Indirect Evaluation Methods Research Articles

The Clinical Evaluation of Heat-Treated Composite Resin Inlays

Laboratory research indicates the physical properties of composite resin used for posterior restorations can be significantly increased if a secondary dry heat treatment of the material was accomplished. This study investigated the clinical performance of a heat-treated composite resin inlay, using both the direct and indirect methods of clinical evaluation. Contrary to laboratory results, no significant differences in wear could be measured between conventional light-cured inlays and those with secondary dry heat treatment. Other clinical advantages of the heat-treated inlays were observed.

Three-year clinical evaluation of a self-cured posterior composite resin

A study was conducted to determine whether the wear resistance of a posterior composite could be improved by maximizing filler particle-to-particle contacts. This was expected to reduce stress concentrations on the resin matrix and thus reduce occlusal wear. A self-curing quartz-filled composite with this design, P-10, was used to restore 90 Class I and II cavity preparations in adult teeth. Restorations were recalled after baseline at six months, one year, two years, and three years to measure wear by direct and indirect evaluation methods. There was no apparent advantage for this material compared with other previously evaluated posterior composites. The average cumulative wear for P-10 after three years was 145 μm. In addition, the restorations were evaluated for color-matching, interfacial staining, secondary caries, marginal adaptation, surface texture, and post-operative sensitivity. This material was not significantly different in those ways from other posterior composite products except in terms of more rapid color change, because it is self-cured.

The determination of the microstructure of green coffee by acoustic microscopy

A ‘multiparameter’ method for indirect evaluation of intrinsic anisotropy values for prestressed engineering materials is discussed. The proposed method is based on simultaneous measurement of both the velocity of elastic waves and the parameters, characterizing the frequency dispersion and/or attenuation. Preliminary experimental demonstrations of the feasibility of such methods for common engineering materials are presented.

Production and properties of polyacenaphthylene VII. Unperturbed dimensions and chain conformational studies of polyacenaphthylene

The unperturbed dimensions of polyacenaphthylene in solution were determined from light scattering, osmotic and viscometric data in thermodynamically good solvents and in the theta solvent, 1,2-dichloroethane, using direct and indirect evaluation methods. The estimated value of the steric factor, α, shows polyacenaphthylene to be a relatively rigid polymer in contrast to the results obtained from hydrodynamic investigations. An attempt was made to explain this discrepancy in terms of a tightly coiled conformation is solution due to weak links in the polymer chain.

Evaluation of the cross-sectional areas of the maxillary sinus

Cross-sectional areas of the maxillary sinus were evaluated by frontal section films using Polytome U. A frontal section of 3cm from Nasion was used. Two methods were adopted for the cross-sectional evaluations of the maxillary sinus areas. The direct method is to plot the area over semitransparent section paper divided into squares of which the unit area is 1mm2. The plotted area was directly calculated by the section paper. The indirect method is to use an approximated cross-sectional configuration of the maxillary sinus. The approximation was done by regarding the cross-sectional area as an trapezoid made of lines drawn by orbital floor, lateral wall of the inferior meatus, and the zygomatic recess, and so far. Sixty adults (male 35 and female 25) were included in the study. Majority of the cases were afflicted with chronic sinusitis and no bony destruction was noted.The results were analyzed as to the difference between the sides and gender, and the linear correlation between two methods of evaluation for the cross-sectional areas. Statistically no significant difference was seen between the right and left sides. The results for male were larger than those of female with statistical significance. The linear correlation between the direct and indirect methods is very high.The indirect method of evaluation for the cross-sectional area of the maxillary sinus is thus applicable to the evaluation of the postoperative changes of the maxillary sinus.

Evaluation en prevention primaire: Un must, II, le point de vue pedopsychiatrique

The evaluation of any antenatal prevention program of child abuse and neglect is limited for statistical and ethical reasons, as shown in the first part of the present study (cf., The obstetrical viewpoint by G. Soumenkoff). The authors propose a child psychiatry model of evaluation. Use of the model is illustrated by a 4-year survey of 374 selected high-risk pregnant women followed in the antenatal out-patient department of St. Pieters Hospital in Brussels. A child psychiatrist worked together with several gynecologists, supporting the high-risk couples as well as their children. Several indirect evaluation methods of the quality of screening and the efficiency of the work are analyzed. Long-term evaluation of the children is an absolute necessity. In order to evaluate this type of approach, a simple questionnaire concerning the quality of life of the children under study was derived from a model used in pediatric oncology by the EORTC and adapted to the problems of abused children. One part was answered by the parents which allowed the researchers to evaluate their perception of the child. The second part was filled out by the sociomedical professionals who followed the child. The combination of these two views is rich in information concerning the patient as well as the parents' attitude toward their child.

