Search

As the prices of photovoltaics and wind turbines continue to decrease, more renewable electricity-generating capacity is installed globally. While this is considered an integral part of a sustainable energy future by many nations, it also poses a significant strain on current electricity grids due to the inherent output variability of renewable electricity. This work addresses the challenge of renewable electricity surplus (RES) utilization with target-scaling of centralized power-to-gas (PtG) hydrogen production. Using the Republic of Korea as a case study, due to its ambitious plan of 2030 green hydrogen production capacity of 0.97 million tons year

Background Escherichia coli have both the Embden–Meyerhof–Parnas pathway (EMPP) and Entner–Doudoroff pathway (EDP) for glucose breakdown, while the EDP primarily remains inactive for glucose metabolism. However, EDP is a more favorable route than EMPP for the production of certain products. Results EDP was activated by deleting the pfkAB genes in conjunction with subsequent adaptive laboratory evolution (ALE). The evolved strains acquired mutations in transcriptional regulatory genes for glycolytic process (crp, galR, and gntR) and in glycolysis-related genes (gnd, ptsG, and talB). The genotypic, transcriptomic and phenotypic analyses of those mutations deepen our understanding of their beneficial effects on cellulosic biomass bio-conversion. On top of these scientific understandings, we further engineered the strain to produce higher level of lycopene and 3-hydroxypropionic acid. Conclusions These results indicate that the E. coli strain has innate capability to use EDP in lieu of EMPP for glucose metabolism, and this versatility can be harnessed to further engineer E. coli for specific biotechnological applications.

There have been no reports regarding nystagmus observed immediately after the end of an acute vertiginous attack in patients with Meniere’s disease. The aim of this study was to demonstrate positional direction-changing nystagmus in patients with Meniere’s disease, and to discuss the mechanism that underlies this nystagmus. Video-nystagmography was recorded in two patients with definite Meniere’s disease, who showed positional direction-changing nystagmus during the period immediately after a vertigo attack. In one patient, video-nystagmographic recording was conducted 5 h after an episode of vertigo attack, and it showed very weak, persistent positional geotropic direction-changing nystagmus. In the other patient, video-nystagmographic recording was conducted 23 h after an episode of vertigo attack, and it showed very weak, persistent positional apogeotropic direction-changing nystagmus. Our patients exhibited very weak, persistent positional direction-changing nystagmus, which was geotropic in one and apogeotropic in the other. This type of positional nystagmus has been reported in other inner ear disorders and it cannot be clearly explained by typical benign paroxysmal positional vertigo. The change in chemical composition and/or electrolyte concentration of the inner ear fluid, although still unclear, may underlie the production of this characteristic nystagmus in these patients.

Hybrid catalysts consisting of metal nanoparticles on a metal oxide support have emerged as a new class of catalysts that can improve various electrocatalytic reactions, but the origin of the improved performance is still unclear. Here we demonstrate that rationally designed hybrid catalysts through the in situ exsolution process of metallic nanoparticles on a B-site Ni-substituted lead ruthenate pyrochlore oxide improve both oxygen evolution reaction and hydrogen evolution reaction activity. A combination of operando X-ray absorption spectroscopy measurements and density functional theory calculations reveals that the generated oxygen and cation vacancies in the pyrochlore oxide support during the in situ exsolution process can decrease the charge-transfer energy, thereby facilitating charge transfer between exsolved metal nanoparticles–oxide support as well as hybrid catalyst–electrolyte. These findings establish a structure–property relationship of complicated hybrid catalysts for efficient water splitting, suggesting a new strategy in designing various hybrid catalysts for other electrochemical reactions.

The degradation of amorphous cobalt phosphides (CoPx) as an electrocatalyst for the hydrogen evolution reaction (HER) is studied in the discontinuous operation of alkaline water electrolysis cells (AWEs). Although amorphous CoPx shows a 100-fold enhancement in HER activity over nickel, the kinetic current for the HER is decreased after discontinuous operation. Under the off condition, the cathode potential of the AWE increases close to the equilibrium potential for CoPx oxidation to Co, Co(OH)2, CoOx, and CoPxOy. The irreversible oxide and hydroxide formation induces weaker interactions between Co and P, and thus the degradation of kinetics over CoPx, negatively affecting the HER even though a cathodic current is applied for recovery. A cathodic protection method is devised to mitigate the degradation of CoPx by shifting the electrode potential below the equilibrium potential of Co(OH)2. Mn is chosen as a sacrificial species, and it slows the rate of electrode degradation by negative polarization of the electrode. The results show that the co-deposition of even a small amount of Mn onto the CoPx electrode could limit the loss of HER activity during repeated discontinuous operation of the AWEs. Furthermore, in situ X-ray absorption near edge structure analysis confirms that the CoPx with co-deposited Mn does show the effect on holding the phase of CoPx during discontinuous operation.

