NavMol 2.0 – A Molecular Structure Navigator/Editor for Blind and Visually Impaired Users

This paper presents an assistive system that enables blind and visually impaired (BVI) users to localize and reach objects using spatialized audio cues, rendered as if the objects themselves emit sound. By integrating voice command recognition, RGB-D-based 3D localization, and head-tracked spatial audio via Apple AirPods Pro, the system transforms object positions into egocentric, directional prompts aligned with the user’s head orientation. We evaluated the system through tabletop localization-to-contact tasks with blindfolded sighted participants, comparing a spatial-audio (SA) condition against a speech-only (SO) baseline. While success rates were comparable between conditions, spatial audio significantly reduced task completion time and subjective workload and received substantially higher usability ratings. These findings suggest that spatialized object-originating sound can enhance task efficiency and user experience in near-field, non-visual interaction scenarios.

This article examines the tools and techniques currently available that enable blind and visually impaired (BVI) individuals to visualize three-dimensional objects used in learning chemistry concepts. How BVI individuals engage with and visualize molecular structure is discussed and recent tactile (or haptic) and auditory methods for visualization of various chemistry concepts are summarized. Remaining challenges for chemistry education researchers are described with the aim of highlighting the potential value of educational research in further enabling BVI students to pursue careers in science, technology, engineering, and mathematics (STEM) fields.

Mobile health (mHealth) applications (apps) are crucial in delivering health information and services to older adults. Despite their importance, blind and visually impaired (BVI) older individuals often face significant challenges in app accessibility and usability. This study delves into the design preferences and expectations of BVI older users and underscores the necessity of user-centered design for inclusive mHealth apps. Conducted in September 2023, the study comprised six focus group interviews. Each session involved two to four participants who began with self-introductions, followed by discussions centered on three open-ended interview questions. The study involved 14 participants: four with severe low vision and 10 totally blind. The primary design principles highlighted were "customizability" and "simplicity". The participants stressed the importance of intuitively designed main pages aligning with user patterns. Further, the participants articulated the following mHealth app feature or menu recommendations: editable profiles, emergency contact access, adaptable data presentation, data exportation, audible color details, customizable colors for varying visual needs, audible error feedback, feasible data input methods, toolbars, and habit-establishing reminders. Discussions also touched on the vital role of clear health data visualizations and comprehensible app-based health information. The findings illuminate paths for software developers and health scientists working towards more inclusive mHealth solutions. It is essential during the development phase to prioritize app learnability to accommodate a broad range of users, ensuring that even those with disabilities can effectively use technological innovations to address health disparities.

Touchscreen-based smart devices, such as smartphones and tablets, offer great promise for providing blind and visually-impaired (BVI) users with a means for accessing graphics non-visually. However, they also offer novel challenges as they were primarily developed for use as a visual interface. This paper studies key usability parameters governing accurate rendering of haptically-perceivable graphical materials. Three psychophysically-motivated usability studies, incorporating 46 BVI participants, were conducted that identified three key parameters for accurate rendering of vibrotactile lines. Results suggested that the best performance and greatest perceptual salience is obtained with vibrotactile feedback based on: (1) a minimum width of 1 mm for detecting lines, (2) a minimum gap of 4 mm for discriminating lines rendered parallel to each other, and (3) a minimum angular separation (i.e., cord length) of 4 mm for discriminating oriented lines. Findings provide foundational guidelines for converting/rendering visual graphical materials on touchscreen-based interfaces for supporting haptic/vibrotactile information access.

Data visualization has become an increasingly important means of effective data communication and has played a vital role in broadcasting the progression of COVID-19. Accessible data representations, however, have lagged behind, leaving areas of information out of reach for many blind and visually impaired (BVI) users. In this work, we sought to understand (1) the accessibility of current implementations of visualizations on the web; (2) BVI users’ preferences and current experiences when accessing data-driven media; (3) how accessible data representations on the web address these users’ access needs and help them navigate, interpret, and gain insights from the data; and (4) the practical challenges that limit BVI users’ access and use of data representations. To answer these questions, we conducted a mixed-methods study consisting of an accessibility audit of 87 data visualizations on the web to identify accessibility issues, an online survey of 127 screen reader users to understand lived experiences and preferences, and a remote contextual inquiry with 12 of the survey respondents to observe how they navigate, interpret, and gain insights from accessible data representations. Our observations during this critical period of time provide an understanding of the widespread accessibility issues encountered across online data visualizations, the impact that data accessibility inequities have on the BVI community, the ways screen reader users sought access to data-driven information and made use of online visualizations to form insights, and the pressing need to make larger strides towards improving data literacy, building confidence, and enriching methods of access. Based on our findings, we provide recommendations for researchers and practitioners to broaden data accessibility on the web.

