Non-isothermal degradation kinetics of poly (2,2′-dihydroxybiphenyl)

Catalytic oxidative polymerization of 2,2′-dihydroxybiphenyl (DHBP) was performed by using Schiff base polymer-Cu (II) complex and hydrogen peroxide as catalyst and oxidant, respectively. According to size exclusion chromatography (SEC) analysis, the number-average molecular weight (M _n), weight-average molecular weight (M _w) and polydispersity index (PDI) values of poly (2,2′-dihydroxybiphenyl) (PDHBP) were found to be 37,500, 90,000 g mol⁻¹ and 2.4, respectively. The thermal degradation kinetics was investigated by thermogravimetric analysis in dynamic nitrogen atmosphere at four different heating rates: 5, 10, 15 and 20 °C min⁻¹. The derivative thermogravimetry curves of PDHBP showed that its thermal degradation process had one weight-loss step. The apparent activation energies of thermal decomposition for PDHBP as determined by Tang, Flynn–Wall–Ozawa (FWO), Kissenger–Akahira–Sunose (KAS), Coats–Redfern (CR) and Invariant kinetic parameter (IKP) methods were 109.1, 109.0, 110.0, 108.4 and 109.8 kJ mol⁻¹, respectively. The mechanism function and pre-exponential factor were determined by master plots and Criado–Malek–Ortega method. The most likely decomposition process was a D _n Deceleration type in terms of the CR, master plots and Criado–Malek–Ortega results.     

Quantitative T 2 * assessment of acute and chronic myocardial ischemia/reperfusion injury in mice

Object

Imaging of myocardial infarct composition is essential to assess efficacy of emerging therapeutics. T ₂ ^* mapping has the potential to image myocardial hemorrhage and fibrosis by virtue of its short T ₂ ^* . We aimed to quantify T ₂ ^* in acute and chronic myocardial ischemia/reperfusion (I/R) injury in mice.

Materials and methods

I/R-injury was induced in C57BL/6 mice (n?=?9). Sham-operated mice (n?=?8) served as controls. MRI was performed at baseline, and 1, 7 and 28?days after surgery. MRI at 9.4?T consisted of Cine, T ₂ ^* mapping and late-gadolinium-enhancement (LGE). Mice (n?=?6) were histologically assessed for hemorrhage and collagen in the fibrotic scar.

Results

Baseline T ₂ ^* values were 17.1?±?2.0?ms. At day 1, LGE displayed a homogeneous infarct enhancement. T ₂ ^* in infarct (12.0?±?1.1?ms) and remote myocardium (13.9?±?0.8?ms) was lower than at baseline. On days 7 and 28, LGE was heterogeneous. T ₂ ^* in the infarct decreased to 7.9?±?0.7 and 6.4?±?0.7?ms, whereas T ₂ ^* values in the remote myocardium were 14.2?±?1.1 and 15.6?±?1.0?ms. Histology revealed deposition of iron and collagen in parallel with decreased T ₂ ^* .

Conclusion

T ₂ ^* values are dynamic during infarct development and decrease significantly during scar maturation. In the acute phase, T ₂ ^* values in infarcted myocardium differ significantly from those in the chronic phase. T ₂ ^* mapping was able to confirm the presence of a chronic infarction in cases where LGE was inconclusive. Hence, T ₂ ^* may be used to discriminate between acute and chronic infarctions.     

Control of Aspergillus flavus with essential oil and methanol extract of Satureja hortensis

The essential oil and methanol extract of Satureja hortensis were tested for antifungal activity against Aspergillus flavus in vitro on Petri plates and liquid culture, and under storage conditions. The oil showed strong antifungal activity based on the inhibition zone and minimal inhibitory concentration values against the pathogen on Petri plates assays. The very low concentrations of them also reduced wet and dry mycelium weight of pathogen fungus in liquid culture. When the oils at 25, 12.5 and 6.25 microl/mL concentrations were applied to lemon fruits before seven days of pathogen inoculation on storage conditions, the decay on fruits caused by the pathogen could be prevented completely. The results in this study showed that the essential oil of S. hortensis had strong antifungal activity against pathogen fungi tested. So, the essential oil of S. hortensis could be used for management of this pathogen as a potential source of sustainable eco-friendly botanical fungicides.     

Quantitation of heterocyclic aromatic amines in ready to eat meatballs by ultra fast liquid chromatography

Heterocyclic aromatic amines (HCAs) in meatballs ready to eat and sold in restaurants in Turkey were determined. A solid phase extraction method was used to isolate HCAs from meatballs. Various HCAs analysed by ultra fast liquid chromatography (UFLC) were varying levels of 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) (up to 1.59 ng/g), 2-amino-3-methylimidazo[4,5-f]quinoxaline (IQx) (up to 3.81 ng/g), 2-amino-3,4-dimethylimidazo[4,5-f]quinoline (MeIQ) (up to 0.66 ng/g), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) (not detected or not quantified), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (not detected or not quantified), 2-amino-3,7,8-trimethylimidazo[4,5-f]quinoxaline (7,8-DiMeIQx) (up to 0.43 ng/g), 2-amino-1-methyl-6-phenylimidazo[4,5-b] pyridine (PhIP) (up to 1.93 ng/g), 2-amino-9H-pyrido[2,3-b]indole (AαC) (up to 0.35 ng/g), and 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeAαC) (up to 0.43 ng/g) in cooked meatballs which are consumed in Turkey. Overall average of total HCA amount was 5.54 ng/g. The present study is to prove that HCAs can be isolated in a very short time (5 min) by using UFLC.     

Split-attention effects in multimedia learning environments: eye-tracking and EEG analysis

Multimedia Tools and Applications - This study aimed to evaluate the split-attention effect in multimedia learning environments via objective measurements as EEG and eye-tracking. Two different...     

Energy-efficient and fault-tolerant drone-BS placement in heterogeneous wireless sensor networks

Wireless Networks - This paper introduces a distributed and energy-aware algorithm, called Minimum Drone Placement (MDP) algorithm, to determine the minimum number of base stations mounted on...     

Correction to: Two New Co(II) Complexes of Picolinate: Synthesis,Crystal Structure,Spectral Characterization, α-Glucosidase İnhibition and TD/DFT Study

Journal of Inorganic and Organometallic Polymers and Materials -     

A haar wavelet approximation for two-dimensional time fractional reaction–subdiffusion equation

Engineering with Computers - In this study, we established a wavelet method, based on Haar wavelets and finite difference scheme for two-dimensional time fractional reaction–subdiffusion...     

Combining Electricity and Fuel Supply: Operational Strategies for Biogas Plants

The operational consequences resulting from the combination of a flexibly operated combined heat and power unit (CHP) and an off‐grid biomethane filling station at one biogas plant were investigated. Four different operating scenarios were compared to evaluate the storage capacity needed to balance biogas demand fluctuations and biogas production. The scenario in which fuel production was given priority and electricity was produced within the remaining hours proved to cause the lowest additional costs since it does not require additional installation of biogas storage capacity and causes minor opportunity cost in electricity marketing. Giving fuel demand the priority reduces the necessary biogas storage capacity by 75 % compared to parallel optimization of the electricity and fuel demands.