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Sample records for bite force measurements

  1. Bite Forces and Their Measurement in Dogs and Cats

    Directory of Open Access Journals (Sweden)

    Se Eun Kim

    2018-04-01

    Full Text Available Bite force is generated by the interaction of the masticatory muscles, the mandibles and maxillae, the temporomandibular joints (TMJs, and the teeth. Several methods to measure bite forces in dogs and cats have been described. Direct in vivo measurement of a bite in dogs has been done; however, bite forces were highly variable due to animal volition, situation, or specific measurement technique. Bite force has been measured in vivo from anesthetized dogs by electrical stimulation of jaw adductor muscles, but this may not be reflective of volitional bite force during natural activity. In vitro bite forces have been estimated by calculation of the force produced using mechanical equations representing the jaw adductor muscles and of the mandible and skull structure Bite force can be estimated in silico using finite element analysis (FEA of the computed model of the anatomical structures. FEA can estimate bite force in extinct species; however, estimates may be lower than the measurements in live animals and would have to be validated specifically in domestic dogs and cats to be reliable. The main factors affecting the bite forces in dogs and cats are body weight and the skull’s morphology and size. Other factors such as oral pain, TMJ disorders, masticatory muscle atrophy, and malocclusion may also affect bite force. Knowledge of bite forces in dogs and cats is essential for various clinical and research fields such as the development of implants, materials, and surgical techniques as well as for forensic medicine. This paper is a summary of current knowledge of bite forces in dogs and cats, including the effect of measurement methods and of other factors.

  2. Bite force measurement based on fiber Bragg grating sensor

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    Padma, Srivani; Umesh, Sharath; Asokan, Sundarrajan; Srinivas, Talabattula

    2017-10-01

    The maximum level of voluntary bite force, which results from the combined action of muscle of mastication, joints, and teeth, i.e., craniomandibular structure, is considered as one of the major indicators for the functional state of the masticatory system. Measurement of voluntary bite force provides useful data for the jaw muscle function and activity along with assessment of prosthetics. This study proposes an in vivo methodology for the dynamic measurement of bite force employing a fiber Bragg grating (FBG) sensor known as bite force measurement device (BFMD). The BFMD developed is a noninvasive intraoral device, which transduces the bite force exerted at the occlusal surface into strain variations on a metal plate. These strain variations are acquired by the FBG sensor bonded over it. The BFMD developed facilitates adjustment of the distance between the biting platform, which is essential to capture the maximum voluntary bite force at three different positions of teeth, namely incisor, premolar, and molar sites. The clinically relevant bite forces are measured at incisor, molar, and premolar position and have been compared against each other. Furthermore, the bite forces measured with all subjects are segregated according to gender and also compared against each other.

  3. Assessment of masticatory function using bite force measurements in patients treated for mandibular fractures.

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    Sybil, Deborah; Gopalkrishnan, K

    2013-12-01

    Bite force measurements are excellent criteria for assessment of masticatory efficiency. The purpose of this study was to assess the effect of mandibular fractures on the bite forces of patients treated for such fractures. Patients who were surgically treated for isolated mandibular fractures in the Department of Oral and Maxillofacial Surgery from January 2006 to December 2007 were included in the study. Patients were asked to bite on a bite force transducer on the first, fourth, sixth, and ninth postoperative weeks. The bite force values were compared with those of age, sex, and weight-matched controls. A total of 60 patients were included in the study. It was found that maximum bite forces in patients were significantly less than in controls for several weeks after surgery. After the ninth postoperative week, the maximum bite force measured  80% the normal in patients with isolated parasymphysis fractures. The same values reduced to < 60% in patients with fractures of angle and parasymphysis and < 70% in patients with fractures of parasymphysis and condylar complex. An inverse relationship was found between the bite force values and the number of fractures of the mandible. We also found lower bite forces and longer period for normalization in patients who had fractures in those regions of the mandible which are more significantly associated with the masticatory apparatus for example angle or condyle of the mandible.

  4. A validation study of a new instrument for low cost bite force measurement.

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    Testa, Marco; Di Marco, Anna; Pertusio, Raffaele; Van Roy, Peter; Cattrysse, Erik; Roatta, Silvestro

    2016-10-01

    Quantitative assessment of force in masticatory muscles is not a routine clinical test, probably due to the lack of an "easy-to-use" device. Aim of this study is (1) to present a low cost bite force instrument located in a custom-made housing, designed to guarantee a comfortable and effective bite action, (2) to evaluate its mechanical characteristics, in order to implement it in clinical settings and in experimental setups. Linearity, repeatability and adaptation over time were assessed on a set of four different sensors in bare and housed condition. Application of the housing to the transducer may appreciably alter the transducer's response. Calibration of the housed transducer is thus necessary in order to correctly record real bite force. This solution may represent a low cost and reliable option for biting force measurement and objective assessment of individual force control in the scientific and clinical setting. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Dynamic functional force measurements on an anterior bite plane during the night.

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    Wichelhaus, Andrea; Hüffmeier, Stefan; Sander, Franz-Günter

    2003-11-01

    Anterior bite planes are used in removable and fixed appliance treatment. In removable appliance treatment the question arising is whether the delivered forces can achieve active intrusion in terms of their amplitude and duration. In fixed appliance treatment, the force effect on the incisors and associated pathologic side effects, in particular under the application of intrusion mechanics, have to be considered. The aim of the present study was to investigate the effects of an anterior bite plane during the night. For this purpose ten subjects underwent nocturnal sleep investigations by means of a telemetric system. A silicon force sensor was integrated into an anterior bite plane for continuous measurement of bite forces and of the frequency of occlusal contact with the plate. The occlusal forces exerted on the anterior bite planes ranged between 3 and 80 N. The average forces were 5.5-24 N. The number of occlusal contacts varied between 39 and 558, with forces of between 7 and 9 N being registered in most cases. Major interindividual differences were detected in the magnitude of the force as well as in bite frequency. The intraindividual pattern of arising occlusal forces showed an intermittent force effect. No significant differences were found with regard to gender or growth pattern. In subjects with removable appliances, no active intrusion of teeth is possible during the night owing to the small number of occlusal contacts. Due to the partially very high forces in fixed appliance therapy, the integration of an anterior bite plane has to be assessed as critical in patients with unfavorable root geometry or bruxism.

  6. Reliable quantification of bite-force performance requires use of appropriate biting substrate and standardization of bite out-lever.

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    Lappin, A Kristopher; Jones, Marc E H

    2014-12-15

    Bite-force performance is an ecologically important measure of whole-organism performance that shapes dietary breadth and feeding strategies and, in some taxa, determines reproductive success. It also is a metric that is crucial to testing and evaluating biomechanical models. We reviewed nearly 100 published studies of a range of taxa that incorporate direct in vivo measurements of bite force. Problematically, methods of data collection and processing vary considerably among studies. In particular, there is little consensus on the appropriate substrate to use on the biting surface of force transducers. In addition, the bite out-lever, defined as the distance from the fulcrum (i.e. jaw joint) to the position along the jawline at which the jaws engage the transducer, is rarely taken into account. We examined the effect of bite substrate and bite out-lever on bite-force estimates in a diverse sample of lizards. Results indicate that both variables have a significant impact on the accuracy of measurements. Maximum bite force is significantly greater using leather as the biting substrate compared with a metal substrate. Less-forceful bites on metal are likely due to inhibitory feedback from mechanoreceptors that prevent damage to the feeding apparatus. Standardization of bite out-lever affected which trial produced maximum performance for a given individual. Indeed, maximum bite force is usually underestimated without standardization because it is expected to be greatest at the minimum out-lever (i.e. back of the jaws), which in studies is rarely targeted with success. We assert that future studies should use a pliable substrate, such as leather, and use appropriate standardization for bite out-lever. © 2014. Published by The Company of Biologists Ltd.

  7. Bite force and dental implant treatment: a short review

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    Flanagan D

    2017-06-01

    Full Text Available Dennis Flanagan1,2 1Department of Dental Medicine, Implantology LUdeS Foundation, Ricasoli, Malta; 2Private Practice, Willimantic, CT, USA Abstract: Dental implants are placed endosseously, and the bone is the ultimate bearer of the occlusal load. Patients are not uniform in the maximum bite force they can generate. The occlusal biting load in the posterior jaw is usually about three times of that found in the anterior. It is possible for supporting implants to be overloaded by the patients’ biting force, resulting in bone loss and failure of the fixture. Bite force measurement may be an important parameter when planning dental implant treatment. Some patients can generate extreme biting loads that may cause a luxation of the fixture and subsequent loss of osseointegration. A patient with low biting force may be able to have a successful long-term outcome even with poor anatomical bone qualities. Patients with a high bite force capability may have an increased risk for late component fracture or implant failure. There is no correlation of any bite force value that would indicate any overload of a given implant in a given osseous site. Nonetheless, after bite force measurement, a qualitative judgement may be made by the clinician for the selection of an implant diameter and length and prosthetic design. Keywords: occlusal load, newtons, oral function, force, sensor, software

  8. Proximate determinants of bite force in Anolis lizards.

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    Wittorski, Antoine; Losos, Jonathan B; Herrel, Anthony

    2016-01-01

    Performance measures associated with the vertebrate jaw system may provide important insights into vertebrate ecology and evolution because of their importance in many ecologically relevant tasks. Previous studies have shown that in many taxa, evolution toward higher bite force has gone hand in hand with the evolution of larger body size. However, independent of differences in overall body size, bite force may vary depending on head size and shape as well. Moreover, the underlying musculature may also drive variation in bite force. Here, we investigate the proximate determinants of bite force in lizards of the genus Anolis. We dissected the jaw muscles and quantified muscle mass, fibre length, and cross-sectional area. Data were analysed for both sexes independently given the sexual dimorphism detected in the dataset. Our results show that the traits that explain bite force are similar in both males and females with overall body size and muscle mass being the principal determinants. Among the different muscles examined, the adductor externus and the pseudotemporalis groups were the best determinants of bite force. However, models run for males predicted the variation in bite force better than models for females, suggesting that selection on morphology improving bite force may be stronger in males. © 2015 Anatomical Society.

  9. The force magnitude of a human bite precisely measured at the molar intercuspidation using FBG: part II

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    Marin, Gabriela C.; Milczewski, Maura S.; Abe, Ilda; Cidade, Fernando N.; Souza, Mauren A.; Kalinowski, Hypolito J.

    2015-09-01

    This study describes the evolution of a punctual method to determine the bite force. Now the fiber Bragg grating sensor is encapsulated in minimal material between uppers and lowers first molars, at the moment of occlusion, avoiding precontacts between the other teeth in a dentition model. The gypsum dentition castings were performed in semi-adjustable articulator in the occluded situation to maintain angulations of the occlusal plane of a volunteer. The sensor was characterized using loads from 0 to 90 N. Forces of about 0.0112 nm/N were found between right uppers and lowers first molars.

  10. Clinical significance of isometric bite force versus electrical activity in temporal and masseter muscles

    DEFF Research Database (Denmark)

    Bakke, Merete; Michler, L; Han, K

    1989-01-01

    bite force was 480 Newton (N) in control subjects and 387 N in patients, with corresponding bilateral values of 347 N and 230 N. At predetermined levels of contraction, temporalis and masseter activity were linearly related. Correlations of bite force and activity in short static contractions were......Bite force and activity in temporal and masseter muscles during biting and chewing were recorded in 19 control subjects and 23 subjects with symptoms and signs of functional disorders of the craniomandibular system. The entire group comprised 13 men and 29 women, 14-63 yr of age. Maximal unilateral...... significant with respect to unilateral, but not to bilateral force measurements. Only in the masseter muscle was strength of dynamic contractions during chewing significantly correlated to bite force. With the present method it was demonstrated that unilateral bite force is a simple clinical indicator...

  11. Maximum Bite Force Analysis in Different Age Groups

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    Takaki, Patricia

    2014-04-01

    Full Text Available Introduction Maximum bite force (MBF is the maximum force performed by the subject on the fragmentation of food, directly related with the mastication and determined by many factors. Objective Analyze the MBF of subjects according to age groups. Methods One hundred individuals from the city of São Paulo were equally divided according to age groups and gender. Each individual submitted to a myotherapy evaluation composed of anthropometric measurements of height and weight to obtain body mass index (BMI, using a tape and a digital scale (Magna, G-life, São Paulo, and a dental condition and maximum bite force evaluation, using a digital dynamometer model DDK/M (Kratos, São Paulo, Brazil, on Newton scale. The dental and bite force evaluations were monitored by a professional from the area. Analysis of variance was used with MBF as a dependent variable, age group and gender as random factors, and BMI as a control variable. Results Till the end of adolescence, it was possible to observe a decrease in MBF in both sexes, with the male force greater than the female force. In young adults, the female force became greater the males, then decreased in adulthood. There was no correlation between MBF and BMI. Conclusion There are MBF variations that characterizes the human development stages, according to age groups.

  12. Maximum bite force analysis in different age groups.

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    Takaki, Patricia; Vieira, Marilena; Bommarito, Silvana

    2014-07-01

    Introduction Maximum bite force (MBF) is the maximum force performed by the subject on the fragmentation of food, directly related with the mastication and determined by many factors. Objective Analyze the MBF of subjects according to age groups. Methods One hundred individuals from the city of São Paulo were equally divided according to age groups and gender. Each individual submitted to a myotherapy evaluation composed of anthropometric measurements of height and weight to obtain body mass index (BMI), using a tape and a digital scale (Magna, G-life, São Paulo), and a dental condition and maximum bite force evaluation, using a digital dynamometer model DDK/M (Kratos, São Paulo, Brazil), on Newton scale. The dental and bite force evaluations were monitored by a professional from the area. Analysis of variance was used with MBF as a dependent variable, age group and gender as random factors, and BMI as a control variable. Results Till the end of adolescence, it was possible to observe a decrease in MBF in both sexes, with the male force greater than the female force. In young adults, the female force became greater the males, then decreased in adulthood. There was no correlation between MBF and BMI. Conclusion There are MBF variations that characterizes the human development stages, according to age groups.

  13. Bite force evaluation in subjects with cleft lip and palate

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    Carla Renata Sipert

    2009-04-01

    Full Text Available The purpose of this study was to evaluate the masticatory function of subjects with cleft lip and palate by analyzing the bite force developed by these individuals. Bite force was evaluated in a group of 27 individuals with repaired unilateral cleft lip and palate (14 males and 13 females - aged 18-26 years and compared to the data achieved from a group of 20 noncleft subjects (10 males and 10 females - aged 18-26 years. Measurement was achieved on three positions within the dental arch (incisors, right molars and left molars, three times at each position considering the highest value for each one. Statistical analysis was performed by ANOVA and Mann-Whitney test ( α = 5%. There was a significant deficit in bite force in male individuals with cleft lip and palate compared to the male control group (p=0.02, p=0.004, p=0.003 for incisors, right and left molars, respectively. For the female group, the difference was not statistically significant (p=0.79, p=0.06, p=0.47. In the group of individuals with clefts, 92.6% were under orthodontic treatment, which could be a reason for the present findings, since it can decrease the bite force more remarkably in males than in females. In conclusion, the bite force is significantly reduced in men when comparing the cleft group to the noncleft group. In females, this reduction was not significant in the same way. However, the main reason for this reduction and for the different behavior between genders should be further investigated.

  14. BITE-FORCE ENDURANCE IN PATIENTS WITH TEMPOROMANDIBULAR-JOINT OSTEOARTHROSIS AND INTERNAL DERANGEMENT

    NARCIS (Netherlands)

    STEGENGA, B; BROEKHUIJSEN, ML; DEBONT, LGM; VANWILLIGEN, JD

    1992-01-01

    The aim of this study was to investigate the potential clinical relevance of testing bite force endurance in patients with articular temporomandibular disorders. The endurance of a 50 N bite force was measured in 51 patients with painful temporomandibular joint disorders. The results were compared

  15. Poisonous animal bites in the Israel Defense Forces.

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    Haviv, J; Huerta, M; Shpilberg, O; Klement, E; Ash, N; Grotto, I

    1998-01-01

    Soldiers in field units of the Israel Defense Forces (IDF) are susceptible to injury by various poisonous animals during training and operations. Bites and envenomations by animals such as snakes, scorpions, and spiders can be painful and debilitating, and at times life-threatening. We have examined the extent of exposure of IDF soldiers to snake and arthropod bites and the morbidity resulting from these encounters. All reports of IDF soldiers who sought medical attention for snake or arthropod bites between the years 1993-1997 were reviewed at the IDF Medical Corps Headquarters. Monthly distribution of cases was noted for all years, and geographic distribution was studied for all 1997 cases. Over the period 1993-1997 there was a yearly rate of 32-52 physician visits per 100,000 soldiers due to snakebites (mean 43.6/100,000), and 1370-1729 physician visits per 100,000 soldiers due to arthropod bites (mean 1478/100,000). There is a clear overall increase in snake and arthropod bites during the spring and summer months, with a peak in snakebites in May and in arthropod bites in August. 58% of all snakebites in Israel were reported in the central region, with 33% occurring in the south, and 9% in the north of the country. No fatalities due to envenomations have been reported in the IDF in recent years. Poisonous animal species pose a significant threat to the soldiers of the IDF. Overall, envenomation is a common and widespread problem that has significant impact on the military medical system, especially during the spring and summer months. It is possible through institution of proper preventive measures to decrease the exposure of IDF personnel to this environmental hazard.

  16. Effects of strong bite force on the facial vertical dimension of pembarong performers

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    C. Christina

    2017-06-01

    Full Text Available Background: A pembarong performer is a reog dancer who bites on a piece of wood inserted into his/her mouth in order to support a 60 kg Barongan or Dadak Merak mask. The teeth supporting this large and heavy mask are directly affected, as the strong bite force exerted during a dance could affect their vertical and sagital facial dimensions. Purpose: This study aimed to examine the influence of the bite force of pembarong performers due to their vertical and sagital facial dimensions. Methods: The study reported here involved fifteen pembarong performers and thirteen individuals with normal occlusion (with specific criteria. The bite force of these subjects was measured with a dental prescale sensor during its centric occlusion. A cephalometric variation measurement was subsequently performed on all subjects with its effects on their vertical and sagital facial dimensions being measured. Results: The bite force value of the pembarong performers was 394.3816 ± 7.68787 Newtons, while the normal occlusion was 371.7784 ± 4.77791 Newtons. There was no correlation between the bite force and the facial sagital dimension of these subjects. However, a significant correlation did exist between bite force and lower facial height/total facial height (LFH/TFH ratio (p = 0.013. Conversely, no significant correlation between bite force and posterior facial height/total facial height (PFH/TFH ratio (p = 0.785 was detected. There was an inverse correlation between bite force and LFH/TFH ratio (r = -.464. Conclusion: Bite force is directly related to the decrease in LFH/TFH ratio. Occlusal pressure exerted by the posterior teeth on the alveolar bone may increase bone density at the endosteal surface of cortical bone.

  17. Three-dimensional analyses of human bite-force magnitude and moment.

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    van Eijden, T M

    1991-01-01

    The effect of the three-dimensional orientation of occlusal force on maximal bite-force magnitude was examined in seven human subjects at three different unilateral anteroposterior bite positions (canine, second premolar and second molar). At each position, bite-force magnitude was registered in 17 precisely defined directions using a three-component force transducer and a feedback method. In addition, to assess the efficiency of transfer of muscle to bite force, for bites produced in the sagittal plane, moment-arm length was determined and the produced bite-force moment calculated. The results showed that the largest possible bite force was not always produced in a direction perpendicular to the occlusal plane. Generally, maximal bite force in medial and posterior directions was larger than that in, respectively, corresponding lateral and anterior directions. In each direction the produced force was larger at the posterior bite point than at the anterior bite point. The combined moment produced by the jaw muscles was largest for vertical bites, smallest for posteriorly directed bites and intermediate for anteriorly directed bites. In the case of vertically and anteriorly directed bites the produced moment did not vary significantly with the bite position. Hence, for these bite positions the jaw closing moment of the muscles must have kept constant. In the case of posteriorly directed bites the produced moment decreased when bite position changed from the anterior to the posterior side of the dentition. This indicated that jaw muscle activity had declined.

  18. Muscle thickness, bite force, and craniofacial dimensions in adolescents with signs and symptoms of temporomandibular dysfunction.

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    Pereira, Luciano José; Gavião, Maria Beatriz Duarte; Bonjardim, Leonardo Rigoldi; Castelo, Paula Midori; van der Bilt, Andries

    2007-02-01

    Ultrasonography has been used to determine the association between muscle thickness, temporomandibular dysfuntion (TMD), facial morphology, and bite force. The aim of this study was to evaluate signs and symptoms (SS) of TMD using the craniomandibular index (CMI), masseter and anterior temporalis thickness, facial dimensions, and bite force in adolescents (12-18 years of age): 20 (10 males and 10 females) with SSTMD and 20 without (control, matched for age and gender). Ultrasonography was carried out using Just-Vision 200, and bite force measured with a pressure transducer. The measurements undertaken on the cephalograms included anterior (n-gn, n-Me, sp-gn) and posterior (S-tgo) facial dimensions, jaw inclination (NSL/ML), vertical jaw relationship (NL/ML), gonial angle (ML/RL), and overbite and overjet. The data were analysed with analysis of variance, Pearson's and Spearman's correlation and multiple regression. The SSTMD group showed a smaller bite force than the controls (P influences facial dimensions and bite force in adolescents with SSTMD.

  19. Risk factors for low molar bite force in adult orthodontic patients

    DEFF Research Database (Denmark)

    Andersen, Malene Krogh; Sonnesen, Ane Liselotte

    2013-01-01

    sequentially admitted for conventional orthodontic treatment. All subjects had moderate to severe malocclusions. Bite force was measured by a pressure transducer, craniofacial dimensions and head posture were measured on profile radiographs, number of teeth in contact were evaluated with a plastic strip...... dimensions as mandibular prognathia (S-N-Pg, P angle (ML/RL, P ... showed that gender (P angle (P

  20. A preliminary study to find out maximum occlusal bite force in Indian individuals

    DEFF Research Database (Denmark)

    Jain, Veena; Mathur, Vijay Prakash; Pillai, Rajath

    2014-01-01

    bite force was recorded on both (right and left) sides using a specially designed piezoelectric transducer based device. RESULTS: The MMBF in Indian individuals was found to be 372.39 ± 175.93 Newton (N). Males had significantly higher (P = 0.000) MMBF (448.47 ± 191.82 N) as compared to females (296......PURPOSE: This preliminary hospital based study was designed to measure the mean maximum bite force (MMBF) in healthy Indian individuals. An attempt was made to correlate MMBF with body mass index (BMI) and some of the anthropometric features. METHODOLOGY: A total of 358 healthy subjects in the age...

  1. The effects of stretching exercise for upper trapezius on the asymmetric rate of bite force.

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    Lee, Bomjin; Lee, Joongsook; Yang, Jeongok; Heo, Kwangjin; Hwang, Hojin; Kim, Boyoung; Han, Dongwook

    2015-07-01

    [Purpose] The purpose of this study was to observe the effects of stretching the upper trapezius muscle on the asymmetric rate of bite force. [Subjects] Forty-seven female university students who had all their original teeth, had no disorders in the temporomandibular joints, and had never worn braces; participated in this study. [Methods] An occlusometer was used to measure biting forces. Subsequently, stretching exercises of the upper trapezius were performed. The subjects were divided into 3 groups at the start of the testing: the asymmetric rate of the first group was less than 10%; the asymmetric rate of the second group was between 10% and 20%; and the asymmetric rate of the third group was more than 20%. The stretching exercises were done on the dominant side of the upper trapezius. [Results] After the stretching exercises of the upper trapezius, the results showed that for the first group, whose asymmetric rate of biting force was less than 10%, there was a significant increase in asymmetric rate (from 5.1% to 10.3%). For the second group, whose asymmetric rate of biting force was measured to be between 10% and 20%, the asymmetric rate decreased from 14.7% to 14.3%, but the change was not statistically significant. For the third group, whose asymmetric rate of biting force was more than 20%, there was a significant decrease in asymmetric rate (from 27.8% to 12.6%). [Conclusion] We concluded that stretching exercises of the upper trapezius muscle had a direct effect on the asymmetric rate of biting force.

  2. Fast and Powerful: Biomechanics and Bite Forces of the Mandibles in the American Cockroach Periplaneta americana.

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    Tom Weihmann

    Full Text Available Knowing the functionality and capabilities of masticatory apparatuses is essential for the ecological classification of jawed organisms. Nevertheless insects, especially with their outstanding high species number providing an overwhelming morphological diversity, are notoriously underexplored with respect to maximum bite forces and their dependency on the mandible opening angles. Aiming for a general understanding of insect biting, we examined the generalist feeding cockroach Periplaneta americana, characterized by its primitive chewing mouth parts. We measured active isometric bite forces and passive forces caused by joint resistance over the entire mandibular range with a custom-built 2D force transducer. The opening angle of the mandibles was quantified by using a video system. With respect to the effective mechanical advantage of the mandibles and the cross-section areas, we calculated the forces exerted by the mandible closer muscles and the corresponding muscle stress values. Comparisons with the scarce data available revealed close similarities of the cockroaches' mandible closer stress values (58 N/cm2 to that of smaller specialist carnivorous ground beetles, but strikingly higher values than in larger stag beetles. In contrast to available datasets our results imply the activity of faster and slower muscle fibres, with the latter becoming active only when the animals chew on tough material which requires repetitive, hard biting. Under such circumstances the coactivity of fast and slow fibres provides a force boost which is not available during short-term activities, since long latencies prevent a specific effective employment of the slow fibres in this case.

  3. Chewing side, bite force symmetry, and occlusal contact area of subjects with different facial vertical patterns

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    Simone Guimarães Farias Gomes

    2011-10-01

    Full Text Available Craniofacial dimensions influence oral functions; however, it is not known whether they are associated with function asymmetry. The objective of this study was to evaluate chewing side preference and lateral asymmetry of occlusal contact area and bite force of individuals with different craniofacial patterns. Seventy-eight dentate subjects were divided into 3 groups according to the VERT index as follows: (1 mesofacial, (2 brachyfacial and (3 dolichofacial. Chewing side preference was evaluated using jaw tracking equipment, occlusal contact area was measured by silicon registration of posterior teeth, and bite force was measured unilaterally on molar regions using 2.25 mm-thick sensors. Statistical analysis was performed using ANOVA on Ranks, Student's t-test, and Mann-Whitney tests at a 5% significance level. Mesofacial, brachyfacial, and dolichofacial subjects presented more occlusal contact area on the left side. Only dolichofacial subjects showed lateral asymmetry for bite force, presenting higher force on the left side. No statistically significant differences were found for chewing side preference among all groups. Within the limitations of this study, it can be concluded that craniofacial dimensions play a role in asymmetry of bite force. ClinicalTrials.gov ID: NCT01286363.

  4. Effect of bite force and diet composition on craniofacial diversification of Southern South American human populations.

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    Menéndez, Lumila; Bernal, Valeria; Novellino, Paula; Perez, S Ivan

    2014-09-01

    Ecological factors can be important to shape the patterns of morphological variation among human populations. Particularly, diet plays a fundamental role in craniofacial variation due to both the effect of the nutritional status-mostly dependent on the type and amount of nutrients consumed-on skeletal growth and the localized effects of masticatory forces. We examine these two dimensions of diet and evaluate their influence on morphological diversification of human populations from southern South America during the late Holocene. Cranial morphology was measured as 3D coordinates defining the face, base and vault. Size, form, and shape variables were obtained for 474 adult individuals coming from 12 samples. Diet composition was inferred from carious lesions and δ(13) C data, whereas bite forces were estimated using traits of main jaw muscles. The spatial structure of the morphological and ecological variables was measured using correlograms. The influence of diet composition and bite force on morphometric variation was estimated by a spatial regression model. Cranial variation and diet composition display a geographical structure, while no geographical pattern was observed in bite forces. Cranial variation in size and form is significantly associated with diet composition, suggesting a strong effect of systemic factors on cranial growth. Conversely, bite forces do not contribute significantly to the pattern of morphological variation among the samples analyzed. Overall, these results show that an association between diet composition and hardness cannot be assumed, and highlight the complex relationship between morphological diversification and diet in human populations. Copyright © 2014 Wiley Periodicals, Inc.

  5. Relationship between orofacial function, dentofacial morphology, and bite force in young subjects.

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    Marquezin, M C S; Gavião, M B D; Alonso, M B C C; Ramirez-Sotelo, L R; Haiter-Neto, F; Castelo, P M

    2014-09-01

    The aim was to evaluate the relationship between orofacial function, dentofacial morphology, and bite force in young subjects. Three hundred and sixteen subjects were divided according to dentition stage (early, intermediate, and late mixed and permanent dentition). Orofacial function was screened using the Nordic Orofacial Test-Screening (NOT-S). Orthodontic treatment need, bite force, lateral and frontal craniofacial dimensions and presence of sleep bruxism were also assessed. The results were submitted to descriptive statistics, normality and correlation tests, analysis of variance, and multiple linear regression to test the relationship between NOT-S scores and the studied independent variables. The variance of NOT-S scores between groups was not significant. The evaluation of the variables that significantly contributed to NOT-S scores variation showed that age and presence of bruxism related to higher NOT-S total scores, while the increase in overbite measurement and presence of closed lip posture related to lower scores. Bite force did not show a significant relationship with scores of orofacial dysfunction. No significant correlations between craniofacial dimensions and NOT-S scores were observed. Age and sleep bruxism were related to higher NOT-S scores, while the increase in overbite measurement and closed lip posture contributed to lower scores of orofacial dysfunction. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Novel System for Bite-Force Sensing and Monitoring Based on Magnetic Near Field Communication

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    Jesús Sanz Maudes

    2012-08-01

    Full Text Available Intraoral devices for bite-force sensing have several applications in odontology and maxillofacial surgery, as bite-force measurements provide additional information to help understand the characteristics of bruxism disorders and can also be of help for the evaluation of post-surgical evolution and for comparison of alternative treatments. A new system for measuring human bite forces is proposed in this work. This system has future applications for the monitoring of bruxism events and as a complement for its conventional diagnosis. Bruxism is a pathology consisting of grinding or tight clenching of the upper and lower teeth, which leads to several problems such as lesions to the teeth, headaches, orofacial pain and important disorders of the temporomandibular joint. The prototype uses a magnetic field communication scheme similar to low-frequency radio frequency identification (RFID technology (NFC. The reader generates a low-frequency magnetic field that is used as the information carrier and powers the sensor. The system is notable because it uses an intra-mouth passive sensor and an external interrogator, which remotely records and processes information regarding a patient’s dental activity. This permits a quantitative assessment of bite-force, without requiring intra-mouth batteries, and can provide supplementary information to polysomnographic recordings, current most adequate early diagnostic method, so as to initiate corrective actions before irreversible dental wear appears. In addition to describing the system’s operational principles and the manufacture of personalized prototypes, this report will also demonstrate the feasibility of the system and results from the first in vitro and in vivo trials.

  7. Change in bite force and electromyographic activity of masticatory muscle in accordance with change of occlusal plane.

    Science.gov (United States)

    Park, Min-Kyu; Cho, Sung-Min; Yun, Kyoung-In; Park, Je-Uk

    2012-08-01

    The purpose of the present study was to evaluate effects of occlusal plane on masticatory function (biting force, masticatory muscle activity, biting efficiency) after bimaxillary orthognathic surgery. The subjects of the present study consisted of a group of 55 adults who had undergone bimaxillary surgery more than 6 months earlier. Lateral cephalographs, bite force, and electromyographic measurements of the anterior temporal [EMG(t)] and masseter muscles [EMG(m)] were recorded before and after bimaxillary surgery. Statistical analyses were performed. In the increased occlusal plane group, the frequency of decreased EMG(t) was significantly high. The frequency of increased EMG(t) was also significantly high in the decreased occlusal plane group. A negative correlation was found between the postoperative occlusal plane angle and the biting force efficiency change. No significant difference was found between the group that moved from an abnormal to a normal range and the group that moved from a normal to an abnormal range. The occlusal plane change was significantly greater in the decreased EMG(t) group than in the increased EMG(t) group. The value of EMG(t) was related to the changes in the occlusal plane, and the biting efficiency was affected by the postoperative occlusal plane angle. However, normalization of the occlusal plane might not play a major role in masticatory function. Copyright © 2012 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  8. Postural And Eye-Positional Effects On Human Biting Force: An Experimental Study

    Directory of Open Access Journals (Sweden)

    Altay Tabancacı

    2012-06-01

    Full Text Available Muscle groups affected on biting force are called temporal muscle as a major and masseter muscle as a minor. According to the human posture stability, forces of these muscles vary with the force directions. In this case, experimental investigation is strictly important such that biting force under different postural and eye- positional situations is changed. In this study, seven-male and seven-female within the age-range of 17-24 are considered corresponding to having with restorated molar tooth and without that type of tooth. With the help of specially designed biting fork, different posture- and eye-positions are investigated for experimental biting force analysis. Changes in eye-positions are not indicated significant difference for all postural positions. On one hand, it is obtained that biting force of no-filling tooth in men becomes maximum if facial muscles give full effort to biting. On the other hand, effect of facial muscles for women is not clearly noticed depending on the postural differences.

  9. Bite frequency measured by head pitch movements in grazing experiment

    DEFF Research Database (Denmark)

    Oudshoorn, Frank W.; S. Nadimi, Esmaeil; Jørgensen, Rasmus Nyholm

    2010-01-01

    sensors placed on the head of the cows, bite frequency was registered manually by noting the rip off sound during a specified time bout. Sward registrations comprised grass length measurement by rising plate meter , grass quality by laboratory analysis of hand harvested grass simulating the cows grazing...

  10. Pattern of First-Aid Measures Used by Snake-bite Patients and ...

    African Journals Online (AJOL)

    The use of first aid measures in the management of snake bite by patients in rural communities in Africa is a popular practice. Records of 103 snake bite patients admitted at Zamko Comprehensive Health Centre, were retrieved and reviewed. 84 (81.6%) of the 103 cases with snake bite used first aid measures. Common first ...

  11. The effect of maximum bite force on marginal bone loss in mandibular overdenture treatment : an in vivo study

    NARCIS (Netherlands)

    van Kampen, F; Cune, M; van der Bilt, A; Bosman, F

    2005-01-01

    The impact of bite force on the marginal bone response around implants is a subject of debate. This study focused on the effect of maximum bite force on marginal bone levels in mandibular implant overdenture treatment. In addition, the effect of the sequence of 3 different loading conditions on

  12. Facial dimensions, bite force and masticatory muscle thickness in preschool children with functional posterior crossbite

    Directory of Open Access Journals (Sweden)

    Paula Midori Castelo

    2008-03-01

    Full Text Available Posterior crossbite may affect craniofacial growth and development. Thus, this study aimed to associate facial dimensions (by standardized frontal photographs to masseter and anterior portion of the temporal muscle thickness (by ultrasonography and maximal bilateral bite force in 49 children with deciduous and early mixed dentitions. They were distributed in four groups: deciduous-normal occlusion (DNO, n = 15, deciduous-crossbite (DCB, n = 10, mixed-normal occlusion (MNO, n = 13 and mixed-crossbite (MCB, n = 11. Anterior facial height (AFH, bizygomatic width (FWB, and intergonial width (FWI were determined and associated with muscle thickness and bite force, applying Pearson’s coefficients and multiple logistic regression, with age, gender, body weight and height as the covariates. FWB and FWI were correlated positively with the masseter thickness, whereas AFH/FWB and AFH/FWI ratios had negative correlation, except in the DNO group. The correlation between AFH/FWB and bite force in the MCB group was significantly negative. A higher AFH/FWB in MNO and MCB led to a significantly higher probability for functional crossbite development. In the studied sample, it was observed that children in the early mixed dentition with a long-face trend showed lower bite force and higher probability to present functional posterior crossbite, without significant influence of the covariates.

  13. Relationship between oral status and maximum bite force in preschool children

    Directory of Open Access Journals (Sweden)

    Ching-Ming Su

    2009-03-01

    Conclusion: By combining the results of this study, it was concluded that associations of bite force with factors like age, maximum mouth opening and the number of teeth in contact were clearer than for other variables such as body height, body weight, occlusal pattern, and tooth decay or fillings.

  14. Visual Feedback of Bilateral Bite Force to Assess Motor Control of the Mandible in Isometric Condition.

    Science.gov (United States)

    Testa, Marco; Geri, Tommaso; Signori, Alessio; Roatta, Silvestro

    2015-10-01

    The assessment of the individual ability of modulating and coordinating the right and left bite force is poorly investigated. The present study describes a methodology for the assessment of the bilateral control of the biting force and evaluates the test-retest reliability in a sample of 13 healthy subjects. By modulating the intensity and the left/right balance of the biting force, the subject was able to drive a cursor on the screen to "reach and hold" targets, randomly generated within the physiological "range of force" of the subject. The average motor performance was evaluated by the mean cursor-target distance = 13 ± 5%, the Offset Error = 9 ± 5% and the standard deviation of the force vector = 17.7 ± 6.1% (expressed as % of the target). Mean distance and standard deviation indices had acceptable reliability. This technique improves the characterization of the mandibular motor function and it may have a relevant role for the assessment and rehabilitation of the neuromusculoskeletal disorders affecting the orofacial system.

  15. Occlusal bite force change after orthodontic treatment with Andresen functional appliance.

    Science.gov (United States)

    Al-Khateeb, Susan N; Abu Alhaija, Elham S; Majzoub, Sami

    2015-04-01

    The aim of this study was to determine the occlusal bite force (OBF) changes, at the incisal and molar regions, after orthodontic treatment with functional appliance therapy in preadolescent subjects. OBF was measured for patients (17 females and 16 males) before and after the treatment with Andresen functional appliance for an average period of 9 months (mean age was 11.8±1.1 years). Three variables were registered; maximum OBF at molar region and the average of three readings at the molar (AOBF) and incisal regions (IOBF). The same variables were measured in two occasions for a matching non-treated control group with a period of 9 months between the two measurements. No significant changes were seen in the OBF measured parameters in the control group. There was a reduction in all measured parameters. The mean reduction in maximum OBF was 76.1±12.4 N (P appliance caused a significant reduction in OBF immediately after treatment. © The Author 2014. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  16. Forças de mordida relacionadas a próteses parciais removíveis inferiores Biting forces related to partially removable mandibular dentures

    Directory of Open Access Journals (Sweden)

    Eduardo Piza PELLIZZER

    1998-10-01

    Full Text Available A pesquisa teve como objetivo determinar as forças de mordida de 73 indivíduos, por meio de um gnatodinamômetro. Os pacientes eram portadores de próteses parciais removíveis inferiores classes I, II ou III. A arcada antagonista era prótese, parcial removível ou fixa, ou total. Os resultados permitiram concluir que: as selas de extremidade livre, principalmente em suas posições extremas, conduziram a forças de mordida muito baixas; o envolvimento de prótese total, também, conduziu a forças de mordida baixas; o sexo masculino alcançou valores maiores que o feminino; com prótese parcial removível classe III, os dentes naturais molares e pré-molares desenvolveram valores maiores do que com classes I e II.The purpose of this study was to determine the biting forces of individuals wearing classes I, II or III partially removable mandibular dentures. Upper jaws presented fixed bridges, classes I, II or III partially removable dentures, or complete dentures. Measurements of biting forces were obtained by a gnathodynamometer. The conclusions were: classes I and II presented low biting forces, specially far from the last abutment tooth; when the opposite arcade was a complete denture, biting forces were low; males presented higher biting forces than females; natural molars and bicuspids presented higher biting forces with class III than with classes I or II.

  17. Morphometry, Bite-Force, and Paleobiology of the Late Miocene Caiman Purussaurus brasiliensis

    OpenAIRE

    Aureliano, Tito; Ghilardi, Aline M.; Guilherme, Edson; Souza-Filho, Jonas P.; Cavalcanti, Mauro; Riff, Douglas

    2015-01-01

    Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimat...

  18. The relationship between skull morphology, masticatory muscle force and cranial skeletal deformation during biting.

    Science.gov (United States)

    Toro-Ibacache, Viviana; Zapata Muñoz, Víctor; O'Higgins, Paul

    2016-01-01

    The human skull is gracile when compared to many Middle Pleistocene hominins. It has been argued that it is less able to generate and withstand high masticatory forces, and that the morphology of the lower portion of the modern human face correlates most strongly with dietary characteristics. This study uses geometric morphometrics and finite element analysis (FEA) to assess the relationship between skull morphology, muscle force and cranial deformations arising from biting, which is relevant in understanding how skull morphology relates to mastication. The three-dimensional skull anatomies of 20 individuals were reconstructed from medical computed tomograms. Maximal contractile muscle forces were estimated from muscular anatomical cross-sectional areas (CSAs). Fifty-nine landmarks were used to represent skull morphology. A partial least squares analysis was performed to assess the association between skull shape and muscle force, and FEA was used to compare the deformation (strains) generated during incisor and molar bites in two individuals representing extremes of morphological variation in the sample. The results showed that only the proportion of total muscle CSA accounted for by the temporalis appears associated with skull morphology, albeit weekly. However, individuals with a large temporalis tend to possess a relatively wider face, a narrower, more vertically oriented maxilla and a lower positioning of the coronoid process. The FEAs showed that, despite differences in morphology, biting results in similar modes of deformation for both crania, but with localised lower magnitudes of strains arising in the individual with the narrowest, most vertically oriented maxilla. Our results suggest that the morphology of the maxilla modulates the transmission of forces generated during mastication to the rest of the cranium by deforming less in individuals with the ability to generate proportionately larger temporalis muscle forces. Copyright © 2015 Elsevier GmbH. All

  19. The effect of different attachment systems with implant-retained overdentures on maximum bite force and EMG.

    Science.gov (United States)

    Uçankale, Mert; Akoğlu, Burçin; Ozkan, Yaşar; Ozkan, Yasemin Kulak

    2012-03-01

    To compare the effect of different attachment systems with implant-retained overdentures on maximum bite force and muscle activity using electromyography (EMG). Denture retention and stability is of considerable interest in prosthetic dentistry. Thirty-five patients were examined: 15 edentulous patients treated with mandibular implant-retained overdentures (MIRO) and maxillary dentures (MCD) (two implant-ball attachment) (BC); 10 edentulous patients treated with MIRO and MCD (four implants-bar attachments) (BRC); 10 patients with edentulous mandibular treated with MIRO and maxillary fixed partial dentures (MFPD) (two implant-ball attachments) (BF). Before implant placement all patients received new dentures. After using these dentures for 3 months the maximum bite force and electrical activity of masseter muscle were measured. Two or four implants were then inserted into the intraforaminal region. After osseointegration periods, patients were treated with MIRO which duplicated their dentures and after three months the measurements were repeated. The data were collected and statistically analysed. Muscle activity and chewing ability increased in the second period of measurements. Also chewing time was significantly decreased at the first measurements. The highest muscle activity was observed in the group of patients treated with group BF. The EMG values of the masseter muscle significantly increased when an implant attachments was used in the overdenture. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  20. Effect of telescopic distal extension removable partial dentures on oral health related quality of life and maximum bite force: A preliminary cross over study.

    Science.gov (United States)

    Elsyad, Moustafa Abdou; Mostafa, Aisha Zakaria

    2018-01-01

    This cross over study aimed to evaluate the effect of telescopic distal extension removable partial dentures on oral health related quality of life and maximum bite force MATERIALS AND METHODS: Twenty patients with complete maxillary edentulism and partially edentulous mandibles with anterior teeth only remaining were selected for this cross over study. All patients received complete maxillary dentures and mandibular partial removable dental prosthesis (PRDP, control). After 3 months of adaptation, PRDP was replaced with conventional telescopic partial dentures (TPD) or telescopic partial dentures with cantilevered extensions (TCPD) in a quasi-random method. Oral health related quality of life (OHRQoL) was measured using OHIP-14 questionnaire and Maximum bite force (MBF) was measured using a bite force transducer. Measurements were performed 3 months after using each of the following prostheses; PRDP, TPD, and TCPD. TCPD showed the OHIP-14 lowest scores (i.e., the highest patient satisfaction with their OHRQoL), followed by TPD, and PRDP showed the highest OHIP-14 scores (i.e., the lowest patient satisfaction with OHRQoL). TCPD showed the highest MBF (70.7 ± 3.71), followed by TPD (57.4 ± 3.43) and the lowest MBF (40.2 ± 2.20) was noted with PRDP. WITHIN The Limitations of This Study, Mandibular Telescopic Distal Extension Removable Partial Dentures with Cantilevered Extensions Were Associated with Improved Oral Health Related Quality of Life and Maximum Bite Force Compared to Telescopic or Conventional PRDP. Telescopic distal extension removable prostheses is an esthetic restoration in partially edentulous patients with free end saddle. This article describes the addition of cantilevered extensions of this prosthesis. The results showed that telescopic distal extension removable prostheses with cantilevered extensions were associated with improved oral health related quality of life and maximum bite force compared to telescopic or conventional RPDs

  1. Chewing efficiency and maximum bite force with different attachment systems of implant overdentures: a crossover study.

    Science.gov (United States)

    Elsyad, Moustafa Abdou; Khairallah, Ahmed Samir

    2017-06-01

    This crossover study aimed to evaluate and compare chewing efficiency and maximum bite force (MBF) with resilient telescopic and bar attachment systems of implant overdentures in patients with atrophied mandibles. Ten participants with severely resorbed mandibles and persistent denture problems received new maxillary and mandibular conventional dentures (control, CD). After 3 months of adaptation, two implants were inserted in canine region of the mandible. In a quasi-random method, overdentures were connected to the implants with either bar overdentures (BOD) or resilient telescopic overdentures (TOD) attachment systems. Chewing efficiency in terms of unmixed fraction (UF) was measured using chewing gum (after 5, 10, 20, 30 and 50 strokes), and MBF was measured using a bite force transducer. Measurements were performed 3 months after using each of the following prostheses: CD, BOD and TOD. Chewing efficiency and MBF increased significantly with BOD and TOD compared to CD. As the number of chewing cycles increased, the UF decreased. TOD recorded significant higher chewing efficiency and MBF than BOD. Resilient telescopic attachments are associated with increased chewing efficiency and MBF compared bar attachments when used to retain overdentures to the implants in patients with atrophied mandibles. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Individual variations in numerically modeled human muscle and temporomandibular joint forces during static biting.

    Science.gov (United States)

    Iwasaki, Laura R; Thornton, Benjamin R; McCall, Willard D; Nickel, Jeffrey C

    2004-01-01

    To test the effects of occlusal force (OF) angle on the variations in predicted muscle and temporomandibular joint (TMJ) forces during unilateral molar bites. The craniomandibular (CM) geometries of 21 individuals were determined from lateral and posteroanterior cephalometric radiographs. These geometries were used in a numerical model based on minimization of muscle effort. This model was previously validated for this subject group through the use of jaw tracking and electromyographic data. The model predicted muscle and TMJ forces associated with static OFs on the right mandibular first molar. OF angle was varied from vertical to 40 degrees in the buccal and lingual directions, in increments of 10 degrees. Intra- and intersubject variations in predicted muscle and TMJ forces for unilateral molar biting were dependent on OF angle and CM geometry. Nonvertical OFs were associated with either large anterior temporalis muscle forces (> 100% of applied OF in 3 subjects) or large inferior lateral pterygoid muscle forces (> 90% of applied OF in 3 subjects). On average, vertically and buccally directed OFs were associated with higher mean contralateral TMJ forces (60% of applied OF, SD 12%). Two subjects had large ipsilateral or contralateral TMJ forces (> 90% of applied OF). In a group of healthy subjects, depending on the individual CM geometry, large muscle and/or TMJ forces were predicted to be associated with specific unilateral molar OF angles. Propensities to increased muscle or joint forces may be predisposing factors in the development of myofascial pain or intracapsular disease. The results may explain, in part, the variation in location of symptoms in individuals who first present with temporomandibular disorders.

  3. Morphometry, Bite-Force, and Paleobiology of the Late Miocene Caiman Purussaurus brasiliensis

    Science.gov (United States)

    Aureliano, Tito; Ghilardi, Aline M.; Guilherme, Edson; Souza-Filho, Jonas P.; Cavalcanti, Mauro; Riff, Douglas

    2015-01-01

    Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force). The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts. PMID:25689140

  4. Morphometry, bite-force, and paleobiology of the late miocene caiman Purussaurus brasiliensis.

    Directory of Open Access Journals (Sweden)

    Tito Aureliano

    Full Text Available Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force. The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts.

  5. Morphometry, bite-force, and paleobiology of the late miocene caiman Purussaurus brasiliensis.

    Science.gov (United States)

    Aureliano, Tito; Ghilardi, Aline M; Guilherme, Edson; Souza-Filho, Jonas P; Cavalcanti, Mauro; Riff, Douglas

    2015-01-01

    Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force). The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts.

  6. Bone-breaking bite force of Basilosaurus isis (Mammalia, Cetacea from the late Eocene of Egypt estimated by finite element analysis.

    Directory of Open Access Journals (Sweden)

    Eric Snively

    Full Text Available Bite marks suggest that the late Eocence archaeocete whale Basilosaurus isis (Birket Qarun Formation, Egypt fed upon juveniles of the contemporary basilosaurid Dorudon atrox. Finite element analysis (FEA of a nearly complete adult cranium of B. isis enables estimates of its bite force and tests the animal's capabilities for crushing bone. Two loadcases reflect different biting scenarios: 1 an intitial closing phase, with all adductors active and a full condylar reaction force; and 2 a shearing phase, with the posterior temporalis active and minimized condylar force. The latter is considered probable when the jaws were nearly closed because the preserved jaws do not articulate as the molariform teeth come into occulusion. Reaction forces with all muscles active indicate that B. isis maintained relatively greater bite force anteriorly than seen in large crocodilians, and exerted a maximum bite force of at least 16,400 N at its upper P3. Under the shearing scenario with minimized condylar forces, tooth reaction forces could exceed 20,000 N despite lower magnitudes of muscle force. These bite forces at the teeth are consistent with bone indentations on Dorudon crania, reatract-and-shear hypotheses of Basilosaurus bite function, and seizure of prey by anterior teeth as proposed for other archaeocetes. The whale's bite forces match those estimated for pliosaurus when skull lengths are equalized, suggesting similar tradeoffs of bite function and hydrodynamics. Reaction forces in B. isis were lower than maxima estimated for large crocodylians and carnivorous dinosaurs. However, comparison of force estimates from FEA and regression data indicate that B. isis exerted the largest bite forces yet estimated for any mammal, and greater force than expected from its skull width. Cephalic feeding biomechanics of Basilosaurus isis are thus consistent with habitual predation.

  7. Mandibular kinematics and maximum voluntary bite force following segmental resection of the mandible without or with reconstruction.

    Science.gov (United States)

    Linsen, Sabine S; Oikonomou, Annina; Martini, Markus; Teschke, Marcus

    2018-05-01

    The purpose was to analyze mandibular kinematics and maximum voluntary bite force in patients following segmental resection of the mandible without and with reconstruction (autologous bone, alloplastic total temporomandibular joint replacement (TMJ TJR)). Subjects operated from April 2002 to August 2014 were enrolled in the study. Condylar (CRoM) and incisal (InRoM) range of motion and deflection during opening, condylar retrusion, incisal lateral excursion, mandibular rotation angle during opening, and maximum voluntary bite force were determined on the non-affected site and compared between groups. Influence of co-factors (defect size, soft tissue deficit, neck dissection, radiotherapy, occlusal contact zones (OCZ), and time) was determined. Twelve non-reconstructed and 26 reconstructed patients (13 autologous, 13 TMJ TJR) were included in the study. InRoM opening and bite force were significantly higher (P ≤ .024), and both condylar and incisal deflection during opening significantly lower (P ≤ .027) in reconstructed patients compared with non-reconstructed. Differences between the autologous and the TMJ TJR group were statistically not significant. Co-factors defect size, soft tissue deficit, and neck dissection had the greatest impact on kinematics and number of OCZs on bite force. Reconstructed patients (both autologous and TMJ TJR) have better overall function than non-reconstructed patients. Reconstruction of segmental mandibular resection has positive effects on mandibular function. TMJ TJR seems to be a suitable technique for the reconstruction of mandibular defects including the TMJ complex.

  8. [Can magnets or additional intermaxillary forces improve the mode of action of jumping-the-bite plates?].

    Science.gov (United States)

    Sander, F G; Wichelhaus, A

    1994-12-01

    The use of accessory intermaxillary elastic traction or magnets during bite jumping appliance therapy marks a significant improvement in patient treatment. The use of interarch traction results in 100% mouth closure during the night, which is independent of the patient's sleeping position. During the night the guide pegs are subjected to almost no stress, which guarantees a quick adaptation. Additional intermaxillary traction does call for anchoring procedures in the maxillary anterior (torque springs) and mandibular molar region (clasps). According to the dental situation, the application of dynamic force can be withdrawn for a transitory period of time. Use of additional magnets in the anterior, depending on sleeping position, leads to complete mouth closure in up to 70 to 90% of the cases. Extensive measures in the mandibular and maxillary anterior areas must be considered when using this variant. In many cases the application of brackets is an absolute necessity. However, when the dental situation calls for it, magnets cannot be deactivated. All magnets in use today corrode very easily. It is, therefore, recommended that magnets used interorally be especially well shielded. Leaky capsules must considered especially problematic. Correct adjustment in the sagittal plane does not in any case guarantee stabilization. Only when a 3- or 4-stage bite has been reached, can it be said that a good adjustment in the neuromuscular masticatory pattern has been achieved. Depending on patient compliance, this period can be significantly drawn out. A functional analysis is not a suitable method for analyzing an extant stable result. With both of these modifications there is a tendency to greater dentoalveolar effect and diminished influence on the skull. The issue of whether magnets have no place in orthodontics, as Gianelly [3] claims, cannot be definitively answered, however, it can be said that intermaxillary traction, especially when force is applied by using super

  9. Interfacial force measurements using atomic force microscopy

    NARCIS (Netherlands)

    Chu, L.

    2018-01-01

    Atomic Force Microscopy (AFM) can not only image the topography of surfaces at atomic resolution, but can also measure accurately the different interaction forces, like repulsive, adhesive and lateral existing between an AFM tip and the sample surface. Based on AFM, various extended techniques have

  10. Tooth eruption results from bone remodelling driven by bite forces sensed by soft tissue dental follicles: a finite element analysis.

    Science.gov (United States)

    Sarrafpour, Babak; Swain, Michael; Li, Qing; Zoellner, Hans

    2013-01-01

    Intermittent tongue, lip and cheek forces influence precise tooth position, so we here examine the possibility that tissue remodelling driven by functional bite-force-induced jaw-strain accounts for tooth eruption. Notably, although a separate true 'eruptive force' is widely assumed, there is little direct evidence for such a force. We constructed a three dimensional finite element model from axial computerized tomography of an 8 year old child mandible containing 12 erupted and 8 unerupted teeth. Tissues modelled included: cortical bone, cancellous bone, soft tissue dental follicle, periodontal ligament, enamel, dentine, pulp and articular cartilage. Strain and hydrostatic stress during incisive and unilateral molar bite force were modelled, with force applied via medial and lateral pterygoid, temporalis, masseter and digastric muscles. Strain was maximal in the soft tissue follicle as opposed to surrounding bone, consistent with follicle as an effective mechanosensor. Initial numerical analysis of dental follicle soft tissue overlying crowns and beneath the roots of unerupted teeth was of volume and hydrostatic stress. To numerically evaluate biological significance of differing hydrostatic stress levels normalized for variable finite element volume, 'biological response units' in Nmm were defined and calculated by multiplication of hydrostatic stress and volume for each finite element. Graphical representations revealed similar overall responses for individual teeth regardless if incisive or right molar bite force was studied. There was general compression in the soft tissues over crowns of most unerupted teeth, and general tension in the soft tissues beneath roots. Not conforming to this pattern were the unerupted second molars, which do not erupt at this developmental stage. Data support a new hypothesis for tooth eruption, in which the follicular soft tissues detect bite-force-induced bone-strain, and direct bone remodelling at the inner surface of the

  11. Preparing the Periphery for a Subsequent Behavior: Motor Neuronal Activity during Biting Generates Little Force but Prepares a Retractor Muscle to Generate Larger Forces during Swallowing in Aplysia

    Science.gov (United States)

    Lu, Hui; McManus, Jeffrey M.; Cullins, Miranda J.

    2015-01-01

    Some behaviors occur in obligatory sequence, such as reaching before grasping an object. Can the earlier behavior serve to prepare the musculature for the later behavior? If it does, what is the underlying neural mechanism of the preparation? To address this question, we examined two feeding behaviors in the marine mollusk Aplysia californica, one of which must precede the second: biting and swallowing. Biting is an attempt to grasp food. When that attempt is successful, the animal immediately switches to swallowing to ingest food. The main muscle responsible for pulling food into the buccal cavity during swallowing is the I3 muscle, whose motor neurons B6, B9, and B3 have been previously identified. By performing recordings from these neurons in vivo in intact, behaving animals or in vitro in a suspended buccal mass preparation, we demonstrated that the frequencies and durations of these motor neurons increased from biting to swallowing. Using the physiological patterns of activation to drive these neurons intracellularly, we further demonstrated that activating them using biting-like frequencies and durations, either alone or in combination, generated little or no force in the I3 muscle. When biting-like patterns preceded swallowing-like patterns, however, the forces during the subsequent swallowing-like patterns were significantly enhanced. Sequences of swallowing-like patterns, either with these neurons alone or in combination, further enhanced forces in the I3 muscle. These results suggest a novel mechanism for enhancing force production in a muscle, and may be relevant to understanding motor control in vertebrates. PMID:25810534

  12. The influence of implant number and attachment type on maximum bite force of mandibular overdentures: a retrospective study.

