Optical neural ordinary differential equations.

Increasing the layer number of on-chip photonic neural networks (PNNs) is essential to improve its model performance. However, the successive cascading of network hidden layers results in larger integrated photonic chip areas. To address this issue, we propose the optical neural ordinary differential equations (ON-ODEs) architecture that parameterizes the continuous dynamics of hidden layers with optical ODE solvers. The ON-ODE comprises the PNNs followed by the photonic integrator and optical feedback loop, which can be configured to represent residual neural networks (ResNets) and implement the function of recurrent neural networks with effectively reduced chip area occupancy. For the interference-based optoelectronic nonlinear hidden layer, the numerical experiments demonstrate that the single hidden layer ON-ODE can achieve approximately the same accuracy as the two-layer optical ResNets in image classification tasks. In addition, the ON-ODE improves the model classification accuracy for the diffraction-based all-optical linear hidden layer. The time-dependent dynamics property of ON-ODE is further applied for trajectory prediction with high accuracy.

A Smart Nanoreactor Based on an O2-Economized Dual Energy Inhibition Strategy Armed with Dual Multi-stimuli-Responsive "Doorkeepers" for Enhanced CDT/PTT of Rheumatoid Arthritis.

Activated fibroblast-like synovial (FLS) cells are regarded as an important target for rheumatoid arthritis (RA) treatment via starvation therapy mediated by glucose oxidase (GOx). However, the hypoxic RA-FLS environment greatly reduces the oxidation process of glucose and leads to a poor therapeutic effect of the GOx-based starvation therapy. In this work, we designed a hollow mesoporous copper sulfide nanoparticles (CuS NPs)-based smart GOx/atovaquone (ATO) codelivery system (named as V-HAGC) targeting RA-FLS cells to realize a O2-economized dual energy inhibition strategy to solve the limitation of GOx-based starvation therapy. V-HAGC armed with dual multi-stimuli-responsive "doorkeepers" can guard drugs intelligently. Once under the stimulation of photothermal and acidic conditions at the targeted area, the dual intelligent responsive "doors" would orderly open to realize the controllable release of drugs. Besides, the efficacy of V-HAGC would be much improved by the additional chemodynamic therapy (CDT) and photothermal therapy (PTT) stimulated by CuS NPs. Meanwhile, the upregulated H2O2 and acid levels by starvation therapy would promote the Fenton-like reaction of CuS NPs under O2-economized dual energy inhibition, which could enhance the PTT and CDT efficacy as well. In vitro and in vivo evaluations revealed V-HAGC with much improved efficacy of this combination therapy for RA. In general, the smart V-HAGC based on the O2-economized dual energy inhibition strategy combined with enhanced CDT and PTT has the potential to be an alternative methodology in the treatment of RA.

Plasma Spray vs. Electrochemical Deposition: Toward a Better Osteogenic Effect of Hydroxyapatite Coatings on 3D-Printed Titanium Scaffolds.

Surface modification of three-dimensional (3D)-printed titanium (Ti) scaffolds with hydroxyapatite (HA) has been a research hotspot in biomedical engineering. However, unlike HA coatings on a plain surface, 3D-printed Ti scaffolds have inherent porous structures that influence the characteristics of HA coatings and osteointegration. In the present study, HA coatings were successfully fabricated on 3D-printed Ti scaffolds using plasma spray and electrochemical deposition, named plasma sprayed HA (PSHA) and electrochemically deposited HA (EDHA), respectively. Compared to EDHA scaffolds, HA coatings on PSHA scaffolds were smooth and continuous. In vitro cell studies confirmed that PSHA scaffolds have better potential to promote bone mesenchymal stem cell adhesion, proliferation, and osteogenic differentiation than EDHA scaffolds in the early and late stages. Moreover, in vivo studies showed that PSHA scaffolds were endowed with superior bone repair capacity. Although the EDHA technology is simpler and more controllable, its limitation due to the crystalline and HA structures needs to be improved in the future. Thus, we believe that plasma spray is a better choice for fabricating HA coatings on implanted scaffolds, which may become a promising method for treating bone defects.

