Evaluation of a two-dimensional Moire-free antiscatter grid for cone-beam computed tomography.

BACKGROUND: Scatter radiation is a traditional problem in cone-beam computed tomography (CBCT). Accordingly, numerous methods have been researched for scatter reduction in terms of software- or hardware-based solutions. The concept of a two-dimensional antiscatter grid (2D-ASG) has been shown to provide a solution to the scatter reduction in CBCT. However, the use of an ASG makes it challenging to use in clinical CBCT systems because it causes Moire artifacts of the image. PURPOSE: We have developed a Moire-free 2D-ASG that was designed to solve the Moire artifact and the scatter radiation problems. We provide the experimental results pertaining to the image quality measurements from the evaluation of the 2D-ASG compared with those obtained from a one-dimensional antiscatter grid (1D-ASG) and no antiscatter grid (No-ASG) to demonstrate the quantitative extent of the improvements. METHODS: The 2D-ASG, fabricated based on a sawing process with a graphite body, was prepared to evaluate image quality improvements. Projection images for Pro-CT MK II phantom were acquired using the CBCT testbed of sample rotation type and reconstructed by Feldkamp-Davis-Kress (FDK) algorithm without any filters. We measured the contrast-to-noise ratio (CNR) and uniformity index for the cupping artifacts of the 2D-ASG, 1D-ASG, and No-ASG cases. RESULTS: 2D-ASG considerably reduced the cupping artifacts owing to the scatter reduction compared with the 1D-ASG and No-ASG cases. The cupping artifacts were reduced by 85% in the 2D-ASG compared with No-ASG, while the cupping artifacts were reduced by 63% in 1D-ASG compared with No-ASG. The 2D-ASG also yielded a CNR improvement. The average CNR improvements for eight insert materials were 47% in the 2D-ASG compared with No-ASG, while the CNR was improved by 36% in the 1D-ASG compared with No-ASG. CONCLUSIONS: We demonstrated that the Moire-free 2D-ASG improved the image quality by removing scatter radiation in CBCT compared with 1D-ASG and No-ASG. We believe that the Moire-free 2D-ASG can become one of the effective ways to solve the scatter radiation problem in CBCT images because it provides usability and has the potential to have synergistic effects on other methods, such as bow-tie filter and scatter correction.

The Identification and Quantitative Analysis of Unusual Keto-Carotenoids in Ripe Fruits of Maclura tricuspidate and Its Potential as a Valuable Source of Cryptocapsin.

Ripe fruits of Maclura tricuspidata (MT) are used as food material and a natural colorant in Korea. Although MT fruits have a deep red color due to carotenoid-like pigments, their chemical nature has not been explored in detail so far. The present study aimed at elucidating the chemical structures and composition of carotenoids in MT fruits and changes at different maturity stages. Two carotenoids from saponified MT fruit extract were isolated using repeated silica gel column chromatography. Based on interpretations of spectroscopic data, these compounds were determined as keto-carotenoids, i.e., capsanthin (3,3'-dihydroxy-ß,κ-caroten-6'-one) and cryptocapsin (3'-hydroxy-ß,κ-caroten-6'-one), and the contents of individual carotenoids were quantified with HPLC based on calibration curves obtained from authentic standards. The contents of capsanthin and cryptocapsin in the sample of saponified MT fruits were 57.65 ± 1.97 µg/g and 171.66 ± 4.85 µg/g as dry weight base (dw). The majority of these keto-carotenoids in the MT fruits were present in esterified forms with lauric, myristic or palmitic acid rather than in their free forms. The results also showed that esterification of these compounds occurred starting from early stage (yellow-brownish stage) of maturation. Considering the high cryptocapsin content, MT fruits can be applied as a potentially valuable source of cryptocapsin for food and medicinal application as well as a source of provitamin A.

Bilateral Facial Weakness with Distal Paresthesia Following COVID-19 Vaccination: A Scoping Review for an Atypical Variant of Guillain-Barré Syndrome.