It is widely recognized that digital libraries (DLs) should be accessible for all types of users. However, there is a gap in assessing how well DLs support blind and visually impaired (BVI) users. This study evaluated the accessibility of DLs based on the DL Accessibility and Usability Guidelines (DLAUG). A total of 31 DL experts–comprising experienced DL developers–were recruited to assess five DLs representing diverse types. Multiple data collection methods, particularly expert assessments, were employed to gather data. The findings identified 22 types of violations corresponding to various help-seeking situations encountered by BVI users. These violations were classified into the following seven categories: feature labeling issues, inadequate help information, inappropriate design of features, incompatibility, lack of features, metadata issues, and multimedia issues. The significance of the study lies in its evaluation of the current compliance status of DLs, its identification of unique violations compared with other information retrieval (IR) systems, and its recommendations for improving the current DL designs to better support BVI users.

Following a brief review of the light-driven reactions in photosynthetic membranes, two questions are addressed. (1) Why is the first charge separation reaction in photosynthetic reaction centers so fast; and (2) given what we know about the contemporary structure and function of reaction centers, can we develop a simple model for a much more primitive reaction center? It is proposed that the primary charge separation step in reaction centers is optimized to be ultra-fast principally in order to compete with detrapping into the antenna complex, rather than to compete with radiative and non-radiative losses in the special pair. This leads to a notion of kinetic perfection analogous to that developed for enzymes which operate under diffusion-limited conditions, but elaborated to permit even more 'perfect' function. This hypothesis is testable by changing components in photosynthetic membranes and subjecting them to selective pressures. We speculate that the reaction center is far too complex to have served as an early functional unit, and consider possible roles for the iron-quinone part of the reaction center as a very primitive photosynthetic unit. It is suggested that this working end later became associated with primitive antenna complexes, which then evolved into the elaborate structure we find today.The role of photosynthesis in the origin of life has been a topic of speculation for many years. It is evident that photosynthetic function is ancient and central. As a person who does not work in the field of evolution. I am not very familiar with much of the speculation that precedes this paper. Proposals and speculation by others are likely based on much firmer ground, and therefore I apologize in advance if some of these ideas have already been suggested by others. In this chapter I take the liberty to speculate on how a structure as complex as the contemporary photosynthetic reaction center (RC) could have evolved from more primitive units, and why it retains some of its remarkable properties and seemingly unnecessary components. Both subjects lead to specific predictions and testable hypotheses.

A strain of Rhodobacter sphaeroides has been constructed in which the photosynthetic reaction center is the sole pigment-protein complex. The strain, named RCO1, is capable of photoheterotrophic growth and possesses assembled and functional reaction centers which can undergo photochemical charge separation and are reduced by electrons derived from the cytochrome b/c1 complex. The circular dichroism and linear dichroism of reaction centers in membranes from strain RCO1 are similar to those described previously for reaction centers isolated in detergent solution. A second strain, named RCLH11, which is devoid of the peripheral LH2 antenna complex has also been constructed. A description of the properties of these strains is presented.

SummaryGreen sulfur bacterial reaction centers have been usually cited as counterparts of Photosystem I. However, they have remained poorly characterized for a long time, since the main interest was directed towards understanding the unique antenna system of green bacteria, the so-called chlorosomes. Many exciting developments in green sulfur bacterial reaction center research have occurred during the years 1990 to 1995. Important similarities between the reaction centers of green sulfur bacteria, heliobacteria, and Photosystem I have been discovered, such as the presence of the same set of electron acceptors and a similar polypeptide composition. Furthermore, similarities to the purple bacterial-type reaction centers have been described. These include the presence of a bacteriochlorophyll dimer as the primary donor and a reaction-center-associated cytochrome subunit as electron donor to P840. Most surprising, however, has been the discovery of only one gene coding for the dimeric, large reaction center subunits. This feature is in contrast, not only to Photosystem I, but also, to purple bacterial-type reaction centers, and it has raised interesting evolutionary questions which are discussed in this chapter. It has been shown that both types of reaction centers, i.e. purple bacterial- and Photosystem I -type reaction centers share common features, such as the charge separation processes, those pigments involved and a similar organization of the main polypeptides. All this led to the speculation that the different kinds of photosynthetic reaction centers have a common evolutionary origin. In this review we summarize the current state of knowledge about the green sulfur bacterial reaction center structure and function and compare these with those of other Photosystem I-type and purple bacterial reaction centers.

