scholarly journals Continuous Flow Labeling and In-Line Magnetic Separation of Cells

2021 ◽  
Vol 8 (1) ◽  
pp. 5
Author(s):  
Zhixi Qian ◽  
Thomas R. Hanley ◽  
Lisa M. Reece ◽  
James F. Leary ◽  
Eugene D. Boland ◽  
...  
Keyword(s):  
Cell Model ◽  
Point Of Care ◽  
Magnetic Bead ◽  
Cell Labeling ◽  
Diagnostic Systems ◽  
Element Analysis ◽  
Trap Design ◽  
Circulating Cells ◽  
Interfacial Surface ◽  
Generator Type

There is an identified need for point-of-care diagnostic systems for detecting and counting specific rare types of circulating cells in blood. By adequately labeling such cells with immunomagnetic beads and quantum dots, they can be efficiently collected magnetically for quantification using fluorescence methods. Automation of this process requires adequate mixing of the labeling materials with blood samples. A static mixing device can be employed to improve cell labeling efficiency and eliminate error-prone laboratory operations. Computational fluid dynamics (CFD) were utilized to simulate the flow of a labeling-materials/blood mixture through a 20-stage in-line static mixer of the interfacial-surface-generator type. Optimal fluid mixing conditions were identified and tested in a magnetic bead/tumor cell model, and it was found that labeled cells could be produced at 1.0 mL/min flow rate and fed directly into an in-line magnetic trap. The trap design consists of a dual flow channel with three bends and a permanent magnet positioned at the outer curve of each bend. The capture of labeled cells in the device was simulated using CFD, finite-element analysis and magnetophoretic mobility distributions of labeled cells. Testing with cultured CRL14777 human melanoma cells labeled with anti-CD146 1.5 μm diameter beads indicated that 90 ± 10% are captured at the first stage, and these cells can be captured when present in whole blood. Both in-line devices were demonstrated to function separately and together as predicted.

scholarly journals Aptamer-Based Diagnostic Systems for the Rapid Screening of TB at the Point-of-Care

Diagnostics ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1352
Author(s):  
Darius Riziki Martin ◽  
Nicole Remaliah Sibuyi ◽  
Phumuzile Dube ◽  
Adewale Oluwaseun Fadaka ◽  
Ruben Cloete ◽  
...  
Keyword(s):  
Low Income ◽  
Point Of Care ◽  
Health Care Systems ◽  
Cost Effective ◽  
Rapid Screening ◽  
Low Income Countries ◽  
Sputum Smear ◽  
Diagnostic Systems ◽  
Molecular Tests ◽  
Rapid Tests

The transmission of Tuberculosis (TB) is very rapid and the burden it places on health care systems is felt globally. The effective management and prevention of this disease requires that it is detected early. Current TB diagnostic approaches, such as the culture, sputum smear, skin tuberculin, and molecular tests are time-consuming, and some are unaffordable for low-income countries. Rapid tests for disease biomarker detection are mostly based on immunological assays that use antibodies which are costly to produce, have low sensitivity and stability. Aptamers can replace antibodies in these diagnostic tests for the development of new rapid tests that are more cost effective; more stable at high temperatures and therefore have a better shelf life; do not have batch-to-batch variations, and thus more consistently bind to a specific target with similar or higher specificity and selectivity and are therefore more reliable. Advancements in TB research, in particular the application of proteomics to identify TB specific biomarkers, led to the identification of a number of biomarker proteins, that can be used to develop aptamer-based diagnostic assays able to screen individuals at the point-of-care (POC) more efficiently in resource-limited settings.

scholarly journals Using a dual antibody point-of-care test with visual and digital reads to diagnose syphilis among people living with HIV in Botswana

2021 ◽  
pp. 095646242097563
Author(s):  
Irfaan Maan ◽  
David S Lawrence ◽  
Nametso Tlhako ◽  
Kehumile Ramontshonyana ◽  
Aamirah Mussa ◽  
...  
Keyword(s):  
Day Treatment ◽  
Point Of Care ◽  
Kappa Statistic ◽  
People Living With Hiv ◽  
Diagnostic Systems ◽  
Hiv Viral Load ◽  
Past Infection ◽  
Middle Income ◽  
Visual Reading ◽  
Active Syphilis

Syphilis data from low- and middle-income countries are lacking due to limited testing. Point-of-care tests (POCTs) have been promoted to expand testing but previously only included treponemal tests, which cannot distinguish active from past infection. We aimed to assess the feasibility of using a combined treponemal and non-treponemal POCT in HIV clinic patients in Gaborone, Botswana, and estimate syphilis prevalence in our clinic sample using this approach. We recruited 390 non-pregnant patients. Participants underwent a combined treponemal and non-treponemal POCT (Dual Path Platform (DPP®) Syphilis Screen and Confirm Assay (Chembio Diagnostic Systems)) on finger-prick blood sample and a questionnaire. Median age 45 years, 30% men, median CD4 count 565 cells/μL, and 91% had an HIV viral load <400 copies/mL. Five participants had active syphilis (1.3%, 95% CI 0.5–3.0%) and 64 had previous syphilis (16.4%, 95% CI 13.0–20.4%) using the DPP POCT. There was a reasonable level of agreement between digital and visual reading of the POCT (kappa statistic of 0.81); however, visual reading missed three active infections (60%). The level of active syphilis was similar to local antenatal data. The DPP POCT led to five participants with active syphilis being diagnosed and starting same-day treatment. The digital reader should be used.

