Cheer for me: effect of non-player character audience feedback on older adult users of virtual reality exergames.

The presence of an audience and its feedback could affect people's performance and experience during an event, especially related to sports such as tennis or boxing. Similarly, in videogames, players' gameplay could be affected if there is an audience and its feedback in response to players' performance in the environment. The inclusion of an audience with non-player characters (NPC) is common in videogames in general. However, there is a limited exploration of the use of an NPC audience in virtual reality (VR) exergames, especially focusing on elderly players. To fill this gap, this work examines the effect of an NPC audience and its associated feedback (with/without) on elderly users of VR exergames. In a user study, we used 120 NPC in a virtual audience. Results showed that the presence of the NPC audience with responsive feedback led to higher performance (with a higher success rate of performing gesture actions, more successful combinations of actions (or combos for short) performed, and more opponent's combos prevented) and better gameplay experience (with higher levels of competence, autonomy, relatedness, immersion, and intuitive controls) of elderly players. Our results can help frame the design and engineering of VR exergames that are targeted at elderly users to help them have an enhanced gameplay experience and improve their health.

Understanding the Relationship Between User Game Preferences and Depressive Symptoms: A Pilot Study.

Objective: Following the initial measures taken to manage the repercussions of the COVID-19 pandemic, mental health conditions have become a critical concern. Mental health has become a foremost priority not only for health care providers but also for many other organizations, such as educational institutions, companies, and government agencies. A significant proportion of the Australian population having experienced mental disorders highlights the need for effective interventions. Those with pre-existing mental health issues experienced particularly pronounced effects. Among these challenges, advancements in technology offer new possibilities for mental health support. Videogames have shown effectiveness in mitigating symptoms of depression. Previous research has shown that game interface preferences correlate with players' emotional responses. This study aims to use MoodJumper, a game we designed, developed, and evaluated to examine the choice of game preferences in individuals with depressive symptoms. Materials and Methods: A pilot study was carried out after obtaining the Human Ethics committee's approval (n = 20). The participants were asked to fill out a Patient Health Questionnaire-9 (PHQ-9) questionnaire. They then played with the MoodJumper game for 20-30 minutes. Upon completing the game session, they were asked to fill out a questionnaire regarding their experience. Results: The results indicate a nonsignificant correlation between music preference, the direction of movement, and depressive symptoms meaning no significant relationship was found between depressive symptoms and chosen settings. However, a significant negative correlation was found between decision-making ability regarding game preferences and Patient Health Questionnaire-9 scores showing the difficulty of choosing preferred settings when having depressive symptoms. Conclusion: This contribution paves the way for designing and evaluating more impactful game experiences for individuals with mental health challenges.

Breaking the Isolation: Exploring the Impact of Passthrough in Shared Spaces on Player Performance and Experience in VR Exergames.

VR exergames offer an engaging solution to combat sedentary behavior and promote physical activity. However, challenges emerge when playing these games in shared spaces, particularly due to the presence of bystanders. VR's passthrough functionality enables players to maintain awareness of their surrounding environment while immersed in VR gaming, rendering it a promising solution to improve users' awareness of the environment. This study investigates the passthrough's impact on player performance and experiences in shared spaces, involving an experiment with 24 participants that examines Space (Office vs. Corridor) and Passthrough Function (With vs. Without). Results reveal that Passthrough enhances game performance and environmental awareness while reducing immersion. Players prefer an open area to an enclosed room, whether with or without Passthrough, finding it more socially acceptable. Additionally, Passthrough appears to encourage participation among players with higher self-consciousness, potentially alleviating their concerns about being observed by bystanders. Our findings provide valuable insights for designing VR experiences in shared spaces, underscoring the potential of VR's passthrough to enhance user experiences and promote VR adoption in these environments.

Exploring the effect of the Group Size and Feedback of non-player character spectators in virtual reality exergames.

