scholarly journals Analysis of the coefficient of variation in shear and tensile bond strength tests

2005 ◽  
Vol 13 (3) ◽  
pp. 243-246 ◽  
Author(s):  
Fábio Lourenço Romano ◽  
Gláucia Maria Bovi Ambrosano ◽  
Maria Beatriz Borges de Araújo Magnani ◽  
Darcy Flávio Nouer
Keyword(s):  
Coefficient Of Variation ◽  
Mean Value ◽  
Scientific Article ◽  
A Value ◽  
Statistical Analysis System ◽  
Strength Tests ◽  
Analysis System ◽  
Very High

The coefficient of variation is a dispersion measurement that does not depend on the unit scales, thus allowing the comparison of experimental results involving different variables. Its calculation is crucial for the adhesive experiments performed in laboratories because both precision and reliability can be verified. The aim of this study was to evaluate and to suggest a classification of the coefficient variation (CV) for in vitro experiments on shear and tensile strengths. The experiments were performed in laboratory by fifty international and national studies on adhesion materials. Statistical data allowing the estimation of the coefficient of variation was gathered from each scientific article since none of them had such a measurement previously calculated. Excel worksheet was used for organizing the data while the sample normality was tested by using Shapiro Wilk tests (alpha = 0.05) and the Statistical Analysis System software (SAS). A mean value of 6.11 (SD = 1.83) for the coefficient of variation was found by the data analysis and the data had a normal distribution (p>0.05). A range classification was proposed for the coefficient of variation from such data, that is, it should be considered low for a value lesser than 2.44; intermediate for a value between 2.44 and 7.94, high for a value between 7.94 and 9.78, and finally, very high for a value greater than 9.78. Such classification can be used as a guide for experiments on adhesion materials, thus making the planning easier as well as revealing precision and validity concerning the data.

scholarly journals Contribuição da inclusão de polpa cítrica e casca de soja para a qualidade da silagem de resíduo úmido de cervejaria

2014 ◽  
Vol 66 (1) ◽  
pp. 277-283
Author(s):  
G.F. Greghi ◽  
B. Barcelos ◽  
A. Saran Netto ◽  
F.G. Vilela ◽  
P.H.M. Rodrigues ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Statistical Analysis System ◽  
Analysis System

Com o objetivo de avaliar a produção da silagem e o uso de aditivos no processo de ensilagem do resíduo úmido de cervejaria, foram realizados 5 tratamentos: controle (C: ensilagem de 100% de resíduo úmido de cervejaria); PC15 (15% de polpa cítrica); PC30 (30% de polpa cítrica); CS15 (15% de casca de soja); CS30 (30% de casca de soja) - com base na matéria fresca do resíduo de cervejaria. As silagens foram confeccionadas em baldes plásticos com 252mm de altura e 245mm de diâmetro (0,06174m³), e amostras foram coletadas para análises bromatológicas, pH, nitrogênio amoniacal, digestão in vitro de matéria seca, ácidos orgânicos e perfil microbiológico. Os resultados foram analisados pelo programa computacional Statistical Analysis System (Statistical..., 1985), sendo verificada a normalidade dos resíduos pelo Teste de Shapiro-Wilk (PROC UNIVARIATE), e as variâncias, pelo Teste de Hartley. Os efeitos dos níveis de adição foram separados por meio de contrastes polinomiais utilizando o nível de significância de 5%. Houve aumento do teor de matéria seca, carboidratos solúveis, ácido lático, digestão in vitro de matéria seca, da população de bactérias ácido láticas e redução do pH, ácido butírico, propiônico e nitrogênio amoniacal a partir das inclusões de polpa cítrica e casca de soja, sendo os melhores resultados encontrados para o tratamento com inclusão de 30% de polpa cítrica (P<0,05). A ensilagem do bagaço de malte por si só é uma alternativa para o produtor rural como suporte alimentar e confecção de silagem de qualidade que pode ser incrementada com o uso de aditivos a serem avaliados de acordo com a relação custo-benefício para eficiência da produção.

