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PubMed2002

Effect of light source and specimen thickness on the surface hardness of resin composite.

PURPOSE: To compare the Knoop hardness of different thicknesses of resin composite irradiated using either a plasma arc curing (PAC) light, or a quartz tungsten halogen (QTH) light. MATERIALS AND METHODS: A 2.5-mm diameter hole was drilled through the center of 2, 3, 4, and 5-mm thick discs of enamel and dentin. This hole was filled with either Filtek P60 or Prodigy Condensable composite and irradiated in bulk using: (a) a PAC light with an 8-mm, 470 nm light guide for 3 seconds, (b) a QTH light with an 8-mm standard light guide for 40 seconds (QTH+S), or (c) a QTH light with a 13/8-mm Turbo light guide for 40 seconds (QTH+T). Immediately after irradiating the composite, the surface hardness was measured at the bottom and then the top. Hardness values were remeasured after 24-hour and 7-day storage in water at 37 degrees C. The hardness values were compared using the Analysis of Variance for Repeated Measures and Least Squares Means test for multiple comparisons (LSM test) at P< 0.05. RESULTS: The power density delivered by each light was: PAC over 1999 mW/cm2, QTH+S 588 mW/cm2, and QTH+T 844 mW/cm2. Both the thickness of the composite and the light source had a significant effect on the hardness. Overall, using the QTH+T produced the highest hardness values and the PAC light the lowest values. For all 2-mm thick specimens, irrespective of the light source, the hardness values at the bottom were not significantly different from their top hardness values measured at the same time. For the 3-mm thick specimens using the QTH+T, the hardness values at the bottom of both composites were not significantly different from their top hardness values at all time intervals. For the 3-mm thick specimens using the QTH+S, the bottom hardness values were not significantly different from those at the top for P60 only, and only at 24 hours and 7 days, but not when measured immediately. For all the 4 and 5-mm thick specimens, the hardness values at the bottom were all significantly different from those at the top measured at the same time interval.

Analysis of Variance↗
PubMed2006

Erection hardness: a unifying factor for defining response in the treatment of erectile dysfunction.

The extensive sildenafil citrate erectile dysfunction (ED) database of double-blind, placebo-controlled clinical trials was examined to determine the relation between erection hardness graded on the Erectile Hardness Grading Scale (EHGS) and (1) erectile function (EF), as assessed by the EF domain of the International Index of Erectile Function (IIEF); (2) frequency of erections hard enough for penetration, as assessed by IIEF Q2; and (3) the percentage of successful sexual intercourse attempts according to patient event logs. Pooled data from 6549 men with ED provided strong proof and improved characterization of the response to sildenafil. Almost half of men with ED and a baseline IIEF EF domain score classified as "severe ED" (< or = 10) shifted to a score classified as "no ED" (> or = 26). Sildenafil recipients showed greater mean improvement from baseline to end point in IIEF Q2 scores versus placebo, regardless of baseline ED severity, and a higher mean percentage of successful sexual intercourse attempts occurred during the last 4 weeks of treatment versus placebo (5.4-fold vs 2.0-fold increase from baseline). At end point, 95% of men who scored "no ED" on the IIEF EF domain and 92% of men who reported "almost always/always" achieving an erection hard enough for penetration (IIEF Q2) had graded their erections hard (rigid) enough for penetration (grade 3) or completely hard and fully rigid (grade 4) during the last 4 weeks of treatment, suggesting that the IIEF EF domain and IIEF Q2 may be good surrogate end points for erection hardness. Furthermore, during the last 4 weeks of treatment, the percentage of grade 3 and/or 4 erections correlated positively with the percentage of successful sexual intercourse attempts. Hence, hard erections may be considered a unifying factor that defines response to ED treatment. Completely hard and fully rigid erections (grade 4) should be recognized as the optimal goal of an ED therapy. Evidence presented here demonstrates that sildenafil significantly improved EF as assessed by the IIEF EF domain and assessments of erection hardness in patients with ED; a dose-response relation was observed in the proportions of men with ED who graded their erections hard (rigid) enough for sexual penetration or completely hard and fully rigid.

Adult↗
PubMed1999

Muscle hardness in patients with chronic tension-type headache: relation to actual headache state.

