Evolution of the Microstructure and Phase Composition of the Products Formed in the Reaction between Iridium and W2B

In the present study, we perform a systematic examination of the products formed by mixing and heating of tungsten boride and iridium powders at different ratios in a broad temperature range using qualitative and quantitative X-ray analysis and time-of-flight neutron diffraction (TOF-ND), in combination with scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) performed at different accelerating voltages. The well-known and unknown ternary W–Ir–B phases were detected. The Vickers microhardness value for the new ternary W₂Ir₅B₂ boride was measured. Based on these findings, the ternary W₂Ir₅B₂ boride can be considered hard.     

Biliary tree malignancies: The University of Minnesota experience

Because of its slow-growing natural history, most patients with extrahepatic biliary tree malignancies present with inoperable disease. For the minority of patients with operable disease, surgical resection remains the treatment of choice and offers the patient the best chance for long-term local control. The role of chemotherapy and radiotherapy in the management of these patients in the definitive, adjuvant, and palliative setting is expanding, although unsettled. Response rates with chemotherapy have been low and will most likely find a place in a combined multimodality setting. Radiotherapy (external beam, intraoperative, and intraluminal brachytherapy using ¹⁹²Ir) has played a major role in the treatment of these cancers. The close proximity of bowel, kidney, and liver limits the external beam radiotherapy doses that can be safely delivered. Since most patients require placement of percutaneous transhepatic biliary catheters to relieve jaundice, this route has been utilized to deliver higher doses of radiation to the tumor area with intraluminal ¹⁹²Ir ribbons. The University of Minnesota has treated 15 patients with extrahepatic bile duct cancers. Most were located at the bifurcation of the common bile duct and were treated with intraluminal brachytherapy alone or with external beam radiotherapy. Our results are comparable to previously reported retrospective data with a median survival of 8 months and three long-term survivors. J. Surg. Oncol. 1997;65:298–305. © 1997 Wiley-Liss, Inc.     

Alternative efficient tritium labeling of repaglinide

There is a need for an efficient tritium labeling methodology for repaglinide to support numerous in vitro and in vivo studies. Numerous homogeneous and heterogeneous catalysts were screened for their capacity to tritiate repaglinide directly without the need to synthesize suitable precursors and to avoid multistep synthesis. In particular, boosting effects using a combination of homogeneous and heterogeneous catalysts were examined. Finally, a suitable method was selected for tritation and resulted in an efficient tritation of repaglinide via a heterogeneous catalyzed hydrogen–tritium exchange reaction with iridium black as the preferred catalyst.     

"Largest amplitude ablation" is the optimal approach for typical atrial flutter ablation: a subanalysis from the AURUM 8 study

Voltage‐Guided Cavotricuspid Isthmus Ablation. Introduction: The recently proposed “maximum voltage‐guided” (MVG) technique for radiofrequency catheter ablation of atrial flutter targets high‐voltage electrograms along cavotricuspid isthmus (CTI) to ablate the functionally important anatomic muscle bundles alone, without drawing a complete anatomic line across the CTI. This innovative approach may shorten ablation time and procedure duration. Methods and Results: Within the multicenter AURUM 8 study, which compared 8‐mm gold‐ and Pt‐Ir‐tip catheters in atrial flutter ablation, we made a post hoc comparison of procedural data from 72 patients treated with MVG technique with data from 281 patients undergoing anatomic CTI ablation (unmatched) and with data from 72 patients selected from among those 281 patients such that they were matched with the MVG group with respect to selected baseline parameters and catheter type (matched). The MVG technique markedly reduced (P < 0.001) ablation time (mean 6.9 minutes vs 10.9/9.7 minutes [unmatched/matched]), number of lesions (8.3 vs 13.7/12.9), fluoroscopy time (9.5 minutes vs 20.6/17.9 minutes), procedure duration (59 minutes vs 93/86 minutes), and energy delivered (19 kJ vs 34/30 kJ) compared with anatomic CTI ablation. The incidence of charring was higher for MVG than for anatomic ablation technique (31.9% vs 18.5/15.3%, P < 0.05), where Pt‐Ir tip catheters were 6‐fold more susceptible to charring than gold‐tip catheters (P < 0.001), likely because of a lower thermal conductivity of the Pt‐Ir material. The acute success rate was slightly better for MVG than for anatomic ablation technique (97.2% vs 92.2/91.7%, P = n.s.). Conclusion: Major procedural parameters are remarkably improved with MVG technique. Gold‐tip catheters are substantially less susceptible to charring and may therefore be preferred over Pt‐Ir‐tip catheters for MVG ablation technique. (J Cardiovasc Electrophysiol, Vol. 23, pp. 479‐485, May 2012)     

The Photoluminescent Properties of New Cationic Iridium(III) Complexes Using Different Anions and Their Applications in White Light-Emitting Diodes

