| 1. |
- Zhang, Y. S., et al.
(author)
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Multisensor-integrated organs-on-chips platform for automated and continual in situ monitoring of organoid behaviors
- 2017
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In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 114:12, s. E2293-E2302
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Journal article (peer-reviewed)abstract
- Organ-on-a-chip systems areminiaturizedmicrofluidic 3D human tissue and organ models designed to recapitulate the important biological and physiological parameters of their in vivo counterparts. They have recently emerged as a viable platform for personalized medicine and drug screening. These in vitro models, featuring biomimetic compositions, architectures, and functions, are expected to replace the conventional planar, static cell cultures and bridge the gap between the currently used preclinical animal models and the human body. Multiple organoid models may be further connected together through the microfluidics in a similar manner in which they are arranged in vivo, providing the capability to analyze multiorgan interactions. Although a wide variety of human organ-on-a-chip models have been created, there are limited efforts on the integration of multisensor systems. However, in situ continual measuring is critical in precise assessment of the microenvironment parameters and the dynamic responses of the organs to pharmaceutical compounds over extended periods of time. In addition, automated and noninvasive capability is strongly desired for long-term monitoring. Here, we report a fully integrated modular physical, biochemical, and optical sensing platform through a fluidics-routing breadboard, which operates organ-on-a-chip units in a continual, dynamic, and automated manner.We believe that this platform technology has paved a potential avenue to promote the performance of current organ-on-a-chip models in drug screening by integrating a multitude of real-time sensors to achieve automated in situ monitoring of biophysical and biochemical parameters.
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| 2. |
- Naafs, B. D. A., et al.
(author)
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Introducing global peat-specific temperature and pH calibrations based on brGDGT bacterial lipids
- 2017
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In: Geochimica et Cosmochimica Acta. - : PERGAMON-ELSEVIER SCIENCE LTD. - 0016-7037 .- 1872-9533. ; 208, s. 285-301
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Journal article (peer-reviewed)abstract
- Glycerol dialkyl glycerol tetraethers (GDGTs) are membrane-spanning lipids from Bacteria and Archaea that are ubiquitous in a range of natural archives and especially abundant in peat. Previous work demonstrated that the distribution of bacterial branched GDGTs (brGDGTs) in mineral soils is correlated to environmental factors such as mean annual air temperature (MAAT) and soil pH. However, the influence of these parameters on brGDGT distributions in peat is largely unknown. Here we investigate the distribution of brGDGTs in 470 samples from 96 peatlands around the world with a broad mean annual air temperature (-8 to 27 degrees C) and pH (3-8) range and present the first peat-specific brGDGT-based temperature and pH calibrations. Our results demonstrate that the degree of cyclisation of brGDGTs in peat is positively correlated with pH, pH = 2.49 x CBTpeat + 8.07 (n = 51, R-2 = 0.58, RMSE = 0.8) and the degree of methylation of brGDGTs is positively correlated with MAAT, MAAT(peat) (degrees C) = 52.18 x MBT'(5me) - 23.05 (n = 96, R-2 = 0.76, RMSE = 4.7 degrees C). These peat-specific calibrations are distinct from the available mineral soil calibrations. In light of the error in the temperature calibration (similar to 4.7 degrees C), we urge caution in any application to reconstruct late Holocene climate variability, where the climatic signals are relatively small, and the duration of excursions could be brief. Instead, these proxies are well-suited to reconstruct large amplitude, longer-term shifts in climate such as deglacial transitions. Indeed, when applied to a peat deposit spanning the late glacial period (similar to 15.2 kyr), we demonstrate that MAAT(peat) yields absolute temperatures and relative temperature changes that are consistent with those from other proxies. In addition, the application of MAAT(peat) to fossil peat (i.e. lignites) has the potential to reconstruct terrestrial climate during the Cenozoic. We conclude that there is clear potential to use brGDGTs in peats and lignites to reconstruct past terrestrial climate.
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| 3. |
- Albani, S, et al.
(author)
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Twelve thousand years of dust : the Holocene global dust cycle constrained by natural archives
- 2015
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In: Climate of the Past. - : Copernicus GmbH. - 1814-9324 .- 1814-9332. ; 11:6, s. 869-903
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Journal article (peer-reviewed)abstract
- Mineral dust plays an important role in the climate system by interacting with radiation, clouds, and biogeochemical cycles. In addition, natural archives show that the dust cycle experienced variability in the past in response to global and local climate change. The compilation of the DIRTMAP paleodust datasets in the last two decades provided a target for paleoclimate models that include the dust cycle, following a time slice approach. We propose an innovative framework to organize a paleodust dataset that moves on from the positive experience of DIRTMAP and takes into account new scientific challenges, by providing a concise and accessible dataset of temporally resolved records of dust mass accumulation rates and particle grain-size distributions. We consider data from ice cores, marine sediments, loess/paleosol sequences, lake sediments, and peat bogs for this compilation, with a temporal focus on the Holocene period. This global compilation allows investigation of the potential, uncertainties and confidence level of dust mass accumulation rates reconstructions, and highlights the importance of dust particle size information for accurate and quantitative reconstructions of the dust cycle. After applying criteria that help to establish that the data considered represent changes in dust deposition, 43 paleodust records have been identified, with the highest density of dust deposition data occurring in the North Atlantic region. Although the temporal evolution of dust in the North Atlantic appears consistent across several cores and suggest that minimum dust fluxes are likely observed during the Early to mid-Holocene period (6000–8000 years ago), the magnitude of dust fluxes in these observations is not fully consistent, suggesting that more work needs to be done to synthesize datasets for the Holocene. Based on the data compilation, we used the Community Earth System Model to estimate the mass balance and variability of the global dust cycle during the Holocene, with dust load ranging from 17.1 to 20.5 Tg between 2000 and 10 000 years ago, and a minimum in the Early to Mid-Holocene (6000–8000 years ago).
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| 4. |
- Shaegh, S. A. M., et al.
(author)
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A microfluidic optical platform for real-time monitoring of pH and oxygen in microfluidic bioreactors and organ-on-chip devices
- 2016
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In: Biomicrofluidics. - : American Institute of Physics (AIP). - 1932-1058. ; 10:4
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Journal article (peer-reviewed)abstract
- There is a growing interest to develop microfluidic bioreactors and organ-on-chipplatforms with integrated sensors to monitor their physicochemical properties and tomaintain a well-controlled microenvironment for cultured organoids. Conventionalsensing devices cannot be easily integrated with microfluidic organ-on-chip systemswith low-volume bioreactors for continual monitoring. This paper reports on thedevelopment of a multi-analyte optical sensing module for dynamic measurementsof pH and dissolved oxygen levels in the culture medium. The sensing system wasconstructed using low-cost electro-optics including light-emitting diodes and siliconphotodiodes. The sensing module includes an optically transparent window formeasuring light intensity, and the module could be connected directly to a perfusionbioreactor without any specific modifications to the microfluidic device design. Acompact, user-friendly, and low-cost electronic interface was developed to controlthe optical transducer and signal acquisition from photodiodes. The platformenabled convenient integration of the optical sensing module with a microfluidicbioreactor. Human dermal fibroblasts were cultivated in the bioreactor, and thevalues of pH and dissolved oxygen levels in the flowing culture medium were measuredcontinuously for up to 3 days. Our integrated microfluidic system providesa new analytical platform with ease of fabrication and operation, which can beadapted for applications in various microfluidic cell culture and organ-on-chipdevices.
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