Evolution of Glassy Carbon Derived from Pyrolysis of Furan Resin.

Glassy carbon (GC) material derived from pyrolyzed furan resin was modeled by using reactive molecular dynamics (MD) simulations. The MD polymerization simulation protocols to cure the furan resin precursor material are validated via comparison of the predicted density and Young's modulus with experimental values. The MD pyrolysis simulations protocols to pyrolyze the furan resin precursor is validated by comparison of calculated density, Young's modulus, carbon content, sp2 carbon content, the in-plane crystallite size, out-of-plane crystallite stacking height, and interplanar crystallite spacing with experimental results from the literature for furan resin derived GC. The modeling methodology established in this work can provide a powerful tool for the modeling-driven design of next-generation carbon-carbon composite precursor chemistries for thermal protection systems and other high-temperature applications.

Evolution of TNM Classification for Clinical Staging of Oral Cancer: The Past, Present and the Future.

Purpose: The AJCC (American Joint Committee on Cancer) Cancer Staging Manual, 1st Edition, was published in 1977 which focused on the TNM classification and staging of cancer to allow easy communication, formulation of a treatment plan and predict the prognosis, among the medical fraternity. Methods: Ever since the beginning, various modifications of the classification were introduced and released by the joint collaboration of AJCC and UICC (International Union Against Cancer) in various editions of cancer staging manuals. Results: The present review article was kept focused onto the changes introduced in the clinical staging of cancers of oral cavity. These changes came a long way since 1st edition 1944, to the eighth edition which was published in 2017. Conclusions: This article is a critical review on the past and present perspectives of the TNM classification of the oral cavity that were addressed and changed, adding a light on the future trends or necessary inclusions that would formulate a much easily acceptable and useful classification system.

Surgeons Approach to Glandular Odontogenic Cyst of Mandible Mimicking Mucoepidermoid Carcinoma.

This article reports a case of glandular odontogenic cyst in a 70-year-old male and discusses the clinical, radiological and histopathological features. The present case shows treatment of GOC which effected the body of mandible with infiltration into submandibular gland.

Wetting Simulations of High-Performance Polymer Resins on Carbon Surfaces as a Function of Temperature Using Molecular Dynamics.

Resin/reinforcement wetting is a key parameter in the manufacturing of carbon nanotube (CNT)-based composite materials. Determining the contact angle between combinations of liquid resin and reinforcement surfaces is a common method for quantifying wettability. As experimental measurement of contact angle can be difficult when screening multiple high-performance resins with CNT materials such as CNT bundles or yarns, computational approaches are necessary to facilitate CNT composite material design. A molecular dynamics simulation method is developed to predict the contact angle of high-performance polymer resins on CNT surfaces dominated by aromatic carbon, aliphatic carbon, or a mixture thereof (amorphous carbon). Several resin systems are simulated and compared. The results indicate that the monomer chain length, chemical groups on the monomer, and simulation temperature have a significant impact on the predicted contact angle values on the CNT surface. Difunctional epoxy and cyanate ester resins show the overall highest levels of wettability, regardless of the aromatic/aliphatic nature of the CNT material surface. Tetrafunctional epoxy demonstrates excellent wettability on aliphatic-dominated surfaces at elevated temperatures. Bismaleimide and benzoxazine resins show intermediate levels of wetting, while typical molecular weights of polyether ether ketone demonstrate poor wetting on the CNT surfaces.

In Situ Transmission Electron Microscopy for Ultrahigh Temperature Mechanical Testing of ZrO2.

This work demonstrates a novel approach to ultrahigh-temperature mechanical testing using a combination of in situ nanomechanical testing and localized laser heating. The methodology is applied to characterizing and testing initially nanograined 10 mol % Sc2O3-stabilized ZrO2 up to its melting temperature. The results suggest that the low-temperature strength of nanograined, d < 50 nm, oxides is not influenced by creep. Tensile fracture of ZrO2 bicrystals produce a weak-temperature dependence suggesting that grain boundary energy dominates brittle fracture of grain boundaries even at high homologous temperatures; for example, T = 2050 °C or T ≈ 77% Tmelt. The maximum temperature for mechanical testing in this work is primarily limited by the instability of the sample, due to evaporation or melting, enabling a host of new opportunities for testing materials in the ultrahigh-temperature regime.

