Search Results (2,286)

Background/Objectives: The gastrin-releasing peptide receptor (GRPR) shows high-density expression in prostate cancer (PCa), especially in the early stages of the disease. The introduction of a safe radiotracer for assessing GRPR-expression in PCa may serve as an alternative or complementary tracer to PSMA-directed probes for patients with insufficient PSMA expression. In the present study, the tolerability and safety, biodistribution, and dosimetry of the new GRPR-targeting radiopeptide [^99mTc]Tc-DB8 were investigated for the first time in male PCa patients. A mass escalation study was performed, aiming to improve tumor-to-background contrast and, thereby, to enhance diagnostic accuracy. Methods: Sixteen male patients were enrolled in a single-center diagnostic open-label exploratory Phase I clinical trial. Patients were administered a single intravenous injection of 40, 80, or 120 µg of [^99mTc]Tc-DB8 peptide (n = 5–6) and underwent whole-body planar imaging (anterior and posterior) 2, 4, 6, and 24 h post-injection (pi) and SPECT-CT acquisition 2, 4, and 6 h pi. Results: Administration of [^99mTc]Tc-DB8 was well tolerated at all tested peptide masses. The effective dose did not differ significantly between the injected peptide mass and was 0.005 ± 0.003 mSv/MBq. High activity uptake was observed in the pancreas and kidneys, which 3-fold decreased with an increasing injected peptide mass from 40 to 120 µg. The activity uptake in primary tumors did not differ significantly between cohorts injected with different peptide masses [SUV_max 1.65–9.96]. The tumor-to-muscle ratios increased with time and were the highest for the cohort injected with 120 µg of peptide, 7.2 ± 3.1 (4.64-11-25) at 4 h pi. Conclusions: Single intravenous administration of [^99mTc]Tc-DB8, for visualization of GRPR expression in PCa using SPECT imaging was well tolerated in a peptide mass range of 40–120 µg. An injected peptide mass of 80–120 µg/patient and SPECT acquisition 2–4 h pi were found to be optimal for further clinical studies due to the significantly lower activity accumulation in the pancreas and kidneys. Full article

In this study, core–shell Ln₂O₃@carbon nanoparticles (core = Ln₂O₃ and shell = carbon; Ln = Tb and Ho) were synthesized for the first time by preparing Ln₂O₃ nanoparticles through a polyol method, followed by carbon coating using D-glucose as a carbon precursor in aqueous media. The synthesized Ln₂O₃@carbon nanoparticles exhibited good colloidal stability in solution and very low toxicity in in vitro cellular cytotoxicity tests. They exhibited paramagnetic magnetization values that increased with increasing applied field strength, resulting from spin–orbit magnetic moments of 4f-electrons; hence, they yielded negligible r₁ (<0.1 s⁻¹mM⁻¹) and appreciable r₂ values (3.446 and 3.677 s⁻¹mM⁻¹ for Ln = Tb and Ho, respectively) at 3 T, highlighting their potential as T₂ MRI contrast agents, particularly at high MR fields. In addition, the carbon coating shell exhibited photoluminescence at 460 nm, suitable for applications in fluorescence imaging probes. Full article

Texture testing is applied in various industries. Recently, a simple, accelerometer-equipped texture testing device (Surface Tester of Food Resilience; STFR) has been developed, and we elaborated formulae describing the movement of the probe. In this paper, we describe the validation of said formulae, relying on video image analysis of the travel of the spherical probe. This allowed us to select the best-fit mathematical models. We elaborated formulae for accurate calculation of specimen surface characteristics and present an application integrating these formulae in the test procedure. The impact of correct height adjustment and specimen height was found to be critical for reproducibility of measurements and thus needs attendance. These findings form the basis for future comparative studies with established texture analyzers. Full article

