Large Band Gap Narrowing and Prolonged Carrier Lifetime of (C 4 H 9 NH 3 ) 2 PbI 4 under High Pressure
Not Available
2D organic-inorganic halide perovskites↗
Engineering topics
Wang, Lin
Publications and source records attributed to Wang, Lin.
Anion-adaptive crystalline cationic material for 99 TcO 4 - trapping
Efficient anion recognition is of great significance for radioactive 99 TcO 4 - decontamination, but it remains a challenge for traditional sorbents. Herein, we put forward a tactic using soft crystalline cationic material with anion-adaptive dynamics for 99 TcO 4 - sequestration. A cucurbit[8]uril-based supramolecular metal-organic material is produced through a multi-component assembly strategy and used as a sorbent for effective trapping of TcO 4 - . Excellent separation of TcO 4 - /ReO 4 - is demonstrated by fast removal kinetics, good sorption capacity and high distribution coefficient. Remarkably, the most superior selectivity among metal-organic materials reported so far, together with good hydrolytic stability, indicates potential for efficient TcO 4 - removal. The structure incorporating ReO 4 - reveals that the supramolecular framework undergoes adaptive reconstruction facilitating the effective accommodation of TcO 4 - /ReO 4 - . The results highlight opportunities for development of soft anion-adaptive sorbents for highly selective anion decontamination.
36 MATERIALS SCIENCE↗
Pressure-induced fluorescence enhancement of FA α PbBr 2+α composite perovskites
FAPbBr 3 crystals were stabilized by the endotaxy passivation by FA 4 PbBr 6 during high pressure compression.
Nguyen, Lan Anh Thi↗
Band Structure Engineering of Interfacial Semiconductors Based on Atomically Thin Lead Iodide Crystals
To explore new constituents in two-dimensional (2D) materials and to combine their best in van der Waals heterostructures is in great demand as being a unique platform to discover new physical phenomena and to design novel functionalities in interface-based devices. Here in this paper, PbI 2 crystals as thin as a few layers are synthesized, particularly through a facile low-temperature solution approach with crystals of large size, regular shape, different thicknesses, and high yields. As a prototypical demonstration of band engineering of PbI 2 -based interfacial semiconductors, PbI 2 crystals are assembled with several transition metal dichalcogenide monolayers. The photoluminescence of MoS 2 is enhanced in MoS 2 /PbI 2 stacks, while a dramatic photoluminescence quenching of WS 2 and WSe 2 is revealed in WS2/PbI 2 and WSe 2 /PbI2 stacks. This is attributed to the effective heterojunction formation between PbI 2 and these monolayers; type I band alignment in MoS 2 /PbI2 stacks, where fast-transferred charge carriers accumulate in MoS 2 with high emission efficiency, results in photoluminescence enhancement, and type II in WS 2 /PbI 2 and WSe 2 /PbI 2 stacks, with separated electrons and holes suitable for light harvesting, results in photoluminescence quenching. The results demonstrate that MoS 2 , WS 2 , and WSe 2 monolayers with similar electronic structures show completely distinct light–matter interactions when interfacing with PbI 2 , providing unprecedented capabilities to engineer the device performance of 2D heterostructures.
36 MATERIALS SCIENCE↗
Effective Removal of Anionic Re(VII) by Surface-Modified Ti 2 CT x MXene Nanocomposites: Implications for Tc(VII) Sequestration
Environmental contamination by 99 Tc(VII) from radioactive wastewater streams is of particular concern due to the long half-life of 99 Tc and high mobility of pertechnetate. Here in this paper, we report a novel MXene-polyelectrolyte nanocomposite with three-dimensional networks for enhanced removal of perrhenate, which is pertechnetate simulant. The introduction of poly(diallyldimethylammonium chloride) (PDDA) regulates the surface charge and improves the stability of Ti 2 CT x nanosheet, resulting in Re(VII) removal capacity of up to 363 mg g –1 , and fast sorption kinetics. The Ti 2 CT x /PDDA nanocomposite furthermore exhibits good selectivity for ReO 4 – when competing anions (such as Cl – and SO 4 2– ) coexist at a concentration of 1800 times. The immobilization mechanism was confirmed as a sorption-reduction process by batch sorption experiments and X-ray photoelectron spectroscopy. The pH-dependent reducing activity of Ti 2 CT x /PDDA nanocomposite toward Re(VII) was clarified by X-ray absorption spectroscopy. As the pH increases, the local environment gradually changes from octahedral-coordinated Re(IV) to tetrahedral-coordinated Re(VII). The overall results suggest that Ti 2 CT x /PDDA nanocomposite may be a promising candidate for efficient elimination of Tc contamination. The reported surface modification strategy might result in applications of MXene-based materials in environmental remediation of other oxidized anion pollutants.
