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We study the morphological distribution of galaxies in some nearby clusters, using the Sloan Digital Sky Survey – Data Release 9 (SDSS-DR9). The segregation between early-type galaxies and late-type ones is investigated in g – r / u – g color space, using the color cut u – r = 2.22. The results are compared with those obtained using a color cut that changes with magnitude. They are found to be consistent, particularly for late-type galaxies. The results obtained by the fixed color-cut criterion are also found to be consistent with those obtained by the inverse concentration index parameter, especially for early-type galaxies. Comparable results are obtained for the stacked sample, whose morphologies, given by the fixed color-cut criterion are compared with the visual morphologies provided by the Galaxy Zoo project. A good degree of consistency is seen, which becomes more evident for late-type galaxies.

The most frequent benign tumor is lipoma. About 1–4% of people have intraoral lipomas. This uncommon case report shows a large cheek lipoma misinterpreted as dental infection. A 14-year-old girl with a right cheek tumor was diagnosed and treated for a dental infection. Multiple imaging examinations complete the diagnosis. A benign lipoma, common in subcutaneous tissues but unusual in the mouth, created the lesion. A histological investigation confirmed lipoma after extraoral excision under general anesthesia utilizing an external flap. The edema did not return after surgery, which restored face symmetry. This case study shows that diagnosing and treating oral and maxillofacial edema requires extensive clinical and radiographic testing. Lipomas should be evaluated in the differential diagnosis of mouth swelling even without usual risk markers to prevent excessive treatments and delays. Surgery is recommended for lipomas since it has a low recurrence and fewer risks. [ABSTRACT FROM AUTHOR]

Background: Five variants of concern (VOCs) of severe acute respiratory syndrome coronavirus 2 (SARS CoV‐2) have been globally recorded including Alpha, Beta, Gamma, Delta, and Omicron. The Omicron variant has outcompeted the other variants including the Delta variant. Molecular screenings of VOCs are important for surveillance, treatment, and vaccination programs. This study aimed to identify VOCs by using rapid inexpensive methods and partial sequencing of the virus's spike gene. Methods: Mutation‐specific rRT PCR probes were used for both D614G and K417N mutations to potentially discriminate between Delta and Omicron variants. These were followed by sequencing of a fragment of spike gene (748 nucleotides), which covers the most notable VOC mutations in the receptor binding domain of SARS CoV‐2. Results: Rapid methods showed that out of 24 SARS CoV‐2 positive samples, 19 carried the N417 mutation, which is present in the Omicron variant. Furthermore, 3 samples carried K417 wildtype, which is present in the Delta variant. Additionally, 2 samples containing both K417 and N417 suggested mixed infections between the two variants. The D614G mutation was present in all samples. Among the 4 samples sequenced, 3 samples carried 13 mutations, which are present in Omicron BA.1. The fourth sample contained the two common mutations (T478K and L452R) present in Delta, in addition to two more rare mutations (F456L and F490S), which are not commonly seen in Delta. Our data suggested that both Omicron variant BA.1 and a novel Delta variant might have circulated in this region that needs further investigations. [ABSTRACT FROM AUTHOR]

Diagnosing of tuberculous arthritis can be challenging due to its insidious onset and non-specific clinical presentation. A high index of suspicion is required for early diagnosis. A 54-year-old butcher was admitted to an orthopedic clinic with complaints of pain, paresthesia and an enlarging mass in the left wrist, which limited finger flexion. Initially the patient was diagnosed with carpal tunnel syndrome (CTS); the patient had no history of tuberculosis (TB), but had direct contact with animals. On clinical examination, a small mass was found in the distal volar region of the forearm and no lymphadenopathy was observed. Despite the diagnosis the patient refused to receive TB treatment. After a period of 4 months, the patient once again exhibited symptoms of CTS. This case highlights the importance of considering TB as a potential etiology for persistent symptoms of carpal tunnel surgery. Early diagnosis and prompt initiation of TB treatment can result in favorable outcomes and can prevent future recurrence. [ABSTRACT FROM AUTHOR]

