A study of the ethical duty of physicians to disclose errors

A quantitative immunocytochemical procedure was used for evaluation of the blood-brain barrier (BBB) to endogenous albumin in plaque-forming (PF) and non-plaque-forming (NPF) groups of scrapie-infected mice at the clinical stage of disease. Ultrathin sections of brain samples (cerebral cortex, hippocampus and cerebellum) embedded in resin (Lowicryl K4M) were exposed to anti-mouse albumin antiserum followed by protein A-gold. Using morphometry, the density of immunosignals (gold particles per microns2) was recorded over four compartments: vascular lumen, endothelium, subendothelial space, and brain parenchyma (neuropil). Morphometric and statistical analyses did not reveal significant differences in the barrier function of the microvasculature of the cerebral cortex and hippocampus in either group of mice, although a slight increase in the number of leaking vessels in the PF group was noted. In contrast, in the cerebellum, the permeability of the microvessels to albumin was significantly higher in the PF than in the NPF mouse group, and this was paralleled by the infiltration of the walls of numerous vascular profiles with amyloid deposits (amyloid angiopathy). These data also indicate the existence of distinct regional differences in BBB function in the brain of scrapie-infected mice. The vascular amyloid deposits and the amyloid plaques present in the cerebral cortex of PF mice were labeled with numerous immunosignals suggesting the affinity of extravasated albumin to these deposits. In conclusion, no convincing evidence was obtained indicating that impairment of the BBB, manifested by increased permeability of vascular segments, is directly related to the deposition of amyloid in the vascular wall and in plaques. Segmental impairment of the barrier function seems to be rather the result of disturbed structural integrity of the components of the vascular wall.     

Measuring number‐concentrations of nanoparticles and viruses in liquids on‐line

BACKGROUND: The surge of studies on artificial and natural nanoparticles has revealed a new world for engineering and life sciences, but in most instances, the small scale has made their number‐concentration determination in liquids a challenging problem. Former success has mostly been limited to special particles measured by indirect techniques. A new approach is required for this determination to facilitate the production and application of nanoparticles in different systems. RESULT: Here, an approach is described using a nanoparticle tracking system based on Brownian motion, which can be used to determine the number‐concentration of nanoparticles, including viruses, in liquids on‐line. Extensive analysis showed the influence of suspension concentration and particle size on the accuracy of measurements. Natural nanoparticles of Adenovirus and several types of artificial nanoparticles, including precision nanobeads, uniform inorganic silica microspheres, monodisperse gold metal colloids and aggregated Aerosil nanoparticles, were measured and compared by counting the monitored particle number obtained using light scattered from individual particles, from which the particle number‐concentration, the product yield and the aggregation could be evaluated. CONCLUSION: This approach was compared with the mathematical calculation method and the emission spectrophotometry technique used for practical applications. The results showed this new approach had improved accuracy for determination of the particle number‐concentration. Copyright © 2010 Society of Chemical Industry     

Structures and pesticidal activities of derivatives of dinitrophenols. XI. Effects of substitution of dinitrophenols with C3 to C13 alpha-branched alkyl groups and of esterification on the eradication of cucumber mildew

The eradication of cucumber mildew caused by Sphaerotheca fuliginea (Schlecht. ex Fr.) Poll. with 2-(C₄ to C₁₃ α-branched alkyl)-4,6-dinitrophenols and 4-(C₄ to C₁₃ α-branched alkyl)-2,6-dinitrophenols was examined. 2-(C₈ to C₁₃ α-Branched alkyl)-4,6-dinitrophenols were highly active, but O-methylation produced compounds with no activity. 4-(C₇ to C₁₀ and several C₁₁ to C₁₃ α-branched alkyl)-2,6-dinitro-phenols gave a significant degree of eradication. 2-(C₆ to C₁₃ α-Branched alkyl)-4,6-dinitrophenols were significantly more active than their 4-alkyl-2,6-dinitrophenol analogues. Esterification of C₄ to C₇ α-branched alkyl dinitrophenols to methyl- or ethyl- carbonates or crotonates gave compounds with enhanced activity. Generally, the methyl- or ethyl- carbonates or 2-C₈-alkyl-4,6-dinitrophenols were as active as the parent phenols, but the higher alkyl carbonates or crotonates had lower activity. Esterification of 2-(C₉ to C₁₃ α-branched alkyl)-4,6-dinitrophenols to ethyl carbonates and crotonates gave compounds with reduced activity.     

The use of functionalized polymers as photosensitizers in an energy storage reaction

Insoluble polymer bound photosensitizers, useful for the conversion of norbornadiene (1) to quadricyclene (2), have been synthesized. An acetophenone analogue was produced by Friedel-Crafts acylation of polystyrene resin while treatment of chloromethylated resin with salicyladehyde and triethylamine produced an anlogue of benzyloxybenzaldehyde. Reaction of lithio---polystyrene resin with methyl 4-(N,N-dimethylamino)benzoate gave a ketone equivalent to 4-(N,N-dimethylamino)benzophenone (3). Quantum yields for the conversion of 1 and 2 using the polymer bound sensitizers were generally comparable to, but slightly lower than, the analogous compound in homogeneous solution. The quantum yield of polymer bound 3 was less solvent dependent than that of the homogeneous counterpart. The advantages of isolating the photosensitizer to the photochemical reactor stage of a photochemical solar energy storage device are discussed. Efficient sensitization by polymer bound photosensitizers demonstrates the feasibility of this approach.     

Structures and pesticidal activities of derivatives of dinitrophenols. IX. Effects of substitution of dinitrophenols with C4 to C13 alpha-branched alkyl groups and of esterification on the eradication of apple mildew

The eradication of apple mildew caused by Podosphaera leucotricha (Ell. and Everh.) Salm. with 2-(C₄ to C₁₃ α-branched alkyl)-4,6-dinitrophenols and 4-(C₄ to C₁₃ α-branched alkyl)-2,6-dinitrophenols was examined. 4-(1-Ethylbutyl)- and most 4-(C₇ to C₁₂ α-branched alkyl)-2,6-dinitrophenols were significantly more active than their 2-alkyl-4,6-dinitrophenol analogues. Compounds containing 4-C₁₃ alkyls did not show significant activity. Activity generally increased as the α-alkyl branch lengthened. Methyl carbonates did not show lower activity than the parent phenols, but esterification of 4-(C₁₂ or C₁₃ α-branched alkyl)-2,6-dinitrophenols to ethyl carbonates or crotonates gave compounds with reduced activity. Methyl-, ethyl- or isopropyl-carbonates and crotonates of 4-(1-ethylhexyl)-2,6-dinitrophenol had much higher activity than the corresponding esters of the 4-(1-methylheptyl) isomer or of 2-(1-ethyl-hexyl)-4,6-dinitrophenol. Compounds containing long ester chains (C₇ or C₈) had less activity than 4-(1-ethylhexyl)-2,6-dinitrophenol. O-Methylation produced compounds with less activity than the parent 4-(1-ethylhexyl)- and 4-(1-propyl-pentyl)-2,6-dinitrophenols.     

A novel trench clustered insulated gate bipolar transistor (TCIGBT)

A new trench clustered insulated gate bipolar transistor (TCIGBT) is reported. In this device, a multitude of UMOS cathode cells is enclosed within a common n-well and p-well. The TCIGBT provides a unique "self-clamping" feature to protect the trenches from high electric fields. The simulation results based on 1.2 kV nonpunchthrough technology indicate an improvement of 25% in on state and 28% in the turn-off losses in comparison to the state-of-the-art trench IGBT. The saturation current levels of the TCIGBT, which can be designed independent of the forward drop, are also lower.