Despite the widespread interest in leveraging non-player characters (NPCs) to enhance gameplay experiences, there is a gap in understanding of how NPC spectators (i.e., those virtual characters in the scene that watch users' actions) affect players. For instance, the impact of NPC spectators' presence and feedback on players' performance and experience has not been studied, especially in virtual reality (VR) exergames. This paper aims to fill this gap and reports two user studies that assess their effect on such games. Study 1 explored the impact of having NPC spectators present and their feedback available in a gesture-based VR exergame and found having NPC spectators and their feedback could improve players' game performance, experience, and exertion. Based on Study 1's results, we further explored two characteristics of the spectators-their group size (small/large) and their feedback (with/without). The results show that (1) a large spectator number is more helpful since it improves the overall game experience (higher competence, flow, immersion), increases AvgHR% (the average heart rate percentage divided by the maximum heart rate), and enhances performance (improved players' combo performance and increased gesture success rate for particular gesture); (2) spectator feedback is instrumental in improving players' performance (higher gesture success rates, more combos performed successfully, more monster's combos prevented), enhancing game experience (positive affect, competence, flow, and immersion), and reducing negative game experience, increasing exertion (AvgHR% and burned more calories). Based on the results, we derived two main design recommendations for VR exergames that could pave the way for improving gameplay performance and game experience, especially among young adults.

Root growth and architecture of Tamarix chinensis in response to the groundwater level in the Yellow River Delta.

AIMS: Investigate the growth adaptation law of the Tamarix chinensis root system in response to the groundwater level in a muddy coastal zone. METHODS: The high groundwater level (0.7-0.9 m), medium groundwater level (1.1-1.3 m) and low groundwater level (1.5-1.7 m) T. chinensis forests on the beaches of the Yellow River Delta were used as the research objects. Full excavation methods were used to excavate root systems with different groundwater levels; then, the aboveground biomass, root biomass, root spatial distribution, root topological structure and fractal characteristics of T. chinensis response characteristics to groundwater level were measured and analysed. RESULTS: The results showed that with the decrease in the groundwater level, the soil water content and soil salt content showed upward trends. At high groundwater levels, T. chinensis reduced root biomass allocation to reduce the damage to roots caused by salinity. At low groundwater levels, T. chinensis strengthened the development of root systems, which greatly enhanced the ability of T. chinensis to balance its water intake. The root biomass at the high groundwater level was 43.06% lower than that at the low groundwater level. The relationship between root and shoot growth of T. chinensis at high groundwater levels and medium groundwater levels indicated allometric growth, and at low groundwater levels, roots and shoots grew uniformly. The root distribution of T. chinensis tended to be shallow at the different groundwater levels, showing the characteristics of a horizontal root type. At high groundwater levels, the root topological structure tended to be dichotomous, and the fractal dimension and fractal abundance values were both large, at 1.31 and 2.77, respectively. The branch complexity increased to achieve spatial expansion and increase plant stability. However, the topological structure of the medium and low groundwater level T. chinensis tended to be herringbone-like, the fractal dimension and fractal abundance values were small, the second branch was limited, and the structure was simple. The topological structure and fractal characteristics of the T. chinensis root system responded to different groundwater levels in a coordinated manner. CONCLUSIONS: Based on the differences in the growth and architecture of the T. chinensis root system, the T. chinensis root system has strong phenotypic plasticity to the heterogeneous water-salt habitat of the groundwater-soil system, and the T. chinensis root system shows strong root adaptability to water and salt stress.

Effects of an Immersive Virtual Reality Exergame on University Students' Anxiety, Depression, and Perceived Stress: Pilot Feasibility and Usability Study.

BACKGROUND: In recent years, there has been an increase in the number of students with depression, anxiety, and perceived stress. A solution that has been increasingly used for improving health and well-being is exergaming. The effects and acceptability of exergames have been studied widely but mostly with older adults. The feasibility and usability of exergames among university students, especially those of immersive virtual reality (iVR) exergames, remain unexplored. OBJECTIVE: This study aimed to explore the feasibility of a 6-week iVR exergame-based intervention in reducing anxiety, depression, and perceived stress among university students and to examine the usability and acceptability of such games. METHODS: A total of 31 university students were recruited to participate in a 6-week study in which they needed to play a boxing-style iVR exergame called FitXR (FitXR Limited) twice per week (30 minutes per session). Their anxiety (Beck Anxiety Inventory), depression (Beck Depression Inventory-II), and perceived stress (Perceived Stress Scale) levels were measured before and after intervention. RESULTS: A total of 15 participants completed the 6-week study. Our results suggested that participants' mean depression scores decreased significantly from 8.33 (SD 5.98) to 5.40 (SD 5.14) after the intervention (P=.01). In addition, most participants (14/15, 93%) believed that the iVR exergame has good usability. Furthermore, most participants (14/15, 93%) were satisfied with the iVR gameplay experience and would play the iVR exergame again in the future. Of the 15 participants, 11 (73%) would recommend the iVR exergame to their friends. CONCLUSIONS: The results gained from this study show that the iVR exergame has good usability, is highly acceptable, and has the potential to reduce depression levels among university students.

