• Archives of Plastic Surgery
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• v.44 no.6
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• pp.482-489
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• 2017

Background Polydeoxyribonucleotide (PDRN) is known to have anti-inflammatory and angiogenic effects and to accelerate wound healing. The aim of this study was to investigate whether PDRN could improve peripheral tissue oxygenation and angiogenesis in diabetic foot ulcers. Methods This was a prospective randomized controlled clinical trial. Twenty patients with a non-healing diabetic foot ulcer were randomly distributed into a control group (n=10) and a PDRN group (n=10). Initial surgical debridement and secondary surgical procedures such as a split-thickness skin graft, primary closure, or local flap were performed. Between the initial surgical debridement and secondary surgical procedures, 0.9% normal saline (3 mL) or PDRN was injected for 2 weeks by the intramuscular (1 ampule, 3 mL, 5.625 mg, 5 days per week) and perilesional routes (1 ampule, 3 mL, 5.625 mg, 2 days per week). Transcutaneous oxygen tension ($TcPO_2$) was evaluated using the Periflux System 5000 with $TcPO_2/CO_2$ unit 5040 before the injections and on days 1, 3, 7, 14, and 28 after the start of the injections. A pathologic review (hematoxylin and eosin stain) of the debrided specimens was conducted by a pathologist, and vessel density (average number of vessels per visual field) was calculated. Results Compared with the control group, the PDRN-treated group showed improvements in peripheral tissue oxygenation on day 7 (P<0.01), day 14 (P<0.001), and day 28 (P<0.001). The pathologic review of the specimens from the PDRN group showed increased angiogenesis and improved inflammation compared with the control group. No statistically significant difference was found between the control group and the PDRN group in terms of vessel density (P=0.094). Complete healing was achieved in every patient. Conclusions In this study, PDRN improved peripheral tissue oxygenation. Moreover, PDRN is thought to be effective in improving inflammation and angiogenesis in diabetic foot ulcers.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1339-1348
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• 2015

Until now, considerable effort has been made to engineer novel nitrogen-fixing organisms through the transfer of nif genes from various diazotrophs to non-nitrogen fixers; however, regulatory coupling of the heterologous nif genes with the regulatory system of the new host is still not well understood. In this work, a 49 kb nitrogen fixation island from P. stutzeri A1501 was transferred into E. coli using a novel and efficient transformation strategy, and a series of recombinant nitrogen-fixing E. coli strains were obtained. We found that the nitrogenase activity of the recombinant E. coli strain EN-01, similar to the parent strain P. stutzeri A1501, was dependent on external ammonia concentration, oxygen tension, and temperature. We further found that there existed a regulatory coupling between the E. coli general nitrogen regulatory system and the heterologous P. stutzeri nif island in the recombinant E. coli strain. We also provided evidence that the E. coli general nitrogen regulator GlnG protein was involved in the activation of the nif-specific regulator NifA via a direct interaction with the NifA promoter. To the best of our knowledge, this work plays a groundbreaking role in increasing understanding of the regulatory coupling of the heterologous nitrogen fixation system with the regulatory system of the recipient host. Furthermore, it will shed light on the structure and functional integrity of the nif island and will be useful for the construction of novel and more robust nitrogen-fixing organisms through biosynthetic engineering.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1299-1305
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• 1996

The rat thoracic aorta was harvested to determine whether either hyperkalemla or hypothermia impairs the endothelium-dependent re axation of the vascular smooth muscle. Isolated thoracic aorta segments were studied in five groups(n=10 in each group). In group I(control), the isolated aortic seglnents were suspended in organ bath without any intervention. In group ll(endotheilum removAl). the endothelium of the aortic segment was removed by gentle rubbing of the intimal surface with a pair of forceps. In group III(457), IV(4mST), and V(3757), the aortic segments were exposed for 45minutes to 4$^{\circ}C$ St. Thomas hospital cardioplegic solution(57 : NaCl, 144.3; KCI, 19.6, MgCl:, 15.7 : CaCl, 2.2 mmol/L).4$^{\circ}C$ modified St. Thomas hospital cardioplegic solution(NaCl, 144.3 : KCI. 140.0 : MgCl:, 15.7; CaCl:. 2.2 mmol/L). and 37$^{\circ}C$ 57, before suspending in the organ bath, respectively. Then, aorta segments were suspended in organ baths(physiologic salt solution, 37$^{\circ}C$, 95% oxygen and 5% carbon dioxide) for Isometric tension recording. The vasodilatation to acetylcholine (10-2 to 10-2mol/L) was not impaired in control, 457, 4mST, nd 3757 groups. The vasodilatation to acetylcholine was impaired in endothelium removal group. The vasodilatation to sodium nitroprusslde (10-2 to 10-2 mol/L) was not impaired in all groups. In conclusion, both hyperkalemia and hypothermia do not alter irreversibly the function of the rondothelium of the thoracic aorta of the rat.