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
Pareto Optimality Explanation of the Glycolytic Alternatives in Nature
The Entner-Doudoroff (ED) and Embden-Meyerhof-Parnas (EMP) glycolytic pathways are largely conserved across glycolytic species in nature. Is this a coincidence, convergent evolution or there exists a driving force towards either of the two pathway designs? We addressed this question by first employing a variant of the optStoic algorithm to exhaustively identify over 11,916 possible routes between glucose and pyruvate at different pre-determined stoichiometric yields of ATP. Subsequently, we analyzed the thermodynamic feasibility of all the pathways at physiological metabolite concentrations and quantified the protein cost of the feasible solutions. Pareto optimality analysis between energy efficiency and protein cost reveals that the naturally evolved ED and EMP pathways are indeed among the most protein cost-efficient pathways in their respective ATP yield categories and remain thermodynamically feasible across a wide range of ATP/ADP ratios and pathway intermediate metabolite concentration ranges. In contrast, pathways with higher ATP yield (>2) while feasible, are bound within stringent and often extreme operability ranges of cofactor and intermediate metabolite concentrations. The preponderance of EMP and ED is thus consistent with not only optimally balancing energy yield vs. enzyme cost but also with ensuring operability for wide metabolite concentration ranges and ATP/ADP ratios.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Creation and analysis of biochemical constraint-based models using the COBRA Toolbox v.3.0
Not provided.
Biochemistry & Molecular Biology↗
Peak Annotation and Verification Engine for Untargeted LC–MS Metabolomics
Untargeted metabolomics can detect more than 10 000 peaks in a single LC–MS run. The correspondence between these peaks and metabolites, however, remains unclear. Here in this study, we introduce a Peak Annotation and Verification Engine (PAVE) for annotating untargeted microbial metabolomics data. The workflow involves growing cells in 13 C and 15 N isotope-labeled media to identify peaks from biological compounds and their carbon and nitrogen atom counts. Improved deisotoping and deadducting are enabled by algorithms that integrate positive mode, negative mode, and labeling data. To distinguish metabolites and their fragments, PAVE experimentally measures the response of each peak to weak in-source collision induced dissociation, which increases the peak intensity for fragments while decreasing it for their parent ions. The molecular formulas of the putative metabolites are then assigned based on database searching using both m/z and C/N atom counts. Application of this procedure to Saccharomyces cerevisiae and Escherichia coli revealed that more than 80% of peaks do not label, i.e., are environmental contaminants. More than 70% of the biological peaks are isotopic variants, adducts, fragments, or mass spectrometry artifacts yielding ~2000 apparent metabolites across the two organisms. About 650 match to a known metabolite formula based on m/z and C/N atom counts, with 220 assigned structures based on MS/MS and/or retention time to match to authenticated standards. Lastly, PAVE enables systematic annotation of LC–MS metabolomics data with only ~4% of peaks annotated as apparent metabolites.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Interleukin-18 binding protein attenuates lipopolysaccharide-induced acute lung injury in mice via suppression NF-κB and activation Nrf2 pathway
