Alternative Interface Research Articles

Redesign of the monomer-monomer interface of Cre recombinase yields an obligate heterotetrameric complex.

Cre recombinase catalyzes the cleavage and religation of DNA at loxP sites. The enzyme is a homotetramer in its functional state, and the symmetry of the protein complex enforces a pseudo-palindromic symmetry upon the loxP sequence. The Cre-lox system is a powerful tool for many researchers. However, broader application of the system is limited by the fixed sequence preferences of Cre, which are determined by both the direct DNA contacts and the homotetrameric arrangement of the Cre monomers. As a first step toward achieving recombination at arbitrary asymmetric target sites, we have broken the symmetry of the Cre tetramer assembly. Using a combination of computational and rational protein design, we have engineered an alternative interface between Cre monomers that is functional yet incompatible with the wild-type interface. Wild-type and engineered interface halves can be mixed to create two distinct Cre mutants, neither of which are functional in isolation, but which can form an active heterotetramer when combined. When these distinct mutants possess different DNA specificities, control over complex assembly directly discourages recombination at unwanted half-site combinations, enhancing the specificity of asymmetric site recombination. The engineered Cre mutants exhibit this assembly pattern in a variety of contexts, including mammalian cells.

Can VoiceScapes Assist in Menu Navigation?

Providing better information access to blind users is an important goal in the context of accessible interface design. Similarly, designers of user interfaces benefit from alternative interface techniques for usage scenarios in which visual (graphical) interfaces are either not possible or suboptimal. In our study we compared a traditional serial aural presentation of menu items to a new simultaneous aural presentation of up to seven menu items. These continuously present VoiceScapes allow the user to actively scan the auditory display to find the most appropriate command. While VoiceScapes are more difficult and attentionally more demanding than other formats of presentation, extended use might allow experienced users to more efficiently navigate complex menu hierarchies. A first pilot experiment with 13 sighted participants presented here tested the basic viability of this approach.

Social media platforms as educational interfaces - considering the way forward for blended learning

Despite their pervasiveness, Virtual Learning Environments (VLEs) are subject to a number of criticisms of their efficacy as platforms for blended learning (Weller, 2006). This paper considers the use of social media platform Padlet as an alternative educational interface through evaluation of an intervention-based case-study. Focus groups were conducted with the student cohort, identifying a number of recurring themes that form the main body of this paper: visuality and clarity of the interface, autonomy over learning, students as co-producers and critical reflection. These themes address the intervention itself, and acknowledge the limitations of the research by proposing potential developments. The paper concludes by drawing together questions for further research, and notably reflects on whether it is more pertinent to address the way we use educational interfaces, rather than the interfaces themselves, in considering ‘the way forward’ for blended learning in Higher Education 2018.

Observation of interface dependent spin polarized photocurrents in InAs/GaSb superlattice

In this letter, we investigated the spin polarized photocurrents excited by mid-infrared radiation and near-infrared radiation, respectively, in InAs/GaSb type II superlattices with different kinds of interfaces. By periodically varying the polarization state of the radiation, we analyzed Rashba-type and Dresselhaus-type spin polarized photocurrents, which present different features depending on the interface types and excitation conditions. Under mid-infrared excitation, the ratio of Rashba-type and Dresselhaus-type spin polarized photocurrents of the superlattice with InSb-like interface is obviously larger than that of the superlattice with GaAs-like interface, the ratio of the superlattice with alternate interface is in the middle. Whereas under near-infrared excitation, the ratios of the three superlattices are nearly the same. Further researches reveal the synactic effects of interface dependent strain and asymmetric interface potential on the spin splitting. Besides, the polarized Raman spectroscopies of these structures were also analyzed.

Crystal Structure of Fad35R from Mycobacterium tuberculosis H37Rv in the Apo-State.

