bluuebunny/crossref_metadata_2025 huggingface dataset:
An apoptosis-differentiation program in human polymorphonuclear leukocytes facilitates resolution of inflammation
Authors: Kobayashi Scott D , Voyich Jovanka M , Somerville Greg A , Braughton Kevin R , Malech Harry L , Musser James M , DeLeo Frank R
Published: March 2003

Human polymorphonuclear leukocytes (PMNs) are an essential part of innate immunity and contribute significantly to inflammation. Although much is nderstood about the inflammatory response, the molecular basis for termination of inflammation in humans is largely undefined. We used human oligonucleotide microarrays to identify genes differentially regulated during the onset of apoptosis occurring after PMN phagocytosis. Genes encoding proteins that regulate cell metabolism and vesicle trafficking comprised 198 (98 genes induced, 100 genes repressed) of 867 differentially expressed genes. We discovered that complex cellular pathways involving glutathione and thioredoxin detoxification systems, heme catabolism, ubiquitin-proteasome degradation, purine nucleotide metabolism, and nuclear import were regulated at the level of gene expression during the initial stages of PMN apoptosis. Eleven genes encoding key regulators of glycolysis, the hexose monophosphate shunt, the glycerol-phosphate shuttle, and oxidative phosphorylation were induced. Increased levels of cellular reduced glutathione and γ-glutamyltransferase and glycolytic activity confirmed that several of these metabolic pathways were up-regulated. In contrast, seven genes encoding critical enzymes involved in fatty acid β-oxidation, which can generate toxic lipid peroxides, were down-regulated. Our results indicate that energy metabolism and oxidative stress-response pathways are gene-regulated during PMN apoptosis. We propose that changes in PMN gene expression leading to programmed cell death are part of an apoptosis-differentiation program, a final stage of transcriptionally regulated PMN maturation that is accelerated significantly by phagocytosis. These findings provide new insight into the molecular events that contribute to the resolution of inflammation in humans.
Control of the Magnetic and Optical Properties in Molecular Compounds by Electrochemical, Photochemical and Chemical Methods
Authors: Sato Osamu , Hayami Shinya , Einaga Yasuaki , Gu Zhong-Ze
Published: March 2003

The electrochemical, photochemical and chemical control of the magnetic properties in molecular compounds is described. The preparation of various thin films of CrCr and FeFe Prussian blue on a conducting electrode allowed us to control the magnetic properties by varying the oxidation state of the component metals. The magnetic properties of CrCr Prussian blue show that the critical temperature and coercive field can be drastically modified by electrochemical treatment. That is, the compound, CrII1.29CrIII0.14[CrIII(CN)6] has ferrimagnetic properties with Tc (critical temperature) = 240 K and Hc (coercive field) = 25 G, while the reduced form, KCrII1.29CrIII0.14[CrII(CN)6], has Tc = 100 K and Hc = 220 G. Similarly, it was found that the critical temperature of FeFe Prussian blue shifts continuously from paramagnetic to magnetic with Tc = 12 K. These changes can be expressed as K4FeII4[FeII(CN)6]3 (paramagnetic) ←→ FeIII4[FeII(CN)6]3 (ferromagnetic, Tc = 4.5 K) + 4 K+ + 4e− and FeIII4[FeII(CN)6]3 (ferromagnetic, Tc = 4.2 K) + 3Cl− − 3e−←→ FeIII4[FeIII(CN)6]3(Cl)3 (Tc = 12 K). Furthermore, we have discovered that the FeCo Prussian blue and Co valence tautomeric compounds exhibit photo-reversible magnetization effects. The photoinduced magnetization in FeCo Prussian blue is expressed as Na0.4CoII-HS0.3CoIII-LS[FeII(CN)6] (paramagnetic) ←→ Na0.4CoII-HS1.3[FeIII(CN)6] (ferrimagnetic, Tc = 26 K and Hc = 6000 G), where HS and LS denote high-spin and low-spin. An example of the photoinduced valence tautomeric behavior is expressed as [CoIII-LS(3,5-dbsq)(3,5-dbcat)(tmeda)] ←→ [CoII-HS(3,5-dbsq)2(tmeda)], where tmeda, 3,5-dbsq and 3,5-dbcat represent N,N,N′,N′-tetramethylethylenediamine, 3,5-di-tert-butyl-1,2-semiquinonate and 3,5-di-tert-butyl-1,2-catecholate, respectively. Additionally, we succeeded in tuning the phase transition temperature by varying the ligand field of the Co ions in the FeCo Prussian blue. Brief comments are also included regarding the first examples of light-induced excited spin state trapping observed in an FeIII complex, i.e. [FeIII-LS(pap)2]ClO4·H2O ←→ [FeIII-HS(pap)2]ClO4·H2O (pap = N-2-pyridylmethylidene-2-hydroxy-phenylaminato) and a photoinduced structural change observed in a CuII complex, [CuII(dieten)2](BF4)2 [dieten = bis(N,N -diethylethylenediamine)].
Syntheses, Structures, and Thermolyses of Three- and Four-Membered Heterocyclic Compounds Containing Highly Coordinate Main Group Elements
Authors: Kawashima Takayuki
Published: March 2003

Most titled compounds were synthesized by taking advantage of the Martin ligand. Their structures were determined by X-ray crystallography. Thermolyses of most of the four-membered ring compounds gave the corresponding Wittig-type products, while those of 1,2-oxasiletanides in the presence of proton source afforded the homo-Brook rearrangement products depending on bulkiness of the substituent at the 3-position. Pentacoordinate thiasiliranides were hydrolyzed to give the corresponding thiol, which seems to be formed via the initial cleavage of the Si–C bond followed by further hydrolysis of the corresponding thia-Brook rearrangement product. On the other hand, the most polarized bond of a pentacoordinate selenaphosphirane was found to be the P–Se bond, which was confirmed by its reaction with CF3SO3Me to give the corresponding 1-(methylseleno)alkylphosphonium triflate and by the solvent-dependent NMR study.
Synthesis and Biological Activities of Lipid A Analogs Possessing β-Glycosidic Linkage at 1-Position
Authors: Fukase Koichi , Ueno Atsushi , Fukase Yoshiyuki , Oikawa Masato , Suda Yasuo , Kusumoto Shoichi
Published: March 2003

