Analytical Chemistry

Energy consumption constraints on computing systems are more important than ever. Maintenance costs for high performance systems are limiting the applicability of processing devices with large dissipation power. New solutions are needed to increase both the computation capability and the power efficiency. Moreover, energy efficient applications should balance performance vs. consumption. Therefore power data of components are important. This work presents the most remarkable alternatives to measure the power consumption of different types of computing systems, describing the advantages and limitations of available power measurement systems. Finally, a methodology is proposed to select the right power consumption measurement system taking into account precision of the measure, scalability and controllability of the acquisition system.

 The binding interaction between clofarabine and human serum albumin (HSA) and alpha 1 acid glycoprotein (AAG) was investigated.  Clofarabine caused fluorescence quenching of both HSA and AAG by static mode  UV-visible spectroscopy deciphered the formation of ground state complex between clofarabine and the two studied proteins.  There is stronger interaction of clofarabine with AAG as compared to HSA.  The Gibbs free energy change was found to be negative for the interaction of clofarabine with AAG and HSA indicating the binding process is spontaneous.  Binding of clofarabine with HSA and AAG induced ordered structures in both proteins and leads to molecular compaction.  Hydrogen bonding and hydrophobic interactions are the main bonding forces between HSA-clofarabine and AAG-clofarabine as revealed by docking results.

The characterization of novel metal reinforced electro-dialysis ion exchange membranes, for water desalination, by attenuated total reflectance Fourier Transform infra-red spectroscopy mapping is presented in this paper. The surface of the porous stainless steel fibre meshes was treated in order to enhance the amount of surface oxide groups and increase the material hydrophilicity. Then, the metal membranes were functionalized through a sol-gel reaction with silane coupling agents to enhance the affinity with the ion exchange resins and avoid premature metal oxidation due to redox reactions at the metalpolymer interface. Polished cross sections of the composite membranes embedded into an epoxy resin revealed interfaces between metallic frameworks and the silane layer at the interface with the ion exchange material. The morphology of the metalpolymer interface was investigated with scanning electron microscopy and Fourier transform infra-red micro-spectroscopy. Fourier transform infra-red mapping of the interfaces was performed using the attenuated total reflectance mode on the polished cross-sections at the Australian Synchrotron. The nature of the interface between the metal framework and the ion exchange resin was shown to be homogeneous and the coating thickness was found to be around 1 μm determined by Fourier transform infra-red micro-spectroscopy mapping. The impact of the coating on the properties of the membranes and their potential for water desalination by electro-dialysis are also discussed.

Infrared polarized microspectra of transverse leaf sections of Sorghum bicolor show significant anisotropy of vibrational modes. They reveal the preferential orientation of the sub-micron cellulose fibrils and other biopolymers in single cell walls.

Total ion concentrations of sodium, potassium, calcium and chloride have been measured reversibly by ion-selective optode membranes with comparable selectivity to potentiometric systems. The results of quality-control samples analysed by the selective optode membranes show a good agreement with the assigned values and a reasonable reproducibility, though for quantification of sodium and potassium the unknown concentrations are evaluated in a first trial by a standard addition method. All measurements are referred to a pair of blank membranes in a reference cell to compensate for interferences induced by the diluted plasma sample. The efficiency of the evaluated values with regard to the medical interpretation encompasses the performance standard of the analytical procedure as well as the intra-and interindividual variation of the subjects studied. The required performance characteristics of a sensor are constituted dilhzrently, depending on the mode of application and the medical question to be answered. The type of optodes described may be tailored to a large extent to adapt them to the required performance boundary conditions. This will bc discussed with respect to other optical sensor schemes.

The properties of optode membranes to be used for realizing miniature integrated optical sensors based on refractometry have been investigated theoretically and experimentally. In situ referencing by using optode and reference membranes on the same chip is a powerful means to discriminate against unspecific effects. The plasticized polymer membranes provide the function of selective extraction and chemical recognition of the analyte. In experiments performed for a pair of such membranes, refractive index differences ~3 x 10 3 per decade of molar Ca 2+ concentration in buffered aqueous solutions have been observed. With the characterized type of sensing pad implanted in a miniature integrated optical device, a typical overall resolution of 0.7 to 0.07% in units of Ca 2~ concentration was calculated.

The tanning industry is the major chromium consuming industry. Tanning industries are present throughout Pakistan, but their presence is more concentrated in small industrial city Sialkot. The samples of wastewater were collected from different tanneries and Nullah Aik which are situated in Sialkot and analyzed for the measurement of pollution level. The effluents sample demonstrated high values of temperature (32-42°C), pH (5.1-10.9), biological oxygen demand (335-5818 mg/L), chemical oxygen demand (740-14546 mg/L), total solids (2265-19314 mg/L), total dissolved solids (1313-17467 mg/L), hexavalent chromium (1.8-9.8 mg/L), and total chromium (3.75-16.7 mg/L). The total chromium analyzed by atomic absorption spectrometry and hexavalent chromium determined by UV-Visible Spectrophotometer with DCP. The study focused on the level of pollution in tannery wastewater to estimate the impairment caused by them.    

log P values of 14 biologically active (E)-3-(X-benzylidene)-2,3-dihydro-1-benzopyran-4-ones (3) have been determined by an optimized and validated reversed-phase thin-layer chromatography (RP-TLC) method. The RP-TLC investigations were performed on silanized silica gel 60F 254 as stationary phase with methanol-water 60:40 (v/v) as mobile phase. The RP-TLC method was validated by analysis of four drugs, diazepam, progesterone, PGE 1 ethyl ester, and itraconazole, with known log P SF (shake-flask) values. The experimentally determined log P TLC values were compared with the predicted log P values obtained by the CLOGP program. The log P TLC values of the investigated (E)-3-(X-benzylidene)-2,3-dihydro-1benzopyran-4-ones (3) were compared with those of the previously investigated structurally related chalcones (1) and (E)-2-(X-benzylidene)-1-tetralones (2). It was found that the log P TLC values of the respective 4′ ′-X-benzylidene analogues increased in the 1 < 3 < 2 order. The average difference between the log P TLC data of the respective cyclic 4′-X-benzylidene derivatives 2 and 3 was found to be 0.23 log P unit. The effect of the position (ortho, meta, or para) of the aromatic substituents did not follow regularity in either of the two series. The results indicate the importance of both steric and electronic factors in the lipophilicity of the investigated compounds.

