Search

C12H13N3O, triclinic, P1̄ (no. 2), a = 10.2233(9) Å, b = 10.2902(9) Å, c = 24.2253(19) Å, α = 86.607(7)°, β = 88.529(7)°, γ = 62.515(9)°, V = 2256.9(4) Å3, Z = 8, Rgt(F) = 0.0425, wRref(F2) = 0.1239, T = 291(2) K.

In Caenorhabditis elegans, mitochondrial activity as measured by the frequency of the mitochondrial flash in young adult animals is a powerful predictor of lifespan across genetic, environmental and stochastic factors. Mitoflash activity tests ageing theory The mitochondrial theory of ageing, developed more than 40 years ago based on work on the roundworm Caenorhabditis elegans, proposes that the mitochondria are the main drivers of ageing -- defined as an increase in the probability of death with increasing chronological age. This study is a direct test of the theory using an approach made possible by the recent demonstration that mitochondria undergo stochastic bursts of superoxide production that can be visualized as mitochondrial flashes. The flash frequency of these 'mitoflashes' is sensitive to oxidative stress and metabolic changes. The authors observe that mitoflash activity in the pharyngeal muscles of a 3-day-old adult C. elegans worm inversely correlates with lifespan of the animal. A large variety of genetic mutations and environmental factors inversely modify the lifespan and the mitoflash frequency at day 3. Even within an isogenic population of worms the day-3 mitoflash frequency negatively correlates with lifespan. Day-3 mitoflash frequency is shown to be a powerful predictor of C. elegans lifespan reflecting a range of genetic and environmental influences, suggesting an intimate connection between mitochondrial function and ageing. It has been theorized for decades that mitochondria act as the biological clock of ageing.sup.1, but the evidence is incomplete. Here we show a strong coupling between mitochondrial function and ageing by in vivo visualization of the mitochondrial flash (mitoflash), a frequency-coded optical readout reflecting free-radical production and energy metabolism at the single-mitochondrion level.sup.2,3. Mitoflash activity in Caenorhabditis elegans pharyngeal muscles peaked on adult day 3 during active reproduction and on day 9 when animals started to die off. A plethora of genetic mutations and environmental factors inversely modified the lifespan and the day-3 mitoflash frequency. Even within an isogenic population, the day-3 mitoflash frequency was negatively correlated with the lifespan of individual animals. Furthermore, enhanced activity of the glyoxylate cycle contributed to the decreased day-3 mitoflash frequency and the longevity of daf-2 mutant animals. These results demonstrate that the day-3 mitoflash frequency is a powerful predictor of C. elegans lifespan across genetic, environmental and stochastic factors. They also support the notion that the rate of ageing, although adjustable in later life, has been set to a considerable degree before reproduction ceases., Author(s): En-Zhi Shen [sup.1] [sup.2] , Chun-Qing Song [sup.1] [sup.2] , Yuan Lin [sup.3] , Wen-Hong Zhang [sup.2] , Pei-Fang Su [sup.4] , Wen-Yuan Liu [sup.2] , Pan Zhang [sup.2] [...]

[Display omitted] The nature of the zero-temperature phase diagram of the spin- 1 / 2 J 1 - J 2 Heisenberg model on a square lattice has been debated in the past three decades, and it remains one of the fundamental problems unsettled in the study of quantum many-body theory. By using the state-of-the-art tensor network method, specifically, the finite projected entangled pair state (PEPS) algorithm, to simulate the global phase diagram of the J 1 - J 2 Heisenberg model up to 24 × 24 sites, we provide very solid evidences to show that the nature of the intermediate nonmagnetic phase is a gapless quantum spin liquid (QSL), whose spin-spin and dimer-dimer correlations both decay with a power law behavior. There also exists a valence-bond solid (VBS) phase in a very narrow region 0.56 ≲ J 2 / J 1 ≤ 0.61 before the system enters the well known collinear antiferromagnetic phase. We stress that we make the first detailed comparison between the results of PEPS and the well-established density matrix renormalization group (DMRG) method through one-to-one direct benchmark for small system sizes, and thus give rise to a very solid PEPS calculation beyond DMRG. Our numerical evidences explicitly demonstrate the huge power of PEPS for highly frustrated spin systems. Finally, an effective field theory is also proposed to understand the physical nature of the discovered gapless QSL and its relation to deconfined quantum critical point (DQCP). [ABSTRACT FROM AUTHOR]

