bluuebunny/crossref_metadata_2025_split huggingface dataset:
Separation of Dissolved Aluminum in Neutral/Slightly Basic River Water by Cation-Exchange Chromatography with Fluorometric Detection of the Lumogallion–Aluminum Complex
Authors: Hara Hirokazu , Fujiwara Miyuki , Kamiyama Hiroko 
Published: January 2004

Abstract
The separation of dissolved aluminum in neutral/slightly basic river (Seta River) water was carried out using high-performance cation-exchange chromatography with a gradient elution of calcium ion in a dilute nitric acid solution (pH 4) and fluorometric detection of the lumogallion–aluminum complex. Although three peaks may appear, which correspond to species having a charge of less than +1, +2 and +3, only one major peak at the “3+” position appeared. From the sample pH and this result of separation, the main species of dissolved aluminum was concluded to be Al(OH)4−. In order to evaluate whether the elution was complete or not, the peak areas obtained with and without the cation-exchange column were compared. For an accurate evaluation of the elution peak, the residual solution of the solvent extraction with the 8-quinolinol/chloroform system was used. The elution of dissolved aluminum from the cation-exchange column was found to be incomplete (or not quantitative); i.e., the percentage of eluted aluminum was 79 and 70% for two Seta River water samples in October and January, respectively. The chemical form of the aluminum species which was adsorbed in the cation-exchange column is discussed.
Intermolecular Phenyl Ligand Transfer of Pt(II) and Pd(II) Complexes with Bidentate Ligand
Authors: Suzaki Yuji , Osakada Kohtaro 
Published: January 2004

Abstract
[PtPh2(dppe)] (dppe = 1,2-bis(diphenylphosphino)ethane) reacts with equimolar [PtCl2(cod)] (cod = 1,5-cyclooctadiene) to give a mixture of [PtPh2(cod)] (38%), [PtCl(Ph)(cod)] (53%) and [PtCl2(dppe)] (72%) via exchange of the phenyl and chloro ligands among the Pt complexes. The reaction is strongly inhibited by addition of Cl−. The intermolecular phenyl ligand transfer from Pd to Pt is observed in the reaction of [PdCl(Ph)(bpy)] (bpy = 2,2′-bipyridine) with [PtX2(cod)] (X = Cl, I), which produces [PtX(Ph)(cod)]. The reaction of [PdCl(Ph)(bpy)] with [PdCl2(cod)], giving [Pd2(μ-Cl)2{(4,5-η-κC1)-(C8H12Ph)}2], occurs much faster than a similar reaction of [PdCl(Ph)(bpy)] with [PtCl2(cod)]. [PtPh2(L2)] (L2 = cod, dppe) reacts with [PdCl2(cod)] in CH2Cl2 at room temperature to afford [Pd2(μ-Cl)2{(4,5-η-κC1)-(C8H12Ph)}2] via intermolecular phenyl ligand transfer from Pt to Pd and subsequent insertion of a C=C bond of cod into the Pd–Ph bond. Cationic Pd complexes [Pd(acetone)2(cod)]2+(BF4−)2 and [Pd(η3-C3H5)(acetone)2]+(BF4−) react with [PtPh2(cod)] to form biphenyl. All these results indicate that chloro complexes of Pd and Pt with cod ligand undergo the ligand exchange with the phenyl complexes of these metals.
Autocatalytic Nitration of Pyrene by Aerated Nitrogen Dioxide in Solution and Comparison with the Nitration on Silica Particles
Authors: Hasegawa Kiyoshi , Kaneko Hiroshi , Ogawa Tatsuya 
Published: January 2004

