In Vitro Testing of Elastomeric Modules

1989 ◽  
Vol 16 (4) ◽  
pp. 265-269 ◽  
Author(s):  
P. c. K. Chung ◽  
S. H. Y. Wei ◽  
I. R. Reynolds
Keyword(s):  
Extensive Study ◽  
Applied Force ◽  
In Vitro Testing ◽  
Canine Retraction ◽  
Significant Difference ◽  
Different Types ◽  
Preliminary Study ◽  
Set Up

This study describes the in vitro testing of elastomeric modules. Measurements were first made from study models to establish the clinical distance over which modules are used for canine retraction. From this preliminary study, a typodont, banded with 0·018” × 0·025” standard edgewise brackets, was set up with the canin-molar distance at 28 mm. Modules for canine retraction were then fitted by 11 clinicians. The applied force ranged from 125 to 310 g (221±51 g). A similar, but more extensive study using six different types of modules and two clinician groups (experienced and less experienced clinicians) was then undertaken. Mean force values for different module types ranged from 195±45 g to 318±90 g. There was no statistically significant difference between the force values applied by experienced and less experienced clinicians

scholarly journals Comparative Time-Dependent Evaluation of Dimensional Accuracy of Dies Using Different Tray Adhesives: An In Vitro Study

2018 ◽  
Vol 6 (02/03) ◽  
pp. 106-111
Author(s):  
Ramandeep Kaur ◽  
Manjit Kumar ◽  
Shailesh Jain ◽  
Neha Jindal
Keyword(s):  
Bond Strength ◽  
In Vitro Study ◽  
Dimensional Accuracy ◽  
Time Dependent ◽  
Time Intervals ◽  
Crosshead Speed ◽  
Significant Difference ◽  
Different Types ◽  
Separation Failure

Abstract Statement of Problem The adhesion of impression material to impression tray is very important. Tray adhesive plays a major role in making accurate impression. Although manufactures recommend the use of particular tray adhesives, comparison of their affective adhesiveness has not been reported. The effect of use of tray adhesives on dimensional accuracy of dies has not been established. Purpose The aim of this study was to compare the dimensional accuracy of dies using different tray adhesives at different time intervals. Materials and Methods First part of study comprised 120 samples in six groups with 20 samples in each group. First group comprised samples with no tray adhesive, and in other five groups, different types of tray adhesives were applied. The dies obtained were evaluated for upper diameter, lower diameter, and occlusogingival height. In the second part, there were a total of 125 samples in five groups with 25 samples in each group. Five different types of tray adhesive were applied for five different time intervals 5, 10, 15, 20, and 25 minutes, respectively. The specimens were tested in tensile mode for its debonding force at a crosshead speed of 5 mm/min, until separation failure occurred. Results Significant difference was seen for upper and lower diameters when compared with the group without any tray adhesive. The maximum bond strength was found in the group in which tray adhesive was applied for 20 minutes.

52 INITIATION OF PREGNANCIES IN SOUTH AFRICAN RIVERINE RABBIT (BUNOLAGUS MONTICULARES) BY INTERSPECIES NUCLEAR TRANSFER USING ADIPOSE-DERIVED SOMATIC CELLS

2008 ◽  
Vol 20 (1) ◽  
pp. 106
Author(s):  
M. J. Sansinena ◽  
D. Owiny ◽  
R. S. Denniston ◽  
D. Salamone ◽  
D. Barry
Keyword(s):  
In Vitro Culture ◽  
Nuclear Transfer ◽  
Uv Light ◽  
Uv Exposure ◽  
Domestic Rabbit ◽  
Donor Cells ◽  
Significant Difference ◽  
Preliminary Study ◽  
Interspecies Nuclear Transfer

