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Abstract The increasing need to control anthropogenic CO2 emissions and conversion to fuels features the necessity for innovative solutions, one of which is photoelectrochemical system. This approach, capable of yielding gaseous production progressively, is facing challenges for liquid fuels generation due to optical, electrical, and catalytic properties. This study employs a standalone photoelectrochemical setup, in which InGaP/GaAs/Ge photoanode is integrated with tin-modified bismuth oxide cathode to convert CO2 into liquid formic acid. In unassisted two-electrode assembly, setup exemplifies its operational durability for 100 h, during which it maintains an average Faradaic efficiency of 88% with 17.3 mmol L–1 h–1 of yield, thereby excelling in average solar-to-fuel conversion efficiency at 12% with 60% of electrical energy efficiency under one sun illumination. This significant performance is further associated with metal-semiconductor interface formation between tin and bismuth oxide, which bridges electronic structures and generates an electric field at their interfaces. This study outperforms conventional solar-driven systems in operational durability and liquid fuel production.

Abstract In two-dimensional CFTs with a large central charge, the level-two BPZ equation governs the heavy-light scalar four-point correlator when the light probe scalar has dimension h = − 1 2 $$ -\frac{1}{2} $$ ; the corresponding linear ordinary differential equation can be recast into a schematic form x 2 u xx + u = 0. In this paper, we make an observation that in a class of four-dimensional CFTs with a large central charge, the heavy-light scalar correlator in the near-lightcone limit obeys a similar equation, x 3 u xxxy + u = 0, when the light scalar has dimension ∆ = –1. We focus on the multi-stress tensor sector of the theory and also discuss the corresponding equations for the cases with ∆ = –2, –3. The solutions to these linear partial differential equations in higher dimensions are shown, after a suitable change of variables, to reproduce the near-lightcone correlators previously obtained via holography and the conformal bootstrap.

Abstract We consider thermal stress-tensor two-point functions in holographic theories in the near-lightcone regime and analyse them using the operator product expansion (OPE). In the limit we consider only the leading-twist multi-stress tensors contribute and the correlators depend on a particular combination of lightcone momenta. We argue that such correlators are described by three universal functions, which can be holographically computed in Einstein gravity; higher-derivative terms in the gravitational Lagrangian enter the arguments of these functions via the cubic stress-tensor couplings and the thermal stress-tensor expectation value in the dual CFT. We compute the retarded correlators and observe that in addition to the perturbative OPE, which contributes to the real part, there is a non-perturbative contribution to the imaginary part.

Abstract Lithium (Li) is an essential element in modern energy production and storage devices. Technology to extract Li from seawater, which contains ~ 230 billion tons of Li, offers a solution to the widespread concern regarding quantitative and geographical limitations of future Li supplies. To obtain green Li from seawater, we propose an unassisted photoelectrochemical (PEC) Li extraction system based on an III-V-based triple-junction (3J) photoelectrode and a Li-ion selective membrane with only sunlight as an input. A light-harvesting/catalysis decoupling scheme yielded a 3J photoelectrode with excellent light-harvesting and catalysis reaction capabilities and superb stability over the 840 h of the extraction process. It allows the system to successfully enrich seawater Li by 4,350 times (i.e., from 0.18 ppm to 783.56 ppm) after three extraction stages. The overall reaction of the unassisted PEC green Li extraction system achieved 2.08 mg kJ−1 of solar-to-Li efficiency and 3.65% of solar-to-hydrogen efficiency. Graphical Abstract Photoelectrochemical (PEC) lithium extraction device is designed to explore lithium from seawater for the first time. The PEC cell with a triple-junction (InGaP/GaAs/Ge) photoelectrode and light-harvesting/catalysis decoupling scheme is constructed, offering a suitable operating potential and superb stability to the membrane-based extraction process in the seawater. The device can successfully enrich lithium by 4,350 times (from 0.18 to 783.56 ppm).

Abstract Averaged Null Energy Conditions (ANECs) hold in unitary quantum field theories. In conformal field theories, ANECs in states created by the application of the stress tensor to the vacuum lead to three constraints on the stress-tensor three-point couplings, depending on the choice of polarization. The same constraints follow from considering two-point functions of the stress tensor in a thermal state and focusing on the contribution of the stress tensor in the operator product expansion (OPE). One can observe this in holographic Gauss-Bonnet gravity, where ANEC saturation coincides with the appearance of superluminal signal propagation in thermal states. We show that, when this happens, the corresponding generalizations of ANECs for higher-spin multi-stress tensor operators with minimal twist are saturated as well and all contributions from such operators to the thermal two-point functions vanish in the lightcone limit. This leads to a special near-lightcone behavior of the thermal stress-tensor correlators — they take the vacuum form, independent of temperature.

