Quantification of methane and carbon dioxide surface emissions from a metropolitan landfill based on quasi-continuous eddy covariance measurement.

The Sudokwon landfill (SL) in the Seoul metropolitan area, South Korea, is among the world's largest landfills, striving to curtail landfill gas (LFG) emissions and achieve carbon neutrality by 2050. Since 2005, the SL Management Corporation (SLC) has measured LFG emissions (i.e., methane (CH4) and carbon dioxide (CO2)) using a dynamic flux chamber proposed by the US EPA. However, uncertainty prevails in validating the reduction of LFG emissions due to the limited spatiotemporal data coverage. In 2020, an eddy covariance (EC) system was installed to enhance measurements, revealing highly fluctuating LFG emissions driven by waste layer LFG production, LFG collection, and atmospheric pressure changes. During the study period, the annual CH4 emission increased slightly from 465.0 ± 4.2 to 485.5 ± 6.4 g C m-2, while that of CO2 decreased by 2/3 (from 408.7 ± 16.5 to 270.6 ± 18.8 g C m-2), primarily due to the doubled CO2 uptake by the vegetated topsoil. Our first long-term (March 2020 to February 2022) quasi-continuous monitoring using EC (with a gap-filling and partitioning technique based on Random Forest) emphasizes the difficulty of temporal upscaling of discontinuously observed surface emissions to quantify the LFG inventory and the need for continuous observations or suitable proxies (e.g., atmospheric CH4 concentration).

Comparison of the 3D-Exoscope and Operating Microscope in Mastoidectomy.

OBJECTIVES: The operating microscope (OM) commonly used in ear surgeries has several disadvantages, including a low depth of field, a narrow field of view, and unfavorable ergonomic characteristics. The exoscope (EX) was developed to overcome these disadvantages. Herein, we compared OM and EX during mastoidectomy and found out the feasibility of the EX. STUDY DESIGN: Prospective randomized comparative study. SETTING: Tertiary academic medical center. PATIENTS: Patients who had mastoidectomy for chronic otitis media with or without cholesteatoma between January 2022 and April 2022. INTERVENTION: Canal wall-up mastoidectomy (CWUM) or canal wall-down mastoidectomy (CWDM) using OM or EX without endoscope. MAIN OUTCOME MEASURES: Operative setting time (the time between the end of general anesthesia and incision), operative time (from incision to suture), postoperative audiologic outcomes, perioperative complications, and the decision to switch from EX to OM. RESULTS: Of 24 patients who were diagnosed with chronic otitis media or cholesteatoma, 12 each were randomly assigned to the OM or EX group. The mean operation time was 175 ± 26.5 minutes and 172 ± 34.6 minutes in the EX and OM group, respectively, which was not significantly different ( p = 0.843). The procedures in the EX group were successfully completed using a three-dimensional (3D)-EX without conversion to OM. All surgeries were completed without any complications. The postoperative difference in the air and bone conduction was 11.2 and 12.4 dB in the EX and OM groups, respectively, which was not significantly different ( p = 0.551). CONCLUSIONS: EX is comparable to OM in terms of surgical time, complications, and audiologic outcomes following mastoidectomy. The EX system is a potential alternative to OM. However, further improvements are required to overcome some drawbacks (deterioration of image resolution at high magnification, requirement of an additional controller for refocusing).

The Korean Version of the Oxford Cognitive Screen (K-OCS) Normative Study.

OBJECTIVE: To generate a Korean version of the Oxford Cognitive Screen (K-OCS) and obtain cutoff scores that determine the impairment of each subdomain. Post-stroke cognitive impairment (PSCI) negatively impacts the rehabilitation process and independence in daily life. Its obscure manifestations require effective screening for appropriate rehabilitation. However, in most rehabilitation clinics, psychological evaluation tools for Alzheimer's dementia have been used without such considerations. The OCS is a screening assessment tool for PSCI and vascular dementia that can evaluate the cognitive domains most often affected by stroke, including language, attention, memory, praxis, and numerical cognition. It comprises 10 subtasks and enables quick and effective cognitive evaluation. METHODS: The K-OCS, which considers Korea's unique cultural and linguistic characteristics, was developed with the approval and cooperation of the original author. Enrollment of participants without disabilities was announced at Duksung Women's University, Yongin Sevrance Hospital, CHA Bundang Medical Center. The study was conducted between September 2020 and March 2022 on 97 male and female participants aged ≥30 years. RESULTS: All the 97 participants completed the task. In this study, the 5th percentile score was presumed to be the cutoff value for each score, and the values are provided here. The cutoff score for each OCS subtask was similar to that of the original British version. CONCLUSION: We suggest the usability of the K-OCS as a screening tool for PSCI by providing the cutoff value of each subtask.

