Dechromization and dealumination kinetics in process of Na_2CO_3-roasting pretreatment of laterite ores

A novel process was proposed for the activation pretreatment of limonitic laterite ores by Na2CO3 roasting. Dechromization and dealumination kinetics of the laterite ores and the effect of particle size, Na2CO3-ore mass ratio, and roasting temperature on Cr and Al extraction were studied. Experimental results indicate that the extraction rates of Cr and Al are up to 99%and 82%, respectively, under the optimal particle size of 44–74μm, Na2CO3-to-ore mass ratio of 0.6：1, and temperature of 1000 ℃. Dechromization within the range of 600–800 oC is controlled by the diffusion through the product layer with an apparent activation energy of 3.9 kJ/mol, and that it is controlled by the chemical reaction at the surface within the range of 900–1100 ℃ with an apparent activation energy of 54.3 kJ/mol. Besides, the Avrami diffusion controlled model with on apparent activation energy of 16.4 kJ/mol is most applicable for dealumination. Furthermore, 96.8%Ni and 95.6%Co could be extracted from the alkali-roasting residues in the subsequent pressure acid leaching process.

Performance analysis of three-stage liquid desiccant deep dehumidification processor driven by heat pump

A new type of a heat pump driven three-stage lithium bromide liquid desiccant deep dehumidification processor is presented,which can dehumidify the outdoor humid air to a rather dry state,even when there is no available indoor exhaust air.The test results show that with an outdoor air temperature of 28 to 31 ℃ and an outdoor air humidity ratio of 11 to 14 g/kg,the supply air temperature and the supply air humidity ratio are 1.6 to 2.6 ℃ and 2.6 to 3.0 g/kg,respectively,and the coefficient of performance（COP）of the processor is 1.8.During the test,a liquid pipeline link problem leading to mixture losses of hot and cold liquid desiccants is found.These pipelines are modified.Then,the performance of the modified processor is investigated.And the experimental results show that with an outdoor air temperature of 25 to 32 ℃ and an outdoor air humidity ratio of 18 to 21 g/kg,the supply air temperature and the supply air humidity ratio are 3.2 to 4.0 ℃ and 3.4 to 3.6 g/kg,respectively,and the COP is 2.8.Finally,a mathematical model of the processor is established.The comparison of the simulation results and the test results of the processor exhibits that the pipeline modification improves the performance by about 20%.

Numerical study on dehumidifying process in falling film dehumidifier

A counter flow model of simultaneous heat and mass transfer of a vapor absorption process in a falling film dehumidifier is developed. The governing equations with appropriate boundaries and interfacial conditions describing the dehumidifying process are set up. Calcium chloride is applied as the desiccant. The dehumidifying process between falling liquid desiccant film and process air is analyzed and calculated by the control volume approach. Velocity field, temperature distribution and outlet parameters for both the process air and desiccant solution are obtained. The effects of inlet conditions and vertical wall height on the dehumidification process are also predicted. The results show that the humidity ratio, temperature and mass fraction of salt decrease rapidly at the inlet region but slowly at the outlet region along the vertical wall height. The dehumidification processes can be enhanced by increasing the vertical wall height, desiccant solution flow rates or inlet salt concentration in the desiccant solution, respectively. Similarly, the dehumidification process can be improved by decreasing the inlet humidity ratio or flow rates of the process air. The obtained results can improve the performance of the dehumidifier and provide the theoretical basis for the optimization design, and the ooeration and modulation of the solar liquid desiccant air-conditioning systems.

“除非”意义探究

现代汉语中,"只有"和"除了"是"除非"通常具有的义项,语言学界对"除非"意义的理解仍然存在较大分歧。本文在充分总结前人理论的基础上,从焦点理论和预设理论的角度,尝试对"除非"一词进行阐释。

Deep removal of copper from nickel electrolyte using manganese sulfide

Copper is difficult to separate from nickel electrolyte due to low concentration of copper (0.53 g/L) with high concentration of nickel (75 g/L). Manganese sulfide (MnS) was used to deeply remove copper from the electrolyte. Experimental results show that the concentration of copper (ρ(Cu)) decreases from 530 to 3 mg/L and the mass ratio of copper to nickel (RCu/Ni) in the residue reaches above 15 when the MnS dosage is 1.4 times the theoretical valueDt,MnS (Dt,MnS=0.74 g) and the pH value of electrolyte is 4?5 with reaction time more than 60 min at temperatures above 60 °C. The concentration of newly generated Mn2+(ρ(Mn)) in the solution is also reduced to 3 mg/L by the oxidation reaction. The values ofρ(Cu),ρ(Mn)andRCu/Ni meet the requirements of copper removal from the electrolyte. It is shown that MnS can be considered a highly effective decoppering reagent.

