Contrast Studies Research Articles

Comprehensive study of optical contrast, reflectance, and Raman spectroscopy of multilayer graphene

Graphene research has developed quite rapidly partially because even a monatomic layer can be visualized with a conventional optical microscope. Although optical properties of multilayer graphene such as optical contrast, reflectance (R), and Raman scattering have been well studied, they are studied independently and the thickness dependence is limited to a rather thin region. In this paper, the evolution of optical properties by thickness from monolayer to multilayer graphene up to 107 nm thick is studied comprehensively. The empirically known change of color of multilayer graphene is confirmed from the R, G and B intensities extracted from the optical images. It is also found that, as far as R for visible light is concerned, multilayer graphene is not necessarily considered as a layered material, and the refractive index for monolayer graphene is applicable even for the thickest multilayer graphene flake in this study. On the other hand, the layered structure and Raman scattering at each layer are essential to reproduce the G-band intensity of Raman scattering (I(G)). Not only the multiple reflection but also the interference of scattered Raman light should be considered for I(G) of multilayer graphene thicker than ∼30 nm.

The role of corneal epithelial thickness in ocular surface health

Abstract The corneal epithelium (CE), which is made up of five to seven layers, is crucial for maintaining the integrity of the cornea and the health of the ocular surface. The present review delves into the importance of corneal epithelial thickness (CET) in the identification and treatment of a range of ocular surface diseases (OSDs), such as keratoconus (KCN), dry eye disease (DED), and the aftermath of refractive procedures. Spectral-domain optical coherence tomography (SD-OCT) can be used to provide reliable and precise CET values, providing valuable insights into epithelial remodeling patterns and their correlation with disease severity. In DED, CE irregularities correlate with clinical symptoms, revealing a distinctive thinning pattern in the superior epithelium, especially in severe cases. This is attributed to mechanical friction from frequent blinking. Contrasting studies on overall CET in DED patients highlight the need for standardized assessment protocols. In KCN, epithelial thickness mapping (ETM) demonstrates specific thinning patterns, aiding in early detection and management. Postrefractive surgery, epithelial remodeling contributes to residual refractive errors, emphasizing the epithelium’s role in compensating for stromal irregularities. This review underscores the importance of CET analysis in clinical practice, advocating for the integration of advanced imaging technologies like SD-OCT. Understanding the dynamic changes in CET can enhance early diagnosis, guide surgical decisions, and improve treatment outcomes for various OSDs, ultimately contributing to better ocular health maintenance.

Grief in the face of terminal lucidity: an illustration with a contrastive case study

ABSTRACT ‘Pre-grief’ has been described as an adaptive process of preparation for the death of a loved one, through which the person gradually becomes accustomed to these prospects of separation and irremediable loss. However, this process can be disrupted, for example by an unexpected rebound, known as an episode of ‘terminal lucidity’, a sudden surge of cognitive functions previously altered (sometimes accompanied by physical changes), the hours or days immediately preceding death. Through the initial results of a study and two case studies of witnesses concerning the death of the same individual, we aim to illustrate various aftereffects of terminal lucidity episodes on relatives and the grieving process. The two cases used in this article demonstrate in fact contrasting ways of reacting to this phenomenon. We conclude that terminal lucidity episodes deserve more clinical attention, as they appear to have an impact on the grieving process, depending on contextual and personal variables.

Gastric Diverticulum: A Case Report with a Brief Literature Review

Gastric diverticula are the rarest type of diverticula detected in the gastrointestinal tract. With possible forms of congenital or acquired origin, it shows no gender predominance and is commonest in the ages of 50-70 years. Here, we report a case of gastric diverticulum detected in a 48-year-old female presenting with symptoms of dyspepsia and early satiety. The gastric diverticulum was detected during upper gastrointestinal endoscopy, which was further defined by an upper gastrointestinal contrast study. The patient recovered after two weeks of treatment with a proton pump inhibitor and a prokinetic, counselled regarding possible complications and advised to be reviewed if symptoms recur. Although gastric diverticula are rare, this can worsen with ulceration, bleeding, perforation, and malignant transformation. This emphasizes how crucial it is to identify and comprehend this condition in order to provide patients with the proper care and follow-up.