It has recently been reported that the pericranial muscles in patients with chronic tension-type headache are harder, i.e. have a higher consistency, than in controls. The primary aim of the present study was to investigate whether muscle hardness is influenced by the presence or absence of actual headache and whether hardness is correlated to tenderness. The secondary aim was to compare muscle hardness between patients and healthy controls. Hardness of the trapezius muscle was measured with a hardness meter in 20 patients with chronic tension-type headache and in 20 healthy controls. The patients were examined on 2 days, 1 day with headache and 1 day without headache. Pericranial myofascial tenderness was recorded with manual palpation. In addition, muscle hardness was measured in another five patients out-side headache and in 30 healthy controls. The muscle hardness recorded in patients (n = 20) on days with headache, 98 +/- 26 kPa/cm, did not differ significantly from the muscle hardness recorded on days without headache, 100 +/- 21 kPa/cm, (P = 0.62). The muscle hardness was positively correlated to the local tenderness score recorded from the trapezius muscle both on days with headache (R = 0.52, P = 0.02) and on days without headache (R = 0.53, P = 0.02). The total tenderness score (TTS) recorded in patients on days with headache, 23 +/- 10, was significantly higher than the TTS recorded on days without headache, 15 +/- 11, (P = 0.0001). There was a significant difference between the TTS recorded in patients without headache, 15 +/- 11, and in controls, 4 +/- 4, (P = 0.002). The muscle hardness was significantly higher in patients on days without headache (n = 25), 97 +/- 20 kPa/cm, than in controls (n = 30), 87 +/- 16 kPa/cm (P = 0.03). On basis of previous and present results, we suggest that muscle hardness and muscle tenderness are permanently altered in chronic tension-type headache and not only a consequence of actual pain. In addition, the positive correlation between muscle hardness and tenderness supports the common clinical observation that tender muscles are harder than normal muscles.

Adult↗
PubMed1982

Hardness of the subchondral bone of the patella in the normal state, in chondromalacia, and in osteoarthrosis.

The hardness of bone is its property of withstanding the impact of a penetrating agent. It has been found that articular degenerative changes in, for example, the tibia (knee) are combined with a decrease in the hardness of the subchondral bone. In this investigation the hardness of subchondral bone in chondromalacia and osteoarthrosis of the patella has been analysed and compared with normal subchondral bone. Using an indentation method originally described by Brinell the hardness of the subchondral bone was evaluated in 7 normal patellae, in 20 with chondromalacia and in 33 with osteoarthrosis. A microscopic and microradiographic study of the subchondral bone was carried out simultaneously. Hardness was lowest in the normal material. The mean hardness value beneath the degenerated cartilage differed only slightly from that of the normal material, but the variation of values was increased. The hardness in bone in the chondromalacia area was lower than the hardness in bone covered by surrounding normal cartilage. The mean hardness value in bone beneath normal parts of cartilage in specimens with chondromalacia was higher than the mean hardness value of the normal material. In the microscopic and microradiographic examination it became evident that there was a relationship between trabecular structure and subchondral bone hardness; high values: coarse and solid structure; low values: slender and less regular structure.

Adolescent↗
PubMed2004

Nomograms of sonographic measurements throughout gestation of the fetal hard palate width, length and area.

OBJECTIVE: To assess the feasibility of sonographic depiction of the fetal hard palate and secondarily to create nomograms throughout gestation of its sonographic width, length and area. METHODS: This was a cross-sectional study of pregnant patients between 15 and 41 weeks' gestation. Inclusion criteria consisted of well-established dates (confirmed by early ultrasound), and singleton, non-anomalous fetuses. Sonographic measurements obtained included biparietal diameter, head circumference, abdominal circumference and femur length. Fetal hard palate measurements included maximum width, maximum length and the calculated area. Tables were prepared depicting the estimated mean +/- SD and 5(th), 50(th) and 95(th) centiles at each gestational week between 15 and 41 weeks. Pearson's correlation coefficient and associated P-values for the relationships between fetal hard palate measurements and other sonographic measurements and coefficients of variation for each of the fetal hard palate measurements were calculated. RESULTS: The study included 602 consecutive patients. The mean maternal age was 28.7 +/- 6.3 years, with median gravidity of 2 (range, 1-12) and parity 1 (range, 0-8). All attempts at obtaining fetal hard palate ultrasound measurements were successful. Mean fetal hard palate width (cm) = -0.73579345 + 0.11370432 x GA - 0.00083919 x GA(2) and SD = -0.017842055 + 0.005142475 x GA, where GA is gestational age in weeks. Mean fetal hard palate length (cm) = -0.82020463 + 0.11767777 x GA - 0.00092801 x GA(2) and SD = -0.043064317 + 0.006378869 x GA. Mean fetal hard palate area (cm(2)) = -2.40090641 + 0.17136556 x GA + 0.00097308 x GA(2) and SD = -0.603647741 + 0.040740282 x GA. Sonographic measurements of the fetal hard palate width, length and area correlated significantly and strongly with gestational age (all P < 0.001) and significantly but less strongly with femur length (P = 0.004). CONCLUSION: The fetal hard palate may be depicted sonographically with relative ease between 15 and 41 weeks' gestation and measurements of the fetal hard palate width, length and area correlate well with gestational age, biparietal diameter, abdominal circumference, sonographic estimated fetal weight, and femur length.

