• Journal of the Korean Wood Science and Technology
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• v.28 no.2
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• pp.49-56
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• 2000

This study was designed to investigate the adsorption of heavy metal ions by untreated bark according to the treatment conditions of aqueous solution. The effect of temperature and pH of aqueous solution, particle size of bark, addition of light metal ions on the adsorption was examined, and the competition in adsorption among heavy metal ions was also evaluated. te The adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased with increasing themperature of solution from $-5^{\circ}C$ to $10^{\circ}C$ however, it was relatively constant at temperatures between $10^{\circ}C$ and $55^{\circ}C$. The adsorption ratio of $Cr^{6+}$ increased continuously with increasing the temperature of solution. The maximum adsorption ratio of $Cu^{2+}$, $Zn^{2+}$, and $Pb^{2+}$ was noted at pHs ranged 6 to 7; however, the adsorption ratio declined sharply on either sides of the optimum. The adsorption ratio of $Cr^{6+}$ decreased continuously with increasing the pH of solution. The adsorption ratio increased as decreasing the particle size of bark, and there was little differences in adsorption tendency between pine and oak bark. By the addition of $Ca^{2+}$ or $Mg^{2+}$(10~25 ppm), the adsorption ratio of $Cu^{2+}$ and $Zn^{2+}$ increased. An increase of the adsorption ratio was higher in oak bark than in pine bark. However, the adsorption ratio of $Pb^{2+}$ and $Cr^{6+}$ was not affected by the addition of light metal ions. As the mixed solution of 2 or 3 kinds of heavy metal ions($Cu^{2+}$, $Zn^{2+}$, $Pb^{2+}$) was treated with the untreated bark, the adsorption of $Zn^{2+}$ decreased considerably because of the competitive adsorption among heavy metal ions. Also the adsorption of $Cu^{2+}$ was more and less reduced. However the adsorption of $Pb^{2+}$ was not affected by the presence of other heavy metal ions.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.1-8
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• 2008

The lateral strength test of bending type was done to investigate the lateral capacity of the double bolt connection of domestic larix glulam according to bolt spacing. In the shear specimen, which is bolted connection in the inserted plate type, the hole of bolt was made, changing the diameter of bolt (12 mm and 16 mm), the number of bolt (single bolt : control and double bolt), the direction of bolt row (in parallel to grain : Type-A and in perpendicular to grain : Type-B) and the bolt spacing (Type-A : 4 d and 7 d and Type-B : 3 d and 5 d). Lateral capacity and failure mode of bolt connection were compared according to conditions. In prototype design (KBCS, 2000), the reduction factor of the allowable shear resistance that the bolt spacing is reduced was calculated. The results were as follows. 1) Bearing stress per bolt in the single and double bolt connection of Type-A was directly proportional to bolt diameter and bolt spacing. Bearing stress of Type-B decreased as bolt diameter was increased, and decreased by 2~10% when bolt diameter was increased. 2) In the single bolt connection and the double bolt connection of Type-A, the splitted failure was formed in the edge direction. When the bolt spacing was 3 d in Type-B, bolt was yielded more in the part of tension than in the part of compression, and the splitted failure started at the bolt in the part of tension. In the 5 d spacing specimen, the bolt in the part of tension was yielded similarly to bolt in the part of compression, and the splitted failure started in the part of compression. 3) In the prototype design, the reduction factor was calculated by non-dimensionizing the yielding load in the standard of bolt spacing (Type A : 7 d and Type B : 5 d). In 12 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.87 and 0.55, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.55, respectively. In 16 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.96 and 0.76, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.77, respectively.