Abstract
The nitration mechanism of pyrene (PYH) by aerating NO2 in solution was studied by varying the factors (concentration of NO2, addition of HNO3 gas and H2O, 1-substituent on PYH, and solvent) affecting the nitration. Only 1-nitropyrene was formed. In acetonitrile, both the decrease in PYH and the increase in 1-nitropyrene depicted sigmoid curves, that is, their changes proceeded abruptly after an induction period, and finally approached to zero. The characteristic feature was reasonably explained by the facts that H+ dissociated from HNO3, accumulated by aerating NO2 into trace water-containing acetonitrile and released by the nitration, acted as an autocatalyst. The nitration proceeded electrophilically based on the 1-substituent effect of PYH, and accelerated with increasing polarity of the solvents. The nitration was studied kinetically and an ionic mechanism involving NO2+ as an electrophile was proposed. The nitration mechanism of PYH in acetonitrile was different from that in the adsorbed water on silica gel.
Synthesis of Allyl Acetals and Their Catalytic Claisen–Cope Rearrangement
Authors: Nakabayashi Kazuhiro , Ooho Masato , Niino Teppei , Kitamura Tsugio , Yamaji Teizo 
Published: January 2004

Abstract
We have synthesized various types of acetals using 3-methyl-3-butenal and 2-alkenyl, furfuryl, benzyl, p-substituted benzyl, and 2-pentynyl alcohols. These acetals have given corresponding aldehydes after an acid catalytic reaction. Trifluoroacetic acid (CF3COOH) was the best catalyst. The best yield attained was 79% when 3-methyl-3-butenal di(trans-2-pentenyl) acetal was used as a substrate. We also demonstrated that this reaction proceeded via a Claisen–Cope rearrangement.
A New Family of 2(3H)-Thiazolone Azines as Precursors to Air-Stable Radical Cations
Authors: Hammami Amer , Cavalié-Kosheiry Hicham , Armand Michel 
Published: January 2004

Abstract
A Novel 2(3H)-thiazolone azines family having RF substituents on the 4,4′-positions were efficiently prepared in good yield. The two-step synthesis involves the preparation of N,N′-dialkyl-1,2-hydrazinedicarbothioamides and their reaction with bromomethyl perflooroalkyl ketone, resulting in double ring closure. All the members prepared in this new family of compounds form stable radical cations, which enables them to be considered as ideal candidates for electrochemical tuning of light absorption as in electrochromic windows or displays and as redox indicators or mediators.
6-Nitro-2-benzothiazolyl α-Glucoside and α-Mannoside in β-Selective Glycosylations
Authors: Hashihayata Takashi , Mandai Hiroki , Mukaiyama Teruaki 
Published: January 2004

Abstract
Highly β-selective glucosylations of glycosyl acceptors having a primary hydroxy group with a 6-nitro-2-benzothiazolyl α-glucoside donor 3α proceeded smoothly in the presence of a catalytic amount of trifluoromethanesulfonic acid (TfOH) in CH2Cl2 at −78 °C to afford the corresponding glycosides in high yields. With the use of 3α, β-saccharides could be obtained more dominantly than other α-glucosyl donors such as thioform- and trichloroacet-imidates or fluoride in the glucosylation under the same conditions. Similarly, highly β-selective mannosylations of glycosyl acceptors with a 6-nitro-2-benzothiazolyl α-mannoside donor 18α were carried out smoothly in the presence of a catalytic amount of tetrakis(pentafluorophenyl)boric acid H[B(C6F5)4] to afford the corresponding disaccharides in good to high yields; 18α apparently behaved as a potent donor here for the construction of β-mannoside linkage. Interestingly, in situ anomerization from 18β to 18α was observed when β-mannosyl donor 18β was treated with a catalytic amount of H[B(C6F5)4] in CH2Cl2.
Synthesis of [2]- and [3]Rotaxanes by an End-Capping Approach Utilizing Urethane Formation
Authors: Furusho Yoshio , Sasabe Hisahiro , Natsui Daisuke , Murakawa Ken-ichi , Takata Toshikazu , Harada Toshiro 
Published: January 2004