Adult↗
PubMed1999

A catheter tactile sensor for measuring hardness of soft tissue: measurement in a silicone model and in an in vitro human prostate model.

Tissue hardness is related to tissue composition, and this is often changed by disease. It is therefore of interest to measure the hardness in an objective and non-invasive way. A tactile sensor based on a vibrating piezoelectric ceramic element in a feedback loop is described. When the sensor touches an object it produces a frequency shift related to the hardness of the object. The aim of this study was to develop an in vitro hardness measurement method using a catheter type version of the sensor. The method was evaluated in an established silicone tissue model and on human prostate tissue in vitro. A linear relationship was found with a high degree of explanation (R2 = 0.98) between a cone penetration hardness standard (DIN ISO 2137) applied to the silicone model and the corresponding frequency shift. The results from measurements on a human prostate tissue sample, fixed with formalin, showed that the relative hardness measured with the tactile sensor correlated (R = -0.96, p < 0.001, N = 60) with the proposed hardness related to the histological composition of the prostate tissue. The results indicated that hardness of prostate tissue, and maybe hardness of human tissue in general, can be expressed according to the cone penetration standard and that the hardness can be measured with this tactile sensory system. These findings hold the promise of further development of a non-invasive tool for hardness measurement in a clinical situation.

Aged↗
PubMed2003

Prediction of tablet hardness and porosity using near-infrared diffuse reflectance spectroscopy as a nondestructive method.

The main objective of this research is to use the near-infrared diffuse reflectance method to evaluate and quantify the effects of hardness and porosity on the near-infrared spectras of tablets. To develop a model equation, validate the model and test the model predictive ability. Seven theophylline tablet formulations of the same composition but with seven different hardness values (3, 6, 8, 10, 12, 15, and 17 kp) were prepared. Another seven theophylline tablets formulation with seven different porosity values (57.4, 50.3, 41.9, 40.3, 39.9, 37.3, and 35.1%) were prepared. Five placebo tablets formulation with different hardness and porosity values were also prepared. Laboratory hardness and porosity values were compared to near-infrared diffuse reflectance data. Linear regression, quadratic, cubic and partial least square techniques were used to determine the relationship between hardness, porosity and the near-infrared spectras. The results demonstrated that an increase in tablet hardness and a decrease in tablets porosity produced an increase in near-infrared absorbance. Series of model equations depending on the mathematical technique used for regression were developed from the calibration of hardness and porosity data using laboratory equipment vs. the near-infrared diffuse reflectance for each formulations. The results of near-infrared hardness and porosity predictions were very similar to laboratory hardness and porosity tests. The near-infrared diffuse reflectance spectroscopy method is an alternative nondestructive method for measurement of hardness and porosity of tablets.

Cellulose↗
PubMed2006

Measurement of tissue hardness: can this be a method of diagnosing compartment syndrome noninvasively in children?

In order to assess the feasibility of using the measurement of tissue hardness as a method of diagnosing compartment syndrome noninvasively in children, a simple hand-held device to measure tissue hardness was fabricated. The relationship between hardness and compartmental pressure was studied in an experimental model and in three fresh amputated lower limbs. Normal tissue hardness of the forearm was measured in 189 children and 20 adults to identify the factors that influence normal tissue hardness. The reproducibility of measurement of tissue hardness was assessed on the experimental model, on the amputated limbs and in normal individuals. Experimental data from this study suggest that there is a nonlinear relationship between intracompartmental pressure and tissue hardness. The study also shows that tissue hardness can be measured reproducibly in the forearm of children with the device. Several factors influence tissue hardness such as the age of the child, the site of measurement on the limb, the hand dominance and active muscle contraction. These factors may affect the specificity of this measure as a screening tool for diagnosing compartment syndrome. Further refinement of the measuring device and well designed clinical trials are needed to establish whether compartmental syndrome can be diagnosed reliably by measuring tissue hardness noninvasively.

