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In present study, a new blend polymer consisting of a pyrazole-derived polymer poly(1,3-diphenyl-1H-pyrazol-5-yl methacrylate) and poly(methyl methacrylate) was prepared solution mixing method. The blend polymer was spectrally characterized with FTIR and 1H-NMR techniques. TGA analysis showed that the blend polymer was stable up to 275.4 °C. A thin film of blend polymer was prepared by using spin coating technique. The UV measurements were obtained as a function of wavelength (300 – 700 nm). The optical and dispersion parameters were reported in detail. Transmittance was increased depending on the increasing wavelength whereas the reflectance decreased. The Transmittance value at 700 nm was measured as 97.55%, meaning the blend polymer was transparent. The refractive index at 700 nm was 1.37. The Urbach energy (Eu) and the optical band gap constant (Eg) were calculated to be 0.831 eV and 3.737 eV, respectively. The type of electronic transitions for polymer was determined as indirect allowed transition.

Migraine is a common and substantially debilitating disorder that may associate with allodynia, a marker of central sensitization in the pain circuits. Several unmet needs, like limited adherence to drugs due to adverse events and cost-effectivity, still occur in the prophylactic treatment of migraine. Transcranial direct current stimulation (tDCS) has recently been indicated to be beneficial in individuals with migraine with and without allodynia. However, to our knowledge, there are no studies evaluating the efficacy of six-month tDCS in migraine.This study was a randomized double-blind parallel-group sham-controlled five-month extension study after a one-month lead-in trial of tDCS in individuals with migraine. A total of 23 individuals with migraine with allodynia who completed the lead-in trial were recruited after their consent and were administered three consecutive sessions of 2-mA anodal 20-minute tDCS over the left primary motor cortex every month for an additional five months. Pain-related outcomes were determined using monthly headache diaries. Allodynia, depression, anxiety, and disability because of migraine also were assessed throughout the study.Improvements in allodynia levels, attack frequency, number of rescue medications, and attack duration were higher, and mostly gradual during the trial, in the active group. Migraine Disability Scale grades also were lower in the active group, whereas no between-group differences were found in depression and anxiety scores. Higher responder rates of migraine attack frequency (56.8% vs 25%), number of headache days (56% vs 16.7%), and migraine attack duration (90.9% vs 8.3%) were observed after six-month tDCS in the active group than in the sham group.Long-term extended tDCS is shown to be a safe, efficacious, and plausible modality for prophylactic treatment in individuals with migraine with allodynia.Long-term extended tDCS can alleviate allodynia, which is an indicator of drug resistance and chronicity, and meet the goals of prophylactic treatment in individuals with migraine with allodynia.

Novel isocoumarin-derived copolymer systems of 2-(isocoumarin-3-yl)-2-oxoethyl methacrylate (ICEMA) with methyl methacrylate (MMA) were prepared by free radical polymerization. The ICEMA monomer ratios at the copolymer compositions were found to be 25%, 48% and 64% ICEMA by integration method in 1H-NMR technique. Thermal decomposition studies of copolymer systems were performed by thermogravimetric analysis. Various kinetic methods were applied to determine thermal decomposition kinetics of poly(ICEMA:0.48-co-MMA) copolymer. The maximum rate loss temperatures of this copolymer shifted from 295.38 to 323.17 °C depending on the increasing heating rate from 5 to 20 °C/min. The thermal decomposition activation energies of copolymer were investigated in the conversion range of 7–19%, which were resulted to be 126.17 and 125.32 kJ/mol by Flynn–Wall–Ozawa and Kissinger’s methods, respectively. In addition, thermal decomposition process of the studied copolymer followed with a D1 solid-state mechanism, one-dimensional diffusion-type deceleration mechanism, at the optimum heating rate of 5 °C/min.

Abstract: Transcranial direct current stimulation (tDCS) studies in healthy volunteers have shown conflicting results in terms of modulation in pain thresholds. The aim of this study was to investigate how single session anodal tDCS and modulated tDCS (mtDCS) of distinct cortical areas affected pain and perception thresholds in healthy participants. Five different stimulation conditions were applied at different cortical sites to 20 healthy volunteers to investigate the effects of tDCS and mtDCS (20 Hz) on pain and perception thresholds. TDCS over the motor cortex (M1), mtDCS over the motor cortex, tDCS over the dorsolateral prefrontal cortex (DLPFC), mtDCS of the DLPFC, and mtDCS over the occipital cortex were the stimulation conditions. All of the stimulations were anodal. The stimulations were given in a randomized order at 20-minute intervals. For comparison, electrical pain and perception thresholds were obtained from the right middle finger before and during the tDCS. After each measurement, participants were asked to give a score to their pain. In repeated measures analysis of variance (RM-ANOVA) test, the Condition × Time interaction showed no significant influence on changes in pain, perception thresholds, and pain scores ( p = .48, p = .89, and p = .50, respectively). However, regardless of the condition types, there was a significant difference in pain and perceptual thresholds during tDCS ( p = .01, p = .025, respectively). Our findings did not support difference in pain and perception modulation by a single session anodal tDCS over M1 and DLPFC compared to the occipital cortex in healthy volunteers. The increase in all thresholds during tDCS, irrespective of conditions, and peripheral sensations, including an active control group, taken together, suggest a placebo effect of active tDCS. Future studies about pain and perception in healthy subjects should consider the level of experimental pain and a strong placebo effect.

The UV/VIS spectrophotometric scans were obtained to determine the opto-electronic properties of 2-oxo-2-(1-oxo-1H-isochromen-3-yl)ethyl methacrylate (other name: 2-(isocoumarin-3-yl)-2-oxoethyl methacrylate) compound thin film. The refractive index of compound at 700 nm was found to be 1.61. The values of the real part of the dielectric constant were higher than those of the imaginary part. The results indicated that the electronic transition responsible for the absorption was the indirect allowed one. The optical band gap constant and the Urbach energy corresponding to the width of the band tails of localized states were calculated to be 3.19 eV and 1.05 eV, respectively. From the results obtained, it is predicted that 2-oxo-2-(1-oxo-1H-isochromen-3-yl)ethyl methacrylate (OICEMA) compound can take place in the semiconductor class and play a role in the design of some electro-optic materials.

