Monolayers and multilayers of conjugated polymers as nanosized electronic components

Conjugated polymers (CPs) are interesting materials for preparing devices based on nanoscopic molecular architectures because they exhibit electrical, electronic, magnetic, and optical properties similar to those of metals or semiconductors while maintaining the flexibility and ease of processing of polymers. The production of well-defined mono- and multilayers of CPs on electrodes with nanometer-scale, one-dimensional resolution remains, however, an important challenge. In this Account, we describe the preparation and conductive properties of nanometer-sized CP molecular structures formed on electrode surfaces--namely, self-assembled monolayer (SAM), brush-type, and self-assembled multilayer CPs--and in combination with gold nanoparticles (AuNPs). We have electrochemically polymerized SAMs of carboxyalkyl-functionalized terthiophenes aligned either perpendicular or parallel to the electrode surface. Anodic coupling of various pyrrole- and thiophene-based monomers in solution with the oligothiophene-based SAMs produced brush-like films. Microcontact printing of these SAMs produced patterns that, after heterocoupling, exhibited large height enhancements, as measured using atomic force microscopy (AFM). We have employed layer-by-layer self-assembly of water-soluble polythiophene-based polyelectrolytes to form self-assembled multilayers. The combination of isostructural polycationic and polyanionic polythiophenes produced layers of chains aligned parallel to the substrate plane. These stable, robust, and dense layers formed with high regularity on the preformed monolayers, with minimal interchain penetration. Infrared reflection/adsorption spectroscopy and X-ray diffraction analyses revealed unprecedented degrees of order. Deposition of soluble polypyrroles produced molecular layers that, when analyzed using a gold-coated AFM tip, formed gold-polymer-gold junctions that were either ohmic or rectifying, depending of the layer sequence. We also describe the electronic conduction of model alpha,omega-capped sexithiophenes featuring a range of electron donor/acceptor units and lengths of additional conjugation. The sexithiophene cores exhibit redox-type conductivity, developing at the neutral/cation and cation/dication levels with values depending the nature of the substitution and the redox system. Extending the conjugation beyond the sexithiophene frame introduces further oxidation processes displaying enhanced conductivity. Finally, we discuss the ability of CP-based monolayers to coordinate AuNPs. Although thiophene- and pyrrole-based oligomers aggregate toluene-soluble AuNPs, alkyl substitution inhibits the aggregation process through steric restraint. Consequently, we investigated the interactions between AuNPs and polypyrrole or polythiophene monolayers, including those formed from star-shaped molecules. The hindered aggregation provided by alkyl substituents allowed us to adsorb thiol-functionalized oligothiophenes and oligopyrroles directly onto preformed AuNPs. Novel materials incorporating AuNPs of the same size but bearing different conjugated ends or bridges have great promise for applications in electrocatalysis, electroanalysis, and organic electronics.     

Simultaneous Determination of Squalene, α-Tocopherol and β-Carotene in Table Olives by Solid Phase Extraction and High-Performance Liquid Chromatography with Diode Array Detection

Olives, the fruit of the Olea europaea tree, are highly appreciated in olive oil and table olives (20 % of crops) not only for their flavor but also for their nutritional properties, especially for antioxidant compounds such as squalling (SQ), α-tocopherol (TH) and β-carotene (BC). This paper presents a new analytical method for simultaneously determining SQ, TH and BC in table olives by using solid phase extraction (SPE) and high performance-liquid chromatography with diode array detection (HPLC-DAD), avoiding the classic saponification process. The correlation coefficients of calibration curves of the analyzed compounds ranged from 0.998 to 0.999, and the recoveries were in the range of 89.4–99.6 %. The validated method was used to analyze 30 table olive samples from Italy for their content of SQ (537–1,583 mg kg^?1), TH (21–90 mg kg^?1) and BC (0.4–2.6 mg kg^?1). Finally, experiments with HPLC-MS were conducted to compare this novel method with the classic saponification procedure.     