Abstract Background Tumor cells may aberrantly express metabolic enzymes to adapt to their environment for survival and growth. Targeting cancer‐specific metabolic enzymes is a potential therapeutic strategy. Phosphoenolpyruvate carboxykinase (PEPCK) catalyzes the conversion of oxaloacetate to phosphoenolpyruvate and links the tricarboxylic acid cycle and glycolysis/gluconeogenesis. Mitochondrial PEPCK (PEPCK‐M), encoded by PCK2, is an isozyme of PEPCK and is distributed in mitochondria. Overexpression of PCK2 has been identified in many human cancers and demonstrated to be important for the survival program initiated upon metabolic stress in cancer cells. We evaluated the expression status of PEPCK‐M and investigated the function of PEPCK‐M in breast cancer. Methods We checked the expression status of PEPCK‐M in breast cancer samples by immunohistochemical staining. We knocked down or overexpressed PCK2 in breast cancer cell lines to investigate the function of PEPCK‐M in breast cancer. Results PEPCK‐M was highly expressed in estrogen receptor‐positive (ER+) breast cancers. Decreased cell proliferation and G0/G1 arrest were induced in ER+ breast cancer cell lines by knockdown of PCK2. PEPCK‐M promoted the activation of mTORC1 downstream signaling molecules and the E2F1 pathways in ER+ breast cancer. In addition, glucose uptake, intracellular glutamine levels, and mTORC1 pathways activation by glucose and glutamine in ER+ breast cancer were attenuated by PCK2 knockdown. Conclusion PEPCK‐M promotes proliferation and cell cycle progression in ER+ breast cancer via upregulation of the mTORC1 and E2F1 pathways. PCK2 also regulates nutrient status‐dependent mTORC1 pathway activation in ER+ breast cancer. Further studies are warranted to understand whether PEPCK‐M is a potential therapeutic target for ER+ breast cancer.

Abstract Background Phosphatase and tensin homolog (PTEN) is a tumor suppressor. Low PTEN expression has been observed in pancreatic neuroendocrine tumors (pNETs) and is associated with increased liver metastasis and poor survival. Vascular endothelial growth factor receptor 3 (VEGFR3) is a receptor tyrosine kinase and is usually activated by binding with vascular endothelial growth factor C (VEGFC). VEGFR3 has been demonstrated with lymphangiogenesis and cancer invasiveness. PTEN is also a phosphatase to dephosphorylate both lipid and protein substrates and VEGFR3 is hypothesized to be a substrate of PTEN. Dual-specificity phosphatase 19 (DUSP19) is an atypical DUSP and can interact with VEGFR3. In this study, we investigated the function of PTEN on regulation of pNET invasiveness and its association with VEGFR3 and DUSP19. Methods PTEN was knocked down or overexpressed in pNET cells to evaluate its effect on invasiveness and its association with VEGFR3 phosphorylation. In vitro phosphatase assay was performed to identify the regulatory molecule on the regulation of VEGFR3 phosphorylation. In addition, immunoprecipitation, and immunofluorescence staining were performed to evaluate the molecule with direct interaction on VEGFR3 phosphorylation. The animal study was performed to validate the results of the in vitro study. Results The invasion and migration capabilities of pNETs were enhanced by PTEN knockdown accompanied with increased VEGFR3 phosphorylation, ERK phosphorylation, and increased expression of epithelial–mesenchymal transition molecules in the cells. The enhanced invasion and migration abilities of pNET cells with PTEN knockdown were suppressed by addition of the VEGFR3 inhibitor MAZ51, but not by the VEGFR3-Fc chimeric protein to neutralize VEGFC. VEGFR3 phosphorylation is responsible for pNET cell invasiveness and is VEGFC-independent. However, an in vitro phosphatase assay failed to show VEGFR3 as a substrate of PTEN. In contrast, DUSP19 was transcriptionally upregulated by PTEN and was shown to dephosphorylate VEGFR3 via direct interaction with VEGFR3 by an in vitro phosphatase assay, immunoprecipitation, and immunofluorescence staining. Increased tumor invasion into peripheral tissues was validated in xenograft mouse model. Tumor invasion was suppressed by treatment with VEGFR3 or MEK inhibitors. Conclusions PTEN regulates pNET invasiveness via DUSP19-mediated VEGFR3 dephosphorylation. VEGFR3 and DUSP19 are potential therapeutic targets for pNET treatment.

