Performance Improvement of a High Side Scroll Compressor by Thrust Surface Oil Groove

Performance analysis has been carried out on a high side scroll compressor having a fixed scroll equipped with a circular oil groove on its thrust surface. Oil is supplied to the oil groove through an intermittent opening from a high pressure oil reservoir formed inside the orbiting scroll hub. Oil in the groove is then delivered to both suction and back pressure chambers by pressure differentials and viscous pumping action of the orbiting scroll base plate. Mathematical modeling of this oil groove system has been incorporated into main compressor performance simulation program for optimum oil groove design. Pressure in the oil groove can be controlled by changing the oil passage area and oil groove configuration. With an enlarged oil passage, pressure in the oil groove increases due to increased flow rate, but pressure increase in the back pressure chamber is not that large, resulting in reduced friction loss at the thrust surface between the two scrolls. On the other hand, by increasing the oil passage area, oil content in the refrigerant flow increases, and the orbiting scroll stability could be negatively affected by oil groove pressure increase. Considering all these factors, EER could be improved by about 3.6% at ARI condition by optimum oil groove design

The Formation of Colonial Landscape and Its Sociocultural Meanings in Korean Rural Society: A Case Study of Hwaho Village, North Chŏlla

Translated from the article published in Korean Cultural Anthropology vol. 43, no. 1, 2010, with permission from the Korean Society for Cultural Anthropology.This paper will delineate the historical and cultural meanings of the colonial landscape formed during Japanese colonization in the village of Hwaho in North Chŏlla province. The Japanese began arriving in Korea starting in the early 1900s. Once Japan colonized Korea officially in 1910, the Japanese moved in on a larger scale. They established Japanese communities in the midst of Korean communities regardless of what type of Korean community was already established, be it village, town, or city. The newly-formed Japanese communities in Korea looked exotic and authoritative to the colonized people. They began to be viewed as symbols of colonial domination. In addition to residential houses there were also administrative buildings and commercial shops. In rural areas, particularly those in the North Chŏlla plains which were known to be one of Koreas granary regions, rich Japanese landlords purchased vast tracts of agricultural land and established large farms along with offices, residences, storage facilities, commercial shops, schools and religious institutions. These new Japanese communities were seen as quite different from the Korean communities in both structure and form. I selected the village of Hwaho in North Chŏlla as the location for my fieldwork because the Japanese community still remains intact, including the old buildings, houses, school, as well as other sites and fields. More importantly, some old villagers in their 80s experienced the colonialism. Many studies on the colonial landscape in Korea have focused on cities such as the capital, Kyŏngsŏng (Seoul), and four other cities, Inchŏn, Pusan, Mokpo, and Kunsan, which were frontier cities in terms of both modernization and colonialism since they were treaty (open) ports to foreign vessels in the late 19th century. In comparison to scholarly attention to cities, the colonial modernization of farming areas attracts far less attention even though the farming villages actually experienced colonial modernization to a greater extent than cities. Aware of the importance of farming villages colonial modernization seen through the colonial landscape, I decided to study the village of Hwaho. I will examine study four aspects of colonial modernism in a Korean farming village: 1) the formation of the Japanese community and its socio-economic background, 2) the specific characteristics of colonial landscape of Hwaho, 3) the newly established socio-economic hierarchy in the village upon the arrival of Japanese immigrants including big and small capitalists and petty farmers, and 4) cultural meanings of the colonial landscape and its effect on the Korean villagers. Lastly, I discuss the characteristics of colonial modernity based on what the villagers experienced

Abnormalities of Otoacoustic Emissions in Myasthenia Gravis: Association With Serological and Electrophysiological Features

