Breakage probability of irregularly shaped particles

The investigation of breakage probability by compression of single particles was carried out. The spherical glass particles and irregularly shaped particles of NaCl, sugar, basalt and marble were subjected to a breakage test. The breakage test includes the compression up to breakage of 100 particles to obtain the distribution of the breakage probability depending on the breakage force or compression work. The breakage test was conducted for five particle size fractions from each individual material, at two stressing rates. Thus obtained 50 breakage force distributions and corresponding 50 breakage work distributions were fitted with log-normal distribution function.Usually, the breakage probability distribution can be found by means of stress or energy approach. The first one uses the stress to calculate the breakage probability distribution. The second approach uses the mass-related work done to break the particle. We prefer to use the breakage force and energy as essential variables. The correlation between the force and energy at their breakage points is obtained by integrating the characteristic force–displacement curve, i.e. the constitutive function of elastic–plastic mechanical behavior of the particle. The irregularly shaped particle is approximated by comparatively “large” hemispherical asperities. In terms of elastic–plastic deformation of the contacting asperities with the plate, a transition from elastic to inelastic deformation behavior was considered. Thus, one may apply the model of soft contact behavior of comparatively stiff hemispheres. Based on this model a relationship between the breakage force distributions and corresponding energy distributions was analyzed. Every tested material exhibits a linear relationship between average breakage energy and average breakage force calculated for every size fraction.For future consideration both force and energy distributions were normalized by division by average force or energy, consequently. The relationship between the fit parameters of normalized energy distribution and corresponding fit parameters of normalized force distribution was established. The mean value and standard deviation of normalized force distribution can be found from mean value and standard deviation of normalized energy distribution by means of system of two linear equations. The coefficients of those linear equations remain the same for all of the above tested materials; particle size fractions and stressing rates. As a result the simple transformation algorithm of distributions is developed. According to this algorithm the force distribution can be transformed into energy distribution and vice versa.     

An adsorptive transfer technique coupled with brdicka reaction to reveal the importance of metallothionein in chemotherapy with platinum based cytostatics

The drugs based on platinum metals represent one of the oldest, but also one of the most effective groups of chemotherapeutic agents. Thanks to many clinical studies it is known that resistance of tumor cells to drugs is a frequent cause of chemotherapy failure. With regard to platinum based drugs, multidrug resistance can also be connected with increased expression of low-molecular weight protein metallothionein (MT). This study aimed at investigating the interactions of MT with cisplatin or carboplatin, using the adsorptive transfer technique coupled with differential pulse voltammetry Brdicka reaction (AdTS DPV Brdicka reaction), and a comparison of in vitro results with results obtained in vivo. The results obtained from the in vitro study show a strong affinity between platinum based drugs and MT. Further, we analyzed extracts of neuroblastoma cell lines treated with cisplatin or carboplatin. It is clear that neuroblastoma UKF-NB-4 cisplatin-resistant and cisplatin-sensitive cell lines unlikely respond to the presence of the platinum-based cytostatics cisplatin and carboplatin. Finally, we determined the level of MT in samples from rabbits treated with carboplatin and patients with retinoblastoma treated with the same drug.     

Arylethyne Bromoboration–Negishi Coupling Route to E‐ or Z‐Aryl‐Substituted Trisubstituted Alkenes of ≥98% Isomeric Purity. New Horizon in the Highly Selective Synthesis of Trisubstituted Alkenes

The hitherto unprecedented palladium‐catalyzed cross‐coupling of (Z)‐β‐bromo‐β‐arylethenylboranes can be made to proceed satisfactorily through (1) the use of highly catalytically active bis(tri‐tert‐butylphosphine)palladium or dichloro[N,N‐bis‐(2,6‐diisopropylphenyl)imidazol‐2‐yl](m‐chloropyridine)palladium and (2) conversion of the dibromoboryl group to the (pinacol)boryl group. Thus, a wide variety of carbon groups can be used to substitute bromine in ≥98% stereo‐ and regioselectivity, while suppressing the otherwise dominant β‐debromoboration. Together with the alkylethyne‐based protocols, the alkyne bromoboration–Negishi coupling tandem process has emerged as the most widely applicable and highly selective route to trisubstituted alkenes including those that are otherwise difficult to access.     

Advanced methods for the estimation of an unknown projection from a map

This article presents three new methods (M5, M6, M7) for the estimation of an unknown map projection and its parameters. Such an analysis is beneficial and interesting for historic, old, or current maps without information about the map projection; it could improve their georeference. The location similarity approach takes into account the residuals on the corresponding features; the minimum is found using the non-linear least squares. For the shape similarity approach, the minimized objective function ? takes into account the spatial distribution of the features, together with the shapes of the meridians, parallels and other 0D-2D elements. Due to the non-convexity and discontinuity, its global minimum is determined using the global optimization, represented by the differential evolution. The constant values of projection φ _k , λ _k , φ ₁, λ ₀, and map constants R,ΔX,ΔY, α (in relation to which the methods are invariant) are estimated. All methods are compared and the results are presented for the synthetic data as well as for 8 early maps from the Map Collection of the Charles University and the David Rumsay Map Collection. The proposed algorithms have been implemented in the new version of the detectproj software.     

