Synthesis of polyethers of hexafluorobenzene and hexafluoropentanediol

Two new polyethers, poly /hexafluoropentamethylene tetrafluoro-p-phenylene ether/ and a completely hydroxyl-terminated polyether, is prepared by reactions of hexafluorobenzene with hexafluoropentanediol. The polyethers can be prepared as low molecular weight oils, as intermediate molecular weight waxes, or as high molecular weight elastomers

Targeted therapy for breast cancer prevention.

With a better understanding of the etiology of breast cancer, molecularly targeted drugs have been developed and are being testing for the treatment and prevention of breast cancer. Targeted drugs that inhibit the estrogen receptor (ER) or estrogen-activated pathways include the selective ER modulators (tamoxifen, raloxifene, and lasofoxifene) and aromatase inhibitors (AIs) (anastrozole, letrozole, and exemestane) have been tested in preclinical and clinical studies. Tamoxifen and raloxifene have been shown to reduce the risk of breast cancer and promising results of AIs in breast cancer trials, suggest that AIs might be even more effective in the prevention of ER-positive breast cancer. However, these agents only prevent ER-positive breast cancer. Therefore, current research is focused on identifying preventive therapies for other forms of breast cancer such as human epidermal growth factor receptor 2 (HER2)-positive and triple-negative breast cancer (TNBC, breast cancer that does express ER, progesterone receptor, or HER2). HER2-positive breast cancers are currently treated with anti-HER2 therapies including trastuzumab and lapatinib, and preclinical and clinical studies are now being conducted to test these drugs for the prevention of HER2-positive breast cancers. Several promising agents currently being tested in cancer prevention trials for the prevention of TNBC include poly(ADP-ribose) polymerase inhibitors, vitamin D, and rexinoids, both of which activate nuclear hormone receptors (the vitamin D and retinoid X receptors). This review discusses currently used breast cancer preventive drugs, and describes the progress of research striving to identify and develop more effective preventive agents for all forms of breast cancer

Geluidmonitor 2014

Het RIVM heeft in 2013 geluidmetingen verricht op 23 locaties langs rijkswegen en op 26 locaties langs spoorwegen. Langs rijkswegen bleek het gemiddelde geluidniveau substantieel (2,4 decibel) hoger te liggen dan de berekende waarde. Langs het spoor was er gemiddeld geen significant verschil (0,5 dB). Afhankelijk van de meetlocatie kunnen de verschillen groter of kleiner zijn. De verschillen langs rijkswegen worden veroorzaakt door het feit dat de wettelijk voorgeschreven rekenmethode uitgaat van stille banden op een droog wegdek bij een standaardtemperatuur van 20 graden Celsius. De omstandigheden zijn vaak ongunstiger. Daarnaast draagt de variatie in akoestische kwaliteit van het wegdek bij aan de verschillen. Het meetprogramma vloeit voort uit een motie van de Tweede Kamer naar aanleiding van geluidwetgeving uit 2012. De wet stelt grenswaarden aan het geluid langs rijkswegen en spoorwegen. De wegen spoorbeheerder (Rijkswaterstaat en ProRail) dienen met een jaarlijkse berekening aan te tonen hieraan te voldoen. Onderdeel van de wet is ook een validatie van de rekenuitkomsten met metingen. Het RIVM verricht hiertoe jaarlijks geluidmetingen en vergelijkt die met de berekende geluidproductie die de weg- en spoorbeheerder rapporteren. Dit rapport gaat in op de verschillen tussen reken en meetresultaten in 2013. Het rapport geeft ook de meetresultaten uit 2014 langs rijkswegen en spoorwegen op 92 meetlocaties. Deze zullen worden vergeleken met de rekenresultaten die door de weg- en spoorbeheerder gepubliceerd worden in september 2015. Hierover zal het RIVM in 2016 rapporteren. Als blijkt dat de verschillen tussen de meet- en rekenwaarden structureel zijn, is nader onderzoek nodig naar de gezondheidskundige relevantie voor de Nederlandse bevolking en naar de vraag of aanpassingen van de rekenmethode nodig zijn.In 2013 RIVM has conducted noise measurements at 23 locations along motorways and at 26 locations along railways. Along motorways, the average measured noise level was substantially (2,4 dB) higher than the calculated value. Along the track, on average no significant difference was found (0,5 dB). Depending on the measurement location, larger or smaller differences can be found. The differences along motorways are partly due to the calculation method, which is based on low-noise tires on dry surfaces at a standard temperature of 20 degrees Celsius. The average conditions are less favorable. Also the variation in acoustic quality of the road surface contributes to the differences. For rail, no clear causes of differences are yet to be declared. The measurement program stems from a motion of the House in response to noise legislation (Swung) proposed and accepted in 2012. This Act sets limits on noise along motorways and railways. The administrators, Rijkswaterstaat and ProRail, annually demonstrate by a statutory calculation to fulfill this requirement. The legislation also requires validation of the calculation results by measurements. To this aim RIVM annually conducts measurements and compares the results with the calculated noise production as reported by the road- and railway administrator. This report discusses the differences between calculation and measurement results in 2013. It also contains the measurement results from 2014, along motorways and railroads on a sample of 92 measuring sites. These results will be compared with the calculation results, after they are published in September 2015 by the road- and railway administrator. If it appears that the differences between measurement and calculation are structural, further research is needed into the health implications for the Dutch population and whether adjustments to the calculation methods are needed.Ministerie van I&

The Potential of Restarts for ProbSAT

This work analyses the potential of restarts for probSAT, a quite successful algorithm for k-SAT, by estimating its runtime distributions on random 3-SAT instances that are close to the phase transition. We estimate an optimal restart time from empirical data, reaching a potential speedup factor of 1.39. Calculating restart times from fitted probability distributions reduces this factor to a maximum of 1.30. A spin-off result is that the Weibull distribution approximates the runtime distribution for over 93% of the used instances well. A machine learning pipeline is presented to compute a restart time for a fixed-cutoff strategy to exploit this potential. The main components of the pipeline are a random forest for determining the distribution type and a neural network for the distribution's parameters. ProbSAT performs statistically significantly better than Luby's restart strategy and the policy without restarts when using the presented approach. The structure is particularly advantageous on hard problems.Comment: Eurocast 201

Trapping reactions with subdiffusive traps and particles characterized by different anomalous diffusion exponents

A number of results for reactions involving subdiffusive species all with the same anomalous exponent gamma have recently appeared in the literature and can often be understood in terms of a subordination principle whereby time t in ordinary diffusion is replaced by t^gamma. However, very few results are known for reactions involving different species characterized by different anomalous diffusion exponents. Here we study the reaction dynamics of a (sub)diffusive particle surrounded by a sea of (sub)diffusive traps in one dimension. We find rigorous results for the asymptotic survival probability of the particle in most cases, with the exception of the case of a particle that diffuses normally while the anomalous diffusion exponent of the traps is smaller than 2/3.Comment: To appear in Phys. Rev.

Binary data corruption due to a Brownian agent

We introduce a model of binary data corruption induced by a Brownian agent (active random walker) on a d-dimensional lattice. A continuum formulation allows the exact calculation of several quantities related to the density of corrupted bits \rho; for example the mean of \rho, and the density-density correlation function. Excellent agreement is found with the results from numerical simulations. We also calculate the probability distribution of \rho in d=1, which is found to be log-normal, indicating that the system is governed by extreme fluctuations.Comment: 39 pages, 10 figures, RevTe