Atomic sawtooth-like metal films for vdW-layered single-crystal growth.

Atomic sawtooth surfaces have emerged as a versatile platform for growth of single-crystal van der Waals layered materials. However, the mechanism governing the formation of single-crystal atomic sawtooth metal (copper or gold) films on hard substrates (tungsten or molybdenum) remains a puzzle. In this study, we aim to elucidate the formation mechanism of atomic sawtooth metal films during melting-solidification process. Utilizing molecular dynamics, we unveil that the solidification of the liquid copper initiates at a high-index tungsten facet with higher interfacial energy. Subsequent tungsten facets follow energetically favourable pathways of forming single-crystal atomic sawtooth copper film during the solidification process near melting temperature. Formation of atomic sawtooth copper film is guaranteed with a film thickness exceeding the grain size of polycrystalline tungsten substrate. We further demonstrate the successful growth of centimeter-scale single-crystal monolayer hexagonal boron nitride films on atomic sawtooth copper films and explore their potential as efficient oxygen barrier.

Microstructure and Mechanical Properties of Laser Direct Energy Deposited Martensitic Stainless Steel 410.

The aim of this work is to study the phase transformations, microstructures, and mechanical properties of martensitic stainless steel (MSS) 410 deposits produced by laser powder-directed energy deposition (LP-DED) additive manufacturing. The LP-DED MSS 410 deposits underwent post-heat treatment, which included austenitizing at 980 °C for 3 h, followed by different tempering treatments at the temperatures of 250, 600, and 750 °C for 5 h, respectively. The analyses of phase transformations and microstructural evolutions of LP-DED MSS 410 were carried out using X-ray diffraction, SEM-EDS, and EBSD. Vickers hardness and tensile strength properties were also measured to analyze the effects of the different tempering heat treatments. It revealed that the as-built MSS 410 has very fine lath martensite, high hardness of about 480 HV1.0, and tensile strength of about 1280 MPa, but elongation was much lower than the post-heat-treated ones. Precipitations of chromium carbide (Cr23C6) were most commonly observed at the grain boundaries and the entire matrix at the tempering temperatures of 600 °C and 750 °C. In general, the tensile strength decreased from 1381 MPa to 688 MPa as tempering temperatures increased to 750 °C from 250 °C. Additionally, as the tempering temperature increased, the chromium carbide and tempered martensite structures became coarser.

Universal Platform for Robust Dual-Atom Doped 2D Catalysts with Superior Hydrogen Evolution in Wide pH Media.

Layered 2D transition metal dichalcogenides (TMDs) have been suggested as efficient substitutes for Pt-group metal electrocatalysts in the hydrogen evolution reaction (HER). However, poor catalytic activities in neutral and alkaline electrolytes considerably hinder their practical applications. Furthermore, the weak adhesion between TMDs and electrodes often impedes long-term durability and thus requires a binder. Here, a universal platform is reported for robust dual-atom doped 2D electrocatalysts with superior HER performance over a wide pH range media. V:Co-ReS2 on a wafer scale is directly grown on oxidized Ti foil by a liquid-phase precursor-assisted approach and subsequently used as highly efficient electrocatalysts. The catalytic performance surpasses that of Pt group metals in a high current regime (≥ 100 mA cm-2) at pH ≥ 7, with a high durability of more than 70 h in all media at 200 mA cm-2. First-principles calculations reveal that V:Co dual doping in ReS2 significantly reduces the water dissociation barrier and simultaneously enables the material to achieve the thermoneutral Gibbs free energy for hydrogen adsorption.

Updates on parasite infection prevalence in the Joseon period based on parasitological studies of human coprolites isolated from archaeological sites in the cities of Euijeongbu, Gumi, and Wonju.

Parasite infection rates estimated by examining ancient coprolites can provide insights into parasitism in Joseon society. Using newly discovered Joseon period cases is essential to regularly update the parasite infection rates and reinforce the reliability of our previous estimations. In the present study, we investigated parasite infections in Joseon coprolites newly isolated from the cities of Euijeongbu, Gumi, and Wonju. We then updated the overall parasite infection rates of Joseon period samples (n= 30) as follows: 86.7% (26/30) for Trichuris trichiura, 56.7% (17/30) for Ascaris lumbricoides, 30.0% (9/30) for Clonorchis sinensis, and 30.0% (9/30) for Paragonimus westermani. The parasite infection rates in the Joseon society, estimated through coprolite examination, were very similar to those determined previously despite the addition of new cases to the existing data pool.

