Fast Scanning Research Articles

6.7–8.1 µm tunable single-frequency difference frequency generation in ZGP for high-resolution spectroscopy

Difference frequency generation (DFG) based tunable single-frequency mid-infrared (MIR) light sources are desirable for high-resolution spectroscopy, sensing, and imaging. In this work, we demonstrate a continuous-wave (CW) single-frequency DFG in a ZnGeP2 (ZGP) crystal driven by all-fiber near-infrared (NIR) fiber lasers, for the first time to our knowledge. The all-fiber NIR laser sources consist of a 1.5 µm erbium-doped fiber amplifier seeded by a CW tunable fast scanning single-frequency laser and a 1.9 µm CW tunable single-frequency thulium-doped fiber laser. Taking advantage of the high nonlinear coefficient and large birefringence of the ZGP crystal, single-frequency DFG in ZGP achieves a broad spectral tuning range from 6.7 to 8.1 µm, with an output power at the 10 µW level. Precise detection of C2H2 gas by continuously scanning the DFG source across a spectral range of 1.1 THz (∼34 cm−1) is also presented, highlighting the potential of the tunable DFG source for high-resolution optical spectroscopy applications. We anticipate this work will provide what we believe to be a new platform for spectroscopy in the molecular fingerprint spectral region.

Social isolation induces addictive behavior and increases release of dopamine in the <i>nucleus accumbens</i> in response to stimulation of the positive reinforcing zone

The study of the role of social isolation in the pathogenesis of addictive behavior disorders is an important medical and biological problem. Of particular importance are the limitations of social experience in ontogenesis. This work makes an attempt to find a connection between social isolation in ontogenesis and impulsive-compulsive behavior, as an indicator of the premorbid background for gaming and other forms of behavioral addictions. The mechanisms of addictive behavior in rats reared in isolation (IS) were investigated by analyzing the extracellular release of dopamine in response to stimulation of the positive reinforcing zone. Before the experiments, male rats were kept in individual cages from the 21st day of birth to the 90th day. To study elements of addictive behavior, a variant of the Iowa Gambling Task in a 3-arm maze and a method of developing compulsive overeating using intermittent consumption of high-calorie foods were used. To study compulsive behavior, a marble test was used against the background of withdrawal from a high-calorie diet. Surgeries were performed to implant electrodes into the ventral tegmental area (VTA) and the nucleus accumbens in rats exhibiting elements of addictive behavior in the 3-arm maze. These animals were then trained to respond to VTA self-stimulation. Dopamine release was recorded telemetrically in freely moving rats in response to electrical stimulation of the VTA self-stimulation zone. Fast scan cyclic voltammetry was used to determine changes in dopamine levels in the extracellular environment of the nucleus accumbens. IS entered less into the arm with a high degree of probability but with a low reward, and entered more in the arm with a low degree of probability, but with a high reward, which is associated with the appearance of impulsivity in behavior. In the model of compulsive overeating, the number of approaches to the feeder in IS increased, and against the background of withdrawal of high-calorie food, IS were more active in the marble test. In IS exhibiting elements of addictive behavior in the 3-arm maze, the content of extracellular dopamine in response to electrical stimulation of the VTA self-stimulation zones did not reveal any differences compared to the control group of rats with addictive behavior in the maze. At the same time, IS exhibiting elements of addictive behavior in the maze showed a more pronounced dopamine response to a complex stimulus: a conditioned signal used during maze learning light + VTA stimulation. Thus, rearing in the IS causes an increase in dopamine release in the nucleus accumbens in response to stimulation of the positive reinforcement area associated with addictive behaviors: impulsivity and compulsivity. A conclusion is drawn about the prospects of studying the extracellular release of dopamine and assesses addictive behavior disorders caused by limited social contacts in ontogenesis.

