55 research outputs found

    Clinical and Histopathological Evaluation of Eyelid Lesions: Retrospective Analysis of Tertiary Medical Center Referrals

    Get PDF
    DergiPark: 1020959tmsjAims: To clinically and histopathologically examine eyelid lesions and evaluate the consistency of clinical examination by comparing the provisional diagnoses of patients with their postoperative histopathology results. Methods: In this study, the records of 408 patients who applied to Trakya University, Department of Ophthalmology with an eyelid mass and underwent surgery between January 2000 to November 2019 were retrospectively analyzed. Patients’ data comprised age, gender, location of the mass, lesion distribution according to age and gender, provisional clinical diagnosis of the patients, and histopathological reports. Results: Out of 408 patients, 220 (54%) were female, and 188 (46%) were male. The mean age of the patients was 46.9 ± 20.17 years (range; 5-90 years). In the histopathological examination of the lesions, 318 (77.9%) of them were benign, and 90 (22.1%) of them were malignant. The most common benign lesion was chalazion [112 (35.2%)], while the most common malignant lesion was basal cell carcinoma [71 (78.9%)]. The clinical pre-diagnosis and histopathological di- agnosis were found to be compatible in 81 (90%) patients with a malignant lesion. There was a statistically significant difference in age between malignant and benign lesions, where malignant lesions were found more in older patients. The histopathological examination ended up being malignant in 2.2% of the lesions with a benign provisional diagnosis. Conclusion: In conclusion, even though most common eyelid lesions in our study were found to be benign, some lesions diagnosed as benign in clinic were found to be malignant after histopathological examination. Hence all excisions should be evaluated histopathologically to achieve a better clinical outcome in all patients with an eyelid lesion

    Magnetic phase separation in microgravity

    Get PDF
    The absence of strong buoyancy forces severely complicates the management of multiphase flows in microgravity. Different types of space systems, ranging from in-space propulsion to life support, are negatively impacted by this effect. Multiple approaches have been developed to achieve phase separation in microgravity, whereas they usually lack the robustness, efficiency, or stability that is desirable in most applications. Complementary to existing methods, the use of magnetic polarization has been recently proposed to passively induce phase separation in electrolytic cells and other two-phase flow devices. This article illustrates the dia- and paramagnetic phase separation mechanism on MilliQ water, an aqueous MnSO4 solution, lysogeny broth, and olive oil using air bubbles in a series of drop tower experiments. Expressions for the magnetic terminal bubble velocity are derived and validated and several wall–bubble and multi-bubble magnetic interactions are reported. Ultimately, the analysis demonstrates the feasibility of the dia- and paramagnetic phase separation approach, providing a key advancement for the development of future space systems

    application of surface transformation films and nanosphere lithography

    Get PDF
    Photoelectrochemical (PEC) cells offer the possibility of carbon-neutral solar fuel production through artificial photosynthesis. The pursued design involves technologically advanced III–V semiconductor absorbers coupled via an interfacial film to an electrocatalyst layer. These systems have been prepared by in situ surface transformations in electrochemical environments. High activity nanostructured electrocatalysts are required for an efficiently operating cell, optimized in their optical and electrical properties. We demonstrate that shadow nanosphere lithography (SNL) is an auspicious tool to systematically create three-dimensional electrocatalyst nanostructures on the semiconductor photoelectrode through controlling their morphology and optical properties. First results are demonstrated by means of the photoelectrochemical production of hydrogen on p-type InP photocathodes where hitherto applied photoelectrodeposition and SNL-deposited Rh electrocatalysts are compared based on their J–V and spectroscopic behavior. We show that smaller polystyrene particle masks achieve higher defect nanostructures of rhodium on the photoelectrode which leads to a higher catalytic activity and larger short circuit currents. Structural analyses including HRSEM and the analysis of the photoelectrode surface composition by using photoelectron spectroscopy support and complement the photoelectrochemical observations. The optical performance is further compared to theoretical models of the nanostructured photoelectrodes on light scattering and propagation

