Experimental Investigation of the Spread of Airborne CFU in a Research-OR under Different Air Flow Regimes using Tracer Particles

Aim of this experimental study is to compare different types of ventilation in operating rooms (OR) regarding the highest possible patient protection against airborne germs based on particle counting. Tracer particles with the size of the airborne colony-forming units (CFU) occurring in OR shall be generated to derive representative statements about the removal of germs. In addition, they origin from aerosol generators mounted on heated person simulators to obtain a realistic dispersion of the contamination. It can be shown that the aerosol generators designed produce particles in the relevant size classes of the airborne germs emitted by OR personnel.publishedVersio

Ice nucleation efficiency of natural dust samples in the immersion mode

A total of 12 natural surface dust samples, which were surface-collected on four continents, most of them in dust source regions, were investigated with respect to their ice nucleation activity. Dust collection sites were distributed across Africa, South America, the Middle East, and Antarctica. Mineralogical composition has been determined by means of X-ray diffraction. All samples proved to be mixtures of minerals, with major contributions from quartz, calcite, clay minerals, K-feldspars, and (Na, Ca)-feldspars. Reference samples of these minerals were investigated with the same methods as the natural dust samples. Furthermore, Arizona test dust (ATD) was re-evaluated as a benchmark. Immersion freezing of emulsion and bulk samples was investigated by differential scanning calorimetry. For emulsion measurements, water droplets with a size distribution peaking at about 2 µm, containing different amounts of dust between 0.5 and 50 wt % were cooled until all droplets were frozen. These measurements characterize the average freezing behaviour of particles, as they are sensitive to the average active sites present in a dust sample. In addition, bulk measurements were conducted with one single 2 mg droplet consisting of a 5 wt % aqueous suspension of the dusts/minerals. These measurements allow the investigation of the best ice-nucleating particles/sites available in a dust sample. All natural dusts, except for the Antarctica and ATD samples, froze in a remarkably narrow temperature range with the heterogeneously frozen fraction reaching 10 % between 244 and 250 K, 25 % between 242 and 246 K, and 50 % between 239 and 244 K. Bulk freezing occurred between 255 and 265 K. In contrast to the natural dusts, the reference minerals revealed ice nucleation temperatures with 2–3 times larger scatter. Calcite, dolomite, dolostone, and muscovite can be considered ice nucleation inactive. For microcline samples, a 50 % heterogeneously frozen fraction occurred above 245 K for all tested suspension concentrations, and a microcline mineral showed bulk freezing temperatures even above 270 K. This makes microcline (KAlSi3O8) an exceptionally good ice-nucleating mineral, superior to all other analysed K-feldspars, (Na, Ca)-feldspars, and the clay minerals. In summary, the mineralogical composition can explain the observed freezing behaviour of 5 of the investigated 12 natural dust samples, and partly for 6 samples, leaving the freezing efficiency of only 1 sample not easily explained in terms of its mineral reference components. While this suggests that mineralogical composition is a major determinant of ice-nucleating ability, in practice, most natural samples consist of a mixture of minerals, and this mixture seems to lead to remarkably similar ice nucleation abilities, regardless of their exact composition, so that global models, in a first approximation, may represent mineral dust as a single species with respect to ice nucleation activity. However, more sophisticated representations of ice nucleation by mineral dusts should rely on the mineralogical composition based on a source scheme of dust emissions

Handbuch mobile Frühstücksverpflegung

Version 2.0_Frühling_2018 Weitere Informationen unter: https://www.zhaw.ch/de/lsfm/institute-zentren/ifm/ueber-uns/hospitality-management-und-consumer-fm/fm-in-healthcare/spitalgastronomie

Identification of tagitinin C from Tithonia diversifolia as antitrypanosomal compound using bioactivity-guided fractionation

