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Herein, we report a concise method for the preparation of functionalized cyclopentadienyl rhodium complexes via Suzuki–Miyaura cross-coupling. We successfully converted 2,3,4,5-tetramethylcyclopent-2-en-1-one into the corresponding cyclopentadienylboronic acid pinacol ester, which could be used as a coupling partner with aryl halides. Several functionalized cyclopentadienyl rhodium complexes were synthesized in two steps from readily available aryl bromides. We also demonstrated the rapid synthesis of a novel chiral cyclopentadienyl rhodium complex that could be used as a precatalyst for an asymmetric C–H functionalization reaction.

The atom transfer radical addition (ATRA) of bromodifluoroacetamides to arylalkynes and terminal alkenes was conducted using von Wangelin's Co catalyst system (CoBr2/1,2-bis(diphenylphosphino)benzene/Zn) in acetone/H2O at 30 °C to afford the corresponding functionalized difluoroacetamides in 33–89% yields. Moreover, the Co catalyst was successfully applied to the tandem addition/cyclization of 1,6-diene and -enyne substrates and intramolecular ATRA of N-allyl and N-propargyl bromodifluoroacetamides, significantly expanding the scope of radical difluoroalkylation.

Terahertz (THz) waves have attracted attention as carrier waves for next-generation wireless communications (6G). Electronic THz emitters are widely used in current mobile communications; however, they may face technical limitations in 6G with upper-frequency limits. We demonstrate wireless communication in a 560-GHz band by using a photonic THz emitter based on photomixing of a 560-GHz-spacing soliton microcomb in a uni-travelling carrier photodiode together with a THz receiver of Schottky barrier diode. The on-off keying data transfer with 2-Gbit/s achieves a Q-factor of 3.4, thus, satisfying the limit of forward error correction., Comment: 17 pages, 4 figure

Digital holography (DH) is a powerful tool for surface profilometry of objects with sub-wavelength precision. In this article, we demonstrate full-cascade-linked synthetic-wavelength DH (FCL-SW-DH) for nanometer-precision surface metrology of millimeter-size stepped objects. 300 modes of optical frequency comb (OFC) with different wavelengths are sequentially extracted at a step of mode spacing from a 10GHz-spacing, 3.72THz-spanning electro-optic modulator OFC (EOM-OFC). The resulting 299 synthetic wavelengths and a single optical wavelength are used to generate a fine-step wide-range cascade link covering within a wavelength range of 1.54 um to 29.7 mm. We determine the 0.1000mm-stepped surface with axial uncertainty of 6.1 nm within the maximum axial range of 14.85 mm., Comment: 22 pages, 6 figures

Herein, we report a method for the generation of vinylallenes via cobalt/photoredox dual-catalysis-enabled formal 1,8-acyloxy migration of 1,6-diynyl esters. We demonstrated a 1,8-acyloxy migration/6π-electrocyclization cascade using (hetero)aryl-substituted 1,6-diynyl esters as substrates, leading to the formation of arenol derivatives. Several control experiments suggested that the β-oxygen elimination of a cobaltacyclopentadiene intermediate enabled formal 1,8-acyloxy migration to generate the vinylallene. We also applied this method to cascade cyclizations involving [2 + 2] or [4 + 2] cycloadditions to furnish various polycyclic molecules.

Herein, we report dual cobalt and photoredox catalysis enabled [2+2+2] cycloaddition of enediynes to produce tricyclic cyclohexadienes bearing a quaternary bridgehead carbon. A variety of enediynes were used, and the corresponding cyclohexadienes were obtained in good to high yields. The use of a chiral ligand, (S)-Segphos, enabled a highly enantioselective reaction allowing access to highly enantio-enriched cyclohexadienes.

We have synthesized a cyan fluorescent boron complex based on a tridentate imidazo[1,5-a]pyridine ligand. The boron complex was found to have potential applications as not only a chiroptical material but also a heavy-atom-free mitochondria-targeted photosensitizer for cancer treatment.