Amaç: Elektroretinografi (ERG) ve Görsel Uyarılmış Potansiyeller (GUP) görsel bir uyarana yanıt olarak retinada ve oksipital korteksteki primer görme alanında oluşan elektriksel etkinliği ölçen ve görme yollarını nesnel olarak değerlendirebilen önemli tanı araçlarıdır. Potansiyellerin oluşturulması için zenon ya da ışık yayan diyot (LED) ışık kaynağı kullanılabilmektedir. Farklı fiziksel özelliklere sahip olan bu iki ışık kaynağının GUP ölçümlerinde kullanıldığı az sayıda araştırmada, LED ışık kaynağı kullanılarak yapılan GUP kayıtlarında benzer ya da hafifçe daha düşük genlikler elde edildiği bildirilmiştir. Ancak her iki ışık kaynağı kullanılarak ölçülen ERG ve GUP kayıtlarını eş zamanlı olarak değerlendiren bir araştırma bulunmamaktadır. Bu araştırmada sağlıklı gönüllülerde zenon ve LED ışık kaynağı kullanılarak yapılan ERG ve GUP kayıtlarının karşılaştırılması amaçlanmıştır. Gereç ve Yöntemler:Araştırmanın örneklemi 21-30 yaş aralığındaki 31 gönüllü katılımcıdan oluşmaktadır. LED ve zenon ışık kaynağı ile hem sağ hem sol gözden sırası randomize edilerek ayrı ayrı ERG ve GUP kayıtları alındı. ERG kayıtlarındaki “a”, “b”, ve GUP kayıtlarındaki N2, P2 dalgalarının gecikme süreleri ve genlikleri “Eşleştirilmiş-t testi” ile karşılaştırıldı. Bulgular: ERG kayıtlarındaki “a” ve “b” dalgaları ile GUP kayıtlarındaki N2 ve P2 dalgalarının gecikme süreleri arasında fark saptanmadı. LED ışık kaynağı ile yapılan ERG kayıtlarındaki a ve b dalgalarının genlikleri ile GUP kayıtlarındaki N2 dalgasının genliği daha düşük bulundu. Sonuç: LED ışık kaynağı ile zenon lamba ile elde edilenlere büyük ölçüde benzer dalga morfolojisi ve sonuçları olan ERG ve GUP kayıtları elde edilebileceği gösterilmiştir. LED ışık kaynağı ile yapılan GUP ve ERG ölçümlerinde daha düşük genlikler elde edilmesinin önüne geçmek için monokromatik LED kullanılması, özel gözlük kullanılması gibi değişiklikler önerilmiştir. Ayrıca bulunan sonuçların farklı yaş grupları ve görme yolu patolojisi olan bireylerde yinelenmesine gereksinim duyulmaktadır.

In present study, thermal decomposition studies of a copolymer based the coumarin containing monomer 3-benzoyl coumarin-7-yl-methacrylate (BCMA) and methyl methacrylate [poly(BCMA:0.54-co-MMA:0.46)] were performed by thermogravimetric analysis (TGA). The temperature for maximum rate losses was increased from 384.81 °C to 407.45 °C with the increasing in heating rate from 5 °C/min to 20°C/min. The thermal decomposition activation energies of copolymer in the conversion range of 9% - 21% were resulted to be 212.98 kJ/mol and 210.30 kJ/mol by Kissinger’s and Flynn–Wall–Ozawa methods, respectively. The study of kinetic equations such as Coats-Redfern, Tang, Madhusudanan and Van-Krevelen methods exhibited that the thermal decomposition process of the studied copolymer was followed with a D3 mechanism, a three-dimensional diffusion type deceleration solid state mechanism, at the optimum heating rate of 20 °C/min.

Objectives Allodynia, the clinical marker of central sensitization, affects even simple daily living activities and increases the tendency for migraine to be more resistant to treatment and have a chronic course. Migraine that impairs quality of life can often be treated with variable pharmaceutical agents, but with various side effects. Transcranial direct current stimulation (tDCS) is a potential alternative treatment for migraine prophylaxis. Materials and methods Seventy-seven patients diagnosed with migraine (48 with allodynia and 29 without allodynia) were included in the study. Randomly, 41 of the 77 patients received sham stimulation and 36 patients underwent three sessions of anodal left primary motor cortex stimulation for 2 mA, 20 min. Migraine attack characteristics (frequency, severity, and duration) and analgesic drug use were followed with headache diaries for one month after the stimulation. Results After tDCS, migraine attack frequency (p = 0.021), the number of headache days (p = 0.005), duration of attacks (p = 0.008), and symptomatic analgesic drug use (p = 0.007) decreased in patients receiving active tDCS, compared to the sham group. The therapeutic gain of tDCS was calculated as 44% (95% confidence interval [CI]: 22-60%) for headache days and 76% (95% CI: 55-86) for headache duration. Response to tDCS treatment was higher in patients without allodynia (60% vs. 24%; p = 0.028) and allodynia came out as an independent predictor of response to tDCS with logistic regression analysis. Side effects were rare and similar to the sham group. Conclusions tDCS is a safe, efficacious, and fast method for migraine prophylaxis. However, the administration of tDCS before allodynia occurs, that is, before central sensitization develops, will provide increased responsiveness to the treatment. Significance tDCS is more effective before the development of allodynia, but it also improves the quality of life even after the development of allodynia.

