The effect of tongue reduction for preventing adverse effects in patients undergoing class III orthognathic surgery: a three-dimensional comparative analysis.

OBJECTIVES: This study aims to evaluate the potential benefits of combining tongue reduction with mandibular setback surgery in patients undergoing class III orthognathic surgery. Specifically, we investigated whether this combined approach reduced the risk of surgical relapse, condylar resorption, and airway space reduction by mitigating tongue pressure on the mandible. MATERIAL AND METHODS: The study retrospectively enrolled patients who had undergone bilateral sagittal split ramus osteotomy (BSSRO) with at least 5 mm of setback and met the criteria of a body mass index > 20 kg/m2 and tongue volume > 100 mm3. The study included 20 patients with 10 in the tongue reduction group (TR, n = 10) and 10 in the BSSRO only group (SO, n = 10). RESULTS: The volumetric changes of the total airway space were significantly different between the TR and SO groups (p = 0.028). However, no significant differences were observed in the condylar resorption and postoperative relapse between the groups (p = 0.927 and 0.913, respectively). The difference between the resorption of the anterior and posterior segments of the condyle was also statistically insignificant (p = 0.826). Postoperative counterclockwise rotation of the proximal segment only demonstrated a significant correlation with postoperative relapse (p = 0.048). CONCLUSIONS: The reduction in tongue volume demonstrated a preventive effect on the reduction of the airway space after mandibular setback, although it did not yield statistical significance concerning surgical relapse and condylar volume. The counterclockwise rotation of the proximal segment might be responsible for the forward displacement of the distal segment and postoperative relapse. However, the clinical implications of this finding should be interpreted with caution owing to the limited sample size CLINICAL RELEVANCE: Tongue reduction could potentially serve as a preventive measure in preserving the airway space and might be beneficial in mitigating the risk of obstructive sleep apnea in patients with class III deformity.

The Application of Lag Screws and Digital Positioning Guide in Treating Sagittal Split Fracture of the Mandible.

Sagittal mandibular fractures are challenging to manage using traditional open reduction and internal fixation techniques due to the difficulty in manually reducing mandibular fragments and performing osteosynthesis on the lingual side. In addition, there is a risk of damaging dental roots with screws during fixation. In this case, the authors employed the lag screw technique combined with digitally guided surgery to effectively perform osteosynthesis on the fragments and avoid iatrogenic tooth and nerve injury.

Effect of agents affecting bone homeostasis on short- and long-term implant failure.

OBJECTIVES: To review the current evidence on the relationship between agents that affect bone homeostasis and dental implant failures. MATERIALS AND METHODS: Electronic searches for bisphosphonates, denosumab, methotrexate, corticosteroids, romosozumab, sunitinib, and bevacizumab were performed using PubMed, MEDLINE (OVID), EMBASE (OVID), Cochrane Central Register of Controlled Trials (Cochrane Library), Cochrane Oral Health Group Trials Register (Cochrane Library) and Web of Science (Thomson Reuters). Manual searches were also conducted to complement the digital searches for recent issues. RESULTS: Previous publications suggested that bisphosphonates do not compromise the survival of dental implants. However, one study documented an increased risk of implant failure in patients who had received high-dose of intravenous bisphosphonate therapy after implant rehabilitation. There has been an issue of MRONJ around implants in patients who have successfully received implant therapy before and after antiresorptive therapy, leading to late implant failure. Despite evidence on the detrimental effects of denosumab, methotrexate and corticosteroids on bone metabolism, their role in implant survival is not conclusive. CONCLUSIONS: At present, there is insufficient evidence to establish a potential connection between agents that affects bone homeostasis and implant failure. However, some studies have reported negative results for implant therapy. In addition, implant-related sequestration in patients who received anti-resorptive therapy, despite of successful osseointegration, is also noticeable. Although limited studies are available at present, clinicians should still carefully consider the potential hazards and take appropriate precautions to minimize the risks associated with the medications and implant therapy.

Group 3 ITI Consensus Report: Materials and antiresorptive drug-associated outcomes in implant dentistry.

