Potassium Amyl Xanthate (PAX) as an alternative organic reactive for mercury removal from cyanidation process of amalgamation tailing.

Mercury is the heavy metal that is most difficult to remove from cyanide solution. This situation brings with it many environmental, health and economic problems. This study aims to effectively utilize xanthate by presenting a new strategy for purifying mercury in the cyanidation process of amalgamation residues. In the study, the removal of mercury by precipitation using PAX from cyanidation leach solutions of a well-characterized amalgamation residue was investigated. The dosage of the precipitation reagent is the most important parameter in the removal of mercury. The mercury removal efficiency increases with the increase in the PAX/Hg ratio, and when the removal ratio is 60, the precipitation efficiency reaches a value of 66.7%. Applying coagulation and flocculation procedures after the precipitation process increases the mercury removal efficiency. It is seen that with this application, mercury can be removed with an efficiency of 95.6% at the same reagent rate. With this application, the particle sizes of the precipitates are enlarged and their filtration properties are improved. It has also been determined that the precipitates formed are in the form of HgS, a stable mercury compound. These results indicate that mercury can be effectively removed in its steady state. It was found that the concentration of Au and Cu did not change significantly, while the concentration of Ag decreased during the precipitation processes.

Fe-based layered double hydroxides for removing arsenic from water: sorption-desorption-regeneration.

Since the presence of arsenic in the waters of the world causes serious health effects on people, it is very important to remove it. Layered double hydroxides have a high surface area and high anion exchange capacity, and because of this feature, it is a potential adsorbent to remove arsenic. For regeneration and reuse of adsorbents, researchers in some limited studies have used agents such as acids and alkalis. Media replacement accounts for approximately 80% of the total operational and maintenance costs. In this paper, an adsorption/desorption/regeneration study was carried out with MgFeHT to determine the desorption properties of the adsorbent and to examine its reusability. The best alkaline desorption solution was determined from two different alkaline solutions: NaOH and KH2PO4. As(V) adsorption capacity of the MgFeHT at different pH (3-12) using the arsenic aqueous solution (with 2,000 µg As(V)/L) was evaluated. For the adsorption process, the experimental data are fitted well with the pseudo-second-order kinetic model and the Langmuir model. Moreover, the concentration of 2,000 µg/L arsenic was reduced to below the legal limit determined by the WHO (<10 µg/L). The regeneration studies were conducted on the adsorptive media used in the arsenic removal system. The regeneration efficiency of As(V) was maintained 98.5% for four regeneration cycles using 0.5 M NaOH. MgFeHT was successfully regenerated with an aqueous solution of NaOH and was reused with a small loss of sorption efficiency.

Arsenic removal from groundwater in Kütahya, Turkey, by novel calcined modified hydrotalcite.

Since arsenic is highly toxic and carcinogenic, it now causes serious health problems all over the world. Therefore, there is an urgent need to develop new techniques that are cost-effective and easily applicable to remove arsenic from contaminated waters. Layer double hydroxides have the potential to be a good adsorbent to remove arsenic from contaminated waters due to high surface area and high anion exchange capacity. In this paper, arsenic removal from water by calcined Fe-hydrotalcite (CFeHT) known as layered double hydroxide and prepared synthetically with coprecipitation method was researched. The study brings out that the effect of initial solution pH values was limited for the adsorption. The experimental study indicates that the adsorption of arsenic rapidly occured in comparison with other studies. It was determined that the pseudo-second-order kinetic model was more suitable than the first order. In isotherm studies, it was seen that the experimental data were compatible with Langmuir model. In this study was determined that CFeHT has a high arsenic removal potential. And also the concentration of the arsenic solution (600 µg/L) has been reduced below the allowable value by the World Health Organization (< 10 µg/L). The desorption test indicates that the desorption ratio of As(V) was obtained as 72.7.

Safety Pericardiocentesis with Fluoroscopy Following Cardiac Surgery.

