Orientational dependence of the IR absorbing amide bands of silk is demonstrated from two orthogonal longitudinal and transverse microtome slices only $\sim 100$~nm thick. A scanning near-field optical microscopy (SNOM) which preferentially probes orientation perpendicular to the sample's surface was used. Spatial resolution of silk-epoxy boundary was defined with a $\sim 100$~nm resolution while the spectra were collected by a $\sim 10$~nm tip. Ratio of the absorbance of the amide-II C-N at 1512~cm$^{-1}$ and amide-I C=O $\beta$-sheets at 1628~cm$^{-1}$ showed sensitivity of SNOM to the molecular orientation. SNOM characterisation is complimentary to the far-field absorbance which is sensitive to the in-plane polarisation. Volumes with cross sections smaller than 100~nm can be characterised for molecular orientation. A method of absorbance measurements at four angles of slice cut orientation, which is equivalent to the four polarisation angles absorbance measurement is proposed.

There are different ways to analyse energy absorbance (EA) in the human auditory system. In previous research, we developed a complete finite element model (FEM) of the human auditory system. In this mentioned work, the external auditory canal (EAC), middle ear, and inner ear (spiral cochlea, vestibule, and semi-circular canals) were modelled based on human temporal bone histological sections. Multiple acoustic, structure and fluid-coupled analyses were conducted using the FEM to perform harmonic analyses in the 0.1–10 kHz range. Once the FEM had been validated with published experimental data, the FEM numerical results were used to calculate the EA or energy reflected (ER) by the tympanic membrane. This EA was also measured in clinical audiology tests which were used as a diagnostic parameter. A mathematical approach was developed to calculate the EA and ER, with numerical and experimental results showing adequate correlation up to 1 kHz. Another published FEM had adapted its boundary conditions to replicate experimental results. Here, we recalculated those numerical results by applying the natural boundary conditions of human hearing and found that the results almost totally agreed with our FEM. This boundary problem is frequent and problematic in experimental hearing test protocols: the more invasive they are, the more the results are affected. One of the main objectives of using FEMs is to explore how the experimental test conditions influence the results. Further work will still be required to uncover the relationship between the middle ear structure and EA to clarify how to best use FEMs. Moreover, the FEM boundary conditions must be more representative in future work to ensure their adequate interpretation.

High purity TiO2 and CuO powders were synthesized by the Pechini method, an inexpensive and easy-to-implement procedure to synthetize metal oxides. The variables of synthesis were the ethylene glycol:citric acid molar ratio and the pH. High reproducibility of the anatase and tenorite phase was obtained for all synthesis routes. The degree of purity of the powders was confirmed by XRD, FTIR, UV-vis absorption and XPS spectra. SEM and TEM images revealed the powders are composed by micrometer grains that can have a spherical shape (only in the TiO2) or formed by a non-compacted nanocrystalline conglomerate. FTIR spectra only vibrational modes associated to the TiO2 or CuO with a nanoparticle behavior. UV-vis absorption spectra revealed the values of maximum absorbance percentage of both systems are reached in the ultraviolet region, with percentages above 83 % throughout the entire visible light spectrum for the CuO system, a relevant result for solar cell applications. Finally, XPS experiments allow the observation of the valence bands and the calculation of the energy bands of all oxides.