• Journal of Chest Surgery
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• v.38 no.6 s.251
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• pp.403-409
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• 2005

Pulmonary atresia with intact ventricular septum is morphologically heterogeneous, and the surgical outcome remains suboptimal compared to other complex congenital heart defects. We evaluated the long-term results for repair of pulmonary atresia with intact ventricular septum, Material and Method: Between January 1992 and June 2004, 38 patients underwent repair of pulmonary atresia with intact ventricular septum. The average age was 18 days $(2\~382\;days)$. The average Z-value of the tricuspid annulus diameter was -3.1$(-5.6\~0.8)$. Thirteen $(36\%)$ patients had right ventricle-to-coronary artery fistulas, and $4(11\%)$ patients had right ventricle-dependent coronary circulation. Average follow-up was 55 months $(3\;months\~2.2\;years)$, Result: Twenty-four patients under-went initial right ventricle (RV) decompression and 14 patients underwent systemic-to-pulmonary arterial shunt only. The average size of the tricuspid annulus of the patients who underwent RV decompression was significantly larger than that of the patients who underwent systemic-to-pulmonary arierial shunt only (Z-value -2.2 vs. -4.8, p=0.000). There were $5(13\%)$ early and 1 late deaths. Early deaths occurred in 3 patients who had undergone RV decompression, and in 2 patients who had undergone systemic-to-pulmonary arterial shunt only (p=1.0). Biventricular repair was achieved in $12(32\%)$ patients, single ventricular repair in $8(21\%)$, and one and a half ventricular repair in $4(l1\%)$ patients. Nine $(24\%)$ patients are waiting for the definitive repair. Kaplan-Meier survival at 5 and 8 years was $83.2\%$, respectively. Conclusion: Most of the deaths occurred after the initial palliation. Overall long-term survival was satisfactory. Early mortality should be reduced with careful preoperative evaluation and proper surgical strategy.

• Journal of Chest Surgery
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• v.29 no.12
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• pp.1306-1315
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• 1996

This study reviewed the changes of hemodynamlcs and centrAl pulmonary artery dimension in 54 patients who underwent bidirectional cavopulmonary shunt(BCPS) between February 1992 and December 1995 at Seoul National University Childrell's Hospital. Ag and body weight of patients averaged 36.8 $\pm$ 37.7 months and 8.0$\pm$3.0 kg, respectively Eightynine percent of patients had more than 2 violations of the risk factors for Fontan operation, resulting overall hospital mortality of 16.6%(9154). Serial hemodynamic and anglographic examinations before and mean 16.3 $\pm$ 14.3 months iirter BCPS were compared. The arterial oxygen saturation improved from a preoperative value of 71 9: 10.1 % to 79.H $\pm$ 8. 5% (n:4), p<0.05). The values of arterial oxygen saturation were lower as the age of the patients with BCPS in place was older(n=22, R'=0.341, p=0.004). A mean pulmonary artery pressure and pulmonary vascular resistance reduced from 31 $\pm$17 to 1).5$\pm$3.SmmHg(n=22, p<0.05) and from ).2$\pm$2.1 to 2.3$\pm$2.7 unit (n=7. p>0.05), respectively. Follow-up study showed a significant Increase of absolute values of ipsilateral pulmoanry artery (n: 14, p<0.05), but no change of contralateral pulmonary artreries (n: 14. p=not significant(HSI). However, there w re significant decreases in diameters of both ipsilateral and contralateral pulmonary arteries standardized by patients' body surface areas(16.8% decrease, n: 14, p< 0. 05 for ipsilatreal, 25.1%, n=14, p<0.05 for contralateral). Pulmonary artery indices for cross sectional areas of both pulmonary arterises decreased 9.3 $\pm$ 13.8% with showing a trend of more decrease as the follow-up duration was longer, We conclude that the bidirectional cavopulmonary shunt provide an excellent.

• Journal of Chest Surgery
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• v.32 no.9
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• pp.773-780
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• 1999

