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Microfluidic paper-based analytical devices for antioxidant vitamins C and E in foods
Full text linkIn this study, we developed microfluidic paper-based analytical devices (μPADs) for the determination of antioxidant vitamins. The proposed μPADs utilize the reduction of metal ions by hydrophilic and hydrophobic antioxidant vitamins, which is followed by colorimetric reactions with chelating reagents. Hydrophilic vitamin C reduces Fe(III) to Fe(II) and forms a stable Fe(II)-bathophenanthroline complex in an aqueous solution. By contrast, this complex is unstable in organic solvents, and hydrophobic vitamin E requires Fe(III) and bathophenanthroline to be replaced with Cu(II) and bathocuproine. In these results, the relationship between the logarithm of a vitamin's concentration and its color intensity was linear and ranged from 4.4 to 35 mg L−1 for ascorbic acid and 50–200 mg L−1 for α-tocopherol. The limits of detection, estimated from the standard deviation of blank samples, were 3.1 mg L−1 for ascorbic acid and either 27 mg L−1 (in hexane) or 48 mg L−1 (in ethanol) for α-tocopherol. The proposed method was used to quantify vitamin C in bell peppers, mandarin oranges, kiwifruit, and lemons, as well as vitamin E in almonds, almond milk, and dietary supplements. The results demonstrate the effectiveness of these μPADs for the practical analysis of antioxidant vitamins in food samples
Bone-enhanced high contrast X-ray images derived from attenuation estimation related to ultra-low energy X-rays – An application of an energy-resolving photon-counting detector (ERPCD)
Full text linkPurpose: X-ray diagnosis in medicine is often used for bone diagnosis based on qualitative observation analysis. However, there are often cases where the contrast of bones is reduced because of the existence of soft-tissues, making it difficult to accurately diagnose the bone conditions. Although the algorithm for bone extraction images was proposed using an energy-resolving photon-counting detector (ERPCD), this algorithm can depict “one” bone material (such as hydroxyapatite under the assumption), and it is difficult to adequately depict other components. The purpose of this study is to develop an algorithm for bone-enhanced high-contrast images that can be virtually represented by the attenuation of extremely low-energy X-rays without making any special assumptions.
Methods: High-contrast images were virtually generated based on the attenuation rate of ultra-low energy X-rays. It was determined by fitting the mass attenuation coefficient (μ/ρ) curve to the X-ray attenuation values (μt values) measured at middle (30–40 keV) and high (40–60 keV) energy windows, and extrapolating the μt values to those for the low energy region (E = 5–20 keV). When performing the extrapolation, the effective atomic number (Zeff ) of the object was taken into consideration. The methodology was validated by simulating X-ray projections using a digital human body phantom. The frequency of correspondence between the pixel values in the high-contrast image and the Zeff image was analyzed for each pixel.
Results: We succeeded in creating virtual high-contrast X-ray images that reflect the image contrast of monochromatic X-rays of 5–20 keV. It was confirmed that the pixel values in the high-contrast image corresponding to an Zeff = 7.5 (soft-tissue) were completely separated from those corresponding to an Zeff = 9 (bone). The optimization of the energy related to the high contrast images was performed based on the contrast-to-noise ratio (CNR) analysis. The high contrast image with 10 keV showed a good CNR value.
Conclusions: Based on the analysis of the attenuation information of middle and high-energy X-rays measured by ERPCDs, we succeeded in creating a novel algorithm that can generate a virtual monochromatic image with high contrast
A novel wearable dosimeter system that can analyze the incident direction of X-rays for medical dosimetry – Improvements to the detector arrangements and analysis algorithm –
No full textWhen performing real-time dosimetry using an active-type dosimeter during clinical fluoroscopic procedures, angular dependence of dosimeter response should be taken into account. Our research group addressed this issue and proposed a triple-type dosimeter that can determine the incident angle of scattered X-rays. The triple-type detector consists of three active dosimeters. The two side dosimeters have slope filters to enhance the angular dependence and are intentionally tilted. The central dosimeter faces forward. The incident angle of X-rays (θin) is estimated using the signal differences between the central dosimeter and the left and/or right dosimeters. Then, the absolute dose is determined by correcting the angular dependence of the central dosimeter based on the estimated θin. In order to verify the concept of the triple-type dosimeter, we conducted a proof-of-concept experiment using clinical X-ray fluoroscopic equipment. Scattered X-rays were generated by irradiating an elliptical cylindrical water phantom. The response of the triple-type dosimeter was evaluated by rotating it to vary the incident angle of scattered X-rays generated by the water phantom. The proposed dosimetry system could estimate the θin over an angular range of ±80° (with uncertainty of 1.35°), which is 30° wider than the previous version, and successfully determined the absolute doses after correction for the angular dependence of the dosimeter. Although the active-type dosimeter had a systematic uncertainty related to the angular dependence of ±15.2 %, our system succeeded in reducing the systematic uncertainty to ±3.2 %
The vicious cycle between nutrient deficiencies and antibiotic-induced nutrient depletion at the host cell-pathogen interface: Coenzyme Q10 and omega-6 as key molecular players
