Iridium‐mediated β‐deuteration of enones

Exposure of captodative enone systems to deuterium in the presence of Crabtree's catalyst ( 1 ) results in deuteration at the vinylic site β‐ to the ketone carbonyl, as well as at any accessible ortho‐position. β‐exchange is also observed during the reduction of ethyl cinnamate ( 3 ) catalyzed by 1 . Copyright © 2003 John Wiley & Sons, Ltd.     

Evaluation of a Thin-film Peripheral Nerve Cuff Electrode

Abstract

This is a study of the reaction of large nerves to implantation using a flexible, thin-film cuff electrode. Cuff electrodes were implanted on the sciatic nerve of three cats. An implantation period of six weeks allowed sufficient time for any injury responses in the nerve and connective tissue sheath around the cuff to develop. The electrode came off the nerve in one of the cats. In the remaining two cats, gross observation following explantation of the electrodes revealed encapsulation of the cuffs without swelling of nerve tissue. Histological evaluation did not demonstrate nerve injury. The nerve cuff electrodes, which are comprised of titanium and iridium coatings on a fluorocarbon polymer substrate, appeared unaffected by the implantation, and connective tissue encapsulation did not adhere to either the polymer substrate or metallization. Evaluation of the electrodes using activated iridium oxide charge injection sites in more extended studies is now being undertaken. (J Spinal Cord Med; 18:28–32)     

The iridium/iridium oxide electrode to in vivo measurement of oesophageal and gastric pH

An iridium-iridium oxide electrode for in vivo pH measurement of the distal oesophagus is described. It is small and flexible so it is well accepted by patients for long-term pH monitoring. The electrode also offers the possibility of including another electrode and/or a pressure sensor for simultaneous detection of two or more parameters—gastric pH or oesophageal pressure for example. A clinical study was performed on 15 healthy volunteers and the results were checked on a DGC Nova 4/s computer, showing less than 0.005% of tension in mV out of the established range in a period of 24 h pH monitoring. The volunteers' results were compared with the normal values obtained by DeMeester using a glass electrode on a similar, healthy group of American patients and no significant differences were observed.

Owing to its small size, reliability, fast response to pH changes, durability and its easy storage, the Ir/IrO₂ electrode is ideal for long-term pH monitoring of the upper gastro-intestinal tract.     

Evaluation of a P,N‐ligated iridium(I) catalyst in hydrogen isotope exchange reactions of aryl and heteroaryl compounds

We have developed a novel and efficient iridium‐catalyzed hydrogen isotope exchange reaction method with secondary and tertiary sulfonamides at ambient temperatures. Furthermore N‐oxides and phosphonamides have been successfully applied in hydrogen isotope exchange reactions with moderate to excellent deuterium introduction.     

Effect of Modification of Amorphous Silica with Ammonium Agents on the Physicochemical Properties and Hydrogenation Activity of Ir/SiO2 Catalysts

The modification of commercial silica with solutions of NH₄F or NH₄Cl salts, followed by thermal treatment, enabled generation of the acidic sites in SiO₂ and changed its textural properties. The use of ammonium salts solution also caused the generation of additional porosity. Using NH₄F solution caused significant decrease in the specific surface area and the increase in the average pore diameter. The number and strength of resulting acid sites depend on the nature of anion in the applied ammonium salt and the concentration of salt solution. It has been found that the sample treated with NH₄F presented higher total acidity (TPD–NH₃) and the amount as well as the strength of acid sites increased with the concentration of the used modifier. As modified amorphous SiO₂ materials used as a support for iridium (1 wt %, Ir(acac)₃) nanoparticles permitted to obtain highly active catalysts for toluene hydrogenation under atmospheric pressure. The highest activity (expressed as the apparent rate and TOF) was obtained for iridium catalysts supported on silica modified by NH₄F with the highest acidity. The modification of silica with NH₄F favors the generation of centers able to adsorb toluene, which results in higher activity of this catalyst.     

Visible-light-excited and europium-emissive nanoparticles for highly-luminescent bioimaging in vivo

Europium(III)-based material showing special milliseconds photoluminescence lifetime has been considered as an ideal time-gated luminescence probe for bioimaging, but is still limited in application in luminescent small-animal bioimaging in vivo. Here, a water-soluble, stable, highly-luminescent nanosystem, Ir–Eu–MSN (MSN = mesoporous silica nanoparticles, Ir–Eu = [Ir(dfppy)₂(pic–OH)]₃Eu·2H₂O, dfppy = 2-(2,4-difluorophenyl)pyridine, pic–OH = 3-hydroxy-2-carboxypyridine), was developed by an in situ coordination reaction to form an insoluble dinuclear iridium(III) complex-sensitized-europium(III) emissive complex within mesoporous silica nanoparticles (MSNs) which had high loading efficiency. Compared with the usual approach of physical adsorption, this in-situ reaction strategy provided 20-fold the loading efficiency (43.2%) of the insoluble Ir–Eu complex in MSNs. These nanoparticles in solid state showed bright red luminescence with high quantum yield of 55.2%, and the excitation window extended up to 470 nm. These Ir–Eu–MSN nanoparticles were used for luminescence imaging in living cells under excitation at 458 nm with confocal microscopy, which was confirmed by flow cytometry. Furthermore, the Ir–Eu–MSN nanoparticles were successfully applied into high-contrast luminescent lymphatic imaging in vivo under low power density excitation of 5 mW cm⁻². This synthetic method provides a universal strategy of combining hydrophobic complexes with hydrophilic MSNs for in vivo bioimaging.     