Epilepsy, which is caused by abnormal neuronal firing in the brain, is a common neurological disease and affects motor and cognitive functions. Excessive levels of glutamate and insufficient levels of inhibitory GABA are involved in its pathophysiology. Valproic acid (Val), a GABAergic agonist, is one of the first‐line antiepileptic drugs, but it shows many adverse side effects at the clinical dose. Clavulanic acid (CA), a β‐lactamase inhibitor, has been demonstrated to increase glutamate transporter‐1 expression. This study evaluated the effects of CA and Val in an epilepsy rat model. Male Wistar rats received intraperitoneal injections of pentylenetetrazol (PTZ, 35 mg/kg, every other day, IP, for 13 days) to induce kindling epilepsy. After four times of PTZ injection, rats received daily treatment with CA (1 or 10 mg/kg, IP), Val (50 or 100 mg/kg, IP), or the combination of CA (1 mg/kg) and Val (50 mg/kg) for 7 consecutive days. Motor, learning, and memory functions were measured. Rats with PTZ‐induced kindling exhibited seizures, motor dysfunction, cognitive impairment, and cell loss and reduction of neurogenesis in the hippocampus. Neither 1 mg/kg CA nor 50 mg/kg Val treatment was effective in alleviating behavioral and neuronal deficits. However, treatment with 10 mg/kg CA, 100 mg/kg Val, and the combination of 1 mg/kg CA and 50 mg/kg Val improved these behavioral and neuronal deficits. Particularly, the combination of CA and Val showed synergistic effects on seizure suppression, suggesting the potential for treating epilepsy and related neuronal damage and motor and cognitive deficits. [ABSTRACT FROM AUTHOR]

New Findings: What is the central question of this study?Imbalance of activities between GABAergic and glutamatergic systems is involved in epilepsy. It is not known whether simultaneously increasing GABAergic and decreasing glutamatergic activity using valproic acid and ceftriaxone, respectively, leads to better seizure control.What is the central question of this study?Ceftriaxone suppressed seizure and cognitive deficits and restored neuronal density and the number of newborn cells in the hippocampus in a rat model of epilepsy. Combined treatment with ceftriaxone and valproic acid showed additive effects in seizure suppression. The pathophysiology of epilepsy is typically considered as an imbalance between inhibitory GABA and excitatory glutamate neurotransmission. Valproic acid (Val), a GABA agonist, is one of the first‐line antiepileptic drugs in the treatment of epilepsy, but it exhibits adverse effects. Ceftriaxone (CEF) elevates expression of glutamate transporter‐1, enhances the reuptake of synaptic glutamate, increases the number of newborn cells and exhibits neuroprotective effects in animal studies. In this study, we evaluated effects of the combination of CEF and Val on behavioural and neuronal measures in a rat epilepsy model. Male Wistar rats were injected i.p. with pentylenetetrazol (35 mg/kg, every other day for 13 days) to induce the epilepsy model. Ceftriaxone (10 or 50 mg/kg), Val (50 or 100 mg/kg) or the combination of CEF and Val were injected daily after the fourth pentylenetetrazol injection for seven consecutive days. Epileptic rats exhibited seizure and impairments in motor and cognitive functions. Treatment with CEF and Val reduced the seizure and enhanced motor and cognitive functions in a dose‐dependent manner. The combination of CEF (10 mg/kg) and Val (50 mg/kg) improved behaviours considerably. Histologically, compared with control animals, epileptic rats exhibited lower neuronal density and a reduction in hippocampal newborn cells but higher apoptosis in the basolateral amygdala, all of which were restored by the treatment with CEF, Val or the combination of CEF and Val. The study findings demonstrated that the combination of low doses of CEF and Val has beneficial effects on seizure suppression, neuroprotection and improvement in motor and cognitive functions in epilepsy. [ABSTRACT FROM AUTHOR]

Background: Hypoxia appears in a number of extreme environments, including high altitudes, the deep sea, and during aviation, and occurs in cancer, cardiovascular disease, respiratory failures and neurological disorders. Though it is well recognized that hypoxic preconditioning (HPC) exerts endogenous neuroprotective effect against severe hypoxia, the mediators and underlying molecular mechanism for the protective effect are still not fully understood. This study established a hippocampus metabolomics approach to explore the alterations associated with HPC. Methods: In this study, an animal model of HPC was established by exposing the adult BALB/c mice to acute repetitive hypoxia four times. Ultra-high liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-QTOFMS) in combination with univariate and multivariate statistical analyses was employed to deciphering metabolic changes associated with HPC in hippocampus tissue. MetaboAnalyst 3.0 was used to construct HPC related metabolic pathways. Results: The significant metabolic differences in hippocampus between the HPC groups and control were observed, indicating that HPC mouse model was successfully established and HPC could caused significant metabolic changes. Several key metabolic pathways were found to be acutely perturbed, including phenylalanine, tyrosine and tryptophan biosynthesis, taurine and hypotaurine metabolism, phenylalanine metabolism, glutathione metabolism, alanine, aspartate and glutamate metabolism, tyrosine metabolism, tryptophan metabolism, purine metabolism, citrate cycle, and glycerophospholipid metabolism. Conclusion: The results of the present study provided novel insights into the mechanisms involved in the acclimatization of organisms to hypoxia, and demonstrated the neuroprotective mechanism of HPC. [ABSTRACT FROM AUTHOR]

