X-ray Imaging Studies Research Articles

Exploring the Potential of a Novel Iodine-Based Material as an Alternative Contrast Agent in X-ray Imaging Studies.

Contrast-enhanced mammography is one of the new emerging imaging techniques used for detecting breast tissue lesions. Optimization of imaging protocols and reconstruction techniques for this modality, however, requires the involvement of physical phantoms. Their development is related to the use of radiocontrast agents. This study assesses the X-ray properties of a novel contrast material in clinical settings. This material is intended for experimental use with physical phantoms, offering an alternative to commonly available radiocontrast agents. The water-soluble sodium salt of the newly synthesized diiodine-substituted natural eudesmic acid, Sodium 2,6-DiIodo-3,4,5-TriMethoxyBenzoate [NaDITMB], has been investigated with respect to one of the most commonly applied radiocontrast medium in medical practice-Omnipaque®. For this purpose, simulation and experimental studies were carried out with a computational phantom and a physical counterpart, respectively. Synthetic and experimental X-ray images were subsequently produced under varying beam kilovoltage peaks (kVps), and the proposed contrast material was evaluated. Simulation results revealed equivalent absorptions between the two simulated radiocontrast agents. Experimental findings supported these simulations, showing a maximum deviation of 3.7% between the image gray values of contrast materials for NaDITMB and Omnipaque solutions for a 46 kVp X-ray beam. Higher kVp X-ray beams show even smaller deviations in the mean grey values of the imaged contrast agents, with the NaDITMB solution demonstrating less than a 2% deviation compared to Omnipaque. The proposed contrast agent is a suitable candidate for use in experimental work related to contrast-enhanced imaging by utilizing phantoms. It boasts the advantages of easy synthesis and is recognized for its safety, ensuring a secure environment for both the experimenter and the environment.

Insights into the hydrogen evolution reaction in vanadium redox flow batteries: A synchrotron radiation based X-ray imaging study

The parasitic hydrogen evolution reaction (HER) in the negative half-cell of vanadium redox flow batteries (VRFBs) causes severe efficiency losses. Thus, a deeper understanding of this process and the accompanying bubble formation is crucial. This benchmarking study locally analyzes the bubble distribution in thick, porous electrodes for the first time using deep learning-based image segmentation of synchrotron X-ray micro-tomograms. Each large three-dimensional data set was processed precisely in less than one minute while minimizing human errors and pointing out areas of increased HER activity in VRFBs. The study systematically varies the electrode potential and material, concluding that more negative electrode potentials of −200 mV vs. reversible hydrogen electrode (RHE) and lower cause more substantial bubble formation, resulting in bubble fractions of around 15%–20% in carbon felt electrodes. Contrarily, the bubble fractions stay only around 2% in an electrode combining carbon felt and carbon paper. The detected areas with high HER activity, such as the border subregion with more than 30% bubble fraction in carbon felt electrodes, the cutting edges, and preferential spots in the electrode bulk, are potential-independent and suggest that larger electrodes with a higher bulk-to-border ratio might reduce HER-related performance losses. The described combination of electrochemical measurements, local X-ray micro-tomography, AI-based segmentation, and 3D morphometric analysis is a powerful and novel approach for local bubble analysis in three-dimensional porous electrodes, providing an essential toolkit for a broad community working on bubble-generating electrochemical systems.

Designing, Creating, and Assessing a Modified Pulsincap Delivery System for Intestine Targeting of Fluvastatin in Accordance with Circadian Rhythm

