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Observations of the spontaneous growth of tin whiskers on tin-manganese alloy electrodeposits.

The spontaneous growth of tin whiskers on electrodeposited tin-manganese alloy coatings has been observed. This growth is distinct from any previously reported whisker growth on either pure tin or other tin-based alloy electrodeposits. It has an extremely short incubation period of a few hours only, followed by a spectacularly rapid and profuse growth. During the whole period of whisker growth, the tin-manganese electrodeposits were found to be in a tensile residual stress state. This rules out the commonly accepted explanation of a compressive stress as the driving force for tin whisker growth.

Journal Article↗

Comparison of the adhesive strength of a BIS-GMA cement to tin-plated and non-tin-plated alloys.

This study compared the tensile bond strengths of two base metal alloys and two noble metal alloys, tin-plated and non-tin-plated, with an adhesive resinous cement. Two tin platers were compared for their effectiveness in enhancing the composite resin-to-metal bond. Cylinders of the alloys were bonded end to end with the adhesive cement, thermocycled for 24 hours, stored in distilled water for 27 days, and tested for tensile bond strength. The mean bond strengths and mode of failure were recorded, and scanning electron micrographs were recorded for subjective evaluation. Significant differences were demonstrated between the non-tin-plated and the tin-plated noble alloys and base metal alloys.

Adhesives↗

Tin salts prevent the plasma cell response to metallic tin in Lewis rats.

Inoculation of metallic tin powder produced marked proliferation of plasma cells and Russell body cells in draining lymph nodes. Prior, but not concurrent, administration of a soluble tin salt in the drinking water prevented the plasma cell hyperplasia. Various Na, Zn, Ag, and Cu salts were not inhibitory. The inhibitory effect of tin salts was detected as long as 2 months after the pretreatment was stopped. If the plasma cell response to metallic tin were due to an immunologic reaction, then the inhibition by a soluble tin salt may be a form of immunologic tolerance.

Animals↗

The organ distribution of tin and the effect of tin on concentrations of several essential elements in rabbit.

The organ distribution and the effects of administration of tin, 5 mumol/kg/day, for 6 days on calcium, copper, iron, magnesium, phosphate, and zinc concentrations in plasma, erythrocytes, liver, kidney, and spleen of adult rabbits were studied. Kidney contained the highest concentration of tin, 15.0 +/- 1.64 micrograms/g wet weight (mean +/- S.D., n = 4). The concentrations of copper, phosphate, and magnesium increased significantly in the kidney, while magnesium concentration decreased in erythrocytes 1 day after the administration of tin for 6 consecutive days. A high correlation coefficient between magnesium and phosphate was observed in all organs tested. The correlation coefficients between P vs. Cu, P vs. Ca, and Mg vs. Ca in the liver were lowered during the period of tin administration, whereas those between P vs. Zn, Mg vs. Zn, and Cu vs. Zn in the kidney disappeared after tin administration was completed.

Animals↗

Tin, copper, iron and calcium metabolism of rats fed various dietary levels of inorganic tin and zinc.

Three studies were conducted to determine the effects of various dietary levels of tin (less than 1, approximately 100, approximately 200, approximately 500, approximately 2000 micrograms/g diet) and of zinc (approximately 15, approximately 30, approximately 52 micrograms/g diet) on the metabolism of tin, copper, iron and calcium by growing rats. The accumulation of tin in the kidneys and tibias of animals was proportional to dietary exposure. The concentration of tin in the bones of rats fed greater than 100 micrograms Sn/g diet was 5-fold and 20-fold greater than the levels found in kidney and liver, respectively. Rats fed greater than 500 micrograms Sn/g diet had plasma copper levels that were only 13% of control levels and had depressed copper levels in livers and kidneys. The activity of delta-aminolevulinic acid dehydratase in the erythrocytes of rats fed the highest level of tin was 55% of that found in control animals. The amounts, but not the concentrations, of calcium in the tibias of rats fed greater than 100 micrograms Sn/g diet were less than the levels in the bones of control animals. The moderate variations in dietary zinc levels did not affect significantly the levels of minerals in tissues.

Animals↗

Synthesis of tin and tin oxide nanoparticles of low size dispersity for application in gas sensing.