Background/Objectives: Transurethral incision (TUI) is a common procedure for posterior urethral valves (PUV). However, no standardized method has been established to assess its efficacy intraoperatively. In this study, we aimed to develop and evaluate a real-time ultrasound-guided TUI (RUG-TUI) technique. Methods: A single-center, retrospective feasibility study with a cohort design was conducted using historical controls to compare RUG-TUI with standard TUI in children with PUV. Data from patients who underwent RUG-TUI for PUV between April 2021 and July 2022 or TUI without real-time ultrasound guidance between August 2020 and March 2021 (control group) were retrospectively reviewed. A transperineal linear probe provided longitudinal imaging. The diameters of the constricted (C) and expanded (E) portions of the urethra before and after the procedure were measured, and the E/C ratio was calculated. The primary outcome was the duration of postoperative gross hematuria, and the secondary outcomes included changes in the urethral diameter ratio (E/C ratio), intraoperative complications, and residual obstruction on VCUG. Results: The mean duration of post-procedure macroscopic hematuria was significantly shorter in the RUG-TUI group than in the control group (p = 0.049). No massive intraoperative bleeding or sphincter damage occurred. In the RUG-TUI group, the mean diameters of the constricted segment before and after the procedure were 3.0 (±1.0) and 5.7 (±1.2) mm, respectively, while the pre- and postoperative E/C ratios were 1.8 (±0.5) and 0.9 (±0.1), respectively (p < 0.0001). Conclusions: RUG-TUI for PUV enabled visualization of the longitudinal axis of the urethra, allowing assessment of the anatomical relationship between the stenosis and external urethral sphincter. In this retrospective feasibility cohort, RUG-TUI was associated with a shorter duration of postoperative gross hematuria. These exploratory findings suggest that RUG-TUI may support intraoperative evaluation of procedural adequacy. Full article

Senescence is a dynamic, multifaceted process implicated in tissue aging, organ dysfunction, and intricately associated with numerous chronic diseases. As senescent cells accumulate, they drive inflammation, fibrosis, and metabolic disruption through the senescence-associated secretory phenotype (SASP). Despite its clinical relevance, senescence remains challenging to detect non-invasively due to its heterogeneous nature and the lack of universal biomarkers. Recent advances in the development of specific imaging probes for positron emission tomography (PET) enable in vivo visualization of senescence-associated pathways across key organs, such as the lung, heart, kidney, and metabolic processes. For instance, [¹⁸F]FPyGal, a β-galactosidase-targeted tracer, has demonstrated selective accumulation in senescent cells in both preclinical and early clinical studies, while FAP-targeted radioligands are emerging as tools for imaging fibrotic remodeling in the lung, liver, kidney, and myocardium. This review examines a new generation of PET radioligands targeting hallmark features of senescence, with the potential to track and measure the process, the ability to be translated into clinical interventions for early diagnosis, and longitudinal monitoring of senescence-driven pathologies. By integrating organ-specific imaging biomarkers with molecular insights, PET probes are poised to transform our ability to manage and treat age-related diseases through personalized approaches. Full article

Alpha-synuclein (αsyn) misfolding and aggregation underlie several neurodegenerative disorders, including Parkinson’s disease. Early oligomeric intermediates are particularly toxic yet remain challenging to detect and characterize within cellular systems. Here, we employed the luminescent conjugated oligothiophene h-FTAA to investigate early aggregation events of human wildtype (huWT) and A53T-mutated αsyn (huA53T) both in vitro and in HEK293 cells stably expressing native human-αsyn. Comparative fibrillation assays revealed that h-FTAA detected αsyn aggregation with higher sensitivity and earlier onset than Thioflavin T, with the A53T variant displaying accelerated fibrillation. HEK293 cells stably expressing huWT- or huA53T-αsyn were exposed to respective pre-formed fibrils (PFFs), assessed via immunocytochemistry, h-FTAA staining, spectral emission profiling, and fluorescence lifetime imaging microscopy (FLIM). Notably, huA53T PFFs promoted earlier aggregation patterns and yielded narrower fluorescence lifetime distributions compared with huWT PFFs. Spectral imaging showed h-FTAA emission maxima (~550–580 nm) red-shifted and broadened in cells along with variable lifetimes (0.68–0.87 ns), indicating heterogeneous aggregate conformations influenced by cellular milieu. These findings demonstrate that h-FTAA is useful for distinguishing early αsyn conformers in living systems and, together with stable αsyn-expressing HEK293 cells, offers a platform for probing early αsyn morphotypes. Taken together, this opens for further discovery of biomarkers and drugs that can interfere with αsyn aggregation. Full article