The current study’s objective remains to create the Pulscap delivery system using an insoluble capsule core that contains fluvastatin sodium microspheres. Eudragit RL 100 polymer fluvastatin sodium microspheres were made using the solvent evaporation method. To reduce the possibility of stomach upset, these microspheres were hand-filled into capsules, plugged with hydrogel plugs, then sealed with ethyl cellulose acetate and dipped in an eight: two (vol/vol) Acetone: ethanol solution by butyl pthalate of (0.75%) and 5% cellulose acetate phthalate solution. Formulated dosage form was assessed for in-vivo X-ray imaging studies, in-vitro drug release studies, and in-vivo imaging studies, pharmacokinetic study of the optimized formulation was conducted in a two-way cross-over design with 6 rabbits in each group and the pharmacokinetic parameters (Cmax, Ka, Ke, MRT and AUC0-α) are measured. A Pharmacodynamics study was also performed on lipid profiles in six groups of rabbits. Optimized formulation (F20) which is prepared with a drug and polymer ratio of 1:3, is selected based on a dissolution study which shows a percentage release of 99.98. ± 0.12% at 17th hour. In the in-vivo study, the plasma concentration at 12th hour 53.8 ± 0.02% and at 32nd hour 13.9 ± 0.05%. Pharmacokinetic parameter Cmax (ng/mL): 53.8 ± 0.41, MRT (h): 20.0 ± 0.14, t1/2 (h): 8.52 ± 0.014, Kel (h-1) :0.08 ± 0.014, Ka (h-1):0.25 ± 0.02, AUC0-a (ng h/mL): 944.9. ± 4.05. Serum lipid profile in high cholesterol rabbit after treatment with F20 formulation total cholesterol:240.83 ± 19.76, HDL-C:37.33 ± 2.16, triglycerides:318.67 ± 7.74, VLDL-C:63.73 ± 1.55, LDL-C:139.77 ± 18.74. Compared to lovastatin SR release, lovastatin pulsatile release, and fluvastatin SR release, the results imply that the F20 formulation’s pulsatile drug delivery has established good drug delivery for medications entering the gastrointestinal tract, and it displays superior pharmacokinetic and pharmacodynamic parameters.

Establishment of an image evaluation grading criteria for experimental stifle joint osteoarthritis in dogs: an X-ray and CT imaging study

BackgroundThis study aimed to establish an image evaluation grading criteria for experimental stifle joint osteoarthritis (OA) in anterior cruciate ligament transection induced OA beagle dog models. The severity of OA was assessed using X-ray and computed tomography (CT) imaging.ResultsA total of 32 dogs (8 controls and 24 OA-induced dogs) were included in the study. The OA-induced group showed significantly higher manual joint palpation, gait analysis, and OA severity scores than the control group. Based on these two results, we calculated correlation coefficients. There was a strong positive correlation between manual joint palpation scores and OA severity on diagnostic imaging and between gait analysis scores and OA severity.ConclusionsThe developed grading criteria based on radiographic evaluation correlated with clinical assessments. The study also employed CT imaging to enhance the accuracy and sensitivity of early-stage OA change detection in the stifle joint. However, further studies with larger sample sizes and multiple evaluators are recommended for the validation and generalizability of this grading system. These established image evaluation grading criteria can help evaluate and monitor the efficacy of interventions and changes in OA lesions in canine models.

Noncontact Respiratory Motion Detection in Anesthetized Rodents.

Small animal physiology studies are often complicated, but the level of complexity is greatly increased when performing live-animal X-ray imaging studies at synchrotron radiation facilities. This is because these facilities are typically not designed specifically for biomedical research, and the animals and image detectors are located away from the researchers in a radiation enclosure. In respiratory X-ray imaging studies one challenge is the detection of respiration in free-breathing anaesthetised rodents, to enable images to be acquired at specific phases of the breath and for detecting changes in respiratory rate. We have previously used a Philtec RC60 sensor interfaced to a PowerLab data acquisition system and custom-designed timing hub to perform this task. Here we evaluated the Panasonic HL-G108 for respiratory sensing. The performance of the two sensors for accurate and reliable breath detection was directly compared using a single anesthetized rat. We also assessed how an infrared heat lamp used to maintain body temperature affected sensor performance. Based on positive results from these comparisons, the HL-G108 sensor was then used for respiratory motion detection in tracheal X-ray imaging studies of 21 rats at the SPring-8 Synchrotron, including its use for gated image acquisition. The results of that test were compared to a similar imaging study that used the RC60 for respiratory detection in 19 rats. Finally, the HL-G108 sensor was tested on 5 mice to determine its effectiveness on smaller species. The results showed that the HL-G108 is much more robust and easier to configure than the RC60 sensor and produces an analog signal that is amenable to stable peak detection. Furthermore, gated image acquisition produced sequences with substantially reduced motion artefacts, enabling the additional benefit of reduced radiation dose through the application of shuttering. Finally, the mouse experiments showed that the HL-G108 is equally capable of detecting respiration in this smaller species.