Adolescent↗
PubMed2006

Hardness of enamel exposed to Coca-Cola and artificial saliva.

The purpose of this study was to determine the rate of change in indentation hardness of enamel in permanent teeth exposed to Coca-Cola. In a further experiment, the ability of a commercially available artificial saliva to remineralize enamel treated with Coca-Cola was tested. Ten enamel specimens were randomly chosen to be treated with Coca-Cola (experimental groups) and seven with water (control group). The fluids were applied for 1, 2, 3 h and overnight (15 h), washed off with a few drops of water and the moist enamel indentation hardness tested after each interval. With Coca-Cola treatment, the mean enamel hardness was 92.6% (s.d. = 7.9) of the original baseline hardness after 1 h, 93.25% (s.d. = 10.15) after 2 h, 85.7% (s.d. = 12.03) after 3 h and 80.3% after 15 h. The mean indentation hardness of control specimens treated with water was 108.7% (s.d. = 16.09) of the original hardness after 1 h, 99.09% (s.d. = 18.98) after 2 h, 98.97% (s.d. =11.24) after 3 h and 98.42% (s.d. = 22.78) after 15 h. In a separate experiment, the hardness of 9 enamel specimens was tested, as previously described, before and after treatment with Coca-Cola overnight and again after application of artificial saliva for 3 min. Coca-Cola reduced the mean indentation hardness of enamel in the teeth, but the hardness was partially restored with artificial saliva (Salivart) and increased by 18% from the demineralized enamel hardness.

Carbonated Beverages↗
PubMed1978

Direct measurement of myocadial hardness.

Myocardial hardness, defined as resistance to a pitting force, was measured on several sites of the myocardium in 20 anesthetized dogs. The durometer used for hardness measurements consisted of an indentor, 4 mm in diameter, pressed perpendicularly on the myocardium by a calibrated spring (elastic modulus 325 N/m). Hardness changes during the cardiac cycle caused movement of the indentor which interrupted a light beam falling on a photoresistance. Changes in illumination of the photoresistance resulted in resistance changes, which were recorded using a Wheatstone bridge and a DC amplifier. Hardness was expressed in mm of spring shortenings. Balanced in (zero hardness), the indentor protruded 7.2 mm beyond the foot. Thus hardness adequate to press the indentor level with the foot defined as 7.2 mm. The left ventricular pressure (LVP) rise followed slightly the hardness rise (from 29.5 +/- 3.6 msec--mean +/- SEM--for the basal area at the right ventricle to 35.8 +/- 5.9 msec for the basal area of the left ventricle. Apical areas were significantly harder in systole than corresponding basal areas and left ventricular areas had a significantly higher systolic hardness (SH) than corresponding right ventricular areas. Changes in LVP by transfusion bleeding caused almost proportional changes in SH. While using a constant pressure reservoir in left atrium and another in aorta, adrenaline caused a significant increase in SH, decrease in diastolic hardness (DH) and increase in hardness width (WH); calcium chloride caused a nonsignificant increase in SH and WH and a significant decrease in DH; practolol caused a nonsignificant decrease in SH and a significant increase in DH and decrease in WH. Ligation of 3--5 branches of the anterior descending coronary artery resulted in a significant increase in DH and reduction in the WH distally to the ligation during the first 11 min. The WH was significantly reduced as a function of time in both areas (healthy and infarcted) taken collectively. The WH was significantly higher over the healthy area than over the infarcted one at corresponding times.

Animals↗
PubMed2005

Evaluation of adhesion of chairside hard relining materials to denture base polymers.

