Inversion using a new low-dimensional representation of complex binary geological media based on a deep neural network

Efficient and high-fidelity prior sampling and inversion for complex geological media is still a largely unsolved challenge. Here, we use a deep neural network of the variational autoencoder type to construct a parametric low-dimensional base model parameterization of complex binary geological media. For inversion purposes, it has the attractive feature that random draws from an uncorrelated standard normal distribution yield model realizations with spatial characteristics that are in agreement with the training set. In comparison with the most commonly used parametric representations in probabilistic inversion, we find that our dimensionality reduction (DR) approach outperforms principle component analysis (PCA), optimization-PCA (OPCA) and discrete cosine transform (DCT) DR techniques for unconditional geostatistical simulation of a channelized prior model. For the considered examples, important compression ratios (200 - 500) are achieved. Given that the construction of our parameterization requires a training set of several tens of thousands of prior model realizations, our DR approach is more suited for probabilistic (or deterministic) inversion than for unconditional (or point-conditioned) geostatistical simulation. Probabilistic inversions of 2D steady-state and 3D transient hydraulic tomography data are used to demonstrate the DR-based inversion. For the 2D case study, the performance is superior compared to current state-of-the-art multiple-point statistics inversion by sequential geostatistical resampling (SGR). Inversion results for the 3D application are also encouraging

Highly <i>Cis</i>-1,4-Selective Living Polymerization of 3‑Methylenehepta-1,6-diene and Its Subsequent Thiol–Ene Reaction: An Efficient Approach to Functionalized Diene-Based Elastomer

Living polymerization of 3-methylenehepta-1,6-diene (MHD) catalyzed by bis­(phosphino)­carbazoleide-ligated yttrium alkyl complex afforded a new product bearing pendant terminal vinyl groups with high stereotacticity (<i>cis</i>-1,4-selectivity up to 98.5%), proved by the NMR (¹H, ¹³C, and 1D ROESY) spectroscopic analyses, which demonstrates overwhelmingly favorable chemoselectivity toward conjugated diene over α-olefin moieties. High <i>cis</i>-1,4 random copolymers of MHD and isoprene could also be obtained with pendant vinyl groups ranging from 10% to 90%. These vinyl groups in every chain unit can be cleanly and quantitatively converted into various functionalities via light-mediated thiol–ene reaction, resulting in homo- and copolymers of various functional butadiene derivatives, which display versatile thermal properties

<i></i>β-Diketiminato Rare-Earth Metal Complexes. Structures, Catalysis, and Active Species for Highly <i>cis</i>-1,4-Selective Polymerization of Isoprene

Lithiation of the β-diketimines (2,6-C6H3R2)NHC(Me)CHC(Me)N(2,6-C6H3R2) (R = Me (HL1), Et (HL2)) by nBuLi was followed by metathesis reaction with LnCl3(THF)x and Y(BH4)3(THF)2 to afford the corresponding complexes L1LnCl2(THF)2 (Ln = Gd (1), Nd (3), Dy (4), Er (5), Y (6)), L2GdCl2(THF)2 (2), and L1Y(BH4)2(THF) (8), respectively. Treatment of neutral HL1 with Y(CH2SiMe3)3(THF)2 generated the bis(alkyl) complex 7, L1Y(CH2SiMe3)2(THF). Upon activation with [PhNHMe2][B(C6F5)4] and AliBu3, complex 6 showed the highest cis-1,4 selectivity (99.3%, Tp = 0 °C) toward the polymerization of isoprene, while complex 7 had a comparatively low cis-1,4 selectivity, and in contrast, complex 8 was completely inert. The influences of the ortho substituents of the N-aryl rings of the ligands, the types of central metals and cocatalysts, and addition sequence of the catalyst components had been thoroughly investigated. By means of X-ray diffraction and 1H NMR spectroscopy analyses, the intermediates arising from the stoichiometric reactions among the catalyst components and the probable active species were elucidated, which facilitates further investigation of the mechanism for diene polymerization

