Synthesis of zinc porphyrins and effect of peripheral substituents on the coordination reaction

Three free-base porphyrins, modified with Boc-d-threonine and their zinc porphyrins have been synthesized using benzaldehyde, 4-chlorobenzaldehyde, and 4-methoxybenzaldehyde. The effects of peripheral substituents on the coordination reactions between zinc porphyrins and imidazole derivatives have been studied by UV-visible spectroscopy, fluorescence spectrometry, and theoretical calculations. The results show that the coordination reaction forms a Zn-N bond between zinc porphyrins involving different peripheral substituents and imidazole derivatives. The association coordination constants decrease (N-MeIm > Im) due to the change in enthalpy; the zinc porphyrin synthesized using 4-chlorobenzaldehyde and N-methylimidazole shows the largest association constant. Fluorescent quenching is observed during the coordination process with the zinc porphyrin synthesized using 4-methoxybenzaldehyde and N-methylimidazole showing the largest Stern-Volmer quenching rate constant. In addition, theoretical calculations have been used to investigate essential characteristics of the reaction, charges, bond lengths, and bond energies for each system

Electrical properties of yttrium calcium oxyborate crystal annealed at high temperature and low oxygen partial pressure

The yttrium calcium oxyborate crystal (YCa 4 O(BO 3 ) 3 , YCOB) has been actively studied for high-temperature piezoelectric sensing applications. In this work, the stability of electric properties of YCOB crystal annealed in critical conditions (high-temperatures of 900-1100 °C with a low oxygen partial pressure of 4 x 10 −6 atm for 24 h) was investigated and the recovery mechanism for the electrical resisitivity, dielectric permittivity and dielectric loss were studied, taking advantage of the X-ray photoelectron spectra and the first principle calculations. The electrical resistivity of the annealed YCOB crystal was slightly decreased when compared to the pristine counterpart, being (2-5) x 10 7 Ω cm at 850 °C. The dielectric permittivity and dielectric loss were found to increase after annealing, showing recoverable behaviours after thermal treatment above 650 °C in air. The calculated vacancy formation energy indicate that the oxygen vacancy is the dominant defects in YCOB. The formation of oxygen vacancy weakens the chemical bonding strength between B (Ca or Y) and O atoms, introduces extra donor levels in the band gap, which excites the electrons to conduction band more easily thus enhances the electrical conductivity and dielectric loss. The recovered electrical properties are believed to be associated with the reduced vacancy defects at elevated temperatures in air

Case report: A rare case of sintilimab-induced gastric stenosis and literature review

Sintilimab is a fully human IgG4 monoclonal antibody against programmed death-1 (PD-1) used to treat classical Hodgkin’s lymphoma and various solid tumors. With increasing use of sintilimab, some rare adverse reactions have been reported. Here, we report a case of a 50-year-old woman with squamous non-small cell lung cancer (NSCLC) (metastasis to pericardium and pleura) who received two cycles of 200 mg sintilimab immunotherapy combined with albumin-bound paclitaxel and carboplatin chemotherapy and one cycle of sintilimab monotherapy. She was diagnosed with Sjogren’s syndrome (with symptoms of fever, dry mouth, dysphagia, and eating difficulty) after three cycles’ treatment and received standard steroidal therapy. Prior to admission, the patient experienced severe stomach discomfort with vomiting and was hospitalized. Upper gastrointestinal iodine angiography showed significant gastric stenosis as well as lower esophageal stenosis. Subsequent ultrafine gastroscopy revealed ulceration at the stenotic site and an absence of normal peristalsis of the gastric wall. Pathological examination of the lesions showed reactive changes, including ulceration, fibrosis, and inflammatory cell infiltration. After multidisciplinary consultation, it was considered that the patient’s gastric stenosis with inflammatory fibrosis changes was due to a sintilimab-induced immune hyperinflammatory reaction. The patient had been treated with standard steroidal therapy since suffering from Sjogren’s syndrome, but the gastric stenotic changes were not relieved. The patient then received regular bouginage of esophago-cardiac stenosis under gastroscopy to physically reexpand the fibrous hyperplasia and stenotic site, enabling normal eating function. To our knowledge, this is the first case of gastric stenosis in a patient with squamous NSCLC after using sintilimab and may help clinicians better understand potential immune-related adverse events due to sintilimab and improve assessment and management