Feasibility of using toroidal transceivers for acquiring intraoperative MR images around deep brain stimulation electrodes

IntroductionMagnetic resonance imaging (MRI) provides excellent soft tissue contrast for visualizing of deep brain stimulation (DBS) targets, allowing validation of the electrode placement, and assessing complications such as microhemorrhage and edema. However, the presence of the electrodes can introduce challenges such as radiofrequency (RF) induced current artifacts and excessive heating of the electrode contacts. Additionally, extended procedure times are also considered a disadvantage when using MRI as an intraoperative imaging modality following DBS electrode placement. MethodWe propose a novel approach of using toroidal resonators to inductively couple the shaft of the electrode to the scanner's transmit-receive chain thereby utilizing it as a localized imaging antenna. The small extent of the field generated by the electrode antenna allows fast imaging with smaller field-of-views (FOVs) spanning only a few centimeters. Furthermore, we present a fast and accurate safety monitoring strategy that can be used to predict the temperature increase at the electrical contacts of the electrode. Results and DiscussionImaging with the toroidal transceiver yields a higher signal-to-noise ratio (SNR) efficiency in proximity to the electrodes. This approach reduced the RF induced current artifacts around the electrode which enhanced the visibility of the shaft and improved electrode localization. Moreover, the limited sensitivity around the electrode can be exploited to perform fast scans with small FOVs. The predicted heating around DBS contacts was in quantitative agreement with the experimental heating in swine studies with a normalized root-mean-square error (NRMSE) ≤ 0.09.

Toward the Application of Dual-Energy Computed Tomography with Virtual Non-Hydroxyapatite Color-Coded Maps to Identify Traumatic Fractures in Daily Emergency Settings

To evaluate the advantages of dual-energy computed tomography (DECT) virtual non-hydroxyapatite color mapping (VNHAP) in combination with standard bone CT (BCT) in the identification of subtle or occult traumatic fractures referred to emergency and acceptance departments (DEAs). Forty patients (22 men; mean age 83 ± 23.7 y) with suspected traumatic fractures referred to our emergency department and examined with a fast kilovoltage-switching single-source spectral CT scan between January and October 2023 were retrospectively reviewed. The BCT and VNHAP images were blindly evaluated by two radiologists with >10 years and <2 years of experience in musculoskeletal imaging. Both techniques were evaluated in terms of sensitivity (SE), specificity (SP), positive and negative predictive values (PPVs and NPVs) and accuracy for fracture detection, as confirmed at a 3-month clinical–instrumental follow-up. Inter-observer agreement and examination times were also analyzed. Fractures were confirmed in 18/40 cases. The highest values of diagnostic performance for VNHAP images were obtained in terms of SP (90.9% and 95%) and PPV (87.5% and 92.8%) and for the less experienced operator. No statistically significant differences were observed between the diagnostic accuracy of the two readers in the evaluation of VNHAP images. Inter-observer agreement was moderate (κ = 0.536) for BCT and substantial (κ = 0.680) for VNHAP. Comparing the two operators, a significantly longer examination time for BCT and no significant difference for VNHAP were registered. Our preliminary experience may encourage the employment of VNHAP maps in combination with BCT images in emergency settings. Their use could be time-saving and valuable in terms of diagnostic performance, especially for less experienced operators.

Wideband ratiometric measurement of tonic and phasic dopamine release in the striatum.

Reward learning, cognition, and motivation are supported by changes in neurotransmitter levels across multiple timescales. Current measurement technologies for various neuromodulators (such as dopamine and serotonin) do not bridge timescales of fluctuations, limiting the ability to define the behavioral significance, regulation, and relationship between fast (phasic) and slow (tonic) dynamics. To help resolve longstanding debates about the behavioral significance of dopamine across timescales, we developed a novel quantification strategy, augmenting extensively used carbon-fiber Fast Scan Cyclic Voltammetry (FSCV). We iteratively engineered the FSCV scan sequence to rapidly modify electrode sensitivity within a sampling window and applied ratiometric analysis for wideband dopamine measurement. This allowed us to selectively eliminate artifacts unrelated to electrochemical detection (i.e., baseline drift), overcoming previous limitations that precluded wideband dopamine detection from milliseconds to hours. We extensively characterize this approach in vitro , validate performance in vivo with simultaneous microdialysis, and deploy this technique to measure wideband dopamine changes across striatal regions under pharmacological, optogenetic, and behavioral manipulations. We demonstrate that our approach can extend to additional analytes, including serotonin and pH, providing a robust platform to assess the contributions of multi-timescale neuromodulator fluctuations to cognition, learning, and motivation.

