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排序方式: 共有3817条查询结果,搜索用时 156 毫秒
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Da Hyeon Choi Jiwon Park Ju Kwang Choi Kyeong Eun Lee Won Hee Lee Jinho Yang Ju Yeon Lee Yoon Jeong Park Chan Oh Ho-Ryun Won Bon Seok Koo Jae Won Chang Yoon Shin Park 《Experimental & molecular medicine》2020,52(9):1564
Oral microbes have the capacity to spread throughout the gastrointestinal system and are strongly associated with multiple diseases. Given that tonsils are located between the oral cavity and the laryngopharynx at the gateway of the alimentary and respiratory tracts, tonsillar tissue may also be affected by microbiota from both the oral cavity (saliva) and the alimentary tract. Here, we analyzed the distribution and association of the microbial communities in the saliva and tonsils of Korean children subjected to tonsillectomy because of tonsil hyperplasia (n = 29). The microbiome profiles of saliva and tonsils were established via 16S rRNA gene sequencing. Based on the alpha diversity indices, the microbial communities of the two groups showed high similarities. According to Spearman’s ranking correlation analysis, the distribution of Treponema, the causative bacterium of periodontitis, in saliva and tonsils was found to have a significant positive correlation. Two representative microbes, Prevotella in saliva and Alloprevotella in tonsils, were negatively correlated, while Treponema 2 showed a strong positive correlation between saliva and tonsils. Taken together, strong similarities in the microbial communities of the tonsils and saliva are evident in terms of diversity and composition. The saliva microbiome is expected to significantly affect the tonsil microbiome. Furthermore, we suggest that our study creates an opportunity for tonsillar microbiome research to facilitate the development of novel microbiome-based therapeutic strategies.Subject terms: Comparative genomics, Metagenomics 相似文献
3.
The use of soft X-rays in a neutrahzer represents an alternative technique that could replace conventional radioactive sources.In this study,we evaluated the charging characteristics of a soft X-ray aerosol neutralize!".In addition,the results from the evaluation of the soft X-ray charger were compared with results obtained using a neutralizer incorporating an 241Am radioactive source.The tandem differential mobility analyzer technique was used previously to determine the size-dependent positive,negative,and neutral charge fractions of a soft X-ray neutralizer.This technique was used to show that the neutral fractions obtained using the soft X-ray charger agreed well with the predictions of bipolar diffusion charging theory,and that the soft X-ray charger could be used as a neutralizer for a scanning mobility particle sizer system. 相似文献
4.
Quantitative analysis of polyhexamethylene guanidine (PHMG) oligomers via matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry with an ionic‐liquid matrix 下载免费PDF全文
5.
Jin Tae Kim Keun Byoung Yoon Choon-Gi Choi 《Photonics Technology Letters, IEEE》2004,16(7):1664-1666
A novel fabrication process using a hot embossing technique has been developed for micromechanical passive alignment of polymer planar lightwave circuit (PLC) devices. With only one step of embossing, single-mode waveguide straight channels and micropedestals for passive aligning are simultaneously defined on a polymer thin film with an accuracy of /spl plusmn/0.5 /spl mu/m. This process reduces the steps for fabricating alignment structures. A fabricated polymer PLC chip and fibers are combined on a v-grooved silicon optical bench (SiOB) in a flip-chip manner. The process provides a coupling loss as low as 0.67 dB per coupling face and a cost-effective packaging solution for various polymer PLC devices. 相似文献
6.
Dong-Soo Yoon Jae Sung Roh Sung-Man Lee Hong Koo Baik 《Journal of Electronic Materials》2003,32(8):890-898
The effect of a thin RuOx layer formed on the Ru/TiN/doped poly-Si/Si stack structure was compared with that on the RuOx/TiN/doped poly-Si/Si stack structure over the post-deposition annealing temperature ranges of 450–600°C. The Ru/TiN/poly-Si/Si
contact system exhibited linear behavior at forward bias with a small increase in the total resistance up to 600°C. The RuOx/TiN/poly-Si/Si contact system exhibited nonlinear characteristics under forward bias at 450°C, which is attributed to no
formation of a thin RuOx layer at the RuOx surface and porous-amorphous microstructure. In the former case, the addition of oxygen at the surface layer of the Ru film
by pre-annealing leads to the formation of a thin RuOx layer and chemically strong Ru-O bonds. This results from the retardation of oxygen diffusion caused by the discontinuity
of diffusion paths. In particular, the RuOx layer in a nonstoichiometric state is changed to the RuO2-crystalline phase in a stoichiometric state after post-deposition annealing; this phase can act as an oxygen-capture layer.
