The influence of an organosulfonate on the reaction between Ellman's reagent and thiocholine

The aim of this work was to elucidate the effect of methanesulfonyl fluoride on the detection reaction for the determination of cholinesterase activity. The effect of methanesulfonyl fluoride was studied by monitoring the time course of the appearance and disappearance of the detection reaction product using a stopped-flow technique. The obtained experimental data were analyzed by progress curve analysis. It was found that the effect of methanesulfonyl fluoride results from a reaction between methanesulfonyl fluoride and the detection reaction product with the following rate constant: k1 = 5.33 x 10(-2) M-1s-1. In evaluating the effect of methanesulfonyl fluoride, the decomposition of this agent in water was included in the analysis because the decomposition considerably affected the reaction between methanesulfonyl fluoride and the product. The corresponding rate constant was found to be k2 = 4.9 x 10(-5) M-1s-1.     

Experimental evidence for the interaction of C-60 fullerene with lipid vesicle membranes

There are some molecular dynamic simulations but a paucity of experimental evidence of the effects of C-60 fullerene on lipid bilayers. The aim of this study is to assess the potential for disruption of the lipid bilayer by C-60 suspended in water. We selected a C-60 suspension that has previously been shown to provoke cell membrane destabilisation in vivo. Electromobility measurements show significant negative surface charge on the C-60 nanoparticles suspended in a glucose solution and a zeta potential of ?26 mV. The prevalent C-60 clusters have hydrodynamic radii of approximately 2 nm. Phase contrast microscopy and computer aided image analysis results show that C-60 causes shape transformations and rupture of unilamellar phospholipid vesicles, indicative of changes in their average mean curvature. Small-angle X-ray scattering reveals that C-60 provokes disruptions of external membranes of multilamellar vesicles only after freeze and thaw cycles. Here, the liposomes undergo breakage and annealing steps which increase the probability for fullerenes to insert into the MLVs. Our experimental findings confirm the potential of C-60 to reconstruct lipids in biological membranes. This research enhances our understanding of the impact of engineered nanoparticles on cell membranes.     

Relative efficiency of police directorates in Slovenia: A non-parametric analysis

The main purpose of the paper is to apply a non-parametric methodology for measuring public police performance in Slovenia. The paper considers how previous studies have modeled the role of policing in their specifications of inputs and output. In particular, the multiple-stage Data Envelopment Analysis (DEA) technique is presented and then applied to measure the relative efficiency of police-work-related data for eleven Police Directorates (PDs) in 2010 and also compared with the efficiency scores in 2005. The data obtained from the police databases is analyzed through the Frontier Analyst 4.0 and SPSS 19.0 statistical package software. The results show that the technical efficiency varies significantly across the police directorates and across the selected years, even when we allow for environmental factors and control for these non-discretionary inputs. Most police directorates in Slovenia could attain a higher output if they were fully efficient. Indeed, all of the inefficient police directorates can learn how to ensure a “good” performance from the efficient ones (i.e. the Maribor PD and the Novo mesto PD) by observing how they are processing their inputs and outputs. Finally, the empirical results of the paper are important indicators of the relative efficiency (or inefficiency) of police directorates that can serve as a guide to the General Police Directorate when further investigating how to enhance the performance efficiency of the various units.     

Dual representation of spatial rational Pythagorean-hodograph curves

In this paper, the dual representation of spatial parametric curves and its properties are studied. In particular, rational curves have a polynomial dual representation, which turns out to be both theoretically and computationally appropriate to tackle the main goal of the paper: spatial rational Pythagorean-hodograph curves (PH curves). The dual representation of a rational PH curve is generated here by a quaternion polynomial which defines the Euler–Rodrigues frame of a curve. Conditions which imply low degree dual form representation are considered in detail. In particular, a linear quaternion polynomial leads to cubic or reparameterized cubic polynomial PH curves. A quadratic quaternion polynomial generates a wider class of rational PH curves, and perhaps the most useful is the ten-parameter family of cubic rational PH curves, determined here in the closed form.     

