TiO2 photocatalysts

Son yıllarda, titanyum dioksit (TiO2) üzerinde, fotokatalitik aktivite özelliğinden dolayı yoğun olarak çalışılmaktadır. TiO2, UV ışığı ile uyarıldığı zaman fotoaktif özellik gösteren ve organik grupları parçalayabilen yarıiletken bir malzemedir. TiO2, ışığa maruz bırakıldığında, suyun arıtılmasında, kendi kendini temizleyebilen, buğulanmayan yüzeylerin elde edilmesinde, fotokimyasal olarak kanser tedavisi uygulamalarında, havanın arındırılmasında kullanılabilir. TiO2 filmler, kimyasal buhar biriktirme, sıçratma, elektron demeti ile buharlaştırma, iyon ışını destekli biriktirme ve sol-jel gibi yöntemlerle değişik yüzeyler üzerine kaplanabilirler. TiO2, anataz, rutil ve brukit olmak üzere üç farklı kristal yapıya sahiptir. Birçok uygulamada TiO2’in anataz formu en iyi fotoaktivite özelliği göstermektedir. TiO2’in, solar spektrumun çok az bir bölümünü oluşturan UV ışığı ile aktive edilebiliyor olması bu malzemenin pratik uygulamalardaki kullanımını sınırlandırmaktadır. Bundan dolayı, pratik uygulamalar için, TiO2’in fotoaktivitesinin geliştirilmesi gerekmektedir. Fotoaktiviteyi arttırmanın bir yolu, TiO2’in geçiş metalleri veya soy metallerle katkılandırma işlemi yaparak soğurma (absorption) bandının UV bölgesinden, görünür bölgeye kaydırılmasıdır. Literatürde, titanyum oksit filmlere gümüş, tungsten ve molibden katkılandırılmasına yönelik çalışmalar yapılmış ve üç katkılandırmanın da, titanyum oksit filmlerin fonksiyonalitesine farklı mekanizmalar üzerinden ciddi katkılar yapacak nitelikte olduğu belirtilmiştir. Bu çalışmada, TiO2’in fotokatalitik aktivite mekanizması tartışılmış ve TiO2’in kullanım alanları anti-bakteriyel özelliklerine odaklanarak özetlenmiştir. Buna ek olarak, gümüş, tungsten ve molibden katkısının TiO2’in, anti-bakteriyel aktivitesine olan etkileri tartışılmıştır.  Anahtar Kelimeler: TiO2, sol-jel, anti-bakteriyel, fotokatalitik aktivite.Recently, titanium dioxide (TiO2) has been studied extensively due to its high photocatalytic activity for handling of several types of environmental problems. Major areas of activity in TiO2 photocatalysis are; water purification, photochemical cancer treatment, air purification, self-sterilizing, fog-proof and self-cleaning surfaces. Photocatalysis can be defined as ?acceleration of a photoreaction by the presence of a photocatalyst?. Photocatalytic reactions necessitate a photocatalyst that absorbs the phonons and drives the redox reactions. TiO2 is a semiconductor and it can be chemically activated by UV light. TiO2 has three different crystal structures which are anatase, brookite and rutile. TiO2 in the anatase form is the most efficient of photocatalysts for many applications. The band gap energy of anatase TiO2 is 3.2 eV and it can be only activated by UV light. Although UV light is present in the solar spectrum it is only a very limited part. For practical applications the photocatalytic activity of TiO2 needs further improvement. Doping TiO2 with transition metals or noble metals is an effective way to improve photocatalytic activity. When TiO2 is exposed to UV light, electron-hole pairs are created. The photogenerated holes in the valence band, which has strong oxidizing power, diffuse to the surface and react with adsorbed water in order to produce hydroxyl radicals (?OH). These hydroxyl radicals participate in oxidizing organic molecules. On the other hand, electrons in the conduction band react with molecular oxygen in the air to produce the superoxide radical anion (O2-?), which also participates in further oxidation processes. The photocatalytic efficiency of TiO2 strongly depends on surface area and electron-hole recombination rate. The surface area of the photocatalyst increases with a smaller particle size and the active surface sites increase. For improving photocatalytic efficiency, electron-hole recombination rate should be reduced. An effective way to seperate electron-hole pairs is to introduce foreign materials into TiO2 matrix. As mentioned above, TiO2 can be used in different application areas. One of the remarkable property of TiO2 is its self-cleaning effect. The surfaces of glasses, ceramic tiles can be contaminated by organic particles such as smoke residue, oil and dirt. TiO2 thin films can be applied to these surfaces in order to decompose those organic species. Another excellent property of TiO2 photocatalysts is their anti-bacterial effect. TiO2 can decompose bacteria and virus when it is exposed to UV light. TiO2 has advantages over conventional self-sterilizing surfaces. For instance, in the case of E.coli, TiO2 decompose both the living cells as well as the endotoxin released from these cells during their death. TiO2 photocatalysts can also be used for cancer treatment. TiO2 particles which are injected to the tumor  clearly inhibit the tumor growth. In literature, there are several studies which are related to the doping effect of silver. Studies which are performed on the effect of silver dopant are focused on the change of optical and electronical properties of TiO2. Moreover, since silver itself is known as strong anti-bacterial agent it is used as dopant for improving anti-bacterial properties of TiO2. Doping silver can give rise to the separation of electron-hole pairs and can accelerate the formations of oxidative species. In addition to this, silver can reduce particle size which is needed for increasing surface area of TiO2. In order to obtain anti-bacterial effect in the dark, energy storage photocatalyst can be produced by doping TiO2 with tungsten. TiO2-WO3 photocatalyst can be photo-charged by irradiating their surfaces with UV light. Photo-charged tungsten doped TiO2 films are able to show anti-bacterial effect when the light is turned off. Molybdenum also is an energy storage material and it can be used as an alternative to those of tungsten. In this study, the mechanism of photocatalytic activity is discussed and the application fields of TiO2 photocatalysts were summarized by focussing on the bacterial activity of TiO2. Moreover, the effect of silver, tungsten and molybdenum dopants on the bacterial activity of TiO2 were discussed.  Keywords: TiO2, sol-gel, photocatalyst, anti-bacterial, photocatalytic activity

