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Shunhang Feng,1,2,* Jiansheng Lin,1,2,* Xiaoyan Zhang,1,2 Xin Hong,1,2 Wanyin Xu,1,2 Yancheng Wen,1,2 Feifei She1,2 1Key Laboratory of Gastrointestinal Cancer (Fujian Medical University), Ministry of Education, Fuzhou, People’s Republic of China; 2Fujian Key Laboratory of Tumor Microbiology, Department of Medical Microbiology, School for Basic Medical Sciences, Fujian Medical University, Fuzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Feifei She, Fujian Medical University, Xueyuan Road 1, Minhou County, Fuzhou, Fujian Province, People’s Republic of China, Tel +86-135-1406-3583, Email Shefeifei@yeah.net Yancheng Wen, Fujian Medical University, Xueyuan Road 1, Minhou County, Fuzhou, Fujian Province, People’s Republic of China, Tel +86-157-0593-5209, Email hitwyc@qq.comPurpose: Helicobacter pylori is associated with the development of gastrointestinal diseases. However, its eradication is challenged by an increased rate of drug resistance. AlgC and GalU are important for the synthesis of UDP-glucose, which is a substrate for the synthesis of lipopolysaccharide (LPS) in H. pylori. In this study, we investigated the role of UDP-glucose in the intrinsic drug resistance in H. pylori.Methods: Gene knockout strains or complementation strains, including ΔalgC, ΔgalU, ΔgalE, Δhp0045, ΔalgC/algC* and ΔgalU/galU* were constructed in Hp26695; and ΔalgC and ΔgalU were also constructed in two clinical drug-resistant strains, Hp008 and Hp135. The minimum inhibitory concentrations (MIC) of H. pylori to amoxicillin (AMO), tetracycline (TET), clarithromycin (CLA), metronidazole (MNZ), levofloxacin (LEV), and rifampicin (RIF) were measured using MIC Test Strips. Silver staining was performed to examine the role of AlgC and GalU in LPS synthesis. Ethidium bromide (EB) accumulation assay was performed to assess the outer membrane permeability of H. pylori strains.Results: Knockout of algC and galU in H. pylori resulted in increased drug sensitivity to AMO, MNZ, CLA, LEV, and RIF; whereas knockout of hp0045 and galE, which are involved in GDP-fucose and UDP-galactose synthesis, respectively, did not significantly alter the drug sensitivity of H. pylori. Knockout of algC and galU in clinically drug-resistant strains resulted in significantly increased drug sensitivity to all the antibiotics, except MNZ. The lipid A-core structure was altered in ΔalgC and ΔgalU when their EB accumulation was higher than that in the wild type and complementation strains.Conclusion: UDP-glucose may play an important role in increasing drug resistance to AMO, MNZ, CLA, LEV, TET, and RIF by maintaining the lipid A-core structure and decreasing membrane permeability. AlgC and GalU may serve as potential drug targets for decreasing antibiotic resistance in clinical isolates.Keywords: H. pylori, UDP-glucose, algC, galU, intrinsic multidrug resistance

Due to the explosive growth of short text on various social media platforms, short text stream clustering has become an increasingly prominent issue. Unlike traditional text streams, short text stream data present the following characteristics: short length, weak signal, high volume, high velocity, topic drift, etc. Existing methods cannot simultaneously address two major problems very well: inferring the number of topics and topic drift. Therefore, we propose a dynamic clustering algorithm for short text streams based on the Dirichlet process (DCSS), which can automatically learn the number of topics in documents and solve the topic drift problem of short text streams. To solve the sparsity problem of short texts, DCSS considers the correlation of the topic distribution at neighbouring time points and uses the inferred topic distribution of past documents as a prior of the topic distribution at the current moment while simultaneously allowing newly streamed documents to change the posterior distribution of topics. We conduct experiments on two widely used datasets, and the results show that DCSS outperforms existing methods and has better stability.

Depending on the scanning mode, existing short text stream clustering methods can be divided into the following two kinds of methods: one-pass-based and batch-based. The one-pass-based method handles each text only one time, but cannot deal with the sparseness problem very well. The batch-based method obtains better results by allowing multiple iterations of each batch, but the efficiency is relatively low. To overcome these problems, this paper presents Lifelong learning Augmented Short Text stream clustering method (LAST), which incorporates the episodic memory module and sparse experience replay module of lifelong learning into the clustering process. Specifically, LAST processes each text one time, but at a certain interval it randomly samples some previously seen texts of the episodic memory to update cluster features by performing sparse experience replay. Empirical studies on two public datasets demonstrate that the performance of the LAST-based method is on a par with the batch-based method, and runs close to the speed of the one-pass-based method.

