Nonparaxial Propagation of Rotating Cosh-Gaussian Beams

Dongmei Deng,Xi Peng,Chidao Chen,Bo Chen,Yulian Peng,Meiling Zhou 한국물리학회 2015 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.66 No.5

Starting from the inhomogeneous Helmholtz equation, we obtain the exact rotating Cosh-Gaussian vector potential solution oriented along the propagation axis (i.e., the z axis). The electricand the magnetic fields are both expressed in terms of rotating Cosh-Gaussian beams (RCGBs) thatare rigorous solutions to Maxwell’s equations. The paraxial and the nonparaxial RCGBs have aninherent rotating property in that the angular velocity decreases with increasing the propagationdistance. The evolution of the Poynting vector of the RCGBs is analyzed as they propagate in freespace.

Surface-Enhanced Raman Scattering (SERS) Active Gold Nanoparticles Decorated on a Porous Polymer Filter

Chen, Lei,Yan, Huiying,Xue, Xiangxin,Jiang, Dayu,Cai, Yuxi,Liang, Dongmei,Jung, Young Mee,Han, Xiao Xia,Zhao, Bing SAGE Publications 2017 APPLIED SPECTROSCOPY Vol.71 No.7

<P>In this work, we designed a process to assemble gold nanoparticles onto a three-dimensional (3D) polymer surface, which can then be monitored using surface-enhanced Raman scattering (SERS). This work is the first demonstration of the assembly of gold nanoparticles on a filter film and in situ measurement with Raman spectroscopy. Herein, a polyhexamethylene adipamide (Nylon66) film embedded in the organic filter film was used as a template to fabricate a tunable SERS-active substrate. A 'hotspot''-rich gold-nanoparticle-decorated polymer substrate for SERS was prepared; this substrate exhibited high sensitivity in trace detection of targets. The study was conducted using 4-mercaptobenzoic acid as a probe molecule with the aim of comparing the scattering efficiency and the homogeneity of the Raman signal on selected substrates. In addition, we used the gold-decorated polymer film to detect a biotin-avidin complex. The most powerful advantage of the proposed microanalytical device is the in situ SERS application. The 3D nanoporous structures described in this work hold strong potential for use in various applications such as environmental monitoring and biomolecule detection.</P>

Gut Microbiota Dysbiosis Correlates With Long COVID-19 at One-Year After Discharge

Zhang Dongmei,Zhou Yaya,Ma Yanling,Chen Ping,Tang Jian,Yang Bohan,Li Hui,Liang Mengyuan,Xue YuE,Liu Yao,Zhang Jianchu,Wang Xiaorong 대한의학회 2023 Journal of Korean medical science Vol.38 No.15

Background: Long coronavirus disease 2019 (COVID-19) in recovered patients (RPs) is gradually recognized by more people. However, how long it will last and the underlining mechanism remains unclear. Methods: We conducted a prospective follow-up study to evaluate the long-term symptoms and clinical indices of RPs at one-year after discharge from Union Hospital, Wuhan, China between December 2020 to May 2021. We also performed the 16S rRNA sequencing of stool samples from RPs and healthy controls (HCs) and analyzed the correlation between the gut microbiota and long COVID-19. Results: In total, 187 RPs were enrolled, among them, 84 (44.9%) RPs reported long COVID-19 symptoms at one-year after discharge. The most common long-term symptoms were cardiopulmonary symptoms, including chest tightness after activity (39/187, 20.9%), palpitations on exercise (27/187, 14.4%), sputum (21/187, 11.2%), cough (15/187, 8.0%) and chest pain (13/187, 7.0%), followed by systemic symptoms including fatigue (34/187, 18.2%) and myalgia (20/187, 10.7%), and digestive symptoms including constipation (14/187, 7.5%), anorexia (13/187, 7.0%), and diarrhea (8/187, 4.3%). Sixty-six (35.9%) RPs presented either anxiety or depression (42/187 [22.8%] and 53/187 [28.8%] respectively), and the proportion of anxiety or depression in the long symptomatic group was significantly higher than that in the asymptomatic group (41/187 [50.6%] vs. 25/187 [24.3%]). Compared with the asymptomatic group, scores of all nine 36-Item Short Form General Health Survey domains were lower in the symptomatic group (all P < 0.05). One hundred thirty RPs and 32 HCs (non-severe acute respiratory syndrome coronavirus 2 infected subjects) performed fecal sample sequencing. Compared with HCs, symptomatic RPs had obvious gut microbiota dysbiosis including significantly reduced bacterial diversities and lower relative abundance of short-chain fatty acids (SCFAs)-producing salutary symbionts such as Eubacterium_hallii_group, Subdoligranulum, Ruminococcus, Dorea, Coprococcus, and Eubacterium_ventriosum_group. Meanwhile, the relative abundance of Eubacterium_hallii_group, Subdoligranulum, and Ruminococcus showed decreasing tendencies between HCs, the asymptomatic group, and the symptomatic group. Conclusion: This study demonstrated the presence of long COVID-19 which correlates with gut microbiota dysbiosis in RPs at one-year after discharge, indicating gut microbiota may play an important role in long COVID-19.

