Hyeong Joon Kim

Analysis of Cariogenic Bacteria in Saliva of Cancer Patients

This study examined salivary flow and salivary pH and the prevalence and levels of cariogenic bacteria in the saliva of oncological patients and healthy controls. Quantitative real-time polymerase chain reaction was used to assess the levels of microbes including Streptococcus mutans, Streptococcus sobrinus, Lactobacillus salivarius, and Lactobacillus acidophilus in the saliva of 41 patients with a solid tumor (SO), 30 patients with a hematologic malignancy (HE), and 40 healthy controls. Salivary flow and pH were lower in oncological patients than in controls. The frequencies of all four cariogenic bacteria were highest in the SO group. S. mutans and L. salivarius were the most commonly detected in all three study groups. Mean numbers of S. sobrinus and L. salivarius in the SO group were significantly higher than in controls (p<0.05). There were no significant differences between patients and controls with respect to mean numbers of S. mutans and L. acidophilus in saliva. However, the proportions of S. mutans, S. sobrinus, and L. salivarius versus total bacteria in the SO group were significantly higher than in controls. Within patients, both mean numbers and the proportions of S. mutans and S. sobrinus were significantly different (p<0.05). In summary, significant differences were found in salivary pH values and the levels of S. mutans, S. sobrinus, and L. salivarius between SO patients and healthy controls.

A phase 4 study of nilotinib in Korean patients with Philadelphia chromosome‐positive chronic myeloid leukemia in chronic phase: ENESTKorea

Although nilotinib has improved efficacy compared to imatinib, suboptimal response and intolerable adverse events (AEs) limit its effectiveness in many patients with chronic myeloid leukemia in chronic phase (CML‐CP). We investigated the 2‐year efficacy and safety of nilotinib and their relationships with plasma nilotinib concentrations (PNCs). In this open‐label, multi‐institutional phase 4 study, 110 Philadelphia chromosome‐positive CML‐CP patients were treated with nilotinib at a starting dose of 300 mg twice daily. Molecular responses (MRs) and AEs were monitored for up to 24 months. The 24‐month cumulative MR4.5 rate was evaluated as the primary endpoint. Plasma samples were collected from 94 patients to determine PNCs, and the per‐patient mean was used to categorize them into four mean PNC (MPNC) groups. Cumulative MR rates and safety were compared between groups. With a median follow‐up of 22.2 months, the 24‐month cumulative MR4.5 rate was 56.2% (95% confidence interval, 44.0%–8.3%), and the median time to MR4.5 was 23.3 months. There were no significant differences in the cumulative rates of major molecular response, MR4, and MR4.5 between MPNC groups. One patient died due to acute viral hepatitis, and two developed hematological or cytogenetic relapse, while no progression to accelerated or blast phase was observed. Safety results were consistent with previous studies with no new safety signal identified. Across the MPNC groups, there was no significant linear trend in the frequency of AEs. Nilotinib is highly effective for the treatment of CML‐CP with manageable AEs. The measurement of PNC has no predictive value for patient outcomes and is thus not found to be clinically useful. This study is registered with clinicaltrials.gov, Number NCT03332511.

Cytogenetic and Molecular Failure at 12 Months will be the Optimal Time Point for BCR-ABL1 Tyrosine Kinase Domain Mutation Analysis in Patients with Chronic Myeloid Leukemia: The Analysis Based on 2013 European LeukemiaNet Recommendation

