking of this ***,this shrinking t

关键词： Laguna Santa rosa Salar de Maricunga Lithium Water Wetland Ecosystem

Development and assessment of a multifunctional chitosan-based coating applied on AZ31 magnesium alloy: corrosion resistance and antibacterial performance against Klebsiella Pneumoniae

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2021年第6期9卷 2133-2144页

作者： Emmanuel Mena-Morcillo Lucien Veleva Mariana cerda-Zorrilla Montserrat Soria-castro Juan c.castro-Alcátara rosa c.canul-Puc Applied Physics Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico Marine Resources Department Center for Research and Advanced Study(CINVESTAV-IPN)Carr.Ant.a Progreso Km.697310MeridaYucatanMexico

This work presents a simple method to functionalise the surface of AZ31 magnesium alloy by applying a duplex MgF_(2)/chitosan coating,which improves its corrosion resistance and provides it with some antibacterial ***,the effect of three chitosan solutions with different concentrations on the growth of the bacteria Klebsiella pneumoniae in nutritive medium(TSB)was evaluated by absorbance kinetics experiments,where the chitosan solution at 2%(m/V)was selected for the coating *** coating application,the AZ31 substrate was pretreated with hydrofluoric acid for 48 hours in order to form a MgF_(2)conversion ***,the coating was applied to the pretreated substrate through the dry-casting *** of the alloy in each surface condition(bare,pretreated,and pretreated+coated with chitosan)were exposed to simulated body fluid(SBF)for 21 days at 37°c,with the solution renewed every 24 hours and the wastes *** surfaces were characterised by SEM-EDS,and XPS after the immersion tests,whereas the stored solutions were employed to measure the change in the Mg-ions *** impedance spectroscopy and potentiodynamic polarisation were performed in each surface condition to compare their corrosion resistance in *** antibacterial activity of the functionalised surfaces was evaluated by the plate counting method and compared with bare *** results were correlated and demonstrate that the modified surface of AZ31 achieved a higher corrosion resistance when it was exposed to SBF,as well as a reduction of the bacterial growth during in vitro tests.

关键词： AZ31 chitosan coating Simulated body fluid corrosion Antibacterial activity

In vitro Metabolomic Approaches to Investigating the Potential Biological Effects of Phenolic compounds:An Update

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2017年第4期15卷 236-245页

作者： Ursula catalan Laura Barrubes rosa Maria Vails rosa Soila Laura Rubio Functional Nutrition Oxidation and Cardiovascular Diseases Group(NFOC-Salut)Technological Center of Nutrition and Health(CTNS)lnstitut d'lnvestigacio Sanitaria Pere Virgili(IISPV)Faculty of Medicine and ttealth SciencesUniversitat Rovira i VirgiliReus 43201Spain Food Technology Department Universitat de Lleida-AGROTECNIO CenterLleida 25198Spain

Dietary phenolic compounds （Pcs） have been receiving intercst lor their presumcd roles ill disease prevention. However, there is a lack of studies on the underlying molecular mechanisnls. In this regard, in vitro metabolomic approaches are suitable for the investigation o1 the molecular changes in response to Pc exposure. Up to date, the biological effects of Pcs have only been cxalnined for Pcs from rosemary （Rosmarinus officinalis）, olive oil, and reSVcl-atrol using cell-based mctabolomic approach, although transcriptomic and/or proteomic studies have also been conducted in the same in vi[ro cell experiment in some cases. Our integral analysis of the reviewed studies suggest that Pcs may be involved not only in basic cellular processes or macro-and micro-nutrient meta- bolism, but also in specific metabolic pathways that have been thoroughly investigated. These modulated pathways could have a clinical impact on neurodegenerativc diseases, type 2 diabetes, cancer, and cardiovascular diseases. In conclusion, the in vitro metabolomic approaches provide additional information of the molecular mechanisms involved in disease risk reduction of dietary Pcs. In order to elucidate the mechanisms of action of Pcs, more metabolomic cell-based studies are nccdcd and testing the physiological conjugated forms of Pcs in these cell systems could be of special interest.