In vivo absorption and oxidative metabolism of salicylic acid in rat small intestine was studied by luminal perfusion experiment. Perfusion through the lumen of proximal jejunum with isotonic medium containing 250 µM sodium salicylate was carried out. Absorption of salicylate was measured by a validated HPLC-DAD method which was evaluated for a number of validation characteristics (specificity, repeatability and intermediate precision, limit of detection, limit of quantification, linearity and accuracy). The method was linear over the concentration range 0.5-50 µg/mL. After liquid-liquid extraction of the perfusion samples oxidative biotransformation of salicylate was also investigated by HPLC-MS. The method was linear over the concentration range 0.25-5.0 µg/mL. Two hydroxylated metabolites of salicylic acid (2,5-dihydroxybenzoic acid and 2,3-dihydroxybenzoic acid) were detected and identified. The mean recovery of extraction was 72.4% for 2,3-DHB, 72.5% for 2,5-DHB and 50.1% for salicylic acid, respectively. The methods were successfully applied to investigate jejunal absorption and oxidative metabolism of sodium salicylate in experimental animals. The methods provide analytical background for further metabolic studies of salycilates under modified physiological conditions.

The objective of this project is to characterize significant chemical degradation pathways of organic chemicals in stored high-level waste and waste treatment streams. The underlying chemistries of high-level waste are 1) the chemistry initiated by radioactive decay and the reactions initiated by heat from radioactive decay and 2) the chemistry resulting from waste management, and treatment activities (e.g., waste transfers, concentration through evaporators, caustic and other chemical additions, and separations operations). Recognizing that experiments cannot reproduce every conceivable scenario, the project works to develop predictive computational models of these chemistries. The effort is closely coordinated with a Notre Dame Radiation Laboratory project (EMSP No. 73832, "The NOx System in Nuclear Waste," D. Meisel, Principal Investigator) that focuses on radiolytically-induced degradation of organic complexants in waste simulants. Investigators combine experimental observations, electronic structure computations, and theoretical methods development to achieve this goal. The resulting models will facilitate accurate evaluation of the hazardous material generated, including flammable gases, and will support decision-making processes regarding safety, retrieval, treatment, and tank closure issues.

A fully automated, continuous-flow-through type analyzer was developed to observe rapid changes in the concentration of total inorganic carbon (CT) in coastal zones. Seawater and an H3PO4 solution were fed into the analyzer's mixing coil by two high-precision valveless piston pumps. The CO2 was stripped from the seawater and moved into a carrier gas, using a newly developed continuous-flow-through CO2 extractor. A mass flow controller was used to assure a precise flow rate of the carrier gas. The CO2 concentration was then determined with a nondispersive infrared gas analyzer. This analyzer achieved a time-resolution of as good as 1 min. In field experiments on a shallow reef flat of Shiraho (Ishigaki Island, Southwest Japan), the analyzer detected short-term, yet extreme, variations in CT which manual sampling missed. Analytical values obtained by the analyzer on the boat were compared with those determined by potentiometric titration with a closed cell in a laboratory: CT(flow-through) = 0.980•CT(titration) + 38.8 with r 2 = 0.995 (n = 34; September 1998).

A fully automated, continuous-flow-through type analyzer was developed to observe rapid changes in the concentration of total inorganic carbon (CT) in coastal zones. Seawater and an H3PO4 solution were fed into the analyzer's mixing coil by two high-precision valveless piston pumps. The CO2 was stripped from the seawater and moved into a carrier gas, using a newly developed continuous-flow-through CO2 extractor. A mass flow controller was used to assure a precise flow rate of the carrier gas. The CO2 concentration was then determined with a nondispersive infrared gas analyzer. This analyzer achieved a time-resolution of as good as 1 min. In field experiments on a shallow reef flat of Shiraho (Ishigaki Island, Southwest Japan), the analyzer detected short-term, yet extreme, variations in CT which manual sampling missed. Analytical values obtained by the analyzer on the boat were compared with those determined by potentiometric titration with a closed cell in a laboratory: CT(flow-through) = 0.980•CT(titration) + 38.8 with r 2 = 0.995 (n = 34; September 1998).

Vicia faba (Fabaceae) is a popular food in many countries and a good source of nutrients. However, little is known about its phytochemical composition, specially referring to phenolic compounds. In the present work, the dietary metabolites from a hydro-methanolic extract of V. faba seeds were thoroughly characterized by a nontargeted analytical approach based on reversed-phase ultra-HPLC (UHPLC) coupled to QTOF-MS. A total of 155 primary and secondary metabolites of various structural types were characterized: carbohydrates, amino acids, organic acids, alkaloids, terpenoids, jasmonates, and, mainly, polyphenols. Among the latter group, 73 compounds were characterized for the first time in this legume. In addition, 24 new structures, belonging to jasmonates and glycosylated N-containing compounds, were also proposed. Thus, this methodology could be implemented in foodomics as a characterization strategy to complement the knowledge of the phytochemical composition of vegetables.

This study describes the development of an analytical methodology based on the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C4D) for the separation and detection of inorganic anions in post‐blast explosive residues. The best separation condition was achieved using a running buffer composed of 35 mmol/L lactic acid, 10 mmol/L histidine and 0.070 mmol/L cetyl(trimethyl ammonium) bromide. For C4D measurements, the highest sensitivity was obtained applying a 700 kHz sinusoidal wave with excitation voltage of 20 Vpp. The separation of Cl−, NO3−, NO2−, SO42−, ClO4− and ClO3− was performed within ca. 150 s with baseline resolution and efficiencies between 4.4 × 104 and 1.7 × 105 plates/m. The found limits of detection ranged between 2.5 and 9.5 μmol/L. Last, real samples of post‐blast explosive residues were analyzed on the ME‐C4D devices obtaining successfully the determination of Cl−, NO3− and SO42−. The achieved c...

