bluuebunny/crossref_metadata_2025_split huggingface dataset:
Topological conditions for the solvability of linear active networks
Authors: Ozawa Takao 
Published: June 2007

AbstractThe solvability problem of a linear active network is approached from a purely topological point of view using the two‐graph method. It can be said that a topological condition for the solvability is the existence of a common tree of the voltage and current graphs. A few conditions for the existence of a common tree are derived. If there exists no common tree, subgraphs which cause the nonexistence can be distinguished, and a partition of two‐graphs can be introduced. The partition has similar properties to the principal partition of a graph or the canonical form of a bipartite graph, and a structure of two‐graphs represented by a partial ordering of sets of edges can be defined. An algorithm to find the partition and a common tree, if one exists, or if no common tree exists, a tree of one of the graphs which has as many common edges as possible with a tree of the other graph, is given. The decomposition of the coefficient matrix accompanying the structure is discussed, and algorithms to determine the decomposition is given.
Stable high q active networks
Authors: Levi A. , Zeheb E. 
Published: June 2007

AbstractA new approach is suggested to approximate the amplitude frequency behaviour of a given high Q poles network function, by an explicit function having poles with a predetermined desired low Q, and with explicit knowledge and control of the error. The method is practical for reducing Q's by the ratio of up to 6. Any critical pole‐pair is replaced by an approximating function possessing a complex conjugate n‐th order pole‐pair and a (n−1)‐th order zero‐pair. A general second order low Q building block is derived as an example. Measured results proving the practical usefulness of the method, are reported.
Algorithms for the element values in a class of stub‐unit‐element cascades
Authors: McLaughlin L. , Rhodes J. D. 
Published: June 2007

AbstractAttempting to unify the various papers in the literature revolving around the classical ideas of moment theory, this paper by considering various generalizations of the orthogonal polynomial concept, examines the microwave equivalent of the lumped ladder structure.The stub‐unit‐element cascades that result are shown to be synthesizable in terms of the properties of Hurwitz generalized orthogonal polynomials. Using this concept, the synthesis procedure leads to element value algorithms, both for the reactance ladder case, and the case where the unit‐elements become redundant (in the sense that they do not contribute to synthesis).As an example, explicit element value formulas are derived for lowpass and bandpass reflection filters using stub‐unit element‐cascades, that exhibit maximally flat delay and amplitude characteristics.Lastly, using the concept of a complex weight function, the relationship between the approximation of a transfer impedance and the synthesis of the resulting structure, is considered.The considerations discussed here appear to have many possible lines for extension: to multivariable networks; alternative one‐variable structures; and to the question of the existence of explicit element value formulas for particular filters.
On the minimal realization of the gyrator by means of nullors and resistors. II
Authors: Deprettere E. 
Published: June 2007

AbstractIt is proved that it is impossible to synthesize a gyrator with only two nullors and three resistors. Combining the results obtained in References 1 and 2 and in this paper, we obtain the following necessary and sufficient conditions: a nullor‐resistor gyrator realization is minimal if and only if it consists of either two nullors and four resistors or three nullors and two resistors.
Maximally flat non‐recursive digital filters
Authors: Fahmy M. F. 
Published: June 2007

AbstractA new class of polynomials with derivative constraints at both x= ± 1, is introduced. Such polynomials can be used in the design of non‐recursive digital filters with maximally flat amplitude response at both ±T= 0 and ±T= 180 degrees, as well as the design of certain class of microwave networks. As compared with the already known methods1, the proposed design method provides some advantages.
A lumped‐distributed small‐signal model for a class of transit‐time semiconductor devices
Authors: Quang Nguyen 
Published: June 2007

AbstractIn this paper a new lumped‐distributed small‐signal and noise model is presented for a class of transit‐time semiconductor devices including the IMPATT, BARITT, Transferred Electron and Space Charge Limited (SCL) diodes. The assumption of uniform carrier velocity is made and diffusion is neglected. The diode‐model is composed of lumped elements and dispersionless transmission lines, hence it is very suitable for computer‐aided circuit analysis. Broad agreement has been found between the experimental behaviour of devices and that of their models.
Generalized linear phase polynomials—application in filter synthesis
Authors: Jarry P. , Garault Y. , Clapeau M. 
Published: June 2007

