Location Management in Mobile Ad Hoc Wireless Networks Using Quorums and Clusters

Position-based reactive routing is a scalable solution for routing in mobile ad hoc networks. The route discovery algorithm in position-based routing can be efficiently implemented only if the source knows the current address of the destination. In this paper, a quorum-based location management scheme is proposed. Location servers are selected using the minimum dominating set (MDS) approach, and are further organized into quorums for location update and location query. when a mobile node moves, it updates its location servers in the update quorum; when a node requests the location information of another node, it will send a query message to the location servers in the query quorum. We propose to use the position-based quorum system, which is easy to construct and guarantees that the update quorums always intersect with the query quorums so that at least one location server in the query quorum is aware of the most recent location of the mobile node. Clusters are introduced for large scale ad hoc networks for scalability. Experiment results show that the proposed scheme provides good scalability when network size increases

Spektromikroskopische Einblicke in die Nanostruktur und Grenzflächen organischer Feldeffekttransistoren und Solarzellen

Organic electronics, e.g., organic field-effect transistors (OFETs), organic solar cells (OSCs) and organic light-emitting diodes (OLEDs), have attracted strong interest in both academia and industry during the last decades due to their unique capabilities offered by organic semiconductors. The micro-/nano-structures in active layers and the interface engineering in organic electronics are extremely important for desired device functionalities. In this thesis, the structure-function relationships and interface engineering in both OFETs and OSCs are investigated exploring standard and emerging characterization techniques with specific emphasis on soft X-ray-based methods. Firstly, OFETs based on small molecules are investigated as prototype systems to understand the micro-/nano-structure formation and its relation to charge transport properties. Specifically, the in-situ/in-operando electronic structure detection using soft X-rays is explored. Secondly, the morphology of more complex bulk heterojunction organic solar cells based on both binary and ternary components are investigated to further understand the charge generation, recombination and transport. In both cases, advanced chemically sensitive characterization methods based on soft X-rays and electrons are explored. Finally, the interface losses in all-solution processed multi-junction organic solar cells based on representative interfacial layers and active layers are discussed. A simple, yet effective and universal approach is developed to overcome the interface losses. In the first part of the discussion (Chapter 5), studies on several small molecule systems conventionally used in OFETs are presented. Firstly, co-existence of polymorphs of pentacene in sub-micron scale was investigated using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy and scanning transmission X-ray microscopy (STXM). Secondly, the thin film morphology and charge transport properties of one of the important pentacene derivatives, 6,13-dihydro-6,13-diazapentacene (DHDAP), are investigated. The performance of OFETs based on DHDAP is found to be extremely sensitive to the nature and temperature of the substrates during film preparation. We employ several complementary microscopic and spectroscopic probes to investigate the structure of thermally evaporated thin and thick films evaporated at different device-related conditions. The electronic structure of DHDAP is explored by photoelectron spectroscopy (XPS) and NEXAFS spectroscopy. Atomic force microscopy (AFM) and angle-resolved NEXAFS spectroscopy reveal the growth mode and the orientation of