A machine learning based method for tracking of simultaneously imaged neural activity and body posture of freely moving maggot.

To understand neural basis of animal behavior, it is necessary to monitor neural activity and behavior in freely moving animal before building relationship between them. Here we use light sheet fluorescence microscope (LSFM) combined with microfluidic chip to simultaneously capture neural activity and body movement in small freely behaving Drosophila larva. We develop a transfer learning based method to simultaneously track the continuously changing body posture and activity of neurons that move together using a sub-region tracking network with a precise landmark estimation network for the inference of target landmark trajectory. Based on the tracking of each labelled neuron, the activity of the neuron indicated by fluorescent intensity is calculated. For each video, annotation of only 20 frames in a video is sufficient to yield human-level accuracy for all other frames. The validity of this method is further confirmed by reproducing the activity pattern of PMSIs (period-positive median segmental interneurons) and larval movement as previously reported. Using this method, we disclosed the correlation between larval movement and left-right asymmetry in activity of a group of unidentified neurons labelled by R52H01-Gal4 and further confirmed the roles of these neurons in bilateral balance of body contraction during larval crawling by genetic inhibition of these neurons. Our method provides a new tool for accurate extraction of neural activities and movement of freely behaving small-size transparent animals.

An Ultra-Broadband Electromagnetic Wave Absorbing ZrB2-Based Ceramic Composite Inspired by Barbule of Peacock.

Broadband electromagnetic wave (EMW) absorbing ceramic materials are highly required for the thermal parts of aerocraft. As members of ultrahigh temperature ceramics, ZrB2-based ceramics have great potential for applications in more extreme environments relative to the currently used silicon-based and oxide-based ceramics. However, ZrB2 is not among the traditional EMW absorbing material candidates due to its high conductivity, which induces the strong reflection of EMW due to the impedance mismatch with free space. Herein, ZrB2-based ceramic with a bionic microstructure inspired by peacock barbules is proposed. Boron nitride nanotubes acting as polarization centers inside the ZrB2-based material cause massive EMW dissipation. The ceramic shows an ultra-broadband absorption of 9.6 GHz (<-10 dB from 8.4 to 18 GHz), almost covering the entire X and Ku bands, superior to the reported ceramics. The polarization centers successfully turn the ZrB2-based ceramic from EMW reflecting material to an excellent EMW absorbing material by the bionic barbule interspersed microstructure. The simulated metamaterial of the ceramic achieves an ultra-broad absorption (lower than -15 dB) in the range of 2-40 GHz. This work provides valuable insights for the development of broadband absorption material for high-temperature environments.

Adaptive behaviors of Drosophila larvae on slippery surfaces.

Friction is ubiquitous but an essential force for insects during locomotion. Insects use dedicated bio-mechanical systems such as adhesive pads to modulate the intensity of friction, providing a stable grip with touching substrates for locomotion. However, how to uncover behavioral adaptation and regulatory neural circuits of friction modification is still largely understood. In this study, we devised a novel behavior paradigm to investigate adaptive behavioral alternation of Drosophila larvae under low-friction surfaces. We found a tail looseness phenotype similar to slipping behavior in humans, as a primary indicator to assess the degree of slipping. We found a gradual reduction on slipping level in wild-type larvae after successive larval crawling, coupled with incremental tail contraction, displacement, and speed acceleration. Meanwhile, we also found a strong correlation between tail looseness index and length of contraction, suggesting that lengthening tail contraction may contribute to enlarging the contact area with the tube. Moreover, we found a delayed adaptation in rut mutant larvae, inferring that neural plasticity may participate in slipping adaptation. In conclusion, our paradigm can be easily and reliably replicated, providing a feasible pathway to uncover the behavioral principle and neural mechanism of acclimation of Drosophila larvae to low-friction conditions.

Adsorption-oxidation of hydrogen sulfide on Fe/walnut-shell activated carbon surface modified by NH3-plasma.

Walnut-shell activated carbon (WSAC) supported ferric oxide was modified by non-thermal plasma (NTP), and the removal efficiency for hydrogen sulfide over Fe/WSAC modified by dielectric barrier discharge (DBD) was significantly promoted. The sample modified for 10min and 6.8kV output (30V input voltage) maintained 100% H2S conversion over a long reaction time of 390min. The surface properties of adsorbents modified by NTP under different conditions were evaluated by the methods of X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) analysis and in-situ Fourier transform infrared spectroscopy (FTIR), to help understand the effect of the NTP treatment. NTP treatment enhanced the adsorption capacity of Fe/WSAC, which could due to the formation of micro-pores with sizes of 0.4, 0.5 and 0.75nm. XPS revealed that chemisorbed oxygen changed into lattice oxygen after NTP treatment, and lattice oxygen is beneficial for H2S oxidation. From the in-situ FTIR result, transformation of the reaction path on Fe/WSAC was observed after NTP modification. The research results indicate that NTP is an effective method to improve the surface properties of the Fe/WSAC catalyst for H2S adsorption-oxidation.