OBJECTIVES: The aim of Working Group 3 was to address the influence of both material- and anti-resorptive drug- related factors on clinical and biological outcomes and complications in implant dentistry. Focused questions were addressed on (a) implant materials other than titanium (alloy)s, (b) transmucosal abutment materials and (c) medications affecting bone metabolism were addressed. MATERIALS AND METHODS: Three systematic reviews formed the basis for discussion in Group 3. Consensus statements and clinical recommendations were formulated by group consensus based on the findings of the systematic reviews. Patient perspectives and recommendations for future research were also conveyed. These were then presented and accepted following further discussion and modifications as required by the plenary. RESULTS: Zirconia is a valid alternative to titanium as material for implant and transmucosal components, allowing soft and hard tissue integration with clinical outcomes-identified by implant survival, marginal bone loss and peri-implant probing depths-up to 5-years comparable to titatnium. However, most of the evidence for zirconia implants is based on 1-piece implants limiting the indication range. Furthermore, based on expert opinion, zirconia transmucosal components might be preferred in the esthetic zone. In patients receiving low-dose bisphosphonate therapy, the rate of early implant failure is not increased, while the long-term effects remain poorly studied. Although it has not been sufficiently addressed, similar outcomes can be expected with low-dose denosumab. A drug holiday is not recommended when considering implant placement in patients treated with low-dose ARD. However, the specific therapeutic window, the cumulative dose and the administration time should be considered. Access to peri-implant supportive care is mandatory to prevent peri-implantitis-related medication-related osteonecrosis of the jaw (MRONJ) or implant-related sequestra (IRS). In patients receiving low-dose anti-resorptive drugs (ARD) therapy, the risk of complications related to implant placement is high, and implant procedures in this specific population should be strictly treated in a comprehensive multidisciplinary center. Finally, healthy dental implants should not be removed before low or high-dose ARD. CONCLUSIONS: Zirconia implants can be an alternative to titanium implants in selected indications. However, the current state of evidence remains limited, especially for 2-piece implant designs. Administration of low-dose ARD did not show any negative impact on early implant outcomes, but careful follow-up and supportive care is recommended in order to prevent peri-implant MRONJ and IRS. Implant placement in high-dose patients must be strictly considered in a comprehensive multidisciplinary center.

EMD-liquid contributes to tissue thickness gain in soft tissue augmentation using a collagen matrix.

OBJECTIVES: To investigate the function of enamel matrix derivative (EMD)-liquid compared to EMD-gel (original Emdogain® with polyglycolic acid-carrier) in inducing soft tissue regeneration using a rat dorsal model. MATERIAL AND METHODS: Four subcutaneous pouches were created through dorsal skin incisions in 18 female Wistar rats and randomly allocated to the following groups: (1) sterile saline + non-crosslinked collagen matrix (CM), (2) EMD-gel + CM, and (3) EMD-liquid + CM. After 2 and 4 weeks of healing, the specimens were harvested and stained with Goldner's trichrome, hematoxylin and eosin, and were immunohistochemically stained with an anti-CD31 antibody. RESULTS: The EMD-liquid group showed the thickest connective tissue compared to the other groups, with statistical significance both at 2 (p < 0.001) and 4 weeks (p = 0.011 and 0.023, respectively). The number of multinucleated giant cells was not significantly different among the groups for both periods. Moreover, there was a tendency to have more blood vessels over a longer period, and the highest number of blood vessels was observed in the EMD-liquid group at 4 weeks (p = 0.009 and 0036, respectively). CONCLUSION: EMD-liquid-treated CM is advantageous compared to using CM alone or EMD-gel-treated CM, owing to the histomorphometric results that show significantly increased soft tissue thickness and number of blood vessels when EMD-liquid was pre-primed to CM. CLINICAL RELEVANCE: EMD with a liquid carrier may be an appropriate biologic supplement to provide cell-inducing properties to the CM scaffold and is clinically more beneficial for phenotype modification therapy than CM only and EMD-gel-treated CM.

Shift work sleep disorder is closely associated with an increased risk for periodontal disease.

