• Journal of Korea Water Resources Association
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• v.57 no.5
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• pp.333-346
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• 2024

High-resolution medium-range streamflow prediction is crucial for sustainable water quality and aquatic ecosystem management. For reliable medium-range streamflow predictions, it is necessary to understand the characteristics of forcings and to effectively utilize weather forecast data with low spatio-temporal resolutions. In this study, we presented a comparative analysis of medium-range streamflow predictions using the distributed hydrological model, WRF-Hydro, and the numerical weather forecast Global Data Assimilation and Prediction System (GDAPS) in the Geumho River basin, Korea. Multiple forcings, ground observations (AWS&ASOS), numerical weather forecast (GDAPS), and Global Land Data Assimilation System (GLDAS), were ingested to investigate the performance of streamflow predictions with highresolution WRF-Hydro configuration. In terms of the mean areal accumulated rainfall, GDAPS was overestimated by 36% to 234%, and GLDAS reanalysis data were overestimated by 80% to 153% compared to AWS&ASOS. The performance of streamflow predictions using AWS&ASOS resulted in KGE and NSE values of 0.6 or higher at the Kangchang station. Meanwhile, GDAPS-based streamflow predictions showed high variability, with KGE values ranging from 0.871 to -0.131 depending on the rainfall events. Although the peak flow error of GDAPS was larger or similar to that of GLDAS, the peak flow timing error of GDAPS was smaller than that of GLDAS. The average timing errors of AWS&ASOS, GDAPS, and GLDAS were 3.7 hours, 8.4 hours, and 70.1 hours, respectively. Medium-range streamflow predictions using GDAPS and high-resolution WRF-Hydro may provide useful information for water resources management especially in terms of occurrence and timing of peak flow albeit high uncertainty in flood magnitude.

• The Journal of Korean Academy of Prosthodontics
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• v.40 no.1
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• pp.1-17
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• 2002