1Department of Chemistry, Faculty of Science and Arts, Adiyaman University, Adiyaman/Turkey 2Department of Engineering Basic Sciences, Faculty of Engineering and Natural Sciences, Malatya Turgut Özal University, Malatya, Turkey 3Department of Pharm. Chemistry, Pharmacy Faculty, Adiyaman University, Adiyaman/Turkey A coumarin derivative, namely 4-chloromethyl-7-hydroxy coumarin (CMEHC), was synthesized in order to test the concentration and solvent effect on its optical properties. The spectral characterization of this compound was accomplished by FTIR and 1H-NMR techniques. The UV absorption spectra of CMEHC compound in various solvents (THF, DMSO, DMF) were recorded with a UV–VIS spectrophotometer. The optical parameters such as maximum peak position, absorption band edge, and direct allowed bandgap were reported for these solvents and also various concentrations. The lowest direct allowed bandgap was obtained with THF. The absorbance spectra of CMEHC compound were dominant at the near ultraviolet region. The refractive index values were compared with each other using Moss, Ravindra, Herve-Vandamme, Reddy and Kumar-Singh relations.

In present study, the synthesis, characterization, and thermal properties of novel coumarin cyclic polymer poly(3-benzoyl coumarin-7-yl-methacrylate) polymer/montmorillonite based nanocomposites were performed. At the characterizations of nanomaterials FTIR, XRD, DSC and TGA techniques were used. It was determined from XRD measurements that the morphologies of nanocomposites were shifted from exfoliated type to intercalated type when the clay ratio in the coumarin polymer matrix was increased from 1 to 5% level. From DSC analysis, a partial increasing at the glass transition temperatures of nanocomposites was observed related to clay ratios. On the other hand, a positive correlation was observed between the clay ratio and thermal stability of nanomaterials from TGA analysis. Also, the increasing of decomposition temperatures of nanocomposites according to homopolymer was recorded to be 9–17°C.

In present study, thermal degradation kinetics of a new methacrylate polymer containingcoumarin side group, poly(3-benzoyl coumarin-7-yl-methacrylate), was investigated in detail. For this purpose,thermogravimetric analysis (TGA) was performed by applying a controlled heating program at different heatingrates to specific amounts of polymer samples. When the TGA results were examined, it was concluded that thethermal stability of polymer was higher with increasing the heating rate. Decomposition activation energies ofpolymer were calculated as 155.01 kJ mol-1 and 165.29 kJ mol-1 according to Flynn-Wall-Ozawa and Kissingermethods, respectively. Coats-Redfern method was also used to investigate the thermal decomposition mechanismof polymer. In the light of obtained kinetic data, it was determined that the thermal decomposition mechanism ofcoumarin derived polymer was followed by D1 one dimensional diffusion type deceleration mechanism at 10 °Cmin-1 optimum heating rate., Yan grup olarak kumarin halkasını barındıran ve yeni bir metakrilat polimeri olan poli(3-benzoil kumarin-7-il-metakrilat) polimerinin termal bozunma kinetiği mevcut çalışmada detaylıca araştırıldı. Bu amaçla, belirlimiktardaki polimer örneklerine farklı ısıtma hızlarında kontrollü bir ısıtma programı uygulanarak termogravimetrikanalizi (TGA) yapıldı. TGA sonuçları incelendiğinde, ısıtma hızı artışı ile polimerin termal kararlılığının dahayüksek olduğu sonucuna varıldı. Polimerin termal bozunma aktivasyon enerjisi Flynn-Wall-Ozawa metoduna göre155.01 kJ mol-1 ve Kissinger metoduna göre ise 165.29 kJ mol-1 olarak hesaplandı. Polimerin termal bozunmamekanizmasını belirlemek amacıyla Coats-Redfern kinetik metodu kullanıldı. Elde edilen kinetik veriler ışığındapolimerin termal bozunma mekanizmasının optimum 10 °C dak-1 ısıtma hızında D1 tek boyutlu difüzyon tipiyavaşlama mekanizması üzerinden ilerlediği belirlendi.

A novel isocumarin derived polymer poly(2-(isocoumarin-3-yl)-2-oxoethyl methacrylate) poly(ICEMA) was synthesized by free radical polymerization. The spectral characterization was performed with FTIR and 1H,13C-NMR techniques. The glass transition temperature of poly(ICEMA) was measured to be 161.69 °C by DSC technique. The initial decomposition temperatures obtained from TGA showed a change in the positive direction from 256.59 °C to 286.10 °C as the heating rate increased to 20 °C/min. Thermal decomposition activation energies of poly(ICEMA) in the conversion range of 7% - 19% were found to be 136.12 kJ/mol and 134.83 kJ/mol by Flynn–Wall–Ozawa and Kissinger’s models, respectively. In addition, various integral models such as Coats-Redfern, Tang, Madhusudanan and Van-Krevelen models were used to determine the thermal decomposition mechanism of poly(2-(isocoumarin-3-yl)-2-oxoethyl methacrylate)which showed that it proceeded at the optimum heating rate of 5 ºC/min over the D1 one-dimensional diffusion type deceleration mechanism

Objectives Transcranial direct current stimulation (tDCS) is a non-invasive and safe method tried in drug-resistant epilepsies, in recent years. Our aim was to evaluate the effect of tDCS in patients diagnosed with mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) which is a well-known drug-resistant focal epilepsy syndrome. Patients and methods Twelve MTLE-HS patients diagnosed with their typical clinical, EEG and MRI findings fulfilling the criteria for drug-resistance as suggested by the ILAE commission were included after Ethics Committee approval and their signed consent. All patients received modulated cathodal stimulation; 2 mA for 30 min on 3 consecutive days. All patients also received sham stimulation with the same electrode positions; designed as 60 s stimulation gradually decreasing in 15 s with placement of the electrodes for 30 min over the stimulation side. They were followed up by standard seizure diaries and their medical treatment was not changed during the study period. Their seizure frequencies both before and after cathodal tDCS and sham stimulation were compared statistically. Adverse effects were also questioned. Results Mean age of our study group was 35.42 ± 6.96 (6 males; median: 35.50). The mean seizure frequency was 10.58 ± 9.91 (median = 8; min-max = 2-30) at the baseline and significantly decreased to 1.67 ± 2.50 (median = 0.5; min-max = 0-8) after cathodal tDCS application (p = 0.003). Ten patients (83.33%) had more than 50% decrease in their seizure frequencies after cathodal tDCS. Two patients (16.67%) also showed positive sham effect. Six patients (50%) were seizure-free in the post-cathodal tDCS period of one month. No adverse effect has been reported except tingling sensation during cathodal stimulation. Conclusion Our small series suggested that cathodal tDCS may be used as an additional treatment option in MTLE-HS. It may be tried in TLE-HS patients waiting for or rejecting epilepsy surgery or even with ineffective surgery results. More studies are needed with large series of patients to investigate the effects of tDCS in drug resistant epilepsies.

