Novel Silicon Phthalocyanines Bearing Triethylene Glycol Groups: Photophysical and Photochemical Properties as well as pH-Induced Spectral Behaviour

Herein, novel silicon (IV) phthalocyanines peripherally substituted by triethylene glycol groups and bearing axial hydroxyl groups were synthesized and fully characterized by using different analyses techniques. The photophysical and photochemical properties of octa (2a) and tetra (2b) derivatives were investigated in DMF and DMSO. The effect of octa or tetra substitution on fluorescence quantum yield, singlet oxygen generation and photodegradation were examined, and the differences were evaluated regarding their potential efficiency in photodynamic therapy (PDT). Their pH-responses were investigated to determine the influence of protonation of azomethine nitrogen atoms on singlet oxygen generation efficiencies. Dramatic optical changes were observed by protonation of azomethine bridges of 2a and 2b. They exhibited signal decrease from pH 4.0 to 1.0 for 2a (pKa = 2.6) and pH 3.0 to 1.0 for 2b (pKa = 1.8). Besides, the compounds exhibited no aggregation tendency, moderate fluorescence quantum yield, solubility in common organic solvents, high singlet oxygen quantum yield and high photostability in DMF and in DMSO, these favorable properties making them good candidates as photosensitizer for PDT.     

Oscillation criteria for nth-order forced functional differential equations

In this paper, by using the method of general means, some new oscillation criteria for forced functional differential equations of the form

     

Synthesis and Antinociceptive Effect of Some Thiazole-Piperazine Derivatives: Involvement of Opioidergic System in the Activity

In this study, we aimed to design and synthesize novel molecules carrying both the thiazole and piperazine rings in their structures and to investigate their antinociceptive activity. Targeted compounds were obtained by reacting thiosemicarbazide derivative and appropriate 2-bromoacetophenone in ethanol. The structures of the obtained compounds were determined using data from various spectroscopic methods (IR, ¹H-NMR, ¹³C-NMR, and LCMSMS). Experimental data from in vivo tests showed that test compounds 3a–3c, 3f, and 3g (50 mg/kg) significantly prolonged reaction times of animals in tail-clip and hot-plate tests compared to the controls, indicating that these compounds possess centrally mediated antinociceptive activities. Furthermore, these compounds reduced the number of writhing behaviors in the acetic acid-induced writhing tests, showing that the compounds also possess peripheral antinociceptive activity. In the mechanistic studies, naloxone pre-treatments abolished the antinociceptive activities of compounds 3a–3c, 3f, and 3g, indicating that opioidergic mechanisms were involved in their antinociceptive effects. Molecular docking studies demonstrating significant interactions between the active compounds and µ- and δ-opioid receptor proteins supported the pharmacological findings. This study is the first showing that molecules designed to bear thiazole and piperazine moieties together on their structure exert centrally and peripherally mediated antinociceptive effects by activating the opioid system.     

Chemoenzymatic route to optically active dihydroxy cyclopenta[b]naphthalenones; precursors for decalin-based bioactive natural products

The development of an efficient chemoenzymatic route for the synthesis of optically active dihydroxy cyclopenta[b]naphthalenones; (+)-1,4a-dihydroxy-4a,5,6,7,8,8a,9,9a-octahydro-1H-cyclopenta[b]naphthalen-2(4H)-one (+)-10 and (+)-1,8a-dihydroxy-4a,5,6,7,8,8a,9,9a-octahydro-1H-cyclopenta[b]naphthalen-2(4H)-one (+)-11 is described. Different lipases and esterases were tested in the enzymatic hydrolysis of the corresponding acetates (±)-4a-hydroxy-2-oxo-2,4,4a,5,6,7,8,8a,9,9a-decahydro-1H-cyclopenta[b]naphthalen-1-yl acetate (±)-8, (±)-8a-hydroxy-2-oxo-2,4,4a,5,6,7,8,8a,9,9a-decahydro-1H-cyclopenta[b]naphthalen-1-yl acetate (±)-9, CRL (Candida Rugosa Lipase) and PLE (Pig Liver Esterase) were found to be the most effectual enzymes; for (?)-8 by 47% ee with the corresponding dihydroxy; (+)-10 by 98% ee in the presence of CRL; whereas, (?)-8 was obtained with 40% ee with the corresponding dihydroxy, (+)-10 with 58% ee in the PLE hydrolysis. It was concluded that CRL was the best biocatalyst for the substrate (±)-8. Moreover, enzymatic resolution in the presence of CRL yields, (?)-9 with 46% ee with the corresponding dihydroxy derivative; (+)-11 with 98% ee; however, in the presence of PLE, yields (?)-9 with 36% ee as well as the related dihydroxy derivative; (+)-11 with 49% ee respectively. The study concluded that CRL is the best biocatalyst for compounds (±)-8 and (±)-9.     

