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| 2. |
- Kullman, Eric, et al.
(författare)
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Covered versus uncovered self-expandable nitinol stents in the palliative treatment of malignant distal biliary obstruction: results from a randomized, multicenter study
- 2010
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Ingår i: GASTROINTESTINAL ENDOSCOPY. - : Elsevier Science B. V., Amsterdam. - 0016-5107 .- 1097-6779. ; 72:5, s. 915-923
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Tidskriftsartikel (refereegranskat)abstract
- Background: Covered biliary metal stents have been developed to prevent tumor ingrowth. Previous comparative studies are limited and often include few patients. Objective: To compare differences in stent patency, patient survival, and complication rates between covered and uncovered nitinol stents in patients with malignant biliary obstruction. Design: Randomized, multicenter trial conducted between January 2006 and October 2008. Setting: Ten sites serving a total catchment area of approximately 2.8 million inhabitants. Patients: A total of 400 patients with unresectable distal malignant biliary obstruction. Interventions: ERCP with insertion of covered or uncovered metal stent. Follow-up conducted monthly for symptoms indicating stent obstruction. Main Outcome Measurements: Time to stent failure, survival time, and complication rate. Results: The patient survival times were 116 days (interquartile range 242 days) and 174 days (interquartile range 284 days) in the covered and uncovered stent groups, respectively (P = .320). The first quartile stent patency time was 154 days in the covered stent group and 199 days in the uncovered stent group (P = .326). There was no difference in the incidence of pancreatitis or cholecystitis between the 2 groups. Stent migration occurred in 6 patients (3%) in the covered group and in no patients in the uncovered group (P = .030). Limitations: Randomization was not blinded. Conclusions: There were no significant differences in stent patency time, patient survival time, or complication rates between covered and uncovered nitinol metal stents in the palliative treatment of malignant distal biliary obstruction. However, covered stents migrated significantly more often compared with uncovered stents, and tumor ingrowth was more frequent in uncovered stents.
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| 4. |
- Al-Jaff, Mohammed, et al.
(författare)
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microTaboo : a general and practical solution to the k-disjoint problem
- 2017
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Ingår i: BMC Bioinformatics. - : BIOMED CENTRAL LTD. - 1471-2105. ; 18
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Tidskriftsartikel (refereegranskat)abstract
- Background: A common challenge in bioinformatics is to identify short sub-sequences that are unique in a set of genomes or reference sequences, which can efficiently be achieved by k-mer (k consecutive nucleotides) counting. However, there are several areas that would benefit from a more stringent definition of "unique", requiring that these sub-sequences of length W differ by more than k mismatches (i.e. a Hamming distance greater than k) from any other sub-sequence, which we term the k-disjoint problem. Examples include finding sequences unique to a pathogen for probe-based infection diagnostics; reducing off-target hits for re-sequencing or genome editing; detecting sequence (e.g. phage or viral) insertions; and multiple substitution mutations. Since both sensitivity and specificity are critical, an exhaustive, yet efficient solution is desirable.Results: We present microTaboo, a method that allows for efficient and extensive sequence mining of unique (k-disjoint) sequences of up to 100 nucleotides in length. On a number of simulated and real data sets ranging from microbe-to mammalian-size genomes, we show that microTaboo is able to efficiently find all sub-sequences of a specified length W that do not occur within a threshold of k mismatches in any other sub-sequence. We exemplify that microTaboo has many practical applications, including point substitution detection, sequence insertion detection, padlock probe target search, and candidate CRISPR target mining.Conclusions: microTaboo implements a solution to the k-disjoint problem in an alignment-and assembly free manner. microTaboo is available for Windows, Mac OS X, and Linux, running Java 7 and higher, under the GNU GPLv3 license, at:https://MohammedAlJaff.github.io/microTaboo
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| 5. |
- Awe, Samuel Ayowole, et al.
(författare)
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Formation of sulphur oxyanions and their influence on antimony electrowinning from sulphide electrolytes
- 2013
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 53, s. 39-47
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Tidskriftsartikel (refereegranskat)abstract
- Antimony electrowinning from synthetic alkaline sulphide electrolytes has been studied in a nondiaphragm electrolytic cell. The electrodes were constructed in such a way that the anode produces ten times higher current density than the cathodic current density to promote sulphide oxidation to sulphate at the anode; and simultaneously decreasing the tendency of hydrogen evolution at the cathode. The result revealed that at an anodic current density lower than 1500 A/m2, minute amounts of sulphate ions were formed but when the anode current density increased beyond 1500 A/m2, sulphate formation was promoted. The initial molar concentration ratio between hydroxide and free sulphide ions should be ≥ 10.3 to avoid thiosulphate formation at 2000 A/m2 anodic current density under the conditions used in these experiments. The highest anodic current efficiency obtained based on the amount of sulphate formed was 89%. An increase in the anode current density as well as NaOH concentration enhances the cathodic and anodic current efficiencies with respect to the antimony metal deposited and sulphate ions produced, respectively. Despite the high anodic current densities used, the specific energy of this process ranges from 0.6 to 2.3 kWh/kg which is significantly lower than values reported previously due to the prevention of undesirable sulphur species from being formed. The tests revealed that the concentration of thiosulphate formed during the electrolysis decreased with increasing anode current density and NaOH concentration. Addition of polysulphide from 0 to 30 g/L to the electrolyte decreases the current efficiency from 83% to 32% and correspondingly increases the specific energy from 1.7 to 4.8 kWh/kg. Results showed that a build-up of sulphite and sulphate ions in the solution does not have any detrimental effect on the current efficiency of antimony deposition.