AIM: This study aimed to investigate the association between work patterns and periodontal disease. MATERIALS AND METHODS: Data were collected from the Korea National Health and Nutrition Examination Survey between 2007 and 2012, and data from 22,508 subjects aged ≥19 years were included. An individual's work pattern was classified as either daytime or shift work. Sleep duration was categorized into three ranges: ≤5, 6-8, and ≥9 h/day. A multivariate logistic regression model was used to determine the adjusted odds ratio (OR) for CPI (Community Periodontal Index) ≥3. The CONTRAST statement was used to show the interaction effect of work patterns and sleep duration. RESULTS: The adjusted OR of shift work was 2.168 (CI: 1.929-2.438, p < .0001). Participants who sleep ≤5 or ≥9 h/day showed ORs 0.735 and 0.663, respectively (p = .0181). Interaction effect analysis revealed that the work pattern had a strong influence on periodontal condition when combined with the sleep amount. Shift workers with ≤5 or ≥ 9 h of sleep showed significantly increased ORs for CPI ≥3 (2.1406 and 2.3251, respectively, p < .0001). The ORs for daytime workers were comparable to the original values (≤5: 0.7348, p = .0292; ≥9: 0.6633, p = .0428). CONCLUSION: Altered sleep patterns caused by shift work have more influence on periodontal disease than sleep duration.

Effect of enamel matrix derivative liquid combined with synthetic bone substitute on bone regeneration in a rabbit calvarial model.

OBJECTIVES: This study aimed to verify the effectiveness of EMD-liquid in combination with a synthetic bone substitute in a rabbit calvarial model. MATERIAL AND METHODS: Four 7-mm outer diameter circular slits were created in the calvaria of 10 New Zealand white rabbits, and polycarbonate cylinders were inserted into the slits. Two experimental groups were established: (1) EMD-liquid + bone substitute (Osteon III®; biphasic calcium phosphate (BCP), ß-TCP/HA = 40:60) and (2) saline + bone substitute (Osteon III®; BCP). The cylinders were filled with saturated graft materials and covered with polycarbonate caps. Micro-CT and histomorphometric evaluation were conducted. RESULTS: In the histomorphometric analysis, new bone formation was significantly higher in the bone substitute (BS) + EMD-liquid group than in the BS only group at both 5 and 10 weeks (p < 0.01). There were statistically significant differences in the material area between the bone substitute and bone substitute + EMD-liquid groups at only 5 weeks (p < 0.05). The BS + EMD-liquid group demonstrated reduced material area to a greater extent. In micro-CT analysis, the BS + EMD-liquid group (27.04 ± 8.06 at 5 weeks, 28.49 ± 9.22 at 10 weeks) showed a significantly higher percentage of mineralized tissue volume at both 5 and 10 weeks (p < 0.05) than the BS only group. CONCLUSION: EMD-liquid enhances new bone formation when combined with BCP bone substitute in an animal model. Moreover, the EMD-liquid + BS has significantly lesser material area than BS alone, indicating accelerated graft degradation. Further studies on types of graft materials are required to verify the effect of EMD-liquid and to optimize its regenerative potential. CLINICAL RELEVANCE: This study suggests that EMD-liquid may have beneficial effect on bone regeneration with synthetic bone substitute.

Axial Triangle of the Maxillary Sinus, and its Surgical Implication With the Position of Maxillary Sinus Septa During Sinus Floor Elevation: A CBCT Analysis.

The aim of this study was to measure the convexity of the lateral wall of the maxillary (Mx) sinus and identify the locational distribution of antral septa in relation to the zygomaticomaxillary buttress (ZMB), in order to suggest another anatomical consideration and surgical modification of sinus floor elevation procedures. This study was designed as a cross-sectional study, and a total of 134 patients and 161 sinuses containing edentulous alveolar ridges were analyzed. The angle between the anterior and lateral walls of the Mx sinus (lateral sinus angle [LSA]), and the angle between the midpalatal line and the anterior sinus wall (anterior sinus angle [ASA]) were measured. Mean LSAs and ASAs were 105.9° ± 9.86° and 58.4° ± 6.43°, respectively. No significant difference between left and right sides was found (LSA, P = .420; right = 105.5° ± 9.27°; left = 105.5° ± 9.27° and ASA, P = .564; right = 57.9° ± 6.80°; left = 58.8° ± 6.02°). The prevalence of septa was 37.3%, and it was most frequently noted in the second molar region (32.8%), followed by the first molar (20.9%), retromolar (16.4%), and second premolar regions (14.9%). Septa were most frequently located posterior to the ZMB (49.2%), while ZMB was mostly located in the first molar region (66.4%). Narrow LSAs may complicate the surgical approach to the posterior maxilla, especially when sinus elevation should be used in the second molar region. Considering the occasional presence of antral septa, membrane elevation may be complicated when a septum is encountered during the procedure. These results suggest that 3-dimensional examination of the convexity of the Mx sinus should be performed preoperatively to choose proper surgical techniques and minimize surgical complications.