铱源驻留步长对宫颈癌三维近距离治疗计划的影响

目的:研究宫颈癌近距离治疗计划设计中,铱源驻留步长选择对计划评估及剂量稳定性的影响。方法:选取在安徽省肿瘤医院接受治疗的15例宫颈癌患者,均接受Fletcher型施源器植入的铱源高剂量率CT引导下近距离治疗。按照驻留步长大小分别为每位患者制定4组计划(Plan₁ mm、Plan₃ mm、Plan₅ mm和Plan₇ mm),对比治疗时长,靶区D₁₀₀、D₉₀和V₁₀₀和危及器官D_{2 cc}、SF系数等参数。模拟计算施源器发生脚向3 mm移位时剂量分布,分析施源器移位对不同驻留步长近距离治疗计划剂量学的参数影响。结果:不同驻留步长治疗计划的高危靶区(HRCTV)剂量学参数差异不明显(P>0.05),而Plan₁ mm、Plan₃ mm的中危靶区(IRCTV)的D₁₀₀、D₉₀、V₁₀₀和治疗时长均大于P...     

支气管动脉灌注与高剂量率支气管腔内放疗联合治疗非小细胞肺癌(附27例报道)

目的: 探讨支气管动脉灌注化疗(BAI) 与高剂量率支气管腔内后装放射治疗( HDRIBB) 两项新技术联合治疗非小细胞肺癌的可行性、方法学和临床价值。材料与方法: 对27 例非小细胞肺癌采用BAI 与铱192高剂量率支气管腔内后装放射治疗两项新技术进行序贯或交替方式的联合治疗,观察主、客观近期疗效、毒副反应与并发症。结果: 24 例有临床症状的患者,71 % (17/24) 得到不同程度的改善;27 例中92 .6 % (25/27) 的患者KPS 评分提高或稳定。近期客观缓解率:CR 8 例,PR 15 例,有效率(CR+ PR) 为85 % ;病理组织学疗效:显效2 例,有效5 例,部分有效2 例。结论: 支气管动脉灌注化疗与铱192 高剂量率支气管腔内后装放射治疗联合治疗非小细胞肺癌为有效方案,有较好的近期主、客观疗效,对中央型和周围型肺癌均适用。联合治疗安全可行,毒副反应及并发症轻微。联合治疗用于早期不能耐受手术的非小细胞肺癌的根治性治疗和综合治疗后局部残存或复发的治疗具有较大的临床研究价值     

Early wound complications in advanced head and neck cancer treated with surgery and Ir 192 brachytherapy

Objectives: Brachytherapy, either as primary or adjuvant therapy, is increasingly used to treat head and neck cancer. Reports of complications from the use of brachytherapy as adjuvant therapy to surgical excision have been limited and primarily follow Iodine 125 (I¹²⁵) therapy. Early complications include wound breakdown, infection, flap failure, and sepsis, and late complications may include osteoradionecrosis, bone marrow suppression, or carotid injuries. The authors sought to identify the early wound complications that follow adjuvant interstitial brachytherapy with iridium 192 (Ir¹⁹²). Study Design: A retrospective chart review of all patients receiving adjuvant brachytherapy at a tertiary medical center over a 4‐year period. Methods: Nine patients receiving Ir¹⁹² brachytherapy via afterloading catheters placed during surgical resection for close or microscopically positive margin control were evaluated. It was used during primary therapy in six patients and at salvage surgery in three. Early complications were defined as those occurring within 6 weeks of surgical therapy. Results: The overall complication rate was 55% (5/9), and included significant wound breakdown in two patients, minor wound dehiscence in three, and wound infection, bacteremia, and local tissue erosion in one patient each. All complications occurred in patients receiving flap reconstruction and one patient required further surgery to manage the complication. Complication rates were not associated with patient age, site, prior radiotherapy, timing of therapy, number of catheters, or dosimetry. Conclusions: The relatively high complication rate is acceptable, given the minor nature of most and the potential benefit of radiotherapy. Further study should be under‐taken to identify those patients who will achieve maximum therapeutic benefit without prohibitive local complications.     

Iridium(III) Complexes with PEO and PS Polymer Macroligands and Light‐Emitting Properties: Synthesis and Characterization

Summary: On the basis of terpyridine functionalized poly(ethylene oxide) (PEO) and poly(styrene) (PS), a series of light‐emitting iridium(III) compounds was effectively synthesized. The respective iridium(III) target compounds were prepared by grafting chloro‐bridged precursor complexes [Ir(ppy)₂‐μ‐Cl]₂ (ppy = phenylpyridine) and [Ir(ppy‐CHO)₂‐μ‐Cl]₂ (ppy‐CHO = 4‐(2‐pyridyl)benzaldehyde) onto terpyridine functionalized PEO and PS tails. 1D and 2D NMR characterization was performed revealing the expected resonances. Gel permeation chromatography (GPC) proved the stability and purity of the targeted materials. Preliminary investigations of the light‐emitting properties were carried out by standard methods such as UV‐vis and steady‐state luminescence spectroscopy. The morphology and the quality of films of these iridium(III) compounds were furthermore investigated using AFM. Improved stability on the electrode surface was illustrated using cyclic voltammetry. One of the polymer materials was compared to the neat complex, which showed quick degradation.

Green and orange light‐emitting iridium(III) complexes with two cyclometalating ligands and one terpyridine ligand with PS tails.