4,709 research outputs found
Physiological responses during exposure to carbon dioxide and bioeffluents at levels typically occurring indoors
Electrophysiological assessment of auditory processing disorder in children with non-syndromic cleft lip and/or palate
Objectives Cleft lip and/or palate is a common congenital craniofacial malformation found worldwide. A frequently associated disorder is conductive hearing loss, and this disorder has been thoroughly investigated in children with non-syndromic cleft lip and/or palate (NSCL/P). However, analysis of auditory processing function is rarely reported for this population, although this issue should not be ignored since abnormal auditory cortical structures have been found in populations with cleft disorders. The present study utilized electrophysiological tests to assess the auditory status of a large group of children with NSCL/P, and investigated whether this group had less robust central auditory processing abilities compared to craniofacially normal children. Methods 146 children with NSCL/P who had normal peripheral hearing thresholds, and 60 craniofacially normal children aged from 6 to 15 years, were recruited. Electrophysiological tests, including auditory brainstem response (ABR), P1-N1-P2 complex, and P300 component recording, were conducted. Results ABR and N1 wave latencies were significantly prolonged in children with NSCL/P. An atypical developmental trend was found for long latency potentials in children with cleft compared to control group children. Children with unilateral cleft lip and palate showed a greater level of abnormal results compared with other cleft subgroups, whereas the cleft lip subgroup had the most robust responses for all tests. Conclusion Children with NSCL/P may have slower than normal neural transmission times between the peripheral auditory nerve and brainstem. Possible delayed development of myelination and synaptogenesis may also influence auditory processing function in this population. Present research outcomes were consistent with previous, smaller sample size, electrophysiological studies on infants and children with cleft lip/palate disorders. In view of the these findings, and reports of educational disadvantage associated with cleft disorders, further research that focuses on the auditory processing abilities of children with cleft lip/palate disorder is warranted.published_or_final_versio
Effect of feed rate on forming quality of cross wedge rolling of gear shaft teeth
In order to improve the forming quality of cross wedge rolling of gear shaft teeth, this paper adopts the single factor research method and uses DEFORM - 3D software to carry out the finite element simulation of the rolling process with different feed rate dies.The results show that the total feed rate of 2,75 mm is the most appropriate, and the tooth top defect of rolled piece gear can be repaired under this condition. The feed rate in the first stage is more important than that in the other stages, and the suitable range of it is 1,0 mm - 1,2 mm
Isolation of Stilbenoids and Lignans from Dendrobium hongdie
Purpose: To isolate and characterize chemical compounds of biological importance from the whole plant of Dendrobium hongdie.Methods: The whole plants of Dendrobium hongdie was extracted with ethanol (EtOH) and separated using silica gel, Sephadex LH-20 and MCI gel to isolate the pure compounds. Characterization of the isolated compounds was achieved using 1H and 13C nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS).Results: Nine compounds including two phenanthrenes, three bibenzyls, a phenanthraquinone, two lignans and a sterol were isolated from the extract. The structures of the compounds were elucidated as nudol (1), gigantol (2), batatasin III (3), tristin (4), moscatin (5), ephemeranthoquinone (6), (-)- syringaresinol (7), liriodendrin (8) and β-sitosterol (9).Conclusion: Nine compounds have been successfully isolated from D. hongdie for the first time. This plant is a potential source of some useful phytochemicals.Keywords: Dendrobium hongdie, Isolation, Stilbenoids, Lignans, Phytochemical
Finding sands in the eyes: vulnerabilities discovery in IoT with EUFuzzer on human machine interface
In supervisory control and data acquisition (SCADA) systems or the Internet of Things (IoT), human machine interface (HMI) performs the function of data acquisition and control, providing the operators with a view of the whole plant and access to monitoring and interacting with the system. The compromise of HMI will result in lost of view (LoV), which means the state of the whole system is invisible to operators. The worst case is that adversaries can manipulate control commands through HMI to damage the physical plant. HMI often relies on poorly understood proprietary protocols, which are time-sensitive, and usually keeps a persistent connection for hours even days. All these factors together make the vulnerability mining of HMI a tough job. In this paper, we present EUFuzzer, a novel fuzzing tool to assist testers in HMI vulnerability discovery. EUFuzzer first identifies packet fields of the specific protocol and classifies all fields into four types, then using a relatively high efficiency fuzzing method to test HMI. The experimental results show that EUFuzzer is capable of identifying packet fields and revealing bugs. EUFuzzer also successfully triggers flaws of actual proprietary SCADA protocol implementation on HMI, which the SCADA software vendor has confirmed that four were zero-day vulnerabilities and has taken measures to patch up
Research on temperature field and microstructure distribution of cross wedge rolling based on square billet
With the deepening and popularization of the cross wedge rolling process, the requirements for the cross wedge rolling blanks have become wider and wider. Relying only on the traditional round blanks will restrict the promotion of the cross wedge rolling process to a certain extent. The emergence of the square billet is a breakthrough in the selection of raw materials, but related research is relatively scarce. Therefore, this paper conducts a finite element simulation for the rolling process of the square billet. Four characteristic points are taken on the longitudinal section of the billet to track the temperature change. Research on the law of field changes. At the same time, the change of the grain size and dynamic recrystallization percentage of the rolled piece during the rolling process is studied. Simulation and experiment are combined to obtain the change rule of the average grain size of the characteristic points of the longitudinal section of the billet with time
Association of Exposure to Particular Matter and Carotid Intima-Media Thickness: A Systematic Review and Meta-Analysis
Background: Long time exposure to particular matter has been linked to myocardial infarction, stroke and blood pressure, but its association with atherosclerosis is not clear. This meta-analysis was aimed at assessing whether PM2.5 and PM10 have an effect on subclinical atherosclerosis measured by carotid intima-media thickness (CIMT). Methods: Pubmed, Ovid Medline, Embase and NICK between 1948 and 31 March 2015 were searched by combining the keywords about exposure to the outcome related words. The random-effects model was applied in computing the change of CIMT and their corresponding 95% confidence interval (95% CI). The effect of potential confounding factors was assessed by stratified analysis and the impact of traffic proximity was also estimated. Results: Among 56 identified studies, 11 articles satisfied the inclusion criteria. In overall analysis increments of 10 μg/m3 in PM2.5 and PM10 were associated with an increase of CIMT (16.79 μm; 95% CI, 4.95–28.63 μm and 4.13 μm; 95% CI, −5.79–14.04 μm, respectively). Results shown in subgroup analysis had reference value for comparing with those of the overall analysis. The impact of traffic proximity on CIMT was uncertain. Conclusions: Exposure to PM2.5 had a significant association with CIMT and for women the effect may be more obvious
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