Abstract
Several axle-shaped sec-ammonium salts having hydroxy groups at the terminal ends were allowed to react with 3,5-dimethylphenyl isocyanate in the presence of dibenzo-24-crown-8 ether (DB24C8) in CHCl3 by the catalysis of dibutyltin dilaurate to afford the corresponding [2]rotaxanes in good yields. Several Lewis acids other than dibutyltin dilaurate were effective for the end-capping. Although N,N-dimethylacetamide was not a suitable solvent, the use of chlorobenzene and nitromethane as solvents gave the [2]rotaxane in high yields. When a C2-chiral 26-membered crown ether, prepared from biphenyl-2,2′,6,6′-tetrol and l-tartaric acid, was employed instead of DB24C8, the corresponding optically active [2]rotaxane was isolated in 47% yield. The present method was successfully applied to the synthesis of [3]rotaxane by employing hexamethylene diisocyanate. Thus, end-capping by acid-catalyzed urethane formation from alcohol and isocyanate was demonstrated to be an effective protocol for the synthesis a variety of rotaxanes, based on the sec-ammonium salt/crown ether recognition motif.
Synthesis of 1,2,4-Trithiolanes from Thione S-Oxides and Lawesson Reagent at Room Temperature
Authors: Okuma Kentaro , Shigetomi Toshiyuki , Shibata Shinji , Shioji Kosei 
Published: January 2004

Abstract
The reaction of 2,2,4,4-tetramethyl-3-thioxocyclobutanone S-oxide with Lawesson reagent (L. R.) afforded the corresponding 1,2,4-trithiolane. Thiopivalophenone and thiopivalophenone S-oxides reacted with L. R. at rt to give the corresponding S-sulfide, which further reacted with thiones to afford the corresponding cis-1,2,4-trithiolanes.
pH Dependence of Interparticle Coupling for Gold Nanoparticle Assemblies Formation: Electrostatic Attraction and Hydrogen Bonding
Authors: Su Chia-Hao , Wu Pei-Lin , Yeh Chen-Sheng 
Published: January 2004

Abstract
With the addition of ω-sulfanylalkanoic or ω-alkyldisulfanylalkanoic acids to sodium-contained aqueous Au colloidal solutions, close-packed self-assembly occurred UV–vis, TEM, solid-state 13C NMR, and FT-IR spectra were employed to study the resulting aggregation arrays. The resulting two-dimensional Au assemblies exhibited interparticle coupling via both hydrogen bonding and electrostatic interactions at pH 6. Either acidic (pH 3) or base (pH 11) generated significant three-dimensional close-packed aggregates. It is suggested that electrostatic interactions might lead to the aggregates during the dry-up process in the preparation of TEM samples of the Au nanoparticles capped with COO− terminals at pH 11. For the acidic solutions (pH 3), coagulation was governed by hydrogen-bonding forces.
Time-Resolved Thermodynamic Properties of Intermediate Species during Photochemical Reactions
Authors: Terazima Masahide 
Published: January 2004

Abstract
Thermodynamics and kinetics are very large and important fields in science. However, experimental efforts to link these two fields have been very limited so far. For instance, although the themodynamical properties of transient species are essential for the knowledge of the nature and energetics of the reaction, such data have been very scarce. Kinetic study of a reaction from a view point of thermodynamic properties in the time domain should be very useful to detect a spectrally silent kinetic property. We have developed experimental methods to measure the time development of the thermodynamical properties of transient species without any assumption and without any temperature or pressure variations. Some of the results, in particular applications to reactions of biological proteins (photodissociation of the ligand of carboxymyoglobin, photo-reaction of Photoactive Yellow Protein (PYP) and octopus rhodopsin), are reviewed.
Recent Synthetic Advances of Tetrathiafulvalene-Based Organic Conductors
Authors: Otsubo Tetsuo , Takimiya Kazuo 
Published: January 2004

