A forceful upper jaw facilitates picking-based prey capture: biomechanics of feeding in a butterflyfish,Chaetodon trichrous

Biomechanical models of feeding mechanisms elucidate how animals capture food in the wild, which, in turn, expands our understanding of their fundamental trophic niche. However, little attention has been given to modeling the protrusible upper jaw apparatus that characterizes many teleost species. We expanded existing biomechanical models to include upper jaw forces using a generalist butterflyfish, Chaetodon trichrous (Chaetodontidae) that produces substantial upper jaw protrusion when feeding on midwater and benthic prey. Laboratory feeding trials for C. trichrous were recorded using high-speed digital imaging; from these sequences we quantified feeding performance parameters to use as inputs for the biomechanical model. According to the model outputs, the upper jaw makes a substantial contribution to the overall forces produced during mouth closing in C. trichrous. Thus, biomechanical models that only consider lower jaw closing forces will underestimate total bite force for this and likely other teleost species. We also quantified and subsequently modeled feeding events for C. trichrous consuming prey from the water column versus picking attached prey from the substrate to investigate whether there is a functional trade-off between prey capture modes. We found that individuals of C. trichrous alter their feeding behavior when consuming different prey types by changing the timing and magnitude of upper and lower jaw movements and that this behavioral modification will affect the forces produced by the jaws during prey capture by dynamically altering the lever mechanics of the jaws. In fact, the slower, lower magnitude movements produced during picking-based prey capture should produce a more forceful bite, which will facilitate feeding on benthic attached prey items, such as corals. Similarities between butterflyfishes and other teleost lineages that also employ picking-based prey capture suggest that a suite of key behavioral and morphological innovations enhances feeding success for benthic attached prey items.     

Effect of intrahippocampal administration of anti-melanin-concentrating hormone on spatial food-seeking behavior in rats

Melanin-concentrating hormone (MCH) is a hypothalamic peptide that plays a critical role in the regulation of food intake and energy metabolism. In this study, we investigated the potential role of dense hippocampal MCH innervation in the spatially oriented food-seeking component of feeding behavior. Rats were trained for eight sessions to seek food buried in an arena using the working memory version of the food-seeking behavior (FSB) task. The testing day involved a bilateral anti-MCH injection into the hippocampal formation followed by two trials. The anti-MCH injection did not interfere with the performance during the first trial on the testing day, which was similar to the training trials. However, during the second testing trial, when no food was presented in the arena, the control subjects exhibited a dramatic increase in the latency to initiate digging. Treatment with an anti-MCH antibody did not interfere with either the food-seeking behavior or the spatial orientation of the subjects, but the increase in the latency to start digging observed in the control subjects was prevented. These results are discussed in terms of a potential MCH-mediated hippocampal role in the integration of the sensory information necessary for decision-making in the pre-ingestive component of feeding behavior.     

Synthesis,characterization and thermoluminescence studies of Mn‐doped ZnS nanoparticles

ZnS:Mn nanoparticles were prepared by a chemical precipitation method and characterized by X‐ray diffraction (XRD), field emission gun scanning electron microscope (FEGSEM), and high resolution transmission electron microscopy (HRTEM). Capping agent (mercaptoethanol) concentrations used were 0 M, 0.005 M, 0.01 M, 0.015 M, 0.025 M, 0.040 M, and 0.060 M, and resulted in nanoparticles sizes of 2.98 nm, 2.9 nm, 2.8 nm, 2.7 nm, 2.61 nm, 2.2 nm and 2.1 nm, respectively. The thermoluminescence (TL) glow curve was recorded by heating the sample exposed to UV‐radiation, at a fixed heating rate 1°C sec^–1. The TL intensity initially increased with temperature, attained a peak value I_m for a particular temperature, and then decreased with further increase in temperature. The peak TL intensity increased with decreasing nanoparticle size, whereas the temperature corresponding to the peak TL intensity decreased slightly with reducing nanocrystal size. As a consequence of increase in surface‐to‐volume ratio and increased carrier recombination rates, the TL intensity increased with decreasing nanoparticle size. It was found that, whereas activation energy slightly decreased with decreasing nanoparticle size, the frequency factor decreased significantly with reduction in nanoparticle size. Copyright © 2015 John Wiley & Sons, Ltd.     

Wide‐field optical property mapping and structured light imaging of the esophagus with spatial frequency domain imaging

As the incidence of esophageal adenocarcinoma continues to rise, there is a need for improved imaging technologies with contrast to abnormal esophageal tissues. To inform the design of optical technologies that meet this need, we characterize the spatial distribution of the scattering and absorption properties from 471 to 851 nm of eight resected human esophagi tissues using Spatial Frequency Domain Imaging. Histopathology was used to categorize tissue types, including normal, inflammation, fibrotic, ulceration, Barrett's Esophagus and squamous cell carcinoma. Average absorption and reduced scattering coefficients of normal tissues were 0.211 ± 0.051 and 1.20 ± 0.18 mm^?1, respectively at 471 nm, and both values decreased monotonically with increasing wavelength. Fibrotic tissue exhibited at least 68% larger scattering signal across all wavelengths, while squamous cell carcinoma exhibited a 36% decrease in scattering at 471 nm. We additionally image the esophagus with high spatial frequencies up to 0.5 mm^?1 and show strong reflectance contrast to tissue treated with radiation. Lastly, we observe that esophageal absorption and scattering values change by an average of 9.4% and 2.7% respectively over a 30 minute duration post‐resection. These results may guide system design for the diagnosis, prevention and monitoring of esophageal pathologies.      

