Search results for "Biological Materials"
showing 10 items of 27 documents
Strong Emission Enhancement in pH-Responsive 2:2 Cucurbit[8]uril Complexes
2019
Organic fluorophores, particularly stimuli-responsive molecules, are very interesting for biological and material sciences applications, but frequently limited by aggregation- and rotation-caused photoluminescence quenching. A series of easily accessible bipyridinium fluorophores, whose emission is quenched by a twisted intramolecular charge-transfer (TICT) mechanism, is reported. Encapsulation in a cucurbit[7]uril host gave a 1:1 complex exhibiting a moderate emission increase due to destabilization of the TICT state inside the apolar cucurbituril cavity. A much stronger fluorescence enhancement is observed in 2:2 complexes with the larger cucurbit[8]uril, which is caused by additional con…
Fingerprints from fingerprints
2003
Besides ‘‘classical’’ biological materials such as blood and sperm, epithelial cells from latent fingerprints are targeted in forensic sciences. In addition to studies using latent fingerprints applied to beer glasses [1], T-shirts left on crime scenes [2] and various other objects [3], we report the detection of STR profiles from latent fingerprints deposited on ordinary sheets of paper. In contrast to the relatively high number of epithelial cells from saliva or from excessively pressured fingerprints during strangulation [4,5], the experiments with latent fingerprints are expected to generate only a very small number of epithelial cells. Moreover, cells remaining on objects touched only …
Adsorptionsvoltammetrische Molybd�nbestimmung in biologischen Proben nach nassem Hochdruckaufschlu\
1989
The transfer of an (known from literature [141 and till now only applied to seawater) adsorption-voltammetric determination of molybdenum with oxine to biological samples, is described. The herewith accomplished changes of base solution resulted simultaneously in an optimization of the method with regard to interpretability and sensitivity. Special care was taken in the problem of decomposition. Best results are obtained with a high-pressure decomposition. Accuracy of analyses is confirmed with trials of recovery also in the biological matrix.
Metal speciation in solid matrices
1994
The literature on metal ion speciation in solid matrices is reviewed, taking into account its applications in the analysis of soil, sediment, biological materials, foodstuff and other solid samples. The pretreatment methods of various solid materials required for carrying out speciation studies have been highlighted. The basis of the methods of separation of different species from matrices, such as sequential extraction, selective extraction, etc. is discussed. The instrumental techniques used for the characterization of different chemical species in solid matrices have been mentioned. The literature survey reveals the analytical details of the developed methodologies, and these have been e…
Sperm Telomere Length in Men with Normal and Abnormal semen Parameters. A Pilot Study
2019
Objective: Male infertility is a growing social problem. The measurement of telomere length may be a new marker that can help to assess reproductive age of males and assess the chances of in vitro fertilization. Aim: The aim of our study was to investigate whether there are any differences between telomere length in men with normal and abnormal semen parameters. Materials and Methods: Telomere length was analyzed in 17 patients with normal and 28 patients with abnormal semen parameters using the telomeric repeat amplification protocol and Quantitative Real-Time Polymerase Chain Reaction (qPCR). Results: Mean sperm telomere length in all donors was 49±24kbp per haploid genome. However, patie…
Bio-imaging with the helium-ion microscope: A review
2021
Scanning helium-ion microscopy (HIM) is an imaging technique with sub-nanometre resolution and is a powerful tool to resolve some of the tiniest structures in biology. In many aspects, the HIM resembles a field-emission scanning electron microscope (FE-SEM), but the use of helium ions rather than electrons provides several advantages, including higher surface sensitivity, larger depth of field, and a straightforward charge-compensating electron flood gun, which enables imaging of non-conductive samples, rendering HIM a promising high-resolution imaging technique for biological samples. Starting with studies focused on medical research, the last decade has seen some particularly spectacular …
Application of the slurry technique to biological materials: a survey of literature
1991
The literature on the application of the slurry technique to biological materials is reviewed. It is obvious from the various applications that the most frequently employed atomization method for slurry analysis in biological materials is electrothermal atomization using either graphite tube or platform atomizers. The slurry technique is particularly useful when certified reference materials are not available and when the standard addition method is to be avoided. The literature survey revealed that this technique compares favourably with other methods for the determination of trace metals in biological materials.
Laser-Fabricated Fluorescent, Ligand-Free Silicon Nanoparticles: Scale-up, Biosafety, and 3D Live Imaging of Zebrafish under Development
2022
This work rationalizes the scalable synthesis of ultrasmall, ligand-free silicon nanomaterials via liquid-phase pulsed laser ablation process using picosecond pulses at ultraviolet wavelengths. Results showed that the irradiation time drives hydrodynamic NP size. Isolated, monodisperse Si-NPs are obtained at high yield (72%) using post-treatment process. The obtained Si-NPs have an average size of 10 nm (not aggregated) and display photoemission in the green spectral range. We directly characterized the ligand-free Si-NPs in a vertebrate animal (zebrafish) and assessed their toxicity during the development. In vivo assay revealed that Si-NPs are found inside in all the early life stages of …
Spatial distribution of two maternal messengers encoding two sea urchin cell surface proteins
1993
We have localized, byin situ hybridization, two messengers, called bepl and bep4 (butanol extracted proteins), coding for cell surface proteins, involved in cell interaction, in sections of eggs of the sea urchinP. lividus. These maternal RNAs are spatially distributed in a gradient with a maximum at one pole of the egg. These results represent the first demonstration of the existence of a gradient of informational molecules in the sea urchin egg,i.e., the biological material for which the gradient theory was first proposed.
Mass-spectrometric identification of primary biological particle markers: indication for low abundance of primary biological material in the pristine…
2011
Abstract. The abundance of marker compounds for primary biological particles in submicron aerosol was investigated by means of aerosol mass spectrometry. Mass spectra of amino acids, carbohydrates, small peptides, and proteins, all of which are key building blocks of biological particles, were recorded in laboratory experiments. Several characteristic marker peaks were identified. The identified marker peaks were compared with mass spectra recorded during AMAZE-08, a field campaign conducted in the pristine rainforest of the Central Amazon Basin, Brazil, during the wet season of February and March 2008. The low abundance of identified marker peaks places upper limits of 7.5 % for amino acid…