We performed a comparative spectroscopic analysis on three novel Tm3+:tellurite-based glasses with the following compositions Tm2O3:TeO2-ZnO (TeZnTm), Tm2O3:TeO2-Nb2O5 (TeNbTm), and Tm3+:TeO2-K2O-Nb2O5 (TeNbKTm), primarily for 2-μm laser applications. Tellurite glasses were prepared at different doping concentrations in order to investigate the effect of Tm3+ ion concentration as well as host composition on the stimulated emission cross sections and the luminescence quantum efficiencies. By performing Judd–Ofelt analysis, we determined the average radiative lifetimes of the 3H4 level to be 2.55 ± 0.07 ms, 2.76 ± 0.03 ms and 2.57 ± 0.20 ms for the TeZnTm, TeNbTm and TeNbKTm samples, respectively. We clearly observed the effect of the cross-relaxation, which becomes significant at higher Tm2O3 concentrations, leading to the quenching of 1460-nm emission and enhancement of 1860-nm emission. Furthermore, with increasing Tm2O3 concentrations, we observed a decrease in the fluorescence lifetimes as a result of the onset of non-radiative decay. For the 3H4 level, the highest obtained quantum efficiency was 32% for the samples with the lowest Tm2O3 ion concentration. For the 1860-nm emission band, the average emission cross section was determined to measure around 6.33 ± 0.34 × 10−21 cm2, revealing the potential of thulium-doped tellurite gain media for 2-μm laser applications in bulk and fiber configurations.

Effects of anodal transcranial direct current stimulation (tDCS) of the motor cortex on heart rate variability (HRV) indices in healthy volunteers were examined. Baseline HRVs of 16 healthy subjects were recorded, and the HRV changes during anodal and sham tDCS stimulation over the vertex were observed. RM-ANOVA showed significant changes in the means of the high-frequency (HF) band, lowfrequency (LF) band, and LF/HF ratio (P < 0.0001, P = 0.012, and P = 0.01, respectively). A significant decrease in the LF/HF ratio was found during tDCS as compared to baseline (P = 0.033); this effect was mainly due to an increase in the HF band during active stimulation (P = 0.002 in active vs. baseline, and P = 0.007 in active vs. sham). A slight statistically insignificant decrease in the LF band and increase in the HF band induced a significance in comparison of the LF/HF ratio during sham stimulation. The increase in the HF HRV component reflects intensification of parasympathetic activity during anodal stimulation of the motor cortex. Possible explanations are activation of the motor cortex or a dominancy of the left hemisphere due to lateralized current flow. According to our results, neuromodulation of the motor cortex can be an adjuvant to maintain the autonomic balance in some neurological diseases. WOS:000440051900007 Q4

Novel nanocomposites of benzofuran-containing polymer poly(2-(5-bromo benzofuran-2-yl)-2-oxoethyl methacrylate) with different contents of organoclay were prepared and characterized with FTIR, XRD and SEM techniques. The thermal decomposition temperature of poly(BOEMA)/organoclay nanocomposites is higher than that of pure poly(BOEMA) about 5–14 °C at 10 % weight loss. The optical characterization was tested with a UV–VIS spectrophotometer. Transmittances of nanocomposites decreased to lower values by organoclay loading. Dispersion parameters such as steepness parameter, single-oscillator parameter, average oscillator position and strength, and moments of the imaginary part of the optical spectrum were changed as a function of organoclay nanofiller. As the organoclay content increased to 5 % in the polymer matrix, the existence of wide-band tails increased to 1.30 eV whereas the optical energy gap decreased to 2.92 eV. Analysis reveals that the type of transition is the indirectly allowed one.

Confocal microscopy has become a vital technique for life sciences due to higher lateral and axial resolution it provides compared to standard epifluorescence microscopy. On the contrary, accessibility to confocal microscopes did not escalate in proportion to its usage around the globe. Therefore, it was aimed to build an opto-digital confocal microscope, eventually leading to a product which will be affordable for research groups, institutes and hospitals. In this work, we present a home-built confocal microscopy setip using commercially available equipment. The design of the setup was realized using a 488 nm laser, an inverted microscope and optical/optomechanical parts including mirrors, lenses, beam splitter, scan lens. In addition, X-Y galvo scanner was controlled by using a custom-built control electronics. Instrumentation was made using a National Instruments DAQ card and LabVIEW based software. For characterization purposes reference samples were successfully imaged, following imaging of biological specimen. Gained know-how during development and prototyping will contribute vastly to process of producing a robust, desktop, easy to use and affordable confocal microsocope for researchers and organizations at a diverse scale.