Clonidine: An Adjuvant to Adrenaline in Local Anesthesia for Third Molar Surgery.

PURPOSE: The aim of the study is to compare the efficacy of anesthesia and hemodynamic parameters of clonidine and epinephrine in lignocaine for lower third molar surgery. MATERIALS AND METHODS: Thirty healthy controls with impacted mandibular third molar were randomly selected from both sexes between the age group of 20-47 years. Patients were divided equally into two groups: Group I (Adrenaline group) and Group II (Clonidine group). Patients received 2.5 ml of 2% lignocaine with adrenaline (12.5 µg/ml) in Adrenaline group and 2.5 ml of 2% lignocaine with clonidine (15 µg/ml) in Clonidine group. Hemodynamic parameters (heart rate, systolic blood pressure [SBP], diastolic blood pressure [DBP], and mean arterial pressure [MAP]) were recorded preoperatively, intraoperatively, and postoperatively. The onset of anesthesia and duration of anesthesia were recorded using pinprick test for both groups. Postoperatively, patients were evaluated for pain experience by the visual analog scale and verbal rating scale. RESULTS: Lignocaine with clonidine intraoperatively and postoperatively decreases SBP and DBP and MAP compared to lignocaine with adrenaline. There was no significant difference in the onset and duration of anesthesia in both the groups. There was a statistically significant difference seen in the visual analog scale, but no statistically significant difference was seen in the verbal rating scale. CONCLUSION: Clonidine has similar efficacy as that of adrenaline with better hemodynamic parameters and can be used as an alternative to adrenaline for third molar surgeries.

Comparing the Mechanical Response of Di-, Tri-, and Tetra-functional Resin Epoxies with Reactive Molecular Dynamics.

The influence of monomer functionality on the mechanical properties of epoxies is studied using Molecular Dynamics (MD) with the Reax Force Field (ReaxFF). From deformation simulations, the Young's modulus, yield point, and Poisson's ratio are calculated and analyzed. The results demonstrate an increase in stiffness and yield strength with increasing resin functionality. Comparison between the network structures of distinct epoxies is further advanced by the Monomeric Degree Index (MDI). Experimental validation demonstrates the MD results correctly predict the relationship in Young's moduli. Therefore, ReaxFF is confirmed to be a useful tool for studying the mechanical behavior of epoxies.

Case report: congenital rubella syndrome: a rare but persistent concern in the United States.

In countries such as the United States where rubella virus infections are rare, congenital rubella syndrome (CRS) may not be recognized in a timely manner. However, the syndrome still appears in this country, often in infants of mothers emigrating from countries with absent or suboptimal national vaccination programs. We describe a case of CRS in a term baby born to a recent US immigrant who developed a primary varicella infection in late pregnancy and demonstrated IgG titers to rubella at delivery. At presentation, the neonate had both classical findings as well as less reported vascular and neurological abnormalities seen in infants with CRS.

First-principles computation of structural, elastic and magnetic properties of Ni2FeGa across the martensitic transformation.

The structural stabilities, elastic, electronic and magnetic properties of the Heusler-type shape memory alloy Ni(2)FeGa are calculated using density functional theory. The volume conserving tetragonal distortion of the austenite Ni(2)FeGa find an energy minimum at c/a = 1.33. Metastable behaviour of the high temperature cubic austenite phase is predicted due to elastic softening in the [110] direction. Calculations of the total and partial magnetic moments show a dominant contribution from Fe atoms of the alloy. The calculated density of states shows a depression in the minority spin channel of the cubic Ni(2)FeGa just above the Fermi level which gets partially filled up in the tetragonal phase. In contrast to Ni(2)MnGa, the transition metal spin-down states show partial hybridization in Ni(2)FeGa and there is a relatively high electron density of states near the Fermi level in both phases.

A numerical investigation into possible mechanisms by that the A629P mutant of ATP7A causes Menkes Disease.

We study in silico possible mechanisms by that the A629P mutant of ATP7A causes Menkes Disease. Our results indicate that the mutation does not have appreciable affects on the stability of copper-bound states but rather destabilizes the characteristic end-to-end ß-sheet. In this way, the mutation presumably increases the probability for aggregation and/or degradation leading to decreased concentration of the monomer.

ANCA negative pauci-immune glomerulonephritis with systemic involvement.