Biofunctionalization of porcine-derived collagen matrix using enamel matrix derivative and platelet-rich fibrin: influence on mature endothelial cell characteristics in vitro.

OBJECTIVES: The present study evaluated the effect of an enamel matrix derivative (EMD) and platelet-rich fibrin (PRF)-modified porcine-derived collagen matrix (PDCM) on human umbilical vein endothelial cells (HUVEC) in vitro. MATERIALS AND METHODS: PDCM (mucoderm®) was prepared to 6 mm (±0.1 mm) diameter discs. PDCM samples were incubated with either EMD, PRF, or control solutions for 100 min at 4 °C before the experiments. Cell-inducing properties of test materials on HUVEC cells were tested with cell proliferation assays (MTT, PrestoBlue®), a cytotoxicity assay (ToxiLight®), a Boyden chamber migration assay, and a cell attachment assay. Scanning electron microscopy (SEM) imaging was performed to determine the surface and the architecture of the modified matrices. RESULTS: Cell proliferation was elevated in the EMD and PRF groups compared with control (p each ≤0.046). PRF modification increased HUVEC migration ability by 8-fold compared with both control and EMD groups (p each <0.001). Both treatments significantly promoted the cell attachment of HUVEC to PDCM, as assessed by direct cell counts on the matrices (p each <0.001). CONCLUSIONS: HUVEC cell characteristics were overall improved by EMD- and PRF- modified PDCM. Adsorbed bioactive molecules to the PDCM surface may have contributed to a more preferable environment to surrounding cells. CLINICAL RELEVANCE: The results may give evidence that PDCM modification with EMD or PRF, respectively, might be a useful approach to improve clinical outcomes, to prevent inflammatory reactions and wound-healing disturbances, and to expand the clinical application area of PDCM.

Effects of an oral bisphosphonate and three intravenous bisphosphonates on several cell types in vitro.

OBJECTIVE: To analyze the influence of an oral bisphosphonate and compare the potency to intravenous bisphosphonates on various cell types as regards the rarity of bisphosphonate-associated osteonecrosis of the jaw (BP-ONJ) caused by oral bisphosphonate. MATERIALS AND METHODS: A viability assay (MTT), a migration assay (Boyden chamber), and an apoptosis assay (Caspase-Glo® 3/7) were performed to analyze the effect of bisphosphonates on human fibroblasts, umbilical vein endothelial cells (HUVEC), and osteoblasts. RESULTS: Alendronate and intravenous bisphosphonates suppressed cell viability and migration, and induced apoptosis in all tested cell types. Alendronate had a greater impact than ibandronate on the characteristics in fibroblasts and osteoblasts but not as strong as zoledronate. CONCLUSIONS: The incidence of BP-ONJ in oral bisphosphonate treatment is reported to be much lower than that in intravenous bisphosphonates. However, the influences of alendronate on human cells were at least as strong as ibandronate, although it was lower than zoledronate. CLINICAL RELEVANCE: Alendronate showed strong enough effects to suppress human somatic cells and was comparable to certain intravenous bisphosphonates in potency. This study suggests that the lower incidence of BP-ONJ in alendronate treatment is not originated by its potency, but might be due to the low bioavailability of alendronate, lower dosing on a daily basis, and having no additional therapies.

A 10-Year Cone Beam Computerized Tomography Observation of the Buccal Bony Wall of an Immediately Placed Implant at the Anterior Maxilla: A Case Report.

Since the introduction of immediate implant placements, the buccal bony wall has been a major consideration for success due to its correlation with soft tissue contour and color. This report presents the stability of the buccal wall thickness of an immediately placed implant at the anterior maxilla over 10 years. Although the width of the buccal wall decreased at the 2-year post-op follow-up, it remained stable afterward according to cone beam computerized tomography (CBCT) scans. Hence, this report suggests that ensuring adequate bony wall thickness with bone augmentation and fixture position may promise the longevity of the buccal bony wall and surrounding soft tissue in an immediate implant placement.

