Aurinkosähköjärjestelmän latauksen ohjaus säteilyennusteen perusteella

Tiivistelmä. Sähköverkon ulkopuolisia aurinkosähköjärjestelmiä voidaan käyttää pienen virrankulutuksen omaavien järjestelmien energialähteenä. Tämän tyyppisiä järjestelmiä ovat esimerkiksi maastoon sijoitetut IoT (Internet of Things) -sensorit. Näiden aurinkosähköjärjestelmien mitoitusta pohjoisilla leveysasteilla ympärivuotiseen käyttöön vaikeuttaa talvikuukausien aikana saatavilla olevan auringonsäteilyn vähäinen määrä ja sen vuosittainen vaihtelu. Tutkimuksen tavoitteena oli selvittää, voidaanko matalatehoisen aurinkosähköjärjestelmän tuottoa parantaa ohjaamalla lataussäätimen toimintaa säteilyennusteen avulla. Työssä toteutettiin laskentasovellus, jonka avulla mallinnettiin latauksen jaksotusta ja energiakertymää aurinkosähköjärjestelmälle, joka mitoitettiin tyypillistä kaupallista lähettävää riistakameraa varten. Mallinnusten pohjana käytettiin säteilyhavaintoaineistoa, joka oli kerätty Rovaniemen lentokentän sääasemalta vuosien 2010–2021 marras–tammikuussa. Työssä verrattiin toisiinsa kolmea eri ohjausmenetelmää laskemalla niiden kuukausikohtainen tuotto eri vuosien säteilyhavaintoaineistosta. Säteilyennusteeseen perustuvaa latauksen jaksottamista verrattiin auringon nousu- ja laskuaikojen perusteella jaksotettuun lataukseen. Kymmenen vuoden tarkastelujakson tuloksena säteilyennustukseen perustuva jaksotus tuotti keskimäärin marraskuussa 3,2 %, joulukuussa 35,3 % ja tammikuussa 6,9 % enemmän energiaa kuin auringon nousu- ja laskuaikojen perusteella jaksotettu lataus. Jatkuvasti päällä oleva lataus ei tuottanut energiaa joulukuussa tarkastelujakson aikana. Tämän työn perusteella pimeissä olosuhteissa lataussäätimen ohjausmenetelmänä on kannattavaa käyttää säteilyennusteeseen perustuvaa latauksen jaksottamista. Sen avulla saadaan kerättyä muita ohjausmenetelmiä enemmän energiaa ja se huomio vuosittaisen auringonsäteilyn määrän vaihtelun.Charging control of the photovoltaic system based on radiation forecast. Abstract. Off-grid photovoltaic systems are typically used as a power source for low-power systems, including off-road IoT (Internet of Things) sensors. The sizing of these photovoltaic systems in northern latitudes for year-round use is hampered by the small amount of solar radiation available during the winter months and its annual variability. The study aimed to determine whether the output of a low-power photovoltaic system can be improved by controlling the operation of the charge controller using radiation prediction. This thesis included implementing a computational application to model the charge cycle and energy accumulation for a photovoltaic system that was dimensioned for a typical commercial transmitting trail camera. The modelling was based on radiation observation data collected from the weather station at Rovaniemi Airport in November–January 2010–2021. The thesis compared three control methods by calculating their monthly return from radiation observation data from different years. The charging cycle based on radiation forecast was compared to that based on sunrise and sunset times. As a result of the ten-year review period, cycling based on radiation prediction produced an average of 3.2% more energy in November, 35.3% in December and 6.9% more in January than charging based on sunrise and sunset times. The continuous charging method did not generate energy in December during the review period. Based on this thesis, it is advantageous to use charge cycling based on radiation prediction as a control method for charge controller in dark conditions. It allows more energy to be collected than other control methods and considers the variation in the amount of solar radiation each year