Objective: To investigate whether otoacoustic emissions (OAEs) are impaired in patients with myasthenia gravis (MG) and whether such dysfunction is associated with serological and electrophysiological features of MG.Methods: We tested 15 patients with MG (30 ears) and 10 healthy age- and sex-matched subjects (20 ears) for transiently evoked OAE (TEOAE) and distortion product OAE (DPOAE).Results: Compared with controls, MG patients revealed a significant reduction in the amplitude of TEOAEs (p < 0.05) and DPOAEs at higher frequencies between 2,026 and 4,053 Hz (p < 0.05). In the subgroup analysis, TEOAE and DPOAE amplitudes were significantly lower in the acetylcholine receptor (AChR) antibody-positive group (p < 0.05) as well as in the repetitive nerve stimulation (RNS)-positive (p < 0.05) group. In particular, the OAE alteration significantly correlated with anti-AChR antibody titers. No significant difference of the OAEs was found between thymomatous and non-thymomatous MG or between purely ocular and generalized MG.Conclusions: Our study confirms that OAEs reveal subclinical dysfunction of the cholinergic neurotransmission of cochlear outer hair cells and correlate well with electrophysiological and serological characteristics of MG patients. Our findings imply that the measurement of OAEs might increase the diagnostic accuracy and help to monitor the severity of MG

Satellite cell-specific ablation of Cdon impairs integrin activation, FGF signalling, and muscle regeneration

Background: Perturbation in cell adhesion and growth factor signalling in satellite cells results in decreased muscle regenerative capacity. Cdon (also called Cdo) is a component of cell adhesion complexes implicated in myogenic differentiation, but its role in muscle regeneration remains to be determined. Methods: We generated inducible satellite cell-specific Cdon ablation in mice by utilizing a conditional Cdon allele and Pax7 CreERT2. To induce Cdon ablation, mice were intraperitoneally injected with tamoxifen (tmx). Using cardiotoxin-induced muscle injury, the effect of Cdon depletion on satellite cell function was examined by histochemistry, immunostaining, and 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay. Isolated myofibers or myoblasts were utilized to determine stem cell function and senescence. To determine pathways related to Cdon deletion, injured muscles were subjected to RNA sequencing analysis. Results: Satellite cell-specific Cdon ablation causes impaired muscle regeneration with fibrosis, likely attributable to decreased proliferation, and senescence, of satellite cells. Cultured Cdon-depleted myofibers exhibited 32 ± 9.6% of EdU-positive satellite cells compared with 58 ± 4.4% satellite cells in control myofibers (P < 0.05). About 32.5 ± 3.7% Cdon-ablated myoblasts were positive for senescence-associated β-galactosidase (SA-β-gal) while only 3.6 ± 0.5% of control satellite cells were positive (P < 0.001). Transcriptome analysis of muscles at post-injury Day 4 revealed alterations in genes related to mitogen-activated protein kinase signalling (P < 8.29 e−5) and extracellular matrix (P < 2.65 e−24). Consistent with this, Cdon-depleted tibialis anterior muscles had reduced phosphorylated extracellular signal-regulated kinase (p-ERK) protein levels and expression of ERK targets, such as Fos (0.23-fold) and Egr1 (0.31-fold), relative to mock-treated control muscles (P < 0.001). Cdon-depleted myoblasts exhibited impaired ERK activation in response to basic fibroblast growth factor. Cdon ablation resulted in decreased and/or mislocalized integrin β1 activation in satellite cells (weak or mislocalized integrin1 in tmx = 38.7 ± 1.9%, mock = 21.5 ± 6%, P < 0.05), previously linked with reduced fibroblast growth factor (FGF) responsiveness in aged satellite cells. In mechanistic studies, Cdon interacted with and regulated cell surface localization of FGFR1 and FGFR4, likely contributing to FGF responsiveness of satellite cells. Satellite cells from a progeria model, Zmpste24−/− myofibers, showed decreased Cdon levels (Cdon-positive cells in Zmpste24−/− = 63.3 ± 11%, wild type = 90 ± 7.7%, P < 0.05) and integrin β1 activation (weak or mislocalized integrin β1 in Zmpste24−/− = 64 ± 6.9%, wild type = 17.4 ± 5.9%, P < 0.01). Conclusions: Cdon deficiency in satellite cells causes impaired proliferation of satellite cells and muscle regeneration via aberrant integrin and FGFR signalling. © 2020 The Authors. Journal of Cachexia, Sarcopenia and Muscle published by John Wiley & Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders1

