Controlled dissolution of a single ion from a salt interface.

Interactions between monatomic ions and water molecules are fundamental to understanding the hydration of complex polyatomic ions and ionic process. Among the simplest and well-established ion-related reactions is dissolution of salt in water, which is an endothermic process requiring an increase in entropy. Extensive efforts have been made to date; however, most studies at single-ion level have been limited to theoretical approaches. Here, we demonstrate the salt dissolution process by manipulating a single water molecule at an under-coordinated site of a sodium chloride film. Manipulation of molecule in a controlled manner enables us to understand ion-water interaction as well as dynamics of water molecules at NaCl interfaces, which are responsible for the selective dissolution of anions. The water dipole polarizes the anion in the NaCl ionic crystal, resulting in strong anion-water interaction and weakening of the ionic bonds. Our results provide insights into a simple but important elementary step of the single-ion chemistry, which may be useful in ion-related sciences and technologies.

Unstable Expansion: The Development of the Military Medical Evacuation Chain in Korea, 1948-1953.

This research examines the expansion and characteristics of the Korean Army's chain of medical evacuation in 1948-1953. The most important goal of the chain of medical evacuation was to conserve fighting strength, which cannot be achieved only by sending the sick and wounded to the rear for treatment. It was more important to maintain as many mission-capable wounded soldiers on the frontline. Therefore, triage for conserving strength was the priority in the evacuation process, and military doctors conducting triage played a significant role. Focusing on military doctors, this article studies the instability of the Korean Army's medical evacuation chain. Although Korea was liberated from Japanese colonial rule in August 1945, Korea had no army or army medical services. With the support of KMAG, the Korean Army was able to build a nationwide evacuation chain during the Korean War. However, the expansion of the medical evacuation chain resulted in instability. At the heart of the instability was manpower, rather than organization and transportation. Koreans had almost no experience with the military medical services before 1948, and during the Korean War, most doctors, who had been conscripted after the outbreak of the war, were not trained as military doctors. Therefore, the Korean Army had no other choice but to conduct medical evacuations using mobilized civilian doctors who were not sufficiently trained as military doctors. The escalating war revealed the problems of civilian doctors in military uniforms. Unlike the goal of the chain of medical evacuation, they easily evacuated patients and were reluctant to release patients to return to their duties. Korean Army doctors who were not sufficiently trained as military doctors struggled between the goals of military medical services and those of medical care. Consequently, the military doctors and the instability of the medical evacuation chain during the Korean War reflect the fundamental tension between war and medicine.

High temperature phases of borophene: borophene glass and liquid.

Borophene is a family of two-dimensional (2D) boron materials containing many isomers with different hole concentrations and distributions in a triangular lattice. Although it has been widely studied theoretically and some have been synthesized experimentally, their thermodynamic properties are still unexplored. Based on density functional theory (DFT), we developed an accurate potential for the kinetic Monte Carlo (kMC) simulations of borophene. Through extensive kMC simulations, new phases were discovered, such as the glass state of borophene, liquid borophene and borophene with large holes. A phase diagram of borophene is constructed to guide future experiments on borophene materials at high temperature.

Cryopreservation of Pig Semen Using a Quercetin-Supplemented Freezing Extender.

Reactive oxygen species (ROS) produced during freeze−thaw procedures cause oxidative damage to the sperm, reducing fertility. We aimed to improve the post-thaw quality of pig sperm by quercetin (QRN) supplementation to reduce the cryodamage associated with the freeze−thaw procedure. Four equal aliquots of pooled boar semen were diluted with a freezing extender supplemented with different concentrations of QRN (0, 25, 50, and 100 µM) and then were subjected to cryopreservation in liquid nitrogen. Semen analysis was performed following 7 days of cryopreservation. Results demonstrated that the semen samples supplemented with 50 µM QRN significantly improved the post-thaw sperm quality than those subjected to other supplementations (p < 0.05). Semen samples supplemented with 50 µM QRN showed significantly improved plasma membrane functional integrity (47.5 ± 1.4 vs. 43.1 ± 4.1, 45.3 ± 1.7, and 44.1 ± 1.4) and acrosome integrity (73.6 ± 3.4 vs. 66.3 ± 2.4, 66.7 ± 3.6, and 68.3 ± 32.9) as compared to the control, 25 µM, and 100 µM QRN groups, respectively. The mitochondrial activity of the 50 µM QRN group was greater than control and 25 µM QRN groups (43.0 ± 1.0 vs. 39.1 ± 0.9 and 41.9 ± 1.0) but showed no difference with the 100 µM QRN group. Moreover, the 50 µM QRN group showed a higher sperm number displaced to 1 cm and 3 cm points in the artificial mucus than other groups. Therefore, supplementing the freezing extender with QRN can serve as an effective tool to reduce the magnitude of oxidative damage associated with sperm freezing.