Background: It has been demonstrated that brief periods of calcium depletion and repletion (calcium-free preconditioning, CP) have cardioprotective effects as seen in ischemic preconditioning(IP) which enhances the recovery of post-ischemic contractile dysfunction and reduces the incidence of reperfusion-induced arrhythmia or infarct size after a prolonged ischemia. In the present study, we tested this paradoxical phenomenon in isolated rabbit hearts. Material and Method: Hearts isolated from New Zealand white rabbits(1.5∼2.0 Kg body weight) were perfused with Tyrode solution using the Langendorff technique. After stabilizing the baseline hemodynamics, the hearts were subjected to 45 minutes of global ischemia followed by 120 minutes of reperfusion with IP(IP group, n=7) or without IP (ischemic control group, n=7). IP was induced by a single episode of 5 minutes global ischemia and 10 minutes reperfusion. In the CP group(n=7), the hearts were subjected to perfusion with Tyrode solution with calcium depletion for 5 minutes and repletion for 10 minutes, and 45 minutes of ischemia and 120 minutes of reperfusion. Left ventricular function including developed pressure, dP/dt, heart rate, left ventricular end-diastolic pressure and coronary flow was measured. Infarct size was determined by staining with 1% triphenyltetrazolium chloride and planimetry. Data were analyzed by a one-way analysis of variance and Tukey's post-hoc test. Result: In comparison with the ischemic control group, IP significantly enhanced the recovery of the left ventricular function including the left ventricular developed pressure, contractility, and coronary flow; in contrast, these functional parameters of the CP group tended to be lower than those of the ischemic control group. However, the infarct size was significantly reduced by IP or CP(p<0.05). Conclusion: These results suggest that in isolated Langendorff-perfused rabbit heart model, CP(induced by single episode of 5 minutes calcium depletion and 10 minutes repletion) could not improve the post-ischemic contractile dysfunction(after a 45-minute global ischemia) but it has an infarct size-limiting effect.

• Journal of Chest Surgery
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• v.37 no.5
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• pp.416-422
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• 2004

Acute renal failure (ARF) is a common postoperative complication after the cardiac surgery. Postoperative ARF have various causes, and are combined with other complications rather than being the only a complication. It deteriorates the general condition of the patient, and makes it difficult to manage the combined complications by disturbing the adequate medication and fluid therapy. We have planned this study to evaluate the effects of postoperative ARF after the on-pump coronary artery bypass surgery (CABG) on the recovery of patients and identify the risk factors. Method and Material: We reviewed the medical records of patients who underwent CABG with cardiopulmonary bypass by a single surgeon from Jan. 2000 to Dec. 2002, We checked the preoperative factors; sex, age, history of previous serum creationism over 2.0 mg/㎗, preoperatively last checked serum creatinine, diabetes, hypertension, left ventricular ejection fraction, intraoperative factors; whether the operation is an emergent case or not, cardiopulmonary bypass time, aortic cross clamp time, the number of distal anastomosis, postoperative factors: IABP. Then we have studied the relations of these factors and the cases of postoperative peak serum creatinine over 2.0 mg/㎗. Result: There were 19 cases with postoperative peak serum creatinine over 2.0 mg/㎗ in a total 97 cases. Dialysis were done in 3 cases for ARF with pulmonary edema and severely reduced urine output. There were 8 cases (42.1%) with combined complications among the 19 patients. This finding showed a significant difference from the 5 cases (6,4%) in the patients whose creatinine level have not increased over 2.0 mg/㎗. The mortalities are different as 1.3% to 10.5%. The risk factors that are related with postoperative serum creatinine increment over 2.0 mg/㎗ are diabetes, the history of previous serum creatinine over 2.0 mg/㎗ and left ventricular ejection fraction. Conclusion: Postoperative ARF after the on-pump CABG is related with preoperative diabetes, the history of previous serum creatinine over 2,0 mg/㎗ and left ventricular ejection fraction. Postoperative ARF could De the reason for increased rate of complications and mortality after on-pump CABG. Therefore, in the patients with these risk factors, the efforts to prevent postoperative ARF like off-pump CABG should be considered.

• Journal of Chest Surgery
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• v.40 no.6 s.275
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• pp.414-419
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• 2007

Background: Replacing the ascending aorta is a standard surgical option for treating acute type A aortic dissection. But replacing the aortic arch has recently been reported as an acceptable procedure for this disease. We compared the effects of aortic arch replacement for treating acute type A aortic dissection with the effects of ascending aortic replacement. Material and Method: From 2002 to 2006, 25 patients undewent surgical treatment for acute type A aortic dissection, 12 patients undewent ascending aortic replacement and 13 patients underwent aortic arch replacement. Among the aortic arch group, an additional distal stent-graft was inserted during the operation in 5 patients. 19 patients (11 arch replaced patients and 8 ascending aortic replaced patients) were followed up at the out patient clinic for an average of $756{\pm}373$ days. All the patients undewent CT scanning and we analyzed their distal aortic segments. Result: 4 patients who underwent ascending aortic replacement died, so the overall mortality rate was 16%. Among the 11 long term followed-up arch replacement patients, 2 patients (18.1 %) developed distal aortic dilatation and one of them underwent thoracoabdominal aortic replacement later on. However, among the 8 the ascending aortic replaced patients, 5 patients (62.5%) developed distal aortic dilatation. Conclusion: Aortic arch replacement is one of the safe options for treating acute type A aortic dissection. Aortic arch replacement for treating acute type A aortic dissection could contribute to a reduced distal aortic dilatation rate and fewer secondary aortic procedures.