"It All Started from Worms": Korea-Japan Parasite Control Cooperation and Asian Network, 1960s - 1980s.

The Korea Association of Health Promotion and Japanese Organization for International Cooperation in Family Planning (JOICFP), and Taiwan's Chinese Foundation of Health all originated from parasite control organizations. Currently these organizations hold no apparent relations to parasite control activities. However, many of the senior leaderships of these organizations including presidents, have parasitology as their background. Kunii Chojiro (the founder of Japan Association of Parasite Control (JAPC) and JOICFP) explained it as "it all started from worms." In 1949, Kunii Chojiro established JAPC after personally experienced intestinal parasite infection. The JAPC people conducted mass examination and mass chemotherapy focusing on school children, which allowed them to have sustainable income. In 1965, the Korea Association of Parasite Eradication (KAPE) requested JAPC to assist Korea's parasite control activity. In 1968, when Korea-Japan cooperation for parasite control activity established, Japan's operating procedures were directly absorbed by KAPE. With support from JAPC and official development aid through Overseas Technical Cooperation Agency in Japan (now Japan International Cooperation Agency), Korea successfully controlled parasite infection. Post-war and cold-war geopolitics had a significant impact on Korea-Japan cooperation. In 1960s the president of KAPE, Chong-Chin Lee and Kunii Chojiro were well known figures in population control network. They did understand the importance of population control, but did not agree with the approaches taken by western population control experts. From their point of view, it had to be self-initiated, economically self sustainable grass-root activities rather than top-down activities, as experienced in their parasite control in Japan and Korea. This lead to a new Asian model named "Integrated Program". Together with their influence in population control network, Kunii and Lee manage to secure the fund from IPPF. Emergence of Integrated Program showed how collective experience of Asia, as well as overlap of networking formed 'Asian Model' of public health activities. Kunii and Lee shared the same agenda to enable people to have better life through public health measures. While they funneled money from global population control network, they were more interested in securing sustainability of the parasite control activities. This paper focuses on activities and experiences of Kunii Chojiro and Chong-Chin Lee to show interplay of Cold War geopolitics in Asia led to emergence of Asian network.

A retrospective study of osteomyelitis and osteonecrosis of the jaws and its etiologic implication of bisphosphonate in Asians.

OBJECTIVE: The objective of this study were to find the annual case trend of inflammatory jawbone diseases and to investigate the impact of medication-related osteonecrosis of the jaws (MRONJ). MATERIAL AND METHODS: A retrospective study of 372 patients diagnosed with inflammatory jawbone condition except for alveolar osteitis from 2007 to 2015 was initiated. History taking and investigation of etiologic factors MRONJ, osteoradionecrosis (ORN), odontogenic infection, foreign body, and trauma were investigated. A separate analysis showed the number of MRONJ cases in two age groups (under 70 years; 70 years and over) and serum C-terminal peptide (s-CTX) values that were found. RESULTS: The results showed that the number of MRONJ cases was significantly larger in the older age group (p < 0.05). Regarding gender and sites of lesions, MRONJ was significantly frequent in the female and the mandible (p < 0.05). The R 2 values for the regression analysis for MRONJ (R 2 = 0.9234) and odontogenic etiology (R 2 = 0.0427) signified linear increase in the number of MRONJ cases, whereas bone lesions due to traditional odontogenic etiology stayed stationary. CONCLUSION: The number of MRONJ has escalated, and most of the patients are elderly people. The current trend of inflammatory conditions of the jaw may have changed since the advent of MRONJ. CLINICAL RELEVANCE: Long-term bisphosphonate therapy became a major risk factor for the osteomyelitis and osteonecrosis of the jaws. Thorough medical history, taking would be essential and communication with prescribing physicians should be emphasized during the dental treatment planning.

Volume stability of hydroxyapatite and ß-tricalcium phosphate biphasic bone graft material in maxillary sinus floor elevation: a radiographic study using 3D cone beam computed tomography.

