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Complete statistical randomization of the direction of propagation of light trapped in semiconductor films can result in a large absorption enhancement. We have employed a calorimetric technique, photothermal deflection spectroscopy, to monitor the absorption of alpha-SiH(x) films textured by the natural lithography process. The observed enhancement factors, as high as 11.5, are consistent with full internal phase-space randomization of the incoming light.
Pyometra is a life-threatening uterine condition in unspayed bitches, typically developing during the luteal phase and characterized by purulent uterine discharge and systemic inflammatory manifestations. This case study reports the diagnostic, therapeutic, and monitoring approach in a 6.3-year-old female Chow Chow presented with lethargy, inappetence, and purulent vaginal discharge. Comprehensive evaluation included clinical, hematological, biochemical, imaging, and cytological investigations. Marked leukocytosis, neutrophilia, anemia, and thrombocytopenia were noted, along with significant biochemical alterations indicating systemic involvement. Diagnosis was confirmed via abdominal ultrasound and laboratory profiles. Complications during hospitalization included epistaxis, progressive anemia, and secondary infections with Mycoplasma haemocanis and Candida parapsilosis, necessitating blood transfusions and antifungal therapy. Hematological biomarkers were dynamically monitored throughout treatment and proved valuable in evaluating disease progression, therapeutic efficacy, and clinical prognosis. The case highlights the importance of serial hematological and biochemical assessments in managing canine pyometra and its complications.
Abstract The design, synthesis, and properties of supermolecules consisting of well defined assemblies of linear and globular macromolecules is studied. Therefore, several families of hybrid block polymers based on polyether dendrimers linked to well‐defined blocks of polyethylene oxide, polyethylene glycol, polyester, or polystyrene have been prepared. The unique topological macromolecules that result from the assembly of such components having different shapes and internal densities can assemble in highly stable supramolecular micelles whose characteristics vary as a function of the medium. The hybrid macromolecules are usually prepared by the nucleophilic displacement of a reactive functionality located at the focal point of a convergent polyether dendrimer, with a nucleophilic anion located at one or both chain ends of a linear polymer. Alternately, the focal point of the dendrimer may be used to attach a polymerizable vinyl group affording a dendritic macromonomer that may be used to create variety of copolymers. Finally, the focal point of the convergent dendrimer may serve as an initiator in the polymerization of a linear chain thereby affording the hybrid linear‐dendritic entity. In the latter case the unique microenvironment provided by the dendrimer is useful in the prevention of undesirable side‐reactions during growth of the linear block. This demonstrates that the differences between the globular and linear fragments of these unique molecules can be used to design nanoscale reactors that perform functions not normally achieved with small molecules. The very unusual solution properties of the dendritic‐linear supermolecules are a direct result of the forced combination of their dissimilar building blocks.
A ThO.sub.2 catalyst having a high surface area of about 80-125 m.sup.2 /g is synthesized. The compound is synthesized by simultaneously mixing an aqueous solution of ThNO.sub.3 (NO.sub.3).sub.4.4H.sub.2 O with an aqueous solution of Na.sub.2 CO.sub.3.H.sub.2 O, to produce a solution and solid ThOCO.sub.3. The solid ThOCO.sub.3 is separated from the solution, and then calcined at a temperature of about 225.degree.-300.degree. C. for about 40-55 hours to produce ThO.sub.2. The ThO.sub.2 catalyst produced includes Na present as a substitutional cation in an amount equal to about 5-10 atom percent.
Using newly assembled data on foreign exchange market intervention, we construct a daily index of exchange market pressure during the 1992-3 crisis in the European Monetary System, allowing us to pinpoint when and where the crisis was most severe. Our analysis focuses on a neglected factor in the crisis: the role of the weak dollar in intra-EMS tensions. We provide new evidence of the contribution of a falling dollar-Deutschmark exchange rate to pressure on EMS currencies.
A DNA cassette system has been developed to allow for the convenient introduction of synthetic DNA oligonucleotides between the transcription and translation start sites of a gene in order to examine the effect of 5' hairpin structure and strength on mRNA stabilization. Rationally designed synthetic DNA cassettes were introduced into the 5' untranslated region of a modified lacZ gene to form hairpins at the 5' end of the mRNA. These DNA inserts influenced mRNA half-lives over an order-of-magnitude range, with some groups of predicted structures having half-lives that showed a strong correlation with hairpin strength while half-lives for another group of predicted structures exhibited little or no dependence on this property. These results indicate the importance of 5' hairpin structure and strength in determining stabilization of Escherichia coli mRNA. This synthetic library, as well others generated using the DNA cassette system described here, should prove useful in understanding the mechanisms of mRNA stabilization and in designing structures for recombinant gene expression control.
[H]istory … suggests taking more seriously concerns about inequality and, specifically, the resentment and alienation of once-privileged groups who feel left behind.
To obviate the destructive interaction of highly reactive metallocene catalysts with classical silica-based supports while retaining the advantage of supported catalysts, a noninteracting polystyrene support was developed. Supported catalysts for the polymerization of α-olefins are prepared by treating lightly cross-linked, chloromethylated polystyrene beads consecutively with a secondary amine, an ammonium salt of a weakly coordinating anion, and a neutral dialkylmetallocene. Catalytic sites are distributed homogeneously throughout the support particle, and the polymerization occurs within the bead, in contrast to traditional surface-supported metallocene catalysts. The copolymerization of ethylene and 1-hexene at 40°C affords discrete spherical polyolefin beads with a size (0.3 to 1.4 millimeters) that varies according to the polymerization time.
