bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dosimetrical evaluation of Leksell Gamma Knife 4C radiosurgery unit
Authors: Sajeev Thomas , Mustafa Mohamed , Supe Sanjay 
Published: March 2012

Dosimetrical evaluation of Leksell Gamma Knife 4C radiosurgery unit
A number of experiments was performed using standard protocols, in order to evaluate the dosimetric accuracy of Leksell Gamma Knife 4C unit. Verification of the beam alignment has been performed for all collimators using solid plastic head phantom and Gafchromic™ type MD-55 films. The study showed a good agreement of Leksell Gammaplan calculated dose profiles with experimentally determined profiles in all three axes. Isocentric accuracy is verified using a specially machined cylindrical aluminium film holder tool made with very narrow geometric tolerances aligned between trunnions of 4 mm collimator. Considering all uncertainties in all three dimensions, the estimated accuracy of the unit was 0.1 mm. Dose rate at the centre point of the unit has been determined according to the IAEA, TRS-398 protocol, using Unidose-E (PTW-Freiburg, Germany) with a 0.125 cc ion chamber, over a period of 6 years. The study showed that the Leksell Gamma Knife 4C unit is excellent radiosurgical equipment with high accuracy and precision, which makes it possible to deliver larger doses of radiation, within the limits defined by national and international guidelines, applicable for stereotactic radiosurgery procedures.
Physical characteristics of photon beam from a CLINAC-DBX single energy accelerator
Authors: Umbarkar Rahul , Supe Sanjay , Pandey Manoy , Ashok Jayanty 
Published: March 2012

Physical characteristics of photon beam from a CLINAC-DBX single energy accelerator
Commissioning beam data are treated as a reference and ultimately used by treatment planning systems, therefore, it is vitally important that the collected data are of the highest quality, in order to avoid dosimetric and patient treatment errors that may subsequently lead to a poor radiation outcome. High-energy photon and electron beams from different accelerators of the same nominal energy may have different dosimetric characteristics due to differences in target and flattening filter materials, accelerator guide and collimator designs. In the present study, clinically pertinent data for the available photon energy were investigated. For making measurements in water, first time in India, a three dimensional radiation field analyzer RFA (CRS- Scan -O-Plan) was used. For absolute dosimetry and other measurements like relative output factors, wedge factors etc., a DOSE1 electrometer (Scanditronix Wellhofer) in a white polystyrene was employed. All the measured data were utilized as an input to the ECLIPSE treatment planning system for further clinical use.
Mathematical Model of Dynamic Work Conditions in the Measuring Chamber of an Air Gauge
Authors: Jermak Czeslaw , Spyra Andrzej , Rucki Miroslaw 
Published: March 2012

Mathematical Model of Dynamic Work Conditions in the Measuring Chamber of an Air Gauge
The goal of the proposed computational model was to evaluate the dynamical properties of air gauges in order to exploit them in such industrial applications as in-process control, form deviation measurement, dynamical measurement. The model is based on Reynolds equations complemented by the k-ε turbulence model. The boundary conditions were set in different areas (axis of the chamber, side surfaces, inlet pipeline and outlet cross-section) as Dirichlet's and Neumann's ones. The TDMA method was applied and the efficiency of the calculations was increased due to the "line-by-line" procedure. The proposed model proved to be accurate and useful for non-stationary two-dimensional flow through the air gauge measuring chamber.
Measurement Aspects of Genome Pattern Investigations - Hardware Implementation
Authors: Pułka Andrzej , Milik Adam 
Published: March 2012

Measurement Aspects of Genome Pattern Investigations - Hardware Implementation
The work presented in the paper concerns a very important problem of searching for string alignments. The authors show that the problem of a genome pattern alignment could be interpreted and defined as a measuring task, where the distance between two (or more) patterns is investigated. The problem originates from modern computation biology. Hardware-based implementations have been driving out software solutions in the field recently. The complex programmable devices have become very commonly applied. The paper introduces a new, optimized approach based on the Smith-Waterman dynamic programming algorithm. The original algorithm is modified in order to simplify data-path processing and take advantage of the properties offered by FPGA devices. The results obtained with the proposed methodology allow to reduce the size of the functional block and radically speed up the processing time. This approach is very competitive compared with other related works.
Mining of Coal Seams Under the Main Haulage Level / Podpatrové Dobývání Uhelných Slojí
Authors: Chovanec Josef , Urban Petr , Pěgřímek Ivo , Košnovský Vitězslav 
Published: March 2012

