Multiparticle clusters and carbon superstructure in martensite

On the basis of experimentally verified concentration expansion tensor values, stress induced two-particle C-C potentials have been calculated in harmonic approximation. A calculation method has been developed and expressions derived for the evaluation of multiparticle interaction potentials and cluster population. The temperature range of the applicability of the method has been estimated. On the basis of this method it has been demonstrated that in thermodynamic quasi-equilibrium, carbon atoms exist in clustered form. The clusters most frequently appearing at 300 K are of four- and five-particle type. The cluster configurations have been determined and the binding energy per atom has been estimated as about 0.5 eV. At 78 K, there exist practically only five-particle linear clusters situated along the tetragonal C axis. It has been postulated that a superstructure may exist in martensite with a binding energy per atom nearly four times higher than in the case of the above clusters. The presence of superstructure is associated with the formation of five-atom seeds in the form of pyramids having their basis in the (001) plane. The formation of seeds with different topology from the other clusters is associated with overcoming a potential barrier. The postulated form of ordering at low temperatures should exhibit high thermal stability with respect to ordering changes and order-disorder phase transitions, as well as to carbide formation.     

Numerical simulation of domestic wastewater sewer performance

The hydraulics of municipal sewers were considered with respect to flow rate fluctuations that sometimes cause accumulation and sometimes cause scouring of the sediments. The minimal slopes that would ensure self‐cleaning conditions once a day and the required capacity for the yearly maximum peak flows were calculated. The range of fluctuations in shear stresses along the sewer walls and in the wastewater table were observed and compared for sewers of different diameters. From these computations a simple design rule for predicting minimal slopes was developed.     

40 years of searching for the best computer system response time

For over 40 years, system response time has been a topic of interest and controversy in computer science. Since the late 1960s, the field has seen numerous studies conducted and articles written addressing the issue. Many factors were measured in these studies including: users’ accuracy and error rates with different levels of system response time, user performance speed and the efficiency of the commands used, how user interactions with the computer changed as a result of changes in system response time, how their bodies reacted physiologically to those same changes and even how happy, satisfied, anxious or annoyed they were as system response times changed.In this paper, we summarize the major issues in system response time research and look at what can be concluded from them. Generally, researchers have suggested specific response-time guidelines based on the complexity of the task or the type of interaction with the computer. We suggest that rather than system response time being task- or expectation-focused, instead interactions with a computer fall into two categories: control tasks and conversational tasks. For control tasks, immediate response times are necessary for optimal user performance whereas for conversational tasks, some delays may be necessary to maintain the optimal pacing of the on-going conversation. The location and duration of these delays will depend on both task complexity and user expectations. Future system response time research is needed to further quantify limits of delay detection, and the location and duration of inter-task delays to optimize user performance and satisfaction with computers.     

Template-directed synthesis of mesoporous silicas containing phosphonic acid derivatives in the surface layer

A template-directed process, using 1-dodecylamine as a template, is developed for the synthesis of mesoporous silicas containing the phosphonic acid derivatives ≡Si(CH₂)₂P(O)(OC₂H₅)₂ and ≡Si(CH₂)₃P(O)(CH₃)(ONa) in the surface layer. The porous materials obtained by removing the template with boiling methanol have specific surfaces of 854 and 505 m²/g, accessible pore volumes of 0.42 and 0.37 cm³/g, and pore diameters of 2.2 and 2.5 nm, respectively. As shown by scanning electron microscopy and x-ray diffraction, the mesoporous silicas are nonuniform in particle shape and size, and their structure is less ordered than that of classic mesoporous silicas, such as MCM-41. IR and ¹³C, ³¹P, and ²⁹Si CP/MAS NMR spectroscopy data indicate that, in the surface layer of the mesoporous silica prepared with the use of ≡Si(CH₂)₂P(O)(OC₂H₅)₂, the functional groups are present in the form of T ² and T ³ structural units. In addition, the surface layer contains alkoxy groups and water, which participates in hydrogen bonding.     