In this work, Raman hyperspectral imaging, in conjunction with independent component analysis, was employed as an analytical methodology to detect an ammonium nitrate fuel oil (ANFO) explosive in banknotes after an ATM explosion experiment. The proposed methodology allows for the identification of the ANFO explosive without sample preparation or destroying the sample, at quantities as small as 70μgcm(-2). The explosive was identified following ICA data decomposition by the characteristic nitrate band at 1044cm(-1). The use of Raman hyperspectral imaging and independent component analysis shows great potential for identifying forensic samples by providing chemical and spatial information.

The aim of this study was to develop a methodology using Raman hyperspectral imaging and chemometric methods for identification of pre-and post-blast explosive residues on banknote surfaces. The explosives studied were of military, commercial and propellant uses. After the acquisition of the hyperspectral imaging, independent component analysis (ICA) was applied to extract the pure spectra and the distribution of the corresponding image constituents. The performance of the methodology was evaluated by the explained variance and the lack of fit of the models, by comparing the ICA recovered spectra with the reference spectra using correlation coefficients and by the presence of rotational ambiguity in the ICA solutions. The methodology was applied to forensic samples to solve an automated teller machine explosion case. Independent component analysis proved to be a suitable method of resolving curves, achieving equivalent performance with the multivariate curve resolution with alternating least squares (MCR-ALS) method. At low concentrations, MCR-ALS presents some limitations, as it did not provide the correct solution. The detection limit of the methodology presented in this study was 50 mg cm À2 .

This report describes for the first time the use of microchip electrophoresis (ME) devices integrated with capacitively coupled contactless conductivity detection (C4D) to investigate the authenticity of seized whiskey samples, which were probably adulterated by simple dilution with tap water. The proposed microfluidic platform was explored for the monitoring of anionic species (Cl− and F−) in both original and tampered samples. The best separations were achieved within 70 s using a running buffer composed of lactic acid and histidine (pH = 5.9). ME‐C4D devices were used to analyze samples from three different brands (five samples each). Based on the presence of inorganic anions like Cl−, F−, SO42− and NO2− in different amounts, the authenticity of seized whiskeys was compared to original samples. According to the reported data, the proposed microfluidic platform can be useful to help regulatory authorities in the investigation and monitoring of authenticity of commercialized whiske...

The sequential injection (SIA) technique was applied for the on-line preparation of an "oil in water" microemulsion and for the determination of aluminum in new and used lubricating oils by electrothermal atomic absorption spectrometry (ET AAS) with Zeeman-effect background correction. Respectively, 1.0, 0.5 and 1.0 ml of surfactants mixture, sample and co-surfactant (sec-butanol) solutions were sequentially aspirated to a holding coil. The sonication and repetitive change of the flowing direction improved the stability of the different emulsion types (oil in water, water in oil and microemulsion). The emulsified zone was pumped to fill the sampling arm of the spectrometer with a sub-sample of 200 l. Then, 10 l of this sample solution were introduced by means of air displacement in the graphite tube atomizer. This sequence was timed to synchronize with the previous introduction of 15 g of Mg(NO 3 ) 2 (in a 10 l) by the spectrometer autosampler. The entire SIA system was controlled by a computer, independent of the spectrometer. The furnace program was carried out by employing a heating cycle in four steps: drying (two steps at 110 and 130 • C), pyrolisis (at 1500 • C), atomization (at 2400 • C) and cleaning (at 2400 • C). The calibration graph was linear from 7.7 to 120 g Al l -1 . The characteristic mass (mo) was 33.2 pg/0.0044 s and the detection limit was 2.3 g Al l -1 . The relative standard (RSD) of the method, evaluated by replicate analyses of different lubricating oil samples varied in all cases between 1.5 and 1.7%, and the recovery values found in the analysis of spiked samples ranged from 97.2 to 100.4%. The agreement between the observed and reference values obtained from two NIST Standard Certified Materials was good. The method was simple and satisfactory for determining aluminum in new and used lubricating oils.

The first version of the Brazilian Food Composition Table (TBCA) website was created in 1998. Version 6.0, launched in 2017, was developed collaboratively by the Food Research Center, University of São Paulo and the Brazilian Network of Food Data Systems. It is freely available at www.fcf.usp.br/tbca. The updated version comprises two databases: (i) the Biodiversity and Regional Food Database (TBCA B-DB), which contains analytical data on Brazilian food biodiversity; and (ii) the Nutrient Intake Evaluation Database (TBCA NIE-DB), comprising data on most foods consumed in Brazil, including the content of 34 components. The TBCA NIE-DB presents composition data for more than 3400 foods, including raw foods, manufactured products and composite dishes. The data can be searched by food name in Portuguese or English or by the scientific name. Searches by food group or by component can also be performed, and reports are generated according to the data available and database accessed. A new functionality implemented in the website is the evaluation of energy intake for general users. TBCA NIE-DB is a tool for evaluating nutrient intake for individuals and populations and it assists professionals with dietary prescriptions. Computational tools using TBCA NIE-DB can be developed for various applications, such as generating personalized menus.