Toward Professionalism of Biobanking in China: A Survey on Working Status, Career Development, Challenges, and Prospects of Biobankers.

Biobanking has become an increasingly important activity to provide resources for medical research support. In China, establishing and maintaining a biobank have been the latest trend in a research hospital. However, biobanking is still an emerging young field in terms of professionalization and professionalism. The development of professionalization in biobanking faces many challenges involving the development of skills, identities, norms, and values associated with becoming part of a professional group. Biobanking professionals (i.e., biobankers) are the most important factor and driving force toward professionalization in biobanking. To better understand biobankers' performance, needs, concerns, and career development, we conducted two comprehensive surveys among biobankers in China in 2019 and 2021, respectively. The questionnaires covered four major areas: (1) basic information and the status of biobankers; (2) job performance evaluation, salary, recognitions, rewards, and so on; (3) occupational training and career development; and (4) challenges and prospects and so on. The surveys revealed that most biobankers in China have positive working attitudes and a high desire for their future career development, but due to the uncertain evaluation mechanisms and promotion routes, etc., the participants were more optimistic about biobanking development compared to the biobanker's career development (77.0% and 57.4% respectively in 2021, p < 0.05). The biobankers expected more training opportunities and salary packages. Because biobankers are an integral factor and driving force to ensure the successful biobanking operation and advancement, the survey data analysis revealed interesting findings and references for the development of professionalism in biobanking. This survey will provide first-hand information to governments, biobank management teams, and the general public to further support, promote, or optimize (1) biobanking operation and sustainability, (2) biobankers' career development, (3) biobank management and quality control, and (4) strategic plans and approaches to establish a higher quality professional team of biobankers.

The cushioning function of woodpecker's jaw apparatus during the pecking process.

Woodpeckers can withstand a fierce impact during pecking without any brain injury. Although directly involved in the whole pecking, the role of the jaw apparatus played in the impact-resistant process of woodpeckers is still not fully clear. We employed finite element analysis, impact tests in vivo, and post-traumatic brain anatomical observation to evaluate the protective function of the jaw apparatus. Forehead impact model and beaks impact without quadrate joints model were selected as control groups. The maximum impact force, the maximum stress of skull, the maximum strain and strain rate of brain were employed as the main parameters for comparison. The simulations showed that: the impact force, the skull's maximum von Mises stress, the brain's maximum principal strain and the principal strain rate increased by 72%, 24%, 148% and 106%, when the forehead rather than beaks were impacted; while they increased by 23%, 74%, 116% and 72% in the beaks impact without quadrate joints model. The results of simulations were supported by the anatomical observation: brain injury was not found after beak impact tests; serious hyperaemia, bleeding, and contra-coup injury were observed after forehead impact tests. This study discovered that the jaw apparatus acted as a cushion during the pecking process and the quadrate bone and joints changed the type of load and prolonged the acting time, which reduced the impact load acted on the skull and brain. This study would provide new inspirations to develop the device for brain protection, bio-inspired structure and material for energy-absorbing.

Deep-learning on-chip light-sheet microscopy enabling video-rate volumetric imaging of dynamic biological specimens.

Volumetric imaging of dynamic signals in a large, moving, and light-scattering specimen is extremely challenging, owing to the requirement on high spatiotemporal resolution and difficulty in obtaining high-contrast signals. Here we report that through combining a microfluidic chip-enabled digital scanning light-sheet illumination strategy with deep-learning based image restoration, we can realize isotropic 3D imaging of a whole crawling Drosophila larva on an ordinary inverted microscope at a single-cell resolution and a high volumetric imaging rate up to 20 Hz. Enabled with high performances even unmet by current standard light-sheet fluorescence microscopes, we in toto record the neural activities during the forward and backward crawling of a 1st instar larva, and successfully correlate the calcium spiking of motor neurons with the locomotion patterns.

Biomechanism of resistance to retinal injury in woodpecker's eyes.

Retinal injury is the most common ocular impairment associated with shaken baby syndrome (SBS), which could lead to vision loss and blindness. However, a woodpecker does not develop retinal hemorrhages or detachment even at a high acceleration of 1,000×g during pecking. To understand the mechanism of retinal injury and its resistance strategy, we put insight into the special ability of the woodpecker to protect the retina against damage under acceleration-deceleration impact. In this study, the structural and mechanical differences on the eyes of the woodpecker and human were analyzed quantitatively based on anatomical observation. We developed finite element eye models of the woodpecker and human to evaluate the dynamic response of the retina to the shaking load obtained from experimental data. Moreover, several structural parameters and mechanical conditions were exchanged between the woodpecker and human to evaluate their effects on retinal injury in SBS. The simulation results indicated that scleral ossification, lack of vitreoretinal attachment, and rotational acceleration-deceleration impact loading in a woodpecker contribute to the resistance to retinal injuries during pecking. The above mentioned special physical structures and mechanical behavior can distribute the high strain in the posterior segment of the woodpecker's retina, which decrease the risk of retinal injury to SBS.