Highly 3,4-Selective Polymerization of Isoprene with NPN Ligand Stabilized Rare-Earth Metal Bis(alkyl)s. Structures and Performances

Deprotonation of Ar1NHPPh2NAr2 (H[NPN]n, n = 1−10) by Ln(CH2SiMe3)3(THF)2 (Ln = Lu, Y, Sc, Er) generated a series of rare-earth metal bis(alkyl) complexes [NPN]nLn(CH2SiMe3)2(THF)2 (1−10), which under activation with [Ph3C][B(C6F5)4] and AliBu3 were tested for isoprene polymerization. The correlation between catalytic performances and molecular structures of the complexes has been investigated. Complexes 1−5 and 8, where Ar1 is nonsubstituted or ortho-alkyl-substituted phenyl, adopt trigonal-bipyramidal geometry. The Ar1 and Ar2 rings are perpendicular in 1−4 and 8 but parallel in 5. When Ar1 is pyridyl, the resultant lutetium and yttrium complexes 9a and 9b adopt tetragonal geometry with the ligand coordinating to the metal ions in a N,N,N-tridentate mode, whereas in the scandium analogue 9c, the ligand coordinates to the Sc3+ ion in a N,N-bidentate mode. These structural characteristics endow the complexes with versatile catalytic performances. With increase of the steric bulkiness of the ortho-substituents Ar1 and Ar2, the 3,4-selectivity increased stepwise from 81.6% for lutetium complex 1 to 96.8% for lutetium complex 6 and to 97.8% for lutetium complex 7a. However, further increase of the steric bulk of the ligand led to a slight drop of 3,4-selectivity for the attached complex 5 (95.1%). When the smaller scandium ion was employed, the corresponding complex 7c provided 98.1% 3,4-selectivity, which reached 99.4% when the polymerization was performed at −20 °C, and the polymerization had quasi-living characteristics. Complexes 9a and 9b, containing an electron-donating ligand, gave higher 3,4-selectivities (85.0% vs 85.5%) than those attached to electron-withdrawing ligands 9c (33%) and 10 (77%)

<i></i>β-Diketiminato Rare-Earth Metal Complexes. Structures, Catalysis, and Active Species for Highly <i>cis</i>-1,4-Selective Polymerization of Isoprene

Lithiation of the β-diketimines (2,6-C6H3R2)NHC(Me)CHC(Me)N(2,6-C6H3R2) (R = Me (HL1), Et (HL2)) by nBuLi was followed by metathesis reaction with LnCl3(THF)x and Y(BH4)3(THF)2 to afford the corresponding complexes L1LnCl2(THF)2 (Ln = Gd (1), Nd (3), Dy (4), Er (5), Y (6)), L2GdCl2(THF)2 (2), and L1Y(BH4)2(THF) (8), respectively. Treatment of neutral HL1 with Y(CH2SiMe3)3(THF)2 generated the bis(alkyl) complex 7, L1Y(CH2SiMe3)2(THF). Upon activation with [PhNHMe2][B(C6F5)4] and AliBu3, complex 6 showed the highest cis-1,4 selectivity (99.3%, Tp = 0 °C) toward the polymerization of isoprene, while complex 7 had a comparatively low cis-1,4 selectivity, and in contrast, complex 8 was completely inert. The influences of the ortho substituents of the N-aryl rings of the ligands, the types of central metals and cocatalysts, and addition sequence of the catalyst components had been thoroughly investigated. By means of X-ray diffraction and 1H NMR spectroscopy analyses, the intermediates arising from the stoichiometric reactions among the catalyst components and the probable active species were elucidated, which facilitates further investigation of the mechanism for diene polymerization

Highly 3,4-Selective Polymerization of Isoprene with NPN Ligand Stabilized Rare-Earth Metal Bis(alkyl)s. Structures and Performances