PURPOSE: In the treatment of the postsurgical pericardial effusions via pericardiocentesis, determination of the puncture site might be difficult. Contrast echocardiography may not be efficient due to surgical artefacts and pulmonary problems and therefore may lead to inaccurate evaluation. Alternative imaging methods might be helpful to perform the pericardiocentesis with decreased complications. METHODS: We retrospectively analyzed the patients who had undergone pericardiocentesis in our department from January 2008 through April 2018. The procedure was performed in slightly semi-seated position with the guidance of the echocardiography and fluoroscopy. Following the catheterization, percutaneous drainage was performed. RESULTS: There were 63 patients needed intervention due to pericardial effusion. 67% of the patients were using warfarin and the next patients were using acetyl salicylic acid and/or clopidogrel. All effusions were in the posterolateral localization. The mean volume of aspirated pericardial fluid was 404 ± 173 mL (150-980 mL). Control echocardiograms showed that almost all fluid was drained in all patients and there were no procedural or follow-up complications. CONCLUSION: In the treatment of postoperative pericardial effusion, fluoroscopy is an alternative method to locate the catheter accurately in challenging situations following cardiac surgery. Thus, procedural risk minimizes and drainage of pericardial fluid is performed safely.

Our experiences on endovascular and hybrid treatment of peripheral arterial diseases.

BACKGROUND: This study aims to present our experiences on endovascular and hybrid treatment of peripheral arterial diseases. METHODS: Between March 2008 and April 2016, 86 patients who underwent endovascular treatment and 17 patients who underwent hybrid treatment for peripheral arterial disease in our clinic were retrospectively analyzed. The treatment approaches, success of treatments, complications and outcomes of these patients were studied. RESULTS: No mortality was seen during the procedures. Following the procedure, the patients were hospitalized in the intensive care unit under standard heparin treatment for six hours at least. Anticoagulation was maintained with low-molecular-weighted heparin for three days, followed by dual oral antiaggregant (acetylsalicylic acid 100 mg + clopidogrel 75 mg). Repeated Doppler ultrasonography revealed no in-stent thrombosis or restenosis at the site of ballooning during hospitalization. None of the patients with normal renal functions preoperatively experienced severe renal failure. Although nearly all femorodistal interventions were performed in the antegrade way, none of the patients had bleeding complications at the site of intervention. All patients were discharged within 1 to 16 days. CONCLUSION: Endovascular and hybrid modalities are safe and comfortable in the treatment of peripheral arterial diseases for vascular surgeons having a hybrid room.

Removal of broken catheter piece with snare device during endovascular treatment of post-traumatic brachial artery pseudo-aneurysm.

Post-traumatic pseudo-aneurysm is a rare complication of penetrating vascular injury. Endovascular stent implantation has become an alternative approach in the management of this pathology. In our case, we present a brachial artery pseudo-aneurysm that was treated with endovascular stent implantation, and removal of a broken catheter part with a three-dimensional snare device.

Coronary artery bypass grafting following simultaneous treatment of abdominal aortic aneurysm and peripheral arterial disease.

Atherosclerosis might affect all arterial segments of the vascular system, thus peripheral arterial disease (PAD) accompanying coronary artery disease (CAD) is not uncommon. In addition to this coexistence, abdominal aortic aneurysm (AAA) is frequently associated with CAD. Although treatment strategies of CAD and PAD or CAD and AAA has been reported previously, treatment of these three pathologies has not been reported. The management of a therapeutic strategy is important for avoiding perioperative mortality and morbidity in CAD associated with AAA and PAD. We are reporting our simultaneous treatment strategy of three pathologies with endovascular AAA repair, stent implantation into the superficial femoral artery (SFA) and coronary artery bypass grafting (CABG).

Comparison of conventional technique and ultrasonographic mapping in saphenous vein harvesting.

BACKGROUND: Saphenous vein mapping provides accurate identification of the graft diameter, location of the harvest side, and quality of graft and also led to a selective leg skin incision. In this article, we aimed to compare patients who underwent coronary artery bypass graft (CABG) surgery with or without vein mapping. METHODS: Patients who underwent CABG surgery with saphenous vein grafts (SVG) between January 2005 and January 2010 in our service were analyzed retrospectively. One hundred seventy-eight 178 SVGs were harvested with classical methods (Group A), and 136 SVGs were harvested after Doppler ultrasonography (USG) mapping (Group B). RESULTS: In Group A, 6.7% of patients needed additional incisions for graft harvesting than planned before CABG surgery due to unsuitable vein grafts. In Group B, SVGs were harvested from left lower extremity in 16 patients, and the saphenous vein was not suitable for grafting in 1 patient due to Doppler examination. In the postoperative period, complications at the incision site were reduced in Group B. CONCLUSION: Preoperative vein mapping for harvesting SVGs is an effective method in reducing wound site complications, hospital stay, and hospital costs and in increasing patient comfort and satisfaction.

