JWZhang

Under the pumping of low power, continuous-wave (CW) 980 nm laser, upconverted microlasing spanning blue (450 nm), green (542 nm), red (654 nm) wavelength from Tm³⁺, Er³⁺, and Ho³⁺ doped nanoparticles can be observed when coupling with whispering galley mode (WGM) cavity. The ultralow threshold, stable microlasing is valuable for biosensing and imaging.

Abstract

The miniaturization of lasers holds promise in ultradense data storage and biosensing, but greater pump power is required to reach the lasing thresholds to overcome increased optical losses with reduced resonant cavity sizes. Here, the whispering galley mode (WGM) of Yb³⁺/Tm³⁺ doped upconversion nanoparticles (UCNPs) coupled with microcavities (≈5 µm) is used to achieve ultralow threshold upconverted lasing at 800 nm with excitation fluences as low as 4 W cm⁻². The continuous-wave (CW) upconverted lasing, with a Q factor on the order of 10³, can remain stable for more than 6 h. In addition, ultralow threshold upconverted microlasers spanning the full visible spectrum from Yb³⁺/Er³⁺, Yb³⁺/Ho³⁺, and Yb³⁺/Tm³⁺ doped UCNPs are obtained with the same WGM cavity design. These upconverted microlasers working under low power CW 980 nm laser will enable promising applications in biosensing and imaging.

Materials with tunable long persistent luminescence (LPL) properties have wide applications in security signs, anti‐counterfeiting, data encrypting and other fields, which have attracted great attention. However, the majority of reported tunable LPL materials are pure organic molecules or polymers. Herein, a series of metal‐organic coordination polymers displaying color‐tunable LPL were synthesized by the self‐assembly of HTzPTpy ligand with different cadmium halides (X = Cl, Br, and I). In solid state, their LPL emission colors can be tuned by the time‐evolution, as well as excitation and temperature variation, realizing multi‐mode dynamic color tuning from green to yellow or green to red, and representing the first example in single component coordination polymer materials. Single‐crystal X‐ray diffraction analysis and theoretical calculations reveal that the modification of LPL is due to the balanced action from single molecule and aggregate triplet excited states aroused by external heavy‐atom effect. The results suggest that the rational introduction of different halide anions into coordination polymers to realize multi‐color LPL is promising for different domain applications, including imaging, anti‐counterfeiting and security protection.

Lanthanide‐doped near‐infrared nanoparticles are emerging as a new class of optical probes for biological applications. A set of strategies to overcome the fundamental limits for enhanced luminescence brightness are presented, and their cutting‐edge biophotonic applications ranging from high spatiotemporal optical imaging to highly sensitive in vivo biosensing, and to light mediated synergistic therapy are highlighted.

Abstract

Light in the near‐infrared (NIR) spectral region is increasingly utilized in bioapplications, providing deeper penetration in biological tissues owing to the lower absorption and scattering in comparison with light in the visible range. Lanthanide‐doped luminescent nanoparticles with excitation and/or emission in the NIR range have recently attracted tremendous attention as one of the prime candidates for noninvasive biological applications due to their unique optical properties, such as large Stokes shift, spectrally sharp luminescence emissions, long luminescence lifetimes, and excellent photostability. Herein, recent advances of lanthanide‐doped nanoparticles with NIR upconversion or downshifting luminescence and their uses in cutting‐edge biophotonic applications are presented. A set of efficient strategies for overcoming the fundamental limit of low luminescence brightness of lanthanide‐doped nanoparticles is introduced. An in‐depth literature review of their state‐of‐art biophotonics applications is also included, showing their superiority for high‐resolution imaging, single‐nanoparticle‐level detection, and efficacy for tissue‐penetrating diagnostics and therapeutics.

US Navy personnel and local firefighters are battling a fire that broke out aboard amphibious assault ship USS Bonhomme Richard in San Diego, California, on July 12.

Fire department crews were called in at around 9:00 a.m. local time, after the fire broke out in the ship’s well deck.

The San Diego Fire Department also noted that an explosion had been heard, which could be the cause of the fire outbreak.