AbstractIn this paper, we give explicit expressions for the study of attenuation and phase characteristics of generalized linear phase polynomials (i.e. Jacobi and generalized Bessel polynomials for transmission line and lumped filters respectively). We present an exact method to find the digital transfer function which exhibits [n/2] to (n−1) simultaneous conditions on amplitude and delay.
Graph‐theoretic state models for the piecewise analysis of large‐scale electrical networks
Authors: Chandrashekar M. , Kesavan H. K. 
Published: June 2007

AbstractState models based on graph‐theoretical concepts are presented for the computer‐aided analysis of large‐scale linear networks by decomposition in time as well as frequency domains. Several examples are analysed which illustrate the validity and efficiency of these models. These models exploit the sparsity and the repetitive structure present in most large‐scale networks.
On the application of degree theory to the analysis of resistive nonlinear networks
Authors: Chua Leon O. , Wang Niantsu N. 
Published: June 2007

AbstractThis paper presents an application of the theory of the degree of a map to the study of the existence of solutions and some related problems for resistive nonlinear networks. Many well‐known results in this area have been generalized to allow coupling among the nonlinear resistors. The usual hypothesis requiring the nonlinear resistors to be eventually increasing has been weakened considerably by only requiring the resistors to be eventually passive. Instead of investigating special cases by special techniques, we study the network equations from a geometrical point of view. The concept of homotopy of odd fields provides a unified yet simple approach for analyzing a large class of practical nonlinear networks. Many known results belong to this category and are derived as special cases of our generalized theorems. This approach leads to a much better understanding of the geometric structure of the vector fields associated with the network equations. As a result, in so far as the existence of solutions is concerned, the concept of eventual passivity is shown to be far more basic than that of eventual increasingness. The emphasis of the concept of eventual passivity also leads naturally to the inclusion of coupling among the nonlinear resistors.The homotopy of odd fields also provides some useful techniques for locating the solutions. Along this line, we also study the bounding region of solutions and discuss the operating range of nonlinear resistors.
Modulated carriers in nonlinear systems
Authors: Van Nie A. G. 
Published: June 2007

AbstractThe systems to be considered consist of linear and nonlinear elements and are driven by a priori known periodic signals (carriers). The present theory deals with small perturbations from the periodic steady state. Use has been made of the ‘amplitude‐phase’ representation of the perturbations. The operator (jω0 + λ) is used, in which jω0 indicates the time differentiation of the carrier components and the operator λ ( = d/dt) affects the perturbation only. The perturbations will be related by a ‘sensitivity’ matrix H. In order to illustrate the applicability of this theory, the performance of the dynamic limiter of Zaalberg van Zelst will be treated.
A successive filtering technique for identifying long‐term trends
Authors: Assimakopoulos V. 
Published: July 2007

AbstractThe most reliable component of a time series, for forecasting purposes, is the shape of the long‐term trend. However, the presence of cycles makes it difficult to identify and predict the changes in such trends. While up to now emphasis has been given in identifying and measuring cyclical behaviour, this paper presents a technique that aims at removing cyclical effects from the long‐term trends. This technique is based on a transformation that is successively applied on the original time series. Each time the transformation is applied, an observation is selected and replaced by the average of its adjacent observations. This results in the elimination of the cyclical component. Independently of their depth, the cycles are being removed in ascending order relatively to their length. This leads to 'brushing off' the long‐term trends from any cyclical effects. A specialized software has been developed in Pascal. The proposed technique was applied in a set of time series from the M2‐ and M‐competition and the results are presented in this paper.
Lower leg replantation—Decision‐making, treatment, and long‐term results
Authors: Hierner Robert , Berger Alfred Karl , Frederix Peter Reynders 
Published: June 2007

