• Animal Systematics, Evolution and Diversity
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• v.35 no.2
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• pp.41-48
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• 2019

Pseudacrobeles(Pseudacrobeles) variabilis(Steiner, 1936) Steiner, 1938 and P. (Bunobus) pseudolatus($Hern{\acute{a}}ndez$, 1990) De Ley, Siddiqi and $Bostr{\ddot{o}}m$, 1993 belonging to the family Cephalobidae Filipjev, 1934 are newly reported from South Korea. Pseudacrobeles (Pseudacrobeles) variabilis is distinguished from its congeners by having distinctly setiform cephalic probolae, three rounded or knob-shaped labial probolae and longer female tail. Pseudacrobeles (Bunobus) pseudolatus is distinguished from its congeners by having visibly lateral lips, a short post-uterine sac, elongated conoid tail in the female, and acute mucro on the tails of both sexes. In this study, details of the morphological characters and morphometrics of Korean populations of P. (P.) variabilis and P. (B.) pseudolatus are described and illustrated based on optical microscopy.

• Progress in Superconductivity and Cryogenics
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• v.25 no.2
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• pp.1-4
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• 2023

Over the past decade, the exploration of high-temperature superconductivity and the discovery of a wide range of exotic superconducting states in Fe-based materials have propelled condensed matter physics research to new frontiers. These materials exhibit intriguing phenomena arising from their multiband electronic structure, strongly orbital-dependent effects, extremely small Fermi energy, electronic nematicity, and topological aspects. Among the various factors influencing their superconducting properties, high magnetic fields play a crucial role as a control knob capable of disrupting the subtle balance between the spin, charge, lattice, and orbital degrees of freedom, leading to the emergence of various exotic superconducting states. In this review, we provide an overview of the current understanding of the exotic superconducting states observed in Fe-based superconductors, with a particular focus on FeSe and Sr₂VO₃FeAs, under the influence of high magnetic fields.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.1-10
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• 1984

This study was performed to observe the chronological changes in the tegumental structure of M. yokogawai using scanning electron microscope. The subjected worms were encysted metacercariae obtained from the sweetish, and 2-day, 1-week and 4-week old worms experimentally reared in albino rats. The results are as follows: 1. The tegument of encysted metacercariae showed many transverse shallow rugae, which were more remarkable in posterior half body, i.e., posterior to ventral sucker. The whole surface was armed with many scale-like spines; 7~8 pointed ones on anterior body and 2~3 pointed on posterior body. The ciliated knob-like papillae (Type I) were abundant around oral and ventral suckers, which grouped 2, 3 or 4 in number in most cases. A few round swellings of tegument(Type lI were observed only on oral sucker. 2. The tegumental surface of 2-day old worms showed deeper rugae, and the anterior half covered with knob-like processes of distal cytoplasm and the posterior half with cobblestone-like ones. Interspinous space became more wide and 9 pointed spines appeared on anterior dorsal surface. The sensory papillae enlarged but not changed in their distribution. 3. The tegument of 1-week old worms revealed knob-like cytoplasmic processes in posterior half body and velvety ones around oral sucker. The scale-like spines of anterior half body changed remarkably to the slender ones of posterior body at the level of ventral sucker. In dorsal surface, the arrangement of the Type I papillae were bilaterally symmetrical. 4. The tegument of 4-week old worms were finely differentiated and the posterior tegument covered with velvety cytoplasmic processes. The spines had remarkably grown in length and width but the density remained nearly unchanged. The papillae also became larger but their morphology and distribution were not different from younger worms. However, the round elevation of cytoplasmic ridges (Type III papilla) appeared bilaterally on inner wall of oral sucker, approximately 8 in number. From the above results, it is considered that the tegument of juvenile iH. yokogawai continued to differentiate until 4 weeks after infection.

• Journal of Korean Philosophical Society
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• v.146
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• pp.307-328
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• 2018

The use of thought experiments has a long history in many disciplines including science. In the field of philosophy, thought experiments have frequently appeared in the pre-existing literature on the contemporary Analytic Philosophy. A thought experiment refers to a synthetic environment where the designer of the experiment-with his or her intuition and imagination-tests common-sense knowledge. It can be understood as a conceptual tool for testing the validity of the common understanding of an issue or a phenomenon. However, we are not certain about the usefulness or efficacy of a thought experiment in knowledge production. The design of a thought experiment is meant to lure readers into believing as intended by the experiment itself. Thus, regardless of the purpose of a thought experiment, many readers who encounter the experiment could feel deceived. In this paper, to analyze the logic of thought experiments and to seek the source of uneasiness the readers and critics may feel about thought experiments, I draw lessons from three renowned thought-experiments: Thomson's 'ailing violinist', Putnam's 'brain in a vat', and Searle's 'Chinese room'. Imaginative thought experiments are usually constructed around a gap between the reality and the knowledge/information at hand. From the three experiments, several lessons can be learned. First, the evidence of the existence of a gap provided via thought experiments can serve as arguments for counterfactual situations. At the same time, the credibility and efficacy of the thought experiments can be damaged as soon as the thought-experiments are carried out with inappropriate and/or murky directions regarding the procedures of the experiment or the background of the study. According to D. R. Hofstadter and D. C. Dennett(1981), the 'knob setting' in a thought experiment can be altered in the middle of a simulation of the experimental condition, and then the implications of the thought experiment change altogether, indicating that an entirely different conclusion can be deduced from thought experiment. Lastly, some pre-suppositions and bias of the experiment designers play a considerable role in the validity and the chances of success of a thought experiment; thus, it is recommended that the experiment-designers refrain from exercising too much of their imagination in order to avoid contaminating the design of the experiment and/or wrongly accepting preconceived/misguided conclusions.

