• The Korean Journal of Malacology
• /
• v.27 no.2
• /
• pp.149-157
• /
• 2011

Some characteristics of the formations of acrosomal vesicles during the late stage of spermatids during spermiogenesis and taxonomical charateristics of sperm morphology in male two species (Saxidomus purpurata and Meretrix petechialis) in the family Veneridae were investigated by electron microscope observations. In two species, the morphologies of the spermatozoa have the primitive type and are similar to those of other bivalves in that it contains a short midpiece with five mitochondria surrounding the centrioles. The morphologies of the sperm nuclear types of S. purpurata and M. petechialis in Veneridae have the curved cylindrical and cylinderical type, respectively. And the acrosome shapes of two species are the same cap-shape type. In particular, the axial filament is not found in the lumen of the acrosome of two species, however, subacrosomal material are observed in the subacrosomal spaces between the anterior nuclear fossa and the acrosomal vesicle of two species. The spermatozoon of S. purpurata is approximately 46-$52{\mu}m$ in length, including a curved sperm nucleus (about $3.75{\mu}m$ in length), a long acrosome (about $0.40{\mu}m$ in length),and a tail flagellum (about 45-$47{\mu}m$ long). And the spermatozoon of M. petechialis is approximately 47-$50{\mu}m$ in length including a slightly curved sperm nucleus (about $1.50{\mu}m$ in length), an acrosome (about $0.56{\mu}m$ in length) and tail flagellum (44-$48{\mu}m$ in length). In two species, the axoneme of the sperm tail flagellum of each species consists of nine pairs of microtubules at the periphery and a pair of cental doublets at the center. Therefore, the axoneme of the sperm tail flagellum shows a 9 + 2 structure. In particular, taxonomically important some charateristics of sperm morphologies of two species in the family Veneridae are acrosomal morphology of the sperm, The axial filament is not found in the acrosome as seen in a few species of the family Veneridae in the subclass Heterodonta. The acrosomal vesicle is composed of right, left basal rings and the apex part of the acrosomal vesicle. In particular, right and left basal rings show electron opaque part (region), while the apex part of the acrosomal vesicle shows electron lucent part (region). These charateristics belong to the subclass Heterodonta, unlikely a characteristic of the subclass Pteriomorphia showing all part of the acrosome being composed of electron opaque part (region). Therefore, it is easy to distinguish the families or the subclasses by the acrosomal structures. The number of mitochondria in the midpiece of the sperm of S. purpurata and M. petechialis in Veneridae are five. However, the number of mitochondria in the midpiece of the sperm in most species of Veneridae in the subclass Heterodonta are four. Therefore, the number of mitochondria of the sperm midpiece of two species are exceptionally 5, and it is only exceptional case in the species in Veneridae in the subclass Heterodonta. Except these cases, the number of mitochondria in the sperm midpiece in all families in the subclass Heterodontaare are 4, and now widely used in taxonomic analyses.