Biomechanics of fruits and vegetables

The scope of fruit and vegetable biomechanics is reviewed. Sources of mechanical injury to produce in harvesting, processing, storage, packaging and transportation are briefly described. A survey of produce handling and transportation environments was conducted, whereby an envelope model encompassing composite spectra of trucks, railroad, marine and cargo aircraft is presented. The protective quality, i.e. strength of shipping containers is quantified in static and dynamic loading such as encountered in storage, handling and transportation. Mechanical response of fruits and vegetables in quasistatic and dynamic loading are formulated by a nonlinear rheological model, whereby a time and deformation dependent relaxation modulus is defined. A realistic link is established between the model and real fruits and vegetables by test procedures for determination of the parameters in the governing nonlinear equations. Based on the nonlinear relaxation modulus, mechanical damage of fruits and vegetables is quantified for static compression, transients and vibration loading as well as for combined static and dynamic loading, by equations of contact circle diameter, bruise depth and contact pressure. Distribution of loads over a maximal number of contact points per fruit is linked to geometrical patterns of produce packs. The application of Shock Damage Boundary techniques for produce-package testing is described along with a case study comparing the protective qualities of two types of apple packs. Produce damage quantification by direct fruit inspection in terms of a ‘Bruise Index’ is described, including a practival example, comparing the protective qualities of three types of apple packs in shipping tests. Indirect methods of mechanical injury evaluation, based on weight loss and CO 2 emission differences between bruised and wholesome fruits are also briefly discussed.

Fortschrittsbericht Möglichkeiten der Proteinbewertung

With protein evaluation the changing abilities of food proteins are characterized with regard to their covering the requirements of the organism for protein or amino acids, respectively. The biological value of proteins is influenced by several factors. Measuring the reaction of the whole organism (of man or animal) to the food protein the sum of all influencing factors is covered. Hence, these direct evaluation methods have priority. The general dose-reaction curve demonstrates the direct evaluation methods: The evaluation criteria protein efficiency or minimum protein requirement are presented and the different possibilities of interpretion are compared. Most direct evaluation methods are performed with suboptimal protein supply, therefore values for an optimum protein supply can be derived only with reservation. Improved values for protein evaluation can be obtained from investigations of the protein metabolism. With that the substrat-related evaluation can be more orientated to a organism-related one. Indirect biochemical evaluation methods are less important. That does not concern in-vitro evaluation by amino-acid analysis and/or in-vitro digestibility tests. Possibilities and limits of these methods are discussed.

Deformation of friction-pair rings of end seals

Special requirements are imposed on end seal constructions working under high-pressure conditions. It has been established that with rise in pressure drop the force and thermal loads impair the efficiency of operation of friction pairs, whose sealing surfaces may deviate considerably from the initial plane of contact as a result of deformation. In these cases a dehermetization of the end seals is observed, accompanied by a nonuniform and elevated wear of the friction pair rings, accompanied by the formation of a diffuser or confuser slot at the site of contact after removal of the stress [],2]. Calculation of the deformation characteristics of end-seal friction pairs [3] makes it possible to carry out only a qualitative estimate of the effect of force and thermal stresses on friction-pair rings. However, a direct measurement of the deformations of a friction pair operating under high-pressure conditions is of great interest, since it is then possible to establish the experimental and theoretical interconnections between deformation, hermeticity, and operation reliability of end-seal friction pairs. However, due to the smallness of the angle of rotation of a ring section and the complexity of access into the seal, the usual (direct) methods of measuring deformation are impeded. In this connection, in our experiments indirect methods of evaluation were used, based on measuring the tangent of the deformation angle with the aid of a profilograph-profilometer.

N-Formamido Group Formed in the Place of Thymine Fragment under Gamma Irradiation of DNA. Rapid Indirect Method of Evaluation both in vitro and in vivo Conditions

N-formamido-(DNA) is one of the main lesions formed on the thymidylic fragments of DNA when DNA, in vitro or in vivo conditions, is exposed to ionising radiations. The N-formamido group partly replaces the thymine base in DNA sequence. This article proposes an indirect dosing technique for this damage. The method is based on the release of 14CO2 from the C-2 of the thymine ring. When the pyrimidine ring of the thymidine moiety is broken, N-formamido deoxyribose derivative, carbon dioxide and pyruvamide are formed all in the same reaction. During this investigation the phenomena of protection due to the constituent parts of the cell and to the secondary and tertiary structures of DNA are also evidenced.