Optimization of espresso machine parameters through the analysis of coffee odorants by HS-SPME-GC/MS

The aroma profile and the final quality of espresso coffee (EC) are influenced by such technical conditions as the EC machine extraction temperature and the pressure used. The effect of these two parameters on EC quality were studied in combination by headspace solid phase micro extraction-gas chromatography-mass spectrometry (SPME-GC-MS) and sensory profile. Moreover, 10 key odorants at the best EC machine settings were examined to compare the two coffee cultivars (Arabica and Robusta) and two EC machines [Aurelia Competizione (A) and Leva Arduino (B)]. The data obtained provides important information about espresso making technique, suggesting that the usual espresso machine temperature and pressure settings (i.e. 92°C and 9bar) are very close to those needed to obtain the best quality espresso. This confirms the traditional wisdom of coffee making, which judges 25ml, the typical volume of a certified Italian EC, to be ideal for very strong aroma intensity.     

Chemical fingerprinting and bioactivity of Amazonian Ecuador Croton lechleri Müll. Arg. (Euphorbiaceae) stem bark essential oil: A new functional food ingredient?

Croton lechleri essential oil has been obtained by steam distillation of fresh stem bark from Amazonian Ecuador adult plants (yield: 0.61 ml/kg [0.061%]; density: 1.01 g/ml), and then chemically characterised by GC (Gas Chromatography) and GC–MS (gas chromatography–mass spectrometry). Seventy-four chemicals were detected and identified; the most abundant in descending order, were the sesquiterpenes sesquicineole (17.29%), α-calacorene (11.29%), 1,10-di-epi-cubenol (4.75%), β-calacorene (4.34%) and epi-cedrol (4.09%). Monoterpenes checked with a relative peak area higher than 2.0% were α-pinene (2.01%), p-cymene (2.61%), limonene (4.20%) and borneol (2.67%). The structure of the main chemicals were confirmed by GC–MS and ¹H NMR analyses. Spectrophotometric 1,1-diphenyl-2-picrylhydrazyl (DPPH) and DPPH-(high performance) thin layer chromatography (DPPH-(HP)TLC) bioautographic assays showed a lower radical scavenging capacity (IC₅₀) with respect to commercial thyme essential oil and BHA (butylated hydroxyl anisole), pointing out, however, that the C. lechleri essential oil fraction, characterised by α-calacorene, β-calacorene and δ-cadalene, was the most involved in the bioactivity. Similar results were obtained with β-carotene bleaching assay, where the IC₅₀ values were 0.291 ± 0.024 mg/ml for C. lechleri essential oil, 0.164 ± 0.013 and 1.34 × 10⁻⁴ ± 10⁻⁵ mg/ml for thyme essential oil and BHA, respectively. (HP)TLC-bioautographic assay performed with Gram positive and Gram negative bacteria revealed a minimum inhibitory concentration (MIC) values comprised between 0.10 mg/ml (Escherichia coli) and 10.10 mg/ml (for e.g. Pseudomonas aeruginosa), and the fraction mainly characterised by sesquicineole (97.38%) as the most involved in antibacterial capacity. Ames test employing Salmonella typhimurium TA98 and TA100 with and without a metabolic activation mixture (S9 mix) demonstrated the absence of mutagenicity of the C. lechleri essential oil between a concentration range of 10⁻² and 100 mg/plate. The same results were achieved by Saccharomyces cerevisiae D7 strain assay. An interesting mutagen-protective efficacy was evidenced by a 30% and 33% revertants reduction of TA98 strain treated with 2-aminoanthracene and nitrofluorene (2 μg/plate), suggesting, above all, the possibility to employ C. lechleri essential oil as a new flavouring protective ingredient for foods or dietary supplements against potential mutagens formed during cooking and/or processing in general.     

Development of an ELISA Reverse-Based Assay to Assess the Presence of Mycotoxins in Cereal Flour

The first successful application of the ELISA reverse method and device (ER m&d), in the context of food safety and traceability, was developed in our laboratories to detect and quantify CP4EPSPS and Cry1AB genetically modified related proteins in soy and maize samples, respectively. To prove the versatility and the transferability of the technology, the ER was here applied to assess the presence of mycotoxins in cereals. Appropriate protocols were developed to assess the presence of deoxynivalenol and ochratoxin A and the ER was tested on contaminated wheat samples. In particular, deoxynivalenol (DON) and ochratoxin A (OTA) were detected in a range of values from 430 to 5,000 μg kg⁻¹ and from 1.7 to 10 μg kg⁻¹, respectively. The assays were optimized to reach a limit of quantification equal to 550 and 1.8 μg kg⁻¹ for DON and OTA, respectively.     

