Browsing by Subject "DEVICES"

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  • Barmaki, Samineh; Obermaier, Daniela; Kankuri, Esko; Vuola, Jyrki; Franssila, Sami; jokinen, Ville (2020)
    A hypoxic (low oxygen level) microenvironment and nitric oxide paracrine signaling play important roles in the control of both biological and pathological cell responses. In this study, we present a microfluidic chip architecture for nitric oxide delivery under a hypoxic microenvironment in human embryonic kidney cells (HEK-293). The chip utilizes two separate, but interdigitated microfluidic channels. The hypoxic microenvironment was created by sodium sulfite as the oxygen scavenger in one of the channels. The nitric oxide microenvironment was created by sodium nitroprusside as the light-activated nitric oxide donor in the other channel. The solutions are separated from the cell culture by a 30 µm thick gas-permeable, but liquid-impermeable polydimethylsiloxane membrane. We show that the architecture is preliminarily feasible to define the gaseous microenvironment of a cell culture in the 100 µm and 1 mm length scales.
  • Harju, Vilhelmiina; Koskinen, Antti; Pehkonen, Leila (2019)
    Background: The importance of digital technologies for enhancing learning in formal education settings has been widely acknowledged. In the light of this expectation, it is important to investigate the effects of these technologies on students' learning and development. Purpose: This study explores longitudinal empirical research on digital learning in the context of primary and secondary education. By focusing on a small selection of the peer-reviewed literature, the aim is to examine the kinds of longitudinal study published on this topic during the period 2012-2017 and, thorough categorisation, to bring together insights about the reported influences of digital technology use on students' learning. Design and methods: The databases searched for the purposes of this review were Scopus and Web of Science. Of 1,989 articles, 13 were finally included in the review. Using qualitative content analysis, these were analysed, coded and categorised. Results: The reviewed studies were found to have approached digital learning in different ways: they varied, for example, in terms of research methods and design and the digital technologies used. The studies addressed different aspects of learning, which we assigned to six categories: affection, attitude, and motivation; subject-specific knowledge and skills; transversal skills; learning experience; elements of the learning environment; and identity. We identified both positive and negative influences of technology on learning. Conclusions: This review offers a snapshot of the variety of research in this fast-moving area. The studies we explored were found to approach digital learning from several different perspectives, and no straightforward conclusions can be drawn about the influences of digital technology use on students' learning. We conclude that further longitudinal studies of digital learning are needed, and this study assists by highlighting gaps in the existing literature.
  • Vuorinen, Aino-Maija; Lehtonen, Jukka; Pakarinen, Sami; Holmström, Miia; Kivistö, Sari; Kaasalainen, Touko (2022)
    Background Some myocardial diseases, such as cardiac sarcoidosis, predispose to complete atrioventricular block. The European Society of Cardiology Guidelines on cardiac pacing in 2021 recommend myocardial disease screening in patients with conduction disorder requiring pacemaker with multimodality imaging, including cardiac magnetic resonance (CMR) imaging. The ability of CMR imaging to detect myocardial disease in patients with a temporary pacing wire is not well documented. Methods and Results Our myocardial disease screening protocol is based on using an active fixation pacing lead connected to a reusable extracorporeal pacing generator (temporary permanent pacemaker) as a bridge to a permanent pacemaker. From 2011 to 2019, we identified 17 patients from our CMR database who underwent CMR imaging with a temporary permanent pacemaker for atrioventricular block. We analyzed their clinical presentations, CMR data, and pacemaker therapy. All CMRs were performed without adverse events. Pacing leads induced minor artifacts to the septal myocardial segments. The extent of late gadolinium enhancement in CMR imaging was used to screen patients for the presence of myocardial disease. Patients with evidence of late gadolinium enhancement underwent endomyocardial biopsy. If considered clinically indicated, also 18-F-fluorodeoxyglucose positron emission tomography and extracardiac tissue biopsy were performed if sarcoidosis was suspected. Eventually, 8 of 17 patients (47.1%) were diagnosed with histologically confirmed granulomatous inflammatory cardiac disease. Importantly, only 1 had a previously diagnosed extracardiac sarcoidosis at the time of presentation with high-degree atrioventricular block. Conclusions CMR imaging with temporary permanent pacemaker protocol is an effective and safe early screening tool for myocardial disease in patients presenting with atrioventricular block requiring immediate, continuous pacing for bradycardia.
