Polarimetric measurements in multiphoton microscopy can reveal information about the local molecular order of a sample. However, the presence of a dichroic through which the excitation beam propagates will generally scramble its polarization. We propose a simple scheme whereby a second properly‐oriented compensation dichroic is used to negate any alteration regardless of the wavelength and the initial polarization. We demonstrate how this robust and rapid approach simplifies polarimetric measurements in second‐harmonic generation, two‐photon excited fluorescence and coherent anti‐Stokes Raman scattering.
Illustration of the polarization maintaining strategy with the compensating dichroic oriented such that its s‐ and p‐axes are interchanged with these of the primary dichroic. 相似文献
A carageenophyte, Eucheuma denticulatum (Solieriaceae, Rhodophyta) at a mariculture farm in Bali, Indonesia (Photo by R. Terada). Characteristic thermal and irradiance responses on the photosynthesis of Indonesian E. denticulatum and Kappaphycus alvarezii are reported by Borlongan et al. in this issue. Cover picture from: Article link here
Primary segregative cell division in Struvea okamurae (Photos by A. Hasebe). The same apical portion of a cylindrical cell was photographed in order from left to right 72 min, 109 min, 126 min, 136 min, 148 min, 294 min, and 492 min after the light period had begun. See Okuda et al. See pages 219–229. Cover picture from: Article link here
Eisenia bicyclis (Kjellman) Setchell. A kelp bed dominated by the alga in Shizugawa Bay, Miyagi Prefecture, northeastern Japan (December 26, 2014). Endo et al. in this issue investigated combined effects of abiotic factors on juvenile sporophytes of this kelp (Photo by H. Endo). Cover picture from: Article link here
Morphological features of Monorhizochytrium globosum NBRC 112723 in seawater/seaweed culture. A single ectoplasmic net penetrated into Pyropia sp. (top left). Continuous observations of zoospore formation (from top center to right bottom); after cleavage of the multinucleate protoplasm of the zoosporangium, each uninucleate cell developed into a zoospore. See Doi and Honda in pages 188–201. Cover picture from: Article link here
The paper presents problems and solutions related to hyperspectral image pre‐processing. New methods of preliminary image analysis are proposed. The paper shows problems occurring in Matlab when trying to analyse this type of images. Moreover, new methods are discussed which provide the source code in Matlab that can be used in practice without any licensing restrictions.
The proposed application and sample result of hyperspectral image analysis. 相似文献
Habitat and morphology of Prasiola from the marine environment in Japan (Photos by W. A. Nelson). Top left: P. calophylla on a concrete wharf in Akkeshi Bay. Bottom left: P. delicata growing next to lichens and guano on Daikokujima. Right: Prasiola cf. meridionalis on rockfaces on Daikokujima. See Sutherland et al. in this issue for details. Cover picture from: Prasiola (Prasiolales, Trebouxiophyceae) in Japan: a survey of freshwater populations and new records of marine taxa, Sutherland J et al. See pages 110‐117. Article link here
Risk of recurrence is a major problem in breast cancer management. Currently available prognostic markers have several disadvantages including low sensitivity and specificity, highlighting the need for new prognostic techniques. One of the candidate techniques is serum‐based Raman spectroscopy (RS). In this study, feasibility of using RS to distinguish ‘pre’ from ‘post’ breast tumor resection serum in rats was explored. Spectral analysis suggests change in proteins and amino acid profiles in ‘post’ compared to ‘pre‐surgical’ group. Principal‐Component‐Linear‐Discriminant‐Analysis shows 87% and 91% classification efficiency for ‘pre’ and ‘post‐surgical’ groups respectively. Thus, the study further supports efficacy of RS for theranostic applications.
Cover Image Melocactus sergipensis N.P. Taylor & M.V. Meiado (Cactaceae) at the holotype locality with limestone substrate in an area of Caatinga, Simão Dias municipality, Sergipe, Brazil. Photo taken by Marcos V. Meiado.
Mechanisms of renal autoregulation generate oscillations in arterial blood flow at several characteristic frequencies. Full‐field laser speckle flowmetry provides a real‐time imaging of superficial blood microcirculation. The possibility to detect changes in oscillatory dynamics is an important issue in biomedical applications. In this paper we show how laser power density affects quality of the recorded signal and improves detectability of temporal changes in microvascular perfusion.
Main flower‐visitng insects of Bidens fronds. Photographed by Bing Zhou in Jían City, Jiangxi Province, China. Cover picture from: Reproductive biological characteristics potentially contributed to invasiveness in an alien invasive plant Bidens frondosa, Yan XH et al. See pages 107–116. Article link here .