Analisa Perbaikan Postur Kerja Dengan Menggunakan Metode OWAS (Ovako Work Analysis System) Dengan Perancangan Fasilitas Di Bagian Penyortiran Batu Gamping PT. Timbul Persada

2019 ◽  
Vol 2 (1) ◽  
pp. 104
Author(s):  
Krishna Tri Sanjaya ◽  
Apreza Dwi Vidyantoro
Keyword(s):  
Work Analysis ◽  
Work Attitude ◽  
Average Value ◽  
Long Period ◽  
A Value ◽  
Work Posture ◽  
Working Posture ◽  
Working Postures ◽  
Analysis System ◽  
Very High

Limestone sorting work at PT. Embossed Persada is a repetitive work attitude and a long period of time, so that it can be at risk of causing Musculoskeletal disorders and discomfort at work. The purpose of this study is to analyze the working posture of limestone sorting operators. There are 3 work postures: limestone sorting work posture has a value of 4141, work posture for limestone removal 2173, and work posture for limestone 3333. Other objectives of this study are to identify work postures that have a risk of Musculoskeletal injury. Based on the results of the categorization of OWAS values, an assessment was obtained: limestone 4141-4 work posture, sludge removal posture 2173-3, work posture inserting limestone 3333-3. The work posture has a very high value where it is necessary to make immediate improvements to the work posture by redesigning the work facilities in the sorting section. Redesign of work facilities carried out to avoid Musculoskeletal interference that is using conveyor aids with a capacity of 9 Tons / Hour. The facility design uses measurements with an average value of Indonesian Ergonomics Anthropometry dataKeyword : Ergonomics, Working Postures, Musculoskeletal, The Design Of The Facility, OWASPekerjaan peyortiran batu gamping di PT. Timbul Persada merupakan sikap kerja yang repetitif dan jangka waktu yang lama, sehingga dapat beresiko menimbulkan gangguan Musculoskeletal dan ketidak nyamanan dalam bekerja. Penelitian ini mencoba untuk mempelajari rangkaian kerja dan aspek Ergonomi yang mempengaruhi postur kerja pada divisi penyortiran tersebut dengan menggunakan metode OWAS (Ovako Work Analysis System), metode ini  digunakan untuk mengevaluasi sikap kerja yang berpotensi mengalami gangguan pada Musculoskeletal dimana postur kerja yang diamati meliputi pergerakan tubuh bagian punggung, bahu, tangan, dan kaki termasuk paha, lutut dan pergelangan kaki. Tujuan dari penelitian ini adalah melakukan analisa postur kerja operator penyortiran batu gamping. Diketahui ada 3 postur kerja : postur kerja pemilahan batu gamping memiliki nilai 4141, postur kerja pengangkatan batu gamping 2173, dan postur kerja memasukan batu gamping 3333. Tujuan lain dari penelitian ini adalah mengidentifikasi postur kerja yang memiliki resiko cedera Musculoskeletal. Berdasarkan hasil pengkategorian nilai OWAS maka, diperoleh penilaian : Postur kerja pemilahan batu gamping 4141-4, postur kerja pengangkatan batu gampng 2173-3, postur kerja memasukkan batu gamping 3333-3. Postur kerja tersebut memiliki nilai yang sangat tinggi dimana perlu dilakukan perbaikan segera terhadap postur kerja dengan perancangan ulang fasilitas kerja pada bagian penyortiran. Perancangan ulang fasilitas kerja yang dilakukan untuk menghindari gangguan Musculoskeletal yaitu menggunakan alat bantu conveyor dengan kapasitas 9 Ton/Jam. Perancangan fasilitas ini dirancang dengan pengukuran menurut nilai rata-rata data Anthropometri Ergonomi Indonesia. Dengan mengevaluasi postur kerja sebelum adanya perbaikan, sehingga hasil dari penelitian ini dapat digunakan sebagai bahan pertimbangan dalam perancangan stasiun kerja yang sesuai dengan aspek-aspek Ergonomi.Kata Kunci : Ergonomi, Postur Kerja, Musculoskeletal, Perancangan Fasilitas, OWAS.

