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Numerous investigations have been carried out on the spectral distribution of the light of different species of fireflies. Here we record the emission spectrum of the Indian species of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera : Lampyridae : Luciolinae) on a color film. Green and red color-sectors, with an intense yellow one in between, appear in this spectrum. Intensity profile of this spectrum reveals a hitherto undetected strong narrow yellow line, which lies within the full-width-at-half maximum (FWHM) of the intensity profile. The spectrum recorded in a high-resolution spectrometer confirms the presence of this sharp intense line. This finding lends support to an earlier drawn analogy between the in vivo emission of the firefly and laser light. 相似文献
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Kumar Deepak Jain Ravikumar Shahjahan Banerjee Sabyasachi Prabhu Shriganesh S. Kumar Ranjan Azad Abul K. Roy Chowdhury Dibakar 《Plasmonics (Norwell, Mass.)》2020,15(6):1925-1934
Plasmonics - We present enhancement of operational bandwidths of planar terahertz metasurfaces by incorporating a complex unit cell that consists of a pair of concentric ring resonators. The inner... 相似文献
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This study was conducted to investigate the effect of alcohols viz., ethanol, methanol and n-butanol at different concentrations not only on the vase life of Calendula officinalis L. cut flowers but also to record changes in metabolites like starch content and amount of sugars, and activities of α-amylase, and antioxidant enzymes like peroxidase and superoxide dismutase as well as lipid peroxidation. Ethanol as holding solution significantly increased the vase life as compared to other treatments or the control. n-Butanol shortened vase life and caused the flower stem to fold, whereas ethanol and methanol individually delayed drying up and petals dried slowly from their tips. Significant increments in solution uptake, moisture content and flower diameter were noticed with 2 % ethanol followed by 2 % methanol. Cut scapes having 2 % ethanol exhibited maximum amount of starch and considerably lower amount of reducing and non-reducing sugars. This treatment not only brings down the specific activities of α-amylase and peroxidase but also decreases the process of lipid peroxidation. Effectiveness of methanol (2 %) is evident just after ethanol application (2 %). Lowest concentrations of ethanol and methanol also show relatively higher level of SOD activity in cut flowers of Calendula officinalis. 相似文献
4.
Chandrasekhar Chanda Angshuman Sarkar Srinivas Sistla Dibakar Chakrabarty 《Biochemical and biophysical research communications》2013
A low molecular weight anti-platelet peptide (6.9 kDa) has been purified from Naja kaouthia venom and was named KT-6.9. MALDI-TOF/TOF mass spectrometry analysis revealed the homology of KT-6.9 peptide sequence with many three finger toxin family members. KT-6.9 inhibited human platelet aggregation process in a dose dependent manner. It has inhibited ADP, thrombin and arachidonic acid induced platelet aggregation process in dose dependent manner, but did not inhibit collagen and ristocetin induced platelet aggregation. Strong inhibition (70%) of the ADP induced platelet aggregation by KT-6.9 suggests competition with ADP for its receptors on platelet surface. Anti-platelet activity of KT-6.9 was found to be 25 times stronger than that of anti-platelet drug clopidogrel. Binding of KT-6.9 to platelet surface was confirmed by surface plasma resonance analysis using BIAcore X100. Binding was also observed by a modified sandwich ELISA method using anti-KT-6.9 antibodies. KT-6.9 is probably the first 3FTx from Indian monocled cobra venom reported as a platelet aggregation inhibitor. 相似文献
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We recorded the in vivo emission and time-resolved spectra of the firefly Luciola praeusta Kiesenwetter 1874 (Coleoptera: Lampyridae: Luciolinae). The emission spectrum shows that the full width at half maximum (FWHM)
value for this particular species is 55 nm, which is significantly narrower than the in vivo half-widths reported till now. The time-resolved spectrum reveals that a flash of about 100 ms duration is, in fact, composed
of a number of microsecond pulses. This suggests that the speed of the enzyme-catalysed chemiluminescence reaction in the
firefly for the emission of light is much faster than was previously believed.
A version of this article has already appeared in an archive Nature Precedings; see 相似文献
7.
Priyangshu Rana Borthakur Simanta Hazarika Pradeep Kumar Gupta Anurup Gohain Barua 《Food biophysics》2013,8(4):297-301
A 405 nm diode laser is used to excite fluorescence of juices of raw and ripe lemons. Emission bands appear approximately at 520 nm and 670 nm. Fluorescence intensity ratio F520/F670 is determined for the two stages. Variation in the fluorescence intensity ratio is observed during the process of ripening or growth of the fruit. Time-resolved spectra at this excitation wavelength reveal two decay times at both the stages at the emission wavelength of 520 nm, and two decay times at the raw stage and one decay time at the ripe stage at 670 nm. 相似文献
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Electron rich 6-[(dimethylamino)methylene]amino uracil 1, undergoes [4+2] cycloaddition reactions with various in situ generated glyoxylate imine and imine oxides 6 to provide novel pyrimido[4,5-d]pyrimidine derivatives of biological significance, after elimination of dimethylamine from the (1:1) cycloadducts and oxidative aromatisation. This procedure provides a convenient method for the direct synthesis of pyrimido[4,5-d]pyrimidines in excellent yields when carried out in the solid state and under microwave irradiations. 相似文献
10.
Priyamvada Acharya William D. Tolbert Neelakshi Gohain Xueji Wu Lei Yu Tongyun Liu Wensheng Huang Chih-chin Huang Young Do Kwon Robert K. Louder Timothy S. Luongo Jason S. McLellan Marie Pancera Yongping Yang Baoshan Zhang Robin Flinko James S. Foulke Jr. Mohammad M. Sajadi Roberta Kamin-Lewis James E. Robinson Lo?c Martin Peter D. Kwong Yongjun Guan Anthony L. DeVico George K. Lewis Marzena Pazgier 《Journal of virology》2014,88(21):12895-12906