Carbon Dioxide, Bicarbonate and Carbonate Ions in Aqueous Solutions at Deep Earth Conditions

We investigate the effect of pressure, temperature and acidity on the composition of water-rich carbon-bearing fluids at thermodynamic conditions that correspond to the Earth's deep Crust and Upper Mantle. Our first-principles molecular dynamics simulations provide mechanistic insight into the hydration shell of carbon dioxide, bicarbonate and carbonate ions, and on the pathways of the acid/base reactions that convert these carbon species into one another in aqueous solutions. At temperature of 1000 K and higher our simulations can sample the chemical equilibrium of these acid/base reactions, thus allowing us to estimate the chemical composition of diluted carbon dioxide and (bi)carbonate ions as a function of acidity and thermodynamic conditions. We find that, especially at the highest temperature, the acidity of the solution is essential to determine the stability domain of carbon dioxide, bicarbonate and carbonate ions.Comment: 8 pages, 6 figure

(R) e (S)-2,2'-diidrossi-3,3'-dimetossi-5,5'-diallil-6,6'-dibromo-1,1'-bifenile un derivato chirale del <i>bis</i>-eugenolo

La presente comunicazione descrive la sintesi dell’equivalente bromurato chirale 2 del bis-eugenolo. La stabilità conformazionale del composto 2, e quindi la possibilità di isolare i due enantiomeri, potrebbe influenzare sostanzialmente la bioattivita’ della molecola

Bifenili idrossilati di origine naturale: building block per la preparazione di molecole di interesse biologico

Una delle ragioni del crescente interesse nei confronti dei bifenili idrossilati di origine naturale sono le importanti proprietà farmacologiche e biologiche manifestate da questi composti, in genere strutturalmente semplici. Le possibili variazioni geometriche determinate da trasformazioni chimiche della struttura bifenilica, rendono questa molecola un versatile prodotto di partenza per la preparazione di molecole bioattive

Sintesi e studi conformazionali di derivati 5,5'-disostituiti del 2,2'-dimetossi-1,1'-bifenile

In questo contesto, al fine di sintetizzare nuove strutture bifeniliche a chiralità assiale sono stati preparati i derivati 5,5’-disostituiti 1, 2, 3a-c a partire dal precursore comune 2,2’- diidrossi-1,1’-bifenile, un diolo commerciale a basso costo

Strategie di sintesi per la preparazione di bifenili ossidrilati chirali non racemi di interesse agrobiologico

L’attività di ricerca del gruppo è rivolta alla sintesi di bifenili con interessanti caratteristiche stereochimiche, ottenibili mediante metodi semplici e diretti al fine di un loro utilizzo nei sistemi biologici ed in agricoltura

Chemically modified β-cyclodextrins useful in developing biosensors of agricultural and food relevance

β-cyclodextrin (β-CD), a natural, non-toxic cycloeptaamilose macrocycle, is a useful biomatrix for immobilizing enzymes on a biosensor surface because of the affinity of its cavity for hydrophobic guest molecules (e.g., aminoacids). In this work β-CD has been successfully modified with different poly-carboxylic acids (PCAs) including 1,2,3,4-butanetetracarboxylic acid. Time activation, pH, pressure and stoichiometry were optimized in order to achieve selected substitutions on the macrocycle hydroxy groups. The modified β-CDs, prepared under mild conditions, are completely water-soluble and could be grafted on a biosensor surface

Combined Management of Apical Root Fracture and Avulsion of Two Maxillary Permanent Central Incisors: A Case Report

As a result of a skiing accident, a ten-year-old girl suffered combined injuries to both maxillary central incisor teeth (#1.1 and #2.1). The injuries were uncomplicated crown fractures, apical horizontal root fractures, and a severe extrusive luxation of the coronal segments of the teeth. Her mother repositioned the teeth immediately, resulting in good initial healing. Nine months later, the patient was referred to a specialist to manage the endodontic consequences of the trauma. The apexification treatment of the fractured roots, using a preformed apical barrier technique with bioactive cement, was the treatment of choice, administered to both the avulsed roots at two separate recall visits. The best option for managing the fractured apical segments was to continue with the follow-up, which was conducted to assess the overall case at 30 months. The fractured apexes remained normally positioned inside the socket and were asymptomatic (as they presumably maintained a physiological vascular-nerve supply and, consequently, their vitality), while the apexification treatment led to the healing of the periodontal tissues and to hard tissue formation in the area of the interrupted roots in the avulsed portion of the teeth. The management of traumatic injuries in teeth often requires multiple treatment approaches, because these injuries rarely represent one single type of trauma

Synthesis and study of polyhydroxylated phenol derivatives with potential cosmetic and phytoiatric applications

Tyrosinase (polyphenol oxidase, E.C. 1.14.18.1) and laccase (phenol oxidase, E.C. 1.10.3.2) are multifunctional copper-containing enzymes, that are keys in melanin biosynthesis, melanisation in animals and browning in plants. Our study is aimed to prepare new monomer and dimer phenol derivatives as potential inhibitors of melanin production starting from natural hydroxylated aromatic units

Tetrametossi bifenili come building blocks per la preparazione di bifenoli chirali non racemi

La struttura bifenilica ossidrilata è reminiscente di molte strutture di estratti naturali. Questi bifenili manifestano importanti attività antibatteriche, antivirali, antileucemiche, fungicide, tali da giustificare l'utilizzo della struttura bifenilica come building block per la preparazione di composti bioattivi