• Journal of The Korean Dental Society of Anesthesiology
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• v.14 no.2
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• pp.101-106
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• 2014

Background: Remifentanil, an ultra-short-acting mu-opioid receptor agonist, is unique from other opioids because of its esterase-based metabolism, minimal accumulation, and very rapid onset and offset of clinical action. Remifentanil can prevent the inflammatory response and can suppress inducible nitric oxide synthase expression in a septic mouse model. However, the effects of remifentanil on human keratinocyte and autophagy have yet to be fully elucidated during hypoxia-reoxygenation. Here we investigated whether remifentanil confers protective effect against hypoxia-reoxygenation in human keratinocyte and, if so, whether autophagy mediates this effect. Methods: The human keratinocytes were cultured under 1% oxygen tension. The cells were gassed with 94% $N_2$, and 5% $CO_2$ and incubated for 24 h at $37^{\circ}C$. To determine whether the administration of affects human keratinocytes hypoxia-reoxygenation injury, cells were then exposed to various concentrations of remifentanil (0.01, 0.1, 0.5 and 1 ng/ml) for 2 h. After remifentanil treatment, to simulate reoxygenation and recovery, the cells were reoxygenated for 12 h at $37^{\circ}C$. Control group did not receive remifentanil treatment. Normoxia group did not receive hypoxia and remifentanil treatment for 36 h. 3-MA group was treated 3-methyladenine (3-MA) for 1h before remifentanil treatment. Cell viability was measured using a quantitative colorimetric assay with MTT, showing the mitochondrial activity of living cells. Cells were stained with fluorescence and analyzed with Western blot analysis to find out any relations with activation of autophagy. Results: Prominent accumulation of autophagic specific staining MDC was observed around the nuclei in RPT group HaCaT cells. Similarly, AO staining, red fluorescent spots appeared in RPT group HaCaT cells, while the Normoxia, control and 3-MA groups showed mainly green cytoplasmic fluorescence. We here examined activation of autophagy related protein under H/R-induced cells by Western blotting analysis. Atg5, Beclin-1, LC3-II (microtubule-associated protein 1 light chain 3 form II) and p62 was elevated in RPT group cells. But they were decreased when autophagy was suppressed by 3-MA (Fig. 5). Conclusions: Although the findings of this study are limited to an in vitro interpretation, we suggest that remifentanil may have a beneficial effect in the recovery of wound from hypoxia-reoxygenation injury.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.4
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• pp.357-364
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• 1999

This study measures the influence of grass cover on water use and shoot growth of apple trees growing under different soil water regimes in temperate climate conditions and evaluates monthly crop coefficients of such conditions during four months of the growing season in 1995. To do so, double pot lysimeter experiments of 3-year-old Fuji' apple (Males domestica Borkh.) trees under a transparent rain shield were designed and installed. Trees were triplicate under three soil water regimes: (A) drip-irrigation at -50 kPa of soil matric potential (IR50). (B) drip-irrigation at -80 kPa of soil matric potential (IR80), and (C) constant shallow water table at 0.45 m below the soil surface (WT45). In each treatment, two soil surface conditions were tested: the soil surface bare, and covered with turf grasses. Mean monthly water use increased with increasing soil matric potential for drip irrigation and was greatest in the WT45 treatment. Monthly crop coefficients increased linearly in time for drip-irrigated apple trees ($r^2$ values of $0.953^{***}$ for turf grass-covered system and of $0.862^{***}$ for bare surface system), while those obtained in the WT45 treatment fluctuated, Duncan's multiple range tests for shoot growth showed that grass-covered IR50 was most favorable to apple trees. while bare surface waterlogged situation was most adverse at least in part due to a lack of oxygen in the root zone. Mid-season leaf Kjeldahl-N was higher in drip-irrigated apple trees than in WT45 trees, while soil Kjeldahl-N was not different irrespective of treatments.