Rakennusmateriaalien vaimennusmittaukset 28 GHz:n taajudella

Tiivistelmä. Tämä kandidaatintyö on toteutettu yhteistyössä Nokia Oyj:n kanssa. Tähän työhön liittyvät mittaukset suoritettiin joulukuu 2018 – helmikuu 2019 välisenä aikana Nokia Oyj:n OTAVA-laboratoriossa, joka sijaitsee Oulun Ruskossa. Mittauksissa käytettiin seinämateriaaleja, joista mallinnettiin hypoteettisia seiniä. Tässä työssä keskitytään 28 GHz:n signaalin läpäisyominaisuuksiin eri rakennusmateriaaleissa. Mittauksista saatujen tuloksien avulla saatiin määritettyä eri materiaaleille 1/cm vaimennus, jonka avulla mallinnettiin kahden erilaisen sisäseinän ja yhden ulkoseinän kokonaisvaimennusta. 1/cm vaimennukset vaihtelivat 0.3–22.7 dB välillä. Työssä perehdytään myös sähkömagneettisen säteilyn, polarisaation ja vapaan tilan vaimennuksen teoriaan sekä antennin ominaisuuksiin. Lopuksi käsitellään yksittäisten mittausten pohjalta tehtyjä varmistusmittauksia sekä esitellään jatkotutkimusmahdollisuuksia.Attenuation measurements of construction materials at 28 GHz frequency. Abstract. This Bachelor’s Thesis is made in co-operation with Nokia. The measurements that were included in the thesis took place between December 2018 and February 2019 in Nokia’s OTAVA-laboratory, which is located in Rusko, Oulu, Finland. With the measurements it was possible to model hypothetical completed walls. This thesis focuses on the penetrating loss of the different kinds of wall materials at 28 GHz frequency. With the measurement results, the 1/cm attenuation were defined to different kinds of materials. With the attenuations it was possible to model the total attenuation of two different inner walls and one external wall. The 1/cm attenuation values varied between 0.3 and 22.7 dB. In this thesis, the electromagnetic radiation, polarisation, free space path loss, as well as the antenna properties will be introduced. In the end of this thesis, the verification measurements that were done based on the separate measurements, will be discussed and the possibilities of the further studies will be discussed

Direct puncture of the carotid artery as a bailout vascular access technique for mechanical thrombectomy in acute ischemic stroke—the revival of an old technique in a modern setting

Purpose: To describe our single-center experience of mechanical thrombectomy (MTE) via a direct carotid puncture (DCP) with regard to indication, time metrics, procedural details, as well as safety and efficacy aspects. Methods: DCP thrombectomy cases performed at our center were retrospectively identified from a prospectively maintained institutional MTE database. Various patient (age, sex, stroke cause, comorbidities), clinical (NIHSS, mRS), imaging (occlusion site, ASPECT score), procedural (indication for DCP, time from DCP to reperfusion, materials used, technical nuances), and outcome data (NIHSS, mRS) were tabulated. Results: Among 715 anterior circulation MTEs, 12 DCP-MTEs were identified and analyzed. Nine were left-sided M1 occlusions, one right-sided M1 occlusion, and two right-sided M2 occlusions. DCP was successfully carried out in 91.7%; TICI 2b/3-recanalization was achieved in 83.3% via direct lesional aspiration and/or stent-retrieval techniques. Median time from DCP to reperfusion was 23 min. Indications included futile transfemoral catheterization attempts of the cervical target vessels as well as iliac occlusive disease. Neck hematoma occurred in 2 patients, none of which required further therapy. Conclusion: MTE via DCP in these highly selected patients was reasonably safe, fast, and efficient. It thus represents a valuable technical extension of MTE, especially in patients with difficult access

Delirium in older hospitalized patients—A prospective analysis of the detailed course of delirium in geriatric inpatients

Background: Delirium in older hospitalized patients (> 65) is a common clinical syndrome, which is frequently unrecognized. Aims: We aimed to describe the detailed clinical course of delirium and related cognitive functioning in geriatric patients in a mainly non-postoperative setting in association with demographic and clinical parameters and additionally to identify risk factors for delirium in this common setting. Methods: Inpatients of a geriatric ward were screened for delirium and in the case of presence of delirium included into the study. Patients received three assessments including Mini-Mental-Status-Examination (MMSE) and the Delirium Rating Scale Revised 98 (DRS-R-98). We conducted correlation and linear mixed-effects model analyses to detect associations. Results: Overall 31 patients (82 years (mean)) met the criteria for delirium and were included in the prospective observational study. Within one week of treatment, mean delirium symptom severity fell below the predefined cut-off. While overall cognitive functioning improved over time, short- and long-term memory deficits remained. Neuroradiological conspicuities were associated with cognitive deficits, but not with delirium severity. Discussion: The temporal stability of some delirium symptoms (short-/long-term memory, language) on the one hand and on the other hand decrease in others (hallucinations, orientation) shown in our study visualizes the heterogeneity of symptoms attributed to delirium and their different courses, which complicates the differentiation between delirium and a preexisting cognitive decline. The recovery from delirium seems to be independent of preclinical cognitive status. Conclusion: Treatment of the acute medical condition is associated with a fast decrease in delirium severity. Given the high incidence and prevalence of delirium in hospitalized older patients and its detrimental impact on cognition, abilities and personal independence further research needs to be done