Choroidal Thickness in Patients with Mild Cognitive Impairment and Alzheimer’s Type Dementia

Aim. To asses both choroidal thickness differences among Alzheimer’s type dementia (ATD) patients, mild cognitive impairment (MCI) patients, and healthy control (C) subjects and choroidal thickness relationships with cognitive performance. Methods. A total of 246 eyes of 123 people (41 ATD, 38 MCI, and 44 healthy C subjects) were included in this study. Complete ophthalmological and neurological examination was performed in all subjects. Choroidal thicknesses (CT) were measured at seven locations: the fovea, 500-1500-3000 μm temporal and 500-1500-3000 μm nasal to the fovea by enhanced depth imaging optical coherence tomography (EDI-OCT). Detailed neurological examination including mini mental state examination (MMSE) test which evaluates the cognitive function was applied to all participants. Results. The ages and genders of all participants were similar in all groups. Compared with healthy C subjects, the CT measurements at all regions were significantly thinner both in patients with ATD and in patients with MCI than in healthy C subjects (p<0.05). The MMSE scores were significantly different among ATD patients, MCI patients, and healthy C subjects. They were 19.3±1.8, 24.8±0.9, and 27.6±1.2 in ATD, MCI, and healthy controls, respectively (p<0.001). There were also significant correlation between MMSE score and choroidal thickness at each location (p<0.05). Conclusions. CT was reduced in ATD patients and MCI patients. Since vascular structures were affected in ATD patients and MCI patients, they had thin CT. Besides CT was correlated with degree of cognitive impairment. Therefore CT may be a new biomarker in diagnosis and follow-up of MCI and ATD patients

