Cardiopulmonary deconditioning and plasma volume loss are not sufficient to provoke orthostatic hypertension.

Orthostatic hypertension, defined by an increase of systolic blood pressure (SBP) of ≥20 mmHg upon standing, harbors an increased cardiovascular risk. We pooled data from two rigorously conducted head-down tilt bedrest studies to test the hypothesis that cardiopulmonary deconditioning and hypovolemia predispose to orthostatic hypertension. With bedrest, peak VO2 decreased by 6 ± 4 mlO2/min/kg (p < 0.0001) and plasma volume by 367 ± 348 ml (p < 0.0001). Supine SBP increased from 127 ± 9 mmHg before to 133 ± 10 mmHg after bedrest (p < 0.0001). In participants with stable hemodynamics following head-up tilt, the incidence of orthostatic hypertension was 2 out of 67 participants before bedrest and 2 out of 57 after bedrest. We conclude that in most healthy persons, cardiovascular deconditioning and volume loss associated with long-term bedrest are not sufficient to cause orthostatic hypertension.

Effects of 30 days bed rest and exercise countermeasures on PBMC bioenergetics.

AIM: Altered mitochondrial function across various tissues is a key determinant of spaceflight-induced physical deconditioning. In comparison to tissue biopsies, blood cell bioenergetics holds promise as a systemic and more readily accessible biomarker, which was evaluated during head-down tilt bed rest (HDTBR), an established ground-based analog for spaceflight-induced physiological changes in humans. More specifically, this study explored the effects of HDTBR and an exercise countermeasure on mitochondrial respiration in peripheral blood mononuclear cells (PBMCs). METHODS: We subjected 24 healthy participants to a strict 30-day HDTBR protocol. The control group (n = 12) underwent HDTBR only, while the countermeasure group (n = 12) engaged in regular supine cycling exercise followed by veno-occlusive thigh cuffs post-exercise for 6 h. We assessed routine blood parameters 14 days before bed rest, the respiratory capacity of PBMCs via high-resolution respirometry, and citrate synthase activity 2 days before and at day 30 of bed rest. We confirmed PBMC composition by flow cytometry. RESULTS: The change of the PBMC maximal oxidative phosphorylation capacity (OXPHOS) amounted to an 11% increase in the countermeasure group, while it decreased by 10% in the control group (p = 0.04). The limitation of OXPHOS increased in control only while other respiratory states were not affected by either intervention. Correlation analysis revealed positive associations between white blood cells, lymphocytes, and basophils with PBMC bioenergetics in both groups. CONCLUSION: This study reveals that a regular exercise countermeasure has a positive impact on PBMC mitochondrial function, confirming the potential application of blood cell bioenergetics for human spaceflight.

[Molecular biological identification of fungal pathogens in FFPE tissue from cases of cephalic mycosis]. / Molekularbiologischer Erregernachweis aus FFPE-Proben bei zephaler Mykose.

BACKGROUND: Due to the lack of histopathological differentiation the unequivocal identification of fungal pathogens is rarely possible. In order to understand the pathogen spectrum causing cephalic mycosis the use of alternative methods is essential. MATERIAL AND METHODS: In a retrospective study 24 formalin-fixed, paraffin-embedded (FFPE) samples from patients with histologically confirmed cerebral or cephalic mycosis were analyzed with molecular biological methods. RESULTS: In two samples obtained during the patients' lifetime human as well as fungal DNA was detected, making an unambiguous diagnosis possible. For tissue that had been fixed over a longer period, detection of human and fungal DNA was possible merely in 60% and 47 % of the samples, respectively. Most frequently diagnosed were aspergillosis (n = 9), followed by mucormycosis (n = 2) and imported blastomycosis (n = 1). CONCLUSIONS: Using biopsy material a DNA analysis seems promising although only with limited success using brain samples taken at autopsy which have been fixed over a longer period. For unambiguous retrospective diagnostics of pathogens when cephalic mycosis is suspected, the sample extraction for postmortem diagnostics should be performed prior to a long period of formalin fixation.

Effect of interaction with micelles on the excited-state optical properties of zinc porphyrins and J-aggregates formation.

