Using soybean-derived materials to rejuvenate reclaimed asphalt pavement (RAP) binders and mixtures

Over the past few years, the use of reclaimed asphalt pavement (RAP) has been growing consistently from 15% in 2009 to 20.3% in 2015. The desire to use higher amounts of RAP is inspired by the need to lower costs, conserve energy, and preserve the environment. Increasing asphalt prices, and limited supply of higher quality virgin aggregates, are strong motivations to use RAP as a replacement for the more expensive virgin asphalt and aggregates. The main obstacle from using higher amounts of RAP is the aged and deteriorated properties of the RAP binder. With aging, asphalt binders suffer from oxidation which results in the conversion of part of the maltenes fraction to asphaltenes. Asphaltenes are primarily responsible for increasing the asphalt stiffness. The use of rejuvenators help restore the balance between the asphaltenes and maltenes, by adding more maltenes and/or improving the dispersion of asphaltenes. Current rejuvenators that are available in the market are based on several materials including petroleum-based aromatic extracts, distilled tall oil, and other natural oils (i.e., organic oils). Bio-based rejuvenators have proven to be a better and safer alternative to petroleum-based rejuvenators containing aromatic compounds. This research introduces a soybean-derived rejuvenator which is used to enhance the low temperature and fatigue properties of asphalt binders. During the first phase of the research, the effect of the rejuvenator is assessed by blending it with a neat PG58-28 and a polymer modified PG64-28 binders. Dynamic Shear Rheometer (DSR) and Bending Beam Rheometer (BBR) tests are conducted to characterize the rheological properties of the rejuvenated binders. Temperature-frequency sweeps are conducted and complex shear modulus curves are constructed to compare between the control and the rejuvenated binders. Dynamic modulus specimens are made using the rejuvenated PG58-28 and PG64-28 binders. The impact of the rejuvenator on both the dynamic modulus and phase angles is studied using master curves. A comprehensive statistical analysis using split-plot repeated measures (SPRM) is conducted to reveal statistical differences between the performance of the rejuvenator in both types of binders. The preliminary results indicate that the soybean-derived rejuvenator was successful at lowering both the high and low critical temperatures of both types of binders. The statistical analysis revealed that the extent of modification brought about by the rejuvenator was dependent on the binder type. The results of the dynamic modulus testing showed a consistent reduction in the dynamic modulus values and an increase in the phase angles with the use of the rejuvenator. A Fourier-transform Infrared study (FTIR) performed on the rejuvenated binders indicated that their aging behavior was similar to that of the control binders, indicating that the rejuvenator did not adversely impact the durability of the binders. In the second phase of this research, a rejuvenated PG58-28 binders was blended with an extracted reclaimed asphalt pavement (RAP) binder. The fatigue behavior of the rejuvenated RAP binder is evaluated using linear amplitude sweep (LAS) testing. A significant increase in the fatigue life, particularly at low temperatures and increasing shear rate, is noted with the use of the rejuvenator. The rejuvenator was successful in lowering the performance grade of the stiff aged RAP binder to acceptable ranges. 100% RAP mixtures made and compacted into dynamic modulus and disk-compact tension (DCT) specimens were made using the neat PG58-28 and rejuvenated PG58-28 binders. The DCT specimens containing the rejuvenator showed higher fracture energy at a test temperature of -6oC which indicates better thermal cracking resistance. To assess the effect of blending efficiency, additional DCT specimens were prepared using extracted RAP binder blended with the rejuvenated PG58-28 binder. The RAP/rejuvenated PG58-28 blend was then remixed with the extracted RAP aggregate to simulate full blending. The DCT specimens prepared as such yielded even higher fracture energies indicating the significance of proper blending. The thermal stability of the rejuvenated RAP binder was verified using thermogravimetric analysis (TGA). The mass loss due to thermal decomposition of the rejuvenated RAP binder was similar to that of the control binder. A study of the evolved gases using FTIR showed that the rate of mass loss of the rejuvenator can be inferred by comparing the FTIR spectra at different times

Pharmacological evaluation of novel polysialyltransferase inhibitors as anti-metastatic agents and development of analytical methods for assessment of polysialylation inhibition. In vitro assessment of the effects of novel polysialyltransferase inhibitors on tumour cell function and development of quantitative HPLC-based methods for evaluation of novel polysialyltransferase inhibitors

