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The aim of this study was to demonstrate the advantages and the method of application of the SHS process in the manufacture of (NiAl/Ni3Al)/TiB2 composites. A comparison was made between sinters manufactured by FAST/SPS using two different routes to process the substrates, which formed the composite matrix. The evaluation criteria were based on measurements of selected physical, mechanical, and tribological properties, and on microstructure examinations. The evaluation has indicated a preferable method for the manufacture of composites, where the SHS reaction takes place during compaction of the powder mixture. This produces a sinter characterized not only by the high degree of sintering, and high values of the Young’s modulus and HV1 hardness, but also by the satisfactory resistance to tribological wear. Additionally, the use of this process saves energy and reduces product-making cost, owing to a less expensive technique of making individual substrates.

RATIONALE: “Bath salts” preparations often contain combinations of synthetic cathinones (e.g., 3,4methylenedioxymethcathinone [methylone], 3,4-methylenedioxypyrovalerone [MDPV]) and caffeine, and evidence suggests that mixtures of synthetic cathinones and caffeine (e.g., MDPV+caffeine or methylone+caffeine) can be more potent and/or effective reinforcers than predicted for an additive interaction. OBJECTIVE: To use demand curve analyses to compare the reinforcing effectiveness of MDPV and methylone to mixtures of MDPV+caffeine and methylone+caffeine. METHODS: Male Sprague-Dawley rats acquired methylone self-administration (0.32 mg/kg/inf) under a fixed ratio (FR) 1 schedule of reinforcement, and generated full dose-response curves for methylone (0.01–1 mg/kg/inf) under an FR5 schedule of reinforcement. Demand curves were then obtained for methylone, MDPV, caffeine, and methylone+caffeine and MDPV+caffeine mixtures by increasing the FR across sessions according to the following series: 3, 10, 18, 32, 56, 100, 178, etc. RESULTS: Self-administration of methylone was rapidly acquired by 87.5% of rats and was maintained across a range of doses, producing an inverted U-shaped dose-response curve. Rank order demand for the individual constituents was MDPV>methylone>caffeine. Demand for the 3:1 (but not 10:1) methylone+caffeine mixture was greater than that for methylone alone, and demand for MDPV alone was similar to both MDPV+caffeine mixtures evaluated. CONCLUSIONS: These studies provide additional evidence that although methylone is an effective reinforcer, combining methylone with caffeine results in an enhanced reinforcing effectiveness compared to methylone alone. Thus, abused “bath salts” preparations containing synthetic cathinones and caffeine may have higher abuse liability than preparations containing only synthetic cathinones.

Synthetic cathinones are common constituents of abused “bath salts” preparations and represent a large family of structurally related compounds that function as cocaine-like inhibitors or amphetamine-like substrates of dopamine (DAT), norepinephrine (NET), and serotonin (SERT) transporters. Preclinical evidence suggests that some cathinones (e.g., MDPV and α-PVP) are more effective reinforcers than prototypical stimulant drugs of abuse, such as cocaine or methamphetamine. Although the reinforcing potency of these cathinones is related to their potency to inhibit DAT, less is known about the pharmacological determinants of their unusually high reinforcing effectiveness. To this end, we tested the hypothesis that reinforcing effectiveness of cathinone stimulants is positively correlated with their selectivity for DAT relative to SERT. Uptake inhibition assays in rat brain synaptosomes were used to directly compare the potency of MDPV, MDPBP, MDPPP, α-PVP, α-PPP, and cocaine at DAT, NET, and SERT, whereas intravenous self-administration in rats was used to quantify relative reinforcing effectiveness of the drugs using progressive ratio (PR) and behavioral economic procedures. All cathinones were more potent at DAT than NET or SERT, with a rank order for selectivity at DAT over SERT of α-PVP > α-PPP > MDPV > MDPBP > MDPPP > cocaine. These synthetic cathinones were more effective reinforcers than cocaine, and the measures of reinforcing effectiveness determined by PR and demand curve analyses were highly correlated with selectivity for DAT over SERT. Together, these studies provide strong and convergent evidence that the abuse potential of stimulant drugs is mediated by uptake inhibition at DAT, with activity at SERT serving as a negative modulator of reinforcing effectiveness.

