Latrunculin A delays anaphase onset in fission yeast by disrupting an ase1-independent pathway controlling mitotic spindle stability

It has been proposed previously that latrunculin A, an inhibitor of actin polymerization, delays the onset of anaphase by causing spindle misorientation in fission yeast. However, we show that {Delta}mto1 cells, which are defective in nucleation of cytoplasmic microtubules, have profoundly misoriented spindles but are not delayed in the timing of sister chromatid separation, providing compelling evidence that fission yeast does not possess a spindle orientation checkpoint. Instead, we show that latrunculin A delays anaphase onset by disrupting interpolar microtubule stability. This effect is abolished in a latrunculin A-insensitive actin mutant and exacerbated in cells lacking Ase1, which cross-links antiparallel interpolar microtubules at the spindle midzone both before and after anaphase. These data indicate that both Ase1 and an intact actin cytoskeleton are required for preanaphase spindle stability. Finally, we show that loss of Ase1 activates a checkpoint that requires only the Mad3, Bub1, and Mph1, but not Mad1, Mad2, or Bub3 checkpoint proteins

Accurate simulations of the interplay between process and statistical variability for nanoscale FinFET-based SRAM cell stability

In this paper we illustrate how by using advanced atomistic TCAD tools the interplay between long-range process variation and short-range statistical variability in FinFETs can be accurately modelled and simulated for the purposes of Design-Technology Co-Optimization (DTCO). The proposed statistical simulation and compact modelling methodology is demonstrated via a comprehensive evaluation of the impact of FinFET variability on SRAM cell stability

Data management of nanometre­ scale CMOS device simulations

In this paper we discuss the problems arising in managing and curating the data generated by simulations of nanometre scale CMOS (Complementary Metal–Oxide Semiconductor) transistors, circuits and systems and describe the software and operational techniques we have adopted to address them. Such simulations pose a number of challenges including, inter alia, multi­TByte data volumes, complex datasets with complex inter-relations between datasets, multi­-institutional collaborations including multiple specialisms and a mixture of academic and industrial partners, and demanding security requirements driven by commercial imperatives. This work was undertaken as part of the NanoCMOS project. However, the problems, solutions and experience seem likely to be of wider relevance, both within the CMOS design community and more generally in other disciplines

2D-TCAD Simulation on Retention Time of Z2FET for DRAM Application

Traditional memory devices are facing more challenges due to continuous down-scaling. 6T-SRAM suffers from variability [1-2] and reliability [3-4] issues, which introduce cell stability problems. DRAM cells with one transistor, one capacitor (1T1C) struggle to maintain refresh time [5-6]. Efforts have been made to find new memory solutions, such as one transistor (1T) solutions [7-9]. Floating body based memory structures are among the potential candidates, but impact ionization or band-to-band tunnelling (B2BT) limits their refresh time [10]. A recently proposed zero impact ionization and zero subthreshold swing device named Z2FET [9, 11-12] has been demonstrated and is a promising candidate for 1T DRAM memory cell due to technology advantages such as CMOS technology compatibility, novel capacitor-less structure and sharp switching characteristics. In the Z2FET memory operation, refresh frequency is determined by data retention time. Previous research [11-12] is lacking systematic simulation analysis and understanding on the underlying mechanisms. In this paper, we propose a new simulation methodology to accurately extract retention time in Z2FET devices and understand its dependency on applied biases, temperatures and relevant physical mechanisms. Since the stored ‘1’ state in Z2FET is an equilibrium state [9, 11-12] and there is no need to refresh, we will concentrate on state ‘0’ retention. Two types of ‘0’ retention time: HOLD ‘0’ and READ ‘0’ retention time will be discussed separately

Secure, performance-oriented data management for nanoCMOS electronics

The EPSRC pilot project Meeting the Design Challenges of nanoCMOS Electronics (nanoCMOS) is focused upon delivering a production level e-Infrastructure to meet the challenges facing the semiconductor industry in dealing with the next generation of ‘atomic-scale’ transistor devices. This scale means that previous assumptions on the uniformity of transistor devices in electronics circuit and systems design are no longer valid, and the industry as a whole must deal with variability throughout the design process. Infrastructures to tackle this problem must provide seamless access to very large HPC resources for computationally expensive simulation of statistic ensembles of microscopically varying physical devices, and manage the many hundreds of thousands of files and meta-data associated with these simulations. A key challenge in undertaking this is in protecting the intellectual property associated with the data, simulations and design process as a whole. In this paper we present the nanoCMOS infrastructure and outline an evaluation undertaken on the Storage Resource Broker (SRB) and the Andrew File System (AFS) considering in particular the extent that they meet the performance and security requirements of the nanoCMOS domain. We also describe how metadata management is supported and linked to simulations and results in a scalable and secure manner

The Effect of Carbon Dioxide on Nitrate Accumulation in Carrington Loam

Most microorganisms obtain carbon as well as energy from the oxidation of organic compounds but the nitrifying bacteria assimilate carbon dioxide from the air as a source of carbon. The sulfur bacteria and the hydrogen oxidizing bacteria also assimilate carbon dioxide from the air. Other bacteria that cannot assimilate carbon dioxide from the air are greatly stimulated by its presence. Increasing the concentration of carbon dioxide in the air about cultures of Lactobacillus acidophilus produces higher plate counts and larger colonies than cultures in carbon dioxide-free air. An increased concentration of carbon dioxide in the soil air stimulates the growth of certain of the fungi, particularly those associated with root-rot of the higher plants. Some of the fleshy fungi, the so-called lignin-destroying fungi, are greatly retarded in growth by the removal of carbon dioxide from the atmosphere in which they grow. On the other hand, there are cases on record in which carbon dioxide has acted as a growth depressant or germicide. The spores of Mucor, Aspergillus and Penicillium are prevented from germination by very high concentrations of carbon dioxide. The growth rate of yeast and fermentation of solutions have been retarded by certain concentrations of carbon dioxide