Strain Gauge Transducers Research Articles

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To the Editor

The Gut is not only the Target but a Source of Inflammatory Mediators Inhibiting Gastrointestinal Motility During Sepsis

Background: Sepsis is a common problem in intensive care patients leading to multi-organ failure and gastrointestinal paralysis. Aim: The aim of the study was to investigate whether the gastrointestinal tract is not only the target but also the source of inflammatory mediators inhibiting gastrointestinal motility. Methods: Mesenteric lymph was obtained from rats in which a sepsis was induced by lipopolysaccharide (LPS) intraperitoneally. Gastrointestinal motility was recorded following mesenteric lymph- or TNFα infusion into the jugular vein of separate healthy recipient rats using the strain gauge transducer technique. Results: Infusion of sepsis lymph significantly impairs gastric and colonic motility, decreasing the motility-index in the stomach and colon by about 57% and 21% respectively in comparison to baseline motility. Among other inflammatory mediators, TNFα plays an important role in mediating the inhibitory effect of mesenteric lymph on gastrointestinal motility during sepsis. Conclusions: The gastrointestinal tract is the source and the target of inflammatory mediators released during sepsis causing paralytic ileus.

A vertical ground reaction force-measuring treadmill for the analysis of prosthetic limbs

This paper presents the development of an instrumented-treadmill, designed for use in the evaluation of prosthetic limbs during amputee running. The motorised treadmill was chosen for this study because of its advantages over conventional ground mounted force platforms, e.g. decreased time required for the data- collection, laboratory space required, repeatability, control of speed, and improved statistical power through collection of a high number of successive foot contacts. The long-term aim of this work is to investigate amputee running and thus identify prosthetic limb/wearer characteristics, which may improve the training process and subsequent running experience. An existing treadmill was modified to measure the ground reaction force underneath the belt. A new treadmill bed was designed using finite element analysis techniques. Four biaxial strain gauge transducers were designed and fabricated in-house to measure the applied loads. The instrumented-treadmill has been statically and dynamically tested and calibrated, showing a maximum error of ± 3% and crosstalk of ± 4% to the horizontal force components, a hysteresis up to 8 N, and a 250 Hz natural frequency. Associated software has been developed to capture, process and display information related to gait data in a format suitable for left and right limb comparison. A pilot study was conducted to examine the force-measuring treadmill for evaluating amputee running.

Suture-Button Construct for Interosseous Ligament Reconstruction in Longitudinal Radioulnar Dissociations: A Biomechanical Study

Longitudinal radioulnar dissociation is a triad of injuries consisting of distal radioulnar joint disruption, interosseous ligament complex (IOLC) tear, and radial head fracture. This renders the forearm longitudinally unstable, resulting in proximal migration of the radius and ulnar-sided wrist degeneration. We hypothesized that reconstruction of the central band of the IOLC in cadaver forearms using a Mini-TightRope suture-button construct would restore native forearm stability. We implanted 8 fresh-frozen cadaver arms with steel beads into the distal radius and ulna, mounted them on an MTS machine, and cyclically loaded them from 13 N distraction to 130 N compression. Bead motion was recorded fluoroscopically and analyzed using Image-Pro Express software. We measured distal ulnar forces using strain gauge transducers. Longitudinal radioulnar dissociation injuries were created by radial head excision and complete IOLC and triangular fibrocartilage complex disruption. At each stage, arms were tested with and without a radial head implant. We reconstructed the central band of the IOLC using a Mini-TightRope and tightened until the distal radioulnar joint was reduced fluoroscopically. We used multiple-comparison analysis of variance with Tukey's Honestly Significant Difference test for statistical analysis. The intact arms had an average radioulnar axial displacement of 0.7 ± 0.8 mm and distal ulnar impaction force of 16.7 ± 11.1 N (per 100 N of axial load on the forearm). After destabilization, the radioulnar displacement increased to 10.7 ± 3.9 mm (p < .001) and ulnar load increased 312%, to an average of 52.2 ± 25.7 N (p < .001). After IOLC reconstruction, average displacement decreased to 2.2 ± 0.9 mm with a distal ulnar load of 19.05 ± 13.5 N (not significantly different from intact arms). In this cadaveric study, Mini-TightRope IOLC reconstruction with or without a radial head prosthesis significantly reduced distal ulnar impaction forces to that of the native forearm, while limiting radioulnar displacement to near-anatomic levels.