STATEMENT OF PROBLEM: Removable denture bases are made of modified poly(methyl methacrylate) (PMMA), which has reliable bond strength with resins containing methyl methacrylate (MMA). However, some hard relining materials with different chemical compositions have been reported to have less than adequate bond strength to PMMA denture base polymers. PURPOSE: This in vitro study evaluated the initial bonding properties of chairside hard relining materials to different removable denture base polymers, as well as the structure of the interface. MATERIAL AND METHODS: The tensile strength (MPa) of adhesion of 8 chairside hard relining materials (Original Truliner, GC Reline Hard, Ufigel Hard, Triad Reline, New Truliner, Light Liner, Astron LC Hard, and Flexacryl Hard) was tested against 3 denture base polymers (Ivocap Plus, Paladon 65, and Palapress Vario). Dumbbell-shaped specimens with a 6-mm diameter of bonding surface were used for tensile testing of bond strength (n=5). An MMA containing hard relining material (Original Truliner) was used as a control. Tensile strength of the bond was calculated using the bonding area and maximum force under tension. Statistical analyses of data were conducted with 2-way analysis of variance (alpha=.05). The influence of the bonding agents and the relining materials on the PMMA denture base surface layer and its structure were investigated. The depths of the swollen layers were measured with a transmission light microscope. Fracture surfaces after testing were also visually evaluated. Chemical analyses of all materials prior to testing were performed using high-performance liquid chromatography. RESULTS: Significant differences were found among tensile bond strengths of chairside hard relining materials to PMMA denture base polymers forming 3 different groups (P<.001). No significant difference among different denture base polymers was found with regard to tensile strength of adhesion (P=.918), but the interaction term between hard relining material and denture base polymer was found to be significant (P<.001). The tensile bond strength of the relining materials and denture base polymers was found to range from 8% to 60% of the strength of the PMMA denture base polymers. CONCLUSION: The chemical composition of the bonding agents and the relining materials and their combinations affected the depth of the swollen layers of the denture base polymers and the tensile strength of adhesion.

Acrylic Resins↗
PubMed2002

Evaluating the role of ion composition on the toxicity of copper to Ceriodaphnia dubia in very hard waters.

The mitigating effect of increasing hardness on metal toxicity is reflected in water quality criteria in the United States over the range of 25-400 mgl(-1) (as CaCO(3)). However, waters in the arid west of the US frequently exceed 400 mgl(-1) hardness, and the applicability of hardness-toxicity relationships in these waters is unknown. Acute toxicity tests with Ceriodaphnia dubia were conducted at hardness levels ranging from approximately 300 to 1,200 mgl(-1) using reconstituted waters that mimic two natural waters with elevated hardness: (1) alkaline desert southwest streams (Las Vegas Wash, NV), and (2) low alkalinity waters from a CaSO(4)-treated mining effluent in Colorado. The moderately-alkaline EPA synthetic hard water was also included for comparison. Copper toxicity did not consistently vary as a function of hardness, but likely as a function of other water quality characteristics (e.g., alkalinity or other correlated factors). The hardness equations used in regulatory criteria, therefore, may not provide an accurate level of protection against copper toxicity in all types of very hard waters. However, the mechanistic Biotic ligand model generally predicted copper toxicity within +/-2X of observed EC(50) values, and thus may be more useful than hardness for modifying water quality criteria.

Animals↗
PubMed1995

The relationship between stool hardness and stool composition in breast- and formula-fed infants.

"Constipation" and "hard stools" are associated with formula feeding of both term and preterm infants and, in the latter, can lead to life-threatening complications. This study tested the hypothesis that stool hardness is related to excretion of fatty acid (FA) soaps in term infants, and in the extreme to milk bolus obstruction in premature infants. Stools (n = 44) were collected from 20 formula-fed and 10 breast-fed infants aged 6 weeks and were classified using visual charts for stool hardness on a 5-point scale (1, watery; 5, hard). Stools were analysed for nitrogen, minerals, and lipid, the latter divided between the soap and nonsoap fractions. We explored the relationship between stool hardness or solids content and stool constituents, relative to both wet and dry weight. Calcium and FA soaps were the dominant factors significantly related to stool solids and hardness score across the breast- and formula-fed groups. An 8% increase in stool dry weight FA soap content corresponded to a 1-point change in stool hardness score. Stools from formula-fed infants had a higher solids content and were classified as significantly harder than those from breast-fed infants (hardness scores, 4.0 +/- 0.5 versus 2.6 +/- 0.7, mean +/- SD) and on both a wet- and dry-weight basis contained severalfold higher levels of minerals and lipid and considerably less carbohydrate. Differences in lipids between formula- and breast-fed infants' stools were due almost entirely to FAs (mainly C16:0 and C18:0) excreted as soaps (27.7 +/- 7.5% compared to 3.1 +/- 4.1% of dry weight), suggesting the groups differed markedly in their handling of saturated FAs. An inspissated stool sample from a premature infant requiring surgical disempaction of an obstructed small intestine was found to be enriched in FA and calcium relative to the preterm formula. FA soaps, predominantly saturated, accounted for one third of the stool dry weight. These data support the hypothesis that calcium FA soaps are positively related to stool hardness; we speculate that this may, at least in part, explain the greater stool hardness in formula- versus breast-fed infants and milk bolus obstruction in preterm infants. This conclusion is consistent with the physical properties of calcium FA soaps.

