Search

Background: Adherence challenges with oral tenofovir-based pre-exposure prophylaxis (PrEP) are common. We developed a point-of-care assay to objectively assess tenofovir in urine and conducted a pilot trial examining the impact of counselling informed by use of this urine assay on long-term PrEP adherence., Methods: This randomised trial enrolled women not in serodiscordant partnerships 3 months after PrEP initiation at the Kenya Medical Research Institute to compare standard-of-care adherence counselling versus counselling informed by the urine assay (urine-test counselling group) every 3 months for 12 months. In the standard of care group, urine samples were stored and tested at study end without participant feedback. Here we report the adherence primary outcome of hair concentrations of tenofovir at 12 months as a long-term metric (undetectable levels defined long-term non-adherence), as well as urine concentrations of tenofovir at each visit as a short-term adherence metric and acceptability of the assay assessed by quantitative surveys. Data were analysed by randomisation group. This completed trial was registered with ClinicalTrials.gov (NCT03935464)., Findings: From March 17, 2021 to Jan 18, 2022 we enrolled 49 women in the urine-test counselling group and 51 in the standard of care group; retention was 86 (86%) of 100. Nine (21%) of 42 in the urine-test counselling group had hair samples at 12 months with tenofovir concentrations below the limit of quantification compared with 15 (37%) of 41 in the standard of care group. The relative odds of long-term non-adherence in the standard of care group compared with urine-test counselling were 3·53 (95% CI 1·03-12·03; p=0·044). Pre-intervention, urine tenofovir was detectable in 65% in the urine-test counselling group and 71% in the standard of care group (p=0·68). At 12 months, 31 (72%) of 43 in the intervention group had detectable urine tenofovir compared with 19 (45%) of 42 in the standard of care group (p=0·0015). 40 (93%) of 43 participants liked the test very much and only one disliked the test. One participant in the standard of care group was withdrawn at the 6-month visit due to HIV seroconversion., Interpretation: A low-cost urine tenofovir assay to inform PrEP counselling resulted in improvement in both short-term and long-term metrics of adherence. This urine tenofovir assay could help to improve long-term PrEP adherence., Funding: National Institute of Allergy and Infectious Diseases and National Institutes of Health., Competing Interests: Declaration of interests MG's Hair Analytical Laboratory co-owns the patent on the antibody directed against tenofovir with Abbott Laboratories. DVG has received consulting fees from Gilead Sciences. Beyond receiving National Institutes of Health grants which provide support to KN's institution, KN has received additional grant funding from the Bill & Melinda Gates Foundation, United States Agency for International Development, and Merck Pharmaceuticals. All other authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Group-III nitrides have transformed solid-state lighting and are strategically positioned to revolutionize high-power and high-frequency electronics. To drive this development forward, a deep understanding of fundamental material properties, such as charge carrier behavior, is essential and can also unveil new and unforeseen applications. This underscores the necessity for novel characterization tools to study group-III nitride materials and devices. The optical Hall effect (OHE) emerges as a contactless method for exploring the transport and electronic properties of semiconductor materials, simultaneously offering insights into their dielectric function. This non-destructive technique employs spectroscopic ellipsometry at long wavelengths in the presence of a magnetic field and provides quantitative information on the charge carrier density, sign, mobility, and effective mass of individual layers in multilayer structures and bulk materials. In this paper, we explore the use of terahertz (THz) OHE to study the charge carrier properties in group-III nitride heterostructures and bulk material. Examples include graded AlGaN channel high-electron-mobility transistor (HEMT) structures for high-linearity devices, highlighting the different grading profiles and their impact on the two-dimensional electron gas (2DEG) properties. Next, we demonstrate the sensitivity of the THz OHE to distinguish the 2DEG anisotropic mobility parameters in N-polar GaN/AlGaN HEMTs and show that this anisotropy is induced by the step-like surface morphology. Finally, we present the temperature-dependent results on the charge carrier properties of 2DEG and bulk electrons in GaN with a focus on the effective mass parameter and review the effective mass parameters reported in the literature. These studies showcase the capabilities of the THz OHE for advancing the understanding and development of group-III materials and devices.

Background: In 2020, healthcare providers were expected to provide care to individuals with coronavirus disease 2019 (COVID-19), putting them at risk of acquiring COVID-19. The possibility of acquiring poorly understood infectious diseases while providing care may have an impact on the mental health of providers. We conducted a study to explore the effects of COVID-19 on the mental health of healthcare providers., Methods: Between April and August 2021, we conducted in-depth interviews with 60 healthcare providers in the infectious disease unit (IDU) and other units of the hospital (non-IDU). The healthcare providers completed an online self-administered survey form with demographic data (age, sex, average income, and known contact with a COVID-19 patient). We used semi-structured interview guides to understand the healthcare providers' lived experiences of stress, anxiety, depression, and their associated factors. We transcribed the interviews verbatim and coded and analyzed the transcripts to derive thematic concepts related to mental health experiences., Results: The healthcare providers had a median age of 37 years [IQR 20.0-58.0], and 56.7% were female, 30.0% nurses, 18.3% medical doctors, and 11.7% laboratory technologists. The healthcare providers reported increased stress during the pandemic, attributed to the high demand for patient care, changes in social life, and fear of COVID-19 infection. They also reported experiences of anxiety and depression as a result of limited knowledge at the beginning of the pandemic and the perception that "COVID-19 resulted in death". Testing positive for COVID-19, high exposure to COVID-19 risks, and the death of patients and colleagues reportedly affected the healthcare providers' mental health. Additionally, the healthcare providers reported mental health support through debriefing meetings, peer-to-peer support, and psychological counseling, with privacy and confidentiality concerns., Conclusions: Healthcare providers faced mental health issues such as stress and anxiety while taking care of COVID-19 patients. An effective mental health response requires institutional practices that address context-specific challenges such as privacy and confidentiality.