• Parasites, Hosts and Diseases
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• v.22 no.1
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• pp.21-29
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• 1984

A scanning eletron microscopic study was performed to observe the tegumental surface of adult Fibricola seoulensis. The adult worms were collected from the small intestine of mice 5 days to 3 weeks after experimental infection with the metacercariae. The metacercariae were obtained from the viscera of the snakes, Matrix tigrina lateralis, by artificial digestion technique. The results were as follows: 1. The tegument of anterior body was covered with cobblestone-like cytoplasmic processes and that of posterior body showed finger-like processes. The posterior body had 4-5 large transverse wrinklings which formed many discontinued shallow rugae. 2. The entire surface of anterior body was regularly arranged with the spines of which tips diverged into 3 to 4 points. They were densely packed in anterior mid-median portion of dorsal surface where appeared a few spines indented upto 5 points. Farther laterally and posteriorly from this portion, the pointed spines were more sparse and became single tipped and extended to anterior one-third of posterior body, 3. The posterior surface of oral sucker was armed with 50-60 spines having 2-3 tips and ventral sucker also covered with such spines. On anteriormost dorsal surface arranged 60-70 spade-shaped spines. The tribocytic organ was armed with many stout recurved pile-like spines arranged radially. 4. There were 3 types of sensory papillae. The ciliated knob-like (Type I) papillae were almost bilaterally symmetrical in ventral and dorsal surfaces of anterior body, and abundant especially aroundbases of oral and ventral suckers, tribocytic organ, and in lateral margins of anterior body. About 24 non-ciliated round swellings (Type II) were observed around each lip of oral and ventral suckers. The plate-like elevated papilla without cilium (Type III) was found to distribute only in posterior body. These 3 types of papillae seem to be tangoreceptive and/or rheoreceptive in function when their morphology and distributions are considered.

• Applied Microscopy
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• v.37 no.4
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• pp.219-230
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• 2007

The morphological effects of intranasal zinc sulfate(5% solution) irrigation on the mouse olfactory epithelium and the regeneration process of olfactory receptor cells following nasal irrigation were studied with scanning and transmission electron microscope. The results were as follows: 1. The septal epithelium except some basal cells was wholly detached from the basement membrane, during the first 6 to 24 hours after 5% zinc sulfate irrigation. 2. 3 days after $ZnSO_4$ treatment, two layered septal epithelium was formed from basal cells. And microvilli were observed in the apical epithelium of newly formed olfactory epithelial cells. 3. 5 days after treatment, a lot of centrosomes and basal bodies were observed in the olfactory receptor cells, and cilia were lined up between microvilli on the apical membrane of olfactory receptor cells. And immature olfactory knob was first observed in the newly formed olfactory receptor cells. Mature olfactory knob was observed 1 week after treatment. 4. There are very many mature olfactory knobs in the olfactory receptor cells 2 weeks after intranasal zinc sulfate irrigation. These results support that treatment with 5% zinc sulfate is a good experimental model for the regeneration of mammalian nervous tissues because this method could thoroughly detach the septal epithelium. During the regeneration of olfactory receptor cells, the surface membrane of the olfactory receptor cells widen the surface with the microvilli. Then cilia, which arranged in a line, substituted for the microvilli. The part of the surface membrane with cilia protruded and finally formed the olfactory vesicle.

• Parasites, Hosts and Diseases
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• v.27 no.1
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• pp.57-66
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• 1989

