Surface charging and current collapse in an AlGaN∕GaN heterostructure field effect transistor

This work investigates the correlation between surfacecharging and current collapse in an AlGaN∕GaNheterostructurefield effect transistor.Surfacecharging due to applied biases was sensed by mapping the surface potential between the gate and drain using scanning Kelvin probe microscopy. Due to the bias, the surface band bending near the gate edge was observed to increase by as much as 1 eV. This increase of band bending is caused by an accumulation of excess charge near the surface during the applied bias. By varying the duration of the applied bias, we find that this accumulation of excess charge near the gate takes about 20 s to saturate. Continuous monitoring of the surface potential after switching off the bias shows that a complete relaxation of the excess band bending requires about 800 s. Drain current transient measurements show that the collapse and recovery of the drain current also occur on similar time scales. This correlation between time scales indicates that the accumulation of excess charge near the gate edge causes current collapse by depletion of the channel

Pazarlamanın Şirketlerin İş Performansı Üzerindeki Etkisi: Bir Literatür Taraması

The technology-based global competition environment that pushes businesses to constructive transformation in order to ensure customer satisfaction has further increased the importance of marketing capabilities in business strategies. The purpose of the literature review is to summarize the previous studies about marketing-financial performance nexus. Studies that were published between 1969 and 2019 could be reached from the EBSCO database were included in the literature review. A significant number of studies conducted in different countries have shown that marketing spending is an investment that creates value for the company and has a positive impact on firm profitability, firm value or firm sales. This study contributes to the literature by summarizing the research findings on the effects of marketing investments on business performance.TR - Dizi

A computed tomography-based morphometric study of the styloid process

Background: The styloid process (SP) refers to a cylindrical piece projecting from the inferior of the temporal bone, situated anterior to the stylomastoid foramen. It is an anatomic formation close to major vessels and nerves, and its excessive elongation results in pathologies leading to anatomical disorders, such as Eagle’s syndrome. Several studies have been conducted on SP in relation to its close proximity to vessels and nerves, but there is no study that reveals its distance to important anatomical formations, such as the internal auditory meatus (IAM), carotid canal (CC), cochlea, tegmen tympani (TT) and tragus. In the current study, we aimed to investigate the incidence of Eagle’s syndrome based on morphometric measurements of SP. Materials and methods: The patient files archived in the Radiology Department of Adiyaman University Training and Research Hospital were retrospectively examined. The study was carried out on the data of patients for whom specialist radiologists found no pathology findings on the computed tomography images. A total of 77 individuals (36 females and 41 males) aged 22 to 54 years were included in the study. The length of SP and its distances to IAM, cochlea, CC, TT and tragus were obtained using computed tomography radiological measurements. Results: When the individual measurements performed on computed tomography images were evaluated in men and women, no significant difference was found concerning the distance between SP and various anatomic structures in close proximity to SP (p > 0.05). However, there was a statistically significant difference between the genders in length of the right SP (p = 0.003) and left SP (p = 0.006). Conclusions: This anthropometric study revealed the standard morphometric measurements of SP. We believe that the data obtained will help clinicians to identify and diagnose pathologies more easily

Soft Bottom Molluscan Assemblages of the Bathyal Zone of the Sea of Marmara

The present study deals with the soft bottom molluscan species collected from the bathyal zone of the Sea of Marmara in 2013. Replicated samples were taken by a Box Core, sampling an area of 0.1 m2 at 31 stations at the two depth transects, 500 and 1000 m. A total of 1229 individuals belonging to 4 classes and 28 species were collected. Two species (Akritogyra conspicua and Liostomia hansgei) are new records for the marine molluscan fauna of Turkey and four species (Benthonella tenella, Odostomia silesui, Syrnola minuta and Crenilabium exile) are new records for the molluscan fauna of the Sea of Marmara. A relatively richer fauna was determined in 500 m (25 species) than in 1000 m (17 species). The most dominant species at 500 m and 1000 m depths were Crenilabium exile and Parthenina flexuosa, respectively. Number of species and number of individuals varied significantly only between depths while number of individuals changed significantly among basins (ANOVA test). A significant difference in species assemblages between the Tekirdağ and the Central Basins was detected (ANOSIM test). The multivariate analysis showed that the depth was the main factor influencing the molluscan assemblages in the area