A multifunctional nano-therapeutic platform based on octahedral yolk-shell Au NR@CuS: Photothermal/photodynamic and targeted drug delivery tri-combined therapy for rheumatoid arthritis.

Rheumatoid arthritis (RA) is a common chronic autoimmune disease that results from synovial hyperplasia. The hyperplasia of synovium directly degrades cartilage by secreting matrix-degrading enzymes and inducing cartilage degradation and even loss of joint function. In this study, a metal/semiconductor composite, octahedral copper sulfide shell, and gold nanorod core (Au NR@CuS) is designed for, photothermal therapy (PTT), photodynamic therapy (PDT), and chemotherapy (CT) combination therapy for RA to remove hyperplasia of the synovium. Upon laser irradiation, the coupling of the local surface electromagnetic field improves the electromagnetic field of the Au NR core and the absorption of light of the CuS shell, whereby the photothermal effect is enhanced. Due to the Fenton-like reactions and the integration of Au NR and CuS semiconductor photocatalyst inhibits hole recombination and provides a reaction site for photocatalysis, which introduces additional •OH to photodynamics therapy. In addition, the large octahedral void space in Au NR@CuS NPs can be used for loading a high quantity of drugs for chemotherapy, and modified with vasoactive intestinal peptide and hyaluronic acid (HA) formation VIP-HA-Au NR@CuS NPs to target synovial cells in RA. Under combination therapy, VIP-HA-Au NR@CuS NPs were shown to effectively inhibit the synovial cells and the edema degree of the CIA mouse was alleviated apparently. Both in vitro and in vivo studies indicate that the VIP-HA-Au NR@CuS NPs can provide a potential possibility for the treatment of RA.

Anisotropic Truncated Octahedral Au with Pt Deposition on Arris for Localized Surface Plasmon Resonance-Enhanced Photothermal and Photodynamic Therapy of Osteosarcoma.

The multifunctional combined nanoplatform has a wide application prospect in the synergistic treatment of cancer. Nevertheless, the traditional treatment of phototherapy is limited by the catalytic nanomaterial itself, so the effect is not satisfactory. Here, the arris of the anisotropic truncated octahedral Au (TOh Au) was coated with noble metal Pt to form a spatial separation structure, which enhanced the local surface plasmonic resonance and thus boosted the photocatalytic effect. In this system, the highly efficient photocatalysis provides a strong guarantee for oncotherapy. On the one hand, the structure of arris deposition adequately improves the efficiency of photothermal conversion, which substantially improves the effectiveness of photothermal therapy. On the other hand, in situ oxygen production of Pt ameliorates tumor hypoxia, and through the O2 self-production and sales mode, the growth and development of tumor were inhibited. Meanwhile, under the enhanced photocatalysis, more O2 were produced, which greatly evolved the treatment effect of photodynamic therapy. In the end, the addition of hyaluronic acid can specifically target osteosarcoma cells while improving the retention time and biocompatibility of the material in the body. Thus, the nanocomposite shows superexcellent synergistic enhancement of photothermal conversion efficiency and photodynamic capability in vitro and in vivo, which provides a potential possibility for osteosarcoma cure.

Three-Dimensional High-Porosity Chitosan/Honeycomb Porous Carbon/Hydroxyapatite Scaffold with Enhanced Osteoinductivity for Bone Regeneration.

Three-dimensional honeycomb porous carbon (HPC) has attracted increasing attention in bioengineering due to excellent mechanical properties and a high surface-to-volume ratio. In this paper, a three-dimensional chitosan (CS)/honeycomb porous carbon/hydroxyapatite composite was prepared by nano-sized hydroxyapatite (nHA) on the HPC surface in situ deposition, dissolved in chitosan solution, and vacuum freeze-dried. The structure and composition of CS/HPC/nHA were characterized by scanning electron microscopy, transmission electron miscroscopy, Fourier transform infrared, and X-ray photoelectron spectroscopy, and the porosity, swelling ratio, and mechanical properties of the scaffold were also tested. The as-prepared scaffolds possess hierarchical pores and organic-inorganic components, which are similar in composition and structure to bone tissues. The synthesized composite scaffold has high porosity and a certain mechanical strength. By culturing mouse bone marrow mesenchymal stem cells on the surface of the scaffold, it was confirmed that the scaffold facilitated its growth and promoted its differentiation into the osteogenesis direction. In vivo experiments further demonstrate that the CS/HPC/nHA composite scaffold has a significant advantage in promoting bone formation in the bone defect area. All the results suggested that the CS/HPC/nHA scaffolds have great application prospect in bone tissue engineering.