Telmisartan, rosuvastatin and ezetimibe are commonly recommended as combination therapies. However, the pharmacokinetic (PK) interaction among these therapeutic drugs has not been clearly reported. The objective of this study was to investigate possible interactions between telmisartan monotherapy and a fixed-dose combination (FDC) of rosuvastatin/ezetimibe. A randomized, open-label, multiple oral dose, three-treatment, three-period, six-sequence crossover study was conducted in healthy male volunteers. Monotherapy and cotherapy with telmisartan (80 mg) or a FDC of rosuvastatin and ezetimibe (20/10 mg) were compared after once-daily treatment for 7 days. The PK profiles for telmisartan, rosuvastatin, total ezetimibe (ezetimibe + exetimibe glucuronide) and ezetimibe were evaluated up to 48 h after the last dose. There was a 14-day washout period between each treatment. The geometric mean ratios (GMRs) and 90% confidence intervals (CIs) for the peak plasma concentration at steady state (Cmax,ss) and area under the plasma concentration-time curve during the dosing interval at steady state (AUCτ,ss) were 1.258 (1.072–1.475) (P = 0.020) and 1.264 (1.167–1.370) (P

Optical intensity interferometry, developed in the 1950s, is a simple and inexpensive method for achieving angular resolutions on microarcsecond scales. Its low sensitivity has limited intensity interferometric observations to bright stars so far. Substantial improvements are possible by using avalanche photodiodes (APDs) as light detectors. Several recent experiments used APDs in single-photon detection mode; however, these either provide low electronic bandwidths (few MHz) or require very narrow optical bandpasses. We present here the results of laboratory measurements with a prototype astronomical intensity interferometer using two APDs observing an artificial star in continuous (‘linear’) detection mode with an electronic bandwidth of 100 MHz. We find a photon–photon correlation of about 10−6, as expected from the ratio of the coherence times of the light source and the detectors. In a configuration where both detectors are on the optical axis (zero baseline), we achieve a signal-to-noise ratio of ∼2700 after 10 min of integration. When measuring the correlation as a function of baseline, we find a Gaussian correlation profile with a standard deviation corresponding to an angular half-width of the artificial star of 0.55 arcsec, in agreement with the estimate by the manufacturer. Our results demonstrate the possibility to construct large astronomical intensity interferometers using linear-mode APDs.

As the second year of the COVID-19 pandemic begins, it remains clear that a massive increase in the ability to test for SARS-CoV-2 infections in a myriad of settings is critical to controlling the pandemic and to preparing for future outbreaks. The current gold standard for molecular diagnostics is the polymerase chain reaction (PCR), but the extraordinary and unmet demand for testing in a variety of environments means that both complementary and supplementary testing solutions are still needed. This review highlights the role that loop-mediated isothermal amplification (LAMP) has had in filling this global testing need, providing a faster and easier means of testing, and what it can do for future applications, pathogens, and the preparation for future outbreaks. This review describes the current state of the art for research of LAMP-based SARS-CoV-2 testing, as well as its implications for other pathogens and testing. The authors represent the global LAMP (gLAMP) Consortium, an international research collective, which has regularly met to share their experiences on LAMP deployment and best practices; sections are devoted to all aspects of LAMP testing, including preanalytic sample processing, target amplification, and amplicon detection, then the hardware and software required for deployment are discussed, and finally, a summary of the current regulatory landscape is provided. Included as well are a series of first-person accounts of LAMP method development and deployment. The final discussion section provides the reader with a distillation of the most validated testing methods and their paths to implementation. This review also aims to provide practical information and insight for a range of audiences: for a research audience, to help accelerate research through sharing of best practices; for an implementation audience, to help get testing up and running quickly; and for a public health, clinical, and policy audience, to help convey the breadth of the effect that LAMP methods have to offer.