291 EFFECTS OF ANTIOXIDANT AND CULTURE MEDIUM ON THE DEVELOPMENT OF PORCINE IN VITRO-MATURED - IN VITRO-FERTILIZED EMBRYOS

2007 ◽  
Vol 19 (1) ◽  
pp. 261
Author(s):  
C. Choe ◽  
D.-S. Son ◽  
S.-H. Choi ◽  
S.-R. Cho ◽  
H.-J. Kim ◽  
...  
Keyword(s):  
Culture Medium ◽  
Culture Media ◽  
Culture Conditions ◽  
Free Oxygen Radicals ◽  
Blastocyst Formation ◽  
Free Oxygen ◽  
Statistical Analysis System ◽  
Developmental Rates ◽  
Analysis System

Most cells cultured in vitro are exposed to the risk of injury by free oxygen radicals (FOR). However, some of FOR-induced injury could be reduced by the antioxidants and culture medium used for in vitro embryos. This study was undertaken to examine the effects of the antioxidant and culture medium on the development of porcine in vitro-matured–in vitro-fertilized embryos. In Experiment 1, we treated the porcine oocytes in NCSU23 medium with various concentrations of β-mercaptoethanol (β-ME) to determine the effective concentration of antioxidants during IVM of porcine oocytes. In Experiment 2, we tested different culture media to find the proper culture conditions for in vitro porcine embryos. The porcine oocytes that were matured in NCSU23 medium and then fertilized in mTBM medium were cultured in NCSU23 or porcine zygote medium-5. All steps (maturation, fertilization, and development) were carried out in vitro. Differences were analyzed among treatments using the general linear model (GLM) procedure in the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA). The results were summarized as follows. Various concentrations of β-ME showed different developmental rates in porcine embryos. The rates of blastocyst formation at Day 7 after IVF were 9.2 � 1.8 (n = 65), 10.0 � 4.2 (n = 80), 17.5 � 1.1 (n = 63), 20.7 � 1.7 (n = 82), and 14.6 � 1.4 (n = 82) in oocytes treated with β-ME at 0, 10, 25, 50, and 100 �M during IVM, respectively. Of the concentrations of β-ME tested, 50 �M β-ME markedly increased the rates of blastocyst formation at Day 7 (P &lt; 0.05). The rates of blastocyst formation at Day 7 in the NCSU23 and PZM-5 culture media of porcine IVF-derived embryos were 18.8 � 2.6 (n = 96) and 15.6 � 7.1 (n = 77), respectively. The developmental rates were slightly increased in NCSU23, compared with those in PZM-5, but there were no significant differences (P &lt; 0.05) between the NCSU23 and PZM-5 media. In conclusion, these results suggest that the addition of 50 �M β-ME in the IVM medium can improve developmental the rates of porcine embryos in vitro.

305 INCREASED MONOSPERMIC PENETRATION OF PORCINE OOCYTES USING A VISCOUS IN VITRO FERTILIZATION SYSTEM

2007 ◽  
Vol 19 (1) ◽  
pp. 268
Author(s):  
H. Men ◽  
W. Si ◽  
J. K. Critser
Keyword(s):  
Treatment Group ◽  
Gradient Centrifugation ◽  
Sperm Concentration ◽  
Vitro Fertilization ◽  
Statistical Analysis System ◽  
Sperm Penetration ◽  
Discontinuous Percoll Gradient ◽  
Analysis System ◽  
Stock Solutions

The high incidence of polyspermy remains a major problem in porcine IVF systems. The high number of sperm bound to the oocyte is one of the major causes for pathological polyploidy (Funahashi 2003 Reprod. Fertil. Dev. 15, 167–177). In this experiment, we tested the hypothesis that limiting the number of competent sperm able to participate in fertilization during IVF will result in a reduction in polyspermic penetration. Combinations of various sperm (3 levels) and Percoll concentrations (3 levels) were used in a modified Tris-buffered medium (mTBM) with 3% polyvinylpyrrolidone supplementation to find the optimal combination that could result in a significant reduction in polyspermy rate compared with that resulting from the current porcine IVF system (Abeydeera and Day 1997 Theriogenology 48, 537–544). In vitro-matured gilt oocytes (n = 844) were randomly allocated into 1 of 10 treatment groups in groups of 30. Motile sperm were selected from frozen–thawed samples by density gradient centrifugation using a discontinuous Percoll gradient consisting of 3 mL of 54% Percoll in PBS on top of 1 mL of 72% Percoll in a 15-mL conical tube at 600g for 15 min. After centrifugation, the supernatant was removed as much as possible without disturbing the sperm pellet. Sperm stock solutions were made in a manner that resulted in the desired final concentration of sperm when 5 µL of the sperm solution were added to 95 µL of fertilization medium. During IVF, the sperm stock solutions were placed at one side of an IVF droplet so that most sperm were trapped inside the viscous Percoll solution and only a limited number of sperm, with high progressive motility, were capable of fertilizing the oocytes. A group of oocytes fertilized using our standard IVF protocol with a sperm concentration of 5 × 105 sperm mL−1 in mTBM served as a control. Pronuclear formation after 12 h of fertilization was used to assess sperm penetration. The data from 3 replicates were analyzed by standard ANOVA procedures using the Statistical Analysis System (SAS Institute, Inc., Cary, NC, USA). The treatment group of 5 × 105 sperm mL−1 + 10% Percoll resulted in a significantly higher monospermy rate than the control or the treatment group of 1 × 106 sperm mL−1 + 30% Percoll (Table 1; P &lt; 0.05). These data support the hypothesis that the polyspermy rate in a porcine IVF system can be reduced by limiting the number of competent sperm fertilizing the oocytes. Table 1.Monospermy rates in a viscous IVF system (mean ± SEM%) This project was supported by NIH U42 RR 018877.

