Evaluation of mammary cancer in 7,12-dimethylbenz(a)anthracene-induced Wister rats by asymmetrical temperature distribution analysis using thermography: a comparison with serum CEA levels and histopathology.

Animal surface temperature profile captured using infrared camera is helpful for the assessment of physiological responses associated with the regulation of body temperature. Diagnosing breast cancer in early stage itself has a greater effect on the prognosis. In this work, asymmetrical temperature distribution analysis of chemical carcinogen 7,12-dimethyl benz(a)anthracene-induced in the lower right flank region of Wistar rats (n = 6) was carried out to test the potential of thermography in diagnosing mammary cancer and tumor growth over a period of nine weeks in comparison with histopathology results as standard. Temperature difference between the tumor induced lower right and left side of flank region was significant (with P value <0.001), whereas in the abdomen and shoulder there was no significant difference in temperature between right and left sides. Percentage of asymmetrical temperature difference in the tumor induced lower flank region was 0.5 to 2%, whereas in the other regions it was <0.5%. Green pixel distribution in RGB color histogram was asymmetrical in the tumor induced lower flank region. Temperature reduction was observed in the tumor induced region after the seventh day of carcinogen induction. Asymmetrical thermogram analysis is the best method of diagnosing mammary cancer and for studying tumor development.

Preparation of N-vanillyl chitosan and 4-hydroxybenzyl chitosan and their physico-mechanical, optical, barrier, and antimicrobial properties.

Chitosan derivatives such as N-vanillyl chitosan and 4-hydroxybenzyl chitosan were prepared by reacting chitosan with 4-hydroxy-3-methoxybenzaldehyde (vanillin) and 4-hydroxybenzaldehyde. Amino groups on chitosan reacts with these aldehydes to form a Schiff base intermediate, which is later on converted into N-alkyl chitosans by reduction with sodium cyanoborohydride. The chemical reaction was monitored by 1H NMR spectroscopy and the absence of aldehydic proton at 9.83ppm in NMR spectra was observed for both the modified chitosan derivatives confirming the reaction. Modified chitosan films were later prepared by solution casting method and their physico-mechanical, barrier, optical and thermal properties were studied. The results clearly indicated significant change in tensile strength, water vapour transmission rate, and haze properties of modified chitosans. Modified chitosan films were also studied for their antimicrobial activity against Aspergillus flavus. The results showed a marked reduction of aflatoxins produced by the fungus in the presence of the N-vanillyl chitosan and 4-hydroxybenzyl chitosan film discs to 98.9% and non-detectable levels, respectively.

Enhanced transmission with tunable Fano-like profile in magnetic nanofluids.

We observe a Fano-like resonance in a magnetically polarizable nanofluid. Under an external magnetic field, the transmittance spectrum of a ferrofluid emulsion containing droplet size of ~220 nm shows an enhanced peak with a Fano-like profile, which is attributed to a localized waveguide resonance from random array of tubes with charged inner surface that are formed by the alignment of the droplets. Furthermore, by varying the magnetic field, the Fano profile is tuned and an opaque emulsion is turned into a transparent one. This finding may have interesting applications in tunable photonic devices.

Intercomparison of gamma scattering, gammatography, and radiography techniques for mild steel nonuniform corrosion detection.

This paper focuses on the mild steel (MS) corrosion detection and intercomparison of results obtained by gamma scattering, gammatography, and radiography techniques. The gamma scattering non-destructive evaluation (NDE) method utilizes scattered gamma radiation for the detection of corrosion, and the scattering experimental setup is an indigenously designed automated personal computer (PC) controlled scanning system consisting of computerized numerical control (CNC) controlled six-axis source detector system and four-axis job positioning system. The system has been successfully used to quantify the magnitude of corrosion and the thickness profile of a MS plate with nonuniform corrosion, and the results are correlated with those obtained from the conventional gammatography and radiography imaging measurements. A simple and straightforward reconstruction algorithm to reconstruct the densities of the objects under investigation and an unambiguous interpretation of the signal as a function of material density at any point of the thick object being inspected is described. In this simple and straightforward method the density of the target need not be known and only the knowledge of the target material's mass attenuation coefficients (composition) for the incident and scattered energies is enough to reconstruct the density of the each voxel of the specimen being studied. The Monte Carlo (MC) numerical simulation of the phenomena is done using the Monte Carlo N-Particle Transport Code (MCNP) and the quantitative estimates of the values of signal-to-noise ratio for different percentages of MS corrosion derived from these simulations are presented and the spectra are compared with the experimental data. The gammatography experiments are carried out using the same PC controlled scanning system in a narrow beam, good geometry setup, and the thickness loss is estimated from the measured transmitted intensity. Radiography of the MS plates is carried out using 160 kV x-ray machine. The digitized radiographs with a resolution of 50 µm are processed for the detection of corrosion damage in five different locations. The thickness losses due to the corrosion of the MS plate obtained by gamma scattering method are compared with those values obtained by gammatography and radiography techniques. The percentage thickness loss estimated at different positions of the corroded MS plate varies from 17.78 to 27.0, from 18.9 to 24.28, and from 18.9 to 24.28 by gamma scattering, gammatography, and radiography techniques, respectively. Overall, these results are consistent and in line with each other.