Chitosan-carboxymethyl tamarind gum in situ polyelectrolyte complex-based floating capsules of ofloxacin: In vitro-in vivo studies

The current research attempted to design and evaluate sustained stomach-specific ofloxacin delivery by single-unit hydrodynamically balanced system (HBS)-based floating capsules. These HBS-based floating capsules of ofloxacin were prepared using two oppositely ionic polymers, namely cationic-natured low molecular mass chitosan (LMMCH) and anionic-natured carboxymethyl tamarind gum (CMTG). FTIR results indicated the in situ formation of a polyelectrolyte complex in-between two oppositely charged polymers (i.e., in-between –NH2 group of the cationic natured LMMCH and –COOH groups of the anionic natured CMTG) and the nonexistence of any drug-polymer interaction(s) within these formulated ofloxacin HBS capsules. All these LMMCH-CMTG ofloxacin HBS capsules exhibited drug content uniformity, a sustained in vitro drug-releasing profile over 10 h. The ofloxacin HBS capsules (formulated with 75 mg LMMCH and 25 mg CMTG), which was selected as best formulation (for further studies), exhibited excellent in vitro floatation behaviour in SGF (pH 1.2) over 6 h without any floating lag-time, whereas the same formulation containing barium sulfate (100 mg) instead of drug demonstrated prolonged stomach-specific gastroretention in an in vivo X-ray imaging study using rabbits. Therefore, these types of HBS floating capsules can be useful for stomach-specific gastroretentive floating delivery of other drugs.

Adapted arithmetic optimization algorithm for multi-level thresholding image segmentation: a case study of chest x-ray images

Adapted arithmetic optimization algorithm for multi-level thresholding image segmentation: a case study of chest x-ray images

Eu2O3 doped silicoborate glasses for scintillation material application: Luminescence ability and X-ray imaging

The glass samples were prepared by melt quenching method and changing Eu2O3 concentrations following component of xEu2O3 - 40Na2O - 7.5Gd2O3 - 5SiO2 - (47.5-x)B2O3 (x = 0, 1, 2, 3 mol %). Density and molar volume tend to increase with increasing Eu2O3 concentrations, corresponding to the larger non-bridging oxygen. Fourier transform infrared spectra (FTIR) results point out that the majority BO3 borate group. The absorption spectra were represented in the length of UV-Vis and NIR region. The phonon energy of 3Eu:7.5Gd was 1280.54 cm−1, related to the borate glass host. The photoluminescence and X-ray-induced luminescence spectra of 3Eu:7.5Gd glass showed similar highest intensity at 613 nm (5D0→7F2). The photoluminescence quantum yield (PLQY) of 3Eu:7.5Gd glass shows the highest value at 85.70 %. The scintillation efficiency of 3Eu:7.5Gd glass was 17.51 % of bismuth germanate (BGO) crystal. The decay time owing to Eu3+ emission is 2.054 ms for 2Eu:7.5Gd glass. The highest energy transfer efficiency was 2 mol % of Eu2O3 concentrations (ηET = 70 %). The CIE chromaticity coordinates of the glasses are placed in the reddish-orange area (0.65, 0.35). The spatial resolution of X-ray imaging study was 10 lp/mm. These results suggest that 3 mol % of Eu2O3 doped silicoborate glass is capable of being a scintillator applied in the X-ray imaging system.

