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Facile strategy enabling the fabrication of carbon dots (CDs) with favorable performance useful for various applications is highly desirable. Here, we report the fabrication of highly fluorescent carbon dots (CDs) towards sensitive metal ion detection, brightly fluorescent printing pattern, as well as green flame retardants for synthetic polymeric materials. CDs are synthesized by solvothermal treatment of polypropylene carbonate (PPC) with ethylenediamine, and the quantum yield of CDs could increase from 30 to 86% by further adding trace of citric acid. The abundant functional groups on the surface of CDs allow CDs well incorporated into polymers to form CD-loaded polystyrene (PS) microspheres, which are employed to construct fluorescent supraballs via triphase microfluidic technique and used as “inks” for uniform fluorescent patterns. Interestingly, the resultant CDs show good flame retardancy for highly flammable polymeric foams and fibers. The CDs surpass previously reported flame-retardant additives, to show excellent combustion resistance that the addition of 20 wt% CDs causes 75% decrease in the peak of heat release rate (P-HRR) for polyurethane (PU) foams. Significantly, a molecular dynamics simulation process for PU/CDs combustion is constructed. This work may spur the preparation and application of high-performance carbon-based nanomaterials.

The cracked morphology and iridescent properties of photonic crystal (PC) films have greatly limited their applications in the field of color pigments and optical instruments. Herein, we fabricated...

We aimed to investigate the hesitancy and willingness of parents to vaccinate themselves and their children with a booster dose against severe acute respiratory syndrome coronavirus 2 and related factors. We conducted a cross-sectional study in Puyang city, China. The information was collected, including demographic characteristics, willingness to receive a booster dose of coronavirus disease 2019 (COVID-19) vaccine, and attitudes and concerns toward COVID-19 and vaccines. Vaccine hesitancy was assessed in individuals completing the first two doses and booster eligible, while vaccine willingness was assessed in those completing the first two doses and not yet booster eligible. Among the participants completing two primary doses while not meeting the booster criteria, 95.4% (1465/1536) and 95.0% (1385/1458) had a willingness to a booster dose of COVID-19 vaccine for themselves and their children, respectively. Among the participants who met the booster criteria, 40.3% had vaccine hesitancy. Vaccine hesitancy and unwillingness tended to occur in people who were younger, less educated, less healthy, and with unsureness of vaccines' efficacy and adverse events (AE). The younger age of children, children in poorer health, and concern about the efficacy and AE of vaccines contributed to the participants' unwillingness to vaccinate their children. We observed a high willingness to the booster dose of COVID-19 vaccine both for the parents and their children, regardless of the eligibility to a booster dose. However, 40% of people had delayed vaccination behaviors. The promotion of scientific knowledge of vaccines' effectiveness and safety is needed, especially for people in poor health and parents with young children. Timely disclosure of AE caused by COVID-19 vaccines and proper aiding offered to people encountering AE are suggested.