Fast reconstruction 3D computed tomography image of stacked cell under faster scanning by dual-branch cross-fusion flat bottom network

Abstract Cone beam computed tomography (CBCT) fast scanning and reconstruction is a key step to achieve rapid detection of internal defects in batteries. In this work, we have achieved a faster CT scanning just in 5 seconds by reducing the X-ray exposure time in sparse view CT. However, the CT data is extremely incomplete by faster scanning; the existing reconstruction methods are difficult to reconstruct a high quality three-dimensional (3D) CT image of stacked cells. To address this issue, we propose a 3D CT image reconstruction network, which can reconstruct higher quality CT images from low quality 3D volume data. The input data of the reconstruction network is not 2D projection data, but 3D volume data. In this network, a high and low resolution dual-branch cross-fusion flat bottom structure is designed. The high resolution flat bottom branch aims to preserve detailed information, while the low resolution flat bottom branch focuses on capturing more semantic information. Cross-fusion between these branches mitigates the loss of semantic details. Additionally, the auxiliary loss function, the main loss function, and the 3D attention module are designed to enhance semantic accuracy and the learning performance of the network. The 3D training data is collected under a fast scanning strategy spanning 5-60 seconds. During the training phase, we use clipping block technology to cut the 3D volume data, enabling direct training on the 3D volume data. Our experimental results demonstrate that our 3D reconstruction network outperforms mainstream algorithms under this faster scanning strategy, which is able to reconstruct higher quality 3D CT images just in 15 seconds. Ablation experiments confirm the positive impact of the dual-branch cross-fusion flat bottom structure, attention module, and loss functions on improving the quality of 3D CT images.

POSSIBILITIES OF RADIOLOGICAL SCAN METHODS WITH POST-PROCESSING IMAGE RECONSTRUCTION IN THE ASSESSMENT OF ATHEROSCLEROTIC PLAQUES OF THE CAROTID ARTERIES

The aim. To establish the informativeness of the methods of computed tomography angiography, ultrasound diagnostics and magnetic resonance arteriography without contrast in patients with atherosclerosis of carotid arteries. Materials and methods. During July 2022 - July 2024, 82 male patients were examined on the basis of the Neurological Pathology Diagnostic Center of the KNP "Regional Clinical Hospital of the Ivano-Frankivsk Regional Council". Forty-six of them were included in the study group with clinical signs of atherosclerotic lesions of the carotid arteries. Thirty-six patients with asymptomatic course of the carotid arteries atherosclerosis were chosen as the control group. Patients of both groups were aged 51-79 years, and were homogeneous in terms of concomitant diseases, duration of smoking and lipidogram results. Exclusion criteria from both cohorts were: the presence of arrhythmia, radiation treatment of oncological processes in the projection of the head and neck, diagnosed Alzheimer's disease or Fara's disease, lack of written informed consent to participate in the study, impaired legal capacity of the person, when the written consent cannot be considered truly conscious. CTA was performed using a 160-slice computer tomograph Aquilion Prime Toshiba Scanner TSX-302A (Toshiba) with SUREPlaque software to analyze atherosclerotic plaques and vessels in the Carotid CTA fast scanning mode. MRI of the head and neck with non-contrast MR-arteriography was performed using a 1.5 Tesla Phillips Achieva device using blood flow imaging sequences: s3DI MC (three-dimensional time of flight MR-angiography). Ultrasound of the carotid arteries was performed using the Esaote MyLab9eXP device using B-mode, Doppler mapping and elastography. Atherosclerotic plaques were assessed according to the new imaging-based classification - Carotid Plaque-RADS from 2024. The results. According to the classification of Carotid Plaque-RADS, the following results were obtained according to visualization by ultrasound and CT methods: a combination of plaques of categories from Plaque-RADS 2 to Plaque-RADS 4, considering the types of each category, was detected in patients of both groups. There was no significant difference between the groups in the assessment of the structure of the atherosclerotic plaque (p=0.616). For the study group, the detection of the higher percentage of the stenotic lumen of the vessel was statistically different (median - 68.5% (interquartile range 9.75%)) compared to the control group (median - 60.0% (interquartile range 7.5%)) (p =0.048). A comparison of the degree of stenosis by ultrasound and CTA methods was carried out, where a direct correlation of very high strength according to the Chaddock scale was established (r=0.934 (confidence interval: 0.881 – 0.964), p˂0.001). Atherosclerotic lesions were characterized by indirect signs on MRI, namely: wall filling defects, which most likely correspond to plaques, increased bends of main arteries. Conclusions. Ultrasound diagnostics and reconstructive post-processing capabilities of computed tomography were practically equivalent in assessing the degree of stenosis with high correlation strength (r=0.934) and highly informative images of atherosclerotic masses of carotid arteries, while non-contrast magnetic resonance arteriography allowed to suspect atherosclerotic lesions as an area of ​​a filling defect without detailed tissue structures.

