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Nanoplastics (NPs) are increasingly recognized as pollutants in agricultural systems, yet their impacts on tobacco remain poorly understood. This study systematically investigated the uptake, translocation, and physiological responses of tobacco seedlings exposed to polystyrene (PS, 50 nm) and polylactic acid (PLA, 50 nm) NPs under hydroponic conditions. Both PS and PLA exhibited concentration-dependent effects. Low concentrations (10 mg L −1 ) moderately enhanced biomass accumulation (8.2-24.4%) and photosynthetic performance (21.6-33.5%), whereas high concentrations (100 mg L −1 ) significantly suppressed growth (9.4-30.2%), reduced chlorophyll content (6.0-14.9%), decreased photosystem II efficiency, and increased lipid peroxidation. Confocal microscopy revealed the presence of fluorescently labeled NPs in roots, stems, and leaves, indicating their uptake and translocation within tobacco seedlings. FTIR analysis detected characteristic PS (698 cm −1 ) and PLA (1758 cm −1 ) functional groups in plant tissues and revealed changes in the -OH and C-O-C bands, indicating the occurrence of oxidative stress responses and potential modifications in celluloserelated structures. Overall, the results suggest that NPs adversely affect tobacco growth through integrated mechanisms involving tissue accumulation, redox imbalance, and structural alterations. PLA exerted stronger inhibitory and oxidative effects than PS at the same concentration. These findings advance our understanding of the behavior and phytotoxicity of biodegradable and nonbiodegradable NPs in agricultural environments.

Brain-stimulation reward, also known as intracranial self-stimulation (ICSS), is a commonly used procedure for studying brain reward function and drug reward. In electrical ICSS (eICSS), an electrode is surgically implanted into the medial forebrain bundle (MFB) in the lateral hypothalamus or the ventral tegmental area (VTA) in the midbrain. Operant lever responding leads to the delivery of electrical pulse stimulation. The alteration in the stimulation frequency-lever response curve is used to evaluate the impact of pharmacological agents on brain reward function. If a test drug induces a leftward or upward shift in the eICSS response curve, it implies a reward-enhancing or abuse-like effect. Conversely, if a drug causes a rightward or downward shift in the functional response curve, it suggests a reward-attenuating or aversive effect. A significant drawback of eICSS is the lack of cellular selectivity in understanding the neural substrates underlying this behavior. Excitingly, recent advancements in optical ICSS (oICSS) have facilitated the development of at least three cell type-specific oICSS models—dopamine-, glutamate-, and GABA-dependent oICSS. In these new models, a comparable stimulation frequency-lever response curve has been established and employed to study the substrate-specific mechanisms underlying brain reward function and a drug’s rewarding versus aversive effects. In this review article, we summarize recent progress in this exciting research area. The findings in oICSS have not only increased our understanding of the neural mechanisms underlying drug reward and addiction but have also introduced a novel behavioral model in preclinical medication development for treating substance use disorders.

Although small molecules that act on cannabinoid CB 1 receptor are known to modulate cocaine seeking behavior in rodents, the role of type 2 cannabinoid receptor (CB 2 R) in drug of abuse–related behavior is less clear. Here, Xi and colleagues demonstrate that a selective CB 2 R antagonist inhibits cocaine self-administration in mice by acting through central CB 2 Rs in the nucleus accumbens. The presence and function of cannabinoid CB 2 receptors in the brain have been the subjects of much debate. We found that systemic, intranasal or intra-accumbens local administration of JWH133, a selective CB 2 receptor agonist, dose-dependently inhibited intravenous cocaine self-administration, cocaine-enhanced locomotion, and cocaine-enhanced accumbens extracellular dopamine in wild-type and CB 1 receptor knockout ( CB 1 −/− , also known as Cnr1 −/− ) mice, but not in CB 2 −/− ( Cnr2 −/− ) mice. This inhibition was mimicked by GW405833, another CB 2 receptor agonist with a different chemical structure, and was blocked by AM630, a selective CB 2 receptor antagonist. Intra-accumbens administration of JWH133 alone dose-dependently decreased, whereas intra-accumbens administration of AM630 elevated, extracellular dopamine and locomotion in wild-type and CB 1 −/− mice, but not in CB 2 −/− mice. Intra-accumbens administration of AM630 also blocked the reduction in cocaine self-administration and extracellular dopamine produced by systemic administration of JWH133. These findings suggest that brain CB 2 receptors modulate cocaine's rewarding and locomotor-stimulating effects, likely by a dopamine-dependent mechanism.