In the present work, the galaxy luminosity function (LF) has been studied for a sample of seven clusters in the redshift range (0.0 ≲ z ≲ 0.1), within Abell radius (1.5 h-1 Mpc), in the five SDSS passbands ugriz. In each case, the absolute magnitude distribution is found and then fitted with a Schechter function. The fitting is done, using the χ² - minimization method to find the best values of Schechter parameters Ф* (normalization constant), M* (characteristic absolute magnitude), and α (faint-end slope). No remarkable changes are found in the values of M* and α, for any cluster, in any passband. Furthermore, the LF does not seem to vary with such cluster parameters as richness, velocity dispersion, and Bautz-Morgan morphology. Finally, it is found that M* becomes brighter toward redder bands, whereas almost no variation is seen in the value of α with passband, being around (-1.00). [ABSTRACT FROM AUTHOR]

Proton-conducting solid polymer blend electrolytes based on methylcellulose-polyvinyl alcohol:ammonium nitrate (MC-PVA:NH4NO3) were prepared by the solution cast technique. The structural and electrical properties of the samples were examined by X-ray diffraction (XRD), Fourier transform infrared (FTIR), and electrical impedance (EI) spectroscopy. The shifting and change in the intensity of FTIR bands of the electrolyte samples confirm the complex formation between the MC-PVA polymer blend and the NH4NO3 added salt. The observed broadening in the XRD pattern of the doped samples reveals the increase of the amorphous fraction of polymer electrolyte samples. The increase in electrical conductivity of polymer electrolyte samples with increasing salt concentration attributed to the formation of charge-transfer complexes, and to increase in the amorphous domains. A maximum ionic conductivity of about 7.39 × 10−5 S cm−1 was achieved at room temperature for the sample incorporating 20 wt% of NH4NO3. The DC conductivity of the present polymer system exhibits Arrhenius-type dependence with temperature. The decrease in the values of activation energies with increasing salt concentration indicates the ease mobility of ions. The decrease in dielectric constant with increasing frequency was observed at all temperatures. Optical properties such as absorption edge, optical band gap, and tail of localized state were estimated for polymer blend and their electrolyte films. It was found that the optical band gap values shifted towards lower photon energy from 6.06 to 4.75 eV by altering the NH4NO3 salt content. [ABSTRACT FROM AUTHOR]

In the present work, a novel method is exhibited for tuning the surface plasmon resonance (SPR) peaks of silver nanoparticles based on chitosan-Poly(vinyl alcohol) blend polymer nanocomposites. Silver nanoparticles were synthesized by in situ method through the chitosan host polymer. The absence of crystalline peaks of PVA in the blend system indicated the occurrence of miscibility between CS and PVA polymers. The UV-vis spectra of CS:AgNt samples shows SPR bands with weak intensity. Obvious tuning in SPR peaks of silver nanoparticles occurred when different amounts of PVA polymer incorporated to the CS:AgNt system. The appearance of distinguishable crystalline peaks of Ag° nanoparticles at 2ϑ = 38.6° and 2ϑ = 44.2° in the blend system reveals the role of polymer blending in the enhancement of SPR peaks of silver nanoparticles. Silver nanoparticles synthesized in this work with enhanced SPR peaks are important in various applications and areas such as optoelectronic devices. The TEM images show dispersed silver nanoparticles. The dielectric constant of PVA is higher than that of chitosan. The result of dielectric constant study validates the Mie model which reveals the fact that the dielectric constant of the surrounding material has a great effect on the SPR peak intensity of nanoparticles. [ABSTRACT FROM AUTHOR]

The optoelectronic parameters of tris (8-hydroxyquinoline) gallium (Gaq3) films were tuned by means of post-deposition thermal annealing under nitrogen gas. Nanostructure evolution was seen to play a vital role in the variation of the optoelectronics parameters of these films. The results showed an increased refractive index from 1.53 to ultra-high refractive index of 5.45, along with a maximized dielectric constant of 13.92 and optical conductivity of 56.31 S/cm when the films were annealed at 235 °C. At higher annealing temperature of 255 °C, a decreased trend was noticed for the aforementioned optoelectronic parameters and the grown amorphous nanorods were completely degraded, which has led to the formation of crystalline portions. The results were interpreted in terms of molecular packing density and structural variations. The investigated Gaq3 films were seen to obey Wemple-DiDomenico single oscillator model to provide information regarding the band gap and its strength. The achieved results are greatly important for the application of OLED displays technology and their performance improvement. [ABSTRACT FROM AUTHOR]

