Trade-Off between Task Accuracy, Task Completion Time and Naturalness for Direct Object Manipulation in Virtual Reality

Virtual reality devices are used for several application domains, such as medicine, entertainment, marketing and training. A handheld controller is the common interaction method for direct object manipulation in virtual reality environments. Using hands would be a straightforward way to directly manipulate objects in the virtual environment if hand-tracking technology were reliable enough. In recent comparison studies, hand-based systems compared unfavorably against the handheld controllers in task completion times and accuracy. In our controlled study, we com-pare these two interaction techniques with a new hybrid interaction technique which combines the controller tracking with hand gestures for a rigid object manipulation task. The results demonstrate that the hybrid interaction technique is the most preferred because it is intuitive, easy to use, fast, reliable and it provides haptic feedback resembling the real-world object grab. This suggests that there is a trade-off between naturalness, task accuracy and task completion time when using these direct manipulation interaction techniques, and participants prefer to use interaction techniques that provide a balance between these three factors.publishedVersionPeer reviewe

Comparison of a VR Stylus with a Controller, Hand Tracking, and a Mouse for Object Manipulation and Medical Marking Tasks in Virtual Reality

In medical surgery planning, virtual reality (VR) provides a working environment, where 3D images of the operation area can be utilized. VR allows 3D imaging data to be viewed in a more realistic 3D environment, reducing perceptual problems and increasing spatial understanding. In the present experiment, we compared a mouse, hand tracking, and a combination of a VR stylus and a grab-enabled VR controller as interaction methods in VR. The purpose was to investigate the suitability of the methods in VR for object manipulation and marking tasks in medical surgery planning. The tasks required interaction with 3D objects and high accuracy in the creation of landmarks. The combination of stylus and controller was the most preferred interaction method. According to subjective results, it was considered as the most appropriate because it allows the manipulation of objects in a way that is similar to the use of bare hands. In the objective results, the mouse interaction method was the most accurate.publishedVersionPeer reviewe

2-[2-(4-(trifluoromethyl)phenylamino)thiazol-4-yl]acetic acid (Activator-3) is a potent activator of AMPK

AMPK is considered as a potential high value target for metabolic disorders. Here, we present the molecular modeling, in vitro and in vivo characterization of Activator-3, 2-[2-(4-(trifluoromethyl)phenylamino)thiazol-4-yl]acetic acid, an AMP mimetic and a potent pan-AMPK activator. Activator-3 and AMP likely share common activation mode for AMPK activation. Activator-3 enhanced AMPK phosphorylation by upstream kinase LKB1 and protected AMPK complex against dephosphorylation by PP2C. Molecular modeling analyses followed by in vitro mutant AMPK enzyme assays demonstrate that Activator-3 interacts with R70 and R152 of the CBS1 domain on AMPK γ subunit near AMP binding site. Activator-3 and C2, a recently described AMPK mimetic, bind differently in the γ subunit of AMPK. Activator-3 unlike C2 does not show cooperativity of AMPK activity in the presence of physiological concentration of ATP (2 mM). Activator-3 displays good pharmacokinetic profile in rat blood plasma with minimal brain penetration property. Oral treatment of High Sucrose Diet (HSD) fed diabetic rats with 10 mg/kg dose of Activator-3 once in a day for 30 days significantly enhanced glucose utilization, improved lipid profiles and reduced body weight, demonstrating that Activator-3 is a potent AMPK activator that can alleviate the negative metabolic impact of high sucrose diet in rat model

Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

Designing hand-based interaction for precise and efficient object manipulation in Virtual Reality

