bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estrogen Induces Nitric Oxide Production via Activation of Constitutive Nitric Oxide Synthases in Human Neuroblastoma Cells
Authors: Xia Yun , Krukoff Teresa L. 
Published: July 2004

AbstractAlthough it is becoming increasingly evident that nitric oxide (NO) mediates some of estrogen’s actions in the brain, the effects of estrogen on NO production through NO synthases (NOS) in neuronal cells have not yet been identified. Here we assessed changes in NO production induced by 17β-estradiol (E2) in cells of neuronal origin using human SK-N-SH neuroblastoma cells, which we show express all three isoforms of NOS. Involvement of NOS isoforms in E2-induced NO production was examined using isoform-specific NOS inhibitors. E2 (10−10–10−6m) induced rapid increases in NO release and changes in endothelial NOS (eNOS) expression, which were blocked by ICI 182,780, an antagonist of estrogen receptors. Increased levels of NO release and NOS activity induced by E2 were blocked by N5-(1-Imino-3-butenyl)-l-ornithine, a neuronal NOS inhibitor, and N5-(1-Iminoethyl)-l-ornithine, an eNOS inhibitor, but not by 1400W, an inducible NOS inhibitor. These results demonstrate that E2-stimulated NO production occurs via estrogen receptor-mediated activation of the constitutive NOSs, neuronal NOS and eNOS. The E2-induced NO increase was abolished when extracellular Ca2+ was removed from the medium or after the addition of nifedipine, an L-type channel blocker, and was partially inhibited using 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester, an intracellular Ca2+ chelator. However, 1,2-bis(2-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid acetoxymethyl ester itself also caused an increase in NO release that was blocked by 1400W, suggesting that inducible NOS mediates this response. Together these data reveal that constitutive NOS activities are responsible for E2- induced NO production in neuroblastoma cells and that differential activation of NOS isoforms in these cells occurs in response to different treatments.
Developmental and Hormonally Regulated Messenger Ribonucleic Acid Expression of KiSS-1 and Its Putative Receptor, GPR54, in Rat Hypothalamus and Potent Luteinizing Hormone-Releasing Activity of KiSS-1 Peptide
Authors: Navarro V. M. , Castellano J. M. , Fernández-Fernández R. , Barreiro M. L. , Roa J. , Sanchez-Criado J. E. , Aguilar E. , Dieguez C. , Pinilla L. , Tena-Sempere M. 
Published: July 2004

Abstract
The gonadotropic axis is centrally controlled by a complex regulatory network of excitatory and inhibitory signals that is activated at puberty. Recently, loss of function mutations of the gene encoding G protein-coupled receptor 54 (GPR54), the putative receptor for the KiSS-1-derived peptide metastin, have been associated with lack of puberty onset and hypogonadotropic hypogonadism. Yet the pattern of expression and functional role of the KiSS-1/GPR54 system in the rat hypothalamus remain unexplored to date. In the present work, expression analyses of KiSS-1 and GPR54 genes were conducted in different physiological and experimental settings, and the effects of central administration of KiSS-1 peptide on LH release were assessed in vivo. Persistent expression of KiSS-1 and GPR54 mRNAs was detected in rat hypothalamus throughout postnatal development, with maximum expression levels at puberty in both male and female rats. Hypothalamic expression of KiSS-1 and GPR54 genes changed throughout the estrous cycle and was significantly increased after gonadectomy, a rise that was prevented by sex steroid replacement both in males and females. Moreover, hypothalamic expression of the KiSS-1 gene was sensitive to neonatal imprinting by estrogen. From a functional standpoint, intracerebroventricular administration of KiSS-1 peptide induced a dramatic increase in serum LH levels in prepubertal male and female rats as well as in adult animals. In conclusion, we provide novel evidence of the developmental and hormonally regulated expression of KiSS-1 and GPR54 mRNAs in rat hypothalamus and the ability of KiSS-1 peptide to potently stimulate LH secretion in vivo. Our current data support the contention that the hypothalamic KiSS-1/GPR54 system is a pivotal factor in central regulation of the gonadotropic axis at puberty and in adulthood.
Extracellular Signal-Regulated Kinases Are Involved in the Acute Activation of Steroidogenesis in Immature Rat Leydig Cells by Human Chorionic Gonadotropin
Authors: Martinelle N. , Holst M. , Söder O. , Svechnikov K. 
Published: July 2004

