Jaeseok Kim

Bio: Jaeseok Kim is an academic researcher from Yonsei University. The author has contributed to research in topics: MIMO & Encoder. The author has an hindex of 19, co-authored 283 publications receiving 1717 citations.

Immunopathogenesis and treatment of cytokine storm in COVID-19.

Abstract: Severe coronavirus disease 2019 (COVID-19) is characterized by systemic hyper-inflammation, acute respiratory distress syndrome, and multiple organ failure. Cytokine storm refers to a set of clinical conditions caused by excessive immune reactions and has been recognized as a leading cause of severe COVID-19. While comparisons have been made between COVID-19 cytokine storm and other kinds of cytokine storm such as hemophagocytic lymphohistiocytosis and cytokine release syndrome, the pathogenesis of cytokine storm has not been clearly elucidated yet. Recent studies have shown that impaired response of type-1 IFNs in early stage of COVID-19 infection played a major role in the development of cytokine storm, and various cytokines such as IL-6 and IL-1 were involved in severe COVID-19. Furthermore, many clinical evidences have indicated the importance of anti-inflammatory therapy in severe COVID-19. Several approaches are currently being used to treat the observed cytokine storm associated with COVID-19, and expectations are especially high for new cytokine-targeted therapies, such as tocilizumab, anakinra, and baricitinib. Although a number of studies have been conducted on anti-inflammatory treatments for severe COVID-19, no specific recommendations have been made on which drugs should be used for which patients and when. In this review, we provide an overview of cytokine storm in COVID-19 and treatments currently being used to address it. In addition, we discuss the potential therapeutic role of extracorporeal cytokine removal to treat the cytokine storm associated with COVID-19.

Motion compensated frame interpolation by new block-based motion estimation algorithm

Abstract: In this paper, a motion compensated frame interpolation (MCI) algorithm adapting new block-based motion estimation (BME), which is overlapped block-based motion estimation (OBME), is proposed for frame rate up-conversion (FRC). Unlike conventional BME algorithms, where a video frame is divided into many non-overlapping square blocks of pixels, the proposed BME is executed using an overlapped matching block in order to get more accurate motion trajectory. To reduce computational complexity caused by the OBME, a sub-sampled pixel block is used for the OBME. The proposed OBME is executed with the various overlapped blocks that have different block sizes and sub-sampling ratios. In this paper, instead of mean absolute difference (MAD) used for general BME, a modified MAD is applied for the OBME. The MAD proposed is weighted using the magnitude of MV that corresponds to the estimating position. From the simulation results, the proposed methods show better performance in estimating "true motion" and reducing blocking artifacts with less complexity in calculation compared to a conventional method.

New efficient FFT algorithm and pipeline implementation results for OFDM/DMT applications

Abstract: In this paper, we propose a new efficient FFT algorithm for OFDM/DMT applications and present its pipeline implementation results. Since the proposed algorithm is based on the radix-4 butterfly unit, the processing rate can be twice as fast as that based on the radix-23 algorithm. Also, its implementation is more area-efficient than the implementation from conventional radix-4 algorithm due to reduced number of nontrivial multipliers like using the radix-2/sup 3/ algorithm. In order to compare the proposed algorithm with the conventional radix-4 algorithm, the 64-point MDC pipelined FFT processor based on the proposed algorithm was implemented. After the logic synthesis using 0.35 /spl mu/m CMOS technology, the logic gate count for the processor with the proposed algorithm is only about 70% of that for the processor with the conventional radix-4 algorithm. Since the proposed algorithm can achieve higher processing rate and better efficiency than the conventional algorithm, it is very suitable for the OFDM/DMT applications such as the WLAN, DAB/DVB, and ADSL/VDSL systems.

Single-agent Gemcitabine in the Treatment of Advanced Biliary Tract Cancers: a Phase II Study

Abstract: Objective: Patients with advanced biliary tract cancers have a dismal prognosis. The aim of this study was to evaluate the efficacy and safety of gemcitabine as a single agent in the treatment of patients with unresectable biliary tract cancers. Methods: From May 2002 to April 2004, 23 chemotherapy-naive patients with locally advanced or metastatic biliary tract adenocarcinomas were enrolled. The median age was 59 years (range 37-76). Fifteen patients (65.2%) had cholangiocarcinomas and eight (34.8%) had gallbladder adenocarcinomas. Patients received gemcitabine 1000 mg/m 2 over 60 min once a week for 2 weeks followed by a week off therapy. Treatment was discontinued when unacceptable toxicities occurred or there was evidence of disease progression. Results: A total of 110 cycles ofchemotherapy were performed with a median offour cycles (range 1-10). The median follow-up was 13.4 months. Among the 23 patients, six (26.1%) had a partial response, eight (34.8%) had stable disease and nine (39.1%) had disease progression despite treatment. The overall response rate was 26.1% [95% confidence interval (Cl) 22.08-30.12]. The median time to disease progression was 8.1 months (95% Cl 3.33-12.87) and the median overall survival was 13.1 months (95% Cl 1.64-24.56). Toxicities were generally mild and treatment was well tolerated. Of the 23 patients, one patient experienced a grade 3-4 neutropenia and one a grade 3-4 thrombocytopenia; however, no cases of febrile neutropenia or treatment-related deaths were noted. Conclusion: In this phase II trial, therapy with gemcitabine was well tolerated and clinically active in patients with locally advanced or metastatic biliary tract cancers.

