The North Equatorial Current and rapid intensification of super typhoons.

Super Typhoon Mangkhut, which traversed the North Equatorial Current (NEC; 8-17 °N) in the western North Pacific in 2018, was the most intense Category-5 tropical cyclone (TC) with the longest duration in history-3.5 days. Here we show that the combination of two factors-high ocean heat content (OHC) and increased stratification - makes the NEC region the most favored area for a rapid intensification (RI) of super typhoons, instead of the Eddy Rich Zone (17-25 °N), which was considered the most relevant for RI occurrence. The high OHC results from a northward deepening thermocline in geostrophic balance with the westward-flowing NEC. The stratification is derived from precipitation associated with the Inter-Tropical Convergence Zone in the summer peak typhoon season. These factors, which are increasingly significant over the past four decades, impede the TC-induced sea surface cooling, thus enhancing RI of TCs and simultaneously maintaining super typhoons over the NEC region.

Evaluating the effectiveness of online Continuing medical education during the COVID-19 pandemic.

OBJECTIVES: The study determined the effects of online continuing medical education (CME) on the clinical competency, performance, and patient outcomes of physicians and other healthcare professionals during the COVID-19 pandemic regarding the topics of COVID-19 and back pain. METHODS: Survey studies on six online CME activities were conducted from April 2020 to February 2021 at a South Korean hospital. Surveys were conducted immediately after and three months after the CME activity to measure the effectiveness of the CME activity regarding professional competence and performance, as well as patient outcomes. RESULTS: A total of 624 individuals participated in the six CME activities. Of the 2007 post-activity responses, a total of 1135 out of 1332 (85.21%) participants indicated that they were satisfied with the online education activities, and a total of 1752 out of 2007 (87.29%) participants responded that the content would influence their clinical practice. Upon a three-month follow-up, 477 out of 611 (78.07%) respondents indicated that they had made actual changes to their clinical practice. CONCLUSIONS: The online delivery method is effective for delivering CME. The results suggest that online CME ultimately influences physicians' clinical competency and performance, which leads to enforcing change in clinical practice.

Neurotherapeutic Potential of Cervus elaphus Sibericus on Axon Regeneration and Growth Cone Reformation after H2O2-Induced Injury in Rat Primary Cortical Neurons.

Cervus elaphus sibericus (CES), commonly known as deer antler, has been used as a medicinal herb because of its various pharmacological activities, including its anti-infective, anti-arthritic, anti-allergic, and anti-oxidative properties. However, the precise mechanisms by which CES functions as a potent anti-oxidative agent remain unknown; particularly, the effects of CES on cortical neurons and its neurobiological mechanism have not been examined. We used primary cortical neurons from the embryonic rat cerebral cortex and hydrogen peroxide to induce oxidative stress and damage in neurons. After post-treatment of CES at three concentrations (10, 50, and 200 µg/mL), the influence of CES on the neurobiological mechanism was assessed by immunocytochemistry, flow cytometry, and real-time PCR. CES effectively prevented neuronal death caused by hydrogen peroxide-induced damage by regulating oxidative signaling. In addition, CES significantly induced the expression of brain-derived neurotrophic factor and neurotrophin nerve growth factor, as well as regeneration-associated genes. We also observed newly processing elongated axons after CES treatment under oxidative conditions. In addition, filopodia tips generally do not form a retraction bulb, called swollen endings. Thus, CES shows therapeutic potential for treating neurological diseases by stimulating neuron repair and regeneration.

The neuroprotective effect of staurosporine on mouse retinal ganglion cells after optic nerve injury.

This study aimed to investigate the neuroprotective properity of staurosporine (STS) and identify the neuroprotective mechanism of staurosporine in mouse retina ganglion cell after optic nerve injured. Mice (C57BL/6) were anaesthetised with a mixture of 5 mg/kg xylazine hydrochloride and 40 mg/kg tiletamine/zolazepam (Zoletil®). Optic nerves of the mice were crushed (Templeton JP et al., 2012). With micro-forceps, the bulbar conjunctiva was grasped and retracted, rotating the globe nasally. The exposed optic nerve was grasped approximately 1-3 mm from the globe with Dumont #N7 cross-action forceps for 10 s. One day after crushing, intravitreal injections of STS (500 nM) were administered using a Narishige IM-300 air pressure regulator. For analysing the change in ganglion cell number, the mice were allowed to live for 30 days, after which they were killed and the ganglion cell survival was assessed. A significant and marked loss of fluorescent spots was found after 30 days, with fewer 4',6-diamidino-2-phenylindole (DAPI)-expressing retinal ganglion cells (RGCs) remaining in the injured and phosphate buffered saline (PBS)-injected group than those in non-injured PBS-injected controls. However, RGC cell numbers dramatically increased in the STS intravitreal injection group. Moreover, degradation of nerve fibre (NF) was markedly reduced in the STS injection group compared with the injured and PBS-injected group by inducing astrocyte expression of Bcl-2. Our data suggested that injection of STS into the vitreous may have a potential therapeutic effect in retinal diseases such as glaucoma.

