New Hyperspectral Procedure to Discriminate Intertidal Macroalgae

The recent development and miniaturization of hyperspectral sensors embedded in drones has allowed the acquisition of hyperspectral images with high spectral and spatial resolution. The characteristics of both the embedded sensors and drones (viewing angle, flying altitude, resolution) create opportunities to consider the use of hyperspectral imagery to map and monitor macroalgae communities. In general, the overflight of the areas to be mapped is conconmittently associated accompanied with measurements carried out in the field to acquire the spectra of previously identified objects. An alternative to these simultaneous acquisitions is to use a hyperspectral library made up of pure spectra of the different species in place, that would spare field acquisition of spectra during each flight. However, the use of such a technique requires developed appropriate procedure for testing the level of species classification that can be achieved, as well as the reproducibility of the classification over time. This study presents a novel classification approach based on the use of reflectance spectra of macroalgae acquired in controlled conditions. This overall approach developed is based on both the use of the spectral angle mapper (SAM) algorithm applied on first derivative hyperspectral data. The efficiency of this approach has been tested on a hyperspectral library composed of 16 macroalgae species, and its temporal reproducibility has been tested on a monthly survey of the spectral response of different macro-algae species. In addition, the classification results obtained with this new approach were also compared to the results obtained through the use of the most recent and robust procedure published. The classification obtained shows that the developed approach allows to perfectly discriminate the different phyla, whatever the period. At the species level, the classification approach is less effective when the individuals studied belong to phylogenetically close species (i.e., Fucus spiralis and Fucus serratus).

The Development of Log Aesthetic Patch and Its Projection onto the Plane

In this work, we introduce a new type of surface called the Log Aesthetic Patch (LAP). This surface is an extension of the Coons surface patch, in which the four boundary curves are either planar or spatial Log Aesthetic Curves (LACs). To identify its versatility, we approximated the hyperbolic paraboloid to LAP using the information of lines of curvature (LoC). The outer part of the LoCs, which play a role as the boundary of the hyperbolic paraboloid, is replaced with LACs before constructing the LAP. Since LoCs are essential in shipbuilding for hot and cold bending processes, we investigated the LAP in terms of the LoC’s curvature, derivative of curvature, torsion, and Logarithmic Curvature Graph (LCG). The numerical results indicate that the LoCs for both surfaces possess monotonic curvatures. An advantage of LAP approximation over its original hyperbolic paraboloid is that the LoCs of LAP can be approximated to LACs, and hence the first derivative of curvatures for LoCs are monotonic, whereas they are non-monotonic for the hyperbolic paraboloid. This confirms that the LAP produced is indeed of high quality. Lastly, we project the LAP onto a plane using geodesic curvature to create strips that can be pasted together, mimicking hot and cold bending processes in the shipbuilding industry.

Monitoring of cyanobacteria using derivative spectrophotometry and improvement of the method detection limit by changing pathlength

Effective monitoring tools and methods are needed for the early detection and management of cyanobacteria in water bodies to minimize their harmful impacts on the environment and public health. This research investigated changing the cuvette pathlength (10-, 50-, and 100-mm) to improve the detection of cyanobacteria using UV-Vis spectrophotometry with subsequent application of derivative spectrophotometry and Savitzky-Golay (S-G) transformation. A non-toxigenic strain of blue-green cyanobacteria, Microcystis aeruginosa (CPCC 632), and a green algae strain for comparison, Chlorella vulgaris (CPCC 90), were studied in a wide range of concentrations (955,000–1,855 cells/mL). In each concentration range, method detection limits were established with absorbance measurements and S-G first derivative of absorbance using 10-, 50-, and 100-mm cuvette pathlengths. Increasing the cuvette pathlength from 10 to 100 mm resulted in a 15-fold improvement in sensitivity with absorbance and a 13-fold improvement with S-G first derivative of absorbance for M. aeruginosa. Overall, adoption of 100 mm pathlength and application of S-G derivative spectra improved the method detection limit for M. aeruginosa from 337,398 cells/mL to 4,916 cells/mL, which is below the WHO guideline for low probability of adverse health effects (<20,000 cells/mL). Similarly, the detection limit for C. vulgaris was improved from 650,414 cells/mL to 11,661 cells/mL. The results also showed that spectrophotometry could differentiate M. aeruginosa from C. vulgaris based on the variations in their pigment absorbance peaks.

Superfield approach to interacting N = 2 massive and massless supermultiplets in 3d flat space

Massive arbitrary spin supermultiplets and massless (scalar and spin one-half) supermultiplets of the N = 2 Poincaré superalgebra in three-dimensional flat space are considered. Both the integer spin and half-integer spin supermultiplets are studied. For such massive and massless supermultiplets, a formulation in terms of light-cone gauge unconstrained superfields defined in a momentum superspace is developed. For the supermultiplets under consideration a superspace first derivative representation for all cubic interaction vertices is obtained. A superspace representation for dynamical generators of the N = 2 Poincaré superalgebra is also found.

