Implementation of a Five Degree of Freedom Automated System to Determine Knee Flexibility In Vitro

This article describes an automated system designed to study the complete flexibility functions of the knee in vitro. The system allows five degrees of freedom with flexion angle being fixed, though adjustable from 0 to 45 deg. Loads corresponding to each of the five motions can be applied independently and in any combination. The effect of weight bearing on knee flexibility can also be studied by including axial force as one of the five loads. The relative motions are measured with LVDT’s and RVDT’s, and the loads are measured with strain gage transducers. The system is digitally controlled with a closed feedback loop, allowing for any combination of programmed loads. A control algorithm on an IBM PC/AT monitors the loads on each axis and continuously adjusts stepping motors to correctly follow programmed loads. The machine coordinate system corresponds to clinically accepted definitions of motion yet retains sequence independence for rotations. Results are presented demonstrating the repeatability of using a functional definition of axis placement to align the leg within the machine. Results are also presented demonstrating the utility of the full flexibility functions of the knee, notably in the determination of significant load interactions between anterior/posterior force and internal/external torque, and varus/valgus torque and internal/external torque.

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The analysis of the permeability process of calcium antagonists in developing transdermal forms with a cardiovascular effect

Pharmacia ◽

10.3897/pharmacia.68.e37632 ◽

2021 ◽

Vol 68 (1) ◽

pp. 189-193

Author(s):

Tatyana Shyteyeva ◽

Svitlana Gubar ◽

Nataliia Smielova ◽

Elena Bezchasnyuk ◽

Liana Budanova

Keyword(s):

Calcium Antagonists ◽

Cardiovascular Effect ◽

Amlodipine Besylate ◽

Pharmaceutical Ingredients ◽

Dialysis Method ◽

Definition Of ◽

The Mathematical Model ◽

Qualitative And Quantitative Characteristics

Aim. The aim of the work was to evaluate the possibility of using calcium antagonists, namely, nifedipine and amlodipine besylate, while conducting transdermal delivery, that included the analysis of in vitro permeability process as a primary preformulation stage of pharmaceutical development of a transdermal dosage form, determination of qualitative and quantitative characteristics of a permeability process and the expediency analysis of development of a therapeutic transdermal system (TTS) with a cardiovascular effect. Materials and methods. The active pharmaceutical ingredients (API) of nifedipine and amlodipine besylate. The study has been carried out in vitro by a dialysis method using a modified diffusion device of the Valia-Chien design. Results. Character analysis, description of the mathematical model and definition of the kinetic parameters in the process of permeability of the studied medicinal products (MP) of nifedipine and amlodipine besylate allowed to evaluate their potential for creating TTS as being positive and appropriate. The implemented methodological approaches allow to substantiate the further algorithm for the development of cardiovascular TTS with the mentioned API.

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Autonomous determination of anterior structures in the early Drosophila embryo by the bicoid morphogen

Development ◽

10.1242/dev.109.4.811 ◽

1990 ◽

Vol 109 (4) ◽

pp. 811-820 ◽

Cited By ~ 16

Author(s):

W. Driever ◽

V. Siegel ◽

C. Nusslein-Volhard

Keyword(s):

Drosophila Embryo ◽

Beta Globin ◽

P Transformation ◽

Early Drosophila Embryo ◽

Maternal Effect Genes ◽

Translational Block ◽

Maternal Gene ◽

Anterior Posterior

A small number of maternal effect genes determine anterior-posterior pattern in the Drosophila embryo. Embryos from females mutant for the maternal gene bicoid lack head and thorax. bcd mRNA becomes localized to the anterior tip of the egg during oogenesis and is the source for the morphogen gradient of bcd protein. Here we show that in vitro transcribed bicoid mRNA that has its own leader sequences substituted by the Xenopus beta-globin 5′ untranslated sequences is translated more efficiently than bicoid mRNA with the natural 5′ mRNA leader when tested in vitro and in Drosophila Schneider cells. When injected into bicoid mutant embryos, only the bcd mRNA with the beta-globin leader sequence, substituted for the natural leader, is able to induce anterior development. We used P-transformation to show that sequences in the 5′ leader are neither necessary for localization of the transcript nor for the translational block of the bcd mRNA during oogenesis. For our injection experiments, we used only one of the identified splicing forms of bcd mRNA. The bcd protein species derived from this mRNA is able to induce anterior development at any position along the anterior-posterior axis. Thus bicoid protein can induce development of head and thorax independent of any other specifically localized morphogenetic factor. Our findings further support the notion that the concentration gradient of bcd protein, and not the existence of different forms of bcd protein, is responsible for specifying subregions of the embryo.

