Publications by authors named "David Trumper"

Rheology describes the flow of fluids from food and plastics, to coatings, adhesives, and 3D printing inks, and is commonly denoted by viscosity alone as a simplification. While viscometers adequately probe Newtonian (constant) viscosity, most fluids have complex viscosity, requiring tests over multiple shear rates, and transient measurements. As a result, rheometers are typically large, expensive, and require additional infrastructure (e.

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Recently, a GuMI gut microphysiological system has been established to coculture oxygen-intolerant () A2-165 with organoids-derived primary human colonic epithelium. This study aims to test if this GuMI system applies to different donors with different healthy states and uses metabolomics to reveal the role of gut microbes in modulating host- and diet-derived molecules in the gut lumen. Organoids-derived colonic monolayers were generated from an uninflamed region of diverticulitis, ulcerative colitis, and Crohn's disease patients and then integrated into the GuMI system to coculture with A2-165 for 2 to 4 days.

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This paper describes a novel bearingless split tooth flux reversal motor with integrated centrifugal blood pump. This motor has a magnet-free rotor, and is capable of operating at up to 3000 rpm with up to 100 mNm torque. The motor also has 50 N radial force capability for centering the rotor.

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This paper describes a position sensor with six degrees of freedom (DoF) measurement capability. This sensor is designed for the position sensing of the rotor in a bearingless slice motor to enable active control. The sensor is designed to fit entirely under the rotor and operates by accessing the rotor bottom surface only, enabling packaging of the pump on the top of the rotor.

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Article Synopsis
  • Chemotherapy dosing traditionally relies on patient weight and height, which often leads to significant variations in drug levels, potentially causing under- or overdosing.
  • A new closed-loop drug delivery system, known as CLAUDIA, can automatically adjust drug infusion rates to maintain target drug concentrations in patients, regardless of their individual pharmacokinetics.
  • Tests showed that CLAUDIA effectively kept the concentration of 5-fluorouracil within range, unlike conventional BSA-based dosing, and is also more cost-effective, with potential for rapid clinical implementation.
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Article Synopsis
  • Scientists created a special system called GuMI to study how gut microbes like F. prausnitzii interact with human immune cells and gut lining cells over a long time.
  • They found that immune cells called antigen-presenting cells (APCs) helped increase the levels of certain signaling molecules when present in the system with the gut lining and microbes.
  • The presence of CD4 naive T cells changed how the gut lining reacted to the microbes, showing that different immune cells play important roles in controlling how the gut responds to good bacteria and possible inflammation.
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Crosstalk of microbes with human gut epithelia and immune cells is crucial for gut health. However, there is no existing system for a long-term co-culture of human innate immune cells with epithelium and oxygen-intolerant commensal microbes, hindering the understanding of microbe-immune interactions in a controlled manner. Here, we establish a gut epithelium-microbe-immune microphysiological system to maintain the long-term continuous co-culture of with colonic epithelium, antigen-presenting cells (APCs, herein dendritic cells and macrophages), with CD4 naïve T cells circulating underneath the colonic epithelium.

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In this paper, we present a bearingless motor with a novel segmented dipole interior permanent magnet (IPM) slice rotor. The segmented dipole IPM rotor contains a unique pattern of interior permanent magnets arranged to generate a dipole air gap flux pattern. The magnets are encapsulated within an electrical steel rotor structure.

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We present a new configuration of bearingless slice motor that levitates and rotates a ring-shaped solid steel reluctance rotor. The rotor is 50 mm in diameter and has salient features on the outer surface. Symmetric sets of Halbach magnet arrays, mounted on the tips of stator teeth, establish a homopolar bias flux around the rotor.

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Slow progress in the fight against neurodegenerative diseases (NDs) motivates an urgent need for highly controlled in vitro systems to investigate organ-organ- and organ-immune-specific interactions relevant for disease pathophysiology. Of particular interest is the gut/microbiome-liver-brain axis for parsing out how genetic and environmental factors contribute to NDs. We have developed a mesofluidic platform technology to study gut-liver-cerebral interactions in the context of Parkinson's disease (PD).

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Background: The gut microbiome plays an important role in human health and disease. Gnotobiotic animal and cell-based models provide some informative insights into mechanistic crosstalk. However, there is no existing system for a long-term co-culture of a human colonic mucosal barrier with super oxygen-sensitive commensal microbes, hindering the study of human-microbe interactions in a controlled manner.

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Although the association between the microbiome and IBD and liver diseases is known, the cause and effect remain elusive. By connecting human microphysiological systems of the gut, liver, and circulating Treg and Th17 cells, we created a multi-organ model of ulcerative colitis (UC) ex vivo. The approach shows microbiome-derived short-chain fatty acids (SCFAs) to either improve or worsen UC severity, depending on the involvement of effector CD4 T cells.

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Objective: An infant born with long-gap esophageal atresia has its esophagus separated into two pouches, and typically undergoes multiple open-chest surgeries for esophageal reconstruction. In this paper, we study a possible approach for less invasive correction of long-gap esophageal atresia.

Methods: Our technique utilizes a magnet-tipped catheter with a piston on the end to push the esophageal pouch from the inside.

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Microphysiological systems (MPSs) are in vitro models that capture facets of in vivo organ function through use of specialized culture microenvironments, including 3D matrices and microperfusion. Here, we report an approach to co-culture multiple different MPSs linked together physiologically on re-useable, open-system microfluidic platforms that are compatible with the quantitative study of a range of compounds, including lipophilic drugs. We describe three different platform designs - "4-way", "7-way", and "10-way" - each accommodating a mixing chamber and up to 4, 7, or 10 MPSs.

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Article Synopsis
  • A new bearingless slice motor concept is introduced, which uses a levitating ring-shaped rotor made of D2 steel to perform rotations while maintaining stability.
  • The rotor remains suspended through magnetic fields, with a two-pole flux for stability and a separate six-pole flux for torque generation, allowing for effective decoupling of suspension and driving mechanisms.
  • A working prototype with a twelve-tooth stator and reflective optical sensors can levitate the rotor and achieve speeds of up to 1730 rpm, demonstrating maximum driving torque of around 2.7 mNm.
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A capability for analyzing complex cellular communication among tissues is important in drug discovery and development, and in vitro technologies for doing so are required for human applications. A prominent instance is communication between the gut and the liver, whereby perturbations of one tissue can influence behavior of the other. Here, we present a study on human gut-liver tissue interactions under normal and inflammatory contexts, via an integrative multi-organ platform comprising human liver (hepatocytes and Kupffer cells), and intestinal (enterocytes, goblet cells, and dendritic cells) models.

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Vascular systems grow and remodel in response to not only metabolic needs, but also mechanical influences as well. Here, we investigated the influence of tissue-level mechanical forces on the patterning and structure of the chick chorioallantoic membrane (CAM) microcirculation. A dipole stretch field was applied to the CAM using custom computer-controlled servomotors.

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We present a novel charge amplifier, with a robust feedback circuit and a method for compensating piezoelectric actuator's hysteresis at low frequencies. The amplifier uses a modified feedback circuit which improves robustness to the addition of series load impedance such as in cabling. We also describe a hybrid hysteresis compensation method for enabling the charge amplifier to reduce hysteresis at low frequencies.

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