Background:Effect of monochromatic green light illumination on embryo development has been reported in chickens.The avian pineal gland is an important photo-endocrine organ formed by a mediodorsal protrusion during em...Background:Effect of monochromatic green light illumination on embryo development has been reported in chickens.The avian pineal gland is an important photo-endocrine organ formed by a mediodorsal protrusion during embryonic development.However,the involvement of pineal gland in the light transduction process remains to be elucidated.In the present study,we investigated the influence of monochromatic green light on hatching time and explored the possible mechanism via pineal function.Results:A total of 600 eggs of White Leghorn(Shaver strain)were incubated under photoperiods of either 12 h of light and 12 h of darkness using monochromatic green light(12L:12D group)or 24 h of darkness(0L:24D group)for 18 d.Compared to 0L:24D group,the green light stimulation shortened the hatching time without extending the hatch window or impairing hatchability.The liver of embryos incubated in the 12L:12D light condition was heavier than those of the 0L:24D group on d 21 post incubation which may be linked to the observed increase in the serum concentration of insulin-like growth factor 1(IGF-1);primary secretion of the liver.Histological structure analysis of pineal gland demonstrated that the light stimulation increased follicle area,wall thickness and lumen area on d 10 and d 12 post incubation.Rhythmic function analysis demonstrated that three clock related genes(brain and muscle ARNT-like-1,BMAL1;circadian locomotor output cycles kaput,CLOCK;and cryptochrome-1,CRY1)and a melatonin rate-limiting enzyme related gene(arylalkylamine N-acetyltransferase,AANAT)were rhythmically expressed in the pineal gland of the 12L:12D group,but not in the 0L:24D group.Simultaneously,the light stimulation also increased the concentration of melatonin(MT),which was linked to hepatocyte proliferation and IGF-1 secretion in previous studies.Conclusions:The 12L:12D monochromatic green light stimulation during incubation shortened hatching time without impairing hatching performance.Pineal gland’s early histological development and maturation of its rhythmic function were accelerated by the light stimulation.It may be the key organ in the photo-endocrine axis that regulates embryo development,and the potential mechanism could be through enhanced secretion of MT in the 12L:12D group which promotes the secretion of IGF-1.展开更多
Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the universe.Countries worldwide have launched numerous space exploration satellites.Accurate calibration of the detect...Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the universe.Countries worldwide have launched numerous space exploration satellites.Accurate calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational results.For the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,P.R.China(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke V.These facilities have a high performance in terms of energy stability,monochromaticity,and flux stability.The monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 h.Calibration experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the facilities.Thus far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in progress.This study will contribute to the advancement of X-ray astronomy the development of Chinese space science.展开更多
AIM: To investigate the value of computed tomography(CT) spectral imaging in the evaluation of intestinal hemorrhage.METHODS: Seven blood flow rates were simulated in vitro.Energy spectral CT and mixed-energy CT scans...AIM: To investigate the value of computed tomography(CT) spectral imaging in the evaluation of intestinal hemorrhage.METHODS: Seven blood flow rates were simulated in vitro.Energy spectral CT and mixed-energy CT scanswere performed for each rate(0.5,0.4,0.3,0.2,0.1,0.05 and 0.025 m L/min).The detection rates and the contrast-to-noise ratios(CNRs) of the contrast agent extravasation regions were compared between the two scanning methods in the arterial phase(AP) and the portal venous phase(PVP).Comparisons of the CNR values between the PVP and the AP were made for each energy level and carried out using a completely random t test.A χ2 test was used to compare the detection rates obtained from the two scanning methods.RESULTS: The total detection rates for energy spectral CT and mixed-energy CT in the AP were 88.57%(31/35) and 65.71%(23/35),respectively,and the difference was significant(χ2 = 5.185,P = 0.023); the total detection rates in the PVP were 100.00%(35/35) and 91.4%(32/35),respectively,and the difference was not significant(χ2 = 1.393,P = 0.238).In the AP,the CNR of the contrast agent extravasation regions was 3.58 ± 2.09 on the mixed-energy CT images,but the CNRs were 8.78 ± 7.21 and 8.83 ± 6.75 at 50 and 60 keV,respectively,on the single-energy CT images,which were significantly different(3.58 ± 2.09 vs 8.78 ± 7.21,P = 0.031; 3.58 ± 2.09 vs 8.83 ± 6.75,P = 0.029).In the PVP,the differences between the CNRs at 40,50 and 60 keV different monochromatic energy levels and the polychromatic energy images were significant(19.35 ± 10.89 vs 11.68 ± 6.38,P = 0.010; 20.82 ± 11.26 vs 11.68 ± 6.38,P = 0.001; 20.63 ± 10.07 vs 11.68 ± 6.38,P = 0.001).The CNRs at the different energy levels in the AP and the PVP were significantly different(t =-2.415,-2.380,-2.575,-2.762,-2.945,-3.157,-3.996 and-3.189).CONCLUSION: Monochromatic energy imaging spectral CT is superior to polychromatic energy images for the detection of intestinal hemorrhage,and the detection was easier in the PVP compared with the AP.展开更多
AIMTo expose rat retinal Müller cells to 530 nm monochromatic light and investigate the influence of varying light illumination times on basic fibroblast growth factor (bFGF) and transforming growth factor...AIMTo expose rat retinal Müller cells to 530 nm monochromatic light and investigate the influence of varying light illumination times on basic fibroblast growth factor (bFGF) and transforming growth factor-β1 (TGF-β1) expression.METHODSThree groups of rat retinal Müller cells cultured in vitro under a 530 nm monochromatic light were divided into 6, 12 and 24h experimental groups, while cells incubated under dark conditions served as the control group. The bFGF and TGF-β1 mRNA expression, protein levels and fluorescence intensity of the Müller cells were analyzed.RESULTSThe bFGF mRNA expression and protein levels were significantly upregulated in Müller cells in all three experimental groups compared with the control group (P<0.05), while that of TGF-β1 was downregulated (P<0.05). Also, bFGF expression was positively correlated, but TGF-β1 expression was negatively correlated with illumination time. The largest changes for both cytokines were seen in the 24h group. The changes in bFGF and TGF-β1 fluorescence intensity were highest in the 24h group, and significant differences were observed among the experimental groups (P<0.05).CONCLUSIONThe expressions of bFGF and TGF-β1 changed in a time-dependent manner in Müller cells exposed to 530 nm monochromatic light with 250 lx illumination intensity. Müller cells might play a role in the development of myopia by increasing bFGF expression or decreasing TGF-β1 expression. Changes in cytokine expression in retinal Müller cells may affect monochromatic light-induced myopia.展开更多