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In Vitro Susceptibility of Multi-Drug Resistant Klebsiellapneumoniae Strains Causing Nosocomial Infections to Fosfomycin. A Comparison of Determination Methods

Pathogens ◽

10.3390/pathogens10050512 ◽

2021 ◽

Vol 10 (5) ◽

pp. 512

Author(s):

Beata Mączyńska ◽

Justyna Paleczny ◽

Monika Oleksy-Wawrzyniak ◽

Irena Choroszy-Król ◽

Marzenna Bartoszewicz

Keyword(s):

Klebsiella Pneumoniae ◽

Nosocomial Infections ◽

Reference Method ◽

Multidrug Resistant ◽

Automated System ◽

Diffusion Method ◽

In Vitro Susceptibility ◽

The Phoenix

Introduction: Over the past few decades, Klebsiella pneumoniae strains increased their pathogenicity and antibiotic resistance, thereby becoming a major therapeutic challenge. One of the few available therapeutic options seems to be intravenous fosfomycin. Unfortunately, the determination of sensitivity to fosfomycin performed in hospital laboratories can pose a significant problem. Therefore, the aim of the present research was to evaluate the activity of fosfomycin against clinical, multidrug-resistant Klebsiella pneumoniae strains isolated from nosocomial infections between 2011 and 2020, as well as to evaluate the methods routinely used in hospital laboratories to assess bacterial susceptibility to this antibiotic. Materials and Methods: 43 multidrug-resistant Klebsiella strains isolates from various infections were tested. All the strains had ESBL enzymes, and 20 also showed the presence of carbapenemases. Susceptibility was determined using the diffusion method (E-test) and the automated system (Phoenix), which were compared with the reference method (agar dilution). Results: For the reference method and for the E-test, the percentage of strains sensitive to fosfomycin was 65%. For the Phoenix system, the percentage of susceptible strains was slightly higher and stood at 72%. The percentage of fosfomycin-resistant strains in the Klebsiella carbapenemase-producing group was higher (45% for the reference method and E-test and 40% for the Phoenix method) than in carbapenemase-negative strains (25%, 25%, and 20%, respectively). Full (100%) susceptibility categorical agreement was achieved for the E-test and the reference method. Agreement between the automated Phoenix system and the reference method reached 86%. Conclusions: Fosfomycin appears to be the antibiotic with a potential for use in the treatment of infections with multidrug-resistant Klebsiella strains. Susceptibility to this drug is exhibited by some strains, which are resistant to colistin and carbapenems. The E-test, unlike the Phoenix method, can be an alternative to the reference method in the routine determination of fosfomycin susceptibility, as it shows agreement in terms of sensitivity categories and only slight differences in MIC values. The Phoenix system, in comparison to the reference method, shows large discrepancies in the MIC values and in the susceptibility category.

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Differences in tibiofemoral kinematics between the unloaded robotic passive path and a weightbearing knee simulator

Orthopedic Reviews ◽

10.4081/or.2012.e2 ◽

2012 ◽

Vol 3 (2) ◽

pp. 2 ◽

Cited By ~ 4

Author(s):

Markus Wünschel ◽

Ulf Leichtle ◽

JiaHsuan Lo ◽

Nikolaus Wülker ◽

Otto Müller

Keyword(s):

Knee Joint ◽

Degrees Of Freedom ◽

Weight Bearing ◽

Reaction Force ◽

Joint Kinematics ◽

Vertical Ground Reaction Force ◽

Knee Simulator ◽

6 Degrees Of Freedom ◽

Tibiofemoral Kinematics

Cadaveric in vitro studies are essential to test hypotheses concerning surgical manipulations in the same individual. Robotic technologies as well as different knee-models have been developed to get an in-depth comprehension of knee joint kinematics. The purpose of this study was to compare utilization of these different established principles. Ten human cadaveric knee specimens were used to measure the kinematics during a weight-bearing flexion in a 6-degrees-of-freedom knee simulator. While flexing the knee, joint quadriceps muscle forces were dynamically simulated to reach a vertical ground reaction force of 100N. Fourteen knee specimens were mounted in 6-degrees-of-freedom robotic manipulator with a universal force sensor. The unloaded flexing motion of each specimen was measured by finding positions for each degree of flexion where all forces are minimal (passive path). The kinematic data of the kneesimulator and the robot concerning internal-external rotation, anterior-posterior translation, varus-valgus motion, and medial-lateral translation was examined. For all investigated degrees of freedom the kinematics of the robotic passive path differed from the loaded kinematics in the knee simulator. Simulated bodyweight as well as the examination method used has a substantial influence on joint kinematics during flexion which has to be considered when interpreting biomechanical studies as well as clinical tests.

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Determination of elastic characteristics of cataractously changed lenses in the experiment

Bulletin of Siberian Medicine ◽

10.20538/1682-0363-2008-2-52-55 ◽

2008 ◽

Vol 7 (2) ◽

pp. 52-55

Author(s):

A. A. Kokova

Keyword(s):

Human Eye ◽

Definition Of ◽

Original Device ◽

Elastic Characteristics

The purpose of the investigation is the definition of numeral meanings of the Young’s module on the central part of cataract in vitro. The experiment was carried out by the method of penetration on 108 lenses of a human eye with the help of the developed original device. It is revealed that the area of resilience display is within small limits of unit strain. The Young’s module is within 2 MPa to 6 MPa and depends on the density of a lens nucleus (III—V) according to Buratto.

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