Magnetron Sputtered CsPbCl3 Perovskite Detectors as Real-Time Dosimeters for Clinical Radiotherapy

The aim of this study is to investigate the feasibility of manufacturing thin real-time relative dosimeters for clinical radiotherapy (RT) with potential applications for transmission monitoring in vivo dosimetry and pre-treatment dose verifications. Thin (≈1 μm) layers of a high sensitivity, wide bandgap semiconductor, the inorganic perovskite CsPbCl₃, have been grown for the first time by magnetron sputtering on plastic substrates equipped with electrode arrays. Prototype devices have been tested in real-time configuration to evaluate the dose delivered by a 6 MV photon beam from a linear accelerator. Linearity of the charge with the dose has been verified over three order of magnitudes, linearity of the current signal with the dose rate has been also successfully tested in the range 0.5-4.3 Gy/min. The combination of high sensitivity per unit volume and wide bandgap provides high signal-to-noise ratios, up to 70, even at moderate applied voltages. The Schottky diode configuration allows the detector to operate without bias voltage (null bias).The blocking-barrier structure allows to confine the active volume within sub-millimetric sizes, a quite attractive feature in view to increase granularity and achieve the high spatial resolutions required in modern RT techniques. All the above-mentioned features indeed pave the way to a novel generation of flexible, transmission, real time dosimeters for clinical radiotherapy.     

提高选题策划质量 提升行业期刊品牌影响力——以金属加工杂志社实践为例

【目的】 探讨行业期刊进行选题策划的方法,提升选题策划的质量。【方法】 利用互联网技术及新媒体资源,结合金属加工杂志社选题策划实例,归纳出几种选题策划的途径及方法。【结果】 结合行业热点进行选题策划,注重实效性和内容深度,提升期刊内容的可读性,可使期刊获得更多读者的关注和认可,提升期刊的行业影响力。【结论】 提高选题策划质量,可有效提升期刊内容的可读性,从而进一步提升期刊在行业的影响力。     

超声引导金属弹簧圈定位乳腺肿块的临床应用

目的探讨乳腺肿块金属弹簧圈标记的临床应用价值。方法对13例触诊不清的乳腺良性肿块,41例新辅助化疗的乳腺癌,在超声引导下行术前边界定位及肿块标记。事先测量好肿块最大直径,选择相应长度的金属弹簧圈,通过18G穿刺针,用导丝准确将弹簧圈放入肿物最大切面两极。41例乳腺癌定位后继续化疗2~3个周期。结果13例触诊不清的乳腺良性肿块连同其内的弹簧圈被准确、完整切除。41例乳腺癌中,术后弹簧圈周边即肿物切缘病理未见残留癌细胞术前化疗期间,经超声观察,39例肿块缩小,其中9例术前超声显示肿物边界已显示不清,只显示金属弹簧圈,这其中3例术后肿物连续病理切片,证实未见癌细胞。结论超声引导下金属弹簧圈肿物边缘定位,对触诊不清的乳腺肿块边界定位是一种新方法。特别是对于术前化疗的乳腺癌患者,在肿块超声随访、化疗疗效评价以及指导术后病理取材部位等方面有更实用的临床意义。     

Inhibition of the amorphous calcium phosphate phase transformation reaction by polyphosphates and metal ions

Summary The induction time for amorphous calcium phosphate (ACP) phase transformation was monitored at pH 7.4 and T=25°C with [Ca²⁺]₀=[PO₄]₀=4.0×10⁻³ M, as a function of added crystal growth inhibitors Mg²⁺, Sr²⁺, Zn²⁺, pyrophosphate (PP), and tripolyphosphate (TPP). Metal ions increase the induction time for the initiation of the phase change reaction in the order Zn²⁺<Sr²⁺<Mg²⁺. For polyphosphates it was observed that both PP and TPP are potent inhibitors with TPP more effective than PP as expected. The combination of Mg²⁺ or Sr²⁺ and PP or TPP leads to a synergistic delay in the onset of the phase conversion. The greatest inhibition was observed for Mg²⁺ and TPP. Reaction solutions containing 2.0×10⁻⁴ M Mg²⁺ and 4.0×10⁻⁵ M TPP resulted in a 90% increase in the induction time over what would be anticipated from an additive effect from these species.     

人血管抑制因子的原核表达、纯化及活性研究

目的：利用大肠杆菌表达系统表达人血管抑制因子，并利用镍金属螯合层析法进行纯化，探讨其抑制血管内皮细胞增殖的活性。方法：采用RT-PCR技术从人肝脏组织中获取人血管抑制因子的cDNA，将其克隆至原核表达载体pQE30中进行IPTG诱导表达。表达产物经SDS-PAGE分析，并利用镍金属螯合层析法进行纯化。^3H-TdR法检测纯化的血管抑制因子对血管内皮细胞增殖的抑制作用。结果：利用pQE30表达载体表达的含6个组氨酸尾的vasostafin蛋白，在SDS-PAGE上表现出一条约2lkD的阳性条带，经镍金属螯合层析纯化后的蛋白经肽指纹图谱分析鉴定为目的蛋白，在体外可抑制人脐静脉血管内皮细胞的增殖。结论：人血管抑制因子可在大肠杆菌中以包涵体形式高水平表达，并具有抑制血管内皮细胞增殖的活性．     