Monitoring of midmyocardial and subendocardial pH in normal and ischemic ventricles

Midmyocardial and subendocardial pH monitoring was used as an indirect method for continuous evaluation of regional canine myocardial ischemia. Left ventricular midmyocardial pH (pHm) at 4 mm. depth was monitored in 10 dogs, under resting conditions, by means of a 5 mm. Beckman pH probe. pHm was 6.96 +/- 0.03, recorded at myocardial temperatures of 35 to 37 degrees C. Ischemia was then produced by snare occlusion of the proximal left main coronary artery for 2 minutes. pHm decreased to 6.87 +/- 0.03 (p less than 0.01) at 1 minute and 6.80 +/- 0.04 (p less than 0.005) in 2 minutes. When flow was restored, pHm returned toward normal within 2 minutes (pH 6.86 +/- 0.03) and at 5 minutes had returned to control values (pH 6.93 +/- 0.03). In another 5 dogs under similar conditions, pHm at 4 mm. and subendocardial pH (pHe at 8 mm.) were measured. Baseline pHm (6.97 +/- 0.01) and pHe (6.84 +/- 0.02) levels were significantly different (p less than 0.0005). After 2 minutes of ischemia, pHm was 6.82 +/- 0.03, whereas pHe decreased to 6.78 +/- 0.04 (p less than 0.1). Five minutes after snare release, pHe remained at 6.73 +/- 0.07; pHm (6.93 +/- 0.03) returned to control values. Both pHm (6.93 +/- 0.02) and pHe (6.84 +/- 0.09) levels were normal 15 minutes after release of the snare. The midmyocardium and subendocardium have different pH levels which can be monitored. Ischemia produces different pH patterns in these layers. pHm returns to control values within 5 minutes after 2 minutes of ischemia, whereas pHe remains depressed for at least 5 minutes. pH monitoring provides an accurate and simple method for on-line evaluation of endocardial ischemia.

The evaluation of Δ C° p for acid-base equilibria from pK measurement

The use of the temperature variation of the dissociation constant for evaluating changes in Δ C° p is reviewed with a view to establishing the degree of reliability of such values. Δ C° p values obtained from dissociation constant measurements are compared, where possible, with the calorimetrically determined values. Significant differences are apparent, suggesting serious shortcomings in the indirect methods of evaluation used so far. The related question of the appropriate form of the pK( T) equation is also discussed. When the “most appropriate” form of pK( t), viz a five-constants equation is used with the accurate data of Ives for the dissociation of cyano-acetic acid, according to the method of Clarke and Glew, the results still retain large uncertainties on Δ C° p . Model exact pK data can be calculated from known assumed Δ G°, Δ H°, Δ C° p , first and second temperature derivatives of Δ C° p at a chosen reference temperature. By introducing variations of various magnitudes and signs on these model values, very accurate “experimental-like” pK values can be generated. When these accurate pK values are analysed on the computer, using the method of Clarke and Glew, and the results are compared, it becomes apparent that over the normal experimental range (O°−50°C or 60°C) even very small errors ( ca 0·00025 pK units) can lead to very large uncertainties on Δ C° p (especially at the two extremes of the temperature range) exceeding in some cases 20 cal. The identification of the true Δ C° p ( T) becomes impossible. It is concluded that the dissociation constant method is not capable as yet of furnishing reliable Δ C° p values; the extension of the temperature range to the neighborhood of 100°C and an increase in the degrees of freedom ( eg by measurements at 5° intervals) could combine to furnish fairly reliable Δ C° p values.

An Indirect Method for Evaluation of Left Ventricular Function in Acute Myocardial Infarction

An Indirect Method for Evaluation of Left Ventricular Function in Acute Myocardial Infarction

An indirect method for evaluation of left ventricular function in acute myocardial infarction.

An indirect method for evaluation of left ventricular function in acute myocardial infarction.

An indirect method for evaluation of left ventricular function in acute myocardial infarction.

An indirect estimate of the contractility index, max LV dP/dt/LVEDP, has been examined in 32 patients following acute myocardial infarction (AMI) and in three patients with acute coronary insufficiency (ACI). The index was derived from arterial diastolic pressure (DP) obtained by sphygmomanometer, left ventricular filling pressure (LVFP) obtained by pulmonary artery balloon catheter, and preejection period (PEP) determined from the phonocardiogram, carotid pulse, and ECG. These data were used in the relation (DP-LVFP)/PEP/LVFP (i.e., ΔP/Δt/LVFP) as an approximation of the direct contractility index max dP/dt/LVEDP. While measurements of PEP, DP, and LVFP used independently were not useful in distinguishing patients grouped in surviving AMI, nonsurviving AMI, and ACI categories, the ΔP/Δt/LVFP index showed marked separation of these groups. Because of the simplicity of measurement and minimal intravascular intervention, the index provides a safe and practical means of assessing the degree of left ventricular dysfunction in patients with AMI.