Preparation and study of a capillary electrochromatographic column prepared by conjugating ß-CD COFs and gold-poly glycidyl methacrylate nanoparticles.

A new enantioselective open-tubular capillary electrochromatography (OT-CEC) was developed employing ß-cyclodextrin covalent organic frameworks (ß-CD COFs) conjugated gold-poly glycidyl methacrylate nanoparticles (Au-PGMA NPs) as a stationary phase. The resulting coating layer on the inner wall of the fabricated capillary column was characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS), and electroosmotic flow (EOF) experiments. The performance of the fabricated capillary column was evaluated by CEC using enantiomers of seven model analytes, including two proton pump inhibitors (PPIs, omeprazole and tenatoprazole), three amino acids (AAs, tyrosine, phenylalanine, and tryptophan), and two fluoroquinolones (FQs, gatifloxacin and sparfloxacin). The influences of coating time, buffer concentration, buffer pH, and applied voltage on enantioseparation were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of seven analytes were fully resolved within 10 min with high resolutions of 3.03 to 5.25. The inter- to intra-day and column-to-column repeatabilities of the fabricated capillary column were lower than 4.26% RSD. Furthermore, molecular docking studies were performed based on the chiral fabricated column and as ligand isomers of analytes using Auto Dock Tools. The binding energies and interactions acquired from docking results of analytes supported the experimental data.

Photoinduced Phase Transition in Infinite-Layer Nickelates.

The quantum phase transition caused by regulating the electronic correlation in strongly correlated quantum materials has been a research hotspot in condensed matter science. Herein, a photon-induced quantum phase transition from the Kondo-Mott insulating state to the low temperature metallic one accompanying with the magnetoresistance changing from negative to positive in the infinite-layer NdNiO2 films is reported, where the antiferromagnetic coupling among the Ni1+ localized spins and the Kondo effect are effectively suppressed by manipulating the correlation of Ni-3d and Nd-5d electrons under the photoirradiation. Moreover, the critical temperature Tc of the superconducting-like transition exhibits a dome-shaped evolution with the maximum up to ≈42 K, and the electrons dominate the transport process proved by the Hall effect measurements. These findings not only make the photoinduction a promising way to control the quantum phase transition by manipulating the electronic correlation in Mott-like insulators, but also shed some light on the possibility of the superconducting in electron-doped nickelates.

Preparation of ß-cyclodextrin covalent organic framework-immobilized poly(glycidyl methacrylate) nanoparticle-coated open tubular capillary electrochromatography column for chiral separation.

A new enantioselective open-tubular capillary electrochromatography was developed employing poly(glycidyl methacrylate) nanoparticles/ß-cyclodextrin covalent organic frameworks chemically immobilized on the inner wall of the capillary as a stationary phase. A pretreated silica-fused capillary reacted with 3-aminopropyl-trimethoxysilane followed by poly(glycidyl methacrylate) nanoparticles and ß-cyclodextrin covalent organic frameworks through a ring-opening reaction. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The electroosmotic flow was studied to evaluate the variation of the immobilized columns. The chiral separation performance of the fabricated capillary columns was validated by the analysis of the four racemic proton pump inhibitors including lansoprazole, pantoprazole, tenatoprazole, and omeprazole. The influences of bonding concentration, bonding time, bonding temperature, buffer type and concentration, buffer pH, and applied voltage on the enantioseparation of four proton pump inhibitors were investigated. Good enantioseparation efficiencies were achieved for all enantiomers. In the optimum conditions, the enantiomers of four proton pump inhibitors were fully resolved within 10 min with high resolutions of 9.5-13.9. The column-to-column and inter- to intra-day repeatability of the fabricated capillary columns through relative standard deviation were found better than 9.54%, exhibiting satisfactory stability and repeatability of the fabricated capillary columns.

Biomechanical Evaluation of Rigid Interspinous Process Fixation Combined With Lumbar Interbody Fusion Using Hybrid Testing Protocol.