• Journal of Chest Surgery
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• v.44 no.5
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• pp.348-354
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• 2011

Background: Traumatic rupture of the diaphragm is an unusual type of trauma. In addition, it is difficult to diagnose because it can be accompanied by injuries to other organs. If it is not detected early, the mortality rate can increase due to serious complications. Diaphragmatic rupture is an important indicator of the severity of the trauma. The aim of this study was to investigate the factors affecting the incidence of complications and mortality in patients who had surgery to treat traumatic rupture of the diaphragm. Materials and Methods: The subjects were patients who had undergone a diaphragmatic rupture by blunt trauma or stab wounds except patients who were transferred to other hospitals within 3 days of hospitalization, from January 2000 to December 2007. This study was a retrospective study. 43 patients were hospitalized, and 40 patients were included during the study period. Among them, 28 were male, 12 were female, and the average age was 42 (from 18 to 80). Outcome predictive factors including hypoxia, ventilator application days, revised trauma score (RTS), injury severity score (ISS), age, herniated organs, complications, and the mortality rate were investigated. Results: Causes of trauma included motor vehicle crashes for 20 patients (50%), falls for 10 (25%), stab wounds for 8 (20%), and agricultural machinery accidents for 2 (5%). Most of the patients (36 patients; 90%) had wound sites on the left. Diagnosis was performed within 12 hours for most patients. The diaphragmatic rupture was diagnosed preoperatively in 27 patients (70%) and in 12 patients (30%) during other surgeries. For surgical treatment, thoracotomy was performed in 14 patients (35%), laparotomy in 11 (27.5%), and a surgery combining thoracotomy and laparotomy in 15 patients (37.5%). Herniated organs in the thoracic cavity included the stomach for 23 patients (57.5%), the omentum for 15 patients (37.5%), the colon for 10 patients (25%), and the spleen for 6 patients (15%). Accompanying surgeries included splenectomy for 13 patients (32.5%), lung suture for 6 patients (15%), and liver suture for 5 patients (12.5%). The average hospital stay was $47.80{\pm}56.72$ days, and the period of ventilation was $3.90{\pm}5.8$ days. The average ISS was $35.90{\pm}16.81$ (11~75), and the average RTS was $6.46{\pm}1.88$ (1.02~7.84). The mortality rate was 17.5% (7 patients). Factors affecting complications were stomach hernia and age. Factors affecting the mortality rate were ISS and RTS. Conclusion: There are no typical symptoms of the traumatic rupture of the diaphragm by blunt trauma. Nor are there any special methods of diagnosis; in fact, it is difficult to diagnose because it accompanies injuries to other organs. Stab wounds are also not easy to diagnose, though they are relatively easy to diagnose compared to blunt trauma because the accompanying injuries are more limited. Suture of the diaphragm can be performed through the chest, the abdomen, or the thoracoabdomen. These surgical methods are chosen based on accompanying organ injuries. When there are many organ injuries, there are a great number of complications. Significant factors affecting the complication rate were stomach hernia and age. ISS and RTS were significant as factors affecting the mortality rate. In the case of severe trauma such as pelvic fractures, frequent physical examinations and chest X-rays are necessary to confirm traumatic rupture of the diaphragm because it does not have specific symptoms, and there are no clear diagnosis methods. Complications and the mortality rate should be reduced with early diagnosis and with treatment by confirming diaphragmatic rupture in the thoracic cavity and the abdomen during surgery.

