Photoluminescent electrospun polymeric nanofibers incorporating germanium nanocrystals

Cataloged from PDF version of article.The photoluminescent germanium nanocrystals (Ge-NCs) were successfully incorporated into electrospun polymeric nanofiber matrix in order to develop photoluminescent nanofibrous composite web. In the first step, the synthesis of Ge-NCs was achieved by nanosecond pulsed laser ablation of bulk germanium wafer immersed in organic liquid. The size, the structural and the chemical characteristics of Ge-NCs investigated by TEM, XPS, XRD and Raman spectroscopy revealed that the Ge-NCs were highly pure and highly crystalline having spherical shape within 3–20 nm particle size distribution. In the second step, Ge-NCs were mixed with polyvinyl alcohol (PVA) polymer solution, and then, Ge-NC/PVA nanofibers were obtained via electrospinning technique. The electrospinning of Ge-NCs/PVA nanoweb composite structure was successful and bead-free Ge-NCs/PVA nanofibers having average fiber diameter of 185 ± 40 nm were obtained. The STEM analysis of the electrospun Ge-NCs/PVA nanofibers elucidated that the Ge-NCs were distributed homogeneously in the polymeric nanofiber matrix. The UV–Vis absorption and photoluminescence spectroscopy studies indicated the quantum confinement effect of Ge-NCs on the optical properties of the electrospun Ge-NCs/PVA nanoweb

A plasmonic enhanced photodetector based on silicon nanocrystals obtained through laser ablation

Cataloged from PDF version of article.We present a proof-of-concept photodetector which is sensitive in the visible spectrum. Silicon nanocrystals (Si-NCs) obtained by laser ablation are used as the active absorption region. Si-NC films are formed from a polymeric dispersion. The films are sandwiched between thin insulating films to reduce the electrical leakage current. Furthermore, Ag nanoparticles are integrated with the photodetector to enhance the visible response using plasmonic effects. The measured photocurrent is resonantly enhanced, which is explained in terms of enhanced local fields caused by localized plasmons. The UV-vis spectrum of Ag nanoparticles is also measured to verify the resonance. © 2012 IOP Publishing Ltd

Thin film MoS2 nanocrystal based ultraviolet photodetector

Cataloged from PDF version of article.We report on the development of UV range photodetector based on molybdenum disulfide nanocrystals (MoS2-NCs). The inorganic MoS2-NCs are produced by pulsed laser ablation technique in deionized water and the colloidal MoS2-NCs are characterized by transmission electron microscopy, Raman spectroscopy, X-ray diffraction and UV/VIS absorption measurements. The photoresponse studies indicate that the fabricated MoS2-NCs photodetector (MoS2-NCs PD) operates well within 300-400 nm UV range, with diminishing response at visible wavelengths, due to the MoS2-NCs absorption characteristics. The structural and the optical properties of laser generated MoS2-NCs suggest promising applications in the field of photonics and optoelectronics. (C) 2012 Optical Society of Americ

Enhanced memory effect via quantum confinement in 16 nm InN nanoparticles embedded in ZnO charge trapping layer

Cataloged from PDF version of article.In this work, the fabrication of charge trapping memory cells with laser-synthesized indium-nitride nanoparticles (InN-NPs) embedded in ZnO charge trapping layer is demonstrated. Atomic layer deposited Al2O3 layers are used as tunnel and blocking oxides. The gate contacts are sputtered using a shadow mask which eliminates the need for any lithography steps. High frequency C-Vgate measurements show that a memory effect is observed, due to the charging of the InN-NPs. With a low operating voltage of 4 V, the memory shows a noticeable threshold voltage (Vt) shift of 2 V, which indicates that InN-NPs act as charge trapping centers. Without InN-NPs, the observed memory hysteresis is negligible. At higher programming voltages of 10 V, a memory window of 5 V is achieved and the Vt shift direction indicates that electrons tunnel from channel to charge storage layer. © 2014 AIP Publishing LL