Deprotonation of Ar1NHPPh2NAr2 (H[NPN]n, n = 1−10) by Ln(CH2SiMe3)3(THF)2 (Ln = Lu, Y, Sc, Er) generated a series of rare-earth metal bis(alkyl) complexes [NPN]nLn(CH2SiMe3)2(THF)2 (1−10), which under activation with [Ph3C][B(C6F5)4] and AliBu3 were tested for isoprene polymerization. The correlation between catalytic performances and molecular structures of the complexes has been investigated. Complexes 1−5 and 8, where Ar1 is nonsubstituted or ortho-alkyl-substituted phenyl, adopt trigonal-bipyramidal geometry. The Ar1 and Ar2 rings are perpendicular in 1−4 and 8 but parallel in 5. When Ar1 is pyridyl, the resultant lutetium and yttrium complexes 9a and 9b adopt tetragonal geometry with the ligand coordinating to the metal ions in a N,N,N-tridentate mode, whereas in the scandium analogue 9c, the ligand coordinates to the Sc3+ ion in a N,N-bidentate mode. These structural characteristics endow the complexes with versatile catalytic performances. With increase of the steric bulkiness of the ortho-substituents Ar1 and Ar2, the 3,4-selectivity increased stepwise from 81.6% for lutetium complex 1 to 96.8% for lutetium complex 6 and to 97.8% for lutetium complex 7a. However, further increase of the steric bulk of the ligand led to a slight drop of 3,4-selectivity for the attached complex 5 (95.1%). When the smaller scandium ion was employed, the corresponding complex 7c provided 98.1% 3,4-selectivity, which reached 99.4% when the polymerization was performed at −20 °C, and the polymerization had quasi-living characteristics. Complexes 9a and 9b, containing an electron-donating ligand, gave higher 3,4-selectivities (85.0% vs 85.5%) than those attached to electron-withdrawing ligands 9c (33%) and 10 (77%)

Nano CaCO₃ “Lysosomal Bombs” Enhance Chemotherapy Drug Efficacy via Rebalancing Tumor Intracellular pH

Successful delivery of drugs to the target site is half the battle against tumors as intracellular alkalization pH (pHi) microenvironments severely restricted the efficacy of chemotherapy drugs delivered into tumor cells. Herein, a redox-selective pH-triggered “lysosomal bomb” (DSA/CC-DOX) is developed based on vaterite calcium carbonate and disulfide-cross-linked sodium alginate (DSA) with doxorubicin (DOX) encapsulated. Benefiting from the acid-triggered volume expansion of CaCO3, DSA/CC-DOX NPs can act like a “lysosomal bomb” that rapidly tears the lysosomal membrane with the release of acidic inclusions and the loaded DOX, and then the alkalized pHi in human liver tumor cells (HepG2) can be decreased from 7.61 to 7.09, thus promoting the intracellular accumulation of DOX nearly 3 times more than the free drug. In addition, facilitated by the responsive break of the disulfide bond to GSH, the release of DOX in HepG2 is nearly 8 times that of human normal liver cell (LO2). Notably, DSA/CC-DOX treatment increased the tumor inhibition rate of free drug by 16% and effectively reduced the cardiotoxicity of DOX in the mouse H22 liver cancer model. Overall, acidifying the tumor intracellular environment is a prospective way to improve the antitumor capacity of chemotherapy drug

Legislative Documents

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Binuclear Rare-Earth-Metal Alkyl Complexes Ligated by Phenylene-Bridged β‑Diketiminate Ligands: Synthesis, Characterization, and Catalysis toward Isoprene Polymerization