Full text linkThe increasing prevalence of antibiotic resistance and pathological inflammation underscores the importance of understanding the underlying biochemical and immune processes that govern the host-pathogen interface. Nutrient deficiency, compounded by antibiotic-induced nutrient depletion, forms a vicious cycle of overt inflammation, contributing to bacterial toxin translocation in human inter-organ and intra-organs milieus. Coenzyme Q10 (CoQ10) and omega-6 linoleic acid (LA 18:2ω6) are integral to cellular membrane integrity and immune defense. However, the complex enzymatic steps at the host cell-pathogen interface remain poorly understood. This study is particularly timely, as it explores these knowledge gaps, which can inform the development of nutritional and therapeutic strategies that modulate or target these mechanisms. Using an infectious-inflamed cell co-culture model of the gut-liver axis, we exposed triple cell co-cultures of human intestinal epithelial cells (T84), macrophage-like THP-1 cells, and hepatic cells (Huh7) to linoleic acid-producing Lactobacillus casei (L. casei) and Pseudomonas aeruginosa strain PAO1 (PAO1). The cultures were incubated for 6 h in medium with or without ceftazidime antibiotic. PAO1 and L. casei exerted opposing effects on the secretion of Th1 cytokines IL-1β, IL-6, and the Th 2-type cytokine IL-10. Inoculation with PAO1 decreased CoQ10 and linoleic acid levels compared to uninfected controls. L. casei restored cellular health and biofunctionality impaired by PAO1, indicating its benefit to the host's well-being. The antibiotic ceftazidime exerted dual effects, alleviating PAO1 toxicity while marginally disrupting the beneficial effects of L. casei. Our results show how the vicious cycle of nutrient deficiency and antibiotic-induced nutrient loss reinforces pathological inflammation at the host cell-pathogen interface and highlights the need for more appropriate targeted antibiotic use that preserves essential nutrients like CoQ10 and omega-6 fatty acids. Inflammatory responses driven by opportunistic pathogens and LA-producing bacteria represent opposing immunometabolic pathways that may provide insights into novel approaches for treating infection and reducing antibiotic resistance
Experimental approach of internal dose map visualization during helical CT examinations: importance of X-ray incident direction analysis and central internal dose estimation
No full textDuring computed tomography (CT) examination, radiation exposures should be appropriately managed taking into considering the effects of bowtie filter, the heel effect and over-beaming effect. Furthermore, the analysis of an X-ray incident direction is important. The purpose of this study is to develop a procedure to obtain two-dimensional (2D) internal dose distributions based on actual measurements of surface dose distribution and central internal dose data. Experiments were conducted using a clinical CT scanner and four cylindrical polyacetal resin (POM) phantoms having diameters of 15–30 cm. The entrance surface doses and the central internal dose were measured by placing the optically stimulated luminescence (OSL) dosimeters on the surface and inner part of the phantom, respectively, during helical CT scans. The X-ray incident direction at the slice containing the dosimeter was estimated based on the noise distribution analysis of the CT image. Then, circumferential surface dose distributions were determined as a function of the X-ray incident direction. Based on these experimental data, we succeeded in visualizing the 2D dose distributions. The obtained dose distribution was inhomogeneous, clearly reflecting the influence of factors such as the heel effect. The uncertainty due to our methodology was estimated to be from 4.3 % to 7.4 %. Our methodology needs central internal dose data, and the absence of this data introduced additional systematic uncertainties of +6.9 % to −11.4 %. In conclusion, correcting for the effect of the X-ray incident directions for entrance surface dose and adding the central inner dose data can improve the reliability of the internal dose distribution
Optimization of the reconstruction kernel for temporal bone imaging using photon-counting detector CT: A combined physical and visual evaluation
No full textIntroduction: Photon-counting detector CT (PCD-CT) offers superior spatial resolution and noise characteristics compared to conventional CT. However, optimal reconstruction parameters for temporal bone imaging, especially kernel selection, remain unclear. This study aimed to identify the optimal reconstruction kernel using both objective physical image quality metrics and subjective expert assessments.
Methods: In phantom experiments, the system performance function (SPF) based on the task-based transfer function (TTF) and noise power spectrum (NPS) was calculated across 11 reconstruction kernels (Hr60–Hr98). Based on the results of the physical evaluation and clinical considerations from clinical practice, a subset of kernels was selected for visual assessment. For clinical images, two diagnostic radiologists evaluated three fine anatomical structures (i.e., stapes footplate, incudomalleolar joint, and cochlea) and overall image quality using both a ranking method and a 5-point Likert scale.
Results: TTF analysis indicated that Hr96 had the highest spatial resolution, while Hr60 showed the lowest noise in the NPS. SPF analysis identified Hr72 as providing the optimal balance between resolution and noise. Visual assessment using four reconstruction kernels (Hr60, Hr72, Hr76, and Hr84) showed that Hr76 consistently received the highest preference for overall image quality and visualization of fine structures. Statistically significant differences were observed among the kernels, with Hr60 consistently rated the lowest (p
Conclusion: The kernel Hr76 was found suitable for middle and inner ear diagnoses using PCD-CT, providing a good balance between spatial resolution and image noise. This finding provides a foundation for standardized reconstruction protocols in high-resolution temporal bone imaging.