Wafer-Scale Epitaxial Growth of an Atomically Thin Single-Crystal Insulator as a Substrate of Two-Dimensional Material Field-Effect Transistors.

As the electron mobility of two-dimensional (2D) materials is dependent on an insulating substrate, the nonuniform surface charge and morphology of silicon dioxide (SiO2) layers degrade the electron mobility of 2D materials. Here, we demonstrate that an atomically thin single-crystal insulating layer of silicon oxynitride (SiON) can be grown epitaxially on a SiC wafer at a wafer scale and find that the electron mobility of graphene field-effect transistors on the SiON layer is 1.5 times higher than that of graphene field-effect transistors on typical SiO2 films. Microscale and nanoscale void defects caused by heterostructure growth were eliminated for the wafer-scale growth of the single-crystal SiON layer. The single-crystal SiON layer can be grown on a SiC wafer with a single thermal process. This simple fabrication process, compatible with commercial semiconductor fabrication processes, makes the layer an excellent replacement for the SiO2/Si wafer.

Revealing Joseon period People's single nucleotide polymorphism associated with lactase gene by ancient DNA analysis of human remains from archaeological sites in Korea.

Lactase non-persistence (LNP), one of the causes of lactose intolerance, is related to lactase gene associated single nucleotide polymorphisms (SNPs). Since the frequency of LNP varies by ethnic group and country, the research to reveal the presence or absence of LNP for specific people has been conducted worldwide. However, in East Asia, the study of lactase gene associated SNPs have not been sufficiently examined so far using ancient human specimens from archaeological sites. In our study of Joseon period human remains (n=14), we successfully revealed genetic information of lactase gene associated SNPs (rs1679771596, rs41525747, rs4988236, rs4988235, rs41380347, rs869051967, rs145946881 and rs182549), further confirming that as for eight SNPs, the pre-modern Korean people had a lactase non-persistent genotype. Our report contributes to the establishment of LNP associated SNP analysis technique that can be useful in forthcoming studies on human bones and mummy samples from East Asian archaeological sites.

Revisiting diaphragmatic hernia of Joseon period Korean mummy by three-dimensional liver and heart segmentation and model reconstruction.

A three-dimensional (3D) segmentation and model reconstruction is a specialized tool to reveal spatial interrelationship between multiple internal organs by generating images without overlapping structures. This technique can also be applicable to mummy studies, but related reports have so far been very rare. In this study, we applied 3D segmentation and model reconstruction to computed tomography images of a Korean mummy with congenital diaphragmatic hernia. As originally revealed by the autopsy in 2013, the current 3D reconstruction reveals that the mummy's heart is shifted to the left due to the liver pushing up to thoracic cavity thorough diaphragmatic hernial defect. We can generate 3D images by calling up the data exclusively from mummy's target organs, thus minimizing the confusion of diagnosis that could be caused by overlapping organs.

Genetic analysis of mitochondrial DNA from ancient Equus caballus bones found at archaeological site of Joseon dynasty period capital area.

OBJECTIVE: To understand the domestication and spread of horses in history, genetic information is essential. However, mitogenetic traits of ancient or medieval horses have yet to be comprehensively revealed, especially for East Asia. This study thus set out to reveal the maternal lineage of skeletal horse remains retrieved from a 15th century archaeological site (Gongpyeongdong) at Old Seoul City in South Korea. METHODS: We extracted DNA from the femur of Equus caballus (SNU-A001) from Joseon period Gongpyeongdong site. Mitochondrial (mt) DNA (HRS 15128-16116) of E. caballus was amplified by polymerase chain reaction. Cloning and sequencing were conducted for the mtDNA amplicons. The sequencing results were analyzed by NCBI/BLAST and phylogenetic tool of MEGA7 software. RESULTS: By means of mtDNA cytochrome b and D-loop analysis, we found that the 15th century Korean horse belonged to haplogroup Q representing those horses that have historically been raised widely in East Asia. CONCLUSION: The horse is unique among domesticated animals for the remarkable impact it has on human civilization in terms of transportation and trade. Utilizing the Joseonperiod horse remains, we can obtain clues to reveal the genetic traits of Korean horse that existed before the introduction of Western horses.

