Newly generated cells are increased in hippocampus of adult mice lacking a serine protease inhibitor

Background  

Neurogenesis in the hippocampal dentate gyrus and the subventricular zone occurs throughout the life of mammals and newly generated neurons can integrate functionally into established neuronal circuits. Neurogenesis levels in the dentate gyrus are modulated by changes in the environment (enrichment, exercise), hippocampal-dependent tasks, NMDA receptor (NMDAR) activity, sonic hedgehog (SHH) and/or other factors.     

Dicyanoperylene-diimide thin-film growth: a combined optical and morphological study

N,N′-bis (n-octyl)-dicyanoperylene-3,4:9,10-bis(dicarboximide) (PDI8-CN₂) molecules represent an important example of novel n-type organic materials for realization of air-stable n-channel organic thin film transistors. In this work, the growth by evaporation of PDI8-CN₂ thin films deposited on silicon/silicon dioxide substrates has been investigated as a function of the film thickness through the combination of optical and morphological analyses. A continuous transition from two-dimensional to three-dimensional growth is observed at increasing thickness, accompanied by a modification of the photoluminescence spectrum of the films. Correlations between morphology and optical emission (photoluminescence) of the films are evidenced: namely, an emission band, red shifted with respect to the excitonic transition, emerges at increasing thickness. Time-resolved photoluminescence analysis demonstrates that the decay kinetics of such a band is different from the one associated with exciton recombination. Such a feature may thus represent a useful signature of defect-related trap states.     

Degradation Products from Naturally Aged Paper Leaves of a 16th‐Century‐Printed Book: A Spectrochemical Study

In this work, we present a wide‐range spectrochemical analysis of the degradation products from naturally aged paper. The samples obtained from wash waters used during the de‐acidification treatment of leaves from a 16th‐century‐printed book were analysed through NMR, IR, Raman UV/Vis, EPR and X‐ray fluorescence (XRF) spectroscopy and HPLC‐MS and inductively coupled plasma (ICP) analysis. By these methods we also studied some of the previous samples treated by acidification (sample AP) and catalytic hydrogenation (sample HP). Crossing all the data, we obtained precise indications about the main functional groups occurring on the degraded, water‐soluble cellulose oligomers. These results point out that the chromophores responsible for browning are conjugated carbonyl and carboxyl compounds. As a whole, we show that the analysis of wash waters, used in the usual conservation treatments of paper de‐acidification, gives much valuable information about both the conservation state of the book and the degradation reactions occurring on the leaves, due to the huge amount of cellulose by‐products contained in the samples. We propose therefore this procedure as a new very convenient general method to obtain precious and normally unavailable information on the cellulose degradation by‐products from naturally aged paper.     

New Cyclosiloxanolate Cluster Complexes of Transition Metals

New cyclosiloxanolate transition metal cluster complex derivatives were prepared. PhSiO₂K reacted with NiX₂ (X₂ = Cl₂ or acac) to give K₂{[η⁶−(PhSiO₂)₆]₂[μ₃−(OH)]₂Ni₄K₄}, a mixed group 1–group 10 metal complex. PhSiO₂Na reacted with Ni(NH₃)₆I₂ to give Na{[η⁶−(PhSiO₂)₆]₂Ni₆(μ₆−I)} as the first example of “encapsulated” I⁻ ion in siloxanolate complexes. The macrocyclic Na₄{[η¹²−(PhSiO₂)₁₂]Cu₄} complex reacted with η⁶−(1,3,5−C₇H₈)Cr(CO)₃ to give the heterobimetallic adduct Na₄{[η¹²−(PhSiO₂)₁₂]Cu₄}· [Cr(CO)₃]₃ as one of the rare examples of heterobimetallic complexes with different oxidation numbers of the metals. The copper derivative {[η⁶−(PhSiO₂)₆]₂Cu₆(n−BuOH)₅} reacted in MeOH/CHCl₃ (1:6) with Et₄NCN to give the hexanuclear complex {[η⁶−(PhSiO₂)₆]₂Cu₆(η²−C₃H₅N₂O₂)₂}, containing 2-amino-2-oxoetanimidic acid methyl ester monoanion ligands, product of an unexpected C–C coupling reaction. This latter complex was characterized also by X-ray diffraction crystal and molecular structure determination. This paper is dedicated to the 70th birthday of Professor Dr. Gunter Schmid (Essen), pioneer of large cluster chemistry, known to friends as GOLD-Schmid, because of his famous discovery of the Au₅₅ cluster. The Authors are proud to be within his many friends.     

