Smart systems for determination of drug’s solubility

The solubility of drugs is a crucial physicochemical property in the drug discovery or development process and for improving the bioavailability of drugs. There are various methods for evaluating the solubility of drugs including manual measurement methods, mathematical methods, and smart methods. Manual measurement and mathematical methods have some defects which make the smart systems more reliable and important in this field. In this review, various instruments used for the solubility determination, along with the smart systems, have been discussed. Mechanism and applications of each method have been elaborated in detail. Moreover, unique characteristics as well as some limitations of discussed methods are also described.     

Sources of information for innovation: the role of companies’ motivations

The paper analyses the information sources that companies use to innovate. The analysis compares two science-oriented sources of information (universities and public research institutes) with two market-oriented sources (clients and suppliers). The analysis demonstrates the importance of motivations as determinants of the sources of information used. Adding motivations to the established ‘structural’ explanations provides a new way of capturing companies’ search for information and emphasises the direction rather than the breadth of the search process. The results of this analysis also have implications both for policy-making and for companies’ managers, which are discussed in the paper’s conclusions.     

Application of Paris’ law for estimation of hydrogen-assisted fatigue crack growth

Based on the general form of Paris’ law a new method is proposed for estimating the rate of cracking of metals under Hydrogen-Assisted Fatigue. It is based on relating the fatigue crack growth rate of hydrogen embrittled metal to the fatigue crack growth rate of the metal without hydrogen embrittlement. One-dimensional hydrogen diffusion is assumed. Simulations using the proposed method on steel types X52, X70–80 and X80 are in agreement with published experimental tests results. The new method obviates numerical modelling of crack propagation and much reduces the computational costs.     

Building Block Approach’ for Structural Analysis of Thermoplastic Composite Components for Automotive Applications

Advanced thermoplastic prepreg composite materials stand out with regard to their ability to allow complex designs with high specific strength and stiffness. This makes them an excellent choice for lightweight automotive components to reduce mass and increase fuel efficiency, while maintaining the functionality of traditional thermosetting prepreg (and mechanical characteristics) and with a production cycle time and recyclability suited to mass production manufacturing. Currently, the aerospace and automotive sectors struggle to carry out accurate Finite Elements (FE) component analyses and in some cases are unable to validate the obtained results. In this study, structural Finite Elements Analysis (FEA) has been done on a thermoplastic fiber reinforced component designed and manufactured through an integrated injection molding process, which consists in thermoforming the prepreg laminate and overmolding the other parts. This process is usually referred to as hybrid molding, and has the provision to reinforce the zones subjected to additional stresses with thermoformed themoplastic prepreg as required and overmolded with a shortfiber thermoplastic resin in single process. This paper aims to establish an accurate predictive model on a rational basis and an innovative methodology for the structural analysis of thermoplastic composite components by comparison with the experimental tests results.     

Analysis of the magnetic field and studies of the beam dynamics for H− ions in the University of Manitoba cyclotron

Beam orbit dynamics investigations for H⁻ ions in the completely redesigned central region of the University of Manitoba cyclotron were carried out. The methods and the results of these studies are presented along with an analysis of the cyclotron magnetic field that was previously mapped in 1984.     

Application of CLTD’s for High Resolution Mass Identification and for Stopping Power Measurements of Heavy Ions

An array of calorimetric low temperature detectors (CLTD’s) for energy sensitive detection of heavy ions was combined with time-of-flight (TOF) detectors to obtain a detector system for high resolution mass identification of low energy heavy ions. In addition the same setup was used to prove the ability of CLTD’s to be used in electronic stopping power measurements for heavy ions in matter. Experiments with 50?MeV ⁶³Cu and ⁶⁵Cu ions at the tandem accelerator at the MPI at Heidelberg, and with 25 to 250?MeV ²³⁸U ions at the UNILAC accelerator at GSI at Darmstadt have been performed. For ^63,65Cu at 50?MeV a mass resolution of Δm(FWHM)=0.9?amu, and for ²³⁸U in an energy range of 65 to 150?MeV a resolution of Δm(FWHM)=1.28?amu, was obtained. The results for stopping powers of ²³⁸U in carbon and gold are presented and compared with theoretical predictions and data from the literature.     

Investigating different types of research collaboration and citation impact: a case study of Harvard University’s publications

This study aims to investigate the influence of different patterns of collaboration on the citation impact of Harvard University’s publications. Those documents published by researchers affiliated with Harvard University in WoS from 2000–2009, constituted the population of the research which was counted for 124,937 records. Based on the results, only 12% of Harvard publications were single author publications. Different patterns of collaboration were investigated in different subject fields. In all 22 examined fields, the number of co-authored publications is much higher than single author publications. In fact, more than 60% of all publications in each field are multi-author publications. Also, the normalized citation per paper for co-authored publications is higher than that of single author publications in all fields. In addition, the largest number of publications in all 22 fields were also published through inter-institutional collaboration and were as a result of collaboration among domestic researchers and not international ones. In general, the results of the study showed that there was a significant positive correlation between the number of authors and the number of citations in Harvard publications. In addition, publications with more number of institutions have received more number of citations, whereas publications with more number of foreign collaborators were not much highly cited.     

