Periodic stripe patterns are ubiquitous in living organisms, yet the underlying developmental processes are complex and difficult to disentangle. We describe a synthetic genetic circuit that couples cell density and motility. This system enabled programmed Escherichia coli cells to form periodic stripes of high and low cell densities sequentially and autonomously. Theoretical and experimental analyses reveal that the spatial structure arises from a recurrent aggregation process at the front of the continuously expanding cell population. The number of stripes formed could be tuned by modulating the basal expression of a single gene. The results establish motility control as a simple route to establishing recurrent structures without requiring an extrinsic pacemaker.

Nitrogen vacancy (NV) centres in diamond are attractive as quantum sensors owing to their superb coherence under ambient conditions. However, the NV centre spin resonances are relatively insensitive to some important parameters such as temperature. Here we design and experimentally demonstrate a hybrid nano-thermometer composed of NV centres and a magnetic nanoparticle (MNP), in which the temperature sensitivity is enhanced by the critical magnetization of the MNP near the ferromagnetic-paramagnetic transition temperature. The temperature susceptibility of the NV center spin resonance reached 14 MHz/K, enhanced from the value without the MNP by two orders of magnitude. The sensitivity of a hybrid nano-thermometer composed of a Cu1-xNix MNP and a nanodiamond was measured to be 11 mK/Hz 1/2 under ambient conditions. With such high-sensitivity, we monitored nanometer-scale temperature variation of 0.3 degree with a time resolution of 60 msec. This hybrid nano-thermometer 2 provides a novel approach to studying a broad range of thermal processes at nanoscales such as nano-plasmonics, sub-cellular heat-stimulated processes, thermodynamics of nanostructures, and thermal remanent magnetization of nanoparticles. MAIN TEXT:Nanoscale temperature sensing is important for studying a broad range of phenomena in physics, biology, and chemistry, such as the temperature heterogeneities 1-3 in living cells, heat dissipation in nano circuits 4 , nano-plasmonics, and nano-magnetism (like thermal remanent magnetism of nanoparticles). There have been a number of nanoscale temperature detection schemes 5, 6 , such as scanning thermal microscopy (SThM) 7-9 , SQUID based nano-thermometer 10 , and fluorescence thermometers 11 based on rare-

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Cytochrome P450 enzymes are often responsible for the toxic and carcinogenic effects of toxicants, such as aflatoxin B1 (AFB1). The human hepatic CYP2A6 enzyme mediates the oxidative metabolism of several procarcinogens. In this study, we characterized a partial sequence of CYP2A6 gene from Arbor Acres (AA) broiler and studied its role in AFB1 bioactivation. Moreover, the effect of curcumin on CYP2A6 is illustrated. Six groups of AA broiler were treated for 28 days including the control group (fed only basal diet), curcumin alone-treated group (450 mg/kg feed), the group fed AFB1-contaminated feed (5 mg/kg feed) plus the low (150 mg), medium (300 mg) or high (450 mg) of curcumin, and the group fed AFB1-contaminated diet alone (5 mg/kg feed). After the end of treatment period, liver samples were collected for different analyses. The results revealed that the histopathological examination showed clear signs of liver toxicity in AA broliers in AFB1-fed group, but curcumin-supplementation in feed prevented partially AFB1-induced liver toxicity. Liver and body weights were recorded to study the AFB1 harmful effects. We noted an obvious increase in liver weight and decrease in body weight in AFB1-fed group. But, the administration of curcumin partially ameliorated the increase in liver weight and decrease in body weight in a dose-dependent manner. The results (RT-PCR and Elisa) revealed that mRNA and protein expression level enhanced in AFB1-fed group. Consistently, CYP2A6 enzyme activity also increased in AFB1-fed group, suggesting that AA broiler CYP2A6 actively involved in bioactivation of AFB1. However, curcumin treatment inhibited CYP2A6 at mRNA and protein levels in AFB1 treated AA broiler in a dose-dependent manner. Maximum inhibition of liver CYP2A6 enzyme activity in AA broiler has been achieved at a dose of 450 mg/kg curcumin. This is the first study identifying and confirming the role of CYP2A6 enzyme in AFB1 bioactivation in AA broiler liver (in vivo), and the hepatoprotective role of curcumin via inhibiting CYP2A6 expression and enzyme activity. The study contributed to identify an important CYP enzyme involved in AFB1 bioactivation in broilers and thus could pave the way for the prevention of the harmful effects of AFB1 in broilers.

