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

A case of diabetic ketoacidosis with posterior cerebral artery territory ischemic stroke mimicking uncal herniation

In diabetic ketoacidosis, hyperglycemia and ketosis result in cerebral vasculitis, which can cause cerebral edema and thrombosis. A previously healthy, 12-year-old girl visited the emergency department with a history of vomiting, polydipsia, polyuria, decreased mentality, and a 7 kg (12%) weight loss within 1 week. She showed laboratory features of severe diabetic ketoacidosis, stuporous mentality, respiratory failure, and unilateral fixed mydriasis with contralateral hemiparesis. However, brain magnetic resonance imaging showed multifocal ischemic stroke mainly involving the left posterior cerebral artery territory, instead of uncal herniation. This case highlights the possible occurrence of ischemic stroke in children with early-stage diabetes mellitus

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

Cloning and Characterization of a Flavonol Synthase Gene from Scutellaria baicalensis

Flavonols are the most abundant of all the flavonoids and play pivotal roles in a variety of plants. We isolated a cDNA clone encoding flavonol synthase from Scutellaria baicalensis (SbFLS). The SbFLS cDNA is 1011 bp long, encodes 336 amino acid residues, and belongs to a family of 2-oxoglutarate-dependent dioxygenases. The overall structure of SbFLS is very similar to that of Arabidopsis thaliana anthocyanidin synthase (AtANS), with a β jelly-roll fold surrounded by tens of short and long α-helices. SbFLS was constitutively expressed in the roots, stems, leaves, and flowers, with particularly high expression in the roots and flowers. SbFLS transcript levels in the roots were 376-, 70-, and 2.5-fold higher than in the leaves, stems, and flowers. The myricetin content was significantly higher than that of kaempferol and quercetin. Therefore, we suggest that SbFLS mediates flavonol formation in the different organs of S. baicalensis. Our study may contribute to the knowledge of the role of FLS in S. baicalensis

Definitions of unfavorable surgical outcomes and their risk factors based on disability score after spine surgery for lumbar spinal stenosis

Risk factors for unfavorable surgical outcomes are dependent on the definitions of the unfavorable surgical outcomes. The aims of this study were to compare risk factors for each unfavorable surgical outcome according to two different definitions of unfavorable surgical outcomes after surgery for lumbar spinal stenosis (LSS) as well as compare the clinical course from the preoperative period to 3 years postoperatively between cases with favorable and unfavorable outcomes according to the two different definitions. Overall, 295 patients who underwent spine surgery for LSS and a follow-up evaluation at 3 years postoperatively were enrolled and divided into favorable and unfavorable groups, based on two different definitions for unfavorable surgical outcomes, as evaluated at 12 months postoperatively: the patient-reported outcome (PRO) and minimal clinically important difference (MCID) methods. In the PRO method, patients with a postoperative Oswestry Disability Index (ODI) score > 22 were considered as having an unfavorable outcome, whereas in the MCID method, those with a postoperative ODI score that changed < 12.8 points from the preoperative value were classified as having an unfavorable outcome. As a primary outcome, risk factors for unfavorable surgical outcomes according to each definition were investigated at 12 months postoperatively. In the PRO method, female sex (P = 0.011; odds ratio (OR): 2.340), elementary school attainment (vs. university attainment; P = 0.035; OR: 2.875), and higher preoperative ODI score (P = 0.028; OR: 2.340) were associated with higher odds for an unfavorable surgical outcome. In the MCID method, a higher preoperative ODI score was associated with higher odds (P < 0.001; OR: 0.920) of a favorable surgical outcome. In the PRO method, the favorable outcome group demonstrated significantly lower visual analog scale for back and leg pain and lower ODI scores than the unfavorable outcome group at 3 years postoperatively, whereas in the MCID method, clinical outcomes were not different between the two groups at 3 years postoperatively. A higher preoperative ODI score may be a risk factor for postoperative ODI > 22 after surgery for LSS. It may also be associated with higher odds for improvements in the ODI score of > 12.8.This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2016R1A2B3012850)

Does gender influence the impact of impaired renal function on prognosis after ST-segment elevated myocardial infarction?

