Determination of Methanol Concentration in Ethanol in Liquid Phase by a Phononic Crystal Mach-Zehnder Interferometer

A practical and portable ultrasonic interferometric sensor to detect methanol concentration in ethanol in the liquid phase is numerically investigated. For high-sensitivity operation, the sensor is designed as a Mach-Zehnder interferometer based on a linear-defect waveguide in a two-dimensional phononic crystal, which consists of square array of cylindrical steel rods in water. The waveguide core comprises polyethylene tubing, impedance-matched with water, filled with either pure ethanol or ethanol-methanol binary mixture, allowing fast replacement of the analyte. Band structure analyses through the finite-element method are carried out to obtain guiding modes at frequencies around 200 kHz. With 50x21 cells with 4.2 mm periodicity, the total sensor area is 210-by-88.2 millimeters, which can be significantly reduced by increasing the operating frequency to megahertz range. The interferometer is constructed via T junctions of the waveguide, which facilitates low-loss equal splitting and recollection of ultrasonic waves. Sample and reference wave paths are constructed by filling polyethylene tubing on the upper and lower halves of the interferometer with the ethanol-methanol mixture and pure ethanol, respectively. Frequency-domain finite-element method simulations reveal that the sensor output is characterized by several transmission peaks, one of which is centered at 203.35 kHz with a full-width at half-maximum of 20 Hz, resulting in a quality factor of 10167. The peak frequency of this peak redshifts at a rate of 7.24 Hz per percent volume fraction change in methanol. The peak shift is linear when the methanol volume fraction is below 10%. Besides, the interferometric sensor has a figure of merit around 0.35. The proposed ultrasonic sensor offers rapid detection of methanol content in ethanol with high sensitivity.

Alive Animal Model for Epilepsy by Intradorsal Striatum Injection of Colchicine

Background Epilepsy is a neural disorder with repeatable seizure attacks. We used the neurotoxin colchicine, which is derived from the plant Colchicum autumnale, to introduce a low cost but the more valuable alive animal model for epilepsy. Materials and Methods Wistar rats weighing 250 to 300 g after intraperitoneal injection of ketamine (100 mg/kg) and xylazine (20 mg/kg) were restrained in the stereotaxic apparatus; they were cannulated in the dorsal striatal area (AP: 0.5 mm; L: 3 mm; V: 3.6 mm). One week later, an injection cannula attached to a 5-µ Hamilton syringe by polyethylene tubing guided 0.05 to 25 μg/rat colchicine in the recovered healthy rats once daily for 4 consecutive days. The control group solely received the saline solution. The behavioral signs of all animals were daily recorded. Finally, the brains of rats under deep euthanasia were collected in 10% formalin and examined histopathologically. The dorsal striatal regions were cut coronally into 3 to 4 µm-thick slices, and then stained with hematoxylin-eosin. They were eventually examined under the light microscope to verify the injection placement or possibility of lesions. All data were analyzed by analysis of variance under α = 0.05. Results Behaviors were quantified based on Racine five-stage scoring and showed the significant epileptic generalized seizures in alive animal treated by intrastriatal injection of colchicine. However, tissue damage was invisible in the target brain area. Conclusion The colchicine, using injection successively into the dorsal striatal region of rat, can create recurring epileptic convulsions in the animal.

Video laryngoscopic oral intubation in rats: a simple and effective method

Endotracheal intubation is a vital component of many rat in vivo experiments to secure the airway and allow controlled ventilation. Even in the hands of experienced researchers, however, the procedure remains technically challenging. The safest and most reliable way for human intubation is by video laryngoscopy. Previous attempts to apply this technique in rodents have been complicated and expensive. We, hereby, describe a novel, noninvasive method to safely intubate rats orally by video laryngoscopy, thus avoiding the need for a surgical tracheostomy. By repurposing a commercially available ear wax removal device, visualization of the rat larynx can be significantly enhanced. Because of its small diameter, integrated illumination, and a powerful camera with adequate focal length, the device has all of the necessary properties for exploring the upper airway of a rat. After identifying the vocal cords by video laryngoscopy, the insertion of an endotracheal tube (a 14G intravenous catheter) into the trachea under constant visual control is facilitated by using PE50 polyethylene tubing as a stylet (Seldinger technique). The procedure has been performed more than 60 times in our laboratory; all intubations were successful on the first attempt, and no adverse events were observed. We conclude that the described procedure is a simple and effective way to intubate a rat noninvasively, using inexpensive and commercially available equipment.

Guava moth (Coscinoptycha improbana) mating disruption using Asian peach moth (Carposina sasakii) pheromone dispensers

Guava moth has now been recorded as far south as Auckland on fruit trees since first being detected in feijoa at Ahipara in 1997 The use of insecticides to control this internal fruit pest is not a viable option for growers To develop the basis for an alternative control tactic using mating disruption smallplot trials were carried out in a macadamia nut orchard using an existing polyethylene tubing pheromone dispenser used in Japan containing pheromone of the related Asian peach moth (Carposina sasakii) Male moths were significantly disrupted from locating pheromone traps (as a surrogate for female moths) using three pheromone dispensers in a single tree and also using one dispenser per tree in a plot of nine trees In a trial investigating the effect of height on trap catch the largest catch was at 3 m near the top of the canopy Aspects of guava moth biology were also investigated in the laboratory larval period in early fallen macadamia nuts pupa period at ambient autumn temperatures adult longevity with water or 10 honey solution compared to no food/water size range and sex ratio of male and female moths