AbstractWe studied the involvement of the ERK cascade in human chorionic gonadotropin (hCG)-induced steroidogenesis by primary cultures of immature rat Leydig cells. Our findings indicate that protein kinase A and protein kinase C function as upstream kinases in connection with transduction of the signal from the gonadotropin receptor to the ERK cascade. These MAPKs enhance the stimulatory effects of hCG on the de novo synthesis of the steroidogenic acute regulatory protein and the activity of protein phosphatase 2A, which are associated with increased androgen production by the Leydig cell. Specific inhibition of ERK1/2 by Uo126 suppressed all of these cellular responses to hCG. In contrast, steroidogenesis from 22OHC (a cell-permeable form of cholesterol) is not inhibited by Uo126, suggesting that cholesterol delivery to mitochondria is being affected by this compound. We propose that the ERK cascade is an important part of the signal transduction pathway involved in the rapid hormonal responses of Leydig cells to trophic hormones. In hCG-activated Leydig cells, these MAPKs may play a role in controlling the biosynthesis of the steroidogenic acute regulatory protein as well as regulating protein phosphatase 2A activity, thereby governing cholesterol transport across the mitochondrial membrane.
Recent Developments in Studies of Electronic Excited States by Means of Electron Paramagnetic Resonance Spectroscopy
Authors: Yamauchi Seigo 
Published: July 2004

Abstract
New trends of electron paramagnetic resonance (EPR) are reviewed in studies of the electronic excited states conducted during this decade. The studies include EPR of excited triplet states in fluid solution and excited multiplet states in a triplet–radical pair system. Together with these new areas, advanced methods and techniques such as two dimensional pulsed EPR and high frequency high field EPR have been developed to analyze the new findings. In addition, time-resolved EPR with cw microwave has now become a general and very useful technique in time-domain experiments. Our recent works on porphyrins, phthalocyanines, and fullerenes are described in more detail.
Transport Properties and Effective Intermolecular Potentials for O2–O2, N2–N2, and O2–N2
Authors: Maghari Ali , Jalili Amir Hossein 
Published: July 2004

Abstract
Effective intermolecular potential-energy functions for O2–O2, N2–N2, and O2–N2 are obtained directly from the extended law of corresponding states for viscosity and experimental second virial coefficient data. The results are then used to obtain a best Morse–Spline–van der Waals (MSV) potential model. The present potential functions provide the best overall agreement for the available low-density gas-phase thermophysical data, i.e., second virial coefficient and transport properties. The effective intermolecular potential energies from the inversion of thermophysical data reproduce the viscosity, diffusion coefficient, and other transport coefficients within the experimental accuracy.
A Vibrational Analysis on Possible Peroxo Forms of Soluble Methane Monooxygenase
Authors: Yumura Takashi , Yoshizawa Kazunari 
Published: July 2004

Abstract
The vibrational structures for two possible peroxo intermediates of soluble methane monooxygenase (sMMO), in which O2 binds into the diiron(II) active site with end-on and side-on bridging modes, are analyzed from quantum chemical calculations at the B3LYP DFT level of theory. Dioxygen bridging modes should be controlled by carboxylate coordinations around the diiron active site. Two bridging carboxylato ligands are contained in the end-on peroxo complex, whereas one bridging carboxylato ligand is contained in the side-on peroxo complex. DFT calculations demonstrate that the end-on bridging mode into the diiron active site is energetically more stable than the side-on bridging mode. The end-on peroxo complex has a vibrational mode of O–O stretching at 909 cm−1, the isomer shift of which upon 18O2 substitution is 57 cm−1. The side-on peroxo complex exhibits a lower O–O stretching mode at 841 cm−1, and the isotope shift is 45 cm−1. The frequency of the O–O stretching mode and the 18O2 isotope shift are dependent on the dioxygen bridging modes in the active site of sMMO. The O–O stretching frequency in the end-on complex falls within the range measured in peroxo intermediates of other non-heme diiron enzymes and cis-μ-1,2 peroxo-bridged diiron(III) synthetic complexes. From the viewpoint of energetics and the vibrational frequencies, it is predicted that O2 should coordinate into the diiron active site of sMMO in an end-on cis-μ-1,2 fashion rather than a side-on fashion.
Photoinduced Electron-Transfer Processes of Fullerene (C60) with Amine Donors: Excited Triplet Route vs Excited Singlet Route
Authors: Sandanayaka Atula S D , Araki Yasuyuki , Luo Chuping , Fujitsuka Mamoru , Ito Osamu 
Published: July 2004

