Hochschule für Technik und Umwelt FHNW

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Air cleaners and respiratory infections in schools. A modeling study using epidemiological, environmental, and molecular data
(Oxford University Press, 30.12.2023) Banholzer, Nicolas; Jent, Philipp; Bittel, Pascal; Zürcher, Kathrin; Furrer, Lavinia; Bertschinger, Simon; Weingartner, Ernest; Ramette, Alban; Egger, Matthias; Hascher, Tina; Fenner, Lukas
AbstractBackgroundUsing a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA-air filtration devices (air cleaners) in a school setting.MethodsWe collected environmental (CO2, particle concentrations), epidemiological (absences related to respiratory infections), audio (coughing), and molecular data (bioaerosol and saliva samples) over seven weeks during winter 2022/2023 in two Swiss secondary school classes. Using a cross-over study design, we compared particle concentrations, coughing, and the risk of infection with vs without air cleaners.ResultsAll 38 students (age 13−15 years) participated. With air cleaners, mean particle con-centration decreased by 77% (95% credible interval 63%−86%). There were no differences in CO2levels. Absences related to respiratory infections were 22 without vs 13 with air cleaners. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval 0.44−1.18). Coughing also tended to be less frequent (posterior probability 93%). Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive), but not in bioaerosols (2/105 positive) or HEPA-filters (4/160). The detection rate was similar with vs without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions.ConclusionsAir cleaners improved air quality, showed a potential benefit in reducing respiratory infections, and were associated with less coughing. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission, and the cost-effectiveness of using air cleaners.
01A - Beitrag in wissenschaftlicher Zeitschrift
Binocular advantages in reading revisited. Attenuating effects of individual horizontal heterophoria
(Bern Open Publishing, 09.12.2019) Jainta, Stephanie; Joss, Joëlle
Reading with two eyes necessitates efficient processes of binocular vision, which provide a single percept of the text. These processes come with a binocular advantage: binocular reading shows shorter average fixation durations and sentence reading times when compared to monocular reading. A couple of years ago, we showed for a small sample (N=13) that binocular advantages critically relate to the individual heterophoria (the resting state of vergence). In the present, large-scale replication we collected binocular eye movements (Eyelink II) for 94 participants who read 20 sentences monocularly and 20 sentences binocularly. Further, individual heterophorias were determined using three different optometric standards: objective eye tracking (EyeLink II at 60 cm), Maddox wing test (at 30 cm) and measures following the “Guidelines for the application of the Measuring and Correcting Methodology after H.-J. Haase” (MCH; at 6 m). Binocular eye movements showed typical pattern and we replicated (1) binocular advantages of about 25 ms for average fixation durations and (2) a reduction in binocular advantages when heterophoria increased – but only when heterophoria was identified by EyeLink II or Maddox wing measures; MCH measures of heterophoria did not affect binocular advantages in reading. For large heterophorias binocular reading even turned into a disadvantage. Implications for effect estimations and optometric testing will be discussed.
01A - Beitrag in wissenschaftlicher Zeitschrift
Do MCH prisms change asthenopic complaints when reading?
(DOZ-Verlag, 28.06.2024) Joss, Joëlle; Jainta, Stephanie
Purpose. Asthenopic symptoms mostly occur during demanding near-sighted tasks and are related to binocular symptoms (e.g. heterophoria), among others. Correction of symptomatic heterophoria with prismatic glasses is one way to treat the symptoms. This study investigates the effect of wearing a horizontal prismatic correction for 6 months. Material and Methods. A total of 87 subjects were assigned to a heterophoric prism group (N=32), a heterophoric control group (N= 31) or an orthophoric control group (N= 24) according to their MCH heterophoria. In the heterophoric prism group, the subjects were prescribed glasses with a prismatic correction for 6 months according to their distance correction; in contrast, the subjects in the heterophoric control group had to wear glasses without prismatic correction for the same period. The effect of the prisms on complaints due to asthenopic symptoms was investigated by comparing the total sum obtained in the CISS questionnaire at the beginning of the study and after 6 months (before and after wearing glasses) for the 3 groups. Results. A (long-term) prism effect was not apparent in the CISS total score. In both the heterophoric prism group and in the heterophoric control group, the CISS total score increased slightly and non-significantly after 6 months. When considering the heterophoric subjects with an increased CISS score at baseline, a nevertheless slight but non-significant decrease of symptoms was observed. All changes were observed in both the heterophoric prism group and the heterophoric control group. An additional analysis using binocular profiles showed a reduction in symptoms by numbers and specifically for subjects with reduced vergence facility. Conclusion. Wearing an individual, horizontal prismatic correction had no effect on the overall CISS-score for our test subjects. Further methods that allow a systematic recording of symptoms and optometric parameters are probably necessary to observe an effect. These could be binocular profiles that classify individuals according to their binocular parameters.