Four different strategies for repair of aortic coarctation accompanied by cardiac lesions.

OBJECTIVES: Coarctation accompanied by cardiac lesions is a complex clinical situation due to the presence of two different pathologies that necessitate surgical treatment. An individual strategy, according to the severity of the disease, is important to reduce perioperative mortality and morbidity. METHODS: We report here on 25 patients with coarctation accompanied by cardiac lesions who were treated by various surgical approaches. Coarctation and associated disease were treated in 14 patients in a single stage by an ascending-to-descending bypass (n = 11) or by a hybrid procedure (n = 3). The remaining 11 patients underwent a two-stage operation for their treatment. Six of these 11 patients who had coronary artery disease or signs of congestive heart failure were first operated for their cardiac disease, whereas in the remaining five patients, who did not have any congestive signs, coarctation repair was performed first. RESULTS: All the patients were male, between the ages of 20 and 24 years, except for one 45-year-old woman. The mean cross-clamp times, cardiopulmonary bypass times and operation times were 52 ± 14.5, 102.3 ± 28.5 and 174 ± 24.8 min in the extra-anatomical bypass group; 29.8 ± 11.7, 55.5 ± 17.6 and 116 ± 22 min in the two-stage groups and 49 ± 19.8, 63 ± 18.7 and 159 ± 21.3 min in the hybrid patients, respectively. One patient who underwent extra-anatomical bypass died on the 14th postoperative day. There were no events during the follow-up period for the other patients. Also, there were no gradients between the extremities and no graft-related complications. CONCLUSIONS: As a consequence of the progress in the development of endovascular techniques, hybrid treatment is becoming a more popular option for the treatment of coarctation accompanied by cardiac diseases. Two-stage procedures and extra-anatomical bypass might be alternative techniques if endovascular procedures are contraindicated or failing.

Long-term results of the single-patch repair technique for sinus venosus atrial septal defects.

BACKGROUND: Anomalous pulmonary venous drainage commonly accompanies sinus venosus atrial septal defects (SVASDs). Many techniques have been reported for avoiding postoperative complications, such as narrowing of the superior vena cava (SVC) or the pulmonary system, and arrhythmia. We perform a single V-Y pericardial patch plasty repair technique for SVASDs. The purpose of this study is to report on the long-term results of this surgical technique. METHODS: We retrospectively analyzed patients who had a diagnosis of ASD and who underwent their operations between 2000 and 2010 at the Gulhane Military Medical Academy Haydarpasa Training Hospital. Thirty-nine of the patients had an anomalous pulmonary return, and the single pericardial patch technique had been performed in 32 of these patients. RESULTS: The mean (±SD) postoperative extubation time was 5 ± 1.6 hours. The mean drainage volume was 384 ± 137 mL. All patients were discharged from the hospital at a mean of 4.6 ± 1.1 days after their operation and were prescribed anticoagulants for 3 months. No perioperative or late-term mortality was observed. Patients were followed up for 6 months to 2 years. There were no residual shunts and no stenosis-related findings in the pulmonary venous system or the SVC. CONCLUSION: Use of the single pericardial patch plasty technique might lower complication rates in patients with SVASD, especially those who have not completed their growth.

Reversed C sternotomy versus conventional sternotomy in cardiac surgery.

BACKGROUND: In this study, cardiac surgery with minimally invasive reversed C sternotomy was compared with conventional sternotomy in patients undergoing valve replacement or septal defect repair. METHODS: In this prospective randomized study, 35 patients were assigned into one of two groups for elective cardiac surgery under general anesthesia: Group A (reversed C sternotomy group) and Group B (conventional sternotomy group). Intraoperative variables, intubation time, postoperative drainage volume, pulmonary function tests, sleep quality and quality of life, and requirement for blood transfusion were compared. RESULTS: A significant difference between the two groups was found in blood transfusion requirement, extubation time, and drainage volume. Forced expiratory volume in one second and functional vital capacity were significantly lower in Group B than in Group A at postoperative Month 1. Total sleep component score of Pittsburg Sleep Quality Index in Group B patients was significantly worse at postoperative Month 1. Postoperative assessment of quality of life (physical and mental) also showed a significant difference between the two groups. CONCLUSION: These preliminary findings suggest that creating an access point without compromising the integrity of the sternum seems to be an advantageous and appropriate technique for suitable patients undergoing cardiac surgery.