Antibody-free nucleic acid lateral flow assays (AF-NALFA) are an established approach for rapid detection of amplified pathogens DNA but can yield inconsistent signals across targets. Since AF-NALFA depends on dual hybridization of probes to single-stranded amplicons (ssDNA), site-specific thermodynamic (Gibbs free energy-ΔG) at probe-binding regions may be crucial for performance. This study investigated how site-specific-ΔG and sequence complementarity at probe-binding regions determine Test-line signal generation, comparing native and synthetic amplicons and assessing the effects of local secondary structures and mismatches. Asymmetric PCR-generated ssDNA amplicons of Listeria monocytogenes, Mycobacterium leprae, and Leishmania amazonensis were analyzed in silico and tested in AF-NALFA prototypes with gold-labeled thiol probes and biotinylated capture probes. T-line signals were photographed, quantified (ImageJ version 1.4k), and statistically correlated with site-specific-ΔG. While native ssDNA from M. leprae and L. amazonensis failed to produce AF-NALFA T-line signals, L. monocytogenes yielded strong detection. Site-specific-ΔG below −10 kcal/mol correlated with reduced hybridization. Synthetic oligos preserved signals despite structural constraints, whereas ~3–4 mismatches, especially at capture probe regions, markedly impaired T-line intensity. The performance of AF-NALFA depends on the synergism between thermodynamic accessibility, site-specific-ΔG-induced site constraints, and sequence complementarity. Because genomic context affects hybridization, target-specific thermodynamic in silico evaluation is necessary for reliable pathogen DNA detection. Full article

Glycosaminoglycans (GAGs) are part of the extracellular matrix (ECM) and play a major role in maintaining their physiological function. During pathological processes, the ECM is remodeled and its GAG composition changes. Hyaluronic acid (HA) is one of the GAGs that plays an important role in pathological processes such as inflammation and cancer and is therefore an interesting target for imaging. To provide iron oxide nanoparticles (IONP) that bind to hyaluronic acid (HA) as specific probes for molecular imaging, a peptide with high affinity for HA was covalently bound to the surface of commercial IONP (synomag^®-D, NH2) leading to hyaluronic acid-specific iron oxide nanoparticles (HAIONPs). Affinity measurements using a quartz crystal microbalance (QCM) showed a very high affinity of HAIONP to HA, but not to the control chondroitin sulfate (CS). HAIONPs exhibit a very high magnetic particle spectroscopy (MPS) signal amplitude, which predestines them as HA-selective tracers for magnetic particle imaging (MPI). The high relaxivity coefficient r₂ also makes HAIONP suitable for magnetic resonance imaging (MRI) applications. HAIONP therefore offers excellent prerequisites for further development as a probe for the specific quantitative imaging of the HA content of the ECM in pathological areas. Full article

A novel, cost-effective, label-free biosensing strategy has been established for real-time quantification of alkaline phosphatase (ALP) activity, integrating the Tyndall effect with smartphone imaging technology. This method utilizes a handheld laser diode to probe the enzyme-triggered in situ assembly of Cu-guanosine monophosphate (Cu-GMP) coordination polymers, which exhibit tunable Tyndall scattering properties. In the absence of ALP, Cu²⁺ ions chelate with GMP to form Cu-GMP coordination polymers, generating an intense Tyndall effect. Conversely, ALP-mediated hydrolysis of GMP disrupts the formation of Cu-GMP coordination polymers, resulting in diminished light scattering. The intensity of the Tyndall effect is directly proportional to the concentration of Cu-GMP coordination polymers, which in turn correlates with ALP activity levels. A comprehensive investigation of experimental parameters was conducted, including pH, incubation temperature, GMP concentration, incubation time, synthesis duration, and CuSO₄ concentration. Under optimized conditions, the developed smartphone-assisted colorimetric assay enables the detection of ALP activity within the range of 0.375–3.75 U/mL, with a limit of detection of 0.184 U/mL. The application of this method to serum samples yielded recovery rates ranging from 102.6% to 109.0%. In summary, this smartphone-based colorimetric platform offers a portable and versatile approach for instrument-free detection of ALP activity, with potential applications in point-of-care diagnostics and resource-limited settings. Full article