Surgical Resection of Right or Total Caudate Lobe of the Liver Including the Paracaval Portion

Objective To explore the method for and experience of the right or total caudate lobectomies including the paracaval portion. Methods The right posterior approach was employed for right caudate lobectomy and the left lateral approach for total caudate lobectomy. Prior to liver parenchymal transection, dissection was made to separate the caudate lobe and the tumor from the retrohepatic inferior vena cava (IVC). The transection was carried out by forceps and finger fracture with or without some kind of hepatic vascular occlusion. Results A total of 7 right and 6 total caudate lobectomies were performed, all including resection of the paracaval portion. There were no operative deaths or severe complications. The mean intraoperative blood loss was 896 ml (range: 250–2 000 ml). Among the 13 hepatectomies, 10 were done under portal triad clamping with a mean clamp time of 25 min (range: 10–83 min). There was a mean postoperative hospital stay of 12 days (range: 9–22 days). Conclusion Athough deeply located and in close proximity to the trunk of the main hepatic veins and the portal pedicle, the caudate lobe including paracaval portion can be safely resected either alone or combined with liver resection. Key words hepatectomy - liver neoplasms - inferior vena cava-surgery

Bilateral liver resection for bilateral intrahepatic stones

AIM: To evaluate the shortand long-term outcomes of bilateral liver resection for bilateral intrahepatic stones. METHODS: We reviewed retrospectively 101 consecutive patients with bilateral intrahepatic stones who underwent bilateral liver resection in the past 10 years. The shortand long-term outcomes of the patients were analyzed. The Cox proportional hazards model was used to identify the risk factors related to stone recurrence. RESULTS: There was no surgical mortality in this group of patients. The surgical morbidity was 28.7%. Stone clearance rate after hepatectomy was 84.2% and final clearance rate was 95.0% following postoperative choledochoscopic lithotripsy. The stone recurrence rate was 7.9% and the occurrence of postoperative cholangitis was 6.5% in a median follow-up period of 54 mo. The Cox proportional hazards model indicated that liver resection range, less than the range of stone distribution (P = 0.015, OR = 2.152) was an independent risk factor linked to stone recurrence. CONCLUSION: Bilateral liver resection is safe and its shortand long-term outcomes are satisfactory for bilateral intrahepatic stones.

Portal vein embolization for induction of selective hepatic hypertrophy prior to major hepatectomy: rationale,techniques, outcomes and future directions

The ability to modulate the future liver remnant(FLR) is a key component of modern oncologic hepatobiliary surgery practice and has extended surgical candidacy for patients who may have been previously thought unable to survive liver resection. Multiple techniques have been developed to augment the FLR including portal vein embolization(PVE), associating liver partition and portal vein ligation(ALPPS), and the recently reported transhepatic liver venous deprivation(LVD). PVE is a well-established means to improve the safety of liver resection by redirecting blood flow to the FLR in an effort to selectively hypertrophy and ultimately improve functional reserve of the FLR. This article discusses the current practice of PVE with focus on summarizing the large number of published reports from which outcomes based practices have been developed. Both technical aspects of PVE including volumetry, approaches, and embolization agents; and clinical aspects of PVE including data supporting indications, and its role in conjunction with chemotherapy and transarterial embolization will be highlighted. PVE remains an important aspect of oncologic care; in large part due to the substantial foundation of information available demonstrating its clear clinical benefit for hepatic resection candidates with small anticipated FLRs.

