Spatiotemporal patterns of groundwater over South Korea.

Understanding the large-scale spatiotemporal pattern of multi-depth groundwater levels is critical to develop water management plans and policies for sustainable ecological and social prosperity, which are still lacking. Here, we investigate three major spatiotemporal modes of groundwater levels from ∼200 groundwater monitoring stations over the southern Korean Peninsula (2009-2020), using the Cyclostationary empirical orthogonal function analysis. The first two major modes are associated with the seasonality of recharge and discharge and groundwater use during the 2016/17 drought, which explained half of the total variance. The third major mode indicated a decreasing trend of deep groundwater levels over the western Korean Peninsula, where key administrative and authority offices have been relocated via balanced national land development policies. Furthermore, at least three million Koreans over this region likely experience groundwater depletion by the 2080s. Observational evidence of emerging groundwater depletion suggests a window of opportunity for pre-emptive groundwater management plans.

Dermoid cyst in the subcutaneous tissues of the back: A rare case with multimodal imaging and pathologic correlation.

Dermoid cysts are lined by keratinizing squamous epithelium and consist of skin appendages such as hair follicles, apocrine glands, and sebaceous glands. They are usually diagnosed during infancy or early childhood, commonly reported in the head and neck region. A dermoid cyst on the back is extremely rare, with only three cases in the pediatric and adult populations. We report a rare case of a dermoid cyst in the subcutaneous layer of the back in an adult. A 75-year-old man presented with a soft, painless mass on his left upper back. Computed tomography revealed a low-density mass nearly identical to the subcutaneous fat in the subcutaneous layer with nodular soft-tissue density components. It was a heterogeneously hyperechoic mass without internal vascularity on ultrasonography. On magnetic resonance imaging, the lesion showed nearly identical signal intensity (SI) to subcutaneous fat on T1 and T2-weighted images. The soft tissue component was intermediately hyperintense on T1- and T2- weighted images with enhancement. This lesion was pre-operatively suspected as a lipoma variant or a well-differentiated liposarcoma/atypical lipomatous tumor because of the fat density or SI and enhancing portion. We demonstrated and reviewed the multimodality imaging features of dermoid cysts at an unusual location and suggested imaging features that could help readers differentiate dermoid cysts from lipomatous tumors. When a mass shows fat density or SI with or without enhancing soft tissue components at the trunk or extremity, dermoid cysts as well as lipomatous tumors could be considered in the differential diagnosis.

Comparative In Vitro Biological Toxicity of Four Kinds of Air Pollution Particles.

Accumulating epidemiological evidence indicates that exposure to fine air pollution particles (APPs) is associated with a variety of adverse health effects. However, the exact physiochemical properties and biological toxicities of fine APPs are still not well characterized. We collected four types of fine particle (FP) (diesel exhaust particles [DEPs], natural organic combustion [NOC] ash, synthetic organic combustion [SOC] ash, and yellow sand dust [YSD]) and investigated their physicochemical properties and in vitro biological toxicity. DEPs were almost entirely composed of ultrafine particles (UFPs), while the NOC, SOC, and YSD particles were a mixture of UFPs and FPs. The main elements in the DEPs, NOC ash, SOC ash, and YSD were black carbon, silicon, black carbon, and silicon, respectively. DEPs exhibited dose-dependent mutagenicity even at a low dose in Salmonella typhimurium TA 98 and 100 strains in an Ames test for genotoxicity. However, NOC, SOC, and YSD particles did not show any mutagenicity at high doses. The neutral red uptake assay to test cell viability revealed that DEPs showed dose-dependent potent cytotoxicity even at a low concentration. The toxicity of DEPs was relatively higher than that of NOC, SOC, and YSD particles. Therefore, these results indicate that among the four FPs, DEPs showed the highest in vitro biological toxicity. Additional comprehensive research studies such as chemical analysis and in vivo acute and chronic inhalation toxicity tests are necessary to determine and clarify the effects of this air contaminant on human health.

Spatial and temporal changes in leaf coloring date of Acer palmatum and Ginkgo biloba in response to temperature increases in South Korea.

Understanding shifts in autumn phenology associated with climate changes is critical for preserving forest ecosystems. This study examines the changes in the leaf coloring date (LCD) of two temperate deciduous tree species, Acer palmatum (Acer) and Ginkgo biloba (Ginkgo), in response to surface air temperature (Ts) changes at 54 stations of South Korea for the period 1989-2007. The variations of Acer and Ginkgo in South Korea are very similar: they show the same mean LCD of 295th day of the year and delays of about 0.45 days year-1 during the observation period. The delaying trend is closely correlated (correlation coefficient > 0.77) with increases in Ts in mid-autumn by 2.8 days °C-1. It is noted that the LCD delaying and temperature sensitivity (days °C-1) for both tree species show negligible dependences on latitudes and elevations. Given the significant LCD-Ts relation, we project LCD changes for 2016-35 and 2046-65 using a process-based model forced by temperature from climate model simulation. The projections indicate that the mean LCD would be further delayed by 3.2 (3.7) days in 2016-35 (2046-65) due to mid-autumn Ts increases. This study suggests that the mid-autumn warming is largely responsible for the observed LCD changes in South Korea and will intensify the delaying trends in the future.