Isolated Striatocapsular Infarcts after Endovascular Treatment of Acute Proximal middle Cerebral Artery Occulusion: Prevalence, Enabling Factors, and Clinical Outcomes

Background: Striatocapsular infarcts (SCIs) are defined as large subcortical infarcts involving the territory of more than one lenticulostriate artery. SCI without concomitant ischemia in the more distal middle cerebral artery (MCA) territory [isolated SCI (iSCI)] has been described as a rare infarct pattern. The purpose of this study was to assess the prevalence of iSCI in patients treated with endovascular thrombectomy (ET), to evaluate baseline and procedural parameters associated with this condition, and to describe the clinical course of iSCI patients. Methods: A retrospective analysis of 206 consecutive patients with an isolated MCA occlusion involving the lenticulostriate arteries and treated with ET was performed. Baseline patient and procedural characteristics and ischemic involvement of the striatocapsular and distal MCA territory [iSCI, as opposed to non-isolated SCI (niSCI)] were analyzed using multivariate logistic regression models. Prevalence of iSCI was assessed, and clinical course was determined with the rates of substantial neurological improvement and good functional short-and mid-term outcome (discharge/day 90 Modified Rankin Scale <= 2). Results: iSCI was detected in 53 patients (25.7%), and niSCI was detected in 153 patients (74.3%). Successful reperfusion [thrombolysis in cerebral infarction (TICI) 2b/3] [adjusted odds ration (aOR) 8.730, 95% confidence interval (95% CI) 1.069-71.308] and good collaterals (aOR 2.100, 95% CI 1.119-3.944) were associated with iSCI. In successfully reperfused patients, TICI 3 was found to be an additional factor associated with iSCI (aOR 5.282, 1.759-15.859). Patients with iSCI had higher rates of substantial neurological improvement (71.7 vs. 37.9%, p < 0.001) and higher rates of good functional short-and mid-term outcome (58.3 vs. 23.7%, p < 0.001 and 71.4 vs. 41.7%, p < 0.001). However, while iSCI patients, in general, had a more favorable outcome, considerable heterogeneity in outcome was observed. Conclusion: High rates of successful reperfusion (TICl 2b/3) and in particular, complete reperfusion (TICl 3) are associated with iSCls. The high prevalence iSCl in successfully reperfused patients with good collaterals corroborates previous concepts of iSCl partho-genesis. iSCl, once considered a rare pattern of cerebral ischemia, is likely to become more prevalent with increase in endovascular stroke therapy. This may have implications for patient rehabilitation and pathophysiological analysis of ischemic damage confind to subcortical regions of the MCA territory

Volumetric accuracy of different imaging modalities in acute intracerebral hemorrhage

Background: Follow-up imaging in intracerebral hemorrhage is not standardized and radiologists rely on different imaging modalities to determine hematoma growth. This study assesses the volumetric accuracy of different imaging modalities (MRI, CT angiography, postcontrast CT) to measure hematoma size. Methods: 28 patients with acute spontaneous intracerebral hemorrhage referred to a tertiary stroke center were retrospectively included between 2018 and 2019. Inclusion criteria were (1) spontaneous intracerebral hemorrhage (supra- or infratentorial), (2) noncontrast CT imaging performed on admission, (3) follow-up imaging (CT angiography, postcontrast CT, MRI), and (4) absence of hematoma expansion confirmed by a third cranial image within 6 days. Two independent raters manually measured hematoma volume by drawing a region of interest on axial slices of admission noncontrast CT scans as well as on follow-up imaging (CT angiography, postcontrast CT, MRI) using a semi-automated segmentation tool (Visage image viewer; version 7.1.10). Results were compared using Bland-Altman plots. Results: Mean admission hematoma volume was 18.79 +/- 19.86 cc. All interrater and intrarater intraclass correlation coefficients were excellent (1; IQR 0.98-1.00). In comparison to hematoma volume on admission noncontrast CT volumetric measurements were most accurate in patients who received postcontrast CT (bias of - 2.47%, SD 4.67: n = 10), while CT angiography often underestimated hemorrhage volumes (bias of 31.91%, SD 45.54; n = 20). In MRI sequences intracerebral hemorrhage volumes were overestimated in T2* (bias of - 64.37%, SD 21.65; n = 10). FLAIR (bias of 6.05%, SD 35.45; n = 13) and DWI (bias of-14.6%, SD 31.93; n = 12) over- and underestimated hemorrhagic volumes. Conclusions: Volumetric measurements were most accurate in postcontrast CT while CT angiography and MRI sequences often substantially over- or underestimated hemorrhage volumes