the molecules close to the substrates. STXM and resonant soft X-ray scattering (RSoXS) reveal the crystalline domain size distribution of the thicker films. Finally, the inter-grain boundaries density, the molecular packing and the passivation of interface traps are analyzed and correlated to the transport properties. PDI-FCN2-based n-type OFETs with Si3N4 as dielectric layer are demonstrated. The electronic structure and the temperature-dependent morphology are investigated by STXM. Furthermore, a capacitor-like device is employed for in-situ NEXAFS measurements to investigate the field-effect on the electronic structures of PDI-FCN2. The applied voltage induces changes in the NEXAFS absorption intensity, but does not result in any detectable spectral shifts. For in-operando XPS studies within the active channel of pentacene-based thin-film OFETs, significant charging of the active layer and spectral shifts according to the applied gate-voltage are observed. Thus, probing the variation of the chemical states or binding energies of the molecules within the active channel during device operation remains challenging. The next section of this thesis (Chapter 6) deals with the complex interplay of the morphology and functionality in ternary organic solar cells. A systematic study has been conducted by means of energy-filtered transmission electron microscopy (EFTEM) and RSoXS on the morphology evolution of prototype ternary systems upon adding sensitizers, namely poly(3-hexylthiophene) (P3HT) and indene-C60-bisadduct (ICBA) blends with Si-PCPDTBT and C-PCPDTBT. The model sensitizers have very similar chemical structures but significantly different influences on the nanomorphology of the ternary blends and the solar cell device performance. For deeper understanding, a combined density functional theory (DFT) and artificial neuronal network (ANN) computational approach is utilized to calculate the solubility parameters and Flory-Huggins intermolecular parameters to evaluate the influence of miscibility on the final morphology. Experiments reveal that the domain spacing and purity of ICBA-rich domains are retained in Si-PCPDTBT-based systems, but is strongly reduced in C-PCPDTBT-based ternary systems. The P3HT fiber structure is conserved at low sensitizer contents but significantly reduced at high contents. The theoretical calculations reveal very similar miscibility/compatibility between the two sensitizers and ICBA as well as P3HT. Thus, it is concluded that mainly the crystallization of Si-PCPDTBT drives the nanostructure evolution in the ternary systems, while this driving force is absent in C-PCPDTBT-based ternary blends. Moreover, the photovoltaic performance of ternary systems based on a new wide band-gap polymer is investigated and rationalized based on the above mentioned guidelines of morphology aspects. In the last part (Chapter 7), a systematic study of interface losses in both single-junction and multi-junction solar cells based on representative polymer donors and hole transporting layers (HTLs) using electron spectroscopy are reported. It is found that a facile mixed HTL (m-HTL) containing poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and molybdenum oxide (MoOx) nanoparticles successfully overcomes the interfacial losses in both single- and multi-junction solar cells based on various active layers by reducing interface protonation, promoting better energy-level alignment, and forming a dense and smooth layer. Solution-processed single-junction solar cells are demonstrated to reach the same performance as with evaporated MoOx (˃ 7%). Multi-junction solar cells with polymers containing nitrogen atoms as the first layer and mixed PEDOT:PSS and MoOx nanoparticles as HTL reach a fill factor (FF) of over 60%, and a power conversion efficiency (PCE) of over 8%, while the corresponding stack with pristine PEDOT:PSS or MoOx nanoparticles showed FF smaller than 50% and PCE less than 5%