Tomato (Solanum lycopersicum), an important vegetable crop, is a host for numerous pests and pathogens. Consequently, tomato breeders are striving to improve pest resistance. Many acces-sions of the wild relative S. habrochaites display high resistance towards arthropod pests such as spider mites and whiteflies and the presence of the sesquiterpene hydrocarbon 7-epi zingiberene in its trichomes has been associated with arthropod resistance. Consequently, tomato breeders are attempting to introgress 7-epi zingiberene from wild to cultivated tomato, which requires the ability to quantify zingiberene. 7-Epi zingiberene has conjugated double bonds causing it to ab-sorb uv light. In fact, de Freitas, et al. [1] have claimed that measurement of absorbance at 270 nm of tomato leaflet washes can be used to quantify zingiberene. However, this claim has never been critically evaluated. We initially evaluated the use of uv absorbance to estimate zingiberene content of leaflet washes from an interspecific hybrid tomato BC4F2 generation that was segre-gating widely for presence and abundance of zingiberene. When absorbances at 270 nm were compared with zingiberene measured by gas chromatography the resulting relationship did not obey the Beer-Lambert law. Consequently, we examined in detail aspects of the uv-absorbance of zingiberenoids by: 1) obtaining uv absorbance spectra for three isolated zingiberenoids and de-termining the relationship between the abundance of each isolated compound and absorbance at single wavelengths; 2) obtaining uv absorbance spectra of leaflet washes of relevant wild acces-sions and parents; 3) obtaining average absorbance spectra for interspecific generations of tomato that were segregating for abundance of zingiberenoids and determining their λmax values in the 250-280 nm region; 4) evaluating by regression the relationship between absorbance at a single wavelength and the concentration of zingiberene and when present, its derivatives, as measured by gas chromatography in several interspecific hybrid generations; and 5) exploring the potential use of absorbances at multiple wavelengths to improve estimates of concentrations of zingi-berenoids. Results indicated that isolated zingiberenoids as well as leaflet washes of wild tomatoes that contain zingiberenoids have broad absorbance spectra in the uv region with a λmax of 264 nm. The relationship between abundance of isolated zingiberenoids and absorbance at a single wavelength of 264 nm did obey the Beer-Lambert Law. Average absorbance spectra for leaflet washes from BC3F5 generation plants sampled by two methods, as well as from a BC5F1 and a BC3F3 generation showed subtle shifts in the λmax away from 264 nm. Furthermore, the rela-tionship between absorbance at 264 nm and zingiberenoid content of these generations did not obey the Beer-Lambert Law in that in each case regression of absorbance on zingiberenoid content of the leaflet washes resulted in non-zero intercept estimates that varied considerably among generations and sampling methods. Use of multiple wavelengths for estimation zingiberenoids in these breeding generations was explored and inclusion of additional absorbances at one or two wavelengths identified by stepwise regression always improved estimates of zingiberenoid content from absorbance data. However, the identified wavelength(s) differed among generations. Taken together the results indicate that measurement of absorbance of tomato leaflet washes at a single wavelength is not a reliable quantitative estimate of zingiberenoids in the leaflet wash. These estimates can be improved by utilizing absorbance at multiple wavelengths, but the par-ticular wavelengths will likely vary among generations. Lastly, measurement of absorbance may be a useful tool in identifying those relatively rare individuals in a generation that is widely segregating for zingiberenoid content. However, even in this situation the determination of the actual zingiberene content e.g., for comparison with the donor parent, would need to be back-stopped by a valid quantitative method such as gas chromatography.

Optical “fingerprints” are widely used in chemometrics-assited recognition of samples of different nature. An emerging trend in this area is the transition from obtaining "static" spectral data to reactions occurring over time. The indicator reactions are usually carried out in aqueous solutions; in this study we have developed the reactions that occur in an organic solvent, which makes it possible to recognize fat-soluble samples. In this capacity, we used 5W40, 10W40 and 5W30 motor oils of 4 manufacturers, totally 6 samples. The procedure involved mixing of the dye, sample, and reagents (HNO3, HCl, or t-butyl hydroperoxide) in ethanolic solution in a 96-well plate and measuring absorbance or near-IR fluorescence intensity every several minutes during 20–55 min. The obtained photographic images were processed by linear discriminant analysis (LDA) and k-nearest neighbors algorithm (kNN). The discrimination accuracy was evaluated by using the validation procedure. Reaction of oxidation of a dye with nitric acid allowed to recognize all 6 samples with 100% accuracy by LDA. Merging data of 4 reactions that did not provide complete discrimination ensured an accuracy of 93% by kNN technique. The developed indicator systems have good prospects for the discrimination of other fat-soluble samples. Overall, the results confirm the viability of the kinetic-based discrimination strategy.

In this article, two elliptical-ovel-shaped cylindrical dielectric resonator based wideband Graphene inspired reconfigurable metasurface absorber is designed on diffused quartz substrate having a relative permittivity of 3.75 and conductivity 2200Kg/m3 with height of 25μm. This metasurface having gold plated ground in microstrip with 5μm which is essential by calculating skin depth at 2.0THz frequency. Two elliptical ovel shaped patches with Graphene plated having built in potential varies 0-2.5eV and relaxation time 1.0ps at 290oK. By changing the relaxation time of Graphene 0.1ps-0.3ps its resonance frequency also varies i.e., reconfigurable property they provide without adding any active i.e., PIN diode components. The proposed MS is designed having a dimension of 100×100μm2 is designed on a microstrip. This MS works in the range of 1.6-2.38THz having more than 90% absorbance with two transmission zero at 2.1THz and 2.3THz having high Q ˃ 50 which is used to determine the sensitivity where the proposed MS used as a sensor to determine hemoglobin (Blood Glucose level) and urine (Uric acid) by changing their refractive index from 1.34-1.43. Maximum sensitivity achieved at 2000GHz/RIU and average sensitivity for hemoglobin and urine sensing achieved 833.33GHz/RIU, FOM-8.33 and 4277.7733GHz/RIU, FOM-555.55 respectively.