Volumetric voltage imaging of neuronal populations in the mouse brain by confocal light-field microscopy.

Voltage imaging measures neuronal activity directly and holds promise for understanding information processing within individual neurons and across populations. However, imaging voltage over large neuronal populations has been challenging owing to the simultaneous requirements of high imaging speed and signal-to-noise ratio, large volume coverage and low photobleaching rate. Here, to overcome this challenge, we developed a confocal light-field microscope that surpassed the traditional limits in speed and noise performance by incorporating a speed-enhanced camera, a fast and robust scanning mechanism, laser-speckle-noise elimination and optimized light efficiency. With this method, we achieved simultaneous recording from more than 300 spiking neurons within an 800-µm-diameter and 180-µm-thick volume in the mouse cortex, for more than 20 min. By integrating the spatial and voltage activity profiles, we have mapped three-dimensional neural coordination patterns in awake mouse brains. Our method is robust for routine application in volumetric voltage imaging.

Measuring very low radiation doses in PTFE for nuclear forensic enrichment reconstruction

Every country that has made nuclear weapons has used uranium enrichment to do so. Despite the centrality of this technology to international security, there is still no reliable physical marker of past enrichment in the open literature that can be used to perform forensic verification of historically produced weapons on gas centrifuges. We show that the extremely low radioactivity from uranium alpha emissions during enrichment leaves detectable and irreversible calorimetric signatures in the common enrichment gasket material PTFE, allowing for historical reconstruction of past enrichment activities at a sensitivity better than one weapon's quantity of highly enriched uranium. Fast scanning calorimetry also enables the measurement of recrystallization enthalpies of sequentially microtomed slices, confirming the magnitude and the type of radiation exposure while also providing detection of tampering and a method for analyzing field samples useful for treaty verification. This work opens the door for common items to be turned into precise dosimeters to detect the past presence of radioactivity, nuclear materials, and related activities with high confidence.

Clinical Outcomes and Diagnostic Utility of Focused Assessment with Sonography for Trauma (FAST) In Trauma Patients: A Retrospective Analysis

Clinical Outcomes and Diagnostic Utility of Focused Assessment with Sonography for Trauma (FAST) In Trauma Patients: A Retrospective Analysis

Complexity of confined water vitrification and its glass transition temperature

The ability of vitrification when crossing the glass transition temperature (Tg) of confined and bulk water is crucial for myriad phenomena in diverse fields, ranging from the cryopreservation of organs and food to the development of cryoenzymatic reactions, frost damage to buildings, and atmospheric water. However, determining water's Tg remains a major challenge. Here, we elucidate the glass transition of water by analyzing the calorimetric behavior of nano-confined water across various pore topologies (diameters: 0.3 to 2.5 nm). Our approach involves subjecting confined water to annealing protocols to identify the temperature and time evolution of nonequilibrium glass kinetics. Furthermore, we complement this calorimetric approach with the dynamics of confined water, as seen by broadband dielectric spectroscopy and linear calorimetric measurements, including the fast scanning technique. This study demonstrated that confined water undergoes a glass transition in the temperature range of 170 to 200 K, depending on the confinement size and the interaction with the confinement walls. Moreover, we also show that the thermal event observed at ~136 K must be interpreted as an annealing prepeak, also referred to as the "shadow glass transition." Calorimetric measurements also allow the detection of a specific heat step above 200 K, which is insensitive to annealing and, thereby, interpreted as a true thermodynamic transition. Finally, by connecting our results to bulk water behavior, we offer a comprehensive understanding of confined water vitrification with potential implications for numerous applications.

