have been proposed and several types are currently used for tissue ablation. The types of deflector shapes are bare, sidefiring and radial. Bare fiber optic deflectors (basic deflector geometry) transmit the laser energy in the same direction along the fiber. Side-firing optical fiber optical deflectors transmit laser light perpendicular to the fiber axis through specific direction and they are widely used in many medical applications, especially in the prostate tumor ablation [1]. One of the most popular deflector types is radial design. Radial fiber optic deflectors with conically shaped optical fiber end transmit the laser energy radially and the laser energy is homogeneously distributed into a ring-shaped beam. These deflectors are especially used in endovenous laser ablation (EVLA) [2]. Unlike other cone-shaped fiber optical probes [3][4][5][6][7] used for various applications, EVLA operation needs μm-scale, multimode (MM) optical fibers and specific cone-angle values to fulfill the EVLA operation requirements. Thus, multi-mode, larger NA and μm-scale optical fibers are preferred in the operations. The homogeneous, ring-shaped laser energy distribution can be achieved with large cone angles which are detailed in this study. It allows a perfect irradiation of vein walls and their ablation. Among existent fiber processing methods such as chemical, FIB [3][4][5], mechanical polishing method is the best candidate to obtain such desired cone-angles. Furthermore, mechanical polishing process is applicable for mass-production of conical shaped optical fibers used in EVLA operation. In the mechanical polishing process, the deflector geometry is first formed with rough lapping film, then, the surface roughness of the deflector is gradually smoothed by polishing with smoother lapping films [8]. This process is composed of several steps to obtain high quality surface structures and a well-prepared fiber deflector surface eliminates the optical losses such as scattering and back reflection. However, the mechanical fining Abstract A novel method for polishing conical shaped optical fiber deflectors by modulated CO 2 laser exposure is reported. The conical shaped fiber deflector geometry was first formed with rough mechanical polishing, then it was exposed to modulated CO 2 laser operating with wavelength at 10.6 µm to achieve fine polish surfaces. The motivation of this work is to demonstrate that the modulated CO 2 laser exposure approach allows a fiber surface roughness at a nanometer scale without modifying the conical shape of the fiber deflector. The average surface roughness of mechanically polished fiber deflectors with 30 and 9 µm lapping films was smoothed down to 20.4 and 4.07 nm, respectively, after CO 2 laser polishing process. By combining mechanical and laser polishing techniques, fabrication of conical shaped optical fiber deflectors takes less time and it becomes laborer independent and easy to apply.
Recent clinical and epidemiological researches have declared that non-steroidal anti-inflammatory agents may display as antineoplastic agents and indicate pro-apoptotic and antiproliferative effects on cancer cells. The major purpose of this research was to develop a novel poly(ethyleneglycol)-block-poly(ε-caprolactone) (PEG-b-PCL) nano-sized particles encapsulated with nimesulide (NMS), a selective COX-2 inhibitor, and to evaluate its anticancer activity against MCF-7 breast cancer cells. NMS-encapsulated PEG-b-PCL nanoparticles were fabricated using three different production techniques: (i) by emulsion-solvent evaporation using a high shear homogenizer, (ii) by emulsion-solvent evaporation using an ultrasonicator, and (iii) by nanoprecipitation. Nanoparticles were evaluated with respect to the entrapment efficiency, size characteristics, drug release rates, thermal behavior, cell viability assays, and apoptosis. The resulting nanoparticles were found to be spherical shapes with negative surface charges. The average diameter of all nanoparticles ranged between 148.5 and 307.2 nm. In vitro release profiles showed that all nanoparticles exhibited a biphasic release pattern. NMS-loaded PEG-b-PCL nanoparticles demonstrated significant anticancer activity against MCF-7 breast cancer cells in a dose-dependent manner, and the effects of nanoparticles on cell proliferation were significantly affected by the preparation techniques. The nanoparticles developed in this work displayed higher potential for the NMS delivery against breast cancer treatment for the future.