Background and Purpose: Recent population-based studies from the US and UK have identified an increase in the occurrence of Guillain-Barré syndrome (GBS) following coronavirus disease 2019 (COVID-19) vaccination. However, the localized variant of GBS might be underestimated due to its rarity and atypical features. We aimed to identify and characterize bilateral facial weakness with distal paresthesia (BFWdp) as a GBS variant following COVID-19 vaccination. Materials and Methods: Relevant studies published during the COVID-19 pandemic were searched and identified in the MEDLINE, Embase, and other databases. Results: This review found that 18 BFWdp cases presented characteristics similar to previous BFWdp cases as defined in the literature: male dominance, frequent albuminocytological dissociation, and acute inflammatory demyelinating neuropathy pattern. In contrast, facial nerve enhancement on brain MRI and antiganglioside antibody positivity were often observed in BFWdp following COVID-19 vaccination. Conclusions: The mechanism of BFWdp following COVID-19 vaccination appears to be somewhat different from that of sporadic BFWdp. Neurological syndromes with rare incidence and difficulty in diagnosis should be considered adverse events of COVID-19 vaccination.

Thermal stability of Si/SiC/ta-C composite coatings and improvement of tribological properties through high-temperature annealing.

We report the structure, mechanical properties, thermal stability, and durability of Si/SiC/ta-C composite (Si-ta-C) coatings fabricated using simultaneous filtered cathodic vacuum arc deposition and direct current unbalanced magnetron sputtering. Si concentration of 1.25-6.04 at.% was achieved by increasing the unbalanced magnetron sputtering power from 25 to 175 W. Si addition provided functionality to the coating, such as heat resistance, while retaining the high hardness of ta-C coatings. The Si-ta-C coatings were stable up to 600 °C regardless of the Si content, while the coating containing 3.85 at.% Si was stable up to 700 °C. The friction behavior and mechanical properties were dependent on the coating film before and after annealing at 100-200 °C; however, annealing at 300-400 °C decreased disk wear and increased counterpart wear due to an increase in film hardness on account of an endothermic reaction that increased the number of Si-C bonds. This indicates that the basic hardness characteristics of the ta-C coating and the high-temperature structural change of the Si-ta-C coating are important for ensuring high-temperature durability. These characteristics were verified through the low coefficient of friction and wear rate of the 1.25 at.% Si-ta-C coating after annealing at 500 °C.

Identification of Novel Parishin Compounds from the Twig of Maclura tricuspidata and Comparative Analysis of Parishin Derivatives in Different Parts.

Parishin compounds are rare polyphenolic glucosides mainly found in the rhizome of the traditional Chinese medicinal plant, Gastrodia elata. These constituents are reported to have several biological and pharmacological activities. In the present study, two novel parishin derivatives not previously reported as plant-based phytochemicals were identified from a twig of Maclura tricuspidata (MT) and two new compounds were elucidated as 1-(4-(ß-d-glucopyranosyloxy)benzyl)-3-hydroxy-3-methylpentane-1,5-dioate (named macluraparishin E) and 1,3-bis(4-(ß-d-glucopyranosyloxy)benzyl)-3-hydroxy-3-methylpentane- 1,5-dioate (macluraparishin C), based on the experimental data obtained by UV-Visible (UV-Vis) spectroscopy, high performance liquid chromatography-quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS) and nuclear magnetic resonance (NMR) spectroscopy. Additionally, gastrodin, parishin A and parishin B were positively identified by spectroscopic evidence and the comparison of HPLC retention time with the corresponding authentic standards. Gastrodin, parishin A and parishin B, macluraparishin E and macluraparishin C were found to be the most abundant constituents in the MT twig. The compositions and contents of these constituents were found to vary depending on the different parts of the MT plant. In particular, the contents of parishin A, parishin B, macluraparishin C and macluraparishin E were higher in the twig, bark and root than in the leaves, xylem and fruit.

Superior mesenteric artery syndrome treated successfully by endoscopy-assisted jejunal feeding tube placement.

We report the case of a 31-year-old man with superior mesenteric artery syndrome after reoperation due to postoperative complications from rectal cancer. Although initial total parenteral nutrition (TPN) therapy failed, he underwent endoscopy-assisted feeding tube placement without complications instead of surgery. After 2 weeks of dual feeding (enteral feeding and TPN), he improved, gaining 6 kg; and an oral diet was advanced.