• The Korean Journal of Malacology
• /
• v.26 no.3
• /
• pp.235-244
• /
• 2010

Ultrastructural characteristics of the testis and spermatogenesis of Crassostrea gigas were investigated by Transmission and Scanning Electron microscope observations. The testis is a diffuse organ consisting of branching acini containing differentiating germ cells in a variety of stages. The acinus is surrounded by an intermitent layer of myoepithelial cells andis divided into subcompartments that are partially separated by pleomorphic accessory cells which remain in close contact with germ cells until late stages of development. these accessory cells contain a large quantity of glycogen particles and lipid droplets in the cytoplasm. Therefore, it is assumed that they are involved in the supplying of the nutrients for germ cell development, while any phenomena associated with phagocytosis of undischarged, residual sperms by lysosomes could be find in the cytoplasm of the accessory cells. The morphology of the spermatozoon has a primitive type and is similar to those of other bivalves. Mature spermatozoa consist of broad, cap-shaped acrosomal vesicle, subacrosomal material (containing axial rod embedded in a granular matrix), a oval nucleus showing deeply invaginated anteriorly, two triplet substructure centrioles surrounded by four spherical mitochondria, and satelite fibres appear to the distal centriole and plasma membrane. Spermatozoa of C. gigas resemble to those of other investigated ostreids. In particular, the anterior region of the acrosomal vesicle is transversely banded. It is assumed that differences in this acrosomal substructure are associated with the inability of fertilization between the genus Crassostrea and other genus species in Ostreidae. Therefore, we can use sperm morphology in the resolution of taxonomic relationships within the Ostreidea. The spermatozoon is approximately $42-47{\mu}m$ in length including an oval sperm nucleus (about $0.91{\mu}m$ in length), an acrosome (about $0.42{\mu}m$ in length) and tail flagellum ($40-45{\mu}m$). The axoneme of the sperm tail flagellum consists of nine pairs of microtubules at the periphery and a pair at the center. The axoneme of the sperm tail shows a 9 + 2 structure. These morphological charateristics of acrosomal vesicle belong to the family Ostreidae in the subclass Pteriomorphia.

• Korean Journal of Plant Taxonomy
• /
• v.39 no.3
• /
• pp.170-180
• /
• 2009

Somatic chromosome counts and karyotype analyses were carried out for eight taxa of Korean Allium sect. Sacculiferum. The basic chromosome number of sect. Sacculiferum was x = 8, and they could be cytologically divided into two groups, that is, a diploid group (2n = 2x = 16) containing A. thunbergii var. thunbergii, A. thunbergii var. deltoides, A. thunbergii var. teretifistulosum, A. deltoidefistulosum, A. longistylum, A. linearifolium and A. taqueti, and a tetraploid group (2n = 4x = 32) with only A. sacculiferum. All observed chromosomes were classified into metacentric, submetacentric and subtelocentric. The metacentric ones appeared in all treated taxa. One or two pairs of submetacentric chromosomes were observed in most taxa except A. sacculiferum, the unique taxon with subtelocentric chromosomes. All taxa had a pair of homologous chromosomes with satellites, and the B-chromosomes found in A. thunbergii var. thunbergii, A. deltoidefistulosum, A. sacculiferum and A. longistylum, were metacentric or telocentric. The karyotypes of A. longistylum and A. linearifolium were firstly investigated in this study. In conclusion, the somatic chromosome numbers and karyotypes for members of the sect. Sacculiferum were valuable characters in identifying taxa, investigating interspecific relationships and delimiting taxa. In addition, A. thunbergii var. teretifolium, an invalid name (homonym), was renamed as A. thunbergii var. teretifistulosum H. J. Choi & B. U. Oh.

• Korean Journal of Plant Taxonomy
• /
• v.39 no.3
• /
• pp.193-198
• /
• 2009

Chromosome analysis using karyotyping and bicolor FISH were carried out for two Maackia species (M. fauriei and M. amurensis) found in Korea. The somatic metaphase chromosome number was 2n = 2x = 18 in both, and the size of these chromosomes ranged from 3.58 to $5.82{\mu}m$. The chromosome complements consisted of two pairs of metacentric (chromosomes 1 and 7), four pairs of submetacentrics (chromosomes 4, 6, 8 and 9) and three pairs of subtelocentrics (chromosomes 2, 3 and 5) in M. fauriei but, chromosomes 4 (subtelocentric) and 7 (submetacentric) of M. amurensis have different morphology. Using bicolor FISH, a pair of 45S rDNA loci were observed for both M. fauriei and M. amurensis, but the number and site of the 5S rDNA signal were different in the two species. M. fauriei has two pairs of 5S signals on chromosomes 7 and 8 but, M. amurensis has four paris on chromosomes 3, 4, 7 and 7. Hence, the 5S rDNA is a useful FISH for Maackia species.

