Publications by authors named "Jianyu Zhang"

110 Publications

First Measurement of Polarizations in the Decay D^{0}→ωφ.

Phys Rev Lett 2022 Jan;128(1):011803

Turkish Accelerator Center Particle Factory Group, Istanbul Bilgi University, 34060 Eyup, Istanbul, Turkey.

Using a data sample corresponding to an integrated luminosity of 2.93  fb^{-1} collected at a center-of-mass energy sqrt[s]=3.773  GeV by the BESIII detector, the decay D^{0}→ωϕ is observed for the first time. The branching fraction is measured to be (6.48±0.96±0.40)×10^{-4} with a significance of 6.3σ, where the first and second uncertainties are statistical and systematic, respectively. An angular analysis reveals that the ϕ and ω mesons from the D^{0}→ωϕ decay are transversely polarized. The 95% confidence level upper limit on longitudinal polarization fraction is set to be less than 0.24, which is inconsistent with current theoretical expectations and challenges our understanding of the underlying dynamics in charm meson decays.
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http://dx.doi.org/10.1103/PhysRevLett.128.011803DOI Listing
January 2022

Organic Long-Persistent Luminescence from a Single-Component Aggregate.

J Am Chem Soc 2022 Jan 20. Epub 2022 Jan 20.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong, China.

Long-persistent luminescence (LPL), also known as afterglow, is a phenomenon in which the material shows long-lasting luminescence after the cessation of the excitation source. The research of LPL continues to attract much interest due to its fundamental nature and its potential in the development of the next generation of functional materials. However, most of the current LPL materials are multicomponent inorganic systems obtained after harsh synthetic procedures and often use rare-earth metals. Recently, metal free organic long-persistent luminescence (OLPL) has gained much interest because it can bypass many of the disadvantages of inorganic systems. To date, the most successful method to generate OLPL systems is to access charge-separated states through binary donor-acceptor exciplex systems. However, it has been reported that the ratios of the binary systems affect OLPL properties, complicating the reproducibility and large-scale production of OLPL materials. Simpler OLPL systems can overcome these issues for the benefit of the development and adoption of OLPL systems. Here, we report on the rational design and synthesis of a single-component OLPL system with detectable afterglow for at least 12 min under ambient conditions. This work exemplifies an easy design principle for new OLPL materials. The investigation of the material provides valuable insights toward the generation of OLPL from a single-component system.
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http://dx.doi.org/10.1021/jacs.1c11480DOI Listing
January 2022

Novel Quinolizine AIE System: Visualization of Molecular Motion and Elaborate Tailoring for Biological Application.

Angew Chem Int Ed Engl 2022 Jan 12:e202117709. Epub 2022 Jan 12.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Molecular motions are ubiquitous in nature and they immutably play intrinsic roles in all actions. However, exploring appropriate models to decipher molecular motions is an extremely important but very challenging task for researchers. Considering aggregation-induced emission (AIE) luminogens possess their unique merits to visualize molecular motions, it is particularly fascinating to construct new AIE systems as models to study molecular motion. Herein, a novel quinolizine (QLZ) AIE system was constructed based on the restriction intramolecular vibration (RIV) mechanism. It was demonstrated that QLZ could act as an ideal model to visualize single-molecule motion and macroscopic molecular motion via fluorescence change. Additionally, further elaborate tailoring of this impressive core achieved highly efficient reactive oxygen species production and realized fluorescence imaging-guided photodynamic therapy applications, which confirms the great application potential of this new AIE-active QLZ core. Therefore, this work not only provides an ideal model to visualize molecular motion but also opens a new way for the application of AIEgens.
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http://dx.doi.org/10.1002/anie.202117709DOI Listing
January 2022

Optimization Research of Machining Parameters for Cutting GH4169 Based on Tool Vibration and Surface Roughness under High-Pressure Cooling.

Materials (Basel) 2021 Dec 18;14(24). Epub 2021 Dec 18.

Key Laboratory of Advanced Manufacturing and Intelligent Technology, Ministry of Education, Harbin University of Science and Technology, Harbin 150080, China.

The nickel-based superalloy is widely used in aerospace. It is a typical difficult-to-cut material with poor plasticity. During the cutting process, the fluctuation of the cutting force caused by the change of cutting conditions can aggravate tool vibration, thereby reducing the surface quality of the machined workpiece. However, the emergence of high-pressure cooling technology provides technical support for overcoming the difficulty in superalloy processing. Therefore, it is of great significance to optimize the tool vibration and surface roughness of cutting GH4169 under high-pressure cooling. Taking GH4169 as the research object, the single-factor and orthogonal high-pressure cooling cutting experiments were conducted firstly in this paper. Then, the methods of the main effect diagram and response surface were applied to analyze the impact of cutting speed, feed rate, cutting depth, and cooling pressure on the three-way tool vibration. Next, MATLAB was adopted to draw the frequency spectrum of radial tool vibration at different cutting speeds, and the relationship between chip morphology, tool vibration, and workpiece surface roughness at different cutting speeds was discussed. Based on this, a mathematical model of radial tool cutting vibration and surface roughness related to the cutting amount and cooling pressure was established. Support vector machine (SVM) was applied to make predictions. Meanwhile, the non-dominated sorting genetic algorithm with an elitist strategy was adopted for multi-objective optimization, and the optimization results were verified through experiments. The results indicated that the feed rate and cutting depth had a great impact on the tool vibration and surface roughness. The established mathematical model was accurate and effective for optimizing the cutting parameters. These results are of great significance to improve the cutting stability and the quality of machined surface.
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http://dx.doi.org/10.3390/ma14247861DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8707233PMC
December 2021

Anti-inflammatory sesquiterpenoids from the heartwood of Juniperus formosana Hayata.