    Science.gov (United States)

    Bilhan, Hakan; Geckili, Onur; Mumcu, Emre; Cilingir, Altug; Bozdag, Ergun

    2012-06-01

    Assessment of the influence of such factors as attachment type, number of implants, gender and age of patients on maximum bite force (MBF). Sixty-two edentulous patients (32 females, 30 males; aged 64.03 ± 10.07 years, range 42-90 years) with mandibular implant overdentures with various attachment types were included in the study and their MBFs were recorded. The results were evaluated statistically at a significance level of p 0.05) were found with respect to age groups, attachment types and number of implants supporting the mandibular overdentures. Within the limitations of this study, it is concluded that independent of the number applied, dental implants increase MBF in edentulous patients. While males show higher bite force, patient age and attachment type seem not to play an important role. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  13. Intraoral conversion of occlusal force to electricity and magnetism by biting of piezoelectric elements.

    Science.gov (United States)

    Kameda, Takashi; Ohkuma, Kazuo; Sano, Natsuki; Ogura, Hideo; Terada, Kazuto

    2012-01-01

    Very weak electrical, magnetic and ultrasound signal stimulations are known to promote the formation, metabolism, restoration and stability of bone and surrounding tissues after treatment and operations. We have therefore investigated the possibility of intraoral generation of electricity and magnetism by occlusal force in an in vitro study. Biting bimorph piezoelectric elements with lead zirconate titanate (PZT) using dental models generated appropriate magnetism for bone formation, i. e. 0.5-0.6 gauss, and lower electric currents and higher voltages, i. e. 2.0-6.0 μA at 10-22 V (appropriate levels are 30 μA and 1.25 V), as observed by a universal testing machine. The electric currents and voltages could be changed using amplifier circuits. These results show that intraoral generation of electricity and magnetism is possible and could provide post-operative stabilization and activation of treated areas of bone and the surrounding tissues directly and/or indirectly by electrical, magnetic and ultrasound stimulation, which could accelerate healing.

  14. Effects of gape and tooth position on bite force and skull stress in the dingo (Canis lupus dingo using a 3-dimensional finite element approach.

    Directory of Open Access Journals (Sweden)

    Jason Bourke

    Full Text Available Models of the mammalian jaw have predicted that bite force is intimately linked to jaw gape and to tooth position. Despite widespread use, few empirical studies have provided evidence to validate these models in non-human mammals and none have considered the influence of gape angle on the distribution of stress. Here using a multi-property finite element (FE model of Canis lupus dingo, we examined the influence of gape angle and bite point on both bite force and cranial stress. Bite force data in relation to jaw gape and along the tooth row, are in broad agreement with previously reported results. However stress data showed that the skull of C. l. dingo is mechanically suited to withstand stresses at wide gapes; a result that agreed well with previously held views regarding carnivoran evolution. Stress data, combined with bite force information, suggested that there is an optimal bite angle of between 25 degrees and 35 degrees in C. l. dingo. The function of these rather small bite angles remains unclear.

  15. Implant-tooth-supported fixed partial prostheses: correlations between in vivo occlusal bite forces and marginal bone reactions.

    Science.gov (United States)

    Akça, Kivanç; Uysal, Serdar; Cehreli, Murat Cavit

    2006-06-01

    To evaluate maximal occlusal bite forces (MOF) and marginal bone level (MBL) changes in patients with implant-tooth-supported fixed partial prostheses (FPP). Twenty nine partially edentulous patients consecutively who received 34 three-occlusal unit FPP with terminal implant and tooth support were subjected to quantification of MOFs using a sub-miniature load cell connected to a data acquisition system and measurement of the MBL changes around implants in digitalized periapical radiographs obtained at prostheses delivery and 24-month follow-up. MOFs for implant support (mean: 353.61 N) significantly differed from tooth support (mean: 275.48 N) (P 0.05). MBL changes at mesial and distal sites of the implants at 24 months of functional loading were 0.28 and 0.097 mm respectively. Although MOFs under functional loading might indicate an increase in load participation for supporting implant, the rigid connection between implant and natural tooth via three-occlusal unit FPP does not jeopardize the time-dependent MBL stability of the implant under functional loads.

  16. Influence of sustained submaximal clenching fatigue test on electromyographic activity and maximum voluntary bite forces in healthy subjects and patients with temporomandibular disorders.

    Science.gov (United States)

    Xu, L; Fan, S; Cai, B; Fang, Z; Jiang, X

    2017-05-01

    This study aimed to investigate whether the fatigue induced by sustained motor task in the jaw elevator muscles differed between healthy subjects and patients with temporomandibular disorder (TMD). Fifteen patients with TMD and thirteen age- and sex-matched healthy controls performed a fatigue test consisting of sustained clenching contractions at 30% maximal voluntary clenching intensity until test failure (the criterion for terminating the fatigue test was when the biting force decreased by 10% or more from the target force consecutively for >3 s). The pre- and post-maximal bite forces (MBFs) were measured. Surface electromyographic signals were recorded from the superficial masseter muscles and anterior temporal muscles bilaterally, and the median frequency at the beginning, middle and end of the fatigue test was calculated. The duration of the fatigue test was also quantified. Both pre- and post-MBFs were lower in patients with TMD than in controls (P fatigue test in TMD patients was significantly shorter than that of the controls (P fatigued, but the electromyographic activation process during the fatigue test is similar between healthy subjects and patients with TMD. However, the mechanisms involved in this process remain unclear, and further research is warranted. © 2017 John Wiley & Sons Ltd.

  17. The effect of maximum bite force, implant number, and attachment type on marginal bone loss around implants supporting mandibular overdentures: a retrospective study.

    Science.gov (United States)

    Geckili, Onur; Mumcu, Emre; Bilhan, Hakan

    2012-05-01

    There remains controversy regarding the clinical reasons for late-implant bone loss, which is a critical factor in the long-term success of implant-supported overdentures. Assessment of the effect of such factors as attachment type, number of implants, gender, age, and maximum bite force (MBF) on marginal bone loss (MBL) around implants supporting mandibular overdentures. Sixty-two edentulous patients rehabilitated with two-, three-, or four-implant-supported mandibular overdentures at a university clinic between January 2006 and January 2007 and having a digital panoramic radiograph at the time of loading, were included in this study. All patients received digital panoramic radiographs, and MBL was measured by subtracting bone levels from the first radiograph. MBF was measured using a bite force transducer. The amount of bone loss 48 months after loading was found to be unrelated to gender, age, implant number, attachment type, and splinting (p = .741, p = .953, p = .640, p = .763, p = .370, respectively). A significant correlation was observed between the MBF and the MBL of distal implants on the right side (p implants on the left side (p = .011, 34.6%). MBL around implants supporting mandibular overdentures seems not to be affected by number of implants, attachment type, age, or gender; however, MBL is affected by MBF. © 2011 Wiley Periodicals, Inc.

  18. Lizard Bites

    Science.gov (United States)

    ... to the Professional version Home Injuries and Poisoning Bites and Stings Lizard Bites Medical Dictionary Also of Interest (Quiz) ... Version. DOCTORS: Click here for the Professional Version Bites and Stings Introduction to Bites and Stings Alligator, Crocodile, and ...

  19. Automatic HTS force measurement instrument

    Science.gov (United States)

    Sanders, S.T.; Niemann, R.C.

    1999-03-30

    A device is disclosed for measuring the levitation force of a high temperature superconductor sample with respect to a reference magnet includes a receptacle for holding several high temperature superconductor samples each cooled to superconducting temperature. A rotatable carousel successively locates a selected one of the high temperature superconductor samples in registry with the reference magnet. Mechanism varies the distance between one of the high temperature superconductor samples and the reference magnet, and a sensor measures levitation force of the sample as a function of the distance between the reference magnet and the sample. A method is also disclosed. 3 figs.

  20. Influence of Deformation and Stress between Bone and Implant from Various Bite Forces by Numerical Simulation Analysis

    Directory of Open Access Journals (Sweden)

    Hsin-Chung Cheng

    2017-01-01

    Full Text Available Endosseous oral implant is applied for orthodontic anchorage in subjects with multiple tooth agenesis. Its effectiveness under orthodontic loading has been demonstrated clinically and experimentally. This study investigates the deformation and stress on the bone and implant for different bite forces by three-dimensional (3D finite element (FE methods. A numerical simulation of deformation and stress distributions around implants was used to estimate the survival life for implants. The model was applied to determine the pattern and distribution of deformations and stresses within the endosseous implant and on supporting tissues when the endosseous implant is used for orthodontic anchorage. A threaded implant was placed in an edentulous segment of a human mandible with cortical and cancellous bone. Analytical results demonstrate that maximum stresses were always located around the implant neck in marginal bone. The results also reveal that the stress for oblique force has the maximum value followed by the horizontal force; the vertical force causes the stress to have the minimum value between implant and bone. Thus, this area should be preserved clinically to maintain the structure and function of a bone implant.

  1. Arthropod bites.

    Science.gov (United States)

    Juckett, Gregory

    2013-12-15

    The phylum Arthropoda includes arachnids and insects. Although their bites typically cause only local reactions, some species are venomous or transmit disease. The two medically important spiders in the United States are widow spiders (Latrodectus), the bite of which causes intense muscle spasms, and the brown recluse (Loxosceles), which may cause skin necrosis. Widow bites usually respond to narcotics, benzodiazepines, or, when necessary, antivenom. Most recluse bites resolve uneventfully without aggressive therapy and require only wound care and minor debridement. Tick bites can transmit diseases only after prolonged attachment to the host. Treatment of clothing with permethrin and proper tick removal greatly reduce the risk of infection. Ticks of medical importance in the United States include the black-legged tick, the Lone Star tick, and the American dog tick. The prophylactic use of a single dose of doxycycline for Lyme disease may be justified in high-risk areas of the country when an attached, engorged black-legged tick is removed. Bites from fleas, bedbugs, biting flies, and mosquitoes present as nonspecific pruritic pink papules, but the history and location of the bite can assist with diagnosis. Flea bites are usually on ankles, whereas mosquito bites are on exposed skin, and chigger bites tend to be along the sock and belt lines. Antihistamines are usually the only treatment required for insect bites; however, severe mosquito reactions (skeeter syndrome) may require prednisone. Applying insect repellent containing diethyltoluamide (DEET) 10% to 35% or picaridin 20% is the best method for preventing bites.

  2. Lizard Bites

    Science.gov (United States)

    ... Stings Alligator, Crocodile, and Iguana Bites Animal Bites Bee, Wasp, Hornet, and Ant ... in Arizona, Sonora, Mexico, and adjacent areas. The venom of these lizards is somewhat similar in content ...

  3. Direct measurements of intermolecular forces by chemical force microscopy

    Science.gov (United States)

    Vezenov, Dmitri Vitalievich

    1999-12-01

    Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the

  4. Measuring Forces between Oxide Surfaces Using the Atomic Force Microscope

    DEFF Research Database (Denmark)

    Pedersen, Henrik Guldberg; Høj, Jakob Weiland

    1996-01-01

    The interactions between colloidal particles play a major role in processing of ceramics, especially in casting processes. With the Atomic Force Microscope (AFM) it is possible to measure the inter-action force between a small oxide particle (a few micron) and a surface as function of surface...

  5. Axial force measurement for esophageal function testing

    DEFF Research Database (Denmark)

    Gravesen, Flemming Holbæk; Funch-Jensen, Peter; Gregersen, Hans

    2009-01-01

    force (force in radial direction) whereas the bolus moves along the length of esophagus in a distal direction. Force measurements in the longitudinal (axial) direction provide a more direct measure of esophageal transport function. The technique used to record axial force has developed from external...... documented using imaging modalities such as radiography and scintigraphy. This inconsistency using manometry has also been documented by axial force recordings. This underlines the lack of information when diagnostics are based on manometry alone. Increasing the volume of a bag mounted on a probe...

  6. Effect of Postnatal Myostatin Inhibition on Bite Mechanics in Mice.

    Directory of Open Access Journals (Sweden)

    Susan H Williams

    Full Text Available As a negative regulator of muscle size, myostatin (Mstn impacts the force-production capabilities of skeletal muscles. In the masticatory system, measures of temporalis-stimulated bite forces in constitutive myostatin KOs suggest an absolute, but not relative, increase in jaw-muscle force. Here, we assess the phenotypic and physiologic impact of postnatal myostatin inhibition on bite mechanics using an inducible conditional KO mouse in which myostatin is inhibited with doxycycline (DOX. Given the increased control over the timing of gene inactivation in this model, it may be more clinically-relevant for developing interventions for age-associated changes in the musculoskeletal system. DOX was administered for 12 weeks starting at age 4 months, during which time food intake was monitored. Sex, age and strain-matched controls were given the same food without DOX. Bite forces were recorded just prior to euthanasia after which muscle and skeletal data were collected. Food intake did not differ between control or DOX animals within each sex. DOX males were significantly larger and had significantly larger masseters than controls, but DOX and control females did not differ. Although there was a tendency towards higher absolute bite forces in DOX animals, this was not significant, and bite forces normalized to masseter mass did not differ. Mechanical advantage for incisor biting increased in the DOX group due to longer masseter moment arms, likely due to a more anteriorly-placed masseter insertion. Despite only a moderate increase in bite force in DOX males and none in DOX females, the increase in masseter mass in males indicates a potentially positive impact on jaw muscles. Our data suggest a sexual dimorphism in the role of mstn, and as such investigations into the sex-specific outcomes is warranted.

  7. Recombinant Salivary Proteins of Phlebotomus orientalis are Suitable Antigens to Measure Exposure of Domestic Animals to Sand Fly Bites.

    OpenAIRE

    Michal Sima; Blanka Ferencova; Alon Warburg; Iva Rohousova; Petr Volf

    2016-01-01

    Background Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs) using salivary gland homogenates (SGHs) as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replaceme...

  8. Sex-specific trade-offs and compensatory mechanisms: bite force and sprint speed pose conflicting demands on the design of geckos (Hemidactylus frenatus).

    Science.gov (United States)

    Cameron, S F; Wynn, M L; Wilson, R S

    2013-10-15

    One of the more intuitive viability costs that can result from the possession of exaggerated sexually selected traits is increased predation pressure as a result of reduced locomotor capacity. Despite mixed empirical support for such locomotor costs, recent studies suggest that such costs may be masked by compensatory traits that effectively offset any detrimental effects. In this study, we provide a comprehensive assessment of the locomotor costs associated with improved male-male competitive ability by simultaneously testing for locomotor trade-offs and potential compensatory mechanisms in territorial male and non-territorial female geckos. Fighting capacity and escape performance of male Asian house geckos (Hemidactylus frenatus) are likely to pose conflicting demands on the optimum phenotype for each task. Highly territorial and aggressive males may require greater investment in head size/strength but such an enhancement may affect overall escape performance. Among male geckos, we found that greater biting capacity because of larger head size was associated with reduced sprint performance; this trade-off was further exacerbated when sprinting on an incline. Females, however, showed no evidence of this trade-off on either flat or inclined surfaces. The sex specificity of this trade-off suggests that the sexes differ in their optimal strategies for dealing with the conflicting requirements of bite force and sprint speed. Unlike males, female H. frenatus had a positive association between hind-limb length and head size, suggesting that they have utilised a compensatory mechanism to alleviate the possible locomotor costs of larger head sizes. It appears that there is greater selection on traits that improve fighting ability (bite force) for males, but it is viability traits (sprint speed) that appear to be of greater importance for females. Our results emphasise that only by examining both functional trade-offs and potential compensatory mechanisms is it possible

  9. Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics

    OpenAIRE

    Bates, K. T.; Falkingham, P. L.

    2012-01-01

    Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex. Models predict that adult T. rex generated sustained bite forces of 35 000–57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling ...

  10. Animal Bites

    Science.gov (United States)

    Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their ... or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they ...

  11. The influence of gender and bruxism on the human maximum bite force Avaliação da influência do gênero e do bruxismo na força máxima de mordida

    Directory of Open Access Journals (Sweden)

    Patrícia dos Santos Calderon

    2006-12-01

    Full Text Available The objective of this research was to evaluate the influence of gender and bruxism on the maximum bite force. The concordance for the physical examination of bruxism between examiners was also evaluated. One hundred and eighteen individuals, from both genders, bruxists and non-bruxists, with an average age of 24 years, were selected for this purpose. For group establishment, every individual was submitted to a specific physical examination for bruxism (performed by three different examiners. Subjects were then divided into four groups according to gender and the presence of bruxism. The maximum bite force was measured using a gnathodynamometer at the first molar area, three times on each side, performed twice. The two measurements were made with a 10-day interval. The highest value was recorded. The mean maximum bite force was statistically higher for males (587.2 N when compared to females (424.9 N (p0.05. The concordance between examiners for physical examination of bruxism was considered optimal.O objetivo dessa pesquisa foi avaliar a influência do gênero e do bruxismo na força máxima de mordida. A concordância interexaminadores para o exame físico de bruxismo também foi avaliada. Cento e dezoito voluntários, com idade média de 24 anos, divididos por gênero e pela presença de bruxismo, foram selecionados. Para o estabelecimento da amostra todos os voluntários foram submetidos a um exame físico específico para bruxismo (realizado por três examinadores. Então, os voluntários foram divididos em quarto grupos de acordo com o gênero e a presença de bruxismo. A força máxima de mordida foi mensurada, com o auxílio de um gnatodinamômetro, na região de primeiro molar, três vezes de cada lado, em duas sessões distintas. As sessões foram separadas por um intervalo de 10 dias. O maior valor dentre os doze obtidos, foi utilizado como sendo a força máxima. A força máxima de mordida foi estatisticamente maior para o g

  12. Detecting chameleons through Casimir force measurements

    International Nuclear Information System (INIS)

    Brax, Philippe; Bruck, Carsten van de; Davis, Anne-Christine; Shaw, Douglas; Mota, David F.

    2007-01-01

    The best laboratory constraints on strongly coupled chameleon fields come not from tests of gravity per se but from precision measurements of the Casimir force. The chameleonic force between two nearby bodies is more akin to a Casimir-like force than a gravitational one: The chameleon force behaves as an inverse power of the distance of separation between the surfaces of two bodies, just as the Casimir force does. Additionally, experimental tests of gravity often employ a thin metallic sheet to shield electrostatic forces; however, this sheet masks any detectable signal due to the presence of a strongly coupled chameleon field. As a result of this shielding, experiments that are designed to specifically test the behavior of gravity are often unable to place any constraint on chameleon fields with a strong coupling to matter. Casimir force measurements do not employ a physical electrostatic shield and as such are able to put tighter constraints on the properties of chameleons fields with a strong matter coupling than tests of gravity. Motivated by this, we perform a full investigation on the possibility of testing chameleon models with both present and future Casimir experiments. We find that present-day measurements are not able to detect the chameleon. However, future experiments have a strong possibility of detecting or rule out a whole class of chameleon models

  13. Measurement of tool forces in diamond turning

    Energy Technology Data Exchange (ETDEWEB)

    Drescher, J.; Dow, T.A.

    1988-12-01

    A dynamometer has been designed and built to measure forces in diamond turning. The design includes a 3-component, piezoelectric transducer. Initial experiments with this dynamometer system included verification of its predicted dynamic characteristics as well as a detailed study of cutting parameters. Many cutting experiments have been conducted on OFHC Copper and 6061-T6 Aluminum. Tests have involved investigation of velocity effects, and the effects of depth and feedrate on tool forces. Velocity has been determined to have negligible effects between 4 and 21 m/s. Forces generally increase with increasing depth of cut. Increasing feedrate does not necessarily lead to higher forces. Results suggest that a simple model may not be sufficient to describe the forces produced in the diamond turning process.

  14. Knitting Force Measurement on Flat Knitting Machines

    Directory of Open Access Journals (Sweden)

    A. Fouda

    2014-01-01

    Full Text Available Knittability can be defined as the ability of yarns to run on knitting machines without problems. Knittability can be achieved when less stress is applied on the knitting machine parts by the knitting yarns. This paper presents a novel measuring system for the knitting force needed to perform knitting yarns on flat knitting machine based on data acquisition system (DAS. The proposed system is used to measure the knitting force at different machine settings and different properties of the knitting yarns to determine the optimal production conditions. For this reason, three types of knitted fabric structures (single jersey, Rib 1 × 1, and full cardigan with three different loop lengths and five different twists of ply yarn were produced. The obtained results showed the optimal yarn ply twist factor (αe which gave minimum knitting force (less stress on needles or knitting yarns at different loop lengths for each structure.

  15. Unsteady Aerodynamic Force Sensing from Measured Strain

    Science.gov (United States)

    Pak, Chan-Gi

    2016-01-01

    A simple approach for computing unsteady aerodynamic forces from simulated measured strain data is proposed in this study. First, the deflection and slope of the structure are computed from the unsteady strain using the two-step approach. Velocities and accelerations of the structure are computed using the autoregressive moving average model, on-line parameter estimator, low-pass filter, and a least-squares curve fitting method together with analytical derivatives with respect to time. Finally, aerodynamic forces over the wing are computed using modal aerodynamic influence coefficient matrices, a rational function approximation, and a time-marching algorithm. A cantilevered rectangular wing built and tested at the NASA Langley Research Center (Hampton, Virginia, USA) in 1959 is used to validate the simple approach. Unsteady aerodynamic forces as well as wing deflections, velocities, accelerations, and strains are computed using the CFL3D computational fluid dynamics (CFD) code and an MSC/NASTRAN code (MSC Software Corporation, Newport Beach, California, USA), and these CFL3D-based results are assumed as measured quantities. Based on the measured strains, wing deflections, velocities, accelerations, and aerodynamic forces are computed using the proposed approach. These computed deflections, velocities, accelerations, and unsteady aerodynamic forces are compared with the CFL3D/NASTRAN-based results. In general, computed aerodynamic forces based on the lifting surface theory in subsonic speeds are in good agreement with the target aerodynamic forces generated using CFL3D code with the Euler equation. Excellent aeroelastic responses are obtained even with unsteady strain data under the signal to noise ratio of -9.8dB. The deflections, velocities, and accelerations at each sensor location are independent of structural and aerodynamic models. Therefore, the distributed strain data together with the current proposed approaches can be used as distributed deflection

  16. Human bites - self-care

    Science.gov (United States)

    Bites - human - self-care ... Human bites can occur in 2 ways: If someone bites you If your hand comes into contact ... bite to express anger or other negative feelings. Human bites may be more dangerous than animal bites. ...

  17. Nanoindentation and atomic force microscopy measurements on ...

    Indian Academy of Sciences (India)

    Unknown

    substrate temperature to ~ 130°C during the deposition. The growth rate for TiN coatings was ~ 0⋅82 µm/h. The nanoindentation measurements were performed with an instrument consisting of a nanohardness tester. (CSEM Instruments) and an integrated optical (Nikon)/ atomic force microscope (surface imaging systems).

  18. Memory effect o force measurements at nanoscales

    International Nuclear Information System (INIS)

    Lisy, V.; Tothova, J.

    2011-01-01

    we have obtained an exact solution for the drift velocity of a Brownian particle in an incompressible fluid under the action of a constant force, taking into account the hydrodynamic memory in the particle motion. This velocity is proportional to the applied force but depends in a complicated manner on the time of observation t. At short times it is proportional to t and at long times it contains algebraic tails, the longest-lived of which being ∼ t -1/ 2. Due to this the velocity very slowly approaches the limiting value F/γ. As a consequence, the force F can significantly differ from the value that would be extracted from the drift measurements neglecting the inertial effects, which is a standard assumption in the interpretation of such experiments. The presented method can be equally applicable in the case of force linearly depending on the particle position. For nonlinear forces, first the open question about the choice of convention to be used in stochastic calculus should be resolved. (authors)

  19. Bite marks.

    Science.gov (United States)

    Fischman, Stuart L

    2002-12-01

    A simple and practical method for the evaluation of bite mark evidence has been described. There are many other methods, some quite complicated, using overlays, computer analysis and mathematical formulae. This author prefers to adhere to the "KISS principle: "Keep It Simple, Stupid." A jury is generally more willing to accept the positioning of a study model on a one-to-one life-size photograph rather than be led through a complicated analytical procedure. If the juror can hold the model and photograph in his/her hand and see that the teeth and bite mark match (or do not match), data summation can be much more direct. Numerous publications describe more complex matching procedures should circumstances warrant.

  20. Snake bite.

    Science.gov (United States)

    Warrell, David A

    2010-01-02

    Snake bite is a common and frequently devastating environmental and occupational disease, especially in rural areas of tropical developing countries. Its public health importance has been largely ignored by medical science. Snake venoms are rich in protein and peptide toxins that have specificity for a wide range of tissue receptors, making them clinically challenging and scientifically fascinating, especially for drug design. Although the full burden of human suffering attributable to snake bite remains obscure, hundreds of thousands of people are known to be envenomed and tens of thousands are killed or maimed by snakes every year. Preventive efforts should be aimed towards education of affected communities to use proper footwear and to reduce the risk of contact with snakes to a minimum through understanding of snakes' behaviour. To treat envenoming, the production and clinical use of antivenom must be improved. Increased collaboration between clinicians, epidemiologists, and laboratory toxinologists should enhance the understanding and treatment of envenoming. Copyright 2010 Elsevier Ltd. All rights reserved.

  1. Cat and Dog Bites

    Science.gov (United States)

    ... Wellness Staying Healthy Pets and Animals Cat and Dog Bites Cat and Dog Bites Share Print Cat and dog bites are common injuries. A family pet or ... bites. Path to safety If a cat or dog bites you, you should: Wash the wound gently ...

  2. Insect Bites and Stings

    Science.gov (United States)

    Most insect bites are harmless, though they sometimes cause discomfort. Bee, wasp, and hornet stings and fire ant bites usually hurt. Mosquito and flea bites usually itch. Insects can also spread diseases. In the United States, ...

  3. Dog Bite Emergencies

    Science.gov (United States)

    ... Emergency Care Animal Welfare Veterinary Careers Public Health Dog Bite Emergencies What do I do if I’ ... vaccination records. What do I do if my dog bites someone? Dog bites are scary for everyone ...

  4. Squeezed noise in precision force measurements

    International Nuclear Information System (INIS)

    Bocko, M.F.; Bordoni, F.; Fuligni, F.; Johnson, W.W.

    1986-01-01

    The effort to build gravitational radiation antennae with sensitivity sufficient to detect bursts of radiation from supernovae in the Virgo cluster of galaxies has caused a consideration of the fundamental limits for the detection of weak forces. The existing Weber bar detectors will be eventually limited, by the phase insensitive transducers now used, to noise temperatures no better than that of the first amplifier which follows the transducer. Even for a quantum limited amplifier this may not give the sensitivity required to definitively detect gravitational radiation. In a 'back action evasion' measurement a specific phase sensitive transducer would be used. It is believed that by the technique of measuring one of the two antenna phases it is possible to reach an effective noise temperature for the measured phase which is far below the amplifier noise temperature. This is at the expense of an infinite noise temperature in the unmeasured antenna phase and is thus described as squeezing the noise. The authors outline the theoretical model for the behavior of such systems and present data from several experiments which demonstrate the main features of a back action evasion measurement. (Auth.)

  5. Animal Bites: First Aid

    Science.gov (United States)

    First aid Animal bites: First aid Animal bites: First aid By Mayo Clinic Staff These guidelines can help you care for a minor animal bite, such ... 26, 2017 Original article: http://www.mayoclinic.org/first-aid/first-aid-animal-bites/basics/ART-20056591 . Mayo ...

  6. Which dogs bite?

    OpenAIRE

    Jarrett, P

    1991-01-01

    Young children (less than 11 years old) are a particular risk group for dog bites. Dog bites commonly occur from the family pet. Alsatian or alsatian mixes are the biggest group in the study causing dog bites. Alsations are a popular breed. By comparison Retrievers (Labrador and Golden), also a popular breed, caused few bites.

  7. Mathematical model of the human jaw system simulating static biting and movements after unloading

    NARCIS (Netherlands)

    Slager, GEC; Otten, E; van Eijden, TMGJ; van Willigen, JD

    1997-01-01

    When the resistance to a forceful isometric bite is suddenly removed in unloading experiments, the bite force drops to zero and the mandible reaches a constant velocity. This occurs at an initial bite force of 100 N after similar to 12 ms when the incisors have moved 4.5 mm. Reflex activity is far

  8. Morphology, ornaments and performance in two chameleon ecomorphs: is the casque bigger than the bite?

    Science.gov (United States)

    Measey, G John; Hopkins, Kevin; Tolley, Krystal A

    2009-01-01

    The evolution of ecomorphs within a species may represent either unique evolutionary events or multiple convergent events in similar environments. Functional studies of differing morphological traits of ecomorphs have been important to elucidate their role in adaptive radiations. The Cape dwarf chameleon, Bradypodion pumilum, has two ecomorphs: a large, brightly colored, ornate form found in closed habitats, and a small, dull form with reduced ornamentation found in open vegetation. The typical form is known to use casque size to communicate fighting ability, but it is unknown whether this is an honest signal and whether casque size is related to bite force. We show through a population genetic analysis that these ecomorphs are not separate genetic lineages but the result of multiple transitions between closed and open habitats. From measurements of ornamental and non-ornamental morphological characters and bite force in 105 chameleons, we find that bite force is significantly related to head size and is best predicted by head width. Bite force was reasonably predicted by casque height in ecomorphs from closed habitats, but not in those from open habitats. For size-adjusted data, open habitat males had wider heads, biting harder than closed habitat males. Our data suggest honesty in signaling for closed habitat ecomorphs, but for open habitat ecomorphs communication is different, a finding commensurate with the common framework for species radiations.

  9. Nanoindentation and atomic force microscopy measurements on ...

    Indian Academy of Sciences (India)

    Unknown

    CSEM Instruments) and an integrated optical (Nikon)/ atomic force microscope ... The results reported herein represent averages of the group. For each loading/ unloading cycle, the load was plotted against the dis- placement of the indenter.

  10. Tail-biting: a new perspective.

    Science.gov (United States)

    Taylor, Nina R; Main, David C J; Mendl, Mike; Edwards, Sandra A

    2010-11-01

    Tail-biting data from different studies are difficult to compare because a range of definitions of tail-biting behaviour and tail-biting lesions are used. Although records from abattoirs provide a large database, their usefulness is restricted as tail-biting is under-recorded and environmental and husbandry factors associated with the behaviour are unlikely to be known. Both farm and abattoir data provide no information on the number of pigs biting, only those bitten. Studying individual animals that tail-bite should give a better understanding of the pig's motivation to tail-bite and which of the components of its environment should be adjusted to improve welfare. This review examines the existing literature on tail-biting in pigs but considered from a new perspective using three different descriptive behavioural types, namely, 'two-stage', 'sudden-forceful' and 'obsessive', each of which may have different motivational bases. The article also considers the different environmental and husbandry factors which may affect each type of behaviour and discusses why this is such a complicated field and why it is often difficult to draw conclusions from available research. Copyright © 2009 Elsevier Ltd. All rights reserved.

  11. Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics.

    Science.gov (United States)

    Bates, K T; Falkingham, P L

    2012-08-23

    Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex. Models predict that adult T. rex generated sustained bite forces of 35 000-57 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex, associated with an expansion of prey range in adults to include the largest contemporaneous animals.

  12. Sound Bites that Bite Back

    DEFF Research Database (Denmark)

    Villadsen, Lisa Storm

    2017-01-01

    In 2012 the Danish Minister for Economic Affairs and the Interior, Margrethe Vestager, spoke four words that would haunt her for weeks and months to come. At a press conference she concluded an answer to a touchy political question with the words: ‘That’s the way it is’ [Sådan er det jo]. This la......In 2012 the Danish Minister for Economic Affairs and the Interior, Margrethe Vestager, spoke four words that would haunt her for weeks and months to come. At a press conference she concluded an answer to a touchy political question with the words: ‘That’s the way it is’ [Sådan er det jo...... such massive rhetorical fallout, and I consider Vestager’s attempt at re-appropriating the sound bite as I engage ancient and contemporary rhetorical theory. In a time where a main concern is with the seeming triumph of emotion over reason in political debate, this case illustrates the dangers of over......-relying on reason alone in politics and speaks to the protean nature of rhetorical agency in the age of social media....

  13. Theoretical Models for Surface Forces and Adhesion and Their Measurement Using Atomic Force Microscopy

    Science.gov (United States)

    Leite, Fabio L.; Bueno, Carolina C.; Da Róz, Alessandra L.; Ziemath, Ervino C.; Oliveira, Osvaldo N.

    2012-01-01

    The increasing importance of studies on soft matter and their impact on new technologies, including those associated with nanotechnology, has brought intermolecular and surface forces to the forefront of physics and materials science, for these are the prevailing forces in micro and nanosystems. With experimental methods such as the atomic force spectroscopy (AFS), it is now possible to measure these forces accurately, in addition to providing information on local material properties such as elasticity, hardness and adhesion. This review provides the theoretical and experimental background of AFS, adhesion forces, intermolecular interactions and surface forces in air, vacuum and in solution. PMID:23202925

  14. Theoretical models for surface forces and adhesion and their measurement using atomic force microscopy.

    Science.gov (United States)

    Leite, Fabio L; Bueno, Carolina C; Da Róz, Alessandra L; Ziemath, Ervino C; Oliveira, Osvaldo N

    2012-10-08

    The increasing importance of studies on soft matter and their impact on new technologies, including those associated with nanotechnology, has brought intermolecular and surface forces to the forefront of physics and materials science, for these are the prevailing forces in micro and nanosystems. With experimental methods such as the atomic force spectroscopy (AFS), it is now possible to measure these forces accurately, in addition to providing information on local material properties such as elasticity, hardness and adhesion. This review provides the theoretical and experimental background of afs, adhesion forces, intermolecular interactions and surface forces in air, vacuum and in solution.

  15. The effect of patch potentials in Casimir force measurements determined by heterodyne Kelvin probe force microscopy.

    Science.gov (United States)

    Garrett, Joseph L; Somers, David; Munday, Jeremy N

    2015-06-03

    Measurements of the Casimir force require the elimination of the electrostatic force between the surfaces. However, due to electrostatic patch potentials, the voltage required to minimize the total force may not be sufficient to completely nullify the electrostatic interaction. Thus, these surface potential variations cause an additional force, which can obscure the Casimir force signal. In this paper, we inspect the spatially varying surface potential of e-beamed, sputtered, sputtered and annealed, and template stripped gold surfaces with Heterodyne amplitude modulated Kelvin probe force microscopy (HAM-KPFM). It is demonstrated that HAM-KPFM improves the spatial resolution of surface potential measurements compared to amplitude modulated Kelvin probe force microscopy. We find that patch potentials vary depending on sample preparation, and that the calculated pressure can be similar to the pressure difference between Casimir force calculations employing the plasma and Drude models.

  16. Human bites (image)

    Science.gov (United States)

    Human bites present a high risk of infection. Besides the bacteria which can cause infection, there is ... the wound extends below the skin. Anytime a human bite has broken the skin, seek medical attention.

  17. Insect bites and stings

    Science.gov (United States)

    ... Insect and spider bites cause more deaths from venom reactions than bites from snakes. ... Some people have severe, life-threatening reactions to bee stings ... or lightheadedness Abdominal pain or vomiting Rash or flushing

  18. Bug Bites and Stings

    Science.gov (United States)

    ... can carry other diseases, such as malaria and dengue fever. Spider Bites Most spider bites are minor, ... Clean the area with soap and water, and treat with an antiseptic or antibiotic cream to avoid ...

  19. Roughness in Surface Force Measurements: Extension of DLVO Theory To Describe the Forces between Hafnia Surfaces.

    Science.gov (United States)

    Eom, Namsoon; Parsons, Drew F; Craig, Vincent S J

    2017-07-06

    The interaction between colloidal particles is commonly viewed through the lens of DLVO theory, whereby the interaction is described as the sum of the electrostatic and dispersion forces. For similar materials acting across a medium at pH values remote from the isoelectric point the theory typically involves an electrostatic repulsion that is overcome by dispersion forces at very small separations. However, the dominance of the dispersion forces at short separations is generally not seen in force measurements, with the exception of the interaction between mica surfaces. The discrepancy for silica surfaces has been attributed to hydration forces, but this does not explain the situation for titania surfaces where the dispersion forces are very much larger. Here, the interaction forces between very smooth hafnia surfaces have been measured using the colloid probe technique and the forces evaluated within the DLVO framework, including both hydration forces and the influence of roughness. The measured forces across a wide range of pH at different salt concentrations are well described with a single parameter for the surface roughness. These findings show that even small degrees of surface roughness significantly alter the form of the interaction force and therefore indicate that surface roughness needs to be included in the evaluation of surface forces between all surfaces that are not ideally smooth.

  20. Recombinant Salivary Proteins of Phlebotomus orientalis are Suitable Antigens to Measure Exposure of Domestic Animals to Sand Fly Bites.

    Directory of Open Access Journals (Sweden)

    Michal Sima

    2016-03-01

    Full Text Available Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs using salivary gland homogenates (SGHs as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replacement of SGH with recombinant salivary proteins. In East Africa, Phlebotomus orientalis is the main vector of Leishmania donovani, a trypanosomatid parasite causing visceral leishmaniasis. We tested recombinant salivary proteins derived from Ph. orientalis saliva to study exposure of domestic animals to this sand fly species.Antigenic salivary proteins from Ph. orientalis were identified by immunoblot and mass spectrometry. Recombinant apyrase rPorSP15, yellow-related protein rPorSP24, ParSP25-like protein rPorSP65, D7-related protein rPorSP67, and antigen 5-related protein rPorSP76 were tested using ELISA with sera of domestic animals from L. donovani foci in Ethiopia where Ph. orientalis is present. Our results highlighted recombinant yellow-related protein rPorSP24 as the most promising antigen, displaying a high positive correlation coefficient as well as good sensitivity and specificity when compared to SGH. This recombinant protein was the most suitable one for testing sera of dogs, sheep, and goats. In addition, a different antigen, rPorSP65 was found efficacious for testing canine sera.Recombinant salivary proteins of Ph. orientalis, specifically rPorSP24, were shown to successfully substitute SGH in serological experiments to measure exposure of domestic animals to Ph. orientalis, the vector of L. donovani. The results suggest that rPorSP24 might be a suitable antigen for detecting anti-Ph. orientalis antibody-mediated reactions also in other host species.

  1. Recombinant Salivary Proteins of Phlebotomus orientalis are Suitable Antigens to Measure Exposure of Domestic Animals to Sand Fly Bites.

    Science.gov (United States)

    Sima, Michal; Ferencova, Blanka; Warburg, Alon; Rohousova, Iva; Volf, Petr

    2016-03-01

    Certain salivary proteins of phlebotomine sand flies injected into the host skin during blood-feeding are highly antigenic and elicit strong antibody-mediated immune responses in repeatedly-exposed hosts. These antibodies can be measured by enzyme-linked immuno sorbent assays (ELISAs) using salivary gland homogenates (SGHs) as the source of antigens and serve as a markers for exposure to biting sand flies. Large-scale screening for anti-sand fly saliva antibodies requires replacement of SGH with recombinant salivary proteins. In East Africa, Phlebotomus orientalis is the main vector of Leishmania donovani, a trypanosomatid parasite causing visceral leishmaniasis. We tested recombinant salivary proteins derived from Ph. orientalis saliva to study exposure of domestic animals to this sand fly species. Antigenic salivary proteins from Ph. orientalis were identified by immunoblot and mass spectrometry. Recombinant apyrase rPorSP15, yellow-related protein rPorSP24, ParSP25-like protein rPorSP65, D7-related protein rPorSP67, and antigen 5-related protein rPorSP76 were tested using ELISA with sera of domestic animals from L. donovani foci in Ethiopia where Ph. orientalis is present. Our results highlighted recombinant yellow-related protein rPorSP24 as the most promising antigen, displaying a high positive correlation coefficient as well as good sensitivity and specificity when compared to SGH. This recombinant protein was the most suitable one for testing sera of dogs, sheep, and goats. In addition, a different antigen, rPorSP65 was found efficacious for testing canine sera. Recombinant salivary proteins of Ph. orientalis, specifically rPorSP24, were shown to successfully substitute SGH in serological experiments to measure exposure of domestic animals to Ph. orientalis, the vector of L. donovani. The results suggest that rPorSP24 might be a suitable antigen for detecting anti-Ph. orientalis antibody-mediated reactions also in other host species.

  2. Measuring Agglomeration Forces in a Financial Center

    OpenAIRE

    Bourgain, Arnaud; Pieretti, Patrice

    2006-01-01

    Basing on Scitovsky's (1954) definition of external economies and applying the method of Caballero and Lyons (1990) to macro data of Luxembourg services industry, we find significant agglomeration forces between financial intermediaries (downstream industry) on the one hand and business services and computer industry (upstream industries) on the other.

  3. Nanoindentation and atomic force microscopy measurements on ...

    Indian Academy of Sciences (India)

    The films were deposited on silicon (111) substrates at various process conditions, e.g. substrate bias voltage (B) and nitrogen partial pressure. Mechanical properties of the coatings were investigated by a nanoindentation technique. Force vs displacement curves generated during loading and unloading of a Berkovich ...

  4. Bites and stings.

    Science.gov (United States)

    Charles, Janice; Fahridin, Salma; Britt, Helena

    2009-11-01

    Of the 426 bite or sting problems managed, 312 (73%) were caused by insects. There were 114 other types of bites recorded, the most common being dog and spider bites. There were five cases of toxicity from aquatic animal stings or adverse reactions to bee stings (Table 1).

  5. The Stages of Biting.

    Science.gov (United States)

    Marlowe, Dana

    1999-01-01

    Describes infant and toddler biting behavior as related to developmental differences in exploring the environment, learning cause-effect relationships, and using power to elicit a response. Discusses ways to deal with biting at each level, how to support parents dealing with the behavior at home, and the importance of taking biting related to…

  6. Exotic reptile bites.

    Science.gov (United States)

    Kelsey, J; Ehrlich, M; Henderson, S O

    1997-09-01

    Reptiles are a growing part of the exotic pet trade, and reptile bites have been considered innocuous in the emergency medicine literature. Two cases are reported of reptile bites, one from a green iguana and the other from a reticulated python. The treatment concerns associated with reptile bites are discussed.

  7. A Novel Device for Measuring Forces in Endoluminal Procedures

    Directory of Open Access Journals (Sweden)

    Tommaso Ranzani

    2015-08-01

    Full Text Available In this paper a simple but effective measuring system for endoluminal procedures is presented. The device allows measuring forces during the endoluminal manipulation of tissues with a standard surgical instrument for laparoscopic procedures. The force measurement is performed by recording both the forces applied directly by the surgeon at the instrument handle and the reaction forces on the access port. The measuring system was used to measure the forces necessary for appropriate surgical manipulation of tissues during transanal endoscopic microsurgery (TEM. Ex-vivo and in-vivo measurements were performed, reported and discussed. The obtained data can be used for developing and appropriately dimensioning novel dedicated instrumentation for TEM procedures.

  8. Incidence of dog bites in Milwaukee, wis.

    Science.gov (United States)

    Ndon, J A; Jach, G J; Wehrenberg, W B

    1996-04-01

    Dogs are everywhere. The incidence of and injuries caused by dog bites have grown to such epidemic proportions in certain parts of the United States that they are now considered a major public health concern. Playful Rover is no longer a harmless pet. Uncontrolled, he now can be considered a public nuisance. In this study, we evaluated the epidemiology of dog bites recorded in Milwaukee, for calendar years 1989-1991. This assessment included anatomical location of bites, victims' ages, behavioral antecedents, leading up to the bite incidents, season of the year, and animal ownership. The evaluation also measured the correlation coefficient between the frequency of dog bite incidents and median household income distribution within the city. During the 3-year period, a total of 3,926 animal bites, including 3,244 (83%) dog bites, were reported to the City of Milwaukee Department of Health. Of all the dog bites reported, 60% were on the upper extremities. Children less than 15 years old sustained 44% of the injuries, mostly to the head and face. Provocation by the victim accounted for 19% of the cases. The majority of the incidents (67%) occurred during the spring and summer months. In 49% of all cases, the victims families or neighbors owned the animals involved in the biting. Researchers also observed a significant negative correlation between bites and median household income distribution. Study results suggest a need to educate the public about the magnitude of dog-bite problems, enforce leash laws and impound stray dogs as an integral part of prevention programs.

  9. Measurement of dynamic and static radiation force on a sphere.

    Science.gov (United States)

    Chen, Shigao; Silva, Glauber T; Kinnick, Randall R; Greenleaf, James F; Fatemi, Mostafa

    2005-05-01

    Dynamic radiation force from ultrasound has found increasing applications in elasticity imaging methods such as vibro-acoustography. Radiation force that has both static and dynamic components can be produced by interfering two ultrasound beams of slightly different frequencies. This paper presents a method to measure both static and dynamic components of the radiation force on a sphere suspended by thin threads in water. Due to ultrasound radiation force, the sphere deflects to an equilibrant position and vibrates around it. The static radiation force is estimated from the deflection of the sphere. The dynamic radiation force is estimated from the calculated radiation impedance of the sphere and its vibration speed measured by a laser vibrometer. Experimental results on spheres of different size, vibrated at various frequencies, confirm the theoretical prediction that the dynamic and static radiation force on a sphere have approximately equal magnitudes [G. T. Silva, Phys. Rev. E 71, 056617 (2005)].

  10. an extended octagonal ring dynamometer for measurement of forces

    African Journals Online (AJOL)

    NIJOTECH

    ABSTRACT. The analysis, design, construction, evaluation and use of an extended octagonal ring dynamometer for measurement of draught, vertical force and moment on a simple tillage tool are presented. The dynamometer was used to measure tool forces as functions of depth, rake angle and speed, for a wide plane ...

  11. An ABS control logic based on wheel force measurement

    Science.gov (United States)

    Capra, D.; Galvagno, E.; Ondrak, V.; van Leeuwen, B.; Vigliani, A.

    2012-12-01

    The paper presents an anti-lock braking system (ABS) control logic based on the measurement of the longitudinal forces at the hub bearings. The availability of force information allows to design a logic that does not rely on the estimation of the tyre-road friction coefficient, since it continuously tries to exploit the maximum longitudinal tyre force. The logic is designed by means of computer simulation and then tested on a specific hardware in the loop test bench: the experimental results confirm that measured wheel force can lead to a significant improvement of the ABS performances in terms of stopping distance also in the presence of road with variable friction coefficient.

  12. Estimation of Dog-Bite Risk and Related Morbidity Among Personnel Working With Military Dogs.

    Science.gov (United States)

    Schermann, H; Eiges, N; Sabag, A; Kazum, E; Albagli, A; Salai, M; Shlaifer, A

    Soldiers serving in the Israel Defense Force Military Working Dogs (MWD) Unit spend many hours taming dogs' special skills, taking them on combat missions, and performing various dogkeeping activities. During this intensive work with the aggressive military dogs, bites are common, and some of them result in permanent disability. However, this phenomenon has not been quantified or reported as an occupational hazard. This was a retrospective cohort study based on self-administered questionnaires. Information was collected about soldiers' baseline demographics, duration of the experience of working with dogs, total number of bites they had, circumstances of bite events, and complications and medical treatment of each bite. Bite risk was quantified by incidence, mean time to first bite, and a Cox proportional hazards model. Rates of complications and the medical burden of bites were compared between combat soldiers and noncombat dogkeepers. Bite locations were presented graphically. Seventy-eight soldiers participated and reported on 139 bites. Mean time of working with dogs was 16 months (standard deviation, ±9.4 months). Overall bite incidence was 11 bites per 100 person-months; the mean time to first bite event was 6.3 months. The Cox proportional hazards model showed that none of baseline characteristics significantly increased bite hazard. About 90% of bites occurred during routine activities, and 3.3% occurred on combat missions. Only in 9% of bite events did soldiers observed the safety precautions code. Bite complications included fractures, need for intravenous antibiotic treatment and surgical repair, prominent scarring, diminished sensation, and stiffness of proximal joints. Bite complications were similar between combat soldiers and dogkeepers. Most bites (57%) were located on hands and arms. MWD bites are an occupational hazard resulting in significant medical burden. Hands and arms were most common bite locations. Observance of safety precautions may be

  13. In Vivo Measurement of Mesokinesis in Gekko gecko: The Role of Cranial Kinesis during Gape Display, Feeding and Biting.

    Directory of Open Access Journals (Sweden)

    Stéphane J Montuelle

    Full Text Available Cranial kinesis refers to movements of skeletal sub-units relative to one another at mobile sutures within the skull. The presence and functional significance of cranial kinesis has been investigated in various vertebrates, with much of our understanding coming from comparative studies and manipulation of ligamentous specimens. Drawing on these studies, cranial kinesis in lizards has been modeled as a four-bar linkage system involving streptostyly (rotation of the quadrate, hypokinesis (dorsoventral flexion and extension of the palato-maxillary sub-unit, mesokinesis (dorsoventral flexion and extension of the snout at the fronto-parietal suture and metakinesis (sliding movements between parietal and supraocciptal bones. In vivo studies, although limited, suggest that cranial kinesis serves an important role during routine behaviors such as feeding. Here, we use X-ray Reconstruction Of Moving Morphology to further quantify mesokinesis in vivo in Gekko gecko during three routine behaviors: gape display, biting and post-ingestion feeding. During gape display, the snout rotates dorsally above rest position, with mesokinesis accounting for a 10% increase in maximum gape over that achieved solely by the depression of the lower jaw. During defensive biting, the snout rotates ventrally below rest position to participate in gape closure. Finally, ventroflexion of the snout also occurs during post-ingestion feeding, accounting for 42% of gape closure during intra-oral transport, 86% during puncture-crushing, and 61% during pharyngeal packing. Mesokinesis thus appears to facilitate prey puncturing by allowing the snout to rotate ventrally so that the upper teeth pierce the prey item, thus limiting the need for large movements of the lower jaw. This is suggested to maintain a firm grip on the prey and reduce the possibility of prey escape. More generally, this study demonstrates that mesokinesis is a key component of defensive biting and gape display

  14. Micromechanical cohesion force measurements to determine cyclopentane hydrate interfacial properties.

    Science.gov (United States)

    Aman, Zachary M; Joshi, Sanjeev E; Sloan, E Dendy; Sum, Amadeu K; Koh, Carolyn A

    2012-06-15

    Hydrate aggregation and deposition are critical factors in determining where and when hydrates may plug a deepwater flowline. We present the first direct measurement of structure II (cyclopentane) hydrate cohesive forces in the water, liquid hydrocarbon and gas bulk phases. For fully annealed hydrate particles, gas phase cohesive forces were approximately twice that obtained in a liquid hydrocarbon phase, and approximately six times that obtained in the water phase. Direct measurements show that hydrate cohesion force in a water-continuous bulk may be only the product of solid-solid cohesion. When excess water was present on the hydrate surface, gas phase cohesive forces increased by a factor of three, suggesting the importance of the liquid or quasi-liquid layer (QLL) in determining cohesive force. Hydrate-steel adhesion force measurements show that, when the steel surface is coated with hydrophobic wax, forces decrease up to 96%. As the micromechanical force technique is uniquely capable of measuring hydrate-surface forces with variable contact time, the present work contains significant implications for hydrate applications in flow assurance. Copyright © 2012 Elsevier Inc. All rights reserved.

  15. Direct measurements of the frequency-dependent dielectrophoresis force.

    Science.gov (United States)

    Wei, Ming-Tzo; Junio, Joseph; Ou-Yang, H Daniel

    2009-01-02

    Dielectrophoresis (DEP), the phenomenon of directed motion of electrically polarizable particles in a nonuniform electric field, is promising for applications in biochemical separation and filtration. For colloidal particles in suspension, the relaxation of the ionic species in the shear layer gives rise to a frequency-dependent, bidirectional DEP force in the radio frequency range. However, quantification methods of the DEP force on individual particles with the pico-Newton resolution required for the development of theories and design of device applications are lacking. We report the use of optical tweezers as a force sensor and a lock-in phase-sensitive technique for analysis of the particle motion in an amplitude modulated DEP force. The coherent detection and sensing scheme yielded not only unprecedented sensitivity for DEP force measurements, but also provided a selectivity that clearly distinguishes the pure DEP force from all the other forces in the system, including electrophoresis, electro-osmosis, heat-induced convection, and Brownian forces, all of which can hamper accurate measurements through other existing methods. Using optical tweezers-based force transducers already developed in our laboratory, we have results that quantify the frequency-dependent DEP force and the crossover frequency of individual particles with this new experimental method.

  16. Molecular force sensors to measure stress in cells

    International Nuclear Information System (INIS)

    Prabhune, Meenakshi; Rehfeldt, Florian; Schmidt, Christoph F

    2017-01-01

    Molecularly generated forces are essential for most activities of biological cells, but also for the maintenance of steady state or homeostasis. To quantitatively understand cellular dynamics in migration, division, or mechanically guided differentiation, it will be important to exactly measure stress fields within the cell and the extracellular matrix. Traction force microscopy and related techniques have been established to determine the stress transmitted from adherent cells to their substrates. However, different approaches are needed to directly assess the stress generated inside the cell. This has recently led to the development of novel molecular force sensors. In this topical review, we briefly mention methods used to measure cell-external forces, and then summarize and explain different designs for the measurement of cell-internal forces with their respective advantages and disadvantages. (topical review)

  17. Molecular force sensors to measure stress in cells

    Science.gov (United States)

    Prabhune, Meenakshi; Rehfeldt, Florian; Schmidt, Christoph F.

    2017-06-01

    Molecularly generated forces are essential for most activities of biological cells, but also for the maintenance of steady state or homeostasis. To quantitatively understand cellular dynamics in migration, division, or mechanically guided differentiation, it will be important to exactly measure stress fields within the cell and the extracellular matrix. Traction force microscopy and related techniques have been established to determine the stress transmitted from adherent cells to their substrates. However, different approaches are needed to directly assess the stress generated inside the cell. This has recently led to the development of novel molecular force sensors. In this topical review, we briefly mention methods used to measure cell-external forces, and then summarize and explain different designs for the measurement of cell-internal forces with their respective advantages and disadvantages.

  18. Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

    Directory of Open Access Journals (Sweden)

    Adam Sweetman

    2014-04-01

    Full Text Available In principle, non-contact atomic force microscopy (NC-AFM now readily allows for the measurement of forces with sub-nanonewton precision on the atomic scale. In practice, however, the extraction of the often desired ‘short-range’ force from the experimental observable (frequency shift is often far from trivial. In most cases there is a significant contribution to the total tip–sample force due to non-site-specific van der Waals and electrostatic forces. Typically, the contribution from these forces must be removed before the results of the experiment can be successfully interpreted, often by comparison to density functional theory calculations. In this paper we compare the ‘on-minus-off’ method for extracting site-specific forces to a commonly used extrapolation method modelling the long-range forces using a simple power law. By examining the behaviour of the fitting method in the case of two radically different interaction potentials we show that significant uncertainties in the final extracted forces may result from use of the extrapolation method.

  19. From static to animated: Measuring mechanical forces in tissues.

    Science.gov (United States)

    Nelson, Celeste M

    2017-01-02

    Cells are physical objects that exert mechanical forces on their surroundings as they migrate and take their places within tissues. New techniques are now poised to enable the measurement of cell-generated mechanical forces in intact tissues in vivo, which will illuminate the secret dynamic lives of cells and change our current perception of cell biology. © 2017 Nelson.

  20. Reduction of Liquid Bridge Force for 3D Microstructure Measurements

    Directory of Open Access Journals (Sweden)

    Hiroshi Murakami

    2016-05-01

    Full Text Available Recent years have witnessed an increased demand for a method for precise measurement of the microstructures of mechanical microparts, microelectromechanical systems, micromolds, optical devices, microholes, etc. This paper presents a measurement system for three-dimensional (3D microstructures that use an optical fiber probe. This probe consists of a stylus shaft with a diameter of 2.5 µm and a glass ball with a diameter of 5 µm attached to the stylus tip. In this study, the measurement system, placed in a vacuum vessel, is constructed suitably to prevent adhesion of the stylus tip to the measured surface caused by the surface force resulting from the van der Waals force, electrostatic force, and liquid bridge force. First, these surface forces are analyzed with the aim of investigating the causes of adhesion. Subsequently, the effects of pressure inside the vacuum vessel on surface forces are evaluated. As a result, it is found that the surface force is 0.13 µN when the pressure inside the vacuum vessel is 350 Pa. This effect is equivalent to a 60% reduction in the surface force in the atmosphere.

  1. Vehicle lateral state estimation based on measured tyre forces.

    Science.gov (United States)

    Tuononen, Ari J

    2009-01-01

    Future active safety systems need more accurate information about the state of vehicles. This article proposes a method to evaluate the lateral state of a vehicle based on measured tyre forces. The tyre forces of two tyres are estimated from optically measured tyre carcass deflections and transmitted wirelessly to the vehicle body. The two remaining tyres are so-called virtual tyre sensors, the forces of which are calculated from the real tyre sensor estimates. The Kalman filter estimator for lateral vehicle state based on measured tyre forces is presented, together with a simple method to define adaptive measurement error covariance depending on the driving condition of the vehicle. The estimated yaw rate and lateral velocity are compared with the validation sensor measurements.