OBJECTIVES: The purpose of this study was to confirm volume stability of biphasic calcium phosphate (BCP) through the changes of grafted volume over the time by 3D CT analyzing software program. PATIENTS AND METHODS: Fifteen patients, 16 sinuses who were scheduled a staged implantation through sinus floor elevation (SFE)-lateral window technique from 2009 to 2011 were included in the study. Of the 15 patients, eight were male and seven were female (mean age 50.1). For sinus floor augmentation, BCP with local blood was packed loosely into the maxillary sinus and the grafted site was covered with a collagen membrane. For the evaluation of volume change, 3D CBCT scans were taken five times at pre-operatively (To), post-op 1 week (T1), 1 month (T2), 3 months (T3), and 6 months (T4). 3D image processing software (OnDemand3DTM software) was used for this study. The time sequential change was statistically evaluated. RESULT: 84.32% grafted BCP is maintained until post-op 6 month (T4), and the average volume loss is 207.7 mm(3) (about 0.21 cc). Statistically, a significant volume change (decreasing) was observed in three groups (T2-T1, T3-T2, T4-T3). CONCLUSION: Biphasic calcium phosphate, as a synthetic material, has high volume stability and is a predictable graft material for the successful SFE. Although some limitations of the 3D analyzing software program, it is a fast, simple, relatively accurate and promising approach to quantifying long-term changes in the grafted area.

A Social History of Ascariasis in the 1960s Korea : From a Norm to a Shameful Disease.

Until the 1950s, Ascaris was regarded as an essential part of life which controls every aspect of human physiology among Koreans. Therefore, Ascaris should not be removed from human body. Efforts from medical professionals and the Korean government officials who wished to push forward the parasite control program, had to constantly contest with this perception of Ascaris among ordinary Koreans. In 1966, the 'Parasitic Disease Prevention Act' was promulgated and 'the Korean Association for Parasite Eradication (KAPE)' established in Korea. From the 1970s, Korea mobilized 15 million people each year to achieve the eradication goal. Such mass mobilization could not be possible without public awareness on necessity of parasite eradication. Until the early 1960s, however, Korean people were not sympathetic to the needs of eradication of parasites, especially that of Ascaris. Then, what changed the social perception towards Ascaris during the 1960s? What contributing factors allowed the mass mobilization and public involvement for that campaign? Employing newspaper articles and periodicals, this paper analyzes how social perception on Ascariasis changed during the 1960s, when the 'Parasitic Disease Prevention Act' was established. During the 1960s, Ascariasis became a shameful disease for Koreans. A series of events made Ascariasis more visible and shameful to Koreans. First event happened with Korean miners who were dispatched to Germany in 1963. When the miners turned out to have been infected with intestinal parasites, they were prohibited from work at the mines by the authorities in Germany and quarantined for several weeks. This humiliating experience of Korean expatriate people having bodies swarmed with parasites became a national shame to Koreans. The parasite infected bodies of Korean workers were revealed to the World through German newspapers. Second event happened when a child died of intestinal obstruction due to Ascariasis. The doctor retrieved 1,063 Ascaris from the bowel of the 9 year-old girl, and the photo of the 1,063 worms was published in several newspapers. It was a shocking visualization of Ascariasis in Korean society. Through these visualizations of Ascariasis, the Korean society began to perceive Ascariasis as a shame of the nation as well as that of an individual.

High-durable AgNi nanomesh film for a transparent conducting electrode.

Uniform metal nanomesh structures are promising candidates that may replace of indium-tin oxide (ITO) in transparent conducting electrodes (TCEs). However, the durability of the uniform metal mesh has not yet been studied. For this reason, a comparative analysis of the durability of TCEs based on pure Ag and AgNi nanomesh, which are fabricated by using simple transfer printing, is performed. The AgNi nanomesh shows high long-term stability to oxidation, heat, and chemicals compared with that of pure Ag nanomesh. This is because of nickel in the AgNi nanomesh. Furthermore, the AgNi nanomesh shows strong adhesion to a transparent substrate and good stability after repeated bending.

Making of the "Pristine Vegetables": Soil-Transmitted Parasites and U.S. Military Procurement in Korea.

