Collective (elementary) excitations of quantum bosonic condensates, including condensates of exciton polaritons in semiconductor microcavities, are a sensitive probe of interparticle interactions. In ...anisotropic microcavities with momentum-dependent transverse-electric–transverse-magnetic splitting of the optical modes, the excitations' dispersions are predicted to be strongly anisotropic, which is a consequence of the synthetic magnetic gauge field of the cavity, as well as the interplay between different interaction strengths for polaritons in the singlet and triplet spin configurations. Here, by directly measuring the dispersion of the collective excitations in a high-density optically trapped exciton-polariton condensate, we observe excellent agreement with the theoretical predictions for spinor polariton excitations. We extract the interaction constants for polaritons of the same and opposite spin and map out the characteristic spin textures in an interacting spinor condensate of exciton polaritons.
Optical trapping has been proven to be an effective method of separating exciton-polariton condensates from the incoherent high-energy excitonic reservoir located at the pumping laser position. This ...technique has significantly improved the coherent properties of exciton-polariton condensates, when compared to a quasi-homogeneous spot excitation scheme. Here, we compare two experimental methods on a sample, where a single spot excitation experiment allowed us only to observe photonic lasing in the weak coupling regime. In contrast, the ring-shaped excitation resulted in the two-threshold behavior, where an exciton-polariton condensate manifests itself at the first and photon lasing at the second threshold. Both lasing regimes are trapped in an optical potential created by the pump. We interpret the origin of this confining potential in terms of repulsive interactions of polaritons with the reservoir at the first threshold and as a result of the excessive free-carrier induced refractive index change of the microcavity at the second threshold. This observation offers a way to achieve multiple phases of photonic condensates in samples, e.g., containing novel materials as an active layer, where two-threshold behavior is impossible to achieve with a single excitation spot.
Collective (elementary) excitations of quantum bosonic condensates, including condensates of exciton polaritons in semiconductor microcavities, are a sensitive probe of interparticle interactions. In ...anisotropic microcavities with momentum-dependent TE-TM splitting of the optical modes, the excitations dispersions are predicted to be strongly anisotropic, which is a consequence of the synthetic magnetic gauge field of the cavity, as well as the interplay between different interaction strengths for polaritons in the singlet and triplet spin configurations. Here, by directly measuring the dispersion of the collective excitations in a high-density optically trapped exciton-polariton condensate, we observe excellent agreement with the theoretical predictions for spinor polariton excitations. We extract the inter- and intra-spin polariton interaction constants and map out the characteristic spin textures in an interacting spinor condensate of exciton polaritons.
The number of arteries providing blood supply for the thyroid gland as well as the origin of the superior thyroid and inferior thyroid arteries were examined in 132 fetuses from single pregnancies ...and in 144 fetuses from twin pregnancies, aging 4 to 9 months. Most frequently (81% cases) four thyroid arteries were observed. Five thyroid arteries were noted in 14.4% cases. Sources of additional thyroid arteries were described.
Abstract Background Hospital training called ETPOD—Essentials in Organ Donation—was introduced in Poland in 31 hospitals with under-utilized potential of donation. The aim of this study was to assess ...the effect in hospitals included and not included in program, before and after trainings. Methods The number of potential and effective donors, organs used, and number (%) of family refusals were compared at 10 and in 20 months after the training and in equal periods before. Results In trained hospitals, the number of potential donors increased (17% in 10 months, 10% in 20 months); in remaining hospitals, donors increased in 5% in both periods. In hospitals included in ETPOD, the number of effective donors increased (2% and 4.5%); in the whole country, donors also increased (5.6% and 2.7%). In ETPOD hospitals, the number of utilized organs increased (14.5% and 8.5%); in the rest, the increase was 3% and 7%. In trained hospitals, family refusals increased from 6.9% to 16.2% and from 8.9% to 10.7%; in the whole country, family refusals decreased from 11.7% to 11% in the short term and increased from 9.6% to 12.1% in the long term. Conclusions In hospitals involved in the ETPOD program, the increase in organ donation is greater than in the rest of hospitals. Distinct benefit was observed in consent to organ donation.
Generation Z is the crucial cohort that will have to face the issues resulting from human impacts on the environment. The oldest members of this generation are now entering adulthood. Even though ...Generation Z is a global and homogeneous cohort, research indicates that the type of settlement unit where one lives may condition the emergence of intra-generational differences. The study focused on determining the pro-environmental behaviour (PEB) of Generation Z from the perspective of a former-socialist European country, Poland. We explored the motivational factors of Polish Generation Z towards their PEB and the actual PEB they undertake. We conducted focus-group interviews with 68 representatives of Generation Z, aged 16–19, living in villages, small towns, and medium-sized and large cities. The data obtained from the interviews were analysed in NVivo software by means of content analysis. Using the Theory of Planned Behaviour, we showed that the type of settlement unit determines pro-environmental attitudes and barriers to undertaking pro-environmental behaviour.
CREB activation and CREB-dependent signaling pathways are crucial for neuronal survival. The term ICER (inducible cAMP early repressor) refers to four protein isoforms that are all endogenous, ...inducible antagonists of CREB. It was previously shown, that all 4 ICER isoforms are induced upon pro-apoptotic treatment, and also that each of them separately evokes neuronal cell death in cortical culture transfected with these genes. The ICER proteins are believed to be strong repressors of Immediate Early Genes, which are involved in cell response to inter- and/or intra-cellular signals. Herein, we have applied the siRNA approach to silence ICER expression. Because ICERs are members of CREM family of proteins, sharing with them the gene sequence, only the small unique region for ICER was selected to design ICER-directed, specific siRNA. Indeed, we obtained functional siRNA capable of blocking ICERs but not affecting CREM proteins. With this tool, we have investigated if the ICER's silencing protects neurons from apoptosis caused by either serum deprivation or excitotoxicity. Using the lentiviral vector, as a vehicle to deliver siRNA (shRNA) we have found that silencing of ICER mildly, although significantly, protects primary cortical neurons from apoptosis caused by serum deprivation.
PDF