Abstract By applying the stress-tensor-scalar operator product expansion (OPE) twice, we search for algebraic structures in d = 4 conformal field theories (CFTs) with a pure Einstein gravity dual. We find that a rescaled mode operator defined by an integral of the stress tensor T ++ on a d = 2 plane satisfies a Virasoro-like algebra when the dimension of the scalar is large. The structure is enhanced to include a Kac-Moody-type algebra if we incorporate the T −− component. In our scheme, the central terms are finite. It remains challenging to directly compute the stress-tensor sector of d = 4 scalar four-point functions at large central charge, which, based on holography and bootstrap methods, were recently shown to have a Virasoro/ W $$ \mathcal{W} $$ -algebra vacuum block-like structure.

Abstract Developing a green and energy‐saving alternative to the traditional Haber‐Bosch process for converting nitrogen into ammonia is urgently needed. Imitating from biological nitrogen fixation and photosynthesis processes, this work develops a monolithic artificial leaf based on triple junction (3J) InGaP/GaAs/Ge cell for solar‐driven ammonia conversion under ambient conditions. A gold layer serves as the catalytic site for nitrogen fixation with photogenerated electrons. The Au/Ti/3J InGaP/GaAs/Ge photoelectrochemical (PEC) device achieves high ammonia production rates and Faradaic efficiencies in a two‐electrode system without applying external potential. For example, at 0.2 sunlight intensity, the solar‐to‐ammonia (STA) conversion efficiency reaches 1.11% and the corresponding Faradaic efficiency is up to 28.9%. By integrating a Ni foil on the anode side for the oxygen evolution reaction (OER), the monolithic artificial leaf exhibits an ammonia production rate of 8.5 µg cm−2 h at 1.5 sunlight intensity. Additionally, a 3 × 3 cm unassisted wireless PEC device is fabricated that produces 1.0039 mg of ammonia in the 36‐h durability test. Thus, the new artificial leaf can successfully and directly convert solar energy into chemical energy and generate useful products in an environmentally friendly approach.

Metal confinement catalyst MoS2/Pt@TD-6%Ti (TD, TS-1/Dendritic mesoporous silica nanoparticles composite) in dendritic hierarchical pore structures was synthesized and showed excellent sulfur-resistance performance and stabilities in catalytic hydrodesulfurization reactions of probe sulfide molecules. The MoS2/Pt@TD-6%Ti catalyst combines the concepts of Pt-confinement effect and hydrogen spillover of Pt noble metal. The modified micropores of Mo/Pt@TD-6%Ti only allow the migration and dissociation of small H2 molecules (0.289 nm), and effectively keep the sulfur-containing compounds (e.g. H2S, 0.362 nm) outside. Thus, the MoS2/Pt@TD-6%Ti catalyst exhibits higher DBT and 4,6-DMDBT HDS activities because of the synergistic effect of the strong H2 dissociation ability of Pt and desulfurization ability of MoS2 with a lower catalyst cost. This new concept combining H2 dissociation performance of noble metal catalyst with the desulfurization ability of transition metal sulfide MoS2 can protect the noble metal catalyst avoiding deactivation and poison, and finally guarantee the higher activities for DBT and 4,6-DMDBT HDS.

Early diagnosis of cardiovascular diseases (CVDs) has the potential to save millions of lives each year. Sensitive quantitative measurement of blood cardiac troponin I (cTnI) is required for early diagnosis of CVDs. Porous graphitic carbon nitride (PCN) nanomaterials integrated biosensor that detects picogram/mL concentrations of cTnI is reported. PCN is an updated version of graphitic carbon nitride (GCN) with improved porosity and electronic structure. A rapid two-step chemical method was described to synthesize PCN and gold nanoparticles functionalized PCN (PCN-AuNPs). The modification of the electrode surface with PCN materials had a significant impact on the electrochemically active surface area (EASA), interfacial electron transport, aptamer immobilization, and biosensing performance. The use of PCN nanomaterial in cTnI aptasensing resulted in a 3.2-fold increase in signal amplification. PCN-AuNPs found practically applicable in human blood serum (cTnI-spiked). Furthermore, a low-cost and user-friendly sensing platform has been demonstrated by integrating a PCN-AuNPs aptasensor, a custom-made miniaturized potentiostat, and a smartphone, which provided rapid, sensitive point-of-care (PoC) analysis of cTnI. Highly sensitive detection limit (0.01 pg/mL), rapid analysis time (2 min), and small sample volume (20 μL) are the other advantages of this nano-biosensor.