Illuminating conditions are crucial factors affecting the microalgal growth and biosynthesis.The effects of illuminating spectral quality on the growth and bio-component production of Nannochloris oculata were investi...Illuminating conditions are crucial factors affecting the microalgal growth and biosynthesis.The effects of illuminating spectral quality on the growth and bio-component production of Nannochloris oculata were investigated.The results indicated that a high proportion of Red-light enhanced the pigments and carbohydrate production but reduced those of the biomass and lipid.Mono-chromatic Blue-light has advantageous effects on lipid production compared with Red-and White-light.The optimal light spectrum for the protein production was the combination of Red-and Blue-light at a ratio of 4:3 or 5:2.Among the seven fatty acids identified from N.oculata,the contents of C16:0,C18:0,and C18:3(n-3)in the lipid were inhibited by the increased proportion of Red-light while those of C18:2(n-9),C16:2(n-6),and C20:0 were inhibited by Blue-light.Monochromatic Red-and Blue-light and their com-binations were proposed as a promising illuminating strategy for the large-scale cultivation aiming for various bio-components.展开更多
Monochromatic x-ray imaging is an essential method for plasma diagnostics related to density information.Large-field high-resolution monochromatic imaging of a He-like iron(Fe XXV)Kαcharacteristic line(6.701 keV)for ...Monochromatic x-ray imaging is an essential method for plasma diagnostics related to density information.Large-field high-resolution monochromatic imaging of a He-like iron(Fe XXV)Kαcharacteristic line(6.701 keV)for laser plasma diagnostics was achieved using a developed toroidal crystal x-ray imager.A high-index crystal orientation Ge(531)wafer with a Bragg angle of 75.37°and the toroidal substrate were selected to obtain sufficient diffraction efficiency and compensate for astigmatism under oblique incidence.A precise offline assembly method of the toroidal crystal imager based on energy substitution was proposed,and a spatial resolution of 3-7μm was obtained by toroidal crystal imaging of a 600 line-pairs/inch Au grid within an object field of view larger than 1.0 mm.The toroidal crystal x-ray imager has been successfully tested via side-on backlight imaging experiments of the sinusoidal modulation target and a 1000 line-pairs/inch Au grid with a linewidth of 5μm using an online alignment method based on dual positioning balls to indicate the target and backlighter.This paper describes the optical design,adjustment method,and experimental results of a toroidal crystal system in a laboratory and laser facility.展开更多
The problem of in vrivo photoluminescence diagnostics of the tissues acessible by endoscopes is discussed.The spectral imaging module attachable to conventional rigid and flexible medical endoscopes is developed and d...The problem of in vrivo photoluminescence diagnostics of the tissues acessible by endoscopes is discussed.The spectral imaging module attachable to conventional rigid and flexible medical endoscopes is developed and described.It is based on a double acousto-optical tunable filter(AOTF)and a specialized optical coupling system.The module provides wide field of view(FOV),absence of image distortions,random spectral access,fast spectral image acquisition at any wavelength in the visible range and accurate measurement of reflectance spectrum in each pixel of the image.Images of typical biomedical samples are presented and discussed.Their spectra are compared to the reference data.展开更多
The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero degrees.The experimental differential cross...The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero degrees.The experimental differential cross sections of neutron production in the 102 MeV d+C reactions were reproduced by simulations.Based on the consistency between the model prediction and experiment,the feasibility of producing a neutron beam through the breakup of deuteron on a carbon target was demonstrated.Because of the nucleon Fermi motion inside the deuteron,the energy spectrum of the inclusive neutron near 0°in the laboratory exhibits considerable energy broadening in the main peak,whereas the long tail on the low-energy side is suppressed.By coincidentally measuring the accompanying deuteron breakup proton,the energy of the neutron can be tagged with an intrinsic uncertainty of approximately 5%(1σ).The tagging efficiency of the accompanying proton on the forward-emitted neutron can reach 90%,which ensures that the differential cross section in the(d,np)channel remains two orders higher than that in(p,n)after considering the measurement of accompanying protons.This enables the application of a well-defined energy neutron beam in an event-by-event scheme.展开更多
Effects of light intensity and quality of three kinds of LED monochromatic lights (blue, green, and red) on the growth of Skeletonema costatum are investigated in batch culture conditions. Seven light intensities (20,...Effects of light intensity and quality of three kinds of LED monochromatic lights (blue, green, and red) on the growth of Skeletonema costatum are investigated in batch culture conditions. Seven light intensities (20, 30, 40, 45, 50, 60 and 80 μmol·m-2·s-1) are used to evaluate the specific growth rate, spectrum absorption coefficient and saturated light intensity of LED monochromatic light. Results show that the growth rates of Skeletonema costatum increase with the enhanced light intensity;however, the light level beyond the saturation light intensity inhibited the growth of Skeletonema costatum. Compared with red and green light, the growth rate of Skeletonema costatum under blue light is higher within saturated light intensity, and saturated light intensity of LED monochromatic light is lower under blue light and higher under green light. It is concluded that under different monochromatic light, the saturated light intensity decreases and the growth rate increases with the increasing of spectrum absorption coefficient.展开更多
