Optical gap energy study of poly(thienylene-2,5-dialkoxyphenylene) in solid-state films.

Optical gap energy (Egap) in luminescent π-conjugated polymers presents several difficulties in its determination, particularly when using CW conventional optical spectroscopy, absorption and emission. This happens due to several physicochemical parameter's dependence. Among others, the molecular conformation, intramolecular interactions, structural defects, polymer processability and solvent interaction stand out. In addition, there is a distribution of conjugated segments along the polymeric main chains that differentiate optical absorption transition from emission processes. In other words, these processes do not necessarily occur in the same conjugated segment owing to the very efficient ratios of energy transfer or charge migration in these materials. In this work we present a systematic study of the determination of Egap for the polymer poly(thienylene-2,5-dialkoxyphenylene). We present a comparison between the solution and solid-state film, clearly showing the presence of a polymer-polymer interaction as aggregate species. The goal of this paper is to isolate and aggregate the contribution determination of each species through systematic analysis of optical spectra, as well as to obtain, even on film, the Egap of the isolated polymer which is very similar to the polymer solution at about 2.37 eV. The intersection theory and the voltammetry methods corroborate the experiment and the discussion of the results obtained.

Influence of Different Cordless Light-emitting-diode Units and Battery Levels on Chemical, Mechanical, and Physical Properties of Composite Resin.

CLINICAL RELEVANCE: Irradiance may decrease as the light-emitting diode (LED) is discharged. Therefore, the LED must be charged carefully to prevent the possibility of influencing the chemical, mechanical, and physical properties of composite resin. SUMMARY: The aim of this study was to evaluate the influence of different light-emitting diode (LED) curing units and battery levels on the chemical, mechanical, and physical properties of composite resins. The irradiance for each cycle from full to completely discharged battery level was evaluated, for five different new cordless LED units: Optilight Color (Gnatus), Bluephase (Ivoclar), Valo (Ultradent), Radii Plus (SDI), and Radii Xpert (SDI). After the irradiance evaluation, composite resin specimens were prepared and light cured, while varying the battery level for each LED unit: high level (HL, 100%), medium level (ML, 50%), and low level (LL, 10%). The degree of conversion, diametral tensile strength, sorption, and solubility were also evaluated. Data were checked for homoscedasticity and submitted to two-way and three-way analysis of variance, depending on the test performed, followed by the Tukey test with a significance level of 95%. A negative correlation was found between irradiance and cycles of light curing, which was checked by the Pearson correlation test. Valo and Radii Xpert were not influenced by the battery level in any test performed. However, different battery levels for some LED units can influence the degree of conversion, diametral tensile strength, sorption, and solubility of composite resins.

A new designed π conjugated molecule for stable single walled carbon nanotube dispersion in aqueous medium.

A molecule with a π conjugated backbone built from aromatic thiophene and dialkoxyphenylene units and substituted imidazolium groups (TPO) is designed to obtain ultra-stable single walled carbon nanotube (SWCNT) dispersion in aqueous medium. The proposed mechanism of non-covalent interaction is accompanied by individualization of SWCNT and comprises of dominant nondisruptive π-π and cation-π interaction between them and the TPO conjugated oligomer. The individualization of SWCNT and dispersibility and stability of the ultra-stable suspensions were estimated using high resolution transmission electron microscopy, UV-Visible-NIR absorption spectroscopy, Raman spectroscopy, photoluminescence and zeta potential measurement. Nuclear magnetic resonance data provides direct evidence toward possible cation-π interaction.

Morphostructural analysis of the male reproductive system and DNA barcoding in Balclutha brevis Lindberg 1954 (Homoptera, Cicadellidae).