• Tuberculosis and Respiratory Diseases
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• v.82 no.3
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• pp.251-260
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• 2019

Background: Beyond its current function as a rescue therapy in acute respiratory distress syndrome (ARDS), extracorporeal membrane oxygenation (ECMO) may be applied in ARDS patients with less severe hypoxemia to facilitate lung protective ventilation. The purpose of this study was to evaluate the efficacy of extended ECMO use in ARDS patients. Methods: This study reviewed 223 adult patients who had been admitted to the intensive care units of 11 hospitals in Korea and subsequently treated using ECMO. Among them, the 62 who required ECMO for ARDS were analyzed. The patients were divided into two groups according to pre-ECMO arterial blood gas: an extended group (n=14) and a conventional group (n=48). Results: Baseline characteristics were not different between the groups. The median arterial carbon dioxide tension/fraction of inspired oxygen ($FiO_2$) ratio was higher (97 vs. 61, p<0.001) while the median $FiO_2$ was lower (0.8 vs. 1.0, p<0.001) in the extended compared to the conventional group. The 60-day mortality was 21% in the extended group and 54% in the conventional group (p=0.03). Multivariate analysis indicated that the extended use of ECMO was independently associated with reduced 60-day mortality (odds ratio, 0.10; 95% confidence interval, 0.02-0.64; p=0.02). Lower median peak inspiratory pressure and median dynamic driving pressure were observed in the extended group 24 hours after ECMO support. Conclusion: Extended indications of ECMO implementation coupled with protective ventilator settings may improve the clinical outcome of patients with ARDS.

• Korean Chemical Engineering Research
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• v.57 no.5
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• pp.620-627
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• 2019

In this study, ignition delay characteristics of various bio aviation fuels (Bio-ADD, Bio-6308, Bio-7720) produced by HEFA process using different raw materials were compared and analyzed. In order to confirm the feasibility of applying bio aviation fuel to actual system, ignition delay characteristics of petroleum-based aviation fuel (Jet A-1) and blended aviation fuel (50:50, v:v) also analyzed. Ignition delay time of each aviation fuel was measured by using CRU, surface tension measurement and GC/MS and GC/FID analysis were performed to interpret the results. As a result, ignition delay time of Jet A-1 was the longest at all temperature because it contains aromatic compounds about 22.8%. The aromatic compounds can produce benzyl radical which is thermally stable and has low reactivity with oxygen during decomposition process. In the case of bio aviation fuels, ignition delay times were measured similarly because the ratio of n-paraffin/iso-paraffin constituting each aviation fuel is similar (about 0.12) and the composition ratio of cycloparaffin also has no difference. In addition, ignition delay times of blended aviation fuels (50:50, v:v) were measured close to the mean value those of each fuel so it was confirmed that it can be applied without any changing or improving of existing system.

• Tuberculosis and Respiratory Diseases
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• v.40 no.1
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• pp.16-22
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• 1993

Background: The Microbicidal and cytotoxic activities of neutrophils are to a large extent dependent on a burst of oxidative metabolism which generates superoxide anion, hydrogen peroxide, and other reactive products of oxygen. The respiratory burst of PMN is initiated by intracellular calcium mobilization that follows immune or particular stimulation and is very sensitive to modulation by c-AMP or adenosine. Despite its antagonism against adenosine, earlier study has demonstrated potent theophylline inhibition of the PMN respiratory burst at variable ranges of blood concentrations of theophylline in the healthy normal volunteers and in the septic animals pretreated or early post-treated with aminophylline (AMPH) or pentoxifylline. However it is unclear whether theophylline inhibits the superoxide generation or not in the established human sepsis caused by acute pneumonia, as taking into consideration of the fact that full activation of neutrophils have occurred within minutes after the septic insult in the animal experiments. Methods: We measured the $O_2$ generation of peripheral arterial neutrophils obtained from 11 human septic subjects caused by acute pneumonia before and 1 hour after completion of continuous AMPH infusion. Patients were identified and studied within 48 hour of admission. All subjects were administered an intravenous loading and maintenance dose of AMPH. The generation of $O_2$ was measured at a discrete time point (60 min) by the reduction of ferricytochrome c.PMA (10 ${\mu}g/ml$) was used as a stimulating agent. PMNs were isolated at a concentration of $2{\times}10^6$ cells/ml. The arterial oxygen tension, blood pressure and heart rates were also checked to evaluate the systemic effects of AMPH in the acute pneumonia. Results: The mean serum concentration of AMPH at 60 minutes was $8.8{\pm}0.6{\mu}g/ml$. Sixty minutes after AMPH infusion the generatition of $O_2$ was decreased from $0.076{\pm}0.034$ to $0.013{\pm}0.004$(OD) (p<0.05) and from $0.177{\pm}0.044$ to $0.095{\pm}0.042$(OD) (p<0.01) in the resting and stimulated PMNs respectively. $PaO_2$ was not changed after AMPH infusion. Conclusion: AMPH may compromise host defense by significant inhibition of neutrophil release of superoxide anion and it had no effect on improving $PaO_2$ in the acute pneumonia.

