Steel slag as a low-cost sorbent for metal removal in the presence of chelating agents

Eveliina Repo,Jolanta K. Warchoł,Lena Johansson Westholm,Mika Sillanpaa 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.27 No.-

Industrial byproduct, steel slag was used as a low-cost sorbent for the removal of Co(II), Ni(II), Cd(II), andPb(II) from aqueous solutions containing chelating agents; EDTA, citrate, and oxalate. Equilibrium andkinetic studies were conducted. Clear dependency between speciation of metals and their sorptionbehavior was observed. Precipitation and adsorption were suggested as main mechanisms. Diffusionplayed an important role in the kinetics of metal removal. Notable leaching of elements was observedwhen steel slag was in contact with the solutions under study. Modification with chitosan wassuccessfully used to prevent leaching and improve the sorption capacity of steel slag.

Outcomes following the operative treatment of intra-articular fracture combined with medial patellofemoral ligament reconstruction after patellar dislocation

( Jussi P. Repo ),( Mikko M. Uimonen ),( Mika T. Nevalainen ),( Heikki Nurmi ),( Ville T. Ponkilainen ),( Antti Tuominen ),( Juha Paloneva ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Purpose: We examine the outcomes following operative treatment of intra-articular fracture combined with medial patellofemoral ligament (MPFL) reconstruction after patella dislocation. Methods: Patients were retrospectively identified from medical records using diagnostic and surgical procedure codes. Radiological anatomical parameters and bony abnormalities of injured knees were assessed from magnetic resonance images (MRI). Inclusion criteria were traumatic patellar dislocation with chondral or osteochondral fracture and MPFL rupture, operative treatment of a chondral or osteochondral fracture combined with MPFL reconstruction, and minimum follow-up of 2 years. Outcomes were measured using the Kujala score, Tegner activity scale, and the Knee injury and Osteoarthritis Outcome Score Quality-of-Life subscale (KOOS-QLS). Results: During 2012 and 2015, 322 patients were treated because of patellar dislocation. Thirty-three patients had chondral or osteochondral fracture. Eleven patients (five males and six females) with a mean [standard deviation (SD)] age of 17.0 (6.5) years at the time of surgery met the inclusion criteria and were included. Five of the 11 patients had a subchondral and six an osteochondral fracture. Eight patients had a fracture in the patella and three in the femur. All patients had bony abnormalities in the knee. Nine out of 11 patients scored over 90/100 points on the Kujala scale and had good results on the Tegner scale [before surgery 5.0 (2.7) points versus after surgery 5.3 (1.6) points] and the KOOS-QLS [4.1 (4.2) points] outcome measures. Conclusion: The removal or fixation of the fracture fragment combined with MPFL reconstruction is a feasible option in the treatment of symptomatic osteochondral or subchondral fragment in traumatic patellar dislocation. The shortterm outcomes are encouraging. Level of evidence: Level IV, retrospective case series.

The effect of UV-C irradiation and EDTA on the uptake of Co2+ by antimony oxide in the presence and absence of competing cations Ca2+ and Ni2+

Leena Malinen,Eveliina Repo,Risto Harjula,Nina Huittinen 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.2

In nuclear power plants and other nuclear facilities the removal of cobalt from radioactive liquid waste isneeded to reduce the radioactivity concentration in effluents. In liquid wastes containing strong organiccomplexing agents such as EDTA cobalt removal can be problematic due to the high stability of the CoEDTA complex. In this study, the removal of cobalt from NaNO3 solutions using antimony oxide (Sb2O3)synthesized from potassium hexahydroxoantimonate was investigated in the absence and presence ofEDTA. The uptake studies on the ion exchange material were conducted both in the dark (absence of UVlight) and under UV-C irradiation. Ca2þ or Ni2þ were included in the experiments as competing cations totest the selectivity of the ion exchanger. Results show that UV-C irradiation noticeably enhances thecobalt sorption efficiency on the antimony oxide. It was shown that nickel decreased the sorption ofcobalt to a higher extent than calcium. Finally, the sorption data collected for Co2þ on antimony oxidewas modeled using six different isotherm models. The Sips model was found to be the most suitablemodel to describe the sorption process. The Dubinin-Radushkevich model was further used to calculatethe adsorption energy, which was found to be 6.2 kJ mol1

Validity and reliability of the motivation for physical activity (RM4-FM) questionnaire

Mikko Uimonen,Jussi P. Repo,Kiira Grönroos,Arja Häkkinen,Simon Walker 한국운동재활학회 2021 JER Vol.17 No.2

Influence of DFIG Reactive Current Injection during a Voltage Dip on the Operation of Wind Turbine Circuit Breaker

A. S. Makinen,O. Raipala,S. Repo,H. Tuusa 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5

This paper deals with an issue that has not received much attention in literature. The aim of the study is to investigate the influence of doubly fed induction generator (DFIG) reactive current injection during a voltage dip on the operation of a wind turbine circuit breaker. The study is done using a novel hardware-in-the-loop test environment constructed using two real time simulators (dSPACE and RTDS) and commercial protection relay. It is found in this study that the reactive current injection enhances the operation of wind turbine protection since the zero crossing of the circuit breaker currents is achieved earlier. This action may prevent from failed auto reclosing and other safety hazards.