Background: Perianal Crohn’s disease (pCD) is one of the most disabling complications of inflammatory bowel disease, characterized by fistulas and abscesses that demand precise imaging for diagnosis, treatment planning, and follow-up. Magnetic resonance imaging (MRI) is considered the reference standard, but endoanal ultrasound (EAUS) with high-frequency 360° probes provide a readily available, cost-effective, and repeatable alternative. Methods: We performed a narrative review of the literature, evaluating studies on the EAUS technique, diagnostic applications, distinguishing features of Crohn’s-related fistulas, and comparative analyses with MRI. Consensus documents and structured reporting initiatives were also included. Results: EAUS provides high-resolution visualization of the anal sphincter complex and intersphincteric space, enabling the reliable detection of fistulas and abscesses. Characteristic features such as tract width > 4 mm, bifurcation, hyperechoic debris, the Crohn’s Ultrasound Fistula Sign (CUFS), and the rosary sign assist in differentiating Crohn’s from cryptoglandular fistulas. EAUS is well-suited for serial monitoring, perioperative seton guidance, and therapeutic decision-making. Emerging tools such as Doppler and shear wave elastography provide additional information on activity and fibrosis. MRI remains indispensable for supralevator disease, deep pelvic sepsis, and standardized activity indices. Comparative studies indicate similar sensitivity for simple fistulas, with MRI superior in complex cases; combining both modalities maximizes accuracy. Conclusions: EAUS is a practical and repeatable imaging tool that complements MRI in the multidisciplinary management of perianal Crohn’s disease. Advances such as 3D imaging, contrast enhancement, and elastography may enable validated activity scoring—for example, a future PEACE (Perianal Endosonographic Activity in Chron’s Evaluation) Index—further strengthening its role in longitudinal care. Full article

Learned systems in the domain of visual recognition and cognition impress in part because even though they are trained with datasets many orders of magnitude smaller than the full population of possible images, they exhibit sufficient generalization to be applicable to new and previously unseen data. Since training data sets typically represent such a small sampling of any domain, the possibility of bias in their composition is very real. But what are the limits of generalization given such bias, and up to what point might it be sufficient for a real problem task? There are many types of bias as will be seen, but we focus only on one, selection bias. In vision, image contents are dependent on the physics of vision and geometry of the imaging process and not only on scene contents. How do biases in these factors—that is, non-uniform sample collection across the spectrum of imaging possibilities—affect learning? We address this in two ways. The first is theoretical in the tradition of the Thought Experiment. The point is to use a simple theoretical tool to probe into the bias of data collection to highlight deficiencies that might then deserve extra attention either in data collection or system development. Those theoretical results are then used to motivate practical tests on a new dataset using several existing top classifiers. We report that, both theoretically and empirically, there are some selection biases rooted in the physics and imaging geometry of vision that challenge current methods of classification. Full article

A series of experiments were carried out to evaluate different anti-/de-icing approaches for a Pitot probe. Using the Iowa State University Icing Research Tunnel (ISU-IRT), this study compared the performance of a traditional electrically heated system with that of a hybrid concept combining reduced-power electrical heating and a superhydrophobic surface (SHS) coating. The effectiveness and energy efficiency of both methods were assessed. High-speed imaging was employed to capture the transient ice accretion and removal phenomena on the probe model under a representative glaze icing condition, while infrared thermography provided surface temperature distributions to characterize the unsteady heat transfer behavior during the protection process. Results indicated that, due to the placement of the internal resistive heating elements, ice deposits on the total pressure tube were easier to shed than those on the supporting structure. Relative to the conventional approach of maintaining a fully heated probe, the hybrid technique achieved comparable anti-/de-icing performance with substantially reduced power requirements—showing up to ~50% savings during anti-icing operation and approximately 30% lower energy use with 24% faster removal during de-icing. These findings suggest that the hybrid strategy is a promising alternative for improving Pitot probe icing protection. Full article