Conventional versus complete chordal-sparing mitral valve replacement: effects on left ventricular function and end-systolic stress.

BACKGROUND: This study aims to assess the effects of bileaflet preservation versus conventional technique during mitral valve replacement (MVR) on left ventricular functions and end-systolic stress (ESS). METHODS: Between September 2005 and January 2009, sixty-five patients with mitral regurgitation underwent MVR surgery. In a non-randomized fashion, 34 patients had conventional MVR without chordal/leaflet preservation (group I, c-MVR), and 31 had MVR with total chordal/bileaflet preservation (group II, b-MVR). A prospective clinical and echocardiographic follow-up of patients was performed preoperatively, at 3 months and by 1 year postoperatively. RESULTS: Left ventricular end-systolic/end-diastolic dimensions and volumes decreased by 1 year in the b-MVR group. Left ventricular ESS decreased only in the bileaflet sparing MVR group after surgery, and this decrease was significant by 1 year, compared with the c-MVR group (P = 0.008). Left atrial diameter significantly decreased in both groups. Only one patient died, due to posterior wall rupture after a c-MVR procedure. One patient undergoing a b-MVR procedure needed re-operation because of prosthetic valve endocarditis. CONCLUSION: Bileaflet preservation during MVR has a beneficial effect on left ventricular function, compared with conventional MVR. Left ventricular ESS improves after bileaflet-sparing MVR and may be an important indicator of myocardial function after mitral valve surgery.

Natural internal banding in adult patients with a large ventricular septal defect and a preserved pulmonary vascular system.

OBJECTIVE: Hypertrophied anomalous muscle bands (AMBs) in the right ventricular outflow tract (RVOT) may develop in the context of ventricular septal defects (VSDs) and limit persistent pulmonary overflow. In adult patients with a large VSD, persistent AMBs in the RVOT therefore can simulate the role of an externally placed pulmonary artery band. We termed such alterations natural internal bands (NIBs). Our goal was to establish the morphologic nature of the obstructive muscular lesions of the RVOT in patients with a large VSD. METHODS: Patients who underwent operations for a large VSD in our center, which has a high volume of adult patients with congenital defects, were retrospectively reviewed, and the nature of the NIBs in these patients was documented. All patients underwent transthoracic echocardiography and cardiac catheterization evaluations preoperatively and at postoperative month 3. Histopathologic examination of the AMBs was performed. RESULTS: Of 96 adult patients who underwent operations for a large isolated VSD (mean defect size, 16.9 ± 3.5 mm), 16 patients had a hemodynamically significant NIB. Two different patterns of obstruction were found. Ten of the 16 patients revealed an os infundibulum morphology, and 6 patients revealed systolic bulging of the conal septum. Four of the patients with os infundibulum also had classic tetralogy-type septal malalignment. The mean peak systolic gradient on the RVOT was 56.5 ± 17.2 mm Hg and 53.6 ± 12.3 mm Hg in the patients with os infundibulum and in the patients with systolic bulging of the conal septum, respectively. Surgical repair of the VSD was completed successfully in all patients. Resection of the os infundibulum was performed concomitantly in patients with os infundibulum. At the third postoperative month, the mean peak systolic gradient was 16.8 ± 3.5 mm Hg in patients with os infundibulum and 26 ± 5.9 mm Hg (range, 20-35 mm Hg) in patients with systolic septal bulging. CONCLUSIONS: Some mechanisms in adult type VSDs are essential for protecting the pulmonary vasculature. We tried to review these protective mechanisms: hypertrophied AMBs and NIBs.

Utilization of water-reducing admixtures in cemented paste backfill of sulphide-rich mill tailings.

This study presents the effect of three different water-reducing admixtures (WRAs) on the rheological and mechanical properties of cemented paste backfill (CPB) samples. A 28-day strength of > or = 0.7 MPa and the maintenance of the stability (i.e. > or = 0.7 MPa) over 360 days of curing were desired as the design criteria. Ordinary Portland cement (OPC) and Portland composite cement (PCC) were used as binders at 5 wt.% dose. WRAs were initially tested to determine the dosage of a WRA for a required consistency of 7'' for CPB mixtures. A total of 192 CPB samples were then prepared using WRAs. The utilization of WRAs enhanced the flow characteristics of the CPB mixture and allowed to achieve the same consistency at a lower water-to-cement ratio. For OPC, the addition of WRAs appeared to improve the both short- and long-term performance of CPB samples. However, only polycarboxylate-based superplasticiser produced the desired 28-day strength of > or = 0.7 MPa when PCC was used as the binder. These findings suggest that WRAs can be suitably exploited for CPB of sulphide-rich tailings to improve the strength and stability in short and long terms allowing to reduce binder costs in a CPB plant.

