bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimating HIV incidence in the Akwa Ibom AIDS indicator survey (AKAIS), Nigeria using the limiting antigen avidity recency assay
Authors: Negedu‐Momoh Olubunmi R , Balogun Oluseyi , Dafa Ibrahim , Etuk Akan , Oladele Edward Adekola , Adedokun Oluwasanmi , James Ezekiel , Pandey Satish R , Khamofu Hadiza , Badru Titi , Robinson Janet , Mastro Timothy D , Torpey Kwasi 
Published: February 2021

AbstractIntroductionHIV incidence estimates are important to characterize the status of an epidemic, identify locations and populations at high risk and to guide and evaluate HIV prevention interventions. We used the limiting antigen avidity assay (LAg) as part of a recent infection testing algorithm to estimate HIV incidence in the Akwa Ibom AIDS Indicator Survey (AKAIS), Nigeria.MethodsIn 2017, AKAIS, a cross‐sectional population‐based study was conducted at the household (HH) level in 31 local government areas (LGAs) of Akwa Ibom state. Of the 8963 participants aged ≥15 years who were administered questionnaires for demographic and behavioural data, 8306 consented to HIV rapid testing. Whole‐blood specimens were collected from 394 preliminary HIV‐seropositive individuals for CD4+ cell count determination and plasma storage. Samples were shipped to a central quality laboratory for HIV confirmatory testing and viral load determination. A total of 370 HIV‐positive specimens were tested for the recent HIV infection using the LAg assay.ResultsOf the 8306 consenting adults, the HIV prevalence was 4.8%. Of the 370 HIV‐positive samples tested for HIV recency, the median age was 35 years, 48.8% had CD4+ cell count >500/mm3 and 81.3% was not virally suppressed. Viral suppression was greater among females (21%) than for males (13%). A total of 11 specimens were classified as recent based on the LAg assay and HIV viral load ≥1000 copies/mL. The weighted, adjusted HIV‐1 incidence was 0.41/100 person‐years (95% CI 0.16 to 0.66); translating to 13,000 new cases of HIV infections annually in Akwa Ibom, a state with a population of 5.5 million. The HIV incidence rate was similar in females and males (0.41% and 0.42% respectively). The incidence rate was the highest among participants aged 15 to 49 years (0.44%, 95% CI 0.15 to 0.74) translating to 11,000 new infections annually, about 85% of all new infections in the state.ConclusionsThe finding of the high HIV incidence among the 15 to 49‐year age group calls for renewed and innovative efforts to prevent HIV infection among young adults in Akwa Ibom state.
Examining healthcare transition experiences among youth living with HIV in Atlanta, Georgia, USA: a longitudinal qualitative study
Authors: Halyard Alexis S , Doraivelu Kamini , Camacho‐González Andrés F , del Río Carlos , Hussen Sophia A 
Published: February 2021

AbstractIntroductionVirtually all youth living with HIV in paediatric/adolescent care must eventually transition to adult‐oriented HIV care settings. To date, there is limited evidence examining the perspectives of youth living with HIV longitudinally through the healthcare transition process. The objective of our study was to examine attitudes and experiences of youth living with HIV regarding healthcare transition, including potential change in attitudes and experiences over time.MethodsWe conducted a longitudinal qualitative interview study within a large, comprehensive HIV care centre in Atlanta, Georgia, USA between August 2016 and October 2019.We interviewed 28 youth living with HIV as part of a longitudinal observational cohort study of youth undergoing healthcare transition. We conducted qualitative interviews both immediately prior to, and one year following the transition from paediatric to adult‐oriented care.ResultsSix distinct themes emerged from interviews conducted with youth living with HIV pre‐transition: (1) reluctance to transition; (2) paediatric spaces as welcoming, and adult spaces as unwelcoming; (3) varying levels of preparation for transition; and (4) expectation of autonomy in the adult clinic. Analysis of post‐transition interviews with the same youth demonstrated: (1) inconsistencies in the transition experience; (2) fear and anxiety about transition quelled by experience; (3) varying reactions to newfound autonomy and (4) communication as the most valuable facilitator of successful transition.ConclusionsThis study’s longitudinal perspective on the healthcare transition experience yields insights that can be incorporated into programming targeting this critically important population. Although our study was conducted in a USA‐based clinic with co‐located paediatric and adult care services, many of our findings are likely to have relevance in other settings as well. Interventions aiming to improve HIV care engagement through transition should seek to enhance patient–provider communication in both paediatric and adult clinics, improve preparation of patients in paediatric clinics and ease patients gradually into autonomous disease management.
Computational analysis of the clinical presentation of a ligamentous Lisfranc injury
Authors: Perez M. Tyler , Owen John R. , Wayne Jennifer S. 
Published: February 2021

