• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.5
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• pp.2357-2380
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• 2019

In this paper, we investigate the impact of hardware impairments (HWIs) on the performance of a downlink massive MIMO system. We consider a single-cell system with maximum ratio transmission (MRT) as precoding scheme, and with all the HWIs characteristics such as phase noise, distortion noise, and amplified thermal noise. Based on the system model, we derive closed-form expressions for a typical user data rate under two scenarios: when a common local oscillator (CLO) is used at the base station and when separated oscillators (SLOs) are used. We also derive closed-form expressions for the downlink transmit power required for some desired per-user data rate under each scenario. Compared to the conventional system with ideal transceiver hardware, our results show that impairments of hardware make a finite upper limit on the user's downlink channel capacity; and as the number of base station antennas grows large, it is only the hardware impairments at the users that mainly limit the capacity. Our results also show that SLOs configuration provides higher data rate than CLO at the price of higher power consumption. An approach to minimize the effect of the hardware impairments on the system performance is also proposed in the paper. In our approach, we show that by reducing the cell size, the effect of accumulated phase noise during channel estimation time is minimized and hence the user capacity is increased, and the downlink transmit power is decreased.

• Genes and Genomics
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• v.40 no.12
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• pp.1279-1285
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• 2018

Interdigitating dendritic cell sarcoma (IDCS) is an aggressive neoplasm and is an extremely rare disease, with a challenging diagnosis. Etiology of IDCS is also unknown and most studies with only case reports. In our case, immunohistochemistry showed that the tumor cells were positive for S100, CD45, and CD68, but negative for CD1a and CD21. This study aimed to investigate the causative factors of IDCS by sequencing the protein-coding regions of IDCS. We performed whole-exome sequencing with genomic DNA from blood and sarcoma tissue of the IDCS patient using the Illumina Hiseq 2500 platform. After that, we conducted Sanger sequencing for validation of sarcoma-specific variants and gene ontology analysis using DAVID bioinformatics resources. Through comparing sequencing data of sarcoma with normal blood, we obtained 15 nonsynonymous single nucleotide polymorphisms (SNPs) as sarcoma-specific variants. Although the 15 SNPs were not validated by Sanger sequencing due to tumor heterogeneity and low sensitivity of Sanger sequencing, we examined the function of the genes in which each SNP is located. Based on previous studies and gene ontology database, we found that POLQ encoding DNA polymerase theta enzyme and FNIP1 encoding tumor suppressor folliculin-interacting protein might have contributed to the IDCS. Our study provides potential causative genetic factors of IDCS and plays a role in advancing the understanding of IDCS pathogenesis.

• Journal of Hydrogen and New Energy
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• v.31 no.5
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• pp.489-497
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• 2020

The Li-ion battery is considered to be one of the potential power sources for electric vehicles. In fact, the efficiency, reliability, and cycle life of Li-ion batteries are highly influenced by their thermal conditions. Therefore, a novel thermal management system is highly required to simultaneously achieve high performance and long life of the battery pack. Basically, thermal modeling is a key issue for the novel thermal management of Li-ion battery systems. In this paper, as a basic study for battery thermal modeling, temperature distributions inside the simple Li-ion battery pack (comprises of nine 18650 Li-ion batteries) under a 1C discharging condition were investigated using measurement and computational fluid dynamics (CFD) simulation approaches. The heat flux boundary conditions of battery cells for the CFD thermal analysis of battery pack were provided by the measurement of single battery cell temperature. The temperature distribution inside the battery pack were compared at six monitoring locations. Results show that the accurate estimation of heat flux at the surface of single cylindrical battery is paramount to the prediction of temperature distributions inside the Li-ion battery under various discharging conditions (C-rates). It is considered that the research approach for the estimation of temperature distribution used in this study can be used as a basic tool to understand the thermal behavior of Li-ion battery pack for the construction of effective battery thermal management systems.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.162-169
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• 2005

Network traffic measurements show that the data traffic on packet switched networks has the self-similar features which is different from the traditional traffic models such as Poisson distribution or Markovian process model. Most of the call admission control researches have been done on the performance analysis of a single network switch. It is necessary to consider the performance analysis of the proposed admission control scheme under interconnected switch environment because the data traffic transmits through switches in networks. From the simulation results, it is shown that the call admission control scheme may not operate properly on the interconnected switch even though the scheme works well on a single switch. In this parer, we analyze the cell loss probability, utilization and self-similarity of output ports of the interconnected networks switch by using shared buffer memory management schemes and propose the new call admission control scheme considering the interconnected network switches under self-similar traffic environments.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.329-336
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• 2023