Temporal Variation Dominates in Local Carabid Beetle Communities in Korean Mountains.

Spatial and temporal variation in ecological environments may result in spatial and temporal variation in communities. Temporal studies of biodiversity are essential for forecasting future changes in community structure and ecosystem function. Therefore, determining the mechanisms that drive temporal change in communities remains an important and interesting challenge in ecology. We quantified spatial and temporal variations in carabid beetle communities and site-specific environmental factors for 5 years at nine study sites on three mountains in the Baekdudaegan Mountain Range, Korea. Carabid beetle communities exhibited significant temporal variation, which was larger than spatial variations between and within mountains. Environmental factors mostly varied between sites within mountains. Community variation was only weakly associated with environmental factors at wide scales, i.e., between sites on three mountains, but was strongly associated at narrow spatial scales, i.e., between sites within one mountain. Our results indicate that temporal variation in communities occurs in response to variations in the local climate, and that the patterns of temporal variation differ between mountains. Thus, temporal surveys of insect communities and climates at local scales are important for predicting temporal changes in the communities.

Effects of silicon doping on low-friction and high-hardness diamond-like carbon coating via filtered cathodic vacuum arc deposition.

In this study, silicon (Si) was doped on a tetrahedral amorphous carbon (ta-C) coating and the tribological characteristics of the resulting Si-doped diamond-like carbon (DLC; a-C:Si:H) were investigated against a SUJ2 ball. The Si fraction in the coating was varied from 0 to ~ 20 at.% by increasing the trimethylsilane gas flow rate during filtered cathodic vacuum arc deposition. The coefficient of friction (CoF) showed no obvious change when the Si fraction was less than ~ 7 at.%. However, after Si doping, it significantly decreased when the Si fraction was greater than ~ 8 at.%. The running-in period also decreased to less than 1000 cycles after Si doping. The rapid formation of Si-rich debris and transfer layer led to the fabrication of a low-friction tribofilm, which was induced by the tribochemical reaction with moisture under ambient conditions. When the Si fraction was ~ 17 at.%, the lowest CoF of less than 0.05 was obtained. Further Si doping beyond the critical point led to the destruction of the film because of reduced hardness.

Comparison of Phytochemicals and Antioxidant Activities of Berries Cultivated in Korea: Identification of Phenolic Compounds in Aronia by HPLC/Q-TOF MS.

Aronia, blueberry, Korean raspberry, blackberry, mulberry, and red raspberry fruits cultivated in Korea were evaluated for total phenol content (TPC), total flavonoid content (TFC), total anthocyanin, and ascorbic acid content. All berries were assayed for antioxidant activities determined as 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline)-6 sulphonic acid free radical scavenging activity, and ferric reducing antioxidant power. Individual phenolic compounds in aronia were also identified using high-performance liquid chromatography/quadrupole-time of flight mass spectrometry. TPC, TFC, total anthocyanin, and ascorbic acid contents of the fruit samples ranged from 17.05 to 135.55 mg of gallic acid equivalent/g dry weight (dw), 1.0 to 8.59 mg of rutin equivalent/g dw, 2.55 to 24.43 mg of cyanidin-3-O-glucoside equivalent/g dw, and 3.14 to 19.45 mg of ascorbic acid equivalent/g dw, respec-tively. Aronia and Korean raspberry showed the highest TPC, TFC, and total anthocyanin while red raspberry had the high-est ascorbic acid content. Antioxidant activities showed positive correlations to phenolic and anthocyanin contents suggesting antioxidant activity of berry samples is due to these compounds. Aronia had the highest antioxidant value among fruits.

Antihypertensive effects of Korean wild simulated ginseng (Sanyangsam) extracts in spontaneously hypertensive rats.

Ginseng possesses a wide spectrum of medicinal effects and has widely been used in traditional medicine for thousands of years. In this study, the antihypertensive effect of Korean wild simulated ginseng in spontaneously hypertensive rats was investigated. Three groups of hypertensive rats-a group without wild simulated ginseng treatment; another group treated with 100 mg of wild simulated ginseng extract/kg of body weight; and the other group treated with 200 mg of wild simulated ginseng extract/kg of body weight were tested over 8 weeks. The two wild simulated ginseng-treated groups showed significantly (p < 0.05) reduced systolic blood pressure at 4 and 6 weeks of wild simulated ginseng treatment. However, the wild simulated ginseng treatment did not adversely affect the food intake, serum electrolytes, osmolality, heart weight, heart rate, and the cross-section of the aorta as well as enzyme activities. The results suggested that Korean wild simulated ginseng is effectively used for reducing high systolic blood pressure in hypertensive patients without causing adverse health effects.