Tithonia diversifolia (Asteraceae), is used as traditional medicine in tropical countries for the treatment of various diseases, including malaria. Although numerous studies have assessed the antimalarial properties, nothing is known about the effect of T. diversifolia extracts on trypanosomiasis. In this study extracts of T. diversifolia aerial parts were evaluated for their bioactivity against Trypanosoma brucei. The activity was studied against bloodstream forms of T. brucei (TC221), as well as against mammalian cells (BALB/3T3 mouse fibroblasts), as a counter-screen for toxicity. Both methanolic and aqueous extracts showed significant effects with IC50 values of 1.1 and 2.2\u3bcg/mL against T. brucei (TC221) and 5.2 and 3.7\u3bcg/mL against BALB/3T3 cells, respectively. A bioassay-guided fractionation on the methanolic extract yielded in identification of active fractions (F8 and F9) with IC50 values of 0.41 and 0.43\u3bcg/mL, respectively, against T. brucei (TC221) and 1.4 and 1.5\u3bcg/mL, respectively, against BALB/3T3 cells,. The phytochemical composition of the extracts and the purified fractions were investigated using HPLC-ESI-MS/MS and 1D and 2D NMR spectra showing the presence of sesquiterpene lactones that in turn were subjected to the isolation procedure. Tagitinin A and C were rather active but the latter presented a very strong inhibition on T. brucei (TC221) with an IC50 value of 0.0042\u3bcg/mL. This activity was 4.5 times better than that of the reference drug suramin. The results of this study shed light on the antitrypanosomal effects of T. diversifolia extracts and highlighted tagitinin C as one of the possible responsible for this effect. Further structure activity relationships studies on tagitinins are needed to consider this sesquiterpenes as lead compounds for the development of new antitrypanosomal drugs

Long‐term safety, efficacy, and quality of life in patients with juvenile idiopathic arthritis treated with intravenous abatacept for up to seven years

ClinicalTrials.gov identifier: NCT00095173[Abstract] Objective. The efficacy and safety of abatacept in patients with juvenile idiopathic arthritis (JIA) who experienced an inadequate response to disease‐modifying antirheumatic drugs were previously established in a phase III study that included a 4‐month open‐label lead‐in period, a 6‐month double‐blind withdrawal period, and a long‐term extension (LTE) phase. The aim of this study was to present the safety, efficacy, and patient‐reported outcomes of abatacept treatment (10 mg/kg every 4 weeks) during the LTE phase, for up to 7 years of followup. Methods. Patients enrolled in the phase III trial could enter the open‐label LTE phase if they had not achieved a response to treatment at month 4 or if they had received abatacept or placebo during the double‐blind period. Results. One hundred fifty‐three (80.5%) of 190 patients entered the LTE phase, and 69 patients (36.3%) completed it. The overall incidence rate (events per 100 patient‐years) of adverse events decreased during the LTE phase (433.61 events during the short‐term phase [combined lead‐in and double‐blind periods] versus 132.39 events during the LTE phase). Similar results were observed for serious adverse events (6.82 versus 5.60), serious infections (1.13 versus 1.72), malignancies (1.12 versus 0), and autoimmune events (2.26 versus 1.18). American College of Rheumatology (ACR) Pediatric 30 (Pedi 30) responses, Pedi 70 responses, and clinically inactive disease status were maintained throughout the LTE phase in patients who continued to receive therapy. Improvements in the Child Health Questionnaire physical and psychosocial summary scores were maintained over time. Conclusion. Long‐term abatacept treatment for up to 7 years was associated with consistent safety, sustained efficacy, and quality‐of‐life benefits in patients with JIA

Systematic Development of Physical Hypermedia Applications

In this paper we present a model-based approach for the development of physical hypermedia applications, i.e. those mobile (Web) applications in which physical and digital objects are related and explored using the hypermedia paradigm. We describe an extension of the Object-Oriented Hypermedia Design Method (OOHDM) and present an improvement of the popular Model-View-Controller (MVC) metaphor to incorporate the concept of located object; we illustrate the idea with a framework implementation using Jakarta Struts. We first review the state of the art of this kind of software systems, stressing the need of a systematic design and implementation approach; we briefly present a light extension to the OOHDM design approach, incorporating physical objects and “walkable” links. We next present a Web application framework for deploying physical hypermedia software and show an example of use. We evaluate our approach and finally we discuss some further work we are pursuing

A standardized and reproducible method to measure decision-making in mice.

Abstract Progress in neuroscience is hindered by poor reproducibility of mouse behavior. Here we show that in a visual decision making task, reproducibility can be achieved by automating the training protocol and by standardizing experimental hardware, software, and procedures. We trained 101 mice in this task across seven laboratories at six different research institutions in three countries, and obtained 3 million mouse choices. In trained mice, variability in behavior between labs was indistinguishable from variability within labs. Psychometric curves showed no significant differences in visual threshold, bias, or lapse rates across labs. Moreover, mice across laboratories adopted similar strategies when stimulus location had asymmetrical probability that changed over time. We provide detailed instructions and open-source tools to set up and implement our method in other laboratories. These results establish a new standard for reproducibility of rodent behavior and provide accessible tools for the study of decision making in mice

Zum kontaminierten Raumvolumen von Partikel- und Wärmequellen in laminarer Verdrängungsströmung