New lipid A analogs having acidic groups β-glycosidically linked at the 1-position were synthesized in order to investigate the structural requirement for immunostimulating and endotoxic activity of lipid A. The β-(phosphonoxy)ethyl (PE) and carboxymethyl (CM) analogs of Escherichia coli type having six acyl groups and those of the biosynthetic precursor type having four acyl groups were synthesized via a divergent synthetic route. The E. coli type β-(phosphonoxy)ethyl analog, which was previously reported to be not endotoxic, showed strong immunostimulating activity comparable to the natural-type α-analog. The acidic functional groups are concluded to be essential but their strict spatial arrangement is not required for expression of the biological activity.
Raman Study of Hydration Effect on Conformational Equilibria of Haloacetones
Authors: Shiratori Yosuke , Nanba Yoshiaki , Kato Minoru , Taniguchi Yoshihiro
Published: March 2003

The conformational equilibria of chloroacetone and bromoacetone in various solvents were investigated using temperature and pressure-tuning Raman spectroscopy. Three conformational equilibria of gauche←→trans, gauche←→trans′ (trans conformer whose halogen atom forms hydrogen bonds with water), and trans←→trans′ were observed in water. Thermodynamic quantities between the conformers of both haloacetones in various solvents were evaluated from the temperature and pressure dependence of the Raman intensities of the C–X (X: Cl and Br) stretching modes. The effects of the substitution of halogen atoms were observed in the enthalpy and volume differences between the conformers in water. From the present results together with the previous results for fluoroacetone, a good correlation between the conformational thermodynamics for haloacetones in water and the polarizabilities of the halogen atoms was shown.
Construction of a Picosecond Time-Resolved IR Dip Spectrometer for Studying Structures and Dynamics of Solvated Clusters
Authors: Sakai Makoto , Ueda Tadashi , Yamanaka Takaya , Fujii Masaaki
Published: March 2003

We have constructed a picosecond time-resolved IR dip spectrometer having a frequency resolution of < 20 cm−1 and an instrument response time of 25 ps. In this system, the second harmonic of the idler wave from the OPA pumped at 800 nm and the remaining light from a regenerative amplifier (< 2.5 mJ/pulse) were differentially mixed in a KTA crystal to generate tunable high-power IR light (2750–4000 cm−1; > 60 μJ). The picosecond time-resolved IR dip spectra of phenol–(H2O)1 and carbazole–(H2O)1 are presented to demonstrate the capability of the constructed system. The spectral changes show clear vibrational structures of not only S0, but also S1 in the 2800–3800 cm−1 energy region. The system performance is also discussed.
Specific Complexation of Ursodeoxycholic Acid with Guest Compounds Induced by Co-grinding. II. Effect of Grinding Temperature on the Mechanochemical Complexation
Authors: Oguchi Toshio , Kazama Kazuo , Fukami Toshiro , Yonemochi Etsuo , Yamamoto Keiji
Published: March 2003

Ursodeoxycholic acid (UDCA) formed an inclusion complex with phenanthrene or with anthrone when being ground at an ambient temperature, while grinding at lower temperatures did not provide the complex but rather a mixture of amorphous UDCA and the guest compound crystals. Since heat treatment of the sample ground at low temperature did not provide the complex, it was concluded that the interplay of mechanochemical and thermal factors is responsible for the complexation of UDCA with the guest compound.
Schiff’s Bases Formed between Pyridoxal 5′-Phosphate and 4-Aminobutanoic Acid. Kinetic and Thermodynamic Study
Authors: Gorostidi Gerardo R Echevarría , Castellanos M Gabriela , Pérez Piedad Martín , Santos José G , Blanco Francisco García
Published: March 2003

The overall and individual kinetic constants of formation (k1 and k1i) and hydrolysis (k2, kOH and k2i) of the Schiff’s bases formed between pyridoxal 5′-phosphate (PLP) and 4-aminobutanoic acid (GABA) at 10, 20, 25, 30, and 37 °C, a variable pH and a constant ionic strength of 0.1 M (1 M = 1 mol dm−3) were determined. The formation of a Schiff’s base is an intramolecular acid-catalyzed process. The activation and thermodynamic parameters for the formation and hydrolysis of the Schiff’s bases were also determined. ΔH and ΔS for the individual processes were all found to be negative.
Molecular Modeling of the Solvent Structuring of DMSO around Cellulose Triacetate
Authors: Yu Isseki , Ueda Kazuyoshi , Nakayama Haruo
Published: March 2003

Molecular dynamics simulations of cellulose triacetate (CTA) were performed with explicit DMSO molecules in order to investigate the solvent structuring of DMSO around the CTA polymer. A hexamer unit of CTA was used as a model instead of polymer CTA. The molecular dynamics trajectory was started from a minimum conformation, which was found from an analysis of the adiabatic potential-energy surface obtained for glycosidic dihedral angles of φ and ψ. It showed that most of the time the trajectory stayed in their initial conformation in DMSO solvent. A distance analysis between the acetyl methyl residues of CTA showed that they are in good accordance with the NMR-NOESY data obtained by Tezuka.1 In order to elucidate the solvation structure of DMSO around the solute molecules, the site-specified radial distribution function, the orientation and the time courses of the DMSO movement were analyzed precisely. The results showed that some DMSO molecules strongly interact with CTA at specific sites, such as acetyl methyl residues and H1 ring protons. Moreover, it was found that those DMSO molecules frequently interact to CTA, not with one site, but with two or more sites simultaneously. These DMSO molecules would play an important role in the conformation of CTA in this solvent.
Conformation Preferences of 1,2-Dichlorotetranitroethane
Authors: Lam Yulin , Ma Ngai Ling , Huang Hsing Hua , Wang Li
Published: March 2003

The dipole moments of 1,2-dichlorotetranitroethane in carbon tetrachloride and benzene show that the compound favors the gauche conformer in solution-state. Experimentally derived values of the energy difference between the gauche and trans conformers and their population quotient are compared with values estimated by ab initio calculations. The agreement between experiment and theory is found to be excellent.
Deswelling Kinetics of a Porous Poly(N-isopropylacrylamide/methacrylic acid) Gel Prepared by Freeze-Drying
Authors: Kato Norihiro , Sakai Yasuzo , Kanazawa Atsushi
Published: March 2003