X-ray detection has widespread applications in medical diagnosis, non-destructive industrial radiography and safety inspection, and especially, medical diagnosis realized by medical X-ray detectors is presenting an increasing demand. Perovskite materials are excellent candidates for high-energy radiation detection based on their promising material properties such as excellent carrier transport capability and high effective atomic number. In this review paper, we introduce X-ray detectors using all kinds of halide perovskite materials along with various crystal structures and discuss their device performance in detail. Single-crystal perovskite was first fabricated as an active material for X-ray detectors, having excellent performance under X-ray illumination due to its superior photoelectric properties of X-ray attenuation with μm thickness. The X-ray detector based on inorganic perovskite shows good environmental stability and high X-ray sensitivity. Owing to anisotropic carrier transport capability, two-dimensional layered perovskites with a preferred orientation parallel to the substrate can effectively suppress the dark current of the device despite poor light response to X-rays, resulting in lower sensitivity for the device. Double perovskite applied for X-ray detectors shows better attenuation of X-rays due to the introduction of high-atomic-numbered elements. Additionally, its stable crystal structure can effectively lower the dark current of X-ray detectors. Environmentally friendly lead-free perovskite exhibits potential application in X-ray detectors by virtue of its high attenuation of X-rays. In the last section, we specifically introduce the up-scaling process technology for fabricating large-area and thick perovskite films for X-ray detectors, which is critical for the commercialization and mass production of perovskite-based X-ray detectors.

Background: The response rate to sorafenib is limited for unresectable hepatocellular carcinoma (HCC). Little is known about the long-term outcomes of objective responders. The role of second-line therapies on the survival of sorafenib-responders is unclear. We aimed to delineate the long-term outcomes and the role of subsequent treatment after responding to sorafenib. Methods: From September 2012 to December 2019, 922 patients who received sorafenib treatment for unresectable HCC were retrospectively reviewed. Of these, 21 (2.3%) achieved a complete response (CR) and 54 (5.9%) had a partial response (PR) based on mRECIST criteria. Factors associated with survivals were analyzed. Results: During the median follow-up of 35.3 months, the median duration of response was 18.3 months (range: 2.3–45.5) for patients achieving CR and 10.0 months (range: 1.9–60.3) for PR. The median overall survival (OS) was 39.5 months [95% confidence interval (CI): 28.4–50.5] including values not yet estimable for CR and 25.8 months for PR. Patients who experienced treatment-related adverse events (TRAEs) had better median OS than those without (44.9 versus 18.1 months, p = 0.003). Eventually, 53 patients developed tumor progression; 30 patients received second-line systemic treatment including nivolumab ( n = 8), regorafenib ( n = 15), and chemotherapy ( n = 7). Sorafenib–nivolumab sequential therapy provided the best median OS versus sorafenib–regorafenib and sorafenib–chemotherapy in these patients (55.8, 39.5, and 25.5 months), respectively. Conclusions: The response is durable for advanced HCC patients with CR or PR to sorafenib. Subsequent immunotherapy seems to provide the best survival. This information is important for characterizing outcomes of sorafenib-responders and the choice of sequential treatment.

We present the mechanistic understanding of an electrochemically-driven nickel-catalyzed coupling reaction. Computational analysis reveals that the spin density is mostly residing on the nickel (Ni) center when NiII is reduced to NiI. Ni-mediated halogen atom abstraction through outer-sphere electron-transfer pathway to yield coupling products under mild conditions is demonstrated. Importantly, we have elucidated the role of NiI and Ni0 for successive coupling of benzyl bromide and benzyl chloride derivatives, respectively, to corresponding bibenzyl products. The Ni-catalyst bearing a PN3P-ligand is an effective catalyst, producing a strong ligand effect on the reactivity and selectivity for the homocoupling reactions.