Tear progression of symptomatic full-thickness and partial-thickness rotator cuff tears as measured by repeated MRI.

PURPOSE: The purpose of this study was to analyse the natural course of symptomatic full-thickness and partial-thickness rotator cuff tears treated non-operatively and to identify risk factors affecting tear enlargement. METHODS: One hundred and twenty-two patients who received non-surgical treatment for a partial- or full-thickness supraspinatus tear were included in this study. All rotator cuff tears were diagnosed with magnetic resonance imaging (MRI), and the same modality was used for follow-up studies. Follow-up MRI was performed after at least a 6-month interval. We evaluated the correlation between tear enlargement and follow-up duration. Eleven risk factors were analysed by both univariate and multivariate analyses to identify factors that affect enlargement of rotator cuff tears. The mean follow-up period was 24.4 ± 19.5 months. RESULTS: Out of 122 patients, 34 (27.9%) patients had an initial full-thickness tear and 88 (72.1%) patients had a partial-thickness tear. Considering all patients together, tear size increased in 51/122 (41.8%) patients, was unchanged in 65/122 (53.3%) patients, and decreased in 6/122 (4.9%) patients. Tear size increased for 28/34 (82.4%) patients with full-thickness tears and 23/88 (26.1%) patients with partial-thickness tears. From the two groups which were followed over 12 months, a higher rate of enlargement was observed in full-thickness tears than in partial-thickness tears (6-12 months, n.s.; 12-24 months, P = 0.002; over 24 months, P < 0.001). Logistic regression revealed that having a full-thickness tear was the most reliable risk factor for tear progression (P < 0.001). CONCLUSIONS: This study found that 28/34 (82.4%) of symptomatic full-thickness rotator cuff tears and 23/88 (26.1%) of symptomatic partial-thickness tears increased in size over a follow-up period of 6-100 months. Full-thickness tears showed a higher rate of enlargement than partial-thickness tears regardless of the follow-up duration. Univariate and multivariate analyses suggested that full-thickness tear was the most reliable risk factor for tear enlargement. The clinical relevance of these observations is that full-thickness rotator cuff tears treated conservatively should be monitored more carefully for progression than partial-thickness tears. LEVEL OF EVIDENCE: IV.

Multiple etiologies of trigger wrist.

BACKGROUND: Trigger wrist, a relatively unusual condition, is a triggering at the wrist produced by wrist or finger motion. The clinical manifestations and surgical results of trigger wrist with multiple etiologies were evaluated. METHODS: From October 2008 to December 2012, this study retrospectively reviewed 15 patients diagnosed with trigger wrist. The patients comprised six men and nine women with a mean age of 44.8 years (range, 29-86 years). The mean follow-up period was 16.2 months (range, 11-30 months). RESULTS: The causes of trigger wrist were an anomalous muscle belly of the flexor digitorum superficialis (n = 5), severe tenosynovitis of the flexor tendon (n = 4), fibroma around the flexor tendon sheath (n = 2), a rheumatoid nodule (n = 1), both anomalous muscle belly and tenosynovitis (n = 1), a ganglion (n = 1), and pigmented villonodular synovitis (n = 1). Mild-to-moderate symptoms of median neuropathy without thenar muscle atrophy were present in all patients. Postoperatively, all patients recovered well with resolution of median nerve symptoms, and the wrist triggering was absent. CONCLUSIONS: Trigger wrist is a relatively rare condition compared with trigger finger, which is the most common disorder of the hand. To avoid inadequate and ineffective treatment of patients with trigger wrist, careful examination and proper diagnosis are vital. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic/IV.

Staged surgery for chronic primary aortoduodenal fistula in a septic patient.

Aortoenteric fistula is one of the most challenging problems that confront the vascular surgeons. Controversy remains over the optimal treatment because of the continued publication of series with high mortality, amputation, and aortic disruption rates. A positive preoperative blood culture is the best predictor of mortality with increased amputation rates due to infection of the extra-anatomic bypass. Therefore, in selected cases with sepsis, a prudent management protocol is required. We report a 68-yr-old male presenting with a chronic primary aortoduodenal fistula extensively involving the duodenum and Gram-negative sepsis. We planned a staged operation. Initially, an emergency laparotomy and control of the aorta allowed stabilization of the patient, identification of the fistula, and direct in situ placement of the prosthetic graft followed by an en bloc resection of the aneurysm and the surrounding structures. After he recovered from sepsis and had been stabilized, a staged extra-anatomic bypass followed by transabdominal removal of the temporarily placed graft was done. This management plan will allow the highest success rate and may be a prudent management protocol for these difficult cases.