Objectives The local structures and mechanical properties within tooth dentin-enamel-junction (DEJ) regions have been focused for numerous studies. The reported results, however, remain inconsistent particularly on the functional width and gradient architecture of the DEJ. The current study aims at systematically determining the mechanical gradient of the DEJ at different intratooth locations such that a clearer understanding on the tooth properties and the potential correlations with the tooth function could be obtained. Methods We re-examined how mechanical properties such as elastic modulus and hardness transitioned from those of dentin to those of enamel using combined static and dynamic nanoindentation mapping techniques. A new mapping method and associated image processing procedures were developed to improve the measurement accuracy and resolution. Results A thin, sigmoidally-transitioned interphase layer of the DEJ was identified with an accurate functional width of 2–3 μm. The DEJ width and gradient architecture were found intratooth location-dependent, with the DEJ at the occlusal sites being wider and transitioning smoother than that at the cervical sites. Such different widths and architectures of the interphase layer at sites subjected to different types and magnitudes of loadings during mastication could promote more efficient stress transferring between enamel and dentin without compromising the overall stiffness of the tooth. Significance The presented study not only adds our understanding in the local mechanical properties within tooth DEJ regions, it could also further advance the development of DEJ-mimetic, functional gradient interphase for strong and ultra-durable jointing between dissimilar materials.

In sodium ion batteries, heteroatom doping is deemed to be an important way to enhance the electrochemical activity of carbon-based anode materials. In this work, we report 3D nitrogen and sulfur equilibrium co-doping hollow carbon nanosheets for sodium ion battery anode, which can deliver a maximum capacity of 497 mA h g−1 under 0.2 A g−1, good rate capability (260 mA h g−1 under 50 A g−1 and 245 mA h g−1 under 60 A g−1), and good cycling stability (339 mA h g−1 under 5 A g−1 over 5000 cycling and 249 mA h g−1 under 10 A g−1 over 5000 cycling), suggesting wonderful electrochemical performance. To the best of our knowledge, the excellent performance of the long-term cyclability at such high rates is rarely reported for carbon-based sodium ion battery anodes. Meanwhile, the storage mechanism of sodium was studied by in-situ Raman spectroscopy, cyclic/linear sweep voltammetry and electrochemical impedance spectroscopy. Its superior properties can be attributed to the special three-dimensional hollow nanosheets with high specific surface, doping regulation of N and S elements to carbon structure and synergistic effect of nitrogen doping enhancing pseudocapacitive contributions.

It is still a great challenge to develop high performance anode materials for sodium ion battery (SIB) with high rate and long cycle. In this work, we try to use one step polyvinyl alcohol (PVA)-induced method to prepare three dimensional (3D) carbon coated In2S3 nanowires assembled graphene composites as high performance SIB anode. PVA can successfully regulate and control the In2S3 structure from nanoparticles, nanosheets to nanowires. Under the adsorption of oxygen-containing functional groups of graphene skeleton, the presence of PVA backbone can also induce the 1D anisotropic growth of In2S3 nanowires. Meanwhile, the PVA layer also becomes a uniform carbon layer after carbonization and is coated on the outer surface of In2S3 nanowires. The as-prepared 3D carbon coated In2S3 nanowires assembled graphene composite electrode displays superior sodium storage performance, which can show a high reversible capacity of 509 mAh g−1 and maintain the super stable reversible capacities of 360, 256 and 165 mAh g−1 at 0.5, 2 and 6 A g−1 for 1000 cycles, respectively, which can be attributed to the 3D porous graphene composite structure, homogeneous carbon coated on In2S3 nanowire surface and S doped in carbon structure edge sites enhancing pseudocapacitive contributions.

By using the fixed point index theory, we investigate the existence of at least two positive solutions for p-Laplace equation with sign-changing nonlinear terms ('p(u 0 )) 0 +a(t)f(t,u(t),u 0 (t)) = 0, subject to some boundary conditions. As an application, we also give an example to illustrate our results.