Abstract: CML-020 Cytogenetic and Molecular Failure at 12 Months will be the Optimal Time Point for BCR-ABL1 Tyrosine Kinase Domain Mutation Analysis in Patients with Chronic Myeloid Leukemia: The Analysis Based on 2013 European LeukemiaNet Recommendation Hee-Je Kim, Hea-Lyun Yoo, Won-Sik Lee, Hyeong-Joon Kim, Jee Hyun Kong, Yunsuk Choi, Young Rok Do, Jae-Yong Kwak, Sukjoong Oh, Sung Hyun Kim, Jeong-A. Kim, Dae Young Zang, Yeung-Chul Mun, Young-Woong Won, Sung-Eun Lee, Dong-Wook Kim Department of Hematology, Seoul St. Mary’s Hospital, The Catholic University of Korea; Department of Internal Medicine, Inje University College of Medicine, Inje University Busan Paik Hospital; Department of Hematology-Oncology, Chonnam National University Hwasun Hospital; Department of Hematology-Oncology, Wonju College of Medicine, Yonsei University; Department of Hematology, University of Ulsan College of Medicine, Ulsan University Hospital; Division of Hematology-Oncology, Keimyung University, School of Medicine, Keimyung University Hospital; Division of Hematology-Oncology, Chonbuk National University Medical School, Chonbuk National University Hospital; Division of Hematology-Oncology, Department of Internal Medicine, School of Medicine, Sungkyunkwan University, Kangbuk Samsung Hospital; Department of Internal Medicine, DongA University College of Medicine, Dong-A University Hospital; Department of Hematology, The Catholic University of Korea, St. Vincent’s Hospital; Department of Internal Medicine, Hallym University College of Medicine, Hallym University Hospital; Department of Hematology, School of Medicine, Ewha Womans University, Ehwa Womans University Hospital; Division of Hematology and Oncology, Department of Internal Medicine, Hanyang Univerysity College of Medicine, Hanyang University Guri Hospital CML-020 Cytogenetic and Molecular Failure at 12 Months will be the Optimal Time Point for BCR-ABL1 Tyrosine Kinase Domain Mutation Analysis in Patients with Chronic Myeloid Leukemia: The Analysis Based on 2013 European LeukemiaNet Recommendation Hee-Je Kim, Hea-Lyun Yoo, Won-Sik Lee, Hyeong-Joon Kim, Jee Hyun Kong, Yunsuk Choi, Young Rok Do, Jae-Yong Kwak, Sukjoong Oh, Sung Hyun Kim, Jeong-A. Kim, Dae Young Zang, Yeung-Chul Mun, Young-Woong Won, Sung-Eun Lee, Dong-Wook Kim Department of Hematology, Seoul St. Mary’s Hospital, The Catholic University of Korea; Department of Internal Medicine, Inje University College of Medicine, Inje University Busan Paik Hospital; Department of Hematology-Oncology, Chonnam National University Hwasun Hospital; Department of Hematology-Oncology, Wonju College of Medicine, Yonsei University; Department of Hematology, University of Ulsan College of Medicine, Ulsan University Hospital; Division of Hematology-Oncology, Keimyung University, School of Medicine, Keimyung University Hospital; Division of Hematology-Oncology, Chonbuk National University Medical School, Chonbuk National University Hospital; Division of Hematology-Oncology, Department of Internal Medicine, School of Medicine, Sungkyunkwan University, Kangbuk Samsung Hospital; Department of Internal Medicine, DongA University College of Medicine, Dong-A University Hospital; Department of Hematology, The Catholic University of Korea, St. Vincent’s Hospital; Department of Internal Medicine, Hallym University College of Medicine, Hallym University Hospital; Department of Hematology, School of Medicine, Ewha Womans University, Ehwa Womans University Hospital; Division of Hematology and Oncology, Department of Internal Medicine, Hanyang Univerysity College of Medicine, Hanyang University Guri Hospital

Improvement in the Device Characteristics of Tin Oxide Thin-film Transistors by Adopting Ultralow-Pressure Sputtering