GENETIC ANALYSIS OF ANCIENT CLONORCHIS SINENSIS EGGS ATTAINED FROM GORYEONG MUMMY OF JOSEON DYNASTY PERIOD.

Although Clonorchis sinensis is a parasite that still infects many people in East Asia, its genetics remain largely unknown. We conducted ancient DNA analysis of C. sinensis eggs obtained from a Joseon period mummy newly discovered in South Korea. Clonorchis sinensis DNA was amplified for internal transcribed spacer 1, cytochrome c oxidase subunit 1, and NADH dehydrogenase subunit 2 and 5 genes. The results of BLAST/NCBI showed that the consensus sequences were 98.24 to 100% identical to the modern and ancient C. sinensis sequences reported from Korea, China, Japan, and other Asian countries. Our report helps to fill in the genetic profile of ancient C. sinensis strains that infected East Asian people hundreds of years ago.

Classification of the interosseous tarsometatarsal ligaments of the foot.

BACKGROUND: The aim of this study was to clarify the anatomical features of the interosseous tarsometatarsal ligaments of foot and to classify their types based on the combinations of their ligamentous components. METHODS: Fifty feet from 27 adult Korean cadavers were dissected. RESULTS: The interosseous tarsometatarsal ligaments were observed in the first, second, and third cuneometatarsal joint spaces. The interosseous tarsometatarsal ligament of the first cuneometatarsal space consistently connected the medial cuneiform and the second metatarsal, and was accompanied by one or two accessory ligaments above (34%) and/or below (6%) the Lisfranc ligament. The interosseous tarsometatarsal ligaments of the second and third cuneometatarsal joint spaces comprised seven and five components, and were classified into five and three types depending on the number and combination of the components, respectively. CONCLUSIONS: These results are expected to advance the current knowledge on the tarsometatarsal joint and provide helpful information for more accurate and successful diagnosis and treatment of lesions at this joint.

Ancient DNA of Metagonimus yokogawai Recovered from Joseon Period Human Remains Newly Discovered at Goryeong County in South Korea.

PURPOSE: Metagonimiasis, commonly seen in East Asian countries, is a parasitic disorder caused by definitive hosts' ingestion of undercooked freshwater fishes. Recently, genetic analysis has proved 28S rRNA and cytochrome c oxidase subunit I (COI) mtDNA gene to be a successful marker differentiating species of the genus Metagonimus. In the present study, using specimens from the newly discovered Joseon Dynasty human remains of Goryeong, we obtained updated genetic data on genus Metagonimus, which was also prevalent during the Joseon period. METHODS: The ancient DNA (aDNA) was retrieved from the coprolite sample of the seventeenth century, half-mummified individual discovered at Goryeong Country, South Korea. Cloning and sequencing were performed on PCR-amplified amplicons for M. yokogawai 28S rRNA and COI mtDNA gene. The consensus sequences were used for species identification and phylogenetic analysis using NCBI/BLAST and MEGA X software. RESULTS: Based on the COI mtDNA gene region, the Goryeong sequence was confirmed as belonging to M. yokogawai, as it was shown to form a separate cluster with other M. yokogawai taxa that are distinct also from M. takahashii and M. miyatai. CONCLUSION: In a series of our genetic analyses on genus Metagonimus using samples retrieved from Joseon-period cases, aDNA sequences of genus Metagonimus revealed in South Korea thus far are those of M. yokogawai, but not of M. miyatai or M. takahashii yet.

The three muscle layers in the pyloric sphincter and their possible function during antropyloroduodenal motility.

This study was conducted to determine the muscular arrangement of the human pyloric sphincter using a comprehensive approach that involved microdissection, histology, and microcomputed tomography (micro-CT). The stomachs of 80 embalmed Korean adult cadavers were obtained. In all specimens, loose muscular tissue of the innermost aspect of the sphincter wall ran aborally, forming the newly found inner longitudinal muscle bundles, entered the duodenum, and connected with the nearby circular bundles. In all specimens, approximately one-third of the outer longitudinal layer of the sphincter entered its inner circular layer, divided the circular layer into several parts, and finally connected with the circular bundles. Anatomical findings around the sphincter were confirmed in micro-CT images. The sphincter wall comprised three layers: an inner layer of longitudinal bundles, a middle layer of major circular and minor longitudinal bundles, and an outer layer of longitudinal bundles. The stomach outer longitudinal bundles were connected to the sphincter circular bundles. The inner longitudinal bundles of the sphincter were connected to the adjacent circular bundles of the duodenum.