A structure-based modeling and analysis of the primary photophysical reactions in photosystem II (PS-II) core complexes is presented. The modeling is based on a description of stationary and time-resolved optical spectra of the CP43, CP47, and D1-D2-cytb559 subunits and whole core complexes. It shows that the decay of excited states in PS-II core complexes with functional (open) reaction centers (RCs) is limited by the excitation energy transfer from the CP43 and CP47 core antennae to the RC occurring with a time constant of 40-50 ps at room temperature. The chlorophylls responsible for the low energy absorbance bands in the CP43 and CP47 subunits are assigned, and their signatures in hole burning, fluorescence line narrowing, and triplet-minus-singlet spectra are explained. The different locations of these trap states in the CP43 and CP47 antennae with respect to the reaction center lead to a dramatic change of the transfer dynamics at low temperatures. The calculations predict that, compared to room temperature, the fluorescence decay at 77 K should reveal a faster transfer from CP43 and a much slower and highly dispersive transfer from CP47 to the RC. A factor of 3 increase in the fastest decay time constant of fluorescence that was reported to occur when the RC is closed (the plastoquinone QA is reduced) is understood in the present model by assuming that the intrinsic rate constant for primary electron transfer decreases from 100 fs-1 for open RCs to 6 ps-1 for closed RCs, leading to a reduction of the primary electron acceptor PheoD1, in 300 fs and 18 ps, respectively. The model suggests that the reduced QA switches the photosystem into a photoprotective mode in which a large part of the excitation energy of the RC returns to the CP43 and CP47 core antennae, where the physiologically dangerous triplet energy of the chlorophylls can be quenched by the carotenoids. Experiments are suggested to test this hypothesis. The ultrafast primary electron transfer inferred for open RCs provides further support for the accessory chlorophyll ChlD1 to be the primary electron donor in photosystem II.

Through out the design process, designers have to consider the needs of potential users. This is particularly important, but rather harder, when the designers interact with the artefact to-be-designed using different senses or devices than the users, for example, when sighted designers are designing an artefact for use by blind users. In such cases, designers have to ensure that the methods used to engage users in the design process and to communicate design ideas are accessible. In this paper, we describe a participatory approach with blind users based on the use of a scenario and the use of dialogue-simulated interaction during the development of a search interface. We achieved user engagement in two ways: firstly, we involved a blind user with knowledge of assistive technologies in the design team and secondly, we used a scenario as the basis of a dialogue between the designers and blind users to simulate interaction with the proposed search interface. Through this approach, we were able to verify requirements for the proposed search interface and blind searchers were able to provide formative feedback, to critique design plans and to propose new design ideas based on their experience and expertise with assistive technologies. In this paper, we describe the proposed scenario-based approach and examine the types of feedback gathered from its evaluation with blind users. We also critically reflect on the benefits and limitations of the approach, and discuss practical considerations in its application.Keywordsscenarioparticipatory designvisually impaired users

Simple SummaryOne of the great challenges in science is determining when, where, why, and how life first arose as well as the form taken by this life. In the present study, life was assumed to be (1) bounded, (2) replicating, (3) able to inherit information, and (4) able to metabolize energy. The various existing hypotheses provide little explanation of how these four conditions for life were established. Indeed, “how” a chemical process that simultaneously satisfies all four conditions emerged after the materials for life were in place is not always clear. In this study, a multiset chemical lattice model, which allows for virtual molecules of multiple types to be placed in each cell on a two-dimensional space, was considered. Using only the processes of molecular diffusion, reaction, and polymerization and modeling the chemical reactions of 15 types of molecules and 2 types of polymerized molecules, as well as using the morphogenesis rule of the Turing model, the process of emergence of a cell-like form with all three conditions except evolution ability was modeled and demonstrated.Although numerous reports using methods such as molecular dynamics, cellular automata, and artificial chemistry have clarified the process connecting non-life and life on protocell simulations, none of the models could simultaneously explain the emergence of cell shape, continuous self-replication, and replication control solely from molecular reactions and diffusion. Herein, we developed a model to generate all three conditions, except evolution ability, from hypothetical chains of chemical and molecular polymerization reactions. The present model considers a 2D lattice cell space, where virtual molecules are placed in each cell, and molecular reactions in each cell are based on a multiset rewriting rule, indicating stochastic transition of molecular species. The reaction paths of virtual molecules were implemented by replacing the rules of cellular automata that generate Turing patterns with molecular reactions. The emergence of a cell-like form with all three conditions except evolution ability was modeled and demonstrated using only molecular diffusion, reaction, and polymerization for modeling the chemical reactions of 15 types of molecules and 2 types of polymerized molecules. Furthermore, controlling self-replication is possible by changing the initial arrangement of a specific molecule. In summary, the present model is capable of investigating and refining existing hypotheses on the emergence of life.

We present the results of a research project focus on improving the usability of web search tools for blind users who interact via screen reader and voice synthesizer. In the first stage of our study, we proposed eight specific guidelines for simplifying this interaction with search engines. Next, we evaluated these criteria by applying them to Google UIs, re-implementing the simple search and the result page. Finally, we prepared the environment for a remote test with 12 totally blind users. The results highlight how Google interfaces could be improved in order to simplify interaction for the blind.

Function of membrane proteins coupled to bacteriochlorophyll synthesis: Studies with wild type and mutant strains of Rhodopseudomonas spheroides

A DAG scheduling scheme on heterogeneous computing systems using double molecular structure-based chemical reaction optimization