Abstract
The synthetic chemistry of tetrathiafulvalene (TTF)-type electron donors has been markedly promoted by introducing two key reactions, the one-pot preparation of 1,3-dichalcogenole-2-chalcogenones from terminal alkynes and the formation of heterocyclic rings via transalkylation on a chalcogen atom. In combination with a conventional trialkyl phosphite-promoted coupling reaction of 1,3-dichalcogenole-2-chalcogenones, the first reaction constitutes a ready access to the tetrachalcogenafulvalene skeleton. As a result, a number of previously inaccessible TTF-type electron donors were readily obtained. These included tetraselenafulvalene (TSF) derivatives, the selenium/sulfur or selenium/tellurium hybrid systems, dimeric TSFs linked with a single spacer group, and sophisticated stacked TSF phanes. The second reaction is very useful in constructing additional heterocyclic ring(s) on the tetrachalcogenafulvalene skeleton. A wide variety of five-, six-, and seven-membered heterocycle-fused TTF-type compounds were thus synthesized. These were systematically examined for superior electron donors of conductive molecular complexes. This study resulted in the discovery of two novel electron donors, methylenedithio-tetraselenafulvalene and methylenedithio-diselenadithiafulvalene, that form unique superconductors with exceptionally high conductivities at room temperature. The scopes and limitations of these synthetic reactions are described in connection with the recent research trends of TTF-based organic (super)conductors.
Dioxygen Reactivity of Copper(I) Complexes with Tetradentate Tripodal Ligands Having Aliphatic Nitrogen Donors: Synthesis, Structures, and Properties of Peroxo and Superoxo Complexes
Authors: Komiyama Kazuya , Furutachi Hideki , Nagatomo Shigenori , Hashimoto Akifumi , Hayashi Hideki , Fujinami Shuhei , Suzuki Masatatsu , Kitagawa Teizo 
Published: January 2004

Abstract
Oxygenation of copper(I) with tetradentate tripodal ligands (L) comprised of a tris(aminoethyl)amine (tren) skeleton having sterically bulky substituent(s) on the terminal nitrogens has been investigated, where L = tris(N-benzylaminoethyl)amine (LH,Bn), tris(N-benzyl-N-methylaminoethyl)amine (LMe,Bn), or tris(N,N-dimethylaminoethyl)amine (LMe,Me). All the copper(I) complexes reacted with dioxygen at low temperatures to produce superoxocopper(II) and/or trans-(μ-1,2-peroxo)-dicopper(II) complexes depending on the steric bulkiness of the terminal nitrogens and the reaction conditions. The reaction of a copper(I) complex [Cu(LH,Bn)]+ at −90 °C in acetone resulted in the formation of a superoxo complex [Cu(LH,Bn)(O2)]+ as a less stable species and a peroxo complex [{Cu(LH,Bn)}2(O2)]2+ as a stable species. The structures of [Cu(LH,Bn)]ClO4 and [{Cu(LH,Bn)}2(O2)](BPh4)2·8(CH3)2CO were determined by X-ray crystallography. [{Cu(LH,Bn)}2(O2)]2+ has a trans-(μ-1,2-peroxo)-dicopper(II) core with a trigonal bipyramidal structure. The O–O bond distance is 1.450(5) Å with an intermetallic Cu···Cu separation of 4.476(2) Å. The resonance Raman spectrum of [{Cu(LH,Bn)}2(O2)]2+ measured at −90 °C in acetone-d6 showed a broad ν(O–O) band at 837–834 cm−1 (788 cm−1 for an 18O labeled sample) and two ν(Cu–O) bands at 556 and 539 cm−1, suggesting the presence of two peroxo species in solution. [Cu(LMe,Bn)]+ also produced both superoxo and trans-μ-1,2-peroxo species, [Cu(LMe,Bn)(O2)]+ and [{Cu(LMe,Bn)}2(O2)]2+. At a lower concentration of [Cu(LMe,Bn)]+ (∼0.24 mM) and higher dioxygen concentration (P(O2) = ∼1 atm), the superoxo species is predominantly formed, whereas at a higher concentration of [Cu(LMe,Bn)]+ (∼1 mM) and lower dioxygen concentration (P(O2) = ∼0.02 atm) the formation of the peroxo species is observed. The resonance Raman spectrum of [Cu(LMe,Bn)(O2)]+ (∼1 mM) in acetone-d6 at ∼−95 °C exhibited a ν(O–O) band at 1120 cm−1 (1059 cm−1 for an 18O labeled sample) and that of [{Cu(LMe,Bn)}2(O2)]2+ (∼3 mM) in acetone-d6 at ∼−90 °C showed two ν(O–O) bands at 812 and 797 cm−1 (767 and 753 cm−1 for an 18O labeled sample), respectively. A similar observation was also made for [{Cu(LMe,Me)}2(O2)]2+. Relationships between the energies of the LMCT and d–d transitions and those of the ν(O–O) and ν(Cu–O) stretching vibrations and the steric constraints in the Cu(II)–(O22−)–Cu(II) core are discussed.
The Effect of NaClO4 Concentration on the Two-Step Electroreduction of Zn2+ Ions in the Presence of Tetramethylthiourea
Authors: Nieszporek Jolanta , Gugala Dorota , Sienko Dorota , Fekner Zygmunt , Saba Jadwiga 
Published: January 2004