Clinical characteristics of persistent postural-perceptual dizziness and its visual subtype in Korean patients: A multicenter cross-sectional study.

OBJECTIVES: Persistent postural-perceptual dizziness (PPPD) is a chronic functional vestibular disorder for which the Bárány Society has established diagnostic criteria. This nationwide multicenter study aims to investigate the clinical features of individuals with definite PPPD and clinical variant PPPD who do not fully meet the diagnostic criteria, with a particular focus on visual exaggeration. METHODS: Between September 2020 and September 2021, a total of 76 individuals with definite PPPD and 109 individuals with clinical variant PPPD who did not meet all three exacerbating factors outlined in Criterion B were recruited from 18 medical centers in South Korea. The study gathered information on demographic factors, clinical manifestations, balance scales, and personality assessments. RESULTS: Comparative analysis between groups with definite PPPD and clinical variant with visual exacerbation revealed no significant differences in sociodemographic characteristics, clinical course, dizziness impact, and specific precipitants. Only disease duration was significantly longer in definite PPPD compared with variant with visual exacerbation. However, the variant without visual exacerbation displayed significantly reduced rates of panic disorder, diminished space-motion discomfort, lesser impact of dizziness, and decreased prevalence of depression when compared with the definitive PPPD. CONCLUSION: This is the first comprehensive nationwide study examining clinical features of both definite PPPD patients and its clinical variants, considering visual exacerbating factors. Differences in dizziness and personality traits emerged between definite PPPD and its potential variant without visual issues. Our results highlight the possibility of a distinct clinical variant of PPPD influenced by visual dependency.

Hair Cell Regeneration: From Animals to Humans.

Cochlear hair cells convert sound into electrical signals that are relayed via the spiral ganglion neurons to the central auditory pathway. Hair cells are vulnerable to damage caused by excessive noise, aging, and ototoxic agents. Non-mammals can regenerate lost hair cells by mitotic regeneration and direct transdifferentiation of surrounding supporting cells. However, in mature mammals, damaged hair cells are not replaced, resulting in permanent hearing loss. Recent studies have uncovered mechanisms by which sensory organs in non-mammals and the neonatal mammalian cochlea regenerate hair cells, and outlined possible mechanisms why this ability declines rapidly with age in mammals. Here, we review similarities and differences between avian, zebrafish, and mammalian hair cell regeneration. Moreover, we discuss advances and limitations of hair cell regeneration in the mature cochlea and their potential applications to human hearing loss.

The Effectiveness of Salvage Hyperbaric Oxygen Therapy Following Combined Steroid Therapy for Refractory Sudden Sensorineural Hearing Loss.

OBJECTIVE: Hyperbaric oxygen therapy (HBOT) is an accepted treatment option for sudden sensorineural hearing loss (SSNHL), but it is still recommended in combination with corticosteroids. We investigated the efficacy of salvage HBOT in refractory SSNHL that does not respond to corticosteroid combination therapy. METHODS: Eighty-four patients were included, who had unilateral SSNHL with an improvement of pure-tone average (PTA) less than 10 dB after using intratympanic plus systemic corticosteroids (combined therapy) as the initial therapy. The control group (n = 66) received no further treatment, and the HBOT group (n = 18) received additional treatment with HBOT (10 sessions in total with 2.5 atmospheres absolute for 1 hour). RESULTS: No differences in PTA or WDS were found between the 2 groups. However, the mean hearing gain in the HBOT group (16.8 ± 4.49 dB) was significantly higher than that in the control group (4.45 ± 1.03 dB) (P = .015). The proportion of patients with hearing recovery (hearing gain of 10 dB or more) after treatment was significantly higher in HBOT group (38.9%) than in the control group (10.6%). CONCLUSIONS: In patients with refractory SSNHL after steroid combined therapy, salvage HBOT showed a significant effect on hearing gain and recovery rate.

Prospective Study of Nonsurgical Auricular Correction According to Timing of Treatment.

