207 research outputs found
Y-shaped alkynylimidazoles as effective push-pull fluorescent dyes for luminescent solar concentrators (LSCs)
Get PDFThe synthesis of three 2-arylalkynyl-4,5-diarylimidazoles endcapped with typical electron-donating (ED) and electron-withdrawing (EW) groups (push-pull system) and their evaluation as fluorescent dyes for thin-film luminescent solar concentrators (LSCs) is described. These novel Y-shaped imidazole-based fluorophores were easily assembled in good chemical yields through a three-step synthetic sequence involving a double Suzuki arylation, followed by a dehydrogenative alkynylation, and a Knoevenagel condensation. Their optical and spectroscopic properties were analyzed both in solution and in poly(methyl methacrylate) (PMMA) films. All the molecules in PMMA films showed an intense, red-shifted emission between 540 and 575 nm with large Stokes shift (>120 nm), moderate-to-good fluorescence quantum yields (QY) and good device efficiencies (ηdev), especially for compound 3
Computational Design, Synthesis, and Mechanochromic Properties of New Thiophene-Based pi-Conjugated Chromophores
No full textThe possibility of exploiting supramolecular architectures for the preparation of innovative mechano- chromic devices has been extended by designing novel thienyl-substituted 1,4- bis-(ethynyl)benzene dyes, which are characterized by a conjugated, rigid, rodlike core structure. This new family of chromophores was synthesized ac- cording to a simple two-step sequential cross-coupling reaction, and the optical properties were investigated in solution and in a polymeric matrix. To tune the mechanochromic performances in smart polymer materials, a virtual screening was set up that was able to select a derivative with optimal spectral features. The effective combination of experimental and computational inves- tigations allowed us to spot those ho- mologues with already potential aniso- tropic and aggregachromic features and characterized by the best spectral prop- erties and luminescent response. The best candidate was synthesized and dis- persed into a polyethylene matrix, indeed achieving an “in silico de- signed” mechanochromic material. Be- sides the specific applications of this novel material, the integration of com- putational and experimental techniques reported here defines an efficient pro- tocol that can be applied to make a se- lection among similar dye candidates, which constitute the essential respon- sive part of such supramolecular devices
CoolSun: organic paints for cool buildings
Get PDFPoor attention has been paid so far to the 50% of NIR radiation flux (750-2500 nm), coming from direct, diffused and reflected sun radiation, which contributes to increase the temperature in urban areas. To reduce the increasing demand for energy consumption for air conditioning or to produce cool fabrics, there is a need for NIR reflective pigments and coatings formulation since reflecting the sun’s radiation minimizes the amount of energy absorbed by the surface1. NIR reflective property is useful in applications where solar heating must be attenuated, such as leather goods, greenhouse coverings, roofing and transporting of heat-sensitive materials2 Today, NIR reflectivity is obtained with the use of inorganic pigments (TiO2, metal oxides and complexes) that are expensive and, in some cases, toxic2. The challenge is the development of a fully organic NIR reflective coating. This can be possible by mixing NIR non-absorbing pigments with polymeric NIR-reflective additives in the formulation of coatings.
This work aims at the preparation of paints starting from waterborne-dispersion of resin and NIR reflective organic pigments and additives. As pigment we used different perylene bis-imide derivatives, already known for their NIR reflective properties4. Aswell, we studied the synergic cool effect adding thermoplastic hollow microspheres (Expancel®)5 and their comparison with a standard black dye
Modeling, preparation and characterization of new fluorophores for smart polymer composite films
No full textPolymer composite films containing dyes of different structure characterized by optical responsiveness to external stimuli are studied because they are very promising for the development of smart and intelligent polymer devices for sensing and safety applications.
In this context, a computational work was carried out for the screening of UV-Vis absorption and emission spectra of a series of fluorophores containing functionalized thiophene rings with push-pull groups.