Prognostic Features of Near-Infrared Spectroscopy Following Primary Radical Prostatectomy

Background: Only a few biomarkers have been evaluated for their prognostic value with regard to biochemical recurrence (BCR) following primary radical prostatectomy. We explored the possibilities of using near-infrared (NIR) spectroscopy as a prognostic biomarker for BCR-free survival (BCR-FS). Methods: Tissue specimens from 82 prostate cancer patients were obtained. Formalin-fixed paraffin-embedded slides (hematoxylin–eosin-stained) were analyzed using NIR spectroscopy. Prognostic features for BCR-FS were determined following normalization of the spectra. Results: Several differences were found throughout the NIR spectrum for the patients with or without BCR, for both the first derivative and second derivative of the NIR spectrum. Following categorization and Cox regression analysis, spectral regions at 5236 cm−1 (first derivative; median BCR-FS not reached versus 3.2 years; HRhigh = 0.18 [0.08–0.39]; and p < 0.0001) and at 5956 cm−1 (second derivative; median BCR-FS not reached versus 3.8 years; HRlow = 0.22 [0.10–0.48]; and p = 0.0002) showed prognostic properties for BCR-FS. The combination of both parameters further increased the prognostic value of NIR (p < 0.0001). Conclusions: We demonstrated NIR spectral variations between patients with or without BCR, which have been shown to have prognostic value. This easy-to-use technique could possibly further improve post-primary radical prostatectomy monitoring and swift referral to adjuvant local therapies. Further elaboration is highly recommended to fully elucidate these variations and to gain a deeper insight into the changing chemical and physical compositions of the prostate tumor architecture.

Validation of UV Spectrophotometry Method for Determination of Lopinavir and Ritonavir Simultaneously

Lopinavir and ritonavir are anti-viral compounds that have similar chemical structures and overlapping UV spectral profiles. The combination of these two compounds is being promoted as an anti-COVID19 drug. Determination of these two compounds simultaneously using UV spectrophotometry method requires special technique so that the result will be valid. The purpose of this study was to obtain a suitable analytical technique using UV spectrophotometry for the determination of lopinavir-ritonavir simultaneously that fulfill the method validation requirement. In this study, the simultaneous equation technique, absorptivity comparison factor, and first derivative technique were used to overcome the effect of lopinavir/ritonavir absorbance at selected wavelengths for determination of each compound simultaneously. The one-way ANOVA statistical test was used to compare the result of the three analytical techniques. The results showed that the three techniques fullfilled the AOAC requirements for selectivity and linearity. The accuracy and precision test result have not met the requirements of the AOAC method validation. Statistically. the one-way ANOVA analysis showed there was a significant difference between the mean recovery of lopinavir using the absorptivity factor and first derivative technique. Whereas, there was no significant differences among the mean of ritonavir recoveries that were determined using those three techniques. As conclusion, that the UV spectrophotometric method using the simultaneous equation technique, the absorptivity factor technique, and the derivative technique for assaying the lopinavir and ritonavir simultaneously met the requirements for selectivity and linearity parameters. However, the accuracy and precision have not met the requirements. The first derivative technique is suitable for further developed for ritonavir and lopinavir determination simultaneously

Method Development and Validation for the Estimation of Etizolam and Propranolol Hydrochloride in bulk and Combined Dosage Forms by Simultaneous and Derivative Spectroscopic Methods

Accurate, simple, sensitive and rapid economic UV spectroscopic methods were developed for the estimation of Etizolam and Propranolol Hydrochloride in bulk and combined dosage form. The present study deals with the UV spectroscopic method development and validation for the Simultaneous Equation method and First Derivative method of Etizolam and Propranolol Hydrochloride in bulk and combined dosage form at determined wavelength of Etizolam and Propranolol Hydrochloride at 244nm and 288nm for Simultaneous Equation method and 234nm and 289nm for First Derivative Method. The linearity range for Etizolam and Propranolol Hydrochloride was 1-5µg/ml and 10-50µg/ml, and exhibit good correlation coefficient of Etizolam and Propranolol Hydrochloride was 0.9877 and 0.9977 for Simultaneous Equation method and 0.9872 and 0.9977 for First Derivative method, respectively and excellent mean recovery (98-102%). The precision was found to be within limit (%RSD <2). Comparatively First Derivative method is more sensitive than Simultaneous Equation method. The methods were validated statistically and parameters like linearity, precision, accuracy, specificity and assay was studied according to ICH guidelines and can be applicable in determination of both drugs in routine quality control analysis of drugs in bulk and combined dosage form.