No abstract

Participants performed a physical comparison task of pairs of positive and pairs of negative one-digit numbers while their electrophysiological brain activity was measured. The numerical value of the presented digits was either congruent or incongruent with the physical size of the digits. Analysis has shown that the earliest event-related potential (ERP) difference between positive and negative numbers was found in the P300 ERP component peak, where there was an inverse effect of congruity in the negative pairs, compared with the positive ones. This pattern of results supports the idea that natural numbers serve as primitives of the human cognitive system, whereas negative numbers are apparently generated if needed.

Обсуждается методика синтеза микроволновых усилителей мощности на транзисторах с гетеропереходом AlGaN/GaN. Основное внимание уделено разработке методики синтеза трансформирующих цепей усилителя мощности с целью увеличения коэффициента полезного действия при сохранении высокого уровня выходной мощности. Используется независимое согласование на частотах гармоник и на фундаментальной частоте, что позволяет управлять значением достижимого коэффициента полезного действия в широкой полосе частот наряду с полным подавлением гармоник за пределами рабочей полосы. Разработаны и экспериментально исследованы микроволновые усилители мощности на 4 и 9 GHz.

Mouse N18TG2 neuroblastoma and rat C6 glioma cell lines were injected into male nude mice, and the tumors were passaged serially. At each generation, tumors were analyzed for δ opioid binding using [3H][d‐Ala2,d‐Leu5]enkephalin and for σ1 and σ2 binding with 1,3‐[3H]di‐o‐tolylguanidine in the presence and absence of 1 µM pentazocine. Receptor density (Bmax) and affinity (KD) were estimated by homologous competition binding assays. Opioid and σBmax values in the solid tumors were significantly lower than their original levels in vitro. KD values for opioid/σ ligands were similar in vitro and in vivo. With successive passages in the murine host, δ opioid and σ1 binding of the neuroblastoma‐derived solid tumors became undetectable. In contrast, σ2 receptor Bmax values were unchanged with successive passages of the neuroblastoma‐derived tumors and doubled in the nude mouse‐borne gliomas. When neuroblastoma‐derived solid tumors that were devoid of δ opioid binding were returned to culture, opioid receptors appeared to be up‐regulated as compared with their original in vitro levels. Serial passaging of these recultured cells in vivo again resulted in a rapid decline in opioid receptor content. The opioid data are consistent with our prior findings on opioid binding diminution in human brain tumors. The pattern of change for σ binding was more complex, with the σ2 response in late passages of the glioma being reminiscent of the formerly observed increase in number of σ sites in transformed human meninges, kidney, and colon tissue.

The demonstrator of a steerable reflect-array antenna was designed as a system of dipoles loaded by varactor diodes. The microwave response of a dipole loaded by varactor has been simulated in closed form based on equivalent circuit approach. The circuit analytical model has been verified by the full-wave analysis. Change of the varactor capacitance in the range of 0.3-1.3 pF was provided by biasing voltage 0-20 V. The array consists of 20 dipoles structured as two parallel lines. The operational frequency is 11 GHz, the length of the dipole is 9.2 mm, spacing between dipoles is 18 mm. The double-side metallized PTFE with ε = 2.8 and thickness of 1 mm was used as a substrate. Dipole structure was manufactured by a photolithographic process and formed with surface mounted varactor diodes. The radiation pattern of the array is characterized by the width of the main beam ≈ 8 • , the side lobe level-(12 ÷ 20) dB, the steering range ±15 •. Control voltage was set manually with variable resistors separately for each varactor. The fine alignment of the control voltage for each varactors turned out to be very important. Inherited data are used for correction of the operational principle of a varactor steerable antenna controller.