AbstractLisfranc injuries in the midfoot disrupt key arches of the foot which, if left untreated, can progress to pain, dysfunction, and arthritis. A clinical challenge is that 30–40% of Lisfranc injuries are missed in initial evaluations. The objective of this study was to explore different conditions of limb loading that could influence the biomechanics of the Lisfranc joint in a validated computational model. A computational model was created using SolidWorks software to represent the bones and soft tissues of the lower leg and foot. The model was compared to a cadaveric study of healthy and injured Lisfranc joints. The model was then used to simulate weight‐bearing radiographs and evaluate how muscle activity and foot position impacted the diastasis of the Lisfranc joint, a key indicator used to diagnose Lisfranc injuries. The computational model was within one standard deviation of the cadaveric study in all measurements for the healthy and injured foot. When simulating weight‐bearing radiographs, the presence of muscle activity or inversion/eversion resulted in less joint separation for the model with ligamentous Lisfranc injuries. While previous research has noted that weight‐bearing radiographs provide better conditions to assess Lisfranc injuries than nonweight‐bearing, this study suggests that in weight‐bearing radiographs both altering the position of the foot, possibly due to pain, and the active contraction of the extrinsic flexor muscles can obfuscate indications of a Lisfranc injury.
In Situ Formation of 3D Conductive and Cell‐Laden Graphene Hydrogel for Electrically Regulating Cellular Behavior
Authors: Chen Xuelong , Ranjan Vivek Damodar , Liu Sijun , Liang Yen Nan , Lim Jacob Song Kiat , Chen Hui , Hu Xiao , Zhang Yilei 
Published: February 2021

AbstractElectroconductive and injectable hydrogels are attracting increasing attention owing to the needs of electrically induced regulation of cell behavior, tissue engineering of electroactive tissues, and achieving minimum invasiveness during tissue repair. In this study, a novel in situ formed 3D conductive and cell‐laden hydrogel is developed, which can be broadly used in bioprinting, tissue engineering, neuroengineering etc. An instantaneous, uniform spatial distribution and encapsulation of cells can be achieved as a result of hydrogen bonding induced hydrogel formation. Particularly, the cell‐laden hydrogel can be easily obtained by simply mixing and shaking the polydopamine (PDA) functionalized rGO (rGO‐PDA) with polyvinyl alcohol (PVA) solution containing cells. Graphene oxide is reduced and functionalized by dopamine to restore the electrical conductivity, while simultaneously enhancing both hydrophilicity and biocompatibility of reduced graphene oxide. In vitro culture of PC12 cells within the cell‐laden hydrogel demonstrates its biocompatibility, noncytotoxicity as well as the ability to support long‐term cell growth and proliferation. Enhanced neuronal differentiation is also observed, both with and without electrical stimulation. Overall, this 3D conductive, cell‐laden hydrogel holds great promise as potential platform for tissue engineering of electroactive tissues.
Tracking 3D ultrasound anatomical landmarks via three orthogonal plane‐based scale discriminative correlation filter network
Authors: Huang Yibin , He Jishuai , Wu Xu , Zhao Xiaozhi , Wu Jian 
Published: February 2021