Changes of skin temperature of parts of the body and serum asymmetric dimethylarginine (ADMA) in type-2 diabetes mellitus Indian patients.

In India, number of people with type 2 Diabetes Mellitus (DM) would be 87 million by the year 2030. DM disturbs autonomic regulation of skin micro-circulation, and causes decrease in resting blood flows through the skin. The skin blood flow has a major effect on its temperature. The aim of the study was to evaluate changes of skin temperature of all parts of the body and serum asymmetric dimethylarginine, ADMA (µmol/L) in type-2 DM Indian patients. Group-I: Normal (n = 17; M/F: 10/15, mean ± SD = 43.2 ± 9.4 years); Group-II: Type-2 DM without cardiovascular (CV) complications (n = 15; M/F: 10/7, mean ± SD = 46.3 ± 14.0 years); Thermograms of all parts of the body were acquired using a non-contact infrared (IR) thermography camera (ThermaCAM T400, FLIR Systems, Sweden). Blood parameters and thyroid hormone were measured biochemically. Indian diabetic risk score (IDRS) was calculated for each subject. In type-2 DM patients without CV group (n = 15), there was a statistically significant (p = 0.01) negative correlations between HbA(1c) and skin temperature of eye and nose (r = -0.57 and r = -0.55 respectively). ADMA was correlated significantly (p = 0.01) with HbA(1c) (r = 0.65) and estimated average glucose, eAG (r = 0.63). In normal subjects, mean minimum and maximum values of skin temperatures were observed at posterior side of sole (26.89 °C) and ear (36.85 °C) respectively. In type-2 DM without CV, mean values of skin temperature in different parts of the body from head to toe were lesser than those values in control group; but this decreases were statistically significant in nose (32.66 Vs 33.99 °C, p = 0.024) as well as in tibia (32.78 Vs 33.13 °C, p = 0.036) regions.

Correlation between plantar foot temperature and diabetic neuropathy: a case study by using an infrared thermal imaging technique.

BACKGROUND: Diabetic neuropathy consists of multiple clinical manifestations of which loss of sensation is most prominent. High temperatures under the foot coupled with reduced or complete loss of sensation can predispose the patient to foot ulceration. The aim of this study was to look at the correlation between plantar foot temperature and diabetic neuropathy using a noninvasive infrared thermal imaging technique. METHODS: Infrared thermal imaging, a remote and noncontact experimental tool, was used to study the plantar foot temperatures of 112 subjects with type 2 diabetes selected from a tertiary diabetes centre in South India. RESULTS: Patients with diabetic neuropathy (defined as vibration perception threshold (VPT) values on biothesiometry greater than 20 V) had a higher foot temperature (32-35 °C) compared to patients without neuropathy (27-30 °C). Diabetic subjects with neuropathy also had higher mean foot temperature (MFT) (p=.001) compared to non-neuropathic subjects. MFT also showed a positive correlation with right great toe (r=0.301, p=.001) and left great toe VPT values (r=0.292, p=.002). However, there was no correlation between glycated hemoglobin and MFT. CONCLUSIONS: Infrared thermal imaging may be used as an additional tool for evaluation of high risk diabetic feet.

Experimental investigation of magnetic-field-induced aggregation kinetics in nonaqueous ferrofluids.