Endoluminal Closure of Colon Perforation with Endoscopic Band Ligation: Technical Feasibility and Safety in an In Vivo Canine Model.

BACKGROUND/AIMS: Endoscopic band ligation (EBL) is an accepted method in the management of variceal bleeding; however, there is little evidence on the safety and feasibility of EBL for the closure of bowel perforation. In this study, we aimed to evaluate the technical feasibility and efficacy of EBL in iatrogenic colon perforation by using a canine model. METHODS: We established an iatrogenic colon perforation model by using seven beagle dogs. Longitudinal 1.5- to 1.7-cm colon perforations were created with a needle knife and an insulated-tip knife, and the perforation was subsequently closed with EBL. During a 2-week follow-up period, the animals were carefully monitored and then euthanized for pathologic examination. RESULTS: The EBL of iatrogenic colon perforations was successful in all dogs. The mean procedure time for EBL closure with one to three bands was 191.7 seconds, and there were no immediate complications. One animal was euthanized after 3 days because of peritonitis. There were no clinical and laboratory features of sepsis or peritonitis in the remaining six animals. On necropsy, we did not find any fecal peritonitis, pericolonic abscess formation, or transmural dehiscence at the perforation site. Histopathology demonstrated inflamed granulation tissue and scar lesions replaced by fibrosis. CONCLUSIONS: EBL might be a feasible and safe method for the management of iatrogenic colon perforations in an in vivo model.

Comparison of endoscopic band ligation and endoclip closure of colonic perforation: technical feasibility and efficacy in an ex vivo pig model.

BACKGROUND AND AIM: Recent reports have indicated several instances of successful treatment of bowel perforation by using endoscopic band ligation (EBL) when treatment with endoclipping is unsuccessful, but this salvage method has not been investigated in any prospective model. Herein we aimed to compare the technical feasibility and efficacy of EBL and endoclip use in intraluminal closure of colon perforation, in an ex vivo model. METHODS: Standardized colonic perforations were created using fresh porcine colon and subsequently closed by full-thickness interrupted sutures, endoclip (QuickClip2(TM)), or EBL. Each closure site was tested with compressed air by using a digital pressure monitor for evaluating leak pressure. RESULTS: No significant differences were noted between the endoclip and EBL in leak pressures. Mean (± SD) pressures for air leakage from the perforations closed using the different devices were as follows: normal colon samples, 52.0 ± 13.2 mmHg; perforations closed with hand-sewn sutures, 32.3 ± 8.3 mmHg; perforations closed with endoclipping, 53.5 ± 22.7 mmHg; and perforations closed with EBL, 50.4 ± 12.5 mmHg. Time taken for closure by EBL was significantly less than that for closure by endoclipping (3.2 ± 1.7 min vs 6.8 ± 1.3 min, P < 0.01). Further, the number of devices used to achieve complete closure in the EBL group was lower than that with endoclipping (1.6 ± 0.5 vs 3.7 ± 0.8, P < 0.01). CONCLUSION: Endoluminal closure of a 1.5-cm colon perforation with EBL decreased procedure time and was not inferior in leak pressure compared with endoclipping in this ex vivo porcine model.

Curvature analysis of femoral shaft in total knee arthroplasty patient and control group.

For some patients with joint illnesses such as rheumarthritis or varus deformity, the total knee arthroplasty (TKA) procedures are performed. However, when inserting metal cutting guide for the procedures, due to the femoral shaft bowing, complications such as the cortex of the femoral shaft damages or secondary fractures can be caused. If the central coordinate value of the femoral shaft is known, the metal cutting guide could be inserted into the anatomical center, so such complications can be prevented. In this study, CT images of femoral shafts of 10 individuals in the experiment group who are in need of receiving the total knee arthroplasty procedures and those of 10 individuals in the control group without illness in the femoral shaft have been utilized to locate the 3-dimensional coordinate values. Then, Matlab was utilized to identify the central coordinate value in order to obtain a graph reflecting the anatomical shapes as well as to acquire the 3-dimensional curvature values by section. As a result, the average curvature range of femoral shafts of the experiment group was determined to be 631.2 mm whereas the average curvature range of femoral shafts of the control group was determined to be 1430.4 mm. The statistical significant of the measured results was verified through ANOVA analysis. Based on these results, it was verified that the level of curvature of the femoral shaft of the experiment group was higher. If the anatomical central points are located and analyzed using this methodology, it would be helpful in performing orthopedic operations such as the total knee arthroplasty.

A study on the artifacts generated by dental materials in PET/CT image.