Glial-Neuronal Interactions in Pathogenesis and Treatment of Spinal Cord Injury

Traumatic spinal cord injury (SCI) elicits an acute inflammatory response which comprises numerous cell populations. It is driven by the immediate response of macrophages and microglia, which triggers activation of genes responsible for the dysregulated microenvironment within the lesion site and in the spinal cord parenchyma immediately adjacent to the lesion. Recently published data indicate that microglia induces astrocyte activation and determines the fate of astrocytes. Conversely, astrocytes have the potency to trigger microglial activation and control their cellular functions. Here we review current information about the release of diverse signaling molecules (pro-inflammatory vs. anti-inflammatory) in individual cell phenotypes (microglia, astrocytes, blood inflammatory cells) in acute and subacute SCI stages, and how they contribute to delayed neuronal death in the surrounding spinal cord tissue which is spared and functional but reactive. In addition, temporal correlation in progressive degeneration of neurons and astrocytes and their functional interactions after SCI are discussed. Finally, the review highlights the time-dependent transformation of reactive microglia and astrocytes into their neuroprotective phenotypes (M2a, M2c and A2) which are crucial for spontaneous post-SCI locomotor recovery. We also provide suggestions on how to modulate the inflammation and discuss key therapeutic approaches leading to better functional outcome after SCI.     

Multifunctional Gadolinium‐Doped Mesoporous TiO2 Nanobeads: Photoluminescence,Enhanced Spin Relaxation,and Reactive Oxygen Species Photogeneration,Beneficial for Cancer Diagnosis and Treatment

Materials with controllable multifunctional abilities for optical imaging (OI) and magnetic resonant imaging (MRI) that also can be used in photodynamic therapy are very interesting for future applications. Mesoporous TiO₂ sub‐micrometer particles are doped with gadolinium to improve photoluminescence functionality and spin relaxation for MRI, with the added benefit of enhanced generation of reactive oxygen species (ROS). The Gd‐doped TiO₂ exhibits red emission at 637 nm that is beneficial for OI and significantly improves MRI relaxation times, with a beneficial decrease in spin–lattice and spin–spin relaxation times. Density functional theory calculations show that Gd³⁺ ions introduce impurity energy levels inside the bandgap of anatase TiO₂, and also create dipoles that are beneficial for charge separation and decreased electron–hole recombination in the doped lattice. The Gd‐doped TiO₂ nanobeads (NBs) show enhanced ability for ROS monitored via ^?OH radical photogeneration, in comparison with undoped TiO₂ nanobeads and TiO₂ P25, for Gd‐doping up to 10%. Cellular internalization and biocompatibility of TiO₂@x Gd NBs are tested in vitro on MG‐63 human osteosarcoma cells, showing full biocompatibility. After photoactivation of the particles, anticancer trace by means of ROS photogeneration is observed just after 3 min irradiation.     

Water quality and diatom communities in two catalan rivers (N.E. Spain)

Benthic diatom assemblages have been used to evaluate the water quality of two rivers subjected to marked human influences. These rivers, the Llobregat and the Ter, are located in N.E. Spain, and supply water for industrial, agricultural and urban requirements of roughly three million people. The diatom communities in the headwaters are similar in both rivers (Achnanthes minutissima, Cymbella ventricosa, Gomphonema anguslatum). Species of Navicula, Nitzschia and Gomphonema develop in the middle reaches of both rivers when not disrupted by extraneous factors. In the river Ter significant pollution modifies this community and Nitzschia palea, Nitzschia gandersheimiensis and Gomphonema parvulum appear as the most tolerant species. In the Llobregat, the pollution from the salt mine operations also modifies the diatom assemblage and Nitzschia frustulum, Surirella ovata, Navicula atomus are the most abundant species. Reservoirs in the river Ter improve the quality of water and a community of Fragilaria sp. pl. becomes dominant downstream.     

Failure Resistance of the Historic Stone Bridge Structure of Charles Bridge. I: Susceptibility to Nonstress Effects

The monitoring of deformations of the stone structure of Charles Bridge in Prague proved the gravity and relevance of nonstress effects (temperature, moisture content) on cyclic deformations and permanent strain accompanied by a gradual disintegration of its stone masonry, growing tilt of the breast walls, and development of cracks in the masonry of the stone bridge structure. Each deformation cycle is accompanied by a gradual growth in permanent deformations. The “unmanifested” primary deformation due to, e.g., a temperature change causes a mechanical state of tension, and it is mainly the tensile stresses thus arising that contribute to the development of tensile cracks in the stone masonry.