Fitoterapia 2021 Dec 21;157:105105. Epub 2021 Dec 21.

School of Pharmaceutical Sciences and the Key Laboratory for Chemical Biology of Fujian Province, Xiamen University, South Xiang-An Road, Xiamen 361102, China. Electronic address:

Juniperus formosana Hayata (J. formosana) is a commom needlebush cultivar growing in China. Six new compounds (1-6), including four cadinene sesquiterpenoids (1-4), one abietane diterpenoid (5), and one β-naphthol derivative (6), along with 18 known compounds (7-24) were isolated and identified through phytochemical investigation on the heartwood of J. formosana. The structures of these compounds were fully elucidated by their 1D and 2D NMR, HR-ESI-MS, UV, and IR spectral data analyses. The absolute configurations of compounds 1, 3, and 5 were confirmed by experimental and calculated electronic circular dichroism (ECD) data. Moreover, X-ray crystallographic analysis was carried out to characterize the structure of compound 4. The inhibitory effects on the nitric oxide (NO) production of all the isolated compounds were initially examined in RAW264.7 macrophages induced by lipopolysaccharide (LPS). The results showed that compounds 3 and 12 possessed significant inhibitory potency on NO generation with IC values of 3.41 μM and 6.15 μM among the new and known compounds, respectively. The expressions of IL-1β, IL-6, and TNF-α were measured in LPS-stimulated RAW264.7 cells to evaluate the anti-inflammatory effects of compounds 1-24. Compounds 1-6 and 9-12 exhibited potent anti-inflammatory effects. Additionally, the expressions of p38, Erk, and IκBα proteins were further determined to explore the anti-inflammatory mechanism of the most potent compounds 3 and 12. Overall, our findings indicate the potential of J. formosana for developing medicine candidates as the treatments of inflammation.
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http://dx.doi.org/10.1016/j.fitote.2021.105105DOI Listing
December 2021

Long decay length of magnon-polarons in BiFeO/LaSrMnO heterostructures.

Nat Commun 2021 Dec 14;12(1):7258. Epub 2021 Dec 14.

Fert Beijing Institute, MIIT Key Laboratory of Spintronics, School of Integrated Circuit Science and Engineering, Beihang University, Beijing, China.

Magnons can transfer information in metals and insulators without Joule heating, and therefore are promising for low-power computation. The on-chip magnonics however suffers from high losses due to limited magnon decay length. In metallic thin films, it is typically on the tens of micrometre length scale. Here, we demonstrate an ultra-long magnon decay length of up to one millimetre in multiferroic/ferromagnetic BiFeO(BFO)/LaSrMnO(LSMO) heterostructures at room temperature. This decay length is attributed to a magnon-phonon hybridization and is more than two orders of magnitude longer than that of bare metallic LSMO. The long-distance modes have high group velocities of 2.5 km s as detected by time-resolved Brillouin light scattering. Numerical simulations suggest that magnetoelastic coupling via the BFO/LSMO interface hybridizes phonons in BFO with magnons in LSMO to form magnon-polarons. Our results provide a solution to the long-standing issue on magnon decay lengths in metallic magnets and advance the bourgeoning field of hybrid magnonics.
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http://dx.doi.org/10.1038/s41467-021-27405-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8671416PMC
December 2021

A CMOS PSR Enhancer with 87.3 mV PVT-Insensitive Dropout Voltage for Sensor Circuits.

Sensors (Basel) 2021 Nov 25;21(23). Epub 2021 Nov 25.

School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798, Singapore.

A new power supply rejection (PSR) based enhancer with small and stable dropout voltage is presented in this work. It is implemented using TSMC-40 nm process technology and powered by 1.2 V supply voltage. A number of circuit techniques are proposed in this work. These include the temperature compensation for Level-Shifted Flipped Voltage Follower (LSFVF) and the Complementary-To-Absolute Temperature (CTAT) current reference. The typical output voltage and dropout voltage of the enhancer is 1.1127 V and 87.3 mV, respectively. The Monte-Carlo simulation of this output voltage yields a mean of 29.4 ppm/°C from -20 °C and 80 °C. Besides, the dropout voltage has been verified with good immunity against Process, Temperature and Process (PVT) variation through the worst-case simulation. Consuming only 4.75 μA, the circuit can drive load up to 500 μA to yield additional PSR improvement of 36 dB and 20 dB of PSR at 1 Hz and 1 MHz, respectively for the sensor circuit of interest. This is demonstrated through the application of an enhancer on the instrumentation Differential Difference Amplifier (DDA) for sensing floating bridge sensor signal. The comparative Monte-Carlo simulation results on a respective DDA circuit have revealed that the process sensitivity of output voltage of this work has achieved 14 times reduction in transient metrics with respect to that of the conventional counterpart over the operation temperature range in typical operation condition. Due to simplicity without voltage reference and operational amplifier(s), low power and small consumption of supply voltage headroom, the proposed work is very useful for supply noise sensitive analog or sensor circuit applications.
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http://dx.doi.org/10.3390/s21237856DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8659595PMC
November 2021

Crystal structure of oligoribonuclease from Vibrio cholerae O1 El Tor with bound peptide.

Acta Crystallogr F Struct Biol Commun 2021 Dec 11;77(Pt 12):437-443. Epub 2021 Nov 11.

State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science and College of Life Sciences, Nankai University, 38 Tongyan Road, Tianjin 300350, People's Republic of China.