The purpose of this study is to examine the possibility of thermal injury to bone tissues during an implant site preparation under the same condition as a typical clinical practice of $Br{\aa}nemark$ implant system. All the burs for $Br{\aa}nemark$ implant system were studied except the round bur The experiments involved 880 drilling cases : 50 cases for each of the 5 steps of NP, 5 steps of RP, and 7 steps of WP, all including srew tap, and 30 cases of 2mm twist drill. For precision drilling, a precision handpiece restraining system was developed (Eungyong Machinery Co., Korea). The system kept the drill parallel to the drilling path and allowed horizontal adjustment of the drill with as little as $1{\mu}m$ increment. The thermocouple insertion hole. that is 0.9mm in diameter and 8mm in depth, was prepared 0.2mm away from the tapping bur the last drilling step. The temperatures due to countersink, pilot drill, and other drills were measured at the surface of the bone, at the depths of 4mm and 8mm respectively. Countersink drilling temperature was measured by attaching the tip of a thermocouple at the rim of the countersink. To assure temperature measurement at the desired depths, 'bent-thermocouples' with their tips of 4 and 8mm bent at $120^{\circ}$ were used. The profiles of temperature variation were recorded continuously at one second interval using a thermometer with memory function (Fluke Co. U.S.A.) and 0.7mm thermocouples (Omega Co., U.S.A.). To simulate typical clinical conditions, 35mm square samples of bovine scapular bone were utilized. The samples were approximately 20mm thick with the cortical thickness on the drilling side ranging from 1 to 2mm. A sample was placed in a container of saline solution so that its lower half is submerged into the solution and the upper half exposed to the room air, which averaged $24.9^{\circ}C$. The temperature of the saline solution was maintained at $36.5^{\circ}C$ using an electric heater (J. O Tech Co., Korea). This experimental condition was similar to that of a patient s opened mouth. The study revealed that a 2mm twist drill required greatest attention. As a guide drill, a twist drill is required to bore through a 'virgin bone,' rather than merely enlarging an already drilled hole as is the case with other drills. This typically generates greater amount of heat. Furthermore, one tends to apply a greater pressure to overcome drilling difficulty, thus producing even greater amount heat. 150 experiments were conducted for 2mm twist drill. For 140 cases, drill pressure of 750g was sufficient, and 10 cases required additional 500 or 100g of drilling pressure. In case of the former. 3 of the 140 cases produced the temperature greater than $47^{\circ}C$, the threshold temperature of degeneration of bone tissue (1983. Eriksson et al.) which is also the reference temperature in this study. In each of the 10 cases requiring extra pressure, the temperature exceeded the reference temperature. More significantly, a surge of heat was observed in each of these cases This observations led to addtional 20 drilling experiments on dense bones. For 10 of these cases, the pressure of 1,250g was applied. For the other 10, 1.750g were applied. In each of these cases, it was also observed that the temperature rose abruptly far above the thresh old temperature of $47^{\circ}C$, sometimes even to 70 or $80^{\circ}C$. It was also observed that the increased drilling pressure influenced the shortening of drilling time more than the rise of drilling temperature. This suggests the desirability of clinically reconsidering application of extra pressures to prevent possible injury to bone tissues. An analysis of these two extra pressure groups of 1,250g and 1,750g revealed that the t-statistics for reduced amount of drilling time due to extra pressure and increased peak temperature due to the same were 10.80 and 2.08 respectively suggesting that drilling time was more influenced than temperature. All the subsequent drillings after the drilling with a 2mm twist drill did not produce excessive heat, i.e. the heat generation is at the same or below the body temperature level. Some of screw tap, pilot, and countersink showed negative correlation coefficients between the generated heat and the drilling time. indicating the more the drilling time, the lower the temperature. The study also revealed that the drilling time was increased as a function of frequency of the use of the drill. Under the drilling pressure of 750g, it was revealed that the drilling time for an old twist drill that has already drilled 40 times was 4.5 times longer than a new drill The measurement was taken for the first 10 drillings of a new drill and 10 drillings of an old drill that has already been used for 40 drillings. 'Test Statistics' of small samples t-test was 3.49, confirming that the used twist drills require longer drilling time than new ones. On the other hand, it was revealed that there was no significant difference in drilling temperature between the new drill and the old twist drill. Finally, the following conclusions were reached from this study : 1 Used drilling bur causes almost no change in drilling temperature but increase in drilling time through 50 drillings under the manufacturer-recommended cooling conditions and the drilling pressure of 750g. 2. The heat that is generated through drilling mattered only in the case of 2mm twist drills, the first drill to be used in bone drilling process for all the other drills there is no significant problem. 3. If the drilling pressure is increased when a 2mm twist drill reaches a dense bone, the temperature rises abruptly even under the manufacturer-recommended cooling conditions. 4. Drilling heat was the highest at the final moment of the drilling process.

• Journal of Food Hygiene and Safety
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• v.34 no.3
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• pp.227-234
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• 2019

An analytical method was developed for the determination of oxytetracycline in agricultural products using the QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method by liquid chromatography-tandem mass spectrometry (LC-MS/MS). After the samples were extracted with methanol, the extracts were adjusted to pH 4 by formic acid and sodium chloride was added to remove water. Dispersive solid phase extraction (d-SPE) cleanup was carried out using $MgSO_4$ (anhydrous magnesium sulfate), PSA (primary secondary amine), $C_{18}$ (octadecyl) and GCB (graphitized carbon black). The analytes were quantified and confirmed with LC-MS/MS using ESI (electrospray ionization) in positive ion MRM (multiple reaction monitoring) mode. The matrix-matched calibration curves were constructed using six levels ($0.001{\sim}0.25{\mu}g/mL$) and coefficient of determination ($r^2$) was above 0.99. Recovery results at three concentrations (LOQ, $10{\times}LOQ$, and $50{\times}LOQ$, n=5) were from 80.0 to 108.2% with relative standard deviations (RSDs) less than of 11.4%. For inter-laboratory validation, the average recovery was in the range of 83.5~103.2% and the coefficient of variation (CV) was below 14.1%. All results satisfied the criteria ranges requested in the Codex guidelines (CAC/GL 40-1993, 2003) and the Food Safety Evaluation Department guidelines (2016). The proposed analytical method was accurate, effective and sensitive for oxytetracycline determination in agricultural commodities. This study could be useful for safety management of oxytetracycline residues in agricultural products.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.216-226
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• 1983