PurposeIn abdominal interventional therapy, accurate motion tracking of the target is regarded as crucial to minimize trauma and optimize dosage delivery. Meanwhile, three‐dimensional (3D) ultrasound (US) is an attractive modality to show the real‐time motion pattern of the target. In this work, we developed an accurate and robust landmark tracking algorithm for 3D US sequences.MethodsThe proposed algorithm introduces a three orthogonal planes (TOPs) based scale discriminative correlation filter network for 3D US landmarks tracking. First, we couple the fully convolutional network (FCN) with scale discriminative correlation filter (SDCF) to generate an effective tracker. And SDCF is reformulated as a differentiable layer, which ensures the network can perform scale learning and end‐to‐end training. Next, we train the end‐to‐end network on millions of natural images. Finally, we convert 3D US image to 2D three‐channel image by TOP transformation and feed them to the proposed network for performing online tracking.ResultsOnline tracking performance was evaluated on the Challenge of Liver Ultrasound Tracking (CLUST) dataset with 22 sets of 3D US sequences, obtaining mean error of 1.63 ± 1.04 mm and 95th percentile (95%ile) error of 3.37 mm, when compared with manual annotations annotated by surgeons. Ablation study indicates that the promising results benefit from SDCF and scale learning, which alleviates the influence from deformation. The findings of the clinical analysis support that the proposed algorithm can work well with different initial patch sizes, which means that our algorithm has potential to lighten the burden of surgeons.ConclusionsWe propose a flexible, accurate and robust landmark tracking algorithm for the image‐guided interventions, and our algorithm is comparable with the state‐of‐the‐art approaches. The tracking accuracy and robustness show that our algorithm has potential in 3D US‐guided abdominal interventional therapies. Furthermore, more researches are needed to improve the computing speed of the algorithm to achieve real‐time tracking.
Technical Note: Small field dose correction factors for radiochromic film in lung phantoms
Authors: Charles Paul.H. , Crowe Scott.B. , Kairn Tanya 
Published: February 2021

PurposeRadiochromic film has been established as a detector that can be used without the need for perturbation correction factors for small field dosimetry in water. However, perturbation factors in low density media such as lung have yet to be published. This study calculated the factors required to account for the perturbation of radiochromic film when used for small field dosimetry in lung equivalent material.MethodMonte Carlo simulations were used to calculate dose to Gafchromic EBT3 film when placed inside a lung phantom. The beam simulated had a nominal energy of 6 MV and the field sizes simulated ranged from 10 × 10 mm2 to 30 × 30 mm2. The lung density simulated was varied between 0.2 and 0.3 g/cm3. Each simulation was repeated with the film replaced by lung material (the same as the surrounding medium), and the required correction factors for film dosimetry in lung () were calculated by dividing the dose in lung by the dose in film.ResultsFor field sizes 30 × 30 mm2 and larger, no correction factors were required. At a 20 × 20 mm2 field size, small corrections were required, but were within the approximate accuracy of film dosimetry (~2%). For a 10 × 10 mm2 field size, significant correction factors need to be applied (0.935 for lung density of 0.20 g/cm3 to 0.963 for lung density of 0.30 g/cm3). The values lower than one mean that the film is over‐responding. At the “upstream” lung‐water interface the correction factors were close to unity; while at the downstream interface the corrections required were marginally smaller to those at the center of lung. One centimeter or more away from the interfaces, the correction factor did not vary as a function distance from the interface (in the beam direction). Away from the central axis (perpendicular to the beam direction), the correction factors increased slightly (away from unity) as a function of off‐axis distance, before abruptly changing direction at the penumbra, with the film actually under‐responding by ~10% outside the field edges.ConclusionAccurate dosimetry of very small fields (15 × 15 mm2 or smaller) using radiochromic film requires correction factors for the perturbation of the film on the surrounding lung material. This correction factor was as high as 6.5% for a 10 × 10 mm2 field size and a density of 0.2 g/cm3. This will increase if either the density or the field size decrease further. This correction factor does not vary as a function of depth in lung once charged particle equilibrium is established.
On the impact of absorbed dose specification, tissue heterogeneities, and applicator heterogeneities on Monte Carlo‐based dosimetry of Ir‐192, Se‐75, and Yb‐169 in conventional and intensity‐modulated brachytherapy for the treatment of cervical cancer
Authors: Morcos Marc , Viswanathan Akila N. , Enger Shirin A. 
Published: February 2021

