An aggregation-induced emission-based ratiometric fluorescent chemosensor for Hg(II) and its application in Caenorhabditis elegans imaging.

A chromone-based ratiometric fluorescent probe L2 was developed for the selective detection of Hg(II) in a semi-aqueous solution based on aggregation-induced emission (AIE) and chelation-enhanced fluorescence (CHEF) effect. The probe L2 fluoresced significantly at 498 nm in its aggregated state, and when chelated with Hg(II), the soluble state fluoresced 1-fold higher. In addition, Job's plot reveals that the probe forms a 1:1 stoichiometry complex with Hg(II) with an association constant of 9.10 × 103M-1 estimated by the BH plot. The probe L2 detects Hg(II) down to 22.47 nM without interference from other interfering ions. The FTIR, ESI mass, and DFT-based computational studies investigated the binding mechanism of probe L2 with Hg(II). Taking advantage of its AIE characteristics, the probe L2 was successfully applied for bio-capability analysis in Caenorhabditis elegans (a nematode worm) imaging of Hg(II) in a living model.

Understanding Auger recombination in perovskite solar cells.

Enhanced radiative efficiency, long carrier lifetimes, and high carrier mobilities are hallmarks of perovskite solar cells. Considering this, complete cells experience large nonradiative recombination losses that restrict their VOC considerably below the Shockley-Queisser limit. Auger recombination, which involves two free photo-induced carriers and a trapped charge carrier, is one potential mechanism. Herein, the effects of Auger capture coefficients in mixed-cation perovskites are analyzed employing SCAPS-1D computations. It is demonstrated that VOC and FF are severely decreased with an increase in the acceptor concentration and Auger capture coefficients of perovskites, thus reducing the device performance. When the Auger capture coefficient is increased to 10-20 cm6 s-1 under the acceptor concentration of 1016 cm-3, the performance is drastically lowered from 21.5% (without taking Auger recombination into account) to 9.9%. The findings suggest that in order to increase the efficiency of perovskite solar cells and prevent the effects of Auger recombination, the Auger recombination coefficients should be less than 10-24 cm6 s-1.

Automated Detection and Classification of Telemedical Retinopathy of Prematurity Images.

Background: Retinopathy of prematurity (ROP) is a retinal disorder of low birth weight infants and it is the leading cause of childhood blindness. The capability of wide field digital imaging systems to capture the clinical features of ROP has greatly helped the physicians to assess the severity of ROP and prevent childhood blindness due to ROP. Currently there is a lack of automated systems to assess the severity of ROP to assist the ROP specialist to make treatment decision. Objective: To present an automated detection and classification approach to assess the severity of ROP using wide field telemedical images. Materials and Methods: A total of 160 telemedical ROP (tele-ROP) images were collected out, of which 36 images were Normal, 79 images were Stage 2, and 45 images were Stage 3. Hessian analysis and support vector machine (SVM) classifier have been used to detect and classify the severity of ROP from tele-ROP images. Results: Classified the Normal, Stage 2, and Stage 3 images using SVM. Achieved accuracy of 91.8%, sensitivity of 90.37%, specificity of 94.65%, false positive rate of 5.35%, and false negative rate of 9.63%. Conclusions: The automated approach of detecting and classifying ROP would support pediatric ophthalmologists for early treatment decisions with optimal care.

Influence of Ni Doping in SnO2 Nanoparticles with Enhanced Visible Light Photocatalytic Activity for Degradation of Methylene Blue Dye.

In this article, Nickel doped rutile structure tin oxide (SnO2) nanoparticles have been prepared by simple chemical co-precipitation method and prepared samples were characterized by Powder X-ray Diffraction, Fourier transform infrared Spectroscopy, Microraman analysis, Photoluminescene Spectroscopy, UV-Visible Spectroscopy, Energy dispersive analysis and Field emission scanning electron microscope. XRD studies revealed the single phase tetragonal rutile structure with space group of P42/mnm. The average crystallite size of the particles was decreased from 27 to 22 nm with increasing Ni doping concentration. FTIR spectra confirmed the presence of various bands such as O-H, C-H, Sn-O-Sn. Raman modes Eg, A1g and B2g were assigned at 478, 630 and 740 cm-1 which confirmed the single phase of pure and Ni doped SnO2 nanoparticles. The photoluminescence spectra confirmed that the defect related emissions increased with increasing of Ni concentration. The UV absorption spectra showed that the absorption of the particles decreased with increasing Ni concentration and the band gap values decreased from 3.7 to 3.4 eV. EDX spectra confirmed the presence of Sn, Ni, O in pure and doped samples. The photocatalytic activity of the pure and Ni doped SnO2 nanoparticles were analyzed by using methylene blue dye under visible light irradiation. It is concluded Ni (7%) doped SnO2 nanoparticles have higher degradation efficiency compared to pure SnO2 nanoparticles.