Highly dispersed green silicate and oxide pigments precipitated from model systems of postgalvanic waste

A procedure was worked out to obtain highly dispersed green silicate and oxide pigments precipitated from postgalvanic waste. The highly dispersed chromium(III) silicates and oxides were produced from the waste, originating from chromium plating, by reduction of Cr(VI) to Cr(III) employing various reducing agents. All the reductions were conducted in an acidic medium. Solutions of Cr(III), obtained in reducing processes, were employed to precipitate silicate pigments (using sodium metasilicate solution and containing mainly chromium(III) silicates) and oxide pigments (using sodium hydroxide and containing chromium(III) oxides). The precipitated silicates and oxides were subjected to a comprehensive physicochemical analysis (estimating bulk density, capacities to absorb water, dibutyl phthalate, paraffin oil, particle size distribution, and morphology of particle surface). Precipitation process (its parameters) and heating of the reactive mixture exerts a significant effect on the principal physicochemical properties of the pigments. The heating significantly affects first of all color shade of the obtained silicate and oxide pigments as well as their dispersion. Coprecipitated chromium(III) and iron(III) silicates exhibit a brownish color and a reasonably uniform character. Apart from primary agglomerates (in the range of 414-717 nm), they contain small amounts of secondary agglomerates (in the range of 4154-6445 nm). Best physicochemical parameters have been demonstrated by chromium pigments which have been precipitated from chromium solutions reduced using hydrogen peroxide. Chromium(III) oxides deserve particular distinction since their structure includes primary particles, primary agglomerates but is completely free of secondary agglomerates. The pigments manifest a brightly green color and a low capacity to absorb water (100 cm3 x 100 g(-1)). Application of hydrophobicity-inducing agents in the course of precipitation has corrected physicochemical parameters of both the oxides and silicates of chromium(II). Their bulk densities have been clearly decreased (to as low as below 250 g x L(-1) in the case of chromium(III) silicate), while capacities to absorb paraffin oil have increased to as much as 750 cm3 x 100 g(-1) for chromium(II) oxide. The respective particle size distribution has shown a tendency for disappearance of large accumulations of secondary agglomerates.     

Evaluation of the Optimal Manufacturing Protocols and Therapeutic Properties of Mesenchymal Stem/Stromal Cells Derived from Wharton’s Jelly

Wharton’s jelly (WJ) from the umbilical cord (UC) is a good source of mesenchymal stem/stromal cells (MSCs), which can be isolated and used in therapy. Current knowledge shows that even small changes in the cell environment may result in obtaining a subpopulation of cells with different therapeutic properties. For this reason, the conditions of UC transportation, cell isolation, and cultivation and the banking of cells destined for clinical use should be unified and optimized. In this project, we tried various protocols for cell vs. bioptat isolation, banking, and transport in order to determine the most optimal. The most efficient isolation method of WJ-MSCs was chopping the whole umbilical matrix with a scalpel after vessel and lining membrane removal. The optimal solution for short term cell transportation was a multi-electrolyte fluid without glucose. Considering the use of WJ-MSCs in cell therapies, it was important to investigate the soluble secretome of both WJ bioptats and WJ-MSCs. WJ-MSCs secreted higher levels of cytokines and chemokines than WJ bioptats. WJ-MSCs secreted HGF, CCL2, ICAM-1, BDNF, and VEGF. Since these cells might be used in treating neurodegenerative disorders, we investigated the impact of cerebrospinal fluid (CSF) on WJ-MSCs’ features. In the presence of CSF, the cells expressed consecutive neural markers both at the protein and gene level: nestin, β-III-tubulin, S-100-β, GFAP, and doublecortin. Based on the obtained results, a protocol for manufacturing an advanced-therapy medicinal product was composed.     

Heroin Regulates Orbitofrontal Circular RNAs

The number of drug overdose deaths involving opioids continues to rise in the United States. Many patients with opioid use disorder (OUD) that seek treatment still experience relapse. Perseverant opioid seeking behaviors represent a major challenge to treating OUD and additional therapeutic development will require insight into opioid-induced neurobiological adaptations. In this study, we explored the regulation of a novel class of RNAs, circular RNAs (circRNAs), by the addictive opioid heroin in the rat orbitofrontal cortex (OFC), a brain region that mediates behavioral responses to rewarding stimuli. Microarray analysis identified 76 OFC circRNAs significantly regulated in male rats after heroin self-administration. We evaluated the specificity of these findings by measuring heroin-associated circRNA expression in female rats after heroin self-administration and in rats that self-administered sucrose. We identify circGrin2b, circUbe2cp, circAnks1a, circAdcy5 and circSlc24A2 as heroin-responsive circRNAs in the OFC. Linear mRNA levels of heroin-associated circRNAs were unchanged except for Grin2b and Adcy5. An integrated bioinformatics analysis of regulated circRNAs identified microRNAs predicted to bind heroin-associated circRNAs and downstream targets of circRNA: microRNA sponging. Thus, heroin regulates the expression of OFC RNA splice variants that circularize and may impact cellular processes that contribute to the neurobiological adaptations that arise from chronic heroin exposure.     