Balclutha brevis Lindberg 1954 is an allochthonous leafhopper infesting an invasive grass, Pennisetum setaceum, in Sicily and in mainland Europe; therefore, this species could compete with populations of native species, thus contributing to the loss of biodiversity. Considering the ecological implications of B. brevis, investigations on all its biological aspects represent, therefore, a premise for further studies in applied sciences. Based on the lacking ultrastructural data about the reproductive systems of the Auchenorrhyncha, we carried out morphostructural investigations on the male reproductive system of B. brevis. Further, a first report of DNA barcoding analysis (amplification and sequencing of Cytochrome Oxidase I gene) has also been performed to characterize B. brevis compared to other congeneric species. From a morphological point of view, the male reproductive system of B. brevis has an organization comparable to the general anatomical features of most of the Auchenorrhyncha species; however, comparing our data with those concerning the different groups of Cicadomorpha, some considerations are discussed. As for the histological and ultrastructural investigations, our results show a secretory activity of the various examined structures, mainly in the lateral ejaculatory ducts and in the accessory glands. The latter, in particular, show morphostructural differences comparing the distal tract to the proximal one; moreover, the histochemical techniques showed the possible presence of a lipid component in the peculiar cytoplasmic granules found in the gland cells. The significance of these findings in the accessory glands is discussed. Finally, the ultrastructural features found in the seminal vesicles are different from those of the lateral ejaculatory ducts and are indicative of the different roles played by these structures in the organization of the spermatozoa bundles.

Investigation of ground- and excited-state photophysical properties of 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin with ruthenium outlying complexes.

The present work employs a set of complementary techniques to investigate the influence of outlying Ru(II) groups on the ground- and excited-state photophysical properties of free-base tetrapyridyl porphyrin (H(2)TPyP). Single pulse and pulse train Z-scan techniques used in association with laser flash photolysis, absorbance and fluorescence spectroscopy, and fluorescence decay measurements, allowed us to conclude that the presence of outlying Ru(II) groups causes significant changes on both electronic structure and vibrational properties of porphyrin. Such modifications take place mainly due to the activation of nonradiative decay channels responsible for the emission quenching, as well as by favoring some vibrational modes in the light absorption process. It is also observed that, differently from what happens when the Ru(II) is placed at the center of the macrocycle, the peripheral groups cause an increase of the intersystem crossing processes, probably due to the structural distortion of the ring that implies a worse spin-orbit coupling, responsible for the intersystem crossing mechanism.

Linear and nonlinear optical properties of the thiophene/phenylene-based oligomer and polymer.

In this article, we investigate the linear and nonlinear optical properties of the thiophene/phenylene-based oligomer (SL128G) and polymer (FSE59) chemically modified with alquilic chains, which allow greater solubility and provide new optical properties. These compounds present a strong absorption in the UV-visible region, providing a wide transparence window in visible-IR, ideal for applications in nonlinear optics. Employing the Z-scan technique with femtosecond pulses, we show that these compounds exhibit considerable two-photon absorption (2PA), with two 2PA allowed states located at 650 and 800 nm for SL128G and 780 and 920 nm for FSE59. Moreover, we observe the resonance enhancement effect as the excitation wavelength approaches the lowest one-photon-allowed state. By modeling the 2PA spectra considering a four-energy-level diagram within of the sum-over-essential states approach, we obtained the spectroscopic parameters of the electronic transitions to low-energy singlet excited states. Additionally, photoluminescence excited by femtosecond and picosecond pulses were performed to confirm the order of the multiphoton process and estimate the fluorescence lifetime, respectively.

Controlling bandgap energy and multivibronic modes of a poly(2,5-thiophene-1,4-dialkoxyphenylene) derivative by gamma photons.

In this work, the influence of γ radiation on electronic, structural, and vibrational properties of a poly(2,5-thiophene-1,4-dialkoxyphenylene) derivative is studied by optical absorption and photoluminescence. A Gaussian fit of emission spectra within Franck-Condon vertical transitions formalism was carried out in order to understand how vibronic coupling is affected by the dose, because an unexpected luminescence behavior was observed. Aiming to understand the ionizing radiation-matter interaction processes, we employed a molecular modeling procedure, through the use of a semiempirical method (AM1) applied to conjugated oligomers' conformational structure and equilibrium geometries, to clarify the defects induction for the used doses. From AM1 optimized structures, electronic transitions were calculated by ZINDO/S-CI semiempirical method to measure the chain scission degree. Moreover, with the results presented in this work, it is possible to come up with a new physical-chemical route to treat and increase conjugated polymers' efficiency. Finally, we believe that the present paper contributes to the literature about defects on conjugated polymers.

Daily tonometric curves after cataract surgery.