• Journal of Conservation Science
• /
• v.37 no.5
• /
• pp.491-504
• /
• 2021

Gwanghwamun Gate of Gyeongbokgung Palace was dismantled and relocated during the Japanese colonial period, destroyed during the Korean War, reconstructed with reinforced concrete in 1968, and finally erected at its present location in 2010. A pair of Haechi statues located in front of Gwanghwamun was dismantled and relocated several times, and the statues have yet to be returned precisely to their original positions. This study assesses the historical accuracy of their current placement under the Gwanghwamun Square Restructuring Project of the Seoul Metropolitan Government and the Cultural Heritage Administration based on archival photos from the early 1900s, and proposes a method to estimate the original positions of the Haechi through image analysis of contemporary photographs and recent digital camera photos. We estimated the original position of the Haechi before the Japanese colonial period by identifying the shooting location of the archival photo and reproducing contemporary photographs by calculating the angle and distance to the Haechi from the shooting location. The leftmost and rightmost Haechi were originally located about 9.6 m to the east and 7.4 m to the north and about 1.9 m to the west and 8.0 m to the north, respectively, of their current location indicators. As the first attempt to determine the original location of a building and its accessories using archival photos, this study launches a new scientific methodology for the restoration of cultural properties.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.11
• /
• pp.893-900
• /
• 2021

In this study, air density in a narrow test section is measured using a laser absorption spectroscopy system that detects oxygen absorption lines. An absorption line pair at 13156.28 and 13156.62 cm^-1 are detected. A gas chamber with a height of 40 mm is used as a narrow test section. A triangular spiral-shaped laser path is applied in the gas chamber to amplify absorption strength by extending laser beam path length. A well-known logarithm amplifier and a secondary amplifier are used to electrically amplify absorption signal. An AC-coupling is applied after the logarithm amplifier for signal saturation prevention and noise suppression. Procedure of calculating spectral absorbance from output signal is introduced considering the logarithm amplifier circuit configuration. Air density is determined by fitting the theoretically calculated spectral absorbance to the measured spectral absorbance. Test conditions with room temperature and a pressure range of 10~100 kPa are made in a gas chamber using a Bourdon pressure gauge. It is confirmed that air density in a narrow test section can be measured within a 16 % error through absorption signal amplification using a triangular spiral-shaped beam path and a logarithm amplifier.

• Korean Journal of Optics and Photonics
• /
• v.32 no.4
• /
• pp.147-152
• /
• 2021

We report high-power continuous-wave operation of a Yb-doped fiber laser at 1070 nm, pumped by high-power laser diodes at 976 nm. Based on theoretical calculation of the stimulated Raman scattering and temperature distribution in the fiber, we construct a bidirectionally pumped Yb-fiberlaser system incorporating a pair of fiber Bragg gratings and a cladding light stripper. The fiber laser yields 3.0 kW of continuous-wave output at 1070 nm in a diffraction-limited beam with M² ≈ 1.26 for 4.1 kW of incident pump power, corresponding to a slope efficiency of 81.5%. The prospects for further power scaling are discussed.