Effect of guide vane profile on the hydraulic performance of moderate lowspecific-speed Francis turbine

Xiaoming Chen,Xide Lai,Qiuqin Gou,Dongmei Song 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.3

The matching between the guide vane (GV) and runner is essential for the stable and efficient operation of hydraulic turbines. To investigate the compatibility between GV and runner, we have conducted the numerical calculations of a moderate low-specific-speed Francis turbine at 25 operating points within the operating range of 130-190 m head and 3-19° GV outflow angle. The energy characteristics, flow field characteristics, and static pressure variation of turbines with different GV profile types have been comparatively analyzed. The results show that moderate low-specific-speed Francis turbines with symmetrical and negative curvature GV demonstrate higher efficiency under medium to high head, 55-100 % rated output operating conditions. Under small opening and medium head conditions, the static pressure in the blade leading edge is smaller, and the low-pressure area is larger for the Francis turbine with positive curvature GV. When the GV opening increases, the relationship between the comparative values of static-pressure and low-pressure areas reverses. The turbine with positive curvature GV is more favorable for increasing static-pressure and narrow low-pressure areas, which can reduce the cavitation damage. Our study provides guidelines to optimize the design of GVs and runner for hydraulic turbines.

Pharmacokinetics/Pharmacodynamics models of veterinary antimicrobial agents

Wanhe Luo,Dongmei Chen,Mengru Wu,Zhenxia Li,Yanfei Tao,Qianying Liu,Yuanhu Pan,Wei Qu,Zonghui Yuan,Shuyu Xie 대한수의학회 2019 Journal of Veterinary Science Vol.20 No.5

Misuse and abuse of veterinary antimicrobial agents have led to an alarming increase in bacterial resistance, clinical treatment failure, and drug residues. To address these problems, consistent and appropriate dosage regimens for veterinary antimicrobial agents are needed. Pharmacokinetics/Pharmacodynamics (PK/PD) models have been widely used to establish rational dosage regimens for veterinary antimicrobial agents that can achieve effective prevention and treatment of bacterial diseases and avoid the development of bacterial resistance. This review introduces building methods for PK/PD models and describes current PK/PD research progress toward rational dosage regimens for veterinary antimicrobial agents. Finally, the challenges and prospects of PK/PD models in the design of dosage regimens for veterinary antimicrobial agents are reviewed. This review will help to increase awareness of PK/PD modeling among veterinarians and hopefully promote its development and future use.

Platform Strategy and Market Response Impact on the Success of Crowdfunding: A Chinese Case

Li Guo,Dongmei Zhou,Yang Chen,Ratanak Huy 아시아기술혁신학회 2015 Asian Journal of Innovation and Policy Vol.4 No.3

Nowadays, crowdfunding presents a promising development. This research focuses on the influence of platform strategy and market response on the success of crowdfunding from the perspective of the elaboration likelihood model (ELM) theory. Detailed product specifications, crowdfunding difficulty coefficient, vivid advertising video such as introduction and music, and recommendations from relevant figures are all used to depict platform strategy. Meanwhile, we use the number of lovers, followers, comments and 1 RMB backers to measure the level of market response. And thus, we model the impact of platform strategy and market response on crowdfunding success with empirical studies based on 400 samples of observed value. We found firstly that there exist significant positive relations between the total amount of funds pledged and detailed product specification, vivid advertising video, recommendations from relevant figures and the number of 1 RMB backers. Secondly, the crowdfunding difficulty of projects affects negatively, and significantly, the total amount of funds pledged. Thirdly, the influence of the number of lovers and followers on funds pledged is not significant.