[Display omitted] Alstonia R. Br. (Apocynaceae) is widely used in the traditional therapeutic systems. Due to its rich natural active ingredients, it is used in China, India, Thailand, Malaysia, Philippines, Africa, Australia and other countries to treat malaria, dysentery, asthma, fever, epilepsy, skin diseases, snake bites, and so on. The aim of this review is to describe in detail the botanical properties, traditional uses, chemical compositions, pharmacological activities and toxicity of the genus Alstonia for analyzing the value of this plant in clinical applications. There was information on the genus Alstonia collected through the internet searches such as Baichain Library, Web of Science, China National Knowledge Infrastructure (CNKI), Baidu Scholar, PubMed, Wan Fang Database and ACS, etc. The keywords used include genus Alstonia , folk medicinal uses, botanical studies, chemical composition, pharmacological activities, bioactivities and other relevant terminology. The scientific names and geographic location of the genus Alstonia were provided in the Subject Database of the Flora of China, the Plant List (www.theplantlist.org), the WFO Plant List (www.worldfloraonline.org) and the World Checklist of Selected Plant Families (http://wcsp.science.kew.org/qsearch.do). Currently, at least 400 compounds were isolated from genus Alstonia , including alkaloids, triterpenes, flavonoids, volatile oils, phenolic acids, etc. Through extensive pharmacological experiments, it was demonstrated that genus Alstonia had good pharmacological effects in vitro and in vivo , including β 2 AR, vasodilatory, antifungal, antineoplastic, antiplasmodial, anti-inflammatory, antibacterial, antioxidant, analgesic, and radioprotective activities, etc. Many studies also confirmed that the combination of the genus Alstonia with other traditional Chinese medicines could improve effectiveness. This review demonstrates that the genus Alstonia has high clinical application and medicinal value, which will bring the attention of pharmacologists and clinicians to the territory of natural products Additionally, bioactivity-related mechanisms and structure–activity relationships of chemical components are not clear. Only by bridging the gap between bioactivity-related mechanisms and structure–activity relationships of chemical components can the development of Alstonia plants be further promoted. [ABSTRACT FROM AUTHOR]

C12H13N3O, triclinic, P1̄ (no. 2), a = 10.2233(9) Å, b = 10.2902(9) Å, c = 24.2253(19) Å, α = 86.607(7)°, β = 88.529(7)°, γ = 62.515(9)°, V = 2256.9(4) Å3, Z = 8, Rgt(F) = 0.0425, wRref(F2) = 0.1239, T = 291(2) K. [ABSTRACT FROM AUTHOR]

This paper presents a solution to satisfy the increasing requirements for secure medical image transmission and storage over public networks. The proposed scheme can simultaneously encrypt and compress the medical image using compressive sensing (CS) and pixel swapping based permutation approach. In the CS phase, the plain image is compressed and encrypted by chaos-based Bernoulli measurement matrix, which is generated under the control of the introduced Chebyshev map. The quantized measurements are then encrypted by permutation-diffusion type chaotic cipher for the second level protection. Simulations and extensive security analyses have been performed. The results demonstrate that at a large scale of compression ratio the proposed cryptosystem can provide satisfactory security level and reconstruction quality. [ABSTRACT FROM AUTHOR]

Nowadays, the increasing demand for telemedicine services has raised interest in the real-time medical image protection literatures. In this paper, we evaluate the security of an efficient and secure medical image protection scheme recently proposed (Fu et al., 2013). It is found that this scheme can be successfully broken by launching chosen-plaintext attacks. Improvement is subsequently developed for promoting the security and efficiency performance. Extensive security analyses and experimental results both indicate that the improved scheme can well address the security flaws and advance the speed performance of the original one. [ABSTRACT FROM AUTHOR]