Independent isomeric-yield ratio of 89m,gNb from 93Nb(γ, 4n), natZr(p,xn), and 89Y(α, 4n) reactions

The independent isomeric-yield ratios of ^89m,gNb for the ⁹³Nb(γ, 4n) ^89m,gNb reaction with bremsstrahlung energies of 45-, 50-, 55-, 60-, and 70-MeV were measured by the activation and the off-line γ-ray spectrometric technique at 100 MeV electron linac of the Pohang accelerator laboratory. The isomeric-yield ratios of ^89m,gNb for the ^natZr(p, xn) ^89m,gNb and the ⁸⁹Y(α, 4n) ^89m,gNb reactions were measured by using a stacked-foil activation technique with the proton energies of 19–45 MeV and alpha energies of 38.9-, 40.5-, and 42.5-MeV at the MC-50 cyclotron of Korea Institute of Radiological and Medical Sciences. The measured isomeric-yield ratio of ^89m,gNb from the ⁹³Nb(γ, 4n), ^natZr(p, xn), and ⁸⁹Y(α, 4n) reactions were compared with the similar literature data in the ⁸⁹Y(³He, 3n) reaction. It was found that the isomeric yield ratio of ^89m,gNb increases with projectile energy, which indicate the effect of excitation energy. However, for the similar compound nucleus with the same excitation energy, the isomeric-yield ratios of ^89m,gNb in the ⁸⁹Y(α, 4n) and ⁸⁹Y(³He, 3n) reactions are higher than those in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions, which indicates the role of input angular momentum. The isomeric-yield ratios of ^89m,gNb in the ⁹³Nb(γ, 4n), ^natZr(p, xn), ⁸⁹Y(α, 4n), and ⁸⁹Y(³He, 3n) reactions were also calculated theoretically using computer code TALYS 1.4. The theoretical isomeric-yield ratios of ^89m,gNb from four reactions increase with excitation energy. However, the theoretical value are significantly higher than the experimental data in the ⁹³Nb(γ, 4n) and ^natZr(p, xn) reactions but slightly lower or comparable in the ⁸⁹Y(α, 4n) rand ⁸⁹Y(³He, 3n) reactions.     

Radiostrontium separation from sodium molybdate solution and its measurement using LSA: an application to radiopharmaceutical analysis

Technetium (^99mTc), a decay product of molybdenum (⁹⁹Mo), is employed as radioisotope in nuclear medicine. Several practical devices known as generators are commercially available which enable the user to separate the daughter from the parent radionuclide. The present study is focused on quality control of chromatographic technetium generator. A properly constructed generator should comply with international requirements of radionuclide purity of ⁹⁰Sr/⁹⁹Mo ≤ 6 × 10^?8 and ⁸⁹Sr/⁹⁹Mo ≤ 6 × 10^?7. For this purpose an analytical method was optimized to quantify radiostrontium (⁸⁹Sr and ⁹⁰Sr) in sodium molybdate [Na ₂ ⁹⁹ MoO₄] solution, a fission product used for ⁹⁹Mo/^99mTc generators. Dowex 1 × 8 and alumina were used in sequence followed by tributyl phosphate extraction for radiostrontium separation. Cerenkov measurement of ⁸⁹Sr and ⁹⁰Sr (through its descendent ⁹⁰Y) was performed using Perkin Elmer Tricarb LSA 3170 with detection efficiency of 42 and 14 %, respectively. Since efficiency of Cerenkov counting is sensitive to presence of color, spectral index of sample was used to correct the counting efficiency. The chemical recovery for strontium was 22 % and for yttrium was 80 % as determined by inductively coupled plasma optical emission spectrometry. Lower limit of detection was found to be 6.3 and 14.4 Bq L^?1 for ⁹⁰Sr and ⁸⁹Sr, respectively with 60 min counting time. Hence method can be applied successfully to analyze ^89,90Sr in fission molybdenum used as radiopharmaceutical with a relative error of <10 %.     