Deprotonation of m-phenylene-bridged bis­(β-diketiminate) ligands (PBDIiPr-H2 = [2,6-iPr2C6H3NHC­(Me)­C­(H)­C­(Me)­N]2-(m-phenylene); PBDIEt-H2 = [2,6-Et2C6H3NHC­(Me)­C­(H)­C­(Me)­N]2-(m-phenylene); PBDIMe-H2 = [2,6-Me2C6H3NHC­(Me)­C­(H)­C­(Me)­N]2-(m-phenylene)) by rare-earth-metal tris­(alkyls) Ln­(CH2SiMe3)3(THF)2 (Ln = Y, Lu, Sc) gave a series of rare-earth-metal bis­(alkyl) complexes: PBDIiPr-[Y­(CH2SiMe3)2]2(THF)2 (1), PBDIEt-[Ln­(CH2SiMe3)2]2(THF)n (2a, Ln = Y, n = 2; 2b, Ln = Lu, n = 2; 2c, Ln = Sc, n = 1), and PBDIMe-[Y­(CH2SiMe3)2]2(THF)2 (3). All these complexes were fully characterized by NMR spectroscopy, X-ray diffraction, and elemental analyses, adopting binuclear structures with the two rare-earth-metal ions taking trans positions versus the phenyl ring. Complexes 1, 2a,b, and 3 coordinate two solvated THF molecules, while the scandium complex 2c incorporates only one THF molecule, owing to the steric crowding. Upon activation with 2 equiv of organoborate, the yttrium systems showed higher catalytic activity toward isoprene polymerization in comparison to those based on lutetium, and the scandium system was less active. Addition of aluminum alkyls to the above binary systems accelerated dramatically the polymerization rate irrespective of the central metal type through scavenging impurities in the systems and abstracting the solvated THF molecules in the precursors. The resultant polyisoprene had higher 3,4-regularity (20% vs 5%) as well as higher molecular weights in comparison with the mononuclear systems, which might be attributed to the steric bulky effect of the binuclear systems

Binuclear Rare-Earth-Metal Alkyl Complexes Ligated by Phenylene-Bridged β‑Diketiminate Ligands: Synthesis, Characterization, and Catalysis toward Isoprene Polymerization

Deprotonation of <i>m</i>-phenylene-bridged bis­(β-diketiminate) ligands (PBDI^<i>i</i>Pr-H₂ = [2,6-^<i>i</i>Pr₂C₆H₃NHC­(Me)­C­(H)­C­(Me)­N]₂-(<i>m</i>-phenylene); PBDI^Et-H₂ = [2,6-Et₂C₆H₃NHC­(Me)­C­(H)­C­(Me)­N]₂-(<i>m</i>-phenylene); PBDI^Me-H₂ = [2,6-Me₂C₆H₃NHC­(Me)­C­(H)­C­(Me)­N]₂-(<i>m</i>-phenylene)) by rare-earth-metal tris­(alkyls) Ln­(CH₂SiMe₃)₃(THF)₂ (Ln = Y, Lu, Sc) gave a series of rare-earth-metal bis­(alkyl) complexes: PBDI^<i>i</i>Pr-[Y­(CH₂SiMe₃)₂]₂(THF)₂ (<b>1</b>), PBDI^Et-[Ln­(CH₂SiMe₃)₂]₂(THF)_<i>n</i> (<b>2a</b>, Ln = Y, <i>n</i> = 2; <b>2b</b>, Ln = Lu, <i>n</i> = 2; <b>2c</b>, Ln = Sc, <i>n</i> = 1), and PBDI^Me-[Y­(CH₂SiMe₃)₂]₂(THF)₂ (<b>3</b>). All these complexes were fully characterized by NMR spectroscopy, X-ray diffraction, and elemental analyses, adopting binuclear structures with the two rare-earth-metal ions taking <i>trans</i> positions versus the phenyl ring. Complexes <b>1</b>, <b>2a</b>,<b>b</b>, and <b>3</b> coordinate two solvated THF molecules, while the scandium complex <b>2c</b> incorporates only one THF molecule, owing to the steric crowding. Upon activation with 2 equiv of organoborate, the yttrium systems showed higher catalytic activity toward isoprene polymerization in comparison to those based on lutetium, and the scandium system was less active. Addition of aluminum alkyls to the above binary systems accelerated dramatically the polymerization rate irrespective of the central metal type through scavenging impurities in the systems and abstracting the solvated THF molecules in the precursors. The resultant polyisoprene had higher 3,4-regularity (20% vs 5%) as well as higher molecular weights in comparison with the mononuclear systems, which might be attributed to the steric bulky effect of the binuclear systems