01A - Beitrag in wissenschaftlicher Zeitschrift
Do standard optometric measures predict binocular coordination during reading?
(Bern Open Publishing, 21.01.2021) Joss, Joëlle; Jainta, Stephanie
In reading, binocular eye movements are required for optimal visual processing and thus, in case of asthenopia or reading problems, standard orthoptic and optometric routines check individual binocular vision by a variety of tests. The present study therefore examines the predictive value of such standard measures of heterophoria, accommodative and vergence facility, AC/A-ratio, NPC and symptoms for binocular coordination parameters during reading. Binocular eye movements were recorded (EyeLink II) for 65 volunteers during a typical reading task and linear regression analyses related all parameters of binocular coordination to all above-mentioned optometric measures: while saccade disconjugacy was weakly predicted by vergence facility (15% explained variance), vergence facility, AC/A and symptoms scores predicted vergence drift (31%). Heterophoria, vergence facility and NPC explained 31% of fixation disparity and first fixation duration showed minor relations to symptoms (18%). In sum, we found only weak to moderate relationships, with expected, selective associations: dynamic parameter related to optometric tests addressing vergence dynamics, whereas the static parameter (fixation disparity) related mainly to heterophoria. Most surprisingly, symptoms were only loosely related to vergence drift and fixation duration, reflecting associations to a dynamic aspect of binocular eye movements in reading and potentially non-specific, overall but slight reading deficiency. Thus, the efficiency of optometric tests to predict binocular coordination during reading was low – questioning a simple, straightforward extrapolation of such test results to an overlearned, complex task.
01A - Beitrag in wissenschaftlicher Zeitschrift
Einblick. Nach mehr als zwei Jahren Forschung gibt es Neuigkeiten zur Wirkung prismatischer Korrekturen beim Lesen
(Galledia, 10/2022) Joss, Joëlle; Jainta, Stephanie
01B - Beitrag in Magazin oder Zeitung
Hygroscopic growth and water uptake kinetics of two-phase aerosol particles consisting of ammonium sulfate, adipic and humic acid mixtures
(Elsevier, 02/2007) Sjögren, Staffan; Gysel, Martin; Weingartner, Ernest; Baltensperger, Urs; Cubison, Michael J.; Coe, Hugh; Zardini, Alessandro A.; Marcolli, Claudia; Krieger, Ulrich K.; Peter, Thomas
The hygroscopic growth of solid aerosol particles consisting of mixtures of ammonium sulfate and either adipic acid or Aldrich humic acid sodium salt was characterized with a hygroscopicity tandem differential mobility analyzer and an electrodynamic balance. In particular, the time required for the aerosol particle phase and the surrounding water vapor to reach equilibrium at high relative humidity (RH) was investigated. Depending on the chemical composition of the particles, residence times of > 40 s were required to reach equilibrium at 85% RH, yielding up to a 7% reduction in the measured hygroscopic growth factors from measurements at 4 s residence time compared to measurements at equilibrium. We suggest that the solid organic compound, when present as the dominant component, encloses the water-soluble inorganic salt in veins and cavities, resulting in the observed slow water uptake. Comparison with predictions from the Zdanovskii-Stokes-Robinson relation shows enhanced water uptake of the mixed particles. This is explained with the presence of the salt solution in veins resulting in a negative curvature of the solution meniscus at the opening of the vein. In conclusion, it is important for studies of mixtures of water soluble compounds with insoluble material to allow for sufficient residence time at the specified humidity to reach equilibrium before the hygroscopicity measurements.
01A - Beitrag in wissenschaftlicher Zeitschrift
Relating asthenopic symptoms to optometric measures and parameters of binocular vision
(08/2022) Joss, Joëlle; Jainta, Stephanie
Asthenopic symptoms are related to heterophoria and problems of binocular vision. In a recent paper, we showed that vergence drift and fixation durations are related to symptoms (CISS-questionnaire), but optometric measures such as heterophoria, vergence or accommodative facility, AC/A-ratio or NPC did not significantly add to the explained variance of asthenopia. We re-analysed our data, in which binocular eye movements were recorded (EyeLink II) for 64 participants, and linear regression analyses related all parameters of binocular coordination (objective heterophoria, vergence drift, saccade disconjugacy, fixation disparity and fixation duration), and the above-mentioned optometric tests to 4 symptoms factors (eye comfort, reading process, image quality and fatigue), which we identified by a factor analysis of the CISS-questionnaire. Objective heterophoria and fixation duration predicted 20% of the variance in symptoms concerning the reading process (factor 2). Furthermore, fixation duration seems to be slightly, but not significantly, related to symptoms addressing fatigue (factor 4), whereas optometric tests are not significantly related to any asthenopia factor. Overall, objective measures during reading relate to asthenopic symptoms, however the lack of asthenopic symptoms prediction by daily optometric parameters is still unexplained. Therefore, further research is needed to find out suited optometric parameters to infer asthenopic symptoms.