Perceiving 3D anatomical data on a 2D screen is complicated, error-prone, and re- quires training for medical professionals because they must mentally reconstruct 3D data from 2D. When they perceive this 3D data in virtual reality, it reduces the 3D to 2D information loss, operating time, and cognitive load. Research in virtual reality applications for jaw osteotomy operation planning has explored interaction techniques using tracker, 3D pen, and haptic pen. However, medical professionals would like to use their hands as they do not need additional hardware and learn how to use it. Using hands as an input in virtual reality can be challenging because of noisy hand tracking caused by occlusion, head egomotion, lack of field of view (FOV), and lack of haptic feedback. In the process of jaw osteotomy operation planning, maximum accuracy is required for adjusting the osteotomy plane because this is the final step, and it compensates for the errors in the previous steps. This work focuses on designing and evaluating precise and efficient hand-based interaction techniques for plane alignment in virtual reality. In the design process, a contextual inquiry is conducted to understand the task. Then, literature review of hand-based object manipulation interaction techniques in virtual reality was conducted to create a tax- onomy of design factors. Then, potential design factors for hand-based interaction techniques were selected, based on which two interaction techniques were designed and further refined using pilot tests. A controlled experiment with 12 participants was conducted, to evaluate these two interaction techniques of (1) push and poke and (2) custom axis with C/D gain, for the plane alignment task using pinch-based direct manipulation as a baseline. From the study, it was found that push and poke was subjectively ranked more precise and preferred because it was faster, easy to learn and use and participants are confident using it. Based on the results of the study, design implications for future hand-based interaction techniques for precise plane alignment in virtual reality are discussed

Object segmentation using independent motion detection

Independent motion detection aims at identifying elements in the scene whose apparent motion is not due to the robot egomotion. In this work, we propose a method that learns the input-output relationship between the robot motion - described by the position and orientation sensors embedded on the robot - and the sparse visual motion detected by the cameras. We detect independent motion by observing discrepancies (anomalies) between the perceived motion and the motion that is expected given the position and orientation sensors on the robot. We then perform a higher level analysis based on the available disparity map, where we obtain dense profile of the objects moving independently from the robot. We implemented the proposed pipeline on the iCub humanoid robot. In this work, we report a thorough experimental analysis that covers typical laboratory settings, where the effectiveness of the method is demonstrated. The analysis shows in particular the robustness of the method to scene and object variations and to different kinds of robot's movements

Informed consent: A study of experiences and opinion of utilizers of health services from India

One hundred and forty-eight subjects drawn from urban and rural settings who had been hospitalized for any medical problem within the previous three years were interviewed using a semi structured interview schedule to understand their opinion and experiences of informed consent. Sixty medical officers providing primary care in both urban and rural areas were concurrently interviewed to gather their opinion. Results revealed that respondents were dissatisfied with the information they had received about the different aspects of their illness. Both the doctors and the patients felt the need for providing adequate information to utilizers of health services. The two groups identified certain constraints, like illiteracy, in obtaining informed consent. Doctors compared to patients more often thought that illiterates could not understand the information. Patients more often felt that information about nature of investigations and about prognosis need not be routinely revealed.informed consent experiences and opinion utilizers of health services India

Anticancer properties of nanoparticle synthesized from Cyphostemma auriculatum Roxb. on nude mice

The present study was aimed to establish the pharmacological and therapeutic properties of a green synthesized silver nanoparticles (AgNPs) in breast cancer induced by 7,12-dimethylbenzanthracene (DMBA) in nude mice. In this study, AgNPs made from Cyphostemma auriculatum Roxb. leaf extract( CA-AgNPs) were tested in a nude mice model for anticancer activity. A significant elevate changes in blood chemistry like heamoglobin, RBC, WBC,&nbsp; platelets and also on blood biochemical parameters such as catalase and SOD with obtained after 28 days of treatment with carcinogen. However, these levels were restored to normal at the end of the study period treated with CA-AgNPs. The liver oxidative stress enzymes showed no significant alterations. With 15 and 30 mg/kg b.w of CA-AgNP, histopathological analysis revealed no significant abnormalities in the kidney, spleen, lungs, heart, testis, or brain. However, 30 mg/kg b.w. of CA-AgNPs caused considerable cell edema and vacuolar degeneration in the liver, which returned to normal at the conclusion of the washout period. The findings of this study suggest that green produced CA-AgNPs at low concentrations could be beneficial