Oligoribonuclease (Orn), a member of the DEDDh superfamily, can hydrolyse 2-5 nt nanoRNAs to mononucleotides. It is involved in maintaining the intracellular levels of RNA, c-di-GMP signalling and transcription initiation in many bacterial species. Here, the crystal structure of Orn from Vibrio cholerae O1 El Tor (VcOrn) is reported at a resolution of 1.7 Å. VcOrn, which consists of nine α-helices and six β-strands, crystallizes with a single monomer in the asymmetric unit but forms a homodimer via crystallographic twofold symmetry. Electron density is observed in the active pocket that corresponds to an intersubunit N-terminal expression tag with sequence GPLGSHHH. The positively charged N-terminal tag binds in the negatively charged nucleotide-binding pocket with a buried surface area of ∼500 Å. The N-terminal tag interacts with VcOrn via π-π stacking with two conserved residues involved in nucleotide binding, as well as via salt bridges and hydrogen bonds. The structure reported here reveals that the active pocket can accommodate polypeptides in addition to nucleotides, thus providing an important starting point for investigation into substrate modification and inhibitor design targeting VcOrn.
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http://dx.doi.org/10.1107/S2053230X21011043DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8647215PMC
December 2021

Metal-Based Aggregation-Induced Emission Theranostic Systems.

ChemMedChem 2021 Nov 27:e202100578. Epub 2021 Nov 27.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Guangdong-Hong Kong-Macau Joint Laboratory of Optoelectronic and Magnetic Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Efficient theranostic systems can realize better outcomes in disease treatment because of precise diagnosis and the concomitant effective therapy. Aggregation-induced emission luminogens (AIEgens) are a unique type of organic emitters with intriguing photophysical properties in the aggregate state. Among the AIEgens studied for biomedical applications, so far, metal-based AIE systems have shown great potential in theranostics due to the enhanced multimodal bioimaging ability and therapeutic effect. This research field has been growing rapidly, and many rationally designed systems with promising activities to cancer and other diseases have been reported recently. In this review, we summarized the recent progress of metal-based AIE materials in bioimaging and biological theranostics, and deciphered the pertinent design strategies. We hope that this review can offer new insights into the development of this growing field.
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http://dx.doi.org/10.1002/cmdc.202100578DOI Listing
November 2021

Measurement of the Absolute Branching Fraction of D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}.

Phys Rev Lett 2021 Oct;127(17):171801

Turkish Accelerator Center Particle Factory Group, Istanbul Bilgi University, 34060 Eyup, Istanbul, Turkey.

Using a dataset of 6.32  fb^{-1} of e^{+}e^{-} annihilation data collected with the BESIII detector at center-of-mass energies between 4178 and 4226 MeV, we have measured the absolute branching fraction of the leptonic decay D_{s}^{+}→τ^{+}ν_{τ} via τ^{+}→e^{+}ν_{e}ν[over ¯]_{τ}, and find B_{D_{s}^{+}→τ^{+}ν_{τ}}=(5.27±0.10±0.12)×10^{-2}, where the first uncertainty is statistical and the second is systematic. The precision is improved by a factor of 2 compared to the previous best measurement. Combining with f_{D_{s}^{+}} from lattice quantum chromodynamics calculations or the |V_{cs}| from the CKMfitter group, we extract |V_{cs}|=0.978±0.009±0.012 and f_{D_{s}^{+}}=(251.1±2.4±3.0)  MeV, respectively. Combining our result with the world averages of B_{D_{s}^{+}→τ^{+}ν_{τ}} and B_{D_{s}^{+}→μ^{+}ν_{μ}}, we obtain the ratio of the branching fractions B_{D_{s}^{+}→τ^{+}ν_{τ}}/B_{D_{s}^{+}→μ^{+}ν_{μ}}=9.72±0.37, which is consistent with the standard model prediction of lepton flavor universality.
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http://dx.doi.org/10.1103/PhysRevLett.127.171801DOI Listing
October 2021

Mapping the Regioisomeric Space and Visible Color Range of Purely Organic Dual Emitters with Ultralong Phosphorescence Components: From Violet to Red Towards Pure White Light.

Angew Chem Int Ed Engl 2022 Jan 7;61(4):e202111805. Epub 2021 Dec 7.

Faculty of Chemistry (Organic Chemistry) and Center for NanoIntegration (CENIDE), University of Duisburg-Essen, Universitätsstrasse 7, 45117, Essen, Germany.

We mapped the entire visible range of the electromagnetic spectrum and achieved white light emission (CIE: 0.31, 0.34) by combining the intrinsic ns-fluorescence with ultralong ms-phosphorescence from purely organic dual emitters. We realized small molecular materials showing high photoluminescence quantum yields (Φ ) in the solid state at room temperature, achieved by active exploration of the regioisomeric substitution space. Chromophore stacking-supported stabilization of triplet excitons with assistance from enhanced intersystem crossing channels in the crystalline state played the primary role for the ultra-long phosphorescence. This strategy covers the entire visible spectrum, based on organic phosphorescent emitters with versatile regioisomeric substitution patterns, and provides a single molecular source of white light with long lifetime (up to 163.5 ms) for the phosphorescent component, and high overall photoluminescence quantum yields (up to Φ =20 %).
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http://dx.doi.org/10.1002/anie.202111805DOI Listing
January 2022

A Facile Strategy of Boosting Photothermal Conversion Efficiency through State Transformation for Cancer Therapy.

Adv Mater 2021 Dec 14;33(51):e2105999. Epub 2021 Oct 14.

Shenzhen Institute of Aggregate Science and Technology, School of Science and Engineering, The Chinese University of Hong Kong, Shenzhen, Guangdong, 518172, China.