A Contrastive Analysis of the Connotations, Idiomaticity and Metaphoricity of Face in English and its Arabic Equivalent wədʒh

Objectives: This contrastive study aims to investigate the similarities and differences between the English term 'Face' and its Arabic equivalent, ‘‘wədʒh’, in terms of denotative meanings, connotative meanings, metaphorical meanings, and idiomatic uses. Methods: The data for this study were collected from a range of monolingual and bilingual dictionaries, as well as electronic databases. Results: The analysis has revealed that the term "wədʒh" encompasses a broader spectrum of meanings in Arabic compared to the word "face" in English. This divergence likely stems from the distinct cultures and historical backgrounds of the two languages. It is also found that both terms can carry connotations related to identity, expression, and communication. 'Face' and ‘‘wədʒh’ both imply the surface representation of an individual through metonymy and are frequently associated with emotions, reactions, and social interactions. Moreover, both terms can be used metaphorically to convey a wide array of concepts. Conversely, the two terms have their distinct set of idiomatic expressions, cultural nuances, and colloquial usages specific to their respective languages. Conclusions: Collectively, the current study is of significant value because it contributes to a more comprehensive understanding of how body parts function as sources of linguistic creativity and cultural symbolism in social communication.

Impact of Pre-Operative Ureteroscopy on Bladder Recurrence Following Nephroureterectomy for UTUC.

(1) Introduction: Diagnostic ureteroscopy (URS) is an important component in the workup of upper tract urothelial carcinoma (UTUC). Whether URS was associated with increased recurrence in the bladder was not fully concluded. The current study aimed to evaluate the implication of URS on the incidences of intravesical recurrence following radical nephroureterectomy (RNU) in non-metastatic UTUC patients without prior history of bladder cancer via multi-institutional data. (2) Patients and Methods: Data were obtained from the Clinical Research Office of the Endourology Society Urothelial Carcinomas of the Upper Tract (CROES-UTUC) registry, a prospective, multicentre database. Patients with non-metastatic UTUC treated with RNU were divided into two groups: those undergoing upfront RNU and those having diagnostic URS prior to RNU. Intravesical recurrence-free survival (IVRS) was the primary endpoint, evaluated through Kaplan-Meier analysis and multivariate Cox regression. Cases with adequate follow-up data were included. (3) Results: The analysis included 269 patients. Of these, 137 (50.9%) received upfront RNU and 132 (49.1%) received pre-RNU URS. The URS group exhibited an inferior 24-month IVRS compared to the upfront RNU group (HR = 1.705, 95% CI = 1.082-2.688; p = 0.020). Multivariate analysis confirmed URS as the only significant predictor of IVR (p = 0.019). Ureteric access sheath usage, flexible ureteroscopy, ureteric biopsy, retrograde contrast studies, and the duration of URS did not significantly affect IVRS. (4) Conclusions: Diagnostic URS prior to RNU was found to be associated with an increased risk of IVR in patients with UTUC. The risk was not significantly influenced by auxiliary procedures during URS. Physicians were advised to meticulously evaluate the necessity of diagnostic URS.

A Contrastive Study of Two News Reports on a Tea Picking Activity: in terms of Thematic Analysis

A Contrastive Study of Two News Reports on a Tea Picking Activity: in terms of Thematic Analysis

A Corpus-Based Contrastive Study of the Conceptual Metaphors of Warmth and Coolness in Chinese and English

A Corpus-Based Contrastive Study of the Conceptual Metaphors of Warmth and Coolness in Chinese and English

Left ventricular dysfunction in pulmonary arterial hypertension is attributed to underfilling rather than intrinsic myocardial disease: a CMR 2D phase contrast study