A New Measurement Method for High Voltages Applied to an Ion Trap Generated by an RF Resonator.

A new method is proposed to measure unknown amplitudes of radio frequency (RF) voltages applied to ion traps, using a pre-calibrated voltage divider with RF shielding. In contrast to previous approaches that estimate the applied voltage by comparing the measured secular frequencies with a numerical simulation, we propose using a pre-calibrated voltage divider to determine the absolute amplitude of large RF voltages amplified by a helical resonator. The proposed method does not require measurement of secular frequencies and completely removes uncertainty caused by limitations of numerical simulations. To experimentally demonstrate our method, we first obtained a functional relation between measured secular frequencies and large amplitudes of RF voltages using the calibrated voltage divider. A comparison of measured relations and simulation results without any fitting parameters confirmed the validity of the proposed method. Our method can be applied to most ion trap experiments. In particular, it will be an essential tool for surface ion traps which are extremely vulnerable to unknown large RF voltages and for improving the accuracy of numerical simulations for ion trap experiments.

Observation of Hong-Ou-Mandel interference with scalable Yb+-photon interfaces.

We present a compact optical design for a scalable trapped ion quantum processor employing a single high numerical aperture lens for the excitation of ions and collection of photons, both of which are essential for remote entanglement generation. We verified the design by performing a quantum interference experiment between two photons generated by two sets of the proposed design and observed a 82(3) % suppression of coincidence within 8.13 ns time window when the two photons became indistinguishable. This design can be extended for the simultaneous generation of multiple pairs of entangled qubits with existing fiber-array devices.

Trends and Prospects of Studies on the Modern History of Medicine in Korea: the Rise of Socio-historical Perspective and the Decline of Nationalist Dichotomy.

In the 2010s, research on modern history of medicine in Korea has yielded notably outcomes. There have been social historical inquiries investigating the organic relationship between medicine and society, and there has been a study overcoming the traditional nationalistic dichotomous approach. A social historical perspective has been used to analyze the issues of knowledge and politics; the time period of its application was clustered around the colonial period. The condition of colonialism is both important and convenient for analyzing how and to what extent medicine, which is usually deemed neutral, contains a will of authority. Building on existing research, an attempt to understand a subject based on a combination of various elements or from various angles is needed. Accumulating empirical data is important to further advance related research. It is necessary to verify the accuracy of basic facts and build up verified facts. Sometimes theories are applied to research on the history of medicine. However, they are merely a passive application of existing theories and fail to lead to modification and fortification of the theories based on the case of Korea, let alone the establishment of an independent theory. Accumulating empirical studies would help create a unique theory for the Korean case. To establish a new theory, characteristics of the Korean case need to be identified, which have been formed by the Korean tradition. An understanding of the modern situation inevitably leads to an interest in the tradition. Another necessary effort is to expand territories, and one of them would be to develop interests in patients and consumers.

Borophene with Large Holes.

In two-dimensional (2D) borophene, the structural transition from triangular lattice to hexagonal lattice with an increase in vacancy concentration is a basic principle of constructing various borophene isomers. Here, by performing an extensive structural search of 4239 borophene isomers with both hexagonal holes (HHs) and large holes (LHs), we show that the structural transformation from triangular lattice to borophene with large holes is energetically more favorable. Borophene isomers with LHs are more stable than those with only HHs at high vacancy concentrations (>20%) and are just slightly less stable than those with only HHs at low vacancy concentrations. This discovery greatly expands the family of 2D borophene and opens a route for synthesizing new borophene isomers.