Successful myomectomy during pregnancy : A case report

BACKGROUND: The medical literature has reported an increase in myomectomy during caesarean section in the past decade. However, myomectomy performed during pregnancy remains a rarity. The management of uterine fibroids during pregnancy is usually expectant and surgical removal is generally delayed until after delivery. We present a case of a large, symptomatic uterine fibroid diagnosed during pregnancy which was successfully managed by antepartum myomectomy. CASE PRESENTATION: A 30 year old woman presented with a one year history of abdominal swelling, amenorrhea and severe epigastric discomfort of 19 weeks duration. The abdomen was grossly distended and tense. A sonographic diagnosis of ovarian tumor in pregnancy was made. Laparotomy revealed a 32 cm degenerating subserosal uterine fibroid co-existing with an intrauterine pregnancy. Myomectomy was successfully performed. The subsequent antenatal period was uneventful with a spontaneous vaginal delivery of a female baby at 38 weeks. CONCLUSION: This report supports other studies and case series that have demonstrated the safety of myomectomy during pregnancy in selected circumstances

Polarisation dynamics of vector soliton molecules in mode locked fibre laser

Two fundamental laser physics phenomena - dissipative soliton and polarisation of light are recently merged to the concept of vector dissipative soliton (VDS), viz. train of short pulses with specific state of polarisation (SOP) and shape defined by an interplay between anisotropy, gain/loss, dispersion, and nonlinearity. Emergence of VDSs is both of the fundamental scientific interest and is also a promising technique for control of dynamic SOPs important for numerous applications from nano-optics to high capacity fibre optic communications. Using specially designed and developed fast polarimeter, we present here the first experimental results on SOP evolution of vector soliton molecules with periodic polarisation switching between two and three SOPs and superposition of polarisation switching with SOP precessing. The underlying physics presents an interplay between linear and circular birefringence of a laser cavity along with light induced anisotropy caused by polarisation hole burning

TAXATION OF SOCIAL MEDIA ADVERTISEMENTS

AbstractToday, the use of Internet and in particular social media as advertising tools brings the question ofhow the advertisement in social media should be taxed. This is not only seen as a problem in our country,but in the international platform as well.In the first part of the study, the definition of social media is given; in the second part, Social MediaBrand Communities and Fun Pages are discussed; in the third part, a comparison of Social Media Contentsand Public Goods, Global Public Goods and Club Goods is made; in the fourth part that Conclusionand Suggestions how social media is taxed is discussed

An investigation of toxicity potential of nimesulide in juvenile rats [Juvenil si{dotless}çanlarda nimesulid'in toksisite potansiyelinin araşti{dotless}ri{dotless}lmasi{dotless}]

Nimesulide has been widely used in pediatry for treatment of inflammation associated to respiratory tract infections, fever, several chronic inflammatory conditions, and pain in many countries. However, very few but serious cases of adverse effects, particularly hepatic dysfunction and liver injury have been reported. Reactive oxygen species (ROS) has been implicated in nimesulide-induced adverse effects, including hepatotoxicity. However, several reports demonstrated the reducing effect of nimesulide on oxidative damage and its direct free radical scavenging activity. This study was performed to investigate the effects of nimesulide on oxidative stress and antioxidant enzymes in juvenile rats as well as its tissue damage potential. Four weeks-old Wistar albino, female rats were used. Nimesulide was given by gavage at two doses for 14 days. Blood and tissue samples were taken under pentobarbital anesthesia. Nimesulide treatment caused increase in plasma malondialdehyde (MDA) levels and decrease in catalase (CAT) and glutathione peroxidase (GPx) activities; superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G-6P-DH) activities were not changed. Tissue damage and changes in some serum parameters were also observed.Our results, indicating the possibility of tissue damage and alterations of oxidant/antioxidant status by nimesulide, might provide important contribution to the literature about the cautions for nimesulide use in juveniles

Becker's naevus and segmental naevus depigmentosus: An example of twin spotting?

A 12-year-old girl presented with a 1-year history of a Becker's naevus involving the right posterior thigh and gluteal area. In addition, three hypopigmented macules of naevus depigmentosus distributed in a segmental pattern on the medial aspect of the right posterior thigh had been present since birth. We suggest that their unusual coexistence in close proximity may represent an example of twin spotting