The pathophysiology underlying impaired LV function in PAH remains unclear, with some studies implicating intrinsic myocardial dysfunction and others pointing to LV underfilling. Evaluation of pulmonary vein area (PVA) and flow may offer novel, mechanistic insight by distinguishing elevated LV filling pressure common in myocardial dysfunction from LV underfilling. This study aimed to elucidate LV filling physiology in PAH by assessing PVA and flow using cardiac magnetic resonance (CMR) and compare pulmonary vein flow in PAH with HFrEF as a model representing elevated filling pressures, in addition to healthy controls. Patients with PAH or heart failure with reduced ejection fraction (HFrEF) referred for CMR were retrospectively reviewed, and healthy controls were included as reference. Pulmonary vein S, D and A-wave were compared between groups. Associations between pulmonary vein area (PVA) by CMR and echocardiographic indices of LV filling pressure were evaluated. Nineteen patients with PAH, 25 with HFrEF and 24 controls were included. Both PAH and HFrEF had lower ejection fraction and S-wave velocity than controls. PAH displayed smaller LV end-diastolic volumes than controls, while HFrEF demonstrated larger PVA and higher A-wave reversal. PVA was associated with mitral E/e′ ratio (r2 = 0.10; p = 0.03), e′ velocity (r2 = 0.23; p = 0.001) and left atrial volume (r2 = 0.07; p = 0.005). Among PAH, PVA was not associated with LV-GLS. A PVA cut-off of 2.3cm2 displayed 87% sensitivity and 72% specificity to differentiate HFrEF and PAH (AUC = 0.82). PAH displayed lower pulmonary vein S-wave velocity, smaller LV volume and reduced function compared with controls. Reduced LV function in PAH may be owing to underfilling rather than intrinsic myocardial disease. PVA demonstrates promise as a novel, non-invasive imaging marker to assess LV filling status.

A Contrastive Study of Persuasive Appeals in Online Advertising: Investigating Persuasive Appeals in Jordanian and Egyptian Telecommunication Advertisements During Ramadan

A Contrastive Study of Persuasive Appeals in Online Advertising: Investigating Persuasive Appeals in Jordanian and Egyptian Telecommunication Advertisements During Ramadan

Clinical management of intestinal malrotation in different age groups

PurposeIntestinal malrotation, characterized by abnormal intestinal positioning, can lead to severe complications like volvulus and internal hernias, especially in neonates and children. Our aim was to evaluate the diagnostic methods, treatment results and postoperative follow-up of pediatric patients treated for intestinal malrotation.MethodsThis retrospective study reviewed medical records of pediatric patients who underwent surgery for intestinal malrotation between January 2013 and January 2022. Data on demographics, symptoms, diagnostic approaches, surgical interventions, and postoperative outcomes were analyzed.ResultsThe study included 45 patients, with a male predominance (68.8%). Ages ranged from 1 day to 15 years, averaging 1.54 years. Presenting symptoms were acute abdomen (n = 21) and chronic abdominal pain with vomiting (n = 24). Diagnoses were established via physical exams and imaging, including upper gastrointestinal contrast studies and abdominal ultrasonography. All patients received the Ladd procedure, with some requiring necrotic bowel resection due to volvulus.ConclusionThe diagnosis and management of pediatric intestinal malrotation present significant challenges due to its variable symptoms and potential for life-threatening complications. Early and accurate diagnosis, followed by appropriate surgical management, is crucial. This study emphasizes the importance of diligent postoperative follow-up to identify and mitigate complications, particularly in younger and severely affected patients.

A Contrastive Study of the Deontic Modality in George Orwell’s Animal Farm

A Contrastive Study of the Deontic Modality in George Orwell’s Animal Farm

A Socio-Cognitive Linguistic Analysis of Male Dominance in Two Selected Memoirs: A Contrastive Study by: Dalia Kamal Abdel Hamied PhD Candidate- Suez University

A Socio-Cognitive Linguistic Analysis of Male Dominance in Two Selected Memoirs: A Contrastive Study by: Dalia Kamal Abdel Hamied PhD Candidate- Suez University