scholarly journals Some phenomena connected with the transfer of heat by radiation and turbulence in the lower atmosphere

1930 ◽  
Vol 130 (812) ◽  
pp. 98-104 ◽  
Keyword(s):  
Black Body ◽  
Black Body Radiation ◽  
Mean Value ◽  
Absolute Temperature ◽  
Lower Atmosphere ◽  
Lapse Rate ◽  
A Value ◽  
Radiative Diffusion ◽  
The Mean ◽  
Very High

One of the most outstanding facts of observation of the distribution of temperature in the atmosphere is the constancy of the mean lapse-rate of temperature at all heights within the troposphere and in all latitudes. The variation about the mean value, which is roughly one-half of the dry adiabatic lapse-rate, is very slight at all heights greater than a few hundred metres above the ground, but in the layer nearest the ground the extent of the variation is very considerable. At night, and particularly during clear nights in winter, the sign of the lapse-rate in the lowest layer is changed, and the temperature increases with height instead of decreasing. On sunny summer afternoons the lapse-rate in the lowest layers attains very high values, the change of temperature from 1/2 metre to 1 metre above the ground amounting to the equivalent of 100 to 200 times the dry adiabatic lapse-rate. Observations in the layers still nearer to the ground are not yet available, but the nature of the values hitherto observed suggests that the lapse-rate increases in a marked manner as we approach the surface. This raises a very natural question. Is there any limit to the lapse-rate which physically capable of foundation in the atmosphere immediately above the ground? In an earlier paper, I have shown that the outward flux of heat (W-radiation) by radiation can be represented by — k ∂͞T/∂͞z calories/cm. 2 /min., where k is 115/ p m at a temperature of 275° A., p w being the vapour pressure in millibars, and T representing the absolute temperature at a height z above the ground. The average amount of incoming radiation which has to be disposed of is given ( loc. cit .) as 0∙275 calories/cm. 2 /min. This, however, is the average over all latitudes, and over day and night, and is too low a value for our present purposes. We shall adopt instead an amount equal to black body radiation at 280° A. amounting to 0∙509 calories/cm. 2 /min. Of this, an amount 0∙290 calories/cm. 2 /min. leaves the ground as W-radiation. These figures would roughly correspond with afternoon sunshine in the British Isles. If we assume the temperature gradient in the layer near the ground to be ∂͞T/∂͞z, then it has been shown ( loc. cit .) that in this layer the amount of W-radiation transported outward by radiative diffusion is —1/2 k ∂͞T/∂͞z. If the lapse-rate has the value given by the equation.

K transport in upper portion of descending limbs of long-loop nephron from hamster

1987 ◽  
Vol 252 (3) ◽  
pp. F387-F392 ◽  
Author(s):  
K. Tabei ◽  
M. Imai
Keyword(s):  
Potassium Transport ◽  
Flame Photometry ◽  
Passive Permeability ◽  
A Value ◽  
Potassium Flux ◽  
Tubular Lumen ◽  
Net Flux ◽  
K Transport ◽  
Very High

