Physical and Optical Properties of Provisional Crown and Bridge Materials Fabricated Using CAD/CAM Milling or 3D Printing Technology

Objective: This study compared the physical and optical properties of provisional crown and bridge materials fabricated using CAD/CAM or 3D printing technology. Aim: To compare the biaxial flexural strength, microhardness, translucency parameter and gloss of provisional resin discs fabricated by milling PMMA blocks, versus two different resins printed using 3D printers. Hypothesis: There is no difference in the flexural strength, hardness, translucency and gloss of provisional resins fabricated by different digital technologies. Materials and methods: 90-disc shaped specimens for provisional resins were fabricated using a common digital file. These samples were equally distributed in three groups of 30 each. Group I samples were fabricated by milling specimens from a polymethyl methacrylate (PMMA). Group II samples were fabricated by printing urethane methacrylate resin using a 3D DLP printer. Group III samples were fabricated by printing acrylic ester resin using a 3D SLA printer. All samples were tested for biaxial flexural strength, translucency parameter, microhardness and gloss. Results A one-way ANOVA with Tukey HSD pair-wise comparisons was employed to analyze the data and answer the research questions. The mean values for biaxial flexural strength for milled polymethyl methacrylate (PMMA), urethane methacrylate resin and acrylic ester resin were 136.9 MPa, 101.6 MPa and 98.4 MPa respectively. The mean hardness values for the groups in the same order were 28.5, 9.7 and 14.8 respectively. The mean translucency parameter values for the groups in the same order were 3.8, 6.3 and 4.4 respectively. The mean gloss values for the groups in the same order were 3.9, 28.8 and 1.7 respectively. There was a statistically significant difference amongst the groups for all parameters tested. Conclusion The results of this study indicate that milled PMMA has superior flexural strength and hardness compared to 3D printed resins. Urethane methacrylate resin showed significantly better translucency and gloss when compared to milled PMMA or acrylic ester resin. Each approach to creating provisional restorations displayed advantages and disadvantages when comparing characteristics of clinical interest

A Polar Map Based Approach Using Retinal Fundus Images for Glaucoma Detection

Cup-to-disc ratio is commonly used as an important parameter for glaucoma screening, involving segmentation of the optic cup on fundus images. We propose a novel polar map representation of the optic disc, using a combination of supervised and unsupervised cup segmentation techniques, for detection of glaucoma. Instead of performing hard thresholding on the segmentation output to extract the cup, we consider the cup confidence scores inside the disc to construct a polar map, and extract sector-wise features for learning a glaucoma risk probability (GRP) for the image. We compare the performance of GRP vis-à-vis the cup-to-disc ratio (CDR). On an evaluation dataset of 100 images from the publicly available RIM-ONE database, our method achieves 82% sensitivity at 84% specificity, and 96% sensitivity at 60% specificity (AUC of 0.8964). Experiments indicate that the polar map based method can provide a more discriminatory glaucoma risk probability score compared to CDR

Adaptive Super-Candidate Based Approach for Detection and Classification of Drusen on Retinal Fundus Images

Identification and characterization of drusen is essential for the severity assessment of age-related macular degeneration (AMD). Presented here is a novel super-candidate based approach, combined with robust preprocessing and adaptive thresholding for detection of drusen, resulting in accurate segmentation with the mean lesion-level overlap of 0.75, even in cases with non-uniform illumination, poor contrast and con- founding anatomical structures. We also present a feature based lesion- level discrimination analysis between hard and soft drusen. Our method gives sensitivity of 80% for high specificity above 90% and high sensitivity of 95% for specificity of 70% on representative pathological databases (STARE and ARIA) for both detection and discrimination

Integrated approach for accurate localization of optic disc and macula

The location of three main anatomical structures in the retina namely the optic disc, the vascular arch, and the macula is significant for the analysis of retinal images. Presented here is a novel method that uses an integrated approach to automatically localize the optic disc and the macula with very high accuracy even in the presence of confounders such as lens artifacts, glare, bright pathologies and acquisition variations such as non-uniform illumination, blur and poor contrast. Evaluated on a collective set of 579 diverse pathological images from various publicly available datasets, our method achieves sensitivity > 99% and normalized localization error < 5% for optic disc and macula localization

