Role of Medial Prefrontal Cortical Group II Metabotropic Glutamate Receptor in the Development of Cocaine Sensitization

The current studies examined the role of medial prefrontal cortical (mPFC) group II metabotropic glutamate receptors (mGluR2/3) in the development of cocaine sensitization. Initial studies demonstrated that intra-mPFC injection of the mGluR2/3 receptor agonist, APDC, dose-dependently reduced acute behavioral response to cocaine (0.015-15 nmol/side with significant effects starting at 1.5nmol/side). The effects of APDC were prevented by intra-mPFC co-injections of an mGluR2/3 antagonist, LY341495 (1.5 nmol/side). Repeated intra-mPFC APDC (1.5 nmol/side) injections also prevented the initiation of behavioral and neurochemical sensitization, which is defined as enhanced nucleus accumbens (NAc) dopamine response to cocaine. Once sensitization was induced, however, intra-mPFC administration of APDC did not block cocaine-induced behavioral and neurochemical responses in sensitized animals after 7 days and 30 days withdrawal. In contrast, intra-mPFC injections of APDC were found to block the expression of behavioral and neurochemical sensitization in sensitized animals after 1 day withdrawal. Additional microdialysis studies demonstrated that intra-mPFC infusions of LY341495 increased glutamate levels in the mesocorticolimbic brain regions of control animals, while this response was enhanced in sensitized animals following short term withdrawal from repeated cocaine exposure. The mesocorticolimbic brain regions examined in these studies include the mPFC, NAc and VTA, which are well known brain regions involved in cocaine sensitization. Nonetheless, this effect was no longer apparent in animals after prolonged withdrawal (7 days and 30 days). Furthermore, additional results demonstrated that repeated cocaine exposure enhanced the vesicular (K+ evoked) and non-vesicular (cystine evoked) glutamate release in the mPFC. It was shown that LY379268, an mGluR2/3 receptor agonist, inhibited the K+ induced glutamate release and cystine induced glutamate release in the mPFC of animals following 1 day of withdrawal from repeated cocaine injections. In contrast to these data, LY 379268 did not inhibit the release of glutamate from one of these sources in the mPFC of animals following 7 day of withdrawal. Collectively, these data suggested that the mPFC mGluR2/3 receptor can reduce the motor response to cocaine. The development of cocaine sensitization may be associated with an initial increased responsiveness of the mPFC mGluR2/3 receptor, coupled with enhanced glutamate transmission in the mPFC. Following prolonged withdrawal, loss of inhibitory control of the glutamate release within mPFC by the mGluR2/3 receptor thereafter may result in the enhanced excitatory drive, which in turn generates increased excitatory output from mPFC to subcortical regions including NAc and VTA

BSG alignment of SDSS galaxy groups

We study the alignment signal between the distribution of brightest satellite galaxies (BSGs) and the major axis of their host groups using SDSS group catalog constructed by Yang et al. (2007). After correcting for the effect of group ellipticity, a statistically significant (~ 5\sigma) major-axis alignment is detected and the alignment angle is found to be 43.0 \pm 0.4 degrees. More massive and richer groups show stronger BSG alignment. The BSG alignment around blue BCGs is slightly stronger than that around red BCGs. And red BSGs have much stronger major-axis alignment than blue BSGs. Unlike BSGs, other satellites do not show very significant alignment with group major axis. We further explore the BSG alignment in semi-analytic model (SAM) constructed by Guo et al. (2011). We found general good agreement with observations: BSGs in SAM show strong major-axis alignment which depends on group mass and richness in the same way as observations; and none of other satellites exhibit prominent alignment. However, discrepancy also exists in that the SAM shows opposite BSG color dependence, which is most probably induced by the missing of large scale environment ingredient in SAM. The combination of two popular scenarios can explain the detected BSG alignment. The first one: satellites merged into the group preferentially along the surrounding filaments, which is strongly aligned with the major axis of the group. The second one: BSGs enter their host group more recently than other satellites, then will preserve more information about the assembling history and so the major-axis alignment. In SAM, we found positive evidence for the second scenario by the fact that BSGs merged into groups statistically more recently than other satellites. On the other hand, although is opposite in SAM, the BSG color dependence in observation might indicate the first scenario as well.Comment: 8 pages, 11 figures, ApJ accepte

T2I-Adapter: Learning Adapters to Dig out More Controllable Ability for Text-to-Image Diffusion Models

The incredible generative ability of large-scale text-to-image (T2I) models has demonstrated strong power of learning complex structures and meaningful semantics. However, relying solely on text prompts cannot fully take advantage of the knowledge learned by the model, especially when flexible and accurate structure control is needed. In this paper, we aim to ``dig out" the capabilities that T2I models have implicitly learned, and then explicitly use them to control the generation more granularly. Specifically, we propose to learn simple and small T2I-Adapters to align internal knowledge in T2I models with external control signals, while freezing the original large T2I models. In this way, we can train various adapters according to different conditions, and achieve rich control and editing effects. Further, the proposed T2I-Adapters have attractive properties of practical value, such as composability and generalization ability. Extensive experiments demonstrate that our T2I-Adapter has promising generation quality and a wide range of applications.Comment: Tech Report. GitHub: https://github.com/TencentARC/T2I-Adapte

Estimating Young’s Modulus of Materials by a New Three-Point Bending Method

A new test method based on the three-point bending test is put forward to measure Young’s modulus of materials. The simplified mechanical model is established to make theoretical derivation. This method has not only the advantages of simple specimen preparation and convenient loading device, but also higher precision than the traditional three-point bending method. The method is adopted to obtain Young’s modulus of the aluminum alloy 2024. The feasibility of the method has been demonstrated by comparisons with the corresponding results obtained from the finite element method and experiment method. And the influence of contact friction on the test accuracy is analyzed