  2. Vehicle Lateral State Estimation Based on Measured Tyre Forces

    Directory of Open Access Journals (Sweden)

    Ari J. Tuononen

    2009-10-01

    Full Text Available Future active safety systems need more accurate information about the state of vehicles. This article proposes a method to evaluate the lateral state of a vehicle based on measured tyre forces. The tyre forces of two tyres are estimated from optically measured tyre carcass deflections and transmitted wirelessly to the vehicle body. The two remaining tyres are so-called virtual tyre sensors, the forces of which are calculated from the real tyre sensor estimates. The Kalman filter estimator for lateral vehicle state based on measured tyre forces is presented, together with a simple method to define adaptive measurement error covariance depending on the driving condition of the vehicle. The estimated yaw rate and lateral velocity are compared with the validation sensor measurements.

  3. [Identification from bite marks].

    Science.gov (United States)

    Schulz, P

    1980-02-01

    Criteria to be considered for establishing the guilt or innocence of a possible offender on the basis of bite marks on the skin of the murder victim were presented using four analyses of bite marks on murder victims. The bite marks must be identifiable; a clear 1:1 photograph should be made which is then compared with impression of a model of the suspect's bite. These impressions are made with graphite on, for example, the surface of a balloon or modelling clay. The evidence provided by a distinct bite mark is almost as conclusive as a fingerprint. Using only the bite mark photographs, the forensic-stomatologic evaluation influenced the course of argumentation in the legal proceedings of three of the four cases discussed; the evaluation was central for the proceedings in one case.

  4. Measuring Air Force Contracting Customer Satisfaction

    Science.gov (United States)

    2015-12-01

    customer satisfaction is through the use of the EDP model , and then assesses the value and importance of measuring customer satisfaction through the lens...companies’ business models . Their companies’ business models dictated the frequency for collecting customer satisfaction data by encouraging regular...pursuit of satisfying their organizations’ business models , the participants aligned the frequency for collecting customer satisfaction

  5. Bite Mark Analysis

    OpenAIRE

    SK Padmakumar; VT Beena; N Salmanulfaris; Ashith B Acharya; G Indu; Sajai J Kumar

    2014-01-01

    Bite mark analysis plays an important role in personal identi- fi cation in forensic odontology. They are commonly seen in violent crimes such as sexual assaults, homicides, child abuse, etc. Human bites are common on the face and are usually seen on prominent locations of the face such as the ears, nose and lips. Individual characteristics recorded in the bite marks such as fractures, rotations, attrition, and congenital malformations are helpful in identifying the in...

  6. Maximal bite force in young adults with temporomandibular disorders and bruxism Força de mordida máxima em adultos jovens com disfunção temporomandibular e bruxismo

    Directory of Open Access Journals (Sweden)

    Raquel Aparecida Pizolato

    2007-09-01

    Full Text Available Parafunctional habits, such as bruxism, are contributory factors for temporomandibular disorders (TMD. The aim of this study was to evaluate the maximal bite force (MBF in the presence of TMD and bruxism (TMDB in young adults. Twelve women (mean age 21.5 years and 7 men (mean age 22.4 years, composed the TMDB group. Ten healthy women and 9 men (mean age 21.4 and 22.4 years, respectively formed the control group. TMD symptoms were evaluated by a structured questionnaire and clinical signs/symptoms were evaluated during clinical examination. A visual analogical scale (VAS was applied for stress assessment. MBF was measured with a gnatodynamometer. The subjects were asked to bite 2 times with maximal effort, during 5 seconds, with a rest interval of about one minute. The highest values were considered. The data were analyzed with Shapiro-Wilks W-test, descriptive statistics, paired or unpaired t tests or Mann-Whitney tests when indicated, and Fisher's exact test (p Hábitos parafuncionais, como o bruxismo, podem contribuir para a disfunção temporomandibular (DTM. O objetivo deste trabalho foi avaliar a força de mordida máxima (FMM na presença de DTM e bruxismo (DTMB em adultos jovens. Doze mulheres (idade média de 21,5 anos e sete homens (idade média 22,4 anos compuseram o grupo DTMB. O grupo controle foi formado por 10 mulheres e 9 homens saudáveis, com idades médias de 21,4 e 22,4 anos, respectivamente. Os sintomas de DTM foram avaliados com um questionário estruturado, e os sinais/sintomas clínicos foram avaliados no exame clínico. Para avaliar estresse, utilizou-se a escala analógica visual (VAS. A FMM foi mensurada com gnatodinamômetro, e o participante foi orientado a morder com o máximo esforço durante 5 segundos, duas vezes, com intervalo de aproximadamente 1 minuto, considerando-se os valores máximos. Os dados foram analisados pelo teste de Shapiro-Wilks, estatística descritiva, teste t pareado e independente, Mann

  7. No Biting: Policy and Practice for Toddler Programs.

    Science.gov (United States)

    Kinnell, Gretchen

    Noting that no single issue in programs for toddlers inflames parents and frustrates staff the way biting does, this book provides guidance on program policy and practice. The book is based upon discussions of a task force on biting comprised of caregivers and administrators from the child care centers and Early Head Start in Syracuse, New York,…

  8. Animal Bites of the Hand

    Science.gov (United States)

    ... bites occur in the United States each year. Dogs cause most animal bites. Other biting animals include ... elbow or in the armpit Fever Tiredness Night sweats Shakes If these develop, you should seek emergency ...

  9. Standardized voluntary force measurement in a lower extremity rehabilitation robot

    OpenAIRE

    Bolliger, M; Banz, R; Dietz, V; Lünenburger, L

    2008-01-01

    Abstract Background Isometric force measurements in the lower extremity are widely used in rehabilitation of subjects with neurological movement disorders (NMD) because walking ability has been shown to be related to muscle strength. Therefore muscle strength measurements can be used to monitor and control the effects of training programs. A new method to assess isometric muscle force was implemented in the driven gait orthosis (DGO) Lokomat. To evaluate the capabilities of this new measureme...

  10. Quantitative measurements of shear displacement using atomic force microscopy

    International Nuclear Information System (INIS)

    Wang, Wenbo; Wu, Weida; Sun, Ying; Zhao, Yonggang

    2016-01-01

    We report a method to quantitatively measure local shear deformation with high sensitivity using atomic force microscopy. The key point is to simultaneously detect both torsional and buckling motions of atomic force microscopy (AFM) cantilevers induced by the lateral piezoelectric response of the sample. This requires the quantitative calibration of torsional and buckling response of AFM. This method is validated by measuring the angular dependence of the in-plane piezoelectric response of a piece of piezoelectric α-quartz. The accurate determination of the amplitude and orientation of the in-plane piezoelectric response, without rotation, would greatly enhance the efficiency of lateral piezoelectric force microscopy.

  11. Nanonet force microscopy for measuring forces in single smooth muscle cells of the human aorta.

    Science.gov (United States)

    Hall, Alexander; Chan, Patrick; Sheets, Kevin; Apperson, Matthew; Delaughter, Christopher; Gleason, Thomas G; Phillippi, Julie A; Nain, Amrinder

    2017-07-07

    A number of innovative methods exist to measure cell-matrix adhesive forces, but they have yet to accurately describe and quantify the intricate interplay of a cell and its fibrous extracellular matrix (ECM). In cardiovascular pathologies, such as aortic aneurysm, new knowledge on the involvement of cell-matrix forces could lead to elucidation of disease mechanisms. To better understand this dynamics, we measured primary human aortic single smooth muscle cell (SMC) forces using nanonet force microscopy in both inside-out (I-O intrinsic contractility) and outside-in (O-I external perturbation) modes. For SMC populations, we measured the I-O and O-I forces to be 12.9 ± 1.0 and 57.9 ± 2.5 nN, respectively. Exposure of cells to oxidative stress conditions caused a force decrease of 57 and 48% in I-O and O-I modes, respectively, and an increase in migration rate by 2.5-fold. Finally, in O-I mode, we cyclically perturbed cells at constant strain of varying duration to simulate in vivo conditions of the cardiac cycle and found that I-O forces decrease with increasing duration and O-I forces decreased by half at shorter cycle times. Thus our findings highlight the need to study forces exerted and felt by cells simultaneously to comprehensively understand force modulation in cardiovascular disease. © 2017 Hall et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  12. Sub-Angstrom oscillation amplitude non-contact atomic force microscopy for lateral force gradient measurement

    International Nuclear Information System (INIS)

    Atabak, Mehrdad; Unverdi, Ozhan; Ozer, H. Ozguer; Oral, Ahmet

    2009-01-01

    We report the first results from novel sub-Angstrom oscillation amplitude non-contact atomic force microscopy developed for lateral force gradient measurements. Quantitative lateral force gradients between a tungsten tip and Si(1 1 1)-(7 x 7) surface can be measured using this microscope. Simultaneous lateral force gradient and scanning tunnelling microscope images of single and multi atomic steps are obtained. In our measurement, tunnel current is used as feedback. The lateral stiffness contrast has been observed to be 2.5 N/m at single atomic step, in contrast to 13 N/m at multi atomic step on Si(1 1 1) surface. We also carried out a series of lateral stiffness-distance spectroscopy. We observed lateral stiffness-distance curves exhibit sharp increase in the stiffness as the sample is approached towards the surface. We usually observed positive stiffness and sometimes going into slightly negative region.

  13. Does an instrumented treadmill correctly measure the ground reaction forces?

    Directory of Open Access Journals (Sweden)

    Patrick A. Willems

    2013-11-01

    Since the 1990s, treadmills have been equipped with multi-axis force transducers to measure the three components of the ground reaction forces during walking and running. These measurements are correctly performed if the whole treadmill (including the motor is mounted on the transducers. In this case, the acceleration of the treadmill centre of mass relative to the reference frame of the laboratory is nil. The external forces exerted on one side of the treadmill are thus equal in magnitude and opposite in direction to the external forces exerted on the other side. However, uncertainty exists about the accuracy of these measures: due to friction between the belt and the tread-surface, due to the motor pulling the belt, some believe that it is not possible to correctly measure the horizontal components of the forces exerted by the feet on the belt. Here, we propose a simple model of an instrumented treadmill and we demonstrate (1 that the forces exerted by the subject moving on the upper part of the treadmill are accurately transmitted to the transducers placed under it and (2 that all internal forces – including friction – between the parts of the treadmill are cancelling each other.

  14. Uncertainty quantification in nanomechanical measurements using the atomic force microscope

    Science.gov (United States)

    Ryan Wagner; Robert Moon; Jon Pratt; Gordon Shaw; Arvind Raman

    2011-01-01

    Quantifying uncertainty in measured properties of nanomaterials is a prerequisite for the manufacture of reliable nanoengineered materials and products. Yet, rigorous uncertainty quantification (UQ) is rarely applied for material property measurements with the atomic force microscope (AFM), a widely used instrument that can measure properties at nanometer scale...

  15. Friction force measurements relevant to de-inking by means of atomic force microscope.

    Science.gov (United States)

    Theander, Katarina; Pugh, Robert J; Rutland, Mark W

    2005-11-15

    In the pulping step of the de-inking process, the ink detaches from the fibers due to shear and physical chemical interaction. In order to get a better understanding of the forces involved between cellulose and ink, the atomic force microscope and the colloidal probe technique have been used in the presence of a model chemical dispersant (hexa-ethyleneglycol mono n-dodecyl ether, C12E6). A cellulose bead was used as the colloidal probe and three different lower surfaces have been used, an alkyd resin, mica and a cellulose sphere. The normal and lateral forces have been measured at a range of nonionic concentrations. It was found that the lateral sliding friction forces deceased with increasing surfactant concentration for both the alkyd resin and mica while no differences were observed for the cellulose surface. In addition, only a very small change in normal force could be detected for the alkyd surface as the concentration changed.

  16. Towards a Casimir Force Measurement between Micromachined Parallel Plate Structures

    Directory of Open Access Journals (Sweden)

    Remco J. Wiegerink

    2012-11-01

    Full Text Available Ever since its prediction, experimental investigation of the Casimir force has been of great scientific interest. Many research groups have successfully attempted quantifying the force with different device geometries; however, measurement of the Casimir force between parallel plates with sub-micron separation distance is still a challenging task, since it becomes extremely difficult to maintain sufficient parallelism between the plates. The Casimir force can significantly influence the operation of micro devices and to realize reliable and reproducible devices it is necessary to understand and experimentally verify the influence of the Casimir force at sub-micron scale. In this paper, we present the design principle, fabrication and characterization of micromachined parallel plate structures that could allow the measurement of the Casimir force with tunable separation distance in the range of 100 to 1000 nm. Initially, a gold coated parallel plate structure is explored to measure the Casimir force, but also other material combinations could be investigated. Using gold-silicon eutectic bonding, a reliable approach to bond chips with integrated suspended plates together with a well-defined separation distance in the order of 1–2 μm is developed.

  17. MD1405: Demonstration of forced dynamic aperture measurements at injection

    CERN Document Server

    Carlier, Felix Simon; Persson, Tobias Hakan Bjorn; Tomas Garcia, Rogelio; CERN. Geneva. ATS Department

    2017-01-01

    Accurate measurements of dynamic aperture become more important for the LHC as it advances into increasingly nonlinear regimes of operations, as well as for the High Luminosity LHC where machine nonlinearities will have a significantly larger impact. Direct dynamic aperture measurements at top energy in the LHC are challenging, and conventional single kick methods are not viable. Dynamic aperture measurements under forced oscillation of AC dipoles have been proposed as s possible alternative observable. A first demonstration of forced DA measurements at injections energy is presented.

  18. Designing an experiment to measure cellular interaction forces

    Science.gov (United States)

    McAlinden, Niall; Glass, David G.; Millington, Owain R.; Wright, Amanda J.

    2013-09-01

    Optical trapping is a powerful tool in Life Science research and is becoming common place in many microscopy laboratories and facilities. The force applied by the laser beam on the trapped object can be accurately determined allowing any external forces acting on the trapped object to be deduced. We aim to design a series of experiments that use an optical trap to measure and quantify the interaction force between immune cells. In order to cause minimum perturbation to the sample we plan to directly trap T cells and remove the need to introduce exogenous beads to the sample. This poses a series of challenges and raises questions that need to be answered in order to design a set of effect end-point experiments. A typical cell is large compared to the beads normally trapped and highly non-uniform - can we reliably trap such objects and prevent them from rolling and re-orientating? In this paper we show how a spatial light modulator can produce a triple-spot trap, as opposed to a single-spot trap, giving complete control over the object's orientation and preventing it from rolling due, for example, to Brownian motion. To use an optical trap as a force transducer to measure an external force you must first have a reliably calibrated system. The optical trapping force is typically measured using either the theory of equipartition and observing the Brownian motion of the trapped object or using an escape force method, e.g. the viscous drag force method. In this paper we examine the relationship between force and displacement, as well as measuring the maximum displacement from equilibrium position before an object falls out of the trap, hence determining the conditions under which the different calibration methods should be applied.

  19. Treatment for Animal Bites

    Science.gov (United States)

    ... find out where to take your child for treatment. If the wound is so large that the edges won’t ... above the bite Your pediatrician may recommend antibiotic therapy for a child who has: Moderate or severe bite wounds Puncture wounds, especially if the bone, tendon, or ...

  20. Rat Bite Fever

    Science.gov (United States)

    ... Español Text Size Email Print Share Rat Bite Fever Page Content Article Body Rat-bite fever is a disease that occurs in humans who ... ingestion of contaminated food or milk products (Haverhill fever). Most cases in the United States are caused ...

  1. Dog and cat bites.

    Science.gov (United States)

    Ellis, Robert; Ellis, Carrie

    2014-08-15

    Animal bites account for 1% of all emergency department visits in the United States and more than $50 million in health care costs per year. Most animal bites are from a dog, usually one known to the victim. Most dog bite victims are children. Bite wounds should be cleaned, copiously irrigated with normal saline using a 20-mL or larger syringe or a 20-gauge catheter attached to the syringe. The wound should be explored for tendon or bone involvement and possible foreign bodies. Wounds may be closed if cosmetically favorable, such as wounds on the face or gaping wounds. Antibiotic prophylaxis should be considered, especially if there is a high risk of infection, such as with cat bites, with puncture wounds, with wounds to the hand, and in persons who are immunosuppressed. Amoxicillin/clavulanate is the first-line prophylactic antibiotic. The need for rabies prophylaxis should be addressed with any animal bite because even domestic animals are often unvaccinated. Postexposure rabies prophylaxis consists of immune globulin at presentation and vaccination on days 0, 3, 7, and 14. Counseling patients and families about animal safety may help decrease animal bites. In most states, physicians are required by law to report animal bites.

  2. All about Biting

    Science.gov (United States)

    Crisalli, Linda

    2008-01-01

    As directors of early learning programs, one deals with a myriad of issues on a daily basis. One of the more frustrating things that come up from time to time is biting. Biting is particularly problematic because it tends to elicit such a strong response from caregivers, parents, and other children. In this article, the author talks about biting…

  3. Managing the Biting Child.

    Science.gov (United States)

    Claffey, Anne E.; And Others

    1994-01-01

    Discusses the causes of biting behavior and techniques that parents and educators can use to manage biting toddlers. Notes that solutions need to consider the developmental level and needs of the child, the influence of the child's environment, and the role of adults in the child's life. (MDM)

  4. Isoelectric point of fluorite by direct force measurements using atomic force microscopy.

    Science.gov (United States)

    Assemi, Shoeleh; Nalaskowski, Jakub; Miller, Jan D; Johnson, William P

    2006-02-14

    Interaction forces between a fluorite (CaF2) surface and colloidal silica were measured by atomic force microscopy (AFM) in 1 x 10(-3) M NaNO3 at different pH values. Forces between the silica colloid and fluorite flat were measured at a range of pH values above the isoelectric point (IEP) of silica so that the forces were mainly controlled by the fluorite surface charge. In this way, the IEP of the fluorite surface was deduced from AFM force curves at pH approximately 9.2. Experimental force versus separation distance curves were in good agreement with theoretical predictions based on long-range electrostatic interactions, allowing the potential of the fluorite surface to be estimated from the experimental force curves. AFM-deduced surface potentials were generally lower than the published zeta potentials obtained from electrokinetic methods for powdered samples. Differences in methodology, orientation of the fluorite, surface carbonation, and equilibration time all could have contributed to this difference.

  5. Error rates in bite mark analysis in an in vivo animal model.

    Science.gov (United States)

    Avon, S L; Victor, C; Mayhall, J T; Wood, R E

    2010-09-10

    Recent judicial decisions have specified that one foundation of reliability of comparative forensic disciplines is description of both scientific approach used and calculation of error rates in determining the reliability of an expert opinion. Thirty volunteers were recruited for the analysis of dermal bite marks made using a previously established in vivo porcine-skin model. Ten participants were recruited from three separate groups: dentists with no experience in forensics, dentists with an interest in forensic odontology, and board-certified diplomates of the American Board of Forensic Odontology (ABFO). Examiner demographics and measures of experience in bite mark analysis were collected for each volunteer. Each participant received 18 completely documented, simulated in vivo porcine bite mark cases and three paired sets of human dental models. The paired maxillary and mandibular models were identified as suspect A, suspect B, and suspect C. Examiners were tasked to determine, using an analytic method of their own choosing, whether each bite mark of the 18 bite mark cases provided was attributable to any of the suspect dentitions provided. Their findings were recorded on a standardized recording form. The results of the study demonstrated that the group of inexperienced examiners often performed as well as the board-certified group, and both inexperienced and board-certified groups performed better than those with an interest in forensic odontology that had not yet received board certification. Incorrect suspect attributions (possible false inculpation) were most common among this intermediate group. Error rates were calculated for each of the three observer groups for each of the three suspect dentitions. This study demonstrates that error rates can be calculated using an animal model for human dermal bite marks, and although clinical experience is useful, other factors may be responsible for accuracy in bite mark analysis. Further, this study demonstrates

  6. Support force measures of midsized men in seated positions.

    Science.gov (United States)

    Bush, Tamara Reid; Hubbard, Robert P

    2007-02-01

    Two areas not well researched in the field of seating mechanics are the distribution of normal and shear forces, and how those forces change with seat position. The availability of these data would be beneficial for the design and development of office, automotive and medical seats. To increase our knowledge in the area of seating mechanics, this study sought to measure the normal and shear loads applied to segmental supports in 12 seated positions, utilizing three inclination angles and four levels of seat back articulation that were associated with automotive driving positions. Force data from six regions, including the thorax, sacral region, buttocks, thighs, feet, and hand support were gathered using multi-axis load cells. The sample contained 23 midsized subjects with an average weight of 76.7 kg and a standard deviation of 4.2 kg, and an average height of 1745 mm with a standard deviation of 19 mm. Results were examined in terms of seat back inclination and in terms of torso articulation for relationships between seat positions and support forces. Using a repeated measures analysis, significant differences (p<0.05) were identified for normal forces relative to all inclination angles except for forces occurring at the hand support. Other significant differences were observed between normal forces behind the buttocks, pelvis, and feet for torso articulations. Significant differences in the shear forces occurred under the buttocks and posterior pelvis during changes in seat back inclination. Significant differences in shear forces were also identified for torso articulations. These data suggest that as seat back inclination or torso articulation change, significant shifts in force distribution occur.

  7. Fiber optic micro sensor for the measurement of tendon forces.

    Science.gov (United States)

    Behrmann, Gregory P; Hidler, Joseph; Mirotznik, Mark S

    2012-10-03

    A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housings were fabricated by several methods including laser micromachining, swaging, and hydroforming. Designs are presented that allow for simultaneous temperature and force measurements as well as for simultaneous resolution of multi-axis forces.The sensor was experimentally evaluated by hydrostatic loading and in vitro testing. A commercial hydraulic burst tester was used to provide uniform pressures on the sensor in order to establish the linearity, repeatability, and accuracy characteristics of the sensor. The in vitro experiments were performed in excised tendon and in a dynamic gait simulator to simulate biological conditions. In both experimental conditions, the sensor was found to be a sensitive and reliable method for acquiring minimally invasive measurements of soft tissue forces. Our results suggest that this sensor will prove useful in a variety of biomechanical measurements.

  8. Fiber optic micro sensor for the measurement of tendon forces

    Directory of Open Access Journals (Sweden)

    Behrmann Gregory P

    2012-10-01

    Full Text Available Abstract A fiber optic sensor developed for the measurement of tendon forces was designed, numerically modeled, fabricated, and experimentally evaluated. The sensor incorporated fiber Bragg gratings and micro-fabricated stainless steel housings. A fiber Bragg grating is an optical device that is spectrally sensitive to axial strain. Stainless steel housings were designed to convert radial forces applied to the housing into axial forces that could be sensed by the fiber Bragg grating. The metal housings were fabricated by several methods including laser micromachining, swaging, and hydroforming. Designs are presented that allow for simultaneous temperature and force measurements as well as for simultaneous resolution of multi-axis forces. The sensor was experimentally evaluated by hydrostatic loading and in vitro testing. A commercial hydraulic burst tester was used to provide uniform pressures on the sensor in order to establish the linearity, repeatability, and accuracy characteristics of the sensor. The in vitro experiments were performed in excised tendon and in a dynamic gait simulator to simulate biological conditions. In both experimental conditions, the sensor was found to be a sensitive and reliable method for acquiring minimally invasive measurements of soft tissue forces. Our results suggest that this sensor will prove useful in a variety of biomechanical measurements.

  9. Extending Bell's model: how force transducer stiffness alters measured unbinding forces and kinetics of molecular complexes.

    Science.gov (United States)

    Walton, Emily B; Lee, Sunyoung; Van Vliet, Krystyn J

    2008-04-01

    Forced unbinding of complementary macromolecules such as ligand-receptor complexes can reveal energetic and kinetic details governing physiological processes ranging from cellular adhesion to drug metabolism. Although molecular-level experiments have enabled sampling of individual ligand-receptor complex dissociation events, disparities in measured unbinding force F(R) among these methods lead to marked variation in inferred binding energetics and kinetics at equilibrium. These discrepancies are documented for even the ubiquitous ligand-receptor pair, biotin-streptavidin. We investigated these disparities and examined atomic-level unbinding trajectories via steered molecular dynamics simulations, as well as via molecular force spectroscopy experiments on biotin-streptavidin. In addition to the well-known loading rate dependence of F(R) predicted by Bell's model, we find that experimentally accessible parameters such as the effective stiffness of the force transducer k can significantly perturb the energy landscape and the apparent unbinding force of the complex for sufficiently stiff force transducers. Additionally, at least 20% variation in unbinding force can be attributed to minute differences in initial atomic positions among energetically and structurally comparable complexes. For force transducers typical of molecular force spectroscopy experiments and atomistic simulations, this energy barrier perturbation results in extrapolated energetic and kinetic parameters of the complex that depend strongly on k. We present a model that explicitly includes the effect of k on apparent unbinding force of the ligand-receptor complex, and demonstrate that this correction enables prediction of unbinding distances and dissociation rates that are decoupled from the stiffness of actual or simulated molecular linkers.

  10. Magnetic moment measurement of magnetic nanoparticles using atomic force microscopy

    International Nuclear Information System (INIS)

    Park, J-W; Lee, E-C; Ju, H; Yoo, I S; Chang, W-S; Chung, B H; Kim, B S

    2008-01-01

    Magnetic moment per unit mass of magnetic nanoparticles was found by using the atomic force microscope (AFM). The mass of the nanoparticles was acquired from the resonance frequency shift of the particle-attached AFM probe and magnetic force measurement was also carried out with the AFM. Combining with magnetic field strength, the magnetic moment per unit mass of the nanoparticles was determined as a function of magnetic field strength. (technical design note)

  11. Field measurement of basal forces generated by erosive debris flows

    Science.gov (United States)

    McCoy, S.W.; Tucker, G.E.; Kean, J.W.; Coe, J.A.

    2013-01-01

    It has been proposed that debris flows cut bedrock valleys in steeplands worldwide, but field measurements needed to constrain mechanistic models of this process remain sparse due to the difficulty of instrumenting natural flows. Here we present and analyze measurements made using an automated sensor network, erosion bolts, and a 15.24 cm by 15.24 cm force plate installed in the bedrock channel floor of a steep catchment. These measurements allow us to quantify the distribution of basal forces from natural debris‒flow events that incised bedrock. Over the 4 year monitoring period, 11 debris‒flow events scoured the bedrock channel floor. No clear water flows were observed. Measurements of erosion bolts at the beginning and end of the study indicated that the bedrock channel floor was lowered by 36 to 64 mm. The basal force during these erosive debris‒flow events had a large‒magnitude (up to 21 kN, which was approximately 50 times larger than the concurrent time‒averaged mean force), high‒frequency (greater than 1 Hz) fluctuating component. We interpret these fluctuations as flow particles impacting the bed. The resulting variability in force magnitude increased linearly with the time‒averaged mean basal force. Probability density functions of basal normal forces were consistent with a generalized Pareto distribution, rather than the exponential distribution that is commonly found in experimental and simulated monodispersed granular flows and which has a lower probability of large forces. When the bed sediment thickness covering the force plate was greater than ~ 20 times the median bed sediment grain size, no significant fluctuations about the time‒averaged mean force were measured, indicating that a thin layer of sediment (~ 5 cm in the monitored cases) can effectively shield the subjacent bed from erosive impacts. Coarse‒grained granular surges and water‒rich, intersurge flow had very similar basal force distributions despite

  12. Cantilever contribution to the total electrostatic force measured with the atomic force microscope

    International Nuclear Information System (INIS)

    Guriyanova, Svetlana; Golovko, Dmytro S; Bonaccurso, Elmar

    2010-01-01

    The atomic force microscope (AFM) is a powerful tool for surface imaging at the nanometer scale and surface force measurements in the piconewton range. Among long-range surface forces, the electrostatic forces play a predominant role. They originate if the electric potentials of the substrate and of the tip of the AFM cantilever are different. A quantitative interpretation of the AFM signal is often difficult because it depends in a complicated fashion on the cantilever–tip–surface geometry. Since the electrostatic interaction is a long-range interaction, the cantilever, which is many microns from the surface, contributes to the total electrostatic force along with the tip. Here we present results of the electrostatic interaction between a conducting flat surface and horizontal or tilted cantilevers, with and without tips, at various distances from the surface. As addressed in a previous work, we show that the contribution of the cantilever to the overall force cannot be neglected. Based on a predictive model and on 3D confocal measurements, we discuss the influence of the tilting angle of the cantilever

  13. Electron "bite-outs" in Dusty Plasmas

    Science.gov (United States)

    Horanyi, M.; Hsu, S.; Kempf, S.

    2012-12-01

    The study of dusty plasmas is still an emerging new field that bridges a number of traditionally separate subjects, including for example, celestial mechanics, and plasma physics. Dust particles immersed in plasmas and UV radiation collect electrostatic charges and respond to electromagnetic forces in addition to all the other forces acting on uncharged grains. Simultaneously, dust can alter its plasma environment. Dust particles in plasmas are unusual charge carriers. They are many orders of magnitude heavier than any other plasma particles, and they can have many orders of magnitude larger (negative or positive) time-dependent charges. Dust particles can communicate non-electromagnetic effects (gravity, drag, radiation pressure) to the plasma that can represent new free energy sources. Their presence can influence the collective plasma behavior, for example, by altering the traditional plasma wave modes and by triggering new types of waves and instabilities. Dusty plasmas represent the most general form of space, laboratory, and industrial plasmas. Interplanetary space, comets, planetary rings, asteroids, the Moon, aerosols in the atmosphere, are all examples where electrons, ions, and dust particles coexist. This talk will focus on "electron bite-outs", the apparent reduction of the electron density due to dust charging in a plasma comprised of electrons, ions and dust particles We will compare the recent observations of the plasma conditions near Enceladus at Saturn to the decades old measurements in the Earth's mesosphere. We present model calculations of dust charging in a region where plasma is maintained by UV radiation, and present the time-dependent charge distribution of grains as function of dust density and size distribution. We will also make estimates for possible dusty plasma wave activities as function of the magnitude of the electron "bite-outs".

  14. Accurate fluid force measurement based on control surface integration

    Science.gov (United States)

    Lentink, David

    2018-01-01

    Nonintrusive 3D fluid force measurements are still challenging to conduct accurately for freely moving animals, vehicles, and deforming objects. Two techniques, 3D particle image velocimetry (PIV) and a new technique, the aerodynamic force platform (AFP), address this. Both rely on the control volume integral for momentum; whereas PIV requires numerical integration of flow fields, the AFP performs the integration mechanically based on rigid walls that form the control surface. The accuracy of both PIV and AFP measurements based on the control surface integration is thought to hinge on determining the unsteady body force associated with the acceleration of the volume of displaced fluid. Here, I introduce a set of non-dimensional error ratios to show which fluid and body parameters make the error negligible. The unsteady body force is insignificant in all conditions where the average density of the body is much greater than the density of the fluid, e.g., in gas. Whenever a strongly deforming body experiences significant buoyancy and acceleration, the error is significant. Remarkably, this error can be entirely corrected for with an exact factor provided that the body has a sufficiently homogenous density or acceleration distribution, which is common in liquids. The correction factor for omitting the unsteady body force, {{{ {ρ f}} {1 - {ρ f} ( {{ρ b}+{ρ f}} )}.{( {{{{ρ }}b}+{ρ f}} )}}} , depends only on the fluid, {ρ f}, and body, {{ρ }}b, density. Whereas these straightforward solutions work even at the liquid-gas interface in a significant number of cases, they do not work for generalized bodies undergoing buoyancy in combination with appreciable body density inhomogeneity, volume change (PIV), or volume rate-of-change (PIV and AFP). In these less common cases, the 3D body shape needs to be measured and resolved in time and space to estimate the unsteady body force. The analysis shows that accounting for the unsteady body force is straightforward to non

  15. Global estimate of aerosol direct radiative forcing from satellite measurements.

    Science.gov (United States)

    Bellouin, Nicolas; Boucher, Olivier; Haywood, Jim; Reddy, M Shekar

    2005-12-22

    Atmospheric aerosols cause scattering and absorption of incoming solar radiation. Additional anthropogenic aerosols released into the atmosphere thus exert a direct radiative forcing on the climate system. The degree of present-day aerosol forcing is estimated from global models that incorporate a representation of the aerosol cycles. Although the models are compared and validated against observations, these estimates remain uncertain. Previous satellite measurements of the direct effect of aerosols contained limited information about aerosol type, and were confined to oceans only. Here we use state-of-the-art satellite-based measurements of aerosols and surface wind speed to estimate the clear-sky direct radiative forcing for 2002, incorporating measurements over land and ocean. We use a Monte Carlo approach to account for uncertainties in aerosol measurements and in the algorithm used. Probability density functions obtained for the direct radiative forcing at the top of the atmosphere give a clear-sky, global, annual average of -1.9 W m(-2) with standard deviation, +/- 0.3 W m(-2). These results suggest that present-day direct radiative forcing is stronger than present model estimates, implying future atmospheric warming greater than is presently predicted, as aerosol emissions continue to decline.

  16. Understanding and Preventing Toddler Biting.

    Science.gov (United States)

    Garcia, Veronica

    1999-01-01

    Discusses the problem of toddler biting behavior in child care settings. Describes reasons for biting by toddlers, recommends caregiver responses to toddler biting, presents tips for observing children to identify the biter's patterns, and outlines ways to prevent biting in child care settings. (KB)

  17. The application of force-sensing resistor sensors for measuring forces developed by the human hand.

    Science.gov (United States)

    Nikonovas, A; Harrison, A J L; Hoult, S; Sammut, D

    2004-01-01

    Most attempts to measure forces developed by the human hand have been implemented by placing force sensors on the object of interaction. Other researchers have placed sensors just on the subject's fingertips. In this paper, a system is described that measures forces over the entire hand using thin-film sensors and associated electronics. This system was developed by the authors and is able to obtain force readings from up to 60 thin-film sensors at rates of up to 400 samples/s per sensor. The sensors can be placed anywhere on the palm and/or fingers of the hand. The sensor readings, together with a video stream containing information about hand posture, are logged into a portable computer using a multiplexer, analogue-to-digital converter and software developed for the purpose. The system has been successfully used to measure forces involved in a range of everyday tasks such as driving a vehicle, lifting saucepans and hitting a golf ball. In the latter case, results are compared with those from an instrumented golf club. Future applications include the assessment of hand strength following disease, trauma or surgery, and to enable quantitative ergonomic investigations.

  18. Reducing detrimental electrostatic effects in Casimir-force measurements and Casimir-force-based microdevices

    Science.gov (United States)

    Xu, Jun; Klimchitskaya, G. L.; Mostepanenko, V. M.; Mohideen, U.

    2018-03-01

    It is well known that residual electrostatic forces create significant difficulties in precise measurements of the Casimir force and the wide use of Casimir-operated microdevices. We experimentally demonstrate that, with the help of Ar-ion cleaning of the surfaces, it is possible to make electrostatic effects negligibly small compared to the Casimir interaction. Our experimental setup consists of a dynamic atomic force microscope supplemented with an Ar-ion gun and argon reservoir. The residual potential difference between the Au-coated surfaces of a sphere and those of a plate was measured both before and after in situ Ar-ion cleaning. It is shown that this cleaning decreases the magnitude of the residual potential by up to an order of magnitude and makes it almost independent of the separation. The gradient of the Casimir force was measured using ordinary samples subjected to Ar-ion cleaning. The obtained results are shown to be in good agreement both with previous precision measurements using specially selected samples and with theoretical predictions of the Lifshitz theory. The conclusion is made that the suggested method of in situ Ar-ion cleaning is effective in reducing the electrostatic effects and therefore is a great resource for experiments on measuring the Casimir interaction and for Casimir-operated microdevices.

  19. Measuring of beat up force on weaving machines

    Directory of Open Access Journals (Sweden)

    Bílek Martin

    2017-01-01

    Full Text Available The textile material (warp is stressed cyclically at a relative high frequency during the weaving process. Therefore, the special measuring device for analysis of beat up force in the textile material during the weaving process, has been devised in the Weaving Laboratory of the TUL. This paper includes a description of this measuring device. The experimental part includes measurements results for various materials (PES and VS and various warp thread densities of the produced fabric.

  20. A laboratory apparatus to measure clast-bed contact forces

    Science.gov (United States)

    Cohen, D.

    2007-12-01

    Glacier dynamics, sediment transport, and erosion are controlled in part by processes occurring at the interface between basal ice and bedrock. One critical parameter is the contact force between a clast and the bedrock. This force affects many processes such as basal friction which regulates sliding speed, slip resistance which influences basal shear stress and may cause micro-seismic events associated with slip instabilities, abrasion which controls rates of erosion, landscape evolution, and production of sediments. Despite field and laboratory evidences indicating that contact forces may be up to one order of magnitude higher than estimated from leading theories, no studies have yet measured with precision the magnitude of contact forces and how contact forces vary as a function of key glaciological variables such as basal melt rate and effective pressure. An apparatus was designed to make two independent measurements: (1) the contact force between a clast and a hard bed as a function of melt rate and effective pressure; (2) the drag force on an identical clast away from the bed as a function of the ice speed. The contact force differs from the drag force because of the presence of the bed which modifies the ice flow field. Measurement (2) is necessary to estimate the rheological properties of the ice and to quantify wall- (bed) effects on the drag force. The apparatus consists of a hydraulic press that pressurizes an ice cylinder, 24~cm high and 20~cm in diameter, to 1.0 - 1.5~MPa. The ice cylinder is contained inside a polycarbonate vessel. Above and below the ice cylinder are three disks: an aluminum disk sandwiched between two Delrin disks. The aluminum disks are hollow and used to circulate a fluid at a controlled temperature. The Delrin disks are used to isolate the ice from the cold room and to control the flow of heat to the ice block. The ice is kept at the melting temperature by circulating a fluid in channels inside the polycarbonate vessel and in the

  1. Standardized voluntary force measurement in a lower extremity rehabilitation robot.

    Science.gov (United States)

    Bolliger, Marc; Banz, Raphael; Dietz, Volker; Lünenburger, Lars

    2008-10-28

    Isometric force measurements in the lower extremity are widely used in rehabilitation of subjects with neurological movement disorders (NMD) because walking ability has been shown to be related to muscle strength. Therefore muscle strength measurements can be used to monitor and control the effects of training programs. A new method to assess isometric muscle force was implemented in the driven gait orthosis (DGO) Lokomat. To evaluate the capabilities of this new measurement method, inter- and intra-rater reliability were assessed. Reliability was assessed in subjects with and without NMD. Subjects were tested twice on the same day by two different therapists to test inter-rater reliability and on two separate days by the same therapist to test intra-rater reliability. Results showed fair to good reliability for the new measurement method to assess isometric muscle force of lower extremities. In subjects without NMD, intraclass correlation coefficients (ICC) for inter-rater reliability ranged from 0.72 to 0.97 and intra-rater reliability from 0.71 to 0.90. In subjects with NMD, ICC ranged from 0.66 to 0.97 for inter-rater and from 0.50 to 0.96 for intra-rater reliability. Inter- and intra- rater reliability of an assessment method for measuring maximal voluntary isometric muscle force of lower extremities was demonstrated. We suggest that this method is a valuable tool for documentation and controlling of the rehabilitation process in patients using a DGO.

  2. Spider Bites (For Parents)

    Science.gov (United States)

    ... body rash fever and chills fatigue Of a black widow spider bite: rigid, painful muscles within 8 hours no ... child was bitten by a brown recluse or black widow spider Think Prevention! Make sure garages, attics, and woodpiles ...

  3. Fire Ant Bites

    Science.gov (United States)

    ... Favorite Name: Category: Share: Yes No, Keep Private Fire Ant Bites Share | Fire ants are aggressive, venomous insects that have pinching ... across the United States, even into Puerto Rico. Fire ant stings usually occur on the feet or ...

  4. Rat-bite fever

    Science.gov (United States)

    Streptobacillary fever; Streptobacillosis; Haverhill fever; Epidemic arthritic erythema; Spirillary fever; Sodoku ... Rat-bite fever can be caused by either of 2 different bacteria, Streptobacillus moniliformis or Spirillum minus. Both of these are ...

  5. Direct Measurement of Interparticle Forces of Titan Aerosol Analogs ("Tholin") Using Atomic Force Microscopy

    Science.gov (United States)

    Yu, Xinting; Hörst, Sarah M.; He, Chao; McGuiggan, Patricia; Bridges, Nathan T.

    2017-12-01

    To understand the origin of the dunes on Titan, it is important to investigate the material properties of Titan's organic sand particles on Titan. The organic sand may behave distinctively compared to the quartz/basaltic sand on terrestrial planets (Earth, Venus, and Mars) due to differences in interparticle forces. We measured the surface energy (through contact angle measurements) and elastic modulus (through Atomic Force Microscopy) of the Titan aerosol analog (tholin). We find that the surface energy of a tholin thin film is about 70.9 mN/m, and its elastic modulus is about 3.0 GPa (similar to hard polymers like PMMA and polystyrene). For two 20 μm diameter particles, the theoretical cohesion force is therefore 3.3 μN. We directly measured interparticle forces for relevant materials: tholin particles are 0.8 ± 0.6 μN, while the interparticle cohesion between walnut shell particles (a typical model materials for the Titan Wind Tunnel, TWT) is only 0.4 ± 0.1 μN. The interparticle cohesion forces are much larger for tholins and presumably Titan sand particles than materials used in the TWT. This suggests that we should increase the interparticle force in both analog experiments (TWT) and threshold models to correctly translate the results to real Titan conditions. The strong cohesion of tholins may also inform us how the small aerosol particles (˜1 μm) in Titan's atmosphere are transformed into large sand particles (˜200 μm). It may also support the cohesive sand formation mechanism suggested by Rubin and Hesp (2009), where only unidirectional wind is needed to form linear dunes on Titan.

  6. Performance measures for combat-ready forces in the military

    CSIR Research Space (South Africa)

    Engelbrecht, GN

    2009-09-01

    Full Text Available The development of performance indicators in the military is dependent on the measurability of its associated strategies. Von Clausewitz (1976) argues that nations are either at war or preparing for war. It follows that military forces should have a...

  7. Model Engine Performance Measurement From Force Balance Instrumentation

    Science.gov (United States)

    Jeracki, Robert J.

    1998-01-01

    A large scale model representative of a low-noise, high bypass ratio turbofan engine was tested for acoustics and performance in the NASA Lewis 9- by 15-Foot Low-Speed Wind Tunnel. This test was part of NASA's continuing Advanced Subsonic Technology Noise Reduction Program. The low tip speed fan, nacelle, and an un-powered core passage (with core inlet guide vanes) were simulated. The fan blades and hub are mounted on a rotating thrust and torque balance. The nacelle, bypass duct stators, and core passage are attached to a six component force balance. The two balance forces, when corrected for internal pressure tares, measure the total thrust-minus-drag of the engine simulator. Corrected for scaling and other effects, it is basically the same force that the engine supports would feel, operating at similar conditions. A control volume is shown and discussed, identifying the various force components of the engine simulator thrust and definitions of net thrust. Several wind tunnel runs with nearly the same hardware installed are compared, to identify the repeatability of the measured thrust-minus-drag. Other wind tunnel runs, with hardware changes that affected fan performance, are compared to the baseline configuration, and the thrust and torque effects are shown. Finally, a thrust comparison between the force balance and nozzle gross thrust methods is shown, and both yield very similar results.

  8. Enclosed Electronic System for Force Measurements in Knee Implants

    Directory of Open Access Journals (Sweden)

    David Forchelet

    2014-08-01

    Full Text Available Total knee arthroplasty is a widely performed surgical technique. Soft tissue force balancing during the operation relies strongly on the experience of the surgeon in equilibrating tension in the collateral ligaments. Little information on the forces in the implanted prosthesis is available during surgery and post-operative treatment. This paper presents the design, fabrication and testing of an instrumented insert performing force measurements in a knee prosthesis. The insert contains a closed structure composed of printed circuit boards and incorporates a microfabricated polyimide thin-film piezoresistive strain sensor for each condylar compartment. The sensor is tested in a mechanical knee simulator that mimics in-vivo conditions. For characterization purposes, static and dynamic load patterns are applied to the instrumented insert. Results show that the sensors are able to measure forces up to 1.5 times body weight with a sensitivity fitting the requirements for the proposed use. Dynamic testing of the insert shows a good tracking of slow and fast changing forces in the knee prosthesis by the sensors.

  9. Molar Intrusion in Open-bite Adults Using Zygomatic Miniplates.

    Science.gov (United States)

    Marzouk, Eiman S; Abdallah, Essam Mohamed; El-Kenany, Walid A

    2015-01-01

    The aim of this study is to evaluate the skeletal, dental and soft tissue changes that arise after intrusion of the maxillary molars using zygomatic miniplates in adult skeletal anterior open bite patients. In addition to measuring the amount and rate of molar intrusion; with special emphasis on changes in the axial inclination of the intruded molars. The study group was composed of 13 anterior open bite patients (mean age 18 years, 8 months ± 2 years, 2 months) with posterior dentoalveolar excess. Mini-plates were placed in the zygomatic buttress bilaterally. The upper arch was segmentally leveled and a double Trans-Palatal Arch (TPA) was bonded. Closed NiTi coil spring was placed bilaterally between the book of the mini-plate just mesial and distal to the first molar buccal tube applying intrusive force of 450 gper side. Lateral and posteroanterior cephalograms were taken before intrusion (T1: post upper segmental leveling) and after intrusion (T2). Comparison between means before and after the intrusion was done using Wilcoxon Signed Ranks test (WSRT). Mandibular autorotation followed the molar intrusion, SNB and SN-Pog angles significantly increased while the ANB, MP-SN angle and N-S-Gn angle significantly decreased. The mean amount of accomplished molar intrusion was 3.1mm ± 0.74mm, with a rate of 0.36mm per month ± 0.08mm per month and a bite closure of 6.55mm ± 1.83mm. There was no significant buccal tip in the right and left molars upon intrusion. Conclusion: Miniplates zygomatic anchorage can be used effectively for skeletal open bite correction through posterior dento-alveolar intrusion. Intrusion of the posterior teeth with skeletal anchorage induced counterclockwise rotation of the mandible and, as a consequence, corrected the anteroposterior intermaxillary relationship with a dramatic improvement in the facial soft tissue convexity.

  10. Measuring Industry Coagglomeration and Identifying the Driving Forces

    DEFF Research Database (Denmark)

    Howard, Emma; Newman, Carol; Tarp, Finn

    2015-01-01

    Understanding industry agglomeration and its driving forces is critical for the formulation of industrial policy in developing countries. Crucial to this process is the definition and measurement of agglomeration. We construct a new coagglomeration index based purely on the location of firms. We...... examine what this index reveals about the importance of transport costs, labour market pooling and technology transfer for agglomeration processes, controlling for overall industry agglomeration. We compare the results based on our new measure to existing measures in the literature and find very different...... underlying stories at work. We conclude that in conducting analyses of this kind giving consideration to the source of agglomeration economies, employees or entrepreneurs, and finding an appropriate measure for agglomeration, are both crucial to the process of identifying agglomerative forces....

  11. Effect of permanent-magnet irregularities in levitation force measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. [Energy Technology Division, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2000-06-01

    In the measurement of the levitation force between a vertically magnetized permanent magnet (PM) and a bulk high-temperature superconductor (HTS), PM domains with horizontal components of magnetization are shown to produce a non-negligible contribution to the levitation force in most systems. Such domains are typically found in all PMs, even in those that exhibit zero net horizontal magnetic moment. Extension of this analysis leads to an HTS analogue of Earnshaw's theorem, in which the vertical stiffness is equal to the sum of the horizontal stiffness at the field-cooling position, independent of the angular distribution of magnetic moments within the PM. (author)

  12. Friction of ice measured using lateral force microscopy

    International Nuclear Information System (INIS)

    Bluhm, Hendrik; Inoue, Takahito; Salmeron, Miquel

    2000-01-01

    The friction of nanometer thin ice films grown on mica substrates is investigated using atomic force microscopy (AFM). Friction was found to be of similar magnitude as the static friction of ice reported in macroscopic experiments. The possible existence of a lubricating film of water due to pressure melting, frictional heating, and surface premelting is discussed based on the experimental results using noncontact, contact, and lateral force microscopy. We conclude that AFM measures the dry friction of ice due to the low scan speed and the squeezing out of the water layer between the sharp AFM tip and the ice surface. (c) 2000 The American Physical Society

  13. WP/084 Measuring Industry Agglomeration and Identifying the Driving Forces

    DEFF Research Database (Denmark)

    Howard, Emma; Tarp, Finn; Newman, Carol

    Understanding industry agglomeration and its driving forces is critical for the formulation of industrial policy in developing countries. Crucial to this process is the definition and measurement of agglomeration. We propose a new measure and examine what it reveals about the importance...... of transport costs, labour market pooling, and technology transfer for agglomeration processes. We contrast this analysis with insights from existing measures in the literature and find very different underlying stories at work. An exceptionally rich set of data from Vietnam makes us confident that our measure...

  14. FEATURES OF MEASURING IN LIQUID MEDIA BY ATOMIC FORCE MICROSCOPY

    Directory of Open Access Journals (Sweden)

    Mikhail V. Zhukov

    2016-11-01

    Full Text Available Subject of Research.The paper presents results of experimental study of measurement features in liquids by atomic force microscope to identify the best modes and buffered media as well as to find possible image artifacts and ways of their elimination. Method. The atomic force microscope Ntegra Aura (NT-MDT, Russia with standard prism probe holder and liquid cell was used to carry out measurements in liquids. The calibration lattice TGQ1 (NT-MDT, Russia was chosen as investigated structure with a fixed shape and height. Main Results. The research of probe functioning in specific pH liquids (distilled water, PBS - sodium phosphate buffer, Na2HPO4 - borate buffer, NaOH 0.1 M, NaOH 0.5 M was carried out in contact and semi-contact modes. The optimal operating conditions and the best media for the liquid measurements were found. Comparison of atomic force microscopy data with the results of lattice study by scanning electron microscopy was performed. The features of the feedback system response in the «probe-surface» interaction were considered by the approach/retraction curves in the different environments. An artifact of image inversion was analyzed and recommendation for its elimination was provided. Practical Relevance. These studies reveal the possibility of fine alignment of research method for objects of organic and inorganic nature by atomic force microscopy in liquid media.

  15. Microfluidic tactile sensors for three-dimensional contact force measurements.

    Science.gov (United States)

    Nie, Baoqing; Li, Ruya; Brandt, James D; Pan, Tingrui

    2014-11-21

    A microfluidic tactile sensing device has been first reported for three-dimensional contact force measurement utilizing the microfluidic interfacial capacitive sensing (MICS) principle. Consisting of common and differential microfluidic sensing elements and topologically micro-textured surfaces, the microfluidic sensing devices are intended not only to resolve normal mechanical loads but also to measure forces tangent to the surface upon contact. In response to normal or shear loads, the membrane surface deforms the underlying sensing elements uniformly or differentially. The corresponding variation in interfacial capacitance can be detected from each sensing unit, from which the direction and magnitude of the original load can be determined. Benefiting from the highly sensitive and adaptive MICS principle, the microfluidic sensor is capable of detecting normal forces with a device sensitivity of 29.8 nF N(-1) in a 7 mm × 7 mm × 0.52 mm package, which is at least a thousand times higher than its solid-state counterparts to our best knowledge. In addition, the microfluidic sensing elements enable facilitated relaxation response/time in the millisecond range (up to 12 ms). To demonstrate the utility and flexibility of the three-dimensional microfluidic sensor, it has been successfully configured into a fingertip-amounted setting for continuous tracing of the fingertip movement and contact force measurement.

  16. Optical tweezers force measurements to study parasites chemotaxis

    Science.gov (United States)

    de Thomaz, A. A.; Pozzo, L. Y.; Fontes, A.; Almeida, D. B.; Stahl, C. V.; Santos-Mallet, J. R.; Gomes, S. A. O.; Feder, D.; Ayres, D. C.; Giorgio, S.; Cesar, C. L.

    2009-07-01

    In this work, we propose a methodology to study microorganisms chemotaxis in real time using an Optical Tweezers system. Optical Tweezers allowed real time measurements of the force vectors, strength and direction, of living parasites under chemical or other kinds of gradients. This seems to be the ideal tool to perform observations of taxis response of cells and microorganisms with high sensitivity to capture instantaneous responses to a given stimulus. Forces involved in the movement of unicellular parasites are very small, in the femto-pico-Newton range, about the same order of magnitude of the forces generated in an Optical Tweezers. We applied this methodology to investigate the Leishmania amazonensis (L. amazonensis) and Trypanossoma cruzi (T. cruzi) under distinct situations.

  17. Evaluación electromiográfica de los músculos masticadores durante la fuerza máxima de mordedura Electromyography evaluations of the masticator muscles during the maximum bite force

    Directory of Open Access Journals (Sweden)

    M.J.P. Coelho-Ferraz

    2008-12-01

    Full Text Available La actividad de los músculos masetero y de la porción anterior temporal de ambos lados, derecho e izquierdo, respectivamente, durante la fuerza máxima de mordedura fue estudiada en voluntarios sanos. El estudio incluyó a 17 voluntarios adultos de ambos sexos, edad promedia de 25 años, que no evidenciaban ningún indicio de disfunción temporomandibular y eran relacionados con la Facultad de Odontología de Piracicaba. Se registraron los datos electromiográficos en ambos lados de la cara del masetero y de la porción anterior de los músculos temporal y suprahioideo en las posiciones postural e isométrica. Se utilizaron electrodos de superficie pasivos para niños, de Ag/AgCl, con forma circular y descargables de Meditrace® Kendall-LTP, modelo Chicopee MA01. Éstos se conectaron a un preamplificador con una ganancia de 20x que formaba un circuito de diferenciales. Se captaron los registros de las señales eléctricas utilizando un equipo EMG-8OOC de EMG System of Brazil, Ltd., de ocho canales, a una frecuencia de 2 KHz con 16 bitios de resolución y un filtro digital con un paso de banda de 20 a 500 Hz. Se utilizó también un transductor de presión que consistía en un tubo de goma con un sensor de presión (MPX 5700* (Motorola SPS, Austin, TX, EE.UU. para registrar la fuerza máxima de mordedura. El análisis estadístico incluyó la correlación lineal, la prueba t emparejada y el análisis de la varianza. Se consideró estadísticamente significativa una probabilidad de pHealthy individuals were examined in terms of the pattern of activity of the masseter and temporal muscles in their anterior portion of both right and left sides, respectively, with the maximum bite force. The study consisted in seventeen adult volunteers with no sign of apparent temporomandibular dysfunction, of both genders, connected to the School of Dentistry of Piracicaba, with average age of 25 years old. The electromyography data were obtained, bilaterally, of

  18. Breast Cancer EDGE Task Force Outcomes: Clinical Measures of Pain

    Science.gov (United States)

    Harrington, Shana; Gilchrist, Laura; Sander, Antoinette

    2014-01-01

    Background Pain is one of the most commonly reported impairments after breast cancer treatment affecting anywhere from 16-73% of breast cancer survivors Despite the high reported incidence of pain from cancer and its treatments, the ability to evaluate cancer pain continues to be difficult due to the complexity of the disease and the subjective experience of pain. The Oncology Section Breast Cancer EDGE Task Force was created to evaluate the evidence behind clinical outcome measures of pain in women diagnosed with breast cancer. Methods The authors systematically reviewed the literature for pain outcome measures published in the research involving women diagnosed with breast cancer. The goal was to examine the reported psychometric properties that are reported in the literature in order to determine clinical utility. Results Visual Analog Scale, Numeric Rating Scale, Pressure Pain Threshold, McGill Pain Questionnaire, McGill Pain Questionnaire – Short Form, Brief Pain Inventory and Brief Pain Inventory – Short Form were highly recommended by the Task Force. The Task Force was unable to recommend two measures for use in the breast cancer population at the present time. Conclusions A variety of outcome measures were used to measure pain in women diagnosed with breast cancer. When assessing pain in women with breast cancer, researchers and clinicians need to determine whether a unidimensional or multidimensional tool is most appropriate as well as whether the tool has strong psychometric properties. PMID:25346950

  19. Development of a shear force measurement dummy for seat comfort.

    Directory of Open Access Journals (Sweden)

    Seong Guk Kim

    Full Text Available Seat comfort is one of the main factors that consumers consider when purchasing a car. In this study, we develop a dummy with a shear-force sensor to evaluate seat comfort. The sensor has dimensions of 25 mm × 25 mm × 26 mm and is made of S45C. Electroless nickel plating is employed to coat its surface in order to prevent corrosion and oxidation. The proposed sensor is validated using a qualified load cell and shows high accuracy and precision (measurement range: -30-30 N; sensitivity: 0.1 N; linear relationship: R = 0.999; transverse sensitivity: <1%. The dummy is manufactured in compliance with the SAE standards (SAE J826 and incorporates shear sensors into its design. We measure the shear force under four driving conditions and at five different speeds using a sedan; results showed that the shear force increases with speed under all driving conditions. In the case of acceleration and deceleration, shear force significantly changes in the lower body of the dummy. During right and left turns, it significantly changes in the upper body of the dummy.

  20. Development of a shear force measurement dummy for seat comfort.

    Science.gov (United States)

    Kim, Seong Guk; Ko, Chang-Yong; Kim, Dong Hyun; Song, Ye Eun; Kang, Tae Uk; Ahn, Sungwoo; Lim, Dohyung; Kim, Han Sung

    2017-01-01

    Seat comfort is one of the main factors that consumers consider when purchasing a car. In this study, we develop a dummy with a shear-force sensor to evaluate seat comfort. The sensor has dimensions of 25 mm × 25 mm × 26 mm and is made of S45C. Electroless nickel plating is employed to coat its surface in order to prevent corrosion and oxidation. The proposed sensor is validated using a qualified load cell and shows high accuracy and precision (measurement range: -30-30 N; sensitivity: 0.1 N; linear relationship: R = 0.999; transverse sensitivity: <1%). The dummy is manufactured in compliance with the SAE standards (SAE J826) and incorporates shear sensors into its design. We measure the shear force under four driving conditions and at five different speeds using a sedan; results showed that the shear force increases with speed under all driving conditions. In the case of acceleration and deceleration, shear force significantly changes in the lower body of the dummy. During right and left turns, it significantly changes in the upper body of the dummy.