A FINITE ELEMENT ANALYSIS OF EFFECTIVE THERMOELECTROELASTIC PROPERTIES OF COMPOSITES WITH A DOUBLY PERIODIC ARRAY OF PIEZOELECTRIC FIBERS

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1689-1694 ◽  
Author(s):  
PENG YAN ◽  
CHIPING JIANG
Keyword(s):  
Finite Element ◽  
Effective Properties ◽  
Cell Model ◽  
Periodic Array ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Uniform Temperature Field ◽  
Periodic Microstructures ◽  
Doubly Periodic Array ◽  
Electrical Loads

This work deals with modeling of 1-3 thermoelectroelastic composites with a doubly periodic array of piezoelectric fibers under arbitrary combination of mechanical, electrical loads and a uniform temperature field. The finite element method (FEM) based on a unit cell model is extended to take into account the thermoelectroelastic effect. The FE predictions of effective properties for several typical periodic microstructures are presented, and their influences on effective properties are discussed. A comparison with the Mori-Tanaka method is made to estimate the application scope of micromechanics. The study is useful for the design and assessment of composites.

Point-of-Care Diagnostic Systems

2020 ◽  
pp. 211-274
Author(s):  
Stephanus Büttgenbach ◽  
Iordania Constantinou ◽  
Andreas Dietzel ◽  
Monika Leester-Schädel
Keyword(s):  
Point Of Care ◽  
Diagnostic Systems

scholarly journals Compressive Creep Measurements of Fired Magnesia Bricks at Elevated Temperatures Including Creep Law Parameter Identification and Evaluation by Finite Element Analysis

Ceramics ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 210-222 ◽  
Author(s):  
Guenter Unterreiter ◽  
Daniel R. Kreuzer ◽  
Bernd Lorenzoni ◽  
Hans U. Marschall ◽  
Christoph Wagner ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Creep Behavior ◽  
Elevated Temperatures ◽  
Cell Model ◽  
Experimental Investigations ◽  
Load Range ◽  
Element Analysis ◽  
Compressive Creep ◽  
Creep Deformations

Creep behavior is very important for the selection of refractory materials. This paper presents a methodology to measure the compressive creep behavior of fired magnesia materials at elevated temperatures. The measurements were carried out at 1150–1500 °C and under compression loads from 1–8 MPa. Creep strain was calculated from the measured total strain data. The obtained creep deformations of the experimental investigations were subjected to detailed analysis to identify the Norton-Bailey creep law parameters. The modulus of elasticity was determined in advance to simplify the inverse estimation process for finding the Norton-Bailey creep parameters. In the next step; an extended material model including creep was used in a finite element analysis (FEA) and the creep testing procedure was reproduced numerically. Within the investigated temperature and load range; the creep deformations calculated by FEA demonstrated a good agreement with the results of the experimental investigations. Finally; a finite element unit cell model of a quarter brick representing a section of the lining of a ferrochrome (FeCr) electric arc furnace (direct current) was used to assess the thermo-mechanical stresses and strains including creep during a heat-up procedure. The implementation of the creep behavior into the design process led to an improved prediction of strains and stresses.

Effect of Compressive and Shear Deformation of 2.5D Preform on its Stiffness of Composites

2019 ◽  
Vol 943 ◽  
pp. 75-80
Author(s):  
Fang Bin Lin ◽  
Ying Dai ◽  
Han Yang Li ◽  
Yang Qu ◽  
Wen Xiao Li
Keyword(s):  
Finite Element ◽  
Shear Deformation ◽  
Cell Model ◽  
Deformation Mode ◽  
Element Model ◽  
Tensile Tests ◽  
Woven Composites ◽  
Forming Process ◽  
Element Analysis ◽  
Plane Shear

Transverse compaction and in-plane shear deformartion are the dominative deformation mode for woven preform during forming process. A full finite element model of the 2.5D woven composites has been established by the computed tomography (CT) in this paper. Based on the energy method, the effective orthotropic/anisotropic stiffness coefficientsCijare calculated by performing a finite element analysis (FEA) of this full cell model. Using this model, the effects of the compaction and shear deformation of the 2.5D woven preform on the composites stiffness are investigated in detail. Compared the results of the static tensile tests, the rationality of the model and the method is verified.

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