Natural orifice transluminal endoscopic wedge hepatic resection with a water-jet hybrid knife in a non-survival porcine model

AIM: To explore the feasibility of a water-jet hybrid knife to facilitate wedge hepatic resection using a natural orifice transluminal endoscopic surgery (NOTES) approach in a non-survival porcine model. METHODS: The Erbe Jet2 water-jet system allows a needleless, tissue-selective hydro-dissection with a pre-selected pressure. Using this system, wedge hepatic resection was performed through three natural routes (trans-anal, trans-vaginal and trans-umbilical) in three female pigs weighing 35 kg under general anesthesia. Entry into the peritoneal cavity was via a 15-mm incision using a hook knife. The targeted liver segment was marked by an APC probe, followed by wedge hepatic resection performed using a water-jet hybrid knife with the aid of a 4-mm transparent distance soft cap mounted onto the tip of the endoscope for holding up the desired plane. The exposed vascular and ductal structures were clipped with Endoclips. Hemostasis was applied to the bleeding cut edges of the liver parenchyma by electrocautery. After the procedure, the incision site was left open, and the animal was euthanized followed by necropsy. RESULTS: Using the Erbe Jet2 water-jet system, trans-anal and trans-vaginal wedge hepatic resection was successfully performed in two pigs without laparoscopic assistance. Trans-umbilical attempt failed due to an unstable operating platform. The incision for peritoneal entry took 1 min, and about 2 h was spent on excision of the liver tissue. The intra-operative blood loss ranged from 100 to 250 mL. Microscopically, the hydro-dissections were relatively precise and gentle, preserving most vessels. CONCLUSION: The Erbe Jet2 water-jet system can safely accomplish non-anatomic wedge hepatic resection in NOTES, which deserves further studies to shorten the dissection time.

Simple and reproducible hepatectomy in the mouse using the clip technique

AIM: To investigate the reliability of massive hepatectomy models by using clip techniques. METHODS: We analyzed anatomical findings in 100 mice following massive hepatectomy induced by liver reduction > 70%. The impact of various factors in the different models was also analyzed, including learning curves, operative time, survival curves, and histopathological findings.RESULTS: According to anatomical results, models with 75%, 80%, and 90% hepatectomy produced massive hepatectomy. Learning curves and operative times were most optimal with the clip technique. Each hepatectomy performed using the clip technique produced a reasonable survival curve, and there were no differences in histopathological findings between the suture and clip techniques. CONCLUSION: Massive hepatectomy by the clip technique is simple and can provide reliable and relevant data.

Prospective randomized controlled trial investigating the type of sutures used during hepatectomy

AIM: To determine whether absorbable sutures or non-absorbable sutures are better in preventing surgical site infection (SSI), in this paper we discuss the results of a randomized clinical trial which examined the type of sutures used during hepatectomy. METHODS: All hepatic resections performed from January 2007 to November 2008 at the Department of Surgery at Iizuka Hospital in Japan were included in this study. There were 125 patients randomly assigned to an absorbable sutures (Vicryl) group or non-absorbable sutures (Silk) group. RESULTS: SSI was observed in 13.6% (17/125) patients participating in this study, 11.3% in the Vicryl group and 15.8% in the Silk group. Incisional SSI including superficial and deep SSI, was observed in 8% of the Vicryl group and 9.5% of the Silk group. Organ/ space SSI was observed in 3.2% of the Vicryl group and 6.0% of the Silk group. There were no significant differences, but among the patients with SSI, the period for recovery was significantly shorter for the Vicryl group compared to the Silk group.CONCLUSION: The incidence of SSI in patients receiving absorbable sutures and silk sutures is not significantly different in this randomized controlled study; however, the period for recovery in patients with SSI was significantly shorter for absorbable sutures.

Operating performance of novel reverse-cycle defrosting method based on thermal energy storage for air source heat pump

To solve the fundamental problem of insufficient heat available during defrosting while ensuring the efficient and safe system operation for air-source heat pumps (ASHPs). A novel reverse-cycle defrosting (NRCD) method based on thermal energy storage to eliminate frost off the outdoor coil surface was developed. Comparative experiments using both the stand reverse cycle defrosting (SRCD) method and the NRCD method were carried out on an experimental ASHP unit with a nominal 2.5 kW heating capacity. The results indicate that during defrosting operation, using the NRCD method improves discharge and suction pressures by 0.24 MPa and 0.19 MPa, respectively, shortens defrosting duration by 60%, and reduces the defrosting energy consumption by 48.1% in the experimental environment, compared with those by the use of SRCD method. Therefore, using the NRCD method can shorten the defrosting duration, improve the indoor thermal comfort, and reduce the defrosting energy consumption in defrosting.

