798 research outputs found

    The impact of nutritional quality and gut bacteria on the fitness of Bactrocera minax (Diptera: Tephritidae)

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    To examine how nutritional quality and resident gut bacteria interplay in improving the fitness of an oligophagous fruit fly, Bactrocera minax, artificial sucrose diets and full diets (sucrose, tryptone and yeast extract) were fed to flies with and without antibiotic supplementation. Furthermore, Klebsiella oxytoca and Citrobacter freundii were supplemented to sucroseonly diets. Flies were maintained in the laboratory and the fitness parameters, male and female longevity, number of copulations and female fecundity, were recorded. Full diet without bacterial depletion significantly increased fecundity and copulation. In the absence of gut bacteria, flies fed with full diets had significantly decreased mean fecundity and copulation rate. Flies that were fed with sucrose diet had a very low copulation rate and produced no eggs. Diet type and the presence of bacteria did not have any effect on the average longevity ofmale and female flies. Bacterial supplementation in sucrose diets did not improve any of the measured parameters. The results demonstrate that gut bacteria interact with diet to influence mating and reproduction in B. minax. Symbiotic bacteria significantly and positively impact reproduction in B. minax; however, their impact can only be fully realized when the flies are fed with a nutritionally complete diet

    Pyrosequencing Reveals a Shift in Symbiotic Bacteria Populations Across Life Stages of \u3cem\u3eBactrocera Dorsalis\u3c/em\u3e

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    Bactrocera dorsalis is one of the most economically important fruit flies around the world. In this study, 454 pyrosequencing was used to identify the bacteria associated with different developmental stages of B. dorsalis. At ≥ 97% nucleotide similarity, total reads could be assigned to 172 Operational Taxonomic Units belonging to six phyla. Proteobacteria dominated in immature stages while Firmicutes dominated in adult stages. The most abundant families were Enterococcaceae and Comamondaceae. The genus Comamonas was most abundant in pupae whereas completely absent in adults. Some identified species had low sequence similarity to reported species indicating the possibility of novel taxa. However, a majority sequence reads were similar to sequences previously identified to be associated with Bactrocera correcta, suggesting a characteristic microbial fauna for this insect genus. The type and abundance of different bacterial groups varied across the life stages of B. dorsalis. Selection pressure exerted by the host insect as a result of its habitat and diet choices could be the reason for the observed shift in the bacteria groups. These findings increase our understanding of the intricate symbiotic relationships between bacteria and B. dorsalis and provide clues to develop potential biocontrol techniques against this fruit fly

    The correlation between changes in gray matter microstructure and cerebral blood flow in Alzheimer’s disease

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    ObjectiveTo investigate the relationship between changes in cerebral blood flow (CBF) and gray matter (GM) microstructure in Alzheimer’s disease (AD) and mild cognitive impairment (MCI).MethodsA recruited cohort of 23 AD patients, 40 MCI patients, and 37 normal controls (NCs) underwent diffusional kurtosis imaging (DKI) for microstructure evaluation and pseudo-continuous arterial spin labeling (pCASL) for CBF assessment. We investigated the differences in diffusion- and perfusion-related parameters across the three groups, including CBF, mean diffusivity (MD), mean kurtosis (MK), and fractional anisotropy (FA). These quantitative parameters were compared using volume-based analyses for the deep GM and surface-based analyses for the cortical GM. The correlation between CBF, diffusion parameters, and cognitive scores was assessed using Spearman coefficients, respectively. The diagnostic performance of different parameters was investigated with k-nearest neighbor (KNN) analysis, using fivefold cross-validation to generate the mean accuracy (mAcc), mean precision (mPre), and mean area under the curve (mAuc).ResultsIn the cortical GM, CBF reduction primarily occurred in the parietal and temporal lobes. Microstructural abnormalities were predominantly noted in the parietal, temporal, and frontal lobes. In the deep GM, more regions showed DKI and CBF parametric changes at the MCI stage. MD showed most of the significant abnormalities among all the DKI metrics. The MD, FA, MK, and CBF values of many GM regions were significantly correlated with cognitive scores. In the whole sample, the MD, FA, and MK were associated with CBF in most evaluated regions, with lower CBF values associated with higher MD, lower FA, or lower MK values in the left occipital lobe, left frontal lobe, and right parietal lobe. CBF values performed best (mAuc = 0.876) for distinguishing the MCI from the NC group. Last, MD values performed best (mAuc = 0.939) for distinguishing the AD from the NC group.ConclusionGray matter microstructure and CBF are closely related in AD. Increased MD, decreased FA, and MK are accompanied by decreased blood perfusion throughout the AD course. Furthermore, CBF values are valuable for the predictive diagnosis of MCI and AD. GM microstructural changes are promising as novel neuroimaging biomarkers of AD

    Efficient location privacy algorithm for Internet of Things (IoT) services and applications

