Fibrillar centers (FCs) and dense fibrillar components (DFCs) are essential morphologically distinct sub-regions of mammalian cell nucleoli for rDNA transcription and pre-rRNA processing. Here, we ...report that a human nucleolus consists of several dozen FC/DFC units, each containing 2–3 transcriptionally active rDNAs at the FC/DFC border. Pre-rRNA processing factors, such as fibrillarin (FBL), form 18–24 clusters that further assemble into the DFC surrounding the FC. Mechanistically, the 5′ end of nascent 47S pre-rRNA binds co-transcriptionally to the RNA-binding domain of FBL. FBL diffuses to the DFC, where local self-association via its glycine- and arginine-rich (GAR) domain forms phase-separated clusters to immobilize FBL-interacting pre-rRNA, thus promoting directional traffic of nascent pre-rRNA while facilitating pre-rRNA processing and DFC formation. These results unveil FC/DFC ultrastructures in nucleoli and suggest a conceptual framework for considering nascent RNA sorting using multivalent interactions of their binding proteins.
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•Visualizing the ultrastructure of FC/DFC and rDNA arrangements in human nucleoli•Processing factors, such as FBL, form protein clusters and then assemble into a DFC•Self-association of GAR in FBL ensures sorting and processing of nascent 47S pre-rRNA•Nascent pre-rRNA sorting via a phase-separation mechanism promotes DFC assembly
Yao et al. unveil the FC/DFC ultrastructure and rDNA arrangements in human nucleoli and show that a phase-separation mechanism promotes nascent pre-rRNA sorting and processing and the assembly of the DFC sub-nucleolar region.
Low thermal conductivity is favorable for preserving the temperature gradient between the two ends of a thermoelectric material, in order to ensure continuous electron current generation. In ...high-performance thermoelectric materials, there are two main low thermal conductivity mechanisms: the phonon anharmonic in PbTe and SnSe, and phonon scattering resulting from the dynamic disorder in AgCrSe
and CuCrSe
, which have been successfully revealed by inelastic neutron scattering. Using neutron scattering and ab initio calculations, we report here a mechanism of static local structure distortion combined with phonon-anharmonic-induced ultralow lattice thermal conductivity in α-MgAgSb. Since the transverse acoustic phonons are almost fully scattered by the compound's intrinsic distorted rocksalt sublattice, the heat is mainly transported by the longitudinal acoustic phonons. The ultralow thermal conductivity in α-MgAgSb is attributed to its atomic dynamics being altered by the structure distortion, which presents a possible microscopic route to enhance the performance of similar thermoelectric materials.
Reliable and noninvasive biomarkers for the early diagnosis of non‐small‐cell lung cancer (NSCLC) are an unmet need. This study aimed to screen and validate potential urinary biomarkers for the early ...diagnosis of NSCLC. Using protein mass spectrometry, urinary MDH2 was found to be abundant both in patients with lung cancer and lung cancer model mice compared with controls. Urine samples obtained as retrospective and prospective cohorts including 1091 NSCLC patients and 736 healthy controls were measured using ELISA. Patients with stage I NSCLC had higher urinary MDH2 compared with healthy controls. The area under the receiver‐operating characteristic curve (AUC) for the urinary MDH2 was 0.7679 and 0.7234 in retrospective and prospective cohorts to distinguish stage I cases from controls. Urinary MDH2 levels correlated with gender and smoking history. MDH2 expression levels were elevated in lung cancer tissues. MDH2 knockdown using shRNA inhibited the proliferation of lung cancer cells. Our study demonstrated that urinary MDH2 concentration was higher in early‐stage NSCLC patients compared with that in controls and that MDH2 could serve as a potential biomarker for early detection of NSCLC.
Malate dehydrogenase 2 was significantly elevated both in urine and in cancer tissues of NSCLC patients. The level of MDH2 in urine could serve as an assistant biomarker for the early diagnosis of NSCLC.
Inspired by the highly versatile natural motors, artificial micro‐/nanomotors that can convert surrounding energies into mechanical motion and accomplish multiple tasks are devised. In the past few ...years, micro‐/nanomotors have demonstrated significant potential in biomedicine. However, the practical biomedical applications of these small‐scale devices are still at an infant stage. For successful bench‐to‐bed translation, biocompatibility of micro‐/nanomotor systems is the central issue to be considered. Herein, the recent progress in micro‐/nanomotors in biocompatibility is reviewed, with a special focus on their biomedical applications. Through close collaboration between researches in the nanoengineering, material chemistry, and biomedical fields, it is expected that a promising real‐world application platform based on micro‐/nanomotors will emerge in the near future.
The biocompatibility of artificial micro‐/nanomotors is essential for real‐world biomedical applications. Recent progress about biocompatible micro‐/nanomotor systems that are based on biocompatible framework materials, chemical fuels (e.g., water, glucose, urea, and acid), external fields (e.g., magnetic field, light, and ultrasound) and biohybrid, is discussed here.
Herein we describe a mild method for the dual C(sp3)−H bond functionalization of saturated nitrogen‐containing heterocycles through a sequential visible‐light photocatalyzed dehydrogenation/2+2 ...cycloaddition procedure. As a complementary approach to the well‐established use of iminium ion and α‐amino radical intermediates, the elusive cyclic enamine intermediates were effectively generated by photoredox catalysis under mild conditions and efficiently captured by acetylene esters to form a wide array of bicyclic amino acid derivatives, thus enabling the simultaneous functionalization of two vicinal C(sp3)−H bonds.
A great team: A dual C(sp3)−H bond functionalization strategy was developed by merging dehydrogenation under visible‐light photocatalysis with a 2+2 cycloaddition reaction in a sequential process. This method enabled cyclobutene rings to be fused to various saturated nitrogen‐containing heterocycles to produce a series of cyclic amino acid derivatives.