Micrometastasis in surrounding liver and the minimal length of resection margin of primary liver cancer

AIM： To describe the distribution of micrometastases in the surrounding liver of patients with primary liver cancer （PLC）, and to describe the minimal length of resection margin （RM） for hepatectomy. METHODS： From November 2001 to March 2003, 120 histologically verfied PLC patients without macroscopic tumor thrombi or macrosatellites or extrahepatic metastases underwent curative hepatectomy. Six hundreds and twenty-nine routine pathological sections from these patients were re-examined retrospectively by light microscopy. In the prospective study, curative hepatectomy was performed from November 2001 to March 2003 for 76 histologically verfied PLC patients without definite macroscopic tumor thrombi or macrosatellites or extrahepatic metastases in preoperative imaging. Six hundreds and forty-five pathological sections from these patients were examined by light microscopy. The resected liver specimens were minutely examined to measure the resection margin and to detect the number of daughter tumor nodules, dominant lesions, and macroscopic tumor thrombi inside the lumens of the major venous system. The paraffin sections were microscopically examined to detect the microsatellites, microscopic tumor thrombi, fibrosis tumor capsules, as well as capsule invasion and the distance of histological spread of the micrometastases. RESULTS： In the retrospective study, 70 micrometastases were found in surrounding liver in 26 of the 120 cases （21.7%）. The farthest distance of histological micrometastasis was 3.5 mm, 5.3 mm and 6.0 mm in 95%, 99% and 100% cases, respectively. Macroscopic tumor thrornbi or rnacrosatellites were observed in 18 of 76 cases, and 149 rnicrometastases were found in the surrounding live in 25 （43.1%） of 58 cases with no macroscopic tumor thrombi. The farthest distance of histological micrometastasis was 4.5 mm, 5.5 mm and 6.0 mm in 95%, 99% and 100% cases, respectively. Two hundred and sixty-seven rnicrometastases were found in surrounding liver in 14 （77.8%） out of 18 cases with macroscopic tumor thrombi or macrosatellites. The farthest distance of histological micrometastasis was 18.5 mm, 18.5 mm and 19.0 mm in 95%, 99% and 100% cases, respectively. CONCLUSION： The required minimal length of RM is 5.5 mm and 6 mm respectively to achieve 99% and 100% rnicrometastasis clearance in surrounding liver of PLC patients without macroscopic tumor thrornbi or rnacrosatellites, and should be greater than 18.5 mm to obtain 99% rnicrometastasis clearance in surrounding liver of patients with macroscopic tumor thrornbi or rnacrosatellites.

Improvement of conventional liquid desiccant dehumidification technology

A new system of liquid desiccant dehumidification,called ultrasound atomization dehumidification system,is proposed.In this system,a packed bed is replaced by ultrasound atomization technology,so high resistance and liquid desiccant consumption caused by the packed bed are avoided.A mathematical model is established to predict the efficiency and the liquid consumption of the dehumidification process under ideal conditions.Through comparing the simulation results with the experimental data of a conventional packed-bed dehumidifier,it is found that the liquid desiccant consumption of the conventional packed-bed dehumidifier is much greater than that under ideal conditions.In the proposed system,the dehumidification process occurs on the surfaces of the micron liquid desiccant droplets produced with the irradiation of ultrasound,so there is a greater contact area created with the same quantity of the liquid desiccant;moreover,the power consumption is lower because there are no nozzles and no solution pump.It can be seen that this new system is closer to ideal conditions when compared with the conventional liquid desiccant dehumidification system.

Nitrogen removal by three types of bioretention columns under wetting and drying regimes

The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conventional bioretention column(Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer(Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone(Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH+4—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO-3—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3—N.

Endoscopic Ultrasound-guided drainage of an abdominal fluid collection following Whipple's resection

Percutaneous aspiration and drainage of post-operative abdominal fluid collections is a well established standard technique. However,some fluid collections are not amenable to percutaneous drainage either due to location or the presence of surrounding visceral structures. Endoscopic Ultrasound (EUS) has been widely used for the drainage of pancreatitis-related abdominal fluid collections. However,there are no reports on the use of this technique in the post-operative setting. We report a case where the EUS-guided technique was used to drain a percutaneously inaccessible post-operative collection which had developed after Whipple's resection.