Solid polymer electrolytes (SPEs) based on polyvinyl alcohol (PVA) and sodium triflate (NaTf) have been prepared by solution cast technique. X-ray diffraction was performed for structural analysis. The decrease of intensity of crystalline peaks of PVA upon addition of NaTf salt reveals the increase of amorphous domain in SPEs. Impedance plots (Zi vs. Zr) shows that the electrolyte samples have a smaller bulk resistance. The highest achieved room temperature DC conductivity is 7.39 × 10 S/cm for the sample incorporated with 30 wt% of NaTf. The influence of lattice energy of sodium salts on DC conductivity is discussed. It was appeared that the lattice energy of salts significantly affects the conductivity behavior of polymer electrolytes. High DC conductivity can be achieved for polymer electrolytes incorporated with low lattice energy salts. The pattern of DC ionic conductivity against 1000/T is follows Arrhenius equation. The highest conducting composition has the lowest activation energy (0.109 eV). The DC conductivities calculated from the complex impedance plots are close to those obtained from the plateau region of AC conductivity spectra. Transport parameters such as density of mobile ions (Na), mobility, and diffusion coefficient were determined for the samples using the Rice and Roth models. The dielectric analysis suggests non-Debye type of relaxation of ions in the present work. [ABSTRACT FROM AUTHOR]

In this research work, numerical simulations are performed to correlate the photovoltaic parameters with various internal and external factors influencing the performance of solar cells. Single-diode modeling approach is utilized for this purpose and theoretical investigations are compared with the reported experimental evidences for organic and inorganic solar cells at various electrical and thermal conditions. Electrical parameters include parasitic resistances (Rs and Rp) and ideality factor (n), while thermal parameters can be defined by the cells temperature (T). A comprehensive analysis concerning broad spectral variations in the short circuit current (Isc), open circuit voltage (Voc), fill factor (FF) and efficiency (η) is presented and discussed. It was generally concluded that there exists a good agreement between the simulated results and experimental findings. Nevertheless, the controversial consequence of temperature impact on the performance of organic solar cells necessitates the development of a complementary model which is capable of well simulating the temperature impact on these devices performance. [ABSTRACT FROM AUTHOR]

In this study, the role of ion dissociation on formation of silver nanoparticle and DC conductivityin PVA:AgNO3 based solid polymer electrolyte has been discussed in detail. Samples of silver ion conducting solid polymer electrolyte were prepared by using solution cast technique. Absorption spectroscopy in the ultraviolet-visible (UV-Vis) spectral region was used to investigate the formation of silver nanoparticles. Broad and sharp peaks due to plasmonic silver nanoparticles subjected to ion dissociation have been observed. The influence of dielectric constant on the intensity of surface plasmonic resonance (SPR) peaks attributed to silver nanoparticles was discussed. From impedance plots, the diameter of high frequency semicircle was found to be decreased with increasing salt concentration. The DC conductivity in relation to the dielectric constant was also explained. From the AC conductivity spectra, the dc conductivity was estimated to be close to that calculated from the bulk resistance. The temperature dependence of the DC conductivity was studied and found to follow Arrhenius equation within two distinguished regions. The AC conductivity at different temperatures has been studied to comprehend the ion conduction mechanism. The AC conductivity against frequency was found to obey the universal power law of Jonscher. Three distinct regions were recognized from the spectra of AC conductivity. The frequency exponent (S) was calculated for the dispersive region of the measured AC conductivity spectra. Various models were discussed to explain the behavior of S value with temperature. The behavior of S value with temperature was then used to interpret the DC conductivity pattern against 1000/T. Finally, from the comparison of calculated activation energy (Ea) and maximum barrier height (Wm), deep insights into ion conduction mechanism could be grasped. [ABSTRACT FROM AUTHOR]

ABSTRACT In this article, a novel approach is presented for the preparation of small band-gap polymer composites. The intensity of the surface plasmon resonance (SPR) peak increased from 0.64 to 3.2 for the chitosan-silver nitrate sample containing 1 wt % titanium dioxide (TiO2). In the cases of 3 and 5 wt % added TiO2 particles, the SPR peak disappeared. A wide shift of the absorption coefficient from 4.36 to 0.93 eV was observed. The smallest optical band gap of about 0.98 eV was achieved for the sample containing 3 wt % TiO2 filler. The wide shift in the optical band gap was interpreted on the bases of the formation of metal-induced gap states between the metallic silver particles and the TiO2 structure. A novel approach was achieved that was an alternative method to Tauc's semi-empirical model for band-gap estimation. The optical dielectric loss parameter for the band-gap study was easily calculated and analyzed, whereas it unfolded a deep knowledge from the physics point of view. The established quantum mechanical expression revealed a strong relationship between the energy band gap and the optical dielectric loss parameter. The scanning electron microscopy results show the leakage of white aggregated silver particles and distinguishable intense peaks of metallic silver particles between 3 and 3.3 keV appearing in the energy-dispersive X-ray spectrum. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44847. [ABSTRACT FROM AUTHOR]

