The development of anticancer diagnostic and therapeutic strategies is of crucial importance to improve efficacy and therapeutic specificity. Here, we describe the synthesis and characterization of fluorescent self-assembling nanomicelles (NMs) based on a biocompatible polysaccharide (cellulose, CE) functionalized with a tetraphenyl ethylene derivative (TPEHy) and loaded with Doxorubicin (DOX) with aggregation-induced emission (AIE) properties and pH-dependent drug release. We obtained CE-TPEHy-NMs with an average diameter of 60 ± 17 nm for unloaded NMs and 86 ± 25 nm for NMs loaded with DOX, respectively. Upon testing different conditions, we obtained an encapsulation efficiency of 86% and a loading capacity of 90%. A controlled dialysis experiment showed that the release of DOX after 48 h is minimal at pH 7.4 (11%), increasing at pH 6.5 (50%) and at its maximum at pH 4.5 (80%). The cytotoxicity of blank and loaded CE-TPEHy-NMs at increasing concentrations and different pH conditions was tested on a MG-63 human osteosarcoma cell line. Based on viability assays at pH 7.4, neither unloaded nor loaded CE-TPEHy-NMs exerted any inhibition on cell proliferation. At pH 6.5, proliferation inhibition significantly increased, confirming the pH-dependent release. We characterized and studied the performance of CE-based amphiphilic, biocompatible NMs for controlled drug release in acidic conditions, such as tumor microenvironments. Further studies are required to optimize their synthesis process and to validate their antitumoral properties in vivo.

Nine antibacterial di-methacrylate monomers based on bis-quaternary ammonium salts (bis-QAMs) were synthesized and structurally characterized. The biological activity of the bis-QAMs was tested in terms of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) on different bacterial strains achieving promising results and, in most cases, a complete bactericidal effect using a bis-QAM concentration lower than 1 mg/mL. Two of the structures showed comparable and superior activity against S. mutans than the commercial monomer 12-methacryloyloxydodecyl pyridinium bromide (MDBP). All the bis-QAMs here described were able to inhibit S. mutans biofilm formation at a concentration equal to the MIC value. From the analysis of the obtained data, some correlation regarding the structure and the antibacterial activity of the bis-QAMs could be drawn: a flexible alkyl C12 spacer between the two quaternary ammonium moieties increased the monomer antibacterial effect in comparison to the aromatic ones; the equilibrium between hydrophobic and hydrophilic moieties was directly correlated to the bactericidal range of action; the increase of the steric hindrance of the ammonium side groups might be both advantageous or disadvantageous to the antibacterial efficacy depending on the whole monomer chemical structure. Even though the possible correlation between the monomer structures and their bacteriostatic or bactericidal effect is under investigation, the monomers exhibited low cytotoxicity on human dental pulp stem cells, confirming their promising potential in the dental materials' field. STATEMENT OF SIGNIFICANCE: The use of dental resins with antibacterial monomers might prevent the formation of secondary caries at the restoration margins. For this purpose, a series of di-methacrylate bis-quaternary ammonium monomers (QAMs) was developed. Unlike antibacterial mono-methacrylate monomers already described in the literature, the synthesized di-methacrylate monomers have the potential of acting as cross-linkers stabilizing the polymeric network and bear two quaternary ammonium groups that increase their antibacterial ability. The QAMs exert bactericidal activity on both Gram(+) and Gram(-) bacterial strains maintaining at the same time good biocompatibility with the oral environment. Some structural elements of the monomers were clearly related to high antibacterial properties, and this can help design new active structures and better understand their mechanism of action.

The influence of the layer thickness and composite shade on the final color of Ceram.X composites (Dentsply Sirona) was tested, selecting five intermediate-translucency Ceram.X Universal shades, three high-translucency Ceram.X Duo "enamel" shades, and four low-translucency Ceram.X Duo "dentin" shades. Using cylindrical molds, 850 specimens were obtained, representing the whole array of possible Universal single specimens (in seven thicknesses, ranging from 1.0 to 4.0 mm in 0.5-mm increments) and Duo combinations. The CIELAB coordinates of each specimen were determined with a spectrophotometer. Different thicknesses and composites were compared with Clark's ΔE. The difference in color among specimens of different thicknesses was material-dependent. The thickness and shade of the composite markedly affected the color yield of the Ceram.X system. For each shade of the Universal systems, only one Duo enamel-dentin combination corresponded.