  1. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... biting your nails Nail biting typically begins in childhood and can continue through adulthood, and the side ... re inclined to bite may help solve the problem. Try to gradually stop biting your nails: Some ...

  2. Simulation of a flow around biting teeth

    Science.gov (United States)

    Narusawa, Hideaki; Yamamoto, Eriko; Kuwahara, Kunio

    2008-11-01

    We simulated a flow around biting teeth. The decayed tooth is a disease that a majority of people are annoyed. These are often generated from a deep groove at occlusal surface. It is known that a person who bites well doesn't suffer from a decayed tooth easily. Biting forces reach as much as 60 kg/cm^2 by an adult male, and when chewing, upper and lower teeth approach to bite by those forces. The crushed food mixed with saliva becomes high viscosity fluid, and is pushed out of ditches of teeth in the direction of the cheek or the tongue. Teeth with complex three dimension curved surface are thought to form venturi at this time, and to generate big pressure partially. An excellent dental articulation will possibly help a natural generation of a flow to remove dental plaque, i.e. the cause of the decayed tooth. Moreover, the relation of this flow with the destruction of the filled metal or the polymer is doubted. In this research, we try to clarify the pressure distributions by this flow generation as well as its dynamics when chewing. One of our goals is to enable an objective design of the shape of the dental fillings and the artificial tooth. Tooth has a very small uneven ground and a bluff body. In this case, to calculate a computational numerical simulation to solve the Navier-Stokes equations three dimension Cartesian coordinate system is employed.

  3. Novel parallel plate condenser for single particle electrostatic force measurements in atomic force microscope

    KAUST Repository

    Kwek, Jin Wang

    2011-07-01

    A combination of small parallel plate condenser with Indium Tin Oxide (ITO) glass slides as electrodes and an atomic force microscope (AFM) is used to characterize the electrostatic behavior of single glass bead microparticles (105-150 μm) glued to the AFM cantilever. This novel setup allows measurements of the electrostatic forces acting on a particle in an applied electrical field to be performed in ambient air conditions. By varying the position of the microparticle between the electrodes and the strength of the applied electric field, the relative contributions of the particle net charge, induced and image charges were investigated. When the microparticle is positioned in the middle of the electrodes, the force acting on the microparticle was linear with the applied electric field and proportional to the microparticle net charge. At distances close to the bottom electrode, the force follows a parabolic relationship with the applied electric field reflecting the contributions of induced and image charges. The method can be used for the rapid evaluation of the charging and polarizability properties of the microparticle as well as an alternative to the conventional Faraday\\'s pail technique. © 2011 Elsevier B.V.

  4. What Effect Did General Order Number 1 and the Force Protection Measures Have on Task Force Eagle Operations in Bosnia During Implementation Force?

    National Research Council Canada - National Science Library

    Yates, William

    2002-01-01

    This thesis is a historical study to determine the effect General Order Number 1 and the Force Protection Measures had on Task Force Eagle operations during the deployment of the NATO Implementation...

  5. Força de mordida em crianças com mantenedor de espaço funcional na fase da dentadura mista inicial Bite force in children with functional space maintainer in early mixed dentition

    Directory of Open Access Journals (Sweden)

    Suzane Rodrigues Jacinto-Gonçalves

    2009-08-01

    Full Text Available OBJETIVO: verificar a influência do mantenedor de espaço funcional (MEF na força muscular em crianças com perda prematura de molares decíduos na fase inicial da dentadura mista (5,5 a 6,5 anos de idade com oclusão normal, considerando-se o padrão facial. MÉTODOS: a amostra foi constituída por dois grupos: Grupo MEF (n = 15, com perda precoce de pelo menos um molar decíduo; e Grupo Controle (n = 16. Determinou-se a força de mordida máxima (FM com um tubo transmissor pressurizado, conectado a um circuito eletrônico analógico/digital antes (t0, um mês (t1 e 6 meses (t6 após a instalação do mantenedor. O padrão facial foi determinado pelo índice de Jarabak (FHR. Os dados foram analisados pela estatística descritiva, análise de variância para medidas repetidas, teste t e correlação de Pearson. RESULTADOS:a FM foi significativamente menor em t0 e t1 para o Grupo MEF em relação ao Controle. Em t6 não houve diferença. Os dois grupos apresentaram a FM significativamente maior em t6, em relação a t0, mas o percentual de variação para o Grupo MEF foi significativamente maior. Os valores de FHR não se correlacionaram com a FM, não ocorrendo diferença entre os tipos faciais intragrupos. Os dolicofaciais do Grupo MEF apresentaram a FM significativamente menor que os do Grupo Controle, em t0 e t1, mas não em t6. CONCLUSÃO: o maior aumento na FM para o Grupo MEF após 6 meses foi favorecido pelo maior número de contatos oclusais, devido aos dentes artificiais, melhorando a função e recuperando a força muscular.AIM: To verify the influence of a functional space maintainer (FSM in muscle strength in children with premature loss of primary molars in early mixed dentition (5.5-6.5 years old with normal occlusion, considering the facial pattern. METHODS: The sample was distributed in: FSM Group (n = 15, with premature loss of at least one primary molar and a Control Group (n = 16. It was determined the maximal bite force (BF

  6. Diameter measurements of polystyrene particles with atomic force microscopy

    Science.gov (United States)

    Garnaes, J.

    2011-09-01

    The size of (nano) particles is a key parameter used in controlling their function. The particle size is also important in order to understand their physical and chemical properties and regulate their number in health and safety issues. In this work, the geometric diameters of polystyrene spheres of nominal diameter 100 nm are measured using atomic force microscopy. The measurements are based on the apex height and on the average distance between neighbouring spheres when they form a close-packed monolayer on a flat mica substrate. The most important influence parameters for the determination of the geometric diameter are the lateral air gaps and deformation of the spheres. The lateral air gaps are caused by significant size variations of the individual spheres, and a correction is calculated based on the simulation of packing of spheres. The deformation of the spheres is caused mainly by capillary forces acting when they are in contact with each other or with the mica substrate. Based on calculated capillary forces and the literature values of the elastic properties of the polystyrene and mica, the deformation is estimated to be 2 nm with a standard uncertainty of 2 nm. The geometric diameter of the polystyrene spheres was measured with a combined standard uncertainty of ≈3 nm. The measured vertical diameter of 92.3 nm and the certified mobility equivalent diameter measured by differential mobility analysis (DMA) are marginally consistent at a confidence level of 95%. However, the measured lateral geometric diameter was 98.9 nm and is in good agreement with DMA.

  7. Funnel-web spider bite

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/002844.htm Funnel-web spider bite To use the sharing features on ... the effects of a bite from the funnel-web spider. Male funnel-web spiders are more poisonous ...

  8. Marine animal stings or bites

    Science.gov (United States)

    Stings - marine animals; Bites - marine animals ... Things you can do to prevent a marine animal sting or bite include: Swim near a lifeguard. Observe posted signs that may warn of danger from jellyfish or other hazardous marine life. ...

  9. Insect bite hypersensitivity in horses: genetic and epidemiological analysis

    NARCIS (Netherlands)

    Schurink, A.

    2012-01-01

    Insect bite hypersensitivity (IBH) is the most common allergic skin disease in horses and is caused by bites of Culicoides spp. IBH reduces welfare of affected horses and at present no effective preventive measure or cure exists. Aim of our research was to increase knowledge of the

  10. Measuring the greenhouse effect and radiative forcing through the atmosphere

    Science.gov (United States)

    Philipona, Rolf; Kräuchi, Andreas; Brocard, Emmanuel

    2013-04-01

    In spite of a large body of existing measurements of incoming shortwave solar radiation and outgoing longwave terrestrial radiation at the Earth's surface and at the top of the atmosphere, there are few observations documenting how radiation profiles change through the atmosphere - information that is necessary to fully quantify the greenhouse effect of the Earth's atmosphere. Using weather balloons and specific radiometer equipped radiosondes, we continuously measured shortwave and longwave radiation fluxes from the surface of the Earth up to altitudes of 35 kilometers in the upper stratosphere. Comparing radiation profiles from night measurements with different amounts of water vapor, we show evidence of large greenhouse forcing. We show, that under cloud free conditions, water vapor increases with Clausius-Clapeyron ( 7% / K), and longwave downward radiation at the surface increases by 8 Watts per square meter per Kelvin. The longwave net radiation however, shows a positive increase (downward) of 2.4 Watts per square meter and Kelvin at the surface, which decreases with height and shows a similar but negative increase (upward) at the tropopause. Hence, increased tropospheric water vapor increases longwave net radiation towards the ground and towards space, and produces a heating of 0.42 Kelvin per Watt per square meter at the surface. References: Philipona et al., 2012: Solar and thermal radiation profiles and radiative forcing measured through the atmosphere. Geophys. Res. Lett., 39, L13806, doi: 10.1029/2012GL052087.

  11. Animal Bites - Multiple Languages

    Science.gov (United States)

    ... Spanish (español) Vietnamese (Tiếng Việt) HealthReach resources will open in a new window. Arabic (العربية) Expand Section Animal Bites and Scratches - العربية (Arabic) Bilingual PDF Health Information ...

  12. Mosquito Bites are Bad!

    Centers for Disease Control (CDC) Podcasts

    2016-08-11

    In this podcast for kids, the Kidtastics talk about the dangers of mosquito bites and how to prevent getting them.  Created: 8/11/2016 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/11/2016.

  13. Prevent Bite Wounds

    Science.gov (United States)

    ... most bites come from domesticated animals that the child knows, not from wild or unfamiliar animals. A major concern for parents ... some tips to keep in mind. Teach your child to avoid contact with wild animals. She also needs to stay away from ...

  14. Spider Bites: First Aid

    Science.gov (United States)

    ... t had one in the last five years. Black widow spider You can usually identify a black widow spider by the hourglass marking on its belly. In ... in the South. Signs and symptoms of a black widow spider bite may include: At first, slight swelling and ...

  15. Bug Bites and Stings

    Science.gov (United States)

    ... or sting. Handling Bee and Wasp Stings A bee will usually leave behind a stinger attached to a venom sac. Try to remove it as quickly as ... child has had an allergic reaction to a bee or wasp sting in the past, see your ... shape on its underbelly. The venom (a toxic substance) in a black widow bite ...

  16. African tick bite fever

    DEFF Research Database (Denmark)

    Johansen, Jakob Aaquist; Thybo, Søren

    2011-01-01

    The incident of spotted fever imported to Denmark is unknown. We present a classic case of African Tick Bite Fever (ATBF) to highlight a disease, which frequently infects wildlife enthusiasts and hunters on vacation in South Africa. ATBF has a good prognosis and is easily treated with doxycyclin...

  17. Biting into Big Numbers.

    Science.gov (United States)

    Anderson, Maureen McCahan

    1996-01-01

    A mnemonic clue sentence--"He thinks mice bite trees"--is suggested for helping students with learning disabilities or mild mental retardation successfully identify up to 15 digit numbers by relating the sentence to the sequence of hundreds, thousands, millions, billions, and trillions. (DB)

  18. Rat bite fever.

    NARCIS (Netherlands)

    Gaastra, W.; Boot, R.G.A.; Ho, H.; Lipman, L.J.A.

    2009-01-01

    Rat bite fever (RBF) is a bacterial zoonosis for which two causal bacterial species have been identified: Streptobacillis moniliformis and Spirillum minus. Haverhill fever (HF) is a form of S. moniliformis infection believed to develop after ingestion of contaminated food or water. Here the

  19. Preparation of stable silica surfaces for surface forces measurement

    Science.gov (United States)

    Ren, Huai-Yin; Mizukami, Masashi; Kurihara, Kazue

    2017-09-01

    A surface forces apparatus (SFA) measures the forces between two surfaces as a function of the surface separation distance. It is regarded as an essential tool for studying the interactions between two surfaces. However, sample surfaces used for the conventional SFA measurements have been mostly limited to thin (ca. 2-3 μm) micas, which are coated with silver layers (ca. 50 nm) on their back, due to the requirement of the distance determination by transmission mode optical interferometry called FECO (fringes of equal chromatic order). The FECO method has the advantage of determining the absolute distance, so it should be important to increase the availability of samples other than mica, which is chemically nonreactive and also requires significant efforts for cleaving. Recently, silica sheets have been occasionally used in place of mica, which increases the possibility of surface modification. However, in this case, the silver layer side of the sheet is glued on a cylindrical quartz disc using epoxy resin, which is not stable in organic solvents and can be easily swollen or dissolved. The preparation of substrates more stable under severe conditions, such as in organic solvents, is necessary for extending application of the measurement. In this study, we report an easy method for preparing stable silica layers of ca. 2 μm in thickness deposited on gold layers (41 nm)/silica discs by sputtering, then annealed to enhance the stability. The obtained silica layers were stable and showed no swelling in organic solvents such as ethanol and toluene.

  20. Measurements of electrostatic double layer potentials with atomic force microscopy

    Science.gov (United States)

    Giamberardino, Jason

    The aim of this thesis is to provide a thorough description of the development of theory and experiment pertaining to the electrostatic double layer (EDL) in aqueous electrolytic systems. The EDL is an important physical element of many systems and its behavior has been of interest to scientists for many decades. Because many areas of science and engineering move to test, build, and understand systems at smaller and smaller scales, this work focuses on nanoscopic experimental investigations of the EDL. In that vein, atomic force microscopy (AFM) will be introduced and discussed as a tool for making high spatial resolution measurements of the solid-liquid interface, culminating in a description of the development of a method for completely characterizing the EDL. This thesis first explores, in a semi-historical fashion, the development of the various models and theories that are used to describe the electrostatic double layer. Later, various experimental techniques and ideas are addressed as ways to make measurements of interesting characteristics of the EDL. Finally, a newly developed approach to measuring the EDL system with AFM is introduced. This approach relies on both implementation of existing theoretical models with slight modifications as well as a unique experimental measurement scheme. The model proposed clears up previous ambiguities in definitions of various parameters pertaining to measurements of the EDL and also can be used to fully characterize the system in a way not yet demonstrated.

  1. Force measuring optical tweezers system for long time measurements of P pili stability

    Science.gov (United States)

    Andersson, Magnus; Fällman, Erik; Uhlin, Bernt Eric; Axner, Ove

    2006-02-01

    A force-measuring optical tweezers instrumentation and long time measurements of the elongation and retraction of bacterial fimbriae from Uropathogenic E. coli (UPEC) under strain are presented. The instrumentation is presented in some detail. Special emphasis is given to measures taken to reduce the influence of noise and drifts in the system and from the surrounding, which makes long term force measurements possible. Individual P pili from UPEC bacteria were used as a biological model system for repetitive unfolding and refolding cycles of bacterial fimbriae under equilibrium conditions. P pili have evolved into a three-dimensional helix-like structure, the PapA rod, that can be successively and significantly elongated and/or unfolded when exposed to external forces. The instrumentation is used for characterization of the force-vs.-elongation response of the PapA rod of individual P pili, with emphasis on the long time stability of the forced unfolding and refolding of the helical structure of the PapA rod. The results show that the PapA rod is capable of withstanding extensive strain, leading to a complete unfolding of the helical structure, repetitive times during the life cycle of a bacterium without any noticeable alteration of the mechanical properties of the P pili. This function is believed to be importance for UPEC bacteria in vivo since it provides a close contact to a host cell (which is an initial step of invasion) despite urine cleaning attempts.

  2. Multilayer Steel Materials Deformation Resistance and Roll Force Measurement

    Directory of Open Access Journals (Sweden)

    A. G. Kolesnikov

    2014-01-01

    Full Text Available To create new types of cars, raise their reliability, gain operational life, and decrease in metal consumption of products it is necessary to improve mechanical, physical, and also special properties of the constructional materials applied in mechanical engineering. Presently, there are intensive researches and developments under way to create materials with ultrafine-grained structure (the sizes of grains in their crystal lattice make less than 1 micron in one of the measurements.BMSTU developed a manufacturing technology of multilayer steel sheets with steady ultrafine-grained structure based on the multiple hot rolling of billet as a composition consisting of the alternating metal sheets. A principled condition for implementation of such technology is existence of different crystallographic modifications in the adjoining sheets of the composition at specified temperature of rolling.Power parameters of rolling are important technical characteristics of the process. Usually, to determine a deformation resistance value when rolling the diverse multilayer materials, is used the actual resistance value averaging in relation to the components of the composition. The aim of this work is a comparative analysis of known calculated dependences with experimental data when rolling the 100-layer samples. Objects of research were the 100-layer compositions based on the alternating layers of steel 08H18N10 and U8.Experimental samples represented the vacuumized capsules with height, width, and length of 53 mm x 53 mm x 200 mm, respectively, in which there were the 100-layer packs from sheets, each of 0.5 mm, based on the composition of steels (U8+08H18N10. Rolling was made on the double-high mill with rolls of 160 mm in diameter during 19 passes to the thickness of 7 mm with the speed of 0,1 m/s. Relative sinking in each pass was accepted to be equal 10±2,5%. Rolling forces were measured by the strain-gauging method using the measuring cells, located under

  3. Bites of Lists - mapping and filtering sublists

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    The idea of applying map and filter functions on consecutive sublists instead of on individual list elements is discussed and developed in this paper. A non-empty, consecutive sublist is called a bite. Both map and filter functions accept a function parameter - a bite function - which...... is responsible for returning a prefix bite of a list. We develop families of bite functions via a collection of higher-order bite generators. On top of the bite generators, a number of bite mapping and bite filtering functions are introduced. We illustrate the usefulness of bite mapping and filtering via...

  4. Prototype to measure bracket debonding force in vivo

    Directory of Open Access Journals (Sweden)

    Jéssika Lagni Tonus

    Full Text Available ABSTRACT Introduction: Material biodegradation that occurs in the mouth may interfere in the bonding strength between the bracket and the enamel, causing lower bond strength values in vivo, in comparison with in vitro studies. Objective: To develop a prototype to measure bracket debonding force in vivo and to evaluate, in vitro, the bond strength obtained with the prototype. Methods: A original plier (3M Unitek was modified by adding one strain gauge directly connected to its claw. An electronic circuit performed the reading of the strain gauge, and the software installed in a computer recorded the values of the bracket debonding force, in kgf. Orthodontic brackets were bonded to the facial surface of 30 bovine incisors with adhesive materials. In Group 1 (n = 15, debonding was carried out with the prototype, while tensile bond strength testing was performed in Group 2 (n = 15. A universal testing machine was used for the second group. The adhesive remnant index (ARI was recorded. Results: According to Student’s t test (α = 0.05, Group 1 (2.96 MPa and Group 2 (3.08 MPa were not significantly different. ARI score of 3 was predominant in the two groups. Conclusion: The prototype proved to be reliable for obtaining in vivo bond strength values for orthodontic brackets.

  5. Cervical vertebral column morphology and head posture in preorthodontic patients with anterior open bite.

    Science.gov (United States)

    Kim, Phong; Sarauw, Martin Toft; Sonnesen, Liselotte

    2014-03-01

    Cervical vertebral column morphology and head posture were examined and related to craniofacial morphology in preorthodontic children and adolescents with anterior open bite. One hundred eleven patients (ages, 6-18 years) with an anterior open bite of more than 0 mm were divided into 2 groups of skeletal or dentoalveolar open bite. The skeletal open-bite group comprised 38 subjects (19 girls, 19 boys). The dentoalveolar open-bite group comprised 73 subjects (43 girls, 30 boys). Visual assessment of the cervical column and measurements of craniofacial morphology and head posture were made on profile radiographs. Deviations in the cervical vertebral column morphology occurred in 23.7% of the subjects in the skeletal open-bite group and in 19.2% in the dentoalveolar open-bite group, but the difference was not significant. Head posture was significantly more extended in the skeletal open-bite group compared with the dentoalveolar open-bite group (craniovertical angle [Mx/VER], P open bite. No significant differences in the cervical vertebral column's morphologic deviations were found between the skeletal and the dentoalveolar open-bite groups. Significant differences were found in head posture between the groups and with regard to associations with craniofacial dimensions. This might indicate a respiratory etiologic component in children with anterior open bite. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  6. The validity of plantarflexor strength measures obtained through hand-held dynamometry measurements of force.

    Science.gov (United States)

    Marmon, Adam R; Pozzi, Federico; Alnahdi, Ali H; Zeni, Joseph A

    2013-12-01

    Hand-held dynamometers are commonly used to assess plantarflexor strength during rehabilitation. The purpose of this study was to determine the concurrent validity of measuring plantarflexion force using a hand-held dynamometer (HHD) as compared to an electromechanical dynamometer as the gold standard. The hypothesis was that plantarflexor forces obtained using a hand-held dynamometer would not show absolute agreement with a criterion standard. Concurrent validity assessment for a diagnostic strength testing device. Institutional clinic and research laboratory. Volunteer sample of healthy university students (N=20, 10 women, 10 men; 25.9±4.1 years). Maximal plantarflexion strength was measured using both a HHD and an electromechanical dynamometer (EMD) as a criterion measure. Plantarflexor force measures with the HHD were significantly different (p<0.01) and not correlated with plantarflexor forces measured using the EMD for either limb (R(2) ≤ 0.09). Plantarflexor strength measurements acquired using HHD are different from those acquired using an EMD and are likely influenced by the strength of the examiner. Prospective cohort study, level II.

  7. Force

    CERN Document Server

    Graybill, George

    2007-01-01

    Forces are at work all around us. Discover what a force is, and different kinds of forces that work on contact and at a distance. We use simple language and vocabulary to make this invisible world easy for students to ""see"" and understand. Examine how forces ""add up"" to create the total force on an object, and reinforce concepts and extend learning with sample problems.

  8. Sensor Prototype to Evaluate the Contact Force in Measuring with Coordinate Measuring Arms

    Directory of Open Access Journals (Sweden)

    Eduardo Cuesta

    2015-06-01

    Full Text Available This paper describes the design, development and evaluation tests of an integrated force sensor prototype for portable Coordinate Measuring Arms (CMAs or AACMMs. The development is based on the use of strain gauges located on the surface of the CMAs’ hard probe. The strain gauges as well as their cables and connectors have been protected with a custom case, made by Additive Manufacturing techniques (Polyjet 3D. The same method has been selected to manufacture an ergonomic handle that includes trigger mechanics and the electronic components required for synchronizing the trigger signal when probing occurs. The paper also describes the monitoring software that reads the signals in real time, the calibration procedure of the prototype and the validation tests oriented towards increasing knowledge of the forces employed in manual probing. Several experiments read and record the force in real time comparing different ways of probing (discontinuous and continuous contact and measuring different types of geometric features, from single planes to exterior cylinders, cones, or spheres, through interior features. The probing force is separated into two components allowing the influence of these strategies in probe deformation to be known. The final goal of this research is to improve the probing technique, for example by using an operator training programme, allowing extra-force peaks and bad contacts to be minimized or just to avoid bad measurements.

  9. Measurement of Forces and Moments Transmitted to the Residual Limb

    Science.gov (United States)

    2010-10-01

    the floor, but only changes the length of the heel and toe lever arms. Additional evidence statements and the associated levels of confidence...Interface Biomechanical Correlate Force X Anterior-Posterior Force Perpendicular to Pylon Anterior-Posterior Force on Limb Braking and Propulsion...heel lever arm. The other significant changes were all less than 10% of the absolute values of the forces and moments. Significant differences in

  10. Food aroma affects bite size

    Directory of Open Access Journals (Sweden)

    de Wijk René A

    2012-03-01

    Full Text Available Abstract Background To evaluate the effect of food aroma on bite size, a semisolid vanilla custard dessert was delivered repeatedly into the mouth of test subjects using a pump while various concentrations of cream aroma were presented retronasally to the nose. Termination of the pump, which determined bite size, was controlled by the subject via a push button. Over 30 trials with 10 subjects, the custard was presented randomly either without an aroma, or with aromas presented below or near the detection threshold. Results Results for ten subjects (four females and six males, aged between 26 and 50 years, indicated that aroma intensity affected the size of the corresponding bite as well as that of subsequent bites. Higher aroma intensities resulted in significantly smaller sizes. Conclusions These results suggest that bite size control during eating is a highly dynamic process affected by the sensations experienced during the current and previous bites.

  11. Forces due to surface water measured by force microscopy. Consequences for anchoring biological cells to surfaces

    International Nuclear Information System (INIS)

    Schilcher, K.

    1997-05-01

    Interaction forces in 'Scanning Force Microscopy' (SFM). Force curves revealed exponentially decaying, attractive forces between silicon tip and silicon sample in aqueous media. Replacing the silicon sample by a sheet of mica, the interaction forces had both, an attractive and a repulsive component. Addition of salts generally reduced the forces. At 500 mM salt concentration, the attractive force became quantized with a residual force value of 23 pN. The attractive force is attributed to the gain in energy of water molecules which are released from surface water into free water during tip-sample approach. This conclusion is supported by a statistical model. The repulsive force contribution in the case of mica, is caused by hydration forces due to the spatial organization of crystalline water on the mica surface. Anchoring of biological cells. Molecular resolution of cell surfaces by SFM requires cell anchoring without interference with cell physiology. For this a novel strategy, 'hydrophobic anchoring' was designed. It avoids strong attractive forces between cell and by using a flexible spacer molecule. It establishes anchoring by a lipid (bound to the spacer), which weakly interacts with the hydrophobic core of the cell membrane. The method was subjected to tests using RBL-2H3, CH0 αβ and HEK-293 cells. The strength of cell anchoring was assayed by shear forces. In all cases 'hydrophobic anchoring' via a spacer caused elective anchoring much beyond controls. Such cell anchoring was employed for the imaging of RBL-2H3 cells by SFM. Images showed considerable finer details than images of loosely adsorbed cells. With about 50 rim resolution, SFM succeeded in imaging microvilli, filopodia, single cytoskeletal fibers (microtubules, microfilaments) and vesicles. In addition, as a consequence of cell stimulation upon ionomycin treatment, lamellae formation and the appearance of secretory granules on top of them were observed which indicates the viability of anchored

  12. An inductive sensor for real-time measurement of plantar normal and shear forces distribution.

    Science.gov (United States)

    Du, Li; Zhu, Xiaoliang; Zhe, Jiang

    2015-05-01

    The objective of this paper is to demonstrate a multiplexed inductive force sensor for simultaneously measuring normal force and shear forces on a foot. The sensor measures the normal force and shear forces by monitoring the inductance changes of three planar sensing coils. Resonance frequency division multiplexing was applied to signals from the multiple sensing coils, making it feasible to simultaneously measure the three forces (normal force, shear forces in x- and y-axis) on a foot using only one set of measurement electronics with high sensitivity and resolution. The testing results of the prototype sensor have shown that the sensor is capable of measuring normal force ranging from 0 to 800 N and shear forces ranging from 0 to 130 N in real time. With its high resolution, high sensitivity, and the capability of monitoring forces at different positions of a foot simultaneously, this sensor can be potentially used for real-time measurement of plantar normal force and shear forces distribution on diabetes patient's foot. Real-time monitoring of the normal force and shear forces on diabetes patient's foot can provide useful information for physicians and diabetes patients to take actions in preventing foot ulceration.

  13. Bug bites and stings: When to see a dermatologist

    Medline Plus

    Full Text Available ... laws Quality DataDerm Quality measures Clinical guidelines Appropriate use criteria Choosing Wisely Education Online Learning Center MOC ... prevent bug bites, dermatologists recommend the following tips: Use insect repellent. To protect against mosquitoes, ticks and ...

  14. Aerosol Direct Radiative Forcing and Forcing Efficiencies at Surface from the shortwave Irradiance Measurements in Abu Dhabi, UAE

    Science.gov (United States)

    Beegum S, N.; Ben Romdhane, H.; Ghedira, H.

    2013-12-01

    Atmospheric aerosols are known to affect the radiation balance of the Earth-Atmospheric system directly by scattering and absorbing the solar and terrestrial radiation, and indirectly by affecting the lifetime and albedo of the clouds. Continuous and simultaneous measurements of short wave global irradiance in combination with synchronous spectral aerosol optical depth (AOD) measurements (from 340 nm to 1640 nm in 8 channels), for a period of 1 year from June 2012 to May 2013, were used for the determination of the surface direct aerosol radiative forcing and forcing efficiencies under cloud free conditions in Abu Dhabi (24.42°N, 54.61o E, 7m MSL), a coastal location in United Arab Emirates (UAE) in the Arabian Peninsula. The Rotating Shadow band Pyranometer (RSP, LI-COR) was used for the irradiance measurements (in the spectral region 400-1100 nm), whereas the AOD measurements were carried out using CIMEL Sunphotometer (CE 318-2, under AERONET program). The differential method, which is neither sensitive to calibration uncertainties nor model assumptions, has been employed for estimating forcing efficiencies from the changes in the measured fluxes. The forcing efficiency, which quantifies the net change in irradiance per unit change in AOD, is an appropriate parameter for the characterization of the aerosol radiative effects even if the microphysical and optical properties of the aerosols are not completely understood. The corresponding forcing values were estimated from the forcing efficiencies. The estimated radiative forcing and forcing efficiencies exhibited strong monthly variations. The forcing efficiencies (absolute magnitudes) were highest during March, and showed continuous decrease thereafter to reach the lowest value during September. In contrast, the forcing followed a slightly different pattern of variability, with the highest solar dimming during April ( -60 W m-2) and the minimum during February ( -20 W m-2). The results indicate that the aerosol

  15. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... skin, hair, and nails Skin dictionary Camp Discovery Good Skin Knowledge lesson plans and activities Video library ... biting. Replace the nail-biting habit with a good habit: When you feel like biting your nails, ...

  16. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... re inclined to bite may help solve the problem. Try to gradually stop biting your nails: Some doctors recommend taking a gradual approach to break the habit. Try to stop biting ...

  17. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... this safe, but awful-tasting formula discourages many people from biting their nails. Get regular manicures: Spending ... longer bite any of your nails. For some people, nail biting may be a sign of a ...

  18. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... public", "mcat1=de12", ]; for (var c = 0; c How to stop biting your nails Nail biting typically ... to bite your nails, you can figure out how to avoid these situations and develop a plan ...

  19. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... your fingers and from your nails to your face and mouth. To help you stop biting your ... re inclined to bite may help solve the problem. Try to gradually stop biting your nails: Some ...

  20. Measuring Resilience to Operational Stress in Canadian Armed Forces Personnel.

    Science.gov (United States)

    Hellewell, Sarah C; Cernak, Ibolja

    2018-02-01

    Adaptability to stress is governed by innate resilience, comprised of complex neuroendocrine and immune mechanisms alongside inherited or learned behavioral traits. Based on their capacity to adapt, some people thrive in stressful situations, whereas others experience maladaptation. In our study, we used state-of-the-art tools to assess the resilience level in individuals, as well as their susceptibility to developing military stress-induced behavioral and cognitive deficits. To address this complex question, we tested Canadian Armed Forces (CAF) personnel in three distinct stress environments (baselines): during predeployment training, deployment in Afghanistan, and readjustment upon return to Canada. Our comprehensive outcome measures included psychometric tests, saliva biomarkers, and computerized cognitive tests that used the Cambridge Neuropsychological Automated Test Battery. Participants were categorized based on initial biomarker measurements as being at low-, moderate-, or high stress-maladaptation risk. Biomarkers showed significant changes (ds = 0.56 to 2.44) between baselines, calculated as "delta" changes. Participants at low stress-maladaptation risk demonstrated minimal changes, whereas those at high stress-maladaptation risk showed significant biomarker variations. The psychometric patterns and cognitive functions were likewise affected across baselines, suggesting that the panel of saliva stress biomarkers could be a useful tool for determining the risk of stress maladaptation that can cause psychological and cognitive decline. Copyright © 2018 International Society for Traumatic Stress Studies.

  1. A relationship between three-dimensional surface hydration structures and force distribution measured by atomic force microscopy

    Science.gov (United States)

    Miyazawa, Keisuke; Kobayashi, Naritaka; Watkins, Matthew; Shluger, Alexander L.; Amano, Ken-Ichi; Fukuma, Takeshi

    2016-03-01

    Hydration plays important roles in various solid-liquid interfacial phenomena. Very recently, three-dimensional scanning force microscopy (3D-SFM) has been proposed as a tool to visualise solvated surfaces and their hydration structures with lateral and vertical (sub) molecular resolution. However, the relationship between the 3D force map obtained and the equilibrium water density, ρ(r), distribution above the surface remains an open question. Here, we investigate this relationship at an interface of an inorganic mineral, fluorite, and water. The force maps measured in pure water are directly compared to force maps generated using the solvent tip approximation (STA) model and from explicit molecular dynamics simulations. The results show that the simulated STA force map describes the major features of the experimentally obtained force image. The agreement between the STA data and the experiment establishes the correspondence between the water density used as an input to the STA model and the experimental hydration structure and thus provides a tool to bridge the experimental force data and atomistic solvation structures. Further applications of this method should improve the accuracy and reliability of both interpretation of 3D-SFM force maps and atomistic simulations in a wide range of solid-liquid interfacial phenomena.Hydration plays important roles in various solid-liquid interfacial phenomena. Very recently, three-dimensional scanning force microscopy (3D-SFM) has been proposed as a tool to visualise solvated surfaces and their hydration structures with lateral and vertical (sub) molecular resolution. However, the relationship between the 3D force map obtained and the equilibrium water density, ρ(r), distribution above the surface remains an open question. Here, we investigate this relationship at an interface of an inorganic mineral, fluorite, and water. The force maps measured in pure water are directly compared to force maps generated using the solvent

  2. Reality Bites: Biting at the Center--Part 1.

    Science.gov (United States)

    Greenman, Jim; Stonehouse, Anne Willis

    1994-01-01

    Examines the problem of biting in group child care, especially among toddlers. Discusses reasons for the behavior such as teething, impulsiveness and lack of self control, excitement and overstimulation, and frustration. Offers advice for child caregivers when biting occurs in their program. (TJQ)

  3. Dynamic and static measurement of interfacial capillary forces by a hybrid nanomechanical system.

    Science.gov (United States)

    Kwon, Soyoung; Stambaugh, Corey; Kim, Bongsu; An, Sangmin; Jhe, Wonho

    2014-05-21

    The forces resulting from the presence of interfacial liquids have mechanical importance under ambient conditions. For holistic understanding of the liquid-mediated interactions, we combine the force-gradient sensitivity of an atomic force microscope (AFM) with the force measuring capability of a micro-electromechanical force sensor. Simultaneous measurement of the viscoelasticity of the water nanomeniscus and the absolute capillary force shows excellent agreement in its entire length, which justifies the validity of the widely used AFM results. We apply the hybrid system to measure the stress and strain, whose hysteretic response provides the intrinsic quantities of the liquid nanocluster.

  4. Exploring Heat Stress Relief Measures among the Australian Labour Force.

    Science.gov (United States)

    Zander, Kerstin K; Mathew, Supriya; Garnett, Stephen T

    2018-02-26

    Australia experiences frequent heat waves and generally high average temperatures throughout the continent with substantial impacts on human health and the economy. People adapt to heat by adopting various relief measures in their daily lives including changing their behaviour. Many labour intensive outdoor industries implement standards for heat stress management for their workforce. However, little is known about how people cope with heat at their workplaces apart from studies targeting some specific industries where labourers are exposed to extreme heat. Here, we analysed responses from 1719 people in the Australian labour force to self-reported heat stress and associated coping mechanisms. Three quarters of respondents experienced heat stress at their workplace with fatigue and headache being the two most frequently stated symptoms. Almost all of those who were affected by heat would hydrate (88%), 67% would cool, and 44% would rest as a strategy for coping with heat. About 10% intended to change their jobs because of heat stress in the workplace. We found differences in heat relief measures across gender, education, health, level of physical intensity of job, and time spent working outside. People working in jobs that were not very demanding physically were more likely to choose cooling down as a relief measure, while those in labour intensive jobs and jobs that required considerable time outside were more likely to rest. This has potential consequences for their productivity and work schedules. Heat affects work in Australia in many types of industry with impact dependent on workforce acclimatisation, yet public awareness and work relief plans are often limited to outdoor and labour intensive industries. Industries and various levels of government in all sectors need to implement standards for heat management specific to climate zones to help people cope better with high temperatures as well as plan strategies in anticipation of projected temperature

  5. Exploring Heat Stress Relief Measures among the Australian Labour Force

    Directory of Open Access Journals (Sweden)

    Kerstin K. Zander

    2018-02-01

    Full Text Available Australia experiences frequent heat waves and generally high average temperatures throughout the continent with substantial impacts on human health and the economy. People adapt to heat by adopting various relief measures in their daily lives including changing their behaviour. Many labour intensive outdoor industries implement standards for heat stress management for their workforce. However, little is known about how people cope with heat at their workplaces apart from studies targeting some specific industries where labourers are exposed to extreme heat. Here, we analysed responses from 1719 people in the Australian labour force to self-reported heat stress and associated coping mechanisms. Three quarters of respondents experienced heat stress at their workplace with fatigue and headache being the two most frequently stated symptoms. Almost all of those who were affected by heat would hydrate (88%, 67% would cool, and 44% would rest as a strategy for coping with heat. About 10% intended to change their jobs because of heat stress in the workplace. We found differences in heat relief measures across gender, education, health, level of physical intensity of job, and time spent working outside. People working in jobs that were not very demanding physically were more likely to choose cooling down as a relief measure, while those in labour intensive jobs and jobs that required considerable time outside were more likely to rest. This has potential consequences for their productivity and work schedules. Heat affects work in Australia in many types of industry with impact dependent on workforce acclimatisation, yet public awareness and work relief plans are often limited to outdoor and labour intensive industries. Industries and various levels of government in all sectors need to implement standards for heat management specific to climate zones to help people cope better with high temperatures as well as plan strategies in anticipation of projected

  6. Morphology of open bite.

    Science.gov (United States)

    Krey, Karl-Friedrich; Dannhauer, Karl-Heinz; Hierl, Thomas

    2015-05-01

    The purpose of this work was to define and illustrate the skeletal morphology of open-bite patients against the background of sagittal jaw relationships on the basis of lateral cephalograms. Lateral cephalograms of 197 untreated adults were analyzed in dental imaging software (Onyx Ceph 3™; Image Instruments, Chemnitz, Germany). Four groups were formed based on vertical (Index scores) and sagittal (individualized ANB values) parameters. Ninety-nine patients were defined as the control group due to their neutral sagittal and vertical relationships. The remaining patients were found by their vertical relationships to represent open-bite cases and were divided by their sagittal relationships into three study groups: neutral (Class I, n = 34), distal (Class II, n = 26), and mesial (Class III, n = 38). A geometric morphometric approach was used to analyze the x,y-coordinates of 28 skeletal landmarks on each cephalogram. Relative size was captured based on centroid size (CS). The shape-determining factors in the groups were compared by permutation testing after Procrustes transformation, and intergroup differences were visualized in the form of thin-plate splines. While size (CS) was significantly increased in the Class III group, the other two groups were not different from the control group. After Procrustes transformation, characteristic and invariably significant (p common that the mandibular ramus is compressed, but marked differences are seen in terms of vertical development of the maxilla. This differentiated view of open-bite cases should be taken into consideration during individual etiology assessment and treatment planning.

  7. [Biomechanical study on dento-alveolar arch forces].

    Science.gov (United States)

    Onu, Brînduşa; Burlui, V

    2009-01-01

    This study has two major objectives. The first one is to draw attention in an original device especially conceived and designed to measure bite force; the second purpose of the study is represented by proper measurements of individual bite force during bilateral clenching for two lots of patients using this device and comparing the outcomes to those of other similar studies, in order to prove its practical utility. 62 young (20-35 years of age) healthy patients were tested: 35 fully dentured subjects in control group and 27 subjects with various single unit treated edentation, in test group. The two potentiometers from the lateral side of the device are connected to a computer which would measure, register and interpret the outcomes during three different sessions of clenching for each patient. Measured values showed that the mean maximum bilateral bite force in patients with no edentation was, in all cases, higher than in patients with single unit treated edentation for all three sessions. Because the device allows simultaneous bilateral registration of the bite force, during the same session, it is obvious that it can measure also the asymmetry between left and right dental hemi-arches. Therefore, in control group, mean values found in left side were higher (369.36N - 399.75N) than right side (352.18N - 392.15N); an opposite situation was found in test group: higher values were found in right side (313.75N - 329.43N) comparing to left side (310.54N -321.53N). The device proved to be usefull not only for measuring bite force in one region of dental arches, but it is designed to simultaneous register parameters from various regions; the values obtained in this study are similar to those reported by others authors who used more sophisticated devices, so that this simple device proves its usefulness.

  8. Pigeon tick bite

    DEFF Research Database (Denmark)

    Rolla, G; Heffler, E; Boita, M

    2018-01-01

    Anaphylaxis is a serious systemic allergic reaction with rapid onset and potentially life-threatening. We report in detail a case of severe nocturnal anaphylaxis due to pigeon tick bite showing the diagnostic value of the extract and the recombinant allergen in the diagnostic procedures (basophil...... reagents. Because of the growing number of pigeons in Middle and Southern Europe cities, some cases of idiopathic anaphylaxis could potentially be caused by A. reflexus in those countries. The identification of pigeon ticks as a trigger of anaphylaxis would greatly improve medical care and advice...

  9. Black widow spider bite.

    Science.gov (United States)

    Kobernick, M

    1984-05-01

    Latrodectus mactans has now invaded towns and cities. The spider's venom is a neurotoxin that causes little local reaction but produces pain and spasm in large skeletal muscle groups within 30 minutes to three hours after the bite. Severe envenomation may result in respiratory failure and coma. First aid is of no value. Muscle relaxants are useful in treatment, as is calcium gluconate. Antivenin is indicated for high-risk victims, such as those with hypertension and persons younger than 16 or older than 60 years of age.

  10. Large Scale Security Force Assistance: A Measured Approach

    Science.gov (United States)

    2011-02-17

    Military Assistance Training Advisory ( MATA ) course. The program of instruction (POI) for MATA evolved over time to reflect the ever changing environment...Force Assistance, v. 23 Ibid. 24 Robert D. Ramsey III, Advising Indigenous Forces: American Advisors in Korea, Vietnam, and El Salvador , (Fort

  11. Accurate measurement of microscopic forces and torques using optical tweezers

    Directory of Open Access Journals (Sweden)

    Andrew Forbes

    2011-09-01

    Full Text Available It is now well known that matter may be trapped by optical fields with high intensity gradients. Once trapped, it is then possible to manipulate microscopic particles using such optical fields, in so-called optical tweezers. Such optical trapping and tweezing systems have found widespread application across diverse fields in science, from applied biology to fundamental physics. In this article we outline the design and construction of an optical trapping and tweezing system, and show how the resulting interaction of the laser light with microscopic particles may be understood in terms of the transfer of linear and angular momentum of light. We demonstrate experimentally the use of our optical tweezing configuration for the measurement of microscopic forces and torques. In particular, we make use of digital holography to create so-called vortex laser beams, capable of transferring orbital angular momentum to particles. The use of such novel laser beams in an optical trapping and tweezing set-up allows for the control of biological species at the single-cell level.

  12. Methods for the Analysis of Human Bite Marks.

    Science.gov (United States)

    Naru, A S

    1997-12-01

    The comparison of features within a bite mark injury with the dentition of a suspect may be required during the course of a criminal investigation. A review of the literature regarding bite mark analysis has been undertaken to determine the value of this evidence. Bite marks in skin are complex injuries consisting of abrasions, lacerations, and contusions, caused by the crushing action of the teeth and related structures. Front-line investigators need to recognize and interpret these features, but no standard method of information collection or comparison has been agreed. Many classifications of bite mark types have been proposed, but do not appear to aid mark analysis. Investigations of bite strengths and sucking forces have been inconclusive. Insufficient information exists as to the accuracy and reproducibility of the representation of the dentition by tissue pathology. Histological analysis and collagen staining techniques have attempted to define the area of injury in detail, but have limited application. The quality of the mark is determined by numerous intrinsic and extrinsic factors. Distortion and shrinkage of the tissues introduce dimensional disturbances that require elimination before a comparison can be undertaken. No method exists to quantify and correct these distortions. The investigator must be aware that self-inflicted marks often occur among children and that other events may replicate bite mark injuries. The most common bite mark comparison methods employ an intermediate template produced from the suspect dentition that, when overlaid onto a scale photograph of the injury, demonstrates correspondence. No agreement exists regarding the individuality of human dentition, minimum level of correspondence required to positively identify the assailant, and the accuracy to which tissue pathology can represent these details. It is concluded that bite mark comparison can only exclude a suspect and should not be used for positive identification. Copyright

  13. A verification of quantum field theory – measurement of Casimir force

    Indian Academy of Sciences (India)

    Abstract. Here we review our work on measurement of the Casimir force between a large alu- minum coated a sphere and flat plate using an atomic force microscope. The average statistical pre- cision is 1% of the force measured at the closest separation. We have also shown nontrival boundary dependence of the Casimir ...

  14. Esthetic correction in open bite

    Directory of Open Access Journals (Sweden)

    Swapnil Parlani

    2011-01-01

    Full Text Available Deleterious oral habits, which are persistent, can lead to poor esthetics of a beautiful face. Conventional treatment modalities for an open bite usually include orthodontic treatment and/or skeletal surgery. This article focuses on a different treatment modality for an anterior open bite.

  15. Animal bite - first aid - slideshow

    Science.gov (United States)

    ... medlineplus.gov/ency/presentations/100214.htm Animal bite - first aid - series—Procedure, part 1 To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 2 Go to slide 2 out of 2 Overview To treat a minor bite, first wash your hands thoroughly with soap to avoid ...

  16. Bites and Scratches (For Parents)

    Science.gov (United States)

    ... tease or provoke any animals, even family pets. Animals should not be disturbed while they are eating or sleeping. If you own a pet, make sure it's properly immunized and licensed. Reviewed by: Larissa Hirsch, MD Date reviewed: January ... Safe Pets First Aid: Animal Bites Cat Scratch Disease Preventing Dog Bites Rabies ...

  17. Homicidal Snake Bite in Children.

    Science.gov (United States)

    Paulis, Melad G; Faheem, Ayman L

    2016-03-01

    Snake bites are common in many regions of the world. Snake envenomation is relatively uncommon in Egypt; such unfortunate events usually attract much publicity. Snake bite is almost only accidental, occurring in urban areas and desert. Few cases were reported to commit suicide by snake. Homicidal snake poisoning is so rare. It was known in ancient world by executing capital punishment by throwing the victim into a pit full of snakes. Another way was to ask the victim to put his hand inside a small basket harboring a deadly snake. Killing a victim by direct snake bite is so rare. There was one reported case where an old couple was killed by snake bite. Here is the first reported case of killing three children by snake bite. It appeared that the diagnosis of such cases is so difficult and depended mainly on the circumstantial evidences. © 2015 American Academy of Forensic Sciences.

  18. A verification of quantum field theory – measurement of Casimir force

    Indian Academy of Sciences (India)

    : F = &z where & is the force constant and z is the cantilever deflection. The cantilever is calibrated and the residual potential difference between the grounded sphere and plate is measured using the electrostatic force between them. The detail ...

  19. A measurement of the hysteresis loop in force-spectroscopy curves using a tuning-fork atomic force microscope

    Directory of Open Access Journals (Sweden)

    Manfred Lange

    2012-03-01

    Full Text Available Measurements of the frequency shift versus distance in noncontact atomic force microscopy (NC-AFM allow measurements of the force gradient between the oscillating tip and a surface (force-spectroscopy measurements. When nonconservative forces act between the tip apex and the surface the oscillation amplitude is damped. The dissipation is caused by bistabilities in the potential energy surface of the tip–sample system, and the process can be understood as a hysteresis of forces between approach and retraction of the tip. In this paper, we present the direct measurement of the whole hysteresis loop in force-spectroscopy curves at 77 K on the PTCDA/Ag/Si(111 √3 × √3 surface by means of a tuning-fork-based NC-AFM with an oscillation amplitude smaller than the distance range of the hysteresis loop. The hysteresis effect is caused by the making and breaking of a bond between PTCDA molecules on the surface and a PTCDA molecule at the tip. The corresponding energy loss was determined to be 0.57 eV by evaluation of the force–distance curves upon approach and retraction. Furthermore, a second dissipation process was identified through the damping of the oscillation while the molecule on the tip is in contact with the surface. This dissipation process occurs mainly during the retraction of the tip. It reaches a maximum value of about 0.22 eV/cycle.

  20. Thermophoretic forces on DNA measured with a single-molecule spring balance

    DEFF Research Database (Denmark)

    Pedersen, Jonas Nyvold; Lüscher, Christopher James; Marie, Rodolphe

    2014-01-01

    of the thermophoretic force in a static configuration finds forces up to 130 fN. This is eleven times stronger than the force experienced by the same molecule in the same thermal gradient in bulk, where the molecule shields itself. Our stronger forces stretch the middle of the molecule up to 80% of its contour length......We stretch a single DNA molecule with thermophoretic forces and measure these forces with a spring balance: the DNA molecule itself. It is an entropic spring which we calibrate, using as a benchmark its Brownian motion in the nanochannel that contains and prestretches it. This direct measurement...

  1. Three-axis micro-force sensor with sub-micro-Newton measurement uncertainty and tunable force range

    International Nuclear Information System (INIS)

    Muntwyler, S; Beyeler, F; Nelson, B J

    2010-01-01

    The first three-axis micro-force sensor with adjustable force range from ±20 µN to ±200 µN and sub-micro-Newton measurement uncertainty is presented. The sensor design, the readout electronics, the sensor characterization and an uncertainty analysis for the force predictions are described. A novel microfabrication process based on a double silicon-on-insulator (SOI) substrate has been developed enabling a major reduction in the fabrication complexity of multi-axis sensors and actuators.

  2. Standard practice of calibration of force-measuring instruments for verifying the force indication of testing machines

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2006-01-01

    1.1 The purpose of this practice is to specify procedures for the calibration of force-measuring instruments. Procedures are included for the following types of instruments: 1.1.1 Elastic force-measuring instruments, and 1.1.2 Force-multiplying systems, such as balances and small platform scales. Note 1Verification by deadweight loading is also an acceptable method of verifying the force indication of a testing machine. Tolerances for weights for this purpose are given in Practices E 4; methods for calibration of the weights are given in NIST Technical Note 577, Methods of Calibrating Weights for Piston Gages. 1.2 The values stated in SI units are to be regarded as the standard. Other metric and inch-pound values are regarded as equivalent when required. 1.3 This practice is intended for the calibration of static force measuring instruments. It is not applicable for dynamic or high speed force calibrations, nor can the results of calibrations performed in accordance with this practice be assumed valid for...

  3. Effects of skin elasticity on bite mark distortion.

    Science.gov (United States)

    Lewis, Cheri; Marroquin, Leonor A

    2015-12-01

    Bite marks have been reported to have an evidentiary value similar to fingerprints. We believed bite mark distortion would impact the accuracy and reliability of bite mark interpretation. Inked denture-stamps were substituted for actual bite marks and were placed onto 40 participating volunteers' shoulders. Four changes in arm position were photographed using an ABFO #2 reference scale. The measurements of individual tooth widths and intercanine distances in each position were compared. The maximum tooth width distortion observed was 53.8%, whereas the maximum intercanine distance distortion was 41.9%. Distortion was found to increase with age and weight and was non-uniform across a dental arch. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  4. Two bite mark cases with inadequate scale references.

    Science.gov (United States)

    Bernstein, M L

    1985-07-01

    Most literature addressing comparisons between epidermal bite marks and the perpetrator's bite pattern mandates fastidious coordination between the size of the compared reproductions. While ideal, this is not possible in every case and inability to control this variable in selected cases may not necessarily invalidate the comparison. The first case involves a known perpetrator. All photographic measurements were recorded with acceptable techniques to discover a serious discrepancy in arch size. The second case was degraded by the absence of a ruler in a tangentially made photograph of a bite mark. In both cases, the weight of the conclusions were lessened by these problems but the impartial handling of the evidence and explanation of discrepancies offered credibility to the analyses. Both cases illustrate that a technical infraction in processing and recording bite marks, though serious, need not automatically preempt the analysis.

  5. Water vapour and heat combine to elicit biting and biting persistence in tsetse.

    Science.gov (United States)

    Chappuis, Charles J F; Béguin, Steve; Vlimant, Michèle; Guerin, Patrick M

    2013-08-19

    Tsetse flies are obligatory blood feeders, accessing capillaries by piercing the skin of their hosts with the haustellum to suck blood. However, this behaviour presents a considerable risk as landing flies are exposed to predators as well as the host's own defense reactions such as tail flicking. Achieving a successful blood meal within the shortest time span is therefore at a premium in tsetse, so feeding until replete normally lasts less than a minute. Biting in blood sucking insects is a multi-sensory response involving a range of physical and chemical stimuli. Here we investigated the role of heat and humidity emitted from host skin on the biting responses of Glossina pallidipes, which to our knowledge has not been fully studied in tsetse before. The onset and duration of the biting response of G. pallidipes was recorded by filming movements of its haustellum in response to rapid increases in temperature and/or relative humidity (RH) following exposure of the fly to two airflows. The electrophysiological responses of hygroreceptor cells in wall-pore sensilla on the palps of G. pallidipes to drops in RH were recorded using tungsten electrodes and the ultra-structure of these sensory cells was studied by scanning and transmission electron microscopy. Both latency and proportion of tsetse biting are closely correlated to RH when accompanied by an increase of 13.1°C above ambient temperature but not for an increase of just 0.2°C. Biting persistence, as measured by the number of bites and the time spent biting, also increases with increasing RH accompanied by a 13.1°C increase in air temperature. Neurones in wall-pore sensilla on the palps respond to shifts in RH. Our results show that temperature acts synergistically with humidity to increase the rapidity and frequency of the biting response in tsetse above the levels induced by increasing temperature or humidity separately. Palp sensilla housing hygroreceptor cells, described here for the first time in tsetse

  6. Direct measurement of interaction forces between a platinum dichloride complex and DNA molecules.

    Science.gov (United States)

    Muramatsu, Hiroshi; Shimada, Shogo; Okada, Tomoko

    2017-09-01

    The interaction forces between a platinum dichloride complex and DNA molecules have been studied using atomic force microscopy (AFM). The platinum dichloride complex, di-dimethylsulfoxide-dichloroplatinum (II) (Pt(DMSO) 2 Cl 2 ), was immobilized on an AFM probe by coordinating the platinum to two amino groups to form a complex similar to Pt(en)Cl 2 , which is structurally similar to cisplatin. The retraction forces were measured between the platinum complex and DNA molecules immobilized on mica plates using force curve measurements. The histogram of the retraction force for λ-DNA showed several peaks; the unit retraction force was estimated to be 130 pN for a pulling rate of 60 nm/s. The retraction forces were also measured separately for four single-base DNA oligomers (adenine, guanine, thymine, and cytosine). Retraction forces were frequently observed in the force curves for the DNA oligomers of guanine and adenine. For the guanine DNA oligomer, the most frequent retraction force was slightly lower than but very similar to the retraction force for λ-DNA. A higher retraction force was obtained for the adenine DNA oligomer than for the guanine oligomer. This result is consistent with a higher retraction activation energy of adenine with the Pt complex being than that of guanine because the kinetic rate constant for retraction correlates to exp(FΔx - ΔE) where ΔE is an activation energy, F is an applied force, and Δx is a displacement of distance.

  7. Shrieking, Biting, and Licking

    Directory of Open Access Journals (Sweden)

    Sarah Stang

    2018-01-01

    Full Text Available This article examines examples of the monstrous-feminine in the form of abject female monsters in a selection of critically acclaimed and commercially successful video games. Various female monsters from CD Projekt RED’s The Witcher series (2007-2015, and Santa Monica Studio’s God of War series (2005-2013 are considered as examples of the abject monstrous-feminine which fall into a long tradition in horror media of making the female body and body movements into something horrific and repulsive. These female monsters use shrieking, biting, licking, and spreading disease as weapons against the male protagonist, who must slay them to restore symbolic order and progress in the games.

  8. [Protection against tick bites].

