Interfacial chemical oxidative synthesis of multifunctional polyfluoranthene.

A novel polyfluoranthene (PFA) exhibiting strong visual fluorescence emission, a highly amplified quenching effect, and widely controllable electrical conductivity is synthesized by the direct cationic oxidative polymerization of fluoranthene in a dynamic interface between n-hexane and nitromethane containing fluoranthene and FeCl3, respectively. A full characterization of the molecular structure signifies that the PFAs have a degree of polymerization from 22-50 depending on the polymerization conditions. A polymerization mechanism at the interface of the hexane/nitromethane biphasic system is proposed. The conductivity of the PFA is tunable from 6.4 × 10-6 to 0.074 S cm-1 by doping with HCl or iodine. The conductivity can be significantly enhanced to 150 S cm-1 by heat treatment at 1100 °C in argon. A PFA-based chemosensor shows a highly selective sensitivity for Fe3+ detection which is unaffected by other common metal ions. The detection of Fe3+ likely involves the synergistic effect of well-distributed π-conjugated electrons throughout the PFA helical chains that function as both the fluorophore and the receptor units

Facile Synthesis and Versatilities of Polyanthraquinoylamine Nanofibril Bundles with Self Stability and High Carbon Yield

A facile synthesis for nanosized conducting polymers with inherent self-stability and multi-functionalities is a main challenge. Here we simply synthesize intrinsically self-stabilized nanofibril bundles of poly(1-anthraquinoylamine) (PAQ) by a template-free method. The critical polymerization parameters were studied to significantly optimize the synthesis, size, properties, and functionalities of the resulted fine nanofibrils with a diameter of ca. 30 nm and length of ~6 μm. The PAQ obtained with ammonium persulfate possesses higher polymerization yield, purer composition, higher conductivity, better melting behaviour, higher thermostability, lower burning enthalpy, and slower degradation than that with other oxidants. Furthermore, the polymer nanofibrils exhibit high self-stability, powerful redispersibility, high purity, and clean surface because of a complete avoidance of the contamination from external stabilizer. The PAQ exhibits widely controllable conductivity moving across ten orders of magnitudes from 10^-9^ to 50 S/cm, photoluminescence, lead-ion adsorbability, very high thermostability in air and extremely high char yield in nitrogen at 1000˚C. These materials would be useful as advanced materials including photoluminescent materials, highly cost-effective carbon precursors, sorbents of toxic metal ions, and cost-efficient conductive nanocomposite with low percolation threshold

Supercritical Ethanol Technology For The Production Of Biodiesel From Palm Oil And Jatropha Oil

Minyak kelapa sawit; yang terdapat di seluruh Malaysia, merupakan sumber minyak yang berpotensi untuk penghasilan biodiesel di kawasan ini. Sementara itu, minyak jarak, juga dipercayai adalah sumber minyak yang berpotensi disebabkan kesesuaiannya untuk keadaan cuaca di Malaysia. Oleh itu, penghasilan biodiesel daripada minyak kelapa sawit and minyak jarak telah dikaji dalam projek ini dengan menggunakan teknologi genting lampau etanol tanpa penggunaan mangkin. Pada mulanya, pencirian minyak kelapa sawit dan minyak jarak telah dikaji untuk ciri-ciri fizikal, kimia dan therma. Palm oil; which is available throughout Malaysia is a potential oil feedstock for the production of biodiesel in this region. Jatropha (Jatropha curcas) oil, on the other hand, is believed to be another potential oil source for biodiesel production due to its non-edible nature and high suitability to tropical climate in Malaysia. Therefore, production of biodiesel from palm oil and jatropha oil was studied in the present research work via non-catalytic transesterification in supercritical ethanol technology. Initially, palm oil and jatropha oil were characterized for their physical, chemical and thermal properties

Effect of Astragalus membranaceus (Fisch) Bunge extract on streptozocin-induced diabetic in rats