Formation of highly conductive composite coatings and their applications to broadband antennas and mechanical transducers

Tight networks of interwoven carbon nanotube bundles are formed in our highly conductive composite. The composite possesses properties suggesting a two-dimensional percolative network rather than other reported dispersions displaying three-dimensional networks. Binding nanotubes into large but tight bundles dramatically alters the morphology and electronic transport dynamics of the composite. This enables it to carry higher levels of charge in the macroscale leading to conductivities as high as 1600 S/cm. We now discuss in further detail, the electronic and physical properties of the nanotube composites through Raman spectroscopy and transmission electron microscopy analysis. When controlled and used appropriately, the interesting properties of these composites reveal their potential for practical device applications. For instance, we used this composite to fabricate coatings, which improve the properties of an electromagnetic antenna/amplifier transducer. The resulting transducer possesses a broadband range up to GHz frequencies. A strain gauge transducer was also fabricated using changes in conductivity to monitor structural deformations in the composite coatings.

Central orexin-A increases gastric motility in rats

Orexin receptor type-1 (OX1R) is expressed in the dorsal motor nucleus of vagi (DMV). Although orexin-A (OXA) plays an important role in mediating stress responses, it remains unclear how central OXA regulates gastric dysmotility induced by stress. Acute restraint stress (ARS) delays solid gastric emptying via the central corticotropin releasing factor (CRF) and peripheral autonomic neural pathways. We have previously shown that ARS impairs postprandial antro-pyloric coordination and delays solid gastric emptying in rats. We also showed that postprandial gastric contractions were augmented in response to ARS in rats. However, the mechanism of augmented postprandial gastric contractions induced by ARS remains unclear. We tested the hypothesis that augmented gastric motility induced by ARS is mediated via the central OX1R. We also assessed the role of endogenous OXA in the mediation of gastric motility under non-stressed conditions in conscious rats. A strain gauge transducer was implanted on the antrum to record postprandial gastric motility. To investigate whether endogenous OXA is involved in ARS-induced augmented gastric motility, selective OX1R antagonist, SB-334867 (16 μg), was administered intracerebroventricularly (icv). Icv-injection of SB-334867 abolished the augmented gastric contractions induced by ARS. Spontaneous postprandial gastric motility was enhanced by icv-injection of OXA (10 μg), while it was attenuated by icv-injection of SB-3334867. It is suggested that central OXA mediates augmented gastric motility induced by ARS in rats. Central OXA also modulates postprandial gastric contractions in non-stressed conditions.

Physiological characteristics of gastric contractions and circadian gastric motility in the free-moving conscious house musk shrew (Suncus murinus)

Although many studies have demonstrated the physiological action of motilin on the migrating motor complex, the precise mechanisms remain obscure. To obtain new insights into the mechanisms, we focused on the house musk shrew (Suncus murinus, suncus used as a laboratory name) as a small model animal for in vivo motilin study, and we studied the physiological characteristics of suncus gastrointestinal motility. Strain gauge transducers were implanted on the serosa of the gastric body and duodenum, and we recorded gastrointestinal contractions in the free-moving conscious suncus and also examined the effects of intravenous infusion of various agents on gastrointestinal motility. During the fasted state, the suncus stomach and duodenum showed clear migrating phase III contractions (intervals of 80-150 min) as found in humans and dogs. Motilin (bolus injection, 100-300 ng/kg; continuous infusion, 10-100 ng·kg(-1)·min(-1)) and erythromycin (80 μg·kg(-1)·min(-1)) induced gastric phase III contractions, and motilin injection also increased the gastric motility index in a dose-dependent manner (P < 0.05, vs. saline). Pretreatment with atropine completely abolished the motilin-induced gastric phase III contractions. On the other hand, in the free-feeding condition, the suncus showed a relatively long fasting period in the light phase followed by spontaneous gastric phase III contractions. The results suggest that the suncus has almost the same gastrointestinal motility and motilin response as those found in humans and dogs, and we propose the suncus as a new small model animal for studying gastrointestinal motility and motilin in vivo.

