70 research outputs found

    The effect of the process parameters in the planing processes on the surface roughness of cherry and pear woods

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    In this study, the effects of the process parameters in the planing processes on the surface roughness were investigated. For this purpose, the experimental samples of cherry (Prunus avium L.) and pear (Pirus communis L.) wood species, which are commonly used in the Turkish decoration industry, were prepared. In preparing the experimental samples, the wood was planed tangentially and radially to the annual rings at a cutting depth of 1.4 mm in a milling machine with 4 blades 85 mm in diameter. The wood was planed into the direction of spindle rotation and in the direction against the spindle rotation at feed rates of 6, 9 and 12 m/min. The surface roughness values of the experimental samples were determined by using a stylus-type profilometer according to the ISO 4287 standards. The surface roughness was evaluated according to the Ra, Rz and Ry principles, which were three basic parameters of the determination method for surface roughness. According to the results, when the planing parameters were differentiated, the obtained surface roughness values also acquired a different character. The feed direction of work pieces for planing in the direction of spindle rotation was lower than the feed direction in the opposite to spindle rotation for the surface roughness.Keywords: Surface Roughness, Planing, Cherry, Pear

    EFL Learners’ Perceptions of Grammar Knowledge and Grammar Instruction in Foreign Language Learning

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    The position that grammar should hold in L2 learning has been an issue of controversy among scholars and researchers resulting in teaching approaches and methods in which its role has been either overestimated or completely downplayed. Various studies have explored EFL teachers’ beliefs about the role of grammar in L2 learning and their classroom practices. However, very little research has been conducted on the learners’ perceptions regarding grammar knowledge and its instruction in the classroom. This study investigates Albanian EFL learners’ perceptions about the role of grammar knowledge in the language learning process and the learners’ acquisition of the target language. It also explores the learners’ attitudes towards grammar instruction in the classroom and how it affects their proficiency in the target language. 335 male and female high school students who participated in the study were asked to answer questions about the topic. The findings suggest that further research which considers learners’ beliefs will contribute to EFL grammar teaching methods. It might also encourage EFL teachers to reflect upon their beliefs about grammar instruction and employ grammar teaching approaches and classroom practices that do not overlook the learners’ perceptions of grammar and its position in L2 learning.Keywords: EFL learning, learners’ perceptions, grammar knowledge, grammar instruction

    Anatomical and visual outcomes of ranibizumab injections in retinal pigment epithelium tears

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    ABSTRACT Purpose: To report the anatomical and visual results in patients diagnosed as having retinal pigment epithelium (RPE) tears after receiving ranibizumab injections. Methods: Eyes diagnosed as having RPE tears with a minimum 6-month follow-up were retrospectively evaluated. Each eye was treated with at least three doses of ranibizumab at monthly intervals. Best-corrected visual acuity (BCVA), anterior segment findings, intraocular pressure, and fundus examination results were evaluated during control visits. Color fundus photography, fundus fluorescein angiographies, fundus autofluorescence, and spectral domain optical coherence tomography (SD-OCT) images were obtained. The height of pigment epithelial detachment (PED) was measured by SD-OCT. Results: Twelve eyes with RPE tears were studied. Nine eyes (75%) developed RPE tears during ranibizumab injections for choroidal neovascularization (eight eyes with vascularized PED and one eye with choroidal osteoma), and tears occurred in three eyes before any injections. The median number of ranibizumab injections after diagnosis of RPE tears was 3 (min 2, max 5). In the most recent follow-up visit, there was no statistically significant correlation between the grade of RPE and logMAR of BCVA (p>0.05, r=0.112). Eight of twelve eyes had PED, and seven of these had irregular PED contours before injection therapy. The mean PED height was 447 ± 122 ”m. Conclusions: In this series, RPE tears developed mostly after intravitreal anti-VEGF injections for vascularized PED. Increased vertical height and irregular contours of the PEDs can be risk factors for the formation of RPE tears. The continuation of anti-VEGF therapy after tear formation is beneficial for vision improvement in eyes with RPE tears

    Macular Findings Obtained by Spectral Domain Optical Coherence Tomography in Retinopathy of Prematurity

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    Purpose. To examine the macular findings obtained with spectral domain optical coherence tomography (SD OCT) in infants with retinopathy of prematurity (ROP). Materials and Methods. The macular SD OCT images of 190 premature infants were analyzed. Data regarding central foveal thickness (CFT), cystoid macular edema (CME), and cyst grading were compared. The relationships of CFT with gestational age and birth weight were investigated. Results. The results were obtained from 358 eyes of 179 infants (81 females and 98 males) of a mean gestational age of 30.9±2.7 weeks and a mean birth weight of 1609±477 g. ROP was diagnosed in 126 eyes and CME in 139 eyes. A significantly greater percentage of eyes with ROP were found to have CME (54%) compared to eyes without ROP (31%; P=0.001). The incidence of CME was 46.3% for stage 1 ROP, 57.1% for stage 2, and 87.5% for stage 3. There was a weakly inverse correlation between CFT, gestational age, and birth weight (P=0.025, r=-0.227; P=0.002, r=-0.182, resp., Spearman correlation test). Conclusions. High-quality SD OCT images can be obtained from premature infants using the iVue system. Severity and frequency of CME in premature infants increase as stage of ROP increases

    Enhanced Anti-cancer Potency Using a Combination of Oleanolic Acid and Maslinic Acid to Control Treatment Resistance in Breast Cancer

