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Background: The requirement for efficient and green conversion technologies has prompted hydrothermal processing as a promising treatment option for sustainable biorefinery industry. The treatment has been applied to process plenty of lignocellulose materials, yielding abundant high value-degraded products, especially the products in the liquid fraction. Therefore, it is essential to systematically evaluate the degraded products in aqueous fraction by comprehensive analysis and structural characterization during the treatment. Results: Rapeseed straw was hydrothermally treated at temperature ranging from 145 to 205 °C for various retention time (15, 30, 60 and 120 min), and the degraded polysaccharides and lignin products in aqueous phase were systematically evaluated by comprehensive analysis and structural characterization. Results showed that with an increase of severity, the polymers were gradually depolymerized resulting in a decrease of the molecular weight from 8430 (log R0 3.26) to 2130 g/mol (log R0 5.08), an increase of oligosaccharides from 19.44 (log R0 2.88) to 99.94 g/kg (log R0 4.32) and an increase of monosaccharides from 0.91 (log R0 2.88) to 30.43 g/kg (log R0 4.37). With the increase of monosaccharide degradation components (8.26 to 125.68 g/kg), the saccharides gradually decreased after its maximum value. The maximum yield of oligosaccharides (99.94 g/kg) accompanying a relatively low level of monosaccharides (17.77 g/kg) was obtained at a high temperature (190 °C) for a short reaction time (15 min). The degraded polysaccharides had a linear backbone of (1 → 4)-linked β-d-xylopyranosyl xylan decorated with branches based on 2D NMR spectra analysis. Lignin was strongly condensed with a decrease of S/G ratio as the severity increased. The yields of the degraded constitutions have a incomplete linear correlation with the treatment severity. Conclusions: The liquid fractions obtained from hydrothermal treatment were subjected to comprehensive analysis and structural characterization. Results indicated that hydrothermal treatment had a significant influence on the composition and structure of the polysaccharides and lignin in the aqueous phase. The treatment could be adopted to obtain XOS-rich fraction with limited formation of by-products. In addition, the result was expected to further reveal the mechanisms of hydrothermal treatment on rapeseed straw and to facilitate the value-added applications of agricultural residues in the biorefinery industry. [ABSTRACT FROM AUTHOR]

A pair of reversible photochemical reactions correlates their reactant and product specifically, and such a correlation uniquely distinguishes their correlated signal from others that are not linked by this reversible reaction. Here a nanoparticle-shielded fluorophore is photodriven to undergo structural dynamics, alternating between a green-fluorescence state and a red-fluorescence state. As time elapses, the fluorophore can be in either state but not both at the same time. Thus, the red fluorescence is maximized while the green fluorescence is minimized and vice versa. Such an antiphase dual-color (AD) corelationship between the red and green fluorescence maxima as well as between their minima can be exploited to greatly improve the signal-to-noise ratio, thus enhancing the ultimate detection limit. Potential benefits of this correlation include elimination of all interferences originating from single-color dyes and signal amplification of AD photoswitching molecules by orders of magnitude. [ABSTRACT FROM AUTHOR]

Photosensitive fluorescent probes have become powerful tools in chemical biology and molecular biophysics, which are used to investigate cellular processes with high temporal and spatial resolution. Accordingly, photosensitive fluorescent probes, including photoactivatable, photoconvertible, and photoswitchable fluorophores, have been extensively developed during the past decade. The photoswitchable fluorophores have received much attention because they highlight cellular events clearly. This minireview summarizes recent advances of using reversibly photoswitchable fluorophores and their applications in innovative bioimaging. Photoswitchable fluorophores include photoswitchable fluorescent proteins, photoswitchable fluorescent organic molecules (dyes), and photoswitchable fluorescent nanoparticles. Several strategies have been developed to synthesize photoswitchable fluorophores, including engineering combination proteins, chemical synthesis, polymerization, and self-assembly. Here we concentrate on polymer nanoparticles with optically switchable emission properties: either fluorescence on/off or dual-alternating-color fluorescence photoswitching. The essential mechanisms of fluorescence photoswitching enable different types of photoswitchable fluorophores to change emission intensity or wavelength (color) and thus validating the basis of the fluorescence on/off or dual-color photoswitching design. Generally the possible applications of any fluorophores are to label biological targets, followed by specific imaging. The newly developed photoswitchable fluorophores enable super-resolution fluorescence imaging because of their photosensitive emission. Finally, we summarize the important area regarding future research and development on photoswitchable fluorescent nanoparticles. [ABSTRACT FROM AUTHOR]

