scholarly journals Effect of nasal airway nonlinearities on oscillometric resistance measurements in infants

2020 ◽  
Vol 129 (3) ◽  
pp. 591-598
Author(s):  
Bence L. Radics ◽  
Gergely Makan ◽  
Thibault Coppens ◽  
Nicolas André ◽  
Cyril Page ◽  
...  
Keyword(s):  
Respiratory System ◽  
Upper Airway ◽  
Nasal Airway ◽  
Nonlinearity Error ◽  
Flow Acceleration ◽  
In Vitro Measurements ◽  
3D Printed ◽  
Respiratory System Resistance

Oscillometric measurements of respiratory system resistance (Rrs) in infants are usually made via the nasal pathways, which not only significantly contribute to overall Rrs but also introduce marked flow acceleration-dependent distortions. Here, we propose a method for correcting flow acceleration-dependent nonlinearity error based on in vitro measurements in 3D-printed upper airway casts of infants as well as in vivo measurements. This correction can be adapted to estimate Rrs from a single intrabreath oscillometric measurement.

scholarly journals Fabrication of 3D-Printed Interpenetrating Hydrogel Scaffolds for Promoting Chondrogenic Differentiation

Polymers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 2146
Author(s):  
Jian Guan ◽  
Fu-zhen Yuan ◽  
Zi-mu Mao ◽  
Hai-lin Zhu ◽  
Lin Lin ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Elastic Modulus ◽  
Chondrogenic Differentiation ◽  
Marker Genes ◽  
Self Healing ◽  
Polyethylene Glycol Diacrylate ◽  
3D Microenvironment ◽  
3D Printed

The limited self-healing ability of cartilage necessitates the application of alternative tissue engineering strategies for repairing the damaged tissue and restoring its normal function. Compared to conventional tissue engineering strategies, three-dimensional (3D) printing offers a greater potential for developing tissue-engineered scaffolds. Herein, we prepared a novel photocrosslinked printable cartilage ink comprising of polyethylene glycol diacrylate (PEGDA), gelatin methacryloyl (GelMA), and chondroitin sulfate methacrylate (CSMA). The PEGDA-GelMA-CSMA scaffolds possessed favorable compressive elastic modulus and degradation rate. In vitro experiments showed good adhesion, proliferation, and F-actin and chondrogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) on the scaffolds. When the CSMA concentration was increased, the compressive elastic modulus, GAG production, and expression of F-actin and cartilage-specific genes (COL2, ACAN, SOX9, PRG4) were significantly improved while the osteogenic marker genes of COL1 and ALP were decreased. The findings of the study indicate that the 3D-printed PEGDA-GelMA-CSMA scaffolds possessed not only adequate mechanical strength but also maintained a suitable 3D microenvironment for differentiation, proliferation, and extracellular matrix production of BMSCs, which suggested this customizable 3D-printed PEGDA-GelMA-CSMA scaffold may have great potential for cartilage repair and regeneration in vivo.

scholarly journals Thrombus Imaging Using 3D Printed Middle Cerebral Artery Model and Preclinical Imaging Techniques: Application to Thrombus Targeting and Thrombolytic Studies

Pharmaceutics ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1207
Author(s):  
Andrea Vítečková Wünschová ◽  
Adam Novobilský ◽  
Jana Hložková ◽  
Peter Scheer ◽  
Hana Petroková ◽  
...  
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Imaging Techniques ◽  
Barium Sulphate ◽  
Flow Conditions ◽  
Preclinical Imaging ◽  
Blood Clots ◽  
3D Printed

Diseases with the highest burden for society such as stroke, myocardial infarction, pulmonary embolism, and others are due to blood clots. Preclinical and clinical techniques to study blood clots are important tools for translational research of new diagnostic and therapeutic modalities that target blood clots. In this study, we employed a three-dimensional (3D) printed middle cerebral artery model to image clots under flow conditions using preclinical imaging techniques including fluorescent whole-body imaging, magnetic resonance imaging (MRI), and computed X-ray microtomography (microCT). Both liposome-based, fibrin-targeted, and non-targeted contrast agents were proven to provide a sufficient signal for clot imaging within the model under flow conditions. The application of the model for clot targeting studies and thrombolytic studies using preclinical imaging techniques is shown here. For the first time, a novel method of thrombus labeling utilizing barium sulphate (Micropaque®) is presented here as an example of successfully employed contrast agents for in vitro experiments evaluating the time-course of thrombolysis and thus the efficacy of a thrombolytic drug, recombinant tissue plasminogen activator (rtPA). Finally, the proof-of-concept of in vivo clot imaging in a middle cerebral artery occlusion (MCAO) rat model using barium sulphate-labelled clots is presented, confirming the great potential of such an approach to make experiments comparable between in vitro and in vivo models, finally leading to a reduction in animals needed.