    Science.gov (United States)

    Boulanger, N; Lipsker, Dan

    2015-04-01

    There are numerous tick-borne infections, which include viral (TBE), parasitic (babesiosis) and bacterial diseases. Lyme disease (Lyme borreliosis) is the most common tick-borne disease in France. In temperate climates such as in France, ticks bite humans between March and October. Prevention relies on adequate clothing and on repellents. The latter are reviewed in this work. Repellents may be natural, made from eucalyptus, tomato and coconut, or synthetic, among which the most widely used is DEET (N,N,-Diethyl-m-toluamide). Newer, synthetic repellents exist such as IR3535 which, as well as being less toxic, also exhibits greater efficacy against ticks. Some repellents are used on the skin, while others, like permethrin, which is actually an insecticide, may be applied to clothing. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  9. Forced excitation and active control for the measurement of fluid-elastic forces

    International Nuclear Information System (INIS)

    Caillaud, Sebastien

    1999-01-01

    The action of a fluid flow on a tubes bundle is commonly decomposed into a random turbulent excitation and a fluid-elastic excitation. The fluid-elastic forces which are coupled to the tubes movement can be experimentally determined from an analysis of the vibratory response of the structure excited by turbulent forces. For low flow velocities, the turbulent excitation can be insufficient to make the tube significantly vibrate and to permit a correct vibratory analysis. On the opposite side, the structure can become unstable for high flow velocities: the fluid-elastic forces make the fluid-structure damping system fall towards zero. Two experimental methods are proposed in order to extend the considered flow rate. An additional excitation force allows to increase the tube vibration level for improving the signal-noise ratio at low velocities. When the tube is submitted to fluid-elastic instability, an artificial damping contribution by active control allows to stabilize it. Methods are implemented on a flexible tube inserted into rigid tubes bundle water and water-air transverse flows. Two actuator technologies are used: an electromagnetic exciter and piezoelectric actuators. The additional excitation method shows that the fluid-elastic forces remain insignificant at low velocity single phase flow. With the active control method, it is possible to carry out tests beyond the fluid-elastic instability. In two-phase flow, the stabilization of the structure is observed for low vacuum rates. The obtained new results are analyzed with the literature expected results in terms of fluid-elastic coupling and turbulent excitation. (author) [fr

  10. Spatially resolved frequency-dependent elasticity measured with pulsed force microscopy and nanoindentation

    NARCIS (Netherlands)

    Sweers, Kim K M; van der Werf, Kees O; Bennink, Martin L; Subramaniam, Vinod

    2012-01-01

    Recently several atomic force microscopy (AFM)-based surface property mapping techniques like pulsed force microscopy (PFM), harmonic force microscopy or Peakforce QNM® have been introduced to measure the nano- and micro-mechanical properties of materials. These modes all work at different operating

  11. Towards measurement of the Casimir force between parallel plates separated at sub-mircon distance

    NARCIS (Netherlands)

    Syed Nawazuddin, M.B.; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; Berenschot, Johan W.; de Boer, Meint J.; Elwenspoek, Michael Curt

    2011-01-01

    Ever since its prediction, experimental investigation of the Casimir force has been of great scientific interest. Many research groups have successfully attempted quantifying the force with different device geometries; however measurement of the Casimir force between parallel plates with sub-micron

  12. The big shift: measuring the forces of change

    DEFF Research Database (Denmark)

    Hagel, John; Brown, John Seely; Davison, Lang

    2009-01-01

    Traditional metrics don't capture many of the challenges and opportunities in store for U.S. companies and the national economy. The authors, from Deloitte, present a framework for understanding the forces that have transformed business over the past 40 years--and an index for gauging their impact...

  13. Femto-Newton light force measurement at the thermal noise limit.

    Science.gov (United States)

    Mueller, F; Heugel, S; Wang, L J

    2008-03-15

    The measurement of very small light forces has wide applications in many fields of physics. A common measurement method for small force detection is the determination of changes in the dynamic behavior of mechanical oscillators, either in amplitude or in frequency. The detection of slowly varying forces mostly requires long period oscillators, such as a torsion pendulum. We demonstrate the application of a macroscopic, low-noise, torsion balance oscillator for the detection of radiation pressure forces at the femto-Newton level. The system is "precooled" (removing excess seimic noise) to be only thermal noise limited. The demonstrated force sensitivity reaches the thermal limit.

  14. Chewing pattern and muscular activation in open bite patients.

    Science.gov (United States)

    Piancino, Maria Grazia; Isola, Gaetano; Merlo, Andrea; Dalessandri, Domenico; Debernardi, Cesare; Bracco, Pietro

    2012-04-01

    Different studies have indicated, in open bite patients, that masticatory muscles tend to generate a small maximum bite force and to show a reduced cross-sectional area with a lower EMG activity. The aim of this study was to evaluate the kinematics parameters of the chewing cycles and the activation of masseters and anterior temporalis muscles of patients with anterior dental open bite malocclusion. There have been no previous reports evaluating both kinematic values and EMG activity of patients with anterior open bite during chewing. Fifty-two young patients (23 boys and 29 girls; mean age±SD 11.5±1.2 and 10.2±1.6years, respectively) with anterior open bite malocclusion and 21 subjects with normal occlusion were selected for the study. Kinematics parameters and surface electromyography (EMG) were simultaneously recorded during chewing a hard bolus with a kinesiograph K7-I Myotronics-Usa. The results showed a statistically significant difference between the open bite patients and the control group for a narrower chewing pattern, a shorter total and closing duration of the chewing pattern, a lower peak of both the anterior temporalis and the masseter of the bolus side. In this study, it has been observed that open bite patients, lacking the inputs from the anterior guidance, that are considered important information for establishing the motor scheme of the chewing pattern, show narrower chewing pattern, shorter lasting chewing cycles and lower muscular activation with respect to the control group. Published by Elsevier Ltd.

  15. Dog Bite Rates and Biting Dog Breeds in Texas, 1995-1997

    National Research Council Canada - National Science Library

    Blocker, David

    2000-01-01

    .... The first aim of this study was to summarize descriptive characteristics of biting dogs and dog bite victims in Texas from 1995 through 1997 using the Texas Department of Health severe animal bite...

  16. Reversible myocarditis after spider bite.

    Science.gov (United States)

    Kara, Hasan; Ak, Ahmet; Bayir, Aysegul; Avci, Ahmet

    2013-04-08

    Black widow spiders (Latrodectus tredecimguttatus) are poisonous spiders endemic in Turkey. Latrodectus bites may cause myocarditis with increased cardiac enzymes. We treated two men (aged 20 and 33 years) who had myocarditis after black spider bites with leucocytosis and elevated levels of troponin I, creatine kinase and creatine kinase-MB fraction. Both patients had normal results on an ECG, and one patient had abnormal echocardiography with minimal left ventricular wall movement disorder. Both patients were hospitalised in the intensive care unit and treated with intravenous fluids, analgesics, spasmolytic drugs, tetanus prophylaxis and cardiac monitoring. The levels of troponin I, creatine kinase and creatine kinase-MB fraction improved, and the patients were discharged home on the third and fifth hospital day without complications. Myocarditis after a Latrodectus bite is rare, but may be associated with serious complications. Therefore, in regions endemic with Latrodectus spiders, prudent treatment of spider bites may include cardiac evaluation and monitoring.

  17. Tips to Prevent Tick Bites

    Science.gov (United States)

    Using the right insect repellent and other preventive actions can discourage ticks, mosquitoes, and other biting insects from landing on you. Tips include avoiding tick habitats and minimizing exposed skin.

  18. Biting. ERIC/EECE Report.

    Science.gov (United States)

    Cesarone, Bernard

    2003-01-01

    This column summarizes recent ERIC documents and journal articles, and highlights some World Wide Web resources, that discuss issues related to the problem of children biting in preschool. (Contains 13 annotated summaries.) (SD)

  19. Human bites of the face

    African Journals Online (AJOL)

    involved (90.9%). This was also reported by Muguti et al.3. (29%) and Iregbulem4 (100%). The upper lip was not involved in the present study, and only few series have reported bites to this site - Muguti et al." (5%) and Venter" (7.0%). Iregbulem4 believes that trying to bite off the lip is a subconscious effort to attack and thus.

  20. Quantum limited force measurement in a cavityless optomechanical system

    International Nuclear Information System (INIS)

    Fermani, Rachele; Mancini, Stefano; Tombesi, Paolo

    2004-01-01

    We study the possibility of revealing a weak coherent force by using a pendular mirror as a probe, and coupling this to a radiation field, which acts as the meter, in a cavityless configuration. We determine the sensitivity of such a scheme and show that the use of an entangled meter state greatly improves the ultimate detection limit. We also compare this scheme with that involving an optical cavity

  1. Measuring forces in liver cutting: new equipment and experimental results.

    Science.gov (United States)

    Chanthasopeephan, Teeranoot; Desai, Jaydev P; Lau, Alan C W

    2003-12-01

    We are interested in modeling the liver cutting process as accurately as possible by determining the mechanical properties experimentally and developing a predictive model that is self-consistent with the experimentally determined properties. In this paper, we present the newly developed hardware and software to characterize the mechanical response of pig liver during (ex vivo) cutting. We describe the custom-made cutting apparatus, the data acquisition system, and the characteristics of the cutting force versus displacement plot. The force-displacement behavior appears to reveal that the cutting process consists of a sequence of intermittent localized crack extension in the tissue on the macroscopic scale. The macroscopic cutting force-displacement curve shows repeating self-similar units of localized linear loading followed by sudden unloading. The sudden unloading coincides with observed onset of localized crack growth. This experimental data were used to determine the self-consistent local effective Young's modulus for the specimens, to be used in finite element models. Results from finite element analyses models reveal that the magnitude of the self-consistent local effective Young's modulus determined by plane-stress and plane-strain varies within close bounds. Finally, we have also observed that the local effective Young's modulus determined by plane stress and plane strain analysis decreases with increasing cutting speed.

  2. Measurement strategy and analytic model to determine firing pin force

    Science.gov (United States)

    Lesenciuc, Ioan; Suciu, Cornel

    2016-12-01

    As illustrated in literature, ballistics is a branch of theoretical mechanics, which studies the construction and working principles of firearms and ammunition, their effects, as well as the motions of projectiles and bullets1. Criminalistics identification, as part of judiciary identification represents an activity aimed at finding common traits of different objects, objectives, phenomena and beings, but more importantly, traits that differentiate each of them from similar ones2-4. In judicial ballistics, in the case of rifled firearms it is relatively simple for experts to identify the used weapon from traces left on the projectile, as the rifling of the barrel leaves imprints on the bullet, which remain approximately identical even after the respective weapon is fired 100 times with the same barrel. However, in the case of smoothbore firearms, their identification becomes much more complicated. As the firing cap suffers alterations from being hit by the firing pin, determination of the force generated during impact creates the premises for determining the type of firearm used to shoot the respective cartridge. The present paper proposes a simple impact model that can be used to evaluate the force generated by the firing pin during its impact with the firing cap. The present research clearly showed that each rifle, by the combination of the three investigated parameters (impact force maximum value, its variation diagram, and impact time) leave a unique trace. Application of such a method in ballistics can create the perspectives for formulating clear conclusions that eliminate possible judicial errors in this field.

  3. Estimation of Cable Forces of a Guyed Mast from Dynamic Measurements

    DEFF Research Database (Denmark)

    Kirkegaard, Poul Henning; Hansen, Lars Pilegaard

    This paper presents how the tension forces in the cables of a 200 m. high guyed mast have been estimated from natural frequencies obtained from acceleration measurements.The mast is guyed at five levels with three guys at 120 degree intervals at each level. The accelerations in three directions...... were measured in five cables. The relationship between frequencies and cable forces have been establish assuming the cables to behave in linear manner. The results show that estimated cables forces correspond very well to the expected. The results obtained showed that it was possible to obtain reliable...... estimates for cables forces based on measured natural frequencies....

  4. Measurement and calculation of forces in a magnetic journal bearing actuator

    Science.gov (United States)

    Knight, Josiah; Mccaul, Edward; Xia, Zule

    1991-01-01

    Numerical calculations and experimental measurements of forces from an actuator of the type used in active magnetic journal bearings are presented. The calculations are based on solution of the scalar magnetic potential field in and near the gap regions. The predicted forces from single magnet with steady current are compared with experimental measurements in the same geometry. The measured forces are smaller than calculated ones in the principal direction but are larger than calculated in the normal direction. This combination of results indicate that material and spatial effects other than saturation play roles in determining the force available from an actuator.

  5. Thermally activated state transition technique for femto-Newton-level force measurement.

    Science.gov (United States)

    Chen, Feng-Jung; Wong, Jhih-Sian; Hsu, Ken Y; Hsu, Long

    2012-05-01

    We develop and test a thermally activated state transition technique for ultraweak force measurement. As a force sensor, the technique was demonstrated on a classical Brownian bead immersed in water and restrained by a bistable optical trap. A femto-Newton-level flow force imposed on this sensor was measured by monitoring changes in the transition rates of the bead hopping between two energy states. The treatment of thermal disturbances as a requirement instead of a limiting factor is the major feature of the technique, and provides a new strategy by which to measure other ultraweak forces beyond the thermal noise limit.

  6. Validating Future Force Performance Measures (Army Class): Concluding Analyses

    Science.gov (United States)

    2016-06-01

    Opportunities Measures an individual’s preference for work that affords opportunities to lead others. Leisure Time Measures an individual’s preference...Orientation Measures an individual’s preference for working closely with others. Travel Measures an individual’s preference for work involving...frequent or regular travel . Variety Measures an individual’s preference for work involving having something different to do every day. B -1

  7. System for measurement of interaction forces between wheel and rail for railway vehicles

    Directory of Open Access Journals (Sweden)

    Manea Ion

    2017-01-01

    Full Text Available Determination of the interaction forces between wheel and rail of railway vehicles is essential for assessment of the vehicle dynamic characteristics from point of view of running safety and rail loading as well as for approval the vehicle and alignment them to the Technical Specification for Interoperability. The direct measurement of transverse and vertical interaction forces using the existing full-disk wheel is practical impossible due to the impossibility of separating the two types of forces. To avoid this impediment it was realized a measuring wheelset fitted with 12 spokes achieved as force transducers for measurement of the vertical forces and 12 spokes achieved as force transducers for measurement of the transverse forces. The measuring wheelset was calibrated as a force transducer and was used to determine the wheel and rail interaction forces for LE-MA 6000kW electric locomotive made by Softronic Craiova. The article presents the measuring wheelset, the calibration principle and the calibration characteristics as well as some time history of the main parameters which characterize the running safety and rail loading, determined in the on-track tests.

  8. Force sensor for measuring power transfer between the human body and the environment

    NARCIS (Netherlands)

    Brookhuis, Robert Anton; Lammerink, Theodorus S.J.; Wiegerink, Remco J.; de Boer, Meint J.; Elwenspoek, Michael Curt

    2011-01-01

    A force sensor with capacitive readout is designed and realized for the measurement of mechanical power transfer. The ultimate aim is to integrate this in a glove that determines the complete mechanical interaction between the human hand and the environment. The sensor measures the normal force and

  9. Direct Measurements of Surface Energy, Elastic Modulus and Interparticle Forces of Titan Aerosol Analog (`Tholin') Using Atomic Force Microscopy

    Science.gov (United States)

    Yu, X.; Horst, S. M.; He, C.; McGuiggan, P.; Bridges, N. T.

    2017-12-01

    To understand the origin of the dunes on Titan, it is important to investigate the material properties of the sand particles on Titan, which are mainly made of organics deposited from the atmosphere [1]. The organic sand may behave differently compared to the quartz/basaltic sand on terrestrial planets (Earth, Venus, Mars) in terms of interparticle forces. We measured the surface energy (through contact angle measurements) and elastic modulus (through Atomic Force Microscopy, AFM) of Titan aerosol analog (tholins) produced in our lab. Tholins may be compositionally similar to sand on Titan. We directly measured the interparticle forces between a tholin particle adhered to an AFM cantilver and tholin particles on a substrate. We also measured the properties of walnut shells, a typical material used in the Titan Wind Tunnel (TWT, [2, 3]). We find the surface energy of a tholin thin film is about 70.9 mN/m and its elastic modulus is about 3.5 GPa (similar to hard polymers like PMMA and polystyrene). We used the two measured material properties of tholin to calculate its interparticle cohesion assuming simple sphere-sphere geometry [4]. For two 20 µm particles, the theoretical cohesion force is about 6682 nN. Under dry nitrogen (RHmeasured interparticle forces using AFM was approximately 4000 nN, which is smaller than theoretical predictions but still relatively strong under dry conditions. The interparticle cohesion between walnut shell particles is only 200 nN, which is much lower than between tholin particles. The key finding of this study is that the interparticle cohesion forces are much larger for tholins and presumably Titan sand particles than for terrestrial sand and materials used in the wind tunnel. This suggests we should increase the interparticle force in both analog experiments (TWT) and threshold models (e.g. [5]) to correctly translate the results to real Titan conditions. The strong cohesion of tholins may also inform us how the small aerosol

  10. Fiber Bragg grating sensor for simultaneous measurement of temperature and force using polymer open loop

    Science.gov (United States)

    Huang, Yonglin; Zhang, Shiyan

    2014-07-01

    A fiber Bragg grating (FBG) sensor for simultaneous measurement of temperature and force is proposed and demonstrated. Where a part of uniform FBG (about one half length of an FBG) is attached on the polymer open loop, the FBG is divided into two parts which has an equal length. So the two parts can be regarded as two FBGs. Because of the difference of the Young's modulus and the thermal expansion coefficients for two parts of the FBG, the two Bragg reflection wavelengths are shift when the temperature and force are applied on the sensor. Simultaneous measurement of temperature and force is demonstrated experimentally. The experimental results show that the linear response to temperature and force are achieved. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. This study provides a simple and economical method to measure temperature and force simultaneously.

  11. Bite through the tent.

    Science.gov (United States)

    Naue, Jana; Lutz-Bonengel, Sabine; Pietsch, Klaus; Sänger, Timo; Schlauderer, Nicola; Schmidt, Ulrike

    2012-05-01

    The authors report on a young boy who was bitten into his face by an unknown animal while being asleep in a tent. Given the bite marks and the location of the scene, members of the mustelidae and canidae families were the first "suspects." Deoxyribunucleic acid (DNA) recovered from the tent's wall was analyzed with regard to parts of the mitochondrial 12S ribosomal ribunucleic acid (12S rRNA) and cytochrome b (cytb) genes as well as nuclear short tandem repeats (STRs). Since Sanger sequencing revealed a mixed sequence with a strong human component overlying the nonhuman contributor, an animal screening using a duplex real-time polymerase chain reaction (PCR) with an intercalating dye and melt curve analysis was employed. The results were later confirmed by cloning. The applied commercial canine STR kit verified the animal family (canidae) but did not help in discriminating the species due to cross-species amplification. In the presented case, the real-time PCR assay offered the cheapest and fastest method for animal family determination, which then allowed for an appropriate and sample-saving strategy to characterize the causative animal species.

  12. Measurement of cell adhesion force by vertical forcible detachment using an arrowhead nanoneedle and atomic force microscopy

    International Nuclear Information System (INIS)

    Ryu, Seunghwan; Hashizume, Yui; Mishima, Mari; Kawamura, Ryuzo; Tamura, Masato; Matsui, Hirofumi; Matsusaki, Michiya; Akashi, Mitsuru; Nakamura, Chikashi

    2014-01-01

    Graphical abstract: - Highlights: • We developed a method to measure cell adhesion force by detaching cell using an arrowhead nanoneedle and AFM. • A nanofilm consisting of fibronectin and gelatin was formed on cell surface to reinforce the cell cortex. • By the nanofilm lamination, detachment efficiencies of strongly adherent cell lines were improved markedly. - Abstract: The properties of substrates and extracellular matrices (ECM) are important factors governing the functions and fates of mammalian adherent cells. For example, substrate stiffness often affects cell differentiation. At focal adhesions, clustered–integrin bindings link cells mechanically to the ECM. In order to quantitate the affinity between cell and substrate, the cell adhesion force must be measured for single cells. In this study, forcible detachment of a single cell in the vertical direction using AFM was carried out, allowing breakage of the integrin–substrate bindings. An AFM tip was fabricated into an arrowhead shape to detach the cell from the substrate. Peak force observed in the recorded force curve during probe retraction was defined as the adhesion force, and was analyzed for various types of cells. Some of the cell types adhered so strongly that they could not be picked up because of plasma membrane breakage by the arrowhead probe. To address this problem, a technique to reinforce the cellular membrane with layer-by-layer nanofilms composed of fibronectin and gelatin helped to improve insertion efficiency and to prevent cell membrane rupture during the detachment process, allowing successful detachment of the cells. This method for detaching cells, involving cellular membrane reinforcement, may be beneficial for evaluating true cell adhesion forces in various cell types

  13. Development and validation of a method to directly measure the cable force during the hammer throw.

    Science.gov (United States)

    Brice, Sara M; Ness, Kevin F; Rosemond, Doug; Lyons, Keith; Davis, Mark

    2008-05-01

    The development of cable force during hammer-throw turns is crucial to the throw distance. In this paper, we present a method that is capable of measuring cable force in real time and, as it does not interfere with technique, it is capable of providing immediate feedback to coaches and athletes during training. A strain gauge was mounted on the wires of three hammers to measure the tension in the wire and an elite male hammer thrower executed three throws with each hammer. The output from the gauges was recorded by a data logger positioned on the lower back of the thrower. The throws were captured by three high-speed video cameras and the three-dimensional position of the hammer's head was determined by digitizing the images manually. The five best throws were analysed. The force acting on the hammer's head was calculated from Newton's second law of motion and this was compared with the force measured via the strain gauge. Qualitatively the time dependence of the two forces was essentially the same, although the measured force showed more detail in the troughs of the force-time curves. Quantitatively the average difference between the measured and calculated forces over the five throws was 76 N, which corresponds to a difference of 3.8% for a cable force of 2000 N.

  14. Bites and stings: epidemiology and treatment.

    Science.gov (United States)

    Krau, Stephen D

    2013-06-01

    Rapid and effective treatment of bites is a major variable in the overall outcome of a patient who is a victim of a bite. There are a wide range of animals that bite and sting, and the reactions vary depending on the individual and the animal involved. Although most bites are treated on an outpatient basis, patients who have severe complications related to bites become patients in critical care settings. An overview of potential bite and sting sources, with some general guidelines for what to expect and how to treat the patient, is presented. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Measurement of Giardia lamblia adhesion force using an integrated microfluidic assay.

    Science.gov (United States)

    Lu, Ling; Zheng, Guo-Xia; Yang, Yu-Suo; Feng, Cheng-Yu; Liu, Fang-Fang; Wang, Yun-Hua

    2017-02-01

    The mechanisms how Giardias attach to the intestinal epithelium remain unclear. None of the methods currently being used to measure the attachment force could provide a continuous nutrition supply and a micro-aerobic atmosphere to the Giardia. Besides, they are all labor-intensive. In the present research, a microfluidic method based on electric circuit analogy was developed. The input fluid flowed through the inlet channel with different lengths and was distributed in four assay chambers. Shear force gradients were generated in chambers, too. This allowed an easy control of fluids and the shear forces. Most importantly, the shear stress large enough to detach Giardia could be generated in laminar flow regime. Moreover, analysis could be accomplished in one single test. By applying inlet flow rates of 30, 60, and 120 μL ml -1 , shear force gradients ranging from 19.47 to 60.50 Pa were generated. The adhesion forces of trophozoites were analyzed and the EC 50 of the force that caused 50% trophozoites detachment was calculated as 36.60 Pa. This paper presents a novel method for measurement of Giardia adhesion force. Graphical Abstract Measurement of Giardia adhesion force. Various of flow rates were applied to generate different shear forces and Giardia trophozoites remaining attached were counted (a-c). The percentages of attachment vs shear stress were plotted and the EC 50 of adhesion force was calculated (d).

  16. Method to measure the force to pull and to break pin bones of fish.

    Science.gov (United States)

    Balaban, Murat O; Jie, Hubert; Yin Yee, Yin; Alçiçek, Zayde

    2015-02-01

    A texture measurement device was modified to measure the force required to pull pin bones from King salmon (Oncorhynchus tshawytscha), snapper (Pagrus auratus), and kahawai (Arripis trutta). Pulled bones were also subjected to tension to measure the breaking force. For all fish, the pulling force depended on the size of the fish, and on the length of the pin bone (P bones. For example, fresh small salmon (about 1500 g whole) required 600 g on average to pull pin bones, and large fish (about 3700 g whole) required 850 g. Longer bones required greater pulling force. The breaking force followed the same trend. In general, the breaking force was greater than the pulling force. This allows the removal of the bones without breaking them. There was no statistically significant (P > 0.05) difference between the forces (both pulling and breaking) from fresh and frozen/thawed samples, although in general frozen/thawed samples required less force to pull. With the quantification of pulling and breaking forces for pin bones, it is possible to design and build better, "more intelligent" pin bone removal equipment. © 2015 Institute of Food Technologists®

  17. A wearable force plate system for the continuous measurement of triaxial ground reaction force in biomechanical applications

    International Nuclear Information System (INIS)

    Liu, Tao; Inoue, Yoshio; Shibata, Kyoko

    2010-01-01

    The ambulatory measurement of ground reaction force (GRF) and human motion under free-living conditions is convenient, inexpensive and never restricted to gait analysis in a laboratory environment and is therefore much desired by researchers and clinical doctors in biomedical applications. A wearable force plate system was developed by integrating small triaxial force sensors and three-dimensional (3D) inertial sensors for estimating dynamic triaxial GRF in biomechanical applications. The system, in comparison to existent systems, is characterized by being lightweight, thin and easy-to-wear. A six-axial force sensor (Nitta Co., Japan) was used as a verification measurement device to validate the static accuracy of the developed force plate. To evaluate the precision during dynamic gait measurements, we compared the measurements of the triaxial GRF and the center of pressure (CoP) by using the developed system with the reference measurements made using a stationary force plate and an optical motion analysis system. The root mean square (RMS) differences of the two transverse components (x- and y-axes) and the vertical component (z-axis) of the GRF were 4.3 ± 0.9 N, 6.0 ± 1.3 N and 12.1 ± 1.1 N, respectively, corresponding to 5.1 ± 1.1% and 6.5 ± 1% of the maximum of each transverse component and 1.3 ± 0.2% of the maximum vertical component of GRF. The RMS distance between the two systems' CoP traces was 3.2 ± 0.8 mm, corresponding to 1.2 ± 0.3% of the length of the shoe. Moreover, based on the results of the assessment of the influence of the system on natural gait, we found that gait was almost never affected. Therefore, the wearable system as an alternative device can be a potential solution for measuring CoP and triaxial GRF in non-laboratory environments

  18. Bug bites and stings: When to see a dermatologist

    Medline Plus

    Full Text Available ... Tips to prevent and treat bug bites Although most bug bites are harmless, some can spread dangerous ... one’s greatest efforts, bug bites still happen. Fortunately, most bug bites and stings can be safely treated ...

  19. AFM measurements of adhesive forces between carbonaceous particles and the substrates

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Tianqi [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Peng, Wei, E-mail: pengwei@tsinghua.edu.cn [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Shen, Ke [Institute of Nuclear and New Energy Technology of Tsinghua University, Collaborative Innovation Center of Advanced Nuclear Energy Technology, Key Laboratory of Advanced Reactor Engineering and Safety of Ministry of Education, Beijing 100084 (China); Yu, Suyuan, E-mail: suyuan@tsinghua.edu.cn [Center for Combustion Energy, Key Laboratory for Thermal Science and Power Engineering of Ministry of Educations, Department of Thermal Engineering, Tsinghua University, Beijing 100084 (China)

    2015-11-15

    Highlights: • Adhesive force of spherical carbonaceous particle MCMBs and HTR-10 graphite matrix debris were measured for the first time. • The measured equivalent works of adhesion were much smaller than the ideal values. • The shape factor and the particle morphology reduce the adhesive force. • The adhesion effect does not change directly with the asperity size. - Abstract: Graphite dust is carbonaceous particles generated during operation of High Temperature Gas-Cooled Reactors (HTR). Graphite dust resuspension is the key behavior associated with HTR source term analyses and environmental safety assessment. The adhesive force is the key factor that determines the resuspension rate. The present study used an atomic force microscope (AFM) to measure the adhesive force between a single carbonaceous particle and the substrate. The measurements were performed on mica, graphite IG110 and Inconel 800H. The prepared “probe cantilevers” were mesocarbon microbeads (MCMB), fuel element debris from HTR-10 and graphite NBG18. The equivalent work of adhesion was derived from the measured adhesive force and calculated based on substrate profile approximation and the JKR theoretical model. The measured work was smaller than the ideal work of adhesion, most likely due to the rough particle morphology and the rough substrate surface. Additionally, a shape factor imposes a constraint on the lateral deformation of the particles. Furthermore, surface roughness could reduce the adhesive force some depending on the particle size. Once the particle was too small to be trapped into a trough, the adhesive force would not be further reduced.

  20. Detailed On-Water Measurements of Blade Forces and Stroke Efficiencies in Sprint Canoe

    Directory of Open Access Journals (Sweden)

    Stephen Tullis

    2018-03-01

    Full Text Available Measurements of blade forces are made using a load cell mounted between the blade and shaft of a modified paddle. All six force components and moments are measured simultaneously to give a full picture of blade hydrodynamic forces as the centre of pressure on the blade varies throughout the stroke. Blade orientation was also measured using inertial measurement units, one on the blade shaft, and the other on the canoe giving the relative position of blade with respect to the boat, as well as boat speed, acceleration and motion. Testing of the instrumented paddle was undertaken by one of the authors, an ex-national team athlete. The measured forces (and propulsive/vertical forces are analyzed in detail through the stroke and as stroke averages. Various measures of propulsive efficiency are proposed using either the input force and propulsive force, or using input force and boat speed, and can be used for stroke analysis, or as training tools/targets.

  1. Traceability of small force measurements and the future international system of units (SI

    Directory of Open Access Journals (Sweden)

    Khelifa Naceur-Eddine

    2016-01-01

    Full Text Available The unit of force is connected to the international prototype of the kilogramme, unit of mass in the international system of units (SI, via dead weight machines using calibrated masses. However, forces below 10 μN, ubiquitous in nature and in some devices cannot be measured with a traceability to the SI. The measurement, with the uncertainty of these forces has implications for both basic and applied science. Today, many emerging sectors in micro/nanotechnology and biotechnology have started producing and using systems to implement low forces that, for various reasons, require them to be traceable. Also, the revision of the SI, scheduled for 2018 year, of linking the definitions of the kilogramme, the ampere, the kelvin and the mole to fixed numerical values of fundamental constants, has aroused particular interest in the measurement and calibration of small forces. In this paper, we will give some indications of the state of the art on the small force with a focus on the development of a force sensor using a photoelastic crystal as a monolithic solid-state laser. Basically, the force to be measured is applied to the crystal induces a birefringence in the laser medium which in turn manifests itself by the appearance of a splitting between the frequencies associated with the two polarization components of the oscillating laser mode. This difference is then exploited because, within the elastic limit of the crystal, it is proportional to the force acting on the laser.

  2. Hydrophobic attraction as revealed by AFM force measurements and molecular dynamics simulation.

    Science.gov (United States)

    Fa, Keqing; Nguyen, Anh V; Miller, Jan D

    2005-07-14

    Spherical calcium dioleate particles ( approximately 10 mum in diameter) were used as AFM (atomic force microscope) probes to measure interaction forces of the collector colloid with calcite and fluorite surfaces. The attractive AFM force between the calcium dioleate sphere and the fluorite surface is strong and has a longer range than the DLVO (Derjaguin-Landau-Verwey-Overbeek) prediction. The AFM force between the calcium dioleate sphere and the mineral surfaces does not agree with the DLVO prediction. Consideration of non-DLVO forces, including the attractive hydrophobic force and the repulsive hydration force, was necessary to explain the experimental results. The non-DLVO interactions considered were justified by the different interfacial water structures at calcite- and fluorite-water interfaces as revealed by the numerical computation experiments with molecular dynamics simulation.

  3. Classifying Force Spectroscopy of DNA Pulling Measurements Using Supervised and Unsupervised Machine Learning Methods.

    Science.gov (United States)

    Karatay, Durmus U; Zhang, Jie; Harrison, Jeffrey S; Ginger, David S

    2016-04-25

    Dynamic force spectroscopy (DFS) measurements on biomolecules typically require classifying thousands of repeated force spectra prior to data analysis. Here, we study classification of atomic force microscope-based DFS measurements using machine-learning algorithms in order to automate selection of successful force curves. Notably, we collect a data set that has a testable positive signal using photoswitch-modified DNA before and after illumination with UV (365 nm) light. We generate a feature set consisting of six properties of force-distance curves to train supervised models and use principal component analysis (PCA) for an unsupervised model. For supervised classification, we train random forest models for binary and multiclass classification of force-distance curves. Random forest models predict successful pulls with an accuracy of 94% and classify them into five classes with an accuracy of 90%. The unsupervised method using Gaussian mixture models (GMM) reaches an accuracy of approximately 80% for binary classification.

  4. Using optical tweezers for measuring the interaction forces between human bone cells and implant surfaces: System design and force calibration

    International Nuclear Information System (INIS)

    Andersson, Martin; Madgavkar, Ashwin; Stjerndahl, Maria; Wu, Yanrong; Tan, Weihong; Duran, Randy; Niehren, Stefan; Mustafa, Kamal; Arvidson, Kristina; Wennerberg, Ann

    2007-01-01

    Optical tweezers were used to study the interaction and attachment of human bone cells to various types of medical implant materials. Ideally, the implant should facilitate cell attachment and promote migration of the progenitor cells in order to decrease the healing time. It is therefore of interest, in a controlled manner, to be able to monitor the cell adhesion process. Results from such studies would help foresee the clinical outcome of integrating medical implants. The interactions between two primary cell culture models, human gingival fibroblasts and bone forming human osteoblast cells, and three different implant materials, glass, titanium, and hydroxyapatite, were studied. A novel type of optical tweezers, which has a newly designed quadrant detector and a powerful 3 W laser was constructed and force calibrated using two different methods: one method in which the stiffness of the optical trap was obtained by monitoring the phase lag between the trap and the moved object when imposing a forced oscillation on the trapped object and another method in which the maximum trapping force was derived from the critical velocity at which the object escapes the trap. Polystyrene beads as well as cells were utilized for the calibrations. This is the first time that cells have been used directly for these types of force calibrations and, hence, direct measurements of forces exerted on cells can be performed, thus avoiding the difficulties often encountered when translating the results obtained from cell measurements to the calibrations obtained with reference materials. This more straightforward approach represents an advantage in comparison to established methods

  5. Measurement of Multiple Blade Rate Unsteady Propeller Forces

    Science.gov (United States)

    1990-05-01

    with PUF -2 prediction ...................................... 33 17. Total velocity measurement positions using LDV .................... 34 18...CRAW F OrIC TAB Q Propeller torque JU.tSw riced .,) Qn Amplitude of nth harmonic of torque By R Propeller tip radius Ot Itt:ic A.tdt 4Vt,.*, Cc#eS r...unsteady lifting surface theory code PUF -2, 3 and were compared with measured data. PUF -2 calculations were performed for both Propellers 4132 and

  6. A Modernized UDM-600 Dynamometer-Based Setup for the Cutting Force Measurement

    Directory of Open Access Journals (Sweden)

    Ya. I. Shuliak

    2016-01-01

    Full Text Available The article considers development of a modernized UDM-600 dynamometer-based setup for measuring the cutting force components. Modernization of existing equipment to improve the method of recording the cutting force components in the automated mode is of relevance. The measuring setup allows recording the cutting force components in turning and milling, as well as the axial force and the torque in the drilling and milling operations.The article presents a block diagram and a schematic diagram of the setup to measure the cutting force components, and describes a basic principle of measuring units within the modernized setup. The developed setup uses a half-bridge strain gauge measuring circuit to record the cutting forces. To enhance the measuring circuit output voltage is used a 16-channel amplifier of LA-UN16 model with a discretely adjustable gain. To record and process electrical signals is used a data acquisition device of NI USB-6009 model, which enables transmitting the received data to a PC via USB-interface. The data acquisition device has a built-in stabilized DC power supply that is used to power the strain gauge bridges. A developed schematic diagram of the measuring setup allows us to realize this measuring device and implement its modernization.Final processing of recorded data is provided through the software developed in visual programming environment LabVIEW 9.0. The program allows us to show the real-time measuring values of the cutting force components graphically and to record the taken data to a text file.The measuring setup modernization enabled increasing measurement accuracy and reducing time for processing and analysis of experimental data obtained when measuring the cutting force components. The MT2 Department of BMSTU uses it in education and research activities and in experimental efforts and laboratory classes.

  7. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... archive Advocacy Action Center News Advocacy priorities AADA Health ... biting typically begins in childhood and can continue through adulthood, and the side effects can be more than cosmetic. Repeated nail biting ...

  8. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... biting your nails Nail biting typically begins in childhood and can continue through adulthood, and the side ... Team Patients Patient advocates Media Advertisers Quick links About AAD Support AAD Donate Shop AAD Product catalog ...

  9. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Spending money to keep your nails looking attractive may make you less likely to bite them. Alternatively, ... Just knowing when you’re inclined to bite may help solve the problem. Try to gradually stop ...

  10. First Aid: Insect Stings and Bites

    Science.gov (United States)

    ... a known severe allergy to a stinging or biting insect injectable epinephrine (EpiPen) was used the site ... Insect Repellents With DEET Safe for Kids? Bug Bites and Stings Can I Use Bug Killers and Repellents During ...

  11. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... biting your nails Nail biting typically begins in childhood and can continue through adulthood, and the side ... set of nails, such as your thumb nails, first. When that’s successful, eliminate your pinky nails, pointer ...

  12. Outdoor biting by Anopheles mosquitoes on Bioko Island does not currently impact on malaria control.

    Science.gov (United States)

    Bradley, John; Lines, Jo; Fuseini, Godwin; Schwabe, Christopher; Monti, Feliciano; Slotman, Michel; Vargas, Daniel; Garcia, Guillermo; Hergott, Dianna; Kleinschmidt, Immo

    2015-04-21

    There have been many recent reports that the rate of outdoor biting by malaria vectors has increased. This study examined the impact this might have on malaria transmission by assessing the association between exposure to outdoor bites and malaria infection on Bioko Island, Equatorial Guinea. Responses to questions about time spent outside the previous night from a malaria indicator survey were combined with human landing catch measurements of hourly rates of outdoor and indoor biting for the whole island to estimate the number of outdoor and indoor bites received by each survey respondent. The association between RDT measured malaria infection status of individuals and outdoor bites received was investigated. The average number of bites received per person per night was estimated as 3.51 in total, of which 0.69 (19.7%) would occur outdoors. Malaria infection was not significantly higher in individuals who reported spending time outside between 7 pm and 6 am the previous night compared to those not spending time outside in both adults (18.9% vs 17.4%, p = 0.20) and children (29.2% vs 27.1%, p = 0.20). Malaria infection in neither adults (p = 0.56) nor in children (p = 0.12) was associated with exposure to outdoor bites, even after adjusting for confounders. Malaria vector mosquitoes in Bioko do bite humans outdoors, and this has the potential to reduce the effectiveness of vector control. However, outdoor biting is currently not a major factor influencing the malaria burden, mainly because more than 95% of the population are indoors during the middle of the night, which is the peak biting period for malaria vector mosquitoes. The majority of resources should remain with control measures that target indoor biting and resting such as LLINs and IRS.

  13. Update: Partnership for the Revitalization of National Wind Tunnel Force Measurement Technology Capability

    Science.gov (United States)

    Rhew, Ray D.

    2010-01-01

    NASA's Aeronautics Test Program (ATP) chartered a team to examine the issues and risks associated with the lack of funding and focus on force measurement over the past several years, focusing specifically on strain-gage balances. NASA partnered with the U.S. Air Force's Arnold Engineering Development Center (AEDC) to exploit their combined capabilities and take a national level government view of the problem and established the National Force Measurement Technology Capability (NFMTC) project. This paper provides an update on the team's status for revitalizing the government's balance capability with respect to designing, fabricating, calibrating, and using the these critical measurement devices.

  14. Rope test may indicate efficacy of tail-biting treatments in growing pigs

    NARCIS (Netherlands)

    Bracke, M.B.M.

    2009-01-01

    Tail biting is a most serious welfare problem in pigs raised for slaughter. In instances of an outbreak of tail biting, scientists have recommended that farmers take measures such as removal of affected animals, provision of enrichment materials and application of repellents to the pigs' tails.

  15. Time, tire measurements forces and moments: a new standard for steady state cornering tyre testing

    NARCIS (Netherlands)

    Oosten, J.J.M. van; Savi, C.; Augustin, M.; Bouhet, O.; Sommer, J.; Colinot, J.P.

    1999-01-01

    In order to develop vehicles which have maximum active safety, car manufacturers need information about the so-called force and moment properties of tyres. Vehicle manufacturers, tyre suppliers and automotive research organisations have advanced test equipment to measure the forces between a tyre

  16. Ambulatory measurement of ground reaction force and estimation of ankle and foot dynamics

    NARCIS (Netherlands)

    Schepers, H. Martin; Koopman, Hubertus F.J.M.; Baten, Christian T.M.; Veltink, Petrus H.

    INTRODUCTION Traditionally, human body movement analysis is done in so-called ‘gait laboratories’. In these laboratories, body movement is measured by a camera system using optical markers, the ground reaction force by a force plate fixed in the floor, and the muscle activity by EMG. From the body

  17. Prevention of tick bites: an evaluation of a smartphone app

    OpenAIRE

    Antonise-Kamp, L.; Beaujean, D. J. M. A.; Crutzen, R.; van Steenbergen, J. E.; Ruwaard, D.

    2017-01-01

    Background Lyme borreliosis (LB) is the most common reported tick-borne infection in Europe, and involves transmission of Borrelia by ticks. As long as a vaccine is not available and effective measures for controlling tick populations are insufficient, LB control is focused on preventive measures to avoid tick bites. To inform citizens about the risk of ticks, motivate them to check for tick bites, and encourage them to remove any attached tick as quickly as possible, a mobile app called ‘Tek...

  18. Heridas por Mordedura / Bites Injuries

    Directory of Open Access Journals (Sweden)

    Coturel A

    2015-11-01

    Full Text Available Injuries for animal bites are a common cause of consultation to emergency services. However there are still controversies about some aspects of their treatment. It is not recommended to brush the wound area but to flush the surface with isoosmolar saline. The primary wound closure is justified when improves the cosmetic outcome and has no increase risk of infection. Antibiotic prophylaxis is allways indicated in cats or humans bites. The drug of choice is amoxicillin clavulanate.The tetanus vaccine should be indicated when the patient has not full vaccination scheme and rabies vaccine in cases of suspected or confirmed infected animals.

  19. Venomous bites, stings, and poisoning.

    Science.gov (United States)

    Warrell, David A

    2012-06-01

    This article discusses the epidemiology, prevention, clinical features, first aid and medical treatment of venomous bites by snakes, lizards, and spiders; stings by fish, jellyfish, echinoderms, and insects; and poisoning by fish and molluscs, in all parts of the world. Of these envenoming and poisonings, snake bite causes the greatest burden of human suffering, killing 46,000 people each year in India alone and more than 100,000 worldwide and resulting in physical handicap in many survivors. Specific antidotes (antivenoms/antivenins) are available to treat envenoming by many of these taxa but supply and distribution is inadequate in many tropical developing countries. Copyright © 2012. Published by Elsevier Inc.

  20. White shark ( Carcharodon carcharias )-inflicted bite wounds ...

    African Journals Online (AJOL)

    White shark ( Carcharodon carcharias )-inflicted bite wounds observed on Cape fur seals ( Arctocephalus pusillus pusillus ) at Black Rocks, Algoa Bay, South Africa. ... The low number of bite-inflicted injuries observed suggests that white sharks attack seals infrequently at Black Rocks. Key words: Algoa Bay, bite injuries, ...

  1. 21 CFR 882.5070 - Bite block.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Bite block. 882.5070 Section 882.5070 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Therapeutic Devices § 882.5070 Bite block. (a) Identification. A bite block...

  2. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... for (var c = 0; c How to stop biting your nails Nail biting typically begins in childhood and can continue through ... effects can be more than cosmetic. Repeated nail biting can make the skin around your nails feel ...

  3. Intra-operative measurement of applied forces during anterior scoliosis correction.

    Science.gov (United States)

    Fairhurst, H; Little, J P; Adam, C J

    2016-12-01

    Spinal instrumentation and fusion for the treatment of scoliosis is primarily a mechanical intervention to correct the deformity and halt further progression. While implant-related complications remain a concern, little is known about the magnitudes of the forces applied to the spine during surgery, which may affect post-surgical outcomes. In this study, the compressive forces applied to each spinal segment during anterior instrumentation were measured in a series of patients with Adolescent Idiopathic Scoliosis. A force transducer was designed and retrofit to a routinely used surgical tool, and compressive forces applied to each segment during surgery were measured for 15 scoliosis patients. Cobb angle correction achieved by each force was measured on intra-operative fluoroscope images. Relative changes in orientation of the screw within the vertebra were also measured to detect intra-operative screw plough. Intra-operative forces were measured for a total of 95 spinal segments. The mean applied compressive force was 540N (SD 230N, range 88N-1019N). There was a clear trend for higher forces to be applied at segments toward the apex of the scoliosis. Fluoroscopic evidence of screw plough was detected at 10 segments (10.5%). The magnitude of forces applied during anterior scoliosis correction vary over a broad range. These forces do reach magnitudes capable of causing intra-operative vertebral body screw plough. Surgeons should be aware there is a risk for tissue overload during correction, however the clinical implications of intra-operative screw plough remain unclear. The dataset presented here is valuable for providing realistic input parameters for in silico surgical simulations. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. A new bi-axial cantilever beam design for biomechanics force measurements.

    Science.gov (United States)

    Lin, Huai-Ti; Trimmer, Barry A

    2012-08-31

    The demand for measuring forces exerted by animals during locomotion has increased dramatically as biomechanists strive to understand and implement biomechanical control strategies. In particular, multi-axial force transducers are often required to capture animal limb coordination patterns. Most existing force transducers employ strain gages arranged in a Wheatstone bridge on a cantilever beam. Bi-axial measurements require duplicating this arrangement in the transverse direction. In this paper, we reveal a method to embed a Wheatstone bridge inside another to allow bi-axial measurements without additional strain gages or additional second beams. This hybrid configuration resolves two force components from a single bridge circuit and simplifies fabrication for the simultaneous assessment of normal and transverse loads. This design can be implemented with two-dimensional fabrication techniques and can even be used to modify a common full bridge cantilever force transducer. As a demonstration of the new design, we built a simple beam which achieved bi-axial sensing capability that outperformed a conventional half-bridge-per-axis bi-axial strain gage design. We have used this design to measure the ground reaction forces of a crawling caterpillar and a caterpillar-mimicking soft robot. The simplicity and increased sensitivity of this method could facilitate bi-axial force measurements for experimental biologists. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Measurements of Normal and Friction Forces in a Rolling Process

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens; Wanheim, Tarras

    2004-01-01

    To improve the quality of frictional data and to validate the simulations in rolling, a load transducer for measuring normal and friction stresses in the deformation zone has been developed. The transducer consists of a strain gauge equipped insert embedded in the surface of the roll. The length...... of the insert exceeds the contact length. By analyzing the output from the insert, the friction stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by a lower disturbance of lubricant film and material flow and limited penetration of material...

  6. Measurement of Normal and Friction Forces in a Rolling Process

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens; Wanheim, Tarras

    2004-01-01

    by the fric-tion conditions. To achieve this important informa-tion, measurements of the normal pressure and friction stresses in the deformation zone are re-quested. The direction of the friction stresses is changing during the rolling gap. At the entrance of the de-formation zone, the peripherical velocity...... of the roll is higher than for the incoming material, which causes frictional stresses at the material acting in the rolling direction. At the outlet of the rolling gap, the velocity of the deformed material exceeds the velocity of the roll, generating frictional stresses contrary to the direction of rolling...

  7. Measurements of normal and frictional forces in a rolling process

    DEFF Research Database (Denmark)

    Henningsen, Poul; Arentoft, Mogens; Wanheim, Tarras

    2006-01-01

    of the insert exceeds the contact length. By analysing the output from the insert, the frictional stress and normal pressure in the contact zone can be determined. The new concept differs from existing pin designs by less disturbance of lubricant film and material flow and limited penetration of material......To improve the quality of frictional data and to validate the simulations in rolling, a load transducer for measuring normal and frictional stresses in the deformation zone has been developed. The transducer consists of a strain-gauge-equipped insert embedded in the surface of the roll. The length...

  8. Measuring Relationships: A Model for Evaluating U.S. Air Force Public Affairs Programs

    National Research Council Canada - National Science Library

    Della Vedova, Joseph P

    2005-01-01

    The thesis advanced here is that Air Force Public Affairs should be responsible for managing the organization-public relationship and that the effectiveness of that management can be measured in terms...

  9. Spring constant measurement using a MEMS force and displacement sensor utilizing paralleled piezoresistive cantilevers

    Science.gov (United States)

    Kohyama, Sumihiro; Takahashi, Hidetoshi; Yoshida, Satoru; Onoe, Hiroaki; Hirayama-Shoji, Kayoko; Tsukagoshi, Takuya; Takahata, Tomoyuki; Shimoyama, Isao

    2018-04-01

    This paper reports on a method to measure a spring constant on site using a micro electro mechanical systems (MEMS) force and displacement sensor. The proposed sensor consists of a force-sensing cantilever and a displacement-sensing cantilever. Each cantilever is composed of two beams with a piezoresistor on the sidewall for measuring the in-plane lateral directional force and displacement. The force resolution and displacement resolution of the fabricated sensor were less than 0.8 µN and 0.1 µm, respectively. We measured the spring constants of two types of hydrogel microparticles to demonstrate the effectiveness of the proposed sensor, with values of approximately 4.3 N m-1 and 15.1 N m-1 obtained. The results indicated that the proposed sensor is effective for on-site spring constant measurement.

  10. Epidemiological study of insect bite reactions from Central India

    Directory of Open Access Journals (Sweden)

    Sumit Kar

    2013-01-01

    Full Text Available Introduction: The physical effects of the arthropod bites on human skin receive less attention, especially in the rural areas where the per capita income is less. Ours is a rural-based hospital, the vicinity having more of plants, trees, and forests; we undertook the study to find out the relation of insect bite dermatitis in a rural area. Materials and Methods: The study was carried out in the Dermatology outpatient department of our institute on 100 subjects of insect bite dermatitis who were questioned retrospectively about the sequence of events besides their environmental and living conditions. They were examined thoroughly and the relevant clinical findings were noted, also taking into account the prior treatment taken by them, if any. Results and Conclusions: It was found that insect bite dermatitis has no age or gender preponderance, and the protective factors for the same are use of full sleeve clothes and keeping the doors and windows closed at night. On the contrary, the risk factors are residence in areas of heavy insect infestation, use of perfumes and colognes, warm weather in spring and summer and the lack of protective measures. However, there was no direct association of atopy with increased risk of developing insect bite dermatitis.

  11. Kissing Bug ( spp. Intrusion into Homes: Troublesome Bites and Domiciliation

    Directory of Open Access Journals (Sweden)

    Stephen A. Klotz

    2016-01-01

    Full Text Available Kissing bugs ( Triatoma spp. frequently enter homes and bite human and pet occupants. Bites may lead to severe allergic reactions and, in some cases, death. Kissing bugs are also vectors of Trypanosoma cruzi , the cause of Chagas disease. In general, modern houses in the United States are not conducive to domiciliation of kissing bugs (bugs living out their entire life within the home with the presence of eggs, nymphs, adults, and exuviae. Construction features such as concrete foundations, solid walls and ceilings, window screens, tight thresholds for doors and windows, and other measures impede bug entry into homes, and air conditioning reduces the need for open doors and windows. Where Chagas disease is endemic in Mexico and Central and South America, homes often have thatch roofs, adobe walls, and open doors and windows. We investigated numerous instances of kissing bug intrusions into homes in Southern Arizona, California, and Louisiana and documented the reactions to kissing bug bites. Our work confirms the importance of modern home construction in limiting kissing bug intrusions. Older homes, especially those lacking modern screening, caulking, and weather stripping to reduce air leakage, may be subject to kissing bug intrusions and domiciliation. We describe a community in Southern Arizona where domiciliation of homes by Triatoma recurva is common. We also provide recent data regarding kissing bug bites and allergic reactions to the bites.

  12. Subsurface measurement of nanostructures on GaAs by electrostatic force microscopy

    International Nuclear Information System (INIS)

    Yamada, Fumihiko; Kamiya, Itaru

    2013-01-01

    The size of surface buried oxide nanostructures are measured by electrostatic force microscopy (EFM). In contrast to atomic force microscopy that cannot probe subsurface structures and thickness, we show that EFM data include information about the thickness of individual nanostructures, consequently allowing us to determine the thickness of buried nanostructures on semiconductor substrates. We further show that this measurement can be performed simultaneously with AFM using EFM modulation spectroscopy.

  13. Measurement of wisdom forging force using piezoelectric materials

    Directory of Open Access Journals (Sweden)

    Hsia Shao-Yi

    2017-01-01

    Full Text Available Aiming at forging machines for bolts and nuts with up to 61% market share, adding piezoelectric sensing units to the mold forging is discussed in this study. In the research process, it attempts to develop a sensing element with low cost, practicable limited space, acceptable performance stability, and real-time measurement of forging load by a five-stage forming system for special nuts matched with the theory of plastic forming, the CAD/CAE design and numerical analysis, and the installation of a piezoelectric unit. It aims to assist fastener businesses in the intelligentization, networking, and systemization of machines and further integrate into the Internet service manufacturing system to enhance the overall competitiveness of fastener industry.

  14. Oncology Section EDGE Task Force on Urogenital Cancer: A Systematic Review of Clinical Measures for Incontinence.

    Science.gov (United States)

    Jeffrey, Alicia; Harrington, Shana E; Hill, Alexandra; Roscow, Amanda; Alappattu, Meryl

    2017-07-01

    Compared to the general population, women and men with urogenital and colorectal cancer experience higher rates of urinary and fecal incontinence. Although a variety of measures exist to assess these areas, currently, there are no guidelines recommending which outcomes rehabilitation professionals should administer to examine these impairments in those with cancer. To identify outcome measures for assessing urinary and fecal incontinence and evaluate their psychometric data and applicability to the cancer population. Multiple electronic databases (CINAHL, Medline, PsycInfo) were reviewed using specific search terms to locate articles that identify outcome measures assessing urinary and fecal incontinence. As part of a larger effort to identify outcome measures for both incontinence and sexual dysfunction, 1118 articles were initially identified, 228 articles were reviewed, and 37 outcome measures were selected for analysis, 13 of which were related to urinary and fecal incontinence. Each incontinence outcome measure was independently reviewed and rated by two reviewers using the Cancer EDGE Task Force Outcome Measure Rating Form. Any discrepancies between reviewers were discussed and an overall recommendation for each outcome measure was made using the 4-point Cancer EDGE Task Force Rating Scale. The Task Force was able to highly recommend 1 measure addressing urinary incontinence (American Urological Association Symptom Index) and 2 measures assessing both urinary and fecal incontinence (Pelvic Floor Distress Inventory - Short Form, Pelvic Floor Impact Questionnaire - Short Form). The Task Force also recommended two measures of urinary incontinence that demonstrated strong psychometric properties, but had not yet been evaluated in the cancer population (Incontinence Quality of Life Questionnaire, International Consultation on Incontinence Questionnaire - Short Form). The Task Force was unable to recommend any measures that solely addressed fecal incontinence. Five

  15. Fabrication of oriented crystals as force measurement tips via focused ion beam and microlithography methods

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Zhigang [School of Science, North University of China, Shanxi 030051 China; Chun, Jaehun [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, WA USA; Chatterjee, Sayandev [Energy and Environment Directorate, Pacific Northwest National Laboratory, WA USA; Li, Dongsheng [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, WA USA

    2017-11-09

    Detailed knowledge of the forces between nanocrystals is very crucial for understanding many generic (e.g., random aggregation/assembly and rheology) and specific (e.g., oriented attachment) phenomena at macroscopic length scales, especially considering the additional complexities involved in nanocrystals such as crystal orientation and corresponding orientation-dependent physicochemical properties. Because there are a limited number of methods to directly measure the forces, little is known about the forces that drive the various emergent phenomena. Here we report on two methods of preparing crystals as force measurement tips used in an atomic force microscope (AFM): the focused ion beam method and microlithography method. The desired crystals are fabricated using these two methods and are fixed to the AFM probe using platinum deposition, ultraviolet epoxy, or resin, which allows for the orientation-dependent force measurements. These two methods can be used to attach virtually any solid particles (from the size of a few hundreds of nanometers to millimeters). We demonstrate the force measurements between aqueous media under different conditions such as pH.

  16. Digital design and fabrication of simulation model for measuring orthodontic force.

    Science.gov (United States)

    Liu, Yun-Feng; Zhang, Peng-Yuan; Zhang, Qiao-Fang; Zhang, Jian-Xing; Chen, Jie

    2014-01-01

    Three dimensional (3D) forces are the key factors for determining movement of teeth during orthodontic treatment. Designing precise forces and torques on tooth before treatment can result accurate tooth movements, but it is too difficult to realize. In orthodontic biomechanical systems, the periodontal tissues, including bones, teeth, and periodontal ligaments (PDL), are affected by braces, and measuring the forces applied on the teeth by braces should be based on a simulated model composed of these three types of tissues. This study explores the design and fabrication of a simulated oral model for 3D orthodontic force measurements. Based on medical image processing, tissue reconstruction, 3D printing, and PDL simulation and testing, a model for measuring force was designed and fabricated, which can potentially be used for force prediction, design of treatment plans, and precise clinical operation. The experiment illustrated that bi-component silicones with 2:8 ratios had similar mechanical properties to PDL, and with a positioning guide, the teeth were assembled in the mandible sockets accurately, and so a customized oral model for 3D orthodontic force measurement was created.