Analysis of performance stability under conditions of high & low humidity of polymer electrolyte fuel cells with interdigitated gas flow channels formed on a gas diffusion layer: An X-ray imaging and modeling study

Recently, a new concept was developed for the design of polymer electrolyte fuel cells, based on a flat, solid separator and a porous GDL with interdigitated gas-flow channels. This newly designed cell has demonstrated the ability to overcome the principal issues of the conventional design, in which the interdigitated flow channels are formed on the separator; the latter can experience low performance under high and low humidity conditions. In the present study, we have sought to reveal the mechanism of the performance stability improvement. The temperature and gas flow distributions are calculated by numerical simulation, and the water distribution is visualized by X-ray imaging. From these results, the porous ribs in the newly designed cell are found to play several important roles as follows: under conditions of excess water, the porous ribs help to alleviate water accumulation in the GDL by acting as a reservoir for excess water and also by increasing the temperature in the GDL; and, under conditions of water shortage, the porous ribs alleviate the dry-out of the GDL by withdrawing water from the reservoir and also by decreasing the rate of gas flow forced through the GDL.

In situ synchrotron x-ray imaging and diffraction study of additively manufactured AlSi10Mg alloy under uniaxial tension

In situ synchrotron x-ray imaging and diffraction are used to investigate deformation dynamics in two kinds of additively manufactured AlSi10Mg with different pore configurations. The pre-existing pore configurations are characterized with synchrotron x-ray computed tomography. The specimens are subjected to tensile loading along the build direction and the longitudinal direction. Bulk stress–strain curves (macroscale), strain fields (mesoscale) and x-ray diffraction patterns (microscale) are obtained simultaneously. Scanning electron microscopy characterization is performed as a complement. For the small-pored AlSi10Mg, preferred orientations of pores lead to anisotropic ductility, and only ductile dimples are observed. For the large-pored AlSi10Mg, ductility loss is significant due to its higher porosity, and no remarkable anisotropy is found; both ductile and brittle fracture features are identified. For both types of AlSi10Mg, strain localization occurs around the pores. At the lattice scale, the Al matrix deforms plastically but the Si phase is still strained elastically, and thus, significant stress concentration occurs in the Si phase for the small-pored AlSi10Mg, while stress is more evenly partitioned between the Al matrix and the Si phase for the large-pored AlSi10Mg.

Pediatric Myocarditis.

Myocarditis is a condition caused by acute or chronic inflammation of the cardiac myocytes, resulting in associated myocardial edema and myocardial injury or necrosis. The exact incidence is unknown, but is likely underestimated, with more mild cases going unreported. Diagnosis and appropriate management are paramount in pediatric myocarditis, as it remains a recognized cause of sudden cardiac death in children and athletes. Myocarditis in children is most often caused by a viral or infectious etiology. In addition, there are now two highly recognized etiologies related toCoronavirus disease of 2019 (COVID-19) infection and the COVID-19 mRNA vaccine. The clinic presentation of children with myocarditis can range from asymptomatic to critically ill. Related to severe acute respiratory syndrome-Coronavirus 2 (SARs-CoV-2), children are at greater risk of developing myocarditis secondary to COVID-19 compared to the mRNA COVID-19 vaccine. Diagnosis of myocarditis typically includes laboratory testing, electrocardiography (ECG), chest X-ray, and additional non-invasive imaging studies with echocardiogram typically being the first-line imaging modality. While the reference standard for diagnosing myocarditis was previously endomyocardial biopsy, with the new revised Lake Louise Criteria, cardiac magnetic resonance (CMR) has emerged as an integral non-invasive imaging tool to assist in the diagnosis. CMR remains critical, as it allows for assessment of ventricular function and tissue characterization, with newer techniques, such as myocardial strain, to help guide management both acutely and long term.