Changes of Phytochemical Components (Urushiols, Polyphenols, Gallotannins) and Antioxidant Capacity during Fomitella fraxinea⁻Mediated Fermentation of Toxicodendron vernicifluum Bark.

The stem bark of Toxicodendron vernicifluum (TVSB) has been widely used as a traditional herbal medicine and food ingredients in Korea. However, its application has been restricted due to its potential to cause allergies. Moreover, there is limited data available on the qualitative and quantitative changes in the composition of its phytochemicals during fermentation. Although the Formitella fraxinea-mediated fermentation method has been reported as an effective detoxification tool, changes to its bioactive components and the antioxidant activity that takes place during its fermentation process have not yet been fully elucidated. This study aimed to investigate the dynamic changes of urushiols, bioactive compounds, and antioxidant properties during the fermentation of TVSB by mushroom F. fraxinea. The contents of urushiols, total polyphenols, and individual flavonoids (fisetin, fustin, sulfuretin, and butein) and 1,2,3,4,6-penta-O-galloyl-ß-D-glucose (PGG) significantly decreased during the first 10 days of fermentation, with only a slight decrease thereafter until 22 days. Free radical scavenging activities using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6- sulfonic acid) (ABTS), and ferric reducing/antioxidant power (FRAP) as an antioxidant function also decreased significantly during the first six to nine days of fermentation followed by a gentle decrease up until 22 days. These findings can be helpful in optimizing the F. fraxinea⁻mediated fermentation process of TVSB and developing functional foods with reduced allergy using fermented TVSB.

Tetrahedral amorphous carbon prepared filter cathodic vacuum arc for hole transport layers in perovskite solar cells and quantum dots LEDs.

(ta-C) films coated through the filtered cathodic vacuum arc (FCVA) process as a hole transport layer (HTL) for perovskite solar cells (PSCs) and quantum dot light-emitting diodes (QDLEDs). The p-type ta-C film has several remarkable features, including ease of fabrication without the need for thermal annealing, reasonable electrical conductivity, optical transmittance, and a high work function. X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy examinations show that the electrical properties (sp3/sp2 hybridized bond) and work function of the ta-C HTL are appropriate for PSCs and QDLEDs. In addition, in order to correlate the performance of the devices, the optical, surface morphological, and structural properties of the FCVA-grown ta-C films with different thicknesses (5 ~ 20 nm) deposited on the ITO anode are investigated in detail. The optimized ta-C film with a thickness of 5 nm deposited on the ITO anode had a sheet resistance of 10.33 Ω-2, a resistivity of 1.34 × 10-4 Ω cm, and an optical transmittance of 88.97%. Compared to the reference PSC with p-NiO HTL, the PSC with 5 nm thick ta-C HTL yielded a higher power conversion efficiency (PCE, 10.53%) due to its improved fill factor. Further, the performance of QDLEDs with 5 nm thick ta-C hole injection layers (HIL) showed better than the performance of QDLEDs with different ta-C thicknesses. It is concluded that ta-C films have the potential to serve as HTL and HIL in next-generation PSCs and QDLEDs.

Antioxidant properties of Korean major persimmon (Diospyros kaki) leaves.

Persimmon is one of the most common native fruits of South Korea and its leaves are well known to be used in pharmaceuticals, cosmetics as well as beverages. The aim of this study was to compare the antioxidant properties of Korean major persimmon leaves on the basis of drying methods (hot air drying and freeze-drying) and harvesting time. Persimmon leaves from five cultivars ('Sangju-dungsi', 'Sangam-dungsi', 'Cheongdobansi', 'Gabjubaekmok' and 'Suhong') were harvested in late May and late June followed by blanching and drying. Results depicted that, persimmon leaves harvested in late May had the highest amount of antioxidants content compared to the late June. No significant difference was found between HAD and FD treatment with respect to total phenol, total flavonoid, tannin content, ABTS and DPPH radical-scavenging activity. Finally, it can be concluded that 'Gabjubaekmok' persimmon leaves collected during late May and dried by hot air are richer in antioxidants.