Breast Feeding↗
PubMed1997

Soft-copy versus hard-copy cranial sonography: intraobserver agreement and workstation efficiency.

OBJECTIVE: The objective of the study was to determine the intraobserver agreement, confidence level, and efficiency in interpretation of soft-copy (workstation) versus hard-copy (laser-printed film) sonograms of the cranium. MATERIALS AND METHODS: Cranial sonograms of 100 premature infants were randomly reviewed twice on both soft-copy and hard-copy images by three observers and were graded for hemorrhage using a five-level scale. The kappa statistic was calculated to measure intraobserver agreement. Differences in agreement were tested for statistical significance with a test for marginal homogeneity. Observers rated their confidence in interpretation using a six-point ordinal scale. Total viewing time was recorded, and videotaped sessions were analyzed for image handling time (opening each case, closing each case, and selecting the next case) and interpretation time. RESULTS: For soft copy versus hard copy, the mean kappa value was .73; for hard-copy 1 versus hard-copy 2, .71; and for soft-copy 1 versus soft-copy 2, .65. None of these differences was statistically significant (p > .05). The mean confidence score was the same for soft copy (5.3) and hard copy (5.3). On average, the observers needed 24 min longer to review 100 studies on soft copy than on hard copy. Opening and closing times for soft copy were significantly faster than for hard copy (p = .0001); however, case selection for soft copy, which was not needed for hard copy, took 4.69-9.09 sec per case. Extrapolated to 100 cases, case selection accounted for 8-15 min of viewing time. CONCLUSION: Radiologist agreement and confidence in the interpretation of cranial sonograms for hemorrhage was the same for soft copy and hard copy. However, viewing times were longer for soft copy. Elimination of inefficiency in case selection could improve image-handling time.

Cerebral Hemorrhage↗
PubMed1999

Baseball hardness as a risk factor for eye injuries.

BACKGROUND: Baseball is the leading cause of sports-related eye injuries in young persons. It is known that softer baseballs reduce the potential for brain and cardiac injury, but it has been speculated that softer baseballs may increase eye injuries by intruding more into the orbit. It also has been claimed that softer baseballs would change the "feel" of the game. OBJECTIVES: To determine the orbital intrusion and eye injury potential of baseballs of varying hardness, and whether a player can feel the difference between these different baseballs. MAIN OUTCOME MEASURES: Orbital force and penetration of baseballs of various hardness into an artificial orbit. Ability of subjects of varying age and baseball experience to determine the hardness of baseballs. RESULTS: The peak orbital force and force onset rate from softer baseballs, at all impact velocities, were less than the force and force onset rate from baseballs that had hardness equal to, or greater than, major league baseballs. The softest (10% of major league hardness) baseballs intruded into the orbit significantly more than balls that were 15% of major league hardness or harder. Children younger than 14 years could not differentiate balls 15% of major league hardness or harder, and adults could not differentiate 20% of major league hardness or harder from each other or from major league balls. CONCLUSION: The potential for injury to the unprotected eye from soft baseballs is significant, but not greater than that from a major league baseball. Baseballs that are 15% to 20% of major league ball hardness are recommended for youth baseball because these balls feel like major league balls, reduce the potential for brain injury and commotio cordis, cause less pain on impact, and do not increase the potential for eye injury to the unprotected player. Eye injuries in youth baseball could be minimized by the use of protective eyewear that conforms to the standard specifications of the American Society of Testing and Materials (Philadelphia, Pa), standards F910 (for batters and baserunners) and F803 (for fielders).

Adolescent↗
PubMed2002

Mapping QTLs for grain hardness and puroindoline content in wheat ( Triticum aestivum L.).

