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关键词： electronic nose   eNose   nasal air   differential mobility spectrometry   DMS  

摘要： Over the last few decades, breath analysis using electronic nose (eNose) technology has become a topic of intense research, as it is both non-invasive and painless, and is suitable for point-of-care use. To date, however, only a few studies have examined nasal air. As the air in the oral cavity and the lungs differs from the air in the nasal cavity, it is unknown whether aspirated nasal air could be exploited with eNose technology. Compared to traditional eNoses, differential mobility spectrometry uses an alternating electrical field to discriminate the different molecules of gas mixtures, providing analogous information. This study reports the collection of nasal air by aspiration and the subsequent analysis of the collected air using a differential mobility spectrometer. We collected nasal air from ten volunteers into breath collecting bags and compared them to bags of room air and the air aspirated through the device. Distance and dissimilarity metrics between the sample types were calculated and statistical significance evaluated with Kolmogorov-Smirnov test. After leave-one-day-out cross-validation, a shrinkage linear discriminant classifier was able to correctly classify 100% of the samples. The nasal air differed (p < 0.05) from the other sample types. The results show the feasibility of collecting nasal air by aspiration and subsequent analysis using differential mobility spectrometry, and thus increases the potential of the method to be used in disease detection studies.

关键词： neurogenic inflammation   neuropeptide Y   osteoblastic differentiation   periodontal ligament stem cells   substance P  

摘要： Objectives The aims of this study were to investigate neuropeptide receptor expression regulation on STRO-1 +ve periodontal ligament stem cells (PDLSCs) in response to inflammatory cytokines and to investigate a potential osteogenic effect of neuropeptides. Background Nerve fibres innervating the periodontal tissues in humans contain several neuropeptides including neuropeptide Y and substance P. The role of neuropeptide receptors on PDLSCs, including their response to the local inflammatory environment of periodontitis, is currently unknown. Methods A homogenous population of STRO-1 +ve PDLSCs was prepared by immunomagnetic separation of cells obtained by the tissue out-growth method from healthy premolar teeth from a single donor. Regulation of gene expression of the neuropeptide Y Y1 receptor and substance P receptor tachykinin receptor 1 was investigated. A potential osteogenic effect of neuropeptide Y and substance P was also investigated by measuring alkaline phosphatase (ALP) activity, Alizarin red staining and quantifying osteogenic gene expression. Results Treatment of STRO-1 +ve PDLSCs with tumour necrosis factor-alpha or interleukin 1-beta up-regulated the expression of the neuropeptide Y's Y1 receptor, but down-regulated substance P's receptor. Significantly increased ALP activity was observed in STRO-1 +ve PDLSCs treated with neuropeptide Y but not substance P. Further studies showed that neuropeptide Y had a modest osteogenic effect on cells at both a functional level and a gene level. Conclusions Expression of the neuropeptide Y Y1 receptor gene on STRO-1 +ve PDLSCs was sensitive to local inflammatory cytokines. Treatment of cells with neuropeptide Y was found to produce a modest enhanced osteogenic effect.

关键词： TSPO PET   amino acid PET   FET PET   glioma   contrast enhancement   spatial correlation  

摘要： Simple Summary Radiotracers targeting the translocator protein (TSPO) have recently gained substantial interest, since TSPO is overexpressed in malignant gliomas, where it correlates inversely with patient's survival. The high-affinity TSPO PET ligand [F-18]GE180 was found to depict tumor areas with a remarkably high contrast and has been shown to provide non-invasive information on histological tumor grades. Yet, its significance was questioned with the argument, that the high contrast may solely arise from nonspecific accumulation in tissue supplied by leaky vessels. This study aimed to address this question by providing a detailed evaluation of spatial associations between TSPO and amino acid PET with relative contrast enhancement in T1-weighted MRI. The results show that [F-18]GE180 contrast does not reflect a disrupted blood-brain barrier (BBB) only and that multi-modal imaging generates complementary information, which may better depict spatial heterogeneity of tumor biology and may be used to individualize the therapy for each patient. In this study, dual PET and contrast enhanced MRI were combined to investigate their correlation per voxel in patients at initial diagnosis with suspected glioblastoma. Correlation with contrast enhancement (CE) as an indicator of BBB leakage was further used to evaluate whether PET signal is likely caused by BBB disruption alone, or rather attributable to specific binding after BBB passage. PET images with [F-18]GE180 and the amino acid [F-18]FET were acquired and normalized to healthy background (tumor-to-background ratio, TBR). Contrast enhanced images were normalized voxel by voxel with the pre-contrast T1-weighted MRI to generate relative CE values (rCE). Voxel-wise analysis revealed a high PET signal even within the sub-volumes without detectable CE. No to moderate correlation of rCE with TBR voxel-values and a small overlap as well as a larger distance of the hotspots delineated in rCE and TBR-PET images were detected. I