Some properties of Cu-B4C composites manufactured by powder metallurgy

In this study, some properties of cold pressed Cu-B4C composites were investigated. Commercial copper powders with 40 &micro;m particle size were reinforced with B4C in a 40&micro;m particle size at ratios of 0, 1, 2, 3 wt.% for improving mechanical properties of copper used for electrical conductivity. Cu-B4C composites have been fabricated by powder metallurgy method and sintered at 700C for 2h in open atmosphere and then subjected to cold pressing following sintering process.&nbsp; The presence of Cu and B4C which are dominant components in the sintered composites were confirmed by X-ray diffraction analyses technique and SEM-EDS.&nbsp; Scanning electron microscope (SEM-EDS) was showed that B4C particles are distributed homogenously in the copper matrix. The relative densities of Cu and Cu-B4C composites sintered at 700&deg;C are ranged from 97.5% to 90.19%. Microhardness of composites ranged from 80.65 to 87.5 HB and the electrical conductivity of composites changed between 90.04 %IACS and 68.87 %IACS. It was observed that cold pressed Cu - 1 wt.% B4C composites revealed promising physical properties

Cognitive performance of primary open-angle glaucoma and normal-tension glaucoma patients

ABSTRACT Purpose: To assess cognitive performance differences among primary open-angle glaucoma (POAG) patients, normal-tension glaucoma (NTG) patients, and healthy control (C) subjects. Methods: A total of 60 participants (20 POAG, 20 NTG, and 20 C subjects) were included in this study. A detailed ophthalmologic examination was performed on all participants. A spectral domain-optical coherence tomography (SD-OCT) system was used to measure the ganglion cell-inner plexiform layer (GC-IPL) and retinal nerve fiber layer (RNFL) thicknesses. To assess the cognitive performance of all participants, detailed neurological examinations, including the mini-mental state examination (MMSE), were performed by the same neurologist. Results: There were no significant differences among the groups in terms of age (p =0.348) or gender (p =0.935). The mean RNFL thicknesses were significantly different among the groups (85.2 ± 14.7, 76.8 ± 10.3, and 91.4 ± 7.7 µm in the POAG, NTG, and C subjects, respectively; p <0.001). The mean GC-IPL thicknesses were 77.5 ± 9.7 µm in the POAG group, 73.4 ± 7.8 µm in the NTG group, and 78.8 ± 3.8 µm in the C group. Differences among the groups were not statistically significant (p =0.085). MMSE scores were 26.1 ± 1.4, 25.7 ± 2.3, and 28.8 ± 0.9 in the POAG, NTG, and C groups, respectively. There were significant differences among the three groups (p <0.001). Specifically, there were significant differences between the NTG and C groups (p <0.001), and between the POAG and C groups (p =0.001). There was no significant difference between the POAG and NTG groups (p =0.595). Conclusions: There appear to be similar risk factors in glaucoma and neurodegenerative disorders that cause deterioration in cognitive performance. Comparing the low MMSE scores of the POAG and NTG patients with the scores of healthy C participants supports our hypothesis. Consequently, it is recommended that a neurologist should also examine glaucoma patients

Examining the postural awareness and flexibility changes in physical therapy students who took clinical Pilates class

WOS: 000406648700025PubMed ID: 28811786Objective: This study aimed to evaluate postural awareness and changes in posture and flexibility of students who took Clinical Pilates class as an elective course at the undergraduate level. Methods: The study conducted from 2013-2016 included 98 students who took Clinical Pilates class at the Department of Physical Therapy and Rehabilitation, School of Health Sciences, Istanbul Medipol University, Turkey. The flexibility levels of the study participants were measured before and after the Clinical Pilates education using finger-to-floor test and modified Schober's test. Observational posture analysis and postural awareness were recorded using the scale prepared by the researchers. Results: The post-education evaluations showed that postural distortions were fixed, and a significant increase in the postural awareness of the students was observed compared with the pre-education period. The results of both modified Schober's test and finger-to-floor test, which were used to measure the flexibility levels, showed a statistically significant increase in post-education scores compared with those of the pre-education period. Conclusion: This study showed that the Clinical Pilates course increased postural awareness and flexibility of physical therapy students and fixed postural distortions. Thus, the inclusion of Clinical Pilates class in the undergraduate education is considered to be important

Hemşirelik Bölümü Öğrencilerinin HIV/AIDS’e ilişkin Bilgi Düzeyleri: İstanbul, Ağrı ve Mersin Örneği