This work reports on the photophysical properties of zinc porphyrins meso-tetrakis methylpyridiniumyl (Zn(2+)TMPyP) and meso-tetrakis sulfonatophenyl (Zn(2+)TPPS) in homogeneous aqueous solutions and in the presence of sodium dodecyl sulfate (SDS) and cetyltrimethyl ammonium bromide (CTAB) micelles. The excited-state dynamic was investigated with the Z-scan technique, UV-Vis absorption, and fluorescence spectroscopy. Photophysical parameters were obtained by analyzing the experimental data with a conventional five-energy-level diagram. The interaction of the charged side porphyrin groups with oppositely charged surfactants can reduce the electrostatic repulsion between porphyrin molecules leading to aggregation, which affected the porphyrin characteristics such as absorption cross-sections, lifetimes and quantum yields. The interaction between anionic ZnTPPS with cationic CTAB micelles induced the formation of porphyrin J-aggregates, while this effect was not observed in the interaction of ZnTMPyP with SDS micelles. This difference is, probably, due to the difference in electrostatic repulsion between the porphyrin molecules. The insights obtained by these results are important for the understanding of the photophysical behavior of porphyrins, regarding potential applications in pharmacokinetics as encapsulation of photosensitizer for drug delivery systems and in its interaction with cellular membrane.

Experimental and theoretical investigation of optical nonlinearities in (nitrovinyl)-1H-pyrazole derivative.

This work reports on the optical nonlinearities of a newly synthesized pyrazole derivative, namely (E)-1-(4-chlorophenyl)-4-(2-nitrovinyl)-1H-pyrazole. The Z-scan technique with femtosecond laser pulses was used to determine the two-photon absorption (2PA) cross-section spectrum, which presents a maximum of 67 GM at 690 nm. We have combined hyper-Rayleigh scattering (HRS) experiments and second-order Møller-Plesset perturbation theory (MP2) calculations to study the first hyperpolarizability (ß(HRS)). It was found that the MP2/6-311+G(d) model, taking into account solvent and dispersion effects, provides the ß(HRS) value of 40×10(-30) cm(5)/esu for the compound, in good agreement with the experimental result of 45±2×10(-30) cm(5)/esu.

Polarization effect on the two-photon absorption of a chiral compound.

In this report, we investigate the polarization effect (linear, elliptical and circular) on the two-photon absorption (2PA) properties of a chiral compound based in azoaromatic moieties using the femtosecond Z-scan technique with low repetition rate and low pulse energy. We observed a strong 2PA modulation between 800 nm and 960 nm as a function the polarization changes from linear through elliptical to circular. Such results were interpreted employing the sum-over-essential states approach, which allowed us to model the 2PA circular-linear dichroism effect and to identifier the overlapping of the excited electronic states responsible by the 2PA allowed band.

Generation of copper nanoparticles induced by fs-laser irradiation in borosilicate glass.

Glasses containing metallic nanoparticles are promising materials for technological applications in optics and photonics. Although several methods are available to generate nanoparticles in glass, only femtosecond lasers allow controlling it three-dimensionally. In this direction, the present work investigates the generation of copper nanoparticles on the surface and in the bulk of a borosilicate glass by fs-laser irradiation. We verified the formation of copper nanoparticles, after heat treatment, by UV-Vis absorption, transmission electron microscopy and electron diffraction. A preferential growth of copper nanoparticles was observed in the bottom of the irradiated region, which was attributed to self-focusing in the glass.

Femtosecond laser induced synthesis of Au nanoparticles mediated by chitosan.

This paper reports the synthesis of Au nanoparticles by 30-fs pulses irradiation of a sample containing HAuCl4 and chitosan, a biopolymer used as reducing agent and stabilizer. We observed that it is a multi-photon induced process, with a threshold irradiance of 3.8 × 10(11) W/cm2 at 790 nm. By transmission electron microscopy we observed nanoparticles from 8 to 50 nm with distinct shapes. Infrared spectroscopy indicated that the reduction of gold and consequent production of nanoparticles is related to the fs-pulse induced oxidation of hydroxyl to carbonyl groups in chitosan.

Next-generation sequencing reveals regional differences of the α-synuclein methylation state independent of Lewy body disease.

