One-dimensional staged self-assembly

17th International Conference, DNA 17, Pasadena, CA, USA, September 19-23, 2011. ProceedingsWe introduce the problem of staged self-assembly of one-dimensional nanostructures, which becomes interesting when the elements are labeled (e.g., representing functional units that must be placed at specific locations). In a restricted model in which each operation has a single terminal assembly, we prove that assembling a given string of labels with the fewest stages is equivalent, up to constant factors, to compressing the string to be uniquely derived from the smallest possible context-free grammar (a well-studied O(logn)-approximable problem). Without this restriction, we show that the optimal assembly can be substantially smaller than the optimal context-free grammar, by a factor of Ω √n/log n even for binary strings of length n. Fortunately, we can bound this separation in model power by a quadratic function in the number of distinct glues or tiles allowed in the assembly, which is typically small in practice

Towards the “ultimate earthquake-proof” building: Development of an integrated low-damage system

The 2010–2011 Canterbury earthquake sequence has highlighted the severe mismatch between societal expectations over the reality of seismic performance of modern buildings. A paradigm shift in performance-based design criteria and objectives towards damage-control or low-damage design philosophy and technologies is urgently required. The increased awareness by the general public, tenants, building owners, territorial authorities as well as (re)insurers, of the severe socio-economic impacts of moderate-strong earthquakes in terms of damage/dollars/ downtime, has indeed stimulated and facilitated the wider acceptance and implementation of cost-efficient damage-control (or low-damage) technologies. The ‘bar’ has been raised significantly with the request to fast-track the development of what the wider general public would hope, and somehow expect, to live in, i.e. an “earthquake-proof” building system, capable of sustaining the shaking of a severe earthquake basically unscathed. The paper provides an overview of recent advances through extensive research, carried out at the University of Canterbury in the past decade towards the development of a low-damage building system as a whole, within an integrated performance-based framework, including the skeleton of the superstructure, the non-structural components and the interaction with the soil/foundation system. Examples of real on site-applications of such technology in New Zealand, using concrete, timber (engineered wood), steel or a combination of these materials, and featuring some of the latest innovative technical solutions developed in the laboratory are presented as examples of successful transfer of performance-based seismic design approach and advanced technology from theory to practice

Slotted Reinforced Concrete Beam-Column Connection: State-of-the-Art Review

Research on reinforced concrete (RC) beam-column connections has significantly increased during the past few decades. Interest in this topic is related to the importance of beam-column connections in maintaining the integrity of the whole structure. The slotted RC beam-column connection was investigated as promising low damage beam-column connection replacement for conventional design. A slotted RC beam consists of a conventional RC beam, modified with a narrow vertical slot adjacent to the face of the column that runs approximately three-quarters of the beam depth. This study reviews the literature on the mechanics and design of slotted beams, illustrating the works of various researchers on developing and modifying this innovative system. Then, the research progress in the behavior of slotted RC beams is briefly described, in chronological order, to place each contribution in a wider context. Extremely promising structural performance was observed due to minimum beam elongation, non-tearing action, minimum cracks, high energy dissipation, and stable hysteresis response. At the end of the study, a list of the main gaps that need further investigation and recommendations to fill out these gaps are provided

Producibility in hierarchical self-assembly

Three results are shown on producibility in the hierarchical model of tile self-assembly. It is shown that a simple greedy polynomial-time strategy decides whether an assembly α is producible. The algorithm can be optimized to use O(|α|log^2 |α|) time. Cannon et al. (STACS 2013: proceedings of the thirtieth international symposium on theoretical aspects of computer science. pp 172–184, 2013) showed that the problem of deciding if an assembly α is the unique producible terminal assembly of a tile system T can be solved in O(|α|^2 |T|+|α||T|^2) time for the special case of noncooperative “temperature 1” systems. It is shown that this can be improved to O(|α||T|log|T|) time. Finally, it is shown that if two assemblies are producible, and if they can be overlapped consistently—i.e., if the positions that they share have the same tile type in each assembly—then their union is also producible

Integration of Nanostructures into Microsensor Devices on Whole Wafers

Chemical sensors are used in a wide variety of applications, such as environmental monitoring, fire detection, emission monitoring, and health monitoring. The fabrication of chemical sensors involving nanostructured materials holds the potential for the development of sensor systems with unique properties and improved performance. However, the fabrication and processing of nanostructures for sensor applications currently are limited in the ability to control their location on the sensor, which in turn hinders the progress for batch fabrication. This report discusses the advantages of using nanomaterials in sensor designs, some of the challenges encountered with the integration of nanostructures into microsensor / devices, and then briefly describes different methods attempted by other groups to address this issue. Finally, this report will describe how our approach for the controlled alignment of nanostructures onto a sensor platform was applied to demonstrate an approach for the mass production of sensors with nanostructures

Functional segmentation of CoQ and cyt c pools by respiratory complex superassembly.

Electron transfer between respiratory complexes is an essential step for the efficiency of the mitochondrial oxidative phosphorylation. Until recently, it was stablished that ubiquinone and cytochrome c formed homogenous single pools in the inner mitochondrial membrane which were not influenced by the presence of respiratory supercomplexes. However, this idea was challenged by the fact that bottlenecks in electron transfer appeared after disruption of supercomplexes into their individual complexes. The postulation of the plasticity model embraced all these observations and concluded that complexes and supercomplexes co-exist and are dedicated to a spectrum of metabolic requirements. Here, we review the involvement of superassembly in complex I stability, the role of supercomplexes in ROS production and the segmentation of the CoQ and cyt c pools, together with their involvement in signaling and disease. Taking apparently conflicting literature we have built up a comprehensive model for the segmentation of CoQ and cyt c mediated by supercomplexes, discuss the current limitations and provide a prospect of the current knowledge in the field.S

Generation of Reactive Oxygen Species by Mitochondria.