Large airplane crash on a nuclear plant: Design study against excessive shaking of components

The problem of the strong shaking of structures and of components in case of an aircraft impact is the subject of this study. This problem is solved in some designs by protecting the external Nuclear Island block (N.I.) by an external thick wall, capable to withstand the aircraft impact. This wall is connected to the rest of the N.I. by the common foundation slab only. The first part of this study consists of the evaluation of the order of magnitude of the vibration attenuation which can be obtained by this design scheme. Should the attenuation obtained be not sufficient for some parts of the internal structures, some additional design provision could be adopted. In order to solve this problem, a specific design solution is here suggested. It essentially consists in connecting critical parts of structures to the common foundation slab with restraints having an adequate degree of deformability, so that the transmission of high frequency impact forces from other parts of the whole structure is minimized. In a previous paper (Petrangeli, 2007), the structural protection of the reactor dome and of connected structures of a modern nuclear plant is dealt with. In the present paper, the protection of internal parts of the plant (the internal containment is chosen) in case of strong impact on lateral walls is studied. The indicative result of this study is that the enhancement of attenuation in the transmission of acceleration from the impact point to some representative point in the inner structure is of the order of 75. This result cannot be generalized, as it depends on many parameters of the structure and of the soil.     

The occurrence of ochratoxin A in blue cheese

Evidence for the occurrence of ochratoxin A in blue cheeses is reported for the first time. The development of an accurate and reliable procedure for the extraction of OTA from cheese, as well as the availability of a new sensitive HPLC-FLD method, has allowed us to determine ochratoxin A in complex matrices such as cheeses, even at very low levels (LOD in cheese: 0.02 μg/kg). A good linearity for the OTA concentration, between 0.2 and 2.5 μg/kg, was obtained and no matrix effect was observed in the same concentration range. The mean recovery for OTA was 97%, while the average RSD was 3%, within a spiking range of 0.5–2.0 μg/kg.     

Role of Oxidative Stress in Peyronie’s Disease: Biochemical Evidence and Experiences of Treatment with Antioxidants

Background: Peyronie’s disease (PD) is a chronic inflammatory condition affecting adult males, involving the tunica albuginea of the corpora cavernosa of the penis. PD is frequently associated with penile pain, erectile dysfunction, and a secondary anxious–depressive state. The etiology of PD has not yet been completely elucidated, but local injury is generally recognized to be a triggering factor. It has also been widely proven that oxidative stress is an essential, decisive component in all inflammatory processes, whether acute or chronic. Current conservative medical treatment comprises oral substances, penile injections, and physical therapy. Aim: This article intends to show how antioxidant therapy is able to interfere with the pathogenetic mechanisms of the disease. Method: This article consists of a synthetic narrative review of the current scientific literature on antioxidant therapy for this disease. Results: The good results of the antioxidant treatment described above also prove that the doses used were adequate and the concentrations of the substances employed did not exceed the threshold at which they might have interacted negatively with the mechanisms of the redox regulation of tissue. Conclusions: We believe new, randomized, controlled studies are needed to confirm the efficacy of treatment with antioxidants. However, we consider the experiences of antioxidant treatment which can already be found in the literature useful for the clinical practice of urologists in the treatment of this chronic inflammatory disease.     

用于航空电子学应用的红外热摄像机

本文介绍了本公司已经研制成功的两台第二代热成像仪的设计,它们是分别用于NH90战术运输直升机(NH90 TTH)的导航前视红外仪和意大利ATR42海军巡逻飞机(ATR42 MPA)的电光监视与跟踪系统的.这两项计划的设计目标都是尺寸小、重量轻和功耗低.特别是,NH90-TTH热成像仪是一台工作于8 μm-12 μm波段的带单个宽视场(30°×40°)的紧凑型摄像机(6kg).为ATR42 MPA巡逻机研制的那台热成像仪具有一个特点,即它装有一个配备衍射光具的可遥控切换三种视场的物镜.介绍了这两台热成像仪的性能目标、创新性设计情况以及测试结果.