Prevalence, Enabling Factors, and Clinical Outcome

Background: Striatocapsular infarcts (SCIs) are defined as large subcortical infarcts involving the territory of more than one lenticulostriate artery. SCI without concomitant ischemia in the more distal middle cerebral artery (MCA) territory [isolated SCI (iSCI)] has been described as a rare infarct pattern. The purpose of this study was to assess the prevalence of iSCI in patients treated with endovascular thrombectomy (ET), to evaluate baseline and procedural parameters associated with this condition, and to describe the clinical course of iSCI patients. Methods: A retrospective analysis of 206 consecutive patients with an isolated MCA occlusion involving the lenticulostriate arteries and treated with ET was performed. Baseline patient and procedural characteristics and ischemic involvement of the striatocapsular and distal MCA territory [iSCI, as opposed to non-isolated SCI (niSCI)] were analyzed using multivariate logistic regression models. Prevalence of iSCI was assessed, and clinical course was determined with the rates of substantial neurological improvement and good functional short- and mid-term outcome (discharge/day 90 Modified Rankin Scale ≤2). Results: iSCI was detected in 53 patients (25.7%), and niSCI was detected in 153 patients (74.3%). Successful reperfusion [thrombolysis in cerebral infarction (TICI) 2b/3] [adjusted odds ration (aOR) 8.730, 95% confidence interval (95% CI) 1.069–71.308] and good collaterals (aOR 2.100, 95% CI 1.119–3.944) were associated with iSCI. In successfully reperfused patients, TICI 3 was found to be an additional factor associated with iSCI (aOR 5.282, 1.759–15.859). Patients with iSCI had higher rates of substantial neurological improvement (71.7 vs. 37.9%, p < 0.001) and higher rates of good functional short- and mid-term outcome (58.3 vs. 23.7%, p < 0.001 and 71.4 vs. 41.7%, p < 0.001). However, while iSCI patients, in general, had a more favorable outcome, considerable heterogeneity in outcome was observed. Conclusion: High rates of successful reperfusion (TICI 2b/3) and in particular, complete reperfusion (TICI 3) are associated with iSCIs. The high prevalence of iSCI in successfully reperfused patients with good collaterals corroborates previous concepts of iSCI pathogenesis. iSCI, once considered a rare pattern of cerebral ischemia, is likely to become more prevalent with increases in endovascular stroke therapy. This may have implications for patient rehabilitation and pathophysiological analyses of ischemic damage confined to subcortical regions of the MCA territory

Discrepancy between early neurological course and mid-term outcome in older stroke patients after mechanical thrombectomy

Background Stroke in aged patients has a relatively poor prognosis, even after recanalizing therapy. Potential reasons include mechanisms that relate directly to the extent of brain tissue damage, but also age-dependent factors which are not, or only indirectly, stroke-related, such as pre-existing functional deficits, comorbidities, and post-stroke complications (eg, infections). Objective To compare early neurological course with subsequent functional outcome in older (>= 80 years) and younger stroke patients in order to estimate the relative impact of these factors. Specifically, to examine if the strong age-dependency of modified Rankin Scale (mRS) outcome scores in stroke patients after mechanical thrombectomy is paralleled by a similar age dependency of early postinterventional National Institute of Health Stroke Scale (NIHSS) scores-a more specific measure of stroke-induced brain damage. Methods We evaluated technical results, pre-and postinterventional NIHSS scores, mid-term mRS scores and early and overall mortality and their relation to age in 125 patients, 40 of them >= 80 years, with acute middle cerebral artery occlusion, treated by mechanical thrombectomy. Results Technical success, pre-and postinterventional NIHSS scores and early mortality were age-independent. Early neurological improvement depended on successful recanalization, but not on age. Nevertheless, good mRS outcome (mRS 0-2) was much rarer, and overall mortality almost threefold higher in aged patients. Conclusions Older patients exhibit a similar early neurological course and responsiveness to mechanical thrombectomy as younger patients, but this is not reflected in mid-term functional outcome scores. This indicates that post-stroke complications and other factors that are not, or only indirectly, related to the brain tissue damage induced by the incident stroke have a dominant role in their poor prognosis