Degradation of Japanese lacquer caused by light irradiation was examined at various wavelengths. By exposing lacquer specimens to a narrow monochromatic light band isolated from dispersed polychromatic light emitted b...Degradation of Japanese lacquer caused by light irradiation was examined at various wavelengths. By exposing lacquer specimens to a narrow monochromatic light band isolated from dispersed polychromatic light emitted by a Xe lamp source, the wavelength sensitivity characteristics of lacquer degradation could be determined on the basis of radiant energy. Tame-Urushi (brown) lacquer displayed peak degradation maxima at 220 and 315 nm. A broad shoulder peak was also observed in UVA. For Shu-Urushi (cinnabar) lacquer, in addition to peaks in the UVA–UVB range, a large degree of degradation was observed following exposure to light in the visible range. Ao-Urushi (green) lacquer showed similar characteristics, although it was less prone to degradation. Similarly, Shin-Urushi (black) lacquer showed little change in response to light, although UV light caused limited degradation. These results indicate that along with the damage caused by UVA and UVB, visible light in the range 510 - 650 nm may also have a significant degradation effect. Our results provide experimental evidence that Japanese lacquer responds differently to light of various wavelengths and that specific wavelengths, including visible light, can cause significant degradation.展开更多
A general scheme for the investigation of scattering by a chiral sphere under arbitrary monochromatic laser beam illumination is presented. The scattered and internal fields are expanded by using appropriate spherical...A general scheme for the investigation of scattering by a chiral sphere under arbitrary monochromatic laser beam illumination is presented. The scattered and internal fields are expanded by using appropriate spherical vector wave functions, and their expansion coefficients are determined by the boundary conditions and the projection method. Targeting multiple incidence forms such as Gaussian beam, Hermite–Gaussian beam, doughnut mode beam and zero-order Bessel beam, the influence and propagation of near-surface intensity field for a chiral sphere are analyzed. These properties are very important for studying the properties of chiral media, and for manipulating the optical tweezers and super-resolution imaging of particles.展开更多
Bollobas and Gyarfas conjectured that for n 〉 4(k - 1) every 2-edge-coloring of Kn contains a monochromatic k-connected subgraph with at least n - 2k + 2 vertices. Liu, et al. proved that the conjecture holds when...Bollobas and Gyarfas conjectured that for n 〉 4(k - 1) every 2-edge-coloring of Kn contains a monochromatic k-connected subgraph with at least n - 2k + 2 vertices. Liu, et al. proved that the conjecture holds when n 〉 13k - 15. In this note, we characterize all the 2-edge-colorings of Kn where each monochromatic k-connected subgraph has at most n - 2k + 2 vertices for n ≥ 13k - 15.展开更多
Let G be an edge-colored graph. The monochromatic tree partition problem is to find the minimum number of vertex disjoint monochromatic trees to cover the all vertices of G. In the authors' previous work, it has been...Let G be an edge-colored graph. The monochromatic tree partition problem is to find the minimum number of vertex disjoint monochromatic trees to cover the all vertices of G. In the authors' previous work, it has been proved that the problem is NP-complete and there does not exist any constant factor approximation algorithm for it unless P= NP. In this paper the authors show that for any fixed integer r ≥ 5, if the edges of a graph G are colored by r colors, called an r-edge-colored graph, the problem remains NP-complete. Similar result holds for the monochromatic path (cycle) partition problem. Therefore, to find some classes of interesting graphs for which the problem can be solved in polynomial time seems interesting. A linear time algorithm for the monochromatic path partition problem for edge-colored trees is given.展开更多
As is well known, coherence does not distinguish the relative phase of a pair of real, sinusoidal time series;the coherence between them is always unity. This behavior can limit the applicability of coherence analysis...As is well known, coherence does not distinguish the relative phase of a pair of real, sinusoidal time series;the coherence between them is always unity. This behavior can limit the applicability of coherence analysis in the special case where the time series are band-limited (nearly-monoch- romatic) and where sensitivity to phase differences is advantageous. We propose a simple mod-ification to the usual formula for coherence in which the cross-spectrum is replaced by its real part. The resulting quantity behaves similarly to coherence, except that it is sensitive to relative phase when the signals being compared are strongly band-limited. Furthermore, it has a useful interpretation in terms of the zero-lag cross-correlation of real band-passed versions of the time series.展开更多
Energy determines the ability of matter to work. However, in the given environment, the real usefulness to perform work is determined by exergy. This study covers not only solar, but also any monochromatic thermal rad...Energy determines the ability of matter to work. However, in the given environment, the real usefulness to perform work is determined by exergy. This study covers not only solar, but also any monochromatic thermal radiation. The value of such radiation was determined by its exergy and the ratio of its exergy-to-energy. A novelty in this work is to demonstrate by means of exergy that the usefulness of thermal polychromatic radiation can be increased by its dispersion to monochromatic radiation. This effect is the greater, the lower the temperature of the radiation. Analogies of this effect to the exergetic effect of gas separation have been indicated. The effect of the increase in exergy in the process of radiation dispersion was interpreted by means of a cylinder-piston system that explains this effect with the influence of environmental radiation. The concept of quasi-monochromatic and cumulated radiation was introduced into dispersion considerations and the change in the energetic, entropic and environmental components of the exergy of radiation beams was analyzed. Considerations were illustrated with appropriate examples of calculations considering dispersion of high-temperature radiation, such as extraterrestrial solar radiation and dispersion of low-temperature radiation from water vapor.展开更多