Ama&ccedil;: Bu araflt&rsaquo;rma, T&uuml;rkiye&rsquo;nin &uuml;&ccedil; farkl&rsaquo; b&ouml;lgesinde yer alan &uuml;&ccedil; farkl&rsaquo; flehirde &ouml;&curren;renim g&ouml;ren hemflirelik b&ouml;l&uuml;m&uuml; &ouml;&curren;rencilerinin HIV/AIDS ile ilgili bilgi d&uuml;zeylerini belirlemek amac&rsaquo;yla yap&rsaquo;lm&rsaquo;flt&rsaquo;r. Y&ouml;ntem: &Uuml;&ccedil; farkl&rsaquo; &uuml;niversitenin hemflirelik b&ouml;l&uuml;m&uuml;nde &ouml;&curren;renim g&ouml;ren ve tabakal&rsaquo; &ouml;rneklem y&ouml;ntemi ile se&ccedil;ilen 226 &ouml;&curren;renciye, araflt&rsaquo;rmac&rsaquo;lar taraf&rsaquo;ndan oluflturulmufl Kiflisel Bilgi Formu ve HIV/AIDS Bilgi Formu uygulanm&rsaquo;flt&rsaquo;r. Bulgular: Araflt&rsaquo;rmaya kat&rsaquo;lan &ouml;&curren;rencilerden 220&rsquo;sinin (%97.3) bekar oldu&curren;u; 213 &ouml;&curren;rencinin ise (%94.2) daha &ouml;nce hi&ccedil; cinsel iliflki deneyimi olmad&rsaquo;&curren;&rsaquo; belirlenmifltir. &Ouml;&curren;rencilerin %42.9&rsquo;u HIV/AIDS&rsquo;le ilgili ilk bilgilerini TV arac&rsaquo;l&rsaquo;&curren;&rsaquo;yla &ouml;&curren;rendi&curren;ini belirtirken, %25.2&rsquo;si lisedeki e&curren;itimcilerden, %13.3&rsquo;&uuml; &uuml;niversitedeki e&curren;itimcilerden, %12.0&rsquo;&rsaquo; aileleri veya arkadafllar&rsaquo; arac&rsaquo;l&rsaquo;&curren;&rsaquo;yla ve %6.2&rsquo;si ise kitap, internet vb. arac&rsaquo;- l&rsaquo;&curren;&rsaquo;yla &ouml;&curren;rendi&curren;ini ifade etmifltir. Bulgular, &ouml;&curren;rencilerin HIV/AIDS Bilgi Formu&rsquo;nu b&uuml;y&uuml;k oranda do&curren;ru cevaplamalar&rsaquo;na ra&curren;men, yine de hastal&rsaquo;&curren;&rsaquo;n bulaflmas&rsaquo; hakk&rsaquo; nda eksik ya da yanl&rsaquo;fl bilgilerinin oldu&curren;u g&ouml;stermektedir. Araflt&rsaquo;rmada, &ouml;&curren;rencilerin HIV/AIDS konusundaki bilgi d&uuml;zeyleri y&uuml;ksek bulunmufltur. &Ouml;&curren;rencilerin s&rsaquo;n&rsaquo;f d&uuml;zeyleri y&uuml;kseldik&ccedil;e bilgi puan ortalamalar&rsaquo; da artmaktad&rsaquo;r. Farkl&rsaquo; &uuml;niversitelerde e&curren;itim alan &ouml;&curren;rencilerin bilgi puan ortalamalar&rsaquo; birbirinden farkl&rsaquo;d&rsaquo;r. Araflt&rsaquo;rmada, farkl&rsaquo; &uuml;niversitelerin farkl&rsaquo; s&rsaquo;n&rsaquo;flar&rsaquo; aras&rsaquo;ndaki farkl&rsaquo;l&rsaquo;k incelendi&curren;inde, A&curren;r&rsaquo; Da&curren;&rsaquo; ve Mersin &Uuml;niversitesi sa&curren;l&rsaquo;k y&uuml;ksekokulu &ouml;&curren;rencilerinin s&rsaquo;n&rsaquo;f d&uuml;zeyi artt&rsaquo;k&ccedil;a puan ortalamalar&rsaquo; da artmakta iken, &lsaquo;stanbul &Uuml;niversitesi Bak&rsaquo;rk&ouml;y Sa&curren;l&rsaquo;k Y&uuml;ksekokulu birinci s&rsaquo;n&rsaquo;f &ouml;&curren;rencilerinin bilgi puan ortalamas&rsaquo; ikinci s&rsaquo;n&rsaquo;f &ouml;&curren;rencilerin ortalamas&rsaquo;ndan daha y&uuml;ksektir. Tart&rsaquo;flma: Gen&ccedil;lerin HIV/AIDS konusunda birincil bilgi kayna&curren;&rsaquo; olarak televizyonu belirtmeleri bu konuda yap&rsaquo;lm&rsaquo;fl di&curren;er araflt&rsaquo;rma bulgular&rsaquo; ile paraleldir. HIV/AIDS&rsquo;in bulaflma ve korunma yollar&rsaquo; konusunda gen&ccedil;lerin bilgi sahibi olmas&rsaquo;, hastal&rsaquo;&curren;&rsaquo;n h&rsaquo;zla yay&rsaquo;lmas&rsaquo;n&rsaquo; engellemekle birlikte, HIV/AIDS hakk&rsaquo;nda yanl&rsaquo;fl inan&ccedil;lar&rsaquo; n ve eksik bilgilerin giderilmesini sa&curren;layacaktır