Polysialic acid (polySia) is a carbohydrate polymer highly expressed during embryonic development but rarely expressed during postnatal development. Two polysialyltransferase (polyST) enzymes are responsible for the synthesis of polySia: ST8SiaII and ST8SiaIV. During oncogenesis polySia is re-expressed and it modulates cell-cell and cell-matrix adhesion, migration, invasion and metastasis. PolySia expression is strongly associated with poor clinical prognosis and correlates with aggressive and invasive disease in neuroblastoma and many other tumours. PolyST inhibition thus presents a novel, selective and largely unexplored therapeutic opportunity to reduce tumour dissemination. Progress towards development of polyST inhibitors has been limited by lack of an efficient technique for quantitative assessment of enzyme activity. We have validated a highly sensitive cell-based and cell-free high throughput HPLC-based inhibition assays. Using isogenic cell lines (C6-STX: polySia+/ST8SiaII+ and C6-WT: polySia-/ST8SiaII-) and naturally polySia expressing human neuroblastoma cells (SH-SY5Y), a set of ST8SiaII inhibitors designed and synthesised in house were evaluated for their ability to reduce polySia expression and to modulate cell migration in vitro. We have identified CMP-sialic acid precursors, including ICT-3176, which reduced polySia expression and tumour cell migration by up to 70%. These effects were only found in cell lines expressing ST8SiaII and polySia. Furthermore, we have investigated the possible additive anti-migratory effect of combining polyST inhibition with the inhibition of certain signalling pathways that have been previously suggested to be modulated by polySia expression. Out of these combinations it was found that combining ST8SiaII and C-MET/ALK inhibition had a synergistic effect on inhibiting cancer cell migration. Additionally, the effect of polySia expression on cancer cell behaviour under hypoxic conditions was examined, where it was found that polySia expression enhanced cell migration and survival and inhibits cell adhesion. In summary, polyST inhibitors which dramatically decrease cell migration in vitro through modulation of polySia assembly were identified, using optimised cell-free and cell-based assays. Initial investigations into the role of polySia in hypoxia were also accomplished. This work paves the way for development of a novel therapeutic for the treatment of neuroblastoma

Conductive paint-filled cement paste sensor for accelerated percolation

Cementitious-based strain sensors can be used as robust monitoring systems for civil engineering applications, such as road pavements and historic structures. To enable large-scale deployments, the fillers used in creating a conductive material must be inexpensive and easy to mix homogeneously. Carbon black (CB) particles constitute a promising filler due to their low cost and ease of dispersion. However, a relatively high quantity of these particles needs to be mixed with cement in order to reach the percolation threshold. Such level may influence the physical properties of the cementitious material itself, such as compressive and tensile strengths. In this paper, we investigate the possibility of utilizing a polymer to create conductive chains of CB more quickly than in a cementitious-only medium. This way, while the resulting material would have a higher conductivity, the percolation threshold would be reached with fewer CB particles. Building on the principle that the percolation threshold provides great sensing sensitivity, it would be possible to fabricate sensors using less conducting particles. We present results from a preliminary investigation comparing the utilization of a conductive paint fabricated from a poly-Styrene-co-Ethylene-co-Butylene-co-Styrene (SEBS) polymer matrix and CB, and CB-only as fillers to create cementitious sensors. Preliminary results show that the percolation threshold can be attained with significantly less CB using the SEBS+CB mix. Also, the study of the strain sensing properties indicates that the SEBS+CB sensor has a strain sensitivity comparable to the one of a CB-only cementitious sensor when comparing specimens fabricated at their respective percolation thresholds

Association between Genotype of the Serotonin Transporter-Linked Polymorphic Region of the Serotonin Transporter Gene and Age of Onset of Methamphetamine Use: a Preliminary Analysis

Early-onset methamphetamine use increases the lifetime prevalence of methamphetamine dependence. An earlier onset of methamphetamine use leads to greater damage to the terminal ends of serotonin neurons, more reduction in serotonin transporter (5-HTT) density, and an increased propensity toward further methamphetamine use. Because the 5-HTT-linked polymorphic region (5′-HTTLPR) within the promoter region of the 5-HTT gene leads to differential expression of the 5-HTT, we examined, for the first time, whether there is a differential association between the long (L) and short (S) alleles of the 5′-HTTLPR and the age of first methamphetamine use (AMU). The study included 120 methamphetamine-dependent adults of European descent. Diagnosis of methamphetamine dependence and AMU were collected using structured questionnaires, and the 5′-HTTLPR genotypes were determined using the polymerase chain reaction–restriction fragment length polymorphism method. Statistical analysis with the general linear model detected a significant interactive effect of 5′-HTTLPR genotypes (SS vs. L-carriers) and gender, associated with AMU (F = 3.99; p = 0.048). Further analysis of 5′-HTTLPR effects on AMU in males and females separately showed that the SS genotype compared with L-carriers had about two times greater risk of an earlier onset of methamphetamine use in men (hazard ratio = 1.839; 95% confidence interval = 1.042–3.246; p = 0.036) but not in women. Together, our findings in this preliminary study suggest a greater risk for earlier onset methamphetamine use associated with the SS genotype of the 5′-HTTLPR among methamphetamine-dependent Caucasian males

Tryptophan for the sleeping disorder and mental symptom of new-type drug dependence: A randomized, double-blind, placebo-controlled trial