  17. Sexual dimorphism in bite performance drives morphological variation in chameleons.

    Directory of Open Access Journals (Sweden)

    Jessica M da Silva

    Full Text Available Phenotypic performance in different environments is central to understanding the evolutionary and ecological processes that drive adaptive divergence and, ultimately, speciation. Because habitat structure can affect an animal's foraging behaviour, anti-predator defences, and communication behaviour, it can influence both natural and sexual selection pressures. These selective pressures, in turn, act upon morphological traits to maximize an animal's performance. For performance traits involved in both social and ecological activities, such as bite force, natural and sexual selection often interact in complex ways, providing an opportunity to understand the adaptive significance of morphological variation with respect to habitat. Dwarf chameleons within the Bradypodion melanocephalum-Bradypodion thamnobates species complex have multiple phenotypic forms, each with a specific head morphology that could reflect its use of either open- or closed-canopy habitats. To determine whether these morphological differences represent adaptations to their habitats, we tested for differences in both absolute and relative bite performance. Only absolute differences were found between forms, with the closed-canopy forms biting harder than their open-canopy counterparts. In contrast, sexual dimorphism was found for both absolute and relative bite force, but the relative differences were limited to the closed-canopy forms. These results indicate that both natural and sexual selection are acting within both habitat types, but to varying degrees. Sexual selection seems to be the predominant force within the closed-canopy habitats, which are more protected from aerial predators, enabling chameleons to invest more in ornamentation for communication. In contrast, natural selection is likely to be the predominant force in the open-canopy habitats, inhibiting the development of conspicuous secondary sexual characteristics and, ultimately, enforcing their overall diminutive

  18. Design and testing of an innovative measurement device for tyre-road contact forces

    Science.gov (United States)

    Cheli, F.; Braghin, F.; Brusarosco, M.; Mancosu, F.; Sabbioni, E.

    2011-08-01

    The measurement of tyre-road contact forces is the first step towards the development of new control systems for improving vehicle safety and performances. Tyre-road contact forces measurement systems are very expensive and significantly modify the unsprung masses of the vehicle as well as the rotational inertia of the tyres. Thus, vehicle dynamics results are significantly affected. As a consequence, the measured contact forces do not correspond to the contact forces under real working conditions. A new low-cost tyre-road contact forces measurement system is proposed in this paper that can be applied to passenger cars. Its working principle is based on the measurement of three deformations of the wheel rim through strain gauges. The tyre-rim assembly is thus turned into a sensor for tyre-road contact forces. The influence of the strain gauges position onto the measurement results has been assessed through finite element simulations and experimental tests. It has been proven that, for a large variety of rims, the strain gauge position that leads to high signal-to-noise ratios is almost the same. A dynamic calibration procedure has been developed in order to allow the reconstruction of contact force and torque components once per wheel turn. The capability of the developed device to correctly estimate tyre-road contact forces has been assessed, in a first stage, through indoor laboratory experimental test on an MTS Flat-Trac ® testing machine. Results show that the implemented measuring system allows to reconstruct contact forces once per wheel turn with a precision that is comparable to that of existing high-cost measurement systems. Subsequently, outdoor tests with a vehicle having all four wheels equipped with the developed measuring device have also been performed. Reliability of the measurements provided by the developed sensor has been assessed by comparing the global measured longitudinal/lateral forces and the product of the measured longitudinal

  19. Mosquito Bite Prevention For Travelers

    Science.gov (United States)

    ... bites. Here’s how: Keep mosquitoes out of your hotel room or lodging Š Choose a hotel or lodging with air conditioning or screens on ... percentages of active ingredient provide longer protection Some brand name examples* (Insect repellents may be sold under ...

  20. A comparison of bite size and BMI in a cafeteria setting.

    Science.gov (United States)

    Mattfeld, Ryan S; Muth, Eric R; Hoover, Adam

    2017-11-01

    Our study investigated the relationship between BMI and bite size in a cafeteria setting. Two hundred and seventy one participants consumed one meal each. Participants were free to select any food provided by the cafeteria and could return for additional food as desired. Bite weights were measured with a table embedded scale. Data were analyzed with ANOVAs, regressions, Kolmogorov-Smirnov tests, and a repeated measures general linear model for quartile analysis. Obese participants were found to take larger bites than both normal (p=0.002) and overweight participants (p=0.017). Average bite size increased by 0.20g per point increase in BMI. Food bites and drink bites were analyzed individually, showing 0.11g/BMI and 0.23g/BMI slopes, respectively. Quartiles of bites were also analyzed, and a significant interaction was found between normal and obese participants (p=0.034) such that the lower two quartiles were similar, but the upper two quartiles showed an increase in bite size for obese participants. The source of these effects could be the result of a combination of several uncontrolled factors. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Accuracy of force and center of pressure measures of the Wii Balance Board.

    Science.gov (United States)

    Bartlett, Harrison L; Ting, Lena H; Bingham, Jeffrey T

    2014-01-01

    The Nintendo Wii Balance Board (WBB) is increasingly used as an inexpensive force plate for assessment of postural control; however, no documentation of force and COP accuracy and reliability is publicly available. Therefore, we performed a standard measurement uncertainty analysis on 3 lightly and 6 heavily used WBBs to provide future users with information about the repeatability and accuracy of the WBB force and COP measurements. Across WBBs, we found the total uncertainty of force measurements to be within ± 9.1N, and of COP location within ± 4.1mm. However, repeatability of a single measurement within a board was better (4.5 N, 1.5mm), suggesting that the WBB is best used for relative measures using the same device, rather than absolute measurement across devices. Internally stored calibration values were comparable to those determined experimentally. Further, heavy wear did not significantly degrade performance. In combination with prior evaluation of WBB performance and published standards for measuring human balance, our study provides necessary information to evaluate the use of the WBB for analysis of human balance control. We suggest the WBB may be useful for low-resolution measurements, but should not be considered as a replacement for laboratory-grade force plates. Published by Elsevier B.V.

  2. Experimental measurements of hydrodynamic radial forces and stiffness matrices for a centrifugal pump-impeller

    Science.gov (United States)

    Chamieh, D. S.; Acosta, A. J.; Brennen, C. E.; Caughey, T. K.

    1985-01-01

    Measurements of the steady-state hydrodynamic forces on a centrifugal pump impeller are presented as a function of position within two geometrically different volutes. These correspond to the forces experienced by the impeller at zero whirl frequency. The hydrodynamic force matrices derived from these measurements exhibit both diagonal and off-diagonal terms of substantial magnitude. These terms are of the form which would tend to excite a whirl motion in a rotordynamic analysis of the pump; this may be the cause of 'rough running' reported in many pumps. Static pressure measurements in the impeller discharge flow show that the hydrodynamic force on the impeller contains a substantial component due to the nonisotropy of the net momentum flux leaving the impeller. A similar breakdown of the contributions to the stiffness matrices reveals that the major component of these matrices results from the nonisotropy of the momentum flux.

  3. K-9 Police Dog Bite

    Directory of Open Access Journals (Sweden)

    Vy Han

    2017-01-01

    Full Text Available History of present illness: A 30-year-old male who was brought into the emergency department (ED by police officers after being bitten in the right lower extremity by a police German Shepard after attempting to flee authorities on foot. The patient stated that the dog immediately bit down on his right calf and proceeded to violently shake its head side to side without releasing its grip until police manually pulled the dog off of him. Upon arrival to the ED, he was tachycardic in the 120’s, complaining of severe, throbbing, sharp pain in the right lower extremity, and was neurovascular intact on exam. Significant findings: The photograph is of the anterior compartment of the right lower leg demonstrating multiple deep lacerations with exposed and torn muscle. X-ray showed no foreign body. Discussion: Police dog bites should be treated more cautiously than typical dog bites because these highly-trained dogs are generally larger breeds which are taught to subdue suspects with a bite-and-hold technique rather than bite and release. This can lead to extensive crush injuries, fractures, large caliber lacerations with associated muscle tissue injury and/or severe neurovascular compromise.1 Hence, police dog bites often require provocative diagnostic testing, specialist consultation for possible operative repair, and aggressive irrigation and ultimately admission for intravenous antibiotics.1 This patient’s wound was aggressively irrigated and evaluated by plastic surgery in the ED. He was ultimately admitted for intravenous antibiotics, pain control, wound care, and healing by secondary intention.

  4. Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope

    DEFF Research Database (Denmark)

    Jensen, Carsten P.

    Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope......Calibrated atomic force microscope measurements of vickers hardness indentations and tip production and characterisation for scanning tunelling microscope...

  5. An in-fiber Bragg grating sensor for contact force and stress measurements in articular joints

    International Nuclear Information System (INIS)

    Dennison, Christopher R; Wild, Peter M; Wilson, David R; Gilbart, Michael K

    2010-01-01

    We present an in-fiber Bragg grating-based sensor (240 µm diameter) for contact force/stress measurements in articular joints. The contact force sensor and another Bragg grating-based pressure sensor (400 µm diameter) are used to conduct the first simultaneous measurements of contact force/stress and fluid pressure in intact cadaveric human hips. The contact force/stress sensor addresses limitations associated with stress-sensitive films, the current standard tools for contact measurements in joints, including cartilage modulus-dependent sensitivity of films and the necessity to remove biomechanically relevant anatomy to implant the films. Because stress-sensitive films require removal of anatomy, it has been impossible to validate the mechanical rationale underlying preventive or corrective surgeries, which repair these anatomies, by conducting simultaneous stress and pressure measurements in intact hips. Methods are presented to insert the Bragg grating-based sensors into the joint, while relevant anatomy is left largely intact. Sensor performance is predicted using numerical models and the predicted sensitivity is verified through experimental calibrations. Contact force/stress and pressure measurements in cadaveric joints exhibited repeatability. With further validation, the Bragg grating-based sensors could be used to study the currently unknown relationships between contact forces and pressures in both healthy and degenerated joints

  6. QCM-based rupture force measurement as a tool to study DNA dehybridization and duplex stability.

    Science.gov (United States)

    Dultsev, Fedor N; Kolosovsky, Eugeny A; Lomzov, Alexander A; Pyshnyi, Dmitrii V

    2017-02-01

    The stability of double-stranded DNA (dsDNA) was assessed on the basis of unwinding force measurement. Unwinding force was measured directly with a quartz crystal microbalance (QCM). The amplitude of its surface oscillations was controlled by supplying variable alternate voltage. Under smoothly increasing amplitude of QCM surface oscillations, dsDNA fixed on QCM surface through one of its ends got unwound. This procedure allows reliable measurement of rupture force as small as 5-10 pN. It was demonstrated that oscillations of the surface, with dsDNA bound through one of its ends to this surface, at a frequency of 14 MHz, cause helix unwinding to form two complementary parts due to viscous forces of the liquid medium. Unwinding starts at the upper end. This was proven using oligonucleotide duplexes containing mismatches in different positions. For duplexes containing complementary 20 base pairs, the helix unwinding force is equal to 30-40 pN, which is in agreement with the data obtained by means of atomic-force microscopy (AFM) for the case of unzipping mode. Graphical Abstract Rupture force depending on mismatch position in dsDNA.

  7. Prestress Force Identification for Externally Prestressed Concrete Beam Based on Frequency Equation and Measured Frequencies

    Directory of Open Access Journals (Sweden)

    Luning Shi

    2014-01-01

    Full Text Available A prestress force identification method for externally prestressed concrete uniform beam based on the frequency equation and the measured frequencies is developed. For the purpose of the prestress force identification accuracy, we first look for the appropriate method to solve the free vibration equation of externally prestressed concrete beam and then combine the measured frequencies with frequency equation to identify the prestress force. To obtain the exact solution of the free vibration equation of multispan externally prestressed concrete beam, an analytical model of externally prestressed concrete beam is set up based on the Bernoulli-Euler beam theory and the function relation between prestress variation and vibration displacement is built. The multispan externally prestressed concrete beam is taken as the multiple single-span beams which must meet the bending moment and rotation angle boundary conditions, the free vibration equation is solved using sublevel simultaneous method and the semi-analytical solution of the free vibration equation which considered the influence of prestress on section rigidity and beam length is obtained. Taking simply supported concrete beam and two-span concrete beam with external tendons as examples, frequency function curves are obtained with the measured frequencies into it and the prestress force can be identified using the abscissa of the crosspoint of frequency functions. Identification value of the prestress force is in good agreement with the test results. The method can accurately identify prestress force of externally prestressed concrete beam and trace the trend of effective prestress force.

  8. Predicting Diaphyseal Cortical Bone Status Using Measures of Muscle Force Capacity.

    Science.gov (United States)

    Higgins, Simon; Sokolowski, Chester M; Vishwanathan, Megha; Anderson, Jessica G; Schmidt, Michael D; Lewis, Richard D; Evans, Ellen M

    2018-02-16

    Muscle cross sectional area (MCSA) is often used as a surrogate for the forces applied to bones during physical activity. Though MCSA is a strong predictor of cortical bone status, its use makes assumptions about the relationship between muscle size and force that are inaccurate. Furthermore, to measure MCSA and other muscle force surrogates typically requires expensive and/or radiative laboratory equipment. Thus, this study aimed to determine whether clinical lab- and field-based methodologies for measuring muscular force capacity accounted for similar variance in diaphyseal cortical bone status as a commonly used muscular force surrogate; MCSA, at the mid-tibia in young men and women. Healthy young adults (n = 142, 19.7 ± 0.7 yo, 52.8% female) were assessed via peripheral quantitative computed tomography at the mid-tibia for cortical bone status and MCSA. Muscle force capacity was measured via Biodex dynamometer, Nottingham leg extensor power rig, and Vertec vertical jump. Regression analysis compared the independent variance predicted by each muscle force measure to that of MCSA, accounting for relevant confounders. MCSA, knee extension peak torque, and peak anaerobic power from vertical jump were independent predictors of select cortical structural outcomes (cortical thickness and area, periosteal and endosteal circumference, and estimated strength) accounting for up to 78.4% of the variance explained (all p<.05). However, cortical volumetric bone mineral density was unrelated to any measure or surrogate of muscle force capacity. MCSA is a strong independent predictor of cortical bone structure; however, both lab- and field-based measures of peak torque and/or peak anaerobic power are promising alternatives, explaining similar and sometimes greater variance than MCSA.

  9. Modeling the effect of probe force on length measurements on polymer parts

    DEFF Research Database (Denmark)

    Mohammadi, Ali; Sonne, Mads Rostgaard; Dalla Costa, Giuseppe

    2016-01-01

    Measurement uncertainty at micrometer level is in the future going to be very common in dimensional measurements on polymer parts. Accurate dimensional measurement of polymer parts is becoming a key and common practice in the industry, especially when micrometer tolerances are required. When...... numerically. Both analytical and numerical approaches were compared with the experimental results. The results showed that the numerical model was able to predict the deformation of the polymer part due to different probe forces. Furthermore it was shown, that the probe force should be taking into account...... when measurement with a few micrometer accuracy should be performed on thin walled polymer parts....

  10. The use of piezoelectric bimorph transducers to measure forces in colloidal systems

    International Nuclear Information System (INIS)

    Stewart, A.M.

    1996-01-01

    The Surface Force Apparatus developed in this Department has proved useful for the measurement of colloidal forces between transparent surfaces in liquids and gases at surface separations of 1 nm up to 500 nm. The distance between the surfaces is measured by the interferometry of white light, and the force is measured from the movement of one of the surfaces that is attached to a cantilever spring which deflects under the influence of the force. In the present work an analysis is made of the effect of the errors introduced at a longer time scale by bimorph drift and decay upon accuracy of measurement. For direct measurements the errors will be small provided that the time constant of the bimorph, given by the product of its capacitance and amplifier input impedance, is much larger than the total time of measurement. With the force-feedback technique the errors will be negligible provided that, in addition the integrator time constant is much smaller than the bimorph time constant, a condition easily satisfied. In is important to use an amplifier with a very high input impedance to buffer bimorphs used for this type of measurement

  11. Transient Response of an Impacted Beam and Indirect Impact Force Identification Using Strain Measurements

    Directory of Open Access Journals (Sweden)

    Hyungsoon Park

    1994-01-01

    Full Text Available The impulse response functions (force-strain relations for Euler–Bernoulli and Timoshenko beams are considered. The response of a beam to a transverse impact force, including reflection at the boundary, is obtained with the convolution approach using the impulse response function obtained by a Laplace transform and a numerical scheme. Using this relation, the impact force history is determined in the time domain and results are compared with those of Hertz's contact law. In the case of an arbitrary impact, the location of the impact force and the time history of the impact force can be found. In order to verify the proposed algorithm, measurements were taken using an impact hammer and a drop test of a steel ball. These results are compared with simulated ones.

  12. Laboratory measurement verification of laser hazard analysis for miles weapon simulators used in force on force exercises.

    Energy Technology Data Exchange (ETDEWEB)

    Augustoni, Arnold L.

    2006-08-01

    Due to the change in the batteries used with the Small Arm Laser Transmitters (SALT) from 3-volts dc to 3.6-volts dc and changes to SNL MILES operating conditions, the associated laser hazards of these units required re-evaluation to ensure that the hazard classification of the laser emitters had not changed as well. The output laser emissions of the SNL MILES, weapon simulators and empire guns, used in Force-On-Force (FOF) training exercises, was measured in accordance to the ANSI Standard Z136.4-2005, ''Recommended Practice for Laser Safety Measurements for Hazard Evaluation''. The laser hazard class was evaluated in accordance with the ANSI Standard Z136.1-2000, ''Safe Use of Lasers'', using ''worst'' case conditions associated with these MILES units. Laser safety assessment was conducted in accordance with the ANSI Standard Z136.6-2005, ''Safe Use of Lasers Outdoors''. The laser hazard evaluation of these MILES laser emitters was compared to and supersedes SAND Report SAND2002-0246, ''Laser Safety Evaluation of the MILES and Mini MILES Laser Emitting Components'', which used ''actual'' operating conditions of the laser emitters at the time of its issuance.

  13. Development and testing of an integrated smart tool holder for four-component cutting force measurement

    Science.gov (United States)

    Xie, Zhengyou; Lu, Yong; Li, Jianguang

    2017-09-01

    Cutting force measurement is a significant requirement for monitoring and controlling the machining processes. Hence, various methods of measuring the cutting force have been proposed by many researchers. In this study, an innovative integrated smart tool holder system based on capacitive sensors is designed, constructed and tested, which is capable of measuring triaxial cutting force and a torque simultaneously in a wireless environment system. A standard commercial tool holder is modified to make itself be the force sensing element that has advantages of simple structure and easy machining. Deformable beams are created in the tool holder, and the tiny deformations of which used to calculate the four-component cutting force are detected by six high precision capacitive sensors. All the sensors and other electronics, like data acquisition and transmitting unit, and wireless power unit, are incorporated into the tool holder as a whole system. The device is intended to be used in a rotating spindle such as in milling and drilling processes. Eventually, the static and dynamic characteristics of the smart tool holder have been determined by a series of tests. Cutting tests have also been carried out and the results show it is stable and practical to measure the cutting force in milling and drilling processes.

  14. Pushing nanoparticles with light — A femtonewton resolved measurement of optical scattering forces

    Directory of Open Access Journals (Sweden)

    C. Zensen

    2016-05-01

    Full Text Available Optomechanical manipulation of plasmonic nanoparticles is an area of current interest, both fundamental and applied. However, no experimental method is available to determine the forward-directed scattering force that dominates for incident light of a wavelength close to the plasmon resonance. Here, we demonstrate how the scattering force acting on a single gold nanoparticle in solution can be measured. An optically trapped 80 nm particle was repetitively pushed from the side with laser light resonant to the particle plasmon frequency. A lock-in analysis of the particle movement provides a measured value for the scattering force. We obtain a resolution of less than 3 femtonewtons which is an order of magnitude smaller than any measurement of switchable forces performed on nanoparticles in solution with single beam optical tweezers to date. We compared the results of the force measurement with Mie simulations of the optical scattering force on a gold nanoparticle and found good agreement between experiment and theory within a few fN.

  15. A High Performance Sensor for Triaxial Cutting Force Measurement in Turning

    Directory of Open Access Journals (Sweden)

    You Zhao

    2015-04-01

    Full Text Available This paper presents a high performance triaxial cutting force sensor with excellent accuracy, favorable natural frequency and acceptable cross-interference for high speed turning process. Octagonal ring is selected as sensitive element of the designed sensor, which is drawn inspiration from ring theory. A novel structure of two mutual-perpendicular octagonal rings is proposed and three Wheatstone full bridge circuits are specially organized in order to obtain triaxial cutting force components and restrain cross-interference. Firstly, the newly developed sensor is tested in static calibration; test results indicate that the sensor possesses outstanding accuracy in the range of 0.38%–0.83%. Secondly, impacting modal tests are conducted to identify the natural frequencies of the sensor in triaxial directions (i.e., 1147 Hz, 1122 Hz and 2035 Hz, which implies that the devised sensor can be used for cutting force measurement in a high speed lathe when the spindle speed does not exceed 17,205 rev/min in continuous cutting condition. Finally, an application of the sensor in turning process is operated to show its performance for real-time cutting force measurement; the measured cutting forces demonstrate a good accordance with the variation of cutting parameters. Thus, the developed sensor possesses perfect properties and it gains great potential for real-time cutting force measurement in turning.

  16. Skeletal and Dentoalveolar Cephalometric Features of Anterior Open Bite among Yemeni Adults.

    Science.gov (United States)

    Daer, Ammar Abdulkareem; Abuaffan, Amal Hussein

    2016-01-01

    Objective. The aim of this study is to determine the cephalometric features for a sample of Yemeni adults with anterior open bite. Material and Methods. Lateral cephalometric radiographs were taken for 65 Yemeni university students (46 males and 19 females), 18-25 years old, with clinical anterior open bite (vertical overbite ≤ 0 mm) and no previous orthodontic treatment. The radiographs were manually traced; twelve angular, five linear measurements, and facial index were assessed, analyzed statistically, and compared to 194 Yemeni norms (89 males and 105 females) as well as cephalometric features of open bite subjects in previous studies. Results. Statistically significant differences were observed in skeletal and dental cephalometric values of Yemeni patients with anterior open bite when compared to Yemeni norms; mainly in the anteroposterior relation, the open bite individuals had higher significant value in SNA, SNB, and SNPg angles. In addition, a higher statistical significant difference was recorded in all variables of vertical relation when compared with norms. In contrast, NL-NSL angle revealed higher value among normal individuals. Dental variables among open bite individuals showed a greater degree of dental proclination, higher statistically significant value in [Formula: see text]-NA°, [Formula: see text]-NA mm and I-NB mm, and a lower significant value in U1-L1 in open bite group. Conclusion. Open bite Yemeni individual's skeletal and dentoalveolar variables significantly differ from Yemeni norms in the extent of the anteroposterior, vertical developmental pattern and dental relations.

  17. Human and other mammalian bite injuries of the hand: evaluation and management.

    Science.gov (United States)

    Kennedy, Stephen A; Stoll, Laura E; Lauder, Alexander S

    2015-01-01

    The hand is the most common site for bite injuries. Because of specific characteristics of hand anatomy, bite mechanics, and organisms found in human and animal saliva, even small wounds can lead to aggressive infections. Failure to recognize and treat hand bites can result in significant morbidity. Human and animal bites most commonly lead to polymicrobial bacterial infections with a mixture of aerobic and anaerobic organisms. Pasteurella species are commonly found in dog and cat bite wounds, and Eikenella is characteristic of human wounds. Staphylococcus, Streptococcus, and anaerobic bacterial species are common to all mammals. Although public health measures in developed countries have been highly effective at reducing rabies transmission, dog bites remain the most common source of rabies infection worldwide. Human bites can transmit HIV, hepatitis B, or hepatitis C, especially when contaminated blood is exposed to an open wound. Appropriate management of any mammal bite requires recognition, early wound cleansing, evaluation of injured structures, and infection prophylaxis. Structural repair is performed as indicated by the severity and contamination of the injury, and wounds may require delayed closure. Wound infections typically require débridement, empiric antibiotics, and delayed repair or reconstruction. Copyright 2014 by the American Academy of Orthopaedic Surgeons.

  18. Interaction force measurement between E. coli cells and nanoparticles immobilized surfaces by using AFM.

    Science.gov (United States)

    Zhang, Wen; Stack, Andrew G; Chen, Yongsheng

    2011-02-01

    To better understand environmental behaviors of nanoparticles (NPs), we used the atomic force microscopy (AFM) to measure interaction forces between E. coli cells and NPs immobilized on surfaces in an aqueous environment. The results showed that adhesion force strength was significantly influenced by particle size for both hematite (α-Fe(2)O(3)) and corundum (α-Al(2)O(3)) NPs whereas the effect on the repulsive force was not observed. The adhesion force decreased from 6.3±0.7nN to 0.8±0.4nN as hematite NPs increased from 26nm to 98nm in diameter. Corundum NPs exhibited a similar dependence of adhesion force on particle size. The Johnson-Kendall-Roberts (JKR) model was employed to estimate the contact area between E. coli cells and NPs, and based on the JKR model a new model that considers local effective contact area was developed. The prediction of the new model matched the size dependence of adhesion force in experimental results. Size effects on adhesion forces may originate from the difference in local effective contact areas as supported by our model. These findings provide fundamental information for interpreting the environmental behaviors and biological interactions of NPs, which barely have been addressed. Copyright © 2010 Elsevier B.V. All rights reserved.

  19. Identification of impact force acting on composite laminated plates using the radiated sound measured with microphones

    Science.gov (United States)

    Atobe, Satoshi; Nonami, Shunsuke; Hu, Ning; Fukunaga, Hisao

    2017-09-01

    Foreign object impact events are serious threats to composite laminates because impact damage leads to significant degradation of the mechanical properties of the structure. Identification of the location and force history of the impact that was applied to the structure can provide useful information for assessing the structural integrity. This study proposes a method for identifying impact forces acting on CFRP (carbon fiber reinforced plastic) laminated plates on the basis of the sound radiated from the impacted structure. Identification of the impact location and force history is performed using the sound pressure measured with microphones. To devise a method for identifying the impact location from the difference in the arrival times of the sound wave detected with the microphones, the propagation path of the sound wave from the impacted point to the sensor is examined. For the identification of the force history, an experimentally constructed transfer matrix is employed to relate the force history to the corresponding sound pressure. To verify the validity of the proposed method, impact tests are conducted by using a CFRP cross-ply laminate as the specimen, and an impulse hammer as the impactor. The experimental results confirm the validity of the present method for identifying the impact location from the arrival time of the sound wave detected with the microphones. Moreover, the results of force history identification show the feasibility of identifying the force history accurately from the measured sound pressure using the experimental transfer matrix.

  20. Soft colloidal probes for AFM force measurements between water droplets in oil

    KAUST Repository

    Vakarelski, Ivan Uriev

    2014-11-01

    Here we introduce an extension of the atomic force microscopy (AFM) colloidal probe technique, as a simple and reliable experimental approach to measure the interaction forces between small water droplets (~80-160. μm) dispersed in oil. Small water droplets are formed by capillary breakup of a microscale water jet in air, which is forced out of a fine capillary nozzle, and deposited on a superhydrophobic substrate immersed in tetradecane oil medium. In these conditions the water droplets are very loosely attached to the superhydrophobic substrate and are easily picked up with a hydrophobic AFM cantilever to form a soft colloidal probe. Sample force measurements are conducted to demonstrate the capability of the technique.

  1. High force measurement sensitivity with fiber Bragg gratings fabricated in uniform-waist fiber tapers

    International Nuclear Information System (INIS)

    Wieduwilt, Torsten; Brückner, Sven; Bartelt, Hartmut

    2011-01-01

    Fiber Bragg gratings inscribed in the waist of tapered photosensitive fibers offer specific attractive properties for sensing applications. A small-diameter fiber reduces structural influences for imbedded fiber sensing elements. In the case of application as a force-sensing element for tensile forces, sensitivity scales inversely with the fiber cross-sectional area. It is therefore possible to increase force sensitivity by several orders of magnitude compared to Bragg grating sensors in conventionally sized fibers. Special requirements for such Bragg grating arrangements are discussed and experimental measurements for different fiber taper diameters down to 4 µm are presented

  2. Aerodynamics of Dragonfly in Forward Flight: Force measurements and PIV results

    Science.gov (United States)

    Hu, Zheng; Deng, Xinyan

    2009-11-01

    We used a pair of dynamically scaled robotic dragonfly model wings to investigate the aerodynamic effects of wing-wing interaction in dragonflies. We follow the wing kinematics of real dragonflies in forward flight, while systematically varied the phase difference between the forewing and hindwing. Instantaneous aerodynamic forces and torques were measured on both wings, while flow visualization and PIV results were obtained. The results show that, in forward flight, wing-wing interaction always enhances the aerodynamic forces on the forewing through an upwash brought by the hindwing, while reduces the forces on the hindwing through a downwash brought by the forewing.

  3. Early treatment of anterior open bite: Comparison of the vertical and horizontal morphological changes induced by magnetic bite-blocks and adjusted rapid molar intruders.

    Science.gov (United States)

    Albogha, Mhd Hassan; Takahashi, Ichiro; Sawan, Mhd Naser

    2015-01-01

    This prospective clinical study aims to determine the differences between two treatment modalities for anterior open bite in growing patients. The treatment modalities involved the use of magnetic bite-blocks (MBBs) or rapid molar intruders (RMIs) applied with posterior bite-blocks. Fifteen consecutive patients with a mean age of 11.2 (standard deviation [SD] = 1.6) years and a mean open bite of -3.9 mm were treated with MBBs. Another 15 consecutive patients with a mean age of 10.9 (SD = 1.8) years and a mean open bite of -3.8 mm were treated with RMIs applied on bite-blocks. Cephalometric radiographs were obtained before (T1) and immediately after appliance removal (T2). The treatments lasted four months, during which the appliances were cemented to the teeth. The morphological changes were measured in each group and compared using logistic regression analysis. The MBB group exhibited significantly greater decreases in SNA angle, ANB angle, overjet, and maxillary incisor angle (p open bites and maxillary incisor protrusions.

  4. A Hair Ribbon Deflection Model for Low-intrusiveness Measurement of Bow Force in Violin Performance

    OpenAIRE

    Marchini, Marco; Papiotis, Panos; Pérez, Alfonso; Maestre, Esteban

    2011-01-01

    This paper introduces and evaluates a novel methodologyfor the estimation of bow pressing force in violin performance, aiming at a reduced intrusiveness while maintaininghigh accuracy. The technique is based on using a simplifiedphysical model of the hair ribbon deflection, and feeding thismodel solely with position and orientation measurements ofthe bow and violin spatial coordinates. The physical modelis both calibrated and evaluated using real force data acquired by means of a load cell.

  5. Extended Measurements of Aerodynamic Stability and Limb Dislodgement Forces with the ACES-II Ejection Seat

    Science.gov (United States)

    1975-07-01

    HENNfl^ E. VON GIERKE ’ Director ;*■ Diodynamics and Bionics Division Aerospace Medical Research Laboratory <r U~ /ECcS^’O« (or HTIS ffliü...Investigator. The Air Force Technical Monitor was James W. Brinkley of the Impact Branch, Biodynamics and Bionics Division of the Aerospace Medical...ACES-II Side Arm Control Handles were Mounted on Strain-Gauged Cantilever Beams which Permit "In-Out" and "Forward-Back" Forces to be Measured 18

  6. Measurement of the traction force of biological cells by digital holography

    Science.gov (United States)

    Yu, Xiao; Cross, Michael; Liu, Changgeng; Clark, David C.; Haynie, Donald T.; Kim, Myung K.

    2011-01-01

    The traction force produced by biological cells has been visualized as distortions in flexible substrata. We have utilized quantitative phase microscopy by digital holography (DH-QPM) to study the wrinkling of a silicone rubber film by motile fibroblasts. Surface deformation and the cellular traction force have been measured from phase profiles in a direct and straightforward manner. DH-QPM is shown to provide highly efficient and versatile means for quantitatively analyzing cellular motility. PMID:22254175

  7. A novel AFM based method for force measurements between individual hair strands

    International Nuclear Information System (INIS)

    Max, Eva; Haefner, Wolfgang; Wilco Bartels, Frank; Sugiharto, Albert; Wood, Claudia; Fery, Andreas

    2010-01-01

    Interactions between hairs and other natural fibers are of broad interest for both applications and fundamental understanding of biological interfaces. We present a novel method, that allows force measurements between individual hair strands. Hair fragments can be laser-cut without altering their surface chemistry. Subsequently, they are glued onto Atomic force microscopy (AFM) cantilevers. This allows carrying out measurements between the hair fragment and surface immobilized hair in a well-defined crossed-cylinder geometry. Both force-distance and friction measurements are feasible. Measurements in air with controlled humidity and in aqueous environment show clear differences which can be explained by the dominating role of capillary interactions in air. Friction is found to be anisotropic, reflecting the fine structure of hair cuticula. While the investigations are focused on the particular example of human hair, we expect that the approach can be extended to other animal/plant fibers and thus offers perspectives for broad spectrum systems.

  8. Measurement of internal forces in superconducting accelerator magnets with strain gauge transducers

    International Nuclear Information System (INIS)

    Goodzeit, C.L.; Anerella, M.D.; Ganetis, G.L.

    1988-01-01

    An improved method has been developed for the measurement of internal forces in superconducting accelerator magnets, in particular the compressive stresses in coils and the end restraint forces on the coils. The transducers have been designed to provide improved sensitivity to purely mechanical strain by using bending mode deflections for sensing the applied loads. Strain gauge resistance measurements are made with a new system that eliminates sources of errors due to spurious resistance changes in interconnecting wiring and solder joints. The design of the transducers and their measurement system is presented along with a discussion of the method of compensation for thermal and magnetic effects, methods of calibration with typical calibration data, and measured effect in actual magnets of the thermal stress changes from cooldown and the Lorentz forces during magnet excitation. 13 figs., 1 tab

  9. A novel AFM based method for force measurements between individual hair strands

    Energy Technology Data Exchange (ETDEWEB)

    Max, Eva; Haefner, Wolfgang [Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95440 Bayreuth (Germany); Wilco Bartels, Frank [Polymer Physics, Global PU Specialties Research, BASF Polyurethanes GmbH, Elastogranstrasse 60, 49448 Lemfoerde (Germany); Sugiharto, Albert [Polymer Physics and Analytics, G201, 67056 Ludwigshafen (Germany); Wood, Claudia [Care Chemicals and Formulators, Personal Care Ingredients, New Business and Application Development, BASF SE, E-EMV/GP - H201, 67056 Ludwigshafen (Germany); Fery, Andreas, E-mail: andreas.fery@uni-bayreuth.de [Physical Chemistry II, University of Bayreuth, Universitaetsstrasse 30, 95440 Bayreuth (Germany)

    2010-03-15

    Interactions between hairs and other natural fibers are of broad interest for both applications and fundamental understanding of biological interfaces. We present a novel method, that allows force measurements between individual hair strands. Hair fragments can be laser-cut without altering their surface chemistry. Subsequently, they are glued onto Atomic force microscopy (AFM) cantilevers. This allows carrying out measurements between the hair fragment and surface immobilized hair in a well-defined crossed-cylinder geometry. Both force-distance and friction measurements are feasible. Measurements in air with controlled humidity and in aqueous environment show clear differences which can be explained by the dominating role of capillary interactions in air. Friction is found to be anisotropic, reflecting the fine structure of hair cuticula. While the investigations are focused on the particular example of human hair, we expect that the approach can be extended to other animal/plant fibers and thus offers perspectives for broad spectrum systems.

  10. Measurement of friction force between two mica surfaces with multiple beam interferometry

    Directory of Open Access Journals (Sweden)

    Jung J.C.

    2010-06-01

    Full Text Available Friction forces play a crucial role in the tribological behaviour of microcomponents and the application of MEMS products. It is necessary to develop a measurement system to understand and control the material characteristics. In this study, a microscopic measurement system based on multiple beam interferometry is developed to measure the friction force between two mica thin films. Some frictional behaviour between the two mica sheets in contact are reported. The evaluated shear strength of mica agrees well to the existing data. It is possible to use the developed system for micro-tribology study.

  11. Cellular dynamics of bovine aortic smooth muscle cells measured using MEMS force sensors

    Science.gov (United States)

    Tsukagoshi, Takuya; Nguyen, Thanh-Vinh; Hirayama Shoji, Kayoko; Takahashi, Hidetoshi; Matsumoto, Kiyoshi; Shimoyama, Isao

    2018-04-01

    Adhesive cells perceive the mechanical properties of the substrates to which they adhere, adjusting their cellular mechanical forces according to their biological characteristics. This mechanical interaction subsequently affects the growth, locomotion, and differentiation of the cell. However, little is known about the detailed mechanism that underlies this interaction between adherent cells and substrates because dynamically measuring mechanical phenomena is difficult. Here, we utilize microelectromechamical systems force sensors that can measure cellular traction forces with high temporal resolution (~2.5 µs) over long periods (~3 h). We found that the cellular dynamics reflected physical phenomena with time scales from milliseconds to hours, which contradicts the idea that cellular motion is slow. A single focal adhesion (FA) generates an average force of 7 nN, which disappears in ms via the action of trypsin-ethylenediaminetetraacetic acid. The force-changing rate obtained from our measurements suggests that the time required for an FA to decompose was nearly proportional to the force acting on the FA.

  12. Temporomandibular disorders and psychological status in adult patients with a deep bite

    DEFF Research Database (Denmark)

    Sonnesen, Liselotte; Svensson, Peter

    2008-01-01

    Temporomandibular disorders (TMDs) and psychological status were examined in adult patients with a deep bite and compared with an adult age- and gender-matched control group with neutral occlusion. The deep bite group consisted of 20 females (mean age 30.3 years) and 10 males (mean age 33.1 years......). The control group comprised 20 females (mean age 29.4 years) and 10 males (mean age 34.2 years). TMD examination, according to the Research Diagnostic Criteria for TMD (RDC/TMD), cephalometric lateral radiographs, registration of occlusion, and bite force were performed. To test the mean differences between...... group compared with the controls. Somatization scores were significantly higher in the deep bite group compared with the controls (P psychological...

  13. Bites, stings, and rigors: clinical considerations in African operations.

    Science.gov (United States)

    Lynch, James H; Verlo, April R; Givens, Melissa L; Munoz, Cesar E

    2014-01-01

    The natural health threats in Africa pose daunting clinical challenges for any provider, as evidenced by the current Ebola epidemic in West Africa, but the threat is multiplied for the Special Operations provider on the continent who faces these challenges with limited resources and the tyranny of distance. The majority of operationally significant health risks can be mitigated by strict adherence to a comprehensive force health protection plan. The simplest, yet most effective, technique for preventing mosquito-borne diseases is the prevention of mosquito bites with repellent, bed nets, and appropriate clothing in addition to chemoprophylaxis. Some of the more likely or lethal infectious diseases encountered on the continent include malaria, Chikungunya, dengue, human immunodeficiency virus, and Ebola. Venomous snakes pose a particular challenge since the treatment can be as deadly as the injury. Providers supporting African operations should educate themselves on the clinical characteristics of possible envenomations in their area while promoting snake avoidance as the primary mitigation measure. To succeed in Africa, the Special Operations provider must consider how to meet these challenges in an environment where there may not be reliable evacuation, hospitalization, or logistics channels. 2014.

  14. Static and dynamic force/moment measurements in the Eidetics water tunnel

    Science.gov (United States)

    Suarez, Carlos J.; Malcolm, Gerald N.

    1994-01-01

    Water tunnels have been utilized in one form or another to explore fluid mechanics and aerodynamics phenomena since the days of Leonardo da Vinci. Water tunnel testing is attractive because of the relatively low cost and quick turn-around time to perform flow visualization experiments and evaluate the results. The principal limitation of a water tunnel is that the low flow speed, which provides for detailed visualization, also results in very small hydrodynamic (aerodynamic) forces on the model, which, in the past, have proven to be difficult to measure accurately. However, the advent of semi-conductor strain gage technology and devices associated with data acquisition such as low-noise amplifiers, electronic filters, and digital recording have made accurate measurements of very low strain levels feasible. The principal objective of this research effort was to develop a multi-component strain gage balance to measure forces and moments on models tested in flow visualization water tunnels. A balance was designed that allows measuring normal and side forces, and pitching, yawing and rolling moments (no axial force). The balance mounts internally in the model and is used in a manner typical of wind tunnel balances. The key differences between a water tunnel balance and a wind tunnel balance are the requirement for very high sensitivity since the loads are very low (typical normal force is 0.2 lbs), the need for water proofing the gage elements, and the small size required to fit into typical water tunnel models.

  15. An implantable telemetry device to measure intra-articular tibial forces.

    Science.gov (United States)

    D'Lima, Darryl D; Townsend, Christopher P; Arms, Steven W; Morris, Beverly A; Colwell, Clifford W

    2005-02-01

    Tibial forces are important because they determine polyethylene wear, stress distribution in the implant, and stress transfer to underlying bone. Theoretic estimates of tibiofemoral forces have varied between three and six times the body weight depending on the mathematical models used and the type of activity analyzed. An implantable telemetry system was therefore developed to directly measure tibiofemoral compressive forces. This system was tested in a cadaver knee in a dynamic knee rig. A total knee tibial arthroplasty prosthesis was instrumented with four force transducers located at the four corners of the tibial tray. These transducers measured the total compressive forces on the tibial tray and the location of the center of pressure. A microprocessor performed analog-to-digital signal conversion and performed pulse code modulation of a surface acoustic wave radio frequency oscillator. This signal was then transmitted through a single pin hermetic feed-through tantalum wire antenna located at the tip of the stem. The radio frequency signal was received by an external antenna connected to a receiver and to a computer for data acquisition. The prosthesis was powered by external coil induction. The tibial transducer accurately measured both the magnitude and the location of precisely applied external loads. Successful transmission of the radio frequency signal up to a range of 3m was achieved through cadaveric bone, bone cement, and soft tissue. Reasonable accuracy was obtained in measuring loads applied through a polyethylene insert. The implant was also able to detect unicondylar loading with liftoff.

  16. Non-Newtonian Gravity and New Weak Forces: an Index of Measurements and Theory

    Science.gov (United States)

    Fischbach, E.; Gillies, G. T.; Krause, D. E.; Schwan, J. G.; Talmadge, C.

    1992-01-01

    The precise measurement of weak effects plays a pivotal role in metrology and in the determination of the fundamental constants. Hence, the possibility of new weak forces, and the related question of non-Newtonian behaviour of the gravitational force, have been of special interest to both measurement scientists and those involved in precise tests of physical laws. To date there is no compelling evidence for any deviations from the predictions of Newtonian gravity in the nonrelativistic weak-field regime. A significant literature on this question has developed over the past few years, and a host of experiments and theoretical scenarios have been discussed. Moreover, a very close relationship exists between the experimental methodologies used to determine the absolute value of the Newtonian gravitational constant G, and those employed in searches for new weak forces and for breakdowns in the inverse-square law of gravity. We have therefore prepared a new index of measurements of such effects, using the original bibliographic work of Gillies as a starting point, but also including citations to the appropriate theoretical papers in the field. The focus of the present version of the index is then studies of the "fifth force", measurements of gravitational effects on antimatter, searches for a spin-component in the gravitational force, and related phenomena.

  17. Hilbert phase dynamometry (HPD) for real-time measurement of cell generated forces (Conference Presentation)

    Science.gov (United States)

    Sridharan, Shamira; Li, Yanfen; Bhaduri, Basanta; Majeed, Hassaan; Dupenloup, Paul; Levine, Alex; Kilian, Kristopher A.; Popescu, Gabriel

    2016-03-01

    Traction force microscopy is the most widely used technique for studying the forces exerted by cells on deformable substrates. However, the method is computationally intense and cells have to be detached from the substrate prior to measuring the displacement map. We have developed a new method, referred to as Hilbert phase dynamometry (HPD), which yields real-time force fields and, simultaneously, cell dry mass and growth information. HPD operates by imaging cells on a deformable substrate that is patterned with a grid of fluorescent proteins. A Hilbert transform is used to extract the phase map associated with the grid deformation, which provides the displacement field. By combining this information with substrate stiffness, an elasticity model was developed to measure forces exerted by cells with high spatial resolution. In our study, we prepared 10kPa gels and them with a 2-D grid of FITC-conjugated fibrinogen/fibronectin mixture, an extracellular matrix protein to which cells adhere. We cultured undifferentiated mesenchymal stem cells (MSC), and MSCs that were in the process of undergoing adipogenesis and osteogenesis. The cells were measured over the course of 24 hours using Spatial Light Interference Microscopy (SLIM) and wide-field epi-fluorescence microscopy allowing us to simultaneously measure cell growth and the forces exerted by the cells on the substrate.

  18. Epidemiology of dog bite, a potential source of rabies in Guilan, north of Iran

    Directory of Open Access Journals (Sweden)

    Zahra Mohtasham-Amiri

    2015-06-01

    Full Text Available Objective: To determine epidemiological aspects of dog bite in Guilan Province, north of Iran. Methods: An analytical cross-sectional study was conducted on 1 643 cases of dog bites who presented at rabies vaccination centers in Guilan, Iran from June 2011 to May 2012. Data including demographic characteristics of dog bite cases, characteristics of biting dog, treatment and preventive measures carried out, and dog bite incident circumstances were collected. Independent t-test, ANOVA, Fisher exact test and chi-square test were used. Results: Dog bite incidences in men and women were 179.4 and 55 in 100 000 populations, respectively. Incidences in urban and rural were 72.8, and 181.9 in 100 000 population, respectively. The highest percentage of victims (20.1% was in 20-29 years old age group. Majority of dogs (92% were owned. Victims in the highest percentage (26.6% were dog owners. Most of dog bites were occurred in houses (58.5%. Entering to the dog’s guarding territory was the most common circumstances (27.6%. Injuries most commonly involved the lower extremities (51%. Rabies vaccine, rabies immunoglobulin, tetanus vaccine and tetanus immunoglobulin were administered for 100%, 23.2%, 74.8%, and 9.1%, respectively. There were significant differences between men and women in term of area and place of bite incidence and dog ownership (P < 0.05. Mean age differences among categories of dog ownership, dog bite circumstance, and bitted site of body were significant (P < 0.05. Conclusions: Designing comprehensive educational programs to reduce dog bite incidence based on gender and age of target groups can be useful.

  19. Phase-resolved fluid dynamic forces of a flapping foil energy harvester based on PIV measurements

    Science.gov (United States)

    Liburdy, James

    2017-11-01

    Two-dimensional particle image velocimetry measurements are performed in a wind tunnel to evaluate the spatial and temporal fluid dynamic forces acting on a flapping foil operating in the energy harvesting regime. Experiments are conducted at reduced frequencies (k = fc/U) of 0.05 - 0.2, pitching angle of, and heaving amplitude of A / c = 0.6. The phase-averaged pressure field is obtained by integrating the pressure Poisson equation. Fluid dynamic forces are then obtained through the integral momentum equation. Results are compared with a simple force model based on the concept of flow impulse. These results help to show the detailed force distributions, their transient nature and aide in understanding the impact of the fluid flow structures that contribute to the power production.

  20. Measurements on hydrophobic and hydrophilic surfaces using a porous gamma alumina nanoparticle aggregate mounted on Atomic Force Microscopy cantilevers

    NARCIS (Netherlands)

    Das, Theerthankar; Becker, Thomas; Nair, Balagopal N.

    2010-01-01

    Atomic Force Microscopy (AFM) measurements are extensively used for a detailed understanding of molecular and surface forces. In this study, we present a technique for measuring such forces, using an AFM cantilever attached with a porous gamma alumina nanoparticle aggregate. The modified cantilever

  1. Harmonic Force Spectroscopy measures load-dependent kinetics of individual human β-cardiac myosin molecules

    DEFF Research Database (Denmark)

    Sung, Jongmin; Nag, Suman; Mortensen, Kim

    2015-01-01

    Molecular motors are responsible for numerous cellular processes from cargo transport to heart contraction. Their interactions with other cellular components are often transient and exhibit kinetics that depend on load. Here, we measure such interactions using ‘harmonic force spectroscopy....... The protocol accumulates statistics fast enough to deliver single-molecule results from single-molecule experiments. We demonstrate the method’s performance by measuring the force-dependent kinetics of individual human b-cardiac myosin molecules interacting with an actin filament at physiological ATP...

  2. Comparison of two treatment strategies for the early treatment of an anterior skeletal open bite : Posterior bite block-vertical pull chin cup (PBB-VPC) vs. posterior bite block-high pull headgear (PBB-HPH).

    Science.gov (United States)

    Turkkahraman, Hakan; Cetin, Ebru

    2017-07-01

    Aim of the present study was to compare the effects of posterior bite block-vertical pull chin cup (PBB-VPC) and posterior bite block-high pull headgear (PBB-HPH) in the early treatment of anterior open bite. This retrospective study was carried out using pretreatment (T1) and posttreatment (T2) lateral cephalometric radiographs of 28 patients treated with either PBB-VPC or PBB-HPH and 14 age-matched control patients with anterior open bite. The treatment changes were evaluated with 20 measurements (7 angular and 13 linear). Intergroup comparisons of the cephalometric measurements were performed by ANOVA, and a post hoc Tukey test was used to perform multiple comparisons. There was no significant difference in the open bite correction between the two treatment groups, but both groups showed significantly greater increases in overbite than the controls (P open bite. Retrusion of the upper/lower incisors and a slight increase in the upper anterior dentoalveolar height were the most evident findings in the PBB-VPC group. In the PBB-HPH group, forward maxillary growth was significantly restricted, ANB and overjet were reduced, and the upper and lower incisors were significantly retruded.

  3. In situ friction measurement on murine cartilage by atomic force microscopy.

    Science.gov (United States)

    Coles, Jeffrey M; Blum, Jason J; Jay, Gregory D; Darling, Eric M; Guilak, Farshid; Zauscher, Stefan

    2008-01-01

    Articular cartilage provides a low-friction, wear-resistant surface for the motion of diarthrodial joints. The objective of this study was to develop a method for in situ friction measurement of murine cartilage using a colloidal probe attached to the cantilever of an atomic force microscope. Sliding friction was measured between a chemically functionalized microsphere and the cartilage of the murine femoral head. Friction was measured at normal loads ranging incrementally from 20 to 100 nN with a sliding speed of 40 microm/s and sliding distance of 64 microm. Under these test conditions, hydrostatic pressurization and biphasic load support in the cartilage were minimized, providing frictional measurements that predominantly reflect boundary lubrication properties. Friction coefficients measured on murine tissue (0.25+/-0.11) were similar to those measured on porcine tissue (0.23+/-0.09) and were in general agreement with measurements of boundary friction on cartilage by other researchers. Using the colloidal probe as an indenter, the elastic mechanical properties and surface roughness were measured in the same configuration. Interfacial shear was found to be the principal mechanism of friction generation, with little to no friction resulting from plowing forces, collision forces, or energy losses due to normal deformation. This measurement technique can be applied to future studies of cartilage friction and mechanical properties on genetically altered mice or other small animals.

  4. Pigs suffering from injurious behaviours like flank biting and tail biting are more interested to manipulate a novel rope than uninjured control animals

    NARCIS (Netherlands)

    Bracke, M.B.M.; Ettema, K.

    2014-01-01

    Injurious behaviours in pigs may involve persistent or forceful biting in specific body parts and may result in wounds of the pigs’ tails, ears, flanks and legs. Such behaviours, which may lead to progressive tissue damage, are difficult to counteract. On a commercial farm 22 groups of pigs with

  5. The influence of bite size and multiple bites on oral texture sensations

    NARCIS (Netherlands)

    Wijk, de R.A.; Engelen, L.; Prinz, J.F.; Weenen, H.

    2003-01-01

    The influence of bite size on sensory mouth- and afterfeel sensations was explored in two studies in which single bites of vanilla custard desserts were varied from 2 to 11 ml (study 1) and in which series of five bites of two different custard desserts were presented consecutively (study 2). In

  6. The influence of bite size and multiple bites on oral texture sensations

    NARCIS (Netherlands)

    Wijk, R.A. de; Engelen, L.; Prinz, J.F.; Weenen, H.

    2003-01-01

    The influence of bite size on sensory mouthfeel and afterfeel sensations was explored in two studies in which single bites of vanilla custard desserts were varied from 2 to 11 mL (study 1) and in which series of five bites of two different custard desserts were presented consecutively (study 2). In

  7. An Epidemiological Study of Animal Bites and Envenomings in a Rural District of Tamilnadu, India

    Directory of Open Access Journals (Sweden)

    Venkatesan M

    2014-12-01

    Full Text Available Aim: To find out the period prevalence of animal bites and envenomings, its epidemiological risk factors and treatment seeking behaviour. Materials and methods: The present cross sectional study was conducted in the 34 villages of the field practising areas of the Rural Health Training Centre, Thiruvenainallur. Considering the prevalence of bites as 7.4%, and taking 5 members in each household with a non response of 10% the number households studied were 4150 covering a population of 18865 which was calculated using an Open EPI version (2.3 software package. Sampling frame of households was prepared and systemic random sampling method was used to select households from each village. Trained medical interns and social workers collected information on bites in the preceding one year. Data was entered and analyzed in Epi_info (3.4.3 software. Results: In this study, information of 12947 adults was included and the overall period prevalence of bites was 81.8/1000 population. The most common bite is dog bite (22.3 followed by scorpion (22.1 and centipede (17.8 per 1000 population. The dog bites are significantly higher among males, people below the poverty line, farmers and laborers. There is significantly increased risk of snake bites among people working in agriculture fields. Only 35% of the dog bite victims washed their wound with soap and water and 28% applied irritants such as ash, ink, calotropis milk etc. over the wounds. Anti-rabies vaccination was given in 60% of the dog bite victims and life saving measure of Rabies Immunoglobulins (RIGS was given in only in 6.2%. Almost half of the bitten victims of scorpion and centipede follow traditional methods of treatment. Conclusions: Considering the high prevalence of different bites and treatment seeking behavior indicates there is a lack of awareness regarding all forms of bites in the rural community. The existing program of rabies control has to be strengthened and community awareness about

  8. Investigating the adsorption of the gemini surfactant "12-2-12" onto mica using atomic force microscopy and surface force apparatus measurements

    NARCIS (Netherlands)

    Fielden, ML; Claesson, PM; Verrall, RE

    1999-01-01

    The adsorption of the cationic gemini surfactant 1,2-bis(n-dodecyldimethylammonium)ethane dibromide on mica was followed by measuring forces between mica surfaces and by atomic force microscopy (AFM) imaging. The surface charge was found to be neutralized at total surfactant concentrations between 8

  9. Direct measurement and modulation of single-molecule coordinative bonding forces in a transition metal complex

    DEFF Research Database (Denmark)

    Hao, Xian; Zhu, Nan; Gschneidtner, Tina

    2013-01-01

    remain a daunting challenge. Here we demonstrate an interdisciplinary and systematic approach that enables measurement and modulation of the coordinative bonding forces in a transition metal complex. Terpyridine is derived with a thiol linker, facilitating covalent attachment of this ligand on both gold...... substrate surfaces and gold-coated atomic force microscopy tips. The coordination and bond breaking between terpyridine and osmium are followed in situ by electrochemically controlled atomic force microscopy at the single-molecule level. The redox state of the central metal atom is found to have......Coordination chemistry has been a consistently active branch of chemistry since Werner's seminal theory of coordination compounds inaugurated in 1893, with the central focus on transition metal complexes. However, control and measurement of metal-ligand interactions at the single-molecule level...

  10. Measurement and prediction of cutting forces and vibrations on longwall shearers

    Energy Technology Data Exchange (ETDEWEB)

    Bulent Tiryaki [CRCMining (Australia)

    2006-12-15

    CRCMining has developed the Cutting Head Performance Analysis Software (CPAS) to predict cutter motor power, ranging arm reaction forces, and vibrations for different drum designs, coal seams, and shearer operational conditions. This project describes the work on THE DBT EL3000 shearer at Beltana to validate/update CPAS by measuring the cutter motor power, ranging arm vibrations, and reaction forces through an online data acquisition system called Cutting Head Performance Monitoring System (CPMS). This system records the outputs of six strain gauge bridges, six accelerometers, and two pressure transducers on ranging arms during underground coal production. CPAS2 has then been developed in order to eliminate the needs for performing coal cutting tests for the target coal seam. CPAS2 simulations for cutter motor power, vertical reaction force, and vibrations were also close to those measured in the trials. CRCMining will release the CPAS code including fully functioning software code on CD to Australian coal mining industry.

  11. Measurement of levitation force and critical current density of melt textured YBa2Cu3Ox

    International Nuclear Information System (INIS)

    Lehndorff, B.; Kuerschner, H.G.; Busch, D.; Fischer, B.; Piel, H.

    1993-01-01

    By various Melt Textured Growth (MTG) processes YBa 2 Cu 3 O x (Y-123) samples have been prepared with high critical current densities and high levitation forces. The best value of both have been reported by Murakami et al., who used the melt powder melt growth (MPMG) process with platinum addition. These melt textured samples are applicable to magnetic bearings (3). The goal of this work is to develop technical High Temperature Superconductors (HTSC) for bearings and magnet application. In order to optimize the HTSC material for this purpose, levitation force and critical current measurements were carried out. Within this work samples were prepared by the modified Salama method. Levitation force was measured as a function of the distance between the magnet and the superconductor. The critical current density was determined by an inductive method. (orig.)

  12. Minimising the effect of nanoparticle deformation in intermittent contact amplitude modulation atomic force microscopy measurements

    International Nuclear Information System (INIS)

    Babic, Bakir; Lawn, Malcolm A.; Coleman, Victoria A.; Jämting, Åsa K.; Herrmann, Jan

    2016-01-01

    The results of systematic height measurements of polystyrene (PS) nanoparticles using intermittent contact amplitude modulation atomic force microscopy (IC-AM-AFM) are presented. The experimental findings demonstrate that PS nanoparticles deform during AFM imaging, as indicated by a reduction in the measured particle height. This deformation depends on the IC-AM-AFM imaging parameters, material composition, and dimensional properties of the nanoparticles. A model for nanoparticle deformation occurring during IC-AM-AFM imaging is developed as a function of the peak force which can be calculated for a particular set of experimental conditions. The undeformed nanoparticle height can be estimated from the model by extrapolation to zero peak force. A procedure is proposed to quantify and minimise nanoparticle deformation during IC-AM-AFM imaging, based on appropriate adjustments of the experimental control parameters.