• Asian Spine Journal
• /
• v.12 no.6
• /
• pp.973-980
• /
• 2018

Study Design: Retrospective review. Purpose: To identify the trends in stimulator use, pair those trends with various grafting materials, and determine the influence of stimulators on the risk of revision surgery. Overview of Literature: A large number of studies has reported beneficial effects of electromagnetic energy in healing long bone fractures. However, there are few clinical studies regarding the use of electrical stimulators in spinal fusion. Methods: We used insurance billing codes to identify patients with lumbar disc degeneration who underwent anterior lumbar interbody fusion (ALIF). Comparisons between patients who did and did not receive electrical stimulators following surgery were performed using logistic regression analysis, chi-square test, and odds ratio (OR) analysis. Results: Approximately 19% of the patients (495/2,613) received external stimulators following ALIF surgery. There was a slight increase in stimulator use from 2008 to 2014 (multi-level $R^2=0.08$, single-level $R^2=0.05$). Patients who underwent multi-level procedures were more likely to receive stimulators than patients who underwent single-level procedures (p<0.05; OR, 3.72; 95% confidence interval, 3.02-4.57). Grafting options associated with most frequent stimulator use were bone marrow aspirates (BMA) plus autograft or allograft for single-level and allograft alone for multi-level procedures. In both cohorts, patients treated with bone morphogenetic proteins were least likely to receive electrical stimulators (p<0.05). Patients who received stimulation generally had higher reimbursements. Concurrent posterior lumbar fusion (PLF) (ALIF+PLF) increased the likelihood of receiving stimulators (p<0.05). Patients who received electrical stimulators had similar revision rates as those who did not receive stimulation (p>0.05), except those in the multilevel ALIF+PLF cohort, wherein the patients who underwent stimulation had higher rates of revision surgery. Conclusions: Concurrent PLF or multi-level procedures increased patients' likelihood of receiving stimulators, however, the presence of comorbidities did not. Patients who received BMA plus autograft or allograft were more likely to receive stimulation. Patients with and without bone stimulators had similar rates of revision surgery.

• Korean Journal of Breeding Science
• /
• v.43 no.5
• /
• pp.422-429
• /
• 2011

This study was conducted to investigate the genetic diversity and to develop a technique for cultivar identification using SSR markers in grapevine. Thirty Korean bred and introduced grapevine cultivars were evaluated by 28 SSR markers. A total of 143 alleles were produced ranging from 2 to 8 alleles with an average of 5.1 alleles per locus. Polymorphic information contents (PIC) were ranged from 0.666 (VVIp02) to 0.975 (VVIn33 and VVIn62) with an average of 0.882. UPGMA (unweighted pair-group method arithmetic average) clustering analysis based on genetic distances using 143 alleles classified 30 grapevine cultivars into 7 clusters by similarity index of 0.685. Similarity values among the tested grapevine cultivars ranged from 0.575 to 1.00, and the average similarity value was 0.661. The similarity index was the highest (1.00) between 'Jinok' and 'Campbell Early', and the lowest (0.575) between 'Alden' and 'Narsha'. The genetic relationships among the 30 studied grapevine cultivars were basically consistent with the known pedigree. The three SSR markers sets (VVIn61, VVIt60, and VVIu20) selected from 28 primers were differentiated all grapevine cultivars except for 'Jinok' and 'Campbell Early'. Five cultivars ('Narsha, 'Alden', 'Dutchess', 'Pione', and 'Muscat Hamburg') were identified by VVIn61 at the first step. Then 21 cultivars including 'Hongsodam' by VVIt60 at the second step and 2 cultivars ('Heukbosuck' and 'Suok') by VVIu20 at the third step were identified. These markers could be used as a reliable tool for the identification of Korean grapevine cultivars.

• Korean Journal of Breeding Science
• /
• v.41 no.4
• /
• pp.444-450
• /
• 2009

Amplified fragment length polymorphism (AFLP) marker was utilized for evaluation of genetic diversity of 60 pear germplasms. Twenty selective AFLP primer pairs generated a total of 522 polymorphic amplification products. From UPGMA (unweighted pair-group method arithmetic average) cluster analysis by using polymorphic bands, the pear germplasms were divided into four clusters by similarity index of 0.691. The first cluster (I) included European pears belonging to Pyrus communis and wild species such as P. nivalis and P. cordata. The second cluster (II) included Ussurian pea pears belonging to P. betulaefolia and P. fauriei. The third cluster (III) included pea pears belonging to P. calleryana and P. koehnei. Most of germplasms belonging to P. pyrifolia and P. ussuriensis, and interspecific hybrids were included in the fourth (IV) cluster. Therefore pear germplasms originated from East Asia were closely related to P. pyrifolia and P. ussuriensis. Similarity values among the tested pear germplasms ranged from 0.584 to 0.879, and the average similarity value was 0.686.