AIM: To evaluate daily tonometric curves after cataract surgery in patients with cataract only and in patients with cataract and glaucoma. METHODS: 108 patients scheduled for cataract surgery were randomly allocated to two groups: 57 patients with cataract only (normal) and 51 with cataract and primary open angle glaucoma (POAG). All patients underwent extracapsular cataract extraction (ECCE) (manual technique with long wound), phacoemulsification (automated technique with short wound), or nucleus capture (manual technique with short wound). Intraocular pressure (IOP) was measured by Goldmann tonometry in all patients every 2 hours for 12 hours before the operation and at 1 and 6 months postoperatively. RESULTS: 79 patients completed the 6 month examination. ECCE resulted in greater reductions in IOP than the other procedures (ECCE: 27% and 36% in normal patients and those with POAG, respectively; nucleus capture: 20% and 31%, respectively; phacoemulsification: 19% and 22%, respectively). The fluctuations in IOP before and after surgery were not statistically significant. CONCLUSION: Cataract surgery in normal patients reduces IOP but does not eliminate fluctuations which are directly proportional to the IOP value and result partly from circadian rhythms. This important finding might influence our approach to treatment of patients with glaucoma.

[Epidemiological study of Chlamydia trachomatis infection in a sample of women requesting voluntary termination of pregnancy, treated with rokitamycin]. / Studio epidemiologico sull'infezione da Chlamydia trachomatis in un campione di donne che richiedono l'IVG trattate con rokitamicina.

BACKGROUND: Infection with Chlamydia trachomatis usually involves the cervix uteri, causing no symptoms, and may easily be unrecognised and untreated until troublesome symptoms arise, such as pelvic inflammatory disease, which can affect fertility and reproductive life. Therapies include the macrolide antibiotics, and in this class rokitamycin offers marked lipophilia, excellent intracellular penetration, and bactericidal activity at concentrations close to the MIC. The present study was therefore designed to establish the frequency of intracervical infection with Chlamydia trachomatis in women applying for termination of pregnancy, and to assess the efficacy and safety of this drug in this indication. METHODS: Women aged 18-40 years were admitted for termination of pregnancy, with a positive cervical swab for Chlamydia trachomatis. The study was conducted in accordance with the Declaration of Helsinki and amendments. Patients were given one oral tablet of 400 mg rokitamycin in the morning, and one in the evening, for two weeks. Treatment started ten days before the termination, within 48 h of taking the swab. Partners were to receive the same treatment. RESULTS: 292 women requiring termination of pregnancy, on average at the 9th week of pregnancy, were assessed. Of these, 24 (8.2%), mean (+/- SD) age 27.1 +/- 6.1 years, range 18-39, with a positive cervical swab for Chlamydia trachomatis, were treated with rokitamycin; 22 of their partners were treated too. Forty days after the start of treatment 22 patients (92%) gave negative results; these were all the cases whose partners had received treatment. No adverse events were reported and the acceptability of the treatment was considered good or excellent in 91% and fair in 9% of the cases. CONCLUSIONS: The findings confirm that rokitamycin is one of the most useful and effective macrolides for the treatment of infections caused by intracellular microorganisms; it is extremely well tolerated and has marked microbiological efficacy.

[Peritoneal cystic mesothelioma]. / Mesotelioma cistico del peritoneo.

Cystic mesothelioma of peritoneum is a rare neoplasia that was identified as a individual entity by ultrastructural and immunoistochemical studies. It is more frequent in young woman and often it tends to recur. Because of its rarity and difficulty in differential diagnosis, the Authors describe a case of cystic mesothelioma observed.

Fluctuations of intraocular pressure during the day in open-angle glaucoma, normal-tension glaucoma and normal subjects.