Nanocomposite core-shell particles that consist of a Sn0 core surrounded by a thin layer of tin oxides have been prepared by thermolysis of [(Sn(NMe2)2)2] in anisole that contains small, controlled amounts of water. The particles were characterized by means of electronic microscopies (TEM, HRTEM, SEM), X-ray diffraction (XRD) studies, photoelectron spectroscopy (XPS), and Mossbauer spectroscopy. The TEM micrographs show spherical nanoparticles, the size and size distribution of which depends on the initial experimental conditions of temperature, time, water concentration, and tin precursor concentration. Nanoparticles of 19 nm median size and displaying a narrow size distribution have been obtained with excellent yield in the optimized conditions. HRTEM, XPS, XRD and Mossbauer studies indicate the composite nature of the particles that consist of a well-crystallized tin beta core of approximately equals 11 nm covered with a layer of approximately equals 4 nm of amorphous tin dioxide and which also contain quadratic tin monoxide crystallites. The thermal oxidation of this nanocomposite yields well-crystallized nanoparticles of SnO2* without coalescence or size change. XRD patterns show that the powder consists of a mixture of two phases: the tetragonal cassiterite phase, which is the most abundant, and an orthorhombic phase. In agreement with the small SnO2 particle size, the relative intensity of the adsorbed dioxygen peak observed on the XPS spectrum is remarkable, when compared with that observed in the case of larger SnO2 particles. This is consistent with electrical conductivity measurements, which demonstrate that this material is highly sensitive to the presence of a reducing gas such as carbon monoxide.

Journal Article↗

Protein interactions with bivalent tin. 1. Hydrolysis and complexation of tin(II) ion with glycine.

The complexation between tin(II) ion and glycine was studied in 0.15 mol/dm3 NaCl medium at 310 K using potentiometric glass electrode titrations. In the pH range 1.1-4.5 and concentration range of the tin(II) between 0.2 and 5.0 mmol/dm3, with variable glycine-to-tin molar ratio up to 10:1, the experimental data were explained by the formation of the following complexes and their overall stability constants: log(beta +/- sigma): Sn(HGly)+, (12.78 +/- 0.08); Sn(Gly)+, (10.02 +/- 0.07); Sn(OH)Gly, (7.34 +/- 0.03), as well as the pure hydrolytic complex Sn4(OH)2+(6), whose stability constant was determined in separate experiments and found to be -4.30 +/- 0.08, under the same experimental conditions as for complexation study. The precipitate formed in tin(II)-glycine system at pH ca. 5.0 was characterized by chemical and TG analysis, I. R. spectra, X-ray powder diffraction, and electron scanning microscopy measurements. It has been shown that the precipitate has the composition Sn(OH)Gly and crystallizes in a tetragonal system with unit cell dimensions a = b = 1.584 nm, c = 0.597 nm. The mechanism of the complex formation in solution is discussed.

Cations, Divalent↗

Lead-tin mirror formation from mixtures of red lead and tin sulphide.

Mosaic gold, tin (IV) sulphide, is a yellow pigment which was known in antiquity but whose use was superseded by other more easily obtainable yellow pigments by the Renaissance. The identification of mosaic gold residues in a burnished golden mirror decoration on a XIIIth Century Spanish polychrome statue is important in that the first reference to the use of mosaic gold in the European literature dates from the XIVth Century, although the use of this material in China had been recorded some time before. In this paper, Raman spectroscopy, XRD and SEM are used in the analysis of the conditions required for the formation of golden mirrors using tin (IV) sulphide in admixture with dilead (II) lead (IV) tetroxide and mercury (II) sulphide. From these results, it is proposed that the major reactions are the reduction of Sn(IV) to Sn(0) with the accompanying oxidation of lead (II) oxide to lead (IV) oxide and the formation of lead (0) and lead (II) sulphide. From these results it was possible to explain the process of creation of the golden mirror from mosaic gold in the XIIIth Century.

Lead↗

[Effect of tin on rats. 1. Inverse voltammetric determination of tin in the presence of lead in biological material after extraction].

By means of inverse polarography, the authors determined tin selectively after double extraction with diethylammonium diethyl dithiocarbamate (DADDTC) in perchloric solution. The recovery rates were: in potatoes, 91.7 +/- 5.8%; in beef kidney, 85.0 +/- 22.7%; in beef liver 79.9 +/- 13.8%; and in milk, 69.8 +/- 11.4%. Possible interferences from other elements with the tin determination are discussed.

Animals↗

Investigation of silver salt metathesis: preparation of cationic germanium(II) and Tin(II) complexes, and silver adducts containing unsupported silver-germanium and silver-tin bonds.

