The Role of Pre-Replication Complex Proteins in Drosophila Ovarian Stem Cell Maintenance and Proliferation

Cancer stem cells (CSCs) may hold the key to advances in cancer research. Like adult tissue-specific stem cells, CSCs are able to self-renew and last a lifetime. These shared characteristics can thus be used to help learn more about CSCs and how they work. More specifically, understanding the molecular mechanisms that control adult tissue-specific stem cell proliferation can lead to better regenerative therapies and a better understanding of CSCs overall. The proliferation of Drosophila ovarian germline stem cells (GSCs), as well as their ability to create differentiated daughters, relies on proper DNA replication. By investigating the regulation of stem cell division, we can advance our knowledge of the fine line between regulated versus unregulated division, and the causes behind each. One of the major components of replication control are the pre-initiation complex (PIC) proteins, which are essential for proper DNA replication. For example, Minichromosome maintenance protein 10 (MCM10) is recruited during the transition from G1 to S-phase, and aids in the recruitment of other PIC proteins to the replication fork. To investigate whether PIC proteins are essential for stem cell function, two comparisons were made. The average number of GSCs per germarium in control and mutant flies were compared. Next EdU staining was utilized to calculate the percentage of GSCs that were in S-phase. Once again, control and mutant percentages were compared to determine if MCM10 mutants affect stem cell function. We demonstrate that the loss of MCM10 results in a reduction in stem cell number and an increase S-phase length which is an indication of an altered cell cycle. Ongoing studies are investigating if stem cell loss in MCM10 mutants is due to DNA damage and to observe the effects of other pre-replication initiation complex mutant proteins. Combined, our data suggests that PIC proteins are critical for stem cell function

Mutual Phase Locking of Very Nonidentical Spin Torque Nanooscillators via Spin Wave Interaction

In this paper the mutual phase locking theory of very nonidentical spin-torque nanooscillators, which is based on the Slavin-Tiberkevich model, considering the theory of nonlinear oscillations, is developed. Using generalized Adler equation we calculate phase-locking region of the system with spinwave coupling in the parameter plane - distance between nanocontacts and radii difference. We describe trajectories of such a system in the phase space and show the effect of a broadband synchronization. We introduce a generalization of this approach to the ensembles of spin-torque nanooscillatorsComment: 6 pages, 2 figure

Powers of sets in free groups

We prove that |A^n| > c_n |A|^{[\frac{n+1}{2}]} for any finite subset A of a free group if A contains at least two noncommuting elements, where c_n>0 are constants not depending on A. Simple examples show that the order of these estimates are the best possible for each n>0.Comment: 3 page

The inter-branch relations of civil law in the exercise of contractual relations regulation on performing work and services

Questions of the law industries interaction are brought up in researches of scientists. However, the due answer about cross-industry communications of the civil law is still absent. Meanwhile there is a need for ensuring balance of civil and labor law regulation of the public relations connected with a labor activity of the person given a contractual shape in the acts and the Constitutional court of the Russian Federation. Development of various forms of communication between people has pushed requirement of providing an opportunity to voluntarily use offered by the legislator or to create legal models in the form of various agreements. The agreement became one of the main methods and instruments of law precepts implementation in public life, the most important means of regulating obligations communications, representing the agreement of its participants without coercion from the outside. In article it is specified that for goal achievement of establishing real system relations regulation on work performance and rendering services it is necessary to provide cross-industry interaction of the civil law with other legal industries, in particular, with labor laws. In this article an author's idea of interaction of the civil law with other industries of the law, contractual regulation, cross-industry communications is analyzed

Control of the nonlinear frequency shift for the spin-transfer nanooscillator using a bias magnetic field

We investigated the possibilities of controlling the nonlinear frequency shift of the magnetization oscillations in a spin-transfer nanoscillator by varying the magnitude and direction of the bias magnetic field. We considered both isotropic ferromagnetic materials and crystals with uniaxial and cubic crystallographic anisotropies. We have shown that achieving a zero nonlinear frequency shift is possible with a certain orientation of the bias magnetic field vector. The results of the theoretical analysis based on the method of Hamiltonian formalism are in good agreement with the micromagnetic simulations. Our research reveals the way to control the frequency tuning of a spin transfer nanoscillator, which is crucial for spintronic signal generation devices.Comment: 6 pages, 3 figure

Noise Properties of Two Mutually Coupled Spin-Transfer Nanooscillators in the Phase Locking Regime

Introduction. Today, many research endeavors are devoted to the miniaturization of microwave sources. One of the promising approaches is the use of magnetic nanostructures (spintronics elements), providing a wide range of frequency tuning and low power consumption. The main disadvantage of spintronics generators (spintransfer nanoscillators ‒ STNO) is a low output power of generated oscillations (tens of nanowatts and less). A possible solution is to sum up the power of many STNOs in a mutual synchronization mode.Aim. The investigation of noise properties of two connected STNOs with identical and non-identical parameters in a phase synchronization mode.Materials and methods. A model was developed of two STNOs interconnected by spin waves taking into account thermal noises. Spectral power densities of the amplitude and phase noise were obtained by the method of effective linearization.Results. Dependencies were obtained in a general form for attenuation coefficients of the amplitude and phase fluctuations of noise sources for each STNO. Three cases of synchronization were considered: completely identical STNOs, two identical STNOs but with different oscillation frequencies, and two non-identical STNOs, differing in an allowance of self-excitation by frequencies and amplitudes of the oscillations. It was possible to obtain a gain in the amplitude and phase noise for two identical STNOs. In this case, an increase in the allowance of self-excitation led to a decrease in the level of phase and amplitude noise.Conclusion. This analysis of the attenuation coefficients for non-identical STNOs demonstrates the possibility of improving the noise properties of each of the generators. In this case, the best noise value is obtained for an STNO with greater stability in a stand-alone mode.Introduction. Today, many research endeavors are devoted to the miniaturization of microwave sources. One of the promising approaches is the use of magnetic nanostructures (spintronics elements), providing a wide range of frequency tuning and low power consumption. The main disadvantage of spintronics generators (spintransfer nanoscillators ‒ STNO) is a low output power of generated oscillations (tens of nanowatts and less). A possible solution is to sum up the power of many STNOs in a mutual synchronization mode.Aim. The investigation of noise properties of two connected STNOs with identical and non-identical parameters in a phase synchronization mode.Materials and methods. A model was developed of two STNOs interconnected by spin waves taking into account thermal noises. Spectral power densities of the amplitude and phase noise were obtained by the method of effective linearization.Results. Dependencies were obtained in a general form for attenuation coefficients of the amplitude and phase fluctuations of noise sources for each STNO. Three cases of synchronization were considered: completely identical STNOs, two identical STNOs but with different oscillation frequencies, and two non-identical STNOs, differing in an allowance of self-excitation by frequencies and amplitudes of the oscillations. It was possible to obtain a gain in the amplitude and phase noise for two identical STNOs. In this case, an increase in the allowance of self-excitation led to a decrease in the level of phase and amplitude noise.Conclusion. This analysis of the attenuation coefficients for non-identical STNOs demonstrates the possibility of improving the noise properties of each of the generators. In this case, the best noise value is obtained for an STNO with greater stability in a stand-alone mode