We investigate the influence of field ramp rate on the kinetics of magnetic dipole-dipole induced chainlike structure formation in a nonaqueous nanoparticle dispersion using light scattering studies. With increase in magnetic field, at a constant ramp rate, the transmitted light intensity diminishes and the transmitted light spot is transformed to a diffused ring due to scattering from the self-assembled linear aggregates. The decay rate of transmitted intensity increases up to an optimum ramp rate, above which the trend becomes reverse. At an optimum ramp rate, the minimum time for initial aggregation coincides with the exposure time where the intensity decay is fastest. The variation of transmitted intensity at different ramp rate is explained on the basis of initial aggregation time that depends on Brownian motion, dipolar magnetic attraction and multibody hydrodynamic interactions. The slope of the transmitted light intensity after the removal of magnetic field depends on the time required for dissociation of ordered linear structures. Disappearance of the ring pattern and the reappearance of original light spot, upon removal of the magnetic field, confirm the perfect reversibility of the linear aggregates. The observed concentration dependant decay rates are in good agreement with aggregation theory.

Looped back fiber mode for reduction of false alarm in leak detection using distributed optical fiber sensor.

Optical-fiber-based sensors have inherent advantages, such as immunity to electromagnetic interference, compared to the conventional sensors. Distributed optical fiber sensor (DOFS) systems, such as Raman and Brillouin distributed temperature sensors are used for leak detection. The inherent noise of fiber-based systems leads to occasional false alarms. In this paper, a methodology is proposed to overcome this. This uses a looped back fiber mode in DOFS and voting logic is employed to considerably reduce the false alarm rate.

Single-fiber grid for improved spatial resolution in distributed fiber optic sensor.

The spatial resolution of an optical-fiber-based Raman distributed temperature sensor is limited by the pulse width of the laser used. We discuss a methodology of increasing spatial resolution by using a single-fiber grid. Spatial resolution improvement of up to 10 times is demonstrated.

Implantation induced hardening of nanocrystalline titanium thin films.

Formation of nanocrystalline TiN at low temperatures was demonstrated by combining Pulsed Laser Deposition (PLD) and ion implantation techniques. The Ti films of nominal thickness approximatly 250 nm were deposited at a substrate temperature of 200 degrees C by ablating a high pure titanium target in UHV conditions using a nanosecond pulsed Nd:YAG laser operating at 1064 nm. These films were implanted with 100 keV N+ ions with fluence ranging from 1.0 x 10(16) ions/cm2 to 1.0 x 10(17) ions/cm2 The structural, compositional and morphological evolutions were tracked using Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS) and Atomic Force Microscopy (AFM), respectively. TEM analysis revealed that the as-deposited titanium film is an fcc phase. With increasing ion fluence, its structure becomes amorphous phase before precipitation of nanocrystalline fcc TIN phase. Compositional depth profiles obtained from SIMS have shown the extent of nitrogen concentration gradient in the implantation zone. Both as-deposited and ion implanted films showed much higher hardness as compared to the bulk titanium. AFM studies revealed a gradual increase in surface roughness leading to surface patterning with increase in ion fluence.

Experimental evidence for reversible zippering of chains in magnetic nanofluids under external magnetic fields.

We study the time-dependent transmitted intensity and the scattered pattern from magnetic nanofluids at constant ramping of uniform external magnetic field. The nanofluid used is the dispersion of magnetite particles with an average diameter of 6.5 nm with a protective surfactant coating. We observe several critical fields at which the transmitted light intensity decreases drastically followed by the formation of a ringlike pattern on a screen placed perpendicular to the field direction. Interestingly, the critical fields occur at a regular interval of 20 G. The observed critical fields are attributed to zippering transitions of the chains due to attractive energy well when the chains are of different lengths or shifted with respect to one another. Interaction energy calculations show a decrease in the energy of the system due to dipolar interactions at different critical fields confirming the lowering of the system energy through lateral coalescence. The observed zippering phenomenon is perfectly reversible.

Infrared thermal imaging for detection of peripheral vascular disorders.