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| 6. |
- Awe, Samuel Ayowole, et al.
(författare)
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Process flowsheet development for recovering antimony from Sb-bearing copper concentrates
- 2013
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Ingår i: Minerals Engineering. - : Elsevier BV. - 0892-6875 .- 1872-9444. ; 49, s. 45-53
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Tidskriftsartikel (refereegranskat)abstract
- The technical feasibility, on laboratory scale, of hydro- and electrometallurgical processes of recovering metallic antimony from an antimony-bearing copper sulphide concentrate has been investigated. The influence of Na2S concentration, temperature and solid concentration was studied during the leaching test while the effect of current density, Na2S concentration, electrolyte temperature and NaOH concentration on antimony electrowinning from alkaline sulphide solutions was investigated. The leaching results showed that antimony dissolution is strongly dependent on the concentration of the leaching reagent as well as the leaching temperature. The antimony content in the concentrate was reduced from 1.7% to less than 0.1% Sb which is desirable for copper metallurgy. Cathode current efficiency is one of the important parameters to evaluate the performance of an electrolytic process. It is revealed in this study that current efficiency of antimony deposition from sulphide electrolytes is highly dependent on the concentration of sodium hydroxide and the current density used. The results illustrate that the combined effect of increasing anode current density (which was 10 times higher than the cathode current density) and NaOH concentration enhanced the current efficiency of the electrolytic process. It was demonstrated that excess free sulphide ions impacts the current efficiency of the process detrimentally. An integrated hydro-/electrometallurgical process flowsheet for antimony removal and recovery from a sulphide copper concentrate was developed.
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| 7. |
- Björnsson, Bergthor, et al.
(författare)
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Early endoscopic treatment of blunt traumatic pancreatic injury
- 2015
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Ingår i: Scandinavian Journal of Gastroenterology. - : TAYLOR and FRANCIS LTD. - 0036-5521 .- 1502-7708. ; 50:12, s. 1435-1443
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Forskningsöversikt (refereegranskat)abstract
- Blunt pancreatic trauma is a rare and challenging situation. In many cases, there are other associated injuries that mandate urgent operative treatment. Morbidity and mortality rates are high and complications after acute pancreatic resections are common. The diagnosis of pancreatic injuries can be difficult and often requires multimodal approach including Computed Tomography scans, Magnetic resonance imaging and Endoscopic retrograde cholangiopancreaticography (ERCP). The objective of this paper is to review the application of endoprothesis in the settings of pancreatic injury. A review of the English literature available was conducted and the experience of our centre described. While the classical recommended treatment of Grade III pancreatic injury (transection of the gland and the pancreatic duct in the body/tail) is surgical resection this approach carries high morbidity. ERCP was first reported as a diagnostic tool in the settings of pancreatic injury but has in recent years been used increasingly as a treatment option with promising results. This article reviews the literature on ERCP as treatment option for pancreatic injury and adds further to the limited number of cases reported that have been treated early after the trauma.
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| 8. |
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| 9. |
- Forssberg, Eric, et al.
(författare)
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Utilization of the Reichert cone concentrator in ore processing
- 1979
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Ingår i: Industrie Minérale. Minéralurgie. - 0367-8962. ; :4, s. 223-232
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Tidskriftsartikel (refereegranskat)abstract
- This article describes the Reichert cone concentrator EM DASH a gravity separation device which operates on the principle of fluid bed separation on an inclined plane EM DASH and then discusses the present uses and potential applications of Reichert cones in ore beneficiation. Examples are given of the concentration of Liberian iron ore and the separation of fine coal on Reichert cones.
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| 10. |
- Gahan, Chandra Sekhar, et al.
(författare)
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A study on the toxic effects of chloride on the biooxidation efficiency of pyrite
- 2009
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Ingår i: Journal of Hazardous Materials. - : Elsevier BV. - 0304-3894 .- 1873-3336. ; 172:2-3, s. 1273-1281
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Tidskriftsartikel (refereegranskat)abstract
- Bioleaching operations in areas with limited chloride-free water and use of ashes and dust as neutralizing agents have motivated to study the chloride toxicity and tolerance level of the microorganisms. Biooxidation of pyrite using chloride containing waste ash compared with Ca(OH)2 + NaCl as neutralizing agent was investigated to evaluate the causes of low pyrite oxidation. Both precipitation of jarosite as well as the toxic effect of chloride on the microorganisms were responsible for lower pyrite recoveries. Another study with sudden exposure of chloride during pyrite biooxidation, addition of 4 g/L was lethal for the microorganisms. Addition of 2 g/L chloride resulted in precipitation of jarosite with slightly lower pyrite recovery whereas the addition of 3 g/L chloride temporarily chocked the microorganisms but activity was regained after a short period of adaptation. Population dynamics study conducted on the experiment with 3 g/L chloride surprisingly showed that Leptospirillum ferriphilum, which was dominating in the inoculum, completely disappeared from the culture already before chloride was added. Sulphobacillus sp. was responsible for iron oxidation in the experiment. Both Acidithiobacillus caldus and Sulphobacillus sp. were adaptive and robust in nature and their numbers were slightly affected after chloride addition. Therefore, it was concluded that the microbial species involved in the biooxidation of pyrite vary in population during the different stages of biooxidation.
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