Constitutive testing of soil on the dry side of critical state

Ph.DDOCTOR OF PHILOSOPH

Body area networks at radio frequencies : creeping waves and antenna analysis

On-body communication technology development requires a better knowledge of antenna radiation and wave propagation along the body, in both near and far fields. Therefore, Green's functions associated with penetrable cylinders are briefly reviewed, considering frequencies at which the body is not much larger than the wavelength and with a particular attention given to the near fields. A unified approach based on current sheets is provided and an acceleration technique is proposed. This is validated with the help of an FDTD software, which also allows the analysis of non-canonical cross-sections. The properties of creeping waves launched by sources parallel and perpendicular to the body are studied, in particular from the point of view of their phase velocity, and a very simple fitting model is proposed. It is also explained how the Green function can be exploited to analyze antennas very efficiently with the help of an integral-equation approach

Integrating capacity development during digital health research: a case study from global health

Background: The Bloomberg Data for Health Initiative Research and Development Arm at Johns Hopkins University Bloomberg School of Public Health, has thus far collected NCD risk factor data from more than 13,000 citizens of three LMICs (Bangladesh, Tanzania and Uganda), and has actively worked to improve capacity with partners worldwide. Objective: This paper focuses on how a research project, can also act as a capacity building activity through its research into collecting non-communicable disease risk factor data using different mobile phone modalities. Methods: This paper evaluates the activities undertaken by the project using the ESSENCE Planning Monitoring and Evaluation Framework for Research Capacity Strengthening. Results: The project was able to successfully integrate meaningful capacity development activities across all partners. Training, networking, sharing resources, joint data collection, and analysis across individual, organizational and project levels were some of the strategies used. The ESSENCE framework allowed a good assessment strategy for this type of work. Conclusions: This paper highlights the value of making capacity development a high priority for digital health research activities, while also considering the need to monitor and evaluate those activities in order for them to be meaningful and sustainable. It also considers how to utilize the ESSENCE Framework to evaluate capacity development activities through research, and how best to adapt the Framework to different programs

Spatial Differences in Diet Quality and Economic Vulnerability to Food Insecurity in Bangladesh: Results from the 2016 Household Income and Expenditure Survey

The study explored the spatial differences in diet quality and economic vulnerability to food insecurity with the association of sociodemographic characteristics at the household level in Bangladesh. This study was a secondary data analysis of Household Income and Expenditure Survey (HIES) data of 2016. Both statistical and spatial analyses were applied while assessing diet qualities in terms of the household dietary diversity score (HDDS), percentage of food energy from staples (PFES), and percentage of expenditure on food (PEF) as an indicator of the economic vulnerability to food insecurity (EVFI). The study’s findings revealed that the quality of people’s diets worsened as they moved from urban to rural area, and EVFI increased as they moved from the center to the periphery of the country. Nationally, the average HDDS was about 6.3, and the average PFES per household per day was about 70.4%. The spatial distribution of HDDS and PFES showed that rural regions in terms of settlements and the north, northwest and southeast regions had mostly low diet diversity. Besides, the average PEF per household per day was about 54%, with the highest in Mymensingh (57.4%) and the lowest in Dhaka division (50.2%). The average PEF in the households illustrated was highest in rural (55.2%) and lowest in the city (45.7%). Overall, based on the PEF at the sub-district level, the medium level of vulnerability comprised the highest share (69%) in Bangladesh. Age, gender, literacy, educational qualification and religion of the household’s head along with the number of earners, monthly income, area of settlements and divisions were significantly correlated with HDDS, PFES and EVFI. The study findings suggest that targeted interventions, including access to education, women empowerment and employment generation programs should be implemented in peripheral areas (north, northwest and southeast) to increase diet quality and minimize economic vulnerability to achieve sustainable food and nutrition security in Bangladesh

Switchable THz Guided Mode Enhancement in Subwavelength Thick PTFE — Polyimide Based Metamaterial Devices