In the twenty-first century Korea, "Pristine Vegetables(청정채소)" refers to organic products grown without the use of pesticides and chemical fertilizers. However, the meaning of "Pristine" was radically different until 1970s. After the Korean War, the infection rate of intestinal parasite reached almost 100 percent in Korean population. Disruption in chemical fertilizers manufacturing pressured farmers to use night-soil, which was contaminated with parasite eggs, causing the vicious cycle of infection. At the same time, rapid urbanization increased the demands of fresh vegetables in the city, leading to a large amount of semi-urban agricultural practices. This was closely linked with the national economy; as most of Korean vegetable products were contaminated with parasites, they were deemed unsuitable for export. In 1957, US Army stationed in Seoul issued a guideline for producing local vegetables acceptable for US troop consumption. This gave rise to the concept of "Pristine Vegetables" that were free of any infectious materials. These practices continued well into the 1970s. Due to the lack of sewage treatment system, the waste of urban population provided necessary fertilizer for these farmers without much cost. In order to secure public health, the Korean government actively encouraged the use of chemical fertilizers, naming the vegetables "Pristine." This effort included the ban of night-soil in urban and semi-urban farms and the establishment of Pristine Vegetable Shops. However, the rapid decline of parasitic diseases in the population and the rising concerns of environmental pollutions reshaped Pristine Vegetables from chemical to organic in the 1980s. Thus, Pristine Vegetable in Korea during late twentieth century exemplifies rapid transformation of the urban environment, showing shifted concept of cleanness and contaminants among the public and policymakers, as well as acceptable risk of the urban environment in Korea.

Atomic Layer Etching Using a Novel Radical Generation Module.

To fabricate miniature semiconductors of 10 nm or less, various process technologies have reached their physical limits, and new process technologies for miniaturization are required. In the etching process, problems such as surface damage and profile distortion have been reported during etching using conventional plasma. Therefore, several studies have reported novel etching techniques such as atomic layer etching (ALE). In this study, a new type of adsorption module, called the radical generation module, was developed and applied in the ALE process. Using this module, the adsorption time could be reduced to 5 s. Moreover, the reproducibility of the process was verified and an etch per cycle of 0.11 nm/cycle was maintained as the process progressed up to 40 cycles.

A comparison study of vessel twisting by different microsurgical suture techniques in a chicken wing artery side to side bypass training model.

OBJECTIVE: Microvascular anastomosis, particularly side-to-side (STS) bypass, is a complex surgical procedure. While several suture techniques exist, none of them is superior to the others. We assessed the association between various STS bypass techniques and vessel twisting using chicken wing training models. METHODS: Three suture techniques were compared over an anterior wall suture procedure. The unidirectional continuous suture (UCS) group used a downward "right-to-left" continuous suture. The reverse continuous suture (RCS) group used a downward "left-to-right" continuous suture. The interrupted suture (IS) group used the standard interrupted suture. The number of samples in each of the three groups was 30 (n=90). We compared the incidence of vessel twisting and rotation angles across groups. RESULTS: Vessel twisting occurred in 96.7%, 56.7%, and 0% of the cases in the UCS, IS, and RCS groups, respectively. The incidence of vessel twisting differed significantly in all 3 groups (p<0.001), with an apparent trend (p=0.002). The mean rotation angles were 201˚±90.6˚, 102˚±107.6˚, and 0˚ in the UCS, IS, and RCS groups, respectively, which were significantly different (p<0.001). On excluding cases without twisting, the rotation angles of twisted vessels in the UCS and IS groups were 207.9˚±83.7˚ and 180˚±77.9˚, respectively, which yielded a significant difference between these groups (p<0.001). CONCLUSIONS: We found that the incidence and trend of vessel twisting differed significantly across suture techniques. The RCS technique may aid in preventing vessel twisting in the STS bypass procedure.

A Rare Case of Nontuberculous Mycobacterial Abscess Mimicking Brain Tumor in an Immunocompetent Patient.

Nontuberculous mycobacteria (NTM) is a type of bacteria that typically infects the pulmonary system, and NTM-central nervous system (CNS) infection, which occurs in the brain, is a very rare disease. A 64-year-old female patient presented with seizures as the main symptom and was found to have a mass of less than 1 cm in the right temporal lobe with accompanying edema. Although diseases such as tumor metastasis and parasitic cyst were suspected, the patient underwent a surgical resection, and NTM-CNS infection with abscess was diagnosed through biopsy. Antibiotic treatment was initiated after surgery, and the patient has been followed up without any significant symptoms. In this report, we review a rare case of NTM-CNS infection and discuss the understanding and treatment of this disease.