Purpose: In this study, we aimed to compare the characteristics of patients with trauma by age group in a single center in Korea to identify the clinical characteristics and analyze the risk factors affecting mortality. Methods: Patients aged ≥18 years who visited the Chungbuk National University Hospital Regional Trauma Center between January 2016 and December 2022 were included. The accident mechanism, severity of the injury, and outcomes were compared by classifying the patients into group A (18-64 years), group B (65-79 years), and group C (≥80 years). In addition, logistic regression analysis was performed to identify factors affecting death. Results: The most common injury mechanism was traffic accidents in group A (40.9%) and slipping in group B (37.0%) and group C (56.2%). Although group A had the highest intensive care unit admission rate (38.0%), group C had the highest mortality rate (9.5%). In the regression analysis, 3 to 8 points on the Glasgow Coma Scale had the highest odds ratio for mortality, and red blood cell transfusion within 24 hours, intensive care unit admission, age, and Injury Severity Score were the predictors of death. Conclusions: For patients with trauma, the mechanism, injured body region, and severity of injury differed among the age groups. The high mortality rate of elderly patients suggests the need for different treatment approaches for trauma patients according to age. Identifying factors affecting clinical patterns and mortality according to age groups can help improve the prognosis of trauma patients in the future.

• Journal of Animal Science and Technology
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• v.66 no.3
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• pp.567-576
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• 2024

Subclinical ketosis (SCK) is a prevalent metabolic disorder that occurs during the transition to lactation period. It is defined as a high blood concentration of ketone bodies (beta-hydroxybutyric acid f ≥ 1.2 mmol/L) within the first few weeks of lactation, and often presents without clinical signs. SCK is mainly caused by negative energy balance (NEB). The objective of this study is to identify single nucleotide polymorphisms (SNPs) associated with SCK using genome-wide association studies (GWAS), and to predict the biological functions of proximal genes using gene-set enrichment analysis (GSEA). Blood samples were collected from 112 Holstein cows between 5 and 18 days postpartum to determine the incidence of SCK. Genomic DNA extracted from both SCK and healthy cows was examined using the Illumina Bovine SNP50K BeadChip for genotyping. GWAS revealed 194 putative SNPs and 163 genes associated with those SNPs. Additionally, GSEA showed that the genes retrieved by Database for Annotation, Visualization, and Integrated Discovery (DAVID) belonged to calcium signaling, starch and sucrose, immune network, and metabolic pathways. Furthermore, the proximal genes were found to be related to germ cell and early embryo development. In summary, this study proposes several feasible SNPs and genes associated with SCK through GWAS and GSEA. These candidates can be utilized in selective breeding programs to reduce the genetic risk for SCK and subfertility in high-performance dairy cows.

• Journal of Cerebrovascular and Endovascular Neurosurgery
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• v.25 no.2
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• pp.160-174
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• 2023

Objective: Carotid artery stenting (CAS) is currently widely used for the treatment of carotid artery stenosis. The objective of this study was to analyze the outcomes of CAS performed in a single institution. Methods: We retrospectively analyzed 313 CAS cases from January 2007 to December 2020, including 206 (66%) symptomatic and 107 (34%) asymptomatic cases. Procedure-related morbidity and mortality were assessed. Rates of periprocedural (≤30 days after CAS) and postprocedural ipsilateral strokes (>30 days after CAS) were also assessed. Logistic regression analysis was used to identify risk factors for the periprocedural complication, in-stent restenosis (ISR), and ipsilateral stroke. Results: The success rate of CAS was 98%. Among 313 cases, 1 patient died due to hyperperfusion-related intracerebral hemorrhage (ICH). The CAS-related mortality rate was 0.31%. The overall incidence of periprocedural complications is 5.1%. A risk factor for periprocedural complication was a symptomatic carotid artery stenosis (7.3% vs. 0.9%, p=0.016). Twenty cases of ISR occurred during 63.7±42.1 months of follow-up. The overall incidence of ISR was 10.2% (20/196). A risk factors for ISR were diabetes mellitus (17.6% vs. 5.7%, p=0.008) and patients who used Open-cell stents (19.6% vs. 6.9%, p=0.010). The overall incidence of ipsilateral stroke is 5.6%. A risk factors for ipsilateral stroke was ISR (95% CI, p=0.002). Conclusions: CAS is a safe and effective procedure for carotid artery stenosis. Although the incidence of complications is low, fatal complication such as hyperperfusion-related ICH can occur. To prevent hyperperfusion-related ICH, several methods such as strict blood pressure (BP) control, intentional less widening of stenotic segment should be used. To prevent ISR or stroke occurrence, special attention should be paid to patients who have ISR or ipsilateral stroke risk factors.

