Use of ear tags and injectable transponders for the identification and traceability of pigs from birth to the end of the slaughter line.
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A total of 557 newborn piglets were used to compare eight identification devices, including one plastic ear tag as a control (C, n = 348) and two types of electronic ear tags (E1, n = 106; and E2, n = 103), and five types of injectable transponders (n = 557): small 12-mm (D12, n = 116; and S12, n = 110), medium 23-mm (T23, n = 108), and large (32-mm, T32, n = 115; and 34-mm, S34, n = 108). Injections were made s.c. in the auricle base (n = 248) and intraperitoneally (n = 309) using a new technique. All piglets were identified with two devices, but using electronic ear tags in conjunction with injection in the auricle was avoided on the same pig. Readability of devices was checked during fattening (until 110 kg BW) and slaughtering. On-farm losses were lower for control than for electronic ear tags (C = 1.1%; E1 = 8.8%; and E2 = 44.9%; P < 0.01); the latter also suffered electronic failures (E1 = 5.5%; and E2 = 55.1%; P < 0.001). On-farm losses of transponders injected in the auricle base were greater in large (S34 = 72.5%; and T32 = 46.3%; P < 0.05) than in small transponders (S12 = 19.4%; and D12 = 17.1%), but T23 (29.8%) only differed from S34. Transponder size did not affect on-farm losses for intraperitoneal injections in which only one loss was recorded (0.4%). All ear tags had similar losses during transportation to the slaughterhouse (1.2%), but no losses were observed in injectables. Slaughtering losses did not differ between ear tags (C = 11.2%; and E1 = 6.4%), but apart from losses, 12.8% of E1 failed electronically. Injection site affected losses and breakages during slaughtering (auricle base = 6.4%; and intraperitoneal = 0%), but recovery time did not significantly differ (auricle base = 28.6 s; and intraperitoneal = 18.9 s). Transponders in the auricle base were recovered by sight (30.2%), palpation (27.4%), or by cutting (42.5%). Intraperitoneal transponders were mainly recovered loose in the abdominal cavity (81.4%), whereas 18.6% fell on the floor. As a result, traceability varied significantly (P < 0.05) between control (86.7%) and electronic ear tags (0 to 68.1%) and injectable transponders, with the auricle base (17.8 to 75.0%) having lower values than intraperitoneal (98 to 100%). Intraperitoneal injection was a very effective tool for piglet identification and traceability, ensuring the transfer of information from farm to slaughterhouse. To warrant the use of this technique in practice, transponder recovery requires further investigation. (+info)
Cell-transistor coupling: investigation of potassium currents recorded with p- and n-channel FETs.
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Microelectronic-based biosensors that allow noninvasive measurement of cell activity are in the focus of current developments, however, the mechanisms underlying the cell-transistor coupling are not completely understood. In particular, characteristic properties of the extracellular voltage response such as the waveform and amplitude are not satisfactorily described by electrical circuit models. Here we examine the electrical coupling between a nonmetallized field-effect transistor (FET) and a cell line expressing a voltage-gated EAG K+ channel. The activation kinetics of this channel depends on the voltage pulse protocol and extracellular divalent cations. This feature allows testing, whether the extracellular voltage signal recorded with the FET faithfully tracks the current simultaneously recorded with the patch-clamp technique. We find that the FET signals contain different kinetic components that cannot be entirely explained by equivalent electrical-circuit models. Rather, we suggest that changes in ion concentration in the small cleft between cell and FET may change the surface potential of the FET. This study provides evidence that the electrochemical processes at the cell-transistor interface are complex and that at least two different mechanisms contribute to the shape and amplitude of transistor signals. (+info)
Direct observation of thitherto unobservable quantum phenomena by using electrons.
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Fundamental aspects of quantum mechanics, which were discussed only theoretically as "thought experiments" in the 1920s and 1930s, have begun to frequently show up in nanoscopic regions owing to recent rapid progress in advanced technologies. Quantum phenomena were once regarded as the ultimate factors limiting further miniaturization trends of microstructured electronic devices, but now they have begun to be actively used as the principles for new devices such as quantum computers. To directly observe what had been unobservable quantum phenomena, we have tried to develop bright and monochromatic electron beams for the last 35 years. Every time the brightness of an electron beam improved, fundamental experiments in quantum mechanics became possible, and quantum phenomena became observable by using the wave nature of electrons. (+info)
A molecular switch and electronic circuit modulate catalase activity in catalase-peroxidases.
