Promising Nitrogen-Doped Graphene Derivatives; A Case Study for Preparations, Fabrication Mechanisms, and Applications in Perovskite Solar Cells

Graphene (G) has been a game-changer for conductive optical devices and has shown promising aspects for its implementation in the power industry due to its diverse structures. Graphene has played an essential role as electrodes, hole transport layers (HTLs), electron transport layers (ETLs), and a chemical modulator for perovskite layers in perovskite solar cells (PSCs) over the past decade. Nitrogen-doped graphene (N-DG) derivatives are frequently evaluated among the existing derivatives of graphene because of their versatility of design, easy synthesis process, and high throughput. This review presents a state-of-the-art overview of N-DG preparation methods, including wet chemical process, bombardment, and high thermal treatment methods. Furthermore, it focuses on different structures of N-DG derivatives and their various applications in PSC applications. Finally, the challenges and opportunities for N-DG derivatives for the continuous performance improvement of PSCs have been highlighted.

Prediction of high-risk esophageal varices in patients with compensated cirrhosis using albumin-bilirubin-platelet score

BACKGROUND

Despite the fact that endoscopy is the gold standard for screening of high-risk varices (HRVs) in patients with compensated cirrhosis, it is invasive, costly and not necessary for all patients. So, noninvasive tests can replace endoscopy. We aimed at evaluating the albumin-bilirubin-platelet (ALBL-PLT) score as a noninvasive test in predicting HRVs in compensated cirrhotic patients versus Baveno VI and extended Baveno VI criteria.

METHODS

patients with compensated cirrhosis (n = 204) were included. Laboratory parameters, esophagogastroduodenoscopy (EGD) and liver stiffness measurement by transient elastography were done. Classification of patients according to the status of HRVs was done. We compared both groups on the basis of ALBL-PLT score, Baveno VI and extended Baveno VI criteria.

RESULTS

Among the total patients, 96/204 (47%) patients had HRVs. They have higher liver stiffness measurement than those without HRVs (33 ± 13.1 versus 19.3 ± 8.25, CI, -19.94, -7.31, P value <0.001). Also, all HRVs patients have an ALBL-PLT score of more than 3. The area under the receiver operating characteristic curve for the ALBL-PLT score is higher than that for Baveno VI and extended Baveno VI criteria (0.894 versus 0.722 and 0.792, respectively).

CONCLUSION

ALBL-PLT score of more than three has a good predictive value in predicting HRVs among compensated cirrhotic patients.

Newly Diagnosed Diabetes in Patients with COVID-19: Different Types and Short-Term Outcomes

A great global concern is currently focused on the coronavirus disease 2019 (COVID-19) pandemic and its associated morbidities. The goal of this study was to determine the frequency of newly diagnosed diabetes mellitus (DM) and its different types among COVID-19 patients, and to check the glycemic control in diabetic cases for three months. After excluding known cases of DM, 570 patients with confirmed COVID-19 were studied. All participants were classified as non-diabetic or newly discovered diabetic. According to hemoglobin A1c (HbA1c) and fasting insulin, newly discovered diabetic patients were further classified into pre-existing DM, new-onset type 1 DM, and new-onset type 2 DM. Glycemic control was monitored for three months in newly diagnosed diabetic patients. DM was diagnosed in 77 patients (13.5%); 12 (2.1%) with pre-existing DM, 7 (1.2%) with new-onset type 1 DM, and 58 (10.2%) with new-onset type 2 DM. Significantly higher rates of severe infection and mortality (p < 0.001 and p = 0.046) were evident among diabetic patients. Among survived diabetic patients (n = 63), hyperglycemia and the need for anti-diabetic treatment persisted in 73% of them for three months. COVID-19 was associated with a new-onset of DM in 11.4% of all participants and expression of pre-existing DM in 2.1% of all participants, both being associated with severe infection. COVID-19 patients with newly diagnosed diabetes had high risk of mortality. New-onset DM persisted for at least three months in more than two-thirds of cases.

Combined therapy with conventional trans-arterial chemoembolization (cTACE) and microwave ablation (MWA) for hepatocellular carcinoma >3-<5 cm

PURPOSE

To compare safety and efficacy of combined therapy with conventional transarterial chemoembolization (cTACE)+microwave ablation (MWA) versus only TACE or MWA for treatment of hepatocellular carcinoma (HCC) >3-<5 cm.

METHODS

This randomized controlled trial (NCT04721470) screened 278 patients with HCC >3-<5 cm. Patients were randomized into three groups: 90 underwent TACE (Group 1); 95 underwent MWA (Group 2); and 93 underwent combined therapy (Group 3). Patients were followed-up with contrast-enhanced CT or MRI. Images were evaluated and compared for treatment response and adverse events based on modified response evaluation criteria in solid tumor. Serum alpha-fetoprotein (AFP) concentration was measured at baseline and during every follow-up visit.

