Patients with schizophrenia exhibit deficits in motivation and affect, which suggests an impairment in the reward system. The psychotomimetic drug, phencyclidine (PCP), also induces schizophrenia-like negative symptoms, such as reduced motivation, blunted affect, and social withdrawal in both humans and animals. Previous studies have indicated that the dopaminergic neurons in the ventral tegmental area (VTA) play a pivotal role in the development of reward-associated learning and motivation. However, how PCP affects the activity of VTA neurons during performance of a reward-related task and social interaction with others in unanesthetized animals remains unclear. Here, we recorded the unit activity of VTA neurons in freely moving rats before and after systemic administration of PCP in a classical conditioning paradigm, and during social interaction with an unfamiliar partner. In the classical conditioning task, two different tones were sequentially presented, one of which accompanied electrical stimulation of the medial forebrain bundle as an unconditioned stimulus. After identifying the response properties of recorded neurons in the classical conditioning task and social interaction, animals received an intraperitoneal injection of PCP.Our study demonstrated that most VTA neurons responsive to reward-associated stimuli were also activated during social interaction. Such activation of neurons was considerably suppressed by systemic administration of PCP, thus, PCP may affect the firing activity of VTA neurons that are involved in motivation, learning, and social interaction. Disruption of the response of VTA neurons to reward stimuli and socially interactive situations may be involved in PCP-induced impairments similar to the negative symptoms of schizophrenia.
MicroRNAs (miRs) are a class of non-coding, small RNA molecules that play important roles in gene expression. The aberrant expression of miRs is associated with various human diseases, and miRs have been regarded as biomarkers and therapeutic targets in cancer treatment. In this work, using miR-21 as model target species, an efficiently self-enhanced rolling circle amplification (seRCA)-based biosensing platform was developed for the ultrasensitive detection of cancer-related miRs. In the presence of target, a linear DNA template can be cyclized by ligase and initiate the first RCA (fRCA) reaction. Without any separation step and chemical modification, the fRCA products (fRCAp) are capable of activating the second exponential RCA and produce a much higher fluorescence signal, causing the self-enhancement effect of RCA reaction. Because two different signal amplification processes are introduced, there are two linear dynamic ranges together over 7 orders of magnitude. Target miR can be detected down to 1.0 fM with very high specificity, eliminating the interference from homologous miRs. If a fluorescently modified oligonucleotide probe is involved, the seRCA-based biosensing strategy is able to be employed for the intracellular imaging of cancer-related miR. Significantly, the comparative evaluation demonstrates that the proposed strategy exhibits the impressive capability to execute the miR imaging within cells higher than classical fluorescence in situ hybridization (FISH) method. The newly-developed powerful sensing strategy for the specific miR imaging would offer a unique opportunity to promote molecular biological research, early diagnosis and treatment of human cancers.
Implementation of resource-saving technologies can be based on improving the qualitative characteristics of heat and mass transfer equipment, which is widely used in power engineering, chemical, petrochemical, gas and food industries.One of the most effective ways of interaction between the coolant and the working medium is the direct contact of a gravitationally flowing liquid film and a gas. A promising method for passive intensification of heat and mass transfer between the liquid film and gas is the use of contact surfaces with regular roughness, with capillary-porous or mesh coating of channel walls.The launch and emergency stop of the heat and mass transfer device may generate a transition in the cooling mode of liquid from forced to natural convection. This leads to a change in the conditions of heat and mass transfer, and, consequently, to a change in the parameters of the coolant at the output of the device. In this case, using the dependences obtained for forced convection in the channel leads to a significant error in determining the parameters of the heat carrier. Therefore, in order to design and manufacture heat-mass-transfer units of contact type, one would need the information on the patterns of heat and mass transfer under different operating conditions.An important condition for ensuring the efficiency of contact-type devices is to know the features of the interaction between the liquid and gas mediums. The development of boundary layers in the film and gas leads to the need to allocate the initial thermal region and the stabilized heat and mass transfer region. These factors are not taken into account in the engineering calculation methods that exist today.