Introduction: Delivery of oral pre-exposure prophylaxis (PrEP) is being scaled up in Africa, but clinic-level barriers including lengthy clinic visits may threaten client continuation on PrEP., Methods: Between January 2020 and January 2022, we conducted a quasi-experimental evaluation of differentiated direct-to-pharmacy PrEP refill visits at four public health HIV clinics in Kenya. Two clinics implemented the intervention package, which included direct-to-pharmacy for PrEP refill, client HIV self-testing (HIVST), client navigator, and pharmacist-led rapid risk assessment and dispensing. Two other clinics with comparable size and client volume served as contemporaneous controls with the usual clinic flow. PrEP continuation was evaluated by visit attendance and pharmacy refill records, and time and motion studies were conducted to determine time spent in the clinics. Dried blood spots were collected to test for tenofovir-diphosphate (TFV-DP) at random visits. We used logistic regression to assess the intervention effect on PrEP continuation and the Wilcoxon rank sum test to assess the effect on clinic time., Results: Overall, 746 clients were enrolled, 366 at control clinics (76 during pre-implementation and 290 during implementation phase), and 380 at direct-to-pharmacy clinics (116 during pre-implementation and 264 during implementation phase). Prior to implementation, the intervention and control clinics were comparable on client characteristics (female: 51% vs. 47%; median age: 33 vs. 33 years) and PrEP continuation (35% vs. 37% at 1 month, and 37% vs. 39% at 3 months). The intervention reduced total time spent at the clinic by 35% (median of 51 minutes at control vs. 33 minutes at intervention clinics; p<0.001), while time spent on HIV testing (20 vs. 20 minutes; p = 0.50) and pharmacy (8 vs. 8 minutes; p = 0.8) was unchanged. PrEP continuation was higher at intervention versus the control clinics: 45% versus 33% at month 1, 34% versus 25% at month 3 and 23% versus 16% at month 6. TFV-DP was detected in 85% (61/72) of samples, similar by the study group (83% vs. 85%)., Conclusions: A client-centred PrEP delivery approach with direct-to-pharmacy PrEP refill visits plus client HIVST significantly reduced clinic visit time by more than one-third and improved PrEP continuation in public health HIV clinics in Kenya., (© 2024 The Authors. Journal of the International AIDS Society published by John Wiley & Sons Ltd on behalf of International AIDS Society.)

