Die Schmelz- und Sättigungskurven der binären Systeme: Substituierte Benzoesäuren und Wasser

Ohne Zusammenfassung     

Calculation and Measurement of Terahertz Active Normal Modes in Crystalline PETN

The terahertz frequency spectrum of pentaerythritol tetranitrate (PETN) is calculated using Discover 1 with the COMPASS 2 force field, CASTEP^[3] and PWscf. 4 The calculations are compared to each other and to terahertz spectra (0.3–3 THz) of crystalline PETN recorded at 4 K. A number of analysis methods are used to characterise the calculated normal modes.     

Terahertz imaging through self-mixing in a quantum cascade laser

We demonstrate terahertz (THz) frequency imaging using a single quantum cascade laser (QCL) device for both generation and sensing of THz radiation. Detection is achieved by utilizing the effect of self-mixing in the THz QCL, and, specifically, by monitoring perturbations to the voltage across the QCL, induced by light reflected from an external object back into the laser cavity. Self-mixing imaging offers high sensitivity, a potentially fast response, and a simple, compact optical design, and we show that it can be used to obtain high-resolution reflection images of exemplar structures.     

Facile synthesis of core‐surface crosslinked nanoparticles by interblock RAFT polymerization

A new, efficient method for synthesizing stable nanoparticles with poly(ethylene oxide) (PEO) functionalities on the core surface, in which the micellization and crosslinking reactions occur in one pot, has been developed. First, amphiphilic PEO‐b‐PS copolymers were synthesized by reversible addition fragmentation chain transfer (RAFT) radical polymerization of styrene using (PEO)‐based trithiocarbonate as a macro‐RAFT agent. The low molecular weight PEO‐b‐PS copolymer was dissolved in isopropyl alcohol where the block copolymer self‐assembled as core‐shell micelles, and then the core‐shell interface crosslink was performed using divinylbenzene as a crosslinking agent and 2,2′‐azobisisobutyronitrile as an initiator. The design of the amphiphilic RAFT agent is critical for the successful preparation of core‐shell interface crosslinked micellar nanoparticles, because of RAFT functional groups interconnect PEO and polystyrene blocks. The PEO functionality of the nanoparticles surface was confirmed by ¹H NMR and FTIR. The size and morphology of the nanoparticles was confirmed by scanning electron microscopy, transmission electron microscopy, and dynamic laser light scattering analysis. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Effect of artificial mucus properties on the characteristics of airborne bioaerosol droplets generated during simulated coughing

The effect of viscoelastic properties and surface tension of artificial mucus simulant samples on the size distribution and volume concentration of bioaerosol droplets generated during simulated coughing was investigated through in vitro experiments. The mucus simulant samples had viscoelastic properties in a similar range as those of real human airway mucus. The mucus simulant gels were prepared by mixing various proportions of 0.5–1.7% locust bean gum solution and 0.1 M sodium tetraborate (XLB) solution. Surface tension of one set of samples was varied by adding different amounts of SDS (sodium dodecyl sulfate) surfactant while the measurement of surface tension was performed using ADSA (axisymmetric drop shape analysis) method. The viscoelastic properties of the samples were measured using a Bohlin Gemini 200 HR (Malvern, UK) nano-rheometer with peltier plate assembly. An artificial cough machine was used to simulate human cough, generating aerosol droplets in a model trachea attached to the front of the cough machine. The size distribution and volume concentration of the droplets generated through simulated cough were measured using a laser diffraction particle sizer (SprayTec, Malvern, USA). The surface tension was found to have negligible effect on the characteristic of generated droplets within the range of this investigation. The experimental results showed a decrease in particle size as the samples changed from a viscous fluid type to a viscoelastic to an elastic solid type sample. The volume concentration also changed significantly as the viscoelasticity of the samples was varied.     

Weighted exponential regression for characterizing radionuclide concentrations in soil depth profiles

Radium concentration was determined in 23 types of bottled mineral waters, commercially available in Romania. Using the Lucas cells with the device Luk 3A, the radium concentration was determined directly, after the radon balanced with radium. From these measurements, the corresponding annual effective ingestion dose was determined.     

Some synthetic approaches to ropinirole (sk&f 101468-a): A potent dopamine receptor agonist

Three new routes to ropinirole (SK&F 101468-A, 1 ) are described each involving the preparation of 3-chlorooxindole intermediates of type 3 from β-nitrostyrenes as the pivotal step. The superiority of sulphonate esters 17a-c as direct precursors to 1 over the bromide 11 is also described.     

Familial aggregation of early-onset myocardial infarction

Although ischemic heart disease tends to cluster in families, previous studies have reported a modest (2-fold increased risk) to strong (10-fold increased risk) contribution of family history to the explanation of disease occurrence. The authors assessed the familial aggregation of early-onset myocardial infarction in 11,307 adults aged <65 years who participated in the Third National Health and Nutrition Examination Survey. Logistic regression was used to obtain odds ratios (ORs) and 95% confidence intervals (CIs). A parental history was more common in those with (n = 237) than in those without (n = 11,070) a myocardial infarction (19.8 vs. 7.9%, p < or = 0.01). Adults with a parental history were also more likely to have multiple risk factors for cardiovascular disease (OR for four or five risk factors compared with none: 2.9, 95% CI: 1.4, 6.3). After multivariate adjustment, the likelihood of myocardial infarction was more than three times greater among adults with a parental history than among those without (95% CI: 1.7, 6.7). A maternal history of myocardial infarction was strongly associated (OR = 6.1, 95% CI: 2.1, 17.4) with an increased likelihood of myocardial infarction, and a paternal history was associated with a 3-fold (95% CI: 1.5, 6.3) increased likelihood of myocardial infarction after adjustment for cardiovascular disease risk factors. These results suggest a familial aggregation of early-onset myocardial infarction and show that family history is strongly associated with cardiovascular disease risk factors.