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The catalase reaction of catalase-peroxidases involves catalase-specific features built into a peroxidase core. An arginine, 20 A from the active-site heme, acts as a molecular switch moving between two conformations, one that activates heme oxidation and one that activates oxoferryl heme reduction by H(2)O(2), facilitating the catalatic pathway in a peroxidase. The influence of the arginine is imparted to the heme through its association with or dissociation from a tyrosinate that modulates reactivity through a Met-Tyr-Trp crosslinked adduct and a pi electron interaction of the heme with the adduct Trp. (+info)
An in vitro comparison of root canal measurement in primary teeth.
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To compare the accuracy of root canal lengths in primary teeth determined by tactile sense, electronic apex locator, conventional radiography, and digital radiography in primary teeth. The study sample consisted of twenty 20 extracted, single-rooted primary teeth. A comparison was made between the working length measurements obtained by tactile sensation, electronic apex locator, conventional film, and digital radiography, using stereomicroscopic measurements to obtain real canal length. The mean readings obtained were 15.91+/-2.06 by tactile measurement, 15.94 94+/-1.42 by apex locator, 16.06+/-1.73 by conventional radiography, and 15.91+/-1.60 by digital radiography. No statistically significant differences were seen between the techniques. (+info)
Miniaturization (0.2 g) and evaluation of attachment techniques of telemetry transmitters.
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We have developed a miniaturized very high frequency (VHF) transmitter design for radio-tagging small animals. The average mass of the circuitry is 0.084 g (range 0.081-0.087), hence, with the smallest power cell, complete tags weigh 0.2 g and have a life of 18-22 days. We further demonstrate that with such small tags the technique of attaching the device to the animal's body strongly affects the effective radiated power, and thus transmission ranges. Ideally the attachment couples the electronics to the animal's body as a ground plane for improved radiation. The transmitter allows the application of radio-tracking to be expanded to new taxa whose spatial behaviour and population dynamics are largely unknown, for example arthropods, reptiles or amphibians. The new design is also suitable for miniature implants and signal modulation with sensors. (+info)
Smart wheelchairs: A literature review.
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Several studies have shown that both children and adults benefit substantially from access to a means of independent mobility. While the needs of many individuals with disabilities can be satisfied with traditional manual or powered wheelchairs, a segment of the disabled community finds it difficult or impossible to use wheelchairs independently. To accommodate this population, researchers have used technologies originally developed for mobile robots to create "smart wheelchairs." Smart wheelchairs have been the subject of research since the early 1980s and have been developed on four continents. This article presents a summary of the current state of the art and directions for future research. (+info)
Electronic surveillance system for monitoring surgical antimicrobial prophylaxis.
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OBJECTIVES: Antimicrobial surgical prophylaxis comprises one third of all antibiotic use in pediatric hospitals and 80% of all antibiotic use in surgery. Previous studies reported that antimicrobial surgical prophylaxis is often inconsistent with recommended guidelines. An electronic surveillance system was developed to measure antimicrobial utilization and to identify opportunities to improve and monitor the administration of antibiotics for surgical prophylaxis. METHODS: A retrospective cohort study was conducted on patients with selected inpatient surgical procedures performed from May 1999 to April 2000 at 4 US children's hospitals. International Classification of Diseases, Ninth Revision surgical procedure codes were divided into clean or unclean categories, and an electronic surveillance system was designed using antibiotic and microbiologic culture utilization data to measure appropriate antimicrobial use associated with the surgical procedure. A medical chart review was conducted to validate the electronic system. RESULTS: Ninety percent of cases were classified properly by the electronic surveillance system as confirmed by medical chart review. Surgical antibiotic prophylaxis was not in accordance with the American Academy of Pediatrics (AAP) guidelines for almost half of all procedures. Prolonged antimicrobial administration in clean surgical procedures was the most frequent deviation from guidelines. Statistical differences between the index hospital and the comparison hospitals reflect both over- and underutilization of surgical prophylaxis with significant opportunity to improve prophylaxis for all hospitals. CONCLUSIONS: Antimicrobial surgical prophylaxis at the children's hospitals studied is not always consistent with published AAP guidelines. This electronic surveillance system provides a rapid, reproducible, and validated tool to measure easily the efforts to improve adherence to AAP surgical prophylaxis guidelines. (+info)