Development and Differentiation of Epididymal Epithelial Cells in Korean Native Black Goat.

The acidic luminal environment of the epididymis is regulated by the communication networks among epididymal epithelial cells; it is necessary for sperm maturation and storage. To characterize epididymal epithelial cell differentiation, the localization and expression of hydrogen-pumping vacuolar ATPase (V-ATPase) and cytokeratin 5 (KRT5) in the clear and basal cells, respectively, of immature and mature goat epididymis and vas deferens was examined. The epididymides and vas deferens were obtained from goats aged 1, 2, and 12-14 months. To assess the localization and expression patterns of V-ATPase and KRT5 in the caput, corpus, and cauda of the epididymis and proximal vas deferens, the tissue sections were subjected to immunofluorescence labeling and observed by confocal microscopy. Both clear and basal cells progressively started to differentiate in a retrograde manner. Clear cells disappeared from the cauda region after puberty, and they were maintained only in the caput and corpus regions of the adult goat epididymis. V-ATPase and KRT5 were co-expressed in the differentiated cells located at the base of the epithelium (i.e., basal cells). This cell type-specific differentiation and distribution of the epithelial cells plays a critical role in establishing a unique luminal environment for sperm maturation and storage in the goat epididymis.

The expression and localization of V-ATPase and cytokeratin 5 during postnatal development of the pig epididymis.

OBJECTIVE: We examined the localization and expression of H+ pumping vacuolar ATPase (V-ATPase) and cytokeratin 5 (KRT5) in the epididymis of pigs, expressed in clear and basal cells, respectively, during postnatal development. METHODS: Epididymides were obtained from pigs at 1, 7, 21, 60, 120, and 180 days of age; we observed the localization and expression patterns of V-ATPase and KRT5 in the different regions of these organs, namely, the caput, corpus, and cauda. The differentiation of epididymal epithelial cells was determined by immunofluorescence labeling using cell-type-specific markers and observed using confocal microscopy. RESULTS: At postnatal day 5 (PND5), the localization of clear cells commenced migration from the cauda toward the caput. Although at PND120, goblet-shaped clear cells were detected along the entire length of the epididymis, those labeled for V-ATPase had disappeared from the corpus to cauda and were maintained only in the caput epididymis in adult pigs. In contrast, whereas basal cells labeled for KRT5 were only present in the vas deferens at birth, they were detected in all regions of the epididymis at PND60. These cells were localized at the base of the epithelium; however, no basal cells characterized by luminally extending cell projections were observed in any of the adult epididymides examined. CONCLUSION: The differentiation of clear and basal cells progressively initiates in a retrograde manner from the cauda to the caput epididymis. The cell-type-specific distribution and localization of the epithelial cells play important roles in establishing a unique luminal environment for sperm maturation and storage in the pig epididymis.

Application of molecular dynamics simulation to improve the theoretical prediction for collisional cross section of aromatic compounds with long alkyl chains in crude oils.

RATIONALE: Molecular dynamics (MD) simulations with finite temperature were performed to improve the theoretical prediction of collisional cross section (CCS) values, especially for aromatic compounds containing long alkyl chains. METHODS: In this study, the CCS values of 11 aromatic compounds with long alkyl chains were calculated by MD simulations while considering internal energy at 300, 500, and 700 K, and the results were compared with experimentally determined values. RESULTS: The CCS values calculated at higher energies showed better agreement with the experimental values. Polycyclic aromatic hydrocarbons (PAHs) such as pentacene and benz[b]anthracene were also investigated, and better agreement between the theoretical and experimental results was observed when higher temperature (or higher internal energy) was considered. CONCLUSIONS: The data presented in this study show that the internal degrees of freedom of ions must be considered to accurately predict the CCS values of aromatic compounds with a flexible structure measured by ion mobility mass spectrometry.

Fabrication and Characterization of Graphene-Based Electrochemical Sensors for Glucose Measurement.

