Rheology/morphology interactions in polypropylene/polyamide-6 nanocomposites

Polypropylene/polyamide-6 (PP/PA-6) blends and their nanocomposites with unmodified and organically treated layered silicates (montmorillonite) were prepared in a melt compounding process to explore their mechanical performance. The rheology and morphology of these materials was studied. It could be shown that in all cases the inorganic filler enriched in the PA phase, resulting in a phase coarsening of the PP/PA nanocomposite as compared to the non-filled PP/PA blend. The mechanical properties of these nanoblends are consequently only slightly better than the pure polymers with respect to the modulus, while the impact level is below the pure polymers, reflecting the heterogeneity of the nanoblend.     

Interpretation of seasonal variation of metals and abiotic properties in a tropical lake using multivariate analysis and MINTEQA2 program.

The hydrological cycle of Lake Ipê and the principal parameters that could affect its abiotic parameters and its metal (Fe, Mn, and Cd) concentrations were investigated. A detailed study of seasonal variations using Principal Components Analysis (PCA) for the most relevant metals (Fe, Mn and Cd) was performed, assisted by the MINTEQA2 geochemical equilibrium program using 15 water abiotic parameters. The abiotic variables and metals in the lake were governed by the hydrological regimen of the Parana River and by the occurrence of occasional flood pulses and rainfall. The occurrence of cadmium is a concern; its presence could be due to industrial or agricultural activities or even to a natural geochemical process.     

New flavan and unusual chalcone glycosides from Drypetes parvifolia

Two new compounds 7-hydroxy-5-O-（β-D-glucopyranoside） flavan （1） and （Z）-4＇,6＇-dihydroxy-2＇-O-（β-D-glucopyranoside） chalcone （2）, along with eight known compounds, were isolated from the stem bark of Drypetes parvifolia （Euphorbiaceae）. Their structures were established on the basis of spectroscopic analysis and chemical evidence.     

Phase Transition of a Dicyanamide with Rutile‐like Structure: Syntheses and Crystal Structures of α‐ and β‐Cd[N(CN)2]2

Cadmium dicyanamide Cd[N(CN)₂]₂ was synthesized through aqueous ion exchange at room temperature. A reversible phase transition was detected by in situ X‐ray powder diffractometry above 55 °C. The crystal structures of both phases were determined by X‐ray powder diffraction (β‐Cd[N(CN)₂]₂: T = 22 °C, a = 621.60(3), b = 748.76(4), c = 770.21(5) pm, β = 91.784(3)°, P2₁/n (no. 14), Z = 2, wR_p = 0.063, R_p = 0.050, R_F = 0.059; α‐Cd[N(CN)₂]₂: T = 150 °C, a = 624.62(5), b = 752.92(6), c = 768.30(7) pm, Pnnm (no. 58), Z = 2, wR_p = 0.083, R_p = 0.064, R_F = 0.087). Both polymorphs consist of Cd²⁺ and bent planar [N(CN)₂]^— ions. α‐Cd[N(CN)₂]₂ crystallizes analogously to rutile and is isotypic with M^II[N(CN)₂]₂(M = Mg, Cr, Mn, Co, Ni, Cu). The monoclinic low‐temperature polymorph β‐Cd[N(CN)₂]₂ is closely related to that of the orthorhombic high‐temperature polymorph α‐Cd[N(CN)₂]₂ by a translationengleiche transition of index 2.     

Kakao

Analytical and Bioanalytical Chemistry -     

High Temporal Resolution Monitoring of Fermentations Using an On‐Line Amperometric Flow‐Through Microdetector

An on‐line microdetector containing amperometric biosensors was used for high temporal resolution (t_90%≈120 s) monitoring of glucose and ethanol concentrations during small scale fermentations. The ability of the microdetector to report on the effect of different experimental conditions was tested in fermentation processes carried out at 30 and at 37 °C. An increased ethanol production rate accompanied by an increased glucose consumption rate in the fermentation carried out at 37 °C was promptly revealed. Therefore, the microdetector proved to be an especially useful tool to monitor fermentations where the investigated processes are too fast to be followed by classical analytical approaches.     

Synthesis and properties of fluorene‐based polyheteroarylenes for photovoltaic devices

Novel copolymers consisting of the alternating push–pull comonomers fluorene and thieno[3,4‐b]pyrazine/quinoxaline were synthesized by a palladium‐catalyzed Suzuki cross‐coupling reaction in 60–80% yields. The structure of the deeply colored copolymers was confirmed with ¹H and ¹³C NMR. All the new materials were characterized with spectroscopic and electrochemical methods. Bulk heterojunction organic solar cells based on some of the novel polymers in combination with the well‐known fullerene acceptor [6,6]‐phenyl C₆₁–butyric acid methyl ester were fabricated, and their photovoltaic parameters were measured. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6952–6961, 2006     

Determining ProGRP and isoforms in lung and thyroid cancer patient samples: comparing an MS method with a routine clinical immunoassay

This paper compares two methods to determine the tumor marker progastrin-releasing peptide (ProGRP): as routine assay, the automated time-resolved immunofluorometric assay (TR-IFMA), which allows total ProGRP determination; and the immunocapture liquid chromatography selected reaction monitoring mass spectrometry (LC–SRM-MS) method, which additionally allows isoform differentiation. The investigation included 60 serum samples from patients suffering from various cancer diseases which may cause elevated ProGRP levels (small cell lung carcinoma; SCLC, non-small cell lung carcinoma; NCLC; and medullary thyroid cancer; MTC, as well as some with unspecific diagnosis). The two methods showed good correlation (R ²?=?0.887). However, the MS method determines the total ProGRP concentration systematically approximately 30 % lower than the TR-IFMA, implying that the absolute values generated by the methods are not interchangeable. The MS method gives additional information about isoform levels in the samples, providing novel insight into isoform expression on the protein level.