Helminth Eggs Detected in Soil Samples of a Possible Toilet Structure Found at the Capital Area of Ancient Baekje Kingdom of Korea.

Although research conducted in East Asia has uncovered parasite eggs from ancient toilets or cesspits, data accumulated to date needs to be supplemented by more archaeoparasitological studies. We examined a total of 21 soil samples from a toilet-like structure at the Hwajisan site, a Baekje-period royal villa, in present-day Korea. At least 4 species of helminth eggs, i.e., Trichuris trichiura, Ascaris lumbricoides, Clonorchis sinensis, and Trichuris sp. (or Trichuris vulpis) were detected in 3 sediment samples of the structure that was likely a toilet used by Baekje nobles. The eggs of T. trichiura were found in all 3 samples (no. 1, 4, and 5); and A. lumbricoides eggs were detected in 2 samples (no. 4 and 5). C. sinensis and T. vulpis-like eggs were found in no. 5 sample. From the findings of this study, we can suppose that the soil-transmitted helminths were prevalent in ancient Korean people, including the nobles of Baekje Kingdom during the 5th to 7th century.

Two Helminthic Cases of Human Mummy Remains from Joseon-Period Graves in Korea.

Our previous research on coprolite specimens from the mummies of Joseon Dynasty (1392-1910 CE) has revealed various species of parasite eggs. Herein, we added 2 new helminthic cases of human remains from Joseon-period graves in the Republic of Korea (Korea). The organic materials precipitated on the hip bones of 2 half-mummied cases (Goryeong and Gwangmyeong cases) were collected, rehydrated, and examined by a microscope. In the sample from Goryeong-gun (gun=County), ova of Trichuris trichiura, Clonorchis sinensis, and Metagonimus spp. were detected, and eggs of T. trichiura and A. lumbricoides were found from the sample of Gwangmyeong-si (si=City). By adding this outcome to the existing data pool, we confirm our previous estimates of Joseon-period parasite infection rates. The overall rates of A. lumbricoides, T. trichiura, and C. sinensis decreased dramatically from Joseon to the modern period. In Goryeong mummy specimen, we also found Metagonimus spp. eggs that has rarely been detected in archaeological samples so far.

Elemental Sub-Lattice Occupation and Microstructural Evolution in γ/γ' Co-12Ti-4Mo-Cr Alloys.

We report on comparative atom probe tomography investigations of γ/γ'-forming Co­12Ti­4Mo­Cr alloys. Moderate additions of Cr (2 and 4 at%) reduced the γ/γ' lattice misfit and increased the γ' volume fraction of a Co­12Ti­4Mo alloy significantly. These microstructural changes were accompanied by changes in the elemental partitioning between γ and γ' and site-occupancy in γ'. Spatial distribution maps revealed that Mo occupied both Co and Ti sub-lattice sites in γ'. In agreement with the experimental data, thermodynamic calculations predicted a stronger tendency for Mo to occupy the Co-sites than for Cr and an increase in Cr fraction on the Ti-sites with increasing Cr content.

Epitaxial Single-Crystal Growth of Transition Metal Dichalcogenide Monolayers via the Atomic Sawtooth Au Surface.

Growth of 2D van der Waals layered single-crystal (SC) films is highly desired not only to manifest the intrinsic physical and chemical properties of materials, but also to enable the development of unprecedented devices for industrial applications. While wafer-scale SC hexagonal boron nitride film has been successfully grown, an ideal growth platform for diatomic transition metal dichalcogenide (TMdC) films has not been established to date. Here, the SC growth of TMdC monolayers on a centimeter scale via the atomic sawtooth gold surface as a universal growth template is reported. The atomic tooth-gullet surface is constructed by the one-step solidification of liquid gold, evidenced by transmission electron microscopy. The anisotropic adsorption energy of the TMdC cluster, confirmed by density-functional calculations, prevails at the periodic atomic-step edge to yield unidirectional epitaxial growth of triangular TMdC grains, eventually forming the SC film, regardless of the Miller indices. Growth using the atomic sawtooth gold surface as a universal growth template is demonstrated for several TMdC monolayer films, including WS2 , WSe2 , MoS2 , the MoSe2 /WSe2 heterostructure, and W1- x Mox S2 alloys. This strategy provides a general avenue for the SC growth of diatomic van der Waals heterostructures on a wafer scale, to further facilitate the applications of TMdCs in post-silicon technology.