Objectives:The aim was to investigate the efficacy of citric acid and ethylenediaminetetraacetic acid (EDTA)-based treatments on smear layer removal and blood clot formation and stabilization. Method and materials: After scaling and root planing, 126 root samples were divided into seven groups treated with: deionized water; saline; citric acid solution; Ultradent Citric Acid gel; EDTA solution; EDTA-based PrefGel; or untreated. Each group was divided into three subgroups: I for the evaluation of smear layer removal and surface wettability, II and Ill for the evaluation of blood clot formation and stabilization in static or dynamic rinsing conditions. Results: Conditioning agent treatments increased surface wettability with respect to untreated samples (Ultradent: 45 +/- 1 degrees, P= 6.2 x 10(-3); EDTA: 36 +/- 5 degrees, P = 8.9 x 10(-7); PrefGel: 47 +/- 7 degrees, P = 3.2 x 10(-2)). Smear layer removal (30% to 60% with respect to untreated samples) was observed for all the conditioning agents. Clot was absent on untreated samples and samples treated with deionized water. Clot quality was significantly higher for samples treated with conditioning agents (P < .05) and similar between group II and III (P > .05). A statistically significant difference (P = .027) was observed for clot coverage of the saline group, comparing static and dynamic rinsing, confirming the positive effect of treatments on clot stabilization. Conclusions:The use of conditioning agents improves smear layer removal and clot formation and stabilization with respect to scaling and root planing procedure only, which is, however, considered an essential procedure to promote wound healing in periodontal surgery.

Severe dental erosion could be one of the complications of gastroesophageal reflux disease and food disorders such as bulimia nervosa. The aim of the present in vitro study was to evaluate the remineralization efficiency and the erosion prevention capability obtained by combining the use of Elmex Erosion Protection (Elm-EP) and GC Tooth Mousse (GC-TM) in cases of strongly eroded enamel surfaces. Twenty-four specimens of bovine tooth were superficially treated with hydrochloric acid to mimic severe erosion conditions. The specimens were divided into 3 groups accordingly to a different remineralizing treatment for 15 days: immersion in artificial remineralizing saliva, brushing with Elm-EP and brushing with Elm-EP in association with a daily application of GC-TM paste. After the remineralization procedures, the specimens were exposed to a treatment with acid. The effectiveness of the treatments were assessed by surface profilometric analysis and scanning electron microscopy at four different steps. Furthermore, the quantity of the Ca(2+)lost during erosion was determined. The combined action of Elm-EP and GC-TM led to a 50% roughness decrease of critically eroded dental surfaces. The tandem use of Elmex Erosion Protection and GC Tooth Mousse resulted a promising protecting strategy for the prevention of the dental mineral loss.

The aim of the present study was to characterize nanohybrid and nanofilled composites in terms of degree of conversion (DC), rate of cure (RC), microhardness (Vickers hardness number; VHN), depth of cure, and contraction stress (CS). Ceram.X® universal- A3, duo enamel E2, and duo dentin D3 composites were compared to Tetric EvoCeram® and FiltekTMSupreme XTE composites of equivalent dentin and enamel shades under a 40 s photopolymerization protocol. DC was measured by infrared spectroscopy, calculating RC from the kinetic curve. Top and bottom VHN were determined using a Vickers indenter, and bottom/top surface ratio (Vickers hardness ratio; VHR) calculated. CS vs. time was assessed by a universal testing machine and normalized for the specimen bonding area. All materials showed DC < 60%, Ceram.X® composites reaching higher values than the other composites of corresponding shades. RC at 5 s of photopolymerization was always higher than that at 10 s. All the Ceram.X® composites and the lighter-shaded Tetric EvoCeram® and FiltekTMSupreme XTE composites reached the RC plateau after 25 s, the remaining materials showed a slower kinetic trend. Tetric EvoCeram® and FiltekTMSupreme XTE composites displayed the softest and the hardest surfaces, respectively. Differently from darker-shaded materials, the universal and the three enamel-shaded composites resulted optimally cured (VHR > 80%). The tested composites differed in CS both during and after light cure, Tetric EvoCeram® and FiltekTMSupreme XTE composites displaying the highest and the lowest CS, respectively. Only the Ceram.X® universal-A3 reached a CS plateau value. The tested composites exhibited material-dependent chemo-mechanical properties. Increasing the curing time and/or reducing the composite layer thickness for dentin-shaded composites appears advisable.