Implications for practice: These findings support the use of Hr76 as a standard kernel for high-resolution temporal bone imaging and may contribute to protocol optimization in clinical PCD-CT practice
Molecular epidemiological investigation of the carbapenemase-producing Enterobacterales isolates in Okayama prefecture, Japan
No full textWe investigated the genetic characteristics of non-IMP type carbapenemase-producing Enterobacterales isolates detected in Japan. The isolates were found to carry diverse plasmids with high sequence similarity to those previously reported in other countries, underscoring the critical imperative for comprehensive nationwide epidemiological surveillance for the silent pandemic of the nightmare pathogen
Assessing water resources availability and crop performance under climate change in Kenya's Bura irrigation scheme using SWAT and AquaCrop
No full textThe current study focused on Tana River Basin in Kenya, home to the Bura irrigation scheme (BIS). The BIS faces water supply shortages during critical months of crop development. This study aimed to evaluate the available water resources and crop performance using the Soil and Water Assessment Tool (SWAT) and AquaCrop, respectively, under historical and future shared socioeconomic pathways (SSPs) at the BIS. SWAT estimated the total available flows (TAF) at the BIS intake, whereas AquaCrop estimated crop water requirements (CWR), yields, and water productivity (Wpet) of rice and maize at various carbon (IV) oxide (CO2) levels. The study suggested that the TAF will remain relatively low during the early critical crop development stages in the main cropping season, August-October. Maize yields remained steady over the two cropping seasons under both constant and elevated CO2 levels in the historical and future periods, as opposed to those of rice. Elevated CO2 levels led to diminishing CWR. Moreover, rice showed a stronger response to elevated CO2 than maize. As a result, maize which is less affected by variations in CO2 and temperatures and has less crop water requirements will be better suited than rice for cultivation in the BIS under climate change. To ensure a sustainable water supply in the scheme, the government should increase rainwater harvesting during periods of high TAF. Moreover, there should be a focus on introducing crops that are tolerant to water and temperature stresses and that can reap the most from the elevated CO2 levels
Effects of grain size and crystal orientation on tensile properties of pure titanium thin wires
Full text linkTo clarify the effects of the grain size and crystal orientation on the tensile properties of pure titanium thin wires, tensile and stepwise tensile tests were conducted on pure titanium wires with diameters of approximately 180 μm and different average grain sizes (52, 37, 23, and 3.8 μm). When the grain size was large, the fracture strain was significantly smaller, the variation in tensile strength was larger, and the grain size threshold for such properties was a grain-size ratio to wire diameter of 0.13 or greater. For larger grain sizes, the slip system with the highest modified Schmid factor (MSF), which is the Schmid factor divided by the critical resolved shear stress of each slip system, was activated in all 15 grains whereas for smaller grain sizes, the percentage of slip systems activated with the highest MSF was slightly lower. In addition, the fracture location in a thin wire with larger grain sizes was highly correlated with the average MSF of the grains in the cross-section
N-terminal domains and site-specific glycosylation regulate the secretion of avian melanocortin inverse agonists, agouti signaling protein (ASIP) and agouti-related protein (AGRP)
No full textAgouti signaling protein (ASIP) and agouti-related protein (AGRP) are paralogous inverse agonists of melanocortin receptors with distinct physiological roles, but their structural and biochemical properties in birds remain poorly understood. Here, we characterized chicken ASIP and AGRP proteins. Analysis of available sequences revealed that a motif resembling the mammalian proprotein convertase 1/3 (PC1/3, also known as PCSK1) cleavage site is conserved across a broad range of avian orders, but Western blot analysis of transfected Chinese hamster ovary (CHO-K1) cells and chicken hypothalamus detected no cleavage, suggesting that avian AGRP may not be post-translationally processed at this site. Chicken ASIP mRNA contains an in-frame upstream ATG (uATG) and a putative N-linked glycosylation site at Asn-42, both conserved across multiple avian orders. Overexpression in CHO-K1 cells showed that ASIP translated from either ATG produces a mature protein of the same size that is N-glycosylated at Asn-42 and exhibits markedly lower secretion efficiency than AGRP. Domain-swapping experiments revealed that the N-terminal domain reduces secretion, whereas a naturally occurring ASIP-b variant with an additional N-glycan at Asn-47 shows enhanced secretion. Proteasome inhibition increased intracellular ASIP, and endoglycosidase H (Endo H) sensitivity indicated endoplasmic reticulum (ER) retention, suggesting that the N-terminal domain limits secretion via ER-associated proteasomal degradation. These findings reveal species-specific post-translational regulation of avian melanocortin inverse agonists, in which N-terminal features and site-specific N-glycosylation determine secretion efficiency, likely contributing to their distinct roles in pigmentation and hypothalamic energy balance