Purpose: This exploratory study aims to identify the influence of clinical practice belonging, satisfaction with major, and work values on the level of career identity among nursing students.Methods: The subjects of this study are 251 senior students from three nursing departments located in a metropolitan city. Using SPSS 22.0, the study uses technical statistics, t-test, One-way ANOVA, correlation, and multiple regression analysis.Results: The average scores for clinical practice belonging, satisfaction with major, and work values were 3.61, 3.87, and 3.70 out of 5.00, respectively, and 2.85 out of 4.00 for career identity. The factors affecting students' career identity were clinical practice belonging, aptitude, satisfaction with clinical practice, satisfaction with major, indoor work, service and employment at hospitals with 40 percent being explained by these variables.Conclusion: Through this study we found that clinical practice belonging has the greatest impact on career identity. In order to enhance clinical practice belonging, universities and clinical institutions need to develop new programs and curricula.

The presence of dizziness has been reported as a negative prognostic factor for recovery of facial palsy in Ramsay Hunt syndrome (RHS). The aim of this study was to investigate the incidence and patterns of nystagmus in RHS patients without dizziness, and discuss possible mechanisms. We also compared the severity and prognosis of facial palsy between RHS patients with and without dizziness. From January 2014 to January 2019, 36 patients diagnosed with RHS (27 with dizziness and 9 without dizziness) were included. Patterns of nystagmus were examined and categorized using video-nystagmography. House-Brackmann(HB) grade of facial palsy was compared between RHS patients with and without dizziness. Not only RHS patients with dizziness exhibited nystagmus in most cases (96%, 26 of 27) but also as many as 67% (6 of 9) of RHS patients without dizziness exhibited nystagmus, though the intensity was remarkably weak. In both groups of RHS with and without dizziness, direction-fixed nystagmus and direction-changing positional nystagmus were observed. Initial HB grade and recovery of facial palsy after treatment were not significantly different between RHS with and without dizziness. Various patterns of nystagmus including direction-fixed and positional direction-changing nystagmus were observed in RHS patients, and inflammation of the vestibular nerve and inner ear end organs may be responsible for the production of nystagmus in these patients. The results support that the evaluation of vestibular function may be necessary even in RHS patients who do not complain of dizziness or vertigo.

In terms of diagnosis, a painless isolated mass lesion around the mastoid area is rarely encountered in general practice. In the present study, we report two cases of painless benign mastoid tumors located in the postauricular region. The first patient visited our department with a painless progressing mass lesion behind the right ear, which was later revealed as an intramuscular lipoma in the mastoid origin site of the sternocleidomastoid muscle. The second patient similarly presented to our department with a chief complaint of a painless, palpable mass in the mastoid region. Biopsy results confirmed the diagnosis of an osteoma. In both cases, the tumor was surgically removed by a postauricular approach. Although osteoma and lipoma are benign tumors rarely involved in the mastoid area, presenting without symptoms, it is recommended of complete excision, especially in cases with symptoms or cosmetic deformity.

Objectives Considering that otolith particles pass through the canal until attaching to the cupula in the canal-side horizontal semicircular canal (HSCC) cupulolithiasis, comorbidity of HSCC canalolithiasis and cupulolithiasis may occur. We aimed to investigate the incidence of comorbidity of cupulolithiasis in patients with HSCC canalolithiasis and to improve treatment efficacy. Study design Retrospective study. Setting Tertiary referral academic center. Patients Ninety-seven consecutive patients with HSCC canalolithiasis between March 2017 and March 2019 were included. Main outcome measures Coexistence of HSCC cupulolithiasis was hierarchically investigated. 1) Spontaneous reversal of initial nystagmus is observed bilaterally in a head-roll test (HRT), 2) nystagmus is in the same direction at each of the three times the supine position was tested, and 3) both bowing and leaning nystagmus with opposite direction are observed. Results Of 97 patients with HSCC canalolithiasis, 2 patients (2%) had comorbid HSCC cupulolithiasis. Conclusions Although coexistence of HSCC canalolithiasis and cupulolithiasis should be considered when spontaneous reversal of nystagmus direction is observed without position change during a HRT, the incidence of coexistence is very low. However, canalith repositioning maneuvers for both canalolithiasis and cupulolithiasis should be performed in cases with comorbidity.