Pulmonary sarcoidosis is associated with high-level inducible co-stimulator (ICOS) expression on lung regulatory T cells--possible implications for the ICOS/ICOS-ligand axis in disease course and resolution.

Sarcoidosis is a granulomatous inflammatory disorder of unknown aetiology. The increased frequency of activated lung CD4(+) T cells with a T helper type 1 (Th1) cytokine profile in sarcoidosis patients is accompanied by a reduced proportion and/or impaired function of regulatory T cells (Tregs ). Here we evaluated the expression of the inducible co-stimulator (ICOS) on lung and blood CD4(+) T cell subsets in sarcoidosis patients with different prognosis, by flow cytometry. Samples from the deep airways were obtained by bronchoalveolar lavage (BAL). We show that Tregs from the inflamed lung of sarcoidosis patients were characterized by a unique ICOS(high) phenotype. High-level ICOS expression was restricted to Tregs from the inflamed lung and was absent in blood Tregs of sarcoidosis patients as well as in lung and blood Tregs of healthy volunteers. In addition, lung Tregs exhibited increased ICOS expression compared to sarcoid-specific lung effector T cells. Strikingly, ICOS expression on Tregs was in particularly high in the lungs of Löfgren's syndrome (LS) patients who present with acute disease which often resolves spontaneously. Moreover, blood monocytes from LS patients revealed increased ICOS-L levels compared to healthy donors. Sarcoidosis was associated with a shift towards a non-classical monocyte phenotype and the ICOS-L(high) phenotype was restricted to this particular monocyte subset. We propose a potential implication of the ICOS/ICOS-L immune-regulatory axis in disease activity and resolution and suggest to evaluate further the suitability of ICOS as biomarker for the prognosis of sarcoidosis.

Methyl ({[(4E)-1,3-dimethyl-2,6-di-phenyl-piperidin-4-yl-idene]amino}-oxy)acetate.

In the title compound, C22H26N2O3, the piperidine ring exhibits a chair conformation. The phenyl rings attached to the piperidine at the 2- and 6-positions have axial orientations. These rings make a dihedral angle of 49.75 (11)°. The amino-oxy acetate group attached at the 4-position has an equatorial orientation. In the crystal, inversion dimers linked by pairs of C-H⋯π inter-actions occur.

(E)-3-Methyl-2,6-di-phenyl-piperidin-4-one O-(3-methyl-benzo-yl)oxime.

In the title compound, C26H26N2O2, the piperidine ring exhibits a chair conformation. The phenyl rings are attached to the central heterocycle in an equatorial position. The dihedral angle between the planes of the phenyl rings is 57.58 (8)°. In the crystal, C-H⋯O inter-actions connect the mol-ecules into zigzag chains along [001].

1-Phenyl-2-[4-(trifluoro-meth-yl)phen-yl]-1H-benzimidazole.

In the title mol-ecule, C(20)H(13)F(3)N(2), the benzimidazole unit is close to being planar [maximum deviation = 0.012 (1) Å] and forms dihedral angles of 31.43 (7) and 61.45 (9)° with the 4-(trifluoromethyl)phenyl and 1-phenyl rings, respectively; the dihedral angle between these rings is 60.94 (10)°. In the crystal, C-H⋯F hydrogen bonds link the mol-ecules into chains along the c-axis direction. The CF(3) group is rotationally disordered with an occupancy ratio of 0.557 (8):0.443 (8) for the F atoms.

2-(4-Meth-oxy-phen-yl)-1-phenyl-1H-benzimidazole.

In the title compound, C(20)H(16)N(2)O, the 1H-benzimidazole ring forms dihedral angles of 48.00 (6) and 64.48 (6)°, respectively with the benzene and phenyl rings, which are inclined to one another by 58.51 (7)°. In the crystal, weak C-H⋯π inter-actions are the only inter-molecular inter-actions present.

1-Phenyl-2-p-tolyl-1H-benzimidazole.

In the title compound, C20H16N2, the benzimidazole ring system forms dihedral angles of 28.50 (7) and 72.44 (7)° with the tolyl and phenyl rings, respectively. In the crystal, mol-ecules are linked into chains along the a-axis direction by weak C-H⋯N inter-actions. The crystal structure also features C-H⋯π inter-actions.

1-(3,5-Dimethyl-phen-yl)-2-(4-fluoro-phen-yl)-1H-phenanthro[9,10-d]imidazole.

