A Blockchain Framework for Patient-Centered Health Records and Exchange (HealthChain): Evaluation and Proof-of-Concept Study

Background: Blockchain has the potential to disrupt the current modes of patient data access, accumulation, contribution, exchange, and control. Using interoperability standards, smart contracts, and cryptographic identities, patients can securely exchange data with providers and regulate access. The resulting comprehensive, longitudinal medical records can significantly improve the cost and quality of patient care for individuals and populations alike. Objective: This work presents HealthChain, a novel patient-centered blockchain framework. The intent is to bolster patient engagement, data curation, and regulated dissemination of accumulated information in a secure, interoperable environment. A mixed-block blockchain is proposed to support immutable logging and redactable patient blocks. Patient data are generated and exchanged through Health Level-7 Fast Healthcare Interoperability Resources, allowing seamless transfer with compliant systems. In addition, patients receive cryptographic identities in the form of public and private key pairs. Public keys are stored in the blockchain and are suitable for securing and verifying transactions. Furthermore, the envisaged system uses proxy re-encryption (PRE) to share information through revocable, smart contracts, ensuring the preservation of privacy and confidentiality. Finally, several PRE improvements are offered to enhance performance and security. Methods: The framework was formulated to address key barriers to blockchain adoption in health care, namely, information security, interoperability, data integrity, identity validation, and scalability. It supports 16 configurations through the manipulation of 4 modes. An open-source, proof-of-concept tool was developed to evaluate the performance of the novel patient block components and system configurations. To demonstrate the utility of the proposed framework and evaluate resource consumption, extensive testing was performed on each of the 16 configurations over a variety of scenarios involving a variable number of existing and imported records. Results: The results indicate several clear high-performing, low-bandwidth configurations, although they are not the strongest cryptographically. Of the strongest models, one’s anticipated cumulative record size is shown to influence the selection. Although the most efficient algorithm is ultimately user specific, Advanced Encryption Standard–encrypted data with static keys, incremental server storage, and no additional server-side encryption are the fastest and least bandwidth intensive, whereas proxy re-encrypted data with dynamic keys, incremental server storage, and additional server-side encryption are the best performing of the strongest configurations. Conclusions: Blockchain is a potent and viable technology for patient-centered access to and exchange of health information. By integrating a structured, interoperable design with patient-accumulated and generated data shared through smart contracts into a universally accessible blockchain, HealthChain presents patients and providers with access to consistent and comprehensive medical records. Challenges addressed include data security, interoperability, block storage, and patient-administered data access, with several configurations emerging for further consideration regarding speed and security

Evaluation and Enhancement of Web Content Accessibility for Persons with Disabilities

Web content accessibility is to which degree a site is accessible to the largest possible range of people, especially for persons with disabilities. The current study comprises four interrelated parts revolving around evaluating and enhancing Web content accessibility.First, a novel measurement metrics called Web Accessibility Barriers (WAB) score is constructed based on published Web accessibility design guidelines. The performance of the measurement metrics is assessed using a Web accessibility gold standard. The Receiver Operating Characteristic (ROC) curve shows that WAB score separate inaccessible Web pages well from accessible ones with Area Under the Curve (AUC) value of 0.917.Second, using the WAB score, I evaluate the degree of Web accessibility of consumer health information websites. Mean of WAB score of the 108 selected websites is 9.31 with standard deviation of 6.29. Among those websites, government and education websites have lower WAB score - 0.39 and 1.16 respectively. ANalysis Of VAriance (ANOVA) test shows statistical significances across different functional categories of the websites (F=9.705, p < 0.001). In addition, this study shows that WAB score correlated with traffic rank of the websites with (r = 0.32, p < 0.01).Third, a usability study is conducted to examine the performance of a Web Transcoder Gateway (WTG) server for blind Web users to access online information. The WTG server removes Web accessibility barriers in real time based on Web accessibility design guidelines. The study design is a within-subject cross-over design. A mixed model analysis is employed to examine the effect of the WTG server on time, success, errors, and subjective measurement. Sixteen blind Web users took part in the study. Results show that participants spent less time, make few errors, and succeed more on the tasks via WTG server. Participants also feel more satisfactory, less frustrated, and more confident when access online information via WTG server. Observational and anecdotal findings imply that only removing accessibility barriers may not be sufficient to achieve the best usability for blind Web users.Finally, a usability study is conducted to examine the performance of a Web Transcoder Gateway (WTG) server for PDA users to access Web sites. The study design is also a within-subject cross-over design. A mixed model analysis is employed to examine the effect of WTG server on time, success, and subjective measurements. Twenty subjects took part in the study. Results show that participants spend less time on each task via WTG server. Each participant can finish the tasks successfully via either WTG server or non WTG server. This implies that the WTG server can serve as "Electronic Curb Cut" for Web users under constraints. However, the participants show no statistically significant preference to WTG server

