• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.506-515
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• 2003

Six barley varieties that showed different degree of drought tolerance were grown with and without drought stress treatment (control), and investigated for the temporal changes in growth and several physiological traits after drought treatment. Soil water potential was -0.05 ㎫ at the initial stage of drought treatment and dropped to -0.29 ㎫ at 19 days after withholding irrigation. Soil water potential (SWP) maintained at -0.05 ㎫ in the control. The dry weight (DW) under the drought treatment were reduced compared to the control as follows: Dicktoo-S (short awn), 69% ; Dicktoo-L (long awn), 70%; Dicktoo-T (tetra), 86%; Dongbori-1, 69%; Suwonssalbori-365, 55% and Tapgolbori, ,37%. Dicktoo lines and Dongbori-1 were more tolerant than Suwonssalbori-365 and Tapgolbori. Leaf relative water contents (RWC) and leaf water potential (LWP) decreased obviously under the drought condition, the decrease being greater especially in the less drought-tolerant barley genotypes. Dongbori-1 and Dicktoo-L in drought treatment showed net photosynthesis of 38% and 17% compared to the control, respectively, and the other four genotypes much lower photosynthesis of 1.1% to 7.0%. Stomatal conductance, mesophyll conductance, and the photochemical efficiency (Fv/Fm) of PS II were reduced by drought treatment, the reduction being greater in drought-sensitive genotypes. The drought-tolerant genotypes had greater osmotic adjustment (OA) capacity under water stress. Thus, the decrease of RWC and LWP was lower and the turgor pressure conservation capacity was higher under water stress in drought-tolerant genotypes. Drought-tolerant genotypes showed less decrease of photosynthesis because stomatal conductance, mesophyll conductance and the ratio (Fv/Fm) of the variable to maximal fluorescence of drought-resistant genotype was decreased less in the drought stress condition. In conclusion, the drought-tolerant genotypes had better water conservation capacity through efficient OA, and this led to the lower decrease of photosynthesis and growth in water stress condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.516-526
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• 2003

Thirty-six barley varieties including Korean modern and local varieties were tested for drought-tolerance in the field of plastic rain shelter, Drought treatment was initiated at initial tillering stage (March 27, 2002) by withholding irrigation and lasted until harvest. Soil water potential maintained at around -0.05㎫ in the control plot and varied from -0.05㎫ (at the initial stage of drought treatment) to -0.29㎫ in the drought treatment plot. At forty days after drought treatment, relative water content (RWC), osmotic potential (OP), osmotic adjustment (OA), and $^{13}\textrm{C}$ discrimination ($\Delta$) were measured and then plants were sampled for leaf area index (LAI) and dry weight (DW). Barley was harvested at maturity for determining DW, grain yield, 1000 grains weight and number of spikelet. The tested varieties revealed wide spectrum of drought tolerance. Dongbori-1, Chalbori, Changyeongjaerae, Samdobori and Weolseong 87-31 showed strong drought-tolerance while Songhagbori and Suwonmaeg360 showed weak drought-tolerance. The drought injury indexes (drought/control ratio) of DW and yield revealed significant positive correlation with leaf RWC in drought treatment plot and $\Delta$ in the control plot, but obvious negative correlation with leaf OP and OA under drought condition. In addition, all the drought indexes of OP, $\Delta$ and RWC showed obvious positive correlation with the drought injury indexes of DW, 1000 grain weight and yield. Thus, OP and RWC under drought condition and $\Delta$ under well-watered condition would be used as the evaluation criteria for drought- tolerance of barley genotypes. However, further investigation is needed for the relationship between $\Delta$ and drought-tolerance as the other reports were not consistent with our result.