• Journal of Oral Medicine and Pain
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• v.38 no.3
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• pp.221-233
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• 2013

Bile acids are polar derivatives of cholesterol essential for the absorption of dietary lipids and regulate the transcription of genes that control cholesterol homeostasis. Recently it have been identified the synthetic chenodeoxycholic acid (CDCA) derivatives HS-1200 and cisplatin showed apoptisis-inducing activity on various cancer cells in vivo and in vitro. This study was undertaken to investigate the synergistic apoptotic effect of co-treatment with HS-1200 and cisplatin on human tongue squamous cell carcinoma cells (SCC25 cells). To investigate whether the co-treatment with HS-1200 and cisplatin compared to each single treatment efficiently reduces the viability of SCC25 cells, MTT assay was conducted. The induction and augmentation of apoptosis were confirmed by DNA electrophoresis, Hoechst staining and an analysis DNA hypoploidy. Westen blot analysis and immunofluorescent staining were also performed to evaluate the expression levels and the translocation of apoptosis-related proteins following this co-treatment. Furthermore, proteasome activity and mitochondrial membrane potential (MMP) change were also assayed. In this study, co-treatment with HS-1200 and cisplatin on SCC25 cells showed several lines of apoptotic manifestation such as nuclear condensations, DNA fragmentation, reduction of MMP and proteasome activity, the increase of Bax and the decrease of Bcl-2, decrease of DNA content, the release of cytochrome c into cytosol, translocation of AIF and DFF40 (CAD) onto nuclei, and activation of caspase-9, caspase-7, caspase-3, PARP and DFF45 (ICAD) whereas each single treated SCC25 cells did not show these patterns. Although the single treatment of $25{\mu}M$ HS-1200 and $4{\mu}g/ml$ cisplatin for 24 h did not induce apoptosis, the co-treatment of these reagents prominently induced apoptosis. Therefore our data provide the possibility that the combination therapy with HS-1200 and cisplatin could be considered as a novel therapeutic strategy for human squamous cell carcinoma.

• Radiation Oncology Journal
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• v.4 no.2
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• pp.89-97
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• 1986

Using as assay for jejunal crypt stem cell survival, dose-response curves for the reproductive capacity of crypt stem cells of mouse jejunum exposed to multifractionated gamma-ray irradiation (single, 2, 3, 4, 5, 8, 10, 12, and 16 fractions) were analyzed and single-dose survival curve of these cells was constructed. The following conclusion were drawn: 1) Survival curves for higher numbers of dose fractions were displaced to higher dose, and characterized by increasingly shallower slopes. 2) The single-dose survival curve had broad shoulder, Dq=460 cGy, remaining near-exponential over initial dose range 0 to 300 cGy, with initial slope 1Do=474 cGy. 3) At fractionated dose En the range of 180 to 450 cGy, the average recovered dose per fraction interval was approximately $50\%$ of the dose per fraction. 4) The value of $\alpha/\beta$ ratio by using of linear regression analysis for the reciprocal dose plots was 8.3 Gy which lied in the range of 6-14 Gy for early-reacting tissues. 5) The linear-quadratic model for dose-response formula offers valid approximations for at 1 doses to be used in radiotherapy, only two parameters to be determined, and considerable convenience in practical applications.

• Biomedical Science Letters
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• v.26 no.4
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• pp.344-350
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• 2020

Asthma is a chronic disease and occurs in airway in the lung. The cause of the disease has not been identified, it is assumed that both genetic and environmental risk factors play an important role in the development of asthma. Interleukin (IL)-12 is a cytokine regulating T-cell and NK cell. In this study, we analyzed the genetic polymorphisms of IL-12 receptor genes (IL-12Rβ1 and IL-12Rβ2) in asthma patients and normal individuals in a Korean population. We analyzed single nucleotide polymorphisms (SNPs) in IL-12Rβ1 and IL-12Rβ2 using the genotype data of 193 asthma cases and 3,228 healthy controls from the Korea Association REsource for their correlation with asthma case. IL-12Rβ1 and IL-12Rβ2 genes showed statistically significant polymorphism association with asthma case. As a results, 16 SNPs from IL-12Rβ1 and IL-12Rβ2 genes showed statistically significant association with asthma. Among them, rs375947 SNP in IL-12Rβ1 showed the greatest statistical correlation with asthma (P-value = 0.028, Odds Ratio = 1.27, 95% Confidence Interval = 1.03~1.57). The groups with minor allele of IL-12Rβ1 and IL-12Rβ2 showed increased risk of asthma. The genotype-based mRNA expression analysis showed that the group of minor allele of IL-12Rβ1 showed decreased mRNA expression. Decreased IL-12Rβ1 expression causes decreased IL-12 signaling, and this affects developing asthma. In conclusion, the SNPs in IL-12Rβ1 and IL-12Rβ2 may contribute to development of asthma in a Korean population.