Therefore, it appears that the electrical properties of the Ru/TiN/poly-Si/Si contact system are better than those of the
RuOx/TiN/poly-Si/Si contact system. 相似文献
7.
This paper analyzes probability of bit-error (Pe) performance of asynchronous bandlimited direct-sequence code-division multiple-access systems with binary phase-shift keying spreading. The two present methods of Pe analysis under bandwidth-efficient pulse shaping: the often-cited standard Gaussian approximation and the characteristic function (CF) method suffer from either a low accuracy in regions of low Pe (< 10-3) or a prohibitively large computational complexity. The paper presents an alternate method of Pe analysis with moderate computational complexity and high accuracy based on a key observation. A sequence of chip decision statistics (whose sum yields a bit statistic) forms a stationary, m-dependent sequence when conditioned on the chip delay and phase offset of each interfering signal. This observation permits the generalization of the improved Gaussian approximation previously derived for the rectangular pulse and the derivation of a numerically efficient approximation based on the CF method. Numerical examples of systems using the square-root raised-cosine and IS-95 pulses illustrate THE P e performance, user capacity and the accuracy of the proposed method 相似文献
8.
Jong Chan Lee Jin Young Park So Young Yoon Yong Hun Bae Seung Jun Lee 《Tetrahedron letters》2004,45(1):191-193
A novel and direct method for the synthesis of α-halocarbonyl compounds using sequential treatment of carbonyl compounds with [hydroxy(tosyloxy)iodo]benzene followed by magnesium halides under solvent-free microwave irradiation conditions is described. 相似文献
9.
Dielectric reliability in Al2O3(2–3.1nm)–HfO2(3nm) stack capacitor with Metal–Insulator–Si(MIS) structure is investigated in this paper. We propose an optimized capacitor process through the Time–Dependent Dielectric Breakdown (TDDB) data under various process conditions. Furthermore, due to asymmetric current at both negative and positive voltage stress polarities, we show different lifetime extrapolation by a fluence–driven model. As a result, the maximum allowed operating voltage is projected to be 1.7V (failure rate 10ppm during 10year @ 85°C) for Data “0” retention lifetime. 相似文献
10.
A signal registration strategy from micropatterned immunosensors that converts antigen-antibody binding reactions into electrochemical signals was demonstrated. An array-type micropatterned gold electrode on a silicon wafer was fabricated, containing two electrode geometries of rectangular (100 microm x 500 microm) and circular (r. 50 microm) types, exhibiting electrochemical characteristics of bulk and micro-electrodes, respectively. Ferritin was employed as a model analyte for immunosensing because it has an advantageous molecular structure for functionalization to the sensing interface, and is regarded as a general marker protein for tumors and cancer recurrence. With the fabricated and ferritin-functionalized immunosensors, biospecific interactions were performed with antiferritin antiserum and secondary antibody samples, followed by electrochemical signaling via an immunoprecipitation reaction by the label enzyme. Under the optimized affinity-surface construction steps and reaction conditions, both types of microfabricated electrodes exhibited well-defined calibration results as a function of the protein concentration in antiserum samples. Furthermore, circular-type micropatterned immunoelectrodes exhibited voltammetric characteristics of microelectrodes, which is advantageous in terms of sensor operation under a fixed potential and low signal drift during the signaling reaction compared with the bulk-type electrodes. The results support that the employed signaling method with the proposed immunosensor configuration is fit for sensor miniaturization and integration to future biomicrosystems. 相似文献