Length and elasticity of side reins affect rein tension at trot

This study investigated the horse's contribution to tension in the reins. The experimental hypotheses were that tension in side reins (1) increases biphasically in each trot stride, (2) changes inversely with rein length, and (3) changes with elasticity of the reins. Eight riding horses trotted in hand at consistent speed in a straight line wearing a bit and bridle and three types of side reins (inelastic, stiff elastic, compliant elastic) were evaluated in random order at long, neutral, and short lengths. Strain gauge transducers (240 Hz) measured minimal, maximal and mean rein tension, rate of loading and impulse. The effects of rein type and length were evaluated using ANOVA with Bonferroni post hoc tests. Rein tension oscillated in a regular pattern with a peak during each diagonal stance phase. Within each rein type, minimal, maximal and mean tensions were higher with shorter reins. At neutral or short lengths, minimal tension increased and maximal tension decreased with elasticity of the reins. Short, inelastic reins had the highest maximal tension and rate of loading. Since the tension variables respond differently to rein elasticity at different lengths, it is recommended that a set of variables representing different aspects of rein tension should be reported.

Central orexin-A changes the gastrointestinal motor pattern from interdigestive to postprandial in rats

Orexin-A, also described as hypocretin-I, was discovered in the extracts of the rat brain. OXA is implicated in a wide variety of physiological functions, such as feeding, arousal, behavioral activity, energy homeostasis and gastrointestinal motility. Orexin receptor type-1 is highly expressed in the dorsal motor nucleus of vagus. Although peripherally administered OXA abolishes small intestinal interdigestive contractions in rats, it still remains unclear whether central OXA affects interdigestive GI motility in rats. Two strain gauge transducers were attached on the antrum and duodenum to record circular muscle contractions. Spontaneous gastroduodenal contractions were recorded in freely moving conscious rats. OXA (1-20 µg) was administered intracerebroventricularly (icv). Atropine pretreatment (1 mg/kg, ip) and truncal vagotomy were performed to elucidate the neural pathways of central OXA. OXA (1–20 µg) dose-dependently disrupted the interdigestive phase III-like contractions and induced an irregular postprandial-like motility pattern in the stomach and duodenum. The stimulatory effect of OXA on gastroduodenal postprandial-like motility pattern was abolished by atropine and truncal vagotomy. Central administration (icv) of selective OXA receptor antagonist, SB-334867 (16 µg), enhanced gastric spontaneous phase III-like contractions. It is suggested that central OXA changes GI motor pattern from interdigestive to postprandial via the vagal cholinergic pathways. Endogenous OXA may have an inhibitory role in interdigestive GI motility in rats.

Association between plasma ghrelin and motilin levels during MMC cycle in conscious dogs

Background Migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. Gastric phase III contractions of MMC are regulated by motilin, but not ghrelin, in dogs. Ghrelin regulates feeding activity in dogs and rodents. It remains unclear how motilin and ghrelin interact during the MMC cycle in dogs. Methods Four strain gauge transducers were implanted on stomach and intestine in 6 female dogs. To investigate the correlation between ghrelin and motilin, plasma motilin and acyl ghrelin (active type) levels were measured by radioimmunoassay (RIA) during MMC cycle. Results The peak of plasma motilin levels was always observed at the period of gastric phase III contractions. The peak of ghrelin levels were followed 20–25 min after the peak of plasma motilin levels in 13 cases of 18 observations (72.2%). These were frequently observed at the early stage of gastric phase I contractions. In 3 of 16 observations (18.8%), the ghrelin peak was not associated with the motilin peaks. Immediately after the feeding, the interdigestive GI motor pattern was changed to the postprandial pattern. No significant increases of the plasma motilin levels and ghrelin levels were observed after the feeding. Conclusion This is the first demonstration showing the correlation between ghrelin and motilin levels during gastric MMC cycle in conscious dogs. As it is rather difficult to evaluate the hunger score in dogs, it remains unclear whether increased ghrelin levels after finishing gastric phase III contractions may mediate hunger sensation in dogs.