    Magnetic phase separation in microgravity

    Get PDF
    The absence of strong buoyancy forces severely complicates the management of multiphase flows in microgravity. Different types of space systems, ranging from in-space propulsion to life support, are negatively impacted by this effect. Multiple approaches have been developed to achieve phase separation in microgravity, whereas they usually lack the robustness, efficiency, or stability that is desirable in most applications. Complementary to existing methods, the use of magnetic polarization has been recently proposed to passively induce phase separation in electrolytic cells and other two-phase flow devices. This article illustrates the dia- and paramagnetic phase separation mechanism on MilliQ water, an aqueous MnSO4 solution, lysogeny broth, and olive oil using air bubbles in a series of drop tower experiments. Expressions for the magnetic terminal bubble velocity are derived and validated and several wall–bubble and multi-bubble magnetic interactions are reported. Ultimately, the analysis demonstrates the feasibility of the dia- and paramagnetic phase separation approach, providing a key advancement for the development of future space systems

    Releasing the Bubbles: Nanotopographical Electrocatalyst Design for Efficient Photoelectrochemical Hydrogen Production in Microgravity Environment

    Get PDF
    Photoelectrochemical devices integrate the processes of light absorption, charge separation, and catalysis for chemical synthesis. The monolithic design is interesting for space applications, where weight and volume constraints predominate. Hindered gas bubble desorption and the lack of macroconvection processes in reduced gravitation, however, limit its application in space. Physico-chemical modifications of the electrode surface are required to induce gas bubble desorption and ensure continuous device operation. A detailed investigation of the electrocatalyst nanostructure design for light-assisted hydrogen production in microgravity environment is described. p-InP coated with a rhodium (Rh) electrocatalyst layer fabricated by shadow nanosphere lithography is used as a model device. Rh is deposited via physical vapor deposition (PVD) or photoelectrodeposition through a mask of polystyrene (PS) particles. It is observed that the PS sphere size and electrocatalyst deposition technique alter the electrode surface wettability significantly, controlling hydrogen gas bubble detachment and photocurrent–voltage characteristics. The highest, most stable current density of 37.8 mA cm−2 is achieved by depositing Rh via PVD through 784 nm sized PS particles. The increased hydrophilicity of the photoelectrode results in small gas bubble contact angles and weak frictional forces at the solid–gas interface which cause enhanced gas bubble detachment and enhanced device efficiency

    Efficient solar hydrogen generation in microgravity environment

    Get PDF
    Long-term space missions require extra-terrestrial production of storable, renewable energy. Hydrogen is ascribed a crucial role for transportation, electrical power and oxygen generation. We demonstrate in a series of drop tower experiments that efficient direct hydrogen production can be realized photoelectrochemically in microgravity environment, providing an alternative route to existing life support technologies for space travel. The photoelectrochemical cell consists of an integrated catalyst-functionalized semiconductor system that generates hydrogen with current densities >15 mA/cm2 in the absence of buoyancy. Conditions are described adverting the resulting formation of ion transport blocking froth layers on the photoelectrodes. The current limiting factors were overcome by controlling the micro- and nanotopography of the Rh electrocatalyst using shadow nanosphere lithography. The behaviour of the applied system in terrestrial and microgravity environment is simulated using a kinetic transport model. Differences observed for varied catalyst topography are elucidated, enabling future photoelectrode designs for use in reduced gravity environments

    Releasing the bubbles : nanotopographical electrocatalyst design for efficient photoelectrochemical hydrogen production in microgravity environment

    Get PDF
    Photoelectrochemical devices integrate the processes of light absorption, charge separation, and catalysis for chemical synthesis. The monolithic design is interesting for space applications, where weight and volume constraints predominate. Hindered gas bubble desorption and the lack of macroconvection processes in reduced gravitation, however, limit its application in space. Physico‐chemical modifications of the electrode surface are required to induce gas bubble desorption and ensure continuous device operation. A detailed investigation of the electrocatalyst nanostructure design for light‐assisted hydrogen production in microgravity environment is described. p‐InP coated with a rhodium (Rh) electrocatalyst layer fabricated by shadow nanosphere lithography is used as a model device. Rh is deposited via physical vapor deposition (PVD) or photoelectrodeposition through a mask of polystyrene (PS) particles. It is observed that the PS sphere size and electrocatalyst deposition technique alter the electrode surface wettability significantly, controlling hydrogen gas bubble detachment and photocurrent–voltage characteristics. The highest, most stable current density of 37.8 mA cm−2 is achieved by depositing Rh via PVD through 784 nm sized PS particles. The increased hydrophilicity of the photoelectrode results in small gas bubble contact angles and weak frictional forces at the solid–gas interface which cause enhanced gas bubble detachment and enhanced device efficiency