Amoxicillin loaded hollow microparticles in the treatment of osteomyelitis disease using single-nozzle electrospinning

WOS: 000444750500009In this study, hollow microparticles were produced with polymethylsilsesquioxane/chitosan/bovine hydroxyapatite/hexagonalboron nitride (PCBB) polyblend using single-nozzle electrospinning method. Also, hollow microparticles are loaded withamoxicillin (AMX) and their drug delivery capabilities have been studied according to a treatment of osteomyelitis disease.The morphology, chemical groups, particle size, antimicrobial activity, and AMX drug release were systematically studied usingscanning electron microscopy (SEM), optical microscopy, Fourier transformation infrared spectroscopy (FTIR), hollow microparticle size measurements, antimicrobial activity test, and UV spectroscopy. In vitro biocompatibility was analyzed with humanbone osteosarcoma (U2OS) cell line. This present work can help in the design of a drug delivery platform for antimicrobial effectand bone repair at the same time for osteomyelitis disease treatment

Temporal Changes in Linezolid Minimum Inhibitory Concentration Values in Vancomycin-resistant Enterococci and Methicillin-resistant Staphylococcus aureus Strains

WOS: 000511368300006Introduction: Vancomycin-resistant enterococci (VRE) and methicillin-resistant Staphylococcus aureus (MRSA) infections are among the most common Gram-positive nosocomial infections. These isolates are resistant to most antibiotics, limiting the antibiotic options that can be used in treatment and causing treatment failure. Linezolid is an important option in the treatment of resistant Gram-positive infections, and came into use in Turkey in 2006. Linezolid-resistant Enterococci and Staphylococcus strains are rarely reported worldwide. The aim of this study was to investigate whether there was an increase in linezolid minimum inhibitory concentration (MIC) values in VRE and MRSA isolates over time. Materials and Methods: Thirteen VRE and 20 MRSA isolates from 2005-2009 (group 1), 18 VRE and 20 MRSA isolates from 2013-2014 (group 2), and seven VRE and 27 MRSA isolates from 2017-2018 (group 3) obtained from various clinical samples at Kocaeli University Medical Faculty Hospital were included in the study. The linezolid MIC values of the isolates were determined by broth microdilution method. The results were interpreted according to the European Committee on Antimicrobial Susceptibility Testing standards. Results: All of the VRE and MRSA isolates were susceptible to linezolid. Linezolid MIC50 and MIC90 values were 2 mg/l in VRE isolates in all three groups. In MRSA isolates, MIC50 was 2 mg/l in group 1, and 4 mg/l in groups 2 and 3, while MIC90 was 4 mg/l in all groups. Conclusion: Global rates of linezolid resistance has been reported to be <1% for S. aureus and VRE. There were no linezolid-resistant isolates in this study. However, we detected a significant increase in MIC50 and MIC90 values compared to most earlier studies performed in Turkey. This increase is expected due to the widespread use of linezolid over the years. The principles of rational antibiotic use should be applied to maintain the low resistance rates to linezolid, which is one of the few remaining options for the treatment of multidrug-resistant Gram-positive infections