A linear correlation between the enthalpy of activation (ΔH≠) and the entropy of activation (ΔS≠) was observed for the deswelling process of porous poly(N-isopropylacrylamide/methacrylic acid) gels. The free energy of activation (ΔG≠) was nearly constant at +84 ± 2 kJ mol−1 irrespective of the methacrylic acid content and pH of the solutions.
Preconcentration of Trace Uranium from Natural Water with Solid-Phase Extraction
Authors: Shemirani Farzaneh , Abkenar Shiva Dehghan , Jamali Mohammad Reza
Published: March 2003

In the present study, an effective method was used for the preconcentration and determination of uranium(VI) by solid-phase extraction (SPE). For this purpose, a microcolumn of alumina modified with sodium dodecyl sulfate (SDS) and 1-(2-pyridylazo)-2-naphthol (PAN) was prepared for the preconcentration of trace uranyl(VI) from water samples. The uranium(VI) was completely eluted with 6.0 mol dm−3 HCl and determined by a spectrophotometric method with Arsenazo III. The SPE conditions were optimized by evaluating the effective factors such as pH, flow rate and masking agent. By the proposed method a preconcentration factor more than 150 was achieved. The average recovery of uranium(VI) was 99.8%. The relative standard deviation was 2.6% for ten replicate determinations of uranyl(VI) ion in a solution with a concentration of 50 ng cm−3. Some concomitant ions such as Cd2+, Ni2+, MoO42−, Cu2+, Th4+ and Ce3+, which interfere in the determination process of uranium(VI), were masked with EDTA in the aqueous phase during the extraction process. The proposed method was successfully used for the determination of uranium in natural water.
Syntheses and Structures of Mono- and Dinuclear Platinum Complexes of Pyrimidine-2-thiolate and Its 4-Methyl and 4,6-Dimethyl Derivatives
Authors: Asada Osamu , Umakoshi Keisuke , Tsuge Kiyoshi , Yabuuchi Shingo , Sasaki Yoichi , Onishi Masayoshi
Published: March 2003

The reaction of K2[PtCl4] with pyrimidine-2-thiol (pymSH) was reinvestigated. Among the possible four isomers, the major product was the cis isomer of [PtIII2Cl2(pymS)4] (1). The Pt(II) complex cis-[Pt2(pymS)4] (2) was prepared by the addition of NaOCH3 in the reaction mixture. The substitution of the axial Cl− ligands of 1 with Br− afforded the bromo complex [Pt2Br2(pymS)4] (3). While the reactions of K2[PtCl4] with 4-methylpyrimidine-2-thiol hydrochloride (4-mpymSH·HCl) in the presence of NaHCO3 gave a mixture of [Pt2Cl2(4-mpymS)4] (4) and trans-[Pt(4-mpymS)2] (5), the reaction with 4,6-dimethylpyrimidine-2-thiol (4,6-dmpymSH) gave only trans-[Pt(4,6-dmpymS)2] (7). The preference of bis-chelate mononuclear complexes for these ligands may be explained by considering steric hindrance between the ligands in the dimer. The oxidation of 5 by Ce(IV) afforded trans-dichloro Pt(IV) complex, [PtCl2(4-mpymS)2] (6). The crystal structures of 1, 3, 6 and 7 were determined. The redox properties of 1 and 3 are also discussed.
Hydrothermal Synthesis and Calorimetric Study of Blue Molybdenum Bronze, K0.28MoO3
Authors: Chin Kin , Eda Kazuo , Suzuki Takashi , Sotani Noriyuki
Published: March 2003

The hydrothermal heating of H0.28MoO3 in a KCl solution at 431 K led to the formation of a single phase of K0.28MoO3. Hydrated molybdenum bronze was formed as a mid-product during conversion from hydrogen molybdenum bronze to blue bronze. The formation enthalpy of K0.28MoO3 was determined by solution calorimetry to be ΔfH° (K0.28MoO3, s) = −840.2 kJ mol−1 at 298.15 K. The enthalpies of the transformation reaction from hydrogen bronze to hydrated bronze and of the formation reaction of blue K0.28MoO3 from hydrated bronze were calculated to be +33 kJ mol−1 and −48 kJ mol−1 at 298.15 K, respectively. The calculated enthalpies of the reactions were concordant with the suggested reaction mechanism for a transformation from hydrogen molybdenum bronze to potassium bronze.
Stereoselective Photoinduced Electron-Transfer Reaction between Zinc Myoglobin and New Chiral Quinolinium Ions
Authors: Tsukahara Keiichi , Ueda Rie
Published: March 2003

New chiral quinolinium derivatives, 1-[(S)- or (R)-(1-phenylethyl)carbamoylmethyl]-6-methoxyquinolinium hexafluorophosphate ([PMQ]PF6, 2) and 1-[(S)- or (R)-(1-phenylethyl)carbamoylmethyl]quinolinium hexafluorophosphate ([PQ]PF6, 3), were synthesized and characterized. A cyclic voltammetry in MeCN shows an irreversible redox behavior at −0.88 V and −0.85 V vs SCE (saturated calomel electrode) for 2 and 3, respectively. Fluorescence from the quinolinium moiety of 2 and 3 was observed at 455 nm and 440 nm, respectively. The fluorescence lifetime of 2 was longer than that of 3: τf = 30 ns (2) and 20 ns (3) in MeCN and τf = 26 ns (2) and 16 ns (3) in H2O). The excited triplet state of zinc-substituted myoglobin (3(ZnMb)*) was quenched by chiral [PMQ]+ and [PQ]+ ions; thereafter, the back electron-transfer (ET) reaction from a quinoline radical (PMQ• or PQ•) to a zinc myoglobin radical cation was detected. The stereoselectivity was observed for both ET quenching and back ET reactions; the (S)-isomers preferentially quench 3(ZnMb)* (kq(S)/kq(R) = 1.3 and 1.4 at 25 °C for [PMQ]+ and [PQ]+, respectively); in contrast, the (R)-isomers react faster than the (S)-isomers in the back ET reaction (kb(R)/kb(S) = 1.3 and 1.4 for PMQ• and PQ•, respectively). From a comparison of the rate constants with those for the previously reported systems we suggest that both the quenching and back reactions are controlled by ET, but not by conformational gating.
Degradation of Polychlorobiphenyls with Potassium Carbonate in Supercritical Water
Authors: Akiyama Fuminori
Published: March 2003

