bluuebunny/crossref_metadata_2025_split huggingface dataset:
Substituent Effects in the 1,1-Diphenylcarbenium Systems: Hydration and Bromination of 1,1-Diphenylethylenes
Authors: Fujio Mizue , Rappoport Zvi , Uddin Md Khabir , Kim Hyun-Joong , Tsuno Yuho 
Published: January 2003

Abstract
Substituent effects log (kXY/kHH)Br on the bromination of 1,1-diarylethylenes were analyzed in comparison with those log (kXY/kHH)OPNB in the solvolysis of 1,1-diarylethyl p-nitrobenzoates. The non-linearity and non-additivity were significant in both cases. While an extended Brønsted relationship against ΔpKBH+ for diarylethylenes holds in the latter process, of particular importance is the finding of a precise linear correlation between the bromination and solvolysis for the whole substituents; log (kXY/kHH)OPNB = 1.07 log (kXY/kHH)Br − 0.83 ΔσR+, where the ΔσR+ is the Yukawa–Tsuno resonance parameter. This relationship can be rewritten in the form of an extended Brønsted correlation: log (kXY/kHH)Br = α [log KXY/KHH]Br, where [log KXY/KHH]Br = −ΔpKBH+ + 0.81 ΔσR+, for the thermodynamic stabilities of the intermediate in the bromination. The constant α coefficient should suffice as convincing evidence for the absence of a coordinate shift of the transition state that is induced by varying substituents in the bromination process. The additional contribution of 0.81 ΔσR+ should be ascribed to the differential cationic charge at the benzylic position in the bromination transition state; a constant coefficient indicates a fixed position of the bromination transition state, irrespective of the fixed-Y subset.
Preparation of Hexakis(6-O-mesitylsulfonyl)cyclomaltooctaoses and Structural Validation of the Four Isomers Using Heteronuclear Multiple Bond Correlation Spectroscopy
Authors: Yamamura Hatsuo , Miyachi Sadaichi , Kano Kazuaki , Araki Shuki , Lee Kenichi , Kawai Masao , Ueyama Norikazu 
Published: January 2003

Abstract
Four cyclomaltooctaose derivatives 1a–d, which possess six mesitylsulfonyloxy groups on their C(6) atoms, were prepared. The assignment of the regiosiomers was performed by observing the long-range coupling through a glycoside linkage between H(1′) –C(4) and C(1′) –H(4) using a heteronuclear multiple-bond correlation (HMBC) method.
Biotransformation of Cycloalkanediones by Caragana chamlagu
Authors: Chai Wen , Sakamaki Hiroshi , Kitanaka Susumu , Horiuchi C Akira 
Published: January 2003

Abstract
The biotransformation of alkylcycloalkanediones using suspension plant cultured-cells of Caragana chamlagu gave oxo carboxylic acids by oxidative cleavage. 5,6-Dioxoheptanoic acid was obtained in high yield (95%) in a short time (7 h) from 2-methyl-1,3-cyclohexanedione. However, 1,2- and 1,4-cycloalkanediones were reduced stereoselectively and trans-1,2-cyclohexanediol and trans-1,4-cyclohexanediol were obtained, respectively. The mechanism of the oxidative cleavage of alkylcycloalkanediones is also discussed.
Synthesis and β-Hydrogen Elimination of Water-Soluble Dialkylplatinum(II) Complexes in Water
Authors: Komiya Sanshiro , Ikuine Miho , Komine Nobuyuki , Hirano Masafumi 
Published: January 2003

Abstract
Water-soluble cis-dialkylplatinum(II) complexes cis-[PtR2L2] (L2 = 2 TPPTS, 2 THMP, DHMPE; R = Me, Et, Ph) have been prepared by ligand displacement reactions of [PtR2(1,5-COD)] with L2. They are stable in water; the diethylplatinum(II) complexes cis-[PtEt2(TPPTS)2] undergo preferential disproportionation of the ethyl groups in water, giving ethylene and ethane in 1 : 1 ratio via β-hydrogen elimination in preference to protonolysis at 80 °C. A retardation effect of added free TPPTS on the reaction rate and a deuterium labelling study suggest a mechanism involving prior dissociation of TPPTS for reversible β-hydrogen elimination.
Asymmetric Cyclopropanation and Aziridination Reactions of Olefins Catalyzed by Cu(I)-Binaphthyldiimine Complexes
Authors: Suga Hiroyuki , Kakehi Akikazu , Ito Suketaka , Ibata Toshikazu , Fudo Tomomi , Watanabe Yuzuru , Kinoshita Yoshinori 
Published: January 2003