Genetic studies on the $F_2$ generation of a set of half diallel crosses involving six cowpea varieties were conducted. by the randomized block design with three replications to determine combining ability, gene action and the relationships between parents and their $F_2$ hybrids. The 12 agronomic characters namely, days to flowering, days from flowering to maturity, days to maturity, diameter of stem, length of internode, number of branches per plant, length of pod, number of pods per plant, number of grains per pod, number of grains per plant, 100 grain weight and grain weight per plot were observed, and the $F_2$ generation of this diallel set of crosses was analysed for each character according to the method by Jinks and Hayman. The results obtained are summarized as follows: 1. Vr-Wr graphical analyses; The following seven characters, days to flowering, number of branches per plant, length of pod, number of pods per plant, number of grains per plant, 100 grain weight and grain weight per plot appeared to be partially dominant, and over dominance was found for days from flowering to maturity, days to maturity, length of internode and number of grains per pod. But diameter of stem indicated partial dominance near complete dominance. 2. Estimates of genetic variance components; In the degree of dominance,. eight characters, that is, days to flowering, days from flowering to maturity, days to maturity, length of internode, number of pods per plant, number of grains per pod, number of grains per plant and grain weight per plot were expressed larger than 1. And the characters, days from flowering to maturity, number of branches per plant and number of grains per plant as the degree of mean dominance ($H_1$/D) were found to be negative value over other characters. On the other hand, apprent asymmetry of dominance-recessive allele ($H_2$ /$4H_1$) produced comparatively estimates with lower value on days from flowering to maturity, length of internode, number of branches per plant and number of grains per pod. 3. Analyses of combining ability; Mean square value of GCA(general combining ability) appeared to be more important than those of SCA (specific combining ability) for most characters, and among them, grain weight per plot showed the highest mean square value in GCA and SCA. 4. Effect of combining ability; Variety 178 was expressed as the highest GCA effects in five characters (days to flowering days to maturity, number of pods per plant, number of grains per plant and grain weight per plot). SCA effects were differed from parents, characters and crosses, but crosses between TVu 1857 $\times$ TVu 2885 and TVu 2702 $\times$ J78 were shown to be highly with SCA effects on yield.

• Journal of the Korean Geographical Society
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• v.31 no.3
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• pp.447-468
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• 1996

The peat layer was deposited on the abandoned channel of incised meander of River Banbyuncheon with 7 meter thickness on Youngyang basin. The late Quaternary environmental change on the study area was discussed based on pollen anaalysis and radiocarbon-dating from this peat. The swamp which was caused to sediment the peat, was produced by which the fan debris from the adjacent slope damed the waterflow on the abandoned channel. The peat layer contains continuous vegetational history from 60,000y.B.P. to Recent. The peat deposit was divided into two layers by the organic thin sand horizon, which was sedimented at one time and made unconformity between the lower decomposed compact peat layers and the upper fresh fiberous peat layer. As the result of the pollen analysis, both peat layers from the two boring sites, Profile YY1 and Profile YY2 were divided into five Pollenzones(Pollenzone I, II, III, IV and V) and 12 Subzones which were mainly corresponded by the AP (Arboreal Pollen)-Dominance. The two profiles have some differences on the sedimentary facies and on the pollen composition as well. Therefore these were in common with the Pollenone III, however the Pollenzone I and II existed only on the Profile YY1 and the Pollenzone IV and V existed only on the Profile YY2. The lower layer containing the Pollenzone I, II and III revealed vegetational records of Pleistocene, which was characterized as tundra-like landscape and thin forested landscapes. It represented the NAP (Non-Arboreal Pollen)-period with a plenty of Artemisia sp., Sanguisorba sp., Umbelliferae, Gramineae and Cyperaceae. However a relatively high proportion of the boreal trees with Picea sp., Pinus sp. and Betula sp. as AP was observed in the lower layer. The upper layer contained the Pollenzone IVb and V and vegetational history in Holocene which was characterized by thick forested landscape with rich tree pollen. It represented AP-period with plenty of Pinus sp. and Quercus sp. as temperate trees. The temperature fluctuation supposed from the vegetational records is as follows; the Pollenzone I(Betula-Dominance, about 57,000y.B.P.) represents relatively cold period. The Pollenzone II(EMW-Domi-nance, 57,000-43,000y.B.P.)represents relatively warm period. This period is supposed to be Interstadial, the transi-tional stage from Alt- to Mittel Wurm. The Pollenzone III(Butula-, Pinus- and Picea-Dominace in turns, 43,000-15,000y.B.P.) reproesents cold period which had been built from Mittel-to Jung Wurm. Especially the Subzone IIId represents the coldest period throughout the Pollenzone III. It is corresponds to Wurm Glacial Maximu. It is supposed that the mean temperature in July of this period was coller about 10${^\circ}$C than present. The Pollenzone IV and V represent the vegetational history of Holocene. Tilia, Quercus and Pinus were dominant in turns during this period. Subzone IVb and Pollenzone I and II at east coastal plain of Korean penninsula reported by JO(1979).