Reactive oxygen species (ROS) are series of chemical products originated from one or several electron reductions of oxygen. ROS are involved in physiology and disease and can also be both cause and consequence of many biological scenarios. Mitochondria are the main source of ROS in the cell and, particularly, the enzymes in the electron transport chain are the major contributors to this phenomenon. Here, we comprehensively review the modes by which ROS are produced by mitochondria at a molecular level of detail, discuss recent advances in the field involving signalling and disease, and the involvement of supercomplexes in these mechanisms. Given the importance of mitochondrial ROS, we also provide a schematic guide aimed to help in deciphering the mechanisms involved in their production in a variety of physiological and pathological settings.This study was supported by MINECO: SAF2015-65633-R, RTI2018-099357-B-I00, HFSP (RGP0016/2018) and CIBER (CB16/10/00282). The CNIC is supported by the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia, Innovación y Universidades (MCNU) and the Pro CNIC Foundation and is a Severo Ochoa Center of Excellence (SEV-2015-0505). His research has been financed by Spanish Government grants (ISCIII and AEI agencies, partially funded by the European Union FEDER/ERDF)S

Seismic performance of the slotted beam detail in reinforced concrete moment resisting frames.

During recent seismic events, traditional reinforced concrete structures that have been shown to have performed as designed have had to be demolished due to prohibitive rehabilitation costs. The main contributors to rehabilitation costs were residual building inclination and damage to the structural system. In traditional reinforced concrete moment frames, this damage has been shown to be attributable either directly, or indirectly, to the formation of plastic hinge zones and the undesirable behaviour that can result. This research investigated and developed the reinforced concrete slotted beam as a means to increase the performance and safety of reinforced concrete moment frames during an earthquake. The slotted beam can significantly decrease damage sustained to the frame and floor of a building, while maintaining current build costs. The objective of this research was to develop the reinforced concrete slotted beam detail to a state in which it was ready for use by the New Zealand construction industry. To achieve this objective, many aspects of reinforced concrete slotted beam design, construction and performance were investigated. Existing design recommendations developed by previous researchers were examined through the design of a realistic large scale superassembly. Based on the results and observations of the experiment, design recommendations were modified and developed. The superassembly was subjected to full biaxial seismic displacements to investigate complex three-dimensional interactions between structural elements within a building typology representative of New Zealand construction. The practicality of the design, manufacture and erection of the reinforced concrete slotted beam detail was examined through the involvement of industry to construct the superassembly. The lessons learnt throughout the design and construction process were used to develop recommendations, which aimed to expedite the specification of the reinforced concrete slotted beam detail. Well-detailed traditional reinforced concrete structures have had to be demolished following earthquakes due to concerns regarding the residual capacity of the connections. The slotted beam detail increases the plastic strain in the bottom longitudinal reinforcement. Hence, the residual capacity of the slotted beam following a seismic event was examined. Portions of superassembly SA1 were extracted and tested to determine the effect that previous loading had on both performance and reliability. An economically viable method for retrofitting the slotted beam was developed to decrease the life-cycle costs of a slotted beam building by preventing the necessity for demolition after a major earthquake if it were deemed that the residual capacity was not great enough, or not known with sufficient certainty. Recommendations for the design and implementation of a retrofit scheme for the slotted beam were developed. Preventing the need to retrofit slotted beam connections following an earthquake is preferable. Hence, external dampers that were either easily replaceable or could withstand multiple earthquakes were tested for both retrofit and new-build applications. A structure that exhibits reduced damage during an earthquake, returns to plumb and requires little repair prior to reoccupation is the goal of seismic building design. This can be achieved using the slotted beam detail in conjunction with external energy dissipation devices. Given the rise in the popularity of numerical models for both research and design, it was important to develop a numerical model that was not only capable of reproducing realistic slotted beam behaviour in three dimensions, but could be quickly set up using only gross section and material properties. The new numerical model was verified against experimental data before being used to compare both connection and structural responses of slotted beam and traditional systems

Cooling of LED luminaires

Tässä työssä tutustutaan LED-valaisinten jäähdytyssuunnittelun teoriaan sekä erilaisiin käytännön jäähdytysmenetelmiin. Työssä esitellään LED-komponenttien toimintaa ja lämpenemisen syitä ja seurauksia sekä käydään läpi lämmönsiirron teoriaa. Lisäksi käydään läpi, miten eri valaisimen osat vaikuttavat valaisimen jäähdytykseen. Työssä kartoitetaan myös, millaisia jäähdytyslaiteratkaisuja elektroniikkalaitteiden jäähdytykseen on käytetty, miten ne toimivat ja mitä eroja eri laitteiden välillä on. Työn lopussa käydään läpi LED-valaisimen lämpöresistanssiverkon laskentaa ja esitetään vaihtoehtoja kevytliikenneväylän valaistukseen tarkoitetun LED-valaisimen jäähdyttämiseksi.This thesis presents the theory and practice of LED luminaire cooling. The operational principles of LEDs will be introduced along with causes and effects of temperature rise in LED components. The work also introduces the basics of heat transfer theory. The effects of individual luminaire parts on heat transfer will be analysed. Different kinds of cooling equipment and their operational principles and differences will be studied. An exemplary analysis of cooling options, heat transfer and the heat resistance network of an LED luminaire for pedestrian road lighting will also be explored