DressBoard: An Embedded Virtual Try-On System for Ties and Bowties

In real life, trying a dress is generally physically exhausting and time consuming. In this study, a novel embedded virtual try-on system for ties and bowties is proposed, which will save time and enhance the shopping experience. The presented system is based on human computer interaction with embedded design, where the goal is to simulate tie/bowtie trial on a person in the camera view. Users can choose a tie/bowtie model available in the database via a touch screen. The system will then fit the selected model rapidly and accurately, and display the fitting result. Performance of the proposed system is experimentally evaluated on images acquired in a real-life scenario. The results showed that both fitting accuracy and process time vary almost-linearly with image resolution, where real-time and accurate (average error varies in the 0.5–5.0 cm range by resolution) performance can be achieved. In addition, the proposed system can handle fitting in videos, where experimental evaluations revealed real-time, accurate, and robust (to illumination change and image variations) performance even in the absence of collared garment.     

Novel functional copolymers based on glycidyl methacrylate: Synthesis,characterization, and polymerization kinetics

A new methacrylate monomer 2-(4-nitrophenyl)-2-oxoethyl-2-methacrylate (NFM) was synthesized and its radical copolymerization with glycidyl methacrylate (GMA) was studied in 1,4-dioxane solution at 65°C using 2,2′-azobisisobutyronitrile as an initiator. The synthesized monomer and copolymers were characterized by FTIR, ¹H and ¹³C-NMR spectroscopy. The analysis of reactivity ratios revealed that NFM is less reactive than GMA, and copolymers formed are statistically in nature. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with an increasing in the mole fraction of NFM in the copolymers. Glass transition temperatures of the copolymers decreased with an increasing of NFM molar fraction in copolymers. In addition, according to the results obtained from the contact angle and zeta potential measurements the hydrophobic character of the polymer decreases (it means surface free energy increases) and its zeta potential becomes more negative with increase of NFM ratio in the copolymer. Polymers with carbonyl functional groups have been particularly interesting because of their use as photoresists.     

Bubbly cavitating flow generation and investigation of its erosional nature for biomedical applications

This paper presents a study that investigates the destructive energy output resulting from hydrodynamic bubbly cavitation in microchannels and its potential use in biomedical applications. The research performed in this study includes results from bubbly cavitation experiments and findings showing the destructive effects of bubbly cavitating flow on selected solid specimens and live cells. The bubbles generated by hydrodynamic cavitation are highly destructive at the surfaces of the target medium on which they are carefully focused. The resulting destructive energy output could be effectively used for biomedical treatments, such as destroying kidney stones (renal calculi) or killing cancer cells. Motivated by this potential, the cavitation damage to cancerous cells and material removal from chalk pieces (which possess similar material properties as some kidney stones) was investigated. Our results showed that cavitation could induce damage both on chalk pieces and leukemia/lymphoma cells. We discovered that hydrodynamic cavitation exposure had early and delayed effects on cancer cell survival. Hence, the potential of hydrodynamic bubbly cavitation generated at the microscale for biomedical treatments was revealed using the microchannel configuration as a microorifice (with an inner diameter of 147 μm and a length of 1.52 cm), which acts as the source of bubbly cavitating flows.     

Lensing and waveguiding of ultraslow pulses in an atomic Bose-Einstein condensate

We investigate lensing and waveguiding properties of an atomic Bose-Einstein condensate for ultraslow pulse generated by electromagnetically induced transparency method. We show that a significant time delay can be controllably introduced between the lensed and guided components of the ultraslow pulse. In addition, we present how the number of guided modes supported by the condensate and the focal length can be controlled by the trap parameters or temperature.     

Kinetic and thermodynamic approaches on thermal degradation of sepiolite crystal using XRD-analysis

Journal of Thermal Analysis and Calorimetry - A method was proposed to use XRD-data for thermal analyses of crystalline solids. Therefore, the XRD-pattern was recorded for natural and preheated...