The simulations of a heat wave occurring in southern Yangtze-Huaihe valley and southern China during late July, 2003 were conducted to examine the sensitivity of simulated surface air temperature （SAT） to different land surface schemes （LSSs） using the Weather Research and Forecasting Model （WRF） Version 2.2 in the short-range mode for 24-h integrations. Initial and boundary conditions employed a National Centers for Environmental Prediction （NCEP） analysis. The results showed that, overall, simulated high-temperature weather is sensitive to different LSSs. Large differences in simulated SAT intensity, threat score, and simulated error under different schemes are identified clearly. In addition, some systematic differences are also induced by the LSSs. In terms of threat score from the three LSSs, SLAB is the best, and RUC is better than NOAH. SLAB gives the lowest absolute error for area-averaged SAT, and tends to depict the western Pacific subtropical high with the easternmost position at low levels. The LSSs modify the simulated SAT, primarily via the transfer of sensible heat from the land surface to the atmosphere. The physical mechanism of the positive feedback between atmospheric circulation and the SAT is unimportant, with ＂negative＂ feedback over most of the simulated areas. This study emphasizes the importance of improving LSSs in SAT forecasting by numerical models.

Cannabis can be rewarding or aversive. Cannabis reward is believed to be mediated by activation of cannabinoid CB1 receptors (CB1Rs) on GABAergic neurons that disinhibit dopaminergic neurons in the ventral tegmental area (VTA). However, little is known about the mechanisms underlying cannabis aversion in rodents. In the present study, CB1Rs are found not only on VTA GABAergic neurons, but also on VTA glutamatergic neurons that express vesicular glutamate transporter 2 (VgluT2). We then used Cre-Loxp transgenic technology to selectively delete CB1Rs in VgluT2-expressing glutamatergic neurons (VgluT2- CB1 −/− ) and Cre-dependent viral vector to express light-sensitive channelrhodopsin-2 into VTA glutamatergic neurons. We found that photoactivation of VTA glutamatergic neurons produced robust intracranial self-stimulation (ICSS) behavior, which was dose-dependently blocked by DA receptor antagonists, but enhanced by cocaine. In contrast, Δ 9 -tetrahydrocannabinol (Δ 9 -THC), the major psychoactive component of cannabis, produced dose-dependent conditioned place aversion and a reduction in the above optical ICSS in VgluT2-cre control mice, but not in VgluT2- CB1 −/− mice. These findings suggest that activation of CB1Rs in VgluT2-expressing glutamate neurons produces aversive effects that might explain why cannabinoid is not rewarding in rodents and might also account for individual differences in the hedonic effects of cannabis in humans.

The microstructures of the nanocrystalline surface layer of a quenched and high temperature tempered 0. 4C- 1Cr steel induced by high-power surface processing （HPSP） technique were characterized by scan- ning eleetron microscopy and transmission electron microscopy. The results indicate that a nanocrystalline layer was fabricated on the surface of the steel 19 using HPSP treatment. The mean grain size in the surface layer is about 11 nm. The nanocrystallization of cementite is prior to that of the matrix phase, ferrite.

Neuroimaging studies using positron emission tomography suggest that reduced dopamine D ₂ receptor availability in the neostriatum is associated with increased vulnerability to drug addiction in humans and experimental animals. The role of D ₃ receptors (D ₃Rs) in the neurobiology of addiction remains unclear, however. Here we report that D ₃R KO (D ₃⁻/⁻) mice display enhanced cocaine self-administration and enhanced motivation for cocaine-taking and cocaine-seeking behavior. This increased vulnerability to cocaine is accompanied by decreased dopamine response to cocaine secondary to increased basal levels of extracellular dopamine in the nucleus accumbens, suggesting a compensatory response to decreased cocaine reward in D ₃⁻/⁻ mice. In addition, D ₃⁻/⁻ mice also display up-regulation of dopamine transporters in the striatum, suggesting a neuroadaptative attempt to normalize elevated basal extracellular dopamine. These findings suggest that D ₃R deletion increases vulnerability to cocaine, and that reduced D ₃R availability in the brain may constitute a risk factor for the development of cocaine addiction.

