The musculoskeletal loading profile of the thumb during pipetting based on tendon displacement

HYKYHT: A versatile, affordable, and open-source 3D-printed liquid aspiration system

This paper aims to provide the details for making affordable single and multichannel liquid aspirators for wet labs. A liquid aspirator is a basic laboratory device that can cost several hundred Euros. We present a < €25 3D print solution that performs equally well in daily lab routines and is compatible with various vacuum sources, including an aquarium pump or household vacuum cleaner. Presently, commercial aspirators cost more than a decent entry-level 3D printer capable of producing all the parts listed in this manuscript. The models were designed with Tinkercad, with easy printing and minimal support in mind. The versatility and the ultra-low-cost solution we presented could ease the daily workflow of researchers in various research fields. Furthermore, it is valuable to high school or undergraduate student labs and community wet labs for science enthusiasts, where funding is generally limited.

Taking a step back from testing: Preanalytical considerations in molecular infectious disease diagnostics

Recent studies evaluating the preanalytical factors that impact the outcome of nucleic-acid based methods for the confirmation of SARS-CoV-2 have illuminated the importance of identifying variables that promoted accurate testing, while using scarce resources efficiently. The majority of laboratory errors occur in the preanalytical phase. While there are many resources identifying and describing mechanisms for main laboratory testing on automated platforms, there are fewer comprehensive resources for understanding important preanalytical and environmental factors that affect accurate molecular diagnostic testing of infectious diseases. This review identifies evidence-based factors that have been documented to impact the outcome of nucleic acid-based molecular techniques for the diagnosis of infectious diseases.

Effects of micropipette handle diameter and inclusion of finger rest on basilar thumb joint contact mechanics

Micropipette users commonly experience problems in the hand and upper limbs. Mechanical factors are thought to contribute to osteoarthritis (OA) initiation and progression in the basilar thumb joint. Finite element analysis can be used to examine the effects of micropipette design on contact mechanics measures within the basilar thumb joint. This pilot study examined the effect of micropipette handle diameter (12 mm, 25 mm, and 40 mm) and the presence of a finger rest on contact area, contact force, and peak contact pressure in the basilar thumb joint. All contact mechanics measures decreased with increasing handle diameter with significant differences between the 12 mm diameter and the 40 mm diameter handles (contact area down about 30 mm², contact force down about 15 N, and peak pressure down about 1 MPa). Decreasing contact mechanics measures with increasing diameter matched our expectations that contact measures would decrease with a more open grip. Contact mechanics measures were higher (p < 0.05) with a finger rest for contact area and force. We expected peak contact pressure and contact area to decrease with the presence of a finger rest. The unexpected outcome may have been due to non-randomized testing order and fatigue during testing.

A Modular MRI-Compatible Pipette Simulator to Evaluate How Design Effects the Basilar Thumb Joint Mechanics

People who frequently use micropipettes experience hand and upper limb disorders. The basilar thumb joint, also known as the first carpometacarpal or trapeziometacarpal joint, is commonly affected by osteoarthritis (OA). Mechanical factors are associated with OA initiation and progression. We developed a MRI-compatible modular micropipette simulator to improve understanding of how micropipette design affects basilar thumb joint contact mechanics. The micropipette simulator also addresses limitations of current techniques for studying pipetting and basilar thumb joint mechanics. Its modularity will allow future studies to examine handle design parameters such as handle diameter, cross-sectional shape, and other features. A micropipette simulator with a cylindrical handle (length 127 mm, diameter 25 mm) was used with one subject to demonstrate the system's feasibility. Contact areas were within the range of prior data from basilar thumb joint models in power grasp and lateral pinch, and contact pressures were the same order of magnitude.

Reducing thumb extensor risk in laboratory rat gavage

Gavage is a common technique for orally administering compounds to small laboratory animals using a syringe. It involves highly repetitive thumb extensor exertions for filling the syringe, a risk factor for DeQuervain's tenosynovitis. As an intervention, a series of bench tests were performed varying fluid viscosity, syringe size and needle size to determine the forces required for drawing fluid. Forces up to 28 N were observed for a viscosity of 0.29 Pa s. A guide is presented to minimize thumb forces for a particular combination of syringe (3 mL, 5 mL and 10 mL), fluid viscosity (0.001 Pa s, 0.065 Pa s, 0.21 and 0.29 Pa s), and needle length (52 mm, 78 mm and 100 mm) based on maximum acceptable exertion levels. In general, a small syringe and large needle size had a greater number of acceptable rat gavages per day due to the lower forces experienced as compared to all other syringe and needle combinations.