The theoretical most promising structures, based on new 1,4-bis-(thienylethynyl)benzene derivatives, were synthesized by a two-step sequence involving a Cassar-Heck coupling reaction followed by a Sila-Sonogashira reaction and and their main optical features were characterized in solution by UV-Vis and emission spectroscopies
A Morpho-Molecular Diagnosis of Papillary Thyroid Carcinoma: BRAF V600E Detection as an Important Tool in Preoperative Evaluation of Fine-Needle Aspirates
No full textBACKGROUND:
Although most thyroid nodule fine-needle aspiration (FNA) diagnoses are definitive or nearly definitive, about 30% of them are not read as definitively benign or malignant, the so-called indeterminate or suspicious FNA diagnosis. The prevalence of malignancy in FNA samples with these diagnoses varies from 10% to 52%. The first aim of this study was to determine if BRAF V600E analysis of thyroid FNA cytological smears could be performed with a relatively simple protocol. We also sought to determine if assessing the presence of BRAF gene mutations in preoperative FNA cytology slides would provide diagnostic information for FNA samples with a reading of indeterminate or suspicious thyroid lesions.
METHODS:
DNA was extracted directly from FNA-stained smears of 111 patients with thyroid lesions having different cytological diagnoses. There was 1 cystic nodule, 20 microfollicular proliferations without atypia, 32 that were suspicious for papillary carcinoma, 56 papillary thyroid carcinomas (PTC), and 2 poorly differentiated carcinomas. The BRAF V600E mutational status was determined by sequencing analysis in all patients. The histopathological diagnosis was obtained in all cases.
RESULTS:
We observed that 56/90 (62.3%) patients received a definitive diagnosis of PTC when only cytology was used. After molecular analysis, the BRAF V600E mutation was detected in 18/32 (56.2%) cases with a cytology of suspicious for papillary carcinoma and 41/56 (73.2%) with PTC. According to the morpho-molecular analysis (i.e., traditional cytology combined with BRAF V600E analysis) 74/90 (82.2%) patients could be assigned a definitive diagnosis of PTC. Therefore, the addition of molecular analysis yielded an increase of 20% in the sensitivity compared to cytology alone.
CONCLUSIONS:
The method of molecular analysis of thyroid FNA smears described here can be easily performed after the FNA, thereby avoiding inconvenience and additional time during the FNA and permitting later analysis of samples having indeterminate cytology features. The increased sensitivity of this preoperative morpho-molecular analysis should provide information that is useful in deciding the extent of thyroid surgery for thyroid nodules that are indeterminate or suspicious on cytology
Molecular profiling of microinvasive breast cancer microenvironment progression
Get PDFBackground: Tumors develop by progression through a series of stages. Every cell of the tumor microenvironment is constantly changing in the flow of the cancer progression. It has become clear in recent years that stroma is essential for tumor maintenance and growth. Here, we aimed to give a chronological order of gene expression changes given in the dynamical framework of microinvasive breast cancer microenvironment. Methods: RNA-seq was performed on seven microinvasive breast cancers. For each of them we microdissected seven different portions of the tumor, four related to the breast epithelium and three to the stroma. Breast epithelium was chronologically subdivided in normal breast epithelium (NBE), carcinoma in situ (CIS), emerging invasive fingers (EIF) and invasive breast cancer (IBC). For each of the breast epithelium subdivisions we collected the adjacent stroma (S): S-NBE, S-EIF and S-IBC. Results: The overall differentially expressed genes (DEGs) in all the compartments were analysed and evaluated to understand the pathways involved in tumor progression. Then we analysed the DEGs of the epithelial and stromal portions in comparison with the normal portions. We observed that the stromal cells are necessary for the development and the maintenance of the tumor, especially in tumor progression. Moreover the most important genes involved in the main metabolic pathways were analysed and the communications within the different cell compartments were highlighted. Conclusions: As a future perspective, a deeply study of the identified key genes, particularly in the stromal cells, will be crucial to develop an anticancer therapy that is undergoing a conversion from a cancer cell-centric strategy to a stroma-centric strategy, more genomically stable