Rigid interspinous process fixation (RIPF) has been recently discussed as an alternative to pedicle screw fixation (PSF) for reducing trauma in lumbar interbody fusion (LIF) surgery. This study aimed to investigate biomechanics of the lumbar spine with RIPF, and also to compare biomechanical differences between two postoperative stages (before and after bony fusion). Based on an intact finite-element model of lumbosacral spine, the models of single-level LIF with RIPF or conventional PSF were developed and were computed for biomechanical responses to the moments of four physiological motions using hybrid testing protocol. It was found that compared with PSF, range of motion (ROM), intradiscal pressure (IDP), and facet joint forces (FJF) at adjacent segments of the surgical level for RIPF were decreased by up to 8.4%, 2.3%, and 16.8%, respectively, but ROM and endplate stress at the surgical segment were increased by up to 285.3% and 174.3%, respectively. The results of comparison between lumbar spine with RIPF before and after bony fusion showed that ROM and endplate stress at the surgical segment were decreased by up to 62.6% and 40.4%, respectively, when achieved to bony fusion. These findings suggest that lumbar spine with RIPF as compared to PSF has potential to decrease the risk of adjacent segment degeneration but might have lower stability of surgical segment and an increased risk of cage subsidence; When achieved bony fusion, it might be helpful for the lumbar spine with RIPF in increasing stability of surgical segment and reducing failure of bone contact with cage.

ß-Cyclodextrin covalent organic framework supported by polydopamine as stationary phases for electrochromatographic enantioseparation.

In this work, a new open-tubular capillary electrochromatography (OT-CEC) column was prepared using ß-cyclodextrin covalent organic framework (ß-CD COF) as a stationary phase. Polydopamine was used to assist fabrication of ß-CD COF on an inner wall of a fused-silica capillary. The coating layer on the capillary was characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). Electroosmotic flow (EOF) was also studied to evaluate the variation of the inner wall of immobilized columns. Furthermore, the chiral separation effectiveness of the fabricated capillary column was evaluated by CEC using enantiomers of several related proton pump inhibitors as model analytes, including omeprazole, lansoprazole, pantoprazole and tenatoprazole. The effects of bonding time and concentration of ß-CD COF, the type, concentration and pH of buffer, applied voltage were investigated to obtain satisfactory enantioselectivity. In the optimum conditions, the enantiomers of four analytes were resolved within 15 min with resolutions of 1.63-2.62. The relative standard deviation values for migration times and resolutions of the analytes representing intraday and interday were less than 6.75% and 4.24%, respectively. The results reveal that ß-CD COF has great potential as chiral-stationary phases for enantioseparation in CEC.

1,7-Di-tert-butyl-Substituted aza-BODIPYs by Low-Barrier Rotation to Enhance a Photothermal-Photodynamic Effect.

1,7-Di-tert-butyl-substituted aza-BODIPYs (tBu-azaBDP) were successfully obtained for the first time. The structures of tBu-azaBDP and Ph-azaBDP were confirmed by X-ray crystal analysis, and tBu-azaBDP 2 is more twisted than Ph-azaBDP 5. tBu-azaBDPs have significant photo-stability and enhanced water solubility. tBu-azaBDPs possess excellent optical properties, such as high molar extinction coefficients, broad full width half maxima, and large Stokes shifts, which is comparable to those of the parent dye Ph-azaBDP. Although the low-barrier rotation of the distal -tBu groups in tBu-azaBDPs results in low quantum yield, photothermal conversion efficiency and singlet oxygen generation ability of tBu-azaBDPs are more effective than those of Ph-azaBDP, which is highly desirable for a photothermal-photodynamic therapy agent.

Molecular reaction and dynamic mechanism of iodate reduction to molecular iodine by nitrogen(III) in aqueous solution.

This work studies the molecular reaction and dynamic mechanism of iodate reduction by nitrogen(III) in aqueous solution using the ab initio molecular dynamics (AIMD) method based on density functional theory (DFT). Two possible reaction pathways (without and with H+) are proposed. The thermodynamic parameters of the proposed reaction pathways are calculated. The theoretical calculation aspects of iodate reduction, including the atomic dipole moment corrected Hirshfeld population (ADCH) atomic charge values, the intrinsic reaction coordinate (IRC) curves, the calculated interaction regional indicator (IRI) isosurfaces with the corresponding sign(λ2)ρ scatter plots, electrostatic potential (ESP) analysis and molecular reaction dynamics are discussed in-depth. The results show that the reaction pathway with H+ is confirmed based on the Gibbs free energy analysis. The transition state proved that the iodate reduction with nitrous acid undergoes four steps according to oxygen-atom deprivation. The IRC curves describe the energy change of the chemical bonds of the reactant conformations in the four steps, with an energy reduction of 71.95, 69.35, 130.15, and 125.87 kJ mol-1, respectively. The ESP interpenetration diagram and IRI isosurfaces provide detailed information on the nucleophilicity and electrophilicity of the reactant conformations. By decreasing the O atom number in HIOx (x = 1, 2, 3), the maximum positive charge decreases, and the positive charge coverage area increases, thus resulting in energy reduction and consequently a more stable conformation. Molecular reaction dynamics analytical results indicated that a relatively stable status of the reactants of the four steps was achieved after around 200 fs, and that the HIO3-HNO2 reaction released the highest energy.