An assessment of the liquid–gas partitioning behavior of major wastewater odorants using two comparative experimental approaches: liquid sample-based vaporization vs. impinger-based dynamic headspace extraction into sorbent tubes

The gas–liquid partitioning behavior of major odorants (acetic acid, propionic acid, isobutyric acid, n-butyric acid, i-valeric acid, n-valeric acid, hexanoic acid, phenol, p-cresol, indole, skatole, and toluene (as a reference)) commonly found in microbially digested wastewaters was investigated by two experimental approaches. Firstly, a simple vaporization method was applied to measure the target odorants dissolved in liquid samples with the aid of sorbent tube/thermal desorption/gas chromatography/mass spectrometry. As an alternative method, an impinger-based dynamic headspace sampling method was also explored to measure the partitioning of target odorants between the gas and liquid phases with the same detection system. The relative extraction efficiency (in percent) of the odorants by dynamic headspace sampling was estimated against the calibration results derived by the vaporization method. Finally, the concentrations of the major odorants in real digested wastewater samples were also analyzed using both analytical approaches. Through a parallel application of the two experimental methods, we intended to develop an experimental approach to be able to assess the liquid-to-gas phase partitioning behavior of major odorants in a complex wastewater system. The relative sensitivity of the two methods expressed in terms of response factor ratios (RF_vap/RF_imp) of liquid standard calibration between vaporization and impinger-based calibrations varied widely from 981 (skatole) to 6,022 (acetic acid). Comparison of this relative sensitivity thus highlights the rather low extraction efficiency of the highly soluble and more acidic odorants from wastewater samples in dynamic headspace sampling.     

Characterization of poly(2-vinylpyridine)-block-poly(methyl methacrylate) copolymers and blends of their homopolymers by liquid chromatography at critical conditions

Poly(2-vinylpyridine)s (P2VPs) are important polymers with extensive applications in modern day material science. P2VP is an exceptional case for liquid chromatography because of certain polar interactions with most of the stationary phases. In the present study, we established the critical adsorption point (CAP) of P2VP for the first time. The effectiveness of the method is demonstrated by analyses of blends and block copolymers of P2VP and PMMA. The CAP of PMMA is established for determination of molar mass of P2VP component of above mentioned blends and block copolymers. The methods successfully demonstrate the separation of both types of homopolymers from the rest of the samples in conjunction with the determination of molar mass distribution of noncritical block or component. Graphical Abstract

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Synthesis,spectroscopic characterization,X-ray crystal structure,biological screening and catalytic studies of organotin(IV) carboxylates of 3-(4-cyanophenyl) acrylic acid

A series of six organotin(IV) carboxylates [Me₂SnL₂] (1), [n-Bu₂SnL₂] (2), [n-Oct₂SnL₂] (3), [Me₃SnL] (4), n-Bu₃SnL (5) and [Ph₃SnL] (6), where L = 3-(4-cyanophenyl) acrylic acid have been synthesized and characterized by elemental analysis, FT-IR and NMR (¹H, ¹³C). The complex (4) was also analyzed by single crystal X-ray analysis which showed distorted trigonal bipyramidal geometry with polymeric bridging behavior. The complexes 1–6 were screened for antimicrobial activities and cytotoxicity. The results showed significant activity with few exceptions. The catalytic activity of complexes was assessed in transesterification reaction of Brassica campestris oil (triglycerides) to produce biodiesel (fatty acid methyl esters). The results showed that triorganotin(IV) complexes exhibited good catalytic activity than their di-analogues.     

Imidazole,pyrimidine and diazepine containing heteroaryl-substituted heterocyclic salts as efficient ligand precursors for Mizoroki–Heck coupling reaction: synthesis,structural characterization and catalytic activities

