Hihnan päällä toimivan optisen 3D-granulometriajärjestelmän mekaanisten oheislaitteiden kehitys

This thesis presents the process of designing the mechanical structure for a commercial particle size analyzer of granular material based on on-line 3D optical granulometry technology. The analyzer can be used to monitor and increase the performance of various processes within the mining, mineral, and metal industry (MMMI), particularly grinding processes that utilize autogenous and semi-autogenous grinding mills. The analysis system contributes to the evolution of the MMMI in a more energy efficient direction, resulting in a decreased ecological footprint of the industry as well as financial benefits for the operators. The design work done for this thesis contributes to a product development project by Outotec, a technology company specializing in the MMMI. Prior work within the project included a detailed business analysis and software development. A systematic methodology to carry out the design work was derived from the field of engineering design literature. The methodology is based on decomposition of the design problem into smaller subproblems. By finding solutions for each subproblem individually, an overall conceptual solution is produced. This methodology was used to create explicit engineering parameters and a conceptual solution for the mechanical structure of the product, based on the prior work done on the product development project. The conceptual solution was then defined further into a complete mechanical design and a functional prototype. The prototype was tested and evaluated based on the engineering parameters. Based on the results, a second iteration of the design was created, improving on the initial design. Based on objective evaluation of the second design iteration, the design meets all the criteria set for the product development project and can be taken to market. However, the evaluation and further iteration of the design will continue after product launch based on customer feedback and product performance.Tämä diplomityö esittelee optiseen 3D granulometriateknologiaan perustuvan kaupallisen partikkelikokoanalysaattorin mekaanisen suunnitteluprosessin. Analysaattorin pääasiallinen käyttötarkoitus liittyy kaivosteollisuuden erinäisten prosessien monitorointiin ja ohjaukseen. Ensisijainen käyttökohde on autogeenisiä ja semiautogeenisiä myllyjä hyödyntävien jauhatusprosessien syöttömateriaalin monitorointi. Suunniteltu laitteisto edistää kaivosteollisuuden kehittymistä energiatehokkaampaan suuntaan ja siten toimialan aiheuttaman ekologisen jalanjäljen pienentämistä. Laitteen tarkoitus on myös tuottaa taloudellista hyötyä sekä kaivosteollisuuden operaattoreille että laitteen toimittajalle. Tämän diplomityö on tehty kaivosalalla toimivan teknologiayhtiön, Outotecin, toimeksiannosta ja edesauttaa erästä yhtiön tuotekehitysprojektia. Suunnittelutyö toteutettiin tuotekehitykseen liittyvästä kirjallisuudesta löydettyjä systemaattisia menetelmiä hyödyntäen. Käytetty suunnittelumetodiikka perustuu suunnitteluongelman jakamiseen pienempiin osatekijöihin. Suunnitteluongelma ratkaistaan löytämällä kullekin osatekijälle toimiva ratkaisu. Kyseiseen metodiikkaan sekä tuotekehitysprojektin aiempiin työpanoksiin perustuen tuotteelle luotiin yksikäsitteiset suunnitteluparametrit sekä mekaaninen konsepti. Konseptin pohjalta suunniteltiin tuotteen mekaaninen rakenne ja rakennettiin toimiva prototyyppi, joka testattiin aiemmin luotujen suunnitteluparametrien perusteella. Tulosten perusteella tuotteesta suunniteltiin toinen versio, jossa korjattiin testauksessa havaittuja puutteita. Toisen tuoteversion objektiivisen arvioinnin perusteella suunnittelutyön tavoitteisiin on päästy. Tämän arvion perusteella tuote täyttää kaikki sille asetetut kriteerit ja se voidaan viedä markkinoille. Tuotteen suorituskyvyn arviointi ja rakenteen iterointi jatkuu kuitenkin vielä markkinoille viennin jälkeen

Tietolaatikko kandille: neurokirurgia

Teema : aivokasvaimet. Kandin tietolaatikk

Rat subthalamic stimulation : Evaluating stimulation-induced dyskinesias, choosing stimulation currents and evaluating the anti-akinetic effect in the cylinder test