We report an efficient approach to enhance terahertz (THz)-guided modes for realizing subwavelength thick metamaterial devices (MMD). Here, a combination of hollow and slitted rings of the vanadium dioxide ( $VO_{2}$ )-based metasurface, having perfect impedance matching with free space, is considered to cause tight coupling in the unit cells while reducing transverse field components of the boundary. The consolidated dielectric layer of polytetrafluoroethylene (PTFE)-polyimide underneath, maintaining a gradual change in refractive indices, brings about further improvement for a broader spectrum. Through strategic and systematic design steps, a maximum impedance bandwidth of 5.68 THz, ranging from 4.42 to 10.10 THz, has been achieved here from a structure thinner than a wavelength. Additionally, mode-independent polarization insensitivity and tunability are attained through the symmetrical unit cell pattern of temperature-dependent $VO_{2}$ . Optimized design parameters agree with interference cancellation theory too. Validation of our presented design is performed using theoretical analysis based on equivalent circuit theory. The proposed design offers a new avenue for designing ultra-thin broadband absorbers, light modulators, etc

Comparison of different suturing techniques in post-extraction socket healing

Background: The process of post-extraction socket healing is critical for ensuring proper tissue repair and minimizing complications in dental practice. Suturing techniques play a pivotal role in this process, influencing wound closure, hemostasis, and overall healing. Materials and Methods: This prospective clinical trial involved 80 participants who required single-tooth extractions. Patients were randomly assigned to four groups, each receiving a distinct suturing technique: simple interrupted sutures, horizontal mattress sutures, vertical mattress sutures, and continuous sutures. Standardized assessments, including clinical examination and cone-beam computed tomography (CBCT) scans, were performed at baseline, 1 week, and 4 weeks post-extraction. Wound dehiscence, soft tissue healing, and bone preservation were evaluated. Results: At 1-week post-extraction, the continuous suture group exhibited the lowest rate of wound dehiscence (5%) compared to other groups (simple interrupted, 15%; horizontal mattress, 10%; vertical mattress, 12%). Soft tissue healing scores at 4 weeks were significantly higher in the continuous suture group (8.7 ± 0.5) than in the other groups (simple interrupted, 7.2 ± 0.8; horizontal mattress, 7.8 ± 0.7; vertical mattress, 7.5 ± 0.6). CBCT analysis revealed superior bone preservation in the continuous suture group (98% remaining bone volume) compared to the other groups (simple interrupted, 92%; horizontal mattress, 95%; vertical mattress, 94%). Conclusion: This study demonstrates that the continuous suturing technique offers advantages in post-extraction socket healing, including reduced wound dehiscence, improved soft tissue healing, and better bone preservation

ViTab Transformer Framework for Predicting Induced Electric Field and Focality in Transcranial Magnetic Stimulation

Transcranial magnetic stimulation is an electromagnetic induction-based non-invasive therapeutic technique for neurological diseases. For finding new clinical applications and enhancing the efficacy of TMS in existing neurological disorders, the current study focuses on a deep learning-based prediction model as an alternative to time-consuming electromagnetic (EM) simulation software. The main bottleneck of the existing prediction models is to consider very few input parameters of a standard coil such as coil type and coil position for predicting an output of electric field value. To overcome this limitation, a transformer-based prediction model titled as ViTab transformer is developed in this work to predict electric field (E-max), focality or area of stmulation (S-half), and volume of stimulation (V-half) by considering several input parameters such as sources of MRI images, types of coils, coil position, rate of change of current, brain tissues conductivity, and coil distance from the scalp. The proposed framework consists of a vision and a tab transformer to handle both image and tabular-type data. The prediction performance of the offered model is evaluated in terms of coefficient determination, R2 score, for E-max, V-half, and S-half in the testing phase. The obtained result in terms of R2 score for E-max, V-half, and S-half are found 0.97, 0.87, and 0.90 respectively. The results indicate that the suggested ViTab transformer model can predict electric field as well as focality more accurately than the current state-of-the-art methods. The reduced computational time, as well as efficient prediction accuracy, resembles that ViTab transformer can assist the neuroscientist and neurosurgeon prior to providing superior TMS treatment in near future

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