关键词： cell-based Metabolomics Phenolic compounds Mechanism of action Disease prevention

Irritable bowel syndrome:A clinical review

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第34期20卷 12144-12160页

作者： rosa LS Soares Internal Medicine Department Faculty of MedicineFederal Fluminense UniversityRio de Janeiro 24030-210Brazil

Irritable bowel syndrome (IBS) remains a clinical challenge in the 21st century. It’s the most commonly diagnosed gastrointestinal condition and also the most common reason for referral to gastroenterology clinics. Its can affect up to one in five people at some point in their lives, and has a significantly impact of life quality and health care utilization. The prevalence varies according to country and criteria used to define IBS. Various mechanisms and theories have been proposed about its etiology, but the biopsychosocial model is the most currently accepted for IBS. The complex of symptoms would be the result of the interaction between psychological, behavioral, psychosocial and environmental factors. The diagnosis of IBS is not confirmed by a specific test or structural abnormality. It is made using criteria based on clinical symptoms such as Rome criteria, unless the symptoms are thought to be atypical. Today the Rome criteria III is the current gold-standard for the diagnoses of IBS. Secure positive evidence of IBS by means of specific disease marker is currently not possible and cannot be currently recommended for routine diagnosis. There is still no clinical evidence to recommend the use of biomarkers in blood to diagnose IBS. However, a number of different changes in IBS patients were demonstrated in recent years, some of which can be used in the future as a diagnostic support. IBS has no definitive treatment but could be controlled by non-pharmacologic management eliminating of some exacerbating factors such certain drugs, stressor conditions and changes in dietary *** traditional pharmacologic management of IBS has been symptom based and several drugs have been used. However, the cornerstone of its therapy is a solid patient physician relationship. This review will provide a summary of pathophysiology, diagnostic criteria and current and emerging therapies for IBS.

关键词： Irritable bowel syndrome clinical review Pathogenesis Diagnostic Treatment Biopsychosocial model

Analysis of hydrodynamic effects on biofilm thickness in fluidized-bed tapered bioreactors

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 48-57页

作者： Daniela Maria Koerich Leonardo Machado da rosa chemical Engineering Department University of Blumenau(FURB)3250 Sao Paulo Street89030-000 BlumenauSanta CatarinaBrazil

Fluidized beds in tapered geometries provide advantages such as a broad range of optimum operating ***,the dynamics of the flow inside these bioreactors is significantly more complex,as they promote non-uniform bioparticles *** this end,the cFD technique can give a detailed description of the flow in the ***,the aim of this work is to assess the influence of the hydrodynamic on the steady-state biofilm thickness through numerical simulations of liquid–solid fluidized *** geometries of tapered bioreactors in the operating conditions used to develop *** were run to solve the two-phase RANS equations using the open-source software OpenFOAM in *** SST k−ω model was used to estimate the turbulent features of the *** and bioparticles distribution inside the reactor were analyzed for different inlet velocities,while bioparticles collision frequency and shear stresses were evaluated for various operating *** comparison between the turbulent kinetic energy and the granular temperature indicated that the fluid flow is more turbulent than the bioparticles *** hydrodynamics influence on the steady-state biofilm thickness was assessed,and results led to the conclusion that biofilm is more sensitive to hydrodynamic shear stress than bioparticles collisions.

关键词： Liquid-solid fluidization Shear stress Particles collisions computational fluid dynamics Biofilm Tapered bioreactors

Searching for alternatives to brain regeneration

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 2021年第11期16卷 2198-2200页

作者： chiara La rosa Luca Bonfanti Neuroscience Institute cavalieri Ottolenghi(NIcO) OrbassanoItaly Department of Veterinary Sciences University of TurinGrugliascoItaly

Brain regeneration from an evolutionary perspective:Brain regeneration(the full restoration of tissue after loss from injury or disease)is the most sought after goal for researchers working in developmental *** also appears to be the most challenging to achieve when considering the mammalian *** remarkable regenerative capacities can be present in the central nervous systems of many non-mammalian vertebrates(e.g.,fish,amphibians),these kinds of processes appear to be dramatically reduced in mammals(Bonfanti,2011).