Purpose: To evaluate the characteristics and associated risk factors of early postoperative intraocular pressure (IOP) spike in patients undergoing phacoemulsification with intraocular lens implantation and goniosynechialysis in primary angle-closure glaucoma.Design: Retrospective case series.Patients and Methods: Patients with consecutive primary angle-closure glaucoma patients without previous incisional glaucoma surgery who had undergone phacoemulsification with intraocular lens implantation and goniosynechialysis (PEI-GSL) by the same surgeon between January 2017 and November 2019 were reviewed to obtain the demographic information, number of antiglaucoma medications, preoperative IOP, pre-operative peripheral anterior synechiae (P-PAS), axial length (AL), anterior chamber depth (ACD), lens thickness (LT), mean deviation (MD), as well as pattern standard deviation (PSD) of the visual field (VF), Optic Vertica Cup-to-Disc ratio (C/D), intraoperative PAS remain (I-PAS), and postoperative outcomes. A postoperative early IOP spike was defined as an IOP of at least 21 mmHg at 2 h post-operation. The main outcome parameters were the frequency and distribution of postoperative IOP spikes and the risk factors associated with an IOP spike after PEI-GSL.Results: Of 100 eyes (100 patients) included in the study, 32% showed an early IOP spike (IOP spike group), while 68% showed no early IOP spike (no IOP spike group). Eleven patients (34.3%) from the IOP spike group showed an IOP value of ≥30 mmHg, and all underwent 2.82 times of aqueous humor release postoperatively. In the IOP spike group, twelve patients (37.5%) showed an IOP value of ≥21 mmHg at postoperative day (POD) 1, while three (9.4%) showed an IOP value of ≥21 mmHg at POD 7. The overall success rate was 89.74%, and the qualified success rate was 95.12% at the last follow-up (mean = 19.9 months, range 6–46 months). There was no significant difference in the frequency of IOP levels of ≥ 21 mmHg between the IOP spike group and the non-IOP spike group at the last visit (Fisher exact test, P = 1.000). Diagnosis of APACG or CPACG was associated with P-PAS, ACD, and PSD of VF but not with IOP spike (F = 4.003, P = 0.045).Conclusions: A significant percentage of PACG patients undergoing PEI-GSL had IOP spike at 2 h postoperatively. Side-port release of aqueous humor and use of antiglaucoma medications can effectively reduce IOP within one week after surgery. IOP spike was observed more frequently in patients with CPACG than in patients with APACG at 2 h postoperatively. Postoperative IOP spike did not affect the long-term success rate of IOP control.

The growing importance of peptides and proteins in therapeutic and biomedical applications has provided immense motivation toward the development of new ways to construct and transform peptide mole...

In recent years, quantum dots (QDs) have attracted considerable research interests in the fields of biomedicine, energy, optoelectronics, and photocatalysis owing to their unmatched luminescent properties, excellent fluorescence stability, and relatively low cost. Microfluidic technology for the synthesis of QDs has shown unparalleled superiority as a result of its simple operation, fast heat and mass transfer, and precise control of reaction parameters. In this review, we will focus on the application of microfluidic platforms in the synthesis of single core and core-shell semiconductor QDs, perovskite QDs (PQDs) and carbon quantum dots (CQDs). We do expect that this review will provide new insights for the fabrication of various QDs and nanomaterials by microfluidic reaction platforms.

A Minisci-type δ-selective C(sp3)–H heteroarylation of sulfonyl-protected primary aliphatic amines with N-heteroarenes under photoredox-catalyzed conditions was developed. The reaction typically us...

A new strategy is demonstrated to fabricate colorful colloidal photonic crystal fibers (CPCFs) by microfluidic spinning technique. We employed a homogeneous mixture of viscous polyvinylpyrrolidone (PVP) and monodisperse SiO2 particles to fabricate micro-scale fibers. By manipulating the motor speed of the microfluidic spinning machine, various diameter fibers were produced efficiently. Monodisperse SiO2 particles can assemble into photonic crystal structures by removing PVP through calcination and show bright structural colors, which can be easily adjusted by changing the sizes of SiO2 colloids. In addition, we successfully fabricated humidity-sensitive polyacrylamide (PAM)/CPCFs, which exhibited obvious color response to the environmental humidity. The chromatic transitions span over almost the whole visible spectrum. This work might promote the development of colorful colloidal photonic crystal fibers via a microfluidic spinning technique.

We report a highly efficient and chemoselective Minisci-type alkylation reaction of N-heteroarenes with alkanes under the reagent control of a hypervalent iodine oxidant PFBI-OH. In addition to the high reactivity, PFBI-OH demonstrated a high steric sensitivity for H abstraction of alkanes. This reaction is selective for more sterically accessible secondary C–H bonds over weaker tertiary C–H bonds. High selectivity toward penultimate methylene groups was observed for a wide range of acyclic alkanes.