The α-synuclein gene (SNCA) plays a major role in the aetiology of Lewy body disease (LBD) including Parkinson's disease (PD). Point mutations and genetic alterations causing elevated gene expression are causally linked to familial PD. To what extent epigenetic changes play a role in the regulation of α-synuclein expression and may contribute to the aetiology of sporadic LBD is a matter of debate. We analysed the methylation state of the promoter region and a CpG-rich region of intron 1 of α-synuclein in several brain regions in sporadic LBD and controls using 454 GS-FLX-based high-resolution bisulphite sequencing. Our results indicate that there are significant differences in the level of methylation between different brain areas. The overall methylation levels in the promoter and intron 1 of α-synuclein are rather low in controls and-in contrast to previously reported findings-are not significantly different from LBD. However, single CpG analysis revealed significant hyper- and hypomethylation at different positions in various brain regions and LBD stages. A slight overall increase in methylation related to LBD patients' age was detected.

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.

Third-order nonlinear spectra and optical limiting of lead oxifluoroborate glasses.

We have determined two-photon absorption and nonlinear refraction spectra of the 50BO(1.5) - (50-x)PbF(2) - xPbO glasses (with x = 25, 35, 50 cationic %) at the range of the 470 and 1550 nm. The replacement of fluor atoms by oxygen leads to an increase in the third-order susceptibility, due to the formation of non-bridging oxygens (NBO). The nonlinear index of refraction is one order of magnitude higher than the one for fused silica, and it increases almost twice for the sample with x = 50. This sample has also shown promising features for all-optical switching as well as for optical limiting.

Experimental and theoretical study of two-photon absorption in nitrofuran derivatives: Promising compounds for photochemotherapy.

We report experimental and theoretical studies of the two-photon absorption spectrum of two nitrofuran derivatives: nitrofurantoine, (1-(5-nitro-2-furfurilideneamine)-hidantoine) and quinifuryl, 2-(5(')-nitro-2(')-furanyl)ethenyl-4-{N-[4(')-(N,N-diethylamino)-1(')-methylbutyl]carbamoyl} quinoline. Both molecules are representative of a family of 5-nitrofuran-ethenyl-quinoline drugs that have been demonstrated to display high toxicity to various species of transformed cells in the dark. We determine the two-photon absorption cross-section for both compounds, from 560 to 880 nm, which present peak values of 64 GM for quinifuryl and 20 GM for nitrofurantoine (1 GM = 1×10(-50)cm(4).s.photon(-1)). Besides, theoretical calculations employing the linear and quadratic response functions were carried out at the density functional theory level to aid the interpretations of the experimental results. The theoretical results yielded oscillator strengths, two-photon transition probabilities, and transition energies, which are in good agreement with the experimental data. A higher number of allowed electronic transitions was identified for quinifuryl in comparison to nitrofurantoine by the theoretical calculations. Due to the planar structure of both compounds, the differences in the two-photon absorption cross-section values are a consequence of their distinct conjugation lengths.

Resonant nonlinear absorption in Zn-phthalocyanines.

In this work, we investigate the nonlinear absorption dynamics of Zn phthalocyanine in dimethyl sulfoxide (DMSO). We used single pulse and pulse train Z-scan techniques to determine the dynamics and absorption cross-sections of singlet and triplet states at 532 nm. The excited singlet state absorption cross-section was determined to be 3.2 times higher than the ground state one, giving rise to reverse saturable absorption. We also observed that reverse saturable absorption occurs from the triplet state, after its population by intersystem crossing, whose characteristic time was determined to be 8.9 ns. The triplet state absorption cross-section determined is 2.6 times higher than the ground state one. In addition, we used the white light continuum Z-scan to evaluate the singlet excited state spectrum from 450 to 710 nm. The results show two well-defined regions, one above 600 nm, where reverse saturable absorption is predominant. Below 600 nm, we detected a strong saturable absorption. A three-energy-level diagram was used to explain the experimental results, leading to the excited state absorption cross-section determination from 450 nm up to 710 nm.

Excited state dynamics of meso-tetra(sulphonatophenyl) metalloporphyrins.