Elastic light scattering is performed in the original band of optical fiber communication at 1300 nm for a 500 μm sapphire microsphere placed on a silica optical fiber half coupler. The morphology dependent resonances (MDRs) are observed in the transverse magnetically (TM) polarized and transverse electrically (TE) polarized 0∘ transmission and 90∘ elastic scattering obtained from the sapphire microsphere. The TE and TM MDRs can be detected selectively with the use of a Glan polarizer. The TE and TM polarization selectivity provides the ability to select relative MDR to BG levels. The TM polarization provides higher MDR signal to background ratio (SBR) and is suitable for optical monitoring, biological sensing or any other optoelectronic application that requires a high resolution optical filter. The polar angular mode spacing of 0.36 nm of the resonances correlates well with the optical size of the sapphire microsphere. The autocorrelation of the 90∘ elastic scattering spectra also shows peaks at 0.36 nm. The spectral linewidths of the resonances are on the order of 0.1 nm, which corresponds to quality factors on the order of 104. A sapphire sphere with a radius of 500 μm and relative refractive index of 1.31, resonances will red-shift by 1.01 nm (0.077%). This shift is on the order of 10 linewidths, making sapphire biophotonic sensors an interesting alternative to silica biophotonic sensors.

The miscibility behavior of poly(ethyl methacrylate) [poly(EMA)] with poly(2-hydroxy-3-phenoxypropyl methacrylate) [poly(PPMA)] was studied by DSC technique. Thermogravimetric analysis was used to investigate the thermal degradation mechanism and activation energies for initial decomposition process under non-isothermal conditions by integral approximation methods. The reaction mechanism of decomposition process using the kinetic equations of Coats–Redfern method was described by kinetic equations of phase-boundary-controlled reaction, R 3 mechanism. The activation energies for R 3 mechanism are very close to the values obtained in both Kissinger (115.6 kJ/mol) and Flyn–Wall–Ozawa (121.1 kJ/mol) methods. The optical and dispersion parameters such as refractive index, extinction coefficient, steepness parameter, single-oscillator energy and dispersion energy of blend polymer were determined in the visible range as a function of wavelength. The energy of Urbach corresponding to the width of the band tails of localized states and the optical band gap constant were calculated to be 1.08 and 3.33 eV, respectively.

Acquiring functional near infrared spectroscopy (fNIRS) and functional magnetic resonance-imaging (fMRI) data are usually done asynchronously. In order to correlate these two different modalities’ data, measurements must be performed at the same time. In this study, we have designed a new MR compatible continuous wave intensity based fNIRS device to overcome this problem. For MR compatible fNIRS, we used two LEDs with wavelengths at 660 and 870 nm. There are four photodiodes for light detection. LEDs operated in a sequential multiplexing mode with adjustable "on" time for each LED. Emitted and diffused light was transferred to and from the tissue through 10 m long single mode plastic optical fibers (INDUSTRIAL FIBER OPTICS, INC.). By using fibers, we overcome MR compatibility problems that can be caused by semi-conductors on probe. This MR compatible fNIRS design can provide synchronous measurements with low cost.

Rasmussen encephalitis is associated with severe seizures that are unresponsive to antiepileptic drugs, as well as immunosuppressants. Transcranial direct current stimulation (t-DCS) is a non-invasive and safe method tried mostly for focal epilepsies with different aetiologies. To date, there is only one published study with two case reports describing the effect of t-DCS in Rasmussen encephalitis. Our aim was to investigate the effect of t-DCS on seizures in Rasmussen encephalitis and to clarify its safety. Five patients (mean age: 19; three females), diagnosed with Rasmussen encephalitis were included in this study. Patients received first cathodal, then anodal (2 mA for 30 minutes on three consecutive days for non-sham stimulations), and finally sham stimulation with two-month intervals, respectively. Three patients received classic (DC) cathodal t-DCS whereas two patients received cathodal stimulation with amplitude modulation at 12 Hz. Afterwards, all patients received anodal stimulation with amplitude modulation at 12 Hz. In the last part of the trial, sham stimulation (a 60-second stimulation with gradually decreasing amplitude to zero in the last 15 seconds) was applied to three patients. Maximum current density was 571 mA/m2 using 70 mm x 50 mm wet sponge electrodes with 2-mA maximum, current controlled stimulator, and maximum charge density was 1028 C/m2 for a 30-minute stimulation period. After cathodal stimulation, all but one patient had a greater than 50% decrease in seizure frequency. Two patients who received modulated cathodal t-DCS had better results. The longest positive effect lasted for one month. A second trial with modulated anodal stimulation and a third with sham stimulation were not effective. No adverse effect was reported with all types of stimulations. Both classic and modulated cathodal t-DCS may be suitable alternative methods for improving seizure outcome in Rasmussen encephalitis patients.

We report a low-threshold continuous-wave Tm:YAG laser that can be excited near 785 nm with low-cost, single-mode AlGaAs laser diodes. Low-threshold operation was achieved using a tightly focused, astigmatically compensated x-cavity containing a 2-mm-thick Tm:YAG crystal with 5 % Tm3+ concentration. Two linearly polarized single-mode diodes operating at 785.8 nm were polarization coupled to end pump the resonator. With a 6 % output coupler, as high as 32 mW of output power could be obtained at 2016 nm with 184 mW of incident pump power. The output could be further tuned in the 1935–2035 nm range. Slope efficiency measurements indicated that cross-relaxation was very effective at this doping level. With a 2 % output coupler, lasing could be obtained with as low as 32.3 mW of pump power. In the limit of vanishing output coupling, the incident threshold pump power could be reduced to as low as 25 mW. To our knowledge, this is among the lowest lasing thresholds reported to date for continuous-wave, room-temperature thulium lasers.