A probabilistic formalism, relying on Bayes’ theorem and linear Gaussian inversion, is adapted, so that a monochromatic problem can be investigated. The formalism enables an objective test in probabilistic terms of t...A probabilistic formalism, relying on Bayes’ theorem and linear Gaussian inversion, is adapted, so that a monochromatic problem can be investigated. The formalism enables an objective test in probabilistic terms of the quantities and model concepts involved in the problem at hand. With this formalism, an amplitude (linear parameter), a frequency (non-linear parameter) and a hyperparameter of the Gaussian amplitude prior are inferred jointly given simulated data sets with Gaussian noise contributions. For the amplitude, an analytical normal posterior follows which is conditional on the frequency and the hyperparameter. The remaining posterior estimates the frequency with an uncertainty of MHz, while the convolution of a standard approach would achieve an uncertainty of some GHz. This improvement in the estimation is investigated analytically and numerically, revealing for instance the positive effect of a high signal-to-noise ratio and/or a large number of data points. As a fixed choice of the hyperparameter imposes certain results on the amplitude and frequency, this parameter is estimated and, thus, tested for plausibility as well. From abstract point of view, the model posterior is investigated as well.展开更多
Photobleaching of aged traditional Japanese paper that has been thermally yellowed during storage for 200 years was examined from the standpoint of accumulated light radiation dosage in a museum environment. The light...Photobleaching of aged traditional Japanese paper that has been thermally yellowed during storage for 200 years was examined from the standpoint of accumulated light radiation dosage in a museum environment. The light intensity was evaluated using a blue wool reference of the Japan Industrial Standards (JIS) as a dosimeter. The wavelength sensitivity of the photobleaching was compiled under monochromatic light radiation. Color changes in the specimens were measured in tristimuli values in color. by using a color analyzer. The aged pieces of paper were monitored continuously as they were photobleached under three different lighting conditions in a museum environment for 8000 h. The combination of the yellowness index changes of the aged pieces of paper and the color changes of a blue wool reference was interpreted as follows. Photobleaching was governed by accumulated light intensities and was independant upon daily lighting conditions. The wavelength sensitivity of the photobleaching of aged paper showed that the maximum effect occurred at 420 nm in the visible light range. The blue wool reference was confirmed to perform well as a dosimeter.展开更多
We perfected the narrow spectral band fundus photographic system using interference filters at the wavelengths of 417, 478, 500, 530, 547, 570, 589, 607, 628 and 648nm. Tests about the light penetration of filters and...We perfected the narrow spectral band fundus photographic system using interference filters at the wavelengths of 417, 478, 500, 530, 547, 570, 589, 607, 628 and 648nm. Tests about the light penetration of filters and exposure of various brand films were made on this system. Studies of the contrast of fundal tissues and structures under the different narrow spectral band light were made on 43 Chinese fellow eyes. The results indicates that the interference filters of 570 nm have the highest light penetr...展开更多
Objective: Computed tomography (CT)-based attenuation correction (CTAC) offers the clear benefit of reliable reconstruction of single-photon emission computed tomography (SPECT) images through its ability to achieve o...Objective: Computed tomography (CT)-based attenuation correction (CTAC) offers the clear benefit of reliable reconstruction of single-photon emission computed tomography (SPECT) images through its ability to achieve object-specific attenuation maps, but artifacts from dense materials often deteriorate CTAC performance. Therefore, we investigate the feasibility of CTAC in the presence of dense materials using dual-energy virtual monochromatic CT data. Methods: A sodium pertechnetate-filled cylindrical uniform phantom, with a pair of undiluted iodine syringes attached, is scanned with a dual-source CT scanner to obtain both single-energy (120 kVp) polychromatic and dual-energy (80 kVp/140 kVp with tin filtering) virtual monochromatic CT images. The single-energy and the dual-energy CT images are then converted to attenuation maps at 141 keV. SPECT images are reconstructed from 99mTc emission data of the phantom using each single-energy and dual-energy attenuation map and incorporating CTAC procedure. A region-of-in- terest analysis is performed to quantitatively compare the attenuation maps between the single-energy and the dual-energy techniques, each at an iodine-free position and a position adjacent to the iodine solutions. Results: At the iodine-free position, the phantom provides a uniform distribution of attenuation maps in both the single-energy and the dual-energy techniques. In the presence of adjacent iodine solutions, however, severe artifacts appeare in the single-energy CT images. These artifacts make attenuation values fluctuate, resulting in erroneous pixel values in the CTAC SPECT images. In contrast, dual-energy CT strongly suppresses the artifacts and hence improves the uniformity of the attenuation maps and the resultant SPECT images. Conclusions: Dual-energy CT with virtual monochromatic reconstruction has the potential to substantially reduce artifacts arising from dense materials. It has the potential to improve the accuracy of attenuation maps and the resultant CTAC SPECT images.展开更多
This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the m...This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the minority carriers charge in excess. This increase is the consequence of the influence of an electric field provided by the use of the open circuit photovoltage of another silicon solar cell. We assume that it is integrated two silicon solar cells to the system. The first solar cell provides the open circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This work has shown an improvement of the output electric power leading to the increase of the conversion efficiency. We observe an increase of 0.7% of the conversion efficiency of the second silicon solar cell.展开更多
基金Financial support of this study was provided by The National Key Research and Development Program of China(grant number 2016YFD0500502)China Agriculture Research Systems(grant number CARS-40)+1 种基金Fundamental Research Funds for Central Non-profit Scientific Institution(grant number 2018-YWF-YB-20)Agricultural Science and Technology Innovation Program(grant number ASTIP-IAS04).
