Surface-enhanced Raman spectroscopy (SERS) combines molecular fingerprint specificity with potential single-molecule sensitivity. Therefore, the SERS technique is an attractive tool for sensing molecules in trace amounts within the field of chemical and biochemical analytics. Since SERS is an ongoing topic, which can be illustrated by the increased annual number of publications within the last few years, this review reflects the progress and trends in SERS research in approximately the last three years. The main reason why the SERS technique has not been established as a routine analytic technique, despite its high specificity and sensitivity, is due to the low reproducibility of the SERS signal. Thus, this review is dominated by the discussion of the various concepts for generating powerful, reproducible, SERS-active surfaces. Furthermore, the limit of sensitivity in SERS is introduced in the context of single-molecule spectroscopy and the calculation of the 'real' enhancement factor. In order to shed more light onto the underlying molecular processes of SERS, the theoretical description of SERS spectra is also a growing research field and will be summarized here. In addition, the recording of SERS spectra is affected by a number of parameters, such as laser power, integration time, and analyte concentration. To benefit from synergies, SERS is combined with other methods, such as scanning probe microscopy and microfluidics, which illustrates the broad applications of this powerful technique.

Surface-enhanced Raman spectroscopy (SERS): progress and trends

This work was supported by the Christian Doppler Research Association (Austrian Federal Ministry of Science, Research and Economy and the National Foundation for Research, Technology and Development), the OMV Group (to E.R.), the EPSRC (DTA studentships for D.W.W. and T.E.R), the Isaac Newton Trust, the German Research Foundation (to M.F.K.), the World Premier Institute Research Center Initiative (WPI), MEXT, Japan (to K.L.O.) and a Marie Curie Research fellowship (to K.H.L., GAN 701192 - VSHER).

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Solar-driven reforming of lignocellulose to H 2 with a CdS/CdO x photocatalyst

Xerographic photoreceptors charge acceptance and dark discharge photoinduced discharge photogeneration theories photogeneration in organic solids charge transport theories charge transport in polymers and related materials experimental techniques photoreceptor preparation photoreceptors fatigue summary and future requirements.

Organic Photoreceptors for Imaging Systems

Ed Lori B Andrews, Jane E Fullarton, Neil A Holtzman, Arno G Motulsky National Academy Press, £28.95, pp 338 ISBN 0-309-04798-6

Genetic screening tends to serve as a flypaper on which our hovering fears of a Brave New World alight and stick. In the future of all-conquering genetic technology, who should be screened for what and by whom? Here is a dense report, compiled by a committee of the great and the good, with hundreds of recommendations for action and inaction. How much …

Assessing Genetic Risks: Implications for Health and Social Policy

A review on nanostructured carbon quantum dots and their applications in biotechnology, sensors, and chemiluminescence.

Abstract The wavenumber difference (Δν) of the ring breathing mode (ν1), ring deformation mode (ν12) and C–H stretching mode (ν3) of pyridine (Py) dissolved in both H2O and D2O at equal mole fractions of the solute (Py) and the solvent (H2O/D2O) has been determined precisely by using the technique of Raman difference spectroscopy (RDS) in order to analyze the relative shift caused by these two solvents. The spectra of the two systems, for which the difference spectrum is to be generated, were recorded simultaneously and the wavenumber shifts up to almost one hundredth part of the linewidth of a band could be determined precisely. The values of Δν for the three modes as a function of mole fraction are compared with the Δν obtained by the solvation of Py molecule in the media of dielectric constants equal to that of the mixture of Py and H2O/D2O at the experimental mole fractions using DFT and MP2 methods. The variation in Δν with mole fraction seems to be the result of difference of dielectric constants of Py+H2O and Py+D2O at equal mole fraction. The absolute peak position and linewidth of the three modes as a function of mole fraction have been discussed in terms of relevant models, which show the effective role of diffusion and concentration fluctuation in the mixture.

Precise Analysis of Small Wavenumber Shift of Pyridine on Dilution with H2O and D2O Using RDS Technique

Stability constants of Zinc(II), Cobalt(ll), Uranyl(II) and Thorium(IV) have been determined by paper electrophoresis. Salicylic acid (0-005 mol dm ) was added to the background electrolyte: 0-1 m o l d m 3 H C I O * . T h e p ropor t ions of C 6 H T O H C O O \" a n d C 6 H » O C O O = were var ied b y c h a n g i n g the pH of the electrolyte. These anions yielded the complexes, ZnC6H<OHCOO, COC6HIOHCOO, ThiCsHiOHCOO)* and U0 2 (C 6 H 4 0C00) | whose stability constants are found to be 10, 10 J , 10 6 and 10\"respectively (/J = 01, temp. 40°Q.