Reversible cleavage of C(sp3)-H bonds can enable racemization or epimerization, offering a valuable tool to edit the stereochemistry of organic compounds. While epimerization reactions operating via cleavage of acidic C(sp3)-H bonds, such as the Cα-H of carbonyl compounds, have been widely used in organic synthesis and enzyme-catalyzed biosynthesis, epimerization of tertiary carbons bearing a nonacidic C(sp3)-H bond is much more challenging with few practical methods available. Herein, we report the first synthetically useful protocol for the epimerization of tertiary carbons via reversible radical cleavage of unactivated C(sp3)-H bonds with hypervalent iodine reagent benziodoxole azide and H2O under mild conditions. These reactions exhibit excellent reactivity and selectivity for unactivated 3° C-H bonds of various cycloalkanes and offer a powerful strategy for editing the stereochemical configurations of carbon scaffolds intractable to conventional methods. Mechanistic study suggests that the unique ability of N3• to serve as a catalytic H atom shuttle is critical to reversibly break and reform 3° C-H bonds with high efficiency and selectivity.

Vehicle lightweighting has been considered as one of the most important solutions to improve fuel economy and reduce harmful emissions. Considering the PowerTrain System (PTS) lightweighting of a heavy-duty truck tractor, cast iron of which the transmission shell was made is replaced with aluminum. Such weight reduction caused the irrationality of the natural frequency matching and the vehicle NVH performance become worse. In order to evaluate the influence of PTS lightweighting on the vibration and noise, the theoretical analysis and experimental tests have been done. The Genetic Algorithm (GA) method was adopted for the Powertrain Mounting System (PMS) optimization. Considering the installation position of PMS, the limitations of package space, cost and available time, the mounting stiffness was chosen as the design variables. One combination of the main vibration energy distribution of PMS was selected as the objective function of optimization design. After optimization, the vehicle experimental study was carried out to investigate the vibration and noise performance of the PMS at idle and Whole Open Throttle (WOT). The test results show that the optimization of PMS had a significant improvement on the vehicle vibration and noise performance.

We report a unified photoredox-catalysis strategy for both hydroxylation and amidation of tertiary and benzylic C-H bonds. Use of hydroxyl perfluorobenziodoxole (PFBl-OH) oxidant is critical for efficient tertiary C-H functionalization, likely due to the enhanced electrophilicity of the benziodoxole radical. Benzylic methylene C-H bonds can be hydroxylated or amidated using unmodified hydroxyl benziodoxole oxidant Bl-OH under similar conditions. An ionic mechanism involving nucleophilic trapping of a carbocation intermediate by H2O or CH3CN cosolvent is presented.

To study the low temperature liquefaction characteristics of SF6 for the operation security of electric equipments in cold area, the writer carries out the low temperature liquefaction test of SF6 respectively in laboratory and outdoors by using SF6 gas low temperature experimental apparatus. According to the results of the test and the Beattie-Bridgman SF6 empirical formula, SF6 gas state parameter curve is plotted and a concise practical SF6 gas state parameter formula is got. This formula is more applicable to electric equipments outdoors. The results show that SF6 gas is easier to liquefy in cold area, and the liquefaction temperature of SF6 gas is in proportion to gas pressure. So the liquefaction temperature of electric equipments operated in cold area should not be higher than the lowest area temperature. Otherwise, measures must be taken to prevent SF6 gas from liquefaction.

A highly tunable radical-mediated reaction system for the functionalization of tertiary aliphatic C–H bonds was developed. Reactions of various substrates with the Zhdankin azidoiodane reagent 1, Ru(bpy)3Cl2, and visible light irradiation at room temperature gave C–H azidated or halogenated products in an easily controllable fashion. These reactions are efficient, selective, and compatible with complex substrates. They provide a potentially valuable tool for selectively labeling tertiary C–H bonds of organic and biomolecules with tags of varied chemical and biophysical properties for comparative functional studies.

C28H27Cl2N3Pd, monoclinic (no. 15), C2/c, a = 24.7394(17) Å, b = 15.9451(11) Å, c = 27.4301(19) Å, β = 107.8650°, V = 10293.7(12) Å3, Z = 16, R gt(F) = 0.0249, wR ref(F 2) = 0.1168, T = 100(2) K.

We aim to perform a series of field measurements for high-speed railway tunnels in China to obtain the micropressure wave (MPW) at the tunnel exit and the transient pressures near the tunnel portals. The relationship between the MPW and the nose-entry wave and the effects of train speed and the tunnel exit hole on the MPW are analyzed. The results show that the MPW decreases with increasing distance from the tunnel exit, but increases rapidly with increasing train speeds. Additionally, holes in the hoods near the tunnel exit could decrease the MPW near the tunnel exit by 10–20%.

