Elimination Problem Research Articles

Palladium(0) versus Nickel(0) Catalysis in Selective Functional‐Group‐Tolerant sp3–sp3 Carbon–Carbon Bond Formations

We have uncovered Pd(0)-catalyzed intermolecular nonsymmetrical Suzuki-Miyaura-type sp(3)-sp(3) C-C bond formations between allyl carbonates and nontoxic allyl, allenyl, or propargyl boronates. This report represents the first use of these types of boronic esters in this particular context. The present transformations proceeded with high selectivity under remarkably mild conditions, and various functional groups including an aldehyde function proved to be compatible. In addition, several boronates were found to display very unusual reactivity patterns; the higher reactivity of boron as apposed to silicon was clearly demonstrated as well. Finally, the inherent problem of beta-hydride elimination associated with intermediary allyl-Pd species was addressed by employing a commercially available Ni(0) catalyst.

Integration of PEGylation and refolding for renaturation of recombinant proteins from insoluble aggregates produced in bacteria—Application to a single-chain Fv fragment

The conjugation of polyethylene glycol (PEGylation) with downsized compact antibodies is an effective method for overcoming the problem of rapid elimination of the compact antibodies from the body. We integrated site-specific PEGylation with the refolding of a single-chain Fv (scFv) of humanized monoclonal antibody 528 with affinity for the epidermal growth factor receptor, to prepare active PEGylated scFv from insoluble aggregates produced in an Escherichia coli expression system. The insertion of a cysteine residue at the C-terminus of scFv to serve as the conjugation site for PEG led to the formation of highly multimeric scFv during the refolding process; however, PEGylation after refolding drastically dispersed the multimer into monomeric active scFv fragments. Further, the PEGylation of partially refolded scFv during the refolding process improved the PEGylation efficiency and suppressed the formation of highly multimeric scFv; consequently, monomeric active scFv fragments were obtained directly from the insoluble aggregates in E. coli. We show that in vitro refolding of PEGylated scFv should be useful for improving downstream processing performance in the production of clinically useful small antibodies from insoluble fractions.

Pulse width modulation AC/DC converters with line current harmonics minimisation and high power factor using hybrid particle swarm optimisation

A hybrid optimisation method based on the combination of the particle swarm optimisation (PSO) method and the Newton's method is proposed for optimised control of a voltage source three-phase three-level AC/DC converter. Three control objectives are considered: minimising the total harmonic current distortion (THD), maintaining high power factor (PF) and keeping the DC-link voltage at a reference value. The switching time of the pulse width modulation (PWM) AC/DC converter is determined by using the proposed method. It is observed that PSO has more possibilities to explore a large space and therefore offers a near optimal solution and the Newton's method is used to fine tune the solution obtained by PSO. The proposed method is also applied to selective harmonic elimination (SHE) problem. Simulation results verify that harmonic distortion obtained by the proposed control scheme is lower than that of SHE techniques and natural sampling PWM (NS-PWM) method. Experimental results are presented to demonstrate the validity and efficiency of optimised control strategy.

Potential risk factors associated with feline behaviour problems

A retrospective study was carried out on feline behaviour problems presented at the Animal Behaviour Clinic at the Barcelona School of Veterinary Medicine to identify the main risk factors. Three hundred thirty six cats presented for a behaviour problem between 1998 and 2006 were included in the study group. A total of 189 presented at the Hospital of the Barcelona School of Veterinary Medicine for problems other than behavioural and having no record of behaviour problems were used as control group. The main owner's complaint was aggression (47%) followed by inappropriate elimination (39%). 64% of aggression cases involved conflicts between cats and 36% of cases were aggression towards people, owners being the most common target of aggression (78% of all cases of aggression were directed towards people). Play-related aggression and petting-related aggression were the main causes of aggressive behaviour towards people (43.1 and 39.6% of cases respectively). Most housesoiling problems involved urination (59%), followed by urination and defecation (32%) and defecation (9%), and the most common diagnosis was aversion to the litterbox (63.4%). Persian cats were presented more frequently for elimination problems than other breeds ( χ 2 = 6.40; p < 0.01). Cats with behaviour problems came from pet shops more frequently than control cats ( χ 2 = 10.39; p < 0.001). Cats without outdoor access showed significantly more behaviour problems than those with outdoor access ( χ 2 = 31.85; p < 0.001) and aggression problems were more common in single cat households than in multicat households ( χ 2 = 25.47; p < 0.001). Intact females were presented more frequently for aggression problems than neutered females ( χ 2 = 7.74; p < 0.01).