In this paper, the sample preparation of polymer nanocomposites based on methyl cellulose (MC) with small optical bandgaps has been discussed. Copper monosulfide (CuS) nanoparticles have been synthesized from the sodium sulphide (Na2S) and copper chloride (CuCl2) salts. Distinguishable localized surface resonance plasmon (LSRP) absorption peaks for CuS nanoparticles within the 680–1090 nm scanned wavelength range were observed for the samples. An absorption edge (Ed) was found to be widely shifted to a lower photon energy region. A linear relationship between the refractive index of the samples and the CuS fraction was utilized to describe the distribution of the particle. The optical bandgap of MC was reduced from 6.2 to 2.3 eV upon the incorporation of 0.08 M of CuS nanoparticles. The optical dielectric loss, as an alternative method, was used successfully to estimate the optical bandgap. Moreover, the electronic transition type was identified by using Tauc’s extrapolation method. The plots of the optical dielectric constant and energy bandgap as a function of the CuS concentration were utilized to examine the validity of the Penn model. For the nanocomposite samples, the Urbach energy was found to be increased, which can be evidence for a large possible number of bands-to-tail and tail-to-tail transitions. However, from the X-ray diffraction (XRD) analysis, it was also found that the synthesized CuS nanoparticles disrupted the crystallinity phase of the MC polymer. Finally, fourier transform infrared (FTIR) spectroscopy for the samples was also performed. Significant decreases of transmittance intensity as well as band shifting in the FTIR spectra were observed for the doped samples. [ABSTRACT FROM AUTHOR]

Chitosan (CS) films doped with sodium triflate (NaTf) were prepared by the solution cast technique. The structural and morphological behaviors of the samples were examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The XRD patterns were deconvoluted to estimate the degree of crystallinity of the samples. The SEM micrograph showed the crystalline structure of the sample contained 50 wt % of NaTf salt. The disappearance of broad peaks of chitosan at 2θ ≈ 21° and 2θ ≈ 32° confirmed the occurrence of ion association at 50 wt % of NaTf salt. In impedance plots, a low frequency spike region and a high frequency semicircle, were distinguishable for low salt concentrations. The highest ambient temperature direct current (DC) electrical conductivity obtained for CS:NaTf was found to be 2.41 × 10−4 S/cm for the sample containing 40 wt % of NaTf salt. The role of lattice energy of salts on DC ionic conductivity was also discussed. The temperature dependence of DC conductivity was found to follow the well-known Arrhenius relationship. From the alternating current (AC) conductivity spectra, three distinct regions were recognized for the samples with NaTf salt concentration ranging from 10 wt % to 30 wt %. The plateau region of AC spectra was used to estimate the DC conductivity. [ABSTRACT FROM AUTHOR]

In this work an innovative experimental method has been proposed to estimate the optical bandgap and determine the types of electronic transitions. Solid polymer blend electrolyte films based on PVA:PEO have been prepared by the well known solution cast technique. It was observed that the absorption increased with increasing aluminum salt concentration and shifted to higher wavelengths. Shifting of absorption edge to lower photon energy indicates a good reactivity between the polymer blends and the aluminum salt which in turn the energy band gap decrement is expected. An increase in refractive index for the doped samples has been observed. The miscibility between the aluminum salt and the polymer blends can be well understood from the linear relationship between the refractive index and the volume fraction of the added salt. The increase of extinction coefficient at high wavelengths was observed. The optical band gap measured from the plots of (αhυ)^ versus photon energy (hυ) was compared to that determined from the optical dielectric loss. From the results of the present work it is understood that in order to avoid the plotting of many figures based on Tauc model, optical dielectric loss must be studied. Further research works are required to satisfy that the optical dielectric loss can be used to estimate the band gap and identify the types of electronic transition. The Urbach energy was found to increase with increasing aluminum salt concentration. [ABSTRACT FROM AUTHOR]