The degradation processes of 2,2′,5,5′-tetrachlorobiphenyl (4Cl-B) and 2,2′,4,4′,5,5′-hexachlorobiphenyl (6Cl-B) with potassium carbonate in supercritical water at 500 °C were studied. Hydrocarbons containing methane as major component were formed in the yield of around 15%. The main reaction product is considered to be inorganic salts, which do not show any NMR spectra and are easily decomposed by dilute acid.
The Layer Structure in Smectic A Phases and the Phase Transition Behavior for Cyano- and Nitrofuran Compounds
Authors: Tasaka Takeyasu , Okamoto Hiroaki , Morita Yuki , Abe Koichi , Kasatani Kazuo , Takenaka Shunsuke
Published: March 2003

The layer structure and phasetransition behavior of smectic A phases for 4-(4-alkoxyphenoxycarbonyl)phenyl 5-X-furan-2-carboxylates (X = CN, NO2) were examined by a small-angle X-ray diffraction method. The higher homologs of both compounds exhibit two kinds of smectic A (Sm A) phases and experience the Sm A-Sm A transition. One Sm A phase exhibited at a higher temperature region having a layer spacing of 1.5–1.9 times the calculated molecular length; and the layer spacing gradually increases with decreasing temperature. The other Sm A phase exhibited at a lower temperature region having a layer spacing of twice the calculated molecular length; also, the layer spacing is almost independent of the temperature. The Sm A–Sm A transition behavior is discussed.
Behavior of Naphthoyloxyl and Methoxynaphthoyloxyl Radicals Generated from the Photocleavage of Dinaphthoyl Peroxides and 1-(Naphthoyloxy)-2-pyridones
Authors: Najiwara Toshihiro , Hashimoto Ji-ichiro , Segawa Katsunori , Sakuragi Hirochika
Published: March 2003

1-Naphthoyloxyl and 2-naphthoyloxyl radicals were generated from photocleavage of dinaphthoyl peroxides and 1-(naphthoyloxy)-2-pyridones in acetonitrile. The difference in product distribution between the precursors is ascribed to the contribution of the two-bond cleavage in the peroxide decomposition in the singlet state. A series of methoxynaphthoyloxyl radicals were also generated from the corresponding (methoxynaphthoyloxy)pyridones and their behavior was compared with that of unsubstituted naphthoyloxyl radicals. The introduction of a methoxy group in the naphthalene ring stabilizes the naphthoyloxyl radicals to prevent their decarboxylation completely and reduces remarkably their reactivities in the addition to olefins and hydrogen-atom abstraction. The structure of the naphthoyloxyl radicals was discussed on the basis of their absorption spectra and MO calculations.
Difference between Enzymatic and Chemical N-methylations of Protoberberine-Type Alkaloid, Dependent on the Stereoisomer of (−)-N-methyl-7,8,13,13a-tetrahydroberberinium Salt
Authors: Kamigauchi Miyoko , Yoshida Mayumi , Noda Yuko , Nishijo Jujiro , In Yasuko , Tomoo Koji , Ohishi Hirofumi , Ishida Toshimasa
Published: March 2003

A possible relation between the stereostructure of (−)-(13aS)-tetrahydroberberine (1) and its enzymatic/chemical N-methylation, an important biosynthetic reaction to isoquinoline alkaloids in plants, was examined by CD spectroscopic, X-ray crystallographic, and energy calculation methods. The CD measurements indicated that 1 has two conformers (cis and trans) concerning the ring junction of the quinolizidine skeleton, and exist with a cis/trans ratio of about 1/4 in a diethyl ether : 2-methylbutane : ethanol (5 : 5 : 2) mixture. The dimensional/conformational difference between these cis and trans conformers was clarified by the X-ray crystal-structure analyses of two stereoisomers of N-methylated 1 (3 and 4). By using these structural parameters, the progress of N-methylation was simulated by energy profile calculations, suggesting that the cis and trans conformers are the major substrate for the enzymatic and chemical N-methylation reactions, respectively. Taking these results and the simulation of N-methylation of 1 by S-adenosyl-l-methionine at the binding pocket of N-methyltransferase into consideration, different pathways for chemical and enzymatic N-methylations of 1 have been proposed.
Multimetallic Complex Composed of Redox-Active Bridging Quinonediimine Ligand
Authors: Moriuchi Toshiyuki , Shen Xiuliang , Saito Kaori , Bandoh Seiji , Hirao Toshikazu
Published: March 2003

A π-conjugated quinonediimine ligand possessing two terminal redox-active ferrocenyl groups, N,N′-bis{(4′-ferrocenylcarboxamide)phenyl}-1,4-benzoquinonediimine (Lox), was synthesized. The quinonediimine ligand Lox was reduced to Lred composed of the phenylenediamine moiety on treatment with hydrazine hydrate. The reaction of Lox with the palladium(II) complex 1 bearing the N,N′-bis(2-phenylethyl)-2,6-pyridinedicarboxamide ligand afforded the multimetallic complex 2. Variable temperature 1H NMR studies of 2 indicated the existence of syn and anti isomers, in which the anti isomer is enthalpically more favorable than the syn isomer in CD2Cl2 by 0.9 kcal mol−1, but entropically less favorable by 2.6 cal mol−1 K−1 from the van’t Hoff plot. The redox function of the quinonediimine moiety is modulated by complexation with 1. The complex 2 showed three separate redox waves, which are assignable to the successive one-electron reduction of the quinonediimine moiety and oxidation of the two terminal ferrocenyl groups. Chemical reduction of 2 in CH2Cl2 with [Co(Cp)2] resulted in the appearance of ESR signals with weak 105Pd coupling centered around g = 2.004. The unpaired electron appears to locate mostly on the quinonediimine moiety with some delocalization onto the palladium center.
Micelle-Enhancing Effect on a Flavin-Photosensitized Reaction of Benzyl Alcohols in Aqueous Solution
Authors: Yasuda Masahide , Nakai Takuya , Kawahito Yasumasa , Shiragami Tsutomu
Published: March 2003