Deep Brain Stimulation Complications in Patients With Parkinson’s Disease and Surgical Modifications: A Single-Center Retrospective Analysis

BackgroundAs a complication-prone operation, deep brain stimulation (DBS) has become the first-line surgical approach for patients with advanced Parkinson’s disease (PD). This study aimed to evaluate the incidence and risk factors of DBS-associated complications.MethodsWe have reviewed a consecutive series of patients with PD undergoing DBS procedures to describe the type, severity, management, and outcome of postoperative complications from January 2011 to December 2018. Both univariate and multivariate analyses were performed to identify statistically significant risk factors. We also described our surgical strategies to minimize the adverse events.ResultsA total of 225 patients underwent 229 DBS implantation procedures (440 electrodes), of whom 20 patients experienced 23 DBS-associated complications, including ten operation-related complications and 13 hardware-related ones. Univariate analysis elucidated that comorbid medical conditions (P = 0.024), hypertension (P = 0.003), early-stage operation (P < 0.001), and unilateral electrode implantation (P = 0.029) as risk factors for overall complications, or more specifically, operation-related complications demonstrated in the stratified analysis. In contrast, no risk factor for hardware-related complications was identified. Statistical significances of hypertension (OR = 3.33, 95% CI: 1.14–9.71, P = 0.027) and early-stage (OR = 11.04, 95% CI: 2.42–50.45, P = 0.002) were further validated via multivariate analysis. As the annual number of DBS procedures increased, the incidence of complications gradually decreased (R = −0.699, P < 0.01). Additionally, there was a strong correlation between surgical complications and unplanned readmission (R = 0.730, P < 0.01).ConclusionThe importance of cumulative experience and relevant technique modifications should be addressed to prevent DBS-associated complications and unplanned readmission

Real-time Monitoring for the Next Core-Collapse Supernova in JUNO

Core-collapse supernova (CCSN) is one of the most energetic astrophysical events in the Universe. The early and prompt detection of neutrinos before (pre-SN) and during the SN burst is a unique opportunity to realize the multi-messenger observation of the CCSN events. In this work, we describe the monitoring concept and present the sensitivity of the system to the pre-SN and SN neutrinos at the Jiangmen Underground Neutrino Observatory (JUNO), which is a 20 kton liquid scintillator detector under construction in South China. The real-time monitoring system is designed with both the prompt monitors on the electronic board and online monitors at the data acquisition stage, in order to ensure both the alert speed and alert coverage of progenitor stars. By assuming a false alert rate of 1 per year, this monitoring system can be sensitive to the pre-SN neutrinos up to the distance of about 1.6 (0.9) kpc and SN neutrinos up to about 370 (360) kpc for a progenitor mass of 30$M_{\odot}$ for the case of normal (inverted) mass ordering. The pointing ability of the CCSN is evaluated by using the accumulated event anisotropy of the inverse beta decay interactions from pre-SN or SN neutrinos, which, along with the early alert, can play important roles for the followup multi-messenger observations of the next Galactic or nearby extragalactic CCSN.Comment: 24 pages, 9 figure

Hydrodynamics and mass transfer in an internal airlift slurry reactor for process intensification