Noncontact Respiratory Motion Detection in Anesthetized Rodents

Small animal physiology studies are often complicated, but the level of complexity is greatly increased when performinglive-animal X-ray imaging studies at synchrotron radiation facilities. This is because these facilities are typically not designedspecifically for biomedical research, and the animals and image detectors are located away from the researchers in a radiationenclosure. In respiratory X-ray imaging studies one challenge is the detection of respiration in free-breathing anaesthetisedrodents, to enable images to be acquired at specific phases of the breath and for detecting changes in respiratory rate. Wehave previously used a Philtec RC60 sensor interfaced to a PowerLab data acquisition system and custom-designed timinghub to perform this task. Here we evaluated the Panasonic HL-G108 for respiratory sensing. The performance of the twosensors for accurate and reliable breath detection was directly compared using a single anesthetized rat. We also assessedhow an infrared heat lamp used to maintain body temperature affected sensor performance. Based on positive results fromthese comparisons, the HL-G108 sensor was then used for respiratory motion detection in tracheal X-ray imaging studies of21 rats at the SPring-8 Synchrotron, including its use for gated image acquisition. The results of that test were compared toa similar imaging study that used the RC60 for respiratory detection in 19 rats. Finally, the HL-G108 sensor was tested on 5mice to determine its effectiveness on smaller species. The results showed that the HL-G108 is much more robust and easierto configure than the RC60 sensor and produces an analog signal that is amenable to stable peak detection. Furthermore,gated image acquisition produced sequences with substantially reduced motion artefacts, enabling the additional benefit ofreduced radiation dose through the application of shuttering. Finally, the mouse experiments showed that the HL-G108 isequally capable of detecting respiration in this smaller species.

Noncontact Respiratory Motion Detection in Anesthetized Rodents

Small animal physiology studies are often complicated, but the level of complexity is greatly increased when performinglive-animal X-ray imaging studies at synchrotron radiation facilities. This is because these facilities are typically not designedspecifically for biomedical research, and the animals and image detectors are located away from the researchers in a radiationenclosure. In respiratory X-ray imaging studies one challenge is the detection of respiration in free-breathing anaesthetisedrodents, to enable images to be acquired at specific phases of the breath and for detecting changes in respiratory rate. Wehave previously used a Philtec RC60 sensor interfaced to a PowerLab data acquisition system and custom-designed timinghub to perform this task. Here we evaluated the Panasonic HL-G108 for respiratory sensing. The performance of the twosensors for accurate and reliable breath detection was directly compared using a single anesthetized rat. We also assessedhow an infrared heat lamp used to maintain body temperature affected sensor performance. Based on positive results fromthese comparisons, the HL-G108 sensor was then used for respiratory motion detection in tracheal X-ray imaging studies of21 rats at the SPring-8 Synchrotron, including its use for gated image acquisition. The results of that test were compared toa similar imaging study that used the RC60 for respiratory detection in 19 rats. Finally, the HL-G108 sensor was tested on 5mice to determine its effectiveness on smaller species. The results showed that the HL-G108 is much more robust and easierto configure than the RC60 sensor and produces an analog signal that is amenable to stable peak detection. Furthermore,gated image acquisition produced sequences with substantially reduced motion artefacts, enabling the additional benefit ofreduced radiation dose through the application of shuttering. Finally, the mouse experiments showed that the HL-G108 isequally capable of detecting respiration in this smaller species.

Detecting Tuberculosis from Vietnamese X-Ray Imaging Using Transfer Learning Approach