Information security has gained increasing attention in the past decade, leading to the development of advanced materials for anti‐counterfeiting, encryption and instantaneous information display. ...However, it remains challenging to achieve high information security with simple encryption procedures and low‐energy stimuli. Herein, a series of strain/temperature‐responsive liquid crystal elastomers (LCEs) are developed to achieve dual‐modal, multi‐level information encryption and real‐time, rewritable transient information display. The as‐prepared polydomain LCEs can change from an opaque state to a transparent state under strain or temperature stimuli, with the transition strains or temperatures highly dependent on the concentration of long‐chain flexible spacers. Information encrypted by different LCE inks can be decrypted under specific strains or temperatures, leading to multi‐level protection of information security. Furthermore, with the combination of the phase transition of polydomain LCEs and the photothermal effect of multi‐walled carbon nanotubes (MWCNTs), we achieved a repeatable transient information display by using near‐infrared (NIR) light as a pen for writing. This study provides new insight into the development of advanced encryption materials with versatility and high security for broad applications.
A series of dual‐responsive polydomain liquid crystal elastomers (LCEs) are developed, which can change from opaque to transparent states under strain or temperature stimuli. The as‐prepared LCEs can achieve multi‐level information encryption based on strain response and real‐time, rewritable transient information display upon incorporating photothermal multi‐walled carbon nanotubes.
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•Fe0.2Ni0.8-P0.5S0.5 nanoarrays are prepared by the electrodeposition method.•Bimetallic doping improves the electrode intrinsic activity.•Bimetallic doping modulates surface ...hydrophobic/hydrophilic properties.•The bifunctional electrodes are utilized for high-efficiency AEMWE.
Anion exchange membrane water electrolysis (AEMWE) is considered as a promising approach to large-scale hydrogen production. However, the performance of AEMWE is limited by the slow reaction kinetics of the catalyst and poor mass transport of gases and electrolyte at high current densities. Herein, we report Fe0.2Ni0.8-P0.5S0.5 nanoisland arrays as an efficient bifunctional catalyst with ultralow overpotentials of 85 mV (for HER) and 180 mV (for OER) to achieve a current density of 10 mA cm−2. Density functional theory calculations reveal that bimetallic doping of Fe0.2Ni0.8-P0.5S0.5 effectively improve the intrinsic activity. Particularly, the Fe0.2Ni0.8-P0.5S0.5 electrode is endowed with superhydrophilicity and aerophobicity, which not only facilitates to the exposure of active sites, but also markedly enhance gas and electrolye diffusion at high current density. Therefore, the AEMWE based on the Fe0.2Ni0.8-P0.5S0.5 bifunctional electrodes delivers a current density of 2.5 A cm−2 at 2.0 V. Moreover, the AEMWE maintained long-term operation without obvious performance degradation for 300 h.
Low‐cost and stable sodium‐layered oxides (such as P2‐ and O3‐phases) are suggested as highly promising cathode materials for Na‐ion batteries (NIBs). Biphasic hybridization, mainly involving P2/O3 ...and P2/P3 biphases, is typically used to boost their electrochemical performances. Herein, a P3/O3 intergrown layered oxide (Na2/3Ni1/3Mn1/3Ti1/3O2) as high‐rate and long‐life cathode for NIBs via tuning the amounts of Ti substitution in Na2/3Ni1/3Mn2/3−xTixO2 (x = 0, 1/6, 1/3, 2/3) is demonstrated. The X‐ray diffraction (XRD) Rietveld refinement and aberration‐corrected scanning transmission electron microscopy show the co‐existence of P3 and O3 phases, and density functional theory calculation corroborates the appearance of the anomalous O3 phase at the Ti substitution amount of 1/3. The P3/O3 biphasic cathode delivers an unexpected rate capability (≈88.7% of the initial capacity at a high rate of 5 C) and cycling stability (≈68.7% capacity retention after 2000 cycles at 1 C), superior to those of the sing phases P3‐Na2/3Ni1/3Mn2/3O2, P3‐Na2/3Ni1/3Mn1/2Ti1/6O2, and O3‐Na2/3Ni1/3Ti2/3O2. The highly reversible structural evolution of the P3/O3 integrated cathode observed by ex situ XRD, ex situ X‐ray absorption spectra, and the rapid Na+ diffusion kinetics, underpin the enhancement. These results show the important role of P3/O3 biphasic hybridization in designing and engineering layered oxide cathodes for NIBs.
P3/O3 biphasic Na2/3Ni1/3Mn1/3Ti1/3O2 cathode material is prepared for Na‐ion batteries by tuning the Ti amounts. This P3/O3 intergrown cathode delivers superior rate capability and cycling stability to those of the pristine P3 and O3 phases, which are underpinned by the observed highly reversible structural transition of P3/O3 biphase and the rapid Na+ diffusion kinetics.
When operating within the environments rich with sodium chloride, steel bars of reinforced concrete structures are often subject to corrosion caused by surrounding erosive materials, and the ...associated rust expansion force due to corrosion takes a critical role in determining the durability of relevant reinforced concrete structures. By investigating the corrosion course of steel reinforcement with theory of elasticity, a numerical rust expansion model is established for the moment of concrete surface rupture based on non-uniform sin function. Cuboid reinforced concrete specimen with squared cross sections is tested to analyze the rust expansion when concrete cracks due to corrosive forces. The utility of the established expansion model is validated by numerical simulation with Abaqus through the comparison between the associated outcomes. The impacts of steel bar diameter and concrete cover thickness on the magnitude of rust expansion force are discussed.
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