Utjecaj nanočestica cinkova oksida na vatrootpornost drvno-plastičnih kompozita

The interest in wood plastic composites (WPCs) has increased in recent years. The utilization of environmentally friendly materials has been of great significance due to the overwhelming pressure on nature. As a widely used material, plastic is, however, easily combustible due to its structure. In this study, WPCs were reinforced with zinc oxide (ZnO) nanoparticles. The effect of higher content of ZnO nanoparticles (1, 3, 5, 10 %) on WPCs thermal stability and fire performance was investigated. Thermogravimetric analysis (TGA) clearly demonstrated that nanoparticles acted as a shield, which inhibited heat transfer and increased the degradation temperature thanks to covering the surface of materials. Free radicals accelerated the thermal degradation of neat-HDPE (high-density polyethylene) by oxidative reactions, while ZnO nanoparticles reduced the degradation velocity. Moreover, the increase in nanoparticle content significantly affected the residue. The fire performance of WPCs was also investigated by the limit oxygen index (LOI) test. While neat-HDPE flamed with dripping, ZnO nanoparticles made flaming difficult for WPCs. Therefore, the LOI values increased with increasing nanoparticle content up to 28.5 %, which indicated the need for more oxygen. The improvement reached up to 54 % compared to neat HDPE. Moreover, the char forming was also improved, which helped enhance the fire resistance. The scanning electron microscope (SEM) investigation indicated that nanoparticles were well dispersed in the matrix. However, the tendency to agglomerate increased with the increase of concentration. The ability of carbonization of wood fiber surface during the combustion also contributed to improving thermal stability and fire performance.Zanimanje za drvno-plastične kompozite (WPC) posljednjih je godina poraslo. Upotreba ekološki prihvatljivih materijala ima veliko značenje zbog golemog pritiska na okoliš. Plastika je široko rasprostranjen i vrlo često upotrebljavan materijal, ali je zbog svoje strukture lako zapaljiva. U ovom su istraživanju drvno-plastični kompoziti ojačani nanočesticama ZnO. Istraživan je utjecaj većeg udjela nanočestica cinkova oksida (ZnO) (1, 3, 5 i 10 %) na toplinsku stabilnost i vatrootpornost WPC-a. Termogravimetrijska analiza (TGA) jasno je pokazala da nanočestice djeluju kao štit koji inhibira prijenos topline i povećava temperaturu razgradnje. Nadalje, slobodni radikali u reakcijama oksidacije ubrzali su toplinsku razgradnju čistog HDPE-a (polietilena visoke gustoće), dok su nanočestice ZnO smanjile brzinu razgradnje. Štoviše, povećanje udjela nanočestica znatno je utjecalo na ostatak nakon razgradnje. Vatrootpornost WPC-a također je ispitana mjerenjem graničnog indeksa kisika (LOI). Dok je čisti HDPE gorio uz kapanje, nanočestice ZnO otežale su gorenje WPC-a. LOI vrijednosti rasle su s povećanjem udjela nanočestica do 28,5 %, što je upućivalo na veću potrebu za kisikom. Poboljšanje je iznosilo do 54 % u usporedbi s čistim HDPE-om. Štoviše, poboljšano je i stvaranje pougljenjenog sloja koji je pridonio povećanju vatrootpornosti. Istraživanje pretražnim elektronskim mikroskopom (SEM) pokazalo je da su se nanočestice dobro dispergirale u matrici. Međutim, tendencija aglomeraciji povećala se s povećanjem koncentracije nanočestica. Sposobnost karbonizacije površine drvnih vlakanaca tijekom gorenja također je pridonijela poboljšanju toplinske stabilnosti i vatrootpornosti WPC-a

EVALUATION OF THE IMPACTS OF SURGICAL REMOVAL OF IMPACTED TEETH ON ALTERATIONS OF THE MOOD WITH BECK DEPRESSION INVENTORY