Comment on ‘Wigner equation of motion for time-dependent potentials’

Abstract

A correction is pointed out to a statement made by Galleani and Cohen (2002, J. mod. Optics, 49, 561) regarding the impossibility of deriving an equation of evolution for the Wigner function corresponding to the Schrödinger equation with a time-dependent potential.     

The inverse problem of Lagrangian mechanics for Meshchersky’s equation

Variable-mass systems are not included in the conventional domain of the analytical and variational methods of classical mechanics. This is due to the fact that the fundamental principles of mechanics were primarily conceived for constant-mass systems. In the present article, an analytical and variational formulation for variable-mass systems will be proposed. This will be done from the solution of the here called ‘inverse problem of Lagrangian mechanics for Meshchersky’s equation’. The first problem of this nature was posed in 1887, by Helmholtz (J. reine angew. Math. 100:137–166, 1887). Investigations on the matter are far from being exhausted. Within mechanics, it means the construction of a Lagrangian from a given equation of motion. To the authors’ best knowledge, aiming at general results, the inverse problem of Lagrangian mechanics has not been properly connected to Meshchersky’s equation yet. This is the main goal of this article. We will address the issue by assuming that mass depends on generalized coordinate, generalized velocity and on time. After the construction of a Lagrangian from Meshchersky’s equation, a general and unifying mathematical formulation will emerge in accordance. Therefore, variable-mass systems will be accommodated at the level of analytical mechanics. A variational formulation, which will be written via a principle of stationary action, and a Hamiltonian formulation will be both stated. The latter could be read as the ‘Hamiltonization’ of variable-mass systems from the solution of the inverse problem of Lagrangian mechanics. An energy-like conservation law will naturally appear from the simplification of the general theory to the case of a system with mass solely dependent on a generalized coordinate.     

Hill’s lemma for the average-field theory of Cosserat continuum

There are two typical definitions for the macroscopic average couple stress tensor in the literature, which brings confusion and difficulty to the establishment of Hill’s lemma for heterogeneous Cosserat continuum. Besides, some boundary conditions on the representative volume element (RVE) commonly used in the homogenization method cannot be properly determined by the existing version of Hill’s lemma of Cosserat continuum. To deal with these issues, Hill’s lemma for micro-macro homogenization modeling of Cosserat continuum is further investigated in the frame of the average-field theory in this paper. An intermediate form of Hill’s lemma is constructed in which the micromechanically based definition of the average couple stress tensor is not specified. By substituting two existing definitions of the average couple stress tensor into the presented intermediate form, not only the previous version of Hill’s lemma is derived, but also a new version of Hill’s lemma is obtained. According to the new version of Hill’s lemma, more versatile RVE boundary conditions in the strong form can be properly given, and the periodic RVE boundary conditions in the weak form are also constructed.     

Optimal way for choosing parameters of spacecraft’s screen-vacuum heat insulation

The heat transfer in multiple plate sandwiches of spacecraft’s screen-vacuum heat insulation is simulated for determining the characteristics of heat shielding against long-term solar heat flux. To choose optimal characteristics of heat shielding, it is necessary to determine precisely the number of plates and their peculiarities. The new, absolutely stable method for solving numerically heat transfer problems is presented. We obtain results showing that the screen-vacuum insulation is characterized by low heating-up inertance that is unacceptable. To remove this effect, the inertial heat shielding is used on the internal surface of the heat shielding and its state is examined.     

An algebraic theory of contrasts for Neyman’s modified chi-square statistic

Behaviormetrika - The use of Pearson’s chi-square goodness of fit statistic is well established in the analysis of contingency tables. This statistic measures the overall discrepancy between...     

Identification of functional parameters for the classification of older female fallers and prediction of ‘first-time’ fallers

Falls remain a challenge for ageing societies. Strong evidence indicates that a previous fall is the strongest single screening indicator for a subsequent fall and the need for assessing fall risk without accounting for fall history is therefore imperative. Testing in three functional domains (using a total 92 measures) were completed in 84 older women (60–85 years of age), including muscular control, standing balance, and mean and variability of gait. Participants were retrospectively classified as fallers (n = 38) or non-fallers (n = 42) and additionally in a prospective manner to identify first-time fallers (FTFs) (n = 6) within a 12-month follow-up period. Principal component analysis revealed that seven components derived from the 92 functional measures are sufficient to depict the spectrum of functional performance. Inclusion of only three components, related to mean and temporal variability of walking, allowed classification of fallers and non-fallers with a sensitivity and specificity of 74% and 76%, respectively. Furthermore, the results indicate that FTFs show a tendency towards the performance of fallers, even before their first fall occurs. This study suggests that temporal variability and mean spatial parameters of gait are the only functional components among the 92 measures tested that differentiate fallers from non-fallers, and could therefore show efficacy in clinical screening programmes for assessing risk of first-time falling.