According to Naval Surface Forces, US Pacific Fleet, several sailors aboard the ship have been transported to the hospital for minor injuries. The navy added that the entire crew was off the ship and all accounted for.

The navy’s most recent statement said the fire started at around 8:30 a.m. with approximately 160 sailors aboard at the time. The statement added that 18 sailors had been transferred to a local hospital with non-life threatening injuries.

USS Bonhomme Richard was undergoing routine maintenance at the time of the incident.

USS Bonhomme Richard returned to San Diego in 2018, after spending six years forward-deployed to Japan. The ship was scheduled to undergo an upgrade that would allow it to operate F-35B STOVL fighter jets. The ship is expected to serve well into the 2030s, but it remains to be seen what will be the extent of the damages from the still blazing fire.

Photos of the fire aboard the ship circulating on social media appear to show the recently-repaired destroyer USS Fitzgerald, which had been heavily damaged in a collision in 2017.

The post Sailors injured in fire aboard US amphibious assault ship Bonhomme Richard appeared first on Defense Brief.

Protein 4 ' ‐ phosphopantetheinylation is an essential post‐translational modification (PTM) in prokaryotes and eukaryotes. So far, only five protein substrates of this specific PTM have been discovered in mammalian cells. These proteins are known to perform important functions including fatty acid biosynthesis and folate metabolism, as well as β ‐alanine activation. In order to explore existing and new substrates of 4 ' ‐ phosphopantetheinylation in mammalian proteomes, we designed and synthesized a series of new pantetheine analogue probes enabling effective metabolic labelling of 4 ' ‐ phosphopantetheinylated proteins in HepG2 cells . In combination with a quantitative chemical proteomic platform, we enriched and identified all the currently known 4 ' ‐ phosphopantetheinylated proteins with high confidence, and unambiguously determined their exact sites of modification. More encouragingly, we discovered, via targeted proteomics , a potential 4 ' ‐ phosphopantetheinylated site in the protein of mitochondrial dehydrogenase/reductase SDR family member 2 (DHRS2).

A tumor‐microenvironment‐responsive lanthanide–cyanine Förster resonance energy transfer nanosensor is designed for lifetime‐based hepatocellular carcinoma in situ detection in the second near‐infrared window (1000–1700 nm). Given lifetime measurement is immune to a constant background from ambient light, augmented reality can be integrated to enable a wide range of preclinical biomedical applications.

Abstract

Deep tissue imaging in the second near‐infrared (NIR‐II) window holds great promise for widespread fundamental research. However, inhomogeneous signal attenuation due to tissue absorption and scattering hampers its application for accurate in vivo biosensing. Here, lifetime‐based in situ hepatocellular carcinoma (HCC) detection in NIR‐II region is presented using a tumor‐microenvironment (peroxynitrite, ONOO⁻)‐responsive lanthanide–cyanine Förster resonance energy transfer (FRET) nanosensor. A specially designed ONOO⁻‐responsive NIR‐II dye, MY‐1057, is synthesized as the FRET acceptor. Robust lifetime sensing is demonstrated to be independent of tissue penetration depth. Tumor lesions are accurately distinguished from normal tissue due to the recovery lifetime. Magnetic resonance imaging and liver dissection results illustrate the reliability of lifetime‐based detection in single and multiple HCC models. Moreover, the ONOO⁻ amount can be calculated according to the standard curve.

An aggregation‐induced emission photosensitizer (TQ‐BTPE) with good two‐photon absorption and high singlet oxygen generation is synthesized for NIR‐II light (1200 nm) activated two‐photon photodynamic therapy, which exhibits better tissue penetration and more precise cancer cell ablation than NIR‐I light.