Effect of natural pozzolans as mineral admixture on the performance of cemented-paste backfill of sulphide-rich tailings.

This paper presents the effect of the natural pozzolans as mineral additives on the short- and long-term strength and stability performance of cemented paste backfill (CPB) samples. Prior to their use in CPB studies, the natural pozzolans - the volcanic tuffs (Akkus Trass [AT] and Fatsa Trass [FT]) and pumice (KP) - were tested for their pozzolanic characteristics. These tests revealed that the pozzolanic activity of the natural pozzolans is closely inter-related with their content of reactive silica and, accordingly, KP has the highest pozzolanic activity. The addition, or increasing the amount, of natural pozzolans in the binder phase resulted in a slower rate of strength development of CPB samples. The deterioration in stability of CPB samples prepared from Portland cement (PC) alone (i.e. a strength loss of 24.6%) occurred following 56 days. The replacement of PC with FT and AT led to even higher losses in strength. However, the addition of KP (up to 30 wt%) mitigated, to a certain extent, long-term strength and stability problems with the losses in strength of CPB samples consistently lower than 20%. It can be inferred that the performance of the natural pozzolans as a mineral additive in CPB is dependent intimately on their pozzolanic characteristics.

Accessory mitral papillary muscle causing severe aortic insufficiency.

Accessory mitral papillary muscle originating from the interventricular septum is a rare congenital anomaly. A 20-year-old male patient presented with a complaint of exertional dyspnea. On cardiac examination, a grade 3/4 diastolic murmur was heard over the right upper parasternal area, and the apical pulsations were easily palpable over the precordium. Transthoracic echocardiography showed severe aortic regurgitation, dilatation of the left ventricle, and an accessory papillary muscle with its chordae, extending from the interventricular septum to the anterior mitral leaflet in the left ventricular outflow tract (LVOT). There was no mitral regurgitation. Color Doppler imaging showed turbulence set up by the abnormal mitral attachment and an associated mild pressure gradient of 20 mmHg across the LVOT. At surgery for aortic valve replacement, degenerative changes in the aortic leaflets were noted. The accessory papillary muscle was spared to maintain mitral valve functions and an aortic bileaflet mechanical prosthetic valve was implanted. During eight months of follow-up, he was well without any signs of left ventricular systolic dysfunction and mitral regurgitation, with a functioning prosthetic valve.

Leachable characteristics of arsenical borogypsum wastes and their potential use in cement production.

In this study; the potential use of arsenical borogypsum wastes (ABW) as a set retarder in cement industry was investigated. The comparative performances of arsenical borogypsum wastes (ABW) and natural gypsum samples (NG1 and NG2) at different proportions in the range of 3-8 wt % were tested based on compressive strength over 1, 2, 7, and 28 days and setting times. The use of ABW was observed to lead to a somewhat slower rate of development of strength of the mortar samples than those of NG1 and NG2 during the curing period of 7 days. This is the indication of the effectiveness of ABW as a set retarder. The 28-day compressive strength of mortars tended to decrease with the addition or increasing the proportion of ABW, beyond 5 wt % in particular. The data for setting times of the cement products confirmed set retarding characteristics of ABW with an initial setting time of 90-120 min at 3-5 wt % dosage, which conforms to the desired setting time of > or = 60 min for CEM I (42.5 N) type cement (TS EN 197-1). Leachability tests (TCLP and SPLP) have also shown that ABW can be classified as a nonhazardous waste; but it can readily release metals such as As and Mn, in particular, whereas the mortar samples containing ABW-cement clinker present no environmental concern with its remarkably reduced leachability.

Free-floating tumor thrombus in the left atrium associated with non-small cell lung cancer.

A free-floating tumor thrombus in the left atrium is an unusual metastasis of non-small cell lung cancer. Surgical resection of free-floating tumor thrombus prior to adjuvant therapy relieves cardiac symptoms such as exertional dyspnea, and prevents life-threatening complications including systemic embolization, mitral obstruction, or sudden death.