• Tuberculosis and Respiratory Diseases
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• v.59 no.5
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• pp.522-529
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• 2005

Background : Several national societies have published guidelines for empirical antimicrobial therapy in patients with severe community-acquired pneumonia (SCAP). This study investigated the etiologies of SCAP in the Asan Medical Center and assessed the relationship between the initial empirical antimicrobial regimen and 30 day mortality rate. Method : retrospective analysis was performed on patients with SCAP admitted to the ICU between March 2002 and February 2004 in the Asan Medical Center. The basic demographic data, bacteriologic study results and initial antimicrobial regimen were examined for all patients. The clinical outcomes including the ICU length of stay, the ICU mortality rate, and 30 days mortality rates were assessed by the initial antimicrobial regimen. Results : One hundred sixteen consecutive patients were admitted to the ICU (mean age 66.5 years, 81.9 % male, 30 days mortality 28.4 %). The microbiologic diagnosis was established in 58 patients (50 %). The most common pathogens were S. pneumoniae (n=12), P. aeruginosae (n=9), K. pneumonia (n=9) and S. aureus (n=8). The initial empirical antimicrobial regimens were classified as: ${\beta}$-lactam plus macrolide; ${\beta}$-lactam plus fluoroquinolone; anti-Pseudomonal ${\beta}$-lactam plus fluoroquinolone; Aminoglycoside combination regimen; ${\beta}$-lactam plus clindamycin; and ${\beta}$-lactam alone. There were no statistical significant differences in the 30-day mortality rate according to the initial antimicrobial regimen (p = 0.682). Multivariate analysis revealed that acute renal failure, acute respiratory distress syndrome and K. pneumonae were independent risk factors related to the 30 day mortality rate. Conclusion : S. pneumoniae, P. aeruginosae, K. pneumonia and S. aureus were the most common causative pathogens in patients with SCAP and K. pneumoniae was an independent risk factor for 30 day mortality. The initial antimicrobial regimen was not associated with the 30-day mortality.

• Sleep Medicine and Psychophysiology
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• v.17 no.2
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• pp.100-108
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• 2010