Fire Behaviors of Multilayer Latex Foam Coated by Thin Surface Fabric under Bottom Ventilation Conditions

Yiming Shen,Kai Zhang,Dongmei Huang,Chaoyi Wang,Chen Chen,De Li,Long Shi 한국고분자학회 2021 폴리머 Vol.45 No.1

The latex mattress is usually accompanied by fire risk due to its coating material and multi-layer structure. The fire behaviors of multi-layer (with a total thickness of 5 cm) latex foam coated with different fabric layer under bottom ventilation conditions were investigated experimentally. Experimental results showed that fabric coated on the surface of the multi-layer sample could significantly affect the fire behaviors. The combustion duration and peak mass loss rate of single layer sample were obtained 30% shorter and 25% larger than that of the coated samples, respectively. The effects of blending coated from the latex foam surface on the fire behaviors were found larger than those from the cotton coated sample. The total combustion duration and average fuel regression rate of cotton coated samples reduced by 34%, 43.2% when compared to those of the blending coated samples, respectively. With the increase of the number of latex foam layers, the fuel regression rate in the depth direction of the sample increases.

A Rapid and Effective Colony PCR Procedure for Screening Transformants in Several Common Mushrooms

( Yuanyuan Wang ),( Danyun Xu ),( Dongmei Liu ),( Xueyan Sun ),( Yue Chen ),( Lisheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2019 Mycobiology Vol.47 No.3

In the post-genomic era, gene function analysis has attracted much attention. Transformation is often needed to investigate gene function. In this study, an easy, rapid, reliable, and cost-effective colony polymerase chain reaction (PCR) method for screening mushroom transformants was developed: picking up a suitable amount of transformant’s tissue (1-10 lg) to 20 ll 0.25% Lywallzyme solution, and vortexing for 10 s followed by incubation at 34 ℃ for 15 min. Finally, 2 ll of the suspension was used as templates to perform PCR and single target bands were successfully amplified from respective transformants of Tremella fuciformis, Pleurotus ostreatus, and Pleurotus tuber-regium. This procedure could be widely employed for screening transformants in mushroom transformation experiments.

Evaluation of Renal Oxygenation Level Changes after Water Loading Using Susceptibility-Weighted Imaging and T2* Mapping

Jiule Ding,Wei Xing,Dongmei Wu,Jie Chen,Liang Pan,Jun Sun,Shijun Xing,Yongming Dai 대한영상의학회 2015 Korean Journal of Radiology Vol.16 No.4

To assess the feasibility of susceptibility-weighted imaging (SWI) while monitoring changes in renal oxygenation level after water loading. Thirty-two volunteers (age, 28.0 ± 2.2 years) were enrolled in this study. SWI and multi-echo gradient echo sequence-based T2* mapping were used to cover the kidney before and after water loading. Cortical and medullary parameters were measured using small regions of interest, and their relative changes due to water loading were calculated based on baseline and post-water loading data. An intraclass correlation coefficient analysis was used to assess inter-observer reliability of each parameter. A receiver operating characteristic curve analysis was conducted to compare the performance of the two methods for detecting renal oxygenation changes due to water loading. Both medullary phase and medullary T2* values increased after water loading (p < 0.001), although poor correlations were found between the phase changes and the T2* changes (p > 0.05). Interobserver reliability was excellent for the T2* values, good for SWI cortical phase values, and moderate for the SWI medullary phase values. The area under receiver operating characteristic curve of the SWI medullary phase values was 0.85 and was not different from the medullary T2* value (0.84). Susceptibility-weighted imaging enabled monitoring changes in the oxygenation level in the medulla after water loading, and may allow comparable feasibility to detect renal oxygenation level changes due to water loading compared with that of T2* mapping.

An Improved Total RNA Extraction Method for White Jelly Mushroom Tremella fuciformis Rich in Polysaccharides

( Hanyu Zhu ),( Xueyan Sun ),( Dongmei Liu ),( Liesheng Zheng ),( Liguo Chen ),( Aimin Ma ) 한국균학회 2017 Mycobiology Vol.45 No.4

An improved method for extracting high quality and quantity RNA from a jelly mushroom and a dimorphic fungus―Tremella fuciformis which is especially rich in polysaccharides, is described. RNA was extracted from T. fuciformis mycelium M1332 and its parental monokaryotic yeast-like cells Y13 and Y32. The A260/280 and A260/230 ratios were both approximately 2, and the RNA integrity number was larger than 8.9. The yields of RNA were between 108 and 213 μg/g fresh wt. Downstream molecular applications including reverse transcriptional PCR and quantitative real-time PCR were also performed. This protocol is reliable and may be widely applicable for total RNA extraction from other jelly mushrooms or filamentous fungi rich in polysaccharides.