文摘Background:Effect of monochromatic green light illumination on embryo development has been reported in chickens.The avian pineal gland is an important photo-endocrine organ formed by a mediodorsal protrusion during embryonic development.However,the involvement of pineal gland in the light transduction process remains to be elucidated.In the present study,we investigated the influence of monochromatic green light on hatching time and explored the possible mechanism via pineal function.Results:A total of 600 eggs of White Leghorn(Shaver strain)were incubated under photoperiods of either 12 h of light and 12 h of darkness using monochromatic green light(12L:12D group)or 24 h of darkness(0L:24D group)for 18 d.Compared to 0L:24D group,the green light stimulation shortened the hatching time without extending the hatch window or impairing hatchability.The liver of embryos incubated in the 12L:12D light condition was heavier than those of the 0L:24D group on d 21 post incubation which may be linked to the observed increase in the serum concentration of insulin-like growth factor 1(IGF-1);primary secretion of the liver.Histological structure analysis of pineal gland demonstrated that the light stimulation increased follicle area,wall thickness and lumen area on d 10 and d 12 post incubation.Rhythmic function analysis demonstrated that three clock related genes(brain and muscle ARNT-like-1,BMAL1;circadian locomotor output cycles kaput,CLOCK;and cryptochrome-1,CRY1)and a melatonin rate-limiting enzyme related gene(arylalkylamine N-acetyltransferase,AANAT)were rhythmically expressed in the pineal gland of the 12L:12D group,but not in the 0L:24D group.Simultaneously,the light stimulation also increased the concentration of melatonin(MT),which was linked to hepatocyte proliferation and IGF-1 secretion in previous studies.Conclusions:The 12L:12D monochromatic green light stimulation during incubation shortened hatching time without impairing hatching performance.Pineal gland’s early histological development and maturation of its rhythmic function were accelerated by the light stimulation.It may be the key organ in the photo-endocrine axis that regulates embryo development,and the potential mechanism could be through enhanced secretion of MT in the 12L:12D group which promotes the secretion of IGF-1.
基金upported by the National Key R&D Plan of China(2016YFF0200802)Establishment of a standard device for air kerma in mammography X-rays(ANL1902)。
文摘Space scientific exploration is rapidly becoming the primary battlefield for humankind to explore the universe.Countries worldwide have launched numerous space exploration satellites.Accurate calibration of the detectors on the ground is a crucial element for space science satellites to obtain observational results.For the purpose of providing calibration for various satellite-borne detectors,multiple monochromatic X-rays facilities have been built at the National Institute of Metrology,P.R.China(NIM).These facilities mainly pertain to grating diffraction and Bragg diffraction,and the energy range of the produced monochromatic X-rays is 0.218–301 ke V.These facilities have a high performance in terms of energy stability,monochromaticity,and flux stability.The monochromaticity was greater than 3.0%.The energy stability of the facility is 0.02%at 25 ke V over 8 h,and the flux stability was within 1.0%at 25 ke V over 8 h.Calibration experiments on the properties of satellite-borne detectors,such as energy linearity,energy resolution,detection efficiency,and temperature response,can be conducted at the facilities.Thus far,the calibration of two satellites has been completed by the authors,and the work on three other satellites is in progress.This study will contribute to the advancement of X-ray astronomy the development of Chinese space science.
文摘AIM: To investigate the value of computed tomography(CT) spectral imaging in the evaluation of intestinal hemorrhage.METHODS: Seven blood flow rates were simulated in vitro.Energy spectral CT and mixed-energy CT scanswere performed for each rate(0.5,0.4,0.3,0.2,0.1,0.05 and 0.025 m L/min).The detection rates and the contrast-to-noise ratios(CNRs) of the contrast agent extravasation regions were compared between the two scanning methods in the arterial phase(AP) and the portal venous phase(PVP).Comparisons of the CNR values between the PVP and the AP were made for each energy level and carried out using a completely random t test.A χ2 test was used to compare the detection rates obtained from the two scanning methods.RESULTS: The total detection rates for energy spectral CT and mixed-energy CT in the AP were 88.57%(31/35) and 65.71%(23/35),respectively,and the difference was significant(χ2 = 5.185,P = 0.023); the total detection rates in the PVP were 100.00%(35/35) and 91.4%(32/35),respectively,and the difference was not significant(χ2 = 1.393,P = 0.238).In the AP,the CNR of the contrast agent extravasation regions was 3.58 ± 2.09 on the mixed-energy CT images,but the CNRs were 8.78 ± 7.21 and 8.83 ± 6.75 at 50 and 60 keV,respectively,on the single-energy CT images,which were significantly different(3.58 ± 2.09 vs 8.78 ± 7.21,P = 0.031; 3.58 ± 2.09 vs 8.83 ± 6.75,P = 0.029).In the PVP,the differences between the CNRs at 40,50 and 60 keV different monochromatic energy levels and the polychromatic energy images were significant(19.35 ± 10.89 vs 11.68 ± 6.38,P = 0.010; 20.82 ± 11.26 vs 11.68 ± 6.38,P = 0.001; 20.63 ± 10.07 vs 11.68 ± 6.38,P = 0.001).The CNRs at the different energy levels in the AP and the PVP were significantly different(t =-2.415,-2.380,-2.575,-2.762,-2.945,-3.157,-3.996 and-3.189).CONCLUSION: Monochromatic energy imaging spectral CT is superior to polychromatic energy images for the detection of intestinal hemorrhage,and the detection was easier in the PVP compared with the AP.
