Spontaneous phase oscillation induced by inertia and time delay

We consider a system of coupled oscillators with finite inertia and time-delayed interaction, and investigate the interplay between inertia and delay both analytically and numerically. The phase velocity of the system is examined; revealed in numerical simulations is emergence of spontaneous phase oscillation without external driving, which turns out to be in good agreement with analytical results derived in the strong-coupling limit. Such self-oscillation is found to suppress synchronization and its frequency is observed to decrease with inertia and delay. We obtain the phase diagram, which displays oscillatory and stationary phases in the appropriate regions of the parameters.Comment: 5 pages, 6 figures, to pe published in PR

Evaluation of cognitive function in adult rhesus monkeys using the finger maze test

In research on cognitive function, the use of experimental animals is essential for the study of human cognitive processes and mechanisms. Furthermore, non-human primates are necessary for understanding higher cognitive functions in humans. However, there are few cognitive function tests available for non-human primates, Thus, we modified a finger maze test for application to non-human primates. In this study, we assessed learning and memory in 12 adult rhesus monkeys using a finger maze test that was developed to assess cognitive functions in captive non-human primates. The monkeys were trained with moving rewards indicating the correct direction, which allowed the monkeys to obtain the reward. Following training, subjects completed a learning trial and a memory trial two months later. Although the time required for training varied among the monkeys, 11 out of 12 monkeys completed the training and achieved a high success rate in the learning trial as well as in the memory trial conducted 2 months later. This is the first study to apply the finger maze test to adult rhesus monkeys. The finger maze test enabled us to assess learning and memory in several adult rhesus monkeys simultaneously

KACC: An identification and characterization for microbial resources in Korea

Korean Agricultural Culture Collection (KACC) is an authorized organizer and the official depository for microbial resources in Korea. The KACC has developed a web-based database system to provide integrated information about microbial resources. It includes not only simple text information onindividual microbe but also morphological images and DNA sequence data for the strain. The KACC now provides the characterization information which maintains 7,433 cultures of microorganisms including 2,687 strains of bacteria, 3535 fungi, 476 actinomycetes, 64 yeasts, and 671 others (mushrooms, gene clones, etc)

Theory of magnetic field-induced metaelectric critical end point in BiMn2_2O5_5

A recent experiment on the multiferroic BiMn$_2$O$_5$ compound under a strong applied magnetic field revealed a rich phase diagram driven by the coupling of magnetic and charge (dipolar) degrees of freedom. Based on the exchange-striction mechanism, we propose here a theoretical model with the intent to capture the interplay of the spin and dipolar moments in the presence of a magnetic field in BiMn$_2$O$_5$. Experimentally observed behavior of the dielectric constants, magnetic susceptibility, and the polarization is, for the most part, reproduced by our model. The critical behavior observed near the polarization reversal $(P=0)$ point in the phase diagram is interpreted as arising from the proximity to the critical end point.Comment: Theory; relevant experiment uploaded as arXiv:0810.190

Active Immunization with Extracellular Vesicles Derived from Staphylococcus aureus Effectively Protects against Staphylococcal Lung Infections, Mainly via Th1 Cell-Mediated Immunity

Staphylococcus aureus is an important pathogenic bacterium that causes various infectious diseases. Extracellular vesicles (EVs) released from S. aureus contain bacterial proteins, nucleic acids, and lipids. These EVs can induce immune responses leading to similar symptoms as during staphylococcal infection condition and have the potential as vaccination agent. Here, we show that active immunization (vaccination) with S. aureus-derived EVs induce adaptive immunity of antibody and T cell responses. In addition, these EVs have the vaccine adjuvant ability to induce protective immunity such as the up-regulation of co-stimulatory molecules and the expression of T cell polarizing cytokines in antigen-presenting cells. Moreover, vaccination with S. aureus EVs conferred protection against lethality induced by airway challenge with lethal dose of S. aureus and also pneumonia induced by the administration of sub-lethal dose of S. aureus. These protective effects were also found in mice that were adoptively transferred with splenic T cells isolated from S. aureus EV-immunized mice, but not in serum transferred mice. Furthermore, this protective effect of S. aureus EVs was significantly reduced by the absence of interferon-gamma, but not by the absence of interleukin-17. Together, the study herein suggests that S. aureus EVs are a novel vaccine candidate against S. aureus infections, mainly via Th1 cellular response.111814Ysciescopu

Validation of Submaximal Step Tests and the 6-Min Walk Test for Predicting Maximal Oxygen Consumption in Young and Healthy Participants.