Cellular protein interactions with herpes simplex virus type 1 oriS

The herpes simplex virus type 1 (HSV-1) origin of DNA replication, oriS, contains an AT-rich region and three highly homologous sequences, sites I, II, and III, identified as binding sites for the HSV-1 origin-binding protein (OBP). In the present study, interactions between specific oriS DNA sequences and proteins in uninfected cell extracts were characterized. The formation of one predominant protein-DNA complex, M, was demonstrated in gel shift assays following incubation of uninfected cell extracts with site I DNA. The cellular protein(s) that comprises complex M has been designated origin factor I (OF-I). The OF-I binding site was shown to partially overlap the OBP binding site within site I. Complexes with mobilities indistinguishable from that of complex M also formed with site II and III DNAs in gel shift assays. oriS-containing plasmid DNA mutated in the OF-I binding site exhibited reduced replication efficiency in transient assays, demonstrating a role for this site in oriS function. The OF-I binding site is highly homologous to binding sites for the cellular CCAAT DNA-binding proteins. The binding site for the CCAAT protein CP2 was found to compete for OF-I binding to site I DNA. These studies support a model involving the participation of cellular proteins in the initiation of HSV-1 DNA synthesis at oriS.     

Behavior ofTetranychus urticae toward essential oil mixtures from strawberry foliage

A standard essential oil mixture (SEOM) was formulated containing volatile compounds in the relative proportions found in the essential oil of the foliage of Citation, a strawberry cultivar relatively resistant toTetranychus urticae. Other mixtures contained varied levels, relative to the SEOM, oftrans-2-hexen-1-ol, nonanal, -terpineol, and methyl salicylate. The behavior ofT. urticae females in response to these mixtures at several concentrations in propylene glycol was studied in choice tube (preference) tests. Feeding effects were measured by incorporating the mixtures and individual components into sucrose with³²P. In the choice tube tests, mites were generally attracted by mixtures at concentrations of 0.1% or below unless the level of methyl salicylate was below 0.5 × that in the SEOM, or the level of nonanal was above that of the SEOM. When mixtures were incorporated into food, methyl-salicylate-stimulated feeding and nonanal levels were inversely related to the amount of food ingested.     

Fate,Transport and Effects of Pollutants Originating from Acid Mine Drainage in the Olifants River,South Africa

Concentrations of pollutants were measured in water, sediment and algal samples collected along a longitudinal gradient from a stretch of the Olifants River, South Africa, that receives acid mine drainage (AMD) from the Klipspruit River. The effects of AMD were determined through macroinvertebrate biotic indices (SASS5) and multivariate analysis of macroinvertebrate communities. The acidic Klipspruit River caused increased concentrations of total Al, Fe and Mn in the Olifants River. Upon mixing of the Klipspruit with that from the alkaline Olifants River, Al and Fe precipitate rapidly, leading to lower concentrations in the dissolved phase and higher concentrations in the suspended phase and in sediment at sites in close proximity to the confluence. Similarly, filamentous algae accumulated high concentrations of Al, Fe and Zn immediately after the confluence. Mn remains in the dissolved phase, and sediment and algal concentrations increase with increasing distance downstream. Metal speciation analysis indicate that Al is rapidly converted from more toxic forms (e.g. Al³⁺ and Al(OH)²⁺) to less toxic forms (e.g. Al(OH)₃(aq) and Al(OH)^4?). In contrast, Mn remains in the soluble Mn²⁺ form. Macroinvertebrate metrics and community structure showed clear signs of deterioration in water quality in the Olifants River downstream of the point of AMD input. While total TDS concentrations at all sites fall within ranges likely to affect macroinvertebrates, the relative composition of major ions changes as a result of AMD input, which may also account for the observed changes in macroinvertebrate communities. Further downstream, the Wilge River discharges into the Olifants River and significantly improves water quality downstream of the confluence. Future mining and development activities in the Wilge catchment should be carefully managed and monitored so as to ensure sufficient flows of acceptable quality to prevent further deterioration of water quality in the Olifants River and downstream reservoirs. Copyright © 2014 John Wiley & Sons, Ltd.