RESULTS

Final analysis included 265 patients (154 men, 111 women; mean age = 54.5 ± 11.8 years; range = 38-76 years). Complete response was achieved by 86.5% of patients who received combined therapy compared with 54.8% with only TACE and 56.5% with only MWA (p = 0.0002). The recurrence rate after 12 months was significantly lower in Group 3 (22.47%) than Groups 1 (60.7%) and 2 (51.1%) (p = 0.0001). The overall survival rate (three years after therapy) was significantly higher in Group 3 (69.6%) than Groups 1 (54.7%) and 2 (54.3%) (p = 0.02). The mean progression-free survival was significantly higher in Group 3 than groups 1 and 2 (p < 0.001). A decrease in AFP concentration was seen in 75%, 63%, and 48% patients of Group 3, 2, and 1, respectively.

CONCLUSIONS

Combined therapy with cTACE + MWA is safe, well-tolerated, and more effective than TACE or MWA alone for treatment of HCC >3-<5 cm.

Morbidity and mortality during hepatitis C treatment using sofosbuvir and daclatasvir with or without ribavirin, in a cohort of Egyptian patients

BACKGROUND

Though direct-acting antiviral agents (DAAs) therapy is associated with a high cure rate of hepatitis C virus infection, a potential risk of serious adverse events (SAEs) exists. The aim of this study was to determine the incidence and predictors of morbidity and mortality related to DAAs therapy.

METHODS

This prospective study was conducted on a real word cohort of 1562 treatment naïve chronic hepatitis C (CHC) Egyptian patients, who received 12-weeks therapy with sofosbuvir (SOF) plus daclatasvir (DCV) ± ribavirin (RBV). The incidence and predictors of SAEs and mortality during treatment course and over the following 12 weeks were recorded.

RESULTS

The mean age of study participants was 51.38 ± 9.70 years (55.22%, males). Liver cirrhosis was defined in 72.4% of participants. SAEs were recorded in 120 participants (7.68%), including hepatic decompensation, gastrointestinal bleeding, anemia and hepatocellular carcinoma. Nine patients (0.58%) died and 69 patients (4.42%) discontinued therapy due to SAEs. Severity of cirrhosis was the significant predictor of morbidities and mortality. Hepatic decompensation was predicted by baseline serum albumin [cutoff value: 3.00 g/dL, area under the receiver operating characteristic curve (AUROC): 0.953] and serum bilirubin (cutoff value: 1.75 mg/dL, AUROC: 0.940).

CONCLUSION

The risk of morbidity and mortality related to SOF/DCV ± RBV therapy in CHC patients is small and is significantly linked to advanced cirrhosis.

Synthesis and Antimicrobial Activity of 5-(morpholinosulfonyl)isatin Derivatives Incorporating a Thiazole Moiety

This article describes the synthesis of novel 5-(morpholinosulfonyl)isatin derivatives having biologically active thiazole moiety were synthesized via 2 synthetic routes. The first route involved interaction of 5-(morpholino-sulfonyl) isatin with aminothiazole derivatives to give the Schiff's base derivatives (2, 3). The second route involved preparation of thiosemicarbazones (4-7) by treatment of 5-(morpholino- sulfonyl) isatin with thiosemicarbazides followed by cycloalkylation of the products with halogenated compounds to give the thiazole derivatives (8-19). Most of the synthesized compounds were screened against Gram (+), Gram (-) bacterial and fungi. The best gram positive activity was displayed by compounds 1, 13, 14, 15, 16 and 18 and the best gram negative bacteria was showed by compounds 1, 12, 13, 15, and 19, whereas compounds 1, 12, 13, 15, and 19 exhibited the best antifungal activity.

Multi-stencils fast marching methods: a highly accurate solution to the eikonal equation on cartesian domains

A wide range of computer vision applications require an accurate solution of a particular Hamilton- Jacobi (HJ) equation, known as the Eikonal equation. In this paper, we propose an improved version of the fast marching method (FMM) that is highly accurate for both 2D and 3D Cartesian domains. The new method is called multi-stencils fast marching (MSFM), which computes the solution at each grid point by solving the Eikonal equation along several stencils and then picks the solution that satisfies the upwind condition. The stencils are centered at each grid point and cover its entire nearest neighbors. In 2D space, 2 stencils cover the 8-neighbors of the point, while in 3D space, 6 stencils cover its 26-neighbors. For those stencils that are not aligned with the natural coordinate system, the Eikonal equation is derived using directional derivatives and then solved using higher order finite difference schemes. The accuracy of the proposed method over the state-of-the-art FMM-based techniques has been demonstrated through comprehensive numerical experiments.