科技期刊全媒体平台建设思维探究——以金属加工全媒体平台为例

【目的】 通过对金属加工杂志社搭建的全媒体平台(以下简称“金属加工全媒体平台”)特色和建设思维的研究,为科技类期刊的全媒体平台建设提供借鉴。【方法】 采用访谈法、观察法和个案分析法等对金属加工全媒体平台的建设和运营情况进行资料收集、思考和分析。【结果】 金属加工全媒体平台的特色在于它不仅是不断延展的开放式平台,也是优质内容的一站式平台,更是用户导向的服务平台,亦是杂志社主导的共建性平台。【结论】 虽然金属加工杂志社的“大而全型”全媒体平台只是科技类期刊全媒体平台的一种类型,但其平台建设中的差异化思维、用户思维和融合思维具有普适性,可以为其他科技期刊的全媒体平台建设提供参考。     

中药中金属元素的生化作用机理

机体内环境是一个多层次纵横交错的大系统 ,有一套复杂的调控体系 ,金属元素与此调控体系有密切联系。机体内所有复杂的生化反应都离不开酶 ,而金属元素有的是酶的辅助因子参与酶的组成 ,有的是酶的激活剂 ,是酶活性的主要调节者。深入研究中药中金属元素对酶活性的影响 ,将有利于提高药效。此外肾虚病人血清中金属元素与正常人相比有显著差异 ,若能比较准确地测得肾虚不同阶段的金属元素图谱 ,并结合中药中各金属元素含量的不同加以针对性地治疗 ,将对提高药物对疾病的治疗效果及延缓衰老有重要意义。     

Methods to address metal artifacts in post-processed CT images – A do-it-yourself guide for orthopedic surgeons

Computed tomography (CT) scans are often used for postoperative imaging in orthopedics. In the presence of metallic hardware, artifacts are generated, which can hamper visualization of the CT images, and also render the study ineffective for 3-D printing. Various solutions are available to minimize metal artifacts, and radiologists can employ these before or after processing the CT study. However, the orthopedic surgeon may be faced with situations where the metal artifacts were not addressed. To counter such problems, we present three do-it-yourself (DIY) techniques that can be used to manage metal artifacts.     

金属卟啉作为双功能模拟酶的研究

根据超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性结构相似原理,作者首次提出金属卟啉化合物可作为SOD和CAT双功能模拟酶,并对合成的4 种金属卟啉[四-(对磺酸基苯基)卟啉铁、四-(对磺酸基苯基)卟啉铜、四-(对磺酸基苯基)卟啉锰、四-(对磺酸基苯基)卟啉钴]进行了仿SOD和CAT的部分生物学功能检测 .结果显示:核黄素-蛋氨酸光明法证实它们在10-5～10-6mol/L浓度范围内有清除O(*2)-的作用;分光光度法证实它们能催化H2O2 的分解,且分解率随浓度增大而增大;用小鼠肝匀浆法测定4种金属卟啉、SOD和CAT,均表明有良好抗脂质过氧化作用;大鼠心脏缺血再灌注实验表明四-(对-磺酸基苯基)卟啉锰能降低活性氧对心肌的损伤程度, 对再灌注损伤心肌有保护作用.     

Manganese exposure in foundry furnacemen and scrap recycling workers

Objectives: Cast iron products are alloyed with small quantities of manganese, and foundry furnacemen are potentially exposed to manganese during tapping and handling of smelts. Manganese is a neurotoxic substance that accumulates in the central nervous system, where it may cause a neurological disorder that bears many similarities to Parkinson's disease. The aim of the study was to investigate the sources and levels of manganese exposure in foundry furnacemen by a combined measuring of blood-manganese (B-Mn) and manganese in ambient air (air-Mn). Methods: During a period of 16 months, Air-Mn and B-Mn (denoted `exposure values') were measured involving 24 furnacemen employed in three small size foundries and 21 scrap recycling workers from one plant. In the study period, 18 furnacemen had B-Mn measured 3–4 weeks after decreasing or stopping exposure (denoted `post-exposure values'). The reference group for the B-Mn measurements consisted of 90 Danish male subjects. Results: Furnacemen who work in insufficiently ventilated smelting departments inhale, absorb, and retain significant amounts of manganese in their blood (approx. 2.5–5 μg/l above reference values) despite a generally low measured airborne level of manganese fumes (0.002–0.064 mg/m³). The `exposure values' compared with `post-exposure values' revealed a significant decrease in the B-Mn (on average 3.7 μg/l) level of the most exposed furnacemen. Two persons in our study were suspected of suffering clinically subacute manganese intoxication as both had B-Mn levels beyond the normal limit (25 and 29 μg/l, respectively). The potential problem disappeared completely after cessation of exposure, and the B-Mn levels decreased to 9.4 and 14.1 μg/l, respectively. Conclusions: Risk assessment based on combined measurements of B-Mn and air-Mn seems to be valid in the interpretation of workers' hazard. Our study indicates that B-Mn may be a valuable parameter for estimating recent exposure (within 1–2 weeks). However, more knowledge is needed about the B-Mn level and its relation to neurological symptoms. Received: 20 January 1999 / Accepted: 14 June 1999