HIV self-testing (HIVST) has the potential to reduce barriers associated with clinic-based preexposure prophylaxis (PrEP) delivery. We conducted a substudy nested in a prospective, pilot implementation study evaluating patient-centered differentiated care services. Clients chose either a blood-based or oral fluid HIVST kit at the first refill visit. Data were abstracted from program files and surveys were administered to clients. We purposively sampled a subset of PrEP clients and their providers to participate in in-depth interviews. We surveyed ( n  = 285). A majority (269/285, 94%) reported HIV risk. Blood-based HIVST was perceived as easy to use (76/140, 54%), and (41/140, 29%) perceived it to be more accurate. Oral fluid-based HIVST was perceived to be easy to use (95/107, 89%), but almost all (106/107, 99%) perceived it as less accurate. HIVST improved privacy, reduced workload, and saved time. HIVST demonstrates the potential to streamline facility-based PrEP care in busy African public health facilities., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Terahertz (THz) technologies provide opportunities ranging from calibration targets for satellites and telescopes to communication devices and biomedical imaging systems. A main component will be broadband THz absorbers with switchability. However, optically switchable materials in THz are scarce and their modulation is mostly available at narrow bandwidths. Realizing materials with large and broadband modulation in absorption or transmission forms a critical challenge. This study demonstrates that conducting polymer-cellulose aerogels can provide modulation of broadband THz light with large modulation range from ≈ 13% to 91% absolute transmission, while maintaining specular reflection loss < -30 dB. The exceptional THz modulation is associated with the anomalous optical conductivity peak of conducting polymers, which enhances the absorption in its oxidized state. The study also demonstrates the possibility to reduce the surface hydrophilicity by simple chemical modifications, and shows that broadband absorption of the aerogels at optical frequencies enables de-frosting by solar-induced heating. These low-cost, aqueous solution-processable, sustainable, and bio-friendly aerogels may find use in next-generation intelligent THz devices., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Few studies have focused on understanding pre-exposure prophylaxis (PrEP) non-initiation among young, high-risk women in sub-Saharan Africa. This study aimed to qualitatively explore why young women in Kenya at high-risk for HIV chose not to enroll in a PrEP adherence trial. We performed 40 semi-structured interviews with young high-risk women assessing concerns about PrEP and/or study participation. We also assessed community-level factors influencing decision-making around PrEP through 10 focus groups involving peers, young men, caregivers, and community leaders. Our qualitative data reflect the complexity of navigating barriers preventing PrEP initiation in settings where taking PrEP may be perceived as immoral behavior. Framed within the context of risk perception, the decision to start PrEP may run counter to the potential risk of losing support from one's community. Our findings suggest that approaches addressing social norms, while de-medicalizing HIV prevention services, are needed to further increase PrEP uptake among young Kenyan women., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Adherence to oral pre-exposure prophylaxis (PrEP) is challenging, and cellular technology offers a promising opportunity for support. However, a recent randomized controlled trial found that SMS reminders did not improve PrEP adherence. We used qualitative methods to explore the trial participants' experiences with the SMS intervention. We conducted serial in-depth interviews with 54 young Kenyan women, using inductive and deductive content analysis . Initially, SMS reminders were highly acceptable. Participants expressed enthusiasm with receiving the reminders because of the coded nature of the SMS reminders; they also helped in 'habit forming' with daily adherence. However, overtime, participants reported growing concerns about privacy, self-efficacy, and responsibility and SMS fatigue. Participants also reported other challenges, including phone loss, poor telephone network, and lack of electricity. Further research to explore if SMS reminders in alternative formats or with different frequency is needed, in addition to identification of alternate adherence support strategies., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Background: Falls are a common complication experienced after a stroke and can cause serious detriments to physical health and social mobility, necessitating a dire need for intervention. Among recent advancements, wearable airbag technology has been designed to detect and mitigate fall impact. However, these devices have not been designed nor validated for the stroke population and thus, may inadequately detect falls in individuals with stroke-related motor impairments. To address this gap, we investigated whether population-specific training data and modeling parameters are required to pre-detect falls in a chronic stroke population., Methods: We collected data from a wearable airbag's inertial measurement units (IMUs) from individuals with (n = 20 stroke) and without (n = 15 control) history of stroke while performing a series of falls (842 falls total) and non-falls (961 non-falls total) in a laboratory setting. A leave-one-subject-out crossvalidation was used to compare the performance of two identical machine learned models (adaptive boosting classifier) trained on cohort-dependent data (control or stroke) to pre-detect falls in the stroke cohort., Results: The average performance of the model trained on stroke data (recall = 0.905, precision = 0.900) had statistically significantly better recall (P = 0.0035) than the model trained on control data (recall = 0.800, precision = 0.944), while precision was not statistically significantly different. Stratifying models trained on specific fall types revealed differences in pre-detecting anterior-posterior (AP) falls (stroke-trained model's F 1 -score was 35% higher, P = 0.019). Using activities of daily living as non-falls training data (compared to near-falls) significantly increased the AUC (Area under the receiver operating characteristic) for classifying AP falls for both models (P < 0.04). Preliminary analysis suggests that users with more severe stroke impairments benefit further from a stroke-trained model. The optimal lead time (time interval pre-impact to detect falls) differed between control- and stroke-trained models., Conclusions: These results demonstrate the importance of population sensitivity, non-falls data, and optimal lead time for machine learned pre-impact fall detection specific to stroke. Existing fall mitigation technologies should be challenged to include data of neurologically impaired individuals in model development to adequately detect falls in other high fall risk populations. Trial registration https://clinicaltrials.gov/ct2/show/NCT05076565 ; Unique Identifier: NCT05076565. Retrospectively registered on 13 October 2021., (© 2022. The Author(s).)

Nanostructures of conventional metals offer manipulation of light at the nanoscale but are largely limited to static behavior due to fixed material properties. To develop the next frontier of dynamic nano-optics and metasurfaces, this study utilizes the redox-tunable optical properties of conducting polymers, as recently shown to be capable of sustaining plasmons in their most conducting oxidized state. Electrically tunable conducting polymer nano-optical antennas are presented, using nanodisks of poly(3,4-ethylenedioxythiophene:sulfate) (PEDOT:Sulf) as a model system. In addition to repeated on/off switching of the polymeric nanoantennas, the concept enables gradual electrical tuning of the nano-optical response, which was found to be related to the modulation of both density and mobility of the mobile polaronic charge carriers in the polymer. The resonance position of the PEDOT:Sulf nanoantennas can be conveniently controlled by disk size, here reported down to a wavelength of around 1270 nm. The presented concept may be used for electrically tunable metasurfaces, with tunable farfield as well as nearfield. The work thereby opens for applications ranging from tunable flat meta-optics to adaptable smart windows., (© 2022 The Authors. Advanced Materials published by Wiley-VCH GmbH.)