Preparation of a polydopamine/ß-cyclodextrin coated open tubular capillary electrochromatography column and application for enantioseparation of five proton pump inhibitors.

An open tubular capillary electrochromatography column was prepared by immobilizing ß-cyclodextrin on the inner wall of pretreated capillary via noncovalent adsorption of polydopamine. The resulting coating layer on the capillary was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Electroosmotic flow was studied to evaluate the variation of the immobilized columns. The prepared columns showed good chiral separation performance toward five proton pump inhibitors including lansoprazole, pantoprazole, tenatoprazole, rabeprazole, and omeprazole. The influences of ß-cyclodextrin concentration, coating time, buffer pH, buffer concentration, and applied voltage on separation were investigated. In the optimum conditions, the enantiomers of five analytes were fully resolved within 15 min with high resolutions of 4.57 to 8.13. The method was extensively validated in terms of accuracy, precision, and linearity and proved to be robust. The relative standard deviation values for migration times and peak areas of the analytes representing intraday and interday were less than 1.9 and 3.6%, respectively. Further, the polydopamine/ß-cyclodextrin coated capillary column could be successively used over 100 runs without showing significant decrease in the separation efficiency.

Effect of high-density lipoprotein on penile erection: A cross-sectional study.

Previous studies have shown that elevated levels of high-density lipoprotein (HDL) could inhibit penile erection, but the relationship between HDL and the erection of the penile tip or base has not been extensively researched. We investigated the effects of HDL on erection of the penile tip and base through a cross-sectional study of 113 patients with erectile dysfunction, using a cut-off score of ≤21 on the International Index of Erectile Function-5. The following patient data were collected: nocturnal penile tumescence; blood pressure; platelet count; platelet distribution width; mean platelet volume; plateletcrit; and levels of serum glucose, total cholesterol, triglyceride, HDL, and low-density lipoprotein. Univariate and multivariate analyses were used to assess the association between HDL levels and the erection of the penile tip and base. We confirmed that HDL had a beneficial effect on penile erectile function. We also found that when the HDL level exceeded the normal range, the change in HDL had a significant effect on the penile base. In addition, our study did not find any relationship between platelet parameters and erection of the penile tip or penile base.

[Biomechanical study of different approach for lumbar interbody fusion surgeries under vibration load].

The human spine injury and various lumbar spine diseases caused by vibration have attracted extensive attention at home and abroad. To explore the biomechanical characteristics of different approaches for lumbar interbody fusion surgery combined with an interspinous internal fixator, device for intervertebral assisted motion (DIAM), finite element models of anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF) and lateral lumbar interbody fusion (LLIF) are created by simulating clinical operation based on a three-dimensional finite element model of normal human whole lumbar spine. The fusion level is at L4-L5, and the DIAM is implanted between spinous process of L4 and L5. Transient dynamic analysis is conducted on the ALIF, TLIF and LLIF models, respectively, to compute and compare their stress responses to an axial cyclic load. The results show that compared with those in ALIF and TILF models, contact forces between endplate and cage are higher in LLIF model, where the von-Mises stress in endplate and DIAM is lower. This implies that the LLIF have a better biomechanical performance under vibration. After bony fusion between vertebrae, the endplate and DIAM stresses for all the three surgical models are decreased. It is expected that this study can provide references for selection of surgical approaches in the fusion surgery and vibration protection for the postsurgical lumbar spine.

Addition Reactions of Me3 SiCN with Aldehydes Catalyzed by Aluminum Complexes Containing in their Coordination Sphere O, S, and N Ligands.

The reaction of one equivalent of LAlH2 (1; L=HC(CMeNAr)2 , Ar=2,6-iPr2 C6 H3 , ß-diketiminate ligand) with two equivalents of 2-mercapto-4,6-dimethylpyrimidine hydrate resulted in LAl[(µ-S)(m-C4 N2 H)(CH2 )2 ]2 (2) in good yield. Similarly, when N-2-pyridylsalicylideneamine, N-(2,6-diisopropylphenyl)salicylaldimine, and ethyl 3-amino-4,5,6,7-tetrahydrobenzo[b]thiophene-2-carboxylate were used as starting materials, the corresponding products LAl[(µ-O)(o-C6 H4 )CN(C5 NH4 )]2 (3), LAlH[(µ-O)(o-C4 H4 )CN(2,6-iPr2 C6 H3 )] (4), and LAl[(µ-NH)(o-C8 SH8 )(COOC2 H5 )]2 (5) were isolated. Compounds 2-5 were characterized by (1) H and (13) C NMR spectroscopy as well as by single-crystal X-ray structural analysis. Surprisingly, compounds 2-5 exhibit good catalytic activity in addition reactions of aldehydes with trimethylsilyl cyanide (TMSCN).