Fad35R from Mycobacterium tuberculosis binds to the promoter site of Fad35 operon and its DNA binding activities are reduced in the presence of tetracycline and palmitoyl-CoA. We resolved the crystal structure of Fad35R using single-wavelength anomalous diffraction method (SAD). Fad35R comprises canonical DNA binding domain (DBD) and ligand binding domain (LBD), but displays several distinct structural features. Two recognition helices of two monomers in the homodimer are separated by ~ 48 Å and two core triangle-shaped ligand binding cavities are well exposed to solvent. Structural comparison with DesT and QacR structures suggests that ligand binding-induced movement of α7, which adopts a straight conformation in the Fad35R, may be crucial to switch the conformational states between repressive and derepressive forms. Two DBDs are packed asymmetrically, creating an alternative dimer interface which coincides with the possible tetramer interface that connects the two canonical dimers. Quaternary state of alternative dimer mimics a closed-state structure in which two recognition helices are distanced at ~ 35 Å and ligand binding pockets are inaccessible. Results of biophysical studies indicate that Fad35R has the propensity to oligomerize in solution in the presence of tetracycline. We present the first structure of a FadR homologue from mycobacterium and the structure reveals DNA and ligand binding features of Fad35R and also provides a view on alternative quaternary states that mimic open and closed forms of the regulator.

Analysis, control and experimental verification of a single‐phase capacitive‐coupling grid‐connected inverter

This study proposes a capacitive-coupling grid-connected inverter (CGCI), which consists of a full-bridge single-phase inverter coupled to a power grid via one capacitor in series with an inductor. The fundamental-frequency impedance of the coupling branch is capacitive. In contrast with the conventional inductive-coupling grid-connected inverter (IGCI), this structure provides an alternative interface for use between a low-voltage DC microgrid and an AC grid. A comparison between the CGCI and the IGCI is performed. It is concluded that the CGCI is able to transfer active power and provide lagging reactive power at an operational voltage much lower than that of the IGCI. This reduces the system's initial cost and operational losses, as well as the energy stored in the DC-link capacitor. The CGCI has been analysed and a DC voltage selection method is proposed. Using this method, the DC-link voltage of the CGCI remains at approximately of 50% of the peak grid voltage. In addition, a P-unit current controller is proposed for use with the CGCI, as a proportional–integral controller is not suitable. Finally, simulation and experiments show the effectiveness of the proposed approach.

Assistive Device With Conventional, Alternative, and Brain-Computer Interface Inputs to Enhance Interaction With the Environment for People With Amyotrophic Lateral Sclerosis: A Feasibility and Usability Study

ObjectiveTo evaluate the feasibility and usability of an assistive technology (AT) prototype designed to be operated with conventional/alternative input channels and a P300-based brain-computer interface (BCI) in order to provide users who have different degrees of muscular impairment resulting from amyotrophic lateral sclerosis (ALS) with communication and environmental control applications. DesignProof-of-principle study with a convenience sample. SettingAn apartment-like space designed to be fully accessible by people with motor disabilities for occupational therapy, placed in a neurologic rehabilitation hospital. ParticipantsEnd-users with ALS (N=8; 5 men, 3 women; mean age ± SD, 60±12y) recruited by a clinical team from an ALS center. InterventionsThree experimental conditions based on (1) a widely validated P300-based BCI alone; (2) the AT prototype operated by a conventional/alternative input device tailored to the specific end-user's residual motor abilities; and (3) the AT prototype accessed by a P300-based BCI. These 3 conditions were presented to all participants in 3 different sessions. Main Outcome MeasuresSystem usability was evaluated in terms of effectiveness (accuracy), efficiency (written symbol rate, time for correct selection, workload), and end-user satisfaction (overall satisfaction) domains. A comparison of the data collected in the 3 conditions was performed. ResultsEffectiveness and end-user satisfaction did not significantly differ among the 3 experimental conditions. Condition III was less efficient than condition II as expressed by the longer time for correct selection. ConclusionsA BCI can be used as an input channel to access an AT by persons with ALS, with no significant reduction of usability.