Background Sanniang Bay (SNB) and Dafeng River (DFR), located in the northern Beibu Gulf, is well-known as one of the eight habitats for humpback dolphins in China. This region is representative of typical estuarine and bay ecosystems and produce complex hydrodynamic seawater conditions. Moreover, anthropogenic pressure, such as eutrophication and large-scale infrastructure projects, have caused ongoing habitat deterioration and loss. It is urgent to know the phytoplankton community and their relationships with environmental factors in this region. Results In this study, we assessed the diversity and assembly mechanisms of phytoplankton communities, as well as their relationship with the physicochemical characteristics of seawater in SNB and DFR region using 18 S rDNA metabarcoding analysis. The results showed that seasonal changes markedly impacted the alpha diversity of the phytoplankton community. From March to July, with the average temperature increasing from 25.2℃ to 28.1℃,the Shannon or Species Richness were negatively correlated with temperature. During hot season (in Sep, average temperature 32.1℃), phytoplankton diversity was negatively correlated with nutrients (NH 4  + , NO 3 − , PO 4 3− , TN). Additionally, during the rainy season, the Bray-Curtis similarity of the phytoplankton community was significantly lower than during the dry season. In March, the distance among the sampling sites was most strongly and positively correlated with the Bray-Curtis dissimilarity. Stochastic processes, specifically dispersal limitation and ecological drift, are the primary drivers of community assembly, while deterministic assembly processes (mainly heterogeneous selection) contribute a relatively minor portion (< 17%). Conclusions Rising temperature diminished the diversity of phytoplankton in SNB and DFR, and nutrient inputs and eutrophication in estuarine areas will aggravate the loss of phytoplankton diversity.

Agonist-replacement therapies have been successfully used for treatment of opiate and nicotine addiction, but not for cocaine addiction. One of the major obstacles is the cocaine-like addictive potential of the agonists themselves. We report here an atypical dopamine (DA) transporter (DAT) inhibitor, CTDP-32476, that may have translational potential for treating cocaine addiction. In vitro ligand-binding assays suggest that CTDP-32476 is a potent and selective DAT inhibitor and a competitive inhibitor of cocaine binding to the DAT. Systemic administration of CTDP-32476 alone produced a slow-onset, long-lasting increase in extracellular nucleus accumbens DA, locomotion, and brain-stimulation reward. Drug-naive rats did not self-administer CTDP-32476. In a substitution test, cocaine self-administration rats displayed a progressive reduction in CTDP-32476 self-administration with an extinction pattern of drug-taking behavior, suggesting significantly lower addictive potential than cocaine. Pretreatment with CTDP-32476 inhibited cocaine self-administration, cocaine-associated cue-induced relapse to drug seeking, and cocaine-enhanced extracellular DA in the nucleus accumbens. These findings suggest that CTDP-32476 is a unique DAT inhibitor that not only could satisfy 'drug hunger' through its slow-onset long-lasting DAT inhibitor action, but also render subsequent administration of cocaine ineffectual-thus constituting a novel and unique compound with translational potential as an agonist therapy for treatment of cocaine addiction.

Neuroimaging studies using positron emission tomography suggest that reduced dopamine D 2 receptor availability in the neostriatum is associated with increased vulnerability to drug addiction in humans and experimental animals. The role of D 3 receptors (D 3 Rs) in the neurobiology of addiction remains unclear, however. Here we report that D 3 R KO (D 3 −/− ) mice display enhanced cocaine self-administration and enhanced motivation for cocaine-taking and cocaine-seeking behavior. This increased vulnerability to cocaine is accompanied by decreased dopamine response to cocaine secondary to increased basal levels of extracellular dopamine in the nucleus accumbens, suggesting a compensatory response to decreased cocaine reward in D 3 −/− mice. In addition, D 3 −/− mice also display up-regulation of dopamine transporters in the striatum, suggesting a neuroadaptative attempt to normalize elevated basal extracellular dopamine. These findings suggest that D 3 R deletion increases vulnerability to cocaine, and that reduced D 3 R availability in the brain may constitute a risk factor for the development of cocaine addiction.