The current study demonstrated curcumin intervention against AFB-indeuced hepatotoxicity. The hallmarks of autophagy and inflammation were assessed by transmission electron microscopy, RT-PCR and western blot. Besides, normal cellular morphology, autophagosomes were found in control and curcumin control group. In contrast, fragmented and swollen mitochondria, irregular shaped nuclei and fat droplets were visible but autophagosomes disappear in AFB-treated group. The mRNA and protein expression levels of autophagy-related genes indicated that AFB significantly inhibited autophagy and induced inflammation. In addition, Nrf2 and HO-1 mRNA and protein level was significantly (p < 0.05) reduced in AFB-fed group. Intriguingly, dietary curcumin supplementation modulated autophagy through the activation of beclin-1, ATG5, Dynein, LC3a, LC3b-I/II and downregulation of p53 & mTOR expression level. Curcumin significantly ameliorated AFB-induced inflammation. Moreover, curcumin treatment significantly (p < 0.05) elevated AFB-induced decrease in Nrf2 and HO-1 mRNA and protein expression level. In summary, curcumin activated autophagy and ameliorated inflammation involving Nrf2 signaling pathway which may become a new targeted therapy to prevent AFB-induced hepatotoxicity.

As a type of heterogeneous catalyst expected for the maximum atom efficiency, a series of single-atom catalysts (SACs) containing spatially isolated metal single atoms (M-SAs) have been successfully prepared by confining M-SAs in the pore-nanospaces of porphyrinic metal–organic frameworks (MOFs). The prepared MOF composites of M-SAs@Pd-PCN-222-NH2 (M = Pt, Ir, Au, and Ru) display exceptionally high and persistent efficiency in the photocatalytic hydrogen evolution reaction with a turnover number (TON) of up to 21713 in 32 h and a beginning/lasting turnover frequency (TOF) larger than 1200/600 h–1 based on M-SAs under visible light irradiation (λ ≥ 420 nm). The photo-/electrochemical property studies and density functional theory calculations disclose that the close proximity of the catalytically active Pt-SAs to the Pd–porphyrin photosensitizers with the confinement and stabilization effect by chemical binding could accelerate electron–hole separation and charge transfer in pore-nanospaces, thus promoting the catalytic H2 evolution reaction with lasting effectiveness.

Background: This research aims to investigate the evaluation methods of teaching oral implant clinical courses and estimate the effectiveness of a virtual simulation platform. Methods: Eighty second-and third-year undergraduates in Lanzhou University were recruited and randomized to either three experimental groups or one control group. The subjects undertook theoretical examinations to test their basic level of knowledge after training in similarly unified knowledge courses. Each student group then participated in an eight-hour operating training session. An operation test on pig mandible was conducted, followed by a second theoretical examination. The assessment consists of three distinct parts: a subjective operating score by a clinical senior teacher, an implant accuracy analysis in cone-beam computed tomography (angular, apical, and entrance deviation), and comparison of the two theoretical examinations. Finally, students completed a questionnaire gauging their understanding of the virtual simulation. Results: There was no significant difference between the four groups in first theoretical examination (P > 0.05); the second theoretical scores of the V-J and J-V group (62.90 ± 3.70, 60.05 ± 2.73) were significantly higher than the first time (57.05 ± 3.92, P < 0.05), while no difference between the V (57.10 ± 3.66) and J (56.89 ± 2.67) groups was found. Thus, the combination of V-J was effective in improving students' theoretical scores. The V-J and J-V groups had higher scores on operation (73.98 ± 4.58, 71.85 ± 4.67) and showed better implant precision. Conclusion: Virtual simulation education, especially with a jaw simulation model, could improve students' implantology achievements and training. Currently study found that the V-J group may performed better than the J-V group in oral implant teaching.

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