Improving photothermal conversion efficiency (PCE) is critical to facilitate therapeutic performance during photothermal therapy (PTT). However, current strategies of prompting PCE always involve complex synthesis or modification of photothermal agents, thereby significantly inhibiting the practical applications and fundamental understanding of photothermal conversion. A facile strategy is herein present for boosting PCE by transforming photothermal agents from aggregated state to dispersed state. Compared to aggregated state, the developed photothermal agents with semiconducting nature can rotate freely in dispersed state, which allows for an efficient nonradiative dissipation through twisted intramolecular charge transfer (TICT) effect, consequentially offering excellent photothermal performance. Noteworthy, the state transformation can be achieved by virtue of releasing photothermal molecules from nanoparticles on the basis of a pH-responsive polymer nanocarrier, and the PCE is elevated from 43% to 60% upon changing the pH values from 7.4 to 5.0. Moreover, the nanoparticle disassembly and state transformation behaviors can also smoothly proceed in lysosome of cancer cells, demonstrating a distinct photothermal therapeutic performance for cancer ablation. It is hoped that this strategy of transforming state to boost PCE would be a new platform for practical applications of PTT technique.
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http://dx.doi.org/10.1002/adma.202105999DOI Listing
December 2021

Donor/π-Bridge Manipulation for Constructing a Stable NIR-II Aggregation-Induced Emission Luminogen with Balanced Phototheranostic Performance*.

Angew Chem Int Ed Engl 2021 12 16;60(51):26769-26776. Epub 2021 Nov 16.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research, Center for Tissue Restoration and Reconstruction, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, 999077, China.

Owing to their versatile functionality and tunable energy dissipation, aggregation-induced emission luminogens (AIEgens) have emerged as a potential platform for multimodal theranostics. Nevertheless, the construction of AIE-active phototheranostic agents in the second near-infrared window (NIR-II, 1000-1700 nm), which allows superior resolution and minimized photodamage, is still a formidable challenge. Herein, benzo[c]thiophene serves as an electron-rich and bulky donor (D)/π-bridge, which can enlarge the conjugation length and distort the backbone of an AIEgen. By precise D/π-bridge engineering, highly stable NIR-II AIEgen DPBTA-DPTQ nanoparticles are obtained with acceptable NIR-II fluorescence quantum yield and excellent photothermal conversion efficiency. In addition, the spatial conformation of DPBTA-DPTQ is determined for the first time by X-ray single crystal diffraction and theoretical simulations. DPBTA-DPTQ NPs have good biocompatibility and show efficient photothermal therapeutic effects in in vitro tests. Furthermore, DPBTA-DPTQ NPs were used in fluorescence-photoacoustic-photothermal trimodal imaging-guided photothermal eradication of tumors in HepG2 and B16-F10 tumor-xenografted mice.
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http://dx.doi.org/10.1002/anie.202111767DOI Listing
December 2021

Observation of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e}.

Phys Rev Lett 2021 Sep;127(13):131801

Turkish Accelerator Center Particle Factory Group, Istanbul Bilgi University, 34060 Eyup, Istanbul, Turkey.

Using 2.93  fb^{-1} of e^{+}e^{-} collision data taken with the BESIII detector at a center-of-mass energy of 3.773 GeV, the observation of the D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} semileptonic decay is presented. The statistical significance of the decay D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is greater than 10σ. The branching fraction of D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is measured to be (1.09±0.13_{-0.16}^{+0.09}±0.12)×10^{-3}. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of K_{1}(1270)^{-}→K^{-}π^{+}π^{-}. The fraction of longitudinal polarization in D^{0}→K_{1}(1270)^{-}e^{+}ν_{e} is determined for the first time to be 0.50±0.19_{stat}±0.08_{syst}.
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http://dx.doi.org/10.1103/PhysRevLett.127.131801DOI Listing
September 2021

Similarities and Differences Between HFmrEF and HFpEF.

Front Cardiovasc Med 2021 20;8:678614. Epub 2021 Sep 20.

State Key Laboratory of Organ Failure Research, Department of Cardiology, Nanfang Hospital, Southern Medical University, Guangzhou, China.

The new guidelines classify heart failure (HF) into three subgroups based on the ejection fraction (EF): HF with reduced EF (HFrEF), HF with mid-range EF (HFmrEF), and HF with preserved EF (HFpEF). The new guidelines regarding the declaration of HFmrEF as a unique phenotype have achieved the goal of stimulating research on the basic characteristics, pathophysiology, and treatment of HF patients with a left ventricular EF of 40-49%. Patients with HFmrEF have more often been described as an intermediate population between HFrEF and HFpEF patients; however, with regard to etiology and clinical indicators, they are more similar to the HFrEF population. Concerning clinical prognosis, they are closer to HFpEF because both populations have a good prognosis and quality of life. Meanwhile, growing evidence indicates that HFmrEF and HFpEF show heterogeneity in presentation and pathophysiology, and the emergence of this heterogeneity often plays a crucial role in the prognosis and treatment of the disease. To date, the exact mechanisms and effective treatment strategies of HFmrEF and HFpEF are still poorly understood, but some of the current evidence, from observational studies and analyses of randomized controlled trials, have shown that patients with HFmrEF may benefit more from HFrEF treatment strategies, such as beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, and sacubitril/valsartan. This review summarizes available data from current clinical practice and mechanistic studies in terms of epidemiology, etiology, clinical indicators, mechanisms, and treatments to discuss the potential association between HFmrEF and HFpEF patients.
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http://dx.doi.org/10.3389/fcvm.2021.678614DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8488158PMC
September 2021

Stimuli-Responsive Materials from Ferrocene-Based Organic Small Molecule for Wearable Sensors.