Differences between subtotal corpectomy and laminoplasty for cervical spondylotic myelopathy

This study aimed to obtain guidelines for choosing between subtotal corpectomy (SC) and laminoplasty (LP) by analysing the surgical outcomes, radiological changes and problems associated with each surgical modality. A retrospective analysis of two interventional case series. Department of Orthopaedic Surgery, Kagawa University, Japan. Subjects comprised 34 patients who underwent SC and 49 patients who underwent LP. SC was performed by high-speed drilling to remove vertebral bodies. Autologous strut bone grafting was used. LP was performed as an expansive open-door LP. The level of decompression was from C3 to C7. Clinical evaluations included recovery rate (RR), frequency of C5 root palsy after surgery, re-operation and axial pain. Radiographic assessments included sagittal cervical alignment and bone union. Comparisons between the two groups showed no significant differences in age at surgery, preoperative factors, RR and frequency of C5 palsy. Progression of kyphotic changes, operation time and volumes of blood loss and blood transfusion were significantly greater in the SC (two- or three-level) group. Six patients in the SC group required additional surgery because of pseudoarthrosis, and four patients underwent re-operation because of adjacent level disc degeneration. In the LP group, the problem of elimination of postoperative axial symptoms remains to be solved. The merit of SC is the low frequency of axial symptoms. One-level SC can be considered to have similar degree of invasiveness as LP. Compared with SC, LP is more suitable for elderly patients with multilevel stenosis.

Predicting Falls Among Psychiatric Inpatients: A Case-Control Study at a State Psychiatric Facility

Predicting Falls Among Psychiatric Inpatients: A Case-Control Study at a State Psychiatric Facility

Educational needs of patients with multiple sclerosis (MS)

Background With respect to different problems and complications of patients with multiple sclerosis (MS), appropriate educational programs and interventions should be performed for them to promote their quality of life. Purpose This descriptive study was conducted to identify educational needs of patients who were the members of Iranian MS Society in 2007. Methods 174 subjects referring to the society were selected with convenience sampling method. A questionnaire in 4 parts was used for data collection. Results Most subjects (26.4%) were between 32-39, women (71%) as well as married (59.8%) and history of the disease less than 3 years (27.7%). 39.1% was in great need of education, 0.6% of disease nature, 94% of sexual disorders and 64.8% of administrative problems. A significant relationship was found between educational needs concerning physical issues and education (P=0.027) and also these needs and times of hospitalization (P=0.004). Conclusion It can be concluded that the most urgent educational needs were about sexual problems, mobility problems and administrative problems and the lowest need for education was about elimination problems. Keywords: Educational needs, Multiple sclerosis, Iranian Multiple Sclerosis Society. Physical needs.

Exploring the effect of Hesperetin-HSPC complex--a novel drug delivery system on the in vitro release, therapeutic efficacy and pharmacokinetics.

Hesperetin is known to exhibit a variety of pharmacological activities in mammalian cell systems. Although it shows appreciable bioavailability when administered orally, its faster elimination from body creates the need of frequent administration to maintain effective plasma concentration. To overcome this limitation, a phospholipid complex of hesperetin was prepared and evaluated for antioxidant activity and pharmacokinetic profile. The hesperetin content of the complex was determined by a spectrophotometer and the surface characteristics of the complex were studied by means of microscope. The antioxidant activity was evaluated in carbon-tetrachloride-intoxicated rats at a dose level of 100 mg/kg body weight, p.o. The complex was studied for in vitro drug release characteristics and effect of complexation on serum concentration of hesperetin in rats was also studied along with main pharmacokinetic parameters. The results showed that the complex has a sustained release property and enhanced antioxidant activity (P < 0.05 and <0.01) as compared to free hesperetin at the same dose level. Pharmacokinetic study depicted that the complex has higher relative bioavailability and acted for a longer period of time. The study therefore suggests that phospholipid complex of hesperetin produced better antioxidant activity than free drug at the same dose level and the effect persisted for a longer period of time, which may be helpful in solving the problems of faster elimination of the molecule.

A Generalized Formulation of Quarter-Wave Symmetry SHE-PWM Problems for Multilevel Inverters

A generalized formulation of quarter-wave symmetrical selective harmonic elimination (SHE) problems according to the rising and falling edges of the pulsewidth modulation (PWM) waveforms for multilevel inverters is proposed. The SHE modulation scheme features a broad solution space and can eliminate a large number of low-order harmonics. An effective method for obtaining initial values of switching angles is proposed. This method is based on rules of equal area and superposition of center of gravity (cg) of the PWM section with the sine reference signal. To illustrate the effectiveness of the proposed SHE method, a five-level voltage source inverter with elimination of 11 low-order harmonics is investigated. The SHE-PWM equations that can eliminate harmonics from 5th to 35th with modulation index <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">M</i> varying from 0 to 1.15 are formulated, and solutions are presented. Simulations and experiments based on two sets of solutions are carried out. It is demonstrated that the experimental results agree well with simulated ones, which proves the validity and practicability of the new method proposed.