AbstractObject: The aim of this article is to review the results of replantation at the lower leg after total and subtotal amputation injury. Although subtotal and total lower leg amputations have been successfully replanted in the past, nowadays there is a common opinion that these operations do not justify their efforts, and therefore most of those patients are amputated. Methods: To clarify this hypothesis we carried out an extensive literature research. The following criteria were evaluated: 1) survival rate, 2) individual motor and sensory functions and global lower extremity function judged according to the classification of Chen, 3) socioeconomic aspects (operation time, number of operations per patient, time of hospitalization, and return to normal life), and 4) number and nature of local and/or systemic complications. Results: The success rate of lower leg amputation, which only means perfect resortation of viability, is reported between 62.5% and 100%. Using Chen's classification the functional results can be given as follows: A “functional extremity” (grade I and grade II) can be reconstructed in 82.6% to 92.7%. A non‐functional extremity (grade III and grade IV) will result in one tenth to one fifth of cases. Complications can be classified in local or systemic and occur depending on the quality of the decision‐making process. Conclusion: Our results as well as those of other large series show that lower leg replantation is still worthwhile in a well selected patient group, contrary to what is believed by an increasing number of orthopaedic and trauma surgeons. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
The free deltoid flap: Clinical applications to upper extremity, lower extremity, and maxillary defects
Authors: Meltem Ayhan , Metin Gorgu , Zeynep Aytug , Cenk Melikoglu , Betul Ulusal Gozel 
Published: June 2007

AbstractThe deltoid free flap is a thin, reliable flap that is easily dissected from the posterolateral arm. It has large‐caliber vessels and is capable of sensory reinnervation to portions of the flap above the deltoid/triceps groove through the lateral brachial cutaneous nerve. There is little sensory return to the large vascular territory, which can be extended inferiorly below the deltoid triceps groove. The donor site can be closed primarily or skin grafted and when large may be objectionable to some patients. The flap is an excellent choice for extremity soft‐tissue reconstruction on the plantar or palmar surfaces. Because of its excellent color‐matching and texture‐matching characteristics, it has recently been widely used for the reconstruction of soft‐tissue defects during oral and maxillofacial surgery. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
Signals in pathological CNS extracts of ALS mice promote hMSCs neurogenic differentiation in vitro
Authors: Zhao Cui‐Ping , Zhang Cheng , Wang Yi‐Hua , Zhou Sheng‐Nian , Zhou Chang , Li Wan‐Yi , Yu Mei‐Juan 
Published: June 2007

AbstractThe capability of MSCs to differentiate into neurons has been proven by many studies. Recently, other studies have cast doubt on MSCs neurogenic differentiation with non‐physiological chemical inducing agents in vitro. This present study was designed to use conditioned medium to investigate whether signals from pathological condition of ALS were competent to induce a program of neurogenic differentiation in expanded cultures of hMSCs. Incubation of hMSCs with conditioned medium prepared from CNS extracts of ALS mice (SOD1‐G93A ALS mice) resulted in a time‐dependent morphological change from fibroblast‐like into neuron‐like, concomitant with increase in the expression of Nestin and subsequent β‐tubulin III, NSE and GAP43. Moreover, signals in pathological CNS extracts of ALS mice were more effective in promoting hMSCs neurogenic differentiation than those in physiological extracts of normal adult mice. These results show that pathological condition of ALS is endowed with capacity to induce hMSCs neurogenic differentiation and hMSCs have shown a potential candidate in cellular therapy for ALS.
Protective role of carnitine in breast cancer via decreasing arginase activity and increasing nitric oxide
Authors: Erbas Hakan , Aydogdu Nurettin , Usta Ufuk , Erten Oya 
Published: June 2007