Abstract
The question of mining under the main haulage level as a way by which in some cases coal reserves can be effectively extracted is still discussed. The paper introduces advantages and disadvantages of this method. It presents examples of the bedding of a seam in a limited depth under level, for example 50 m, when the opening by the under level mining method is obviously more advantageous. Special attention is given to risks of ventilation short circuit which are higher in this method compared to classical opening. The paper also gives a brief economical reflection allowing to determine the efficiency of under level mining.
Value anchorage of social forecasting
Authors: Potůček Martin 
Published: March 2012

Hodnotové ukotvení sociálního prognózování
Stať rozebírá možné přístupy k identifikaci a uplatnění hodnotových východisek v sociálním prognózování. Zobecněním zkušeností z práce Centra pro sociální a ekonomické strategie FSV UK a s využitím mezinárodních inspirací dospívá k závěru, že kritérium kvality a udržitelnosti života a jeho ekonomická, sociální, environmentální a bezpečnostní dimenze poskytují solidnější základ pro hodnotové ukotvení sociálních prognóz, vizí a strategií, než by tomu bylo v případě dosud často užívaného indikátoru - hrubého domácího produktu.
Classical and Quantum Physics in Selected Economic Models
Authors: Drabik Ewa 
Published: March 2012

Classical and Quantum Physics in Selected Economic ModelsA growing number of economic phenomena are nowadays described with methods known in physics. The most frequently applied physical theories by economists are: (1) the universal gravitation law and (2) the first and second law of thermodynamics. Physical principles can also be applied to the theory of financial markets. Financial markets are composed of individual participants who may be seen to interact as particles in a physical system. This approach proposes a financial market model known as a minority game model in which securities and money are allocated on the basis of price fluctuations, and where selling is best option when the vast majority of investors tend to purchase goods or services, and vice versa. The players who end up being on the minority side win.The above applications of physical methods in economics are deeply rooted in classical physics. However, this paper aims to introduce the basic concepts of quantum mechanics to the process of economic phenomena modelling. Quantum mechanics is a theory describing the behaviour of microscopic objects and is grounded on the principle of wave-particle duality. It is assumed that quantum-scale objects at the same time exhibit both wave-like and particle-like properties. The key role in quantum mechanics is played by: (1) the Schrödinger equation describing the probability amplitude for the particle to be found in a given position and at a given time, and as (2) the Heisenberg uncertainty principle stating that certain pairs of physical properties cannot be economic applications of the Schrödinger equation as well as the Heisenberg uncertainty principle. We also try to describe the English auction by means the quantum mechanics methods.
Process Approach to Knowledge Management
Authors: Kotarba Marcin 
Published: March 2012

Process Approach to Knowledge ManagementThe article points out the limited availability of practical implementation guidelines, methods and tools as one of the core issues in the widespread usage of knowledge management (KM) in organizations. The process approach is proposed as an efficient way to understand the scope of knowledge management and to plan its development or improvement, in line with organizational strategy. The role of information technology (IT) in supporting knowledge management is emphasized and key functional groups of IT systems are listed. A sample section of the detailed process model is presented for the KM resource identification master process, with a BPMN graphical visualization. Both the process model and the detailed specification of IT systems supporting knowledge management are considered by the author as complex structures that require to be hosted in a dedicated support environment. Key assumptions of a tool, named KMBoost, are outlined to show how a simple, but interactive toolset can foster the understanding and usage of the KM process model. In the concluding remarks a high level SWOT analysis of the KM process model and the KMBoost tool is conducted.
Multicriteria Decision Making Model for the New Team Member Selection Based on Individual and Group-Related Factors
Authors: Wojnar Jakub 
Published: March 2012