06 - Präsentation
Trace metals in ambient air. Hourly size-segregated mass concentrations determined by synchrotron-XRF
(American Chemical Society, 28.06.2005) Bukowiecki, Nicolas; Hill, Matthias; Gehrig, Robert; Zwicky, Christoph N.; Lienemann, Peter; Hegedüs, Ferenc; Falkenberg, Gerald; Weingartner, Ernest; Baltensperger, Urs
Trace metals are ubiquitous in urban ambient air, with mass concentrations in the range of a few μg/m³ down to less than 100 pg/m³. To measure such low concentrations represents a challenge for chemical and physical analysis. In this study, ambient aerosol was collected in Zürich (Switzerland) in 1-h intervals and three size fractions (aerodynamic diameters 0.1−1 μm, 1−2.5 μm, and 2.5−10 μm), using a three-stage rotating drum impactor (RDI). The samples were analyzed by energy-dispersive Synchrotron radiation X-ray fluorescence spectrometry (SR-XRF) to obtain size-segregated hourly elemental aerosol mass concentrations for Cr, Mn, Fe, Cu, Zn, Br, and Pb, along with S, Cl, and Ca under the selected experimental conditions. The high sensitivity of SR-XRF allowed for detection limits of <50 pg/m³ for most of the above elements, with a net analysis time of only 15 s per sample. The data obtained with this technique illustrate that there is a considerable gain of relevant information when time resolution for measurements is increased from 1 day to 1 h. The individual size fractions of a specific element may show significantly different short-term patterns.
01A - Beitrag in wissenschaftlicher Zeitschrift
Verändern MKH-Prismen den binokularen Vorteil beim Lesen?
(DOZ-Verlag, 2022) Joss, Joëlle; Jainta, Stephanie
Zweck. Beim Lesen mit beiden Augen stellt sich ein binokularer Vorteil (kürzere Lese- und Fixationszeiten im Vergleich zu monokularem Lesen), welcher durch Prozesse der motorischen und sensorischen Fusion zustande kommt, ein. Der binokulare Vorteil beim Lesen ist zum Teil von der individuellen horizontalen Heterophorie abhängig und damit stellte sich die Frage, ob sich prismatische Korrektionen (bestimmt nach der MKH-Methode, zum Ausgleich einer Heterophorie) auf den binokularen Vorteil oder auf Parameter der binokularen Koordination beim Lesen auswirken. Material und Methoden. Wir haben die binokularen Augenbewegungen von 54 Personen mit einer individuellen horizontalen Heterophorie beim Lesen vermessen (Eyelink II): für (1) monokular, (2) binokular, (3) binokular mit Disparität (entsprechend MKH-Prisma) und (4) binokular mit Disparität nach sechs Monaten präsentierte, deutschsprachige Sätze (insg. 120). In der sechsmonatigen Pause zwischen Messung (3) und (4) trugen 29 Personen Brillen mit prismatischen Korrektionen, während 25 Personen als Kontrollgruppe fungierten. Ergebnisse. Unsere Daten zeigten einen klaren, signifikantenVorteil für binokulares Lesen für alle Personen, ohne dass eine kurzfristige Präsentation einer individuellen Disparität (analog eines MKH-Prismas) daran etwas änderte. Erst nach einer Prismentragezeit von sechs Monaten zeigte sich zusätzlich ein tendenziell größerer binokularer Vorteil in der „Prismengruppe“ im Vergleich zur „Kontrollgruppe“. Parallel dazu nahm die Kopplung der Augen (Diskonjunktion) leicht zu und die objektive Fixationsdisparität nahm signifikant ab. Fazit. Das Tragen einer individuellen prismatischen, horizontalen Korrektion (MKH) hatte für unsere Studienteilnehmer*innen einen Einfluss auf die binokulare Koordination beim Lesen und erhöhte gleichzeitig den binokularen Vorteil. Dieser eher mittel- bis langfristige Effekt von prismatischen Korrektionen ist neu und sollte in weiteren Studien vertieft untersucht werden.
01A - Beitrag in wissenschaftlicher Zeitschrift