Objectives: "Internet-addiction" came into common use not only in clinical setting but also in everyday life. But, pathophysiology and diagnostic criteria of the internet addiction remain unknown. Because adolescents are in developing period, they might be vulnerable to the internet addiction, depression and sleep-related problem. The objectives of this study were to investigate the characteristics of internet addiction and its association with sleep pattern and depression in Korean adolescence. Methods: Subjects were 799 middle and high school students in Seoul, Korea. We administered a self-reported questionnaire including socio-demographic data, Korean versions of Young's Internet Addiction Scale (YIAS), Pittsburgh Sleep Quality Index (PS-QI), the Center for Epidemiologic Studies for Depression Scale (CES-D) and questions about internet using patterns. Data of 696 subjects were included in analysis. Chi-square tests were used to analyze proportional differences, and ANOVA with post-hoc tests were used to analyze differences among groups. Partial correlation analyses were performed to analyze the correlation of internet addiction with other variables (two-tailed, p<0.05). Results: Of the 696 participants (grade 2 of middle school; M2 135 vs. grade 1 of high school; H1 238 vs. grade 2 of high school; H2 323), 2.0% (n=14) were internet-addicted (IA), 27.7% (n=193) were over-using (OU) and 70.3% (n=489) were not-addicted (NA). The mean scores of YIAS, PSQI and CES-D scores were 35.24${\pm}$12.78, 5.53${\pm}$3.04 and 16.72${\pm}$8.69, respectively. In higher grade students, average total sleep time was shorter (M2 426.20${\pm}$67.68 min. vs. H1 380.47${\pm}$62.57 min. vs. H2 354.67${\pm}$73.37 min., F=51.909, p<0.001), and PSQI (4.69${\pm}$3.14 vs. 5.42${\pm}$3.15 vs. 5.97${\pm}$2.83, F=8.871, p<0.001) CES-D (13.53${\pm}$8.37 vs. 16.96${\pm}$8.24 vs. 17.87${\pm}$8.84, F=12.373, p<0.001) scores were higher than those of lower grade students. Comparing variables among IA, OU and NA groups, computer using time not for study (96.36${\pm}$63.31 min. vs. 134.92${\pm}$86.79 min. vs. 213.57${\pm}$136.87 min., F=34.287, p<0.001) and portable device using time not for study (84.22${\pm}$79.11 min. vs. 96.97${\pm}$91.89 min. vs. 152.31${\pm}$93.64 min., F= 5.400, p=0.005) were different among groups. PSQI (5.26${\pm}$2.97 vs. 6.08${\pm}$2.97 vs. 7.50${\pm}$4.41, F=8.218, p<0.001) and CES-D scores (15.40${\pm}$8.08 vs. 19.05${\pm}$8.42 vs. 30.43${\pm}$13.69, F=32.692, p<0.001) were also different among groups. YIAS score were correlated with computer using time not for study (r=0.356, p<0.001) and portable device using time not for study (r= 0.136, p<0.001). PSQI score (r=0.237, p<0.001) and CES-D score (r=0.332, p<0.001). YIAS score and PSQI score (r=0.131, p= 0.001), YIAS and CES-D score (r=0.265, p<0.001), PSQI score and CES-D score (r=0.357, p<0.001) were correlated each other. Conclusion: These results suggested that adolescents' internet-addiction was correlated with not only computer and portable device using time not for study but also depression and sleep-related problems. We should pay attention to depression and sleep-related problems, when evaluating internet-addiction in adolescents.

• Economic and Environmental Geology
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• v.5 no.4
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• pp.187-209
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• 1972

Drilling position is one of the most important factors affecting on the blasting effects. There has been many reports on several blasting factors of burn-cut by Messrs. Brown and Cook, but in this study the author tried to compare drilling positions of burn-cut to pyramid-cut, and also to correlate burn-cut effects of drilling patterns, not being dealt by Prof. Ito in his theory, which emphasized on dynamical stress analysis between explosion and free face. According to former theories, there break out additional tensile stress reflected at the free face supplemented to primary compressive stress on the blasting with one-free-face. But with these experimented new drilling patterns of burn-cut, more free faces and nearer distance of each drilling holes make blasting effects greater than any other methods. To promote the above explosive effect rationary, it has to be considered two important categories under-mentioned. First, unloaded hole in the key holes should be drilled in wider diameter possibly so that it breaks out greater stress relief. Second, key holes possibly should have closer distances each other to result clean blasting. These two important factors derived from experiments with, theories of that the larger the dia of the unloaded hole, it can be allowed wider secondary free faces and closes distances of each holes make more developed stress relief, between loaded and unloaded holes. It was suggested that most ideal distance between holes is about 4 clearance in U. S. A., but the author, according to the experiments, it results that the less distance allow, the more effective blasting with increased broken rock volume and longer drifted length can be accomplished. Developed large hole burn-cut method aimed to increase drifting length technically under the above considerations, and progressive success resulted to achieve maximum 7 blasting cycles per day with 3.1m drifting length per cycle. This achievement originated high-speed-drifting works, and it was also proven that application of Metallic AN-FO on large hole burn-cut method overcomes resistance of one-free-face. AN-FO which was favored with low price and safety handling is the mixture of the fertilizer or industrial Ammonium-Nitrate and fuel oil, and it is also experienced that it shows insensible property before the initiation, but once it is initiated by the booster, it has equal explosive power of Ammonium Nitrate Explosives (ANE). There was many reports about AN-FO. On AN-FO mixing ratio, according to these experiments, prowdered AN-FO, 93.5 : 6.5 and prilled AN-FO 94 : 6, are the best ratios. Detonation, shock, and friction sensities are all more insensitive than any other explosives. Residual gas is not toxic, too. On initation and propagation of the detonation test, prilled AN-FO is more effective than powered AN-FO. AN-FO has the best explosion power at 7 days elapsed after it has mixed. While AN-FO was used at open pit in past years prior to other conditions, the author developed new improved explosives, Metallic AN-FO and Underwater explosive, based on the experiments of these fundmental characteristics by study on its usage utilizing AN-FO. Metallic AN-FO is the mixture of AN-FO and Al, Fe-Si powder, and Underwater explosive is made from usual explosive and AN-FO. The explanations about them are described in the other paper. In this study, it is confirmed that the blasting effects of utilizing AN-FO explosives are very good.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.42-56
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• 2005