Development of a Novel 3D Bioprinted In Vitro Nano Bone Model for Breast Cancer Bone Metastasis Study

2014 ◽  
Vol 1724 ◽  
Author(s):  
Benjamin Holmes ◽  
Wei Zhu ◽  
Lijie Grace Zhang
Keyword(s):  
Breast Cancer ◽  
Bone Metastasis ◽  
Metastatic Breast ◽  
Bone Microstructure ◽  
Bone Model ◽  
Skeletal Complications ◽  
3D Printed ◽  
Breast Cancer Bone Metastasis

ABSTRACTBreast cancer (BrCa) is the second commonest cause of cancer-related deaths in women. The metastatic breast cancer exhibits a high affinity to bone, leading to debilitating skeletal complications associated with significant morbidity and poor prognosis. Traditional in vitro and in vivo BrCa bone metastasis models contain many inherent limitations with regards to controllability, reproducibility, and flexibility of design. Thus, the objective of this research is to use a 3D bioprinting system and nanomaterials to recreate a biomimetic and tunable bone model suitable for the effective simulation and study of metastatic BrCa invading and colonizing a bone environment. For this purpose, we designed and 3D printed a series of scaffolds, comprised of a bone microstructure and nano hydroxyapatites (nHA, inorganic nano components in bone). The size and geometry of the bone microstructure was varied with 250 and 150 µm pores, in repeating square and hexagon patterns, for a total of four different pore geometries. 3D bioprinted scaffolds were subsequently conjugated with nHA, using an acetylation chemical functionalization process and then characterized by scanning electron microscope (SEM). SEM imaging showed that our designed microfeatures were printable with the predesigned resolutions described above. Imaging further confirmed that acetylation effectively attached nHA to the surface of scaffolds and induced a nanoroughness. Metastatic BrCa cell 4 h adhesion and 1, 3 and 5 day proliferation were investigated in the bone model in vitro. The cell adhesion and proliferation results showed that all scaffolds are cytocompatible for BrCa cell growth; in particular the nHA scaffolds with small hexagonal pores had the highest cell density. Given this data, it can be stipulated that our 3D printed nHA scaffolds may make effective biomimetic environments for studying BrCa bone metastasis.

Correlation of in vivo and in vitro measurements of sun protection factor

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
M.-T. Sheu ◽  
C.-W. Lin ◽  
M.-C. Huang ◽  
C.-H. Shen ◽  
H.-O. Ho
Keyword(s):  
Sun Protection ◽  
Protection Factor ◽  
In Vitro Measurements ◽  
Sun Protection Factor

scholarly journals Nanoclay-based 3D printed scaffolds promote vascular ingrowth ex vivo and generate bone mineral tissue in vitro and in vivo

2020 ◽  
Vol 12 (3) ◽  
pp. 035010 ◽  
Author(s):  
Gianluca Cidonio ◽  
Michael Glinka ◽  
Yang-Hee Kim ◽  
Janos M Kanczler ◽  
Stuart A Lanham ◽  
...  
Keyword(s):  
Bone Mineral ◽  
Ex Vivo ◽  
3D Printed

scholarly journals Advances in Photoacoustic Noninvasive Glucose Testing

1999 ◽  
Vol 45 (9) ◽  
pp. 1587-1595 ◽  
Author(s):  
Hugh A MacKenzie ◽  
Helen S Ashton ◽  
Stephen Spiers ◽  
Yaochun Shen ◽  
Scott S Freeborn ◽  
...  
Keyword(s):  
Glucose Measurement ◽  
Oral Glucose ◽  
Physiological Factors ◽  
Glucose Testing ◽  
In Vivo Experiments ◽  
In Vitro Measurements ◽  
Clinical Measurements ◽  
Blood Analytes

Abstract We report here on in vitro and in vivo experiments that are intended to explore the feasibility of photoacoustic spectroscopy as a tool for the noninvasive measurement of blood glucose. The in vivo results from oral glucose tests on eight subjects showed good correlation with clinical measurements but indicated that physiological factors and person-to-person variability are important. In vitro measurements showed that the sensitivity of the glucose measurement is unaffected by the presence of common blood analytes but that there can be substantial shifts in baseline values. The results indicate the need for spectroscopic data to develop algorithms for the detection of glucose in the presence of other analytes.

scholarly journals Intraperitoneal pressure: Stability over time and validation of Durand’s measurement method

2020 ◽  
pp. 089686082097312
Author(s):  
Alicia Sobrino-Pérez ◽  
Alfonso Pérez-Escudero ◽  
Lucila Fernández-Arroyo ◽  
Ana Dorado-García ◽  
Berta Martín-Alcón ◽  
...  
Keyword(s):  
Peritoneal Dialysis ◽  
Venous Pressure ◽  
Relevant Parameter ◽  
Pressure System ◽  
Intraperitoneal Pressure ◽  
In Vitro Measurements ◽  
Long Timescales ◽  
Over Time

Intraperitoneal pressure (IPP) is gaining consideration as a relevant parameter of peritoneal dialysis (PD) in adults, although many of its aspects are still pending clarification. We address here its stability over time and the validity of the usual method of clinical measurement, as proposed by Durand in 1992 but never specifically validated. We performed this validation by comparing Durand’s method and direct measurements with a central venous pressure system. We performed a total of 250 measurement pairs in 50 patients with different intraperitoneal volumes plus in-vitro measurements with a simulated peritoneum. Absolute differences between the two systems in vivo were 0.87 ± 0.91 cmH2O (range 0–5 cmH2O); only 6.4% of them were ≥3 cmH2O. In vitro results for both methods were identical. We also compared IPP measurements in the same patient separated by 1–4 h (514 measurement pairs in 136 patients), 1 week (92 pairs in 92 patients), and 2 years (34 pairs in 17 patients). Net differences of measurements separated by hours or 1 week were close to 0 cmH2O, with oscillations of 1.5 cmH2O in hours and 2.3 cmH2O in 1 week. IPP measured 2 years apart presented a net decrease of 2.5 ± 4.9 cmH2O, without correlation with body mass index changes or any other usual parameter of PD. In hours, 7% of IPP differences were >3 cmH2O, 22% in 1 week, and 50% in 2 years. In conclusion, Durand’s method is precise enough to measure IPP in peritoneal dialysis. This parameter is not stable over long timescales, so it is necessary to use recent measurements.

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