all-S,S-dioxygenated star oligothiophenes

Star-shaped oligothiophenes are promising materials for applications in the organic electronics field. For the first time, a range of star-oligothiophenes was oxidized to the corresponding all-S,S-dioxides by using the HOF·CH(3)CN complex. These materials exhibit considerable thermal stability and red-shift absorptions in the UV/vis relative to the parent compounds.     

Synthesis of difluoroaryldioxoles using BrF3

A novel synthesis of different aromatic and heteroaromatic difluorodioxole derivatives has been developed. The starting materials were catechols, which, after treatment with thiophosgene, formed at 0 °C the respective thiodioxoles. The latter were reacted for a short time with commercially available bromine trifluoride, producing potentially biologically important difluoroaryldioxoles in moderate to high yields.     

Analyzing the calcination of sulfur-rich calcareous oil shales using FT-IR spectroscopy and applying curve-fitting technique

The thermal processes during progressive calcination of sulfur-rich calcareous oil shales were analyzed using FT-IR spectroscopy and applying curve-fitting technique. The spectroscopic analysis is advantageous in the analysis of amorphous and short-range ordered thermal phases lacking of XRD peaks. The raw calcareous oil shales are composed of organic matter, kaolinite, smectite, calcite, and apatite (francolite). The principal thermal phases are metakaolinite, meta-smectite, free lime, anhydrite, gehlenite, and ellestadite. The thermal reactions observed with increase temperatures includes decomposition of organic matter followed by release of sulfur gas; dehydroxylation of kaolinite; and smectite at 500–600 °C; and thermal transformation to metakaolinite and meta-smectite; decarbonation of microcrystalline calcite to free lime at 600 °C; reaction of the sulfur gas with the free lime; formation of anhydrite at 600 °C; reaction of apatite and formation of ellestadite at 800 °C; reaction of the metakaolinite; the meta-smectite with the free lime; formation of gehlenite at 900 °C. Owingto the sulfatization process, a great part of the sulfur content of the raw oil shales is retained in the calcined ashes and the release of sulfur gas to the atmosphere decreases. Thus, the combustion of calcareous oil shales for energy source has less pollution effect than that of the clayey oil shales. FT-IR spectroscopy and spectral analysis seems to be useful methods for phase analysis of oil shales in combustion industry.     

The stability of the viscous shock profiles of the burgers’ equation with a fourth order viscosity

We establish the stability of the viscous shock profiles of the Burgers' equation with fourth order viscosity in a weighted Sobolev space. In the course of our investigation, we develop a new method for dealing with the continuous spectrum of certain types of ordinary and partial differential operators in Hilbert spaces. This method allows us to get results in spaces that are related to L² rather than forcing us to work in spaces related to L^∞.     

Reductions of Tensor Categories Modulo Primes

We study good (i.e., semisimple) reductions of semisimple rigid tensor categories modulo primes. A prime p is called good for a semisimple rigid tensor category 𝒞 if such a reduction exists (otherwise, it is called bad). It is clear that a good prime must be relatively prime to the Müger squared norm |V|² of any simple object V of 𝒞. We show, using the Ito–Michler theorem in finite group theory, that for group-theoretical fusion categories, the converse is true. While the converse is false for general fusion categories, we obtain results about good and bad primes for many known fusion categories (e.g., for Verlinde categories). We also state some questions and conjectures regarding good and bad primes.     

Novel magnetic Fe onion-like fullerene micrometer-sized particles of narrow size distribution

Magnetic polydivinylbenzene (PDVB)/magnetite micrometer-sized particles of narrow size distribution were prepared by entrapping Fe(CO)₅ within the pores of uniform porous PDVB particles, followed by the thermal decomposition of the encapsulated Fe(CO)₅ at 300 °C in a sealed cell under inert atmosphere. Magnetic Fe onion-like fullerene micrometer-sized particles of narrow size distribution have been prepared by the thermal decomposition of the PDVB/magnetite magnetic microspheres at 1100 °C under inert atmosphere. The graphitic coating protects the elemental iron particles from oxidation and thereby preserves their very high magnetic moment for at least a year. Characterization of these unique magnetic carbon graphitic particles was also performed.     