Glucose in the blood is generally measured by electrochemical method using glucose oxidase (GOx) which acts as enzymes and reduced graphene oxide (rGO) composite. The rGO, which has low dispersibility, reduces the sensing capability of sensors. In order to solve this problem, the rGO electrodes with the addition of polyvinylpyrrolidone (PVP) have been reported. However, rGO with low electrical conductivity and mobility is not compatible to the electrochemical system. In this study, graphene with excellent electrical properties was added to PVP protected rGO. The rGO was synthesized using a Hummer and Offeman's method. Graphene was synthesized using chemical vapor deposition (CVD) with a Cu catalyst. Platinum (Pt) electrodes, Ag/AgCl, and PVP protected rGO were used as working electrode, reference electrode, and counter electrode, respectively. Surface morphology and structural properties of graphene were analyzed using atomic force microscopy (AFM), Raman spectroscopy, and Fourier transform infrared spectroscopy (FT-IR). Cyclic voltametry (CV) and I-V probe station were used to analyze the performance of the electrodes. Glucose concentration was systematically varied and the reduction current was monitored using I-V probe station.

[A study on the anti-smallpox policy of Joseon Government-General].

In the beginning of the colonial era, the Joseon Government-General's most important medical policy was related to the disease of smallpox. The Government-General reused some of policies established by the Great Han Empire. They also made an effort to improve the shortcomings in that anti-smallpox policy by phasing out technically insufficient vaccinators and by incubating female vaccinators. However, compulsory vaccination was the major component of the Government-General's anti-smallpox policy. The vaccination effort was lead by police officers and the frequency of vaccinations was increased two-fold. When the anti-smallpox policy became effective in 1910, the incidence of smallpox decreased. However, after 1919, the incidence of smallpox began to increase once more. According to the Government-General, this increase was the result of a decrease in the frequency of vaccinations. Therefore, in 1923, the Government-General increased the frequency of vaccinations from twice to three times by implementing the Joseon Cowpox Ordinance. Under this policy adults were also vaccinated. Interventions by local organizations were also expanded. However, through the end of the colonial era, smallpox never fully disappeared in Joseon. The lower-than-expected rate of vaccination has been identified as one of important reasons for the constant presence of this pathogenesis. Incomplete census registration was identified as the major reason for the decrease in the vaccination rate. Insufficient technologies for disseminating the smallpox vaccine and ambiguity with regard to the vaccine's effectiveness also prevented the people of Joseon from voluntarily obtaining their vaccinations. To increase the rate of vaccination, it was necessary to secure the cooperation of Koreans. However, that cooperation has never been harmonious. No records exist of any discussions related to the problem of smallpox or the effect of the anti-smallpox vaccination, which was a reasonable expectation for the citizens of Joseon. Moreover, the Government-General kept insisting that the Joseon citizens' ideas about the need for sanitary and effective vaccinations were insufficient. The sought-after cooperation was never easy, and this resulted in the extensive duration of outbreaks of smallpox.

[The trend and prospect of studies in the modern history of medicine in Korea].

The Korean Journal of Medical History published in 1992 provides spaces for publication to medical historians who have been growing increasingly since the 1990s, thereby stimulating studies in the modern history of medicine in Korea. Through research published in the Korean Journal of Medical History and other journals, the course through which medicine in Korea in the modern times has been formed and the content of medicine that composed that course are elucidated. This article concludes that the various research tend to posit the view that the modern history of medicine in Korea evolves through a process of accommodation with Western medicine rather than being a complete transplantation of Western medicine, and describes medicine as it is viewed by consumers rather than the operators of medicine. How government power or colonial power utilized medicine in order to stabilize their rule is also a common theme. Now, it is come time to interrogate the viewpoints and analytical methods of medical history studies. Given that medicine is one area that drives changes in Korea in contemporary times, the outcomes obtained through this field can be sufficiently utilized when studying other areas. For instance, agony over the modernity of missionary medicine being studied recently provides meaningful implications in understanding the modernity of Korea. However, the importance of substantiation should not be overlooked as theories not supported by thorough documentary evidence are weak.

[Japan's Oriental medicine policy in colonial Korea].

