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Purpose: To improve image quality, mitigate quantification biases and variations for free‐breathing liver proton density fat fraction (PDFF) and R2*$$ {\mathrm{R}}_2^{\ast } $$ quantification accelerated by radial k‐space undersampling. Methods: A free‐breathing multi‐echo stack‐of‐radial MRI method was developed with compressed sensing with multidimensional regularization. It was validated in motion phantoms with reference acquisitions without motion and in 11 subjects (6 patients with nonalcoholic fatty liver disease) with reference breath‐hold Cartesian acquisitions. Images, PDFF, and R2*$$ {\mathrm{R}}_2^{\ast } $$ maps were reconstructed using different radial view k‐space sampling factors and reconstruction settings. Results were compared with reference‐standard results using Bland–Altman analysis. Using linear mixed‐effects model fitting (p < 0.05 considered significant), mean and SD were evaluated for biases and variations of PDFF and R2*$$ {\mathrm{R}}_2^{\ast } $$, respectively, and coefficient of variation on the first echo image was evaluated as a surrogate for image quality. Results: Using the empirically determined optimal sampling factor of 0.25 in the accelerated in vivo protocols, mean differences and limits of agreement for the proposed method were [−0.5; −33.6, 32.7] s−1 for R2*$$ {\mathrm{R}}_2^{\ast } $$ and [−1.0%; −5.8%, 3.8%] for PDFF, close to those of a previous self‐gating method using fully sampled radial views: [−0.1; −27.1, 27.0] s−1 for R2*$$ {\mathrm{R}}_2^{\ast } $$ and [−0.4%; −4.5%, 3.7%] for PDFF. The proposed method had significantly lower coefficient of variation than other methods (p < 0.001). Effective acquisition time of 64 s or 59 s was achieved, compared with 171 s or 153 s for two baseline protocols with different radial views corresponding to sampling factor of 1.0. Conclusion: This proposed method may allow accelerated free‐breathing liver PDFF and R2*$$ {\mathrm{R}}_2^{\ast } $$ mapping with reduced biases and variations. [ABSTRACT FROM AUTHOR]

Hypokalemia and hyponatremia are common but easily ignored adverse events in treatment with voriconazole (VCZ) that can lead to serious consequences. We intend to investigate the incidence of VCZ‐induced hypokalemia and hyponatremia and their risk factors based on real‐world data. A prospective study was conducted. A total of 272 patients with 414 VCZ plasma trough concentrations (C0) and VCZ N‐oxide concentrations (CN) were included. The incidence of hypokalemia was 18.0% (48/266). A total of 81.2% (39/48) of patients developed hypokalemia within 14 days, whereas 56.2% (27/48) of patients developed hypokalemia within 1 week. The proportion of female patients in the hypokalemia group was higher than that in the nonhypokalemia group, as was the proportion of patients receiving intravenous VCZ. In the multivariate analysis, the independent risk factors for hypokalemia were sex, combined use of antibiotics, and VCZ CN/C0. The incidence of hyponatremia was 7.9% (21/266). The proportion of patients over 47 years of age in the hyponatremia group was 71.4% (15/21). The number of days of VCZ use in the hyponatremia group was greater than that in the nonhyponatremia group. A total of 47.6% (10/21) of patients in the hyponatremia group had supratherapeutic VCZ C0 (>5.0 µg/mL). In conclusion, hypokalemia is more likely to occur in females, in patients receiving intravenous VCZ, and in patients with the combined use of antibiotics. Hyponatremia is more likely to occur in patients older than 47 years who have been using VCZ for a long time and have higher VCZ C0 values. [ABSTRACT FROM AUTHOR]