Hyperlipidemia is one of the risk factors for coronary artery disease. Despite of epidemiological evidence that tea consumption is associated with the reduced risk of coronary heart disease, experimental studies designed to show that drinking tea affects blood lipid concentration or oxidative stress have been unsuccessful. The purpose of this study was to investigate whether functional tea (three servings/day) supplement with medical nutrition therapy (MNT) lead to a beneficial outcomes in mildly hyperlipidemic adults. From February to October, 2003, the 43 hyperlipidemic (23 men, 20 women) subjects (total cholesterol$\geq$200 mg/dL or triglyceride$\geq$150 mg/dL) admitted to K Medical Center were studied. Subjects were randomly divided into 3 groups; placebo tea (PT), half dose of functional tea (HFT), full dose of functional tea (FFT). During 12 weeks of study period, the subjects were given placebo or functional tea daily with MNT. Anthropometric measurements, blood chemical analysis including lipid levels, total superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels, and dietary assessment were carried out at the beginning and end of experiment. The effects of functional tea were compared with the placebo in randomized clinical trial study. The placebo was prepared to match with the functional tea in color and taste. After the 12 weeks of MNT, the subjects had regular and balanced meal pattern. Consumption of foods high in cholesterol and saturated fat, salty foods, fried foods, and instant foods decreased significantly in all three groups (p<0.05). Intake of energy and cholesterol also decreased (p<0.05). Drinking three servings per day (390 mL/day) of functional tea significantly reduced the levels of blood triglyceride (HFT, 42.5%; FFT, 29.4%), total cholesterol (HFT, 8.5%; FFT, 13.7%), and atherogenic index (HFT, 14.6%; FFT, 21.7%). Whereas no changes were found in the LDL-, HDL-cholesterollevels, and LDL/HDL ratio. Plasma homocysteine (Hcy) concentration decreased significantly (p<0.05) in functional tea groups (HFT, 14.9%; FFT, 14.1%). SOD increased significantly (p<0.05) in HFT (8.3%). GSH-Px increased significantly (p<0.05) in FFT (12.8%). In conclusion, the MNT improved the dietary habits, in addition, functional tea supplement decreased blood lipid levels and Hcy, and increased SOD and GSH-Px levels. These results indicate that functional tea consumption may decrease the risk of cardiovascular disease via improving blood lipid levels and antioxidant status.

• Clinical and Experimental Pediatrics
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• v.49 no.12
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• pp.1329-1339
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• 2006

Purpose : Failure of hematopoietic stem cell transplantation(HSCT) may be encountered in practice because of either relapse of the malignancy or dysfunction of the graft. Second HSCT may be the only option for some patients whose initial HSCT failed. Methods : From May, 1991 to December, 2004, 115 HSCTs were performed at the Pediatric Blood & Marrow Transplantation Center, Chonnam National University. This study was a retrospective analysis of the medical records of 15 patients who received the second HSCT after initial graft. Results : Among eight patients with nonmalignant diseases, two patients underwent the second HSCT because of primary graft failure and five because of late graft rejection. The remaining Fanconi anemia patient was re-transplanted due to development of AML. Two patients died and one experienced primary graft failure, but is still alive. The Kaplan-Meier 5-year overall survival rate was 75 percent and the disease free survival rate was 62.5 percent in nonmalignant diseases. All malignant patients underwent second transplants because of relapses. Four died of relapse and one of treatment-related complications. The Kaplan-Meier 2-year overall and event free survival rate was 28.6 percent each in malignant diseases. Conclusion : Second HSCT for graft dysfunction of nonmalignant disease seems to be feasible and should be considered as a standard practice. The relapse of malignant diseases remains a big obstacle even after the second HSCT, although a small portion of patients might be salvaged. Further investigation of novel therapeutic strategies, as well an the understanding of the biology should be explored.