Deep learning created a sharp rise in the development of autonomous image recognition systems, especially in the case of the medical field. Among lung problems, tuberculosis, caused by a bacterium called Mycobacterium tuberculosis, is a dangerous disease because of its infection and damage. When an infected person coughs or sneezes, tiny droplets can bring pathogens to others through inhaling. Tuberculosis mainly damages the lungs, but it also affects any part of the body. Moreover, during the period of the COVID-19 (coronavirus disease 2019) pandemic, the access to tuberculosis diagnosis and treatment has become more difficult, so early and simple detection of tuberculosis has been more and more important. In our study, we focused on tuberculosis diagnosis by using the chest X-ray image, the essential input for the radiologist’s profession, and researched the effectiveness of the transfer learning approach in the case study of Vietnamese chest X-ray images. We proposed four strategies to clarify our hypothesis in different ways of applying transfer learning and different training set types. We also prepared a Vietnamese X-ray image dataset with the support of the VRPACS team to provide the basis for training and testing deep learning models. Our experiments were carried out by applying three different architectures, Alexnet, Resnet, and Densenet, on international, Vietnamese, and combined X-ray image datasets. After training, all models were verified on a pure Vietnamese X-rays set. The results show that transfer learning is suitable in the case study of Vietnamese chest X-ray images with high evaluating metrics in terms of AUC (Area under the Receiver Operating Characteristic Curve), sensitivity, specificity, and accuracy. In the best strategy, most of the scores were more than 0.93, and all AUCs were more than 0.98.

Predictability of degenerative disc disease by lumbar sagittal alignment on conventional radiograph in comparison with cross-sectional magnetic resonance imaging

Background: Degenerative disc disease (DDD) affects approximately 80% of the population. Changes in the magnitude of lumbar lordosis significantly change the weight-bearing patterns in lumbar facet joints and intervertebral discs. It is essential to understand the contribution of hypo and hyperlordosis toward the development of disc degeneration disease. Materials and Methods: A retrospective study of X-ray and magnetic resonance imaging (MRI) of the lumbosacral spine of 200 patients with chronic low back ache. The lumbar lordotic angle was measured in a standing lateral radiograph using Cobb's method (between the lines drawn along the inferior end plate of D12 and the superior end plate of S1 vertebrae). DDD was assessed on MRI based on the Pfirrmann grading system. The correlation between the lordosis measured on the radiograph and DDD on MRI was assessed. Results: We analyzed the lumbar sagittal alignment effect on the degree of disc degenerative disease. Out of 200 patients, 70 had no disc degenerative disease (Grade I, II) whose Cobb's angle was 45°–75°. The remaining 130 patients showed disc changes (Grades III-V) on MRI and had Cobb's angle <45° or >75°. There was a statistically significant difference between Cobb's angle in normal and DDD patients with P = 0.009 (P < 0.05). Conclusion: DDD correlated with deviation from an optimal lumbar lordotic angle (Cobb's angle) of 45° to 75°. Deviation from optimal values would compromise the optimal weight-bearing conditions on the lumbar spine resulting in DDD. These results may well have implications for the diagnosis, prevention, treatment, and rehabilitation of DDD.

Mitigating keyhole pore formation by nanoparticles during laser powder bed fusion additive manufacturing

Keyhole pore formation is one of the most detrimental subsurface defects in the laser metal additive manufacturing process. However, effective ways to mitigate keyhole pore formation beyond tuning laser processing conditions during keyhole mode laser melting are still lacking. Here we report a novel approach to mitigate keyhole pore formation during laser powder bed fusion (LPBF) process by using stable nanoparticles. The critical keyhole depth for keyhole pore generation (i.e., the largest keyhole depth without keyhole pore formation) during LPBF of Al6061 increases from 246 µm to 454 µm (85% increase) after adding TiC nanoparticles. In-depth x-ray imaging studies and thermo-fluid dynamics simulation enable us to identify that two mechanisms work together to mitigate keyhole pore generation: (1) adding nanoparticles prevents the keyhole from collapsing by increasing the liquid viscosity to impede the protrusion development; (2) adding nanoparticles slows down the keyhole pore movement by increasing the liquid viscosity, resulting in the recapturing of the pore by the keyhole. We further demonstrate that adding TiC nanoparticles can also eliminate the keyhole fluctuation induced keyhole pore during LPBF of Al6061. Our research provides a potential way to mitigate keyhole pore formation for defect lean metal additive manufacturing.

