Butterflies are one of the most colorful creatures in animal Kingdom. Wings of the male butterfly are brilliantly colored to
attract females. Color of the wings plays an important role in camouflage. Study of structural colors in case of insects and
butterflies are important for their biomimic and biophotonic applications. Structural color is the color which is produced by
physical structures and their interaction with light.
Paris Peacock or Papilio paris butterfly belongs to the family Papilionidae. The basis of structural color of this butterfly is
investigated in the present study. The upper surface of the wings in this butterfly is covered with blue, green and brown
colored scales. Nano-architecture of these scales was investigated with scanning electron microscope (SEM) and
environmental scanning electron microscope (ESEM). Photomicrographs were analyzed using image analysis software.
Goniometric color or iridescence in blue and green colored scales of this butterfly was observed and studied with the help of
gonio spectrophotometer in the visible range. No iridescence was observed in brown colored scales of the butterfly. Hues of
the blue and green color were measured with spectrophotometer and were correlated with nano-architecture of the wing.
Results of electron microscopy and reflection spectroscopy are used to explain the iridescent nature of blue and green scales.
Sinusoidal grating like structures of these scales were prominently seen in the blue scales. It is possible that the structure of
these wings can act as a template for the fabrication of sinusoidal gratings using nano-imprint technology.
Fourier Transform Infrared Spectroscopy (FTIR) is a very sensitive tool which is capable of providing
strong insight on structural and functional changes in lipids and proteins induced by laser radiation.
In the present work cockroach nervous tissue and chitin from tibia region are irradiated with Nd: YAG
laser (λ= 1064 nm, Power =150mW) via fiber optics (Numerical aperture=0.22, diameter = 8 μ). Nd: YAG laser
exposure time is varied from 10 sec to 50 sec for nervous tissue and chitin. FTIR (Fourier Transform Infra Red
spectra) of cockroach nervous tissue and chitin are compared before and after laser irradiation. The FTIR spectrum
of non irradiated cockroach nervous tissue shows clearly the peaks due to O-H (Carboxylic acid), C=O (Amide I),
C=C (Aromatic), N=0 (Nitro), C-H (Alkenes), CH (Aromatics). FTIR Spectra of non irradiated cockroach chitin
clearly shows O-H (Carboxylic acid), C=O (Carbonyl stretch), C=C (Aromatic), N=O (Nitro), C-O, (anhydrides),
C-H (Alkenes stretch) group.
FTIR spectra of laser radiated nervous tissue from cockroach tibia and chitin shows significant changes in
transmittance for O-H, C=O, C=C, C-H, N=O, C-O and C-H groups. The percentage transmittance increases for
O-H, C=C group for exposure time 10sec, 40sec and 50 sec for nervous tissue. The percentage transmittance
increases for O-H, C=C group for exposure time 10sec, 20sec, 30sec and 40 sec for chitin. The study shows
clearly that FTIR spectroscopy of nervous tissue can reveal the interactions between infrared laser light and
Laser radiation has many applications in biomedical field, such as wound healing, tissue
repairing, heating and ablation processes. Intravenous low power laser radiation is used clinically for skin and vascular
disorders. Laser radiation improves microcirculation and modulates the rheological properties of blood. FTIR (Fourier
Transform Infra Red Spectra) is used to see the structural changes in erythrocyte membrane.
In the present work He Ne laser (λ= 632nm, power=2mW) is used to irradiate human Red blood cells.
Red blood cells are separated from human whole blood using centrifugation method (time=10 min., temperature=15°C
and RPM=3000) and then exposed to HeNe laser radiation. Laser exposure time is varied from 10 min. to 40min for Red
blood cells. Absorption spectrum, FTIR and fluorescence spectra of RBC are compared before and after HeNe laser
irradiation. The absorption spectrum of RBC after exposure to HeNe laser shows a significant decrease in absorbance.
The FTIR spectrum of non irradiated RBC clearly show the peaks due to O-H (free group), C=O (amide I group), N=O
(nitro group), C-O (anhydride group) and C-H (aromatic group). Laser radiation changes in transmittance in FTIR
spectra related to C=O group and percentage of transmittance increases for O-H, C=C, N=O, C-O and C-H group.
We report a method to optically trap and micromanipulate metallic particles using IR laser. The experiment demonstrates
the trapping of metallic particle using low NA objective lens (0.6 N.A). Unlike single beam gradient trapping of
dielectric objects, the optical trapping of metallic particles occurs due to diffraction effect. We thus provide evidence for
non-gradient forces playing a dominant role in the trapping of metallic particles, in here for the case of 3μm Fe particles,
efficient trapping occurs at off-axis position (in the side lobes) of a focused laser beam. The optical trap is characterized
by measuring the external magnetic field required to dislodge the Fe particle, and was found to be 0.03T to 0.11T for
laser power 5 to 55mW at the sample.
The nervous system possesses an intrinsic multiscale organization of processing systems. Evoked potentials (EPs) and other neurometric signals contain corresponding multiscale information about the normal and disordered functioning of the nervous system. The discrete wavelet transform (DWT) explicitly distinguishes among multiple scales of waveform structure, and can be used to decompose EPs in a manner that respects this intrinsic organization. In this paper we provide evidence for the multiscale structure of EPs. We demonstrate that EPs contain scale-specific information of biomedical, neurophysiological, and neuropsychological relevance. Finally, we show that the DWT provides information about small-scale phenomena that is inaccessible by standard neurometric waveform analysis techniques.