Objectives To determine whether the inflammatory complications following impacted third molar surgeries and varying surgical difficulties impact individuals' mood alterations. Materials and Methods A prospective, double-blind, observational study was designed with three study groups (slightly, moderate, and very difficult) constituted with surgical difficulty scores. The participants were evaluated preoperatively and postoperatively on the sixth hour, second and seventh days. The visual analog scale (VAS) and Beck depression scale (BDS) scores, maximal mouth opening, and swelling amounts were recorded. Results A total of 75 patients were enrolled and divided into three study groups with an equal number of participants. The preoperative mean BDS scores of the study groups (slightly, moderate, very difficult) were 9.16, 7.16, and 8.12, and mean VAS scores were 2.86, 1.4, and 1.56, respectively. A significant correlation was observed between the surgical difficulty and the increased BDS scores on the second and seventh postoperative days (p=0.031, p=0.001). Significant correlations were observed between surgical difficulty and VAS scores (p=0.018) and maximum mouth opening amounts (p=0.021) on the second postoperative day. Also, postoperative swelling amounts were significantly affected by surgical difficulty on the postoperative second day (p=0.007). The impact of surgical difficulty and inflammatory complication-related factors on the postoperative BDS scores' increase was also evaluated, and the postoperative pain, trismus, swelling, and operation time correlated. Conclusion The surgical removal of impacted molar teeth has significant effects on alterations in mood. It would be beneficial to consider different aspects of the postoperative term that the patient will experience in third molar surgeries

Isotropic gap formation, localization, and waveguiding in mesoscale Yukawa-potential amorphous structures

Amorphous photonic structures are mesoscopic optical structures described by electrical permittivity distributions with underlying spatial randomness. They offer a unique platform for studying a broad set of electromagnetic phenomena, including transverse Anderson localization, enhanced wave transport, and suppressed diffusion in random media. Despite this, at a more practical level, there is insufficient work on both understanding the nature of optical transport and the conditions conducive to vector-wave localization in these planar structures, as well as their potential applications to photonic nanodevices. In this study, we fill this gap by investigating experimentally and theoretically the characteristics of optical transport in a class of amorphous photonic structures and by demonstrating their use to some basic waveguiding nanostructures. We demonstrate that these 2-D structures have unique isotropic and asymmetric band gaps for in-plane propagation, controlled from first principles by varying the scattering strength and whose properties are elucidated by establishing an analogy between photon and carrier transport in amorphous semiconductors. We further observe Urbach band tails in these random structures and uncover their relation to frequency- and disorder-dependent Anderson-like localized modes through the modified Ioffe-Regel criterion and their mean free path - localization length character. Finally, we illustrate that our amorphous structures can serve as a versatile platform in which photonic devices such as disorder-localized waveguides can be readily implemented.Comment: 9 pages, 4 figure

Effects of systemic Anatolian propolis administration on a rat-irradiated osteoradionecrosis model

Objective: Radiotherapy after head and neck cancer is associated with the risk of osteonecrosis development. This study aims to investigate the effectiveness of systemic propolis application to prevent the disease as it has no definite treatment protocol despite the proposed treatment methods and significantly decreases individuals’ quality of life. Methodology: In total, 29 male Wistar-Albino rats were divided into control, 35 Gy irradiation (Group 1), 35 Gy irradiation+100 mg/kg/ml propolis administration (Group 2), and 35 Gy irradiation+200 mg/kg/ml propolis administration groups (Group 3). Propolis was first applied on the day after radiotherapy, except for the control group. Right first and second molars were extracted from all rats three weeks following radiotherapy. Samples were collected seven weeks after radiotherapy. Osteoblast and osteoclast counts were calculated by histomorphometric analysis. Immunohistochemical analysis determined bone morphogenic protein-2 (BMP-2) and transforming growth factor beta-3 (TGFβ-3). Results: Group comparison found non-significant differences regarding osteoblast (p=0.130) and osteoclast (p=0.063) counts. However, Group 1 showed the lowest mean osteoblast (OBL: 82.63 [±13.10]) and highest mean osteoclast counts (OCL: 12.63 [±5.55]). OBL/OCL ratio showed significant differences between groups (p=0.011). Despite the significant difference between the Control and Groups 1 (p=0.006) and 2 (p=0.029), Group 3 showed a non-significant difference (p=0.091). For BMP-2 and TGFB3, the control group showed significant differences with the other two groups (p<0.001), except for Group 3. Conclusion: Anatolian propolis showed beneficial effects in a radiotherapy-mediated osteonecrosis model, highlighting its potential as a promising intervention

