Monitoring for 89Sr removable contamination is required for incoming DOT-labeled packages and work areas containing radioactivity. However, few nuclear medicine departments are equipped for liquid ...scintillation counting, which is the preferred method for detecting beta emitters. We investigated using a sodium iodide well counter to detect 89Sr through its bremsstrahlung photon production.
We used a manufacturer's 89Sr-chloride solution of known concentration and tested various parameters: type of tube, access of tube contents to air, volume of sample, type of wipe material and counting geometry. Liquid scintillation samples also were obtained.
Initial counting efficiencies were 0.10-0.14 cpm/dpm for small volume (10-microliter) samples. The various parameters tested had either positive or negative effects on the system's efficiency to detect 89Sr. One set of samples, counted over time, demonstrated a calculated mean half-life of 50.8 days, which is similar to the 89Sr reported half-life of 50.5 days. Liquid scintillation samples demonstrated efficiencies of almost 1.0 cpm/dpm and a calculated mean half-life of 50.8 days, both as expected.
This study demonstrates that 89Sr removable contamination can be detected sensitively using a sodium iodide well counter, but special considerations must be made when determining the system's counting efficiency.
Nanomaterials in the size range of 3–50 nm have received increased attention in the last few decades because they exhibit physical properties that are intermediate to those of individual molecules ...and bulk materials. Similarly, ultrasmall nanoparticles (USNPs), with sizes in the 1–3 nm range, exhibit unique properties distinct from those of free molecules and larger-sized nanoparticles. These properties are greatly sensitive to both the composition and size of the particles, and thus, the ability to control the synthesis for both of these variables is of paramount importance. This review summarizes various methods for the synthesis of USNPs of metals, metal oxides, and metal chalcogenides as well as recent advances in the development of unique characterization methods for these USNPs. Last is a discussion of several novel applications of USNPs in biomedical imaging, catalysis, and semiconductor development, all of which benefit from the large surface-to-volume ratio and/or other characteristic properties inherent in USNPs.
The recent outbreak of Zika virus (ZIKV) infection in the Americas and its devastating impact on fetal development have prompted the World Health Organization (WHO) to declare the ZIKV pandemic as a ...Public Health Emergency of International Concern. Rapid and reliable diagnostics for ZIKV are vital because ZIKV-infected individuals display no symptoms or nonspecific symptoms similar to other viral infections. Because immunoassays lack adequate sensitivity and selectivity and are unable to identify active state of infection, molecular diagnostics are an effective means to detect ZIKV soon after infection and throughout pregnancy. We report on a highly sensitive reverse-transcription loop-mediated, isothermal amplification (RT-LAMP) assay for rapid detection of ZIKV and its implementation in a simple, easy-to-use, inexpensive, point-of-care (POC) disposable cassette that carries out all the unit operations from sample introduction to detection. For thermal control of the cassette, we use a chemically heated cup without a need for electrical power. Amplification products are detected with leuco crystal violet (LCV) dye by eye without a need for instrumentation. We demonstrated the utility of our POC diagnostic system by detecting ZIKV in oral samples with sensitivity of 5 plaque-forming units (PFU) in less than 40 min. Our system is particularly suitable for resource-poor settings, where centralized laboratory facilities, funds, and trained personnel are in short supply, and for use in doctors’ offices, clinics, and at home.
•Chemical aspects of the ligands design for nanomaterial synthesis and assembly.•The effect of surface ligands on physical and chemical properties of nanomaterials.•The effect of ligands on nano–bio ...interface.•The role of surface ligands on colloidal stability, biocompatibility and multifunctionality of nanomaterials for biomedical applications.
Nanotechnology has received extraordinary attention recently due to its burgeoning role in biomedical science. The materials composing the nanoparticles produce fascinating and diverse functionalities as a result of their exceptionally small size. In fact, even seemingly insignificant changes in particle size can have profound effects on these properties. Thus size control, both during synthesis and in particle suspensions, is a sine qua non for functionality. This can be accomplished by masking the particle surface with a multitude of different ligands. Not only can surface ligands constrain the growth of nucleation, they can also direct the shape of crystallization. However no single ligand can do everything. Fortunately ligands are essentially fungible and can be exchanged at various times to confer the desired properties to the particle. This can include protecting the particle from harsh aqueous conditions, such as pH extremes, maximizing optical properties for diagnostics or shielding the particle from potentially hostile conditions found in the body. Because these moieties interact ubiquitously with various biological materials, particularly proteins, there needs to be a rationalized design of surface ligands. The design of the ligand can have crucial effects on biodistribution as well as evasion of biological defenses. Ligands can even be designed to provide new functionality in response to various environmental stimuli to improve their therapeutic or diagnostic capabilities. Considering the importance of ligands then on this emerging field, this review will thoroughly consider the ligand design for the various steps of nanodevelopment, from synthesis and assembly through biomedical translation.