Nanoparticle-enabled increase of energy efficiency during laser metal additive manufacturing

The low energy efficiency of the laser metal additive manufacturing (AM) process is a potential sustainability concern for large-scale industrial production. Explicit investigation of the energy efficiency for laser melting requires the direct characterization of melt pool dimension and vapor depression, which is very difficult due to the opaque nature of the molten metal. Here we report the direct observation and quantification of effects of the TiC nanoparticles on the vapor depression and melt pool formation during laser powder bed fusion (LPBF) of Al6061 by in-situ high-speed high-energy x-ray imaging. Based on the quantification results, we calculated the laser melting energy efficiency (defined here as the ratio of the energy needed to melt the material to the energy delivered by the laser beam) with and without TiC nanoparticles during LPBF of Al6061. The results show that adding TiC nanoparticles into Al6061 leads to a significant increase of laser melting energy efficiency (114% increase on average, 521% increase under 312 W laser power, 0.4 m/s scan speed). Systematic property measurement, simulation, and x-ray imaging studies enable us, for the first time, to identify that three mechanisms work together to enhance the laser melting energy efficiency: (1) adding TiC nanoparticles increases the absorptivity; (2) adding TiC nanoparticles decreases the thermal conductivity, and (3) adding TiC nanoparticles enables the initiation of vapor depression and multiple reflection at lower laser power (i.e., lowers the laser power threshold for keyholing). The method and mechanisms of using TiC nanoparticles to increase the laser melting energy efficiency during LPBF of Al6061 we reported here may guide the development of feedstock materials for more energy efficient laser metal AM. • Quantified nanoparticle-enabled energy efficiency improvement. • Achieved significant increase of energy efficiency by nanoparticles. • Identified mechanisms of nanoparticle-enabled energy efficiency improvement. • Revealed effects of nanoparticles on vapor depression and melt pool evolution.

Comparative analysis of some selected generative adversarial network models for image augmentation: a case study of COVID-19 x-ray and CT images

One of the fastest-growing fields in today’s world is data analytics. Data analytics paved the way for a significant number of research and development in various fields including medicine and vaccine development, DNA analysis, artificial intelligence and many more. Data plays a very important role in providing the required results and helps in making critical decisions and predictions. However, ethical and legislative restrictions sometimes make it difficult for scientists to acquire data. For example, during the COVID-19 pandemic, data was very limited due to privacy and regulatory issues. To address data unavailability, data scientists usually leverage machine learning algorithms such as Generative Adversarial Networks (GAN) to augment data from existing samples. Today, there are over 450 algorithms that are designed to re-generate or augment data in case of unavailability of the data. With many algorithms in the market, it is practically impossible to predict which algorithm best fits the problem in question, unless many algorithms are tested. In this study, we select the most common types of GAN algorithms available for image augmentation to generate samples capable of representing a whole data distribution. To test the selected models, we used two unique datasets, namely COVID-19 CT images and COVID-19 X-Ray images. Five different GAN algorithms, namely CGAN, DCGAN, f-GAN, WGAN, and CycleGAN, were selected and applied to the samples to see how each algorithm reacts to the samples. To evaluate their performances, Visual Turing Test (VTT) and Fréchet Inception Distance (FID) were used. The VTT result shows that a human expert can accurately distinguish between different samples that were produced. Hence, CycleGAN scored 80% in CT image dataset and 77% in X-Ray image dataset. In contrast, the FID result revealed that CycleGAN had a high convergence and therefore generated high quality and clearer images on both datasets compared to CGAN, DCGAN, f-GAN, and WGAN. This study concluded that the CycleGAN model is the best when it comes to image augmentation due to its friendliness and high convergence.

