No abstract

Mesolimbic dopamine (DA) systems play a critical role in tobacco addiction driven by nicotine. Nicotine activates midbrain DA neurons and, consequently, elevates DA concentrations in targets, especially in the nucleus accumbens (NAc) of the ventral striatum. The route of drug administration influences the impact of addictive drugs. Here, we examine whether the nature of the administration alters DA neuron activity and DA concentrations in the NAc. Using unhabituated naïve freely moving rats, microdialysis measurements showed that nicotine administered via needle injection caused greater DA release in the NAc than the same dose administered via an implanted chronic cannula. After habituation to the needle injections, however, there was no significant difference in DA signaling between the needle and cannula routes of administration. Consistent with these microdialysis results after habituation, our in vivo tetrode unit recordings showed no significant difference in midbrain DA neuron activity in response to nicotine delivered by needle or cannula as long as predictive cues were avoided.

Charge transport of topological semimetals has been in the focus of intensive investigations because of their non-trivial band topology. Heat transport of these materials, on the other hand, is largely unexplored and remains elusive. Here we report on an observation of unprecedented, giant magnetic quantum oscillations of thermal conductivity in the prototypical Weyl semimetal TaAs. The oscillations are antiphase with the quantum oscillating electronic density of states of a Weyl pocket, and their amplitudes amount to two orders of magnitude of the estimation based on the Wiedemann-Franz law. Our analyses show that all the conventional heat-transport mechanisms through diffusions of propagating electrons, phonons and electron-hole bipolar excitations, are far inadequate to account for these phenomena. Taking further experimental facts that the parallel field configuration favors much higher magneto-thermal conductivity, we propose that the newly proposed chiral zero sound provides a reasonable explanation to these exotic phenomena. More work focusing on other topological semimetals along the same line is badly called for.Charge and heat conductions define two entangled fundamental transport properties of a conducting solid. Controllable manipulations of both are essential for various functionalities of pertinent materials. For the recently discovered topological semimetals, electrical transport has revealed distinct topologically nontrivial properties, like the chiral anomaly in the longitudinal magneto-resistance (MR) [1][2][3][4]. On the other hand, thermal transport, in particular thermal conductivity, has remained largely unexplored. This is mainly due to the technical difficulties of precise thermal management at low temperatures. In addition, such work has been so far considered 1 uninteresting because the thermal conductivity may be estimated from the electrical conductivity through the Wiedemann-Franz (WF) law.Indeed, for most electrical conductors, the WF law can provide a straightforward and reliable approach to the electronic contribution κ e of the thermal conductivity based on the electrical conductivityσ, κ e /T = σ L 0 , (1) with the Sommerfeld value of Lorenz number L 0 ≡ π 2 /3 (k B /2) 2 = 2.44 x 10 -8 W⋅Ω⋅K -2 . The WF law holds in the case of dominant elastic scattering, e.g., from static defects as realized at sufficiently low temperatures [5]. Within the last few years, it was also found that the charge and heat conductions of the relativistic Dirac/Weyl fermions may deviate from the WF law [6][7][8][9][10][11]. For example, it was shown very recently that hydrodynamic transport by relativistic Weyl fermions in a Weyl semimetal WP 2 can lead to L/L 0 < 1 in the temperature range T < 200 K [10]. On the other hand, for the electron-hole plasma at the charge-neutrality point in graphene, considered to form a strongly coupled Dirac fluid, hydrodynamic transport was found between T = 50 and 80 K to result in a much enhanced Lorenz number L ≈ 22 L 0 [11].

A new macrolactin derivate, 7-O-2'E-butenoyl macrolactin A (1), together with three known macrolactin compounds, macrolactin A (2), 7-O-malonyl macrolactin A (3) and 7-O-succinyl macrolactin A (4), was isolated from the bacterial strain Bacillus subtilis B5, which was isolated from the 3000 m deep sea sediment of the Southwest Pacific Ocean. The structures of the new compounds were assigned by spectroscopic methods including 1-D/2-D NMR and MS analysis techniques. Compounds 1 and 2 demonstrated antifungal activities against tea pathogenic fungi Pestalotiopsis theae and Colletotrichum gloeosporioides .

Parkinson’s disease (PD) is a chronic and progressive neurodegenerative disease caused by degeneration of dopaminergic neurons in the substantia nigra. Existing pharmaceutical treatments offer alleviation of symptoms but cannot delay disease progression and are often associated with significant side effects. Clinical studies have demonstrated that acupuncture may be beneficial for PD treatment, particularly in terms of ameliorating PD symptoms when combined with anti-PD medication, reducing the required dose of medication and associated side effects. During early stages of PD, acupuncture may even be used to replace medication. It has also been found that acupuncture can protect dopaminergic neurons from degeneration via antioxidative stress, anti-inflammatory, and antiapoptotic pathways as well as modulating the neurotransmitter balance in the basal ganglia circuit. Here, we review current studies and reflect on the potential of acupuncture as a novel and effective treatment strategy for PD. We found that particularly during the early stages, acupuncture may reduce neurodegeneration of dopaminergic neurons and regulate the balance of the dopaminergic circuit, thus delaying the progression of the disease. The benefits of acupuncture will need to be further verified through basic and clinical studies.