The development of a spectroscopy device on a chip that could realize real-time fingerprinting with label-free and high-throughput detection of trace molecules represents one of the big challenges in ...sensing. Dual-comb spectroscopy (DCS) in the mid-infrared is a powerful technique offering high acquisition rates and signal-to-noise ratios through use of only a single detector with no moving parts. Here, we present a nanophotonic silicon-on-insulator platform designed for mid-infrared (mid-IR) DCS. A single continuous-wave low-power pump source generates two mutually coherent mode-locked frequency combs spanning from 2.6 to 4.1 μm in two silicon microresonators. A proof-of-principle experiment of vibrational absorption DCS in the liquid phase is achieved acquiring spectra of acetone spanning from 2900 to 3100 nm at 127-GHz (4.2-cm
) resolution. These results represent a significant step towards a broadband, mid-IR spectroscopy instrument on a chip for liquid/condensed matter phase studies.
Capturing complex 3D tissue physiology in vitro Griffith, Linda G; Swartz, Melody A
Nature reviews. Molecular cell biology,
200603, 2006-Mar, 2006-3-00, 20060301, Letnik:
7, Številka:
3
Journal Article
Recenzirano
The emergence of tissue engineering raises new possibilities for the study of complex physiological and pathophysiological processes in vitro. Many tools are now available to create 3D tissue models ...in vitro, but the blueprints for what to make have been slower to arrive. We discuss here some of the 'design principles' for recreating the interwoven set of biochemical and mechanical cues in the cellular microenvironment, and the methods for implementing them. We emphasize applications that involve epithelial tissues for which 3D models could explain mechanisms of disease or aid in drug development.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Tissue engineering can be used to restore, maintain, or enhance tissues and organs. The potential impact of this field, however, is far broader-in the future, engineered tissues could reduce the need ...for organ replacement, and could greatly accelerate the development of new drugs that may cure patients, eliminating the need for organ transplants altogether.
Organoid cultures are proving to be powerful in vitro models that closely mimic the cellular constituents of their native tissue. Organoids are typically expanded and cultured in a 3D environment ...using either naturally derived or synthetic extracellular matrices. Assessing the morphology and growth characteristics of these cultures has been difficult due to the many imaging artifacts that accompany the corresponding images. Unlike single cell cultures, there are no reliable automated segmentation techniques that allow for the localization and quantification of organoids in their 3D culture environment. Here we describe OrgaQuant, a deep convolutional neural network implementation that can locate and quantify the size distribution of human intestinal organoids in brightfield images. OrgaQuant is an end-to-end trained neural network that requires no parameter tweaking; thus, it can be fully automated to analyze thousands of images with no user intervention. To develop OrgaQuant, we created a unique dataset of manually annotated human intestinal organoid images with bounding boxes and trained an object detection pipeline using TensorFlow. We have made the dataset, trained model and inference scripts publicly available along with detailed usage instructions.
Epithelial organoids derived from human donor tissues are important tools in fields ranging from regenerative medicine to drug discovery. Organoid culture requires expansion of stem/progenitor cells ...in Matrigel, a tumor-derived extracellular matrix (ECM). An alternative completely synthetic ECM could improve reproducibility, clarify mechanistic phenomena, and enable human implantation of organoids. We designed synthetic ECMs with tunable biomolecular and biophysical properties to identify gel compositions supporting human tissue-derived stem/progenitor epithelial cells as enteroids and organoids starting with single cells rather than tissue fragments. The synthetic ECMs consist of 8-arm PEG-macromers modified with ECM-binding peptides and different combinations of integrin-binding peptides, crosslinked with peptides susceptible to matrix metalloprotease (MMP) degradation, and tuned to exhibit a range of biophysical properties. A gel containing an α2β1 integrin-binding peptide (GFOGER) and matrix binder peptides grafted to a 20 kDa 8-arm PEG macromer showed the most robust support of human duodenal and colon enteroids and endometrial organoids. In this synthetic ECM, human intestinal enteroids and endometrial organoids emerge from single cells and show cell-specific and apicobasal polarity markers upon differentiation. Intestinal enteroids, in addition, retain their proliferative capacity, are functionally responsive to basolateral stimulation, express canonical markers of intestinal crypt cells including Paneth cells, and can be serially passaged. The success of this synthetic ECM in supporting human postnatal organoid culture from multiple different donors and from both the intestine and endometrium suggests it may be broadly useful for other epithelial organoid culture.
We use the 2016 U.S. SEC tick size pilot to examine the effects of an increase in the minimum price variation on limit order book liquidity in NASDAQ-listed stocks on the NASDAQ exchange. For ...treatment stocks with an average pre-pilot quoted spread less than $0.05, the tick size increase is binding and leads to a significant decrease in liquidity in the limit order book. Specifically, the implied cost to trade at and away from the best bid and offer prices increases and the limit order book becomes less resilient – the amount of time required for a deviation in liquidity to return to its long-run mean. For treatment stocks with an average pre-pilot quoted spread of at least $0.05, the tick size increase is non-binding and leads to either a slight decrease, or no change in limit order book liquidity.