Frost Heave Deformation Analysis Model for Microheave Filler

With the rapid development of high-speed railway, high-speed railways pose new requirements on subgrade frost heave deformation control. Microheave in conventional non-frost-heave filler cannot meet the requirements of high-speed railways for high levels of smoothness and stability and threaten high-speed train operation safety. To solve problems of seasonal permafrost region subgrade filler microheave in China, combined laboratory test and theoretical analysis, this research analyzed the physical properties of frost heave influencing factors for microheave filler. The influence of skeleton grain during frost heave formation is revealed. The microheave filler frost heave development mechanism is investigated. On this basis, based on the principle of minimum energy, a frost heave calculation formula for microheave filler is deduced, and a frost heave deformation analysis model for microheave filler is created. In addition, the effectiveness of the model is demonstrated in an indoor test. This study provides a theoretical reference for controlling the frost heaving deformation of railway subgrade

Differential effects on natural killer cell production by membrane‐bound cytokine stimulations

Please click Additional Files below to see the full abstract

Tricin protects rats from ovariectomized-induced osteoporosis by enhancing Wnt/β-catenin pathway

Purpose: To investigate the effects of tricin on ovariectomized-induced osteoporosis, and unravel theunderling mechanism of action.Methods: An osteoporosis rat model was established by conducting ovariectomy (OVX). Changes in the microstructure of the trabecular bone were visualized using Hematoxylin and eosin (H&E) staining, and a three-point bending test was employed to assess the biomechanical stability of the femurs, after the administration of tricin (20 and 40 mg/kg). Subsequently, bone marrow mesenchymal stem cells (BMSCs) were isolated and treated with tricin (7 and 15 μM). Alizarin red staining was performed to assess mineralization, and Runt-related transcription factor 2 (RUNX2); osteocalcin (OCN) and collagen type I alpha 1 (Col1a1) were quantified using western blot analysis. The Wnt/β-catenin pathway related proteins, i.e., Wnt3a, β-catenin, glycogen synthase kinase-3 β (GSK-3 β) were determined.Results: Ovariectomy induced thinner and discontinuous trabecular bone, with increased marrow cavities, while application of tricin significantly improved the density and regularity meshwork, but reduced marrow cavities. Tricin also enhanced biomechanical competence as seen in the upregulated maximum load, stiffness, young modulus and maximum stress compared with OVX group (p < 0.01). Furthermore, tricin increased calcification in BMSCs, and significantly upregulated the expressions of RUNX2, OCN and COL1A1 when compared with OVX group (p < 0.01). It promoted Wnt/β-catenin signaling by enhancing Wnt3a and β-catenin, while inhibiting GSK3β expression, compared with OVX group (p < 0.05 or p < 0.01).Conclusion: Tricin exerts protective effects against OVX-induced osteoporosis by enhancing Wnt/β-catenin pathway. Thus, tricin is a potential therapeutic agent for the management of osteoporosis

Ecological Balance of Oral Microbiota is Required to Maintain Oral Mesenchymal Stem Cell Homeostasis

Oral microbiome is essential for maintenance of oral cavity health. Imbalanced oral microbiome causes periodontal and other diseases. It is unknown whether oral microbiome affect oral stem cells function. In this study, we used a common clinical anti-biotic treatment approach to alter oral microbiome ecology and examine whether oral mesenchymal stem cells (MSCs) are affected. We found that altered oral microbiome resulted gingival MSCs deficiency, leading to a delayed wound healing in male mice. Mechanistically, oral microbiome release LPS that stimulates the expression of microRNA-21 (miR-21) and then impair the normal function of gingival MSCs and wound healing process through miR-21/Sp1/TERT pathway. This is the first study indicate that interplay between oral microbiome and MSCs homeostasis in male mice

The Fas/Fap-1/Cav-1 Complex Regulates IL-1RA Secretion in Mesenchymal Stem Cells to Accelerate Wound Healing

Mesenchymal stem cells (MSCs) are capable of secreting exosomes, extracellular vesicles, and cytokines to regulate cell and tissue homeostasis. However, it is unknown whether MSCs use a specific exocytotic fusion mechanism to secrete exosomes and cytokines. We show that Fas binds with Fas-associated phosphatase–1 (Fap-1) and caveolin-1 (Cav-1) to activate a common soluble N-ethylmaleimide–sensitive factor (NSF) attachment protein receptor (SNARE)–mediated membrane fusion mechanism to release small extracellular vesicles (sEVs) in MSCs. Moreover, we reveal that MSCs produce and secrete interleukin-1 receptor antagonist (IL-1RA) associated with sEVs to maintain rapid wound healing in the gingiva via the Fas/Fap-1/Cav-1 cascade. Tumor necrosis factor–α (TNF-α) serves as an activator to up-regulate Fas and Fap-1 expression via the nuclear factor κB pathway to promote IL-1RA release. This study identifies a previously unknown Fas/Fap-1/Cav-1 axis that regulates SNARE-mediated sEV and IL-1RA secretion in stem cells, which contributes to accelerated wound healing

Research on Design of Program - Controlled Switches

In the 1990s, the development of program-controlled switches in our country has experienced the development process from thescratch; especially the successful development of large-scale program-controlled switches has brought great vitality to our informationindustry. This time, I mainly introduced to ZTE ZXJ10 program-controlled switchboard to design distributed modularization in programcontrolledswitch. ZXJ10 digital program-controlled switching system is distributed between modules, module classification control,centralized management of the open architecture, based on general computer platform, LAN technology as the support, client/server modeto control the basic form of structure, in order to make the system has flexible networking ability, strong call processing capability, highreliability, good compatibility and expansibility