Central oxytocin attenuates augmented gastric postprandial motility induced by restraint stress in rats

Restraint stress delays gastric emptying via uncoordinated motility pattern in rats. Central oxytocin has anxiolytic effects and attenuates the hypothalamic-pituitary-adrenal (HPA) axis in response to stress and facilitates stress-induced delayed gastric emptying. However, the role of central oxytocin in regulating gastric motility remains unknown. Postprandial gastric motility was recorded via a strain-gauge transducer, implanted on the antrum in Sprague–Dawley (SD) rats. To investigate whether central and peripheral oxytocin are involved in gastric motility, oxytocin (10 μg) was administered intracerebroventricularly (icv) and intraperitoneally (ip). Central and peripheral oxytocin administration did not affect the postprandial gastric motility under non-stressed conditions. Restraint stress augmented gastric contractions. Central administration of oxytocin, but not peripheral administration, abolished the augmented postprandial gastric contractions induced by restraint stress. Oxytocin facilitates stress-induced delayed gastric emptying via alleviating uncoordinated gastric motility. Oxytocin might be a candidate for the treatment of stress-induced GI motility disorders.

COMPARISON OF TONOMETRIC AND OSCILLOMETRIC METHOD FOR MEASURING ARTERIAL STIFFNESS: PP.14.42

Introduction: Pulse wave velocity (PWV) and augmentation index (AIx) are parameters of arterial stiffness and wave reflection. PWV and AIx are strong indicators for cardiovascular risk and are used increasingly in clinical practice (1). The aim of our study was to compare two methods for estimating PWV and AIx - SphygmoCor (SC) (AtCor Medical, Sydney, Australia) and Arteriograph (ART) (TensioMedTM Kft, Budapest, Hungary)(2) Methods: SphygmoCor determines pulse wave and calculated central parameters based on the principle of applanation tonometry on radial, carotid and femoral artery using strain gauge transducer. Arteriograph determines central parameters by oscillometric method that measures periodic pressure changes in the inflated cuff placed on upper arm. We examined 33 patients with arterial hypertension. First tonometric (SC) and after that oscilometric method (ART) were used. Validity was evaluated by Pearson's correlation, Bland-Altman analysis. Results: Mean PWV(SC) was 8,71 m/s ± 2,84 and PWV(ART) was 9,93 m/s ± 3,13. AIx(SC) was 20,27 ± 13,74 and AIx(ART) 30,66 ± 16,99. Paired sample test is shown in table 1.There was significant correlation between the PWV (SC) and PWV)ART) readings (r = 0.566, p < 0.001, n = 33). Correlation between Aix(SC) and Aix(ART) was significant (r = 0,722, p < 0,001, n = 33). Bland-Altman plot show for both parameters a big average discrepancy between methods, especially for AIx Conclusion: Big average discrepancy (bias) between methods, especially for Aix, suggests limited validity of Arteriograph compared to SphygmoCor. Literature 1. Laurent,S, Cockcroft,J, Van-Bortel,L, et al. Expert consensus document on arterial stiffness: methodological issues and clinical applications. European Heart Journal 2006;27(no.21): 2. Baulmann,J, Schillings,U, Rickert,S et al. A new oscillometric method for assessment of arterial stiffness: comparison with tonometric and piezo-electronic methods. Journal of hypertension 2008;26(no.3):

