120 research outputs found
The measurement of time spent outdoors in child myopia research: a systematic review
The purpose of this article is to summarize the methods most commonly used to measure time spent outdoors and provide a comprehensive review of time and activity recording methods with the aim of encouraging the development of new methods. PubMed, Embase and the Cochrane Library were searched from Jan. 1st, 1990 to Aug. 31th, 2017. Studies including the following specific terms: “outdoor”, “outside”, “outdoor activity”, “outside activity”, “outdoor time”, “outside time”, and “outdoor AND measurement of time spent outdoors” were considered for this review. In total, three kinds of outdoor time measurements were discussed. Questionnaires have the longest history and are the most thoroughly revised instruments for assessing time spent outdoors, but recall bias is their most substantial drawback. Global positioning system (GPS) tracking can distinguish between indoor and outdoor locations, but its utility is limited due to several factors such as subject compatibility. Light exposure measurement devices are newly emerging, but all of these devices require good subject cooperation. Further efforts and exploration are needed to develop better methods and new tools to record exposure to the outdoors in real time. Moreover, inventing a new device by combining two or more types of devices mentioned above and using the latest technology of en ergy supplementation and autoswitching may make the best use of the advantages and bypass the disadvantages of each tool
catena-Poly[[bis(acetato-κO)aquacopper(II)]-μ-5-(pyridin-3-yl)pyrimidine-κ2 N 1:N 5]
In the title compound, [Cu(CH3CO2)2(C9H7N3)(H2O)]n, the CuII ion is pentacoordinated in a square-pyramidal geometry. The N atoms of the two chelating symmetry-related 5-(pyridin-3-yl)pyrimidine ligands and the O atoms of the two monodentate acetate anions are nearly coplanar, with a mean deviation from the least-squares plane of 0.157 (2) Å and the CuII ion is displaced by 0.050 (3) Å from this plane towards the apical water O atom. Bridging through the bis-monodentate 5-(pyridin-3-yl)pyrimidine ligand forms a one-dimensional coordination polymer extending parallel to [010]. In the crystal, O—H⋯O hydrogen bonds link the molecules into a two-dimensional supramolecular structure parallel to (100). The crystal studied was an inversion twin with a 0.57 (3):0.43 (3) domain ratio
The expression of classical swine fever virus structural protein E2 gene in tobacco chloroplasts for applying chloroplasts as bioreactors
Photopic pupil size change in myopic orthokeratology and its influence on axial length elongation
AIM: To explore the photopic pupil size behavior in myopic children undergoing overnight orthokeratology (ortho-k) over 1-year period and its effects on the axial elongation. METHODS: A total of 202 Chinese myopic children were enrolled in this prospective clinical trial. Ninety-five subjects in ortho-k group and eighty-eight subjects in spectacle group completed the 1-year study. Axial length (AL) was measured before enrollment and every 6mo after the start of ortho-k. The photopic pupil diameter (PPD) was determined using the Pentacam AXL and measured in an examination room with lighting of 300-310 Lx. Stepwise multiple linear regression analysis was used to identify variables contribution to axial elongation. RESULTS: Compared with spectacle group, the average 1-year axial elongation was significantly slower in the ortho-k group (0.25±0.27 vs 0.44±0.23 mm, P0.05, Bonferroni correction). The 4.81 mm PPD may be a possible cutoff point in the ortho-k group. Subjects with PPD below or equal to 4.81 mm tended to have smaller axial elongation compared to subjects with PPD above 4.81 mm after 1-year period (t=-3.09, P=0.003). In ortho-k group, univariate analyses indicated that those with older age, greater degree of myopia, longer AL, smaller baseline PPD (PPDbaseline) experienced a smaller change in AL. In multivariate analyses, older age, greater AL and smaller PPDbaseline were associated with smaller increases in AL. In spectacle group, PPD tended to be stable (P>0.05, Bonferroni correction) and did not affect axial growth. CONCLUSION: PPDs experience significantly decreases at 1-month and 3-month ortho-k treatment. Children with smaller PPD tend to experience slower axial elongation and may benefit more from ortho-k
Longitudinal dispersion in wave-current-vegetation flow
The flow, turbulence and longitudinal dispersion in wave-current flow through submerged vegetation are experimentally examined. Laboratory experiments are carried out by superimposing progressive waves on a steady flow through simulated submerged vegetation. The resultant wave-currentvegetation interaction shows strong interfacial shear with increase in velocity due to wave-induced drift. The increase in turbulence in vegetation region is found to be about twice than in no wave case due to the additional mixing by wave motions. Solute experiments are conducted to quantify wavecurrent-vegetation longitudinal dispersion coefficient (WCVLDC) by routing method and by defining length and velocity scales for wave-current-vegetation flow, an empirical expression for WCVLDC has been proposed. Although increase in vertical diffusivity is observed compare to bare-bed channel, the shear effect is stronger which increases the magnitude of WCVLDC. The study can be a guideline to understand the combine hydrodynamics of wave, current and vegetation and to quantify the longitudinal dispersion therein.Экспериментально исследовано влияние растительности в жидкости на течение, интенсивность турбулентности и продольную дисперсию в системе волна – течение. В лабораторных экспериментах в установившемся течении создавались короткие волны, генерируемые волнопродуктором, и имитировалась подводная растительность (вегетация). Зона вегетации располагалась в придонной области и моделировалась системой вертикально подвешенных резиновых жгутов. Обнаружено возникновение больших сдвигов горизонтальной скорости течения в зоне перехода от области вегетации к чистой воде. Турбулентное перемешивание в зоне вегетации в два раза выше, чем в системе волна – течение без вегетации. Подводная растительность приводит к росту дисперсии движения вдоль канала. Увеличение скорости течения вызывает увеличение вертикальных сдвигов скорости и усиление продольной дисперсии. Вертикальное перемешивание с учетом вегетации на два порядка выше, чем при ее отсутствии. Выполнены серии экспериментов с целью количественной оценки влияния вегетации на дисперсию движения вдоль канала в зависимости от скорости течения, его глубины и концентрации подводной растительности. Предложены аппроксимации для экспериментально найденных зависимостей коэффициента продольной дисперсии от параметров задачи