During its colonization of Korea, the Japanese Empire used the Western medicine as a tool for advertising its advanced culture. However, the medical workforce available in Korea was insufficient. The Rule for Uisaeng (Oriental medicine practitioner) was an ordinance decreed in 1913 with a purpose of supplementing the medical workforce. As the Oriental medicine practitioners became official medical workforce, the Japanese Empire could mobilize them in a hygienic administration such as prevention of epidemics. The Uisaengs also tried to adapt themselves to the colonial environment by studying Western medicines. However, the distrust of the Japanese Empire in Oriental medicine continued until 1920s. Manchurian Incident in 1931 brought a change. As the relationship with China aggravated, the provision of medical herb became unstable and the Japanese Empire began to encourage using Oriental medical herb following the Movement for Improving Rural Region Economy. An attempt of the Japanese Empire to utilize the medical herb resulted in a plan to make the Oriental medical herb officinal. The goal was to organize and standardize the Oriental medical herb through a research by the Medical Herb Investigation Committee. However, the medical herb on the table was the one verified by the Western medicine. That is, it was not a traditional medical herb that uses the original theory of Oriental medicine. There was a minority opinion arguing that they should study the Oriental medicine itself. However, that argument was also based on the theory and principles of the Western medicine. Even though an attempt to make full use of Uisaengs expanded as the war continued, the major medical workforce that the Japanese Empire relied on was those trained in Western medicine. In other words, the Japanese Empire did not give a full credit to the Oriental medicine during the colonial era. During the colonization, Japanese Empire used Oriental medicine under the nominal reason of lack of medical workforces. In early 1930s, a policy supporting usage of Oriental medical herb was selected. However, it does not mean that the change in policy encouraged Oriental medicine since the medical herb that the Japanese Empire supported was those that were organized and categorized according to the principles in Western medicine.

[Life and medical activities of Yun Ti Wang].

Yun Ti Wang studied medicine in England, different from other Korean medical doctors in early days. Yun, who entered medical school at Glasgow University in England in March 1919, graduated with a Bachelor of Medicine in October 1925, along with an England medical license. Yun began working as an instructor at Severance Medical College from November 1927, and received Doctor of Medicine from the College of Obstetricians and Gynecologists at Kyoto Imperial University in August 1936. After the Liberation, Yun began working as a faculty member at the medical school at Seoul University, and he also worked as a Chief of the Second Medical Clinic of the school from 1946. Yun made a great effort in order to build an integrated committee, eventually contributing to the launching of Joseon Medical Associates in 1947. He was also elected as a first president at Joseon Obstetrics and Gynecology Associates, which was organized at the same year as the Joseon Medical Associates. Yun entered military as an army surgeon in April 1949 and has worked there until he was appointed as a principal at the Army Medical School in September 1953. His contributions to the development of military medical services include the following: expansion of medical facilities in army, stable system of workforce in military medical service, launching of Medical Aid and establishment of Department of Medical Care, and introduction of new medical technologies in anesthesiology and neurosurgery, etc. The career of Yun can be largely divided into the field of gynecology and military medical services. In the gynecological field, Yun contributed to the settlement of obstetrics in Korea, by taking in charge of the obstetrics class at Severance following medical missionaries. As for the military medical services, he has contributed to the establishment of military medical system as well as to the opening of new academic areas. The impact of his activities on the establishment of military medical services is especially significant, since it was a field that no Korean citizens had access to during the colonization era.

[Chang Sei Kim's activities on public health in colonial Korea].