CdS microspheres composed of nanocrystals and their photocatalytic activity.

Rengaraj, Selvaraj,Jee, Sun Hee,Venkataraj, Selvaraj,Kim, Younghun,Vijayalakshmi, Selvaraj,Repo, Eveliina,Koistinen, Arto,Sillanp??, Mika American Scientific Publishers 2011 Journal of nanoscience and nanotechnology Vol.11 No.3

<P>A simple and template-free solution phase synthesis method has been developed for the preparation of novel CdS hollow microspheres using cadmium nitrate and thioacetamide precursors. In this manuscript, we demonstrate that process parameters such as the reaction time, precursor ratio, and reaction temperature strongly influence the morphology of the final product. The synthesized products have been characterized by a variety of methods, including X-ray powder diffraction (XRD), Raman spectroscopy, high-resolution scanning electron microscopy (HR-SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray diffraction (EDX) analysis, X-ray photoelectron spectroscopy (XPS), and UV-visible diffused reflectance spectroscopy (UV-DRS). XRD analysis confirmed the cubic structure of the CdS microspheres, which has also been further supported by Raman spectroscopy. The HR-SEM measurements revealed the spherical morphology of the CdS microspheres which has been evolved by the oriented aggregation of the primary CdS nanocrystals. The TEM measurements confirmed the hollow shell-like structure of the spheres; the formation of their hollow interiors can be explained by the Ostwald ripening mechanism. UV-DRS studies showed that the band gap of the CdS microspheres increased with increasing cadmium-nitrate-to-thioacetamide ratio. Furthermore, studies of photocatalytic activity revealed that the synthesized CdS hollow microspheres exhibit an excellent photocatalytic performance in rapidly degrading methyl tert-butyl ether (MTBE) in aqueous solution under visible-light illumination. These results suggest that CdS microspheres will be an interesting candidate for photocatalytic detoxification studies under visible light radiation.</P>

Psychometric Properties of the Scoliosis Research Society Questionnaire (Version 22r) Domains Among Adults With Spinal Deformity: A Rasch Measurement Theory Analysis

Kati Kyrölä,Susanna Hiltunen,Mikko M. Uimonen,Jari Ylinen,Arja Häkkinen,Jussi P. Repo 대한척추신경외과학회 2022 Neurospine Vol.19 No.2

Objective: Adult spinal deformity (ASD) have lower health-related quality of life (HRQoL) compared to the general population. Applying Rasch measurement theory (RMT), this study tested the revised Scoliosis Research Society-22 (SRS-22r) HRQoL instrument among symptomatic adult patients with degenerative spinal disorders and varying degrees of ASD. Methods: SRS-22r data from 637 outpatient spine clinic patients with degenerative spine conditions were investigated for unidimensionality, item/scale fit, differential item functioning (DIF), scale coverage/targeting, and person separation index (PSI) using RMT. Results: Unidimensionality of the SRS-22r was not supported for either the total score or for 3 of its 5 domains. Item fit was acceptable for 11/22 items. The individual domains showed good coverage despite the degree of structural disorders. Ordered thresholds were achieved by merging response categories in some of the items. DIF towards age or sex was found in 11/22 items and in some domain items. The PSI exceeded 0.7 for the SRS-22r total score. Conclusion: The individual domain scores of the SRS-22r perform better than the total score providing good coverage and targeting among patients with ASD. Refinements of items and domains may improve the structural validity of the instrument to meet the criteria for measuring ASD patients, even when multidimensionality persists.

The influence of primary treatment approach on outcomes in patients with osteochondral fracture after patellar dislocation: a case series

( Mikko Uimonen ),( Ville Ponkilainen ),( Ville M. Mattila ),( Heikki Nurmi ),( Juha Paloneva ),( Jussi P. Repo ) 대한슬관절학회 2023 대한슬관절학회지 Vol.35 No.-

Background We characterized the relation of primary treatment approaches to the need of later surgical interventions and the outcomes of patellar dislocation in patients with patellofemoral osteochondral fracture (OCF). Methods Overall, 134 patients with OCF were categorized in two groups according to treatment approach: primary surgery (operation within 90 days from injury) and conservative treatment. Data on surgical procedures, OCF characteristics, and patellofemoral anatomy were retrospectively collected. To measure subjective outcomes, 54 patients completed the knee-specific patient-reported outcome measures (PROMs) Kujala score, Tegner activity scale, the knee injury and osteoarthritis outcome score (KOOS) quality of life (QoL) subscale, and visual analog scale pain items. Results The mean follow-up time was 4.9 years [standard deviation (SD) 2.7 years]. The primary treatment approach was surgery in 73 patients (54%) and conservative in 61 patients (46%) of whim 18 (30%) needed late surgery. Of primary surgery patients, the OCF was reimplanted in 45 patients (62%) and removed in the rest. Of all patients, 31 needed surgery in the later phase after the primary treatment approach (either reoperation or surgery after insufficient outcome of conservative treatment). In conservatively treated patients, OCF was smaller and patellofemoral joint malformation was more severe than in surgery group. Among patients who completed the PROMs, the outcomes appeared generally acceptable in both groups. Conclusions Although a majority of the primary treatment approaches for OCF after patellar dislocation were definitive, one-fourth of patients required surgery in the later phase. PROMs did not indicate major differences between the study groups.