• Journal of Chest Surgery
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• v.42 no.6
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• pp.685-695
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• 2009

Background: Calcification is the most frequent cause of clinical failure of bioprosthetic tissues that are fabricated from Glutaraldehyde (GA)-fixed porcine valve or bovine pericardium. We recently used a multi-factorial approach of employing different mechanisms to investigate how to reduce the calcification of bioprosthetic tissues. The purpose of the present study was to evaluate the synchronized synergism using ethanol, L-lysine and $NaBH_4$ in glutaraldehyde treated porcine pericardium from the standpoint of calcification and tissue elasticity. Material and Method: Porcine pericardium was fixed with 0.625% GA (commercial fixation). An interim step of ethanol (80%; 1 day at room temperature) or L-lysine (0.1 M; 2 days at $37^{\circ}C$) or $NaBH_4$ (0.1 M; 2 days at room temperature) was followed by completion of the GA fixation (2 days at $4^{\circ}C$ and 7 days at room temperature). The tensile strength and thickness of the samples were measured. The treated pericardiums were implanted subcutaneously into three-week old Sprague-Dawley rats for 8 weeks. The calcium content was assessed by atomic absorption spectroscopy and the histology of the samples. Result: The amount of calcium in the pericardium pretreated with ethanol (13.6${\pm}$10.0 ug/mg, p=0.008), L-lysine (15.3${\pm}$1.0 ug/mg, p=0.002) and both (16.1${\pm}$11.1 ug/mg, p=0.012) was significantly reduced compared with the control (51.2${\pm}$8.5 ug/mg). However, $NaBH_4$ pretreatment (65.7${\pm}$61.8 ug/mg, p=0.653) and combined pretreatment that including ethanol, L-lysine and $NaBH_4$ (92.9${\pm}$58.3 ug/mg, p=0.288) were not significantly different from the controls(51.2${\pm}$8.5 ug/mg). Both the combined pretreatment using ethanol and L-lysine (7.60${\pm}$1.55, p=0.76) and the combined pretreatment that included ethanol, L-lysine and $NaBH_4$ (7.47${\pm}$1.85, p=0.33) increased the tensile strength/thickness ratio compared with that of the controls (4.75${\pm}$1.88). Conclusion: The combined pretreatment using ethanol and L-lysine seemed to decrease the calcification of porcine pericardium fixed with glutaraldehyde, as compared to single pretreatment, and it increase the tissue elasticity, but to the degree that showed synchronized synergism. $NaBH_4$ pretreatment seemed to increase the calcification of porcine pericardium, irrespective of whether single or combined pretreatment was used.

• Journal of Korea Water Resources Association
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• v.50 no.11
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• pp.715-723
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• 2017

Extracellular Polymeric Substances (EPS) in the water environment assemble fine, colloidal particles, such as clays, microorganisms and biomass, in large flocs, which are eventually subject to sedimentation and deposition and determine water/sediment quality and quantity. This study hence aimed to investigate the way that water and colloidal chemistry affects EPS-mediated flocculation of colloidal particles, using a jar-test experiment. Especially, ionic strength, divalent cation and humic substances concentrations were selected as experimental variables in the jar-test experiments, to elucidate their effects on EPS-mediated flocculation. A higher ionic strength increased flocculation capability, reducing electrostatic repulsion between EPS-attached colloidal particles and enhancing particle aggregation. 0.1 M NaCl ionic strength had higher flocculation capability, with 3 times larger floc size and 2.5 times lower suspended solid concentration, than 0.001 M NaCl. Divalent cations, such as $Ca^{2+}$, built divalent cationic bridges between colloidal particles and EPS (i.e., $colloid-Ca^{2+}-EPS$ or $EPS-Ca^{2+}-EPS$) and hence made colloidal particles to build into large, settelable flocs. A small $Ca^{2+}$ concentration enhanced flocculation capability, reducing suspended solid concentration 20 times lower than the initial dosed concentration. However, humic substances, adsorbed on colloidal particles, reduced flocculation, because they blocked EPS adsorption on colloidal particles and increased negative charges and electrostatic repulsion of colloidal particles. Suspended solid concentration in the tests with humic substances remained as high as the initial dosed concentration, indicating stabilization rather than flocculation. Findings about EPS-mediated flocculation in this research will be used for better understanding the fate and transport of colloidal particles in the water environment and for developing the best management practices for water/sediment quality.