본 연구는 잉여슬러지와 차아염소산나트륨을 혼합하여 제조한 차아염소산나트륨 처리 슬러지를 침지형 분리막이 설치된 생물반응조에 주입하여 수처리 미생물에 기질을 공급하고 수처리에 적합한 pH와 알칼리도를 유지함으로써 응집제 주입 없이 방류수의 총질소 농도 20 mg/L, 총인 농도 0.2 mg/L 이하로 처리할 수 있는 MBR 하수처리공정을 개발하였다. 개발된 공정은 별도의 응집제 주입 없이 질소와 인의 법적 방류수 수질기준 을 만족하였고, 향후 하수처리장 약품비용 절감에도 기여할 것으로 기대된다.

Polytetrafluoroethylene (PTFE) membrane has high resistance to chlorine, which is a great advantages in chemical cleaning to recover water flux during membrane processes in drinking water systems. A humic kaolin water with approximately 4 mg/L of DOC and 10 NTU of turbidity was prepared as a feed water. Coagulation pretreatment with or without settling was applied. The coagulation with settling showed the greatest water production. The reduced flux was effectively recovered by NaOCl cleaning, i.e., 21% recovery by 50 mg/L of NaOCl cleaning and 49% recovery by 500 mg/L NaOCl cleaning. The images of SEM and AFM analyses were corresponded to the water flux variation. However, when the floc was accumulated on the membrane surfaces, the efficiency of NaOCl cleaning was substantially limited. In addition, dynamic contact angle became greater after cleaning, which indicates changes in characteristics of fouling layer such as surface hydrophobicity. Proper cleaning technologies during enhanced backwash using NaOCl would expand application of PTFE membranes in drinking water systems.

Recent studies indicate that reactive oxygen species (ROS) can act as modulators of neuronal activity, and are critically involved in persistent pain primarily through spinal mechanisms. In this study, we investigated the effects of NaOCl, a ROS donor, on neuronal excitability and the intracellular calcium concentration ([Ca²⁺]_i) in spinal substantia gelatinosa (SG) neurons. In current clamp conditions, the application of NaOCl caused a membrane depolarization, which was inhibited by pretreatment with phenyl-N-tert-buthylnitrone (PBN), a ROS scavenger. The NaOCl-induced depolarization was not blocked however by pretreatment with dithiothreitol, a sulfhydrylreducing agent. Confocal scanning laser microscopy was used to confirm whether NaOCl increases the intracellular ROS level. ROS-induced fluorescence intensity was found to be increased during perfusion of NaOCl after the loading of 2′,7′-dichlorofluorescin diacetate (H₂DCF-DA). NaOCl-induced depolarization was not blocked by pretreatment with external Ca²⁺ free solution or by the addition of nifedifine. However, when slices were pretreated with the Ca²⁺ ATPase inhibitor thapsigargin, NaOCl failed to induce membrane depolarization. In a calcium imaging technique using the Ca²⁺-sensitive fluorescence dye fura-2, the [Ca²⁺]_i was found to be increased by NaOCl. These results indicate that NaOCl activates the excitability of SG neurons via the modulation of the intracellular calcium concentration, and suggest that ROS induces nociception through a central sensitization.

본 연구는 춘란 야생 변이종의 육종을 위한 기초 자료 를 얻고자 실시하였으며, 야생종의 개화시기를 꽃봉오리, 반개화, 개화, 개화 후 10일, 개화 후 20일의 5단계로 나 누어 자가 수분시킨 후 삭과의 형태적 특성과 발아율을 조사한 결과이다. 착과율은 개화 후 20일에 교배한 것에 서 100%로 가장 높았고, 삭과의 무게는 반개화 때 교배 한 것이 가장 무거웠다. 5단계로 나누어 발아율을 조사한 결과 반개화에서 가장 높게 나타났으며, 교배 후 채종 일수를 150일, 165일, 180일의 3단계로 달리하여 발아율 을 조사한 결과에서는 교배 후 채종일수를 150일에 파종 한 종자에서 5%로 가장 높게 나타났다. NaOCl 처리를 통한 발아율을 조사한 결과에서는 2%로 처리한 것에서 53.3%의 발아율을 보여 가장 좋은 결과를 나타내었다.