BACKGROUND AND PURPOSE: Many studies recommend nonsurgical auricular correction during the early postnatal period, when cartilage plasticity is high; however, many patients are not eligible for the procedure. This study compared different timings of nonsurgical auricular correction to investigate benefit after the optimal period for correction. METHODS: In this prospective study, 53 ears from 35 patients with congenital auricular anomaly were assigned to two groups according to age at correction: the "early-group" with correction within 2 weeks of birth and "late-group" with correction 8 weeks after birth. Aesthetic outcomes, caregiver satisfaction, detachment rates and mean device-wearing periods, were compared. RESULTS: Thirty-one ears from 20 patients comprised the early-group, and 18 ears from 12 patients comprised the late-group. Mean time to treatment after birth was 9.09 days in the early-group and 134.7 days in the late-group. In the early-group, detachment occurred in 4/31 ears (12.9%), and in the late-group, detachment occurred in 12/18 ears (66.7%), which was statistically significant (p<0.01). The average period of applying devices was 4.7 ± 1.2 weeks in the early-group and 8.5 ± 4.1 weeks in the late-group, with a significantly longer treatment time in the late-group (p=0.001). The early-group had 87.1% "good" results vs. 55.6% in the late-group, with a statistically significant difference. CONCLUSIONS: The correction period was shorter, detachment rate was lower, and treatment outcome was better in the early-group. However, successful correction was also present in the late-group, showing that the patients who have passed the optimum correction period should proceed after counselling.

Differences in the metabolomic profile of the human palatine tonsil between pediatrics and adults.

Palatine tonsils (PT) are B cell-predominant lymphoid organs that provide primary immune responses to airborne and dietary pathogens. Numerous histopathological and immunological studies have been conducted on PT, yet no investigations have been conducted on its metabolic profile. We performed high-resolution magic angle spinning nuclear magnetic resonance spectroscopy-based metabolic profiling in 35 pediatric and 28 adult human palatine tonsillar tissue samples. A total of 36 metabolites were identified, and the levels of 10 metabolites were significantly different depending on age. Among them, partial correlation analysis shows that glucose levels increased with age, whereas glycine, phosphocholine, phosphoethanolamine, and ascorbate levels decreased with age. We confirmed the decrease in immunometabolic activity in adults through metabolomic analysis, which had been anticipated from previous histological and immunological studies on the PT. These results improve our understanding of metabolic changes in the PT with aging and serve as a basis for future tonsil-related metabolomic studies.

Effects of Particulate Matter Exposure on the Eustachian Tube and Middle Ear Mucosa of Rats.

OBJECTIVES: Particulate matter (PM) is a risk factor for various diseases. Recent studies have established an association between otitis media (OM) and PM exposure. To confirm this relationship, we developed a novel exposure model designed to control the concentration of PM, and we observed the effects of PM exposure on the Eustachian tube (ET) and middle ear mucosa of rats. METHODS: Forty healthy, 10-week-old, male Sprague-Dawley rats were divided into 3-day, 7-day, 14-day exposure, and control groups (each, n=10). The rats were exposed to incense smoke as the PM source for 3 hours per day. After exposure, bilateral ETs and mastoid bullae were harvested, and histopathological findings were compared using microscopy and transmission electron microscopy (TEM). The expression levels of interleukin (IL)-1ß, IL-6, tumor necrosis factor-α, and vascular endothelial growth factor (VEGF) in the middle ear mucosa of each group were compared using real-time reverse transcription polymerase chain reaction (RT-PCR). RESULTS: In the ET mucosa of the exposure group, the goblet cell count significantly increased after PM exposure (P=0.032). In the middle ear mucosa, subepithelial space thickening, increased angio-capillary tissue, and inflammatory cell infiltration were observed. Moreover, the thickness of the middle ear mucosa in the exposure groups increased compared to the control group (P<0.01). The TEM findings showed PM particles on the surface of the ET and middle ear mucosa, and RT-PCR revealed that messenger RNA (mRNA) expression of IL-1ß significantly increased in the 3-day and 7-day exposure groups compared to the control group (P=0.035). VEGF expression significantly increased in the 7-day exposure group compared to the control and 3-day exposure groups (P<0.01). CONCLUSION: The ET and middle ear mucosa of rats showed histopathologic changes after acute exposure to PM that directly reached the ET and middle ear mucosa. Therefore, acute exposure to PM may play a role in the development of OM.