AbstractBreast cancer remains one of the most common types of cancer. High levels of arginase and ornithine in different carcinomas may indicate their relation to cancer. Carnitine is a cofactor required for the transformation of free long‐chain fatty acids into acetyl‐carnitines. We have examined the protective effect of carnitine and the possibility that it disturbs arginase—nitric oxide (NO) interaction. Histopathological examination, arginase activity, ornithine and NO levels were determined in tumour tissues. Mitotic cells significantly decreased in the treatment group. Tissue arginase activity and ornithine levels decreased significantly with carnitine. NO levels were significantly higher in the treatment group. One of the possible mechanisms of carnitine's protective role in tumour progression might be its promotion of NO. This mechanism could decrease the production of tumour‐promoting agents, polyamines, and increase the production of NO, thereby exerting a protective effect on cancer development.
Interleukin‐10 inhibits the down‐regulation of ATP binding cassette transporter A1 by tumour necrosis factor‐alpha in THP‐1 macrophage‐derived foam cells
Authors: Mei Chun‐li , Chen Zhi‐jian , Liao Yu‐hua , Wang Yan‐fu , Peng Hong‐yu , Chen Yu 
Published: June 2007

AbstractIt is suggested that cholesterol efflux mediated by ATP binding cassette transporter A1 (ABCA1) plays an important role in anti‐atherogenesis. However, the effects of inflammatory cytokines on ABCA1 expression and cholesterol accumulation in foam cells are little known. This study investigates the effects of tumour necrosis factor‐alpha (TNF‐α) and interleukin‐10 (IL‐10) on ABCA1 expression and cholesterol content in THP‐1 macrophage‐derived foam cells. ABCA1mRNA and protein levels were determined by RT‐PCR and Western blot, respectively. The total cholesterol content in THP‐1 macrophage‐derived foam cells was detected by the zymochemistry method. Results revealed that TNF‐α could increase cholesterol content by down‐regulating ABCA1 expression in a time‐dependent manner in THP‐1 macrophage‐derived foam cells, which may contribute to its pro‐atherosclerotic effect. In addition IL‐10 time‐dependently decreased cholesterol accumulation by up‐regulating ABCA1 expression and inhibited the down‐regulation of ABCA1 by TNF‐α in THP‐1 macrophage‐derived foam cells, which may be one of the mechanisms of IL‐10 contributing to its anti‐atherosclerotic action.
Patient Perception and Assessment of Admission to Acute Cardiac Care Unit
Authors: Nakano Anne , Mainz Jan , Lomborg Kirsten 
Published: June 2007

Background: To provide equal care and treatment of cardiac patients it is common practice to base the work on clinical guidelines. These guidelines mainly cover the provider perspective rather than the patient perspective. Patient satisfaction, however, is an important parameter within quality development of professional services in hospitals. Patient satisfaction is, i.e. connected with the amount of information provided to the patient and how much patients are involved in their care and treatment. This is also assumed to apply within cardiac practice. However, in relation to acute admission there is no clear picture of the patients' real preferences; likewise there is no documentation whether these preferences correspond with the nurses' assumptions. Aim: The aim of this study was primarily to investigate what preoccupied patients admitted to cardiac care units with acute coronary syndrome in connection with the first hours of their admission, and secondly to discuss these perceptions in relation to the nurses' perception from a previous pilot study. Method: A qualitative descriptive analysis of 30 semi-structured interviews was carried out to investigate the patient perception and assessment of care and treatment by acute admission. Results: The patients included 22 men and 8 women with an average age of 59 (SD = 11.5) years. In all, 5 themes: efficiency, professionalism, pain management, compassionate nursing and information were considered essential and all together they expressed what preoccupied the patients. Conclusion: It is possible to show what the patients think is important, also during acute admission. In general, the patients felt they were in good hands. Most important was the care providers' competencies and that they “knew their job”. The patients' experience of pain management might suggest insufficient care and treatment within this field.
Physicochemical modeling as applied to study of sulfoarsenide complexes in hydrothermal solutions
Authors: Vilor N.V. , Kaz’min L.A. 
Published: June 2007