In the title compound, C29H21FN2, the phenanthro tricyclic ring system is essentially planar with a maximum deviation of 0.030 (2) Šand makes dihedral angles between of 77.96 (6) and 37.18 (7)° with the dimethyl-phenyl and fluoro-phenyl rings, respectively. The crystal packing features weak C-H⋯π inter-actions involving the dimethyl-phenyl and other phenyl rings.

2-(4-Fluoro-phen-yl)-1-(4-meth-oxy-phen-yl)-1H-phenanthro[9,10-d]imidazole.

In the title compound, C28H19FN2O, the phenanthrene fused with an imidazole ring, constituting an essentially planar tetra-cyclic system [maximum deviation = 0.032 (2) Å], makes dihedral angles of 60.83 (4) and 80.55 (4)° with the fluoro-benzene and meth-oxy-benzene rings, respectively. The dihedral angle between the the meth-oxy-benzene and fluoro-benzene rings is 69.45 (6)°. In the crystal, C-H⋯O hydrogen bonds connect the mol-ecules into infinite strands along the b axis. The crystal structure is further consolidated by C-H⋯π inter-actions.

Glycine-d-tartaric acid (1/1).

In the title co-crystal, C(2)H(5)NO(2)·C(4)H(6)O(6), the gylcine mol-ecule is present in the zwitterion form. In the tartaric acid mol-ecule there is a short intra-molecular O-H⋯O contact. In the crystal, the tartaric acid mol-ecules are linked via pairs of O-H⋯O hydrogen bonds, forming inversion dimers. These dimers are linked via a number of O-H⋯O and N-H⋯O hydrogen bonds involving the two components, forming a three-dimensional network.

1-(4-Meth-oxy-phen-yl)-2-[4-(tri-fluoro-meth-yl)phen-yl]-1H-phenanthro[9,10-d]imidazole.

In the title compound, C29H19F3N2O, a phenanthroline-fused imidazole tetra-cyclic system, the fused benzene rings deviate slightly from the central ring and make dihedral angles with this ring of 3.47 (8) and 3.05 (8)°. The tri-fluoro-methyl-phenyl ring is roughly coplanar with the phenanthroline-fused imidazole tetra-cyclic system [dihedral angle = 11.02 (6)°], while the meth-oxy-phenyl ring is almost perpendicular [dihedral angle = 87.65 (6)°]. There are intra-molecular C-H ⋯π inter-actions involving the meth-oxy-phenyl ring and the central phenanthroline ring, as well as an inter-molecular C-H⋯π inter-action involving the phenanthroline ring. In addition, there is an inter-molecular π-π inter-action involving the central phenanthroline ring and the tri-fluoro-methyl-phenyl ring [centroid-centroid distance = 3.685 (2) Å], as well as C-H⋯N inter-actions linking the mol-ecules into dimers.

1-(4-Methyl-phen-yl)-2-[4-(trifluoro-methyl)phen-yl]-1H-phenanthro[9,10-d]imida-zole.

In the title compound, C29H19F3N2, the tetra-cyclic ring system is essentially planar [maximum deviation from the best plane = 0.076 (1) Å] and makes dihedral angles of 78.10 (5) and 33.71 (4)° with the methyl-phenyl and fluoro-phenyl rings, respectively. An intra-molecular C-H⋯π inter-action occurs. In the crystal, pairs of C-H⋯π inter-actions link inversion-related mol-ecules.

Sulfur deficiency mediated visible emission of ZnS QDs by magnesium dopant and their application in waste water treatment.

The photocatalyst with antimicrobial activity serves as a better candidate material for wastewater treatment, as wastewater contains microbes, hazardous dyes, and heavy metals. Hence, the present study extensively examines the photocatalytic and antibacterial activities against two waterborne bacterial strains, namely Salmonella typhi and Escherichia coli. Pure and Mg-doped ZnS (Mg:ZnS) quantum dots (QDs) were synthesized using a low-cost and simple co-precipitation method. The QDs' structural, surface morphology, chemical purity, and optical characteristics were analyzed through XRD, SEM, EDAX, TEM, UV-visible, and photoluminescence spectra. The incorporation of Mg dopants did not introduce significant alterations to the cubic blende structure of ZnS, nor did it induce substantial changes in the structural parameters. However, the QDs exhibited a slight sulfur deficiency, which was further increased by the presence of Mg dopant. The Mg dopant, due to its dominant compositional effect, reduced the band gap. Several optical emission bands were observed in the UV, violet, blue, and green regions, corresponding to NBE emission, sulfur-related defects, and Zn-related defects. Initially, Mg doping enhanced visible emission related to defects, while NBE emission was suppressed by the Mg dopant. However, increasing the concentration of the Mg dopant led to a slight increase in NBE emission. The Mg dopant enhanced the photocatalytic activity of the QDs, and a strong correlation was found between photocatalytic activity and NBE emission. The presence of the Mg dopant led to an increased rate of ROS-based decolorization by reducing the electron-hole recombination rate.