The riverine rabbit (Bunolagus monticulares), one of South Africa's most threatened mammals, with an estimated population size under 250, was upgraded from endangered to critically endangered in 2002. The low number of riverine rabbits precludes any attempts of nuclear transfer (NT) using intraspecific oocytes; therefore, the overall aim of this study was to assess the ability of the domestic rabbit (Oryctolagus cuniculus) oocyte to reprogram the somatic cell of the endangered riverine rabbit by interspecies NT. A preliminary study evaluated the effect of timing of enucleation after induction of ovulation (h post-hCG). A second study assessed the effects of two activation protocols. In addition, since the unique characteristics of the rabbit zona pellucida affect the speed of micromanipulation, different exposure periods to UV light at enucleation were evaluated. Adult domestic Californian rabbits were treated with eCG for 72 h, and ovulation was induced by hCG administration. Oocytes were collected by retrograde flushing at 12–14 h or 16–18 h post-hCG administration and stripped of cumulus investments with 0.5% hyaluronidase in Ca-Mg-free PBS. Metaphase-II oocytes were selected by visualizing the first polar body. Oocytes were stained with 2 mg mL–1 Hoechst 33342 for 5 min, and metaphase plates were removed with a 25–30 μm (O.D.) borosilicate beveled, spiked pipette after exposure to <5 or 30–40 s of UV light. Adult adipose-derived riverine rabbit fibroblasts grown to confluency in DMEM with 10% FCS were used as donor cells and fused with 2 consecutive DC pulses (3.2 kV cm–1, 45 μs). After reconstruction, couplets were randomly assigned for activation by either a second set of electrical pulses or incubation with ionomycin, followed by 1 h of incubation in 2 mm 6-DMAP. Embryos were co-cultured with a bovine oviductal cell monolayer in DMEM with 10% FCS and assessed for cleavage after 36 h of in vitro culture. There was a significant difference in the number of cleaved embryos from oocytes collected at 12–14 h post-hCG (n = 50) or 16–18 h post-hCG (n = 51) administration (57% v. 0% cleaved; P < 0.05). No significant difference was detected in embryos developing after electrofusion v. ionomycin activation treatments. However, a significantly greater number (P < 0.05) of embryos cleaved from oocytes exposed to <5 s UV than from oocytes exposed to 30–40 s UV (Table 1). A total of 20 embryos (4-cell to 16-cell stages) were surgically transferred to the oviducts of 4 adult New Zealand white synchronized recipients after 48 h of in vitro culture. Two recipients (<5 s UV exposure treatment group) were diagnosed pregnant by abdominal palpation at 15 days post-transfer; pregnancies were subsequently lost by Day 30, with placental tissues recovered. This preliminary study indicates the domestic rabbit oocyte is capable of reprogramming riverine rabbit donor cells. In addition, the time of oocyte collection after ovulation induction and the UV exposure period during enucleation have an effect on the efficiency of interspecies NT and embryo development in this species. Table 1. Effect of UV exposure during enucleation on the in vitro development of interspecies nuclear transfer riverine rabbit embryos

scholarly journals Pengaruh perbedaan jenis pakan terhadap pertumbuhan lobster laut, Panulirus versicolor

2017 ◽  
Vol 5 (3) ◽  
Author(s):  
Lestari Makasangkil ◽  
Indra R.N. Salindeho ◽  
Cyska Lumenta
Keyword(s):  
Body Weight ◽  
The Body ◽  
Regression Coefficients ◽  
Body Weight Change ◽  
Fish Flesh ◽  
Quality Degradation ◽  
Significant Difference ◽  
Different Types ◽  
Set Up ◽  
Test Level

The aim of the research was to find out the growth rate of the marine lobster, Panulirus versicolor, fed different types of diets.   The experiment was conducted at the Laboratory of Aquaculture Technology, Faculty of Fisheries and Marine Sciences, Sam Ratulangi University.  The experiment was set up  in 3 treatments, which were three different types of diet: treatment-A: papaya leaves, treatment-B: coconut flesh, treatment-C: skipjack-fish flesh.  Each treatment was triplicated.  The tested lobsters were collected from the marine waters of the Likupang village, North Minahasa Regency.  The tested lobsters were weighed at the beginning,  at the end of the experiment, and at the interval of 14 days during the experiment period. The data of the body weight change were statistically analysed using the analysis of the homogeneity of the 3 different linear regression coefficients, between time (X) and the body weight of the lobsters (Y) fed different types of feed, at the confidence test level a = 5% and 1%.  The results show that the body weight of the tested lobsters fed skipjack-fish flesh increased 4 grams after 30 days of the rearing period.  The body weight of the tested lobsters fed papaya leaves decreased 11 g, and the body weight of those fed coconut flesh decreased 3 g after 30 days of the rearing period.  The result of the regression analysis shows, the assumption that the 3 regression coefficients are homogenous is rejected.  In other words, there is a significant difference among the growth rates of the tested lobsters fed different type of diets.  Compared to skipjack-fish flesh, the papaya leaves and coconut flesh significantly slow down the level of the water quality degradation during experiment period.Keywords:  diets, growth, marine-lobster