Purpose: To investigate the effect of Astragalus membranaceus (Fisch.) Bunge. extract (AMBE) on streptozotocin-induced diabetic rats.Methods: The aqueous extract of AMB was obtained by steeping the dried  Astragalus membranaceus (Fisch.) Bunge. in water at 60 oC three times, each for 1 h, before first drying in an oven at 100 oC and then freeze-drying the last extract thus obtained. Diabete model rats was induced by a single intraperitoneal injection of a freshly prepared solution of streptozotocin (50 mg/kg). The rats were randomly divided into 6 groups of ten rats each: negative control group, normal control group, reference group (glibenclamide1 mg/kgbody weight) as well as AMB extract groups, namely, 40, 80 and 160 mg/kg body weight. Antihyperglycemic effect was measured by blood glucose and plasma insulin levels. Oxidative stress was evaluated in liver and kidney by antioxidant markers, viz, lipidperoxidation (LPO), superoxide  dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx) and catalase (CAT), while blood serum levels of creatinine and urea were also determined in both diabetic control and treated rats.Results: Compared with diabetic rats, oral administration of AMBE at a  concentration of 160 mg/kg daily for 30 days showed a significant decrease in fasting blood glucose (109.438 ± 3.52, p < 0.05) and increased insulin level (13.96 ± 0.74, p < 0.05). Furthermore, it significantly reduced biochemical parameters (serum creatinine, 0.86 ± 0.29, p < 0.05) and serum urea (45.14 ± 1.79, p < 0.05). The treatment also resulted in significant increase in GSH (49.21 ± 2.59, p < 0.05), GPx (11.96 ± 1.16, p < 0.05), SOD (14.13 ± 0.49, p < 0.05), CAT (83.25 ± 3.14, p < 0.05) level in the liver and kidney of diabetic rats.Conclusion: The results suggest that AMBE may effectively normalize impaired  antioxidant status in streptozotocin-induced diabetes in a dose-dependent manner. AMBE has a protective effect against lipid peroxidation by scavenging free radicals and is thus capable of reducing the risk of diabetic complications.Keywords: Astragalus membranaceus, Diabetic, Antihyperglycemic, Antioxidant Oxidative stress, Fasting blood glucos

Assessing the effects of time-dependent restrictions and control actions to flatten the curve of COVID-19 in Kazakhstan

This paper presents the assessment of time-dependent national-level restrictions and control actions and their effects in fighting the COVID-19 pandemic. By analysing the transmission dynamics during the first wave of COVID-19 in the country, the effectiveness of the various levels of control actions taken to flatten the curve can be better quantified and understood. This in turn can help the relevant authorities to better plan for and control the subsequent waves of the pandemic. To achieve this, a deterministic population model for the pandemic is firstly developed to take into consideration the time-dependent characteristics of the model parameters, especially on the ever-evolving value of the reproduction number, which is one of the critical measures used to describe the transmission dynamics of this pandemic. The reproduction number alongside other key parameters of the model can then be estimated by fitting the model to real-world data using numerical optimisation techniques or by inducing ad-hoc control actions as recorded in the news platforms. In this paper, the model is verified using a case study based on the data from the first wave of COVID-19 in the Republic of Kazakhstan. The model is fitted to provide estimates for two settings in simulations; time-invariant and time-varying (with bounded constraints) parameters. Finally, some forecasts are made using four scenarios with time-dependent control measures so as to determine which would reflect on the actual situations better.Comment: 35 pages, 7 figures, To appear in Peer

Mtmr8 is essential for vasculature development in zebrafish embryos

<p>Abstract</p> <p>Background</p> <p>Embryonic morphogenesis of vascular and muscular systems is tightly coordinated, and a functional cooperation of Mtmr8 with PI3K in actin filament modeling and muscle development has been revealed in zebrafish. Here, we attempt to explore the function of Mtmr8 in vasculature development parallel to its function in muscle development.</p> <p>Results</p> <p>During early stage of somitogenesis, <it>mtmr8 </it>expression was detected in both somitic mesodem and ventral mesoderm. Knockdown of <it>mtmr8 </it>by morpholino impairs arterial endothelial marker expression, and results in endothelial cell reduction and vasculogenesis defects, such as retardation in intersegmental vessel development and interruption of trunk dorsal aorta. Moreover, <it>mtmr8 </it>morphants show loss of arterial endothelial cell identity in dorsal aorta, which is effectively rescued by low concentration of PI3K inhibitor, and by over-expression of <it>dnPKA </it>mRNA or <it>vegf </it>mRNA. Interestingly, <it>mtmr8 </it>expression is up-regulated when zebrafish embryos are treated with specific inhibitor of Hedgehog pathway that abolishes arterial marker expression.</p> <p>Conclusion</p> <p>These data indicate that Mtmr8 is essential for vasculature development in zebrafish embryos, and may play a role in arterial specification through repressing PI3K activity. It is suggested that Mtmr8 should represent a novel element of the Hedgehog/PI3K/VEGF signaling cascade that controls arterial specification.</p

Could protein tertiary structure influence mammary transgene expression more than tissue specific codon usage?

Animal mammary glands have been successfully employed to produce therapeutic recombinant human proteins. However, considerable variation in animal mammary transgene expression efficiency has been reported. We now consider whether aspects of codon usage and/or protein tertiary structure underlie this variation in mammary transgene expression