New-type drugs are popular with adolescents and could lead to psychiatry disorders, but no medications have been proven to be effective for these disorders of new-type drug dependence. We aimed to evaluate the efficacy of tryptophan on sleeping disorders and mental symptoms in detoxified individuals with new-type drug dependence. This randomized, placebo controlled trial included 80 detoxified individuals with new-type drug dependence, recruited successively from a Compulsory Residential Drug Abstinence Institution in Wuhan, China, from April 2012 to November 2012. Eligible participants were randomly allocated to be treated with tryptophan (1000mg/day, n=40) or placebo (n=40) for two weeks. The sleeping and mental symptoms were assessed using Athens Insomnia Scale (AIS) and Symptom Check-List-90 (SCL-90) at baseline and two weeks. Results were analyzed according to the “intention-to-treat” approach. Forty-five participants completed the two-week study, 24 in the tryptophan group and 21 in the placebo group. There were no statistically significant differences in baseline characteristics between groups and the treatment adherence was similar between groups. The reduction in the Athens Insomnia Scale (AIS) score in the tryptophan group was significantly greater than that in the placebo group (P=0.017). However, no significant differences were found in Symptom Check-List-90 (SCL-90) scores (either by individual dimension or the overall score) between groups (all P>0.05). The frequency of adverse events were similar and no serious adverse events were reported during the study. Tryptophan was unlikely to be effective for mental symptoms, but could alleviate sleep disorders in short term among detoxified individuals with new-type drug dependence. Future large scale trials are required to confirm findings from this study

An optimised assay for quantitative, high-throughput analysis of polysialyltransferase activity

YesThe polysialyltransferases are biologically important glycosyltransferase enzymes responsible for the biosynthesis of polysialic acid, a carbohydrate polymer that plays a critical role in the progression of several diseases, notably cancer. Having improved the chemical synthesis and purification of the fluorescently-labelled DMB-DP3 acceptor, we report optimisation and validation of a highly sensitive cell-free high-throughput HPLC-based assay for assessment of human polysialyltransferase activity

Brain structural changes and neuropsychological impairments in male polydipsic schizophrenia

BACKGROUND: Polydipsia frequently occurs in schizophrenia patients. The excessive water loading in polydipsia occasionally induces a hyponatremic state and leads to water intoxication. Whether polydipsia in schizophrenic patients correlates with neuropsychological impairments or structural brain changes is not clear and remains controversial. METHODS: Eight polydipsic schizophrenia patients, eight nonpolydipsic schizophrenia patients, and eight healthy controls were recruited. All subjects underwent magnetic resonance imaging (MRI) and neuropsychological testing. Structural abnormalities were analyzed using a voxel-based morphometry (VBM) approach, and patients’ neuropsychological function was assessed using the Brief Assessment of Cognition in Schizophrenia, Japanese version (BACS-J). RESULTS: No significant differences were found between the two patient groups with respect to the clinical characteristics. Compared with healthy controls, polydipsic patients showed widespread brain volume reduction and neuropsychological impairment. Furthermore, the left insula was significantly reduced in polydipsic patients compared with nonpolydipsic patients. These nonpolydipsic patients performed intermediate to the other two groups in the neuropsychological function test. CONCLUSIONS: It is possible that polydipsia or the secondary hyponatremia might induce left insula volume reduction. Furthermore, this structural brain change may indirectly induce more severe neuropsychological impairments in polydipsic patients. Thus, we suggest that insula abnormalities might contribute to the pathophysiology of polydipsic patients

A Phase 1 Trial of pharmacologic interactions between transdermal selegiline and a 4-hour cocaine infusion

BackgroundThe selective MAO-B inhibitor selegiline has been evaluated in clinical trials as a potential medication for the treatment of cocaine dependence. This study evaluated the safety of and pharmacologic interactions between 7 days of transdermal selegiline dosed with patches (Selegiline Transdermal System, STS) that deliver 6 mg/24 hours and 2.5 mg/kg of cocaine administered over 4 hours.MethodsTwelve nondependent cocaine-experienced subjects received deuterium-labeled cocaine-d5 intravenously (IV) 0.5 mg/kg over 10 minutes followed by 2 mg/kg over 4 hours before and after one week of transdermal selegiline 6 mg/24 hours. Plasma and urine were collected for analysis of selegiline, cocaine, catecholamine and metabolite concentrations. Pharmacodynamic measures were obtained.ResultsSelegiline did not change cocaine pharmacokinetic parameters. Selegiline administration increased phenylethylamine (PEA) urinary excretion and decreased urinary MHPG-sulfate concentration after cocaine when compared to cocaine alone. No serious adverse effects occurred with the combination of selegiline and cocaine, and cocaine-induced physiological effects were unchanged after selegiline. Only 1 peak subjective cocaine effects rating changed, and only a few subjective ratings decreased across time after selegiline.ConclusionNo pharmacological interaction occurred between selegiline and a substantial dose of intravenous cocaine, suggesting the combination will be safe in pharmacotherapy trials. Selegiline produced few changes in subjective response to the cocaine challenge perhaps because of some psychoactive neurotransmitters changing in opposite directions