The excited state dynamics of Zn2+, Fe3+, and Mn3+ meso-tetra(sulfonatophenyl) porphyrin complexes were investigated with a Z-scan technique at 532 nm using 70 ps and 120 fs single pulses and 200 ns pulse trains of a Q-switched and mode locked laser. We determined the characteristic interconversion and intersystem crossing times, quantum yields of the excited S1 state, and S1 --> Sn and T1 --> Tn transition cross-sections. The ground state cross-sections were obtained using UV-vis absorption spectroscopy, and a five-energy-level diagram was used to yield the photophysical parameters mentioned previously.

Two-photon absorption dependence on the temperature for azoaromatic compounds: effect of molecular conformation.

This work reports on the effect of temperature on the two-photon absorption cross section of azoaromatic chromophores. A linear decrease in the two-photon absorption cross section with the temperature was observed for several azochromophores. This process was characterized by introducing a two-photon absorption thermal coefficient (ddelta/dT), whose typical values are approximately 2GM/degrees C for all the azochromophores studied here. Such an effect was attributed to thermal induced molecular conformation changes, described by the sum-over-states model and semiempirical calculations, which affect the molecular dipole moments. The characterization of the phenomenon reported here for other nonlinear materials can help in the design of specific applications using two-photon absorption.

Excited state absorption spectrum of chlorophyll a obtained with white-light continuum.

The study of excited state properties of chlorophyll a is a subject of foremost interest, given that it plays important roles in biological process and has also been proposed for applications in photonics. This work reports on the excited state absorption spectrum of chlorophyll a solution from 460 to 700 nm, obtained through the white-light continuum Z-scan technique. Saturation of absorption was observed due to the ground state depletion, induced by the white-light continuum region that is resonant with the Q band of chlorophyll a. The authors also observed reverse saturation of absorption related to the excitation from the first excited state to a higher energy level for wavelengths below 640 nm. An energy-level diagram, based on the electronic states of chlorophyll a, was employed to interpret their results, revealing that more states than the ones related to the Q and B bands participate in the excited state absorption of this molecule.

Nonlinear absorption dynamics in tetrapyridyl metalloporphyrins.

Nonlinear absorption dynamics of Zn(2+), Cu(2+), and Ni(2+) tetrapyridyl porphyrins in chloroform/methanol solutions were investigated at 532 nm with the Z-scan technique. Additional techniques such as UV-vis absorption spectroscopy and time-resolved fluorescence were used to obtain parameters that are important for the analysis of the population dynamics. A marked difference was observed in the nonlinear absorption and excited-state dynamics of closed (ZnTPyP)- and open-shell metalloporphyrins (CuTPyP and NiTPyP). ZnTPyP presents a reverse saturable absorption whose dynamics can be completely described by means of a simple five-energy-level diagram. On the other hand, CuTPyP and NiTPyP have a different excited-state dynamics, presenting a saturable absorption behavior and faster relaxation rates that were attributed to the presence of unfilled d shells of the central ion.

Experimental observation of light-induced solitary waves of analyte bands in capillary electrophoresis.

The phenomenon of electrophoresis in free solution has been studied theoretically down to the molecular level for decades. In addition, intermolecular photo-induced proton transfer reactions, which occur in a wide class of molecules (phenols and aminoarenes) as well as proteins (green fluorescent protein), were also studied extensively. However, the study of the effect of light-induced electrophoretic mobility changes of the analytes in electrophoresis was begun only recently. In the present work, capillary zone electrophoresis was chosen as the environment to measure the magnitude of these electrophoretic mobility shifts induced by light. Background electrolytes (running electrolytes) with high refractive indices were developed, allowing the capillary to work like an optical fiber. The experimental conditions for obtaining stable coupling and guided laser light along the liquid core are discussed. Experimental evidence of band compression is observed, leading to a solitary wave behavior of the analyte band (2-naphthol). These solitary waves result from competition between thermal diffusion (dispersion mechanism) and a nonlinear (band compression) effect due to the combined electrophoresis phenomenon and absorption of guided light by the molecules of the band (which are subjected to a "reversible intermolecular proton transfer reaction" as one of their decay routes). The possibilities of applying this effect to different methods and techniques are also discussed.