Genes for puroindoline-a (Pin-a), puroindoline-b (Pin-b) and grain-softness proteins (GSP) have been shown to be linked to the dominant Ha locus responsible for the soft texture of the grain. Though linkage has been demonstrated of the puroindoline genes to the Ha locus, there is no clear evidence that puroindoline content is the product of the gene Ha. A segregating population of 115 recombinant inbred lines (RILs) originating from a cross between the hexaploid Synthetic wheat ( Triticum durum x Aegilops tauschii, W 7984) and the cultivar 'Opata' (M 85) was studied in two different experimental years to detect Quantitative Trait Loci (QTLs) for three traits: grain hardness (Hard), puroindoline-a (Pin-a) and puroindoline-b (Pin-b) contents. The detection of QTLs was performed using marker linear regression. Negative correlation coefficients (-0.86 and -0.80) were identified between grain hardness and puroindoline content (a and b, respectively) on data obtained in 1996. Results obtained in 1999 confirmed the negative correlation between Hard and Pin-a (-0.73); however a positive correlation coefficient was found with Pin-b content (0.41). Total phenotypic variation explained by each QTL was calculated (R2). For each of the Hard, Pin-a and Pin-b traits one major QTL was detected on the short arm of chromosome 5D, located close to the mta9 allele (puroindoline-a). For the first year (1996) the QTL in this region explained around 63% of the phenotypic variability in grain hardness, 77% in Pin-a and 45% in Pin-b contents. These values were confirmed in trials carried out in 1999 with a R2 value of 0.71, 0.72 and 0.25 for Hard, Pin-a and Pin-b, respectively. In 1996 and 1999 a second major QTL was detected for grain hardness on the long arm of the same chromosome. Present results indicate that it cannot be definitely concluded that puroindoline content represents a linear explanation for variations in grain hardness.

Chromosome Mapping↗
PubMed1995

Bite force displayed during assessment of hardness in various texture contexts.

The relationship between mastication pattern, mechanical properties of the food bolus and texture perception are not fully understood, though the mastication process is known to adjust to different textural properties of foods. This study investigated the role of the bite force as one major aspect in hardness assessment of materials exhibiting simple mechanical properties over a wide hardness range. Elastic, plastic and brittle materials (silicone elastomers, waxes and pharmaceutical tablets, respectively) were tested. The rheological characteristics of these products were measured. For each product, one to four differential thresholds were determined at different points on a hardness scale by 10 individuals free of dental pathology. Bite forces were recorded by placing a small intraoral load cell under each sample. To assess the influence of the nature of the applied force, bites were made either directly on to the sample or on a metal disc placed between the teeth and the sample. As the individuals had to break the brittle products to perceive any hardness difference, bite forces were very closely correlated with the hardness of the products (r = 0.99). For plastic products, bite forces again correlated with the hardness (r = 0.96), even though individuals could stop biting at any time during the plastic deformation. Hardness perception of brittle and plastic products depends directly on sensory information about the bite force. However, hardness assessment of elastic products was obtained under constant bite force; here, the resulting deformation may provide sensory information about hardness.

Adult↗
PubMed2004

Hard palate mucosal grafts in oculoplastic surgery: donor site lessons.

PURPOSE: Hard palate mucosal grafts have been used successfully in posterior lamellar reconstruction. Atypical surgical findings, techniques, and complications related to the hard palate donor site are reported herein. DESIGN: Interventional case series. METHODS: The medical records of five patients who were cared for in an institutional practice between 1987 and 2002 were retrospectively reviewed. All patients had unusual donor site findings discovered during or after hard palate mucosal grafting for eyelid or socket reconstruction. RESULTS: Seven eyelid reconstructions with hard palate grafts were performed on the five patients (three male, two female), with an age range of 14 to 73 years at surgery. Patients were followed for an average of 6 years (range: 9 months to 11 years). Unusual hard palate findings during surgery or the postoperative period included hard palate and maxillary sinus malignancy, torus palatinus, and persistent donor site bleeding that provoked gastric variceal bleeding in a patient with preexisting liver disease. Atypical surgical techniques included both inadvertent and intentional harvesting of hard palate tissue over the midline palatine raphe. CONCLUSION: Hard palate grafting is a successful and commonly practiced approach to eyelid and socket reconstruction. An awareness of unusual anatomic findings or techniques associated with the hard palate donor site may improve surgical outcomes and decrease patient morbidity.

Adolescent↗