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Densities, ultrasonic speeds, refractive indices, and COSMO analysis for binary mixtures of dichloromethane with acetone and dimethylsulfoxide at T = (298.15, 303.15, and 308.15) K
No full textExperimental densities (ρ), ultrasonic speeds (u), and refractive indices (nD) of binary mixtures of dichloromethane (DCM) with acetone (ACT) and dimethylsulfoxide (DMSO) were measured over the whole composition range at T = 298.15, 303.15, and 308.15 K. From the experimental data, excess molar volume (VE), deviations in isentropic compressibility (Δks), deviations in intermolecular free length (ΔLf), deviations in refractive index (ΔnD), and deviations in ultrasonic speed (Δu) were calculated. Moreover, the Benson–Kiyohara theory was applied to the binary mixtures to obtain the theoretical Δks values. The COSMO calculations depending on density functional theory were utilized to estimate the σ-profiles for the DCM, ACT, and DMSO. The interpreted σ-profile trends were found supportive with the experimental findings. Applicability of different empirical and semi-empirical relations of refractive index data were tested against the measured results, and good agreement has been obtained. The possible results of intermolecular molecular interactions among mixture components were interpreted
Spatial and seasonal use of habitat by birds in northern Nigeria
No full textCapsule: Although woodland habitat supports higher avian species diversity and abundance, shrubland may be more important for migratory species. Aims: To investigate the use of habitat, site and season by bird species according to feeding guild, residence status and population trend in Dutse, Northern Nigeria. Methods: A point transect was used to count and identify birds between 0630 and 1100 hours from August 2015 to February 2016 across habitats, sites and seasons in Dutse. Results: Frugivore abundance was significantly higher in woodland habitat. The woodland and shrubland habitats had a higher proportion of resident and migratory species, respectively. Birds with stable population trends were more abundant in woodland, whereas the abundance of birds with decreasing trends were generally similar across most sites. Most of the birds with decreasing trends were migratory species. The dry season had a higher abundance and diversity of birds across different feeding guilds, residence status and population trend status than the wet season. Conclusion: Both woodland and shrubland in Dutse were important bird habitats, but migrant species preferentially used shrubland. The shrubland habitat and the dry season should be prioritized for conservation consideration, especially for migrant birds in Dutse
All-fibre Q-switching YDFL operation with bismuth-doped fibre as saturable absorber
No full textWe demonstrate the generation of a passively Q-switched ytterbium-doped fibre laser (YDFL) using a bismuth-doped fibre (BDF) as a solid-state fibre saturable absorber (FSA) in a ring cavity. The BDF used has a wide and low absorption band of 5 dB/m at the 1.0 μm region due to the ion transition of 3P0 → 3P1 that occurs around the region. When introduced into a YDFL laser cavity, a stable Q-switched pulse operation was observed and the pulse repetition rate was proportional to the input pump power. It was limited to 72.99 kHz by the maximum power that the laser diode could supply. Meanwhile, the pulse width decreased from 12.22 to 4.85 μs as the pump power was increased from 215.6 to 475.6 mW. The finding suggests that BDF could be used as a potential SA for the development of robust, compact, efficient and low cost Q-switched fibre lasers operating at 1 micron region
An inhibitory action of chitosan nanoparticles against pathogenic bacteria and fungi and their potential applications as biocompatible antioxidants
No full textChitosan is the second most abundant polymer obtained from the byproduct of seafood. Chitosan and its derivatives and chitosan loaded drugs are the recent area of interest against microbial pathogenesis. The cationic chitosan nanoparticles (ChNPs) interact with the anionic surfaces of the microbial cell membrane, which promotes antimicrobial activity. Although, ChNPs are potential against pathogenic microbes, selection of adaptable, suitable and cost effective synthesis method is much important. In the present study, ChNPs were synthesized adopting ionic gelation using sodium tripolyphosphate as a cross linking agent and characterized by FTIR, DLS, SEM and TEM analysis. ChNPs were investigated for antimicrobial activity against bacterial (Escherichia coli and Staphylococcus aureus) and fungal (Candida albicans) pathogens. ChNPs showed bactericidal activity at the lower minimum inhibitory concentration of about 40–80 μg mL−1. Interestingly, ChNPs exhibits biocompatible antioxidant property by inhibiting DPPH free radicals at 76% and also proven to be a potential candidate against the microbial pathogenesis with an inevitable applications in biomedicine