• The Korean Society of Law and Medicine
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• v.18 no.2
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• pp.105-138
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• 2017

This is case comments of several representative legal cases regarding self- determination right of patient. In a case in which an intoxicated patient attempted suicide refusing treatment, the Supreme Court ruled that the medical team's respect for the patient's decision was an act of malpractice, and that in particular medical situations (medical emergencies) the physician's duty to preserve life supersedes the patient's rights to autonomy. Afterwards, at the request of the patient's family, and considering the patient's condition (irrecoverable death stage, etc.) consistent with a persistent vegetative state, the Supreme Court deduced the patient's intention and decide to withdraw life-sustaining treatment. More recently, regarding patients who refuse blood transfusions or other necessary treatment due to religious beliefs, the Supreme Court established a standard of judgment that can be seen as conferring equal value to the physician's duty to respect patient autonomy and to preserve life. An empirical study of legal precedent with regard to cases in which the physician's duty to preserve life conflicts with the patient's autonomy, grounded in respect for human dignity, can reveal how the Court's perspective has reflected the role of the patient as a decision-making subject and ways of respecting autonomy in Korean society, and how the Court's stance has changed alongside changing societal beliefs. The Court has shifted from judging the right to life as the foremost value and prioritizing this over the patient's autonomy, to beginning to at least consider the patient's formally stated or deducible wishes when withholding or withdrawing treatment, and to considering exercises of self determination right based on religious belief or certain other justifications with informed refusal. This will have a substantial impact on medical community going forward, and provide implicit and explicit guidance for physicians who are practicing medicine within this environment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.4
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• pp.310-317
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• 2006

This study was conducted to investigate the influence of drought stress during the pod developing and seed filling stage on source-sink relationships of soybean (Glycine max). Drought treatments were imposed by withholding water at the full-pod stage, 19 days after flowering, and then limited watering was relieved at 15 days after the initiation of drought treatment. Soybean seed yield was reduced by 39% mainly due to decreased pod number under drought stress, but the 100-seed weight was relatively less reduced. In spite of the 15-day drought during the full-pod stage, soybean produced good seeds showing similar l00-seed weight, protein, starch and soluble sugar content to those from the well-watered. Although drought during the full-pod stage caused source limitations; i.e. accelerated leaf senescence and reduced leaf soluble sugars, it did not cause limitations of other source characteristics such as SGR and leaf starch level. This is because the reduction in size of sinks, such as pod and seed abortions compensated for source limitations, resulting in balanced source-sink as expressed by LAR and the ratio of leaf area to seed dry weight. Drought stress during the pod developing and seed filling stage did not disrupt the source-sink balance

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.173-177
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• 2019

Objective: We investigated the clinical characteristics of men with testosterone replacement therapy (TRT)-induced hypogonadism and its effect on assisted reproductive technology (ART) in infertile couples. Methods: This study examined the records of 20 consecutive male patients diagnosed with azoospermia or severe oligozoospermia (< 5 × 10⁶/mL) who visited a single infertility center from January 2008 to July 2018. All patients were treated at a primary clinic for erectile dysfunction or androgen deficiency symptoms combined with low serum testosterone. All men received a phosphodiesterase 5 inhibitor and TRT with testosterone undecanoate (Nebido^®) or testosterone enanthate (Jenasteron^®). Patients older than 50 years or with a chronic medical disease such as diabetes were excluded. Results: The mean age of patients was 37 years and the mean duration of infertility was 16.3 ± 11.6 months. At the initial presentation, eight patients had azoospermia, nine had cryptozoospermia, and three had severe oligozoospermia. Serum follicle-stimulating hormone levels were below 1.0 mIU/mL in most patients. Three ongoing ART programs with female factor infertility were cancelled due to male spermatogenic dysfunction; two of these men had normal semen parameters in the previous cycle. After withholding TRT, serum hormone levels and sperm concentrations returned to normal range after a median duration of 8 months. Conclusion: TRT with high-dose testosterone can cause spermatogenic dysfunction due to suppression of the hypothalamic-pituitary-testicular axis, with adverse effects on infertility treatment programs. TRT is therefore contraindicated for infertile couples attempting to conceive, and the patient's desire for fertility must be considered before initiation of TRT in a hypogonadal man.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.3
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• pp.223-231
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• 1994