  • Nerenz, Robert D.; Yarbrough, Melanie L.; Stenman, Ulf-Hakan; Gronowski, Ann M. (2016)
    Objective: Elevated concentrations of hCG beta core fragment (hCG beta cf) are known to cause false-negative results in qualitative urine pregnancy test devices, but the pattern of urinary hCG beta cf during normal pregnancy has not been well characterized. Here, we evaluate the relationship between urine hCG, hCG beta cf, and hCG free beta subunit (hCG beta) during pregnancy. Design and methods: Banked second trimester urine specimens from 100 pregnant women were screened for high concentrations of hCG beta cf using a qualitative point-of-care device known to demonstrate false-negative results in the presence of elevated hCG beta cf concentrations. Additional first and third trimester specimens from the same pregnancy were obtained from 10 women who generated negative/faint positive results, 5 women who generated intermediate positive results, and 10 women who generated strong positive results on the point-of care device. Intact hCG, hCG beta cf, hCG beta, and specific gravity were quantified in these 75 specimens. Results: Urinary hCG beta cf concentrations were greater than intact hCG concentrations at all times. A strong correlation (r(2) = 0.70) was observed between urine intact hCG and hCG beta cf concentrations. A poor correlation was observed between specific gravity and intact hCG (r(2) = 0.32), hCG beta (r(2) = 0.32), and hCG beta cf (r(2) = 0.32). The highest hCG beta cf concentrations were observed between 10 and 16 weeks gestation but individual women demonstrated very different patterns of hCG beta cf excretion. Conclusions: Urine specimens with elevated hCG beta cf are frequently encountered during pregnancy but hCG beta cf excretion patterns are unpredictable. Manufacturers and clinicians must appreciate that hCG beta cf is the major immunoreactive component in urine during pregnancy and must design and interpret qualitative urine hCG test results accordingly. (C) 2016 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.
  • Harju, Jarkko; Vehkaoja, Antti; Lindroos, Ville; Kumpulainen, Pekka; Liuhanen, Sasu; Yli-Hankala, Arvi; Oksala, Niku (2017)
    Alterations in arterial blood oxygen saturation, heart rate (HR), and respiratory rate (RR) are strongly associated with intra-hospital cardiac arrests and resuscitations. A wireless, easy-to-use, and comfortable method for monitoring these important clinical signs would be highly useful. We investigated whether the Nellcor (TM) OxiMask MAX-FAST forehead sensor could provide data for vital sign measurements when located at the distal forearm instead of its intended location at the forehead to provide improved comfortability and easy placement. In a prospective setting, we recruited 30 patients undergoing surgery requiring postoperative care. At the postoperative care unit, patients were monitored for two hours using a standard patient monitor and with a study device equipped with a Nellcor (TM) Forehead SpO(2) sensor. The readings were electronically recorded and compared in post hoc analysis using Bland-Altman plots, Spearman's correlation, and root-mean-square error (RMSE). Bland-Altman plot showed that saturation (SpO(2)) differed by a mean of -0.2 % points (SD, 4.6), with a patient-weighted Spearman's correlation (r) of 0.142, and an RMSE of 4.2 points. For HR measurements, the mean difference was 0.6 bpm (SD, 2.5), r = 0.997, and RMSE = 1.8. For RR, the mean difference was -0.5 1/min (4.1), r = 0.586, and RMSE = 4.0. The SpO(2) readings showed a low mean difference, but also a low correlation and high RMSE, indicating that the Nellcor (TM) saturation sensor cannot reliably assess oxygen saturation at the forearm when compared to finger PPG measurements.
  • Sathyanarayanan, Gowtham; Haapala, Markus; Kiiski, Iiro; Sikanen, Tiina (2018)
    We report the development and characterization of digital microfluidic (DMF) immobilized enzyme reactors (IMERs) for studying cytochrome P450 (CYP)-mediated drug metabolism on droplet scale. The on-chip IMERs consist of porous polymer (thiol-ene) monolith plugs prepared in situ by photopolymerization and functionalized with recombinant CYP1A1 isoforms (an important detoxification route for many drugs and other xenobiotics). The DMF devices also incorporate inexpensive, inkjet-printed microheaters for on-demand regio-specific heating of the IMERs to physiological temperature, which is crucial for maintaining the activity of the temperature-sensitive CYP reaction. For on-chip monitoring of the CYP activity, the DMF devices were combined with a commercial well-plate reader, and a custom fluorescence quantification method was developed for detection of the chosen CYP1A1 model activity (ethoxyresorufin-O-deethylation). The reproducibility of the developed assay was examined with the help of ten parallel CYP-IMERs. All CYP-IMERs provided statistically significant difference (in fluorescence response) compared to any of the negative controls (including room-temperature reactions). The average (n = 10) turnover rate was 20.3 +/- 9.0 fmol resorufin per minute. Via parallelization, the concept of the droplet-based CYP-IMER developed in this study provides a viable approach to rapid and low-cost prediction of the metabolic clearance of new chemical entities in vitro.
  • Kettunen, Henrik; Lassas, Matti; Ola, Petri (2018)
    This paper considers transmission problems for the Helmholtz equation with bodies that have negative material parameters. Such material parameters are used to model metals on optical frequencies and so-called metamaterials. As the absorption of the materials in the model tends to zero, the fields may blow up. When the speed of the blow up is suitable, this is called the anomalous localized resonance (ALR). In this paper we study this phenomenon and formulate a new condition, the weak anomalous resonance (w-AR), where the speed of the blow up of fields may be slower. Using this concept, we can study the blow up of fields in the presence of negative material parameters without the commonly used quasi-static approximation. We give simple geometric conditions under which w-AR or ALR may or may not appear. In particular, we show that in a case of a curved layer of negative material with a strictly convex boundary, neither ALR nor w-AR appears with nonzero frequencies (i.e., in the dynamic range) in dimensions d >= 3. In the case when the boundary of the negative material contains a flat subset, we show that w-AR always happens with some point sources in dimensions d >= 2.