Abstract
Dynamic quenching processes of the excited states of C60 with amine donors have been studied by changing donor strength, donor concentration, and solvent polarity using steady-state and transient absorption and fluorescence spectroscopic techniques. Fluorescence quenching of C60 by amines was observed, which suggests a dynamic quenching process via the excited singlet state of C60 (1C60*) in polar and nonpolar solvents. In polar solvents, electron transfer via the excited triplet state of C60 (3C60*) producing radical ions (C60•− and amine•+) was observed by the nanosecond laser flash photolysis (ca. 6 ns laser pulse). When the donor concentrations are below 10–20 mmol dm−3, the concentrations of the radical ions increased with the donor concentrations. With further increase of the concentrations of the donors up to 100 mmol dm−3, on the other hand, the yields of the radical ions generated via 3C60* decreased. These findings indicate that dynamic quenching of 1C60* by amines increases with donor concentrations, resulting in a decrease of the intersystem crossing path to 3C60*; thus, the yields of the radical ions generated via 3C60* decreased even in the highly polar solvent. This implies that the radical ions generated by the dynamic quenching of 1C60* may be quite short-lived, even in polar solvents, compared with the radical ions via 3C60*.
Partitioning, Rotational Correlation, and Spin–Lattice Relaxation of Small Spin Probes in Dispersions of a Triglyceride Membrane
Authors: Nakagawa Kouichi 
Published: July 2004

Abstract
The partitioning, rotational correlation times (τR), and electron spin–lattice relaxation times (T1e) of various small spin probes in dispersions of a triglyceride membrane were investigated using CW-ESR (continuous wave-electron spin resonance) and SR (saturation recovery) spectroscopies. The partitioning of small spin probes, DTBN and TEMPO, in the aqueous and vesicle phases was determined by an ESR linewidth simulation. The results suggest that DTBN and TEMPO have a similar partitioning in the vesicle phase throughout the temperatures studied. The simulation results were quite different from those of conventional intensity analysis. In addition, the rotational correlation times of the vesicle phase for both probes varied from 1.2 × 10−10 to 4.9 × 10−10 s. The activation energy (Ea) calculated from the τR values in the phase was ∼29 [kJ/mol] for the probes. The thermal behavior based on the Ea value is that in between the 12-doxylstearic acid (12-DSA) and 16-DSA moieties of the membrane. The longer τR and shorter T1e (∼0.33 μs) values of DTBN in the vesicle phase were obtained, and could be attributed to the probe environment in the membrane. Thus, the present experimental evidence has provided a qualitative understanding of the probe dynamics as well as the membrane properties.
One-Step Electrochemical Cyanation Reaction of Pyrene in Polymer Microchannel-Electrode Chips
Authors: Ueno Kosei , Kitagawa Fumihiko , Kitamura Noboru 
Published: July 2004

Abstract
Polymer microchannel chips (100 μm width × 20 μm depth) integrated with electrodes were fabricated and applied to a one-step electrochemical cyanation reaction of pyrene (PyH). An acetonitrile solution of PyH containing tetrabutylammonium perchlorate and an aqueous NaCN solution were brought into the chip by pressure-driven flow, PyH was then oxidized at the working band electrode in the channel (1.5 V vs Ag). Under the optimum conditions, 1-cyanopyrene (PyCN) was produced very efficiently in the microchannel: 61% yield. It was also confirmed that, although 1,3-dicyanopyrene (Py(CN)2) was produced by bulk electrolysis (14% yield), its yield decreased to 4% in the microchip, with the PyCN/Py(CN)2 yield ratio being 2.9 or 15.3 for the bulk or chip experiments, respectively. In the case of an oil/water interfacial reaction system, a propylene carbonate solution of PyH and an aqueous NaCN solution were introduced to the channel, where an electrochemical cyanation reaction of PyH analogous to that mentioned above was conducted. The interfacial reaction in the microchip was successful and the yield of PyCN as the sole product was shown to be controlled by both the flow rate and the electrode position in the chip. In-situ space-resolved absorption spectroscopy of the electrochemical intermediate in the channel chip was also conducted to allow discussion of the reaction mechanisms.
Stability of FSM-16 in a Highly Moist and Aquatic Condition
Authors: Hashizume Hideo 
Published: July 2004