Validation of “alarm bar” alternative interface for digital control panel design: A preliminary experimental study

Properly designed alarm systems can benefit operators in conducting routine and emergency tasks. With the digitization of main control rooms, the alarm interface can be designed in various ways that are different from the traditional “alarm tile” style. An innovative alarm bar interface is proposed in this paper. A preliminary lab experiment was conducted to compare the traditional alarm tile and the new alarm bar interfaces. Sixteen university students were recruited to participate in the experiment, in which two emergency scenarios, Loss of Coolant Accident and Steam Generator Tube Rupture, were tested. The experiment task included two parts: alarm detection and identification. The subjective ratings supported the innovative alarm bar design for better parameter trend perception. The objective performance measures showed that the simpler design of the alarm tile interface better aided the alarm detection performance, whereas the alarm bar interface had almost the same alarm identification performance as the alarm tile interface. Relevance to industryAn alarm system is critical for a complex industrial system. The experimental results show that design evaluation is more complex than it may seem. Although it has not been proved to be overwhelmingly superior to the tile design, the alarm bar design shows promise for aiding operators and needs to be further validated.

A 3D Visual Interface for Critiquing-based Recommenders: Architecture and Interaction

Nowadays e-commerce websites offer users such a huge amount of products, which far from facilitating the buying process, actually make it more difficult. Hence, recommenders, which learn from users' preferences, are consolidating as valuable instruments to enhance the buying process in the 2D Web. Indeed, 3D virtual environments are an alternative interface for recommenders. They provide the user with an immersive 3D social experience, enabling a richer visualisation and increasing the interaction possibilities with other users and with the recommender. In this paper, we focus on a novel framework to tightly integrate interactive recommendation systems in a 3D virtual environment. Specifically, we propose to integrate a Collaborative Conversational Recommender (CCR) in a 3D social virtual world. Our CCR Framework defines three layers: the user interaction layer (3D Collaborative Space Client), the communication layer (3D Collaborative Space Server), and the recommendation layer (Collaborative Conversational Recommender). Additionally, we evaluate the framework based on several usability criteria such as learnability, perceived efficiency and effectiveness. Results demonstrate that users positively valued the experience.

Communication Method of Time Synchronization and Strength Using Haptic Interface

<div class=""abs_img""><img src=""[disp_template_path]/JRM/abst-image/00260006/10.jpg"" width=""300"" />Electric music baton system</div> We are developing an electronic baton system as an alternative haptic interface to facilitate music lessons for the visually impaired. This system incorporates an acceleration sensor in the baton, transmits data to a player via radio signals, and acts as a haptic interface by generating vibrations. In this paper, we experimentally evaluate responses to the stimulus of the visual and the tactile senses in order to verify that a haptic interface can substitute for vision in scenarios that involve real-time tasks, such as music lessons. In the first experiment, we verify that clue motions are important for both the visual and a tactile senses. Next, we test the new method of communicating strength. Thismethod uses not vibration strength but oscillating time for vibrations of the haptic device. The results of the experiment confirm that the technique is effective. </span>

Charge compensation phenomena for polarization discontinuities in ferroelectric superlattices

Based on the Landau-Ginzburg theory, the screening charge compensation phenomena for polarization discontinuities at interface in ferroelectric superlattices are investigated. Interface mixing leads to polarization continuity or discontinuity in superlattices. Free charge with equal but of opposite sign for alternate interface, driven by internal electric field, builds up to counteract the depolarization effect in superlattices. The charge density depends on the degree of interface mixing, and it approaches a saturated value when the mismatch of internal field or polarization at interface vanishes. Using PbTiO3/SrTiO3 (PT/ST) as a model system, the charge compensation phenomena for polarization discontinuities in superlattices is investigated by examining the polarization and internal electric field profiles. Dependence of local polarization and internal field at the interfaces on screening charge density is also examined in detail.