The tetra-O-acetylriboflavin (Fl)-photosensitized dehydrogenation of benzyl alcohols 1 proceeded more efficiently in aqueous solutions in the presence of sodium dodecyl sulfate (H2O/SDS) than acetonitrile solutions. The fluorescence quenching of Fl with 1 occurred efficiently in H2O/SDS. The apparent rate constants (kQ) for the fluorescence quenching were determined by Stern–Volmer plots. The plots of kQ vs the free-energy changes for the electron transfer from 1 to the excited singlet of Fl showed the Rehm–Weller-type correlation. However, plots for H2O/SDS were deviated from a curve calculated by the Rehm–Weller equation, although plots for MeCN were fitted to the calculated curve. The deviation in H2O/SDS is attributable to the incorporation of Fl and 1 into the hydrophobic domain of the SDS micelle, where the condensation, less-polar medium, and exteior negative charge operate favorably for efficient electron transfer.
Survey of Enhanced, Thermally Stable, and Soluble Second-Order Nonlinear Optical Azo Chromophores
Authors: Matsui Masaki , Suzuki Masayuki , Hayashi Masahiro , Funabiki Kazumasa , Ishigure Yoshinao , Doke Yasuo , Shiozaki Hisayoshi
Published: March 2003

A series of mono- and bisazo dyes were synthesized to obtain soluble, thermally stable, and enhanced second-order nonlinear optical chromophores (NLOphores). To prepare good sol-gel films, the most important factor was the solubility of NLOphores. Those azo NLOphores showing sufficient solubility were further classified into three groups: non-nitro-containing, nitro-containing, and fluorine-containing derivatives. Though non-nitro-containing NLOphores showed high solubility, their second-order nonlinearity was low. Nitro-containing NLOphores showed a rather high Td and a medium nonlinearity. Fluorine-containing NLOphores, especially perfluoroalkylsulfonyl derivatives, showed high nonlinearity and a rather low Td.
Synthesis and Properties of Monocyclic 5H-1,2-Oxathioles (Cyclic α,β-Unsaturated Sulfenic Acid Esters)
Authors: Ono Yutaka , Sugihara Yoshiaki , Ishii Akihiko , Nakayama Juzo
Published: March 2003

2,5,5-Trimethyl-3-hexyn-2-ol was successively treated with NaH and SCl2 in Et2O to provide 3-t-butyl-4-chloro-5,5-dimethyl-5H-1,2-oxathiole (1b), a class of α,β-unsaturated sulfenic acid ester, in 74% yield. Several S-unoxidized 5H-1,2-oxathioles were synthesized in similar ways. Analysis by cyclic voltammetry uncovered that the oxidation potentials of 1b, 3-(1-adamantyl)-4-chloro-5,5-dimethyl-5H-1,2-oxathiole (1c), and 4-chloro-5,5-dimethyl-3-phenyl-5H-1,2-oxathiole (1d) are +0.69, +0.68, and +0.78 V, respectively, and are lower than those of sulfides (thioanisole, +0.97 and dimethyl sulfide, +1.09 V), and also lower than that of an acyclic sulfenate ester (ethyl benzenesulfenate, +0.90 V). Thermolysis of 1c in boiling toluene furnished 2-(1-adamantyl)-3-chloro-4-methylthiophene in 81% yield.
Regio- and Stereo-Chemistry of Addition of Molecular Bromine to S-Oxidized Derivatives of 3,4-Di-t-butylthiophene: Exclusive 1,4-Cis-Additions
Authors: Nakayama Juzo , Furuya Tomohiro , Ishii Akihiko , Sakamoto Akira , Otani Takashi , Sugihara Yoshiaki
Published: March 2003

Bromine added to the 1-oxide, 1,1-dioxide, and sulfoximide derivatives of 3,4-di-t-butylthiophene exclusively in a 1,4-cis-addition mode. Thus, bromine added to 3,4-di-t-butylthiophene 1-oxide at room temperature in CH2Cl2 to give the 1,4-cis-adducts exclusively. The adducts are composed of two compounds in the ratio 57 : 43, where the major one is the anti-adduct respective to the S=O bond and the minor one is the syn-adduct. Addition of bromine to 3,4-di-t-butylthiophene 1,1-dioxide gave the 1,4-cis-adduct as the sole product. Addition of bromine to the N-tosyl substituted sulfoximide derivative of 3,4-di-t-butylthiophene afforded the single 1,4-cis-adduct in which two bromine atoms are anti to the N-tosyl group. Bromine added to the N-unsubstituted sulfoximide derivative of 3,4-di-t-butylthiophene to produce the 1,4-cis-addition products exclusively, which are a 67 : 33 mixture of the anti- and syn-adducts to the S=O bond.
Synthesis, Complexation Behaviors, and Crystal Structures of Azamacrocycles Having Tropon-2-yl Groups
Authors: Yamamoto Emi , Kubo Kanji , Mori Akira
Published: March 2003

Azamacrocycles 1–3, having one to three tropon-2-yl groups, were found to display unique absorption spectral changes in the presence of guest cations. Aza-15-crown-5 1, 1,7-diaza-12-crown-4 2a, 1,7-diaza-15-crown-5 2b, 1,10-diaza-18-crown-6 2c, and 1,5,9-triazacyclododecane 3 derivatives showed Ba2+, Zn2+, Ca2+, Ba2+, and Zn2+ selectivities, respectively. The crystal structures of free hosts 2a and 2c, the calcium thiocyanate complexes of 1 and 2c, the barium thiocyanate complex of 1, and the zinc thiocyanate complex of 2a were elucidated by X-ray analysis. The 2a·zinc and 2c·calcium thiocyanate complexes consist of an ion pair with a zinc tetrathiocyanate anion and a 2a·zinc cation and with a calcium hexathiocyanate anion and a 2c·H2O·calcium cation, respectively. The aminotropone moiety of 2a and 2c forms a conjugated 10-electron system. Complexation gave rise to deconjugation between the tropone ring and the nonbonding electron pair of the nitrogen atom to cause absorption spectral changes.
Deoxygenative Dimerization of Benzylic and Allylic Alcohols, and Their Ethers and Esters Using Lanthanum Metal and Chlorotrimethylsilane in the Presence of a Catalytic Amount of Iodine and Copper(I) Iodide
Authors: Nishino Toshiki , Nishiyama Yutaka , Sonoda Noboru
Published: March 2003

