This article concerns one of the most important problems of brain-computer interfaces (BCI) based on Steady State Visual Evoked Potentials (SSVEP), that is the selection of the a-priori most suitable frequencies for stimulation. Previous works related to this problem were done either with measuring systems that have little in common with actual BCI systems (e.g., single flashing LED) or were presented on a small number of subjects, or the tested frequency range did not cover a broad spectrum. Their results indicate a strong SSVEP response around 10 Hz, in the range 13–25 Hz, and at high frequencies in the band of 40–60 Hz. In the case of BCI interfaces, stimulation with frequencies from various ranges are used. The frequencies are often adapted for each user separately. The selection of these frequencies, however, was not yet justified in quantitative group-level study with proper statistical account for inter-subject variability. The aim of this study is to determine the SSVEP response curve, that is, the magnitude of the evoked signal as a function of frequency. The SSVEP response was induced in conditions as close as possible to the actual BCI system, using a wide range of frequencies (5–30 Hz, in step of 1 Hz). The data were obtained for 10 subjects. SSVEP curves for individual subjects and the population curve was determined. Statistical analysis were conducted both on the level of individual subjects and for the group. The main result of the study is the identification of the optimal range of frequencies, which is 12–18 Hz, for the registration of SSVEP phenomena. The applied criterion of optimality was: to find the largest contiguous range of frequencies yielding the strong and constant-level SSVEP response.

Efforts to construct an effective brain-computer interface (BCI) system based on Steady State Visual Evoked Potentials (SSVEP) commonly focus on sophisticated mathematical methods for data analysis. The role of different stimulus features in evoking strong SSVEP is less often considered and the knowledge on the optimal stimulus properties is still fragmentary. The goal of this study was to provide insight into the influence of stimulus characteristics on the magnitude of SSVEP response. Five stimuli parameters were tested: size, distance, colour, shape, and presence of a fixation point in the middle of each flickering field. The stimuli were presented on four squares on LCD screen, with each square highlighted by LEDs flickering with different frequencies. Brighter colours and larger dimensions of flickering fields resulted in a significantly stronger SSVEP response. The distance between stimulation fields and the presence or absence of the fixation point had no significant effect on the response. Contrary to a popular belief, these results suggest that absence of the fixation point does not reduce the magnitude of SSVEP response. However, some parameters of the stimuli such as colour and the size of the flickering field play an important role in evoking SSVEP response, which indicates that stimuli rendering is an important factor in building effective SSVEP based BCI systems.

The chromosomal organization of two novel repetitive DNA sequences isolated from the Chenopodium quinoa Willd. genome was analyzed across the genomes of selected Chenopodium species. Fluorescence in situ hybridization (FISH) analysis with the repetitive DNA clone 18-24J in the closely related allotetraploids C. quinoa and Chenopodium berlandieri Moq. (2n = 4x = 36) evidenced hybridization signals that were mainly present on 18 chromosomes; however, in the allohexaploid Chenopodium album L. (2n = 6x = 54), cross-hybridization was observed on all of the chromosomes. In situ hybridization with rRNA gene probes indicated that during the evolution of polyploidy, the chenopods lost some of their rDNA loci. Reprobing with rDNA indicated that in the subgenome labeled with 18-24J, one 35S rRNA locus and at least half of the 5S rDNA loci were present. A second analyzed sequence, 12-13P, localized exclusively in pericentromeric regions of each chromosome of C. quinoa and related species. The intensity of the FISH signals differed considerably among chromosomes. The pattern observed on C. quinoa chromosomes after FISH with 12-13P was very similar to GISH results, suggesting that the 12-13P sequence constitutes a major part of the repetitive DNA of C. quinoa.

Rationale: With increasing number of complex medical patients with renal transplant who get pregnant, clinicians need to be aware of abdominal compartment syndrome which may masquerade as acute renal allograft injury in pregnancy. Presenting concerns of the patient: A 34-year-old nulliparous Caucasian female with end-stage renal disease (ESRD) due to type 1 diabetes mellitus who received a simultaneous pancreas-kidney transplant (SPK) in 2006 and then after rejection of renal allograft another, kidney-only allograft from a donation after circulatory death became pregnant in May 2013 with dichorionic, diamniotic twins without reproductive technology, and during pregnancy, she developed two episodes of acute injury to the renal allograft. Diagnoses: End-stage renal disease secondary to type I diabetes, acute renal allograft injury, tacrolimus toxicity, abdominal pain. Interventions (including prevention and lifestyle): She received intravenous hydration, medications contributing to renal failure were held, and pain and nauseas were controlled appropriately. Abdominal compartment syndrome was managed by maintaining intravascular pressure and optimizing regional and systemic vascular perfusion by appropriate fluid balance, evacuating intraluminal contents by decompressing gastrointestinal system, and improving abdominal wall compliance by using appropriate analgesics, sedation, and patient positioning. Outcomes: With advancing pregnancy, the patient developed progressive abdominal pain, nausea, leg edema, and rising creatinine that were not responsive to ongoing therapies and required delivery via Cesarean section at 31 weeks of gestational age. Lessons learned: In the era of increasing number of pregnant renal transplant patients with multiple medical issues, we need organized approach to diagnosis of acute renal allograft injury in pregnancy and we need to consider abdominal compartment syndrome as one of the causes.

The results have shown that in most cases, the dose to the empty bladder is lower than when the bladder is full. Simultaneously, the doses to the bowels increase proportionally in the empty state of the bladder comparing to the full organ. Protection of the bowels, which are more radiosensitive, suggests treating the patients in the full state of the bladder. Early and late bowel toxicity should be investigated to establish clear standards of treatment.