Evaluation of Association between Maxillary Posterior Teeth Periapical Pathologies and Maxillary Sinus Mucosal Changes-A Cone-Beam Computed Tomography (CBCT) Study.

Introduction Odontogenic infections are one of the common causes of maxillary sinusitis. With the close proximity of the roots of maxillary posterior teeth to the sinus floor, the infection may spread into the sinus causing sinus mucosal thickening. This study aims to evaluate the association between maxillary posterior teeth periapical pathologies and maxillary sinus mucosal changes using cone-beam computed tomography (CBCT) images. Methods One-hundred six maxillary posterior teeth with periapical lesions were included in this study and were assessed using CBCT images by two maxillofacial radiologists. The proximity of the roots to the sinus floor, the proximity of the top edge of the periapical lesion to the sinus floor, and the sinus mucosal changes associated with the periapical lesions were studied. The size of the periapical lesion was measured and scored using CBCT periapical index. Mucosal thickening more than 2 mm was considered pathological and the type, pattern, and severity of mucosal thickening were assessed. Data were analyzed using chi-squared tests at a level of significance set at p -value less than 0.05. Results Among the 106 teeth with periapical lesions, 99 teeth (93.4%) revealed the presence of maxillary sinus mucosal thickening. The prevalence of mucosal thickening increased significantly with the presence of cortical bone destruction, the close proximity of the root, and the periapical lesion to the sinus floor. The generalized type of mucosal thickening was more prevalent with larger periapical lesions and a significant increase in the severity of the thickening was observed closer spatial relationship of the root to the sinus floor. Conclusion Periapical pathologies of maxillary posterior teeth often cause sinus mucosal thickening. The early diagnosis and management of these pathologies will be helpful in preventing the spread of infection into the maxillary sinus.

Domain-wall dark pulse generation with SMF-GIMF-SMF structure as artificial saturable absorber.

We experimentally demonstrated the generation of domain-wall dark pulse in an Erbium-doped fiber laser using the combination of a 10 cm graded index multimode fiber sandwiched by single mode fibers as artificial saturable absorber. The interaction of phase difference in grade index multimode fiber allowed the stable dual-wavelength oscillation in the cavity. The dual-wavelength centered at 1567.2 nm and 1569.4 nm produces the topological defect in temporal domain and achieved a dark pulse formation with repetition rate of 21.5 MHz. The highest average pulse energy is calculated as 769.6 pJ with pulse width of 5 ns. Throughout the operating pump power range, the average pulse energy and output power increase linearly, with R2 of 0.9999 and achieved the laser efficiency of 9.33%. From the measurement in frequency domain, the signal-to-noise ratio is measured as 49 dB. As compared to reported DW dark pulse works, the proposed structure only required a short length of multimode fiber, which allowed the domain-wall dark pulse to achieve higher pulse repetition rate. The venture of domain wall dark pulse is potentially to pave the foundation toward sustainable industrial growth.

Herniation of Parotid Gland into Masseter Muscle: A Rare Case Report.

A herniation is the abnormal protrusion of an organ or other body structure through a defect or natural opening in a covering membrane, muscle, or bone. The parotid gland is the largest of the salivary glands, which is situated below the external acoustic meatus and overlaps the masseter muscle anteriorly. In this rare case report, a 35 years old female patient complained of pain in the cheek region for 3 years and gave a history of pain aggravating while having sour food. On palpation, multiple nodules were found bilaterally in the cheek area which was tender. Ultrasonography of the masseter and parotid region showed herniation of the lower lobe of the parotid gland into the masseter muscle which is 1 cm on the right side and 0.8 cm on the left side. The findings obtained from ultrasound images were further confirmed with Magnetic Resonance Imaging (MRI).

Conservative Approach for Treatment of Isolated Mandibular Fractures, the Adaptations During COVID 19 Pandemic.

Background: The ongoing COVID 19 pandemic brought about a sudden disruption to the way medical services are rendered in our country. Management of maxillofacial injuries, especially isolated mandibular fractures by surgical methods, became near impossibility because of the restrictions and other concerns related to the pandemic. Methods: The individuals who suffered isolated mandibular fracture because of trauma were included, to undergo conservative treatment methods with adaptations for the pandemic. Individuals with multiple bone fractures were excluded, and the selected patients were given the choice to opt out from this treatment plan. We followed a more conservative approach with adaptations, which we have discussed in this article. Result: The fracture healing for all the patients was as expected, and none of our team members got infected with this virus from exposure to patients. Conclusion: The adaptations helped in limiting the possible exposure of patients, relatives and health care providers to the virus and addressed other pressing concerns related to this pandemic. We present the guideline that we formulated in our unit, which we used to manage the patients who reported to us with isolated mandibular fractures during the ongoing pandemic.