The purpose of this study was to investigate the cause of a nonuniformity artifact seen on an intrinsic flood.
Intrinsic floods were acquired on three different cameras using a point source in a 1-cc ...syringe, with and without a needle attached. Floods were obtained with the syringe placed perpendicular and parallel to the camera face.
A nonuniformity artifact was evident if a syringe with a needle was placed perpendicular to the crystal face.
If a syringe is used as a point source during the acquisition of an intrinsic quality control flood, the needle should not be placed perpendicular to the camera face.
Context
Three‐dimensional (3‐D) visualisation in anatomical education has been shown to be broadly beneficial for students. However, there is limited research on the relative efficacy of 3‐D ...modalities. This study compares knowledge performance, mental effort and instructional efficiency between autostereoscopic 3‐D visualisation (holograms), monoscopic 3‐D visualisation (3‐DPDFs) and a control (2‐D printed images).
Methods
A cardiac anatomy model was used to generate holograms, 3‐DPDFs and 2‐D printed images. Nursing student participants (n = 179) were randomised into three groups: holograms (n = 60), 3‐DPDFs (n = 60) and printed images (n = 59). Participants completed a pre‐test followed by a self‐study period using the anatomical visualisation. Afterwards, participants completed the NASA‐Task Load Index (NASA‐TLX) cognitive load instrument and a knowledge post‐test.
Results
Post‐test results showed participants studying with holograms (median = 80.0, interquartile range IQR = 66.7–86.7) performed significantly better regarding cardiac anatomy knowledge than participants using 3‐DPDF (median = 66.7, IQR = 53.3–80.0, p = 0.008) or printed images (median = 66.7, IQR = 53.3–80.0, p = 0.007). Mental effort scores, on a scale from 1 to 20, showed hologram (mean = 4.9, standard deviation SD = 3.56) and 3‐DPDF participants (mean = 4.9, SD = 3.79) reported significantly lower cognitive load than printed images (mean = 7.5, SD = 4.9, p < 0.005). Instructional efficiency (E) of holograms (E = 0.35) was significantly higher than printed images (E = −0.36, p < 0.001), although not significantly higher than 3‐DPDF (E = 0.03, p = 0.097).
Conclusions
Participants using holograms demonstrated significant knowledge improvement over printed images and monoscopic 3‐DPDF models, suggesting additional depth cues from holographic visualisation provide benefit in understanding spatial anatomy. Mental effort scores and instructional efficiency of holograms indicate holograms are a cognitively efficient instructional medium. These findings highlight the need for further study of novel 3‐D technologies and learning performance.
Hackett and Proctor use holograms to demonstrate the importance of depth when striving to learn spatial anatomy
Several lines of study suggest that peripheral metabolism of amyloid beta (Aß) is associated with risk for Alzheimer disease (AD). In blood, greater than 90% of Aß is complexed as an apolipoprotein, ...raising the possibility of a lipoprotein-mediated axis for AD risk. In this study, we report that genetic modification of C57BL/6J mice engineered to synthesise human Aß only in liver (hepatocyte-specific human amyloid (HSHA) strain) has marked neurodegeneration concomitant with capillary dysfunction, parenchymal extravasation of lipoprotein-Aß, and neurovascular inflammation. Moreover, the HSHA mice showed impaired performance in the passive avoidance test, suggesting impairment in hippocampal-dependent learning. Transmission electron microscopy shows marked neurovascular disruption in HSHA mice. This study provides causal evidence of a lipoprotein-Aß /capillary axis for onset and progression of a neurodegenerative process.
We define a class of machine-learned flow-based sampling algorithms for lattice gauge theories that are gauge invariant by construction. We demonstrate the application of this framework to U(1) gauge ...theory in two spacetime dimensions, and find that, at small bare coupling, the approach is orders of magnitude more efficient at sampling topological quantities than more traditional sampling procedures such as hybrid Monte Carlo and heat bath.
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