Small 2021 11 5;17(46):e2103125. Epub 2021 Oct 5.

Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study and Department of Chemical and Biological Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Stimuli-responsive crystals capable of energy conversion have emerged as promising materials for smart sensors, actuators, wearable devices, and robotics. Here, a novel ferrocene-based organic molecule crystal (Fc-Cz) that possesses anisotropic piezoelectric, optical, and mechanical properties is reported. It is demonstrated that the new crystal Fc-Cz can be used as an ultrasensitive piezoelectric material in fabricating strain sensors. The flexible sensor made of crystal Fc-Cz can detect small strains/deformations and motions with a fast response speed. Analysis based on density functional theory (DFT) indicates that an external pressure can affect the dipole moment by changing the molecular configuration of the asymmetric single crystal Fc-Cz in the crystalline state, leading to a change of polarity, and thereby an enhanced dielectric constant. This work demonstrates a new artificial organic small molecule for high-performance tactile sensors, indicating its great potential for developing low-cost flexible wearable sensors.
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http://dx.doi.org/10.1002/smll.202103125DOI Listing
November 2021

Structure and mechanism of the γ-glutamyl-γ-aminobutyrate hydrolase SpuA from Pseudomonas aeruginosa.

Acta Crystallogr D Struct Biol 2021 Oct 22;77(Pt 10):1305-1316. Epub 2021 Sep 22.

State Key Laboratory of Medicinal Chemical Biology, Tianjin Key Laboratory of Protein Science and College of Life Sciences, Nankai University, Tianjin 300071, People's Republic of China.

Polyamines are important regulators in all living organisms and are implicated in essential biological processes including cell growth, differentiation and apoptosis. Pseudomonas aeruginosa possesses an spuABCDEFGHI gene cluster that is involved in the metabolism and uptake of two polyamines: spermidine and putrescine. In the proposed γ-glutamylation-putrescine metabolism pathway, SpuA hydrolyzes γ-glutamyl-γ-aminobutyrate (γ-Glu-GABA) to glutamate and γ-aminobutyric acid (GABA). In this study, crystal structures of P. aeruginosa SpuA are reported, confirming it to be a member of the class I glutamine amidotransferase (GAT) family. Activity and substrate-binding assays confirm that SpuA exhibits a preference for γ-Glu-GABA as a substrate. Structures of an inactive H221N mutant were determined with bound glutamate thioester intermediate or glutamate product, thus delineating the active site and substrate-binding pocket and elucidating the catalytic mechanism. The crystal structure of another bacterial member of the class I GAT family from Mycolicibacterium smegmatis (MsGATase) in complex with glutamine was determined for comparison and reveals a binding site for glutamine. Activity assays confirm that MsGATase has activity for glutamine as a substrate but not for γ-Glu-GABA. The work reported here provides a starting point for further investigation of polyamine metabolism in P. aeruginosa.
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http://dx.doi.org/10.1107/S2059798321008986DOI Listing
October 2021

First Measurement of the Absolute Branching Fraction of Λ→pμ^{-}ν[over ¯]_{μ}.

Phys Rev Lett 2021 Sep;127(12):121802

Turkish Accelerator Center Particle Factory Group, Istinye University, 34010 Istanbul, Turkey.

The absolute branching fraction of Λ→pμ^{-}ν[over ¯]_{μ} is reported for the first time based on an e^{+}e^{-} annihilation sample of 10×10^{9}  J/ψ events collected with the BESIII detector at sqrt[s]=3.097  GeV. The branching fraction is determined to be B(Λ→pμ^{-}ν[over ¯]_{μ})=[1.48±0.21(stat)±0.08(syst)]×10^{-4}, which is improved by about 30% in precision over the previous indirect measurements. Combining this result with the world average of B(Λ→pe^{-}ν[over ¯]_{e}), we obtain the ratio {[Γ(Λ→pμ^{-}ν[over ¯]_{μ})]/[Γ(Λ→pe^{-}ν[over ¯]_{e})]} to be 0.178±0.028, which agrees with the standard model prediction assuming lepton flavor universality. The asymmetry of the branching fractions of Λ→pμ^{-}ν[over ¯]_{μ} and Λ[over ¯]→p[over ¯]μ^{+}ν_{μ} is also determined, and no evidence for CP violation is found.
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http://dx.doi.org/10.1103/PhysRevLett.127.121802DOI Listing
September 2021

Strain-Driven Dzyaloshinskii-Moriya Interaction for Room-Temperature Magnetic Skyrmions.

Phys Rev Lett 2021 Sep;127(11):117204

Department of Physics, Beijing Normal University, Beijing 100875, China.

Dzyaloshinskii-Moriya interaction in magnets, which is usually derived from inversion symmetry breaking at interfaces or in noncentrosymmetric crystals, plays a vital role in chiral spintronics. Here we report that an emergent Dzyaloshinskii-Moriya interaction can be achieved in a centrosymmetric material, La_{0.67}Sr_{0.33}MnO_{3}, by a graded strain. This strain-driven Dzyaloshinskii-Moriya interaction not only exhibits distinctive two coexisting nonreciprocities of spin-wave propagation in one system, but also brings about a robust room-temperature magnetic skyrmion lattice as well as a spiral lattice at zero magnetic field. Our results demonstrate the feasibility of investigating chiral spintronics in a large category of centrosymmetric magnetic materials.
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http://dx.doi.org/10.1103/PhysRevLett.127.117204DOI Listing
September 2021

Theoretical Study of O-CH Bond Dissociation Enthalpy in Anisole Systems.