The Brazilian Food Composition Table 's Nutrient Intake Evaluation Database (TBCA NIE-DB) was created under the coordination of the Brazilian Network of Food Data Systems/University of São Paulo and the Food Research Center (FoRC). The TBCA NIE-DB is intended as a tool for nutritional intake assessment in Brazil. The data collected during the previous years, following the guidelines of the FAO/INFOODS, formed the basis for the TBCA NIE-DB's elaboration, which prioritized analytical data on Brazilian foods. The elaboration steps included aggregating food with similar descriptions, filling in missing data, collecting recipes for composite dishes and calculating nutrient profiles by applying appropriate yield and nutrient retention factors, and developing the database. Currently, the database comprises data for 3437 food entries, including raw foods, manufactured products, and composite dishes, with 111,027 nutrient values for proximate composition, fat fractions, 10 minerals, and 10 vitamins (34 components). The TBCA NIE-DB is available online for free (www.fcf.usp.br/tbca). Because of its standardization criteria, this database contains nutrient data comparable across countries. Thus, it is a feasible supporting tool for dietary assessment tools, such as the National Dietary Survey of the Brazilian Institute of Geography and Statistics (NDS/IBGE), and the recently adapted Brazilian version of the GloboDiet software.

Fortification of wheat and corn flours with iron (FE) and folic acid (FOLAC) has been mandatory in Brazil since 2004. However, there is no national Food Composition Table (nFCT) with comprehensive data on Brazilian fortified foods. This study aimed to elaborate a standardized dataset on FE and FOLAC content for fortified foods, according to fortification practices in Brazil. The content of added nutrients was estimated for all foods listed in the National Dietary Survey (NDS) using the recipe or ingredient list methods, borrowing from labels or imputing values from similar foods. Average consumption of FE and dietary folate equivalent (FOLDFE) was estimated by applying the developed dataset and a nFCT to consumption data from the NDS. The elaborated dataset comprises 140 food products and composite dishes including data for those most consumed in Brazil. The estimated average intake in the regions was 13-22% lower for FE and 19-35% lower for FOLDFE when the elaborated dataset was not included in the calculation. The elaborated dataset may allow for the evaluation of the impact of mandatory fortification of flours in Brazil. The same approach can be used in other countries to improve national data on fortified foods.

Long Range (LoRa) systems have recently attracted significant attention within the research community as well as for commercial use due to their ability to transmit data over long distances at a relatively low energy cost. In this study, new results for the bit error rate performance of Long Range (LoRa) systems operating in the presence of Rayleigh, Rice, Nakagami-m, Hoyt, η-μ and generalized fading channels are presented. Specifically, we propose novel exact single integral expressions as well as simple, accurate expressions that yield tight results in the entire signal-to-noise ratio (SNR) region. The validity of our newly derived formulas is substantiated by comparing numerically evaluated results with equivalent ones, obtained using Monte-Carlo simulations and exact analytical expressions.

Pneumonia causes the deaths of over a million people worldwide each year, with most occurring in countries with limited access to expensive but effective diagnostic methods, e.g., chest X-rays. Physical examination, the other major established method of diagnosis, suffers from several drawbacks, most notably low accuracy and high interobserver error. We sought to address this diagnostic gap by developing a proof-of-concept non-invasive device to identify the accumulation of fluid in the lungs (consolidation) characteristic of pneumonia. This device, named Tabla after the percussive instrument of the same name, utilizes the technique of auscultatory percussion; a percussive input sound is sent through the chest and recorded with a digital stethoscope for analysis. Tabla analyzes differences in sound transmission through the chest at audible frequencies as a marker for lung consolidation. This paper presents preliminary data from five pneumonia patients and eight healthy subjects. We demonstrate 92.3% accuracy in distinguishing between healthy subjects and patients with pneumonia after data analysis with a K-nearest neighbors algorithm. This prototype device is low cost and simple to implement and may offer a rapid and inexpensive method for pneumonia diagnosis appropriate for general use and in areas with limited medical infrastructure.

Pneumonia causes the deaths of over a million people worldwide each year, with most occurring in countries with limited access to expensive but effective diagnostic methods, e.g., chest X-rays. Physical examination, the other major established method of diagnosis, suffers from several drawbacks, most notably low accuracy and high interobserver error. We sought to address this diagnostic gap by developing a proof-of-concept non-invasive device to identify the accumulation of fluid in the lungs (consolidation) characteristic of pneumonia. This device, named Tabla after the percussive instrument of the same name, utilizes the technique of auscultatory percussion; a percussive input sound is sent through the chest and recorded with a digital stethoscope for analysis. Tabla analyzes differences in sound transmission through the chest at audible frequencies as a marker for lung consolidation. This paper presents preliminary data from five pneumonia patients and eight healthy subjects. We ...

The demand for interdisciplinary research is increasing in the new millennium to help us understand complex problems and find solutions by integrating the knowledge from different disciplines. The present review is an excellent example of this and shows how unique combination of physics, chemistry, and biological techniques can be used for the evaluation of Indian medicinal herbs used for treating diabetes mellitus. Laser-induced breakdown spectroscopy (LIBS) is a sensitive optical technique that is widely used for its simplicity and versatility. This review presents the most recent application of LIBS for detection of glycemic elements in medicinal plants. The characteristics of matrices, object analysis, use of laser system, and analytical performances with respect to Indian herbs are discussed.

Two-dimensional materials are crystalline materials consist of a single layer of atoms and sometimes referred to as single layer materials. Electrocatalytic energy conversion using renewable power sources is one of the most promising ways for energy storage and energy utilization in the new century. Over the past years, a great number of two-dimensional (2D) materials have been explored for various electrocatalytic reactions, such as the hydrogen evolution reaction, Carbon (IV) oxide (CO 2 ) reduction reaction and Oxygen (O 2 ) reduction reaction. This research provides an overview on the synthesis techniques of materials including bottom up approaches such as chemical vapor deposition (CVD) and physical vapor deposition (PVD) and top-down approaches like mechanical exfoliation, chemical exfoliation. Then, the characterization techniques of the two-dimensional (2D) materials such as Raman spectroscopy, X-ray diffraction, temperature-dependent resistivity and magnetic susceptibility and scanning tunneling microscopy (STM) are reviewed. Finally, potential applications of two-dimensional (2D) materials and conclusion, challenges and future work are discussed.