5‐Formylcytosine (f5C) modification is present in human mitochondrial methionine tRNA (mt‐tRNAMet) and cytosolic leucine tRNA (ct‐tRNALeu), with their formation mediated by NSUN3 and ALKBH1. f5C has also been detected in yeast mRNA and human tRNA, but its transcriptome‐wide distribution in mammals has not been studied. Here we report f5C‐seq, a quantitative sequencing method to map f5C transcriptome‐wide in HeLa and mouse embryonic stem cells (mESCs). We show that f5C in RNA can be reduced to dihydrouracil (DHU) by pic‐borane, and DHU can be exclusively read as T during reverse transcription (RT) reaction, allowing the detection and quantification of f5C sites by a unique C‐to‐T mutation signature. We validated f5C‐seq by identifying and quantifying the two known f5C sites in tRNA, in which the f5C modification fractions dropped significantly in ALKBH1‐depleted cells. By applying f5C‐seq to chromatin‐associated RNA (caRNA), we identified several highly modified f5C sites in HeLa and mouse embryonic stem cells (mESC). [ABSTRACT FROM AUTHOR]

Photothermal applications, such as therapy, imaging, and catalysis, necessitate heat sources capable of generating high temperatures under mid‐infrared (mid‐IR) illumination. However, commonly used metal nanostructures suffer from low efficiency due to their high carrier concentrations, resulting in shallow surface heating and optical range restrictions. To overcome these limitations, this work proposes a novel approach employing materials that support phonon polaritons (PhPs) as a promising paradigm for light‐controllable heat sources. The theoretical demonstration reveals that hexagonal boron nitride (hBN) nanorods can produce up to 46 times more heat compared to plasmonic gold counterparts under resonant monochromatic light. This superior heating capability stems from the unique properties of PhPs, which enable stronger field confinement and deeper penetration within the nanostructure, leading to higher efficiency by circumventing the electrostatic shielding effect associated with plasmonic heating. Furthermore, this work demonstrates that the heating performance of hBN antennas can be optimized by manipulating their size, geometry, and material loss. Notably, the use of isotopically pure hBN can triple the heat power. These findings highlight the tremendous potential of hBN antennas as light‐controllable heat sources, opening up new possibilities for IR photothermal applications by harnessing materials that support PhPs. [ABSTRACT FROM AUTHOR]

We report a highly enhanced light extraction from a top emission organic light emitting diode with little image blurring. Integration of a high refractive index micro lens array on the top of the transparent indium zinc oxide top electrode of a green and blue OLED shows a significant EQE gain of 16% and 8%, respectively. [ABSTRACT FROM AUTHOR]

The activation of water molecules in thermal catalysis typically requires high temperatures, representing an obstacle to catalyst development for the low‐temperature water‐gas shift reaction (WGSR). Plasmonic photocatalysis allows activation of water at low temperatures through the generation of light‐induced hot electrons. Herein, we report a layered double hydroxide‐derived copper catalyst (LD‐Cu) with outstanding performance for the low‐temperature photo‐driven WGSR. LD‐Cu offered a lower activation energy for WGSR to H2 under UV/Vis irradiation (1.4 W cm−2) compared to under dark conditions. Detailed experimental studies revealed that highly dispersed Cu nanoparticles created an abundance of hot electrons during light absorption, which promoted *H2O dissociation and *H combination via a carboxyl pathway, leading to the efficient production of H2. Results demonstrate the benefits of exploiting plasmonic phenomena in the development of photo‐driven low‐temperature WGSR catalysts. [ABSTRACT FROM AUTHOR]