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    Purpose: The phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/ mTOR) pathway is a complex intracellular metabolic pathway that leads to cell growth and tumor proliferation and plays a key role in drug resistance in breast cancer. Therefore, the anti-cancer effects of oleanolic acid (OA), maslinic acid (MA), and their combination were investigated to improve the performance of the treatment strategy. Methods: We investigated the effect of OA and MA on cell viability using the WST-1 method. The synergistic effect of the combination was analyzed by isobologram analysis. In addition, the effects of the two compounds, individually and in combination, on apoptosis, autophagy, and the cell cycle were investigated in MCF7 cells. In addition, changes in the expression of PI3K/AKT/mTOR genes involved in apoptosis, cell cycle and metabolism were determined by quantitative RT-PCR. Results: MA, OA, and a combination of both caused G0/G1 arrest. Apoptosis also increased in all treated groups. The autophagosomal LC3-II formation was induced 1.74-fold in the MA-treated group and 3.25-fold in the MA-OA-treated group. The combination treatment resulted in increased expression of genes such as GSK3B, PTEN, CDKN1B and FOXO3 and decreased expression of IGF1, PRKCB and AKT3 genes. Conclusion: The results showed that the combination of these two substances showed the highest synergistic effect at the lowest dose and using MA-OA caused cancer cells to undergo apoptosis. The use of combination drugs may reduce the resistance of cancer cells to treatment

    MicroRNAs as Targets for Cancer Diagnosis: Interests and Limitations

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    MicroRNAs are small RNAs with ability to attach to the large number of RNA that regulate gene expression on post-transcriptional level via inhibition or degradation of specific mRNAs. MiRNAs in cells are the primary regulators of functions such as cell growth, differentiation, and apoptosis and considerably influence cell function. The expression levels of microRNAs change in human diseases, including cancer. These changes highlight their essential role in cancer pathogenesis. Ubiquitous irregular expression profiles of miRNAs have been detected in various human cancers using genome-wide identification techniques, which are emerging as novel diagnostic and prognostic cancer biomarkers of high specificity and sensitivity. The measurable miRNAs with enhanced stability in blood, tissues, and other body fluids provide a comprehensive source of miRNA-dependent biomarkers for human cancers. The leading role of miRNAs as potential biomarkers in human cancers is discussed in this article. In addition, the interests and difficulties of miRNAs as biomarkers have been explored

    AAPT Diagnostic Criteria for Chronic Sickle Cell Disease Pain

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    Pain in sickle cell disease (SCD) is associated with increased morbidity, mortality, and high health care costs. Although episodic acute pain is the hallmark of this disorder, there is an increasing awareness that chronic pain is part of the pain experience of many older adolescents and adults. A common set of criteria for classifying chronic pain associated with SCD would enhance SCD pain research efforts in epidemiology, pain mechanisms, and clinical trials of pain management interventions, and ultimately improve clinical assessment and management. As part of the collaborative effort between the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks public-private partnership with the U.S. Food and Drug Administration and the American Pain Society, the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks-American Pain Society Pain Taxonomy initiative developed the outline of an optimal diagnostic system for chronic pain conditions. Subsequently, a working group of experts in SCD pain was convened to generate core diagnostic criteria for chronic pain associated with SCD. The working group synthesized available literature to provide evidence for the dimensions of this disease-specific pain taxonomy. A single pain condition labeled chronic SCD pain was derived with 3 modifiers reflecting different clinical features. Future systematic research is needed to evaluate the feasibility, validity, and reliability of these criteria. Perspective: An evidence-based classification system for chronic SCD pain was constructed for the Analgesic, Anesthetic, and Addiction Clinical Trial Translations Innovations Opportunities and Networks-American Pain Society Pain Taxonomy initiative. Applying this taxonomy may improve assessment and management of SCD pain and accelerate research on epidemiology, mechanisms, and treatments for chronic SCD pain

    Thinking beyond sickling to better understand pain in sickle cell disease

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    Painful vaso‐occlusive crises ( VOC s) are the hallmark of sickle cell disease ( SCD ); however, many patients experience frequent daily pain that does not follow the pattern of typical VOC s. This pain of variable severity, also referred as persistent pain in the SCD literature, contributes to significant morbidity and poor quality of life and often fails to respond adequately to standard SCD therapies. In this article, we briefly describe types of pain encountered in SCD with a special emphasis on persistent pain. We discuss altered pain processing as a potential contributing mechanism, which may lead to development and maintenance of persistent pain. We describe the advances in the non‐ SCD pain field that may help improve the understanding of SCD pain. We highlight the need for further investigation in this area because some of these patients with persistent pain may benefit from receiving adjuvant mechanism‐based therapies used successfully in other non‐ SCD chronic pain conditions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/108028/1/ejh12340.pd

    Determination of the Effect of Surface Roughness on the Bonding Strength of Wooden Materials

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    The purpose of this study was to determine the effect of surface roughness on bonding strength in Oriental beech, cherry, Scots pine, and Taurus cedar woods. In conformance with this objective, after planing the wooden materials under different conditions, their surface roughness values were determined in accordance with various standards using scanning equipment. The bonding strength test specimens were prepared using polyvinyl acetate (PVAc) and polyurethane (PUR) adhesives after the wooden materials were separated into three groups of varying surface roughness values, after which bonding strength experiments were carried out. The data obtained from the experiments were evaluated statistically at a 95% level of confidence. According to the test results, the highest bonding strength was obtained in the Oriental beech (9.27 N/mm2), whereas the lowest bonding strength was obtained in the Scots pine (3.65 N/mm2). There was not a statistically significant difference between the bonding strength of the cherry and Oriental beech woods. The PVAc adhesive (7.61 N/mm2) produced more successful results than the PUR adhesive (5.63 N/mm2). Furthermore, it was found that in the specimens with low surface roughness values for each wood type and used adhesives had high bonding strengths
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