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The mélange of light localization and laser emission is particularly fascinating due to the specific features of each distinctive lasing source, accompanied by exclusive emission properties of the localized modes. In this manuscript we demonstrate light amplification and random laser effects from special dye-doped confined micrometric systems. We physically characterize the particular sample configurations for low and high power pumping conditions from spectral point of view. Analysis of far field spatial emission confirms that light localization and random lasing occurs in our systems upon exceeding a certain input energy threshold. In addition, the presented small-size optical systems are also highly robust and prone for immediate exploitation in the micro technological arena. [ABSTRACT FROM AUTHOR]

By means of Monte Carlo simulations, we investigated the nucleation of polymers in frustrated spaces, i.e. in spaces where one dimension is much smaller (or larger) than other (or others). The obtained results were compared with those predicted by the Avrami equation. In the case of the spontaneous nucleation, we found similarities with respect to the ordinary crystallization case, but the Avrami index has smaller values. For instantaneous nucleation conditions, we observed to have two distinctive regimes: 3- dimensional crystallization at the beginning of the process, followed by a behavior which is similar with the one that occur in spaces with low dimensionalities. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the process of phase transformation in polymeric materials by imposing instantaneous nucleation conditions in the employed Monte Carlo type simulations. We calculated the overall crystallization rate constants and the Avrami indices for various simulation circumstances and the obtained results were equivalent with those predicted by the Avrami equation. The dependence of the crystallization rate constant on the growth velocity and concentration of the nuclei was also investigated and a comparison was made with the already existing theory. [ABSTRACT FROM AUTHOR]

Using Monte Carlo simulations, we investigated the sporadic nucleation of polymers and the results were compared with those obtained from the Avrami equation. From the simulation data, we calculated the overall crystallization rate constants and the Avrami indices. We considered isotropic growth of the nuclei in 1,2 and 3 dimension, the obtained results for the Avrami indices being in excellent agreement with theory and experiments. We also investigated the dependence of the overall crystallization rate constant on the crystallization velocity. [ABSTRACT FROM AUTHOR]

In this manuscript we present interesting scientific results following the physical characterization of thin polyaniline polymer films achieved by means of Glancing Angle Deposition (GLAD) method. Aniline monomer was used as precursor in a cold plasma polymerization chamber and the resulting thin films were investigated by various physical techniques (Atomic Force Microscopy - AFM and Scanning Electron Microscopy - SEM), while also considering their conductive electrical properties. [ABSTRACT FROM AUTHOR]

Obtaining of conjugate oligomers/polymers as thin films with a low degree of crosslinkage and semiconducting properties deposited by plasma polymerization represents an interesting challenge. A plasma-polymerization experimental set-up is developed to use liquid monomers and solid-liquid mixtures as starting materials. In this work, mixtures of p-xylene monomer with isolated polycyclic aromatic precursors (biphenyl and quarterphenyl) are plasma polymerized to obtain polymer films with specific properties related to organic electronic applications. The characteristics of obtained films are analyzed by FT-IR spectroscopy, atomic force microscopy (AFM). In order to explain the conduction mechanism the current-voltage characteristics in asymmetric electrode configuration are investigated. [ABSTRACT FROM AUTHOR]

We report a Monte Carlo simulation based on the Lebwohl-Lasher model for characterizing the molecular director configuration in a nematic liquid crystal having a spherocylindrical particle immersed inside. We describe the molecular orientation and spatial behavior of the order parameter and we retrieve the presence of a disclination line with the shape of the Saturn ring defect. By applying an electric field, the order inside the simulation cell is considerably changed and we find that the plane of the disclination line is moved perpendicular to the field direction. As the intensity of the field is increaseed the disclination line eventually disappears, the order inside the cell becoming uniaxial. [ABSTRACT FROM AUTHOR]

By using Monte Carlo simulation we study the effect of an electric field on a negative dielectric anisotropy nematic liquid crystal presenting a spherocylindrical shaped particle located inside. We characterize the orientation of the nematic molecules inside the simulation box by means of the scalar and tensorial order parameter, field order parameter and radial order parameter, We also analyze how the system develops a Saturn ring type disclination line having the plane parallel with the direction of the applied electric field [ABSTRACT FROM AUTHOR]

