1,160 research outputs found
On Ideas in Motion in Baghdad and Beyond
Note on Damien Janos (ed.), Ideas in Motion in Baghdad and Beyond. Philosophical and Theological Exchanges between Christians and Muslims in the Third/Ninth and Fourth/Tenth Centuries, (Islamic History and Civilization. Studies and Texts, 124), Brill: Leiden–Boston, 201
Destruction of dimethyl ether and methyl formate by collisions with He
To correctly model the abundances of interstellar complex organic molecules
(iCOMS) in different environments, both formation and destruction routes should
be appropriately accounted for. While several scenarios have been explored for
the formation of iCOMs via grain and gas-phase processes, much less work has
been devoted to understanding the relevant destruction pathways, with special
reference to (dissociative) charge exchange or proton transfer reactions with
abundant atomic and molecular ions such as He, H and HCO. By
using a combined experimental and theoretical methodology we provide new values
for the rate coefficients and branching ratios (BRs) of the reactions of He
ions with two important iCOMs, namely dimethyl ether (DME) and methyl formate
(MF). We also review the destruction routes of DME and MF by other two abundant
ions, namely H and HCO. Based on our recent laboratory measurements
of cross sections and BRs for the DME/MF + He reactions over a wide
collision energy range, we extend our theoretical insights on the selectivity
of the microscopic dynamics to calculate the rate coefficients in the
temperature range from 10 to 298 K. We implement these new and revised kinetic
data in a general model of cold and warm gas, simulating environments where DME
and MF have been detected. Due to stereodynamical effects present at low
collision energies, the rate coefficients, BRs and temperature dependences here
proposed differ substantially from those reported in KIDA and UDfA, two of the
most widely used astrochemical databases. These revised rates impact the
predicted abundances of DME and MF, with variations up to 40% in cold gases and
physical conditions similar to those present in prestellar coresComment: accepted for publication in Astronomy and Astrophysics (manuscript
no. AA/2018/34585), 10 pages, 3 figure
Idrotalciti Zn/Al intercalate con molecole biologicamente attive per il trattamento combinato di neoplasie
Le idrotalciti (HTlc), note anche come argille anioniche o idrossidi doppi lamellari, sono costituite da strati carichi positivamente con intercalati anioni di varia natura. Questo lavoro di tesi ha riguardato la sintesi e caratterizzazione di HTlc nanometriche con formula [Zn0,72Al0,28(OH)2] Br0,28•0,69H2O. Grazie allo loro biocompatibilità, stabilità e bassa tossicità, tali composti risultano particolarmente adatti alla veicolazione di farmaci. Pertanto, ho messo a punto la sintesi e intercalazione all’interno delle HTlc di due diverse sostanze: la norcantaridina (NCTD), una molecola organica antitumorale in grado di bloccare il ciclo cellulare in fase G2/M e la ftalocianina tetrasulfonata (ftl), una molecola fotosensibile anionica che illuminata a una specifica lunghezza d'onda, sviluppa sostanze citotossiche, quali specie radicaliche dell'ossigeno (ROS) e ossigeno di singoletto (1O2), in grado di uccidere le cellule malate. Questi nanocompositi, inoltre, sono stati caratterizzati in termini di capacità di loading e di rilascio nel tempo. Inoltre, sono stati effettuati test in vitro per valutare l’efficacia di questi composti su un panel di linee cellulari tumorali, ed è stato dimostrato che i farmaci caricati sulle HTlc sono più citotossici rispetto alle molecole libere, sia quando somministrati singolarmente che in combinazione
the arabic aristotle in the 10th century bagdad the case of yaiya ibn adi s commentary on metaph alpha elatton
Neste estudo, procura-se mostrar, através de um autor cristão do século 10, como comentários às obras de Aristóteles foram continuamente feitos, desde os gregos até Averróis. Por meio de alguns textos da Metafísica, é possível perceber que, mesmo sem ter contato direto com o original grego, foram cotejadas pelo autor diversas traduções, tanto do grego como do siríaco. Nesses casos, tratava-se, não apenas de tradução, mas também de comentário ao texto de Aristóteles. PALAVRAS-CHAVE – Aristóteles. Metafísica. Filosofia islâmica. Traduções para o árabe. Comentários
Exposure to the natural alkaloid Berberine affects cardiovascular system morphogenesis and functionality during zebrafish development
The plant-derived natural alkaloid berberine displays therapeutic potential to treat several pathological conditions, including dyslipidemias, diabetes and cardiovascular disorders. However, data on berberine effects during embryonic development are scarce and in part controversial. In this study, using zebrafish embryos as vertebrate experimental model, we address the effects of berberine treatment on cardiovascular system development and functionality. Starting from the observation that berberine induces developmental toxicity and pericardial edema in a time- and concentration-dependent manner, we found that treated embryos display cardiac looping defects and, at later stages, present an abnormal heart characterized by a stretched morphology and atrial endocardial/myocardial detachment. Furthermore, berberine affected cardiac functionality of the embryos, promoting bradycardia and reducing the cardiac output, the atrial shortening fraction percentage and the atrial stroke volume. We also found that, during development, berberine interferes with the angiogenic process, without altering vascular permeability. These alterations are associated with increased levels of vascular endothelial growth factor aa (vegfaa) mRNA, suggesting an important role for Vegfaa as mediator of berberine-induced cardiovascular defects. Altogether, these data indicate that berberine treatment during vertebrate development leads to an impairment of cardiovascular system morphogenesis and functionality, suggesting a note of caution in its use during pregnancy and lactation
Simian virus 40 in humans
Simian virus 40 (SV40) is a monkey virus that was administered to human populations by contaminated vaccines which were produced in SV40 naturally infected monkey cells
Stevia Genus: Phytochemistry and Biological Activities Update