We describe for the first time a method that utilizes microscale thermophoresis (MST) technology to determine polyclonal antibody affinities to small molecules. Using a novel type of heterologous MST, we have accurately measured a solution-based binding affinity of serum antibodies to heroin which was previously impossible with other currently available methods. Moreover, this mismatch approach (i.e., using a cross-reactive hapten tracer) has never been reported in the literature. When compared with equilibrium dialysis combined with ultra-performance liquid chromatography/tandem mass spectrometry (ED-UPLC/MS/MS), this novel MST method yields similar binding affinity values for polyclonal antibodies to the major heroin metabolites 6-AM and morphine. Additionally, we herein report the method of synthesis of this novel cross-reactive hapten, MorHap-acetamide—a useful analog for the study of heroin hapten–antibody interactions. Using heterologous MST, we were able to determine the affinities, down to nanomolar accuracies, of polyclonal antibodies to various abused opioids. While optimizing this method, we further discovered that heroin is protected from serum esterase degradation by the presence of these antibodies in a concentration-dependent manner. Lastly, using affinity data for a number of structurally different opioids, we were able to dissect the moieties that are crucial to antibody binding. The novel MST method that is presented herein can be extended to the analysis of any ligand that is prone to degradation and can be applied not only to the development of vaccines to substances of abuse but also to the analysis of small molecule/protein interactions in the presence of serum. Graphical abstractStrategy for the determination of hapten-induced antibody affinities using Microscale thermophoresis Electronic supplementary material The online version of this article (10.1007/s00216-018-1060-4) contains supplementary material, which is available to authorized users.

3,4-Methylenedioxymethamphetamine (MDMA) increases sociality in humans and animals. Release of serotonin (5-HT) is thought to have an important role in the increase in social behaviors, but the mechanisms underlying these effects are poorly understood. Despite the advantages of nonhuman primate models, no studies have examined the mechanisms of the social effects of MDMA in nonhuman primates. The behavior and vocalizations of four group-housed squirrel monkeys were examined following administration of MDMA, its enantiomers, and methamphetamine. 5-HT receptor antagonists and agonists were given as drug pretreatments. Data were analyzed using linear mixed-effects models. MDMA and its enantiomers increased affiliative social behaviors and vocalizations, whereas methamphetamine had only modest effects on affiliative behaviors. Pretreatment with a 5-HT2A receptor antagonist and a 5-HT2C receptor agonist attenuated the MDMA-induced increase in social behaviors, while a 5-HT1A receptor antagonist did not alter affiliative vocalizations and increased MDMA-induced social contact. Nonhuman primates show MDMA-specific increases in affiliative social behaviors following MDMA administration, in concordance with human and rodent studies. MDMA-induced increases in social behaviors are 5-HT2A, but not 5-HT1A, receptor dependent. Understanding the neurochemical mechanisms mediating the prosocial effects of MDMA could help in the development of novel therapeutics with the unique social effects of MDMA but fewer of its limitations.

Arbuscular mycorrhiza (AM) development in five non-nodulating pea (Pisum sativum L.) mutants (sym7, sym11, sym14, sym34, sym38) grown in nurse pots was analyzed at the early stages of colonization by Rhizophagus irregularis. Abundance of external mycelium attached to the root surface and parameters of internal fungal colonization, i.e. intensity of colonization, and arbuscule and vesicle/spore abundance, were evaluated. Mutations in SYM7 (putative ortholog of NSP2, ‘nodulation signaling pathway 2’), SYM11, and SYM14 genes resulted in considerable increase in root surface colonization and a substantial decrease in internal colonization as compared to corresponding wild-type pea lines (wt). In addition, the mutants sym7 and sym11 displayed a highly reduced amount of arbuscules. In contrast, plants mutated for the SYM34 gene displayed strongly reduced root surface colonization. The mutant sym34 also had strongly reduced internal colonization after 10 days of growth, but did not differ from wt 10 days later. The sym38 mutant did not differ from wt. These data indicate that all pea genes analyzed, except SYM38, are essential for both nodule and AM development. The phenotype of sym34 suggested that the pea SYM34 gene is an ortholog of the Medicago truncatula NSP1 (‘nodulation signaling pathway 1’), and early stop codons were in fact detected in an NSP1 homologous sequence of two sym34 mutants. In addition, full co-segregation of the allelic states of a molecular marker representing a polymorphic fragment of the hypothetical pea NSP1 gene, together with the nodulation phenotype of 50 F2 plants, support our hypothesis. A possible explanation for the different AM phenotypes of sym7 and sym34 is given.