The preparation of graft copolymers of poly(methyl methacrylate) with some alkyl methacrylates were carried out via atom transfer radical polymerization method catalyzed by CuCl/2,2′-bipyridine and using a macroinitiator, poly[(methyl methacrylate)-co-(3,5-bis(chloroacetoxy)phenyl methacrylate)], including an amount of 1 mol % having α-halogeno carbonyl group in the side groups. Although the number-average molecular weights of a graft copolymer series of n-butyl methacrylate (n-ButMA) ended at different times increased from 55,700 to 99,500, the polydispersities decreased from 1.85 to 1.39 with time. The thermal degradation kinetics of macroinitiator and a two-armed graft copolymer of n-ButMA with this macroinitiator, PMMA-g-PnButMA: 4% (by mol), were carried out at different heating rates by thermogravimetric analysis and the results were compared. Using both the Flynn–Wall–Ozawa and Kissinger methods, the decomposition activation energies for macroinitiator were determined as 168 and 162 kJ/mol, respectively; they were also calculated as 233 and 239 kJ/mol for PMMA-g-PnButMA: 4%. The solid state thermodegradation mechanisms of both macroinitiator and PMMA-g-PnButMA: 4% are R1-type mechanism, a phase boundary-controlled reaction, and F1-type mechanism, a random nucleation with one nucleus on the individual particle, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

We employed various low-cost dispersion compensation methods to generate femtosecond pulses from a Kerr-lens mode-locked (KLM) Cr:ZnSe laser operating near 2400 nm. Prism pairs made of CaF2 and MgF2 and slabs of BK7 and YAG were tested. Pulses as short as 92 fs were obtained when a CaF2 prism pair was used in the resonator with a 1% output coupler. With a 6% output coupler and CaF2 prism pair, pulse energies as high as 1.8 nJ were obtained. The KLM operating point was further analyzed for different dispersion compensation scenarios by using the soliton area theorem to determine the nonlinear refractive index (n 2) of Cr:ZnSe. Results gave an n 2 value of (1.2±0.2)×10−18 m2/W in agreement with previous reports.

Mevcut çalışmada, kumarin türevli yeni bir monomer olan3-benzoil kumarin-7-il-metakrilat (BKMA) monomerinin metil metakrilat (MMA) ilefarklı bileşimlerde bir seri kopolimeri hazırlandı. Bu amaçla serbest radikalpolimerizasyon yöntemi kullanıldı. Spektral karakterizasyonlar FTIR ve 1H-NMRteknikleri ile başarıldı. Kopolimer sistemlerinin bileşimleri 1H-NMRspektrumlarından belirlendi. DSC analizinden kopolimer bileşimindeki BKMA oranı%23 seviyesine düştüğünde camsı geçiş sıcaklığında 179 oC’den 165 oC’yebir azalış görüldü. Poli(BKMA) homopolimeri ve %54 BKMA bileşimli kopolimerinTGA analizinde her iki polimer için başlangıç bozunma sıcaklıkları sırasıyla321 oC ve 311 oC olarak kaydedildi., In present study, a copolymer series of a newcoumarin derived monomer 3-benzoyl coumarin-7-yl-methacrylate (BKMA) monomerwith methyl methacrylate (MMA) at different compositions was prepared. For thispurpose, free radical polymerization method was used. Spectralcharacterizations were performed by FTIR and 1H-NMR techniques.Copolymer compositions were determined with 1H-NMR spectra. From DSCanalysis, the glass transition temperature of copolymers was decreased from 179oC to 165 oC when the level of BKMA ratio decreased to23% level. In TGA analysis of poly(BKMA) homopolymer and the copolymer with 54%BKMA ratio, the initial decomposition temperatures of both polymers wererecorded to be 321 oC and 311 oC, respectively.

The reaction mechanism of decomposition process and the kinetic parameters of the poly(n-butyl methacrylate-b-styrene), poly(nButMA-b-St), diblock copolymer synthesized by atom transfer radical polymerization (ATRP) were investigated by thermogravimetric analysis (TGA) at different heating rates. TGA curves showed that the thermal decomposition occurred in one stage. The apparent activation energies of thermal decomposition for copolymer, as determined by the Kissinger's, Flynn–Wall–Ozawa and Tang methods, which does not require knowledge of the reaction mechanism (RM), were 112.52, 116.54, and 113.41 kJ/mol, respectively. The experimental results were compared with master plots, in the range of the Doyle approximation. Analysis of experimental results suggests that in the conversion range studied, 3–18%, the actual RM is an A2 sigmoidal type. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Atom transfer radical polymerization (ATRP) of three-armed polystyrene[PS] and poly(styrene-b-isobutyl methacrylate)[PS-b-PiBμMA] were accomplished using an initiator with tri-active C-Br end group function and cuprous (I) bromide/2,2′-bipyridyne catalytic system. The characterization obtained by FT-IR, 1H-NMR, and GPC techniques. The average molecular weight and polydispersity of PS and PS-b-PiBμMA were determined as 19,800, 29,300 and as 1.37 and 1.15, respectively, which indicates that the constant concentration of growing chains are present throughout the polymerization. The refractive index and extinction coefficient of the samples were determined in the visible range as a function of wavelength. The refractive index dispersion curves of the thin films were fitted by the Cauchy-Sellmeier model. The width of localized states (Eu) values changed inversely with optical band gaps (Eg) of the films. While the calculated Eu values of films for initiator, PS and PS-b-PiBμMA were determined as 2.72, 2.98, and 2.94 eV, the Eg values were determined as 3.43; 3.11, and 3.16 eV, respectively. The dispersion parameters of thin films were determined. These parameters changed in the investigated wavelength ranges. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Silicon microspheres are transparent in the near-infrared telecommunication bands and can be used for electrophotonic integration. We have experimentally observed blue shifts in resonance wavelengths of an electrically driven silicon microsphere of 500 mu m in radius, in the near-infrared. We have used a distributed feed back (DFB) laser operating at 1475 nm, and applied electrical potential differences up to 9 V to the silicon microsphere. We have observed blue shifts in the resonance wavelengths up to 0.05 nm, which corresponds to a change in the refractive index of 10(-4). (C) 2008 Elsevier B.V. All rights reserved.

