From the history of low temperature physics: Prejudicial attitudes that hindered the initial development of superconductivity theory

In this paper we primarily study the difficulties in the application of the thermodynamical approach to the phenomenon of superconductivity, resulting from a specific interpretation of the low temperature behavior of the Maxwell equations. An attempt is made to elucidate the situation during the first period of the development of superconductivity theory and to render explicit prejudiced attitudes reminiscent of Feyerabend's natural interpretations.     

Amplification of a gene encoding a p53-associated protein in human sarcomas.

Despite extensive data linking mutations in the p53 gene to human tumorigenesis, little is known about the cellular regulators and mediators of p53 function. MDM2 is a strong candidate for one such cellular protein; the MDM2 gene was originally identified by virtue of its amplification in a spontaneously transformed derivative of mouse BALB/c cells and the MDM2 protein subsequently shown to bind to p53 in rat cells transfected with p53 genes. To determine whether MDM2 plays a role in human cancer, we have cloned the human MDM2 gene. Here we show that recombinant-derived human MDM2 protein binds human p53 in vitro, and we use MDM2 clones to localize the human MDM2 gene to chromosome 12q13-14. Because this chromosomal position appears to be altered in many sarcomas, we looked for changes in human MDM2 in such cancers. The gene was amplified in over a third of 47 sarcomas, including common bone and soft tissue forms. These results are consistent with the hypothesis that MDM2 binds to p53, and that amplification of MDM2 in sarcomas leads to escape from p53-regulated growth control. This mechanism of tumorigenesis parallels that for virally-induced tumours, in which viral oncogene products bind to and functionally inactivate p53.     

The motion of the moon in the Romaka Siddhānta

Summary Formulae are fitted to the different sets of values, given by the translators, for the equation of centre for the motion of the moon according to the Romaka Siddhnta, as found in the Pañcasiddhntik of Varha Mihira.     

设计及自组装六边形网格状DNA二维阵列

根据Watson-Crick DNA碱基互补配对原则,设计了不同黏性末端DNA序列,以两种三点星状为模块(three-point-star motif),运用DNA自组装技术,成功制备了六边形网格状DNA二维阵列.研究不同单链DNA的摩尔比例对三点星状模块结构组装的影响,以及不同起始退火温度对二维阵列自组装的影响,用凝胶电泳及原子力显微镜(AFM)对结构进行了表征.结果表明,当构成三点星状模块的3条单链摩尔比例为1:3:3时得到的模块结构更稳定,从50℃开始退火时得到的二维阵列更完整.自组装得到的二维阵列厚度约2nm,六边形边长约20nm.本研究为进一步探究三点星模块组装二维阵列的机理提供了新的思路.     

Genome-wide association scan identifies a colorectal cancer susceptibility locus on chromosome 8q24

Using a multistage genetic association approach comprising 7,480 affected individuals and 7,779 controls, we identified markers in chromosomal region 8q24 associated with colorectal cancer. In stage 1, we genotyped 99,632 SNPs in 1,257 affected individuals and 1,336 controls from Ontario. In stages 2-4, we performed serial replication studies using 4,024 affected individuals and 4,042 controls from Seattle, Newfoundland and Scotland. We identified one locus on chromosome 8q24 and another on 9p24 having combined odds ratios (OR) for stages 1-4 of 1.18 (trend; P = 1.41 x 10(-8)) and 1.14 (trend; P = 1.32 x 10(-5)), respectively. Additional analyses in 2,199 affected individuals and 2,401 controls from France and Europe supported the association at the 8q24 locus (OR = 1.16, trend; 95% confidence interval (c.i.): 1.07-1.26; P = 5.05 x 10(-4)). A summary across all seven studies at the 8q24 locus was highly significant (OR = 1.17, c.i.: 1.12-1.23; P = 3.16 x 10(-11)). This locus has also been implicated in prostate cancer.     

Amygdala intercalated neurons are required for expression of fear extinction

Congruent findings from studies of fear learning in animals and humans indicate that research on the circuits mediating fear constitutes our best hope of understanding human anxiety disorders. In mammals, repeated presentations of a conditioned stimulus that was previously paired to a noxious stimulus leads to the gradual disappearance of conditioned fear responses. Although much evidence suggests that this extinction process depends on plastic events in the amygdala, the underlying mechanisms remain unclear. Intercalated (ITC) amygdala neurons constitute probable mediators of extinction because they receive information about the conditioned stimulus from the basolateral amygdala (BLA), and contribute inhibitory projections to the central nucleus (CEA), the main output station of the amygdala for conditioned fear responses. Thus, after extinction training, ITC cells could reduce the impact of conditioned-stimulus-related BLA inputs to the CEA by means of feed-forward inhibition. Here we test the hypothesis that ITC neurons mediate extinction by lesioning them with a toxin that selectively targets cells expressing micro-opioid receptors (microORs). Electron microscopic observations revealed that the incidence of microOR-immunoreactive synapses is much higher in ITC cell clusters than in the BLA or CEA and that microORs typically have a post-synaptic location in ITC cells. In keeping with this, bilateral infusions of the microOR agonist dermorphin conjugated to the toxin saporin in the vicinity of ITC neurons caused a 34% reduction in the number of ITC cells but no significant cell loss in surrounding nuclei. Moreover, ITC lesions caused a marked deficit in the expression of extinction that correlated negatively with the number of surviving ITC neurons but not CEA cells. Because ITC cells exhibit an unusual pattern of receptor expression, these findings open new avenues for the treatment of anxiety disorders.     

3D DNA origami designed with caDNAno

For about three decades, DNA-based nanotechnology has been undergoing development as an assembly method for nanostructured materials. The DNA origami method pioneered by Rothemund paved the way for the formation of 3D structures using DNA self assembly. The origami approach uses a long scaffold strand as the input for the self assembly of a few hundred staple strands into desired shapes. Herein, we present a 3D origami "roller" (75 nm in length) designed using caDNAno software. This has the potential to be used as a template to assemble nanoparticles into different pre-defined shapes. The "roller" was characterized with agarose gel electrophoresis, atomic force microscopy (AFM) and transmission electron microscopy (TEM).     

Environmental and energy gains from using molten magnesium–sodium–potassium chlorides for electro-metallisation of refractory metal oxides

The molten eutectic mixture of magnesium,sodium and potassium chlorides(Mg Cl2–Na Cl–KCl) has inappreciable solubility for oxide ions,and can help disengage a carbon anode from the oxide ions generated at a metal oxide cathode,and effectively avoid carbon dioxide formation.This "disengaging strategy" was successfully demonstrated in electro-reduction of solid oxides of zirconium and tantalum.It has led to significantly higher current efficiency(93%),and lower energy consumption(1.4 k W h kg 1) in electrolysis of tantalum oxide to tantalum metal compared to the conventional electrolysis in molten calcium chloride(e.g.78% and 2.4 k W h/kg-Ta).