  13. A Noncontact Force Sensor Based on a Fiber Bragg Grating and Its Application for Corrosion Measurement

    Directory of Open Access Journals (Sweden)

    Antonio C. Bruno

    2013-08-01

    Full Text Available A simple noncontact force sensor based on an optical fiber Bragg grating attached to a small magnet has been proposed and built. The sensor measures the force between the magnet and any ferromagnetic material placed within a few millimeters of the sensor. Maintaining the sensor at a constant standoff distance, material loss due to corrosion increases the distance between the magnet and the corroded surface, which decreases the magnetic force. This will decrease the strain in the optical fiber shifting the reflected Bragg wavelength. The measured shift for the optical fiber used was 1.36 nm per Newton. Models were developed to optimize the magnet geometry for a specific sensor standoff distance and for particular corrosion pit depths. The sensor was able to detect corrosion pits on a fuel storage tank bottom with depths in the sub-millimeter range.

  14. Bug bites and stings: When to see a dermatologist

    Medline Plus

    Full Text Available ... de12", ]; for (var c = 0; c Tips to prevent and treat bug bites Although most bug bites ... take steps to reduce your risk. To help prevent bug bites, dermatologists recommend the following tips: Use ...

  15. Atomic force microscope adhesion measurements and atomistic molecular dynamics simulations at different humidities

    International Nuclear Information System (INIS)

    Seppä, Jeremias; Sairanen, Hannu; Korpelainen, Virpi; Husu, Hannu; Heinonen, Martti; Lassila, Antti; Reischl, Bernhard; Raiteri, Paolo; Rohl, Andrew L; Nordlund, Kai

    2017-01-01

    Due to their operation principle atomic force microscopes (AFMs) are sensitive to all factors affecting the detected force between the probe and the sample. Relative humidity is an important and often neglected—both in experiments and simulations—factor in the interaction force between AFM probe and sample in air. This paper describes the humidity control system designed and built for the interferometrically traceable metrology AFM (IT-MAFM) at VTT MIKES. The humidity control is based on circulating the air of the AFM enclosure via dryer and humidifier paths with adjustable flow and mixing ratio of dry and humid air. The design humidity range of the system is 20–60 %rh. Force–distance adhesion studies at humidity levels between 25 %rh and 53 %rh are presented and compared to an atomistic molecular dynamics (MD) simulation. The uncertainty level of the thermal noise method implementation used for force constant calibration of the AFM cantilevers is 10 %, being the dominant component of the interaction force measurement uncertainty. Comparing the simulation and the experiment, the primary uncertainties are related to the nominally 7 nm radius and shape of measurement probe apex, possible wear and contamination, and the atomistic simulation technique details. The interaction forces are of the same order of magnitude in simulation and measurement (5 nN). An elongation of a few nanometres of the water meniscus between probe tip and sample, before its rupture, is seen in simulation upon retraction of the tip in higher humidity. This behaviour is also supported by the presented experimental measurement data but the data is insufficient to conclusively verify the quantitative meniscus elongation. (paper)

  16. Three-Dimensional Force Measurements During Rapid Palatal Expansion in Sus scrofa

    Directory of Open Access Journals (Sweden)

    Kelly Goeckner

    2016-04-01

    Full Text Available Rapid palatal expansion is an orthodontic procedure widely used to correct the maxillary arch. However, its outcome is significantly influenced by factors that show a high degree of variability amongst patients. The traditional treatment methodology is based on an intuitive and heuristic treatment approach because the forces applied in the three dimensions are indeterminate. To enable optimal and individualized treatment, it is essential to measure the three-dimensional (3D forces and displacements created by the expander. This paper proposes a method for performing these 3D measurements using a single embedded strain sensor, combining experimental measurements of strain in the palatal expander with 3D finite element analysis (FEA. The method is demonstrated using the maxillary jaw from a freshly euthanized pig (Sus scrofa and a hyrax-design rapid palatal expander (RPE appliance with integrated strain gage. The strain gage measurements are recorded using a computer interface, following which the expansion forces and extent of expansion are estimated by FEA. A total activation of 2.0 mm results in peak total force of about 100 N—almost entirely along the direction of expansion. The results also indicate that more than 85% of the input activation is immediately transferred to the palate and/or teeth. These studies demonstrate a method for assessing and individualizing expansion magnitudes and forces during orthopedic expansion of the maxilla. This provides the basis for further development of smart orthodontic appliances that provide real-time readouts of forces and movements, which will allow personalized, optimal treatment.

  17. [Hip abduction force measured by a new method and its relation to EMG activity].

    Science.gov (United States)

    Murakami, K

    1989-11-01

    I measured hip abduction force using a new device of my own design and evaluated the correlation between hip abduction force and electromyographic (EMG) activity of the gluteus medius, gluteus maximus, rectus femoris and adductor longus in 20 normal adults. Hip abduction force showed a maximum value on starting and decreased during abduction of the hip joint. Durability, on the other hand, showed an increase. The attenuation curve was approximated to the exponential function A.e-Kt; A and l/k indicating maximum hip abduction force and durability, respectively. Maximum hip abduction force was about 20 kg and durability was about 160 seconds on starting hip abduction. The regression coefficient between hip abduction force and EMG activity of the gluteus medius, gluteus maximus, rectus femoris and adductor longus was 1.5, 06, 0.6 and 0.2 respectively. From these results, I concluded that although the gluteus medius plays the major role in hip abduction, the rectus femoris and gluteus maximus may act as stabilizers for maintaining the position of hip abduction.

  18. Numerical and experimental study on vorticity measurement in liquid metal using local Lorentz force velocimetry

    Science.gov (United States)

    Hernández, Daniel; Marangoni, Rafael; Schleichert, Jan; Karcher, Christian; Fröhlich, Thomas; Wondrak, Thomas

    2018-03-01

    Local Lorentz force velocimetry (local LFV) is a contactless velocity measurement technique for liquid metals. Due to the relative movement between an electrically conductive fluid and a static applied magnetic field, eddy currents and a flow-braking Lorentz force are generated inside the metal melt. This force is proportional to the flow rate or to the local velocity, depending on the volume subset of the flow spanned by the magnetic field. By using small-size magnets, a localized magnetic field distribution is achieved allowing a local velocity assessment in the region adjacent to the wall. In the present study, we describe a numerical model of our experiments at a continuous caster model where the working fluid is GaInSn in eutectic composition. Our main goal is to demonstrate that this electromagnetic technique can be applied to measure vorticity distributions, i.e. to resolve velocity gradients as well. Our results show that by using a cross-shaped magnet system, the magnitude of the torque perpendicular to the surface of the mold significantly increases improving its measurement in a liquid metal flow. According to our numerical model, this torque correlates with the vorticity of the velocity in this direction. Before validating our numerical predictions, an electromagnetic dry calibration of the measurement system composed of a multicomponent force and torque sensor and a cross-shaped magnet was done using a rotating disk made of aluminum. The sensor is able to measure simultaneously all three components of force and torque, respectively. This calibration step cannot be avoided and it is used for an accurate definition of the center of the magnet with respect to the sensor’s coordinate system for torque measurements. Finally, we present the results of the experiments at the mini-LIMMCAST facility showing a good agreement with the numerical model.

  19. Development of a quartz tuning-fork-based force sensor for measurements in the tens of nanoNewton force range during nanomanipulation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Oiko, V. T. A., E-mail: oiko@ifi.unicamp.br; Rodrigues, V.; Ugarte, D. [Instituto de Física “Gleb Wataghin,” Univ. Estadual de Campinas (UNICAMP), Campinas 13083-859 (Brazil); Martins, B. V. C. [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Silva, P. C. [Laboratório Nacional de Nanotecnologia, CNPEM, Campinas 13083-970 (Brazil)

    2014-03-15

    Understanding the mechanical properties of nanoscale systems requires new experimental and theoretical tools. In particular, force sensors compatible with nanomechanical testing experiments and with sensitivity in the nN range are required. Here, we report the development and testing of a tuning-fork-based force sensor for in situ nanomanipulation experiments inside a scanning electron microscope. The sensor uses a very simple design for the electronics and it allows the direct and quantitative force measurement in the 1–100 nN force range. The sensor response is initially calibrated against a nN range force standard, as, for example, a calibrated Atomic Force Microscopy cantilever; subsequently, applied force values can be directly derived using only the electric signals generated by the tuning fork. Using a homemade nanomanipulator, the quantitative force sensor has been used to analyze the mechanical deformation of multi-walled carbon nanotube bundles, where we analyzed forces in the 5–40 nN range, measured with an error bar of a few nN.

  20. Flexible Piezoelectric Tactile Sensor Array for Dynamic Three-Axis Force Measurement.

    Science.gov (United States)

    Yu, Ping; Liu, Weiting; Gu, Chunxin; Cheng, Xiaoying; Fu, Xin

    2016-06-03

    A new flexible piezoelectric tactile sensor array based on polyvinylidene fluoride (PVDF) film is proposed for measuring three-axis dynamic contact force distribution. The array consists of six tactile units arranged as a 3 × 2 matrix with spacing 8 mm between neighbor units. In each unit, a PVDF film is sandwiched between four square-shaped upper electrodes and one square-shaped lower electrode, forming four piezoelectric capacitors. A truncated pyramid bump is located above the four piezoelectric capacitors to improve force transmission. A three-axis contact force transmitted from the top of the bump will lead to the four piezoelectric capacitors underneath undergoing different charge changes, from which the normal and shear components of the force can be calculated. A series of dynamic tests have been carried out by exerting sinusoidal forces with amplitudes ranging from 0 to 0.5 N in the x-axis, 0 to 0.5 N in the y-axis, and 0 to 1.5 N in the z-axis, separately. The tactile units show good sensitivities with 14.93, 14.92, and 6.62 pC/N in the x-, y-, and z-axes, respectively. They can work with good linearity, relatively low coupling effect, high repeatability, and acceptable frequency response in the range of 5-400 Hz to both normal and shear load. In addition, dynamic three-axis force measurement has been conducted for all of the tactile units. The average errors between the applied and calculated forces are 10.68% ± 6.84%. Furthermore, the sensor array can be easily integrated onto a curved surface, such as robotic and prosthetic hands, due to its excellent flexibility.

  1. Flexible Piezoelectric Tactile Sensor Array for Dynamic Three-Axis Force Measurement

    Directory of Open Access Journals (Sweden)

    Ping Yu

    2016-06-01

    Full Text Available A new flexible piezoelectric tactile sensor array based on polyvinylidene fluoride (PVDF film is proposed for measuring three-axis dynamic contact force distribution. The array consists of six tactile units arranged as a 3 × 2 matrix with spacing 8 mm between neighbor units. In each unit, a PVDF film is sandwiched between four square-shaped upper electrodes and one square-shaped lower electrode, forming four piezoelectric capacitors. A truncated pyramid bump is located above the four piezoelectric capacitors to improve force transmission. A three-axis contact force transmitted from the top of the bump will lead to the four piezoelectric capacitors underneath undergoing different charge changes, from which the normal and shear components of the force can be calculated. A series of dynamic tests have been carried out by exerting sinusoidal forces with amplitudes ranging from 0 to 0.5 N in the x-axis, 0 to 0.5 N in the y-axis, and 0 to 1.5 N in the z-axis, separately. The tactile units show good sensitivities with 14.93, 14.92, and 6.62 pC/N in the x-, y-, and z-axes, respectively. They can work with good linearity, relatively low coupling effect, high repeatability, and acceptable frequency response in the range of 5–400 Hz to both normal and shear load. In addition, dynamic three-axis force measurement has been conducted for all of the tactile units. The average errors between the applied and calculated forces are 10.68% ± 6.84%. Furthermore, the sensor array can be easily integrated onto a curved surface, such as robotic and prosthetic hands, due to its excellent flexibility.

  2. Measurement of Levitation Forces of High-"T[subscript c] Superconductors

    Science.gov (United States)

    Becker, M.; Koblischka, M. R.; Hartmann, U.

    2010-01-01

    We show the construction of a so-called levitation balance which is capable of measuring the levitation forces between a permanent magnet and a superconducting high-T[subscript c] thin film sample. The underlying theoretical basis is discussed in detail. The experiment is performed as an introductory physics experiment for school students as well…

  3. Validity and reliability of strain gauge measurement of volitional quadriceps force in patients with COPD.

    Science.gov (United States)

    Machado Rodrigues, Fernanda; Demeyer, Heleen; Hornikx, Miek; Camillo, Carlos Augusto; Calik-Kutukcu, Ebru; Burtin, Chris; Janssens, Wim; Troosters, Thierry; Osadnik, Christian

    2017-08-01

    This study investigated the validity and reliability of fixed strain gauge measurements of isometric quadriceps force in patients with chronic obstructive pulmonary disease (COPD). A total cohort of 138 patients with COPD were assessed. To determine validity, maximal volitional quadriceps force was evaluated during isometric maximal voluntary contraction (MVC) manoeuvre via a fixed strain gauge dynamometer and compared to (a) potentiated non-volitional quadriceps force obtained via magnetic stimulation of the femoral nerve (twitch (Tw); n = 92) and (b) volitional computerized dynamometry (Biodex; n = 46) and analysed via correlation coefficients. Test-retest and absolute reliability were determined via calculations of intra-class correlation coefficients (ICCs), smallest real differences (SRDs) and standard errors of measurement (SEMs). For this, MVC recordings in each device were performed across two test sessions separated by a period of 7 days ( n = 46). Strain gauge measures of MVC demonstrated very large correlation with Tw and Biodex results ( r = 0.86 and 0.88, respectively, both p gauge and Biodex devices (ICC = 0.96 vs. 0.93; SEM = 8.50 vs. 10.54 N·m and SRD = 23.59 vs. 29.22 N·m, respectively). The results support that strain gauge measures of quadriceps force are valid and reliable in patients with COPD.

  4. Force Measurements on a 1/40-scale Model of the U. S. Airship "Akron."

    Science.gov (United States)

    Freeman, Hugh B

    1933-01-01

    This report describes a series of tests made on a 1/40-scale model of the U. S. Airship "Akron" (ZRS-4) for the purpose of determining the drag, lift, and pitching moments of the bare hull and of the hull equipped with two different sets of fins. Measurements were also made of the elevator forces and hinge moments.

  5. THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY

    Science.gov (United States)

    THE EFFECT OF SUBMAXIMAL INHALATION ON MEASURES DERIVED FROM FORCED EXPIRATORY SPIROMETRY. William F. McDonnell Human Studies Division, NHEERL, U.S. Environmental Protection Agency, RTP, NC 27711. Short-term exposure to ozone results in a neurally-mediated decrease in the ab...

  6. The Measurement of Non-Linear Forces and Moments by Means of Free Flight Tests

    National Research Council Canada - National Science Library

    Murphy, Charles

    1956-01-01

    .... Excellent internal consistency has been observed in measuring non-linear normal and Magnus forces and their moments and, in all cases where wind tunnel results were available, they were in good agreement with range results. The application of this technique to the equally important problem of predicting yawing motion is described.

  7. Elastic-properties measurement at high temperatures through contact resonance atomic force microscopy

    DEFF Research Database (Denmark)

    Marinello, Francesco; Pezzuolo, Andrea; Carmignato, Simone

    2015-01-01

    fast direct and non-destructive measurement of Young's modulus and related surface parameters.In this work an instrument set up for Contact Resonance Atomic Force Microscopy is proposed, where the sample with is coupled to a heating stage and a piezoelectric transducer directly vibrate the cantilever...

  8. Variability in Measurement of Swimming Forces: A Meta-Analysis of Passive and Active Drag

    Science.gov (United States)

    Havriluk, Rod

    2007-01-01

    An analysis was conducted to identify sources of true and error variance in measuring swimming drag force to draw valid conclusions about performance factor effects. Passive drag studies were grouped according to methodological differences: tow line in pool, tow line in flume, and carriage in tow tank. Active drag studies were grouped according to…

  9. Force-displacement measurements of earlywood bordered pits using a mesomechanical tester

    Science.gov (United States)

    Samuel L. Zelinka; Keith J. Bourne; John C. Hermanson; Samuel V. Glass; Adriana Costa; Alex C. Wiedenhoeft

    2015-01-01

    The elastic properties of pit membranes are reported to have important implications in understanding air-seeding phenomena in gymnosperms, and pit aspiration plays a large role in wood technological applications such as wood drying and preservative treatment. Here we present force–displacement measurements for pit membranes of circular bordered pits, collected on a...

  10. Measuring q/m for Water Drops--An Introduction to the Effects of Electrical Forces

    Science.gov (United States)

    Hart, Francis X.

    1974-01-01

    Discusses an experiment which introduces students to the effects of electrical forces on the motion of macroscopic objects. Included are the proecedures of measuring the charge-to-mass ratio from deflections of charged water drops in horizontal fields and the overall charges delivered in a Faraday cup. (CC)

  11. 3D Laboratory Measurements of Forces, Flows, and Collimation in Arched Flux Tubes

    Science.gov (United States)

    Haw, Magnus; Bellan, Paul

    2016-10-01

    Fully 3D, vector MHD force measurements from an arched, current carrying flux tube (flux rope) are presented. The experiment consists of two arched plasma-filled flux ropes each powered by a capacitor bank. The two loops are partially overlapped, as in a Venn diagram, and collide and reconnect during their evolution. B-field data is taken on the lower plasma arch using a 54 channel B-dot probe. 3D volumetric data is acquired by placing the probe at 2700 locations and taking 5 plasma shots at each location. The resulting data set gives high resolution (2cm, 10ns) volumetric B-field data with high reproducibility (deviation of 3% between shots). Taking the curl of the measured 3D B-field gives current densities (J) in good agreement with measured capacitor bank current. The JxB forces calculated from the data have a strong axial component at the base of the current channel and are shown to scale linearly with axial gradients in current density. Assuming force balance in the flux tube minor radius direction, we infer near-Alfvenic axial flows from the footpoint regions which are consistent with the measured axial forces. Flux tube collimation is observed in conjunction with these axial flows. These dynamic processes are relevant to the stability and dynamics of coronal loops. Supported provided by NSF, AFOSR.

  12. Design and Analysis of a Sensor System for Cutting Force Measurement in Machining Processes

    Directory of Open Access Journals (Sweden)

    Qiaokang Liang

    2016-01-01

    Full Text Available Multi-component force sensors have infiltrated a wide variety of automation products since the 1970s. However, one seldom finds full-component sensor systems available in the market for cutting force measurement in machine processes. In this paper, a new six-component sensor system with a compact monolithic elastic element (EE is designed and developed to detect the tangential cutting forces Fx, Fy and Fz (i.e., forces along x-, y-, and z-axis as well as the cutting moments Mx, My and Mz (i.e., moments about x-, y-, and z-axis simultaneously. Optimal structural parameters of the EE are carefully designed via simulation-driven optimization. Moreover, a prototype sensor system is fabricated, which is applied to a 5-axis parallel kinematic machining center. Calibration experimental results demonstrate that the system is capable of measuring cutting forces and moments with good linearity while minimizing coupling error. Both the Finite Element Analysis (FEA and calibration experimental studies validate the high performance of the proposed sensor system that is expected to be adopted into machining processes.

  13. Trial manufacture of rotary friction tester and frictional force measurement of metals

    CERN Document Server

    Abe, T; Kanari, M; Tanzawa, S

    2002-01-01

    In the plasma confinement type fusion reactor, in-vessel structures such as a blanket module slide at the joints each other when plasma disruption occurs, and then frictional heat is generated there. Therefore, for the selection of material and the use as the design data, it is important to understand the frictional characteristics of metals and ceramic films in the vacuum. In the present study, we have manufactured a prototype of rotary friction tester and examined the performances of the tester. The frictional characteristics of metals in the room air was measured using the friction tester, and the results obtained are as follows. A drifting friction force for a constant time and a friction force during the idling were 98 mN and 225 mN, respectively. These values were sufficiently small as compared to pressing load (9.8 - 57.8 N) used in the friction test. In a friction force measurement of stainless steel, dynamic friction force obeyed Amontons' law which indicated that dynamic friction force is not depend...

  14. Interface bonding in silicon oxide nanocontacts: interaction potentials and force measurements

    Science.gov (United States)

    Wierez-Kien, M.; Craciun, A. D.; Pinon, A. V.; Le Roux, S.; Gallani, J. L.; Rastei, M. V.

    2018-04-01

    The interface bonding between two silicon-oxide nanoscale surfaces has been studied as a function of atomic nature and size of contacting asperities. The binding forces obtained using various interaction potentials are compared with experimental force curves measured in vacuum with an atomic force microscope. In the limit of small nanocontacts (typically measured with sensitive probes the bonding is found to be influenced by thermal-induced fluctuations. Using interface interactions described by Morse, embedded atom model, or Lennard-Jones potential within reaction rate theory, we investigate three bonding types of covalent and van der Waals nature. The comparison of numerical and experimental results reveals that a Lennard-Jones-like potential originating from van der Waals interactions captures the binding characteristics of dry silicon oxide nanocontacts, and likely of other nanoscale materials adsorbed on silicon oxide surfaces. The analyses reveal the importance of the dispersive surface energy and of the effective contact area which is altered by stretching speeds. The mean unbinding force is found to decrease as the contact spends time in the attractive regime. This contact weakening is featured by a negative aging coefficient which broadens and shifts the thermal-induced force distribution at low stretching speeds.

  15. Design and Analysis of a Sensor System for Cutting Force Measurement in Machining Processes.

    Science.gov (United States)

    Liang, Qiaokang; Zhang, Dan; Coppola, Gianmarc; Mao, Jianxu; Sun, Wei; Wang, Yaonan; Ge, Yunjian

    2016-01-07

    Multi-component force sensors have infiltrated a wide variety of automation products since the 1970s. However, one seldom finds full-component sensor systems available in the market for cutting force measurement in machine processes. In this paper, a new six-component sensor system with a compact monolithic elastic element (EE) is designed and developed to detect the tangential cutting forces Fx, Fy and Fz (i.e., forces along x-, y-, and z-axis) as well as the cutting moments Mx, My and Mz (i.e., moments about x-, y-, and z-axis) simultaneously. Optimal structural parameters of the EE are carefully designed via simulation-driven optimization. Moreover, a prototype sensor system is fabricated, which is applied to a 5-axis parallel kinematic machining center. Calibration experimental results demonstrate that the system is capable of measuring cutting forces and moments with good linearity while minimizing coupling error. Both the Finite Element Analysis (FEA) and calibration experimental studies validate the high performance of the proposed sensor system that is expected to be adopted into machining processes.

  16. Novel universal system for 3-dimensional orthodontic force-moment measurements and its clinical use.

    Science.gov (United States)

    Mencattelli, Margherita; Donati, Elisa; Cultrone, Massimo; Stefanini, Cesare

    2015-07-01

    Orthodontic treatment is an important part of dental health care in Europe: the percentages of the population undergoing therapy vary from 10% to 55%. Therefore, quantifying effective orthodontic loads is a challenging topic with regard to the predictability of tooth movements and the reduction of traumatic side effects. A customized measuring platform was developed and used for detecting orthodontic forces in a range between 0.1 and 2 N. The system consists of 6 load cells, each equipped with 6 strain gauges. The tests were conducted on a 3-dimensional printed malocclused mouth model and on a plaster cast. Four types of superelastic ligation and 2 types of invisible aligners were tested to analyze, respectively, a malocclusion with a high maxillary canine, and the effects on the axial rotation of a maxillary central incisor with and without a divot in the invisible aligners. Optimal treatment forces are exerted by low-friction wires, especially if they are partially engaged. Moreover, by reducing the treatment force, there is less necessity of anchoring to surrounding teeth, thus decreasing the side effects. The efficacy of using invisible aligners with a divot was validated. This platform allowed measurement, at the radicular level, of the resultant forces of orthodontic treatments performed with different orthodontic appliances. In addition to customizing and calibrating the therapy for each patient, this platform could be used to develop new specific instruments able to exert lower treatment forces, thus preventing irreversible damages. Copyright © 2015 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.

  17. A square-force cohesion model and its extraction from bulk measurements

    Science.gov (United States)

    Liu, Peiyuan; Lamarche, Casey; Kellogg, Kevin; Hrenya, Christine

    2017-11-01

    Cohesive particles remain poorly understood, with order of magnitude differences exhibited for prior, physical predictions of agglomerate size. A major obstacle lies in the absence of robust models of particle-particle cohesion, thereby precluding accurate prediction of the behavior of cohesive particles. Rigorous cohesion models commonly contain parameters related to surface roughness, to which cohesion shows extreme sensitivity. However, both roughness measurement and its distillation into these model parameters are challenging. Accordingly, we propose a ``square-force'' model, where cohesive force remains constant until a cut-off separation. Via DEM simulations, we demonstrate validity of the square-force model as surrogate of more rigorous models, when its two parameters are selected to match the two key quantities governing dense and dilute granular flows, namely maximum cohesive force and critical cohesive energy, respectively. Perhaps more importantly, we establish a method to extract the parameters in the square-force model via defluidization, due to its ability to isolate the effects of the two parameters. Thus, instead of relying on complicated scans of individual grains, determination of particle-particle cohesion from simple bulk measurements becomes feasible. Dow Corning Corporation.

  18. Extending calibration-free force measurements to optically-trapped rod-shaped samples

    Science.gov (United States)

    Català, Frederic; Marsà, Ferran; Montes-Usategui, Mario; Farré, Arnau; Martín-Badosa, Estela

    2017-02-01

    Optical trapping has become an optimal choice for biological research at the microscale due to its non-invasive performance and accessibility for quantitative studies, especially on the forces involved in biological processes. However, reliable force measurements depend on the calibration of the optical traps, which is different for each experiment and hence requires high control of the local variables, especially of the trapped object geometry. Many biological samples have an elongated, rod-like shape, such as chromosomes, intracellular organelles (e.g., peroxisomes), membrane tubules, certain microalgae, and a wide variety of bacteria and parasites. This type of samples often requires several optical traps to stabilize and orient them in the correct spatial direction, making it more difficult to determine the total force applied. Here, we manipulate glass microcylinders with holographic optical tweezers and show the accurate measurement of drag forces by calibration-free direct detection of beam momentum. The agreement between our results and slender-body hydrodynamic theoretical calculations indicates potential for this force-sensing method in studying protracted, rod-shaped specimens.

  19. Extending the limits of direct force measurements: colloidal probes from sub-micron particles.

    Science.gov (United States)

    Helfricht, Nicolas; Mark, Andreas; Dorwling-Carter, Livie; Zambelli, Tomaso; Papastavrou, Georg

    2017-07-13

    Direct force measurements by atomic force microscopy (AFM) in combination with the colloidal probe technique are widely used to determine interaction forces in colloidal systems. However, a number of limitations are still preventing a more universal applicability of this technique. Currently, one of the most significant limitations is that only particles with diameters of several micrometers can be used as probe particles. Here, we present a novel approach, based on the combination of nanofluidics and AFM (also referred to as FluidFM-technique), that allows to overcome this size limit and extend the size of suitable probe particles below diameters of 500 nanometers. Moreover, by aspiration of colloidal particles with a hollow AFM-cantilever, the immobilization process is independent of the particle's surface chemistry. Furthermore, the probe particles can be exchanged in situ. The applicability of the FluidFM-technique is demonstrated with silica particles, which are also the types of particles most often used for the preparation of colloidal probes. By comparing 'classical' colloidal probes, i.e. probes from particles irreversibly attached with glue, and various particle sizes aspirated by the FluidFM-technique, we can quantitatively evaluate the instrumental limits. Evaluation of the force profiles demonstrate that even for 500 nm silica particles the diffuse layer properties can be evaluated quantitatively. Therefore, direct force measurements on the level of particle sizes used in industrial formulations will become available in the future.

  20. Spot Surface Labeling of Magnetic Microbeads and Application in Biological Force Measurements

    Science.gov (United States)

    Estes, Ashley; O'Brien, E. Tim; Hill, David; Superfine, Richard

    2006-11-01

    Biological force measurements on single molecules and macromolecular structures often use microbeads for the application of force. These techniques are often complicated by multiple attachments and nonspecific binding. In one set of experiments, we are applying a magnetic force microscope that allows us to pull on magnetic beads attached to ciliated human bronchial epithelial cells. These experiments provide a means to measure the stall force of cilia and understand how cilia propel fluids. However, because we are using beads with diameters of one and 2.8 microns, and the diameter of human airway cilia is approximately 200 nm, we cannot be assured that the bead is bound to a single cilium. To address this, we have developed a sputter coating technique to block the biotin binding capability of the streptavidin labeled bead over its entire surface except for a small spot. These beads may also have applications in other biological experiments such as DNA force experiments in which binding of a single target to an individual bead is critical.

  1. Interactions between Rotavirus and Suwannee River Organic Matter: Aggregation, Deposition, and Adhesion Force Measurement

    KAUST Repository

    Gutierrez, Leonardo

    2012-08-21

    Interactions between rotavirus and Suwannee River natural organic matter (NOM) were studied by time-resolved dynamic light scattering, quartz crystal microbalance, and atomic force microscopy. In NOM-containing NaCl solutions of up to 600 mM, rotavirus suspension remained stable for over 4 h. Atomic force microscopy (AFM) measurement for interaction force decay length at different ionic strengths showed that nonelectrostatic repulsive forces were mainly responsible for eliminating aggregation in NaCl solutions. Aggregation rates of rotavirus in solutions containing 20 mg C/L increased with divalent cation concentration until reaching a critical coagulation concentration of 30 mM CaCl2 or 70 mM MgCl2. Deposition kinetics of rotavirus on NOM-coated silica surface was studied using quartz crystal microbalance. Experimental attachment efficiencies for rotavirus adsorption to NOM-coated surface in MgCl2 solution were lower than in CaCl2 solution at a given divalent cation concentration. Stronger adhesion force was measured for virus-virus and virus-NOM interactions in CaCl2 solution compared to those in MgCl2 or NaCl solutions at the same ionic strength. This study suggested that divalent cation complexation with carboxylate groups in NOM and on virus surface was an important mechanism in the deposition and aggregation kinetics of rotavirus. © 2012 American Chemical Society.

  2. Measuring Single-Bond Rupture Forces Using High Electric Fields in Microfluidic Channels and DNA Oligomers as Force Tags

    OpenAIRE

    Breisch, Stefanie; Gonska, Julian; Deissler, Helmut; Stelzle, Martin

    2005-01-01

    The disruption force of specific biotin-streptavidin bonds was determined using DNA oligomers as force tags. Forces were generated by an electric field acting on a biotinylated fluorescently labeled DNA oligomer. DNA oligomers were immobilized via biotin-streptavidin bonds on the walls of microfluidic channels. Channel layout and fluid-based deposition process were designed to enable well-defined localized deposition of the oligomers in a narrow gap of the microchannel. Electric fields of up ...

  3. The reliability of linear position transducer and force plate measurement of explosive force-time variables during a loaded jump squat in elite athletes.

    Science.gov (United States)

    Hansen, Keir T; Cronin, John B; Newton, Michael J

    2011-05-01

    The best method of assessing muscular force qualities during isoinertial stretch shorten cycle lower body movements remains a subject of much debate. This study had 2 purposes: Firstly, to calculate the interday reliability of peak force (PF) measurement and a variety of force-time measures, and, secondly, to compare the reliability of the 2 most common technologies for measuring force during loaded jump squats, the linear position transducer (PT), and the force plate (FP). Twenty-five male elite level rugby union players performed 3 rebound jump squats with a 40-kg external load on 2 occasions 1 week apart. Vertical ground reaction forces (GRFs) were directly measured via an FP, and force was differentiated from position data collected using a PT. From these data, a number of force-time variables were calculated for both the FP and PT. Intraclass correlation coefficient (ICC), coefficient of variation (CV), and percent change in the mean were used as measures of between-session reliability. Additionally, Pearson's product moment correlation coefficients were used to investigate intercorrelations between variables and technologies. Both FP and PT were found to be a reliable means of measuring PF (ICC = 0.88-0.96, CV = 2.3-4.8%), and the relationship between the 2 technologies was very high and high for days 1 and 2, respectively (r = 0.67-0.88). Force-time variables calculated from FP data tended to have greater relative and absolute consistency (ICC = 0.70-0.96, CV = 5.1-51.8%) than those calculated from differentiated PT data (ICC = 0.18-0.95, CV = 7.7-93.6%). Intercorrelations between variables ranged from trivial to practically perfect (r = 0.00-1.00). It was concluded that PF can be measured reliably with both FP and PT technologies, and these measurements are related. A number of force-time values can also be reliably calculated via the use of GRF data. Although some of these force-time variables can be reliably calculated using position data, variation of

  4. Simultaneous atomic force microscopy measurement of topography and contact resistance of metal films and carbon nanotubes

    International Nuclear Information System (INIS)

    Stadermann, M.; Grube, H.; Boland, J.J.; Papadakis, S.J.; Falvo, M.R.; Superfine, R.; Washburn, S.

    2003-01-01

    We present a quartz tuning-fork-based atomic force microscopy (AFM) setup that is capable of mapping the surface contact resistance while scanning topography. The tuning-fork setup allows us to use etched Pt/Ir tips, which have higher durability and better conductivity than probes used in earlier AFM conductance measurements. The performance of the method is demonstrated with contact resistance measurements of gold lines on silicon dioxide and carbon nanotubes on graphite

  5. Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength

    OpenAIRE

    Schans, van der, C.P.; Zijlstra, W.; Regterschot, G.R.H.; Krijnen, W.P.; Douma, K.W.; Slager, G.E.C.

    2016-01-01

    BACKGROUND: The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various d...

  6. Measuring system and method of determining the Adaptive Force

    Directory of Open Access Journals (Sweden)

    Laura Schaefer

    2017-07-01

    Full Text Available The term Adaptive Force (AF describes the capability of adaptation of the nerve-muscle-system to externally applied forces during isometric and eccentric muscle action. This ability plays an important role in real life motions as well as in sports. The focus of this paper is on the specific measurement method of this neuromuscular action, which can be seen as innovative. A measuring system based on the use of compressed air was constructed and evaluated for this neuromuscular function. It depends on the physical conditions of the subject, at which force level it deviates from the quasi isometric position and merges into eccentric muscle action. The device enables – in contrast to the isokinetic systems – a measure of strength without forced motion. Evaluation of the scientific quality criteria of the devices was done by measurements regarding the intra- and interrater-, the test-retest-reliability and fatiguing measurements. Comparisons of the pneumatic device with a dynamometer were also done. Looking at the mechanical evaluation, the results show a high level of consistency (r²=0.94 to 0.96. The parallel test reliability delivers a very high and significant correlation (ρ=0.976; p=0.000. Including the biological system, the concordance of three different raters is very high (p=0.001, Cronbachs alpha α=0.987. The test retest with 4 subjects over five weeks speaks for the reliability of the device in showing no statistically significant differences. These evaluations indicate that the scientific evaluation criteria are fulfilled. The specific feature of this system is that an isometric position can be maintained while the externally impacting force rises. Moreover, the device can capture concentric, static and eccentric strength values. Fields of application are performance diagnostics in sports and medicine.

  7. Measurement of the Young’s modulus using micro-cantilevered beam actuated by electrostatic force

    Science.gov (United States)

    Wang, Zhichong; Zhang, Qichang; Wang, Chen

    2018-02-01

    Determining the Young’s modulus accurately is important in micro-electro-mechanical systems (MEMS) design. Generally, the Young’s modulus of a micro-component is measured by the resonance method, of which the actuation is electrostatic force. However, this method does not take the effect of the electrostatic force on the resonant frequency into consideration. Thus, the test error becomes more obvious as the DC voltage increases. In this paper, an improved resonance method, determining the Young’s modulus of a micro-cantilever beam, is proposed, which takes the nonlinearity of the electrostatic force into consideration. This method has three obvious advantages: only one simple micro-cantilevered beam sample is needed; it is unnecessary to find the initial thickness of the gas film between the beam and the substrate; the accuracy of the measurement result of the Young’s modulus is improved. In order to obtain the resonant frequency of a cantilevered beam actuated by a DC voltage, the dynamic equations of the micro-cantilevered beam in multi-field coupled situations are established, and the effect of the electrostatic force on the resonant frequency of the micro-beam is investigated. Results show that, the Young’s modulus can be found by measuring the resonant frequency and DC voltage. The dynamics performances of the micro-structure are influenced by the nonlinearity of the electrostatic force, and the electrostatic effect should be observed especially when the beam becomes smaller, through general studies. Finally, the experimental principle of measuring the Young’s modulus is designed and conducted to verify these theories. The Young’s modulus of brass is measured exactly.

  8. Reliability of the Q Force; a mobile instrument for measuring isometric quadriceps muscle strength.

    Science.gov (United States)

    Douma, K W; Regterschot, G R H; Krijnen, W P; Slager, G E C; van der Schans, C P; Zijlstra, W

    2016-01-01

    The ability to generate muscle strength is a pre-requisite for all human movement. Decreased quadriceps muscle strength is frequently observed in older adults and is associated with a decreased performance and activity limitations. To quantify the quadriceps muscle strength and to monitor changes over time, instruments and procedures with a sufficient reliability are needed. The Q Force is an innovative mobile muscle strength measurement instrument suitable to measure in various degrees of extension. Measurements between 110 and 130° extension present the highest values and the most significant increase after training. The objective of this study is to determine the test-retest reliability of muscle strength measurements by the Q Force in older adults in 110° extension. Forty-one healthy older adults, 13 males and 28 females were included in the study. Mean (SD) age was 81.9 (4.89) years. Isometric muscle strength of the Quadriceps muscle was assessed with the Q Force at 110° of knee extension. Participants were measured at two sessions with a three to eight day interval between sessions. To determine relative reliability, the intraclass correlation coefficient (ICC) was calculated. To determine absolute reliability, Bland and Altman Limits of Agreement (LOA) were calculated and t-tests were performed. Relative reliability of the Q Force is good to excellent as all ICC coefficients are higher than 0.75. Generally a large 95 % LOA, reflecting only moderate absolute reliability, is found as exemplified for the peak torque left leg of -18.6 N to 33.8 N and the right leg of -9.2 N to 26.4 N was between 15.7 and 23.6 Newton representing 25.2 % to 39.9 % of the size of the mean. Small systematic differences in mean were found between measurement session 1 and 2. The present study shows that the Q Force has excellent relative test-retest reliability, but limited absolute test-retest reliability. Since the Q Force is relatively cheap and mobile it is suitable for

  9. Midinfrared absorption measured at a lambda/400 resolution with an atomic force microscope.

    Science.gov (United States)

    Houel, Julien; Homeyer, Estelle; Sauvage, Sébastien; Boucaud, Philippe; Dazzi, Alexandre; Prazeres, Rui; Ortéga, Jean-Michel

    2009-06-22

    Midinfrared absorption can be locally measured using a detection combining an atomic force microscope and a pulsed excitation. This is illustrated for the midinfrared bulk GaAs phonon absorption and for the midinfrared absorption of thin SiO(2) microdisks. We show that the signal given by the cantilever oscillation amplitude of the atomic force microscope follows the spectral dependence of the bulk material absorption. The absorption spatial resolution achieved with microdisks is around 50 nanometer for an optical excitation around 22 micrometer wavelength.

  10. Surface tension effect on the mechanical properties of nanomaterials measured by atomic force microscopy

    Science.gov (United States)

    Cuenot, Stéphane; Frétigny, Christian; Demoustier-Champagne, Sophie; Nysten, Bernard

    2004-04-01

    The effect of reduced size on the elastic properties measured on silver and lead nanowires and on polypyrrole nanotubes with an outer diameter ranging between 30 and 250 nm is presented and discussed. Resonant-contact atomic force microscopy (AFM) is used to measure their apparent elastic modulus. The measured modulus of the nanomaterials with smaller diameters is significantly higher than that of the larger ones. The latter is comparable to the macroscopic modulus of the materials. The increase of the apparent elastic modulus for the smaller diameters is attributed to surface tension effects. The surface tension of the probed material may be experimentally determined from these AFM measurements.

  11. Comparison of the bite mark pattern and intercanine distance between humans and dogs.

    Science.gov (United States)

    Kashyap, Bina; Anand, Sanjeev; Reddy, Sudhakara; Sahukar, Shruthi Basavaradhya; Supriya, Naga; Pasupuleti, Swetha

    2015-01-01

    Bite marks show uniqueness due to specific characteristics and arrangement of teeth, but when it comes to bite mark analysis, it is complicated by numerous factors such as animal bite, abuse etc., Humans and pet animals (dog) bite marks analysis is by far the most demanding and complicated part of forensic dentistry. To analyze and compare bite marks of humans and the pet animals (dog) using indirect method, so as to assess its usefulness and application in forensic odontology. 40 samples including 20 humans (10 males and 10 females) and 20 dogs of different breed were included in the study. Bite registration of all the samples were obtained on modeling wax and intercanine distance were measured. Data were analyzed and results were tabulated. Arch size and intercanine distance showed variable differences among humans and on average dogs showed more intercanine distance and arch size. Among dog breeds larger dogs showed larger variables when compared to smaller dogs. Assessment of bite marks evidences made by animals needs further investigation so that it can be a tool to assist the justice system to answer crucial questions.

  12. Afibrinogenemia following snake bite (Crotalus durissus terrificus

    Directory of Open Access Journals (Sweden)

    C. F. S. Amaral

    1988-08-01

    Full Text Available This paper reports two cases of afibrinogenemia with normal platelet count following Crotalus durissus terrificus, snake bite Both patients presented high output acute renal failure and case two also had increased blood levels of CPK and LDH compatible with the diagnosis of rhabdomyolysis. Case one was given an unknown amount of antivenom and was treated with epsilonaminocaproic acid and a fresh whole blood transfusion and showed recovery of the coagulation disturbance 40 hours following these measures. Case two was given an adequate amount of crotalide antivenom and the coagulation tests performed 12 hours later showed a normal partial thromboplastin time and fibrinogen 86 mg/100ml. Case one presented no haemorrhagic disturbances. Case two presented persistent bleeding following venopuncture and after removal of impetigo crust in the legs. Acute renal failure was treated conservatively and both patients were discharged from the hospital with recovery of the renal function.

  13. Injurious tail biting in pigs

    DEFF Research Database (Denmark)

    D'Eath, R.B.; Amott, G.; Turner, S. P.

    2014-01-01

    underlying processes of tail biting. A quantitative comparison of the efficacy of different methods of provision of manipulable materials, and a review of current practices in countries and assurance schemes where tail docking is banned, both suggest that daily provision of small quantities of destructible...... and prevention of tail damage. However, there is a lack of scientific studies on how best to respond to outbreaks: the effectiveness of, for example, removing biters and/or bitten pigs, increasing enrichment, or applying substances to tails should be investigated. Finally, some breeding companies are exploring...

  14. Surface force measurements at the basal planes of ordered kaolinite particles.

    Science.gov (United States)

    Gupta, Vishal; Miller, Jan D

    2010-04-15

    An experimental procedure is presented to order kaolinite particles on substrates for interrogation of the two basal plane surfaces by atomic force microscopy. Surface force measurements were performed between a silicon nitride tip and each of the two faces (silica tetrahedral face and alumina octahedral face) of kaolinite in 1 mM KCl solution at pH 4, 5, 6, 8 and 10, using atomic force microscopy. The colloidal force measurements reveal that the silica tetrahedral face of kaolinite is negatively charged at pH>4, whereas the alumina octahedral face of kaolinite is positively charged at pH8. Such measurements have not been reported previously and the results suggest that the iso-electric point of the silica tetrahedral face is at pHkaolinite carry a permanent negative charge due to minor substitution of Al(3+) for Si(4+) in the silica tetrahedral layer, and suggest some surface charge dependency of the two faces with respect to solution pH. With this new information it may be possible to further explain the electrokinetic behavior of kaolinite particles, and their interactions in aqueous suspensions. 2010 Elsevier Inc. All rights reserved.

  15. On electrostatic and Casimir force measurements between conducting surfaces in a sphere-plane configuration

    International Nuclear Information System (INIS)

    Kim, W J; Brown-Hayes, M; Brownell, J H; Dalvit, D A R; Onofrio, R

    2009-01-01

    We report on measurements of forces acting between two conducting surfaces in a spherical-plane configuration in the 35 nm-1 μm separation range. The measurements are obtained by performing electrostatic calibrations followed by a residuals analysis after subtracting the electrostatic-dependent component. We find in all runs optimal fitting of the calibrations for exponents smaller than the one predicted by electrostatics for an ideal sphere-plane geometry. We also find that the external bias potential necessary to minimize the electrostatic contribution depends on the sphere-plane distance. In spite of these anomalies, by implementing a parametrization-dependent subtraction of the electrostatic contribution we have found evidence for short-distance attractive forces of magnitude comparable to the expected Casimir-Lifshitz force. We finally discuss the relevance of our findings in the more general context of Casimir-Lifshitz force measurements, with particular regard to the critical issues of the electrical and geometrical characterization of the involved surfaces.

  16. Partnership for the Revitalization of National Wind Tunnel Force Measurement Capability

    Science.gov (United States)

    Rhew, Ray D.; Skelley, Marcus L.; Woike, Mark R.; Bader, Jon B.; Marshall, Timothy J.

    2009-01-01

    Lack of funding and lack of focus on research over the past several years, coupled with force measurement capabilities being decentralized and distributed across the National Aeronautics and Space Administration (NASA) research centers, has resulted in a significant erosion of (1) capability and infrastructure to produce and calibrate force measurement systems; (2) NASA s working knowledge of those systems; and (3) the quantity of high-quality, full-capability force measurement systems available for use in aeronautics testing. Simultaneously, and at proportional rates, the capability of industry to design, manufacture, and calibrate these test instruments has been eroding primarily because of a lack of investment by the aeronautics community. Technical expertise in this technology area is a core competency in aeronautics testing; it is highly specialized and experience-based, and it represents a niche market for only a few small precision instrument shops in the United States. With this backdrop, NASA s Aeronautics Test Program (ATP) chartered a team to examine the issues and risks associated with the problem, focusing specifically on strain- gage balances. The team partnered with the U.S. Air Force s Arnold Engineering Development Center (AEDC) to exploit their combined capabilities and take a national level government view of the problem. This paper describes the team s approach, its findings, and its recommendations, and the current status for revitalizing the government s balance capability with respect to designing, fabricating, calibrating, and using the instruments.

  17. Stress-strain relationship of PDMS micropillar for force measurement application

    Science.gov (United States)

    Johari, Shazlina; Shyan, L. Y.

    2017-11-01

    There is an increasing interest to use polydimethylsiloxane (PDMS) based materials as bio-transducers for force measurements in the order of micro to nano Newton. The accuracy of these devices relies on appropriate material characterization of PDMS and modelling to convert the micropillar deformations into the corresponding forces. Previously, we have reported on fabricated PDMS micropillar that acts as a cylindrical cantilever and was experimentally used to measure the force of the nematode C. elegans. In this research, similar PDMS micropillars are designed and simulated using ANSYS software. The simulation involves investigating two main factors that is expected to affect the force measurement performance; pillar height and diameter. Results show that the deformation increases when pillar height is increased and the deformation is inversely proportional to the pillar diameter. The maximum deformation obtained is 713 um with pillar diameter of 20 um and pillar height of 100 um. Results of stress and strain show similar pattern, where their values decreases as pillar diameter and height is increased. The simulated results are also compared with the calculated displacement. The trend for both calculated and simulated values are similar with 13% average difference.

  18. Stress-strain relationship of PDMS micropillar for force measurement application

    Directory of Open Access Journals (Sweden)

    Johari Shazlina

    2017-01-01

    Full Text Available There is an increasing interest to use polydimethylsiloxane (PDMS based materials as bio-transducers for force measurements in the order of micro to nano Newton. The accuracy of these devices relies on appropriate material characterization of PDMS and modelling to convert the micropillar deformations into the corresponding forces. Previously, we have reported on fabricated PDMS micropillar that acts as a cylindrical cantilever and was experimentally used to measure the force of the nematode C. elegans. In this research, similar PDMS micropillars are designed and simulated using ANSYS software. The simulation involves investigating two main factors that is expected to affect the force measurement performance; pillar height and diameter. Results show that the deformation increases when pillar height is increased and the deformation is inversely proportional to the pillar diameter. The maximum deformation obtained is 713 um with pillar diameter of 20 um and pillar height of 100 um. Results of stress and strain show similar pattern, where their values decreases as pillar diameter and height is increased. The simulated results are also compared with the calculated displacement. The trend for both calculated and simulated values are similar with 13% average difference.

  19. Measuring graphene adhesion using atomic force microscopy with a microsphere tip

    Science.gov (United States)

    Jiang, Tao; Zhu, Yong

    2015-06-01

    Van der Waals adhesion between graphene and various substrates has an important impact on the physical properties, device applications and nanomanufacturing processes of graphene. Here we report a general, high-throughput and reliable method that can measure adhesion energies between ultraflat graphene and a broad range of materials using atomic force microscopy with a microsphere tip. In our experiments, only van der Waals force between the tip and a graphene flake is measured. The Maugis-Dugdale theory is employed to convert the measured adhesion force using AFM to the adhesion energy. The ultraflatness of monolayer graphene on mica eliminates the effect of graphene surface roughness on the adhesion, while roughness of the microsphere tip is addressed by the modified Rumpf model. Adhesion energies of monolayer graphene to SiO2 and Cu are obtained as 0.46 and 0.75 J m-2, respectively. This work provides valuable insight into the mechanism of graphene adhesion and can readily extend to the adhesion measurement for other 2D nanomaterials.Van der Waals adhesion between graphene and various substrates has an important impact on the physical properties, device applications and nanomanufacturing processes of graphene. Here we report a general, high-throughput and reliable method that can measure adhesion energies between ultraflat graphene and a broad range of materials using atomic force microscopy with a microsphere tip. In our experiments, only van der Waals force between the tip and a graphene flake is measured. The Maugis-Dugdale theory is employed to convert the measured adhesion force using AFM to the adhesion energy. The ultraflatness of monolayer graphene on mica eliminates the effect of graphene surface roughness on the adhesion, while roughness of the microsphere tip is addressed by the modified Rumpf model. Adhesion energies of monolayer graphene to SiO2 and Cu are obtained as 0.46 and 0.75 J m-2, respectively. This work provides valuable insight into the

  20. Talking to Patients about Preventing Tick Bites

    Centers for Disease Control (CDC) Podcasts

    2012-02-14

    This podcast will help health care providers identify patients who are at increased risk of getting tick bites and provide these patients with tick bite prevention and removal tips.  Created: 2/14/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/14/2012.

  1. Functional Analysis and Treatment of Nail Biting

    Science.gov (United States)

    Dufrene, Brad A.; Watson, T. Steuart; Kazmerski, Jennifer S.

    2008-01-01

    This study applied functional analysis methodology to nail biting exhibited by a 24-year-old female graduate student. Results from the brief functional analysis indicated variability in nail biting across assessment conditions. Functional analysis data were then used to guide treatment development and implementation. Treatment included a…

  2. A Scheme for Solving the Plane–Plane Challenge in Force Measurements at the Nanoscale

    Directory of Open Access Journals (Sweden)

    Comin Fabio

    2010-01-01

    Full Text Available Abstract Non-contact interaction between two parallel flat surfaces is a central paradigm in sciences. This situation is the starting point for a wealth of different models: the capacitor description in electrostatics, hydrodynamic flow, thermal exchange, the Casimir force, direct contact study, third body confinement such as liquids or films of soft condensed matter. The control of parallelism is so demanding that no versatile single force machine in this geometry has been proposed so far. Using a combination of nanopositioning based on inertial motors, of microcrystal shaping with a focused-ion beam (FIB and of accurate in situ and real-time control of surface parallelism with X-ray diffraction, we propose here a “gedanken” surface-force machine that should enable one to measure interactions between movable surfaces separated by gaps in the micrometer and nanometer ranges.

  3. A scheme for solving the plane-plane challenge in force measurements at the nanoscale.

    Science.gov (United States)

    Siria, Alessandro; Huant, Serge; Auvert, Geoffroy; Comin, Fabio; Chevrier, Joel

    2010-05-19

    Non-contact interaction between two parallel flat surfaces is a central paradigm in sciences. This situation is the starting point for a wealth of different models: the capacitor description in electrostatics, hydrodynamic flow, thermal exchange, the Casimir force, direct contact study, third body confinement such as liquids or films of soft condensed matter. The control of parallelism is so demanding that no versatile single force machine in this geometry has been proposed so far. Using a combination of nanopositioning based on inertial motors, of microcrystal shaping with a focused-ion beam (FIB) and of accurate in situ and real-time control of surface parallelism with X-ray diffraction, we propose here a "gedanken" surface-force machine that should enable one to measure interactions between movable surfaces separated by gaps in the micrometer and nanometer ranges.

  4. Aerodynamic Characterization of ‘DelFly Micro’ in Forward Flight Configuration by Force Measurements and Flow Field Visualization

    OpenAIRE

    Deng, Shuanghou; Percin, Mustafa; van Oudheusden, Bas

    2015-01-01

    This study explores the flow structures and unsteady force generation mechanisms of a flapping-wing micro air vehicle ‘DelFly Micro’ in forward flight configuration. Stereoscopic Particle Image Velocimetry (Stereo-PIV) measurements were performed to acquire three dimensional flow fields in the wake. Six components of forces and moments were captured simultaneously by use of a miniature force sensor.

  5. A force measurement system based on an electrostatic sensing and actuating technique for calibrating force in a micronewton range with a resolution of nanonewton scale

    International Nuclear Information System (INIS)

    Chen, Sheng-Jui; Pan, Sheau-Shi

    2011-01-01

    This paper introduces a force measurement system recently established at the Center for Measurement Standards, Industrial Technology Research Institute for calibrating forces in a micronewton range with a resolution of a few nanonewtons. The force balance consists of a monolithic flexure stage and a specially made capacitor for electrostatic sensing and actuating. The capacitor is formed by three electrodes which can be utilized as a capacitive position sensor and an electrostatic force actuator at the same time. Force balance control is implemented with a digital controller by which the signal of the stage deflection is acquired, filtered and fed back to the electrostatic force driver to bring the flexure stage to the null position. The detailed description of the apparatus including the design of a monolithic flexure stage, principle of capacitive position sensing/electrostatic actuation and the force balance control is given in the paper. Finally, we present the results of electrostatic force calibration and the weighing of a 1 mg wire weight

  6. Estimation of clamping force in high-tension bolts through ultrasonic velocity measurement.

    Science.gov (United States)

    Jhang, Kyung-Young; Quan, Hai-Hua; Ha, Job; Kim, Noh-Yu

    2006-12-22

    The estimation of clamping force has been regarded as the main issue in the maintenance of high-tension bolts. This paper proposes a method which uses the dependency of ultrasonic velocity on stress based on the nonlinear elastic effect. The variation of ultrasonic velocity in the range of actual stress acting in the bolt is very small so that the precise measurement of ultrasonic velocity is needed. In this paper, we adopt a method to measure ultrasonic velocity, where the TOF (time of flight) of a tone-burst ultrasonic wave is precisely measured by using the phase detection technique. In order to verify the usefulness of the proposed method, two kinds of experiments are carried out. The first one measures ultrasonic velocity when the bolt is stressed by the tension tester, and from this, the exact axial force acting in the bolt can be determined. The results show good agreement with the expected linear relationship between ultrasonic velocity and axial stress. The second experiment measures ultrasonic velocity when the bolt is stressed by the torque wrench. The results show that ultrasonic velocity decreased as the torque increased, which is identical to the theoretically expected tendency. From these results, it can be said that the proposed method is adequate in evaluating clamping force in high-tension bolts.

  7. Real-time measurement of needle forces and acute pressure changes during intravitreal injections.

    Science.gov (United States)

    Christensen, Logan; Cerda, Ashlee; Olson, Jeffrey L

    2017-11-01

    The purpose of this study was to use a physiological pressure transducer to measure real-time, continuous pressure changes in an ex vivo study model of porcine eyes to record the amount of force needed for scleral penetration and to measure acute intraocular pressure rise during intravitreal injections. A pressure transducer was inserted into the anterior chamber of 30 fresh porcine eyes, and intraocular pressure was measured 2 s prior to intravitreal injection until 2 s after. A force transducer plate was used to insert various gauge needles into the vitreous cavity and the amount of force in Newtons (N) required for scleral penetration was recorded. For scleral perforation, 32- and 30-gauge needles required 0.44 N and 0.45 N, significantly less than larger gauge needles (P time continuous recordings of pressure reveal that an instantaneous intraocular pressure spike occurs during intravitreal injection and appears to be separate from the intraocular pressure spike that occurs during needle insertion. This pressure spike is transient and has not been captured by previous methods of intraocular pressure measurement, which rely on single time point measurements. The clinical significance of this brief intraocular pressure spike is unclear and warrants further investigation. © 2017 Royal Australian and New Zealand College of Ophthalmologists.

  8. Kinetic analysis of ski turns based on measured ground reaction forces.

    Science.gov (United States)

    Vaverka, Frantisek; Vodickova, Sona; Elfmark, Milan

    2012-02-01

    The objective of this study was to devise a method of kinetic analysis of the ground reaction force that enables the durations and magnitudes of forces acting during the individual phases of ski turns to be described exactly. The method is based on a theoretical analysis of physical forces acting during the ski turn. Two elementary phases were defined: (1) preparing to turn (initiation) and (2) actual turning, during which the center of gravity of the skier-ski system moves along a curvilinear trajectory (steering). The starting point of the turn analysis is a dynamometric record of the resultant acting ground reaction force applied perpendicularly on the ski surface. The method was applied to six expert skiers. They completed a slalom course comprising five gates arranged on the fall line of a 26° slope at a competition speed using symmetrical carving turns (30 evaluated turns). A dynamometric measurement system was placed on the carving skis (168 cm long, radius 16 m, data were recorded at 100 Hz). MATLAB procedures were used to evaluate eight variables during each turn: five time variables and three force variables. Comparison of the turn analysis results between individuals showed that the method is useful for answering various research questions associated with ski turns.