Abstract
The chiral Cu(I)-N,N′-bis(2,6-dichlorobenzylidene)-1,1′-binaphthyl-2,2′-diamine complex was found to be an efficient catalyst for asymmetric cyclopropanation and aziridination reactions of olefins with l-menthyl diazoacetate and [N-(p-tolylsulfonyl)imino]phenyliodinane, respectively. Among mono- and disubstituted olefins, 1,1-diarylethylenes showed extremely high enantioselectivities (up to 98% ee) in the cyclopropanation reactions in the presence of a chiral Cu(I)-catalyst (2 mol%). In the case of aziridination reactions catalyzed by the same Cu(I)-catalyst (10 mol%), the reaction of trans-substituted 3-aryl-2-propenoates and 1-substituted trans-3-aryl-2-propen-1-ones showed satisfactory results in term of the enantioselectivities (up to 98% ee).
Photodeoxygenation and α-Cleavage Reactions of Selenoxides
Authors: Yamazaki Yuko , Tsuchiya Takahiro , Hasegawa Tadashi 
Published: January 2003

Abstract
Upon UV-irradiation, diphenyl and dibenzyl selenoxides underwent deoxygenation and α-cleavage competitively to give selenides, and diselenides and others, respectively. A mechanism of bimolecular photodeoxygenation is proposed, since the yields of the photoproducts were dependent on the initial concentration of the selenoxides.
A Novel Approach to Furopyrimidinones Using Dry Media
Authors: Kidwai Mazaahir , Rastogi Shweta , Venkataramanan R 
Published: January 2003

Abstract
An environmentally benign approach to the synthesis of furopyrimidin-4(3H)-one under microwave irradiation (MWI) using an inorganic solid support for catalytic activity as well as an energy-transfer medium is described. The reaction time can be decreased from hours to minutes along with a yield enhancement. In addition, the differential activity of various solid supports was studied for a reaction which enables one to accomplish the one-pot synthesis of the required product via the 2-aminofuran-3-carbonitrile intermediate.
First Syntheses of Iodinated 1,6-Dithiapyrene Derivatives
Authors: Morita Yasushi , Miyazaki Eigo , Toyoda Jiro , Nakasuji Kazuhiro 
Published: January 2003

Abstract
An improved synthetic method of 1,6-dithiapyrene (DTPY) was found with a practical yield in a reproducible manner. Iodinated DTPY derivatives were prepared as new donor molecules, and the crystal structure of 2,7-diiodoDTPY was clarified by an X-ray structure analysis.
Electrooxidative Formation of 1,2-Diaroylcyclopropanes from 1,3-Diaroylpropanes in the Presence of KI
Authors: Okimoto Mitsuhiro , Takahashi Yukio , Kakuchi Toyoji 
Published: January 2003

Abstract
Various 1,2-diaroylcyclopropanes were obtained in good yields by the indirect electrochemical oxidation of 1,3-diaroylpropanes in the presence of catalytic amounts of KI under very mild conditions.
Cation Complexation, Photochromism, and Aggregation of Copolymers Carrying Crown Ether and Spirobenzopyran Moieties at the Side Chains
Authors: Keiichi Kimura , Nakamura Makoto , Sakamoto Hidefumi , Uda Ryoko Mizutani , Sumida Miwa , Yokoyama Masaaki 
Published: January 2003

Abstract
Methacrylate monomers containing monoaza-12-crown-4 and spirobenzopyran moieties were copolymerized to obtain polymers carrying their moieties at the side chains. The crown ether-spiropyran polymers can bind alkali metal ions with their crown ether moiety in the selectivity order of Na+ &gt; K+ &gt; Li+. The spirobenzopyran moiety, on the other hand, undergoes UV-light-induced isomerization from its spiropyran to the merocyanine form, leading to merocyanine aggregate formation. The metal-ion complexation of the crown ether moiety enhanced interpolymer merocyanine aggregation by extending the polymer chain on the basis of the electrostatic repulsion between the complexed metal ions. Thus, tetrahydrofuran solutions of a crown ether-spiropyran copolymer with 1 : 1 composition of the moieties led to significant polymer precipitation on UV irradiation in the presence of an alkali metal ion, especially Li+. The photochromism and aggregate formation were studied in detail by absorption and fluorescence spectrometry and by light scattering measurements.
Fe2O3 Particles Coated with Silica Using TEOS
Authors: Sato Satoshi , Takahashi Ryoji , Sodesawa Toshiaki , Tanaka Rieko 
Published: January 2003