Virtual fly-over: a new visualization technique for virtual colonoscopy

In this paper, we propose a new visualization technique for virtual colonoscopy (VC). The proposed method is called Virtual Fly-Over, which splits the entire colon anatomy into exactly two halves. Then, it assigns a virtual camera to each half to perform fly-over navigation, which has several advantages over both traditional fly-through and related methods. First, by controlling the elevation of the camera, there is no restriction on its field of view (FOV) angle (e.g., >90 degrees) to maximize visualized surface areas, and hence no perspective distortion. Second, the camera viewing volume is perpendicular to each colon half, so potential polyps that are hidden behind haustral folds are easily found. Finally, because the orientation of the splitting surface is controllable, the navigation can be repeated at a different split orientation to overcome the problem of having a polyp that is divided between the two halves of the colon. Quantitative experimental results on 15 clinical datasets have shown that the average surface visibility coverage is 99.59 +/- 0.2%.

Cerebrovascular segmentation from TOF using stochastic models

In this paper, we present an automatic statistical approach for extracting 3D blood vessels from time-of-flight (TOF) magnetic resonance angiography (MRA) data. The voxels of the dataset are classified as either blood vessels or background noise. The observed volume data is modeled by two stochastic processes. The low level process characterizes the intensity distribution of the data, while the high level process characterizes their statistical dependence among neighboring voxels. The low level process of the background signal is modeled by a finite mixture of one Rayleigh and two normal distributions, while the blood vessels are modeled by one normal distribution. The parameters of the low level process are estimated using the expectation maximization (EM) algorithm. Since the convergence of the EM is sensitive to the initial estimate of the model parameters, an automatic method for parameter initialization, based on histogram analysis, is provided. To improve the quality of segmentation achieved by the proposed low level model especially in the regions of significantly vascular signal loss, the high level process is modeled as a Markov random field (MRF). Since MRF is sensitive to edges and the intracranial vessels represent roughly 5% of the intracranial volume, 2D MRF will destroy most of the small and medium sized vessels. Therefore, to reduce this limitation, we employed 3D MRF, whose parameters are estimated using the maximum pseudo likelihood estimator (MPLE), which converges to the true likelihood under large lattice. Our proposed model exhibits a good fit to the clinical data and is extensively tested on different synthetic vessel phantoms and several 2D/3D TOF datasets acquired from two different MRI scanners. Experimental results showed that the proposed model provides good quality of segmentation and is capable of delineating vessels down to 3 voxel diameters.

PDE-Based Three Dimensional Path Planning for Virtual Endoscopy

Three dimensional medial paths or curve skeletons (CS) are an essential component of any virtual endoscopy (VE) system, because they serve as flight paths for a virtual camera to navigate the human organ and to examine its internal structures. In this paper, we propose a novel framework for computing flight paths of tubular structures for VE using partial differential equation (PDE). The method works in two passes. In the first pass, the overall topology of the organ is analyzed and its important topological nodes are identified, while in the second pass, the actual flight paths are computed by tracking them starting from each identified node. The proposed framework is robust, fully automatic, computationally efficient, and computes CS that are centered, connected, thin, and less sensitive to boundary noise. We have extensively validated the robustness of the proposed method both quantitatively and qualitatively against several synthetic phantoms and clinical datasets.

Video reconstructions in dentistry

OBJECTIVES

To present two practical techniques for three-dimensional (3D) modeling of the human jaw from a sequence of intra-oral images.

DESIGN

A data acquisition system consists of: 3D digitizing arm, CCD camera and a laser projector in addition to a software module of two 3D modeling techniques; shape from shading (SFS) and space carving (SC).

SETTING AND SAMPLE POPULATION

Several experiments have been conducted on a sample of students at the Computer Vision and Image Processing (CVIP) Laboratory at the University of Louisville, Louisville, KY. Other experiments were performed on solid models of human jaw.

EXPERIMENTAL VARIABLE

The SFS technique, using perspective projection and camera calibration, extracts the 3D information from a sequence of two-dimensional images of the jaw. Data fusion of range data and 3D registration techniques develop the complete jaw model. The SC approach is implemented on a sequence of calibrated images. On the two reconstructions, we fit a mesh model to the data, in order to create a solid 3D model.

OUTCOME MEASURE

The accuracy of the reconstructed 3D model of human jaw is calculated based on the measurements on real jaws.

RESULTS

The SFS-based technique seems to provide more faithful information about the shape of the tooth tops. However, the SC algorithm successfully reconstructed 3D models of the human jaw with sub-millimeter accuracy, which is as accurate as (or even better than) the first technique without using any range measurements or laser projectors. The average error in distance calculation was found to be 0.74 mm, which is an acceptable resolution for many orthodontics and maxillofacial applications.