Hippocampus atrophy is an early structural feature that can be measured from magnetic resonance imaging (MRI) to improve the diagnosis of neurological diseases. An accurate and robust standardized hippocampus segmentation method is required for reliable atrophy assessment. The aim of this work was to develop and evaluate an automatic segmentation tool (DeepHarp) for hippocampus delineation according to the ADNI harmonized hippocampal protocol (HarP). DeepHarp utilizes a two-step process. First, the approximate location of the hippocampus is identified in T1-weighted MRI datasets using an atlas-based approach, which is used to crop the images to a region-of-interest (ROI) containing the hippocampus. In the second step, a convolutional neural network trained using datasets with corresponding manual hippocampus annotations is used to segment the hippocampus from the cropped ROI. The proposed method was developed and validated using 107 datasets with manually segmented hippocampi accord...

Suitability of TBP for recovery of uranium(VI) from dilute HNO 3 using LEM extraction is investigated. TBP co-extracts significant amount of HNO 3 along with U(VI). Beyond a critical time, extraction of U(VI) ceases due to attainment of critical acid level when the strip phase is unable to break TBP-U(VI) complex. The observed critical time is in good agreement with that estimated from rate of acid extraction. Optimal conditions at which the relative extraction of HNO 3 is minimal with respect to U(VI) is arrived at. The extraction efficiency of TBP is compared with other ligands viz., TiAP, TEHP, TOPO, TOA and D2EHPA.

The response surface methodology is used to obtain optimal rate and extent of extraction of low concentration U(VI) (B100 mg/L) by liquid emulsion membrane technique. Three different ligands viz. Tri-n-octyl phosphine oxide (TOPO), Tri-n-octyl amine (TOA) and Di-(2-ethylhexyl)phosphoric acid (D2EHPA), are used. 2 3 factorial design is applied to generate second order regression equation for studying the effect of concentration of ligand, surfactant and feed acidity. The regression model is in good agreement with the experimental data for all ligands. The rate of extraction of U(VI) by LEM is found to be in the order TOA [ TOPO [ D2EHPA.

In this study, the functionalization of diamond-like carbon (DLC) with carboxyl (COOH), hydroxyl (OH) and amine (NH₂) groups was investigated to understand its impact on the structural, electronic and nonlinear optical (NLO) properties. Dispersion-corrected density functional theory (DFT-D) calculations using the B3LYP-D3(BJ) exchange-correlation functional were performed in all calculations. The results indicated that functionalization with these groups enhanced the reactivity of the DLC surface. Molecular reactivity descriptors revealed that COOH-DLC exhibited the highest softness (S = 0.25 eV), significant electrophilicity (ω = 2.55 eV) and a reduced energy gap (∆E g = 3.97 eV). Time-dependent DFT (TD-DFT) analysis showed that COOH-DLC achieved the maximum absorption wavelength among the systems investigated. Additionally, functionalization improved the NLO properties, including increased polarity, with COOH-DLC displaying the highest first hyperpolarizability value. Natural bond orbital (NBO) analysis indicated significant orbital delocalization between the functional groups and the pristine DLC surface. Quantum theory of atoms in molecules (QTAIM) and non-covalent interaction (NCI) analyses, based on the reduced density gradient (RDG), provided a detailed characterization of interactions, highlighting the presence of van der Waals forces.

Selected chemometric methods were used to form models that define the qualitative and quantitative dependence between the chemical structure and the parameters of potential biological activity (lipophilicity, retention, pharmacokinetic, and toxic properties) of the selected diphenylacetamide derivatives. The chromatographic retention parameters of the selected diphenylacetamides were determined by applying reversed-phase thin-layer chromatography (RPTLC) on C18 and cyano modified carriers in mixtures of water-methanol and water-acetone. It was found that the polarity of the substituent R has dominant influence and its electronic effects to a lesser extent, on the studied parameters of the biological activity of diphenylacetamides. Also, results suggest a better similarity of the retention constants, R M 0 , with parameters of lipophilicity and pharmacokinetic predictors. Contrary to that, chromatographic parameter, m, exhibits a greater resemblance with toxicity parameters.

Sickle cell haemoglobin differs from normal haemoglobin by a single amino aeid in its (} chain. This amino acid replacement, from glutamic aeid to valine, causes polymerisation of proteins into defined long insoluble fibres with a typical diameter of 21.5 nm. The polymerisation is triggered by the formation of d eo \\h aem o g lo b in from oxyhaemoglobin in low oxygen partial pressures, which results in a conformational change in the secondary structure o f the protein. Pathogenesis in sickle cell disease depends on the polymerisation and gelation of deoxygenated HbS molecules. In this work, an electrochemical method has been described to modulate the oxygen concentration in an optically transparent thin layer cell to produce deoxyhaemoglobin whilst monitoring the extent o f polymerisation using turbidity measurements. The oxygen was depleted in the vicinity o f the electrode and triggered the polymerisation. The dependence o f protein concentration, temperature. pH and ionic strength on the nucleation and elongation o f HbS polymerisation was characterised at the electrode surface and the kinetics of polymerisation was investigated using a model for fibrillogenesis describing a twostep process of nucleation followed by elongation. The rate constants, determined for a number of conditions, showed that nucleation is far slower than the growth whilst polymerisation at the surface was demonstrated to occur in three stages, with an initial time delay when no structures were observed followed b\ growth of fibrous hair-like strands and finally gel-like aggregation. An understanding of the factors which affect polymerisation at a surface and an insight into the dynamics and mechanism o f polymer aggregation and the pathophysiology o f sickle cell disease has been provided. A screening method for substances that effect the fibre nucleation and/or growth that could be valuable to the pharmaceutical industry for treating sickle cell disease is also presented. Chapter 1: Introduction 1.1 Sickle Cell Anaemia Sickle cell anaemia (SCA) is the most common type o f a group o f autosomal recessive disorders termed as sickle cell disease (SCD). It is a genetic disorder o f the blood in which the red blood cells (RBC) curve into a sickle shape due to the production and, most importantly, polymerisation o f mutant sickle haemoglobin (HbS). It is a disease which afflicts millions o f people throughout the world, in particular those whose ancestors come from equatorial regions such as sub-Saharan Africa, Saudi Arabia, South America and India, and clinical manifestations include amongst others severe haemolytic anaemia, pain crises, stroke, and chronic damage to vital organs such as lungs, kidneys and liver. The fundamental process o f HbS polymerisation inside sickle erythrocytes has been studied by almost every physical technique o f protein chemistry, including electron microscopy, single-crystal X-ray diffraction, nuclear magnetic resonance, circular dichroism spectroscopy, laser photolysis and temperature jum p kinetics. A large part of the success in understanding this process can be attributed to the application of these many different techniques. However, even though the polymerisation o f HbS has probably become the best understood o f all protein selfassembly systems, SCA is still a major global health problem, with an estimated 120,000 to 250,000 affected infants born annually [1], and at present most clinical interventions can be classified as tertiary prevention, such as therapies to ameliorate anaemia, reduction o f the frequency o f pain crises, or prevention o f stroke recurrences. As o f yet, there are no preventative treatments. In this chapter, recent advances into the study o f HbS polymerisation, it's structural and physical properties as well as the critical conditions required for polymer formation, are described. Electrochemistry is also introduced and a summary o f relevant visualisation techniques is reported.

