镓合金和银汞合金的比较研究Ⅰ耐磨性,腐蚀性和菌斑附着情况

本文比较了镓合金与银汞合金两种牙体修复材料的耐磨性、腐蚀性及菌斑附着情况。探讨镓合金在临床上被选用的可能性。体外实验的结果显示，银汞合金的耐磨性和耐腐蚀性均优于镓合金，并有显著性差异。银汞合金充填体的菌斑指数及菌落计数均低于镓合金充填体，也有高度显著性差异。     

镓合金骨埋植的组织学实验研究

目的：比较镓合金和银汞合金、玻璃离子体水门汀的骨组织学反应，探讨镓合金作为根尖切除术后倒充填材料的可行性。方法：麻醉下切开48只大耳兔的股骨，暴露股骨干，每间隔5mm钻直径1mm的埋植小孔4个，自上而下依次植入镓合金、玻璃离子体水门汀、银汞合金和空白对照，进行组织学及X线对照观察。动物分别于7、28、84、168d处死，取标本制片，进行组织学观察。组织学反应以距离植入体100μm内的浆细胞、淋巴细胞、多形核白细胞、巨噬细胞、破骨细胞数目评估。骨形成以同一区域内成骨细胞存在与否判定。x线片检查分别于手术后当天及4个取材期进行。结果：镓合金植入体100μm范围内28、84d骨形成统计学上有明显差异，玻璃离子体水门汀在整个实验期内无显著差异，而银汞合金组在整个实验期内都有明显差异。镓合金组7、28d淋巴细胞浸润统计学上有明显差异，玻璃离子体水门汀组从28、84d淋巴细胞浸润有明显下降，银汞合金组从7d--84d淋巴细胞浸润有明显差异。结论：镓合金与银汞合金有相似的生物相容性，并且镓合金的细胞毒性略低于银汞合金，为镓合金作为根尖切除术后倒充填材料及龋齿窝洞充填材料的临床应用提供了依据。     

硝酸镓对临床分离金黄色葡萄球菌生物膜的体外清除作用

目的研究新型抗菌剂硝酸镓对金黄色葡萄球菌生物膜的清除作用,探索抑制细菌生物膜的新方法。方法采用结晶紫染色法,对临床分离的14株金黄色葡萄球菌进行生物膜阳性菌株筛选,检测硝酸镓对生物膜阳性菌株的最低抑菌浓度(MIC)和对生物膜的清除作用。结果 14株金黄色葡萄球菌中,生物膜阳性菌株9株。硝酸镓对金黄色葡萄球菌ATCC25923、生物膜阴性菌株以及9株生物膜阳性菌株的MIC均为16μg/mL。硝酸镓对金黄色葡萄球菌早期生物膜的清除率为(86.53±0.96)%,高于对晚期生物膜的清除率[(62.54±1.53)%](t=35.699,P0.001)。结论硝酸镓具有抑制金黄色葡萄球菌增殖,清除其生物膜的作用,有望成为防治金黄色葡萄球菌感染的新型药物。     

A novel PET tracer for the imaging of αvβ3 and αvβ5 integrins in experimental breast cancer bone metastases

The aim of this study was the evaluation of ⁶⁸Ga‐DOTA‐E‐[c(RGDfK)]₂ as a novel PET tracer to image αvβ3 and αvβ5 integrins. For this purpose, DOTA‐E‐[c(RGDfK)]₂ was labeled with ⁶⁸Ga, which was obtained from a ⁶⁸Ge/⁶⁸Ga generator, purified by solid‐phase extraction and the radiochemical purity analyzed by radio‐RP‐HPLC. ⁶⁸Ga‐DOTA‐E‐[c(RGDfK)]₂ was obtained reproducibly in radiochemical yields of 60 ± 6% and with an excellent radiochemical purity of >99%. In nude rats bearing bone metastases after injection of MDA‐MB‐231 human breast cancer cells, biodistribution studies were performed to evaluate the accumulation of the radiotracer in selected organs, blood and bone metastases 0.5, 1, 2 and 3 h post injection. A rapid uptake into the bone metastases and rapid blood clearance was observed, resulting in tumor–blood ratios of up to 26.6 (3 h post injection) and tumor–muscle ratios of up to 7.9 (3 h post injection). A blocking experiment with coinjected αvβ3/αvβ5 antagonist showed the tumor uptake to be receptor‐specific. In an initial in vivo micro PET evaluation of the tracer using the same animal model, the bone metastasis was clearly visualized. These results suggest that ⁶⁸Ga‐DOTA‐E‐[c(RGDfK)]₂ is a promising PET tracer suitable for the imaging of αvβ3 and αvβ5 integrins in bone metastases. This novel PET tracer should be further evaluated concerning its usefulness for early detection of bone metastases and monitoring treatment response of these lesions. Copyright © 2011 John Wiley & Sons, Ltd.     

