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Electrokinetic remediation of heavy metal-contaminated clay soils under neutral pH conditions is a challenging task due to the low water solubility of heavy metals. The objective of this study was to apply a biodegradable [S,S]-ethylenediamine disuccinic acid ([S,S]-EDDS) chelating agent to clay soils under neutral pH conditions to enhance the electrokinetic remediation efficiencies of cadmium (Cd) and lead (Pb). Bench-scale laboratory experiments were designed to investigate the influence of the [S,S]-EDDS concentration, applied voltage, and electrode materials on the remediation efficiencies. The soil pH was maintained near 7.0 for all of the experiments by adding HNO3 or NaOH in the electrode solutions. The experimental results showed that lead was not effectively removed from clay soils without the presence of [S,S]-EDDS due to its poor water solubility at neutral pH conditions. The remediation efficiencies were significantly enhanced by adding [S,S]-EDDS, indicating that the formation of the Pb–EDDS complexes increased the apparent water solubility of lead. The lead remediation efficiencies were enhanced by increasing either the applied voltage or the [S,S]-EDDS concentration. It was also determined that the electrode materials significantly influenced the remediation efficiency in the following order: platinum-coated titanium > iridium dioxide-coated titanium > graphite. Conversely, in case of cadmium, which has higher water solubility than lead, negatively charged Cd–EDDS complexes and positively charged cadmium ions moved in opposing directions, and as a result, cadmium accumulated at the center of the soil column. This study provided fundamental information on the design of an electrokinetic remediation system and will be useful to optimize the remediation conditions.

The read‐back signal degradation in seek motion with a pseudo‐contact head in a hard disk drive was studied. It was found by AES analysis that the pole tip surface of NiFe was covered with a decomposed layer of NiFe and carbon following seek motion. The read‐back signal degradation became larger with increasing thickness of the decomposed layer. An MFM study of the seek‐tested pole tip surface showed that the magnetic properties of the pole tip surface deteriorated by seek motion, and that the read‐back signal degradation increased with increase of deterioration of the magnetic properties of the pole tip surface. These results suggest that either the poor permeability of the decomposed layer on the pole tip surface and increase of spacing between the fresh pole tip surface under the decomposed layer and the disk surface decrease the flux flow from the disk magnetic layer into the pole tip, or that the decomposed layer on the gap short‐circuits the flux flow. It was found that the additive, cyclotriphosphazene, in a lubricant film, and a protective layer of carbon on a slider surface drastically reduced degradation.

A new system for the facile reduction of Met(O) in protected peptides (dimethylformamide-sulfur trioxide complex/iodide ion) was introduced. Met(O) in protected Met-enkephalins and protected leucosulfakinins were reduced to Met within 1h by this system, and the reducing ability of this new system seemed comparable to or greater than that of the formerly reported dimethylformamide-sulfur trioxide complex/ethanedithiol system. The methylsulfinylbenzyl protecting group of Tyr was also reduced to a methylthiobenzyl group by this system.

A novel approach for the synthesis of tyrosine sulphate [Tyr(SO3H)]-containing peptides was developed. In this approach, trifluoroacetic acid stable O-p-(methylsulphinyl)-benzyl group was used as a key protecting group for serine to achieve the selective sulphation of tyrosine.

A two dimensional computer simulation program was previously developed for the linear expansion of a bed packed with dispersed expansive particles in a matrix of non-expansive aggregate particles. For a qualitative comparison of the relationship between an apparent linear expansion of an experimental specimen and that of a model packed bed for a simulation, the bonding strength among particles was controlled as follows: (a) by changing the concentration of a lithium-silicate binder for an experimental specimen, and (b) by changing two parameters, i. e. Young's modulus and the geometrical moment of inertia for a bed packed with particles for simulation.

Dimethylformamide–sulphur trioxide (DMF–SO3) complex was found to be more suitable for tyrosine sulphation than pyridine–sulphur trioxide (Pyr–SO3) complex, the most commonly used sulphur trioxide complex for sulphation. The work-up after sulphation using DMF–SO3 was also easier than with Pyr–SO3. The usefulness of DMF–SO3 complex was demonstrated through the synthesis of two tyrosine sulphate [Tyr(SO3H)]-containing peptides, leucine-enkephalin sulphate and leucosulfakinin-II.

A new series of 1,2,3-trisubstituted-2-propen-1-one derivatives (9a-v, 10a-j, 13a-c, 14a-j) and 3,4-disubstituted-4-oxo-2-butenoic acids (6a-i, 7a-n) with azole compounds were synthesized. Inhibitory activities against rat passive cutaneous anaphylaxis (PCA) reaction and histamine release from rat mast cells were tested. The ester derivatives (7a-n, 14a-j) exhibited a more potent inhibitory activity against histamine release compared with alkylamine (9a-v), beta-hydroxyethoxy (10a-j) and carboxylic acid (6a-i, 13a-c) derivatives, but somewhat weaker in their anti-PCA activity. Structure-activity relationships were discussed.