• Tuberculosis and Respiratory Diseases
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• v.44 no.6
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• pp.1326-1331
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• 1997

Background : Weaning is the process of switching a patient from mechanical ventilator to spontaneous breathing. A number of different weaning techniques can be employed. At recent study, conventional spontaneous breathing trial was superior to other techniques, such as intermittent mandatory ventilation(IMV) or pressure support ventilation(PSV). But adequate observation time of the spontaneous breathing trial was not determined. We reported the effectiveness of weaning and extubation following a 60 minutes spontaneous breathing trial with simple oxygen supply through the endotrachial tube. In this study, we tried to shorten the spontaneous breathing time from 60 minutes to 30 minutes. If weaning success was predicted after 30 minutes spontaneous breathing, extubation was done without reconnection with ventilator. Methodes : Subjects consisted of 42 mechanically ventilated patients from August 1994 to July 1995. The weaning trial was done when the patients recovered sufficiently from respiratory failure that originally required ventilatory assistance, the patients became alert and showed stable vital sign, and arterial $O_2$ tension was adequated($PaO_2$ > 55 mmHg) with less than 40% of inspired oxygen fraction. We conducted a careful physical examination when the patients was breathing spontaneously through the endobronchial tube for 30 minutes. We terminated the trial if a patients was any of following signs of distress; cyanosis, diaphoresis, tachypnea(above 30 breaths per minute), and extreme tachycardia. Patients who had none of this features during spontaneous breathing for 30 minutes were extubated promptly. Result : 17 weaning trials of 15 patients were done in 42 mechanically ventilated patients. Successful weaning and extubation was possible in 14 trials of total 17 trials. In this 14 patients, 8 patients were extubated after 30 minutes spontaneous breathing, 3 patients were extubated after 60 minutes spontaneous breathing, and 3 patients needed over 3 hours for extubation from weaning. We found similar overall success rate compared with weaning following a 60 minutes spontaneous breathing trial. Conclusion : From the result of present study, we believe that weaning and extubation from mechanical ventilation following a 30 minutes spontaneous breathing with $O_2$ supply through the endotracheal tube is a simple and effective method.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.1
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• pp.1-10
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• 2018

Recently, there has been rapid development in the field of flexible electronic devices, such as organic light emitting diodes (OLEDs), organic solar cells and flexible sensors. Encapsulation process is added to protect the flexible electronic devices from exposure to oxygen and moisture in the air. Using numerical simulation, we investigated the effects of the encapsulation layer on mechanical stability of the silicon chip, especially the fracture performance of center crack in multi-layer package for various loading condition. The multi-layer package is categorized in two type - a wide chip model in which the chip has a large width and encapsulation layer covers only the chip, and a narrow chip model in which the chip covers both the substrate and the chip with smaller width than the substrate. In the wide chip model where the external load acts directly on the chip, the encapsulation layer with high stiffness enhanced the crack resistance of the film chip as the thickness of the encapsulation layer increased regardless of loading conditions. In contrast, the encapsulation layer with high stiffness reduced the crack resistance of the film chip in the narrow chip model for the case of external tensile strain loading. This is because the external load is transferred to the chip through the encapsulation layer and the small load acts on the chip for the weak encapsulation layer in the narrow chip model. When the bending moment acts on the narrow model, thin encapsulation layer and thick encapsulation layer show the opposite results since the neutral axis is moving toward the chip with a crack and load acting on chip decreases consequently as the thickness of encapsulation layer increases. The present study is expected to provide practical design guidance to enhance the durability and fracture performance of the silicon chip in the multilayer package with encapsulation layer.