Body temperature is a very useful parameter for diagnosing diseases. There is a definite correlation between body temperature and diseases. We have used Infrared Thermography to study noninvasive diagnosis of peripheral vascular diseases. Temperature gradients are observed in the affected regions of patients with vascular disorders, which indicate abnormal blood flow in the affected region. Thermal imaging results are well correlated with the clinical findings. Certain areas on the affected limbs show increased temperature profiles, probably due to inflammation and underlying venous flow changes. In general the temperature contrast in the affected regions is about 0.7 to 1 degrees C above the normal regions, due to sluggish blood circulation. The results suggest that the thermal imaging technique is an effective technique for detecting small temperature changes in the human body due to vascular disorders.

Production and characterization of bacterial polyhydroxyalkanoate copolymers and evaluation of their blends by fourier transform infrared spectroscopy and scanning electron microscopy.

Rhizobium meliloti produced a copolymer of short chain length polyhydroxyalkanoate (scl-PHA) on sucrose and rice bran oil as carbon substrates. Recombinant Escherichia coli (JC7623ABC1J4), bearing PHA synthesis genes, was used to synthesize short chain length-co-medium chain length PHA (scl-co-mcl-PHA) on glucose and decanoic acid. Fourier transform infrared spectroscopy (FTIR) spectra of the PHAs indicated strong characteristic bands at 1282, 1723, and 2934 cm(-1) for scl-PHA and at 2933 and 2976 cm(-1) for scl-co-mcl-PHA polymer. Differentiation of polyhydroxybutyrate (PHB) and polyhydroxybutyrate-co-hydroxyvalerate-P(HB-co-HV) copolymer was obseverd using FTIR, with absorption bands at 1723 and 1281 for PHB, and at 1738, 1134, 1215 cm(-1) for HV-copolymer. The copolymers were analyzed by GC and (1)H NMR spectroscopy. Films of polymer blends of PHA produced by R. meliloti and recombinant E. coli were prepared using glycerol, polyethylene glycol, polyvinyl acetate, individually (1:1 ratio), to modify the mechanical properties of the films and these films were evaluated by FTIR and scanning electron microscopy.

Light scattering in a magnetically polarizable nanoparticle suspension.

We investigate magnetic-field-induced changes on transmitted light intensity in a magnetic disordered phase of iron oxide nanoparticle suspension. We observe a dramatic decrease in the transmitted light intensity at a critical magnetic field. The critical magnetic field follows power-law dependence with the volume fraction of the nanoparticles suggesting a disorder-order structural transition. The light intensity recovers fully when the magnetic field is switched off. We discuss the possible reasons for the reduction in the light intensity under the influence of magnetic field. Among the various mechanisms such as Kerker's condition for zero forward scattering, Faraday effect, Christiansen effect, photoinduced refractive index mismatch between the two components of the dispersion, etc., the resonances within the magnetic scatterers appear to be the plausible cause for the extinction of light. The circular pattern observed on a screen placed perpendicular to the incident beam confirms the formation of rodlike structures along the direction of propagation of the light.

Nondestructive characterization of musical pillars of Mahamandapam of Vitthala Temple at Hampi, India.

This paper presents the first scientific investigation on the musical pillars of the Vitthala Temple at Hampi, India. The solid stone columns in these pillars produce audible sound, when struck with a finger. Systematic investigations on the acoustic characteristics of the musical pillars of mahamandapam (great stage) of the Vitthala Temple have been carried out. The 11 most popular pillars that produce sounds of specific musical instruments are considered for the investigations. The sound produced from these 11 most popular musical pillars was recorded systematically and different nondestructive testing techniques such as low frequency ultrasonic testing, impact echo testing, and in situ metallography were employed on the musical columns of these pillars. The peak frequencies in the amplitude spectrum of the sound produced from various columns in these pillars are correlated with the dimensional measurements and ultrasonic velocity determined using impact echo technique. The peak frequencies obtained experimentally have been found to have excellent correlation with the calculated flexural frequencies based on the dimensional measurements and ultrasonic velocities of the columns.

Ultrasonic properties of nanoparticles-liquid suspensions.

