Improvement in the temporal contrast in the tens of ps range of the multi-PW Apollon laser front-end.

We demonstrate the impact of the optics roughness in Öffner stretchers used in chirped pulse amplification laser chains and how it is possible to improve the temporal contrast ratio in the temporal range of 10-100 ps by adequately choosing the optical quality of the key components. Experimental demonstration has been realized in the front-end source of the multi-petawatt (PW) laser facility Apollon, resulting in an enhancement of the contrast ratio by two to three orders of magnitude.

Isolation and identification of compounds from Kalanchoe pinnata having human alphaherpesvirus and vaccinia virus antiviral activity.

CONTEXT: Kalanchoe pinnata (Lam.) Pers. (Crassulaceae) is a succulent plant that is known for its traditional antivirus and antibacterial usage. OBJECTIVE: This work examines two compounds identified from the K. pinnata plant for their antivirus activity against human alphaherpesvirus (HHV) 1 and 2 and vaccinia virus (VACV). MATERIALS AND METHODS: Compounds KPB-100 and KPB-200 were isolated using HPLC and were identified using NMR and MS. Both compounds were tested in plaque reduction assay of HHV-2 wild type (WT) and VACV. Both compounds were then tested in virus spread inhibition and virus yield reduction (VYR) assays of VACV. KPB-100 was further tested in viral cytopathic effect (CPE) inhibition assay of HHV-2 TK-mutant and VYR assay of HHV-1 WT. RESULTS: KPB-100 and KPB-200 inhibited HHV-2 at IC50 values of 2.5 and 2.9 µg/mL, respectively, and VACV at IC50 values of 3.1 and 7.4 µg/mL, respectively, in plaque reduction assays. In virus spread inhibition assay of VACV KPB-100 and KPB-200 yielded IC50 values of 1.63 and 13.2 µg/mL, respectively, and KPB-100 showed a nearly 2-log reduction in virus in VYR assay of VACV at 20 µg/mL. Finally, KPB-100 inhibited HHV-2 TK- at an IC50 value of 4.5 µg/mL in CPE inhibition assay and HHV-1 at an IC90 of 3.0 µg/mL in VYR assay. DISCUSSION AND CONCLUSION: Both compounds are promising targets for synthetic optimization and in vivo study. KPB-100 in particular showed strong inhibition of all viruses tested.

Quantitative study of impact damage on yellow peaches based on reflectance, absorbance and Kubelka-Munk spectral data.

Impact damage is one of the main forms of damage during the postharvest transportation and processing of yellow peaches. Thus, a quantitative prediction of the impact damage degree of yellow peaches is significant for their postharvest grading. In the present study, mechanical parameters such as the damage area, absorbed energy and maximum force were obtained based on a single pendulum collision device and an intelligent data acquisition system. The reflection spectra (R) of the damaged areas of yellow peaches were collected by a hyperspectral imaging system and transformed into absorbance (A) spectra and Kubelka-Munk (K-M) spectra. The R, A and K-M spectra were preprocessed by standard normal variables (SNV), moving average (MA) and Gaussian filtering (GF). Partial least squares regression (PLSR) models and support vector regression (SVR) models based on original and preprocessed spectra were established, respectively. By comparative analysis, the spectral data with better prediction performance (raw or preprocessed spectra) were selected from all spectra, and the characteristic wavelengths were selected by competitive adaptive reweighted sampling (CARS) and uninformative variable elimination (UVE). The PLSR and SVR models based on characteristic wavelengths were established. The results revealed that the prediction performance of the K-M-GF-CARS-PLSR model is the best. For the damage area, absorbed energy and maximum force, the R P 2 and RMSEP of the K-M-GF-CARS-PLSR model were 0.870 and 77.865 mm2, 0.772 and 1.065 J, 0.895 and 47.996 N, respectively. Furthermore, the values of their RPD were 2.700, 1.768 and 3.050, respectively. The characteristic wavelengths of the model were 18.8%, 10.2% and 21.6%, respectively. The results of this study showed that there was a strong correlation between the mechanical parameters and K-M spectrum, which demonstrates the feasibility of quantitatively predicting the damage degree of yellow peaches based on the K-M spectrum. Therefore, the results of this work not only provide theoretical guidance for the postharvest grading of fruits, but also enrich the theoretical system of biomechanics.