Highlights: • IL-18BP protectes against LPS-induced ALI. • IL-18BP inhibits the activation of NF-κB in LPS-induced ALI mice. • IL-18BP enhances the activation of Nrf2 in LPS-induced ALI mice. Interleukin (IL)-18 belongs to a rather large IL-1 gene family and is a proinflammatory cytokine. IL-18 plays important roles in lung injury. IL-18 binding protein (IL-18BP), a natural antagonist of IL-18, binds IL-18 with high affinity. IL-18BP is able to neutralize IL-18 biological activity and has a protective effect against renal fibrosis. The aim of this study was to evaluate the potential protective effect of IL-18BP on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice and to illuminate the underlying mechanisms. Results indicated that pretreatment with IL-18BP significantly attenuated LPS-induced pulmonary pathological injury. Meanwhile, IL-18BP pretreatment markedly inhibited infiltration of inflammatory cell and release of inflammatory factor in ALI mice in vivo and in primary macrophages after LPS insult in vitro. IL-18BP treatment dramatically reduced oxidative stress through increasing superoxide dismutase (SOD) and glutathione (GSH) contents, and decreasing the levels of malondialdehyde (MDA) and reactive oxygen species (ROS) in LPS-induced ALI mice and primary macrophages. Additionally, IL-18BP was also observed to markedly decreased the activation of nuclear factor-kappa B (NF-κB) and upregulated the nuclear factor erythroid 2-related factor 2 (Nrf2). Taken together, IL-18BP possessed protective effect against LPS-induced ALI, which might be associated with its regulation of NF-κB and Nrf2 activities. The results rendered IL-18BP worthy of further development into a pharmaceutical drug for the treatment of ALI.
60 APPLIED LIFE SCIENCES↗
Anisotropic ultraviolet-plasmon dispersion in black phosphorus
Via momentum-resolved electron energy loss spectroscopy (EELS) coupled with scanning transmission electron microscopy, we have studied the dispersion relation of interband plasmonic modes in the ultraviolet in black phosphorus. We find that the dispersion of the interband plasmons is anisotropic. Experimental results are reproduced by density functional theory, by taking into account both the anisotropy of the single-particle response function, arising from the anisotropic band structure, and the damping. Moreover, our theoretical model also indicates the presence of low-energy excitations in the near-infrared that are selectively active in the armchair direction, whose existence has been experimentally validated by high-resolution EELS (HREELS) in reflection mode.
77 NANOSCIENCE AND NANOTECHNOLOGY↗
Li-ion battery material under high pressure: amorphization and enhanced conductivity of Li 4 Ti 5 O 12
Lithium titanium oxide (Li 4 Ti 5 O 12 , LTO), a 'zero-strain' anode material for lithium-ion batteries, exhibits excellent cycling performance. However, its poor conductivity highly limits its applications. Here, the structural stability and conductivity of LTO were studied using in situ high-pressure measurements and first-principles calculations. LTO underwent a pressure-induced amorphization (PIA) at 26.9 GPa. The impedance spectroscopy revealed that the conductivity of LTO improved significantly after amorphization and that the conductivity of decompressed amorphous LTO increased by an order of magnitude compared with its starting phase. Furthermore, our calculations demonstrated that the different compressibility of the LiO 6 and TiO 6 octahedra in the structure was crucial for the PIA. The amorphous phase promotes Li + diffusion and enhances its ionic conductivity by providing defects for ion migration. Our results not only provide an insight into the pressure depended structural properties of a spinel-like material, but also facilitate exploration of the interplay between PIA and conductivity.