The Mechanism of Theory-based HIV Behavioral Intervention on Condom Use among Rural-to-urban Migrants in China: The Mediating Roles of HIV Knowledge and Condom Use Self-efficacy

Previous studies have suggested HIV knowledge and self-efficacy are important cognitive factors that might influence condom use behaviors. However, data were limited regarding their mediating effects on condom use during behavioral interventions. This study examined the mechanistic roles of these two factors on the effect of a community-based intervention aiming to increase condom use behaviors and intention among young rural-to-urban migrants in China. Data were derived from a community-based HIV behavioral intervention trial among 639 young sexually active rural-to-urban migrants in Beijing, China. Path analyses were used to examine the direct and indirect effects of the intervention program on condom use behaviors and intention over a 12-month follow-up. HIV knowledge and condom use self-efficacy at 6-month follow-up served as mediators in models. Path analyses revealed that intervention program increased condom use behaviors at 12 months through the increase of HIV knowledge at 6 months. Likewise, the intervention program increased condom use intention through the increases of HIV knowledge and condom use self-efficacy. The results suggested HIV knowledge played an important mediating role on the effect of the intervention program on condom use behaviors and intention. Additionally, condom use self-efficacy played an important role in increasing condom use intention. To increase condom use behaviors and intention among migrants, future studies are warranted that focus on improving HIV knowledge and helping migrants overcome cognitive barriers of condom use. Other efforts targeting structural and environmental barriers, such as limited healthcare access due to household registration status, are also needed to increase HIV protective behaviors

Laboratory study of acoustic velocity in different types of rocks at seismic frequency band

In order to understand the characteristics of acoustic wave propagation in rocks within seismic frequency band (<100 Hz), the velocities of longitudinal and transverse waves of four different types of rocks were tested using low-frequency stress-strain method by means of the physical testing system of rock at low frequency and the experimental data of acoustic velocities of four different types of rocks at this frequency band were obtained. The experimental results showed that the acoustic velocities of four different types of rocks increased with the increase of temperature and pressure within the temperature and pressure ranges set by the experiment. The acoustic velocity of fine sandstone at 50% water saturation was smaller than that of dry sample. The acoustic velocities of four different types of rocks were different and the velocities of longitudinal waves of gritstone, fine sandstone, argillaceous siltstone and mudstone increased in turn under similar conditions and were smaller than those at ultrasonic frequency. Few of existing studies focus on the acoustic velocity at seismic frequency band, thus, further understanding of the acoustic characteristics at this seismic frequency band still requires more experimental data

Multi-Channel Magnetocardiogardiography System Based on Low-Tc SQUIDs in an Unshielded Environment

AbstractMagnetocardiography (MCG) using superconducting quantum interference devices (SQUIDs) is a new medical diagnostic tool measuring biomagnetic signals that are generated by the electrical activity of the human heart. This technique is completely passive, contactless, and it has an advantage in the early diagnosis of heart diseases. We developed the first unshielded four-channel MCG system based on low-Tc DC SQUIDs in China. Instead of using a costly magnetically shielded room, the environmental noise suppression was realized by using second-order gradiometers and three-axis reference magnetometer. The measured magnetic field resolution of the system is better than 1 pT, and multi-cycle human heart signals can be recorded directly. Also, with the infrared positioning system, 48 points data collection can be realized by moving the non-magnetic bed nine times