Synthesis of a Cyclophosphazene Derivative Containing Multiple Cyano Groups for Electron-Beam Irradiated Flame-Retardant Materials.

A cyclophosphazene derivative containing multiple cyano groups, denoted as hexa(4-cyanophenoxy)cyclotriphosphazene (CN-CP), was synthesized by a one-step nucleophilic substitution reaction for a phosphorus-nitrogen flame retardant. To meet the strict requirement of safe and environment-protective insulation materials, a series of composites based on low-density polyethylene-poly(ethylene-co-vinyl acetate) containing CN-CP/Mg(OH)2/Al(OH)3 organic-inorganic synergistic flame retardants was fabricated. High-energy electron beam irradiation was subsequently applied to obtain a halogen-free flame-retardant crosslinked system. The relationship between crosslinking degree and irradiation dose was studied, and crosslinking degrees ranging within 63-85% were obtained under 100-190 kGy. Furthermore, the effects of CN-CP filler and irradiation dose on the properties of the composites were carefully investigated. The maximum tensile stress and limiting oxygen index values of most composites irradiated by EB were more than 15 MPa and 28%. Results revealed that the obtained materials had excellent thermal and mechanical, flame-retardant, and insulation properties, thereby suggesting their promising prospects for wire and cable applications.

Studying the Effect of Display Type and Viewing Perspective on User Experience in Virtual Reality Exergames.

Background: Physical inactivity has been identified as the fourth leading cause of death globally. It is now well established that a sedentary lifestyle is a unique risk factor for several diseases such as type 2 diabetes and cardiovascular disease, which account for about 30% of global mortality. Diabetes is a major preventable cause of costly and debilitating renal failure, heart disease, lower limb amputation, and avoidable blindness. In recent years, the idea of using interactive computing systems that leverage gamification to promote physical activity has been widely researched. Prior studies have shown that exergames, that is those that encourage physical activity, can increase enjoyment and intrinsic motivation compared with conventional exercises; as such, they can be effective in promoting physical and mental health. There has been some research on immersive virtual reality (VR) exergames; however, to the best of our knowledge, it is limited and preliminary. This work aims at filling the gap and investigates the effect of display type (DT) and viewing perspective (VP) on players' exertion, engagement, and overall game experience in immersive VR exergames. Objective: This article aims at examining whether DT and VP can affect gameplay performance, players' exertion, game experience, cybersickness, and electroencephalography (EEG) engagement index when playing a gesture-based (i.e., body motion) exergame. Materials and Methods: Study 1 employed a one-way between-subjects design with 24 participants equally distributed in two groups (immersive VR and 50-inch TV) to perform 12 pre-defined gestures. The main outcome measures were National Aeronautics and Space Administration-Task Load Index (NASA-TLX) workload for each group as well as 7 Likert scale and EEG engagement index for each gesture. Study 2 included 16 participants in playing a game with the gestures selected from study 1. All participants played 4 versions based on combinations of DT (immersive VR and 50-inch TV) and VP (first-person and third-person) to assess exertion (%HRmax, calories consumption, and Borg RPE 6-20), game experience, cybersickness, and EEG engagement index. Results: Study 1 results showed that DT had no effect on the ratings of the gestures, NASA-TLX workload, and EEG engagement index. Study 2 results showed that immersive VR not only resulted in a significantly higher exertion (%HRmax, calories consumption, and Borg RPE) but also helped achieve better positive game experience in challenge, flow, sensory and imaginative immersion, as well as lower negative affect. We also found that nausea and oculomotor were significantly higher in immersive VR. Conclusion: This pilot study demonstrates that youth who played gesture-based exergame in immersive VR had a higher level of exertion (%HRmax, calories consumption, and Borg RPE), although the number of performed gestures were not significantly different. They also felt that immersive VR was much more challenging, immersive (flow, sensory and imaginative immersion), and had a lower negative affect than a 50-inch TV; however, immersive VR was more likely to make youth have higher cybersickness.

Results and Guidelines From a Repeated-Measures Design Experiment Comparing Standing and Seated Full-Body Gesture-Based Immersive Virtual Reality Exergames: Within-Subjects Evaluation.