İnferior Alveolar Sinir Lateralizasyonu Sırasında Oluşan Bir Komplikasyon ve Cerrahi Yaklaşım: Vaka Raporu

Alveolar kret tepesi ile inferior alveolar kanal arasında standart boyutlarda dental implant yerleşimi için yeterli kemik yüksekliği bulunmayan bir vakada uygulanan inferior alveolar sinir lateralizasyonu yöntemi sırasında ortaya çıkan bir komplikasyonu tanımlamak, cerrahi, fototerapi ve farmakolojik tedavi yaklaşımlarını güncel veriler ışığında tartışmaktır. Dental implant destekli sabit protetik restorasyon talebi ile başvuran 34 yaşında erkek hastanın implant operasyonu sırasında inferior alveolar sinir lateralizasyonu yapılırken sinir dokusunda transeksiyon meydana gelmiştir. Komplikasyona müdahale amacı ile inferior alveolar sinir transpozisyonu gerçekleştirilmiş ve yaralanma bölgesindeki serbest uçlar pasif olarak bir araya getirilip primer olarak suture edilmiştir. Postoperatif dönemde kortikosteroid ve düşük doz lazer tedavileri uygulanmıştır. Hasta aktif şikayeti bulunmadan takip sürecindedir. Literatürdeki veriler ışığında, dental implant tedavileri için uygulanan ileri cerrahi teknikler arasında inferior alveolar sinir yönelik transpozisyon teknikleri ve ilişkili komplikasyonlar ortaya çıkabilmektedir. Bu teknikler sırasında gerçekleşebilecek ve hastalarda kalıcı sekeller bırakabilecek komplikasyonlardan biri sinir transeksiyonudur. Transeksiyon komplikasyonunda uygulanabilecek primer müdahalelerden biri sinir uçlarının primer olarak yaklaştırılmasıdır. Postoperatif süreçte de iyileşmesinin desteklenmesi için kortikosteroid ve düşük seviye lazer tedavileri önerilmektedir. İnferior alveolar sinire yönelik müdahalelerde detaylı planlama, hassas cerrahi teknikler büyük önem taşısa da sinir yaralanmaları istenmeyen ancak karşılaşılabilecek komplikasyonlardandır. Ancak bu gibi komplikasyonlara müdahale amacı ile erken dönemde nöroenflamasyonu baskılayabilecek ajanlar ve iyileşmeyi destekleyecek tedavi seçenekleri göz önünde tutulmalıdı

EVALUATION OF THE RADIO-PROTECTIVE EFFECTS OF HIGH CAFFEIC ACID PHENYL ESTER CONTAINING PROPOLIS ON RADIOTHERAPY-MEDIATED BUCCAL MUCOSITIS

Aim of the study Lesions such as intraoral buccal mucositis encountered during radiotherapy after head and neck cancers are challenging regarding the prognosis and patient survival. For this purpose, the effectiveness of propolis containing high caffeic acid phenyl ester on buccal mucositis was investigated in a rodent model. Material and methods In the study groups, which comprised nine rats each, radiotherapy (15Gy) was delivered to the head and neck regions. In two of the study groups 100 and 200 mg/kg propolis were administered systemically for 14 days. In the harvested buccal mucosa samples, proinflammatory markers (interleukin-6 [IL-6], myeloperoxidase [MPO], tumor-necrosis factor-α [TNF-α]) were analyzed with Enzyme Linked-Immuno-Sorbent Assay method, and tissue samples were stained with Hematoxylin-eosin and classified regarding the inflammation scores. Results The tissue levels of IL-6, MPO, and TNF-α significantly decreased in a dose-dependent manner in experimental groups (P = 0.001, P = 0.016, P = 0.001, respectively). Also, the inflammation scores were highest in Group 2 (P = 0.002), whereas Groups 3 and 4 had the lowest (P = 0.012). Conclusions Aqueous propolis extract containing high caffeic acid phenyl ester can prevent lesions with its superior anti-inflammatory and free radical scavenging properties. The administration of aqueous propolis containing high caffeic acid phenyl ester decreased the inflammatory responses in a dose-dependent manner