By use of the in vitro microperfusion technique, we investigated potassium transport in the upper portion of the descending limb of the long-loop nephron isolated from hamster kidney. The net potassium flux determined by ultramicro-flame photometry was -0.63 +/- 1.84 pmol X mm-1 X min-1, a value that was not significantly different from zero. The salt permeability for KCl was calculated from the amount of potassium entering the tubular lumen when the concentration of potassium in the bath was increased by approximately 5 mM. The value was 38.9 +/- 1.9 X 10(-5) cm X s-1. The bidirectional fluxes of 86Rb were measured as indices of potassium fluxes. Flux coefficients from lumen-to-bath and bath-to-lumen were 51.2 +/- 9.2 and 48.8 +/- 13.5 X 10(-5) cm X s-1, respectively. These values were not significantly different, confirming that there was no net flux for 86Rb. In another series of five experiments, the lumen-to-bath 86Rb flux coefficients were 69.4 +/- 13.2 X 10(-5) cm X s-1 in the absence of unlabeled Rb, and 70.2 +/- 13.9 X 10(-5) cm X s-1 in the presence of 5 mM unlabeled Rb. The lumen-to-bath 42K flux coefficient measured in the same series of animals was 85.3 +/- 10.5 X 10(-5) cm X s-1 (n = 10), a value that is slightly higher than, but not significantly different from, that of 86Rb. These data show that active potassium transport may exist in this segment and that the passive permeability for potassium is very high.(ABSTRACT TRUNCATED AT 250 WORDS)

Abrasivity of Desensitizing Dentifrice Containing Sodium Metasilicate

2007 ◽  
Vol 330-332 ◽  
pp. 1397-1400
Author(s):  
S.O. Jang ◽  
Su Young Lee ◽  
Hae Sun Kim ◽  
W.G. Chung ◽  
Kyoung Nam Kim ◽  
...  
Keyword(s):  
Surface Profile ◽  
In Vitro Study ◽  
Sodium Metasilicate ◽  
Diamond Wheel ◽  
British Standard Institution ◽  
Statistical Analysis System ◽  
Group 2 ◽  
Analysis System ◽  
Group 1

This in vitro study compared the abrasivity of commercial desensitizing dentifrices with a sodium metasilicate (Na2SiO3) dentifrice using a Surface Profile Method. Dentin specimens were made from the root of extracted human molars. The cervical part of the teeth was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the surface was gradually polished by silicone carbide paper. After grinding, the degree of surface roughness was tested within the range of 2 mm with tapping. The British Standard Institution reference dentifrice (BSI: CaCO3 40%) and experimental dentifrices (group 1: Na2SiO3 25%, CaCO3 10% and SiO2 10%, group 2: CaCO3 10% and SiO2 10%, group 3: CaCO3 10% and SrCl2 10%, group 4: Colloidal Silica 2-3% and Hydroxyapatite 10-20%) were evaluated. The dentifrice slurries were prepared by mixing 24 grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed with the dentifrice slurries 1,000 times. The relative abrasivity of each dentifrice was evaluated from the ratio of the BSI standard dentifrice to each experiment. The results were analyzed by one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical analysis system) 12.0. Groups 1 (71), 2 (74.2), 3 (38) and 4 (7.8) showed a lower abrasivity than the BSI dentifrice (100) (p<0.05). The relative abrasivity of groups 3 (38) and 4 (7.8) was the lowest compared with the BSI dentifrice (100). However, group 1 (71) containing Na2SiO3 showed a similar abrasivity to group 2 (74.2), which did not contain Na2SiO3 (p>0.05). Therefore, Na2SiO3 had no influence on the abrasivity of the dentifrice. In conclusion, the dentifrice containing Na2SiO3 had a lower abrasivity than the BSI reference dentifrice, but showed a significantly higher abrasivity than the existing commercial desensitizing dentifrices. Overall, the relatively high abrasivity of Na2SiO3 dentifrice is believed to be the result of other components in the abrasive system.

Reliability of a Single β-Thromboglobulin Measurement in a Diabetic Population : Importance of PGE1 in Anticoagulant Mixture

1987 ◽  
Vol 57 (02) ◽  
pp. 201-204 ◽  
Author(s):  
P Y Scarabin ◽  
L Strain ◽  
C A Ludlam ◽  
J Jones ◽  
E M Kohner
Keyword(s):  
In Vitro Release ◽  
Mean Value ◽  
Reliable Estimate ◽  
Diabetic Patients ◽  
Single Measurement ◽  
Diabetic Population ◽  
The Difference ◽  
Vitro Release