Effective passivation of Ag nanowire network by transparent tetrahedral amorphous carbon film for flexible and transparent thin film heaters.

We developed effective passivation method of flexible Ag nanowire (NW) network electrodes using transparent tetrahedral amorphous carbon (ta-C) film prepared by filtered cathode vacuum arc (FCVA) coating. Even at room temperature process of FCVA, the ta-C passivation layer effectively protect Ag NW network electrode and improved the ambient stability of Ag NW network without change of sheet resistance of Ag NW network. In addition, ta-C coated Ag NW electrode showed identical critical inner and outer bending radius to bare Ag NW due to the thin thickness of ta-C passivation layer. The time-temperature profiles demonstrate that the performance of the transparent and flexible thin film heater (TFH) with the ta-C/Ag NW network is better than that of a TFH with Ag NW electrodes due to thermal stability of FCVA grown ta-C layer. In addition, the transparent and flexible TFHs with ta-C/Ag NW showed robustness against external force due to its high hardness and wear resistance. This indicates that the FCVA coated ta-C is promising passivation and protective layer for chemically weak Ag NW network electrodes against sulfur in ambient.

Specificity and genetic diversity of xylose-fermenting Scheffersomyces yeasts associated with small blue stag beetles of the genus Platycerus in East Asia.

Among insect-fungus relationships, xylose-fermenting Scheffersomyces yeasts are well known for their potential in utilizing wood hemicelluloses and their association with various wood-feeding insects. However, their specificity to host insects or strain-level diversity within host species has not been clearly elucidated. In the insect family Lucanidae, larvae usually feed on decaying wood, and adult females consistently possess a fungus-storage organ, called the mycangium, near the abdominal tip. Here the authors investigated host-symbiont relationships between Scheffersomyces yeast symbionts and small blue stag beetles of the genus Platycerus (Coleoptera: Lucanidae) in East Asia by using intergenic spacer (IGS) region as a genetic marker. All yeast strains isolated from the female mycangium of three Platycerus species, P. hongwonpyoi from Korea and P. acuticollis and P. delicatulus from Japan, were allied to Scheffersomyces segobiensis based on the sequences of the nrDNA 26S and internal transcribed spacer (ITS), in which no sequence difference was observed among those strains. However, IGS regions showed clear genetic differentiation within the yeast symbionts of P. hongwonpyoi, as well as between those of Korean and Japanese Platycerus species. In the IGS sequences, nucleotide substitutions were mainly distributed in the whole stretch of IGS1 and the anterior half of IGS2, whereas nucleotide gaps were localized at IGS1 and the middle of IGS2. Despite the conserved association between the Platycerus beetles and the specific strains of S. segobiensis in East Asia, geophylogenetic divergence patterns of the yeast symbionts were not concordant with those of the insect hosts.

Effect of pre-treatment and extraction conditions on the antioxidant properties of persimmon (Diospyros kaki) leaves.

Persimmon is a very delicious fruit and the leaves of this tree are used as a traditional drug. This study aimed to investigate the effects of drying method (hot air and freeze-drying), extraction temperature (80, 90 and 100 °C) and extraction time (10, 30, 60 and 120 min) and harvest stage (flowering and fruiting) on the antioxidant contents and antioxidant activity of persimmon leaves. The results showed that the highest antioxidants were obtained in both methods of drying. Also, 100 °C for 120 min of extraction gave the highest antioxidant contents, but with no significant difference compared to 90 °C for 60 min of extraction. Persimmon leaves collected during flowering stage had the maximum amount of antioxidants compared to the fruiting stage. Finally, it can be said that persimmon leaves harvested during flowering stage and treated by hot air drying with these extraction conditions (90 °C for 60 min) are richer in bioactive compounds.

Co-occurrence of ecologically equivalent cryptic species of spider wasps.