Bioactive Three-Dimensional Graphene Oxide Foam/Polydimethylsiloxane/Zinc Silicate Scaffolds with Enhanced Osteoinductivity for Bone Regeneration.

Nanocomposite scaffold materials have shown great prospect in promoting bone integration and bone regeneration. A three-dimensional graphene oxide foam/polydimethylsiloxane/zinc silicate (GF/PDMS/ZS) scaffold for bone tissue engineering was synthesized via dip coating and hydrothermal synthesis processes, resulting in the interconnected macroporous structure. The scaffold was characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and thermogravimetric (TG) analysis. The result showed that scaffolds exhibiting a porous characteristic had organic-inorganic components similar to natural bone tissue. Moreover, the scaffolds possessed suitable pore size, high porosity, and good mechanical properties. In vitro experiments with mouse bone marrow mesenchymal stem cells (mBMSCs) revealed that the composite scaffold not only has great biocompatibility but also has the ability to induce mBMSC proliferation and preferential osteogentic differentiation. Thereafter, the expression of critical genes, ALP, RUNX2, VEGFA, and OPN, was activated. In vivo analysis of critical bone defect in rabbits demonstrated superior bone formation in defect sites in the GF/PDMS/ZS scaffold group at 12 weeks of post implantation without no significant inflammatory response. All the results validated that the GF/PDMS/ZS scaffold is a promising alternative for applications in bone regeneration.

Two threefold interpenetrated two-dimensional frameworks based on a flexible imidazole-containing ligand and benzene-1,4-dicarboxylate.

The open-chain polyether-bridged flexible ligand 1,2-bis[2-(1H-1,3-imidazol-1-ylmethyl)phenoxy]ethane (L) has been used to create two two-dimensional coordination polymers under hydrothermal reaction of L with Cd(II) or Co(II), in the presence of benzene-1,4-dicarboxylic acid (H(2)bdc). In poly[[(µ(2)-benzene-1,4-dicarboxylato){µ-1,2-bis[2-(1H-1,3-imidazol-1-ylmethyl)phenoxy]ethane}cadmium(II)] dihydrate], {[Cd(C(8)H(4)O(4))(C(22)H(22)N(4)O(2))]·2H(2)O}(n), (I), and the cobalt(II) analogue {[Co(C(8)H(4)O(4))(C(22)H(22)N(4)O(2))]·2H(2)O}(n), (II), the Cd(II) and Co(II) cations are six-coordinated by four carboxylate O atoms from two different bdc(2-) dianions in a chelating mode and two N atoms from two distinct L ligands. The metal ions, bdc(2-) dianions and L ligands each sit across crystallographic twofold axes. The bdc(2-) coordination mode and the coordinating orientation of the L ligand play an important role in constructing the novel two-dimensional framework. Complexes (I) and (II) are threefold interpenetrated two-dimensional frameworks; their structures are almost isomorphous, while the bond lengths, angles and hydrogen bonds are different in (I) and (II).

Bis(µ-2-{5-[(pyridin-4-ylmethyl)sulfanyl]-1,3,4-oxadiazol-2-yl}phenolato)bis[(acetylacetonato)copper(II)]: a novel binuclear metallocycle.

The new asymmetric ligand 2-{5-[(pyridin-4-ylmethyl)sulfanyl]-1,3,4-oxadiazol-3-yl}phenol (HL) has been used to synthesize the novel discrete title binuclear metallocycle, [Cu(2)(C(14)H(10)N(3)O(2)S)(2)(C(5)H(7)O(2))(2)] or Cu(2)L(2)(acac)(2) (acac is acetylacetonate). Each Cu(II) centre is five-coordinate and adopts a square-pyramidal geometry. Two ligands are connected by two Cu(II) cations to form the dinuclear metallocycle, which lies across a crystallographic inversion centre. Discrete molecules are linked into a two-dimensional structure through weak Cu···S, C-H···π and π-π interactions.