Organocatalytic asymmetric Michael addition of α-alkylidene succinimides to nitrostyrenes.

A bifunctional squaramide-catalyzed asymmetric Michael addition reaction of α-alkylidene succinimides with nitrostyrenes and a nitrodiene has been developed. This organocatalytic asymmetric reaction provides easy access to functionalized succinimides with two contiguous stereocenters with a broad substrate scope. The desired succinimide derivatives were obtained in good to excellent yields (up to 98%) with high to excellent diastereoselectivities (up to >99 : 1 dr) and excellent enantioselectivities (up to 99% ee). This protocol provides a straightforward entry to functionalized chiral succinimide derivatives from simple starting materials.

Dual-wavelength Nd:YAG laser operation at 1319 and 1338 nm by direct pumping at 885 nm.

This paper presents a continuous wave and a Q-switched Nd:YAG laser pumped by diode laser at 885 nm. The maximum output power of the CW laser is 8.28 W with an absorbed slope efficiency of 35.01%. The Q-switching is achieved using a V³âº:YAG crystal as the saturable absorber. The maximum output power of the passively Q-switched laser is 3.55 W with an absorbed pumping power of 28.65 W operated with a dual wavelength at 1319 and 1338 nm. The shortest pulse widths of the Q-switched laser are 20.20 and 20.86 ns, with a maximum repetition rate of 64.10 kHz.

Q-switched 1329 nm Nd:CNGG laser.

We demonstrate a laser-diode-pumped Q-switched 1329 nm neodymium-doped calcium-niobium-gallium-garnet (Nd:CNGG) laser using a V:YAG crystal as a saturable absorber. An average output power of 353 mW and a repetition rate of 13.43 kHz for Q-switched pulses were obtained. The pulse width was from 124 to 151.4 ns under different pump powers. Output power of 685 mW was obtained without the V:YAG crystal inserted.

Highly radioiodine gas capture by 2-mercaptobenzimidazole-functionalized Bi/Mg oxide and effective iodine waste immobilization by etidronic-Bi2O3 complex.

The present work prepared a novel BiMgO-2MBD (X = 0.42) material for iodine vapor capture in temperature conditions related to spent nuclear fuel reprocessing and nuclear accidents. BiMgO-2MBD (X = 0.42) was synthesized by a solvothermal process and exhibited an exceptional ultrafast and high iodine uptake with a capacity of 4352.12 mg/g and 5147.08 mg/g after 5 h at 75 °C and 150 °C, respectively. The TGA analysis shows that Bi/Mg oxide substrate highly contributed to improving the thermal stability of the functionalized BiMgO-2MB (X = 0.42) as indicated by the weight losses of the material components of 3.77 wt%, 29.32 wt%, and 97.72 wt%, respectively for Bi/Mg oxide, BiMgO-2MBD, and 2-MBD. The material characterization and DFT calculations indicate that 2-MBD played a significant role towards improving iodine capture capacity. For long-term and safe waste disposal, a chemically durable waste form was made from etidronic acid and Bi2O3, and successfully immobilized the iodine-loaded wastes (I2 @BiMgO-2MBD) which exhibited a low normalized leaching rate of 1.098 × 10-6 g.m2/day for 7 days under the PCT-A method. In addition, BiMgO-2MBD (X = 0.42) showed an ability to be reused after several regeneration cycles. The comparison with previously reported materials shows that the current BiMgO-2MBD (X = 0.42) is the first functionalized metal oxide comparable to metal-organic and covalent organic frameworks for iodine uptake. BiMgO-2MBD (X = 0.42) shows promising results for practical applications in the gas phase capture of radioactive iodine.

Monophenylboryl aza-BODIPY with free rotation of the B-phenyl group for enhanced photothermal conversion.

Owing to the efficient non-radiative relaxation by the free rotation of the B-phenyl moiety, monophenyl substituted aza-BODIPY on the boron centre with near-infrared absorption has high photothermal conversion efficiency, which is highly desirable for a photothermal therapy agent.