Many cryptic species have been discovered in various taxonomic groups based on molecular phylogenetic analyses and mating experiments. Some sympatric cryptic species share equivalent resources, which contradicts the competitive exclusion principle. Two major theories have been proposed to explain the apparent lack of competitive exclusion, i.e. niche-based coexistence and neutral model, but a conclusive explanation is lacking. Here, we report the co-occurrence of cryptic spider wasp species appearing to be ecologically equivalent. Molecular phylogenetic analyses and mating experiments revealed that three phylogenetically closely related species are found sympatrically in Japan. These species share the same resources for larval food, and two of the species have the same niche for nesting sites, indicating a lack of competitive exclusion. This evidence may suggest that ecologically equivalent species can co-occur stably if their shared resources are sufficiently abundant that they cannot be over-exploited.

Four cases of abnormal neuropsychological findings in children with high blood methylmercury concentrations.

BACKGROUND: Methylmercury (MeHg) easily crosses the blood-brain barrier and accumulates in the brain. Accumulated MeHg will cause neurological symptoms. We report four pediatric cases of neuropsychological findings with high blood MeHg concentrations. CASE PRESENTATION: Four children were admitted for follow-up study because their total mercury (THg) concentration in the blood was found to be high during a national survey. Case 1 was a 9-year-old female with a 16.6 µg/ℓ blood THg concentration in the survey. During admission, the blood THg, hair THg, and blood MeHg concentration(mercury indices) were 21.4 µg/ℓ, 7.2 µg/g, and 20.1 µg/ℓ, respectively. In our neuropsychological examination, cognitive impairment and attention deficit were observed. Her diet included fish intake 2-3 times per week, and she had been diagnosed with epilepsy at 3 years of age. Case 2 was a 12-year-old male with blood THg of 15.4 µg/ℓ in the survey and the mercury indices were 12.7 µg/ℓ, 5.7 µg/g, and 11.8 µg/ℓ, respectively, on admission. He was also observed to have attention-deficit/hyperactivity disorder. Case 3 was a 10-year-old male child with blood THg of 17.4 µg/ℓ in the survey, and the mercury indices on admission were 21.6 µg/ℓ, 7.5 µg/g and 21.5 µg/ℓ, respectively. In his case, mild attention deficit was observed. Case 4 was a 9-year-old male with blood THg of 20.6 µg/ℓ in the survey and the mercury indices were 18.9 µg/ℓ, 8.3 µg/g, and 14.4 µg/ℓ, respectively, on admission. Mild attention difficulty was observed. CONCLUSION: We suggest that fish consumption may be the main source of MeHg exposure, and that MeHg may have been the cause of the neuropsychological deficits in these cases.

Effects of electrode geometry on the ion beam extraction of closed drift type anode layer linear ion source.

Closed drift type anode layer linear ion source was investigated with focusing on the electrode geometry effects on ion beam emission and anode layer formation. In the electrode geometry, the discharge gap between anode and cathode plays an important role to control anode layer formation as well as electron generation. When the discharge gap is increased from 2 to 3 mm, the ion current density was enhanced from 0.9 to 1.35 mA∕cm(2). Computational simulation by using an object oriented particle in cell showed that the discharge volume was extended due to enhanced electron generation and the electric field at the anode layer was enhanced from 1.32 to 1.52 MV∕cm.

Development of new strains and related SCAR markers for an edible mushroom, Hypsizygus marmoreus.

New fast-growing and less bitter varieties of Hypsizygus marmoreus were developed by crossing monokaryotic mycelia from a commercial strain (Hm1-1) and a wild strain (Hm3-10). Six of the better tasting new strains with a shorter cultivation period were selected from 400 crosses in a large-scale cultivation experiment. We attempted to develop sequence characterized amplified region (SCAR) markers to identify the new strain from other commercial strains. For the SCAR markers, we conducted molecular genetic analysis on a wild strain and the eight most cultivated H. marmoreus strains collected from various areas in East Asia by randomly amplified polymorphic DNA. Ten unique DNA bands for a commercial Hm1-1 strain and the Hm3-10 strain were extracted and their sequences were determined. Primer sets were designed based on the determined sequences. PCR reactions with the primer sets revealed that four primer sets successfully discriminated the new strains from other commercial strains and are thus suitable for commercial purposes.