关键词： regeneration sought injury

capsule endoscopy and panendoscopy:A journey to the future of gastrointestinal endoscopy

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第10期30卷 1270-1279页

作者： Bruno rosa Josécotter Department of Gastroenterology Hospital da Senhora da OliveiraGuimarães 4835-044Portugal Life and Health Sciences Research Institute School of MedicineUniversity of MinhoBraga 4710-057Portugal IcVS/3B's PT Government Associate LaboratoryBraga 4710-057Portugal

In 2000,the small bowel capsule revolutionized the management of patients with small bowel ***,the technological development achieved by the new models of double-headed endoscopic capsules,as miniaturized devices to evaluate the small bowel and colon[pan-intestinal capsule endoscopy(PcE)],makes this non-invasive procedure a disruptive concept for the management of patients with digestive *** technology is expected to identify which patients will require conventional invasive endoscopic procedures(colonoscopy or balloon-assisted enteroscopy),based on the lesions detected by the capsule,i.e.,those with an indication for biopsies or endoscopic *** use of PcE in patients with inflammatory bowel diseases,namely crohn’s disease,as well as in patients with iron deficiency anaemia and/or overt gastrointestinal(GI)bleeding,after a non-diagnostic upper endoscopy(esophagogastroduodenoscopy),enables an effective,safe and comfortable way to identify patients with relevant lesions,who should undergo subsequent invasive endoscopic *** recent development of magnetically controlled capsule endoscopy to evaluate the upper GI tract,is a further step towards the possibility of an entirely non-invasive assessment of all the segments of the digestive tract,from mouth-to-anus,meeting the expectations of the early developers of capsule endoscopy.

关键词： Non-invasive endoscopy Panendoscopy Magnetically controlled capsule endoscopy crohn’s disease Digestive bleeding

Volatilomic fingerprinting from edible *** some impact compounds behind its attractiveness

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Food Bioscience 2022年第6期50卷 1988-1999页

作者： Sergio Izcara rosa Perestrelo Sonia Morante-Zarcero Isabel Sierra JoséS.câmara Departamento de Tecnología Química y Ambiental E.S.C.E.TUniversidad Rey Juan CarlosC/ Tulipán s/n28933MóstolesMadridSpain cQM – centro de Química da Madeira Universidade da MadeiraCampus da Penteada9020-105FunchalPortugal Departamento de Química Faculdade de Ciências Exatas e EngenhariaUniversidade da MadeiraCampus da Penteada9020-105FunchalPortugal

In recent years edible flowers emerged in gourmet cuisine,giving any dish the beauty of attractive colours,freshness,texture,and aromatic ***,they also constitute a potential source of phytochemical compounds associated with beneficial effects on human *** this work,the volatilomic fingerprinting of 4 different species of edible flowers[blue mallow(Malva sylvestris L.),pomegranate flower(Punica granatum L.),hibiscus(Hibiscus rosa-sinensis L.),and nasturtium(Tropaeolum majus L.)]used in gourmet dishes,was established,and comparatively *** volatile metabolites were extracted by solid-phase microextraction in headspace mode and identified by gas chromatography-mass spectrometry to understand the chemistry behind its attractiveness better.A total of 78 volatile metabolites,belonging to diverse chemical groups were *** mallow is mainly characterised by sesquiterpenoids(61.5%of the total volatile fraction),whereas in flowers from pomegranate,hibiscus,and nasturtium,terpenoids(56.6%),carbonyl compounds(88.0%)and organosulfur compounds(98.0%)are the dominant chemical groups,*** blue mallow flowers,τ-muurolene and valencene are the dominant volatiles,followed byα-cubebene andδ-*** flowers are rich in furfural and linalool,while the aldehydes 2-hexenal,hexanal and 2-octenal are dominant volatile metabolites in *** isothiocyanate,a potent antimicrobial agent,accounts for 98%of the total volatile fraction of nasturtium *** addition to flavour notes,some of the identified volatile metabolites present bioactive properties,which could be explored for application in the food,pharmaceutical and cosmetic *** volatile metabolites profiles combined with unsupervised principal component analysis facilitated the differentiation of the edible flowers under investigation,revealing the most related volatile metabolites of each sample,which can be used as markers for the authentication of the

关键词： Edible flowers Volatilomic fingerprint HS-SPME/Gc-MS Multivariate statistical analysis