BACKGROUND: Although full-body seated exercises have been studied in a wide range of settings (ie, homes, hospitals, and daycare centers), they have rarely been converted to seated exergames. In addition, there is an increasing number of studies on immersive virtual reality (iVR) full-body gesture-based standing exergames, but the suitability and usefulness of seated exergames remain largely unexplored. OBJECTIVE: This study aimed to evaluate the difference between playing a full-body gesture-based iVR standing exergame and seated exergame in terms of gameplay performance, intrinsic motivation, and motion sickness. METHODS: A total of 52 participants completed the experiment. The order of the game mode (standing and sitting) was counterbalanced. Gameplay performance was evaluated by action or gesture completion time and the number of missed gestures. Exertion was measured by the average heart rate (HR) percentage (AvgHR%), increased HR%, calories burned, and the Borg 6-20 questionnaire. Intrinsic motivation was assessed with the Intrinsic Motivation Inventory (IMI), whereas motion sickness was assessed via the Motion Sickness Assessment Questionnaire (MSAQ). In addition, we measured the fear of falling using a 10-point Likert scale questionnaire. RESULTS: Players missed more gestures in the seated exergame than in the standing exergame, but the overall miss rate was low (2.3/120, 1.9%). The analysis yielded significantly higher AvgHR%, increased HR%, calories burned, and Borg 6-20 rating of perceived exertion values for the seated exergame (all P<.001). The seated exergame was rated significantly higher on peripheral sickness (P=.02) and sopite-related sickness (MSAQ) (P=.004) than the standing exergame. The score of the subscale "value/usefulness" from IMI was reported to be higher for the seated exergame than the standing exergame. There was no significant difference between the seated exergame and standing exergame in terms of intrinsic motivation (interest/enjoyment, P=.96; perceived competence, P=.26; pressure/tension, P=.42) and the fear of falling (P=.25). CONCLUSIONS: Seated iVR full-body gesture-based exergames can be valuable complements to standing exergames. Seated exergames have the potential to lead to higher exertion, provide higher value to players, and be more applicable in small spaces compared with standing exergames. However, gestures for seated exergames need to be designed carefully to minimize motion sickness, and more time should be given to users to perform gestures in seated exergames compared with standing exergames.

Health Benefits of Digital Videogames for the Aging Population: A Systematic Review.

Objective: This article presents the results of a systematic review of the latest, state-of-the-art research on videogames designed for older adults (i.e., those aged 65 or older) and the health benefits derived from playing these games. Findings from each study that met the inclusion criteria were analyzed and summarized into emergent themes to determine the impact of digital games in promoting healthy behaviors and benefits among these older adults. Materials and Methods: Five databases (PubMed, ScienceDirect, IEEE Xplore, ACM Digital Library, and Google Scholar) were searched for studies that evaluated interventions of videogames for older adults aged 65 and older. The initial search yielded 806 articles. After evaluating them against the inclusion criteria, 23 studies remained. Results: Out of the 23 studies we reviewed, 20 reported the significant impact of videogame interventions on the elderly's physical health. In addition, 14 studies reported effects on the elderly's mental health. Exergame is the most popular type of game used in these videogame-based interventions. This review also includes the details of study design (e.g., type of intervention, length, frequency), population sample, and measurements used in the studies. Conclusions: This systematic review demonstrates that videogame-based interventions are helpful in promoting physical health (i.e., balance, mobility, strength, physical fitness, and walking performance/gait parameters) and mental health (i.e., balance confidence, executive functions, reaction time, and processing speed) among older adults. It can also be used by researchers in this field to inform their design decisions. We have listed guidelines that can be used to frame future research in the area and enhance its quality.

RingText: Dwell-free and hands-free Text Entry for Mobile Head-Mounted Displays using Head Motions.

In this paper, we present a case for text entry using a circular keyboard layout for mobile head-mounted displays (HMDs) that is dwell-free and does not require users to hold a dedicated input device for letter selection. To support the case, we have implemented RingText whose design is based on a circular layout with two concentric circles. The outer circle is subdivided into regions containing letters. Selection is made by using a virtual cursor controlled by the user's head movements-entering a letter region triggers a selection and moving back into the inner circle resets the selection. The design of RingText follows an iterative process, where we initially conduct one first study to investigate the optimal number of letters per region, inner circle size, and alphabet starting location. We then optimize its design by selecting the most suitable features from the first study: one letter per region, narrowing the trigger area to lower error rates, and creating candidate regions that incorporate two suggested words to appear next to the current letter region (close to the cursor) using a dynamic (rather than fixed) approach. Our second study compares text entry performance of RingText with four other hands-free techniques and the results show that RingText outperforms them. Finally, we run a third study lasting four consecutive days with 10 participants (5 novice users and 5 expert users) doing two daily sessions and the results show that RingText is quite efficient and yields a low error rate. At the end of the eighth session, the novice users can achieve a text entry speed of 11.30 WPM after 60 minutes of training while the expert (more experienced) users can reach an average text entry speed of 13.24 WPM after 90 minutes of training.