Synthesis and characterization of new coordination polymers with tunable luminescent properties generated from bent 1,2,4-triazole-bridged N,N'-dioxides and Ln(III) salts.

A new bent 1,2,4-triazole-bridged N,N'-dioxide ligand, namely, 3,5-bis(3-pyridyl-N-oxide)-4-amino-1,2,4-triazole (L2), was designed and synthesized by the oxidation of 3,5-bis(3-pyridyl)-4-amino-1,2,4-triazole with H(2)O(2) in the presence of HOAc at ambient temperatures. Eleven Ln(III)-based coordination polymers have been successfully prepared by the solution reactions of L2 with various Ln(III)-perchlorates. The structures of these new Ln(III) polymers clearly reflect the effect of the lanthanide contraction. Compounds 1-6 feature a two-dimensional net, in which the Ln(III) atoms adopt a nine-coordinate {LnO(9)} sphere due to their larger ionic radii, whereas the Ln(III) centers in the one-dimensional double-stranded chains of 7-11 with smaller ionic radii lie in a {LnO(8)} coordination environment. In addition, the tunable emission intensity was realized on 7 by controlling the type of the involved counterion on the basis of a reversible solid-state anion exchange. Such reversible solid-state anion exchange might provide an alternative approach to tuning the luminescence.

Cocrystallization of two tautomers: 4-(1-{[4-(dimethylamino)benzylidene]hydrazono}ethyl)benzene-1,3-diol and 6-[(E)-1-{[4-(dimethylamino)benzylidene]hydrazino}ethylidene]-3-hydroxycyclohexa-2,4-dien-1-one (1/1).

Two different tautomeric forms of a new Schiff base, C(17)H(19)N(3)O(2).C(17)H(19)N(3)O(2), are present in the crystal in a 1:1 ratio, namely the enol-imine form 4-(1-{[4-(dimethylamino)benzylidene]hydrazono}ethyl)benzene-1,3-diol and the keto-amine form 6-[(E)-1-{[4-(dimethylamino)benzylidene]hydrazino}ethylidene]-3-hydroxycyclohexa-2,4-dien-1-one. The tautomers are formed by proton transfer between the hydroxy O atom and the imine N atom and are hydrogen bonded to each other to form a one-dimensional zigzag chain along the crystallographic b axis via intermolecular hydrogen bonds.

Self-inclusion structure of 5,11,17,23-tetrakis(azidomethyl)-25,26,27,28-tetrahydroxycalix[4]arene, and 5,11,17,23-tetra-tert-butyl-25,27-bis(chloroacetoxy)-26,28-bis(2-pyridylmethoxy)calix[4]arene.

In the structures of the two title calix[4]arene derivatives, C(32)H(28)N(12)O(4), (I), and C(60)H(68)Cl(2)N(2)O(6), (II), compound (I) adopts an open-cone conformation in which there are four intramolecular O-H...O hydrogen bonds, while compound (II) adopts a distorted chalice conformation where the two pendant pyridyl rings, one of which is disordered, are almost mutually perpendicular, with an interplanar angle of 79.2 (2) or 71.4 (2) degrees . The dihedral angles between the virtual plane defined by the four bridging methylene C atoms and the phenol rings are 120.27 (7), 124.03 (6), 120.14 (8) and 128.25 (7) degrees for (I), and 95.99 (8), 135.93 (7), 97.21 (8) and 126.10 (8) degrees for (II). In the supramolecular structure of (I), pairs of molecules associate by self-inclusion, where one azide group of the molecule is inserted into the cavity of the inversion-related molecule, and the association is stabilized by weak intermolecular C-H...N hydrogen bonds and pi(N(3))-pi(aromatic) interactions. The molecular pairs are linked into a two-dimensional network by a combination of weak intermolecular C-H...N contacts. Each network is further connected to its neighbor to produce a three-dimensional framework via intersheet C-H...N hydrogen bonds. In the crystal packing of (II), the molecular components are linked into an infinite chain by intermolecular C-H...O hydrogen bonds. This study demonstrates the ability of calix[4]arene derivatives to form self-inclusion structures.