A general protocol for the regio high yielding opening of different glycidol derivatives

Differently protected glycidol derivatives (with Bn, TBDPS, TBS and MPM groups) have been tested for regioselective ring opening with vinylmagnesium bromide in order to obtain useful five-carbon functionalised homoallylic alcohols. Careful choice of the reagents and experimental conditions allowed a general access to important chiral synthons for asymmetric synthesis.     

Chemical and biological profiles of novel copper(II) complexes containing S-donor ligands for the treatment of cancer

In the last years, we have synthesized some new platinum(II), palladium(II), gold(I/III) complexes with dithiocarbamato derivatives as potential anticancer drugs, to obtain compounds with superior chemotherapeutic index in terms of increased bioavailability, higher cytotoxicity, and lower side effects than cisplatin. On the basis of the obtained encouraging results, we have been studying the interaction of CuCl2 with methyl-/ethyl-/tert-butylsarcosine-dithiocarbamato moieties in a 1:2 molar ratio; we also synthesized and studied the N,N-dimethyl- and pyrrolidine-dithiocarbamato copper complexes for comparison purposes. The reported compounds have been successfully isolated, purified, and fully characterized by means of several spectroscopic techniques. Moreover, the electrochemical properties of the designed compounds have been studied through cyclic voltammetry. In addition, the behavior in solution was followed by means of UV-vis technique to check the stability with time in physiological conditions. To evaluate their in vitro cytotoxic properties, preliminary biological assays (MTT test) have been carried out on a panel of human tumor cell lines. The results show that cytotoxicity levels of all of the tested complexes are comparable or even greater than that of the reference drug (cisplatin).     

Solvent-free synthesis of glycosyl chlorides based on the triphenyl phosphine/hexachloroacetone system

Glycosyl chlorides, useful as glycosyl donors in glycoside synthesis and precursors in organic synthesis, can be easily prepared under solvent-free conditions by exposing a sugar hemiacetal to an equimolar mixture of PPh₃ and hexachloroacetone at 70 °C. The reaction affords products in high yields and short times, and is tolerant of a wide range of commonly adopted protecting groups.     

Efficient plasmid DNA cleavage by a mononuclear copper(II) complex

The Cu(II) complex of the ligand all-cis-2,4,6-triamino-1,3,5-trihydroxycyclohexane (TACI) is a very efficient catalyst of the cleavage of plasmid DNA in the absence of any added cofactor. The maximum rate of degradation of the supercoiled plasmid DNA form, obtained at pH 8.1 and 37 degrees C, in the presence of 48 microM TACI.Cu(II), is 2.3 x 10(-3) s(-1), corresponding to a half-life time of only 5 min for the cleavage of form I (supercoiled) to form II (relaxed circular). The dependence of the rate of plasmid DNA cleavage from the TACI.Cu(II) complex concentration follows an unusual and very narrow bell-like profile, which suggests an high DNA affinity of the complexes but also a great tendency to form unreactive dimers. The reactivity of the TACI.Cu(II) complexes is not affected by the presence of several scavengers for reactive oxygen species or when measured under anaerobic conditions. Moreover, no degradation of the radical reporter Rhodamine B is observed in the presence of such complexes. These results are consistent with the operation of a prevailing hydrolytic pathway under the normal conditions used, although the failure to obtain enzymatic religation of the linearized DNA does not allow one to rule out the occurrence of a nonhydrolytic oxygen-independent cleavage. A concurrent oxidative mechanism becomes competitive upon addition of reductants or in the presence of high levels of molecular oxygen: under such conditions, in fact, a remarkable increase in the rate of DNA cleavage is observed.     

Effect of Kr ion irradiation on the Fe/SiO2 interface

Conversion electron Mössbauer spectroscopy (CEMS) has been used to investigate the various Fe coordination states at the interface of the Fe/SiO₂ couple after irradiation with 200 keV Kr ions in the dose range from 2.5×10¹⁵ to 3.5×10¹⁶ ions/cm². After removal of the unmixed Fe layer by a simple etching procedure, it was possible to recognize the presence of small Fe clusters, Fe-oxide and Fe-silicate phases, whose relative amount has been determined as a function of the irradiation dose. The amount of mixed Fe has been evaluated in the etched samples by means of Rutherford backscattering spectrometry (RBS). Structural changes in the interfacial region after thermal annealings for 5 h at 500 and 700°C have been detected and correlated to corre-sponding changes in optical properties.