Improved Nyquist filter characteristics using spline interpolation

This paper presents and investigates a novel approach for constructing a family of intersymbol interference (ISI)-free pulses that shows comparable or better ISI performance in the presence of sampling errors, compared with some recently proposed pulses. We propose and discuss a new parametric method for the design of Nyquist filter characteristics using constraints in frequency characteristics construction. The method for constructing the filter characteristics uses a piecewise polynomial approximation of an ideal optimized staircase characteristic by spline functions. The spline polynomials are used to approximate a function that must pass through specified points. The performances of new ISI-free pulses are studied with respect to the ISI error probability. This family provides flexibility in designing an appropriate pulse even after the roll-off factor has been chosen. The results for error probability outperform the fourth-degree polynomial pulse [4].     

Automatic brachytherapy seed placement under MRI guidance

The paper presents a robotic method of performing low dose rate prostate brachytherapy under magnetic resonance imaging (MRI) guidance. The design and operation of a fully automated MR compatible seed injector is presented. This is used with the MrBot robot for transperineal percutaneous prostate access. A new image-registration marker and algorithms are also presented. The system is integrated and tested with a 3T MRI scanner. Tests compare three different registration methods, assess the precision of performing automated seed deployment, and use the seeds to assess the accuracy of needle targeting under image guidance. Under the ideal conditions of the in vitro experiments, results show outstanding image-guided needle and seed placement accuracy.     

PLOD2 Is a Prognostic Marker in Glioblastoma That Modulates the Immune Microenvironment and Tumor Progression

This study aimed to investigate the role of Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase 2 (PLOD2) in glioblastoma (GBM) pathophysiology. To this end, PLOD2 protein expression was assessed by immunohistochemistry in two independent cohorts of patients with primary GBM (n₁ = 204 and n₂ = 203, respectively). Association with the outcome was tested by Kaplan–Meier, log-rank and multivariate Cox regression analysis in patients with confirmed IDH wild-type status. The biological effects and downstream mechanisms of PLOD2 were assessed in stable PLOD2 knock-down GBM cell lines. High levels of PLOD2 significantly associated with (p₁ = 0.020; p₂ < 0.001; log-rank) and predicted (cohort 1: HR = 1.401, CI [95%] = 1.009–1.946, p₁ = 0.044; cohort 2: HR = 1.493; CI [95%] = 1.042–2.140, p₂ = 0.029; Cox regression) the poor overall survival of GBM patients. PLOD2 knock-down inhibited tumor proliferation, invasion and anchorage-independent growth. MT1-MMP, CD44, CD99, Catenin D1 and MMP2 were downstream of PLOD2 in GBM cells. GBM cells produced soluble factors via PLOD2, which subsequently induced neutrophils to acquire a pro-tumor phenotype characterized by prolonged survival and the release of MMP9. Importantly, GBM patients with synchronous high levels of PLOD2 and neutrophil infiltration had significantly worse overall survival (p < 0.001; log-rank) compared to the other groups of GBM patients. These findings indicate that PLOD2 promotes GBM progression and might be a useful therapeutic target in this type of cancer.     

Doubly coupled systems of elliptic hemivariational inequalities: Existence and location

We develop an approach based on the subsolution–supersolution method for an elliptic system of hemivariational inequalities. The system exhibits full dependence on the gradient of the solution and is doubly coupled on both the source and multivalued terms. We prove the existence of solutions in a prescribed trapping region and, as an application, provide a criterion for obtaining positive solutions.     

Computationally designed monomers for molecular imprinting of chemical warfare agents - Part V

The main objective of this research is to develop and apply state-of-the-art computational tools to achieve an understanding of intermolecular interactions in molecular imprinting of chemical warfare (CW) agents into complex monomeric systems. Molecular dynamic (MD) simulations were carried out for different monomeric molecular systems in order to predict the interaction energies, the closest approach distances and the active site groups between the simulated molecular systems and different CW agents. The minimized structures of CW agents have been obtained with the use of molecular mechanics approach. NVT MD simulations at room temperature were carried out to obtain equilibrated conformations in all cases. The simulated molecular systems consisted of a ligand (CW agents) and commonly used functional monomers.During this study, it was found that electrostatic interactions play the most significant role in the formation of molecular imprinting materials. The simulated systems indicate that the functional groups of monomers interacting with ligands tend to be either -COOH or CH₂CH-.     