A modified resonant recognition model to predict protein-protein interaction

Proteins are fundamental components of all living cells and the protein-protein interaction plays an important role in vital movement. This paper briefly introduced the original Resonant Recognition Model (RRM), and then modified it by using the wavelet transform to acquire the Modified Resonant Recognition Model (MRRM). The key characteristic of the new model is that it can predict directly the protein-protein interaction from the primary sequence, and the MRRM is more suitable than the RRM for this prediction. The results of numerical experiments show that the MRRM is effective for predicting the protein-protein interaction. Translated from Journal of Shanghai University (Natural Science), 2006, 12(1): 69–73 [译自: 上海大学学报(自然科学版)]     

The pollination efficiency of a pollinator depends on its foraging strategy,flowering phenology,and the flower characteristics of a plant species

Honey bees and stingless bees are generalist visitors of several wild and cultivated plants. They forage with a high degree of floral fidelity and thereby help in the pollination services of those plants. We hypothesized that pollination efficiency might be influenced by flowering phenology, floral characteristics, and resource collection modes of the worker bees. In this paper, we surveyed the foraging strategies of honey bees (Apis cerana, Apis dorsata, and Apis florea) and stingless bees (Tetragonula iridipennis) concerning their pollination efficiencies. Bees showed different resource gathering strategies, including legitimate (helping in pollination as mixed foragers and specialized foragers) and illegitimate (serving as nectar robbers and pollen thieves) types of flower visitation patterns. Foraging strategies are influenced by the shape of flowers, the timing of the visitation, floral richness, and bee species. Honey bees and stingless bees mainly acted as legitimate visitors in most plants studied. Sometimes honey bees served as nectar robbers in tubular flowers and stingless bees as pollen thieves in large-sized flowers. Among the legitimate categories, mixed foragers have a comparatively lower flower visitation rate than the specialized nectar and pollen foragers. However, mixed foragers have greater abundance and higher values of the single-visit pollination efficiency index (PEi) than nectar and pollen foragers. The value of the combined parameter ‘importance in pollination (PI)’ was thus higher in mixed foragers than in nectar and pollen foragers.     

The use of natural language to communicate the perception of vibrotactile stimuli

This study explores the subjective use of adjectives to verbally communicate vibrotactile stimulation across multiple frequencies. In total, nine different vibrotactile stimulus frequencies (10–300?Hz) were utilized, and subjective evaluation methods, which involved adjectives, were used to assess the sensory representations of the participants (18 healthy male participants; mean age, 22.9 years; standard deviation, 3.5). Sensory terms such as ‘slow,’ ‘protruding,’ and ‘thick’ were used as representative expressions to describe low-frequency (10–100?Hz) vibrotactile stimulations, while ‘fast,’ ‘shallow,’ and ‘tickly’ were used to describe high-frequency (225–300?Hz) vibrotactile stimulations. At the frequencies of 150 and 200?Hz, no characteristic word was found because there was no difference in subjective evaluation scores from other low or high frequencies. The results suggest that vibrotactile stimulation at different frequencies induce diverse sensory representations, owing to not only the motion and shape of the stimuli but also the subjective responses of the perceivers. The results of this study could be utilized in developing affective haptic devices in the future.     

The function of extrafloral nectaries in the pollination and reproduction of Sambucus javanica

Sambucus javanica is a perennial herb with extrafloral nectaries (EFNs) on its inflorescences. To explore the ecological functions of EFNs, a factorial combination experiment of ant (access or exclusion) and EFNs (with or without) at the plant level was created in two populations. The role of EFNs in the attraction of ants and flying pollinators, the defensive role of ants against foliar herbivores, the effects of ants on pollinator visitation and the effects of ant–pollinator interactions on fruit production in one or both populations were assessed. Ants were common on the ant-access plants with EFNs, but absent from the ant-access plants without EFNs. Foliar herbivory was independent of ant and EFN treatments and their interactions. The visitation frequency of flying pollinators (honeybees and syrphid flies) and fruit set were significantly higher for plants with EFNs than plants without EFNs, but were not affected by ant treatments or their interactions with EFN treatments. These results suggest that EFNs in S. javanica attracted both ants and flying pollinators, but ants did not present a defensive role against herbivores, did not deter flying pollinators from visiting inflorescences and had no effects on fruit production. In addition, ants were not significant pollen vectors.