Background: Urachal cancer (UrC) is a rare disease with limited availability of representative incidence and clinical data. Although, the prevalence is accounting for less than 1% of bladder tumors, the 5-year survival rate is around only 50% for patients with resectable tumors, and even worse for patients with metastatic disease. Due to the lack of comprehensive prospective studies, our current knowledge of UrC is still limited., Objective: The present study aimed to summarize the available registry-based studies with unselected UrC patients to evaluate its incidence and clinicopathological characteristics., Material and Methods: We conducted a systematic literature search of registry-based UrC publications on the 15th of May 2023 in 5 databases, which identified 4,748 publications. After duplicate removal and selection by 2 independent investigators, 6 publications proved to be appropriate for the final meta-analysis. Estimated incidence and clinicopathological parameters were extracted., Results: Estimated incidence ranged between 0.022 and 0.060/ 100.000 person-years, with the highest occurrence in Japan and the lowest in Canada, while the random effect model calculated an overall incidence rate of 0.04 (95%CI: 0.03-0.05) 100.000 person-years. The median age at first diagnosis was 60 years (range: 58-64). The female to male ratio was 2:3. Lymph node or distant metastases were present in 9% and 14% of patients. The predominant tumour type was adenocarcinoma (86%) followed by urothelial carcinoma (12%) and squamous cell carcinoma (2%). The 5-year survival rate was 51.0% with 95%CI: 45.2-57.4., Conclusions: Our study provides an up-to-date comparison of estimated incidence rates between 6 countries of 3 continents based on rigorously selected registry-based studies. The results suggest low incidence rates for UrC with considerable geographic differences. The present meta-analysis provides unbiased registry-based data on the incidence, clinicopathological parameters and survival of UrC., Competing Interests: Declaration of competing interest The authors declare no potential conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Probiotics are often used to prevent antibiotic-induced low-diversity dysbiosis, however their effect is not yet sufficiently summarized in this regard. We aimed to investigate the effects of concurrent probiotic supplementation on gut microbiome composition during antibiotic therapy., Methods: We performed a systematic review and meta-analysis of randomized controlled trials reporting the differences in gut microbiome diversity between patients on antibiotic therapy with and without concomitant probiotic supplementation. The systematic search was performed in three databases (MEDLINE (via PubMed), Embase, and Cochrane Central Register of Controlled Trials (CENTRAL)) without filters on 15 October 2021. A random-effects model was used to estimate pooled mean differences (MD) with 95% confidence intervals (CI). This review was registered on PROSPERO (CRD42021282983)., Results: Of 11,769 identified articles, 15 were eligible in the systematic review and 5 in the meta-analyses. Quantitative data synthesis for Shannon (MD = 0.23, 95% CI: [(-)0.06-0.51]), Chao1 (MD = 11.59 [(-)18.42-41.60]) and observed OTUs (operational taxonomic unit) (MD = 17.15 [(-)9.43-43.73]) diversity indices revealed no significant difference between probiotic supplemented and control groups. Lacking data prevented meta-analyzing other diversity indices; however, most of the included studies reported no difference in the other reported α- and ß-diversity indices between the groups. Changes in the taxonomic composition varied across the eligible studies but tended to be similar in both groups. However, they showed a potential tendency to restore baseline levels in both groups after 3-8 weeks. This is the first meta-analysis and the most comprehensive review of the topic to date using high quality methods. The limited number of studies and low sample sizes are the main limitations of our study. Moreover, there was high variability across the studies regarding the indication of antibiotic therapy and the type, dose, and duration of antimicrobials and probiotics., Conclusions: Our results showed that probiotic supplementation during antibiotic therapy was not found to be influential on gut microbiome diversity indices. Defining appropriate microbiome diversity indices, their standard ranges, and their clinical relevance would be crucial., (© 2023. The Author(s).)

This work is focused on the structural and morphological investigations of polyaniline and poly( o -anisidine) polymers generated in a direct current glow discharge plasma, in the vapors of the monomers, without a buffer gas, using an oblique angle-positioned substrate configuration. By atomic force microscopy and scanning electron microscopy we identified the formation of worm-like interlinked structures on the surface of the polyaniline layers, the layers being compact in the bulk. The poly( o -anisidine) layers are flat with no kind of structures on their surfaces. By Fourier transform infrared spectroscopy we identified the main IR bands characteristic of polyaniline and poly( o -anisidine), confirming that the polyaniline chemical structure is in the emeraldine form. The IR band from 1070 cm -1 was attributed to the emeraldine salt form of polyaniline as an indication of its doping with H⁺. The appearance of the IR band at 1155 cm -1 also indicates the conducting protonated of polyaniline. The X-ray diffraction revealed the formation of crystalline domains embedded in an amorphous matrix within the polyaniline layers. The interchain separation length of 3.59 Å is also an indicator of the conductive character of the polymers. The X-ray diffraction pattern of poly( o -anisidine) highlights the semi-crystalline nature of the layers. The electrical conductivities of polyaniline and poly( o -anisidine) layers and their dependence with temperature are also investigated., Competing Interests: The authors declare no conflict of interest.