Recently, amorphous InGaZnO thin film transistors (TFTs) have been intensively studied because they exhibit large mobility (>10cm/Vs) and relatively good stability despite their amorphous phase. Before InGaZnO TFTs as a backplane device are adopted into the flat panel displays such as active matrix liquid crystal display or organic light-emitting diodes display in the mass-production, there are several issues to be addressed: first, the most promising candidates are based on systems including indium (over 40 % for ternary system) to achieve high channel mobility. Nevertheless, the estimated amount of indium in the earth’s crust is only 6000 tons, and its depletion is becoming a serious problem. Second, the accurate and repeatable control of such a complex material in mass production stage is not an easy task. Therefore, solutions avoiding the use of indium and finding the novel oxide system with binary oxide compositions are preferable. Here, tin-based oxide semiconductor as a channel layer of TFTs was revisited. Because tin ion [ex. Sn: 4d5s] has an orbital similarity of indium ion [In: 4d5s], the high mobility can be attainable. So far, tin oxide has been used as the main component of a transparent conductive oxide such as ITO. However, its application to active channel of TFTs was limited due to the difficulty in controlling the net electron density (Nd) (<10 cm). In this letter, we report on the fabrication of TFTs with the SnOx channel layer by using ultralow-pressure, rf magnetron sputtering (ULPS) with a sputtering pressure of less than 1.3 x 10 Pa and a substrate temperature as low as 120 C. The Nd was generally smaller in the ULPS films than in the conventional sputtering pressure (CSP) films at all O2 ratios. This is crucial to achieve the desired high on/off current (ION/OFF) ratio in the TFT devices. The Nd of the CSP films could not be decreased to lower than 10 cm even at the highest O2 % ratio, whereas it was already of the order of 10 cm for the ULPS film even at the O2 % ratio of 15%. These significant decrease in the Nd from 10 to 10 cm, which resulted in the transistor behavior having reasonable mobility and ION/OFF ratio. This was attributed to the formation of more stoichiometric SnO2 phase with the ULPS process, as shown in Fig. 1. Figure 2(a) and (b) shows the representative output characteristics for TFTs with the CSP SnOx film and ULPS SnOx film, respectively. It can be seen that the drain current (IDS) of CSP SnOx TFT is monotonously increased with increasing drain voltage (VDS) as shown in Fig. 2(a). However, there is no saturation of drain current, i.e. pinch-off phenomenon, suggesting that the channel layer near drain junction is not fully depleted presumably due to high conductivity of the channel layer itself. On the other hand, the ULPS SnOx TFT exhibited the clear pinch-off and IDS saturation, indicating that the electron transportation in active channels is totally controlled by the gate and drain voltages. Figure 2(c) and (d) show the transfer characteristics of CSP SnOx and ULPS SnOxTFT, respectively. Indeed, the CSP SnOx TFT exhibit the very high off-current of 5x10A at VGS = -40V, which is consistent with the speculation of high conductivity of active channel layer. However, the ULPS SnOx TFT exhibited the reasonable VTH of 1.2 V and μFE of 4.0 cm/Vs (in the linear region) as well as the low off-state current of 3x10 A and ION/OFF ratio of 1.4x10 (Fig.2(d)). In summary, we proposed the possibility of fabricating the SnOx TFTs by adopting ultralow-pressure sputtering. The Nd of SnOx films can be controlled by decreasing sputtering pressure during thin film growth. Thus, the ULPS SnOx TFTs are expected to find the important application in the back-planes of new emerging flexible and/or transparent display devices.

Chemical Vapor Deposition of Silica Nanowires using Heteroleptic Bis(ethylmethylamino)silane Precursor

One-dimentional nanomaterials have attracted great attention due to their exceptional properties since the discovery of carbon nanotubes by S. Iijima in 1991 [1]. Among 1D nanomaterials, silica nanowires have been a subject of intense study in view of their unique properties like blue light emission and easy surface functionalization [2, 3]. In the present study, silica nanowires were synthesized by employing inherent directionality of chemical vapor reaction between heteroleptic bis(ethylmethylamino)silane ((H2Si[N(C2H5)(CH3)]2) precursor and water without a metal catalyst at room temperature. Figs. 1A and 1B show the molecular structures of precursors, bis(ethylmethylamino)silane and tetrakis(ethylmethylamino)silane respectively. The conceptual scheme used here is that the difference in the oxidation reactivities between Si-H and Si-N groups with water leads the formation of linear shaped products. Fig. 1C shows the cross-section SEM image of representative silica nanowires produced using bis(ethylmethylamino)silane precursor. When tetrakis(ethylmethylamino)silane was used instead of bis(ethylmethylamino)silane, as shown in Fig. 1D, twodimensional film growth with limited nucleation is observed. Figs. 2A, 2B, and 2C show crystallinity and composition of synthesized silica nanowires, including that they are in an amorphous state with Si:O elements of a ratio of ~1:2. Fig. 2D presents the FTIR spectrum of the as-grown silica nanowires on the Si substrates. An absorption band was detected between 837 and 885 cm, which is assigned to the bending modes of H-SiO. The existence of this H-SiO peak and the absence of the Si-N peak indicate that water preferentially replaces the amine groups bonded with Si.