A new system for the facile reduction of Met(O) in protected peptides (dimethylformamide-sulfur trioxide complex/iodide ion) was introduced. Met(O) in protected Met-enkephalins and protected leucosulfakinins were reduced to Met within 1h by this system, and the reducing ability of this new system seemed comparable to or greater than that of the formerly reported dimethylformamide-sulfur trioxide complex/ethanedithiol system. The methylsulfinylbenzyl protecting group of Tyr was also reduced to a methylthiobenzyl group by this system.

Human peptide YY (hPYY) was synthesized in a conventional manner by assembling six peptide fragments followed by deprotection with 1 M trimethylsilyl trifluoromethanesulfonate (TMSOTf)-thioanisole in trifluoroacetic acid (TFA). After purification by gel-filtration on Sephadex G-25, followed by reversed-phase high-performance liquid chromatography, a highly purified sample of synthetic hPYY was obtained. When administered in dogs, synthetic hPYY was as active as synthetic porcine PYY in terms of the effects on systemic arterial blood pressure, and splanchnic blood flow.

A new method for the effective reduction of methionine sulphoxide in protected peptides with sulphur trioxide and thiol has been developed. In practice, a combination of dimethylformamide–sulphur trioxide complex and ethane-1,2-dithiol was found effective, the presence of pyridine in the reaction medium being found necessary for the reduction to proceed. Methionine sulphoxide in two types of protected methionine–enkephalins was efficiently reduced to methionine by this reduction system at 20 °C in an hour. The (p-methylsulphinyl)benzyl protecting group was also reduced to (p-methylthio)benzyl simultaneously with the reduction of methionine sulphoxide. Subsequent deprotection afforded methionine–enkephalin of high purity in each case.

A convenient method for the synthesis of tyrosine sulphate [Tyr(SO3H)] containing peptides, using Fmoc–solid-phase strategy (Fmoc = fluoren-9-ylmethoxycarbonyl) for peptide-chain construction and O-p-(methylsulphinyl)benzyl serine for the selective sulphation of tyrosine, has been developed and cholecystokinin (CCK)-12 synthesized as a model peptide.

Thioanisole-trifluoromethanesulfonic acid and thioanisole-methanesulfonic acid systems were found to be useful as deblocking methods in the synthesis of a methionine-containing peptide, Met-enkephalin, without any side reaction.

In a conventional manner, two substance P analogs, [8-Tyr] and [5-Asn]-substance P, were synthesized. When contractility on isolated guinea-pig ileum was examined, [8-Tyr] and [5-Asn]-analogs exhibited the activities of 1.73 and 2.08 times higher than that of synthetic substance P respectively.

The chemical behavior of Nim-p-methoxybenzenesulfonylhistidine, His (MBS), was examined. This new Nim-protecting group was removable by HF or N-hydroxybenzotriazole, like the Nim-Tos group, but was more acid-stable than the Tos group with methanesulfonic acid or HBr. The Nim-MBS group was stable to treatment with trifluoroacetic acid in the presence of anisole, but was found to be cleaved smoothly by the same acid in the presence of dimethylsulfide at room temperature within an hour. The Nim-Tos group was also removable under similar conditions, but at a somewhat lower rate.

A detailed account of the synthesis of bovine neurotensin was presented. This tridecapeptide was synthesized in a conventional manner, after deprotecting three different protecting groups employed (Tos, Z and Bzl) by trifluoromethanesulphonic acid.

A newly isolated bovine brain pentapeptide, Thr-Ser-Lys-Tyr-Arg (neo-kyotorphin), which contains the Tyr-Arg (kyotorphin) unit at its carboxyl terminal portion, was synthesized by using the TFMSA-TFA-thioanisole deprotecting procedure. The synthetic peptide exhibited dosedependent analgesic activity in mice at a level approximately equal to that of Leu-enkephalin.

Human neuropeptide Y (hNPY) was synthesized in a conventional manner by assembling seven peptide fragments followed by reduction of the Met(O) residue with phenylthiotrimethylsilane and subsequent deprotection with 1 M trimethylsilyl trifluoromethanesulfonate (TMSOTf)-thioanisole in trifluoroacetic acid (TFA). Alternatively, deprotection was performed in a two-step manner; first, treatment with 1 M trimethylsilyl bromide-thioanisole in TFA, and then with 1 M TMSOTf-thioanisole in TFA. After purification by gel-filtration on Sephadex G-25, followed by reversed-phase high-performance liquid chromatography, a highly purified sample of synthetic hNPY was obtained in both cases. When administered in dogs, synthetic hNPY was as active as porcine NPY in terms of the effects on systemic arterial blood pressure, pancreatic blood flow, and superior mesentric artery (SMA) blood flow. Met(O)17-hNPY was found to be as active as the parent sample in these bioassays.

