Thermal treatment using microwave irradiation for the phytosanitation of Xylella fastidiosa in pecan graftwood.

Pecan bacterial leaf scorch caused by Xylella fastidiosa is an emerging disease for the U.S. and international pecan industries and can be transmitted from scion to rootstock via grafting. With the expanse of global transportation and trade networks, phytosanitation is critical for reducing the spread of economically significant pathogens, such as X. fastidiosa. We developed and evaluated thermal treatments using microwave irradiation and microwave absorbers [sterile deionized water (dH2O) and carbon nanotubes (CNTs)] as novel disinfectant methods for remediating X. fastidiosa in pecan scions. Partial submergence of scions in dH2O or CNT dispersions resulted in the transport of microwave absorbers in the xylem tissue via transpiration but did not compromise plant health. The microwave absorbers effectively transferred heat to the scion wood to reach an average temperature range of 55-65°C. Microwave radiation exposure for 6 sec (3 sec for two iterations) of CNT- or dH2O-treated scions reduced the frequency of X. fastidiosa-positive in pecan scions without negatively affecting plant viability when compared to the control group (dH2O-treated with no microwave). The efficacy of the new thermal treatments based on microwave irradiation was comparable to the conventional hot-water treatment (HWT) method, in which scions were submerged in 46°C water for 30 min. Microwave irradiation can be employed to treat X. fastidiosa-infected scions where the conventional HWT treatment is not feasible. This study is the first report to demonstrate novel thermal treatment methods based on the microwave irradiation and microwave absorbers of dH2O and CNT as an application for the phytosanitation of xylem-inhabiting bacteria in graftwood.

Experimental study for the reproduction of sudden unintended acceleration incidents.

A few cases of the sudden unintended acceleration have been reported over the last few years [1-11] and some of them seemed to be somewhat related to an electronic throttle control (ETC) system [11,12]. In this experimental study, efforts were made to reproduce the cases of sudden unintended acceleration possibly related to the ETC. Typically, an ETC of the engine is managed based on signals from airflow sensor, throttle position sensor and acceleration pedal sensor. With this typical sensor configuration in mind, these sensor signals were checked for noise levels. However, none of them showed any clear relationship with the sudden unintended acceleration mainly due to the robustness of the ETC logic software. As an alternative approach, supply voltage to an engine control unit (ECU) was tempered intentionally to observe any clues for the incidents. The observed results with the supply voltage drop and fluctuation tests were rather astonishing. The throttle valve position went all the way up to 100% for around one second when the battery voltage plunged down to 7V periodically despite that the acceleration pedal position was kept steady. As an effort to confirm the case, multiple tries were made systematically on a chassis dynamometer as well as on the test road. In this paper, detailed procedures and findings are reported accordingly.

Biomechanical analysis of biphasic distribution of skull injury in falls from height.

Fall from height is one of the most common ways of suicide in Korea. Skull fractures are typically accompanied with these cases, but several autopsy cases show absence of skull fracture even with serious body injuries including sternal and vertebral fracture. The mechanism of this pattern of injury can be explained by impact of facial part on chest or abdomen when the back of the body touches the ground first. We tried to figure out the relevance of this pattern of injury to the height of fall using a computer simulation tool (MADYMO 7.5). For this experiment, a condition of initial pose was limited to leaning forward. The simulation showed that when the body rotated forward, the body parts which got injured by the ground depended on the height of fall. For relatively lower height, head got injured, but as the height was set higher, the point of first impact area changed to the back, hip and then legs. When the body struck first around hip area on supine position, the impact made forceful flexion of lumbar, thoracic and cervical vertebrae, leading to folding the body in two, which resulted in collision between the part of face and the anterior part of body. Through the current investigation, it was explained that the biphasic distribution of the number of head injury cases versus the height distribution was attributed to the forward rotation of the body during the fall.

Six cases of bacterial infection in porous orbital implants.

BACKGROUND: We present 6 cases of bacterial infection that developed after porous orbital implant surgery. CASES: Five patients with hydroxyapatite implants showed lid swelling, discharge, and suppurative granuloma 14 days to 3 years after surgery. The hydroxyapatite implants were removed 14 days to 41 months postoperatively, and synthetic porous polyethylene orbital implants were inserted. Thick discharge and conjunctival melting was noted 14 months after primary Medpor implant surgery in the sixth patient, and the infection was controlled by medical therapy. OBSERVATIONS: The culture of specimens removed with swabs from the conjunctiva of patients and from the hydroxyapatite implants showed growth of Staphylococcus aureus, Staphylococcus epidermidis, alpha-hemolytic streptococcus and peptostreptococcus in 4 patients, whereas Streptococcus pyogenes were cultured from the conjunctiva in the Medpor implant patient. Culture for the remaining patient was negative . CONCLUSIONS: If there is continuous pain, injection, and discharge after porous implant insertion, bacterial infection in the implant should be considered immediately. Systemic antibiotics and topical eye drops should be administered without delay. If no improvement is observed, the implant should be removed and a different approach must be considered.