Quasi‐two‐dimensional (quasi‐2D) organic–inorganic hybrid perovskites have shown excellent ambient stability with decent photovoltaic performance. Further improvement of device level properties requires a comprehensive understanding of the performance‐limiting mechanisms such as phase segregation, ion/electron coupling conduction, and their effects on charge transport at both the micro‐ and macro‐scale. Here, space resolved investigations of Ruddlesden–Popper (RP) phases of the commonquasi‐2D perovskite are probed using two complementary methods, conducting atomic force microscopy (c‐AFM) and Kelvin probe force microscopy (KPFM). Bias‐driven photocurrent mappings obtained by c‐AFM measurements disclose local inhomogeneous conduction and hysteresis currents in quasi‐2D RP perovskites, while relatively uniform conductivity is observed on individual grains. Bias‐driven KPFM reveals that the surface average photovoltage sign is dominated by the band bending at the buried perovskite–substrate interface. The quasi‐2D RP film exhibits substantial variations in the spatial response of the photovoltage across grains and grain boundaries, which is direct evidence of the inherently benign nature of microstructures, and the final device performance. This research elucidates underlying space‐resolved photoresponse mechanisms behind the lower efficiency of quasi‐2D RP perovskites compared with the 3D perovskites, which is necessary for further development of efficient and stable 2D perovskite‐based devices. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) with carbon dioxide to produce syngas is currently attracting a lot of attention for converting greenhouse gases into valuable chemicals. However, harsh reaction conditions in thermal catalysis hinder practical applications. Herein, a series of alumina‐supported NixFey nanoalloys are synthesized from NiFeAl‐layered double hydroxide precursors, with the obtained catalysts used for photothermal synergistic DRM. The Ni3Fe1 nanoalloy catalyst shows a syngas production rate of 0.96 mol g–1 h–1 under a 350 °C photothermal condition, which is about 1100 times higher than that of the same catalyst at the same temperature in the dark. Methane activation as the rate‐determining step in DRM is greatly enhanced by the localized surface plasmon resonance of the Ni3Fe1 nanoalloy in the ultraviolet region, thus accounting for the remarkably reduced reaction temperature. Meanwhile, the nanoalloy‐based photothermal synergistic DRM exhibits sunlight‐driven feasibility and 20 h of continuous operational stability. [ABSTRACT FROM AUTHOR]

Optical‐field driven electron tunneling in nanojunctions has made demonstrable progress toward the development of ultrafast charge transport devices at subfemtosecond time scales, and have evidenced great potential as a springboard technology for the next generation of on‐chip "lightwave electronics." Here, the empirical findings on photocurrent the high nonlinearity in metal–insulator–metal (MIM) nanojunctions driven by ultrafast optical pulses in the strong optical‐field regime are reported. In the present MIM device, a 14th power‐law scaling is identified, never achieved before in any known solid‐state device. This work lays important technological foundations for the development of a new generation of ultracompact and ultrafast electronics devices that operate with suboptical‐cycle response times. [ABSTRACT FROM AUTHOR]

Objectives: As a rare malformation of the female reproductive system, Herlyn‐Werner‐Wunderlich syndrome (HWWS) was categorized into 3 classifications. It was recommended recently that, on the basis of the past classification, cervicovaginal atresia without communicating uteri should be newly added as classification 4. The surgical intervention will differ by type. To better optimize patient counseling as well as the preoperative evaluation and planning, our objective was to describe the ultrasound characteristics of each type of HWWS, including the new type. Methods: From January 1995 to November 2015, 37 cases of HWWS in with complete ultrasound information confirmed by surgery in the Peking Union Medical College Hospital were reviewed. We analyzed their ultrasound features, including hematometra, hematocervix, hematocolpos, and an ovarian chocolate cyst. Results: All of the ultrasound images of the 37 patients showed uterus didelphys with ipsilateral renal agenesis. Compared with the other 3 types, classification 4 showed distinctive ultrasound characteristics. Most cases of classification 4 showed hematometra (5 of 7 [71.4%]) and an ipsilateral ovarian chocolate cyst (6 of 7 [85.7%]), which was significantly higher than in the other 3. A rudimentary uterine horn was also a distinctive characteristic in this type. Meanwhile none of the classification 4 cases showed hematocervix or hydrocolpos, which were common signs of the other 3. Conclusions: According to this new classification criteria for HWWS, ultrasound characteristics of the new classification 4 differ from the others. As classification 4 was suggested to have a different surgical option, we should pay attention to its ultrasound characteristics, which might help in providing more information about the treatment and prognosis to the gynecologist. Access the CME test here and search by article title. [ABSTRACT FROM AUTHOR]