Abstract
Fine particles of SiO2-coated Fe2O3 were prepared by depositing silica on an iron(III) hydroxide precipitate using tetraethoxysilane (TEOS). The silica deposition proceeded under mild conditions at 20 °C; crystallization hardly occurred and silica loading was controlled by the amount of TEOS charged, whereas the precipitate crystallized to a mixture of FeO(OH) and α-Fe2O3 under hydrothermal conditions. The specific surface area of the SiO2-coated Fe2O3 increased with silica loading, and exceeded 280 m2 g−1 even after calcination at 500 °C. The silicate species deposited on the precipitate of iron(III) hydroxide prevented the primary particles from agglomerating during calcination, resulting in the high surface area and hard reducibility of the SiO2-Fe2O3.
Enantioselective Carbonyl-Ene Reaction of Glyoxal Derivatives Catalyzed by Cationic 3-Oxobutylideneaminatocobalt(III) Complexes
Authors: Kezuka Satoko , Kogami Youichi , Ikeno Taketo , Yamada Tohru 
Published: January 2003

Abstract
Optically active 3-oxobutylideneaminatocobalt(III) complexes were designed for the catalytic enantioselective carbonyl-ene reaction. Varieties of counter anions of cationic cobalt(III) complexes were screened and hexafluoroantimonate was found to be the most effective. In the presence of cobalt(III) hexafluoroantimonate complex 1f, the enantioselective carbonyl-ene reaction of various alkenes with glyoxal derivatives was carried out to afford the corresponding homoallylic alcohols in high yields and with high enantioselectivities. Even in the presence of 0.2 mol% cobalt(III) complexes, the reaction proceeded in high yield and with maintained high enantioselectivity. The absolute configuration of the optically active product was determined and a reasonable explanation for the enantioselection in the present carbonyl-ene reaction catalyzed by the cobalt complex was proposed.
An Extended Fano–DeVoe Polarizability Theory Similar to the Bayley–Nielsen–Schellman Secular Matrix Method: CD Calculations of Polypeptides Having α-Helix, β -Sheet, and β -Turn Structures
Authors: Ito Hirotoshi 
Published: January 2003

Abstract
We have expanded the previous Bayley–Nielsen–Schellman type polarizability theory so as to involve a new diagonal type of CAE (Condon, Alter, Eyring) interaction energy as {(the previous diagonal type of CAE interaction energy) − (the electrostatically corrected ground state energy)}, which corresponds to the term pointed out by Misra in his review article. For the CD and UV band shape functions which were previously derived in a different way, we have newly rederived the polymer CD and UV band shape functions by making use of the Green’s function method, starting from the well-known text book by Eyring et al. For a monomer polarizability tensor, the two most often used Lorentzian and Gaussian band approximations will be studied together with practically necessary relationships on the bandwidths.
The theory has been applied to the CD and UV absorption calculations on polypeptides. Previously, unless one scaled the earlier diagonal type of CAE interaction energy, poor predictions were then obtained, especially for the β-sheet polypeptides as well as the small α-helix and β-turn tripeptides. Now, using the new diagonal type of CAE interaction energies, promising CD results have been obtained together with reasonable UV spectral shifts.
Equation of State for Free Energy of Homogeneous Nucleation Derived by Monte Carlo Simulations
Authors: Yamada Yuri , Kataoka Yosuke 
Published: January 2003

Abstract
We performed Monte Carlo simulations for the homogeneous nucleation on supersaturated Lennard–Jones vapor phase to estimate the equation of state for free energy of the nucleation. The calculations were performed on each system with a fixed number of particles. The initial configuration was distorted cubic lattice. The sample was cooled to low temperature, where all particles become a cluster. In the second stage it was heated enough to vaporize; the monomer phase was obtained. In the third run, the stabilized cluster was heated under the condition that the cluster was not allowed to decompose. In the last run, the system was cooled from initial monomer phase with a condition that the particles were not allowed to make any connections. Helmholtz free energies of the cluster and the monomer phase were obtained by thermodynamic integration. The obtained size of critical nucleus was comparable to the results of the molecular dynamics simulation.
Ethylenedioxy-Containing Tetrathiapentalene Derivative with Ethylthio Chains, C2TEO-TTP
Authors: Kimura Shinya , Nii Hirofumi , Kurai Hiroyuki , Takeuchi Tomoaki , Katsuhara Mao , Mori Takehiko 
Published: January 2003