Effects of autonomic nerve stimulation on colorectal motility in rats

Several disease processes of the colon and rectum, including constipation and incontinence, have been associated with abnormalities of the autonomic nervous system. However, the autonomic innervation to the colon and rectum are not fully understood. The aims of this study were to investigate the effect of stimulation of vagus nerves, pelvic nerves (PN) and hypogastric nerves (HGN) on colorectal motility in rats. Four strain gauge transducers were implanted on the proximal colon, mid colon, distal colon and rectum to record circular muscle contractions in rats. Electrical stimulation was administered to the efferent distal ends of the cervical vagus nerve, PN and HGN. Motility index (MI) was evaluated before and during stimulation. Electrical stimulation (5-20 Hz) of the cervical vagus elicited significant contractions in the mid colon and distal colon, whereas less pronounced contractions were observed in the proximal colon. Pelvic nerves stimulation elicited significant contractions in the rectum as well as the mid colon and distal colon. Atropine treatment almost completely abolished the contractions induced by vagus nerve and PN stimulation. Hypogastric nerves stimulation caused relaxations in the rectum, mid colon and distal colon. The relaxations in response to HGN stimulation were abolished by propranolol. Vagal innervation extends to the distal colon, while the PN has projections in the distribution of the rectum through the mid colon. This suggests a pattern of dual parasympathetic innervation in the left colon. Parasympathetic fibers regulate colorectal contractions via muscarinic receptors. The HGN mainly regulates colorectal relaxations via beta-adrenoceptors.

Vagal Nerve Regulation Is Essential for the Increase in Gastric Motility in Response to Mild Exercise

It has been shown that mild to moderate exercise can accelerate gastric emptying in humans. However, understanding of the underlying mechanism is hampered by the lack of appropriate animal models. To investigate the effects of mild exercise on gastric motility, we developed an animal model, in which strain gauge transducers were surgically planted on the antral surfaces of female Sprague-Dawley rats. We continuously recorded the contractions of gastric circular muscle in unrestrained conscious rats, divided into four groups: sham-operated exercise, sham-operated sedentary, vagotomized exercise, and vagotomized sedentary. The rats were trained for 3 weeks, and gastric motility was monitored before and after exercise. Although exercise accelerates gastric antral contraction in sham-operated rats, this effect was absent in the vagotomized exercise group, indicating the involvement of the vagal nerve in the exercise-mediated increase in gastric motility. Among the four groups, daily food intake was highest in the sham-operated exercise group. In contrast, the vagotomized exercise group exhibited the smallest body weight gain. Severe gastric retention was observed in vagotomized rats, suggesting a role of the vagal nerve in facilitating food movement and digestion in the stomach. Moreover, at the end of the 3-week exercise, there were no differences in plasma levels of growth hormone, peptid YY, and ghrelin among the four groups. These results indicate that in response to a mild physical exercise challenge, the vagal nerve stimulates gastric motility and enhances the ability of the stomach to process food. Our findings highlight the significance of neuronal control of stomach function.

Definitive validation of acb for measuring stomach contraction using strain-gauge in rats