An application of PSO technique for harmonic elimination in a PWM inverter

Harmonic elimination problem in PWM inverter is treated as an optimization problem and solved using particle swarm optimization (PSO) technique. The derived equation for computation of total harmonic distortion (THD) of the output voltage of PWM inverter is used as the objective function in the PSO algorithm. The objective function is minimized to contribute the minimum THD in the voltage waveform and the corresponding switching angles are computed. The method is applied to investigate the switching patterns of both unipolar and bipolar case. While minimizing the objective function, the individual selected harmonics like 5th, 7th, 11th and 13th can be controlled within the allowable limits by incorporating the constraints in the PSO algorithm. The results of the unipolar case using five switching angles are compared with that of a recently reported work and it is observed that the proposed method is effective in reducing the voltage THD in a wide range of modulation index. The simulated results are also validated through suitable experiments.

Investigating Algebraic and Logical Algorithms to Solve Hopf Bifurcation Problems in Algebraic Biology

Symbolic methods to investigate Hopf bifurcation problems of vector fields arising in the context of algebraic biology have recently obtained renewed attention. However, the symbolic investigations have not been fully algorithmic but required a sequence of symbolic computations intervened with ad hoc insights and decisions made by a human. In this paper we discuss the use of algebraic and logical methods to reduce questions on the existence of Hopf bifurcations in parameterized polynomial vector fields to quantifier elimination problems over the reals combined with the use of the quantifier elimination over the reals and simplification techniques available in REDLOG. We can reconstruct most of the results given in the literature within a few seconds of computation time and extend the investigations on these systems to previously not analyzed related systems. Especially we discuss cases in which one suspects that no Hopf bifurcation fixed point exists for biologically relevant values of parameters and system variables. Here we focus on logical and algebraic techniques of finding subconditions being inconsistent with the hypothesis of the existence of Hopf bifurcation fixed points.

Matrix Cubes Parameterized by Eigenvalues

An elimination problem in semidefinite programming is solved by means of tensor algebra. It concerns families of matrix cube problems whose constraints are the minimum and maximum eigenvalue functions on an affine space of symmetric matrices. A linear matrix inequality (LMI) representation is given for the convex set of all feasible instances, and its boundary is studied from the perspective of algebraic geometry. This generalizes the known LMI representations of k-ellipses and k-ellipsoids.

Assessment about the measles elimination from cases and outbreaks, 2002-2007 - Assessment about the measles elimination -

Purpose : We assessed about the measles elimination in Korea according to analyzing national data on measles cases for 2002-2007. Methods : We estimated the effective reproduction number according to the proportion of imported cases and outbreak size. Results : Eleven cases, thirteen cases, six cases, six cases, 25 cases (60.0% were linked to 1 outbreak of 15 cases), and 180 cases (55.6% were linked 11 outbreaks of 2, 2, 2, 3, 3, 3, 5, 9, 9, 12, 50 cases) were reported in 2002, 2003, 2004, 2005, 2006 and 2007, respectively. In 2002-2007, R is 0.95 by imported case and 0.43 by outbreak sizes. In 2007, multiple chains of transmission occurred in hospital. Most of cases were below 4 ages and unvaccinated. We didn't find most of the infection source. Conclusion : We should prevent outbreak of susceptibility pocket like nosocomial infection, conduct reliable routine surveillance and epidemiological investigation to solve a problem of the measles elimination.

Solutions to the harmonic elimination problem in a seven level inverter

Multilevel inverters have recently emerged as very important alternatives in high power applications. Several modulation methods have been applied to multilevel inverters. When utilised at low switching frequencies, existing multilevel carrier-based pulse width modulation (PWM) strategies have no special provisions to render quality output; several lower order harmonics are included in the spectrum. The problem of eliminating selected harmonics in a chosen multilevel inverter is considered in this paper. Given a desired fundamental output voltage, the problem is to find the switching times (angles) that produce the fundamental while not generating specifically chosen harmonics. This paper proposes techniques using simulated annealing (SA), genetic algorithm (GA) and Newton-Raphson method for calculating offline the optimum switching angles of chosen seven-level inverter to eliminate the 5th and 7th harmonics. Solution through SA technique is found to be better. The switching angles provided by the three methods are implemented in a field programmable gate array (FPGA) based firing module for the chosen inverter. The simulation and hardware results are presented and evaluated. They validate the solution developed for the chosen problem.

