505 research outputs found
The Yrast Spectra of Weakly Interacting Bose-Einstein Condensates
The low energy quantal spectrum is considered as a function of the total
angular momentum for a system of weakly interacting bosonic atoms held together
by an external isotropic harmonic potential. It is found that besides the usual
condensation into the lowest state of the oscillator, the system exhibits two
additional kinds of condensate and associated thermodynamic phase transitions.
These new phenomena are derived from the degrees of freedom of "partition
space" which describes the multitude of different ways in which the angular
momentum can be distributed among the atoms while remaining all the time in the
lowest state of the oscillator
The Association of Tetrameric Acetylcholinesterase with ColQ Tail: A Block Normal Mode Analysis
Acetylcholinesterase (AChE) rapidly hydrolyzes acetylcholine in the neuromuscular junctions and other cholinergic synapses to terminate the neuronal signal. In physiological conditions, AChE exists as tetramers associated with the proline-rich attachment domain (PRAD) of either collagen-like Q subunit (ColQ) or proline-rich membrane-anchoring protein. Crystallographic studies have revealed that different tetramer forms may be present, and it is not clear whether one or both are relevant under physiological conditions. Recently, the crystal structure of the tryptophan amphiphilic tetramerization (WAT) domain of AChE associated with PRAD ([WAT](4)PRAD), which mimics the interface between ColQ and AChE tetramer, became available. In this study we built a complete tetrameric mouse [AChE(T)](4)–ColQ atomic structure model, based on the crystal structure of the [WAT](4)PRAD complex. The structure was optimized using energy minimization. Block normal mode analysis was done to investigate the low-frequency motions of the complex and to correlate the structure model with the two known crystal structures of AChE tetramer. Significant low-frequency motions among the catalytic domains of the four AChE subunits were observed, while the [WAT](4)PRAD part held the complex together. Normal mode involvement analysis revealed that the two lowest frequency modes were primarily involved in the conformational changes leading to the two crystal structures. The first 30 normal modes can account for more than 75% of the conformational changes in both cases. The evidence further supports the idea of a flexible tetramer model for AChE. This model can be used to study the implications of the association of AChE with ColQ
Volatile Component Analysis of Michelia alba Leaves and Their Effect on Fumigation Activity and Worker Behavior of Solenopsis invicta
Volatile compounds from mashed (fresh, fallen, and dried) leaves ofMichelia alba were collected via solid-phase microextraction and werethen identified via gas chromatography-mass spectrometry. The resultsshowed that linalool was the dominant component in different leaves,together with caryophyllene, β-elemene, and selinene, the contents ofwhich vary across the samples. The fumigation bioassay results showedthat the volatiles from M. alba leaves exhibited insecticidal activity againstred imported fire ant workers, and the mortality of workers could reachup to 100% after the fallen leaves were treated for 16 h. Mashed freshleaves could effectively reduce the aggregation and drinking ability ofworkers. The volatile substances released from the mashed leaves mightkill the ants, or affect their behavior and weaken the activity by interferingtransmit information between ants. A comprehensive consideration ofthe economic and ecological value of M. alba shows that fallen leavesmight be a good resource to control red imported fire ant
Fuzzy Sampled-Data Control for Synchronization of T-S Fuzzy Reaction-Diffusion Neural Networks with Additive Time-Varying Delays
Fabrication of a novel hierarchical fibrous scaffold for breast cancer cell culture
Supplementary data to this article can be found online at https://doi.org/10.1016/j.polymertesting.2019.106107.Scaffolds combining nano- and submicro-fibers closely mimicking extracellular matrix (ECM) have been poorly exploited for in vitro cancer cell culture. Herein, a combined electrospinning and modified in situ biosynthesis method has been developed to fabricate a novel scaffold consisting of bacterial cellulose (BC) nanofibers and electrospun cellulose acetate (CA) submicrofibers to mimic the fibrillar structure of natural ECM. The CA/BC nano/submicrofibrous scaffold was characterized by scanning electron microscopy (SEM), mechanical strength tests, porosity measurements, and cell studies using the MCF-7 breast cancer cells. In addition, the sensitivity of the cancer cells seeded in the CA/BC nano/submicrofibrous scaffold to an anticancer drug was assessed. It was found that the CA/BC scaffold exhibited an interconnected porous structure in which BC nanofibers penetrated into the submicrofibrous CA scaffold. Such sophisticated structure was responsible for the improved mechanical properties of CA/BC scaffold over the ones obtained using a single kind of fibers. More importantly, the CA/BC scaffold showed improved cell adhesion, migration, and proliferation over single BC or CA scaffold. Finally, cells grown on CA/BC scaffold exhibited a greater doxorubicin resistance than those on single CA or BC scaffold. The results suggest that the CA/BC nano/submicrofibrous scaffold has potential for application in in vitro tumor model for the study of cancer progression and drug screening.This work was supported by the Key Project of Natural Science Foundation of Jiangxi Province (Grant no. 20161ACB20018), the National Natural Science Foundation of China (Grant nos. 31870963,
31660264, and 51572187), the Youth Science Foundation of Jiangxi Province (Grant no. 20181BAB216010), and the Science and Technology Research Project of Jiangxi Education Department (Grant
no. GJJ180348).info:eu-repo/semantics/publishedVersio
The prevalence of adverse reactions among individuals with three-dose COVID-19 vaccination