Early Thrombectomy Protects the Internal Capsule in Patients With Proximal Middle Cerebral Artery Occlusion.

BACKGROUND AND PURPOSE Proximal middle cerebral artery (MCA) occlusions impede blood flow to the noncollateralized lenticulostriate artery territory. Previous work has shown that this almost inevitably leads to infarction of the dependent gray matter territories in the striate even if perfusion is restored by mechanical thrombectomy. Purpose of this analysis was to evaluate potential sparing of neighboring fiber tracts, ie, the internal capsule. METHODS An observational single-center study of patients with proximal MCA occlusions treated with mechanical thrombectomy and receiving postinterventional high-resolution diffusion-weighted imaging was conducted. Patients were classified according to internal capsule ischemia (IC+ versus IC-) at the postero-superior level of the MCA lenticulostriate artery territory (corticospinal tract correlate). Associations of IC+ versus IC- with baseline variables as well as its clinical impact were evaluated using multivariable logistic or linear regression analyses adjusting for potential confounders. RESULTS Of 92 included patients with proximal MCA territory infarctions, 45 (48.9%) had an IC+ pattern. Longer time from symptom-onset to groin-puncture (adjusted odds ratio, 2.12 [95% CI, 1.19-3.76] per hour), female sex and more severe strokes were associated with IC+. Patients with IC+ had lower rates of substantial neurological improvement and functional independence (adjusted odds ratio, 0.26 [95% CI, 0.09-0.81] and adjusted odds ratio, 0.25 [95% CI, 0.07-0.86]) after adjustment for confounders. These associations remained unchanged when confining analyses to patients without ischemia in the corona radiata or the motor cortex and here, IC+ was associated with higher National Institutes of Health Stroke Scale motor item scores (β, +2.8 [95% CI, 1.5 to 4.1]) without a significant increase in nonmotor items (β, +0.8 [95% CI, -0.2 to 1.9). CONCLUSIONS Rapid mechanical thrombectomy with successful reperfusion of the lenticulostriate arteries often protects the internal capsule from subsequent ischemia despite early basal ganglia damage. Salvage of this eloquent white matter tract within the MCA lenticulostriate artery territory seems strongly time-dependent, which has clinical and pathophysiological implications

The CD31 molecule: a possible neuroprotective agent in acute ischemic stroke?

Abstract Background The transmembrane receptor molecule CD31 is known to have immunomodulatory functions, suggesting a possible neuroprotective effect in the context of acute ischemic stroke by restricting an over-activation of secondary immunological processes. This study examines the density of CD31+ cells in mechanically extracted thrombi of stroke patients with the aim to test whether the occurrence of CD31+ cells was associated with a beneficial clinical outcome in those patients. Methods Thrombi of 122 consecutive patients with large anterior circulation stroke were collected during intracranial mechanical recanalization. Out of these, 86 immunostained specimens of adequate quality could be analysed. The density of CD31+ cells was quantified and compared with clinical outcome data of the affected patients. Results The density of CD31+ cells was positively related to early patient improvement (ΔNIHSS, r = 0.283, p = 0,012) with an even clearer relationship after exclusion of patients who died in the early hospital phase (r = 0.371, p = 0.001). This finding stayed stable also in the multivariate analysis after corrrection for other outcome-influencing factors (p = 0.049). Conclusion This study shows a stable relation between CD31+ cells and early clinical improvement of patients with acute ischemic stroke. This finding is in line with recent reports showing immunomodulatory and potential neuroprotective effects of CD31, suggesting that CD31 may be a promising neuroprotective agent in stroke patients