An asymptotically optimal online algorithm to minimize the total completion time on two multipurpose machines with unit processing times

In the majority of works on online scheduling on multipurpose machines the objective is to minimize the makespan. We, in contrast, consider the objective of minimizing the total completion time. For this purpose, we analyze an online-list scheduling problem of $n$ jobs with unit processing times on a set of two machines working in parallel. Each job belongs to one of two sets of job types. Jobs belonging to the first set can be processed on either of the two machines while jobs belonging to the second set can only be processed on the second machine. We present an online algorithm with a competitive ratio of ${\rho }_{LB}+O\left(\frac{1}{n}\right)$, where ${\rho }_{LB}$ is a lower bound on the competitive ratio of any online algorithm and is equal to $1+{\left(\frac{?\alpha +\sqrt{4{\alpha }^3?{\alpha }^2+2\alpha ?1}}{2{\alpha }^2+1}\right)}^2$ where $\alpha =\frac{1}{3}+\frac{1}{6}{(116?6\sqrt{78})}^{1/3}+\frac{{(58+3\sqrt{78})}^{1/3}}{3{\left(2\right)}^{2/3}}\approx 1.918$. This result implies that our online algorithm is asymptotically optimal.     

Comparison of different mathematical models of diffusion-weighted prostate MR imaging

Purpose

To evaluate which mathematical model (monoexponential, biexponential, statistical, kurtosis) fits best to the diffusion-weighted signal in prostate magnetic resonance imaging (MRI).

Materials and Methods

24 prostate 3-T MRI examinations of young volunteers (YV, n= 8), patients with biopsy proven prostate cancer (PC, n= 8) and an aged matched control group (AC, n= 8) were included. Diffusion-weighted imaging was performed using 11 b-values ranging from 0 to 800 s/mm².

Results

Monoexponential apparent diffusion coefficient (ADC) values were significantly (P<.001) lower in the peripheral (PZ) zone (1.18±0.16 mm²/s) and the central (CZ) zone (0.73±0.13 mm²/s) of YV compared to AC (PZ 1.92±0.17 mm²/s; CZ 1.35±0.21 mm²/s). In PC ADC_mono values (0.61±0.06 mm²/s) were significantly (P<.001) lower than in the peripheral of central zone of AC. Using the statistical analysis (Akaike information criteria) in YV most pixels were best described by the biexponential model (82%), the statistical model, respectively kurtosis (93%) each compared to the monoexponential model. In PC the majority of pixels was best described by the monoexponential model (57%) compared to the biexponential model.

Conclusion

Although a more complex model might provide a better fitting when multiple b-values are used, the monoexponential analyses for ADC calculation in prostate MRI is sufficient to discriminate prostate cancer from normal tissue using b-values ranging from 0 to 800 s/mm².     

Optical smart card using semipassive communication

An optical secure short-range communication system is presented. The mobile unit (optical smart card) of this system utilizes a retroreflector with an optical modulator, using light from the stationary unit; this mobile unit has very low power consumption and can be as small as a credit card. Such optical smart cards offer better security than RF-based solutions, yet do not require physical contact. Results from a feasibility study model are included.     

Modern energy density functional for nuclei and the nuclear matter equation of state

We discuss a method of determining a modern energy density functional (EDF) in nuclei. We adopt a Skyrme type EDF and fit the Skyrme parameters to an extensive set of experimental data on the ground-state binding energies, radii, and the breathing mode energies of a wide range of nuclei. We further constrain the values of the Skyrme parameters by requiring positive values for the slope of the symmetry energy S, the enhancement factor κ, associated with the isovector giant dipole resonance, and the Landau parameter G ₀^′. This is done within the approaches of Hartree-Fock (HF) and HF with the inclusion of correlation effects, using a simulated-annealing based algorithm forminimizing χ ².We also present results of HF based random phase approximation for the excitation strength function of the breathing mode and discuss the current status of the nuclear matter incompressibility coefficient.