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    © 2016 Elsevier Ltd. Location-based Services (LBS) have become a very important area for research with the rapid development of Internet of Things (IoT) technology and the ubiquitous use of smartphones and social networks in our daily lives. Although users can enjoy a lot of flexibility and conveniences from the LBS with IoT, they may also lose their privacy. Untrusted or malicious LBS servers with all users' information can track users in various ways or release personal data to third parties. In this work, we first analyze the current dummy-location selection (DLS) algorithm-an efficient location privacy preservation approach and design an attack algorithm for DLS (ADLS) for test emerging IoT security. For efficiently preserving user's location privacy, we propose a novel dummy location privacy-preserving (DLP) algorithm by considering both computational costs and various privacy requirements of different users. Extensive simulation experiments have been carried out to evaluate the efficiency of the proposed schemes. Evaluation results show that the ADLS algorithm has a high probability of identifying the user's real location out from chosen dummy locations in the DLS algorithm. Our proposed DLP algorithm has clear advantages over the DLS algorithm in term of lower probability of revealing the user's real location and improved computational cost and efficiency (i.e., time, speed, accuracy, and complexity) while preserve the same privacy level as DLS algorithm

    Machine‑learning based prediction of prognostic risk factors in patients with invasive candidiasis infection and bacterial bloodstream infection: a singled centered retrospective study

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    Background Invasive candidal infection combined with bacterial bloodstream infection is one of the common nosocomial infections that is also the main cause of morbidity and mortality. The incidence of invasive Candidal infection with bacterial bloodstream infection is increasing year by year worldwide, but data on China is still limited. Methods We included 246 hospitalised patients who had invasive candidal infection combined with a bacterial bloodstream infection from January 2013 to January 2018; we collected and analysed the relevant epidemiological information and used machine learning methods to find prognostic factors related to death (training set and test set were randomly allocated at a ratio of 7:3). Results Of the 246 patients with invasive candidal infection complicated with a bacterial bloodstream infection, the median age was 63 years (53.25–74), of which 159 (64.6%) were male, 109 (44.3%) were elderly patients (> 65 years), 238 (96.7%) were hospitalised for more than 10 days, 168 (68.3%) were admitted to ICU during hospitalisation, and most patients had records of multiple admissions within 2 years (167/246, 67.9%). The most common blood index was hypoproteinemia (169/246, 68.7%), and the most common inducement was urinary catheter use (210/246, 85.4%). Moreover, the most frequently infected fungi and bacteria were Candida parapsilosis and Acinetobacter baumannii, respectively. The main predictors of death prognosis by machine learning method are serum creatinine level, age, length of stay, stay in ICU during hospitalisation, serum albumin level, C-Reactive protein (CRP), leukocyte count, neutrophil count, Procalcitonin (PCT), and total bilirubin level. Conclusion Our results showed that the most common candida and bacteria infections were caused by Candida parapsilosis and Acinetobacter baumannii, respectively. The main predictors of death prognosis are serum creatinine level, age, length of stay, stay in ICU during hospitalisation, serum albumin level, CRP, leukocyte count, neutrophil count, PCT and total bilirubin level

    High-performance infrared photodetectors based on InAs/InAsSb/AlAsSb superlattice for 3.5 µm cutoff wavelength spectra

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    High-performance infrared p-i-n photodetectors based on InAs/InAsSb/AlAsSb superlattices on GaSb substrate have been demonstrated at 300K. These photodetectors exhibit 50% and 100% cut-off wavelength of ∼3.2 µm and ∼3.5 µm, respectively. Under -130 mV bias voltage, the device exhibits a peak responsivity of 0.56 A/W, corresponding to a quantum efficiency (QE) of 28%. The dark current density at 0 mV and -130 mV bias voltage are 8.17 × 10−2 A/cm2 and 5.02 × 10−1 A/cm2, respectively. The device exhibits a saturated dark current shot noise limited specific detectivity (D*) of 3.43 × 109 cm·Hz1/2/W (at a peak responsivity of 2.5 µm) under -130 mV of applied bias

    Therapeutic Effects of Liposome-Enveloped Ligusticum chuanxiong Essential Oil on Hypertrophic Scars in the Rabbit Ear Model

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    Hypertrophic scarring, a common proliferative disorder of dermal fibroblasts, results from an overproduction of fibroblasts and excessive deposition of collagen. Although treatment with surgical excision or steroid hormones can modify the symptoms, numerous treatment-related complications have been described. In view of this, we investigated the therapeutic effects of essential oil (EO) from rhizomes of Ligusticum chuanxiong Hort. (Umbelliferae) on formed hypertrophic scars in a rabbit ear model. EO was prepared as a liposomal formulation (liposome-enveloped essential oil, LEO) and a rabbit ear model with hypertrophic scars was established. LEO (2.5, 5, and 10%) was applied once daily to the scars for 28 days. On postoperative day 56, the scar tissue was excised for masson's trichrome staining, detection of fibroblast apoptosis, assays of the levels of collagens I and III, and analysis of the mRNA expression of matrix metalloproteinase-1 (MMP-1), caspase-3 and -9, and transforming growth factor beta 1 (TGF-β1). In addition, the scar elevation index (SEI) was also determined. As a result, LEO treatment significantly alleviated formed hypertrophic scars on rabbit ears. The levels of TGF-β1, MMP-1, collagen I, and collagen III were evidently decreased, and caspase -3 and -9 levels and apoptosis cells were markedly increased in the scar tissue. SEI was also significantly reduced. Histological findings exhibited significant amelioration of the collagen tissue. These results suggest that LEO possesses the favorable therapeutic effects on formed hypertrophic scars in the rabbit ear model and may be an effective cure for human hypertrophic scars
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