In experimental deep brain stimulation of the subthalamic nucleus (STN HFS), stimulation currents just below the appearance threshold of stimulation-induced dyskinesias has often been used. The behavioral effect of STN HFS can be measured by the reversal of forelimb use asymmetry produced by hemiparkinsonism can be measured with the cylinder test among other tests. We used 18 Wistar rats with 6-hydroxydopamine induced hemiparkinsonism to test a customized scale to rate the severity of stimulation-induced dyskinesia; we then used these ratings to choose low and high stimulation currents. Subsequent cylinder tests showed that stimulation at the higher current, inducing mild and short-lived dyskinesias, was required for robust improvement in forelimb use, contradicting the use of currents below stimulation-induced dyskinesia threshold. It was also beneficial to separately count both all touches and first touches with the cylinder wall; this provided additional sensitivity and robustness to our results. Scoring stimulation-induced dyskinesias can be used as a quantitative measure of dyskinesias and to choose stimulation currents. Cylinder test scoring separately for both first and all touches can improve both sensitivity and reliability. STN HFS at a current producing short-lived dyskinesias was required for robust improvement in forelimb use asymmetry. (C) 2019 The Authors. Published by Elsevier B.V.Peer reviewe

Spontaneous angiogram-negative subarachnoid hemorrhage : a retrospective single center cohort study

Background Spontaneous angiogram-negative subarachnoid hemorrhage (SAH) is considered a benign illness with little of the aneurysmal SAH-related complications. We describe the clinical course, SAH-related complications, and outcome of patients with angiogram-negative SAH. Methods We retrospectively reviewed all adult patients admitted to a neurosurgical intensive care unit during 2004-2018 due to spontaneous angiogram-negative SAH. Our primary outcome was a dichotomized Glasgow Outcome Scale (GOS) at 3 months. We assessed factors that associated with outcome using multivariable logistic regression analysis. Results Of the 108 patients included, 84% had a favorable outcome (GOS 4-5), and mortality was 5% within 1 year. The median age was 58 years, 51% were female, and 93% had a low-grade SAH (World Federation of Neurosurgical Societies grading I-III). The median number of angiograms performed per patient was two. Thirty percent of patients showed radiological signs of acute hydrocephalus, 28% were acutely treated with an external ventricular drain, 13% received active vasospasm treatment and 17% received a permanent shunt. In the multivariable logistic regression model, only acute hydrocephalus associated with unfavorable outcome (odds ratio = 4.05, 95% confidence interval = 1.05-15.73). Two patients had a new bleeding episode. Conclusion SAH-related complications such as hydrocephalus and vasospasm are common after angiogram-negative SAH. Still, most patients had a favorable outcome. Only acute hydrocephalus was associated with unfavorable outcome. The high rate of SAH-related complications highlights the need for neurosurgical care in these patients.Peer reviewe

Spontaneous angiogram-negative subarachnoid hemorrhage : a retrospective single center cohort study

Background Spontaneous angiogram-negative subarachnoid hemorrhage (SAH) is considered a benign illness with little of the aneurysmal SAH-related complications. We describe the clinical course, SAH-related complications, and outcome of patients with angiogram-negative SAH. Methods We retrospectively reviewed all adult patients admitted to a neurosurgical intensive care unit during 2004-2018 due to spontaneous angiogram-negative SAH. Our primary outcome was a dichotomized Glasgow Outcome Scale (GOS) at 3 months. We assessed factors that associated with outcome using multivariable logistic regression analysis. Results Of the 108 patients included, 84% had a favorable outcome (GOS 4-5), and mortality was 5% within 1 year. The median age was 58 years, 51% were female, and 93% had a low-grade SAH (World Federation of Neurosurgical Societies grading I-III). The median number of angiograms performed per patient was two. Thirty percent of patients showed radiological signs of acute hydrocephalus, 28% were acutely treated with an external ventricular drain, 13% received active vasospasm treatment and 17% received a permanent shunt. In the multivariable logistic regression model, only acute hydrocephalus associated with unfavorable outcome (odds ratio = 4.05, 95% confidence interval = 1.05-15.73). Two patients had a new bleeding episode. Conclusion SAH-related complications such as hydrocephalus and vasospasm are common after angiogram-negative SAH. Still, most patients had a favorable outcome. Only acute hydrocephalus was associated with unfavorable outcome. The high rate of SAH-related complications highlights the need for neurosurgical care in these patients.Peer reviewe

COVID-19-infektion neurologiset ilmentymät

Vertaisarvioitu.COVID-19-infektion neurologisista ilmentymistä kertynyt tieto on tapausselostusten ja -sarjojen hallitsemaa. Yleisimmät neurologiset ilmentymät ovat olleet haju- ja makuaistin muutokset. Aivoverenkiertohäiriöt, enkefalopatia ja immuunivälitteiset keskushermoston sairaudet tulevat usein esiin COVID-19-infektion komplikaatioina, mutta toisaalta Guillain-Barrén oireyhtymän osalta yhteys tähän infektioon kumottiin laajemmassa epidemiologisessa kohorttitutkimuksessa. Myös enkefaliitin, epileptisten kohtauksien, ääreishermoston sairauksien ja lihassairauksien on kuvattu liittyvän tähän infektioon. Neuropatologisissa tutkimuksissa tärkeimmät löydökset ovat olleet hypoksis-iskeeminen vaurio, verenvuodot ja epäspesifiset tulehdusmuutokset. Vielä odotellaan varmuutta siitä, aiheutuvatko kudosmuutokset viruksen invaasiosta aivoihin vai onko kyse epäsuorista muutoksista. Mekanismi SARS-CoV2-viruksen pääsylle aivokudokseen näyttäisi olevan olemassa. COVID-19-infektion jälkeisestä pitkittyneestä neurologisesta oireilusta tarvitaan lisää tutkimustietoa.Peer reviewe

