6,107 research outputs found

    Fabrication of micro-scale radiation shielding structures using tungsten nanoink through electrohydrodynamic inkjet printing

    Get PDF
    Electronics components used in space and strategic missions are exposed to harsh radiation environments, which could cause operational malfunction of the system through lattice displacement or ionization effects. One potential solution is to use tungsten as radiation shielding. Tungsten is a very effective material in shielding electronic components and manufacturing gratings for x-ray imaging. However, intrinsic properties of tungsten (e.g. density, chemical/thermal inertness and hardness) post a significant challenge of fabricating the material into micro-scale and delicate structures, especially in electronic device fabrication. To address the problem, we designed a new tungsten nanoink and developed a straightforward approach to create tungsten micro-structures by 3D printing. Various microstructures down to 10 µm resolution have been patterned and fabricated by electrohydrodynamic inkjet (e-jet) printing using tungsten nanoink. By optimizing process parameters (voltage modality) and materials properties (ink formulation), the dimension and morphology of the structures can be precisely controlled. An AC-modulated voltage was employed during the e-jet printing process to make the patterns much more controllable and stable. Multi-layer tungsten lines were characterized by x-ray imaging and exhibited excellent absorption of x-ray radiation. With the same thickness, printed lines showed nearly 1/3 absorptivity of x-ray radiation of bulk tungsten, leading to significant radiation attenuation effectiveness. Tungsten nanoink is a new material used in e-jet printing that has not been reported in the literature to the best of authors\u27 knowledge. The study establishes a new methodology of manufacturing micro-nano scale shielding components for electronic devices and rapid prototyping of gratings and collimators in radiography for medical and inspection applications. The research also provides practical guidance to fabricate high melting-point metals via nanoink and micro/nano scale 3D printing

    New Optimal Weight Combination Model for Forecasting Precipitation

    Get PDF
    In order to overcome the inaccuracy of the forecast of a single model, a new optimal weight combination model is established to increase accuracies in precipitation forecasting, in which three forecast submodels based on rank set pair analysis (R-SPA) model, radical basis function (RBF) model and autoregressive model (AR) and one weight optimization model based on improved real-code genetic algorithm (IRGA) are introduced. The new model for forecasting precipitation time series is tested using the annual precipitation data of Beijing, China, from 1978 to 2008. Results indicate the optimal weights were obtained by using genetic algorithm in the new optimal weight combination model. Compared with the results of R-SPA, RBF, and AR models, the new model can improve the forecast accuracy of precipitation in terms of the error sum of squares. The amount of improved precision is 22.6%, 47.4%, 40.6%, respectively. This new forecast method is an extension to the combination prediction method

    Clinical analysis of vitrectomy in treatment of 48 eyes with metallic foreign bodies

    Get PDF
    AIM: To investigate the effect of vitrectomy in treatment of metal intraocular foreign bodies and the factors affecting visual prognosis.<p>METHODS:Fourty seven cases(48 eyes)with foreign bodies from January 2010 to June 2013 in our hospital underwent vitrectomy combined with intraocular foreign body removal were retrospectively analyzed. The changes of visual acuity, the size of foreign body, the complications of preoperative, and the relationship between treatment time and visual acuity were recorded. <p>RESULTS: Totally 46 eyes were successfully removed the complete foreign body, 2 eyes of orbital foreign bodies had not been removed. After 6mo of followed-up, the best corrected visual acuity were all improved in varying degrees(<i>P</i><0.05), intraocular foreign body size combined with retinal detachment was the risk factor for visual impact(<i>P</i><0.05).<p>CONCLUSION:Vitrectomy has obvious advantages in the treatment of metal intraocular foreign bodies. Timely and appropriate vitrectomy is very important to the recovery of visual function

    Changes of oxidant-antioxidant parameters in small intestines from rabbits infected with E. intestinalis and E. magna