Syntheses of halide derivatives of germanium(II) and tin(II) aminotroponiminate (ATI) complexes and their silver salt metathesis reactions have been investigated. The treatment of GeCl(2) x (1,4-dioxane), SnCl(2), or SnI(2) with [(n-Pr)(2)ATI]Li in a 1:1 molar ratio affords the corresponding germanium(II) or tin(II) halide complex [(n-Pr)(2)ATI]MX (where [(n-Pr)(2)ATI](-) = N-(n-propyl)-2-(n-propylamino)troponiminate; M = Ge or Sn; X = Cl or I). As usually expected, [(n-Pr)(2)ATI]GeCl and [(n-Pr)(2)ATI]SnCl undergo rapid metathesis with CF(3)SO(3)Ag, leading to trifluoromethanesulfonate salts, [[(n-Pr)(2)ATI]Ge][SO(3)CF(3)] and [[(n-Pr)(2)ATI]Sn][SO(3)CF(3)], and silver chloride. However, when the silver source [HB(3,5-(CF(3))(2)Pz)(3)]Ag(eta(2)-toluene) is used, rather than undergoing metathesis, very stable 1:1 adducts [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Ge(Cl)[(n-Pr)(2)ATI] and [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI] are formed (where [HB(3,5-(CF(3))(2)Pz)(3)](-) = hydrotris(3,5-bis(trifluoromethyl)pyrazolyl)borate). The use of the iodide derivative [(n-Pr)(2)ATI]SnI did not change the outcome either. All new compounds have been characterized by multinuclear NMR spectroscopy and X-ray crystallography. The Ag-Ge and Ag-Sn bond distances of [HB(3,5-(CF(3))(2)Pz)(3)]Ag<-- Ge(Cl)[(n-Pr)(2)ATI], [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(Cl)[(n-Pr)(2)ATI], and [HB(3,5-(CF(3))(2)Pz)(3)]Ag<--Sn(I)[(n-Pr)(2)ATI] are 2.4142(6), 2.5863(6), and 2.5880(10) A, respectively. A convenient route to [(n-Pr)(2)ATI]H is also reported.

Journal Article↗

A tin hydride designed to facilitate removal of tin species from products of stannane-mediated radical reactions.

The stannane 1, which is simple to prepare, behaves like the conventional reagents Bu3SnH and Ph3SnH in standard free radical reactions, but with the special characteristic that the tin-containing byproducts are easily and very largely removed by mild hydrolysis (LiOH-water-THF or TsOH-water-THF), which converts them into base-soluble (aqueous NaHCO3) materials. The performance of stannane 1 was evaluated for a range of radical reactions involving halides, selenides, Barton-McCombie deoxygenation, and enyne cyclization. In several cases the effectiveness of the workup procedure in removing tin species was monitored by 1H NMR.

Journal Article↗

Size-dependent detachment-limited decay kinetics of two-dimensional TiN islands on TiN(111).

In situ high-temperature (T(a)=1050-1250 K) scanning tunneling microscopy was used to determine the coarsening and decay kinetics of two-dimensional TiN adatom and vacancy islands on atomically smooth TiN(111) terraces. We report the first observation of an abrupt decrease in decay rates, irrespective of T(a), of adatom islands with areas less than a critical value of 1600 A(2). However, no decay rate transition was observed for vacancy islands. We attribute the size-dependent island decay behavior, which is consistent with detachment-limited kinetics, to anisotropic attachment and detachment barriers.

Journal Article↗

188Re radiopharmaceuticals for radiosynovectomy: evaluation and comparison of tin colloid, hydroxyapatite and tin-ferric hydroxide macroaggregates.

BACKGROUND: Radiosynovectomy is a therapy used to relieve pain and inflammation from rheumatoid arthritis and related diseases. In this study three 188Re particulate compounds were characterized according to their physico-chemical properties and their biological behavior in rabbits. The results were compared in order to establish which was the radiopharmaceutical that better fits the requirements of this kind of radiotherapy. METHODS: Three radiopharmaceutical formulations, tin colloid, hydroxyapatite particles (HA) and ferric hydroxide macroaggregates coated with tin colloid (FHMA), were physically characterized (number, volume and surface of the particles). For this purpose laser diffraction methodology was used. To evaluate cavity leakage of activity the following studies in New Zealand rabbits were performed: scintigraphic images for 48 hr after intraarticular injection of each radiopharmaceutical, biodistribution at 48 hr and urine samples collection during the first 24 hr post-radiopharmaceutical administration. RESULTS: Labeling procedures for 188Re-HA and 188Re-Sn-FHMA were labour intensive while 188Re-Sn was easily prepared. Furthermore, 188Re-Sn colloid offered the greatest surface area in the 2-10 microm range and was obtained with a radiochemical purity over 95%, while percentage of bound activity for 188Re-HA and 188Re-Sn-FHMA were 55% and 92% respectively. Stability was verified for the three radiopharmaceuticals for 24 hr. Scintigraphic studies and biodistribution in rabbits after intraarticular administration of the radiopharmaceuticals showed relevant activity only in the knee, this being over 90% of the residual activity in the whole body at 48 hr in every case. Renal elimination of 188Re-Sn colloid and 188Re-Sn-FHMA was detected by activity measurements in urine samples, during the first 12 hr post-radiopharmaceutical injection.The percentage of activity retained in the knee was 69.1% for 188Re-Sn colloid, 55.1% for 188Re-Sn-FHMA and 33.6% for 188Re-HA. CONCLUSION: The 188Re-Sn colloid was easy to prepare, minimum facilities were required, was stable for 24 hr and showed minimal leakage from the joint after intraarticular injection into the rabbit's knee. Furthermore, 188Re-Sn colloid has greater retention in the knee when it is compared with the other radiopharmaceuticals, so it could provide the best therapeutic effect/absorbed dose ratio for the patient.