Pembrolizumab-Associated Hypothyroidism: Case Report and Review of Literature

Pembrolizumab is a Programmed Death 1 (PD-1) inhibitor used to treat advanced malignant melanoma and metastatic non-small cell lung cancer. It causes various endocrinological side effects including immune mediated thyroiditis. Thyroiditis caused by Pembrolizumab can mimic other immune mediated thyroiditis like Hashimoto thyroiditis and Grave’s disease

Detection of retinal hemorrhages in the presence of blood vessels

Segmentation of hemorrhages helps in improving the efficiency of computer assisted image analysis of diseases like diabetic retinopathy and hypertensive retinopathy. Hemorrhages are blood leakages lying in close proximity to blood vessels, which makes their delineation from blood vessels challenging. We use multiresolution morphological processing with a view of achieving perceptual grouping of the hemorrhagic candidates occurring in variable shapes, sizes and textures. We propose a novel method of suppression of candidates lying on blood vessels while attaining a good segmentation of true hemorrhages including the ones attached to the vessels. Evaluated on 191 images having different degrees of pathological severity, our method achieved > 82% sensitivity at < 7 false positives per image (FPPI). We further observe that the sensitivity is higher for candidates with bigger sizes

Paediatric Restrictive Cardiomyopathy - Diagnosis and Challenges: A report of two cases

Restrictive cardiomyopathy is one of the rarest forms of cardiomyopathies in pediatric patients characterized by impaired myocardial relaxation or compliance with restricted ventricular filling, leading to a reduced diastolic volume with a preserved systolic function. We report two cases – a 5-year-old boy who presented with abdominal distension and palpitation with family history of similar complaints but no definite genetic diagnosis as yet, and a 5-year-old girl who presented with chronic cough and shortness of breath. Both cases were diagnosed in Sultan Qaboos University Hospital in 2019 and are managed supportively with regular outpatient follow-up. This is the first series of reported cases of pediatric restrictive cardiomyopathy from Oman. Keywords: restrictive cardiomyopathy, cardiomyopathy in children, heart failure in children

LC-MS based metabolite profiling, in-vitro antioxidant and in-vivo antihyperlipidemic activity of Nigella sativa extract

The aim of this study was to identify the bioactive phytoconstituents present in the aqueous extract of Nigella sativa and also, to evaluate the antioxidant and antihyperlipidemic activity in Wistar rats. The LC-MS/MS analysis was assessed for the determination of different bioactive compounds present in N. sativa extract. Total phenolic and flavonoid content were determined by using validated Folin-Ciocalteu and Aluminum chloride colorimetric methods, respectively. The in-vitro antioxidant and in-vivo antihyperlipidemic activity in Wistar rats were also evaluated. Preliminary phytochemical screening of the extract showed the presence of alkaloids, flavonoids, phenols, glycosides, and amino acids in the aqueous extract. The bioactive compounds of the aqueous extract were identified through LC-MS/MS analysis. The in-vitro antioxidant activity of N. sativa showed the highest free radical scavenging capacity in DPPH, H2O2, and OH radical scavenging assays with IC50 values 11.916 ± 2.828, 30.294 ± 13.790, and 12.048 ± 2.828 µg/mL, respectively. Evaluation of antihyperlipidemic activity of extract in Wistar rats showed that a high dose (800 mg/kg) of extract significantly decreased total cholesterol (TC) 71.76 ± 6.91 mg/dL, TG 83.6 ± 8.09 mg/dL, low-density lipoproteins (LDL-c) 33.86 ± 6.05 mg/dL, very low-density lipoproteins (VLDL-c) 16.72 ± 1.61 mg/dL level in blood. However, the HDL-C level was significantly improved (21.18 ± 1.80 mg/dL) as compared to HFD-induced control rats (11.76 ± 1.14 mg/dL) after 28 days of treatment. Also, at the same dose, animal body weight was also decreased to 162.6 ± 16.40 g compared with control 184.4 ± 10.24 g. The aqueous extract of N. sativa was found to be an effective natural source of antioxidant and hypolipidemic agents. This activity was attributed to the presence of diverse bioactive compounds in it