Optical contrast analysis of α-RuCl3 nanoflakes on oxidized silicon wafers

α-RuCl3, a narrow-band Mott insulator with a large work function, offers intriguing potential as a quantum material or as a charge acceptor for electrical contacts in van der Waals devices. In this work, we perform a systematic study of the optical reflection contrast of α-RuCl3 nanoflakes on oxidized silicon wafers and estimate the accuracy of this imaging technique to assess the crystal thickness. Via spectroscopic micro-ellipsometry measurements, we characterize the wavelength-dependent complex refractive index of α-RuCl3 nanoflakes of varying thickness in the visible and near-infrared. Building on these results, we simulate the optical contrast of α-RuCl3 nanoflakes with thicknesses below 100 nm on SiO2/Si substrates under different illumination conditions. We compare the simulated optical contrast with experimental values extracted from optical microscopy images and obtain good agreement. Finally, we show that optical contrast imaging allows us to retrieve the thickness of the RuCl3 nanoflakes exfoliated on an oxidized silicon substrate with a mean deviation of −0.2 nm for thicknesses below 100 nm with a standard deviation of only 1 nm. Our results demonstrate that optical contrast can be used as a non-invasive, fast, and reliable technique to estimate the α-RuCl3 thickness.

Euphemisms as Cultural and Social Phenomenon: Cross- Cultural Contrastive Study of English and Albanian Euphemistic Expressions

Euphemisms have been traditionally viewed as social taboos operative within the language-community and specifically as being “isolated” into their historical contexts and the established cultural conditions. Euphemisms help us to understand how taboo topics are conceived in cultural groups and what beliefs are accepted, rejected, or implicitly legitimated. Indeed, it is the social and cultural nature of euphemisms that make them so changing over time and across societies Different cultural backgrounds have reflected various views and attitudes towards delicate and touching issues such as taboos. In this context Albanian and English communities as distinguishable culturally identified societies have in an original and unrepetitive way designated the linguistic material in the process of euphemistic expressions generation and embedment. This contrastive analysis aims at investigating the way superstitious and social taboos have given rise to several types of euphemisms in both languages, linguistic materials which should be explained based on social cultural and mental grounds and peoples’ general belief that there is a somehow supernatural and instinctive hidden link between the linguistic sign and the referent it represents. At this point, it seems that Albanian and English communities have not “suffered” from similar unexplained fears, doubts, insecurities, and irrationalities. It is more than evident that while consulting the euphemistic corpus of Albanian and English euphemisms, distinguishable differences can be spotted.

Hirschsprung's disease. Management.

Hirschsprung's disease (HD) is a rare congenital disease that is characterised by the absence of ganglion cells in the myenteric plexus starting in the distal bowel. This results in distal functional obstruction and may lead to complications like enterocolitis. The treatment is surgical and requires the resection of the aganglionic segment, and the pull-through of normal intestine into the anal opening. However, even after successful surgery, patients may continue to have symptoms. Discuss current surgical techniques and management strategies for patients with postoperative symptoms after surgical correction of Hirschsprung's disease. A review of the literature was done through PubMed, with a focus on clinical management and approach. We describe the clinical problems that can occur after surgical correction. These include obstructive symptoms, enterocolitis, or faecal incontinence. A systematic approach for the evaluation of these patients includes the exclusion of anatomic, inflammatory, behavioural or motility related factors. Depending on the severity of the symptoms, the evaluation includes examination under anaesthesia, the performance of contrast studies, endoscopic studies, measurement of anal sphincter function and colonic motility studies. The treatment is focused towards addressing the different pathophysiological mechanisms, and may include medical management, botulinum toxin to the anal sphincter or rarely redo-operation. Patients with Hirschsprung's disease need to have surgical correction, and their postoperative long-term management is complex given a variety of associated problems that can occur after surgery. A systematic evaluation is necessary to provide appropriate therapy.

A Contrastive Study of Theme Types in Academic IELTS Essays Written by English-Majored Students and IELTS Candidates

The present study was conducted to investigate theme types in academic IELTS essays written by successful test-takers and English-majored students at Quang Nam university, applying Halliday (2014)’s functional model of Theme-Rheme in English, and then making a comparison between two different levels of performance: one with 7-7.5 band scores and the other written by English-majored students to identify similarities and differences between two essay groups. In this study, the data were 60 IELTS essays collected from two domains: 30 IELTS essays written by English majored students at Quang Nam university, and 30 sample essays scored from 7.0 to 7.5. The findings of this study are expected to enable IELTS test-takers in general and English-majored students at Quang Nam university in particular to take into account the prominent theme types of academic IELTS sample essays in order to make good use of thematic strategies to produce an effective and coherent piece of writing.