Outcomes of Endoscopic Tympanoplasty for Large Perforations: A Multicenter Retrospective Study in South Korea.

OBJECTIVES: Endoscopic tympanoplasty (ET) provides minimally invasive transcanal access to the middle ear and improves middle ear visibility for the treatment of tympanic membrane (TM) perforations. However, the literature on surgical outcomes for large TM perforations is lacking and limited to small series. This study aimed to evaluate the clinical benefits of ET for large TM perforations. METHODS: This retrospective cohort study was conducted at nine tertiary referral hospitals in South Korea, where 252 patients who underwent ET as primary surgery from September 2019 to August 2021 were included. The outcome measures included the graft success rate and pre- and postoperative audiometric data. RESULTS: In 239 patients, the graft success rate of ET for large or subtotal perforations was 86.2% (206 patients), while the graft failure rate was 13.8% (33 patients). The graft failure rate was directly correlated with surgical techniques, including overlay and medial or lateral underlay tympanoplasty (P=0.027). Lateral underlay tympanoplasty showed the most favorable. RESULTS: Sex, laterality, etiology, site and size of perforation, operation time, and graft materials did not vary significantly between the graft success and failure groups (P>0.05). The mean air-bone gap (ABG) improved significantly in both groups (graft success group: 10.0±0.6 dB and graft failure group: 7.7±0.3 dB; P<0.001). However, the ABG improvement did not significantly differ between the groups. Analysis of covariance revealed that the postoperative 500-Hz bone conduction threshold improved after successful ET (adjusted coefficient, -11.351; 95% confidence interval, -21.491 to -1.212; P=0.028). CONCLUSION: This study involved the largest population to date of large TM perforations treated by ET. The study findings suggest that ET is feasible and effective in treating large TM perforations.

Three-dimensional imaging performance of photoelectrochemical cells.

A photoelectrochemical (PEC) cell produces hydrogen energy using solar energy and an electrochemical reaction. In the hydrogen production process with water decomposition, electrons move from the anode to the cathode, and by measuring the current value at this time, the PEC cell can generate hydrogen and function as an image sensor at the same time. Due to the characteristics of the PEC cell that can perform both functions simultaneously, it can be applied as a device that can detect and respond to the surrounding environment without the need for an observation system such as a camera. We present the imaging performance of PEC cells. The effectiveness of the experiment was confirmed by applying the PEC cells to integral imaging, one of the three-dimensional (3D) imaging techniques.

Surgical Removal of Hearing Aid Earmold Impression Material in the Middle Ear.

When fitting hearing aids, patients are required to make an earmold impression material for device fixation. It usually causes no problems, although in rare cases, the earmold passes through the middle ear through tympanic membrane perforations.1-3 Foreign bodies may cause a delayed inflammatory reaction and deterioration of aeration, especially in the Eustachian tube. Herein, we report a rare case of earmold impression material as a foreign body in the middle ear that required surgical removal.

The Optimized Protocol of Hyperbaric Oxygen Therapy For Sudden Sensorineural Hearing Loss.

OBJECTIVE: This study aimed to determine the optimal protocol of hyperbaric oxygen therapy (HBOT) according to various treatment settings for sudden sensorineural hearing loss (SSNHL). METHODS: A 112 patients with SSNHL were enrolled in this prospective study. All patients were treated with systemic steroid therapy, intratympanic steroid therapy, and HBOT. According to the pressure and duration of HBOT (10 sessions in total), the patients were divided into three groups: group 1, 2.5 atmospheres absolute (ATA) for 1 h; group 2, 2.5 ATA for 2 h; and group 3, 1.5 ATA for 1 h. The pure-tone average (PTA), word discrimination score (WDS), and mean gain were compared. RESULTS: A total of 105 patients completed the 3-month follow-up, and 6 patients were excluded. Differences among groups were found in PTA, WDS, and mean gain. In the post-hoc analysis, group 3 had significantly lower WDS and mean gain than groups 1 and 2; however, group 2 showed no significant differences from group 1. The proportion of patients with hearing recovery after treatment was significantly higher in group 1 (57.6%) and group 2 (58.8%) than in group 3 (31.3%). CONCLUSIONS: When HBOT (10 sessions) was combined with corticosteroids as the initial therapy for SSNHL, a higher pressure (1.5 ATA vs. 2.5 ATA) provided better treatment results; however, increasing the duration (1 h vs. 2 h) under 2.5 ATA did not result in a significant difference. Therefore, HBOT for SSNHL may be performed at 2.5 ATA for 1 h in 10 sessions. Laryngoscope, 133:383-388, 2023.