Mid-infrared (MIR) spectroscopy enables non-invasive identification of chemical species by probing absorption spectra associated with molecular vibrational modes, where spectral filters play a central role. Conventional plasmonic metasurfaces have been explored for MIR filtering in reflection and transmission modes but typically suffer from broad spectral profiles and low efficiencies. All-dielectric metasurfaces, although characterized by low intrinsic losses, are largely limited to reflection mode operation. To overcome these limitations, we propose a hybrid metal-dielectric metasurface that combines the advantages of both platforms while simplifying fabrication compared to conventional Fabry–Pérot filters. The proposed filter consists of silicon (Si) crosses atop gold (Au) square patches and demonstrates a transmission efficiency of 87% at the operating wavelength of 4.28 µm, with a full width half maximum (FWHM) as narrow as 43 nm and a quality factor of approximately 99.5 at λ = 4.28 μm. Numerical simulations attribute this performance to hybridization of Mie lattice resonances in both the gold patches and silicon crosses. By providing narrowband, high-transmission filtering in the MIR, the hybrid metasurface offers a compact and versatile platform for selective gas detection and imaging. This work establishes hybrid metal–dielectric metasurfaces as a promising direction for next-generation MIR spectroscopy. Full article

Monkey beetles (Hopliini, Scarabaeoidea) are a species-rich group of flower-visiting insects that are specialized to feed on floral tissue, pollen and/or nectar. We studied ten South African species, examining morphological features associated with their specific feeding preferences. This is the first attempt in a limited number of beetle species to comparatively investigate both the mouthparts and the alimentary tract in relation to ingested food. Using light microscopy, we found cutting edges on the mandibles and galea teeth in flower tissue-feeding species. Pollen feeders have numerous bristles on the maxillae and a prominent mola on the mandibles that are likely used for gathering and grinding pollen. The elongate heads and mouthparts of the nectar feeders are considered an adaptation that enable these species to mop up nectar while probing flowers. Using µCT imaging and reconstructions of the entire alimentary tract, our morphometric results suggest that food preferences are not related to total relative gut length, although the ratio of foregut to body length was greater in pollen- and nectar-feeding monkey beetles than in floral tissue-feeders. The midgut of females tends to be longer relative to body size compared to males. Our work serves as a basis for generating hypotheses for future research that includes gut morphology in flower-visiting insects. Full article

Tele-ultrasound systems enable remote diagnostic imaging by transmitting both motion commands and haptic feedback between a sonographer and a robotic probe. While these systems aim to replicate conventional ultrasound procedures, they rarely address the physical strain typically experienced by sonographers. In this study, the effect of applying a force scaling strategy to haptic feedback on reducing muscular fatigue and task-induced stress during a realistic tele-ultrasound task is studied. First, a thorough operational and biomechanical analysis of the abdominal US procedure was performed to reconstruct a representative task in the laboratory. Then, a bilateral position–force tele-ultrasound architecture was implemented, and a total of 11 subjects performed the reconstructed remote ultrasound task under two randomized conditions: with and without force scaling. Surface electromyography (sEMG) signals were acquired from seven upper-limb muscles (posterior deltoid, trapezius, anterior deltoid, biceps, triceps, wrist flexors, and wrist extensors). Teleoperation-related stress was also assessed using a seven-item Likert-scale self-report questionnaire administered after each trial. Statistical significance was tested using Repeated Measures ANOVA for EMG data and the Wilcoxon signed-rank test for stress scores. The results showed a statistically significant reduction in muscle activation in 5 out of 7 muscles, and a clear mitigation of fatigue progression over time in the scaled condition. Additionally, perceived stress levels were significantly lower in the presence of force scaling in overall stress scores. These findings support the effectiveness of force scaling as a tool to enhance ergonomics in tele-ultrasound procedures without compromising the operator’s ability to perform the task. The proposed methodology proved robust and generalizable, offering valuable insight into the integration of human-centered design in tele-operated diagnostic systems. Full article