Multicriteria Decision Making Model for the New Team Member Selection Based on Individual and Group-Related FactorsThis paper presents a novel approach to the team building emphasizing group-related attributes of potential candidates instead of focusing on their individual characteristics during the recruitment process. The main assumption is that the teamwork capabilities are equally if not more important than individual skills or competences when selecting new team member. Myers-Briggs Type Indicator is used for analyzing teamwork capabilities and multicriteria decision making model will be developed as a final solution.
Structures and Reactivity of Radicals Followed by Magnetic Resonance
Authors: Yurkovskaya Alexandra , Morozova Olga , Gescheidt Georg 
Published: March 2012

AbstractThis chapter introduces methods that allow real‐time observation of short‐lived radicals and radical ions at a nanosecond‐to‐microsecond time scale. CIDNP (Chemically induced dynamic nuclear polarization) and CIDEP (chemically induced dynamic electron polarization or time‐resolved EPR) provide structural details of short‐lived paramagnetic species and insights into reaction kinetics. The basis of these methods is introduced on a phenomenological basis and their scope is illustrated by several examples ranging from organic radicals to polymerization and biomolecular transformations. The aim of this chapter is to present the broad applicability of these methods in a variety of contexts.
Unusual Cyclizations
Authors: Gilmore Kerry , Alabugin Igor V. 
Published: March 2012

AbstractAlthough many radical cyclizations play prominent roles in organic synthesis and an ever increasing body of fundamental information aids in the constant development of new radical processes, a number of cyclization modes remain underrepresented. Such “unusual” gaps in the arsenal of available transformations exist for a variety of ring sizes. For example, even fast and stereoelectronically favorable 3‐exo and 4‐exo cyclizations are often rendered impossible by the high thermodynamic cost for the formation of strained small cycles. In contrast, 5‐endo cyclizations are exothermic but disfavored stereoelectronically and often slow. Moreover, even the most common five‐ or six‐membered rings are often made via an unusual class of cycloaromatization reactions where radical formation from a nonradical precursor is coupled with the cyclization step. A new set of problems appears for the formation of larger rings where the cyclizations are disfavored entropically.Additionally, certain factors disfavor even the well‐represented cyclization topologies, independent on the ring size. In particular, most cyclic closures involve carbon‐carbon bond formation via carbon radical addition to an alkene or alkyne, whereas radical ring closure via the formation of C‐heteroatom bonds are relatively scarce. We expand our discussion to radical cyclizations that proceed via CO and CN bond formation, which often provide an efficient approach to the construction of heterocycles.In our discussion, we highlight a number of factors that are useful for promoting unusual cyclizations: destabilization of reactants, stabilization of the cyclic products, electronic and conformational effects on the transition states, as well as coupling of thermodynamically unfavorable events with highly exothermic follow‐up steps.
Main‐Group Elements in Radical Chemistry
Authors: Baralle Alexandre , Baroudi Abdulkader , Daniel Marion , Fensterbank Louis , Goddard Jean‐Philippe , Lacôte Emmanuel , Larraufie Marie‐Hélène , Maestri Giovanni , Malacria Max , Ollivier Cyril 
Published: March 2012

AbstractThis article deals with the radical chemistry of main‐group elements, which has been a particularly active field over the last decade. More specifically, we have dealt with the recent synthetic advances involving nitrogen‐, oxygen‐, phosphorus‐, sulfur‐, and selenium‐centered radicals. Modes of generation of these highly reactive entities have witnessed tremendous developments and their various uses have been treated exhaustively. Mechanistic scenarios have been thoroughly discussed, and stereoselectivity issues, including asymmetric processes, have been addressed. Whenever possible, illustrative applications in the total synthesis of natural products or molecules with relevant properties have been introduced.
Xanthates and Related Derivatives as Radical Precursors
Authors: Zard Samir Z. 
Published: March 2012