Investigation of the Photoluminescence and Nonlinear Optical Properties of Ce2O3-TiO2 Nanocomposites.

This paper reports the photoluminescence and nonlinear optical (NLO) properties of Ce2O3-TiO2 nanocomposites synthesized via sol-gel process with different concentrations of cerium. The physical characterization studies by means of XRD indicated for the successful incorporation of Ce into the lattice of TiO2, while the UV-visible spectra for an absorption edge shift of TiO2 to the higher wavelength side following the Ce addition, and FESEM analysis for the morphology and particles sizes of the synthesized materials. On testing of the photoluminescence properties recorded through time-resolved fluorescence (TCSPC) technique, a decrease in the intensity of TiO2 with that of increased Ce concentration was observed and is due to an escalation in the number of oxygen vacancies. Further, the observation NLO properties for Ce2O3-TiO2 was done by a Z-scan technique of 5ns continuous wave (cw) laser at 532 nm, where the involvement of active mechanisms in the nonlinear refraction and nonlinear absorption are due to the saturable absorption (SA) and nonlinear thermal effects.

The exploration of the crystal nucleation parameters and physico-chemical analysis of a single crystal: 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine.

This paper discusses the structural orientations and the physico-chemical properties of a single crystal of 2-amino-4,6-dimethoxypyrimidinium hydrogen (2R,3R)-tartrate 2-amino-4,6-dimethoxypyrimidine (2ADT). The experimental investigation of the properties of the compound improves the potential for the utilization of the crystalline compound in the fabrication of optical limiting and nonlinear optical devices. For the growth process, an organic nonlinear optical crystal of 2ADT is synthesized conventionally at varying molar concentrations to achieve an excellent yield. The structural orientations and refinements of the compound are identified and discussed with reference to a single crystal X-ray diffraction study and its supporting computations. The results of the experimental analysis via UV-vis-NIR spectrometry and a z-scan setup with a laser beam source are used in an in-depth discussion on the linear and nonlinear optical properties of the crystal together with its damage threshold induced by a Nd:YAG laser beam at 1064 nm. With optical transparency of 55% in the entire visible region, a lower cut-off wavelength at 228 nm, and a bandgap at 5.2 eV, the crystal was demonstrated to be suitable for use in optical device fabrication. The thermogravimetrically assessed thermal stability of 2ADT was examined up to 147 °C. In addition, the thermodynamic parameters responsible for activation reactions are also discussed because these give information about the material's thermal behavior. An optical limiting study revealed that the transmitted output power increases linearly with the input power at about 1.89 mW cm-2.

Synthesis, growth, optical, mechanical, thermal, dielectric and third order nonlinear optical properties of cyclohexylamine derivative single crystals.

The materials of Cyclohexylamine with 1,5-naphthalenedisulfonic acid and 3,5-dinitrosalicylic acid were used to synthesize the bis(cyclohexylammonium)-1,5-naphthalenedisulfonate (CA15NS) and bis(cyclohexylammonium)-3,5-dinitrosalicylate (CA35NS) compounds and single crystals of these compounds were grown successfully by low temperature solution growth technique. Crystal systems of the samples were identified for both the samples of CA15NS and CA35NS by the obtained unit cell parameters of the grown crystals which is determined by single crystal X-ray diffraction (SCXRD) analysis, the crystals of CA15NS and CA35NS are crystallized in monoclinic crystal structures. The powder X-ray diffraction (PXRD) analysis also was carried out for the title samples. The formations of the charge-transfer functional groups and the modes of vibrations of CA15NS and CA35NS have been confirmed by FT-IR and FT-Raman spectral analyses. The UV-Vis-NIR spectrum was carried out to find the optical behavior of the prepared crystals. The crystal of CA15NS has 232 nm and CA35NS has 207 nm as cut-off wavelength. The influences of mechanical and dielectric behavior in the crystals of CA15NS and CA35NS were investigated by means of Vickers microhardness test and dielectric study, respectively. By the thermo gravimetric analyses, the stability of the materials have been estimated for the title samples. Third order nonlinear optical study has also been studied by Z-scan technique.