Abstract Following recent work on heavy-light correlators in higher-dimensional conformal field theories (CFTs) with a large central charge C T , we clarify the properties of stress tensor composite primary operators of minimal twist, [T m ], using arguments in both CFT and gravity. We provide an efficient proof that the three-point coupling O L O L T m $$ \left\langle {\mathcal{O}}_L{\mathcal{O}}_L\left[{T}^m\right]\right\rangle $$ , where O L $$ {\mathcal{O}}_L $$ is any light primary operator, is independent of the purely gravitational action. Next, we consider corrections to this coupling due to additional interactions in AdS effective field theory and the corresponding dual CFT. When the CFT contains a non-zero three-point coupling TT O L $$ \left\langle TT{\mathcal{O}}_L\right\rangle $$ , the three-point coupling O L O L T 2 $$ \left\langle {\mathcal{O}}_L{\mathcal{O}}_L\left[{T}^2\right]\right\rangle $$ is modified at large C T if TT O L ∼ C T $$ \left\langle TT{\mathcal{O}}_L\right\rangle \sim \sqrt{C_T} $$ . This scaling is obeyed by the dilaton, by Kaluza-Klein modes of prototypical supergravity compactifications, and by scalars in stress tensor multiplets of supersymmetric CFTs. Quartic derivative interactions involving the graviton and the light probe field dual to O L $$ {\mathcal{O}}_L $$ can also modify the minimal-twist couplings; these local interactions may be generated by integrating out a spin-ℓ ≥ 2 bulk field at tree level, or any spin ℓ at loop level. These results show how the minimal-twist OPE coefficients can depend on the higher-spin gap scale, even perturbatively.

Abstract We consider two d ≥ 2 conformal field theories (CFTs) glued together along a codimension one conformal interface. The conformal anomaly of such a system contains both bulk and interface contributions. In a curved-space setup, we compute the heat kernel coefficients and interface central charges in free theories. The results are consistent with the known boundary CFT data via the folding trick. In d = 4, two interface invariants generally allowed as anomalies turn out to have vanishing interface charges. These missing invariants are constructed from components with odd parity with respect to flipping the orientation of the defect. We conjecture that all invariants constructed from components with odd parity may have vanishing coefficient for symmetric interfaces, even in the case of interacting interface CFT.

FeCuCo over aluminum oxide catalyst was prepared to catalytically degrade polystyrene (PS) into ethylbenzene (EB) under mild conditions. This catalyst was characterized by XRD, SEM, STEM-EELS, STEM-EDS, XPS, and physical properties. A significant selectivity toward EB formation at 250 °C was achieved in the absence of hydrogen with 82% liquid yield. End-chain session and cross-linking reactions are proposed to be the dominant pathways in the degradation of PS over FeCuCo to form EB. Keywords: Polystyrene, Catalytic-degradation, Ethylbenzene, Selective-conversion

V-substituted polymolybdenum phosphoric acid (PVxMo) supported on mesoporous silica was prepared and investigated as a catalyst for the oxidation of glycerol to formic acid in a batch operation. Different synthetic methods for PVxMo supported on mesoporous silica were compared. Detailed characterizations of the final products were carried out by N2 adsorption and desorption, XRD, HR-TEM, SEM, ICP-OES, XANES, NH3-TPD, and FTIR to identify the chemical properties and the porous structure of silica-supported PVxMo, as well as the strong interactions between PVxMo with the silica skeleton. These critical properties explain the bifunctionality of silica-supported PVxMo as a catalyst for the selective oxidation of glycerol to formic acid with standing stability. Keywords: Glycerol, Formic acid, SBA-15, V-substituted heteropoly acid

Three crystalline truxene-based β-ketoenamine COF membranes (TFP-HETTA, TFP-HBTTA and TFP-HHTTA) are fabricated via a de novo monomer design approach to understand the fundamental correlations between pore structure and molecular separation performance. By introducing bulky alkyl groups into the truxene framework, the pore size of TFP-HETTA, TFP-HBTTA, and TFP-HHTTA are systematically tuned from 1.08 to 0.72 nm. Accordingly, the TFP-HETTA showed good water permeance of 47 L m−2 h−1 bar−1 along with a prominent rejection rate of Reactive Blue (RB, 800 Da) but less than 10% rejection rate of inorganic salts. In contrast, the TFP-HHTTA membrane with pore size of 0.72 nm can reject small dye molecules such as Safranin O (SO, 350 Da) and trivalent salts but with a moderate water permeance of 19 L m−2 h−1 bar−1. The pore-flow model rooted from the viscous flow could well fit the observed organic solvent nanofiltration results of all three COF membranes.