Both photoswitchable fluorescent nanoparticles and photoactivatable fluorescent proteins have been used for super-resolution far-field imaging on the nanometer scale, but the photoactivating wavelength for such photochemical events generally falls in the near-UV (NUV) region (<420 nm), which is not preferred in cellular imaging. However, using two near-IR (NIR) photons that are lower in energy, we can circumvent such problems and replace NUV single-photon excitations (e.g., 390 nm) with NIR two-photon excitations (e.g., 780 nm). Thus, we have demonstrated that alternating 780 nm NIR two-photon and 488 nm single- photon excitations induces reversible on-off fluorescence switching of immunotargeted nanoparticles in the human breastcancercell line SK-BR-3. Herein, two-photon absorption notonlycaused spiropyran-merocyanine photoisomerization within the particles but also imparted red fluorescence. In comparison with single-photon NUV excitations, two-photon NIR laser excitations can potentially reduce absorption-related photodamage to living systems because cellular systems absorb much more weakly in the NIR. [ABSTRACT FROM AUTHOR]

Polymer nanoparticles of 40-400 nm diameter with spiropyran-merocyanine dyes incorporated into their hydrophobic cavities have been prepared; in contrast to their virtually nonfluorescent character in most environments, the merocyanine forms of the encapsulated dyes are highly fluorescent. Spiro-mero photoisomerization is reversible, allowing the fluorescence to be switched "on" and "off" by alternating UV and visible light. Immobilizing the dye inside hydrophobic pockets of nanoparticles also improves its photostability, rendering it more resistant than the same dyes in solution to fatigue effects arising from photochemical switching. The photophysical characteristics of the encapsulated fluorophores differ dramatically from those of the same species in solution, making nanoparticle-protected hydrophobic fluorophores attractive materials for potential applications such as optical data storage and switching and biological fluorescent labeling. To evaluate the potential for biological tagging, these optically addressable nanoparticles have been delivered into living cells and imaged with a liquid nitrogen-cooled CCD. [ABSTRACT FROM AUTHOR]

All-optical modulation of a spiropyran-based device, integrating the transmittance switching (absorption) and wavelength modulation (emission) of visible light frequency induced by alternating UV/visible light irradiation is demonstrated. As an alternative to conventional organic transistors, all-optical devices based on SP-PCL have potential utility as single molecular transistors for optical switching and visible wavelength modulation. [ABSTRACT FROM AUTHOR]

The article presents information on a hard-and-soft hybrid nanosystem whose fluorescence intensity can be reversibly modulated using specific bandwidths of light. There is considerable current interest within the rapidly expanding field of nanotechnology in integrating hard and soft structures into complex functional nanosystems that have stimuli responsive properties. The study specifically attaches a spiropyran via a thiol-metal linkage to a core-shell semiconductive CdSe/ZnS nanocrystal. Preparation of both the spiropyran and the core-shell nanocrystals is a straightforward procedures.

Super-resolution imaging has rapidly emerged as an optical microscopy technique, offering advantages of high optical resolution over the past two decades; achieving improved imaging resolution requires significant efforts in developing super-resolution imaging agents characterized by high brightness, high contrast and high sensitivity to fluorescence switching. Apart from technical requirements in optical systems and algorithms, super-resolution imaging relies on fluorescent dyes with special photophysical or photochemical properties. The concept of aggregation-induced emission (AIE) was proposed in 2001, coinciding with unprecedented advancements and innovations in super-resolution imaging technology. AIE probes offer many advantages, including high brightness in the aggregated state, low background signal, a larger Stokes shift, ultra-high photostability, and excellent biocompatibility, making them highly promising for applications in super-resolution imaging. In this review, we summarize the progress in implementation methods and provide insights into the mechanism of AIE-based super-resolution imaging, including fluorescence switching resulting from photochemically-converted aggregationinduced emission, electrostatically controlled aggregation-induced emission and specific bindingregulated aggregation-induced emission. Particularly, the aggregation-induced emission principle has been proposed to achieve spontaneous fluorescence switching, expanding the selection and application scenarios of super-resolution imaging probes. By combining the aggregation-induced emission principle and specific molecular design, we offer some comprehensive insights to facilitate the applications of AIEgens (AIE-active molecules) in super-resolution imaging. [ABSTRACT FROM AUTHOR]