Auricular Reconstruction for Bilateral Auricular Deformity Caused by Relapsing Polychondritis.

This case report describes a woman in her early 20s who presented to the hospital with an acquired auricular deformity after an ear piercing and was diagnosed with recurrent polychondritis that required total auricular reconstruction.

Phenolic compounds in common buckwheat sprouts: composition, isolation, analysis and bioactivities.

Phenolic compounds in common buckwheat sprouts (CBSs) have gained research interest because of their multiple health benefits. Phenolic acids, flavanones, flavonols, flavan-3-ols, and anthocyanins are important bioactive components of CBS that exhibit biological activities, including anti-inflammatory, antioxidant, anti-proliferative, and immunomodulatory effects. The isolation and quantitative and qualitative analyses of these phenolic compounds require effective and appropriate extraction and analytical methods. The most recent analytical method developed for determining the phenolic profile is HPLC coupled with a UV-visible detector and/or MS. This review highlights the extraction, purification, analysis, and bioactive properties of phenolic compounds from CBS described in the literature.

Patulous eustachian tube after balloon eustachian tuboplasty in a post-radiation patient.

BACKGROUND: Balloon eustachian tuboplasty (BET) is a minimally invasive surgical treatment that is effective and safe for obstructive eustachian tube dysfunction. However, BET complications include excessive widening of the eustachian tube, causing a patulous eustachian tube (PET). Herein, we report a case of PET following BET in a patient who underwent radiation therapy and reviewed the literature on considerations for reducing complications after BET. CASE PRESENTATION: A 63-year-old woman complained of bilateral ear fullness after concurrent chemoradiation therapy for nasopharyngeal lymphoma. BET was performed on the left side because the left-sided serous otitis media persisted. A left-sided PET was performed two weeks after the BET, along with eustachian tube silicone plug insertion on the left side. The patient became asymptomatic immediately after the surgery, with no recurrence reported after a 12-month follow-up period. CONCLUSIONS: To our knowledge, there has been no report of PET following BET in a post-radiation patient, and it was successfully treated via ET silicone plug insertion.

Clinical features and prognosis of severe-to-profound sudden sensorineural hearing loss.

PURPOSE: Sudden sensorineural hearing loss (SSNHL) is an otologic emergency. Despite multiple efforts to clarify the factors affecting the prognosis of severe-to-profound SSNHL, various studies showed inconsistent results and lack of clinical significance. Therefore, we examined the clinical features and outcomes of severe-to-profound SSNHL. MATERIALS AND METHODS: We included patients who experienced SSNHL between 2018 and 2021 and were diagnosed according to the American Academy of Otolaryngology-Head and Neck Surgery criteria; hearing loss over 70 dB on initial pure tone audiometry (PTA) was used to define severe-to-profound SSNHL. We retrospectively examine the demographic, laboratory, radiologic, and audiometric data of SSNHL patients. We also evaluated the final hearing gain of these patients by assessing their PTA findings and word-recognition scores. RESULTS: Of the 178 patients, 94 (52.81%) and 84 (47.19%) showed profound (>90 dB) and severe (>70 to 90 dB) hearing loss, respectively. The presence of vertigo and hypertension differed significantly between the severe and profound groups (p < 0.001 and p = 0.012, respectively), as did the initial serum creatinine level (p = 0.043). Recovery in PTA showed a reliable correlation with the interval between onset and treatment in the severe group and periventricular white-matter findings in the profound group (p < 0.001 and p = 0.011, respectively). The presence of hypertension was related to recovery of low tone (p = 0.023 for 250 Hz; p = 0.034 for 500 Hz), while glycated hemoglobin level was related to recovery of high tone in the severe group (p = 0.049 for 4000 Hz; p = 0.047 for 8000 Hz). CONCLUSIONS: Severe-to-profound SSNHL showed poor prognosis for hearing gain. The interval from onset to treatment was a significant prognostic factor for severe SSNHL, while the presence of vertigo, estimated glomerular filtration rate, and periventricular white-matter findings were significant prognostic factors for profound SSNHL.