electron transport properties and direct band gap structure, InN is a promising candidate for high-speed optoelectronic devices, broad-spectrum solar cells, high electron mobility transistors, near infrared light emitting diodes (LEDs) and high-speed laser diodes [2][3][4]. Furthermore, its nontoxic nature and infrared emission properties enable InN to be used in biological and medical applications [5]. Besides these advantageous properties of InN material, its nanostructures have been widely studied due to their different characteristics depending on the dimensionality and size, which allow the applications in nanoscale electronic and optoelectronic devices [6,7].InN crystallizes in two different structures: stable hexagonal (wurtzite) structure and metastable cubic structure. When compared to hexagonal InN, cubic InN possesses smaller band gap and superior electronic properties due to its isotropic lattice and lower phonon scattering [8]. However, the production of cubic InN-NCs is quite a challenging process due to its thermodynamically unstable nature [9]. Previous studies showed a number of techniques viable for the synthesis of InN-NCs mainly having hexagonal structure. Ambient pressure and low-temperature liquid phase was proposed as a suitable method for the synthesis of nanoparticles having low decomposition temperatures. It was shown that wurtzite InN-NCs having 6.2 nm average diameter are successfully produced using this method. These colloidal wurtzite InN-NCs were post-treated with nitric acid to get rid of the metallic indium byproduct and finally InN nano-powder was obtained [10]. Moreover, activated reactive evaporation and nitrogen plasma annealing methods were proposed for the successful production of wurtzite InN-NCs and InN nanorods, respectively. It was suggested that the technique is applicable to produce InN-NCs by using low temperatures from indium nanostructures obtained by different techniques [11]. Xiao et al.Abstract Nanostructures of InN have been extensively investigated since nano-size provides a number of advantages allowing applications in nanoscale electronic and optoelectronic devices. It is quite important to obtain pure InN nanocrystals (InN-NCs) to reveal the characteristic features, which gain interest in the literature. Here, we proposed a new approach for the synthesis of ultra-small hexagonal InN-NCs by using suspension of micron-sized InN powder in ethanol with pulsed laser ablation method. The liquid environment, laser energy and ablation time were optimized and a post-synthesis treatment, centrifugation, was performed to achieve InN-NCs with the smallest size. Besides, the micron-sized InN powder suspension, as a starting material, enabled us to obtain InN-NCs having diameters smaller than 5 nm. We also presented a detailed characterization of InN-NCs and demonstrated that the formation mechanism mainly depends on the fragmentation due to laser irradiation of the suspension.
In the last few decades, nanoparticles have become key components in a variety of applications in nanotechnology, nanoengineering, and nanoscience. Pulsed laser ablation in liquids (PLAL) method is frequently preferred for fast and pure nanoparticle generation. There exists a wide range of metal and semi-conductor nanoparticles that are successfully synthesized by PLAL method. In our research, nanoparticle synthesis of different materials and their applications are pursued. After nanoparticle synthesis, the application research proceeds and the scope of the research spans many subjects ranging from sensor realization to biological applications.
ÖzetÇimlenme engelini aşmak için tohumların çeşitli ön işlemlerden geçirilmeleri zorunludur. Bu ön işlemlerin yanı sıra çimlenme engeli in vitro koşullar altında da giderilebilmektedir. Çalışmada, Robinia pseudoacacia L., Pinus nigra J. F. Arnold , Pinus sylvestris L., Acer negundo L., Capparis spinosa L. ve Lycium europaeum L. bitkilerinin tohumları çimlenme engelini gidermek için çeşitli yoğunluktaki vermikompost çayları ile muamele edilmiştir. Dört hafta süre ile inkübe edilen tohumlarda, vermikompost yoğunluklarına bağlı olarak tohumların, vermikompost ortamında olmayanlara oranla daha iyi bir çimlenme gösterdikleri gözlenmiştir. Çimlenmeyi olumlu yönde etkileyen vermikompost ve ürünlerinin fidanlık çalışmalarında kullanılabilecek hem pratik hem de faydalı bir ürün olduğu ortaya konulmuştur. AbstractIt is necessary to pre-treat the seeds in order to overcome the germination inhibition. In addition to this pre-treatment, germination inhibition should be overcome in vitro conditions. In this study, the seeds of Robinia pseudoacacia L, Pinus nigra J.F Arnold, Pinus sylvestris L, Acer negundo L, Capparis sipinosa L and Lycium europaeum L were treated with various concentrations of vermicompost tea for germination. It was observed that the seeds incubated for four weeks had better germination than those not in the vermicompost environment. Vermicompost and its products, which affect germination positively, have been proved to be both practical and useful product that can be used in nursery studies.
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