A Review of Natural Plants as Sources of Substances for Cleaner Leather Tanning Technologies

The stringent environmental regulations and compliance regarding leather tanning has compelled leather industry to seek alternative cleaner ingredients that have the capacity to minimize or prevent pollution caused by hazardous chemicals. Practical measures have so far involved replacing the current use of synthetic chemicals such as chromium salts, dyes, fatliquors and surfactants or minimizing their usage by incorporating agrobased organic components. Numerous papers have documented the use of different plant extracts at different stages of leather processing such as tanning, retanning, dyeing and fatliquoring. This present article details the specific plants and the leather processing stage at which they are applied and eventually the quality of the resulting leather. This article attempts to compile a considerable number of investigations published on physical properties of leather that is processed using natural plants. It has been shown that there are striking similarities in leather properties of leather processed using natural plants and using synthetic chemicals. This could help in compiling a database that details works on natural plants, stages of application and the corresponding physical properties which could provide a crucial assistance to research focusing on environmental protection and physical properties of leather which would in turn improve the quality of the resulting leather

Label-free assaying of testosterone and growth hormones in blood using surface-enhanced raman spectroscopy

This work reports the potential use of surface enhanced Raman spectroscopy (SERS) in rapid, label-free assaying of testosterone (TE) and growth hormone (GH) in whole blood. Biomarker SERS spectral bands from the two hormones (TE and GH) in intentionally spiked water for injection and in male Sprague-Dawley (SD) rat blood are reported. Abuse of the two hormones (TE and GH) singly or simultaneously is widespread and not only has prolonged side effects such as hypertension and liver failure, but their illegal use by athletes is against clean competition. Currently used highly label-dependent doping detection methods involve complex and time-consuming procedures, rendering them unsuitable for rapid analysis. In blood, the most concentration-sensitive bands (in both TE and GH), as deduced through Principal Component Analysis (PCA) and Analysis of Variance (ANOVA), were around 684 cm-1 (assigned to C-C stretching) and 1614 cm-1 (assigned to C-C stretching) in GH; and 786 cm-1 (assigned to N-H wagging), 856 cm-1 (assigned to C-C stretching), and 1490 cm-1 (assigned to CH2 bending) in TE. In addition, a characteristic variance was noted in the bands around 1510 cm-1 (attributable to CH2 stretching) in GH and 1636 cm-1 (C-C stretching) in TE, which could be used as biomarker bands for the respective hormones in the blood. This work has shown the capability of SERS for potential hormone concentration level determination when concentration-sensitive or biomarker bands are employed. This discovery opens new possibilities for the use of SERS in fields such as sports science, clinical diagnostics, and biomedical research

Use of Organic Binders to Enhance Defluoridation and Pathogen Removal Efficiency of Diatomaceous Earth-Based Ceramic Filters

The use of diatomaceous earth, DE, ceramic membranes in water purification has been in existence for centuries. However, the DE-based membranes are brittle, ineffective in the defluoridation, and disinfection of water. The aim of this work is to improve the mechanical strength, water defluoridation, and filtration efficiency of DE-based ceramic membrane using organic binders; Abelmoschus esculentus, Aloe vera, and Basella alba. The ceramic membranes were fabricated from DE-powder and plant-based organic binders with a ratio of 2:1 by mass. The dried samples were fired at 700.0 to 1150.0 °C. The fabricated membranes were then made to filter water contaminated with Escherichia coli, Rotavirus, and sodium fluoride. The results showed the DE-powder was characterized by 87.5%; 4.0% and 89.6; 2.9% silica and aluminum oxides for DE-A and DE-B respectively. Basella alba binder showed the highest content of organic matter and formed the strongest membranes with the highest efficiency. Basella alba was able to improve the modulus of rupture, defluoridation, and virus removal efficiency of the DE-B membranes by 84.8%, 30.9%, and 40.3% respectively. DE-B-powder plus Basella alba are potential materials in ceramic membranes as they were able to defluoridate by 89.2% and remove Rotavirus by 98.3% from water

Exciton dynamics in tetracene single crystals studied using femtosecond laser spectroscopy

Thesis (PhD)--Stellenbosch University, 2012.ENGLISH ABSTRACT: See full textAFRIKAANSE OPSOMMING: Sien voltek

Ultrafast dynamics of excitons in tetracene single crystals

Please cite as follows: Birech, Z., Schwoerer, M., Schmeiler, T., Pflaum, J. & Schwoerer, H. 2014. Ultrafast dynamics of excitons in tetracene single crystals. Journal of Chemical Physics, 140, 114501, doi:10.1063/1.4867696.The original publication is available at http://scitation.aip.org/content/aip/journal/jcpUltrafast exciton dynamics in free standing 200 nm thin tetracene single crystals were studied at room temperature by femtosecond transient absorption spectroscopy in the visible spectral range. The complex spectrally overlapping transient absorption traces of single crystals were systematically deconvoluted. From this, the ultrafast dynamics of the ground, excited, and transition states were identified including singlet exciton fission into two triplet excitons. Fission is generated through both, direct fission of higher singlet states S n on a sub-picosecond timescale, and thermally activated fission of the singlet exciton S 1 on a 40 ps timescale. The high energy Davydov component of the S 1 exciton is proposed to undergo fission on a sub-picoseconds timescale. At high density of triplet excitons their mutual annihilation (triplet-triplet annihilation) occurs on a <10 ps timescale.http://scitation.aip.org/content/aip/journal/jcp/140/11/10.1063/1.4867696Publisher's versio