Composites reinforced with 8 vol% TiB2 were subjected to the consolidation process by spark plasma sintering (SPS). The results show that the addition of boron (1 vol%) introduced to the steel matrix has a significant effect on the composite microstructure, as well as physical, mechanical and tribological properties. The full density of 97–99% was obtained in the composites sintered at a temperature of 1100∘C. The steel–8% TiB2–1% B composite sintered at 1100∘C for 30 min was characterized by the highest microhardness (465 HV0.3) and Young’s modulus (229 GPa), combined with the best compressive strength (1150 MPa) and abrasive wear resistance (μ = 0.25 and W V(disc) = 207.78 × 10−6 mm3 N−1m−1). The microstructure and chemical composition were examined by scanning electron microscopy and transmission electron microscopy. The examinations have revealed the presence of numerous fine complex borides in the microstructure of the steel–8% TiB2 and steel–8% TiB2–1% B composites.

The AISI316L stainless steel composites reinforced with 2, 4, 6, and 8 vol% titanium diboride (TiB2) particles were sintered by the high pressure-high temperature method. Ball-on-disk method was carried out to study wear behavior of the composites. Tests were carried out at room temperature. The TiB2 particles improved the hardness and tribological properties of the composites. The friction coefficient of the composites decreased with the increasing content of TiB2. The reduction of the wear rate with the increasing of the content of TiB2 particles in the steel matrix was also observed. It is demonstrated that the friction coefficient of composites with the same content of TiB2 particles depend on the sintering conditions.

Chain geometry associated with an affine group and with a linear group is studied. In particular, closely related to the respective chain geometries affine partial linear spaces and generalizations of sliced spaces are defined. The automorphisms of thus obtained structures are determined.

Human linkage and association studies suggest a gene(s) for nonsyndromic cleft lip with or without cleft palate (CL/P) on chromosome 4q31-q32 at or near the platelet-derived growth factor-C (PDGF-C) locus. The mouse Pdgfc(-/-) knockout shows that PDGF-C is essential for palatogenesis. To evaluate the role of PDGF-C in human clefting, we performed sequence analysis and SNP genotyping using 1048 multiplex CL/P families and 1000 case-control samples from multiple geographic origins. No coding region mutations were identified, but a novel -986 CT SNP (rs28999109) was significantly associated with CL/P (P=0.01) in cases from Chinese families yielding evidence of linkage to 4q31-q32. Significant or near-significant association was also seen for this and several other PDGF-C SNPs in families from the United States, Spain, India, Turkey, China, and Colombia, whereas no association was seen in families from the Philippines, and Guatemala, and case-controls from Brazil. The -986T allele abolished six overlapping potential transcription regulatory motifs. Transfection assays of PDGF-C promoter reporter constructs show that the -986T allele is associated with a significant decrease (up to 80%) of PDGF-C gene promoter activity. This functional polymorphism acting on a susceptible genetic background may represent a component of human CL/P etiology.

The subject of the work was to study the effect of Si alloying addition to the aluminum on the bond strength properties, wettability, and structure of interface in the AlSi11/Al2O3 joints. Taking advantage of the sessile drop method, the wetting of alumina substrates by liquid AlSi11 alloy or Al was studied. The sessile drop tests were carried out in the temperature range between 1023 and 1223 K, under a vacuum of 0.2 mPa for 30 or 120 minutes of contact. The shear strength results demonstrated significant improvement of shear strength of AlSi11/Al2O3 joints due to the application of silicon as an alloying addition to aluminum. Microstructural investigations of interface indicated that the silicon crystals were formed at the AlSi11/Al2O3 interface, which influenced the strengthening of these joints. A conclusion could be drawn, that the interface structure influenced the increase of the shear strength of AlSi11/Al2O3 joints.