The combined operation of optokinetic reflex (OKR) and vestibular-ocular reflex (VOR) is essential for image stability during self-motion. Retinal slip signals, which provide neural substrate for OKR and VOR plasticity, are delivered to the inferior olive. Although it has been assumed that the neural circuitry and mechanisms underlying OKR and VOR plasticity are shared, differential role of the inferior olive in the plasticity of OKR and VOR has not been clearly established. To investigate the differential effect of inferior olive lesion on OKR and VOR plasticity, we examined the change of OKR and VOR gains after gain-up and gain-down VOR training. The results demonstrated that inferior olive-lesion differentially affected cerebellum-dependent motor learning. In control mice, OKR gain increased after both gain-up and gain-down VOR training, and VOR gain increased after gain-up VOR training and decreased after gain-down VOR training. In inferior olive-lesioned mice, OKR gain decreased after both gain-up and gain-down VOR training, and while VOR gain did not significantly change after gain-up VOR training, VOR gain decreased after gain-down VOR training. We suggest that multiple mechanisms of plasticity are differentially involved in VOR and OKR adaptation, and gain-up and gain-down VOR learning rely on different plasticity mechanisms.

Single-crystalline CoFe alloy nanoparticles encapsulated in nitrogen-doped carbon nanotubes (CoFe@N–C) were synthesized through a simple heat-treatment in an N2 environment. CoFe@N–C effectively catalyzed the overall water splitting in alkaline media. Specifically, the as-synthesized CoFe@N–C exhibited excellent activity towards the oxygen evolution reaction (OER) with a low overpotential of 292 mV at 10 mA cm−2 and the hydrogen evolution reaction (HER) with a low overpotential of 110 mV at 10 mA cm−2. The good electrocatalytic properties may be attributed to the synergistic electronic coupling between single-crystalline CoFe and highly conductive N-doped CNTs and the enrichment of active sites. Additionally, CoFe@N–C showed excellent stability and durability with no observable deviation in the overpotential for the OER and HER after 1000 cycles of cyclic voltammetry (CV).

Rationale: Vestibular paroxysmia (VP) is characterized by spontaneous, recurrent, short, paroxysmal attacks of vertigo with or without tinnitus. Patient concerns: We report a case of paroxysmal recurrent vertigo accompanying clicking tinnitus on the left side in a 61-year-old patient. He had undergone microvascular decompression to treat the left-side hemifacial spasm 6 years prior. The patient first developed vertigo attacks about 3 years after microvascular decompression, and the attacks increased in frequency over the last 4 months. Video-nystagmography revealed a background right-beating nystagmus which was reversed every 55 seconds, to left-beating nystagmus for 17 seconds. Diagnosis: Brain magnetic resonance imaging and angiography demonstrated a compression of the cisternal segment of the left vestibulocochlear nerve between the tortuous right vertebral artery and the posterior wall of the left porus acusticus internus. Interventions and outcomes: Under the diagnosis of VP, 300 mg oxcarbazepine was administered daily, which relieved the symptoms dramatically. Lesson: The neurovascular cross-compression of the vestibulocochlear nerve by the contralateral vertebral artery tortuosity can cause VP. Periodic paroxysms of right-beating nystagmus accompanying the left-side tinnitus during vertigo attacks in our patient can be explained by secondary central hyperactivity in both vestibular and cochlear nuclei following long-standing neurovascular cross-compression.

Powerful sunlight, a high water temperature, and stagnation in the water flow induce eutrophication in rivers and lakes, which destroys the aquatic ecosystem and threatens the downstream water supply systems. Accordingly, it is very important to perform real-time measurements of nutrients that induce algal growth, especially total phosphorus, to preserve and manage the aquatic ecosystem. To conduct quantitative analysis of the total phosphorus in the aquatic ecosystem, it is essential to perform a pretreatment process and quickly separate the phosphorus, combined with organic and inorganic materials, into a phosphate. In this study, the sandblasting process was used for the physical etching of the wafer, and photocatalytic materials were deposited on the surface with various roughness in order to improve the photocatalytic reaction surface and efficiency. The photocatalytic reaction was applied to combine the pretreated sample with the coloring agent for color development, and the absorbance of the colored sample was analyzed quantitatively to compare and evaluate the characteristics, followed by the surface increase in the photocatalytic materials. In addition, the pretreatment and measurement parts were materialized in a single chip to produce a small and light total phosphorus analysis sensor.