  • Malmberg, L. Pekka; Pelkonen, Anna S.; Vartiainen, Ville; Vahteristo, Mikko; Lähelmä, Satu; Jogi, Rain (2021)
    Background: To evaluate whether patients of varying ages and lung function with asthma or those with chronic obstructive pulmonary disease (COPD) can achieve sufficient inspiratory flows for effective use of the fixed-dose combination of salmeterol-fluticasone propionate and budesonide-formoterol dispensed with the Easyhaler (R) (EH) device-metered, multi-dose dry powder inhaler (DPI). Methods: A pooled analysis of two randomized, multicenter, crossover, open-label studies (NCT01424137; NCT009849061) was conducted to characterize inspiratory flow parameters across the EH, Seretide Diskus (DI) and Symbicort Turbuhaler (TH) inhalers in patients with asthma and/or COPD of varying severity. The primary endpoint was peak inspiratory flow (PIF) rate through the EH. Results: The intent-to-treat population comprised 397 patients; 383 patients were included in the per protocol (PP) population. The mean PIF (standard deviation) values through the EH in patients = 18 years of age with asthma and in those with COPD, were similar: 61.4 (11.5), 69.7 (13.5), and 61.9 (13.2) L/min, respectively. These flow rates correspond to pressure drops of 5.05 (1.80), 6.52 (2.34) and 5.19 (2.07) kPa, respectively. In total, 380 (99.2%) of patients in the PP population were able to generate a PIF rate through the EH of >= 30 L/min, which is required to enable consistent dose delivery from the DPI; there was a moderate direct association between age and PIF in younger patients with asthma, but this was inverse and less apparent in adult patients with asthma and/or those with COPD. Height and weight were also moderately correlated with PIF. Stronger associations with PIF were observed for some lung function parameters, particularly native PIF and forced inspiratory vital capacity. Conclusions: Over 99% of patients with asthma and/or COPD were able to inhale through the EH with an adequate PIF rate, irrespective of age, or severity of airway obstruction. This confirms that patients with asthma and/or COPD can achieve inspiratory flows via the EH DPI that are sufficient for its effective use.
  • Kolehmainen, Ville; Lassas, Matti; Ola, Petri; Siltanen, Samuli (2013)
  • Lavorini, Federico; Chudek, Jerzy; Gálffy, Gabriella; Pallarés-Sanmartin, Abel; Pelkonen, Anna S.; Rytilä, Paula; Syk, Jörgen; Szilasi, Maria; Tamási, Lilla; Xanthopoulos, Athanasios; Haahtela, Tari (2021)
    Asthma and chronic obstructive pulmonary disease (COPD) are major causes of morbidity and mortality worldwide. Optimal control of these conditions is a constant challenge for both physicians and patients. Poor inhaler practice is widespread and is a substantial contributing factor to the suboptimal clinical control of both conditions. The practicality, dependability, and acceptability of different inhalers influence the overall effectiveness and success of inhalation therapy. In this paper, experts from various European countries (Finland, Germany, Hungary, Italy, Poland, Spain, and Sweden) address inhaler selection with special focus on the Easyhaler® device, a high- or medium–high resistance dry-powder inhaler (DPI). The evidence examined indicates that use of the Easyhaler is associated with effective control of asthma or COPD, as shown by the generally accepted indicators of treatment success. Moreover, the Easyhaler is widely accepted by patients, is reported to be easy to learn and teach, and is associated with patient adherence. These advantages help patient education regarding correct inhaler use and the rational selection of drugs and devices. We conclude that switching inhaler device to the Easyhaler may improve asthma and COPD control without causing any additional risks. In an era of climate change, switching from pressurized metered-dose inhalers to DPIs is also a cost-effective way to reduce emissions of greenhouse gases. [MediaObject not available: see fulltext.].
  • Lassas, Matti; Liimatainen, Tony; Salo, Mikko (2020)
    We introduce a new approach to the anisotropic Calderón problem, based on a map called Poisson embedding that identifies the points of a Riemannian manifold with distributions on its boundary. We give a new uniqueness result for a large class of Calderón type inverse problems for quasilinear equations in the real analytic case. The approach also leads to a new proof of the result of Lassas et al. (Annales de l’ ENS 34(5):771–787, 2001) solving the Calderón problem on real analytic Riemannian manifolds. The proof uses the Poisson embedding to determine the harmonic functions in the manifold up to a harmonic morphism. The method also involves various Runge approximation results for linear elliptic equations.