Abstract

Near infrared (NIR) light excitable photosensitizers are highly desirable for photodynamic therapy with deep penetration. Herein, a NIR‐II light (1200 nm) activated photosensitizer TQ‐BTPE is designed with aggregation‐induced singlet oxygen (¹O₂) generation for two‐photon photodynamic cancer cell ablation. TQ‐BTPE shows good two‐photon absorption and bright aggregation‐induced NIR‐I emission upon NIR‐II laser excitation. The ¹O₂ produced by TQ‐BTPE in an aqueous medium is much more efficient than that of commercial photosensitizer Ce6 under white light irradiation. Upon NIR‐II excitation, the two‐photon photosensitization of TQ‐BTPE is sevenfold higher than that of Ce6. The TQ‐BTPE molecules internalized by HeLa cells are mostly located in lysosomes as small aggregate dots with homogeneous distribution inside the cells, which favors efficient photodynamic cell ablation. The two‐photon photosensitization of TQ‐BTPE upon NIR‐I and NIR‐II excitation shows higher ¹O₂ generation efficiency than under NIR‐I excitation owing to the larger two‐photon absorption cross section at 920 nm. However, NIR‐II light exhibits better biological tissue penetration capability after passing through a fresh pork tissue, which facilitates stronger two‐photon photosensitization and better cancer cell ablation performance. This work highlights the promise of NIR‐II light excitable photosensitizers for deep‐tissue photodynamic therapy.

Control over the self‐assembly of colloidal semiconductor nanocrystals, known as quantum dots (QDs), is a great challenge. In this Minireview, the self‐assemblies of QDs with organic template molecules are highlighted (see figure), which should facilitate future advances in materials science related to assembled QDs.

Abstract

Colloidal semiconductor nanocrystals, known as quantum dots (QDs), are regarded as brightly photoluminescent nanomaterials possessing outstanding photophysical properties, such as high photodurability and tunable absorption and emission wavelengths. Therefore, QDs have great potential for a wide range of applications, such as in photoluminescent materials, biosensors and photovoltaic devices. Since the development of synthetic methods for accessing high‐quality QDs with uniform morphology and size, various types of QDs have been designed and synthesized, and their photophysical properties dispersed in solutions and at the single QD level have been reported in detail. In contrast to dispersed QDs, the photophysical properties of assembled QDs have not been revealed, although the structures of the self‐assemblies are closely related to the device performance of the solid‐state QDs. Therefore, creating and controlling the self‐assembly of QDs into well‐defined nanostructures is crucial but remains challenging. In this Minireview, we discuss the notable examples of assembled QDs such as dimers, trimers and extended QD assemblies achieved using organic templates. This Minireview should facilitate future advancements in materials science related to the assembled QDs.

Fully autonomous colloidal synthesis studies implementing a self‐driving microfluidic platform with machine‐learning‐based experiment selection achieve unassisted material exploration. Halide‐exchanged cesium lead bromide quantum dots are optimized simultaneously for photoluminescence quantum yield, polydispersity, and peak emission energy, independent of user intervention. Eleven target emissions are reached within 30 h and 210 mL of starting quantum dots and without prior knowledge.

Abstract

The optimal synthesis of advanced nanomaterials with numerous reaction parameters, stages, and routes, poses one of the most complex challenges of modern colloidal science, and current strategies often fail to meet the demands of these combinatorially large systems. In response, an Artificial Chemist is presented: the integration of machine‐learning‐based experiment selection and high‐efficiency autonomous flow chemistry. With the self‐driving Artificial Chemist, made‐to‐measure inorganic perovskite quantum dots (QDs) in flow are autonomously synthesized, and their quantum yield and composition polydispersity at target bandgaps, spanning 1.9 to 2.9 eV, are simultaneously tuned. Utilizing the Artificial Chemist, eleven precision‐tailored QD synthesis compositions are obtained without any prior knowledge, within 30 h, using less than 210 mL of total starting QD solutions, and without user selection of experiments. Using the knowledge generated from these studies, the Artificial Chemist is pre‐trained to use a new batch of precursors and further accelerate the synthetic path discovery of QD compositions, by at least twofold. The knowledge‐transfer strategy further enhances the optoelectronic properties of the in‐flow synthesized QDs (within the same resources as the no‐prior‐knowledge experiments) and mitigates the issues of batch‐to‐batch precursor variability, resulting in QDs averaging within 1 meV from their target peak emission energy.