Enhanced Bio-Electrochemical Reduction of Carbon Dioxide by Using Neutral Red as a Redox Mediator

Microbial electrosynthetic cells containing Methylobacterium extorquens were studied for the reduction of CO₂ to formate by direct electron injection and redox mediator-assisted approaches, with CO₂ as the sole carbon source. The formation of a biofilm on a carbon felt (CF) electrode was achieved while applying a constant potential of −0.75 V versus Ag/AgCl under CO₂-saturated conditions. During the biofilm growth period, continuous H₂ evolution was observed. The long-term performance for CO₂ reduction of the biofilm with and without neutral red as a redox mediator was studied by an applied potential of −0.75 V versus Ag/AgCl. The neutral red was introduced into the systems in two different ways: homogeneous (dissolved in solution) and heterogeneous (electropolymerized onto the working electrode). The heterogeneous approach was investigated in the microbial system, for the first time, where the CF working electrode was coated with poly(neutral red) by the oxidative electropolymerization thereof. The formation of poly(neutral red) was characterized by spectroscopic techniques. During long-term electrolysis up to 17 weeks, the formation of formate was observed continuously with an average Faradaic efficiency of 4 %. With the contribution of neutral red, higher formate accumulation was observed. Moreover, the microbial electrosynthetic cell was characterized by means of electrochemical impedance spectroscopy to obtain more information on the CO₂ reduction mechanism.     

Heterogeneous cationic polymerization of 1,3-dioxolane and 1,3-dioxepane using grafted BF3 on silica

Summary A BF₃ complex has been grafted onto silica and used as initiator to polymerize 1,3-dioxolane and 1,3-dioxepane. Grafting the active centers leads to a decrease of the reaction rate. The molecular weight increases steadily, parallel to the monomer conversion and the polydispersity is rapidly stabilized at a low value. MALDI-TOF mass spectrometry analysis shows that most of the polymer chains are initiated by a proton and lost a CH₂O unit. An exchange process between polymer chains bound to the silica and those remaining in the reactional medium was proposed. Finally, a semi-continuous process was investigated by adding continuously dioxolane during a 100 hours period. Received: 21 February 2001/ Revised version: 2 November 2001/ Accepted: 6 November 2001     

Catalytic Combustion of the Stoichiometric n-Butane/Air Mixture on Isothermally Heated Platinum Wire

The catalytic combustion of the stoichiometric n-butane–air mixture per se or diluted with N₂, on a platinum wire at different initial pressures (10–70 kPa) and temperatures (690–1,080 K) was studied. The chemical heat flow rate, dQ _r/dt, of the surface reaction was measured in isothermal and isobaric conditions and the overall kinetic parameters were evaluated for both steady state and initial transient catalytic combustion. At low total pressure (10 kPa), the temperature dependence of dQ _r/dt indicated a normal (Arrhenius) behavior for 690 < T < 900 K, while at higher temperatures, over 900 K, an anti-Arrhenius behavior was found. The obtained results are consistent with a diffusion-controlled process, accompanied by reactant depletion around the catalytic surface, at higher temperatures.     

新型锥差式液压马达的运动与效率分析

本文分析了新型锥差式液压马达的运动与效率.     

Poly(4-vinylpyridine)-based hydrogen bonded side-chain liquid crystal polymers

Novel liquid crystalline (LC) poly(4-vinylpyridine) (PVP)-based side-chain polymers were prepared from PVP and cyanobiphenyl (HOCnB) derivatives through intermolecular hydrogen-bonding between hydroxyl groups of the cyanobiphenyl derivatives and the nitrogen of PVP. PVP was used as a hydrogen bond acceptor polymer. A series of HOCnB having a linear alkoxy chain HOCnH_2n + 1O–(n = 2–6) have been used as H-bond donor. The existence of H-bonding was confirmed using FTIR spectroscopy. The polymeric complexes behave as LC polymers and exhibit stable mesophases. DSC and optical microscopy were used to investigate LC behaviour. All PVP–LC-complexes exhibited stable and homogeneous nematic phases. On increasing spacer length or concentration of the hydrogen bonded mesogenic unit in the complex, the clearing temperature and the temperature range of the nematic phase increased. The binary phase diagram of the polymeric complexes PVP–HOCnB showed complete miscibility over the entire range of composition. Molecular interactions of self-assembled SCLCP presented the idea that various LC-complexes could be prepared through mixing a functionalised polymer with various low molar mass mesogens.