The polymer composite films of Poly(methyl methacrylate) (PMMA) doped with different wt% of Silicon powder (Si) were prepared using solution casting technique, to investigate the effect of Si content on the optical characterization of PMMA matrix. It is found that the fundamental optical absorption edge of PMMA is shifting toward lower energy with the increase of the Si content, resulting the decreases in the optical band gap of PMMA monotonously. The optical constants of PMMA:Si composite, such as the optical absorption coefficient, refractive index, extinction coefficient and complex dielectric constant, are greater than those of pure PMMA. The energy dispersion parameters of PMMA:Si composite versus Si wt% have been determined and explained using Wemple-DiDomenico single oscillator model. The linear relationship between the static refractive index and Si volume fraction reveal the well-dispersed Si powder in the PMMA host polymer matrix. The SEM micrographs also revealed the uniform dispersion of Si powder in PMMA matrix. The observed improve in the optical properties of PMMA:Si films denote that this composite could be used in UV-blocking contact lenses and optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this paper composite materials, based on polymer blends of polyvinyl alcohol (PVA): polyvinyl pyrrolidone (PVP) with small optical band gap, has been studied. Silver sulfide (Ag 2 S) semiconductor particles have been synthesized in PVA:PVP blend host polymer, using in situ method. X-ray diffraction (XRD) analyses and Fourier transform infrared (FTIR) spectroscopy for the composite samples were carried out. From the XRD pattern, distinguishable crystalline peaks caused by the Ag 2 S semiconductor particles were observed. From the result of FTIR spectroscopy, the intensity of the FTIR bands were shifted and increased, revealing the occurrence of interactions between the PVA:PVP blend system and Ag 2 S particles. The composite samples were found to exhibit absorption spectra that cover UV–visible to near infrared regions. The absorption edge was found to be 5 eV for pure PVA:PVP system and shifted to 1.15 eV for incorporated PVA:PVP with 3 M of Ag 2 S. The refractive index was also evaluated for the samples and observed to be increased from 1.15 to 1.52 as doping increased to the highest. A linear relationship between the refractive index and the filler fraction has been reported. Theoretical discussion of optical dielectric loss, which is a crucial parameter for the band gap estimation, was given. The achieved results reveal that spectra of the optical dielectric loss (ɛ i ) can be used to study the band gap structure and Tauc's model can be important in determining the types of electronic transition. The optical band gap was found to decrease from 5.2 eV for the pure PVA:PVP to 1.1 eV for doped PVA:PVP with 3 M of Ag 2 S. Such reduction can be associated with the increase of optical dielectric constant. Finally, the correlation between optical dielectric constant and density of states was discussed. [ABSTRACT FROM AUTHOR]

In this paper, the sample preparation of polymer nanocomposites based on methyl cellulose (MC) with small optical bandgaps has been discussed. Copper monosulfide (CuS) nanoparticles have been synthesized from the sodium sulphide (Na₂S) and copper chloride (CuCl₂) salts. Distinguishable localized surface resonance plasmon (LSRP) absorption peaks for CuS nanoparticles within the 680⁻1090 nm scanned wavelength range were observed for the samples. An absorption edge ( E d ) was found to be widely shifted to a lower photon energy region. A linear relationship between the refractive index of the samples and the CuS fraction was utilized to describe the distribution of the particle. The optical bandgap of MC was reduced from 6.2 to 2.3 eV upon the incorporation of 0.08 M of CuS nanoparticles. The optical dielectric loss, as an alternative method, was used successfully to estimate the optical bandgap. Moreover, the electronic transition type was identified by using Tauc's extrapolation method. The plots of the optical dielectric constant and energy bandgap as a function of the CuS concentration were utilized to examine the validity of the Penn model. For the nanocomposite samples, the Urbach energy was found to be increased, which can be evidence for a large possible number of bands-to-tail and tail-to-tail transitions. However, from the X-ray diffraction (XRD) analysis, it was also found that the synthesized CuS nanoparticles disrupted the crystallinity phase of the MC polymer. Finally, fourier transform infrared (FTIR) spectroscopy for the samples was also performed. Significant decreases of transmittance intensity as well as band shifting in the FTIR spectra were observed for the doped samples., Competing Interests: The authors declare no conflict of interest