After graduating from Severance Medical College in 1916, Chang Sei Kim went to Shanghai to work as a missionary in a adventist hospital. The establishment of the Korean Provisional Government led him to participate in the independence movement. Educating nurses to assist the forthcoming war for independence, he seemed to realize the fact that the health of Koreans would be a key factor for achieving independence. He left for the U.S. to conduct comprehensive research on medicine. Chang Sei Kim was the first Korean to receive a Ph. D. degree of Public Health, graduating from the Johns Hopkins School of Hygiene and Public Health in 1925. He then gained an opportunity to work for Korea as a professor at Severance Medical College. His objective was the 'Reconstruction of the Korean People In Terms of Physical Constitution.' He pointed out that Koreans' weak state of health was a major reason for Korea's colonization. To gain independence, he emphasized that the Korean people should receive education on public health in order to improve the primitive conditions of sanitation. There is little doubt that Chang Sei Kim's ideas developed Heungsadan's views on medicine in terms of its stress on cultivation of ability, especially considering the fact that he was a member of the organization. As a member of the colonized who could not participate in the developing official policy, Chang Sei Kim was not able to implement his ideas fully, because an individual or a private organization could not carry out policy on public health as large a scale as the government did. Never giving up his hopes for Korean independence, he rejected requests to assume official posts in the Government-General. That was why he was particularly interested in the Self-Governing Movement in 1920s Korea. If the movement had attained its goal, he might have worked for the enhancement of sanitary environment as a director of Sanitary Department. His application for funding to establish a hygiene laboratory in Korea was rejected by Rockefeller Foundation, as the policy of foundation was to finance only government institutes, not private ones. Resigning his position at Severance Medical College in 1927. Chang Sei Kim went to Shanghai to work as a Field Director in the Council on Health Education. The council was affiliated with the Rockefeller Foundation and was founded to ameliorate the hygienic situation in China. He was well fitted to the job, because China, like Korea, shared the aim to achieve independence by promoting better health for its people and because he could be appointed as a public officer which could not happen in colonial Korea. To solve the ever-serious problems with tuberculosis in China, he went again to the U. S. to conduct research and raise money for the establishment of a sanitarium. Chang Sei Kim passed away there in 1934 at the age of 42.

[Reformation of the Medical Educational Institutes and training of general doctors during the early period of Japanese rule].

The Japanese government downgraded a Korean medical college being attached to the Daehan hospital to a medical training center blaming upon a lack of education in Korea. But the actual curriculum and the years required for completing a course of study in the Korean medical college were equivalent to those of the Japanese medical college. Furthermore, the Japanese government discarded the financial support for medical school students. So they should pay their tuitions and other stipends by themselves. The Japanese government forced a private institute to establish an endowed school by the legal act of college. It enabled to classify a medical education system with the judicial support. For the example of Severance Medical School, it reformed faculty, curriculum and facility according to the legal standard of a college act. Therefore, Severance Medical School was able to be upgraded to a medical college. But there was a limitation even for the government schools under the colonial era. It was not possible to train important medical human resource who enabled to supervise the modern medical system in Korea. On one hand, almost every important medical human resource such as a military doctor, and a professor, who should have trained in Korea in the Great Han Period, was trained in Japan. On the other hand, fostering general doctors, who practiced medicine with hands-on experience, was the purpose of medical education in Korea whether the medical school was government or private. Since the purpose of Severance Medical College was to foster general doctors, it was able to grow within the colonial medical system. The purpose of medical missionaries, who promoted the spread of gospel with the western medical support, enforced the Japanese colonial logics that the Japanese government could educate and develop Korea with the introduction of western civilization. Although it was later comparing to the government medical school. Severance Medical College enabled to certify the medical license automatically to the graduates from the school. The reason that the Japanese government allowed for Severance Medical College to issue the automatic medical license was to keep the colonial structure of Japanese in Korea.

[A history of medical license in Korea].

Medical license is to qualify a person for medical practice and to attribute him/her a privileged right in the practice. This privileged and exclusive right asks for protection from the side of a state and the state in turn needs qualified medical personnel in order to carry out her task of public health, one of the main duties of modern states. In Europe, physicians succeeded in obtaining medical license that guarantees the privileged right in a highly competitive medical market against other practitioners. The first regulation for medical license in Korea was made in 1900 when few Korean doctors trained in Western medicine was in practice. The regulation aimed at controlling traditional medical practitioners who had been practicing medicine without any qualification as a physician. The regulation was very brief, consisting of only seven articles. A newly revised regulation appeared in 1913 when Korea was under the occupation of Japan. The Japanese Government-General enacted a series of regulations about medical personnel, including dentists and traditional medical practitioners. This heralds its full-scale engagement in medical affairs in Korea. Unlike the case of European countries where medical license was obtained after a long struggle with other practitioners, in Korea, medical license was given to doctors too easily from the state. And this experience played a very important role in the formation of identity of Korean doctors.