Self-Assembled Amphiphilic Fluorinated Random Copolymers for the Encapsulation and Release of the Hydrophobic Combretastatin A-4 Drug
Get PDFWater-soluble amphiphilic random copolymers composed of tri(ethylene glycol) meth-acrylate (TEGMA) or poly(ethylene glycol) methyl ether methacrylate (PEGMA) and perfluoro-hexylethyl acrylate (FA) were synthesized by ARGET-ATRP, and their self-assembling and ther-moresponsive behavior in water was studied by dynamic light scattering (DLS) and UV-vis spec-troscopy. The copolymer ability to self-fold in single-chain nano-sized structures (unimer micelles) in aqueous solutions was exploited to encapsulate Combretastatin A-4 (CA-4), which is a very hy-drophobic anticancer drug. The cloud point temperature (Tcp) was found to linearly decrease with increasing drug concentration in the drug/copolymer system. Moreover, while CA-4 was preferen-tially incorporated into the unimer micelles of TEGMA-ran-FA, the drug was found to induce mul-ti-chain, submicro-sized aggregation of PEGMA-ran-FA. Anyway, the encapsulation efficiency was very high (≥81%) for both copolymers. The drug release was evaluated in PBS aqueous solutions both below and above Tcp for TEGMA-ran-FA copolymer and below Tcp, but at two different drug loadings, for PEGMA-ran-FA copolymer. In any case, the release kinetics presented similar profiles, characterized by linear trends up to ≈10–13 h and ≈7 h for TEGMA-ran-FA and PEGMA-ran-FA, respectively. Then, the release rate decreased, reaching a plateau. The release from TEG-MA-ran-FA was moderately faster above Tcp than below Tcp, suggesting that copolymer ther-moresponsiveness increased the release rate, which occurred anyway by diffusion below Tcp. Cy-totoxicity tests were carried out on copolymer solutions in a wide concentration range (5–60 mg/mL) at 37 °C by using Balb/3T3 clone A31 cells. Interestingly, it was found that the concentra-tion-dependent micro-sized aggregation of the amphiphilic random copolymers above Tcp caused a sort of “cellular asphyxiation” with a loss of cell viability clearly visible for TEGMA-ran-FA solutions (Tcp below 37 °C) with higher copolymer concentrations. On the other hand, cells in contact with the analogous PEGMA-ran-FA (Tcp above 37 °C) presented a very good viability (≥75%) with respect to the control at any given concentration
Allergeni indoor: non solo acari.
No full textSummary: The indoor environment is a source of airway risk factors. The main agents related to exacerbation and development of rhinoconjunctivitis and asthma are house dust mites, pet’s epithelia, moulds, environmental tobacco smoke, and outdoor and indoor chemical pollutants. This paper reports the relationship between the outdoor and indoor concentrations of pollen and mould spores
COOLSUN: a preliminary study of “cool” properties of organic pigments
Get PDFApproximately 50% of the solar energy reaching the earth is emitted in the near infrared region (NIR), not detectable by human eye. The absorption by an object in the NIR causes an increase of its temperature1.
The pigments that interact with the NIR portion of the solar spectrum (i.e. between 700 and 1600 nm) without absorbing it are called NIR-reflecting, and their use reduces the heating of the treated substrates2. The NIR-reflective property is useful in applications where solar heating must be attenuated, such as leather goods, greenhouse coverings ,roofing and transporting of heat-sensitive materials3. Today, NIR reflectivity is obtained with the use of inorganic pigments (TiO2, metal oxides and complexes) that are expensive and, in some cases, toxic1. The key to obtain innovative coatings is then the production of organic NIR-reflective pigments to overcome problems related to costs, environmental impact, efficiency and color index of the current inorganic pigments on the market4. The goal of our work is the development of innovative products containing organic-based NIR reflective and/or NIR transparent pigments. In this preliminary phase of our project we focused on the study of the "cool" properties of commercial pigments in order to be able to design and develop thermo- and photostable organic pigments, able to reflect the radiation in the NIR. The pigments were initially dispersed in a polymeric matrix, the produced mixture was applied on white (maximum reflectance) and black (maximum absorption) test panels. The percentage reflectance of two test panels (black and white) for each pigment was determined using a UV-Vis-NIR spectrophotometer. The pigment/matrix mixtures were then applied on leather samples for the determination of the cool properties through the use of a thermal imaging camera
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