Collecting in New Ireland, Papua New Guinea. Upper left: coastal mangroves in Karu, Kaguso. Lower left: large mangrove trees distributed near Uparage village, and mangrove visitors. Right: Caloglossa thalli attached to an aerial root of a mangrove tree. Photos by M. Kamiya. See Kamiya et al. in this issue for details. Cover picture from: Article link here
Photodynamic therapy (PDT) is used for skin treatments of premalignant and cancer lesions and recognized as a non‐invasive technique that combines tissue photosensitization and subsequent exposure to light to induce cell death. However, it is limited to the treatment of superficial lesions, mainly due to the low cream penetration. Therefore, the improvement of transdermal distribution of aminolevulinic acid (ALA) is needed. In this study, the kinetics and homogeneity of production of ALA‐induced PpIX after the skin pre‐treatment with microneedles rollers of 0.5, 1.0 and 1.5 mm length were investigated. An improvement in homogeneity and production of PpIX was shown in a porcine model.
Widefield fluorescence imaging three hours after the topical application of ALA‐cream in the combined treatment with microeedles rollers. 相似文献
Male reproductive health in both humans and animals is an important research field in biological study. In order to characterize the morphology, the motility and the concentration of the sperm cells, which are the most important parameters to feature them, digital holography demonstrated to be an attractive technique. Indeed, it is a label‐free, non‐invasive and high‐resolution method that enables the characterization of live specimen. The review is intended both for summarizing the state‐of‐art on the semen analysis and recent achievement obtained by means of digital holography and for exploring new possible applications of digital holography in this field.
Quantitative phase maps of living swimming spermatozoa. 相似文献
Common perception regards the nucleus as a densely packed object with higher refractive index (RI) and mass density than the surrounding cytoplasm. Here, the volume of isolated nuclei is systematically varied by electrostatic and osmotic conditions as well as drug treatments that modify chromatin conformation. The refractive index and dry mass of isolated nuclei is derived from quantitative phase measurements using digital holographic microscopy (DHM). Surprisingly, the cell nucleus is found to have a lower RI and mass density than the cytoplasm in four different cell lines and throughout the cell cycle. This result has important implications for conceptualizing light tissue interactions as well as biological processes in cells.
Fluorescence lifetime imaging (FLIm) and Raman spectroscopy are two promising methods to support morphological intravascular imaging techniques with chemical contrast. Both approaches are complementary and may also be used in combination with OCT/IVUS to add chemical specificity to these morphologic intravascular imaging modalities. In this contribution, both modalities were simultaneously acquired from two human coronary specimens using a bimodal probe. A previously trained SVM model was used to interpret the fluorescence lifetime data; integrated band intensities displayed in RGB false color images were used to interpret the Raman data. Both modalities demonstrate unique strengths and weaknesses and these will be discussed in comparison to histologic analyses from the two coronary arteries imaged.
Photodamage, induced by femtosecond laser radiation, was studied in thick samples of human skin tissue (healthy skin and neoplastic lesions). Photobleaching, photoionization, and thermomechanical damage effects were characterized comparatively. The laser power dependence of the damage rates allowed to connect macroscopic effects to underlying molecular processes. Optical effects were correlated to histopathological changes. Tissue alterations were found only from thermomechanical cavitation and limited to superficial layers of the epidermis. From the depth‐dependencies of all damage thresholds a depth‐dependent power‐compensation scheme was defined allowing for damage‐free deep tissue optical biopsy.
Damage‐induced luminescence pattern for different excitation powers and a corresponding threshold analysis. 相似文献
Traditional approaches to characterize stem cell differentiation are time‐consuming, lengthy and invasive. Here, Raman microspectroscopy (RM) and atomic force microscopy (AFM) – both considered as non‐invasive techniques – are applied to detect the biochemical and biophysical properties of trophoblast derived stem‐like cells incubated up to 10 days under conditions designed to induce differentiation. Significant biochemical and biophysical differences between control cells and differentiated cells were observed. Quantitative real time PCR was also applied to analyze gene expression. The relationship between cell differentiation and associated cellular biochemical and biomechanical changes were discussed.
The understanding of transdermal substance penetration pathways remains an important field for the development of future topical drugs and cosmetics. Laser Doppler flowmetry is a well‐established method for evaluating cutaneous perfusion. In a study on 6 healthy male volunteers, we topically applied the vasoactive substance benzyl nicotinate on two test areas with open and obturated hair follicles and measured changes in the blood flow by Doppler flowmetry. Contrary to occluded follicles, the application onto the test area with open follicles led to a statistically significant perfusion increase within the first 5 minutes, emphasizing the importance of the follicular pathway for epidermal penetration.
We report on transient membrane perforation of living cancer cells using plasmonic gold nanoparticles (AuNPs) enhanced single near infrared (NIR) femtosecond (fs) laser pulse. Under optimized laser energy fluence, single pulse treatment (τ = 45 fs, λ = 800 nm) resulted in 77% cell perforation efficiency and 90% cell viability. Using dark field and ultrafast imaging, we demonstrated that the generation of submicron bubbles around the AuNPs is the necessary condition for the cell membrane perforation. AuNP clustering increased drastically the bubble generation efficiency, thus enabling an effective laser treatment using low energy dose in the NIR optical therapeutical window.
Schematic representation of single femtosecond laser pulse plasmonic bubble generation in the vicinity of a cell. 相似文献
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