The article presents information on a study which reveals that introduction of thermosensitive polymers on to gold nanoparticles become responsive to temperature. Poly(N-isopropylacrylamide) (PPA) exhibits a low critical solution temperature (LCST) transition from 30 to 45 degree Celsius. The polymer is hydrophilic and soluble in water below the LCST, but becomes hydrophobic and forms a macroscopic coacervate phase above that temperature due to the fluctuation of hydrophobic interactions and hydrogen bonding. Conjugation with gold nanoparticles requires that the polymer should bear a thiol group at one terminus. Using S-benzyl dithiobenzoate as the reversible addition-fragmentation chain transfer, researchers prepared a PPA homopolymer terminated with thioester groups. Gold nanoparticles coated with thiol-terminated PPA show remarkable temperature sensitivity as manifested in their optical transmittance switching property at 600 nm.

An abstract of the study "The Clinical and Molecular Genetic Study of 20 Silver Russell Syndrome Cases" by Chunxiu Gong et al is presented.

The article discusses the study investigating the reversibility photoswitchable dual-color fluorescent nanoparticles as new tools for live-cell imaging. According to the authors, fluorescent labeling of biomacromolecules and cells has become one of the major tools in the study of structural organization and intra- and intermolecular process within the biological systems.

Thecross-coupling reactions have been used in C–C bondformation which can be used extensively in optoelectronic materialsfor organic light-emitting diodes, organic photovoltaics, and chemicalbiosensing. Here, we report 2-fold geminal C–C bond formationat 1,1-dibromoolefins via cross-coupling reactions of aromatic boronicesters over Pd catalysts for multiple topological configurations ofπ-conjugated molecules. We employ a series of recipes from aprecursor toolbox to produce π-conjugated macrocycles, conjugateddendrimers, linear conjugated polymers, and multiple conjugated microporouspolymers and nanoparticles. The π-conjugated macrocycles, dendrimers,and linear polymers show characteristic aggregation-induced emissionproperties. The conjugated microporous polymers possess unique porosityof 2–3 nm. The microporous polymer nanoparticles can be redispersedin solution. This universal strategy toward definite topological configurationsof π-conjugated molecules enables efficient coupling of arylbromides with various coupling partners under mild conditions affordingmultiple topological conjugated systems with abundant optical andoptoelectronic interest. [ABSTRACT FROM AUTHOR]

One approach toward optical nanoimaging involves sequential molecular localization of photoswitchable fluorophores to achieve high resolution beyond optical limit of diffraction. Block copolymer micelles assembled from polystryrene-block-poly(ethylene oxide) block copolymers (PSt-b-PEO) are visualized in optical nanoimaging by staining the polystyrene blocks with spiropyrans (SPs). SPs localized in hydrophobic phase of block copolymer micelles exhibit reversible fluorescence on-off switching at alternating irradiation of UV and visible light. Phase-selective distribution of SPs in block copolymer micelles enables optical nanoimaging of microphase structures of block copolymer self-assembly at 50-nm resolution. To date, this is the sturdiest realization of optical nanoimaging with subdiffraction resolution for solution self-assembly of block copolymers. [ABSTRACT FROM AUTHOR]

Large-scale synthesis of semiconductor nanocrystals or quantum dots (QDs) with high concentration and high yield through simultaneously increasing the precursor concentration was introduced. This synthetic route conducted in diesel has produced gram-scale CdSe semiconductor quantum dots (In optimal scale-up synthetic condition, the one-pot yield of QDs is up to 9.6g). The reaction has been conducted in open air and at relatively low temperature at 190−230 °C in the absence of expensive organic phosphine ligands, aliphatic amine and octadecene, which is really green chemistry without high energy cost for high temperature reaction and unessential toxic chemicals except for Cd, which is the essential building block for QDs. [ABSTRACT FROM AUTHOR]

We demonstrate a novel synthetic approach to ortho-methyl substituted tetraphenylethene materials, which can be utilised for directly validating the restriction of intramolecular rotation hypothesis as the basic mechanism of aggregation-induced emission phenomenon and cell imaging. [ABSTRACT FROM AUTHOR]