• 한국연소학회:학술대회논문집
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• 한국연소학회 2012년도 제45회 KOSCO SYMPOSIUM 초록집
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• pp.179-182
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• 2012

Effect of double post injections on diesel PCCI combustion with focus on HC emission was investigated in a single-cylinder direct-injection diesel engine. The ISFC, HC and CO emissions were reduced by single or double post injections. The application of double post injections could also improve the trade-off relationship between NOx and HC emissions under wide EGR rate range.

• 대한자원환경지질학회:학술대회논문집
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• 대한자원환경지질학회 2007년도 춘계 지질과학기술 공동학술대회
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• pp.127-129
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• 2007

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• Clinics in Shoulder and Elbow
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• 제25권1호
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• pp.73-89
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• 2022

Background: To evaluate the efficacy of autologous platelet-rich plasma (PRP) injections in the treatment of common shoulder diseases. Methods: The PubMed, Medline, and Central databases and trial registries were searched from their inception to October 2020 for randomized controlled trials of autologous PRP injections for shoulder diseases versus placebo or any control intervention. Preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed in the selection, analysis, and reporting of findings. The primary outcome was pain intensity (visual analog scale), and secondary outcomes were changes in function and quality of life (QoL). Results: A total of 17 randomized controlled trials of PRP versus control were analyzed. From 8-12 weeks to ≥1 year, PRP injections were associated with better pain relief and functional outcomes than control interventions. PRP injections were also associated with greater QoL, with an effect size of 2.61 (95% confidence interval, 2.01-14.17) at medium-term follow-up. Compared with placebo and corticosteroid injections, PRP injections provided better pain relief and functional improvement. In subgroup analyses, trials in which PRP was prepared by the double centrifugation technique, the platelet concentration in the PRP was enriched ≥5 times, leucocyte-rich PRP was used, or an activating agent was used before application reported the most effective pain relief at 6-7 months. Conclusions: PRP injections could provide better pain relief and functional outcomes than other treatments for persons presenting with common shoulder diseases. PRP injections have a greater capacity to improve shoulder-related QoL than other interventions.

• 한국자동차공학회논문집
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• 제19권3호
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• pp.99-105
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• 2011

This paper described the effect of the multiple injections on the emission characteristics and combustion stability in a common rail diesel engine. In order to investigate the influence of multiple injections in a passenger car diesel engine, the injection strategy was varied with pilot injection, post injection and one main injection at various conditions. Based on the experimental results, the combustion and emissions characteristics were analyzed for the various injection strategies such as main, pilot-main, double-pilot-main, double- pilot-main-post injection strategy. It is revealed that the $NO_X$, HC and CO emissions are reduced by double pilot and post injection at medium load, however, soot emission is increased. Also, in the case of multiple injection, the combustion pressure is increased smoothly near the TDC and the coefficient of variation and fuel consumptions are decreased.

• Journal of Dental Anesthesia and Pain Medicine
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• 제23권3호
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• pp.163-171
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• 2023

Background: Surgical extraction of impacted mandibular third molars is the most common procedure performed by oral surgeons. The procedure cannot be performed effectively without achieving profound anesthesia. During this procedure, patients may feel pain during surgical bone removal (at the cancellous level) or during splitting and luxation of the tooth, despite administration of routine nerve blocks. Administration of intraosseous (IO) lignocaine injections during third molar surgeries to provide effective anesthesia for pain alleviation has been documented. However, whether the anesthetic effect of lignocaine is the only reason for pain alleviation when administered intraosseously remains unclear. This conundrum motivated us to assess the efficacy of IO normal saline versus lignocaine injections during surgical removal of impacted mandibular third molars. The aim of this study was to assess the efficacy of IO normal saline as a viable alternative or adjunct to lignocaine for alleviation of intraoperative pain during surgical removal of impacted mandibular third molars. Methods: This randomized, double-blind, interventional study included 160 patients who underwent surgical extraction of impacted mandibular third molars and experienced pain during surgical removal of the buccal bone or sectioning and luxation of the tooth. The participants were divided into two groups: the study group, which included patients who would receive IO saline injections, and the control group, which included patients who would receive IO lignocaine injections. Patients were asked to complete a visual analog pain scale (VAPS) at baseline and after receiving the IO injections. Results: Of the 160 patients included in this study, 80 received IO lignocaine (control group), whereas 80 received IO saline (study group) following randomization. The baseline VAPS score of the patients and controls was 5.71 ± 1.33 and 5.68 ± 1.21, respectively. The difference between the baseline VAPS scores of the two groups was not statistically significant (P > 0.05). The difference between the numbers of patients who experienced pain relief following administration of IO lignocaine (n=74) versus saline (n=69) was not statistically significant (P > 0.05). The difference between VAPS scores measured after IO injection in both groups was not statistically significant (P >0.05) (1.05 ± 1.20 for the control group vs. 1.72 ± 1.56 for the study group) Conclusion: The study demonstrates that IO injection of normal saline is as effective as lignocaine in alleviating pain during surgical removal of impacted mandibular third molars and can be used as an effective adjunct to conventional lignocaine injection.