Learning curve of laparoscopy-assisted distal gastrectomy with systemic lymphadenectomy for early gastric cancer

AIM: To evaluate the nature of the 'learning curve' for laparoscopy-assisted distal gastrectomy (LADG) with systemic lymphadenectomy for early gastric cancer. METHODS: The data of 90 consecutive patients with early gastric cancer who underwent LADG with systemic lymphadenectomy between April 2003 and November 2004 were reviewed. The 90 patients were divided into 9 sequential groups of 10 cases in each group and the average operative time of these 9 groups were determined. Other learning indicators, such as transfusion requirements, conversion rates to open surgery, postoperative complication, time to first flatus, and postoperative hospital stay, were evaluated. RESULTS: After the first 10 LADGs, the operative time reached its first plateau (230-240 min/operation) and then reached a second plateau (＜200 min/operation) for the final 30 cases. Although a significant improvement in the operative time was noted after the first 50 cases, there were no significant differences in transfusion requirements, conversion rates to open surgery, postoperative complications, time to first flatus, or postoperative hospital stay between the groups. CONCLUSION: Based on operative time analysis, this study show that experience of 50 cases of LADG with systemic lymphadenectomy for early gastric cancer is required to achieve optimum proficiency.

Hepatoid adenocarcinoma in stomach:a case report

Objective:We reported a case with AFP produced gastric hepatoid adenocarcinoma.Methods:A male patient,77 year-old,was admitted to our hospital due to an unreasonable elevation of serum AFP.The tumors were revealed by PET-CT,but until the tumors were removed during the surgery,we did not recognize the primary lesion was the gastric cancer.Results:Radical distal gastrectomy was performed.The gastric lesion was confirmed by histology as a hepatic adenocarcinoma in its early stage.Conclusion:The rare etiology of the AFP elevation should be kept in mind in clinic,extrahepatic lesions should be excluded.

Pancreaticoduodenectomy for advanced gastric cancer with pancreaticoduodenal region involvement

AIM：To characterize the factors of the improved survival following combined pancreaticoduodenectomy（PD） and gastrectomy for the treatment of advanced gastric cancer with pancreaticoduodenal region involvement.METHODS：From 1995 to 2004,53 patients with primary gastric cancer were diagnosed with synchronous（n = 44） or metachronous（n = 9） pancreaticoduodenal region involvement.Of these,17 patients（32%） underwent total gastrectomy（TG） or distal subtotal gastrectomy（SG） combined with PD simultaneously.The preoperative demographic,clinical information,clinicopathologic features and the surgical results of these 17 patients were considered as factors influencing survival and were analyzed by the Kaplan-Meier method with log-rank comparison.RESULTS：The actual 1-and 3-year survival rates of these 17 patients after resection were 77% and 34%,respectively,and three patients survived for more than 5 years after surgery.The tumor-free resection margin（P = 0.0174） and a well-differentiated histologic type（P = 0.0011） were significant prognostic factors on univariate analysis.No mortality occurred within one mo after operation,postoperative weight loss of different degree was present in all the patients with TG and 12 cases had other complications.There were 9（53%） cases of recurrence in 5-48 mo after operation.The survival rate in the palliative and explorative group was significantly（P = 0.0064） lower than in the combined PD group.CONCLUSION： Judicious use of en bloc PD and gastrectomy and strictly preventing postoperative complications may improve the long-term survival for advanced gastric cancer patients with pancreaticoduodenal region involvement. Well-differentiated histology and negative resection margin are the most important predictors of long survival.

Surgical approaches of resectable synchronous colorectal liver metastases:Timing considerations

AIM: To compare the safety and efficacy of simultaneous versus two stage resection of primary colorectal tumors and liver metastases. METHODS: From January 1996 to May 2004, 103 colorectal tumor patients presented with synchronous liver metastases. Twenty five underwent simultaneous colorectal and liver surgery and 78 underwent liver surgery 1-3 mo after primary colorectal tumor resection. Data were retrospectively analyzed to assess and compare the morbidity and mortality between the surgical strategies. The two groups were comparable regarding the age and sex distribution, the types of liver resection and stage of primary tumors, as well as the number and size of liver metastases. RESULTS: In two-stage procedures more transfusions were required (4 ± 1.5 vs 2 ± 1.8, pRBCs, P < 0.05). Chest infection was increased after the two-stage approach (26% vs 17%, P < 0.05). The two-stage procedure was also associated with longer hospitalization (20 ± 8 vs 12 ± 6 d, P < 0.05). Five year survival in both groups was similar (28% vs 31%). No hospital mortality occurred in our series. CONCLUSION: Synchronous colorectal liver metastases can be safely treated simultaneously with the primary tumor. Liver resection should be prioritized over colon resection. It is advisable that complex liver resections with marginal liver residual volume should be dealt with at a later stage.