Abstract
A new oxygen-containing π-electron donor having ethylthio chains, C2TEO-TTP (2-[4,5-bis(ethylthio)-1,3-dithiol-2-ylidene]-5-(4,5-ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene), has been synthesized. Single-component C2TEO-TTP forms a β′-like dimerized structure. The 2 : 1 salts with PF6−, ClO4−, and AsF6− have a uniform β-type structure isostructual to the ethylenedithio analog, (C2TET-TTP)2ClO4, and are metallic down to liquid helium temperatures. On the other hand, (C2TEO-TTP)2Au(CN)2 has dimeric donor arrangement, and shows hysteretic temperature dependence of the conductivity.
Structural and Electrical Properties of Novel Molecular Conductors Based on Extended-TTF Donors BDT-TTP and I− Anions
Authors: Cui HengBo , Otsuka Takeo , Kobayashi Akiko , Misaki Yohji , Kobayashi Hayao 
Published: January 2003

Abstract
With the aim of developing organic conductors with new types of molecular arrangements, some organic conductors composed of elongated π donors BDT-TTP (2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) and simple I− anions were prepared by electrocystallization. The crystal of (BDT-TTP)3I has a very unique three-dimensional donor arrangement, where six BDT-TTP molecules are crystallographically independent. Despite the three-dimensional intermolecular short S···S network, the examination of C=C bond lengths of six BDT-TTP molecules indicates an inhomogeneous charge distribution, which is unfavorable for the formation of metallic bands. The resistivity measurements showed the system to be a semiconductor with a very small activation energy. On the other hand, the needle-shaped crystal has β-type donor arrangement and 2 : 1 stoichiometry. The crystal of β-(BDT-TTP)2I retains its metallic state down to 2 K. Though an open Fermi surface was obtained by tight-binding band calculation, the fairly strong two-dimensionality of the electronic structure was suggested.
Operative vs Nonoperative Management of Unstable Medial Malleolus Fractures
Authors: Carter Thomas H. , Oliver William M. , Bell Katrina R. , Graham Catriona , Duckworth Andrew D. , White Timothy O. 
Published: January 2024

ImportanceUnstable ankle fractures are routinely managed operatively. However, because of soft tissue and implant-related complications, recent literature has reported on the nonoperative management of well-reduced medial malleolus fractures after fibular stabilization, but with limited evidence supporting the routine application.ObjectiveTo assess the superiority of internal fixation of well-reduced (displacement ≤2 mm) medial malleolus fractures compared with nonfixation after fibular stabilization.Design, Setting, and ParticipantsThis superiority, pragmatic, parallel, prospective randomized clinical trial was conducted from October 1, 2017, to August 31, 2021. A total of 154 adult participants (≥16 years) with a closed, unstable bimalleolar or trimalleolar ankle fracture requiring surgery at an academic major trauma center in the UK were assessed. Exclusion criteria included injuries with no medial-sided fracture, open fractures, neurovascular injury, and the inability to comply with follow-up. Data analysis was performed in July 2022 and confirmed in September 2023.InterventionsOnce the lateral (and where appropriate, posterior) malleolus had been fixed and satisfactory intraoperative reduction of the medial malleolus fracture was confirmed by the operating surgeon, participants were randomly allocated to fixation (n = 78) or nonfixation (n = 76) of the medial malleolus.Main Outcome and MeasureOlerud-Molander Ankle Score (OMAS) 1 year after randomization (range, 0-100 points, with 0 indicating worst possible outcome and 100 indicating best possible outcome).ResultsAmong 154 randomized participants (mean [SD] age, 56.5 [16.7] years; 119 [77%] female), 144 (94%) completed the trial. At 1 year, the median OMAS was 80.0 (IQR, 60.0-90.0) in the fixation group compared with 72.5 (IQR, 55.0-90.0) in the nonfixation group (P = .17). Complication rates were comparable. Significantly more patients in the nonfixation group developed a radiographic nonunion (20% vs 0%; P &amp;lt; .001), with 8 of 13 clinically asymptomatic; 1 patient required surgical reintervention for this. Fracture type and reduction quality appeared to influence fracture union and patient outcome.Conclusions and RelevanceIn this randomized clinical trial comparing internal fixation of well-reduced medial malleolus fractures with nonfixation, after fibular stabilization, fixation was not superior according to the primary outcome. However, 1 in 5 patients developed a radiographic nonunion after nonfixation, and although the reintervention rate to manage this was low, the future implications are unknown. These results support selective nonfixation of anatomically reduced medial malleolar fractures after fibular stabilization.Trial RegistrationClinicalTrials.gov Identifier: NCT03362229
Intra-Anterior Chamber Injection of Ranibizumab in Advanced Pediatric Vitreoretinal Diseases
Authors: Zhang Wenting , Liu Huanyu , Chen Yiye , Zhang Xuerui , Gu Victoria Y. , Xiao Haodong , Yang Yuan , Yin Jiawei , Peng Jie , Zhao Peiquan 
Published: January 2024