Background: This study aimed to test the validity of three different submaximal tests (i.e., 3-min step test with 20.3-cm step box height (3MST20), 3-min step test with 30-cm step box height (3MST30), and 6-min walk test (6MWT)) in estimating maximal oxygen consumption (VO2max) in young and healthy individuals. Methods: The 3MST20, 3MST30, 6MWT, as well as the cardiopulmonary exercise test (CPET) were performed in 73 participants (37 men and 36 women; mean age: 30.8 ± 9.3 years). All participants visited the clinic three times in a random order for anthropometric measurements, three submaximal tests, and the VO2max test. Multiple linear regression analyses were conducted to construct the VO2max prediction equations for each submaximal test. Results: The prediction equations developed based on multiple regression analyses for each submaximal tests were as follows: 3MST20: VO2max = 86.0 - 10.9 × sex (male = 1, female = 2) - 0.4 × age - 0.1 × weight - 0.1 × heart rate recovery at 30 s (HRR30s); 3MST30: VO2max = 84.5 - 10.2 × sex (male = 1, female = 2) - 0.4 × age - 0.1 × weight - 0.1 × HRR30s; and 6MWT: VO2max = 61.1 - 11.1 × sex (male = 1, female = 2) - 0.4 × age - 0.2 × weight - 0.2 × (distance walked·10-1). The estimated VO2max values based on formulated equations were 37.0 ± 7.9, 37.3 ± 7.6, and 36.9 ± 7.9 mL∙kg-1∙min-1 derived from the 3MST20, 3MST30, and 6MWT, respectively. These estimated VO2max values were not significantly different from the measured VO2max value, 37.3 mL∙kg-1∙min-1. The estimated VO2max based on the 3MST20, 3MST30, and 6MWT results explained 73.4%, 72.2%, and 74.4% of the variances in the measured VO2max (p < 0.001), respectively. Conclusions: The 3MST20, 3MST30, and 6MWT were valid in estimating VO2max in relatively young and healthy Asian individuals

Autonomous stochastic resonance in fully frustrated Josephson-junction ladders

We investigate autonomous stochastic resonance in fully frustrated Josephson-junction ladders, which are driven by uniform constant currents. At zero temperature large currents induce oscillations between the two ground states, while for small currents the lattice potential forces the system to remain in one of the two states. At finite temperatures, on the other hand, oscillations between the two states develop even below the critical current; the signal-to-noise ratio is found to display array-enhanced stochastic resonance. It is suggested that such behavior may be observed experimentally through the measurement of the staggered voltage.Comment: 6 pages, 11 figures, to be published in Phys. Rev.

Robust Crop and Weed Segmentation under Uncontrolled Outdoor Illumination

An image processing algorithm for detecting individual weeds was developed and evaluated. Weed detection processes included were normalized excessive green conversion, statistical threshold value estimation, adaptive image segmentation, median filter, morphological feature calculation and Artificial Neural Network (ANN). The developed algorithm was validated for its ability to identify and detect weeds and crop plants under uncontrolled outdoor illuminations. A machine vision implementing field robot captured field images under outdoor illuminations and the image processing algorithm automatically processed them without manual adjustment. The errors of the algorithm, when processing 666 field images, ranged from 2.1 to 2.9%. The ANN correctly detected 72.6% of crop plants from the identified plants, and considered the rest as weeds. However, the ANN identification rates for crop plants were improved up to 95.1% by addressing the error sources in the algorithm. The developed weed detection and image processing algorithm provides a novel method to identify plants against soil background under the uncontrolled outdoor illuminations, and to differentiate weeds from crop plants. Thus, the proposed new machine vision and processing algorithm may be useful for outdoor applications including plant specific direct applications (PSDA)

Effects of delayed remote ischemic preconditioning on peri-operative myocardial injury in patients undergoing cardiac surgery - A randomized controlled trial

BACKGROUND: Remote ischemic preconditioning (RIPC) has two time windows for organ protection: acute and delayed. Previous studies have mainly focused on the acute time window to evaluate organ protection by RIPC. We evaluated myocardial protection by delayed RIPC in adult patients undergoing cardiac surgery. METHODS: A total of 160 adult patients undergoing cardiac surgery with cardiopulmonary bypass were randomized to receive either delayed RIPC (four cycles of 5 min of ischemia followed by 5 min of reperfusion by inflation to 200 mm Hg and deflation of a blood pressure cuff on the upper arm) or the control treatment 24–48 h before surgery. The primary endpoint was post-operative troponin I levels serially measured for 72 h. Secondary endpoints included post-operative serum creatinine levels, acute kidney injury, and composite complications. RESULTS: There were no significant differences in post-operative troponin I values. The incidence of acute kidney injury, defined by the Acute Kidney Injury Network staging system, was lower in the delayed RIPC group compared to the control group (30.0% vs. 47.5%; relative risk, 0.768; 95% confidence interval, 0.599–0.985; p = 0.023). Moreover, the occurrence of composite complications was lower in the delayed RIPC group compared with the control group (65.0% vs. 81.3%; relative risk, 0.536; 95% confidence interval, 0.311–0.924; p = 0.020). CONCLUSIONS: While RIPC did not provide cardioprotective effects in patients undergoing cardiac surgery, it appeared to reduce acute kidney injury, as well as the rate of composite complications