Herein, we report a Rh-catalyzed asymmetric [2+2+2] cycloaddition of ene-yne-yne enediynes to generate enantio-enriched tricyclic cyclohexadienes bearing a quaternary bridgehead carbon. We found that the Rh-Phanephos complex is an appropriate catalyst for the cycloaddition of enediynes bearing an unsubstituted propiolate terminus, whereas Rh-biaryl bisphosphine catalysts, which have been widely used for asymmetric cycloadditions of alkynes and alkenes, are not applicable for the reaction of such enediynes. Several control experiments suggest that the reaction using the Rh-Phanephos complex exclusively proceeds via a rhodacyclopentadiene intermediate, unlike when using a Rh-biaryl bisphosphine complex that can form a rhodacyclopentadiene intermediate as well as a rhodacyclopentene intermediate in a substrate-dependent manner.

Quantitative assessment of healing after tendon injury is important for orthopedic practice. Although histological and mechanical recovery are assessed by histological staining and tensile testing respectively, both tests are destructive and invasive, making it difficult to be applied to single sample. Here, as a non-destructive and less invasive approach for quantitative assessment of tendon healing, we applied Fourier-transform second-harmonic-generation (FT-SHG) microscopy to an animal model of tendon healing. FT-SHG microscopy enables orientation analysis of collagen fibers independently of the SHG image brightness. The extracted FT-SHG parameter showed a significant difference between the healing sample and the control sample, indicating the potential for quantitative parameter of histological recovery. More importantly, the FT-SHG parameter indicated good correlation (coefficient of determination, R2 = 0.62) with the Young's modulus obtained by tensile testing of the same sample. These results indicate the potential of the proposed method for quantitative evaluation of both histological and mechanical recovery after tendon injury.

Trifluoromethylation of furfural using the Ruppert–Prakash reagent (TMSCF3) and subsequent photo-Achmatowicz reaction afforded 6-hydroxy-2-(trifluoromethyl)-2H-pyran-3(6H)-one. After acetylation, the resultant 6-acetoxy-2-(trifluoromethyl)-2H-pyran-3(6H)-one was transformed into various 1-(trifluoromethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-one derivatives through a base-mediated oxidopyrylium [5 + 2] cycloaddition. The reactivity and selectivity of the 2-trifluoromethylated oxidopyrylium species toward [5 + 2] cycloaddition were analyzed using density functional theory calculations.

The palladium-catalyzed reaction of 4-iodo-2-quinolones with diarylacetylenes in the presence of Ag2CO3 as a base in N,N-dimethylformamide (DMF) at 100 °C afforded unprecedented polyfused 2-quinolo...

The Fe(OTf)3-catalyzed Friedel–Crafts reaction of 2,2-difluoro-1-arylethyl phosphates with electron-rich (hetero)arenes afforded difluoromethylated diarylmethanes. Control experiments showed that Fe(OTf)3 behaves as the Lewis acid, and that the phosphate leaving group and o- or p-alkoxy substituents on the substrates are necessary for the Fe(OTf)3-catalyzed reaction to proceed under mild conditions.

Herein, we report the synthesis of 1-(difluoromethyl)alkenes via a palladium-catalyzed reaction of difluoromethyl-substituted allylic phosphates with 1,3-dicarbonyl compounds using PdCl2(PPh3)2 as ...

Rapid, sensitive detection of biomolecules is important for improved testing methods for viruses as well as biomarkers and environmental hormones. For example, testing for SARS-CoV-2 is essential in the fight against the COVID-19 pandemic. Reverse-transcription polymerase chain reaction (RT-PCR) is the current standard for COVID-19 testing; however, it is hampered by the long testing process. Shortening the testing process while achieving high sensitivity would facilitate sooner quarantine and thus presumably prevention of the spread of SARS-CoV-2. Here, we aim to achieve rapid, sensitive detection of the SARS-CoV-2 nucleocapsid protein by enhancing the performance of optical biosensing with a dual-comb configuration of optical frequency combs. The virus-concentration-dependent optical spectrum shift is transformed into a photonic RF shift by frequency conversion between the optical and RF regions, facilitating mature electrical frequency measurements. Furthermore, active-dummy temperature-drift compensation enables very small changes in the virus-concentration-dependent signal to be extracted from the large, variable background signal. This dual-comb biosensing technique has the potential to reduce the COVID-19 testing time to 10 min while maintaining sensitivity close to that of RT-PCR. Furthermore, this system can be applied for sensing of not only viruses but also various biomolecules for clinical diagnosis, health care, and environmental monitoring., 42 pages, 6 figures, 2 tables