PurposeThe purpose of this study was to evaluate the impact of dose reporting schemes and tissue/applicator heterogeneities for 192Ir‐, 75Se‐, and 169Yb‐based MRI‐guided conventional and intensity‐modulated brachytherapy.Methods and MaterialsTreatment plans using a variety of dose reporting and tissue/applicator segmentation schemes were generated for a cohort (n = 10) of cervical cancer patients treated with 192Ir‐based Venezia brachytherapy. Dose calculations were performed using RapidBrachyMCTPS, a Geant4‐based research Monte Carlo treatment planning system. Ultimately, five dose calculation scenarios were evaluated: (a) dose to water in water (Dw,w); (b) Dw,w taking the applicator material into consideration (Dw,wApp); (c) dose to water in medium (Dw,m); (d and e) dose to medium in medium with mass densities assigned either nominally per structure (Dm,m (Nom)) or voxel‐by‐voxel (Dm,m).ResultsIgnoring the plastic Venezia applicator (Dw,wApp) overestimates Dm,m by up to 1% (average) with high energy source (192Ir and 75Se) and up to 2% with 169Yb. Scoring dose to water (Dw,wApp or Dw,m) generally overestimates dose and this effect increases with decreasing photon energy. Reporting dose other than Dm,m (or Dm,m Nom) for 169Yb‐based conventional and intensity‐modulated brachytherapy leads to a simultaneous overestimation (up to 4%) of CTVHR D90 and underestimation (up to 2%) of bladder D2cc due to a significant dip in the mass‐energy absorption ratios at the depths of nearby targets and OARs. Using a nominal mass‐density assignment per structure, rather than a CT‐derived voxel‐by‐voxel assignment for MRI‐guided brachytherapy, amounts to a dose error up to 1% for all radionuclides considered.ConclusionsThe effects of the considered dose reporting schemes trend correspondingly between conventional and intensity‐modulated brachytherapy. In the absence of CT‐derived mass densities, MRI‐only‐based dosimetry can adequately approximate Dm,m by assigning nominal mass densities to structures. Tissue and applicator heterogeneities do not significantly impact dosimetry for 192Ir and 75Se, but do for 169Yb; dose reporting must be explicitly defined since Dw,m and Dw,w may overstate the dosimetric benefits.
Myofiber strain in healthy humans using DENSE and cDTI
Authors: Moulin Kévin , Croisille Pierre , Viallon Magalie , Verzhbinsky Ilya A. , Perotti Luigi E. , Ennis Daniel B. 
Published: February 2021

AbstractPurposeMyofiber strain, Eff, is a mechanistically relevant metric of cardiac cell shortening and is expected to be spatially uniform in healthy populations, making it a prime candidate for the evaluation of local cardiomyocyte contractility. In this study, a new, efficient pipeline was proposed to combine microstructural cDTI and functional DENSE data in order to estimate Eff in vivo.MethodsThirty healthy volunteers were scanned with three long‐axis (LA) and three short‐axis (SA) DENSE slices using 2D displacement encoding and one SA slice of cDTI. The total acquisition time was 11 minutes ± 3 minutes across volunteers. The pipeline first generates 3D SA displacements from all DENSE slices which are then combined with cDTI data to generate a cine of myofiber orientations and compute Eff. The precision of the post‐processing pipeline was assessed using a computational phantom study. Transmural myofiber strain was compared to circumferential strain, Ecc, in healthy volunteers using a Wilcoxon sign rank test.ResultsIn vivo, computed Eff was found uniform transmurally compared to Ecc (−0.14[−0.15, −0.12] vs −0.18 [−0.20, −0.16], P < .001, −0.14 [−0.16, −0.12] vs −0.16 [−0.17, −0.13], P < .001 and −0.14 [−0.16, −0.12] vs Ecc_C = −0.14 [−0.15, −0.11], P = .002, Eff_C vs Ecc_C in the endo, mid, and epi layers, respectively).ConclusionWe demonstrate that it is possible to measure in vivo myofiber strain in a healthy human population in 10 minutes per subject. Myofiber strain was observed to be spatially uniform in healthy volunteers making it a potential biomarker for the evaluation of local cardiomyocyte contractility in assessing cardiovascular dysfunction.
Using a Microsimulation of Energy Balance to Explore the Influence of Prenatal Sugar‐Sweetened Beverage Intake on Child BMI
Authors: Kasman Matt , Heuberger Benjamin , Mack‐Crane William , Purcell Rob , Hammond Ross A. , Oken Emily , Kleinman Ken P. 
Published: February 2021