Using optical tweezers (OT) and a haptic device, microspheres having diameters ranging from 3 to 4 mu m (floating in a fluid solution) are manipulated in order to form patterns of coupled optical microresonators by assembling the spheres via chemical binding. For this purpose, biotin-coated microspheres trapped by a laser beam are steered and chemically attached to an immobilized streptavi d in -coated sphere (i.e., the anchor sphere) one by one using an xyz piezo scanner controlled by a haptic device. The positions of all spheres in the scene are detected using a CCD camera and a collision-free path for each manipulated sphere is generated using the potential field approach. The forces acting on the manipulated particle due to the viscosity of the fluid and the artificial potential field are scaled and displayed to the user through the haptic device for better guidance and control during steering. In addition, a virtual fixture is implemented such that the desired angle of approach and strength are achieved during the binding phase. Our experimental studies in virtual and real environments with eight human subjects show that haptic feedback significantly improves the user performance by reducing the task completion time, the number of undesired collisions during steering, and the positional errors during binding. To our knowledge, this is the first time that a haptic device is coupled with OTs to guide the user during an optical manipulation task involving steering and assembly of microspheres to construct a coupled microresonator., NA

We demonstrate resonant enhancement of energy transfer from donor to acceptor molecules in single glycerol/water microdroplets standing on a superhydrophobic surface. At donor emission wavelengths resonant with a whispering gallery mode, we recorded energy transfer rates up to 10 times higher than the non-radiative (Forster) energy transfer rate, by using the gradual acceptor photobleaching technique. Optical images taken with donor and acceptor emission filters revealed the radiative (long-range) nature of the energy transfer mediated by the whispering gallery modes.

We investigated the effect of Cr2+ concentration on the fluorescence lifetime, fluorescence efficiency, and lasing performance of Cr2+:ZnSe lasers. In the experiments, polycrystalline Cr2+:ZnSe samples with concentrations of 0.34 × 1018–66 × 1018 ion/cm3 were prepared by diffusion doping. Spectroscopic measurements performed with Cr4+:YAG and Tm3+:fiber lasers show that the fluorescence efficiency decreases monotonically with increasing active ion concentration. Lifetime measurements and lasing characterization were also performed with a pulsed 1570-nm KTP optical parametric oscillator. In gain-switched operation, the highest output energy was obtained with the Cr2+:ZnSe sample having a Cr2+ ion concentration of 14 × 1018 cm−3. The power performance degrades with increasing concentration due to larger passive losses at the lasing wavelength. Furthermore, the pulse build-up time and the output pulsewidth decrease with pump energy and ion concentration. Finally, with a single set of optics, tunable output could be obtained in the 2520–3050 nm wavelength range.

Using Laser applications in medical has become more and more popular. Especially, Laser tissue welding has the significant role for laser skin closure. Mechanical behaviour of the material can be determined by appliying tension to the material itself. In this study, surgical incisions which were made on the dorsal skin tissue of 6 wistar albino rats, were welded with 1940 nm diode laser. Tensile tests are designated the determined days (4,7) by excision of the welded skin tissue. There is no significant mechanical difference between 4 and 7 days(p=0,88, p=0,41). © 2015 IEEE. Medical Technologies National Conference, TIPTEKNO 2015 -- 15 October 2015 through 18 October 2015 -- -- 118954

1,3,5‐(2′‐Bromo‐2′‐methylpropionato)benzene was used as a three‐functional initiator in the synthesis of three‐armed star polymer of phenoxycarbonylmethyl methacrylate (PCMMA) and its copolymers with ethylmethacrylate (EMA) via the atom transfer radical polymerization (ATRP) with a Cu(I)Br/2,2′‐bipyridine catalitic system at 90°C. The homo‐ and copolymers were characterized by FT‐IR, 1H and 13C NMR techniques. The compositions of the copolymers were calculated from 1H‐NMR spectra. The diblock copolymer of poly(PCMMA‐b‐EMA) synthesized using poly(PCMMA) macroinitiator and Cu(I)Br/bpy catalitic system showed an inefficient polymerization of ethylmethacrylate with low molecular weight and higher polydispersity. The molecular weight and molecular weight distribution were obtained by Gel Permeation Chromatography (GPC). For this copolymerization system, their monomer reactivity ratios were obtained by using both Kelen‐Tudos and Fineman‐Ross equations. The thermal behavior of three‐armed poly(PCMMA) and its cop...

A simple method for the preparation of rare earth ion-doped polymers, which display luminescence, is reported. For this purpose silicone–urea copolymers were doped with Nd(NO3)3·6H2O. Various structural and physicochemical properties of the resultant materials were investigated. FTIR studies indicated strong interaction of Nd3+ ions with urea groups, but no interaction with siloxane backbone, which is expected. Absorption measurements in the visible and near infrared region were performed and the radiative decay rates and branching ratios for the meta-stable 4F3/2 level were determined by using Judd–Ofelt theory. The samples were also excited at 800 nm and emission spectra were observed in the near infrared at 905, 1059, and 1331 nm. In Nd3+ doped silicone–urea systems the highest emission cross section at 1059 nm was determined to be 60.7×10−21 cm2. Spectroscopic parameters determined in this study suggest that Nd3+ doped silicone–urea copolymers are promising candidates for the development of fiber lasers or amplifiers near 1.06 and 1.3 μm.

We investigated the near-infrared luminescence characteristics as a function of glass composition and Tm3+ ion concentration in a new type of Tm3+-doped tellurite glass: (1−x)TeO2–(x)PbF2. In the experiments, absorption measurements were first performed to determine the spontaneous emission probabilities and the radiative lifetimes for the 4f–4f transitions of the Tm3+ ions by using the Judd–Ofelt theory. Luminescence measurements show that with increasing thulium concentration, the strength of the 1470-nm band decreases with respect to that at 1800 nm due to cross relaxation. Emission cross sections were further determined as a function of host composition by using the luminescence data. For a fixed thulium concentration of 1 mol%, samples with x = 20 mol % had the highest emission cross sections at 1470 and 1800 nm. Finally, lifetime measurements showed that the luminescence quantum efficiencies of the 1470- and 1800-nm transitions were maximum for host compositions with x=20 and 22 mol%, respectively.