Finding the Exact Integrality Gap for Small Traveling Salesman Problems

The symmetric traveling salesman problem (STSP) is to find a minimum weight Hamiltonian cycle in a weighted complete graph on n nodes. One direction which seems promising for finding improved solutions for the STSP is the study of a linear relaxation of this problem called the subtour elimination problem (SEP). A well-known conjecture in combinatorial optimization says that the integrality gap of the SEP is 4/3 in the metric case. Finding the exact value for this integrality gap is challenging even for small values of n as it is difficult to model this problem in a way that can be solved practically. We describe how we are able to overcome such difficulties and obtain the exact integrality gap for all values of n up to 10 and a lower bound for this gap for all values of n from 11 to 14. Our results give rise to a new stronger form of the conjecture which is dependent on n.

A multi‐agent framework to build integer programming applications to playoff elimination in sports tournaments

AbstractThis work describes a multi‐agent framework for developing autonomous applications of integer programming to playoff qualification and elimination problems in sports tournaments. These applications involve collecting results from several sources, processing them, and publishing a report on the situation of each team taking part in the competition, regarding qualification and elimination statistics. An instance of this framework was created to follow the Brazilian national football tournament, showing very good results in practice in terms of ease of use; speed of update, processing and publication; and attractiveness to the users.

Cobordism of singular maps

Throughout this paper we consider smooth maps of positive codimensions, having only stable singularities (see Arnold, Guseĭn-Zade and Varchenko [Monographs in Math. 83, Birkhauser, Boston (1988)]. We prove a conjecture, due to M Kazarian, connecting two classifying spaces in singularity theory for this type of singular maps. These spaces are: 1) Kazarian’s space (generalising Vassiliev’s algebraic complex and) showing which cohomology classes are represented by singularity strata. 2) The space Xτ giving homotopy representation of cobordisms of singular maps with a given list of allowed singularities as in work of Rimanyi and the author [Topology 37 (1998) 1177–1191; Mat. Sb. (N.S.) 108 (150) (1979) 433–456, 478; Lecture Notes in Math. 788, Springer, Berlin (1980) 223–244]. We obtain that the ranks of cobordism groups of singular maps with a given list of allowed stable singularities, and also their p–torsion parts for big primes p coincide with those of the homology groups of the corresponding Kazarian space. (A prime p is “big” if it is greater than half of the dimension of the source manifold.) For all types of Morin maps (ie when the list of allowed singularities contains only corank 1 maps) we compute these ranks explicitly. We give a very transparent homotopical description of the classifying space Xτ as a fibration. Using this fibration we solve the problem of elimination of singularities by cobordisms. (This is a modification of a question posed by Arnold [Itogi Nauki i Tekniki, Moscow (1988) 5–257].)

Elimination problems in logic: a brief history

A common aim of elimination problems for languages of logic is to express the entire content of a set of formulas of the language, or a certain part of it, in a way that is more elementary or more informative. We want to bring out that as the languages for logic grew in expressive power and, at the same time, our knowledge of their expressive limitations also grew, elimination problems in logic underwent some change. For languages other than that for monadic second-order logic, there remain important open problems.

Perfect Elimination of Regulation Transients in Discrete-Time LPV Systems via Internally Stabilizable Robust Controlled Invariant Subspaces

This note introduces a geometric solution to the problem of perfect elimination of regulation transients in discrete-time, linear systems subject to swift and wide, a priori-known, parameter variations. The constructive proof of the conditions for problem solvability requires a preliminary, strictly geometric interpretation of the multivariable autonomous regulator problem, specifically aimed at discrete-time, linear systems. The novel concept of internal stabilizability of a robust controlled invariant subspace plays a key role in the formulation of those conditions as well as in the synthesis of the control scheme.

Scalable Synthesis and Clustering Techniques Using Decision Diagrams

Binary-decision diagrams (BDDs) have proven to be an efficient means to represent and manipulate Boolean formulas and sets due to their compactness and canonicity. In this paper, we leverage the efficiency of BDDs for new areas in field-programmable gate-array (FPGA) computer-aided design (CAD) flow including cut generation and clustering by reducing these problems to BDDs and solving them using Boolean operations. As a result, we show that this leads to more than 10 reduction in runtime and memory use when compared to previous techniques, as reported by Mishchenko and Lin. This speedup allows us to apply this paper to new areas in the FPGA CAD flow previously not possible. Specifically, we introduce a new method to solve the logic-synthesis elimination problem found in FBDD, a reported BDD synthesis engine with an order-of-magnitude speedup over SIS. Our new elimination algorithm results in an overall speedup of 6 in FBDD with no impact on circuit area.