Acute effects of methadone on EEG power spectrum and event-related potentials among heroin dependents
No full textMethadone as the most prevalent opioid substitution medication has been shown to influence the neurophysiological functions among heroin addicts. However, there is no firm conclusion on acute neuroelectrophysiological changes among methadone-treated subjects as well as the effectiveness of methadone in restoring brain electrical abnormalities among heroin addicts. This study aims to investigate the acute and short-term effects of methadone administration on the brain’s electrophysiological properties before and after daily methadone intake over 10 weeks of treatment among heroin addicts. EEG spectral analysis and single-trial event-related potential (ERP) measurements were used to investigate possible alterations in the brain’s electrical activities, as well as the cognitive attributes associated with MMN and P3. The results confirmed abnormal brain activities predominantly in the beta band and diminished information processing ability including lower amplitude and prolonged latency of cognitive responses among heroin addicts compared to healthy controls. In addition, the alteration of EEG activities in the frontal and central regions was found to be associated with the withdrawal symptoms of drug users. Certain brain regions were found to be influenced significantly by methadone intake; acute effects of methadone induction appeared to be associative to its dosage. The findings suggest that methadone administration affects cognitive performance and activates the cortical neuronal networks, resulting in cognitive responses enhancement which may be influential in reorganizing cognitive dysfunctions among heroin addicts. This study also supports the notion that the brain’s oscillation powers and ERPs can be utilized as neurophysiological indices for assessing the addiction treatment traits
New Silver Complexes with Mixed Thiazolidine and Phosphine Ligands as Highly Potent Antimalarial and Anticancer Agents
No full textFive silver(I) complexes containing a mixed ligand system of phosphine and thiazolidine were successfully synthesized. The structural information of the complexes was assembled using various spectroscopic techniques such as CHN elemental analysis, Fourier transformed infrared (FTIR), 1 H, 13 C, and 31 P{ 1 H} NMR spectroscopy, and thermogravimetric analysis (TGA). A bidentate phosphine ligand acted as a chelating agent which bond to the silver in 1: 2 molar ratios. Meanwhile, thiazolidine was attached to the silver in a 1: 1 molar ratio. The antiplasmodial properties of all synthesized complexes were investigated on chloroquine-resistant P. falciparum parasite via HRP2 assays and cytotoxicity tests on Vero cells. Of all the synthesized complexes, complex 2 showed the highest SI value (more than 12.4) followed by complex 5 (6.6). The potent properties of compounds 2 and 5 were also noted in the in vitro antiproliferative assays involving MDA-MB-231 and MCF-7 breast cancer cell lines as well as HT-29 colon cancer cell line. Complex 2 was selective for MDA-MB-231 cells (GI 50 = 1.9 ± 0.3 μM), while complex 5 acted predominantly on breast carcinoma cells (GI 50 MDA-MB-231 = 4.7 ± 1.1 μM; MCF-7 = 2.9 ± 0.9 μM) instead of colon carcinoma (HT-29) cells (GI 50 = 15.1 ± 1.9 μM)
Dosage-dependent reduction of macular pigment optical density in female breast cancer patients receiving tamoxifen adjuvant therapy
No full textIt is now increasingly common for breast cancer patients to receive adjuvant tamoxifen therapy for a period of up to 10 years. As survival rate increases, managing tamoxifen ocular toxicities is important for patients' quality of life. Macular pigments in photoreceptor cells protect against free radical damage, which can cause macular degeneration. By reducing macular pigment concentration, tamoxifen may increase the risk of macular degeneration. Here, we compared macular pigment optical density (MPOD) and central macular thickness between breast cancer patients on tamoxifen adjuvant therapy (n = 70), and a control group (n = 72). Multiple regression analysis indicated that MPOD decreases with increasing tamoxifen dosage, up to a threshold of about 20 g, after which MPOD plateaus out. Mean MPOD in the treatment group (mean = 0.40) was significantly lower (p-value = 0.02) compared to the control group (mean = 0.47) for the left eye, and for the right eye (treatment mean = 0.39; control mean = 0.48; p-value = 0.009). No significant difference in mean central macular thickness was found between the treatment and the control group (p-values > 0.4). In the control group, MPOD and central macular thickness showed significant correlation (r∼0.30; p-values < 0.01) for both eyes. However, in the treatment group, loss of significant correlation was observed in the left eye (r = 0.21; p-value = 0.08). The present results show that MPOD decreases non-linearly as a function of tamoxifen dosage, and highlight the potential of tamoxifen to reduce macular pigment concentration through an unknown mechanism that does not depend on macular thinning solely