Supramolecular cocrystals of O-H...O hydrogen-bonded 18-crown-6 with isophthalic acid derivatives: Hirshfeld surface analysis and third-order nonlinear optical properties.

Two cocrystals of 18-crown-6 with isophthalic acid derivatives, 5-hydroxyisophthalic acid and trimesic acid, have been successfully grown by the slow evaporation solution growth technique. Crystal structures of (18-crown-6)·6(5-hydroxyisophthalic acid)·10(H2O) (I) and (18-crown-6)·2(trimesic acid)·2(H2O) (II) elucidated by single crystal X-ray diffraction reveal that both cocrystals pack the centrosymmetric triclinic space group P{\overline 1}. The molecules are associated by strong/weak hydrogen bonds, π...π and H...H stacking interactions. Powder X-ray diffraction analyses, experimental and simulated from single-crystal diffractogram data have been matched. The vibrational patterns in FT-IR spectra are used to identify the functional groups. The band gap energy is estimated by the application of the Kubelka-Munk algorithm. Hirshfeld surfaces derived from X-ray diffraction analysis reveal the type of molecular interactions and their relative contributions. The constructed supramolecular assembly of crown ether cocrystal is thoroughly described. Both cocrystals exhibit a significant third-order nonlinear optical response and it is observed that (I) possesses a significant first-order molecular hyperpolarizability whereas it is negligible for (II).

Influence of gold nanoparticles on the nonlinear optical and photoluminescence properties of Eu2O3 doped alkali borate glasses.

Alkali borate glasses activated with trivalent europium ions and rooted with gold (Au) nanoparticles (NPs) were synthesised through a melt quenching process involving a selective thermochemical reduction and their applicability as photonic materials was assessed in detail. Non-linear optical (NLO) measurements were performed using a Z-scan approach in the wavelength range of 700-1000 nm. The open aperture Z-scan signatures for the Eu3+-containing glasses embedded with and without the Au NPs established a reverse saturable absorption (RSA) at all of the studied wavelengths ascribed to the two-photon absorption (2PA). Surprisingly, the nonlinear optical absorption switched to a saturable absorption (SA) with an increase in the concentration of AuCl3. With the incorporation of the Au NPs, the UV excited photoluminescence (PL) intensity of the Eu3+-doped glasses increased first as a consequence of the local field enhancement by the Au NPs, and subsequently decreased at a higher concentration of AuCl3 due to the reverse energy transfer from the Eu3+ ion to the Au0 NPs. The electronic polarization effect of the host glass enhanced the 5D0→7F4 transition intensity on the incorporation of the gold NPs owing to the gold NP-embedded glasses showing a deep-red emission. The NLO and PL studies suggested that the investigated glasses containing a 0.01 mol% of AuCl3 is practically appropriate for photonic applications.

Low power optical limiting studies of copper doped lithium tetraborate nanoparticles.

The copper doped lithium tetraborate (LTB:Cu) nanoparticles were synthesized by sol-gel method and characterized by XRD (tetragonal structure) and by FESEM (sphere-like nanoparticle). UV-Vis studies show that there is no strong absorption in the visible region. In the luminescence spectrum, the emission peak at 370 nm reveals the presence of Cu+ in LTB lattice. The relative powder second harmonic generation efficiency of pure and doped LTB is equal to the standard NLO material, KDP. The nonlinear optical parameters of LTB:Cu nanoparticles say, nonlinear refractive index, nonlinear absorption coefficient and third order nonlinear optical susceptibility were determined to be of the order of 10(-8)cm2/W, 10(-2) cm/W and 10(-5) esu, respectively. The optical power limiting behavior of the samples were studied by Z-scan technique with (532 nm, 50 mW) Nd:YAG laser and the limiting threshold values are found to be 22.7 mW for 0.01 M and 24.9 mW for 0.03 and 0.05 M LTB:Cu nanoparticles.

χ(3) Measurement and optical power limiting behavior of manganese doped lithium tetraborate nanoparticles.

Manganese doped Li2B4O7 nano crystallites were prepared by chemical method and characterized by XRD, FTIR, UV and fluorescence spectra. FESEM reveals that the particles are coagulated and the particle size is in the range of 50-107 nm. Bands appear at 682-769 cm(-1) corresponds to the bending of B-O linkage in borate network. Nonradiative energy transfer process is observed from fluorescence spectrum. UV-Vis studies show the samples are completely transparent in the visible region and having absorption peaks (234 and 276 nm) in UV regime. The measured second harmonic generation values are 0.9 times KDP. The nonlinear optical parameters such as nonlinear refractive index, n2 (10(-8) cm(2)/W), nonlinear absorption, ß (10(-2) cm/W) and nonlinear optical susceptibility, χ(3) (10(-5) esu) are estimated using a Nd:YAG laser (532 nm, 50 mW).

