Plasmonic polyaniline/gold nanorods hybrid composites for selective NIR photodetection: Synthesis and characterization

Abstract In this study, we present the development of polyaniline/gold nanorod nanocomposites and the effect of the nanorods' aspect ratio and concentration on the overall electrical conductivity of nanocomposite systems. The electrical characterization showed that at the same atomic gold concentration, the conductivity of the nanocomposites increased by about 14% after increasing the gold nanorods' aspect ratio from 2.9 to 3.8. Furthermore, the conductivity of the nanocomposites increases linearly with the concentration of atomic gold, keeping the nanorods' aspect ratio stable, due to increasing the metallic content. The interaction between polyaniline and gold nanorods was investigated by FTIR, micro Raman, and XPS spectroscopic techniques, indicating the delocalization of the charges across the polymer chains induced by the incorporation of the nanorods. The interaction most likely occurs through the imine nitrogen of the polymer's backbone. The homogenous distribution of the gold nanorods in the polyaniline matrix was verified by TEM. Furthermore, the selective photosensitivity of the developed nanocomposites to NIR light was examined, and an increase in their current density was detected when the nanocomposites were irradiated at the wavelength that coincides with the longitudinal plasmonic resonance absorption of the incorporated nanorods. We foresee applications of the developed nanocomposites in numerous optoelectronic sectors

A new tool for the assessment of the development of students' mathematical competencies

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Mechanical reinforcement and water repellency induced to cellulose sheets by a polymer treatment

The present study reports a simple method to control the mechanical and surface properties of cellulose fiber networks and to protect them from humidity, without altering their initial morphology. This is achieved by dip coating the fiber networks in solutions containing different amounts of ethyl cyanoacrylate monomer (ECA). Under ambient humidity and due to the presence of the -OH groups of the cellulose, the ECA polymerizes around each individual cellulosic fiber forming a thin poly(ethyl cyanoacrylate) (PECA) shell. PECA was found to interact with the cellulose surface via hydrogen bonding as evidenced by Fourier transform infrared spectroscopy and thermogravimetric analysis measurements. The detailed surface characterization reveals that only 3.5 wt% of ECA in solution is sufficient to form compact PECA cladding around every cellulose fiber. After the proposed treatment the cellulose sheets become hydrophobic, well protected from the environmental humidity and with increased Young's modulus

Prognostic value of follicular fluid 25-OH vitamin D and glucose levels in the IVF outcome

Objectives: The aim of the present study was to measure serum and follicular fluid 25-OH vitamin D and glucose levels in women who underwent IVF-ET treatment and to further investigate whether the circulating 25-OH vitamin D and glucose levels correlate with IVF success. Methods: This prospective observational study included 101 consecutive women who underwent 101 IVF-ICSI ovarian stimulation cycles and were allocated to one of the three groups according to their follicular fluid 25-OH vitamin D concentrations. Group A (n = 31) with less than 20 ng/ml, group B (n = 49) with vitamin levels between 20.1 and 30 ng/ml and group C (n = 21) with more than 30 ng/ml vitamin concentration. Results: Follicular fluid vitamin levels significantly correlated with the quality of embryos in total (r = -0.27, p = 0.027), while the quality of embryos of group C were of lower quality as compared to those of groups A and B (p = 0.009). Follicular fluid glucose levels were lower in women of group C as compared to the respective levels of groups A and B (p = 0.003). Clinical pregnancy rate demonstrated in 14.5% in women of group C and 32.3% and 32.7% in groups A and B, respectively (p = 0.047). Conclusion: The data suggests that excess serum and follicular fluid vitamin levels in combination with decreased follicular fluid glucose levels have a detrimental impact on the IVF outcome

Lunar impact flash results and space surveillance activities at Kryoneri Observatory

We present current and future activities regarding lunar impact flash and NEO observations and satellite tracking from Kryoneri Observatory. In particular, we present results from the ESA-funded NELIOTA program, which has been monitoring the Moon for impact flashes since early 2017. Using the 1.2 m Kryoneri telescope, which is equipped with two high frame-rate cameras recording simultaneously in two optical bands, NELIOTA has recorded over 170 validated lunar impact flashes, while another ~90 have been characterized as suspected. We present statistical results concerning the sizes, the masses and the appearance frequency of the meteoroids in the vicinity of the Earth, as well as the temperatures developed during the impacts. Moreover, we present the capabilities of the Kryoneri telescope as a sensor for satellite tracking and the future plans regarding the provision of high-quality services for both the Planetary Defense activities of ESA (S2P/PDO) and the European Union's Space Surveillance and Tracking programme (EU/SST).Comment: 14 pages, 19 figures. Proceedings of the 2nd NEO and Debris Detection Conference, Darmstadt, Germany, 24-26 January 202

Prevalence of alexithymia and its association with anxiety and depression in a sample of Greek chronic obstructive pulmonary disease (COPD) outpatients

<p>Abstract</p> <p>Background</p> <p>Chronic obstructive pulmonary disease (COPD) is a major health problem, especially in adults over 40 years of age, and has a great social and economic impact. The psychological morbidity of COPD patients with regard to anxiety and depressive symptoms has been extensively studied in the past. However, few studies have investigated the prevalence of alexithymia in these patients, as well as its association with this comorbidity. Based on this fact, we studied the prevalence of alexithymia and its association with anxiety and depressive symptoms in COPD outpatients.</p> <p>Methods</p> <p>The present study included 167, randomly selected, outpatients diagnosed with COPD. Alexithymia, anxiety and depression were assessed using the Toronto Alexithymia Scale (TAS-20), Spielberger Trait Anxiety Inventory (STAI), and Beck Depression Inventory (BDI), respectively.</p> <p>Results</p> <p>The mean BDI score was 12.88 (SD: 7.7), mean STAI score 41.8 (SD: 11.0) and mean TAS-20 score 48.2 (SD: 11.5). No differences were observed between genders regarding age and alexithymia (t test <it>P </it>> 0.05), while female patients presented higher depression and trait anxiety scores than males (t test <it>P </it>< 0.05). Clinically significant levels of anxiety were present in 37.1% of men, and in 45.7% of women. The mean depression score was also higher than the corresponding mean score in the general population (one-sample t test <it>P </it>< 0.01), while 27.7% and 30.5% of the sample presented mild and moderate to severe depression, respectively. Finally, a strong correlation was observed between alexithymia, depression and anxiety.</p> <p>Conclusions</p> <p>This study confirms the high prevalence of anxiety and depression symptoms in Greek outpatients with COPD. The prevalence of alexithymia in COPD patients, contrary to what has been observed in patients with other chronic respiratory diseases, seem to be lower. However, we observed a strong association between alexithymia, depression and anxiety levels. This observation suggests that alexithymia should be taken into consideration when drafting specific psychotherapeutic interventions for these patients.</p