An improved double‐vector model predictive control strategy for four‐switch three‐phase inverter‐fed permanent magnet synchronous motor based on visualisation analysis considering DC voltage pulsation

AbstractTo address the problem of considerable current distortions in traditional single‐vector model predictive control (MPC) method for four‐switch three‐phase inverter (FSTPI)‐fed permanent magnet synchronous motor, a double‐vector MPC scheme has been studied. However, it still lacks a sufficient theoretical foundation, causing doubts about its effectiveness. To perfect this deficiency, a novel visualisation analysis scheme considering DC voltage pulsation is presented to demonstrate the validity of the traditional double‐vector MPC method for FSTPI. The analysis results reveal for the first time that the traditional double‐vector MPC method is not always superior to the single‐vector method as there is no zero voltage vector for FSTPI. So, a new virtual voltage vector is defined to compensate the deteriorated control performance caused by the absence of zero voltage vectors, based on which an improved double‐vector MPC method is further put forward to reduce the current ripples. Then, the presented visualisation analysis is adopted to demonstrate the validity of the improved MPC strategy under pulsating DC voltage conditions. Finally, a new voltage sector division technology is further put forward to simplify the implementation steps of the presented method. Contrastive experimental studies demonstrate the availability of the improved MPC strategy.

Comparative analysis of risk factors associated with degeneration of adjacent segments: zero-profile anchored spacer vs. anterior cervical plate and cage construct.

Anterior cervical discectomy and fusion (ACDF) is an established treatment for cervical degenerative disc disease, but cervical spine surgery may affect sagittal alignment parameters and induce adjacent segment degeneration (ASD). This study aimed to determine the risk factors for developing ASD following anterior cervical plate and cage (ACPC) compared with the use of zero-profile anchored spacer (ROI-C). A retrospective contrastive study included 105 patients who underwent ACPC or ROI-C between January 2014 and October 2019 at our treatment centre. There were 50 cases in the ROI-C group and 55 patients in the ACPC group. Clinical and radiological results and the incidence of ASD were assessed after surgery. All patients were further divided into the ASD and non-ASD groups for subgroup analysis. At each follow-up time, there was no statistically significant in radiographic parameters between the two groups. The overall ASD rate was higher in the ACPC group than in the ROI-C group (65.5% vs. 44.0%, p = 0.027). The low preoperative Cobb angle, low preoperative segment angle (SA), and loss of Cobb (ΔCobb) were significantly correlated with ASD. However, clinical outcomes were not associated with ASD at any postoperative follow-up visit. Equally good therapeutic effects were achieved with both the ROI-C and ACPC. The occurrence of ASD was considerably higher in the ACPC group than in the ROI-C group. The preoperative Cobb angle, preoperative SA, and ΔCobb were the most associated with an increase in the risk of ASD.

Speech Act of Request :A Contrastive Study Between EFL And ESL Undergraduate Students

This study explored the English request strategies and modifiers used by Malaysian and Saudi undergraduates. It also investigated the influence of social power and social distance on their choice of those strategies. Fifty Malaysian ESL and fifty Saudi EFL undergraduates participated in it. A discourse completion task was used to collect the data. Blum-Kulka et al.'s (1989) taxonomy was used to analyse request strategies and Martinez-Flor and Uso-Juan’s (2006) taxonomy was used to analyse request modifiers. Data was collected and analyzed quantitatively. The findings revealed that pragmatic competence varied according to context. Malaysian students in an English as a second language environment used more Conventionally Indirect request strategies than Saudi students did in an English as a foreign language environment. Non-Conventionally Indirect strategies were not used by Malaysians and were employed least often by Saudis. Social status and social distance had no significant influence on their use of request strategies. The study concluded by providing implications for English teachers to foster pragmatic competence among undergraduate students.