ACS Omega 2021 Aug 19;6(34):21952-21959. Epub 2021 Aug 19.

School of Pharmaceutical Science and Technology, Tianjin University, No. 92 Weijin Road, Naikai District, Tianjin 300072, P. R. China.

Understanding ubiquitous methyl transfer reactions requires a systematic study of thermodynamical parameters that could reveal valuable information about the nature of the chemical bond and the feasibility of those processes. In the present study, the O-CH bond dissociation enthalpies (BDEs) of 67 compounds belonging to phenol/anisole systems were calculated employing the Gaussian-4 (G4) method. Those compounds contain different substituents including alkyl groups, electron-donating groups (EDGs), and electron-withdrawing groups (EWGs). The results show that the bigger branched alkyl groups and EDGs will destabilize the O-CH bond, while EWGs have the opposite effect. A combination of different effects including steric effects, hydrogen bonds, and substituents and their position can achieve around 20 kcal/mol difference compared to the basic phenyl frame. Also, the linear correlation between σ and O-CH BDE can provide a reference for the O-CH BDE prediction. The present study represents a step forward to establish a comprehensive O-CH BDE database to understand the substituent effect and make its contribution to the rational design of inhibitors and drugs.
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http://dx.doi.org/10.1021/acsomega.1c02310DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8412933PMC
August 2021

Direct Measurement of the Branching Fractions B(ψ(3686)→J/ψX) and B(ψ(3770)→J/ψX), and Observation of the State R(3760) in e^{+}e^{-}→J/ψX.

Phys Rev Lett 2021 Aug;127(8):082002

Istanbul Bilgi University, 34060 Eyup, Istanbul, Turkey.

We report a measurement of the observed cross sections of e^{+}e^{-}→J/ψX based on 3.21  fb^{-1} of data accumulated at energies from 3.645 to 3.891 GeV with the BESIII detector operated at the BEPCII collider. In analysis of the cross sections, we measured the decay branching fractions of B(ψ(3686)→J/ψX)=(64.4±0.6±1.6)% and B(ψ(3770)→J/ψX)=(0.5±0.2±0.1)% for the first time. The energy-dependent line shape of these cross sections cannot be well described by two Breit-Wigner (BW) amplitudes of the expected decays ψ(3686)→J/ψX and ψ(3770)→J/ψX. Instead, it can be better described with one more BW amplitude of the decay R(3760)→J/ψX. Under this assumption, we extracted the R(3760) mass M_{R(3760)}=3766.2±3.8±0.4  MeV/c^{2} , total width Γ_{R(3760)}^{tot}=22.2±5.9±1.4  MeV, and product of leptonic width and decay branching fraction Γ_{R(3760)}^{ee}B[R(3760)→J/ψX]=(79.4±85.5±11.7)  eV. The significance of the R(3760) is 5.3σ. The first uncertainties of these measured quantities are from fits to the cross sections and second systematic.
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http://dx.doi.org/10.1103/PhysRevLett.127.082002DOI Listing
August 2021

Linkage of nanosecond protein motion with enzymatic methyl transfer by nicotinamide N-methyltransferase.

Turk J Biol 2021 23;45(3):333-341. Epub 2021 Jun 23.

School of Pharmaceutical Science and Technology, Tianjin University, Tianjin China.

Nicotinamide N-methyltransferase (NNMT), a key cytoplasmic protein in the human body, is accountable to catalyze the nicotinamide (NCA) N-methylation through S-adenosyl-L-methionine (SAM) as a methyl donor, which has been linked to many diseases. Although extensive studies have concerned about the biological aspect, the detailed mechanism study of the enzyme function, especially in the part of protein dynamics is lacking. Here, wild-type nicotinamide N-methyltransferase together with the mutation at position 20 with Y20F, Y20G, and free tryptophan were carried out to explore the connection between protein dynamics and catalysis using time-resolved fluorescence lifetimes. The results show that wild-type nicotinamide N-methyltransferase prefers to adapt a less flexible protein conformation to achieve enzyme catalysis.
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http://dx.doi.org/10.3906/biy-2101-54DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8313939PMC
June 2021

Direct Visualization and Manipulation of Stacking Orders in Few-Layer Graphene by Dynamic Atomic Force Microscopy.

J Phys Chem Lett 2021 Aug 28;12(30):7328-7334. Epub 2021 Jul 28.

Department of Materials Science and Engineering, National University of Singapore, Singapore 117575, Singapore.

Stacking order plays a central role in governing a wide range of properties in layered two-dimensional materials. In the case of few-layer graphene, there are two common stacking configurations: ABA and ABC stacking, which have been proven to exhibit dramatically different electronic properties. However, the controllable characterization and manipulation between them remain a great challenge. Here, we report that ABA- and ABC-stacked domains can be directly visualized in phase imaging by tapping-mode atomic force microscopy with much higher spatial resolution than conventional optical spectroscopy. The contrasting phase is caused by the different energy dissipation by the tip-sample interaction. We further demonstrate controllable manipulation on the ABA/ABC domain walls by means of propagating stress transverse waves generated by the tapping of tip. Our results offer a reliable strategy for direct imaging and precise control of the atomic structures in few-layer graphene, which can be extended to other two-dimensional materials.
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http://dx.doi.org/10.1021/acs.jpclett.1c01579DOI Listing
August 2021

Effect of Loading Frequency Ratio on Multiaxial Asynchronous Fatigue Failure of 30CrMnSiA Steel.