ObjectiveExperiments with animals suggest that high sugar consumption during pregnancy may predispose offspring to obesity, but few human studies have examined this relationship. This study explored the association between the consumption of sugar‐sweetened beverages (SSBs) during pregnancy and caloric intake through childhood.MethodsUsing cohort data on child weight, height, and physical activity levels, a lab‐validated microsimulation model of energy balance was employed to infer the caloric intake of children through age 11 years. Random effects models were then employed to explore the relationships between prenatal maternal consumption and inferred caloric intake during childhood.ResultsAn additional daily serving of SSBs during the second trimester of pregnancy was associated with an increase in child consumption of 13 kcal/d (95% CI: 1.2‐26.8). Age‐stratified models adjusting for maternal and child covariates suggested that this association was strongest for children aged 2.5 to 5.5 years. The consumption of SSBs during the first trimester was not found to have a consistently positive relationship to caloric intake.ConclusionsThese findings suggest that SSB consumption during the second trimester of pregnancy is associated with child energy intake and may influence anthropometry in early childhood, which is consistent with and suggestive of the presence of biological causal pathways alongside likely simultaneous contributions of social and environmental influences.
Modified resol type phenolic resin nanocomposites as surface metal coatings
Authors: Ahmed Sahar , Mohamed Moshera , Mansour Nahla , El‐Komy Doaa , Sadek Elham 
Published: February 2021

AbstractNanocomposites based on resol resin as a matrix and prepared organoclay, from Egyptian bentonite clay, as reinforcement material were synthesized. The effect of organoclay content (i.e., 0.5, 1.0, 1.5, 2.0, and 2.5 phr) on the properties of the prepared samples with respect to the prepared composites and resol resin with no clay was investigated. The prepared samples with higher organoclay content (i.e., 2.0 phr) were modified with epoxy or/and urethane resin and characterized using transmission electron microscope (TEM), X‐ray diffraction (XRD), and Fourier transform infrared measurements (FTIR). TEM showed uniform dispersion of the clay while XRD showed exfoliated structures. FTIR measurements confirmed the bond formation between epoxy or/and diisocynate with phenolic hydroxyl groups of resol resin. Mechanical properties, chemical resistance, thermal properties, and electrical volume resistivity were studied. Results showed that epoxy modified resol resin film samples with 2.0 phr organoclay exhibited higher adhesion and scratch hardness values, higher chemical resistance, thermal stability, and lower electrical conductivity compared with mixed epoxy/urethane and urethane samples as well as unmodified resol resin nanocomposite film samples. The samples could be useful as surface metal coatings.
'Smart' light‐reflective windows based on temperature responsive twisted nematic liquid crystal polymers
Authors: Kragt Augustinus J. J. , Loonen Roel C. G. M. , Broer Dirk J. , Debije Michael G. , Schenning Albert P. H. J. 
Published: February 2021

Abstract'Smart' windows which reversibly increase their reflectivity upon heating are attracting considerable attention as devices for maintaining comfortable indoor environmental conditions. In this work, twisted nematic semi‐interpenetrating liquid crystal networks which lose their order upon heating are sandwiched between reflective linear polarizers. This 'smart' window reversibly decreases its transmission from about 50–10% over a wavelength range between 400 and 1100 nm upon heating, resulting in the window becoming darker and reflecting more light. This 'smart' window is potentially interesting for energy saving window applications where variation between privacy and visible light transparency states is required.
The STI1‐domain is a flexible alpha‐helical fold with a hydrophobic groove
Authors: Fry Michelle Y. , Saladi Shyam M. , Clemons William M. 
Published: February 2021

AbstractSTI1‐domains are present in a variety of co‐chaperone proteins and are required for the transfer of hydrophobic clients in various cellular processes. The domains were first identified in the yeast Sti1 protein where they were referred to as DP1 and DP2. Based on hidden Markov model searches, this domain had previously been found in other proteins including the mammalian co‐chaperone SGTA, the DNA damage response protein Rad23, and the chloroplast import protein Tic40. Here, we refine the domain definition and carry out structure‐based sequence alignment of STI1‐domains showing conservation of five amphipathic helices. Upon examinations of these identified domains, we identify a preceding helix 0 and unifying sequence properties, determine new molecular models, and recognize that STI1‐domains nearly always occur in pairs. The similarity at the sequence, structure, and molecular levels likely supports a unified functional role.