Damage-Free Femtosecond X-Ray Laser Snapshot Imaging of Catalyst Layer Nano-Structures of Polymer Electrolyte Fuel Cells

The realization of the hydrogen society, where hydrogen is used as clean and renewable energy, is desired to reduce carbon dioxide emissions and achieve sustainable development. The polymer electrolyte fuel cell (PEFC) is a key technology for automobiles in the hydrogen society as an alternative to conventional internal combustion engines. However, further improvements in PEFC performances are required for the full-scale spread of fuel cell vehicles. This study aims to image the nanostructures of the catalyst layer, which is particularly important in determining the performance of PEFCs, and correlate the observed structures with mass transfer in the catalyst layer. The catalyst layer contains catalyst-loaded carbon supports thinly covered with an ionomer responsible for proton conduction. We are especially interested in observing the support structure and ionomer coverage.We performed coherent X-ray imaging studies on the catalyst particles of PEFCs using an X-ray free-electron laser (XFEL) facility: SACLA (SPring-8 Angstrom Compact free electron LAser). Femtosecond XFEL allows us to capture radiation-damage-free snapshot images by outrunning major radiation damage processes. Damage-free imaging is of great value because radiation damage often causes a problem in high-resolution electron microscopy observation of ionomers. We used the coherent diffractive imaging (CDI) technique to observe catalyst particles of PEFCs. In CDI, sample images are reconstructed from measured coherent diffraction patterns using phase-retrieval calculation instead of objective lenses. CDI enables quantitative phase imaging and allows high-contrast imaging of the catalyst particles, which are almost transparent to X-rays.The measurement was carried out for catalyst particles in the dried condition and in solution. Our study showed that the image contrast can be adjusted by changing the electron density of the volume surrounding the sample1). The dried sample was prepared by dropping catalyst ink onto a silicon nitride membrane and air-dried. The solution sample was enclosed in micro-liquid enclosure arrays2,3) developed at Hokkaido University. The coherent diffraction patterns were measured by irradiating the sample catalyst particles with the 100-nm-focused XFEL beam with a photon energy of 4 keV using MAXIC-S (Multiple Application X-ray Imaging Chamber-S)4). The phase-retrieval calculation reconstructed the sample images. Fig. 1 shows a reconstructed image of a catalyst particle in water. The reconstructed image shows many white spots, which can be interpreted as platinum-cobalt catalysts. The pixel size of the reconstructed image is 1.3 nm, demonstrating among the highest spatial resolution in X-ray imaging. We will continue our study to observe the support structures and their ionomer coverage to understand the mass transfer in the catalyst layer.This work was supported by the FC-Platform of NEDO (New Energy and Industrial Technology Development Organization). The XFEL experiments were performed at SACLA with the approval of the Japan Synchrotron Radiation Research Institute (JASRI) (Proposal Nos. 2020A8106, 2021A8010, and 2021B8019).

Design and Development of Gastro-retentive Drug Delivery System for Trazodone Hydrochloride: a Promising Alternative to Innovator's Controlled-Release Tablet.

Trazodone hydrochloride (TZN) is a serotonin reuptake inhibitor that treats a major depressive disorder. It exhibits a short plasma half-life of 4.1 h and shows pH-dependent solubility. Above its pKa (6.74), solubility of TZN is very low, affecting its dissolution in the lower part of GIT. Hence, the present work aimed to develop gastro-retentive floating tablet of TZN. Central composite design was employed to optimize the formulation. Formulation variables like the concentration of HPMC-K100M, Polyox WSR 303 Leo, and sodium bicarbonate were evaluated for the responses like floating lag time and drug release. X-ray imaging study was performed on rabbits to determine the in vivo gastric retention of the optimized formulation. The accelerated stability study was conducted on optimized tablets as per ICH guidelines. Floating lag time and f2 value of the optimized formulation were found to be 2.51±0.02 min and 62.79, respectively. X-ray imaging studies in rabbits determined the in vivo gastro retention time. After 12 h of administration, tablet remained in the gastric region, indicating better retentive power. Accelerated stability studies showed sufficient formulation stability even after 3 months of storage. All these studies depict that the floating gastro-retentive system could be used as an alternative to the innovator formulation.