Physical properties and their corresponding changes of mixing for the ternary mixture acetone + n-hexane + water at 298.15 K

Experimental density and the refractive index of the ternary mixture acetone + n-hexane + water, and their binary systems were experimentally measured and correlated at 298.15 K and atmospheric pressure. A maximum in refractive indices has been observed for the acetone + water system while the excess molar volume and the molar refraction change are all negative. For the mixture acetone + n-hexane, the excess molar volume is always positive and the molar refraction change of mixing showed a S-shaped dependence on acetone composition. The excess molar volumes and molar refraction changes of mixing were correlated using the Redlich-Kister expression and Cibulka equation. The coefficients and standard deviation between the experimental and fitted values were estimated. Good agreement between both results was obtained.     

Optical Spectroscopy as a Method for Skin Cancer Risk Assessment

Skin cancer is the most prevalent cancer, and its assessment remains a challenge for physicians. This study reports the application of an optical sensing method, elastic scattering spectroscopy (ESS), coupled with a classifier that was developed with machine learning, to assist in the discrimination of skin lesions that are concerning for malignancy. The method requires no special skin preparation, is non‐invasive, easy to administer with minimal training, and allows rapid lesion classification. This novel approach was tested for all common forms of skin cancer. ESS spectra from a total of 1307 lesions were analyzed in a multi‐center, non‐randomized clinical trial. The classification algorithm was developed on a 950‐lesion training dataset, and its diagnostic performance was evaluated against a 357‐lesion testing dataset that was independent of the training dataset. The observed sensitivity was 100% (14/14) for melanoma and 94% (105/112) for non‐melanoma skin cancer. The overall observed specificity was 36% (84/231). ESS has potential, as an adjunctive assessment tool, to assist physicians to differentiate between common benign and malignant skin lesions.     

Monotone and maximal monotone affine subspaces

Affine monotone and maximal monotone subspaces are characterized.     

Study of Nanocrystalline BiMnO3‐‐PbTiO3: Synthesis,Structural Elucidation,and Magnetic Characterization of the Whole Solid Solution

In the last ten years, the study and the search for new multiferroic materials have been a major challenge due to their potential applications in electronic technology. In this way, bismuth‐containing perovskites (BiMO₃), and particularly those in which the metal M position is occupied by a magnetically active cation, have been extensively investigated as possible multiferroic materials. From the point of view of synthesis, only a few of the possible bismuth‐containing perovskites can be prepared by conventional methods but at high pressures. Herein, the preparation of one of these potential multiferroic systems, the solid solution xBiMnO₃‐(1?x)PbTiO₃ by mechanosynthesis is reported. Note that this synthetic method allows the oxides with high x values, and more particularly the BiMnO₃ phase, to be obtained as nanocrystalline phases, in a single step and at room temperature without the application of external pressure. These results confirm that, in the case of Bi perovskites, mechanosynthesis is a good alternative to high‐pressure synthesis. These materials have been studied from the point of view of their structural characteristics by precession electron diffraction and magnetic property measurements.     

Luminescence rigidochromism and redox chemistry of pyrazolate-bridged binuclear platinum(II) diimine complex intercalated into zirconium phosphate layers

The direct intercalation of a pyrazolate-bridged platinum(II) bipyridyl dimer ([{Pt(dmbpy)(μ-pz)}(2)](2+); dmbpy = 4,4'-dimethyl-2,2'-bipyridine, pz(-) = pyrazolate) within a zirconium phosphate (ZrP) framework has been accomplished. The physical and spectroscopic properties of [{Pt(dmbpy)(μ-pz)}(2)](2+) intercalated in ZrP were investigated by X-ray powder diffraction and X-ray photoelectron, infrared, absorption, and luminescence spectroscopies. Zirconium phosphate layers have a special microenvironment that is capable of supporting a variety of platinum oxidation states. Diffuse reflectance spectra from powders of the blue-gray intercalated materials show the formation of a low-energy band at 600 nm that is not present in the platinum dimer salt. The nonintercalated complex is nonemissive in room-temperature fluid solution, but gives rise to intense blue-green emission in a 4:1 ethanol/methanol 77 K frozen glassy solution. Powders and colloidal suspensions of [{Pt(dmbpy)(μ-pz)}(2)](2+)-exchanged ZrP materials exhibit intense emissions at room-temperature.     

Partial specific adsorption of organic molecules in binary mixtures of adsorbents: 2,2'-bipyridine on kaolinite and hematite and 1,10-phenanthroline on montmorillonite and hydroxy-Al montmorillonite

The adsorption of 2,2'-bipyridyl in binary mixtures of sodium kaolinite and hematite at pH 6.6 and of 1,10-phenanthroline in binary mixtures of sodium montmorillonite and hydroxy-Al montmorillonite at pH 7.5 was studied as a function of the equilibrium concentration and composition of the mixture. A model is presented for determining the partial specific adsorption of two adsorbents by each component of the mixture, based on the graphic method for determining partial quantities. The partial specific adsorption values obtained for binary mixtures of Na-kaolinite with hematite and Na-montmorillonite with hydroxy-Al montmorillonite are strongly influenced by the concentration of adsorbates and adsorbents in the mixtures.     