Event Abstract Back to Event Definitive validation of acb for measuring stomach contraction using strain-gauge in rats Madileine Americo1*, Rozemeire Marques2, Ednaldo Zandona1, Murilo Stelzer1, Marcelo Agostinho1 and Jose R. Miranda1 1 UNESP, Univ Estadual Paulista, Brazil 2 UNESP, Univ Estadual Paulista, Department of Surgery and Orthopedic – Faculdade de Medicina , Brazil Our aim was to validate a biomagnetic method (Alternate Current Biosusceptometry, ACB) for monitoring contraction in vitro and in rats. All the experiments were performed with magnetic marker and strain-gauge transducer previously implanted on latex balloon and on 10 rats under the serosa of the stomach. All animals were anesthetized (pentobarbital, 40 mg.kg-1) and an ACB sensor was positioned on abdominal surface. One recording of 30 minutes was obtained in vitro and two recordings were obtained with each animal varying the prandial state (fasting or fed). An ACB sensor consists of two pairs of coils (excitation/detection) separated by a fixed distance, in a first order gradiometric configuration. The proximity of a magnetic material causes an unbalancing of the magnetic flux in the system, generating a signal which depends on the distance between the sensor and the magnetic material. All signals were analyzed in MatLab by visual inspection and using Butterworth band-pass filters by Fast Fourier Transform. Temporal cross-correlation (R) analysis was used to determine correlation between signals. A strong temporal correlation between ACB and strain-gauge recordings was found in vitro (R=0.99±0.02; p<0.0001) and in vivo (R=0.90±0.07; p<0.005). Frequencies measured during both fasting (0.058±0.007 Hz for ACB vs. 0.059±0.008 Hz for strain-gauge) and postprandial (0.068±0.007 Hz for ACB vs. 0.066±0.006 Hz for strain-gauge) period were consistently different (p<0.002). Our results confirmed that ACB is capable to detect the gastric contraction directly from the movement of the gastric wall, through the magnetic maker fixed, and support an innovative method of recording punctually mechanical activity of the stomach. Another ACB advantage is the possibility of monitoring gastrointestinal motility through ingestion of magnetic material instead of its implantation. In conclusion, the ACB is a sensitive method for assessment of gastrointestinal contraction in rats. Conference: Biomag 2010 - 17th International Conference on Biomagnetism , Dubrovnik, Croatia, 28 Mar - 1 Apr, 2010. Presentation Type: Poster Presentation Topic: Instrumentation and Multi-modal Integrations: MEG, Low-field MRI,EEG, fMRI,TMS,NIRS Citation: Americo M, Marques R, Zandona E, Stelzer M, Agostinho M and Miranda JR (2010). Definitive validation of acb for measuring stomach contraction using strain-gauge in rats. Front. Neurosci. Conference Abstract: Biomag 2010 - 17th International Conference on Biomagnetism . doi: 10.3389/conf.fnins.2010.06.00412 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 09 Apr 2010; Published Online: 09 Apr 2010. * Correspondence: Madileine Americo, UNESP, Univ Estadual Paulista, Sao Paulo, Brazil, madi_americo@yahoo.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Madileine Americo Rozemeire Marques Ednaldo Zandona Murilo Stelzer Marcelo Agostinho Jose R Miranda Google Madileine Americo Rozemeire Marques Ednaldo Zandona Murilo Stelzer Marcelo Agostinho Jose R Miranda Google Scholar Madileine Americo Rozemeire Marques Ednaldo Zandona Murilo Stelzer Marcelo Agostinho Jose R Miranda PubMed Madileine Americo Rozemeire Marques Ednaldo Zandona Murilo Stelzer Marcelo Agostinho Jose R Miranda Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Mechanism of interdigestive migrating motor complex in conscious dogs

The migrating motor complex (MMC) is well characterized by the appearance of gastrointestinal contractions in the interdigestive state. This study was designed to clarify the mechanisms of gastric MMC (G-MMC) and intestinal MMC (I-MMC) in conscious dogs. Five strain gauge transducers were implanted on the stomach and intestine. To investigate the correlation between luminal 5-HT and phase III contractions, gastric and duodenal juices were collected during the MMC cycle. The 5-HT concentrations in gastric and duodenal juice were measured by HPLC. To investigate whether luminal 5-HT initiates MMC, 5-HT (10(-8)-10(-6) M, 10 ml) was administered into the duodenum 20 min after gastric phase III. To investigate the involvement of 5-HT(3) or 5-HT(4) receptors in mediating G-MMC and I-MMC, 5-HT(3) antagonists (ondansetron) or 5-HT(4) antagonists (GR 125,487) were infused for 120 min. Luminal administration of 5-HT (10(-6) M) initiated duodenal phase II followed by G-MMC and I-MMC with a concomitant increased release of plasma motilin. The duodenal 5-HT concentration was significantly increased during phase II (59 +/- 9 ng/ml) and phase III (251 +/- 21 ng/ml) compared to that of phase I (29 +/- 5 ng/ml). On the other hand, the 5-HT content in the stomach was not significantly changed throughout the MMC cycle. Intravenous infusion of motilin (0.3 microg/kg/h) increased the luminal 5-HT content and induced G-MMC and I-MMC. 5-HT(4) antagonists significantly inhibited both G-MMC and I-MMC, while 5-HT(3) antagonists inhibited only G-MMC. It is suggested that the MMC cycle is mediated by a positive feedback mechanism via the interaction between motilin and 5-HT.