Ethylenediaminium di(4-nitrophenolate): a third order NLO material for optical limiting applications.

Single crystals of ethylenediaminium di(4-nitrophenolate) [EDA4NP] were grown by slow evaporation solution growth technique using ethanol as solvent at constant temperature. It crystallizes in monoclinic centrosymmetric space group C2/c with cell dimension a=11.326Ǻ, b=7.264Ǻ, c=20.036Ǻ; ß=93.55°. Fourier Transform Infra Red (FT-IR) spectrum was recorded to identify various functional groups present in EDA4NP. Nuclear Magnetic Resonance (NMR) spectral studies were performed to confirm the functional groups. Thermogravimetric analysis and differential thermal analysis showed that the compound melts at 142.9°C. The material possesses a wide optical transparency window in the visible and near IR region (500-1200nm). The nonlinear refractive index, nonlinear absorption coefficient and third-order nonlinear susceptibility of EDA4NP were estimated to be n2=5.46×10(-8)cm(2)W(-1), ß=0.65×10(-3)cmW(-1) and χ((3))=2.96×10(-6)esu respectively. The limiting behavior observed with the sample is attributed mainly to nonlinear refraction.

Growth and characterization of organic material 4-dimethylaminobenzaldehyde single crystal.

The organic material 4-dimethylaminobenzaldehyde single crystals were grown by slow evaporation technique. The grown crystal was confirmed by the single crystal and powder X-ray diffraction analyses. The functional groups of the crystal have been identified from the Fourier Transform Infrared (FTIR) and FT-Raman studies. The optical property of the grown crystal was analyzed by UV-Vis-NIR and photoluminescence (PL) spectral measurements. The thermal behavior of the grown crystal was analyzed by thermogravimetric (TG) and differential thermal analyses (DTA). Dielectric measurements were carried out with different frequencies by using parallel plate capacitor method. The third order nonlinear optical properties of 4-dimethylaminobenzaldehyde was measured by the Z-scan technique using 532 nm diode pumped continuous wave (CW) Nd:YAG laser.

Nonlinear studies of acid fuchsin dye in liquid and solid media.

Solid-state dye-doped polymers are attractive alternative to the conventional liquid dye solutions. In this paper, nonlinear properties of the dye Acid Fuchsin has been studied. The third-order nonlinear optical properties of Acid Fuchsin dye in 1-butanol and dye-doped polymer film were measured by the Z-scan technique using 532 nm diode pumped Nd:Yag laser. This material exhibits negative optical nonlinearity. The dye at 0.4 mM concentration exhibited nonlinear refractive coefficient (n(2)=-8.72 x 10(-8) and -10.308 x 10(-8) (cm(2)/W) in liquid and solid media, respectively), nonlinear absorption coefficient (beta=-7.69 x 10(-4) and -8.294 x 10(-4)cm/W in liquid and solid media, respectively) and susceptibility (chi(3)=4.33 x 10(-6) and 5.13 x 10(-5)esu in liquid and solid media, respectively). These results show that Acid Fuchsin dye has potential applications in nonlinear optics.

Nonlinear studies of Pararosanilin dye in liquid and solid media.

Solid-state dye-doped polymers are attractive alternative to the conventional liquid dye solutions. In this paper, nonlinear properties of the dye Pararosanilin has been studied. The third-order nonlinear optical properties of Pararosanilin dye in 1-butanol and dye-doped polymer film were measured by the Z-scan technique using 532 nm diode pumped Nd:Yag laser. This material exhibits negative optical nonlinearity. The dye at 0.4 mM concentration exhibited nonlinear refractive coefficient (n(2) = -6.8 x 10(-8) and -7.11 x 10(-8) (cm(2)/W) in liquid and solid media, respectively), nonlinear absorption coefficient (beta = -7.7 x 10(-4) and -7.93 x 10(-4)cm/W in liquid and solid media, respectively) and susceptibility (chi((3))=3.38 x 10(-6) and 3.53 x 10(-5)esu in liquid and solid media, respectively). These results show that Pararosanilin dye has potential applications in nonlinear optics.