The 2,2,2-trichloroethoxycarbonyl (Troc) group attached at the Nin function of tryptophan by acylation with Troc-Cl in the presence of a catalytic amount of tetra-n-butylammonium hydrogensulfate can be quantitatively removed either by cadmium dust in acetic acid or under basic conditions, e.g., hydrazine hydrate and NaOH, but is resistant to strong acidic conditions.

Synthese en phase liquide avec deprotection par CF 3 -SO 3 H. Liberation de l'histidyl-1 par hydrolyse a 37°C. Autolyse du tetrapeptide N-terminal (His-Ser-Asp-Gly) et d'analogues

The reduction of trihalogenomethylnitroalcohols (1) and trihalogenomethylnitrodiols (2) as the compounds containing trihalogenomethyl radical of potential therapeutic interest were examined by different methods.It was confirmed that (1) had been reduced to trihalogenometylhydroxylaminoalcohols (3) by catalytic hydrogenation but one of the chlorine atoms in (1) had been removed by hydrogenolysis and had been reduced to dihalogenomethylaminoalcohols (4) and (3) by electrolytic reduction. Trihalogenomethylaminoalcohols (5) and trihalogenomethylaminodiols (6) were synthesized by the reduction of (1) and (2) with tin and hydrochloric acid.

The amino acid sequence of a newly isolated pentapeptide, neo-kyotorphin from bovine brain was synthetically verified to be Thr-Ser-Lys-Tyr-Arg corresponding to the C-terminal portion of hemoglobin α-chain. The synthetic neo-kyotorphin showed the dose-dependent analgesia in mice which was approximately equal to that of Leu-enkephalin.

The tridecapeptide corresponding to the amino acid sequence of rimorphin isolated from pituitary was synthesized using a trifluoroacetic acid-thioanisole deprotection system, which could deprotect o-2, 6-dichlorobenzyltyrosine, NG-2-mesitylsulfonylarginine, and Ne-benzyloxycarbonyllysine. Synthetic rimorphin exhibited an analgesic activity in the tail-pinch test.

The use of thioanisole as a scavenger was found to suppress a side reaction when the O-protecting groups of tyrosine were deblocked under the acidic conditions. This good result gives a promising outlook for the synthesis of tyrosine-containing peptides by solid-phase method.

Two enkephalin-containing peptides, peptide E and dynorphin(1-24), were synthesized by conventional solution methods employing a new Trp derivative, Nin-(2,4,6-triisopropylphenylsulfonyl)tryptophan [Trp(Tps)]. All protecting groups employed including the Tps group were removed by treatment with 1 M trifluoromethanesulfonic acid (TFMSA)-thioanisole in trifluoroacetic acid (TFA) at the final steps of these syntheses. Subsequent purifications by Sephadex G-25 chromatography, CM-Biogel A ion exchange chromatography, and reversed-phase high-performance liquid chromatography afforded highly purified samples. Both synthetic peptide E and dynorphin(1-24) exhibited high in vitro opioid activity. The usefulness of this new tryptophan derivative for practical peptide synthesis was established through these syntheses of complex Trp-containing peptides.

The heptatriacontapeptide amide corresponding to the entire amino acid sequence of human calcitonin gene-related peptide (hCGRP) was synthesized by assembling seven peptide fragments in solution, followed by deprotection with 1 M trifluoromethanesulfonic acid-thioanisole in trifluoroacetic acid and subsequent air-oxidation to establish the disulfide bridge. The S-1-adamantyl group of the Cys residue was removed in two ways; one was by treatment with the above acid, together with the other protecting groups employed, and the other was selectively by treatment with(CF3COO)3Tl. The synthetic peptide produced a significant increase of cyclic adenosine monophosphate in calvaria and brain of a newborn rat, but suppressed 45Ca-release from mouse calvaria stimulated by parathyroid hormone.

Five heptapeptide amides related to the C-terminal portion of tachykinins and two heptapeptide amides related to the C-terminal portion of bombesin-like peptides were synthesized and the smooth muscle contractile activity of these peptides was compared with that of the C-terminal heptapeptide of substance P by taking synthetic substance P as a standard.

A detailed account of the synthesis of bovine neurotensin was presented. This tridecapeptide was synthesized in a conventional manner, after deprotecting three different protecting groups employed (Tos, Z and Bzl) by trifluoromethanesulphonic acid.

The hexadecapeptide corresponding to positions 1 to 16 of porcine motilin was synthesized in a conventional manner. The synthetic peptide exhibited the activity of 3% of that of the synthetic motilin, when tested using rabbit duodenal muscle in vitro.