A scanning electron microscopic study was performed to observe the tegumental ultrastructures of Paragonimus iloktuenensis according to its developmental stages. The metacercariae were obtained from the liver of the brackish water crab, Sesarma dehaani. Juvenile and adult p. iloktsuenensis were recovered from the experimental rats on 2, 4 and 8 weeks after infection. The findings were summarized as follows: 1. The encysted metacercariae were charaeteristically gourd-shape, with their whole body surface beset with numerous spade-shape spines. The Barge, type II sensory papillae (non-ciliated round swellings) were arranged along the rim of the oral and ventral suckers, 11~12 and 6~8 in numbers respectively, 2. Two-week old juvenile worms, recovered chieay from the liver of the experimental rats, were slender in body shape: with their ventral sucker near the anterior one-third level. The distribution of tegumental spines was less dense than in the encysted metacercariae. The spines were with 1~2 pointed tips and 3~.4 longitudinal splits. Numerous ciliated knob-like, type I papillae were observed in both sides of the oral sucker, and 6 large, type If papillae were arranged along the rim of the ventral sucker. 3. Four week old worms, recovered from the thoracic cavity and/or lung parenchyme of the experimental rats, were thicker than wide in body configuration, and their ventral sucker was located near the anterior one.fourth level. The tegumental spines at ventral surface were grouped, each group with 3~5 aggregated ones. The type I and type II papillae (small-sired) were distributed chiefly around the rim of two suckers. 4. Adult (eight-week old) worms, recovered from the capsules in the lung parenchyme, were very stout, and covered densely with bearfoot like spines. At dorsal surface, cobblestone-like cytoplasmic processes were well-developed, with many tegumental spines embedded in them. It was observed in this study that the tegument of p. iloktsuenensis continued to change and differentiate as the worms grew to be adults.

• Applied Microscopy
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• v.12 no.2
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• pp.11-22
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• 1982

The morphological development of Mycoplasma pneumoniae attached to solid surfaces was examined by light and electron microscopies. Critical point drying and carbon replication techniques revealed that during the growth cycle of developing microcolonies, the morphological form coincided with the pH of the culture. M. pneumoniae appeared to have a well defined morphology associated with age of the culture. The organisms were dimorphic, with round cells capable of reproduction and segments consisting of a spindle shaped body with one pointed and one knob-like end. Starting with single cells, there were the following stages in the development of a culture: replication stage through binary fission and segmentation, stage of confluency, and a degeneration stage into rough spherical forms. The round cells appearrd to replicate by binary fission during the lag and early log phases of growth, while spindle segments replicated by segmentation during most of the logarithmic growth. The growth of the filaments and replication of the segments occured at the knob-like ends, showing a type of polarity, and formed a meshwork across the surface. This development could be cycled under favorable growth conditions, but the culture aged and when the conditions became adverse(e.g. pH 6.8 or lower), filamentous cells converted to spherical forms, losing their reproductive capability.

• Korean Journal of Ichthyology
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• v.33 no.1
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• pp.1-7
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• 2021

Using stereo, light, and scanning electron microscopes, we researched the anatomical and histological structure of Chaenogobius gulosus's olfactory organ and compared it to those of sympatric gobies Luciogobius guttatus and Favonigobius gymnauchen. Results revealed the following common characteristics: i) tubular anterior nostril (AN) and flat posterior nostril (PN), ii) a single longitudinal lamella, iii) two accessory nasal sacs (ANS, ethmoidal and lacrimal), iv) abundant sensory epithelium lymphatic cells (LC), v) an eosinophil cell, and vi) a ciliary length a quarter of the knob diameter in the olfactory receptor neuron (ORN). Some characteristics are specific to C. gulosus and different from the other two gobies: i) 0.5~1.0 mm AN and 0.2~0.5 mm PN (vs. 0.2~0.3 mm and 0.2~0.3 mm in L. guttatus; 0.2~0.4 mm and 0.1~0.3 mm in F. gymnauchen), ii) two ANS (vs. absence in L. guttatus; two in F. gymnauchen), iii) abundant LC (vs. low in L. guttatus and F. gymnauchen), iv) low density non-sensory cilia on the lamellar surface (vs. high in L. guttatus; low in F. gymnauchen), and v) a quarter ciliary length to knob diameter ratio in the ORN (vs. mixture of a quarter to equal ratio in L. guttatus; two or three times in F. gymnauchen). From these results, we confirmed the C. gulosus olfactory organ has adapted anatomically and histologically to the sand-rock tidal zone.

• Parasites, Hosts and Diseases
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• v.24 no.1
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• pp.63-70
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• 1986

The tegumental ultrastructures oi Echinostoma hortense adults were observed by scanning electron microscopy. The worms of 4 weeks of age were harvested from albino rats experimentally infected with the metacercariae obtained from the loach. The results were as follows: 1. The worms were leaf-like and their anterior end portion, including oral sucker and head crown, ventrally curved to face posteriorly. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. 2. The oral sucker had roundly swollen (type I ) sensory papillae on the ventral half of its lip and mini-ciliated knob-like (type I ) sensory papillae, arranged in 2∼3 rows, on the dorsal outer surface. 3. Aspinous ventral sucker had many of type I papillae arranged in a circular band on its outer surface. The tegument around the genital opening was of similar feature to the ventral sucker, but sensory papillae were hardly found around the former. 4. Scale-like spines with broad base and round tip were distributed densely on the tegument anterior to the ventral sucker but they became sparse in posterior half of the ventral surface, finally to disappear at posterior extremity. A few number of type I papillae were observed on the ventral surface. The results suggest that the tegument of 5. hortense is similar to that of other echinostomes etapecially 5. revolutum. But the number and arrangement of collar spines, and/or the type and distribution of sensory papillae seem characteristic features of E. hortense differed from other echinostomes.