Stability constants of salicylate of zinc(II), cobalt(II), uranyl(II) and thorium(IV) by paper electrophoresis

Stoichiometric stability constants of Th(IV), Cr(III) and AI(III) complexes of some amino acids have been determined by modified ionophoretic technique. Amino acid (1 x 10~ M) was added to background electrolyte: 0.1 mol d m 3 perchloric acid. The proportions of various species of the amino acids were varied by changing the pH of the background electrolyte. Anionic species of the amino acids yielded the completes, ThL 3 , CrL , CrLJ, CrL, , AIL, AILJ and A1L3 whose stability constants are reported.

Ionophoretic Technique in the Determination of Stability Constants

The application of detonation engines in hypersonic flight has gained significant attention in recent years due to their potential to revolutionize air travel, defense systems, and access to space and interstellar travel. One of the key benefits of detonation engines is their ability to operate efficiently at hypersonic speeds. Traditional engines struggle with the supersonic airflow encountered during hypersonic flight, leading to reduced efficiency and increased thermal loads. Despite their potential, implementing detonation engines for hypersonic flight presents numerous technical challenges. Achieving stable and controlled detonation in a compact and lightweight design remains a major hurdle. Additionally, managing the intense heat generated during the detonation process requires advanced cooling techniques and materials. The fuel-oxidizer combinations used under such conditions should be easily detonable and be able to sustain and propagate robust detonations over the entire operation cycle. In the current work, the detonability of hydrogen-oxygen/air mixtures is explored using one-dimensional ZND computations. Ozone and hydrogen peroxide are used as ignition promoters to enhance the ignition chemistry and also to evaluate their effect on the detonability of H2-O2/air mixtures. The lower and upper detonability limits for H2-O2/air gaseous mixtures were also evaluated for a range of dopant concentrations. The computed results show a promising solution to enhance the detonability of a given fuel-oxidizer mixture, thereby increasing the operating range of detonation-based engines. The increased efficiency and performance provided by detonation engines could enable faster and more cost-effective long-range transportation, opening up possibilities for rapid global connectivity. 

Enhancing the Detonability of H2–O2/Air Mixtures by Using O3 and H2O2 for Application in Detonation Engines

Sweet flag ( Acorus calamus ) is a well-known plant all over the world due to its specific bioactive components β- asarone in plants. The present study reports the quantitative estimation of rhizome oil of the sweet flag plant; obtain from the various district of Uttarakhand, and different geographical surroundings. GC-MS is used to estimate the quantity of rhizome oil. Although leaves are enriched by the several medicinal constituents revealed by the previous studies, rhizome, and the oil it is being investigated. The main component which was identified was Cis-ocimene, Linalool, Trans methyl isoeugenol, β and α-asarone, and euasarone. β-asarone in the different samples; showed a higher percentage as compared to another component. It was observed that the Gopeshwar region sample had the 74.36 least percentage and the Pauri sample had the 92.22 highest percentage of β-Asarone. Meanwhile, the Gopeshwar region sample had 17.25 highest percentage, and the Pauri sample had 1.57 least percentage of α-Asarone. Fungal infection is prevalent nowadays. The oil from all regions subjected to antifungal activity against the Aspirigilla fumigates, A. Parasiticus, Microsporum Canis, M. gypsum, Cladosporium, Aspergillus niger. The inhibition zone diameter (IZD) against Aspirigilla fumigates , A. parasiticus and was a maximum of 10cm for the Gopeshwar sample,9cm for the Ramnagar sample as compared to the reference drug gentamicin.

Comparative Analysis Of Chemical Constituent And Antimicrobial Potential Of Acorus Calamus Linn (Sweet Flag) In The Different Geographical Regions Of North Himalayas

Ranjan K. Singh

Papers

Precise Analysis of Small Wavenumber Shift of Pyridine on Dilution with H2O and D2O Using RDS Technique

Stability constants of salicylate of zinc(II), cobalt(II), uranyl(II) and thorium(IV) by paper electrophoresis

Ionophoretic Technique in the Determination of Stability Constants

Enhancing the Detonability of H2–O2/Air Mixtures by Using O3 and H2O2 for Application in Detonation Engines

Comparative Analysis Of Chemical Constituent And Antimicrobial Potential Of Acorus Calamus Linn (Sweet Flag) In The Different Geographical Regions Of North Himalayas