The high performance of perovskite solar cells was produced with the help of an electron transport layer (ETL) and hole transport layer. The film ETL (mesoporous (meso)-TiO2/carbon dot) boosted the efficiency of the perovskite solar cells. A perovskite cell was fabricated by a coating of carbon dot on a meso-TiO2 ETL. The fabricated meso-TiO2/carbon dot-based device has decreased the pin-holes of the perovskite film layer compared to the meso-TiO2-based device, which boosted 3% of the averaged PCE value of the devices. The UV–visible spectroscopy confirmed that the meso-TiO2/carbon dot ETL showed better absorbance, that is, absorbed more incident light than meso-TiO2 ETL to generate higher power conversion efficiency. Coating of carbon dot on meso-TiO2 reduced carrier recombination, and fadeaway of the perovskite film cracks. The X-ray diffraction spectra displayed the removal of the perovskite component after spin-coating of carbon dot to the meso-TiO2 ETL, indicating that the suppression of non-radiative recombination improves the device performance compared to meso-TiO2 ETL. The stability after four weeks on the performance of the device was improved to be 92% by depositing carbon dot on meso-TiO2 ETL compared to the meso-TiO2 ETL-based device (82%). Thus, the high-quality perovskite cell was fabricated by coating carbon dot on a meso-TiO2 ETL, because the electron transport between ETL and perovskite film layer was improved by the injection of electrons from carbon dot.

Advances in processing capabilities of computer clusters have allowed for the full modeling of organometallic complexes that previously would have been simplified to reduce computational cost. Increased feasibility of computational modeling offers new challenges, not only in terms of limitations of methods and theory, but attention should be paid to complexes that can exist in many conformations, as the appropriate choice of conformer may be easily overlooked. In this work a series of pincer complexes with isopropyl and cyclopentyl substituents have been chosen as examples to demonstrate the importance of conformational analysis. The complexes examined contain four isopropyl or cyclopentyl groups on phosphor atoms generating between 27 and 324 possible rotamers. The importance of conformational search in a mechanistic investigation is demonstrated with the CO2 insertion into a nickel hydride bond of POCOP iPr nickel hydride complex. Results show that the reaction energy profile can be both exergonic and endergonic depending on rotamer choice. Specifically, the POCOPiPr Ni-formato complex product of the CO2 insertion reaction had an energy difference between the lowest and highest energy rotamer as high as 16.8 kcal/mol. The significant energy differences between rotamers highlight the importance of thorough conformational analysis and should be taken into consideration when evaluating the energy profile of related reactions. Keywords: Conformational analysis, DFT, Pincer, Mechanism, Rotamers

Abstract Gravitational shockwaves are insensitive to higher-curvature corrections in the action. Recent work found that the OPE coefficients of lowest-twist multi-stress-tensor operators, computed holographically in a planar black hole background, are insensitive as well. In this paper, we analyze the relation between these two limits. We explicitly evaluate the two-point function on a shockwave background to all orders in a large central charge expansion. In the geodesic limit, we find that the ANEC exponentiates in the multi-stress-tensor sector. To compare with the black hole limit, we obtain a recursion relation for the lowest-twist products of two stress tensors in a spherical black hole background, letting us efficiently compute their OPE coefficients and prove their insensitivity to higher curvature terms. After resumming the lowest-twist stress-tensors and analytically continuing their contributions to the Regge limit, we find a perfect agreement with the shockwave computation. We also discuss the role of double-trace operators, global degenerate states, and multi-stress-tensor conformal blocks. These holographic results suggest the existence of a larger universal structure in higher-dimensional CFTs.

Abstract We probe the conformal block structure of a scalar four-point function in d ≥ 2 conformal field theories by including higher-order derivative terms in a bulk gravitational action. We consider a heavy-light four-point function as the boundary correlator at large central charge. Such a four-point function can be computed, on the gravity side, as a two-point function of the light operator in a black hole geometry created by the heavy operator. We consider analytically solving the corresponding scalar field equation in a near-boundary expansion and find that the multi-stress tensor conformal blocks are insensitive to the horizon boundary condition. The main result of this paper is that the lowest-twist operator product expansion (OPE) coefficients of the multi-stress tensor conformal blocks are universal: they are fixed by the dimension of the light operators and the ratio between the dimension of the heavy operator and the central charge C T . Neither supersymmetry nor unitary is assumed. Higher-twist coefficients, on the other hand, generally are not protected. A recursion relation allows us to efficiently compute universal lowest-twist coefficients. The universality result hints at the potential existence of a higher-dimensional Virasoro-like symmetry near the lightcone. While we largely focus on the planar black hole limit in this paper, we include some preliminary analysis of the spherical black hole case in an appendix.

