Light-induced reorientation and birefringence in polymeric dispersions of nano-sized crystals

Nanocrystals (50-250 nm) of a Palladium complex within a polyisobutylmethacrylate matrix were prepared by a phase separation method. In these dispersions, a light-induced birefringence with Deltan approximately 10(-3) was induced, without the application of an electric field. This effect was related to the photoconducting properties of the dispersion. Evidence for charge photogeneration without any applied field was obtained. The photorefractive behaviour of the material confirmed that the nanocrystals reorientation is a consequence of photoconducting properties. A light-generated electric field approximaely E 3 V/microm was estimated. These results illustrate the potential of materials with a nano-crystalline dispersion morphology as light-responsive media

Side-Chain Multifunctional Photoresponsive Polymeric Materials

The contribute reviews the recent literature concerning the state-of-the-art of the research on amorphous polymeric derivatives bearing side-chain photoactive moieties such as the azo-aromatic and the carbazole chromophore as functional groups, in addition to the presence of structural or chemical features suitable to also provide the macromolecules of chiral properties

Oral health status and periodontitis in Alzheimer's disease patients: A case control Study in a Sicilian rural community

Aim. Dementia is a common disorder among the elderly. Alzheimer’s disease (AD) is the most common cause of dementia. In addition to known risk factors (e.g. age and familiarity) of AD, recently it has been suggested a possible promoting role for chronic inflammatory infective diseases. Periodontal disease (PD) is a frequent chronic multi-bacterial infection involving the tissues supporting the teeth; in addition to promoting inflammation locally, the periodontal pathogens possess mechanisms able to influence the systemic balance of inflammatory mediators. Similarly to other systemic diseases (e.g. cardiovascular disease, diabetes, renal diseases and low birth weight), a possible link has been proposed between PD and the development and progression of AD. Aim of the present study was to evaluate the oral health status and the prevalence/severity of PD in a group of patients affected by AD compared to a control group of healthy subjects. Materials and methods. A case-controlled clinical trial was designed to compare patients with AD (Test group - T; n = 16; M: 8; F: 8, range age 64-93 yrs) with healthy controls (Control group - C; n = 16; M: 8; F:8; range age 64-92 yrs). The population study was named ZAP (Zabut Aging Project) and all participants, enrolled in a Sicilian rural community (Sambuca di Sicilia, AG, Italy), were matched for age and sex. Following variables were recorded: smoking and drinking habits, number of teeth, Decayed Missed Filled Teeth scoring (DMFT), measurement of the probing depth (CPI and PSR index). The association between AD and PD, socio-demographic and behavioural-clinical variables was assessed using the χ2 test or Fisher’s exact test, as appropriate. To measure the association level, crude OR and the 95% Confidence Interval (CI) were calculated. Statistical significance of the difference in the average DMFT between cases and controls was assessed using the Student’s t-test. A p value ≤0.05 was considered statistically significant. Results. One patient of T group was a smoker versus four of C group; four T patients were drinker versus two of C group. Seven of T group (43.7%) were totally edentulous, conversely only 2 (12.5%) of controls have the same condition (p=0.04). With respect to oral status, DMFT index was 23.7 ±9.0 in T patients versus 25.2±7.8 in controls (p=0.633). There were no significant differences between T and C groups regarding periodontal index: high PSR and CPI scores (>3) were recorded in 77.8% of AD patients and 46.1% of health cases (p >0.05). A similar distribution among two groups was observed regarding the other investigated variables (e.g. smoking and drinking habits). Conclusions. In this rural Sicilian adult/elderly community, poor oral health is frequent with a DMFT score higher than general population. The obtained data do not support the hypothesis of a major prevalence and severity of PD among AD patients. However, to confirm these preliminary results the recruitment of a wider sample size and further data, regarding proteomic salivary profiles and RT PCR-based microbiological investigation on sub-gingival plaque samples, still need in order to better clarify the role of PD and periodontal pathogens in the AD natural history

Multifunctional supramolecular dendrimers with an s-triazine ring as the central core: Liquid crystalline, fluorescence and photoconductive properties

Novel liquid crystal (LC) dendrimers have been synthesised by hydrogen bonding between an s-triazine as the central core and three peripheral dendrons derived from bis(hydroxymethyl)propionic acid. Symmetric acid dendrons bearing achiral promesogenic units have been synthesised to obtain 3:1 complexes with triazine that exhibit LC properties. Asymmetric dendrons that combine the achiral promesogenic unit and an active moiety derived from coumarin or pyrene structures have been synthesised in order to obtain dendrimers with photophysical and electrochemical properties. The formation of the complexes was confirmed by IR and NMR spectroscopy data. The liquid crystalline properties were investigated by differential scanning calorimetry, polarising optical microscopy and X-ray diffractometry. All complexes displayed mesogenic properties, which were smectic in the case of symmetric dendrons and their complexes and nematic in the case of asymmetric dendrons and their dendrimers. A supramolecular model for the lamellar mesophase, based mainly on X-ray diffraction studies, is proposed. The electrochemical behaviour of dendritic complexes was investigated by cyclic voltammetry. The UV/Vis absorption and emission properties of the compounds and the photoconductive properties of the dendrons and dendrimers were also investigated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.This work was supported by the seventh FP THE PEOPLE PROGRAMME, The Marie Curie Actions, ITN, no. 215884-2, the MINECO, Spain, (under Projects: CTQ2012-35692 and MAT2012-38538-CO3-01), which included FEDER funding, and the Aragón Government-FSE (Project E04). A.G. and R.T. acknowledge support from the European Community’s Seventh Framework Program (FP7 2007–2013) through the MATERIA Project (PONa3_00370) and from MIUR through the PRIN 2012JHFYMC project. M.B. acknowledges support from the EU through an ESR fellowship.Peer Reviewe