Insights into glass surface dynamics from fast scanning calorimetry studies of softening and vaporization of ultrathin molecular films.

Chemical and physical processes on the surfaces of amorphous solids have been the focus of many studies over the past decades. These studies have established that dynamics in a thin layer near a glass surface are often dramatically faster than those in the glass bulk. Nevertheless, recent advances also emphasize the need for new experimental techniques capable of characterizing the structure and dynamics of the near-surface regions in glassy materials at the molecular length scale. Using a quasi-adiabatic fast scanning calorimetry (FSC) technique, we have investigated softening and vaporization of pure amorphous methylbenzene films of moderately heightened kinetic stability with thicknesses ranging from 1 to 20nm. The analysis of the FSC thermograms reveals the existence of a high fictive temperature (liquid-like) layer on the surface of the solid glass with a thickness of 3.5 ± 0.5nm or seven molecular diameters. Furthermore, the width of the boundary between liquid-like and solid layers in the films is less than 1nm. These preliminary findings compliment and substantiate past determinations of the mobile surface layer thicknesses obtained by introduction of nanoparticles or spectroscopic molecular probes to near-surface regions of amorphous samples. The developed FSC methodology will advance the theoretical and computational research by providing calorimetric data on the enhanced interfacial dynamics phenomenon in a variety of low-molecular-weight amorphous materials.

Critical Cooling Rate of Fast-Crystallizing Polyesters: The Example of Poly(alkylene trans-1,4-cyclohexanedicarboxylate)

Controlling the cooling rate experienced by a material during a manufacturing process is a challenge and a major issue. Industrial processing techniques are very diverse and may involve a whole range of cooling rates, which are sometimes extremely high for small and/or thin manufactured parts. For polymers, the cooling rate has consequences on both the microstructure and the time-dependent properties. The common cooling rates associated with conventional calorimetric measurements are generally limited to a few tens of degrees per minute. This work combines several calorimetric techniques (DSC, modulated-temperature DSC, stochastically-modulated DSC and Fast Scanning Calorimetry) to estimate the critical cooling rate required to melt-quench fast-crystallizing polyesters to their fully amorphous state, based on the example of a series of poly(alkylene trans-1,4-cyclohexanedicarboxylate) (PCHs) with a number of methylene groups in the main structure of the repeating unit nCH2 varying from 3 to 6. The even-numbered ones require faster cooling rates (about 3000 K s−1 for nCH2 = 4, between 500 and 1000 K s−1 for nCH2 = 6) compared to the odd-numbered ones (between 50 K min−1 and 100 K s−1 for nCH2 = 3, between 10 and 30 K min−1 for nCH2 = 5).

Advanced electrochemical detection of pyrophosphatase activity in LNCaP cells utilizing in-situ redox of copper

The necessity for precise delineation and quantitation of pyrophosphatase (PPase) activities is underscored, especially in aggressive prostate cancer, driving the demand for more refined analytical techniques due to challenges associated with inadequate sensitivity and poor signal amplification. In response, a novel electrochemical method utilizing in-situ copper(II) (Cu(II))-based Fast Scan Cyclic Voltammetry (FSCV) is introduced for the advanced detection of PPase in LNCaP prostate cancer cells. This technique is characterized by the exploitation of competitive binding between Cu(II) and L-Phenylalanine (L-Phe) versus pyrophosphate (PPi), with FSCV technology enhanced by ohmic drop compensation to improve detection sensitivity and signal reliability. Through the application of the FSCV technique transitioned to Current(I)-Voltage(V) analysis, the signal generation is facilitated by an L-Phe-Cu(II) complex, driven by the redox reaction of in-situ Cu(II), specifically its rapid transition from the Cu(0) state back to the Cu(II) state. When this complex is anchored onto a gold substrate modified with cucurbit[7]uril (CB[7]) through supramolecular host–guest interactions, a significant FSCV signal is elicited. A detection limit of 0.05 mU/mL (S/N = 3) is subsequently achieved when the method is applied to the quantification of PPase concentration. Leveraging the FSCV method, we have effectively analyzed PPase activity in LNCaP cells, offering a fresh perspective on tumor marker analysis and fostering advancements in drug development.