SummaryDuring the collection of samples for plasma β-thromboglobulin (β-TG) determination, it is well established that artificially high values can be observed due to in-vitro release. To estimate the reliability of a single β-TG measurement, blood samples were collected simultaneously from both arms on two separate occasions in 56 diabetic patients selected for a clinical trial. From each arm, blood was taken into two tubes containing an anticoagulant mixture with (tube A) and without (tube B) PGE!. The overall mean value of B-TG in tube B was 1.14 times higher than in tube A (p <0.01). The markedly large between-arms variation accounted for the most part of within-subject variation in both tubes and was significantly greater in tube B than in tube A. Based on the difference between B-TG values from both arms, the number of subjects with artifically high B-TG values was significantly higher in tube B than in tube A on each occasion (overall rate: 28% and 14% respectively). Estimate of between-occasions variation showed that B-TG levels were relatively stable for each subject between two occasions in each tube. It is concluded that the use of PGEi decreases falsely high B-TG levels, but a single measurement of B-TG does not provide a reliable estimate of the true B-TG value in vivo.

Daunorubicin and Platelet Function

1981 ◽  
Vol 45 (01) ◽  
pp. 038-042 ◽  
Author(s):  
M E Pogliani ◽  
R Fantasia ◽  
G Lambertenghi-Deliliers ◽  
E Cofrancesco
Keyword(s):  
Electron Microscope ◽  
Cellular Membrane ◽  
Hemorrhagic Diathesis ◽  
Clot Retraction ◽  
Freezing And Thawing ◽  
Platelet Factor ◽  
High Doses ◽  
Very High ◽  
Platelet Functions

SummaryThe influence of Daunorubicin on some platelet functions in vitro was investigated, using different concentrations of the drug (0.01-0.02-0.04 μg/ml). Daunorubicin was shown to inhibit Collagen and Thrombin induced platelet aggregation and the intensity of inhibition depended on both drug concentration and the time of preincubation.Daunorubicin was also shown to inhibit the release reaction, the platelet prostaglandin pathway and the availability platelet factor 3; the drug at concentrations for clinical use does not damage the platelet membrane, as is the case with the freezing and thawing test, in platelet uptake of 14C-serotonin and as confirmed by the electron microscope. When very high doses (0.16 mg) of Daunorubicin are used, lysis of the platelets can be observed and this is confirmed under the electron microscope by the presence of empty platelets with fractures at the level of the cytoplasmic membrane.Finally, Daunorubicin causes irreversible inhibition of reptilase clot-retraction, even if this is less severe than with Vincristine. Working with gel-filtered platelets, it would appear that the inhibition exercised by the drug on platelet reactions is not caused through modifications in Ca++ metabolism.The authors suggest that Daunorubicin, at the dosages used clinically, induces in vitro thrombocytopathy without damaging the cellular membrane as confirmed by the electron microscope.This impairment of platelet functions could play a part in hemorrhagic diathesis observed during Daunorubicin therapy.

Effects of Heparin Oligosaccharides with High Affinity for Antithrombin III in Experimental Venous Thrombosis

1982 ◽  
Vol 47 (03) ◽  
pp. 244-248 ◽  
Author(s):  
D P Thomas ◽  
Rosemary E Merton ◽  
T W Barrowcliffe ◽  
L Thunberg ◽  
U Lindahl
Keyword(s):  
Antithrombin Iii ◽  
Specific Activity ◽  
High Specific Activity ◽  
Factor Xa ◽  
Blood Levels ◽  
Thrombin Time ◽  
High Affinity ◽  
Very High

SummaryThe in vitro and in vivo characteristics of two oligosaccharide heparin fragments have been compared to those of unfractionated mucosal heparin. A decasaccharide fragment had essentially no activity by APTT or calcium thrombin time assays in vitro, but possessed very high specific activity by anti-Factor Xa assays. When injected into rabbits at doses of up to 80 ¼g/kg, this fragment was relatively ineffective in impairing stasis thrombosis despite producing high blood levels by anti-Xa assays. A 16-18 monosaccharide fragment had even higher specific activity (almost 2000 iu/mg) by chromogenic substrate anti-Xa assay, with minimal activity by APTT. When injected in vivo, this fragment gave low blood levels by APTT, very high anti-Xa levels, and was more effective in preventing thrombosis than the decasaccharide fragment. However, in comparison with unfractionated heparin, the 16-18 monosaccharide fragment was only partially effective in preventing thrombosis, despite producing much higher blood levels by anti-Xa assays.It is concluded that the high-affinity binding of a heparin fragment to antithrombin III does not by itself impair venous thrombogenesis, and that the anti-Factor Xa activity of heparin is only a partial expression of its therapeutic potential.

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