Benzylic and allylic alcohols were deoxygenatively dimerized by a treatment with lanthanum metal and chlorotrimethylsilane in the presence of a catalytic amount of iodine, giving the corresponding coupling products, alkanes, in moderate-to-good yields. This dimerization reaction was dramatically accelerated by the addition of a catalytic amount of copper(I) iodide. Similarly, ethers and esters were deoxygenatively dimerized by La/Me3SiCl/cat.I2/cat.CuI system in the presence of a catalytic amount of H2O.
Asymmetric Synthesis of the Main Pyridine Skeleton for a Macrobicyclic Antibiotic, Cyclothiazomycin
Authors: Endoh Nobuaki , Yonezawa Yasuchika , Shin Chung-gi
Published: March 2003

Stoichiometric asymmetric reduction of the ketone group of a 2-acetyl-3,6-disubstituted pyridine derivative with an oxazaborolidine and N-ethyl-N-isopropyl aniline-borane complex gave the corresponding (S)-lactone derivative 5 in 96% ee almost quantitatively. Hydrogenolytic cleavage of 5 gave the expected (S)-2-(1-hydroxyethyl)pyridine derivative.
Electrochemistry of Ruthenium Purple Confined in a Polymer Matrix: Voltammetry, Electrocatalysis for Hydrogen Evolution, and Electron-Transport Characteristics
Authors: Abe Toshiyuki , Kawai Noriaki , Tajiri Akio , Kaneko Masao
Published: March 2003

The synthesis of iron(III) ruthenocyanide (Ruthenium Purple, RP) in a Nafion (Nf) membrane was carried out. The visible-light absorption spectrum of the resulting RP exhibited an inter-valent charge-transfer band around 550–570 nm similar to that of neat RP, evidently showing that RP is formed in a polymer matrix. The voltammetric characteristics of the RP confined in the Nf matrix (Nf[RP]) were investigated compared with the neat RP. When Nf[RP] was used as an electrocatalyst to reduce H+, efficient H2 formation was found to originate from its molecular catalysis. In order to investigate the dominant factor that affects the overall kinetics in H+ reduction catalysis, the dependencies of both the catalytic activity (represented by the turnover number (TN) of a RP unit) and the diffusion coefficient of electron (Dapp) were studied as a function of the RP concentration in the matrix. The Dapp value decreased with increasing the concentration. The dependence of TN on the concentration was similar to that of Dapp, indicating that the overall kinetics is dominated by electron transport by RP.
Deactivation of a Cu/Al2O3 Catalyst in a N2O Decomposition Reaction
Authors: Tanaka Katsutoshi , Shimizu Atsushi , Fujimori Masami , Kodama Souhei , Sawai Shigeki
Published: March 2003

Dinitrogen oxide (nitrous oxide, N2O), a non-CO2 greenhouse gas, is produced as a by-product in the oxidation of cyclohexanone and cyclohexanol with nitric acid in adipic acid production plants. A Cu/Al2O3 catalyst has been used to decompose N2O to nitrogen and oxygen. We investigated the rate of deactivation of Cu/Al2O3 to establish an industrial abatement process for N2O. When Cu/Al2O3 catalyst containing 3 wt% of Cu was used, the apparent activation energy for the N2O decomposition reaction was estimated to be 167 kJ mol−1 at 746–853 K and 113 kJ mol−1 at 853–953 K. The former activation energy has been ascribed to an inhibition effect of oxygen. The rate constants of the N2O decomposition reaction have decreased with time. The decrease in the reaction-rates was analyzed by applying a first-order equation with respect to the rate constants. Simulation of the catalyst deactivation process has revealed that the Cu/Al2O3 catalyst is effective for at least for two years under the condition that 15 m3 of the catalyst is used for an adipic acid plant with a production capacity of 120 kt per year. Thus, we have concluded that the catalyst is suitable for use in industrial processes.
The Effect of MgO on the Enhancement of the Efficiency in Solid-State Dye Sensitized Photocells Fabricated with SnO2 and CuI
Authors: Perera Susira , Senadeera Rohan , Tennakone Kirthi , Ito Seigo , Kitamura Takayuki , Wada Yuji , Yanagida Shozo
Published: March 2003

Solid-state dye-sensitized photo cells were fabricated with nanocrystalline SnO2 covered with a thin layer of MgO as the anode and the hole conductor CuI as the cathode. While the cell fabricated with SnO2/Ruthenium bipyridyl dye/CuI delivered almost no photocurrent with very low photovoltage, the cell SnO2 (MgO)/Ruthenium bipyridyl dye/CuI delivered a short circuit photocurrent of ∼2.5 mA cm−2 with an open circuit voltage of ∼500 mV. Enhancement in the photocurrent and the voltages was found when the percentage of MgO to SnO2 was around 4 wt%. This is due to the formation of a thin energy barrier, which suppresses the recombination of photoelectrons.
Molecular Orientation in the Organized Molecular Films of Fluorinated Comb Polymers with Various Chain Lengths Studied by Soft X-ray Absorption Spectroscopy
Authors: Fujimori Atsuhiro , Araki Tohru , Nakahara Hiroo , Ito Eisuke , Hara Masahiko , Matsuie Noritaka , Ishii Hisao , Ouchi Yukio , Seki Kazuhiko
Published: March 2003

