1,721,099 research outputs found
Development of Multifunctional Nanomaterials for Biomedical Applications
Full text linkLa ricerca condotta in questa tesi si è focalizzata su due principali tematiche. La prima ha riguardato lo sviluppo di sensori e biosensori elettrochimici, basati su materiali nanostrutturati, per la determinazione di molecole di interesse biologico. La seconda è stata rivolta a definire nuove strategie da applicare nella terapia del cancro.
Per quanto riguarda la prima tematica, sono stati sviluppati sensori elettrochimici, basati su materiali 2D, tra cui metal organic frameworks, per la determinazione enzyme-less del glucosio. I nanomateriali sintetizzati, definiti nanozymes, sono in grado di catalizzare direttamente (cioè agiscono come enzimi artificiali) l'ossidazione del glucosio. I sensori sono stati impiegati per la determinazione di glucosio in tampone fosfato e in campioni di plasma diluito, sia a pH fisiologici che alcalini. Un biosensore, basato sull’impiego di substrati costituiti di flexible carbon cloths, è stato sviluppato per la determinazione del Covid-19 nella fase iniziale. A tale scopo, è stato immobilizzando sul substrato grafitico, un anticorpo capace di intercettare in modo selettivo la proteina spike del SARS-CoV-2. Il sensore sviluppato, essendo flessibile e “vestibile” si presta ad essere integrato in mascherine facciali protettive, per l'automonitoraggio dell'insorgenza dell'infezione Covid-19.
Il secondo argomento ha riguardato lo sviluppo di nuove strategie e sistemi terapeutici per curare il cancro ovarico grave di alto grado (HGSOC). A tal fine, sono stati studiati materiali con funzionalità operative diversificate. Un sistema innovativo di drug delivery sviluppato, comprendeva del materiale a base di hydroxylated-boron nitride-nanosheets, capace di incorporare la di doxorubicina e rilasciarla in prossimità del tumore. Inoltre, al fine di evitare alcuni problemi legati a questa modalità di somministrazione dei farmaci, sono stati sviluppati composti di tipo carrier-free, costituiti di farmaci con caratteristiche altamente idrofobiche (MAGL, composti 17, VS1 e VS10), per differenti target terapeutici (PIN1 &STARD3) di cancro ovarico. A tale scopo Le molecole dei farmaci molto idrofobiche sono state solubilizzate, riducendone contemporaneamente le dimensioni degli aggregati molecolari, con diversi tensioattivi, e quindi ricoperte con nanocristalli di albumina per ottenere sistemi di trasporto in vivo stabili e sicuri. È stato anche studiato e proposto per scopi pratici o clinici un nanomateriale autoterapeutico, avente cioè funzioni medicinali, che può agire come un "nano proiettile magico" privo di composti terapeutici extra o il cui funzionamento possa dipendere da stimoli esterni
Controlled, partially exfoliated, self-supported functionalized flexible graphitic carbon foil for ultrasensitive detection of SARS-CoV-2 spike protein
Full text linkThis paper reports on an ultrasensitive and label-free electrochemical immunosensor for monitoring the SARSCoV-2 spike protein (SARS-CoV-2 SP). A self-supported electrode, which can simultaneously serve as an antibody immobilization matrix and electron transport channel, was initially fabricated by a controlled partial exfoliation of a flexible graphitic carbon foil (GCF). Mild acidic treatment enabled the partial oxidation and exfoliation (down to a few layers) of the flexible GCF; this also provided a high percentage of oxygen functionality and an enhanced surface roughness. The substrate electrode was further functionalized with ethylenediamine (EDA) to provide a suitable platform with even a higher surface roughness, for the covalent immobilization of an anti-SARS-CoV-2 antibody. The change in the current response for the [Fe(CN)(6)](3-/4-) redox couple, induced by the binding of SARS-CoV-2 SP to the antibody immobilized on the electrode surface, was used to determine the SARS-CoV-2 SP concentration. The immunosensor thus prepared could detect SARSCoV-2 SP within 30 min with high reproducibility and specificity over a wide concentration range (0.2-100 ng/ mL). Detection limits of 25 pg/mL and 27 pg/mL were found in a phosphate buffer solution (pH 7.4), and diluted blood plasma, respectively. The immunosensor was also employed to detect SARS-CoV-2 SP in artificial human saliva
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Copper nitroprusside: An innovative approach for targeted cancer therapy via ROS modulation
Full text linkThe clinical application of nanomaterials for chemodynamic therapy (CDT), which generate multiple reactive oxygen species (ROS), presents significant challenges. These challenges arise due to insufficient levels of endogenous hydrogen peroxide and catalytic ions necessary to initiate Fenton reactions. As a result, sophisticated additional delivery systems are required. In this study, a novel bimetallic copper (II) pentacyanonitrosylferrate (Cu(II)NP, Cu[Fe(CN) 5 NO]) material was developed to address these limitations. This material functions as a multiple ROS generator at tumoral sites by self-inducing hydrogen peroxide and producing peroxynitrite (ONOO-) species. The research findings demonstrate that this material exhibits low toxicity towards normal liver organoids, yet shows potent antitumoral effects on High Grade Serous Ovarian Cancer (HGSOC) organoid patients, regardless of platinum resistance. Significantly, this research introduces a promising therapeutic opportunity by proposing a single system capable of replacing the need for H2O2, additional catalysts, and NO-based delivery systems. This innovative system exhibits remarkable multiple therapeutic mechanisms, paving the way for potential advancements in clinical treatments
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Iron nitroprusside as a chemodynamic agent and inducer of ferroptosis for ovarian cancer therapy
Full text linkChemoDynamic Therapy (CDT) is a powerful therapeutic modality using Fenton/Fenton-like reactions to produce oxidative stress for cancer treatment. However, the insufficient amount of catalyst ions and ROS scavenging activity of glutathione peroxidase (GPX4) limit the application of this approach. Therefore, a tailored strategy to regulate the Fenton reaction more efficiently (utilizing dual metal cations) and inhibit the GPX4 activity, is in great demand. Herein, a CDT system is based on dual (Fe2+ metals) iron pentacyanonitrosylferrate or iron nitroprusside (FeNP) having efficient ability to catalyze the reaction of endogenous H2O2 to form highly toxic OH species in cells. Additionally, FeNP is involved in ferroptosis via GPX4 inhibition. In particular, FeNP was structurally characterized, and it is noted that a minimum dose of FeNP is required to kill cancer cells while a comparable dose shows negligible toxicity on normal cells. Detailed in vitro studies confirmed that FeNP participates in sustaining apoptosis, as determined using the annexin V marker. Cellular uptake results showed that in a short time period, FeNP enters lysosomes and, due to the acidic lysosomal pH, releases Fe2+ ions, which are involved in ROS generation (OH species). Western blot analyses confirmed the suppression of GPX4 activity over time. Importantly, FeNP has a therapeutic effect on ovarian cancer organoids derived from High-Grade Serous Ovarian Cancer (HGSOC). Furthermore, FeNP showed biocompatible nature towards normal mouse liver organoids and in vivo. This work presents the effective therapeutic application of FeNP as an efficient Fenton agent along with ferroptosis inducer activity to improve CDT, through disturbing redox homeostasis
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