•We review the use of commercial bio-inoculants to increase plant uptake of phosphorus.•We examine microorganisms found within such bio-inoculants and their mode of action.•We propose a re-order of ...nomenclature to clarify the typology of bio-inoculants.•We conclude that the beneficial attributes of commercial bio-inoculants are unclear.•However, bio-inoculants could contribute to sustainable food production systems.
Meeting increasing global demand for food, fibre, and bioenergy requires efficient use of finite resources, and presents a key sustainability challenge to the agricultural industry, scientists and policy-makers. Increased interest in low-input agriculture in recent years has seen the growing development and use of commercial biological inoculants (bacteria and/or fungi) to increase the mobilisation of key nutrients, especially phosphorus (P), and enhance their availability to crop plants. Here, we review the terminology, composition and function of bio-inoculants and the many factors which impact on their efficacy for increasing P availability in different soil and plant environments. We conclude that the beneficial attributes of commercial bio-inoculants for integrated production systems are not clearly defined. Evidence to support their effectiveness is currently confounded by inadequate quality standards and insufficient knowledge of the underlying mechanisms, which have led to contradicting reports on field performance. There is, however, scope to engineer specific inoculant formulae for more sustainable P management in different system-soil-plant combinations, provided future research is properly structured to help understand the complexity and dynamism of microbial functioning and interactions in soils.
The generation of temporal cavity solitons in microresonators results in coherent low-noise optical frequency combs that are critical for applications in spectroscopy, astronomy, navigation or ...telecommunications. Breather solitons also form an important part of many different classes of nonlinear wave systems, manifesting themselves as a localized temporal structure that exhibits oscillatory behaviour. To date, the dynamics of breather solitons in microresonators remains largely unexplored, and its experimental characterization is challenging. Here we demonstrate the excitation of breather solitons in two different microresonator platforms based on silicon nitride and on silicon. We investigate the dependence of the breathing frequency on pump detuning and observe the transition from period-1 to period-2 oscillation. Our study constitutes a significant contribution to understanding the soliton dynamics within the larger context of nonlinear science.
In vitro tissue engineered models are poised to have significant impact on disease modeling and preclinical drug development. Reliable methods to induce microvascular networks in such ...microphysiological systems are needed to improve the size and physiological function of these models. By systematically engineering several physical and biomolecular properties of the cellular microenvironment (including crosslinking density, polymer density, adhesion ligand concentration, and degradability), we establish design principles that describe how synthetic matrix properties influence vascular morphogenesis in modular and tunable hydrogels based on commercial 8-arm poly (ethylene glycol) (PEG8a) macromers. We apply these design principles to generate endothelial networks that exhibit consistent morphology throughout depths of hydrogel greater than 1 mm. These PEG8a-based hydrogels have relatively high volumetric swelling ratios (>1.5), which limits their utility in confined environments such as microfluidic devices. To overcome this limitation, we mitigate swelling by incorporating a highly functional PEG-grafted alpha-helical poly (propargyl-l-glutamate) (PPLGgPEG) macromer along with the canonical 8-arm PEG8a macromer in gel formation. This hydrogel platform supports enhanced endothelial morphogenesis in neutral-swelling environments. Finally, we incorporate PEG8a-PPLGgPEG gels into microfluidic devices and demonstrate improved diffusion kinetics and microvascular network formation in situ compared to PEG8a-based gels.
Objective Our aim was to characterize peritoneal cytokine profiles in patients with infertility, with and without endometriosis, to illuminate potential differences in immune profiles that may ...reflect mechanistic differences between these two patient populations. Design Cross-sectional study. Setting University hospital and research center. Patient(s) Women undergoing laparoscopy for infertility investigation (n = 107). Intervention(s) Peritoneal fluid was collected during surgery. Clinical characteristics were registered preoperatively. Main Outcome Measure(s) We determined the concentration of 48 different cytokines from the peritoneal fluid with multiplex immunoassays. Associations between cytokines and clinical findings were assessed with logistic regression and partial least squares discriminant analyses (PLS-DA). Result(s) Concentrations of SCGF-β, IL-8, HGF, and MCP-1 were significantly higher, while IL-13 was significantly lower in the endometriosis group compared with the group without endometriosis. Multiple stepwise logistic regression identified a combination of SCGF-β, IL-13, and G-CSF concentrations that predicted the presence of endometriosis with 86% sensitivity and 67% specificity. PLS-DA identified a class of 11 cytokines (SCGF-β, HGF, IL-13, MCP-1, CTACK, MCP-3, M-CSF, LIF, IL-5, IL-9, and IFN-a2) that were more characteristic of endometriosis than nonendometriosis patients. Conclusion(s) By combining univariate and multivariate analyses, profiles of cytokines more likely to be enriched or depleted in infertility patients with endometriosis compared with those without endometriosis were identified. These findings may inform future analyses of pathophysiological mechanisms of endometriosis in infertile patients, including dysregulated Th1/Th2 response and mobilization and proliferation of hematopoietic stem cells.
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