文摘AIMTo expose rat retinal Müller cells to 530 nm monochromatic light and investigate the influence of varying light illumination times on basic fibroblast growth factor (bFGF) and transforming growth factor-β1 (TGF-β1) expression.METHODSThree groups of rat retinal Müller cells cultured in vitro under a 530 nm monochromatic light were divided into 6, 12 and 24h experimental groups, while cells incubated under dark conditions served as the control group. The bFGF and TGF-β1 mRNA expression, protein levels and fluorescence intensity of the Müller cells were analyzed.RESULTSThe bFGF mRNA expression and protein levels were significantly upregulated in Müller cells in all three experimental groups compared with the control group (P<0.05), while that of TGF-β1 was downregulated (P<0.05). Also, bFGF expression was positively correlated, but TGF-β1 expression was negatively correlated with illumination time. The largest changes for both cytokines were seen in the 24h group. The changes in bFGF and TGF-β1 fluorescence intensity were highest in the 24h group, and significant differences were observed among the experimental groups (P<0.05).CONCLUSIONThe expressions of bFGF and TGF-β1 changed in a time-dependent manner in Müller cells exposed to 530 nm monochromatic light with 250 lx illumination intensity. Müller cells might play a role in the development of myopia by increasing bFGF expression or decreasing TGF-β1 expression. Changes in cytokine expression in retinal Müller cells may affect monochromatic light-induced myopia.
基金supported by the National Natural Sci-ence Foundation of China(Nos.41776156 and 42177459)the Open-End Funds of Jiangsu Key Laboratory of Ma-rine Bioresources and Environment(No.SH20201206).
文摘Illuminating conditions are crucial factors affecting the microalgal growth and biosynthesis.The effects of illuminating spectral quality on the growth and bio-component production of Nannochloris oculata were investigated.The results indicated that a high proportion of Red-light enhanced the pigments and carbohydrate production but reduced those of the biomass and lipid.Mono-chromatic Blue-light has advantageous effects on lipid production compared with Red-and White-light.The optimal light spectrum for the protein production was the combination of Red-and Blue-light at a ratio of 4:3 or 5:2.Among the seven fatty acids identified from N.oculata,the contents of C16:0,C18:0,and C18:3(n-3)in the lipid were inhibited by the increased proportion of Red-light while those of C18:2(n-9),C16:2(n-6),and C20:0 were inhibited by Blue-light.Monochromatic Red-and Blue-light and their com-binations were proposed as a promising illuminating strategy for the large-scale cultivation aiming for various bio-components.
基金National Natural Science Foundation of China(No.11805212)National Key Research and Development Program of China(No.2019YFE03080200)。
文摘Monochromatic x-ray imaging is an essential method for plasma diagnostics related to density information.Large-field high-resolution monochromatic imaging of a He-like iron(Fe XXV)Kαcharacteristic line(6.701 keV)for laser plasma diagnostics was achieved using a developed toroidal crystal x-ray imager.A high-index crystal orientation Ge(531)wafer with a Bragg angle of 75.37°and the toroidal substrate were selected to obtain sufficient diffraction efficiency and compensate for astigmatism under oblique incidence.A precise offline assembly method of the toroidal crystal imager based on energy substitution was proposed,and a spatial resolution of 3-7μm was obtained by toroidal crystal imaging of a 600 line-pairs/inch Au grid within an object field of view larger than 1.0 mm.The toroidal crystal x-ray imager has been successfully tested via side-on backlight imaging experiments of the sinusoidal modulation target and a 1000 line-pairs/inch Au grid with a linewidth of 5μm using an online alignment method based on dual positioning balls to indicate the target and backlighter.This paper describes the optical design,adjustment method,and experimental results of a toroidal crystal system in a laboratory and laser facility.
基金supported by Grant Nos.13-02-12210 and 14-00-10420 of Russian Foundation of Basic Research.
文摘The problem of in vrivo photoluminescence diagnostics of the tissues acessible by endoscopes is discussed.The spectral imaging module attachable to conventional rigid and flexible medical endoscopes is developed and described.It is based on a double acousto-optical tunable filter(AOTF)and a specialized optical coupling system.The module provides wide field of view(FOV),absence of image distortions,random spectral access,fast spectral image acquisition at any wavelength in the visible range and accurate measurement of reflectance spectrum in each pixel of the image.Images of typical biomedical samples are presented and discussed.Their spectra are compared to the reference data.
基金supported by the National Natural Science Foundation of China(Nos.11961141004,11605119,11965004,12047567,and U1867212)the Jiangsu Natural Science Fund Youth Project(No.BK20160304)+1 种基金China Postdoctoral Science Foundation(No.2017M621818)the Ministry of Science and Technology(No.2020YFE0202001).