Assessment of Alternative Interfaces for Manual Commanding of Spacecraft Systems

Astronauts will be responsible for executing a much larger body of procedures as human exploration moves further from Earth and Mission Control. Efficient, reliable methods for executing these procedures, including manual, automated, and mixed execution will be important. We evaluated a new procedure system that integrates step-by-step instruction with the means for execution. While the system allows automation, the critical first step, investigated here, is effectiveness supporting manual execution. We compared manual execution using the new system to a system analogous to the manual-only system currently in use on the International Space Station; we assessed whether manual performance with the new system would be as good or better than with the legacy system. This lays the foundation for integrating automated execution into the flow of procedures designed for humans. In our formative study, we found speed and accuracy of procedure execution was better using the new, integrated interface over the legacy design.

Polymer-Based Micro Flow Sensor with Alternative Electronic Signal Interfaces for Low and High Flow Rates

Polymer-Based Micro Flow Sensor with Alternative Electronic Signal Interfaces for Low and High Flow Rates

Ushering the Cactvs Toolkit into the Python Age (without breaking the legacy)

The Cactvs Chemoinformatics Toolkit is probably the most powerful general-purpose chemical information processing toolkit on the market. Since its inception about twenty years ago, its main language for rapid script development has been Tcl – at that time a language at the forefront of lazily-typed rapid prototyping and interface programming language design. While Tcl is still actively maintained, and does provide features not matched by many of the nowadays more popular competitors – most notably impressive multi-threading capabilities, which are fully accessible from within the toolkit – history has passed on. Tcl has undeniably fallen out of the public eye, and there is an understandable reluctance by users to learn new languages which are effectively only used by one of their tools. This problem has finally been addressed. The Cactvs toolkit is now available with Python as a second alternative (or parallel) interface language. The new interface closely follows the established Tcl command patterns to support easy migration by experienced users, while still providing true “pythonesque” constructs. Since significant functionality of the toolkit is implemented as external Tcl script function snippets, and future enhancements will probably preferably be coded in Python without providing also a Tcl port, providing automatic and fully transparent access to language-mismatched components has been an important and rather peculiar design goal. Examples of the new toolkit scripting capabilities shall be presented, as well as a documentation of the challenges involved in the design of a parallel multi-language interface to a large software system.

On‐chip readout circuit for nanomagnetic logic

An interface for reading the output of nanomagnetic logic (NML) is indispensable in order for NML to interact with existing CMOS ICs. Two alternative designs readout interface circuit (RIC1 and RIC2) for NML RIC are proposed based on dual barriers magnetic tunnel junction (DBs-MTJ), which is composed of two fixed layers (with anti-parallel magnetisation state) and a common free layer. RIC1 utilises the same layer order of DB-MTJ to form an up–down structure, whereas RIC2 exploits the reversed layer order of DB-MTJ to form a left–right structure. They utilise the three-terminal approach to realise the self-reference readout scheme. The magnetisation state of the free layers in RIC1 and RIC2 are controlled by the fringing field from NML and biased by the designed on-chip clock field. The sensing circuits in RIC1 and RIC2 utilise dynamic current mode and pre-charge sense amplifier, respectively. The simulation results indicate that RIC1 and RIC2 can achieve comparable magnetoresistance values, and also realise the logical readout scheme by itself. The switching time in RIC1 is less than that in RIC2, whereas time delay for data transportation in RIC1 is more than that in RIC2. RIC2 is more amenable than RIC1 to the current fabrication process technology.

Investigation of shock-driven dry friction between stainless steel and aluminum alloy

Previous researchers studied dynamic friction by using an impacting copper plate to drive a tapered aluminum alloy 5083-H111 cone into a matching recess in a stainless steel outer retainer. The velocity of the rear surface of the cone was measured using velocity interferometry. We have performed experiments on a version of this configuration that has been enlarged so that the sliding surfaces remain in contact for a longer time than with the original configuration. As in the earlier work, the velocity on the axis of the rear surface of the inner cone was measured. In addition, the inner aluminum cones were recovered after the experiment and sectioned and etched. This provided an additional diagnostic for comparison with simulation. Simulations were run using a Lagrangian code with three alternative interface treatments: free sliding, rigidly locked (bonded), and a physics-based friction (PBF) model, details of which are presented. The work clearly indicated that the frictional forces could not be modelled by a freely sliding interface. The best match to the experiments was obtained by modelling the interface using the PBF model in conjunction with an initial gap of a few microns between the cone and outer retainer interface. This treatment reproduced the measured grain structures in the recovered experimental components and also captured many of the features of the observed velocity profiles.