PizzaText: Text Entry for Virtual Reality Systems Using Dual Thumbsticks.

We present PizzaText, a circular keyboard layout technique for text entry in virtual reality (VR) environments that uses the dual thumbsticks of a hand-held game controller. Text entry is a common activity in VR environments but remains challenging with existing techniques and keyboard layouts that is largely based on QWERTY. Our technique makes text entry simple, easy, and efficient, even for novice users. The technique uses a hand-held controller because it is still an important input device for users to interact with VR environments. To allow rapid search of characters, PizzaText divides a circle into slices and each slice contains 4 characters. To enable fast selection, the user uses the right thumbstick for traversing the slices, and the left thumbstick for choosing the letters. The design of PizzaText is based on three criteria: efficiency, learnability, and ease-of-use. In our first study, six potential layouts are considered and evaluated. The results lead to a design with 7 slices and 4 letters per slice. The final design is evaluated in a five-day study with 10 participants. The results show that novice users can achieve an average of 8.59 Words per Minute (WPM), while expert users are able to reach 15.85 WPM, with just two hours of training.

Association of high normal HbA1c and TSH levels with the risk of CHD: a 10-year cohort study and SVM analysis.

This study aimed to determine the association between the clinical reference range of serum glycated hemoglobin A1c (HbA1c) and thyrotropin (TSH) and the risk of coronary heart disease (CHD) in non-diabetic and euthyroid patients. We examined baseline HbA1c and TSH in 538 healthy participants, and then analyzed the associations and potential value of these indicators for predicting CHD using Cox proportional hazard and support vector machine analyses. During the median follow-up of 120 months, 39 participants later developed CHD. The baseline HbA1c and TSH within the reference range were positively associated with CHD risk. No correlation and interaction were found between the baseline HbA1c and TSH for the development of CHD. Disease event-free survival varied among participants with different baseline HbA1c quintiles, whereas disease event-free survival was similar for different TSH tertiles. The combination of these baselines showed sensitivity of 87.2%, specificity of 92.7%, and accuracy of 92.3% for identifying the participants who will later develop CHD. Relatively high but clinically normal HbA1c and TSH levels may increase the risk of CHD. Therefore, the combination of these indicators can serve as a biomarker for identifying healthy individuals from those who would later develop CHD.

A direct competitive enzyme linked immunosorbent assay for progesterone using monoclonal antibody.

A direct competitive enzyme-linked immunosorbent assay (ELISA) with monoclonal antibody (MAb) was diagnosed with progesterone (P) level of human serum. In high concentrations and large amounts of displacer effect, this monoclonal antibody (MAb) can retain biological activity so that it can be specially combined with progesterone. Under conditions of the existing displaced agent, monoclonal antibody 11F8(3)H5 can maintain high specificity and affinity and can specifically bind progesterone in serum. Progesterone ELISA standard curve was calculated according to the following formula: Logit(y) = -1.358Log(x) + 0.4961, r = 0.9944. The serum progesterone values obtained by this method correlated well with those obtained by chemiluminescent immunoassay (CLIA): the correlative equation was y = 0.7804x + 0.7600, r = 0.9126.

Chemiluminescence immunoassay for chloramphenicol.

In recent years, various chemiluminescent clinical immunoassay kits have been widely applied to the detection of hormones. However, a kit for chloramphenicol (CAP) is often absent from most commercial product lists, even though it is important to control the levels of CAP residues in foodstuffs too. Therefore, we describe a simple, solid-phase chemiluminescence immunoassay (CLIA) for the measurement of CAP in foodstuffs. A rabbit anti-CAP IgG is passively adsorbed onto the walls of polypropylene plates. The labeled antigen is horseradish peroxidase (HRP) conjugate of CAP. Luminol solution is used as the substrate of HRP. The light yield is inversely proportional to the concentration of CAP. The method has a similar sensitivity (0.05 ng/ml), specificity, precision, and accuracy to a conventional enzyme immunoassay (EIA). The intra-assay and inter-assay CVs of ten samples were <8% and <20%, respectively, and the analytical recovery of the method was 87-100%. The experimental correlation coefficient of dilution was found to be 0.999 using milk supernatant as buffer. The detection limit for the method was 0.1-10 ng/ml, and it displayed good linearity.