Graphene nanoflakes (GNF) with lateral dimensions of ca. 30 nm and edge-terminated with carboxylic acid functionalities have been characterised and the influence of acidic functionalities on the [Fe(CN) 6 ] 3À/4À redox couple studied using cyclic voltammetry and spectroelectrochemical methods. The presence of the COOH-terminated GNF in solution as well as immobilised onto an electrode surface was found to inhibit the redox reaction, supporting the conclusion that GNF promote instability of [Fe(CN) 6 ] 3À/4À in solution. The redox reaction was also much less influenced by the presence of GNF in D 2 O, highlighting the role played by readily available protons in destabilising the [Fe(CN) 6 ] 3À/4À redox couple. In the presence of GNF in solution, an additional, very intense cyanide stretch IR band was observed that was attributed to the formation of a new, non-soluble species. When D 2 O was used as the solvent, the IR spectrum showed no evidence of a new cyano species.

Sickle cell haemoglobin differs from normal haemoglobin by a single amino aeid in its (} chain. This amino acid replacement, from glutamic aeid to valine, causes polymerisation of proteins into defined long insoluble fibres with a typical diameter of 21.5 nm. The polymerisation is triggered by the formation of d eo \\h aem o g lo b in from oxyhaemoglobin in low oxygen partial pressures, which results in a conformational change in the secondary structure o f the protein. Pathogenesis in sickle cell disease depends on the polymerisation and gelation of deoxygenated HbS molecules. In this work, an electrochemical method has been described to modulate the oxygen concentration in an optically transparent thin layer cell to produce deoxyhaemoglobin whilst monitoring the extent o f polymerisation using turbidity measurements. The oxygen was depleted in the vicinity o f the electrode and triggered the polymerisation. The dependence o f protein concentration, temperature. pH and ionic strength on the nucleation and elongation o f HbS polymerisation was characterised at the electrode surface and the kinetics of polymerisation was investigated using a model for fibrillogenesis describing a twostep process of nucleation followed by elongation. The rate constants, determined for a number of conditions, showed that nucleation is far slower than the growth whilst polymerisation at the surface was demonstrated to occur in three stages, with an initial time delay when no structures were observed followed b\ growth of fibrous hair-like strands and finally gel-like aggregation. An understanding of the factors which affect polymerisation at a surface and an insight into the dynamics and mechanism o f polymer aggregation and the pathophysiology o f sickle cell disease has been provided. A screening method for substances that effect the fibre nucleation and/or growth that could be valuable to the pharmaceutical industry for treating sickle cell disease is also presented. Chapter 1: Introduction 1.1 Sickle Cell Anaemia Sickle cell anaemia (SCA) is the most common type o f a group o f autosomal recessive disorders termed as sickle cell disease (SCD). It is a genetic disorder o f the blood in which the red blood cells (RBC) curve into a sickle shape due to the production and, most importantly, polymerisation o f mutant sickle haemoglobin (HbS). It is a disease which afflicts millions o f people throughout the world, in particular those whose ancestors come from equatorial regions such as sub-Saharan Africa, Saudi Arabia, South America and India, and clinical manifestations include amongst others severe haemolytic anaemia, pain crises, stroke, and chronic damage to vital organs such as lungs, kidneys and liver. The fundamental process o f HbS polymerisation inside sickle erythrocytes has been studied by almost every physical technique o f protein chemistry, including electron microscopy, single-crystal X-ray diffraction, nuclear magnetic resonance, circular dichroism spectroscopy, laser photolysis and temperature jum p kinetics. A large part of the success in understanding this process can be attributed to the application of these many different techniques. However, even though the polymerisation o f HbS has probably become the best understood o f all protein selfassembly systems, SCA is still a major global health problem, with an estimated 120,000 to 250,000 affected infants born annually [1], and at present most clinical interventions can be classified as tertiary prevention, such as therapies to ameliorate anaemia, reduction o f the frequency o f pain crises, or prevention o f stroke recurrences. As o f yet, there are no preventative treatments. In this chapter, recent advances into the study o f HbS polymerisation, it's structural and physical properties as well as the critical conditions required for polymer formation, are described. Electrochemistry is also introduced and a summary o f relevant visualisation techniques is reported.

