Drop test: A new method to measure the particle adhesion force

Measurement of the adhesive force is of great interest in a large number of applications, such as powder coating and processing of cohesive powders. Established measurement methods such as Atomic Force Microscopy (AFM) and the centrifugal method are costly and time consuming. For engineering applications there is a need to develop a quick test method. The drop test method has been designed and developed for this purpose. In this test method particles that are adhered to a substrate are mounted on and are subjected to a tensile force by impacting the stub against a stopper ring by dropping it from a set height. From the balance of the detachment force and adhesive force for a critical particles size, above which particles are detached and below which they remain on the substrate, the interfacial specific energy is calculated. A model of adhesion is required to estimate the adhesive force between the particles and the surface, and in this work we use the JKR theory. The detachment force is estimated by Newton's second law of motion, using an estimated particle mass, based on its size and density and calculated particle acceleration. A number of materials such as silanised glass beads, Avicel, α-lactose monohydrate and starch have been tested and the adhesive force and energy between the particle and the substrate surface have been quantified. Consistent values of the interface energy with a narrow error band are obtained, independent of the impact velocity. As the latter is varied, different particle sizes detach; nevertheless similar values of the interface energy are obtained, an indication that the technique is robust, as it is in fact based on microscopic observations of many particles. The trends of the results obtained with the drop test method are similar to those shown in studies by other researchers using established methods like the AFM and the centrifuge method

IZNIK NECROPOLIS IN THE LIGHT OF RECENTLY DISCOVERED HYPOGEA

Due to its location at the crossroads of the trade and military routes, Iznik (Nikaia) has been one of the most important cities during the Roman and Byzantine Empires in Anatolia. Even though there have been numerous studies on Iznik (Nikaia), nevertheless the focus of scholarly interest has been mostly on the religious buildings and city walls. The aim of this study is to evaluate a rather neglected part of the city, namely the Late Antique-Early Christian necropolis

THE REUSE OF BYZANTINE SPOLIA IN THE GREEN MOSQUE OF BURSA

Publications on the Green Mosque, built by Sultan Mehmed I the Celebi, mention the use of spolia from the Byzantine period but do not give information on the definition or location of these pieces. Therefore, this paper points out the spolia from the Byzantine period used in the Green Mosque, a well-studied topic in the Ottoman architecture and is well known thanks to its inscriptions, and evaluates the pieces

Examples of Byzantine Ceramoplastic and Polychrome Tile Recently Found at Niksar

The aim of this paper is to introduce the new findings from Niksar dated to the Byzantine period. A small number of striking pieces found in the vicinity of Niksar are currently exhibited in the Yagibasan Madrasah. Among these are quatrefoil ceramoplastic decorations. These decorations were used to adorn building facades in Byzantine architecture. Their analogs are seen in the Balkans, Constantinopolis (capital of the Byzantine Empire), and Western Anatolia

Long term results of free flaps in facial contour restoration

Facial defects can be reconstructed by utilization of free tissue transfers. This can be the result of a congenital, post-traumatic, post-radiotherapy or post-surgical condition. Microsurgical reconstruction techniques enable one stage correction. We have utilized various free flaps (omentum 4, serratus anterior muscle Rap 3, scapular flap 4 and groin flap 1) for facial contour restoration in 12 patients who had tissue deficits because of Romberg's disease, hemifacial microsomia, hypoplasia due to radiotherapy, tumor resection and post trauma. All vessel anastomosis were performed by the second author. No flap was lost. In conclusion, late descent of omentum, muscle and dermal fat tissue could not be prevented, whereas there was relatively minimal sagging of scapular tissue, therefore multiple flap revisions were performed in all patients in the long term

Liver resection modulates hepatic chemokine levels in breast cancer

BACKGROUND: Resection of metastatic hepatic tumors of breast cancer may result in the acceleration of hepatic and extrahepatic tumor progression due to the microenvironmental circulation of chemokines. This study aimed to investigate the effect of hepatectomy on a large panel of chemokines, liver regeneration, and myeloid cell levels in an experimental breast cancer model. METHODS: The 4T1 breast cancer cells were inoculated, and 30% to 40% hepatectomy was performed. Mice without tumors or only laparotomy (no hepatectomy) served as control groups. After 14 days (short-term) and 21 days (long-term), tissue samples were obtained from the regions near and distant from the resection site. Chemokine levels were evaluated by enzyme-linked immunosorbent assay arrays. Myeloid infiltration in the liver and the primary tumor and hepatic regeneration status were also histopathologically evaluated. RESULTS: The levels of pro-tumorigenic chemokines such as CCL2, CCL3, CCL4, and CCL5 were elevated in hepatectomized tumor-bearing animals. This observation was consistent with the presence of hepatic metastases. Liver regeneration and myeloid cell infiltration showed significant differences between the tumor-bearing hepatectomized groups followed in the short and long term. CONCLUSION: Our study showed elevation and variations in chemokines after hepatectomy, with a prominent increase in pro-tumorigenic chemokines. These results can be associated with the acceleration of metastasis after liver resection. However, further prospective studies are required to better define the impact of resection, which may transform the liver into a favorable site for metastasis

Evaluation of serum Vitamin B12 level and related nutritional status among apparently healthy obese female individuals

Objective: Obesity is a major public health problem and great risk for not only cardiovascular diseases but also cancer, musculoskeletal, and gynecological diseases. This study was aimed to investigate the association between serum Vitamin B12 (vitB12), body mass index (BMI), and nutritional status among obese women.Methods: This cross‑sectional study enrolled consecutive female subjects. The consumptions of red meat, fish, bovine liver, egg, and mushroom were recorded. According to the Dietary Reference Intakes, the patients were categorized as insufficiency and sufficiency. Three cutoff points were defined for vitB12 status: (1) Deficiency if vitB12 is <200 pg/mL; (2) insufficiency if vitB12 is 250–350 pg/mL, and (3) sufficient if vitB12 is ≥350 pg/mL. According to BMI, the patients were assigned to nonobese and obese groups. BMI, serum vitB12 level, consumptions of red meat, fish, bovine liver, egg, and mushroom were evaluated and compared between two groups.Results: Mean level of vitB12 was 247.8 ± 10.4 pg/mL and significantly associated with consumption of egg (P = 0.031), bovine liver (P = 0.004), mushroom (P = 0.040), and red meat (P = 0.003). VitB12 was significantly higher in nonobese than obese group (282.5 ± 106.8 vs. 242.5 ± 107.5 pg/mL, P = 0.001). The ratio of vitB12 deficiency was significantly higher in obese than nonobese group (37.6% vs. 24.7%; P = 0.019). VitB12 level was negatively correlated with BMI (r = −0.155; P < 0.001), but not insulin resistance (r = −0.172; P = 0.062).Conclusion: Obesity was associated with low level of vitB12 in obese women, and more likely to be vitB12 deficient. Consumption of certain types of food contributes to increase vitB12 level.Keywords: Body mass index, insulin resistance, nutrition, obesity, Vitamin B1