A novel three-dimensional framework constructed by 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole and infinite chains of hydrogen-bonded water molecules.

A novel three-dimensional framework of 2-[(1H-imidazol-1-yl)methyl]-1H-benzimidazole dihydrate, C(11)H(10)N(4).2H(2)O or L.2H(2)O, (I), in which L acts as both hydrogen-bond acceptor and donor in the supramolecular construction with water, has been obtained by self-assembly reaction of L with H(2)O. The two independent water molecules are hydrogen bonded alternately with each other to form a one-dimensional infinite zigzag water chain. These water chains are linked by the benzimidazole molecules into a three-dimensional framework, in which each organic molecule is hydrogen bonded by three water molecules. This study shows that the diversity of hydrogen-bonded patterns plays a crucial role in the formation of the three-dimensional framework. More significantly, as water molecules are important in contributing to the conformation, stability, function and dynamics of biomacromolecules, the infinite chains of hydrogen-bonded water molecules seen in (I) may be a useful model for water in other chemical and biological processes.

A binuclear Cu(II) metallacycle capable of discerning between pyrazine and its different methyl-substituted derivatives based on reversible intracage metal-ligand binding.

Squashy cage: A flexible, spongelike, and reversible metal-binding Cu(2)L(2) cage that can adjust its internal space in response to pyrazine and its derivatives based on a recognition sequence of pyrazine, 2,5-dimethylpyrazine, and 2-methylpyrazine (see figure) is described.

3,5-Bis(4-methoxy-phen-yl)-1H-1,2,4-triazole monohydrate.

In the title compound, C(16)H(15)N(3)O(2)·H(2)O, the two benzene rings and the triazole ring lie almost in the same plane, the triazole ring forming dihedral angles of 5.07 (9) and 5.80 (8)° with the benzene rings. In the crystal, there are three relatively strong inter-molecular O-H⋯N and N-H⋯O hydrogen bonds, which lead to the formation of a one-dimensional double chain running parallel to the a axis. Weak π-π inter-actions between the benzene rings of neighboring chains with a centroid-centroid distance of 3.893 (4) Šresult in the formation of layers parallel to the ac plane.

Bis{µ-2,5-bis-[4-(2-pyridylmethyl-amino)phen-yl]-1,3,4-oxadiazole}bis-[dichlorido-mercury(II)].

In the title centrosymmetric compound, [Hg(2)Cl(4)(C(26)H(22)N(6)O)(2)], each Hg(II) center adopts a distorted HgN(3)Cl(2) trigonal bipyramidal coordination geometry, formed by two pyridine N atoms, one imine N atom and two chloride anions. Within the organic ligand, the oxadiazole ring is nearly coplanar with the two benzene rings [dihedral angles = 5.9 (4) and 6.5 (4)°] and nearly perpendicular to the two pyridine rings with the same dihedral angle of 77.4 (4)°. The two organic ligands bridge two Hg(II) ions to form the macrocyclic complex. Inter-molecular N-H⋯Cl and N-H⋯N hydrogen bonding helps to stabilize the crystal structure.

4-[5-(4-Pyrid-yl)-1,3,4-oxadiazol-2-yl]pyridine N-oxide-isophthalic acid (1/1).

The title compound, C(12)H(8)N(4)O(2)·C(8)H(6)O(4), was synthesized from 4-[5-(4-pyrid-yl)-1,3,4-oxadiazol-2-yl]pyridine N-oxide and isophthalic acid. The two mol-ecules are linked through O-H⋯O and O-H⋯N hydrogen bonds. Weak intra-molecular π-π inter-actions between the two hydrogen-bonded chains result in the formation a one-dimensional supra-molecular curved tape (the face-to-face distance between the pyridine N-oxide ring and the benzene ring is 3.7 Å).