The Stevia genus (Asteraceae) comprises around 230 species, distributed from the southern United States to the South American Andean region. Stevia rebaudiana, a Paraguayan herb that produces an intensely sweet diterpene glycoside called stevioside, is the most relevant member of this genus. Apart from S. rebaudiana, many other species belonging to the Stevia genus are considered medicinal and have been popularly used to treat different ailments. The members from this genus produce sesquiterpene lactones, diterpenes, longipinanes, and flavonoids as the main types of phytochemicals. Many pharmacological activities have been described for Stevia extracts and isolated compounds, antioxidant, antiparasitic, antiviral, anti-inflammatory, and antiproliferative activities being the most frequently mentioned. This review aims to present an update of the Stevia genus covering ethnobotanical aspects and traditional uses, phytochemistry, and biological activities of the extracts and isolated compounds.Fil: Borgo, Jimena. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Laurella, Laura Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Martini, María Florencia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Catalán, Cesar A. N.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Orgánica; ArgentinaFil: Sülsen, Valeria Patricia. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; Argentin
L’analogia dell’essere. Testi antichi e medievali
Il volume contiene i testi più significativi relativamente alla nascita e allo sviluppo della dottrina dell’analogia dell’essere. I passi sono riportati a fronte con traduzioni originali annotate e sono raccolti in due sezioni: quella di filosofia antica e tardoantica e quella di filosofia medievale araba e latina. La prima sezione comprende i principali testi aristotelici che della dottrina dell’analogia dell’essere hanno costituito l’origine, e i passi fra i più rilevanti della tradizione commentaristica antica e tardoantica, da Alessandro di Afrodisia (II-III sec. d.C) a Simplicio di Cilicia (VI sec. d.C.), nei quali è possibile individuare le prime fasi dello sviluppo di tale dottrina. La sezione di filosofia medievale araba e latina comprende passi scelti dei filosofi che rappresentano le tappe essenziali dello sviluppo della dottrina dell’analogia dell’essere nel medioevo arabo e latino, da al-Fārābī (m. 950 c.) a Tommaso d’Aquino (XIII sec.) a Tommaso de Vio, il “Gaetano” (XV-XVI sec.)
Conjugation of different immunogenic enterococcal vaccine target antigens leads to extended strain coverage
[Abstract] Enterococci have emerged as important nosocomial pathogens due to their resistance to the most commonly used antibiotics. Alternative treatments or prevention options are aimed at polysaccharides and surface-related proteins that play important roles in pathogenesis. Previously, we have shown that 2 Enterococcus faecium proteins, the secreted antigen A and the peptidyl-prolyl cis-trans isomerase, as well as the Enterococcus faecalis polysaccharide diheteroglycan, are able to induce opsonic and cross-protective antibodies. Here, we evaluate the use of glycoconjugates consisting of these proteins and an enterococcal polysaccharide to develop a vaccine with broader strain coverage. Diheteroglycan was conjugated to these 2 enterococcal proteins. Rabbit sera raised against these glycoconjugates showed Immunoglobulin G titers against the corresponding conjugate, as well as against the respective protein and carbohydrate antigens. Effective opsonophagocytic killing for the 2 sera was observed against different E. faecalis and E. faecium strains. Enzyme-linked immunosorbent assays against whole bacterial cells showed immune recognition of 22 enterococcal strains by the sera. Moreover, the sera conferred protection against E. faecalis and E. faecium strains in a mouse infection model. Our results suggest that these glycoconjugates are promising candidates for vaccine formulations with a broader coverage against these nosocomial pathogens and that the evaluated proteins are potential carrier proteins
Novel role of PKC epsilon in mitotic spindle stability
Mitosis is a highly regulated process characterized by dramatic and coordinated morphological changes to ensure the fidelity of chromosome segregation. Missegregation of mitotic chromosomes leads to a condition that underlies chromosomal instability(1), which is a hallmark of cancer. In order to assure symmetry and bipolarity of the cell division process, mitotic spindle microtubules properly segregate mitotic chromosomes (2). Among the several isoforms of serine/threonine kinases, PKCε is one of the best understood for its role as a transforming oncogene, and it has been found overexpressed in different types of tumors. In 2008, Saurin and colleagues demonstrated the involvement of PKCε in the regulation of the late stage of mitosis (3). Through its association with 14-3-3 at the midbody, PKCε is essential for the successful completion of cytokinesis, and the inhibition of functional PKCε-14-3- 3 complex leads to abscission failure and multinucleated phenotype in cells. In this study, we found that PKCε is involved in mitotic spindle stability. Using fluorescence microscopy, we found that the active form of PKCε (phosphorylated at Ser-729), colocalizes to the centrosome in cells in metaphase, where the mitotic spindle nucleation occurs. Furthermore, experiments of co-immunoprecipitation revealed that, when cells are synchronized in metaphase, PKCɛ is associated to ɣ-tubulin, a member of the tubulin superfamily localized to the microtubule organizing centers and is essential for microtubule nucleation from centrosomes. Consequently modulation of PKCɛ expression affects spindle stability: PKCɛ downregulation by specific shRNA results in mitotic spindle disorganization with a reduction of the amount of centrosomal and mitotic ɣ-Tubulin and αβ-tubulin fluorescence. Mitotic spindle formation assays using Nocodazole, known to interfere with the polymerization of microtubules, revealed that cells lacking PKCɛ were unable to regrow microtubules after depolymerization. These results reveal a novel role of PKCɛ in mitotic spindle stability, which likely determinant for genome stability
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