scholarly journals A PRELIMINARY STUDY OF THE EFFECT OF ANESTHETIC AGENTS ON THE RHEOLOGICAL PARAMETERS OF GLYCATED ERYTHROCYTES

Anales AFA ◽  
2021 ◽  
Vol 31 (4) ◽  
pp. 117-120
Author(s):  
M. V. Batista da Silva ◽  
◽  
H. Castellini ◽  
N. A. Alet ◽  
B. Riquelme ◽  
...  
Keyword(s):  
Membrane Surface ◽  
Vecuronium Bromide ◽  
Rheological Parameters ◽  
Diabetic Patients ◽  
Anesthetic Agents ◽  
Aggregation Kinetic ◽  
Different Types ◽  
Preliminary Study ◽  
Aggregation Parameters

This paper presents a preliminary study of the effects of the anesthetics propofol, remifentanil, and vecuronium bromide on the rheological properties of glycated erythrocytes in vitro, modeling the glycation by hyperglycemia observed in diabetes. Viscoelastic and aggregation kinetic parameters of erythrocytes were determined using an erythrocyte rheometer and an optical chip aggregometer developed in our laboratory. The results showed significant alterations in the membrane surface viscosity, the elastic modulus, and the erythrocyte deformability index for the different anesthetics studied. Also, the kinetics aggregation parameters showed different types of alterations due to the effect of anesthetics. This preliminary study suggests that the use of these anesthetics in diabetic patients could induce hemorheological alterations that disturb the microcirculation. For this reason, it is recommended to deepen these investigations to prevent complications in surgical procedures.

A modified semi-automated technique for in vitro assessment of encrustation of materials

1997 ◽  
Vol 211 (6) ◽  
pp. 475-478 ◽  
Author(s):  
S Gepi-Attee ◽  
R C L Feneley
Keyword(s):  
In Vitro Study ◽  
Reaction Chamber ◽  
Scanning Electron Micrography ◽  
In Vitro Assessment ◽  
Preliminary Study ◽  
Infected Urine ◽  
Automated Technique ◽  
Set Up ◽  
Edx Microanalysis

In vitro study of encrustation is an important part of assessment of materials as potential alloplasts or devices in the urinary tract. This modified semi-automated technique comprises a circular reaction chamber with an encrustation mixture, the level of which is controlled by a float switch which operates the exit peristaltic pump. The composition of the reactants used simulates infected urine with alkaline pH. Results of a preliminary study of the deposits by scanning electron micrography (SEM) and energy dispersive X-ray (EDX) microanalysis are consistent with struvite and hydroxyapatite, similar to the main minerals deposited on urinary catheters. It is a relatively simple, effective and inexpensive set-up for study of encrustation on materials.

In vitro testing of ciprofloxacin formulations and preliminary study on BCS biowaiver

2020 ◽  
Vol 17 (2) ◽  
Author(s):  
S.B. Kyriacos ◽  
C. Boukarim ◽  
W. Safi ◽  
M. Mroueh ◽  
A.B. Maroun ◽  
...  
Keyword(s):  
In Vitro Testing ◽  
Preliminary Study

scholarly journals In Vitro Comparative Evaluation of Different Types of Impression Trays and Impression Materials on the Accuracy of Open Tray Implant Impressions: A Pilot Study

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Sonam Gupta ◽  
Aparna Ichalangod Narayan ◽  
Dhanasekar Balakrishnan
Keyword(s):  
Reference Model ◽  
Coordinate Measuring Machine ◽  
Dimensional Accuracy ◽  
Impression Material ◽  
Impression Materials ◽  
Significant Difference ◽  
Different Types ◽  
Measuring Machine ◽  
The Difference