Two-dimensional (2D) layered materials functionalized with monometallic or bimetallic dopants are excellent materials to fabricate clinically useful biosensors. Herein, we report the synthesis of ruthenium nanoparticles (RuNPs) and nickel molybdate nanorods (NiMoO4 NRs) functionalized porous graphitic carbon nitrides (PCN) for the fabrication of sensitive and selective biosensors for cardiac troponin I (cTn-I). A wet chemical synthesis route was designed to synthesize PCN-RuNPs and PCN-NiMoO4 NRs. Morphological, elemental, spectroscopic, and electrochemical investigations confirmed the successful formation of these materials. PCN-RuNPs and PCN-NiMoO4 NRs interfaces showed significantly enhanced electrochemically active surface areas, abundant sites for immobilizing bioreceptors, porosity, and excellent aptamer capturing capacity. Both PCN-RuNPs and PCN-NiMoO4 NRs materials were used to develop cTn-I sensitive biosensors, which showed a working range of 0.1–10,000 ng/mL and LODs of 70.0 pg/mL and 50.0 pg/mL, respectively. In addition, the biosensors were highly selective and practically applicable. The functionalized 2D PCN materials are thus potential candidates to develop biosensors for detecting acute myocardial infractions.

Summary: Chiral phosphoric acid-catalyzed highly enantioselective formal [3 + 2] cycloaddition reaction of azoalkenes with 3-vinylindoles has been established. Under mild conditions, the projected cycloaddition proceeded smoothly, affording a variety of 2,3-dihydropyrroles in high yields and excellent enantioselectivities, and also in a diastereospecific manner. As opposed to the common 4-atom synthons in the previous literature reports, azoalkenes served as 3-atom synthons. Besides, the observed selectivity was supported by primary theoretical calculation. The unique chemistry of azoalkenes disclosed herein will empower asymmetric synthesis of nitrogen-containing ring structural motifs in a broader context. : Organic Chemistry; Organic Synthesis; Physical Organic Chemistry Subject Areas: Organic Chemistry, Organic Synthesis, Physical Organic Chemistry

Abstract In the context of boundary conformal field theory, we investigate whether the boundary trace anomaly can depend on marginal directions in the presence of supersymmetry. Recently, it was found that a graphene-like non-supersymmetric conformal field theory with a four-dimensional bulk photon and a three-dimensional boundary electron has two boundary central charges that depend on an exactly marginal direction, namely the gauge coupling. In this work, we supersymmetrize this theory, paying special attention to the boundary terms required by supersymmetry. We study models with 4, 8, and 16 Poincaré supercharges in the bulk, half of which are broken by the boundary. In all cases, we find that at all orders in perturbation theory, the gauge coupling is not renormalized, providing strong evidence that these theories are boundary conformal field theories. Moreover, the boundary central charges depend on the coupling. One possible exception to this dependence on marginal directions is that the difference between the two charges is coupling independent at one-loop in the maximally supersymmetric case. In our analysis, a possible boundary Chern-Simons term is incorporated by a bulk θ-term.

Abstract We study a 6d model of a set of self-dual 2-form B-fields interacting with a non-abelian vector A-field which is restricted to a 5d subspace. One motivation is that if the gauge vector could be expressed in terms of the B-field or integrated out, this model could lead to an interacting theory of B-fields only. Treating the 5d gauge vector as a background field, we compute the divergent part of the corresponding one-loop effective action which has the (DF)2 + F 3 structure and compare it with similar contributions from other 6d fields. We also discuss a 4d analog of the non-abelian self-dual model, which turns out to be UV finite.

Axially chiral compounds are commonly found in nature. Here, the authors show the highly enantioselective construction of axially chiral biaryls via an N-heterocyclic carbenes-catalyzed [3+3] atroposelective annulation of ynals with cyclic 1,3-diones.