Did Sleeping Papers in nursing research miss their target audience?

Scientometrics - Various factors have been attributed for delayed recognition of Sleeping Papers, for example introducing new technologies which didn’t yet exist, or proposing ideas that were...     

Small Reduction of the Piezoelectric d33 Response in Potassium Sodium Niobate Thick Films

We have investigated the electromechanical response of potassium sodium niobate (K_0.5Na_0.5NbO₃ or KNN) thick films. The high‐field strain hysteresis loops and weak‐field converse piezoelectric d₃₃ coefficient of the films were measured and compared with those of KNN bulk ceramics under the same electric field conditions. The converse d₃₃ values of the thick films and bulk ceramics were equal to 82.5 and 138 pm/V, respectively, at 0.4 kV/mm. The fundamental difference between the piezoelectric response of the KNN films and the ceramics was studied in terms of the effective (“clamped”) piezoelectric d₃₃ coefficient. The reduction in the piezoelectric d₃₃ coefficient of the KNN films, resulting from the clamping by the substrate, was compared to lead‐based ferroelectric thick films, including Pb(Zr,Ti)O₃ (PZT) and (1 ? x)Pb(Mg_1/3Nb_2/3)O₃?xPbTiO₃ (PMN‐PT). We propose a possible explanation, based on the particular elastic properties of KNN, for the small relative difference observed between the “clamped” and “unclamped” (“bulk”) d₃₃ of KNN, in comparison with lead‐based systems.     

Staying on your feet: the effectiveness of posture and handles in counteracting balance perturbation

Stairways, public transport and inclined walkways are often considered as sites with higher likelihood of falls due to a sudden loss of balance. Such sites are usually marked with warning signs, equipped with non-slip surfaces and handles or handrails to avert or decrease this likelihood. Especially, handles are supposed to provide additional support in cases of a sudden loss of balance. However, the mechanisms of using handles for balance at different heights are not yet fully disclosed. We simulated full body perturbations by applying an anterior force to the waist and investigated effectiveness and mechanisms of balance recovery in five different postures: step stance and normal stance with or without holding handles at different heights. Results indicate that both step stance and holding handles at different vertical positions sufficiently assist balance recovery, compared to normal stance. While there was no significant effect of handle in CoM displacement, the shoulder height handle required the lowest handle force, indicating a difference in using the handle.

Practitioner summary: To investigate handle use for balance recovery, we perturbed healthy young adults in different standing positions. Even though the use of different handles had a similar effect, the lowest forces were exerted on the shoulder height handle indicating a preferred handle position for balance recovery.

Abbreviation: AP: antero-posterior; CNS: Central nervous system; CoM: Center of Mass; CoMmax: Maximal displacement of the center of mass; CoP: Center of pressure; FHmax: Maximal resultant force exerted on the handle; hFHmax: Maximal horizontal force exerted on the handle; vFHmax; Maximal vertical force exerted on the handle; M1-M8: Perturbation force magnitude     

Numerical solving of the vibrational time-independent Schrödinger equation in one and two dimensions using the variational method

A program package for variational solving of the time-independent Schrödinger equation (SE) in one and two dimensions is described. The first part of the the program package includes the fitting program (FIT) with which the ab initio or DFT calculated points are fitted to a computationally inexpensive functional form. Proper fitting of the potential energy surface is crucial for the quality of the results. The second part of the package consists of a program for variational solving of the SE (2DSCHRODINGER) using either a shifted Gaussian basis set or the rectangular basis set proposed by Balint-Kurti and coworkers [J. Chem. Phys. 91 (1989) 3571]. The third part of the program package consists of the calculation of the expectation values, IR and Raman spectra XPECT), and the visualization of results (PLOT). The program package is applied to study a quantum harmonic oscillator and an intramolecular, strong hydrogen bond in picolinic acid N-oxide. For the former system analytical solutions exist, while for the latter system a comparison with the experimental data is made. The advantages and disadvantages of the applied methods are discussed.