Albumin-Like Protein is the Major Protein Constituent of Luminal Fluid in the Human Endolymphatic Sac

The endolymphatic sac (ES) is an inner ear organ that is connected to the cochleo-vestibular system through the endolymphatic duct. The luminal fluid of the ES contains a much higher concentration of proteins than any other compartment of the inner ear. This high protein concentration likely contributes to inner ear fluid volume regulation by creating an osmotic gradient between the ES lumen and the interstitial fluid. We characterized the protein profile of the ES luminal fluid of patients (n = 11) with enlarged vestibular aqueducts (EVA) by proteomics. In addition, we investigated differences in the protein profiles between patients with recent hearing deterioration and patients without hearing deterioration. The mean total protein concentration of the luminal fluid was 554.7±94.6 mg/dl. A total of 58 out of 517 spots detected by 2-DE were analyzed by MALDI-TOF MS. The protein profile of the luminal fluid was different from the profile of plasma. Proteins identified from 29 of the spots were also present in the MARC-filtered human plasma; however, the proteins identified from the other 25 spots were not detected in the MARC-filtered human plasma. The most abundant protein in the luminal fluid was albumin-like proteins, but most of them were not detected in MARC-filtered human plasma. The concentration of albumin-like proteins was higher in samples from patients without recent hearing deterioration than in patients with recent hearing deterioration. Consequently, the protein of ES luminal fluid is likely to be originated from both the plasma and the inner ear and considering that inner ear fluid volumes increase abnormally in patients with EVA following recent hearing deterioration, it is tempting to speculate that albumin-like proteins may be involved in the regulation of inner ear fluid volume through creation of an osmotic gradient during pathological conditions such as endolymphatic hydrops

Endothelial Function is Not Changed during Short-Term Withdrawal of Thyroxine in Patients with Differentiated Thyroid Cancer and Low Cardiovascular Risk

PURPOSE: The incidence of differentiated thyroid cancer is increasing in young adults and females in Korea. Some of them experience short-term hypothyroidism in preparation for radioiodine (RAI) therapy, which can have a deleterious effect on the cardiovascular system. However, it is not clear if short-term hypothyroidism induces endothelial dysfunction in patients with low cardiovascular risk. Therefore, the aim of this study was to investigate whether short-term hypothyroidism is associated with endothelial dysfunction in patients with low cardiovascular risk. MATERIALS AND METHODS: To evaluate the effect of short-term hypothyroidism on endothelial function in this group, we recruited fifteen female patients with low cardiovascular risk. We analyzed clinical, biochemical, and cardiovascular parameters at four time points: the last day on levothyroxine (LT4) at their usual thyroid-stimulating hormone (TSH)-suppressive doses (P1), 7 days (P2) and 4 weeks (P3) after withdrawal of LT4, and 8 weeks (P4) after replacement of the previous dose of LT4. A high resolution ultrasound was used to measure brachial artery diameter at rest, after reactive hyperemia, and after sublingual nitroglycerin. RESULTS: During short-term hypothyroidism (P3), serum concentrations of total cholesterol and low-density lipoprotein (LDL)-cholesterol were increased (p < 0.001 for each period). In spite of having worsened lipid states, serum high sensitivity C-reactive protein or flow-mediated vasodilatation, which is one of the surrogate markers of the endothelial function, did not change during short-term hypothyroidism. CONCLUSION: Short-term hypothyroidism induced worsening of metabolic parameters, but not enough to induce the endothelial dysfunction in patients with low cardiovascular riskope