A novel metal-free reduction system, in which H

Reversible cleavage of C(sp

C25H31Cl2N3OPd, orthorhombic, Pbca (no. 61), a = 9.4083(4) Å, b = 17.1334(8) Å, c = 31.9251(14) Å, V = 5146.2(4) Å3, Z = 8, R gt(F) = 0.0600, wR ref(F 2) = 0.1232, T = 293(2) K.

Hot water, acting as a mildly acidic catalyst, efficiently promoted intramolecular direct nucleophilic substitution reactions of unsaturated alcohols with heteroatom or carbon nucleophiles. In a mixed solvent of water and 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), polyene cyclizations using allylic alcohols as initiators gave the desired cyclized products, and in neat HFIP, a tricyclization reaction gave a tetracyclic product in 51% chemical yield.

A new protocol for photochemical perfluoroalkylation reactions using perfluoroalkyl iodide, amine additive, and THF solvent is reported. This protocol does not require a photoredox catalyst and proceeds at ambient temperature with irradiation from a compact fluorescent lamp, low-intensity UV lamp, or sunlight. This protocol can be applied to the synthesis of perfluoroalkyl-substituted phenanthridines as well as effect the iodo-perfluoroalkylation of alkenes/alkynes and the C–H perfluoroalkylation of electron-rich arenes and heteroarenes. This C–H perfluoroalkylation reaction offers a unique method for site-selective labeling of oligopeptides at the tryptophan residue.

AMD is the main cause of visual impairment in people over 50 years of age and the most common cause of blindness. In recent years, the use of bevacizumab to treat neovascular AMD has become a preferred treatment in the United States. However, whether bevacozumab is available for RPE or AMD patients is unknown. We firstly indicate that Pam3CSK4 (P3C) activates TLR2 pathway during ARPE-19 apoptosis as determined by western blotting. And then, the expression of MyD88, NF-κB, p-IKK in primary RPE cells from AMD patients is significantly down-regulated after treatment with 50 µg L−1 Bevacizumab. Therefore, our data shows that MyD88 is involved in the TLR2 pathway in ARPE-19 cell apoptosis resulting from Pam3CSK4 (P3C). And more importantly, our findings suggested that Bevacizumab cured age-related macular degeneration (AMD) via down-regulate Toll—like receptor 2 (TLR2) pathway in RPE from AMD patients.

Conservatories at gardens by the bay in Singapore consist of Cool Dry and Cool Moist, which are intended for the display of plants that typically thrive separately in cool dry and cool moist climates. The envelope itself consists of a grid shell-arch steel structure with a double glazed skin that sits directly on the grid shell, and the arches are the main load-bearing components. This paper analyzed the stability of one single arch whose span is the longest one in the corresponding structure, including buckling analyses and non-linear full range analyses. It also carried out stability analyses on some arch segments. The results showed that the stability bearing capacity of single arches met requirements, while some arch segments didn’t. After using the stiffening ribs, the local stability reached its requirements.

The accurate spatial 3D models and corresponding coordinates of every key point are needed to determine the sizes, shapes, and locations of installation for all curtain wall elements in the process of production and construction. To solve the transition problems between architectural design and construction design of curtain wall system, four kinds of single-constrained computer-aided 3D modeling algorithm for spatial point-line models were discussed in detail. Then, a multi-constrained iterative 3D modeling process was proposed by considering coupling relationships amongst the various constraints. A 3D modeling system named T3-CW-CAD was developed and applied to the Shenzhen Airport Terminal 3. The application results showed that the presented-algorithm can meet the overall demand for automatically generating multi-layer 3D models according to spatial point-line model, along with sizes and other restraints amongst curtain wall elements, therefore playing a key role in guiding the production and construction of curtain wall system.