ImportanceAnti–vascular endothelial growth factor (VEGF) treatment through intravitreal or subretinal administrations has been proven effective for VEGF-driven pediatric vitreoretinal diseases but are not feasible for advanced cases, such as shallow traction retinal detachments or peripheral circumferential retinal detachments which adhere to the lens. Intra-anterior chamber injection (IAcI) of anti-VEGF may be a viable alternative in such cases but needs evaluation.ObjectiveTo investigate the effects and safety of IAcI of anti-VEGF to treat VEGF-driven pediatric vitreoretinal diseases.Design, Setting, and ParticipantsThis was a retrospective observational case series study conducted at Xinhua Hospital, affiliated with Shanghai Jiao Tong University School of Medicine in China. The study included 14 eyes of 13 children diagnosed with vitreoretinal disease exhibiting elevated vascular activity between January and August 2023.InterventionIAcI with ranibizumab.Main Outcomes and MeasuresRetinal vascular abnormalities, vitreous hemorrhage resolution, and complications 1 month and 3 months after injection.ResultsOf 13 patients included in this study, 12 were male. The mean age was 4.6 years (range, 1 month to 9 years). Six patients were diagnosed with familial exudative vitreoretinopathy, 4 with morning glory syndrome, 1 with retinopathy of prematurity, and 2 with chronic retinal detachments of unknown causes. At 1-month postoperative follow-up, vascular activity had decreased in 14 of 14 eyes. At 3-month follow-up, vascular activity had resolved in 7 of 14 eyes, persisted in 6 of 14 eyes, and reactivated in 1 of 14 eyes. On final observation, no complications were reported.Conclusions and RelevanceThese findings support the possibility of treatment using IAcI with ranibizumab to decrease retinal vascular abnormalities in familial exudative vitreoretinopathy or retinopathy of prematurity or related conditions, but further studies are needed to understand more precise benefits and risks. This approach might be considered in cases where intravitreal or subretinal injection are not feasible, recognizing the limitations of these findings and that longer-term outcomes still need to be monitored.
Olfaction and Mobility in Older Adults
Authors: Yuan Yaqun , Chamberlin Keran W. , Li Chenxi , Luo Zhehui , Simonsick Eleanor M. , Kucharska-Newton Anna , Chen Honglei 
Published: January 2024

ImportanceDecreased mobility is a hallmark of aging. Olfactory dysfunction is common in older adults and may be associated with declines in mobility.ObjectiveTo determine whether poor olfaction was associated with faster declines in mobility in older adults.Design, Setting, and ParticipantsThis cohort study included 2500 participants from the Health, Aging, and Body Composition Study. Participants completed the Brief Smell Identification Test during the year 3 clinical visit (1999-2000) and were followed for up to 7 years. A data analysis was conducted between January and July 2023.ExposuresOlfaction was defined as good (test score, 11-12), moderate (9-10), hyposmia (7-8), or anosmia (0-6).Main Outcomes and MeasuresMobility was measured using the 20-m usual and fast walking tests in clinical visit years 3 to 6, 8, and 10 and the 400-m fast walking test in years 4, 6, 8, and 10.ResultsThe primary analyses included 2500 participants (1292 women [51.7%]; 1208 men [48.3%]; 960 Black [38.4%] and 1540 White [61.6%] individuals; mean [SD] age, 75.6 [2.8] years). Multivariate-adjusted analyses showed that poor olfaction was associated with slower walking speed at baseline and a faster decline over time. Taking the 20-m usual walking test as an example, compared with participants with good olfaction, the speed at baseline was 0.027 (95% CI, 0-0.053) m/s slower for those with hyposmia and 0.034 (95% CI, 0.005-0.062) m/s slower for those with anosmia. Longitudinally, the annual decline was 0.004 (95% CI, 0.002-0.007) m/s/year faster for those with hyposmia and 0.01 (95% CI, 0.007-0.013) m/s/year faster for those with anosmia. Similar results were obtained for the 20-m and 400-m fast walking tests. Further, compared with participants with good olfaction, the odds of being unable to do the 400-m test were 2.02 (95% CI, 1.17-3.48) times higher for those with anosmia at the year 8 visit and 2.73 (95% CI, 1.40-5.35) times higher at year 10. Multiple sensitivity and subgroup analyses supported the robustness and generalizability of the findings.Conclusion and RelevanceThe results of this cohort study suggest that poor olfaction is associated with a faster decline in mobility in older adults. Future studies should investigate underlying mechanisms and potential health implications.