Purpose. For a precise fit of multiple implant framework, having an accurate definitive cast is imperative. The present study evaluated dimensional accuracy of master casts obtained using different impression trays and materials with open tray impression technique.Materials and Methods. A machined aluminum reference model with four parallel implant analogues was fabricated. Forty implant level impressions were made. Eight groups (n=5) were tested using impression materials (polyether and vinylsiloxanether) and four types of impression trays, two being custom (self-cure acrylic and light cure acrylic) and two being stock (plastic and metal). The interimplant distances were measured on master casts using a coordinate measuring machine. The collected data was compared with a standard reference model and was statistically analyzed using two-way ANOVA.Results. Statistically significant difference (p<0.05) was found between the two impression materials. However, the difference seen was small (36 μm) irrespective of the tray type used. No significant difference (p>0.05) was observed between varied stock and custom trays.Conclusions. The polyether impression material proved to be more accurate than vinylsiloxanether impression material. The rigid nonperforated stock trays, both plastic and metal, could be an alternative for custom trays for multi-implant impressions when used with medium viscosity impression materials.

Differential responses of rat alveolar macrophages to carpet dust in vitro

2003 ◽  
Vol 22 (5) ◽  
pp. 263-270 ◽  
Author(s):  
Mohamed Ameen ◽  
Iqbal Ahmad ◽  
Syed Musthapa ◽  
Masroor Alam Baig ◽  
Rinky Mishra ◽  
...  
Keyword(s):  
Cell Viability ◽  
Alveolar Macrophages ◽  
Reduced Glutathione ◽  
Epidemiological Studies ◽  
Dust Concentration ◽  
Hemolytic Assay ◽  
Different Types ◽  
Preliminary Study ◽  
Toxic Potential

Epidemiological studies of workers in carpet weaving units in carpet industries have shown a direct relation between the concentration of carpet dust in the air and respiratory symptoms. To predict the health risk of carpet weavers, this preliminary study was conducted to evaluate the toxic potential of different types of workplace dust by using alveolar macrophages (AMs). Several parameters were observed for cytotoxicity such as cell viability, the release of lactate dehydrogenase (LDH) in rat AMs treated with different concentration of carpet dust and haemolytic potential of erythrocytes. In addition, reactive oxygen/nitrogen species-inducing effects of carpet dust were assessed by nitric oxide (NO), reduced glutathione (GSH) release and hydrogen peroxide (H2O2) generation in AMs. Results of cell viability and hemolytic assay showed a direct correlation between increasing the dust concentration with enhancing the toxic effect. Knotted and tufted carpet dust increases the release of LDH, NO, GSH and H2O2 production with increasing dust concentration. Present observations have revealed that dusts collected from tufted carpet weaving units exhibited more toxicity to AMs than knotted carpet dust. These data further suggest that injurious effects of carpet dust to AMs could pave a way to evaluate the toxic potential of the different types of workplace dusts and component(s) involved in it.

scholarly journals The Effects of 1-Beta-D-Arabinofuranosylcytosine and Adriamycin on the Chromosomes of Cultured Human Lymphocytes

2021 ◽  
Author(s):  
◽  
Keith Lyle McLea
Keyword(s):  
Chromosome Aberrations ◽  
Treatment Time ◽  
Unit Length ◽  
Human Lymphocytes ◽  
Sister Chromatid Exchanges ◽  
Significant Difference ◽  
Different Types ◽  
Pass Through ◽  
Chromatid Aberrations