Striking Increase in Hole Mobility upon Metal Coordination to Triphenylene Schiff Base Semiconducting Multicolumnar Mesophases

Producción CientíficaThis paper reports the synthesis, liquid-crystal behavior, and charge-transport properties in the mesophase of triphenylene Schiff bases and their copper(II), nickel(II), and oxovanadium(IV) complexes. The thermal and electronic properties of the Schiff bases are modulated by coordination to the corresponding metal moieties, which have the ability to self-assemble into linear structures and help the alignment of the triphenylene columns. This produces two kinds of electronically nonconnected columnar regions, one purely organic and one more inorganic. The most remarkable effect is a striking charge mobility enhancement in the metal-containing mesophases, due to the contribution of the more inorganic columns: in comparison to values of hole mobility along the columnar stacking for the purely organic columnar mesophases, on the order of 10–7 cm2 V–1 s–1, these values jump to 1–10 cm2 V–1 s–1 in these hybrid inorganic/organic columnar materials.Ministerio de Ciencia, Innovación y Universidades (Project CTQ2017-89217-P)Junta de Castilla y León (Project VA038G18)Universidad del País Vasco / EHU (ProjectGIU18/146

High One-Dimensional Charge Mobility in Semiconducting Columnar Mesophases of Isocyano-Triphenylene Metal Complexes

Producción CientíficaThis paper reports the synthesis, liquid crystal behavior, and charge-transport properties in the mesophase of isocyano-triphenylene gold, copper, palladium, and platinum complexes [MX(CNR)] (CNR = 2-(6-(4-isocyanophenoxy)hexyloxy)-3,6,7,10,11-pentakisdodecyloxytriphenylene; M = Au, X = Cl, C6F5, C6F4OC10H21, CN; M = Cu, X = Cl), [(μ-4,4′-C6F4C6F4){Au(CNR)}2], [(μ-Cl2){Cu(CNR)2}2], and [MX2(CNR)2] (M = Pd, Pt; X = Cl, Br, I, and M = Pt, X = CN). The thermal and electronic properties of these materials are modulated by the metal fragment. The complexes that display columnar mesomorphism are those that support more than one triphenylene per molecule or those that produce a similar effect by dipole–dipole interactions between the metal groups. These circumstances improve the balance of favorable enthalpic interactions versus unfavorable entropic contributions into a columnar stacking. Hybrid inorganic/organic dual columnar mesophases with high SCLC hole mobility along the columnar stacking, above 1 cm2 V–1 s–1, have been found. It is worth noting that the dicyanoplatinum complex displays mesophase phosphorescence based on Pt···Pt interactions.Ministerio de Ciencia e Innovación (Proyect CTQ2014-52796-P

Semiconducting pi-extended discotic liquid-crystalline triindoles: studying their FET vs. SCLC mobilities

The field of organic electronics has experienced a vast development in the last few years, having the first generation of devices based in this technology already reached the market. Advances achieved in this field have been associated with the research of organic semiconductors able to transport charge carriers with a high mobility. However, finding organic semiconductors with the right balance between mobility and processability is still a challenge in the area. In this context, discotic liquid crystals, constituted by an aromatic central core surrounded by flexible alkyl tails, are among the most promising new candidates. Triindoles have been widely studied as a π-conjugated platforms in the construction of high mobility semiconducting liquid crystals. Three-fold oxidative cyclodehydrogenation of hexaphenyltriindole renders the significantly enlarged aromatic core, with structural characteristics of both triphenylene moieties and triindole. In this π-extended discotic core, the attachment of three flexible alkyl chains to the nitrogen atoms is sufficient to induce mesomorphism. The ratio of conducting versus isolating fraction is impressively enhanced when comparing to triindole liquid crystals, not only by enlarging the size of the central core but also by reducing the amount of isolating peripheral chains. In this presentation the electrical properties of the aforementioned semiconductor have been analyzed by applying two different methods: space-charge limited current (SCLC) measurements in a diode-like structure and field effect mobility measurements in a thin film transistor device. The mobility found on a diode type device is higher than that determined on thin film transistors, which can be understood by the high tendency of large π-conjugated molecules to deposit on surfaces with their extended core parallel to the substrate. This is demonstrated with a full analysis of the active layer of the thin film transistor, in order to analyze the molecular orientation in the semiconductor-dielectric interface, via Surface Enhanced Raman Spectroscopy (SERS). The observation of field effect behavior in a discotic liquid crystal processed by simple drop-casing suggests an increased dimensionality of charge transport by facilitating hopping between neighboring columns as a result of the large conducting/isolating ratio found in this discotic platform. Density Functional Theory (DFT) calculations have been performed in order to enlighten with more detail the charge-transport parameters at a molecular level.Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tec