OBJECTIVES Even after transplantation of favourable donor lungs, some recipients require prolonged weaning from mechanical ventilation, indicating a poor prognosis. We investigated the effects of prolonged mechanical ventilation (PMV) for >14 days on the recovery and survival of patients who underwent cadaveric lung transplantation in relation to their physical traits. METHODS We retrospectively reviewed patients who underwent cadaveric lung transplantation (age ≥15 years) at a single centre between April 2015 and December 2020 and classified them into PMV and non-PMV groups (>14 and ≤14 days of mechanical ventilation postoperatively, respectively). The factors predicting PMV comprised clinical factors (e.g. marginal donor) and physical features, namely flat chest, narrow fourth intercostal space (length, 40% and sarcopenia, according to the logistic regression analysis. The log-rank test was used to examine the association between TMOR >40% and 3-year prognosis. RESULTS The PMV group comprised 17 (33%) of 51 recipients. Multivariable logistic analysis showed that the TMOR >40% (odds ratio, 7.3; 95% confidence interval, 1.3–40.1; P = 0.023) was an independent preoperative predictive factor for PMV postoperatively. Stepwise analysis revealed intraoperative extracorporeal membrane oxygenation and reoperation as postoperative predictive factors in addition to TMOR >40%. Recipients with TMOR >40% had significantly worse 3-year survival than other recipients (71.2% vs 100.0%, respectively; P = 0.008). CONCLUSIONS Recipients with a TMOR >40% may be long-term ventilator dependent and have a poor prognosis.

Nondestructive testing of concrete materials is essential in civil engineering to maintain social infrastructure such as buildings or bridges. In this study, we constructed an ultralow-frequency, ultranarrow-bandwidth, coherent terahertz (THz) imaging system based on THz time-domain spectroscopy (THz-TDS). Based on its ultralow-frequency-localized THz wave and coherent detection, the present system achieved a wide dynamic range of THz power over 100 dB at 0.046 THz, which is appropriate to measure the mortar material. The achieved dynamic range of the THz power was 59 dB larger than that of a commercialized THz-TDS system and 49 dB larger than that of an ultralow-frequency noncoherent THz imaging system equipped with a high-power electric THz source. Ultimately, the proposed system could visualize the inner structure of a mortar sample with a thickness of 10 mm, and the present system can investigate a mortar sample with a thickness of over 130 mm. The proposed method is an attractive tool for non-destructive testing of thick concrete structures characterized by non-invasiveness and non-contact remoteness.

The palladium‐catalyzed reaction of 4‐iodo‐2‐quinolones with activated alkynes was investigated. Cyclopenta[de ]quinoline‐2(1 H )‐ones and/or phenanthridine‐6(5 H )‐ones were obtained through [3+2] annulation involving aromatic C−H activation or [2+2+2] annulation involving vinylic C−H activation, respectively. Reasonable mechanisms for the formation of these annulation products have been proposed based on density functional theory calculations., ファイル公開：2021-03-27

The rhodium-catalyzed cycloisomerization of ester-tethered 1,6-diynes bearing a cyclopropanol moiety produced tetralone/exocyclic diene hybrid molecules with thermodynamically unfavorable alkene geometry. The results of control experiments and density functional theory calculations suggest that the ester tether plays an important role in the efficiency of E/Z isomerization processes.

We have synthesized a series of quaternized imidazo[1,2-a]pyridines in three steps from commercially available reagents. These compounds exhibit blue fluorescence emission at around 425 nm with good quantum yields. In addition, one specific compound was found to work as not only a two- and three-photon excitable mitochondria imaging agent, but also a therapeutic agent upon continuous irradiation conditions.