    Full text link
    [EN] Rabbit coccidiosis is a very serious disease caused by protozoan parasites of the genus Eimeria, which increases the production rate of free radicals, especially reactive oxygen species. When the generation of free radicals exceeds the scavenging capacity of the body s antioxidant system, the oxidant-antioxidant balance is broken, resulting in oxidative stress. This study was designed to investigate the effect on the oxidant-antioxidant status of rabbits infected with E. intestinalis and E. magna. To this end, eighteen 30-d-old weaned rabbits were randomly allocated into three groups as follows: the E. intestinalis infection group with 3×103 sporulated oocysts of E. intestinalis, the E. magna infection group with 20×103 sporulated oocysts of E. magna, and the uninfected control group. We measured the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) and the contents of malondialdehyde (MDA) in rabbits small intestinal tissues (duodenum, jejunum and ileum) of the three groupson day 8. The results showed that CAT activity and MDA levels significantly increased, while the activities of SOD, GSH-Px and T-AOC decreased after E. intestinalis and E. magna infection. Besides, the jejunum and ileum were particularly damaged in the rabbits. It is concluded that the pathological oxidative stress occurs during the E. intestinalis and E. magna infection process and the body s oxidant-antioxidant balance is disrupted.This experiment was supported by the National Natural Science Foundation Project of China (nos. 31960688 and 31360592) and the Natural Science Foundation Project of Jiangxi Province (no. 20181BAB204016).Zhou, YX.; Yuan, X.; Hu, XF.; Yang, SS.; Zhong, SW.; Yang, TY.; Zhao, GT.... (2022). Changes of oxidant-antioxidant parameters in small intestines from rabbits infected with E. intestinalis and E. magna. World Rabbit Science. 30(4):287-293. https://doi.org/10.4995/wrs.2022.1739528729330

    Incorporating productivity loss in health economic evaluations : a review of guidelines and practices worldwide for research agenda in China

    Get PDF
    Introduction: Productivity loss may contribute to a large proportion of costs of health conditions in an economic evaluation from a societal perspective, but there is currently a lack of methodological consensus on how productivity loss should be measured and valued. Despite the research progress surrounding this issue in other countries, it has been rarely discussed in China. Methods: We reviewed the official guidelines on economic evaluations in different countries and regions and screened the literature to summarise the extent to which productivity loss was incorporated in economic evaluations and the underlying methodological challenges. Results: A total of 48 guidelines from 46 countries/regions were included. Although 32 (67%) guidelines recommend excluding productivity loss in the base case analysis, 23 (48%) guidelines recommend including productivity loss in the base case or additional analyses. Through a review of systematic reviews and the economic evaluation studies included in these reviews, we found that the average probability of incorporating productivity loss in an economic evaluation was 10.2%. Among the economic evaluations (n=478) that explicitly considered productivity loss, most (n=455) considered losses from paid work, while only a few studies (n=23) considered unpaid work losses. Recognising the existing methodological challenges and the specific context of China, we proposed a practical research agenda and a disease list for progress on this topic, including the development of the disease list comprehensively consisting of health conditions where the productivity loss should be incorporated into economic evaluations. Conclusion: An increasing number of guidelines recommend the inclusion of productivity loss in the base case or additional analyses of economic evaluation. We optimistically expect that more Chinese researchers notice the importance of incorporating productivity loss in economic evaluations and anticipate guidelines that may be suitable for Chinese practitioners and decision-makers that facilitate the advancement of research on productivity loss measurement and valuation

    Functional specialization and interaction in the amygdala-hippocampus circuit during working memory processing

    Full text link
    Both the hippocampus and amygdala are involved in working memory (WM) processing. However, their specific role in WM is still an open question. Here, we simultaneously recorded intracranial EEG from the amygdala and hippocampus of epilepsy patients while performing a WM task, and compared their representation patterns during the encoding and maintenance periods. By combining multivariate representational analysis and connectivity analyses with machine learning methods, our results revealed a functional specialization of the amygdala-hippocampal circuit: The mnemonic representations in the amygdala were highly distinct and decreased from encoding to maintenance. The hippocampal representations, however, were more similar across different items but remained stable in the absence of the stimulus. WM encoding and maintenance were associated with bidirectional information flow between the amygdala and the hippocampus in low-frequency bands (1-40 Hz). Furthermore, the decoding accuracy on WM load was higher by using representational features in the amygdala during encoding and in the hippocampus during maintenance, and by using information flow from the amygdala during encoding and that from the hippocampus during maintenance, respectively. Taken together, our study reveals that WM processing is associated with functional specialization and interaction within the amygdala-hippocampus circuit
    corecore