The study of electromagnetic waves propagation in periodically structured dielectrics and the linear and nonlinear optical phenomena in disordered systems doped with gain media represent one of the most challenging and exciting scientific areas of the past decade. Lasing and Random Lasers (RL) are fascinating examples of topics that synergize multiple scattering of light and optical amplification and lately have been the subject of intense theoretical and experimental studies. In this manuscript we demonstrate laser action in a new category of materials, namely dye doped ionic liquids. Ionic liquids prove to be perfect candidates for building, as shown, a series of exotic boundaryless or confined compact laser systems. Lasing is presented in standard wedge cells, freely suspended ionic liquid films and droplets. The optical emission properties are investigated in terms of spectral analysis, below and above lasing energy threshold behavior, emission efficiency, far field spatial laser modes intensity profiling, temporal emission behavior etc. As demonstrated, these materials can be employed as optimal near future replacements of conventional flammable solvents in already available dye laser instruments.

In the present study, we tested right- and left-handed participants in a Poffenberger paradigm with bimanual responses and hands either in an anatomical or in a left-right inverted posture. We observed a significant positive crossed-uncrossed difference (CUD) in RTs for both manual dominance groups and both response postures. These results rule out an explanation of the CUD in terms of stimulus-response spatial compatibility (SRSC) and provide convincing evidence on the important role of interhemispheric callosal transfer in bimanual responding in right- as well as left-handed individuals.

An anisotropic nanopatterning method, based on a technique of atomic force microscopy (AFM) scribing of a thin polyimide film, is used to generate an alignment layer whose topography depends on the writing direction. Detailed experimental measurements are presented for the topographical anisotropy that arises when the polyimide alignment layer is scribed parallel and antiparallel to the AFM cantilever orientation. By means of a novel nanotomographic approach, the optical retardation δ of an alignable birefringent liquid that covers the scribed substrate is measured with unprecedented resolution of only a few tens of nanometers. In this technique a thin optical fiber is raster-scanned at several fixed heights inside the birefringent liquid, and the transmitted polarized light is collected downstream. The optical retardation δ from the fiber's tip to the polyimide interface was measured as a function of position x,y,z, with the results reflecting the spatially varying depth of the medium due to the polymer film surface topography. Theoretical calculations for δ are in excellent agreement with both the topographical and the high resolution nanoimaging experimental results obtained.

A statistical analysis of random lasing events observed in dye-doped nematic-liquid-crystal films is reported. The occurrence of random laser action in such complex fluids is due to residual resonances in the multiple scattering of spontaneously emitted photons. The Shannon entropy and a local-Poisson test are used here in order to quantitatively characterize the chaotic behavior of laser spikes and gain further understanding of the mechanisms underlying the lasing effect in strongly scattering organized fluids arising by an unexpected interplay of localization and amplification.

Random lasing in fully disordered systems having organic and inorganic nature has been the subject of extensive studies since the beginning of the past decade. The interest mainly emerges from the unexpected role played by disorder in the laser action. The disorder was considered detrimental for the optical feedback in cavity laser, until it was demonstrated that multiple-scattering materials including a gain medium act as random laser. Here, a completely new approach is reported, where freely suspended complex fluid films doped with fluorescent molecules under optical excitation generate narrowband lasing peaks. The constellation of localized modes is selected by properly choosing the gain profile. The idea to have laser action in absence of mirrors and boundaries realizes an unparalleled tunable and moldable laser source.

We report a detailed physical characterization of a novel array of organic distributed feedback microcavity lasers possessing a high ratio between the quality factor Q of the resonant cavity and its volume V. The optical microcavity was obtained by confining self-organized mesophases doped with fluorescent guest molecules into holographically patterned polymeric microchannels. The liquid crystal microchannels act as mirror-less cavity lasers, where the emitted laser light propagates along the liquid crystal helical axis behaving as Bragg resonator. This miniaturization process allows us to obtain a micro-laser array possessing an ultralow lasing threshold (25nJ/pulse) while having directional control on the lasing emission, a fine wavelength tunability and the control over the emission intensity.

Distributed feedback microstructures play a fundamental role in confining and manipulating light to obtain lasing in media with gain. Here, we present an innovative array of organic, color-tunable microlasers which are intrinsically phase locked. Dye-doped helixed liquid crystals were embedded within periodic, polymeric microchannels sculptured by light through a single-step process. The helical superstructure was oriented along the microchannels; the lasing was observed along the same direction at the red edge of the stop band. Several physical and technological advantages arise from this engineered heterostructure: a high quality factor of the cavity, ultralow lasing threshold, and thermal and electric control of the lasing wavelength and emission intensity. This level of integration of guest-host systems, embedded in artificially patterned small sized structures, might lead to new photonic chip architectures.