Photoconductive properties and electronic structure in 3,5-disubstituted 2-(2′-pyridyl)pyrroles coordinated to a Pd(II) salicylideneiminate synthon

The synthesis and the electrochemical, photophysical, structural, and photoconductive properties of three new heteroleptic Pd(II) complexes with various 3′,5′- disubstituted-2-(2′-pyridil) pyrroles H(N^N) as coordinated ligands are reported. The coordination of the metal center was completed by a functionalized Schiff base H(O^N) used as an ancillary ligand. The [(N^N)Pd(O^N)] complexes showed highly interesting photoconductive properties which have been correlated to their electronic and molecular structures. Theoretical density functional theory (DFT) and time-dependent DFT calculations were performed, and the results were confronted with the organization in crystalline phase, allowing to point out that the photoconductive properties are mainly a consequence of an efficient intramolecular ligand-to-metal charge transfer, combined to the proximity between the central metal and the donor moieties in the solid-state molecular stacks. The reported results confirm that these new Pd(II) complexes form a novel class of organometallic photoconductors with intrinsic characteristics suitable for molecular semiconductors applications.Supported by Ministero dell’Istruzione, dell’Universitàe della Ricerca by the ELIOTROPO.Peer reviewe

Colorectal cancer after bariatric surgery (Cric-Abs 2020): Sicob (Italian society of obesity surgery) endorsed national survey

Background The published colorectal cancer (CRC) outcomes after bariatric surgery (BS) are conflicting, with some anecdotal studies reporting increased risks. The present nationwide survey CRIC-ABS 2020 (Colo-Rectal Cancer Incidence-After Bariatric Surgery-2020), endorsed by the Italian Society of Obesity Surgery (SICOB), aims to report its incidence in Italy after BS, comparing the two commonest laparoscopic procedures-Sleeve Gastrectomy (SG) and Roux-en-Y gastric bypass (GBP). Methods Two online questionnaires-first having 11 questions on SG/GBP frequency with a follow-up of 5-10 years, and the second containing 15 questions on CRC incidence and management, were administered to 53 referral bariatric, high volume centers. A standardized incidence ratio (SIR-a ratio of the observed number of cases to the expected number) with 95% confidence intervals (CI) was calculated along with CRC incidence risk computation for baseline characteristics. Results Data for 20,571 patients from 34 (63%) centers between 2010 and 2015 were collected, of which 14,431 had SG (70%) and 6140 GBP (30%). 22 patients (0.10%, mean age = 53 +/- 12 years, 13 males), SG: 12 and GBP: 10, developed CRC after 4.3 +/- 2.3 years. Overall incidence was higher among males for both groups (SG: 0.15% vs 0.05%; GBP: 0.35% vs 0.09%) and the GBP cohort having slightly older patients. The right colon was most affected (n = 13) and SIR categorized/sex had fewer values < 1, except for GBP males (SIR = 1.07). Conclusion Low CRC incidence after BS at 10 years (0.10%), and no difference between procedures was seen, suggesting that BS does not trigger the neoplasm development

Molecular Mechanisms Generating and Stabilizing Terminal 22q13 Deletions in 44 Subjects with Phelan/McDermid Syndrome

In this study, we used deletions at 22q13, which represent a substantial source of human pathology (Phelan/McDermid syndrome), as a model for investigating the molecular mechanisms of terminal deletions that are currently poorly understood. We characterized at the molecular level the genomic rearrangement in 44 unrelated patients with 22q13 monosomy resulting from simple terminal deletions (72%), ring chromosomes (14%), and unbalanced translocations (7%). We also discovered interstitial deletions between 17–74 kb in 9% of the patients. Haploinsufficiency of the SHANK3 gene, confirmed in all rearrangements, is very likely the cause of the major neurological features associated with PMS. SHANK3 mutations can also result in language and/or social interaction disabilities. We determined the breakpoint junctions in 29 cases, providing a realistic snapshot of the variety of mechanisms driving non-recurrent deletion and repair at chromosome ends. De novo telomere synthesis and telomere capture are used to repair terminal deletions; non-homologous end-joining or microhomology-mediated break-induced replication is probably involved in ring 22 formation and translocations; non-homologous end-joining and fork stalling and template switching prevail in cases with interstitial 22q13.3. For the first time, we also demonstrated that distinct stabilizing events of the same terminal deletion can occur in different early embryonic cells, proving that terminal deletions can be repaired by multistep healing events and supporting the recent hypothesis that rare pathogenic germline rearrangements may have mitotic origin. Finally, the progressive clinical deterioration observed throughout the longitudinal medical history of three subjects over forty years supports the hypothesis of a role for SHANK3 haploinsufficiency in neurological deterioration, in addition to its involvement in the neurobehavioral phenotype of PMS