The molecular orientation in multilayer films of fluorinated comb polymers with various side-chain lengths can be characterized by near-edge X-ray absorption fine structures (NEXAFS) spectroscopy at the C K- and F K-edges. The spectra are found to change significantly with respect to the incidence angles of the soft X-rays and the number of layers in organized molecular films as well as chemical modifications such as fluorocarbon side-chain lengths, the atoms at the ω-position of the fluorocarbon side-chains, and α-methyl substituents. Analysis of these changes of the NEXAFS spectra provides useful information about the average molecular orientation in the X- and Z-types of mono- and multilayer films of the fluorinated comb polymers on solids.
Myringostapediopexy: surgical expectation
Authors: Dawes P. J. D.
Published: March 2003

Myringostapediopexy may occur as a result of incus erosion with medialization of the tympanic membrane and is recognized as often producing serviceable hearing. The technique may be used as part of tympanoplasty following either canal wall up or canal wall down surgery for chronic otitis media. The use of this type of reconstruction is influenced by the anatomy of the ear after disease excision. This review of the hearing levels associated with myringostapediopexy shows that there is a similar range of hearing level both for naturally formed as well as surgically fashioned myringostapediopexy. For both ’naturally formed’ and following canal wall up surgery about 80 per cent of patients will have an air-bone gap of 20 dB or less compared to 60 per cent of those who undergo canal wall down surgery.
Mucoepidermoid carcinoma arising from the eustachian tube and middle ear
Authors: Kim Young Ho , Chae Sung Won , Jung Hak Hyun
Published: March 2003

We report a case of mucoepidermoid carcinoma (MEC) originating from the eustachian tube and middle ear. A 31-year-old male who presented with otorrhoea and methicillin-resistant Staphylococcus aureus (MRSA) in the right ear was admitted to hospital due to cerebral infarction and deep vein thrombosis. After recovery, biopsies from a granulomatous mass found in the middle ear during operation for chro ic otitis media revealed intermediate-grade MEC and a nasopharyngeal mass identified after surgery also revealed the same result. He received combined radiation therapy and chemotherapy and no residual or recurrent tumour was detected after two years of follow-up.
A Female Patient With Recurrent Headache and Syncope
Authors: Mi Huai-Xue , Zheng Xiao-Zhou , Hongxin Li
Published: January 2024

This case report discusses a diagnosis of pulmonary arteriovenous fistulas in a female patient in her 30s who presented with a 5-year history of hypoxia, syncope, and headaches.
Clonal Hematopoiesis Risk Score and All-Cause and Cardiovascular Mortality in Older Adults
Authors: Saadatagah Seyedmohammad , Uddin Md Mesbah , Weeks Lachelle D. , Niroula Abhishek , Ru Meng , Takahashi Koichi , Gondek Lukasz , Yu Bing , Bick Alexander G. , Ebert Benjamin L. , Platz Elizabeth A. , Natarajan Pradeep , Ballantyne Christie M.
Published: January 2024

Importance

Clonal hematopoiesis (CH) with acquired pathogenic variants in myeloid leukemia driver genes is common in older adults but of unknown prognostic value.

Objective

To investigate the prevalence of CH and the utility of the CH risk score (CHRS) in estimating all-cause and disease-specific mortality in older adults with CH.

Design, Setting, and Participants

This population-based prospective cohort study involved community-dwelling older adults (aged 67-90 years) without hematologic malignant neoplasms (HMs) who were participants in the Atherosclerosis Risk in Communities Visit 5 at 4 US centers: Forsyth County, North Carolina; Jackson, Mississippi; Minneapolis, Minnesota; and Washington County, Maryland. Samples were collected from 2011 to 2013, sequencing was performed in 2022, and data analysis was completed in 2023.

Exposure

The exposure was a diagnosis of CH. CHRS scores (calculated using 8 demographic, complete blood cell count, and molecular factors) were used to categorize individuals with CH into low-risk (CHRS ≤9.5), intermediate-risk (CHRS >9.5 to <12.5), and high-risk (CHRS ≥12.5) groups.

Main Outcomes and Measures

The primary outcome was all-cause mortality, and secondary outcomes were HM mortality, cardiovascular disease mortality, and death from other causes.

Results

Among 3871 participants without a history of HM (mean [SD] age, 75.7 [5.2] years; 2264 [58.5%] female individuals; 895 [23.1%] Black individuals; 2976 White individuals [76.9%]), 938 (24.2%) had CH. According to the CHRS, 562 (59.9%) were low risk, 318 (33.9%) were intermediate risk, and 58 (6.2%) were high risk. During a median (IQR) follow-up of 7.13 (5.63-7.78) years, 570 participants without CH (19.4%) and 254 participants with CH (27.1%) died. Mortality by CHRS risk group was 128 deaths (22.8%) for low risk, 93 (29.2%) for intermediate risk, and 33 (56.9%) for high risk. By use of multivariable competing risk regression, subdistribution hazard ratios (sHRs) for all-cause mortality were 1.08 (95% CI, 0.89-1.31; P = .42) for low-risk CH, 1.12 (95% CI, 0.89-1.41; P = .31) for intermediate-risk CH, and 2.52 (95% CI, 1.72-3.70; P < .001) for high-risk CH compared with no CH. Among individuals in the high-risk CH group, the sHR of death from HM (6 deaths [10.3%]) was 25.58 (95% CI, 7.55-86.71; P < .001) and that of cardiovascular death (12 deaths [20.7%]) was 2.91 (95% CI, 1.55-5.47; P < .001).

Conclusions and Relevance

In this cohort study, the CHRS was associated with all-cause, HM-related, and cardiovascular disease mortality in older adults with CH and may be useful in shared decision-making to guide clinical management and identify appropriate candidates for clinical trials.
Optimal Surveillance Interval of Branch Duct Intraductal Papillary Mucinous Neoplasm of the Pancreas
Authors: Han Youngmin , Kwon Wooil , Lee Mirang , Jung Hye-Sol , Yun Won-Gun , Cho Young Jae , Chae Yoon Soo , Fernández-Del Castillo Carlos , Marchegiani Giovanni , Salvia Roberto , Goh Brian K. P. , Lee Woo Jin , Jang Jin-Young
Published: January 2024

Importance

Despite the increasing prevalence of intraductal papillary mucinous neoplasm (IPMN), data on the growth and malignant conversion rates based on long-term surveillance cohorts are limited. Many international guidelines recommend surveillance for benign lesions, but the optimal interval and duration are unclear.