Background: Considering the adverse reactions to vaccination against coronavirus disease 2019 (COVID-19), some people, particularly the elderly and those with underlying medical conditions, are hesitant to be vaccinated. This study aimed to explore the prevalence of adverse reactions and provide direct evidence of vaccine safety, mainly for the elderly and people with underlying medical conditions, to receive COVID-19 vaccination. Methods: From 1st March to 30th April 2022, we conducted an online survey of people who had completed three doses of COVID-19 vaccination by convenience sampling. Adverse reaction rates and 95% confidence intervals were calculated. In addition, conditional logistic regression was used to compare the differences in adverse reactions among the elderly and those with underlying medical conditions with the general population. Results: A total of 3339 individuals were included in this study, of which 2335 (69.9%) were female, with an average age of 32.1 ± 11.4 years. The prevalence of adverse reactions after the first dose of inactivated vaccine was 24.6 % (23.1 – 26.2 %), 19.2 % (17.8 – 20.7 %) for the second dose, and 19.1 % (17.7 – 20.6 %) for the booster dose; among individuals using messenger RNA vaccines, the prevalence was 42.7 % (32.3 – 53.6 %) for the first dose, 47.2 % (36.5 – 58.1 %) for the second dose, and 46.1 % (35.4 – 57.0 %) for the booster dose. Compared with the general population, the prevalence of adverse events did not differ in individuals with underlying medical conditions and those aged 60 and above. Conclusions: For individuals with underlying medical conditions and those aged 60 and above, the prevalence of adverse reactions is similar to that of the general population, which provides a scientific basis regarding vaccination safety for these populations
Responses of soil respiration and its temperature/moisture sensitivity to precipitation in three subtropical forests in southern China
Both long-term observation data and model simulations suggest an increasing chance of serious drought in the dry season and extreme flood in the wet season in southern China, yet little is known about how changes in precipitation pattern will affect soil respiration in the region. We conducted a field experiment to study the responses of soil respiration to precipitation manipulations – precipitation exclusion to mimic drought, double precipitation to simulate flood, and ambient precipitation as control (abbr. EP, DP and AP, respectively) – in three subtropical forests in southern China. The three forest sites include Masson pine forest (PF), coniferous and broad-leaved mixed forest (MF) and monsoon evergreen broad-leaved forest (BF). Our observations showed that altered precipitation strongly influenced soil respiration, not only through the well-known direct effects of soil moisture on plant and microbial activities, but also by modification of both moisture and temperature sensitivity of soil respiration. In the dry season, soil respiration and its temperature sensitivity, as well as fine root and soil microbial biomass, showed rising trends with precipitation increases in the three forest sites. Contrarily, the moisture sensitivity of soil respiration decreased with precipitation increases. In the wet season, different treatments showed different effects in three forest sites. The EP treatment decreased fine root biomass, soil microbial biomass, soil respiration and its temperature sensitivity, but enhanced soil moisture sensitivity in all three forest sites. The DP treatment significantly increased soil respiration, fine root and soil microbial biomass in the PF only, and no significant change was found for the soil temperature sensitivity. However, the DP treatment in the MF and BF reduced soil temperature sensitivity significantly in the wet season. Our results indicated that soil respiration would decrease in the three subtropical forests if soil moisture continues to decrease in the future. More rainfall in the wet season could have limited effect on the response of soil respiration to the rising of temperature in the BF and MF
Looking and Listening: Audio Guided Text Recognition
Text recognition in the wild is a long-standing problem in computer vision.
Driven by end-to-end deep learning, recent studies suggest vision and language
processing are effective for scene text recognition. Yet, solving edit errors
such as add, delete, or replace is still the main challenge for existing
approaches. In fact, the content of the text and its audio are naturally
corresponding to each other, i.e., a single character error may result in a
clear different pronunciation. In this paper, we propose the AudioOCR, a simple
yet effective probabilistic audio decoder for mel spectrogram sequence
prediction to guide the scene text recognition, which only participates in the
training phase and brings no extra cost during the inference stage. The
underlying principle of AudioOCR can be easily applied to the existing
approaches. Experiments using 7 previous scene text recognition methods on 12
existing regular, irregular, and occluded benchmarks demonstrate our proposed
method can bring consistent improvement. More importantly, through our
experimentation, we show that AudioOCR possesses a generalizability that
extends to more challenging scenarios, including recognizing non-English text,
out-of-vocabulary words, and text with various accents. Code will be available
at https://github.com/wenwenyu/AudioOCR
Incorporating graphene oxide into biomimetic nano-microfibrous cellulose scaffolds for enhanced breast cancer cell behavior
Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10570-020-03078-w)
contains supplementary material, which is available to authorized users.The impact of graphene oxide (GO) on normal cells has been widely investigated. However, much less is known on its effect on cancer cells. Herein, GO nanosheets were incorporated into electrospun cellulose acetate (CA) microfibers. The GO-incorporated CA (GO/CA) microfibers were combined with bacterial cellulose (BC) nanofibers via in situ biosynthesis to obtain the nano-microfibrous scaffolds. The GO/CA-BC scaffolds were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The GO/CA-BC scaffolds were used for breast cancer cell culture to evaluate the effect of GO on cancer cell behavior. Fluorescence images revealed large multicellular clusters on the surface of GO/CA-BC scaffolds. Compared to the bare CA-BC scaffold, the GO/CA-BC scaffolds not only showed enhanced mechanical properties but also improved cell proliferation. It is expected that the GO/CA-BC scaffolds would provide a suitable microenvironment for the culture of cancer cells which is necessary for drug screening and cell biology study.This work was supported by National Natural Science Foundation of China (Grant nos. 51572187,
51973058, 31660264, 31870963), the Key Research and Development Program of Jiangxi Province (No.
20192ACB80008), and the Youth Science Foundation of Jiangxi Province (No. 20181BAB216010), and Key Project of Natural Science Foundation of Jiangxi Province (No. 20161ACB20018).info:eu-repo/semantics/publishedVersio
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