Systemic vasculitides (SV) are a group of diseases with multi system involvement and varied clinical presentation. Anti-neutrophil cytoplasmic antibody (ANCA) testing has high sensitivity and specificity for SV. We describe the clinical course of four patients who had pauci-immune glomerulonephritis with systemic involvement without serological ANCA positivity; they were followed up for a cumulative 55 patient months. The mean Birmingham vasculitis score score was 23. All four had systemic symptoms with arthralgias and fever (100%). Neurological manifestations were seen in two patients (66%). Accelerated hypertension was seen in one. One patient had pulmonary renal syndrome. Renal manifestation was characterized by nephrotic range of proteinuria with glomerular hematuria in all (100%) and severe renal failure requiring dialysis in three (66%). At admission the mean blood urea was 146 +/- 19 mg% and mean serum creatinine was 5.6 +/- 1.9 mg%. Renal biopsy revealed focal proliferative glomerulonephritis with crescents only in 20-30% of glomeruli. There was significant chronic interstitial involvement in two patients (66%). Therapy with pulse steroids, cyclophosphamide, and mycophenolate mofetil (MMF) was effective in three patients while one died with lung hemorrhage. In conclusion, majority of patients with ANCA negative pauci-immune glomerulonephritis have multi-system involvement at admission. Renal biopsy is characterized by focal proliferative lesions with crescents and significant chronic interstitial fibrosis. Immunosuppressive drugs in the form of corticosteroids, MMF and cyclophosphamide bring about marked renal recovery in most patients.

Theoretical study of physisorption of nucleobases on boron nitride nanotubes: a new class of hybrid nano-biomaterials.

We investigate the adsorption of the nucleic acid bases-adenine (A), guanine (G), cytosine (C), thymine (T) and uracil (U)-on the outer wall of a high curvature semiconducting single-walled boron nitride nanotube (BNNT) by first-principles density functional theory calculations. The calculated binding energy shows the order: G > A approximately C approximately T approximately U, implying that the interaction strength of the high curvature BNNT with the nucleobases, G being an exception, is nearly the same. A higher binding energy for the G-BNNT conjugate appears to result from hybridization of the molecular orbitals of G and the BNNT. A smaller energy gap predicted for the G-BNNT conjugate relative to that of the pristine BNNT may be useful in the application of this class of biofunctional materials to the design of next-generation sensing devices.

First-principles study of physisorption of nucleic acid bases on small-diameter carbon nanotubes.

We report the results of our first-principles study based on density functional theory on the interaction of the nucleic acid base molecules adenine (A), cytosine (C), guanine (G), thymine (T), and uracil (U), with a single-walled carbon nanotube (CNT). Specifically, the focus is on the physisorption of base molecules on the outer wall of a (5, 0) metallic CNT possessing one of the smallest diameters possible. Compared to the case for CNTs with large diameters, the physisorption energy is found to be reduced in the high-curvature case. The base molecules exhibit significantly different interaction strengths and the calculated binding energies follow the hierarchy G>A>T>C>U, which appears to be independent of the tube curvature. The stabilizing factor in the interaction between the base molecule and CNT is dominated by the molecular polarizability that allows a weakly attractive dispersion force to be induced between them. The present study provides an improved understanding of the role of the base sequence in deoxyribonucleic acid (DNA) or ribonucleic acid (RNA) in their interactions with carbon nanotubes of varying diameters.

Structural, energetic, electronic, bonding, and vibrational properties of Ga3O, Ga3O2, Ga3O3, Ga2O3, and GaO3 clusters.

The results of density functional theory based calculations on Ga3O, Ga3O2, Ga3O3, Ga2O3, and GaO3 clusters are reported here. A preference for planar arrangement of the constituent atoms maximizing the ionic interactions is found in the ground state of the clusters considered. The sequential oxidation of the metal-excess clusters increases the binding energy, but the sequential removal of a metal atom from the oxygen-excess clusters decreases the binding energy. The increase in the oxygen to metal ratio in these clusters is accompanied by increase in both electron affinity and ionization potential. The ionization induced structural distortions in the neutral clusters are relatively small, except those for Ga3O2. In anionic (cationic) clusters, the added (ionized) electron is shared by the Ga atoms, except in the case of GaO3. The vibrational frequencies and charge density analysis reveal the importance of the ionic Ga-O bond in stabilizing the gallium oxide clusters considered in this study.