Objective

To determine the optimal surveillance protocol for IPMN and propose which patients may be exempted from surveillance.

Design, Setting, and Participants

This large-scale, international cohort study examined data of 3825 patients with IPMN treated at 5 tertiary pancreatic centers. Included were patients with branch duct (BD) IPMN who underwent surveillance or surgery between January 1, 1988, and December 31, 2020. After a thorough review, 3656 patients were included in the analytic sample. Changes in cyst size, worrisome features or high-risk stigmata, and malignant conversion rates were assessed. Patients who underwent surveillance over 5 years were compared to suggest discontinuation of surveillance protocol. Clinical data collection began in January 1, 2021, and the mean (SD) follow-up duration was 84 (47.7) months. The data analysis was performed from May 2, 2022, through September 14, 2022.

Exposure

The patients with BD-IPMN were followed up based on International Association of Pancreatology guidelines. Patients with suspicious malignant neoplasms during surveillance underwent surgical resection.

Main Outcome and Measures

The main outcome of this study was the optimal follow-up interval and duration of BD-IPMN surveillance. The association among cyst size, growth rate, and progression was examined using descriptive statistics.

Results

Of the 3656 patients with BD-IPMN in the analytic sample (1973 [54.0%] female; mean [SD] age, 63.7 [10.2] years), 172 (4.7%) were confirmed to have malignant lesions through surgery. Considering cyst growth, the time to develop worrisome features, and malignant conversion, a 1.5-, 1-, and 0.5-year surveillance interval could be optimal for cysts smaller than 20 mm, 20 to 30 mm, and 30 mm, respectively, after initial short-term (6-month) follow-up. Patients with cysts smaller than 20 mm, no worrisome features, and no growth during 5-year surveillance did not show malignant conversion after 5 years of follow-up and had time to progression of greater than 10 years.

Conclusions

These findings suggest that BD-IPMN surveillance may depend on the size of the cyst and morphologic changes at the initial 6-month follow-up. For patients with small cysts (ie, <20 mm) with no morphologic changes during the initial 5-year surveillance period, surveillance may be discontinued for those unfit for surgery or who have a limited life expectancy of 10 years or less.
Effect of prescription isodose line on tissue sparing in linear accelerator‐based stereotactic radiosurgery treating multiple brain metastases using dynamic conformal arcs
Authors: Walter Yohan A. , Dugas Joseph P. , Broekhoven Bethany L. , Jacobs Troy D. , Han Muhong , Wang Chiachien J. , Wu Hsinshun T.
Published: January 2024

Purpose

Linear accelerator‐based stereotactic radiosurgery (SRS) has become a mainstay for simultaneous management of multiple intracranial targets. Recent improvements in treatment planning systems (TPS) have enabled treatment of multiple brain metastases using dynamic conformal arcs (DCA) and a single treatment isocenter. However, as the volume of healthy tissue receiving at least 12 Gy (V12) is linked to the probability of developing radionecrosis, balancing target coverage while minimizing V12 is a critical factor affecting SRS plan quality. Current TPS allow users to adjust various parameters influencing plan optimization. The purpose of this work is to quantify the effect of negative margins on V12 for cranial SRS plans managing multiple brain metastases.

Methods

Using the Brainlab Elements v3.0 TPS (Brainlab, Munich, Germany), we calculated V10, V12, V15, monitor units, and conformity index for seventeen SRS plans treating 2–10 metastases on our Elekta Versa HD (Elekta, Stockholm, Sweden) linear accelerator. We compared plans optimized using 70%‐90% prescription isodose lines (IDL) in 5% increments.

Results

Irrespective of the number of treated metastases, optimization at a lower prescription IDL reduced V10, V12, and V15 and increased MU compared to the 90% IDL (p < 0.01). However, comparing the 70% and 75% IDL optimizations, there was little difference in tissue sparing. The conformity index showed no consistent trends at different IDLs due to a significant spread in case data.

Conclusion

For our plans treating up to 10 metastases, diminishing returns for tissue sparing at IDLs below 80% paired with increasing treatment MU and dosimetric hot spot made optimization at lower IDLs less favorable. In our clinic, after consulting with a physician, it was determined that optimization at the 80% IDL achieved the best balance of V12, treatment MU, and maximum dose. Clinics implementing LINAC‐based SRS programs may consider using similar evaluations to develop their own clinical protocols.
Biomimetic Structural Design of Fabric for Low‐Cost, Scalable, and Highly Efficient Off‐Grid Solar‐Driven Water Purification
Authors: Tian Yankuan , Song Rui , Li Yiju , Zhu Ruishu , Yang Xin , Wu Dequn , Wang Xueli , Song Jianwei , Yu Jianyong , Gao Tingting , Li Faxue
Published: January 2024

Interfacial solar‐vapor generation (ISVG) is an emerging technology for water purification. However, high cost, low evaporation rate, clogging issues, and limited solar utilization under natural condictions greatly hinder its practical application. Herein, inspired by the aligned microstructure of dragonfly wings, a 3D microarray structure composed of vertically aligned hierarchical and hydrophilic carbon fibers (CFs) is constructed using a scalable fiber manufacturing technology. The microarray structure of the high‐thermal‐conductivity CFs with nanocapillaries contributes to the fast mass (steam and salt ions) and heat transfer as well as high omnidirectional light absorption. More importantly, due to the strong multiscale capillary effect, the formed 3D water evaporation surface containing abundant micro‐meniscuses and nanoscale thin water layers in the CFs arrays effectively reduces the evaporation enthalpy and creates more water/air interfaces, leading to the significant increasing evaporation rate. As a result, a high evaporation rate of 2.21 kg m−2 h−1 under one‐sun irradiation can be achieved. Moreover, the off‐grid water treatment device assembled with multiple 3D CFs‐based customized spherical evaporators can obtain a high pure water collection of 10.71 kg m−2 per day without salt accumulation under real environmental conditions. This work demonstrates a high‐efficiency, cost‐effective, and scalable strategy for high‐performance ISVG.