Abstract
The stability of a mesoporous material, FSM-16, against water vapor and water was investigated using an X-ray diffractometer with a relative humidity and temperature controlling unit. Under high relative humidity, the peaks for FSM-16 became smaller than the initial one from 60% of the relative humidity (RH) during an increase of the relative humidity from 10 to 95%, and the peak height was a minimum from 80 to 95% RH. However, the peaks for FSM-16 increased and returned back to the initial ones at 20% RH, while the relative humidity decreased. In soaked FSM-16 in water at 95% RH, the peaks for FSM-16 diminished owing to water. However, the peaks for FSM-16 appeared again, while water evaporated, and the peak heights were almost the same as the initial ones at 20% RH. However, the peak heights were about 25% lower than the initial ones after soaking FSM-16 in water for a long term. It might be supposed that the particles of FSM-16 on a sample holder were rearranged due to the pouring water, or that some of the mesopores for FSM-16 collapsed due to water.
μ-Acetato-di-μ-phenolato-metal(II)cobalt(II) (Metal = Fe, Co, Ni, Cu, Zn) Complexes with Low-Spin Co(II): Synthesis, Structures, and Magnetism
Authors: Matsumoto Kohta , Sekine Noboru , Arimura Keisuke , Ohba Masaaki , Sakiyama Hiroshi , Okawa Hisashi 
Published: July 2004

Abstract
The dinucleating macrocyclic ligand (L2;2)2−, prepared by the [1:1] cyclic condensation of N,N′-dimethyl-N,N′-ethylenedi(5-bromo-3-formyl-2-hydroxybenzylamine) and ethylenediamine, has dissimilar N(amine)2O2 and N(imine)2O2 metal-binding sites sharing two phenolic oxygen atoms. It has afforded μ-acetato-di-μ-phenolato-metal(II)cobalt(II) complexes (metal(II) = FeII, CoII, NiII, CuII, ZnII). X-ray crystallographic studies indicate that the MII is bound to the N(amine)2O2 site and has a square-pyramidal geometry with an acetate oxygen at the axial site. The CoII bound to the N(imine)2O2 site has a square-pyramidal geometry with an acetate oxygen at the apex or a distorted octahedral geometry with further coordination of a methanol molecule. The CoII in the N(imine)2O2 site is of low-spin and has one unpaired electron in its dz2 orbital. Magnetic studies indicate an antiferromagnetic interaction in the FeCo and CoCo complexes whereas a ferromagnetic interaction in the NiCo and CuCo complexes. The magnetic properties of the complexes are discussed in terms of the electronic structure of the MII ion and the dinuclear MCo core structure.
Preparation, Methylation, and Coupling Reaction of 1,2-Dithienyl-3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutenes
Authors: Toyota Kozo , Abe Keita , Horikawa Keiko , Yoshifuji Masaaki 
Published: July 2004

Abstract
Sterically protected 1,2-di(2-thienyl)- and 1,2-di(3-thienyl)-3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutenes were prepared and their properties were studied. When the dithienyldiphosphinidenecyclobutenes were allowed to react with butyllithium and then with iodomethane, the corresponding methylthienyl derivatives were obtained. The structure of (E,E)-1,2-bis(5-methyl-3-thienyl)-3,4-bis[(2,4,6-tri-t-butylphenyl)phosphinidene]cyclobutene was analyzed by X-ray crystallography. Lithiation of the dithienyldiphosphinidenecyclobutenes, followed by treatment with CuCl2, afforded the corresponding coupling products on the thiophene rings.
Synthesis, Isolation, and Characterization of Diels–Alder Adducts between 1,4-Dialkoxyanthracenes and Maleic Anhydride
Authors: Kitamura Chitoshi , Hasegawa Munehiro , Ishikawa Hiroshi , Fujimoto Jun , Ouchi Mikio , Yoneda Akio 
Published: July 2004

Abstract
In the Diels–Alder reaction of 1,4-dialkoxyanthracenes and maleic anhydride, which can afford syn- and anti-cycloadducts, the bridgehead methine proton of the cycloadducts has proved to be a useful probe for determining syn/anti selectivity, as supported by isolation of diastereomers, 1H NMR spectroscopy, and X-ray analysis. In the case of methoxy and propoxy substituents, a slight anti-preference was observed, on the other hand, the reaction of 1,4-bis(benzyloxy)anthracene gave a small syn-preference. Theoretical calculations of transition states of 1,4-dimethoxyanthracene and maleic anhydride showed no stereochemical preference. From UV–vis spectra, the formation of charge transfer complexes of anthracenes and maleic anhydride is possible.
Kinetics of Copper(I)-Catalyzed Dimerization and Hydration of Acetylene in Water
Authors: Tokita Yuichi , Okamoto Akio , Nishiwaki Kenichiro , Kobayashi Mineto , Nakamura Eiichi 
Published: July 2004