    Preoperative MELD-Na Score Predicts 30-day Post-operative Complications After Colorectal Resection for Malignancy

    Get PDF
    Introduction:Predicting possible complications in colon surgery is important in terms of reducing postoperative mortality and morbidity rates. Various scoring methods have been used to predict these complications. The MELD score was developed to predict mortality following Transjugular Intrahepatic Portosystemic Shunt (TIPS) placement in cirrhotic patients. This model was revised by adding Na data and used to predict complications in non-cirrhotic patients. We investigated the value of the MELD-Na score in predicting postoperative 30-day complications in patients undergoing colorectal resection for malignancy.Methods:Patients who underwent colorectal resection for malignant diseases were included in the study. Demographics and clinical outcomes were recorded. The MELD-Na scores of the patients were calculated within 48 h before the surgery. Patients were divided into 2 groups according to the status of development of any complication.Results:Age, gender, operative time, and length of stay was not statistically significant for developing complications. The MELD-Na score was significantly higher in patients with any complications. Also, MELD-NA score, stoma creation, and postoperative erythrocyte suspension replacement were found to be independent risk factors for developing complications in patients undergoing surgery for colon cancer.Conclusion:The MELD-Na score may predict the complications that may develop in the first 30 days postoperatively in patients undergoing colorectal resection for malignant diseases

    The effect of post-wildfire management practices on vegetation recovery: Insights from the Sapadere fire, Antalya, TĂŒrkiye

    Get PDF
    Post-wildfire management actions mainly targeting the removal of salvage logs and burned trees is a common but controversial practice. Although it aims to regain some of the natural and economic value of a forest, it also requires disturbing burned areas, which may have some negative consequences affecting, for instance, the carbon cycle, soil erosion, and vegetation cover. Observations from different geographic settings contribute to this scientific debate, and yet, the spatiotemporal evolution of the post-fire road network developed as part of fire management practices and its influence on vegetation recovery has been rarely examined. Specifically, we still lack observations from TĂŒrkiye, though wildfires are a common event. This research examined the evolution of the vegetation cover in relation to post-fire road constructions and the resultant debris materials in areas affected by the 2017 Sapadere fire in Antalya, TĂŒrkiye. We used multi-sensor, multi-temporal optical satellite data and monitored the variation in both vegetation cover and road network from the pre-to post-fire periods between 2014 and 2021. Our results showed that fire management practices almost doubled the road network in the post-fire period, from 487 km to 900 km. Overall, 7% of the burned area was affected by these practices. As a result, vegetation cover in those areas shows only ∌50% recovery, whereas undisturbed areas exhibit ∌100% recovery 5 years after the event. Notably, such spatiotemporal analysis carried out for different burned areas would provide a better insight into the most suitable post-fire management practices. Our findings, in particular, show that the current practices need to be revisited as they cause a delay in vegetation recovery

    Electrolysis in reduced gravitational environments: current research perspectives and future applications

    Get PDF
    Electrochemical energy conversion technologies play a crucial role in space missions, for example, in the Environmental Control and Life Support System (ECLSS) on the International Space Station (ISS). They are also vitally important for future long-term space travel for oxygen, fuel and chemical production, where a re-supply of resources from Earth is not possible. Here, we provide an overview of currently existing electrolytic energy conversion technologies for space applications such as proton exchange membrane (PEM) and alkaline electrolyzer systems. We discuss the governing interfacial processes in these devices influenced by reduced gravitation and provide an outlook on future applications of electrolysis systems in, e.g., in-situ resource utilization (ISRU) technologies. A perspective of computational modelling to predict the impact of the reduced gravitational environment on governing electrochemical processes is also discussed and experimental suggestions to better understand efficiency-impacting processes such as gas bubble formation and detachment in reduced gravitational environments are outlined
    • 

    corecore