The Influence of Strain and Sex on High Fat Diet-Associated Alterations of Dopamine Neurochemistry in Mice.

Objective: The objective of this study was to determine the influence of sex and strain on striatal and nucleus accumbens dopamine neurochemistry and dopamine-related behavior due to a high-saturated-fat diet (HFD). Methods: Male and female C57B6/J (B6J) and Balb/cJ (Balb/c) mice were randomly assigned to a control-fat diet (CFD) containing 10% kcal fat/g or a mineral-matched HFD containing 60% kcal fat/g for 12 weeks. Results: Intraperitoneal glucose tolerance testing (IPGTT) and elevated plus maze experiments (EPM) confirmed that an HFD produced marked blunting of glucose clearance and increased anxiety-like behavior, respectively, in male and female B6J mice. Electrically evoked dopamine release in the striatum and reuptake in the nucleus accumbens (NAc), as measured by ex vivo fast scan cyclic voltammetry, was reduced for HFD-fed B6J females. Impairment in glucose metabolism explained HFD-induced changes in dopamine neurochemistry for B6J males and, to a lesser extent, Balb/c males. The relative expressions of protein markers associated with the activation of microglia, ionized calcium binding adaptor molecule (Iba1) and cluster of differentiation molecule 11b (CD11b) in the striatum were increased due to an HFD for B6J males but were unchanged or decreased amongst HFD-fed Balb/c mice. Conclusions: Our findings demonstrate that strain and sex influence the insulin- and microglia-dependent mechanisms of alterations to dopamine neurochemistry and associated behavior due to an HFD.

Development and observation of a three-dimensional scanning coaxial Mie lidar for dynamic monitoring of near-surface aerosol plumes

Accurate three-dimensional spatiotemporal distribution information on near-surface aerosols is of great significance for environmental research. In this study, a 3D scanning coaxial Mie lidar (3D-STML) was developed to achieve a fast three-dimensional scanning observation of aerosol diffusion processes in near-surface areas. 3D-STML generates high-spatiotemporal resolution images of aerosol extinction coefficient in real-time and captures the dynamic changes of aerosols in near real-time. By optimizing the design of the light guide mirror and the telescope sub-mirror, the system has a small overlap. Based on this, a highly stable and high-speed mechanical rotation mechanism was developed to enable three-dimensional observations. The integration of a solid-state high-repetition-rate pulsed laser and a coaxial, optical system for the transmitter and receiver ensures rapid tracking of aerosol plumes. To meet the observation requirements of near-surface aerosols, an aerosol inversion algorithm combining the Fernald and Klett methods was designed and developed. For aerosol plume monitoring needs, an aerosol plume-tracking algorithm based on Kalman filtering was developed to track the spatiotemporal evolution of aerosols automatically. Experimental results demonstrated that 3D-STML is capable of detecting aerosols in a range from 15 m to 4 km, with a distance resolution of 1.5 m and a time resolution of 0.083 s. It can effectively track and capture aerosol plumes. It can be used for large-scale, long-term observation of near-surface aerosols and for monitoring the spatiotemporal evolution of aerosol plumes.