文摘The deuteron breakup on heavy targets has been investigated in the framework of an improved quantum molecular dynamics model,focusing on the production of neutrons near zero degrees.The experimental differential cross sections of neutron production in the 102 MeV d+C reactions were reproduced by simulations.Based on the consistency between the model prediction and experiment,the feasibility of producing a neutron beam through the breakup of deuteron on a carbon target was demonstrated.Because of the nucleon Fermi motion inside the deuteron,the energy spectrum of the inclusive neutron near 0°in the laboratory exhibits considerable energy broadening in the main peak,whereas the long tail on the low-energy side is suppressed.By coincidentally measuring the accompanying deuteron breakup proton,the energy of the neutron can be tagged with an intrinsic uncertainty of approximately 5%(1σ).The tagging efficiency of the accompanying proton on the forward-emitted neutron can reach 90%,which ensures that the differential cross section in the(d,np)channel remains two orders higher than that in(p,n)after considering the measurement of accompanying protons.This enables the application of a well-defined energy neutron beam in an event-by-event scheme.
文摘Effects of light intensity and quality of three kinds of LED monochromatic lights (blue, green, and red) on the growth of Skeletonema costatum are investigated in batch culture conditions. Seven light intensities (20, 30, 40, 45, 50, 60 and 80 μmol·m-2·s-1) are used to evaluate the specific growth rate, spectrum absorption coefficient and saturated light intensity of LED monochromatic light. Results show that the growth rates of Skeletonema costatum increase with the enhanced light intensity;however, the light level beyond the saturation light intensity inhibited the growth of Skeletonema costatum. Compared with red and green light, the growth rate of Skeletonema costatum under blue light is higher within saturated light intensity, and saturated light intensity of LED monochromatic light is lower under blue light and higher under green light. It is concluded that under different monochromatic light, the saturated light intensity decreases and the growth rate increases with the increasing of spectrum absorption coefficient.
文摘Degradation of Japanese lacquer caused by light irradiation was examined at various wavelengths. By exposing lacquer specimens to a narrow monochromatic light band isolated from dispersed polychromatic light emitted by a Xe lamp source, the wavelength sensitivity characteristics of lacquer degradation could be determined on the basis of radiant energy. Tame-Urushi (brown) lacquer displayed peak degradation maxima at 220 and 315 nm. A broad shoulder peak was also observed in UVA. For Shu-Urushi (cinnabar) lacquer, in addition to peaks in the UVA–UVB range, a large degree of degradation was observed following exposure to light in the visible range. Ao-Urushi (green) lacquer showed similar characteristics, although it was less prone to degradation. Similarly, Shin-Urushi (black) lacquer showed little change in response to light, although UV light caused limited degradation. These results indicate that along with the damage caused by UVA and UVB, visible light in the range 510 - 650 nm may also have a significant degradation effect. Our results provide experimental evidence that Japanese lacquer responds differently to light of various wavelengths and that specific wavelengths, including visible light, can cause significant degradation.
基金Project supported by the National Natural Science Foundation of China(Grant No.61771385)the Industrial Research of Science and Technology Plan of Shaanxi Province,China(Grant No.2016GY-082)
文摘A general scheme for the investigation of scattering by a chiral sphere under arbitrary monochromatic laser beam illumination is presented. The scattered and internal fields are expanded by using appropriate spherical vector wave functions, and their expansion coefficients are determined by the boundary conditions and the projection method. Targeting multiple incidence forms such as Gaussian beam, Hermite–Gaussian beam, doughnut mode beam and zero-order Bessel beam, the influence and propagation of near-surface intensity field for a chiral sphere are analyzed. These properties are very important for studying the properties of chiral media, and for manipulating the optical tweezers and super-resolution imaging of particles.
基金Supported by the National Natural Science Foundation of China(10701065 and 11101378)Zhejiang Provincial Natural Science Foundation(LY14A010009)
文摘Bollobas and Gyarfas conjectured that for n 〉 4(k - 1) every 2-edge-coloring of Kn contains a monochromatic k-connected subgraph with at least n - 2k + 2 vertices. Liu, et al. proved that the conjecture holds when n 〉 13k - 15. In this note, we characterize all the 2-edge-colorings of Kn where each monochromatic k-connected subgraph has at most n - 2k + 2 vertices for n ≥ 13k - 15.
基金Supported by the National Natural Science Foundation of China,PCSIRT and the"973"Program
文摘Let G be an edge-colored graph. The monochromatic tree partition problem is to find the minimum number of vertex disjoint monochromatic trees to cover the all vertices of G. In the authors' previous work, it has been proved that the problem is NP-complete and there does not exist any constant factor approximation algorithm for it unless P= NP. In this paper the authors show that for any fixed integer r ≥ 5, if the edges of a graph G are colored by r colors, called an r-edge-colored graph, the problem remains NP-complete. Similar result holds for the monochromatic path (cycle) partition problem. Therefore, to find some classes of interesting graphs for which the problem can be solved in polynomial time seems interesting. A linear time algorithm for the monochromatic path partition problem for edge-colored trees is given.
文摘As is well known, coherence does not distinguish the relative phase of a pair of real, sinusoidal time series;the coherence between them is always unity. This behavior can limit the applicability of coherence analysis in the special case where the time series are band-limited (nearly-monoch- romatic) and where sensitivity to phase differences is advantageous. We propose a simple mod-ification to the usual formula for coherence in which the cross-spectrum is replaced by its real part. The resulting quantity behaves similarly to coherence, except that it is sensitive to relative phase when the signals being compared are strongly band-limited. Furthermore, it has a useful interpretation in terms of the zero-lag cross-correlation of real band-passed versions of the time series.