Rule-Based Data Tracking Scheme to Reduce the Effects of Creeping

Creeping is a time dependent characteristic and is an intrinsic problem in piezoresistive (e.g., strain gauge) transducers. The creeping behavior of a transducer limits the performance of it in high-resolution applications due to data drifting problem over time. In other words, the effective resolution of the transducer is lower than it should be. A rule-based data tracking scheme is developed in order to reduce the effects of creeping, and preserve the resolution of the transducer. The proposed scheme employs rule-based intelligent system technique and is easy to implement with advanced low cost microcontroller. Testing results of the proposed scheme are also presented in this paper.

Intelligent instrument to facilitate decision making in the evaluation of soil resistance to root penetration

This contribution introduces an instrument for decision-making in agricultural processes based on the measurements and mapping of soil resistance to root penetration. Its development was based on a new and advanced instrumentation tool, enabling in almost real-time to acquire the necessary information for spatial variability analysis of plant root penetration resistance in soils, due to natural or artificial soil compaction processes, i.e., not only for an area of soil but also for a soil profile. The system allows soil resistance assays for both laboratory and agricultural fields. Moreover, the development focused on an intelligent instrumentation concept, as well as a microprobe (30º for the spire angle, 1,6 mm for the base diameter, and 30 mm of total length), with a strain-gage transducer sensor. Results have shown that measurements of soil resistance to plant root penetration can be performed up to the limit of (483.47 ± 0.69) N, with a resolution of 15.4 N. Additionally, the versatility of the system is verified for soil resistance data collection and its interpretation to root plant penetration, since they can be presented in table formats, one-dimensional graphs, two-dimensional and three-dimensional maps. Therefore, this system enables users to obtain a quick interpretation of the soil aggregation state in agricultural areas.

Sympathetic and Parasympathetic Regulation of Rectal Motility in Rats

IntroductionThe colon and rectum are regulated by the autonomic nervous system (ANS). Abnormalities of the ANS are associated with diseases of the colon and rectum while its modulation is a putative mechanism for sacral nerve stimulation. The purpose of this study is to establish a rat model elucidating the role of the efferent ANS on rectal motility. Materials and MethodsRectal motility following transection or stimulation of parasympathetic pelvic nerves (PN) or sympathetic hypogastric nerves (HGN) was measured with rectal strain gauge transducers and quantified as a motility index (MI). Colonic transit was measured 24 hours after transection by calculating the geometric center (GC) of distribution of 51Cr Results and DiscussionTransection of PN and HGN decreased MI to 518 ± 185 g•s (p < 0.05) and increased MI to 5,029 ± 1,954 g•s (p < 0.05), respectively, compared to sham (975 ± 243 g•s). Sectioning of PN and HGN decreased transit with GC = 4.9±0.2 (p < 0.05) and increased transit with GC = 8.1±0.7 (p < 0.02), respectively, compared to sham (GC = 5.8 ± 0.3). Stimulation of PN and HGN increased MI to 831 ± 157% (p < 0.01) and decreased MI to 251 ± 24% (p < 0.05), respectively. ConclusionRectal motility is significantly altered by sectioning or stimulating either HGN or PN. This model may be useful in studying how sacral nerve stimulation exerts its effects and provide insight into the maladies of colonic motility.

Effects on behaviour and rein tension on horses ridden with or without martingales and rein inserts

Unsteady hand position can cause discomfort to the horse, potentially leading to conflict behaviours (CB) such as head tossing or tail lashing. Some instructors feel that martingales or elastic rein inserts can reduce discomfort caused by inexperienced and unsteady hands. Others consider these devices to be inappropriate ‘ crutches’. Four horses and nine riders were tested under three conditions in random order: plain reins, adjustable training martingales (TM), and elasticised rein inserts (RI). Rein-tension data (7 s) and behavioural data (30 s) were collected in each direction. Rein-tension data were collected via strain-gauge transducers. Behavioural data were assessed using an ethogram of defined behaviours. No differences in the number of CB were observed. Mean rein tension for TM was higher than that of RI or controls. Relative to the withers, the head was lower for horses ridden with martingales. Carefully fitted martingales may have a place in riding schools that teach novices.