PURPOSE: The aim of the present paper is to describe the variations in intraocular pressure (IOP) during the day in normals, in patients with primary open-angle glaucoma (POAG) and in patients with normal-tension glaucoma (NTG). IOP represents one of the most important risk factors for glaucoma. However the IOP value is not constant during the day and IOP fluctuation could influence the diagnostic and prognostic evaluation of the glaucomatous disease. METHODS: For this purpose IOP was evaluated every 2 h from 8 a.m. to 8 p.m. in one randomized eye of 33 normal subjects, 95 POAG and 50 NTG patients. RESULTS: The results show that the highest IOP values were detectable in the morning in all three groups. The lowest values were found in the early afternoon hours. These variations were most evident in POAG patients. The daily IOP fluctuations were directly proportional to IOP level. CONCLUSION: The study evidents that a single tonometric evaluation, especially if done in the first hours of the afternoon, is not sufficient to correctly evaluate the IOP-related risk in glaucoma patients. If the pressure peaks are important in determining the extent of glaucomatous damage in NTG patients IOP should not have an important role in optic nerve head damage. The use of diurnal curves seems to be mandatory for the assessment of IOP-related risk and of efficiency of the therapeutic approach.

Fatty acid composition of human milk in Italy.

The fatty acid composition of breast milk from 20 Italian women, delivering at term and on ad libitum diets, was analyzed with high-resolution gas chromatography. Milk samples were collected twice a day, on the 1st, 4th, 7th, 14th, 21st and 28th day after colostrum appearance. No significant differences were detected between the two daily samples. During the maturation process a significant reduction in long-chain polyunsaturated fatty acids of the n-6 series (p = 0.002) and n-3 series (p = 0.005) was recorded, particularly in arachidonic acid (p = 0.035), docosatetraenoic acid (p = 0.035) and docosahexaenoic acid (p = 0.032). The linoleic acid/n-6 and alpha-linolenic acid/n-3 ratios increased (p = 0.024 and p = 0.037), while the docosatetraenoic/docosahexaenoic acid ratio decreased (p = 0.032). The fatty acid composition of mature milk was the following: saturated 45.50%; unsaturated 54.51%; monounsaturated 42.69%; polyunsaturated 11.82%; long-chain polyunsaturated 1.27%; linoleic acid 9.79%, and alpha-linolenic acid 0.36%. The fatty acid composition of milk collected from Italian women appears similar to that of women in other southern European countries and, therefore, could reflect dietary habits.

[Postcoital contraception. Dates based on a 5-year use in a private consultation service]. / Intercezione post-coitale. Dati relativi a cinque anni di utilizzo in un consultorio privato.

BACKGROUND: The aim of this 5-year retrospective study is to define the efficacy of oestro-progestinic interception. METHODS: An oestro-progestinic mixture (0.05 mg ethinyl estradiol and 0.250 mg dlnorgestrel) was prescribed to 6003 women attending the gynaecological outpatients clinic of AIED (Associazione Italiana per l'Educazione Demografica) in Genoa, Italy, without evidence of any previous contra-indications. The prescription was of two pills at once and two pills 12 hours after. Before examination, the doctor asked for personal and medical history (age, date of onset of menses, unprotected intercourse date and anticonceptional failure); patients were also asked to report the data of the following menses to the clinic. The largest age range was between 20 and 24 years, probably because of their inadequate knowledge of contraceptives. The reasons for post-coital contraception were: sexual intercourse without contraceptive, failure of coitus interruptus and of the condom. RESULTS: Post-coital interception efficacy (monthly oestro-progestinic contraception was 99.5%) according to retrospective statistical analysis, was according to Pearl index 92.9% vs 50% without any contraceptive. CONCLUSIONS: Finally, the efficacy of this method, together with its easy management and low frequency of severe contra-indications, allows us to indicate the "morning after pill" as one of the most useful outpatient strategies to avoid unwanted pregnancies.

Simultaneous measurement of gastric emptying of digestible and indigestible solids in healthy humans.

Gastric emptying of digestible and indigestible solids has been simultaneously evaluated in healthy humans. Gastric emptying of indigestible solids occurs simultaneously during the emptying of digestible solids. The knowledge of the mechanism responsible for gastric emptying of both digestible and indigestible solids may contribute to improve physiologic insight in this field and to develop further clinical applications.

Comparison between gastric emptying of digestible and indigestible solids in diabetic patients.

We measured simultaneously gastric emptying of digestible and indigestible solids in 10 normal subjects and in 14 insulin-requiring diabetic patients. Our results demonstrate that in both diabetics and in controls the gastric emptying of digestible and indigestible solids occurs during the same phase of gastric motor activity, i.e. during the post-prandial period. However, gastric emptying of both digestible and indigestible solids is delayed in diabetic patients compared to controls.