GRW as an ontology of dispositions

The paper argues that the formulation of quantum mechanics proposed by Ghirardi, Rimini and Weber (GRW) is a serious candidate for being a fundamental physical theory and explores its ontological commitments from this perspective. In particular, we propose to conceive of spatial superpositions of non-massless microsystems as dispositions or powers, more precisely propensities, to generate spontaneous localizations. We set out five reasons for this view, namely that (1) it provides for a clear sense in which quantum systems in entangled states possess properties even in the absence of definite values; (2) it vindicates objective, single-case probabilities; (3) it yields a clear transition from quantum to classical properties; (4) it enables to draw a clear distinction between purely mathematical and physical structures, and (5) it grounds the arrow of time in the time-irreversible manifestation of the propensities to localize.     

诺贝尔奖获得者与20世纪的物理学

本书介绍了诺贝尔物理学奖。作者使用了原创的方法介绍了20世纪物理学的主要成就，例如：相对论、超导体、脉冲双星和玻色一爱因斯坦凝聚。这些成就都显现出获奖者的天才并因此而戴上了诺贝尔奖的桂冠。书中以获奖者本人的言语及丰富的图像来介绍20世纪最著名的物理学家的工作——波尔、居里、爱因斯坦、费米、费曼、盖尔曼、海森堡、卢瑟福、薛定谔。     

Replication fork movement sets chromatin loop size and origin choice in mammalian cells

Genome stability requires one, and only one, DNA duplication at each S phase. The mechanisms preventing origin firing on newly replicated DNA are well documented, but much less is known about the mechanisms controlling the spacing of initiation events(2,3), namely the completion of DNA replication. Here we show that origin use in Chinese hamster cells depends on both the movement of the replication forks and the organization of chromatin loops. We found that slowing the replication speed triggers the recruitment of latent origins within minutes, allowing the completion of S phase in a timely fashion. When slowly replicating cells are shifted to conditions of fast fork progression, although the decrease in the overall number of active origins occurs within 2 h, the cells still have to go through a complete cell cycle before the efficiency specific to each origin is restored. We observed a strict correlation between replication speed during a given S phase and the size of chromatin loops in the next G1 phase. Furthermore, we found that origins located at or near sites of anchorage of chromatin loops in G1 are activated preferentially in the following S phase. These data suggest a mechanism of origin programming in which replication speed determines the spacing of anchorage regions of chromatin loops, that, in turn, controls the choice of initiation sites.     

Identification and expansion of human colon-cancer-initiating cells

Colon carcinoma is the second most common cause of death from cancer. The isolation and characterization of tumorigenic colon cancer cells may help to devise novel diagnostic and therapeutic procedures. Although there is increasing evidence that a rare population of undifferentiated cells is responsible for tumour formation and maintenance, this has not been explored for colorectal cancer. Here, we show that tumorigenic cells in colon cancer are included in the high-density CD133+ population, which accounts for about 2.5% of the tumour cells. Subcutaneous injection of colon cancer CD133+ cells readily reproduced the original tumour in immunodeficient mice, whereas CD133- cells did not form tumours. Such tumours were serially transplanted for several generations, in each of which we observed progressively faster tumour growth without significant phenotypic alterations. Unlike CD133- cells, CD133+ colon cancer cells grew exponentially for more than one year in vitro as undifferentiated tumour spheres in serum-free medium, maintaining the ability to engraft and reproduce the same morphological and antigenic pattern of the original tumour. We conclude that colorectal cancer is created and propagated by a small number of undifferentiated tumorigenic CD133+ cells, which should therefore be the target of future therapies.     

Multifunctional to multistage delivery systems: The evolution of nanoparticles for biomedical applications

Nanomaterials are advancing in several directions with significant progress being achieved with respect to their synthesis, functionalization and biomedical application. In this review, we will describe several classes of prototypical nanocarriers, such as liposomes, silicon particles, and gold nanoshells, in terms of their individual function as well as their synergistic use. Active and passive targeting, photothermal ablation, and drug controlled release constitute some of the crucial functions identified to achieve a medical purpose. Current limitations in targeting, slow clearance, and systemic as well as local toxicity are addressed in reference to the recent studies that attempted to comprehend and solve these issues. The demand for a more sophisticated understanding of the impact of nanomaterials on the body and of their potential immune response underlies this discussion. Combined components are then discussed in the setting of multifunctional nanocarriers, a class of drug delivery systems we envisioned, proposed, and evolved in the last 5 years. In particular, our third generation of nanocarriers, the multistage vectors, usher in the new field of nanomedicine by combining several components onto multifunctional nanocarriers characterized by emerging properties and able to achieve synergistic effects.     