We suppress the temperature drift in the refractive-index-sensing optical frequency comb (RI-sensing OFC) by taking the difference of repetition frequency between an active RI-sensing OFC and a dummy one in the mechanical-sharing dual-fiber-cavity configuration.

We demonstrate a compact, mechanical-sharing dual-comb fiber laser based on an all-polarization-maintaining configuration and a micro-optic-component of saturable absorber mirror. This setup realizes a high relative stability with a standard deviation of 0.6 Hz.

Various studies have so far been conducted on the strong coupling interaction between light and matter in microcavities. Although most of them report on the coupling between the electric field and the electric dipole, the coupling between the magnetic field and the magnetic dipole is rarely reported. In this study, we investigated the strong coupling interaction between a magnetic field and a magnetic dipole using a Fabry–Pérot microcavity structure in the THz region consisting of wire grid (WG) mirrors and rectangular hole (RH) metamaterials. Here, the RH is well known as a magnetic current type slot antenna, which can be regarded as a magnetic dipole. To verify this concept, we analyzed the transmission properties of WG, RH, and a microcavity consisting of WG and RH (WGRH) using the transmission line theory. Consequently, we found that in this WGRH, normal mode splitting occurs, and anti-crossing behavior is observed in the dispersion relation. The samples were designed using the finite difference time-domain method and were fabricated via photolithography. We measured the transmission spectrum of the fabricated samples using THz time-domain spectroscopy. Finally, we observed a splitting of the transmission peak owing to mode coupling between the magnetic field and the magnetic dipole in WGRH.

We construct a full-field phase-shifting terahertz digital holography (PS-THz-DH) system by use of a THz quantum cascade laser and an uncooled, 2D micro-bolometer array. The PS-THz-DH enables us to separate the necessary diffraction-order image from unnecessary diffraction-order images without the need for spatial Fourier filtering, leading to suppress the decrease of spatial resolution. 3D shape of a visibly opaque object is visualized with a sub-millimeter lateral resolution and a sub-µm axial resolution. Also, the digital focusing of amplitude image enables the visualization of internal structure with the millimeter-order axial selectivity. Furthermore, the internal stress distribution of an externally compressed object is visualized from the phase image. The demonstrated results imply a possibility for non-destructive inspection of visibly opaque non-metal materials.

We report a near-infrared surface plasmon resonance (SPR) system to achieve highly sensitive, unlabeled detection of the SARS-CoV-2 nucleocapsid protein antigen. Use of the near-infrared light in SPR makes the SPR dip of the angular spectrum sharp and causes a large change of the reflected light intensity at a fixed incident angle. The present SPR system achieves the resolution of 10−5 refractive index unit in the refractive index measurement of glycerol solution samples. Additionally, we measured the nucleocapsid protein antigen of SARS-CoV-2 down to a molar concentration of 1 fM by immobilizing its corresponding antibody on the SPR sensor surface. This demonstration indicates a high potential of the present system for highly sensitive biosensing in medical diagnostics.

GPR85 is a member of the G protein-coupled receptor and is a super-conserved receptor expressed in the brain sub-family (SREB) with GPR27 and GPR173. These three receptors are “orphan receptors”; however, their endogenous ligands have not been identified. SREB has garnered the interest of many scientists because it is expressed in the central nervous system and is evolutionarily conserved. In particular, brain mass is reported to be increased and learning and memory are improved in GPR85 knockout mice (Matsumoto et al., 2008). In this study, we characterized newly synthesized compounds using a GPR85-Gsα fusion protein and the [35S]GTPγS binding assay and identified novel GPR85 inverse-agonists with IC50 values of approximately 1 µM. To analyze the neurochemical character of the compounds and investigate the physiological significance of GPR85, we used cerebellar Purkinje cells expressing GPR85 and an electrophysiological technique. Based on the results, the inverse-agonist compound for GPR85 modulated potassium channel opening. Together with the results of previous gene analysis of GPR85, we expect that the development of the GPR85 ligand will provide new insights into a few types of neurological disorders.