PET/CT system reduces the scanning time and provides an anatomical image because it realizes a CT-based attenuation corrected image without using an isotope, such as 68 Ge or 137Cs, in the attenuation correcting method due to the recent technological development. On the other hand, artifacts are generated in a CT image by dental materials, which affect the attenuation corrected PET image. Against this backdrop, this study performed a clinical experiment and a phantom experiment. The clinical experiment targeted 40 patients without oral disease, including 20 patients who had metal prosthesis in their tooth and 20 patients who had a dental implant in tooth. In the phantom experiment, a dental cast was used for a PET/CT scan after the metal prosthesis and the dental implant was inserted in the original dental phantom to make a dental cast. According to the study results, when the patients had metal prosthesis, standard uptake value (SUV) decreased by approximately 19.6% in the dark streak artifact region and increased by approximately 90.1% in the bright streak artifact region, compared with the artifact free region. In the phantom with metal prosthesis, the SUV decreased by approximately 18.1% in the dark streak artifact region and increased by 18.0% in the bright streak artifact region, compared to the artifact free region. When the patients with dental implant, the SUV decreased by approximately 19.1% in the dark streak artifact region and increased by 96.6% in the bright streak artifact region, compared with the artifact free region. In the phantom with dental implant, the SUV decreased by approximately 14.4% in the dark streak artifact region and increased by 7.0% in the bright streak artifact region, compared to the artifact free region. Therefore, by considering these results, we can improve the diagnostic accuracy in oral and maxillofacial cancer.

Discussion on the alteration of 18F-FDG uptake by the breast according to the menstrual cycle in PET imaging.

18F-FDG PET/CT is a useful modality for identifying high-glucose-consuming cells, such as cancer cells by the glucose metabolism of FDG. FDG is taken up by cancer and inflammatory cells but occasionally, there is some FDG uptake on normal tissues as a result of their individual physiological characteristics. In particular, in fertile females, unusual FDG uptake in the breast changes according to the stages in the menstrual cycle, which can adversely affect a diagnosis. Therefore, this study examined the change in breast FDG uptake in the menstrual cycle on 18F-FDG PET/CT. One hundred and sixty females (34 ± 3.5 years old), who had not undergone a gynecologic anamnesis and had a regular menstrual cycle over the previous 6 months, were examined from March 2011 to February 2012. The subjects were divided into the following 4 groups (each with 40 patients): flow phase, proliferative phase, ovulatory phase and secretory phase using Pregnancy Calculator 0.14 and history taking. Discovery STE (GE Healthcare, USA) was used as the PET/CT. The SUVs on the accumulated region on the breast were analyzed, and 3 nuclear medicine specialists performed a blind test. The SUVs on the breast were the flow phase (1.64 ± 0.25), proliferative phase (0.93 ± 0.28), ovulatory phase (1.66 ± 0.26) and secretory phase (1.77 ± 0.28). Higher uptake values were observed in the secretory, flow phase and ovulatory phase (p< 0.05). The accumulation of the breast was divided into the following 3 grades compared to the lung and liver by gross analysis: the breast uptake was equal to the lung (Grade I); between the lung and liver (Grade II); and equal to or greater than the liver (Grade III). These results showed a high uptake value in the secretory, flow phase and ovulatory phase (p <0.05). In fertile females, the FDG uptake of the breast showed changes according to the menstrual cycle, which can be used to improve the diagnosis of breast disease. Therefore, the false-negative findings of breast disease can be reduced by performing an examination at the appropriate period through history taking and considering the individual menstrual cycle.

Heart sounds analysis via esophageal stethoscope system in beagles.

Esophageal stethoscope is less invasive and easy to handling. And it gives a lot of information. The purpose of this study is to investigate the correlation of blood pressure and heart sound as measured by esophageal stethoscope. Four male beagles weighing 10 to 12 kg were selected as experimental subjects. After general anesthesia, the esophageal stethoscope was inserted. After connecting the microphone, the heart sounds were visualized and recorded through a self-developed equipment and program. The amplitudes of S1 and S2 were monitored real-time to examine changes as the blood pressure increased and decreased. The relationship between the ratios of S1 to S2 (S1/S2) and changes in blood pressure due to ephedrine was evaluated. The same experiment was performed with different concentration of isoflurane. From S1 and S2 in the inotropics experiment, a high correlation appeared with change in blood pressure in S1. The relationship between S1/S2 and change in blood pressure showed a positive correlation in each experimental subject. In the volatile anesthetics experiment, the heart sounds decreased as MAC increased. Heart sounds were analyzed successfully with the esophageal stethoscope through the self-developed program and equipment. A proportional change in heart sounds was confirmed when blood pressure was changed using inotropics or volatile anesthetics. The esophageal stethoscope can achieve the closest proximity to the heart to hear sounds in a non-invasive manner.

Medial prefrontal cortex is selectively involved in response selection using visual context in the background.

The exact roles of the medial prefrontal cortex (mPFC) in conditional choice behavior are unknown and a visual contextual response selection task was used for examining the issue. Inactivation of the mPFC severely disrupted performance in the task. mPFC inactivations, however, did not disrupt the capability of perceptual discrimination for visual stimuli. Normal response selection was also observed when nonvisual cues were used as conditional stimuli. The results strongly suggest that the mPFC is not necessarily involved in the inhibition of response or flexible response selection in general, but is rather critical when response selection is required conditionally using visual context in the background.