Recent studies have implicated reactive oxygen species (ROS) as determinants of the pathological pain caused by the activation of peripheral neurons. It has not been elucidated, however, how ROS activate the primary sensory neurons in the pain pathway. In this study, calcium imaging was performed to investigate the effects of NaOCl, a ROS donor, on the intracellular calcium concentration ([Cα2+]i) in acutely dissociated dorsal root ganglion (DRG) neurons. DRG was sequentially treated with 0.2 mg/ml of both protease and thermolysin, and single neurons were then obtained by mechanical dissociation. The administration of NaOCl then caused a reversible increase in the [Cα2+]i], which was inhibited by pretreatment with phenyl-N-tertbuthylnitrone (PBN) and isoascorbate, both ROS scavengers. The NaOCl-induced [Cα2+]i] increase was suppressed both in a calcium free solution and after depletion of the intracellular Cα2+ pool by thapsigargin. Additionally, this increase was predominantly blocked by pretreatment with the transient receptor potential (TRP) antagonists, ruthenium red (50 μM) and capsazepine (10 μM). Collectively, these results suggest that an increase in the intracellular calcium concentration is produced from both extracellular fluid and the intracellular calcium store, and that TRP might be involved in the sensation of pain induced by ROS.

The purposes of this study were to evaluate the removal characteristics of COD, Ni, and P and to derive appropriate operating conditions for the plating wastewater according to NaOCl reaction time and pH operating conditions in the BPC unit process during the plating wastewater treatment process. As a results of evaluating the removal characteristics for raw wastewater by each BPC unit process, the removal efficiencies of COD, Ni and P in BPC 1-1 unit process were 72.8%, 99.1%, and 100.0%. Therefore, the proper reaction time of NaOCl was derived as 21.1 minutes. In order to maintain the +800 mV ORP and the reaction time of 20 minutes, the temporary injection and continuous injection of NaOCl in the BPC unit process were 13.7 mL and 18.7 mL, respectively. It was found that the temporary injection method of NaOCl reduced the chemical cost by 36.5% compared to the continuous injection method. Also, Ni showed the highest removal efficiency of 97.8% at pH 10.5. On the other hand, P showed a removal efficiency of 57.4% at pH 10.0.

This study was carried out to examine the effective wet harvesting solution for development of wet distribution system in standard chrysanthemum (Dendranthema grandiflorum) ‘Baekma’. The cut flowers were treated immediately in floral preservative solutions or dry condition after harvesting, and then the effects on quality of cut flower were compared. Also, we investigated the effects of NaOCl and sucrose on vase life and quality of cut flower. When the cut flowers were treated immediately in tap water, Chrysal OVB, Floralife, Hiflora solutions after harvesting, flower diameter and fresh weight of cut flower increased compared to dry condition treatment. In single treatment of 100 mg･L-1 NaOCl as wet harvesting solution, flower diameter and fresh weight of cut flower increased more than other treatments, and vase life was prolonged to 1.5 days than control. But, flower diameter and fresh weight of cut flower decreased in 0 or 200 mg･L-1 NaOCl. When the cut flowers were treated in combination solution of 100 mg･L-1 NaOCl and 0.1% sucrose, the flower diameter was the largest by 9.8 cm, and fresh weight of cut flower was maintained the highest in holding solution. On the other hand, flower diameter and fresh weight of cut flower were lowest in combination solution of 100 mg･L-1 NaOCl and 2.5% sucrose. There was no difference in vase life between treatments mixed with NaOCl and sucrose. Therefore, it was suggested that treatment mixed with 100 mg･L-1 NaOCl and 0.1% sucrose as wet harvesting solution was the most effective for vase life and quality of cut flower in standard chrysanthemum ‘Baekma’.

This study was carried out to examine the effects of NaOCl, sucrose, and BA concentration as pretreatment solution on quality and vase life of cut flowers in Dendranthema grandiflorum ‘Jinba’. Flower diameter, fresh weight, and vase life in control and 0 mg･L -1 NaOCl treatments decreased, and the treatment with 100~200 mg･L -1 NaOCl was more effective in the quality and vase life. In pretreatment with 2.5% sucrose solution, flower diameter and fresh weight decreased and vase life was shortest due to the rapid leaf wilting. However, pretreatment with 0.1% sucrose solution increased the flower diameter and fresh weight, and showed the longest vase life. When more than 80 mg･L -1 BA was treated with pretreatment solution, flower diameter and fresh weight decreased, and vase life was shortened. With pretreatment of 20 mg･L -1 BA, the flower diameter was bigger than in the other treatments, but it was no effect on fresh weight and vase life. Therefore, it was suggested that pretreatment solution mixed with 200 mg･L -1 NaOCl, 0.1% sucrose, and 20 mg･L -1 BA was the most effective for the quality and vase life of cut flowers in standard chrysanthemum ‘Jinba’.