We investigated the effect of thulium ion concentration on the continuous-wave (CW) power performance of diode single-end-pumped thulium-doped YAlO/sub 3/ (Tm:YAP) lasers. Three samples with 1.5%, 3%, and 4% Tm/sup 3+/ concentration were examined at 18/spl deg/C. Lifetime and fluorescence measurements were further performed to assess the strength of cross relaxation and nonradiative decay. Our results showed that in single-end-pumped configurations, the best CW power performance was obtained with the 1.5% Tm:YAP sample, and laser performance of the samples degraded monotonically with increasing Tm/sup 3+/ concentration. By using 9.5 W of incident pump power at 797 nm, a maximum of 1430 mW of output power was obtained with the 1.5% Tm:YAP sample and 2% output coupler. We discuss how the effects of cross relaxation, reabsorption, nonradiative decay, and internal heating vary with increasing concentration. Spectroscopic measurements and rate-equation analysis suggest that cross relaxation should already be effective in samples with 1.5% Tm/sup 3+/ ion concentration and doping concentrations larger than 4% will lead to degradation in power performance due to higher nonradiative decay rates and larger reabsorption losses.

An animal model of sexual fetishism was developed with male Japanese quail based on persistence of conditioned sexual responding during extinction to an inanimate object made of terrycloth (Experiments 1 and 3). This persistent responding occurred only in subjects that came to copulate with the terrycloth object, suggesting that the copulatory behavior served to maintain the fetishistic behavior. Sexual conditioning was carried out by pairing a conditioned stimulus (CS) with the opportunity to copulate with a female (the unconditioned stimulus or US). Copulation with the CS object and persistent responding did not develop if the CS was a light (Experiment 1) or if conditioning was carried out with a food US (Experiment 2). In addition, subjects that showed persistence in responding to the terrycloth CS did not persist in their responding to a light CS (Experiment 3). The results are consistent with the hypothesis that conditioned copulatory behavior creates a form of self-maintenance that leads to persistent responding to an inanimate object. The development of an animal model of such fetishistic behavior should facilitate experimental analysis of the phenomenon.

We have used spectroscopic methods to investigate the effect of cross relaxation on the 1470 and 1800 nm emissions in Tm3+:TeO2–CdCl2 glass for Tm3+ ion concentrations of 0.05, 0.1, 0.25, 0.5 and 1.0 mol%. The emission spectra obtained under 800 nm excitation reveal the existence of energy transfer via cross relaxation among the Tm3+ ions. As a result, as the thulium concentration is increased, the strength of the 1470 nm emission is found to decrease in relation to that of the 1800 nm emission. The analysis of the time evolution of the 3F4 emission due to the transition further shows that the electronic mechanism responsible for the ion–ion interaction can be identified as an electric dipole–dipole energy transfer process and occurs in the diffusion-limited relaxation regime. The average critical distance parameter which provides a measure for the strength of cross relaxation was further determined to be 17.9 A.

Atom transfer radical polymerization conditions with copper(I) bromide/2,2 ′ -bipyridine (Cu/2,2 ′ -bpy) as the catalyst system were employed for the homopolymerization and random copolymerization of 1-phenoxycarbonyl ethyl methacrylate (PCMA) with methyl methacrylate (MMA). Temperature studies indicated that the polymerizations occurred smoothly in bulk at 110 °C. Poly(PCMA)(polydispersity index=1.27) homopolymer was characterized and then used as macroinitiator for increasing its molecular weight. The homopolymerization of PCMA was also carried out under free radical conditions using 2,2 ′ -azobisisobutyronitrile as an initiator. The monomer and polymers were characterized by FT-IR and 1 H and 13 C-NMR techniques. The glass transition temperatures, the solubility parameters and average-molecular weights of the polymers were determined. Thermal stabilities of the polymers were given as compared with each other by using TGA curves. Thermal degradation products of poly(PCMA)s obtained by ATRP and free radical polymerization were compared with each other by using 1 H-NMR technique.

Poly(n-butyl methacrylate) (PnBMA)-b-polystyrene (PS) (diblock), PnBMA-b-PS, and PnBMA-b-PS-b-PnBMA (triblock copolymers) were synthesized by atom transfer radical polymerization (ATRP), using PnBMA and PnBMA-b-PS with C-Br-end-group as macroinitiators. The diblock and triblock copolymers were characterized by 1H-NMR, FT-IR spectroscopy, and differential scanning calorimetry (DSC). The molecular weight and molecular weight distributions were obtained by gel permeation chromatography (GPC). Polymerization was controlled up to a molecular weight of 46,200, and the polydispersity index was 1.33. The experimental results showed that the polymerization was controlled/living. The thermal degradation behavior of the block copolymers was studied using thermogravimetry (TG) and a single line vacuum system consisting of a degradation tube with a condenser for product collection and a liquid nitrogen trap (−196°C). The block copolymers were heated from ambient temperature to 500°C. The products of degradati...

We present the results of a study which uses experimental and theoretical methods to investigate the characteristics of the 1450- and 1800-nm luminescence bands of Tm3+-doped TeO2–CdCl2 glasses as a function of the CdCl2 fraction. These glasses are potentially important in the design of fiber-optic amplifiers and fiber lasers. In the experiments, the glass samples were prepared by fusing a mixture of their respective reagent grade powders in a platinum crucible at 750 °C for 30 min. The spectroscopic properties were then investigated by measuring the absorption, fluorescence intensities, and the fluorescence lifetimes at room temperature by using diode and Ti:sapphire pump lasers operating around 800 nm. In the theoretical calculations, Judd–Ofelt analysis was used to assess the effect of the glass composition on the radiative transition probabilities, quantum luminescence efficiencies, and the stimulated emission cross-sections. The results indicate that the luminescence quantum efficiency, while remaining approximately constant around 10% for the 1450-nm band, increases with increasing CdCl2 concentration for the 1800-nm emission. Furthermore, the stimulated emission cross-sections for the 1450- and 1800-nm transitions were found to be largest for the sample with 30 mol% CdCl2.