A bimetallic FeCu/alumina catalyst was prepared and characterized. It showed excellent catalytic activity to quantitatively convert polystyrene (PS) into aromatics at low temperatures. A clear goldish yellow liquid was produced at 250 °C in a batch reactor without distillation. A liquid yield of 66% in an inert environment was achieved without the formation of coke and gas by-products. An exposure time of 90 min. and a catalyst loading of 200 mg were considered as an optimum conditions to minimize the styrene re-polymerization. The gas chromatography/mass spectrometry (GC/MS) analysis confirms that the primary products are styrene, ethylbenzene, cumene, toluene and α-methylstyrene. Keywords: Polystyrene, Bimetallic, Low-temperature, Catalytic degradation

Abstract We consider the structure of current and stress tensor two-point functions in conformal field theory with a boundary. The main result of this paper is a relation between a boundary central charge and the coefficient of a displacement operator correlation function in the boundary limit. The boundary central charge under consideration is the coefficient of the product of the extrinsic curvature and the Weyl curvature in the conformal anomaly. Along the way, we describe several auxiliary results. Three of the more notable are as follows: (1) we give the bulk and boundary conformal blocks for the current two-point function; (2) we show that the structure of these current and stress tensor two-point functions is essentially universal for all free theories; (3) we introduce a class of interacting conformal field theories with boundary degrees of freedom, where the interactions are confined to the boundary. The most interesting example we consider can be thought of as the infrared fixed point of graphene. This particular interacting conformal model in four dimensions provides a counterexample of a previously conjectured relation between a boundary central charge and a bulk central charge. The model also demonstrates that the boundary central charge can change in response to marginal deformations.

A high-surface-area Cu electrode, fabricated by a simple electrochemical anodization-reduction method, exhibits high activity and selectivity for CO2 reduction at low overpotential in 0.1 M KHCO3 solution. A faradaic efficiency of 37% for HCOOH and 27% for CO production was achieved with the current density of 1.5 mA cm−2 at −0.64 V vs. RHE, much higher than that of polycrystalline Cu. The enhanced catalytic performance is a result of the formation of the high electrochemical active surface area and high density of preferred low-index facets. Keywords: CO2 reduction, Cu electrode, High-surface-area, High selectivity

Mechanistic insights into the selective C–H terminal activation of n-pentane with tungsten allyl nitrosyl complex reported by Legzdins were gained by employing density functional theory with B3LYP hybrid functional. Using Bader’s atom in molecules (AIM) analysis on the elementary steps of the hydrogen transfer process, TS1 and TS2, it was observed that the calculated H-transfer models were closely similar to Hall’s metal-assisted σ-bond metathesis through bond critical point (BCP) comparisons. One distinguishable feature was the fact that the formal oxidation state of the W changed in the concerted H-transfer process. To better differentiate, we term these processes as ‘Formal Reductive Hydrogen Transfer’ (FRHT) for TS1 and ‘Formal Oxidative Hydrogen Transfer’ (FOHT) for TS2.

Hierarchical, nanoporous graphitic membranes are synthetically challenging yet attractive materials, due to their structural integrity. Here, the authors fabricate freestanding, porous carbon membranes with single-crystal-like graphitic order which serve as water splitting electrocatalysts upon cobalt doping.

Aluminum complexes containing [RP(O)(2-O-3,5-tBu2C6H2)2]2− [R = tBu (3a), Ph (3b)] have been synthesized, structurally characterized, and their reactivity studied in comparison with those of their [RP(2-O-3,5-tBu2C6H2)2]2− [R = tBu (2a), Ph (2b)] analogs. Treating AlMe3 with one equiv of H2[3a-b] in THF at 0°C affords quantitatively [3a-b]AlMe, subsequent reactions of which with benzyl alcohol in THF at 25°C generate {[3a-b]Al(μ2-OCH2Ph)}2. The methyl [3a-b]AlMe and the benzyloxide {[3a-b]Al(μ2-OCH2Ph)}2 are all active for catalytic ring-opening polymerization (ROP) of ε-caprolactone and rac-lactide (rac-LA). Controlled experiments reveal that {[3a]Al(μ2-OCH2Ph)}2 is competent in living polymerization. Kinetic studies indicate that [3a]AlMe, in the presence of benzyl alcohol, catalyzes ROP of rac-LA at a rate faster than [3b]AlMe and [2a]AlMe(THF) by a factor of 1.8 and 23.6, respectively, highlighting the profound reactivity enhancement in ROP catalysis by varying the P-substituents of these biphenolate complexes of aluminum.

A highly efficient method for the synthesis of α-halocarbonyl compounds has been achieved via selective monobromination of aromatic and aliphatic carbonyl compounds with N-bromosuccinimide catalyzed by p-toluenesulfonic acid under microwave irradiation within 30 min.