The most common symptoms of tumours involving the cerebellopontine angle (CPA) are unilateral sensorineural hearing loss, dizziness, and asymmetric tinnitus. While the clinical manifestations have been well documented in previous studies, the nystagmus findings in these patients have not been thoroughly investigated yet. This study aimed to investigate the incidence of direction-changing spontaneous nystagmus in patients with CPA tumours, evaluate their radiologic characteristics, and gain insight into the mechanisms underlying nystagmus. Direction-changing spontaneous nystagmus was observed in 6 out of 83 patients (7%) with CPA tumours during the 7-year period. Temporal bone magnetic resonance imaging findings revealed the presence of an intrameatal mass in CPA tumours in all six patients with direction-changing spontaneous nystagmus. Vestibular schwannomas were confined within the internal auditory meatus in four patients, and petroclival meningiomas extended into the internal auditory meatus in two patients. The mechanism of direction-changing spontaneous nystagmus may be explained as paroxysmal secondary central hyperactivity in the vestibular nucleus due to the long-standing pressure effect in the vestibular nerve by tumours, or by ephaptic discharges in the vestibular nerve.

Because the density of air is lower than the effusion, air bubbles can be passively moved by a head position change, causing a bubbling sound in the affected ear.

Ceruminous glands are located in the skin of the cartilaginous portion of the external auditory canal, and ceruminous gland adenoma originating from the middle ear mucosa is extremely rare. We report a case of middle ear ceruminous gland adenoma which caused long-standing otomastoiditis and mixed hearing loss with a large air-bone gap by obstructing the bony Eustachian tube. We discuss the clinical characteristics and histologic features of the present case.

Alkaline diaphragm water electrolysis (ADWE) devices have undergone widespread commercialization for about a century to date. Their high resistance relative to polymer electrolyte cells has motivated the employment of ion exchange membranes. However, recent advancements in the zero-gap configuration, in which porous electrodes are in contact with the porous ZrO2/polysulfone diaphragm, hold promise in extending the use of this inexpensive and durable technology by eliminating a portion of resistive losses. Desired improvements to the technology include reductions in electrode void fraction, crossover, and shunt current. Lower void fractions increase current density by allowing aqueous ions to both migrate and react at a greater portion of the electrode surface. The geometry investigated utilizes a design in which electrolyte feed is injected from the manifolds directly into the porous electrode without an intermediary flow field, which promotes product gas expulsion 1. Crossover is of particular concern because it puts a lower constraint on the practical thickness of the porous separator. Different modes of operation are investigated in this work to understand what provokes gas crossover locally, as previously done 1. Shunt current arises whenever an electrolyte solution is fed to a stack containing multiple electrodes contacted in series, inducing potential gradients in the electrolyte and leading to ion migration. This can lead to local potential gradients in the manifolds that allow undesired corrosion of the current collectors to occur. This three-dimensional (3-D) computational fluid dynamics model of an ADWE stack of five cells in series aims to gather details of the aforementioned problems, notably how they vary in 3-D space. Void fractions and crossover are compared between simulations of co- and counter-current operation. The locations of potential gradients that threaten the lifespan of the system are identified, and this information is used to suggest strategies to reduce or mitigate high void fraction, high local crossover, and high potential gradients in manifolds. Additionally, as this is a stack model, through-plane current distributions and notes on the fluid flow rates from cell to cell are provided. References J. S. Lopata, S-G. Kang, H-S. Cho, C-H. Kim, J. W. Weidner, S. Shimpalee, Electrochim. Acta, 390, 138802 (2021). Figure 1

A 24-year-old man presented to our outpatient clinic with the left tinnitus and otalgia, which had awakened him early in the morning. Otoendoscopic examination revealed an earwig crawling in the external auditory canal. The earwig was carefully taken out with ear forceps. The tympanic membrane and external auditory canal were normal without traumatic lesions, and audiometric testing revealed normal hearing. Earwigs are insects of the order Dermaptera, and the name "earwig" originated from an ancient superstition that earwigs burrow through the external auditory canal and eat sleeping persons’ brains. Although this superstition turned out to be unfounded, the earwigs sometimes do enter the ear.

