胃癌靶向治疗药物临床实验研究进展

以往针对进展期胃癌进行化疗常作为其最佳治疗选择,但传统化疗不良反应大,耐药率高,成为治疗难点。近年来,分子靶向药物具有可选择性杀伤肿瘤细胞、药物不良反应小等优点,成为临床研究热点。以受体酪氨酸激酶为靶点的靶向药物联合化疗药物治疗胃癌的多项临床试验证实联合疗法可带来生存效益,将是胃癌治疗的有效手段。本文就胃癌靶向治疗药物临床实验研究进展进行综述。     

西昆仑铁克里克构造带康开铁矿床地质特征及成因

康开铁矿床位于西昆仑铁克里克构造带中段北缘,赋矿地层为元古代喀拉喀什岩群和埃连卡特岩群变质岩,发育镜铁矿和磁铁矿两种铁矿化类型。镜铁矿体受断层构造控制,呈脉状、似层状、团块状和细脉状产出。磁铁矿化体包括磁铁石英岩型和基性岩型,其中磁铁石英岩型矿石具有沉积变质型特征,基性岩型矿石表现为基性岩内发育浸染状磁铁矿和少量黄铜矿。依据两种铁矿化类型的矿物组合、结构构造、围岩蚀变和不同类型矿化体的时空关系等特征,将其成矿作用过程划分为沉积期、变质期、岩浆期和构造热液期4个成矿期,即该矿床是多期复合成矿作用的产物。沉积期和变质期形成的磁铁石英岩中的磁铁矿和岩浆期形成的基性岩中的磁铁矿为后期构造热液期发育的镜铁矿体提供了成矿元素来源,因此,出露于地表(浅部)的镜铁矿体可作为寻找周围和深部与磁铁石英岩和基性岩有关的磁铁矿的找矿标志,这一标志在铁克里克构造带中可能具有普遍性意义。     

Dense positrons and γ-rays generation by lasers interacting with convex target

We use quantum electrodynamics particle-in-cell simulation to study the generation of dense electron–positron plasma and strong γ-ray bursts in counter-propagating laser beam interactions with two different solid targets, i.e. planar(type I) and convex(type II). We find that type II limits fast electron flow most effectively. while the photon density is increased by about an order of magnitude and energy by approx. 10%–20% compared with those in type I target. γ-photon source with an ultrahigh peak brilliance of 2?×?1025 photons/s/mm2/mrad2/0.1% BW is generated by nonlinear Compton scattering process. Furthermore, use of type II target increases the positron density and energy by 3 times and 32% respectively, compared with those in type I target. In addition, the conversion efficiencies of total laser energy to γ-rays and positrons of type II are improved by 13.2% and 9.86% compared with type I. Such improvements in conversion efficiency and positron density are envisaged to have practical applications in experimental field.