Background: A limited number of studies have investigated the impact of gender on renal function and clinical outcomes after ST-segment elevated myocardial infarction (STEMI), and these studies have provided discrepant results.Methods and Results: This study was based on a retrospective cohort, the Korean Acute Myocardial Infarction Registry (KAMIR). Patients (n = 7,679) with a discharge diagnosis of STEMI were analyzed to investigate association of gender with renal function and clinical outcomes. Compared to men, women were older and exhibited more comorbidity, including impaired renal function. Women showed higher mortality compared to men (1-month mortality,5.6% in men vs. 12.6% in women, p &lt; 0.001; 1-year mortality, 6.8% in men vs. 14.4% in women, p &lt; 0.001). The risk of death proportionally increased as estimated glomerular filtration rate (eGFR) decreased in both genders. After adjusting for potential confounders, hazard ratios for women did not significantly differ from those for men at each eGFR level.The interaction test showed no significant interaction between gender and eGFR in 1-month mortality and 1-year mortality.Conclusions: Impaired renal function was an independent prognostic factor after STEMI in both genders, and the impact of impaired renal function on prognosis after STEMI did not significantly differ between genders

A Novel Biomarker of Coronary Atherosclerosis: Serum DKK1 Concentration Correlates with Coronary Artery Calcification and Atherosclerotic Plaques

DKK1 modulates Wnt signaling, which is involved in the atherosclerosis. However, no data exist regarding the usefulness of measuring serum DKK1 concentration in predicting coronary atherosclerosis. A total of 270 consecutive patients (62.8 ± 11.2 yr; 70% male) were included. A contrast-enhanced 64-slice coronary MDCT was performed to identify the presence of atherosclerotic plaques. Agatston calcium scores (CS) were calculated to quantify the coronary artery calcification (CAC). DKK1 concentrations were measured by enzyme-linked immunosorbent assay. For each subsequent DKK1 quartile, there was a significant increase in CAC (P = 0.004) and the number of segments with coronary atherosclerosis (P < 0.001). In addition, DKK1 concentration was significantly higher in patients with atherosclerotic plaques, regardless of plaque composition (P = 0.01). Multivariate analysis identified DKK1 as an independent risk factor for the presence of coronary atherosclerotic plaque. The adjusted odds ratio for coronary atherosclerotic plaque was 4.88 (95% CI, 1.67 to 14.25) for highest versus lowest quartile of the DKK1 levels. Furthermore, patients with DKK1 concentrations ≥ 68.6 pg/mL demonstrated coronary atherosclerotic plaques even when they had low CS. Serum DKK1 concentrations correlate with the coronary atherosclerosis and play an independent role in predicting the presence of coronary atherosclerosis

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&apos;-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 &lt; 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 &lt; 0.001). Transcriptome analysis of muscles at post-injury Day 4 revealed alterations in genes related to mitogen-activated protein kinase signalling (P &lt; 8.29 e−5) and extracellular matrix (P &lt; 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 &lt; 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 &lt; 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 &lt; 0.05) and integrin β1 activation (weak or mislocalized integrin β1 in Zmpste24−/− = 64 ± 6.9%, wild type = 17.4 ± 5.9%, P &lt; 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 &amp; Sons Ltd on behalf of Society on Sarcopenia, Cachexia and Wasting Disorders1

Significant association of SREBP-2 genetic polymorphisms with avascular necrosis in the Korean population

<p>Abstract</p> <p>Background</p> <p>It is known that steroid usage and alcohol abuse are major etiological factors in the development of avascular necrosis (AVN), a bone disease that produces osteonecrosis of the femoral head. The facilitation of fat biosynthesis by steroids and alcohol disrupts the blood supply into the femoral head. <it>SREBP-2 </it>plays a central role in the maintenance of lipid homeostasis through stimulating expression of genes associated with cholesterol biosynthetic pathways. The aim of this study was to examine the association between the polymorphisms of the <it>SREBP-2 </it>gene and AVN susceptibility in the Korean population.</p> <p>Methods</p> <p>Four single nucleotide polymorphisms (SNP) in the <it>SREBP-2 </it>gene, IVS1+8408 T>C (rs2267439), IVS3-342 G>T (rs2269657), IVS11+414 G>A (rs1052717) and IVS12-1667 G>A (rs2267443), were selected from public databases and genotyped in 443 AVN patients and 273 control subjects by using single-based extension (SBE) genotyping.</p> <p>Results</p> <p>The minor allele (C) frequency of rs2267439 showed a significant protective effect on AVN (P = 0.01, OR; 0.75, 95% CI; 0.604–0.935), and the genotype frequencies of this polymorphism were also different from the controls in all alternative analysis models (P range, 0.009–0.03, OR; 0.647–0.744). In contrast, rs1052717 and rs2267443 polymorphisms were significantly associated with AVN risk. Further analysis based on pathological etiology showed that the genotypes of rs2267439, rs1052717 and rs2267443 were also significantly associated with AVN susceptibility in each subgroup.</p> <p>Conclusion</p> <p>This study is the first report to evaluate the association between <it>SREBP-2 </it>gene polymorphisms and the susceptibility of AVN in the Korean population.</p