氯化镓治疗去卵巢大鼠骨质疏松的实验观察

目的 探讨镓对去卵巢大鼠骨质疏松的治疗作用。方法 通过切除大鼠卵巢建立骨质疏松模型，经氯化镓治疗12周后，用单光子法测量骨密度；放免法检测相关血清学指标；测定骨病理形态学指标。结果 氯化镓治疗组血清抗酒石酸酸性磷酸酶、骨小梁间距低于骨质疏松对照组，而骨密度和骨小梁宽度高于骨质疏松对照组。结论 镓对去卵巢所致大鼠的骨质疏松有效。     

Fabrication of a Flexible Photodetector Based on a Liquid Eutectic Gallium Indium

A fluidic gallium-based liquid metal (LM) is an interesting material for producing flexible and stretchable electronics. A simple and reliable method developed to facilitate the fabrication of a photodetector based on an LM is presented. A large and thin conductive eutectic gallium indium (EGaIn) film can be fabricated with compressed EGaIn microdroplets. A solution of LM microdroplets can be synthesized by ultrasonication after mixing with EGaIn and ethanol and then dried on a PDMS substrate. In this study, a conductive LM film was obtained after pressing with another substrate. The film was sufficiently conductive and stretchable, and its electrical conductivity was 2.2 × 10⁶ S/m. The thin film was patterned by a fiber laser marker, and the minimum line width of the pattern was approximately 20 μm. Using a sticky PDMS film, a Ga₂O₃ photo-responsive layer was exfoliated from the fabricated LM film. With the patterned LM electrode and the transparent photo-responsive film, a flexible photodetector was fabricated, which yielded photo-response-current ratios of 30.3%, 14.7%, and 16.1% under 254 nm ultraviolet, 365 nm ultraviolet, and visible light, respectively.     

Automated production of [68Ga]Ga‐DOTANOC and [68Ga]Ga‐PSMA‐11 using a TRACERlab FXFN synthesis module

The interest in gallium‐68 labelled positron‐emission tomography probes continues to increase around the world. However, one of the barriers for routine clinical use is the cost of the automated synthesis units for relatively simple labelling procedures. Herein, we describe the adaptation of a TRACERlab FX_FN synthesis module for the automated production of gallium‐68 radiopharmaceuticals using a cation‐exchange cartridge for postprocessing of the ⁶⁸Ge/⁶⁸Ga generator eluate. The recovery of activity from the cartridge was 95.6% to 98.9% using solutions of acidified sodium chloride (5 M with pH = 1‐3). The radiosyntheses of [⁶⁸Ga]Ga‐DOTANOC and [⁶⁸Ga]Ga‐PSMA‐11 were performed using acetate sodium buffer or 4‐(2‐hydroxyethyl)piperazine‐1‐ethanesulfonic acid, with a total duration of 21 and 23 minutes, respectively, including generator elution and radiopharmaceutical dispensing. Activity yields were 77% ± 2% for [⁶⁸Ga]Ga‐PSMA‐11 and 68% ± 3% for [⁶⁸Ga]Ga‐DOTANOC (n > 100). The labelled peptides had a radiochemical purity exceeding 97%, and all quality control parameters were in conformity with the limits prescribed by the European Pharmacopoeia.     

Nitrogen Dissolution in Liquid Ga and Fe: Comprehensive Ab Initio Analysis,Relevance for Crystallization of GaN

The dissolution of molecular nitrogen in Ga and Fe was investigated by ab initio calculations and some complementary experiments. It was found that the N bonding inside these solvents is fundamentally different. For Ga, it is between Ga4s and Ga4p and N2p states whereas for Fe this is by N2p to Fe4s, Fe4p and Fe3d states. Accordingly, the energy of dissolution of N2 for arbitrarily chosen starting atomic configurations was 0.535 eV/mol and −0.299 eV/mol for Ga and Fe, respectively. For configurations optimized with molecular dynamics, the difference between the corresponding energy values, 1.107 eV/mol and 0.003 eV/mol, was similarly large. Full thermodynamic analysis of chemical potential was made employing entropy-derived terms in a Debye picture. The entropy-dependent terms were obtained via a normal conditions path to avoid singularity of ideal gas entropy at zero K. Nitrogen solubility as a function of temperature and N2 pressure was evaluated, being much higher for Fe than for Ga. For T=1800 K and p=104 bar, the N concentration in Ga was 3×10−3 at. fr. whereas for Fe, it was 9×10−2 at. fr. in very good agreement with experimental data. It indicates that liquid Fe could be a prospective solvent for GaN crystallization from metallic solutions.     

Ultrafast Third-Order Nonlinear Optical Response Excited by fs Laser Pulses at 1550 nm in GaN Crystals

The ultrafast third-order optical nonlinearity of c-plane GaN crystal, excited by ultrashort (fs) high-repetition-rate laser pulses at 1550 nm, wavelength important for optical communications, is investigated for the first time by optical third-harmonic generation in non-phase-matching conditions. As the thermo-optic effect that can arise in the sample by cumulative thermal effects induced by high-repetition-rate laser pulses cannot be responsible for the third-harmonic generation, the ultrafast nonlinear optical effect of solely electronic origin is the only one involved in this process. The third-order nonlinear optical susceptibility of GaN crystal responsible for the third-harmonic generation process, an important indicative parameter for the potential use of this material in ultrafast photonic functionalities, is determined.