A 75-year-old patient complained of mastication-induced clicking tinnitus on the left side, and otoendoscopic examination revealed that the left tympanic membraneTM was outwardly bulged by clenching her teeth. Temporal bone computed tomography demonstrated that the posteromedial bony wall of the glenoid was partially dehiscent, allowing herniation of soft tissue contents of temporomandibular joint into the middle ear. Increased middle ear pressure due to soft tissue herniation can induce left tympanic membrane bulging and accompanying clicking tinnitus. Herniation of temporomandibular joint soft tissue into the middle ear should be considered as a differential diagnosis when clicking tinnitus is evoked by mastication. Keywords: Tinnitus, Mastication, Temporomandibular joint, Middle ear, Foramen of Huschke

Economic uncertainty analysis of employing a membrane reactor (MR) equipped with H2O separation membranes for a synthetic natural gas (SNG) production as simultaneous power-to-gas and CO2 utilization technologies was carried out. Based on previously reported reaction kinetics, process simulation models were created for a conventional packed-bed reactor (PBR) and an MR. Deterministic economic analysis showed the unit SNG production cost of 1.67 $ kgSNG−1 in an MR compared to 1.82 $ kgSNG−1 in a PBR for a SNG production capacity of 1000 kg d−1, showing about 8% cost reductions in the MR. From sensitivity analysis, raw material and labor were identified as the key economic factors to affect a unit SNG production cost for all cases studied. Stochastic economic analysis using a Monte-Carlo simulation method provided better insights for economic-uncertainty associated with premature technology like a SNG production in an MR using H2O separation membranes by presenting a wide range of SNG production costs and their probability.

Water electrolysis for hydrogen and oxygen production is a key technology in next-generation energy carrier and conversion. In particular, renewable energy sources integrated water electrolysis system has emerged due to its eco-friendly and highly energy efficient process. However, inherent limitations of renewable energy sources including intermittent and unpredictable energy production restrict stable water electrolysis cell operating. Therefore, investigation on cell performance depending on various operation conditions is absolutely required. Here, we synthesized Ni-Fe layered double hydroxide (Ni-Fe LDH) electrodes and studied their oxygen evolution reaction (OER) activities under various operational conditions matching actual environmental conditions when utilizing renewable energy sources. Changes in morphology and electrocatalytic performance were systematically studied by using XRD, FE-SEM, and EIS measurement. Our results showed that operation of water electrolysis cell in an accelerated stress condition could result in changes in morphology of crystal structure of LDH, thus restricting ions to be fully utilized at active site for OER.

김정은 체제가 2013년 3월 당중앙위원회 전원회의에서 공식적으로 내세운 국가핵심전략은 ‘경제건설과 핵무력건설 병진노선’이었다. 핵무력을 증대하여 전쟁억지력과 방위력을 갖추고 국가안보를 확보하여 경제건설에 진력하겠다는 것이다. 북한에서는 병진노선을 ‘정의의 핵보검’이라 하며, 항구적인 국가전략노선이라 하였다. 2016년과 2017년 동안에 경제발전 5개년 계획을 추진하는 등 인민생활향상에 힘을 쏟기도 하였지만, 수차례의 핵실험과 미사일 시험발사를 강행하면서 ‘국가핵무력건설’을 완성하였다. 2018년 김정은 위원장은 신년사를 통하여 자신들은 어떠한 위협에도 대응할 만큼 ‘강한 전쟁억제력’을 갖추어 미국도 어찌하지 못할 것이라 하면서도, 대남문제에 대해서는 남북관계개선을 강하게 주장하였다. 북한이 문재인 정부의 국정목표인 ‘평화와 번영의 한반도’의 시그널을 받아들여 평창동계올림픽에 참가의사를 밝혔다. 남북관계에 새로운 모멘텀이 마련되었고, 고위급의 상호방문이 이루어지면서 남북정상회담에 합의하였다. 남북정상회담을 바로 앞둔 2018년 4월 20일 당중앙위원회 전원회의를 개최하여 병진노선의 전략을 수정하였다. 병진노선의 과업 완수를 선언하고 ‘경제건설 총력집중’노선이라는 새로운 국가전략을 제시하였다. 이는 대내외정책의 방향전환을 의미하는 것으로 비핵화에 대한 실행의지도 포함되었다. 이 연구는 북한이 병진노선을 어떻게 이끌어 왔으며, 핵무력 완성의 의미를 살펴본다. 왜 만능의 보검이라고 하던 핵을 내려놓고 경제건설 총력집중노선으로 전환했는지를 나름대로 분석해봄과 동시에 새로운 노선을 추진하는데 제약 요소는 무엇이며, 과연 지속될 것인지를 규명해 보려한다.