L L -3-Hydroxybutyrate (L L -3HB), the enantiomer of D D -3-hydroxybutyrate (D D -3HB), has traditionally been regarded the ''unnatural'' ketone body in mammals, although there is suspicion that it is a more-favorable energy fuel for mammalian tissues than D D -3HB. In this study, we demonstrated that L L -3HB is an original substance in rat serum by applying fluorescence derivatization and a columnswitching high-performance liquid chromatography system as the analysis technique. Racemic 3HB in rat serum derivatized using 4-nitro-7-piperazino-2,1,3-benzoxadiazole was first separated by an ODS column and was further confirmed by verifying the disappearance of the racemic 3HB peak after pretreating rat serum with D D -3-hydroxybutyryl dehydrogenase. A switching valve was used to simultaneously introduce isolated racemic 3HB to the enantiomeric separation by two CHIRALCEL OD-RH columns connected in tandem. An L L isomer was found to accompany the D D isomer, which were quantified to be 3.98 lM (3.61%) and 106.20 lM (96.39%), respectively. Using the present analytical method, the dubious interpretation of the existence of L L -3HB was clarified.

A highly sensitive method for the fluorimetric determination of d-lactate in urine of normal and diabetic rats was developed using columnswitching high-performance liquid chromatography (HPLC) with an octadecylsilica (ODS) column connected to a chiral column, an amylose tris(3,5-dimethylphenylcarbamate) coated on silica gel (Chiralpak AD-RH). During the separation step on the ODS column, the peak fraction of the (d+l)-lactate derivative with a fluorescence reagent, 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ), was introduced directly to the chiral column by changing the flow of the eluent via a six-port valve. The d-lactate derivative was separated enantiomerically from the l-lactate derivative, and the enantiomeric ratio was determined from the chromatogram. The accuracy values for the determination of d-lactate in 20 L of rat urine were 96.93-104.85%, and the intra-and inter-day precision values were within 0.80 and 14.44%, respectively. The detection limit for d-lactate was approximately 10 nM (with a signal-to-noise ratio of 3). The proposed HPLC method was applied to the urine of normal and diabetic rats induced by intraperitoneal administration of streptozotocin, and significant increases in d-lactate excreted into the urine were observed in diabetic rats compared to normal rats. In diabetic rats, d-lactate concentrations showed a rising tendency from the seventh day and then remained stable from the 28th day after induction, suggesting that urinary d-lactate may be used as an indicator to determine the diabetic stage and the level of kidney damage.

This study aims to explore the applicability of diffuse ultrasound to the evaluation of water permeability and chloride ion penetrability of cracked concrete. Lab-scale experiments were conducted on disk-shaped concrete specimens, each having a different width of a penetrating crack that was generated by splitting tension along the centerline. The average crack width of each specimen was determined using an image binarization technique. The diffuse ultrasound test employed signals in the frequency range of 200 to 440 kHz. The water flow rate was measured using a constant water-head permeability method, and the chloride diffusion coefficient was determined using a modified steady-state migration method. Then, the effects of crack width on the diffusion characteristics of ultrasound (i.e., diffusivity, dissipation), water flow rate, and chloride diffusion coefficient are investigated. The correlations between the water flow rate and diffuse ultrasound parameters, and between the chloride diffusion coefficient and diffuse ultrasound parameters, are examined. The results suggest that diffuse ultrasound is a promising method for assessing the water permeability and chloride ion penetrability of cracked concrete.

We investigated an optical microsensor of the polarization state of a laser light based on a metalens. In contrast to known polarization sensors based on metasurfaces that deflect different polarization types using various angles to the optical axis, the studied polarization sensor generated different patterns in the metalens focus to realize varied polarization states: left circular polarization generated a light ring in the focus, right circular polarization generated a circular focal spot, and linear polarization generated an elliptic spot with two sidelobes. Moreover, the tilt angle of the linear polarization matched the tilt angle of the elliptic focal spot. The simulation results were consistent with the theoretical predictions. A metalens with a diameter of several tens of microns was designed and fabricated in a thin amorphous silicon film with a thickness of 120 μm and a low aspect ratio, high numerical aperture, and short focal distance equal to a wavelength of 633 nm.

Finding a proper balance between video quality and the required bandwidth is an important issue, especially in networks of limited capacity. The problem of comparing the efficiency of video codecs and choosing the most suitable one in a specific situation has become very important. This paper proposes a method of comparing video codecs while also taking into account objective quality assessment metrics. The author shows the process of preparing video footage, assessing its quality, determining the rate–distortion curves, and calculating the bitrate saving for pairs of examined codecs. Thanks to the use of the spline interpolation method, the obtained results are better than those previously presented in the literature, and more resistant to the quality metric used.

Finding a proper balance between video quality and the required bandwidth is an important issue, especially in networks of limited capacity. The problem of comparing the efficiency of video codecs and choosing the most suitable one in a specific situation has become very important. This paper proposes a method of comparing video codecs while also taking into account objective quality assessment metrics. The author shows the process of preparing video footage, assessing its quality, determining the rate-distortion curves, and calculating the bitrate saving for pairs of examined codecs. Thanks to the use of the spline interpolation method, the obtained results are better than those previously presented in the literature, and more resistant to the quality metric used.

Surface enhanced Raman spectroscopy has many advantages over its parent technique of Raman spectroscopy. Some of these advantages such as increased sensitivity and selectivity and therefore the possibility of small sample sizes and detection of small concentrations are invaluable in the field of forensics. A variety of new SERS surfaces and novel approaches are presented here on a wide range of forensically relevant topics.

Efficient and optimal design of radar-based Advanced Driver Assistant Systems (ADAS) needs the evaluation of many different electromagnetic solutions for evaluating the impact of the radome on the electromagnetic wave propagation. Because of the very high frequency at which these devices operate, with the associated extremely small wavelength, very fine meshes are needed to accurately discretize the electromagnetic equations. Thus, the computational cost of each numerical solution for a given choice of the design or operation parameters, is high (CPU time consuming and needing significant computational resources) compromising the efficiency of standard optimization algorithms. In order to alleviate the just referred difficulties the present paper proposes an approach based on the use of reduced order modeling, in particular the construction of a parametric solution by employing a non-intrusive formulation of the Proper Generalized Decomposition, combined with a powerful phase-angle ...