Smart wearable devices have made remarkable success in medical‐grade human vital signal monitoring and have promoted the realization of precision medicine and telemedicine. The flexibility and stretchability are significant for wearable devices, which determine the adhesion to the skin and influence the signal accuracy. Here, a stretchable and ultrathin optical sensor based on a self‐assembled wavy microfiber is proposed. Thanks to the "bottom–up" strategy, the wave structure of the microfiber can be adjusted artificially, paving the way for the design of stretchable optical devices. Due to the microbend loss of the microfiber, the optical sensor has a sensitivity of ≈257 per unit strain and a good repetition (the standard deviation is 1.7% over 100 cycles). With the great sensor performance, the wrist pulse with a high signal‐to‐noise ratio is detected and the blood pressure is monitored successfully via the pulse arrival time, showing a potential application for human health monitoring. [ABSTRACT FROM AUTHOR]

Asymmetric construction of pharmacologically interesting tetrahydrofuranyl spirooxindole frameworks has been achieved through organocatalytic [3+2] annulations of the readily available 3‐hydroxyoxindoles and pyrrolidone‐derived cyclic ketolactams. A variety of chiral spiro tetrahydrofuranyl products, which contain four contiguous stereocenters including two tetrasubstituted carbon centers, have been rapidly synthesized with remarkable results (up to 99% yield, >95:5 dr, and 99:1 er). Synthetic derivatization of the hemiketal moiety enables the installation of various halogen atoms into the structurally complex molecules in a stereospecific manner. Preliminary screening of anticancer bioactivity was performed, and 4 w showed obvious inhibitory capacity to the proliferation on a panel of cancer cell lines. [ABSTRACT FROM AUTHOR]

Membranes with precise control of selective layer are designed and prepared by adjusting diffusion of solvents. Combining experiments and theoretical calculations, the formation mechanism of ion conductive membranes prepared by a non‐solvent induced phase separation (NIPS) method is found to be related to internal diffusion flux of solvent to the non‐solvent bath and external diffusion flux of non‐solvent to the casting solution. By regulating the internal and external diffusion rates via a two‐step NIPS method, a series of polybenzimidazole (PBI) porous membranes with independently controlled thin selective skin layers and highly porous support layers are fabricated, which achieve a simultaneous improvement in ion selectivity and proton conductivity. A vanadium flow battery assembled with a PBI membrane demonstrates an energy efficiency of 80% at a current density of 220 mA cm−2, which is the highest value among the reported PBI membranes. This provides a simple and effective way to fabricate membranes with well‐defined morphologies. [ABSTRACT FROM AUTHOR]

Flow batteries (FBs) are one of the most attractive candidates for stationary energy storage and vital in realizing the wide application of renewable energies. Membranes play an important role in isolating redox couples while transporting ions to close the internal electrical circuit. Therefore, membranes with high selectivity and conductivity are highly important. Among different membranes, a composite membrane with independent design of support layer and thin selective top layer becomes one of the most promising candidates to break the trade‐off between selectivity and conductivity. In this Review, recent studies on composite membranes for FBs and the principles of membrane design in different systems are discussed and summarized. Finally, the future direction on membrane design for different FBs is presented, which will provide an extensive, comprehensive reference to design and construct high‐performance composite membranes for FBs. [ABSTRACT FROM AUTHOR]

In this paper we introduce a thermally evaporated optical regulating layer (ORL) to adjust the optical cavity length of solution top‐emission devices. ORL has high conductivity in the thickness range up to 1500 Å, which can meet the requirements of large‐sized printing OLED product process. Interface improvement layer (IIL) is further introduced to improve the carrier injection and enhance efficiency. Compared with the bottom device, the efficiency of optimized device increases by 2.0 times, while the voltage does not increase. Compared with the traditional solution top‐emission device, which has a narrow process window, the efficiency of optimized device increases by 15% and the voltage decreases by 0.8 V. [ABSTRACT FROM AUTHOR]