Infrared (1.2-1.6 microm) luminescence in Cr4+:Yb3Al5O12 single crystal with 940 nm diode pumping.

Infrared (1.2-1.6 microm) luminescence in a ytterbium aluminium garnet (YbAG) crystal, doped with Cr (0.05at.%) ions, was investigated under CW laser diode pumping (lambda=940 nm). The Cr4+ emission band was observed with its peak at 1.34 microm and measured to be about 1.3 times with respect to Yb3+ IR luminescence (lambda=1.03 microm). We demonstrate that for the excitation wavelength of 940 nm Yb3+ ions act as sensitizers of the 3B2(3T2)-3B1(3A2) emission of Cr4+ ions. This crystal is promising as a high-efficient system for tunable laser (1.2-1.6 microm) output.

Freeze-dried rat bone marrow mesenchymal stem cell paracrine factors: a simplified novel material for skin wound therapy.

The mesenchymal stem cell (MSC) supernatant is well known as a rich source of autologous cytokines and universally used for tissue regeneration in current clinical medicine. However, the limitation of conditioned medium used in open-wound repair compels the need to find a more sophisticated way to take advantage of the trophic factors of MSCs. We have now fabricated a three-dimensional membrane from freeze-dried bone marrow mesenchymal stem cells-conditioned medium (FBMSC-CM) using a simple freeze-dried protocol. Scanning electron microscopy images showed the microstructure of the FBMSC-CM membrane (FBMSC-CMM) resembling a mesh containing growth factors. ELISA was used to test the paracrine factors retained in the FBMSC-CMM, and the results indicated that FBMSC-CMM withheld over 80% of the paracrine factors. Live/dead assays were adopted to test the toxicity of the FBMSC-CMM on cultured rat dermal fibroblasts, and the results confirmed its biological safety with low toxicity. Moreover, the FBMSC-CMM could significantly accelerate wound healing and enhance the neovascularization as well as epithelialization through strengthening the trophic factors in the wound bed as determined by immunohistochemical staining. Thus, the ability to maintain paracrine factors and enhance the effectiveness of these growth factors in the wound as well as the simple procedure and economical materials required for production qualifies the FBMSC-CMM to be a candidate biomaterial for open-wound regeneration.

Mesenchymal stem cells/multipotent mesenchymal stromal cells (MSCs): potential role in healing cutaneous chronic wounds.

Chronic wounds remain a major challenge in modern medicine and represent a significant health care burden. Several treatments have been suggested, but without a full understanding of the exact mechanism by which chronic wound occurs. Numerous studies have shown that mesenchymal stem cells/multipotent mesenchymal stromal cells (MSCs) may have therapeutic potential in healing cutaneous chronic wounds through various mechanisms. So far, a series of hypotheses have been proposed, but a holistic image of them is lacking. This review provides a systematic analysis of recent research in animal models and preclinical or clinic trails to evaluate the potential role of MSCs in chronic cutaneous wound healing. Most important, we highlight how mesenchymal stem cells could potentially revolutionize our approach to treating cutaneous chronic wounds. Special attention should be focused on ongoing research regarding the challenges in using and prospects of MSCs in clinical settings.

Optimization of the dynamic wavefront control of a pulsed kilojoule/nanosecond-petawatt laser facility.

The wavefront aberrations in a large-scale, flash-lamp-pumped, high-energy, high-power glass laser system can degrade considerably the quality of the final focal spot, and limit severely the repetition rate. The various aberrations induced on the Laboratoire pour l'Utilisation des Lasers Intenses (LULI), laser facility (LULI2000) throughout the amplification are identified and analyzed in detail. Based on these analyses, an optimized procedure for dynamic wavefront control is then designed and implemented. The lower-order Zernike aberrations can be effectively reduced by combining an adaptive-optics setup, comprising a bimorph deformable mirror and a four-wave lateral shearing interferometer, with a precise alignment system. This enables the laser chain to produce a reproducible focal spot close to the diffraction limit (Strehl ratio approximately 0.7). This allows also to increase the repetition rate, initially limited by the recovery time of the laser amplifiers, by a factor of 2 (one shot per hour). The proposed procedure provides an attractive alternative for dynamic correction of the wavefront aberrations of a laser facility as complex as the LULI2000.