Abstract
This chapter deals with the various radical reactions involving dithiocarbonates (xanthates) and related structures. It will revolve around two main topics: (i) cleavage of the CO bond and (ii) cleavage of the CS bond.
The first mode corresponds to the Barton–McCombie reaction and variants thereof. The mechanism of this important reaction is discussed in detail and then illustrated with a few varied examples taken from the recent literature (in order not to overlap too much with existing reviews). Modifications not using organotin hydrides are also described, with emphasis on the practical aspects. The incorporation of the Barton–McCombie process in various CC bond‐forming radical sequences is also be presented. Included in this part is an O → S radical chain rearrangement that is sometimes observed.
The second mode encompasses the degenerative fragmentation of xanthates. Radicals generated this way have a relatively long lifetime in the medium, allowing various transformations otherwise difficult to perform. Intermolecular additions to unactivated olefins are one such case. The possibility of using the adduct, itself a xanthate, for another radical sequence can also be exploited. Intra‐ and intermolecular additions to aromatic and heteroaromatic rings, as well as radical‐based modifications of the xanthate group, are other possibilities that are described and illustrated with examples.
Radical Enzymes
Authors: Buckel Wolfgang , Golding Bernard T. 
Published: March 2012

AbstractRadical enzymes catalyze reactions with intermediate radicals, which are not free but bound to the enzyme. The catalytic reactions comprise generation of a radical species that initiates formation of the substrate‐derived radical, followed by conversion to the product‐related radical, and either recycling or decomposition of the initiating radical with release of the product. These characteristics are illustrated with specific radical enzymes. Ribonucleotide reductases (RNRs) use a thiyl radical to enable a common reaction mechanism for the reduction of ribose. There are three classes of RNRs that differ in the manner of thiyl radical generation: use of coenzyme B12,S‐adenosylmethionine (SAM), or dioxygen with bi‐transition metal centers. Coenzyme B12‐dependent eliminases and mutases are like SAM radical enzymes in that they apply the same 5′‐deoxyadenosyl radical as initiating radical, which is also used by coenzyme B12‐ or SAM‐dependent RNRs. The SAM radical enzymes, which multiply in number, are involved in the maturation of enzymes and transfer of ribonucleic acids, as well as in the biosynthesis of many vitamins, coenzymes, and antibiotics. The 2‐ and 4‐hydroxyacyl‐coenzyme A (CoA) dehydratases contain a [4Fe–4S] cluster and utilize intermediate ketyl radicals, which are formed either by reduction or by combined oxidation/deprotonation of the substrates. Similar radical species participate in the reduction of benzoyl‐CoA and other aromatic compounds as well as in photolyases that repair DNA. Finally, flavin radical enzymes and two [4Fe–4S] cluster enzymes of the nonmevalonate pathway of isoprenoid biosynthesis are described. In conclusion, biotechnological applications and evolutionary aspects are discussed.
Supramolecular Radical Chemistry
Authors: Lucarini Marco 
Published: March 2012

Abstract
This report describes both the application of the concepts of supramolecular chemistry to control the reactivity of organic free radical and how electron paramagnetic resonance (EPR) methods have been extensively used for detecting and identifying noncovalent assemblies in solution and for clarifying their structure and properties. It shows how hydrogen bonding can modulate free radical properties; how halogen bonding can be used to prepare supramolecular structures containing nitroxide radicals with particular spin orientations; how the formation of host–guest complexes or the properties of self‐assembled monolayers can be investigated by EPR spectroscopy; and how radical cations can be employed to prepare very sophisticated molecular devices. Finally, a short description of the effects of confined space such as zeolites on radical–radical reactions is provided.
Photoinduced Electron Transfer from the Inorganic Core to the Organic Shell of Hybrid Core–Shell Nanoparticles: Impedance Spectroscopy
Authors: Guchhait Asim , Pal Amlan J. 
Published: March 2012