One nonlinear and one linear trinuclear copper(II) complex [Cu3(dien)2(pdc)2CH3OH]2 · 6CH3OH (1) and [Cu3(pdc)2(CH3OH)6(H2O)4] (2) were prepared and characterized structurally, where dien is diethylenetriamine and pdc3− the trianion of 3,5-pyrazoledicarboxylic acid. Both complexes consist of 3,5-pyrazoledicarboxylato-bridged trinuclear copper(II) centers. In 1, copper(II) ions are five-coordinate in distorted square pyramids with bond angles 164.78° for Cu(1)–Cu(2)–Cu(3) and 164.51° for Cu(4)–Cu(5)–Cu(6). In 2, the three copper(II) ions are six-coordinate with elongated octahedral geometry. The trinuclear units of 1 and 2 interact through hydrogen bonds to form 3-D and 2-D supramolecular networks, respectively. Variable temperature magnetic susceptibility measurements show that 1 and 2 are antiferromagnetically coupled with J values of −11.2 and −13.3 cm−1.

Three novel cadmium(II) complexes [Cd 2 (tbpo)(O 2 CC 6 H 4 - p -NO 2 ) 2 ]ClO 4 ·3CH 3 OH ( 1 ) [Cd 2 (bbap)(O 2 CC 6 H 4 - p -NO 2 ) 2 ]ClO 4 ·4.5CH 3 OH·0.75H 2 O ( 2 ) and [Cd(ntb)(O 2 CC 6 H 4 - p -NO 2 )]ClO 4 ·4CH 3 OH ( 3 ) have been synthesized and characterized by IR, elemental analysis, 1 H NMR and X-ray crystallography, where tbpo − and bbap − are anions of N , N , N ′, N ′-tetrakis(2-benzimidazolylmethyl)-2-hydroxo-1,3-diaminopropane and 2,6-bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenol, respectively; ntb is tris(2-benzimidazolymethyl)amine. Complexes 1 and 2 contain μ - phenolate-bridged and μ - alkoxo-bridged dicadmium(II) cores with the Cd1⋯Cd2 separation of 3.671 A for complex 1 and 3.718 A for 2 . One of the 4-nitrobenzoate anions bridged the two cadmium(II) ions in syn-anti mode through its carboxylate group, the other 4-nitrobenzoate is only coordinated with Cd2 in bidentate chelating mode. The two central cadmium(II) atoms are in trigonal bipyramidal and pentagonal bipyramidal geometry. In complex 3 , the cadmium(II) atom is coordinated with four nitrogen atoms of ntb and one carboxylate oxygen atom of 4-nitrobenzoate in distorted trigonal bipyramidal geometry. Experiment shows that there is a higher affinity of 4-nitrobenzoate anion as coligand with the dinuclear [Cd 2 (tbpo)] 3+ and [Cd 2 (bbap)] 3+ cores than that with the mononuclear [Cd(ntb)] 2+ core.

Two novel cadmium(II) complexes, [Cd(ntb)(O 2 CC 6 H 4 - p -Cl)]ClO 4 ·3CH 3 OH ( 1 ) and [Cd 2 (bbap)(O 2 CC 6 H 4 - p -Cl) 2 ]NO 3 ·3C 2 H 5 OH·H 2 O ( 2 ) have been synthesized and structurally characterized by elemental analysis, IR, 1 H NMR and single crystal X-ray diffraction, where ntb is tris(2-benzimidazolymethyl)amine, bbap − is anion of 2,6-bis[bis(2-benzimidazolylmethyl)aminomethyl]-4-methylphenol. In complex 1 , the cadmium ion is coordinated with four nitrogen atoms of ntb and two oxygen atoms of 4-chlorobenzoate anion in bidentate O,O′-chelating mode. In complex 2 , the two cadmium ions are held together by the μ -phenoxo bridge of bbap - with Cd1⋯Cd2 separation of 3.934 A. Each of the two cadmium ions is further coordinated with the carboxylate group of 4-chlorobenzoate in bidentate O,O′-chelating mode. Complexes 1 and 2 are interlinked through hydrogen bonds to form 1D chain structures, the chains are further extended to 2D supramolecular network through hydrogen bonding and π–π stacking interactions. Both complexes present strong fluorescent emission in the solid state at room temperature. Experiment shows that there is a higher coordination ability of the carboxylate group of 4-chlorobenzoate as coligand with the dinuclear [Cd 2 (bbap)] 3+ core than with the mononuclear [Cd(ntb)] 2+ core.