25 ENERGY STORAGE↗
Two different restriction-modification systems for degrading exogenous DNA in Paenibacillus polymyxa
Highlights: • Dam methylated DNA from E. coli is strongly restricted in P. polymyxa. • DNA without Dam methylation is moderately restricted in P. polymyxa. • P. polymyxa is equipped with DNA-methylation-dependent and -independent R-M systems. • Genetic manipulation tools in P. polymyxa. Accompanied by benefits from horizontally transferred genes, bacteria have to face the risk of the invasion of dangerous genes. Bacteria often use the restriction-modification (R-M) system, which is consisted of methyl transferase (MEase) and restrictase (REase), to protect self-DNA and defend against foreign DNA. Paenibacillus polymyxa, widely used as growth promoting rhizobacteria in agriculture, can also produce compounds of medical and industrial interests. It is unclear whether R-M systems exist in P. polymyxa. In this study, we used a shuttle plasmid with epigenetic modification from different bacteria to explore R-M systems in P. polymyxa. We found that DNA which is methylated by DNA adenine methyltransferase (Dam) in E. coli was strongly restricted, indicating the presence of a Dam-methylation-dependent R-M system in P. polymyxa. Whereas, DNA from a dam{sup -} E. coli strain was also moderately restricted, indicating the presence of a Dam-methylation-independent R-M system. Degradation of plasmid DNA with Dam methylation by cell-free protein extract of P. polymyxa provides additional evidence for the presence of Dam-methylation-dependent R-M system. Taken together, our work showed that there are two different types of R-M system in P. polymyxa, providing a foundation for the study of innate immunity in P. polymyxa and for the development of genetic engineering tools in P. polymyxa.
60 APPLIED LIFE SCIENCES↗
Efficient U(VI) Reduction and Sequestration by Ti 2 CT x MXene
Although reduction of highly mobile U(VI) to less soluble U(IV) has been long considered an effective approach to in situ environmental remediation of uranium, candidate reducing agents are largely limited to Fe-based materials and microbials. The importance of titanium-containing compounds in natural uranium ore deposits suggests a role for titanium in uranium migration. In this report, for the first time, a two-dimensional transition metal carbide, Ti 2 CT x , is shown to efficiently remove uranium via a sorption-reduction strategy. Batch experiments demonstrate that Ti 2 CT x exhibits excellent U(VI) removal over a wide pH range, with an uptake capacity of 470 mg g –1 at pH 3.0. The mechanism for U(VI) to U(IV) reduction by Ti 2 CT x was deciphered by X-ray absorption spectroscopy and diffraction and photoelectron spectroscopy. The reduced U(IV) species at low pH is identified as mononuclear with bidendate binding to the MXene substrate. At near-neutral pH, nanoparticles of the UO 2+x phase adsorb to the substrate with some Ti 2 CT x transformed to amorphous TiO 2 . A subsequent in-depth study suggests Ti 2 CT x materials may be potential candidates for permeable reactive barriers in the treatment of wastewaters from uranium mining. Finally, this work highlights reduction-induced immobilization of U(VI) by Ti 2 CT x MXene including a pH-dependent reduction mechanism that might promote applications of titanium-based materials in the elimination of other oxidized contaminants.
36 MATERIALS SCIENCE↗
Additive-Free Ruthenium-Catalyzed Hydrogen Production from Aqueous Formaldehyde with High Efficiency and Selectivity
In this study, an efficient water-soluble ruthenium complex was developed for selective hydrogen production from aqueous formaldehyde under mild conditions with a high yield (~95%). Hydrogen production by this catalytic system proceeds without using any additives or organic solvents, leading to a high turnover frequency (8300 h –1 ) and a record turnover number of 24 000. Additionally, based on mechanistic experiments and density functional theory (DFT) calculations, a step-by-step mechanism has been proposed for the catalytic cycle.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
xxing9703/PAVE
Untargeted metabolomics can detect more than 10 000 peaks in a single LC–MS run. The correspondence between these peaks and metabolites, however, remains unclear. Here, we introduce a Peak Annotation and Verification Engine (PAVE) for annotating untargeted microbial metabolomics data. The workflow involves growing cells in 13C and 15N isotope-labeled media to identify peaks from biological compounds and their carbon and nitrogen atom counts. Improved deisotoping and deadducting are enabled by algorithms that integrate positive mode, negative mode, and labeling data. To distinguish metabolites and their fragments, PAVE experimentally measures the response of each peak to weak in-source collision induced dissociation, which increases the peak intensity for fragments while decreasing it for their parent ions. The molecular formulas of the putative metabolites are then assigned based on database searching using both m/z and C/N atom counts. Application of this procedure to Saccharomyces cerevisiae and Escherichia coli revealed that more than 80% of peaks do not label, i.e., are environmental contaminants. More than 70% of the biological peaks are isotopic variants, adducts, fragments, or mass spectrometry artifacts yielding ∼2000 apparent metabolites across the two organisms. About 650 match to a known metabolite formula based on m/z and C/N atom counts, with 220 assigned structures based on MS/MS and/or retention time to match to authenticated standards. Thus, PAVE enables systematic annotation of LC–MS metabolomics data with only ∼4% of peaks annotated as apparent metabolites.