Three cationic iridium(III) complexes [Ir(ppy)₂(phen)][PF₆] (C1), [Ir(ppy)₂(phen)]₂SiF₆ (C2) and [Ir(ppy)₂(phen)]₂TiF₆ (C3) (ppy: 2-phenylpyridine, phen: 1, 10-phenanthroline) using different anions were synthesized and characterized by ¹H Nuclear magnetic resonance (¹HNMR), mass spectra (MS), Fourier transform infrared (FTIR) spectra and element analysis (EA). After the ultraviolet visible (UV-vis) absorption spectra, photoluminescent (PL) properties and thermal properties of the complexes were investigated, complex C1 and C3 with good optical properties and high thermal stability were used in white light-emitting diodes (WLEDs) as luminescence conversion materials by incorporation with 460 nm-emitting blue GaN chips. The integrative performances of the WLEDs fabricated with complex C1 and C3 are better than those fabricated with the widely used yellow phosphor Y₃Al₅O₁₂:Ce³⁺ (YAG). The color rendering indexes of the WLEDs with C1 and C3 are 82.0 and 82.6, the color temperatures of them are 5912 K and 3717 K, and the maximum power efficiencies of them are 10.61 Lm·W⁻¹ and 11.41 Lm·W⁻¹, respectively.     

A Process for Hydrogen Production from the Catalytic Decomposition of Formic Acid over Iridium—Palladium Nanoparticles

The present study investigates a process for the selective production of hydrogen from the catalytic decomposition of formic acid in the presence of iridium and iridium–palladium nanoparticles under various conditions. It was found that a loading of 1 wt.% of 2% palladium in the presence of 1% iridium over activated charcoal led to a 43% conversion of formic acid to hydrogen at room temperature after 4 h. Increasing the temperature to 60 °C led to further decomposition and an improvement in conversion yield to 63%. Dilution of formic acid from 0.5 to 0.2 M improved the decomposition, reaching conversion to 81%. The reported process could potentially be used in commercial applications.     

192Ir核素脑胶质瘤间质内放疗的研究及其临床应用

为观察用＾１９２Ｉｒ后装治疗脑胶质瘤间后内放疗的有效性及其并发症,用皮荷瘤鼠和脑荷瘤鼠模型行间质内放疗实验,证明在内照射后可抑制肿瘤生长及延长鼠的生存期的可靠基础上,对７２例脑胶质瘤采用＾１９２Ｉｒ后装机行瘤间后内近距离照射,取得良好疗效。手术无何严重并发症,无死亡。术后随访１－５年,生存率分别为９２％、８２％、７２％、５６％及３２％,表明生存期显著延长。结论脑深部胶质瘤用＾１９２Ｉｒ核素瘤间持     

一种新型铱(Ⅲ)配合物探针分子的制备及其依次对铜离子和硫化氢的识别

目的 设计一个新型铱配合物荧光探针分子Ir-cyc,以质谱分析为主要手段确定产物的结构并分析其对Cu2+及H2S的荧光响应.方法 以2-苯基吡啶(2-phenylpyridine,ppy)及三氯化铱(iridium trichloride,IrCl3)为原料,制备桥式铱前配物[Ir(ppy)2 Cl]2;以5-氨基邻菲...     

P Wave Recognition and Atrial Stimulation with Fractally Iridium Coated VDD Single Pass Leads

The bottleneck of VDD systems is the reliable detection of the small atrial signals by a floating atrial electrode. Fractally iridium coated electrodes offer excellent sensing and pacing performance. In this study, the performance of such a floating atrial lead in P wave sensing and synchronous ventricular stimulation was examined. Atrial pacing was also used as a test of atrial wall contact. Patients and Methods : A fractally iridium coated VDDlead was implanted in 18 patients. In 15 patients it was interfaced with a VDD pacemaker and in 3 patients with a DDD system depending on the P wave amplitude measured acutely (≥ 2 mV). Simultaneous recordings of the surface ECG and pacemaker telemetry were used to analyze P wave amplitudes and AV synchrony in different body positions, and during normal and deep breathing. Additionally, exercise tests based on daily life activities and 24-hour ECG monitoring were performed to test the pacemaker function. Results : During implantation P wave amplitudes were 1.86 mV ± 1.08 mV (range 0.5–4.9 mV) and during follow-up (6.6 ± 5.6 weeks) 0.18–3.8 mV. Holter recordings revealed reliable P wave sensing at a sensitivity setting of 0.5 mV (95.5%). P wave sensing was further improved by a higher atrial sensitivity. AV synchronous pacing ± 99.9% was achieved in all patients. In 7 patients the atrial electrode could be positioned close to the atrial wall enabling atrial stimulation thresholds at an average of 4.3 volts. Conclusion : This fractally iridium coated VVD lead allowed consistent and reliable P wave sensing at an atrial sensitivity as low as 0.5 mV in selected patients.     

间质内放疗治疗复发胶质瘤

[目的]探讨立体定向铱192核素间质内放疗治疗高度恶性复发胶质瘤的疗效。[方法]对23例Ⅲ～Ⅳ期胶质瘤患者行铱192核素高剂量率间质内放疗。[结果]临床症状和体征消失5例。改善12例。无效或恶化5例。无严重并发症发生。1年生存率为ll％，复发后平均生存期为6．2个月。[结论]立体定向铱192核素间质内放疗能延长病人的生存期及改善生存质量。安全有效,并发症少。