Polaritons in 2D materials exhibit extensive optical phenomena, such as an ultrahigh field confinement and tunability and, thus, have been attracting increasing attentions. Many different methods have been developed to characterize and manipulate polaritons, which in turn has promoted a steady booming of this field. Here, the significant progress made in probing polaritons in 2D materials based on the characterization method, i.e., optical far‐field, optical near‐field, and (opto)electronic methods is reviewed. Perspectives on the potential development and applications of these methods are also discussed. [ABSTRACT FROM AUTHOR]

The development of electronics and photonics is entering a new era of ultrahigh speed sensing, data processing, and telecommunication. The carrier frequencies of the next‐generation electronic devices inevitably extend beyond radio frequencies, marching toward the nominally photonics‐dominated territories, e.g., terahertz and beyond. As a result, electronic and photonic techniques naturally merge and seek common ground. At the forefront of this technical trend is the field of polaritonics, where polaritons are half‐light, half‐matter quasiparticles that carry the properties of both "bare" photons and "bare" dipole‐carrying excitations. The Janus‐faced nature of polaritons renders the unique capability of operando control using photoexcitation or applied electric field. Here, state‐of‐the‐art ultrafast polaritonic phenomena probed by scattering‐type scanning near‐field optical microscope (s‐SNOM) techniques is reviewed. The ultrafast dynamical control and loss‐reduction of the polariton propagation are discussed with special emphasis on the creation and probing of the tip or edge induced plasmon– and phonon–polaritons in low‐dimensional systems. The detailed technical aspects of s‐SNOM and its possible future development are also presented. [ABSTRACT FROM AUTHOR]

Infrared (IR) phototransistors are important building blocks for the true integration of flat‐panel optoelectronic detectors. Although significant progress is made in obtaining an InGaZnO active layer with IR response, the utilization of a high‐performance detector still has many challenges due to low efficiency, high power consumption, and lagging detection speed. Herein, a positive‐intrinsic‐negative (PIN) heterostructure phototransistor directly modulating the charges' transfer barrier with low power consumption (1 nW), high efficiency (EQE > 700%), a 200 Hz detecting bandwidth, and high detectivity (1 × 1011 cm Hz1/2 W−1) at an IR wavelength (1.5 µm in the high‐frequency circumstance) is demonstrated. These excellent sensing properties of the PIN phototransistor, together with its advantages of low power consumption and versatility, make the use of a heterostructure a powerful strategy for the development of on‐chip optoelectronic detectors. [ABSTRACT FROM AUTHOR]

An efficient diastereo‐ and enantioselective formal oxo‐Diels‐Alder reaction of enolizable aliphatic aldehydes and 5‐alkenyl thiazolones was developed through chiral amine catalysis. With a robust enamine activation strategy, both simple aliphatic aldehydes and a challenging aqueous acetaldehyde could participate well as competent dienophiles in the reaction. A variety of thiazole‐fused dihydropyran derivatives were facilely produced in up to 99% yield with up to >99:1 e.r. under mild conditions. Interestingly, a high dosage of the inexpensive aqueous acetaldehyde in a similar catalytic system could lead to a densely functionalized thiazolone product through a three‐component cascade reaction, suggesting a step‐wise mechanism for the established [4+2] annulation process. [ABSTRACT FROM AUTHOR]