By combining the prominent advantage of directional fluid flow in an internal airlift loop reactor with the cheap cost of liquid-solid separation in a hydrocyclone, a new slurry reactor for process intensification integrating solid catalytic reactions with liquid-solid separation for clear liquid products is proposed and designed to cut down the capital and operating costs. The reactor can be operated properly when the superficial gas velocity is above 0.0108 m/s, and the solid particles of aluminum oxide are all retained in the slurry reactor if the particle diameter is larger than 57.9 mu m. The influences of superficial gas velocity and top clearance on the performance of hydrodynamics and mass transfer in the gas-liquid two-phase and the gas-liquid-solid three-phase systems are measured and discussed systematically, and some data base for the rational design, optimization and scaling-up of this type of promising reactor is provided. (C) 2018 Elsevier Ltd. All rights reserved.</p

Study on Top Hierarchy Control Strategy of AEBS over Regenerative Brake and Hydraulic Brake for Hub Motor Drive BEVs

A hub motor is an effective drive system for Battery Electric Vehicles (BEVs). However, due to limitations on packaging and cost, there are few applications in which hub motors are taken as the only actuators for a brake vehicle. Most applications involve a Regenerative Braking System (RBS) combined with a Hydraulic Braking System (HBS). In this paper, a top hierarchy Advanced Emergency Braking System (AEBS) controller is designed in Matlab/Simulink and State-flow, including functionalities of basic emergency braking, brake force distribution between front and rear wheels, anti-lock braking and coordination between RBS and HBS based on Model Predictive Control (MPC); a Seven Degrees of Freedom (DOF) BEV chassis model is constructed and rear-end crash test scenarios are created in Carsim with a high and low road adhesion coefficient. A series of comparison tests show that not only are the stopping distances between the ego vehicle and target vehicle shorter, but also the braking torques, longitudinal slip ratio and rotation speed of each wheel are well controlled without wheel locking. To sum up, in addition to meeting the AEBS requirements of avoiding a rear-end collision, the control strategy developed in this paper also levels up braking performance and enhances vehicle stability on both high-mu and low-mu roads for BEVs driven by a hub motor independently

In-situ micro-impacting assisted directed energy deposition-arc of aluminum alloy: Formability and microstructure

At present, the in-situ forging devices do not have the ability to flexibly adjust impacting forces over a wide frequency range and cannot be easily integrated, which restricts its application on DED-arc (directed energy deposition-arc) technology for additive manufacturing. A novel method and system of in-situ micro-impacting assisted DED-arc based on a compact high-dynamic linear actuator was proposed, developed and verified in arc deposition of 5B06 aluminum alloy. The terminal impacting head could be sufficiently close to the molten pool to enforce the obtaining of flat surface of the deposited layer. The results show that the in-situ micro-impacting could produce accumulating rapid micro-deformation and thus induce a gradient microstructure. DDRX (discontinuous dynamic recrystallization) and CDRX (continuous dynamic recrystallization) hybrid dynamic recrystallization behavior was observed. The microhardness of impacted samples was increased by 9.5 % and 8.0 % in vertical and horizontal direction, respectively. The process of rapid micro-deformation contributes to the retaining of the in-situ work-hardening effect at high temperatures, which made the proposed in-situ impacting method a preferred option for DED-arc additive manufacturing

Graphitic carbon nitride with thermally-induced nitrogen defects: an efficient process to enhance photocatalytic H2production performance

Graphitic carbon nitride (g-C3N4, CN) with nitrogen vacancies was synthesized by a controlled thermal etching method in a semi-closed air-conditioning system. The defect-modified g-C3N4shows an excellent photocatalytic performance demonstrated by water splitting under visible light irradiation. With proper heat-treatment durations such as 2 h (CN2) and 4 h (CN4) at 550 °C, the hydrogen production rates significantly increase to 100 µmol h-1and 72 µmol h-1, which are 11 times and 8 times the rate of the pristine CN (8.8 µmol h-1) respectively. The excellent hydrogen production performance of nitrogen defect modified CN2 is due to the synergy effect of the decreased band gap, enlarged specific surface area and increased separation/migration efficiency of photoinduced charge carriers. This simple defect engineering method provides a good paradigm to improve the photocatalytic performance by tailoring the electronic and physical structures of g-C3N4