Multi-Channel Optoelectronic Measurement System for Soil Nutrients Analysis

To solve the problems that occur when farmers overuse chemical fertilizers, it is necessary to develop rapid and efficient portable measurement systems for the detection and quantification of nitrogen (N), phosphorus (P), and potassium (K) in soil. Challenges arise from the use of currently available portable instruments which only have a few channels, namely measurement and the reference channels. We report on a home-built, multichannel, optoelectronic measurement system with automatically switching light sources for the detection of N, P, K content in soil samples. This optoelectronic measurement system consists of joint LED light sources with peak emission wavelengths of 405 nm, 660 nm, and 515 nm, a photodiode array, a circuit board with a microcontroller unit (MCU), and a liquid-crystal display (LCD) touch screen. The straightforward principle for rapid detection of the extractable nutrients (N, P, K) was well-established, and characterization of the designed measurement system was done. Using this multi-channel measurement system, available nutrients extracted from six soil samples could be measured simultaneously. The absorbance compensation, concentration calibration, and nutrition measurements were performed automatically to achieve high consistency across six channels. The experimental results showed that the cumulative relative standard deviations of 1.22%, 1.27%, and 1.00% were obtained from six channels with known concentrations of standard solutions, respectively. The coefficients of correlation for the detection of extracted nutrients of N, P, K content in soil samples using both the proposed method and conventional lab-based method were 0.9010, 0.9471, and 0.8923, respectively. Experimental results show that this optoelectronic measurement system can perform the measurement of N, P, K contents of six soil samples simultaneously and may be used as an actual tool in determining nutrients in soil samples with an improvement in detection efficiency

Figure showing the changes in the mean Raman intensity of diabetic SD rat’s blood at bands centered at wavenumbers 1125, 1395 and 1437 cm⁻¹ assigned to glucose, leucine and isoleucine respectively after giving them anti-diabetic drugs pioglitazone and herbal extracts at concentrations of 200 mg/kg (Ms200) and 400 mg/kg (Ms400) of body weight.

<p>The intensities decreased with administration of anti-diabetic drugs and extracts.</p

Application of Raman spectroscopy in type 2 diabetes screening in blood using leucine and isoleucine amino-acids as biomarkers and in comparative anti-diabetic drugs efficacy studies

<div><p>Diabetes is an irreversible condition characterized by elevated blood glucose levels. Currently, there are no predictive biomarkers for this disease and the existing ones such as hemoglobin A1c and fasting blood glucose are used only when diabetes symptoms are noticed. The objective of this work was first to explore the potential of leucine and isoleucine amino acids as diabetes type 2 biomarkers using their Raman spectroscopic signatures. Secondly, we wanted to explore whether Raman spectroscopy can be applied in comparative efficacy studies between commercially available anti-diabetic drug pioglitazone and the locally used anti-diabetic herbal extract <i>Momordica spinosa</i> (<i>Gilg</i>.)<i>Chiov</i>. Sprague Dawley (SD) rat’s blood was used and were pipetted onto Raman substrates prepared from conductive silver paste smeared glass slides. Prominent Raman bands associated with glucose (926, 1302, 1125 cm⁻¹), leucine (1106, 1248, 1302, 1395 cm⁻¹) and isolecucine (1108, 1248, 1437 and 1585 cm⁻¹) were observed. The Raman bands centered at 1125 cm⁻¹, 1395 cm⁻¹ and 1437 cm⁻¹ associated respectively to glucose, leucine and isoleucine were chosen as biomarker Raman peaks for diabetes type 2. These Raman bands displayed decreased intensities in blood from diabetic SD rats administered antidiabetic drugs pioglitazone and herbal extract <i>Momordica spinosa</i> (<i>Gilg</i>.)<i>Chiov</i>. The intensity decrease indicated reduced concentration levels of the respective biomarker molecules: glucose (1125 cm⁻¹), leucine (1395 cm⁻¹) and isoleucine (1437 cm⁻¹) in blood. The results displayed the power and potential of Raman spectroscopy in rapid (10 seconds) diabetes and pre-diabetes screening in blood (human or rat’s) with not only glucose acting as a biomarker but also leucine and isoleucine amino-acids where intensities of respectively assigned bands act as references. It also showed that using Raman spectroscopic signatures of the chosen biomarkers, the method can be an alternative for performing comparative efficacy studies between known and new anti-diabetic drugs. Reports on use of Raman spectroscopy in type 2 diabetes mellitus screening with Raman bands associated with leucine and isoleucine molecules acting as reference is rare in literature. The use of Raman spectroscopy in pre-diabetes screening of blood for changes in levels of leucine and isoleucine amino acids is particularly interesting as once elevated levels are noticed, necessary interventions to prevent diabetes development can be initiated.</p></div

Table showing the center wavenumbers of the prominent Raman bands in the spectra from mainly diabetic SD rat’s blood, leucine and isoleucine amino acids and their tentative assignments.

<p>Table showing the center wavenumbers of the prominent Raman bands in the spectra from mainly diabetic SD rat’s blood, leucine and isoleucine amino acids and their tentative assignments.</p