Catalyst and solvent‐free reactions have attracted great attention from chemists because of their inherent advantages that coincide with the principles of sustainable chemistry and the increasing public awareness of environmental protection. Here, we disclose the first catalyst‐free intermolecular cyclopropanation of phenyliodonium ylides with electron‐deficient alkenes. Full conversion can be achieved at ambient temperature, in the absence of any catalyst, within a short reaction time. Importantly, such reactions work reasonably well in water or even under solvent‐free conditions, which enables a green, convenient and efficient way to synthesize valuable multifunctional vinylcyclopropanes. Clean and efficient! A catalyst‐free intermolecular cyclopropanation between phenyliodonium ylides and electron‐deficient olefins has been developed, which could be completed generally within 5 minutes without the use of any metal or organic catalyst. In addition, this reaction works quite well in water or even under solvent‐free conditions, which enables a green, convenient and efficient way to synthesize a range of valuable vinylcyclopropanes with different substituents and functionalities. [ABSTRACT FROM AUTHOR]

Abstract: Flexible plasmonic devices with electrical tunability are of great interest for diverse applications, such as flexible metamaterials, waveguide transformation optics, and wearable sensors. However, the traditional flexible metal–polymer plasmonic structures suffer from a lack of electrical tunability. Here the first flexible, electrically tunable, and strain‐independent plasmons based on graphene–mica heterostructures are experimentally demonstrated. The resonance frequency, strength, quality factor, electrical tunability, and lifetime of graphene plasmons exhibit no visible change at bending radius down to 1 mm and after 1000 bending cycles at a radius of 3 mm. The plasmon‐enhanced infrared spectroscopy detection of chemicals is also demonstrated to be unaffected in the flexible graphene–mica heterostructures. The results provide the basis for the design of flexible active nanophotonic devices such as plasmonic waveguides, resonators, sensors, and modulators. [ABSTRACT FROM AUTHOR]

Abstract: Actively mode‐locked lasers offer varying degrees of flexibility for a wider range of applications than their passively modulated counterparts, due to their capability for electrically controlled ultrahigh repetition rate operation. Graphene based electrooptic modulators with unique advantages of broad operation bandwidth and ultrafast speed are suitable for light modulation in various optoelectronic applications. Here, an actively mode‐locked laser with a graphene based electrooptic modulator is reported for the first time. The active mode‐locking technique combined together with the intracavity nonlinear pulse shortening effect allows the generation of transform‐limited 1.44 ps pulses with pulse energy of 844 pJ. The electrically controlled repetition rate of generated pulses, a key performance advantage of active mode‐locking, is also demonstrated. These results provide a practical and effective approach for actively mode‐locked lasers with broad operation bandwidth and compact footprint, which contributes a new way for applications of two‐dimensional (2D) layered materials in ultrafast lasers. [ABSTRACT FROM AUTHOR]

Abstract: Dynamic structural coloration in Tmesisternus isabellae beetle elytra is a unique example of Bragg stack‐based wavelength tuning in response to external stimuli. The underlying principles could guide the design of quantitative optical stimuli‐responsive polymers. Existing nanofabrication techniques to create such materials are costly, time‐consuming, and require high expertise. This study reports a nanofabrication method to produce slanted Bragg stack structures in poly(acrylamide‐co‐poly(ethylene glycol) diacrylate) hydrogel films by combining laser interference lithography and silver halide chemistry in a cost‐effective and rapid process (≈10 min). The Bragg stacks consist of silver bromide nanocrystal multilayers having a lattice spacing of ≈200 nm. Upon broadband light illumination, the Bragg stacks diffract a narrow‐band peak at 520 nm at ≈10° with respect to the normal incidence. The lattice spacing of the hydrogel films can be modulated by external stimuli to shift the Bragg peak for dynamic quantitative measurements. To demonstrate the utility of this method, the Bragg stacks are functionalized with phenylboronic acid molecules. Bragg peak shift analysis allows reversible glucose sensing within a physiological dynamic range (0.0–20.0 mmol L−1) having a sensitivity of 0.2 mmol L−1. The developed Bragg stacks may have application in portable, wearable, and implantable real‐time medical diagnostics at point‐of‐care settings. [ABSTRACT FROM AUTHOR]