关键词： Alternative oxidase   Antioxidant enzymes   Antimycin A   Salt stress   Drought stress   Cytochrome oxidase   Photosynthesis   Reactive oxygen species (ROS)   Salicylhydroxamic acid ( SHAM )   Oryza sativa   Immunoblotting  

摘要： Drought and salt stresses are two major abiotic stress factors that hamper crop growth and productivity. Three rice cultivars with different sensitivity and tolerance towards abiotic stress were used in the current study. While cultivar Aiswarya is salt- and drought-sensitive, cultivar Vyttila is salt-tolerant and cultivar Vaisakh is droughttolerant. We compared the physiological and biochemical responses of these rice cultivars under salt and drought stress conditions after restricting their cytochrome oxidase (COX) and alternative oxidase (AOX) pathways using antimycin A and salicylhydroxamic acid treatment. Further, changes in their expression of AOX genes and corresponding protein levels were compared and analysed. The sensitive and tolerant rice cultivars subjected to drought and salt stress showed differential responses in physiological and biochemical traits. Whereas Aiswarya showed clear phenotypic differences, such as stunted growth, leaf curling, and loss of greening in leaf tissues, with increase in salt content and progressive drought stress, Vyttila and Vaisakh showed no remarkable changes. Moreover, the drought-tolerant cultivar rehydrated after 10 days of drought exposure, whereas the sensitive variety did not show any rehydration of leaf tissue. The leaves of the tolerant cultivars showed lower reactive oxygen species (ROS) production than that of the sensitive plants under drought and salt stress conditions because of the activation of a stronger antioxidant defence. Although, the restriction of COX and AOX pathways increased the susceptibility of sensitive cultivars, it affected the tolerant varieties moderately. Higher photosynthetic rates, an efficient antioxidant system comprising higher superoxide dismutase, ascorbate peroxidase, and catalase activity along with higher AOX1a gene expression levels during drought and salt stress were observed in tolerant cultivars. The results suggest that an efficient antioxidant system and increased transcript

关键词： Equivalence transformation   Parameter reduction  

摘要： By using the direct method, we obtain the complete classification of equivalence transformations for a class of fifth-order partial differential equation with variable coefficients. The usual and generalized extended equivalence groups of six disjoint normalized subclasses are presented. Furthermore, with the application of equivalence transformations, the number of variable coefficients is reduced and the transformational properties of the gauged subclasses are proposed. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Galacto-oligosaccharides   colonic microbiota   gut function   piglets  

摘要： Recently, we proved that the early-life galacto-oligosaccharides (GOS) intervention could improve the colonic function by altering the bacterial composition in suckling piglets. However, whether the early-life GOS (ELG) intervention could have a long influence on the colonic microbiota and whether the combined ELG and postweaning GOS (PWG) intervention would have an interacting effect on maintaining colonic health in weaning piglets remain to be explored. In this study, we illustrated the differential effects of the ELG and PWG interventions on colonic microbiota and colonic function of weaning piglets. Our results showed that the ELG and PWG interventions decreased the frequency of diarrhea in weaning piglets while the PWG intervention increased colonic indexes. After 16S rRNA gene MiSeq sequencing of the gut bacteria belonging to different colonic niches (mucosa and digesta), the increase in the a-diversity of the colonic mucosal bacteria during PWG intervention was revealed. In addition, we found that both the ELG and PWG interventions enriched the relative abundances of short-chain fatty acid (SCFA) producers in different colonic niches and increased the total SCFA concentration in colonic digesta. These changes selectively modulated the mRNA expression levels of pattern recognition receptors and barrier proteins in the colonic mucosa. Of note, the combined effect of ELG and PWG effectively enhanced colonic SCFA producer enrichment and upregulated the butyrate concentration. Meanwhile, the expression levels of MyD88-NF-kappa B signaling and the proinflammatory cytokines were markedly reduced under the combined effect of ELG and PWG. IMPORTANCE Reducing the disorders of the gut ecosystem is an effective way to relieve weaning stresses of piglets and minimize economic losses in the modem swine industry. To this end, prebiotics have been often added to their diet during the weaning transition. In the present study, we demonstrated that the ELG and PWG interventions