Design and fabrication of a diffractive optical element as a spectrum-splitting solar concentrator for lateral multijunction solar cells.

We have designed a single thin planar diffractive optical element (DOE) based on the principle of diffractive optics to simultaneously split and concentrate the incident light into several energy ranges for lateral multijunction solar cells. A prototype with the maximum thickness of 6.95 µm and 32 quantized levels in depth was fabricated by photolithographic technology. The spectrum-splitting and concentrating performance of the prototype, which were measured quantitatively, show good agreement with the simulation results. As mass production of a DOE can be produced by imprint technology, our design provides a feasible means for low-cost, large-scale, and high-efficiency photovoltaic applications.

Effect of different fixation methods on biomechanical property of cervical vertebral body replacement and fusion.

BACKGROUND: The main purpose of this study was to examine the effect of different fixation methods (anterior fixation, self-stabilizing fixation and anterior-posterior fixation) on biomechanical property of vertebral body replacement and fusion. METHODS: Three finite element models of cervical vertebral body replacement and fusion were established. The implanted models included artificial vertebral body and fixation system, and the loads imposed on the models included 75 N compression load and 1 Nm moment load. FINDINGS: For anterior-posterior fixation, the cervical load was mainly transmitted by the posterior pedicle screw and rod (more than 50%), and the stress shielding problem was the most significant than the self-stabilizing and anterior fixation. Self-stabilizing fixation was more helpful to the fusion of implant and vertebrae, but the higher risk of vertebral body collapse was worthy of attention if the cervical spine with osteoporosis. The stress of bone was mainly concentrated around the screw hole. The maximum stress (20.03 MPa) was lower than the yield stress of cortical bone and the possibility of fracture around the fixation device of cervical spine was low. The anterior fixation could meet the requirement of vertebral body replacement and fusion, and the addition of posterior pedicle screws and rods might obtain better treatment in cases of severe spine injury or osteoporosis. INTERPRETATION: The findings of this study may provide guidance on clinical treatments for choosing more appropriate fixation methods for different patients.

Biomechanical responses of the human lumbar spine to vertical whole-body vibration in normal and osteoporotic conditions.

BACKGROUND: The prevalence of osteoporosis is continuing to escalate with an aging population. However, it remains unclear how biomechanical behavior of the lumbar spine is affected by osteoporosis under whole-body vibration, which is considered a significant risk factor for degenerative spinal disease and is typically present when driving a car. Accordingly, the objective of this study was to compare the spine biomechanical responses to vertical whole-body vibration between normal and osteoporotic conditions. METHODS: A three-dimensional finite-element model of the normal human lumbar spine-pelvis segment was developed using computed tomographic scans and was validated against experimental data. Osteoporotic condition was simulated by modifying material properties of bone tissues in the normal model. Transient dynamic analyses were conducted on the normal and osteoporotic models to compute deformation and stress in all lumbar motion segments. FINDINGS: When osteoporosis occurred, vibration amplitudes of the vertebral axial displacement, disc bulge, and disc stress were increased by 32.1-45.4%, 25.7-47.1% and 23.0-42.7%, respectively. In addition, it was found that for both the normal and osteoporotic models, the response values (disc bugle and disc stress) were higher in L4-L5 and L5-S1 intervertebral discs than in other discs. INTERPRETATION: Osteoporosis deteriorates the effect of whole-body vibration on lumbar spine, and the lower lumbar segments might have a higher likelihood of disc degeneration under whole-body vibration.

Aza-BODIPY with two efficacious fragments for NIR light-driven photothermal therapy by triggering cancer cell apoptosis.

The reasonable structure of aza-BODIPY renders it as an efficient photothermal reagent for photothermal therapy. Herein, we describe the design and synthesis of aza-BODIPY NMeBu with the free rotating tert-butyl group and the dimethylamino-substituted segment to promote the photothermal conversion via the excited state non-radiative transition. NMeBu was found to be the π-π stacking form in the unit cell based on X-ray analysis. NMeBu-NPs by self-assembly possessed a near-infrared absorption (λabs = 772 nm), and once activated by near-infrared light, the photothermal efficiency in aqueous solution can reach 49.3%. NMeBu-NPs can penetrate the cell and trigger cell death via the apoptosis pathway under low concentration and low light power irradiation, thereby avoiding dark toxicity. Aza-BODIPY created using this procedure has excellent photothermal efficiency and could serve as a potential candidate for the treatment of cancer cells and tumors.