Abstract: The Nicobar pigeon (Caloenas Nicobarica) belongs to the extinct dodo‐bird family and has been declared as an endangered species. Here, microscopic and spectroscopic measurements are carried out on the bird's feathers to study the structural coloration originating from the barbule nanostructures. A range of color shades is recorded with changing viewing and illumination angles at different locations of the feathers. A spectacular variation in colors is generated by photonic structures; red, green, and blue and their blends are observed. Hydrophobicity of the optical material is also investigated. A contact angle of ≈156° is observed demonstrating it to be superhydrophobic. Experimental observations of the optical properties are analyzed on these feathers for sensing made possible due to the material and structural properties at the interface between barbule's surface and solution. An optical response is observed with a redshift in optical spectra with increasing refractive index of the solution, which is correlated with concentration values. The structural coloration in Nicobar pigeon can be adopted for many practical applications such as color selective filters, nonreflecting coatings, and refractive index‐based sensing. [ABSTRACT FROM AUTHOR]

Abstract: Asymmetric construction of halogenated quaternary carbon centers under mild reaction conditions remains challenging. Reported here is an unprecedented and highly stereoselective Brønsted base catalyzed [4+2] cycloaddition between either α‐chloro‐ or α‐bromoaldehydes and cyclic enones. The key intermediate, an α‐halogenated enolate, is susceptible to dehalogenation and can be stabilized and stereochemically controlled using bifunctional tertiary amines. This method provides facile access to a collection of optically pure bicyclic dihydropyrans having three contiguous stereocenters, including a halogen‐bearing quaternary carbon center. Of note, the product can be transformed in situ into densely functionalized spirocyclopropanes in a highly efficient and stereoselective manner. [ABSTRACT FROM AUTHOR]

Abstract: Here we report a secondary amine‐catalyzed, highly enantioselective [3+3] cyclization reaction of α‐alkylidene pyrazolinones and α,β‐unsaturated aldehydes, which facilely delivers a variety of enantioenriched spiropyrazolones showing structural and stereochemical complexity. The reaction uses an iminium ion activation strategy to activate both the β‐ and ipso‐positions of the enals as dielectrophilic sites. A broad range of substrates are compatible with this mild reaction system. [ABSTRACT FROM AUTHOR]

The abundant Watson-Crick face methylations in biological RNAs such as N1-methyladenosine (m1A), N1-methylguanosine (m1G), N3-methylcytosine (m3C), and N2,N2-dimethylguanosine (m22G) cause significant obstacles for high-throughput RNA sequencing by impairing cDNA synthesis. One strategy to overcome this obstacle is to remove the methyl group on these modified bases prior to cDNA synthesis using enzymes. The wild-type E. coli AlkB and its D135S mutant can remove most of m1A, m1G, m3C modifications in transfer RNA (tRNA), but they work poorly on m22G. Here we report the design and evaluation of a series of AlkB mutants against m22G-containing model RNA substrates that we synthesize using an improved synthetic method. We show that the AlkB D135S/L118V mutant efficiently and selectively converts m22G modification to N2-methylguanosine (m2G). We also show that this new enzyme improves the efficiency of tRNA sequencing. [ABSTRACT FROM AUTHOR]

Fluorescence imaging is a promising tool for the visualization of biomolecules in living systems and there is great demand for new fluorescent dyes that absorb and emit in the near-infrared (NIR) region. Herein, we constructed three new fluorescent dyes ( NBC dyes) based on keto-benzo[ h]coumarin ( k-BC) and benzopyrilium salts. These dyes showed large Stokes shifts (>100 nm) and NIR emission (>800 nm). The relationship between the structures and optical properties of these dyes was further investigated by using density functional theory calculations at the B3LYP/6-3G level of theory. Fluorescence images indicated that the fabricated dyes exhibited good photostability and low cytotoxicity and, thus, have potential applications as imaging agents in living cells and animals. [ABSTRACT FROM AUTHOR]