The nine new heteroaryl-substituted imidazolidinium (1a–c), pyrimidinium (2a–c) and diazepinium (3a–c) salts as N-heterocyclic carbene (NHC) precursors were synthesized in good yields and entirely characterized using elemental analyses and conventional spectroscopic methods. In situ formed complexes from heterocyclic salts (1–3), Pd(OAc)₂ and in the presence of KOBu ^t as a base were tested as catalysts for the Mizoroki–Heck coupling reaction in an aqueous media and very high yields were achieved. 1,3-Di(5-methylthiophen-2-ylmethyl)pyrimidinium hexafluorophosphate salt (2b) was structurally characterized by single-crystal X-ray diffraction. In the 2b compound (C₁₆H₂₁N₂S₂)⁺[PF₆]^?, the terminal thiophene rings are twisted with a dihedral angle of 72.8(3)°. In the pyrimidine ring, the three successive C atoms between the N atoms are disordered over two positions [occupancy ratio 0.753(12):0.247(12)]. In the crystal, neighboring molecules are linked by C–H…F hydrogen bonds, running along the b axis.     

Steric and Electronic Influence on the Coordination Aptitude of 4‐Formylpiperazine‐1‐Carbodithioate Towards Triorganotin(IV) Moieties

A fascinating ligand, 4‐formylpiperazinium 4‐formylpiperazine‐1‐carbodithioate (L‐salt) has been reacted with two electronically and sterically different trimethyltin(IV) chloride and triphenyltin(IV) chloride. The complexes 1 and 2 were characterized by elemental analysis, spectroscopic techniques, and X‐ray single crystal analysis. The latter technique confirmed the polymeric and monomeric nature of 1 and 2 , respectively. Both 1 and 2 showed intriguing molecular packing properties in the solid state. However, the packing of 1 is more interesting and unique where one‐dimensional polymer chains self assemble in two‐over‐two saltire‐shaped fashion to provide an overall multilayered structure. The different behavior of L toward two different tin(IV) compounds can be attributed to different electronic and steric environments around metal center.     

Organotin(IV) Carboxylates of Substituted α‐Cinnamic Acid,RnSn(OCOC(R2)=CHR1)4 – n: Synthesis,Spectroscopic Characterization and Biological Evaluation

Di‐ and triorganotin(IV) carboxylates, R_nSn(OCOC(R²)=CHR¹)_4–n (n = 2 and 3; R = Me, Et, n‐Bu, Ph; R¹ = 3‐CH₃O‐4‐OHC₆H₃, R² = C₆H₅) were prepared by reacting the corresponding organotin(IV) chloride with the silver salt of the (E)‐3‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐phenylpropenoic acid. The title compounds were investigated and characterized by elemental analysis, infrared (FT‐IR), multinuclear (¹H, ¹³C, ¹¹⁹Sn) NMR, and mass spectrometry, and possible structures were proposed. The complexes and ligand acid ( HL ) have been evaluated in vitro against various bacteria and fungi. The results noticed during the biocidal activity screenings proved their in vitro biological potential. They were also tested for cytotoxicity.     

Numerical Modeling of Functional Fatigue in NiTi Wires

Motivated by the high potential of shape memory alloys (SMA) in several industrial applications, we investigate the material response under cyclic loading. In particular, the focus is set on the modelling of functional fatigue, which results in the deterioration of the specific features of SMA. In fact, functional fatigue restricts SMA in terms of its applicability for real structures and workpieces. This necessitates the development of material models which take this phenomenon into account. (© 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

二维配位聚合物[Tb(1,4⁃bdc)1.5(phen)(H2O)]n的合成、晶体结构及对Fe3+离子的荧光检测

通过溶剂热反应成功合成出一种新型2D配位聚合物[Tb(1,4-bdc)_1.5(phen)(H₂O)]_n(1)(1,4-H₂bdc=对苯二甲酸;phen=菲咯啉)。对其进行了单晶X射线衍射、粉末X射线衍射、红外光谱、元素分析、荧光光谱表征。X射线衍射晶体学分析表明,配合物1结晶于三斜晶系P1空间群,2个相邻的Tb(Ⅲ)离子与4个1,4-bdc^2-通过—O—C—O—桥联成双核单元,并进一步通过1,4-bdc^2-桥联成二维层状结构。荧光实验证明配合物1可以通过荧光猝灭机制检测Fe₃₊,Ksv=8.39×10³ L·mol-1,检测限为0.017μmol·L^-1。