Rapid mutation detection in complex genes by heteroduplex analysis with capillary array electrophoresis

Mutational analysis of large multiexon genes without prevalent mutations is a laborious undertaking that requires the use of a high-throughput scanning technique. The Human Genome Project has enabled the development of powerful techniques for mutation detection in large multiexon genes. We have transferred heteroduplex analysis (HA) by conformation-sensitive gel electrophoresis of the two major breast cancer (BC) predisposing genes, BRCA1 and BRCA2, to a multicapillary DNA sequencer in order to increase the throughput of this technique. This new method that we have called heteroduplex analysis by capillary array electrophoresis (HA-CAE) is based on the use of multiplex-polymerase chain reaction (PCR), different fluorescent labels and HA in a 16-capillary DNA sequencer. To date, a total of 114 different DNA sequence variants (19 insertions/deletions and 95 single-nucleotide substitutions - SNS) of BRCA1 and BRCA2 from 431 unrelated BC families have been successfully detected by HA-CAE. In addition, we have optimized the multiplex-PCR conditions for the colorectal cancer genes MLH1 and MSH2 in order to analyze them by HA-CAE. Both genes have been amplified in 13 multiplex groups, which contain the 35 exons, and their corresponding flanking intronic sequences. MLH1 and MSH2 have been analyzed in nine hereditary nonpolyposis colorectal cancer patients, and we have found six different DNA changes: one complex deletion/insertion mutation in MLH1 exon 19 and another five SNS. Only the complex mutation and one SNS may be classified as cancer-prone mutations. Our experience has revealed that HA-CAE is a simple, fast, reproducible and sensitive method to scan the sequences of complex genes.     

Room-temperature emission from platinum(II) complexes intercalated into zirconium phosphate-layered materials

The direct ion exchange of chloro(2,6-bis(N-methylbenzimidazol-2-yl)pyridine)platinum(II) ([Pt(Me(2)bzimpy)Cl]+) and chloro(2,2':6',2' '-terpyridine)platinum(II) ([Pt(tpy)Cl]+) complexes within a zirconium phosphate (ZrP) framework has been accomplished. The physical and spectroscopic properties of [Pt(Me(2)bzimpy)Cl]+ and [Pt(tpy)Cl]+ intercalated in ZrP were investigated by X-ray powder diffraction and X-ray photoelectron, infrared, absorption, and luminescence spectroscopies. In contrast to unintercalated complexes in fluid solution, which do not emit at room temperature, both intercalated materials in the solid state and in colloidal suspensions exhibit intense emissions at room temperature. A [Pt(Me(2)bzimpy)Cl]+-exchanged ZrP colloidal methanol suspension gives rise to an emission at 612 nm that originates from a lowest (3)MMLCT[dsigma*(Pt) --> pi*(tpy)] state (MMLCT = metal-metal-to-ligand charge transfer) characteristic of strong Pt...Pt interactions. A [Pt(tpy)Cl]+-exchanged ZrP colloidal aqueous suspension exhibits a strong emission band at 600 nm. The accumulated data demonstrate that at high concentrations, [Pt(Me(2)bzimpy)Cl]+ and [Pt(tpy)Cl]+ ions can serve as luminescent pillars inside the ZrP framework.     

Apparent and partial specific adsorption of 1,10-phenanthroline on mixtures of Ca-montmorillonite, activated carbon, and silica gel

The process of 1,10-phenanthroline adsorption at pH 5 on Ca-montmorillonite, activated carbon, and silica gel mixtures was studied as a function of the equilibrium concentration and the composition of the mixture. A model is presented for determining adsorption of the main component (the variable in the system) of the mixture, based on the thermodynamic concept of apparent and partial quantities, in combination with an equation representing total adsorption of the other two adsorbents as a function of the weight fraction of one of them and introducing the concept of mean total adsorption. The partial specific adsorption of orthophenanthroline (OP) on Ca-montmorillonite is strongly influenced by the presence of activated carbon and silica gel. Owing to a phenomenon of cationic exchange, adsorption on the clay is higher at low proportions in the mixture, but the strong effect of carbon and silica gel becomes apparent at increasing amounts of clay in the mixture. The partial specific adsorption of orthophenanthroline on activated carbon and silica gel was determined using a total adsorption equation for the two adsorbents as a function of the weight fraction of one of them and shows behavior inverse to that of adsorption on clay.     

Bi2n+4MonO6(n+1) with n=3, 4, 5, 6: A new series of low-temperature stable phases in the mBi2O3 - MoO3 system (1.0<m<1.7): Structural relationships and conductor properties

Four low-temperature phases with compositions Bi₁₀Mo₃O₂₄, Bi₆Mo₂O₁₅, Bi₁₄Mo₅O₃₆ and Bi₈Mo₃O₂₁ have been prepared by the n-butylamine wet synthesis method. They have been characterized by powder X-ray diffraction and transmission electron microscopy, mainly by selected area electron diffraction. The four phases present a close structural relationship and a common basic fluorite-type structure and are members of a homologous series of phases with general formula Bi_2n+4Mo_nO_6(n+1), being n=3, 4, 5 and 6, respectively. The matrices relating their superstructures and the basic fluorite type unit cell are given, as well as a general one for the whole series. The conductor behavior of these phases is characterized by impedance spectroscopy being all these materials very good ionic conductors.