Chalcogen analogues of nicotine lactam have been studied. Delocalized structure of oxo and thionicotine becomes weaker in the resonance structure of selenonicotine. Unlike the nicotine and its derivatives, the chalcogen lactams of nicotine are prone to pÁ Á Áp stacking. The article provides characteristics of the most widely used biomarker of nicotine intake -cotinine and its congeners.

Variations in 234 U/ 238 U have wide-ranging applications as tracers for ground-and river-water fluxes and is an essential component in U-series dating. Analytical developments for measuring 234 U/ 238 U have progressed from direct alpha-counting, with precisions at the percent level, to thermal ionization and multiple-collector inductively coupled plasma mass spectrometry (TIMS and MC-ICPMS, respectively) isotopic measurement techniques. However, 234 U/ 238 U is difficult to measure with better than permil precision because of the small atomic ratios for most geological samples (∼10 -4 range). Using a Nu Instruments Nu Plasma MC-ICPMS, we have developed two analytical techniques for the precise measurement of 234 U/ 238 U: (1) a conventional standard-bracketing protocol using multiple Faraday cups and electron multipliers with ion counting capabilities (FM) and (2) a standard-bracketing Faraday cup protocol (FF). Both are capable of measuring 234 U/ 238 U with precisions at the epsilon level (1 epsilon = 1 part in 10 4 ): (1) The conventional standard-bracketing FM measurements are conducted as static measurements with the minor 234 U isotope measured in a conventional discrete dynode electron multiplier (SEM) equipped with ion counter and a retardation filter. The Faraday-multiplier gain is measured using bracketing measurements of the U metal standard CRM-145. The external reproducibility of 234 U/ 238 U (reformulated into δ-notation as δ 234 U), interspersed with frequent measurements of the gain, is at the ±0.6‰ level (2σ) for both uraninite and carbonate standards, takes ∼75 min and consumes ∼120 ng of U per measurement. (2) The static standard-bracketing FF protocol measures all three natural U isotopes in Faraday collectors. This is not usually possible using a standard multiple-Faraday array due to the large differences in the abundances of naturally occurring U isotopes. In our study, this is achieved by replacing the standard 10 11 resistor for the 238 U Faraday cup with a 10 9 resistor. The 10 9 resistor enables the measurement of ion beams that are ∼100 times larger than can be accommodated by the normal 10 11 resistor, so 238 U and 234 U are measured simultaneously in Faraday cups with intensities of ∼9 × 10 -9 and ∼5 × 10 -13 A, respectively. All measurements are normalized to bracketing CRM-145 standard measurements (measured with similar 238 U signal intensities) thereby correcting for significant tailing from the large 238 U ion beam below the smaller 234 U beam. Measurements are conducted over 2 min on-peak and 400-650 ng of 238 U is required per analysis. External reproducibility for samples with low matrix/U ratios (e.g., uraninites) is better than ±0.3‰ (2σ). Coral samples show a slightly poorer external reproducibility of ±0.4‰ (2σ) due to a higher matrix/U ratios of these samples. Repeat measurements of CRM-145 give respective δ 234 U values of -36.44 ± 0.10‰ (2σ m , n = 9) and -36.50 ± 0.14‰ (2σ m , n = 54) using the FF and FM analytical technique, assuming Harwell uraninite (HU-1) is in secular equilibrium with respect to 234 U/ 238 U. The improved analytical precision achieved in this study for 234 U/ 238 U measurement is superior to any other reported measurements and is of great importance for U-series dating errors, particularly for samples older than 300,000 years before present.

Novel chitosan scaffolds containing different weight ratios of electrospun hydroxyapatite nanofibers (n-HA) were fabricated. The fibers possessed diameters in the range of 110-170 nm. A fixed concentration of glycidyloxypropyl-trimethoxysilane (GPTMS) as a crosslinking agent was added to the chitosan solution (CG). The porosity percentage was increased when GPTMS and n-HA were added to the chitosan structure. The presence of GPTMS in chitosan structure caused a decrease in the average pore size. The pores were more irregular in shape than pure chitosan and CG scaffolds when n-HA was added. The uniform distribution of n-HA was seen for chitosan-GPTMS hybrid scaffold containing 25 wt% n-HA (CGH25) using EDS spectrum and mapping. The best values of compressive strength and elastic modulus were achieved for CGH25. The swelling ratio was decreased by adding GPTMS in the chitosan scaffold. Different morphologies of hydroxyapatite deposits on the surface of CG and CGH25 (string-like versus needle-like precipitates) were observed after 14 days of soaking in simulated body fluid (SBF). For CGH25, the viability of MG-63 osteoblastic cells was approximately varied with respect to CG up to 72h of cell culture. These results reveal the potential of the chitosan-CGH25 scaffold to be used in bone tissue engineering.

Novel chitosan scaffolds containing different weight ratios of electrospun hydroxyapatite nanofibers (n‐HAs) were fabricated. The fibers possessed diameters in the range 110–170 nm. A fixed concentration of glycidyloxypropyl‐trimethoxysilane (GPTMS) as a crosslinking agent was added to the chitosan solution (CG). The porosity percentage was increased when GPTMS and n‐HAs were added to the chitosan structure. The presence of GPTMS in the chitosan structure caused a decrease in the average pore size. The pores were more irregular in shape than pure chitosan and CG scaffolds when n‐HAs were added. A uniform distribution of n‐HAs was seen for a chitosan‐GPTMS hybrid scaffold containing 25 wt% n‐HAs (CGH25) using energy dispersive X‐ray spectroscopy and mapping. The best values of compressive strength and elastic modulus were achieved for CGH25. The swelling ratio was decreased on adding GPTMS to the chitosan scaffold. Different morphologies of hydroxyapatite deposits on the surface of C...