The low-molecular-weight and easily prepared N-thiobenzoyl 1-methyl-histidine methyl ester 3k was utilized to efficiently catalyze the kinetic resolution of racemic secondary alcohols. Comparison of the conformations of amide catalyst 3c and thioamide catalyst 3k was made to understand the origin of the improvement of the enantioselectivity by thioamide modification.

A broad spectrum of alcohol substrates is successfully used in the title reactions to produce furan- or pyran-containing structures in etherification processes as well as tri- and tetracyclic ring systems in polyene cyclization.

Backgound: Chitosan/polyvinyl alcohol corneal cap has good biocompatibility and drug slow release characteristics, which provided new treatment method for anterior segment disease. Our study was to evaluate biocompatibility of poly (vinyl alcohol)/chitosan corneal shield’s intraocular and investigate its feasibility to treat ocular surface disorders. Methods: Thirty-six white rabbits were randomly divided into four groups. Slit lamp observation were conducted at 1, 3, 7 and 10 days after operation. Corneal and conjunctiva tissue harvested from the experimental groups was observed by HE staining 10 days after operation. The aqueous humor was aspirated from the anterior chamber at each designated time point (1, 3, 7 and 10 days). The cornea and conjunctive were collected at 10 days. The concentration of each tissue was analyzed by ultra-performance liquid chromatography and microscope observation. Results: In all groups, mild hyperemia was observed 1 day after operation, and there was no obvious inflammatory reaction occurring on the seventh and tenth day. No corneal edema and inflammatory reaction of anterior chamber occurred till the tenth day. For histopathology, there was no obviously mild chronic and inflammatory reaction occurred, and no significant difference between the corneal shield with-in groups and with-out groups. The drug concentrations in corneal and conjunctival in group (A, B) were significantly lower than eye drops in the control group (C, D), and blank corneal cover in group C was significantly sham operation in group D. Conclusion: The results indicated that the proposed membrane combined with ophthalmic solution has substantial potential as ocular delivery system.

C34H39Cl2N3O2Pd, triclinic, P1̅, a = 10.3988(8) Å, b = 12.1983(10) Å, c = 12.9114(10) Å, α = 85.034(1)°, β = 89.123(1)°, γ = 79.519(1)°, V = 1604.4(2) Å3, Z = 2, R gt(F) = 0.0472, wR ref(F 2) = 0.1285, T = 100(2) K.

C18H25Br2N3Pd, orthorhombic, P212121 (no. 19), a = 9.8678(4) Å, b = 13.8740(6) Å, c = 14.7557(6) Å, V = 2020.14(15) Å3, Z = 4, R gt (F) = 0.0182, wR ref (F 2 ) = 0.0443, T = 173(2) K.

To evaluate the adverse effects of particulate matter ≤ 2.5 µm in aerodynamic diameter (PM2.5) on public health in four typical cities: Beijing, Shanghai, Guangzhou and Xi'an.Daily health and meteorological data (including ambient temperature and relative humidity) were collected in the past several years. For the relative risk of PM2.5 effects on mortalities, generalized additive model (GAM) was used to obtain the exposure-response coefficients between PM2.5 and non-accidental mortalities after controlling time trend, week effects and meteorological factors. Then excess mortalities were calculated according to coefficients, health data and air pollution level.The relative risks of PM2.5 effects on mortalities were 1.0027(1.0010-1.0044), 1.0020 (1.0007-1.0033) , 1.0056 (1.0022-1.0091), 1.0036 (1.0011-1.0061) for Beijing, Xi'an, Shanghai, Guangzhou respectively. Compared with relative risks in northern cities (Beijing and Xi'an), relative risks in southern cities (Shanghai and Guangzhou) were higher. The numbers of excess mortalities caused by PM2.5 in Beijing, Shanghai, Guangzhou, Xi'an were 2349, 2980, 1715, 726 and accounted for 1.9%, 1.6%, 2.2% and 1.6% of the total death number in 2010 respectively.Although relative health risks caused by PM2.5 vary geographically for urban residents, public health is endangered. More efforts should be devoted to reducing PM2.5 pollution.