Aivojen valtimo-laskimoepämuodostumat

English summar

Timing of surgery for ruptured supratentorial arteriovenous malformations

There are conflicting opinions regarding the optimal waiting time to perform surgery after rupture of supratentorial arteriovenous malformations (AVMs) to achieve the best possible outcome. To analyze factors influencing outcomes for ruptured supratentorial AVMs after surgery, paying particular attention to the timing of the surgery. We retrospectively investigated 59 patients admitted to our center between 2000 and 2014 for surgical treatment of ruptured supratentorial AVMs. We evaluated the effect of timing of surgery and other variables on the outcome at 2-4 months (early outcome), at 12 months (intermediate outcome) after surgery, and at final follow-up at the end of 2016 (late outcome). Age over 40 years (OR 18.4; 95% CI 1.9-172.1; p = 0.011), high Hunt and Hess grade (4 or 5) before surgery (OR 13.5; 95% CI 2.1-89.2; p = 0.007), hydrocephalus on admission (OR 12.9; 95% CI 1.8-94.4; p = 0.011), and over 400 cm(3) bleeding during surgery (OR 11.5; 95% CI 1.5-86.6; p = 0.017) were associated with an unfavorable early outcome. Age over 40 years (OR 62.8; 95% CI 2.6-1524.9; p = 0.011), associated aneurysms (OR 34.7; 95% CI 1.4-829.9; p = 0.029), high Hunt and Hess grade before surgery (OR 29.2; 95% CI 2.6-332.6; p = 0.007), and over 400 cm(3) bleeding during surgery (OR 35.3; 95% CI 1.7-748.7; p = 0.022) were associated with an unfavorable intermediate outcome. Associated aneurysms (OR 8.2; 95% CI 1.2-55.7; p = 0.031), high Hunt and Hess grade before surgery (OR 5.7; 95% CI 1.3-24.3; p = 0.019), and over 400 cm(3) bleeding during surgery (OR 5.8; 95% CI 1.2-27.3; p = 0.027) were associated with an unfavorable outcome at last follow-up. Elapsed time between rupture and surgery did not affect early or final outcome. Early surgery in patients with ruptured supratentorial arteriovenous malformation is feasible strategy, with late results comparable to those achieved with delayed surgery. Many other factors than timing of surgery play significant roles in long-term outcomes for surgically treated ruptured supratentorial AVMs.Peer reviewe

Arteriovenous Malformations of the Posterior Fossa : Focus on Surgically Treated Patients Presenting with Hemorrhage

BACKGROUND: Arteriovenous malformations (AVMs) of the posterior fossa are demanding lesions that often present with rupture. Studies including outcome analyses in surgically operated patients with ruptured infratentorial AVMs are scarce. Certain anatomic and demographic features have shown associations with postoperative outcomes. METHODS: Eighty-six patients with infratentorial AVM were collected from our AVM database. Fifty-four patients were admitted from 1990 onward, and their demographic, lesion, and treatment characteristics were analyzed. The cohort was further refined to 38 consecutive patients with surgically treated ruptured infratentorial AVM admitted to our center between 1990 and 2014, and statistical analyses of factors influencing outcomes were conducted. RESULTS: Twenty-seven patients (69%) had a favorable outcome at early follow-up and 24 (67%) had a favorable outcome at final follow-up. Factors associated with poor outcome in early recovery on univariate analyses were deep venous drainage of the lesion (odds ratio (OR 5.3; P = 0.037) and high Hunt & Hess score (P = 0.003). In the multivariate model, independent predictors for poor outcome were deep venous drainage (OR, 14.5; P = 0.010) and older age at admission (OR, 1.06; P = 0.028). The sole independent predictor for poor outcome at last follow-up was deep venous drainage (OR, 5.00; P = 0.046). The total follow-up time was 370 person-years. CONCLUSIONS: AVMs of the posterior fossa usually present with rupture and thus require prompt clinical treatment. The majority of surgically treated patients recover favorably. Our data show that venous drainage patterns have the greatest influence on the patient's postoperative condition. Other influencing factors include the severity of hemorrhage and patient age at admission.Peer reviewe