Adhesive systems are resin-based materials that reach their final mechanical properties through a polymerization process. Previous literature correlated the failure of the adhesive interface to low polymer setting. Adhesives systems are elaborate mixtures of different molecules of both hydrophilic and hydrophobic nature, included in the formulation to adequately infiltrate the complex dental substrate or added to prolong the stability of the adhesive layer over time. Each adhesive component may influence the polymerization reaction of the material. Photopolymerization is a complex reaction that has several clinical implications, and besides the material composition, it is influenced by multiple factors, including the substrate characteristics, the operator technique, and the light cure unit properties. This review is focused on the analysis of factors that have a potential role in the setting of adhesive materials and thus the ultimate characteristics of the adhesive layer and the stability of the resin-dentin interface.

Photobiomodulation (PBM) is emerging as an effective strategy for the management of multiple inflammatory conditions, including oral mucositis (OM) in cancer patients who receive chemotherapy or radiotherapy. Still, the poor understanding of the mechanisms by which the light interacts with biological tissues and the heterogeneity of light sources and protocols employed worldwide significantly limits its applicability. Reactive oxygen species (ROS) are massively generated during the early phases of OM and play a major role in the pathogenesis of inflammation in general. Here, we report the results of a clinical and experimental study, aimed at evaluating the effect of laser light at different wavelengths on oxidative stress in vivo in oncologic patients suffering from OM and in vitro in two cell types abundantly present within the inflamed oral mucosa, neutrophil polymorphonuclear (PMN) granulocytes, and keratinocytes. In addition to standard ROS detection methods, we exploited a roGFP2-Orp1 genetically encoded sensor, allowing specific, quantitative, and dynamic imaging of redox events in living cells in response to oxidative stress and PBM. We found that the various wavelengths differentially modulate ROS production. In particular, the 660 nm laser light increases ROS production when applied either before or after an oxidative stimulus. In contrast, the 970 nm laser light exerted a moderate antioxidant activity both in the saliva of OM patients and in both cell types. The most marked reduction in the levels of ROS was detected in cells exposed either to the 800 nm laser light or to the combination of the three wavelengths. Overall, our study demonstrates that PBM exerts different effects on the redox state of both PMNs and keratinocytes depending on the used wavelength and prompts the validation of a multiwavelength protocol in the clinical settings.

The four-step conversion of a series of N-Boc-protected l-amino acid methyl esters into enantiopure N-Boc allylamines by a modified Julia olefination is described. Key steps include the reaction of a lithiated phenylalkylsulfone with amino esters, giving chiral β-ketosulfones, and the reductive elimination of related α-acetoxysulfones. The overall transformation takes place under mild conditions, with good yields, and without loss of stereochemical integrity, being in this respect superior to the conventional Julia reaction of α-amino aldehydes.

A new pseudopeptide epoxide inhibitor, designed for irreversible binding to HIV protease (HIV-PR), has been synthesized and characterized in solution and in the solid state. However, the crystal structure of the complex obtained by inhibitor-enzyme cocrystallization revealed that a minor isomer, with inverted configuration of the epoxide carbons, has been selected by HIV-PR during crystallization. The structural characterization of the well-ordered pseudopeptide, inserted in the catalytic channel with its epoxide group intact, provides deeper insights into inhibitor binding and HIV-PR stereoselectivity, which aids development of future epoxide-based HIV inhibitors.

Hydroformylation of fluorinated alkenes is an efficient method for the preparation of fluorinated functionalized building blocks for the synthesis of biologically active target structures. In this article we summarize known hydroformylation reactions of fluorinated olefins and we add new results from our research groups. Particular attention is paid to the remarkable influence of organofluorine substituents on catalyst activity, regio- and stereoselectivity of the hydroformylation reaction.