An iron-based oxygen carrier can convert natural gas into chemicals (syngas or hydrogen) with controlled CO2 emission in a redox process. Mixed ionic-electronic conductor (MIEC)-supported iron oxides have shown high catalytic activity by facilitating inward O anion diffusion. However, their durability has been tested under limited conditions, and key factors affecting the degradation of MIEC-supported iron oxides have rarely been identified. In this work, we find that the inherent redox stability and electronic conductivity of the support material are decisive properties that determine the redox stability and activity of iron oxide/MIEC composites, such as perovskite-type La0.8Sr0.2FeO3−δ and fluorite-type Ce0.9Gd0.1O2−δ, over 100 redox cycles with the redox pair Fe – Fe2O3 at 900 °C. The low redox stability of the Fe2O3/La0.8Sr0.2FeO3−δ composite oxygen carrier is closely related to that of La0.8Sr0.2FeO3−δ and the extreme redox environment. The increased electronic conductivity of Ce0.9Gd0.1O2−δ under reducing conditions enhances the reaction rate. However, the low electronic conductivity of Ce0.9Gd0.1O2−δ under oxidizing conditions (5 × 10−4 S/cm at 750 °C) progressively promotes the formation of iron oxide product layer, resulting in low syngas selectivity (H2/CO > 2). This work helps design and select a compatible and commercially viable MIEC-supported iron oxide.

Light cupula is an emerging concept accounting for positional nystagmus. It can be diagnosed when persistent geotropic direction-changing positional nystagmus (PG DCPN) is observed in a head-roll test. Although hypotheses explaining light cupula phenomenon such as "light debris", "lighter cupula", and "heavier endolymph" have been proposed, the mechanism underlying light cupula has not been clearly elucidated yet. In the present study, we proposed a new hypothesis accounting for light cupula, i.e., density difference between perilymph and endolymph could elicit characteristic PG DCPN in a head-roll test. We also discussed the mechanism how membranous canal containing endolymph became buoyant within the perilymphatic space under constant influence of gravity when the density of perilymph was higher than that of endolymph.

Primary tumors arising from the external auditory canal (EAC) are rare. We describe two cases of mass lesions within the EAC causing slowly progressive hearing loss without otorrhea or otalgia. Otoendoscopic examination demonstrated total obstruction of the EAC, and pure tone audiometry revealed conductive hearing loss. Based on the findings of the histopathologic examination, one patient was diagnosed with venous hemangioma that was treated using surgical resection, and the other patient was diagnosed with diffuse large B-cell lymphoma (DLBCL) that was treated using external-beam radiation therapy. Although primary tumors in the EAC are rare, both benign tumors such as venous hemangiomas and malignant lesions such as DLBCL should be considered as possible differential diagnoses of mass lesions in the EAC.

H2 is regarded as an alternative to current energy carriers without CO2 emission. To supplement traditional H2 production by fossil fuels, alkaline water electrolysis (AWE) is back in the spotlight. Unfortunately, H2 production by AWE is not economically practical yet compared with current fossil fuel H2 production methods. In this context, scenario analysis was performed in this study to find a suitable and reasonable scenario in which AWE is cost-competitive in terms of the levelized cost of H2 (LCOH) on the basis of diverse economic parameters such as the unit electricity price, the learning curve, and the automation level. From scenario analysis results, it is identified that the unit electricity price is the most effective economic factor to determine the LCOH followed by the learning curve and the automation level demonstrating that the introduction of surplus electricity, inevitably generated from renewable sources, can be very crucial for H2 production from AWE to be economically viable compared with the estimated LCOH of 1.25 USD per kg H2 in 2030 targeted by the United States Department of Energy. Most importantly, it can provide technical and economic guidelines on the basis of scenario analysis results. This can be very useful for decision makers to make economic and environmental policies in Korea and will result in entering the H2 economy society in the near future.