孕期高雄大鼠子代实验性多囊卵巢综合征模型构建

通过母体高雄环境建立子代实验性多囊卵巢综合征(PCOS)大鼠模型,并证明此模型大鼠存在卵巢局部胰岛素抵抗。方法是给孕16d的雌鼠皮下注射丙酸睾丸酮,诱导其子代雌鼠发生PCOS,观察子代大鼠体重、动情周期变化、性激素变化及糖代谢变化、卵巢重量和卵巢形态变化、肌肉组织蛋白印迹测定PI-3K和MAPK通路关键蛋白的表达、卵巢免疫组化和蛋白印迹测定PI-3K和MAPK通路关键蛋白的表达确定。结果显示:①动情周期失去规律变化,提示无排卵;②血清17-OHP,A2,T升高;③卵巢组织学检查可镜下看到早期发育的较多的小卵泡、闭锁卵泡,囊状扩张卵泡明显增加,颗粒细胞层数减少,黄体数量明显减少;④OGTT:1h血糖及胰岛素高于对照组,模型组存在着胰岛素抵抗;⑤卵巢局部PI-3K和MAPK途径关键蛋白有表达;⑥卵巢局部蛋白印迹测定PI-3K和MAPK途径关键蛋白IRS-1,P85,GLUT4降低,ERK1升高。由此表明:①此模型大鼠符合PCOS的诊断标准;②此模型大鼠存在卵巢局部胰岛素抵抗。     

电针对多囊卵巢综合征模型系统的调控

通过母体高雄环境建立子代雌性大鼠高雄激素血症和胰岛素抵抗模型,探讨针刺对孕期高雄化大鼠的治疗效果以及针刺调节卵巢局部胰岛素信号传导关键分子磷脂酰肌醇3激酶(PI-3K)和丝裂原激活蛋白激酶(MAPK),明确针刺治疗胰岛素抵抗的分子机制。在Wistar雌性大鼠颈背部皮下注射丙酸睾丸酮,连续3d。以其所生雌鼠作为实验对象,观察其体重及动情周期,检测血清性激素,17-羟孕酮(17-OHP)、雄烯二酮(A2)及OGTT试验测血糖、胰岛素水平,然后给予针刺治疗,观察其对生殖与代谢功能的影响。运用免疫组化及蛋白印迹方法,检测骨骼肌和卵巢组织中胰岛素受体底物-1(IRS-1)、胰岛素受体底物-2(IRS-2)、磷脂酰肌醇3-激酶(PI-3K85)、葡萄糖转运蛋白-4(GLUT4)、细胞外信号激酶-1(ERK-1)和17羟化酶(CYP17)蛋白表达。结果显示:①模型鼠无排卵,高雄、糖耐量减低,胰岛素抵抗;②针刺可以恢复动情周期,降低体重,降低LH、17-OHP、A2、T水平,升高E2水平;降低OGTT试验1h血糖水平,降低空腹和1h胰岛素水平,降低HOMA指数;③骨骼肌和卵巢局部产生胰岛素抵抗后,相应的IRS-1、IRS-2、PI-3K85和GLUT4的蛋白表达下降,ERK-1、CYP17的表达升高;针刺能逆转蛋白的异常表达。由此得出以下结论:①孕期注射丙酸睾丸酮,所生子代雌鼠有生殖和代谢异常,符合PCOS患者临床特征;②针刺能够降低雄激素,降低血糖,提高胰岛素敏感性,降低体重;③针刺能够调节模型动物骨骼肌和卵巢局部胰岛素信号传导蛋白表达和卵巢局部雄激素合成酶表达。