Abstract
The dependence of the two-step reduction of Zn2+ ions on NaClO4 and TMTU concentration at the dropping mercury electrode was examined. The catalytic activity of TMTU is related to both electron transfer steps and decreases in the order: 1 M NaClO4 &gt; 0.5 M NaClO4 &gt; 0.1 M NaClO4. In each of the studied systems there was observed a much larger increase in the (kts2) values compared to the (kts1) values when the concentration of TMTU was increased. A linear relationship between the rate constant of the electroreduction of Zn2+ and the relative surface excess of TMTU indicates the formation of a bridge between Zn2+ and TMTU which facilitates the transfer of electrons across the inner layer.
Allergen immunotherapy in ENT: historical perspective
Authors: Kim D. S. , Drake-Lee A. B. 
Published: January 2004

The origins of immunology and allergy are founded upon the early 19th century microbiological studies of Jenner and Pasteur. It was discovered that the immune system could cause harm. The subspecialty of allergy began with the coining of the term by Von Pirquet in 1906 to describe disorders resulting from hyper-reaction to normally innocuous environmental agents.Understanding the scientific basis of the immune system and allergy allowed Noon and Freeman, and later Cooke, to develop allergen immunotherapy. Initially the technique was crude, but with the subsequent key discovery of IgE, more accurate methods of diagnosis (such as the radioallergosorbent test (RAST)) and treatment ensued. The efficacy of specific immunotherapy has been demonstrated by many double-blind trials culminating in the WHO position paper.DNA recombinant technology has provided detailed molecular understanding of allergic disorders, which has resulted in several novel methods of immunotherapy that are potentially safer and more effective. Use of recombinant allergens, T-cell peptides, DNA vaccination with CpG motifs or plasmid vectors and anti-IgE strategies with monoclonal antibodies are showing promise.
Infection, allergy and the hygiene hypothesis: historical perspective
Authors: Kim D. S. , Drake-Lee A. B. 
Published: January 2004

The ’hygiene hypothesis’ was popularized in the late 1980s to explain the high prevalence of atopic disordersin the developed countries. It links atopic disorders and the lack of early life infections. An association between the two is not novel and dates back to the beginnings of allergy, immunology and microbiology. Allergy and infection have always been closely related and the study ofone has often provided new insights into the pathobiology of the other. Early research into bacterial infections led to the discovery of the human immune system and the concept of allergy. An important relationship exists between parasite infections and the development of atopic disorders.This review traces the long and intimate historical relationship between infection and allergy.
Pre- and intra-operative staging of the neck in a developing world practice
Authors: de Waal Patrick J. , Fagan Johannes J. , Isaacs Sedick 
Published: January 2004

Most patients with squamous cancer of the head and neck treated at Groote Schuur Hospital are from a poor socio-economic background with a high prevalence of tuberculosis (TB), human immunodeficiency virus (HIV) and other infections that may cause cervical lymphadenopathy resulting in overstaging of the neck.A retrospective review of 186 patients requiring therapeutic and elective neck dissection was undertaken and the sensitivity and specificity of clinical and intra-operative staging of the neck determined.Results showed overall sensitivity of staging at 80.1 per cent. Specificity was 52.2 per cent. Staging of the N1, N2b and N2c necks had positive predictive values of 53.2, 65.8 and 68.2 per cent respectively. Occult nodal metastases were present in 32 per cent elective neck dissections (END)s. Specificity of intra-operative staging of the N0 neck was 33.3 per cent and sensitivity was 72.4 per cent.Conclusions were that our indications for elective neck dissection are appropriate. The high false positive rates for staging of the N1, N2b and N2c necks, necessitate a change in management strategy.
Chorda tympani neuroma masquerading as cholesteatoma
Authors: Hopkins C. , Chau H. , McGilligan J. A. 
Published: January 2004