An Updated Search of Steady TeV Ray Point Sources in Northern Hemisphere Using the Tibet Air Shower Array
Using the data taken from Tibet II High Density (HD) Array (1997
February-1999 September) and Tibet-III array (1999 November-2005 November), our
previous northern sky survey for TeV ray point sources has now been
updated by a factor of 2.8 improved statistics. From to
in declination (Dec) range, no new TeV ray point
sources with sufficiently high significance were identified while the
well-known Crab Nebula and Mrk421 remain to be the brightest TeV ray
sources within the field of view of the Tibet air shower array. Based on the
currently available data and at the 90% confidence level (C.L.), the flux upper
limits for different power law index assumption are re-derived, which are
approximately improved by 1.7 times as compared with our previous reported
limits.Comment: This paper has been accepted by hepn
Genomic and oncogenic preference of HBV integration in hepatocellular carcinoma
Hepatitis B virus (HBV) can integrate into the human genome, contributing to genomic instability and hepatocarcinogenesis. Here by conducting high-throughput viral integration detection and RNA sequencing, we identify 4,225 HBV integration events in tumour and adjacent non-tumour samples from 426 patients with HCC. We show that HBV is prone to integrate into rare fragile sites and functional genomic regions including CpG islands. We observe a distinct pattern in the preferential sites of HBV integration between tumour and non-tumour tissues. HBV insertional sites are significantly enriched in the proximity of telomeres in tumours. Recurrent HBV target genes are identified with few that overlap. The overall HBV integration frequency is much higher in tumour genomes of males than in females, with a significant enrichment of integration into chromosome 17. Furthermore, a cirrhosis-dependent HBV integration pattern is observed, affecting distinct targeted genes. Our data suggest that HBV integration has a high potential to drive oncogenic transformation
Impact of the Herbal Medicine Sophora flavescens on the Oral Pharmacokinetics of Indinavir in Rats: The Involvement of CYP3A and P-Glycoprotein
Sophora flavescens is a Chinese medicinal herb used for the treatment of gastrointestinal hemorrhage, skin diseases, pyretic stranguria and viral hepatitis. In this study the herb-drug interactions between S. flavescens and indinavir, a protease inhibitor for HIV treatment, were evaluated in rats. Concomitant oral administration of Sophora extract (0.158 g/kg or 0.63 g/kg, p.o.) and indinavir (40 mg/kg, p.o.) in rats twice a day for 7 days resulted in a dose-dependent decrease of plasma indinavir concentrations, with 55%–83% decrease in AUC0-∞ and 38%–78% reduction in Cmax. The CL (Clearance)/F (fraction of dose available in the systemic circulation) increased up to 7.4-fold in Sophora-treated rats. Oxymatrine treatment (45 mg/kg, p.o.) also decreased indinavir concentrations, while the ethyl acetate fraction of Sophora extract had no effect. Urinary indinavir (24-h) was reduced, while the fraction of indinavir in faeces was increased after Sophora treatment. Compared to the controls, multiple dosing of Sophora extract elevated both mRNA and protein levels of P-gp in the small intestine and liver. In addition, Sophora treatment increased intestinal and hepatic mRNA expression of CYP3A1, but had less effect on CYP3A2 expression. Although protein levels of CYP3A1 and CYP3A2 were not altered by Sophora treatment, hepatic CYP3A activity increased in the Sophora-treated rats. All available data demonstrated that Sophora flavescens reduced plasma indinavir concentration after multiple concomitant doses, possibly through hepatic CYP3A activity and induction of intestinal and hepatic P-gp. The animal study would be useful for predicting potential interactions between natural products and oral pharmaceutics and understanding the mechanisms prior to human studies. Results in the current study suggest that patients using indinavir might be cautioned in the use of S. flavescens extract or Sophora-derived products
Spinal Astrocytic Activation Is Involved in a Virally-Induced Rat Model of Neuropathic Pain
Postherpetic neuralgia (PHN), the most common complication of herpes zoster (HZ), plays a major role in decreased life quality of HZ patients. However, the neural mechanisms underlying PHN remain unclear. Here, using a PHN rat model at 2 weeks after varicella zoster virus infection, we found that spinal astrocytes were dramatically activated. The mechanical allodynia and spinal central sensitization were significantly attenuated by intrathecally injected L-α-aminoadipate (astrocytic specific inhibitor) whereas minocycline (microglial specific inhibitor) had no effect, which indicated that spinal astrocyte but not microglia contributed to the chronic pain in PHN rat. Further study was taken to investigate the molecular mechanism of astrocyte-incudced allodynia in PHN rat at post-infection 2 weeks. Results showed that nitric oxide (NO) produced by inducible nitric oxide synthase mediated the development of spinal astrocytic activation, and activated astrocytes dramatically increased interleukin-1β expression which induced N-methyl-D-aspartic acid receptor (NMDAR) phosphorylation in spinal dorsal horn neurons to strengthen pain transmission. Taken together, these results suggest that spinal activated astrocytes may be one of the most important factors in the pathophysiology of PHN and “NO-Astrocyte-Cytokine-NMDAR-Neuron” pathway may be the detailed neural mechanisms underlying PHN. Thus, inhibiting spinal astrocytic activation may represent a novel therapeutic strategy for clinical management of PHN
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