Structure of FGFR3 Transmembrane Domain Dimer: Implications for Signaling and Human Pathologies

Fibroblast growth factor receptor 3 (FGFR3) transduces biochemical signals via lateral dimerization in the plasma membrane, and plays an important role in human development and disease. Eight different pathogenic mutations, implicated in cancers and growth disorders, have been identified in the FGFR3 transmembrane segment. Here, we describe the dimerization of the FGFR3 transmembrane domain in membrane-mimicking DPC/SDS (9/1) micelles. In the solved NMR structure, the two transmembrane helices pack into a symmetric left-handed dimer, with intermolecular stacking interactions occurring in the dimer central region. Some pathogenic mutations fall within the helix-helix interface, whereas others are located within a putative alternative interface. This implies that although the observed dimer structure is important for FGFR3 signaling, the mechanism of FGFR3-mediated transduction across the membrane is complex. We propose an FGFR3 signaling mechanism that is based on the solved structure, available structures of isolated soluble FGFR domains, and published biochemical and biophysical data.

Spectral methods based on new formulations for coupled Stokes and Darcy equations

In this paper we consider the numerical solution of the Stokes and Darcy coupled equations, which frequently appears in porous media modeling. The main contribution of this work is as follows: First, we introduce a new formulation for the Stokes/Darcy coupled equations, subject respectively to the Beavers–Joseph–Saffman interface condition and an alternative matching interface condition. Secondly, we prove the well-posedness of these weak problems by using the classical saddle point theory. Thirdly, some spectral approximations to the weak problems are proposed and analyzed, and some error estimates are provided. It is found that the new formulations significantly simplify the error analysis and numerical implementation. Finally, some two-dimensional spectral and spectral element numerical examples are provided to demonstrate the efficiency of our methods.

Mask Versus Nasal Tube for Stabilization of Preterm Infants at Birth: A Randomized Controlled Trial

Positive-pressure ventilation (PPV) using a manual ventilation device and a face mask is recommended for compromised newborn infants in the delivery room (DR). Mask ventilation is associated with airway obstruction and leak. A nasal tube is an alternative interface, but its safety and efficacy have not been tested in extremely preterm infants. An unblinded randomized controlled trial was conducted in Australia, and the Netherlands. Infants were stratified by gestational age (24-25/26-29 weeks) and center. Immediately before birth infants were randomly assigned to receive PPV and/or continuous positive airway pressure with either a nasal tube or a size 00 soft, round silicone mask. Resuscitation protocols were standardized; respiratory support was provided using a T-piece device commencing in room air. Criteria for intubation included need for cardiac compressions, apnea, continuous positive airway pressure >7 cm H2O, and fraction of inspired oxygen >0.4. Primary outcome was endotracheal intubation in the first 24 hours from birth. Three hundred sixty-three infants were randomly assigned; the study terminated early on the grounds of futility. Baseline variables were similar between groups. Intubation rates in the first 24 hours were 54% and 55% in the nasal tube and face mask groups, respectively (odds ratio: 0.97; 95% confidence interval: 0.63-1.50). There were no important differences in any of the secondary outcomes within the whole cohort or between the 2 gestational age subgroups. In infants at <30 weeks' gestation receiving PPV in the DR, there were no differences in short-term outcomes using the nasal tube compared with the face mask.

Symmetrically abrupt GaN/AlGaN superlattices by alternative interface–interruption scheme – ERRATUM

Symmetrically abrupt GaN/AlGaN superlattices by alternative interface–interruption scheme – <b>ERRATUM</b>