  9. Tick Bite Alopecia: A Report and Review.

    Science.gov (United States)

    Lynch, Michael C; Milchak, Marissa A; Parnes, Herbert; Ioffreda, Michael D

    2016-11-01

    Tick bites can cause a number of local inflammatory reactions, which are often difficult to differentiate from those induced by other arthropod bites or stings. These include erythematous nodular or pustular lesions, erosive plaques, annular lesions of erythema chronicum migrans, and both scarring and nonscarring inflammatory alopecia. We report a case of nonscarring alopecia in a 21-year-old male who reported a recent history of tick bite to the scalp. The biopsy demonstrated a dense pseudolymphomatous inflammatory infiltrate with numerous eosinophils associated with hair follicle miniaturization and an elevated catagen-telogen count. Signs of external rubbing, including lichen simplex chronicus and the "hamburger sign", were also visualized and are indicative of the associated pruritus. To the authors' knowledge, this is the fifth report of nonscarring tick bite alopecia in the literature and the first in an adult patient. This text will review the classic clinical presentation, histologic findings, and proposed mechanism of tick bite alopecia.

  10. Iguana bites reported to Texas poison centers.

    Science.gov (United States)

    Forrester, Mathias B

    2010-09-01

    Although thousands of iguanas are kept as pets in the United States, information on their bites is limited. The intent of this investigation was to describe the pattern of iguana bites reported to Texas poison centers. Iguana bites reported during 1998-2008 were identified. The distribution of cases by various factors was determined. Of 59 total bites, 71% were managed on-site, 17% of the patients were at or en route to a health care facility when the poison center was contacted, and 10% were referred to a health care facility. The medical outcome was no effect in 9% of the cases, minor effect in 24%, moderate effect in 2%, not followed but minimal effects possible in 64%, and unable to follow but potentially toxic in 2%. Most iguana bites reported to Texas poison centers did not result in serious effects and were managed on-site. Copyright © 2010 Elsevier Inc. All rights reserved.

  11. Preliminarily measurement and analysis of sawing forces in fresh cadaver mandible using reciprocating saw for reality-based haptic feedback.

    Science.gov (United States)

    Yua, Dedong; Zhengb, Xiaohu; Chenc, Ming; Shend, Steve G F

    2012-05-01

    The aim of the study was to preliminarily measure and analyze the cutting forces in fresh Chinese cadaver mandible using a clinically widely used reciprocating saw for reality-based haptic feedback. Eight mandibles were taken from fresh Chinese cadavers, 4 females and 4 males, aged between 59 and 95 years. A set of sawing experiments, using a surgery Stryker micro-reciprocating saw and Kistler piezoelectric dynamometer, was carried out by a CNC machining center. Under different vibration frequencies of saw and feeding rates measured from orthognathic surgery, sawing forces were recorded by a signal acquisition system. Remarkably different sawing forces were measured from different cadavers. Feed and vibration frequency of the reciprocating saw could determine the cutting forces only on 1 body. To reduce the impact of bone thickness changes on the cutting force measurements, all the cutting force data should be converted to the force of unit cutting length. The vibration frequency of haptic feedback system is determined by main cutting forces. Fast Fourier transform method can be used to calculate the frequency of this system. To simulate surgery in higher fidelity, all the sawing forces from the experiment should be amended by experienced surgeons before use in virtual reality surgery simulator. Sawing force signals of different ages for force feedback were measured successfully, and more factors related to the bone mechanical properties, such as bone density, should be concerned in the future.

  12. Integrated magnetic and elastic force systems.

    Science.gov (United States)

    Bourauel, Christoph; Köklü, Saduman O; Vardimon, Alexander D

    2002-08-01

    Magnetic force increases as the distance (d) of the force- generating elements (F approximately 1/d(2)) decreases, whereas elastic force decreases as the distance decreases (F approximately kd). These opposing characteristics suggest that combining both force systems will establish an integrated system with a long-range working ability. The objective of this study was to determine the vertical closure force (F(X)) and the transverse axis moment (M(Y)) of an integrated force system, ie, attracting magnets with elastics (vertical or Classes II and III). F(X) and M(Y) were examined on the orthodontic measurement and simulation system. It was found that the integrated force system had a positive closure force (+F(X)) that never declined to 0 and a long working range. Three regions characterized the force-deflection curve of F(X): the magnetic region (0-3 mm, for magnets with 3/16-in medium elastics), in which the decline in magnetic force was larger than the increase in elastic force (6.3-2.5 N); the constant region (3-7 mm), in which the decline in magnetic force equaled the increase in elastic force (2.5-2.9 N); and the elastic region (7-10 mm), in which there was only an increase in elastic force (2.9-3.5 N). The transverse axis moment (+M(Y)), which tends to close the bite, developed especially in magnets with a single vertical elastic. Clinically, inactivation of vertical elastics by closing the mouth can be overruled by the integrated force system because it exerts adequate force level at both short and long distances.

  13. Acquisition and deconvolution of seismic signals by different methods to perform direct ground-force measurements

    Science.gov (United States)

    Poletto, Flavio; Schleifer, Andrea; Zgauc, Franco; Meneghini, Fabio; Petronio, Lorenzo

    2016-12-01

    We present the results of a novel borehole-seismic experiment in which we used different types of onshore-transient-impulsive and non-impulsive-surface sources together with direct ground-force recordings. The ground-force signals were obtained by baseplate load cells located beneath the sources, and by buried soil-stress sensors installed in the very shallow-subsurface together with accelerometers. The aim was to characterize the source's emission by its complex impedance, function of the near-field vibrations and soil stress components, and above all to obtain appropriate deconvolution operators to remove the signature of the sources in the far-field seismic signals. The data analysis shows the differences in the reference measurements utilized to deconvolve the source signature. As downgoing waves, we process the signals of vertical seismic profiles (VSP) recorded in the far-field approximation by an array of permanent geophones cemented at shallow-medium depth outside the casing of an instrumented well. We obtain a significant improvement in the waveform of the radiated seismic-vibrator signals deconvolved by ground force, similar to that of the seismograms generated by the impulsive sources, and demonstrates that the results obtained by different sources present low values in their repeatability norm. The comparison evidences the potentiality of the direct ground-force measurement approach to effectively remove the far-field source signature in VSP onshore data, and to increase the performance of permanent acquisition installations for time-lapse application purposes.

  14. Non-additivity of molecule-surface van der Waals potentials from force measurements

    Science.gov (United States)

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G.; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F. Stefan

    2014-11-01

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  15. Non-additivity of molecule-surface van der Waals potentials from force measurements.

    Science.gov (United States)

    Wagner, Christian; Fournier, Norman; Ruiz, Victor G; Li, Chen; Müllen, Klaus; Rohlfing, Michael; Tkatchenko, Alexandre; Temirov, Ruslan; Tautz, F Stefan

    2014-11-26

    Van der Waals (vdW) forces act ubiquitously in condensed matter. Despite being weak on an atomic level, they substantially influence molecular and biological systems due to their long range and system-size scaling. The difficulty to isolate and measure vdW forces on a single-molecule level causes our present understanding to be strongly theory based. Here we show measurements of the attractive potential between differently sized organic molecules and a metal surface using an atomic force microscope. Our choice of molecules and the large molecule-surface separation cause this attraction to be purely of vdW type. The experiment allows testing the asymptotic vdW force law and its validity range. We find a superlinear growth of the vdW attraction with molecular size, originating from the increased deconfinement of electrons in the molecules. Because such non-additive vdW contributions are not accounted for in most first-principles or empirical calculations, we suggest further development in that direction.

  16. Merging Psychophysical and Psychometric Theory to Estimate Global Visual State Measures from Forced-Choices

    International Nuclear Information System (INIS)

    Massof, Robert W; Schmidt, Karen M; Laby, Daniel M; Kirschen, David; Meadows, David

    2013-01-01

    Visual acuity, a forced-choice psychophysical measure of visual spatial resolution, is the sine qua non of clinical visual impairment testing in ophthalmology and optometry patients with visual system disorders ranging from refractive error to retinal, optic nerve, or central visual system pathology. Visual acuity measures are standardized against a norm, but it is well known that visual acuity depends on a variety of stimulus parameters, including contrast and exposure duration. This paper asks if it is possible to estimate a single global visual state measure from visual acuity measures as a function of stimulus parameters that can represent the patient's overall visual health state with a single variable. Psychophysical theory (at the sensory level) and psychometric theory (at the decision level) are merged to identify the conditions that must be satisfied to derive a global visual state measure from parameterised visual acuity measures. A global visual state measurement model is developed and tested with forced-choice visual acuity measures from 116 subjects with no visual impairments and 560 subjects with uncorrected refractive error. The results are in agreement with the expectations of the model

  17. Merging Psychophysical and Psychometric Theory to Estimate Global Visual State Measures from Forced-Choices

    Science.gov (United States)

    Massof, Robert W.; Schmidt, Karen M.; Laby, Daniel M.; Kirschen, David; Meadows, David

    2013-09-01

    Visual acuity, a forced-choice psychophysical measure of visual spatial resolution, is the sine qua non of clinical visual impairment testing in ophthalmology and optometry patients with visual system disorders ranging from refractive error to retinal, optic nerve, or central visual system pathology. Visual acuity measures are standardized against a norm, but it is well known that visual acuity depends on a variety of stimulus parameters, including contrast and exposure duration. This paper asks if it is possible to estimate a single global visual state measure from visual acuity measures as a function of stimulus parameters that can represent the patient's overall visual health state with a single variable. Psychophysical theory (at the sensory level) and psychometric theory (at the decision level) are merged to identify the conditions that must be satisfied to derive a global visual state measure from parameterised visual acuity measures. A global visual state measurement model is developed and tested with forced-choice visual acuity measures from 116 subjects with no visual impairments and 560 subjects with uncorrected refractive error. The results are in agreement with the expectations of the model.

  18. The role of the cantilever in Kelvin probe force microscopy measurements

    Directory of Open Access Journals (Sweden)

    George Elias

    2011-05-01

    Full Text Available The role of the cantilever in quantitative Kelvin probe force microscopy (KPFM is rigorously analyzed. We use the boundary element method to calculate the point spread function of the measuring probe: Tip and cantilever. The calculations show that the cantilever has a very strong effect on the absolute value of the measured contact potential difference even under ultra-high vacuum conditions, and we demonstrate a good agreement between our model and KPFM measurements in ultra-high vacuum of NaCl monolayers grown on Cu(111. The effect of the oscillating cantilever shape on the KPFM resolution and sensitivity has been calculated and found to be relatively small.

  19. Force chains in monodisperse spherical particle assemblies: Three-dimensional measurements using neutrons

    Science.gov (United States)

    Wensrich, C. M.; Kisi, E. H.; Luzin, V.; Garbe, U.; Kirstein, O.; Smith, A. L.; Zhang, J. F.

    2014-10-01

    The full triaxial stress state within individual particles in a monodisperse spherical granular assembly has been measured. This was made possible by neutron imaging and computed tomography combined with neutron diffraction strain measurement techniques and associated stress reconstruction. The assembly in question consists of 549 precision steel ball bearings under an applied axial load of 85 MPa in a cylindrical die. Clear evidence of force chains was observed in terms of both the shape of the probability distribution function for normal stresses and the network formed by highly loaded particles. An extensive analysis of the source and magnitude of uncertainty in these measurements is also presented.

  20. Fluid force predictions and experimental measurements for a magnetically levitated pediatric ventricular assist device.

    Science.gov (United States)

    Throckmorton, Amy L; Untaroiu, Alexandrina; Lim, D Scott; Wood, Houston G; Allaire, Paul E

    2007-05-01

    The latest generation of artificial blood pumps incorporates the use of magnetic bearings to levitate the rotating component of the pump, the impeller. A magnetic suspension prevents the rotating impeller from contacting the internal surfaces of the pump and reduces regions of stagnant and high shear flow that surround fluid or mechanical bearings. Applying this third-generation technology, the Virginia Artificial Heart Institute has developed a ventricular assist device (VAD) to support infants and children. In consideration of the suspension design, the axial and radial fluid forces exerted on the rotor of the pediatric VAD were estimated using computational fluid dynamics (CFD) such that fluid perturbations would be counterbalanced. In addition, a prototype was built for experimental measurements of the axial fluid forces and estimations of the radial fluid forces during operation using a blood analog mixture. The axial fluid forces for a centered impeller position were found to range from 0.5 +/- 0.01 to 1 +/- 0.02 N in magnitude for 0.5 +/- 0.095 to 3.5 +/- 0.164 Lpm over rotational speeds of 6110 +/- 0.39 to 8030 +/- 0.57% rpm. The CFD predictions for the axial forces deviated from the experimental data by approximately 8.5% with a maximum difference of 18% at higher flow rates. Similarly for the off-centered impeller conditions, the maximum radial fluid force along the y-axis was found to be -0.57 +/- 0.17 N. The maximum cross-coupling force in the x direction was found to be larger with a maximum value of 0.74 +/- 0.22 N. This resulted in a 25-35% overestimate of the radial fluid force as compared to the CFD predictions; this overestimation will lead to a far more robust magnetic suspension design. The axial and radial forces estimated from the computational results are well within a range over which a compact magnetic suspension can compensate for flow perturbations. This study also serves as an effective and novel design methodology for blood pump

  1. A Polymer-Based Capacitive Sensing Array for Normal and Shear Force Measurement

    Science.gov (United States)

    Cheng, Ming-Yuan; Lin, Chun-Liang; Lai, Yu-Tse; Yang, Yao-Joe

    2010-01-01

    In this work, we present the development of a polymer-based capacitive sensing array. The proposed device is capable of measuring normal and shear forces, and can be easily realized by using micromachining techniques and flexible printed circuit board (FPCB) technologies. The sensing array consists of a polydimethlysiloxane (PDMS) structure and a FPCB. Each shear sensing element comprises four capacitive sensing cells arranged in a 2 × 2 array, and each capacitive sensing cell has two sensing electrodes and a common floating electrode. The sensing electrodes as well as the metal interconnect for signal scanning are implemented on the FPCB, while the floating electrodes are patterned on the PDMS structure. This design can effectively reduce the complexity of the capacitive structures, and thus makes the device highly manufacturable. The characteristics of the devices with different dimensions were measured and discussed. A scanning circuit was also designed and implemented. The measured maximum sensitivity is 1.67%/mN. The minimum resolvable force is 26 mN measured by the scanning circuit. The capacitance distributions induced by normal and shear forces were also successfully captured by the sensing array. PMID:22163466

  2. A Polymer-Based Capacitive Sensing Array for Normal and Shear Force Measurement

    Directory of Open Access Journals (Sweden)

    Ming-Yuan Cheng

    2010-11-01

    Full Text Available In this work, we present the development of a polymer-based capacitive sensing array. The proposed device is capable of measuring normal and shear forces, and can be easily realized by using micromachining techniques and flexible printed circuit board (FPCB technologies. The sensing array consists of a polydimethlysiloxane (PDMS structure and a FPCB. Each shear sensing element comprises four capacitive sensing cells arranged in a 2 × 2 array, and each capacitive sensing cell has two sensing electrodes and a common floating electrode. The sensing electrodes as well as the metal interconnect for signal scanning are implemented on the FPCB, while the floating electrodes are patterned on the PDMS structure. This design can effectively reduce the complexity of the capacitive structures, and thus makes the device highly manufacturable. The characteristics of the devices with different dimensions were measured and discussed. A scanning circuit was also designed and implemented. The measured maximum sensitivity is 1.67%/mN. The minimum resolvable force is 26 mN measured by the scanning circuit. The capacitance distributions induced by normal and shear forces were also successfully captured by the sensing array.

  3. Skeletal and Dentoalveolar Cephalometric Features of Anterior Open Bite among Yemeni Adults

    OpenAIRE

    Daer, Ammar Abdulkareem; Abuaffan, Amal Hussein

    2016-01-01

    Objective. The aim of this study is to determine the cephalometric features for a sample of Yemeni adults with anterior open bite. Material and Methods. Lateral cephalometric radiographs were taken for 65 Yemeni university students (46 males and 19 females), 18?25 years old, with clinical anterior open bite (vertical overbite ? 0?mm) and no previous orthodontic treatment. The radiographs were manually traced; twelve angular, five linear measurements, and facial index were assessed, analyzed s...

  4. Biting

    Science.gov (United States)

    ... get attention or express how they're feeling. Frustration, anger, and fear are strong emotions and toddlers ... in-progress, it's important to create a zero-tolerance culture at home, daycare, and elsewhere. Here are ...

  5. How to Measure Load-Dependent Kinetics of Individual Motor Molecules Without a Force-Clamp

    DEFF Research Database (Denmark)

    Sung, Jongmin; Mortensen, Kim; Spudich, James A.

    Molecular motors are responsible for numerous cellular processes from cargo transport to heart contraction. Their interactions with other cellular components are often transient and exhibit kinetics that depend on load. Here, we measure such interactions using a new method, Harmonic Force...... and efficient. The protocol accumulates statistics fast enough to deliver single-molecule results from single-molecule experiments. We demonstrate the method's performance by measuring the force-dependent kinetics of individual human beta-cardiac myosin molecules interacting with an actin filament...... at physiological ATP concentration. We show that a molecule's ADP release rate depends exponentially on the applied load. This points to Kramer's Brownian diffusion model of chemical reactions as explanation why muscle contracts with a velocity inversely proportional to external load....

  6. MEASUREMENTS OF SHOCK WAVE FORCE IN SHOCK TUBE WITH INDIRECT METHODS

    Directory of Open Access Journals (Sweden)

    Mario Dobrilović

    2005-12-01

    Full Text Available Tests have been conducted at the “Laboratory for testing of civil explosives, detonators, electrical detonators and pyrotechnical materials”, Department for mining and geotechnics of the Faculty of mining, geology and petroleum engineering, University of Zagreb with the purpose of designing a detonator that would unite advantages of a non-electric system and the precision in regulation of time delay in electronic initiation system. Sum of energy released by the wave force in shock tube is a pre-condition for operation of the new detonator, and measurement of wave force is the first step in determining the sum of energy. The sum of energy is measured indirectly, based on two principles: movement sensors and strain.

  7. Habitat use by mountain nyala Tragelaphus buxtoni determined using stem bite diameters at point of browse, bite rates, and time budgets in the Bale Mountains National Park, Ethiopia

    Directory of Open Access Journals (Sweden)

    Solomon A. TADESSE, Burt P. KOTLER

    2013-12-01

    Full Text Available We studied the habitat use of mountain nyala Tragelaphus buxtoni in the northern edge of the Bale Mountains National Park, Ethiopia. The aims of this study were to: (1 measure and quantify habitat-specific stem bite diameters of mountain nyala foraging on common natural plant species in two major habitat types (i.e. grasslands versus woodlands, and (2 quantify the bite rates (number of bites per minute and the activity time budgets of mountain nyala as functions of habitat type and sex-age category. We randomly laid out three transects in each habitat type. Following each transect, through focal animal observations, we assessed and quantified stem diameters at point of browse (dpb, bite rates, and time budgets of mountain nyala in grasslands versus woodlands. Stem dpb provide a measure of natural giving-up densities (GUDs and can be used to assess foraging costs and efficiencies, with greater stem dpb corresponding to lower costs and greater efficiencies. The results showed that stem dpb, bite rates, induced vigilance, and proportion of time spent in feeding differed between habitats. In particular, mountain nyala had greater stem dpb, higher bite rates, and spent a greater proportion of their time in feeding and less in induced vigilance in the grasslands. In addition, adult females had the highest bite rates, and the browse species Solanum marginatum had the greatest stem dpb. Generally, grasslands provide the mountain nyala with several advantages over the woodlands, including offering lower foraging costs, greater safety, and more time for foraging. The study advocates how behavioural indicators and natural GUDs are used to examine the habitat use of the endangered mountain nyala through applying non-invasive techniques. We conclude that the resulting measures are helpful for guiding conservation and management efforts and could be applicable to a number of endangered wildlife species including the mountain nyala [Current Zoology 59 (6 : 707

  8. Force measurements of flexible tandem wings in hovering and forward flights

    International Nuclear Information System (INIS)

    Zheng, Yingying; Wu, Yanhua; Tang, Hui

    2015-01-01

    Aerodynamic forces, power consumptions and efficiencies of flexible and rigid tandem wings undergoing combined plunging/pitching motion were measured in a hovering flight and two forward flights with Strouhal numbers of 0.6 and 0.3. Three flexible dragonfly-like tandem wing models termed Wing I, Wing II, and Wing III which are progressively less flexible, as well as a pair of rigid wings as the reference were operated at three phase differences of 0°, 90° and 180°. The results showed that both the flexibility and phase difference have significant effects on the aerodynamic performances. In both hovering and forward flights at a higher oscillation frequency of 1 Hz (St = 0.6), the Wing III model outperformed the other wing models with larger total horizontal force coefficient and efficiency. In forward flight at the lower frequency of 0.5 Hz (St = 0.3), Wing III, rigid wings and Wing II models performed best at 0°, 90° and 180° phase difference, respectively. From the time histories of force coefficients of fore- and hind-wings, different peak values, phase lags, and secondary peaks were found to be the important reasons to cause the differences in the average horizontal force coefficients. Particle image velocimetry and deformation measurements were performed to provide the insights into how the flexibility affects the aerodynamic performance of the tandem wings. The spanwise bending deformation was found to contribute to the horizontal force, by offering a more beneficial position to make LEV more attached to the wing model in both hovering and forward flights, and inducing a higher-velocity region in forward flight. (paper)

  9. Measurement-based aerosol forcing calculations: The influence of model complexity

    Directory of Open Access Journals (Sweden)

    Manfred Wendisch

    2001-03-01

    Full Text Available On the basis of ground-based microphysical and chemical aerosol measurements a simple 'two-layer-single-wavelength' and a complex 'multiple-layer-multiple-wavelength' radiative transfer model are used to calculate the local solar radiative forcing of black carbon (BC and (NH42SO4 (ammonium sulfate particles and mixtures (external and internal of both materials. The focal points of our approach are (a that the radiative forcing calculations are based on detailed aerosol measurements with special emphasis of particle absorption, and (b the results of the radiative forcing calculations with two different types of models (with regards to model complexity are compared using identical input data. The sensitivity of the radiative forcing due to key input parameters (type of particle mixture, particle growth due to humidity, surface albedo, solar zenith angle, boundary layer height is investigated. It is shown that the model results for external particle mixtures (wet and dry only slightly differ from those of the corresponding internal mixture. This conclusion is valid for the results of both model types and for both surface albedo scenarios considered (grass and snow. Furthermore, it is concluded that the results of the two model types approximately agree if it is assumed that the aerosol particles are composed of pure BC. As soon as a mainly scattering substance is included alone or in (internal or external mixture with BC, the differences between the radiative forcings of both models become significant. This discrepancy results from neglecting multiple scattering effects in the simple radiative transfer model.

  10. Adhesion force measurements on the two wax layers of the waxy zone in Nepenthes alata pitchers.

    Science.gov (United States)

    Gorb, Elena V; Purtov, Julia; Gorb, Stanislav N

    2014-06-03

    The wax coverage of the waxy zone in Nepenthes alata pitchers consists of two clearly distinguishable layers, designated the upper and lower wax layers. Since these layers were reported to reduce insect attachment, they were considered to have anti-adhesive properties. However, no reliable adhesion tests have been performed with these wax layers. In this study, pull-off force measurements were carried out on both wax layers of the N. alata pitcher and on two reference polymer surfaces using deformable polydimethylsiloxane half-spheres as probes. To explain the results obtained, roughness measurements were performed on test surfaces. Micro-morphology of both surface samples and probes tested was examined before and after experiments. Pull-off forces measured on the upper wax layer were the lowest among surfaces tested. Here, contamination of probes by wax crystals detached from the pitcher surface was found. This suggests that low insect attachment on the upper wax layer is caused primarily by the breaking off of wax crystals from the upper wax layer, which acts as a separation layer between the insect pad and the pitcher surface. High adhesion forces obtained on the lower wax layer are explained by the high deformability of probes and the particular roughness of the substrate.

  11. Constraints on axionlike particles and non-Newtonian gravity from measuring the difference of Casimir forces

    Science.gov (United States)

    Klimchitskaya, G. L.; Mostepanenko, V. M.

    2017-06-01

    We derive constraints on the coupling constants of axionlike particles to nucleons and on the Yukawa-type corrections to Newton's gravitational law from the results of recent experiment on measuring the difference of Casimir forces between a Ni-coated sphere and Au and Ni sectors of a structured disc. Over the wide range of axion masses from 2.61 meV to 0.9 eV the obtained constraints on the axion-to-nucleon coupling are up to a factor of 14.6 stronger than all previously known constraints following from experiments on measuring the Casimir interaction. The constraints on non-Newtonian gravity found here are also stronger than all that following from the Casimir- and Cavendish-type experiments over the interaction range from 30 nm to 5.4 μ m . They are up to a factor of 177 stronger than the constraints derived recently from measuring the difference of lateral forces. Our constraints confirm previous somewhat stronger limits obtained from the isoelectronic experiment, where the contribution of the Casimir force was nullified.

  12. Measurement of circulation around wing-tip vortices and estimation of lift forces using stereo PIV

    Science.gov (United States)

    Asano, Shinichiro; Sato, Haru; Sakakibara, Jun

    2017-11-01

    Applying the flapping flight to the development of an aircraft as Mars space probe and a small aircraft called MAV (Micro Air Vehicle) is considered. This is because Reynolds number assumed as the condition of these aircrafts is low and similar to of insects and small birds flapping on the earth. However, it is difficult to measure the flow around the airfoil in flapping flight directly because of its three-dimensional and unsteady characteristics. Hence, there is an attempt to estimate the flow field and aerodynamics by measuring the wake of the airfoil using PIV, for example the lift estimation method based on a wing-tip vortex. In this study, at the angle of attack including the angle after stall, we measured the wing-tip vortex of a NACA 0015 cross-sectional and rectangular planform airfoil using stereo PIV. The circulation of the wing-tip vortex was calculated from the obtained velocity field, and the lift force was estimated based on Kutta-Joukowski theorem. Then, the validity of this estimation method was examined by comparing the estimated lift force and the force balance data at various angles of attack. The experiment results are going to be presented in the conference.

  13. Molar heights and incisor inclinations in adults with Class II and Class III skeletal open-bite malocclusions.

    Science.gov (United States)

    Arriola-Guillén, Luis Ernesto; Flores-Mir, Carlos

    2014-03-01

    The aim of this research was to compare maxillary and mandibular molar heights and incisor inclinations in patients with skeletal open-bite Class II, patients with skeletal open-bite Class III, and an untreated control group. Pretreatment lateral cephalograms of 70 orthodontic patients (34 men, 36 women) between 16 and 40 years of age were examined. The sample was divided into 3 groups according to facial growth pattern and overbite. The control group (n = 25) included normodivergent Class I subjects with adequate overbite; the skeletal open-bite Class II group (n = 25) and the skeletal open-bite Class III group (n = 20) included hyperdivergent Class II or Class III subjects with negative overbite. Measurements considered were ANB angle, palatal and mandibular plane angles, maxillary incisor palatal plane angulation, and mandibular incisor mandibular plane angulation, as well as the distance from the palatal or the mandibular plane to the mesial cusp of the molars. Multivariate analysis of covariance and multivariate analysis of variance tests were used to determine the differences between the groups, followed by the Tukey post-hoc test. Additionally, the Mann-Whitney U test and Kruskall-Wallis test were performed. Significant differences in molar height were found (P open-bite and control groups was found. Mandibular molar height was greater in the skeletal open-bite Class II group (P open-bite Class III group by approximately 6°. Mandibular incisor to mandibular plane angulation was 10° more lingual in the skeletal open-bite Class III group (P open-bite groups had greater molar heights than did the control group. The skeletal open-bite Class II group had more eruption of the mandibular molars. The maxillary incisors were more proclined and the mandibular incisors were more lingual in the skeletal open-bite Class III group. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  14. Measurement correction method for force sensor used in dynamic pressure calibration based on artificial neural network optimized by genetic algorithm

    Science.gov (United States)

    Gu, Tingwei; Kong, Deren; Shang, Fei; Chen, Jing

    2017-12-01

    We present an optimization algorithm to obtain low-uncertainty dynamic pressure measurements from a force-transducer-based device. In this paper, the advantages and disadvantages of the methods that are commonly used to measure the propellant powder gas pressure, the applicable scope of dynamic pressure calibration devices, and the shortcomings of the traditional comparison calibration method based on the drop-weight device are firstly analysed in detail. Then, a dynamic calibration method for measuring pressure using a force sensor based on a drop-weight device is introduced. This method can effectively save time when many pressure sensors are calibrated simultaneously and extend the life of expensive reference sensors. However, the force sensor is installed between the drop-weight and the hammerhead by transition pieces through the connection mode of bolt fastening, which causes adverse effects such as additional pretightening and inertia forces. To solve these effects, the influence mechanisms of the pretightening force, the inertia force and other influence factors on the force measurement are theoretically analysed. Then a measurement correction method for the force measurement is proposed based on an artificial neural network optimized by a genetic algorithm. The training and testing data sets are obtained from calibration tests, and the selection criteria for the key parameters of the correction model is discussed. The evaluation results for the test data show that the correction model can effectively improve the force measurement accuracy of the force sensor. Compared with the traditional high-accuracy comparison calibration method, the percentage difference of the impact-force-based measurement is less than 0.6% and the relative uncertainty of the corrected force value is 1.95%, which can meet the requirements of engineering applications.

  15. Court presentation of bite mark evidence.

    Science.gov (United States)

    Drinnan, A J; Melton, M J

    1985-12-01

    The uniqueness of an individual's bite mark is generally accepted. The use of bite mark analysis to identify or exclude those suspected of crimes is now a well established activity in forensic dentistry. Although the techniques for evaluating bite mark evidence are extremely sophisticated, it is important that the courtroom presentation of such evidence should be as simple as possible and be directed towards those who must judge it. Dentists likely to be involved in the courtroom presentation of bite mark evidence should: be certain that their local law enforcement personnel are frequently updated on the techniques to be used for producing the optimum evidence needed to evaluate bite marks; become acquainted with the current techniques of evaluating bite mark evidence and understand their difficulties and pitfalls; meet with the lawyers (prosecution or defence) before a courtroom appearance, briefing them on the significance of the particular findings; prepare clear and easily understandable visual aids to present to the court the techniques used in the analysis and the bases for the conclusion reached; and offer conclusions derived from the bite mark investigation.

  16. Contrast enhancement of bite mark images using the grayscale mixer in ACR in Photoshop®.

    Science.gov (United States)

    Evans, Sam; Noorbhai, Suzanne; Lawson, Zoe; Stacey-Jones, Seren; Carabott, Romina

    2013-05-01

    Enhanced images may improve bite mark edge definition, assisting forensic analysis. Current contrast enhancement involves color extraction, viewing layered images by channel. A novel technique, producing a single enhanced image using the grayscale mix panel within Adobe Camera Raw®, has been developed and assessed here, allowing adjustments of multiple color channels simultaneously. Stage 1 measured RGB values in 72 versions of a color chart image; eight sliders in Photoshop® were adjusted at 25% intervals, all corresponding colors affected. Stage 2 used a bite mark image, and found only red, orange, and yellow sliders had discernable effects. Stage 3 assessed modality preference between color, grayscale, and enhanced images; on average, the 22 survey participants chose the enhanced image as better defined for nine out of 10 bite marks. The study has shown potential benefits for this new technique. However, further research is needed before use in the analysis of bite marks. © 2013 American Academy of Forensic Sciences.

  17. Talking tails : quantifying the development of tail biting in pigs

    NARCIS (Netherlands)

    Zonderland, J.J.

    2010-01-01

    Tail biting is an adverse behaviour characterised by manipulation of a pig’s tail by another pig resulting in tail damage and a possible tail biting outbreak. Tail biting is a common problem in the pig husbandry causing economic losses and reduced animal welfare worldwide. To prevent tail biting,

  18. Prospective medical evaluation of 7 dogs presented with fly biting.

    Science.gov (United States)

    Frank, Diane; Bélanger, Marie C; Bécuwe-Bonnet, Véronique; Parent, Joane

    2012-12-01

    Fly biting describes a syndrome in which dogs appear to be watching something and then snapping at it. Medical work-up of fly biting in dogs has never been reported. The aims of this case series were to characterize fly biting and perform a complete medical evaluation of dogs displaying fly biting.

  19. Prospective medical evaluation of 7 dogs presented with fly biting

    OpenAIRE

    Frank, Diane; Bélanger, Marie C.; Bécuwe-Bonnet, Véronique; Parent, Joane

    2012-01-01

    Fly biting describes a syndrome in which dogs appear to be watching something and then snapping at it. Medical work-up of fly biting in dogs has never been reported. The aims of this case series were to characterize fly biting and perform a complete medical evaluation of dogs displaying fly biting.

  20. Measuring the force of single protein molecule detachment from surfaces with AFM.

    Science.gov (United States)

    Tsapikouni, Theodora S; Missirlis, Yannis F

    2010-01-01

    Atomic force microscopy (AFM) was used to measure the non-specific detachment force of single fibrinogen molecules from glass surfaces. The identification of single unbinding events was based on the characteristics of the parabolic curves, recorded during the stretching of protein molecules. Fibrinogen molecules were covalently bound to Si(3)N(4) AFM tips, previously modified with 3-aminopropyl-dimethyl-ethoxysilane, through a homobifunctional poly(ethylene glycol) linker bearing two hydroxysulfosuccinimide esters. The most probable detachment force was found to be 210 pN, when the tip was retracting with a velocity of 1400 nm/s, while the distribution of the detachment distances indicated that the fibrinogen chain can be elongated beyond the length of the physical conformation before detachment. The dependence of the most probable detachment force on the loading rate was examined and the dynamics of fibrinogen binding to the surface were found amenable to the simple expression of the Bell-Evans theory. The theory's expansion, however, by incorporating the concept of the rupture of parallel residue-surface bonds could only describe the detachment of fibrinogen for a small number of such bonds. Finally, the mathematical expression of the Worm-Like Chain model was used to fit the stretching curves before rupture and two interpretations are suggested for the description of the AFM curves with multiple detachment events.

  1. On the tip calibration for accurate modulus measurement by contact resonance atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Passeri, D., E-mail: daniele.passeri@uniroma1.it [Department of Basic and Applied Sciences for Engineering, University of Rome Sapienza, Via A. Scarpa 16, 00161 Rome (Italy); Rossi, M. [Department of Basic and Applied Sciences for Engineering, University of Rome Sapienza, Via A. Scarpa 16, 00161 Rome (Italy); Centro di Ricerca per le Nanotecnologie Applicate all' Ingegneria della Sapienza (CNIS), University of Rome Sapienza, Piazzale A. Moro 5, 00185 Rome (Italy); Vlassak, J.J. [School of Engineering and Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138 (United States)

    2013-05-15

    Accurate quantitative elastic modulus measurements using contact resonance atomic force microscopy require the calibration of geometrical and mechanical properties of the tip as well as the choice of a suitable model for describing the cantilever-tip-sample system. In this work, we demonstrate with both simulations and experiments that the choice of the model influences the results of the calibration. Neglecting lateral force results in the underestimation of the tip indentation modulus and in the overestimation of the tip-sample contact radius. We propose a new approach to the calibration and data analysis, where lateral forces and cantilever inclination are neglected (which simplifies the calculations) and the tip parameters are assumed as fictitious. - Highlights: ► A calibration procedure is proposed for quantitative contact resonance AFM. ► It allows the use of simple analytical model that neglects lateral forces. ► Tip parameters are used as fictitious parameters. ► The approach is demonstrated with simulations and experiments.

  2. Quantifying seasonal and diel variation in Anopheline and Culex human biting rates in Southern Ecuador.

    Science.gov (United States)

    Ryan, Sadie J; Lippi, Catherine A; Boersch-Supan, Philipp H; Heydari, Naveed; Silva, Mercy; Adrian, Jefferson; Noblecilla, Leonardo F; Ayala, Efraín B; Encalada, Mayling D; Larsen, David A; Krisher, Jesse T; Krisher, Lyndsay; Fregosi, Lauren; Stewart-Ibarra, Anna M

    2017-11-22

    Quantifying mosquito biting rates for specific locations enables estimation of mosquito-borne disease risk, and can inform intervention efforts. Measuring biting itself is fraught with ethical concerns, so the landing rate of mosquitoes on humans is often used as a proxy measure. Southern coastal Ecuador was historically endemic for malaria (Plasmodium falciparum and Plasmodium vivax), although successful control efforts in the 2000s eliminated autochthonous transmission (since 2011). This study presents an analysis of data collected during the elimination period. Human landing catch (HLC) data for three mosquito taxa: two malaria vectors, Anopheles albimanus and Anopheles punctimacula, and grouped Culex spp. were examined for this study. These data were collected by the National Vector Control Service of the Ministry of Health over a 5-year time span (2007-2012) in five cities in southern coastal Ecuador, at multiple households, in all months of the year, during dusk-dawn (18:00-6:00) hours, often at both indoor and outdoor locations. Hurdle models were used to determine if biting activity was fundamentally different for the three taxa, and to identify spatial and temporal factors influencing bite rate. Due to the many different approaches to studying and quantifying bite rates in the literature, a glossary of terms was created, to facilitate comparative studies in the future. Biting trends varied significantly with species and time. All taxa exhibited exophagic feeding behavior, and outdoor locations increased both the odds and incidence of bites across taxa. Anopheles albimanus was most frequently observed biting, with an average of 4.7 bites/h. The highest and lowest respective months for significant biting activity were March and July for An. albimanus, July and August for An. punctimacula, and February and July for Culex spp. Fine-scale differences in endophagy and exophagy, and temporal differences among months and hours exist in biting patterns among

  3. Measuring the loss tangent of polymer materials with atomic force microscopy based methods

    International Nuclear Information System (INIS)

    Yablon, Dalia G; Grabowski, Jean; Chakraborty, Ishita

    2014-01-01

    Atomic force microscopy (AFM) quantitatively maps viscoelastic parameters of polymers on the nanoscale by several methods. The loss tangent, the ratio between dissipated and stored energy, was measured on a blend of thermoplastic polymer materials by a dynamic contact method, contact resonance, and by a recently developed loss tangent measurement by amplitude modulation AFM. Contact resonance measurements were performed both with dual AC resonance tracking and band excitation (BE), allowing for a reference-free measurement of the loss tangent. Amplitude modulation AFM was performed where a recent interpretation of the phase signal under certain operating conditions allows for the loss tangent to be calculated. The loss tangent measurements were compared with values expected from time–temperature superposed frequency-dependent dynamical mechanical curves of materials and reveal that the loss tangents determined from the BE contact resonance method provide the most accurate values. (paper)

  4. Note: Measurement system for the radiative forcing of greenhouse gases in a laboratory scale.

    Science.gov (United States)

    Kawamura, Yoshiyuki

    2016-01-01

    The radiative forcing of the greenhouse gases has been studied being based on computational simulations or the observation of the real atmosphere meteorologically. In order to know the greenhouse effect more deeply and to study it from various viewpoints, the study on it in a laboratory scale is important. We have developed a direct measurement system for the infrared back radiation from the carbon dioxide (CO2) gas. The system configuration is similar with that of the practical earth-atmosphere-space system. Using this system, the back radiation from the CO2 gas was directly measured in a laboratory scale, which roughly coincides with meteorologically predicted value.

  5. Surface topography characterization using an atomic force microscope mounted on a coordinate measuring machine

    DEFF Research Database (Denmark)

    De Chiffre, Leonardo; Hansen, H.N; Kofod, N

    1999-01-01

    The paper describes the construction, testing and use of an integrated system for topographic characterization of fine surfaces on parts having relatively big dimensions. An atomic force microscope (AFM) was mounted on a manual three-coordinate measuring machine (CMM) achieving free positioning...... of the AFM probe in space. This means that the limited measuring range of the AFM (40 mu m x 40 mu m x 2.7 um) can be extended by positioning the AFM probe using the movements of the CMM axes (400 mm x 100 mm x 75 mm). Evaluation of the background noise by determining the Sa value of an optical fiat gave...

  6. Reliable measurement of elastic modulus of cells by nanoindentation in an atomic force microscope

    KAUST Repository

    Zhou, Zhoulong

    2012-04-01

    The elastic modulus of an oral cancer cell line UM1 is investigated by nanoindentation in an atomic force microscope with a flat-ended tip. The commonly used Hertzian method gives apparent elastic modulus which increases with the loading rate, indicating strong effects of viscoelasticity. On the contrary, a rate-jump method developed for viscoelastic materials gives elastic modulus values which are independent of the rate-jump magnitude. The results show that the rate-jump method can be used as a standard protocol for measuring elastic stiffness of living cells, since the measured values are intrinsic properties of the cells. © 2011 Elsevier Ltd.

  7. A survey of dog bites in Salisbury.

    Science.gov (United States)

    Thomas, H F; Voss, S

    1991-12-01

    A recent survey of patients attending an Accident and Emergency (A&E) department serving several economically depressed Thanet coastal towns found that around 3 per 1000 of the resident population attended each year for the treatment of dog bite injuries (Thomas and Banks, 1990). We report a study of dog bite injuries treated in the A&E department serving Salisbury, a small prosperous Cathedral city, and surrounding villages. In comparison with Thanet, age specific incidence rates for dog bites show a similar pattern but only about half the overall incidence. Some reasons for these findings are suggested and extrapolations for national treatment figures are made.

  8. Visualized Multiprobe Electrical Impedance Measurements with STM Tips Using Shear Force Feedback Control

    Directory of Open Access Journals (Sweden)

    Luis Botaya

    2016-05-01

    Full Text Available Here we devise a multiprobe electrical measurement system based on quartz tuning forks (QTFs and metallic tips capable of having full 3D control over the position of the probes. The system is based on the use of bent tungsten tips that are placed in mechanical contact (glue-free solution with a QTF sensor. Shear forces acting in the probe are measured to control the tip-sample distance in the Z direction. Moreover, the tilting of the tip allows the visualization of the experiment under the optical microscope, allowing the coordination of the probes in X and Y directions. Meanwhile, the metallic tips are connected to a current–voltage amplifier circuit to measure the currents and thus the impedance of the studied samples. We discuss here the different aspects that must be addressed when conducting these multiprobe experiments, such as the amplitude of oscillation, shear force distance control, and wire tilting. Different results obtained in the measurement of calibration samples and microparticles are presented. They demonstrate the feasibility of the system to measure the impedance of the samples with a full 3D control on the position of the nanotips.

  9. A precision measurement of the neutron2. Probing the color force

    Energy Technology Data Exchange (ETDEWEB)

    Posik, Matthew R. [Temple Univ., Philadelphia, PA (United States)

    2014-01-01

    The g2 nucleon spin-dependent structure function measured in electron deep inelastic scattering contains information beyond the simple parton model description of the nucleon. It provides insight into quark-gluon correlations and a path to access the confining local color force a struck quark experiences just as it is hit by the virtual photon due to the remnant di-quark. The quantity d2, a measure of this local color force, has its information encoded in an x2 weighted integral of a linear combination of spin structure functions g1 and g2 and thus is dominated by the valence-quark region at large momentum fraction x. To date, theoretical calculations and experimental measurements of the neutron d2 differ by about two standard deviations. Therefore, JLab experiment E06-014, performed in Hall A, made a precision measurement of this quantity at two mean four momentum transfers values of 3.21 and 4.32 GeV2. Double spin asymmetries and absolute cross-sections were measured in both DIS and resonance regions by scattering longitudinally polarized electrons at beam energies of 4.74 and 5.89 GeV from a longitudinally and transversely polarized 3He target. Results for the absolute cross-sections and spin structure functions on 3He will be presented in the dissertation, as well as results for the neutron d2 and extracted color forces.

  10. Reliability and Validity of Force Platform Measures of Balance Impairment in Individuals With Parkinson Disease.

    Science.gov (United States)

    Harro, Cathy C; Marquis, Alicia; Piper, Natasha; Burdis, Chris

    2016-12-01

    Complex movement and balance impairments in people with Parkinson disease (PD) contribute to high fall risk. Comprehensive balance assessment is warranted to identify intrinsic fall risk factors and direct interventions. The purpose of this study was to examine the psychometric properties of 3 balance measures of a force platform (FP) system in people with PD. Forty-two community-dwelling individuals with idiopathic PD completed the testing protocol. Test-retest reliability was assessed for the Limits of Stability Test (LOS), Motor Control Test (MCT), and Sensory Organization Test (SOT). Intraclass correlation coefficients (ICC [2,1]) were calculated to determine test-retest reliability and minimal detectable change. Validity was assessed by comparing the FP measures with criterion gait and balance measures using Pearson product moment correlations. Multiple regression analyses examined the contribution of PD characteristics to FP measures. All primary FP variables demonstrated excellent test-retest reliability (ICC=.78-.92). The SOT and LOS demonstrated fair to good correlations with criterion measures, whereas the MCT had fair correlations to balance measures only. Both SOT composite equilibrium and MCT average latency were moderately associated with disease severity. This study's sample had a relatively small number of participants with a positive fall history, which may limit the generalizability of the findings. This study's findings provide support that FP measures are reliable and valid tests of balance impairment in people with PD. Disease severity was significantly associated with SOT and MCT measures, perhaps reflecting that these tests are meaningful indicators of decline in postural control with disease progression. Force platform measures may provide valuable quantitative information about underlying balance impairments in people with PD to guide therapeutic interventions for fall risk reduction. © 2016 American Physical Therapy Association.

  11. Cellular Force Microscopy for in Vivo Measurements of Plant Tissue Mechanics1[W][OA

    Science.gov (United States)

    Routier-Kierzkowska, Anne-Lise; Weber, Alain; Kochova, Petra; Felekis, Dimitris; Nelson, Bradley J.; Kuhlemeier, Cris; Smith, Richard S.

    2012-01-01

    Although growth and morphogenesis are controlled by genetics, physical shape change in plant tissue results from a balance between cell wall loosening and intracellular pressure. Despite recent work demonstrating a role for mechanical signals in morphogenesis, precise measurement of mechanical properties at the individual cell level remains a technical challenge. To address this challenge, we have developed cellular force microscopy (CFM), which combines the versatility of classical microindentation techniques with the high automation and resolution approaching that of atomic force microscopy. CFM’s large range of forces provides the possibility to map the apparent stiffness of both plasmolyzed and turgid tissue as well as to perform micropuncture of cells using very high stresses. CFM experiments reveal that, within a tissue, local stiffness measurements can vary with the level of turgor pressure in an unexpected way. Altogether, our results highlight the importance of detailed physically based simulations for the interpretation of microindentation results. CFM’s ability to be used both to assess and manipulate tissue mechanics makes it a method of choice to unravel the feedbacks between mechanics, genetics, and morphogenesis. PMID:22353572

  12. Critical-Dimension Measurement using Multi-Angle-Scanning Method in Atomic Force Microscope

    Science.gov (United States)

    Murayama, Ken; Gonda, Satoshi; Koyanagi, Hajime; Terasawa, Tsuneo; Hosaka, Sumio

    2006-07-01

    We have developed a new critical dimension (CD) measurement technique using atomic force microscope (AFM) which can measure width-dimensions and examine sidewall-shapes of fine patterns on a wafer. The technique employs a flared-type tip in combination with digital probing and multi-angle scanning mechanism that allows the tip to trace the sidewalls on both sides of a feature (or trench) by making physical contacts with the sidewall surface. First, by using finite element method (FEM) we analyzed deformation of the tip and cantilever to compensate errors caused by the deformation. To verify our compensation method we measured quartz reference patterns either with perpendicular sidewalls or undercuts. In this paper we will describe the applications and usefulness of this multi-angle operation and show some measurement results of ArF resist patterns with 200 nm width and 400 nm depth that were obtained with a flared tip of 120 nm diameter.

  13. A Study of the Confinement Induced Sponge to Lamellar Phase Transformation by Direct Force Measurement

    International Nuclear Information System (INIS)

    Antelmi, David

    1996-10-01

    The interactions between two macroscopic walls immersed in an isotropic symmetric sponge phase (L 3 ) at different volume fractions, Φ, were studied with a surface force apparatus. The purpose of these experiments was to investigate the behaviour of the sponge phase when confined between two smooth rigid surfaces. Particular attention was given to investigating this behaviour as the bulk transition to the lamellar phase (L α ) was approached. At temperatures far from the L 3 /L α bulk transition temperature, the force-distance profile showed weak oscillations with a periodicity approximately equal to twice the characteristic length, ξ, measured for the sponge phase from small angle x-ray scattering. Furthermore, the oscillations were superimposed on an exponential attractive background that decayed with an order parameter correlation length of 2-3 times ξ The attractive background was explained by the enhancement of the sponge order in the vicinity of the rigid walls. The structural oscillations observed in the force-distance profile, although not completely understood, were discussed in terms of the packing of sponge cells (cell size ξ). The significance of the observed periodicity (2ξ) may indicate the importance of the symmetric nature of the sponge phase. By moving pairs of cells in response to an applied strain, the symmetry of the sponge structure is protected. As the temperature increased towards the L 3 /L α bulk transition temperature, an abrupt change in the force-distance profile was observed at a threshold separation labelled D* in . A different force regime was observed for separations below D* in which oscillated with a periodicity that was twice the reticular spacing, d, for a L α phase of similar Φ. The force oscillations were superimposed on an attractive background that was almost linear. These observations were consistent with a first order phase transition from the sponge phase to the lamellar phase, induced by the confinement, where

  14. Ultrasound power measurements of HITU transducer with a more stable radiation force balance

    International Nuclear Information System (INIS)

    Karaboece, B; Sadiko'lu, E; Bilgic, E

    2011-01-01

    A new radiation force balance (RFB) system was established at Turkish National Metrology Institute (UME) Ultrasonics Laboratory for High intensity therapeutic ultrasound (HITU) power measurements. The new system is highly stable at high power levels up to 500 Watts. The measurement system consists of a Plexiglas cylindrical balance arm, target mounting scale disks, conical reflecting and absorbing targets, adjustment nuts, and a hanging wire. Both of the two sides of balance were mounted similar size and weight targets. The equilibrium of the balance arm can be adjusted with nuts on screws located at both sides of the balance arm. Transducer was mounted to bottom of water tank. Absorbers in the bottom and the near walls of the tank were used for reflecting target case. Ultrasound power was applied to one scale of the balance where the reflecting/absorbing target was mounted and corresponding force was measured on the other scale of balance where was connected to a balance with a thin wire while the thin rest standing on a support. Ultrasound power of two HITU transducers at frequencies 0.93 MHz, 1.1 MHz and 3.3 MHz were measured with conventional and new system, the values were compared and uncertainty components were assessed in this paper.

  15. Comparison of optical and electrical measurements of the pantograph-catenary contact force

    Science.gov (United States)

    Bocciolone, Marco; Bucca, Giuseppe; Collina, Andrea; Comolli, Lorenzo

    2010-09-01

    In railway engineering the monitoring of contact force between pantograph and catenary gives information about the interaction between the two systems and it is useful to check the status of the overhead line. Indeed the failure of the catenary is one of the main causes of out of order problems. This study was conducted in a test campaign on an underground train instrumented with sensors able to monitor the line status. One of the more important measured quantities is the pantograph contact force, and two measurement systems were implemented: one optical and another electrical. The optical one was based on FBG sensors applied on the pantograph collector strip; the electrical one was based on two load cells positioned at the sides of the collector strip. The in-line measurements show that the optical solution is very promising, providing very reliable results that can be successfully used in the monitoring application, allowing the determination of the critical point in the line. The thermal compensation of any FBG sensors is a known problem and here is no exception: a thermal compensator was used to get also mean value measurements and the results are discussed.

  16. Ultrasound power measurements of HITU transducer with a more stable radiation force balance

    Energy Technology Data Exchange (ETDEWEB)

    Karaboece, B; Sadiko' lu, E; Bilgic, E, E-mail: baki.karaboce@ume.tubitak.gov.t [Tuebitak Ulusal Metroloji Enstituesue (UME), P.K. 54 41470 Gebze-Kocaeli (Turkey)

    2011-02-01

    A new radiation force balance (RFB) system was established at Turkish National Metrology Institute (UME) Ultrasonics Laboratory for High intensity therapeutic ultrasound (HITU) power measurements. The new system is highly stable at high power levels up to 500 Watts. The measurement system consists of a Plexiglas cylindrical balance arm, target mounting scale disks, conical reflecting and absorbing targets, adjustment nuts, and a hanging wire. Both of the two sides of balance were mounted similar size and weight targets. The equilibrium of the balance arm can be adjusted with nuts on screws located at both sides of the balance arm. Transducer was mounted to bottom of water tank. Absorbers in the bottom and the near walls of the tank were used for reflecting target case. Ultrasound power was applied to one scale of the balance where the reflecting/absorbing target was mounted and corresponding force was measured on the other scale of balance where was connected to a balance with a thin wire while the thin rest standing on a support. Ultrasound power of two HITU transducers at frequencies 0.93 MHz, 1.1 MHz and 3.3 MHz were measured with conventional and new system, the values were compared and uncertainty components were assessed in this paper.

  17. Influence of Halide Solutions on Collagen Networks: Measurements of Physical Properties by Atomic Force Microscopy

    Science.gov (United States)

    Kempe, André; Lackner, Maximilian

    2016-01-01

    The influence of aqueous halide solutions on collagen coatings was tested. The effects on resistance against indentation/penetration on adhesion forces were measured by atomic force microscopy (AFM) and the change of Young's modulus of the coating was derived. Comparative measurements over time were conducted with halide solutions of various concentrations. Physical properties of the mesh-like coating generally showed large variability. Starting with a compact set of physical properties, data disperse after minutes. A trend of increase in elasticity and permeability was found for all halide solutions. These changes were largest in NaI, displaying a logical trend with ion size. However a correlation with concentration was not measured. Adhesion properties were found to be independent of mechanical properties. The paper also presents practical experience for AFM measurements of soft tissue under liquids, particularly related to data evaluation. The weakening in physical strength found after exposure to halide solutions may be interpreted as widening of the network structure or change in the chemical properties in part of the collagen fibres (swelling). In order to design customized surface coatings at optimized conditions also for medical applications, halide solutions might be used as agents with little impact on the safety of patients. PMID:27721994

  18. Development of a Hybrid Atomic Force Microscopic Measurement System Combined with White Light Scanning Interferometry

    Directory of Open Access Journals (Sweden)

    Xiaotang Hu

    2011-12-01

    Full Text Available A hybrid atomic force microscopic (AFM measurement system combined with white light scanning interferometry for micro/nanometer dimensional measurement is developed. The system is based on a high precision large-range positioning platform with nanometer accuracy on which a white light scanning interferometric module and an AFM head are built. A compact AFM head is developed using a self-sensing tuning fork probe. The head need no external optical sensors to detect the deflection of the cantilever, which saves room on the head, and it can be directly fixed under an optical microscopic interferometric system. To enhance the system’s dynamic response, the frequency modulation (FM mode is adopted for the AFM head. The measuring data can be traceable through three laser interferometers in the system. The lateral scanning range can reach 25 mm × 25 mm by using a large-range positioning platform. A hybrid method combining AFM and white light scanning interferometry is proposed to improve the AFM measurement efficiency. In this method, the sample is measured firstly by white light scanning interferometry to get an overall coarse morphology, and then, further measured with higher resolution by AFM. Several measuring experiments on standard samples demonstrate the system’s good measurement performance and feasibility of the hybrid measurement method.

  19. How to Stop Biting Your Nails

    Medline Plus

    Full Text Available ... Center Coding and reimbursement Coding MACRA Fee schedule Managing a practice Prior authorization assistance Teledermatology Compliance HIT ... Child nail care Manicure safety Nail biting Nail changes a dermatologist should examine Anti-aging skin care ...

  20. [Bites of venomous snakes in Switzerland].

    Science.gov (United States)

    Plate, Andreas; Kupferschmidt, Hugo; Schneemann, Markus

    2016-06-08

    Although snake bites are rare in Europe, there are a constant number of snake bites in Switzerland. There are two domestic venomous snakes in Switzerland: the aspic viper (Vipera aspis) and the common European adder (Vipera berus). Bites from venomous snakes are caused either by one of the two domestic venomous snakes or by an exotic venomous snake kept in a terrarium. Snake- bites can cause both a local and/or a systemic envenoming. Potentially fatal systemic complications are related to disturbances of the hemostatic- and cardiovascular system as well as the central or peripheral nervous system. Beside a symptomatic therapy the administration of antivenom is the only causal therapy to neutralize the venomous toxins.

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  2. How to Stop Biting Your Nails

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  3. Tarantula bite leads to death and gangrene

    Directory of Open Access Journals (Sweden)

    Banerjee Kalyan

    1997-01-01

    Full Text Available Chilobrachys hardwikii-giant black hairy spider bite produced two deaths, one case of gangrene of the foot and urticarial rashes in another person in a remote village of Churulia 30 km from Asansol.

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  8. Eosinophilic Fasciitis Induced by Fire Ant Bites

    OpenAIRE

    Mallepalli, Jyothi R.; Quinet, Robert J.; Sus, Rachana

    2008-01-01

    Purpose: To describe a case of eosinophilic fasciitis likely related to proximate fire ant bites and review the literature to summarize the etiology and clinical, laboratory, histopathological, and therapeutic aspects of eosinophilic fasciitis.

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