To investigate effects of water stress on leaf water potential, nitrate reductase activity and abscisic acid content, Paldalkong, Saealkong and Danyeobkong were subjected to water stress by polyethyene glycol(PEG, MW=6,000) in the water culture and withholding irrigation in soil culture. Leaf water potential and nitrate reductase activity decreased with increaseing of PEG concentration in the water culture. These were higher at 3rd and 5th leaf stage than at 1st leaf stage. Leaf water potential showed no significant differance among the varieties, but nitrate redutase activity was higher in Paldalkong than in Saealkong and Danyeobkong. Leaf water potential and nitrate reductase activity decreased approximately 2.2 times (-1.67 MPa/-0.75MPa) and 47%(3.1${\mu}$ mole nitrite/g.DW/hour/15.9${\mu}$ mole nitrite/g.DW/hour) to control, respectively, after 3 days from water stress treatment in the soil culture. According to increasing PEG concentration, abscisic acid content increased in the water culture and was higher at 5th leaf stage than at 1st and 3rd leaf stage. Paldalkong showed the highest abscisic acid content. Abscisic acid content increased approximately 1.7 times (9.9nmole/g.DW/5.7nmole/g.DW) compared to the control after 3 days from water stress treatment in the soil culture.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.288-299
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• 2017

This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

• Journal of Hospice and Palliative Care
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• v.11 no.3
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• pp.140-146
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• 2008

Purpose: Sooner of later, end-of-life care decision-making will unfold and be settled during the professional lives of medical students. However, there is prevalent ambiguity and uncertainty between the palliative treatment and euthanasia. We conducted this survey to investigate attitudes of medical students towards end-of-life making decisions, and to find out which factors primarily influenced the attitudes. Methods: A study was conducted among medical students at one university, the Republic of Korea. A written questionnaire was sent to all the 1st, 2nd, and 3rd-year medical students. It presented 5 statements on end-of-life decision-making. Students were asked whether they agreed or disagreed with each statement. Results: The response rate was 74.4%, and 267 questionnaires were analyzed. Percentages of agreement with each statements on Voluntary active euthanasia (VAE), Physician assisted suicide (PAS), Withholding life-sustaining management, Withdrawing life-sustaining management, and Terminal sedation (TS) was 37.1%, 21.7%, 58.4%, 60.3%, and 41.6%, respectively. The grade of students, religious activity, and educational experience were determinant factors. Agreement on each statements was higher in the low religious activity group than in the high religious activity group. Agreement on TS was higher among 3rd year students during their clerkship than among 1st and 2nd year students. Age of students and the experience of dying-people care had no significant influence. Conclusion: In end-of-life decision-making, religious and educational factors influenced medical students' attitudes. Especially, the experience of education during clerkship had significant influence on the attitude. Proper teaching on end-of-life decisions should further be considered during medical students' clerkship.

• Journal of Hospice and Palliative Care
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• v.15 no.1
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• pp.30-35
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• 2012

Purposes: Most medical schools in Korea do not provide adequate education in end-of-life care. This study was designed to illustrate the need to improve end-of-life care education and to assess the effect of the education on fourth-year medical students' awareness and attitude towards hospice and palliative care for terminally ill patients. Methods: One hundred sixty six fourth-year medical students were surveyed with questionnaires on end-of-life care before and after they received the education. Results: Before receiving the education, students most frequently answered "at the end of life" (33.6%) was appropriate time to write an advance medical directive. After the education, the most frequent answer was "in healthy status" (58.7%). More students agreed to withholding or withdrawing futile life-sustaining treatment increased after the education (48.1% vs. 92.5% (P<0.001) for cardiopulmonary resuscitation, 38.3% vs. 92.5% (P<0.001) for intubation and mechanical ventilation, 39.1% vs. 85.8% (P<0.001) for inotropics, 60.9% vs. 94.8% (P<0.001) for dialysis and 27.8% vs. 56.0% (P<0.001) for total parenteral nutrition). Significantly more students opposed euthanasia after the education (46.6% vs. 82.1%, P<0.001). All students agreed to the need for education in end-of-life care. Conclusion: After reflecting on the meaning of death through the end-of-life care education, most students recognized the need for the education. The education brought remarkable changes in students' awareness and attitude towards patients at the end of life. We suggest end-of-life care education should be included in the regular curriculum of all medical schools in Korea.