• The Korean Journal of Pain
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• 제35권1호
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• pp.14-21
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• 2022

The coronavirus disease 2019 (COVID-19) pandemic, which has been rampant since the end of 2019, has evidently affected pain management in clinical practice. Fortunately, a COVID-19 vaccination program is currently in progress worldwide. There is an ongoing discussion that pain management using steroid injections can decrease COVID-19 vaccine efficacy, although currently there is no direct evidence to support this statement. As such, the feeling of pain in patients is doubled in addition to the co-existing ill-effects of social isolation associated with the pandemic. Thus, in the COVID-19 era, it has become necessary that physicians be able to provide high quality pain management without negatively impacting COVID-19 vaccine efficacy. Steroids can alter the entire process involved in the generation of adaptive immunity after vaccination. The period of hypophysis-pituitary-adrenal axis suppression is known to be 1 to 4 weeks after steroid injection, and although the exact timing for peak efficacy of COVID-19 vaccines is slightly different for each vaccine, the average is approximately 2 weeks. It is suggested to avoid steroid injections for a total of 4 weeks (1 week before and after the two vaccine doses) for the double-shot vaccines, and for 2 weeks in total (1 week before and after vaccination) for a single-shot vaccine. This review focuses on the basic concepts of the various COVID-19 vaccines, the effect of steroid injections on vaccine efficacy, and suggestions regarding an appropriate interval between the administration of steroid injections and the COVID-19 vaccine.

• 한국분무공학회지
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• 제17권1호
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• pp.1-8
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• 2012

This study described the effect of the multiple injections and diesel-ethanol on the NVH, combustion and emission characteristics of 4 cylinder common rail diesel engine. In order to investigate the influence of diesel-ethanol blended fuel in a light-duty common rail diesel engine, the injection strategy was varied with pilot injection, double pilot injections, and one main injection at various operating conditions. The results showed that diesel-ethanol blended fuel had longer ignition delay than that of the ultra low diesel fuel(ULSD). Also, in the case of multiple injections, the combustion pressure is increased smoothly near the TDC and the NVH are decreased. In the emission characteristics, diesel-ethanol blended fuel produced lower indicated specific nitrogen oxides(IS-NOX) and indicated specific Soot(IS-soot) emissions, however, indicated specific unburned hydrocarbon(IS-HC) and indicated specific carbon monoxide(IS-CO) emissions are slightly increased.

• 대한두개안면성형외과학회지
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• 제19권1호
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• pp.64-67
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• 2018

Varying degrees of complications can occur after hyaluronic acid filler injections. Tissue necrosis due to interruption of the vascular supply is an early complication that can be severe. If the site of tissue necrosis due to the filler injection is the forehead, successfully reconstructing the region without distorting the key landmarks is challenging. We describe the case of a 50-year-old man who experienced widespread forehead skin necrosis after hyaluronic acid filler injection in the glabellar area. We successfully covered the forehead area with a $3{\times}4-cm^2$ midline necrotic tissue using the modified double-opposing rotation-advancement flap method. Although modified double-opposing rotation-advancement flap closure has the disadvantage of leaving a longer scar compared to conventional double-opposing rotation-advancement flap closure, the additional incision line made along the superior border of the eyebrow aids in camouflaging the scar and decreases eyebrow distortion. Therefore, it is believed that the modified double-opposing rotation-advancement flap technique is an excellent tool for providing adequate soft tissue coverage and minimal free margin distortion when reconstructing widespread skin necrosis in the central mid-lower forehead that can occur after filler injection in the glabellar area.

• 한국연소학회지
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• 제22권1호
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• pp.1-7
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• 2017

This paper presents an experimental study on the effect of double injection strategies on combustion characteristics in a single-cylinder diesel engine. These studies are applied to the double injection strategies, such as $2^{nd}$ injection timing variations with fixed injection interval (8 degree) and variations of injection pressures with fixed injection timing and intervals. The injection quantity was 7 + 7 mg for double injections, and 14 mg for single injection. When the injection pressure was increased, the ignition delay was shortened, and the ISFC (indicated specific fuel consumption) was increased due to the fast termination of combustion by the shortened energizing duration. In addition, the retardation of injection timings toward TDC (top dead center) caused the reduction of ignition delay and the decrease of ISFC with the decrease of FMEP (friction mean effective pressure).

• International Journal of Automotive Technology
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• 제6권6호
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• pp.579-584
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• 2005

Unsteady state free natural gas jets injected from several types of injectors were numerically simulated. Simulations showed good agreements with the schlieren experimental results. Moreover, injections of natural gas in intake manifolds of a single-valve engine and a double-valve engine were predicted as well. Predictions revealed that large volumetric injections of natural gas in intake manifolds led to strong impingement of natural gas with the intake valves, which as a result, gave rise to pronounced backward reflection of natural gas towards the inlets of intake manifolds, together with significant increase in pressure in intake manifold. Based on our simulations, we speculated that for engines with short intake manifolds, reflections of the mixture of natural gas and air were likely to approach the inlets of intake manifolds and subsequently be inbreathed into other cylinders, resulting in non-uniform mixture distributions between the cylinders. For engines with long intake manifolds, inasmuch as the degrees of intake interferences between the cylinders were not identical in light of the ignition sequences, non-uniform intake charge distributions between the cylinders would occur.