CONCLUSION

Accurate 3D reconstruction of the human jaw enables many orthodontics and dental imaging research findings to be applied directly to a digital jaw model--not to a cast--using computer vision and medical imaging tools.

A 3-D reconstruction system for the human jaw using a sequence of optical images

This paper presents a model-based vision system for dentistry that will assist in diagnosis, treatment planning, and surgical simulation. Dentistry requires an accurate three-dimensional (3-D) representation of the teeth and jaws for diagnostic and treatment purposes. The proposed integrated computer vision system constructs a 3-D model of the patient's dental occlusion using an intraoral video camera. A modified shape from shading (SFS) technique, using perspective projection and camera calibration, extracts the 3-D information from a sequence of two-dimensional (2-D) images of the jaw. Data fusion of range data and 3-D registration techniques develop the complete jaw model. Triangulation is then performed, and a solid 3-D model is reconstructed. The system performance is investigated using ground truth data, and the results show acceptable reconstruction accuracy.

Classification algorithms for quantitative tissue characterization of diffuse liver disease from ultrasound images

Visual criteria for diagnosing diffused liver diseases from ultrasound images can be assisted by computerized tissue classification. Feature extraction algorithms are proposed in this paper to extract the tissue characterization parameters from liver images. The resulting parameter set is further processed to obtain the minimum number of parameters which represent the most discriminating pattern space for classification. This preprocessing step has been applied to over 120 distinct pathology-investigated cases to obtain the learning data for classification. The extracted features are divided into independent training and test sets, and are used to develop and compare both statistical and neural classifiers. The optimal criteria for these classifiers are set to have minimum classification error, ease of implementation and learning, and the flexibility for future modifications. Various algorithms of classification based on statistical and neural network methods are presented and tested. The authors show that very good diagnostic rates can be obtained using unconventional classifiers trained on actual patient data.

Detection of pulse and respiratory signals from the wrist using dry electrodes

A dry, tetrapolar electrode array was used to detect the differential impedance signal at the wrists of 11 adult human subjects. Experiments were conducted to determine the importance of potential-sensing electrode spacing to detect each wearer's pulse rate and respiratory rate. The current-injecting electrodes were at the sides of the wrist; the potential-sensing electrodes were on the volar wrist surface. The bandwidth-filtered root-mean-square amplitudes of the pulse and respiratory components were computed and found to increase with increasing electrode spacing. Optimum spacings were slightly different for the pulse and respiration and were slightly different in the male and female subjects. A spacing for the potential electrodes of about 60% of the wrist hemicircumference is a good compromise for detecting respiration and pulse.

Teleradiology for dentistry

As the world enters the "telecosm," the importance of rapid information transfer will grow. It is not unusual for the average American to have a beeper on his or her belt, a cellular telephone in the car, a telephone with remote access answering machine, voice mail, call forwarding, a home fax, and a personal computer networked with a commercial purchasing and information retrieval service such as CompuServe or Prodigy. Conventional cellular telephones, introduced in 1983, numbered approximately 6.4 million in the United States by January, 1992. This is a measure of the importance placed on rapid interpersonal communication. Undoubtedly, patients will begin to expect at least the same degree of efficiency in communications on the part of health care providers, including dentists. There are great potentials for expediting prior approval and reducing costs for dental care as dentists obtain new, lower-priced, direct digital imaging systems, especially as ISDN and electronic mail systems become more available and less costly. It should be possible to reduce insurance costs by minimizing the numbers of clerical staff needed to open, check, and return submitted radiographs. Centralized diagnostic centers for second or expert opinions both for the dental profession and for the insurance carriers are additional pluses. There are potential savings in mailing costs and in reducing travel required of the patient living in a remote region to obtain a second opinion. Transmission using commercially available access to Internet/NSFNET is already possible for a small monthly fee. Nothing, other than a basic personal computer with graphics capabilities, is needed to transmit and receive files once the image is in a digital form. Electronic imaging and image transmission are here.

Expediting prior approval and containing third-party costs for dental care

Dental insurance carriers frequently require referral of radiographs for determination of prior approval. Radiographs are also often used for obtaining expert opinions before finalizing diagnoses and establishing treatment plans. Traditionally, such referrals have been carried out using the original or duplicate films transmitted through the postal system. Studies concerning alternative communication media for data transmission are presented, namely, the use of switched-digital telephone lines and of electronic mail networks.

Communication in digital radiology

The long-distance transfer of dental radiographs was explored as early as the 1920s. The practicality of such image transfer has improved through advances in telecommunications and computer networks (both hardware and software) and the emerging trends towards direct and indirect digital imaging techniques for recording oral and maxillofacial radiographs. This paper reviews the current status of communication in digital dental radiology. It is illustrated by personal observations from a variety of demonstration projects.