Crystallization and melting of Poly(4-hydroxybutyrate) characterized by fast scanning calorimetry

Poly (4-hydroxybutyrate) (P4HB) is a marine biodegradable polyester with promising applications. Unfortunately, the crystallization and melting behavior of P4HB has not been systematically studied, due to the rapid crystallization near room temperature. In particular, the characterization of crystallization and melting of P4HB by fast scanning calorimetry (FSC) has not been reported previously. In this article, the common differential scanning calorimeter (DSC), polarized optical microscopy (POM), atomic force microscopy (AFM) and FSC were performed to investigate the crystallization and melting behavior of P4HB. The results indicated that melt crystallization facilitated the formation of fragmented crystals rather than complete spherulites. Furthermore, the P4HB exhibited a broad crystallization temperature range from −19 °C to 49 °C, and the crystallization and melting of P4HB was notably affected by the temperature, in addition to the heating or cooling rates. The higher crystallization temperature and lower cooling rates facilitated the formation of well-developed crystals. Remarkably, the P4HB is found to be unable to crystallize at heating or cooling rates exceeding 6 K/s. Moreover, double melting peaks could be discerned at moderate isothermal crystallization temperature exhibiting faster crystallization rate. The findings will provide theoretical guidance on how to optimize the processing parameters in modulating the crystallization of P4HB.

Design of an FPGA-Based Controller for Fast Scanning Probe Microscopy.

Atomic-scale imaging using scanning probe microscopy is a pivotal method for investigating the morphology and physico-chemical properties of nanostructured surfaces. Time resolution represents a significant limitation of this technique, as typical image acquisition times are on the order of several seconds or even a few minutes, while dynamic processes-such as surface restructuring or particle sintering, to be observed upon external stimuli such as changes in gas atmosphere or electrochemical potential-often occur within timescales shorter than a second. In this article, we present a fully redesigned field programmable gate array (FPGA)-based instrument that can be integrated into most commercially available standard scanning probe microscopes. This instrument not only significantly accelerates the acquisition of atomic-scale images by orders of magnitude but also enables the tracking of moving features such as adatoms, vacancies, or clusters across the surface ("atom tracking") due to the parallel execution of sophisticated control and acquisition algorithms and the fast exchange of data with an external processor. Each of these measurement modes requires a complex series of operations within the FPGA that are explained in detail.

On the temporal transfer function in STEM imaging from finite detector response time

Faster scanning in scanning transmission electron microscopy has long been desired for the ability to better control dose, minimise effects of environmental distortions, and to capture the dynamics of in-situ experiments. Advances in scan controllers and scan deflection systems have enabled scanning with pixel dwell times on the order of tens of nanoseconds. At these speeds, the finite response time of the electron detector must be considered as the signal from one electron detection event can contribute to multiple pixels, blurring the features within the image. Here we introduce a temporal transfer function (TTF) to describe and model the effects of detector response time on imaging, as well as a framework for incorporating these effects into simulation.

The Impact of a Student-Taught Point-of-Care Ultrasound Workshop on Confidence in Medical and Pre-Medical Students

Background: The vast utilization of Point-of-Care Ultrasound (POCUS) across medical specialties has increased the need for enhanced undergraduate medical education in image acquisition and interpretation among medical students. However, challenges such as the need for a standardized medical school curriculum and limited trained faculty preceptors restrict its implementation. The literature highlights the potential of student-taught POCUS workshops in expanding access and enhancing learning. This study seeks to evaluate the efficacy of a student-run POCUS workshop for medical and pre-medical students. Methods: A prospective, cross-sectional study assessed the efficacy of first and second-year medical students teaching a POCUS workshop on the Focused Assessment with Sonography for Trauma (FAST) exam. Student workshop participants were asked to complete pre- and post-workshop surveys to assess their confidence in utilizing POCUS and identifying relevant organs and landmarks. Surveys employed a standardized five-point Likert Scale. Results: Of the 43 initial participants, 29 completed both surveys. Results showed a significant increase in self-reported ultrasound experience (1.7 to 3.2, p < 0.001) and confidence in performing the FAST exam and organ identification (2.2-fold increase, p < 0.001). Both medical and pre-medical student cohorts exhibited similar confidence improvements in confidence. Conclusion: This study supports the literature that student-taught POCUS programs may be a viable adjunct to an institution's ultrasound curriculum. Implementing medical student-led workshops could help address current training gaps, enhance students' teaching and leadership skills, and improve confidence in utilizing and interpreting ultrasound images.