Journal Article↗

Cytotoxic activity of bis-[di-n-butyl(4-aminosalicylato)tin] oxide, NSC: 628561, bis-[diphenyl(4-aminosalicylato)tin] oxide, NSC: 628562, and some related compounds, against a series of human tumour cell lines.

Bis[di-n-butyl (4-aminosalicylato)tin] oxide [NSC: 628561] (compound 1), bis [diphenyl(4-aminosalicylato)tin] oxide [NSC: 628562] (compound 2), and six other analogous compounds of the type [n-Bu2 (XYZ-C6H2COO)Sn]2O (compounds 3 to 8), were tested in vitro at the National Cancer Institute, Bethesda, Maryland, USA, for cytotoxic activity against a series of human cell lines. Compounds 1, 6 and 8 score globally satisfactorily since four of the five relevant sensitivity or selectivity parameters, DGI50, DTGI or DLC50, DH and MGDH, are statistically significant. Compounds 3 and 7 are less satisfactory because only three such parameters are statistically significant. For compound 2, only two of the parameters are significant.

Antineoplastic Agents↗

Photodynamic therapy of the ciliary body with tin ethyl etiopurpurin and tin octaethyl benzochlorin in pigmented rabbits.

BACKGROUND AND OBJECTIVES: The authors used a pigmented rabbit model to investigate two photosensitizers, tin ethyl etiopurpurin (SnET2) and tin octaethyl benzochlorin (BNZ 203), to determine their potential for creating ciliary body injuries during photodynamic therapy (PDT). MATERIALS AND METHODS: The biodistribution of SnET2 (n = 10) and BNZ 203 (n = 9) was studied by fluorescence microscopy using a low light detection system, based on charged-coupled device photography, with digital image processing at 1 and 24 hours after injection. PDT with SnET2 (n = 8; 664 +/- 7-nm light; 75 mW/cm2; 50 or 100 J/cm2; 1-mm spot size) and BNZ 203 (n = 6; 689 nm; 75 mW/cm2; 50 or 100 J/cm2; 1-mm spot size) was performed at 24 hours post-injection. The control subjects for SnET2 (n = 5) and BNZ 203 (n = 3) were given a maximal light dose (100 J/cm2). RESULTS: Both photosensitizers demonstrated an intravascular distribution at 1 hour that shifted to a ciliary body distribution at 24 hours (SnET2 much greater than BNZ 203). In addition, the SnET2 demonstrated suborgan localization to the nonpigmented ciliary body epithelium. Both photosensitizing agents were able to produce selective injury to the rabbit ciliary body (SnET2 much greater than BNZ 203), with evidence of a small component of thermal damage (SnET2 greater than BNZ 203). CONCLUSIONS: PDT with SnET2 or BNZ 203 can produce selective injury to the pigmented rabbit ciliary body. The nonpigmented ciliary body epithelium exhibits selective retention of SnET2. This finding warrants further investigation.

Animals↗

Photophysical properties of tin ethyl etiopurpurin I (SnET2) and tin octaethylbenzochlorin (SnOEBC) in solution and bound to albumin.

The photophysical characteristics of two second-generation PDT photosensitizers, tin ethyl etiopurpurin I (SnET2) and tin octaethylbenzochlorin (SnOEBC), have been measured in homogeneous solution and when bound to bovine serum albumin (BSA). The ground state and triplet state absorption spectra have been characterized, as have triplet lifetimes and quantum yields for intersystem crossing, singlet oxygen formation and photobleaching. In total, these parameters provide a complete set of data that can be used to quantitatively compare the photosensitizing efficiencies of these molecules. The photo-bleaching quantum yield of SnET2 is increased dramatically when it is bound to BSA, thus limiting the production of singlet oxygen at incident fluences above 1 J/cm2. In contrast, the quantum yield of photobleaching of SnOEBC is at least an order of magnitude lower than that of SnET2 under these conditions and does not significantly limit the photosensitization process for typical in vivo or in vitro fluences. This difference is expected to play a significant role in determining the relative photo-sensitizing ability of these compounds in vivo.

Animals↗