Newly-found channels in the interatrial septum of the heart by dissection, histologic evaluation, and three-dimensional microcomputed tomography.

A minute thrombus can pass through a small type of interatrial communication, which can result in a stroke or transient ischemic attack and several associated symptoms. This study sought to investigate a new type of interatrial communication. Thirty-one hearts from embalmed adult cadavers were investigated. Each interatrial channels (IACs) was classified as either an open or obstructed channel according to the connection of each hole on the right and left surfaces of the interatrial septum. Open channels were found in two specimens (6.5%). Both open and obstructed IACs followed tortuous courses through the interatrial septum. On the right surface of the interatrial septum, the hole was usually found adjacent to the left border of the interatrial septum between the opening of the superior vena cava into the right atrium and the superior margin of the fossa ovalis. Conversely, holes on the left surface of the interatrial septum were usually found in the upper and middle parts adjacent to the left border of the interatrial septum. This novel finding is expected to support our understanding of the onset of possible symptoms such as stroke in the absence of classical atrial septal defects.

Metagonimus yokogawai Ancient DNA Recovered from 16th- to 17th-Century Korean Mummy Feces of the Joseon Dynasty.

Metagonimiasis is foodborne intestinal parasitism occurring by the definitive hosts' ingestion of raw or undercooked fish, mostly commonly sweetfish. Most Metagonimus infection is caused by Metagonimus yokogawai but also rarely by Metagonimus takahashii as well as Metagonimus miyatai. Despite recent molecular work on Metagonimus spp., there are still insufficient data to reveal the genetic characteristics of ancient M. yokogawai in a wide geo-historical scope. In this study, we were successful in the analysis of M. yokogawai ancient DNA (aDNA) using coprolite samples retrieved from 16th- to 17th-century Korean mummies. In BLAST and phylogenetic analyses, M. yokogawai 28S rDNA of Korean mummies were clustered along with the 28S rDNA taxa of M. takahashii and M. miyatai in GenBank. Conversely, the cytochrome c oxidase subunit I (COI) of M. yokogawai aDNA from Korean mummies was distinctly clustered apart from M. takahashii and M. miyatai sequences. This study is the first report of its kind to identify M. yokogawai aDNA retrieved from the archaeological specimens and confirms the usefulness of COI in molecular diagnosis of M. yokogawai. Considering the rarity of reports on the genetics of genus Metagonimus spp., our study will be fundamental for the future study of M. yokogawai paleogenetics.

Heights and spatial relationships of the facial muscles acting on the nasolabial fold by dissection and three-dimensional microcomputed tomography.

The aim of this study was to clarify the heights and spatial relationships of the facial muscles acting on the nasolabial fold (NLF) by dissection and three-dimensional microcomputed tomography for use in aesthetic treatments. This study used 56 specimens from 34 embalmed adult Korean. A reference line (RF) was set to imitate the NLF after removing the skin, from the superior point of the alar facial crease to the lateral point of the orbicularis oris muscle at the level of the corner of the mouth. The heights and spatial relationships of the facial muscles along the RF could be categorized into five main patterns. The dominant pattern was that the levator labii superioris alaeque nasi muscle (LLSAN), levator labii superioris muscle (LLS), zygomaticus minor muscle (Zmi), and zygomaticus major muscle (Zmj) were on the medial third, medial half, middle third, and lateral third of the RF, respectively. In micro-CT imaging, beneath the skin of the medial half of the NLF, the LLSAN and Zmi fibers inserted into the dermis of the NLF and adjacent to the NLF. Beneath the skin of the middle third of the NLF, the Zmi fibers were found before the muscle inserted into the dermis of the NLF and adjacent to the NLF. Beneath the skin of the lateral third of the NLF, the lateral margin of the orbicularis oris muscle and some Zmj fibers were found at the location of the NLF. The present study utilized dissections and micro-CT to reveal the general pattern and variations of heights and spatial relationships of the facial muscles passing beneath the NLF. These findings will be useful for understanding which muscles affect specific parts of NLFs with various contours, for reducing the NLF in aesthetic treatments, and for reconstructing the NLF in cases of facial paralysis.