Phylogeny and species delineation in the marine diatom Pseudo-nitzschia (Bacillariophyta) using cox1 , LSU, and ITS2 rRNA genes: A perspective in character evolution
No full textAnalyses of the mitochondrial cox1, the nuclear-encoded large subunit (LSU), and the internal transcribed spacer 2 (ITS2) RNA coding region of Pseudo-nitzschia revealed that the P. pseudodelicatissima complex can be phylogenetically grouped into three distinct clades (Groups I–III), while the P. delicatissima complex forms another distinct clade (Group IV) in both the LSU and ITS2 phylogenetic trees. It was elucidated that comprehensive taxon sampling (sampling of sequences), selection of appropriate target genes and outgroup, and alignment strategies influenced the phylogenetic accuracy. Based on the genetic divergence, ITS2 resulted in the most resolved trees, followed by cox1 and LSU. The morphological characters available for Pseudo-nitzschia, although limited in number, were overall in agreement with the phylogenies when mapped onto the ITS2 tree. Information on the presence/absence of a central nodule, number of rows of poroids in each stria, and of sectors dividing the poroids mapped onto the ITS2 tree revealed the evolution of the recently diverged species. The morphologically based species complexes showed evolutionary relevance in agreement with molecular phylogeny inferred from ITS2 sequence–structure data. The data set of the hypervariable region of ITS2 improved the phylogenetic inference compared to the cox1 and LSU data sets. The taxonomic status of P. cuspidata and P. pseudodelicatissima requires further elucidation
New identification of the moray eel Gymnothorax minor (Temminck & Schlegel, 1846) in China (Anguilliformes, Muraenidae)
No full textA new identification of Gymnothorax minor (Temminck & Schlegel, 1846) is documented based on morphological characteristics and DNA barcoding. Sixty-one individuals of G. minor were collected from the East China Sea and the South China Sea. This species was previously reported as Gymnothorax reticularis Bloch, 1795 in China because of the similarity in external shape and color. Gymnothorax minor can be easily distinguished from G. reticularis by its color pattern of 18–20 irregular dark brown vertical bars and the body having scattered small brown spots. Additionally, the teeth are uniserial on both jaws, and the vertebrae number 137–139. By combining congener sequences of the cytochrome oxidase I (COI) gene from GenBank, two groups were detected among all the COI sequences of the currently named G. minor, which further indicated that two valid species were present based on genetic distance. A divergence also occurred on the number of vertebrae between the northern and southern populations. The phylogenetic and morphological analysis strongly supports that the northern and southern populations of G. minor are two different species. Furthermore, the distribution area of the northern G. minor has expanded southward to 5°15'N in the South China Sea. More specimens of G. minor and G. reticularis are crucial in order to define their geographical distribution boundaries and provide the correct DNA barcoding
Optimizing first line 7‐day standard triple therapy for Helicobacter pylori eradication: Prolonging treatment or adding bismuth: which is better?
No full textObjective: The 7-day standard triple therapy (STT) gives unacceptablly low eradication rates of Helicobacter pylori (H. pylori). We aimed to examine whether extending STT from 7 days to 14 days or adding a bismuth compound to a 7-day STT would result in better eradication rates. Methods: H. pylori-positive patients were assigned to Group A (7-day STT; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily, for 7 days), Group B (7-day STT with bismuth; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, clarithromycin 500 mg twice daily and bismuth subcitrate 240 mg twice daily, for 7 days) and Group C (14-day STT; rabeprazole 20 mg twice daily, amoxicillin 1 g twice daily, and clarithromycin 500 mg twice daily for 14 days). Eradication was tested using 13 C-UBT at least 4 weeks after the completion of therapy. Results: A total of 364 patients were recruited. In the intention-to-treat analysis, eradication rates were 79.3% (96/121; 95% confidence interval [CI] 71.3–85.6%) for 7-day STT, 81.7% (98/120; 95% CI 73.8–87.6%) for 7-day STT with bismuth, and 88.6% (109/123; 95% CI 81.8–93.1%) for 14-day STT, respectively. Statistical significance was achieved between the 7-day and the 14-day STT treatment (P = 0.048). Conclusions: Adding bismuth to the 7-day STT did not result in an increase in the eradication rate. Extending the STT to 14 days, however, achieved a significantly higher eradication rate. Nevertheless, this did not achieve the targeted 90% eradication rate on intention-to-treat analysis