Two new chiral, enantiomerically pure, hybrid P-N ligands, namely (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octan-4-one (1) and (2R,5S)-2-phenyl-3-(2-pyridyl)-1,3-diaza-2-phosphanicyclo[3,3,0]octane (2), have been synthesized starting from L-proline. The two ligands differ in the presence or not of a carbonyl group in the diazaphosphane ring. Their coordination chemistry towards Pd(II) was studied by reacting them with [Pd(CH3)Cl(cod)]. A different behaviour was observed: ligand 2 shows the expected bidentate chelating behaviour leading to the mononuclear Pd-complex, while ligand 1 acts as a terdentate ligand giving a dinuclear species. The corresponding cationic derivatives were obtained from the palladium neutral complexes, both as mono- and dinuclear derivatives, and tested as precatalysts for styrene dimerization, yielding E-1,3-diphenyl-1-butene regio- and stereoselectively as the sole product. A detailed analysis of the catalytic behaviour is reported.

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A series of chiral HCNN ligands ((S)-1b-g) (S)-2-(1-aminoethyl)-6-(aryl)pyridine (aryl = 4-MeO-phenyl, 1b; 4-CF(3)-phenyl, 1c; 3,5-di-Me-phenyl, 1d; 3,5-di-CF(3)-phenyl, 1e; 1-naphthyl, 1f; 2-naphthyl, 1g) were synthesized starting from commercial 2-acetyl-6-bromopyridine (2), by a chemoenzymatic method involving the dynamic kinetic resolution of the corresponding secondary alcohol (rac-3). The conversion of the resulting (R)-3, obtained in 98% ee, into the homochiral amine ((S)-6), followed by Suzuki coupling with the appropriate arylboronic acids 7b-g, gave access to (S)-1b-g, isolated in 97% cc, with an overall yield up to 50%. The in situ generated pincer complexes [MCl(CNN)(PP)] (M = Ru, Os; PP = Josiphos diphosphine), prepared from [MCl(2)(PPh(3))(3)], (R,S)-Josiphos diphosphines, and the ligands (S)-1b-g, were found to efficiently catalyze the asymmetric transfer hydrogenation of acetophenone in 2-propanol at 60 degrees C and in the presence of NaOiPr. On the basis of these data, the 2-naphthyl ruthenium and osmium derivatives [RuCl(CNN)((R,S)-Josiphos*)] (8) (HCNN = (S)-1g) and [OsCl(CNN)(PP)] (PP = (R,S)-Josiphos, 9, and (R,S)-Josiphos*, 10) were isolated from [MCl(2)(PPh(3))(3)], (R,S)Josiphos diphosphines, and the ligand (S)-1g. Complexes 8 and 10, displaying the correctly matched chiral PP and CNN(-) ligands, are highly active and productive catalysts for the transfer hydrogenation of alkyl aryl ketones and methyl pyridyl ketones with TOE = 10(5)-10(6) h(-1), using 0.005 mol % of catalysts and achieving up to 99% ee. The comparison of the catalytic activity of these pincer complexes shows that Ru and Os derivatives display similar rate and enantioselectivity.

Chiral orthometalated osmium complexes [OsCl(CN'N)(PP)] {PP = (S,R)-Josiphos type diphosphane} based on 2-aminomethylbenzo[h]quinoline ligands (HCN'N) were prepared by reaction of [OsCl(2)(PPh(3))(3)] with a Josiphos diphosphane and a HCN'N ligand in the presence of NEt(3). Ruthenium and osmium complexes [MX(CN'N)(PP)] (M = Ru, Os; X = Cl, OCH(p-C(6)H(4)F)(2); PP = dppb, (S,R)-Josiphos), in the presence of KOtBu, efficiently catalyze the chemoselective hydrogenation (H(2) = 5 atm) of aromatic and aliphatic ketones to secondary alcohols in methanol or methanol/ethanol mixtures, when a S/C ratio of 10000-50000 is used. With use of these chiral phosphanes, alkyl aryl ketones have been reduced with ee values up to 99% and turnover frequencies (TOFs) up to 5.6 x 10(4) h(-1).