In Räumen mit laminarer Verdrängungsströmung von oben ist die Strömungsstabilität für den bestimmungsgemäßen Betrieb entscheidend. Diese wird durch Wärmequellen im Raum, die gleichzeitig Partikelquellen sind, gestört. Ein kontaminiertes Raumvolumen bildet sich um die Wärmequelle aus, welches den Produkt- und Personenschutz gefährdet. Das Ziel der vorliegenden Arbeit besteht darin, eine Stabilitätsgrenze für eine zylinderförmige Wärmequelle in laminarer Verdrängungsströmung von oben festzulegen, bei der die Strömungsstabililät gewährleistet ist. Ein mathematisches Modell wird entwickelt, das die Abschätzung der geometrischen Ausdehnung des kontaminierten Raumvolumens ermöglicht. Als zentrale Einflussgrößen werden die konvektive Wärmeleistung, der Radius und die Höhe der Wärmequelle sowie die Zuluftgeschwindigkeit der Verdrängungsströmung betrachtet. Mittels laseroptischer Messverfahren und numerischen Strömungssimulationen wird die Ausdehnung des kontaminierten Raumvolumens bei Variation dieser Einflussgrößen quantifiziert und ein Stabilitätskriterium abgeleitet. Die Arbeit liefert einen funktionalen Zusammenhang zwischen den Einflussgrößen und der Ausdehnung des kontaminierten Raumvolumens. Die Ergebnisse ermöglichen die bedarfsgerechte Auslegung der Zuluftgeschwindigkeit an die Lasten im Raum, was im Betrieb der Reinraumanlage zu erheblichen energetischen Einsparungen führt

Contaminated volume of particles and heat sources in laminar unidirectional flow

In Räumen mit laminarer Verdrängungsströmung von oben ist die Strömungsstabilität für den bestimmungsgemäßen Betrieb entscheidend. Diese wird durch Wärmequellen im Raum, die gleichzeitig Partikelquellen sind, gestört. Ein kontaminiertes Raumvolumen bildet sich um die Wärmequelle aus, welches den Produkt- und Personenschutz gefährdet. Das Ziel der vorliegenden Arbeit besteht darin, eine Stabilitätsgrenze für eine zylinderförmige Wärmequelle in laminarer Verdrängungsströmung von oben festzulegen, bei der die Strömungsstabililät gewährleistet ist. Ein mathematisches Modell wird entwickelt, das die Abschätzung der geometrischen Ausdehnung des kontaminierten Raumvolumens ermöglicht. Als zentrale Einflussgrößen werden die konvektive Wärmeleistung, der Radius und die Höhe der Wärmequelle sowie die Zuluftgeschwindigkeit der Verdrängungsströmung betrachtet. Mittels laseroptischer Messverfahren und numerischen Strömungssimulationen wird die Ausdehnung des kontaminierten Raumvolumens bei Variation dieser Einflussgrößen quantifiziert und ein Stabilitätskriterium abgeleitet. Die Arbeit liefert einen funktionalen Zusammenhang zwischen den Einflussgrößen und der Ausdehnung des kontaminierten Raumvolumens. Die Ergebnisse ermöglichen die bedarfsgerechte Auslegung der Zuluftgeschwindigkeit an die Lasten im Raum, was im Betrieb der Reinraumanlage zu erheblichen energetischen Einsparungen führt.In rooms with laminar unidirectional flow from above, a stable flow is essential for proper operation. This flow is interfered by heat sources, which also emit particles. A contaminated volume forms around the heat source, endangering product and personal protection. The aim of the present work is to establish a stability limit for a cylindrical heat source in laminar unidirectional flow from above, at which the flow stability is ensured. A mathematical model is developed in order to allow the estimation of the geometric expansion of the contaminated volume. The convective heat output, the radius and the height of the heat source as well as the supply air velocity of the unidirectional flow are regarded as central influencing variables. With use of laser-optical measurement methods and numerical flow simulations, the dimension of the contaminated volume is quantified by varying the influencing variables. Based on this, a stability criterion is derived. The work provides a functional correlation between the influencing variables and the dimension of the contaminated volume. The results allow an adaptation of the supply air velocity according to the loads in the room, which leads to considerable energy savings in the operation of the clean room system

Experimental Investigation of the Spread of Airborne CFU in a Research-OR under Different Air Flow Regimes using Tracer Particles

Aim of this experimental study is to compare different types of ventilation in operating rooms (OR) regarding the highest possible patient protection against airborne germs based on particle counting. Tracer particles with the size of the airborne colony-forming units (CFU) occurring in OR shall be generated to derive representative statements about the removal of germs. In addition, they origin from aerosol generators mounted on heated person simulators to obtain a realistic dispersion of the contamination. It can be shown that the aerosol generators designed produce particles in the relevant size classes of the airborne germs emitted by OR personnel