Thermal, dielectric, mechanical and structural behavior of 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol bulk single crystal.

Applications in both science and industry have received increased attention as a result of bulk single crystals with particular orientations. However, due to the instability of organic crystals at high temperatures and stress, there is an interest in growing good-quality bulk single crystals with stable thermal and mechanical properties. Here, the 2-amino 4-methylpyridinium 4-nitrophenolate 4-nitrophenol (2A4MPPP) crystal was prepared employing a single-wall ampoule and the vertical Bridgman technique. Structure and functional groups were determined by XRD, NMR, and FTIR studies. More importantly, detailed thermal and kinetic properties such as activation energy, frequency factor, rate constant, and Avrami exponent are discussed. The mechanical stability and dielectric studies are also demonstrated for the title compound. According to the single crystal XRD investigation, 2A4MPPP is a member of the orthorhombic crystal system with the Pna21 space group. Through the TGA and DTA analyses, it was confirmed that the compound starts to melt at 98 °C and complete melting occurs at 103.3 °C. The dielectric experiments reveal the crystal's poor dielectric constant and high-frequency dielectric loss. Vickers microhardness investigations show that grown 2A4MPPP belongs to the soft materials group. As a result of these findings, the 2A4MPPP crystal should be well suited for usage in thermomechanical, microelectronic, optical communications, and nonlinear optical applications.

Synthesis, Structure, Morphology, Element composition, Electrochemical, and Optical studies of Zn0.98-XMn0.02CeX Quantum dots.

Quantum dots (QDs) are semiconductors whose size falls in a range between 1 and 10 nm; they are generally known as zero-dimension materials. It finds various applications in optical industries including light-emitting diodes, display technology, imaging, and labelling. ZnS is one of the excellent QDs in its class of II-VI semiconductors. In this paper, It is reported that the preparation of Mn-doped ZnS and Mn, Ce co-doped ZnS QDs using facile co-precipitation technique. XRD and HR-TEM results confirmed the cubic structure, particle size, and phase of the synthesized particles, and the crystallite is measured as âˆ¼ 2 nm. The surface morphology, elemental analysis, and FT-IR spectra revealed the purity of the samples and confirmed the presence of dopants as expected. Cyclic voltammetry studies expressed the electrochemical behaviour of the samples, which increased as a function of Ce3+ doping concentration. UV-visible absorbance and transmittance spectra disclosed the optical characteristics of the samples. A wide band gap (4.02 eV) was received for 2% Ce-doped Zn: MnS QDs. Week Blue and strong yellow emissions were received for 4% Ce-doped Zn:MnS QDs. Whereas, high intensity red-emission was received for 2% Ce-doped Zn:MnS QDs. The different colour emissions are discussed in terms of defects produced.

1-Formyl-c-3,t-3-dimethyl-r-2,c-6-di-phenyl-piperidin-4-one.

In the title compound, C(20)H(21)NO(2), the piperidine ring adopts a distorted boat conformation. The phenyl rings substituted at the 2- and 6-positions of the piperidine ring subtend angles of 86.0 (1) and 67.3 (1)° with the mean plane of the piperidine ring (all six non-H atoms). The crystal packing features C-H⋯O inter-actions.

Influence of Sn4+ ion on band gap tailoring, optical, structural and dielectric behaviors of ZnO nanoparticles.

II-VI semiconductors are being attracted due to excellent optical and electronic behaviors when they utilize for device fabrication. Among II-VI semiconductors, Zinc oxide finds cutting-edge results for various applications with a lack of toxicity. Sn4+ ion incorporated ZnO nanoparticles have been synthesized using a soft chemical route and characterized for the investigation of properties like structural, morphological, elemental, optical and dielectric responses. The prepared ZnO had a hexagonal structure and the particles size reduces by the influence of Sn4+ ion: this reduction rate increases for the increase of doping ratio. The average particles size was estimated within 24-34 nm. TEM, HRTEM and SEM results corroborate the structural aspects noticed using XRPD study. UV-vis study results showed that a blue shift on the optical band gap was received for high doping concentration (10 at.%) of Sn4+. PL peaks were observed in the UV region for 0 at.% and 2 at.% Sn4+ doped ZnO nanoparticles, and the peak position was shifted from UV to violet and blue region for 10 at.% Sn4+ doped ZnO nanoparticles. The dielectric permittivity was reduced due to the addition of Sn4+ ions. The AC conductivity was increased for higher doping concentrations. The Sn4+ ion incorporated ZnO nanoparticles shall be useful for various applications including LED fabrication for blue emission and also it is suitable to act as a buffer material in solar panel.