关键词： adaptive evolution   disease susceptibility   Native Mexican populations  

摘要： Native American genetic ancestry has been remarkably implicated with increased risk of diverse health issues in several Mexican populations, especially in relation to the dramatic changes in environmental, dietary, and cultural settings they have recently undergone. In particular, the effects of these ecological transitions and Westernization of lifestyles have been investigated so far predominantly on Mestizo individuals. Nevertheless, indigenous groups, rather than admixed Mexicans, have plausibly retained the highest proportions of genetic components shaped by natural selection in response to the ancientmilieu experienced byMexican ancestors during their pre-Columbian evolutionary history. These formerly adaptive variants have the potential to represent the genetic determinants of some biological traits that are peculiar to Mexican people, as well as a reservoir of loci with possible biomedical relevance. To test such a hypothesis, we used genome-wide genotype data to infer the unique adaptive evolution of Native Mexican groups selected as reasonable descendants of the main pre-Columbian Mexican civilizations. A combination of haplotype-based and gene-network analyses enabled us to detect genomic signatures ascribable to polygenic adaptive traits plausibly evolved by the main genetic clusters ofMexican indigenous populations to cope with local environmental and/or cultural conditions. Some of these adaptations were found to play a role in modulating the susceptibility/resistance of these groups to certain pathological conditions, thus providing new evidence that diverse selective pressures have contributed to shape the current biological and disease-risk patterns of present-day Native and Mestizo Mexican populations.

关键词： Multipartitions   Divisor function   Self-convolution   Congruences   Differential algebra  

摘要： This paper provides elementary proofs for several types of congruences involving multipartitions and self-convolutions of the divisor function. Our computations use differential algebra and Grobner bases, and employ a couple of MAPLE programs available as ancillary files on arXiv. The first results of the paper are Ramanujan-type congruences of the form p*(k) (qn+r) (q) 0 and sigma*(k) (qn+r) (q) 0, where p(n) and sigma(n) are the partition and divisor functions, q > 3 is prime, (q) denotes congruence modulo q, and *(k) denotes kth-order self-convolution. We prove all the valid congruences of this form for q is an element of {5, 7, 11}, including the three famous partition congruences of Ramanujan, and an exceptional one for q = 17. All such multipartition congruences have already been settled in principle (up to a numerical verification) due to Eichhorn and Ono, using modular forms. On the other hand, the majority of the divisor function congruences are new results. We then proceed to search for more general congruences modulo small primes, concerning linear combinations of sigma*(k) (qn + r) for different values of k, as well as weighted convolutions of p(n) and sigma(n) with polynomial weights. The paper ends with a few corollaries and extensions for the divisor function congruences, including proofs for three conjectures of N.C. Bonciocat.

关键词： Polymer synthesis   Stereochemistry   Chemistry/Food Science   general   Analytical Chemistry   Organic Chemistry   Physical Chemistry   Inorganic Chemistry   Biochemistry  

摘要： Chirality and molecular conformation are central components of life: biological systems rely on stereospecific interactions between discrete (macro)molecular conformers, and the impacts of stereochemistry and rigidity on the properties of small molecules and biomacromolecules have been intensively studied. Nevertheless, how these features affect the properties of synthetic macromolecules has received comparably little attention. Here we leverage iterative exponential growth and ring-opening metathesis polymerization to produce water-soluble, chiral bottlebrush polymers (CBPs) from two enantiomeric pairs of macromonomers of differing rigidity. Remarkably, CBPs with conformationally flexible, mirror image side chains show several-fold differences in cytotoxicity, cell uptake, blood pharmacokinetics and liver clearance;CBPs with comparably rigid, mirror image side chains show no differences. These observations are rationalized with a simple model that correlates greater conformational freedom with enhanced chiral recognition. Altogether, this work provides routes to the synthesis of chiral nanostructured polymers and suggests key roles for stereochemistry and conformational rigidity in the design of future biomaterials.

关键词： fatigue crack evaluation   guided wave   convolutional neural network ensemble   time-frequency spectrogram  

摘要： On-line fatigue crack evaluation is crucial for ensuring the structural safety and reducing the maintenance costs of safety-critical systems. Among structural health monitoring (SHM), guided wave (GW)-based SHM has been deemed as one of the most promising techniques. However, the traditional damage index-based method and machine learning methods require manual processing and selection of GW features, which depend highly on expert knowledge and are easily affected by complicated uncertainties. Therefore, this paper proposes a fatigue crack evaluation framework with the GW-convolutional neural network (CNN) ensemble and differential wavelet spectrogram. The differential time-frequency spectrogram between the baseline signal and the monitoring signal is processed as the CNN input with the complex Gaussian wavelet transform. Then, an ensemble of CNNs is trained to jointly determine the crack length. Real fatigue tests on complex lap joint structures were carried out to validate the proposed method, in which several structures were tested preliminarily for collecting the training dataset and a new structure was adopted for testing. The root mean square error of the training dataset is 1.4 mm. Besides, the root mean square error of the evaluated crack length in the testing lap joint structure was 1.7 mm, showing the effectiveness of the proposed method.