Xing, Xi↗
Pressure-induced isostructural phase transition and charge transfer in superconducting FeSe
Here, we present extensive investigations of the crystallographic phase diagram and electronic properties of the Fe-based superconductor FeSe under extreme conditions (high pressure (HP) and low temperature (LT)) by synchrotron X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). An isostructural phase transition (Tetragonal (T) →high-pressure Tetragonal (T')) is discovered in FeSe at ~2.8 GPa based on the axial ratio c/a with finer pressure step as observed in Fe-As-based superconductor such as EuFe 2 As 2 . We also find a pressure-induced T' → MnP-type phase transition at 7.6 GPa in FeSe, which is consistent with the documented pressure-induced high-spin → low-spin transition (~6–7 GPa). These results reveal the pressure-induced structural phase transition sequence in FeSe at room temperature to be T → T' → T'+MnP-type at pressures of 0–10.6 GPa, enriching the crystallographic phase diagram. The HPLT XRD data also indicate that a sluggish structural phase transition ( Cmma → Pnma ) begins at 7.5 GPa, and these two phases coexist up to 26.5 GPa. The HP X-ray absorption near-edge spectroscopy (XANES) measurement shows that E o of Se experiences a pressure-induced shift to high energy, evidencing strongly charge transfer between Fe and Se under high pressure. Our results shed lights on the correlation between crystallographic/electronic structure and superconductivity in this material.
36 MATERIALS SCIENCE↗
The three branches of the unfolded protein response exhibit differential significance in breast cancer growth and stemness
Highlights: • UPR sensors are highly expressed in cancers and correlate with SOX2 and OCT4. • Inhibition/silencing of PERK and ATF6α strongly affect breast cancer growth and CSC. • An appropriate UPR level is required for the mammosphere formation and maintenance. • UPR and pluripotency pathways interact and influence each other. • C/EBPδ interacts with SOX2 and UPR transcription factors, modulating both pathways. The unfolded protein response (UPR) is widely activated in cancers. The mammalian UPR encompasses three signaling branches, namely inositol-requiring enzyme-1α (IRE1α), protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK) and activating transcription factor 6α (ATF6α). The functional significance of each branch in tumorigenesis is incompletely understood, especially in cancer stem cells (CSCs). Here, we report that inhibition and silencing of the three UPR sensors has differential effects on breast cancer growth and the CSC population. The levels of PERK and ATF6α strongly correlate with the expression of sex determining region Y (SRY)-box 2 (SOX2), a pluripotency regulator, in human breast cancer tissues. UPR activation is also elevated in the CSC-enriched mammospheres. Inhibition of the UPR sensors or excess ER stress markedly reduces the formation and maintenance of mammospheres, suggesting that an appropriate level of UPR activation is critical for the CSC survival. Mechanistically, transcription factors from UPR and pluripotency pathways interact and reciprocally influence each other. A transcription modulator, CCAAT-enhancer-binding protein delta (C/EBPδ), interacts with pluripotency regulator, SOX2, and UPR transcription factors, thus likely serving as a link to coordinate UPR and pluripotency maintenance in CSCs. Our findings demonstrate that UPR is critical for both cancer growth and pluripotency, and highlight the differential role and complexity of the three UPR branches in tumorigenesis.
60 APPLIED LIFE SCIENCES↗