A polymer colloidal solution having dispersed nanoparticles of Cu and Au metals have been developed using a novel chemical method. Average size of the nanoparticles could be varied in the 4-10 nm range by conducting the reaction at an elevated temperature of 50-70 degrees C. Colloidal solutions of representative concentrations of 0.1-2.0 wt% Cu/Au contents in the primary solutions are used to study the modified ultrasonic attenuation and ultrasonic velocity in PVA polymer molecules on incorporating the Cu/Au particles. A characteristic behaviour of the ultrasonic velocity and the attenuation are observed at the particular temperature/particle concentration. The results demonstrate that the primary reaction during the nanoparticles-PVA colloidal formation occurs in divided groups in small micelles. The results are analyzed predicting the enhanced thermal conductivity of the samples.

Evidence for enhanced thermal conduction through percolating structures in nanofluids.

The unusually large enhancement of thermal conductivity (k/k(f)∼4.0, where k and k(f) are the thermal conductivities of the nanofluid and the base fluid, respectively) observed in a nanofluid containing linear chain-like aggregates provides direct evidence for efficient transport of heat through percolating paths. The nanofluid used was a stable colloidal suspension of magnetite (Fe(3)O(4)) nanoparticles of average diameter 6.7 nm, coated with oleic acid and dispersed in kerosene. The maximum enhancement under magnetic field was about 48φ (where φ is the volume fraction). The maximum enhancement is observed when chain-like aggregates are uniformly dispersed without clumping. These results also suggest that nanofluids containing well-dispersed nanoparticles (without aggregates) do not exhibit significant enhancement of thermal conductivity. Our findings offer promising applications for developing a new generation of nanofluids with tunable thermal conductivity.

Mechanism of bright red emission in Si nanoclusters.

A bright photoluminescence around 1.7 eV is observed for post-annealed samples of 1 MeV Si(2+) implanted in an SiO(2) matrix. A super-linear power dependence of photoluminescence intensity accompanied by pulse shortening under continuous wave laser excitation is recorded without any spectral narrowing. An emission process comprised of an initial non-radiative recombination (time constant ∼280-315 ps) of excited carriers in the defect states in SiO(2) matrices to the conduction band minima of nc-Si, followed by a slower process of radiative recombination in the direct band transition for nc-Si along with a non-radiative Auger recombination (time constant ∼2.67 ns) is proposed.

Synthesis and characterization of nanocrystalline Cr2O3 and ZrO2 ceramic materials.

A novel methodology based on a hybrid approach has been evolved for synthesizing nearly monodisperse nanocrystalline oxides. The approach basically involves precipitation of gelatinous hydroxide in liquid phase hydrolysis and subsequent temperature programmed calcination to obtain nanocrystalline oxide. Cr2O3 and ZrO2 have been synthesized through this route. This paper describes synthesis procedures giving details of temperature windows required for this synthesis. In addition, solid state analytical technique like X-Ray Diffraction (XRD) and Photoluminescence (PL) have been used to characterize these materials. Especially PL was used to derive information on confinement effect. Transmission Electron Microscope (TEM), Scanning Probe Microscope (SPM), and Scanning Near Field Optical Microscope (SNOM) were used to derive morphology.

Effect of digestion time and alkali addition rate on physical properties of magnetite nanoparticles.

We investigate the effect of digestion time and alkali addition rate on the size and magnetic properties of precipitated magnetite nanoparticles. It is observed that the time required to complete the growth process for magnetite nanocrystals is very short (approximately 300 s), compared to long digestion times (20-190 min) required for MnO and CdSe nanocrystals. The rapid growth of magnetite nanoparticles suggests that Oswald ripening is insignificant during the precipitation stage, due to the low solubility of the oxides and the domination of a solid-state reaction where high electron mobility between Fe2+ and Fe3+ ions drives a local cubic close-packed ordering. During the growth stage (0-300 s), the increase in the particle size is nominal (6.7-8.2 nm). The effect of alkali addition rate on particle size reveals that the nanocrystal size decreases with increasing alkali addition rate. The particle size decreases from 11 to 6.8 nm as the alkali addition rate is increased from 1 to 80 mL/s. During the size decrease, the lattice parameter decreases from 0.838 to 0.835 nm, which is attributed to an increase in the amount of Fe3+ atoms at the surface due to oxidation. As the alkali addition rate increases, the solution reaches supersaturation state rapidly leading to the formation of large number of initial nuclei at the nucleation stage, resulting in large number of particles with smaller size. When alkali addition rate is increased from 1 to 80 mL/s, the saturation magnetization of the particles decreases from 60 to 46 emu/g due to the reduced particle size.