Materials (Basel) 2021 Jul 15;14(14). Epub 2021 Jul 15.

College of Aerospace Engineering, Chongqing University, Chongqing 400044, China.

Multiaxial asynchronous fatigue experiments were carried out on 30CrMnSiA steel to investigate the influence of frequency ratio on fatigue crack initiation and propagation. Test results show that the surface cracks initiate on the maximum shear stress amplitude planes with larger normal stress, propagate approximately tens of microns, and then propagate along the maximum normal stress planes. The frequency ratio has an obvious effect on the fatigue life. The variation of normal and shear stress amplitudes on the maximum normal stress plane induces the crack retardation, and results in that the crack growth length is longer for the constant amplitude loading than that for the asynchronous loading under the same fatigue life ratio. A few fatigue life prediction models were employed and compared. Results show that the fatigue life predicted by the model of Bannantine-Socie cycle counting method, section critical plane criterion and Palmgren-Miner's cumulative damage rule were more applicable.
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http://dx.doi.org/10.3390/ma14143968DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8305907PMC
July 2021

How Do Molecular Motions Affect Structures and Properties at Molecule and Aggregate Levels?

J Am Chem Soc 2021 08 22;143(30):11820-11827. Epub 2021 Jul 22.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.

Molecular motions are essential natures of matter and play important roles in their structures and properties. However, owing to the diversity and complexity of structures and behaviors, the study of motion-structure-property relationships remains a challenge, especially at all levels of structural hierarchy from molecules to macro-objects. Herein, luminogens showing aggregation-induced emission (AIE), namely, 9-(pyrimidin-2-yl)-carbazole (PyCz) and 9-(5-R-pyrimidin-2-yl)-carbazole [R = Cl (ClPyCz), Br (BrPyCz), and CN (CyPyCz)], were designed and synthesized, to decipher the dependence of materials' structures and properties on molecular motions at the molecule and aggregate levels. Experimental and theoretical analysis demonstrated that the active intramolecular motions in the excited state of all molecules at the single-molecule level endowed them with more twisted structural conformations and weak emission. However, owing to the restriction of intramolecular motions in the nano/macroaggregate state, all the molecules assumed less twisted conformations with bright emission. Unexpectedly, intermolecular motions could be activated in the macrocrystals of ClPyCz, BrPyCz, and CyPyCz through the introduction of external perturbations, and synergic strong and weak intermolecular interactions allowed their crystals to undergo reversible deformation, which effectively solved the problem of the brittleness of organic crystals, while endowing them with excellent elastic performance. Thus, the present study provided insights on the motion-structure-property relationship at each level of structural hierarchy and offered a paradigm to rationally design multifunctional AIE-based materials.
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http://dx.doi.org/10.1021/jacs.1c05647DOI Listing
August 2021

Visualization and Manipulation of Solid-State Molecular Motions in Cocrystallization Processes.

J Am Chem Soc 2021 06 21;143(25):9468-9477. Epub 2021 Jun 21.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Department of Chemical and Biomedical Engineering, Institute for Advanced Study, and Guangdong Hong Kong Macro Joint Laboratory of Optoelectronic and Magnetic Functional Materials, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Solid-state molecular motions (SSMM) play a critical role in adjusting behaviors and properties of materials. However, research on SSMM, especially for multicomponent systems, suffers from various problems and is rarely explored. Herein, through collaboration with cocrystal engineering, visualization and manipulation of SSMM in two-component systems, namely, FSBO (()-2-(4-fluorostyryl)benzo[]oxazole)/TCB (1,2,4,5-tetracyanobenzene) and PVBO (()-2-(2-(pyridin-4-yl)vinyl)benzo[]oxazole)/TCB, were realized. The obtained yellow-emissive F/T (FSBO/TCB) cocrystal displayed turn-on fluorescence, and the green-emissive P/T (PVBO/TCB) cocrystal presented redder emission, both of which exhibited an aggregation-induced emission property. At varied pressure and temperature, the grinding mixtures of FSBO/TCB and PVBO/TCB displayed different molecular motions that were readily observed through the fluorescence signal. Notably, even without grinding, FSBO and TCB molecules could move over for 4 mm in a 1D tube. The unique emission changes induced by SSMM were applied in information storage and dynamic anticounterfeiting. This work not only visualized and manipulated SSMM but offered more insights for multicomponent study in aggregate science.
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http://dx.doi.org/10.1021/jacs.1c02594DOI Listing
June 2021

Association of Blood Pressure, White Matter Lesions, and Regional Cerebral Blood Flow.

Med Sci Monit 2021 Jun 21;27:e929958. Epub 2021 Jun 21.

Department of Neurology, The Lianyungang Hospital Affiliated to Xuzhou Medical University, Lianyungang, Jiangsu, China (mainland).