<p>A study of chromosome aberrations induced by 1-Beta-D-arabinofuranosylcytosine (Ara C) and Adriamycin (AM) in the chromosomes of cultured human lymphocytes was made. There were significant increases in the frequency of aberrations with increasing concentrations of both Ara C (2.5, 5.0 and 10.0 mug/ml) and AM (0.01, 0.05, 0.10 and 0.15 mug/ml). The frequency of aberrations induced by both drugs also showed a 'levelling off' above particular concentrations. For Ara C the effect of increasing treatment time was also studied. The frequency of aberrations increased significantly with increasing treatment times (2, 3 and 4 hrs) although no 'levelling off' in the number of aberrations was observed. The relationship between the frequency of the different types of aberrations induced by Ara C and AM was studied. AM allowed for a study of the relative frequency of chromosome versus chromatid aberrations and fragment versus exchange aberrations. There were always more fragments than exchanges, and always more chromatid aberrations than chromosome aberrations. Aberrations induced by Ara C were all of the chromatid fragment type. A study was made of the distribution of inter- and intra-chromosomal aberrations in relation to light and dark G banded chromosomes. Both drugs induced more aberrations in the light G bands than the dark G bands. Both drugs showed distinct clustering of aberrations in some regions of the chromosomes (hotspots), although the location of AM induced hotspots was different from the location of those induced by Ara C. The distribution of AM induced chromatid aberrations was different from the distribution of the chromosome aberrations, as were the distributions of the fragment and exchange aberrations. The different types of aberrations also differed in the number of AM induced aberrations per unit length between the p and q arms. There were more aberrations per unit length in the p arm than in the q arm for exchanges, whereas for fragments and chromosome aberrations the reverse was true. For chromatid aberrations, there was no significant difference in the number of aberrations per unit length between the p and q arms. Inter-individual differences in the frequency of AM induced aberrations were observed in the .AM dosage experiments. Also there was a suggestion that the distribution of Ara C induced aberrations was different for different donors. AM increased the frequency of sister chromatid exchanges. Comparable results were not sought for Ara C because after cells were exposed to Ara C they did not pass through an S phase of the cell cycle, as is the case for cells exposed to AM. The relevance of the present in vitro studies to cancer chemotherapy is briefly discussed.</p>

scholarly journals The Effect of Two Different Polishing Techniques on Microleakage of New Composites in Class V Restorations

2006 ◽  
Vol 7 (5) ◽  
pp. 18-25 ◽  
Author(s):  
Meserret Baseren ◽  
Filiz Yalcin ◽  
Yonca Korkmaz
Keyword(s):  
Composite Resin ◽  
Class V ◽  
Significant Difference ◽  
Different Types ◽  
Nanohybrid Composite ◽  
Group 3 ◽  
Group 2 ◽  
Silicon Based ◽  
Group 1

Abstract Aim The purpose of this study was to investigate the effect of polishing systems on the microleakage of a nanofill, a nanohybrid, and a microhybrid composite in Class V cavities. Methods and Materials Preparations were made at the cemento-enamel junction (CEJ) of 36 extracted human premolars. The teeth were randomly divided into three groups and restored with new resin composites according to the manufacturers’ instructions as follows: Group 1, Filtek Supreme & Single Bond; Group 2, Grandio & Solobond; and Group 3, Artemis & Excite. The restorations were finished with diamond finishing burs. The restored/finished teeth were randomly divided into two groups and polished using the following systems: Super-Snap (Al2O2 coated, abrasive disc system, fine grit, and extra fine grit) and Astropol/Astrobrush (silicon-based abrasive polisher point and polisher brush). All specimens were thermocycled 1000 times with a 10 second dwell time. They were immersed in 0.5% aqueous basic fuchsin dye for 24 hours and then sectioned buccal-lingual-longitudinally through the center of both restorations of each tooth and evaluated under a stereomicroscope at 30X magnification. The degree of dye penetration was quantified. Result No significant difference in leakage scores was observed in enamel margins (p=0.456, Kruskall Wallis test), but dentin margins were significantly affected by the different polishing systems (p=0.037, Kruskall Wallis test). The lower leakage scores were recorded for Astropol/Astrobrush polishing systems. The nanofill composite showed the least leakage among the test groups in this study. The most leakage was observed in nanohybrid composite resin (p<0.05, Mann Whitney U test). Conclusions Under the conditions of this in vitro study: the microleakage resistance of composites at enamel margins is not significantly affected by the different polishing systems; the lowest leakage scores were recorded for Astropol/Astrobrush polishing techniques in different types of composites; and the ranking of the composite materials from most to least leakage at the dentin margins according to polishing techniques was Grandio >Artemis > Filtek Supreme. Citation Yalcin F, Korkmaz Y, BasŞeren M. The Effect of Two Different Polishing Techniques on Microleakage of New Composites in Class V Restorations. J Contemp Dent Pract 2006 November;(7)5:018-025.

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