文摘Energy determines the ability of matter to work. However, in the given environment, the real usefulness to perform work is determined by exergy. This study covers not only solar, but also any monochromatic thermal radiation. The value of such radiation was determined by its exergy and the ratio of its exergy-to-energy. A novelty in this work is to demonstrate by means of exergy that the usefulness of thermal polychromatic radiation can be increased by its dispersion to monochromatic radiation. This effect is the greater, the lower the temperature of the radiation. Analogies of this effect to the exergetic effect of gas separation have been indicated. The effect of the increase in exergy in the process of radiation dispersion was interpreted by means of a cylinder-piston system that explains this effect with the influence of environmental radiation. The concept of quasi-monochromatic and cumulated radiation was introduced into dispersion considerations and the change in the energetic, entropic and environmental components of the exergy of radiation beams was analyzed. Considerations were illustrated with appropriate examples of calculations considering dispersion of high-temperature radiation, such as extraterrestrial solar radiation and dispersion of low-temperature radiation from water vapor.
文摘A probabilistic formalism, relying on Bayes’ theorem and linear Gaussian inversion, is adapted, so that a monochromatic problem can be investigated. The formalism enables an objective test in probabilistic terms of the quantities and model concepts involved in the problem at hand. With this formalism, an amplitude (linear parameter), a frequency (non-linear parameter) and a hyperparameter of the Gaussian amplitude prior are inferred jointly given simulated data sets with Gaussian noise contributions. For the amplitude, an analytical normal posterior follows which is conditional on the frequency and the hyperparameter. The remaining posterior estimates the frequency with an uncertainty of MHz, while the convolution of a standard approach would achieve an uncertainty of some GHz. This improvement in the estimation is investigated analytically and numerically, revealing for instance the positive effect of a high signal-to-noise ratio and/or a large number of data points. As a fixed choice of the hyperparameter imposes certain results on the amplitude and frequency, this parameter is estimated and, thus, tested for plausibility as well. From abstract point of view, the model posterior is investigated as well.
文摘Photobleaching of aged traditional Japanese paper that has been thermally yellowed during storage for 200 years was examined from the standpoint of accumulated light radiation dosage in a museum environment. The light intensity was evaluated using a blue wool reference of the Japan Industrial Standards (JIS) as a dosimeter. The wavelength sensitivity of the photobleaching was compiled under monochromatic light radiation. Color changes in the specimens were measured in tristimuli values in color. by using a color analyzer. The aged pieces of paper were monitored continuously as they were photobleached under three different lighting conditions in a museum environment for 8000 h. The combination of the yellowness index changes of the aged pieces of paper and the color changes of a blue wool reference was interpreted as follows. Photobleaching was governed by accumulated light intensities and was independant upon daily lighting conditions. The wavelength sensitivity of the photobleaching of aged paper showed that the maximum effect occurred at 420 nm in the visible light range. The blue wool reference was confirmed to perform well as a dosimeter.
文摘We perfected the narrow spectral band fundus photographic system using interference filters at the wavelengths of 417, 478, 500, 530, 547, 570, 589, 607, 628 and 648nm. Tests about the light penetration of filters and exposure of various brand films were made on this system. Studies of the contrast of fundal tissues and structures under the different narrow spectral band light were made on 43 Chinese fellow eyes. The results indicates that the interference filters of 570 nm have the highest light penetr...
文摘Objective: Computed tomography (CT)-based attenuation correction (CTAC) offers the clear benefit of reliable reconstruction of single-photon emission computed tomography (SPECT) images through its ability to achieve object-specific attenuation maps, but artifacts from dense materials often deteriorate CTAC performance. Therefore, we investigate the feasibility of CTAC in the presence of dense materials using dual-energy virtual monochromatic CT data. Methods: A sodium pertechnetate-filled cylindrical uniform phantom, with a pair of undiluted iodine syringes attached, is scanned with a dual-source CT scanner to obtain both single-energy (120 kVp) polychromatic and dual-energy (80 kVp/140 kVp with tin filtering) virtual monochromatic CT images. The single-energy and the dual-energy CT images are then converted to attenuation maps at 141 keV. SPECT images are reconstructed from 99mTc emission data of the phantom using each single-energy and dual-energy attenuation map and incorporating CTAC procedure. A region-of-in- terest analysis is performed to quantitatively compare the attenuation maps between the single-energy and the dual-energy techniques, each at an iodine-free position and a position adjacent to the iodine solutions. Results: At the iodine-free position, the phantom provides a uniform distribution of attenuation maps in both the single-energy and the dual-energy techniques. In the presence of adjacent iodine solutions, however, severe artifacts appeare in the single-energy CT images. These artifacts make attenuation values fluctuate, resulting in erroneous pixel values in the CTAC SPECT images. In contrast, dual-energy CT strongly suppresses the artifacts and hence improves the uniformity of the attenuation maps and the resultant SPECT images. Conclusions: Dual-energy CT with virtual monochromatic reconstruction has the potential to substantially reduce artifacts arising from dense materials. It has the potential to improve the accuracy of attenuation maps and the resultant CTAC SPECT images.
文摘This manuscript is about a theoretical modelling of conversion efficiency improvement of a typical polycrystalline Si solar cell in 1D assumptions. The improvement is brought by the increase of the collection of the minority carriers charge in excess. This increase is the consequence of the influence of an electric field provided by the use of the open circuit photovoltage of another silicon solar cell. We assume that it is integrated two silicon solar cells to the system. The first solar cell provides the open circuit photovoltage which is connected to two aluminum planar armatures creating a planar capacitor. The second solar cell is placed under the uniform electric field created between the two aluminum armatures. This work has shown an improvement of the output electric power leading to the increase of the conversion efficiency. We observe an increase of 0.7% of the conversion efficiency of the second silicon solar cell.