BACKGROUND At present, the association between blood pressure, regional cerebral blood flow, and white matter lesions is not well understood. MATERIAL AND METHODS A total of 147 subjects aged from 40 to 80 years were assessed by the Fazekas score for white matter lesions, CT perfusion imaging for regional cerebral blood flow, and 24-h ambulatory blood pressure monitoring for blood pressure level and rhythm. Logistic regression analysis was used to obtain the odds ratio and 95% confidence interval between Fazekas scores and relevant factors. The relationship between blood pressure index and regional cerebral blood flow was analyzed through cubic curve estimation. RESULTS Fazekas score was negatively correlated with regional cerebral blood flow (r=-0.801; r=-0.831, P<0.001). For subcortical lesion, the regional cerebral blood flow of Fazekas grade 0 was 1.976 times that of Fazekas grade 3 (OR=1.976, 95% CI=1.576-2.477), and for periventricular lesion, the regional cerebral blood flow of Fazekas grade 0 was 2.034 times that of Fazekas grade 3 (OR=2.034, 95% CI=1.602-2.583). Increased nighttime systolic blood pressure may be more dangerous (OR=1.112, 95% CI=1.059-1.169). The day-night systolic blood pressure ratio (OR=0.801, 95% CI 0.711-0.902) and the day-night diastolic blood pressure ratio (OR=0.876, 95% CI 0.807-0.950) were significantly correlated with Fazekas score. CONCLUSIONS The decrease of white matter regional cerebral blood flow caused by hypertension is probably one of the important causes of white matter lesions. Patients with white matter lesions should also pay attention to the rhythm of blood pressure when controlling hypertension, especially if their blood pressure is too high or too low at night.
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http://dx.doi.org/10.12659/MSM.929958DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8230251PMC
June 2021

How to Manipulate Through-Space Conjugation and Clusteroluminescence of Simple AIEgens with Isolated Phenyl Rings.

J Am Chem Soc 2021 Jun 11;143(25):9565-9574. Epub 2021 Jun 11.

Department of Chemistry, Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction and Institute for Advanced Study, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong 999077, China.

Apart from the traditional through-bond conjugation (TBC), through-space conjugation (TSC) is gradually proved as another important interaction in photophysical processes, especially for the recent observation of clusteroluminescence from nonconjugated molecules. However, unlike TBC in conjugated chromophores, it is still challenging to manipulate TSC and clusteroluminescence. Herein, simple and nonconjugated triphenylmethane (TPM) and its derivatives with electron-donating and electron-withdrawing groups were synthesized, and their photophysical properties were systematically studied. TPM was characterized with visible clusteroluminescence due to the intramolecular TSC. Experimental and theoretical results showed that the introduction of electron-donating groups into TPM could red-shift the wavelength and increase the efficiency of clusteroluminescence simultaneously, due to the increased electronic density and stabilization of TSC. However, TPM derivatives with electron-withdrawing groups showed inefficient or even quenched clusteroluminescence caused by the vigorous excited-state intramolecular motion and intermolecular photoinduced electron transfer process. This work provides a reliable strategy to manipulate TSC and clusteroluminescence.
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http://dx.doi.org/10.1021/jacs.1c03882DOI Listing
June 2021

Decoding Spatial Memory Retrieval in Cubical Space Using fMRI Signals.

Front Neural Circuits 2021 18;15:624352. Epub 2021 May 18.

Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin, China.

The way spatial memory retrieval is represented in the brain remains unclear to date. Previous studies have displayed a hippocampus-centered navigation network using functional magnetic resonance imaging (fMRI) analysis. There have been some studies on the representation of navigation behavior by signal distribution patterns, but only in the hippocampus and adjacent structures. In this study, we aimed to determine (1) the brain regions that represent information in both intensity and distribution patterns during spatial memory retrieval and (2) whether the patterns of neural responses represent spatial memory retrieval behavior performance. Both univariate analysis [general linear model (GLM)] and multivariate pattern analysis (MVPA) were employed to reveal the spatial distributions of brain responses elicited by spatial memory retrieval. Correlation analyses were performed to detect the correspondences between brain responses and behavior performance. We found that spatial memory retrieval occurred in widespread brain regions, including the bilateral hippocampi, bilateral superior frontal gyrus, bilateral superior parietal lobules, bilateral occipital lobes, and cerebellum. The amplitude of activation in the left hippocampus showed a significant negative correlation ( = -0.46, = 0.039) with the number of task completions. Additionally, within-subject classification accuracies based on the blood oxygenation level-dependent (BOLD) signal patterns of the right middle temporal gyrus (rMTG) rostral areas in the Brainnetome Atlas showed a significant positive correlation ( = 0.78, < 0.0001) with retrieval accuracy. In summary, our findings have implications for understanding the separation between navigational and non-navigational states and emphasizing the utility of MVPA in the whole brain.
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http://dx.doi.org/10.3389/fncir.2021.624352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168467PMC
January 2022

An Air-Stable Organic Radical from a Controllable Photoinduced Domino Reaction of a Hexa-aryl Substituted Anthracene.

J Org Chem 2021 Jun 25;86(11):7359-7369. Epub 2021 May 25.

Department of Chemistry, The Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and Reconstruction, Institute for Advanced Study, Department of Chemical and Biological Engineering, Division of Life Science, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.

Air-stable organic radicals and radical ions have attracted great attention for their far-reaching application ranging from bioimaging to organic electronics. However, because of the highly reactive nature of organic radicals, the design and synthesis of air-stable organic radicals still remains a challenge. Herein, an air-stable organic radical from a controllable photoinduced domino reaction of a hexa-aryl substituted anthracene is described. The domino reaction involves a photoinduced [4 + 2] cycloaddition reaction, rearrangement, photolysis, and an elimination reaction; H/C NMR spectroscopy, high resolution mass spectrometry, single-crystal X-ray diffraction, and EPR spectroscopy were exploited for characterization. Furthermore, a photoinduced domino reaction mechanism is proposed according to the experimental and theoretical studies. In addition, the effects of employing push and pull electronic groups on the controllable photoinduced domino reaction were investigated. This article not only offers a new blue emitter and novel air-stable organic radical compound for potential application in organic semiconductor applications, but also provides a perspective for understanding the fundamentals of the reaction mechanism on going from anthracene to semiquinone in such anthracene systems.
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http://dx.doi.org/10.1021/acs.joc.1c00233DOI Listing
June 2021
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