Abstract
The kinetics of the dimerization and hydration of acetylene in water with a copper(I) catalyst, a so-called Nieuwland catalyst, were investigated. The stationary state kinetics for both reactions could be described assuming that the rate-controlling step is a second-order reaction of an activated catalyst, [H···Cl–Cu–C2H], formed in the reaction mixture, with acetylene or water. The activation energies and activation entropies were 12.4 kcal·mol−1 and −33.3 cal·mol−1·K−1 for the acetylene dimerization, and 17.5 kcal·mol−1 and −34.2 cal·mol−1·K−1 for the acetylene hydration, respectively. The large negative values of activation entropy for these reactions may be accounted for by the role of water as a kind of cocatalyst.
The Correlation between Electrically Induced Stress and Mechanical Tensile Strength of Polypyrrole Actuators
Authors: Zama Tetsuji , Hara Susumu , Takashima Wataru , Kaneto Keiichi 
Published: July 2004

Abstract
Highly stretchable and powerful PPy film actuators, prepared electrochemically from a methyl benzoate solution of tetra-n-butylammonium tetrafluoroborate (TBABF4), showed a positive correlation between the electrochemical stress and the mechanical tensile strength. The more flexible CF3SO3−-doped PPy suits multi-wound or multi-folded actuators that can be used as artificial muscles.
Postoperative Radiotherapy and Survival in Oral Cavity Squamous Cell Carcinoma With Mandibulectomy
Authors: Harley Randall J. , Iheagwara Uzoma K. , Faraji Farhoud , Sridharan Shaum , Kubik Mark W. 
Published: February 2024

ImportanceOral cavity squamous cell carcinoma (SCC) tumors with mandibular invasion are upstaged to pT4a regardless of their size. Even small tumors with boney invasion, which would otherwise be classified as pT1-2, are recommended for the locally advanced treatment pathway to receive administration of postoperative radiotherapy (PORT).ObjectiveTo evaluate the association of PORT with overall survival according to tumor size among patients who received mandibulectomy for pT4aN0 oral cavity SCC.Design, Setting, and ParticipantsThis was a retrospective analysis using data from the US National Cancer Database from January 1, 2004, through December 31, 2019. All patients who received mandibulectomy for treatment-naive pT4aN0 oral cavity SCC with negative surgical margins were included. Data analyses were performed in January 2023 and finalized in July 2023.ExposurePORT vs no PORT.Main Outcomes and MeasuresEntropy balancing was used to balance covariate moments between treatment groups. Weighted multivariable Cox proportional hazards regression was used to measure the association of PORT with overall survival associated with tumor size.ResultsAmong 3268 patients with pT4aN0 oral cavity SCC (mean [SD] age, 65.9 [12.1] years; 2024 [61.9%] male and 1244 [38.1%] female), 1851 (56.6%) received PORT and 1417 (43.4%) did not receive PORT. On multivariable analysis was adjusted for age, insurance status, Charlson Comorbidity Index score, tumor site, tumor grade, tumor size, and PORT. Findings indicated that PORT was associated with improved overall survival and that this relative survival advantage trended upwards with increasing tumor size. That is, the larger the tumor, the greater the survival advantage associated with the use of PORT. For the 1068 patients with tumors greater than 4 cm, the adjusted hazard ratio (aHR) in favor of PORT was 0.63 (95% CI, 0.48-0.82); for the 1774 patients with tumors greater than 2 cm but less than or equal to 4 cm, the aHR was 0.76 (95% CI, 0.62-0.93); and for 426 patients with tumors less than 2 cm, the aHR was 0.81 (95% CI, 0.57-1.15).Conclusions and RelevanceIn this retrospective analysis of patients who received mandibulectomy for pT4aN0 oral cavity SCC, PORT was associated with improved overall survival, the benefit of which improved relatively with increasing tumor size. These findings suggest that tumor size should be considered in guidelines for PORT administration in this patient population.