AbstractIn hybrid core–shell nanoparticles with inorganic nanocrystals in the core and organic molecules in the shell, photoinduced electron transfer occurs from the core to the shell. This leads to exciton dissociation through an ultrafast electron‐transfer process that results in charge separation and finally photocurrent in the external circuit in devices based on such core–shell nanoparticles. In this work, we have fabricated and characterized sandwiched devices based on a series of core–shell systems. From impedance spectroscopy, we have observed that photoinduced charge separation in core–shell systems is associated with a decrease in the device resistance and an increase in the dielectric constant of the active material. In the series of core–shell systems, we have observed a one‐to‐one correlation between the photoinduced electron‐transfer process and the changes in resistive and dielectric parameters upon illumination.
Clinical and biomarker profile of trauma-induced secondary cardiac injury
Authors: De'Ath H D , Rourke C , Davenport R , Manson J , Renfrew I , Uppal R , Davies L C , Brohi K 
Published: March 2012

AbstractBackgroundSecondary cardiac injury has been demonstrated in critical illness and is associated with worse outcomes. The aim of this study was to establish the existence of trauma-induced secondary cardiac injury, and investigate its impact on outcomes in injured patients.MethodsInjured adult patients eligible for enrolment in the Activation of Coagulation and Inflammation in Trauma 2 study, and admitted to the intensive care unit between January 2008 and January 2010, were selected retrospectively for the study. Markers of cardiac injury (brain natriuretic peptide (BNP), heart-type fatty acid binding protein (H-FABP) and troponin I) were measured on admission, and after 24 and 72 h in blood samples from injured patients. Individual records were reviewed for adverse cardiac events and death.ResultsDuring the study period, 135 patients were enrolled (106 male, 78·5 per cent) with a median age of 40 (range 16–89) years. Eighteen patients (13·3 per cent) had an adverse cardiac event during admission and these events were not associated with direct thoracic injury. The in-hospital mortality rate was higher among the adverse cardiac event cohort: 44 per cent (8 of 18) versus 17·1 per cent (20 of 117) (P = 0·008). Raised levels of H-FABP and BNP at 0, 24 and 72 h, and troponin I at 24 and 72 h, were associated with increased adverse cardiac events. BNP levels were higher in non-survivors on admission (median 550 versus 403 fmol/ml; P = 0·022), after 24 h (794 versus 567 fmol/ml; P = 0·033) and after 72 h (1043 versus 753 fmol/ml; P = 0·036), as were admission troponin I levels.ConclusionClinical and cardiac biomarker characteristics support the existence of trauma-induced secondary cardiac injury, which is associated with death, and unrelated to direct thoracic injury.
Biosynthesis of Xyrrolin, a New Cytotoxic Hybrid Polyketide/Non‐ribosomal Peptide Pyrroline with Anticancer Potential, in Xylaria sp. BCC 1067
Authors: Phonghanpot Suranat , Punya Juntira , Tachaleat Anuwat , Laoteng Kobkul , Bhavakul Vanida , Tanticharoen Morakot , Cheevadhanarak Supapon 
Published: March 2012

AbstractA gene from Xylaria sp. BCC 1067, pks3, that encodes a putative 3660‐residue hybrid polyketide synthase (PKS)/non‐ribosomal peptide synthetase (NRPS) was characterised by targeted gene disruption in combination with comprehensive product identification. Studies of the features of a corresponding mutant, YA3, allowed us to demonstrate that pks3 is responsible for the synthesis of a new pyrroline compound, named xyrrolin, in the wild‐type Xylaria sp. BCC 1067. The structure of xyrrolin was established by extensive spectroscopic and spectrometric analyses, including low‐ and high‐resolution MS, IR, 1H NMR, 13C NMR, 13C NMR with Dept135, HMQC 2D NMR, HMBC 2D NMR and COSY 2D NMR. On the basis of the Pks3 domain organisation and the chemical structure of xyrrolin, we proposed that biosynthesis of this compound requires the condensation of a tetraketide and an L‐serine unit, followed by Dieckmann or reductive cyclisation and enzymatic removal of ketone residue(s). Bioassays of the pure xyrrolin further displayed cytotoxicity against an oral cavity (KB) cancer cell line.