Natural hdr image tone mapping based on retinex

Abstract: In this paper, new k factor decision method and highlight compression operator are proposed to enhance the appearance and naturalness of rendered High Dynamic Range (HDR) images. The retinex algorithm is one of the outstanding local operators, which well preserves local contrast in highlights. However, the retinex algorithm gives a worse overall appearance and undistinguishable dark area contrast than global operators or other local operators in some cases. The most prominent improvement of the proposed method is that the decision method of the k factor, which is one of the parameters in retinex algorithm, is proposed by using the dynamic range in images. The proposed parameter decision method enhances the overall quality and preference of the image and solves any parameter setting problems. Also, dark area details become more distinguishable by the highlight compression operator. According to the results of many HDR image experiments, the proposed method shows better rendering in terms of naturalness and dark area details than the previous tone-mapping algorithm.1.

Harrison's Principles of Internal Medicine

Abstract: The 11th edition of Harrison's Principles of Internal Medicine welcomes Anthony Fauci to its editorial staff, in addition to more than 85 new contributors. While the organization of the book is similar to previous editions, major emphasis has been placed on disorders that affect multiple organ systems. Important advances in genetics, immunology, and oncology are emphasized. Many chapters of the book have been rewritten and describe major advances in internal medicine. Subjects that received only a paragraph or two of attention in previous editions are now covered in entire chapters. Among the chapters that have been extensively revised are the chapters on infections in the compromised host, on skin rashes in infections, on many of the viral infections, including cytomegalovirus and Epstein-Barr virus, on sexually transmitted diseases, on diabetes mellitus, on disorders of bone and mineral metabolism, and on lymphadenopathy and splenomegaly. The major revisions in these chapters and many

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

Abstract: Summary Background Since December, 2019, Wuhan, China, has experienced an outbreak of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Epidemiological and clinical characteristics of patients with COVID-19 have been reported but risk factors for mortality and a detailed clinical course of illness, including viral shedding, have not been well described. Methods In this retrospective, multicentre cohort study, we included all adult inpatients (≥18 years old) with laboratory-confirmed COVID-19 from Jinyintan Hospital and Wuhan Pulmonary Hospital (Wuhan, China) who had been discharged or had died by Jan 31, 2020. Demographic, clinical, treatment, and laboratory data, including serial samples for viral RNA detection, were extracted from electronic medical records and compared between survivors and non-survivors. We used univariable and multivariable logistic regression methods to explore the risk factors associated with in-hospital death. Findings 191 patients (135 from Jinyintan Hospital and 56 from Wuhan Pulmonary Hospital) were included in this study, of whom 137 were discharged and 54 died in hospital. 91 (48%) patients had a comorbidity, with hypertension being the most common (58 [30%] patients), followed by diabetes (36 [19%] patients) and coronary heart disease (15 [8%] patients). Multivariable regression showed increasing odds of in-hospital death associated with older age (odds ratio 1·10, 95% CI 1·03–1·17, per year increase; p=0·0043), higher Sequential Organ Failure Assessment (SOFA) score (5·65, 2·61–12·23; p Interpretation The potential risk factors of older age, high SOFA score, and d-dimer greater than 1 μg/mL could help clinicians to identify patients with poor prognosis at an early stage. Prolonged viral shedding provides the rationale for a strategy of isolation of infected patients and optimal antiviral interventions in the future. Funding Chinese Academy of Medical Sciences Innovation Fund for Medical Sciences; National Science Grant for Distinguished Young Scholars; National Key Research and Development Program of China; The Beijing Science and Technology Project; and Major Projects of National Science and Technology on New Drug Creation and Development.

On the capacity of a cellular CDMA system

Abstract: It is shown that, particularly for terrestrial cellular telephony, the interference-suppression feature of CDMA (code division multiple access) can result in a many-fold increase in capacity over analog and even over competing digital techniques. A single-cell system, such as a hubbed satellite network, is addressed, and the basic expression for capacity is developed. The corresponding expressions for a multiple-cell system are derived. and the distribution on the number of users supportable per cell is determined. It is concluded that properly augmented and power-controlled multiple-cell CDMA promises a quantum increase in current cellular capacity. >

Impact of Protein Kinase PKR in Cell Biology: from Antiviral to Antiproliferative Action

Abstract: The double-stranded RNA-dependent protein kinase PKR is a critical mediator of the antiproliferative and antiviral effects exerted by interferons. Not only is PKR an effector molecule on the cellular response to double-stranded RNA, but it also integrates signals in response to Toll-like receptor activation, growth factors, and diverse cellular stresses. In this review, we provide a detailed picture on how signaling downstream of PKR unfolds and what are the ultimate consequences for the cell fate. PKR activation affects both transcription and translation. PKR phosphorylation of the alpha subunit of eukaryotic initiation factor 2 results in a blockade on translation initiation. However, PKR cannot avoid the translation of some cellular and viral mRNAs bearing special features in their 5′ untranslated regions. In addition, PKR affects diverse transcriptional factors such as interferon regulatory factor 1, STATs, p53, activating transcription factor 3, and NF-κB. In particular, how PKR triggers a cascade of events involving IKK phosphorylation of IκB and NF-κB nuclear translocation has been intensively studied. At the cellular and organism levels PKR exerts antiproliferative effects, and it is a key antiviral agent. A point of convergence in both effects is that PKR activation results in apoptosis induction. The extent and strength of the antiviral action of PKR are clearly understood by the findings that unrelated viral proteins of animal viruses have evolved to inhibit PKR action by using diverse strategies. The case for the pathological consequences of the antiproliferative action of PKR is less understood, but therapeutic strategies aimed at targeting PKR are beginning to offer promising results.