Abstract
System As–Na–S–Cl–H–O was studied. The research was carried out in three stages: (1) selection of the most likely complexes resulting from arsenic sulfide dissolution, (2) calculation of their thermodynamic constants, and (3) comparison of calculated data with thermodynamic database obtained in tests with the solution of inverse thermodynamic problems using the Selektor program complex. The system As–Na–S–Cl–H–O included more than 230 dependent components, which were divided into two groups, base and functional. The former group includes components of the solution (NaCl, NaOH, Na2S, NaHS, HCl, H2S, H2SO4, sulfates, H2SO3, sulfites, thiosulfates, Na+, Cl−,HS−, S2−), gas phase (43 components), and solid phase (orpiment, red arsenic, arsenolite, claudetite, arsenic, sulfur, sodium salts). Thermodynamic constants of the base components are contained in the Selektor database (they were borrowed from reference-books). The latter group includes 77 complexes labile in the solution but determining the solubility of arsenic and stability of its solid phases. Physicochemical modeling was performed in H2S (≥0.01 m, pH = 1–10), Na2S, and NaHS solutions at 25–250 °C and saturated-vapor pressure. It has been established that the dissolution of arsenic sulfide mineral phases in subneutral and alkaline solutions at low oxidation potential is favored by the formation of sulfoarsenides, which are more stable than arsenides and arsenates. Thermodynamic constants of functional complexes determining the orpiment solubility were calculated within the experimental error. It is shown that in hydrothermal iron-free systems with a low oxidation potential, the concentration of As in the solution decreases on cooling and with acidity increase.
Seismicity and seismoactive faults of Cuba
Authors: Cotilla Rodriguez M.O. , Franzke H.J. , Cordoba Barba D. 
Published: June 2007

Abstract
The first catalogue of active regional faults of Cuba is presented. The seismotectonic map of Cuba is a base for studying the seismicity in this region. Of the 30 faults studied, only twelve are active. The main seismotectonic structure is the Bartlett-Cayman fault system, which borders the eastern and southeastern seismotectonic units in this region. Approximately 70% of Cuban seismicity is concentrated here. The Cauto-Nipe, Cochinos and Nortecubana faults border other seismotectonic units. The Nortecubana fault is the only one associated with a tsunami. All the faults are segmented. The faults described are related to the current tectonic stress regime of the Northern Caribbean. All the available information (maps, sections and profiles, photos, geological and neotectonic data on seismicity and focal mechanisms) is supported by a GIS.
Modern accumulation rates of biogenic silica in Baikal bottom sediments: significance of diatom species composition
Authors: Levina O.V. , Karabanov E.B. 
Published: June 2007

Abstract
The modern distribution of biogenic silica (SiO2biog) in Baikal surface (0–0.2 and 0–0.5 cm) sediments, its mass accumulation rates (MAR), and the processes responsible for this distribution were studied. The contents of SiO2biog were determined in samples from 87 stations evenly distributed throughout the lake water area. These data were used to calculate the MAR of SiO2biog and compile SiO2biog and MAR distribution maps. The maps showed that the MAR varies significantly throughout the study area. Its highest values have been established in North Baikal. In Central and South Baikal the MAR values are much lower, and the minimum values are observed in the Selenga shoal. This MAR distribution pattern is consistent with the distribution of frustules of Aulacoseira baicalensis endemic diatoms throughout the surface sediments. Compared with other modern diatom species, this one has the most massive and heaviest frustules, which undergo the least dissolution when settling. This suggests that the above species plays a leading role in the accumulation of biogenic silica in modern Baikal bottom sediments, whereas the role of thin-walled species is minor because of their small mass and partial or complete dissolution in water on settling. Dilution of the sediments with terrigenous material is less significant for the SiO2biog accumulation.
Electromagnetic processes in a conducting magnetic casing string
Authors: Epov M.I. , Morozova G.M. , Antonov E.Yu. 
Published: June 2007

Abstract
We investigated the electromagnetic filed of a current loop in a conducting ferromagnetic cylinder for applications of casing monitoring in petroleum wells. We tested different transmitter-receiver configurations for excitation and recording of TEM and stationary magnetic fields, studied the responses to changes in electromagnetic and geometrical parameters of casing strings, and determined the intervals of highest sensitivity.