The spectrum and mode shapes of the natural elastic vibrations of disk-shaped ZnSe crystals are studied. Twin modes are identified which are closely related to the stress-strain state of the material.

Metal contacts using doped self-aligning metallization to [100] and [111] p-type silicon were investigated. Contacts formed in this manner allow the formation of a pn-junction and provide front metallization for photovoltaic applications. Formulated screen-printable thick films were annealed above Ag/Si eutectic temperature of 830 °C. The annealing process resulted in a junction depth of 0.3–1.1 μm with improved Ag/Si metal contacts due to the reduction of parasitic native oxide layer via the use of a wetting agent. The technique inhibits shunts (high conductivity paths through the solar cell pn-junction caused by excessive metal penetration) due to limited solubility of Ag in Si. The technique also reduces series resistance (a parasitic resistance due to surface states that also limit solar cell performance) due to a robust thermal processing window. The use of magnesium (Mg) as a wetting agent in the thick film Ag matrix was explored. We observed a correlation between increased wetting and improved dark saturation current J02 in the absence of a pre-existing junction.

A single-step diffusion followed by precise etching of the diffused layer has been developed to obtain a diffusion profile appropriate for high-efficiency GaSb thermophotovoltaic (TPV) cells. The junction depth was controlled through monitoring of light current-voltage (I–V) curves (photovoltaic response) during the post-diffusion emitter-etching process. The measured photoresponses (prior to device fabrication) have been correlated with the quantum efficiencies (QEs) and the open-circuit voltages in the fabricated devices. An optimum junction depth for obtaining the highest QE and open-circuit voltage is presented based on diffusion lengths (or minority carrier lifetimes), carrier mobility, and the typical diffused impurity profile in GaSb.

Data are presented on the spectral dependence of steady-state photoconductivity for Cd1 - xZnxTe (x = 0.12–0.15) crystals grown under different conditions. The results indicate that the full width at half maximum of the near-edge photoconductivity peak is sensitive to the state of native structural defects and can be used to assess the quality of Cd1 - xZnxTe crystals and their applicability in high-resolution gamma detectors.

Matrix differences and integral equations are introduced for the description of finite-valued non markovian random processes. In a special case we deduce an integral equation of a semi-Markov process. Necessary conditions are found for a semi-Markov process to be markovian. A generalized understanding of a semi-Markov random process is offered.

The paper presents a mathematical model of the process of motion of a charged liquid particle of variable mass in the interelectrode space. The Cauchy problem is formulated for the system of two ordinary nonlinear differential equations describing the radius of the spherical particle r(x) and its velocity v(x). An exact solution of the nonlinear system is obtained by introducing a physically acceptable simplification. Qualitative and quantitative analysis of the results is presented.

The stability of the zero solution of a first-order linear differential equation with a random right-hand side is investigated using moment equations. Transformations of moment equations are considered. Conditions for reducing the order of the moment equations are derived.

Systems of equations for first and second moments are investigated and transformed. Stability of solutions of a first-order linear differential equations is analyzed. Stability of solutions of the stochastic Mathieu equation is investigated and the boundaries of the instability region are determined.

Infrared detector development and characterization at NASA Langley Research Center will be reviewed. These detectors were intended for ground, airborne, and space borne remote sensing applications. Discussion will be focused on recently developed single-element infrared detector and future development of near-infrared focal plane arrays (FPA). The FPA will be applied to next generation space-based instruments. These activities are based on phototransistor and avalanche photodiode technologies, which offer high internal gain and relatively low noise-equivalent-power. These novel devices will improve the sensitivity of active remote sensing instruments while eliminating the need for a high power laser transmitter.