Facial nerve neuromas occur throughout the course of the facial nerve and its branches, however lesions occurring on the chorda tympani branch are exceptionally rare.We present a case where the diagnosis was made intra-operatively; the patient was pre-operatively thought to have had a cholesteatoma.Total resection is the treatment of choice for these cases. Early diagnosis, aided by high resolution computed tomography (CT) scanning, will facilitate complete excision without damage to the facial nerve itself or the ossicular chain. The slow growing nature of the neuroma is likely to allow compensatory mechanisms to occur without the patient experiencing dysgeusia. As with any rarity the diagnosis can only be made with a high index of suspicion.
Heparin-Induced Hyponatremia
Authors: Norman N Elizabeth , Sneed Angela M , Brown Christine , Ellis Cecilia A , Minard Gayle , Brown Rex O 
Published: January 2004

OBJECTIVE To report a case of hyponatremia in a patient receiving systemic unfractionated heparin (UFH) therapy and parenteral nutrition. CASE SUMMARY A 70-year-old African American woman was started on parenteral nutrition for postoperative ileus following an elective surgical procedure. Three days later, she was diagnosed with a pulmonary embolism and intravenous UFH therapy was initiated. During the 7-day course of UFH therapy, the patient's serum sodium concentration steadily declined and urine sodium concentration progressively increased. Physical examination revealed no signs or symptoms of hypo- or hypervolemia. The patient's serum potassium concentration increased modestly, although significant hyperkalemia was not observed. After discontinuation of UFH, serum concentrations of both sodium and potassium returned to baseline levels. DISCUSSION Although heparin-induced hyperkalemia is well documented, cases associated with substantial hyponatremia have been reported less frequently. An objective causality assessment revealed that the adverse drug reaction was probable in this case. Hyponatremia and hyperkalemia result from the antagonism of aldosterone by UFH within the zona glomerulosa of the adrenal glands. CONCLUSION The use of UFH may result in significant hyponatremia as well as hyperkalemia. Reversal of these electrolyte disturbances occurs after discontinuation of heparin.
Stability of Lisinopril in Two Liquid Dosage Forms
Authors: Nahata Milap C , Morosco Richard S 
Published: January 2004

BACKGROUND Lisinopril is used in pediatric patients with hypertension. It is not commercially available as a liquid. Little is known about the stability of lisinopril in extemporaneously prepared liquid dosage forms. OBJECTIVE To determine the stability of lisinopril in 2 oral suspensions stored at 4 and 25 °C in plastic prescription bottles. METHODS Five bottles contained methylcellulose 1%:simple syrup NF (1:13) and the other 5 bottles had Ora Plus–Ora Sweet (1:1) at a lisinopril concentration of 1 mg/mL. Three samples were collected from each bottle at 0, 7, 14, 28, 42, 56, 70, and 91 days and analyzed by stability-indicating HPLC analytical method (n = 15). RESULTS At 4 °C, the mean ± SD concentration of lisinopril remained >95.1 ± 1.8% of the initial concentration in the methylcellulose formulation and 95.1 ± 3.2% of the initial concentration in the Ora Plus–Ora Sweet formulation throughout the 91-day study period. At 25 °C, the mean concentration of lisinopril remained >92.4 ± 2.2% of the initial concentration in the methylcellulose formulation for 8 weeks and 95.8 ± 2.3% of the initial concentration in the Ora Plus–Ora Sweet formulation throughout the 91-day study period. No changes in physical appearance in any samples were seen during this period CONCLUSION Lisinopril can be prepared in either of 2 liquid dosage forms and stored for at least 13 weeks under refrigeration and 8 weeks at room temperature.