Xanthogranulomatous Endometritis: A Challenging Imitator of Endometrial Carcinoma

Xanthogranulomatous inflammation is a distinguished histopathological entity affecting several organs, predominantly the kidney and gallbladder. So far, only a small number of cases of xanthogranulomatous inflammation occurring in female genital tract have been described, most frequently affecting the endometrium and histologically characterized by replacement of endometrium by xanthogranulomatous inflammation composed of abundant foamy histiocytes, siderophages, giant cells, fibrosis, calcification and accompanying polymorphonuclear leucocytes, plasma cells and lymphocytes of polyclonal origin. We present a case of a 69-year-old female complained of post menopausal bleeding and weight loss. Clinical preliminary diagnoses were endometrial carcinoma or hyperplasia and ultrasound was supposed to be endometrial malignancy, hyperplasia or pyometra by radiologist. Histopathological examination of uterus revealed xanthogranulomatous endometritis. Since xanthogranulomatous endometritis may mimic endometrial malignancy clinically and pathologically as a result of the replacement of the endometrium and occasionally invasion of the myometrium by friable yellowish tissue composed of histiocytes, knowledge of this unusual inflammatory disease is needed for both clinicians and pathologists

Sample size, power and effect size revisited: simplified and practical approaches in pre-clinical, clinical and laboratory studies

Calculating the sample size in scientific studies is one of the critical issues as regards the scientific contribution of the study. The sample size critically affects the hypothesis and the study design, and there is no straightforward way of calculating the effective sample size for reaching an accurate conclusion. Use of a statistically incorrect sample size may lead to inadequate results in both clinical and laboratory studies as well as resulting in time loss, cost, and ethical problems. This review holds two main aims. The first aim is to explain the importance of sample size and its relationship to effect size (ES) and statistical significance. The second aim is to assist researchers planning to perform sample size estimations by suggesting and elucidating available alternative software, guidelines and references that will serve different scientific purposes

Association of serum ADMA, SDMA and L-NMMA concentrations with disease progression in COVID-19 patients

IntroductionThis study determines and compares the concentrations of arginine and methylated arginine products ((asymmetric dimethylarginine (ADMA), symmetric dimethylarginine (SDMA), n-monomethyl-1-arginine (L-NMMA) and homoarginine (HA)) for assessment of their association with disease severity in serum samples of COVID-19 patients. Materials and methodsSerum arginine and methylated arginine products of 57 mild-moderate and 29 severe (N = 86) COVID-19 patients and 21 controls were determined by tandem mass spectrometry. Moreover, the concentrations of some of the routine clinical laboratory parameters -neutrophil lymphocyte ratio (NLR), C-reactive protein, ferritin, D-dimer, and fibrinogen measured during COVID-19 follow-up were also taken into consideration and compared with the concentrations of arginine and methylated arginine products. ResultsSerum ADMA, SDMA and L-NMMA were found to be significantly higher in severe COVID-19 patients, than in both mild-moderate patients and the control group (P < 0.001 for each). In addition, multiple logistic regression analysis indicated L-NMMA (cut-off =120 nmol/L OR = 34, 95% confidence interval (CI) = 3.5-302.0, P= 0.002), CRP (cut-off = 32 mg/L, OR = 37, 95% CI = 4.8-287.0, P < 0.001), and NLR (cut-off = 7, OR = 22, 95% CI = 1.4-335.0, P = 0.020) as independent risk factors for identification of severe patients. ConclusionsThe concentration of methylated arginine metabolites are significantly altered in COVID-19 disease. The results of this study indicate a significant correlation between the severity of COVID-19 disease and concentrations of CRP, NLR and L-NMMA